National Library of Energy BETA

Sample records for region nerc sub

  1. "Interconnection","NERC Regional Assesment Area"

    U.S. Energy Information Administration (EIA) Indexed Site

    projected by North American Electric Reliability Corporation Assessment Area," ... "Notes: * NERC region and reliability assessment area maps are provided on ...

  2. "January","NERC Regional Assesment Area"

    U.S. Energy Information Administration (EIA) Indexed Site

    demand, by North American Electric Reliability Corporation Assesment Area, " ... "Notes: * NERC region and reliability assessment area maps are provided on ...

  3. "Interconnection","NERC Regional Assesment Area","Summer"

    U.S. Energy Information Administration (EIA) Indexed Site

    peak load, by North American Electric Reliability Corporation Assessment Area," ... "Notes: * NERC region and reliability assessment area maps are provided on ...

  4. "Interconnection","NERC Regional Assesment Area","Summer"

    U.S. Energy Information Administration (EIA) Indexed Site

    2. Noncoincident peak load, by North American Electric Reliability Corporation Assessment Area," "1990-2011 actual, 2012-2016 projected" "megawatts" "Interconnection","NERC Regional Assesment Area","Summer" ,,"Actual",,,,,,,,,,,,,,,,,,,,,,,"Projected"

  5. "Interconnection","NERC Regional Assesment Area","Net Internal...

    U.S. Energy Information Administration (EIA) Indexed Site

    margins by North American Electric Reliability Corporation" "Region, 20012002-2014... margins by North American Electric Reliability Corporation" "Region, 20012002-2014...

  6. Property:EIA/861/NercLocation | Open Energy Information

    Open Energy Info (EERE)

    type String. Description: Nerc Location NERC Location: The North American Electric Reliability Corporation (NERC) region where the utility has its primary business operations...

  7. "Interconnection","NERC Regional Assesment Area"

    U.S. Energy Information Administration (EIA) Indexed Site

    1. Net Energy for load, actual and projected by North American Electric Reliability Corporation Assessment Area," "1990-2011 actual, 2012-2016 projected" "thousands of megawatthours" "Interconnection","NERC Regional Assesment Area" ,,1990,1991,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001,2002,2003,2004,2005,2006,2007,2008,2009,2010,2011,"2012E","2013E","2014E","2015E","2016E" "Eastern

  8. "January","NERC Regional Assesment Area"

    U.S. Energy Information Administration (EIA) Indexed Site

    A.1. January monthly peak hour demand, by North American Electric Reliability Corporation Assesment Area, " "1996-2011 actual, 2012-2013 projected" "megawatts" "January","NERC Regional Assesment Area" ,,"Actual" ,,1996,1997,1998,1999,2000,2001,2002,2003,2004,2005,2006,2007,2008,2009,2010,2011 "Eastern Interconnection","FRCC",39860,37127,27122,38581,37521,40258,39675,45033,35545,41247,34464,38352,41705,44945,53093,46086

  9. "Interconnection","NERC Regional Assesment Area","Net Internal Demand[1] -- Winter"

    U.S. Energy Information Administration (EIA) Indexed Site

    B Winter net internal demand, capacity resources, and capacity margins by North American Electric Reliability Corporation" "Region, 2001-2011 actual, 2012-2016 projected" "megawatts and percent" "Interconnection","NERC Regional Assesment Area","Net Internal Demand[1] -- Winter" ,,"Actual",,,,,,,,,,,"Projected" ,,"2001/ 2002","2002/ 2003","2003/ 2004","2004/ 2005","2005/

  10. Property:EIA/861/NercNpcc | Open Energy Information

    Open Energy Info (EERE)

    Description: Nerc Npcc Entity conducts business operations within the NPCC region (Y or N) 1 References EIA Form EIA-861 Final Data File for 2008 - F861 File...

  11. Property:EIA/861/NercFrcc | Open Energy Information

    Open Energy Info (EERE)

    Description: Nerc Frcc Entity conducts business operations within the FRCC region (Y or N) 1 References EIA Form EIA-861 Final Data File for 2008 - F861 File...

  12. Microsoft PowerPoint - SWL NERC status june 2009.ppt

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    CORPS OF ENGINEERS SOUTHWEST REGION NERC ACTIVITIES SOUTHWESTERN FEDERAL HYDROPOWER CONFERENCE 2 COE Status of NERC Background * 2005 - Energy Policy Act Passed * March 2007 - Final ruling for mandatory Reliability Standards * May 2007 - HQUSACE establishes National Project Delivery Team to Develop Corporate approach to Reliability Standards (ACE-CME) * June 2007 - Reliability Standards Effective 3 COE Status of NERC Initial Development * New ER and EP Developed. * Individual Districts are

  13. North American Electric Reliability Corporation (NERC): Reliability...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    (NERC): Reliability Considerations from the Integration of Smart Grid North American Electric Reliability Corporation (NERC): Reliability Considerations from the Integration of ...

  14. Property:EIA/861/NercWecc | Open Energy Information

    Open Energy Info (EERE)

    operations within the WECC region (Y or N) 1 References EIA Form EIA-861 Final Data File for 2008 - F861 File Layout-2008.doc Pages using the property "EIA861NercWecc"...

  15. Property:EIA/861/NercRfc | Open Energy Information

    Open Energy Info (EERE)

    operations within the RFC region (Y or N) 1 References EIA Form EIA-861 Final Data File for 2008 - F861 File Layout-2008.doc Pages using the property "EIA861NercRfc"...

  16. Property:EIA/861/NercSpp | Open Energy Information

    Open Energy Info (EERE)

    operations within the SPP region (Y or N) 1 References EIA Form EIA-861 Final Data File for 2008 - F861 File Layout-2008.doc Pages using the property "EIA861NercSpp"...

  17. Learn About NercEnergy - Nercenergy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Learn About NercEnergy Energy to code...energy to program...energy to create. Founded as a technical think tank, NercEnergy is about putting the best minds in tech together to help...

  18. North American Electric Reliability Corporation (NERC): Reliability

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Considerations from the Integration of Smart Grid | Department of Energy (NERC): Reliability Considerations from the Integration of Smart Grid North American Electric Reliability Corporation (NERC): Reliability Considerations from the Integration of Smart Grid North American Electric Reliability Corporation (NERC): Reliability Considerations from the Integration of Smart Grid. NERC develops and enforces Reliability Standards; assesses adequacy annually via a ten-year forcast and winter and

  19. Wireless System Considerations When Implementing NERC Critical

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Infrastructure Protection Standards | Department of Energy Wireless System Considerations When Implementing NERC Critical Infrastructure Protection Standards Wireless System Considerations When Implementing NERC Critical Infrastructure Protection Standards Energy asset owners are facing a monumental challenge as they address compliance with the North American Electric Reliability Corporation (NERC) Critical Infrastructure Protection (CIP) Standards (CIP-002 through CIP-009). The increased

  20. NERC Presentation: Accommodating High Levels of Variable Generation...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    NERC Presentation: Accommodating High Levels of Variable Generation, October 29, 2010 NERC Presentation: Accommodating High Levels of Variable Generation, October 29, 2010 North ...

  1. NercEnergy, Author at Nercenergy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Author: NercEnergy Tips for Understanding the Relationship Between a Web Application and SLAs At the heart of any Service Level Agreement is the descriptions of the services you provided as well as the expectations a customer and business have regarding their work relationship. This is carried out by defining specific metrics regarding how parameters are measured as well as any and all guarantees. Generally, an SLA is a contract between a company and a customer, but it may also bet between

  2. Comments of North American Electric Reliability Corporation (NERC) to DOE

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Smart Grid RFI: Addressing Policy and Logistical Challenges | Department of Energy North American Electric Reliability Corporation (NERC) to DOE Smart Grid RFI: Addressing Policy and Logistical Challenges Comments of North American Electric Reliability Corporation (NERC) to DOE Smart Grid RFI: Addressing Policy and Logistical Challenges Response to the Department of Energy's ("DOE") Request for Information (RFI) regarding the "Smart Grid RFI: Addressing Policy and Logistical

  3. NERC Presentation: Accommodating High Levels of Variable Generation, October 29, 2010

    Broader source: Energy.gov [DOE]

    North American Electric Reliability Corporation (NERC) presentation to the Electricity Advisory Committee, October 29, 2010, on accommodating high levels of variable electricity eneration. Variable...

  4. Property:EIA/861/NercErcot | Open Energy Information

    Open Energy Info (EERE)

    Regional Entity (formerly ERCOT) (Y or N) 1 References EIA Form EIA-861 Final Data File for 2008 - F861 File Layout-2008.doc Pages using the property "EIA861...

  5. Microsoft PowerPoint - NERC Reliability Standards and Mandatory Compliance Presentation to Hydro-Power Conference - June 2007.p

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    NERC Reliability NERC Reliability Standards and Standards and Mandatory Compliance Mandatory Compliance Hydro Hydro - - Power Conference Power Conference June 13, 2007 June 13, 2007 Stan Mason Stan Mason 2 EPACT 2005 EPACT 2005 Congress approved the related legislation Congress approved the related legislation in August 2005 in August 2005 It required creation of an Electric It required creation of an Electric Reliability Organization (ERO) to be Reliability Organization (ERO) to be approved by

  6. NERC 101

    U.S. Energy Information Administration (EIA) Indexed Site

    Infrastructure: Electric Power Infrastructure: Status and Challenges for the Future Status and Challenges for the Future Mark Lauby Director, Reliability Assessments and Performance Analysis Owners, Operators, and Users  2005 Energy Policy Act: * All users, owners, and operators of the bulk-power system shall comply with reliability standards  FERC Rule * All entities subject to the Commission's reliability jurisdiction... (users, owners, and operators of the bulk-power system) shall

  7. NERC-LV-539-17 OFF-SITE SURVEILLANCE ACTIVXTPES OF Tm

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    7 OFF-SITE SURVEILLANCE ACTIVXTPES OF Tm c? NATIONAL ENVIR0NMENTA.L RESEARCH CENT.ER from July through December 197C A *: l p- by o&toring '"'a~ Operations Laboratov ..%)qr- i wtional Environmental Research Cen& ,& 0 U. S. ENVIRONMENTAL ?l%TECTION AGENCY - l l . .-.-w ._- .-- -- This work perfbrmed unde>T Memorandum of Understanding No. AT(26-l)-539 for the U. So ATOMIC ENERGY COlQ4ISSION l NERC-LV-539-17 OFF-SITE SURVEILLANCE ACTIVITIES OF THE NATIONAL ENVIRONMEN'Q!L

  8. Optical properties of La{sub 2}CuO{sub 4} and La{sub 2-x}Ca{sub x}CuO{sub 4} crystallites in UV-vis-NIR region synthesized by sol-gel process

    SciTech Connect (OSTI)

    Li Yifeng; Huang Jianfeng Cao Liyun; Wu Jianpeng; Fei Jie

    2012-02-15

    La{sub 2}CuO{sub 4} and La{sub 2-x}Ca{sub x}CuO{sub 4} crystallites were prepared via a simple sol-gel process. The as-prepared La{sub 2}CuO{sub 4} and La{sub 2} {sub -x}Ca{sub x}CuO{sub 4} crystallites were characterized by X-ray diffraction, transmission electron microscope and UV-vis-NIR spectra. Results show that the grain size of La{sub 2}CuO{sub 4} crystallites increases with the increase of heat treatment temperature from 600 Degree-Sign C to 800 Degree-Sign C. Optical properties show that La{sub 2}CuO{sub 4} crystallites have broad absorption both in the UV-vis region and in the NIR region. The band gap of the as-prepared crystallites decreases from 1.367 eV to 1.284 eV with the increase of calcination temperature from 600 Degree-Sign C to 800 Degree-Sign C. In the series of La{sub 2-x}Ca{sub x}CuO{sub 4} compounds (x = 0.05, 0.08, 0.10, 0.12, 0.15 and 0.20), all of the samples exhibit an orthogonal crystal structure and the solubility limit of Ca{sup 2+} in La{sub 2}CuO{sub 4} is within the range of x = 0.12-0.15. In the whole UV-vis-NIR region, La{sub 2-x}Ca{sub x}CuO{sub 4} crystallites exhibit a broad absorption and the corresponding band gap first increases and then decreases with increasing of Ca{sup 2+} content. - Highlights: Black-Right-Pointing-Pointer The optical band gap can be tuned by adjusting the grain size and Ca{sup 2+} content. Black-Right-Pointing-Pointer La{sub 2}CuO{sub 4} crystallites exhibit a broad absorption band both in the UV-vis region and in the NIR region. Black-Right-Pointing-Pointer The band gap increases from 1.284 eV to 1.319 eV with the decrease of heat treatment temperature. Black-Right-Pointing-Pointer In the whole UV-vis-NIR region, the La{sub 2-x}Ca{sub x}CuO{sub 4} crystallites displayed a broad absorption. Black-Right-Pointing-Pointer The band gap of La{sub 2-x}Ca{sub x}CuO{sub 4} increases linearly with doping level when 0 {<=} x {<=} 0.12.

  9. Reactive power interconnection requirements for PV and wind plants : recommendations to NERC.

    SciTech Connect (OSTI)

    McDowell, Jason; Walling, Reigh; Peter, William; Von Engeln, Edi; Seymour, Eric; Nelson, Robert; Casey, Leo; Ellis, Abraham; Barker, Chris.

    2012-02-01

    Voltage on the North American bulk system is normally regulated by synchronous generators, which typically are provided with voltage schedules by transmission system operators. In the past, variable generation plants were considered very small relative to conventional generating units, and were characteristically either induction generator (wind) or line-commutated inverters (photovoltaic) that have no inherent voltage regulation capability. However, the growing level of penetration of non-traditional renewable generation - especially wind and solar - has led to the need for renewable generation to contribute more significantly to power system voltage control and reactive power capacity. Modern wind-turbine generators, and increasingly PV inverters as well, have considerable dynamic reactive power capability, which can be further enhanced with other reactive support equipment at the plant level to meet interconnection requirements. This report contains a set of recommendations to the North-America Electricity Reliability Corporation (NERC) as part of Task 1-3 (interconnection requirements) of the Integration of Variable Generation Task Force (IVGTF) work plan. The report discusses reactive capability of different generator technologies, reviews existing reactive power standards, and provides specific recommendations to improve existing interconnection standards.

  10. WRF-Chem model predictions of the regional impacts of N<sub>2sub>O>5sub> heterogeneous processes on night-time chemistry over north-western Europe

    SciTech Connect (OSTI)

    Lowe, Douglas; Archer-Nicholls, Scott; Morgan, Will; Allan, James D.; Utembe, Steve; Ouyang, Bin; Aruffo, Eleonora; Le Breton, Michael; Zaveri, Rahul A.; di Carlo, Piero; Percival, Carl; Coe, H.; Jones, Roderic L.; McFiggans, Gordon

    2015-02-09

    Chemical modelling studies have been conducted over north-western Europe in summer conditions, showing that night-time dinitrogen pentoxide (N<sub>2sub>O>5sub>) heterogeneous reactive uptake is important regionally in modulating particulate nitrate and has a~modest influence on oxidative chemistry. Results from Weather Research and Forecasting model with Chemistry (WRF-Chem) model simulations, run with a detailed volatile organic compound (VOC) gas-phase chemistry scheme and the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) sectional aerosol scheme, were compared with a series of airborne gas and particulate measurements made over the UK in July 2010. Modelled mixing ratios of key gas-phase species were reasonably accurate (correlations with measurements of 0.70.9 for NO<sub>2sub> and O<sub>3sub>). However modelled loadings of particulate species were less accurate (correlation with measurements for particulate sulfate and ammonium were between 0.0 and 0.6). Sulfate mass loadings were particularly low (modelled means of 0.50.7 ?g kg?1<sub>air>, compared with measurements of 1.01.5 ?g kg?1<sub>air>). Two flights from the campaign were used as test cases one with low relative humidity (RH) (6070%), the other with high RH (8090%). N<sub>2sub>O>5sub> heterogeneous chemistry was found to not be important in the low-RH test case; but in the high-RH test case it had a strong effect and significantly improved the agreement between modelled and measured NO<sub>3sub> and N<sub>2sub>O>5sub>. When the model failed to capture atmospheric RH correctly, the modelled NO<sub>3sub> and N<sub>2sub>O>5sub> mixing ratios for these flights differed significantly from the measurements. This demonstrates that, for regional modelling which involves heterogeneous processes, it is essential to capture the ambient temperature and water vapour profiles.

    The night-time NO<sub>3sub> oxidation of VOCs across the whole region was found to be 100300 times slower than the daytime OH oxidation of these compounds. The difference in contribution was less for alkenes ( 80) and comparable for dimethylsulfide (DMS). However the suppression of NO<sub>3sub> mixing ratios across the domain by N<sub>2sub>O>5sub> heterogeneous chemistry has only a very slight, negative, influence on this oxidative capacity. The influence on regional particulate nitrate mass loadings is stronger. Night-time N<sub>2sub>O>5sub> heterogeneous chemistry maintains the production of particulate nitrate within polluted regions: when this process is taken into consideration, the daytime peak (for the 95th percentile) of PM<sub>10sub> nitrate mass loadings remains around 5.6 ?g kg?1<sub>air>, but the night-time minimum increases from 3.5 to 4.6 ?g kg?1<sub>air>. The sustaining of higher particulate mass loadings through the night by this process improves model skill at matching measured aerosol nitrate diurnal cycles and will negatively impact on regional air quality, requiring this process to be included in regional models.

  11. Applicability of the “Gallet equation” to the vegetation clearances of NERC Reliability Standard FAC-003-2

    SciTech Connect (OSTI)

    Kirkham, Harold

    2012-03-31

    NERC has proposed a standard to use to specify clearances between vegetation and power lines. The purpose of the rule is to reduce the probability of flashover to a calculably low level. This report was commissioned by FERC’s Office of Electrical Reliability. The scope of the study was analysis of the mathematics and documentation of the technical justification behind the application of the Gallet equation and the assumptions used in the technical reference paper

  12. Regional partnerships to sequester CO{sub 2} at near-commercial scale

    SciTech Connect (OSTI)

    2008-07-01

    A summary of the keynote speech by Acting Deputy Secretary of Energy, Jeffrey Kupfer, is given, as well as details about new agreements on CO{sub 2} injection. These include the West Coast Regional Carbon Sequestration Partnership agreement to locate CO{sub 2} injection with a 50 mw clean energy systems plant in Kumberlina, California, and the Plains CO{sub 2} Reduction Partnership and Southeast Regional Carbon Sequestration PARTNERSHIP plans to inject CO{sub 2} derived from post combustion capture at power plants. 3 photos.

  13. Source sector and region contributions to BC and PM<sub>2.5sub> in Central Asia

    SciTech Connect (OSTI)

    Kulkarni, S.; Sobhani, N.; Miller-Schulze, J. P.; Shafer, M. M.; Schauer, J. J.; Solomon, P. A.; Saide, P. E.; Spak, S. N.; Cheng, Y. F.; Denier van der Gon, H. A. C.; Lu, Z.; Streets, D. G.; Janssens-Maenhout, G.; Wiedinmyer, C.; Lantz, J.; Artamonova, M.; Chen, B.; Imashev, S.; Sverdlik, L.; Deminter, J. T.; Adhikary, B.; D'Allura, A.; Wei, C.; Carmichael, G. R.

    2015-02-18

    Particulate matter (PM) mass concentrations, seasonal cycles, source sector, and source region contributions in Central Asia (CA) are analyzed for the period April 2008–July 2009 using the Sulfur Transport and dEposition Model (STEM) chemical transport model and modeled meteorology from the Weather Research and Forecasting (WRF) model. Predicted aerosol optical depth (AOD) values (annual mean value ~0.2) in CA vary seasonally, with lowest values in the winter. Surface PM<sub>2.5sub> concentrations (annual mean value ~10 μg m-3) also exhibit a seasonal cycle, with peak values and largest variability in the spring/summer, and lowest values and variability in the winter (hourly values from 2 to 90 μg m-3). Surface concentrations of black carbon (BC) (mean value ~0.1 μg m-3) show peak values in the winter. The simulated values are compared to surface measurements of AOD as well as PM<sub>2.5sub>, PM<sub>10sub>, BC, and organic carbon (OC) mass concentrations at two regional sites in Kyrgyzstan (Lidar Station Teplokluchenka (LST) and Bishkek). The predicted values of AOD and PM mass concentrations and their seasonal cycles are fairly well captured. The carbonaceous aerosols are underpredicted in winter, and analysis suggests that the winter heating emissions are underestimated in the current inventory. Dust, from sources within and outside CA, is a significant component of the PM mass and drives the seasonal cycles of PM and AOD. On an annual basis, the power and industrial sectors are found to be the most important contributors to the anthropogenic portion of PM<sub>2.5sub>. Residential combustion and transportation are shown to be the most important sectors for BC. Biomass burning within and outside the region also contributes to elevated PM and BC concentrations. The analysis of the transport pathways and the variations in particulate matter mass and composition in CA demonstrates that this region is strategically located to characterize regional and intercontinental transport of pollutants. Aerosols at these sites are shown to reflect dust, biomass burning, and anthropogenic sources from Europe; South, East, and Central Asia; and Russia depending on the time period. Simulations for a reference 2030 emission scenario based on pollution abatement measures already committed to in current legislation show that PM<sub>2.5sub> and BC concentrations in the region increase, with BC growing more than PM<sub>2.5sub> on a relative basis. This suggests that both the health impacts and the climate warming associated with these particles may increase over the next decades unless additional control measures are taken. The importance of observations in CA to help characterize the changes that are rapidly taking place in the region are discussed.

  14. Rocky Mountain Regional CO{sub 2} Storage Capacity and Significance

    SciTech Connect (OSTI)

    Laes, Denise; Eisinger, Chris; Esser, Richard; Morgan, Craig; Rauzi, Steve; Scholle, Dana; Matthews, Vince; McPherson, Brian

    2013-08-30

    The purpose of this study includes extensive characterization of the most promising geologic CO{sub 2} storage formations on the Colorado Plateau, including estimates of maximum possible storage capacity. The primary targets of characterization and capacity analysis include the Cretaceous Dakota Formation, the Jurassic Entrada Formation and the Permian Weber Formation and their equivalents in the Colorado Plateau region. The total CO{sub 2} capacity estimates for the deep saline formations of the Colorado Plateau region range between 9.8 metric GT and 143 metric GT, depending on assumed storage efficiency, formations included, and other factors.

  15. Integrated geophysical and geomicrobial surveys, Chapare region, Sub-Andean Boliva

    SciTech Connect (OSTI)

    Widdoes, D.; Verteuil, N. de; Hitzman, D.

    1996-12-31

    Approximately 4800 square kilometers of the Chapare region of Sub-Andean, Bolivia were surveyed in 1994 using combined 2-D seismic and geomicrobial surface geochemistry. The Microbial Oil Survey Technique, M.O.S.T., measures evidence of hydrocarbon microseepage by evaluating surface soils for butane associated microorganisms. Approximately 615 kilometers of seismic and over 2500 soil samples were collected for this integrated reconnaissance survey. Elevated microbial populations of these specific microorganisms indicate anomalous hydrocarbon microseepage is leaking from hydrocarbon accumulations. Integration of the geomicrobial data with geological and geophysical data was completed. Parallel seismic and microbial traverses revealed significant areas of structural targets. A portion of the frontier study area demonstrates strong hydrocarbon microseepage which aligns with geophysical targets. A fault system identified from seismic interpretation was also mapped by distinct microbial anomalies at the surface. Comparative profiles and survey maps link microbial anomalies with geological and geophysical targets.

  16. Integrated geophysical and geomicrobial surveys, Chapare region, Sub-Andean Boliva

    SciTech Connect (OSTI)

    Widdoes, D. ); Verteuil, N. de ); Hitzman, D. )

    1996-01-01

    Approximately 4800 square kilometers of the Chapare region of Sub-Andean, Bolivia were surveyed in 1994 using combined 2-D seismic and geomicrobial surface geochemistry. The Microbial Oil Survey Technique, M.O.S.T., measures evidence of hydrocarbon microseepage by evaluating surface soils for butane associated microorganisms. Approximately 615 kilometers of seismic and over 2500 soil samples were collected for this integrated reconnaissance survey. Elevated microbial populations of these specific microorganisms indicate anomalous hydrocarbon microseepage is leaking from hydrocarbon accumulations. Integration of the geomicrobial data with geological and geophysical data was completed. Parallel seismic and microbial traverses revealed significant areas of structural targets. A portion of the frontier study area demonstrates strong hydrocarbon microseepage which aligns with geophysical targets. A fault system identified from seismic interpretation was also mapped by distinct microbial anomalies at the surface. Comparative profiles and survey maps link microbial anomalies with geological and geophysical targets.

  17. Coordinated NO{sub x} control strategies: Phase II Title IV, ozone transport region and ozone transport assessment group

    SciTech Connect (OSTI)

    Frazier, W.F.; Dunn, R.M.; Baublis, D.C.

    1998-12-31

    Many electric utilities are faced with future nitrogen oxides (NO{sub x}) reduction requirements. In some instances, these utilities will be affected by multiple regulatory programs. For example, numerous fossil fired plants must comply with Phase II of Title IV of the Clean Air Act Amendments of 1990 (CAAA), state NO{sub x} rules as a result of the recommendations of the Ozone Transport Commission (OTC) and future requirements of the Proposed Rule for Reducing Regional Transport of Ground-Level Ozone (Ozone Transport SIP Rulemaking). This paper provides an overview of NO{sub x} regulatory programs, NO{sub x} compliance planning concepts, and NO{sub x} control technology options that could be components of an optimized compliance strategy.

  18. Measurement of the Proton and Deuteron Spin Structure Function {ital g}{sub 1} in the Resonance Region

    SciTech Connect (OSTI)

    Arnold, R.; Bosted, P.; Dunne, J.; Fellbaum, J.; Reyna, D.; Rock, S.; Spengos, M.; Szalata, Z.; White, J.; Feltham, A.; Sick, I.; Steiner, P.; Zihlmann, B.; Breton, V.; Comptour, C.; Fonvieille, H.; Roblin, Y.; Borel, H.; Grenier, P.; Lombard-Nelsen, R.; Marroncle, J.; Morgenstern, J.; Staley, F.; Terrien, Y.; Dietrich, F.; Bauer, J.; Button-Shafer, J.; Chen, J.; Chupp, T.; Coulter, K.; Smith, T.; Garvey, D.; Maruyama, X.; Hyde-Wright, C.; Klein, A.; Kuhn, S.; Raue, B.; Wesselmann, F.; Antonov, R.; Griffioen, K.; Petratos, G.; Raines, P.; Spengos, M.; Akagi, T.; Anthony, P.; Clendenin, J.; Court, G.; Daoudi, M.; Dutz, H.; Erbacher, R.; Gearhart, R.; Hughes, E.; Maruyama, T.; Meyer, W.; Petratos, G.; Pitthan, R.; Prescott, C.; Rijllart, A.; Rochester, L.; St.Lorant, S.; Stuart, L.; Tang, H.; Usher, T.; Walz, D.; White, J.; Witte, K.; Young, C.; Youngman, B.; Erbacher, R.; Kawall, D.; Meziani, Z.; Meziani, Z.; Abe, K.

    1997-02-01

    We have measured the proton and deuteron spin structure functions g{sup p}{sub 1} and g{sup d}{sub 1} in the region of the nucleon resonances for W{sup 2}{lt}5 GeV{sup 2} and Q{sup 2}{approx_equal}0.5 and Q{sup 2}{approx_equal}1.2 GeV{sup 2} by inelastically scattering 9.7 GeV polarized electrons off polarized {sup 15}NH{sub 3} and {sup 15}ND{sub 3} targets. We observe significant structure in g{sup p}{sub 1} in the resonance region. We have used the present results, together with the deep-inelastic data at higher W{sup 2}, to extract {Gamma}(Q{sup 2}){equivalent_to}0=g{sub 1}(x,Q{sup 2})dx. This is the first information on the low-Q{sup 2} evolution of {Gamma} toward the Gerasimov-Drell-Hearn limit at Q{sup 2}=0. {copyright} {ital 1997} {ital The American Physical Society}

  19. The NO{sub x} Budget trading program: a collaborative, innovative approach to solving a regional air pollution problem

    SciTech Connect (OSTI)

    Napolitano, Sam; Stevens, Gabrielle; Schreifels, Jeremy; Culligan, Kevin

    2007-11-15

    The NO{sub x} Budget Trading Program showed that regional cap-and-trade programs are adaptable to more than one pollutant, time period, and geographic scale, and can achieve compliance results similar to the Acid Rain Program. Here are 11 specific lessons that have emerged from the experience. (author)

  20. Buildings Energy Data Book: 6.2 Electricity Generation, Transmission, and Distribution

    Buildings Energy Data Book [EERE]

    8 NERC Regions Map Source(s): North American Reliability Corporation, NERC Regions Map Feb. 2012, http://www.nerc.com/fileUploads/File/AboutNERC/maps/NERC_Regions_color.jpg

  1. Vector analyzing power of {pi}{sup +7}Li scattering in the region of the {delta}{sub 33} resonance

    SciTech Connect (OSTI)

    Ibraeva, E. T.; Zhusupov, M. A.; Zaykin, A. Yu.; Imambekov, O.

    2006-04-15

    Within Glauber diffraction theory, the vector analyzing power iT{sub 11} is calculated at three energies of positively charged pions, 134, 164, and 194 MeV, incident to {sup 7}Li nuclei. These energy values lie in the region of the {delta}{sub 33} resonance in {pi}{sup {+-}}N interaction, the resonance maximum being at 180 MeV. The calculation of iT{sub 11} was performed with several model {sup 7}Li wave functions, including the {alpha}t-cluster and shell-model ones. The properties of {pi}{sup +7}Li scattering are found to be sensitive to the structural features of the target nucleus. A comparison of the results of the calculations with experimental data shows that the wave functions in question and the potentials used to calculate them are quite appropriate.

  2. Electronic state spectroscopy of diiodomethane (CH{sub 2}I{sub 2}): Experimental and computational studies in the 30?00095?000 cm{sup ?1} region

    SciTech Connect (OSTI)

    Mandal, Anuvab; Jagatap, B. N.; Singh, Param Jeet; Shastri, Aparna

    2014-05-21

    The electronic absorption spectrum of diiodomethane in the 30?00095?000 cm{sup ?1} region is investigated using synchrotron radiation; the spectrum in the 50?00066?500 cm{sup ?1} region is reported for the first time. The absorption bands in the 30?00050?000 cm{sup ?1} region are attributed to valence transitions, while the vacuum ultraviolet (VUV) spectrum (50?00095?000 cm{sup ?1}) is dominated by several Rydberg series converging to the first four ionization potentials of CH{sub 2}I{sub 2} at 9.46, 9.76, 10.21, and 10.56 eV corresponding to the removal of an electron from the outermost 3b{sub 2}, 2b{sub 1}, 1a{sub 2}, and 4a{sub 1} non-bonding orbitals, respectively. Rydberg series of ns, np, and nd type converging to each of the four ionization potentials are assigned based on a quantum defect analysis. Time dependent density functional theory calculations of excited states support the analysis and help in interpretation of the Rydberg and valence nature of observed transitions. Density functional theory calculations of the neutral and ionic ground state geometries and vibrational frequencies are used to assign the observed vibronic structure. Vibronic features accompanying the Rydberg series are mainly due to excitation of the C-I symmetric stretch (?{sub 3}) and CH{sub 2} wag (?{sub 8}) modes, with smaller contributions from the C-H symmetric stretch (?{sub 1}). UV absorption bands are assigned to low lying valence states 1{sup 1}B{sub 2}, 1{sup 1}B{sub 1}, 2{sup 1}A{sub 1}, 3{sup 1}A{sub 1}, 2{sup 1}B{sub 1}, and 2{sup 1}B{sub 2} and the unusually high underlying intensity in parts of the VUV spectrum is attributed to valence states with high oscillator strength. This is the first report of a comprehensive Rydberg series and vibronic analysis of the VUV absorption spectrum of CH{sub 2}I{sub 2} in the 50?00085?000 cm{sup ?1} region. The VUV absorption spectrum of CD{sub 2}I{sub 2} which serves to verify and consolidate spectral assignments is also reported here for the first time.

  3. K{sub S} Lambda Photoproduction On The Neutron Within The Resonance Region

    SciTech Connect (OSTI)

    Taylor, Charles E.; Cole, Philip L.

    2014-01-01

    We report some preliminary differential cross section results for the gammad --> K{sub S} Lambda(p) reaction using a circularly-polarized photon beam and an unpolarized LD{sub 2} target. The data was collected at the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. For this study the photon energy ranged from 1.3 to 2.53 GeV, which covers from the reaction threshold through the nucleon resonance regimes. The acceptance- and flux-corrected yields show peaks at the center-of mass energies W = 1.7 and W = 1.9 GeV. These first-time results will aid in unraveling the spectrum of non-strange excited baryons.

  4. SIMULATION FRAMEWORK FOR REGIONAL GEOLOGIC CO{sub 2} STORAGE ALONG ARCHES PROVINCE OF MIDWESTERN UNITED STATES

    SciTech Connect (OSTI)

    Sminchak, Joel

    2012-09-30

    This report presents final technical results for the project Simulation Framework for Regional Geologic CO{sub 2} Storage Infrastructure along Arches Province of the Midwest United States. The Arches Simulation project was a three year effort designed to develop a simulation framework for regional geologic carbon dioxide (CO{sub 2}) storage infrastructure along the Arches Province through development of a geologic model and advanced reservoir simulations of large-scale CO{sub 2} storage. The project included five major technical tasks: (1) compilation of geologic, hydraulic and injection data on Mount Simon, (2) development of model framework and parameters, (3) preliminary variable density flow simulations, (4) multi-phase model runs of regional storage scenarios, and (5) implications for regional storage feasibility. The Arches Province is an informal region in northeastern Indiana, northern Kentucky, western Ohio, and southern Michigan where sedimentary rock formations form broad arch and platform structures. In the province, the Mount Simon sandstone is an appealing deep saline formation for CO{sub 2} storage because of the intersection of reservoir thickness and permeability. Many CO{sub 2} sources are located in proximity to the Arches Province, and the area is adjacent to coal fired power plants along the Ohio River Valley corridor. Geophysical well logs, rock samples, drilling logs, and geotechnical tests were evaluated for a 500,000 km{sup 2} study area centered on the Arches Province. Hydraulic parameters and historical operational information was also compiled from Mount Simon wastewater injection wells in the region. This information was integrated into a geocellular model that depicts the parameters and conditions in a numerical array. The geologic and hydraulic data were integrated into a three-dimensional grid of porosity and permeability, which are key parameters regarding fluid flow and pressure buildup due to CO{sub 2} injection. Permeability data were corrected in locations where reservoir tests have been performed in Mount Simon injection wells. The geocellular model was used to develop a series of numerical simulations designed to support CO{sub 2} storage applications in the Arches Province. Variable density fluid flow simulations were initially run to evaluate model sensitivity to input parameters. Two dimensional, multiple-phase simulations were completed to evaluate issues related to arranging injection fields in the study area. A basin-scale, multiple-phase model was developed to evaluate large scale injection effects across the region. Finally, local scale simulations were also completed with more detailed depiction of the Eau Claire formation to investigate to the potential for upward migration of CO{sub 2}. Overall, the technical work on the project concluded that injection large-scale injection may be achieved with proper field design, operation, siting, and monitoring. Records from Mount Simon injection wells were compiled, documenting more than 20 billion gallons of injection into the Mount Simon formation in the Arches Province over the past 40 years, equivalent to approximately 60 million metric tons CO2. The multi-state team effort was useful in delineating the geographic variability in the Mount Simon reservoir properties. Simulations better defined potential well fields, well field arrangement, CO{sub 2} pipeline distribution system, and operational parameters for large-scale injection in the Arches Province. Multiphase scoping level simulations suggest that injection fields with arrays of 9 to 50+ wells may be used to accommodate large injection volumes. Individual wells may need to be separated by 3 to 10 km. Injection fields may require spacing of 25 to 40 km to limit pressure and saturation front interference. Basin-scale multiple-phase simulations in STOMP reflect variability in the Mount Simon. While simulations suggest a total injection rate of 100 million metric tons per year (approximately to a 40% reduction of CO{sub 2} emissions from large point sources across the Arches Province) may be feasible, some areas are more suitable due to favorable geology. Sustainable injection rates were higher in areas where there was higher thickness and reservoir permeability. Distribution of injection across well fields is an effective method to reduce pressure and CO{sub 2} saturation front interference.

  5. ,"Table 4.B Winter Net Internal Demand, Capacity Resources, and Capacity Margins by North American Electric Reliability Corporation Region,"

    U.S. Energy Information Administration (EIA) Indexed Site

    B Winter Net Internal Demand, Capacity Resources, and Capacity Margins by North American Electric Reliability Corporation Region," ,"2001-2010 Actual, 2011-2015 Projected" ,"(Megawatts and Percent)" ,"Interconnection","NERC Regional Assesment Area","Net Internal Demand[1] -- Winter" ,,,"Actual",,,,,,,,,,"Projected"

  6. HIGH D{sub 2}O/HDO RATIO IN THE INNER REGIONS OF THE LOW-MASS PROTOSTAR NGC1333 IRAS2A

    SciTech Connect (OSTI)

    Coutens, A.; Jrgensen, J. K.; Persson, M. V.; Van Dishoeck, E. F.; Vastel, C.; Taquet, V.

    2014-09-01

    Water plays a crucial role both in the interstellar medium and on Earth. To constrain its formation mechanisms and its evolution through the star formation process, the determination of the water deuterium fractionation ratios is particularly suitable. Previous studies derived HDO/H{sub 2}O ratios in the warm inner regions of low-mass protostars. We here report a detection of the D{sub 2}O 1{sub 1,} {sub 0}-1{sub 0,} {sub 1} transition toward the low-mass protostar NGC1333 IRAS2A with the Plateau de Bure interferometer: this represents the first interferometric detection of D{sub 2}Oand only the second solar-type protostar for which this isotopologue is detected. Using the observations of the HDO 5{sub 4,} {sub 2}-6{sub 3,} {sub 3} transition simultaneously detected and three other HDO lines previously observed, we show that the HDO line fluxes are well reproduced with a single excitation temperature of 218 21K and a source size of ?0.''5. The D{sub 2}O/HDO ratio is ?(1.2 0.5)נ10{sup 2}, while the use of previous H{sub 2}{sup 18}O observations give an HDO/H{sub 2}O ratio of ?(1.7 0.8)נ10{sup 3}, i.e., a factor of seven lower than the D{sub 2}O/HDO ratio. These results contradict the predictions of current grain surface chemical models and indicate that either the surface deuteration processes are poorly understood or that both sublimation of grain mantles and water formation at high temperatures (?230K) take place in the inner regions of this source. In the second scenario, the thermal desorption of the grain mantles would explain the high D{sub 2}O/HDO ratio, while water formation at high temperature would explain significant extra production of H{sub 2}O leading to a decrease of the HDO/H{sub 2}O ratio.

  7. SIMULATION FRAMEWORK FOR REGIONAL GEOLOGIC CO{sub 2} STORAGE ALONG ARCHES PROVINCE OF MIDWESTERN UNITED STATES

    SciTech Connect (OSTI)

    Sminchak, Joel

    2012-09-30

    This report presents final technical results for the project Simulation Framework for Regional Geologic CO{sub 2} Storage Infrastructure along Arches Province of the Midwest United States. The Arches Simulation project was a three year effort designed to develop a simulation framework for regional geologic carbon dioxide (CO{sub 2}) storage infrastructure along the Arches Province through development of a geologic model and advanced reservoir simulations of large-scale CO{sub 2} storage. The project included five major technical tasks: (1) compilation of geologic, hydraulic and injection data on Mount Simon, (2) development of model framework and parameters, (3) preliminary variable density flow simulations, (4) multi-phase model runs of regional storage scenarios, and (5) implications for regional storage feasibility. The Arches Province is an informal region in northeastern Indiana, northern Kentucky, western Ohio, and southern Michigan where sedimentary rock formations form broad arch and platform structures. In the province, the Mount Simon sandstone is an appealing deep saline formation for CO{sub 2} storage because of the intersection of reservoir thickness and permeability. Many CO{sub 2} sources are located in proximity to the Arches Province, and the area is adjacent to coal fired power plants along the Ohio River Valley corridor. Geophysical well logs, rock samples, drilling logs, and geotechnical tests were evaluated for a 500,000 km{sup 2} study area centered on the Arches Province. Hydraulic parameters and historical operational information was also compiled from Mount Simon wastewater injection wells in the region. This information was integrated into a geocellular model that depicts the parameters and conditions in a numerical array. The geologic and hydraulic data were integrated into a three-dimensional grid of porosity and permeability, which are key parameters regarding fluid flow and pressure buildup due to CO{sub 2} injection. Permeability data were corrected in locations where reservoir tests have been performed in Mount Simon injection wells. The geocellular model was used to develop a series of numerical simulations designed to support CO2 storage applications in the Arches Province. Variable density fluid flow simulations were initially run to evaluate model sensitivity to input parameters. Two dimensional, multiple-phase simulations were completed to evaluate issues related to arranging injection fields in the study area. A basin-scale, multiple-phase model was developed to evaluate large scale injection effects across the region. Finally, local scale simulations were also completed with more detailed depiction of the Eau Claire formation to investigate to the potential for upward migration of CO2. Overall, the technical work on the project concluded that injection large-scale injection may be achieved with proper field design, operation, siting, and monitoring. Records from Mount Simon injection wells were compiled, documenting more than 20 billion gallons of injection into the Mount Simon formation in the Arches Province over the past 40 years, equivalent to approximately 60 million metric tons CO2. The multi-state team effort was useful in delineating the geographic variability in the Mount Simon reservoir properties. Simulations better defined potential well fields, well field arrangement, CO2 pipeline distribution system, and operational parameters for large-scale injection in the Arches Province. Multiphase scoping level simulations suggest that injection fields with arrays of 9 to 50+ wells may be used to accommodate large injection volumes. Individual wells may need to be separated by 3 to 10 km. Injection fields may require spacing of 25 to 40 km to limit pressure and saturation front interference. Basin-scale multiple-phase simulations in STOMP reflect variability in the Mount Simon. While simulations suggest a total injection rate of 100 million metric tons per year (approximately to a 40% reduction of CO2 emissions from large point sources across the Arches Province) may be feasible, some areas are more suitable due to favorable geology. Sustainable injection rates were higher in areas where there was higher thickness and reservoir permeability. Distribution of injection across well fields is an effective method to reduce pressure and CO2 saturation front interference.

  8. On an improved sub-regional water resources management representation for integration into earth system models

    SciTech Connect (OSTI)

    Voisin, Nathalie; Li, Hongyi; Ward, Duane L.; Huang, Maoyi; Wigmosta, Mark S.; Leung, Lai-Yung R.

    2013-09-30

    Human influence on the hydrologic cycle includes regulation and storage, consumptive use and overall redistribution of water resources in space and time. Representing these processes is essential for applications of earth system models in hydrologic and climate predictions, as well as impact studies at regional to global scales. Emerging large-scale research reservoir models use generic operating rules that are flexible for coupling with earth system models. Those generic operating rules have been successful in reproducing the overall regulated flow at large basin scales. This study investigates the uncertainties of the reservoir models from different implementations of the generic operating rules using the complex multi-objective Columbia River Regulation System in northwestern United States as an example to understand their effects on not only regulated flow but also reservoir storage and fraction of the demand that is met. Numerical experiments are designed to test new generic operating rules that combine storage and releases targets for multi-purpose reservoirs and to compare the use of reservoir usage priorities, withdrawals vs. consumptive demand, as well as natural vs. regulated mean flow for calibrating operating rules. Overall the best performing implementation is the use of the combined priorities (flood control storage targets and irrigation release targets) operating rules calibrated with mean annual natural flow and mean monthly withdrawals. The challenge of not accounting for groundwater withdrawals, or on the contrary, assuming that all remaining demand is met through groundwater extractions, is discussed.

  9. Estimates of global, regional, and national annual CO{sub 2} emissions from fossil-fuel burning, hydraulic cement production, and gas flaring: 1950--1992

    SciTech Connect (OSTI)

    Boden, T.A.; Marland, G.; Andres, R.J.

    1995-12-01

    This document describes the compilation, content, and format of the most comprehensive C0{sub 2}-emissions database currently available. The database includes global, regional, and national annual estimates of C0{sub 2} emissions resulting from fossil-fuel burning, cement manufacturing, and gas flaring in oil fields for 1950--92 as well as the energy production, consumption, and trade data used for these estimates. The methods of Marland and Rotty (1983) are used to calculate these emission estimates. For the first time, the methods and data used to calculate CO, emissions from gas flaring are presented. This C0{sub 2}-emissions database is useful for carbon-cycle research, provides estimates of the rate at which fossil-fuel combustion has released C0{sub 2} to the atmosphere, and offers baseline estimates for those countries compiling 1990 C0{sub 2}-emissions inventories.

  10. Hybrid radiosity-SP{sub 3} equation based bioluminescence tomography reconstruction for turbid medium with low- and non-scattering regions

    SciTech Connect (OSTI)

    Chen, Xueli E-mail: jimleung@mail.xidian.edu.cn; Zhang, Qitan; Yang, Defu; Liang, Jimin E-mail: jimleung@mail.xidian.edu.cn

    2014-01-14

    To provide an ideal solution for a specific problem of gastric cancer detection in which low-scattering regions simultaneously existed with both the non- and high-scattering regions, a novel hybrid radiosity-SP{sub 3} equation based reconstruction algorithm for bioluminescence tomography was proposed in this paper. In the algorithm, the third-order simplified spherical harmonics approximation (SP{sub 3}) was combined with the radiosity equation to describe the bioluminescent light propagation in tissues, which provided acceptable accuracy for the turbid medium with both low- and non-scattering regions. The performance of the algorithm was evaluated with digital mouse based simulations and a gastric cancer-bearing mouse based in situ experiment. Primary results demonstrated the feasibility and superiority of the proposed algorithm for the turbid medium with low- and non-scattering regions.

  11. Grain size dependent phase stabilities and presence of a monoclinic (Pm) phase in the morphotropic phase boundary region of (1?x)Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} piezoceramics

    SciTech Connect (OSTI)

    Upadhyay, Ashutosh; Singh, Akhilesh Kumar E-mail: aksingh.mst@itbhu.ac.in

    2015-04-14

    Results of the room temperature structural studies on (1?x)Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} ceramics using Rietveld analysis of the powder x-ray diffraction data in the composition range 0.28???x???0.45 are presented. The morphotropic phase boundary region exhibits coexistence of monoclinic (space group Pm) and tetragonal (space group P4?mm) phases in the composition range 0.33???x???0.40. The structure is nearly single phase monoclinic (space group Pm) in the composition range 0.28???x???0.32. The structure for the compositions with x???0.45 is found to be predominantly tetragonal with space group P4?mm. Rietveld refinement of the structure rules out the coexistence of rhombohedral and tetragonal phases in the morphotropic phase boundary region reported by earlier authors. The Rietveld structure analysis for the sample x?=?.35 calcined at various temperatures reveals that phase fraction of the coexisting phases in the morphotropic phase boundary region varies with grain size. The structural parameters of the two coexisting phases also change slightly with changing grain size.

  12. Preparation and spectroscopic properties of rare-earth (RE) (RE = Sm, Eu, Tb, Dy, Tm)-activated K{sub 2}LnZr(PO{sub 4}){sub 3} (Ln = Y, La, Gd and Lu) phosphate in vacuum ultraviolet region

    SciTech Connect (OSTI)

    Zhang, Zhi-Jun; Lin, Xiao; Graduate School of Chinese Academy of Science, Beijing, 100039 ; Zhao, Jing-Tai; Zhang, Guo-Bin

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ? We report the VUV spectroscopic properties of rare-earth ions in K{sub 2}LnZr(PO{sub 4}){sub 3}. ? The O{sup 2?}-Eu{sup 3+} charge transfer bands at about 220 nm have been observed. ? The 4f5d spin-allowed and spin-forbidden transitions of Tb{sup 3+} have been observed. ? There is energy transfer between the host and rare-earth activators. -- Abstract: Rare earth (RE = Sm, Eu, Tb, Dy and Tm)-activated K{sub 2}LnZr(PO{sub 4}){sub 3} (Ln = Y, La, Gd and Lu) have been synthesized by solid-state reaction method, and their vacuum ultraviolet (VUV) excitation luminescent characteristics have been investigated. The band in the wavelength range of 130157 nm and the other one range from 155 to 216 nm with the maximum at about 187 nm in the VUV excitation spectra of these compounds are attributed to the host lattice absorption and OZr charge transfer transition, respectively. The charge transfer bands (CTB) of O{sup 2?}-Sm{sup 3+}, O{sup 2?}-Dy{sup 3+} and O{sup 2?}-Tm{sup 3+}, in Sm{sup 3+}, Dy{sup 3+} and Tm{sup 3+}-activated samples, have not been obviously observed probably because the 2p electrons of oxygen are tightly bound to the zirconium ion in the host lattice. For Eu{sup 3+}-activated samples, the relatively weak O{sup 2?}-Eu{sup 3+} CTB at about 220 nm is observed. And for Tb{sup 3+}-activated samples, the bands at 223 and 258 nm are related to the 4f-5d spin-allowed and spin-forbidden transitions of Tb{sup 3+}, respectively. It is observed that there is energy transfer between the host lattice and the luminescent activators (e.g. Eu{sup 3+}, Tb{sup 3+}). From the standpoint of luminescent efficiency, color purity and chemical stability, K{sub 2}GdZr(PO{sub 4}){sub 3}:Sm{sup 3+}, Eu{sup 3+}, Tb{sup 3+} are attractive candidates for novel yellow, red, green-emitting PDP phosphors.

  13. CO{sub 2} Allowance Allocation in the Regional Greenhouse Gas Initiative and the Effect on Electricity Investors

    SciTech Connect (OSTI)

    Burtraw, Dallas; Kahn, Danny; Palmer, Karen

    2006-03-01

    The Regional Greenhouse Gas Initiative among Northeastern states is expected to lead to an increase in the price of electricity in the region and beyond. In the RGGI region, changes in the value of electricity-generating assets may be positive or negative, while changes outside the Northeast are virtually always positive. For stakeholders in the industry, the change depends on the portfolio of assets held by affected firms. (author)

  14. Alkali-metal/alkaline-earth-metal fluorine beryllium borate NaSr{sub 3}Be{sub 3}B{sub 3}O{sub 9}F{sub 4} with large nonlinear optical properties in the deep-ultraviolet region

    SciTech Connect (OSTI)

    Reshak, A. H.; Huang, Hongwei; Kamarudin, H.; Auluck, S.

    2015-02-28

    The linear optical response and second harmonic generation (SHG) in alkali-metal/alkaline-earth-metal fluorine beryllium borate NaSr{sub 3}Be{sub 3}B{sub 3}O{sub 9}F{sub 4} are investigated by means of density functional theory. Calculations are performed using four types of exchange correlations: Ceperley-Alder local density approximation, Perdew Burke and Ernzerhof general gradient approximation, Engel-Vosko generalized gradient approximation, and the recently modified Becke-Johnson potential (mBJ). The mBJ approach brings the calculated band gap (7.20 eV) in excellent agreement with the experimental one (7.28 eV). The calculated values of the uniaxial anisotropy δε=−0.076 and the birefringence Δn(0)=0.052 indicate considerable anisotropy in the linear optical properties, which makes it favorable for the second harmonic generation. The dominant component of the second harmonic generation is χ{sub 111}{sup (2)}(ω). The value of |χ{sub 111}{sup (2)}(ω)| is about 1.2 pm/V at λ = 1064 nm in agreement with previous calculations. To analyze the origin of the high SHG of NaSr{sub 3}Be{sub 3}B{sub 3}O{sub 9}F{sub 4} single crystals, we have correlated the features of |χ{sub 111}{sup (2)}(ω)| spectra with the features of ε{sub 2}(ω) spectra as a function of ω/2 and ω. From the calculated dominant component |χ{sub 111}{sup (2)}(ω)|, we find that the microscopic first hyperpolarizability, β{sub 111}, the vector components along the dipole moment direction is 0.5 × 10{sup −30} esu at static limit and 0.6 × 10{sup −30} esu at λ = 1064 nm.

  15. Conceptual Model Summary Report Simulation Framework for Regional Geologic CO{sub 2} Storage Along Arches Province of Midwestern United States

    SciTech Connect (OSTI)

    2011-06-30

    A conceptual model was developed for the Arches Province that integrates geologic and hydrologic information on the Eau Claire and Mt. Simon formations into a geocellular model. The conceptual model describes the geologic setting, stratigraphy, geologic structures, hydrologic features, and distribution of key hydraulic parameters. The conceptual model is focused on the Mt. Simon sandstone and Eau Claire formations. The geocellular model depicts the parameters and conditions in a numerical array that may be imported into the numerical simulations of carbon dioxide (CO{sub 2}) storage. Geophysical well logs, rock samples, drilling logs, geotechnical test results, and reservoir tests were evaluated for a 500,000 km{sup 2} study area centered on the Arches Province. The geologic and hydraulic data were integrated into a three-dimensional (3D) grid of porosity and permeability, which are key parameters regarding fluid flow and pressure buildup due to CO{sub 2} injection. Permeability data were corrected in locations where reservoir tests have been performed in Mt. Simon injection wells. The final geocellular model covers an area of 600 km by 600 km centered on the Arches Province. The geocellular model includes a total of 24,500,000 cells representing estimated porosity and permeability distribution. CO{sub 2} injection scenarios were developed for on-site and regional injection fields at rates of 70 to 140 million metric tons per year.

  16. Critical interpretation of CH and OH stretching regions for infrared spectra of methanol clusters (CH{sub 3}OH){sub n} (n = 25) using self-consistent-charge density functional tight-binding molecular dynamics simulations

    SciTech Connect (OSTI)

    Nishimura, Yoshifumi; Lee, Yuan-Pern; Irle, Stephan; Witek, Henryk A.

    2014-09-07

    Vibrational infrared (IR) spectra of gas-phase OH???O methanol clusters up to pentamer are simulated using self-consistent-charge density functional tight-binding method using two distinct methodologies: standard normal mode analysis and Fourier transform of the dipole time-correlation function. The twofold simulations aim at the direct critical assignment of the CH stretching region of the recently recorded experimental spectra [H.-L. Han, C. Camacho, H. A. Witek, and Y.-P. Lee, J. Chem. Phys. 134, 144309 (2011)]. Both approaches confirm the previous assignment (ibid.) of the CH stretching bands based on the B3LYP/ANO1 harmonic frequencies, showing that ?{sub 3}, ?{sub 9}, and ?{sub 2} CH stretching modes of the proton-accepting (PA) and proton-donating (PD) methanol monomers experience only small splittings upon the cluster formation. This finding is in sharp discord with the assignment based on anharmonic B3LYP/VPT2/ANO1 vibrational frequencies (ibid.), suggesting that some procedural faults, likely related to the breakdown of the perturbational vibrational treatment, led the anharmonic calculations astray. The IR spectra based on the Fourier transform of the dipole time-correlation function include new, previously unaccounted for physical factors such as non-zero temperature of the system and large amplitude motions of the clusters. The elevation of temperature results in a considerable non-homogeneous broadening of the observed IR signals, while the presence of large-amplitude motions (methyl group rotations and PA-PD flipping), somewhat surprisingly, does not introduce any new features in the spectrum.

  17. Measurement of astrophysical S factors and electron screening potentials for d(d, n){sup 3}He reaction In ZrD{sub 2}, TiD{sub 2}, D{sub 2}O, and CD{sub 2} targets in the ultralow energy region using plasma accelerators

    SciTech Connect (OSTI)

    Bystritsky, V. M.; Bystritskii, Vit. M.; Dudkin, G. N.; Filipowicz, M.; Gazi, S.; Huran, J.; Kobzev, A. P.; Mesyats, G. A.; Nechaev, B. A.; Padalko, V. N.; Parzhitskii, S. S.; Pen'kov, F. M.; Philippov, A. V.; Kaminskii, V. L.; Tuleushev, Yu. Zh.; Wozniak, J.

    2012-01-15

    The paper is devoted to study electron screening effect influence on the rate of d(d, n){sup 3}He reaction in the ultralow deuteron collision energy range in the deuterated polyethylene (CD{sub 2}), frozen heavy water (D{sub 2}O) and deuterated metals (ZrD{sub 2} and TiD{sub 2}). The ZrD{sub 2} and TiD{sub 2} targets were fabricated via magnetron sputtering of titanium and zirconium in gas (deuterium) environment. The experiments have been carried out using high-current plasma pulsed accelerator with forming of inverse Z pinch (HCEIRAS, Russia) and pulsed Hall plasma accelerator (NPI at TPU, Russia). The detection of neutrons with energy of 2.5MeV from dd reaction was done with plastic scintillation spectrometers. As a result of the experiments the energy dependences of astrophysical S factor for the dd reaction in the deuteron collision energy range of 2-7 keV and the values of the electron screening potential U{sub e} of interacting deuterons have been measured for the indicated above target: U{sub e}(CD{sub 2}) Less-Than-Or-Slanted-Equal-To 40 eV; U{sub e}(D{sub 2}O) Less-Than-Or-Slanted-Equal-To 26 eV; U{sub e}(ZrD{sub 2}) = 157 {+-} 43 eV; U{sub e}(TiD{sub 2}) = 125{+-}34 eV. The value of astrophysical S factor, corresponding to the deuteron collision energy equal to zero, in the experiments with D{sub 2}O target is found: S{sub b}(0) = 58.6 {+-} 3.6 keV b. The paper compares our results with other available published experimental and calculated data.

  18. Wireless System Considerations When Implementing NERC Critical...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    More Documents & Publications Recommended Practices Guide For Securing ZigBee Wireless Networks in Process Control System Environments Securing WLANs using 802.11i DOEOE National ...

  19. NERC_Interconnection_1A.pdf

    Energy Savers [EERE]

  20. schedule6_2002.xls

    U.S. Energy Information Administration (EIA) Indexed Site

    Next Update: October 2008 Table 6. Existing and Proposed High-voltage Transmission Line Additions Filed in Calendar Year 2002, by North American Electric Reliability Council, 2003 Through 20012 (Various) Geographic Area Voltage Capacity Rating (MVa) In- Service Date Electrical Connection Locations Line Information Conductor Characteristics Circuits Company Information Country NERC Region NERC Sub-region Type Operating (kV) Design (kV) From Terminal To Terminal Length (Miles) Type Pole Type Pole

  1. ,"Geographic Area",,,"Voltage",,,"Capacity Rating (MVa)","In-Service Date","Electrical Connection Locations",,"Line Information",,,,"Conductor Characteristics",,,"Circuits",,"Company Information"

    U.S. Energy Information Administration (EIA) Indexed Site

    Covering Calendar Year 2005, by North American Electric Reliability Council, 2006 Through 2011" ,"(Various)" ,"Geographic Area",,,"Voltage",,,"Capacity Rating (MVa)","In-Service Date","Electrical Connection Locations",,"Line Information",,,,"Conductor Characteristics",,,"Circuits",,"Company Information" ,"Country - with Total (T) for sub-regions","NERC Region"," NERC

  2. Insight into the Atomic Structure of High-Voltage Spinel LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> Cathode Material in the First Cycle

    SciTech Connect (OSTI)

    Huang, Xuejie; Yu, Xiqian; Lin, Mingxiang; Ben, Liubin; Sun, Yang; Wang, Hao; Yang, Zhenzhong; Gu, Lin; Yang, Xiao -Qing; Zhao, Haofei; Yu, Richeng; Armand, Michel

    2014-12-22

    Application of high-voltage spinel LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> cathode material is the closest and the most realistic approach to meeting the midterm goal of lithium-ion batteries for electric vehicles (EVs) and plug-in hybrid electric vehicles (HEVs). However, this application has been hampered by long-standing issues, such as capacity degradation and poor first-cycle Coulombic efficiency of LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> cathode material. Although it is well-known that the structure of LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> into which Li ions are reversibly intercalated plays a critical role in the above issues, performance degradation related to structural changes, particularly in the first cycle, are not fully understood. Here, we report detailed investigations of local atomic-level and average structure of LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> during first cycle (3.5–4.9 V) at room temperature. We observed two types of local atomic-level migration of transition metals (TM) ions in the cathode of a well-prepared LiNi<sub>0.5sub>Mn>1.5sub>O>4sub>//Li half-cell during first charge via an aberration-corrected scanning transmission electron microscopy (STEM). Surface regions (~2 nm) of the cycled LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> particles show migration of TM ions into tetrahedral Li sites to form a Mn<sub>3sub>O>4sub>-like structure. However, subsurface regions of the cycled particles exhibit migration of TM ions into empty octahedral sites to form a rocksalt-like structure. The migration of these TM ions are closely related to dissolution of Ni/Mn ions and building-up of charge transfer impedance, which contribute significantly to the capacity degradation and the poor first-cycle Coulombic efficiency of spinel LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> cathode material. Accordingly, we provide suggestions of effective stabilization of LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> structure to obtain better electrochemical performance.

  3. Insight into the Atomic Structure of High-Voltage Spinel LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> Cathode Material in the First Cycle

    SciTech Connect (OSTI)

    Huang, Xuejie; Yu, Xiqian; Lin, Mingxiang; Ben, Liubin; Sun, Yang; Wang, Hao; Yang, Zhenzhong; Gu, Lin; Yang, Xiao -Qing; Zhao, Haofei; Yu, Richeng; Armand, Michel

    2014-12-22

    Application of high-voltage spinel LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> cathode material is the closest and the most realistic approach to meeting the midterm goal of lithium-ion batteries for electric vehicles (EVs) and plug-in hybrid electric vehicles (HEVs). However, this application has been hampered by long-standing issues, such as capacity degradation and poor first-cycle Coulombic efficiency of LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> cathode material. Although it is well-known that the structure of LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> into which Li ions are reversibly intercalated plays a critical role in the above issues, performance degradation related to structural changes, particularly in the first cycle, are not fully understood. Here, we report detailed investigations of local atomic-level and average structure of LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> during first cycle (3.54.9 V) at room temperature. We observed two types of local atomic-level migration of transition metals (TM) ions in the cathode of a well-prepared LiNi<sub>0.5sub>Mn>1.5sub>O>4sub>//Li half-cell during first charge via an aberration-corrected scanning transmission electron microscopy (STEM). Surface regions (~2 nm) of the cycled LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> particles show migration of TM ions into tetrahedral Li sites to form a Mn<sub>3sub>O>4sub>-like structure. However, subsurface regions of the cycled particles exhibit migration of TM ions into empty octahedral sites to form a rocksalt-like structure. The migration of these TM ions are closely related to dissolution of Ni/Mn ions and building-up of charge transfer impedance, which contribute significantly to the capacity degradation and the poor first-cycle Coulombic efficiency of spinel LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> cathode material. Accordingly, we provide suggestions of effective stabilization of LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> structure to obtain better electrochemical performance.

  4. Synthesis, structure, and physical properties of [Sm(C{sub 6}NO{sub 2}H{sub 5}){sub 3}(H{sub 2}O){sub 2}]{sub 2n}.(H{sub 5}O{sub 2}){sub n}(ZnCl{sub 5}){sub n}(ZnCl{sub 4}){sub 2n}.(H{sub 2}O){sub 2n} with unprecedented ZnCl{sub 5}{sup 3-} species

    SciTech Connect (OSTI)

    Xie Yiming Chen Wentong; Wu Jihuai

    2008-08-15

    A novel bimetallic 4f-3d metal-isonicotinic acid inorganic-organic hybrid complex [Sm(C{sub 6}NO{sub 2}H{sub 5}){sub 3}(H{sub 2}O){sub 2}]{sub 2n}.(H{sub 5}O{sub 2}){sub n}(ZnCl{sub 5}){sub n}(ZnCl{sub 4}){sub 2n}.(H{sub 2}O){sub 2n} (1) has been synthesized via hydrothermal reaction and structurally characterized by single-crystal X-ray diffraction. Complex 1 is characteristic of a one-dimensional polycationic chain-like structure and unprecedented ZnCl{sub 5}{sup 3-} species. Photoluminescent investigation reveals that the title complex displays interesting emissions in a wide region. Optical absorption spectra of 1 reveal the presence of an optical gap of 3.59 eV. - Graphical abstract: A novel bimetallic 4f-3d metal-isonicotinic acid inorganic-organic hybrid complex was synthesized. It is characteristic of a one-dimensional polycationic chain-like structure. Photoluminescent investigation reveals that the title complex displays interesting emissions in a wide region. Optical absorption spectra of 1 reveal the presence of a wide optical bandgap.

  5. Specific heat investigation for line nodes in heavily overdoped Ba<sub>1-xsub>KxFe>2sub>As>2sub>

    SciTech Connect (OSTI)

    Kim, J. S.; Stewart, G. R.; Liu, Yong; Lograsso, Thomas A.

    2015-06-10

    Previous research has found that the pairing symmetry in the iron-based superconductor Ba<sub>1-xsub>KxFe>2sub>As>2sub> changes from nodeless s-wave near optimally doped, x?0.4-0.55 and T<sub>c>>30 K, to nodal (either d-wave or s-wave) at the pure endpoint, x=1 and T<sub>c><4 K. Intense theoretical interest has been focused on this possibility of changing pairing symmetry, where in the transition region both order parameters would be present and time reversal symmetry would be broken. Here we report specific heat measurements in zero and applied magnetic fields down to 0.4 K of three individual single crystals, free of low temperature magnetic anomalies, of heavily overdoped Ba<sub>1-xsub>KxFe>2sub>As>2sub>, x= 0.91, 0.88, and 0.81. The values for T<sub>c>mid are 5.6, 7.2 and 13 K and for H<sub>c2sub>? 4.5, 6, and 20 T respectively. Furthermore, the data can be analyzed in a two gap scenario, ?<sub>2sub>/?>1sub> ? 4, with the magnetic field dependence of ? (=C/T as T?0) showing an anisotropic S-shaped behavior vs H, with the suppression of the lower gap by 1 T and ? ? H1/2 overall. Although such a non-linear ? vs H is consistent with deep minima or nodes in the gap structure, it is not clear evidence for one, or both, of the gaps being nodal in these overdoped samples. Thus, following the established theoretical analysis of the specific heat of d-wave cuprate superconductors containing line nodes, we present the specific heat normalized by H1/2 plotted vs T/H1/2 of these heavily overdoped Ba<sub>1-xsub>KxFe>2sub>As>2sub> samples which thanks to the absence of magnetic impurities in our sample - convincingly shows the expected scaling for line node behavior for the larger gap for all three compositions. There is however no clear observation of the nodal behavior C ? ?T2 in zero field at low temperatures, with ? ? 2 mJ/molK3 being consistent with the data. Together with the scaling, this leaves open the possibility of extreme anisotropy in a nodeless larger gap, ?<sub>2sub>, such that the scaling works for fields above 0.25 0.5 T (0.2 0.4 K in temperature units), where this an estimate for the size of the deep minima in the ?<sub>2sub> ~ 20-25 K gap. Furthermore, the location of the change from nodeless?nodal gaps between optimally doped and heavily overdoped Ba<sub>1-xsub>KxFe>2sub>As>2sub> based on the present work may be closer to the KFe<sub>2sub>As>2sub> endpoint than x=0.91.

  6. Influence of valence electron concentration on Laves phases: Structures and phase stability of pseudo-binary MgZn<sub>2-xsub>Pdx>

    SciTech Connect (OSTI)

    Thimmaiah, Srinivasa; Miller, Gordon J.

    2015-06-03

    A series of pseudo-binary compounds MgZn<sub>2-xsub>Pdx> (0.15 ? x ? 1.0) were synthesized and structurally characterized to understand the role of valence electron concentration (vec) on the prototype Laves phase MgZn<sub>2sub> with Pd-substitution. Three distinctive phase regions were observed with respect to Pd content, all exhibiting fundamental Laves phase structures: 0.1 ? x ? 0.3 (MgNi<sub>2sub>-type, hP24; MgZn<sub>1.80sub>Pd>0.20(2)sub>), 0.4 ? x ? 0.6 (MgCu<sub>2sub>-type, cF24; MgZn<sub>1.59sub>Pd>0.41(2)sub>), and 0.62 ? x ? 0.8 (MgZn<sub>2sub>-type, hP12: MgZn<sub>1.37sub>Pd>0.63(2)sub>). Refinements from single-crystal X-ray diffraction indicated nearly statistical distributions of Pd and Zn atoms among the majority atom sites in these structures. Interestingly, the MgZn<sub>2sub>-type structure re-emerges in MgZn<sub>2xsub>Pdx> at x ? 0.7 with the refined composition MgZn<sub>1.37(2)sub>Pd>0.63sub> and a c/a ratio of 1.59 compared to 1.64 for binary MgZn<sub>2sub>. Electronic structure calculations on a model MgZn<sub>1.25sub>Pd>0.75sub> yielded a density of states (DOS) curve showing enhancement of a pseudogap at the Fermi level as a result of electronic stabilization due to the Pd addition. Moreover, integrated crystal orbital Hamilton population values show significant increases of orbital interactions for (Zn,Pd)(Zn,Pd) atom pairs within the majority atom substructure, i.e., within the Kagom nets as well as between a Kagom net and an apical site, from binary MgZn<sub>2sub> to the ternary MgZn<sub>1.25sub>Pd>0.75sub>. Multi-centered bonding is evident from electron localization function plots for MgZn<sub>1.25sub>Pd>0.75sub>, an outcome which is in accordance with analysis of other Laves phases.

  7. Oxygen vacancy migration in disordered Gd{sub 2}(Zr{sub x}Ti{sub 1{minus}x}){sub 2}O{sub 7}

    SciTech Connect (OSTI)

    Williford, R.E.; Weber, W.J.; Devanathan, R.; Gale, J.D.

    1999-07-01

    Oxygen vacancy formation and migration energies in the pyrochlores Gd{sub 2}(Zr{sub x}Ti{sub 1{minus}x}){sub 2}O{sub 7} were computed using atomistic energy minimization methods, with particular attention to the role of cation antisite disorder. The interatomic potentials recognize oxygens in distinct crystallographic sites (polarizations) as distinct species, and permit assessment of the directional anisotropy in vacancy migration energies. Oxygen vacancy migration is determined by O{sub 48f} {minus} O{sub 48f} transitions along the shortest edges of the TiO{sub 6} octahedra, in agreement with previous results. Oxygen vacancies migrate towards disorder to reduce local stresses. In contrast to previous work, the V{sub 08a} and V{sub O8a} + I{sub O8b} Frenkel defects are favored over the V{sub O48f} and V{sub O48f} + I{sub O8b} Frenkel. The transition V{sub O8a}{minus}> V{sub O48f} is energetically favored for the ordered structure, and activates the three dimensional O{sub 48f} {minus} O{sub 48f} vacancy migration network by filling empty 9a sites with 48f oxygens. Local regions of order and moderate disorder must both be present for optimum oxygen conductivity. High disorder retards vacancy migration.

  8. CO{sub 2} Sequestration Capacity and Associated Aspects of the Most Promising Geologic Formations in the Rocky Mountain Region: Local-Scale Analyses

    SciTech Connect (OSTI)

    Laes, Denise; Eisinger, Chris; Morgan, Craig; Rauzi, Steve; Scholle, Dana; Scott, Phyllis; Lee, Si-Yong; Zaluski, Wade; Esser, Richard; Matthews, Vince; McPherson, Brian

    2013-07-30

    The purpose of this report is to provide a summary of individual local-­‐scale CCS site characterization studies conducted in Colorado, New Mexico and Utah. These site-­‐ specific characterization analyses were performed as part of the “Characterization of Most Promising Sequestration Formations in the Rocky Mountain Region” (RMCCS) project. The primary objective of these local-­‐scale analyses is to provide a basis for regional-­‐scale characterization efforts within each state. Specifically, limits on time and funding will typically inhibit CCS projects from conducting high-­‐ resolution characterization of a state-­‐sized region, but smaller (< 10,000 km{sup 2}) site analyses are usually possible, and such can provide insight regarding limiting factors for the regional-­‐scale geology. For the RMCCS project, the outcomes of these local-­‐scale studies provide a starting point for future local-­‐scale site characterization efforts in the Rocky Mountain region.

  9. Evidence for tt?? Production and Measurement of (?<sub> tt?sub>)?/(?tt?>)

    SciTech Connect (OSTI)

    Aaltonen, T; Alvarez Gonzalez, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Apresyan, A; Arisawa, T

    2011-08-31

    Using data corresponding to 6.0 fb-1 of pp? collisions at ?s = 1.96 TeV collected by the CDF II detector, we present a cross section measurement of top-quark pair production with an additional radiated photon, tt??. The events are selected by looking for a lepton (ell), a photon (?), significant transverse momentum imbalance (E<sub>T>), large total transverse energy, and three or more jets, with at least one identified as containing a b quark (b). The tt?? sample requires the photon to have 10 GeV or more of transverse energy, and to be in the central region. Using an event selection optimized for the tt?? candidate sample we measure the production cross section of tt? (?<sub>tt?>), and the ratio of cross sections of the two samples. Control samples in the dilepton+photon and lepton+photon+E<sub>T>, channels are constructed to aid in decay product identification and background measurements. We observe 30 tt?? candidate events compared to the standard model expectation of 26.9 3.4 events. We measure the tt?? cross section (?<sub>tt?>) to be 0.18 0.08 pb, and the ratio of ?<sub>tt?>? to ?<sub>tt?> to be 0.024 0.009. Assuming no tt?? production, we observe a probability of 0.0015 of the background events alone producing 30 events or more, corresponding to 3.0 standard deviations.

  10. To: Regional Managers

    Energy Savers [EERE]

    N O R T H A M E R I C A N E L E C T R I C R E L I A B I L I T Y C O U N C I L P r i n c e t o n F o r r e s t a l V i l l a g e , 1 1 6 - 3 9 0 V i l l a g e B o u l e v a r d , P r i n c e t o n , N e w J e r s e y 0 8 5 4 0 - 5 7 3 1 Phone 609-452-8060 Fax 609-452-9550 URL www.nerc.com FOR IMMEDIATE RELEASE Contact: Ellen P. Vancko evancko@nerc.com Preliminary Disturbance Report August 14, 2003 Sequence of Events The following information represents a partial sequence of events based upon

  11. Remarkably robust and correlated coherence and antiferromagnetism in (Ce<sub>1-xsub>Lax)Cu>2sub>Ge>2sub>

    SciTech Connect (OSTI)

    Hodovanets, H.; Budko, S. L.; Straszheim, W. E.; Taufour, V.; Mun, E. D.; Kim, H.; Flint, R.; Canfield, P. C.

    2015-06-08

    We present magnetic susceptibility, resistivity, specific heat, and thermoelectric power measurements on (Ce<sub>1-xsub>Lax)Cu>2sub>Ge>2sub> single crystals (0 ? x ? 1). With La-substitution, the antiferromagnetic temperature T<sub>N> is suppressed in an almost linear fashion and moves below 0.36 K, the base temperature of our measurements for x > 0.8. Surprisingly, in addition to robust antiferromagnetism, the system also shows low temperature coherent scattering below T<sub>coh> up to ~0.9 of La, indicating a small percolation limit ~9% of Ce. T<sub>coh> as a function of magnetic field was found to have different behavior for x < 0.9 and x > 0.9. Remarkably, (T<sub>coh>)2 at H = 0 was found to be linearly proportional to T<sub>N>. In conclusion, the jump in the magnetic specific heat ?C<sub>m> at T<sub>N> as a function of T<sub>K/TN> for (Ce<sub>1-xsub>Lax)Cu>2sub>Ge>2sub> follows the theoretical prediction based on the molecular field calculation for the S = 1/2 resonant level model.

  12. Development of very high J<sub>c> in Ba(Fe<sub>1-xsub>Cox)>2sub>As>2sub> thin films grown on CaF<sub>2sub>

    SciTech Connect (OSTI)

    Tarantini, C.; Kametani, F.; Lee, S.; Jiang, J.; Weiss, J. D.; Jaroszynski, J.; Hellstrom, E. E.; Eom, C. B.; Larbalestier, D. C.

    2014-12-03

    Ba(Fe<sub>1-xsub>Cox)>2sub>As>2sub> is the most tunable of the Fe-based superconductors (FBS) in terms of acceptance of high densities of self-assembled and artificially introduced pinning centres which are effective in significantly increasing the critical current density, J<sub>c>. Moreover, FBS are very sensitive to strain, which induces an important enhancement in critical temperature,T<sub>c>, of the material. In this study we demonstrate that strain induced by the substrate can further improve J<sub>c> of both single and multilayer films by more than that expected simply due to the increase in T<sub>c>. The multilayer deposition of Ba(Fe<sub>1-xsub>Cox)>2sub>As>2sub> on CaF<sub>2sub> increases the pinning force density (F<sub>p=Jc> x μ₀H) by more than 60% compared to a single layer film, reaching a maximum of 84 GN/m3 at 22.5 T and 4.2 K, the highest value ever reported in any 122 phase.

  13. Microsoft PowerPoint - ACOE Regional HydroPower Conference Presentation.ppt

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    HYDROPOWER CONFERENCE Tulsa, Oklahoma June 10 - 11, 2009 NERC Requirements for Generator Owner and Operator Sarah M. Blankenship, NERC Compliance Officer How do we create a culture that combines Processes, Policies and Procedures, PEOPLE and Technology? Development of an Internal NERC Compliance Program Applicable NERC Requirements for Functions GOP GO BAL-005-0 R1 CIP-001-1 R1R2 R3R4 (Sabotage Reporting) COM-002-2 R1(Communications) EOP-004-1 R2 R3 (Disturbance Reporting) Can be combined into

  14. Measurement of the Target-Normal Single-Spin Asymmetry A{sub y}{sup n} in the Deep Inelastic Region from the Reaction {sup 3}He{up_arrow}(e,e')

    SciTech Connect (OSTI)

    Katich, Joseph [William and Mary College

    2011-01-01

    A first measurement of the inclusive target single-spin asymmetry, A{sup n}{sub y}, has been performed in deep-inelastic scattering of electrons from a {sup 3}He target polarized normal to the electron scattering plane. This asymmetry is void of contributions at the Born level, and thus is a direct observable for two-photon physics. The experiment was performed in Hall A at Thomas Jefferson National Accelerator Facility from October 2008 through early February 2009. The measurement is the first from a polarized neutron target. The final overall precision is several times better than previously existing SLAC proton data, and significantly extends the kinematic range over which the asymmetry has been measured. The asymmetry was measured at five kinematic points in the deep inelastic scattering region covering Q{sup 2} = 1 - 3 GeV{sup 2} and x{sub B} = 0.16 to 0.41. The asymmetry varied from 0.006 to 0.071 with astatistical precision at the 10{sup -2} level.

  15. Electron motion in the gases CF/sub 4/, C/sub 2/F/sub 6/, C/sub 3/F/sub 8/, and n-C/sub 4/F/sub 10/

    SciTech Connect (OSTI)

    Hunter, S.R.; Carter, J.G.; Christophorou, L.G.

    1988-07-01

    The drift velocity w of electrons has been measured in the perfluoroalkanes n-C/sub N/F/sub 2//sub N//sub +2/ (N = 1--4) over the density-reduced electric field (E/N) range 0.03 x 10/sup -17/ V cm/sup 2/less than or equal toE/Nless than or equal to500 x 10/sup -17/ V cm/sup 2/ using a pulsed Townsend experimental method. The present measurements of w are the first to be obtained for C/sub 2/F/sub 6/, C/sub 3/F/sub 8/, and n-C/sub 4/F/sub 10/ at low E/N values. The electron-drift-velocity measurements in C/sub 3/F/sub 8/ and n-C/sub 4/F/sub 10/ are dependent on gas pressure at high E/N values, even after allowing for nonequilibrium and boundary corrections to the measured electron swarm transit time. This is the first observation of a pressure dependence in the electron drift velocity in these gases and is believed to be due to changes in the electron energy distribution function f(epsilon-c,E/N) with gas pressure resulting from increases in the density-normalized electron attachment coefficient eta/N with gas pressure. The perfluoroalkanes CF/sub 4/, C/sub 2/F/sub 6/, and C/sub 3/F/sub 8/ exhibit regions of pronounced negative differential conductivity (NDC) similar to but smaller in magnitude than that in CH/sub 4/. Possible mechanisms leading to the observation of NDC effects in these molecular gases are discussed.

  16. Li.sub.2 O-Al.sub.2 O.sub.3 -SiO.sub.2 glass ceramic-aluminum containing austenitic stainless steel composite body and a method of producing the same

    DOE Patents [OSTI]

    Cassidy, Roger T.

    1990-05-01

    The present invention relates to a hermetically sealed Li.sub.2 O-Al.sub.2 O.sub.3 -SiO.sub.2 glass ceramic-aluminum containing stainless steel composite body and a method of producing the body. The composite body includes an oxide interfacial region between the glass ceramic and metal, wherein the interfacial region consists essentially of an Al.sub.2 O.sub.3 layer. The interfacial Al.sub.2 O.sub.3 region includes constituents of both the metal and glass ceramic.

  17. Phase-diagram study for the Al{sub 2}O{sub 3}-CaF{sub 2}-SiO{sub 2} system

    SciTech Connect (OSTI)

    Ueda, Shigeru; Maeda, Masafumi

    1999-10-01

    Phase relations for the Al{sub 2}O{sub 3}-CaF{sub 2}-SiO{sub 2} system were investigated from 1,673 to 1,723 K. The hot-filament technique was applied to observe a two-liquid region and liquidus for the ternary system. The liquidus saturated with SiO{sub 2} was investigated at 1673 K by using the hot-filament technique and the chemical equilibrium technique. In this system, the addition of Al{sub 2}O{sub 3} to the CaF{sub 2}-SiO{sub 2} system reduces the congruent temperature. A small substitution of Al{sub 2}O{sub 3} for CaF{sub 2} increases the solubility of SiO{sub 2}, namely, if the region of liquid phase could be enlarged. These results suggest that Al{sub 2}O{sub 3} would be an effective substitute of CaF{sub 2} in slag for steelmaking.

  18. Structure symmetry determination and magnetic evolution in Sr<sub>2sub>Ir>1–xsub>RhxO>4sub>

    SciTech Connect (OSTI)

    Ye, Feng; Wang, Xiaoping; Hoffmann, Christina; Wang, Jinchen; Chi, Songxue; Matsuda, Masaaki; Chakoumakos, Bryan C.; Fernandez-Baca, Jaime A.; Cao, Gang

    2015-11-23

    We use single-crystal neutron diffraction to determine the crystal structure symmetry and to study the magnetic evolution in the rhodium doped iridates Sr<sub>2sub>Ir>1–xsub>RhxO>4sub> (0 ≤ x ≤ 0.16). Throughout this doping range, the crystal structure retains a tetragonal symmetry (space group I4<sub>1sub>/a) with two distinct magnetic Ir sites in the unit cell forming staggered IrO<sub>6sub> rotation. Upon Rh doping, the magnetic order is suppressed and the magnetic moment of Ir4+ is reduced from 0.21 μ<sub>B>/Ir for x = 0 to 0.18 μ<sub>B>/Ir for x = 0.12. As a result, the magnetic structure at x = 0.12 is different from that of the parent compound while the moments remain in the basal plane.

  19. Interfacial dislocations in (111) oriented (Ba<sub>0.7sub>Sr>0.3sub>)TiO>3sub> films on SrTiO<sub>3sub> single crystal

    SciTech Connect (OSTI)

    Shen, Xuan; Yamada, Tomoaki; Lin, Ruoqian; Kamo, Takafumi; Funakubo, Hiroshi; Wu, Di; Xin, Huolin L.; Su, Dong

    2015-10-08

    In this study, we have investigated the interfacial structure of epitaxial (Ba,Sr)TiO<sub>3sub> films grown on (111)-oriented SrTiO<sub>3sub> single-crystal substrates using transmission electron microscopy (TEM) techniques. Compared with the (100) epitaxial perovskite films, we observe dominant dislocation half-loop with Burgers vectors of a<110> comprised of a misfit dislocation along <112>, and threading dislocations along <110> or <100>. The misfit dislocation with Burgers vector of a <110> can dissociate into two ½ a <110> partial dislocations and one stacking fault. We found the dislocation reactions occur not only between misfit dislocations, but also between threading dislocations. Via three-dimensional electron tomography, we retrieved the configurations of the threading dislocation reactions. The reactions between threading dislocations lead to a more efficient strain relaxation than do the misfit dislocations alone in the near-interface region of the (111)-oriented (Ba<sub>0.7sub>Sr>0.3sub>)TiO>3sub> films.

  20. Agency Sub-

    Energy Savers [EERE]

    February 2015 Agency Sub- agency Title Of Initiative/Rule or ICR RIN/OMB Control Number Summary of Initiative Status of Initiative -- New to this update, Ongoing, or Completed Target Completion Date (if completed, please add the publication date and cite in Federal Register for example) Does the Initiative include regulatory flexibilities such as pilot projects, safe harbor exemptions, sunset provisions, trigger provisions, streamlined requirements, state flexibilities, or other similar

  1. Agency Sub-

    Energy Savers [EERE]

    July 2015 Agency Sub- agency Title Of Initiative/Rule or ICR RIN/OMB Control Number Summary of Initiative Status of Initiative -- New to this update, Ongoing, or Completed Target Completion Date (if completed, please add the publication date and cite in Federal Register for example) Does the Initiative include regulatory flexibilities such as pilot projects, safe harbor exemptions, sunset provisions, trigger provisions, streamlined requirements, state flexibilities, or other similar strategies?

  2. Agency Sub-

    Energy Savers [EERE]

    Report as of March 2016 Agency Sub- agency Title Of Initiative/Rule or ICR RIN/OMB Control Number Summary of Initiative Status of Initiative -- New to this update, Ongoing, or Completed Target Completion Date (if completed, please add the publication date and cite in Federal Register for example) Does the Initiative include regulatory flexibilities such as pilot projects, safe harbor exemptions, sunset provisions, trigger provisions, streamlined requirements, state flexibilities, or other

  3. NERC IVGTF Task 1-3 Section 3-1

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Home / National Environmental Policy Act (NEPA) NEPA Reading Room Welcome to the National Nuclear Security Administration's NEPA Reading Room. This site serves as a focal point for NNSA NEPA implementation and contains information about past and current NNSA NEPA actions as well as other resources for NEPA practitioners and members of the public. Welcome to the National Nuclear Security Administration's NEPA Reading Room. This site serves as a focal point for NNSA NEPA implementation and

  4. Property:EIA/861/NercMro | Open Energy Information

    Open Energy Info (EERE)

    + true + Brainerd Public Utilities + true + Brodhead Water & Lighting Comm + true + Brown County Rural Elec Assn + true + Burke-Divide Electric Coop Inc + true + Butler County...

  5. Property:EIA/861/NercSerc | Open Energy Information

    Open Energy Info (EERE)

    Electric Coop + true + Beauregard Electric Coop, Inc + true + Benton County + true + Berkeley Electric Coop Inc + true + (previous 25) (next 25) Retrieved from "http:...

  6. NERC standards and standards compliance: still a work in progress?

    SciTech Connect (OSTI)

    Lyons, Cristin; Jacobi, Jere; Starkweather, Rick

    2008-04-15

    The August 2003 blackout served as a wake-up call to all of North America. Several years of detailed assessment and planning by transmission governing bodies have provided a method of systematically improving the integrity of the transmission grid, but processes are still evolving. (author)

  7. Transmission Vegetation Management NERC Standard FAC-003-2 Technical...

    Open Energy Info (EERE)

    provide supplemental information and guidance for complying with the requirements of Reliability Standard FAC-003-2. It is a supporting document and provides explanatory background...

  8. Northern California CO<sub>2sub> Reduction Project

    SciTech Connect (OSTI)

    Hymes, Edward

    2010-06-16

    C6 Resources LLC, a wholly owned subsidiary of Shell Oil Company, worked with the US Department of Energy (DOE) under a Cooperative Agreement to develop the Northern California CO<sub>2sub> Reduction Project. The objective of the Project is to demonstrate the viability of using Carbon Capture and Sequestration (CCS) to reduce existing greenhouse gas emissions from industrial sources on a large-scale. The Project will capture more than 700,000 metric tonnes of CO<sub>2sub> per year, which is currently being vented to the atmosphere from the Shell Martinez Refinery in Contra Costa County. The CO<sub>2sub> will be compressed and dehydrated at the refinery and then transported via pipeline to a sequestration site in a rural area in neighboring Solano County. The CO<sub>2sub> will be sequestered into a deep saline formation (more than two miles underground) and will be monitored to assure secure, long-term containment. The pipeline will be designed to carry as much as 1,400,000 metric tonnes of CO<sub>2sub> per year, so additional capacity will be available to accommodate CO<sub>2sub> captured from other industrial sources. The Project is expected to begin operation in 2015. The Project has two distinct phases. The overall objective of Phase 1 was to develop a fully definitive design basis for the Project. The Cooperative Agreement with the DOE provided cost sharing for Phase 1 and the opportunity to apply for additional DOE cost sharing for Phase 2, comprising the design, construction and operation of the Project. Phase 1 has been completed. DOE co-funding is provided by the American Recovery and Reinvestment Act (ARRA) of 2009. As prescribed by ARRA, the Project will stimulate the local economy by creating manufacturing, transportation, construction, operations, and management jobs while addressing the need to reduce greenhouse gas emissions at an accelerated pace. The Project, which will also assist in meeting the CO<sub>2sub> reduction requirements set forth in California's Climate Change law, presents a major opportunity for both the environment as well as the region. C6 Resources is conducting the Project in collaboration with federally-funded research centers, such as Lawrence Berkeley National Lab and Lawrence Livermore National Lab. C6 Resources and Shell have identified CCS as one of the critical pathways toward a worldwide goal of providing cleaner energy. C6 Resources, in conjunction with the West Coast Regional Carbon Sequestration Partnership (WESTCARB), has conducted an extensive and ongoing public outreach and CCS education program for local, regional and state-wide stakeholders. As part of a long term relationship, C6 Resources will continue to engage directly with community leaders and residents to ensure public input and transparency. This topical report summarizes the technical work from Phase 1 of the Project in the following areas; Surface Facility Preliminary Engineering: summarizes the preliminary engineering work performed for CO<sub>2sub> capture, CO<sub>2sub> compression and dehydration at the refinery, and surface facilities at the sequestration site; Pipeline Preliminary Engineering: summarizes the pipeline routing study and preliminary engineering design; Geologic Sequestration: summarizes the work to characterize, model and evaluate the sequestration site; and Monitoring, Verification and Accounting (MVA): summarizes the MVA plan to assure long-term containment of the sequestered CO<sub>2sub>.

  9. Phase equilibria and crystal chemistry of the CaO1/2 Nd{sub 2}O{sub 3}CoO{sub z} system at 885 C in air

    SciTech Connect (OSTI)

    Wong-Ng, W.; Laws, W.; Talley, K.R.; Huang, Q.; Yan, Y.; Martin, J.; Kaduk, J.A.

    2014-07-01

    The phase diagram of the CaO1/2 Nd{sub 2}O{sub 3}CoO{sub z} system at 885 C in air has been determined. The system consists of two calcium cobaltate compounds that have promising thermoelectric properties, namely, the 2D thermoelectric oxide solid solution, (Ca{sub 3?x}Nd{sub x})Co{sub 4}O{sub 9?z} (0?x?0.5), which has a misfit layered structure, and Ca{sub 3}Co{sub 2}O{sub 6} which consists of 1D chains of alternating CoO{sub 6} trigonal prisms and CoO{sub 6} octahedra. Ca{sub 3}Co{sub 2}O{sub 6} was found to be a point compound without the substitution of Nd on the Ca site. The reported Nd{sub 2}CoO{sub 4} phase was not observed at 885 C. A ternary (Ca{sub 1?x}Nd{sub 1+x})CoO{sub 4?z} (x=0) phase, or (CaNdCo)O{sub 4?z}, was found to be stable at this temperature. A solid solution region of distorted perovskite (Nd{sub 1?x}Ca{sub x})CoO{sub 3?z} (0?x?0.25, space group Pnma) was established. In the peripheral binary systems, while a solid solution region was identified for (Nd{sub 1?x}Ca{sub x}){sub 2}O{sub 3?z} (0?x?0.2), Nd was not found to substitute in the Ca site of CaO. Six solid solution tie-line regions and six three-phase regions were determined in the CaONd{sub 2}O{sub 3}CoO{sub z} system in air. - Graphical abstract: Phase diagram of the 1/2 Nd{sub 2}O{sub 3}CaOCoO{sub x} system at 885 C, showing the limits of various solid solutions, and the tie-line relationships of various phases. - Highlights: Phase diagram of the CaO1/2 Nd{sub 2}O{sub 3}CoO{sub z} system constructed. System consists of thermoelectric oxide (Ca{sub 3?x}Nd{sub x})Co{sub 4}O{sub 9?z} (0?x?0.5). Structures of (Nd{sub 1?x}Ca{sub x})CoO{sub 3?z} and (CaNdCo)O{sub 4?z} determined.

  10. Synthesis of novel MoS{sub 2}/g-C{sub 3}N{sub 4} heterojunction photocatalysts with enhanced hydrogen evolution activity

    SciTech Connect (OSTI)

    Tian, Yuming; Ge, Lei; Wang, Kaiyue; Chai, Yuesheng

    2014-01-15

    Novel MoS{sub 2}/g-C{sub 3}N{sub 4} heterojunction photocatalysts were synthesized via a simple impregnation and heating methods. The products were characterized by X-ray diffraction, transmission electron microscopy and UVvis diffuse reflectance spectra. The photocatalytic activities of MoS{sub 2}/g-C{sub 3}N{sub 4} samples were evaluated based on the hydrogen evolution experiments under visible light irradiation (? > 400 nm). The UVvis diffuse reflectance spectra revealed that the MoS{sub 2}/g-C{sub 3}N{sub 4} photocatalysts had strong absorption in the visible light region. The photocatalytic results indicated that the highest H{sub 2} evolution rate of 23.10 ?molh{sup ?1} was achieved on the 0.5 wt.% MoS{sub 2}g-C{sub 3}N{sub 4} sample, which was enhanced by 11.3 times compared to pure g-C{sub 3}N{sub 4}. This study may provide an approach to the development of novel heterojunction photocatalysts for hydrogen production under visible light irradiation. - Highlights: MoS{sub 2}/g-C{sub 3}N{sub 4} photocatalyst is obtained by simple impregnation and heating methods. and determined by XRD, TEM, UV-vis diffuse reflectance spectra. the photocatalysts had strong absorption in the visible light region. the highest H2 evolution rate was achieved on the 0.5wt% samples.

  11. Optical response of nongranular high- T sub c Y sub 1 Ba sub 2 Cu sub 3 O sub 7 sub minus x superconducting thin films

    SciTech Connect (OSTI)

    Frenkel, A. ); Saifi, M.A.; Venkatesan, T.; England, P. ); Wu, X.D.; Inam, A. )

    1990-03-15

    We have investigated the optical response of {ital c}-axis oriented crystalline Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7}{sub {minus}{ital x}} thin films (bridge and meander devices) on strontium titanate and MgO substrates. cw optical response to a He-Ne laser radiation (wavelength of 0.63 {mu}m) was primarily bolometric. The pulsed optical response was studied with {ital Q}-switched and mode-locked {ital Q}-switched short pulses from a Nd:YAG laser at the wavelength of 1.06 {mu}m. We identify two distinct components contributing to the pulsed optical response: a nonbolometric (as fast as 1 ns) and a bolometric component (several ns). The bolometric component is strong at temperatures in the vicinity of the transition region to the normal state. The nonbolometric component is dominant at temperatures below the transition region showing weak temperature dependence and a linear dependence on the bias current. These results are discussed using the flux motion model and also electron-phonon scattering relaxation dynamics of nonequilibrium superconductors based on the theory of Bardeen-Cooper-Schrieffer. The results suggest that with proper optimization of device parameters (geometry, critical current density, etc.) sensitive bolometers and high-speed detectors covering a broad electromagnetic spectrum (visible and infrared) may be developed.

  12. Interface-dependent magnetotransport properties for thin Pt films on ferrimagnetic Y{sub 3}Fe{sub 5}O{sub 12}

    SciTech Connect (OSTI)

    Shiomi, Y.; Ohtani, T.; Iguchi, S.; Sasaki, T.; Qiu, Z.; Nakayama, H.; Uchida, K.; Saitoh, E.

    2014-06-16

    We have studied magnetoresistance and Hall effects for 1.8-nm-thick Pt films grown on a ferrimagnetic insulator Y{sub 3}Fe{sub 5}O{sub 12} in a wide temperature (0.46–300 K) and magnetic-field (−15 to 15 T) region. In the low-temperature regime where quantum corrections to conductivity are observed, weak antilocalization behavior observed in Pt films is critically suppressed when the film is attached to Y{sub 3}Fe{sub 5}O{sub 12}. Hall resistance in the Pt film is also affected by Y{sub 3}Fe{sub 5}O{sub 12}, and it exhibits logarithmic temperature dependence in a broad temperature range. The magnetotransport properties in the high-field range are significantly influenced by the interface between Pt and Y{sub 3}Fe{sub 5}O{sub 12}.

  13. Surface phase of TiO{sub 2} modified with La{sub 2}O{sub 3} and its effect on the photocatalytic H{sub 2} evolution

    SciTech Connect (OSTI)

    Zhang, Yangyang [College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Liaoning, 113001 (China); Zhang, Jing, E-mail: jingzhang_dicp@live.cn [College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Liaoning, 113001 (China); Xu, Qian [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning (China); Yan, Song; Zhao, Shanlin; Luo, Genxiang [College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Liaoning, 113001 (China); Li, Can, E-mail: canli@dicp.ac.cn [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning (China)

    2014-05-01

    Graphical abstract: The La{sub 2}O{sub 3}/TiO{sub 2}-900 C (or La{sub 2}O{sub 3}/Ti(OH){sub 4}-900 C), with surface anatase phase, show the similar photocatalytic activity. The presence of the surface anatase phase is important for high photocatalytic activity of TiO{sub 2} modified with La{sub 2}O{sub 3} (La{sub 2}O{sub 3}/Ti(OH){sub 4}-900 C or La{sub 2}O{sub 3}/Ti(OH){sub 4}-900 C){sub .} - Highlights: Loading La{sub 2}O{sub 3} on anatase TiO{sub 2} is an effective method for stabilizing the anatase phases both in the surface and in the bulk region. The high crystallinity of the surface anatase phase is important for high photocatalytic activity of TiO{sub 2} modified with La{sub 2}O{sub 3.} - Abstract: TiO{sub 2} nanoparticles modified with La{sub 2}O{sub 3} were prepared by an impregnation method using anatase TiO{sub 2} support (La{sub 2}O{sub 3}/TiO{sub 2}) or amorphous Ti(OH){sub 4} support (La{sub 2}O{sub 3}/Ti(OH){sub 4}). The bulk and surface crystalline phases of La{sub 2}O{sub 3}/TiO{sub 2} (or La{sub 2}O{sub 3}/Ti(OH){sub 4}) have been characterized by X-ray powder diffraction (XRD) and UV Raman spectroscopy. Besides, morphology and particle size of La{sub 2}O{sub 3}/TiO{sub 2} and La{sub 2}O{sub 3}/Ti(OH){sub 4} samples have been determined by TEM (transmission electron microscope) and BrunauerEmmettTeller (BET), respectively. It is found that the phase transformation and increase of the particle size of TiO{sub 2} can be more effectively inhibited in the La{sub 2}O{sub 3}/TiO{sub 2} than in the La{sub 2}O{sub 3}/Ti(OH){sub 4}. Photocatalytic experiments indicated that the La{sub 2}O{sub 3}/TiO{sub 2} (or La{sub 2}O{sub 3}/Ti(OH){sub 4}) samples with surface anatase phase have the similar overall photocatalytic activities. Moreover, it is found that the high crystallinity of surface anatase phase is benefit for the high photocatalytic activity of TiO{sub 2} modified with La{sub 2}O{sub 3}.

  14. Microdomain Formation, Oxidation, and Cation Ordering in LaCa<sub>2sub>Fe>3sub>O>8+ysub>

    SciTech Connect (OSTI)

    Price, Patrick M.; Browning, Nigel D.; Butt, Darryl P.

    2015-03-23

    The compound LaCa<sub>2sub>Fe>3sub>O>8+ysub>, also known as the Grenier phase, is known to undergo an order-disorder transformation (ODT) at high temperatures. Oxidation has been observed when the compound is cooled in air after the ODT. In this study, we have synthesized the Grenier compound in air using traditional solid state reactions and investigated the structure and composition before and after the ODT. Thermal analysis showed that the material undergoes an order-disorder transformation in both oxygen and argon atmospheres with dynamic, temperature dependent, oxidation upon cooling. Results from scanning transmission electron microscopy (STEM) suggest that the Grenier phase has preferential segregation of Ca and La on the two crystallographic A-sites before the ODT, but a random distribution above the ODT temperature. Furthermore, STEM images suggest the possibility that oxygen excess may exist in La-rich regions within microdomains rather than at microdomain boundaries.

  15. Fragile structural transition in Mo<sub>3sub>Sb>7sub>

    SciTech Connect (OSTI)

    Yan, Jiaqiang -Q.; McGuire, Michael A; May, Andrew F; Parker, David S.; Mandrus, D. G.; Sales, Brian C.

    2015-08-10

    Mo<sub>3sub>Sb>7sub> single crystals lightly doped with Cr, Ru, or Te are studied in order to explore the interplay between superconductivity, magnetism, and the cubic-tetragonal structural transition. The structural transition at 53 K is extremely sensitive to Ru or Te substitution which introduces additional electrons, but robust against Cr substitution. We observed no sign of a structural transition in superconducting Mo<sub>2.91sub>Ru>0.09sub>Sb>7sub> and Mo<sub>3sub>Sb>6.975sub>Te>0.025sub>. In contrast, 3 at.% Cr doping only slightly suppresses the structural transition to 48 K while leaving no trace of superconductivity above 1.8 K. Analysis of magnetic properties suggests that the interdimer interaction in Mo<sub>3sub>Sb>7sub> is near a critical value and essential for the structural transition. Futhermore, all dopants suppress the superconductivity of Mo<sub>3sub>Sb>7sub>. The tetragonal structure is not necessary for superconductivity.

  16. Piezo-/dielectric properties of perovskite-structure high-temperature relaxor ferroelectrics: The Pb(Lu{sub 1/2}Nb{sub 1/2})O{sub 3}–Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}–PbTiO{sub 3} ternary ceramics

    SciTech Connect (OSTI)

    Li, Tao; Long, Xifa

    2014-03-01

    Graphical abstract: - Highlights: • Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}-based ternary ferroelectric ceramics were prepared by solid-state synthesis method. • Morphotropic phase boundary region has been determined by XRD, di-/piezoelectric properties. • The compositions near MPB region exhibit excellent piezoelectric properties. - Abstract: A new compositional system of relaxor ferroelectrics was investigated based on the high piezoelectricity Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}–PbTiO{sub 3} ferroelectric perovskite family. Compositions were fabricated near an estimated morphotropic phase boundary (MPB) of the Pb(Lu{sub 1/2}Nb{sub 1/2})O{sub 3}–Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}–PbTiO{sub 3} (PLZNT) ternary system by a two-step synthetic process. Their structures have been analyzed by means of X-ray diffraction technique. On the basis of X-ray powder diffraction, the morphotropic phase boundary (MPB) region for the ternary system was obtained. The Curie temperature T{sub C} of ternary system varied from 240 °C to 330 °C and the coercive fields E{sub c}s > 10 kV/cm. The values of piezoelectric coefficients d{sub 33} vary in the range of 260–450 pC/N with different PZN contents. It is worth noting that the optimum compositions were located at MPB region but near the tetragonal phase. The new PLZNT ceramics exhibit wider range of T{sub C}s and E{sub c}s, making it a promising material for high-powder ultrasound transducers using in a large temperature range.

  17. Synthesis and photoluminescence properties of Ca{sub 19}Mg{sub 2}(PO{sub 4}){sub 14}:Sm{sup 3+} red phosphor for white light emitting diodes

    SciTech Connect (OSTI)

    Zhu, Ge; Ci, Zhipeng; Shi, Yurong; Wang, Yuhua

    2014-07-01

    Highlights: A novel red phosphor Ca{sub 19}Mg{sub 2}(PO{sub 4}){sub 14}:Sm{sup 3+} was synthesized and investigated firstly. The structure and characteristic luminescence properties are discussed. The excellent thermal stability was found and investigated. It has good color saturation, the CIE is close to that of commercial Y{sub 2}O{sub 3}:Eu{sup 3+}. - Abstract: A series of Sm{sup 3+} doped Ca{sub 19}Mg{sub 2}(PO{sub 4}){sub 14} red phosphors were successfully synthesized. X-ray diffraction analysis indicates that all the samples are single phased. The luminescence property is investigated in detail by measuring their photoluminescence excitation and emission spectra. Ca{sub 19}Mg{sub 2}(PO{sub 4}){sub 14}:Sm{sup 3+} phosphors show strong absorption in 400410 nm region, which is suitable for application in LEDs. When excited at 403 nm, Ca{sub 19}Mg{sub 2}(PO{sub 4}){sub 14}:Sm{sup 3+} phosphor can emit red emission with CIE chromaticity coordinates (0.615, 0.384). The optimal doping concentration of Sm{sup 3+} doped Ca{sub 19}Mg{sub 2}(PO{sub 4}){sub 14} is measured to be 0.02. The thermal quenching property is also measured and compared with the commercial red phosphor Y{sub 2}O{sub 3}:Eu{sup 3+} (Topstar, TXC-RIA). The results indicate Ca{sub 19}Mg{sub 2}(PO{sub 4}){sub 14}:Sm{sup 3+} phosphors have potential to serve as a red phosphor for white LEDs.

  18. Influence of composition modification on Ca{sub 0.5?x}Mg{sub x}Ti{sub 2}(PO{sub 4}){sub 3} (0.0 ? x ? 0.5) nanoparticles as electrodes for lithium batteries

    SciTech Connect (OSTI)

    Vidal-Abarca, C. Aragn, M.J.; Lavela, P.; Tirado, J.L.

    2014-01-01

    Graphical abstract: - Highlights: Cation mixing was determined in the Ca{sub 0.5?x}Mg{sub x}Ti{sub 2}(PO{sub 4}){sub 3} biphasic series. Nanometric Ca{sub 0.15}Mg{sub 0.35}Ti{sub 2}(PO{sub 4}){sub 3} delivered 138 mAh/g at C/20 in lithium cells. Low content of Ca{sup 2+} increases cell volume favoring Li{sup +} insertion in R-3c framework. Diminution of R{sub SEI} and R{sub CT} for Ca{sub 0.15}Mg{sub 0.35}Ti{sub 2}(PO{sub 4}){sub 3} discharged electrodes. Fast electrode response for x = 0.35. - Abstract: The Ca{sub 0.5?x}Mg{sub x}Ti{sub 2}(PO{sub 4}){sub 3} series (0.0 ? x ? 0.5) was prepared by a solgel method. X-ray diffraction patterns showed two rhombohedral phases which coexist for intermediate compositions. Despite of the absence of a solid solution mechanism for the whole stoichiometry range, an appreciable cation mixing was observed in both phases. {sup 31}P MAS NMR spectroscopy revealed that low magnesium contents are incorporated to the calcium compound inducing changes in the ordering of the alkaline earth cations in M{sub 1} sites. Derivative plots of the voltagecapacity curves revealed two reversible regions ascribed to the reduction of Ti{sup 4+} to Ti{sup 3+}, ascribable to the subsequent insertion of lithium ions into M{sub 1} and M{sub 2} vacant sites. Capacity values as high as 138 mAh/g after the first discharge were monitored for nanometric Ca{sub 0.15}Mg{sub 0.35}Ti{sub 2}(PO{sub 4}){sub 3} at C/20. Cell cycling under successive kinetic rates revealed a good capacity retention for samples with x = 0.15 and 0.25. Impedance spectra were recorded in lithium cells discharged after different number of cycles at different C rates. The increase in charge transfer resistance was shown to be an important factor determining the electrode behavior on extended cycling.

  19. Phase transition sequence in Pb-free 0.96(K{sub 0.5}Na{sub 0.5}){sub 0.95}Li{sub 0.05}Nb{sub 0.93} Sb{sub 0.07}O{sub 3}−0.04BaZrO{sub 3} ceramic with large piezoelectric response

    SciTech Connect (OSTI)

    Gao, Jinghui Zhang, Le; Zhang, Ming; Dai, Ye; Hu, Xinghao; Wang, Dong; Zhong, Lisheng; Li, Shengtao; Ren, Shuai; Hao, Yanshuang Fang, Minxia; Ren, Xiaobing

    2015-07-20

    The piezoceramic 0.96(K{sub 0.5}Na{sub 0.5}){sub 0.95}Li{sub 0.05}Nb{sub 0.93}Sb{sub 0.07}O{sub 3}−0.04BaZrO{sub 3} (KNLNS{sub 0.07}-BZ), which shows large piezoelectric response (d{sub 33} ≈ 425 pC/N), has been considered as one of the promising Pb-free substitutions for Pb(Zr,Ti)O{sub 3}. In this paper, we investigate the phase transition sequence for KNLNS{sub 0.07}-BZ by employing the dielectric measurement, mechanical spectroscopy, as well as Raman spectroscopy. Two ferroelectric-ferroelectric transitions have been detected by inspecting anomalies in the spectra, indicating the existence of three ferroelectric phases. Moreover, in-situ X-ray diffraction study has been further performed on KNLNS{sub 0.07}-BZ to identify the crystal structure for each phase. The result reveals that the phase sequence for KNLNS{sub 0.07}-BZ evolves from tetragonal (T) to rhombohedral (R) via an intermediate orthorhombic (O) phase. And the piezoelectric-optimal region for KNLNS{sub 0.07}-BZ locates on a T-O boundary rather than the previously reported T-R boundary. Strong piezoelectricity may stem from the easier polarization rotation on the T-O boundary with reduced polarization anisotropy.

  20. Structural and chemical ordering of Heusler Co<sub>xsub>MnyGez> epitaxial films on Ge (111). Quantitative study using traditional and anomalous x-ray diffraction techniques

    SciTech Connect (OSTI)

    Collins, B. A.; Chu, Y.; He, L.; Haskel, D.; Tsui, F.

    2015-12-14

    We found that epitaxial films of Co<sub>xsub>MnyGez> grown on Ge (111) substrates by molecular-beam-epitaxy techniques have been investigated as a continuous function of composition using combinatorial synchrotron x-ray diffraction (XRD) and x-ray fluorescence (XRF) spectroscopy techniques. A high-resolution ternary epitaxial phase diagram is obtained, revealing a small number of structural phases stabilized over large compositional regions. Ordering of the constituent elements in the compositional region near the full Heusler alloy Co<sub>2sub>MnGe has been examined in detail using both traditional XRD and a new multiple-edge anomalous diffraction (MEAD) technique. Multiple-edge anomalous diffraction involves analyzing the energy dependence of multiple reflections across each constituent absorption edge in order to detect and quantify the elemental distribution of occupation in specific lattice sites. Results of this paper show that structural and chemical ordering are very sensitive to the Co : Mn atomic ratio, such that the ordering is the highest at an atomic ratio of 2 but significantly reduced even a few percent off this ratio. The in-plane lattice is nearly coherent with that of the Ge substrate, while the approximately 2% lattice mismatch is accommodated by the out-of-plane tetragonal strain. Furthermore, the quantitative MEAD analysis reveals no detectable amount (<0.5%) of Co-Mn site swapping, but instead high levels (26%) of Mn-Ge site swapping. Increasing Ge concentration above the Heusler stoichiometry (Co <sub>0.5sub> Mn <sub>0.25 sub>Ge <sub>0.25 sub>) is shown to correlate with increased lattice vacancies, antisites, and stacking faults, but reduced lattice relaxation. The highest degree of chemical ordering is observed off the Heusler stoichiometry with a Ge enrichment of 5 at.%.

  1. Fe<sub>2sub>O>3sub>–TiO>2sub> core–shell nanorod arrays for visible light photocatalytic applications

    SciTech Connect (OSTI)

    Yao, Kun; Basnet, Pradip; Sessions, Henry; Larsen, George K.; Murph, Simona E. Hunyadi; Zhao, Yiping

    2015-11-11

    By using the glancing angle deposition technique and post-deposition annealing, Fe<sub>2sub>O>3sub>–TiO>2sub> core-shell nanorod arrays with specific crystalline states can be designed and fabricated. The Fe<sub>2sub>O>3sub>–TiO>2sub> core-shell samples annealed at temperatures greater than 450°C formed α-Fe<sub>2sub>O>3sub> and anatase TiO<sub>2sub>, and showed higher catalytic efficiency for the degradation of methylene blue (MB) under visible light illumination when compared with pure anatase TiO<sub>2sub> or α-Fe<sub>2sub>O>3sub> nanorod arrays. Solar conversion of carbon dioxide and water vapor in the presence of Fe<sub>2sub>O>3sub>–TiO>2sub> core-shell nanorod arrays was also investigated. Carbon monoxide, hydrogen, methane, and methanol along with other hydrocarbons were produced after only several hours’ exposure under ambient sunlight. It was determined that the core-shell structure showed greater efficiency for solar CO<sub>2sub> conversion than the pure TiO<sub>2sub> nanorod arrays.

  2. A novel broadband emission phosphor Ca{sub 2}KMg{sub 2}V{sub 3}O{sub 12} for white light emitting diodes

    SciTech Connect (OSTI)

    Li, Junfu; Qiu, Kehui; Li, Junfeng; Li, Wei; Yang, Qian; Li, Junhan

    2010-05-15

    A novel broadband emission phosphor Ca{sub 2}KMg{sub 2}V{sub 3}O{sub 12} was first synthesized by solution combustion method. The X-ray diffraction showed that Ca{sub 2}KMg{sub 2}V{sub 3}O{sub 12} phase can be obtained at 600-900 {sup o}C through combustion route. The crystal structure of this material was refined by Rietveld method using powder X-ray diffraction. It crystallizes in cubic system and belongs to space group Ia3d with z = 8, a = 0.12500 nm. The excitation band of Ca{sub 2}KMg{sub 2}V{sub 3}O{sub 12} peaks at 320 nm in a region between 260 nm and 425 nm, and the emission spectrum exhibits an intense band centered at about 528 nm covering from 400 nm to 800 nm. The colour coordinates of samples prepared at different ignition temperatures are in a range of x = 0.323-0.339, y = 0.430-0.447.

  3. Phase evolution studies in CaZrTi{sub 2}O{sub 7}−RE{sub 2}Ti{sub 2}O{sub 7} (RE = Nd{sup 3+}, Sm{sup 3+}) system: Futuristic ceramic host matrices for nuclear waste immobilization

    SciTech Connect (OSTI)

    Jafar, M. Achary, S. N. Tyagi, A. K.

    2014-04-24

    Series of compositions with general stoichiometry as Ca{sub 1−x}Zr{sub 1−x}RE{sub 2x}Ti{sub 2}O{sub 7} (RE = Nd{sup 3+}, Sm{sup 3+}) were prepared by solid state reaction and characterized by powder x-ray diffraction technique to unravel the phase fields in the title systems. The phase fields in CaZrTi{sub 2}O{sub 7−}Nd{sub 2}Ti{sub 2}O{sub 7} and CaZrTi{sub 2}O{sub 7−}Sm{sub 2}Ti{sub 2}O{sub 7} systems differed significantly at the rareearth rich regions. The common phase fields like zirconolite-2M, zirconolite-4M, cubic perovskite are observed at the zirconolite rich regions of both systems. Depending on the structure of RE{sub 2}Ti{sub 2}O{sub 7} phase, the cubic pyrochlore or monoclinic RE{sub 2}Ti{sub 2}O{sub 7} phases are observed in the studied system. The observed phase fields in these two systems indicate ionic radius of the rare-earth ion has a dominating role in the phase relations. Further details of the phases and their homogeneity are explained in the text of the manuscript.

  4. The effect of strain induced by Ag underlayer on saturation magnetization of partially ordered Fe<sub>16sub>N>2sub> thin films

    SciTech Connect (OSTI)

    Yang, Meiyin; Allard, Lawrence F.; Ji, Nian; Zhang, Xiaowei; Yu, Guang-Hua; Wang, Jian -Ping

    2013-12-12

    Small angle neutron scattering (SANS) and scanning transmission electron microscopy (STEM) were used to study film formation by magnesium alloys AZ31B (Mg-3Al-1Zn base) and ZE10A (Elektron®717, E717: Mg-1Zn + Nd, Zr) in H<sub>2sub>O and D<sub>2sub>O with and without 1 or 5 wt.% NaCl. No SANS scattering changes were observed after 24 h D<sub>2sub>O or H<sub>2sub>O exposures compared with as received (unreacted) alloy, consistent with relatively dense MgO-base film formation. However, exposure to 5 wt.% NaCl resulted in accelerated corrosion, with resultant SANS scattering changes detected. The SANS data indicated both particle and rough surface (internal and external) scattering, but with no preferential size features. The films formed in 5 wt.% NaCl consisted of a thin, inner MgO-base layer, and a nano-porous and filamentous Mg(OH)<sub>2sub> outer region tens of microns thick. Chlorine was detected extending to the inner MgO-base film region, with segregation of select alloying elements also observed in the inner MgO, but not the outer Mg(OH)<sub>2sub>. Modeling of the SANS data suggested that the outer Mg(OH)<sub>2sub> films had very high surface areas, consistent with loss of film protectiveness. Here, implications for the NaCl corrosion mechanism, and the potential utility of SANS for Mg corrosion, are discussed.

  5. Exploring the electronic structure and optical properties of the quaternary selenide compound, Ba{sub 4}Ga{sub 4}SnSe{sub 12}: For photovoltaic applications

    SciTech Connect (OSTI)

    Azam, Sikander; Khan, Saleem Ayaz; Goumri-Said, Souraya

    2015-09-15

    Due to huge demand on discovering new materials for energy, we used first-principle calculations to explore the electronic structure and optical properties of a recent quaternary selenide, namely Ba{sub 4}Ga{sub 4}SnSe{sub 12}. The electronic structure and the optical properties of Ba{sub 4}Ga{sub 4}SnSe{sub 12} were calculated through a reliable approach of Engle Vosko-GGA (EV-GGA). We found that Ba{sub 4}Ga{sub 4}SnSe{sub 12} has a direct band gap of 2.14 eV positioned at Γ. Acquiring the fundamental characteristics of Ba{sub 4}Ga{sub 4}SnSe{sub 12,} we studied the linear optical properties like dielectric function in the energy range of 0–14 eV. From the dielectric function we noticed a weak directional anisotropy for the two components. The absorption spectrum indicates the possibility of greater multiple direct and indirect inter-band transitions in the visible regions and shows similar behavior with experimental spectrum. Ba{sub 4}Ga{sub 4}SnSe{sub 12} can be used as shielding material from UV radiations. Present study predicts that the Ba{sub 4}Ga{sub 4}SnSe{sub 12} is promising for photovoltaic applications due to their high absorption of solar radiations and photoconductivity in the visible range. - Graphical abstract: Interesting quaternary selenide compound, Ba{sub 4}Ga{sub 4}SnSe{sub 12}, for photovoltaic applications. - Highlights: • Ba{sub 4}Ga{sub 4}SnSe{sub 12} is a quaternary selenide designed for PV and thermoelectric. • Ba{sub 4}Ga{sub 4}SnSe{sub 12} has a direct band gap of 2.14 eV. • Ba{sub 4}Ga{sub 4}SnSe{sub 12,} has a maximum reflectivity in the visible and UV regions.

  6. Electronic and magnetic properties of Si substituted Fe<sub>3sub>Ge

    SciTech Connect (OSTI)

    Shanavas, Kavungal Veedu; McGuire, Michael A.; Parker, David S.

    2015-09-23

    Using first principles calculations we studied the effect of Si substitution in the hexagonal Fe<sub>3sub>Ge. We find the low temperature magnetic anisotropy in this system to be planar and originating mostly from the spin-orbit coupling in Fe-d states. Reduction of the unitcell volume reduces the in-plane magnetic anisotropy, eventually turning it positive which reorients the magnetic moments to the axial direction. We find that substituting Ge with the smaller Si ions also reduces the anisotropy, potentially enhancing the region of stability of the axial magnetization, which is beneficial for magnetic applications. Thus our experimental measurements on samples of Fe<sub>3sub>Ge>1–xsub>Six> confirm these predictions and show that substitution of about 6% of the Ge with Si increases by approximately 35 K the temperature range over which anisotropy is uniaxial.

  7. Investigation of La<sub>xSr>1-xsub>CoyM>1-ysub>O>3-dsub> (M = Mn Fe) perovskite materials as thermochemical energy storage media.

    SciTech Connect (OSTI)

    Babiniec, Sean Michael; Ambrosini, Andrea; Coker, Eric Nicholas; Miller, James E.

    2015-06-23

    Materials in the La<sub>xSr>1–xsub>CoyMn>1–ysub>O>3–δsub> (LSCM) and La<sub>xSr>1–xsub>CoyFe>1–ysub>O>3–δsub> (LSCF) families are candidates for high-temperature thermochemical energy storage due to their facility for cyclic endothermic reduction and exothermic oxidation. A set of 16 LSCM and 21 LSCF compositions were synthesized by a modified Pechini method and characterized by powder X-ray diffraction and thermogravimetric analysis. All materials were found to be various symmetries of the perovskite phase. LSCM was indexed as tetragonal, cubic, rhombohedral, or orthorhombic as a function of increased lanthanum content. For LSCF, compositions containing low lanthanum content were indexed as cubic while materials with high lanthanum content were indexed as rhombohedral. An initial screening of redox activity was completed by thermogravimetric analysis for each composition. The top three compositions with the greatest recoverable redox capacity for each family were further characterized in equilibrium thermogravimetric experiments over a range of temperatures and oxygen partial pressures. As a result, these equilibrium experiments allowed the extraction of thermodynamic parameters for LSCM and LSCF compositions operated in thermochemical energy storage conditions.

  8. Behavior of the magnetocaloric effect and critical exponents in La{sub 0.67}Sr{sub 0.33}Mn{sub 1−x}V{sub x}O{sub 3} manganite oxide

    SciTech Connect (OSTI)

    Mnefgui, S.; Zaidi, N.; Dhahri, A.; Hlil, E.K.; Dhahri, J.

    2014-07-01

    We have investigated the magnetocaloric effect along with magnetic phase transition and critical exponent analysis in mixed manganite La{sub 0.67}Sr{sub 0.33}Mn{sub 1−x}V{sub x}O{sub 3} (0≤x≤0.15). To determine the nature of the paramagnetic to ferromagnetic phase transition, found to be of second-order, we performed a critical exponents study by dc-magnetization M(H,T) measurements around the Curie temperature T{sub C}. Modified Arrott plot method has been adopted to study the critical behavior of the compounds at their transition region, the values of critical exponents β, γ and δ are close to those expected for three-dimensional Heisenberg class with short-range interaction. A large magnetic entropy change |ΔS{sub M}| deduced from isothermal magnetization curves, has been observed in our samples with a peak centered on their respective T{sub C}. With increase in vanadium content, the temperature corresponding to the maximum entropy change as well as the magnetic transition temperature gradually shifts to low temperatures. The field dependence of the magnetic entropy change is also analyzed, which shows the power law dependence namely, ΔS{sub M}∝H{sup n}. Relative cooling power increases from 205 J/kg for x=0.00 to 258 J/Kg for x=0.15 making these materials a promising candidates for magnetic refrigeration near room temperature. - Graphical abstract: Scaling plot below and above T{sub C} using the β and γ exponents determined from the Arrot plot method of La{sub 0.67}Sr{sub 0.33}Mn{sub 1−x}V{sub x}O{sub 3} for x=0.15. - Highlights: • The paramagnetic to ferromagnetic phase transition of La{sub 0.67}Sr{sub 0.33}Mn{sub 1−x}V{sub x}O{sub 3} (0≤x≤0.15) is found to be of second-order. • The field dependence of the magnetic entropy shows the power law dependence namely, ΔS{sub M}∝H{sup n}. • Moderate values of −ΔS{sub M}{sup max} and RCP make the La{sub 0.67}Sr{sub 0.33}Mn{sub 1−x}V{sub x}O{sub 3} compounds potential candidates for magnetic refrigeration applications.

  9. Electronic structure, irreversibility line and magnetoresistance of Cu<sub>0.3sub>Bi>2sub>Se>3sub> superconductor

    SciTech Connect (OSTI)

    Hemian, Yi; Gu, Genda; Chen, Chao -Yu; Sun, Xuan; Xie, Zhuo -Jin; Feng, Ya; Liang, Ai -Ji; Peng, Ying -Ying; He, Shao -Long; Zhao, Lin; Liu, Guo -Dong; Dong, Xiao -Li; Zhang, Jun; Chen, Chuang -Tian; Xu, Zu -Yan; Zhou, X. -J.

    2015-06-01

    Cu<sub>xBi>2sub>Se>3sub> is a superconductor that is a potential candidate for topological superconductors. We report our laser-based angle-resolved photoemission measurement on the electronic structure of the Cu<sub>xBi>2sub>Se>3sub> superconductor, and a detailed magneto-resistance measurement in both normal and superconducting states. We find that the topological surface state of the pristine Bi<sub>2sub>Se>3sub> topological insulator remains robust after the Cu-intercalation, while the Dirac cone location moves downward due to electron doping. Detailed measurements on the magnetic field-dependence of the resistance in the superconducting state establishes an irreversibility line and gives a value of the upper critical field at zero temperature of ~4000 Oe for the Cu<sub>0.3sub>Bi>2sub>Se>3sub> superconductor with a middle point T<sub>c> of 1.9K. The relation between the upper critical field Hc2 and temperature T is different from the usual scaling relation found in cuprates and in other kinds of superconductors. Small positive magneto-resistance is observed in Cu<sub>0.3sub>Bi>2sub>Se>3sub> superconductors up to room temperature. As a result, these observations provide useful information for further study of this possible candidate for topological superconductors.

  10. A novel red phosphor Ca{sub 12}Al{sub 14}O{sub 32}Cl{sub 2}:Eu{sup 3+} for near UV white light-emitting diodes

    SciTech Connect (OSTI)

    Yang, Zhigang; Zhao, Zhengyan; Shi, Yurong; Wang, Yuhua

    2013-10-15

    Graphical abstract: - Highlights: Novel red phosphor Ca{sub 12}Al{sub 14}O{sub 32}Cl{sub 2}:Eu{sup 3+} was prepared by solid-state reaction. Excitation spectra suggested an obvious absorption in near-ultraviolet region. Under 392 nm excitation, the phosphors exhibited a red emission at 614 nm. Ca{sub 12}Al{sub 14}O{sub 32}Cl{sub 2}:Eu{sup 3+} could be potentially applied in near UV white LEDs. - Abstract: A novel red phosphor Ca{sub 12}Al{sub 14}O{sub 32}Cl{sub 2}:Eu{sup 3+} was synthesized using a solid-state reaction method, and its luminescence characteristics and charge compensators effect (Li{sup +}, Na{sup +}, K{sup +}) were investigated. The excitation spectra showed a obvious absorption in near-ultraviolet region. Under 392 nm excitation, the phosphors exhibited an intense red emission at 614 nm. The Commission Internationale de lEclairage (CIE) chromaticity coordinates and quantum efficiency (QE) were (0.65, 0.35) and 62.3%, respectively. The good color saturation, high quantum efficiency and small thermal-quenching properties indicate that Ca{sub 12}Al{sub 14}O{sub 32}Cl{sub 2}:Eu{sup 3+} could be potentially applied in near UV white light-emitting diodes.

  11. Discovery of a metastable Al<sub>20sub>Sm>4sub> phase

    SciTech Connect (OSTI)

    Ye, Z.; Zhang, F.; Sun, Y.; Mendelev, M. I.; Ott, R. T.; Park, E.; Besser, M. F.; Kramer, M. J.; Ding, Z.; Wang, C. -Z.; Ho, K. -M.

    2015-03-09

    In this study, we present an efficient genetic algorithm, integrated with experimental diffraction data, to solve a nanoscale metastable Al<sub>20sub>Sm>4sub> phase that evolves during crystallization of an amorphous magnetron sputtered Al<sub>90sub>Sm>10sub> alloy. The excellent match between calculated and experimental X-ray diffraction patterns confirms an accurate description of this metastable phase. Molecular dynamic simulations of crystal growth from the liquid phase predict the formation of disordered defects in the devitrified crystal.

  12. K{sub 2}Fe{sub 2}B{sub 2}O{sub 7}: A transparent nonlinear optical crystal with frustrated magnetism

    SciTech Connect (OSTI)

    Wang Yonggang [Beijing Center for Crystal Research and Development, Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Li, R.K., E-mail: rkli@mail.ipc.ac.c [Beijing Center for Crystal Research and Development, Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2010-06-15

    A new noncentrosymmetric ferroborate crystal, K{sub 2}Fe{sub 2}B{sub 2}O{sub 7}, has been grown from high temperature melt. Structure solution from single crystal X-ray diffraction shows that the title compound crystallizes in a trigonal space group P321 with cell dimensions of a=8.7475(12) A and c=8.5124(17) A. In the structure, FeO{sub 4} tetrahedron shares its three basal oxygen atoms with BO{sub 3} triangles forming a two-dimensional layer in the ab plane and the layers are connected by the apical Fe-O bonds along the c direction. The crystal is transparent in the visible and near infrared region from 500 to 2000 nm with three pronounced absorption bands ascribed to d-d transitions of tetrahedrally coordinated Fe{sup 3+} ions. Though, structurally analog to K{sub 2}Al{sub 2}B{sub 2}O{sub 7}, the further twisting of the BO{sub 3} groups between adjacent layers reduces its optical nonlinearity to a second-harmonic generation intensity of about 0.4 times that of KDP. Spin-glass behavior is observed at 20 K which is probably due to geometrically magnetic frustration of the triangular Fe net in the ab plane. - Graphical abstract: Single crystal of a new ferroborate K{sub 2}Fe{sub 2}B{sub 2}O{sub 7}, space group P321, a=8.7475(3) A, c=8.5124(3) A, was obtained and characterized. It exhibits considerable SHG efficiency and frustrated magnetism originated from the triangular Fe net in the ab plane.

  13. Measurement of the correlation between flow harmonics of different order in lead-lead collisions at √s<sub>NN> = 2.76 TeV with the ATLAS detector

    SciTech Connect (OSTI)

    Aad, G.

    2015-09-14

    Correlations between the elliptic or triangular flow coefficients v<sub>m> (m=2 or 3) and other flow harmonics v<sub>n> (n=2 to 5) are measured using √s<sub>NN>=2.76 TeV Pb+Pb collision data collected in 2010 by the ATLAS experiment at the LHC, corresponding to an integrated luminosity of 7 μb-1. The v<sub>m-vn> correlations are measured in midrapidity as a function of centrality, and, for events within the same centrality interval, as a function of event ellipticity or triangularity defined in a forward rapidity region. For events within the same centrality interval, v<sub>3sub> is found to be anticorrelated with v<sub>2sub> and this anticorrelation is consistent with similar anticorrelations between the corresponding eccentricities, ε<sub>2sub> and ε<sub>3sub>. However, it is observed that v<sub>4sub> increases strongly with v<sub>2sub>, and v<sub>5sub> increases strongly with both v<sub>2sub> and v<sub>3sub>. The trend and strength of the vm-vn correlations for n=4 and 5 are found to disagree with ε<sub>m-εn> correlations predicted by initial-geometry models. Instead, these correlations are found to be consistent with the combined effects of a linear contribution to vn and a nonlinear term that is a function of v2<sub>2sub> or of v<sub>2sub>v>3sub>, as predicted by hydrodynamic models. A simple two-component fit is used to separate these two contributions. The extracted linear and nonlinear contributions to v<sub>4sub> and v<sub>5sub> are found to be consistent with previously measured event-plane correlations.

  14. Thermochemistry of La{sub 0.7}Sr{sub 0.3}Mn{sub 1-x}Fe{sub x}O{sub 3} solid solutions (0

    SciTech Connect (OSTI)

    Kemik, Nihan; Takamura, Yayoi; Navrotsky, Alexandra

    2011-08-15

    The structure, the energetics and the internal redox reactions of La{sub 0.7}Sr{sub 0.3}Fe{sub x}Mn{sub 1-x}O{sub 3} have been studied in the complete solid solution range 0.0sub 0.70}Sr{sub 0.30}Fe{sub x}Mn{sub 1-x}O{sub 3} solid solution. - Graphical abstract: Enthalpy of mixing ({Delta}H{sub mix}) of La{sub 0.7}Sr{sub 0.3}Mn{sub 1-x}Fe{sub x}O{sub 3-{gamma}} solid solution at room temperature as a function of Fe/(Fe+Mn) ratio, x. Linear fits for the two regions at low and high x are shown as solid lines. The inset shows the content of Mn{sup 3+}, Mn{sup 4+}, Fe{sup 3+} and Fe{sup 4+} as a function of x based on the work by Jonker. The redox reactions between different valence states of Fe and Mn dominate the energetic behavior of the solid solution. Highlights: > Investigated the structure, the energetics and the internal redox reactions of La{sub 0.7}Sr{sub 0.3}Mn{sub 1-x}Fe{sub x}O{sub 3}. > Determined the formation and mixing enthalpy by high temperature oxide melt solution calorimetry. > Symmetry of the perovskite, transition metal valence and energetics are interdependent. > Thermochemical data shows convincing evidence of the interplay between the Mn{sup 4+} and the Fe{sup 4+} ions. > Balance between different valences of Mn and Fe dominates the energetics of La{sub 0.7}Sr{sub 0.3}Fe{sub x}Mn{sub 1-x}O{sub 3}.

  15. Superconductivity in strong spin orbital coupling compound Sb<sub>2sub>Se>3sub>

    SciTech Connect (OSTI)

    Kong, P. P.; Sun, F.; Xing, L. Y.; Zhu, J.; Zhang, S. J.; Li, W. M.; Liu, Q. Q.; Wang, X. C.; Feng, S. M.; Yu, X. H.; Zhu, J. L.; Yu, R. C.; Yang, W. G.; Shen, G. Y.; Zhao, Y. S.; Ahuja, R.; Mao, H. K.; Jin, C. Q.

    2014-10-20

    Recently, A<sub>2sub>B>3sub> type strong spin orbital coupling compounds such as Bi<sub>2sub>Te>3sub>, Bi<sub>2sub>Se>3sub> and Sb<sub>2sub>Te>3sub> were theoretically predicated to be topological insulators and demonstrated through experimental efforts. The counterpart compound Sb<sub>2sub>Se>3sub> on the other hand was found to be topological trivial, but theoretical studies indicated that the pressure might induce Sb<sub>2sub>Se>3sub> into a topological nontrivial state. We report on the discovery of superconductivity in Sb<sub>2sub>Se>3sub> single crystal induced via pressure. Our experiments indicated that Sb<sub>2sub>Se>3sub> became superconductive at high pressures above 10 GPa proceeded by a pressure induced insulator to metal like transition at ~3 GPa which should be related to the topological quantum transition. The superconducting transition temperature (T<sub>C>) increased to around 8.0 K with pressure up to 40 GPa while it keeps ambient structure. As a result, high pressure Raman revealed that new modes appeared around 10 GPa and 20 GPa, respectively, which correspond to occurrence of superconductivity and to the change of T<sub>C> slop as the function of high pressure in conjunction with the evolutions of structural parameters at high pressures.

  16. 57Fe Mössbauer study of Lu<sub>2sub>Fe>3sub>Si>5 sub>iron silicide superconductor

    SciTech Connect (OSTI)

    Ma, Xiaoming; Ran, Sheng; Pang, Hua; Li, Fashen; Canfield, Paul C.; Bud'ko, Sergey L.

    2015-03-28

    With the advent of Fe–As based superconductivity it has become important to study how superconductivity manifests itself in details of 57Fe Mössbauer spectroscopy of conventional, Fe-bearing superconductors. The iron-based superconductor Lu<sub>2sub>Fe>3sub>Si>5sub> has been studied by 57Fe Mössbauer spectroscopy over the temperature range from 4.4 K to room temperature with particular attention to the region close to the superconducting transition temperature (T<sub>c>=6.1 K). Furthermore, consistent with the two crystallographic sites for Fe in this structure, the observed spectra appear to have a pattern consisting of two doublets over the whole temperature range. The value of Debye temperature was estimated from temperature dependence of the isomer shift and the total spectral area and compared with the specific heat capacity data. As a result, neither abnormal behavior of the hyperfine parameters at or near T<sub>c>, nor phonon softening were observed.

  17. Magnetic structures of R<sub>5sub>Ni>2sub>In>4sub> and R<sub>11sub>Ni>4sub>In>9sub> ( R = Tb and Ho): Strong hierarchy in the temperature dependence of the magnetic ordering in the multiple rare-earth sublattices

    SciTech Connect (OSTI)

    Ritter, C.; Provino, A.; Manfrinetti, P.; Pecharsky, V. K.; Gschneidner, Jr., K. A.; Dhar, S. K.

    2015-11-09

    In this study, the magnetic properties and magnetic structures of the R<sub>5sub>Ni>2sub>In>4sub> and the microfibrous R <sub>11sub>Ni>4sub>In>9sub> compounds with R = Tb and Ho have been examined using magnetization, heat capacity, and neutron diffraction data. Rare earth atoms occupy three and five symmetrically inequivalent rare earth sites in R<sub>5sub>Ni>2sub>In>4sub> and R <sub>11sub>Ni>4sub>In>9sub> compounds, respectively. As a result of the intra- and inter-magnetic sublattice interactions, the magnetic exchange interactions are different for various rare earth sites; this leads to a cascade of magnetic transitions with a strong hierarchy in the temperature dependence of the magnetic orderings.

  18. Regional Purchasing

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Regional Partnerships Regional Partnerships DOE's Regional Carbon Sequestration Partnerships Program DOE has created a network of seven Regional Carbon Sequestration Partnerships (RCSPs) to help develop the technology, infrastructure, and regulations to implement large-scale CO2 storage (also called carbon sequestration) in different regions and geologic formations within the Nation. Collectively, the seven RCSPs represent regions encompassing: 97 percent of coal-fired CO2 emissions; 97 percent

  19. Structural and magnetic phase transitions near optimal superconductivity in BaFe<sub>2sub>(As>1-xsub>Px)>2sub>

    SciTech Connect (OSTI)

    Hu, Ding; Lu, Xingye; Zhang, Wenliang; Luo, Huiqian; Li, Shiliang; Wang, Peipei; Chen, Genfu; Han, Fei; Banjara, Shree R.; Sapkota, A.; Kreyssig, A.; Goldman, A. I.; Yamani, Z.; Niedermayer, Christof; Skoulatos, Markos; Georgii, Robert; Keller, T.; Wang, Pengshuai; Yu, Weiqiang; Dai, Pengcheng

    2015-04-17

    In this study, we use nuclear magnetic resonance (NMR), high-resolution x-ray and neutron scattering to study structural and magnetic phase transitions in phosphorus-doped BaFe<sub>2sub>(As>1-xsub>Px)>2sub>. Thus, previous transport, NMR, specific heat, and magnetic penetration depth measurements have provided compelling evidence for the presence of a quantum critical point (QCP) near optimal superconductivity at x = 0.3. However, we show that the tetragonal-to-orthorhombic structural (T<sub>s>) and paramagnetic to antiferromagnetic (AF, T<sub>N>) transitions in BaFe<sub>2sub>(As>1-xsub>Px)>2sub> are always coupled and approach to T<sub>N> ≈ T<sub>s> ≥ T<sub>c> (≈ 29 K) for x = 0.29 before vanishing abruptly for x ≥ 0.3. These results suggest that AF order in BaFe<sub>2sub>(As>1-xsub>Px)>2sub> disappears in a weakly first order fashion near optimal superconductivity, much like the electron-doped iron pnictides with an avoided QCP.

  20. Evolution of competing magnetic order in the J<sub>eff>=1/2 insulating state of Sr<sub>2sub>Ir>1-xsub>RuxO>4sub>

    SciTech Connect (OSTI)

    Calder, Stuart A.; Kim, Jong-Woo; Cao, Guixin; Cantoni, Claudia; May, Andrew F; Cao, Huibo B.; Aczel, Adam A.; Matsuda, Masaaki; Choi, Yongseong; Haskel, Daniel; Sales, B. C.; Mandrus, David; Lumsden, Mark D.; Christianson, Andrew D.

    2015-10-27

    We investigate the magnetic properties of the series Sr<sub>2sub>Ir>1-xsub>RuxO>4sub> with neutron, resonant x-ray and magnetization measurements. The results indicate an evolution and coexistence of magnetic structures via a spin flop transition from ab-plane to c-axis collinear order as the 5d Ir4+ ions are replaced with an increasing concentration of 4d Ru4+ ions. The magnetic structures within the ordered regime of the phase diagram (x<0.3) are reported. Despite the changes in magnetic structure no alteration of the J<sub>eff>=1/2 ground state is observed. This behavior of Sr<sub>2sub>Ir>1-xsub>RuxO>4sub> is consistent with electronic phase separation and diverges from a standard scenario of hole doping. The role of lattice alterations with doping on the magnetic and insulating behavior is considered. Our results presented here provide insight into the magnetic insulating states in strong spin-orbit coupled materials and the role perturbations play in altering the behavior.

  1. trans-K<sub>3sub>[TcO>2sub>(CN)>4sub>

    SciTech Connect (OSTI)

    Chatterjee, Sayandev; Del Negro, Andrew S; Edwards, Matthew K; Twamley, Brendan; Krause, Jeanette A; Bryan, Samuel A

    2010-07-14

    The dioxotetracyanotechnetate anion, [TcO<sub>2sub>(CN)>4sub>]3-, of the title complex has octahedral symmetry. The technetium is located on a center of inversion and is bound by two oxygen atoms and four cyano ligands. The Tc=O bond distance of 1.7721 (12) Å is consistent with double bond character. The potassium cations [located on special (1/2,0,1) and general positions] reside in octahedral or tetrahedral environments; interionic K···O and K···N interactions occur in the 2.7877 (19)-2.8598 (15) Å range.

  2. Gold-rich R<sub>3sub>Au>7sub>Sn>3sub>: Establishing the interdependence between electronic features and physical properties

    SciTech Connect (OSTI)

    Provino, Alessia; Steinberg, Simon; Smetana, Volodymyr; Kulkarni, Ruta; Dhar, Sudesh K.; Manfrinetti, Pietro; Mudring, Anja -Verena

    2015-05-18

    Two new polar intermetallic compounds Y<sub>3sub>Au>7sub>Sn>3sub> (I) and Gd<sub>3sub>Au>7sub>Sn>3sub> (II) have been synthesized and their structures have been determined by single crystal X-ray diffraction (P6<sub>3sub>/m; Z = 2, a = 8.148(1)/8.185(3), and c = 9.394(2)/9.415(3) for I/II, respectively). They can formally be assigned to the Cu<sub>10sub>Sn>3sub> type and consist of parallel slabs of Sn centered, edge-sharing trigonal Au<sub>6sub> antiprisms connected through R<sub>3sub> (R = Y, Gd) triangles. Additional Au atoms reside in the centres of trigonal Au<sub>6sub> prisms forming Au@Au<sub>6sub> clusters with Au–Au distances of 2.906–2.960 Å, while the R–R contacts in the R<sub>3sub> groups are considerably larger than the sums of their metallic radii. These exclusive structural arrangements provide alluring systems to study the synergism between strongly correlated systems, particularly, those in the structure of (II), and extensive polar intermetallic contacts, which has been inspected by measurements of the magnetic properties, heat capacities and electrical conductivities of both compounds. Gd<sub>3sub>Au>7sub>Sn>3sub> shows an antiferromagnetic ordering at 13 K, while Y<sub>3sub>Au>7sub>Sn>3sub> is a Pauli paramagnet and a downward curvature in its electrical resistivity at about 1.9 K points to a superconducting transition. DFT-based band structure calculations on R<sub>3sub>Au>7sub>Sn>3sub> (R = Y, Gd) account for the results of the conductivity measurements and different spin ordering models of (II) provide conclusive hints about its magnetic structure. As a result, chemical bonding analyses of both compounds indicate that the vast majority of bonding originates from the heteroatomic Au–Gd and Au–Sn interactions, while homoatomic Au–Au bonding is evident within the Au@Au<sub>6sub> clusters.

  3. Spin glass in semiconducting KFe<sub>1.05sub>Ag>0.88sub>Te>2sub> single crystals

    SciTech Connect (OSTI)

    Ryu, H.; Lei, H.; Klobes, B.; Warren, J. B.; Hermann, R. P.; Petrovic, C.

    2015-05-26

    We report discovery of KFe<sub>1.05sub>Ag>0.88sub>Te>2sub> single crystals with semiconducting spin glass ground state. Composition and structure analysis suggest nearly stoichiometric I4/mmm space group but allow for the existence of vacancies, absent in long range semiconducting antiferromagnet KFe<sub>1.05sub>Ag>0.88sub>Te>2sub>. The subtle change in stoichometry in Fe/Ag sublattice changes magnetic ground state but not conductivity, giving further insight into the semiconducting gap mechanism.

  4. Two-phase convective CO<sub>2sub> dissolution in saline aquifers

    SciTech Connect (OSTI)

    Martinez, Mario J.; Hesse, Marc A.

    2016-01-01

    Geologic carbon storage in deep saline aquifers is a promising technology for reducing anthropogenic emissions into the atmosphere. Dissolution of injected CO<sub>2sub> into resident brines is one of the primary trapping mechanisms generally considered necessary to provide long-term storage security. Given that diffusion of CO<sub>2sub> in brine is woefully slow, convective dissolution, driven by a small increase in brine density with CO<sub>2sub> saturation, is considered to be the primary mechanism of dissolution trapping. Previous studies of convective dissolution have typically only considered the convective process in the single-phase region below the capillary transition zone and have either ignored the overlying two-phase region where dissolution actually takes place or replaced it with a virtual region with reduced or enhanced constant permeability. Our objective is to improve estimates of the long-term dissolution flux of CO<sub>2sub> into brine by including the capillary transition zone in two-phase model simulations. In the fully two-phase model, there is a capillary transition zone above the brine-saturated region over which the brine saturation decreases with increasing elevation. Our two-phase simulations show that the dissolution flux obtained by assuming a brine-saturated, single-phase porous region with a closed upper boundary is recovered in the limit of vanishing entry pressure and capillary transition zone. For typical finite entry pressures and capillary transition zone, however, convection currents penetrate into the two-phase region. As a result, this removes the mass transfer limitation of the diffusive boundary layer and enhances the convective dissolution flux of CO<sub>2sub> more than 3 times above the rate assuming single-phase conditions.

  5. A novel Bi-based phosphomolybdate photocatalyst K{sub 2}Bi(PO{sub 4})(MoO{sub 4}): Crystal structure, electronic structure and photocatalytic activity

    SciTech Connect (OSTI)

    Huang, Hongwei; Chen, Gong; Wang, Shuobo; Kang, Lei; Lin, Zheshuai; Zhang, Yihe

    2014-03-01

    Graphical abstract: - Highlights: A new type of phosphomolybdate K{sub 2}Bi(PO{sub 4})(MoO{sub 4}) photocatalyst was successfully synthesized. The products synthesized at 600 C were mainly composed of nano-cubes. The indirect band gap of K{sub 2}Bi(PO{sub 4})(MoO{sub 4}) has been determined to be 2.93 eV. K{sub 2}Bi(PO{sub 4})(MoO{sub 4}) synthesized at 600 C exhibits the highest photocatalytic activity. The electronic structure was calculated by density functional calculations. - Abstract: A novel phosphomolybdate photocatalyst K{sub 2}Bi(PO{sub 4})(MoO{sub 4}) has been successfully developed via a solid-state reaction. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), diffuse reflectance spectrum (DRS) and photoluminescence (PL) spectra. The photocatalytic activities of the samples prepared at different temperature were determined by the photooxidative decomposition of methylene blue (MB) in aqueous solution. The results revealed that K{sub 2}Bi(PO{sub 4})(MoO{sub 4}) can be used as an effective photocatalyst under UVvis irradiation and the nanocubes obtained at 600 C exhibits the highest photocatalytic activity. The photodegradation of MB by K{sub 2}Bi(PO{sub 4})(MoO{sub 4}) nanocrystals followed the first-order kinetics. Theoretical calculations on electronic structure confirmed the indirect optical transitions property in the absorption edge region of K{sub 2}Bi(PO{sub 4})(MoO{sub 4}), and the orbital constitutions of CB and VB were also analyzed.

  6. Synthesis and properties of new CdSe-AgI-As{sub 2}Se{sub 3} chalcogenide glasses

    SciTech Connect (OSTI)

    Kassem, M.; ULCO, LPCA, EAC CNRS 4493 F-59140 Dunkerque ; Le Coq, D.; Fourmentin, M.; Hindle, F.; Bokova, M.; Cuisset, A.; Masselin, P.; Bychkov, E.; ULCO, LPCA, EAC CNRS 4493 F-59140 Dunkerque

    2011-02-15

    Research highlights: {yields} Determination of the glass-forming region in the pseudo-ternary CdSe-AgI-As{sub 2}Se{sub 3} system. {yields} Characterization of macroscopic properties of the new CdSe-AgI-As{sub 2}Se{sub 3} glasses. {yields} Far infrared transmission of chalcogenide glasses. {yields} Characterization of the total conductivity of CdSe-AgI-As{sub 2}Se{sub 3} glasses. -- Abstract: The glass-forming region in the pseudo-ternary CdSe-AgI-As{sub 2}Se{sub 3} system was determined. Measurements including differential scanning calorimetry (DSC), density, and X-ray diffraction were performed. The effect resulting from the addition of CdSe or AgI has been highlighted by examining three series of different base glasses. The characteristic temperatures of the glass samples, including glass transition (T{sub g}), crystallisation (T{sub x}), and melting (T{sub m}) temperatures are reported and used to calculate their {Delta}T = T{sub x} - T{sub g} and their Hruby, H{sub r} = (T{sub x} - T{sub g})/(T{sub m} - T{sub x}), criteria. Evolution of the total electrical conductivity {sigma} and the room temperature conductivity {sigma}{sub 298} was also studied. The terahertz transparency domain in the 50-600 cm{sup -1} region was pointed for different chalcogenide glasses (ChGs) and the potential of the THz spectroscopy was suggested to obtain structural information on ChGs.

  7. Cationic disorder and Mn{sup 3+}/Mn{sup 4+} charge ordering in the B? and B? sites of Ca{sub 3}Mn{sub 2}NbO{sub 9} perovskite: a comparison with Ca{sub 3}Mn{sub 2}WO{sub 9}

    SciTech Connect (OSTI)

    Lpez, C.A.; Saleta, M.E.; Pedregosa, J.C.; Snchez, R.D.; Alonso, J.A.; and others

    2014-02-15

    We describe the preparation, crystal structure determination, magnetic and transport properties of two novel Mn-containing perovskites, with a different electronic configuration for Mn atoms located in B site. Ca{sub 3}Mn{sup 3+}{sub 2}WO{sub 9} and Ca{sub 3}Mn{sup 3+/4+}{sub 2}NbO{sub 9} were synthesized by standard ceramic procedures; the crystallographic structure was studied from X-ray powder diffraction (XRPD) and neutron powder diffraction (NPD). Both phases exhibit a monoclinic symmetry (S.G.: P2{sub 1}/n); Ca{sub 3}Mn{sub 2}WO{sub 9} presents a long-range ordering over the B sites, whereas Ca{sub 3}Mn{sub 2}NbO{sub 9} is strongly disordered. By in-situ NPD, the temperature evolution of the structure study presents an interesting evolution in the octahedral size (?MnO?) for Ca{sub 3}Mn{sub 2}NbO{sub 9}, driven by a charge ordering effect between Mn{sup 3+} and Mn{sup 4+} atoms, related to the anomaly observed in the transport measurements at T?160 K. Both materials present a magnetic order below T{sub C}=30 K and 40 K for W and Nb materials, respectively. The magneto-transport measurements display non-negligible magnetoresistance properties in the paramagnetic regime. - Graphical abstract: Comparison between the octahedron size and the magnetic behaviour for Ca{sub 3}Mn{sub 2}NbO{sub 9} in the temperature region where the charge and magnetic order occur. Display Omitted - Highlights: Two novel Mn-containing double perovskites were obtained by solid-state reactions. Both double perovskites are monoclinic (P2{sub 1}/n) determined by XRPD and NPD. Ca{sub 3}Mn{sub 2}WO{sub 9} contains Mn{sup 3+} while Ca{sub 3}Mn{sub 2}NbO{sub 9} includes mixed-valence cations Mn{sup 3+}/Mn{sup 4+}. Ca{sub 3}Mn{sub 2}NbO{sub 9} presents a charge-ordering effect between Mn{sup 3+} and Mn{sup 4+} evidenced by NPD. The magnetic and transport studies evidenced the charge ordering in Ca{sub 3}Mn{sub 2}NbO{sub 9}.

  8. Effect of neutron irradiation on defect evolution in Ti<sub>3sub>SiC>2sub> and Ti<sub>2sub>AlC

    SciTech Connect (OSTI)

    Tallman, Darin J.; He, Lingfeng; Garcia-Diaz, Brenda L.; Hoffman, Elizabeth N.; Kohse, Gordon; Sindelar, Robert L.; Barsoum, Michel W.

    2015-10-23

    Here, we report on the characterization of defects formed in polycrystalline Ti<sub>3sub>SiC>2sub> and Ti<sub>2sub>AlC samples exposed to neutron irradiation – up to 0.1 displacements per atom (dpa) at 350 ± 40 °C or 695 ± 25 °C, and up to 0.4 dpa at 350 ± 40 °C. Black spots are observed in both Ti<sub>3sub>SiC>2sub> and Ti<sub>2sub>AlC after irradiation to both 0.1 and 0.4 dpa at 350 °C. After irradiation to 0.1 dpa at 695 °C, small basal dislocation loops, with a Burgers vector of b = 1/2 [0001] are observed in both materials. At 9 ± 3 and 10 ± 5 nm, the loop diameters in the Ti<sub>3sub>SiC>2sub> and Ti<sub>2sub>AlC samples, respectively, were comparable. At 1 × 1023 loops/m3, the dislocation loop density in Ti<sub>2sub>AlC was ≈1.5 orders of magnitude greater than in Ti<sub>3sub>SiC>2sub>, at 3 x 1021 loops/m3. After irradiation at 350 °C, extensive microcracking was observed in Ti<sub>2sub>AlC, but not in Ti<sub>3sub>SiC>2sub>. The room temperature electrical resistivities increased as a function of neutron dose for all samples tested, and appear to saturate in the case of Ti<sub>3sub>SiC>2sub>. The MAX phases are unequivocally more neutron radiation tolerant than the impurity phases TiC and Al<sub>2sub>O>3sub>. Based on these results, Ti<sub>3sub>SiC>2sub> appears to be a more promising MAX phase candidate for high temperature nuclear applications than Ti<sub>2sub>AlC.

  9. The magnetic structure of EuCu<sub>2sub>Sb>2sub>

    SciTech Connect (OSTI)

    Ryan, D. H.; Cadogan, J. M.; Anand, V. K.; Johnston, D. C.; Flacau, R.

    2015-05-06

    Antiferromagnetic ordering of EuCu<sub>2sub>Sb>2sub> which forms in the tetragonal CaBe<sub>2sub>Ge>2sub>-type structure (space group P4/nmm #129) has been studied using neutron powder diffraction and 151Eu Mössbauer spectroscopy. The room temperature 151Eu isomer shift of –12.8(1) mm/s shows the Eu to be divalent, while the 151Eu hyperfine magnetic field (B<sub>hf>) reaches 28.7(2) T at 2.1 K, indicating a full Eu2+ magnetic moment. B<sub>hf>(T) follows a smooth $S=\\frac{7}{2}$ Brillouin function and yields an ordering temperature of 5.1(1) K. Refinement of the neutron diffraction data reveals a collinear A-type antiferromagnetic arrangement with the Eu moments perpendicular to the tetragonal c-axis. As a result, the refined Eu magnetic moment at 0.4 K is 7.08(15) μ<sub>B> which is the full free-ion moment expected for the Eu2+ ion with $S=\\frac{7}{2}$ and a spectroscopic splitting factor of g = 2.

  10. The magnetic structure of EuCu<sub>2sub>Sb>2sub>

    SciTech Connect (OSTI)

    Ryan, D. H.; Cadogan, J. M.; Anand, V. K.; Johnston, D. C.; Flacau, R.

    2015-05-06

    Antiferromagnetic ordering of EuCu<sub>2sub>Sb>2sub> which forms in the tetragonal CaBe<sub>2sub>Ge>2sub>-type structure (space group P4/nmm #129) has been studied using neutron powder diffraction and 151Eu Mssbauer spectroscopy. The room temperature 151Eu isomer shift of 12.8(1) mm/s shows the Eu to be divalent, while the 151Eu hyperfine magnetic field (B<sub>hf>) reaches 28.7(2) T at 2.1 K, indicating a full Eu2+ magnetic moment. B<sub>hf>(T) follows a smooth $S=\\frac{7}{2}$ Brillouin function and yields an ordering temperature of 5.1(1) K. Refinement of the neutron diffraction data reveals a collinear A-type antiferromagnetic arrangement with the Eu moments perpendicular to the tetragonal c-axis. As a result, the refined Eu magnetic moment at 0.4 K is 7.08(15) ?<sub>B> which is the full free-ion moment expected for the Eu2+ ion with $S=\\frac{7}{2}$ and a spectroscopic splitting factor of g = 2.

  11. Structural, electronic and magnetic properties of the series of double perovskites (Ca,Sr){sub 2?x}La{sub x}FeIrO{sub 6}

    SciTech Connect (OSTI)

    Bufaial, L.; Adriano, C.; Lora-Serrano, R.; Duque, J.G.S.; Mendona-Ferreira, L.; Rojas-Ayala, C.; Baggio-Saitovitch, E.; Bittar, E.M.; Pagliuso, P.G.

    2014-04-01

    Polycrystalline samples of the series of double perovskites Sr{sub 2?x}La{sub x}FeIrO{sub 6} were synthesized. Their structural, electronic and magnetic properties were investigated by X-ray powder diffraction, Mssbauer spectroscopy, magnetic susceptibility, heat capacity and electrical resistivity experiments. The compounds crystallize in a monoclinic structure and were fitted in space group P2{sub 1}/n, with a significant degree of Fe/Ir cationic disorder. As in Ca{sub 2?x}La{sub x}FeIrO{sub 6} the Sr-based system seems to evolve from an antiferromagnetic ground state for the end members (x=0.0 and x=2.0) to a ferrimagnetic order in the intermediate regions (x?1). Since Mssbauer spectra indicate that Fe valence remains 3+ with doping, this tendency of change in the nature of the microscopic interaction could be attributed to Ir valence changes, induced by La{sup 3+} electrical doping. Upon comparing both Ca and Sr series, Sr{sub 2?x}La{sub x}FeIrO{sub 6} is more structurally homogenous and presents higher magnetization and transition temperatures. Magnetic susceptibility measurements at high temperatures on Sr{sub 1.2}La{sub 0.8}FeIrO{sub 6} indicate a very high ferrimagnetic Curie temperature T{sub C}?700K. For the Sr{sub 2}FeIrO{sub 6} compound, electrical resistivity experiments under applied pressure suggest that this material might be a Mott insulator. - Graphical abstract: The Weiss constant as a function of La doping for the (Ca,Sr){sub 2?x}La{sub x}FeIrO{sub 6} series, indicating changes in FeIr magnetic coupling on both families. - Highlights: The double perovskite series (Ca,Sr){sub 2?x}La{sub x}FeIrO{sub 6} were synthesized. Changes in the Fe-Ir magnetic coupling due to La doping on both series. Evidence of high T{sub C} on Sr{sub 1.2}La{sub 0.8}FeIrO{sub 6}. Indication of Mott insulator behavior on Sr{sub 2}FeIrO{sub 6}.

  12. Magnetoelectric coupling tuned by competing single iron anisotropies in Mn<sub>1-xsub>NixTiO>3sub>

    SciTech Connect (OSTI)

    Chi, Songxue; Ye, Feng; Zhou, Haidong D.; Choi, E. S.; Hwang, J.; Cao, Huibo; Fernandez-Baca, Jaime A.

    2014-01-01

    A flop of electric polarization from P<sub>c> to P<sub>a> is observed in MnTiO<sub>3sub> as a spin flop transtion is triggered by a c-axis magnetic field, H<sub>c>=7 T. The critical magnetic field for P<sub>a> is significantly reduced in Mn<sub>1-xsub>NixTiO>3sub> (x=0.33). Neutron diffraction measurements revealed similar magnetic arrangements for the two compositions where the ordered spins couple antiferromagnetically with their nearest intra- and inter-planar neighbors. In the x=0.33 system, the single ion anisotropies of Mn2+ and Ni2+ compete and give rise to an additional spin reorientation transition at TR. A magnetic field, H<sub>c>, aligns the spins along c for T<sub>RN>. The rotation of the collinear spins away from the c-axis for Tsub>R> alters the magnetic point symmetry and gives rise to new ME susceptibility tensor form. Such linear ME response provides satisfactory explanation for behavior of field-induced electric polarization in both compositions. As the Ni content increases to x=0.5 and 0.68, the ME effect disappears as a new magnetic phase emerges.

  13. CAPITAL REGION

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    t 092007 15:28 FAX 301 903 4656 CAPITAL REGION 0 j002 SDOE F 1325.8 (8-89) EFG (0790) ... 092007 15:29 FAX 301 903 4656 CAPITAL REGION 003 * Implemented a more robust ...

  14. EIA - Annual Energy Outlook 2014 Early Release

    Annual Energy Outlook [U.S. Energy Information Administration (EIA)]

    Module Regions (NERC Region map) Table 73. Texas Regional Entity Table 74. Florida Reliability Coordinating Council Table 75. Midwest Reliability Council East Table 76. Midwest...

  15. Temperature, Oxygen, and Soot-Volume-Fraction Measurements in a Turbulent C<sub>2sub>H>4sub>-Fueled Jet Flame

    SciTech Connect (OSTI)

    Kearney, Sean P.; Guildenbecher, Daniel Robert; Winters, Caroline; Farias, Paul Abraham; Grasser, Thomas W.; Hewson, John C.

    2015-09-01

    We present a detailed set of measurements from a piloted, sooting, turbulent C <sub>2sub> H <sub>4 sub>- fueled diffusion flame. Hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (CARS) is used to monitor temperature and oxygen, while laser-induced incandescence (LII) is applied for imaging of the soot volume fraction in the challenging jet-flame environment at Reynolds number, Re = 20,000. Single-laser shot results are used to map the mean and rms statistics, as well as probability densities. LII data from the soot-growth region of the flame are used to benchmark the soot source term for one-dimensional turbulence (ODT) modeling of this turbulent flame. The ODT code is then used to predict temperature and oxygen fluctuations higher in the soot oxidation region higher in the flame.

  16. Synthesis, Structure, and Electrochemical Performance of High Capacity Li<sub>2sub>Cu>0.5sub>Ni>0.5sub>O>2sub> Cathodes

    SciTech Connect (OSTI)

    Ruther, Rose E; Zhou, Hui; Dhital, Chetan; Saravanan, Kuppan; Kercher, Andrew K.; Chen, Guoying; Huq, Ashfia; Delnick, Frank M.; Nanda, Jagjit

    2015-09-08

    Orthorhombic Li<sub>2sub>NiO>2sub>, Li<sub>2sub>CuO>2sub>, and solid solutions thereof have been studied as potential cathode materials for lithium-ion batteries due to their high theoretical capacity and relatively low cost. While neither endmember shows good cycling stability, the intermediate composition, Li<sub>2sub>Cu>0.5sub>Ni>0.5sub>O>2sub>, yields reasonably high reversible capacities. A new synthetic approach and detailed characterization of this phase and the parent Li<sub>2sub>CuO>2sub> are presented. The cycle life of Li<sub>2sub>Cu>0.5sub>Ni>0.5sub>O>2sub> is shown to depend critically on the voltage window. The formation of Cu1+ at low voltage and oxygen evolution at high voltage limit the electrochemical reversibility. In situ X-ray absorption spectroscopy (XAS), in situ Raman spectroscopy, and gas evolution measurements are used to follow the chemical and structural changes that occur as a function of cell voltage.

  17. Magnetic properties of bulk, and rapidly solidified nanostructured (Nd<sub>1-xsub>Cex)>2sub>Fe>14-ysub>Coy>B ribbons

    SciTech Connect (OSTI)

    Pathak, Arjun K.; Khan, M.; Gschneidner, Jr., K. A.; McCallum, R. W.; Zhou, L.; Sun, K.; Kramer, M. J.; Pecharsky, V. K.

    2015-11-06

    Magnetic properties of Ce and Co co-doped (Nd<sub>1-xsub>Cex)>2sub>Fe>14-ysub>Coy>B compounds have been investigated both in bulk polycrystalline and rapidly solidified nanostructured ribbon forms. For certain Ce concentrations the materials exhibit spin re-orientation transitions below 140 K. The Curie temperatures, saturation magnetizations, and other magnetic properties relevant for applications as permanent magnets are controlled by Ce and Co substitutions for Nd and Fe, respectively. Most importantly, the results show that Ce, Co co-doped compounds are excellent replacements for several Dy-based high performance permanent magnets (dysprosium is one of the critical elements and is, therefore, in short supply). As a result, the high temperature (>375 K) magnetic properties for Nd–Ce–Fe–Co–B based alloys show promise not only as a replacement for Dy-doped Nd<sub>2sub>Fe>14sub>B permanent magnets, but the new alloys also require significantly lower amounts of Nd, which too is the critical element that can be replaced by a more abundant Ce.

  18. Anisotropic swelling and microcracking of neutron irradiated Ti<sub>3sub>AlC>2sub>-Ti>5sub>Al>2sub>C>3sub> materials

    SciTech Connect (OSTI)

    Ang, Caen K.; Silva, Chinthaka M.; Shih, Chunghao Phillip; Koyanagi, Takaaki; Katoh, Yutai; Zinkle, Steven J.

    2015-12-17

    M<sub>n + 1sub>AXn> (MAX) phase materials based on Ti–Al–C have been irradiated at 400 °C (673 K) with fission neutrons to a fluence of 2 × 1025 n/m2 (E > 0.1 MeV), corresponding to ~ 2 displacements per atom (dpa). We report preliminary results of microcracking in the Al-containing MAX phase, which contained the phases Ti<sub>3sub>AlC>2sub> and Ti<sub>5sub>Al>2sub>C>3sub>. Equibiaxial ring-on-ring tests of irradiated coupons showed that samples retained 10% of pre-irradiated strength. Volumetric swelling of up to 4% was observed. Phase analysis and microscopy suggest that anisotropic lattice parameter swelling caused microcracking. Lastly, variants of titanium aluminum carbide may be unsuitable materials for irradiation at light water reactor-relevant temperatures.

  19. Polytypism, polymorphism, and superconductivity in TaSe<sub>2sub>–xTex>

    SciTech Connect (OSTI)

    Luo, Huixia; Xie, Weiwei; Tao, Jing; Inoue, Hiroyuki; Gyenis, András; Krizan, Jason W.; Yazdani, Ali; Zhu, Yimei; Cava, Robert Joseph

    2015-03-03

    Polymorphism in materials often leads to significantly different physical properties - the rutile and anatase polymorphs of TiO₂ are a prime example. Polytypism is a special type of polymorphism, occurring in layered materials when the geometry of a repeating structural layer is maintained but the layer stacking sequence of the overall crystal structure can be varied; SiC is an example of a material with many polytypes. Although polymorphs can have radically different physical properties, it is much rarer for polytypism to impact physical properties in a dramatic fashion. Here we study the effects of polytypism and polymorphism on the superconductivity of TaSe₂, one of the archetypal members of the large family of layered dichalcogenides. We show that it is possible to access 2 stable polytypes and 2 stable polymorphs in the TaSe<sub>2-xsub>Tex> solid solution, and find that the 3R polytype shows a superconducting transition temperature that is between 6 and 17 times higher than that of the much more commonly found 2H polytype. Thus, the reason for this dramatic change is not apparent, but we propose that it arises either from a remarkable dependence of T<sub>c> on subtle differences in the characteristics of the single layers present, or from a surprising effect of the layer stacking sequence on electronic properties that instead are expected to be dominated by the properties of a single layer in materials of this kind.

  20. Glass formation and the third harmonic generation of Cu{sub 2}SeGeSe{sub 2}As{sub 2}Se{sub 3} glasses

    SciTech Connect (OSTI)

    Reshak, A. H.; Klymovych, O. S.; Zmiy, O. F.; Myronchuk, G. L.; Zamuruyeva, O. V.; Alahmed, Z. A.; Chysk, J.; Bila, Jiri; Kamarudin, H.

    2014-10-14

    We have performed the investigation of the nonlinear optical properties namely the third harmonic generation (THG) of the glass-formation region in the Cu{sub 2}SeGeSe{sub 2}As{sub 2}Se{sub 3} system. The samples were synthesized by direct single-temperature method from high-purity elementary substances. We have found that the value of disorder parameter ? depends on the composition of the glassy alloys. The measurements show that increasing the Cu{sub 2}Se concentration leads to increased slope of the absorption edge, which may be explained by the decrease of the height of random potential relief for the electrons in the tails of the state density which border the band edges. A very sharp increase in the THG at low temperature was observed. Significant enhancement in THG was obtained with decreasing the energy gap, which agreed well with the nonlinear optical susceptibilities obtained from other glasses.

  1. New chalcogenide glasses in the CdTe-AgI-As{sub 2}Te{sub 3} system

    SciTech Connect (OSTI)

    Kassem, M.; Le Coq, D.; Boidin, R.; Bychkov, E.; ULCO, LPCA, EA 4493, F-59140 Dunkerque

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Determination of the glass-forming region in the pseudo-ternary CdTe-AgI-As{sub 2}Te{sub 3} system. Black-Right-Pointing-Pointer Characterization of macroscopic properties of the new CdTe-AgI-As{sub 2}Te{sub 3} glasses. Black-Right-Pointing-Pointer Characterization of the total conductivity of CdTe-AgI-As{sub 2}Te{sub 3} glasses. Black-Right-Pointing-Pointer Comparison between the selenide and telluride equivalent systems. -- Abstract: Chalcogenide glasses in the pseudo-ternary CdTe-AgI-As{sub 2}Te{sub 3} system were synthesized and the glass-forming range was determined. The maximum content of CdTe in this glass system was found to be equal to 15 mol.%. The macroscopic characterizations of samples have consisted in Differential Scanning Calorimetry, density, and X-ray diffraction measurements. The cadmium telluride addition does not generate any significant change in the glass transition temperature but the resistance of binary AgI-As{sub 2}Te{sub 3} glasses towards crystallisation is estimated to be decreasing on the base of {Delta}T = T{sub x} - T{sub g} parameter. The total electrical conductivity {sigma} was measured by complex impedance spectroscopy. First, the CdTe additions in the (AgI){sub 0.5}(As{sub 2}Te{sub 3}){sub 0.5} host glass, (CdTe){sub x}(AgI){sub 0.5-x/2}(As{sub 2}Te{sub 3}){sub 0.5-x/2} lead to a conductivity decrease at x {<=} 0.05. Then, the behaviour is reversed at 0.05 {<=} x {<=} 0.15. The obtained results are discussed by comparison with the equivalent selenide system.

  2. Area 2. Use Of Engineered Nanoparticle-Stabilized CO<sub>2sub> Foams To Improve Volumetric Sweep Of CO<sub>2sub> EOR Processes

    SciTech Connect (OSTI)

    DiCarlo, David; Huh, Chun; Johnston, Keith P.

    2015-01-31

    The goal of this project was to develop a new CO<sub>2 sub>injection enhanced oil recovery (CO<sub>2sub>-EOR) process using engineered nanoparticles with optimized surface coatings that has better volumetric sweep efficiency and a wider application range than conventional CO<sub>2sub>-EOR processes. The main objectives of this project were to (1) identify the characteristics of the optimal nanoparticles that generate extremely stable CO<sub>2sub> foams in situ in reservoir regions without oil; (2) develop a novel method of mobility control using “self-guiding” foams with smart nanoparticles; and (3) extend the applicability of the new method to reservoirs having a wide range of salinity, temperatures, and heterogeneity. Concurrent with our experimental effort to understand the foam generation and transport processes and foam-induced mobility reduction, we also developed mathematical models to explain the underlying processes and mechanisms that govern the fate of nanoparticle-stabilized CO<sub>2sub> foams in porous media and applied these models to (1) simulate the results of foam generation and transport experiments conducted in beadpack and sandstone core systems, (2) analyze CO<sub>2sub> injection data received from a field operator, and (3) aid with the design of a foam injection pilot test. Our simulator is applicable to near-injection well field-scale foam injection problems and accounts for the effects due to layered heterogeneity in permeability field, foam stabilizing agents effects, oil presence, and shear-thinning on the generation and transport of nanoparticle-stabilized C/W foams. This report presents the details of our experimental and numerical modeling work and outlines the highlights of our findings.

  3. Evolution of the spin-state transition with doping in La₁₋<sub>xSrx>CoO₃

    SciTech Connect (OSTI)

    Smith, R. X.; Hoch, M. J. R.; Moulton, W. G.; Kuhns, P. L.; Reyes, A. P.; Boebinger, G. S.; Zheng, H.; Mitchell, J. F.

    2012-08-20

    The thermally induced spin-state transition of Co³⁺ ions in the cobaltite LaCoO₃, found at temperatures in the range 40 to 120 K, has been the subject of extensive experimental and theoretical investigation. Much less is known about what happens to the spin-state transition in hole-doped La₁₋<sub>xSrx>CoO₃ (LSCO). The present ¹³⁹La NMR experiments show that spin-state transitions persist in nanoscale hole-poor regions of the inhomogeneous doped material. In fact, thermally induced spin-state transitions remain important for doping levels close to the metal-insulator critical concentration of x<sub>C>=0.17. This finding suggests that the unusual glassy behavior seen in doped LSCO for x<0.18 results from the interplay of spin-state transitions in hole-poor regions and ferromagnetism in hole-rich regions.

  4. Negative Ion Photoelectron Spectroscopy Confirms the Prediction that D-3h Carbontrioxide (CO<sub>3sub>) Has a Singlet Ground State

    SciTech Connect (OSTI)

    Hrovat, David; Hou, Gao-Lei; Chen, Bo; Wang, Xue B.; Borden, Weston

    2015-11-13

    The CO<sub>3sub> radical anion (CO<sub>3sub>•–) has been formed by electrospraying carbonate dianion (CO<sub>3sub>2–) into the gas phase. The negative ion photoelectron (NIPE) spectrum of CO<sub>3sub>•– shows that, unlike trimethylenemethane [C(CH<sub>2sub>)>3sub>], carbontrioxide (CO<sub>3sub>) has a singlet ground state. From the NIPE spectrum, the electron affinity of CO<sub>3sub> was determined to be EA = 4.06 ± 0.03 eV, and the singlet-triplet energy difference was found to be ΔEST = - 17.8 ± 0.9 kcal/mol. B3LYP, CCSD(T), and CASPT2 calculations all find that the two lowest triplet states of CO<sub>3sub> are very close in energy, a prediction that is confirmed by the relative intensities of the bands in the NIPE spectrum of CO<sub>3sub>•–. The 560 cm-1 vibrational progression, seen in the low energy region of the triplet band, enables the identification of the lowest, Jahn-Teller-distorted, triplet state as 3A<sub>1sub>, in which both unpaired electrons reside in σ MOs, rather than 3A<sub>2sub>, in which one unpaired electron occupies the b<sub>2sub> σ MO, and the other occupies the b<sub>1sub> π MO.

  5. Study of B??X<sub>u>l?? decays in BB? events tagged by a fully reconstructed B-meson decay and determination of |V<sub>ub>|

    SciTech Connect (OSTI)

    Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Milanes, D. A.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Brown, D. N.; Kerth, L. T.; Kolomensky, Yu. G.; Lynch, G.; Tackmann, K.; Koch, H.; Schroeder, T.; Asgeirsson, D. J.; Hearty, C.; Mattison, T. S.; McKenna, J. A.; Khan, A.; Blinov, V. E.; Buzykaev, A. R.; Druzhinin, V. P.; Golubev, V. B.; Kravchenko, E. A.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Todyshev, K. Yu.; Yushkov, A. N.; Bondioli, M.; Kirkby, D.; Lankford, A. J.; Mandelkern, M.; Stoker, D. P.; Atmacan, H.; Gary, J. W.; Liu, F.; Long, O.; Vitug, G. M.; Campagnari, C.; Hong, T. M.; Kovalskyi, D.; Richman, J. D.; West, C. A.; Eisner, A. M.; Kroseberg, J.; Lockman, W. S.; Martinez, A. J.; Schalk, T.; Schumm, B. A.; Seiden, A.; Cheng, C. H.; Doll, D. A.; Echenard, B.; Flood, K. T.; Hitlin, D. G.; Ongmongkolkul, P.; Porter, F. C.; Rakitin, A. Y.; Andreassen, R.; Dubrovin, M. S.; Huard, Z.; Meadows, B. T.; Sokoloff, M. D.; Sun, L.; Bloom, P. C.; Ford, W. T.; Gaz, A.; Nagel, M.; Nauenberg, U.; Smith, J. G.; Wagner, S. R.; Ayad, R.; Toki, W. H.; Spaan, B.; Kobel, M. J.; Schubert, K. R.; Schwierz, R.; Bernard, D.; Verderi, M.; Clark, P. J.; Playfer, S.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Cibinetto, G.; Fioravanti, E.; Garzia, I.; Luppi, E.; Munerato, M.; Negrini, M.; Petrella, A.; Piemontese, L.; Santoro, V.; Baldini-Ferroli, R.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Nicolaci, M.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Rama, M.; Zallo, A.; Contri, R.; Guido, E.; Lo Vetere, M.; Monge, M. R.; Passaggio, S.; Patrignani, C.; Robutti, E.; Bhuyan, B.; Prasad, V.; Lee, C. L.; Morii, M.; Edwards, A. J.; Adametz, A.; Marks, J.; Uwer, U.; Bernlochner, F. U.; Ebert, M.; Lacker, H. M.; Lueck, T.; Dauncey, P. D.; Tibbetts, M.; Behera, P. K.; Mallik, U.; Chen, C.; Cochran, J.; Meyer, W. T.; Prell, S.; Rosenberg, E. I.; Rubin, A. E.; Gritsan, A. V.; Guo, Z. J.; Arnaud, N.; Davier, M.; Grosdidier, G.; Le Diberder, F.; Lutz, A. M.; Malaescu, B.; Roudeau, P.; Schune, M. H.; Stocchi, A.; Wormser, G.; Lange, D. J.; Wright, D. M.; Bingham, I.; Chavez, C. A.; Coleman, J. P.; Fry, J. R.; Gabathuler, E.; Hutchcroft, D. E.; Payne, D. J.; Touramanis, C.; Bevan, A. J.; Di Lodovico, F.; Sacco, R.; Sigamani, M.; Cowan, G.; Brown, D. N.; Davis, C. L.; Denig, A. G.; Fritsch, M.; Gradl, W.; Hafner, A.; Prencipe, E.; Alwyn, K. E.; Bailey, D.; Barlow, R. J.; Jackson, G.; Lafferty, G. D.; Cenci, R.; Hamilton, B.; Jawahery, A.; Roberts, D. A.; Simi, G.; Dallapiccola, C.; Cowan, R.; Dujmic, D.; Sciolla, G.; Lindemann, D.; Patel, P. M.; Robertson, S. H.; Schram, M.; Biassoni, P.; Lazzaro, A.; Lombardo, V.; Neri, N.; Palombo, F.; Stracka, S.; Cremaldi, L.; Godang, R.; Kroeger, R.; Sonnek, P.; Summers, D. J.; Nguyen, X.; Taras, P.; De Nardo, G.; Monorchio, D.; Onorato, G.; Sciacca, C.; Raven, G.; Snoek, H. L.; Jessop, C. P.; Knoepfel, K. J.; LoSecco, J. M.; Wang, W. F.; Honscheid, K.; Kass, R.; Brau, J.; Frey, R.; Sinev, N. B.; Strom, D.; Torrence, E.; Feltresi, E.; Gagliardi, N.; Margoni, M.; Morandin, M.; Posocco, M.; Rotondo, M.; Simonetto, F.; Stroili, R.; Ben-Haim, E.; Bomben, M.; Bonneaud, G. R.; Briand, H.; Calderini, G.; Chauveau, J.; Hamon, O.; Leruste, Ph.; Marchiori, G.; Ocariz, J.; Sitt, S.; Biasini, M.; Manoni, E.; Pacetti, S.; Rossi, A.; Angelini, C.; Batignani, G.; Bettarini, S.; Carpinelli, M.; Casarosa, G.; Cervelli, A.; Forti, F.; Giorgi, M. A.; Lusiani, A.; Oberhof, B.; Paoloni, E.; Perez, A.; Rizzo, G.; Walsh, J. J.; Lopes Pegna, D.; Lu, C.; Olsen, J.; Smith, A. J. S.; Telnov, A. V.; Anulli, F.; Cavoto, G.; Faccini, R.; Ferrarotto, F.; Ferroni, F.; Gaspero, M.; Li Gioi, L.; Mazzoni, M. A.; Piredda, G.; Bnger, C.; Grnberg, O.; Hartmann, T.; Leddig, T.; Schrder, H.; Waldi, R.; Adye, T.; Olaiya, E. O.; Wilson, F. F.; Emery, S.; Hamel de Monchenault, G.; Vasseur, G.; Yche, Ch.; Aston, D.; Bard, D. J.; Bartoldus, R.; Cartaro, C.; Convery, M. R.; Dorfan, J.; Dubois-Felsmann, G. P.; Dunwoodie, W.; Field, R. C.; Franco Sevilla, M.; Fulsom, B. G.; Gabareen, A. M.; Graham, M. T.; Grenier, P.; Hast, C.; Innes, W. R.; Kelsey, M. H.; Kim, H.; Kim, P.; Kocian, M. L.; Leith, D. W. G. S.; Lewis, P.; Li, S.; Lindquist, B.; Luitz, S.; Luth, V.; Lynch, H. L.; MacFarlane, D. B.; Muller, D. R.; Neal, H.; Nelson, S.; Ofte, I.; Perl, M.; Pulliam, T.; Ratcliff, B. N.; Roodman, A.; Salnikov, A. A.; Schindler, R. H.; Snyder, A.; Su, D.; Sullivan, M. K.; Vavra, J.; Wagner, A. P.; Weaver, M.; Wisniewski, W. J.; Wittgen, M.; Wright, D. H.; Wulsin, H. W.; Yarritu, A. K.; Young, C. C.; Ziegler, V.; Park, W.; Purohit, M. V.; White, R. M.; Wilson, J. R.; Randle-Conde, A.; Sekula, S. J.; Bellis, M.; Benitez, J. F.; Burchat, P. R.

    2012-08-07

    We report measurements of partial branching fractions for inclusive charmless semileptonic B decays B?X<sub>u>l? and the determination of the CabibboKobayashiMaskawa (CKM) matrix element |V<sub>ub>|. The analysis is based on a sample of 46710? ?(4S)?BB decays recorded with the BABAR detector at the PEP-II e?e? storage rings. We select events in which the decay of one of the B mesons is fully reconstructed and an electron or a muon signals the semileptonic decay of the other B meson. We measure partial branching fractions ?B in several restricted regions of phase space and determine the CKM element |V<sub>ub>| based on different QCD predictions. For decays with a charged lepton momentum p*<sub>l>>1.0 GeV in the B meson rest frame, we obtain ?B=(1.800.13stat0.15sys0.02theo)10? from a fit to the two-dimensional M<sub>X>-q distribution. Here, M<sub>X> refers to the invariant mass of the final state hadron X and q is the invariant mass squared of the charged lepton and neutrino. From this measurement we extract |V<sub>ub>|=(4.330.24<sub>exp>?0.15<sub>theo>)10? as the arithmetic average of four results obtained from four different QCD predictions of the partial rate. We separately determine partial branching fractions for B0 and B? decays and derive a limit on the isospin breaking in B?X<sub>u>l? decays.

  6. Evaluating sub-national building-energy efficiency policy options under uncertainty: Efficient sensitivity testing of alternative climate, technolgical, and socioeconomic futures in a regional intergrated-assessment model.

    SciTech Connect (OSTI)

    Scott, Michael J.; Daly, Don S.; Zhou, Yuyu; Rice, Jennie S.; Patel, Pralit L.; McJeon, Haewon C.; Kyle, G. Page; Kim, Son H.; Eom, Jiyong; Clarke, Leon E.

    2014-05-01

    Improving the energy efficiency of the building stock, commercial equipment and household appliances can have a major impact on energy use, carbon emissions, and building services. Subnational regions such as U.S. states wish to increase their energy efficiency, reduce carbon emissions or adapt to climate change. Evaluating subnational policies to reduce energy use and emissions is difficult because of the uncertainties in socioeconomic factors, technology performance and cost, and energy and climate policies. Climate change may undercut such policies. Assessing these uncertainties can be a significant modeling and computation burden. As part of this uncertainty assessment, this paper demonstrates how a decision-focused sensitivity analysis strategy using fractional factorial methods can be applied to reveal the important drivers for detailed uncertainty analysis.

  7. Measurement of the B<sub>-c>meson lifetime in the decay B<sub>-c>?J/???

    SciTech Connect (OSTI)

    Aaltonen, T.; lvarez Gonzlez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Bae, T.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartos, P.; Bauce, M.; Bedeschi, F.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Bhatti, A.; Bisello, D.; Bizjak, I.; Bland, K. R.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brigliadori, L.; Bromberg, C.; Brucken, E.; Budagov, J.; Budd, H. S.; Burkett, K.; Busetto, G.; Bussey, P.; Buzatu, A.; Calamba, A.; Calancha, C.; Camarda, S.; Campanelli, M.; Campbell, M.; Canelli, F.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Carron, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Chlebana, F.; Cho, K.; Chokheli, D.; Chung, W. H.; Chung, Y. S.; Ciocci, M. A.; Clark, A.; Clarke, C.; Compostella, G.; Convery, M. E.; Conway, J.; Corbo, M.; Cordelli, M.; Cox, C. A.; Cox, D. J.; Crescioli, F.; Cuevas, J.; Culbertson, R.; Dagenhart, D.; dAscenzo, N.; Datta, M.; de Barbaro, P.; DellOrso, M.; Demortier, L.; Deninno, M.; Devoto, F.; dErrico, M.; Di Canto, A.; Di Ruzza, B.; Dittmann, J. R.; DOnofrio, M.; Donati, S.; Dong, P.; Dorigo, M.; Dorigo, T.; Ebina, K.; Elagin, A.; Eppig, A.; Erbacher, R.; Errede, S.; Ershaidat, N.; Eusebi, R.; Farrington, S.; Feindt, M.; Fernandez, J. P.; Field, R.; Flanagan, G.; Forrest, R.; Frank, M. J.; Franklin, M.; Freeman, J. C.; Funakoshi, Y.; Furic, I.; Gallinaro, M.; Garcia, J. E.; Garfinkel, A. F.; Garosi, P.; Gerberich, H.; Gerchtein, E.; Giagu, S.; Giakoumopoulou, V.; Giannetti, P.; Gibson, K.; Ginsburg, C. M.; Giokaris, N.; Giromini, P.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldin, D.; Goldschmidt, N.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; Gonzlez, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Grinstein, S.; Grosso-Pilcher, C.; Group, R. C.; Guimaraes da Costa, J.; Hahn, S. R.; Halkiadakis, E.; Hamaguchi, A.; Han, J. Y.; Happacher, F.; Hara, K.; Hare, D.; Hare, M.; Harr, R. F.; Hatakeyama, K.; Hays, C.; Heck, M.; Heinrich, J.; Herndon, M.; Hewamanage, S.; Hocker, A.; Hopkins, W.; Horn, D.; Hou, S.; Hughes, R. E.; Hurwitz, M.; Husemann, U.; Hussain, N.; Hussein, M.; Huston, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E. J.; Jindariani, S.; Jones, M.; Joo, K. K.; Jun, S. Y.; Junk, T. R.; Kamon, T.; Karchin, P. E.; Kasmi, A.; Kato, Y.; Ketchum, W.; Keung, J.; Khotilovich, V.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, J. E.; Kim, M. J.; Kim, S. B.; Kim, S. H.; Kim, Y. K.; Kim, Y. J.; Kimura, N.; Kirby, M.; Klimenko, S.; Knoepfel, K.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Kotwal, A. V.; Kreps, M.; Kroll, J.; Krop, D.; Kruse, M.; Krutelyov, V.; Kuhr, T.; Kurata, M.; Kwang, S.; Laasanen, A. T.; Lami, S.; Lammel, S.; Lancaster, M.; Lander, R. L.; Lannon, K.; Lath, A.; Latino, G.; LeCompte, T.; Lee, E.; Lee, H. S.; Lee, J. S.; Lee, S. W.; Leo, S.; Leone, S.; Lewis, J. D.; Limosani, A.; Lin, C.-J.; Lindgren, M.; Lipeles, E.; Lister, A.; Litvintsev, D. O.; Liu, C.; Liu, H.; Liu, Q.; Liu, T.; Lockwitz, S.; Loginov, A.; Lucchesi, D.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lys, J.; Lysak, R.; Madrak, R.; Maeshima, K.; Maestro, P.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Margaroli, F.; Marino, C.; Martnez, M.; Mastrandrea, P.; Matera, K.; Mattson, M. E.; Mazzacane, A.; Mazzanti, P.; McFarland, K. S.; McIntyre, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Mesropian, C.; Miao, T.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Mondragon, M. N.; Moon, C. S.; Moore, R.; Morello, M. J.; Morlock, J.; Movilla Fernandez, P.; Mukherjee, A.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nakano, I.; Napier, A.; Nett, J.; Neu, C.; Neubauer, M. S.; Nielsen, J.; Nodulman, L.; Noh, S. Y.; Norniella, O.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Ortolan, L.; Pagan Griso, S.; Pagliarone, C.; Palencia, E.; Papadimitriou, V.; Paramonov, A. A.; Patrick, J.; Pauletta, G.; Paulini, M.; Paus, C.; Pellett, D. E.; Penzo, A.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.; Pondrom, L.; Poprocki, S.; Potamianos, K.; Prokoshin, F.; Pranko, A.; Ptohos, F.; Punzi, G.; Rahaman, A.; Ramakrishnan, V.; Ranjan, N.; Redondo, I.; Renton, P.; Rescigno, M.; Riddick, T.; Rimondi, F.; Ristori, L.; Robson, A.; Rodrigo, T.; Rodriguez, T.; Rogers, E.; Rolli, S.; Roser, R.; Ruffini, F.; Ruiz, A.; Russ, J.; Rusu, V.; Safonov, A.; Sakumoto, W. K.

    2013-01-01

    The lifetime of the B<sub>-c> meson is measured using 272 exclusive B<sub>-c>?J/?(?????)?? decays reconstructed in data from proton-antiproton collisions corresponding to an integrated luminosity of 6.7 fb? recorded by the CDF II detector at the Fermilab Tevatron. The lifetime of the B<sub>-c>meson is measured to be <sub>?(B-c>)=0.4520.048(stat)0.027(syst) ps. This is the first measurement of the B<sub>-c> meson lifetime in a fully reconstructed hadronic channel, and it agrees with previous results and has comparable precision.

  8. Synthesis, structural, magnetic and electrical properties of Co{sub 1?x}Zn{sub x}Fe{sub 2}O{sub 4} (x = 0.0, 0.2) nanoparticles

    SciTech Connect (OSTI)

    Deligz, H.; Baykal, A.; Toprak, M.S.; Yildirim Beyazit University, Dept of Materials Science and Engineering, Ulus, Ankara ; Tanr?verdi, E.E.; Durmus, Z.; Szeri, H.

    2013-02-15

    Graphical abstract: The variations of imaginary part of dielectric permittivity (??) of TEG@Co{sub 1?x}Zn{sub x}Fe{sub 2}O{sub 4} nanocomposite as a function of temperature and frequency for (A) x = 0.0 and (B) x = 0.2. Display Omitted Highlights: ? Nearly monodisperse Zn{sub x}Co{sub 1?x}Fe{sub 2}O{sub 4} nanocomposite were prepared via hydrothermal method. ? The ac conductivity showed a temperature dependent behavior at low frequencies. ? dc conductivity of Co{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} nanoparticle are found to obey the Arrhenius plot. ? Also these materials may be used in electronic devices and microwave devices. -- Abstract: Co{sub 1?x}Zn{sub x}Fe{sub 2}O{sub 4} spinel nanoparticles with Zn concentrations of x = 0.0, 0.2 were prepared by a hydrothermal route in the presence of triethylene glycol (TEG). The structural, magnetic, electrical and dielectric properties of the prepared nanoparticles were studied. The XRD results confirmed the formation of single spinel ferrite structure with crystallite size 9 and 10 nm for x = 0.0 and 0.2 compositions respectively. The lattice parameter (a) increased with increasing Zn concentration. Temperature and frequency dependent electrical and dielectric properties of the prepared ferrites have also been investigated. Our findings show that overall conductivity of Co{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} nanoparticle is lower than that of CoFe{sub 2}O{sub 4} and roughly in the range of 10{sup ?11}10{sup ?7} S cm{sup ?1} depending strongly temperature and frequency owing to the formation of stable electric bonds between the Zn{sup 2+} and Fe{sup 2+} ions, which localizes Fe{sup 2+} charge carriers. The ac conductivity showed a temperature dependent behavior at low frequencies and temperature independent behavior at high frequencies, which is an indication of ionic conductivity. dc conductivity of Co{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} nanoparticle are found to obey the Arrhenius plot and can be classified into two regions over with activation energy of 0.113 and 0.163 eV in the ranges of 2040 C and 70120 C, respectively when CoFe{sub 2}O{sub 4} has an activation energy of 0.245 eV.

  9. Temperature dependence of the coercive force in Nd sub 4 Fe sub 77 B sub 19

    SciTech Connect (OSTI)

    Eckert, D.; Muller, K.H.; Handstein, A.; Schneider, J. ); Grossinger, R.; Krewenka, R. )

    1990-09-01

    The temperature dependence of coercivity {sub J}H{sub c} of Fe{sub 3}B-based Nd{sub 4}Fe{sub 77}B{sub 19} permanent magnetic materials is analysed. The coercivity of these melt-spun materials vanishes above the Curie temperature of the minor phase Nd{sub 2}Fe{sub 14}B. As well as melt-spun Nd-rich magnets, Nd{sub 4}Fe{sub 77}B{sub 19} magnets show a maximum in the {sub J}H{sub c} versus T curve at low temperatures. The coercivity of these melt-spun materials has a smaller temperature coefficient than sintered Nd-rich NdFeB magnets. The relation of the observed T- dependence of {sub J}H{sub c}, to the anisotropy field H{sub A}(T) of Nd{sub 2}Fe{sub 14}B is discussed.

  10. Analysis of the CO<sub>2sub>-H>2sub>O Chemisorption in Lithium Silicates at Low Temperatures (30-80 C)

    SciTech Connect (OSTI)

    Alcantar-Vazquez, Brenda; Pfeiffer, Heriberto; Daz Herrera, Pablo R.; Gonzalez, Alejandro Barrera; Duan, Yuhua

    2015-01-01

    Li<sub>8sub>SiO>6sub> and Li<sub>4sub>SiO>4sub> were synthesized by a solid-state reaction. Then, dynamic and isothermal thermogravimetric water vapor sorption experiments were performed using two carrier gases: N<sub>2sub> and CO<sub>2sub>. Initially, the Li<sub>8sub>SiO>6sub>-H>2sub>O-(N>2sub> or CO<sub>2sub>) systems were analyzed. It was evidenced that Li<sub>8sub>SiO>6sub> can trap water physically and chemically, producing Li-OH superficial species. When CO<sub>2sub> was used as the carrier gas, Li<sub>8sub>SiO>6sub> continued chemisorbing H<sub>2sub>O but CO<sub>2sub> was trapped as well, forming Li<sub>2sub>CO>3sub> and Li<sub>4sub>SiO>4sub> as secondary phases. On the basis of these results, the Li<sub>4sub>SiO>4sub>-H>2sub>O-CO>2sub> system was also analyzed. The experimental results and different theoretical thermodynamic calculations confirmed that Li<sub>8sub>SiO>6sub> can chemisorb 2 moles of CO<sub>2sub> per mole of ceramic at a low temperature range (30-80 C). Finally, different CO<sub>2sub> chemisorption kinetic experiments were performed to analyze and quantify the trapped CO<sub>2sub>.

  11. High-Temperature Thermoelectric Properties of the Solid-Solution Zintl Phase Eu<sub>11sub>Cd>6sub>Sb>12-xsub>Asx> (x < 3)

    SciTech Connect (OSTI)

    Kazem, Nasrin; Xie, Weiwei; Ohno, Saneyuki; Zevalkink, Alexandra; Miller, Gordon J.; Snyder, G. Jeffrey; Kauzlarich, Susan M.

    2014-02-20

    Zintl phases are compounds that have shown promise for thermoelectric applications. The title solid–solution Zintl compounds were prepared from the elements as single crystals using a tin flux for compositions x = 0, 1, 2, and 3. Eu<sub>11sub>Cd>6sub>Sb>12–xsub>Asx> (x < 3) crystallize isostructurally in the centrosymmetric monoclinic space group C2/m (no. 12, Z = 2) as the Sr<sub>11sub>Cd>6sub>Sb>12sub> structure type (Pearson symbol mC58). Efforts to make the As compositions for x exceeding ~3 resulted in structures other than the Sr<sub>11sub>Cd>6sub>Sb>12sub> structure type. Single-crystal X-ray diffraction indicates that As does not randomly substitute for Sb in the structure but is site specific for each composition. The amount of As determined by structural refinement was verified by electron microprobe analysis. Electronic structures and energies calculated for various model structures of Eu<sub>11sub>Cd>6sub>Sb>10sub>As>2sub> (x = 2) indicated that the preferred As substitution pattern involves a mixture of three of the six pnicogen sites in the asymmetric unit. In addition, As substitution at the Pn4 site opens an energy gap at the Fermi level, whereas substitution at the other five pnicogen sites remains semimetallic with a pseudo gap. Thermoelectric properties of these compounds were measured on hot-pressed, fully densified pellets. Samples show exceptionally low lattice thermal conductivities from room temperature to 775 K: 0.78–0.49 W/mK for x = 0; 0.72–0.53 W/mK for x = 1; and 0.70–0.56 W/mK for x = 2. Eu<sub>11sub>Cd>6sub>Sb>12sub> shows a high p-type Seebeck coefficient (from +118 to 153 μ V/K) but also high electrical resistivity (6.8 to 12.8 mΩ·cm). The value of zT reaches 0.23 at 774 K. The properties of Eu<sub>11sub>Cd>6sub>Sb>12–xsub>Asx> are interpreted in discussion with the As site substitution.

  12. Synthesis, crystal structure investigation and magnetism of the complex metal-rich boride series Cr{sub x}(Rh{sub 1-y}Ru{sub y}){sub 7-x}B{sub 3} (x=0.88-1; y=0-1) with Th{sub 7}Fe{sub 3}-type structure

    SciTech Connect (OSTI)

    Misse, Patrick R.N.; Mbarki, Mohammed; Fokwa, Boniface P.T.

    2012-08-15

    Powder samples and single crystals of the new complex boride series Cr{sub x}(Rh{sub 1-y}Ru{sub y}){sub 7-x}B{sub 3} (x=0.88-1; y=0-1) have been synthesized by arc-melting the elements under purified argon atmosphere on a water-cooled copper crucible. The products, which have metallic luster, were structurally characterized by single-crystal and powder X-ray diffraction as well as EDX measurements. Within the whole solid solution range the hexagonal Th{sub 7}Fe{sub 3} structure type (space group P6{sub 3}mc, no. 186, Z=2) was identified. Single-crystal structure refinement results indicate the presence of chromium at two sites (6c and 2b) of the available three metal Wyckoff sites, with a pronounced preference for the 6c site. An unexpected Rh/Ru site preference was found in the Ru-rich region only, leading to two different magnetic behaviors in the solid solution: The Rh-rich region shows a temperature-independent (Pauli) paramagnetism whereas an additional temperature-dependent paramagnetic component is found in the Ru-rich region. - Graphical abstract: The new complex boride series Cr{sub x}(Rh{sub 1-y}Ru{sub y}){sub 7-x}B{sub 3} (x=0.88-1; y=0-1) has been synthesized by arc melting the elements under purified argon atmosphere. Beside the 3d/4d site preference within the whole solid solution, an unexpected Rh/Ru site preference was found in the Ru-rich region only, leading to two different magnetic behaviors: The Rh-rich region shows a temperature-independent (Pauli) paramagnetism whereas an additional temperature-dependent paramagnetic component is found in the Ru-rich region. Highlights: Black-Right-Pointing-Pointer Synthesis of a new boride series fulfilling Vegard Acute-Accent s rule. Black-Right-Pointing-Pointer 3d/4d site preference. Black-Right-Pointing-Pointer Unexpected Ru/Rh site preference. Black-Right-Pointing-Pointer Rh-rich region is Pauli paramagnetic. Black-Right-Pointing-Pointer Ru-rich region is Pauli and temperature-dependent paramagnetic.

  13. Highly dispersed SiO<sub>x/Al>2sub>O>3sub> catalysts illuminate the reactivity of isolated silanol sites

    SciTech Connect (OSTI)

    Mouat, Aidan R.; George, Cassandra; Kobayashi, Takeshi; Pruski, Marek; van?Duyne, Richard P.; Marks, Tobin J.; Stair, Peter C.

    2015-09-23

    The reaction of ?-alumina with tetraethylorthosilicate (TEOS) vapor at low temperatures selectively yields monomeric SiO<sub>x> species on the alumina surface. These isolated (-AlO)<sub>3sub>Si(OH) sites are characterized by PXRD, XPS, DRIFTS of adsorbed NH<sub>3sub>, CO, and pyridine, and 29Si and 27Al DNP-enhanced solid-state NMR spectroscopy. The formation of isolated sites suggests that TEOS reacts preferentially at strong Lewis acid sites on the ?-Al<sub>2sub>O>3sub> surface, functionalizing the surface with mild Brnsted acid sites. As a result, for liquid-phase catalytic cyclohexanol dehydration, these SiO<sub>x> sites exhibit up to 3.5-fold higher specific activity than the parent alumina with identical selectivity.

  14. Observation of the wavepacket dynamics on the {sup 1}B{sub 2}({sup 1}?{sub u}{sup +}) state of CS{sub 2} by sub-20 fs photoelectron imaging using 159 nm probe pulses

    SciTech Connect (OSTI)

    Spesyvtsev, R.; Horio, T.; Suzuki, Y.-I.; Suzuki, T.

    2015-02-21

    The wavepacket dynamics of CS{sub 2} after photoexcitation to the {sup 1}B{sub 2}({sup 1}?{sub u}{sup +}) state at 198 nm are studied by time-resolved photoelectron imaging using sub-20 fs 159 nm pulses, which enable single photon ionization from the entire region of the {sup 1}B{sub 2} potential energy surface. The time-energy map of the photoelectron intensity reveals vibrational motions along the symmetric stretching and bending coordinates. The time-energy map of the photoelectron anisotropy parameter exhibits time-evolution within single oscillation periods of the ?{sub 1} and ?{sub 2} modes, which is attributed to variation of the excited state electronic character along these vibrational coordinates. The initially populated {sup 1}B{sub 2} state evolves with two time constants of 107 and 394 fs.

  15. Energy Efficiency in Western Utility Resource Plans: Impacts onRegional Resources Assessment and Support for WGA Policies

    SciTech Connect (OSTI)

    Hopper, Nicole; Goldman, Charles; Schlegal, Jeff

    2006-08-01

    In the aftermath of the consumer price shocks and short-term power shortages of the 2000-01 electricity crisis, policymakers and regulators in Western states are placing increased emphasis on integrated resource planning (IRP), resource adequacy and assessment and a diversified portfolio of resources to meet the needs of electricity consumers. In some states, this has led to a resurgence in state and utility commitments to energy efficiency. Increasing interest in acquiring energy efficiency as a power-system resource is also driven by the desire to dampen high growth rates in electricity demand in some Western states, rapid increases in natural gas prices, concerns about the environmental impacts of electricity generation (e.g. water consumption by power plants, air quality), and the potential of energy efficiency to provide utility bill savings for households and businesses (WGA CDEAC 2006). Recognizing the cost-competitiveness and environmental benefits of energy efficiency, the Western Governor's Association (WGA) has set a high priority for energy efficiency, establishing a goal of reducing projected electricity demand by 20% across the West by 2020 in a policy resolution on Clean and Diversified Energy for the West (WGA 2004). Nationally, the need for improved tracking of demand-side resources in load forecasting is formalized in the North American Electric Reliability Council (NERC)'s recently adopted reliability standards, which utilities and regional reliability organizations will need to comply with (NERC 2005a and 2005b). In this study, we examine the treatment of energy efficiency in recent resource plans issued by fourteen investor-owned utilities (IOUs) in the Western United States and Canada. The goals of this study are to: (1) summarize energy-efficiency resources as represented in a large sample of recent resource plans prepared by Western utilities and identify key issues; (2) evaluate the extent to which the information provided in current resource plans can be used to support region-wide resource assessment and tracking of state/utility progress in meeting the WGA's energy-efficiency goals (WGA 2004); and (3) offer recommendations on information and documentation of energy-efficiency resources that should be included in future resource plans to facilitate comparative review and regional coordination. The scope of this report covers projected electric end-use efficiency investments reported in all Western utility resource plans that were publicly available as of February 2006. While a few utilities included additional demand-side resources, such as demand response, in their plans, we do not report that information. However, many of the issues and recommendations in reference to energy efficiency in this report are relevant to other demand-side resources as well. This report is organized as follows. Section 2 outlines the data sources and approach used in this study and conceptualizes methods and metrics for tracking energy-efficiency resources over time. Section 3 presents results from the review of the utility resource plans. Important issues encountered in reviewing the resource plans are discussed in section 4. Finally, section 5 concludes with recommendations for improving the tracking and reporting of energy efficiency in forthcoming resource plans.

  16. Structural phase transitions in Bi<sub>2sub>Se>3sub> under high pressure

    SciTech Connect (OSTI)

    Yu, Zhenhai; Gu, Genda; Wang, Lin; Hu, Qingyang; Zhao, Jinggeng; Yan, Shuai; Yang, Ke; Sinogeikin, Stanislav; Mao, Ho -kwang

    2015-11-02

    Raman spectroscopy and angle dispersive X-ray diffraction (XRD) experiments of bismuth selenide (Bi<sub>2sub>Se>3sub>) have been carried out to pressures of 35.6 and 81.2 GPa, respectively, to explore its pressure-induced phase transformation. The experiments indicate that a progressive structural evolution occurs from an ambient rhombohedra phase (Space group (SG): R-3m) to monoclinic phase (SG: C2/m) and eventually to a high pressure body-centered tetragonal phase (SG: I4/mmm). Evidenced by our XRD data up to 81.2 GPa, the Bi<sub>2sub>Se>3sub> crystallizes into body-centered tetragonal structures rather than the recently reported disordered body-centered cubic (BCC) phase. Furthermore, first principles theoretical calculations favor the viewpoint that the I4/mmm phase Bi<sub>2sub>Se>3sub> can be stabilized under high pressure (>30 GPa). Remarkably, the Raman spectra of Bi<sub>2sub>Se>3sub> from this work (two independent runs) are still Raman active up to ~35 GPa. Furthermore, it is worthy to note that the disordered BCC phase at 27.8 GPa is not observed here. The remarkable difference in atomic radii of Bi and Se in Bi<sub>2sub>Se>3sub> may explain why Bi<sub>2sub>Se>3sub> shows different structural behavior than isocompounds Bi<sub>2sub>Te>3sub> and Sb<sub>2sub>Te>3sub>.

  17. Effects of Mg doping on the remarkably enhanced electrochemical performance of Na<sub>3sub>V>2sub>(PO>4sub>)>3sub> cathode materials for sodium ion batteries

    SciTech Connect (OSTI)

    Li, Hui; Yu, Xiqian; Bai, Ying; Wu, Feng; Wu, Chuan; Liu, Liang-Yu; Yang, Xiao-Qing

    2015-01-01

    Na<sub>3sub>V>2-xsub>Mgx(PO>4sub>)>3sub>/C composites with different Mg2+ doping contents (x=0, 0.01, 0.03, 0.05, 0.07 and 0.1) were prepared by a facile sol-gel method. The doping effects on the crystal structure were investigated by XRD, XPS and EXAFS. The results show that low dose doping Mg2+ does not alter the structure of the material, and magnesium is successfully substituted for vanadium site. The Mg doped Na<sub>3sub>V>2-xsub>Mgx(PO>4sub>)>3sub>/C composites exhibit significant improvements on the electrochemistry performances in terms of the rate capability and cycle performance, especially for the Na<sub>3sub>V>1.95sub>Mg>0.05sub>(PO>4sub>)>3sub>/C. For example, when the current density increased from 1 C to 30 C, the specific capacity only decreased from 112.5 mAh g-1 to 94.2 mAh g-1 showing very good rate capability. Moreover, even cycling at a high rate of 20 C, an excellent capacity retention of 81% is maintained from the initial value of 106.4 mAh g-1 to 86.2 mAh g-1 at the 50th cycle. Enhanced rate capability and cycle performance can be attributed to the optimized particle size, structural stability and enhanced ionic and electronic conductivity induced by Mg doping.

  18. Influence of Electron Doping on Magnetic Order in CeRu<sub>2sub>Al>10sub>

    SciTech Connect (OSTI)

    Kobayashi, Riki; Kaneko, Koji; Saito, Kotaro; Mignot, Jean-Michel; André, Gilles; Robert, Julien; Wakimoto, Shuichi; Matsuda, Masaaki; Chi, Songxue; Haga, Yoshinori; Matsuda, Tatsuma D.; Yamamoto, Etsuji; Nishioka, Takashi; Matsumura, Masahiro; Tanida, Hiroshi; Sera, Masafumi

    2014-09-17

    The effect of electron doping by the substitution of Rh for Ru on unconventional magnetic order in CeRu<sub>2sub>Al>10sub> was investigated via neutron powder diffraction. In Ce(Ru<sub>1-xsub>Rhx)>2sub>Al>10sub> with x = 0.05, 0.12, and 0.2, reorientation of the ordered moment from the c- to the a-axis takes place in all samples, while the ordering vector q=(0 1 0) remains unchanged within this concentration range. The moment reorientation is accompanied by an enhancement in its size by a factor of ~2.4, from μ=0.43 μ<sub>B> at x=0 to μ =1.06, 1.04, and 1.02 μ<sub>B> for x=0.05, 0.12 and 0.2, respectively. The continuous decrease in N´eel temperature T<sub>0sub>(TN>), despite an abrupt increase in μ , underlines the strong anisotropy in the exchange interaction in CeRu<sub>2sub>Al>10sub>, and the fact that this anisotropy is easily suppressed by electron doping.

  19. Octonary resistance states in La<sub>0.7sub>Sr>0.3sub>MnO>3sub>/BaTiO>3sub>/La>0.7sub>Sr>0.3sub>MnO>3sub> multiferroic tunnel junctions

    SciTech Connect (OSTI)

    Yue -Wei Yin; Tao, Jing; Huang, Wei -Chuan; Liu, Yu -Kuai; Yang, Sheng -Wei; Dong, Si -Ning; Zhu, Yi -Mei; Li, Qi; Li, Xiao -Guang

    2015-10-06

    General drawbacks of current electronic/spintronic devices are high power consumption and low density storage. A multiferroic tunnel junction (MFTJ), employing a ferroelectric barrier layer sandwiched between two ferromagnetic layers, presents four resistance states in a single device and therefore provides an alternative way to achieve high density memories. Here, an MFTJ device with eight nonvolatile resistance states by further integrating the design of noncollinear magnetization alignments between the ferromagnetic layers is demonstrated. Through the angle-resolved tunneling magnetoresistance investigations on La<sub>0.7sub>Sr>0.3sub>MnO>3sub>/BaTiO>3sub>/La>0.7sub>Sr>0.3sub>MnO>3sub> junctions, it is found that, besides collinear parallel/antiparallel magnetic configurations, the MFTJ shows at least two other stable noncollinear (45° and 90°) magnetic configurations. As a result, combining the tunneling electroresistance effect caused by the ferroelectricity reversal of the BaTiO<sub>3sub> barrier, an octonary memory device is obtained, representing potential applications in high density nonvolatile storage in the future.

  20. Increased photocatalytic activity of TiO<sub>2sub> mesoporous microspheres from codoping with transition metals and nitrogen

    SciTech Connect (OSTI)

    Mathis, John E.; Lieffers, Justin J.; Mitra, Chandrima; Reboredo, Fernando A.; Bi, Z.; Bridges, Craig A.; Kidder, Michelle K.; Paranthaman, Mariappan Parans

    2015-11-06

    The composition of anatase TiO<sub>2sub> was modified by codoping using combinations of a transition metal and nitrogen in order to increase its photocatalytic activity and extend it performance in the visible region of the electromagnetic spectrum. The transition metals (Mn, Co, Ni, Cu) were added during the hydrothermal preparation of mesoporous TiO<sub>2sub> particles, and the nitrogen was introduced by post-annealing in flowing ammonia gas at high temperature. The samples were analyzed by SEM, XRD, BET, inductively-coupled plasma spectroscopy, and diffuse reflectance UV-vis spectroscopy. The photocatalytic activity was assessed by observing the change in methylene blue concentrations under both UV-vis and visible-only light irradiation. As a result, the photocatalytic activity of the (Mn,N), (Co,N), (Cu,N), and Ni,N) codoped TiO<sub>2sub> was significantly enhanced relative to (N) TiO<sub>2sub>.

  1. Characterization of collision cascade damage in Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2} by HRTEM

    SciTech Connect (OSTI)

    Weber, W.J.; Wang, L.M.

    1994-12-01

    Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2} thin crystals become amorphous under ion beam irradiation. The ion dose required for complete amorphization of the thin crystal (critical amorphization dose, D{sub c}) increased with the increasing irradiation temperature and decreased with ion mass at elevated temperatures. Samples irradiated with 1-1.5 MeV Ar{sup +}, Kr{sup +} and Xe{sup +} ions to doses much lower than Dc, in the temperature range from 20 to 498 K were used for a detailed HRTEM study to better understand the amorphization process. The residual collision cascade damage after irradiation appeared as manometer scale amorphous domains. The images of these domains are extremely sensitive to the sample thickness. Small domains of cascade size were only found at the very thin edge of the sample. In thicker regions, amorphous domains appear after higher doses as the result of cascade overlap in projection. At higher temperatures, the observed amorphous domains are smaller indicating thermal recovery at the amorphous/crystalline interface. The amorphous domains are also larger in size after irradiation with ions of higher mass at a fixed ion dose. These results are consistent with the Dc-temperature curves determined by in situ TEM with the HVEM-Tandem Facility at Argonne National Laboratory. The width of the amorphous rim along the edge of the specimen grew with increasing ion dose suggesting that amorphization also proceeds from the sample surface. Images of the collision cascade damage were compared to the cascade sizes calculated with the TRIM code. Some digitally acquired HRTEM images of the cascade damage were processed to reveal more detailed information.

  2. La??<sub>xSrx>CuO? superconductor nanowire devices

    SciTech Connect (OSTI)

    Litombe, N. E.; Bollinger, A. T.; Hoffman, J. E.; Bozovic, I.

    2014-07-02

    La??<sub>xSrx>CuO? nanowire devices have been fabricated and characterized using electrical transport measurements. Nanowires with widths down to 80 nm are patterned using high-resolution electron beam lithography. However, the narrowest nanowires show incomplete superconducting transitions with some residual resistance at T = 4 K. Here, we report on refinement of the fabrication process to achieve narrower nanowire devices with complete superconducting transitions, opening the path to the study of novel physics arising from dimension-limited superconductivity on the nanoscale.

  3. Influence of Ga-concentration on the electrical and magnetic properties of magnetoelectric CoGa<sub>xFe>2–xsub>O>4sub>/BaTiO>3sub> composite

    SciTech Connect (OSTI)

    Ni, Yan; Zhang, Zhen; Nlebedim, Cajetan I.; Jiles, David C.

    2015-03-20

    Multiferroic materials exhibit magnetoelectric (ME) coupling and promise new device applications including magnetic sensors, generators, and filters. An effective method for developing ME materials with enhanced ME effect is achieved by the coupling through the interfacial strain between piezoelectric and magnetostrictive materials. In this study, the electrical and magnetic properties of Ga doped magnetoelectric CoGa<sub>xFe>2–xsub>O>4sub>/BaTiO>3sub> composite are studied systematically. It is found that Ga doping improves the sensitivity of magnetoelastic response and stabilizes the magnetic phase of the composites. More importantly, Ga doping reduces the electrical conductivity of composite, as well as the dielectric loss. An enhancement of the electrostrain with doping Ga is also observed. Quantitative estimation indicates that magnetoelectric coupling is enhanced for Ga-doped CoGa<sub>xFe>2–xsub>O>4sub>/BaTiO>3sub> composites. As a result, the present work is beneficial to the practical application of composite CoFe<sub>2sub>O>4sub>/BaTiO>3sub>-based multiferroic materials.

  4. Microsoft Word - new_york.doc

    U.S. Energy Information Administration (EIA) Indexed Site

    Electricity Profiles 2010 1 Table 1. 2010 Summary Statistics Item Value U.S. Rank New York NERC Region(s) ......

  5. Next Update: November 2016 Geographic Area Capacity In-Service

    U.S. Energy Information Administration (EIA) Indexed Site

    Geographic Area Capacity In-Service Data Year NERC Region Type Operating (kV) Design (kV) Rating (MVa) Month/Year From Terminal To Terminal Length (Miles) Type Company Code Company Name Organizational Type Ownership (Percent) Project Name Level of Certainty Primary Driver 1 Primary Driver 2 2014 FRCC AC 200-299 115 460 1/2016 SUB 4 230.00 SUB 7 230.00 3.8 OH 18445 of Tallahassee M 100% 0.00 - SUB 7 230.00 Under Constructio Reliability 2014 FRCC AC 100-120 115 232 12/2016 Sub 14 115 Sub 7 115 6.0

  6. Abnormal thermal conductivity in tetragonal tungsten bronze Ba{sub 6−x}Sr{sub x}Nb{sub 10}O{sub 30}

    SciTech Connect (OSTI)

    Kolodiazhnyi, T. Sakurai, H.; Vasylkiv, O.; Borodianska, H.; Mozharivskyj, Y.

    2014-03-17

    Ba{sub 6−x}Sr{sub x}Nb{sub 10}O{sub 30} solid solution with 0 ≤ x ≤ 6 crystallizes in centrosymmetric tetragonal “tungsten bronze” structure (space group P4/mbm). We report on the x dependence of thermal conductivity of polycrystalline samples measured in the 2–400 K temperature interval. Substitution of Sr for Ba brings about a significant decrease in thermal conductivity at x ≥ 3 accompanied by development of a low-temperature (T ≈ 10–30 K) “plateau” region reminiscent of a glass-like compounds. We explain this behaviour based on a size-driven site occupancy and atomic displacement parameters associated with an alkaline earth atomic positions in the title compounds.

  7. Quantum-mechanical simulation of the IR reflectance spectrum of Mn{sub 3}Al{sub 2}Si{sub 3}O{sub 12} spessartine

    SciTech Connect (OSTI)

    Ferrari, A. M.; Demichelis, R.; Meyer, A.; Maschio, L.; Dovesi, R.; Pascale, F.

    2015-01-22

    The reflectance spectrum of one member of the garnet family, Mn{sub 3}Al{sub 2}Si{sub 3}O{sub 12} spessartine, was computed at the ab initio level with an all electron Gaussian type basis set and the B3LYP Hamiltonian. The static high frequency dielectric constant was obtained by applying the Coupled Perturbed Kohn Sham scheme as implemented in the CRYSTAL code; the Hessian matrix was evaluated numerically starting from the analytical gradients of the total energy with respect to the Cartesian coordinates of the atoms; the oscillator strengths were computed from well localized Wannier functions. An excellent agreement was obtained with the corresponding experimental spectrum, the exception being the very low frequency region.

  8. Quantum cascade laser investigations of CH{sub 4} and C{sub 2}H{sub 2} interconversion in hydrocarbon/H{sub 2} gas mixtures during microwave plasma enhanced chemical vapor deposition of diamond

    SciTech Connect (OSTI)

    Ma Jie; Cheesman, Andrew; Ashfold, Michael N. R.; Hay, Kenneth G.; Wright, Stephen; Langford, Nigel; Duxbury, Geoffrey; Mankelevich, Yuri A.

    2009-08-01

    CH{sub 4} and C{sub 2}H{sub 2} molecules (and their interconversion) in hydrocarbon/rare gas/H{sub 2} gas mixtures in a microwave reactor used for plasma enhanced diamond chemical vapor deposition (CVD) have been investigated by line-of-sight infrared absorption spectroscopy in the wavenumber range of 1276.5-1273.1 cm{sup -1} using a quantum cascade laser spectrometer. Parameters explored include process conditions [pressure, input power, source hydrocarbon, rare gas (Ar or Ne), input gas mixing ratio], height (z) above the substrate, and time (t) after addition of hydrocarbon to a pre-existing Ar/H{sub 2} plasma. The line integrated absorptions so obtained have been converted to species number densities by reference to the companion two-dimensional (r,z) modeling of the CVD reactor described in Mankelevich et al. [J. Appl. Phys. 104, 113304 (2008)]. The gas temperature distribution within the reactor ensures that the measured absorptions are dominated by CH{sub 4} and C{sub 2}H{sub 2} molecules in the cool periphery of the reactor. Nonetheless, the measurements prove to be of enormous value in testing, tensioning, and confirming the model predictions. Under standard process conditions, the study confirms that all hydrocarbon source gases investigated (methane, acetylene, ethane, propyne, propane, and butane) are converted into a mixture dominated by CH{sub 4} and C{sub 2}H{sub 2}. The interconversion between these two species is highly dependent on the local gas temperature and the H atom number density, and thus on position within the reactor. CH{sub 4}->C{sub 2}H{sub 2} conversion occurs most efficiently in an annular shell around the central plasma (characterized by 1400sub gas}<2200 K), while the reverse transformation C{sub 2}H{sub 2}->CH{sub 4} is favored in the more distant regions where T{sub gas}<1400 K. Analysis of the multistep interconversion mechanism reveals substantial net consumption of H atoms accompanying the CH{sub 4}->C{sub 2}H{sub 2} conversion, whereas the reverse C{sub 2}H{sub 2}->CH{sub 4} process only requires H atoms to drive the reactions; H atoms are not consumed by the overall conversion.

  9. Scaling of Dynamic Spin Correlations in BaCu<sub>2sub>(Si>0.5sub>Ge>0.5sub>)>2sub>O>7sub>

    SciTech Connect (OSTI)

    Zheludev, Andrey I; Masuda, T.; Dhalenne, G.; Revcolevschi, A.; Frost, C.; Perring, T. G.

    2007-01-01

    The magnetic dynamic structure factor of the one-dimensional S=1/2 chain system BaCu{sub 2}(Si{sub 0.5}Ge{sub 0.5}){sub 2}O{sub 7} is studied in a wide range of energy transfers and temperatures. Contrary to previous erroneous reports [T. Masuda et al., Phys. Rev. Lett. 93, 077206 (2004)], the scaling properties observed in the range 0.5-25 meV are found to be fully consistent with expectations for a Luttinger spin liquid. At higher energies, a breakdown of scaling laws is observed and attributed to lattice effects. The results are complementary to those found in literature for other S=1/2 chain compounds, such as KCuF{sub 3} and Cu benzoate.

  10. Low NO.sub.x multistage combustor

    DOE Patents [OSTI]

    Becker, Frederick E.; Breault, Ronald W.; Litka, Anthony F.; McClaine, Andrew W.; Shukla, Kailash

    2000-01-01

    A high efficiency, Vortex Inertial Staged Air (VIStA) combustor provides ultra-low NO.sub.X production of about 20 ppmvd or less with CO emissions of less than 50 ppmvd, both at 3% O.sub.2. Prompt NO.sub.X production is reduced by partially reforming the fuel in a first combustion stage to CO and H.sub.2. This is achieved in the first stage by operating with a fuel rich mixture, and by recirculating partially oxidized combustion products, with control over stoichiometry, recirculation rate and residence time. Thermal NO.sub.X production is reduced in the first stage by reducing the occurrence of high temperature combustion gas regions. This is achieved by providing the first stage burner with a thoroughly pre-mixed fuel/oxidant composition, and by recirculating part of the combustion products to further mix the gases and provide a more uniform temperature in the first stage. In a second stage combustor thermal NO.sub.X production is controlled by inducing a large flow of flue gas recirculation in the second stage combustion zone to minimize the ultimate temperature of the flame. One or both of the first and second stage burners can be cooled to further reduce the combustion temperature and to improve the recirculation efficiency. Both of these factors tend to reduce production of NO.sub.X.

  11. Observation of fast nonbolometric optical response of nongranular high T/sub c/ Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7-//sub x/ superconducting thin films

    SciTech Connect (OSTI)

    Frenkel, A.; Saifi, M.A.; Venkatesan, T.; Lin, C.; Wu, X.D.; Inam, A.

    1989-04-17

    We report fast optical response measurements in predominantly c-axis oriented crystalline Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7-//sub x/ superconducting thin films at the wavelength of 1.06 ..mu..m. We identify two distinct components contributing to the optical response: a nonbolometric (as fast as 1 ns) and a bolometric component (several ns). The bolometric component is stronger at temperatures in the vicinity of the transition region to the normal state. The nonbolometric component is dominant at temperatures below the transition region showing weak temperature dependence and a linear dependence on the bias current. This nonbolometric component may be evidence for nonequilibrium effects (e.g., breaking of Cooper pairs and generation of quasiparticles or other mechanisms). These results suggest that with proper optimization of device parameters (its geometry, critical current density, etc.) high-speed detectors with reasonable sensitivity covering a broad electromagnetic spectrum (visible and infrared) may be developed.

  12. Anomalous temperature dependence in valence band spectra: A resonant photoemission study of layered perovskite Sr{sub 2}CoO{sub 4}

    SciTech Connect (OSTI)

    Pandey, Pankaj K.; Choudhary, R. J. Phase, D. M.

    2014-05-05

    Valence band spectra (VBS) and its modification across Curie temperature (T{sub C}) of Sr{sub 2}CoO{sub 4} thin film are studied using resonant photoemission spectroscopy. It is found that VBS mainly consists of hybridized states of Co-3d t{sub 2g}e{sub g} and O-2p; however, Co-3d e{sub g} states show its prominence only in the ferromagnetic temperature regime. Below T{sub C}, spectral weight transfer takes place anomalously from high binding energy (B.E.) region to low B.E. region, signifying the enhanced intermediate or low spin state Co{sup 4+} ions. It is suggested that spin-lattice coupling and many-body effects in Sr{sub 2}CoO{sub 4} derived from the strong electron correlations lead to such temperature dependence of VBS.

  13. Eu<sub>3sub>Ir>2sub>In>15sub>: A mixed-valent and vacancy-filled variant of the Sc<sub>5sub>Co>4sub>Si>10sub> structure type with anomalous magnetic properties

    SciTech Connect (OSTI)

    Sarkar, Sumanta; Jana, Rajkumar; Siva, Ramesh; Banerjee, Swastika; Pati, Swapan K.; Balasubramanian, Mahalingam; Peter, Sebastian C.

    2015-10-27

    Here, a new compound, Eu<sub>3sub>Ir>2sub>In>15sub> has been synthesized using indium as an active metal flux. The compound crystallizes in tetragonal P4/mbm space group with lattice parameters, a = 14.8580(4) Å, b = 14.8580(4) Å, c = 4.3901(2) Å. It was further characterized by SEM-EDX studies. The temperature dependent magnetic susceptibility suggests that Eu in this compound is exclusively in divalent state. The effective magnetic moment (μ<sub>eff>) of this compound is 7.35 μ<sub>B>/Eu ion with paramagnetic Curie temperature (θ<sub>p>) of -28 K suggesting antiferromagnetic interaction. The mixed valent nature of Eu observed in magnetic measurements was confirmed by XANES measurements. The compound undergoes demagnetization at a low magnetic field (10 Oe), which is quite unusual for Eu based intermetallic compounds. Temperature dependent resistivity studies reveal that the compound is metallic in nature. A comparative study was made between Eu<sub>3sub>Ir>2sub>In>15sub> and hypothetical vacancy variant Eu<sub>5sub>Ir>4sub>In>10sub> which also crystallizes in the same crystal structure However our computational studies along with control experiments suggest that the latter is thermodynamically less feasible compared to the former and hence we proposed that it is highly unlikely that a RE<sub>5sub>T>4sub>X>10sub> would exist with X as a group 13 elements.

  14. The thermal conductivity of mixed fuel U<sub>xPu>1-xsub>O>2sub>: molecular dynamics simulations

    SciTech Connect (OSTI)

    Liu, Xiang-Yang; Cooper, Michael William Donald; Stanek, Christopher Richard; Andersson, Anders David Ragnar

    2015-10-16

    Mixed oxides (MOX), in the context of nuclear fuels, are a mixture of the oxides of heavy actinide elements such as uranium, plutonium and thorium. The interest in the UO<sub>2sub>-PuO>2sub> system arises from the fact that these oxides are used both in fast breeder reactors (FBRs) as well as in pressurized water reactors (PWRs). The thermal conductivity of UO<sub>2sub> fuel is an important material property that affects fuel performance since it is the key parameter determining the temperature distribution in the fuel, thus governing, e.g., dimensional changes due to thermal expansion, fission gas release rates, etc. For this reason it is important to understand the thermal conductivity of MOX fuel and how it differs from UO<sub>2sub>. Here, molecular dynamics (MD) simulations are carried out to determine quantitatively, the effect of mixing on the thermal conductivity of U<sub>xPu>1-xsub>O>2sub>, as a function of PuO<sub>2sub> concentrations, for a range of temperatures, 300 – 1500 K. The results will be used to develop enhanced continuum thermal conductivity models for MARMOT and BISON by INL. These models express the thermal conductivity as a function of microstructure state-variables, thus enabling thermal conductivity models with closer connection to the physical state of the fuel.

  15. Annealing influence on the magnetostructural transition in Gd<sub>5sub>Si>1.3sub>Ge>2.7sub> thin films

    SciTech Connect (OSTI)

    Pires, A. L.; Belo, J. H.; Gomes, I. T.; Hadimani, R. L.; Jiles, D. C.; Fernandes, L.; Tavares, P. B.; Araújo, J. P.; Lopes, A. M. L.; Pereira, A. M.

    2015-05-19

    Due to the emerging cooling possibilities at the micro and nanoscale, such as the fast heat exchange rate, the effort to synthesize and optimize the magnetocaloric materials at these scales is rapidly growing. Here, we report the effect of different thermal treatments on Gd<sub>5sub>Si>1.3sub>Ge>2.7sub> thin film in order to evaluate the correlation between the crystal structure, magnetic phase transition and magnetocaloric effect. For annealing temperatures higher than 500ºC, the samples showed a typical paramagnetic behavior. On the other hand, thermal treatments below 500ºC promoted the suppression of the magnetostructural transition at 190 K, while the magnetic transition around 249 K is not affected. This magnetostructural transition extinction was reflected in the magnetocaloric behavior and resulted in a drastic decrease in the entropy change peak value (of about 68%). An increase in T<sub>C> was reported, proving that at the nanoscale, heat treatments may be a useful tool to optimize the magnetocaloric properties in Gd<sub>5sub>(SixGe>1-xsub>)>4sub> thin films.

  16. Magnetic structure of the antiferromagnetic Kondo lattice compounds CeRhAl<sub>4sub>Si>2sub> and CeIrAl<sub>4sub>Si>2sub>

    SciTech Connect (OSTI)

    Ghimire, N. J.; Calder, S.; Janoschek, M.; Bauer, E. D.

    2015-06-01

    In this article, we have investigated the magnetic ground state of the antiferromagnetic Kondo-lattice compounds CeMAl<sub>4sub>Si>2sub>(M = Rh, Ir) using neutron powder diffraction. Although both of these compounds show two magnetic transitions T<sub>N1sub> and T<sub>N2sub> in the bulk properties measurements, evidence for magnetic long-range order was only found below the lower transition T<sub>N2sub>. Analysis of the diffraction profiles reveals a commensurate antiferromagnetic structure with a propagation vector k = (0, 0, 1/2). The magnetic moment in the ordered state of CeRhAl<sub>4sub>Si>2sub> and CeIrAl<sub>4sub>Si>2sub> were determined to be 1.14(2) and 1.41(3) <sub>?B>/Ce, respectively, and are parallel to the crystallographic c-axis in agreement with magnetic susceptibility measurements.

  17. Laser activation of ferromagnetism in hydrogenated Ga{sub 1-x}Mn{sub x}As

    SciTech Connect (OSTI)

    Farshchi, R.; Dubon, O. D.; Hwang, D. J.; Misra, N.; Grigoropoulos, C. P.; Ashby, P. D.

    2008-01-07

    We demonstrate the local depassivation of hydrogenated Ga{sub 1-x}Mn{sub x}As by pulsed-laser annealing. The controlled removal of Mn-H defect complexes, which form upon hydrogenation and render Mn acceptors inactive, is achieved by focused laser irradiation. As a result, regions of electrically and ferromagnetically active Ga{sub 1-x}Mn{sub x}As are formed within a nonactive, otherwise structurally identical film. The hydrogenated films subjected to blanket laser depassivation display a Curie temperature T{sub C} up to 60 K, or 60% of the T{sub C} of the as-grown films. These results demonstrate the direct laser writing of mesoscopic ferromagnetically active regions as a viable route for the realization of planar, nanoscale spintronic systems.

  18. Ammonia and methane dairy emissions in the San Joaquin Valley of California from individual feedlot to regional scale

    SciTech Connect (OSTI)

    Miller, David J.; Sun, Kang; Tao, Lei; Nowak, John B.; Liu, Zhen; Diskin, Glenn; Sasche, Glen; Beyersdorf, Andreas; Ferrare, Richard; Scarino, Amy Jo; Zondlo, Mark A.; Pan, Da

    2015-09-27

    Agricultural ammonia (NH<sub>3sub>) emissions are highly uncertain, with high spatiotemporal variability and a lack of widespread in situ measurements. Regional NH<sub>3sub> emission estimates using mass balance or emission ratio approaches are uncertain due to variable NH<sub>3sub> sources and sinks as well as unknown plume correlations with other dairy source tracers. We characterize the spatial distributions of NH<sub>3sub> and methane (CH<sub>4sub>) dairy plumes using in situ surface and airborne measurements in the Tulare dairy feedlot region of the San Joaquin Valley, California, during the NASA Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality 2013 field campaign. Surface NH<sub>3sub> and CH<sub>4sub> mixing ratios exhibit large variability with maxima localized downwind of individual dairy feedlots. The geometric mean NH<sub>3sub>:CH>4sub> enhancement ratio derived from surface measurements is 0.15 ± 0.03 ppmv ppmv–1. Individual dairy feedlots with spatially distinct NH<sub>3sub> and CH<sub>4sub> source pathways led to statistically significant correlations between NH<sub>3sub> and CH<sub>4sub> in 68% of the 69 downwind plumes sampled. At longer sampling distances, the NH<sub>3sub>:CH>4sub> enhancement ratio decreases 20–30%, suggesting the potential for NH<sub>3sub> deposition as a loss term for plumes within a few kilometers downwind of feedlots. Aircraft boundary layer transect measurements directly above surface mobile measurements in the dairy region show comparable gradients and geometric mean enhancement ratios within measurement uncertainties, even when including NH<sub>3sub> partitioning to submicron particles. Individual NH<sub>3sub> and CH<sub>4sub> plumes sampled at close proximity where losses are minimal are not necessarily correlated due to lack of mixing and distinct source pathways. As a result, our analyses have important implications for constraining NH<sub>3sub> sink and plume variability influences on regional NH<sub>3sub> emission estimates and for improving NH<sub>3sub> emission inventory spatial allocations.

  19. Pressure dependence of the monoclinic phase in (1x)Pb(Mg<sub>1/3sub>Nb>2/3sub>)O>3sub>-xPbTiO? solid solutions

    SciTech Connect (OSTI)

    Ahart, Muhtar; Sinogeikin, Stanislav; Shebanova, Olga; Ikuta, Daijo; Ye, Zuo-Guang; Mao, Ho-kwang; Cohen, R. E.; Hemley, Russell J.

    2012-12-26

    We combine high-pressure x-ray diffraction, high-pressure Raman scattering, and optical microscopy to investigate a series of (1x)Pb(Mg<sub>1/3sub>Nb>2/3sub>)O>3sub>-xPbTiO? (PMN-xPT) solid solutions (x=0.2, 0.3, 0.33, 0.35, 0.37, 0.4) in diamond anvil cells up to 20 GPa at 300 K. The Raman spectra show a peak centered at 380 cm? starting above 6 GPa for all samples, in agreement with previous observations. X-ray diffraction measurements are consistent with this spectral change indicating a structural phase transition; we find that the triplet at the pseudocubic (220) Bragg peak merges into a doublet above 6 GPa. Our results indicate that the morphotropic phase boundary region (x=0.330.37) with the presence of monoclinic symmetry persists up to 7 GPa. The pressure dependence of ferroelectric domains in PMN-0.32PT single crystals was observed using a polarizing optical microscope. The domain wall density decreases with pressure and the domains disappear at a modest pressure of 3 GPa. We propose a pressure-composition phase diagram for PMN-xPT solid solutions.

  20. Structural characterization of the CeO{sub 2}/Gd{sub 2}O{sub 3} mixed system by synchrotron X-ray diffraction

    SciTech Connect (OSTI)

    Artini, Cristina; Costa, Giorgio A.; Pani, Marcella; Lausi, Andrea; Plaisier, Jasper

    2012-06-15

    The structural determination of the CeO{sub 2}/Gd{sub 2}O{sub 3} mixed system is a non-trivial problem because of the close resemblance between the ionic sizes of Ce{sup 4+} and Gd{sup 3+} and between the crystal structures of CeO{sub 2} and Gd{sub 2}O{sub 3}. (Ce{sub 1-x}Gd{sub x})O{sub 2-x/2} powder samples with x ranging between 0 and 1 have been synthesized by coprecipitation of mixed oxalates and subsequent thermal decomposition in air at 1200 Degree-Sign C followed by slow cooling. Synchrotron powder X-ray diffraction data were collected and refined by the Rietveld method. Lattice parameters do not follow Vegard's law and no peak splitting has been observed for any composition, meaning that no biphasic regions exist over the whole compositional range. The same hybrid structural model - a proper mixture of the structures of the two pure oxides - was used for the refinements, allowing to account for the data observed. - graphical abstract: Substituting Ce{sup 4+} by Gd{sup 3+}, a gradual transition from the F structure (typical of CeO{sub 2}) to the C structure (typical of Gd{sub 2}O{sub 3}) takes place. The lattice parameters do not follow Vegard's law. Highlights: Black-Right-Pointing-Pointer A structural study of Ce-Gd mixed oxides has been performed. Black-Right-Pointing-Pointer In (Ce{sub 1-x}Gd{sub x})O{sub 2-x/2} a solid solution forms for 0{<=}x{<=}0.3. Black-Right-Pointing-Pointer For x>0.3 a gradual transition from the C to the F structure is observed. Black-Right-Pointing-Pointer Lattice parameters do not follow Vegard's law.

  1. The CO<sub>2sub> permeability and mixed gas CO<sub>2sub>/H>2sub> selectivity of membranes composed of CO<sub>2sub>-philic polymers

    SciTech Connect (OSTI)

    Barillas, Mary Katharine; Enick, Robert M.; O’Brien, Michael; Perry, Robert; Luebke, David R.; Morreale, Bryan D.

    2011-04-01

    The objective of this work was to design polymeric membranes that have very high CO<sub>2sub> permeability and high mixed gas selectivity toward CO<sub>2sub> rather than hydrogen. Therefore the membranes were based on "CO<sub>2sub>-philic" polymers that exhibit thermodynamically favorable Lewis acid:Lewis base and hydrogen bonding interactions with CO<sub>2sub>. CO<sub>2sub>-philic polymers that are solid at ambient temperature include polyfluoroacrylate (PFA); polyvinyl acetate (PVAc); and amorphous polylactic acid (PLA). Literature CO<sub>2sub> permeability values for PVAc and PLA are disappointingly low. The cast PFA membranes from this study had low permeabilities (45 barrers at 25º C) and very low CO<sub>2sub>/H>2sub> selectivity of 1.4. CO<sub>2sub>-philic polymers that are liquid at ambient conditions include polyethylene glycol (PEG), polypropylene glycol (PPG), polybutylene glycol with a linear -((CH<sub>2sub>)>4sub>O)-repeat unit (i.e., polytetramethylene ether glycol (PTMEG)), polybutylene glycol (PBG) with a branched repeat unit, perfluoropolyether (PFPE), poly(dimethyl siloxane) (PDMS), and polyacetoxy oxetane (PAO). A small compound, glycerol triacetate (GTA) was also considered because it is similar in chemical structure to a trimer of PVAc. These liquids were tested as supported liquid membranes (SLM) and also (with the exception of PAD and GTA) as rubbery, crosslinked materials. Mixed gas permeability was measured using equimolar mixtures of CO<sub>2sub> and H<sub>2sub> feed streams at one atmosphere total pressure in steady-state flux experiments over the 298-423 K temperature range. The most promising SLMs were those composed of PEG, PTMEG, GTA, and PDMS. For example, at 37º C the PEG-, PTMEG-, GTA- and PDMS-based SLMs exhibited CO<sub>2sub>/H>2sub> selectivity values of ~11, 9, 9, and 3.5, respectively, and CO<sub>2sub> permeability values of ~800, 900, 1900, and 2000 barrers, respectively. Crosslinked versions of the PEG, PTMEG and PDMS membranes at 37º C exhibited selectivity values of ~5, 6, and 3.5, respectively, and CO<sub>2sub> permeability values of ~50, 300, and 3000 barrers, respectively.

  2. Magnetic hardening of Ce<sub>1+xsub>Fe>11ysub>Coy>Ti with ThMn<sub>12sub> structure by melt spinning

    SciTech Connect (OSTI)

    Zhou, Chen; Sun, Kewei; Pinkerton, Frederick E.; Kramer, M. J.

    2015-04-15

    A recent study on the intrinsic magnetic properties of CeFe<sub>11ysub>Coy>Ti has revealed that substituting one Co for Fe retains the favorable magnetocrystalline anisotropy H<sub>a> found in the ternary Fe end member, while enhancing the Curie temperature T<sub>c> and saturation magnetization 4?M<sub>s>. These findings warrant further optimization around Co substitution y = 1 to try to exploit the hard magnetic properties of these Ce-based magnets. Both Ce and Co concentrations in Ce<sub>1+xsub>Fe>11ysub>Coy>Ti have been optimized in the range of x = 0 0.2 and y = 0 1.5. It was found that Co substitution effectively enhances all hard magnetic properties, although the values are still lower than those predicted from the intrinsic magnetic properties. Specifically, T<sub>c> increases from 210 C to 285 350 C; 4?M<sub>19sub> (magnetization at 19 kOe) from 8.9 kG to 10.5 11.5 kG, remanence Br from 3.1 kG to 4.1 4.5 kG, and most importantly, H<sub>ci> from 1.1 kOe to 1.5 kOe. As a result, the room temperature energy product (BH)<sub>max> has been increased by over 100% from 0.7 MGOe in Ce<sub>1.1sub>Fe>11sub>Ti to 1.5 MGOe in Ce<sub>1.05sub>Fe>9.75sub>Co>1.25sub>Ti. Microscopy analysis indicates that the addition of Co refines the grain size and promotes chemical homogeneity at the microscopic scale. As a result, the beneficial effect of Co on the microstructure contributes to the improved hard magnetic properties.

  3. Structure determination of {alpha}-La{sub 6}W{sub 2}O{sub 15}

    SciTech Connect (OSTI)

    Chambrier, M-H.; Ibberson, R.M.; Goutenoire, F.

    2010-06-15

    The structure of the high temperature alpha form of La{sub 6}W{sub 2}O{sub 15} has been determined ab-initio from high temperature laboratory X-ray and neutron time-of-flight data. This tungstate crystallizes in the non-centrosymmetric orthorhombic space group (No. 20) C222{sub 1}, with Z=2, a=12.6250(2) A, b=9.1875(1) A, c=5.9688(1) A. The structure comprises [O{sub 2}La{sub 3}] infinite ribbons and is better described by the structural formula [O{sub 2}La{sub 3}]{sub 2}[WO{sub 5.5}]{sub 2}. Using this description we can understand the strong structural similarity of the present compound with compounds of the general composition BiM{sub 2}AO{sub 6} (M=Cu, Mg, Zn, Mn, Cd, Ca, Pb; A=P, As, V) described as [O{sub 2}M{sub 2}Bi][AO{sub 4}]. The [WO{sub 5.5}] entity implies oxygen disorder in the material. - Graphical abstract: Projection of the polyhedra around the tungsten atom. Atoms labelled in grey are occupied at 50%. Short oxygen-oxygen distances are marked. The polyhedra represents WO{sub 5.5} that is related to the structural unit W{sub 2}O{sub 11} unit. Alpha-La{sub 6}W{sub 2}O{sub 15} could be described as [O{sub 2}La{sub 3}]{sub 2}[WO{sub 5.5}]{sub 2}.

  4. Ferromagnetic superexchange in insulating Cr<sub>2sub>MoO>6sub> by controlling orbital hybridization

    SciTech Connect (OSTI)

    Zhu, M.; Do, D.; Dela Cruz, Clarina R.; Dun, Zhiling; Cheng, J. -G.; Goto, H.; Uwatoko, Yoshiya; Zou, T.; Zhou, Haidon D.; Mahanti, Subhendra D.; Ke, Xianglin

    2015-09-11

    We report the magnetic and electronic structures of the newly synthesized inverse-trirutile compound Cr<sub>2sub>MoO>6sub>. Despite the same crystal symmetry and similar bond-lengths and bond-angles to Cr<sub>2sub>TeO>6sub>, Cr<sub>2sub>MoO>6sub> possesses a magnetic structure of the Cr<sub>2sub>MoO>6sub> type, different from that seen in Cr<sub>2sub>TeO>6sub>. Ab-initio electronic structure calculations show that the sign and strength of the Cr-O-Cr exchange coupling is strongly influenced by the hybridization between Mo 4d and O 2p orbitals. This result further substantiates our recently proposed mechanism for tuning the exchange interaction between two magnetic atoms by modifying the electronic states of the non-magnetic atoms in the exchange path through orbital hybridization. This approach is fundamentally different from the conventional methods of controlling the exchange interaction by either carrier injection or through structural distortions.

  5. Measurement of the neutron F<sub>2sub> structure function via spectator tagging with CLAS

    SciTech Connect (OSTI)

    Baillie, N.; Tkachenko, S.; Zhang, J.; Bosted, P.; Bltmann, S.; Christy, M. E.; Fenker, H.; Griffioen, K. A.; Keppel, C. E.; Kuhn, S. E.; Melnitchouk, W.; Tvaskis, V.; Adhikari, K. P.; Adikaram, D.; Aghasyan, M.; Amaryan, M. J.; Anghinolfi, M.; Arrington, J.; Avakian, H.; Baghdasaryan, H.; Battaglieri, M.; Biselli, A. S.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Cole, P. L.; Contalbrigo, M.; Crede, V.; DAngelo, A.; Daniel, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Dey, B.; Djalali, C.; Dodge, G.; Domingo, J.; Doughty, D.; Dupre, R.; Dutta, D.; Ent, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fradi, A.; Gabrielyan, M. Y.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Graham, L.; Guegan, B.; Guidal, M.; Guler, N.; Guo, L.; Hafidi, K.; Heddle, D.; Hicks, K.; Holtrop, M.; Hungerford, E.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ispiryan, M.; Isupov, E. L.; Jawalkar, S. S.; Jo, H. S.; Kalantarians, N.; Khandaker, M.; Khetarpal, P.; Kim, A.; Kim, W.; King, P. M.; Klein, A.; Klein, F. J.; Klimenko, A.; Kubarovsky, V.; Kuleshov, S. V.; Kvaltine, N. D.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Mao, Y.; Markov, N.; McKinnon, B.; Mineeva, T.; Morrison, B.; Moutarde, H.; Munevar, E.; Nadel-Turonski, P.; Ni, A.; Niccolai, S.; Niculescu, I.; Niculescu, G.; Osipenko, M.; Ostrovidov, A. I.; Pappalardo, L.; Park, K.; Park, S.; Pasyuk, E.; Anefalos Pereira, S.; Pisano, S.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Ricco, G.; Rimal, D.; Ripani, M.; Rosner, G.; Rossi, P.; Sabati, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Sober, D. I.; Sokhan, D.; Stepanyan, S.; Stepanyan, S. S.; Stoler, P.; Strauch, S.; Taiuti, M.; Tang, W.; Ungaro, M.; Vineyard, M. F.; Voutier, E.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Wood, M. H.; Zana, L.; Zhao, B.

    2012-04-01

    We report on the first measurement of the F<sub>2sub> structure function of the neutron from semi-inclusive scattering of electrons from deuterium, with low-momentum protons detected in the backward hemisphere. Restricting the momentum of the spectator protons to ?< 100 MeV and their angles to ?> 100 degrees relative to the momentum transfer allows an interpretation of the process in terms of scattering from nearly on-shell neutrons. The F<sub>2sub>n data collected cover the nucleon resonance and deep-inelastic regions over a wide range of x for 0.65 < Q2 < 4.52 GeV2, with uncertainties from nuclear corrections estimated to be less than a few percent. These measurements provide the first determination of the neutron to proton structure function ratio F<sub>2sub>n/F>2sub>p at 0.2 ?< x ?< 0.8, essentially free of nuclear corrections.

  6. Colossal thermoelectric power in charge ordered lanthanum calcium manganites (La{sub 0.5}Ca{sub 0.5}MnO{sub 3})

    SciTech Connect (OSTI)

    Joy, Lija K.; Anantharaman, M. R.; Shanmukharao Samatham, S.; Ganesan, V.; Thomas, Senoy; Al-Harthi, Salim; Liebig, A.; Albrecht, M.

    2014-12-07

    Lanthanum calcium manganites (La{sub 0.5}Ca{sub 0.5}MnO{sub 3}) with a composition close to charge ordering, synthesized by high energy ball milling, was found to exhibit colossal thermoelectric power. Thermoelectric power (TEP) data was systematically analyzed by dividing the entire temperature range (5?K300?K) into three different regimes to explore different scattering mechanisms involved. Mandal's model has been applied to explain TEP data in the region below the Curie temperature (T{sub C}). It has been found that the variation of thermoelectric power with temperature is pronounced when the system enters the charge ordered region at T?region corresponding to a maximum value of thermoelectric power. Phonon drag contribution instead of spin-glass contribution is taken into account to explain TEP in the region 120?K?sub C}. Mott's polaronic contribution of charge carriers are considered to interpret TEP in the high temperature region (T?>?T{sub C}). The optimal Mn{sup 4+}-Mn{sup 3+} concentration in charge ordered La{sub 0.5}Ca{sub 0.5}MnO{sub 3} was examined by X-ray Photoelectron Spectroscopy analysis which confirms the charge ordered nature of this compound.

  7. Molecular beam epitaxial growth and characterization of Bi{sub 2}Se{sub 3}/II-VI semiconductor heterostructures

    SciTech Connect (OSTI)

    Chen, Zhiyi Zhao, Lukas; Krusin-Elbaum, Lia; Garcia, Thor Axtmann; Tamargo, Maria C.; Hernandez-Mainet, Luis C.; Deng, Haiming

    2014-12-15

    Surfaces of three-dimensional topological insulators (TIs) have been proposed to host quantum phases at the interfaces with other types of materials, provided that the topological properties of interfacial regions remain unperturbed. Here, we report on the molecular beam epitaxy growth of II-VI semiconductorTI heterostructures using c-plane sapphire substrates. Our studies demonstrate that Zn{sub 0.49}Cd{sub 0.51}Se and Zn{sub 0.23}Cd{sub 0.25}Mg{sub 0.52}Se layers have improved quality relative to ZnSe. The structures exhibit a large relative upward shift of the TI bulk quantum levels when the TI layers are very thin (?6nm), consistent with quantum confinement imposed by the wide bandgap II-VI layers. Our transport measurements show that the characteristic topological signatures of the Bi{sub 2}Se{sub 3} layers are preserved.

  8. Magnetic field, frequency and temperature dependence of complex conductance of ultrathin La<sub>1.65sub>Sr>0.45sub>CuO>4sub>/La>2sub>CuO>4sub> films and the organic superconductors κ-(BEDT-TTF)<sub>2sub>Cu[N(CN)>2sub>]Br

    SciTech Connect (OSTI)

    V. A. Gasparov; Bozovic, I.; He, Xi; Dubuis, G.; Pavuna, D.; Kushch, N. D.; Yagubskii, E. B.; Schlueter, J. A.

    2015-09-01

    In this study, we used atomic-layer molecular beam epitaxy (ALL-MBE) to synthesize bilayer films of a cuprate metal (La<sub>1.65sub>Sr>0.45sub>CuO>4sub>) and a cuprate insulator (La<sub>2sub>CuO>4sub>), in which interface superconductivity occurs in a layer that is just one-half unit cell thick. We have studied the magnetic field and temperature dependence of the complex sheet conductance, σ(ω), of these films, and compared them to κκ-(BEDT-TTF)<sub>2sub>Cu[N(CN)>2sub>]Br single crystals. The magnetic field H was applied both parallel and perpendicular to the 2D conducting layers. Experiments have been carried out at frequencies between 23 kHz and 50 MHz using either two-coil mutual inductance technique, or the LC resonators with spiral or rectangular coils. The real and the imaginary parts of the mutual-inductance M(T,ω) between the coil and the sample were measured and converted to complex conductivity. For H perpendicular to the conducting layers, we observed almost identical behavior in both films and κ-Br single crystals: (i) the transition onset in the inductive response, L<sub>k>–1(T) occurs at a temperature lower by 2 K than in Re σ(T), (ii) this shift is almost constant with magnetic field up to 8 T; (iii) the vortex diffusion constant D(T) is exponential due to pinning of vortex cores. These results can be described by the extended dynamic theory of the Berezinski–Kosterlitz–Thouless (BKT) transition and dynamics of bound vortex–antivortex pairs with short separation lengths.

  9. Synthesis and Luminescence Characteristics of Cr3+ doped Y<sub>3sub>Al>5sub>O>12sub> Phosphors

    SciTech Connect (OSTI)

    Smith, Brenda A.; Dabestani, Reza T.; Lewis, Linda A.; Thompson, Cyril V.; Collins, Case T.; Aytug, Tolga

    2015-10-01

    Luminescence performance of yttrium aluminum garnet (Y<sub>3sub>Al>5sub>O>12sub>) phosphors as a function of Cr3+ concentration has been investigated via two different wet-chemical synthesis techniques, direct- (DP) and hydrothermal-precipitation (HP). Using either of these methods, the red-emitting phosphor [Y<sub>3sub>Al>5-xsub>CrxO>12sub> (YAG: Cr3+)] showed similar photoluminescence (PL) intensities once the dopant concentration was optimized. Specifically, the YAG: Cr3+ PL emission intensity reached a maximum at Cr3+ concentrations of x = 0.02 (0.4 at.%) and x = 0.13 (2.6 at.%) for DP and HP processed samples, respectively. The results indicated the strong influence of the processing method on the optimized YAG: Cr3+ performance, where a more effective energy transfer rate between a pair of Cr3+ activators at low concentration levels was observed by using the DP synthesis technique. Development of a highly efficient phosphor, using a facile synthesis approach, could significantly benefit consumer and industrial applications by improving the operational efficiency of a wide range of practical devices.

  10. A novel magnetically separable TiO{sub 2}/CoFe{sub 2}O{sub 4} nanofiber with high photocatalytic activity under UV-vis light

    SciTech Connect (OSTI)

    Li, Cong-Ju; Wang, Jiao-Na; Wang, Bin; Gong, Jian Ru; Lin, Zhang

    2012-02-15

    Graphical abstract: A novel magnetically separable composite photocatalyst TiO{sub 2}/CoFe{sub 2}O{sub 4} nanofiber was prepared by sol-gel method and electrospinning technique, which can be reclaimed with a magnet, and the decolorizing efficiency of MB solution reached 95.87%. Highlights: Black-Right-Pointing-Pointer The composite TiO{sub 2}/CoFe{sub 2}O{sub 4} nanofibers with diameter of 110 {+-} 28 nm have been successfully synthesized by the combination of sol-gel method and electrospinning technique. Black-Right-Pointing-Pointer The presence of Co{sup 2+} or/and Fe{sup 3+} ions may occupy some of the lattice sites of TiO{sub 2} to form an iron-titanium solid solution and narrow the band gap, which broadens the response region of visible light. Black-Right-Pointing-Pointer The resultant nanofibers not only have high decomposition efficiency with methylene blue (MB) under the UV irradiation, which is close to that of Degussa P25, but also can be separated with a magnet and avoid the secondary pollution of the treated water. -- Abstract: A novel magnetically separable heterogeneous photocatalyst TiO{sub 2}/CoFe{sub 2}O{sub 4} nanofiber was prepared by sol-gel method and electrospinning technology, followed by heat treatment at 550 Degree-Sign C for 2 h. The phase structure, morphology and magnetic property of the composite nanofibers were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscope and vibrating sample magnetometer analysis. The photocatalytic studies of TiO{sub 2}/CoFe{sub 2}O{sub 4} fibers suggested that the presence of CoFe{sub 2}O{sub 4} not only enhanced the absorbance of UV light, but also broadened the response region to visible light. The decolorizing efficiency of methylene blue (MB) solution reaches 95.87% over TiO{sub 2}/CoFe{sub 2}O{sub 4} nanofibers under 300 W Hg lamp after 5 h, which is close to that of Degussa P25. Furthermore, these fibers can be collected with a magnet for reuse and effectively avoid the secondary pollution of the treated water.

  11. Average and local crystal structures of (Ga<sub>1–xsub>Znx)(N>1–xsub>Ox>) solid solution nanoparticles

    SciTech Connect (OSTI)

    Feygenson, Mikhail; Neuefeind, Joerg C.; Tyson, Trevor A.; Schieber, Natalie; Han, Wei -Qiang

    2015-11-06

    We report the comprehensive study of the crystal structure of (Ga<sub>1–xsub>Znx)(N>1–xsub>Ox>) solid solution nanoparticles by means of neutron and synchrotron x-ray scattering. In our study we used four different types of (Ga<sub>1–xsub>Znx)(N>1–xsub>Ox>) nanoparticles, with diameters of 10–27 nm and x = 0.075–0.51, which show the narrow energy-band gaps from 2.21 to 2.61 eV. The Rietveld analysis of the neutron diffraction data revealed that the average crystal structure is the hexagonal wurtzite (space group P6<sub>3sub>mc), in agreement with previous reports on similar bulk materials. The pair-distribution function (PDF) analysis of the same data found that the local structure is more disordered than the average one. It is best described by the model with a lower symmetry space group P1, where atoms are quasirandomly distorted from their nominal positions in the hexagonal wurtzite lattice.

  12. Giant Magneto-Resistance in Epitaxial (La<sub>0.7sub>Sr>0.3sub>MnO>3sub>)>0.5sub>: (ZnO)<sub>0.5sub> Nanocomposites

    SciTech Connect (OSTI)

    Pan, Wei; Jiang, Y. X.; Ihlefeld, Jon; Lu, Ping; Lee, Stephen R.

    2015-12-01

    A great deal of research has been carried out in oxide material systems. Among them, ZnO and La<sub>0.7sub>Sr>0.3sub>MnO>3sub> (LSMO) are of particular interest due to their superb optical properties and colossal magneto-resistive effect. Here, we report our recent results of magneto-transport studies in self-assembled, epitaxial (ZnO)0.5:(La<sub>0.7sub>Sr>0.3sub>MnO>3sub>)>0.5sub> nanocomposite films.

  13. The effect of Cu content on the structure of Ni{sub 1-x}Cu{sub x}Fe{sub 2}O{sub 4} spinels

    SciTech Connect (OSTI)

    Tan, Xiaoyan; The Institute of Applied Chemistry, Central South University of Forestry and Technology, Changsha, Hunan 412006 ; Li, Guiying; Zhao, Ying; Hu, Changwei

    2009-12-15

    A series of Ni{sub 1-x}Cu{sub x}Fe{sub 2}O{sub 4} (0 {<=} x {<=} 0.5) spinels were synthesized employing sol-gel combustion method at 400 {sup o}C. The decomposition process was monitored by thermal analysis, and the synthesized nanocrystallites were characterized by X-ray diffraction, transmission electron microscopy, infra-red and X-ray photoelectron spectroscopy. The decomposition process and ferritization occur simultaneously over the temperature range from 280 {sup o}C to 350 {sup o}C. TEM indicates the increase of lattice parameter and particle size with the increase of copper content in accordance with the XRD analysis. Cu{sup 2+} can enter the cubic spinel phase and occupy preferentially the B-sites within x = 0.3, and redundant copper forms CuO phase separately. A broadening of the O 1s region increases with the increment of copper content compared to pure NiFe{sub 2}O{sub 4}, showing different surface oxygen species from the spinel and CuO. Cu{sup 2+} substitution favors the occupancy of A-sites by Fe{sup 3+}.

  14. Magnetic phase transitions and entropy change in layered NdMn{sub 1.7}Cr{sub 0.3}Si{sub 2}

    SciTech Connect (OSTI)

    Md Din, M. F. Dou, S. X.; Wang, J. L.; Campbell, S. J.; Studer, A. J.; Avdeev, M.; Kennedy, S. J.; Gu, Q. F.; Zeng, R.

    2014-01-27

    A giant magnetocaloric effect has been observed around the Curie temperature, T{sub C} ∼ 42 K, in NdMn{sub 1.7}Cr{sub 0.3}Si{sub 2} with no discernible thermal and magnetic hysteresis losses. Below 400 K, three magnetic phase transitions take place around 380 K, 320 K and 42 K. Detailed high resolution synchrotron and neutron powder diffraction (10–400 K) confirmed the magnetic transitions and phases as follows: T{sub N}{sup intra} ∼ 380 K denotes the transition from paramagnetism to intralayer antiferromagnetism (AFl), T{sub N}{sup inter} ∼ 320 K represents the transition from the AFl structure to the canted antiferromagnetic spin structure (AFmc), while T{sub C} ∼ 42 K denotes the first order magnetic transition from AFmc to canted ferromagnetism (Fmc + F(Nd)) due to ordering of the Mn and Nd sub-lattices. The maximum values of the magnetic entropy change and the adiabatic temperature change, around T{sub C} for a field change of 5 T are evaluated to be −ΔS{sub M}{sup max} ∼ 15.9 J kg{sup −1} K{sup −1} and ΔT{sub ad}{sup max} ∼ 5 K, respectively. The first order magnetic transition associated with the low levels of hysteresis losses (thermal <∼0.8 K; magnetic field <∼0.1 T) in NdMn{sub 1.7}Cr{sub 0.3}Si{sub 2} offers potential as a candidate for magnetic refrigerator applications in the temperature region below 45 K.

  15. Spin Hall magnetoresistance in CoFe<sub>2sub>O>4sub>/Pt films

    SciTech Connect (OSTI)

    Wu, Hao; Qintong, Zhang; Caihua, Wan; Ali, Syed Shahbaz; Yuan, Zhonghui; You, Lu; Wang, Junling; Choi, Yongseong; Han, Xiufeng

    2015-05-13

    Pulse laser deposition and magnetron sputtering techniques have been employed to prepare MgO(001)//CoFe<sub>2sub>O>4sub>/Pt samples. Cross section transmission electron microscope results prove that the CoFe<sub>2sub>O>4sub> film epitaxially grew along (001) direction. X-ray magnetic circular dichroism results show that magnetic proximity effect in this sample is negligible. Magnetoresistance (MR) properties confirm that spin Hall MR (SMR) dominates in this system. Spin Hall effect-induced anomalous Hall voltage was also observed in this sample. Lastly, these results not only demonstrate the universality of SMR effect but also demonstrate the utility in spintronics of CoFe<sub>2sub>O>4sub> as a new type of magnetic insulator.

  16. Investigation of room temperature ferromagnetic nanoparticles of Gd<sub>5sub>Si>4sub>

    SciTech Connect (OSTI)

    Hadimani, R. L.; Gupta, S.; Harstad, S. M.; Pecharsky, V. K.; Jiles, D. C.

    2015-07-06

    Gd<sub>5sub>(SixGe>1-xsub>)>4sub> compounds undergo first-order phase transitions close to room temperature when x ~ = 0.5, which are accompanied by extreme changes of properties. We report the fabrication of the nanoparticles of one of the parent compounds-Gd<sub>5sub>Si>4sub>-using high-energy ball milling. Crystal structure, microstructure, and magnetic properties have been investigated. Particles agglomerate at long milling times, and the particles that are milled >20 min lose crystallinity and no longer undergo magnetic phase transition close to 340 K, which is present in a bulk material. The samples milled for >20 min exhibit a slightly increased coercivity. As a result, magnetization at a high temperature of 275K decreases with the increase in the milling time.

  17. Selective interlayer ferromagnetic coupling between the Cu spins in YBa<sub>2sub>Cu>3sub>O>7–xsub> grown on top of La<sub>0.7sub>Ca>0.3sub>MnO>3sub>

    SciTech Connect (OSTI)

    Huang, S. W.; Wray, L. Andrew; Jeng, Horng -Tay; Tra, V. T.; Lee, J. M.; Langner, M. C.; Chen, J. M.; Roy, S.; Chu, Y. H.; Schoenlein, R. W.; Chuang, Y. -D.; Lin, J. -Y.

    2015-11-17

    Studies to date on ferromagnet/d-wave superconductor heterostructures focus mainly on the effects at or near the interfaces while the response of bulk properties to heterostructuring is overlooked. Here we use resonant soft x-ray scattering spectroscopy to reveal a novel c-axis ferromagnetic coupling between the in-plane Cu spins in YBa<sub>2sub>Cu>3sub>O>7–xsub> (YBCO) superconductor when it is grown on top of ferromagnetic La<sub>0.7sub>Ca>0.3sub>MnO>3sub> (LCMO) manganite layer. This coupling, present in both normal and superconducting states of YBCO, is sensitive to the interfacial termination such that it is only observed in bilayers with MnO<sub>2sub> but not with La<sub>0.7sub>Ca>0.3sub>O interfacial termination. Thus, such contrasting behaviors, we propose, are due to distinct energetic of CuO chain and CuO<sub>2sub> plane at the La<sub>0.7sub>Ca>0.3sub>O and MnO<sub>2sub> terminated interfaces respectively, therefore influencing the transfer of spin-polarized electrons from manganite to cuprate differently. Our findings suggest that the superconducting/ferromagnetic bilayers with proper interfacial engineering can be good candidates for searching the theorized Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) state in cuprates and studying the competing quantum orders in highly correlated electron systems.

  18. Fermi surface measurements in YBa sub 2 Cu sub 3 O sub 7-x and La sub 1. 874 Sr sub. 126 CuO sub 4

    SciTech Connect (OSTI)

    Howell, R.H.; Sterne, P.A.; Solal, F.; Fluss, M.J. ); Haghighi, H.; Kaiser, J.H.; Rayner, S.L.; West, R.N. ); Liu, J.Z; Shelton, R. ); Kojima, H. ); Kitazawa, K. )

    1991-06-25

    We report new, ultra high precision measurements of the electron-positron momentum spectra of YBa{sub 2}Cu{sub 3}O{sub 7-x} and La{sub 1.874}Sr{sub 126}CuO{sub 4}. The YBCO experiments were performed on twin free, single crystals and show discontinuities with the symmetry of the Fermi surface of the CuO chain bands. Conduction band and underlying features in LSCO share the same symmetry and can only be separated with the aid of LDA calculations. 5 refs., 3 figs.

  19. Study of microstructure, dielectric and ferromagnetic properties of the (1-x)Ba{sub 0.95}Sr{sub 0.05}TiO{sub 3}-(x)CoFe{sub 1.8}Mn{sub 0.2}O{sub 4} multiferroic composites

    SciTech Connect (OSTI)

    Sharma, Richa; Tandon, R. P.

    2015-05-15

    In the present work, (1-x)Ba{sub 0.95}Sr{sub 0.05}TiO{sub 3}-(x)CoFe{sub 1.8}Mn{sub 0.2}O{sub 4} composites are prepared by standard solid state reaction method. The X-ray diffraction measurement of the composites shows that both the phases coexist in the composite, individually. The morphology of the composites were examined by field emission scanning electron microscopy and reveals homogeneous microstructure with two types of grains, smaller grains of the Ba{sub 0.95}Sr{sub 0.05}TiO{sub 3} (BST) and bigger grains of the CoFe{sub 1.8}Mn{sub 0.2}O{sub 4} (CFM). The dielectric studies show that all the composites exhibit dispersion in the lower frequency region attributable to the interfacial polarization. In addition, at lower frequencies, the dielectric constant (?) is found to increase with increase in CFM content in the composites. The ferromagnetic properties of the composites improve with the increase in the CFM content.

  20. High antiferromagnetic transition temperature of a honeycomb compound SrRu<sub>2sub>O>6sub>

    SciTech Connect (OSTI)

    Tian, Wei; Svoboda, Chris; Ochi, M.; Matsuda, M.; Cao, Huibo; Cheng, J. -G.; Sales, B. C.; Mandrus, D.; Arita, R.; Trivedi, Nandini; Yan, Jiaqiang

    2015-09-14

    We study the high-temperature magnetic order in a quasi-two-dimensional honeycomb compound SrRu<sub>2sub>O>6sub> by measuring magnetization and neutron powder diffraction with both polarized and unpolarized neutrons. SrRu<sub>2sub>O>6sub> crystallizes into the hexagonal lead antimonate (PbSb<sub>2sub>O>6sub>, space group P31m) structure with layers of edge-sharing RuO6 octahedra separated by Sr2+ ions. SrRu<sub>2sub>O>6sub> is found to order at T<sub>N> = 565 K with Ru moments coupled antiferromagnetically both in plane and out of plane. The magnetic moment is 1.30(2) ?<sub>B>/Ru at room temperature and is along the crystallographic c axis in the G-type magnetic structure. We perform density functional calculations with constrained random-phase approximation (RPA) to obtain the electronic structure and effective intra- and interorbital interaction parameters. The projected density of states shows strong hybridization between Ru 4d and O 2p. By downfolding to the target t<sub>2gsub> bands we extract the effective magnetic Hamiltonian and perform Monte Carlo simulations to determine the transition temperature as a function of interand intraplane couplings. We find a weak interplane coupling, 3% of the strong intraplane coupling, permits three-dimensional magnetic order at the observed T<sub>N> .

  1. FT-IR and thermoluminescence investigation of P{sub 2}O{sub 5}-BaO-K{sub 2}O glass system

    SciTech Connect (OSTI)

    Ivascu, C.; Timar-Gabor, A.; Cozar, O.

    2013-11-13

    The 0.5P{sub 2}O{sub 5}⋅xBaO⋅(0.5−x)K{sub 2}O glass system (0≤x≤0.5mol%) is investigated by FT-IR and thermoluminescence as a possible dosimetic material. FT-IR spectra show structural network modifications with the composition variations of the studied glasses. The predominant absorption bands are characterized by two broad peaks near 500 cm{sup −1}, two weak peaks around 740 cm{sup −1} and three peaks in the 900–1270 cm{sup −1} region. The shift in the position of the band assigned to asymmetric stretching of PO{sub 2}{sup −} group, υ{sub as}(PO{sub 2}{sup −}) modes from ∼1100 cm{sup −1} to 1085 cm{sup −1} and the decrease in its relative intensity with the increasing of K{sub 2}O content shows a network modifier role of this oxide.. Luminescence investigations show that by adding modifier oxides in the phosphate glass a dose dependent TL signals result upon irradiation. Thus P{sub 2}O{sub 5}–BaO–K{sub 2}O glass system is a possible candidate material for dosimetry in the dose 0 – 50 Gy range.

  2. Observation of the Decay B??D<sub>s(*)+K?l????l>

    SciTech Connect (OSTI)

    del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Battaglia, M.; Brown, D. N.; Hooberman, B.; Kerth, L. T.; Kolomensky, Yu. G.; Lynch, G.; Osipenkov, I. L.; Tanabe, T.; Hawkes, C. M.; Watson, A. T.; Koch, H.; Schroeder, T.; Asgeirsson, D. J.; Hearty, C.; Mattison, T. S.; McKenna, J. A.; Khan, A.; Randle-Conde, A.; Blinov, V. E.; Buzykaev, A. R.; Druzhinin, V. P.; Golubev, V. B.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Todyshev, K. Yu.; Yushkov, A. N.; Bondioli, M.; Curry, S.; Kirkby, D.; Lankford, A. J.; Mandelkern, M.; Martin, E. C.; Stoker, D. P.; Atmacan, H.; Gary, J. W.; Liu, F.; Long, O.; Vitug, G. M.; Campagnari, C.; Hong, T. M.; Kovalskyi, D.; Richman, J. D.; Eisner, A. M.; Heusch, C. A.; Kroseberg, J.; Lockman, W. S.; Martinez, A. J.; Schalk, T.; Schumm, B. A.; Seiden, A.; Winstrom, L. O.; Cheng, C. H.; Doll, D. A.; Echenard, B.; Hitlin, D. G.; Ongmongkolkul, P.; Porter, F. C.; Rakitin, A. Y.; Andreassen, R.; Dubrovin, M. S.; Mancinelli, G.; Meadows, B. T.; Sokoloff, M. D.; Bloom, P. C.; Ford, W. T.; Gaz, A.; Nagel, M.; Nauenberg, U.; Smith, J. G.; Wagner, S. R.; Ayad, R.; Toki, W. H.; Jasper, H.; Karbach, T. M.; Merkel, J.; Petzold, A.; Spaan, B.; Wacker, K.; Kobel, M. J.; Schubert, K. R.; Schwierz, R.; Bernard, D.; Verderi, M.; Clark, P. J.; Playfer, S.; Watson, J. E.; Andreotti, M.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Cecchi, A.; Cibinetto, G.; Fioravanti, E.; Franchini, P.; Luppi, E.; Munerato, M.; Negrini, M.; Petrella, A.; Piemontese, L.; Baldini-Ferroli, R.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Nicolaci, M.; Pacetti, S.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Rama, M.; Zallo, A.; Contri, R.; Guido, E.; Lo Vetere, M.; Monge, M. R.; Passaggio, S.; Patrignani, C.; Robutti, E.; Tosi, S.; Bhuyan, B.; Prasad, V.; Lee, C. L.; Morii, M.; Adametz, A.; Marks, J.; Schenk, S.; Uwer, U.; Bernlochner, F. U.; Ebert, M.; Lacker, H. M.; Lueck, T.; Volk, A.; Dauncey, P. D.; Tibbetts, M.; Behera, P. K.; Mallik, U.; Chen, C.; Cochran, J.; Crawley, H. B.; Dong, L.; Meyer, W. T.; Prell, S.; Rosenberg, E. I.; Rubin, A. E.; Gao, Y. Y.; Gritsan, A. V.; Guo, Z. J.; Arnaud, N.; Davier, M.; Derkach, D.; Firmino da Costa, J.; Grosdidier, G.; Le Diberder, F.; Lutz, A. M.; Malaescu, B.; Perez, A.; Roudeau, P.; Schune, M. H.; Serrano, J.; Sordini, V.; Stocchi, A.; Wang, L.; Wormser, G.; Lange, D. J.; Wright, D. M.; Bingham, I.; Chavez, C. A.; Coleman, J. P.; Fry, J. R.; Gabathuler, E.; Gamet, R.; Hutchcroft, D. E.; Payne, D. J.; Touramanis, C.; Bevan, A. J.; Di Lodovico, F.; Sacco, R.; Sigamani, M.; Cowan, G.; Paramesvaran, S.; Wren, A. C.; Brown, D. N.; Davis, C. L.; Denig, A. G.; Fritsch, M.; Gradl, W.; Hafner, A.; Alwyn, K. E.; Bailey, D.; Barlow, R. J.; Jackson, G.; Lafferty, G. D.; West, T. J.; Anderson, J.; Cenci, R.; Jawahery, A.; Roberts, D. A.; Simi, G.; Tuggle, J. M.; Dallapiccola, C.; Salvati, E.; Cowan, R.; Dujmic, D.; Fisher, P. H.; Sciolla, G.; Zhao, M.; Lindemann, D.; Patel, P. M.; Robertson, S. H.; Schram, M.; Biassoni, P.; Lazzaro, A.; Lombardo, V.; Palombo, F.; Stracka, S.; Cremaldi, L.; Godang, R.; Kroeger, R.; Sonnek, P.; Summers, D. J.; Nguyen, X.; Simard, M.; Taras, P.; De Nardo, G.; Monorchio, D.; Onorato, G.; Sciacca, C.; Raven, G.; Snoek, H. L.; Jessop, C. P.; Knoepfel, K. J.; LoSecco, J. M.; Wang, W. F.; Corwin, L. A.; Honscheid, K.; Kass, R.; Morris, J. P.; Rahimi, A. M.; Blount, N. L.; Brau, J.; Frey, R.; Igonkina, O.; Kolb, J. A.; Rahmat, R.; Sinev, N. B.; Strom, D.; Strube, J.; Torrence, E.; Castelli, G.; Feltresi, E.; Gagliardi, N.; Margoni, M.; Morandin, M.; Posocco, M.; Rotondo, M.; Simonetto, F.; Stroili, R.; Ben-Haim, E.; Bonneaud, G. R.; Briand, H.; Calderini, G.; Chauveau, J.; Hamon, O.; Leruste, Ph.; Marchiori, G.; Ocariz, J.; Prendki, J.; Sitt, S.; Biasini, M.; Manoni, E.; Rossi, A.; Angelini, C.; Batignani, G.; Bettarini, S.; Carpinelli, M.; Casarosa, G.; Cervelli, A.; Forti, F.; Giorgi, M. A.; Lusiani, A.; Neri, N.; Paoloni, E.; Rizzo, G.; Walsh, J. J.; Lopes Pegna, D.; Lu, C.; Olsen, J.; Smith, A. J. S.; Telnov, A. V.; Anulli, F.; Baracchini, E.; Cavoto, G.; Faccini, R.; Ferrarotto, F.; Ferroni, F.; Gaspero, M.; Li Gioi, L.; Mazzoni, M. A.; Piredda, G.; Renga, F.; Hartmann, T.; Leddig, T.; Schrder, H.; Waldi, R.; Adye, T.; Franek, B.; Olaiya, E. O.; Wilson, F. F.; Emery, S.; Hamel de Monchenault, G.; Vasseur, G.; Yche, Ch.; Zito, M.; Allen, M. T.; Aston, D.; Bard, D. J.; Bartoldus, R.; Benitez, J. F.; Cartaro, C.; Convery, M. R.; Dorfan, J.; Dubois-Felsmann, G. P.; Dunwoodie, W.; Field, R. C.; Franco Sevilla, M.; Fulsom, B. G.; Gabareen, A. M.; Graham, M. T.; Grenier, P.; Hast, C.; Innes, W. R.

    2011-07-22

    We report the observation of the decay B??D<sub>s(*)+K?l??l> based on 342fb? of data collected at the ?(4S) resonance with the BABAR detector at the PEP-II e?e? storage rings at SLAC. A simultaneous fit to three D+s decay chains is performed to extract the signal yield from measurements of the squared missing mass in the B meson decay. We observe the decay B??D<sub>s(*)+K?l??l> with a significance greater than 5 standard deviations (including systematic uncertainties) and measure its branching fraction to be B(B??D<sub>s(*)+K?l??l>)=[6.13+1.04<sub>-1.03sub>(stat)0.43(syst)0.51(B(D<sub>s>))]10??, where the last error reflects the limited knowledge of the D<sub>s> branching fractions.

  3. Spontaneous formation of suboxidic coordination around Co in ferromagnetic rutile Ti<sub>0.95sub>Co>0.5sub>O>2sub> film

    SciTech Connect (OSTI)

    Hu, Wen; Hayaski, Kouichi; Fukumura, Tomoteru; Akagi, Kazuto; Tsukada, Masaru; Happo, Naohisa; Hosokawa, Shinya; Ohwada, Kenji; Takahasi, Masamitu; Suzuki, Motohiro

    2015-06-02

    To evaluate local atomic structures around Co in high temperature diluted ferromagnetic semiconductor Co-doped TiO<sub>2sub>, x-ray fluorescence holography and x-ray absorption fine structure experiments were carried out on rutile paramagnetic Ti<sub>0.99sub>Co>0.01sub>O>2sub> and ferromagnetic Ti<sub>0.95sub>Co>0.05sub>O>2sub> films. The Co atoms in the Ti<sub>0.99sub>Co>0.01sub>O>2sub> simply substituted for Ti sites in the rutile structure, whereas a suboxidic arrangement of CoO<sub>2sub>Ti>4sub> formed around Co in the Ti<sub>0.95sub>Co>0.05sub>O>2sub> films. A theoretical investigation based on a series of first-principles calculations indicated the stability of the aggregated suboxidic clusters in the rutile TiO<sub>2sub>, supporting our hypothesis for the formation of suboxidic coordination in the highly Co-doped sample. As a result, the suboxidic coordination may be the source of strong exchange interaction, resulting in the high Curie temperature in Co-doped TiO<sub>2sub>.

  4. Extraordinary selectivity of CoMo{sub 3}S{sub 13} chalcogel for C{sub 2}H{sub 6} and CO{sub 2} adsorption.

    SciTech Connect (OSTI)

    Shafaei-Fallah, M.; Rothenberger, Z.; Katsoulidis, A. P.; He, J.; Malliakas, C. D.; Kanatzidis, M. G.

    2011-11-09

    The chalcogel CoMo{sub 3}S{sub 13} is obtained from the reaction of (NH{sub 4}){sub 2}[Mo{sub 3}S{sub 13}] with cobalt acetate in solution. The chalcogel has a BET surface area of 570 m{sup 2} g{sup -1}, and pair distribution function analysis (PDF) and infrared spectroscopy indicate that the [Mo{sub 3}S{sub 13}]{sup 2-} cluster is a building block in the porous network. The CoMo{sub 3}S{sub 13} chalcogel exhibits high selectivity for separating ethane and carbon dioxide from hydrogen and methane.

  5. Order-disorder transition in the Nd{sub 2-y}Y{sub y}Zr{sub 2}O{sub 7} system: Probed by X-ray diffraction and Raman spectroscopy

    SciTech Connect (OSTI)

    Mandal, B.P.; Krishna, P.S.R.; Tyagi, A.K.

    2010-01-15

    A series of compositions having the general formula Nd{sub 2-y}Y{sub y}Zr{sub 2}O{sub 7} have been synthesized by heating of mixtures of oxides of the components cation and characterized by X-ray diffraction and Raman spectroscopy. Rietveld analysis on the XRD data of all the compositions has been performed which revealed a decrease in lattice parameter as a function of y in the series Nd{sub 2-y}Y{sub y}Zr{sub 2}O{sub 7} (y=0.0-0.8). Subsequently, a biphasic region starts which continues for y=1.2 and 1.6. The other end member, i.e. Y{sub 2}Zr{sub 2}O{sub 7} is found to be defect fluorite. On the other hand, Nd{sup 3+} has been used as surrogate material for Am{sup 3+}, which is a minor actinide found in spent nuclear fuel. In the pyrochlore range, the increasing trend of the x-parameter of 48f oxygen indicates the enhancement of disorder in the system. Raman spectroscopy has been employed to validate the data obtained from XRD. The involvement of 48f oxygen in disorder has also been verified by Raman spectroscopic investigation. - Graphical abstract: In Nd{sub 2-y}Y{sub y}Zr{sub 2}O{sub 7} series, the structure changes from pyrochlore to defect fluorite with increase in Y content in the series. The Raman spectra explicitly shows how the structural changes take place in the system.

  6. Stripe-like nanoscale structural phase separation in superconducting BaPb<sub>1-xsub>BixO>3sub>

    SciTech Connect (OSTI)

    Giraldo-Gallo, P.; Zhang, Y.; Parra, C.; Manoharan, H. C.; Beasley, M. R.; Geballe, T. H.; Kramer, M. J.; Fisher, I. R.

    2015-09-16

    The phase diagram of BaPb<sub>1-xsub>BixO>3sub> exhibits a superconducting “dome” in the proximity of a charge density wave phase. For the superconducting compositions, the material coexists as two structural polymorphs. Here we show, via high resolution transmission electron microscopy, that the structural dimorphism is accommodated in the form of partially disordered nanoscale stripes. Identification of the morphology of the nanoscale structural phase separation enables determination of the associated length scales, which we compare to the Ginzburg-Landau coherence length. Thus, we find that the maximum T<sub>c> occurs when the superconducting coherence length matches the width of the partially disordered stripes, implying a connection between the structural phase separation and the shape of the superconducting dome.

  7. Aqueous Sulfate Separation by Sequestration of [(SO<sub>4sub>)>2sub>(H>2sub>O)>4sub>]>4sub> Clusters within Highly Insoluble Imine-Linked Bis-Guanidinium Crystals

    SciTech Connect (OSTI)

    Custelcean, Radu; Williams, Neil J.; Seipp, Charles A.; Ivanov, Aleksandr; Bryantsev, Vyacheslav

    2015-12-18

    Quantitative removal of sulfate from seawater was achieved by selective crystallization of the anion with a bis(guanidinium) ligand self-assembled in situ through imine condensation of simple components. The resulting crystalline salt has an exceptionally low aqueous solubility, on a par with BaSO<sub>4sub>. Single-crystal X-ray diffraction analysis revealed pairs of sulfate anions clustered together with four water molecules within the crystals.

  8. Stabilized wide bandgap MAPbBr<sub>xI>3-xsub> perovskite by enhanced grain size and improved crystallinity

    SciTech Connect (OSTI)

    Hu, Miao; Bi, Cheng; Yuan, Yongbo; Bai, Yang; Huang, Jinsong

    2015-12-07

    In this study, the light instability of CH<sub>3sub>NH>3sub>PbIxBr>3xsub> has been raised one of the biggest challenges for its application in tandem solar cells. Here we show that an improved crystallinity and grain size of CH<sub>3sub>NH>3sub>PbIxBr>3xsub> films could stabilize these materials under one sun illumination, improving both the efficiency and stability of the wide-bandgap perovskite solar cells.

  9. Final Report: Northeastern Regional Center of the DOE's National Institute for Climatic Change Research

    SciTech Connect (OSTI)

    Davis, Kenneth

    2014-01-14

    Administration of the NERC of NICCR began at Penn State in December of 2005 and ended in December of 2011. During that time, five requests for proposals were released and five rounds of proposals were reviewed, awarded and administered. Throughout this award, 203 pre-proposals have been received by the NERC in five RFPS and 110 full proposals invited. Of the 110 full proposals reviewed, 53 were funded (most in full, some partially) resulting in 51 subcontracts. These awards were distributed among 17 universities and 3 non-governmental research institutes. Full proposals have been received from 29 universities and 5 non-governmental research institutes. Research activities have now been completed.

  10. Preparation of U.sub.3 O.sub.8

    DOE Patents [OSTI]

    Johnson, David R.

    1980-01-01

    A method is described for the preparation of U.sub.3 O.sub.8 nuclear fuel material by direct precipitation of uranyl formate monohydrate from uranyl nitrate solution. The uranyl formate monohydrate precipitate is removed, dried and calcined to produce U.sub.3 O.sub.8 having a controlled particle size distribution.

  11. Investigation of the phase equilibria and phase transformations associated with the Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub y} superconductor

    SciTech Connect (OSTI)

    Holesinger, T.

    1993-12-09

    The solid solution region and reaction kinetics of the Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub y} (2212) superconductor were examined as a function of temperature and oxygen partial pressure. Crystallization studies from the glassy and molten states were undertaken to determine the phase transformation and kinetics associated with the formation of 2212 and other competing phases. Crystallization of nominal 2212 glasses was found to proceed in two steps with the formation of Bi{sub 2}Sr{sub 2{minus}x}Ca{sub x}CuO{sub y} (2201) and Cu{sub 2}O followed by Bi{sub 2}Sr{sub 3{minus}x}Ca{sub x}O{sub y}, CaO, and SrO. The 2212 phase converts from the 2201 phase with increasing temperatures. However, its formation below 800 C was kinetically limited. At 800 C and above, a nearly full conversion to the 2212 phase was achieved after only one minute although considerably longer anneal times were necessary for the system to reach equilibrium. In low oxygen partial pressures, the solidus is reduced to approximately 750 C. Solidification studies revealed an eutectic structure separating the incongruently melting 2212/2201 phases at high oxygen partial pressures from the congruently melting Bi{sub 2}Sr{sub 3{minus}x}Ca{sub x}O{sub y} (23x) and Bi{sub 2}Sr{sub 2{minus}x}Ca{sub x}O{sub y} (22x) phases present at low oxygen partial pressures. During solidification in various oxygen partial pressures, the separation of CaO in the melt and the initial crystallization of alkaline-earth cuprates leaves behind a Bi-rich liquid from which it is impossible to form single-phase 2212. Hence, significant amounts of 2201 were also present in these samples. These problems could be reduced by melt processing in inert atmospheres. Bulk 2212 material produced in this manner was found to possess high transition temperatures, high intergranular critical current densities below 20K, and modest critical current densities at 77K.

  12. The (111) Surface of NaAu<sub>2sub>. Structure, Composition, and Stability

    SciTech Connect (OSTI)

    Kwolek, Emma J.; Widmer, Roland; Gröning, Oliver; Deniz, Okan; Walen, Holly; Yuen, Chad D.; Huang, Wenyu; Schlagel, Deborah L.; Wallingford, Mark; Thiel, Patricia A.

    2014-12-17

    The (111) surface of single-crystal NaAu<sub>2sub> is a model for catalytically active, powdered NaAu<sub>2sub>. We prepare and characterize this surface with a broad suite of techniques. Preparation in ultrahigh vacuum consists of the traditional approach of ion bombardment (to remove impurities) and thermal annealing (to restore surface order). Both of these steps cause loss of sodium (Na), and repeated treatments eventually trigger conversion of the surface and near-surface regions to crystalline gold. The bulk has a limited ability to repopulate the surface Na. Under conditions where Na depletion is minimized, electron diffraction patterns are consistent with the bulk-terminated structure, and scanning tunneling microscopy reveals mesa-like features with lateral dimensions of a few tens of nanometers. The tops of the mesas do not possess fine structure characteristic of a periodic lattice, suggesting that the surface layer is disordered under the conditions of these experiments.

  13. A study of Zn<sub>xsub>ZryOz> mixed oxides for direct conversion of ethanol to isobutene

    SciTech Connect (OSTI)

    Liu, Changjun; Sun, Junming; Smith, Colin; Wang, Yong

    2013-07-15

    Zn<sub>xsub>ZryOz> mixed oxides were studied for direct conversion of ethanol to isobutene. Reaction conditions (temperature, residence time, ethanol molar fraction, steam to carbon ratio), catalyst composition, and pretreatment conditions were investigated, aiming at high-yield production of isobutene under industrially relevant conditions. An isobutene yield of 79% was achieved with an ethanol molar fraction of 8.3% at 475 °C on fresh Zn<sub>1sub>Zr>8sub>O>17sub> catalysts. Further durability and regeneration tests revealed that the catalyst exhibited very slow deactivation via coking formation with isobutene yield maintained above 75% for more than 10 h time-on-stream. More importantly, the catalysts activity in terms of isobutene yield can be readily recovered after in situ calcination in air at 550 °C for 2.5 h. XRD, TPO, IR analysis of adsorbed pyridine (IR-Py), and nitrogen sorption have been used to characterize the surface physical/chemical properties to correlate the structure and performance of the catalysts.

  14. Thermal stability and transport studies of (100 - 2x)TeO{sub 2}-xAg{sub 2}O-xWO{sub 3} (7.5 {<=} x {<=} 30) glass system

    SciTech Connect (OSTI)

    Upender, G.; Ramesh, Ch.; Mouli, V. Chandra

    2011-02-15

    Graphical abstract: Typical modulated DSC (NRHF and C{sub p}) results during a heating scan in the 85TeO{sub 2}-7.5Ag{sub 2}O-7.5WO{sub 3} glass sample. Research highlights: {yields} The addition of equal mol% of WO{sub 3} and Ag{sub 2}O to TeO{sub 2} increases the thermal stability. {yields} The 55TeO{sub 2}-22.5WO{sub 3}-22.5Ag{sub 2}O shows the highest thermal stability ({Delta}T = 237 {sup o}C). {yields} These glasses are more useful for drawing of optical fibers. {yields} The present glass system shows higher conductivity. -- Abstract: Differential scanning calorimetry (DSC), infrared (IR) and direct current (DC) conductivity studies have been carried out on (100 - 2x)TeO{sub 2}-xAg{sub 2}O-xWO{sub 3} (7.5 {<=} x {<=} 30) glass system. The IR studies show that the structure of glass network consists of [TeO{sub 4}], [TeO{sub 3}]/[TeO{sub 3+1}], [WO{sub 4}] units. Thermal properties such as the glass transition (T{sub g}), onset crystallization (T{sub o}), thermal stability ({Delta}T), glass transition width ({Delta}T{sub g}), heat capacities in the glassy and liquid state (C{sub pg} and C{sub pl}), heat capacity change ({Delta}C{sub p}) and ratios C{sub pl}/C{sub pg} of the glass systems were calculated. The highest thermal stability (237 {sup o}C) obtained in 55TeO{sub 2}-22.5Ag{sub 2}O-22.5WO{sub 3} glass suggests that this new glass may be a potentially useful candidate material host for rare earth doped optical fibers. The DC conductivity of glasses was measured in temperature region 27-260 {sup o}C, the activation energy (E{sub act}) values varied from 1.393 to 0.272 eV and for the temperature interval 170-260 {sup o}C, the values of conductivity ({sigma}) of glasses varied from 8.79 x 10{sup -9} to 1.47 x 10{sup -6} S cm{sup -1}.

  15. North America's net terrestrial CO<sub>2sub> exchange with the atmosphere 1990–2009

    SciTech Connect (OSTI)

    King, Anthony W.; Andres, Robert; Davis, Kenneth J.; Hafer, M.; Hayes, Daniel J.; Huntzinger, Deborah N.; de Jong, Bernardus; Kurz, Werner; McGuire, A. David; Vargas, Rodrigo; Wei, Yaxing; West, Tristram O.; Woodall, Chris W.

    2015-01-21

    Scientific understanding of the global carbon cycle is required for developing national and international policy to mitigate fossil fuel CO<sub>2sub> emissions by managing terrestrial carbon uptake. Toward that understanding and as a contribution to the REgional Carbon Cycle Assessment and Processes (RECCAP) project, this paper provides a synthesis of net land–atmosphere CO<sub>2sub> exchange for North America (Canada, United States, and Mexico) over the period 1990–2009. Only CO<sub>2sub> is considered, not methane or other greenhouse gases. This synthesis is based on results from three different methods: atmospheric inversion, inventory-based methods and terrestrial biosphere modeling. All methods indicate that the North American land surface was a sink for atmospheric CO<sub>2sub>, with a net transfer from atmosphere to land. Estimates ranged from -890 to -280 Tg C yr-1, where the mean of atmospheric inversion estimates forms the lower bound of that range (a larger land sink) and the inventory-based estimate using the production approach the upper (a smaller land sink). This relatively large range is due in part to differences in how the approaches represent trade, fire and other disturbances and which ecosystems they include. Integrating across estimates, \\"best\\" estimates (i.e., measures of central tendency) are -472 ± 281 Tg C yr-1 based on the mean and standard deviation of the distribution and -360 Tg C yr-1 (with an interquartile range of -496 to -337) based on the median. Considering both the fossil fuel emissions source and the land sink, our analysis shows that North America was, however, a net contributor to the growth of CO<sub>2sub> in the atmosphere in the late 20th and early 21st century. With North America's mean annual fossil fuel CO<sub>2sub> emissions for the period 1990–2009 equal to 1720 Tg C yr-1 and assuming the estimate of -472 Tg C yr-1 as an approximation of the true terrestrial CO<sub>2sub> sink, the continent's source : sink ratio for this time period was 1720:472, or nearly 4:1.

  16. Structural and optical properties of Ga{sub 2}O{sub 3}:In films deposited on MgO (1 0 0) substrates by MOCVD

    SciTech Connect (OSTI)

    Kong Lingyi; Ma Jin; Luan Caina; Zhu Zhen

    2011-08-15

    Ga{sub 2}O{sub 3}:In films with different indium (In) content x [x=In/(Ga+In) atomic ratio] have been deposited on MgO (1 0 0) substrates by metalorganic chemical vapor deposition (MOCVD). Structural analyses revealed that the film deposited with actual In content (x') of 0.09 was an epitaxial film and the films with x'=0.18 and 0.37 had mixed-phase structures of monoclinic Ga{sub 2}O{sub 3} and bixbyite In{sub 2}O{sub 3}. The absolute average transmittance of the obtained films in the visible region exceeded 95%, and the band gap was in the range of 4.74-4.87 eV. Photoluminescence (PL) measurements were performed at room temperature, in which the visible luminescences were strong and could be seen by the naked eye. The strong emissions in the visible light region were proposed to originate from the gallium vacancies, oxygen deficiencies and other defects in these films. - Graphical abstract: Low magnification XTEM (a), HRTEM (b) and SAED (c) micrographs of the interface area between Ga{sub 1.82}In{sub 0.18}O{sub 3} film and MgO substrate have showed the Ga{sub 1.82}In{sub 0.18}O{sub 3} is an epitaxial film. Highlights: > Ga{sub 1.82}In{sub 0.18}O{sub 3} epitaxial film was deposited on MgO(1 0 0) substrate. > The transmittance of the Ga{sub 2}O{sub 3}:In films in the visible region exceeded 95%. > Strong emissions were observed in the photoluminescence measurements of the films.

  17. Fluorocarbon assisted atomic layer etching of SiO<sub>2sub> and Si using cyclic Ar/C<sub>4sub>F>8sub> and Ar/CHF<sub>3sub> plasma

    SciTech Connect (OSTI)

    Metzler, Dominik; Li, Chen; Engelmann, Sebastian; Bruce, Robert L.; Joseph, Eric A.; Oehrlein, Gottlieb S.

    2015-11-11

    The need for atomic layer etching (ALE) is steadily increasing as smaller critical dimensions and pitches are required in device patterning. A flux-control based cyclic Ar/C<sub>4sub>F>8sub> ALE based on steady-state Ar plasma in conjunction with periodic, precise C<sub>4sub>F>8sub> injection and synchronized plasma-based low energy Ar+ ion bombardment has been established for SiO<sub>2sub>.1 In this work, the cyclic process is further characterized and extended to ALE of silicon under similar process conditions. The use of CHF<sub>3sub> as a precursor is examined and compared to C<sub>4sub>F>8sub>. CHF<sub>3sub> is shown to enable selective SiO<sub>2sub>/Si etching using a fluorocarbon (FC) film build up. Other critical process parameters investigated are the FC film thickness deposited per cycle, the ion energy, and the etch step length. Etching behavior and mechanisms are studied using in situ real time ellipsometry and X-ray photoelectron spectroscopy. Silicon ALE shows less self-limitation than silicon oxide due to higher physical sputtering rates for the maximum ion energies used in this work, ranged from 20 to 30 eV. The surface chemistry is found to contain fluorinated silicon oxide during the etching of silicon. As a result, plasma parameters during ALE are studied using a Langmuir probe and establish the impact of precursor addition on plasma properties.

  18. SAS Output

    Gasoline and Diesel Fuel Update (EIA)

    Peak Load by North American Electric Reliability Corporation Assessment Area, 2004 - ... Notes: NERC region and reliability assessment area maps are provided on EIA's Electricity ...

  19. Word Pro - Untitled1

    Gasoline and Diesel Fuel Update (EIA)

    Noncoincident Peak Load 1 by North American Electric Reliability Corporation (NERC) 2 ... and SPP regional boundaries were altered as utilities changed reliability organizations. ...

  20. SAS Output

    Annual Energy Outlook [U.S. Energy Information Administration (EIA)]

    Margins by North American Electric Reliability Assessment Area, 2004 - 2014, Actual ... Notes: NERC region and reliability assessment area maps are provided on EIA's Electricity ...

  1. RAPID/BulkTransmission/Montana | Open Energy Information

    Open Energy Info (EERE)

    Western Interconnection power grids and is part of two NERC regions - the Midwest Reliability Organization (MRO) and Western Electricity Coordinating Council (WECC). MRO's...

  2. EIA-411 Data File

    U.S. Energy Information Administration (EIA) Indexed Site

    historic data Electric Reliability Historic Data Release Date: May 16, 2016 Next Release Date: November 2016 Electricity Reliability Data Shown by NERC Council and Region formats ...

  3. SOUTHWEST REGIONAL PARTNERSHIP FOR CARBON SEQUESTRATION

    SciTech Connect (OSTI)

    Brian McPherson

    2004-04-01

    The Southwest Partnership Region includes five states (Arizona, Colorado, New Mexico, Oklahoma, Utah) and contiguous areas from three adjacent states (west Texas, south Wyoming, and west Kansas). This energy-rich region exhibits some of the largest growth rates in the nation, and it contains two major CO{sub 2} pipeline networks that presently tap natural subsurface CO{sub 2} reservoirs for enhanced oil recovery at a rate of 30 million tons per year. The ten largest coal-fired power plants in the region produce 50% (140 million tons CO{sub 2}/y) of the total CO{sub 2} from power-plant fossil fuel combustion, with power plant emissions close to half the total CO{sub 2} emissions. The Southwest Regional Partnership comprises a large, diverse group of expert organizations and individuals specializing in carbon sequestration science and engineering, as well as public policy and outreach. These partners include 21 state government agencies and universities, the five major electric utility industries, seven oil, gas and coal companies, three federal agencies, the Navajo Nation, several NGOs including the Western Governors Association, and data sharing agreements with four other surrounding states. The Partnership is developing action plans for possible Phase II carbon sequestration pilot tests in the region, as well as the non-technical aspects necessary for developing and carrying out these pilot tests. The establishment of a website network to facilitate data storage and information sharing, decision-making, and future management of carbon sequestration in the region is a priority. The Southwest Partnership's approach includes (1) dissemination of existing regulatory/permitting requirements, (2) assessing and initiating public acceptance of possible sequestration approaches, and (3) evaluation and ranking of the most appropriate sequestration technologies for capture and storage of CO{sub 2} in the Southwest Region. The Partnership will also identify potential gaps in monitoring and verification approaches needed to validate long-term storage efforts.

  4. Dual nature of 3 d electrons in YbT <sub>2sub> Zn <sub>20sub> (T = Co; Fe) evidenced by electron spin resonance

    SciTech Connect (OSTI)

    Ivanshin, V. A.; Litvinova, T. O.; Gimranova, K.; Sukhanov, A. A.; Jia, S.; Bud'ko, S. L.; Canfield, P. C.

    2015-03-18

    The electron spin resonance experiments were carried out in the single crystals YbFe<sub>2sub>Zn>20sub>. The observed spin dynamics is compared with that in YbCo<sub>2sub>Zn>20sub> and Yb<sub>2sub>Co>12sub>P>7sub> as well as with the data of inelastic neutron scattering and electronic band structure calculations. Our results provide direct evidence that 3d electrons are itinerant in YbFe<sub>2sub>Zn>20sub> and localized in YbCo<sub>2sub>Zn>20sub>. Possible connection between spin paramagnetism of dense heavy fermion systems, quantum criticality effects, and ESR spectra is discussed.

  5. CaMn<sub>2sub>Al>10sub>: Itinerant Mn magnetism on the verge of magnetic order

    SciTech Connect (OSTI)

    Steinke, L.; Simonson, J. W.; Yin, W. -G.; Smith, G. J.; Kistner-Morris, J. J.; Zellman, S.; Puri, A.; Aronson, M. C.

    2015-07-24

    We report the discovery of CaMn<sub>2sub>Al>10sub>, a metal with strong magnetic anisotropy and moderate electronic correlations. Magnetization measurements find a Curie-Weiss moment of 0.83<sub>μB>/Mn, significantly reduced from the Hund's rule value, and the magnetic entropy obtained from specific heat measurements is correspondingly small, only ≈ 9% of Rln2. These results imply that the Mn magnetism is highly itinerant, a conclusion supported by density functional theory calculations that find strong Mn-Al hybridization. Consistent with the layered nature of the crystal structure, the magnetic susceptibility χ is anisotropic below 20 K, with a maximum ratio of χ<sub>[010]sub>/χ>[001]sub> ≈ 3.5. A strong power-law divergence χ(T) ~ T–1.2 below 20 K implies incipient ferromagnetic order, an Arrott plot analysis of the magnetization suggests a vanishing low Curie temperature T<sub>C> ~ 0. Our experiments indicate that CaMn<sub>2sub>Al>10sub> is a rare example of a system where the weak and itinerant Mn-based magnetism is poised on the verge of order.

  6. Defect-Tolerant Diffusion Channels for Mg2+ Ions in Ribbon-Type Borates: Structural Insights into Potential Battery Cathodes MgVBO<sub>4sub> and Mg<sub>x> Fe<sub>2–xsub>B>2sub>O>5sub>

    SciTech Connect (OSTI)

    Bo, Shou-Hang; Grey, Clare P.; Khalifah, Peter G.

    2015-06-10

    The reversible room temperature intercalation of Mg2+ ions is difficult to achieve, but may offer substantial advantages in the design of next-generation batteries if this electrochemical process can be successfully realized. Two types of quadruple ribbon-type transition metal borates (Mg<sub>xFe>2-xsub>B>2sub>O>5sub> and MgVBO<sub>4sub>) with high theoretical capacities (186 mAh/g and 360 mAh/g) have been synthesized and structurally characterized through the combined Rietveld refinement of synchrotron and time-of-flight neutron diffraction data. Neither MgVBO<sub>4 sub> nor Mg<sub>xFe>2-xsub>B>2sub>O>5sub> can be chemically oxidized at room temperature, though Mg can be dynamically removed from the latter phase at elevated temperatures (approximately 200 - 500 °C). Findings show that Mg diffusion in the Mg<sub>xFe>2-xsub>B>2sub>O>5sub> structure is more facile for the inner two octahedral sites than for the two outer octahedral sites in the ribbons, a result supported by both the refined site occupancies after Mg removal and by bond valence sum difference map calculations of diffusion paths in the pristine material. Mg diffusion in this pyroborate Mg<sub>xFe>2-xsub>B>2sub>O>5sub> framework is also found to be tolerant to the presence of Mg/Fe disorder since Mg ions can diffuse through interstitial channels which bypass Fe-containing sites.

  7. Controlled peak wavelength shift of Ca{sub 1-} {sub x} Sr {sub x} (S {sub y} Se{sub 1-} {sub y} ):Eu{sup 2+} phosphor for LED application

    SciTech Connect (OSTI)

    Nazarov, Mihail . E-mail: nazarov.mihail@samsung.com; Yoon, Chulsoo

    2006-08-15

    The highly efficient red-orange-yellow-emitting phosphor (Ca{sub 1-} {sub x} Sr {sub x} )(S{sub 1-} {sub y} Se {sub y} ):Eu{sup 2+} in combination with commercial green phosphor SrGa{sub 2}S{sub 4}:Eu{sup 2+} and blue LED are proposed for a three-band white LED. The luminescence mechanism and optimization parameters are discussed on the basis of proposed peak wavelength diagram. - Graphical abstract: 'Peak wavelength diagram for (Ca{sub 1-} {sub x} Sr {sub x} )(S{sub 1-} {sub y} Se {sub y} ):Eu{sup 2+}'.

  8. CF.sub.4 laser

    DOE Patents [OSTI]

    Wittig, Curt; Tiee, Joe J.

    1979-01-01

    A CF.sub.4 laser for producing near 16 .mu.m radiation utilizing a line tunable CO.sub.2 laser as an optical pumping source. The device uses a cryogenically cooled optically pumped cell containing molecular CF.sub.4 gas. An optical resonant cavity formed around the optically pumped cell induces oscillations of near 16 .mu.m radiation from the .nu..sub.2 +.nu..sub.4 .fwdarw..nu..sub.2 transition in the molecular CF.sub.4 gas.

  9. Magnetic structures of β{sub I}-Li{sub 2}CoSiO{sub 4} and γ{sub 0}-Li{sub

    Office of Scientific and Technical Information (OSTI)

    2}MnSiO{sub 4}: Crystal structure type vs. magnetic topology (Journal Article) | SciTech Connect Magnetic structures of β{sub I}-Li{sub 2}CoSiO{sub 4} and γ{sub 0}-Li{sub 2}MnSiO{sub 4}: Crystal structure type vs. magnetic topology Citation Details In-Document Search Title: Magnetic structures of β{sub I}-Li{sub 2}CoSiO{sub 4} and γ{sub 0}-Li{sub 2}MnSiO{sub 4}: Crystal structure type vs. magnetic topology The magnetic structure and properties of the candidate lithium-ion battery cathode

  10. Multi-functional ultrathin Pd<sub>xCu>1-xsub> and Pt~Pd<sub>xCu>1-xsub> one-dimensional nanowire motifs for various small molecule oxidation reactions

    SciTech Connect (OSTI)

    Liu, Haiqing; Wong, Stanislaus S.; Adzic, Radoslav R.

    2015-11-18

    Developing novel electrocatalysts for small molecule oxidation processes, including formic acid oxidation (FAOR), methanol oxidation reaction (MOR), and ethanol oxidation reaction (EOR), denoting the key anodic reactions for their respective fuel cell configurations, is a significant and relevant theme of recent efforts in the field. Herein, in this report, we demonstrated a concerted effort to couple and combine the benefits of small size, anisotropic morphology, and tunable chemical composition in order to devise a novel “family” of functional architectures. In particular, we have fabricated not only ultrathin 1-D Pd<sub>1–xsub>Cux> alloys but also Pt-coated Pd<sub>1–xsub>Cux> (i.e., Pt~Pd<sub>1–xsub>Cux>; herein the ~ indicates an intimate association, but not necessarily actual bond formation, between the inner bimetallic core and the Pt outer shell) core–shell hierarchical nanostructures with readily tunable chemical compositions by utilizing a facile, surfactant-based, wet chemical synthesis coupled with a Cu underpotential deposition technique. Our main finding is that our series of as-prepared nanowires are functionally flexible. More precisely, we demonstrate that various examples within this “family” of structural motifs can be tailored for exceptional activity with all 3 of these important electrocatalytic reactions. In particular, we note that our series of Pd<sub>1–xsub>Cux> nanowires all exhibit enhanced FAOR activities as compared with not only analogous Pd ultrathin nanowires but also commercial Pt and Pd standards, with Pd<sub>9sub>Cu representing the “optimal” composition. Moreover, our group of Pt~Pd<sub>1–xsub>Cux> nanowires consistently outperformed not only commercial Pt NPs but also ultrathin Pt nanowires by several fold orders of magnitude for both the MOR and EOR reactions in alkaline media. As a result, the variation of the MOR and EOR performance with the chemical composition of our ultrathin Pt~Pd<sub>1–xsub>Cux> nanowires was also discussed.

  11. Structural and magnetic phase transitions in CeCu<sub>6-xsub>Tx> (T = Ag,Pd)

    SciTech Connect (OSTI)

    Poudel, Lekhanath N.; De la cruz, Clarina; Payzant, E. Andrew; Koehler, Michael R.; May, Andrew F.; Garlea, Vasile O.; Taylor, Alice E.; Parker, David S.; Cao, Huibo B.; McGuire, Michael A.; Tian, Wei; Matsuda, Masaaki; Jeen, Hyoung Jeen; Lee, Ho Nyung; Hong, Tao; Calder, Stuart A.; Lumsden, Mark D.; Zhou, Haidong; Keppens, Veerle; Mandrus, D.; Christianson, Andrew D.

    2015-12-15

    The structural and the magnetic properties of CeCu<sub>6-xsub>Agx> (0 ≤ x ≤ 0.85) and CeCu<sub>6-xsub>Pdx> (0 ≤ x ≤ 0.4) have been studied using neutron diffraction, resonant ultrasound spectroscopy (RUS), x-ray diffraction measurements, and first principles calculations. The structural and magnetic phase diagrams of CeCu<sub>6-xsub>Agx> and CeCu<sub>6-xsub>Pdx> as a function of Ag/Pd composition are reported. The end member, CeCu<sub>6sub>, undergoes a structural phase transition from an orthorhombic (Pnma) to a monoclinic (P2<sub>1sub>/c) phase at 240 K. In CeCu<sub>6-xsub>Agx>, the structural phase transition temperature (T<sub>s>) decreases linearly with Ag concentration and extrapolates to zero at x<sub>S> ≈ 0.1. The structural transition in CeCu<sub>6-xsub>Pdx> remains unperturbed with Pd substitution within the range of our study. The lattice constant b slightly decreases with Ag/Pd doping, whereas a and c increase with an overall increase in the unit cell volume. Both systems, CeCu<sub>6-xsub>Agx> and CeCu<sub>6-xsub>Pdx>, exhibit a magnetic quantum critical point (QCP), at x ≈ 0.2 and x ≈ 0.05, respectively. Near the QCP, long range antiferromagnetic ordering takes place at an incommensurate wave vector (δ<sub>1sub> 0 δ<sub>2sub>), where δ<sub>1sub> ~ 0.62, δ<sub>2sub> ~ 0.25, x = 0.125 for CeCu<sub>6-xsub>Pdx> and δ<sub>1sub> ~ 0.64, δ<sub>2sub> ~ 0.3, x = 0.3 for CeCu<sub>6-xsub>Agx>. As a result, the magnetic structure consists of an amplitude modulation of the Ce moments which are aligned along the c axis of the orthorhombic unit cell.

  12. Structural features and enhanced high-temperature oxygen ion transport in SrFe{sub 1-x}Ta{sub x}O{sub 3-{delta}}

    SciTech Connect (OSTI)

    Markov, Alexey A.; Shalaeva, Elizaveta V.; Tyutyunnik, Alexander P.; Kuchin, Vasily V.; Patrakeev, Mikhail V.; Leonidov, Ilya A.; Kozhevnikov, Victor L.

    2013-01-15

    Structural features, oxygen non-stoichiometry and transport properties are studied in the oxide series SrFe{sub 1-x}Ta{sub x}O{sub 3-{delta}}, where x=0.2, 0.3 and 0.4. X-ray diffraction and electron microscopy data evidence formation of the inhomogeneous materials at x=0.3 and 0.4, which include phase constituents with a cubic perovskite and a double perovskite structure types. The composition, the amount and the typical grain size of the phase inhomogeneities are shown to depend both on doping and oxygen content. The increased oxygen-ion conductivity is observed in oxygen depleted materials, which is explained by the increase in the amount of cubic perovskite-like phase and development of interfacial pathways favorable for enhanced oxygen ion transport. - Graphical abstract: The structural studies, oxygen content and conductivity measurements suggest that oxygen depletion from the double perovskite phase constituent of SrFe{sub 1-x}Ta{sub x}O{sub 3-{delta}} for x>0.2 is accompanied by formation of pathways for fast ion transport. Black-Small-Square Highlights: Black-Right-Pointing-Pointer The double perovskite type regions are shown to exist in SrFe{sub 1-x}Ta{sub x}O{sub 3-{delta}}. Black-Right-Pointing-Pointer The oxygen depletion is accompanied with phase separation. Black-Right-Pointing-Pointer The phase separation favors formation of pathways for enhanced oxygen ion transport.

  13. Investigation on dielectric properties of atomic layer deposited Al{sub 2}O{sub 3} dielectric films

    SciTech Connect (OSTI)

    Y?ld?z, Dilber Esra; Y?ld?r?m, Mert; Gken, Muharrem

    2014-05-15

    Al/Al{sub 2}O{sub 3}/p-Si Schottky barrier diodes (SBDs) were fabricated using atomic layer deposition technique in order to investigate dielectric properties of SBDs. For this purpose, admittance measurements were conducted at room temperature between ?1?V and 3?V in the frequency range of 10 kHz and 1?MHz. In addition to the investigation of Al{sub 2}O{sub 3} morphology using atomic force microscope, dielectric parameters; such as dielectric constant (??), dielectric loss (??), dielectric loss tangent (tan??), and real and imaginary parts of dielectric modulus (M? and M?, respectively), were calculated and effect of frequency on these parameters of Al/Al{sub 2}O{sub 3}/p-Si SBDs was discussed. Variations in these parameters at low frequencies were associated with the effect of interface states in low frequency region. Besides dielectric parameters, ac electrical conductivity of these SBDs was also investigated.

  14. Lattice, Ce-L{sub 3}valence, transport, and magnetic results on mixed-valent/Kondo system Ce{sub 1{minus}x}La{sub x}Mn{sub 2}Si{sub 2}

    SciTech Connect (OSTI)

    Liang, G.; Xi, H.; Roberts, E.; Binford, T.; Mochizuki, K.; Markert, J.T.; Croft, M.

    1997-04-01

    Lattice, Ce-L{sub 3} edge, resistivity, and magnetic susceptibility measurements have been carried out on the polycrystalline Ce{sub 1{minus}x}La{sub x}Mn{sub 2}Si{sub 2} system (0{le}x{le}1) to study the interplay between Mn 3d-host magnetism and Kondo-type Ce-spin fluctuations. As x increases, the system varies gradually from a Ce mixed-valent system with 3d-host antiferromagnetism (at x=0) to a nearly trivalent system with strong 3d-host ferromagnetism (near x=1). In the antiferromagnetic (AF) phase region (0{le}x{le}0.5), the Neel temperature T{sub N} decreases with the increase of x, manifesting the weakening of the host AF field. Impurity Kondo behavior is observed at x=0.05, indicating that the low-temperature coherence state in CeMn{sub 2}Si{sub 2} can be destroyed by {open_quotes}Kondo holes{close_quotes} which are created by very small substitution of La for Ce. The susceptibility and resistivity results suggest that the impurity Kondo effect in the 0.1{le}x{le}0.5 samples is partially suppressed by a nonvanishing ferromagnetic (FM) field component; whereas the phononlike behavior of the resistivity curves in the Mn-host FM-phase region (0.5{lt}x{le}1.0) supports our previous proposal that the Kondo-type Ce-spin fluctuations can be effectively quenched by a strong 3d-host FM field. {copyright} {ital 1997 American Institute of Physics.}

  15. Transport and magnetization current in a thin layer of Bi{sub 1.8}Pb{sub 0.4}Sr{sub 2.0}Ca{sub 2.2}Cu{sub 3.0}O{sub y} adjacent to silver sheathing in BSCCO-2223 tapes

    SciTech Connect (OSTI)

    Lelovic, M.; Krishnaraj, P.; Deis, T.

    1995-07-01

    The thin superconducting region next to the silver sheath appears to be the region of high critical current density in BSCCO-2223 tapes. Transport current measurements on Bi{sub 1.8}Pb{sub 0.4}Sr{sub 2.0}Ca{sub 2.2}Cu{sub 3.0}O{sub y} tape at 77 K in a low magnetic field applied parallel to the tape thickness indicate an exponential field dependence [J / J{sub c} {proportional_to} exp (- B / B{sub 0})] for transport currents. Magnetic hysteresis was measured in a 10-{mu}m-thick layer of superconductor near the silver sheath as a function of temperature, intensity, and orientation of applied field with respect to the tape. The characteristic field for full penetration depth, B*, for a superconducting slab was found to have a power law dependence on temperature. Magnetization currents as a function of temperature and applied field oriented parallel to the tape thickness, J{sub c,m}(B,T), were determined from the magnetization loop width with a Bean- model expression adapted for an orthorhombic sample. The critical-state model, adjusted for scaling and magnetic relaxation, correlates well with the magnetization current of the thin layer at 77 K.

  16. SO<sub>2sub>-Resistant Immobilized Amine Sorbents for CO<sub>2sub> Capture

    SciTech Connect (OSTI)

    Tumuluri, Uma

    2014-01-01

    The solid amine sorbent for CO<sub>2sub> capture process has advantages of simplicity and low operating cost compared to the MEA (monoethanolamine) process. Solid amine sorbents reported so far suffered from either low CO<sub>2sub> capture capacity or low stability in the flue gas environment. This project is aimed at developing a SO<sub>2sub>-resistant solid amine sorbent for capturing CO<sub>2sub> from coalfired power plants with SCR/FGD which emits SO<sub>2sub>ranging from 15 to 30 ppm and NO ranging from 5 to 10 ppm. The amine sorbent we developed in a previous project degraded rapidly with 65% decrease in the initial capture capacity in presence of 1% SO<sub>2sub>. This amine sorbent was further modified by coating with polyethyleneglycol (PEG) to increase the SO<sub>2sub>-resistance. Polyethylene glycol (PEG) was found to decrease the SO<sub>2sub>-amine interaction, resulting in the decrease in the maximum SO desorption temperature (Tmax ) of amine sorbent. The PEG-coated amine sorbent exhibited higher stability with only 40% decrease in the initial capture capacity compared to un-coated amine sorbents. The cost of the solid amine sorbent developed in this project is estimated to be less than $7.00/lb; the sorbent exhibited CO<sub>2sub> capture capacity more than 2.3 mmol/g. The results of this study provided the scientific basis for further development of SO<sub>2sub>-resistant sorbents.

  17. Structural characterization and novel optical properties of defect chalcopyrite ZnGa{sub 2}Te{sub 4} thin films

    SciTech Connect (OSTI)

    Fouad, S.S.; Sakr, G.B.; Yahia, I.S.; Basset, D.M. Abdel

    2011-11-15

    Highlights: {yields} Preparation and characterization of ZnGa{sub 2}Te{sub 4} in powder and thin film forms. {yields} Structure properties such as XRD and EDX. {yields} Optical constant of the as-deposited ZnGa{sub 2}Te{sub 4} for the first time. {yields} Extraction of the optical parameters of the studied films. -- Abstract: Stoichiometric thin film samples of the ternary ZnGa{sub 2}Te{sub 4} defect chalcopyrite compound were prepared and characterized by X-ray diffraction technique. The elemental chemical composition of the prepared bulk material as well as of the as-deposited film was determined by energy-dispersive X-ray spectrometry. ZnGa{sub 2}Te{sub 4} thin films were deposited, by conventional thermal evaporation technique onto highly cleaned glass substrates. The X-ray and electron diffraction studies revealed that the as-deposited and the annealed ZnGa{sub 2}Te{sub 4} films at annealing temperature t{sub a} {<=} 548 K are amorphous, while those annealed at t{sub a} {>=} 573 K (for 1 h), are polycrystalline. The optical properties of the as-deposited films have been investigated for the first time at normal incidence in the spectral range from 500 to 2500 nm. The refractive index dispersion in the transmission and low absorption region is adequately described by the Wemple-DiDomenico single oscillator model, whereby, the values of the oscillator parameters have been calculated. The analysis of the optical absorption coefficient revealed an in-direct optical transition with energy of 1.33 eV for the as-deposited sample. This work suggested that ZnGa{sub 2}Te{sub 4} is a good candidate in solar cell devices as an absorbing layer.

  18. Influence of defects on the charge density wave of ([SnSe]<sub>1+?sub>)>1sub>(VSe>2sub>)>1sub> ferecrystals

    SciTech Connect (OSTI)

    Falmbigl, Matthias; Putzky, Daniel; Ditto, Jeffrey; Esters, Marco; Bauers, Sage R.; Ronning, Filip; Johnson, David C.

    2015-07-14

    A series of ferecrystalline compounds ([SnSe]<sub>1+?sub>)>1sub>(VSe>2sub>)>1sub> with varying Sn/V ratios were synthesized using the modulated elemental reactant technique. Temperature-dependent specific heat data reveal a phase transition at 102 K, where the heat capacity changes abruptly. An abrupt increase in electrical resistivity occurs at the same temperature, correlated with an abrupt increase in the Hall coefficient. Combined with the magnitude and nature of the specific heat discontinuity, this suggests that the transition is similar to the charge density wave transitions in transition metal dichalcogenides. An ordered intergrowth was formed over a surprisingly wide compositional range of Sn/V ratios of 0.89 ? 1 + ? ? 1.37. X-ray diffraction and transmission electron microscopy reveal the formation of various volume defects in the compounds in response to the nonstoichiometry. The electrical resistivity and Hall coefficient data of samples with different Sn/V ratios show systematic variation in the carrier concentration with the Sn/V ratio. There is no significant change in the onset temperature of the charge density wave transition, only a variation in the carrier densities before and after the transition. Given the sensitivity of the charge density wave transitions of transition metal dichalcogenides to variations in composition, it is very surprising that the charge density wave transition observed at 102 K for ([SnSe]<sub>1.15sub>)>1sub>(VSe>2sub>)>1sub> is barely influenced by the nonstoichiometry and structural defects. As a result, this might be a consequence of the two-dimensional nature of the structurally independent VSe<sub>2sub> layers.

  19. VO.sub.2 precipitates for self-protected optical surfaces

    DOE Patents [OSTI]

    Gea, Laurence A. (Knoxville, TN); Boatner, Lynn A. (Oak Ridge, TN)

    1999-01-01

    A method for forming crystallographically coherent precipitates of vanadium dioxide in the near-surface region of sapphire and the resulting product is disclosed. Ions of vanadium and oxygen are stoichiometrically implanted into a sapphire substrate (Al.sub.2 O.sub.3), and subsequently annealed to form vanadium dioxide precipitates in the substrate. The embedded VO.sub.2 precipitates, which are three-dimensionally oriented with respect to the crystal axes of the Al.sub.2 O.sub.3 host lattice, undergo a first-order monoclinic-to-tetragonal (and also semiconducting-to-metallic) phase transition at .about.77.degree. C. This transformation is accompanied by a significant variation in the optical transmission of the implanted region and results in the formation of an optically active, thermally "switchable" surface region on Al.sub.2 O.sub.3.

  20. VO{sub 2} precipitates for self-protected optical surfaces

    DOE Patents [OSTI]

    Gea, L.A.; Boatner, L.A.

    1999-03-23

    A method for forming crystallographically coherent precipitates of vanadium dioxide in the near-surface region of sapphire and the resulting product is disclosed. Ions of vanadium and oxygen are stoichiometrically implanted into a sapphire substrate (Al{sub 2}O{sub 3}), and subsequently annealed to form vanadium dioxide precipitates in the substrate. The embedded VO{sub 2} precipitates, which are three-dimensionally oriented with respect to the crystal axes of the Al{sub 2}O{sub 3} host lattice, undergo a first-order monoclinic-to-tetragonal (and also semiconducting-to-metallic) phase transition at ca. 77 C. This transformation is accompanied by a significant variation in the optical transmission of the implanted region and results in the formation of an optically active, thermally ``switchable`` surface region on Al{sub 2}O{sub 3}. 5 figs.

  1. Solvate Structures and Computational/Spectroscopic Characterization of LiBF<sub>4sub> Electrolytes

    SciTech Connect (OSTI)

    Seo, D. M.; Boyle, Paul D.; Allen, Joshua L.; Han, Sang D.; Jonsson, Erlendur; Johansson, Patrik; Henderson, Wesley A.

    2014-07-21

    Crystal structures have been determined for both LiBF<sub>4sub> and HBF<sub>4sub> solvates—(acetonitrile)<sub>2sub>:LiBF>4sub>, (ethylene glycol diethyl ether)<sub>1sub>:LiBF>4sub>, (diethylene glycol diethyl ether)1:LiBF<sub>4sub>, (tetrahydrofuran)<sub>1sub>:LiBF4, (methyl methoxyacetate)<sub>1sub>:LiBF>4sub>, (suc-cinonitrile)<sub>1sub>:LiBF>4sub>, (N,N,N',N",N"-pentamethyldiethylenetriamine)1:HBF<sub>4sub>, (N,N,N',N'-tetramethylethylenediamine)<sub>3/2sub>:HBF>4sub> and (phenanthroline)<sub>2sub>:HBF>4sub>. These, as well as other known LiBF<sub>4sub> solvate structures, have been characterized by Raman vibrational spectroscopy to unambiguously assign the anion Raman band positions to specific forms of BF<sub>4sub>-...Li+ cation coordination. In addition, complementary DFT calculations of BF<sub>4sub>-...Li+ cation complexes have provided additional insight into the challenges associated with accurately interpreting the anion interactions from experimental Raman spectra. This information provides a crucial tool for the characterization of the ionic association interactions within electrolytes.

  2. Structural distortions in the spin-gap regime of the quantum antiferromagnet SrCu{sub 2}(BO{sub 3}){sub 2}

    SciTech Connect (OSTI)

    Vecchini, C.; Adamopoulos, O.; Chapon, L.C.; Lappas, A.; Kageyama, H.; Ueda, Y.; Zorko, A.

    2009-12-15

    We report the first crystallographic study within the low-temperature (<40 K) spin-gap region of the two-dimensional frustrated antiferromagnet SrCu{sub 2}(BO{sub 3}){sub 2}. The crystal system does not deviate from the tetragonal I-42m space group symmetry. However, our high-resolution neutron powder diffraction measurements uncover subtle structural modifications below 34 K, concomitant to the formation of the dimer singlet ground state. Intimate spin-lattice coupling leads to negative thermal expansion of the tetragonal structure, which reflects into particular local lattice adjustments. The extracted structural parameters suggest the reduction of the buckling found in the copper-borate planes and the strengthening of the leading, in-plane intra-dimer superexchange interaction. The observed contraction along the c-axis, associated with the inter-dimer exchange in adjacent layers, indicates the involvement of weaker three-dimensional interactions in the magnetic properties. The rules posed by the crystal symmetry do not preclude Dzyaloshinsky-Moriya interactions, which therefore remain as an important source of spin anisotropy necessary to rationalise the ground state behaviour. - Abstract: We report the first crystallographic study within the low-temperature spin-gap region of the two-dimensional frustrated antiferromagnet SrCu{sub 2}(BO{sub 3}){sub 2}. Subtle spin-lattice coupling was unveiled in the low-temperature region. Display Omitted

  3. Epitaxial YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}/Sr{sub 2}RuO{sub 4} heterostructures

    SciTech Connect (OSTI)

    Schlom, D.G.; Merritt, B.A.; Madhavan, S. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering] [and others

    1997-09-01

    The anisotropic oxide superconductors YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} and Sr{sub 2}RuO{sub 4} have been epitaxially combined in various ways (c-axis on c-axis, c-axis on a-axis, and a-axis on a-axis) though the use of appropriate substrates. Phase-pure a-axis oriented or c-axis oriented epitaxial Sr{sub 2}RuO{sub 4} films were grown by pulsed laser deposition. YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films were then grown on both orientations of Sr{sub 2}RuO{sub 4} films and the resulting epitaxy was characterized.

  4. Electron density distribution in BaPb{sub 1-x}Sb{sub x}O{sub 3} superconducting oxides studied by double nuclear magnetic resonance methods

    SciTech Connect (OSTI)

    Piskunov, Yu. V. Ogloblichev, V. V.; Arapova, I. Yu.; Sadykov, A. V.; Gerashchenko, A. P.; Verkhovskii, S. V.

    2011-11-15

    The effect of charge disorder on the formation of an inhomogeneous state of the electron system in the conduction band in BaPb{sub 1-x}Sb{sub x}O{sub 3} superconducting oxides is investigated experimentally by NMR methods. The NMR spectra of {sup 17}O are measured systematically, and the contributions from {sup 17}O atoms with different cation nearest surroundings are identified. It is found that microscopic regions with an elevated spin density of charge carriers are formed within two coordination spheres near antimony ions. Nuclei of the superconducting phase of the oxide (regions with an elevated antimony concentration) microscopically distributed over the sample are detected in compounds with x = 0.25 and 0.33. Experiments in which a double resonance signal of the spin echo of {sup 17}O-{sup 207}Pb and {sup 17}O-{sup 121}Sb are measured in the metal phase of BaPb{sub 1-x}Sb{sub x}O{sub 3} oxides are carried out for the first time. The constants of indirect heteronuclear spin-spin {sup 17}O-{sup 207}Pb interaction are determined as functions of the local Knight shift {sub 207}Ks. The estimates of the constants of the indirect interaction between the nuclei of the nearest neighbors (O-Pb and Pb-Pb atoms) and analysis of evolution of the NMR spectra of {sup 17}O upon a change in the antimony concentration are convincing evidence in favor of the development of a microscopically inhomogeneous state of the electron system in the metal phase of BaPb{sub 1-x}Sb{sub x}O{sub 3} oxides.

  5. Structure and ferroelectric studies of (Ba{sub 0.85}Ca{sub 0.15})(Ti{sub 0.9}Zr{sub 0.1})O{sub 3} piezoelectric ceramics

    SciTech Connect (OSTI)

    Venkata Ramana, E.; Mahajan, A.; Graa, M.P.F.; Mendiratta, S.K.; Monteiro, J.M.; Valente, M.A.

    2013-10-15

    Graphical abstract: - Highlights: (Ba{sub 0.85}Ca{sub 0.15})(Ti{sub 0.9}Zr{sub 0.1})O{sub 3} (BCTZO) ceramic was synthesized by the ceramic method. In situ XRD and Raman spectra showed the phase transition of BCTZO around 360 K. The ceramics showed a tunability of 82% at 40 kV cm{sup ?1} electric field. BCTZO exhibited good quality factor of 111 at microwave frequencies. Piezoforce microscopy studies indicated the switchability of ferroelectric domains. - Abstract: We have synthesized and studied the structural and ferroelectric properties of lead-free 0.5(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3}0.5Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3} ceramics in the temperature region of its ferroelectric transition. The synthesized material showed high dielectric constant, low loss and good pyroelectric figure of merit. From the temperature dependent X-ray diffraction measurements, we determined the tricritical point to be in the temperature range of 303400 K. The dielectric measurements indicate a diffuse ferroelectric phase transition (DPT) around 360 K in agreement with the X-ray measurements. We studied the evolution of Raman spectra with temperature to understand the nature of phase transition in BaTiO{sub 3} (BTO) and the BCTZO. The results indicates that the transition of ferroelectricparaelectric state is not sharp as in the case of BTO and the polar state persists through the paraelectric state. In general, our study indicates that there are ferroelectric domains of nanometer size beyond the commonly defined transition temperature. The observation of local piezoelectric hysteresis loop indicated the existence of intrinsic ferroelectric property of the ceramic at the nanoscale. The ceramics exhibited electric field tunable dielectric properties with a tunability of 82% at an applied DC field of 40 kV cm{sup ?1}, low dielectric loss of 0.001 and room temperature pyroelectric coefficient of 6 10{sup ?8} C cm{sup ?2} K{sup ?1} and the detectivity of 1.9 10{sup ?8} C cm{sup ?1} J{sup ?1}; larger than those reported for other BaTiO{sub 3}-based materials. Overall, our results indicate that BCTZO ceramics with coexistence of rhombohedraltetragonal phases is a promising candidate for lead-free ferroelectric applications.

  6. Measurement of the ratio of the production cross sections times branching fractions of B<sub>c> ? J/??and B ? J/? K and B(B<sub>c>? J/? ???-/+)/B(B<sub>c> ? J/? ?) in pp collisions at ?s = 7 TeV

    SciTech Connect (OSTI)

    Khachatryan, V.

    2015-01-13

    The ratio of the production cross sections times branching fractions (?(B<sub>c>) B(B<sub>c> ? J/??))/(?(B) B(B ? J/?K) is studied in proton-proton collisions at a center-of-mass energy of 7 TeV with the CMS detector at the LHC. The kinematic region investigated requires Ba,sub>c> and Bmesons with transverse momentum p? > 15 GeV and rapidity |y| < 1.6. The data sample corresponds to an integrated luminosity of 5.1 fb-1. The ratio is determined to be [0.48 0.05 (stat) 0.03(syst) 0.05 (?B<sub>c>)]% The J/????-/+ decay mode is also observed in the same data sample. Using a model-independent method developed to measure the efficiency given the presence of resonant behaviour in the three-pion system, the ratio of the branching fractions J/? ???-/+)/B(B<sub>c> is measured to be 2.55 0.80(stat) 0.33(syst) +0.04<sub>-0.01sub> (?B<sub>c>), consistent with the previous LHCb result.

  7. Multiband Te p Based Superconductivity of Ta<sub>4sub>Pd>3sub>Te>16sub>

    SciTech Connect (OSTI)

    Singh, David J.

    2014-10-06

    We recently discovered that Ta<sub>4sub>Pd>3sub>Te>16 is a superconductor that has been suggested to be an unconventional superconductor near msub>agnetism. Here, we report electronic structure calculations showing that despite the layered crystal structure the material is an anisotropic three-dimensional (3D) metal. The Fermi surface contains prominent one-dimensional (1D) and two-dimensional (2D) features, including nested 1D sheets, a 2D cylindrical section, and a 3D sheet. Moreover, the electronic states that make up the Fermi surface are mostly derived from Te p states with small Ta d and Pd d contributions. This places the compound far from magnetic instabilities. The results are discussed in terms of multiband superconductivity.

  8. Negative to positive magnetoresistance and magnetocaloric effect in Pr<sub>0.6sub>Er>0.4sub>Al>2sub>

    SciTech Connect (OSTI)

    Pathak, Arjun K.; Gschneidner, Jr., K. A.; Pecharsky, V. K.

    2014-10-13

    We report on the magnetic, magnetocaloric and magnetotransport properties of Pr<sub>0.6sub>Er>0.4sub>Al>2sub>. The title compound exhibits a large positive magnetoresistance (MR) for H ≥ 40 kOe and a small but non negligible negative MR for H ≤ 30 kOe. The maximum positive MR reaches 13% at H = 80 kOe. The magnetic entropy and adiabatic temperature changes as functions of temperature each show two anomalies: a broad dome-like maximum below 20 K and a relatively sharp peak at higher temperature. As a result, observed behaviors are unique among other binary and mixed lanthanide compounds.

  9. Alternating magnetic anisotropy of Li<sub>2sub>(Li>1xsub>Tx>)N (T = Mn, Fe, Co, and Ni)

    SciTech Connect (OSTI)

    Jesche, A.; Ke, L.; Jacobs, J. L.; Harmon, B.; Houk, R. S.; Canfield, P. C.

    2015-05-11

    Substantial amounts of the transition metals Mn, Fe, Co, and Ni can be substituted for Li in single crystalline Li<sub>2sub>(Li>1xsub>Tx>)N. Isothermal and temperature-dependent magnetization measurements reveal local magnetic moments with magnitudes significantly exceeding the spin-only value. The additional contributions stem from unquenched orbital moments that lead to rare-earth-like behavior of the magnetic properties. Accordingly, extremely large magnetic anisotropies have been found. Most notably, the magnetic anisotropy alternates as easy plane?easy axis?easy plane?easy axis when progressing from T = Mn ? Fe ? Co ? Ni. This behavior can be understood based on a perturbation approach in an analytical, single-ion model. As a result, the calculated magnetic anisotropies show surprisingly good agreement with the experiment and capture the basic features observed for the different transition metals.

  10. Density functional theory calculations of magnetocrystalline anisotropy energies for (Fe<sub>1-xsub>Cox)>2sub>B

    SciTech Connect (OSTI)

    Daene, Markus; Kim, Soo Kyung; Surh, Michael P.; Aberg, Daniel; Benedict, Lorin X.

    2015-06-15

    We present and discuss density functional theory calculations of magnetic properties of the family of ferromagnetic compounds, (Fe<sub>1-xsub>Cox)>2sub>B, focusing specifically on the magnetocrystalline anisotropy energy (MAE). Using periodic supercells of various sizes (up to 96 atoms), it is shown that the general qualitative features of the composition dependence of the MAE is in agreement with experimental findings, while our predicted magnitudes are larger than those of experiment. We find that the use of small supercells (6 and 12-atom) favors larger MAE values relative to a statistical sample of configurations constructed with 96-atom supercells. As a result, the effect of lattice relaxations is shown to be small. Calculations of the Curie temperature for this alloy are also presented.

  11. Characterization of Cu(In,Ga)Se<sub>2sub> (CIGS) films with varying gallium ratios

    SciTech Connect (OSTI)

    Claypoole, Jesse; Peace, Bernadette; Sun, Neville; Dwyer, Dan; Eisaman, Matthew D.; Haldar, Pradeep; Efstathiadis, Harry

    2015-09-05

    Cu(In<sub>1-xsub>,Gax)Se>2sub> (CIGS) absorber layers were deposited on molybdenum (Mo) coated soda-lime glass substrates with varying Ga content (described as Ga/(In+Ga) ratios) with respect to depth. As the responsible mechanisms for the limitation of the performance of the CIGS solar cells with high Ga contents are not well understood, the goal of this work was to investigate different properties of CIGS absorber films with Ga/(In+Ga) ratios varied between 0.29 and 0.41 (as determined by X-ray florescence spectroscopy (XRF)) in order to better understand the role that the Ga content has on film quality. The Ga grading in the CIGS layer has the effect causing a higher bandgap toward the surface and Mo contact while the band gap in the middle of the CIGS layer is lower. Also, a wider and larger Ga/(In+Ga) grading dip located deeper in the CIGS absorber layers tend to produce larger grains in the regions of the films that have lower Ga/(In+Ga) ratios. It was found that surface roughness decreases from 51.2 nm to 41.0 nm with increasing Ga/(In+Ga) ratios. However, the surface roughness generally decreases if the Ga grading occurs deeper in the absorber layer.

  12. High temperature redox reactions with uranium: Synthesis and characterization of Cs(UO{sub 2})Cl(SeO{sub 3}), Rb{sub 2}(UO{sub 2}){sub 3}O{sub 2}(SeO{sub 3}){sub 2}, and RbNa{sub 5}U{sub 2}(SO{sub 4}){sub 7}

    SciTech Connect (OSTI)

    Babo, Jean-Marie; Albrecht-Schmitt, Thomas E.

    2013-10-15

    Cs(UO{sub 2})Cl(SeO{sub 3}) (1), Rb{sub 2}(UO{sub 2}){sub 3}O{sub 2}(SeO{sub 3}){sub 3} (2), and RbNa{sub 5}U{sub 2}(SO{sub 4}){sub 7} (3) single crystals were synthesized using CsCl, RbCl, and a CuCl/NaCl eutectic mixture as fluxes, respectively. Their lattice parameters and space groups are as follows: P2{sub 1}/n (a=6.548(1) Å, b=11.052(2) Å, c=10.666(2) Å and β=93.897(3)°), P1{sup ¯} (a=7.051(2) Å, b=7.198(2) Å, c=8.314(2) Å, α=107.897(3)°, β=102.687(3)° and γ=100.564(3)°) and C2/c (a=17.862(4) Å, b=6.931(1) Å, c=20.133(4) Å and β=109.737(6)°. The small anionic building units found in these compounds are SeO{sub 3}{sup 2−} and SO{sub 4}{sup 2−} tetrahedra, oxide, and chloride. The crystal structure of the first compound is composed of [(UO{sub 2}){sub 2}Cl{sub 2}(SeO{sub 3}){sub 2}]{sup 2−} chains separated by Cs{sup +} cations. The structure of (2) is constructed from [(UO{sub 2}){sub 3}O{sub 11}]{sup 16−} chains further connected through selenite units into layers stacked perpendicularly to the [0 1 0] direction, with Rb{sup +} cations intercalating between them. The structure of compound (3) is made of uranyl sulfate layers formed by edge and vertex connections between dimeric [U{sub 2}O{sub 16}] and [SO{sub 4}] polyhedra. These layers contain unusual sulfate–metal connectivity as well as large voids. - Graphical abstract: A new family of uranyl selenites and sulfates has been prepared by high-temperature redox reactions. This compounds display new bonding motifs. Display Omitted - Highlights: • Low-dimensional Uranyl Oxoanion compounds. • Conversion of U(IV) to U(VI) at high temperatures. • Dimensional reduction by both halides and stereochemically active lone-pairs.

  13. Complex conductance of ultrathin La<sub>2-xsub>SrxCuO>4sub> films and heterostructures

    SciTech Connect (OSTI)

    V. A. Gasparov; Bozovic, I.

    2015-10-23

    We used atomic-layer molecular beam epitaxy to synthesize bilayers of a cuprate metal (La<sub>1.55sub>Sr>0.45sub>CuO>4sub>) and a cuprate insulator (La<sub>2sub>CuO>4sub>), in which each layer is just one unit cells thick. We have studied the magnetic field and temperature dependence of the complex sheet conductance, σ(ω), of these films. Experiments have been carried out at frequencies between 2 and 50 MHz using the single-spiral coil technique. We found that: (i) the inductive response starts at ΔT = 3 K lower temperatures than Re σ(T), which in turn is characterized by a peak close to the transition, (ii) this shift is almost constant with magnetic field up to 14 mT; (iii) ΔT increases sharply up to 4 K at larger fields and becomes constant up to 8 T; (iv) the vortexdiffusion constant D(T) is not linear with T at low temperatures as in the case of free vortices, but is rather exponential due to pinning of vortex cores, and (v) the dynamic Berezinski–Kosterlitz–Thouless (BKT) transition temperature occurs at the point where Y=(l<sub>ω>/ξ+)2 = 1. As a result, our experimental results can be described well by the extended dynamic theory of the BKT transition and dynamics of bound vortex–antivortex pairs with short separation lengths.

  14. Anionic ordering and thermal properties of FeF<sub>3sub>·3H<sub>2sub>O

    SciTech Connect (OSTI)

    Burbano, Mario; Duttine, Mathieu; Borkiewicz, Olaf; Wattiaux, Alain; Demourgues, Alain; Salanne, Mathieu; Groult, Henri; Dambournet, Damien

    2015-09-17

    In this study, iron fluoride tri-hydrate can be used to prepare iron hydroxyfluoride with the Hexagonal-Tungsten-Bronze (HTB) type structure, a potential cathode material for batteries. To understand this phase transformation, a structural description of β-FeF<sub>3sub>·3H<sub>2sub>O is first performed by means of DFT calculations and Mössbauer spectroscopy. The structure of this compound consists of infinite chains of [FeF<sub>6sub>]n and [FeF<sub>2sub>(H2O)<sub>4sub>]n>. The decomposition of FeF<sub>3sub>·3H<sub>2sub>O induces a collapse and condensation of these chains, which lead to the stabilization, under specific conditions, of a hydroxyfluoride network FeF<sub>3-xsub>(OH)x> with the HTB structure. The release of H<sub>2sub>O and HF was monitored by thermal analysis and physical characterizations during the decomposition of FeF<sub>3sub>·3H<sub>2sub>O. An average distribution of FeF<sub>4sub>(OH)>2sub> distorted octahedra in HTB-FeF<sub>3-xsub>(OH)x> was obtained subsequent to the thermal hydrolysis/olation of equatorial anionic positions involving F- and H<sub>2sub>O. This study provides a clear understanding of the structure and thermal properties of FeF<sub>3sub>·3H<sub>2sub>O, a material that can potentially bridge the recycling of pickling sludge from the steel industry by preparing battery electrodes.

  15. Neutron-scattering evidence for a periodically modulated superconducting phase in the underdoped cuprate La<sub>1.905sub>Ba>0.095sub>CuO>4sub>

    SciTech Connect (OSTI)

    Xu, Zhijun; Stock, C.; Chi, Songxue; Kolesnikov, A. I.; Xu, Guangyong I.; Gu, Genda; Tranquada, J. M.

    2014-10-01

    The role of antiferromagnetic spin correlations in high-temperature superconductors remains a matter of debate. We present inelastic neutron-scattering evidence that gapless spin fluctuations coexist with superconductivity in La<sub>1.905sub>Ba>0.095sub>CuO>4sub>. Furthermore, we observe that both the low-energy magnetic spectral weight and the spin incommensurability are enhanced with the onset of superconducting correlations. We propose that the coexistence occurs through intertwining of spatial modulations of the pair wave function and the antiferromagnetic correlations. This proposal is also directly relevant to sufficiently underdoped La<sub>2-xsub>SrxCuO>4sub> and YBa<sub>2sub>Cu>3sub>O>6+xsub>.

  16. Case Studies of the ROZ CO<sub>2sub> Flood and the Combined ROZ/MPZ CO<sub>2sub> Flood at the Goldsmith Landreth Unit, Ector County, Texas. Using ''Next Generation'' CO<sub>2sub> EOR Technologies to Optimize the Residual Oil Zone CO<sub>2sub> Flood

    SciTech Connect (OSTI)

    Trentham, Robert C.; Melzer, L. Stephen; Kuuskraa, Vello; Koperna, George

    2015-06-30

    The technology for CO<sub>2sub> Enhanced Oil Recovery (CO<sub>2sub> EOR) has significantly advanced since the earliest floods were implemented in the 1970s. At least for the Permian Basin region of the U.S., the oil recovery has been now been extended into residual oil zones (ROZs) where the mobile fluid phase is water and immobile phase is oil. But the nature of the formation and fluids within the ROZs has brought some challenges that were not present when flooding the MPZs. The Goldsmith-Landreth project in the Permian Basin was intended to first identify the most pressing issues of the ROZs floods and, secondly, begin to address them with new techniques designed to optimize a flood that commingled the MPZ and the ROZ. The early phase of the research conducted considerable reservoir and fluid characterization work and identified both technical and commercial challenges of producing the enormous quantities of water when flooding the ROZs. It also noted the differing water compositions in the ROZ as compared to the overlying MPZs. A new CO<sub>2sub> gas lift system using a capillary string was successfully applied during the project which conveyed the CO<sub>2sub> to the deeper and differing ROZ reservoir conditions at Goldsmith and added a second capillary string that facilitated applying scale inhibitors to mitigate the scaling tendencies of the mixing ROZ and MPZ formation waters. The project also undertook a reservoir modeling effort, using the acquired reservoir characterization data, to history match both the primary and water flood phases of the MPZ and to establish the initial conditions for a modeling effort to forecast response of the ROZ to CO<sub>2sub> EOR. With the advantage of many profile logs acquired from the operator, some concentration on the original pattern area for the ROZ pilot was accomplished to attempt to perfect the history match for that area. Several optional scenarios for producing the ROZ were simulated seeking to find the preferred mode of producing the two intervals. Finally, the project attempted to document for the first time the production performance of commingled MPZ and ROZ CO<sub>2sub> EOR project at the nearby Seminole San Andres Unit. The analysis shows that over 10,000 bopd can be shown to be coming from the ROZ interval, a zone that would have produced no oil under primary or water flood phases. A similar analysis was done for the GLSAU project illustrating that 2000 bopd of incremental EOR oil is currently being produced. The results of the modeling work would suggest that 800 bopd can be attributed to the ROZ alone at GLSAU.

  17. Covariance mapping of two-photon double core hole states in C <sub>2sub> H <sub>2sub> and C <sub>2sub> H <sub>6sub> produced by an x-ray free electron laser

    SciTech Connect (OSTI)

    Mucke, M; Zhaunerchyk, V; Frasinski, L J; Squibb, R J; Siano, M; Eland, J H D; Linusson, P; Salén, P; Meulen, P v d; Thomas, R D; Larsson, M; Foucar, L; Ullrich, J; Motomura, K; Mondal, S; Ueda, K; Osipov, T; Fang, L; Murphy, B F; Berrah, N; Bostedt, C; Bozek, J D; Schorb, S; Messerschmidt, M; Glownia, J M; Cryan, J P; Coffee, R N; Takahashi, O; Wada, S; Piancastelli, M N; Richter, R; Prince, K C; Feifel, R

    2015-07-01

    Few-photon ionization and relaxation processes in acetylene (C<sub>2sub>H>2sub>) and ethane (C<sub>2sub>H>6sub>) were investigated at the linac coherent light source x-ray free electron laser (FEL) at SLAC, Stanford using a highly efficient multi-particle correlation spectroscopy technique based on a magnetic bottle. The analysis method of covariance mapping has been applied and enhanced, allowing us to identify electron pairs associated with double core hole (DCH) production and competing multiple ionization processes including Auger decay sequences. The experimental technique and the analysis procedure are discussed in the light of earlier investigations of DCH studies carried out at the same FEL and at third generation synchrotron radiation sources. In particular, we demonstrate the capability of the covariance mapping technique to disentangle the formation of molecular DCH states which is barely feasible with conventional electron spectroscopy methods.

  18. Jumpstarting commercial-scale CO<sub>2sub> capture and storage with ethylene production and enhanced oil recovery in the US Gulf

    SciTech Connect (OSTI)

    Middleton, Richard S.; Levine, Jonathan S.; Bielicki, Jeffrey M.; Viswanathan, Hari S.; Carey, J. William; Stauffer, Philip H.

    2015-04-27

    CO<sub>2sub> capture, utilization, and storage (CCUS) technology has yet to be widely deployed at a commercial scale despite multiple high-profile demonstration projects. We suggest that developing a large-scale, visible, and financially viable CCUS network could potentially overcome many barriers to deployment and jumpstart commercial-scale CCUS. To date, substantial effort has focused on technology development to reduce the costs of CO<sub>2sub> capture from coal-fired power plants. Here, we propose that near-term investment could focus on implementing CO<sub>2sub> capture on facilities that produce high-value chemicals/products. These facilities can absorb the expected impact of the marginal increase in the cost of production on the price of their product, due to the addition of CO<sub>2sub> capture, more than coal-fired power plants. A financially viable demonstration of a large-scale CCUS network requires offsetting the costs of CO<sub>2sub> capture by using the CO<sub>2sub> as an input to the production of market-viable products. As a result, we demonstrate this alternative development path with the example of an integrated CCUS system where CO<sub>2sub> is captured from ethylene producers and used for enhanced oil recovery in the U.S. Gulf Coast region.

  19. Luminescence of Ce 3+ -Doped MB<sub>2sub>Si>2sub>O>8sub> (M = Sr, Ba): A Deeper Insight into the Effects of Electronic Structure and Stokes Shift

    SciTech Connect (OSTI)

    Peng, Qi; Liu, Chunmeng; Hou, Dejian; Zhou, Weijie; Ma, Chong-Geng; Liu, Guokui; Brik, Mikhail G.; Tao, Ye; Liang, Hongbin

    2015-12-18

    A series of Sr <sub>1 -2x sub>Ce<sub>xNaxB>2sub>Si>2sub>O>8sub> and Ba <sub>1-2x sub>Ce<sub>xKxB>2sub>Si>2sub>O>8sub> (x = 0.005, 0.01, 0.02, 0.04, 0.06, 0.08) samples were synthesized by a high-temperature solid-state reaction. The low temperature excitation, emission, and fluorescence decay spectra together demonstrated that all spectral bands arise from the Ce 3+ ions located at only one kind of lattice site. The first-principles calculations of the structural and electronic properties of pure and Ce 3+sub>2sub>Si>2sub>O>8sub> (M = Sr, Ba) were performed, and the obtained results were used for understanding the structural changes after doping and identification of the observed position of the host absorption bands. The measured 4f-5d excitation and emission spectra of Ce3+ ions doped in MB<sub>2sub>Si>2sub>O>8sub> were analyzed and simulated in the framework of the crystal-field (CF) theory. The electron-phonon coupling effect generally ignored in most studies published so far was also taken into account by applying the configurational coordinate model. The validity of such a combined insight into the 5d CF energy level positions and the Stokes shift has been confirmed by analyzing the dependence of the Ce 3+

  20. Reverse Monte Carlo simulation of Se{sub 80}Te{sub 20} and Se{sub 80}Te{sub 15}Sb{sub 5} glasses

    SciTech Connect (OSTI)

    Abdel-Baset, A. M.; Rashad, M.; Moharram, A. H.

    2013-12-16

    Two-dimensional Monte Carlo of the total pair distribution functions g(r) is determined for Se{sub 80}Te{sub 20} and Se{sub 80}Te{sub 15}Sb{sub 5} alloys, and then it used to assemble the three-dimensional atomic configurations using the reverse Monte Carlo simulation. The partial pair distribution functions g{sub ij}(r) indicate that the basic structure unit in the Se{sub 80}Te{sub 15}Sb{sub 5} glass is di-antimony tri-selenide units connected together through Se-Se and Se-Te chain. The structure of Se{sub 80}Te{sub 20} alloys is a chain of Se-Te and Se-Se in addition to some rings of Se atoms.

  1. Evolution of electronic states in the Kondo alloy system Yb{sub 1{minus}x}Lu{sub x}B{sub 12}

    SciTech Connect (OSTI)

    Susaki, T.; Konishi, T.; Sekiyama, A.; Mizokawa, T.; Fujimori, A.; Iwasaki, T.; Ueda, S.; Matsushita, T.; Suga, S.; Ishii, H.; Iga, F.; Kasaya, M.

    1997-12-01

    We have studied the effect of Lu substitution on the Kondo insulator YbB{sub 12} by high-resolution photoemission. Comparison of the spectra of YbB{sub 12}, Yb{sub 0.5}Lu{sub 0.5}B{sub 12}, and LuB{sub 12} reveals that the density of states (DOS) of the B sp-derived conduction band near the Fermi level is reduced in YbB{sub 12} over a rather wide ({approximately} 40 meV) energy region. Lu substitution (i) recovers the reduced B sp DOS, (ii) shifts the Yb 4f-derived Kondo peak towards higher binding energy, and (iii) decreases the Yb valence. These results are consistently analyzed using the Anderson-impurity model, and imply interaction between the Yb 4f ions mediated by the Yb 4f-B sp hybridization in YbB{sub 12}. {copyright} {ital 1997} {ital The American Physical Society}

  2. Effect of calcination temperature on electrical properties of Nd{sub 0.7}Ba{sub 0.3}MnO{sub 3}

    SciTech Connect (OSTI)

    Lim, K. P.; Halim, S. A.; Chen, S. K.; Ng, S. W.; Chew, Z. Y.

    2015-04-24

    In this work, Nd{sub 0.7}Ba{sub 0.3}MnO{sub 3} was synthesized via cryo-milling method to investigate the effect of calcination temperature on the structure, microstructure, magnetic and electrical properties. XRD analysis revealed all samples can be indexed to orthorhombic structure systems with Imma space group accompany with some minor phases of Mn{sub 2}O{sub 4} and BaMnO{sub 3}. FESEM analysis confirmed that a slight increase in the grain size from 117.4 nm (600C), 119.5 nm (700C), 121.0 nm (800C), 123.1 nm (900C) to 138.4 nm (1000C) was observed when different calcination temperature was applied. Four Point Probe measurements showed that all samples are in paramagnetic insulating region and T{sub MIT} is lower than 20K. Resistivity increase when grain size reduces due to increase of effective grain boundary that weakens the electron hopping process via double exchange mechanism. Beside, a drastic increase of resistivity also observed due to present of minor secondary phase (BaMnO{sub 3}) in sample C9.

  3. Lasing characteristics of ZrO{sub 2}Y{sub 2}O{sub 3}Ho{sub 2}O{sub 3} crystal

    SciTech Connect (OSTI)

    Borik, M A; Lomonova, E E; Kulebyakin, A V; Ushakov, S N; Lyapin, A A; Ryabochkina, P A; Chabushkin, A N

    2013-09-30

    The spectral dependences of the gain cross section of the {sup 5}I{sub 8} ? {sup 5}I{sub 7}, {sup 5}I{sub 7} ? {sup 5}I{sub 8} transition of Ho{sup 3+} ions in the ZrO{sub 2} 13.6 mol % Y{sub 2}O{sub 3} 0.4 mol % Ho{sub 2}O{sub 3} crystal are calculated at different relative population inversions using the absorption and luminescence spectra of the {sup 5}I{sub 8} ? {sup 5}I{sub 7} and {sup 5}I{sub 7} ? {sup 5}I{sub 8} transitions of Ho{sup 3+} ions at T=''300'' K. Lasing of these crystals at the {sup 5}I{sub 7} ? {sup 5}I{sub 8} transition is obtained for the first time under pumping by a Tm : YLiF{sub 4} laser (?{sub p} = 1.905 ?m). The lasing wavelength is 2.17 ?m. (lasers)

  4. Effects of coexisting spin disorder and antiferromagnetism on the magnetic behavior of nanostructured (Fe{sub 79}Mn{sub 21}){sub 1−x}Cu{sub x} alloys

    SciTech Connect (OSTI)

    Mizrahi, M. E-mail: cabrera@fisica.unlp.edu.ar; Cabrera, A. F. E-mail: cabrera@fisica.unlp.edu.ar; Desimoni, J.; Stewart, S. J.

    2014-06-07

    We report a magnetic study on nanostructured (Fe{sub 79}Mn{sub 21}){sub 1−x}Cu{sub x} (0.00 ≤ x ≤ 0.30) alloys using static magnetic measurements. The alloys are mainly composed by an antiferromagnetic fcc phase and a disordered region that displays a spin-glass-like behavior. The interplay between the antiferromagnetic and magnetically disordered phases establishes an exchange anisotropy that gives rise to a loop shift at temperatures below the freezing temperature of moments belonging to the disordered region. The loop shift is more noticeable as the Cu content increases, which also enhances the spin-glass-like features. Further, in the x = 0.30 alloy the alignment imposed by applied magnetic fields higher than 4 kOe prevail over the configuration determined by the frustration mechanism that characterizes the spin glass-like phase.

  5. Linear and nonlinear optical properties of GaAs/Al{sub x}Ga{sub 1?x}As/GaAs/Al{sub y}Ga{sub 1?y}As multi-shell spherical quantum dot

    SciTech Connect (OSTI)

    Emre Kavruk, Ahmet E-mail: aekavruk@gmail.com; Koc, Fatih; Sahin, Mehmet E-mail: mehsahin@gmail.com

    2013-11-14

    In this work, the optical properties of GaAs/Al{sub x}Ga{sub 1?x}As/GaAs/Al{sub y}Ga{sub 1?y}As multi-shell quantum dot heterostructure have been studied as a function of Al doping concentrations for cases with and without a hydrogenic donor atom. It has been observed that the absorption coefficient strength and/or resonant absorption wavelength can be adjusted by changing the Al content of inner-barrier and/or outer-barrier regions. Besides, it has been shown that the donor atom has an important effect on the control of the electronic and optical properties of the structure. The results have been presented as a function of the Al contents of the inner-barrier x and outer-barrier y regions and probable physical reasons have been discussed.

  6. Synthesis of g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction with enhanced photocatalytic performance

    SciTech Connect (OSTI)

    He, Peizhi; Song, Limin; Zhang, Shujuan; Wu, Xiaoqing; Wei, Qingwu

    2014-03-01

    Graphical abstract: g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction photocatalyst with visible-light response was prepared by a facile coprecipitation method. The results show that g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} possesses a much higher activity for the decomposition of RhB than that of the pure Ag{sub 3}PO{sub 4} particles. The most mechanism is that g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction photocatalyst can efficiently separate the photogenerated electronhole pairs, enhancing the photocatalytic activity of g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} composites. - Highlights: g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction showed much higher activity than that of Ag{sub 3}PO{sub 4}. The high activity could be attributed to g-C{sub 3}N{sub 4} for modifying Ag{sub 3}PO{sub 4}. More OH radicals may be significant reason to improve Ag{sub 3}PO{sub 4} activity. - Abstract: g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction photocatalyst with visible-light response was prepared by a facile coprecipitation method. The photocatalysts were characterized by X-ray powder diffraction, transmission electron microscopy, UVvis absorption spectroscopy and Fourier transform infrared spectroscopy. The photocatalytic activities of the obtained samples were tested by using Rhodamine B (RhB) as the degradation target under visible light irradiation. g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} decomposed RhB more effectively than the pure Ag{sub 3}PO{sub 4} particles did, and 2 wt.% g-C{sub 3}N{sub 4} had the highest activity. Furthermore, 2 wt.% g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} degraded high-concentration RhB more potently than unmodified Ag{sub 3}PO{sub 4} did, probably because g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction photocatalyst enhanced the photocatalytic activity by efficiently separating the photogenerated electronhole pairs.

  7. Dopant spin states and magnetism of Sn{sub 1?x}Fe{sub x}O{sub 2} nanoparticles

    SciTech Connect (OSTI)

    Punnoose, A. Dodge, Kelsey; Reddy, K. M.; Franco, Nevil; Chess, Jordan; Eixenberger, Josh; Beltrn, J. J.; Barrero, C. A.

    2014-05-07

    This work reports detailed investigations of a series of ?2.6?nm sized, Sn{sub 1?x}Fe{sub x}O{sub 2} crystallites with x?=?00.10 using Mossbauer spectroscopy, x-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance spectroscopy (EPR), and magnetometry to determine the oxidation state of Fe dopants and their role in the observed magnetic properties. The magnetic moment per Fe ion ? was the largest ?6.48??10{sup ?3} ?{sub B} for the sample with the lowest (0.001%) Fe doping, and it showed a rapid downward trend with increasing Fe doping. Majority of the Fe ions are in 3+ oxidation state occupying octahedral sites. Another significant fraction of Fe dopant ions is in 4+ oxidation state and a still smaller fraction might be existing as Fe{sup 2+} ions, both occupying distorted sites, presumably in the surface regions of the nanocrystals, near oxygen vacancies. These studies also suggest that the observed magnetism is not due to exchange coupling between Fe{sup 3+} spins. A more probable role for the multi-valent Fe ions may be to act as charge reservoirs, leading to charge transfer ferromagnetism.

  8. [Ni(H{sub 2}O){sub 4}]{sub 3}[U(OH,H{sub 2}O)(UO{sub 2}){sub 8}O{sub 12}(OH){sub 3}], crystal structure and comparison with uranium minerals with U{sub 3}O{sub 8}-type sheets

    SciTech Connect (OSTI)

    Rivenet, Murielle; Vigier, Nicolas; Roussel, Pascal; Abraham, Francis

    2009-04-15

    The new U(VI) compound, [Ni(H{sub 2}O){sub 4}]{sub 3}[U(OH,H{sub 2}O)(UO{sub 2}){sub 8}O{sub 12}(OH){sub 3}], was synthesized by mild hydrothermal reaction of uranyl and nickel nitrates. The crystal-structure was solved in the P-1 space group, a=8.627(2), b=10.566(2), c=12.091(4) A and alpha=110.59(1), beta=102.96(2), gamma=105.50(1){sup o}, R=0.0539 and wR=0.0464 from 3441 unique observed reflections and 151 parameters. The structure of the title compound is built from sheets of uranium polyhedra closely related to that in beta-U{sub 3}O{sub 8}. Within the sheets [(UO{sub 2})(OH)O{sub 4}] pentagonal bipyramids share equatorial edges to form chains, which are cross-linked by [(UO{sub 2})O{sub 4}] and [UO{sub 4}(H{sub 2}O)(OH)] square bipyramids and through hydroxyl groups shared between [(UO{sub 2})(OH)O{sub 4}] pentagonal bipyramids. The sheets are pillared by sharing the apical oxygen atoms of the [(UO{sub 2})(OH)O{sub 4}] pentagonal bipyramids with the oxygen atoms of [NiO{sub 2}(H{sub 2}O){sub 4}] octahedral units. That builds a three-dimensional framework with water molecules pointing towards the channels. On heating [Ni(H{sub 2}O){sub 4}]{sub 3}[U(OH,H{sub 2}O)(UO{sub 2}){sub 8}O{sub 12}(OH){sub 3}] decomposes into NiU{sub 3}O{sub 10}. - Graphical abstract: The framework of [Ni(H{sub 2}O){sub 4}]{sub 3}[U(OH,H{sub 2}O)(UO{sub 2}){sub 8}O{sub 12}(OH){sub 3}] built from uranium polyhedra sheets pillared by Ni-centered octahedra.

  9. Study of the microstructure of plasma sprayed coatings obtained from Al{sub 2}O{sub 3}13TiO{sub 2} nanostructured and conventional powders

    SciTech Connect (OSTI)

    Gral, A.; ?rawski, W.; Lity?ska-Dobrzy?ska, L.

    2014-10-15

    The microstructure of coatings obtained from nanostructured or conventional Al{sub 2}O{sub 3}13TiO{sub 2} powders and deposited by plasma spraying technique on low-carbon steel was examined by transmission electron microscopy techniques. The dominating phase in both coatings was ?-Al{sub 2}O{sub 3} phase. It has been observed that the grains of ?-Al{sub 2}O{sub 3} grew in various shapes and sizes, that are particularly visible in the case of coating sprayed from nanostructured powder. The coatings obtained from the fully melted conventional powders exhibited a typical lamellar microstructure, into which the strips of TiO{sub 2} phase were extended. The microstructure of coatings produced from agglomerates of nanostructured particles also revealed the regions consisting of partially melted ?-Al{sub 2}O{sub 3} powders surrounded by the net-like structure formed from fully melted oxides that improved the coating properties. Along with the observed morphology diversity some changes in the chemical composition on the cross sections of obtained coatings have been also noticed. - Highlights: Plasma sprayed Al{sub 2}O{sub 3}13TiO{sub 2} coatings reveal diversity of microstructure. Microstructure of conventional coating was formed from fully melted crushed powders. Nanostructured coating contains completely and partially melted initial agglomerates.

  10. Magnetism and superconductivity in U?Pt<sub>xRh>(1x)sub>C?

    SciTech Connect (OSTI)

    Wakeham, N.; Ni, Ni; Bauer, E. D.; Thompson, J. D.; Tegtmeier, E.; Ronning, F.

    2015-01-01

    We report the phase diagram of the doping series U?Pt<sub>xRh>(1x)sub>C?, studied through measurements of resistivity, specific heat, and magnetic susceptibility. The Nel temperature of U?Rh?C? of ~ 22 K is suppressed with increasing Pt content, reaching zero temperature close to x = 0.7, where we observed signatures of increased quantum fluctuations. In addition, evidence is presented that the antiferromagnetic state undergoes a spin-reorientation transition upon application of an applied magnetic field. This transition shows non-monotonic behavior as a function of x, peaking at around x = 0.3. Superconductivity is observed for x ? 0.9, with T<sub>c> increasing with increasing x. The reduction in T<sub>c> and increase in residual resistivity with decreasing Pt content is inconsistent with the extension of the Abrikosov-Gor'kov theory to unconventional superconductivity.

  11. Criticality Safety Study of UF<sub>6sub>and UO<sub>2sub>F>2sub>in 8-in. Inner Diameter Piping

    SciTech Connect (OSTI)

    Elam, K.R.

    2003-10-07

    The purpose of this report is to provide an evaluation of the criticality safety aspects of using up to 8-in.-inner-diameter (ID) piping as part of a system to monitor the {sup 235}U enrichment in uranium hexafluoride (UF{sub 6}) gas both before and after an enrichment down-blending operation. The evaluated operation does not include the blending stage but includes only the monitors and the piping directly associated with the monitors, which are in a separate room from the blending operation. There are active controls in place to limit the enrichment of the blended UF{sub 6} to a maximum of 5 weight percent (wt%) {sup 235}U. Under normal operating conditions of temperature and pressure, the UF{sub 6} will stay in the gas phase and criticality will not be credible. The two accidents of concern are solidification of the UF{sub 6} along with some hydrofluoric acid (HF) and water or moisture ingress, which would cause the UF{sub 6} gas to react and form a hydrated uranyl fluoride (UO{sub 2}F{sub 2}) solid or solution. Of these two types of accidents, the addition of water and formation of UO{sub 2}F{sub 2} is the most reactive scenario and thus limits related to UO{sub 2}F{sub 2} will bound the limits related to UF{sub 6}. Two types of systems are included in the monitoring process. The first measures the enrichment of the approximately 90 wt% enriched UF{sub 6} before it is blended. This system uses a maximum 4-in.-(10.16-cm-) ID pipe, which is smaller than the 13.7-cm-cylinder-diameter subcritical limit for UO{sub 2}F{sub 2} solution of any enrichment as given in Table 1 of American National Standard ANSI/ANS-8.1.1 Therefore, this system poses no criticality concerns for either accident scenario. The second type of system includes two enrichment monitors for lower-enriched UF{sub 6}. One monitors the approximately 1.5 wt% enriched UF{sub 6} entering the blending process, and the second monitors the approximately 5 wt% enriched UF{sub 6} coming out of the blending process. Both use a maximum 8-in.-(20.32-cm-) ID piping, where the length of the larger ID piping is approximately 9.5 m. This diameter of piping is below the 26.6-cm-cylinder-diameter subcritical limit for 5 wt% enriched UO{sub 2}F{sub 2} solutions as given in Table 6 of ANSI/ANS-8.1. Therefore, for up to 5 wt% enriched UF{sub 6}, this piping does not present a criticality concern for either accident scenario. Calculations were performed to determine the enrichment level at which criticality could become a concern in these 8-in.-ID piping sections. Both unreflected and fully water-reflected conditions were considered.

  12. Properties of Si{sub n}, Ge{sub n}, and Si{sub n}Ge{sub n} clusters

    SciTech Connect (OSTI)

    Dong, Yi; Rehman, Habib ur; Springborg, Michael

    2015-01-22

    The structures of Si{sub n}, Ge{sub n}, and Si{sub n}Ge{sub n} clusters with up to 44 atoms have been determined theoretically using an unbiased structure-optimization method in combination with a parametrized, density-functional description of the total energy for a given structure. By analyzing the total energy in detail, particularly stable clusters are identified. Moreover, general trends in the structures are identified with the help of specifically constructed descriptors.

  13. Intrinsic relationship between electronic structures and phase transition of SrBi{sub 2?x}Nd{sub x}Nb{sub 2}O{sub 9} ceramics from ultraviolet ellipsometry at elevated temperatures

    SciTech Connect (OSTI)

    Duan, Z. H.; Jiang, K.; Xu, L. P.; Li, Y. W.; Hu, Z. G. Chu, J. H.

    2014-02-07

    The ferroelectric orthorhombic to paraelectric tetragonal phase transition of SrBi{sub 2?x}Nd{sub x}Nb{sub 2}O{sub 9} (x?=?0, 0.05, 0.1, and 0.2) layer-structured ceramics has been investigated by temperature-dependent spectroscopic ellipsometry. Based on the analysis of dielectric functions from 0 to 500?C with double Tauc-Lorentz dispersion model, the interband transitions located at ultraviolet region have shown an abrupt variation near the Curie temperature. The changes of dielectric functions are mainly due to the thermal-optical and/or photoelastic effect. Moreover, the characteristic alteration in interband transitions can be ascribed to distortion of NbO{sub 6} octahedron and variation of hybridization between Bi 6s and O 2p states during the structure transformation.

  14. Correlating Local Structure with Electrochemical Activity in L<sub>i2sub>MnO>3sub>

    SciTech Connect (OSTI)

    Nanda, Jagjit; Sacci, Robert L.; Veith, Gabriel M.; Dixit, Hemant M.; Cooper, Valentino R.; Pezeshki, Alan M.; Ruther, Rose E.

    2015-07-31

    Li<sub>2sub>MnO>3sub> is of interest as one component of the composite lithium-rich oxides, which are under development for high capacity, high voltage cathodes in lithium ion batteries. Despite such practical importance, the mechanism of electrochemical activity in Li<sub>2sub>MnO>3sub> is contested in the literature, as are the effects of long-term electrochemical cycling. Here, Raman spectroscopy and mapping are used to follow the chemical and structural changes that occur in Li<sub>2sub>MnO>3sub>. Both conventional slurry electrodes and thin films are studied as a function of the state of charge (voltage) and cycle number. Thin films have similar electrochemical properties as electrodes prepared from slurries, but allow for spectroscopic investigations on uniform samples without carbon additives. Spectral changes correlate well with electrochemical activity and support a mechanism whereby capacity is lost upon extended cycling due to the formation of new manganese oxide phases. Raman mapping of both thin film and slurry electrodes charged to different voltages reveals significant variation in the local structure. Poor conductivity and slow kinetics associated with a two-phase reaction mechanism contribute to the heterogeneity.

  15. Initial results from seismic monitoring at the Aquistore CO<sub>2sub> storage site, Saskatchewan, Canada

    SciTech Connect (OSTI)

    White, D. J.; Roach, L. A.N.; Roberts, B.; Daley, T. M.

    2014-12-31

    The Aquistore Project, located near Estevan, Saskatchewan, is one of the first integrated commercial-scale CO<sub>2sub> storage projects in the world that is designed to demonstrate CO<sub>2sub> storage in a deep saline aquifer. Starting in 2014, CO<sub>2sub> captured from the nearby Boundary Dam coal-fired power plant will be transported via pipeline to the storage site and to nearby oil fields for enhanced oil recovery. At the Aquistore site, the CO<sub>2sub> will be injected into a brine-filled sandstone formation at ~3200 m depth using the deepest well in Saskatchewan. The suitability of the geological formations that will host the injected CO<sub>2sub> has been predetermined through 3D characterization using high-resolution 3D seismic images and deep well information. These data show that 1) there are no significant faults in the immediate area of the storage site, 2) the regional sealing formation is continuous in the area, and 3) the reservoir is not adversely affected by knolls on the surface of the underlying Precambrian basement. Furthermore, the Aquistore site is located within an intracratonic region characterized by extremely low levels of seismicity. This is in spite of oil-field related water injection in the nearby Weyburn-Midale field where a total of 656 million m3 of water have been injected since the 1960`s with no demonstrable related induced seismicity. A key element of the Aquistore research program is the further development of methods to monitor the security and subsurface distribution of the injected CO<sub>2sub>. Toward this end, a permanent areal seismic monitoring array was deployed in 2012, comprising 630 vertical-component geophones installed at 20 m depth on a 2.5x2.5 km regular grid. This permanent array is designed to provide improved 3D time-lapse seismic imaging for monitoring subsurface CO<sub>2sub>. Prior to the onset of CO<sub>2sub> injection, calibration 3D surveys were acquired in May and November of 2013. Comparison of the data from these surveys relative to the baseline 3D survey data from 2012 shows excellent repeatability (NRMS less than 10%) which will provide enhanced monitoring sensitivity to smaller amounts of CO<sub>2sub>. The permanent array also provides continuous passive monitoring for injection-related microseismicity. Passive monitoring has been ongoing since the summer of 2012 in order to establish levels of background seismicity before CO<sub>2sub> injection starts in 2014. Microseismic monitoring was augmented in 2013 by the installation of 3 broadband seismograph stations surrounding the Aquistore site. These surface installations should provide a detection capability of seismic events with magnitudes as low as ~0. Downhole seismic methods are also being utilized for CO<sub>2sub> monitoring at the Aquistore site. Baseline crosswell tomographic images depict details (meters-scale) of the reservoir in the 150-m interval between the observation and injection wells. This level of resolution is designed to track the CO<sub>2sub> migration between the wells during the initial injection period. A baseline 3D vertical seismic profile (VSP) was acquired in the fall of 2013 to provide seismic images with resolution on a scale between that provided by the surface seismic array and the downhole tomography. The 3D VSP was recorded simultaneously using both a conventional array of downhole geophones (60-levels) and an optical fibre system. The latter utilized an optical fiber cable deployed on the outside of the monitor well casing and cemented in place. A direct comparison of these two methodologies will determine the suitability of using the fiber cable for ongoing time-lapse VSP monitoring.

  16. Synthesis, crystal structure and thermal behavior of two hydrated forms of lanthanide phthalates Ln{sub 2}(O{sub 2}+C{sub 6}H{sub 4}-CO{sub 2}){sub 3}(H{sub 2}O) (Ln=Ce, Nd) and Nd{sub 2}(O{sub 2}C-C{sub 6}H{sub 4}-CO{sub 2}){sub 3}(H{sub 2}O){sub 3}

    SciTech Connect (OSTI)

    Pizon, David; Henry, Natacha; Loiseau, Thierry; Roussel, Pascal; Abraham, Francis

    2010-09-15

    New hydrated lanthanide phthalates have been hydrothermally prepared with cerium and neodymium in different reaction media involving water or mixed water-ethanol solvent. The monohydrated Ln{sub 2}(1,2-bdc){sub 3}(H{sub 2}O) (Ln=Ce or Nd) and dihydrated Nd{sub 2}(1,2-bdc){sub 3}(H{sub 2}O){sub 2} forms have been characterized by single-crystal analysis. Their structures consist of infinite inorganic chains of lanthanide-centered polyhedra linked to each other through the phthalate ligands in order to generate mixed organic-inorganic layered structure. The two hydrated structures differ by the number of terminal water species attached to the lanthanide cations, which induce symmetry change from a triclinic (Nd{sub 2}(1,2-bdc){sub 3}(H{sub 2}O){sub 2}) to an orthorhombic (Nd{sub 2}(1,2-bdc){sub 3}(H{sub 2}O){sub 2}) cell for neodymium whereas the cerium-based phase only exists in the monohydrated form, with two distinct symmetries (orthorhombic or triclinic). Structural comparisons with the other members of the lanthanide phthalate series with identical chemical formula are also discussed. Thermal X-ray diffraction experiment indicates that the transformation from dihydrate form into the monohydrated form does not occur during a heating process. - Graphical abstract: New members of the chain-like structures of neodymium phthalates with different hydration states Nd{sub 2}(1,2-bdc){sub 3}(H{sub 2}O){sub x} (x=1 or 2, 1-2bdc=phthalate group) and comparison with cerium-based analogs.

  17. Oxygen trapped by rare earth tetrahedral clusters in Nd<sub>4sub>FeOS>6sub>: Crystal structure, electronic structure, and magnetic properties

    SciTech Connect (OSTI)

    Lin, Qisheng; Taufour, Valentin; Zhang, Yuemei; Wood, Max; Drtina, Thomas; Bud’ko, Sergey L.; Canfield, Paul C.; Miller, Gordon J.

    2015-05-22

    Single crystals of Nd<sub>4sub>FeOS>6sub> were grown from an Fe-S eutectic solution. Single crystal X-ray diffraction analysis revealed a Nd<sub>4sub>MnOSe>6sub>-type structure (P6<sub>3sub>mc, a = 9.2693(1) Å, c = 6.6650(1) Å, V = 495.94(1) Å3, Z = 2), featuring parallel chains of face-sharing [FeS<sub>6x1/2sub>]4- trigonal antiprisms and interlinked [Nd<sub>4sub>OS>3sub>]4+ cubane-like clusters. Oxygen atoms were found to be trapped by Nd4 clusters in the [Nd4OS3]4+ chains. Structural differences among Nd<sub>4sub>MnOSe>6sub>-type Nd<sub>4sub>FeOS>6sub> and the related La<sub>3sub>CuSiS>7sub>- and Pr<sub>8sub>CoGa>3sub>-type structures have been described. Magnetic susceptibility measurements on Nd<sub>4sub>FeOS>6sub> suggested the dominance of antiferromagnetic interactions at low temperature, but no magnetic ordering down to 2 K was observed. Spin-polarized electronic structure calculations revealed magnetic frustration with dominant antiferromagnetic interactions.

  18. Structureproperty relations of orthorhombic [(CH{sub 3}){sub 3}NCH{sub 2}COO]{sub 2}(CuCl{sub 2}){sub 3}2H{sub 2}O

    SciTech Connect (OSTI)

    Hausshl, Eiken; Schreuer, Jrgen; Wiehl, Leonore; Paulsen, Natalia

    2014-04-01

    Large single crystals of orthorhombic [(CH{sub 3}){sub 3}NCH{sub 2}COO]{sub 2}(CuCl{sub 2}){sub 3}2H{sub 2}O with dimensions up to 404030 mm{sup 3} were grown from aqueous solutions. The elastic and piezoelastic coefficients were derived from ultrasonic resonance frequencies and their shifts upon variation of pressure, respectively, using the plate-resonance technique. Additionally, the coefficients of thermal expansion were determined between 95 K and 305 K by dilatometry. The elastic behaviour at ambient conditions is dominated by the 2-dimensional network of strong hydrogen bonds within the (001) plane leading to a corresponding pseudo-tetragonal anisotropy of the longitudinal elastic stiffness. The variation of elastic properties with pressure, however, as well as the thermal expansion shows strong deviations from the pseudo-tetragonal symmetry. These deviations are probably correlated with tilts of the elongated tri-nuclear betaineCuCl{sub 2}water complexes. Neither the thermal expansion nor the specific heat capacity gives any hint on a phase transition in the investigated temperature range. - Graphical abstract: Single crystal of orthorhombic [(CH{sub 3}){sub 3}NCH{sub 2}COO]{sub 2}(CuCl{sub 2}){sub 3}2H{sub 2}O. - Highlights: Large single crystals (40 40 30 mm{sup 3}) of [(CH{sub 3}){sub 3}NCH{sub 2}COO]{sub 2}(CuCl{sub 2}){sub 3}2H{sub 2}O were grown. The elastic and piezoelastic coefficients were derived from ultrasonic resonance frequencies. Thermal expansion (95 K305 K) and heat capacity (113 K323 K) were determined. The orthorhombic structure shows pseudo-tetragonal elastic anisotropy at ambient conditions. The crystal structure is stable in the investigated range (11600 bar, 95303 K)

  19. Regional Carbon Sequestration Partnerships Initiatives review meeting. Proceedings

    SciTech Connect (OSTI)

    2006-07-01

    A total of 32 papers were presented at the review meeting in sessions entitled: updates on regional characterization activities; CO{sub 2} sequestration with EOR; CO{sub 2} sequestration in saline formations I and II; and terrestrial carbon sequestration field projects. In addition are five introductory papers. These are all available on the website in slide/overview/viewgraph form.

  20. Bio-corrosion and cytotoxicity studies on novel Zr<sub>55sub>Co>30sub>Ti>15sub> and Cu<sub>60sub>Zr>20sub>Ti>20sub> metallic glasses

    SciTech Connect (OSTI)

    Vincent, S.; Daiwile, A.; Devi, S. S.; Kramer, M. J.; Besser, M. F.; Murty, B. S.; Bhatt, Jatin

    2014-09-26

    Metallic glasses are a potential and compatible implant candidate for biomedical applications. In the present investigation, a comparative study between novel Zr<sub>55sub>Co>30sub>Ti>15sub> and Cu<sub>60sub>Zr>20sub>Ti>20sub> metallic glasses is carried out to evaluate in vitro biocompatibility using simulated body fluids. The bio-corrosion behavior of Zr- and Cu-based metallic glasses in different types of artificial body fluids such as artificial saliva solution, phosphate-buffered saline solution, artificial blood plasma solution, and Hanks balanced saline solution is evaluated using potentiodynamic polarization studies at a constant body temperature of 310.15 K (37 C). Surface morphology of samples after bio-corrosion experiments was observed by scanning electron microscopy. In vitro cytotoxicity test on glassy alloys were performed using human osteosarcoma cell line as per 10993-5 guidelines from International Organization for Standardization. As a result, the comparative study between Zr- and Cu-based glassy alloys provides vital information about the effect of elemental composition on biocompatibility of metallic glasses.

  1. Interfacial charge-mediated non-volatile magnetoelectric coupling in Co<sub>0.3sub>Fe>0.7sub>/Ba>0.6sub>Sr>0.4sub>TiO>3sub>/Nb:SrTiO>3sub> multiferroic heterostructures

    SciTech Connect (OSTI)

    Zhou, Ziyao; Howe, Brandon M.; Liu, Ming; Nan, Tianxiang; Chen, Xing; Mahalingam, Krishnamurthy; Sun, Nian X.; Brown, Gail J.

    2015-01-13

    The central challenge in realizing non-volatile, E-field manipulation of magnetism lies in finding an energy efficient means to switch between the distinct magnetic states in a stable and reversible manner. In this work, we demonstrate using electrical polarization-induced charge screening to change the ground state of magnetic ordering in order to non-volatilely tune magnetic properties in ultra-thin Co<sub>0.3sub>Fe>0.7sub>/Ba>0.6sub>Sr>0.4sub>TiO>3sub>/Nb:SrTiO>3sub> (001) multiferroic heterostructures. A robust, voltage-induced, non-volatile manipulation of out-of-plane magnetic anisotropy up to 40 Oe is demonstrated and confirmed by ferromagnetic resonance measurements. This discovery provides a framework for realizing charge-sensitive order parameter tuning in ultra-thin multiferroic heterostructures, demonstrating great potential for delivering compact, lightweight, reconfigurable, and energy-efficient electronic devices.

  2. Dimethyl sulfide substituted mixed-metal clusters: Synthesis, structure, and characterization of HRuCo sub 3 (CO) sub 11 (SMe sub 2 ) and (HRuRh sub 3 (CO) sub 9 ) sub 2 (SMe sub 2 ) sub 3

    SciTech Connect (OSTI)

    Rossi, S.; Pursianinen, J.; Ahlgren, M.; Pakkanen, T.A. (Univ. of Joensuu (Finland))

    1990-02-01

    Ligand substitution reactions of dimethyl sulfide with mixed-metal clusters are described. The clusters HRuCo{sub 3}(CO){sub 11}(SMe{sub 2}) (1) and (HRuRh{sub 3}(CO){sub 9}){sub 2}(SMe{sub 2}){sub 3} (2) have been prepared by reactions of SMe{sub 2} with the neutral parent clusters. Their crystal structures have been established: 1, monoclinic, space group P2{sub 1}/n, a = 11.459 (5) {angstrom}, b = 12.484 (4) {angstrom}, c = 14.384 (4) {angstrom}, {beta} = 96.40 (3){degree}, Z = 4; 2, trigonal, space group R3c, a = 13.181 (7) {angstrom}, {alpha} = 75.54 (5){degree}, Z = 2. Dimethyl sulfide coordinates terminally as a two-electron donor on basal cobalt in 1 and as a bridging four-electron donor causing unusual dimerization of clusters in 2. The carbonyl arrangement of the parent clusters was not changed during the ligand substitution, and hydride ligands bridge the three basal metals in both compounds.

  3. Quantum critical fluctuations in the heavy fermion compound Ce(Ni<sub>0.935sub> Pd<sub>0.065sub>)>2sub>Ge>2sub>

    SciTech Connect (OSTI)

    Wang, C. H.; Poudel, L.; Taylor, A. E.; Lawrence, J. M.; Christianson, A. D.; Chang, S.; Rodriguez-Rivera, J. A.; Lynn, J. W.; Podlesnyak, A. A.; Ehlers, G.; Baumbach, R. E.; Bauer, E. D.; Gofryk, K.; Ronning, F.; McClellan, K. J.; Thompson, J. D.

    2015-01-14

    Electric resistivity, specific heat, magnetic susceptibility, and inelastic neutron scattering experi- ments were performed on a single crystal of the heavy fermion compound Ce(Ni<sub>0.935sub> Pd<sub>0.065sub>)>2sub>Ge>2sub> in order to study the spin fluctuations near an antiferromagnetic (AF) quantum critical point (QCP). The resistivity and the specific heat coefficient for T ≤ 1 K exhibit the power law behavior expected for a 3D itinerant AF QCP (ρ(T) ~ T3/2 and γ(T) ~ γ<sub>0sub> - bT1/2). However, for 2 ≤ T ≤ 10 K, the susceptibility and specific heat vary as log T and the resistivity varies linearly with temperature. Furthermore, despite the fact that the resistivity and specific heat exhibit the non-Fermi liquid behavior expected at a QCP, the correlation length, correlation time, and staggered susceptibility of the spin fluctuations remain finite at low temperature. We suggest that these deviations from the divergent behavior expected for a QCP may result from alloy disorder.

  4. Fundamental Understanding of Methane-Carbon Dioxide-Water (CH<sub>4sub>-CO>2sub>-H>2sub>O) Interactions in Shale Nanopores under Reservoir Conditions. Quarterly Report.

    SciTech Connect (OSTI)

    Wang, Yifeng

    2015-10-27

    This project focuses on the systematic study of CH<sub>4sub>-CO>2sub>-H>2sub>O interactions in shale nanopores under high-pressure and high temperature reservoir conditions. The proposed work will help to develop new stimulation strategies to enable efficient resource recovery from fewer and less environmentally impactful wells.

  5. Observation of giant exchange bias in bulk Mn{sub 50}Ni{sub 42}Sn{sub 8} Heusler alloy

    SciTech Connect (OSTI)

    Sharma, Jyoti; Suresh, K. G.

    2015-02-16

    We report a giant exchange bias (EB) field of 3520?Oe in bulk Mn{sub 50}Ni{sub 42}Sn{sub 8} Heusler alloy. The low temperature magnetic state of the martensite phase has been studied by DC magnetization and AC susceptibility measurements. Frequency dependence of spin freezing temperature (T{sub f}) on critical slowing down relation and observation of memory effect in zero field cooling mode confirms the super spin glass (SSG) phase at low temperatures. Large EB is attributed to the strong exchange coupling between the SSG clusters formed by small regions of ferromagnetic order embedded in an antiferromagnetic (AFM) matrix. The temperature and cooling field dependence of EB have been studied and related to the change in unidirectional anisotropy at SSG/AFM interface. The training effect also corroborates with the presence of frozen (SSG) moments at the interface and their role in EB.

  6. Li<sub>2sub>S encapsulated by nitrogen-doped carbon for lithium sulfur batteries

    SciTech Connect (OSTI)

    Chen, Lin; Liu, Yuzi; Ashuri, Maziar; Liu, Caihong; Shaw, Leon L.

    2014-09-26

    Using high-energy ball milling of the Li<sub>2sub>S plus carbon black mixture followed by carbonization of pyrrole, we have established a facile approach to synthesize Li<sub>2sub>S-plus-C composite particles of average size 400 nm, encapsulated by a nitrogen-doped carbon shell. Such an engineered core–shell structure exhibits an ultrahigh initial discharge specific capacity (1029 mAh/g), reaching 88% of the theoretical capacity (1,166 mAh/g of Li<sub>2sub>S) and thus offering the highest utilization of Li<sub>2sub>S in the cathode among all of the reported works for the encapsulated Li<sub>2sub>S cathodes. This Li<sub>2sub>S/C composite core with a nitrogen-doped carbon shell can still retain 652 mAh/g after prolonged 100 cycles. These superior properties are attributed to the nitrogen-doped carbon shell that can improve the conductivity to enhance the utilization of Li<sub>2sub>S in the cathode. As a result, fine particle sizes and the presence of carbon black within the Li<sub>2sub>S core may also play a role in high utilization of Li<sub>2sub>S in the cathode.

  7. Characterization of photoluminescent (Y{sub 1{minus}x}Eu{sub x}){sub 2}O{sub 3} thin-films prepared by metallorganic chemical vapor deposition

    SciTech Connect (OSTI)

    McKittrick, J.; Bacalski, C.F.; Hirata, G.A.; Hubbard, K.M.; Pattillo, S.G.; Salazar, K.V.; Trkula, M.

    1998-12-01

    Europium doped yttrium oxide, (Y{sub 1{minus}x}Eu{sub x}){sub 2}O{sub 3}, thin-films were deposited on silicon and sapphire substrates by metallorganic chemical vapor deposition (MOCVD). The films were grown in a MOCVD chamber reacting yttrium and europium tris(2,2,6,6-tetramethyl-3,5,-heptanedionates) precursors in an oxygen atmosphere at low pressures (5 Torr) and low substrate temperatures (500--700 C). The films deposited at 500 C were flat and composed of nanocrystalline regions of cubic Y{sub 2}O{sub 3}, grown in a textured [100] or [110] orientation to the substrate surface. Films deposited at 600 C developed from the flat, nanocrystalline morphology into a plate-like growth morphology oriented in the [111] with increasing deposition time. Monoclinic Y{sub 2}O{sub 3}:Eu{sup 3+} was observed in x-ray diffraction for deposition temperatures {ge}600 C on both (111) Si and (001) sapphire substrates. This was also confirmed by the photoluminescent emission spectra.

  8. Optimizing white light luminescence in Dy{sup 3+}-doped Lu{sub 3}Ga{sub 5}O{sub 12} nano-garnets

    SciTech Connect (OSTI)

    Haritha, P.; Linganna, K.; Venkatramu, V.; Martn, I. R.; Monteseguro, V.; Rodrguez-Mendoza, U. R.; Babu, P.; Len-Luis, S. F.; Jayasankar, C. K.; Lavn, V.

    2014-11-07

    Trivalent dysprosium-doped Lu{sub 3}Ga{sub 5}O{sub 12} nano-garnets have been prepared by sol-gel method and characterized by X-ray powder diffraction, high-resolution transmission electron microscopy, dynamic light scattering, and laser excited spectroscopy. Under a cw 457?nm laser excitation, the white luminescence properties of Lu{sub 3}Ga{sub 5}O{sub 12} nano-garnets have been studied as a function of the optically active Dy{sup 3+} ion concentration and at low temperature. Decay curves for the {sup 4}F{sub 9/2} level of Dy{sup 3+} ion exhibit non-exponential nature for all the Dy{sup 3+} concentrations, which have been well-fitted to a generalized energy transfer model for a quadrupole-quadrupole interaction between Dy{sup 3+} ions without diffusion. From these data, a simple rate-equations model can be applied to predict that intense white luminescence could be obtained from 1.8?mol% Dy{sup 3+} ions-doped nano-garnets, which is in good agreement with experimental results. Chromaticity color coordinates and correlated color temperatures have been determined as a function of temperature and are found to be within the white light region for all Dy{sup 3+} concentrations. These results indicate that 2.0?mol% Dy{sup 3+} ions doped nano-garnet could be useful for white light emitting device applications.

  9. A Rh<sub>xSy>/C Catalyst for the Hydrogen Oxidation and Hydrogen Evolution Reactions in HBr

    SciTech Connect (OSTI)

    Masud, Jahangir; Nguyena, Trung V.; Singh, Nirala; McFarland, Eric; Ikenberry, Myles; Hohn, Keith; Pan, Chun-Jern; Hwang, Bing-Joe

    2015-01-01

    Rhodium sulfide (Rh<sub>2sub>S>3sub>) on carbon support was synthesized by refluxing rhodium chloride with ammonium thiosulfate. Thermal treatment of Rh<sub>2sub>S>3sub> at high temperatures (600C to 850C) in presence of argon resulted in the transformation of Rh<sub>2sub>S>3sub> into Rh<sub>3sub>S>4sub>, Rh<sub>17sub>S>15sub> and Rh which were characterized by TGA/DTA, XRD, EDX, and deconvolved XPS analyses. The catalyst particle size distribution ranged from 3 to 12 nm. Cyclic voltammetry and rotating disk electrode measurements were used to evaluate the catalytic activity for hydrogen oxidation and evolution reactions in H<sub>2sub>SO>4sub> and HBr solutions. The thermally treated catalysts show high activity for the hydrogen reactions. The exchange current densities (i<sub>o>) of the synthesized Rh<sub>xSy> catalysts in H<sub>2sub>-saturated 1M H<sub>2sub>SO>4sub> and 1M HBr for HER and HOR were 0.9 mA/cm2 to 1.0 mA/cm2 and 0.8 to 0.9 mA/cm2, respectively. The lower i<sub>o> values obtained in 1M HBr solution compared to in H<sub>2sub>SO>4sub> might be due to the adsorption of Br- on the active surface. Stable electrochemical active surface area (ECSA) of Rh<sub>xSy> catalyst was obtained for CV scan limits between 0 V and 0.65 V vs. RHE. Scans with upper voltage limit beyond 0.65 V led to decreased and unreproducible ECSA measurements.

  10. Microsoft PowerPoint - SS2_8H_NERC_SANS_Final.ppt

    Energy Savers [EERE]

    SS-2 SANS SCADA Summit September 28,29, 2006 Intermediate SCADA Security 2 SANS SCADA Security Summit II September 28, 29, 2006 Disclaimer References made herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the U.S. Government, any agency thereof, or any company affiliated with the Idaho National Laboratory. Use the described security tools

  11. Transfer between the cesium 6 {sup 2}P{sub 1/2} and 6 {sup 2}P{sub 3/2} levels induced by collisions with H{sub 2}, HD, D{sub 2}, CH{sub 4}, C{sub 2}H{sub 6}, CF{sub 4}, and C{sub 2}F{sub 6}

    SciTech Connect (OSTI)

    Pitz, Greg A.; Fox, Charles D.; Perram, Glen P.

    2011-09-15

    The cross sections of spin-orbit energy exchange between the cesium 6 {sup 2}P{sub 1/2}{r_reversible}6 {sup 2}P{sub 3/2} states induced by collisions with N{sub 2}, H{sub 2}, HD, D{sub 2}, CH{sub 4}, C{sub 2}H{sub 6}, CF{sub 4}, and C{sub 2}F{sub 6} were obtained for pressures less than 100 Torr at room temperature by means of steady-state laser-induced fluorescence techniques. The spin-orbit energy exchange rate with N{sub 2}, H{sub 2}, HD, D{sub 2}, CH{sub 4}, C{sub 2}H{sub 6}, CF{sub 4}, and C{sub 2}F{sub 6}, have been measured as {sigma}{sub 21}(6 {sup 2}P{sub 3/2}{yields}6 {sup 2}P{sub 1/2})= 16.3, 34.1, 30.0, 22.7, 21.4, 65.6, 64.8, and 137 A{sup 2} and {sigma}{sub 12}(6 {sup 2}P{sub 1/2}{yields}6 {sup 2}P{sub 3/2})= 1.8, 4.4, 4.1, 3.0, 2.9, 13.3, 9.7, and 16.3 A{sup 2}, respectively. Correlations of the spin-orbit transfer probabilities with rotational-energy defect and vibrational-energy defect have been shown.

  12. Reversible Exsolution of Nanometric Fe<sub>2sub>O>3 sub> Particles in BaFe<sub>2-xsub>(PO>4sub>)>2sub> (0 ? x ? 2/3):The Logic of Vacancy Ordering in Novel Metal-Depleted Two-Dimensional Lattices

    SciTech Connect (OSTI)

    Alcover, Ignacio Blazquez; David, Rnald; Daviero-Minaud, Sylvie; Filimonov, Dmitry; Huv, Marielle; Roussel, Pascal; Kabbour, Houria; Mentr, Olivier

    2015-08-12

    We show here that the exsolution of Fe2+ ions out of two-dimensional (2D) honeycomb layers of BaFe<sub>2sub>(PO>4sub>)>2 sub>into iron-deficient BaFe<sub>2xsub>(PO>4sub>)>2sub> phases and nanometric ?-Fe<sub>2sub>O>3sub> (typically 50 nm diameter at the grain surface) is efficient and reversible until x = 2/3 in mild oxidizing/reducing conditions. It corresponds to the renewable conversion of 12 wt % of the initial mass into iron oxide. After analyzing single crystal X-ray diffraction data of intermediate members x = 2/7, x = 1/3, x = 1/2 and the ultimate Fe-depleted x = 2/3 term, we then observed a systematic full ordering between Fe ions and vacancies (V<sub>Fe>) that denote unprecedented easy in-plane metal diffusion driven by the Fe2+/Fe3+ redox. Besides the discovery of a diversity of original depleted triangular <sub>?>{Fe2/3+<sub>2xsub>O>6sub>} topologies, we propose a unified model correlating the x Fe-removal and the experimental Fe/V<sub>Fe> ordering into periodic one-dimensional motifs paving the layers, gaining insights into predictive crystahemistry of complex low dimensional oxides. When we increased the x values it led to a progressive change of the materials from 2D ferromagnets (Fe2+) to 2D ferrimagnets (Fe2/3+) to antiferromagnets for x = 2/3 (Fe3+).

  13. Insulating and metallic spin glass in K<sub>xFe>2-?-ysub>NiySe>2sub> (0.06 ? y ? 1.44 ) single crystals

    SciTech Connect (OSTI)

    Ryu, Hyejin; Abeykoon, Milinda; Wang, Kefeng; Lei, Hechang; Lazarevic, N.; Warren, J. B.; Bozin, E. S.; Popovic, Z. V.; Petrovic, C.

    2015-05-04

    We report electron doping effects by Ni in K<sub>xFe>2-?-ysub>Niy>Se? (0.06 ? y ? 1.44) single crystal alloys. A rich ground state phase diagram is observed. Thus, a small amount of Ni (~ 4%) suppressed superconductivity below 1.8 K, inducing insulating spin glass magnetic ground state for higher Ni content. With further Ni substitution, metallic resistivity is restored. For high Ni concentration in the lattice the unit cell symmetry is high symmetry I4/mmm with no phase separation whereas both I4/m + I4/mmm space groups were detected in the phase separated crystals when concentration of Ni < Fe. The absence of superconductivity coincides with the absence of crystalline Fe vacancy order.

  14. Synthesis and crystal structure of the palladium oxides NaPd{sub 3}O{sub 4}, Na{sub 2}PdO{sub 3} and K{sub 3}Pd{sub 2}O{sub 4}

    SciTech Connect (OSTI)

    Panin, Rodion V. Khasanova, Nellie R.; Abakumov, Artem M.; Antipov, Evgeny V.; Tendeloo, Gustaaf van; Schnelle, Walter

    2007-05-15

    NaPd{sub 3}O{sub 4}, Na{sub 2}PdO{sub 3} and K{sub 3}Pd{sub 2}O{sub 4} have been prepared by solid-state reaction of Na{sub 2}O{sub 2} or KO{sub 2} and PdO in sealed silica tubes. Crystal structures of the synthesized phases were refined by the Rietveld method from X-ray powder diffraction data. NaPd{sub 3}O{sub 4} (space group Pm3-barn, a=5.64979(6) A, Z=2) is isostructural to NaPt{sub 3}O{sub 4}. It consists of NaO{sub 8} cubes and PdO{sub 4} squares, corner linked into a three-dimensional framework where the planes of neighboring PdO{sub 4} squares are perpendicular to each other. Na{sub 2}PdO{sub 3} (space group C2/c, a=5.3857(1) A, b=9.3297(1) A, c=10.8136(2) A, {beta}=99.437(2){sup o}, Z=8) belongs to the Li{sub 2}RuO{sub 3}-structure type, being the layered variant of the NaCl structure, where the layers of octahedral interstices filled with Na{sup +} and Pd{sup 4+} cations alternate with Na{sub 3} layers along the c-axis. Na{sub 2}PdO{sub 3} exhibits a stacking disorder, detected by electron diffraction and Rietveld refinement. K{sub 3}Pd{sub 2}O{sub 4}, prepared for the first time, crystallizes in the orthorhombic space group Cmcm (a=6.1751(6) A, b=9.1772(12) A, c=11.3402(12) A, Z=4). Its structure is composed of planar PdO{sub 4} units connected via common edges to form parallel staggered PdO{sub 2} strips, where potassium atoms are located between them. Magnetic susceptibility measurements of K{sub 3}Pd{sub 2}O{sub 4} reveal a Curie-Weiss behavior in the temperature range above 80 K. - Graphical abstract: Na{sub 2}PdO{sub 3} (space group C2/c, a=5.3857(1) A, b=9.3297(1) A, c=10.8136(2) A, {beta}=99.437(2), Z=8) belongs to the Li{sub 2}RuO{sub 3}-structure type, being the layered variant of the NaCl structure, where the layers of octahedral interstices filled with Na{sup +} and Pd{sup 4+} cations (NaPd{sub 2}O{sub 6} slabs) alternate with Na{sub 3} layers along the c-axis.

  15. Structural relationships between new carbide La{sub 14}Sn(MnC{sub 6}){sub 3} and fully ordered La{sub 11}(MnC{sub 6}){sub 3}

    SciTech Connect (OSTI)

    Zaikina, Julia V.; Zhou, Haidong; Latturner, Susan E.

    2010-12-15

    Crystals of the ternary La{sub 11}(MnC{sub 6}){sub 3} and new quaternary carbide La{sub 14}Sn(MnC{sub 6}){sub 3} phases were grown from La/Ni eutectic flux and their structures were determined by means of X-ray single crystal diffraction. La{sub 11}(MnC{sub 6}){sub 3} is a new superstructure variant of La{sub 3.67}MnC{sub 6} (previously reported disordered subcell: P6{sub 3}/m; a{sub 0}=8.806 A; c{sub 0}=5.329 A, Z=2). The superstructure (R3-bar ; a={radical}3a{sub 0}=15.2649(9) A; c=3c{sub 0}=16.013(1) A, Z=6; R{sub 1}=0.022) is realized by complete ordering of the La chains within the columns of face-sharing carbon octahedra, with alternating La-La distances leading to R-centering and enlargement of the unit cell. The structure of the quaternary carbide La{sub 14}Sn(MnC{sub 6}){sub 3} (P6-bar ; a=8.756(1) A; c=10.483(2) A, Z=1; R{sub 1}=0.026) is closely related to that of La{sub 11}(MnC{sub 6}){sub 3} with part of the MnC{sub 6} units replaced by Sn atoms. The structure and precise composition of La{sub 14}Sn(MnC{sub 6}){sub 3} can be derived from that of La{sub 11}(MnC{sub 6}){sub 3} by taking into account the extent of this substitution and variation in lanthanum siting in the chain of carbon octahedra. Band structure calculations indicate both phases are metallic; the La{sub 11}(MnC{sub 6}){sub 3} phase is stabilized by the ordering of La atoms which induces a pseudogap at E{sub F}. -- La{sub 11}(MnC{sub 6}){sub 3} with fully ordered superstructure and a new carbide La{sub 14}Sn(MnC{sub 6}){sub 3} were obtained from La/Ni eutectic flux. Display Omitted

  16. Magnetic order in RBa/sub 2/Cu/sub 2/O/sub 6+//sub x/ (invited)

    SciTech Connect (OSTI)

    Lynn, J.W.; Li, W.

    1988-11-15

    Neutron scattering results on the RBa/sub 2/ Cu/sub 3/ O/sub 6+//sub x/ (R = rare earth) class of systems are reviewed. For the oxygen-deficient systems (x<0.5), which are semiconducting, the Cu ions are observed to order with Neel temperatures as high as 500 K. The magnetic structure consists of strong nearest-neighbor antiferromagnetic couplings of the Cu spins within the Cu-O/sub 2/ layers, while nearest-neighbor spins in adjacent layers are also aligned antiferromagnetically. The moments are constrained in the tetragonal plane. At lower temperatures the Cu moments in the oxygen-deficient ''chain'' layers also order antiferromagnetically, with a moment that can be quite substantial (approx. 1/2 ..mu../sub B/). Both transition temperatures are very sensitive to the oxygen concentration. The magnetic heavy rare-earth compounds, on the other hand, order antiferromagnetically at very low temperatures, analogous to the ''conventional'' magnetic-superconductor systems such as RMo/sub 6/ S/sub 8/ and RRh/sub 4/ B/sub 4/. The ordering is not very sensitive to the oxygen concentration, and the antiferromagnetic state coexists with superconductivity. Differences in the ordering behavior are ascribed to crystal-field effects, which are briefly discussed. Finally, small-angle neutron scattering results in the vicinity of the superconducting transition temperature are also discussed.

  17. Facile synthesis of Ba<sub>1-xsub>Kx>Fe?As? superconductors via hydride route

    SciTech Connect (OSTI)

    Zaikina, Julia V. [Univ. of California at Davis, Davis, CA (United States); Batuk, Maria [Univ. of Antwerp, Antwerp (Belgium); Abakumov, Artem M. [Univ. of Antwerp, Antwerp (Belgium); Navrotsky, Alexandra [Univ. of California at Davis, Davis, CA (United States); Kauzlarich, Susan M. [Univ. of California at Davis, Davis, CA (United States)

    2014-12-03

    We have developed a fast, easy, and scalable synthesis method for Ba<sub>1-xsub>Kx>Fe?As? (0 ? x ? 1) superconductors using hydrides BaH? and KH as a source of barium and potassium metals. Synthesis from hydrides provides better mixing and easier handling of the starting materials, consequently leading to faster reactions and/or lower synthesis temperatures. The reducing atmosphere provided by the evolved hydrogen facilitates preparation of oxygen-free powders. By a combination of methods we have shown that Ba<sub>1-xsub>Kx>Fe?As? obtained via hydride route has the same characteristics as when it is prepared by traditional solid-state synthesis. Refinement from synchrotron powder X-ray diffraction data confirms a linear dependence of unit cell parameters upon K content as well as the tetragonal to orthorhombic transition at low temperatures for compositions with x < 0.2. Magnetic measurements revealed dome-like dependence of superconducting transition temperature T<sub>c> upon K content with a maximum of 38 K for x close to 0.4. Electron diffraction and high-resolution high-angle annular dark-field scanning transmission electron microscopy indicates an absence of Ba/K ordering, while local inhomogeneity in the Ba/K distribution takes place at a scale of several angstroms along [110] crystallographic direction.

  18. Nanocrystallization in spark plasma sintered Fe{sub 48}Cr{sub 15}Mo{sub 14}Y{sub 2}C{sub 15}B{sub 6} bulk amorphous alloy

    SciTech Connect (OSTI)

    Singh, Ashish; Harimkar, Sandip P.; Katakam, Shravana; Dahotre, Narendra B.; Ilavsky, Jan

    2013-08-07

    Spark plasma sintering (SPS) is evolving as an attractive process for the processing of multi-component Fe-based bulk amorphous alloys and their in-situ nanocomposites with controlled primary nanocrystallization. Extended Q-range small angle neutron scattering (EQ-SANS) analysis, complemented by x-ray diffraction and transmission electron microscopy, was performed to characterize nanocrystallization behavior of SPS sintered Fe-based bulk amorphous alloys. The SANS experiments show significant scattering for the samples sintered in the supercooled region indicating local structural/compositional changes associated with the profuse nucleation of nanoclusters (∼4 nm). For the samples spark plasma sintered near and above crystallization temperature (>653 °C), the SANS data show the formation of interference maximum indicating the formation and growth of (Fe,Cr){sub 23}C{sub 6} crystallites. The SANS data also indicate the evolution of bimodal crystallite distribution at higher sintering temperatures (above T{sub x1}). The growth of primary nanocrystallites results in impingement of concentration gradient fields (soft impingement effect), leading to non-random nucleation of crystallites near the primary crystallization.

  19. Sub-micron filter

    DOE Patents [OSTI]

    Tepper, Frederick; Kaledin, Leonid

    2009-10-13

    Aluminum hydroxide fibers approximately 2 nanometers in diameter and with surface areas ranging from 200 to 650 m.sup.2/g have been found to be highly electropositive. When dispersed in water they are able to attach to and retain electronegative particles. When combined into a composite filter with other fibers or particles they can filter bacteria and nano size particulates such as viruses and colloidal particles at high flux through the filter. Such filters can be used for purification and sterilization of water, biological, medical and pharmaceutical fluids, and as a collector/concentrator for detection and assay of microbes and viruses. The alumina fibers are also capable of filtering sub-micron inorganic and metallic particles to produce ultra pure water. The fibers are suitable as a substrate for growth of cells. Macromolecules such as proteins may be separated from each other based on their electronegative charges.

  20. Controlling superconductivity in La<sub>2-xsub>SrxCuO>4+?sub> by ozone and vacuum annealing

    SciTech Connect (OSTI)

    Leng, Xiang; Bozovic, Ivan

    2014-11-21

    In this study we performed a series of ozone and vacuum annealing experiments on epitaxial La<sub>2-xsub>SrxCuO>4+?sub> thin films. The transition temperature after each annealing step has been measured by the mutual inductance technique. The relationship between the effective doping and the vacuum annealing time has been studied. Short-time ozone annealing at 470 C oxidizes an underdoped film all the way to the overdoped regime. The subsequent vacuum annealing at 350 C to 380 C slowly brings the sample across the optimal doping point back to the undoped, non-superconducting state. Several ozone and vacuum annealing cycles have been done on the same sample and the effects were found to be repeatable and reversible Vacuum annealing of ozone-loaded LSCO films is a very controllable process, allowing one to tune the doping level of LSCO in small steps across the superconducting dome, which can be used for fundamental physics studies.

  1. Electron-phonon coupling and thermal transport in the thermoelectric compound Mo<sub>3sub>Sb>7–xsub>Tex>

    SciTech Connect (OSTI)

    Bansal, Dipanshu; Li, Chen W.; Said, Ayman H.; Abernathy, Douglas L.; Yan, Jiaqiang; Delaire, Olivier A.

    2015-12-07

    Phonon properties of Mo<sub>3sub>Sb>7–xsub>Tex> (x = 0, 1.5, 1.7), a potential high-temperature thermoelectric material, have been studied with inelastic neutron and x-ray scattering, and with first-principles simulations. The substitution of Te for Sb leads to pronounced changes in the electronic struc- ture, local bonding, phonon density of states (DOS), dispersions, and phonon lifetimes. Alloying with tellurium shifts the Fermi level upward, near the top of the valence band, resulting in a strong suppression of electron-phonon screening, and a large overall stiffening of interatomic force- constants. The suppression in electron-phonon coupling concomitantly increases group velocities and suppresses phonon scattering rates, surpassing the effects of alloy-disorder scattering, and re- sulting in a surprising increased lattice thermal conductivity in the alloy. We also identify that the local bonding environment changes non-uniformly around different atoms, leading to variable perturbation strengths for different optical phonon branches. The respective roles of changes in phonon group velocities and phonon lifetimes on the lattice thermal conductivity are quantified. Lastly, our results highlight the importance of the electron-phonon coupling on phonon mean-free-paths in this compound, and also estimates the contributions from boundary scattering, umklapp scattering, and point-defect scattering.

  2. Electric-field-induced strain effects on the magnetization of a Pr<sub>0.67sub>Sr>0.33sub>MnO>3sub> film

    SciTech Connect (OSTI)

    Zhang, B.; Sun, C. -J.; Lu, W.; Venkatesan, T.; Han, M. -G.; Zhu, Y.; Chen, J.; Chow, G. M.

    2015-05-26

    The electric-field control of magnetic properties of Pr<sub>0.67sub>Sr>0.33sub>MnO>3sub> (PSMO) film on piezoelectric Pb(Mg<sub>1/3sub>Nb>2/3sub>)O>3sub>-PbTiO>3sub> (PMNT) substrate was investigated. The piezoelectric response of the PMNT substrate to the electric field produced strain that was coupled to the PSMO film. The in-plane compressive (tensile) strain increased (decreased) the magnetization. The change of magnetic moment was associated with the Mn ions. First principle simulations showed that the strain-induced electronic redistribution of the two e<sub>g> orbitals (3d<sub>z>2 and 3d<sub>x>2<sub>-y>2) of Mn ions was responsible for the change of magnetic moment. This work demonstrates that the magnetoelectric effect in manganite/piezoelectric hetero-structures originates from the change in eg orbital occupancy of Mn ions induced by strain rather than the interfacial effect.

  3. Crystal structure and physical properties of quaternary clathrates Ba{sub 8}Zn{sub x}Ge{sub 46-x-y}Si{sub y}, Ba{sub 8}(Zn,Cu){sub x}Ge{sub 46-x} and Ba{sub 8}(Zn,Pd){sub x}Ge{sub 46-x}

    SciTech Connect (OSTI)

    Nasir, Navida; Grytsiv, Andriy; Melnychenko-Koblyuk, Nataliya; Rogl, Peter; Bednar, Ingeborg; Bauer, Ernst

    2010-10-15

    Three series of vacancy-free quaternary clathrates of type I, Ba{sub 8}Zn{sub x}Ge{sub 46-x-y}Si{sub y}, Ba{sub 8}(Zn,Cu){sub x}Ge{sub 46-x}, and Ba{sub 8}(Zn,Pd){sub x}Ge{sub 46-x}, have been prepared by reactions of elemental ingots in vacuum sealed quartz at 800 {sup o}C. In all cases cubic primitive symmetry (space group Pm3n, a{approx}1.1 nm) was confirmed for the clathrate phase by X-ray powder diffraction and X-ray single crystal analyses. The lattice parameters show a linear increase with increase in Ge for Ba{sub 8}Zn{sub x}Ge{sub 46-x-y}Si{sub y}. M atoms (Zn, Pd, Cu) preferably occupy the 6d site in random mixtures. No defects were observed for the 6d site. Site preference of Ge and Si in Ba{sub 8}Zn{sub x}Ge{sub 46-x-y}Si{sub y} has been elucidated from X-ray refinement: Ge atoms linearly substitute Si in the 24k site whilst a significant deviation from linearity is observed for occupation of the 16i site. A connectivity scheme for the phase equilibria in the 'Ba{sub 8}Ge{sub 46}' corner at 800 {sup o}C has been derived and a three-dimensional isothermal section at 800 {sup o}C is presented for the Ba-Pd-Zn-Ge system. Studies of transport properties carried out for Ba{sub 8{l_brace}}Cu,Pd,Zn{r_brace}{sub x}Ge{sub 46-x} and Ba{sub 8}Zn{sub x}Si{sub y}Ge{sub 46-x-y} evidenced predominantly electrons as charge carriers and the closeness of the systems to a metal-to-insulator transition, fine-tuned by substitution and mechanical processing of starting material Ba{sub 8}Ge{sub 43}. A promising figure of merit, ZT {approx}0.45 at 750 K, has been derived for Ba{sub 8}Zn{sub 7.4}Ge{sub 19.8}Si{sub 18.8}, where pricey germanium is exchanged by reasonably cheap silicon. - Graphical abstract: Quaternary phase diagram of Ba-Pd-Zn-Ge system at 800 {sup o}C.

  4. Magnetic domain structure and domain-wall energy in UFe{sub 8}Ni{sub 2}Si{sub 2} and UFe{sub 6}Ni{sub 4}Si{sub 2} intermetallic compounds

    SciTech Connect (OSTI)

    Wyslocki, J.J.; Suski, W.; Wochowski, K.

    1994-03-01

    Magnetic domain structures in the UFe{sub 8}Ni{sub 2}Si{sub 2} and UFe{sub 6}Ni{sub 4}Si{sub 2} compounds were studied using the powder pattern method. The domain structure observed is typical for uniaxial materials. The domain-wall energy density {gamma} was determined from the average surface domain width D{sub s} observed on surfaces perpendicular to the easy axis as equal to 16 erg/cm{sup 2} for UFe{sub 8}Ni{sub 2}Si{sub 2} and 10 erg/cm{sup 2} for UFe{sub 6}Ni{sub 4}Si{sub 2}. Moreover, the critical diameter for single domain particle D{sub c} was calculated for the studied compounds.

  5. Synthesis and crystal structure of (NH{sub 4}){sub 3}[UO{sub 2}(CH{sub 3}COO){sub 3}]{sub 2}[UO{sub 2}(CH{sub 3}COO)(NCS){sub 2}(H{sub 2}O)

    SciTech Connect (OSTI)

    Serezhkina, L. B.; Peresypkina, E. V.; Virovets, A. V.; Karasev, M. O.

    2010-01-15

    Single crystals of the compound (NH{sub 4}){sub 3}[UO{sub 2}(CH{sub 3}COO){sub 3}]{sub 2}[UO{sub 2}(CH{sub 3}COO)(NCS){sub 2}(H{sub 2}O)] (I) are synthesized, and their structure is investigated using X-ray diffraction. Compound I crystallizes in the monoclinic system with the unit cell parameters a = 18.3414(6) A, b = 16.3858(7) A, c = 12.4183(5) A, {beta} = 92.992(1){sup o}, space group C2/c, Z = 4, V = 3727.1(3) A{sup 3}, and R = 0.0253. The uranium-containing structural units of crystals I are mononuclear complexes of two types with an island structure, i.e., the [UO{sub 2}(CH{sub 3}COO){sub 3}]{sup -} anionic complexes belonging to the crystal-chemical group (AB{sub 3}{sup 01} = UO{sub 2}{sup 2+}, B{sup 01} = CH{sub 3}COO{sup -}) of the uranyl complexes and the [UO{sub 2}(CH{sub 3}COO)(NCS){sub 2}(H{sub 2}O)]{sup -} anionic complexes belonging to the crystal-chemical group AB{sup 01}M{sub 3}{sup 1} (A = UO{sub 2}{sup 2+}, B{sup 01} = CH{sub 3}COO{sup -}, M{sup 1} = NCS{sup -} or H{sub 2}O).

  6. Structure and optical properties of a noncentrosymmetric borate RbSr{sub 4}(BO{sub 3}){sub 3}

    SciTech Connect (OSTI)

    Xia, M.J.; Li, R.K.

    2013-01-15

    A new noncentrosymmetric borate, RbSr{sub 4}(BO{sub 3}){sub 3} (abbreviated as RSBO), has been grown from Rb{sub 2}O--B{sub 2}O{sub 3}--RbF flux and its crystal structure was determined by single crystal x-ray diffraction. It crystallizes in space group Ama2 with cell parameters of a=11.128(10) A, b=12.155(15) A, c=6.952(7) A, Z=4. The basic structural units are isolated planar BO{sub 3} groups. Second harmonic generation (SHG) test of the title compound by the Kurtz-Perry method shows that RSBO can be phase matchable with an effective SHG coefficient about two-thirds as large as that of KH{sub 2}PO{sub 4} (KDP). Finally, based on the anionic group approximation, the optical properties of the title compound are compared with those of the structure-related apatite-like compounds with the formula 'A{sub 5}(TO{sub n}){sub 3}X'. - Graphical abstract: RbSr{sub 4}(BO{sub 3}){sub 3} and some other borate NLO compounds, namely Ca{sub 5}(BO{sub 3}){sub 3}F RCa{sub 4}(BO{sub 3}){sub 3}O (R=Y or Gd) and Na{sub 3}La{sub 2}(BO{sub 3}){sub 3} can be viewed as the derivatives of apatite. They have similar formula composed of five cations and three anion groups (we call them 5/3 structures). The detailed SHG coefficients and optical properties of the apatite-like NLO crystals were compared and summarized. Highlights: Black-Right-Pointing-Pointer A new noncentrosymmetric borate RbSr{sub 4}(BO{sub 3}){sub 3} was grown from flux. Black-Right-Pointing-Pointer The RbSr{sub 4}(BO{sub 3}){sub 3} can be viewed as a derivative of the apatite-like structure. Black-Right-Pointing-Pointer The structure and its relationship to the optical properties of RbSr{sub 4}(BO{sub 3}){sub 3} are compared with other NLO crystals with apatite-like structures. Black-Right-Pointing-Pointer The basic structural units are the planar BO{sub 3} groups in the structure. Black-Right-Pointing-Pointer Second harmonic generation (SHG) test shows that RbSr{sub 4}(BO{sub 3}){sub 3} can be phase matchable with an effective SHG coefficient about two-thirds as large as that of KH{sub 2}PO{sub 4}.

  7. Direct evidence for a pressure-induced nodal superconducting gap in the Ba<sub>0.65sub>Rb>0.35sub>Fe>2sub>As>2sub> superconductor

    SciTech Connect (OSTI)

    Guguchia, Z.; Amato, A.; Kang, J.; Luetkens, H.; Biswas, P. K.; Prando, G.; von Rohr, F.; Bukowski, Z.; Shengelaya, A.; Keller, H.; Morenzoni, E.; Fernandes, Rafael M.; Khasanov, R.

    2015-11-09

    The superconducting gap structure in iron-based high-temperature superconductors (Fe-HTSs) is non-universal. Contrasting with other unconventional superconductors, in the Fe-HTSs both d-wave and extended s-wave pairing symmetries are close in energy. Probing the proximity between these very different superconducting states and identifying experimental parameters that can tune them is of central interest. Here we report high-pressure muon spin rotation experiments on the temperature-dependent magnetic penetration depth in the optimally doped nodeless s-wave Fe-HTS Ba<sub>0.65sub>Rb>0.35sub>Fe>2sub>As>2sub>. Upon pressure, a strong decrease of the penetration depth in the zero-temperature limit is observed, while the superconducting transition temperature remains nearly constant. More importantly, the low-temperature behaviour of the inverse-squared magnetic penetration depth, which is a direct measure of the superfluid density, changes qualitatively from an exponential saturation at zero pressure to a linear-in-temperature behaviour at higher pressures, indicating that hydrostatic pressure promotes the appearance of nodes in the superconducting gap.

  8. Large magnetic entropy change and magnetoresistance in a Ni<sub>41sub>Co>9sub>Mn>40sub>Sn>10sub> magnetic shape memory alloy

    SciTech Connect (OSTI)

    Huang, L.; Cong, D. Y.; Ma, L.; Nie, Z. H.; Wang, M. G.; Wang, Z. L.; Suo, H. L.; Ren, Y.; Wang, Y. D.

    2015-07-02

    A polycrystalline Ni<sub>41sub>Co>9sub>Mn>40sub>Sn>10sub> (at. %) magnetic shape memory alloy was prepared by arc melting and characterized mainly by magnetic measurements, in-situ high-energy X-ray diffraction (HEXRD), and mechanical testing. A large magnetoresistance of 53.8% (under 5 T) and a large magnetic entropy change of 31.9 J/(kg K) (under 5 T) were simultaneously achieved. Both of these values are among the highest values reported so far in Ni-Mn-Sn-based Heusler alloys. The large magnetic entropy change, closely related to the structural entropy change, is attributed to the large unit cell volume change across martensitic transformation as revealed by our in-situ HEXRD experiment. Furthermore, good compressive properties were also obtained. Lastly, the combination of large magnetoresistance, large magnetic entropy change, and good compressive properties, as well as low cost makes this alloy a promising candidate for multifunctional applications.

  9. Magnetocaloric effect in gadolinium-oxalate framework Gd{sub 2}(C{sub 2}O{sub 4}){sub 3}(H{sub 2}O){sub 6}⋅(0{sub ⋅}6H{sub 2}O)

    SciTech Connect (OSTI)

    Sibille, Romain Didelot, Emilie; Mazet, Thomas; Malaman, Bernard; François, Michel

    2014-12-01

    Magnetic refrigerants incorporating Gd{sup 3+} ions and light organic ligands offer a good balance between isolation of the magnetic centers and their density. We synthesized the framework material Gd{sub 2}(C{sub 2}O{sub 4}){sub 3}(H{sub 2}O){sub 6}⋅0.6H{sub 2}O by a hydrothermal route and characterized its structure. The honeycomb lattice of Gd{sup 3+} ions interlinked by oxalate ligands in the (a,c) plane ensures their decoupling in terms of magnetic exchange interactions. This is corroborated by magnetic measurements indicating negligible interactions between the Gd{sup 3+} ions in this material. The magnetocaloric effect was evaluated from isothermal magnetization measurements. The maximum entropy change −ΔS{sub M}{sup max} reaches 75.9 mJ cm{sup −3} K{sup −1} (around 2 K) for a moderate field change (2 T)

  10. Simulation of CO<sub>2sub> Storage

    SciTech Connect (OSTI)

    McNabb, W.; Myers, K.

    2015-10-26

    This report is a compilation of Lawrence Livermore National Laboratory’s (LLNL) accomplishments on CO<sub>2sub> storage simulation and modeling research, performed for the US-­China Clean Energy Research Center (CERC). Within the CERC project management structure, this work is referred to as Subtask 6.4.a Simulation and Modeling. The task falls under CERC’s Advanced Coal Technology Consortium (ACTC) Research Theme 6—CO<sub>2sub> Sequestration Capacity and Near-­Term Opportunities. The goals of the task were to develop new CO<sub>2sub> sequestration simulation approaches and tools, then apply them to CO<sub>2sub> storage projects in the U.S. and China. Work on this task paused when funding was redirected to CERC’s other efforts. Two sections of this report provide valuable snapshot of LLNL’s progress when funding was curtailed: 1) Section 5.2.2 is a 14-­page presentation written January 8, 2013; and 2) Section 5.1.3 is a progress report from the first quarter of Fiscal year 2013.

  11. Structure tracking aided design and synthesis of Li<sub>3sub>V>2sub>(PO>4sub>)>3sub> nanocrystals as high-power cathodes for lithium ion batteries

    SciTech Connect (OSTI)

    Wang, Liping; Bai, Jianming; Gao, Peng; Wang, Xiaoya; Looney, J. Patrick; Wang, Feng

    2015-07-30

    In this study, preparing new electrode materials with synthetic control of phases and electrochemical properties is desirable for battery applications but hardly achievable without knowing how the synthesis reaction proceeds. Herein, we report on structure tracking-aided design and synthesis of single-crystalline Li<sub>3sub>V>2sub>(PO>4sub>)>3sub> (LVP) nanoparticles with extremely high rate capability. A comprehensive investigation was made to the local structural orderings of the involved phases and their evolution toward forming LVP phase using in situ/ex situ synchrotron X-ray and electron-beam diffraction, spectroscopy, and imaging techniques. The results shed light on the thermodynamics and kinetics of synthesis reactions and enabled the design of a cost-efficient synthesis protocol to make nanocrystalline LVP, wherein solvothermal treatment is a crucial step leading to an amorphous intermediate with local structural ordering resembling that of LVP, which, upon calcination at moderate temperatures, rapidly transforms into the desired LVP phase. The obtained LVP particles are about 50 nm, coated with a thin layer of amorphous carbon and featured with excellent cycling stability and rate capability – 95% capacity retention after 200 cycles and 66% theoretical capacity even at a current rate of 10 C. The structure tracking based method we developed in this work offers a new way of designing battery electrodes with synthetic control of material phases and properties.

  12. Ordered structures in YBa/sub 2/Cu/sub 3/O/sub 7-y/, La/sub 2-x/Sr/sub x/CuO/sub 4-par. delta/ and related perovskites

    SciTech Connect (OSTI)

    Mitchell, T.E.; Roy, T.; Fisk, Z.; Smith, J.L.

    1988-01-01

    Electron microscopy and electron diffraction studies have been performed on the superconducting oxides YBa/sub 2/Cu/sub 3/O/sub 7-y/, GdBa/sub 2/Cu/sub 3/O/sub 7-y/ and La/sub 2-x/Sr/sub x/CuO/sub 4-par. delta/ as well as the related perovskites La/sub 2/CuO/sub 4/, Eu/sub 2/CuO/sub 4/ and Gd/sub 2/CuO/sub 4/. Extra reflections are commonly observed in all the cases. For example, in the 123 compounds, in situ heating leads to transformations from orthorhombic to tetragonal with a loss of twin structure; on cooling the oxygen vacancies re-order in the basal plane to give 1/3(100)* or 1/4(110)* diffraction spots. In tetragonal Eu/sub 2/CuO/sub 4/ and Gd/sub 2/CuO/sub 4/, the (001) diffraction patterns often have extra spots at 1/2(110)* or at 1/4(110)* positions. Extra spots are also observed in La/sub 2/CuO/sub 4/ (orthorhombic) but this is probably due to the space group being primitive rather than centered. These observations are discussed in terms of the ordering of oxygen vacancies in the Cu-O planes of the various perovskite structures. 6 figs.

  13. In Situ Foaming of Porous (La <sub>0.6sub> Sr <sub>0.4sub> ) <sub>0.98sub> (Co <sub>0.2sub> Fe <sub>0.8sub> ) O <sub>3−δsub> (LSCF) Cathodes for Solid Oxide Fuel Cell Applications

    SciTech Connect (OSTI)

    Gandavarapu, Sodith; Sabolsky, Edward; Sabolsky, Katarzyna; Gerdes, Kirk

    2015-01-01

    A binder system containing polyurethane precursors was used to in situ foam (direct foam) a (La{sub 0.6}Sr{sub 0.4}){sub 0.98} (Co{sub 0.2} Fe{sub 0.8}) O{sub 3-{#2;delta}} (LSCF) composition for solid oxide fuel cell (SOFC) cathode applications. The relation between in situ foaming parameters on the final microstructure and electrochemical properties was characterized by microscopy and electrochemical impedance spectroscopy (EIS), respectively. The optimal porous cathode architecture was formed with a 70 vol% solids loading within a polymer precursor composition with a volume ratio of 8:4:1 (isocyanate: PEG: surfactant) in a terpineol-based ink vehicle. The resultant microstructure displayed a broad pore size distribution with highly elongated pore structure.

  14. Influence of Yb{sub 2}O{sub 3} on electrical and microstructural

    Office of Scientific and Technical Information (OSTI)

    characteristics of CaCu{sub 3}Ti{sub 4}O{sub 12} ceramics (Journal Article) | SciTech Connect Influence of Yb{sub 2}O{sub 3} on electrical and microstructural characteristics of CaCu{sub 3}Ti{sub 4}O{sub 12} ceramics Citation Details In-Document Search Title: Influence of Yb{sub 2}O{sub 3} on electrical and microstructural characteristics of CaCu{sub 3}Ti{sub 4}O{sub 12} ceramics Graphical abstract: Some Yb atoms entered in the lattice of CCTO substituted the Ca sites, the rest of Yb atoms

  15. Magnetic measurements on ??CS{sub 2}U{sub 4}O{sub 12}

    SciTech Connect (OSTI)

    Kanrar, Buddhadev Misra, N. L.; Sastry, P. U.; Dube, V.; Ravikumar, G.

    2014-04-24

    Magnetic and XRD measurements on ??CS{sub 2}U{sub 4}O{sub 12} having uranium in mixed valent states of U (V) and U (VI) have been made. The study reveals that the compound undergoes an antiferromagnetic transition below 25K and an anomalous magnetic behavior was seen around 75K. This anomalous behavior indicates towards a structural phase transition. However, the low temperature XRD could not confirm this observation.

  16. Correlation between upconversion photoluminescence and dielectric response in Ba-substituted (Sr{sub 1?x}Ba{sub x}){sub 4}(La{sub 0.85}Ho{sub 0.025}Yb{sub 0.125}){sub 2}Ti{sub 4}Nb{sub 6}O{sub 30}

    SciTech Connect (OSTI)

    Wei, T.; Wang, X. D.; Zhao, C. Z.; Liu, M. F.; Liu, J. M.

    2014-06-30

    The filled tetragonal tungsten bronze (Sr{sub 1?x}Ba{sub x}){sub 4}(La{sub 0.85}Ho{sub 0.025}Yb{sub 0.125}){sub 2}Ti{sub 4}Nb{sub 6}O{sub 30} (SBLTNx: Ho-Yb) ceramics with different Ba substitution levels (x) are prepared. The upconversion photoluminescence (UC-PL) and dielectric permittivity are investigated. The substitution of Sr{sup 2+} ions at the A{sub 2}-sites by larger Ba{sup 2+} ions results in substantial variation of the UC-PL intensity as a function of substitution level x. Furthermore, the dielectric response to the substitution of Sr{sup 2+} by Ba{sup 2+} suggests a close correlation between the UC-PL intensity and dielectric permittivity. The origin for this correlation is discussed based on the random stress field (RSF) model.

  17. Method of preparing (CH.sub.3).sub.3 SiNSO and byproducts thereof

    DOE Patents [OSTI]

    Spicer, Leonard D.; Bennett, Dennis W.; Davis, Jon F.

    1984-01-01

    (CH.sub.3).sub.3 SiNSO is produced by the reaction of ((CH.sub.3).sub.3 Si).sub.2 NH with SO.sub.2. Also produced in the reaction are ((CH.sub.3).sub.3 Si).sub.2 O and a new solid compound [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ]. Both (CH.sub.3).sub.3 SiNSO and [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ] have fluorescent properties. The reaction of the subject invention is used in a method of measuring the concentration of SO.sub.2 pollutants in gases. By the method, a sample of gas is bubbled through a solution of ((CH.sub.3).sub.3 Si).sub.2 NH, whereby any SO.sub.2 present in the gas will react to produce the two fluorescent products. The measured fluorescence of these products can then be used to calculate the concentration of SO.sub.2 in the original gas sample. The solid product [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ] may be used as a standard in solid state NMR spectroscopy.

  18. Measurement of the ?<sub>b>? lifetime in the exclusive decay ?<sub>b>??J/??? in pp? collisions at ?s=1.96 TeV

    SciTech Connect (OSTI)

    Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Alverson, G.; Aoki, M.; Askew, A.; Atkins, S.; Augsten, K.; Avila, C.; Badaud, F.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Barberis, E.; Baringer, P.; Barreto, J.; Bartlett, J. F.; Bassler, U.; Bazterra, V.; Bean, A.; Begalli, M.; Bellantoni, L.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besanon, M.; Beuselinck, R.; Bezzubov, V. A.; Bhat, P. C.; Bhatia, S.; Bhatnagar, V.; Blazey, G.; Blessing, S.; Bloom, K.; Boehnlein, A.; Boline, D.; Boos, E. E.; Borissov, G.; Bose, T.; Brandt, A.; Brandt, O.; Brock, R.; Brooijmans, G.; Bross, A.; Brown, D.; Brown, J.; Bu, X. B.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Buszello, C. P.; Camacho-Prez, E.; Casey, B. C. K.; Castilla-Valdez, H.; Caughron, S.; Chakrabarti, S.; Chakraborty, D.; Chan, K. M.; Chandra, A.; Chapon, E.; Chen, G.; Chevalier-Thry, S.; Cho, D. K.; Cho, S. W.; Choi, S.; Choudhary, B.; Cihangir, S.; Claes, D.; Clutter, J.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M.-C.; Croc, A.; Cutts, D.; Das, A.; Davies, G.; de Jong, S. J.; De La Cruz-Burelo, E.; Dliot, F.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Deterre, C.; DeVaughan, K.; Diehl, H. T.; Diesburg, M.; Ding, P. F.; Dominguez, A.; Dubey, A.; Dudko, L. V.; Duggan, D.; Duperrin, A.; Dutt, S.; Dyshkant, A.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Facini, G.; Feng, L.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Fortner, M.; Fox, H.; Fuess, S.; Garcia-Bellido, A.; Garca-Gonzlez, J. A.; Garca-Guerra, G. A.; Gavrilov, V.; Gay, P.; Geng, W.; Gerbaudo, D.; Gerber, C. E.; Gershtein, Y.; Ginther, G.; Golovanov, G.; Goussiou, A.; Grannis, P. D.; Greder, S.; Greenlee, H.; Grenier, G.; Gris, Ph.; Grivaz, J.-F.; Grohsjean, A.; Grnendahl, S.; Grnewald, M. W.; Guillemin, T.; Gutierrez, G.; Gutierrez, P.; Haas, A.; Hagopian, S.; Haley, J.; Han, L.; Harder, K.; Harel, A.; Hauptman, J. M.; Hays, J.; Head, T.; Hebbeker, T.; Hedin, D.; Hegab, H.; Heinson, A. P.; Heintz, U.; Hensel, C.; Heredia-De La Cruz, I.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hoang, T.; Hobbs, J. D.; Hoeneisen, B.; Hohlfeld, M.; Howley, I.; Hubacek, Z.; Hynek, V.; Iashvili, I.; Ilchenko, Y.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffr, M.; Jayasinghe, A.; Jesik, R.; Johns, K.; Johnson, E.; Johnson, M.; Jonckheere, A.; Jonsson, P.; Joshi, J.; Jung, A. W.; Juste, A.; Kaadze, K.; Kajfasz, E.; Karmanov, D.; Kasper, P. A.; Katsanos, I.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. N.; Kiselevich, I.; Kohli, J. M.; Kozelov, A. V.; Kraus, J.; Kulikov, S.; Kumar, A.; Kupco, A.; Kur?a, T.; Kuzmin, V. A.; Lammers, S.; Landsberg, G.; Lebrun, P.; Lee, H. S.; Lee, S. W.; Lee, W. M.; Lellouch, J.; Li, H.; Li, L.; Li, Q. Z.; Lim, J. K.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, H.; Liu, Y.; Lobodenko, A.; Lokajicek, M.; Lopes de Sa, R.; Lubatti, H. J.; Luna-Garcia, R.; Lyon, A. L.; Maciel, A. K. A.; Madar, R.; Magaa-Villalba, R.; Malik, S.; Malyshev, V. L.; Maravin, Y.; Martnez-Ortega, J.; McCarthy, R.; McGivern, C. L.; Meijer, M. M.; Melnitchouk, A.; Menezes, D.; Mercadante, P. G.; Merkin, M.; Meyer, A.; Meyer, J.; Miconi, F.; Mondal, N. K.; Mulhearn, M.; Nagy, E.; Naimuddin, M.; Narain, M.; Nayyar, R.; Neal, H. A.; Negret, J. P.; Neustroev, P.; Nunnemann, T.; Obrant, G.; Orduna, J.; Osman, N.; Osta, J.; Padilla, M.; Pal, A.; Parashar, N.; Parihar, V.; Park, S. K.; Partridge, R.; Parua, N.; Patwa, A.; Penning, B.; Perfilov, M.; Peters, Y.; Petridis, K.; Petrillo, G.; Ptroff, P.; Pleier, M.-A.; Podesta-Lerma, P. L. M.; Podstavkov, V. M.; Popov, A. V.; Prewitt, M.; Price, D.; Prokopenko, N.; Qian, J.; Quadt, A.; Quinn, B.; Rangel, M. S.; Ranjan, K.; Ratoff, P. N.; Razumov, I.; Renkel, P.; Ripp-Baudot, I.; Rizatdinova, F.; Rominsky, M.; Ross, A.; Royon, C.; Rubinov, P.; Ruchti, R.; Sajot, G.; Salcido, P.; Snchez-Hernndez, A.; Sanders, M. P.; Sanghi, B.; Santos, A. S.; Savage, G.; Sawyer, L.; Scanlon, T.; Schamberger, R. D.; Scheglov, Y.; Schellman, H.; Schlobohm, S.; Schwanenberger, C.; Schwienhorst, R.; Sekaric, J.; Severini, H.; Shabalina, E.; Shary, V.; Shaw, S.; Shchukin, A. A.; Shivpuri, R. K.; Simak, V.; Skubic, P.; Slattery, P.; Smirnov, D.; Smith, K. J.; Snow, G. R.; Snow, J.; Snyder, S.; Sldner-Rembold, S.; Sonnenschein, L.; Soustruznik, K.; Stark, J.; Stoyanova, D. A.; Strauss, M.; Stutte, L.; Suter, L.; Svoisky, P.; Takahashi, M.; Titov, M.; Tokmenin, V. V.; Tsai, Y.-T.; Tschann-Grimm, K.; Tsybychev, D.; Tuchming, B.; Tully, C.; Uvarov, L.; Uvarov, S.; Uzunyan, S.; Van Kooten, R.

    2012-06-07

    We measure the ??<sub>b> lifetime in the fully reconstructed decay ??<sub>b>?J/??? using 10.4 fb? of pp? collisions collected with the D0 detector at ?s=1.96 TeV. The lifetime of the topologically similar decay channel B??J/?K?<sub>S> is also measured. We obtain ?(??<sub>b>)=1.3030.075(stat)0.035(syst) ps and ?(B?)=1.5080.025(stat)0.043(syst) ps. Using these measurements, we determine the lifetime ratio of ?(??<sub>b>)/?(B?)=0.8640.052(stat)0.033(syst).

  19. Crystallographic, electronic, thermal, and magnetic properties of single-crystal SrCo<sub>2sub>As>2sub>

    SciTech Connect (OSTI)

    Pandey, Abhishek; Quirinale, D. G.; Jayasekara, W.; Sapkota, A.; Kim, M. G.; Dhaka, R. S.; Lee, Y.; Heitmann, T. W.; Stephens, P. W.; Ogloblichev, V.; Kreyssig, A.; McQueeney, R. J.; Goldman, A. I.; Kaminski, Adam; Harmon, B. N.; Furukawa, Y.; Johnston, D. C.

    2013-07-01

    In tetragonal SrCo<sub>2sub>As>2 sub>single crystals, inelastic neutron scattering measurements demonstrated that strong stripe-type antiferromagnetic (AFM) correlations occur at a temperature T = 5 K [W. Jayasekara et al., arXiv:1306.5174] that are the same as in the isostructural AFe<sub>2sub>As>2sub> (A = Ca, Sr, Ba) parent compounds of high-T<sub>c> superconductors. This surprising discovery suggests that SrCo<sub>2sub>As>2sub> may also be a good parent compound for high-T<sub>c sub>superconductivity. Here, structural and thermal expansion, electrical resistivity ?, angle-resolved photoemission spectroscopy (ARPES), heat capacity C<sub>p>, magnetic susceptibility ?, 75As NMR and neutron diffraction measurements of SrCo<sub>2sub>As>2sub> crystals are reported together with LDA band structure calculations that shed further light on this fascinating material. The c-axis thermal expansion coefficient ?<sub>c> is negative from 7 to 300 K, whereas ?<sub>a> is positive over this T range. The ?(T) shows metallic character. The ARPES measurements and band theory confirm the metallic character and in addition show the presence of a flat band near the Fermi energy E<sub>F>. The band calculations exhibit an extremely sharp peak in the density of states D(E<sub>F>) arising from a flat d<sub>x2-y2sub> band. A comparison of the Sommerfeld coefficient of the electronic specific heat with ?(T ? 0) suggests the presence of strong ferromagnetic itinerant spin correlations which on the basis of the Stoner criterion predicts that SrCo<sub>2sub>As>2sub> should be an itinerant ferromagnet, in conflict with the magnetization data. The ?(T) does have a large magnitude, but also exhibits a broad maximum at 115 K suggestive of dynamic short-range AFM spin correlations, in agreement with the neutron scattering data. The measurements show no evidence for any type of phase transition between 1.3 and 300 K and we propose that metallic SrCo<sub>2sub>As>2sub> has a gapless quantum spin-liquid ground state.

  20. Branching Fraction and CP Asymmetry Measurements in Inclusive B ? X<sub>s> ???? and B ? X<sub>s>? Decays from BABAR

    SciTech Connect (OSTI)

    Eigen, G.

    2015-04-29

    We present an update on total and partial branching fractions and on CP asymmetries in the semi-inclusive decay B ? X<sub>s>???-. Further, we summarize our results on branching fractions and CP asymmetries for semi-inclusive and fully-inclusive B ? X<sub>s>? decays. We present the first result on the CP asymmetry diff erence of charged and neutral B ? X<sub>s>? decays yielding the first constraint on the ratio of Wilson coeffi cients Im(C<sub>8sub>eff/C>7sub>eff).

  1. Reaction-bonding preparation of Si{sub 3}N{sub 4}/MoSi{sub 2} and Si{sub 3}N{sub 4}/WSi{sub 2} composites from elemental powders

    SciTech Connect (OSTI)

    Zhang, B.R.; Marino, F.

    1997-01-01

    Si{sub 3}N{sub 4}/MoSi{sub 2} and Si{sub 3}N{sub 4}/WSi{sub 2} composites were prepared by reaction-bonding processes using as starting materials powder mixtures of Si-Mo and Si-W, respectively. A presintering step in an Ar-base atmosphere was used before nitriding for the formation of MoSi{sub 2} and WSi{sub 2}; the nitridation in a N{sub 2}-base atmosphere was followed after presintering with the total stepwise cycle of 1,350 C {times} 20 h + 1,400 C {times} 20 h + 1,450 C {times} 2 h. The final phases obtained in the two different composites were Si{sub 3}N{sub 4} and MoSi{sub 2} or WSi{sub 2}; no free elemental Si and Mo or W were detected by X-ray diffraction.

  2. Josephson junctions in high-T/sub c/ superconductors

    DOE Patents [OSTI]

    Falco, C.M.; Lee, T.W.

    1981-01-14

    The invention includes a high T/sub c/ Josephson sperconducting junction as well as the method and apparatus which provides the junction by application of a closely controlled and monitored electrical discharge to a microbridge region connecting two portions of a superconducting film.

  3. Li{sub 2}B{sub 3}O{sub 4}F{sub 3}, a new lithium-rich fluorooxoborate

    SciTech Connect (OSTI)

    Pilz, Thomas; Nuss, Hanne; Jansen, Martin

    2012-02-15

    The new lithium fluorooxoborate, Li{sub 2}B{sub 3}O{sub 4}F{sub 3}, is obtained by a solid state reaction from LiBO{sub 2} and LiBF{sub 4} at 553 K and crystallizes in the acentric orthorhombic space group P2{sub 1}2{sub 1}2{sub 1} (no. 19) with the cell parameters a=4.8915(9), b=8.734(2), and c=12.301(2) A. Chains of fluorinated boroxine rings along the b axis consists of BO{sub 3} triangles and BO{sub 2}F{sub 2} as well as BO{sub 3}F tetrahedra. Mobile lithium ions are compensating the negative charge of the anionic chain, in which the fourfold coordinated boron atoms bear a negative formal charge. Annealing Li{sub 2}B{sub 3}O{sub 4}F{sub 3} at temperatures above 573 K leads to conversion into Li{sub 2}B{sub 6}O{sub 9}F{sub 2}. The title compound is an ionic conductor with the highest ion conductivity among the hitherto know lithium fluorooxoborates, with conductivities of 1.6 Multiplication-Sign 10{sup -9} and 1.8 Multiplication-Sign 10{sup -8} S cm{sup -1} at 473 and 523 K, respectively. - Graphical abstract: Repetition unit of Li{sub 2}B{sub 3}O{sub 4}F{sub 3}. Highlights: Black-Right-Pointing-Pointer Li{sub 2}B{sub 3}O{sub 4}F{sub 3} is the third member within the family of lithium fluorooxoborates. Black-Right-Pointing-Pointer It shows the highest lithium ion conductivity among them. Black-Right-Pointing-Pointer Chains of interconnected fluorinated boroxine rings run along the b axis. Black-Right-Pointing-Pointer Acentric space group meets the requirement for second harmonic generation.

  4. An in-situ phosphorus source for the synthesis of Cu<sub>3sub>P and the subsequent conversion to Cu<sub>3sub>PS>4sub> nanoparticle clusters

    SciTech Connect (OSTI)

    Sheets, Erik J.; Stach, Eric A.; Yang, Wei -Chang; Balow, Robert B.; Wang, Yunjie; Walker, Bryce C.; Agrawal, Rakesh

    2015-09-20

    The search for alternative earth abundant semiconducting nanocrystals for sustainable energy applications has brought forth the need for nanoscale syntheses beyond bulk synthesis routes. Of particular interest are metal phosphides and derivative I-V-VI chalcogenides including copper phosphide (Cu<sub>3sub>P) and copper thiophosphate (Cu<sub>3sub>PS>4sub>). Herein, we report a one-pot, solution-based synthesis of Cu<sub>3sub>P nanocrystals utilizing an in-situ phosphorus source: phosphorus pentasulfide (P<sub>2sub>S>5sub>) in trioctylphosphine (TOP). By injecting this phosphorus source into a copper solution in oleylamine (OLA), uniform and size controlled Cu<sub>3sub>P nanocrystals with a phosphorous-rich surface are synthesized. The subsequent reaction of the Cu<sub>3sub>P nanocrystals with decomposing thiourea forms nanoscale Cu<sub>3sub>PS>4sub> particles having p-type conductivity and an effective optical band gap of 2.36 eV.

  5. Precipitate size refinement by CeO{sub 2} and Y{sub 2}BaCuO{sub 5} additions in directionally solidified YBa{sub 2}Cu{sub 3}O{sub 7}

    SciTech Connect (OSTI)

    Vilalta, N.; Sandiumenge, F.; Pinol, S.; Obradors, X.

    1997-01-01

    Directional solidification of YBa{sub 2}Cu{sub 3}O{sub 7} has been carried out through a Bridgman technique, and the influence of Y{sub 2}BaCuO{sub 5} and CeO{sub 2} additives on the size of Y{sub 2}BaCuO{sub 5} precipitates has been investigated. It is demonstrated in this work that the most efficient procedure to reduce the size of the Y{sub 2}BaCuO{sub 5} precipitates is to increase the concentration of nucleation centers present in the peritectic decomposition of YBa{sub 2}Cu{sub 3}O{sub 7{minus}x}. A small concentration (0.3{endash}1 wt.{percent}) of CeO{sub 2} has a strong influence on the solidification process and on the size of Y{sub 2}BaCuO{sub 5} precipitates. It is shown that when CeO{sub 2} is added, further refinement of the size of precipitates results from the formation of nanometric Y{sub 2}O{sub 3} particles which further enhance the multinucleation effect. We have also observed that coarsening effects are avoided with CeO{sub 2} additives. {copyright} {ital 1997 Materials Research Society.}

  6. Electronic and optical properties of layered RE{sub 2}Ti{sub 2}O{sub 7} (RE = Ce and Pr) from first principles

    SciTech Connect (OSTI)

    Sayede, A.; Khenata, R.; Chahed, A.; Benhelal, O.

    2013-05-07

    We have studied the structural and electronic properties of Ce{sub 2}Ti{sub 2}O{sub 7} (CeTO) and Pr{sub 2}Ti{sub 2}O{sub 7} (PrTO) by first-principles density functional theory calculations. The computed structural parameters are in fairly good agreement with the available experimental findings. Band structure calculations using the GGA+U approach predict an insulating ground state for the herein studied compounds. The insulating band gaps of 2.00 eV and 2.83 eV are found for CeTO and PrTO, respectively. The analysis of the density of states reveals that the strongly localized RE 4f levels act as charge-trapping sites, predicting a lower photocatalytic activity for CeTO. We have also calculated the optical properties for both CeTO and PrTO. Based on these properties, it is predicted that these titanates are insensitive to ultra-violet radiation, while they are more sensitive to frequencies of the radiation in visible and early UV regions.

  7. Characteristics of atmospheric-pressure non-thermal N{sub 2} and N{sub 2}/O{sub 2} gas mixture plasma jet

    SciTech Connect (OSTI)

    Xiao, Dezhi; Shen, Jie; Lan, Yan; Xie, Hongbing; Shu, Xingsheng; Meng, Yuedong; Li, Jiangang; Cheng, Cheng E-mail: paul.chu@cityu.edu.hk; Chu, Paul K. E-mail: paul.chu@cityu.edu.hk

    2014-01-21

    An atmospheric-pressure non-thermal plasma jet driven by high frequency alternating current and operating on N{sub 2} and N{sub 2}/O{sub 2} gas mixture is investigated. The plasma jet can reach 55?mm in length at a gas flow rate of 2500?l/h. The gas temperature at a distance of 4?mm from the nozzle is close to room temperature. Optical emission spectroscopy is employed to investigate the important plasma parameters such as the excited species, rotational temperature, vibrational temperature, and excitation temperature under different discharge conditions. The results show that the plasma source operates under non-equilibrium conditions. The absolute irradiance intensity of the vibrational band N{sub 2}(C-B) in the active region is measured. Taking into account the irradiance intensity of N{sub 2}(C-B,0-0) and N{sub 2}(B-X,0-0) as well as measured current, the electron density, which is determined by considering direct and step-wise electron impact excitation of nitrogen emission, reaches a maximum value of 5.6??10{sup 20}/m{sup 3}.

  8. Magnetic properties and photoabsorption of the Mn-doped CeO{sub 2} nanorods

    SciTech Connect (OSTI)

    Xia, Chuanhui; Science College of Chongqing Jiaotong University, Chongqing 400074 ; Hu, Chenguo; Chen, Peng; Wan, Buyong; He, Xiaoshan; Tian, Yongshu; Chongqing Communication College, Chongqing 400035

    2010-07-15

    Mn-doped CeO{sub 2} nanorods have been prepared from CeO{sub 2} particles through a facile composite-hydroxide-mediated (CHM) approach. The analysis from X-ray photoelectron spectroscopy indicates that the manganese doped in CeO{sub 2} exists as Mn{sup 2+}. The magnetic measurement of the Mn-doped CeO{sub 2} nanorods exhibits an enhanced ferromagnetic property at room temperature with a remanence magnetization (Mr) of 1.36 x 10{sup -3} emu/g and coercivity (Hc) of 22 Oe. Comparative UV-visible spectra reveal the shift of the absorption peak of the CeO{sub 2} from ultraviolet region to visible light region after being doped with Mn. The room temperature ferromagnetic properties and light absorption of the Mn-doped CeO{sub 2} nanorods would have potential applications in photocatalysis and building of photovoltaic devices.

  9. Mechanistic insight into peroxydisulfate reactivity: Oxidation of the cis,cis-[Ru(bpy)<sub>2sub>(OH>2sub>)]>2sub>O4+ "Blue Dimmer"

    SciTech Connect (OSTI)

    Hurst, James K.; Roemeling, Margo D.; Lymar, Sergei V.

    2015-04-10

    One-electron oxidation of the ?-oxo dimer (cis,cis-[RuIII(bpy)<sub>2sub>(OH>2sub>)]>2sub>O4+, {3,3}) to {3,4} by S<sub>2sub>O>8sub>2- can be described by three concurrent reaction pathways corresponding to the three protic forms of {3,3}. Free energy correlations of the rate constants, transient species dynamics determined by pulse radiolysis, and medium and temperature dependencies of the alkaline pathway all suggest that the rate determining step in these reactions is a strongly non-adiabatic dissociative electron transfer within a precursor ion pair leading to the {3,4}|SO<sub>4sub>2-|SO<sub>4sub>- ion triple. As deduced from the SO<sub>4sub>- scavenging experiments with 2-propanol, the SO<sub>4sub>- radical then either oxidizes {3,4} to {4,4} within the ion triple, effecting a net two-electron oxidation of {3,3}, or escapes in solution with ~25 % probability to react with additional {3,3} and {3,4}, that is, effecting sequential one-electron oxidations. The reaction model presented also invokes rapid {3,3} + {4,4} ? 2{3,4} comproportionation, for which k<sub>com> ~5107 M-1 s-1 was independently measured. The model provides an explanation for the observation that despite favorable energetics, no oxidation beyond the {3,4} state was detected. As a result, the indiscriminate nature of oxidation by SO<sub>4sub>- indicates that its fate must be quantitatively determined when using S<sub>2sub>O>8sub>2- as an oxidant

  10. Low Temperature Propane Oxidation over Co<sub>3sub>O>4sub> based Nano-array Catalysts. Ni Dopant Effect, Reaction Mechanism and Structural Stability

    SciTech Connect (OSTI)

    Ren, Zheng; Wu, Zili; Gao, Puxian; Song, Wenqiao; Xiao, Wen; Guo, Yanbing; Ding, Jun; Suib, Steven L.; Gao, Pu-Xian

    2015-06-09

    Low temperature propane oxidation has been achieved by Co<sub>3sub>O>4sub>-based nano-array catalysts featuring low catalytic materials loading. The Ni doping into the Co<sub>3sub>O>4sub> lattice has led to enhanced reaction kinetics at low temperature by promoting the surface lattice oxygen activity. In situ DRIFTS investigation in tandem with isotopic oxygen exchange reveals that the propane oxidation proceeds via Mars-van Krevelen mechanism where surface lattice oxygen acts as the active site whereas O<sub>2sub> in the reaction feed does not directly participate in CO<sub>2sub> formation. The Ni doping promotes the formation of less stable carbonates on the surface to facilitate the CO<sub>2sub> desorption. The thermal stability of Ni doped Co<sub>3sub>O>4sub> decreases with increased Ni concentration while catalytic activity increases. A balance between enhanced activity and compromised thermal stability shall be considered in the Ni doped Co<sub>3sub>O>4sub> nano-array catalysts for low temperature hydrocarbon oxidation. This study provides useful and timely guidance for rational catalyst design toward low temperature catalytic oxidation.

  11. CuCo<sub>2sub>O>4sub> ORR/OER Bi-functional catalyst: Influence of synthetic approach on performance

    SciTech Connect (OSTI)

    Serov, Alexey; Andersen, Nalin I.; Roy, Aaron J.; Matanovic, Ivana; Artyushkova, Kateryna; Atanassov, Plamen

    2015-02-07

    A series of CuCo<sub>2sub>O>4sub> catalysts were synthesized by pore forming, sol-gel, spray pyrolysis and sacrificial support methods. Catalysts were characterized by XRD, SEM, XPS and BET techniques. The electrochemical activity for the oxygen reduction and oxygen evolution reactions (ORR and OER) was evaluated in alkaline media by RRDE. Density Functional Theory was used to identify two different types of active sites responsible for ORR/OER activity of CuCo<sub>2sub>O>4sub> and it was found that CuCo<sub>2sub>O>4 sub>can activate the O-O bond by binding molecular oxygen in bridging positions between Co or Co and Cu atoms. It was found that the sacrificial support method (SSM) catalyst has the highest performance in both ORR and OER and has the highest content of phase-pure CuCo<sub>2sub>O>4sub>. It was shown that the presence of CuO significantly decreases the activity in oxygen reduction and oxygen evolution reactions. As a result, the half-wave potential (E<sub>1/2sub>) of CuCo<sub>2sub>O>4sub>-SSM was found as 0.8 V, making this material a state-of-the-art, unsupported oxide catalyst.

  12. Itinerant Antiferromagnetism in FeMnP<sub>0.8sub>Si>0.2sub>

    SciTech Connect (OSTI)

    Sales, Brian C.; Susner, Michael A.; Conner, Benjamin S.; Yan, Jiaqiang Q.; May, Andrew F.

    2015-09-25

    Compounds based on the Fe<sub>2sub>P structure have continued to attract interest because of the interplay between itinerant and localized magnetism in a noncentrosymmetric crystal structure, and because of the recent developments of these materials for magnetocaloric applications. We report the growth and characterization of millimeter-sized single crystals of FeMnP<sub>0.8sub>Si>0.2sub> with the Fe<sub>2sub>P structure. Single-crystal x-ray diffraction, magnetization, resistivity, and Hall and heat capacity data are reported. The crystals exhibit itinerant antiferromagnetic order below 158 K with no hint of ferromagnetic behavior in the magnetization curves and with the spins ordered primarily in the ab plane. The room-temperature resistivity is close to the Ioffe-Regel limit for a metal. Single-crystal x-ray diffraction indicates a strong preference for Mn to occupy the larger pyramidal 3g site. The cation site preference in the as-grown crystals and the antiferromagnetism were not changed after high-temperature anneals and a rapid quench to room temperature

  13. SO.sub.2 sensor

    DOE Patents [OSTI]

    Dalla Betta, Ralph A. (Mountain View, CA); Sheridan, David R. (Menlo Park, CA)

    1994-01-01

    This invention is a process for detecting low concentration levels of sulfur oxides (SO.sub.2) in a flowing gas stream (typically a combustion exhaust gas stream) and a catalytic SO.sub.2 sensor system which may be used in that process.

  14. Southwest Regional Partnership on Carbon Sequestration

    SciTech Connect (OSTI)

    Brian McPherson

    2006-03-31

    The Southwest Partnership on Carbon Sequestration completed its Phase I program in December 2005. The main objective of the Southwest Partnership Phase I project was to evaluate and demonstrate the means for achieving an 18% reduction in carbon intensity by 2012. Many other goals were accomplished on the way to this objective, including (1) analysis of CO{sub 2} storage options in the region, including characterization of storage capacities and transportation options, (2) analysis and summary of CO{sub 2} sources, (3) analysis and summary of CO{sub 2} separation and capture technologies employed in the region, (4) evaluation and ranking of the most appropriate sequestration technologies for capture and storage of CO{sub 2} in the Southwest Region, (5) dissemination of existing regulatory/permitting requirements, and (6) assessing and initiating public knowledge and acceptance of possible sequestration approaches. Results of the Southwest Partnership's Phase I evaluation suggested that the most convenient and practical ''first opportunities'' for sequestration would lie along existing CO{sub 2} pipelines in the region. Action plans for six Phase II validation tests in the region were developed, with a portfolio that includes four geologic pilot tests distributed among Utah, New Mexico, and Texas. The Partnership will also conduct a regional terrestrial sequestration pilot program focusing on improved terrestrial MMV methods and reporting approaches specific for the Southwest region. The sixth and final validation test consists of a local-scale terrestrial pilot involving restoration of riparian lands for sequestration purposes. The validation test will use desalinated waters produced from one of the geologic pilot tests. The Southwest Regional Partnership comprises a large, diverse group of expert organizations and individuals specializing in carbon sequestration science and engineering, as well as public policy and outreach. These partners include 21 state government agencies and universities, five major electric utility companies, seven oil, gas and coal companies, three federal agencies, the Navajo Nation, several NGOs, and the Western Governors Association. This group is continuing its work in the Phase II Validation Program, slated to conclude in 2009.

  15. Kondo Physics and Unconventional Superconductivity in the U Intermetallic U<sub>2sub>PtC>2sub> Revealed by NMR

    SciTech Connect (OSTI)

    Mounce, Andrew M.; Thompson, Joe David

    2015-12-17

    The set of slides begins by discussing the topic NMR of heavy fermion superconductors under the topics heavy fermion materials, superconductivity, and nuclear magnetic resonance. The history of these phenomena is sketched, with particular mention made of CeCu<sub>2sub>Si>2sub>, UPt<sub>3sub>, and UBe<sub>13sub>. Unconventional superconductivity, which is non-phonon mediated superconductivity, presents a high T<sub>c> (up to ~150 K), and involves a more complicated spin/orbital wave function. The presentation then goes on to give experimental NMR results for U<sub>2sub>PtC>2sub> and Pu-115’s.

  16. Dopant-Induced Nanoscale Electronic Inhomogeneities in Ca<sub>2-xsub>SrxRuO>4sub>

    SciTech Connect (OSTI)

    Zhang, Jiandi; Ismail, #; Moore, R. G.; Wang, S. -C.; Ding, H.; Jin, Rongying; Mandrus, David; Plummer, E Ward

    2006-01-01

    Ca{sub 2-x}Sr{sub x}RuO{sub 4} single crystals with 0.1 {le} x {le} 2.0 have been studied systematically using scanning tunneling microscopy (STM) and spectroscopy, low-energy electron diffraction, and angle resolved photoelectron spectroscopy (ARPES). In contrast with the well-ordered lattice structure, the local density of states at the surface clearly shows a strong doping dependent nanoscale electronic inhomogeneity, regardless of the fact of isovalent substitution. Remarkably, the surface electronic roughness measured by STM and the inverse spectral weight of quasiparticle states determined by ARPES are found to vary with x in the same manner as the bulk in-plane residual resistivity, following the Nordheim rule. For the first time, the surface measurements - especially those with STM - are shown to be in good agreement with the bulk transport results, all clearly indicating a doping-induced electronic disorder in the system.

  17. Hydrothermal crystallization of Na{sub 2}Ti{sub 6}O{sub 13}, Na{sub 2}Ti{sub 3}O{sub 7}, and Na{sub 16}Ti{sub 10}O{sub 28} in the NaOH-TiO{sub 2}-H{sub 2}O system at a temperature of 500 deg. C and a pressure of 0.1 GPa: The structural mechanism of self-assembly of titanates from suprapolyhedral clusters

    SciTech Connect (OSTI)

    Hyushin, G. D.

    2006-07-15

    An increase in the NaOH concentration in the NaOH-TiO{sub 2} (rutile)-H{sub 2}O system at a temperature of 500 deg. C and a pressure of 0.1 GPa leads to the crystallization R-TiO{sub 2} + Na{sub 2}Ti{sub 6}O{sub 13} {sup {yields}} Na{sub 2}Ti{sub 3}O{sub 7} {sup {yields}} Na{sub 16}Ti{sub 10}O{sub 28}. Crystals of the Na{sub 2}Ti{sub 6}O{sub 13} titanate (space group C2/m) have the three-dimensional framework structure Ti{sub 6}O{sub 13}. The structure of the Na{sub 2}Ti{sub 3}O{sub 7} titanate (space group P2{sub 1}/m) contains the two-dimensional layers Ti{sub 3}O{sub 7}. The structure of the Na{sub 16}Ti{sub 10}O{sub 28} titanate (space group P-1) is composed of the isolated ten-polyhedron cluster precursors Ti{sub 10}O{sub 28}. In all the structures, the titanium atoms have an octahedral coordination (MTiO{sub 6}). The matrix self-assembly of the Na{sub 2}Ti{sub 6}O{sub 13} and Na{sub 2}Ti{sub 3}O{sub 7} (Na{sub 4}Ti{sub 6}O{sub 14}) crystal structures from Na{sub 4}M{sub 12} invariant precursors is modeled. These precursors are clusters consisting of twelve M polyhedra linked through the edges. It is demonstrated that the structurally rigid precursors Na{sub 4}M{sub 12} control all processes of the subsequent evolution of the crystal-forming titanate clusters. The specific features of the self-assembly of the Na{sub 2}Ti{sub 3}O{sub 7} structure that result from the additional incorporation of twice the number of sodium atoms into the composition of the high-level clusters are considered.

  18. Low NO sub x /SO sub x Burner retrofit for utility cyclone boilers

    SciTech Connect (OSTI)

    Not Available

    1990-01-01

    Cyclone furnaces operate with high excess air and at high temperature. The heat release during combustion is very high and as a result the boiler volume is much smaller than would be found in a conventional pc-fired system. The Marion Unit 1 boiler, at the level of the cyclone entry, has a small cross-section; about 5-feet in depth and about 20-feet in width. A boiler schematic showing the LNS Burner and relative location of the superheater region and overfire air ports is shown in Figure 1. The LNS Burner's combustion process is fundamentally different from that of the cyclone, and the combustion products are also different. The LNS Burner products enter the boiler as hot, fuel-rich gases. Additional overfire air must be added to complete this combustion step with care taken to avoid the formation of thermal NO{sub x}. If done correctly, S0{sub 2} is controlled and significant NO{sub x} reductions are achieved. Because of the small boiler volume, flow modelling was found to be necessary to insure that adequate mixing of LNS Burner combustion products with air can be accomplished to achieve NO{sub x} emissions goals. Design requirements for the air injection system for the Marion boiler were developed using FLUENT, a commercially available computational fluid dynamics (CFD) code. A series of runs were made to obtain a design for final air injection that met the process design goals as closely as possible.

  19. Theoretical investigation of stabilities and optical properties of Si{sub 12}C{sub 12} clusters

    SciTech Connect (OSTI)

    Duan, Xiaofeng F.; Burggraf, Larry W.

    2015-01-21

    By sorting through hundreds of globally stable Si{sub 12}C{sub 12} isomers using a potential surface search and using simulated annealing, we have identified low-energy structures. Unlike isomers knit together by Si–C bonds, the lowest energy isomers have segregated carbon and silicon regions that maximize stronger C–C bonding. Positing that charge separation between the carbon and silicon regions would produce interesting optical absorption in these cluster molecules, we used time-dependent density functional theory to compare the calculated optical properties of four isomers representing structural classes having different types of silicon and carbon segregation regions. Absorptions involving charge transfer between segregated carbon and silicon regions produce lower excitation energies than do structures having alternating Si–C bonding for which frontier orbital charge transfer is exclusively from separated carbon atoms to silicon atoms. The most stable Si{sub 12}C{sub 12} isomer at temperatures below 1100 K is unique as regards its high symmetry and large optical oscillator strength in the visible blue. Its high-energy and low-energy visible transitions (1.15 eV and 2.56 eV) are nearly pure one-electron silicon-to-carbon transitions, while an intermediate energy transition (1.28 eV) is a nearly pure carbon-to-silicon one-electron charge transfer.

  20. Optically pumped cerium-doped LiSrAlF{sub 6} and LiCaAlF{sub 6}

    DOE Patents [OSTI]

    Marshall, C.D.; Payne, S.A.; Krupke, W.F.

    1996-05-14

    Ce{sup 3+}-doped LiSrAlF{sub 6} crystals are pumped by ultraviolet light which is polarized along the c axis of the crystals to effectively energize the laser system. In one embodiment, the polarized fourth harmonic light output from a conventional Nd:YAG laser operating at 266 nm is arranged to pump Ce:LiSrAlF{sub 6} with the pump light polarized along the c axis of the crystal. The Ce:LiSrAlF{sub 6} crystal may be placed in a laser cavity for generating tunable coherent ultraviolet radiation in the range of 280-320 nm. Additionally, Ce-doped crystals possessing the LiSrAlF{sub 6} type of chemical formula, e.g. Ce-doped LiCaAlF{sub 6} and LiSrGaF{sub 6}, can be used. Alternative pump sources include an ultraviolet-capable krypton or argon laser, or ultraviolet emitting flashlamps. The polarization of the pump light will impact operation. The laser system will operate efficiently when light in the 280-320 nm gain region is injected or recirculated in the system such that the beam is also polarized along the c axis of the crystal. The Ce:LiSrAlF{sub 6} laser system can be configured to generate ultrashort pulses, and it may be used to pump other devices, such as an optical parametric oscillator. 10 figs.

  1. Optically pumped cerium-doped LiSrAlF.sub.6 and LiCaAlF.sub.6

    DOE Patents [OSTI]

    Marshall, Christopher D.; Payne, Stephen A.; Krupke, William F.

    1996-01-01

    Ce.sup.3+ -doped LiSrAlF.sub.6 crystals are pumped by ultraviolet light which is polarized along the c axis of the crystals to effectively energize the laser system. In one embodiment, the polarized fourth harmonic light output from a conventional Nd:YAG laser operating at 266 nm is arranged to pump Ce:LiSrAlF.sub.6 with the pump light polarized along the c axis of the crystal. The Ce:LiSrAlF.sub.6 crystal may be placed in a laser cavity for generating tunable coherent ultraviolet radiation in the range of 280-320 nm. Additionally, Ce-doped crystals possessing the LiSrAlF.sub.6 type of chemical formula, e.g. Ce-doped LiCaAlF.sub.6 and LiSrGaF.sub.6, can be used. Alternative pump sources include an ultraviolet-capable krypton or argon laser, or ultraviolet emitting flashlamps. The polarization of the pump light will impact operation. The laser system will operate efficiently when light in the 280-320 nm gain region is injected or recirculated in the system such that the beam is also polarized along the c axis of the crystal. The Ce:LiSrAlF.sub.6 laser system can be configured to generate ultrashort pulses, and it may be used to pump other devices, such as an optical parametric oscillator.

  2. Bifunctional Fe{sub 3}O{sub 4}@Gd{sub 2}O{sub 3}:Eu{sup 3+}nanocomposites obtained by the homogeneous precipitation method

    SciTech Connect (OSTI)

    Peng, Hongxia; Cui, Bin; Wang, Yingsai

    2013-05-15

    Graphical abstract: The TEM images reveal clearly the coreshell structures because of the obvious difference in contrast between the central part and the fringe, which indicates the Gd{sub 2}O{sub 3}:Eu{sup 3+} layer had successfully deposited on the magnetite Fe{sub 3}O{sub 4} cores. And Fe{sub 3}O{sub 4}@Gd{sub 2}O{sub 3}:Eu{sup 3+} nanoparticles keep the spherical morphology, non-aggregation and rough surface. The images reveal that the average diameters of the Fe{sub 3}O{sub 4} and Fe{sub 3}O{sub 4}@Gd{sub 2}O{sub 3}:Eu{sup 3+} nanoparticles are ?200 nm and ?250 nm, respectively. The thickness of Gd{sub 2}O{sub 3}:Eu{sup 3+} layer is ?25 nm. Highlights: ? Fe{sub 3}O{sub 4}@Gd{sub 2}O{sub 3}:Eu{sup 3+} nanocomposites were synthesized by homogeneous precipitation method. ? Formation of coreshell nanostructure revealed by transmission electron microscopy. ? Fe{sub 3}O{sub 4}@Gd{sub 2}O{sub 3}:Eu{sup 3+} nanocomposites showed magnetic behavior and fluorescence properties. ? Possible applications including bioseparation, drug delivery system, bio-labels, etc. - Abstract: An easy homogeneous precipitation method was developed for the synthesis of bifunctional magnetic-fluorescent nanocomposites with Fe{sub 3}O{sub 4} nanoparticles as the core and europium-doped gadolinium oxide (Gd{sub 2}O{sub 3}:Eu{sup 3+}) as the shell. The nanocomposites showed both strong magnetic behavior and unique Eu-related fluorescence properties with a high emission intensity, which may lead to development of nanocomposites with great potential for applications in drug targeting, biosensors, and diagnostic analysis.

  3. Crystal structure of Sr{sub 3}Ir{sub 2}O{sub 7} investigated by

    Office of Scientific and Technical Information (OSTI)

    transmission electron microscopy (Journal Article) | SciTech Connect structure of Sr{sub 3}Ir{sub 2}O{sub 7} investigated by transmission electron microscopy Citation Details In-Document Search Title: Crystal structure of Sr{sub 3}Ir{sub 2}O{sub 7} investigated by transmission electron microscopy We report on the crystallographic structure of the layered perovskite iridate Sr{sub 3}Ir{sub 2}O{sub 7}, investigated using transmission electron microscopy. The space group was found to be Bbcb

  4. Anisotropic magnetic properties of Dy{sub 6}Cr{sub 4}Al{sub 43} single

    Office of Scientific and Technical Information (OSTI)

    crystal (Journal Article) | SciTech Connect Anisotropic magnetic properties of Dy{sub 6}Cr{sub 4}Al{sub 43} single crystal Citation Details In-Document Search Title: Anisotropic magnetic properties of Dy{sub 6}Cr{sub 4}Al{sub 43} single crystal We have studied the anisotropic magnetic behavior of the rare earth intermetallic compound Dy{sub 6}Cr{sub 4}Al{sub 43}. This compound crystallizes in the hexagonal symmetry and orders ferromagnetically at 8.3 K as confirmed by the magnetic

  5. Investigating the reversibility of structural modifications of Li<sub>xsub>Ni<sub>yMnzCo>1-y-zsub>O₂ cathode materials during initial charge/discharge, at multiple length scales

    SciTech Connect (OSTI)

    Hwang, Sooyeon; Bak, Seong -Min; Kim, Seung Min; Chung, Kyung Yoon; Chang, Wonyoung

    2015-08-11

    In this work, we investigate the structural modifications occurring at the bulk, subsurface, and surface scales of Li<sub>xsub>Ni<sub>yMnzCo>1-y-zsub>O₂ (NMC; y, z = 0.8, 0.1 and 0.4, 0.3, respectively) cathode materials during the initial charge/discharge. Various analytical tools, such as X-ray diffraction, selected-area electron diffraction, electron energy-loss spectroscopy, and high-resolution electron microscopy, are used to examine the structural properties of the NMC cathode materials at the three different scales. Cut-off voltages of 4.3 and 4.8 V are applied during the electrochemical tests as the normal and extreme conditions, respectively. The high-Ni-content NMC cathode materials exhibit unusual behaviors, which is deviate from the general redox reactions during the charge or discharge. The transition metal (TM) ions in the high-Ni-content NMC cathode materials, which are mostly Ni ions, are reduced at 4.8 V, even though TMs are usually oxidized to maintain charge neutrality upon the removal of Li. It was found that any changes in the crystallographic and electronic structures are mostly reversible down to the sub-surface scale, despite the unexpected reduction of Ni ions. However, after the discharge, traces of the phase transitions remain at the edges of the NMC cathode materials at the scale of a few nanometers (i.e., surface scale). This study demonstrates that the structural modifications in NMC cathode materials are induced by charge as well as discharge at multiple length scales. These changes are nearly reversible after the first cycle, except at the edges of the samples, which should be avoided because these highly localized changes can initiate battery degradation.

  6. Method for making graded I-III-VI.sub.2 semiconductors and solar cell obtained thereby

    DOE Patents [OSTI]

    Devaney, Walter E.

    1987-08-04

    Improved cell photovoltaic conversion efficiencies are obtained by the simultaneous elemental reactive evaporation process of Mickelsen and Chen for making semiconductors by closer control of the evaporation rates and substrate temperature during formation of the near contact, bulk, and near junction regions of a graded I-III-VI.sub.2, thin film, semiconductor, such as CuInSe.sub.2 /(Zn,Cd)S or another I-III-VI.sub.2 /II-VI heterojunction.

  7. Influence of Sn on the thermoelectric properties of (Bi{sub x}Sb{sub 1-x}){sub 2}Te{sub 3} single crystals

    SciTech Connect (OSTI)

    Kulbachinskii, V.A.; Kytin, V.G.; Kudryashov, A.A.; Lunin, R.A.

    2012-09-15

    The influence of tin on the thermoelectric properties of p-(Bi{sub x}Sb{sub 1-x}){sub 2}Te{sub 3} single crystals (x=0; 0.25; 0.5) has been investigated. The temperature dependence of the Seebeck coefficient S, the electrical conductivity {sigma}, the heat conductivity k and the thermoelectric figure of merit of p-(Bi{sub x}Sb{sub 1-x}){sub 2}Te{sub 3} single crystals were measured in the temperature range 7-300 K. By an increase the Sn content, the hole concentration increases in p-(Bi{sub x}Sb{sub 1-x}){sub 2-y}Sn{sub y}Te{sub 3}. The heat conductivity k of the p-(Bi{sub x}Sb{sub 1-x}){sub 2-y}Sn{sub y}Te{sub 3} crystals decreases due to the Sn doping, while the electrical conductivity {sigma} increases in the temperature interval about 200sub x}Sb{sub 1-x}){sub 2}Te{sub 3} single crystals (x=0; 0.25; 0.5) has been investigated. Temperature dependence of Seebeck coefficient S, electrical conductivity {sigma}, thermal conductivity k and figure of merit of p-(Bi{sub x}Sb{sub 1-x}){sub 2}Te{sub 3} single crystals were measured in the temperature range 7-300 K. Electrical conductivity increases in the temperature interval 150Ksub x}Sb{sub 1-x}){sub 2}Te{sub 3} as shown in figure. By increasing the Sn content, the hole concentration increases in p-(Bi{sub x}Sb{sub 1-x}){sub 2-y}Sn{sub y}Te{sub 3}. The thermal conductivity k of the p-(Bi{sub x}Sb{sub 1-x}){sub 2-y}Sn{sub y}Te{sub 3} crystals decreases due to Sn doping. The Seebeck coefficient S for all compositions is positive and decreases due to Sn doping in the whole temperature range due to increase of the hole concentration under Sn doping. Highlights: Black-Right-Pointing-Pointer thermoelectric figure of merit for p-(Bi{sub x}Sb{sub 1-x}){sub 2}Te{sub 3} investigated at 7-300 K. Black-Right-Pointing-Pointer preferential scattering is ionized impurity scattering in Sn doped samples. Black-Right-Pointing-Pointer electrical conductivity increases at 150 Ksub x}Sb{sub 1-x}){sub 2-y}Sn{sub y}Te{sub 3} with Sn doping. Black-Right-Pointing-Pointer the thermal conductivity of (Bi{sub x}Sb{sub 1-x}){sub 2-y}Sn{sub y}Te{sub 3} decreases due to Sn doping.

  8. DETECTIONS OF C{sub 2}H, CYCLIC-C{sub 3}H{sub 2}, AND H{sup 13}CN IN NGC 1068

    SciTech Connect (OSTI)

    Nakajima, T.; Takano, S.; Kohno, K.; Inoue, H.

    2011-02-20

    We used the Nobeyama 45 m telescope to conduct a spectral line survey in the 3 mm band (85.1-98.4 GHz) toward one of the nearest galaxies with an active galactic nucleus (AGN), NGC 1068, and the prototypical starburst galaxy NGC 253. The beam size of this telescope is {approx} 18'', which was sufficient to spatially separate the nuclear molecular emission from the emission of the circumnuclear starburst region in NGC 1068. We detected rotational transitions of C{sub 2}H, cyclic-C{sub 3}H{sub 2}, and H{sup 13}CN in NGC 1068. These are detections of carbon-chain and carbon-ring molecules in NGC 1068. In addition, the C{sub 2}H N = 1-0 lines were detected in NGC 253. The column densities of C{sub 2}H were determined to be 3.4 x 10{sup 15} cm{sup -2} in NGC 1068 and 1.8 x 10{sup 15} cm{sup -2} in NGC 253. The column densities of cyclic-C{sub 3}H{sub 2} were determined to be 1.7 x 10{sup 13} cm{sup -2} in NGC 1068 and 4.4 x 10{sup 13} cm{sup -2} in NGC 253. We calculated the abundances of these molecules relative to CS for both NGC 1068 and NGC 253, and found that there were no significant differences in the abundances between the two galaxies. This result suggests that the basic carbon-containing molecules are either insusceptible to AGN or are tracing cold (T{sub rot} {approx} 10 K) molecular gas rather than X-ray irradiated hot gas.

  9. Regional Education Partners

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Regional Education Partners Regional Education Partners One of the Laboratory's STEM education objectives is centered on strengthening the future workforce of Northern New Mexico...

  10. UFe/sub 4/P/sub 12/ and CeFe/sub 4/P/sub 12/: non-metallic isotypes of superconducting LaFe/sub 4/P/sub 12/

    SciTech Connect (OSTI)

    Meisner, G.P.; Torikachvili, M.S.; Yang, K.N.; Maple, M.B.; Guertin, R.P.

    1984-01-01

    The new compound UFe/sub 4/P/sub 12/, which was found to be isostructural to superconducting LaFe/sub 4/P/sub 12/ and with a lattive constant of 7.7729 A, is a semiconductor and shows ferromagnetic order below 3.15 K. CeFe/sub 4/P/sub 12/ is also a semiconductor and its magnetic susceptibility is unusually small in comparison to LaFe/sub 4/P/sub 12/. The semiconducting behaviors of both UFe/sub 4/P/sub 12/ and CeFe/sub 4/P/sub 12/ seem anomalous and may arise from strong f-electron hybridization.

  11. UFe/sub 4/P/sub 12/ and CeFe/sub 4/P/sub 12/: Nonmetallic isotypes of superconducting LaFe/sub 4/P/sub 12/

    SciTech Connect (OSTI)

    Meisner, G.P.; Torikachvili, M.S.; Yang, K.N.; Maple, M.B.; Guertin, R.P.

    1985-04-15

    The new compound UFe/sub 4/P/sub 12/, which was found to be isostructural to superconducting LaFe/sub 4/P/sub 12/ and have a lattice constant of 7.7729 A, is a semiconductor and shows ferromagnetic order below 3.15 K. CeFe/sub 4/P/sub 12/ is also a semiconductor, and its magnetic susceptibility is unusually small in comparison to LaFe/sub 4/P/sub 12/. The semiconducting behaviors of both UFe/sub 4/P/sub 12/ and CeFe/sub 4/P/sub 12/ seem anomalous and may arise from strong f-electron hybridization.

  12. Phase diagram and magnetocaloric effects in Ni{sub 50}Mn{sub 35}(In{sub 1?x}Cr{sub x}){sub 15} and (Mn{sub 1?x}Cr{sub x})NiGe{sub 1.05} alloys

    SciTech Connect (OSTI)

    Quetz, Abdiel Muchharla, Baleeswaraiah; Dubenko, Igor; Talapatra, Saikat; Ali, Naushad; Samanta, Tapas; Stadler, Shane

    2014-05-07

    The magnetocaloric and thermomagnetic properties of Ni{sub 50}Mn{sub 35}(In{sub 1?x}Cr{sub x}){sub 15} and (Mn{sub 1?x}Cr{sub x}) NiGe{sub 1.05} systems for 0???x???0.105 and 0???x???0.1, respectively, have been studied by x-ray diffraction, differential scanning calorimetry, and magnetization measurements. Partial substitution of Cr for Mn in (Mn{sub 1?x}Cr{sub x})NiGe{sub 1.05} results in a first order magnetostructural transition from a hexagonal paramagnetic to an orthorhombic paramagnetic phase near T{sub M}???380?K (for x?=?0.07). Partial substitution of Cr for In in Ni{sub 50}Mn{sub 35}(In{sub 1?x}Cr{sub x}){sub 15} shifts the magnetostructural transition to a higher temperature (T?=?T{sub M}???450?K) for x?=?0.1. Large magnetic entropy changes of ?S?=??12 (J/(kgK)) and ?S?=??11 (J/(kgK)), both for a magnetic field change of 5?T, were observed in the vicinity of T{sub M} for (Mn{sub 1?x}Cr{sub x})NiGe{sub 1.05} and Ni{sub 50}Mn{sub 35}(In{sub 1?x}Cr{sub x}){sub 15}, respectively.

  13. Eliminating Voltage Decay of Lithium-Rich Li<sub>1.14sub>Mn>0.54sub>Ni>0.14sub>Co>0.14sub>O>2sub> Cathodes by Controlling the Electrochemical Process

    SciTech Connect (OSTI)

    Wei, Z.; Zhu, Y.; Zhang, W.; Wang, F.; Zhang, Q.; Qiu, B.; Han, S.; Xia, Y.; Liu, Z.

    2015-03-27

    Lithium-rich material owns a particularly high capacity owing to the activation of electrochemical inactive Li<sub>2sub>MnO>3sub> phase. But at the same time, MnO<sub>2sub> phase formed after Li<sub>2sub>MnO>3sub> activation confronts a severe problem of converting to spinel phase, and resulting in voltage decay. To our knowledge, this phenomenon is inherent property of layered manganese oxide materials and can hardly be overcome. Based on this, unlike previous reports, herein we design a method for the first time to accelerate the phase transformation by tuning the charge upper-limit voltage at a high value, so the phase transformation process can be finished in a few cycles. Then material structure remains stable while cycling at a low upper-limit voltage. By this novel method voltage decay is eliminated significantly.

  14. Field-dependent magnetization of BiFeO<sub>3sub> in ultrathin La<sub>0.7sub>Sr>0.3sub>MnO>3sub>/BiFeO>3sub> superlattice

    SciTech Connect (OSTI)

    Fitzsimmons, Michael R.; Jia, Quanxi X.; Singh, Surendra; Chen, A. P.; Xiong, J.

    2015-12-02

    We report the observation of field-induced magnetization of BiFeO<sub>3sub> (BFO) in an ultrathin La<sub>0.7sub>Sr>0.3sub>MnO>3sub> (LSMO)/BFO superlattice using polarized neutron reflectivity (PNR). The depth dependent structure and magnetic characterization of subnano layer thick (thickness ~ 0.7 nm each) LSMO/BFO hetrostructure is carried out using X-ray reflectivity and PNR techniques. Our PNR results indicate parallel alignment of magnetization as well as enhancement in magnetic moment across LSMO/BFO interfaces. The study showed an increase in average magnetization on increasing applied magnetic field at 10K. As a result, we observed a saturation magnetization of 110 ± 15 kA/m (~0.8 μ<sub>B>/Fe) for ultrathin BFO layer (~2 unit cell) sandwiched between ultrathin LSMO layers (~ 2 unit cell).

  15. UF{sub 6} pressure excursions during cylinder heating

    SciTech Connect (OSTI)

    Brown, P.G.

    1991-12-31

    As liquid UF{sub 6} inside a cylinder changes from a liquid to a solid, it forms a porous solid which occupies approximately the same volume as that of the liquid before cooling. Simultaneously as the liquid cools, UF{sub 6} vapor in the cylinder ullage above the liquid desublimes on the upper region of the inner cylinder wall. This solid is a dense, glass-like material which can accumulate to a significant thickness. The thickness of the solid coating on the upper cylinder wall and directly behind the cylinder valve area will vary depending on the conditions during the cooling stage. The amount of time lapsed between UF{sub 6} solidification and UF{sub 6} liquefaction can also affect the UF{sub 6} coating. This is due to the daily ambient heat cycle causing the coating to sublime from the cylinder wall to cooler areas, thus decreasing the thickness. Structural weakening of the dense UF{sub 6} layer also occurs due to cylinder transport vibration and thermal expansion. During cylinder heating, the UF{sub 6} nearest the cylinder wall will liquefy first. As the solid coating behind the cylinder valve begins to liquefy, it results in increased pressure depending upon the available volume for expansion. At the Paducah Gaseous Diffusion Plant (PGDP) during the liquefaction of the UF{sub 6} in cylinders in the UF{sub 6} feed and sampling autoclaves, this pressure increase has resulted in the activation of the systems rupture discs which are rated at 100 pounds per square inch differential.

  16. Table 3. Estimation Results for National and Sub-PAD District...

    U.S. Energy Information Administration (EIA) Indexed Site

    Estimation Results for National and Sub-PAD District Regions Dependent Variable: D(RETUS) Dependent Variable: D(RETPAD1X) Dependent Variable: D(RETPAD1Y) Dependent Variable:...

  17. Simple and low-temperature preparation of Co{sub 3}O{sub 4} sphere-like nanoparticles via solid-state thermolysis of the [Co(NH{sub 3}){sub 6}](NO{sub 3}){sub 3} complex

    SciTech Connect (OSTI)

    Farhadi, Saeid; Pourzare, Kolsoum

    2012-06-15

    Highlights: ? [Co(NH{sub 3}){sub 6}](NO{sub 3}){sub 3} precursor was used for synthesizing pure Co{sub 3}O{sub 4} nanocrystals. ? Co{sub 3}O{sub 4} nanocrystals were synthesized at low temperature of 200 C. ? Co{sub 3}O{sub 4} nanocrystals show a weak ferromagnetic behavior at room temperature. ? This simple method is low-cost and suitable for high-scale production of Co{sub 3}O{sub 4}. -- Abstract: In this work, spinel-type Co{sub 3}O{sub 4} spherical nanoparticles were easily prepared via decomposition of the hexamminecobalt(III) nitrate complex, [Co(NH{sub 3}){sub 6}](NO{sub 3}){sub 3}, at low temperature (200 C). The product was characterized by thermal analysis (TGA/DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, UVvis spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), BrunauerEmmettTeller (BET) specific surface area measurement and magnetic measurements. The results confirmed that pure single-phase Co{sub 3}O{sub 4} nanoparticles with weak ferromagnetic behavior were obtained by this method. TEM images showed that the Co{sub 3}O{sub 4} nanoparticles are sphere-like with an average diameter size of around 15 nm. The optical spectrum indicated two direct band gaps at 2.15 and 3.56 eV which are blue-shifted relative to reported values for the bulk sample. Using this fast and simple method, Co{sub 3}O{sub 4} nanoparticles can be produced without expensive and toxic solvents or complicated equipment.

  18. A novel organic–inorganic hybrid with Anderson type polyanions as building blocks: (C{sub 6}H{sub 10}N{sub 3}O{sub 2}){sub 2}Na(H{sub 2}O){sub 2}[Al(OH){sub 6}Mo{sub 6}O{sub 18}]·6H{sub 2}O

    SciTech Connect (OSTI)

    Thabet, Safa; Ayed, Brahim; Haddad, Amor

    2012-11-15

    Graphical abstract: Display Omitted Highlights: ► Synthesis of a novel inorganic–organic hybrid compound based on Anderson polyoxomolybdates. ► Characterization by X-ray diffraction, IR and UV–Vis spectroscopies of the new compound. ► Potential applications in catalysis, biochemical analysis and electrical conductivity of the organic–inorganic compound. -- Abstract: A new organic–inorganic hybrid compound based on Anderson polyoxomolybdates, (C{sub 6}H{sub 10}N{sub 3}O{sub 2}){sub 2}Na(H{sub 2}O){sub 2}[Al(OH){sub 6}Mo{sub 6}O{sub 18}]·6H{sub 2}O (1) have been isolated by the conventional solution method and characterized by single-crystal X-ray diffraction, infrared, ultraviolet spectroscopy and Thermogravimetric Analysis (TGA). This compound crystallized in the triclinic system, space group P−1, with a = 94.635(1) Å, b = 10.958(1) Å, c = 11.602(1) Å, α = 67.525(1)°, β = 71.049(1)°, γ = 70.124(1)° and Z = 1. The crystal structures of the compounds exhibit three-dimensional supramolecular assembly based on the extensive hydrogen bonding interactions between organic cations, sodium cations, water molecules and Anderson polyoxoanions. The infrared spectrum fully confirms the X-ray crystal structure and the UV spectrum of the title compound exhibits an absorption peak at 210 nm.

  19. Kondo Lattice Behavior in the Ordered Dilute Magnetic Semiconductor Yb<sub>14-xsub>LaxMnSb>11sub>

    SciTech Connect (OSTI)

    Sales, Brian C; Khalifah, Peter; Enck, Thomas P; Nagler, Evan J; Sykora, Richard E; Jin, Rongying; Mandrus, David

    2005-01-01

    We report Hall, magnetic, heat capacity, and doping studies from single crystals of Yb{sub 14}MnSb{sub 11} and Yb{sub 13.3}La{sub 0.7}MnSb{sub 11}. These heavily doped semiconducting compounds are ferromagnetic below 53 and 39 K, respectively. The renormalization of the carrier mass from 2m{sub 3} near room temperature to 20m{sub e} at 5 K, plus the magnetic evidence for partial screening of the Mn magnetic moments suggest that these compounds represent rare examples of an underscreened Kondo lattice with T{sub K} {approx} 285 K.

  20. Electron-hole diffusion lengths >175 μm in solution-grown CH<sub>3sub>NH>3sub>PbI>3sub> single crystals

    SciTech Connect (OSTI)

    Dong, Qingfeng; Fang, Yanjun; Shao, Yuchuan; Mulligan, Padhraic; Qiu, Jie; Cao, Lei; Huang, Jinsong

    2015-02-27

    Long, balanced electron and hole diffusion lengths greater than 100 nanometers in the polycrystalline organolead trihalide compound CH<sub>3sub>NH>3sub>PbI>3sub> are critical for highly efficient perovskite solar cells. We found that the diffusion lengths in CH<sub>3sub>NH>3sub>PbI>3sub> single crystals grown by a solution-growth method can exceed 175 micrometers under 1 sun (100 mW cm–2) illumination and exceed 3 millimeters under weak light for both electrons and holes. The internal quantum efficiencies approach 100% in 3-millimeter-thick single-crystal perovskite solar cells under weak light. These long diffusion lengths result from greater carrier mobility, longer lifetime, and much smaller trap densities in the single crystals than in polycrystalline thin films. As a result, the long carrier diffusion lengths enabled the use of CH<sub>3sub>NH>3sub>PbI>3sub> in radiation sensing and energy harvesting through the gammavoltaic effect, with an efficiency of 3.9% measured with an intense cesium-137 source.

  1. Λ<sub>b→pl⁻ν¯l> form factors from lattice QCD with static b quarks

    SciTech Connect (OSTI)

    Detmold, William; Lin, C.-J. David; Meinel, Stefan; Wingate, Matthew

    2013-07-23

    We present a lattice QCD calculation of form factors for the decay Λ<sub>bsub>→pμ⁻ν¯μ>, which is a promising channel for determining the Cabibbo-Kobayashi-Maskawa matrix element |V<sub>ub>| at the Large Hadron Collider. In this initial study we work in the limit of static b quarks, where the number of independent form factors reduces to two. We use dynamical domain-wall fermions for the light quarks, and perform the calculation at two different lattice spacings and at multiple values of the light-quark masses in a single large volume. Using our form factor results, we calculate the Λ<sub>bsub>→pμ⁻ν¯μ> differential decay rate in the range 14 GeV²≤q²≤q²<sub>max>, and obtain the integral ∫q²<sub>max> <sub>14 GeV²sub>[dΓ/dq²]dq²/|V<sub>ub>|²=15.3±4.2 ps⁻¹. Combined with future experimental data, this will give a novel determination of |V<sub>ub>| with about 15% theoretical uncertainty. The uncertainty is dominated by the use of the static approximation for the b quark, and can be reduced further by performing the lattice calculation with a more sophisticated heavy-quark action.

  2. Visible Light Photoreduction of CO<sub>2sub> Using CdSe/Pt/TiO<sub>2sub> Heterostructured Catalysts

    SciTech Connect (OSTI)

    Wang, Congjun; Thompson, Robert L.; Baltrus, John; Matranga, Christopher

    2010-01-07

    A series of CdSe quantum dot (QD)-sensitized TiO<sub>2sub> heterostructures have been synthesized, characterized, and tested for the photocatalytic reduction of CO<sub>2sub> in the presence of H<sub>2sub>O. Our results show that these heterostructuredmaterials are capable of catalyzing the photoreduction of CO<sub>2sub> using visible light illumination (? > 420 nm) only. The effect of removing surfactant caps from the CdSe QDs by annealing and using a hydrazine chemical treatment have also been investigated. The photocatalytic reduction process is followed using infrared spectroscopy to probe the gas-phase reactants and gas chromatography to detect the products. Gas chromatographic analysis shows that the primary reaction product is CH<sub>4sub>, with CH<sub>3sub>OH, H<sub>2sub>, and CO observed as secondary products. Typical yields of the gas-phase products after visible light illumination (? > 420 nm) were 48 ppm g-1 h-1 of CH<sub>4sub>, 3.3 ppm g-1 h-1 of CH<sub>3sub>OH (vapor), and trace amounts of CO and H<sub>2.sub>

  3. Exchange bias effect in Au-Fe<sub>3sub>O>4sub> dumbbell nanoparticles induced by the charge transfer from gold

    SciTech Connect (OSTI)

    Feygenson, Mikhail; Bauer, John C; Gai, Zheng; Marques, Carlos; Aronson, Meigan C.; Teng, Xiaowei; Su, Dong; Stanic, Vesna; Urban, Volker S; Kevin, Beyer; Dai, Sheng

    2015-08-10

    We have studied the origin of the exchange bias effect in the Au-Fe<sub>3sub>O>4sub> dumbbell nanoparticles in two samples with different sizes of the Au seed nanoparticles (4.1 and 2.7 nm) and same size of Fe<sub>3sub>O>4sub> nanoparticles (9.8 nm). The magnetization, small-angle neutron scattering, synchrotron x-ray diffraction and scanning transmission electron microscope measurements determined the antiferromagnetic FeO wstite phase within Fe<sub>3sub>O>4sub> nanoparticles, originating at the interface with the Au nanoparticles. The interface between antiferromagnetic FeO and ferrimagnetic Fe<sub>3sub>O>4sub> is giving rise to the exchange bias effect. The strength of the exchange bias fields depends on the interfacial area and lattice mismatch between both phases. We propose that the charge transfer from the Au nanoparticles is responsible for a partial reduction of the Fe<sub>3sub>O>4sub> into FeO phase at the interface with Au nanoparticles. The Au-O bonds are formed across the interface to accommodate an excess of oxygen released during the reduction of magnetite.

  4. Hydrogenation of CO<sub>2sub> to methanol: Importance of metal–oxide and metal–carbide interfaces in the activation of CO<sub>2sub>

    SciTech Connect (OSTI)

    Rodriguez, José A.; Liu, Ping; Stacchiola, Dario J.; Senanayake, Sanjaya D.; White, Michael G.; Chen, Jingguang G.

    2015-09-30

    In this study, the high thermochemical stability of CO<sub>2sub> makes it very difficult to achieve the catalytic conversion of the molecule into alcohols or other hydrocarbon compounds, which can be used as fuels or the starting point for the generation of fine chemicals. Pure metals and bimetallic systems used for the CO<sub>2sub> → CH<sub>3sub>OH conversion usually bind CO<sub>2sub> too weakly and, thus, show low catalytic activity. Here, we discuss a series of recent studies that illustrate the advantages of metal–oxide and metal–carbide interfaces when aiming at the conversion of CO2 into methanol. CeO<sub>x>/Cu(111), Cu/CeO<sub>x/TiO>2sub>(110), and Au/CeO<sub>x/TiO>2sub>(110) exhibit an activity for the CO<sub>2sub> → CH<sub>3sub>OH conversion that is 2–3 orders of magnitude higher than that of a benchmark Cu(111) catalyst. In the Cu–ceria and Au–ceria interfaces, the multifunctional combination of metal and oxide centers leads to complementary chemical properties that open active reaction pathways for methanol synthesis. Efficient catalysts are also generated after depositing Cu and Au on TiC(001). In these cases, strong metal–support interactions modify the electronic properties of the admetals and make them active for the binding of CO<sub>2sub> and its subsequent transformation into CH<sub>3sub>OH at the metal–carbide interfaces.

  5. Millimeter size single crystals of superconducting YBa[sub 2]Cu[sub 3]O[sub x

    DOE Patents [OSTI]

    Damento, M.A.; Gschneidner, K.A. Jr.

    1989-04-25

    A method of growing large, up to 1 mm size single crystals of superconducting YBa[sub 2]Cu[sub 3]O[sub x], wherein x equals from 6.5 to 7.2 is disclosed.

  6. The equilibrium vortex melting transition in YBa{sub 2}Cu{sub 3}O{sub 7}

    SciTech Connect (OSTI)

    Crabtree, G.W.; Welp, U.; Kwok, W.K.; Fendrich, J.A.; Veal, B.W.

    1996-10-01

    The dynamic and thermodynamic experimental evidence supporting first order vortex melting in clean crystals of YBa{sub 2}Cu{sub 3}O{sub 7} is reviewed.

  7. Phonon and magnon scattering of Bi{sub 2}Fe{sub 4}O{sub 9} ceramic

    SciTech Connect (OSTI)

    Sharma, Poorva E-mail: vdinesh33@rediffmail.com; Kumar, Ashwini E-mail: vdinesh33@rediffmail.com; Varshney, Dinesh E-mail: vdinesh33@rediffmail.com

    2014-04-24

    We report the phonon structure of Bi{sub 2}Fe{sub 4}O{sub 9} ceramics as synthesized by solid-state reaction route. Rietveld refined X-ray diffraction patterns confirmed the formation of single-phase perovskite structure and all the peaks of Bi{sub 2}Fe{sub 4}O{sub 9} perfectly indexed to the orthorhombic (space group Pbam). Raman scattering measurements identifies 12A{sub g}+1B{sub 2g}+1B{sub 3g} Raman active optical phonon modes. Apart from phonon scattering, mode at 470 cm{sup ?1} is observed which is due to magnon scattering. The P-E loop infers paraelectric nature of Bi{sub 2}Fe{sub 4}O{sub 9}.

  8. Millimeter size single crystals of superconducting YBa.sub.2 Cu.sub.3 O.sub .

    DOE Patents [OSTI]

    Damento, Michael A. (Ames, IA); Gschneidner, Jr., Karl A. (Ames, IA)

    1989-04-25

    A method of growing large, up to 1 mm size single crystals of superconducting YBa.sub.2 Cu.sub.3 O.sub.x, wherein x equals from 6.5 to 7.2.

  9. Synthesis, crystal structure and magnetic properties of Li{sub 0.44}Eu{sub 3}[B{sub 3}N{sub 6}

    SciTech Connect (OSTI)

    Kokal, I.; Aydemir, U.; Prots, Yu.; Frster, T.; Sichelschmidt, J.; Yahyaoglu, M.; Auffermann, G.; Schnelle, W.; Schappacher, F.; Pttgen, R.; Somer, M.

    2014-02-15

    Li{sub 0.44}Eu{sub 3}[B{sub 3}N{sub 6}] was synthesized from the metathesis reaction of Li{sub 3}[BN{sub 2}] and EuCl{sub 3} at 850 C. Li{sub 0.44}Eu{sub 3}[B{sub 3}N{sub 6}] crystallizes in the trigonal space group R3{sup }c (No. 167) with a=12.0225(2) , c=6.8556(2) and Z=6. In the crystal structure, isolated, planar cyclic [B{sub 3}N{sub 6}]{sup 9?} units are charge-balanced by the mixed-valence Eu{sup 3+}/Eu{sup 2+} and Li{sup +} cations. Li{sup +} occupies partially (44%) the Wyckoff site 6b and is sandwiched between the [B{sub 3}N{sub 6}]{sup 9?} anions. Mssbauer spectroscopy results show the resonance lines of Eu{sup 2+} and Eu{sup 3+}, respectively, indicating the heterogeneous mixed valency of the Eu atoms. X-Band ESR investigations between 5 and 300 K reveal an intense signal over the whole temperature range originating from Eu{sup 2+}. Magnetic susceptibility measurements indicate a CurieWeiss behavior with an experimental effective magnetic moment of ?{sub eff}=8.28 ?{sub B} per formula unit. - Graphical abstract: Single crystals of Li{sub 0.44}Eu{sub 3}[B{sub 3}N{sub 6}] was obtained from the metathesis reaction of Li{sub 3}[BN{sub 2}] and EuCl{sub 3.}{sup 151}Eu Mssbauer, ESR and magnetic susceptibility measurements reveal the heterogeneous mixed valency of the Eu atoms. Display Omitted - Highlights: Single crystals of Li{sub 0.44}Eu{sub 3}[B{sub 3}N{sub 6}] was obtained from the metathesis reaction of Li{sub 3}[BN{sub 2}] and EuCl{sub 3} at 850 C. Crystal structure is built up by isolated, planar cyclic [B{sub 3}N{sub 6}]{sup 9?} units which are surrounded by mixed valence Eu{sup 3+}/Eu{sup 2+}. Li{sup +} occupies partially (44%) the site 6b and is sandwiched between the [B{sub 3}N{sub 6}]{sup 9?} anions. The {sup 151}Eu Mssbauer spectroscopy, electron spin resonance spectroscopy and magnetic susceptibility measurements confirm the heterogeneous mixed valency of Eu.

  10. Electron attachment and ionization coefficients and electron drift velocities in BF/sub 3/ and SiF/sub 4/

    SciTech Connect (OSTI)

    Hunter, S.R.; Carter, J.G.; Christophorou, L.G.

    1989-03-01

    The drift velocity of electrons (w) in SiF/sub 4/ and BF/sub 3/ has been measured over the density-reduced electric field (E/N) range 0.5 x 10/sup -17/ V cm/sup 2/ less than or equal toE/Nless than or equal to300 x 10/sup -17/ V cm/sup 2/ using a pulsed Townsend experimental technique. The electron attachment (eta/N) and ionization (..cap alpha../N) coefficients have also been measured in SiF/sub 4/ and BF/sub 3/ over the E/N range 30 x 10/sup -17/ V cm/sup 2/ less than or equal toE/Nless than or equal to300 x 10/sup -17/ V cm/sup 2/ in the same experiment. The electron drift velocities in these two gases exhibit regions of negative differential conductivity (NDC) similar to but smaller in magnitude than those in CH/sub 4/ and CF/sub 4/ . The effective ionization coefficient (alpha-bar/N) has been obtained from the eta/N and ..cap alpha../N measurements in both gases, from which the high-voltage limiting electric field strengths (E/N)/sub lim/ have been found to be 123 x 10/sup -17/ V cm/sup 2/ for BF/sub 3/ and 121 x 10/sup -17/ V cm/sup 2/ for SiF/sub 4/. The significance of these results in modeling gas discharges for a number of technological applications is indicated.

  11. Generation of WO{sub 3}-ZrO{sub 2} catalysts from solid solutions of tungsten in zirconia

    SciTech Connect (OSTI)

    Cortes-Jacome, Maria A.; Angeles-Chavez, Carlos; Bokhimi, Xim; Toledo-Antonio, J.A. . E-mail: jtoledo@imp.mx

    2006-08-15

    WO{sub 3}-ZrO{sub 2} samples were obtained by precipitating zirconium oxynitrate in presence of WO{sub 4} {sup =} species in solution from ammonium metatungstate at pH=10.0. Samples were characterized by atomic absorption spectroscopy, thermal analysis, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and energy filtered-TEM. The ammonia retained in the dried sample produced a reductive atmosphere to generate W{sup 5+} ions coexisting with W{sup 6+} ions to produce a solid solution of tungsten in the zirconia lattice to stabilize the zirconia tetragonal phase when the sample was annealed at 560 deg. C. When the sample was annealed at 800 deg. C, the W atoms near crystallite surface were oxidized to W{sup 6+}, producing patches of WO{sub 3} on the zirconia crystallite. The HR-TEM analysis confirmed the existence of the solid solution when the sample was annealed at 560 deg. C, and two types of crystalline regions were identified: One with nearly spherical morphology, an average diameter of 8 nm and the atomic distribution of tetragonal zirconia. The second one had a non-spherical morphology with well-faceted faces and dimensions larger than 30 nm, and the atom distribution of tetragonal zirconia. When samples were annealed at 800 deg. C two different zirconia crystallites were formed: Those where only part of the dissolved tungsten atoms segregated to crystallite surface producing patches of nanocrystalline WO{sub 3} on the crystallite surface of tetragonal zirconia stabilized with tungsten. The second type corresponded to monoclinic zirconia crystallites with patches of nanocrystalline WO{sub 3} on their surface. The tungsten segregation gave rise to the WO{sub 3}-ZrO{sub 2} catalysts. - Graphical abstract: WO {sub x} -ZrO{sub 2} catalysts were obtained by precipitating zirconium oxynitrate in presence of WO{sub 4} {sup =}species. Initially, the W atoms remained inside the crystallite after annealing at 560 deg. C in a reduced oxidation state (W{sup 5+}), whereas, the sample annealed at 800 deg. C, the W atoms migrate from the bulk to the surface, forming a layer of W atoms on a ZrO{sub 2} core, with the consequent oxidation to W{sup 6+}, producing patches of nanocrystalline WO{sub 3} with dimension smaller than 3 nm.

  12. Synthesis, characterization and optical properties of NH{sub 4}Dy(PO{sub 3}){sub 4}

    SciTech Connect (OSTI)

    Chemingui, S.; Ferhi, M. Horchani-Naifer, K.; Férid, M.

    2014-09-15

    Polycrystalline powders of NH{sub 4}Dy(PO{sub 3}){sub 4} polyphosphate have been grown by the flux method. This compound was found to be isotopic with NH{sub 4}Ce(PO{sub 3}){sub 4} and RbHo(PO{sub 3}){sub 4}. It crystallizes in the monoclinic space group P2{sub 1/n} with unit cell parameters a=10.474(6) Å, b=9.011(4) Å, c=10.947(7) Å and β=106.64(3)°. The title compound has been transformed to triphosphate Dy(PO{sub 3}){sub 3} after calcination at 800 °C. Powder X-ray diffraction, infrared and Raman spectroscopies and the differential thermal analysis have been used to identify these materials. The spectroscopic properties have been investigated through absorption, excitation, emission spectra and decay curves of Dy{sup 3+} ion in both compounds at room temperature. The emission spectra show the characteristic emission bands of Dy{sup 3+} in the two compounds, before and after calcination. The integrated emission intensity ratios of the yellow to blue (I{sub Y}/I{sub B}) transitions and the chromaticity properties have been determined from emission spectra. The decay curves are found to be double-exponential. The non-exponential behavior of the decay rates was related to the resonant energy transfer as well as cross-relaxation between the donor and acceptor Dy{sup 3+} ions. The determined properties have been discussed as function of crystal structure of both compounds. They reveal that NH{sub 4}Dy(PO{sub 3}){sub 4} is promising for white light generation but Dy(PO{sub 3}){sub 3} is potential candidates in field emission display (FED) and plasma display panel (PDP) devices. - Graphical abstract: The CIE color coordinate diagrams showing the chromatic coordinates of Dy{sup 3+} luminescence in NH{sub 4}Dy(PO{sub 3}){sub 4} and Dy(PO{sub 3}){sub 3}. - Highlights: • The polycrystalline powders of NH{sub 4}Dy(PO{sub 3}){sub 4} and Dy(PO{sub 3}){sub 3} are synthesized. • The obtained powders are characterized. • The spectroscopic properties of Dy{sup 3+} ion are investigated. • Results are discussed as function of crystal structure and chemical composition. • The usefulness of NH{sub 4}Dy(PO{sub 3}){sub 4} and Dy(PO{sub 3}){sub 3} in optical devices is revealed.

  13. F region above kauai: Measurement, model, modification

    SciTech Connect (OSTI)

    Johnson, C.Y.; Sjolander, G.W.; Oran, E.S.; Young, T.R.; Bernhardt, P.A.; Da Rosa, A.V.

    1980-08-01

    A detailed description and analysis is presented of the Lagopedo II results. The rocket was launched on September 11, 1977. Prior to an explosive chemical release a rocket-borne ion mass spectrometer and dual-frequency beacon measured the ion composition and electron content of the undisturbed F region above Kauai, Hawaii. These results are compared to a detailed calculation of ionospheric ion denities. Considerable H/sub 2/O outgassing produced measurable 18/sup +/(H/sub 2/O/sup +/) and 19/sup +/(H/sub 3/O/sup +/) currents which together with O/sup +/ current were used to determine the H/sup 3/O/sup +//H/sub 2/O/sup +/ dissociative recombination rate ratio. The explosive event at 283 km swept clean a l-km-radius region. The boundary of the ionic void was characterized by a steep gradient in the ion density. Results for the first 60 s after the event are presented which show changes in ambient ion species 14/sup +/, 16/sup +/, 30/sup +/, new reactant species 15/sup +/, 17/sup +/, 18/sup +/, 19/sup +/, 27/sup +/, and 46/sup +/, and evidence of ionic depletion by sweeping.

  14. Palladium site ordering and the occurrence of superconductivity in Bi{sub 2}Pd{sub 3}Se{sub 2-x}S{sub x}

    SciTech Connect (OSTI)

    Weihrich, R.; Matar, S.F.; Anusca, I.; Pielnhofer, F.; Peter, P.; Bachhuber, F.; Eyert, V.

    2011-04-15

    The crystallographic and electronic structures of compounds related to parkerite (Bi{sub 2}Ni{sub 3}S{sub 2}) are investigated with respect to the recently reported occurrence (Bi{sub 2}Pd{sub 3}Se{sub 2}) and absence (Bi{sub 2}Pd{sub 3}S{sub 2}) of superconductivity. Similarities and differences of the crystal structures are discussed within the series of solid solutions Bi{sub 2}Pd{sub 3}S{sub 2-x}Se{sub x} from powder and single crystal diffraction data. From crystal structure refinements, the question of different structures and settings of parkerite is discussed. Similar and different 2D and 3D partial Pd-Ch (Ch=S, Se) structures are related to half antiperovskite ordering schemes. To investigate the relation of low dimensional structures and the occurrence of superconductivity, electronic structures are analyzed by scalar-relativistic DFT calculations, including site projected DOS, ECOV and Fermi surfaces. -- Graphical abstract: Structure relations for perovskite type BiPd{sub 3}C, BiPd{sub 3/2}Se and BiPd{sub 3/2}S. Display Omitted Research highlights: {yields} Merging crystallographic and electronic structures studies to understand chalcogenides related to parkerite (Bi{sub 2}Ni{sub 3}S{sub 2}). {yields} Investigation in view of recently reported occurrence (Bi{sub 2}Pd{sub 3}Se{sub 2}) and absence (Bi{sub 2}Pd{sub 3}S{sub 2}) of superconductivity. {yields} Relationship of half perovskites with perovskites.

  15. Structural and superconducting properties of La{sub 2{minus}x}R{sub

    Office of Scientific and Technical Information (OSTI)

    x}Ba{sub 2}Ca{sub y}Cu{sub 4+y}O{sub 10+{delta}} (R=Nd,Gd;y=2x) system (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Structural and superconducting properties of La{sub 2{minus}x}R{sub x}Ba{sub 2}Ca{sub y}Cu{sub 4+y}O{sub 10+{delta}} (R=Nd,Gd;y=2x) system Citation Details In-Document Search Title: Structural and superconducting properties of La{sub 2{minus}x}R{sub x}Ba{sub 2}Ca{sub y}Cu{sub 4+y}O{sub 10+{delta}} (R=Nd,Gd;y=2x) system A nonsuperconducting

  16. Downhole fluid injection systems, CO<sub>2sub> sequestration methods, and hydrocarbon material recovery methods

    DOE Patents [OSTI]

    Schaef, Herbert T.; McGrail, B. Peter

    2015-07-28

    Downhole fluid injection systems are provided that can include a first well extending into a geological formation, and a fluid injector assembly located within the well. The fluid injector assembly can be configured to inject a liquid CO<sub>2sub>/H>2sub>O-emulsion into the surrounding geological formation. CO<sub>2sub> sequestration methods are provided that can include exposing a geological formation to a liquid CO<sub>2sub>/H>2sub>O-emulsion to sequester at least a portion of the CO<sub>2sub> from the emulsion within the formation. Hydrocarbon material recovery methods are provided that can include exposing a liquid CO<sub>2sub>/H>2sub>O-emulsion to a geological formation having the hydrocarbon material therein. The methods can include recovering at least a portion of the hydrocarbon material from the formation.

  17. Method for preparation of textured YBa.sub.2 Cu.sub.3 O.sub.x superconductor

    DOE Patents [OSTI]

    Selvamanickam, Venkat; Goyal, Amit; Kroeger, Donald M.

    1998-01-01

    The present invention relate to textured YBa.sub.2 Cu.sub.3 O.sub.x (Y-123) superconductors and a process of preparing them by directional recrystallization of compacts fabricated from quenched YBCO powders at temperatures about 100.degree. C. below the peritectic temperature to provide a superconductor where more than 75% of the YBa.sub.2 Cu.sub.3 O.sub.x phase is obtained without any Y.sub.2 BaCuO.sub.5 .

  18. Quadruple-layered perovskite (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13}

    SciTech Connect (OSTI)

    Kitada, A.; Tsujimoto, Y.; Yamamoto, T. [Department of Energy and Hydrocarbon Chemistry, Faculty of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Kobayashi, Y. [Department of Energy and Hydrocarbon Chemistry, Faculty of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); Narumi, Y. [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 (Japan); Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai 980-8577 (Japan); Kindo, K. [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 (Japan); Aczel, A.A.; Luke, G.M. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada); Uemura, Y.J. [Department of Physics, Columbia University, New York, NY 10027 (United States); Kiuchi, Y.; Ueda, Y. [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 (Japan); Yoshimura, K. [Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Ajiro, Y. [Department of Energy and Hydrocarbon Chemistry, Faculty of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); Kageyama, H., E-mail: kage@scl.kyoto-u.ac.jp [Department of Energy and Hydrocarbon Chemistry, Faculty of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Institute for Integrated Cell-Material Sciences, Kyoto University, Sakyo, Kyoto 606-8501 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi 332-0012 (Japan)

    2012-01-15

    We will present the synthesis, structure and magnetic properties of a new quadruple-layered perovskite (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13}. Through a topotactic ion-exchange reaction with CuCl{sub 2}, the precursor RbCa{sub 2}NaNb{sub 4}O{sub 13} presumably having an incoherent octahederal tliting changes into (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13} with a 2a{sub p} Multiplication-Sign 2a{sub p} Multiplication-Sign 2c{sub p} superstructure (tetragonal; a=7.73232(5) A, c=39.2156(4) A). The well-defined superstructure for the ion-exchanged product should be stabilized by the inserted CuCl{sub 4}O{sub 2} octahedral layers that firmly connect with neighboring perovskite layers. Magnetic studies show the absence of long-range magnetic ordering down to 2 K despite strong in-plane interactions. Aleksandrov Prime s group theory and Rietveld refinement of synchrotron X-ray diffraction data suggest the structure to be of I4/mmm space group with in-phase tilting along the a and b axes, a two-tilt system (++0). - Graphical Abstract: We present a quadruple-layered copper oxyhalide (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13} synthesized through a topotactic ion-exchange reaction of RbCa{sub 2}NaNb{sub 4}O{sub 13} with CuCl{sub 2}. The compound has a well-defined superstructure. Magnetic studies suggest the absence of magnetic order even at 2 K. Highlights: Black-Right-Pointing-Pointer (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13} was prepared by ion-exchange reaction of RbCa{sub 2}NaNb{sub 4}O{sub 13} with CuCl{sub 2}. Black-Right-Pointing-Pointer Compound has a 2a{sub p} Multiplication-Sign 2a{sub p} Multiplication-Sign 2c{sub p} superstructure (tetragonal; a=7.73 A, c=39.21 A). Black-Right-Pointing-Pointer Such a well-defined superstructure was not observed in the precursor compound. Black-Right-Pointing-Pointer Aleksandrov Prime s theory and Rietveld study suggest a (++0) octahedral tilting (I4/mmm). Black-Right-Pointing-Pointer Magnetic studies revealed the absence of magnetic order down to 2 K.

  19. Structure, magnetism, specific heat, and dielectric properties of Eu{sub 2}Ta{sub 2}O{sub 7}

    SciTech Connect (OSTI)

    Kolodiazhnyi, T. Sakurai, H.; Matsushita, Y.

    2014-11-17

    Polycrystalline Eu{sub 2}Ta{sub 2}O{sub 7} containing layered perovskite slabs was prepared and analyzed. Eu{sub 2}Ta{sub 2}O{sub 7} crystallizes in the orthorhombic centrosymmetric Cmcm space group (with unit cell: a?=?3.95156(9), b?=?27.0775(6), and c?=?5.68279(13) ) isomorphous with high-temperature Sr{sub 2}Ta{sub 2}O{sub 7}. Dielectric measurements reveal that, in contrast to Sr{sub 2}Ta{sub 2}O{sub 7} which is ferroelectric below 166?K, Eu{sub 2}Ta{sub 2}O{sub 7} remains paraelectric down to at least 0.45?K and shows no magneto-dielectric coupling. Magnetic data in the 2400?K range indicate an antiferromagnetic phase transition with a sharp susceptibility peak at 2.71(5) K. Further analysis using specific heat measurements reveals that the second magnetic phase transition occurs at 1.10(5) K and dominates the spin entropy of the Eu{sup 2+} 4f{sup 7} ions. The possible origin of the two successive magnetic phase transitions in Eu{sub 2}Ta{sub 2}O{sub 7} requires further studies.

  20. CO.sub.2 laser

    DOE Patents [OSTI]

    Rink, John P.

    1977-01-01

    The disclosure relates to a pulsed gas laser comprising an optical resonant cavity, a CO.sub.2 lasing medium, structure for containing the CO.sub.2 lasing medium within the optical cavity and a device for causing a population inversion in the lasing medium, with a novel improvement comprising structure for causing a laser pulse comprising a wavelength in the near 14 .mu.m and near 16 .mu.m range. The structure for cooling the CO.sub.2 lasing medium to less than about -40.degree. C as well is a structure for pumping the maximum inversion of CO.sub.2 molecules within the lasing medium by minimizing the population in the 010 level.

  1. Advanced Sub-Metering Program

    Broader source: Energy.gov [DOE]

    The program is designed to provide information about energy usage for each residences at a multi-residential buildings. Residences living in multi-residential buildings that are not sub-metered d...

  2. Highly efficient photocatalysis of p-type Cu{sub 2}ZnSnS{sub 4} under visible-light illumination

    SciTech Connect (OSTI)

    Hou, Xian; Li, Yan Yan, Jian-Jun; Wang, Cheng-Wei

    2014-12-15

    Highlights: Kesterite CZTS nanocrystal powder was synthesized by one-pot method. First successful use CZTS nanocrystal powder as photocatalyst. CZTS shows an efficient photocatalysis under visible light irradiation. CZTS photocatalyst having excellent stability. - Abstract: Cu{sub 2}ZnSnS{sub 4}, as a very promising p-type semiconductor material, has been extensively used in the study of solar cells owing to its suitable band gap (1.11.5 eV), large absorption coefficient of 10{sup 4} cm{sup ?1} in the visible spectrum, good photo stability, nontoxicity and relative abundance of the component elements. In this paper, we have successfully synthesized p-type kesterite Cu{sub 2}ZnSnS{sub 4} nanocrystal powder by facile one-pot method, and made our first successful attempt to use Cu{sub 2}ZnSnS{sub 4} nanocrystal powder as a photocatalyst to degradation methyl orange under visible-light irradiation. The exciting results show that in the visible light region, Cu{sub 2}ZnSnS{sub 4} nanocrystal powder possesses an excellent photocatalytic performance of K = 0.0317 min{sup ?1}, nearly about 6 times of well known commercial P25 titania powder performance under the same conditions, which suggests that the p-type kesterite Cu{sub 2}ZnSnS{sub 4} nanocrystal would be a promising candidate of photocatalyst.

  3. Effect of hydrogen ratio on plasma parameters of N{sub 2}-H{sub 2} gas mixture glow discharge

    SciTech Connect (OSTI)

    El-Brulsy, R. A.; Abd Al-Halim, M. A.; Abu-Hashem, A.; Rashed, U. M.; Hassouba, M. A.

    2012-05-15

    A dc plane glow discharge in a nitrogen-hydrogen (N{sub 2}-H{sub 2}) gas mixture has been operated at discharge currents of 10 and 20 mA. The electron energy distribution function (EEDF) at different hydrogen concentrations is measured. A Maxwellian EEDF is found in the positive column region, while in both cathode fall and negative glow regions, a non-Maxwellian one is observed. Langmuir electric probes are used at different axial positions, gas pressures, and hydrogen concentrations to measure the electron temperature and plasma density. The electron temperature is found to increase with increasing H{sub 2} concentration and decrease with increasing both the axial distance from the cathode and the mixture pressure. At first, with increasing distance from the cathode, the ion density decreases, while the electron density increases; then, as the anode is further approached, they remain nearly constant. At different H{sub 2} concentrations, the electron and ion densities decrease with increasing the mixture pressure. Both the electron and ion densities slightly decrease with increasing H{sub 2} concentration.

  4. Fluorination behavior of UO{sub 2}F{sub 2} in the presence of F{sub 2} and O{sub 2}

    SciTech Connect (OSTI)

    Matsuda, Minoru; Sato, Nobuaki; Kirishima, Akira; Tochiyama, Osamu

    2007-07-01

    To apply the fluoride volatility process to the spent nuclear fuel, fluorination of UO{sub 2} by fluorine has been studied. In this reaction, it is possible that the U-O-F compounds, such as UO{sub 2}F{sub 2}, are produced. Therefore, study of such compounds is useful in order to know the fluorination behavior of UO{sub 2}. This paper presents the fluorination behavior of UO{sub 2}F{sub 2} in the presence of F{sub 2} and O{sub 2}, analyzed by thermogravimetry and differential thermal analysis (TG-DTA) method using anti-corrosion type differential thermo-balance. In fluorine gas, exothermic peaks appeared and volatilization of UF{sub 6}. In oxygen gas, only slowly pace decomposition was measured from UO{sub 22} to UF{sub 6} and UO{sub 3}. (authors)

  5. Development of interatomic potentials appropriate for simulation of devitrification of Al<sub>90sub>Sm>10sub> alloy

    SciTech Connect (OSTI)

    Mendelev, M. I.; Zhang, F.; Ye, Z.; Sun, Y.; Nguyen, M. C.; Wilson, S. R.; Wang, C. Z.; Ho, K. M.

    2015-04-23

    In this study, a semi-empirical potential for the Al<sub>90sub>Sm>10sub> alloy is presented. The potential provides satisfactory reproduction of pure Al properties, the formation energies of a set of Al–Sm crystal phases with Sm content about 10%, and the structure of the liquid Al<sub>90sub>Sm>10sub> alloy. During molecular dynamics simulation in which the liquid alloy is cooled at a rate of 1010 K/s, the developed potential produces a glass structure with lower ab initio energy than that produced by ab initio molecular dynamics (AIMD) itself using a typical AIMD cooling rate of 8 ∙1013 K/s. Based on these facts the developed potential should be suitable for simulations of phase transformations in the Al<sub>90sub>Sm>10sub> alloy.

  6. Disorder from order among anisotropic next-nearest-neighbor Ising spin chains in SrHo<sub>2sub>O>4sub>

    SciTech Connect (OSTI)

    Wen, J. -J.; Tian, W.; Garlea, V. O.; Koohpayeh, S. M.; McQueen, T. M.; Li, H. -F.; Yan, J. -Q.; Rodriguez-Rivera, J. A.; Vaknin, D.; Broholm, C. L.

    2015-02-26

    In this study, we describe why Ising spin chains with competing interactions in SrHo<sub>2sub>O>4sub> segregate into ordered and disordered ensembles at low temperatures (T). Using elastic neutron scattering, magnetization, and specific heat measurements, the two distinct spin chains are inferred to have Nel (????) and double-Nel (????) ground states, respectively. Below T<sub>N> = 0.68(2)K, the Nel chains develop three-dimensional long range order (LRO), which arrests further thermal equilibration of the double-Nel chains so they remain in a disordered incommensurate state for T below T<sub>S> = 0.52(2)K. SrHo<sub>2sub>O>4sub> distills an important feature of incommensurate low dimensional magnetism: kinetically trapped topological defects in a quasiddimensional spin system can preclude order in d + 1 dimensions.

  7. Enhanced ferromagnetic order in Sr{sub 4}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} featuring canted [MnO{sub 4}]{sub ∞} spin chains of mixed-valent Mn(III)/Mn(IV). Aliovalent substitution of the Sr{sub 4−x}Ln{sub x}Mn{sup III}{sub 2+x}Mn{sup IV}{sub 1−x}O{sub 3}(GeO{sub 4}){sub 3} solid-solution

    SciTech Connect (OSTI)

    West, J. Palmer; Sulejmanovic, Dino; Becht, Gregory; He, Jian; Hitchcock, Dale; Yan, Yonggao; Hwu, Shiou-Jyh

    2013-10-15

    Crystals of Sr{sub 4−x}Ln{sub x}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} (x=0; x∼0.15 for Ln=La, Pr, Nd, Sm. Eu, Gd, Dy; x∼0.3 for Ln=Gd) were isolated upon using high-temperature, solid-state methods in molten-salt media. These compounds are isostructural with the previously reported Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3} (Ln=La, Sm, Gd) series that contains the same [MnO{sub 4}]{sub ∞} spin chains. The synthesis of the Sr{sub 4}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} (x=0) phase was carried out by a double aliovalent substitution with respect to the Sr{sup 2+} and Ge{sup 4+} ions that replace Na{sup +}/Ln{sup 3+} and As{sup 5+} in Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3}, respectively. The title series contains mixed-valent Mn(III)/Mn(IV) and shows a limited range of solid solution, both of which were not observed in the previously reported Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3} series. To form the Sr{sub 4−x}Ln{sub x}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} solid solution, one of the Sr{sup 2+} sites, i.e., the original Ln-site in Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3}, is partially substituted by Ln{sup 3+} in a statistical disorder of Sr{sub 1−x}/Ln{sub x}. Initial magnetic investigations of selected derivatives reveal higher ferromagnetic ordering temperatures than those reported for the Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3} series, presumably attributed to a lesser degree of canting as a result of introducing non-Jahn–Teller Mn{sup 4+} ions. Also intriguing is the observation of multiple anomalies at low temperatures which appear to be of electronic origins. - Graphical abstract: Sr{sub 4−x}Ln{sub x}Mn(III){sub 2+x}Mn(IV){sub 1−x}O{sub 3}(GeO{sub 4}){sub 3}. Display Omitted - Highlights: • Double aliovalent substitution: Sr{sub 4}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} with respect to Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3}. • Solid solution with respect to statistical disorder of Sr{sub 1−x}Ln{sub x} in one of the two Sr sites. • Mn{sup 3+}/Mn{sup 4+} magnetic ions are spatially arranged in a triangular kagomé fashion. • Enhanced ferromagnetic ordering attributed to doping non-Jahn–Teller Mn{sup 4+}.

  8. Ti{sub 5}O{sub 5} superstructures of cubic titanium monoxide

    SciTech Connect (OSTI)

    Gusev, A. I.

    2013-08-15

    A cubic model is proposed for the Ti{sub 5}O{sub 5} (Ti{sub 5} Black-Small-Square O{sub 5}{open_square} {identical_to} Ti{sub 90} Black-Small-Square {sub 18}O{sub 90}{open_square}{sub 18}) superstructure of nonstoichiometric titanium monoxide Ti{sub x}O{sub z} with double imperfection. The unit cell of the cubic Ti{sub 5}O{sub 5} superstructure has the threefold lattice parameter of the unit cell of the basis disordered B1 structure of Ti{sub x}O{sub z} monoxide and belongs to space group Pm 3-bar m . The channel of the disorder-order transition, i.e., Ti{sub x}O{sub z} (space group Fm 3-bar m)-Ti{sub 5}O{sub 5} (space group Pm 3-bar m), includes 75 superstructure vectors of seven stars (k{sub 10}), (k{sub 7}), (k{sub 6(1)}), (k{sub 6(2)}), (k{sub 4(1)}), (k{sub 4(2)}), and (k{sub 1}). The distribution functions of Ti and O atoms over the sites of the cubic Ti{sub 5}O{sub 5} superstructure are calculated. A comparison of the X-ray and electron diffraction data obtained for ordered TiO{sub 1.087} monoxide with the theoretical simulation results supports the existence of the cubic Ti{sub 5}O{sub 5} superstructure. The cubic (space group Pm 3-bar m) Ti{sub 5}O{sub 5} superstructure is shown to be a high-temperature structure relative to the well-known monoclinic (space group C2/m) superstructure of the same type.

  9. Eu{sup 2+}, Mn{sup 2+} co-doped Ba{sub 9}Y{sub 2}Si{sub 6}O{sub 24} phosphors based on near-UV-excitable LED lights

    SciTech Connect (OSTI)

    Kim, Yoejin; Park, Sangmoon

    2014-01-01

    Graphical abstract: - Highlights: • New near-ultraviolet (NUV)-excitable materials composed of Ba{sub 9}Eu{sub m}Mn{sub n}Y{sub 2}Si{sub 6}O{sub 24} (m = 0.01–0.5, n = 0–0.7) were prepared. • High energy-transfer from Eu{sup 2+} to Mn{sup 2+} and their energy-transfer mechanism were discussed. • The co-doping of Eu{sup 2+} and Mn{sup 2+} in the orthosilicate structure resulted in the emission of white light under NUV LED light. - Abstract: New single-phase and near-ultraviolet (NUV)-excitable materials composed of Ba{sub 9}Eu{sub m}Mn{sub n}Y{sub 2}Si{sub 6}O{sub 24} (m = 0.01–0.5, n = 0–0.7) were prepared via a solid-state reaction in reducing atmosphere. X-ray diffraction patterns of the obtained phosphors were examined to index the peak positions. After doping the host structure with Eu{sup 2+} and Mn{sup 2+} emitters, the intense green, white, and orange emission lights that were observed in the photoluminescence spectra under NUV excitation were monitored. The dependence of the luminescent intensity of the Mn{sup 2+} co-doped (n = 0.1–0.7) host lattices on the fixed Eu{sup 2+} content (m = 0.1, 0.3, 0.5) is also investigated. Co-doping Mn{sup 2+} into the Eu{sup 2+}-doped host structure enabled a high energy-transfer from Eu{sup 2+} to Mn{sup 2+} and their energy-transfer mechanism were discussed. Using these phosphors, the desired CIE values including emissions throughout the green to orange regions of the spectra were achieved. Efficient white-light light-emitting diodes (LEDs) were fabricated using Eu{sup 2+} and Mn{sup 2+} co-doped phosphors based on NUV-excitable LED lights.

  10. Synthetic CO.sub.2 acceptor

    DOE Patents [OSTI]

    Lancet, Michael S.; Curran, George P.

    1981-08-18

    A synthetic CO.sub.2 acceptor consisting essentially of at least one compound selected from the group consisting of calcium oxide and calcium carbonate supported in a refractory carrier matrix, the carrier having the general formula Ca.sub.5 (SiO.sub.4).sub.2 CO.sub.3. A method for producing the synthetic CO.sub.2 acceptor is also disclosed.

  11. The new Hg-rich barium indium mercurides BaIn{sub x}Hg{sub 7−x} (x=3.1) and BaIn{sub x}Hg{sub 11−x} (x=0–2.8)

    SciTech Connect (OSTI)

    Wendorff, Marco; Schwarz, Michael; Röhr, Caroline

    2013-07-15

    The title compounds BaIn{sub x}Hg{sub 7−x} (x=3.1(1)) and BaIn{sub x}Hg{sub 11−x} (x=0–2.8) were synthesized from stoichiometric ratios of the elements in Ta crucibles. Their crystal structures have been determined using single crystal X-ray data. BaIn{sub x}Hg{sub 7−x} (x=3.1(1)) crystallizes in a new structure type (orthorhombic, oC16, space group Cmmm: a=512.02(1), b=1227.68(3), c=668.61(2) pm, Z=2, R1=0.0311). In the structure, the atoms of the three crystallographically different mixed In/Hg positions form planar nets of four-, six- and eight-membered rings. These nets are shifted against each other such that the four-membered rings form empty distorted cubes. The cubes are connected via common edges, corners and folded ladders, which are also found in BaIn{sub 2}/BaHg{sub 2} (KHg{sub 2} structure type) and BaIn (α-NaHg type). The Ba atoms are centered in the eight-membered rings and exhibit an overall coordination number of 20. The [BaM{sub 20}] polyhedra and twice as many distorted [M{sub 8}] cubes tesselate the space. BaIn{sub 2.8}Hg{sub 8.2} (cubic, cP36, space group Pm3{sup ¯}m, a=961.83(1) pm, Z=3, R1=0.0243) is the border compound of the phase width BaIn{sub x}Hg{sub 11−x} of the rare BaHg{sub 11} structure type. In the structure, ideal [M{sub 8}] cubes (at the corners of the unit cell) and BaM{sub 20} polyhedra (at the edges of the unit cell) represent the building blocks comparable to the other new In mercuride. In accordance with the increased In/Hg content, additional M-pure regions appear: the center of the unit cell contains a huge [Hg(1)M(2){sub 12}M(3,4){sub 32}] polyhedron, a Hg-centered cuboctahedron of In/Hg atoms surrounded by a capped cantellated cube of 32 additional M atoms. For both structure types, the bonding situation and the ‘coloring’, i.e. the In/Hg distribution of the polyanionic network, are discussed considering the different sizes of the atoms and the charge distribution (Bader AIM charges), which have been calculated within the framework of FP-LAPW density functional theory. - Graphical abstract: BaIn{sub 2.6}Hg{sub 4.4}: distorted cubes [(In/Hg){sub 8}] (green, like in BaHg{sub 11}), folded ladders (violet, like in BaIn, BaHg{sub 2} and BaIn{sub 2}) and Ba coordination polyhedra [Ba(In/Hg){sub 20}] (blue, like in BaHg{sub 11}). - Highlights: • The Hg-rich In-mercuride BaIn{sub 3.1}Hg{sub 3.9} crystallizes with a singular structure type. • The phase width of the BaHg{sub 11} structure in BaIn{sub x}Hg{sub 11-x} ends at x=2.8. • The relations of both compounds with other alkaline-earth mercurides are outlined. • The Hg/In coloring of the polyanion is discussed considering the structure features. • Bonding aspects are explored using band structure calculations.

  12. High thermal stability Sb{sub 3}Te-TiN{sub 2} material for phase change memory application

    SciTech Connect (OSTI)

    Ji, Xinglong; Zhou, Wangyang; Wu, Liangcai Zhu, Min; Rao, Feng; Song, Zhitang; Cao, Liangliang; Feng, Songlin

    2015-01-12

    For phase change memory (PCM) applications, it has been widely accepted that δ phase Sb-Te has fast operation speed and good phase stability. However, the fast growth crystallization mechanism will cause poor amorphous phase stability and overlarge grain size. We introduce TiN{sub 2} into δ phase Sb-Te (Sb{sub 3}Te) to enhance the amorphous thermal stability and refine the grain size. With TiN{sub 2} incorporating, the temperature for 10-year data retention increases from 79 °C to 124 °C. And the grain size decreases to dozens of nanometers scale. Based on X-ray photoelectron spectroscopy and transmission electron microscopy results, we knew that nitrogen atoms bond with titanium, forming disorder region at the grain boundary of Sb{sub 3}Te-TiN{sub 2} (STTN). Thus, STTN has a quite different crystallization mechanism from Sb{sub 3}Te. Furthermore, PCM device based on STTN can realize reversible phase change under 20 ns electrical pulse.

  13. Neutron powder diffraction analysis of (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3}

    Office of Scientific and Technical Information (OSTI)

    and (Lu{sub 0.50}Ca{sub 0.50})MnO{sub 3} (Journal Article) | SciTech Connect Neutron powder diffraction analysis of (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} and (Lu{sub 0.50}Ca{sub 0.50})MnO{sub 3} Citation Details In-Document Search Title: Neutron powder diffraction analysis of (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} and (Lu{sub 0.50}Ca{sub 0.50})MnO{sub 3} The crystal and magnetic structures of (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} and (Lu{sub 0.50}Ca{sub 0.50})MnO{sub 3} have been investigated

  14. Pumping-route-dependent concentration quenching and temperature effect of green up- and down-conversion luminescence in Er{sup 3+}/Yb{sup 3+} co-doped Gd{sub 2}(WO{sub 4}){sub 3} phosphors

    SciTech Connect (OSTI)

    Li, Jingjing; Sun, Jiashi [Department of Physics, Dalian Maritime University, Dalian, Liaoning 116026 (China); Liu, Jutao [College of Life Science, Dalian Nationalities University, Dalian, Liaoning 116600 (China); Li, Xiangping; Zhang, Jinsu [Department of Physics, Dalian Maritime University, Dalian, Liaoning 116026 (China); Tian, Yue [Department of Physics, Dalian Maritime University, Dalian, Liaoning 116026 (China); College of Life Science, Dalian Nationalities University, Dalian, Liaoning 116600 (China); Fu, Shaobo; Cheng, Lihong; Zhong, Haiyang [Department of Physics, Dalian Maritime University, Dalian, Liaoning 116026 (China); Xia, Haiping [Key laboratory of Photo-electronic Materials, Ningbo University, Ningbo, Zhejiang 315211 (China); Chen, Baojiu, E-mail: chenmbj@sohu.com [Department of Physics, Dalian Maritime University, Dalian, Liaoning 116026 (China)

    2013-06-01

    Graphical abstract: A comparative study on the concentration quenching behaviors of green down- and up-conversion emissions was carried out for the first time, and the different concentration quenching mechanisms were analyzed. Secondly, the thermal effect induced by 980 nm LD irradiation was investigated, it was observed that the equilibrium temperature of Gd{sub 2}(WO{sub 4}){sub 3}:Er{sup 3+}/Yb{sup 3+} sample was decided by both the excitation power and Er{sup 3+} doping concentration. Highlights: ? Gd{sub 2}(WO{sub 4}){sub 3}:Er/Yb phosphors were prepared via a co-precipitation reaction. ? Morphology and structure of the phosphors were characterized by XRD and SEM. ? Concentration quenching mechanisms for down and up emissions were studied. ? Thermal effect induced by laser irradiation was studied via temperature sensing tech. - Abstract: Gd{sub 2}(WO{sub 4}){sub 3} phosphors with various Er{sup 3+} concentrations and fixed Yb{sup 3+} concentration were synthesized via a co-precipitation method, and their crystal structure and morphology were characterized by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The concentration quenching behaviors of green up- and down-conversion emissions of Er{sup 3+} were analyzed, and it was confirmed that the difference between quenching concentration for up- and down-conversion emissions resulted from the different population routes. The temperature sensing properties of the Gd{sub 2}(WO{sub 4}){sub 3}:Er{sup 3+}/Yb{sup 3+} phosphors were studied, and it was found that the Er{sup 3+} doping concentration slightly affected the sensitivity, and Gd{sub 2}(WO{sub 4}){sub 3}:Er{sup 3+}/Yb{sup 3+} phosphors could be used in a broad temperature region for detecting temperature. Finally, the thermal effect induced by 980 nm LD irradiation was investigated, it was observed that the equilibrium temperature of Gd{sub 2}(WO{sub 4}){sub 3}:Er{sup 3+}/Yb{sup 3+} sample was decided by both the excitation power and Er{sup 3+} doping concentration.

  15. Energy efficient microwave synthesis of mesoporous Ce<sub>0.5sub>M>0.5sub>O>2sub> (Ti, Zr, Hf) nanoparticles for low temperature CO oxidation in an ionic liquid – a comparative study

    SciTech Connect (OSTI)

    Alammar, Tarek; Chow, Ying -Kit; Mudring, Anja -Verena

    2014-11-19

    Ce<sub>0.5sub>M>0.5sub>O>2sub> (M = Ti, Zr, Hf) nanoparticles have been successfully synthesized by microwave irradiation in the ionic liquid [C<sub>4sub>mim][Tf>2sub>N] (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide). The morphology, crystallinity, and chemical composition of the obtained materials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and N<sub>2sub>–adsorption measurements. XRD and Raman spectroscopy analyses confirmed the formation of solid solutions with cubic fluorite structure. The catalytic activities of the Ce<sub>0.5sub>M>0.5sub>O>2sub> (M = Ti, Zr, Hf) nanoparticles were investigated in the low-temperature oxidation of CO. Ce<sub>0.5sub>Zr>0.5sub>O>2sub> nanospheres exhibit the best performance (100% conversion at 350 °C), followed by Ce<sub>0.5sub>Hf>0.5sub>O>2sub> (55% conversion at 360 °C) and Ce<sub>0.5sub>Ti>0.5sub>O>2sub> (11% conversion at 350 °C). Heating the as-prepared Ce<sub>0.5sub>Zr>0.5sub>O>2sub> to 600 °C for extended time leads to a decrease in surface area and, as expected decreased catalytic activity. Depending on the ionic liquid the obtained Ce<sub>0.5sub>Zr>0.5sub>O>2sub> exhibits different morphologies, varying from nano-spheres in [C<sub>4sub>mim][Tf>2sub>N] and [P<sub>66614sub>][Tf>2sub>N] (P<sub>66614sub> = trishexyltetradecylphosphonium) to sheet-like assemblies in [C<sub>3sub>mimOH][Tf>2sub>N] (C<sub>3sub>mimOH = 1-(3-hydroxypropyl)-3-methylimidazolium). As a result, the microwave synthesis superiority to other heating methods like sonochemical synthesis and conventional heating was proven by comparative experiments where the catalytic activity of Ce<sub>0.5sub>Zr>0.5sub>O>2sub> obtained by alternate methods such as conventional heating was found to be poorer than that of the microwave-synthesised material.

  16. Magnetic field induced anisotropy of 139La spin-lattice relaxation rates in stripe ordered La<sub>1.875sub>Ba>0.125sub>CuO>4sub>

    SciTech Connect (OSTI)

    S. -H. Baek; Gu, G. D.; Utz, Y.; Hucker, M.; Buchner, B.; Grafe, H. -J.

    2015-10-26

    We report 139La nuclear magnetic resonance studies performed on a La<sub>1.875sub>Ba>0.125sub>CuO>4sub> single crystal. The data show that the structural phase transitions (high-temperature tetragonal → low-temperature orthorhombic → low-temperature tetragonal phase) are of the displacive type in this material. The 139La spin-lattice relaxation rate T–1<sub>1sub> sharply upturns at the charge-ordering temperature T<sub>CO> = 54 K, indicating that charge order triggers the slowing down of spin fluctuations. Detailed temperature and field dependencies of the T–1<sub>1sub> below the spin-ordering temperature T<sub>SO>=40 K reveal the development of enhanced spin fluctuations in the spin-ordered state for H ∥ [001], which are completely suppressed for large fields along the CuO<sub>2sub> planes. Lastly, our results shed light on the unusual spin fluctuations in the charge and spin stripe ordered lanthanum cuprates.

  17. Cobalt-doped Bi{sub 26}Mo{sub 10}O{sub 69}: Crystal structure and conductivity

    SciTech Connect (OSTI)

    Mikhailovskaya, Z.A.; Buyanova, E.S.; Petrova, S.A.; Morozova, M.V.; Zhukovskiy, V.M.; Zakharov, R.G.; Tarakina, N.V.; Berger, I.F.

    2013-08-15

    A series of cobalt-doped bismuth molybdates were synthesized and investigated using X-ray powder diffraction, transmission electron microscopy and impedance spectroscopy. The ranges of solid solution were determined. Two new compounds, Bi{sub 1?x}Co{sub x}[Bi{sub 12}O{sub 14}]Mo{sub 5}O{sub 34.5?} (x=0.2) and Bi[Bi{sub 12}O{sub 14}]Mo{sub 5?y}Co{sub y}O{sub 34.5?} (y=0.2), which crystallise in monoclinic unit cells have been examined in detail by diffraction methods. Impedance spectroscopy measurements show that the studied materials are good ionic conductors with conductivity values about 510{sup ?3} Scm{sup ?1} at 973 K and 1.710{sup ?4} Scm{sup ?1} at 623 K, which are similar to conductivity values of yttrium substituted zirconia and (YSZ) gadolinium doped ceria (CGO). - Graphical abstract: Measured and calculated diffraction spectra for Bi{sub 12.8}Co{sub 0.2}Mo{sub 5}O{sub 34?} and projection of the Bi{sub 12.8}Co{sub 0.2}Mo{sub 5}O{sub 34?} crystal structure onto the ac plane. Highlights: The limit of the Bi{sub 1?x}Co{sub x}[Bi{sub 12}O{sub 14}]Mo{sub 5}O{sub 34.5?} homogeneity range is equal to x=0.2. The limit of the Bi[Bi{sub 12}O{sub 14}]Mo{sub 5?y}Co{sub y}O{sub 34.5?} homogeneity range is equal to y=0.2. Solid solutions have monoclinic symmetry. No phase transition is observed. The conductivity at 700 for y=0.2 solid solutions is equal to ?lg ?, Scm{sup ?1}=2.23. The conductivity at 350 for y=0.2 solid solutions is equal to ?lg ?, Scm{sup ?1}=3.74.

  18. Search for dark photons from neutral meson decays in p+p and d+Au collisions at √s<sub>NN> = 200 GeV

    SciTech Connect (OSTI)

    Adare, A.; Afanasiev, S.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Akimoto, R.; Al-Bataineh, H.; Al-Ta'ani, H.; Alexander, J.; Alfred, M.; Andrews, K. R.; Angerami, A.; Aoki, K.; Apadula, N.; Aphecetche, L.; Appelt, E.; Aramaki, Y.; Armendariz, R.; Asai, J.; Asano, H.; Aschenauer, E. C.; Atomssa, E. T.; Averbeck, R.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Baksay, G.; Baksay, L.; Baldisseri, A.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Barnes, P. D.; Bassalleck, B.; Basye, A. T.; Bathe, S.; Batsouli, S.; Baublis, V.; Baumann, C.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belikov, S.; Belmont, R.; Ben-Benjamin, J.; Bennett, R.; Berdnikov, A.; Berdnikov, Y.; Bhom, J. H.; Bickley, A. A.; Black, D.; Blau, D. S.; Boissevain, J. G.; Bok, J. S.; Borel, H.; Boyle, K.; Brooks, M. L.; Broxmeyer, D.; Bryslawskyj, J.; Buesching, H.; Bumazhnov, V.; Bunce, G.; Butsyk, S.; Camacho, C. M.; Campbell, S.; Caringi, A.; Castera, P.; Chang, B. S.; Chang, W. C.; Charvet, J. L.; Chen, C. H.; Chernichenko, S.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choudhury, R. K.; Christiansen, P.; Chujo, T.; Chung, P.; Churyn, A.; Chvala, O.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Conesa del Valle, Z.; Connors, M.; Constantin, P.; Csanád, M.; Csörgő, T.; Dahms, T.; Dairaku, S.; Danchev, I.; Das, K.; Datta, A.; Daugherity, M. S.; David, G.; Dayananda, M. K.; DeBlasio, K.; Dehmelt, K.; Denisov, A.; d'Enterria, D.; Deshpande, A.; Desmond, E. J.; Dharmawardane, K. V.; Dietzsch, O.; Ding, L.; Dion, A.; Do, J. H.; Donadelli, M.; Drapier, O.; Drees, A.; Drees, K. A.; Dubey, A. K.; Durham, J. M.; Durum, A.; Dutta, D.; Dzhordzhadze, V.; D'Orazio, L.; Edwards, S.; Efremenko, Y. V.; Ellinghaus, F.; Engelmore, T.; Enokizono, A.; En'yo, H.; Esumi, S.; Eyser, K. O.; Fadem, B.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Fraenkel, Z.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fujiwara, K.; Fukao, Y.; Fusayasu, T.; Gal, C.; Gallus, P.; Garg, P.; Garishvili, I.; Ge, H.; Giordano, F.; Glenn, A.; Gong, H.; Gong, X.; Gonin, M.; Gosset, J.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grim, G.; Grosse Perdekamp, M.; Gu, Y.; Gunji, T.; Guo, L.; Guragain, H.; Gustafsson, H. Å.; Hachiya, T.; Hadj Henni, A.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamblen, J.; Han, R.; Han, S. Y.; Hanks, J.; Harper, C.; Hartouni, E. P.; Haruna, K.; Hasegawa, S.; Hashimoto, K.; Haslum, E.; Hayano, R.; He, X.; Heffner, M.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hohlmann, M.; Hollis, R. S.; Holzmann, W.; Homma, K.; Hong, B.; Horaguchi, T.; Hori, Y.; Hornback, D.; Hoshino, T.; Huang, J.; Huang, S.; Ichihara, T.; Ichimiya, R.; Iinuma, H.; Ikeda, Y.; Imai, K.; Imazu, Y.; Imrek, J.; Inaba, M.; Iordanova, A.; Isenhower, D.; Ishihara, M.; Isobe, T.; Issah, M.; Isupov, A.; Ivanischev, D.; Ivanishchev, D.; Iwanaga, Y.; Jacak, B. V.; Jeon, S. J.; Jezghani, M.; Jia, J.; Jiang, X.; Jin, J.; John, D.; Johnson, B. M.; Jones, T.; Joo, E.; Joo, K. S.; Jouan, D.; Jumper, D. S.; Kajihara, F.; Kametani, S.; Kamihara, N.; Kamin, J.; Kaneti, S.; Kang, B. H.; Kang, J. H.; Kang, J. S.; Kapustinsky, J.; Karatsu, K.; Kasai, M.; Kawall, D.; Kawashima, M.; Kazantsev, A. V.; Kempel, T.; Key, J. A.; Khachatryan, V.; Khanzadeev, A.; Kihara, K.; Kijima, K. M.; Kikuchi, J.; Kim, A.; Kim, B. I.; Kim, C.; Kim, D. H.; Kim, D. J.; Kim, E.; Kim, E. J.; Kim, H. J.; Kim, M.; Kim, S. H.; Kim, Y. J.; Kim, Y. K.; Kinney, E.; Kiriluk, K.; Kiss, Á.; Kistenev, E.; Klatsky, J.; Klay, J.; Klein-Boesing, C.; Kleinjan, D.; Kline, P.; Koblesky, T.; Kochenda, L.; Kofarago, M.; Komkov, B.; Konno, M.; Koster, J.; Kotov, D.; Kozlov, A.; Král, A.; Kravitz, A.; Kunde, G. J.; Kurita, K.; Kurosawa, M.; Kweon, M. J.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Layton, D.; Lebedev, A.; Lee, D. M.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, S. H.; Lee, S. R.; Lee, T.; Leitch, M. J.; Leite, M. A. L.; Leitgab, M.; Lenzi, B.; Li, X.; Lichtenwalner, P.; Liebing, P.; Lim, S. H.; Linden Levy, L. A.; Liška, T.; Litvinenko, A.; Liu, H.; Liu, M. X.; Love, B.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Makek, M.; Malakhov, A.; Malik, M. D.; Manion, A.; Manko, V. I.; Mannel, E.; Mao, Y.; Mašek, L.; Masui, H.; Matathias, F.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Means, N.; Meles, A.; Mendoza, M.; Meredith, B.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Mikeš, P.; Miki, K.; Miller, A. J.; Milov, A.; Mishra, D. K.; Mishra, M.; Mitchell, J. T.; Miyachi, Y.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Montuenga, P.; Moon, H. J.; Moon, T.; Morino, Y.; Morreale, A.; Morrison, D. P.; Motschwiller, S.; Moukhanova, T. V.; Mukhopadhyay, D.; Murakami, T.; Murata, J.; Mwai, A.; Nagamiya, S.; Nagle, J. L.; Naglis, M.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nam, S.; Nattrass, C.; Netrakanti, P. K.; Newby, J.; Nguyen, M.; Nihashi, M.; Niida, T.; Nouicer, R.; Novitzky, N.; Nyanin, A. S.; Oakley, C.; O'Brien, E.; Oda, S. X.; Ogilvie, C. A.; Oka, M.; Okada, K.; Onuki, Y.; Orjuela Koop, J. D.; Oskarsson, A.; Ouchida, M.; Ozaki, H.; Ozawa, K.; Pak, R.; Palounek, A. P. T.; Pantuev, V.; Papavassiliou, V.; Park, B. H.; Park, I. H.; Park, J.; Park, S.; Park, S. K.; Park, W. J.; Pate, S. F.; Patel, L.; Patel, M.; Pei, H.; Peng, J. C.; Pereira, H.; Perepelitsa, D. V.; Perera, G. D. N.; Peresedov, V.; Peressounko, D. Yu.; Perry, J.; Petti, R.; Pinkenburg, C.; Pinson, R.; Pisani, R. P.; Proissl, M.; Purschke, M. L.; Purwar, A. K.; Qu, H.; Rak, J.; Rakotozafindrabe, A.; Ravinovich, I.; Read, K. F.; Rembeczki, S.; Reygers, K.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richardson, E.; Riveli, N.; Roach, D.; Roche, G.; Rolnick, S. D.; Rosati, M.; Rosen, C. A.; Rosendahl, S. S. E.; Rosnet, P.; Rowan, Z.; Rubin, J. G.; Rukoyatkin, P.; Ružička, P.; Rykov, V. L.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sakai, S.; Sakashita, K.; Sako, H.; Samsonov, V.; Sano, S.; Sarsour, M.; Sato, S.; Sato, T.; Savastio, M.; Sawada, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seele, J.; Seidl, R.; Semenov, A. Yu.; Semenov, V.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shein, I.; Shibata, T. A.; Shigaki, K.; Shim, H. H.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Silvestre, C.; Sim, K. S.; Singh, B. K.; Singh, C. P.; Singh, V.; Slunečka, M.; Sodre, T.; Soldatov, A.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Staley, F.; Stankus, P. W.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Sugitate, T.; Suire, C.; Sukhanov, A.; Sumita, T.; Sun, J.; Sziklai, J.; Takagui, E. M.; Takahara, A.; Taketani, A.; Tanabe, R.; Tanaka, Y.; Taneja, S.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tarján, P.; Tennant, E.; Themann, H.; Thomas, D.; Thomas, T. L.; Timilsina, A.; Todoroki, T.; Togawa, M.; Toia, A.; Tomášek, L.; Tomášek, M.; Tomita, Y.; Torii, H.; Towell, M.; Towell, R.; Towell, R. S.; Tram, V N.; Tserruya, I.; Tsuchimoto, Y.; Utsunomiya, K.; Vale, C.; Valle, H.; van Hecke, H. W.; Vargyas, M.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vértesi, R.; Vinogradov, A. A.; Virius, M.; Vossen, A.; Vrba, V.; Vznuzdaev, E.; Wang, X. R.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; Wei, R.; Wessels, J.; Whitaker, S.; White, S. N.; Winter, D.; Wolin, S.; Woody, C. L.; Wright, R. M.; Wysocki, M.; Xia, B.; Xie, W.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yamaura, K.; Yang, R.; Yanovich, A.; Ying, J.; Yokkaichi, S.; Yoo, J. S.; Yoon, I.; You, Z.; Young, G. R.; Younus, I.; Yushmanov, I. E.; Zajc, W. A.; Zaudtke, O.; Zelenski, A.; Zhang, C.; Zhou, S.; Zolin, L.

    2015-03-10

    In this study, the standard model (SM) of particle physics is spectacularly successful, yet the measured value of the muon anomalous magnetic moment (g-2)<sub>μ> deviates from SM calculations by 3.6σ. Several theoretical models attribute this to the existence of a “dark photon,” an additional U(1) gauge boson, which is weakly coupled to ordinary photons. The PHENIX experiment at the Relativistic Heavy Ion Collider has searched for a dark photon, U, in π⁰, η → γe⁺e⁻ decays and obtained upper limits of O(2×10⁻⁶) on U-γ mixing at 90% CL for the mass range 30 < m<sub>U> < 90 MeV/c². Combined with other experimental limits, the remaining region in the U-γ mixing parameter space that can explain the (g-2)<sub>μ> deviation from its SM value is nearly completely excluded at the 90% confidence level, with only a small region of 29 < m<sub>U> < 32 MeV/c² remaining.

  19. Synthesis, structural and electrical properties of [C{sub 2}H{sub 10}N{sub 2}][(SnCl(NCS){sub 2}]{sub 2}

    SciTech Connect (OSTI)

    Karoui, Sahel; Kamoun, Slaheddine; Jouini, Amor

    2013-01-15

    Synthesis, structural and electrical properties are given for a new organic stannous pseudo halide material. The structure of the [C{sub 2}H{sub 10}N{sub 2}][(SnCl(NCS){sub 2}]{sub 2} reveals that the adjacent Sn(II) centres are bridged by a pair of SCN{sup -} anions to form a 1-D array giving rise to the anionic chains (SnCl(NCS){sub 2}){sub n}{sup n-}. These chains are themselves interconnected by means of N-H Horizontal-Ellipsis Cl(S) hydrogen bonds originating from the organic cation [(NH{sub 3}){sub 2}(CH{sub 2}){sub 2}]{sup 2+}. The AC impedance measurements were performed as a function of both frequency and temperature. The electrical conduction and dielectric relaxation have been studied. The activation energy associated with the electrical relaxation determined from the electric modulus spectra was found close to that of the activation energy obtained for DC conductivity. The conduction mechanisms are attributed to the quantum mechanical tunneling model in phase I and to the proton hopping among hydrogen vacancies in phase II. - Graphical abstract: Atomic coordination in [C2H10N2][SnCl(NCS)2)2]. Highlights: Black-Right-Pointing-Pointer X-ray diffraction analysis shows the 1D network character of the structure. Black-Right-Pointing-Pointer DSC experiments show a phase transition at 336 K. Black-Right-Pointing-Pointer The AC conductivity is interpreted in terms of Jonsher's law. Black-Right-Pointing-Pointer Two conduction mechanisms are proposed for phase I and II.

  20. Role of SrMoO{sub 4} in Sr{sub 2}MgMoO{sub 6} synthesis

    SciTech Connect (OSTI)

    Vasala, S.; Yamauchi, H.; Karppinen, M.

    2011-05-15

    Here we investigate the elemental and phase compositions during the solid-state synthesis of the promising SOFC-anode material, Sr{sub 2}MgMoO{sub 6}, and demonstrate that molybdenum does not notably evaporate under the normal synthesis conditions with temperatures up to 1200 {sup o}C due to the formation of SrMoO{sub 4} as an intermediate product at low temperatures, below 600 {sup o}C. However, partial decomposition of the Sr{sub 2}MgMoO{sub 6} phase becomes evident at the higher temperatures ({approx}1500 {sup o}C). The effect of SrMoO{sub 4} on the electrical conductivity of Sr{sub 2}MgMoO{sub 6} is evaluated by preparing a series of Sr{sub 2}MgMoO{sub 6} samples with different amounts of additional SrMoO{sub 4}. Under the reducing operation conditions of an SOFC anode the insulating SrMoO{sub 4} phase is apparently reduced to the highly conductive SrMoO{sub 3} phase. Percolation takes place with 20-30 wt% of SrMoO{sub 4} in a Sr{sub 2}MgMoO{sub 6} matrix, with a notable increase in electrical conductivity after reduction. Conductivity values of 14, 60 and 160 S/cm are determined at 800 {sup o}C in 5% H{sub 2}/Ar for the Sr{sub 2}MgMoO{sub 6} samples with 30, 40 and 50 wt% of added SrMoO{sub 4}, respectively. -- Graphical abstract: SrMoO{sub 4} is formed at low temperatures during the synthesis of Sr{sub 2}MgMoO{sub 6}, which prevents the volatilization of Mo from typical precursor mixtures of this promising SOFC anode material. SrMoO{sub 4} is insulating and it is often found as an impurity in Sr{sub 2}MgMoO{sub 6} samples. It is however readily reduced to highly conducting SrMoO{sub 3}. Composites of Sr{sub 2}MgMoO{sub 6} and SrMoO{sub 3} show increased electrical conductivities compared to pure Sr{sub 2}MgMoO{sub 6} under the reductive operation conditions of an SOFC anode. Display Omitted Highlights: {yields} Sr{sub 2}MgMoO{sub 6} is a promising SOFC anode material. {yields} During the Sr{sub 2}MgMoO{sub 6} synthesis SrMoO{sub 4} is formed at low temperatures. {yields} Formation of SrMoO{sub 4} effectively prevents volatilization of Mo at high temperatures. {yields} Insulating SrMoO{sub 4} reduces to highly conductive SrMoO{sub 3} under SOFC-anode conditions. {yields} Composites of Sr{sub 2}MgMoO{sub 6} and SrMoO{sub 3} show high electrical conductivities.

  1. Sulfur dioxide gas detection with Na/sub 2/SO/sub 4/-Li/sub 2/SO/sub 4/-Y/sub 2/(SO/sub 4/)/sub 3/-SiO/sub 2/ solid electrolyte by a solid reference electrode method

    SciTech Connect (OSTI)

    Imanaka, N.; Yamaguchi, Y.; Adachi, G.; Shiokawa, J.

    1987-03-01

    The electromotive force (EMF) measurement for a Na/sub 2/SO/sub 4/Li/sub 2/SO/sub 4/-Y/sub 2/(SO/sub 4/)/sub 3/-SiO/sub 2/ solid electrolyte was performed both with NiSO/sub 4/-NiO and CoSO/sub 4/-Co/sub 3/O/sub 4/ solid reference SO/sub 2/ electrodes. The measured EMF coincided well with the calculated EMF for a sulfur dioxide gas concentration from 30 ppm to 1% at 973 K. Good agreement between the measured and calculated EMF was also obtained for the SO/sub 2/ gas content from 100 ppm to 1%, at 923 K with the NiSO/sub 4/-NiO electrode.

  2. [beta]-BaV[sub 2](P[sub 2]O[sub 7])[sub 2]: A new polymorph of barium vanadium (III) pyrophosphate characterized by intersecting tunnels

    SciTech Connect (OSTI)

    Hwu, Shiou-Jyh; Carroll, R.I.; Serra, D.L. )

    1994-06-01

    Investigation into the synthesis of reduced vanadium phosphate has led to the formation of a new form of the barium vanadium (III) pyrophosphate compound [beta]-BaV[sub 2](P[sub 2]O[sub 7])[sub 2]. It is a polymorph of the previously known BaV[sub 2](P[sub 2]O[sub 7])[sub 2], which is now labeled as the [alpha]-phase. The title compound crystallizes in the P-1 (No. 2) space group with a = 6.269 (1) [angstrom], b = 7.864 (3) [angstrom], c = 6.1592 (9) [angstrom], [alpha] = 101.34 (2)[degree], [beta] = 105.84 (1)[degree], and [gamma] = 96.51 (2)[degree]. The structure consists of corner-shared VO[sub 6] octahedra and PO[sub 4] tetrahedra that are connected in V-O-P-O-V and V-O-P-O-P-O-V bonding arrangements. This interesting three-dimensional framework is characterized by seven types of intersecting tunnels, three of which are occupied by the barium cation, while the others are empty. It is important to know that one of the empty tunnels has a relatively large window with a minimum diagonal distance of 4.4 [angstrom], which facilitates a possible framework for a lithium ion insertion reaction. The barium atom has a 10-coordination sphere, BaO[sub 10], in which the oxygen atoms can be viewed as forming two intersecting pseudohexagonal planes. [beta]-BaV[sub 2](P[sub 2]O[sub 7])[sub 2] appears to form at a relatively higher temperature than its polymorph, [alpha]-BaV[sub 2](P[sub 2]O[sub 7])[sub 2]. A detailed structural analysis and structural comparison with the [alpha]-phase, as well as a brief comparison with SrV[sub 2](P[sub 2]O[sub 7])[sub 2], are presented.

  3. A cluster with a mixed M{sub 6}X{sub 12}/M{sub 6}X{sub 8} environment: The La{sub 6}Cl{sub 11}Co structure

    SciTech Connect (OSTI)

    Zheng Chong; Mattausch, Hansjuergen; Hoch, Constantin; Simon, Arndt

    2009-08-15

    The title compound was synthesized from La, LaCl{sub 3} and Co under Ar atmosphere at 800 deg. C. It crystallizes in space group P4{sub 2}/n (no. 86) with lattice constants a=11.308(2) A and c=14.441(3) A. The structure features an isolated Co-centered La{sub 6} octahedron with all corners and edges, and 2 of its 8 triangular faces coordinated by Cl atoms. The La{sub 6}Co octahedron is significantly distorted, and the La coordination by Cl atoms deviates from the common close-packing arrangements found in other reduced rare earth metal halides. Structure, bonding and physical properties of the compound have been investigated. - Graphical abstract: La{sub 6}Cl{sub 11}Co octahedron exhibiting a mixed M{sub 6}X{sub 12}/M{sub 6}X{sub 12} coordination environment.

  4. Magnetic properties and magnetocaloric effects of Gd{sub x}Er{sub 1−x}Ga (0 ≤ x ≤ 1) compounds

    SciTech Connect (OSTI)

    Zheng, X. Q.; Wang, L. C.; Wu, R. R.; Hu, F. X.; Sun, J. R.; Shen, B. G.; Chen, J.

    2014-05-07

    We carefully studied the magnetic properties and magnetocaloric effect of Gd{sub x}Er{sub 1-x}Ga (0 ≤ x ≤ 1) compounds. The Gd{sub x}Er{sub 1-x}Ga compounds undergo two magnetic transitions with temperature increasing: spin-reorientation or antiferromagnetic-to-ferromagnetic (FM) transition and FM-to-paramagnetic transition. As the content of Gd increases from 0 to 1, the transition temperature in low temperature region changes from 15 K to 66 K and the Curie temperature increases obviously from 30 K to 181.9 K. Although the maximum value of magnetic entropy change (ΔS{sub M}) for Gd{sub x}Er{sub 1−x}Ga decreases with the increase of x, the refrigerant capacity (RC) improves remarkably compared with that of ErGa compound. Table-like ΔS{sub M} curves are observed for the compounds with x = 0.1, 0.2, 0.3, and 0.4, which are very useful for real cooling applications. And Gd{sub 0.2}Er{sub 0.8}Ga and Gd{sub 0.3}Er{sub 0.7}Ga compounds show better magnetocaloric features than others in this series under considerations of both ΔS{sub M} and RC. The results of this series of compounds show us a possible way to design and improve the magnetic refrigerant materials by making some substitutions.

  5. The Spin Structure of the Proton in the Resonance Region

    SciTech Connect (OSTI)

    Renee Fatemi

    2002-01-01

    Inclusive double spin asymmetries have been measured for {rvec p}({rvec e},e{prime}) using the CLAS detector and a polarized {sup 15}NH{sub 3} target at Jefferson Lab in 1998. The virtual photon asymmetry A{sub 1}, the longitudinal spin structure function, g{sub 1} (x, Q{sup 2}), and the first moment {Gamma}{sub 1}{sup p}, have been extracted for a Q{sup 2} range of 0.15-2.0 GeV{sup 2}. These results provide insight into the low Q{sup 2} evolution of spin dependent asymmetries and structure functions as well as the transition of {Gamma}{sub 1}{sup p} from the photon point, where the Gerasimov, Drell and Hearn Sum Rule is expected to be satisfied, to the deep inelastic region.

  6. Synthesis, crystal structure and electrical proprieties of new phosphate KCoP{sub 3}O{sub 9}

    SciTech Connect (OSTI)

    Ben Smida, Y.; Guesmi, A.; Georges, S.; Zid, M.F.

    2015-01-15

    Crystals of new tricyclophosphate KCoP{sub 3}O{sub 9} have been grown from solid state reaction and characterized by single crystal X-ray diffraction. KCoP{sub 3}O{sub 9} crystallizes in the hexagonal system, space group P6{sup ¯}c2, with a=6.616 (7) Å; c=9.788 (3) Å; V=371.06 (13) Å{sup 3}, Z=2. The final agreement factors are R=0.014, ωR=0.038, S(F{sup 2})=1.231. The structure of the title compound can be described as a three-dimensional framework built up of corner sharing CoO{sub 6} and PO{sub 4} polyhedra containing wide tunnels oriented along [001] direction and others, less broad, along [100] and [010] directions. The structural model was validated by bond valence sum (BVS) and charge distribution (CD) methods. Ball milling was used to reduce the particles sizes of the synthesized powder. At the optimal sintering temperature of 800 °C, a relative density of 85% was obtained. The microstructure was characterized by scanning electron microscopy. The electrical conductivity was 8.4×10{sup −7} S cm{sup −1} and 1.7×10{sup −4} S cm{sup −1} at 480 °C and 680 °C respectively. The activation energy deduced from the slope is 2.2 eV at low temperature region and 1.2 eV at high temperature region. The BVS model is extended to simulate the ionic migration pathways of alkali cations in the anionic framework. The BVS calculation shows one-dimensional pathways migration along c-axis. - Graphical abstract: 1D pathways link K atoms along c-axis with bond valence mismatch |ΔV(K)|=0.8 v.u. - Highlights: • A new single crystal KCoP{sub 3}O{sub 9} was grown by solid state reaction and its structure determined by single-crystal X-ray diffraction. • The purity polycrystalline of KCoP{sub 3}O{sub 9} sample was verified by Rietveld refinement. • The CIS measurements were optimized and the obtained spectra were fitted by electrical equivalent circuits. • The conduction pathways for the K{sup +} cations are simulated by means of the bond valence sum model.

  7. Proton form factor ratio, {mu}{sub p}G{sub E}{sup P}/G{sub M}{sup P} from double spin asymmetry

    SciTech Connect (OSTI)

    Habarakada Liyanage, Anusha Pushpakumari

    2013-08-01

    The form factors are fundamental properties of the nucleon representing the effect of its structure on its response to electromagnetic probes such as electrons. They are functions of the four-momentum transfer squared Q{sup 2} between the electron and the proton. This thesis reports the results of a new measurement of the ratio of the electric and magnetic form factors of the proton up to Q{sup 2} = 5.66 (GeV/c){sup 2} using the double spin asymmetry with a polarized beam and target. Experiment E07-003 (SANE, Spin Asymmetries of the Nucleon Experiment) was carried out in Hall C at Jefferson Lab in 2009 to study the proton spin structure functions with a dynamically polarized ammonia target and longitudinally polarized electron beam. By detecting elastically scattered protons in the High-Momentum Spectrometer (HMS) in coincidence with the electrons in the Big Electron Telescope Array (BETA), elastic measurements were carried out in parallel. The elastic double spin asymmetry allows one to extract the proton electric to magnetic form factor ratio G{sup p}{sub E}/G{sup p}{sub M} at high-momentum transfer, Q{sup 2} = 5.66 (GeV/c){sup 2}. In addition to the coincidence data, inclusively scattered electrons from the polarized ammonia target were detected by HMS, which allows to measure the beam-target asymmetry in the elastic region with the target spin nearly perpendicular to the momentum transfer, and to extract G{sup p}{sub E}/G{sup p}{sub M} at low Q{sup 2} = 2.06 (GeV/c){sup 2}. This alternative measurement of G{sup p}{sub E}/G{sup p}{sub M} has verified and confirmed the dramatic discrepancy at high Q{sup 2} between the Rosenbluth and the recoil-polarization-transfer iv method with a different measurement technique and systematic uncertainties uncorrelated to those of the recoil-polarization measurements. The measurement of the form factor ratio at Q{sup 2} = 2.06 (GeV/c){sup 2} has been determined as {mu}{sub p}G{sup p}{sub E}/G{sup p}{sub M} = 0.605{+-}0.178{sub stat}{+-}0.033{sub sys} which is in agreement with an earlier measurement with the polarized target technique at similar kinematics. The measurement of the form factor ratio at Q{sup 2} = 5.66 (GeV/c){sup 2} has been determined as {mu}{sub p}G{sup p}{sub E}/G{sup p}{sub M} = 0.672 {+-} 0.362{sub stat} which represents the highest Q{sup 2} reach with the double spin asymmetry to date.

  8. Thermal expansion of Cr{sub 2x}Fe{sub 2-2x}Mo{sub 3}O{sub 12}, Al{sub 2x}Fe{sub 2-2x}Mo{sub 3}O{sub 12} and Al{sub 2x}Cr{sub 2-2x}Mo{sub 3}O{sub 12} solid solutions

    SciTech Connect (OSTI)

    Ari, M.; Jardim, P.M.; Marinkovic, B.A. Rizzo, F.; Ferreira, F.F.

    2008-06-15

    The transition temperature from monoclinic to orthorhombic and the thermal expansion of the orthorhombic phase were investigated for three systems of the family A{sub 2}M{sub 3}O{sub 12}: Cr{sub 2x}Fe{sub 2-2x}Mo{sub 3}O{sub 12}, Al{sub 2x}Fe{sub 2-2x}Mo{sub 3}O{sub 12} and Al{sub 2x}Cr{sub 2-2x}Mo{sub 3}O{sub 12}. It was possible to obtain a single-phase solid solution in all studied samples (x=0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1). A linear relationship between the transition temperature and the fraction of A{sup 3+} cations (x) was observed for each system. In all orthorhombic solid solutions studied here the observed thermal expansion was anisotropic. These anisotropic thermal expansion properties of crystallographic axes a, b and c result in a low positive or near-zero overall linear coefficient of thermal expansion ({alpha}{sub l}={alpha}{sub V}/3). The relationship between the size of A{sup 3+} cations in A{sub 2}M{sub 3}O{sub 12} and the coefficient of thermal expansion is discussed. Near-zero thermal expansion of Cr{sub 2}Mo{sub 3}O{sub 12} is explained by the behavior of Cr-O and Mo-O bond distances, Cr-Mo non-bond distances and Cr-O-Mo bond angles with increasing temperature, estimated by Rietveld analysis of synchrotron X-ray powder diffraction data. - Graphical abstract: In this figure, all published overall linear coefficients of thermal expansion for orthorhombic A{sub 2}M{sub 3}O{sub 12} family obtained through diffraction methods as a function of A{sup 3+} cation radii size, together with dilatometric results, are plotted. Our results indicate that Cr{sub 2}Mo{sub 3}O{sub 12} does not exactly follow the established relationship.

  9. Symmetry determination on Pb-free piezoceramic 0.5Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}-0.5(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} using convergent beam electron diffraction method

    SciTech Connect (OSTI)

    Gao, Jinghui Zhong, Lisheng; Zhang, Lixue; Xue, Dezhen; Kimoto, Takayoshi; Song, Minghui; Ren, Xiaobing

    2014-02-07

    (1−x)(Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}-x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} (BZT-xBCT) Pb-free piezoceramic has been reported showing ultrahigh piezoelectric performance in its morphotropic phase boundary (MPB) region. However, the crystal structure characteristic for the MPB composition of BZT-xBCT is still under debate—between single orthorhombic phase and tetragonal + rhombohedral two phase mixture. In the present study, we perform the local symmetry determination on the MPB composition x = 0.5 using convergent beam electron diffraction analysis (CBED). Our CBED results from multiple zone axes suggest that there are two coexisting phases with the point group symmetries of 4 mm (tetragonal) and 3 m (rhombohedral) respectively, which agree with two phase mixture model. The strong piezoelectricity can thus be understood by considering the polarization rotation between tetragonal and rhombohedral phases by external field.

  10. Structural and thermal studies of H{sub 2}La{sub 2/3}Ta{sub 2}O{sub 7}, a protonated layered perovskite

    SciTech Connect (OSTI)

    Le Berre, F.; Crosnier-Lopez, M.P.; Fourquet, J.L.

    2006-04-13

    We have synthesised the new protonated layered perovskite H{sub 2}La{sub 2/3}Ta{sub 2}O{sub 7} which is related to the Ruddlesden-Popper family. This compound is obtained by ionic exchange starting from Li{sub 2}La{sub 2/3}Ta{sub 2}O{sub 7} maintained in dilute HNO{sub 3} at 60 deg. C. Thermal X-ray diffraction and DTA/TGA revealed interesting dehydration properties with formation of a layered anhydrous phase leading at higher temperature (1550 deg. C) to La{sub 1/3}TaO{sub 3}. This latter compound exhibits the original lanthanum ordering expected similarly to that of the Li form, while at 900 deg. C a metastable form, presenting a disordered La distribution, is observed.

  11. Kinetic study of hydrogen evolution reaction on Ni{sub 30} Mo{sub 70}, Co{sub 30}Mo{sub 70}, Co{sub 30}Ni{sub 70} and Co{sub 10}Ni{sub 20}Mo{sub 70} alloy electrodes

    SciTech Connect (OSTI)

    Dominguez-Crespo, M.A.; Plata-Torres, M.; Torres-Huerta, A.M.; Arce-Estrada, E.M. . E-mail: earce@ipn.mx; Hallen-Lopez, J.M.

    2005-07-15

    The hydrogen evolution reaction on nanocrystalline Ni{sub 30}Mo{sub 70}, Co{sub 30}Mo{sub 70}, Co{sub 30}Ni{sub 70}, and Co{sub 10}Ni{sub 20}Mo{sub 70}, metallic powders prepared by mechanical alloying was investigated with linear polarization and ac impedance methods, in 30 wt.% KOH aqueous solution at room temperature. The formation process and structural properties of these nanocrystalline materials were characterized by X-ray diffraction and transmission electron microscopy. Alloyed powders showed the presence of two phases: an fcc solid solution and intermetallic compounds of Ni, Co and Mo. Based on polarization and ac impedance measurements, an improved electrocatalytic activity for hydrogen evolution reaction was observed in mechanically alloyed Co{sub 30}Ni{sub 70} powders, which is slightly higher than milled metallic Ni powders.

  12. CuYb{sub 2}Ge{sub 4}O{sub 12}, a new bidimensionally tunneled structure

    SciTech Connect (OSTI)

    Campa, J.A.; Cascales, C.; Gueierrez-Puebla, E.; Monge, M.A.; Rasines, I.; Ruiz Valero, C.

    1996-06-01

    Employing CuO as self flux crystals of CuYb{sub 2}Ge{sub 4}O{sub 12} have been grown for the first time. The crystal structure of CuYb{sub 2}Ge{sub 4}O{sub 12} has been determined by single-crystal X-ray diffraction in the triclinic P1 (No. 2) space group to an R value of 6.1%, with (a) = 7.156(2) {Angstrom}, (b) = 7.937(3) {Angstrom}, (c) = 4.905(3) {Angstrom}, {alpha} = 86.63(3){degrees}, {Beta} = 102.41(4){degrees}, {gamma}=1114.12(3){degrees}, V = 248.2(2) {Angstrom}{sup 3}, Z = 1, and D{sub c} = 5.97 gcm{sup {minus}3}. The novel tridimensional CuYb{sub 2}Ge{sub 4}O{sub 12} structure type can be conceived as formed by layers of (GeO{sub 4}){sub 4} units of vertex-sharing GeO{sub 4} squares connecting (GeO{sub 4}){sub 4} units, with channels or tunnels of size up to 4.08 {Angstrom} in the a and c directions. A comparison is made between the structure types of the title germanate and recently reported CuNd{sub 2}Ge{sub 2}O{sub 8}. The temperature dependence from 350 to 1.8 K of the reciprocal dc magnetic susceptibility for CuYb{sub 2}Ge{sub 4}O{sub 12} is shown and presents a deviation from linearity over the whole temperature range. The infrared spectrum between 1000 and 100 cm{sup {minus}1} is given and related with those of comparable species.

  13. Alternative current conduction mechanisms of organic-inorganic compound [N(CH{sub 3}){sub 3}H]{sub 2}ZnCl{sub 4}

    SciTech Connect (OSTI)

    Ben Bechir, M. Karoui, K.; Guidara, K.; Ben Rhaiem, A.; Tabellout, M.

    2014-04-21

    [N(CH{sub 3}){sub 3}H]{sub 2}ZnCl{sub 4} has been studied by X-ray powder diffraction patterns, differential scanning calorimetry (DSC), and impedance spectroscopy. The [N(CH{sub 3}){sub 3}H]{sub 2}ZnCl{sub 4} hybrid compound is crystallized at room temperature (T ? 300?K) in the orthorhombic system with Pnma space group. Five phase transitions (T{sub 1}?=?255?K, T{sub 2}?=?282?K, T{sub 3}?=?302?K, T{sub 4}?=?320?K, and T{sub 5}?=?346?K) have been proved by DSC measurements. The electrical technique was measured in the 10{sup ?1}-10{sup 7}?Hz frequency range and 233363?K temperature interval. The frequency dependence of alternative current (AC) conductivity is interpreted in terms of Jonscher's law. The AC electrical conduction in [N(CH{sub 3}){sub 3}H]{sub 2}ZnCl{sub 4} is analyzed by different processes, which can be attributed to several models: the correlated barrier hopping model in phase I, the overlapping large polaron tunneling model in phase II, the quantum mechanical tunneling model in phase IV, and the non-overlapping small polaron tunneling model in phases III, V, and VI. The conduction mechanism is studied with the help of Elliot's theory, and the Elliot's parameters are determined.

  14. Alternative current conduction mechanisms of organic-inorganic compound [N(CH{sub 3}){sub 3}H]{sub 2}CuCl{sub 4}

    SciTech Connect (OSTI)

    Ben Bechir, M. Karoui, K.; Guidara, K.; Ben Rhaiem, A.; Tabellout, M.

    2014-05-28

    The [N(CH{sub 3}){sub 3}H]{sub 2}CuCl{sub 4} single crystal has been analyzed by X-ray powder diffraction patterns, differential scanning calorimetry (DSC), and electrical impedance spectroscopy. [N(CH{sub 3}){sub 3}H]{sub 2}CuCl{sub 4} crystallizes at room temperature in the monoclinic system with P2{sub 1}/{sub C} space group. Three phase transitions at T{sub 1}?=?226?K, T{sub 2}?=?264?K, and T{sub 3}?=?297?K have been evidenced by DSC measurements. The electrical technique was measured in the 10{sup ?1}10{sup 7}?Hz frequency range and 203313?K temperature intervals. The frequency dependence of alternative current (AC) conductivity is interpreted in terms of Jonscher's law (developed). The AC electrical conduction in [N(CH{sub 3}){sub 3}H]{sub 2}CuCl{sub 4} compound is studied by two processes which can be attributed to a hopping transport mechanism: the correlated barrier hopping model in phases I, II, and III, the non-overlapping small polaron tunneling model in phase IV. The conduction mechanism is interpreted with the help of Elliot's theory, and the Elliot's parameters are found.

  15. Crystal-chemistry of mullite-type aluminoborates Al{sub 18}B{sub 4}O{sub 33} and Al{sub 5}BO{sub 9}: A stoichiometry puzzle

    SciTech Connect (OSTI)

    Fisch, Martin; Armbruster, Thomas; Rentsch, Daniel; Libowitzky, Eugen; Pettke, Thomas

    2011-01-15

    Orthorhombic Al{sub 2}O{sub 3}-rich aluminoborate is an important ceramic material for which two slightly different compositions have been assumed: Al{sub 5}BO{sub 9} (5Al{sub 2}O{sub 3}:B{sub 2}O{sub 3}) and Al{sub 18}B{sub 4}O{sub 33} (9Al{sub 2}O{sub 3}:2B{sub 2}O{sub 3}). The formula Al{sub 18}B{sub 4}O{sub 33} (=Al{sub 4.91}B{sub 1.09}O{sub 9}) was derived from results of chemical analyses when crystal structure data were not yet available. Subsequent structural investigations indicated Al{sub 5}BO{sub 9} composition. Nevertheless, Al{sub 18}B{sub 4}O{sub 33} was still accepted as the correct stoichiometry assuming that additional B replaces 9% Al. Powder samples of both compositions and ones with excess boron were prepared by solid state reactions between {alpha}-Al{sub 2}O{sub 3} and B{sub 2}O{sub 3}/H{sub 3}BO{sub 3} at temperatures above 1100 {sup o}C and single-crystals were grown from flux at 1100 and 1550 {sup o}C. Products were investigated by single-crystal and powder XRD, {sup 11}B and {sup 27}Al solid-state MAS-NMR, Raman and FTIR spectroscopy as well as Laser-ablation ICP-MS. No indication of the predicted 9% B{yields}Al substitution was found. LA ICP-MS indicated 12.36(27) wt% B{sub 2}O{sub 3} corresponding to Al{sub 4.97}B{sub 1.03}O{sub 9}. Hence, the suggested Al{sub 18}B{sub 4}O{sub 33} stoichiometry can be excluded for all synthesized samples. A very low amount of Al vacancies at a five-fold coordinated site are likely, charge balanced by an additional nearby three-fold coordinated B site. All evidences indicate that the title compound should be reported as Al{sub 5-x}B{sub 1+x}O{sub 9} with x<0.038(6), which is close to Al{sub 5}BO{sub 9}. -- Graphical abstract: A chemical composition of Al{sub 18}B{sub 4}O{sub 33}=Al{sub 4.91}B{sub 1.09}O{sub 9}=9Al{sub 2}O{sub 3}:2B{sub 2}O{sub 3} has been assumed for mullite-type aluminoborate with Al{sub 5}BO{sub 9} structure. However, samples prepared by different routes showed compositions close to 5Al{sub 2}O{sub 3}:B{sub 2}O{sub 3}. Display Omitted

  16. Crystal structures and compressibility of novel iron borides Fe{sub 2}B{sub

    Office of Scientific and Technical Information (OSTI)

    7} and Fe{sub x}B{sub 50} synthesized at high pressure and high temperature (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Crystal structures and compressibility of novel iron borides Fe{sub 2}B{sub 7} and Fe{sub x}B{sub 50} synthesized at high pressure and high temperature Citation Details In-Document Search Title: Crystal structures and compressibility of novel iron borides Fe{sub 2}B{sub 7} and Fe{sub x}B{sub 50} synthesized at high pressure and high

  17. Structure and magnetic interactions in the solid solution Ba{sub 3?x}Sr{sub x}Cr{sub 2}O{sub 8}

    SciTech Connect (OSTI)

    Grundmann, Henrik; Schilling, Andreas; Marjerrison, Casey A.; Dabkowska, Hanna A.; Gaulin, Bruce D.

    2013-09-01

    Highlights: We describe for the first time the preparation of single- and polycrystalline members of the solid solution Ba{sub 3?x}Sr{sub x}Cr{sub 2}O{sub 8}. We report on the structural changes in the solid solution at room temperature depending on the stoichiometry. We describe the peculiar change of the magnetic behavior in the solid solution with the stoichiometry. - Abstract: Solid solutions of the magnetic insulators Ba{sub 3}Cr{sub 2}O{sub 8} and Sr{sub 3}Cr{sub 2}O{sub 8} (Ba{sub 3?x}Sr{sub x}Cr{sub 2}O{sub 8}) have been prepared in polycrystalline form for the first time. Single crystalline material was obtained using a mirror image floating zone technique. X-ray diffraction data taken at room temperature indicate that the space group of Ba{sub 3?x}Sr{sub x}Cr{sub 2}O{sub 8} remains unchanged for all values of x, while the cell parameters depend on the chemical composition, as expected. Magnetization data, measured from 300 K down to 2 K, suggest that the interaction constant J{sub d} within the Cr{sup 5+} dimers varies in a peculiar way as a function of x, starting at J{sub d} = 25 K for x = 0, then first slightly dropping to J{sub d} = 18 K for x ? 0.75, before reaching J{sub d} = 62 K for x = 3.

  18. Synthesis, crystal structure, spectroscopic and thermal properties of [Et{sub 4}N][Ta{sub 6}Br{sub 12}(H{sub 2}O){sub 6}]Br{sub 4}.4H{sub 2}O (Et=ethyl)-A new compound with the paramagnetic [Ta{sub 6}Br{sub 12}]{sup 3+} cluster core

    SciTech Connect (OSTI)

    Peric, Berislav; Jozic, Drazan; Planinic, Pavica; Brnicevic, Nevenka; Giester, Gerald

    2009-09-15

    A new hexanuclear cluster compound, [Et{sub 4}N][Ta{sub 6}Br{sub 12}(H{sub 2}O){sub 6}]Br{sub 4}.4H{sub 2}O (Et=ethyl) (1), with the paramagnetic [Ta{sub 6}Br{sub 12}]{sup 3+} cluster entity, was synthesized and characterized by elemental and TG/DTA analyses, IR and UV/Vis spectroscopy and by a single-crystal X-ray diffraction study. The presence of the paramagnetic [Ta{sub 6}Br{sub 12}]{sup 3+} unit was confirmed also by the room-temperature magnetic and EPR measurements. The compound crystallizes in the tetragonal I4{sub 1}/a space group, with a=14.299(5), c=21.241(5) A, Z=4, R{sub 1}(F)/wR{sub 2}(F{sup 2})=0.0296/0.0811. The structure contains discrete [Ta{sub 6}Br{sub 12}(H{sub 2}O){sub 6}]{sup 3+} cations with an octahedron of metal atoms edge-bridged by bromine atoms and with water molecules occupying all six terminal positions. The cluster units are positioned in the vertices of the three-dimensional (pseudo)diamond lattice. The structure shows similarities with literature reported structures of cluster compounds crystallizing in the diamond (Fd3-barm) space group. - Graphical abstract: Two interpenetrating (pseudo)diamond nets formed by packing of the paramagnetic [Ta{sub 6}Br{sub 12}(H{sub 2}O)]{sup 3+} (octahedral) and diamagnetic [Et{sub 4}N]{sup +} (spheres) cations.

  19. Synthesis, magnetic and dielectric characterization of nanocrystalline solid solutions of In{sub 2−x}Ni{sub x}O{sub 3} (x = 0.05, 0.10 and 0.15)

    SciTech Connect (OSTI)

    Ahmad, Tokeer; Khatoon, Sarvari; Coolahan, Kelsey

    2013-09-01

    Graphical abstract: Monophasic and crystalline In{sub 2−x}Ni{sub x}O{sub 3} nanoparticles of size 8–15 nm have been synthesized solvothermally and showed red shift in energy band gap which decreases on increasing Ni{sup 2+} concentration in In{sub 2}O{sub 3} host lattice. - Highlights: • Monophasic Ni-doped In{sub 2}O{sub 3} nanoparticles by solvothermal method for first time. • Plausible reaction mechanism using thermogravimetric analysis. • High surface area with small particle size obtained. • Solid solutions exhibit paramagnetism with very weak antiferromagnetic interactions. - Abstract: In{sub 2−x}Ni{sub x}O{sub 3} (x = 0.05, 0.10 and 0.15) nanoparticles were successfully synthesized by solvothermal method by the thermal decomposition of oxalate precursor at 450 °C for the first time. X-ray diffraction studies showed the formation of highly crystalline and monophasic cubic structure of In{sub 2}O{sub 3} which is attributed to the formation of solid solution. These nanoparticles show good optical transmittance in the visible region. Optical measurements showed an energy band gap which decreases with increasing Ni concentration. The grain size decreases from 15 nm to 8 nm and surface area increases from 90 to 254 m{sup 2} g{sup −1} on increasing the Ni concentration. High dielectric constant and dielectric loss has been obtained which indicates the conducting nature of these solid solutions. Magnetic measurements showed that the samples are strong paramagnetic in nature with very weak antiferromagnetic interactions. No evidence of ferromagnetism is observed for these solid solutions at room temperature.

  20. NASEO Midwest Regional Meeting

    Broader source: Energy.gov [DOE]

    The National Association of State Energy Officials (NASEO) is hosting its Midwest Regional Meeting in Des Moines, Iowa.

  1. Regional Education Partners

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Regional Education Partners Regional Education Partners One of the Laboratory's STEM education objectives is centered on strengthening the future workforce of Northern New Mexico and LANL through effective partnerships with regional secondary and higher education organizations, businesses and industry. Contact Executive Office Director Kathy Keith Community Relations & Partnerships (505) 665-4400 Email Regional Partners Charlie McMillan talking with Rick Ulibarri and Dr. Fries, President of

  2. H{sub 2}CO AND N{sub 2}H{sup +} IN PROTOPLANETARY DISKS: EVIDENCE FOR A CO-ICE REGULATED CHEMISTRY

    SciTech Connect (OSTI)

    Qi, Chunhua; Wilner, David J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Oeberg, Karin I. [Departments of Chemistry and Astronomy, University of Virginia, Charlottesville, VA 22904 (United States)] [Departments of Chemistry and Astronomy, University of Virginia, Charlottesville, VA 22904 (United States)

    2013-03-01

    We present Submillimeter Array (SMA) observations of H{sub 2}CO and N{sub 2}H{sup +} emission in the disks around the T Tauri star TW Hya and the Herbig Ae star HD 163296 at 2''-6'' resolution and discuss the distribution of these species with respect to CO freezeout. The H{sub 2}CO and N{sub 2}H{sup +} emission toward HD 163296 does not peak at the continuum emission center that marks the stellar position but is instead significantly offset. Using a previously developed model for the physical structure of this disk, we show that the H{sub 2}CO observations are reproduced if H{sub 2}CO is present predominantly in the cold outer disk regions. A model where H{sub 2}CO is present only beyond the CO snow line (estimated at a radius of 160 AU) matches the observations well. We also show that the average H{sub 2}CO excitation temperature, calculated from two transitions of H{sub 2}CO observed in these two disks and a larger sample of disks around T Tauri stars in the DISCS (the Disk Imaging Survey of Chemistry with SMA) program, is consistent with the CO freezeout temperature of {approx}20 K. In addition, we show that N{sub 2}H{sup +} and H{sub 2}CO line fluxes in disks are strongly correlated, indicative of co-formation of these species across the sample. Taken together, these results imply that H{sub 2}CO and N{sub 2}H{sup +} are generally present in disks only at low temperatures where CO depletes onto grains, consistent with fast destruction of N{sub 2}H{sup +} by gas-phase CO, and in situ formation of H{sub 2}CO through hydrogenation of CO ice. In this scenario H{sub 2}CO, CH{sub 3}OH, and N{sub 2}H{sup +} emission in disks should appear as rings with the inner edge at the CO midplane snow line. This prediction can be tested directly using observations from ALMA with higher resolution and better sensitivity.

  3. GeO{sub 2}/Ge structure submitted to annealing in deuterium: Incorporation pathways and associated oxide modifications

    SciTech Connect (OSTI)

    Bom, N. M.; Soares, G. V.; Hartmann, S.; Bordin, A.; Radtke, C.

    2014-10-06

    Deuterium (D) incorporation in GeO{sub 2}/Ge structures following D{sub 2} annealing was investigated. Higher D concentrations were obtained for GeO{sub 2}/Ge samples in comparison to their SiO{sub 2}/Si counterparts annealed in the same conditions. Oxygen vacancies produced during the annealing step in D{sub 2} constitute defect sites for D incorporation, analogous to defects at the SiO{sub 2}/Si interfacial region. Besides D incorporation, volatilization of the oxide layer is also observed as a consequence of D{sub 2} annealing, especially in the high temperature regime of the present study (>450?C). In parallel to this volatilization, the stoichiometry and chemical structure of remnant oxide are modified as well. These results evidence the broader impact of forming gas annealing in dielectric/Ge structures with respect to SiO{sub 2}/Si counterparts.

  4. Visible light photocatalytic degradation of 4-chlorophenol using vanadium and nitrogen co-doped TiO{sub 2}

    SciTech Connect (OSTI)

    Jaiswal, R.; Kothari, D. C.; Patel, N.; Miotello, A.

    2013-02-05

    Vanadium and Nitrogen were codoped in TiO{sub 2} photocatalyst by Sol-gel method to utilize visible light more efficiently for photocatalytic reactions. A noticeable shift of absorption edge to visible light region was obtained for the singly-doped namely V-TiO{sub 2}, N-TiO{sub 2} and codoped V-N-TiO{sub 2} samples in comparison with undoped TiO{sub 2}, with smallest band gap obtained with codoped-TiO{sub 2}. The photocatalytic activities for all TiO{sub 2} photocatalysts were tested by 4-chlorophenol (organic pollutant) degradation under visible light irradiation. It was found that codoped TiO{sub 2} exhibits the best photocatalytic activity, which could be attributed to the synergistic effect produced by V and N dopants.

  5. CO<sub>2sub> Storage by Sorption on Organic Matter and Clay in Gas Shale

    SciTech Connect (OSTI)

    Bacon, Diana H.; Yonkofski, Catherine MR; Schaef, Herbert T.; White, Mark D.; McGrail, B. Peter

    2015-10-10

    Simulations of methane production and supercritical carbon dioxide injection were developed that consider competitive adsorption of CH<sub>4sub> and CO<sub>2sub> on both organic matter and montmorillonite. The results were used to assess the potential for storage of CO<sub>2sub> in a hydraulically fractured shale gas reservoir and for enhanced recovery of CH<sub>4sub>. Assuming equal volume fractions of organic matter and montmorillonite, amounts of CO<sub>2sub> adsorbed on both materials were comparable, while methane desorption was from clays was two times greater than desorption from organic material. The most successful strategy considered CO<sub>2sub> injection from a separate well and enhanced methane recovery by 73%, while storing 240 kmt of CO<sub>2sub>.

  6. K{sub 2}NaOsO{sub 5.5} and K{sub 3}NaOs{sub 2}O{sub 9}: The first osmium perovskites containing alkali cations at the 'A' site

    SciTech Connect (OSTI)

    Mogare, Kailash M.; Klein, Wilhelm; Jansen, Martin

    2012-07-15

    K{sub 2}NaOsO{sub 5.5} and K{sub 3}NaOs{sub 2}O{sub 9} were obtained from solid-state reactions of potassium superoxide, sodium peroxide and osmium metal at elevated oxygen pressures. K{sub 2}NaOsO{sub 5.5} crystallizes as an oxygen-deficient cubic double perovskite in space group Fm3{sup Macron }m with a=8.4184(5) A and contains isolated OsO{sub 6} octahedra. K{sub 3}NaOs{sub 2}O{sub 9} crystallizes hexagonally in P6{sub 3}/mmc with a=5.9998(4) A and c=14.3053(14) A. K{sub 3}NaOs{sub 2}O{sub 9} consists of face sharing Os{sub 2}O{sub 9} pairs of octahedra. According to magnetic measurements K{sub 2}NaOsO{sub 5.5} is diamagnetic, whereas K{sub 3}NaOs{sub 2}O{sub 9} displays strong antiferromagnetic coupling (T{sub N}=140 K), indicating enhanced magnetic interactions within the octahedral pair. - Graphical abstract: High oxidation states of Os, obtained by high oxygen pressure synthesis, are accommodated in double and triple perovskite matrices. K{sub 3}NaOs{sub 2}O{sub 9} displays enhanced magnetic interactions. Highlights: Black-Right-Pointing-Pointer New osmates containing highly oxidized Os were obtained by high O{sub 2} pressure synthesis. Black-Right-Pointing-Pointer High oxidation states of Os are accommodated in double and triple perovskite matrices. Black-Right-Pointing-Pointer Both compounds represent the first Os perovskites with an alkali metal at the A site. Black-Right-Pointing-Pointer K{sub 3}NaOs{sub 2}O{sub 9} displays enhanced magnetic interactions within the octahedral pair.

  7. Pressure effects on magnetic pair-breaking in Mn- and Eu-substituted BaFe{sub 2}As{sub 2}

    SciTech Connect (OSTI)

    Rosa, P. F. S.; Garitezi, T. M.; Adriano, C.; Urbano, R. R.; Pagliuso, P. G.; Grant, T.; Fisk, Z.; Fernandes, R. M.

    2014-05-07

    We report a combined study of hydrostatic pressure (P ? 25 kbar) and chemical substitution on the magnetic pair-breaking effect in Eu- and Mn-substituted BaFe{sub 2}As{sub 2} single crystals. At ambient pressure, both substitutions suppress the superconducting (SC) transition temperature (T{sub c}) of BaFe{sub 2x}Co{sub x}As{sub 2} samples slightly under the optimally doped region, indicating the presence of a pair-breaking effect. At low pressures, an increase of T{sub c} is observed for all studied compounds followed by an expected decrease at higher pressures. However, in the Eu dilute system, T{sub c} further increases at higher pressure along with a narrowing of the SC transition, suggesting that a pair-breaking mechanism reminiscent of the Eu Kondo single impurity regime is being suppressed by pressure. Furthermore, Electron Spin Resonance (ESR) measurements indicate the presence of Mn{sup 2+} and Eu{sup 2+} local moments and the microscopic parameters extracted from the ESR analysis reveal that the AbrikosovGor'kov expression for magnetic pair-breaking in a conventional sign-preserving superconducting state cannot describe the observed reduction of T{sub c}.

  8. Silicon etch using SF{sub 6}/C{sub 4}F{sub 8}/Ar gas mixtures

    SciTech Connect (OSTI)

    Bates, Robert L.; Stephan Thamban, P. L.; Goeckner, Matthew J.; Overzet, Lawrence J.

    2014-07-01

    While plasmas using mixtures of SF{sub 6}, C{sub 4}F{sub 8}, and Ar are widely used in deep silicon etching, very few studies have linked the discharge parameters to etching results. The authors form such linkages in this report. The authors measured the optical emission intensities of lines from Ar, F, S, SF{sub x}, CF{sub 2}, C{sub 2}, C{sub 3}, and CS as a function of the percentage C{sub 4}F{sub 8} in the gas flow, the total gas flow rate, and the bias power. In addition, the ion current density and electron temperature were measured using a floating Langmuir probe. For comparison, trenches were etched of various widths and the trench profiles (etch depth, undercut) were measured. The addition of C{sub 4}F{sub 8} to an SF{sub 6}/Ar plasma acts to reduce the availability of F as well as increase the deposition of passivation film. Sulfur combines with carbon in the plasma efficiently to create a large optical emission of CS and suppress optical emissions from C{sub 2} and C{sub 3}. At low fractional flows of C{sub 4}F{sub 8}, the etch process appears to be controlled by the ion flux more so than by the F density. At large C{sub 4}F{sub 8} fractional flows, the etch process appears to be controlled more by the F density than by the ion flux or deposition rate of passivation film. CF{sub 2} and C{sub 2} do not appear to cause deposition from the plasma, but CS and other carbon containing molecules as well as ions do.

  9. CO/H{sub 2} abundance ratio ? 10{sup 4} in a protoplanetary disk

    SciTech Connect (OSTI)

    France, Kevin; McJunkin, Matthew; Herczeg, Gregory J.; Penton, Steven V.

    2014-10-20

    The relative abundances of atomic and molecular species in planet-forming disks around young stars provide important constraints on photochemical disk models and provide a baseline for calculating disk masses from measurements of trace species. A knowledge of absolute abundances, those relative to molecular hydrogen (H{sub 2}), are challenging because of the weak rovibrational transition ladder of H{sub 2} and the inability to spatially resolve different emission components within the circumstellar environment. To address both of these issues, we present new contemporaneous measurements of CO and H{sub 2} absorption through the 'warm molecular layer' of the protoplanetary disk around the Classical T Tauri Star RW Aurigae A. We use a newly commissioned observing mode of the Hubble Space Telescope Cosmic Origins Spectrograph to detect warm H{sub 2} absorption in this region for the first time. An analysis of the emission and absorption spectrum of RW Aur shows components from the accretion region near the stellar photosphere, the molecular disk, and several outflow components. The warm H{sub 2} and CO absorption lines are consistent with a disk origin. We model the 1092-1117 spectrum of RW Aur to derive log{sub 10} N(H{sub 2}) = 19.90{sub ?0.22}{sup +0.33} cm{sup 2} at T {sub rot}(H{sub 2}) = 440 39 K. The CO A - X bands observed from 1410 to 1520 are best fit by log{sub 10} N(CO) = 16.1 {sub ?0.5}{sup +0.3} cm{sup 2} at T {sub rot}(CO) = 200{sub ?125}{sup +650} K. Combining direct measurements of the H I, H{sub 2}, and CO column densities, we find a molecular fraction in the warm disk surface of f {sub H2} ? 0.47 and derive a molecular abundance ratio of CO/H{sub 2} = 1.6{sub ?1.3}{sup +4.7} 10{sup 4}, both consistent with canonical interstellar dense cloud values.

  10. A novel technique for measurement of thermal rate constants and temperature dependences of dissociative recombination: CO{sub 2}{sup +}, CF{sub 3}{sup +}, N{sub 2}O{sup +}, C{sub 7}H{sub 8}{sup +}, C{sub 7}H{sub 7}{sup +}, C{sub 6}H{sub 6}{sup +}, C{sub 6}H{sub 5}{sup +}, C{sub 5}H{sub 6}{sup +}, C{sub 4}H{sub 4}{sup +}, and C{sub 3}H{sub 3}{sup +}

    SciTech Connect (OSTI)

    Fournier, Joseph A.; Shuman, Nicholas S.; Melko, Joshua J.; Ard, Shaun G.; Viggiano, Albert A.

    2013-04-21

    A novel technique using a flowing afterglow-Langmuir probe apparatus for measurement of temperature dependences of rate constants for dissociative recombination (DR) is presented. Low ({approx}10{sup 11} cm{sup -3}) concentrations of a neutral precursor are added to a noble gas/electron afterglow plasma thermalized at 300-500 K. Charge exchange yields one or many cation species, each of which may undergo DR. Relative ion concentrations are monitored at a fixed reaction time while the initial plasma density is varied between 10{sup 9} and 10{sup 10} cm{sup -3}. Modeling of the decrease in concentration of each cation relative to the non-recombining noble gas cation yields the rate constant for DR. The technique is applied to several species (O{sub 2}{sup +}, CO{sub 2}{sup +}, CF{sub 3}{sup +}, N{sub 2}O{sup +}) with previously determined 300 K values, showing excellent agreement. The measurements of those species are extended to 500 K, with good agreement to literature values where they exist. Measurements are also made for a range of C{sub n}H{sub m}{sup +} (C{sub 7}H{sub 7}{sup +}, C{sub 7}H{sub 8}{sup +}, C{sub 5}H{sub 6}{sup +}, C{sub 4}H{sub 4}{sup +}, C{sub 6}H{sub 5}{sup +}, C{sub 3}H{sub 3}{sup +}, and C{sub 6}H{sub 6}{sup +}) derived from benzene and toluene neutral precursors. C{sub n}H{sub m}{sup +} DR rate constants vary from 8-12 Multiplication-Sign 10{sup -7} cm{sup 3} s{sup -1} at 300 K with temperature dependences of approximately T{sup -0.7}. Where prior measurements exist these results are in agreement, with the exception of C{sub 3}H{sub 3}{sup +} where the present results disagree with a previously reported flat temperature dependence.

  11. Nuclear and magnetic supercells in the multiferroic candidate: Pb{sub 3}TeMn{sub 3}P{sub 2}O{sub 14}

    SciTech Connect (OSTI)

    Silverstein, Harlyn J.; Huq, Ashfia; Lee, Minseong; Choi, Eun Sang; Zhou, Haidong; Wiebe, Christopher R.

    2015-01-15

    The dugganites, Te{sup 6+}-containing members of the langasite series, have attracted recent interest due to their complex low-temperature magnetic unit cells, magnetodielectric, and potentially multiferroic properties. For Pb{sup 2+}-containing dugganites, a large monoclinic supercell was reported and was found to have a profound effect on the low temperature magnetism and spin excitation spectra. Pb{sub 3}TeMn{sub 3}P{sub 2}O{sub 14} is another dugganite previously shown to distort away from the canonical P321 langasite unit cell, although this supercell was never fully solved. Here we report the full crystal and magnetic structure solution of Pb{sub 3}TeMn{sub 3}P{sub 2}O{sub 14} using synchrotron x-ray and neutron diffraction data: a large trigonal supercell is observed in this material, which is believed to be the first supercell of its kind in the langasite family. Here, the magnetic structure, high-magnetic field behavior, and dielectric properties of Pb{sub 3}TeMn{sub 3}P{sub 2}O{sub 14} are presented. In addition to showing weak magnetoelectric behavior similar to other langasites, it was found that a phase transition occurs at 3 T near the antiferromagnetic transition temperature. - Graphical abstract: The nuclear supercell of Pb{sub 3}TeMn{sub 3}P{sub 2}O{sub 14}, found through joint refinements using high resolution synchrotron X-ray and neutron powder diffraction, retains the trigonal symmetry of the subcell. - Highlights: • Large P3 supercell found in Pb{sub 3}TeMn{sub 3}P{sub 2}O{sub 14}. • Complex helical spin structures below T{sub N}=6.6 K. • Phase transition at 3 T found using through dielectric and DC susceptibility measurements. • Moment saturation near 25 T at 1.4 K.

  12. Magnetic excitations in the spin-1/2 triangular-lattice antiferromagnet Cs<sub>2sub>CuBr>4sub>

    SciTech Connect (OSTI)

    Zvyagin, S. A.; Ozerov, M.; Kamenskyi, D.; Wosnitza, J.; Krzystek, J.; Yoshizawa, D.; Hagiwara, M.; Hu, Rongwei; Ryu, Hyejin; Petrovic, C.; Zhitomirsky, M. E.

    2015-11-27

    We present on high- field electron spin resonance (ESR) studies of magnetic excitations in the spin- 1/2 triangular-lattice antiferromagnet Cs<sub>2sub>CuBr>4sub>. Frequency- field diagrams of ESR excitations are measured for different orientations of magnetic fields up to 25 T. We show that the substantial zero- field energy gap, Δ ≈ 9.5 K, observed in the low-temperature excitation spectrum of Cs<sub>2sub>CuBr>4sub> [Zvyagin et al:, Phys. Rev. Lett. 112, 077206 (2014)], is present well above T<sub>N>. Noticeably, the transition into the long-range magnetically ordered phase does not significantly affect the size of the gap, suggesting that even below T<sub>N> the high-energy spin dynamics in Cs<sub>2sub>CuBr>4sub> is determined by short-range-order spin correlations. The experimental data are compared with results of model spin-wave-theory calculations for spin-1/2 triangle-lattice antiferromagnet.

  13. Electronic structure and optical properties of ?-(Fe{sub 1-x}V{sub x}){sub 2}O{sub 3} solid-solution thin films

    SciTech Connect (OSTI)

    Chamberlin, S. E.; Nayyar, I. H.; Kaspar, T. C.; Sushko, P. V.; Chambers, S. A.

    2015-01-26

    We have examined the effect of V doping on the electronic and optical properties of epitaxial hematite (?-Fe{sub 2}O{sub 3}) thin films, by employing several characterization techniques and computational modeling. The conductivity of ?-(Fe{sub 1-x}V{sub x}){sub 2}O{sub 3} (0???x????0.5) is enhanced by several orders of magnitude as x is increased, as evidenced by electrical resistivity measurements and x-ray photoelectron spectroscopy core-level and valence-band spectra. Optical absorption shows a reduction in the direct band gap by as much as 0.64?eV for x?=?0.53 (E{sub g}?=?1.46?eV) relative to that of ?-Fe{sub 2}O{sub 3} (E{sub g}?=?2.10?eV). Detailed understanding of the character of the optical transitions in the alloys is achieved using first-principles calculations of the ground and excited states. These calculations reveal that V doping results in occupied V 3d orbitals hybridized with Fe orbitals and located at approximately mid-gap in ?-Fe{sub 2}O{sub 3}. The lowest energy transitions involve charge transfer from occupied V 3d to unoccupied Fe 3d* orbitals. With a low band gap and high conductivity, ?-(Fe{sub 1-x}V{sub x}){sub 2}O{sub 3} is a promising material for photovoltaic and photoelectrochemical applications.

  14. Development of epitaxial Al<sub>xSc>1-xsub>N for artificially structured metal/semiconductor superlattice metamaterials

    SciTech Connect (OSTI)

    Sands, Timothy D.; Stach, Eric A.; Saha, Bivas; Saber, Sammy; Naik, Gururaj V.; Boltasseva, Alexandra; Kvam, Eric P.

    2015-02-01

    Epitaxial nitride rocksalt metal/semiconductor superlattices are emerging as a novel class of artificially structured materials that have generated significant interest in recent years for their potential application in plasmonic and thermoelectric devices. Though most nitride metals are rocksalt, nitride semiconductors in general have hexagonal crystal structure. We report rocksalt aluminum scandium nitride (Al,Sc)N alloys as the semiconducting component in epitaxial rocksalt metal/semiconductor superlattices. The Al<sub>xSc>1-xsub>N alloys when deposited directly on MgO substrates are stabilized in a homogeneous rocksalt (single) phase when x < 0.51. Employing 20 nm TiN as a seed layer on MgO substrates, the homogeneity range for stabilizing the rocksalt phase has been extended to x < 0.82 for a 120 nm film. The rocksalt Al<sub>xSc>1-xsub>N alloys show moderate direct bandgap bowing with a bowing parameter, B = 1.41 ± 0.19 eV. The direct bandgap of metastable rocksalt AlN is extrapolated to be 4.70 ± 0.20 eV. The tunable lattice parameter, bandgap, dielectric permittivity, and electronic properties of rocksalt Al<sub>xSc>1-xsub>N alloys enable high quality epitaxial rocksalt metal/Al<sub>xSc>1-xsub>N superlattices with a wide range of accessible metamaterials properties.

  15. Facile synthesis and characterization of ZnFe{sub 2}O{sub 4}/{alpha}-Fe{sub 2}O{sub 3} composite hollow nanospheres

    SciTech Connect (OSTI)

    Shen, Yu [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China) [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); School of Environmental and Chemical Engineering, Dalian Jiaotong University, Dalian 116028 (China); Li, Xinyong, E-mail: xyli@dlut.edu.cn [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China) [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); Department of Chemical Engineering, Curtin University, Perth, WA 6845 (Australia); Zhao, Qidong; Hou, Yang [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China)] [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); Tade, Moses [Department of Chemical Engineering, Curtin University, Perth, WA 6845 (Australia)] [Department of Chemical Engineering, Curtin University, Perth, WA 6845 (Australia); Liu, Shaomin, E-mail: Shaomin.Liu@curtin.edu.au [Department of Chemical Engineering, Curtin University, Perth, WA 6845 (Australia)] [Department of Chemical Engineering, Curtin University, Perth, WA 6845 (Australia)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer ZnFe{sub 2}O{sub 4}/{alpha}-Fe{sub 2}O{sub 3} composite hollow nanospheres were successfully synthesized via a facile method. Black-Right-Pointing-Pointer Detailed structural, morphology and the phase composition were studied. Black-Right-Pointing-Pointer The incorporation of ZnFe{sub 2}O{sub 4} and {alpha}-Fe{sub 2}O{sub 3} gives an appropriate band gap value to utilize solar energy. -- Abstract: ZnFe{sub 2}O{sub 4}/{alpha}-Fe{sub 2}O{sub 3} composite hollow nanospheres were successfully fabricated via a facile one-pot solvothermal method, utilizing polyethylene glycol as soft template. X-ray diffraction and scanning electron microscopy analysis revealed that the prepared nanospheres with cubic spinel and rhombohedra composite structure had a uniform diameter of about 370 nm, and the hollow structure could be further confirmed by transmission electron microscopy. Energy dispersive X-ray, X-ray photoelectron spectroscopy and Fourier transform infrared techniques were also applied to characterize the elemental composition and chemical bonds in the hollow nanospheres. The ZnFe{sub 2}O{sub 4}/{alpha}-Fe{sub 2}O{sub 3} composite hollow nanospheres show attractive light absorption property for potential applications in electronics, optics, and catalysis.

  16. Redox probing study of the potential dependence of charge transport through Li<sub>2sub>O>2sub>

    SciTech Connect (OSTI)

    Knudsen, Kristian B.; Luntz, Alan C.; Jensen, Søren H.; Vegge, Tejs; Hjelm, Johan

    2015-11-20

    In the field of energy storage devices the pursuit for cheap, high energy density, reliable secondary batteries is at the top of the agenda. The Li–O<sub>2sub> battery is one of the possible technologies that, in theory, should be able to close the gap, which exists between the present state-of-the-art Li-ion technologies and the demand placed on batteries by technologies such as electrical vehicles. Here we present a redox probing study of the charge transfer across the main deposition product lithium peroxide, Li<sub>2sub>O>2sub>, in the Li–O<sub>2sub> battery using outer-sphere redox shuttles. The change in heterogeneous electron transfer exchange rate as a function of the potential and the Li<sub>2sub>O>2sub> layer thickness (~depth-of-discharge) was determined using electrochemical impedance spectroscopy. In addition, the attenuation of the electron transfer exchange rate with film thickness is dependent on the probing potential, providing evidence that hole transport is the dominant process for charge transfer through Li<sub>2sub>O>2sub> and showing that the origin of the sudden death observed upon discharge is due to charge transport limitations.

  17. Thermal conductivity of bulk and nanowire Mg?Si<sub>xSn>1xsub> alloys from first principles

    SciTech Connect (OSTI)

    Li, Wu; Lindsay, L.; Broido, D. A.; Stewart, Derek A.; Mingo, Natalio

    2012-11-29

    The lattice thermal conductivity (?) of the thermoelectric materials, Mg?Si, Mg?Sn, and their alloys, are calculated for bulk and nanowires, without adjustable parameters. We find good agreement with bulk experimental results. For large nanowire diameters, size effects are stronger for the alloy than for the pure compounds. For example, in 200 nm diameter nanowires ? is lower than its bulk value by 30%, 20%, and 20% for Mg?Si?.?Sn?.?, Mg?Si, and Mg?Sn, respectively. For nanowires less than 20 nm thick, the relative decrease surpasses 50%, and it becomes larger in the pure compounds than in the alloy. At room temperature, ? of Mg?Si<sub>xSn>1xsub> is less sensitive to nanostructuring size effects than Si<sub>xGe>1xsub>, but more sensitive than PbTe<sub>xSe>1xsub>. This suggests that further improvement of Mg?Si<sub>xSn>1xsub> as a nontoxic thermoelectric may be possible.

  18. Development of epitaxial Al<sub>xSc>1-xsub>N for artificially structured metal/semiconductor superlattice metamaterials

    SciTech Connect (OSTI)

    Sands, Timothy D.; Stach, Eric A.; Saha, Bivas; Saber, Sammy; Naik, Gururaj V.; Boltasseva, Alexandra; Kvam, Eric P.

    2015-02-01

    Epitaxial nitride rocksalt metal/semiconductor superlattices are emerging as a novel class of artificially structured materials that have generated significant interest in recent years for their potential application in plasmonic and thermoelectric devices. Though most nitride metals are rocksalt, nitride semiconductors in general have hexagonal crystal structure. We report rocksalt aluminum scandium nitride (Al,Sc)N alloys as the semiconducting component in epitaxial rocksalt metal/semiconductor superlattices. The Al<sub>xSc>1-xsub>N alloys when deposited directly on MgO substrates are stabilized in a homogeneous rocksalt (single) phase when x < 0.51. Employing 20 nm TiN as a seed layer on MgO substrates, the homogeneity range for stabilizing the rocksalt phase has been extended to x < 0.82 for a 120 nm film. The rocksalt Al<sub>xSc>1-xsub>N alloys show moderate direct bandgap bowing with a bowing parameter, B = 1.41 0.19 eV. The direct bandgap of metastable rocksalt AlN is extrapolated to be 4.70 0.20 eV. The tunable lattice parameter, bandgap, dielectric permittivity, and electronic properties of rocksalt Al<sub>xSc>1-xsub>N alloys enable high quality epitaxial rocksalt metal/Al<sub>xSc>1-xsub>N superlattices with a wide range of accessible metamaterials properties.

  19. Single-vortex pinning and penetration depth in superconducting NdFeAsO<sub>1-xsub>Fx>

    SciTech Connect (OSTI)

    Zhang, Jessie T.; Kim, Jeehoon; Huefner, Magdalena; Ye, Cun; Kim, Stella; Canfield, Paul C.; Prozorov, Ruslan; Auslaender, Ophir M.; Hoffman, Jennifer E.

    2015-10-12

    We use a magnetic force microscope (MFM) to investigate single vortex pinning and penetration depth in NdFeAsO<sub>1-xsub>Fx>, one of the highest-T<sub>c> iron-based superconductors. In fields up to 20 Gauss, we observe a disordered vortex arrangement, implying that the pinning forces are stronger than the vortex-vortex interactions. We measure the typical force to depin a single vortex, F<sub>depin> ≃ 4.5 pN, corresponding to a critical current up to J<sub>c> ≃ 7×105 A/cm2. As a result, our MFM measurements allow the first local and absolute determination of the superconducting in-plane penetration depth in NdFeAsO<sub>1-xsub>Fx>, λ<sub>ab> = 320 ± 60 nm, which is larger than previous bulk measurements.

  20. Design of Semiconducting Tetrahedral Mn1<sub>-xZnx>O Alloys and Their Application to Solar Water Splitting

    SciTech Connect (OSTI)

    Peng, Haowei; Ndione, Paul F.; Ginley, David S.; Zakutayev, A.; Lany, Stephen

    2015-05-18

    Both structure-property and composition-structure relationships are exploited to design and realize novel wurtzite-structure Mn1<sub>-xZnx>O alloys. A proof of principle is provided that corroborates, in particular, the predicted favorable hole-transport properties of these alloys.

  1. Combined effects of post-growth thermal treatment and chemical substitution on physical properties of CaFe<sub>2sub>As>2sub>

    SciTech Connect (OSTI)

    Ran, Sheng

    2014-12-01

    This thesis summarizes experimental work using process of postgrowth thermal treatment and chemical substitution as tuning parameters in the study of physical properties of CaFe<sub>2sub>As>2sub>. Details of sample preparation and characterization are given as well as various phase diagrams.

  2. Sintered Cr/Pt and Ni/Au ohmic contacts to B<sub>12sub>P>2sub>

    SciTech Connect (OSTI)

    Frye, Clint D.; Kucheyev, Sergei O.; Edgar, James H.; Voss, Lars F.; Conway, Adam M.; Shao, Qinghui; Nikolic, Rebecca J.

    2015-04-09

    With this study, icosahedral boron phosphide (B<sub>12sub>P>2sub>) is a wide-bandgap semiconductor possessing interesting properties such as high hardness, chemical inertness, and the reported ability to self-heal from irradiation by high energy electrons. Here, the authors developed Cr/Pt and Ni/Au ohmic contacts to epitaxially grown B<sub>12sub>P>2sub> for materials characterization and electronic device development. Cr/Pt contacts became ohmic after annealing at 700 °C for 30 s with a specific contact resistance of 2×10–4 Ω cm2, as measured by the linear transfer length method. Ni/Au contacts were ohmic prior to any annealing, and their minimum specific contact resistance was ~l–4 × 10–4 Ω cm2 after annealing over the temperature range of 500–800 °C. Rutherford backscattering spectrometry revealed a strong reaction and intermixing between Cr/Pt and B<sub>12sub>P>2sub> at 700 °C and a reaction layer between Ni and B<sub>12sub>P>2sub> thinner than ~25 nm at 500 °C.

  3. Surface reactions of ethanol over UO<sub>2sub>(100) thin film

    SciTech Connect (OSTI)

    S. D. Senanayake; Mudiyanselage, K.; Burrell, A. K.; Sadowski, J. T.; Idriss, H.

    2015-10-08

    The study of the reactions of oxygenates on well-defined oxide surfaces is important for the fundamental understanding of heterogeneous chemical pathways that are influenced by atomic geometry, electronic structure, and chemical composition. In this work, an ordered uranium oxide thin film surface terminated in the (100) orientation is prepared on a LaAlO<sub>3sub> substrate and studied for its reactivity with a C-2 oxygenate, ethanol (CH<sub>3sub>CH>2sub>OH). With the use of synchrotron X-ray photoelectron spectroscopy (XPS), we have probed the adsorption and desorption processes observed in the valence band, C 1s, O 1s, and U 4f to investigate the bonding mode, surface composition, electronic structure, and probable chemical changes to the stoichiometric-UO<sub>2sub>(100) [smooth-UO<sub>2sub>(100)] and Ar+-sputtered UO<sub>2sub>(100) [rough-UO<sub>2sub>(100)] surfaces. Unlike UO<sub>2sub>(111) single crystal and UO<sub>2sub> thin film, Ar-ion-sputtering of this UO<sub>2sub>(100) did not result in noticeable reduction of U cations. Upon ethanol adsorption (saturation occurred at 0.5 ML), only the ethoxy (CH<sub>3sub>CH>2sub>O) species is formed on smooth-UO<sub>2sub>(100) whereas initially formed ethoxy species are partially oxidized to surface acetate (CH3COO–) on the Ar+-sputtered UO<sub>2sub>(100) surface. Furthermore, all ethoxy and acetate species are removed from the surface between 600 and 700 K.

  4. New simple A{sub 4} neutrino model for nonzero {theta}{sub 13} and large {delta}{sub CP}

    SciTech Connect (OSTI)

    Ishimori, Hajime

    2013-05-23

    In a new simple application of the non-Abelian discrete symmetry A{sub 4} to charged-lepton and neutrino mass matrices, we show that for the current experimental central value of sin{sup 2} 2{theta}{sub 13} Asymptotically-Equal-To 0.1, leptonic CP violation is necessarily large, i.e. Double-Vertical-Line tan{delta}{sub CP} Double-Vertical-Line > 1.3. We also consider T{sub 7} model with one parameter to be complex, thus allowing for one Dirac CP phase {delta}{sub CP} and two Majorana CP phases {alpha}{sub 1,2}. We find a slight modification to this correlation as a function of {delta}{sub CP}. For a given set of input values of {Delta}m{sup 2}{sub 21}, {Delta}m{sup 2}{sub 32}, {theta}{sub 12}, and {theta}{sub 13}, we obtain sin{sup 2} 2{theta}{sub 23} and m{sub ee} (the effective Majorana neutrino mass in neutrinoless double beta decay) as functions of tan {delta}{sub CP}. We find that the structure of this model always yields small Double-Vertical-Line tan {delta}{sub CP} Double-Vertical-Line .

  5. Microstructures and properties of CH{sub 3}NH{sub 3}PbI{sub 3?x}Cl{sub x} hybrid solar cells

    SciTech Connect (OSTI)

    Suzuki, Kohei E-mail: oku@mat.usp.ac.jp; Suzuki, Atsushi E-mail: oku@mat.usp.ac.jp; Zushi, Masahito E-mail: oku@mat.usp.ac.jp; Oku, Takeo E-mail: oku@mat.usp.ac.jp

    2015-02-27

    Halide-perovskite CH{sub 3}NH{sub 3}PbI{sub 3} was produced on mesoporous TiO{sub 2} layer by spin-coating a precursor solution of PbCl{sub 2} and CH{sub 3}NH{sub 3}I in dimethylformamide. The role of the annealing process and chlorine (Cl) doping for the perovskite-phase formation was investigated. It was found that crystallization of the perovskite materials was stimulated by the annealing process, and that longer annealing time is necessary for the Cl-doped perovskite compared with that of non-doped perovskite phase.

  6. Hysteretic electrical transport in BaTiO{sub 3}/Ba{sub 1?x}Sr{sub x}TiO{sub 3}/Ge heterostructures

    SciTech Connect (OSTI)

    Ngai, J. H.; Kumah, D. P.; Walker, F. J.; Ahn, C. H.

    2014-02-10

    We present electrical transport measurements of heterostructures comprised of BaTiO{sub 3} and Ba{sub 1?x}Sr{sub x}TiO{sub 3} epitaxially grown on Ge. Sr alloying imparts compressive strain to the BaTiO{sub 3}, which enables the thermal expansion mismatch between BaTiO{sub 3} and Ge to be overcome to achieve c-axis oriented growth. The conduction bands of BaTiO{sub 3} and Ba{sub 1?x}Sr{sub x}TiO{sub 3} are nearly aligned with the conduction band of Ge, which facilitates electron transport. Electrical transport measurements through the dielectric stack exhibit rectifying behavior and hysteresis, where the latter is consistent with ferroelectric switching.

  7. Communication: Imaging the effects of the antisymmetric-stretching excitation in the O({sup 3}P) + CH{sub 4}(v{sub 3} = 1) reaction

    SciTech Connect (OSTI)

    Pan, Huilin [Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P. O. Box 23-166, Taipei 10617, Taiwan (China) [Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P. O. Box 23-166, Taipei 10617, Taiwan (China); State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Liu, Kopin, E-mail: kliu@po.iams.sinica.edu.tw [Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P. O. Box 23-166, Taipei 10617, Taiwan (China)] [Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P. O. Box 23-166, Taipei 10617, Taiwan (China)

    2014-05-21

    Effects of one-quantum excitation of the antisymmetric-stretching mode of CH{sub 4}(v{sub 3} = 1) on the O({sup 3}P) + CH{sub 4} reaction were studied in a crossed-beam, ion-imaging experiment. In the post-threshold region, we found that (1) the product state distributions are dominated by the CH{sub 3}(0{sub 0}) + OH(v{sup ?} = 1) pair, (2) the product angular distributions extend toward sideways from the backward dominance of the ground-state reaction, and (3) vibrational excitation exerts a positive effect on reactivity, but translational energy is more efficient in promoting the rate of this central-barrier reaction. All major findings agree reasonably well with recent theoretical results. Some remaining questions are pointed out.

  8. INVESTIGATING THE MINIMUM ENERGY PRINCIPLE IN SEARCHES FOR NEW MOLECULAR SPECIESTHE CASE OF H{sub 2}C{sub 3}O ISOMERS

    SciTech Connect (OSTI)

    Loomis, Ryan A.; McGuire, Brett A.; Remijan, Anthony J.; Shingledecker, Christopher; Johnson, Chelen H.; Blair, Samantha; Robertson, Amy

    2015-01-20

    Recently, Lattelais et al. have interpreted aggregated observations of molecular isomers to suggest that there exists a ''minimum energy principle'', such that molecular formation will favor more stable molecular isomers for thermodynamic reasons. To test the predictive power of this principle, we have fully characterized the spectra of the three isomers of C{sub 3}H{sub 2}O toward the well-known molecular region SgrB2(N). Evidence for the detection of the isomers cyclopropenone (c-C{sub 3}H{sub 2}O) and propynal (HCCCHO) is presented, along with evidence for the non-detection of the lowest zero-point energy isomer, propadienone (CH{sub 2}CCO). We interpret these observations as evidence that chemical formation pathways, which may be under kinetic control, have a more pronounced effect on final isomer abundances than thermodynamic effects such as the minimum energy principle.

  9. Resolution of the discrepancy between the variation of the physical properties of Ce<sub>1-xsub>YbxCoIn>5sub> single crystals and thin films with Yb composition

    SciTech Connect (OSTI)

    Jang, S.; White, B. D.; Lum, I. K.; Kim, H.; Tanatar, M. A.; Straszheim, W. E.; Prozorov, R.; Keiber, T.; Bridges, F.; Shu, L.; Baumbach, R. E.; Janoschek, M.; Maple, M. B.

    2014-11-18

    The extraordinary electronic phenomena including an Yb valence transition, a change in Fermi surface topology, and suppression of the heavy fermion quantum critical field at a nominal concentration x≈0.2 have been found in the Ce<sub>1-xsub>YbxCoIn>5sub> system. These phenomena have no discernable effect on the unconventional superconductivity and normal-state non-Fermi liquid behaviour that occur over a broad range of x up to ~0.8. However, the variation of the coherence temperature T* and the superconducting critical temperature T<sub>c> with nominal Yb concentration x for bulk single crystals is much weaker than that of thin films. To determine whether differences in the actual Yb concentration of bulk single crystals and thin film samples might be responsible for these discrepancies, we employed Vegard’s law and the spectroscopically determined values of the valences of Ce and Yb as a function of x to determine the actual composition x<sub>act> of bulk single crystals. This analysis is supported by energy-dispersive X-ray spectroscopy, wavelength-dispersive X-ray spectroscopy, and transmission X-ray absorption edge spectroscopy measurements. The actual composition x<sub>act> is found to be about one-third of the nominal concentration x up to x~0.5, and resolves the discrepancy between the variation of the physical properties of Ce<sub>1-xsub>YbxCoIn>5sub> single crystals and thin films with Yb concentration.

  10. Yb{sub 5}Ni{sub 4}Sn{sub 10} and Yb{sub 7}Ni{sub 4}Sn{sub 13}: New polar intermetallics with 3D framework structures

    SciTech Connect (OSTI)

    Lei Xiaowu; Sun Zhongming; Li Longhua; Zhong Guohua; Hu Chunli; Mao Jianggao

    2010-04-15

    The title compounds have been obtained by solid state reactions of the corresponding pure elements at high temperature, and structurally characterized by single-crystal X-ray diffraction studies. Yb{sub 5}Ni{sub 4}Sn{sub 10} adopts the Sc{sub 5}Co{sub 4}Si{sub 10} structure type and crystallizes in the tetragonal space group P4/mbm (No. 127) with cell parameters of a=13.785(4) A, c=4.492 (2) A, V=853.7(5) A{sup 3}, and Z=2. Yb{sub 7}Ni{sub 4}Sn{sub 13} is isostructural with Yb{sub 7}Co{sub 4}InGe{sub 12} and crystallizes in the tetragonal space group P4/m (No. 83) with cell parameters of a=11.1429(6) A, c=4.5318(4) A, V=562.69(7) A{sup 3}, and Z=1. Both structures feature three-dimensional (3D) frameworks based on three different types of one-dimensional (1D) channels, which are occupied by the Yb atoms. Electronic structure calculations based on density functional theory (DFT) indicate that both compounds are metallic. These results are in agreement with those from temperature-dependent resistivity and magnetic susceptibility measurements. - Graphical abstract: Two new ytterbium nickel stannides, namely, Yb{sub 5}Ni{sub 4}Sn{sub 10} and Yb{sub 7}Ni{sub 4}Sn{sub 13}, have been synthesized and structurally characterized by single-crystal X-ray diffraction studies. Both their structures feature three-dimensional (3D) frameworks based on three different types of one-dimensional (1D) channels, which are situated by all the Yb atoms. Electronic structure calculations based on density functional theory (DFT) indicate that both compounds are metallic, which are in accordance with the results from temperature-dependent resistivity and magnetic susceptibility measurements.

  11. Synthesis, structure and chemical bonding of CaFe{sub 2?x}Rh{sub x}Si{sub 2} (x=0, 1.32, and 2) and SrCo{sub 2}Si{sub 2}

    SciTech Connect (OSTI)

    Hlukhyy, Viktor Hoffmann, Andrea V.; Fssler, Thomas F.

    2013-07-15

    The finding of superconductivity in Ba{sub 0.6}K{sub 0.4}Fe{sub 2}As{sub 2} put the attention on the investigation of compounds that crystallize with ThCr{sub 2}Si{sub 2} structure type such as AT{sub 2}X{sub 2} (A=alkali/alkaline earth/rare earth element; T=transition metal and X=element of the 1315th group). In this context the silicides CaFe{sub 2}Si{sub 2}, CaFe{sub 0.68(6)}Rh{sub 1.32(6)}Si{sub 2}, CaRh{sub 2}Si{sub 2} and SrCo{sub 2}Si{sub 2} have been synthesized by reaction of the elements under an argon atmosphere. Single crystals were obtained by special heat treatment in welded niobium/tantalum ampoules. The compounds were investigated by means of powder and single crystal X-ray diffraction. All compounds crystallize in the ThCr{sub 2}Si{sub 2}-type structure with space group I4/mmm (No. 139): a=3.939(1) , c=10.185(1) , R{sub 1}=0.045, 85 F{sup 2} values, 8 variable parameters for CaFe{sub 2}Si{sub 2}; a=4.0590(2) , c=9.9390(8) , R{sub 1}=0.030, 90 F{sup 2} values, 10 variable parameters for CaFe{sub 0.68(6)}Rh{sub 1.32(6)}Si{sub 2}; a=4.0695(1) , c=9.9841(3) , R{sub 1}=0.031, 114 F{sup 2} values, 9 variable parameters for CaRh{sub 2}Si{sub 2}; and a=3.974(1) , c=10.395(1) , R{sub 1}=0.036, 95 F{sup 2} values, 8 variable parameters for SrCo{sub 2}Si{sub 2}. The structure of SrCo{sub 2}Si{sub 2} contains isolated [Co{sub 2}Si{sub 2}]{sup 2?} 2D-layers in the ab-plane whereas in CaFe{sub 2?x}Rh{sub x}Si{sub 2} the [T{sub 2}Si{sub 2}] layers (T=Fe and Rh) are interconnected along the c-axis via Si3Si bonds resulting in a three-dimentional (3D) [T{sub 2}Si{sub 2}]{sup 2?} polyanions and therefore belong to the so-called collapsed form of the ThCr{sub 2}Si{sub 2}-type structure. The SrCo{sub 2}Si{sub 2} and CaRh{sub 2}Si{sub 2} are isoelectronic to the parent 122 ironpnictide superconductors AeFe{sub 2}As{sub 2} (Ae=alkaline earth elements), whereas CaFe{sub 2}Si{sub 2} is a full substituted variant (As/Si) of CaFe{sub 2}As{sub 2}. The crystal chemistry and chemical bonding in the title compounds are discussed in terms of LMTO band structure calculations and a topological analysis using the Electron Localization Function (ELF). - Graphical abstract: The SrCo{sub 2}Si{sub 2} and CaFe{sub 2?x}Rh{sub x}Si{sub 2} (x==0, 1.32, and 2) crystallize in the ThCr{sub 2}Si{sub 2}-type. The structure of SrCo{sub 2}Si{sub 2} contains isolated [Co{sub 2}Si{sub 2}]{sup 2?} layers in the ab-plane, whereas the [T{sub 2}Si{sub 2}] layers in CaFe{sub 2?x}Rh{sub x}Si{sub 2} are interconnected along the c-axis via Si3Si bonds resulting in a [T{sub 2}Si{sub 2}]{sup 2?} network. - Highlights: Synthesis and structure of ternary silicides SrCo{sub 2}Si{sub 2} and CaFe{sub 2?x}Rh{sub x}Si{sub 2} (x=0, 1.32, and 2). The SrCo{sub 2}Si{sub 2} and CaRh{sub 2}Si{sub 2} are isoelectronic to the parent 122 ironpnictide superconductors AeFe{sub 2}As{sub 2}. CaFe{sub 2}Si{sub 2} is a full substituted variant (As/Si) of superconductor CaFe{sub 2}As{sub 2}. The title compounds demonstrate the tunable Si3Si distances.

  12. Heavy fermion Ce{sub 3}Co{sub 4}Sn{sub 13} compound under pressure

    SciTech Connect (OSTI)

    Collave, J. R.; Borges, H. A.; Ramos, S. M.; Hering, E. N.; Mendona-Ferreira, L.; Pagliuso, P. G.

    2015-05-07

    The non-magnetic heavy fermion compound Ce{sub 3}Co{sub 4}Sn{sub 13} was studied under pressure. We report single crystalline measurements of electrical resistivity as a function of temperature ?(T) under pressure. Some characteristic features related to a structural transition (T{sub S}), crystalline field effects (T{sub CEF}), and a low temperature maximum (T{sub max}), possibly connected simultaneously to the onset of Kondo lattice coherence and short range magnetic correlations, were identified in the ?(T) data. A pressure-temperature phase diagram with T{sub S} and T{sub max} was constructed by mapping these features. Like for most Ce-based heavy fermion compounds, T{sub max} moves to higher temperatures with pressure, indicating that it is related to the Kondo energy scale, due to the increase of hybridization induced by pressure. On the other hand, T{sub S}, associated to a superlattice distortion and probably combined with a charge density wave transition, decreases as a function of pressure. However, differently from the Sr{sub 3?x}Ca{sub x}Ir{sub 4}Sn{sub 13} system, where a superlattice quantum phase transition is observed [L. E. Klintberg et al., Phys. Rev. Lett. 109, 237?008 (2012)], in Ce{sub 3}Co{sub 4}Sn{sub 13} T{sub S}???154?K, at ambient pressure (P?=?0), seems to stabilize at around 143?K for P???19 kilobars. We also investigated ?(T) in external magnetic fields, at P?=?0. Negative magnetoresistance and increase of T{sub max} are observed, suggesting suppression of low temperature short range magnetic correlations.

  13. Dynamics of the reaction of C{sub 3}(a{sup 3}Π{sub u}) radicals with C{sub 2}H{sub 2}: A new source for the formation of C{sub 5}H

    SciTech Connect (OSTI)

    Huang, Wen-Jian; Sun, Yi-Lun; Chin, Chih-Hao; Lee, Shih-Huang

    2014-09-28

    The reaction C{sub 3}(a{sup 3}Π{sub u}) + C{sub 2}H{sub 2} → C{sub 5}H + H was investigated at collision energy 10.9 kcal mol{sup −1} that is less than the enthalpy of ground-state reaction C{sub 3}(X{sup 1}Σ{sub g}{sup +}) + C{sub 2}H{sub 2} → C{sub 5}H + H. C{sub 3}(a{sup 3}Π{sub u}) radicals were synthesized from 1% C{sub 4}F{sub 6}/He by pulsed high-voltage discharge. The title reaction was conducted in a crossed molecular-beam apparatus equipped with a quadrupole-mass filter. Product C{sub 5}H was interrogated with time-of-flight spectroscopy and synchrotron vacuum-ultraviolet ionization. Reactant C{sub 3}(a{sup 3}Π{sub u}) and product C{sub 5}H were identified using photoionization spectroscopy. The ionization thresholds of C{sub 3}(X{sup 1}Σ{sub g}{sup +}) and C{sub 3}(a{sup 3}Π{sub u}) are determined as 11.6 ± 0.2 eV and 10.0 ± 0.2 eV, respectively. The C{sub 5}H product is identified as linear pentynylidyne that has an ionization energy 8.4 ± 0.2 eV. The title reaction releases translational energy 10.6 kcal mol{sup −1} in average and has an isotropic product angular distribution. The quantum-chemical calculation indicates that the C{sub 3}(a{sup 3}Π{sub u}) radical attacks one of the carbon atoms of C{sub 2}H{sub 2} and subsequently a hydrogen atom is ejected to form C{sub 5}H + H, in good agreement with the experimental observation. As far as we are aware, the C{sub 3}(a{sup 3}Π{sub u}) + C{sub 2}H{sub 2} reaction is investigated for the first time. This work gives an implication for the formation of C{sub 5}H from the C{sub 3}(a{sup 3}Π{sub u}) + C{sub 2}H{sub 2} reaction occurring in a combustion or discharge process of C{sub 2}H{sub 2}.

  14. Adventures on the C<sub>3sub>H>5sub>O potential energy surface: OH+propyne, OH+allene and related reactions

    SciTech Connect (OSTI)

    Zádor, Judit; Miller, James A.

    2014-06-25

    We mapped out the stationary points and the corresponding conformational space on the C<sub>3sub>H>5sub>O potential energy surface relevant for the OH + allene and OH + propyne reactions systematically and automatically using the KinBot software at the UCCSD(T)-F12b/cc-pVQZ-F12//M06-2X/6-311++G(d,p) level of theory. We used RRKM-based 1-D master equations to calculate pressure- and temperature-dependent, channel-specific phenomenological rate coefficients for the bimolecular reactions propyne + OH and allene + OH, and for the unimolecular decomposition of the CH<sub>3sub>CCHOH, CH<sub>3sub>C(OH)CH, CH<sub>2sub>CCH>2sub>OH, CH<sub>2sub>C(OH)CH>2sub> primary adducts, and also for the related acetonyl, propionyl, 2-methylvinoxy, and 3-oxo-1-propyl radicals. The major channel of the bimolecular reactions at high temperatures is the formation propargyl + H<sub>2sub>O, which makes the title reactions important players in soot formation at high temperatures. However, below ~1000 K the chemistry is more complex, involving the competition of stabilization, isomerization and dissociation processes. We found that the OH addition to the central carbon of allene has a particularly interesting and complex pressure dependence, caused by the low-lying exit channel to form ketene + CH<sub>3sub> bimolecular products. In this study, we compared our results to a wide range of experimental data and assessed possible uncertainties arising from certain aspects of the theoretical framework.

  15. Highly Flexible Self-Assembled V<sub>2sub>O>5sub> Cathodes Enabled by Conducting Diblock Copolymers

    SciTech Connect (OSTI)

    An, Hyosung; Mike, Jared; Smith, Kendall A.; Swank, Lisa; Lin, Yen-Hao; L. Pesek, Stacy; Verduzco, Rafael; Lutkenhaus, Jodie L.

    2015-09-22

    Mechanically robust battery electrodes are desired for applications in wearable devices, flexible displays, and structural energy and power. In this regard, the challenge is to balance mechanical and electrochemical properties in materials that are inherently brittle. Here, we demonstrate a unique water-based self-assembly approach that incorporates a diblock copolymer bearing electron- and ion-conducting blocks, poly(3-hexylthiophene)-block-poly(ethyleneoxide) (P3HT-b-PEO), with V<sub>2sub>O>5sub> to form a flexible, tough, carbon-free hybrid battery cathode. V<sub>2sub>O>5sub> is a promising lithium intercalation material, but it remains limited by its poor conductivity and