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  1. NVN-89275 | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Type NOI Decision Document Date 20101202 Relevant Numbers Lead Agency Doc Number Serial Number NVN-89275 Proposed Action Geophysical surveys. Documents Serial Register Page:...

  2. NVN-89274 | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Type NOI Decision Document Date 20101202 Relevant Numbers Lead Agency Doc Number Serial Number NVN-89274 Lease Numbers NVN-085716 NVN-086893 NVN-088920 Proposed Action...

  3. Augusta Mountains Geothermal Area | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Date Decision Date Lead Agency Development Phase(s) Techniques NVN-89274 CU AltaRock Energy Inc 4 November 2010 2 December 2010 BLM GeothermalExploration Geophysical...

  4. Property:NEPA PreApplicationMeetingDate | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    2010 + NVN-89274 + 26 October 2010 + S San Juan Basin EC + 5 November 2008 + Sigurd Red Butte No2 + 19 December 2008 + Southline Transmission Line + 4 April 2012 + Sun Valley...

  5. Cu

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Cu rre n t Ge n e ratio n Lo w En e rg y Cro s s Se c tio n Me as u re m e n ts : Sc iBar an d Min iBo o NE MiniBooNE Beam ➢ 8 GeV protons on Be target ➢ <E ν > = 0.7 GeV ➢ Change horn polarity for ν, ν modes Detector ➢ 12 m diameter, 800 ton mineral oil (CH 2 ) tank ➢ 1280 inner PMTs, 240 veto PMTs ➢ Events produce prompt Cherenkov light and delayed, isotropic scintillation light ➢ A " subevent" is cluster of tank activity in time ν µ µ - e - e + π + µ + K2

  6. Thermochemical process for recovering Cu from CuO or CuO.sub.2

    DOEpatents

    Richardson, deceased, Donald M.; Bamberger, Carlos E.

    1981-01-01

    A process for producing hydrogen comprises the step of reacting metallic Cu with Ba(OH).sub.2 in the presence of steam to produce hydrogen and BaCu.sub.2 O.sub.2. The BaCu.sub.2 O.sub.2 is reacted with H.sub.2 O to form Cu.sub.2 O and a Ba(OH).sub.2 product for recycle to the initial reaction step. Cu can be obtained from the Cu.sub.2 O product by several methods. In one embodiment the Cu.sub.2 O is reacted with HF solution to provide CuF.sub.2 and Cu. The CuF.sub.2 is reacted with H.sub.2 O to provide CuO and HF. CuO is decomposed to Cu.sub.2 O and O.sub.2. The HF, Cu and Cu.sub.2 O are recycled. In another embodiment the Cu.sub.2 O is reacted with aqueous H.sub.2 SO.sub.4 solution to provide CuSO.sub.4 solution and Cu. The CuSO.sub.4 is decomposed to CuO and SO.sub.3. The CuO is decomposed to form Cu.sub.2 O and O.sub.2. The SO.sub.3 is dissolved to form H.sub.2 SO.sub.4. H.sub.2 SO.sub.4, Cu and Cu.sub.2 O are recycled. In another embodiment Cu.sub.2 O is decomposed electrolytically to Cu and O.sub.2. In another aspect of the invention, Cu is recovered from CuO by the steps of decomposing CuO to Cu.sub.2 O and O.sub.2, reacting the Cu.sub.2 O with aqueous HF solution to produce Cu and CuF.sub.2, reacting the CuF.sub.2 with H.sub.2 O to form CuO and HF, and recycling the CuO and HF to previous reaction steps.

  7. Hydrodynamic evolution and jet energy loss in Cu + Cu collisions

    SciTech Connect

    Schenke, Bjoern; Jeon, Sangyong; Gale, Charles

    2011-04-15

    We present results from a hybrid description of Cu + Cu collisions using (3 + 1)-dimensional hydrodynamics (music) for the bulk evolution and a Monte Carlo simulation (martini) for the evolution of high-momentum partons in the hydrodynamical background. We explore the limits of this description by going to small system sizes and determine the dependence on different fractions of wounded nucleon and binary collisions scaling of the initial energy density. We find that Cu + Cu collisions are well described by the hybrid description at least up to 20% central collisions.

  8. Cu 2 S 3 complex on Cu(111) as a candidate for mass transport...

    Office of Scientific and Technical Information (OSTI)

    Cu 2 S 3 complex on Cu(111) as a candidate for mass transport enhancement Citation Details In-Document Search Title: Cu 2 S 3 complex on Cu(111) as a candidate for mass transport ...

  9. cu | OpenEI Community

    OpenEI (Open Energy Information) [EERE & EIA]

    ancient building system architect biomimicry building technology cooling cu daylight design problem energy use engineer fred andreas geothermal green building heat transfer...

  10. Science DMZ Implemented at CU Boulder

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    CU Science Engagement Move your data Programs & Workshops Science Requirements Reviews Case Studies OSCARS Case Studies Science DMZ Case Studies Science DMZ @ UF Science DMZ @ CU ...

  11. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    0 New Hampshire - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle ...

  12. Property:NEPA CU Document | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    CU Document Jump to: navigation, search Property Name NEPA CU Document Property Type Page Description CU files for NEPA Docs. Typically Casual Use Documentation consists of a...

  13. Phase transformation between Cu(In,Sn){sub 2} and Cu{sub 2}(In,Sn) compounds formed on single crystalline Cu substrate during solid state aging

    SciTech Connect

    Tian, Feifei; Liu, Zhi-Quan Guo, Jingdong

    2014-01-28

    Interfacial reactions between eutectic SnIn and single crystalline Cu during solid-state aging at low temperature were investigated systematically. Three types of phase transformations between Cu(In,Sn){sub 2} layer and Cu{sub 2}(In,Sn) layer were observed, which are Cu(In,Sn){sub 2} grows and Cu{sub 2}(In,Sn) consumes at 40?C, Cu(In,Sn){sub 2} and Cu{sub 2}(In,Sn) grow simultaneously at 60?C, as well as Cu(In,Sn){sub 2} consumes and Cu{sub 2}(In,Sn) grows at 80 and 100?C. According to physicochemical approach, the chemical reactions at Cu/Cu{sub 2}(In,Sn)/Cu(In,Sn){sub 2}/SnIn interfaces were discussed in detail. It was concluded that the diffusion ability of Cu and In atoms dominated different phase transformations. When diffusion constants k{sub 1In2}?>?8/3k{sub 1Cu2} Cu(In,Sn){sub 2} will grow, and if k{sub 1Cu2}???k{sub 1In2} Cu{sub 2}(In,Sn) will grow. Both Cu(In,Sn){sub 2} and Cu{sub 2}(In,Sn) can grow in the condition of k{sub 1In2} ? k{sub 1Cu2}. The values of k{sub 1Cu2} and k{sub 1In2} at different temperatures on (100)Cu and (111)Cu substrate were also calculated or estimated by analyzing the growth kinetics of the compound layers.

  14. Accelerating Fatigue Testing for Cu Ribbon Interconnects | Department...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Accelerating Fatigue Testing for Cu Ribbon Interconnects Accelerating Fatigue Testing for Cu Ribbon Interconnects Presented at the 2013 Photovoltaic Module Reliability Workshop; ...

  15. Arizona - Natural Gas 2015 Million Cu. Feet Percent...

    Gasoline and Diesel Fuel Update

    4 Arizona - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: ...

  16. Performance and mix measurements of indirect drive Cu doped Be...

    Office of Scientific and Technical Information (OSTI)

    Performance and mix measurements of indirect drive Cu doped Be implosions Citation Details In-Document Search Title: Performance and mix measurements of indirect drive Cu doped Be ...

  17. Origins of optical absorption characteristics of Cu2+ complexes...

    Office of Scientific and Technical Information (OSTI)

    Origins of optical absorption characteristics of Cu2+ complexes in solutions Citation Details In-Document Search Title: Origins of optical absorption characteristics of Cu2+ ...

  18. Understanding the Deactivation Mechanisms of Cu/Zeolite SCR Catalysts...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Deactivation Mechanisms of CuZeolite SCR Catalysts in Diesel Application Understanding the Deactivation Mechanisms of CuZeolite SCR Catalysts in Diesel Application To understand ...

  19. Investigation of Sulfur Deactivation on Cu/Zeolite SCR Catalysts...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Sulfur Deactivation on CuZeolite SCR Catalysts in Diesel Application Investigation of Sulfur Deactivation on CuZeolite SCR Catalysts in Diesel Application Investigation of Sulfur ...

  20. Cu-Cu direct bonding achieved by surface method at room temperature

    SciTech Connect

    Utsumi, Jun [Advanced Technology Research Center, Mitsubishi Heavy Industries, Ltd., 1-8-1 Sachiura, Kanazawa-ku, Yokohama 236-8515 (Japan); Ichiyanagi, Yuko, E-mail: yuko@ynu.ac.jp [Department of Physics, Graduate School of Engineering, Yokohama National University, Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan)

    2014-02-20

    The metal bonding is a key technology in the processes for the microelectromechanical systems (MEMS) devices and the semiconductor devices to improve functionality and higher density integration. Strong adhesion between surfaces at the atomic level is crucial; however, it is difficult to achieve close bonding in such a system. Cu films were deposited on Si substrates by vacuum deposition, and then, two Cu films were bonded directly by means of surface activated bonding (SAB) at room temperature. The two Cu films, with the surface roughness Ra about 1.3nm, were bonded by using SAB at room temperature, however, the bonding strength was very weak in this method. In order to improve the bonding strength between the Cu films, samples were annealed at low temperatures, between 323 and 473 K, in air. As the result, the Cu-Cu bonding strength was 10 times higher than that of the original samples without annealing.

  1. Direct Epoxidation of Propylene over Stabilized Cu+ Surface Sites on Ti Modified Cu2O

    DOE PAGES [OSTI]

    Yang, X.; Kattel, S.; Xiong, K.; Mudiyanselage, K.; Rykov, S.; Senanayake, S. D.; Rodriguez, J. A.; Liu, P.; Stacchiola, D. J.; Chen, J. G.

    2015-07-17

    Direct propylene epoxidation by O2 is a challenging reaction because of the strong tendency for complete combustion. Results from the current study demonstrate the feasibility to tune the epoxidation selectivity by generating highly dispersed and stabilized Cu+ active sites in a TiCuOx mixed oxide. The TiCuOx surface anchors the key surface intermediate, oxametallacycle, leading to higher selectivity for epoxidation of propylene.

  2. Accelerating Fatigue Testing for Cu Ribbon Interconnects (Presentation)

    SciTech Connect

    Bosco, N.; Silverman, T.; Wohlgemuth , J.; Kurtz, S.; Inoue, M.; Sakurai, K.; Shioda, T.; Zenkoh, H.; Miyashita, M.; Tadanori, T.; Suzuki, S.

    2013-05-01

    This presentation describes fatigue experiments and discusses dynamic mechanical loading for Cu ribbon interconnects.

  3. Theoretical study on the CuH + H. -->. Cu + H/sub 2/ reaction pathway

    SciTech Connect

    Ruiz, M.E.; Garcia-Prieto, J.; Poulain, E.; Ozin, G.A.; Poirier, R.A.; Matta, S.M.; Czismadia, I.G.; Gracie, C.; Novaro, O.

    1986-01-16

    Quite recently, experimental results on the CuH + H ..-->.. Cu + H/sub 2/ thermal matrix phase reaction were reported, indicating that it proceeds with no activation barrier, and no evidence exists for an intermediate CuH/sub 2/ species at 10-13 K. Here the authors present a theoretical study of this reaction using variational and perturbational configuration interaction calculations with a relativistic pseudopotential (PSHONDO-CIPSI) set of programs. The results confirm the lack of a barrier and provide an explanation as to why the CuH/sub 2/ species may not be observed. 11 references, 3 figures, 3 tables.

  4. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    4 Delaware - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S8. Summary statistics for natural gas - Delaware, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 0 0 0 0 0 Gas Wells 0 0 0 0 0 Production (million cubic feet) Gross Withdrawals

  5. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    4 Massachusetts - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S23. Summary statistics for natural gas - Massachusetts, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 0 0 0 0 0 Gas Wells 0 0 0 0 0 Production (million cubic feet) Gross

  6. Comparative study of the alloying effect on the initial oxidation of Cu-Au(100) and Cu-Pt(100)

    SciTech Connect

    Luo, Langli; Zhou, Guangwen; Kang, Yihong; Yang, Judith C.; Su, Dong; Stach, Eric A.

    2014-03-24

    Using in situ transmission electron microscopy, we show that the oxidation of the Cu-Au(100) results in the formation of Cu{sub 2}O islands that deeply embed into the Cu-Au substrate while the oxidation of the Cu-Pt(100) leads to the formation of Cu{sub 2}O islands that highly protrude above the Cu-Pt substrate. Their difference is attributed to the different mobilities of Pt and Au in the Cu base alloys for which the sluggish mobility of Pt in Cu results in trapped Pt atoms at the oxide/alloy interface while the faster mobility of Au in Cu leads to enhanced rehomogenization of the alloy composition.

  7. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    0 Alabama - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S1. Summary statistics for natural gas - Alabama, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 346 367 402 436 414 Gas Wells R 6,243 R 6,203 R 6,174 R 6,117 6,044 Production

  8. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    2 Alaska - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S2. Summary statistics for natural gas - Alaska, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 2,040 1,981 2,006 2,042 2,096 Gas Wells R 274 R 281 R 300 R 338 329 Production

  9. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    0 Colorado - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S6. Summary statistics for natural gas - Colorado, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 5,963 6,456 6,799 7,771 7,733 Gas Wells R 43,792 R 46,141 R 46,883 R 46,876

  10. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    6 District of Columbia - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S9. Summary statistics for natural gas - District of Columbia, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 0 0 0 0 0 Gas Wells 0 0 0 0 0 Production (million cubic

  11. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    4 Hawaii - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S13. Summary statistics for natural gas - Hawaii, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 0 0 0 0 0 Gas Wells 0 0 0 0 0 Production (million cubic feet) Gross Withdrawals From

  12. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    6 Idaho - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S14. Summary statistics for natural gas - Idaho, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 0 0 0 0 0 Gas Wells 0 0 0 0 0 Production (million cubic feet) Gross Withdrawals From

  13. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    20 Maine - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S21. Summary statistics for natural gas - Maine, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 0 0 0 0 0 Gas Wells 0 0 0 0 0 Production (million cubic feet) Gross Withdrawals From

  14. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    0 Mississippi - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S26. Summary statistics for natural gas - Mississippi, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 561 618 581 540 501 Gas Wells R 1,703 R 1,666 R 1,632 R 1,594 1,560

  15. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    4 Montana - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S28. Summary statistics for natural gas - Montana, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 1,956 2,147 2,268 2,377 2,277 Gas Wells R 6,615 R 6,366 R 5,870 R 5,682 5,655

  16. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    4 New Mexico - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S33. Summary statistics for natural gas - New Mexico, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 12,887 13,791 14,171 14,814 14,580 Gas Wells R 40,231 R 40,441 R 40,119 R

  17. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    6 New York - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S34. Summary statistics for natural gas - New York, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 988 1,170 1,589 1,731 1,697 Gas Wells R 7,372 R 7,731 R 7,553 R 7,619 7,605

  18. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    0 North Dakota - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S36. Summary statistics for natural gas - North Dakota, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 5,561 7,379 9,363 11,532 12,799 Gas Wells R 526 R 451 R 423 R 398 462

  19. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    2 Ohio - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S37. Summary statistics for natural gas - Ohio, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 6,775 6,745 7,038 7,257 5,941 Gas Wells R 31,966 R 31,647 R 30,804 R 31,060 26,599

  20. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    4 Oklahoma - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S38. Summary statistics for natural gas - Oklahoma, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 6,723 7,360 8,744 7,105 8,368 Gas Wells R 51,712 R 51,472 R 50,606 R 50,044

  1. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    6 Oregon - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S39. Summary statistics for natural gas - Oregon, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 0 0 0 0 0 Gas Wells R 28 R 24 R 24 R 12 14 Production (million cubic feet) Gross

  2. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    8 Pennsylvania - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S40. Summary statistics for natural gas - Pennsylvania, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 7,046 7,627 7,164 8,481 7,557 Gas Wells R 61,815 R 62,922 R 61,838 R

  3. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    6 Tennessee - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S44. Summary statistics for natural gas - Tennessee, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 52 75 NA NA NA Gas Wells R 1,027 R 1,027 1,089 NA NA Production (million cubic

  4. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    8 Texas - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S45. Summary statistics for natural gas - Texas, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 85,030 94,203 96,949 104,205 105,159 Gas Wells R 139,368 R 140,087 R 140,964 R 142,292

  5. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    0 Utah - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S46. Summary statistics for natural gas - Utah, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 3,119 3,520 3,946 4,249 3,966 Gas Wells R 7,603 R 8,121 R 8,300 R 8,537 8,739 Production

  6. Million Cu. Feet Percent of National Total

    Energy Information Administration (EIA) (indexed site)

    4 Virginia - Natural Gas 2015 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S48. Summary statistics for natural gas - Virginia, 2011-2015 2011 2012 2013 2014 2015 Number of Wells Producing Natural Gas at End of Year Oil Wells 2 1 1 2 2 Gas Wells R 7,781 R 7,874 7,956 R 8,061 8,111 Production (million

  7. Science DMZ Implemented at CU Boulder

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    CU Science Engagement Move your data Programs & Workshops Science Requirements Reviews Case Studies OSCARS Case Studies Science DMZ Case Studies Science DMZ @ UF Science DMZ @ CU Science DMZ @ Penn & VTTI Science DMZ @ NOAA Science DMZ @ NERSC Science DMZ @ ALS Multi-facility Workflow Case Study Contact Us Technical Assistance: 1 800-33-ESnet (Inside US) 1 800-333-7638 (Inside US) 1 510-486-7600 (Globally) 1 510-486-7607 (Globally) Report Network Problems: trouble@es.net Provide Web Site

  8. The Effects of Hydrothermal Agingon a Commercial Cu SCR Catalyst

    Energy.gov [DOE]

    Examines the effect of hydrothermal aging on the Nox reduction over a commercial Cu-zeolite SCR catalyst.

  9. Cu(II) promotes amyloid pore formation

    SciTech Connect

    Zhang, Hangyu; Rochet, Jean-Christophe; Stanciu, Lia A.

    2015-08-14

    The aggregation of α-synuclein is associated with dopamine neuron death in Parkinson's disease. There is controversy in the field over the question of which species of the aggregates, fibrils or protofibrils, are toxic. Moreover, compelling evidence suggested the exposure to heavy metals to be a risk of PD. Nevertheless, the mechanism of metal ions in promoting PD remains unclear. In this research, we investigated the structural basis of Cu(II) induced aggregation of α-synuclein. Using transmission electron microscopy experiments, Cu(II) was found to promote in vitro aggregation of α-synuclein by facilitating annular protofibril formation rather than fibril formation. Furthermore, neuroprotective baicalein disaggregated annular protofibrils accompanied by considerable decrease of β-sheet content. These results strongly support the hypothesis that annular protofibrils are the toxic species, rather than fibrils, thereby inspiring us to search novel therapeutic strategies for the suppression of the toxic annular protofibril formation. - Highlights: • Cu(II) promoted the annular protofibril formation of α-synuclein in vitro. • Cu(II) postponed the in vitro fibrillization of α-synuclein. • Neuroprotective baicalein disaggregated annular protofibrils.

  10. OPERATIONS AND PERFORMANCE OF RHIC AS A CU-CU COLLIDER.

    SciTech Connect

    PILAT, R.; AHRENS, L.; BAI, M.; BARTON, D.S.; ET AL.

    2005-05-16

    The 5th year of RHIC operations, started in November 2004 and expected to last till June 2005, consists of a physics run with Cu-Cu collisions at 100 GeV/u followed by one with polarized protons (pp) at 100 GeV [l]. We will address here the overall performance of the RHIC complex used for the first time as a Cu-Cu collider, and compare it with previous operational experience with Au, PP and asymmetric d-Au collisions. We will also discuss operational improvements, such as a {beta}* squeeze to 85cm in the high luminosity interaction regions from the design value of 1m, system improvements, machine performance and limitations, and address reliability and uptime issues.

  11. Formation of two-dimensional CuSe on Cu(111) at very low selenium coverage

    DOE PAGES [OSTI]

    Walen, Holly; Liu, Da -Jiang; Oh, Junepyo; Yang, Hyun Jin; Kim, Yousoo; Thiel, Patricia A.

    2016-05-09

    Here, using scanning tunneling microscopy (STM), we observe that adsorption of Se on Cu(111) produces islands with (√3 x √3)R30° structure, at Se coverages far below the structure's ideal coverage of 1/3 ML. Based on density functional theory (DFT), these islands cannot form due to attractive interactions between chemisorbed Se atoms. DFT shows that incorporating Cu atoms into the √3-Se lattice stabilizes the structure, which provides a plausible explanation for the experimental observations.

  12. Synthesis of CuO by Cu-CPPs with the determination of Cu(II) coordination modes from a novel complex of [Cu(terpyOH){sub 2}]·(HBTC)·2H{sub 2}O

    SciTech Connect

    Wang, Yu Chen, Gang Han, Li; Pei, Jian

    2013-10-15

    In this study, we investigated the synthesis of CuO microrods by simple calcination of copper-based coordination polymer particles (Cu-CPPs) at high temperature in air. The photocatalytic activity of the CuO microrods was tested by the decomposition of aqueous solution of RhB, which was completely decomposed by irradiation with light. To analyze the relationship of metal ions and ligands in the Cu-CPPs, the single crystal of [Cu(terpyOH){sub 2}]∙(HBTC)∙2H{sub 2}O (1) (terpyOH=4′-hydroxy-2,2′:6′,2″-terpyridine, BTC=1,3,5-benzene tricarboxylate) was first prepared and characterized by X-ray single crystal structural analysis. A variety of hydrogen bonds constructing the 3D complex structure in [Cu(terpyOH){sub 2}]∙(HBTC)∙2H{sub 2}O (1) were observed. - Graphical abstract: Demonstrating a general method to synthesize CuO microrods via simple calcination of Cu-CPPs and Cu(II) coordination modes from a novel complex of [Cu(terpyOH){sub 2}]∙(HBTC)·2H{sub 2}O constructed by hydrogen bonding. Display Omitted - Highlights: • The formation of microrods CuO from thermal treatment of Cu-CPPs through an “escape-by-crafty-scheme” strategy has been studied. • Determination of Cu(II) coordination modes in Cu-CPPs from a novel complex of [Cu(terpyOH){sub 2}]∙(HBTC) 2H{sub 2}O. • Invested the behave of hydrogen bonding to construct the 3D complex structure. • Commendable photodegradation performance was observed.

  13. Triaxial Stress Distributions in Cu / low-k Interconnect Features

    SciTech Connect

    C Murray; P Besser; E Ryan; J Jordan-Sweet

    2011-12-31

    The distribution of triaxial stresses within single damascene Cu/organosilicate interconnect structures as a function of linewidth, ranging from 45 to 250 nm, was measured using x-ray diffraction. Least-squares minimization techniques were employed to determine the volume-averaged stress tensors of the Cu features. Longitudinal Cu stress values increased for linewidths below 100 nm, while transverse stresses decreased with decreasing linewidth below 100 nm due to the interplay between the Cu microstructure and the feature geometry. Large tensile out-of-plane stresses were observed in all of the lines demonstrating the constraint imposed by the barrier layers that encapsulate the Cu.

  14. Bi-Se doped with Cu, p-type semiconductor

    DOEpatents

    Bhattacharya, Raghu Nath; Phok, Sovannary; Parilla, Philip Anthony

    2013-08-20

    A Bi--Se doped with Cu, p-type semiconductor, preferably used as an absorber material in a photovoltaic device. Preferably the semiconductor has at least 20 molar percent Cu. In a preferred embodiment, the semiconductor comprises at least 28 molar percent of Cu. In one embodiment, the semiconductor comprises a molar percentage of Cu and Bi whereby the molar percentage of Cu divided by the molar percentage of Bi is greater than 1.2. In a preferred embodiment, the semiconductor is manufactured as a thin film having a thickness less than 600 nm.

  15. Method of producing .sup.67 Cu

    DOEpatents

    O'Brien, Jr., Harold A.; Barnes, John W.; Taylor, Wayne A.; Thomas, Kenneth E.; Bentley, Glenn E.

    1984-01-01

    A method of producing carrier-free .sup.67 Cu by proton spallation combined with subsequent chemical separation and purification is disclosed. A target consisting essentially of pressed zinc oxide is irradiated with a high energy, high current proton beam to produce a variety of spallogenic nuclides, including .sup.67 Cu and other copper isotopes. The irradiated target is dissolved in a concentrated acid solution to which a palladium salt is added. In accordance with the preferred method, the spallogenic copper is twice coprecipitated with palladium, once with metallic zinc as the precipitating agent and once with hydrogen sulfide as the precipitating agent. The palladium/copper precipitate is then dissolved in an acid solution and the copper is separated from the palladium by liquid chromatography on an anion exchange resin.

  16. Method for producing /sup 67/Cu

    DOEpatents

    O'Brien, H.A. Jr.; Barnes, J.W.; Taylor, W.A.; Thomas, K.E.; Bentley, G.E.

    A method of producing carrier-free /sup 67/Cu by proton spallation combined with subsequent chemical separation and purification is disclosed. A target consisting essentially of pressed zinc oxide is irradiated with a high energy, high current proton beam to produce a variety of spallogenic nuclides, including /sup 67/Cu and other copper isotopes. The irradiated target is dissolved in a concentrated acid solution to which a palladium salt is added. In accordance with the preferred method, the spallogenic copper is twice coprecipitated with palladium, once with metallic zinc as the precipitating agent and once with hydrogen sulfide as the precipitating agent. The palladium/copper precipitate is then dissolved in an acid solution and the copper is separated from the palladium by liquid chromatography on an anion exchange resin.

  17. Synthesis of Cu{sub 2}O from CuO thin films: Optical and electrical properties

    SciTech Connect

    Murali, Dhanya S. Jain, Mahaveer K.; Subrahmanyam, A.; Kumar, Shailendra; Choudhary, R. J.; Wadikar, Avinash D.

    2015-04-15

    Hole conducting, optically transparent Cu{sub 2}O thin films on glass substrates have been synthesized by vacuum annealing (5×10{sup −6} mbar at 700 K for 1 hour) of magnetron sputtered (at 300 K) CuO thin films. The Cu{sub 2}O thin films are p-type and show enhanced properties: grain size (54.7 nm), optical transmission 72% (at 600 nm) and Hall mobility 51 cm{sup 2}/Vs. The bulk and surface Valence band spectra of Cu{sub 2}O and CuO thin films are studied by temperature dependent Hall effect and Ultra violet photo electron Spectroscopy (UPS). CuO thin films show a significant band bending downwards (due to higher hole concentration) than Cu{sub 2}O thin films.

  18. Theoretical investigation of structural properties of CuCl, CuBr and CuI compounds under hydrostatic pressure

    SciTech Connect

    Louhibi-Fasla, S.; Djabri, H. Rekab; Achour, H.; Kefif, K.

    2013-12-16

    We have applied a recent version of the full potential linear muffin-tin orbitals method (FPLMTO) to study the structural properties of copper halides CuX (X=Cl, Br, I) under high pressure using the generalized gradient approximation (GGA) for the exchange and correlation potential by Perdew et al. Results are given for lattice parameters, bulk modulus and its first derivatives in the wurtzite(B4), zinc-blende (B3), CsCl (B2), rock-salt (B1), and PbO (B10) structures. The results of these calculations are compared with the available theoretical and experimental data.

  19. Magnetic dipole moments of {sup 57,58,59}Cu

    SciTech Connect

    Cocolios, T. E.; Andreyev, A. N.; Bastin, B.; Bree, N.; Buescher, J.; Elseviers, J.; Gentens, J.; Huyse, M.; Kudryavtsev, Yu.; Pauwels, D.; Bergh, P. Van den; Van Duppen, P.; Sonoda, T.

    2010-01-15

    In-gas-cell laser spectroscopy of the isotopes {sup 57,58,59,63,65}Cu has been performed at the LISOL facility using the 244.164-nm optical transition from the atomic ground state of copper. A detailed discussion on the hyperfine structure of {sup 63}Cu is presented. The magnetic dipole moments of the isotopes {sup 57,58,59,65}Cu are extracted based on that of {sup 63}Cu. The new value mu=+0.479(13)mu{sub N} is proposed for {sup 58}Cu, consistent with that of a pip{sub 3/2} x nup{sub 3/2} ground-state configuration. Spin assignments for the radioactive isotopes {sup 57,58,59}Cu are confirmed. The isotope shifts between the different isotopes are also given and discussed.

  20. Multi-component Cu-Strengthened Steel Welding Simulations: Atom...

    Office of Scientific and Technical Information (OSTI)

    Steel Welding Simulations: Atom Probe Tomography and Synchrotron X-ray Diffraction Analyses Citation Details In-Document Search Title: Multi-component Cu-Strengthened Steel Welding ...

  1. Cu Migration in Polycrystalline CdTe Solar Cells

    SciTech Connect

    Guo, Da; Akis, Richard; Brinkman, Daniel; Sankin, Igor; Fang, Tian; Vasileska, Dragica; Ringhofer, Christian

    2014-03-12

    An impurity reaction-diffusion model is applied to Cu defects and related intrinsic defects in polycrystalline CdTe for a better understanding of Cu’s role in the cell level reliability of CdTe PV devices. The simulation yields transient Cu distributions in polycrystalline CdTe during solar cell processing and stressing. Preliminary results for Cu migration using available diffusivity and solubility data show that Cu accumulates near the back contact, a phenomena that is commonly observed in devices after back-contact processing or stress conditions.

  2. Understanding NOx SCR Mechanism and Activity on Cu/Chabazite...

    Office of Scientific and Technical Information (OSTI)

    Book: Understanding NOx SCR Mechanism and Activity on CuChabazite Structures throughout the Catalyst Life Cycle Citation Details In-Document Search Title: Understanding NOx SCR...

  3. Enhanced Photocatalytic Property of Cu Doped Sodium Niobate

    SciTech Connect

    Xu, Jianbin; Zhang, Feng; Sun, Bingyang; Du, Yingge; Li, Guoqiang; Zhang, Weifeng

    2015-09-29

    We investigate the photocatalytic activity of Cu doped NaNbO3 powder sample prepared by the modified polymer complex method. The photocatalytic activity of hydrogen evolution from methanol aqueous solution was improved by Cu 2.6 at% doping. The photocatalytic degradation of rhodamine B under visible light irradiation was enhanced in comparison with pure NaNbO3. Cu inctroduction improved the adsorption property of NaNbO3, judging from the Fourier transform infrared spectra. Moreover, the ultraviolet light excitation in Cu doped sample was found to accelerate the mineralized process.

  4. [Purification of {sup 67}Cu]. Progress report

    SciTech Connect

    DeNardo, S.J.

    1994-09-01

    This report documents progress made in several areas of research and describes results which have not yet been published. These areas include: Purification of {sup 67}Cu; Macrocyclic chelates for targeted therapy; Studies of biologic activation associated with molecular receptor increase and tumor response in ChL6/L6 protocol patients; Lym-1 single chain genetically engineered molecules; Analysis of molecular genetic coded messages to enhance tumor response; Human dosimetry and therapeutic human use radiopharmaceuticals; studies in phantoms; Quantitative SPECT; Preclinical studies; and Clinical studies.

  5. New Resolved Resonance Region Evaluation for 63Cu and 65Cu for Nuclear Criticality Safety Program

    SciTech Connect

    Sobes, Vladimir; Leal, Luiz C; Guber, Klaus H; Forget, Benoit; Kopecky, S.; Schillebeeckx, P.; Siegler, P.

    2014-01-01

    A new resolved resonance region evaluation of 63Cu and 65Cu was done in the energy region from 10-5 eV to 99.5 keV. The R-Matrix SAMMY method using the Reich-Moore approximation was used to create a new set of consistent resonance parameters. The new evaluation was based on three experimental transmission data sets; two measured at ORELA and one from MITR, and two radiative capture experimental data sets from GELINA. A total of 141 new resonances were identied for 63Cu and 117 for 65Cu. The corresponding set of external resonances for each isotope was based on the identied resonances above 99.5 keV from the ORELA transmission data. The negative external levels (bound levels) were determined to match the dierential thermal cross section measured at the MITR. Double dierential elastic scattering cross sections were calculated from the new set of resonance parameters. Benchmarking calculations were carried out on a set of ICSBEP benchmarks. This work is in support of the DOE Nuclear Criticality Safety Program.

  6. Unexpected crystal and magnetic structures in MnCu4In and MnCu4Sn

    SciTech Connect

    Provino, A.; Paudyal, D.; Fornasini, ML; Dhiman, I.; Dhar, SK.; Das, A.; Mudryk, Y.; Manfrinetti, P.; Pecharsky, VK

    2013-01-29

    We discovered a new compound MnCu4In with its own hexagonal structure type (hP12-P63mc, ternary ordered derivative of the hexagonal MgZn2-type) that becomes ferromagnetic at TC = 540 K. This transition temperature is higher than that found in the MnCu2In and MnCu2Sn alloys. In contrast, the homologous compound MnCu4Sn, which crystallizes in the cubic MgCu4Sn-type, orders antiferromagnetically with TN = 110 K. The neutron diffraction studies show ferromagnetic spin orientation in the {1 0 1} plane in MnCu4In with a magnetic moment of 4.5 ?B/Mn at 22 K, and a corresponding value of 4.7 ?B/Mn in the antiferromagnetic MnCu4Sn with propagation vector View the MathML source. The first-principles electronic structure calculations show that the unexpected difference in both magnetic and crystal structures of MnCu4In and MnCu4Sn is due to the difference in the Mn-3d bands and exchange interactions relating to different crystal anisotropy, coordination numbers, and interatomic distances.

  7. Non-uniform Aging on Super Duty Diesel Truck Aged Urea Cu/Zeolite...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Aging on Super Duty Diesel Truck Aged Urea CuZeolite SCR Catalysts Non-uniform Aging on Super Duty Diesel Truck Aged Urea CuZeolite SCR Catalysts CuZeolite SCR catalysts aged ...

  8. Antiferromagnetism in EuCu2As2 and EuCu1.82Sb2 single crystals

    DOE PAGES [OSTI]

    Anand, V. K.; Johnston, D. C.

    2015-05-07

    Single crystals of EuCu2As2 and EuCu2Sb2 were grown from CuAs and CuSb self-flux, respectively. The crystallographic, magnetic, thermal, and electronic transport properties of the single crystals were investigated by room-temperature x-ray diffraction (XRD), magnetic susceptibility χ versus temperature T, isothermal magnetization M versus magnetic field H, specific heat Cp(T), and electrical resistivity ρ(T) measurements. EuCu2As2 crystallizes in the body-centered tetragonal ThCr2Si2-type structure (space group I4/mmm), whereas EuCu2Sb2 crystallizes in the related primitive tetragonal CaBe2Ge2-type structure (space group P4/nmm). The energy-dispersive x-ray spectroscopy and XRD data for the EuCu2Sb2 crystals showed the presence of vacancies on the Cu sites, yielding themore » actual composition EuCu1.82Sb2. The ρ(T) and Cp(T) data reveal metallic character for both EuCu2As2 and EuCu1.82Sb2. Antiferromagnetic (AFM) ordering is indicated from the χ(T),Cp(T), and ρ(T) data for both EuCu2As2 (TN = 17.5 K) and EuCu1.82Sb2 (TN = 5.1 K). In EuCu1.82Sb2, the ordered-state χ(T) and M(H) data suggest either a collinear A-type AFM ordering of Eu+2 spins S = 7/2 or a planar noncollinear AFM structure, with the ordered moments oriented in the tetragonal ab plane in either case. This ordered-moment orientation for the A-type AFM is consistent with calculations with magnetic dipole interactions. As a result, the anisotropic χ(T) and isothermal M(H) data for EuCu2As2, also containing Eu+2 spins S = 7/2, strongly deviate from the predictions of molecular field theory for collinear AFM ordering and the AFM structure appears to be both noncollinear and noncoplanar.« less

  9. Function Specific Analysis of the Thermal Durability of Cu-Zeolite...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Function Specific Analysis of the Thermal Durability of Cu-Zeolite SCR Catalyst Function Specific Analysis of the Thermal Durability of Cu-Zeolite SCR Catalyst Presentation given ...

  10. Deactivation Mechanism of Cu/Zeolite SCR Catalyst Due to Reductive...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Mechanism of CuZeolite SCR Catalyst Due to Reductive Hydrothermal Aging Deactivation Mechanism of CuZeolite SCR Catalyst Due to Reductive Hydrothermal Aging Better control for ...

  11. Application of cluster-plus-glue-atom model to barrierless CuNiTi and CuNiTa films

    SciTech Connect

    Li, Xiaona, E-mail: lixiaona@dlut.edu.cn; Ding, Jianxin; Wang, Miao; Dong, Chuang [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Chu, Jinn P. [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China)

    2014-11-01

    To improve the thermal stability of copper and avoid its diffusion into surrounding dielectrics or interfacial reactions with them, the authors applied the cluster-plus-glue-atom model to investigate barrierless CuNiM (M?=?Ti or Ta) seed layers. The dissolution of the third element (Ti or Ta) in the Cu lattice with the aid of Ni significantly improved the thermal stability of the Cu seed layer. The appropriate M/Ni (M?=?Ti or Ta) ratio was selected to obtain a low resistivity: the resistivity was as low as 2.5??? cm for the (Ti{sub 1.5/13.5}Ni{sub 12/13.5}){sub 0.3}Cu{sub 99.7} film and 2.8??? cm for the (Ta{sub 1.1/13.1}Ni{sub 12/13.1}){sub 0.4}Cu{sub 99.6} film after annealing at 500?C for 1?h. After annealing at 500?C for 40?h, the two films remained stable without forming a Cu{sub 3}Si compound. The authors confirmed that the range of applications of the cluster-plus-glue-atom model could be extended. Therefore, a third element M with negative enthalpies of mixing with both Cu and Ni could be selected, under the premise that the mixing enthalpy of MNi is more negative than that of MCu.

  12. Conducting mechanisms of forming-free TiW/Cu{sub 2}O/Cu memristive devices

    SciTech Connect

    Yan, P.; Li, Y.; Hui, Y. J.; Zhong, S. J.; Zhou, Y. X.; Xu, L.; Liu, N.; Qian, H.; Sun, H. J. Miao, X. S.

    2015-08-24

    P-type Cu{sub 2}O is a promising CMOS-compatible candidate to fabricate memristive devices for next-generation memory, logic and neuromorphic computing. In this letter, the microscopic switching and conducting mechanisms in TiW/Cu{sub 2}O/Cu memristive devices have been thoroughly investigated. The bipolar resistive switching behaviors without an electro-forming process are ascribed to the formation and rupture of the conducting filaments composed of copper vacancies. In the low resistive state, the transport of electrons in the filaments follows Mott's variable range hopping theory. When the devices switch back to high resistive state, the coexistence of Schottky emission at the Cu/Cu{sub 2}O interface and electron hopping between the residual filaments is found to dominate the conducting process. Our results will contribute to the further understanding and optimization of p-type memristive materials.

  13. How to stabilize highly active Cu+ cations in a mixed-oxide catalyst

    DOE PAGES [OSTI]

    Mudiyanselage, Kumudu; Luo, Si; Kim, Hyun You; Yang, Xiaofang; Baber, Ashleigh E.; Hoffmann, Friedrich M.; Senanayake, Sananayake; Rodriguez, Jose A.; Chen, Jingguang G.; Liu, Ping; et al

    2015-09-12

    Mixed-metal oxides exhibit novel properties that are not present in their isolated constituent metal oxides and play a significant role in heterogeneous catalysis. In this study, a titanium-copper mixed-oxide (TiCuOx) film has been synthesized on Cu(111) and characterized by complementary experimental and theoretical methods. At sub-monolayer coverages of titanium, a Cu2O-like phase coexists with TiCuOx and TiOx domains. When the mixed-oxide surface is exposed at elevated temperatures (600–650 K) to oxygen, the formation of a well-ordered TiCuOx film occurs. Stepwise oxidation of TiCuOx shows that the formation of the mixed-oxide is faster than that of pure Cu2O. As the Timore » coverage increases, Ti-rich islands (TiOx) form. The adsorption of CO has been used to probe the exposed surface sites on the TiOx–CuOx system, indicating the existence of a new Cu+ adsorption site that is not present on Cu2O/Cu(111). Adsorption of CO on Cu+ sites of TiCuOx is thermally more stable than on Cu(111), Cu2O/Cu(111) or TiO2(110). The Cu+ sites in TiCuOx domains are stable under both reducing and oxidizing conditions whereas the Cu2O domains present on sub-monolayer loads of Ti can be reduced or oxidized under mild conditions. Furthermore, the results presented here demonstrate novel properties of TiCuOx films, which are not present on Cu(111), Cu2O/Cu(111), or TiO2(110), and highlight the importance of the preparation and characterization of well-defined mixed-metal oxides in order to understand fundamental processes that could guide the design of new materials.« less

  14. Photoelectrochemistry, Electronic Structure, and Bandgap Sizes of Semiconducting Cu(I)-Niobates and Cu(I)-Tantalates

    SciTech Connect

    Maggard, Paul A.

    2013-11-14

    Semiconducting metal-oxides have remained of intense research interest owing to their potential for achieving efficient solar-driven photocatalytic reactions in aqueous solutions that occur as a result of their bandgap excitation. The photocatalytic reduction of water or carbon dioxide to generate hydrogen or hydrocarbon fuels, respectively, can be driven on p-type (photocathodic) electrodes with suitable band energies. However, metal-oxide semiconductors are typically difficult to dope as p-type with a high mobility of carriers. The supported research led to the discovery of new p-type Cu(I)-niobate and Cu(I)-tantalate film electrodes that can be prepared on FTO glass. New high-purity flux syntheses and the full structural determination of several Cu(I)-containing niobates and tantalates have been completed, as well as new investigations of their optical and photoelectrochemical properties and electronic structures via density-functional theory calculations. For example, CuNbO3, Cu5Ta11O30 and CuNb3O8 were prepared in high purity and their structures were characterized by both single-crystal and powder X-ray diffraction techniques. These two classes of Cu(I)-containing compounds exhibit optical bandgap sizes ranging from ~1.3 eV to ~2.6 eV. Photoelectrochemical measurements of these compounds show strong photon-driven cathodic currents that confirm the p-type semiconductor behavior of CuNbO3, CuNb3O8, and Cu5Ta11O30. Incident-photon-to-current efficiencies are measured that approach greater than ~1%. Electronic-structure calculations based on density functional theory reveal the visible-light absorption stems from a nearly-direct bandgap transition involving a copper-to-niobium or tantalum (d10 to d0) charge-transfer excitations.

  15. Structure and electrochemical properties of nanometer Cu substituted ?-nickel hydroxide

    SciTech Connect

    Bao, Jie; Zhu, Yanjuan; Zhang, Zhongju; Xu, Qingsheng; Zhao, Weiren; Chen, Jian; Zhang, Wei; Han, Quanyong

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ? Cu substituted ?-nickel hydroxide was prepared by ultrasonic assisted precipitation. ? The XRD peaks are anisotropic broadening. ? The electrode for 0.9 wt.% Cu has the highest capacity of 310 mAh/g at 0.2 C. -- Abstract: Nanometer Cu-substituted ?-nickel hydroxide was synthesized by means of ultrasonic-assisted precipitation. Particle size distribution (PSD) measurement, X-ray diffraction (XRD), and high-resolution transmission electron microscope (HR-TEM) were used to characterize the physical properties of the synthesized samples. The results indicate that the average particle size of the samples is about 96110 nm and the XRD diffraction peaks are anisotropic broadening. The crystal grains are mainly polycrystal structure with columnar or needle-like morphology, containing many defects. With increase of Cu content, the shape of primary particles transform from columnar to needle-like. The influences of doping amounts of Cu on the electrochemical performance were investigated through constant current charge/discharge and cyclic voltammetric measurements. The specific capacity increases initially and then decreases with increasing Cu-doping ratio, the electrode C containing 0.9 wt.% Cu shows the maximum discharge capacity of 310 mAh/g at 0.2 C, and it has the lowest charging voltage, higher discharge voltage plateau, better cycle performance and larger proton diffusion coefficient than the other electrodes.

  16. Manipulating Stress in Cu/low-k Dielectric Nanocomposites

    SciTech Connect

    C Murray; P Besser; E Ryan; J Jordan-Sweet

    2011-12-31

    The interaction of x-rays with organic dielectric materials, which alters their mechanical properties, affects values of stress generated within encapsulated Cu structures. In particular, the evolution of stress within submicron Cu interconnect structures encapsulated by an organosilicate glass can be investigated in situ using synchrotron-based x-ray diffraction. The overall geometry of the composite, along with the amount of irradiation, dictates the change in stress of the Cu features. A quantitative comparison of these findings to mechanical modeling results reveals two modes of modification within the dielectric film: a densification that changes the effective eigenstrain followed by an increase in elastic modulus.

  17. Coupled skyrmion sublattices in Cu2OSeO3

    SciTech Connect

    Langner, M.C.; Roy,, S.; Mishra, S. K.; Lee, J. C. T.; Shi,, X. W.; Hossain, M. A.; Chuang, Y.-D.; Seki, S.; Tokura, Y.; Kevan, S. D.; Schoenlein, R. W.

    2014-04-18

    We report the observation of a skyrmion lattice in the chiral multiferroic insulator Cu2OSeO3 using Cu L3-edge resonant soft x-ray diffraction. We observe the unexpected existence of two distinct skyrmion sub-lattices that arise from inequivalent Cu sites with chemically identical coordination numbers but different magnetically active orbitals . The skyrmion sublattices are rotated with respect to each other implying a long wavelength modulation of the lattice. The modulation vector is controlled with an applied magnetic field, associating this Moir'e-like phase with a continuous phase transition. Our findings will open a new class of science involving manipulation of quantum topological states.

  18. Role of Cu-Ion Doping in Cu-α-MnO2 Nanowire Electrocatalysts for the Oxygen Reduction Reaction

    DOE PAGES [OSTI]

    Davis, Danae J.; Lambert, Timothy N.; Vigil, Julian A.; Rodriguez, Mark A.; Brumbach, Michael T.; Coker, Eric N.; Limmer, Steven J.

    2014-07-09

    The role of Cu-ion doping in α-MnO2 electrocatalysts for the oxygen reduction reaction in alkaline electrolyte was investigated. Copper doped α-MnO2 nanowires (Cu-α-MnO2) were prepared with varying amounts of Cu2+ using a solvothermal method. The electrocatalytic dataindicates that Cu-α-MnO2 nanowires have higher terminal current densities, enhanced kinetic rate constants, and improved charge transfer resistances that trend with Cu-content, exceeding values attained by α-MnO2 alone. The observed improvement in catalytic behavior correlates with an increase in Mn3+ content for the Cu-α-MnO2 nanowires. The Mn3+/Mn4+ couple is themediator for the rate-limiting redox driven O2-/OH- exchange. It is proposed that O2 adsorbs viaanmore » axial site (the eg orbital on the Mn3+ d4 ion) at the surface, or at edge defects, of the nanowireand that the increase in covalent nature of the nanowire with Cu-ion doping leads to stabilization of O2 adsorbates and faster rates of reduction. This work is applicable to other manganese oxide electrocatalysts and shows for the first time there is a correlation for manganese oxides between electrocatalytic activity for the ORR in alkaline electrolyte and an increase in Mn3+ character of the oxide.« less

  19. Crystallization of Zr2PdxCu(1-x) and Zr2NixCu(1-x) Metallic Glass

    SciTech Connect

    Min Xu

    2008-08-18

    One interesting aspect of rretallic glasses is the numerous instances of the deviation of the phase selection from the amorphous state to thermodynamically stable phases during the crystallization process. Their devitrification pathways allow us to study the relationship between the original amorphous structure and their crystalline counter parts. Among the various factors of phase selections, size and electronic effects have been most extensively studied. Elucidating the phase selection process of a glassy alloy will be helpful to fill in the puzzle of the changes from disordered to ordered structures. In this thesis, Two model Zr{sub 2}Pd{sub x}Cu{sub (1-x)} and Zr{sub 2}Ni{sub x}Cu{sub (1-x)} (x = 0, 0.25, 0.5, 0.75 and 1) glassy systems were investigated since: (1) All of the samples can be made into a homogenous metallic glass; (2) The atomic radii differ from Pd to Cu is by 11%, while Ni has nearly the identical atomic size compare to Cu. Moreover, Pd and Ni differ by only one valence electron from Cu. Thus, these systems are ideal to test the idea of the effects of electronic structure and size factors; (3) The small number of components in these pseudo binary systems readily lend themselves to theoretical modeling. Using high temperature X-ray diffraction {HTXRD) and thermal analysis, topological, size, electronic, bond and chemical distribution factors on crystallization selections in Zr{sub 2}Pd{sub x}Cu{sub (1-x)} and Zr{sub 2}Ni{sub x}Cu{sub (1-x)} metallic glass have been explored. All Zr{sub 2}Pd{sub x}Cu{sub (1-x)} compositions share the same Cu11b phase with different pathways of meta-stable, icosahedral quasicrystalline phase (i-phase), and C16 phase formations. The quasicrystal phase formation is topologically related to the increasing icosahedral short range order (SRO) with Pd content in Zr{sub 2}Pd{sub x}Cu{sub (1·x)} system. Meta-stable C16 phase is competitive with C11b phase at x = 0.5, which is dominated by electronic structure rather than

  20. Improving properties of Mg with AlCu additions

    SciTech Connect

    Rashad, Muhammad; Pan, Fusheng; Asif, Muhammad; Hussain, Shahid; Saleem, Muhammad

    2014-09-15

    The present work reports improvement in tensile properties of the Mg matrix reinforced with micron-sized copperaluminum particulate hybrids. The AlCu particulate hybrids were incorporated into the Mg matrix through powder metallurgy method. The synthesized alloys exhibited homogeneously dispersed Mg{sub 2}Cu particles in the matrix, therefore leading to a 110% increase in yield strength (221 MPa) and a 72% enhancement in ultimate tensile strength (284 MPa) by addition of 1.0 wt.%Al0.6 wt.%Cu particle hybrids. Optical microscopy, scanning election microscopy, transmission electron microscopy and X-ray diffraction were used to investigate the microstructure and intermetallic phases of the synthesized alloys. - Highlights: Mg matrix is reinforced with AlCu particulate hybrids. Powder metallurgic method is used to fabricate the alloys. Tensile strength and ductility were increased simultaneously.

  1. Impact of the Stack Order in Cu-Zn-Sn Metal Precursors on the Properties of

    Office of Scientific and Technical Information (OSTI)

    Cu2ZnSnS4 Thin Films (Conference) | SciTech Connect Impact of the Stack Order in Cu-Zn-Sn Metal Precursors on the Properties of Cu2ZnSnS4 Thin Films Citation Details In-Document Search Title: Impact of the Stack Order in Cu-Zn-Sn Metal Precursors on the Properties of Cu2ZnSnS4 Thin Films Cu2ZnSnS4 (CZTS) thin films were grown by the annealing of metallic precursors with different stack orders in sulfur atmosphere. The sequential deposition of the metal layers from single Cu, Zn, and Sn

  2. Characteristics of Cu stabilized Nb3Al strands with low Cu ratio

    SciTech Connect

    Kikuchi, A.; Yamada, R.; Barzi, E.; Kobayashi, M.; Lamm, M.; Nakagawa, K.; Sasaki, K.; Takeuchi, T.; Turrioni, D.; Zlobin, A.V.; /NIMC, Tsukuba /Fermilab /Hitachi, Tsuchiura Works /KEK, Tsukuba

    2008-12-01

    Characteristics of recently developed F4-Nb{sub 3}Al strand with low Cu ratio are described. The overall J{sub c} of the Nb{sub 3}Al strand could be easily increased by decreasing of the Cu ratio. Although the quench of a pulse-like voltage generation is usually observed in superconducting unstable conductor, the F4 strand with a low Cu ratio of 0.61 exhibited an ordinary critical transition of gradual voltage generation. The F4 strand does not have magnetic instabilities at 4.2 K because of the tantalum interfilament matrix. The overall J{sub c} of the F4 strand achieved was 80-85% of the RRP strand. In the large mechanical stress above 100 MPa, the overall J{sub c} of the F4 strand might be comparable to that of high J{sub c} RRP-Nb{sub 3}Sn strands. The Rutherford cable with a high packing factor of 86.5% has been fabricated using F4 strands. The small racetrack magnet, SR07, was also fabricated by a 14 m F4 cable. The quench current, I{sub q}, of SR07 were obtained 22.4 kA at 4.5 K and 25.2 kA at 2.2 K. The tantalum matrix Nb{sub 3}Al strands are promising for the application of super-cooled high-field magnets as well as 4.2 K operation magnets.

  3. Cu--Pd--M hydrogen separation membranes

    DOEpatents

    Do{hacek over }an, Omer N; Gao, Michael C; Young, Rongxiang Hu; Tafen, De Nyago

    2013-12-17

    The disclosure provides an H2 separation membrane comprised of an allow having the composition Cu.Sub.(100-x-y)Pd.sub.xM.sub.y, where x is from about 35 to about 50 atomic percent and where y is from greater than 0 to about 20 atomic percent, and where M consists of magnesium, yttrium, aluminum, titanium, lanthanum, or combinations thereof. The M elements act as strong stabilizers for the B2 phase of the allow, and extend the critical temperature of the alloy for a given hydrogen concentration and pressure. Due to the phase stabilization and the greater temperature range over which a B2 phase can be maintained, the allow is well suited for service as a H2 separation membrane, particularly when applicable conditions are established or cycled above about 600.degree. C. over the course of expected operations. In certain embodiments, the B2 phase comprises at least 60 estimated volume percent of the allow at a steady-state temperature of 400.degree. C. The B2 phase stability is experimentally validated through HT-XRD.

  4. Modified Ni-Cu catalysts for ethanol steam reforming

    SciTech Connect

    Dan, M.; Mihet, M.; Almasan, V.; Borodi, G.; Katona, G.; Muresan, L.; Lazar, M. D.

    2013-11-13

    Three Ni-Cu catalysts, having different Cu content, supported on γ-alumina were synthesized by wet co-impregnation method, characterized and tested in the ethanol steam reforming (ESR) reaction. The catalysts were characterized for determination of: total surface area and porosity (N{sub 2} adsorption - desorption using BET and Dollimer Heal methods), Ni surface area (hydrogen chemisorption), crystallinity and Ni crystallites size (X-Ray Diffraction), type of catalytic active centers (Hydrogen Temperature Programmed Reduction). Total surface area and Ni crystallites size are not significantly influenced by the addition of Cu, while Ni surface area is drastically diminished by increasing of Cu concentration. Steam reforming experiments were performed at atmospheric pressure, temperature range 150-350°C, and ethanol - water molar ration of 1 at 30, using Ar as carrier gas. Ethanol conversion and hydrogen production increase by the addition of Cu. At 350°C there is a direct connection between hydrogen production and Cu concentration. Catalysts deactivation in 24h time on stream was studied by Transmission Electron Microscopy (TEM) and temperature-programmed reduction (TPR) on used catalysts. Coke deposition was observed at all studied temperatures; at 150°C amorphous carbon was evidenced, while at 350°C crystalline, filamentous carbon is formed.

  5. Comparison of plasma temperature and electron density on nanosecond laser ablation of Cu and nano-Cu

    SciTech Connect

    Chen, Anmin; Jiang, Yuanfei; Wang, Tingfeng; Shao, Junfeng; Jin, Mingxing

    2015-03-15

    Laser-induced breakdown spectroscopy is performed through the collection of spectra by spectral detection equipment at different delay times and distances from targets composed of Cu and nano-Cu, which are ablated using a Nd:YAG laser (532 nm, 10 ns, 10 Hz) in our experiments. The measured wavelength range is from 475 nm to 525 nm. Using the local thermodynamic equilibrium model, we analyze the characteristics of the plasma temperature and the electron number density for different distances between the target surface and the lens. The results show that when compared with the nano-Cu plasma case, the temperature of the Cu plasma is higher, while its electron number density is lower.

  6. Growth, characterization and electrochemical properties of hierarchical CuO nanostructures for supercapacitor applications

    SciTech Connect

    Krishnamoorthy, Karthikeyan; Kim, Sang-Jae

    2013-09-01

    Graphical abstract: - Highlights: Hierarchical CuO nanostructures were grown on Cu foil. Monoclinic phase of CuO was grown. XPS analysis revealed the presence of Cu(2p{sub 3/2}) and Cu(2p{sub 1/2}) on the surfaces. Specific capacitance of 94 F/g was achieved for the CuO using cyclic voltammetry. Impedance spectra show their pseudo capacitor applications. - Abstract: In this paper, we have investigated the electrochemical properties of hierarchical CuO nanostructures for pseudo-supercapacitor device applications. Moreover, the CuO nanostructures were formed on Cu substrate by in situ crystallization process. The as-grown CuO nanostructures were characterized using X-ray diffraction (XRD), Fourier transform-infra red spectroscopy (FT-IR), X-ray photoelectron spectroscopy and field emission-scanning electron microscope (FE-SEM) analysis. The XRD and FT-IR analysis confirm the formation of monoclinic CuO nanostructures. FE-SEM analysis shows the formation of leave like hierarchical structures of CuO with high uniformity and controlled density. The electrochemical analysis such as cyclic voltammetry and electrochemical impedance spectroscopy studies confirms the pseudo-capacitive behavior of the CuO nanostructures. Our experimental results suggest that CuO nanostructures will create promising applications of CuO toward pseudo-supercapacitors.

  7. Analysis of the structure, configuration, and sizing of Cu and Cu oxide nanoparticles generated by fs laser ablation of solid target in liquids

    SciTech Connect

    Santillan, J. M. J.; Videla, F. A.; Schinca, D. C.; Scaffardi, L. B.; Fernandez van Raap, M. B.

    2013-04-07

    We report on the analysis of structure, configuration, and sizing of Cu and Cu oxide nanoparticles (Nps) produced by femtosecond (fs) laser ablation of solid copper target in liquids. Laser pulse energy ranged between 500 {mu}J and 50 {mu}J. Water and acetone were used to produce the colloidal suspensions. The study was performed through optical extinction spectroscopy using Mie theory to fit the full experimental spectra, considering free and bound electrons size dependent contributions to the metal dielectric function. Raman spectroscopy and AFM technique were also used to characterize the sample. Considering the possible oxidation of copper during the fabrication process, two species (Cu and Cu{sub 2}O) arranged in two structures (bare core or core-shell) and in two configuration types (Cu-Cu{sub 2}O or Cu{sub 2}O-Cu) were considered for the fitting depending on the laser pulse energy and the surrounding media. For water at high energy, it can be observed that a Cu-Cu{sub 2}O configuration fits the experimental spectra of the colloidal suspension, while for decreasing energy and below a certain threshold, a Cu{sub 2}O-Cu configuration needs to be included for the optimum fit. Both species coexist for energies below 170 {mu}J for water. On the other hand, for acetone at high energy, optimum fit of the full spectrum suggests the presence a bimodal Cu-Cu{sub 2}O core-shell Nps distribution while for decreasing energy and below a 70 {mu}J threshold energy value, Cu{sub 2}O-Cu core-shell Nps must be included, together with the former configuration, for the fit of the full spectrum. We discuss possible reasons for the changes in the structural configuration of the core-shell Nps.

  8. Magnetic dipole moments of {sup 58}Cu and {sup 59}Cu by in-source laser spectroscopy

    SciTech Connect

    Stone, N. J.; Koester, U.; Stone, J. Rikovska; Fedorov, D. V.; Fedoseyev, V. N.; Flanagan, K. T.; Hass, M.; Lakshmi, S.

    2008-06-15

    Online measurements of the magnetic dipole moments and isotope shifts of {sup 58}Cu and {sup 59}Cu by the in-source laser spectroscopy method are reported. The results for the magnetic moments are {mu} ({sup 58}Cu) =+0.52(8) {mu}{sub N},{mu}({sup 59}Cu) =+1.84(3) {mu}{sub N} and for the isotope shifts {delta}{nu}{sup 59,65}=1.72(22) GHz and {delta}{nu}{sup 58,65}=1.99(30) GHz in the transition from the 3d{sup 10}4s {sup 2}S{sub 1/2} ground state to the 3d{sup 10}4p {sup 2}P{sub 1/2} state in Cu I. The magnetic moment of {sup 58}Cu is discussed in the context of the strength of the subshell closure at {sup 56}Ni, additivity rules and large-scale shell model calculations.

  9. Subcellular metal imaging identifies dynamic sites of Cu accumulation in Chlamydomonas

    DOE PAGES [OSTI]

    Hong-Hermesdorf, Anne; Miethke, Marcus; Gallaher, Sean D.; Kropat, Janette; Dodani, Sheel C.; Chan, Jefferson; Barupala, Dulmini; Domaille, Dylan W.; Shirasaki, Dyna I.; Loo, Joseph A.; et al

    2014-10-26

    Here we identified a Cu-accumulating structure with a dynamic role in intracellular Cu homeostasis. During Zn limitation, Chlamydomonas reinhardtii hyperaccumulates Cu, a process dependent on the nutritional Cu sensor CRR1, but it is functionally Cu deficient. Visualization of intracellular Cu revealed major Cu accumulation sites coincident with electron-dense structures that stained positive for low pH and polyphosphate, suggesting that they are lysosome-related organelles. Nano-secondary ion MS showed colocalization of Ca and Cu, and X-ray absorption spectroscopy was consistent with Cu+ accumulation in an ordered structure. Zn resupply restored Cu homeostasis concomitant with reduced abundance of these structures. Cu isotope labelingmore » demonstrated that sequestered Cu+ became bioavailable for the synthesis of plastocyanin, and transcriptome profiling indicated that mobilized Cu became visible to CRR1. Cu trafficking to intracellular accumulation sites may be a strategy for preventing protein mismetallation during Zn deficiency and enabling efficient cuproprotein metallation or remetallation upon Zn resupply.« less

  10. Subcellular metal imaging identifies dynamic sites of Cu accumulation in Chlamydomonas

    SciTech Connect

    Hong-Hermesdorf, Anne; Miethke, Marcus; Gallaher, Sean D.; Kropat, Janette; Dodani, Sheel C.; Chan, Jefferson; Barupala, Dulmini; Domaille, Dylan W.; Shirasaki, Dyna I.; Loo, Joseph A.; Weber, Peter K.; Pett-Ridge, Jennifer; Stemmler, Timothy L.; Chang, Christopher J.; Merchant, Sabeeha S.

    2014-10-26

    Here we identified a Cu-accumulating structure with a dynamic role in intracellular Cu homeostasis. During Zn limitation, Chlamydomonas reinhardtii hyperaccumulates Cu, a process dependent on the nutritional Cu sensor CRR1, but it is functionally Cu deficient. Visualization of intracellular Cu revealed major Cu accumulation sites coincident with electron-dense structures that stained positive for low pH and polyphosphate, suggesting that they are lysosome-related organelles. Nano-secondary ion MS showed colocalization of Ca and Cu, and X-ray absorption spectroscopy was consistent with Cu+ accumulation in an ordered structure. Zn resupply restored Cu homeostasis concomitant with reduced abundance of these structures. Cu isotope labeling demonstrated that sequestered Cu+ became bioavailable for the synthesis of plastocyanin, and transcriptome profiling indicated that mobilized Cu became visible to CRR1. Cu trafficking to intracellular accumulation sites may be a strategy for preventing protein mismetallation during Zn deficiency and enabling efficient cuproprotein metallation or remetallation upon Zn resupply.

  11. Processing of R-Ba-Cu-O superconductors

    SciTech Connect

    Wu, H.

    1998-02-23

    Precipitation processes were developed to introduce second phases as flux pinning centers in Gd-Ba-Cu-O and Nd-Ba-Cu-O superconductors. In Gd-Ba-Cu-O, precipitation is caused by the decrease of the upper solubility limit of Gd{sub 1+x}Ba{sub 2{minus}x}Cu{sub 3}O{sub 7} solid solution (Gd123ss) in low oxygen partial pressure. Processing of supersaturated Gd{sub 1.2}Ba{sub 1.8}Cu{sub 3}O{sub 7} in low oxygen partial pressure can produce dispersed second phases. Gd211 is formed as a separate phase while extensive Gd124 type stacking fault is formed instead of a separate CuO phase. As a result of the precipitation reaction, the transition temperature and critical current density are increased. In Nd-Ba-Cu-O, precipitation is caused by the decrease of the lower solubility limit of Nd{sub 1+x}Ba{sub 2{minus}x}Cu{sub 3}O{sub 7} solid solution (Nd123ss) in oxygen. DTA results reveal the relative stability of Nd123ss in different oxygen partial pressures. In 1 bar oxygen partial pressure, Nd123ss with x = 0.1 is the most stable phase. In lower oxygen partial pressures, the most stable composition shifts towards the stoichiometric composition. The relative stability changes faster with decreasing oxygen partial pressure. Therefore, processing in oxygen and air tends to produce broad superconducting transitions but sharp transitions can be achieved in 0.01 bar and 0.001 bar oxygen partial pressures. While the lower solubility limits in 0.01 bar and 0.001 bar oxygen partial pressures remain at x = 0.00, the solubility limits in oxygen and air show a narrowing with decreasing temperature. Because of the narrowing of the solubility range in oxygen, oxygen annealing of Nd123 initially processed in low oxygen partial pressures will result in precipitation of second phases. The equilibrium second phase is BaCuO{sub 2} for temperature above 608 C, and at lower temperatures the equilibrium second phases are Ba{sub 2}CuO{sub 3.3} and Ba{sub 2}Cu{sub 3}O{sub 5+y}. However, annealing at

  12. Thermoelectric properties of chalcopyrite type CuGaTe{sub 2} and chalcostibite CuSbS{sub 2}

    SciTech Connect

    Kumar Gudelli, Vijay; Kanchana, V.; Vaitheeswaran, G.; Svane, A.; Christensen, N. E.

    2013-12-14

    Electronic and transport properties of CuGaTe{sub 2}, a hole-doped ternary copper based chalcopyrite type semiconductor, are studied using calculations within the Density Functional Theory and solving the Boltzmann transport equation within the constant relaxation time approximation. The electronic band structures are calculated by means of the full-potential linear augmented plane wave method, using the Tran-Blaha modified Becke-Johnson potential. The calculated band gap of 1.23 eV is in agreement with the experimental value of 1.2 eV. The carrier concentration- and temperature dependent thermoelectric properties of CuGaTe{sub 2} are derived, and a figure of merit of zT = 1.69 is obtained at 950 K for a hole concentration of 3.7·10{sup 19} cm{sup −3}, in agreement with a recent experimental finding of zT = 1.4, confirming that CuGaTe{sub 2} is a promising material for high temperature thermoelectric applications. The good thermoelectric performance of p-type CuGaTe{sub 2} is associated with anisotropic transport from a combination of heavy and light bands. Also for CuSbS{sub 2} (chalcostibite), a better performance is obtained for p-type than for n-type doping. The variation of the thermopower as a function of temperature and concentration suggests that CuSbS{sub 2} will be a good thermoelectric material at low temperatures, similarly to the isostructural CuBiS{sub 2} compound.

  13. Ab initio molecular dynamics simulations of short-range order in Zr50Cu45Al5 and Cu50Zr45Al5 metallic glasses

    DOE PAGES [OSTI]

    Huang, Yuxiang; Huang, Li; Wang, C. Z.; Kramer, M. J.; Ho, K. M.

    2016-02-01

    Comparative analysis between Zr-rich Zr50Cu45Al5 and Cu-rich Cu50Zr45Al5 metallic glasses (MGs) is extensively performed to locate the key structural motifs accounting for their difference of glass forming ability. Here we adopt ab initio molecular dynamics simulations to investigate the local atomic structures of Zr50Cu45Al5 and Cu50Zr45Al5 MGs. A high content of icosahedral-related (full and distorted) orders was found in both samples, while in the Zr-rich MG full icosahedrons < 0,0,12,0 > is dominant, and in the Cu-rich one the distorted icosahedral orders, especially < 0,2,8,2 > and < 0,2,8,1 >, are prominent. And the < 0,2,8,2 > polyhedra in Cu50Zr45Al5more » MG mainly originate from Al-centered clusters, while the < 0,0,12,0 > in Zr50Cu45Al5 derives from both Cu-centered clusters and Al-centered clusters. These difference may be ascribed to the atomic size difference and chemical property between Cu and Zr atoms. Lastly, the relatively large size of Zr and large negative heat of mixing between Zr and Al atoms, enhancing the packing density and stability of metallic glass system, may be responsible for the higher glass forming ability of Zr50Cu45Al5.« less

  14. Ab initio molecular dynamics simulations of short-range order in Zr50Cu45Al5 and Cu50Zr45Al5 metallic glasses

    DOE PAGES [OSTI]

    Huang, Yuxiang; Huang, Li; Wang, C. Z.; Kramer, M. J.; Ho, K. M.

    2016-02-01

    In this study, comparative analysis between Zr-rich Zr50Cu45Al5 and Cu-rich Cu50Zr45Al5 metallic glasses (MGs) is extensively performed to locate the key structural motifs accounting for their difference of glass forming ability. Here we adopt ab initio molecular dynamics simulations to investigate the local atomic structures of Zr50Cu45Al5 and Cu50Zr45Al5 MGs. A high content of icosahedral-related (full and distorted) orders was found in both samples, while in the Zr-rich MG full icosahedrons <0,0,12,0> is dominant, and in the Cu-rich one the distorted icosahedral orders, especially <0,2,8,2> and <0,2,8,1>, are prominent. And the <0,2,8,2> polyhedra in Cu50Zr45Al5 MG mainly originate from Al-centeredmore » clusters, while the <0,0,12,0> in Zr50Cu45Al5 derives from both Cu-centered clusters and Al-centered clusters. These difference may be ascribed to the atomic size difference and chemical property between Cu and Zr atoms. The relatively large size of Zr and large negative heat of mixing between Zr and Al atoms, enhancing the packing density and stability of metallic glass system, may be responsible for the higher glass forming ability of Zr50Cu45Al5.« less

  15. Thermodynamic understanding of Sn whisker growth on the Cu surface in Cu(top)-Sn(bottom) bilayer system upon room temperature aging

    SciTech Connect

    Huang, Lin; Jian, Wei; Lin, Bing; Wang, Jiangyong; Wen, Yuren; Gu, Lin

    2015-06-07

    Sn whiskers are observed by scanning electron microscope on the Cu surface in Cu(top)-Sn(bottom) bilayer system upon room temperature aging. Only Cu{sub 6}Sn{sub 5} phase appears in the X-ray diffraction patterns and no Sn element is detected in the Cu sublayer by scanning transmission electron microscopy. Based on the interfacial thermodynamics, the intermetallic Cu{sub 6}Sn{sub 5} compound phase may form directly at the Sn grain boundary. Driven by the stress gradient during the formation of Cu{sub 6}Sn{sub 5} compound at Sn grain boundaries, Sn atoms segregate onto the Cu surface and accumulate to form Sn whisker.

  16. Extracting Cu Diffusion Parameters in Polycrystalline CdTe

    SciTech Connect

    Akis, Richard; Brinkman, Daniel; Sankin, Igor; Fang, Tian; Guo, Da; Dragica, Vasileska; Ringhofer, Christian

    2014-06-13

    It is well known that Cu plays an important role in CdTe solar cell performance as a dopant. In this work, a finite-difference method is developed and used to simulate Cu diffusion in CdTe solar cells. In the simulations, which are done on a two-dimensional (2D) domain, the CdTe is assumed to be polycrystal-line, with the individual grains separated by grain boundaries. When used to fit experimental Cu concentration data, bulk and grain boundary diffusion coefficients and activation energies for CdTe can be extracted. In the past, diffusion coefficients have been typically obtained by fitting data to simple functional forms of limited validity. By doing full simulations, the simplifying assumptions used in those analytical models are avoided and diffusion parameters can thus be determined more accurately.

  17. A Window on Surface Explosions: Tartaric Acid on Cu(110)

    SciTech Connect

    Mhatre, B S; Pushkarev, V; Holsclaw, B; Lawton, T J; Sykes, E C. H.; Gellman, A J

    2013-04-18

    Autocatalytic reaction mechanisms are observed in a range of important chemical processes including catalysis, radical-mediated explosions, and biosynthesis. Because of their complexity, the microscopic details of autocatalytic reaction mechanisms have been difficult to study on surfaces and heterogeneous catalysts. Autocatalytic decomposition reactions of S,S- and R,R-tartaric acid (TA) adsorbed on Cu(110) offer molecular-level insight into aspects of these processes, which until now, were largely a matter of speculation. The decomposition of TA/Cu(110) is initiated by a slow, irreversible process that forms vacancies in the adsorbed TA layer, followed by a vacancy-mediated, explosive decomposition process that yields CO{sub 2} and small hydrocarbon products. Initiation of the explosive decomposition of TA/Cu(110) has been studied by measurement of the reaction kinetics, time-resolved low energy electron diffraction (LEED), and time-resolved scanning tunneling microscopy (STM). Initiation results in a decrease in the local coverage of TA and a concomitant increase in the areal vacancy concentration. Observations of explosive TA decomposition on the Cu(651)S surface suggest that initiation does not occur at structural defects in the surface, as has been suggested in the past. Once the vacancy concentration reaches a critical value, the explosive, autocatalytic decomposition step dominates the TA decomposition rate. The onset of the explosive decomposition of TA on Cu(110) is accompanied by the extraction of Cu atoms from the surface to form a (±6,7; {-+}2,1) overlayer that is readily observable using LEED and STM. The explosive decomposition step is second-order in vacancy concentration and accelerates with increasing extent of reaction.

  18. Pb-free Sn-Ag-Cu ternary eutectic solder

    DOEpatents

    Anderson, I.E.; Yost, F.G.; Smith, J.F.; Miller, C.M.; Terpstra, R.L.

    1996-06-18

    A Pb-free solder includes a ternary eutectic composition consisting essentially of about 93.6 weight % Sn-about 4.7 weight % Ag-about 1.7 weight % Cu having a eutectic melting temperature of about 217 C and variants of the ternary composition wherein the relative concentrations of Sn, Ag, and Cu deviate from the ternary eutectic composition to provide a controlled melting temperature range (liquid-solid ``mushy`` zone) relative to the eutectic melting temperature (e.g. up to 15 C above the eutectic melting temperature). 5 figs.

  19. Pb-free Sn-Ag-Cu ternary eutectic solder

    DOEpatents

    Anderson, Iver E.; Yost, Frederick G.; Smith, John F.; Miller, Chad M.; Terpstra, Robert L.

    1996-06-18

    A Pb-free solder includes a ternary eutectic composition consisting essentially of about 93.6 weight % Sn-about 4.7 weight % Ag-about 1.7 weight % Cu having a eutectic melting temperature of about 217.degree. C. and variants of the ternary composition wherein the relative concentrations of Sn, Ag, and Cu deviate from the ternary eutectic composition to provide a controlled melting temperature range (liquid-solid "mushy" zone) relative to the eutectic melting temperature (e.g. up to 15.degree. C. above the eutectic melting temperature).

  20. Itinerant magnetism in metallic CuFe2Ge2

    DOE PAGES [OSTI]

    Shanavas, K. V.; Singh, David J.; He, Ruihua

    2015-03-25

    Theoretical calculations are performed to understand the electronic structure and magnetic properties of CuFe2Ge2. The band structure reveals large electron density N(EF) at the Fermi level suggesting a strong itinerant character of magnetism. The Fermi surface is dominated by two dimensional sheet like structures, with potentially strong nesting between them. The magnetic ground state appears to be ferromagnetic along a and antiferromagnetic in other directions. The results show that CuFe2Ge2 is an antiferromagnetic metal, with similarities to the Fe-based superconductors; such as magnetism with substantial itinerant character and coupling between magnetic order and electrons at the Fermi energy.

  1. Effect of Cu concentration on thermoelectric properties of nanostructured

    Office of Scientific and Technical Information (OSTI)

    p-type MgAg0.97-xCuxSb0.99 (Journal Article) | SciTech Connect Journal Article: Effect of Cu concentration on thermoelectric properties of nanostructured p-type MgAg0.97-xCuxSb0.99 Citation Details In-Document Search Title: Effect of Cu concentration on thermoelectric properties of nanostructured p-type MgAg0.97-xCuxSb0.99 Authors: Sui, Jiehe ; Shuai, Jing ; Lan, Yucheng ; Liu, Yuan ; He, Ran ; Wang, Dezhi ; Jie, Qing ; Ren, Zhifeng Publication Date: 2015-04-01 OSTI Identifier: 1250963

  2. How to stabilize highly active Cu+ cations in a mixed-oxide catalyst

    SciTech Connect

    Mudiyanselage, Kumudu; Luo, Si; Kim, Hyun You; Yang, Xiaofang; Baber, Ashleigh E.; Hoffmann, Friedrich M.; Senanayake, Sananayake; Rodriguez, Jose A.; Chen, Jingguang G.; Liu, Ping; Stacchiola, Dario J.

    2015-09-12

    Mixed-metal oxides exhibit novel properties that are not present in their isolated constituent metal oxides and play a significant role in heterogeneous catalysis. In this study, a titanium-copper mixed-oxide (TiCuOx) film has been synthesized on Cu(111) and characterized by complementary experimental and theoretical methods. At sub-monolayer coverages of titanium, a Cu2O-like phase coexists with TiCuOx and TiOx domains. When the mixed-oxide surface is exposed at elevated temperatures (600–650 K) to oxygen, the formation of a well-ordered TiCuOx film occurs. Stepwise oxidation of TiCuOx shows that the formation of the mixed-oxide is faster than that of pure Cu2O. As the Ti coverage increases, Ti-rich islands (TiOx) form. The adsorption of CO has been used to probe the exposed surface sites on the TiOxCuOx system, indicating the existence of a new Cu+ adsorption site that is not present on Cu2O/Cu(111). Adsorption of CO on Cu+ sites of TiCuOx is thermally more stable than on Cu(111), Cu2O/Cu(111) or TiO2(110). The Cu+ sites in TiCuOx domains are stable under both reducing and oxidizing conditions whereas the Cu2O domains present on sub-monolayer loads of Ti can be reduced or oxidized under mild conditions. Furthermore, the results presented here demonstrate novel properties of TiCuOx films, which are not present on Cu(111), Cu2O/Cu(111), or TiO2(110), and highlight the importance of the preparation and characterization of well-defined mixed-metal oxides in order to understand fundamental processes that could guide the design of new materials.

  3. Distinct oxygen hole doping in different layers of Sr₂CuO4-δ/La₂CuO₄ superlattices

    DOE PAGES [OSTI]

    Smadici, S.; Lee, J. C. T.; Rusydi, A.; Logvenov, G.; Bozovic, I.; Abbamonte, P.

    2012-03-28

    X-ray absorption in Sr₂CuO4-δ/La₂CuO₄ (SCO/LCO) superlattices shows a variable occupation with doping of a hole state different from holes doped for x≲xoptimal in bulk La2-xSrxCuO₄ and suggests that this hole state is on apical oxygen atoms and polarized in the a-b plane. Considering the surface reflectivity gives a good qualitative description of the line shapes of resonant soft x-ray scattering. The interference between superlattice and surface reflections was used to distinguish between scatterers in the SCO and the LCO layers, with the two hole states maximized in different layers of the superlattice.

  4. Controlling superconductivity in La2-xSrxCuO4+δ by ozone and...

    Office of Scientific and Technical Information (OSTI)

    Controlling superconductivity in La2-xSrxCuO4+ by ozone and vacuum annealing Citation Details In-Document Search Title: Controlling superconductivity in La2-xSrxCuO4+ by ozone ...

  5. Solid-solution CrCoCuFeNi high-entropy alloy thin films synthesized...

    Office of Scientific and Technical Information (OSTI)

    Solid-solution CrCoCuFeNi high-entropy alloy thin films synthesized by sputter deposition Title: Solid-solution CrCoCuFeNi high-entropy alloy thin films synthesized by sputter ...

  6. High Chalcocite Cu2S: A Solid-Liquid Hybrid Phase (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    High Chalcocite Cu2S: A Solid-Liquid Hybrid Phase Title: High Chalcocite Cu2S: A Solid-Liquid Hybrid Phase Authors: Wang, Lin-Wang Publication Date: 2012-02-24 OSTI Identifier: ...

  7. Deformation behavior of Nb nanowires in TiNiCu shape memory alloy...

    Office of Scientific and Technical Information (OSTI)

    in TiNiCu shape memory alloy matrix This content will become publicly available on August 18, 2016 Title: Deformation behavior of Nb nanowires in TiNiCu shape memory alloy matrix ...

  8. Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system...

    Office of Scientific and Technical Information (OSTI)

    Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system Title: Ti3CrCu4: A possible ... Country of Publication: United States Language: English Word Cloud More Like This Free ...

  9. Broken Symmetry in the Pseudogap State of YBa2Cu3O6+x (Technical...

    Office of Scientific and Technical Information (OSTI)

    Technical Report: Broken Symmetry in the Pseudogap State of YBa2Cu3O6+x Citation Details In-Document Search Title: Broken Symmetry in the Pseudogap State of YBa2Cu3O6+x You are ...

  10. Engineered CuInSexS2-x Quantum Dots for Sensitized Solar Cells...

    Office of Scientific and Technical Information (OSTI)

    Engineered CuInSexS2-x Quantum Dots for Sensitized Solar Cells Citation Details In-Document Search Title: Engineered CuInSexS2-x Quantum Dots for Sensitized Solar Cells Authors: ...

  11. High-power Laser Interaction With Low-density C-Cu Foams (Journal...

    Office of Scientific and Technical Information (OSTI)

    High-power Laser Interaction With Low-density C-Cu Foams Citation Details In-Document Search Title: High-power Laser Interaction With Low-density C-Cu Foams You are accessing a ...

  12. Classification of Lattice Defects in the Kesterite Cu2ZnSnS4...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Classification of Lattice Defects in the Kesterite Cu2ZnSnS4 and Cu2ZnSnSe4 Earth-Abundant Solar Cell Absorbers Citation Details In-Document Search Title: ...

  13. Origin of Novel Diffusions of Cu and Ag in Semiconductors: The...

    Office of Scientific and Technical Information (OSTI)

    Origin of Novel Diffusions of Cu and Ag in Semiconductors: The Case of CdTe Prev Next Title: Origin of Novel Diffusions of Cu and Ag in Semiconductors: The Case of CdTe ...

  14. First-principles study of carbon impurities in CuInSe{sub 2} and CuGaSe{sub 2}, present in non-vacuum synthesis methods

    SciTech Connect

    Bekaert, J. Saniz, R.; Partoens, B.; Lamoen, D.

    2015-01-07

    A first-principles study of the structural and electronic properties of carbon impurities in CuInSe{sub 2} and CuGaSe{sub 2} is presented. Carbon is present in organic molecules in the precursor solutions used in non-vacuum growth methods for CuInSe{sub 2} and CuGaSe{sub 2} based photovoltaic cells. These growth methods make more efficient use of material, time, and energy than traditional vacuum methods. The formation energies of several carbon impurities are calculated using the hybrid HSE06 functional. C{sub Cu} acts as a shallow donor, C{sub In} and interstitial C yield deep donor levels in CuInSe{sub 2}, while in CuGaSe{sub 2} C{sub Ga} and interstitial C act as deep amphoteric defects. So, these defects reduce the majority carrier (hole) concentration in p-type CuInSe{sub 2} and CuGaSe{sub 2} by compensating the acceptor levels. The deep defects are likely to act as recombination centers for the photogenerated charge carriers and are thus detrimental for the performance of the photovoltaic cells. On the other hand, the formation energies of the carbon impurities are high, even under C-rich growth conditions. Thus, few C impurities will form in CuInSe{sub 2} and CuGaSe{sub 2} in thermodynamic equilibrium. However, the deposition of the precursor solution in non-vacuum growth methods presents conditions far from thermodynamic equilibrium. In this case, our calculations show that C impurities formed in non-equilibrium tend to segregate from CuInSe{sub 2} and CuGaSe{sub 2} by approaching thermodynamic equilibrium, e.g., via thorough annealing.

  15. High strength-high conductivity Cu--Fe composites produced by powder compaction/mechanical reduction

    DOEpatents

    Verhoeven, John D.; Spitzig, William A.; Gibson, Edwin D.; Anderson, Iver E.

    1991-08-27

    A particulate mixture of Cu and Fe is compacted and mechanically reduced to form an "in-situ" Cu-Fe composite having high strength and high conductivity. Compaction and mechanical reduction of the particulate mixture are carried out at a temperature and time at temperature selected to avoid dissolution of Fe into the Cu matrix particulates to a harmful extent that substantially degrades the conductivity of the Cu-Fe composite.

  16. High strength-high conductivity Cu-Fe composites produced by powder compaction/mechanical reduction

    DOEpatents

    Verhoeven, J.D.; Spitzig, W.A.; Gibson, E.D.; Anderson, I.E.

    1991-08-27

    A particulate mixture of Cu and Fe is compacted and mechanically reduced to form an ''in-situ'' Cu-Fe composite having high strength and high conductivity. Compaction and mechanical reduction of the particulate mixture are carried out at a temperature and time at temperature selected to avoid dissolution of Fe into the Cu matrix particulates to a harmful extent that substantially degrades the conductivity of the Cu-Fe composite. 5 figures.

  17. Local structure order in Pd??Cu?Si?? liquid

    DOE PAGES [OSTI]

    Yue, G. Q.; Iowa State Univ., Ames, IA; Zhang, Y.; Sun, Y.; Shen, B.; Dong, F.; Wang, Z. Y.; Zhang, R. J.; Zheng, Y. X.; Kramer, M. J.; et al

    2015-02-05

    The short-range order (SRO) in Pd??Cu?Si?? liquid was studied by high energy x-ray diffraction and ab initio molecular dynamics (MD) simulations. The calculated pair correlation functions at different temperatures agree well with the experimental results. The partial pair correlation functions from ab intio MD simulations indicate that Si atoms prefer to be uniformly distributed while Cu atoms tend to aggregate. By performing structure analysis using Honeycutt-Andersen index, Voronoi tessellation, and atomic cluster alignment method, we show that the icosahedron and face-centered cubic SRO increase upon cooling. The dominant SRO is the Pd-centered Pd?Si? motif, namely the structure of which motifmoreis similar to the structure of Pd-centered clusters in the Pd?Si? crystal. The study further confirms the existence of trigonal prism capped with three half-octahedra that is reported as a structural unit in Pd-based amorphous alloys. The majority of Cu-centered clusters are icosahedra, suggesting that the presence of Cu is benefit to promote the glass forming ability.less

  18. Hydrogen isotope trapping in Al-Cu binary alloys

    SciTech Connect

    Chao, Paul; Karnesky, Richard A.

    2016-01-01

    In this study, the trapping mechanisms for hydrogen isotopes in Al–X Cu (0.0 at. % < X < 3.5 at. %) alloys were investigated using thermal desorption spectroscopy (TDS), electrical conductivity, and differential scanning calorimetry. Constant heating rate TDS was used to determine microstructural trap energies and occupancies. In addition to the trapping states in pure Al reported in the literature (interstitial lattice sites, dislocations, and vacancies), a trap site due to Al–Cu intermetallic precipitates is observed. The binding energy of this precipitate trap is (18 ± 3) kJ•mol–1 (0.19 ± 0.03 eV). Typical occupancy of this trap is high; for Al–2.6 at. % Cu (a Cu composition comparable to that in AA2219) charged at 200 °C with 130 MPa D2 for 68 days, there is ca. there is 3.15×10–7 mol D bound to the precipitate trap per mol of Al, accounting for a third of the D in the charged sample.

  19. Hydrogen isotope trapping in Al-Cu binary alloys

    DOE PAGES [OSTI]

    Chao, Paul; Karnesky, Richard A.

    2016-01-01

    In this study, the trapping mechanisms for hydrogen isotopes in Al–X Cu (0.0 at. % < X < 3.5 at. %) alloys were investigated using thermal desorption spectroscopy (TDS), electrical conductivity, and differential scanning calorimetry. Constant heating rate TDS was used to determine microstructural trap energies and occupancies. In addition to the trapping states in pure Al reported in the literature (interstitial lattice sites, dislocations, and vacancies), a trap site due to Al–Cu intermetallic precipitates is observed. The binding energy of this precipitate trap is (18 ± 3) kJ•mol–1 (0.19 ± 0.03 eV). Typical occupancy of this trap is high;more » for Al–2.6 at. % Cu (a Cu composition comparable to that in AA2219) charged at 200 °C with 130 MPa D2 for 68 days, there is ca. there is 3.15×10–7 mol D bound to the precipitate trap per mol of Al, accounting for a third of the D in the charged sample.« less

  20. Effects of annealing on antiwear and antibacteria behaviors of TaN-Cu nanocomposite thin films

    SciTech Connect

    Hsieh, J. H.; Cheng, M. K.; Chang, Y. K.; Li, C.; Chang, C. L.; Liu, P. C.

    2008-07-15

    TaN-Cu nanocomposite films were deposited by reactive cosputtering on Si and tool steel substrates. The films were then annealed using rapid thermal annealing (RTA) at 400 deg. C for 2, 4, and 8 min, respectively, to induce the nucleation and growth of Cu particles in TaN matrix and on film surface. Field emission scanning electron microscopy was applied to characterize Cu nanoparticles emerged on the surface of TaN-Cu thin films. The effects of annealing on the antiwear and antibacterial properties of these films were studied. The results reveal that annealing by RTA can cause Cu nanoparticles to form on the TaN surface. Consequently, the tribological behaviors, as well as the antibacterial behavior may vary depending on particle size, particle distribution, and total exposed Cu amount. For the samples with large Cu particles, the reduction of averaged friction and wear rate is obvious. Apparently, it is due to the smeared Cu particles adhered onto the wear tracks. This Cu layer may act as a solid lubricant. From the antibacterial testing results, it is found that both Cu particle size and total exposed Cu amount are critical in making short-term antibacterial effect. Overall, all the annealed TaN-Cu samples can reach >99% antibacterial efficiency in 24 h, with respect to uncoated Si substrate.

  1. Shock response of He bubbles in single crystal Cu

    SciTech Connect

    Li, B.; Wang, L.; E, J. C.; Luo, S. N.; Ma, H. H.

    2014-12-07

    With large-scale molecular dynamics simulations, we investigate shock response of He nanobubbles in single crystal Cu. For sufficient bubble size or internal pressure, a prismatic dislocation loop may form around a bubble in unshocked Cu. The internal He pressure helps to stabilize the bubble against plastic deformation. However, the prismatic dislocation loops may partially heal but facilitate nucleation of new shear and prismatic dislocation loops. For strong shocks, the internal pressure also impedes internal jetting, while a bubble assists local melting; a high speed jet breaks a He bubble into pieces dispersed among Cu. Near-surface He bubbles may burst and form high velocity ejecta containing atoms and small fragments, while the ejecta velocities do not follow the three-dimensional Maxwell-Boltzmann distributions expected for thermal equilibrium. The biggest fragment size deceases with increasing shock strength. With a decrease in ligament thickness or an increase in He bubble size, the critical shock strength required for bubble bursting decreases, while the velocity range, space extension and average velocity component along the shock direction, increase. Small bubbles are more efficient in mass ejecting. Compared to voids and perfect single crystal Cu, He bubbles have pronounced effects on shock response including bubble/void collapse, Hugoniot elastic limit (HEL), deformation mechanisms, and surface jetting. HEL is the highest for perfect single crystal Cu with the same orientations, followed by He bubbles without pre-existing prismatic dislocation loops, and then voids. Complete void collapse and shear dislocations occur for embedded voids, as opposed to partial collapse, and shear and possibly prismatic dislocations for He bubbles. He bubbles lower the threshhold shock strength for ejecta formation, and increase ejecta velocity and ejected mass.

  2. An in-situ phosphorus source for the synthesis of Cu3P and the subsequent conversion to Cu3PS4 nanoparticle clusters

    DOE PAGES [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 (Cu3P) and copper thiophosphate (Cu3PS4). Herein, we report a one-pot, solution-based synthesis of Cu3P nanocrystals utilizing an in-situ phosphorus source: phosphorus pentasulfide (P2S5) in trioctylphosphine (TOP). By injecting this phosphorus source into a copper solution in oleylamine (OLA), uniform and size controlled Cu3P nanocrystals with a phosphorous-rich surface are synthesized. The subsequent reaction of the Cu3P nanocrystals with decomposing thiourea forms nanoscale Cu3PS4more » particles having p-type conductivity and an effective optical band gap of 2.36 eV.« less

  3. CO sub 2 induced inhibition of the localized corrosion of aluminum, Al-0. 5% Cu, and Al-2% Cu in dilute HF solution

    SciTech Connect

    Scully, J.R. . Dept. of Materials Science); Peebles, D.E. )

    1991-01-01

    This study presents work on corrosion of aluminum, Al-.5% Cu, and Al-2% Cu. Electrochemical tests were performed in dilute HF solutions both with and without CO{sub 2} sparging. It is suggested that CO{sub 2} or its reaction products interact with the passive film so that exposure of Cu in the oxide-solution interface is minimized. CO{sub 2} is investigated as a corrosion inhibitor. 4 refs. (JDL)

  4. Direct Epoxidation of Propylene over Stabilized Cu+ Surface Sites on Ti Modified Cu2O

    SciTech Connect

    Yang, X.; Kattel, S.; Xiong, K.; Mudiyanselage, K.; Rykov, S.; Senanayake, S. D.; Rodriguez, J. A.; Liu, P.; Stacchiola, D. J.; Chen, J. G.

    2015-07-17

    Direct propylene epoxidation by O2 is a challenging reaction because of the strong tendency for complete combustion. Results from the current study demonstrate the feasibility to tune the epoxidation selectivity by generating highly dispersed and stabilized Cu+ active sites in a TiCuOx mixed oxide. The TiCuOx surface anchors the key surface intermediate, oxametallacycle, leading to higher selectivity for epoxidation of propylene.

  5. Influence of Al/CuO reactive multilayer films additives on exploding foil initiator

    SciTech Connect

    Zhou Xiang; Shen Ruiqi; Ye Yinghua; Zhu Peng; Hu Yan; Wu Lizhi

    2011-11-01

    An investigation on the influence of Al/CuO reactive multilayer films (RMFs) additives on exploding foil initiator was performed in this paper. Cu film and Cu/Al/CuO RMFs were produced by using standard microsystem technology and RF magnetron sputtering technology, respectively. Scanning electron microscopy characterization revealed the distinct layer structure of the as-deposited Al/CuO RMFs. Differential scanning calorimetry was employed to ascertain the amount of heat released in the thermite reaction between Al films and CuO films, which was found to be 2024 J/g. Electrical explosion tests showed that 600 V was the most matching voltage for our set of apparatus. The explosion process of two types of films was observed by high speed camera and revealed that compared with Cu film, an extra distinct combustion phenomenon was detected with large numbers of product particles fiercely ejected to a distance of about six millimeters for Cu/Al/CuO RMFs. By using the atomic emission spectroscopy double line technique, the reaction temperature was determined to be about 6000-7000 K and 8000-9000 K for Cu film and Cu/Al/CuO RMFs, respectively. The piezoelectricity of polyvinylidene fluoride film was employed to measure the average velocity of the slapper accelerated by the explosion of the films. The average velocities of the slappers were calculated to be 381 m/s and 326 m/s for Cu film and Cu/Al/CuO RMFs, respectively, and some probable reasons were discussed with a few suggestions put forward for further work.

  6. NO Chemisorption on Cu/SSZ-13: a Comparative Study from Infrared Spectroscopy and DFT Calculations

    SciTech Connect

    Zhang, Renqin; McEwen, Jean-Sabin; Kollar, Marton; Gao, Feng; Wang, Yilin; Szanyi, Janos; Peden, Charles HF

    2014-11-07

    The locations and energies of Cu ions in a Cu/SSZ-13 zeolite catalyst were investigated by density functional theory (DFT) calculations. For 'naked' Cu2+ ions (i.e., Cu2+ ions with no ligands in their coordination spheres other than zeolite lattice oxygen atoms), the more energetically favorable sites are within a 6-membered ring. However, with the presence of various adsorbates, the energy difference between 6- and 8-membered ring locations greatly diminishes. Specifically, Cu2+ ions are substantially stabilized by -OH ligands (as [CuII(OH)]+), making the extra-framework sites in an 8-membered ring energetically more favorable than 6-membered ring sites. Under fully dehydrated high vacuum conditions with different Si/Al and Cu/Al ratios, three chemisorbed NO species coexist upon exposure of NO to Cu/SSZ-13: NO+, Cu2+-NO and Cu+-NO. The relative signal intensities for these bands vary greatly with Si/Al ratios. The vibrational frequency of chemisorbed NO was found to be very sensitive to the location of Cu2+ ions. On the one hand, with the aid from DFT calculations, the nature for these vibrations can be assigned in detail. On the other hand, the relative intensities for various Cu2+-NO species provide a good measure of the nature of Cu2+ ions as functions of Si/Al and Cu/Al ratios and the presence of humidity. These new findings cast doubt on the generally accepted proposal that only Cu2+ ions located in 6-membered rings are catalytically active for NH3-SCR.

  7. Thermochemical and kinetic aspects of the sulfurization of Cu-Sb and Cu-Bi thin films

    SciTech Connect

    Colombara, Diego; Peter, Laurence M.; Rogers, Keith D.; Hutchings, Kyle

    2012-02-15

    CuSbS{sub 2} and Cu{sub 3}BiS{sub 3} are being investigated as part of a search for new absorber materials for photovoltaic devices. Thin films of these chalcogenides were produced by conversion of stacked and co-electroplated metal precursor layers in the presence of elemental sulfur vapour. Ex-situ XRD and SEM/EDS analyses of the processed samples were employed to study the reaction sequence with the aim of achieving compact layer morphologies. A new 'Time-Temperature-Reaction' (TTR) diagram and modified Pilling-Bedworth coefficients have been introduced for the description and interpretation of the reaction kinetics. For equal processing times, the minimum temperature required for CuSbS{sub 2} to appear is substantially lower than for Cu{sub 3}BiS{sub 3}, suggesting that interdiffusion across the interfaces between the binary sulfides is a key step in the formation of the ternary compounds. The effects of the heating rate and sulfur partial pressure on the phase evolution as well as the potential losses of Sb and Bi during the processes have been investigated experimentally and the results related to the equilibrium pressure diagrams obtained via thermochemical computation. - Graphical Abstract: Example of 3D plot showing the equilibrium pressure surfaces of species potentially escaping from chalcogenide films as a function of temperature and sulfur partial pressure. Bi{sub (g)}, Bi{sub 2(g)}, and BiS{sub (g)} are the gaseous species in equilibrium with solid Bi{sub 2}S{sub 3(s)} considered in this specific example. The pressure threshold plane corresponds to the pressure limit above which the elemental losses from 1 {mu}m thick films exceeds 10% of the original content per cm{sup 2} area of film and dm{sup 3} capacity of sulfurization furnace under static atmosphere conditions. The sulfurization temperature/sulfur partial pressure boundaries required to minimise the elemental losses below a given value can be easily read from the 2D projection of the

  8. Contrasting the Material Chemistry of Cu 2 ZnSnSe 4 and Cu 2 ZnSnS (4- x )

    Office of Scientific and Technical Information (OSTI)

    Se x (Journal Article) | SciTech Connect Contrasting the Material Chemistry of Cu 2 ZnSnSe 4 and Cu 2 ZnSnS (4- x ) Se x Citation Details In-Document Search Title: Contrasting the Material Chemistry of Cu 2 ZnSnSe 4 and Cu 2 ZnSnS (4- x ) Se x Authors: Aguiar, Jeffery A. [1] ; Patel, Maulik [2] ; Aoki, Toshihiro [3] ; Wozny, Sarah [4] ; Al-Jassim, Mowafak [1] + Show Author Affiliations National Renewable Energy Laboratory, Golden CO 80401 USA Department of Materials Science and Engineering,

  9. Methods for producing Cu-67 radioisotope with use of a ceramic capsule for medical applications

    DOEpatents

    Ehst, David A.; Willit, James L.

    2016-04-12

    The present invention provides a method for producing Cu67 radioisotope suitable for use in medical applications. The method comprises irradiating a metallic zinc-68 (Zn68) target within a sealed ceramic capsule with a high energy gamma ray beam. After irradiation, the Cu67 is isolated from the Zn68 by any suitable method (e.g. chemical and or physical separation). In a preferred embodiment, the Cu67 is isolated by sublimation of the zinc in a ceramic sublimation tube to afford a copper residue containing Cu67. The Cu67 can be further purified by chemical means.

  10. Long-term leaching test of incinerator bottom ash: Evaluation of Cu partition

    SciTech Connect

    Lin, Cheng-Fang Wu, Chung-Hsin; Liu, Yen-Chiun

    2007-07-01

    Two types of leaching tests were performed on the bottom ash from municipal solid waste incinerators. A short-term batch test specified by the America Nuclear Society (ANS) and long-term column tests with acetic acid (pH 5.2) as leaching solution were used to evaluate copper leachability. The Cu leaching after the 5-d ANS test is about 1% of the original Cu content of 5300 mg/kg. Upon addition of a stabilizing agent, the Cu leaching quantity is reduced; the extent of reduction depends on the type of chemical used (phosphate, carbonate and sulfide). The 1.6% Na{sub 2}S addition showed negligible Cu leaching, and Na{sub 2}S was, therefore, used in subsequent column tests. The 30-d column test indicates a steady increase of Cu leaching amount with time and reaches about 1.5% of the original Cu content after 30 d. A 180-d column test further increased the Cu leaching to about 5.1% of the original Cu content, whereas no appreciable Cu leaching was found with the addition of 1.6% Na{sub 2}S. A sequential extraction was conducted on the raw ash, ash with the addition of Na{sub 2}S and the residue ash after 30 d of operation to characterize Cu affinity for different solid fractions. The data were used to evaluate the fate of Cu through these interactions.

  11. Effect of CNTs dispersion on the thermal and mechanical properties of Cu/CNTs nanocomposites

    SciTech Connect

    Muhsan, Ali Samer E-mail: faizahmad@petronas.com.my; Ahmad, Faiz E-mail: faizahmad@petronas.com.my; Yusoff, Puteri Sri Melor Megat Bt; Mohamed, Norani M.; Raza, M. Rafi

    2014-10-24

    Modified technique of metal injection molding (MIM) was used to fabricate multiwalled carbon nanotube (CNT) reinforced Cu nanocomposites. The effect of adding different amount of CNTs (0-10 vol.%) on the thermal and mechanical behaviour of the fabricated nanocomposites is presented. Scanning electron microscope analysis revealed homogenous dispersion of CNTs in Cu matrices at different CNTs contents. The experimentally measured thermal conductivities of Cu/CNTs nanocomposites showed extraordinary increase (76% higher than pure sintered Cu) with addition of 10 vol.% CNTs. As compared to the pure sintered Cu, increase in modulus of elasticity (Young's modulus) of Cu/CNTs nanocomposites sintered at 1050°C for 2.5 h was measured to be 48%. However, in case of 7.5 vol.% CNTs, Young's modulus was increased significantly about 51% compared to that of pure sintered Cu.

  12. Utility of reactively sputtered CuN{sub x} films in spintronics devices

    SciTech Connect

    Fang Yeyu; Persson, J.; Zha, C.; Willman, J.; Miller, Casey W.; Aakerman, Johan

    2012-04-01

    We have studied nitrified copper (CuN{sub x}) thin films grown by reactive sputtering in the context of spintronic devices. The Ar-to-N{sub 2} flow ratio enables tunability of the electrical resistivity and surface roughness of the CuN{sub x} films, with the former increasing to nearly 20 times that of Cu, and the latter reduced to the atomic scale. Incorporating this into a Ta/CuN{sub x}/Ta seed stack for spin valves improves the current-in-plane (CIP) magnetoresistance; maximum magnetoresistance results with CuN{sub x} seed layer and Cu interlayer. Finally, finite element modeling results are presented that suggest the use of CuN{sub x} in nanocontact spin torque oscillators can enhance current densities by limiting the current spread through the device. This may positively impact threshold currents, power requirements, and device reliability.

  13. Comparative Study of the Defect Point Physics and Luminescence of the Kesterites Cu2ZnSnS4 and Cu2ZnSnSe4 and Chalcopyrite Cu(In,Ga)Se2: Preprint

    SciTech Connect

    Romero, M. J.; Repins, I.; Teeter, G.; Contreras, M.; Al-Jassim, M.; Noufi, R.

    2012-08-01

    In this contribution, we present a comparative study of the luminescence of the kesterites Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe) and their related chalcopyrite Cu(In,Ga)Se2 (CIGSe). Luminescence spectroscopy suggests that the electronic properties of Zn-rich, Cu-poor kesterites (both CZTS and CZTSe) and Cu-poor CIGSe are dictated by fluctuations of the electrostatic and chemical potentials. The large redshift in the luminescence of grain boundaries in CIGSe, associated with the formation of a neutral barrier is clearly observed in CZTSe, and, to some extent, in CZTS. Kesterites can therefore replicate the fundamental electronic properties of CIGSe.

  14. Solidification behavior and structure of Al-Cu alloy welds

    SciTech Connect

    Brooks, J.A.; Li, M.; Yang, N.C.Y.

    1997-09-01

    The microsegregation behavior of electron beam (EB) and gas tungsten arc (GTA) welds of Al-Cu alloys covering a range from 0.19 to 7.74 wt% Cu were characterized for dendrite core concentrations and fraction eutectic solidification. Although a single weld speed of 12.7 mm/sec was used, some differences were observed in the segregation behavior of the two weld types. The microsegregation behavior was also modeled using a finite differences technique considering dendrite tip and eutectic undercooling and solid state diffusion. Fairly good agreement was observed between measured and calculated segregation behavior although differences between the two weld types could not be completely accounted for. The concept of dendrite tip undercooling was used to explain the formation of a single through thickness centerline grain in the higher alloy content GTA welds.

  15. Intermixing in Cu/Ni multilayers induced by cold rolling

    SciTech Connect

    Wang, Z.; Perepezko, J. H.; Larson, D.; Reinhard, D.

    2015-04-28

    Repeated cold rolling was performed on multilayers of Cu60/Ni40 and Cu40/Ni60 foil arrays to study the details of driven atomic scale interfacial mixing. With increasing deformation, there is a significant layer refinement down to the nm level that leads to the formation of a solid solution phase from the elemental end members. Intriguingly, the composition of the solid solution is revealed by an oscillation in the composition profile across the multilayers, which is different from the smoothly varying profile due to thermally activated diffusion. During the reaction, Cu mixed into Ni preferentially compared to Ni mixing into Cu, which is also in contrast to the thermal diffusion behavior. This is confirmed by observations from X-ray diffraction, electron energy loss spectrum and atom probe tomography. The diffusion coefficient induced by cold rolling is estimated as 1.7 × 10{sup −17} m{sup 2}/s, which cannot be attributed to any thermal effect. The effective temperature due to the deformation induced mixing is estimated as 1093 K and an intrinsic diffusivity d{sub b}, which quantifies the tendency towards equilibrium in the absence of thermal diffusion, is estimated as 6.38 × 10{sup −18} m{sup 2}/s. The fraction of the solid solution phase formed is illustrated by examining the layer thickness distribution and is described by using an error function representation. The evolution of mixing in the solid solution phase is described by a simplified sinusoid model, in which the amplitude decays with increased deformation level. The promoted diffusion coefficient could be related to the effective temperature concept, but the establishment of an oscillation in the composition profile is a characteristic behavior that develops due to deformation.

  16. Impedance analysis of MnCoCuO NTC ceramic

    SciTech Connect

    Song, S.G. . E-mail: song-ph0@wpmail.paisley.ac.uk; Ling, Z.; Placido, F.

    2005-07-12

    Impedance spectroscopy is often used to analyse the electrical properties of ceramic materials having high-resistive grain boundaries, such as ZnO and SrTiO{sub 3}. Fewer attempts have been made at using this technique for the analysis of inhomogeneous electronic ceramics consisting of grains with differing composition, such as those occurring in negative temperature coefficient (NTC) thermistors. In this study, we have attempted to adopt ac impedance spectroscopy together with other techniques to analyse an NTC thermistor ceramic material. An Mn, Co and Cu multielements transition metal oxide (MnCoCuO) ceramic was prepared by using homogeneous precipitation employing oxalic acid. This material displayed a typical NTC effect, showing an electrical resistance decrease with temperature when dc electrical measurement was performed. The ac impedance spectroscopy analysis showed that there were two peaks in impedance and conductance versus frequency plot. By using an alternative representation of impedance spectra Z'/f versus Z', three distinct relaxation frequency ranges were identified. They are believed to originate, respectively, from the electrode, phase 1 (rich-Cu phase) and phase 2 (poor-Cu phase) grains existing in this ceramic. SEM observation and EDX analysis clearly showed existence of two distinct phase grains. The resistance values were derived from phases 1 and 2 grains based on ac impedance data. The sum of the resistance values was in good agreement with that from dc measurement in the temperature range of 30-95 deg. C. The material constant, B, for the two phases was also calculated, giving 3100 and 3600 K for phases 1 and 2, respectively.

  17. CuC1 thermochemical cycle for hydrogen production

    DOEpatents

    Fan, Qinbai; Liu, Renxuan

    2012-01-03

    An electrochemical cell for producing copper having a dense graphite anode electrode and a dense graphite cathode electrode disposed in a CuCl solution. An anion exchange membrane made of poly(ethylene vinyl alcohol) and polyethylenimine cross-linked with a cross-linking agent selected from the group consisting of acetone, formaldehyde, glyoxal, glutaraldehyde, and mixtures thereof is disposed between the two electrodes.

  18. Synthesis of BiPbSrCaCuO superconductor

    DOEpatents

    Hults, W.L.; Kubat-Martin, K.A.; Salazar, K.V.; Phillips, D.S.; Peterson, D.E.

    1994-04-05

    A process and a precursor composition for preparing a lead-doped bismuth-strontium-calcium-copper oxide superconductor of the formula Bi[sub a]Pb[sub b]Sr[sub c]Ca[sub d]Cu[sub e]O[sub f] wherein a is from about 1.7 to about 1.9, b is from about 0.3 to about 0.45, c is from about 1.6 to about 2.2, d is from about 1.6 to about 2.2, e is from about 2.97 to about 3.2 and f is 10[+-]z by reacting a mixture of Bi[sub 4]Sr[sub 3]Ca[sub 3]Cu[sub 4]O[sub 16[+-]z], an alkaline earth metal cuprate, e.g., Sr[sub 9]Ca[sub 5]Cu[sub 24]O[sub 41], and an alkaline earth metal plumbate, e.g., Ca[sub 2[minus]x]Sr[sub x]PbO[sub 4] wherein x is about 0.5, is disclosed.

  19. Synthesis of BiPbSrCaCuO superconductor

    DOEpatents

    Hults, William L.; Kubat-Martin, Kimberly A.; Salazar, Kenneth V.; Phillips, David S.; Peterson, Dean E.

    1994-01-01

    A process and a precursor composition for preparing a lead-doped bismuth-strontium-calcium-copper oxide superconductor of the formula Bi.sub.a Pb.sub.b Sr.sub.c Ca.sub.d Cu.sub.e O.sub.f wherein a is from about 1.7 to about 1.9, b is from about 0.3 to about 0.45, c is from about 1.6 to about 2.2, d is from about 1.6 to about 2.2, e is from about 2.97 to about 3.2 and f is 10.+-.z by reacting a mixture of Bi.sub.4 Sr.sub.3 Ca.sub.3 Cu.sub.4 O.sub.16.+-.z, an alkaline earth metal cuprate, e.g., Sr.sub.9 Ca.sub.5 Cu.sub.24 O.sub.41, and an alkaline earth metal plumbate, e.g., Ca.sub.2-x Sr.sub.x PbO.sub.4 wherein x is about 0.5, is disclosed.

  20. Effects of Cu Diffusion from ZnTe:Cu/Ti Contacts on Carrier Lifetime of CdS/CdTe Thin Film Solar Cells: Preprint

    SciTech Connect

    Gessert, T. A.; Metzger, W. K.; Asher, S. E.; Young, M. R.; Johnston, S.; Dhere, R. G.; Duda, A.

    2008-05-01

    We study the performance of CdS/CdTe thin film PV devices processed with a ZnTe:Cu/Ti contact to investigate how carrier lifetime in the CdTe layer is affected by Cu diffusion from the contact.

  1. Submillimeter and microwave residual losses in epitaxial films of Y-Ba-Cu-O and Tl-Ca-Ba-Cu-O

    SciTech Connect

    Miller, D.; Richards, P.L.; Garrison, S.M.; Newman, N.; Eom, C.B.; Geballe, T.H.; Etemad, S.; Inam, A.; Venkatesan, T.; Martens, J.S.; Lee, W.Y.; Bourne, L.C.

    1992-03-01

    We have used a novel bolometric technique and a resonant technique to obtain accurate submillimeter and microwave residual loss data for epitaxial thin films of YBa{sub 2}Cu{sub 3}O{sub 7}, Tl{sub 2}Ca{sub 2}Ba{sub 2}Cu{sub 3}O{sub 10} and Tl{sub 2}CaBa{sub 2}Cu{sub 2}O{sub 8}. For all films we obtain good agreement between the submillimeter and microwave data, with the residual losses in both the Y-Ba-Cu-O and Tl-Ca-Ba-Cu-O films scaling approximately as frequency squared below {approximately} 1 THz. We are able to fit the losses in the Y-Ba-Cu-O films to a weakly coupled grain model for the a-b plane conductivity, in good agreement with results from a Kramers-Kronig analysis of the loss data. We observe strong phonon structure in the Tl-Ca-Ba-Cu-O films for frequencies between 2 and 21 THz, and are unable to fit these losses to the simple weakly coupled grain model. This is in strong contrast to the case for other high {Tc} superconductors such as YBa{sub 2}Cu{sub 3}O{sub 7}, where phonon structure observed in ceramic samples is absent in epitaxial oriented films and crystals because of the electronic screening due to the high conductivity of the a-b planes.

  2. Complex catalytic behaviors of CuTiOx mixed-oxide during CO oxidation

    DOE PAGES [OSTI]

    Kim, Hyun You; Liu, Ping

    2015-09-21

    Mixed metal oxides have attracted considerable attention in heterogeneous catalysis due to the unique stability, reactivity, and selectivity. Here, the activity and stability of the CuTiOx monolayer film supported on Cu(111), CuTiOx/Cu(111), during CO oxidation was explored using density functional theory (DFT). The unique structural frame of CuTiOx is able to stabilize and isolate a single Cu+ site on the terrace, which is previously proposed active for CO oxidation. Furthermore, it is not the case, where the reaction via both the Langmuir–Hinshelwood (LH) and the Mars-van Krevelen (M-vK) mechanisms are hindered on such single Cu+ site. Upon the formation ofmore » step-edges, the synergy among Cuδ+ sites, TiOx matrix, and Cu(111) is able to catalyze the reaction well. Depending on temperatures and partial pressure of CO and O2, the surface structure varies, which determines the dominant mechanism. In accordance with our results, the Cuδ+ ion alone does not work well for CO oxidation in the form of single sites, while the synergy among multiple active sites is necessary to facilitate the reaction.« less

  3. Study of Cu and Pb partitioning in mine tailings using the Tessier sequential extraction scheme

    SciTech Connect

    Andrei, Mariana Lucia; Senila, Marin; Hoaghia, Maria Alexandra; Levei, Erika-Andrea; Borodi, Gheorghe

    2015-12-23

    The Cu and Pb partitioning in nonferrous mine tailings was investigated using the Tessier sequential extraction scheme. The contents of Cu and Pb found in the five operationally defined fractions were determined by inductively coupled plasma optical emission spectrometry. The results showed different partitioning patterns for Cu and Pb in the studied tailings. The total Cu and Pb contents were higher in tailings from Brazesti than in those from Saliste, while the Cu contents in the first two fractions considered as mobile were comparable and the content of mobile Pb was the highest in Brazesti tailings. In the tailings from Saliste about 30% of Cu and 3% of Pb were found in exchangeable fraction, while in those from Brazesti no metals were found in the exchangeable fraction, but the percent of Cu and Pb found in the bound to carbonate fraction were high (20% and 26%, respectively). The highest Pb content was found in the residual fraction in Saliste tailings and in bound to Fe and Mn oxides fraction in Brazesti tailings, while the highest Cu content was found in the fraction bound to organic matter in Saliste tailings and in the residual fraction in Brazesti tailings. In case of tailings of Brazesti medium environmental risk was found both for Pb and Cu, while in case of Saliste tailings low risk for Pb and high risk for Cu were found.

  4. Systematic study of azimuthal anisotropy in Cu + Cu and Au + Au collisions at √sNN = 62.4 and 200 GeV

    DOE PAGES [OSTI]

    Adare, A.

    2015-09-23

    We have studied the dependence of azimuthal anisotropy v2 for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of v2 as a function of transverse momentum pT and centrality in Au+Au collisions at √sNN=200 and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in v2 values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that v2 depends both on eccentricity and themore » number of participants, Npart. We observe that v2 divided by eccentricity (ε) monotonically increases with Npart and scales as N1/3part. Thus, the Cu+Cu data at 62.4 GeV falls below the other scaled v2 data. For identified hadrons, v2 divided by the number of constituent quarks nq is independent of hadron species as a function of transverse kinetic energy KET=mT–m between 0.1T/nq<1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of v2/(nq∙ε∙N1/3part) vs KET/nq for all measured particles.« less

  5. Systematic study of azimuthal anisotropy in Cu + Cu and Au + Au collisions at √sNN = 62.4 and 200 GeV

    SciTech Connect

    Adare, A.

    2015-09-23

    We have studied the dependence of azimuthal anisotropy v2 for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of v2 as a function of transverse momentum pT and centrality in Au+Au collisions at √sNN=200 and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in v2 values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that v2 depends both on eccentricity and the number of participants, Npart. We observe that v2 divided by eccentricity (ε) monotonically increases with Npart and scales as N1/3part. Thus, the Cu+Cu data at 62.4 GeV falls below the other scaled v2 data. For identified hadrons, v2 divided by the number of constituent quarks nq is independent of hadron species as a function of transverse kinetic energy KET=mT–m between 0.1T/nq<1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of v2/(nq∙ε∙N1/3part) vs KET/nq for all measured particles.

  6. Oxygen-induced Y surface segregation in a CuPdY ternary alloy

    SciTech Connect

    Tafen, D. N.; Miller, J. B.; Dogan, O. N.; Baltrus, J. P.; Kondratyuk, P.

    2013-01-01

    We present a comprehensive theoretical and experimental study of the segregation behavior of the ternary alloy CuPdY in vacuum (i.e., the clean surface) and in the presence of oxygen. Theoretical prediction shows that for clean surface, yttrium will substitute first for Cu and then for Pd at the subsurface lattice site before segregating to the surface where it substitutes for Cu. XRD characterization of the surface of CuPdY indicates the presence of two major phases, B2 CuPd and Pd{sub 3}Y. In the presence of adsorbed oxygen, theory predicts that Y preferentially occupies surface sites due to its stronger oxygen affinity compared to Cu and Pd. XPS experiments confirm the computational results in the adsorbed oxygen case, showing that surface segregation of yttrium is induced by the formation of Y-oxides at the top-surface of the alloy.

  7. Fe and Co nanostructures embedded into the Cu(100) surface: Self-Organization and magnetic properties

    SciTech Connect

    Kolesnikov, S. V. Klavsyuk, A. L.; Saletsky, A. M.

    2015-10-15

    The self-organization and magnetic properties of small iron and cobalt nanostructures embedded into the first layer of a Cu(100) surface are investigated using the self-learning kinetic Monte Carlo method and density functional theory. The similarities and differences between the Fe/Cu(100) and the Co/Cu(100) are underlined. The time evolution of magnetic properties of a copper monolayer with embedded magnetic atoms at 380 K is discussed.

  8. Adsorbate-driven morphological changes on Cu(111) nano-pits

    SciTech Connect

    Mudiyanselage, K.; Xu, F.; Hoffmann, F. M.; Hrbek, J.; Waluyo, I.; Boscoboinik, J. A.; Stacchiola, D. J.

    2014-12-09

    Adsorbate-driven morphological changes of pitted-Cu(111) surfaces have been investigated following the adsorption and desorption of CO and H. The morphology of the pitted-Cu(111) surfaces, prepared by Ar+ sputtering, exposed a few atomic layers deep nested hexagonal pits of diameters from 8 to 38 nm with steep step bundles. The roughness of pitted-Cu(111) surfaces can be healed by heating to 450-500 K in vacuum. Adsorption of CO on the pitted-Cu(111) surface leads to two infrared peaks at 2089-2090 and 2101-2105 cm-1 for CO adsorbed on under-coordinated sites in addition to the peak at 2071 cm-1 for CO adsorbed on atop sites of the close-packed Cu(111) surface. CO adsorbed on under-coordinated sites is thermally more stable than that of atop Cu(111) sites. Annealing of the CO-covered surface from 100 to 300 K leads to minor changes of the surface morphology. In contrast, annealing of a H covered surface to 300 K creates a smooth Cu(111) surface as deduced from infrared data of adsorbed CO and scanning tunnelling microscopy (STM) imaging. The observation of significant adsorbate-driven morphological changes with H is attributed to its stronger modification of the Cu(111) surface by the formation of a sub-surface hydride with a hexagonal structure, which relaxes into the healed Cu(111) surface upon hydrogen desorption. These morphological changes occur ~150 K below the temperature required for healing of the pitted-Cu(111) surface by annealing in vacuum. In contrast, the adsorption of CO, which only interacts with the top-most Cu layer and desorbs by 160 K, does not significantly change the morphology of the pitted-Cu(111) surface.

  9. Adsorbate-driven morphological changes on Cu(111) nano-pits

    DOE PAGES [OSTI]

    Mudiyanselage, K.; Xu, F.; Hoffmann, F. M.; Hrbek, J.; Waluyo, I.; Boscoboinik, J. A.; Stacchiola, D. J.

    2014-12-09

    Adsorbate-driven morphological changes of pitted-Cu(111) surfaces have been investigated following the adsorption and desorption of CO and H. The morphology of the pitted-Cu(111) surfaces, prepared by Ar+ sputtering, exposed a few atomic layers deep nested hexagonal pits of diameters from 8 to 38 nm with steep step bundles. The roughness of pitted-Cu(111) surfaces can be healed by heating to 450-500 K in vacuum. Adsorption of CO on the pitted-Cu(111) surface leads to two infrared peaks at 2089-2090 and 2101-2105 cm-1 for CO adsorbed on under-coordinated sites in addition to the peak at 2071 cm-1 for CO adsorbed on atop sitesmore » of the close-packed Cu(111) surface. CO adsorbed on under-coordinated sites is thermally more stable than that of atop Cu(111) sites. Annealing of the CO-covered surface from 100 to 300 K leads to minor changes of the surface morphology. In contrast, annealing of a H covered surface to 300 K creates a smooth Cu(111) surface as deduced from infrared data of adsorbed CO and scanning tunnelling microscopy (STM) imaging. The observation of significant adsorbate-driven morphological changes with H is attributed to its stronger modification of the Cu(111) surface by the formation of a sub-surface hydride with a hexagonal structure, which relaxes into the healed Cu(111) surface upon hydrogen desorption. These morphological changes occur ~150 K below the temperature required for healing of the pitted-Cu(111) surface by annealing in vacuum. In contrast, the adsorption of CO, which only interacts with the top-most Cu layer and desorbs by 160 K, does not significantly change the morphology of the pitted-Cu(111) surface.« less

  10. Adsorbate-driven morphological changes on Cu(111) nano-pits

    SciTech Connect

    Mudiyanselage, K.; Xu, F.; Hoffmann, F. M.; Hrbek, J.; Waluyo, I.; Boscoboinik, J. A.; Stacchiola, D. J.

    2015-01-01

    Adsorbate-driven morphological changes of pitted-Cu(111) surfaces have been investigated following the adsorption and desorption of CO and H. The morphology of the pitted-Cu(111) surfaces, prepared by Ar+ sputtering, exposed a few atomic layers deep nested hexagonal pits of diameters from 8 to 38 nm with steep step bundles. The roughness of pitted-Cu(111) surfaces can be healed by heating to 450-500 K in vacuum. Adsorption of CO on the pitted-Cu(111) surface leads to two infrared peaks at 2089-2090 and 2101-2105 cm-1 for CO adsorbed on under-coordinated sites in addition to the peak at 2071 cm-1 for CO adsorbed on atop sites of the close-packed Cu(111) surface. CO adsorbed on under-coordinated sites is thermally more stable than that of atop Cu(111) sites. Annealing of the CO-covered surface from 100 to 300 K leads to minor changes of the surface morphology. In contrast, annealing of a H covered surface to 300 K creates a smooth Cu(111) surface as deduced from infrared data of adsorbed CO and scanning tunnelling microscopy (STM) imaging. The observation of significant adsorbate-driven morphological changes with H is attributed to its stronger modification of the Cu(111) surface by the formation of a sub-surface hydride with a hexagonal structure, which relaxes into the healed Cu(111) surface upon hydrogen desorption. These morphological changes occur ~150 K below the temperature required for healing of the pitted-Cu(111) surface by annealing in vacuum. In contrast, the adsorption of CO, which only interacts with the top-most Cu layer and desorbs by 160 K, does not significantly change the morphology of the pitted-Cu(111) surface.

  11. Surface segregation as a means of gettering Cu in liquid-phase-epitaxy silicon thin layers grown from Al-Cu-Si solutions

    SciTech Connect

    Wang, T.H.; Ciszek, T.F.; Reedy, R.; Asher, S.; King, D.

    1996-05-01

    The authors demonstrate that, by using the natural surface segregation phenomenon, Cu can be gettered to the surface from the bulk of silicon layers so that its concentrations in the liquid-phase-epitaxy (LPE) layers are much lower than its solubility at the layer growth temperature and the reported 10{sup 17} cm{sup {minus}3} degradation threshold for solar-cell performance. Secondary-ion mass spectroscopy (SIMS) analysis indicates that, within a micron-deep sub-surface region, Cu accumulates even in as-grown LPE samples. Slower cooling after growth to room temperature enhances this Cu enrichment. X-ray photoelectron spectroscopy (XPS) measurement shows as much as 3.2% Cu in a surface region of about 50 {Angstrom}. More surface-sensitive, ion-scattering spectroscopy (ISS) analysis further reveals about 7% of Cu at the top surface. These results translate to an areal gettering capacity of about 1.0 x 10{sup 16} cm{sup {minus}2}, which is higher than the available total-area density of Cu in the layer and substrate (3.6 x 10{sup 15} cm{sup {minus}2} for a uniform 1.2 x 10{sup 17}cm{sup {minus}3} Cu throughout the layer and substrate with a total thickness of 300 {mu}m).

  12. Method of fabricating high-efficiency Cu(In,Ga)(Se,S){sub 2} thin films for solar cells

    DOEpatents

    Noufi, R.; Gabor, A.M.; Tuttle, J.R.; Tennant, A.L.; Contreras, M.A.; Albin, D.S.; Carapella, J.J.

    1995-08-15

    A process for producing a slightly Cu-poor thin film of Cu(In,Ga)(Se,S){sub 2} comprises depositing a first layer of (In,Ga){sub x} (Se,S){sub y} followed by depositing just enough Cu+(Se,S) or Cu{sub x} (Se,S) to produce the desired slightly Cu-poor material. In a variation, most, but not all, (about 90 to 99%) of the (In,Ga){sub x} (Se,S){sub y} is deposited first, followed by deposition of all the Cu+(Se,S) or Cu{sub x} (Se,S) to go near stoichiometric, possibly or even preferably slightly Cu-rich, and then in turn followed by deposition of the remainder (about 1 to 10%) of the (In,Ga){sub x} (Se,S){sub y} to end with a slightly Cu-poor composition. In yet another variation, a small portion (about 1 to 10%) of the (In,Ga){sub x} (Se,S){sub y} is first deposited as a seed layer, followed by deposition of all of the Cu+(Se,S) or Cu{sub x} (Se,S) to make a very Cu-rich mixture, and then followed deposition of the remainder of the (In,Ga){sub x} (Se,S){sub y} to go slightly Cu-poor in the final Cu(In,Ga)(Se,S){sub 2} thin film. 5 figs.

  13. Method of fabricating high-efficiency Cu(In,Ga)(SeS).sub.2 thin films for solar cells

    DOEpatents

    Noufi, Rommel; Gabor, Andrew M.; Tuttle, John R.; Tennant, Andrew L.; Contreras, Miguel A.; Albin, David S.; Carapella, Jeffrey J.

    1995-01-01

    A process for producing a slightly Cu-poor thin film of Cu(In,Ga)(Se,S).sub.2 comprises depositing a first layer of (In,Ga).sub.x (Se,S).sub.y followed by depositing just enough Cu+(Se,S) or Cu.sub.x (Se,S) to produce the desired slightly Cu-poor material. In a variation, most, but not all, (about 90 to 99%) of the (In,Ga).sub.x (Se,S).sub.y is deposited first, followed by deposition of all the Cu+(Se,S) or Cu.sub.x (Se,S) to go near stoichiometric, possibly or even preferably slightly Cu-rich, and then in turn followed by deposition of the remainder (about 1 to 10%) of the (In,Ga).sub.x (Se,S).sub.y to end with a slightly Cu-poor composition. In yet another variation, a small portion (about 1 to 10%) of the (In,Ga).sub.x (Se,S).sub.y is first deposited as a seed layer, followed by deposition of all of the Cu+(Se,S) or Cu.sub.x (Se,S) to make a very Cu-rich mixture, and then followed deposition of the remainder of the (In,Ga).sub.x (Se,S).sub.y to go slightly Cu-poor in the final Cu(In,Ga)(Se,S).sub.2 thin film.

  14. Controlling superconductivity in La2-xSrxCuO4+δ by ozone and...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Controlling superconductivity in La2-xSrxCuO4+ by ozone and vacuum annealing Citation Details In-Document Search Title: Controlling superconductivity in ...

  15. Method of forming superconducting Tl-Ba-Ca-Cu-O films

    DOEpatents

    Wessels, Bruce W.; Marks, Tobin J.; Richeson, Darrin S.; Tonge, Lauren M.; Zhang, Jiming

    1993-01-01

    A method of forming a superconducting Tl-Ba-Ca-Cu-O film is disclosed, which comprises depositing a Ba-Ca-Cu-O film on a substrate by MOCVD, annealing the deposited film and heat-treating the annealed film in a closed circular vessel with TlBa.sub.2 Ca.sub.2 Cu.sub.3 O.sub.x and cooling to form said superconducting film of TlO.sub.m Ba.sub.2 Ca.sub.n-1 Cu.sub.n O.sub.2n+2, wherein m=1,2 and n=1,2,3.

  16. Phase Diagram of CuCrO2 in a Magnetic Field

    SciTech Connect

    Fishman, Randy Scott

    2011-01-01

    The magnetic phase diagram of CuCrO2 is constructed as a function of magnetic field and anisotropy using a trial spin state built from harmonics of a fundamental ordering wavevector. Whereas the multiferroic phase of CuCrO2 is a modified spin spiral with a 3-sublattice (SL) period, the phase diagram also contains 1-SL, 2-SL, 4-SL, and 5-SL collinear states which may be accessi- ble in the nonstoichiometric compound CuCrO2+ . For small anisotropy, CuCrO2 is predicted to undergo a transition between two modified spiral states with an intervening 3-SL collinear phase.

  17. Mitigation of the Impact of Pt Contamination on Cu-Zeolite SCR...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Mitigation of the Impact of Pt Contamination on Cu-Zeolite SCR Catalyst Performance Investigates operating conditions under which PGM elements get volatilized and transferred onto ...

  18. Electrical properties of single CuO nanowires for device fabrication: Diodes and field effect transistors

    SciTech Connect

    Florica, Camelia; Costas, Andreea; Boni, Andra Georgia; Negrea, Raluca; Preda, Nicoleta E-mail: encu@infim.ro; Pintilie, Lucian; Enculescu, Ionut E-mail: encu@infim.ro; Ion, Lucian

    2015-06-01

    High aspect ratio CuO nanowires are synthesized by a simple and scalable method, thermal oxidation in air. The structural, morphological, optical, and electrical properties of the semiconducting nanowires were studied. Au-Ti/CuO nanowire and Pt/CuO nanowire electrical contacts were investigated. A dominant Schottky mechanism was evidenced in the Au-Ti/CuO nanowire junction and an ohmic behavior was observed for the Pt/CuO nanowire junction. The Pt/CuO nanowire/Pt structure allows the measurements of the intrinsic transport properties of the single CuO nanowires. It was found that an activation mechanism describes the behavior at higher temperatures, while a nearest neighbor hopping transport mechanism is characteristic at low temperatures. This was also confirmed by four-probe resistivity measurements on the single CuO nanowires. By changing the metal/semiconductor interface, devices such as Schottky diodes and field effect transistors based on single CuO p-type nanowire semiconductor channel are obtained. These devices are suitable for being used in various electronic circuits where their size related properties can be exploited.

  19. Possibility of creating weldable alloys on the basis of the system Al-Cu-Li

    SciTech Connect

    Fridlyander, I.N.; Drits, A.M.; Krymova, T.V.

    1992-03-01

    The weldability of alloys of the system Al-Cu-Li is studied and promising alloying ranges are established for weldable alloys: 5.5-6.5% Cu, 0.8-1.4% Li and 2.5-3.5% Cu, 1.9-2.5% Li. The positive effect of adding small amounts of scandium on the weldability and mechanical properties of alloys of the system Al-Cu-Li is demonstrated. Properties at normal and cryogenic temperatures are given for a new weldable alloy 1460. 7 refs., 6 figs., 2 tabs.

  20. Effects of Cr/Zn Substitutions on Dielectric Properties of CaCu...

    Office of Scientific and Technical Information (OSTI)

    Our results indicate that Cu and Ti sites play an important role in the formation of ... Country of Publication: United States Language: English Subject: 36 MATERIALS SCIENCE; ...

  1. Deactivation Mechanism of Cu/Zeolite SCR Catalyst Due to Reductive Hydrothermal Aging

    Energy.gov [DOE]

    Better control for preventing catalyst deactivation resulted from study of and proposed mechanism for deactivation of Cu/zeolite under rich conditions.

  2. Structural, optical and ethanol sensing properties of Cu-doped SnO{sub 2} nanowires

    SciTech Connect

    Johari, Anima Sharma, Manish; Johari, Anoopshi; Bhatnagar, M. C.

    2014-04-24

    In present work, one-dimensional nanostructure of Cu-doped Tin oxide (SnO{sub 2}) was synthesized by using thermal evaporation method in a tubular furnace under Nitrogen (N{sub 2}) ambience. The growth was carried out at atmospheric pressure. SEM and TEM images reveal the growth of wire-like nanostructures of Cu-doped SnO{sub 2} on Si substrate. The XRD analysis confirms that the synthesized SnO{sub 2} nanowires have tetragonal rutile structure with polycrystalline nature and X-ray diffraction pattern also showed that Cu gets incorporated into the SnO{sub 2} lattice. EDX spectra confirm the doping of Cu into SnO{sub 2} nanowires and atomic fraction of Cu in nanowires is ∼ 0.5 at%. The Vapor Liquid Solid (VLS) growth mechanism for Cu-doped SnO{sub 2} nanowires was also confirmed by EDX spectra. The optical properties of as grown Cu-doped SnO{sub 2} nanowires were studied by using UV-vis spectra which concludes the band gap of about 3.7 eV. As synthesized single Cu-doped SnO{sub 2} nanowire based gas sensor exhibit relatively good performance to ethanol gas. This sensing behaviour offers a suitable application of the Cu-doped SnO{sub 2} nanowire sensor for detection of ethanol gas.

  3. Microstructure and Corrosion Behavior of the Cu-Pd-X Ternary...

    Office of Scientific and Technical Information (OSTI)

    Microstructure and Corrosion Behavior of the Cu-Pd-X Ternary Alloys for Hydrogen Separation Membranes Citation Details In-Document Search Title: Microstructure and Corrosion...

  4. Earth-Abundant Cu-based Chalcogenide Materials as Photovoltaic Absorbers

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Photovoltaic (PV) conversion is demonstrated for the first time in Cu 3 PSe 4 , a member of the Cu 3 MCh 4 (Ch = S,Se; M = P, As, Sb) materials family, identified using the inverse design method as absorber candidates that have stronger solar absorption than CuInSe 2 . Significance and Impact The Cu 3 MCh 4 materials family provides a unique opportunity for addressing needs in single- and multijunction cells for both PV and photo-electrochemical water splitting with a single, inexpensive set of

  5. In-situ surface composition measurements of CuGaSe{sub 2} thin films

    SciTech Connect

    Fons, P.; Yamada, A.; Niki, S.; Oyanagi, H.

    1998-12-31

    Two CuGaSe{sub 2} films were grown by molecular beam epitaxy onto GaAs (001) substrates with varying Cu/Ga flux ratios under Se overpressure conditions. Growth was interrupted at predetermined times and the surface composition was measured using Auger electron spectroscopy after which growth was continued. After growth, the film composition was analyzed using voltage dependent electron microprobe spectroscopy. Film structure and morphology were also analyzed using x-ray diffraction and atomic force microscopy. The film with a Cu/Ga ratio larger than unity showed evidence of surface segregation of a second Cu-rich phase with a Cu/Se composition ratio slightly greater than unity. A second CuGaSe{sub 2} film with a Cu/Ga ratio of less than unity showed no change in surface composition with time and was also consistent with bulk composition measurements. Diffraction measurements indicated a high concentration of twins as well as the presence of domains with mixed c and a axes in the Ga-rich film. The Cu-rich films by contrast were single domain and had a narrower mosaics. High sensitivity scans along the [001] reciprocal axis did not exhibit any new peaks not attributable to either the substrate or the CuGaSe{sub 2} thin film.

  6. Preliminary characterization of interlayer for Be/Cu sintered compacts

    SciTech Connect

    Sakamoto, N.; Kawamura, H.

    1995-09-01

    At present, beryllium is under consideration as a main candidate material for plasma facing components of ITER, because of its many advantages such as low Z, high thermal conductivity, low tritium retention, low activation and so on. Among the different divertor design options, the duplex structure where the beryllium armor is bonded with heat sink structural materials (DS-copper, Cu-Cr-Zr and so on) is under consideration. And plasma facing components will be exposed to high heat load and high neutron flux generated by the plasma. Therefore, it is necessary to develop the reliable bonding technologies between beryllium and heat sink structural materials in order to fabricate plasma facing components which can resist those. Then, we started the bonding technology development of beryllium and copper alloy with FGM (functional gradient material) in order to reduce thermal stress due to the difference of thermal expansion between beryllium and copper alloy. As the interlayers for FGM, eleven kinds of sintered compacts in which the mixing ratio of beryllium powder and oxygen free copper powder is different, were fabricated by the hot press/HIP method. The dimension of each compact is 8mm in diameter, 2mm in thickness. Then, thermal diffusivity and specific heat of these compacts were measured by laser flash method, and thermal conductivity was calculated from those values. From metalographical observation, it became clear that the sintered compacts of mixture of beryllium powder and copper powder contain residual beryllium, copper and two kinds of intermetallic compounds, Be{sub 2}Cu({delta}) and BeCu({gamma}). From the results of thermal characterization, thermal diffusivity of interlayers increased with increase of copper containing ratio. And, specific heat gradually decreased with increase of copper containing ratio.

  7. Effect of thermally stable Cu- and Mg-rich aluminides on the high temperature strength of an AlSi12CuMgNi alloy

    SciTech Connect

    Asghar, Z.

    2014-02-15

    The internal architecture of an AlSi12CuMgNi piston alloy, revealed by synchrotron tomography, consists of three dimensional interconnected hybrid networks of Cu-rich aluminides, Mg-rich aluminides and eutectic/primary Si embedded in an α-Al matrix. The strength at room temperature and at 300°C is studied as a function of solution treatment time at 490°C and compared with results previously reported for an AlSi12Ni alloy. The addition of 1 wt% Cu and 1 wt% Mg to AlSi12CuMgNi increases the room temperature strength by precipitation hardening while the strength at 300°C is similar for both alloys in as-cast condition. The strength of AlSi12CuMgNi decreases with solution treatment time and stabilizes at 4 h solution treatment. The effect of solution treatment time on the strength of the AlSi12CuMgNi alloy is less pronounced than for the AlSi12Ni alloy both at room temperature and at 300°C. - Highlights: • The 3D microstructure of AlSi12CuMgNi is revealed by synchrotron tomography. • An imaging analysis procedure to segment phases with similar contrasts is presented. • 1 wt% Cu and Mg results in the formation of 3D networks of rigid phases. • AlSi12CuMgNi is stronger than AlSi12Ni owing to the stability of the 3D networks.

  8. Low thermal budget photonic processing of highly conductive Cu interconnects based on CuO nanoinks. Potential for flexible printed electronics

    DOE PAGES [OSTI]

    Rager, Matthew S.; Aytug, Tolga; Veith, Gabriel M.; Joshi, Pooran C.

    2015-12-31

    The developing field of printed electronics nanoparticle based inks such as CuO show great promise as a low-cost alternative to other metal-based counterparts (e.g., silver). In particular, CuO inks significantly eliminate the issue of particle oxidation, before and during the sintering process, that is prevalent in Cu-based formulations. We report here the scalable and low-thermal budget photonic fabrication of Cu interconnects employing a roll-to-roll compatible pulse-thermal-processing (PTP) technique that enables phase reduction and subsequent sintering of inkjet-printed CuO patterns onto flexible polymer templates. Detailed investigations of curing and sintering conditions were performed to understand the impact of PTP system conditionsmore » on the electrical performance of the Cu patterns. Specifically, the impact of energy and power of photonic pulses on print conductivity was systematically studied by varying the following key processing parameters: pulse intensity, duration and sequence. Through optimization of such parameters, highly conductive prints in < 1 s with resistivity values as low as 100 n m has been achieved. We also observed that the introduction of an initial ink-drying step in ambient atmosphere, after the printing and before sintering, leads to significant improvements in mechanical integrity and electrical performance of the printed Cu patterns. Moreover, the viability of CuO reactive inks, coupled with the PTP technology and pre ink-drying protocols, has also been demonstrated for the additive integration of a low-cost Cu temperature sensor onto a flexible polymer substrate.« less

  9. Low thermal budget photonic processing of highly conductive Cu interconnects based on CuO nanoinks. Potential for flexible printed electronics

    SciTech Connect

    Rager, Matthew S.; Aytug, Tolga; Veith, Gabriel M.; Joshi, Pooran C.

    2015-12-31

    The developing field of printed electronics nanoparticle based inks such as CuO show great promise as a low-cost alternative to other metal-based counterparts (e.g., silver). In particular, CuO inks significantly eliminate the issue of particle oxidation, before and during the sintering process, that is prevalent in Cu-based formulations. We report here the scalable and low-thermal budget photonic fabrication of Cu interconnects employing a roll-to-roll compatible pulse-thermal-processing (PTP) technique that enables phase reduction and subsequent sintering of inkjet-printed CuO patterns onto flexible polymer templates. Detailed investigations of curing and sintering conditions were performed to understand the impact of PTP system conditions on the electrical performance of the Cu patterns. Specifically, the impact of energy and power of photonic pulses on print conductivity was systematically studied by varying the following key processing parameters: pulse intensity, duration and sequence. Through optimization of such parameters, highly conductive prints in < 1 s with resistivity values as low as 100 n m has been achieved. We also observed that the introduction of an initial ink-drying step in ambient atmosphere, after the printing and before sintering, leads to significant improvements in mechanical integrity and electrical performance of the printed Cu patterns. Moreover, the viability of CuO reactive inks, coupled with the PTP technology and pre ink-drying protocols, has also been demonstrated for the additive integration of a low-cost Cu temperature sensor onto a flexible polymer substrate.

  10. Effect of gamma irradiation on electrical properties of Cu nanowires

    SciTech Connect

    Rana, Pallavi Gehlawat, Devender Chauhan, R. P.

    2014-04-24

    Metallic nanowires are of great interest due to their unique electrical, optical, chemical and magnetic properties. Characterization and explanations of electronic properties of nanowires are extremely important due to their potential applications in the field of nanoelectronics and optoelectronics. In the present study, we synthesized the copper nanowires of different diameters (80nm, 100nm and 200nm) and exposed them with gamma rays of 100 KGy and 150 KGy doses. The I-V characteristics of different diameter of Cu nanowires before and after the irradiation were recorded.

  11. Cu-Ni-Fe anodes having improved microstructure

    DOEpatents

    Bergsma, S. Craig; Brown, Craig W.

    2004-04-20

    A method of producing aluminum in a low temperature electrolytic cell containing alumina dissolved in an electrolyte. The method comprises the steps of providing a molten electrolyte having alumina dissolved therein in an electrolytic cell containing the electrolyte. A non-consumable anode and cathode is disposed in the electrolyte, the anode comprised of Cu--Ni--Fe alloys having single metallurgical phase. Electric current is passed from the anode, through the electrolyte to the cathode thereby depositing aluminum on the cathode, and molten aluminum is collected from the cathode.

  12. La??xSrxCuO? superconductor nanowire devices

    DOE PAGES [OSTI]

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

    2014-07-02

    La??xSrxCuO? 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.

  13. Recrystallization method to selenization of thin-film Cu(In,Ga)Se.sub.2 for semiconductor device applications

    DOEpatents

    Albin, David S.; Carapella, Jeffrey J.; Tuttle, John R.; Contreras, Miguel A.; Gabor, Andrew M.; Noufi, Rommel; Tennant, Andrew L.

    1995-07-25

    A process for fabricating slightly Cu-poor thin-films of Cu(In,Ga)Se.sub.2 on a substrate for semiconductor device applications includes the steps of forming initially a slightly Cu-rich, phase separated, mixture of Cu(In,Ga)Se.sub.2 :Cu.sub.x Se on the substrate in solid form followed by exposure of the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture to an overpressure of Se vapor and (In,Ga) vapor for deposition on the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture while simultaneously increasing the temperature of the solid mixture toward a recrystallization temperature (about 550.degree. C.) at which Cu(In,Ga)Se.sub.2 is solid and Cu.sub.x Se is liquid. The (In,Ga) flux is terminated while the Se overpressure flux and the recrystallization temperature are maintained to recrystallize the Cu.sub.x Se with the (In, Ga) that was deposited during the temperature transition and with the Se vapor to form the thin-film of slightly Cu-poor Cu.sub.x (In,Ga).sub.y Se.sub.z. The initial Cu-rich, phase separated large grain mixture of Cu(In,Ga)Se.sub.2 :Cu.sub.x Se can be made by sequentially depositing or co-depositing the metal precursors, Cu and (In, Ga), on the substrate at room temperature, ramping up the thin-film temperature in the presence of Se overpressure to a moderate anneal temperature (about 450.degree. C.) and holding that temperature and the Se overpressure for an annealing period. A nonselenizing, low temperature anneal at about 100.degree. C. can also be used to homogenize the precursors on the substrates before the selenizing, moderate temperature anneal.

  14. 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

    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.

  15. Oxygen chemisorption on Cu(19 19 1) studied by spot profile analysis low-energy electron diffraction

    SciTech Connect

    Brandstetter, T.; Draxler, M.; Hohage, M.; Zeppenfeld, P.

    2007-12-15

    Cu(110) and the vicinal Cu(19 19 1) surfaces were characterized by recording maps of the reciprocal space by means of spot profile analysis low-energy electron diffraction (SPA-LEED). For both surfaces, kinematic simulations were performed to get insight into the main features of the experimental data. Furthermore, it is shown that chemisorption of oxygen and subsequent annealing lead to the formation of a Cu-CuO stripe phase and induce faceting of the Cu(19 19 1) surface. The evolution from the clean Cu(19 19 1) surface to the coexistence of the (110) and (111) facets with increasing oxygen exposure was characterized by SPA-LEED.

  16. Man-made objects cuing in satellite imagery

    SciTech Connect

    Skurikhin, Alexei N

    2009-01-01

    We present a multi-scale framework for man-made structures cuing in satellite image regions. The approach is based on a hierarchical image segmentation followed by structural analysis. A hierarchical segmentation produces an image pyramid that contains a stack of irregular image partitions, represented as polygonized pixel patches, of successively reduced levels of detail (LOOs). We are jumping off from the over-segmented image represented by polygons attributed with spectral and texture information. The image is represented as a proximity graph with vertices corresponding to the polygons and edges reflecting polygon relations. This is followed by the iterative graph contraction based on Boruvka's Minimum Spanning Tree (MST) construction algorithm. The graph contractions merge the patches based on their pairwise spectral and texture differences. Concurrently with the construction of the irregular image pyramid, structural analysis is done on the agglomerated patches. Man-made object cuing is based on the analysis of shape properties of the constructed patches and their spatial relations. The presented framework can be used as pre-scanning tool for wide area monitoring to quickly guide the further analysis to regions of interest.

  17. Shock-induced consolidation and spallation of Cu nanopowders

    SciTech Connect

    Huang, L.; Han, W. Z.; Luo, S. N.; An, Q.; Goddard, W. A. III

    2012-01-01

    A useful synthesis technique, shock synthesis of bulk nanomaterials from nanopowders, is explored here with molecular dynamics simulations. We choose nanoporous Cu ({approx}11 nm in grain size and 6% porosity) as a representative system, and perform consolidation and spallation simulations. The spallation simulations characterize the consolidated nanopowders in terms of spall strength and damage mechanisms. The impactor is full density Cu, and the impact velocity (u{sub i}) ranges from 0.2 to 2 km s{sup -1}. We present detailed analysis of consolidation and spallation processes, including atomic-level structure and wave propagation features. The critical values of u{sub i} are identified for the onset plasticity at the contact points (0.2 km s{sup -1}) and complete void collapse (0.5 km s{sup -1}). Void collapse involves dislocations, lattice rotation, shearing/friction, heating, and microkinetic energy. Plasticity initiated at the contact points and its propagation play a key role in void collapse at low u{sub i}, while the pronounced, grain-wise deformation may contribute as well at high u{sub i}. The grain structure gives rise to nonplanar shock response at nanometer scales. Bulk nanomaterials from ultrafine nanopowders ({approx}10 nm) can be synthesized with shock waves. For spallation, grain boundary (GB) or GB triple junction damage prevails, while we also observe intragranular voids as a result of GB plasticity.

  18. Controlled preparation of Ag–Cu{sub 2}O nanocorncobs and their enhanced photocatalytic activity under visible light

    SciTech Connect

    Yang, Siyuan; Zhang, Shengsen; Wang, Hongjuan; Yu, Hao; Fang, Yueping; Peng, Feng

    2015-10-15

    Graphical abstract: The corncob-like Ag–Cu{sub 2}O nanostructure with suitably exposed Ag surface exhibited much higher photocatalytic activity than Ag@Cu{sub 2}O nanocables and Cu{sub 2}O nanowires. - Highlights: • Ag–Cu{sub 2}O nanocorncobs have been controllably prepared by a simple synthesis. • The possible formation mechanism of Ag–Cu{sub 2}O has been studied. • Ag–Cu{sub 2}O exhibits noticeable improved photocurrent compared with the pure Cu{sub 2}O NWs. • Ag–Cu{sub 2}O with suitably exposed Ag surface shows much higher photocatalytic activity. - Abstract: Novel corncob-like nano-heterostructured Ag–Cu{sub 2}O photocatalyst has been controllably prepared by adjusting the synthetic parameters, and the possible formation mechanism has been also studied. The photoelectrochemical and photocatalytic performances demonstrated that the as-prepared Ag–Cu{sub 2}O nanocorncobs exhibited higher photocatalytic activity than both pure Cu{sub 2}O nanowires and cable-like Ag@Cu{sub 2}O nano-composites. It was concluded that Ag–Cu{sub 2}O nanocorncobs with suitably exposed Ag surface not only effectively inhibit the recombination of electron–hole pairs but also suitably increase the active sites of electronic conduction, and thus increasing the photocatalytic activity under visible light irradiation.

  19. J/psi production at high transverse momenta in p+p and Cu+Cu collisions at sqrt sNN = 200 GeV

    SciTech Connect

    STAR Collaboration; Abelev, B. I.

    2009-10-27

    The STAR collaboration at RHIC presents measurements of J/{psi} {yields} e{sup +}e{sup -} at mid-rapidity and high transverse momentum (p{sub T} > 5 GeV/c) in p+p and central Cu+Cu collisions at {radical}sNN = 200 GeV. The inclusive J/{psi} production cross section for Cu+Cu collisions is found to be consistent at high p{sub T} with the binary collision-scaled cross section for p+p collisions, in contrast to previous measurements at lower p{sub T}, where a suppression of J/{psi} production is observed relative to the expectation from binary scaling. Azimuthal correlations of J/{psi} with charged hadrons in p+p collisions provide an estimate of the contribution of B-meson decays to J/{psi} production of 13% {+-} 5%.

  20. Measurement of K0S and K*0 in p+p, d+Au, and Cu+Cu collisions at sqrt SNN = 200 GeV

    DOE PAGES [OSTI]

    Adare, A.; Aidala, C.

    2014-11-01

    The PHENIX experiment at the Relativistic Heavy Ion Collider has performed a systematic study of K0S and K*0 meson production at midrapidity in p+p, d+Au, and Cu+Cu collisions at sqrt SNN = 200 GeV. The K0S and K*0 mesons are reconstructed via their K0S and π0(→γγ)π0 (→γγ) and K*0 → K ±#25;π± decay modes, respectively. The measured transverse-momentum spectra are used to determine the nuclear modification factor of K0S and K*0 mesons in d+Au and Cu+Cu collisions at different centralities. In the d+Au collisions, the nuclear modification factor of K0S and K*0 mesons is almost constant as a function ofmore »transverse momentum and is consistent with unity showing that cold-nuclear-matter effects do not play a significant role in the measured kinematic range. In Cu+Cu collisions, within the uncertainties no nuclear modification is registered in peripheral collisions. In central collisions, both mesons show suppression relative to the expectations from the p+p yield scaled by the number of binary nucleon-nucleon collisions in the Cu+Cu system. In the pT range 2–5 GeV/c, the strange mesons ( K0S, K*0) similarly to the #30;Φ meson with hidden strangeness, show an intermediate suppression between the more suppressed light quark mesons (π0) and the nonsuppressed baryons (p, p-bar). At higher transverse momentum, pT > 5 GeV/c, production of all particles is similarly suppressed by a factor of ≈2. (auth)« less

  1. Measurement of K0S and K*0 in p+p, d+Au, and Cu+Cu collisions at sqrt SNN = 200 GeV

    DOE PAGES [OSTI]

    Adare, A.; Aidala, C.

    2014-11-01

    The PHENIX experiment at the Relativistic Heavy Ion Collider has performed a systematic study of K0S and K*0 meson production at midrapidity in p+p, d+Au, and Cu+Cu collisions at sqrt SNN = 200 GeV. The K0S and K*0 mesons are reconstructed via their K0S and π0(→γγ)π0 (→γγ) and K*0 → K ± π± decay modes, respectively. The measured transverse-momentum spectra are used to determine the nuclear modification factor of K0S and K*0 mesons in d+Au and Cu+Cu collisions at different centralities. In the d+Au collisions, the nuclear modification factor of K0S and K*0 mesons is almost constant as a functionmore » of transverse momentum and is consistent with unity showing that cold-nuclear-matter effects do not play a significant role in the measured kinematic range. In Cu+Cu collisions, within the uncertainties no nuclear modification is registered in peripheral collisions. In central collisions, both mesons show suppression relative to the expectations from the p+p yield scaled by the number of binary nucleon-nucleon collisions in the Cu+Cu system. In the pT range 2–5 GeV/c, the strange mesons ( K0S, K*0) similarly to the Φ meson with hidden strangeness, show an intermediate suppression between the more suppressed light quark mesons (π0) and the nonsuppressed baryons (p, p-bar). At higher transverse momentum, pT > 5 GeV/c, production of all particles is similarly suppressed by a factor of ≈2. (auth)« less

  2. Growth and magnetic property of antiperovskite manganese nitride films doped with Cu by molecular beam epitaxy

    SciTech Connect

    Yu, Fengmei; Ren, Lizhu; Meng, Meng; Wang, Yunjia; Yang, Mei; Wu, Shuxiang; Li, Shuwei

    2014-04-07

    Manganese nitrides thin films on MgO (100) substrates with and without Cu-doping have been fabricated by plasma assisted molecular beam epitaxy. Antiperovskite compounds Mn{sub 3.6}Cu{sub 0.4}N have been grown in the case of Cu-doping, and the pure Mn{sub 3}N{sub 2} single crystal has been obtained without Cu-doping. The Mn{sub 3.6}Cu{sub 0.4}N exhibits ferrimagnetism, and the magnetization of Mn{sub 3.6}Cu{sub 0.4}N increases upon the temperature decreasing from 300 K to 5 K, similar to Mn{sub 4}N. The exchange bias (EB) effects emerge in the Mn{sub 3.6}Cu{sub 0.4}N films. The EB behavior is originated from the interfaces between ferrimagnetic Mn{sub 3.6}Cu{sub 0.4}N and antiferromagnetic metal Mn, which is verified to be formed by the data of x-ray photoelectron spectroscopy. The present results not only provide a strategy for producing functional antiperovskite manganese nitrides, but also shed promising light on fabricating the exchange bias part of spintronic devices.

  3. Development of a Low Cost Insulated Foil Substrate for Cu(InGaSe)2 Photovoltaics

    SciTech Connect

    ERTEN ESER

    2012-01-22

    The project validated the use of stainless steel flexible substrate coated with silicone-based resin dielectric, developed by Dow Corning Corporation, for Cu(InGa)Se2 based photovoltaics. The projects driving force was the high performance of Cu(InGa)Se2 based photovoltaics coupled with potential cost reduction that could be achieved with dielectric coated SS web substrate.

  4. Compositionally graded SiCu thin film anode by magnetron sputtering for lithium ion battery

    SciTech Connect

    Polat, B. D.; Eryilmaz, O. L.; Keles, O; Erdemir, A; Amine, Khalil

    2015-10-22

    Compositionally graded and non-graded composite SiCu thin films were deposited by magnetron sputtering technique on Cu disks for investigation of their potentials in lithium ion battery applications. The compositionally graded thin film electrodes with 30 at.% Cu delivered a 1400 mAh g-1 capacity with 80% Coulombic efficiency in the first cycle and still retained its capacity at around 600 mAh g-1 (with 99.9% Coulombic efficiency) even after 100 cycles. On the other hand, the non-graded thin film electrodes with 30 at.% Cu exhibited 1100 mAh g-1 as the first discharge capacity with 78% Coulombic efficiency but the cycle life of this film degraded very quickly, delivering only 250 mAh g-1 capacity after 100th cycles. Not only the Cu content but also the graded film thickness were believed to be the main contributors to the much superior performance of the compositionally graded SiCu films. We also believe that the Cu-rich region of the graded film helped reduce internal stress build-up and thus prevented film delamination during cycling. In particular, the decrease of Cu content from interface region to the top of the coating reduced the possibility of stress build-up across the film during cycling, thus leading to a high electrochemical performance.

  5. Electronic and structural properties at the interface between CuPc and graphene

    SciTech Connect

    Tao, Yongsheng; Mao, Hongying; He, Pimo

    2015-01-07

    The electronic and structural properties at Copper phthalocyanine (CuPc)/graphene have been studied using ultraviolet photoemission spectroscopy and first-principles density function theory calculation. The five emission features ?, ?, ?, ?, and ? originating from the CuPc molecules locate at 1.48, 3.66, 4.98, 6.90, and 9.04?eV, respectively. These features shift in binding energy with the increasing CuPc coverage. The feature ? is mostly deriving from Cu 3d orbital with some contributions from C 2p orbital. Further theoretical calculation indicates that the adsorption of CuPc on a top site is the most favorable configuration, and the separation between the adsorbate and graphene is about 3.47?. According to the density of states before and after CuPc adsorption, the LUMO of CuPc is slightly occupied, while the Dirac point of graphene slightly shift towards higher energy, suggesting that a small amount of electron transfer from graphene to CuPc upon contact.

  6. Fundamental studies of high-temperature corrosion reactions. Sixth annual progress report. [Cu-6% Ni

    SciTech Connect

    Rapp, R.A.

    1981-02-01

    Research was conducted on the sulfidation of pure Mo by sulfur gases at 700 to 950/sup 0/C and on the in-situ oxidation of metals and alloys in the hot-stage SEM. Results on the in-situ oxidation of Cu, Ni, Fe, and Cu-6% Ni up to 930/sup 0/C are reported in detail. 21 figures.

  7. Ultrasound-assisted synthesis of CuO nanostructures templated by cotton fibers

    SciTech Connect

    Zou, Yunling; Li, Yan; Guo, Ying; Zhou, Qingjun; An, Dongmin

    2012-11-15

    Highlights: ? Flower-like and corn-like CuO nanostructures were synthesized by a simple method. ? Cotton fibers purchased from commercially are used as template. ? The concentration of Cu(NO{sub 3}){sub 2} solution is an important parameter. -- Abstract: Flower-like and corn-like CuO nanostructures composed of CuO nanoparticles were successfully synthesized via ultrasound-assisted template method, respectively, by controlling the initial concentration of Cu(NO{sub 3}){sub 2} solution. Here, cotton fibers were used as template agent. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM) and energy-dispersive spectroscopy (EDS), respectively. The results demonstrated that the initial concentration of Cu(NO{sub 3}){sub 2} solution was an important parameter for determining whether CuO nanoparticles assembled into flower-like structures or corn-like structures. The mechanism of forming different nanostructures of CuO was discussed.

  8. Bond Order Potentials for AlCuH and C. (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Bond Order Potentials for AlCuH and C. Citation Details In-Document Search Title: Bond Order Potentials for AlCuH and C. Abstract not provided. Authors: Zhou, Xiaowang ; Ward, Donald ; Foster, Michael E. ; Zimmerman, Jonathan A. Publication Date: 2015-07-01 OSTI Identifier: 1263961 Report Number(s): SAND2015-5559C 594950

  9. Ab-initio study of donor-acceptor codoping for n-type CuO

    SciTech Connect

    Peng, Yuan; Wang, Junling, E-mail: jlwang@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Zheng, Jianwei [Institute of High Performance Computing, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632 (Singapore); Wu, Ping [Engineering Product Development, Singapore University of Technology and Design, 20 Dover Drive, Singapore 138682 (Singapore)

    2014-10-28

    Single n-type dopant in CuO has either a deep donor level or limited solubility, inefficient in generating free electrons. We have performed ab-initio study of the donor-acceptor codoping to obtain n-type CuO. Our results show that N codoping can slightly improve the donor level of Zr and In by forming shallower n-type complexes (Zr{sub Cu}-N{sub O} and 2In{sub Cu}-N{sub O}), but their formation energies are too high to be realized in experiments. However, Li codoping with Al and Ga is found to be relatively easy to achieve. 2Al{sub Cu}-Li{sub Cu} and 2Ga{sub Cu}-Li{sub Cu} have shallower donor levels than single Al and Ga by 0.14?eV and 0.08?eV, respectively, and their formation energies are reasonably low to act as efficient codopants. Moreover, Li codoping with both Al and Ga produce an empty impurity band just below the host conduction band minimum, which may reduce the donor ionization energy at high codoping concentrations.

  10. Interaction of CuS and sulfur in Li-S battery system

    SciTech Connect

    Sun, Ke; Su, Dong; Zhang, Qing; Bock, David C.; Marschilok, Amy C.; Takeuchi, Kenneth J.; Takeuchi, Esther S.; Gan, Hong

    2015-10-27

    Lithium-Sulfur (Li-S) battery has been a subject of intensive research in recent years due to its potential to provide much higher energy density and lower cost than the current state of the art lithiumion battery technology. In this work, we have investigated Cupric Sulfide (CuS) as a capacitycontributing conductive additive to the sulfur electrode in a Li-S battery. Galvanostatic charge/discharge cycling has been used to compare the performance of both sulfur electrodes and S:CuS hybrid electrodes with various ratios. We found that the conductive CuS additive enhanced the utilization of the sulfur cathode under a 1C rate discharge. However, under a C/10 discharge rate, S:CuS hybrid electrodes exhibited lower sulfur utilization in the first discharge and faster capacity decay in later cycles than a pure sulfur electrode due to the dissolution of CuS. The CuS dissolution is found to be the result of strong interaction between the soluble low order polysulfide Li2S3 and CuS. As a result, we identified the presence of conductive copper-containing sulfides at the cycled lithium anode surface, which may degrade the effectiveness of the passivation function of the solid-electrolyte-interphase (SEI) layer, accounting for the poor cycling performance of the S:CuS hybrid cells at low rate.

  11. Interaction of CuS and sulfur in Li-S battery system

    DOE PAGES [OSTI]

    Sun, Ke; Su, Dong; Zhang, Qing; Bock, David C.; Marschilok, Amy C.; Takeuchi, Kenneth J.; Takeuchi, Esther S.; Gan, Hong

    2015-10-27

    Lithium-Sulfur (Li-S) battery has been a subject of intensive research in recent years due to its potential to provide much higher energy density and lower cost than the current state of the art lithiumion battery technology. In this work, we have investigated Cupric Sulfide (CuS) as a capacitycontributing conductive additive to the sulfur electrode in a Li-S battery. Galvanostatic charge/discharge cycling has been used to compare the performance of both sulfur electrodes and S:CuS hybrid electrodes with various ratios. We found that the conductive CuS additive enhanced the utilization of the sulfur cathode under a 1C rate discharge. However, undermore » a C/10 discharge rate, S:CuS hybrid electrodes exhibited lower sulfur utilization in the first discharge and faster capacity decay in later cycles than a pure sulfur electrode due to the dissolution of CuS. The CuS dissolution is found to be the result of strong interaction between the soluble low order polysulfide Li2S3 and CuS. As a result, we identified the presence of conductive copper-containing sulfides at the cycled lithium anode surface, which may degrade the effectiveness of the passivation function of the solid-electrolyte-interphase (SEI) layer, accounting for the poor cycling performance of the S:CuS hybrid cells at low rate.« less

  12. Preferential Cu precipitation at extended defects in bcc Fe: An atomistic study

    SciTech Connect

    Zhang, Yongfeng; Millett, Paul C.; Tonks, Michael R.; Bai, Xian-Ming; Biner, S. Bulent

    2015-04-01

    As a starting point to understand Cu precipitation in RPV alloys, molecular dynamics and Metropolis Monte-Carlo simulations are carried out to study the effect of lattice defects on Cu precipitation by taking Fe-Cu system as a model alloy. Molecular dynamics simulations show that owing to the high heat of mixing and positive size mismatch, Cu is attracted by vacancy type defects such as vacancies and voids, and tensile stress fields. In accordance, preferential precipitation of Cu is observed in Metropolis Monte-Carlo simulations at dislocations, prismatic loops and voids. The interaction of Cu with a stress field, e.g., that associated with a dislocation or a prismatic loop, is dominated by elastic effect and can be well described by the linear-elasticity theory. For prismatic loops, the attraction to Cu is found to be size-dependent with opposite trends displayed by vacancy and interstitial loops. The size-dependences can be explained by considering the stress fields produced by these loops. The current results will be useful for understanding the effect of neutron irradiation on Cu precipitation in reactor-pressure-vessel steels.

  13. Identified high-pT spectra in Cu+Cu collisions at sqrt sNN=200 GeV

    SciTech Connect

    STAR Collaboration; Abelev, Betty

    2010-07-05

    We report new results on identified (anti)proton and charged pion spectra at large transverse momenta (3 < p{sub T} < 10 GeV/c) from Cu+Cu collisions at {radical}s{sub NN} = 200 GeV using the STAR detector at the Relativistic Heavy Ion Collider (RHIC). This study explores the system size dependence of two novel features observed at RHIC with heavy ions: the hadron suppression at high-p{sub T} and the anomalous baryon to meson enhancement at intermediate transverse momenta. Both phenomena could be attributed to the creation of a new form of QCD matter. The results presented here bridge the system size gap between the available pp and Au+Au data, and allow the detailed exploration for the on-set of the novel features. Comparative analysis of all available 200 GeV data indicates that the system size is a major factor determining both the magnitude of the hadron spectra suppression at large transverse momenta and the relative baryon to meson enhancement.

  14. CuInSe/sub 2/-based photoelectrochemical cells: their use in characterization of thin CuInSe/sub 2/ films, and as photovoltaic cells per se

    SciTech Connect

    Cahen, D.; Chen, Y.W.; Ireland, P.J.; Noufi, R.; Turner, J.A.; Rincon, C.; Bachmann, K.J.

    1984-05-01

    Photoelectrochemistry has been employed to characterize the p-CuInSe/sub 2/ component of the CdS/CuInSe/sub 2/ on-metal and a nonaqueous electrolyte containing a redox couple not specifically adsorbed onto the semiconductor, we can test the films for photovoltaic activity and obtain effective electronic properties of them, before CdS deposition, in a nondestructive manner. Electrochemical decomposition of CuInSe/sub 2/ was investigated in acetonitrile solutions to determine the mechanism of decomposition (n and p) in the dark and under illumination. Electrochemical, solution chemical and surface analyses confirmed at the light-assisted decomposition of CuInSe/sub 2/ resulted in metal ions and elemental chalcogen. On the basis of the results from the electrochemical decomposition, and studies on the solid state chemistry of the (Cu/sub 2/Se)/sub x/(In/sub 2/Se/sub 3/)/sub 1-x/ system and surface analyses, the CuInSe/sub 2//polyiodide interface was stabilized and up to 11.7% conversion efficiencies were obtained.

  15. Magnetic order tuned by Cu substitution in Fe1.1–zCuzTe

    SciTech Connect

    Wen, Jinsheng; Xu, Zhijun; Xu, Guangyong; Lumsden, M. D.; Valdivia, P. N.; Bourret-Courchesne, E.; Gu, Genda; Lee, Dung-Hai; Tranquada, J. M.; Birgeneau, R. J.

    2012-07-02

    We study the effects of Cu substitution in Fe₁.₁Te, the nonsuperconducting parent compound of the iron-based superconductor, Fe₁₊yTe₁₋xSex, utilizing neutron scattering techniques. It is found that the structural and magnetic transitions, which occur at ~60 K without Cu, are monotonically depressed with increasing Cu content. By 10% Cu for Fe, the structural transition is hardly detectable, and the system becomes a spin glass below 22 K, with a slightly incommensurate ordering wave vector of (0.5–δ, 0, 0.5) with δ being the incommensurability of 0.02, and correlation length of 12 Å along the a axis and 9 Å along the c axis. With 4% Cu, both transition temperatures are at 41 K, though short-range incommensurate order at (0.42, 0, 0.5) is present at 60 K. With further cooling, the incommensurability decreases linearly with temperature down to 37 K, below which there is a first-order transition to a long-range almost-commensurate antiferromagnetic structure. A spin anisotropy gap of 4.5 meV is also observed in this compound. Our results show that the weakly magnetic Cu has a large effect on the magnetic correlations; it is suggested that this is caused by the frustration of the exchange interactions between the coupled Fe spins.

  16. Metallicity of Ca2Cu6P5 with single and double copper-pnictide layers

    DOE PAGES [OSTI]

    Li, Li; Parker, David; Chi, Miaofang; Tsoi, Georgiy M.; Vohra, Yogesh K.; Sefat, Athena S.

    2016-02-16

    Here, we report thermodynamic and transport properties, and also theoretical calculations, for Cu-based compound Ca2Cu6P5 and compare with CaCu2-dP2. Both materials have layers of edge-sharing copper pnictide tetrahedral CuP4, similar to Fe–As and Fe–Se layers (with FeAs4, FeSe4) in the iron-based superconductors. Despite the presence of this similar transition-metal pnictide layer, we find that both Ca2Cu6P5 and CaCu2-δP2 have temperature-independent magnetic susceptibility and show metallic behavior with no evidence of either magnetic ordering or superconductivity down to 1.8 K CaCu2-δP2 is slightly off-stoichiometric, with δ = 0.14. Theoretical calculations suggest that unlike Fe 3d-based magnetic materials with a large densitymore » of states (DOS) at the Fermi surface, Cu have comparatively low DOS, with the majority of the 3d spectral weight located well below Fermi level. The room-temperature resistivity value of Ca2Cu6P5 is only 9 μΩ-cm, due to a substantial plasma frequency and an inferred electron-phonon coupling λ of 0.073 (significantly smaller than that of metallic Cu). Also, microscopy result shows that Cu–Cu distance along the c-axis within the double layers can be very short (2.5 Å), even shorter than metallic elemental copper bond (2.56 Å). The value of dρ/dT for CaCu2-δP2 at 300 K is approximately three times larger than in Ca2Cu6P5, which suggests the likelihood of stronger electron-phonon coupling. This study shows that the details of Cu-P layers and bonding are important for their transport characteristics. In addition, it emphasizes the remarkable character of the DOS of ‘122’ iron-based materials, despite much structural similarities.« less

  17. Bandgap engineering of Cu(In_1-xGa_x)Se_2 absorber layers fabricated using

    Office of Scientific and Technical Information (OSTI)

    CuInSe_2 and CuGaSe_2 targets for one-step sputtering process (Journal Article) | SciTech Connect Bandgap engineering of Cu(In_1-xGa_x)Se_2 absorber layers fabricated using CuInSe_2 and CuGaSe_2 targets for one-step sputtering process Citation Details In-Document Search Title: Bandgap engineering of Cu(In_1-xGa_x)Se_2 absorber layers fabricated using CuInSe_2 and CuGaSe_2 targets for one-step sputtering process Authors: Park, Jae-Cheol ; Lee, Jeon-Ryang ; Al-Jassim, Mowafak ; Kim, Tae-Won

  18. Growth, microstructure, optical and electrical properties of sprayed CuInSe{sub 2} polycrystalline films

    SciTech Connect

    Akl, Alaa A.; Afify, H.H.

    2008-06-03

    Polycrystalline thin films of CuInSe{sub 2} have been prepared by chemical spray pyrolysis technique as a function of Cu/In ratio. Incremental growth of the various ratios followed at different substrate temperatures ranging from 548 to 623 K. Characterizations by means of compositional analysis, X-ray diffraction and spectrophotometry measurements have been carried out. Voigt profile method has been used to determine the microstructure parameter (crystallite/domain size and macrostrain). The effect of Cu/In ratio as well as substrate temperature on the optical features (absorption coefficient and band gap) of these films has been investigated. The films of different Cu/In ratios (0.9-1.1) displayed a band gap from 0.92 to 1.025 eV for direct transition. The dark resistivity measurements at room temperature of Cu-rich samples show about five orders of magnitude higher than that of In-rich samples.

  19. Mechanical properties of Al-Cu alloy-SiC composites

    SciTech Connect

    Anggara, B. S.; Handoko, E.; Soegijono, B.

    2014-09-25

    The synthesis of aluminum (Al) alloys, Al-Cu, from mixture 96.2 % Al and 3.8 % Cu has been prepared by melting process at a temperature of 1200°C. The adding 12.5 wt% up to 20 wt% of SiC on Al-Cu alloys samples has been investigated. The structure analyses were examined by X-Ray Diffractometer (XRD) and scanning electron microscope (SEM). Moreover, the morphology of Al-Cu alloys has been seen as structure in micrometer range. The hardness was measured by hardness Vickers method. According to the results, it can be assumed that the 15 wt% of SiC content is prefer content to get better quality of back to back hardness Vickers of Al-Cu alloys.

  20. Ordered defect compounds in CuInSe{sub 2} for photovoltaic solar cell application

    SciTech Connect

    Sato, K.; Katayama-Yoshida, H.

    2014-02-21

    Due to the complete compensation, defect complex (2V{sub Cu}+In{sub Cu}), namely two Cu vacancies and In located at Cu site, is stable in CuInSe{sub 2} (CIS). It is known that the series of ordered defect compounds (ODC) are constracted by ordering the defect complex. Based on the total energy calcalation by using the Korringa-Kohn-Rostoker coherent potential approxiamtion (KKR-CPA) method, we discuss phase separation of the CIS with the defect complexes into ODC and CIS. Since the band alignment between ODC and CIS is calculated to be type 2, effective electron-hole separation at the interface between ODC and CIS can be expected. This causes the enhancement of conversion efficiency of CIS-based solar cell materials.

  1. Evaluation of photovoltaic materials within the Cu-Sn-S family

    SciTech Connect

    Zawadzki, Pawel; Peng, Haowei; Ginley, David S.; Tumas, W.; Zakutayev, Andriy Lany, Stephan; Baranowski, Lauryn L.; Toberer, Eric S.

    2013-12-16

    Next-generation thin film solar cell technologies require earth abundant photovoltaic absorber materials. Here we demonstrate an alternative approach to design of such materials, evaluating candidates grouped by constituent elements rather than underlying crystal structures. As an example, we evaluate thermodynamic stability, electrical transport, electronic structure, optical and defect properties of Cu-Sn-S candidates using complementary theory and experiment. We conclude that Cu{sub 2}SnS{sub 3} avoids many issues associated with the properties of Cu{sub 4}SnS{sub 4}, Cu{sub 4}Sn{sub 7}S{sub 16}, and other Cu-Sn-S materials. This example demonstrates how this element-specific approach quickly identifies potential problems with less promising candidates and helps focusing on the more promising solar cell absorbers.

  2. Facile synthesis of Ag–Cu{sub 2}O composites with enhanced photocatalytic activity

    SciTech Connect

    Yang, Jianbo; Li, Zhen; Zhao, Caixin; Wang, Yang; Liu, Xueqin

    2014-12-15

    Highlights: • Ag–Cu{sub 2}O nanocomposites were synthesized via awet-chemical precipitation route. • The growth temperature does not exceed 50 °C in any step of the synthesis. • Enhanced photocurrent of Ag–Cu{sub 2}O composites, compared to pure Cu{sub 2}O particles. • The photocatalytic property was studied upon simulated sunlight. • Enhanced photocatalytic property of Ag–Cu{sub 2}O composites, compared to pure Cu{sub 2}O particles. - Abstract: Silver–cuprous oxide (Ag–Cu{sub 2}O) microcomposites are successfully prepared by a facile low-cost solution method. The obtained materials were characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM), ultraviolet–visible (UV–vis) spectroscopy, X-ray photoelectron spectroscopy (XPS). Experiments demonstrated that the formation of Ag–Cu{sub 2}O microcomposites was significantly influenced by the concentration of AgNO{sub 3}, and with increasing the concentration of AgNO{sub 3}, the optical absorption of the composites becomes strong. The photocatalytic activity of the prepared Ag–Cu{sub 2}O composites was determined by measuring the degradation of methyl orange solution under visible light, to find out its potential application in waste water treatment. The results reveal that the photocurrent of the composite is about 4 times higher than that of pure Cu{sub 2}O and the visible light photocatalytic activity of the composite is enhanced greatly on degradation of methyl orange. The reason for improvement in photocatalytic activity of the Ag–Cu{sub 2}O composites was also discussed.

  3. Mechanism of abnormally slow crystal growth of CuZr alloy

    SciTech Connect

    Yan, X. Q.; Lü, Y. J.

    2015-10-28

    Crystal growth of the glass-forming CuZr alloy is shown to be abnormally slow, which suggests a new method to identify the good glass-forming alloys. The crystal growth of elemental Cu, Pd and binary NiAl, CuZr alloys is systematically studied with the aid of molecular dynamics simulations. The temperature dependence of the growth velocity indicates the different growth mechanisms between the elemental and the alloy systems. The high-speed growth featuring the elemental metals is dominated by the non-activated collision between liquid-like atoms and interface, and the low-speed growth for NiAl and CuZr is determined by the diffusion across the interface. We find that, in contrast to Cu, Pd, and NiAl, a strong stress layering arisen from the density and the local order layering forms in front of the liquid-crystal interface of CuZr alloy, which causes a slow diffusion zone. The formation of the slow diffusion zone suppresses the interface moving, resulting in much small growth velocity of CuZr alloy. We provide a direct evidence of this explanation by applying the compressive stress normal to the interface. The compression is shown to boost the stress layering in CuZr significantly, correspondingly enhancing the slow diffusion zone, and eventually slowing down the crystal growth of CuZr alloy immediately. In contrast, the growth of Cu, Pd, and NiAl is increased by the compression because the low diffusion zones in them are never well developed.

  4. Three 3D hybrid networks based on octamolybdates and different Cu{sup I}/Cu{sup II}-bis(triazole) motifs

    SciTech Connect

    Zhang, Chun-Jing; Pang, Hai-Jun; Tang, Qun; Wang, Hui-Yuan; Chen, Ya-Guang

    2010-12-15

    Three 3D compounds based on octamolybdate clusters and various Cu{sup I}/Cu{sup II}-bis(triazole) motifs, [Cu{sup I}{sub 2}btb][{beta}-Mo{sub 8}O{sub 26}]{sub 0.5} (1), [Cu{sup I}{sub 2}btpe][{beta}-Mo{sub 8}O{sub 26}]{sub 0.5} (2), and [Cu{sup II}(btpe){sub 2}][{beta}-Mo{sub 8}O{sub 26}]{sub 0.5} (3) [btb=1,4-bis(1,2,4-triazol-1-yl)butane, btpe=1,5-bis(1,2,4-triazol-1-yl)pentane], were isolated via tuning flexible ligand spacer length and metal coordination preferences. In 1, the copper(I)-btb motif is a one-dimensional (1D) chain which is further linked by hexadentate {beta}-[Mo{sub 8}O{sub 26}]{sup 4-} clusters via coordinating to Cu{sup I} cations giving a 3D structure. In 2, the copper(I)-btpe motif exhibits a 'stairs'-like [Cu{sup I}{sub 2}btpe]{sup 2+} sheet, and the tetradentate {beta}-[Mo{sub 8}O{sub 26}]{sup 4-} clusters interact with two neighboring [Cu{sup I}{sub 2}btpe]{sup 2+} sheets constructing a 3D framework. In 3, the copper(II)-btpe motif possesses a novel (2D{yields}3D) interdigitated structure, which is further connected by the tetradentate {beta}-[Mo{sub 8}O{sub 26}]{sup 4-} clusters forming a 3D framework. The thermal stability and luminescent properties of 1-3 are investigated in the solid state. -- Graphical abstract: Three 3D compounds based on {beta}-[Mo{sub 8}O{sub 26}]{sup 4-} clusters with different Cu{sup I}/Cu{sup II}-bis(triazole) motifs were synthesized by regularly tuning flexible ligand spacer length and metal coordination preferences. Display Omitted

  5. Crystallization in supercooled liquid Cu: Homogeneous nucleation and growth

    SciTech Connect

    E, J. C.; Wang, L.; Luo, S. N.; Cai, Y.; Wu, H. A.

    2015-02-14

    Homogeneous nucleation and growth during crystallization of supercooled liquid Cu are investigated with molecular dynamics simulations, and the microstructure is characterized with one- and two-dimensional x-ray diffraction. The resulting solids are single-crystal or nanocrystalline, containing various defects such as stacking faults, twins, fivefold twins, and grain boundaries; the microstructure is subject to thermal fluctuations and extent of supercooling. Fivefold twins form via sequential twinning from the solid-liquid interfaces. Critical nucleus size and nucleation rate at 31% supercooling are obtained from statistical runs with the mean first-passage time and survival probability methods, and are about 14 atoms and 10{sup 32} m{sup −3}s{sup −1}, respectively. The bulk growth dynamics are analyzed with the Johnson-Mehl-Avrami law and manifest three stages; the Avrami exponent varies in the range of 1–19, which also depends on thermal fluctuations and supercooling.

  6. Effects of laser irradiation on the morphology of Cu(110)

    SciTech Connect

    Brandstetter, T.; Draxler, M.; Hohage, M.; Zeppenfeld, P.; Stehrer, T.; Heitz, J.; Georgiev, N.; Martinotti, D.; Ernst, H.-J.

    2008-07-15

    The effects of pulsed laser irradiation on the morphology of the Cu(110) surface were investigated by means of reflectance difference spectroscopy (RDS) and spot profile analysis low-energy electron diffraction (SPA-LEED). The laser light induces surface defects (adatoms and islands) as well as subsurface dislocation lines. The high surface mobility leads to efficient annealing of the surface defects even at room temperature, whereas the subsurface dislocation lines persist up to temperatures T>800 K. SPA-LEED profiles of the (00) diffraction spot from the laser irradiated surface suggest an anisotropic distribution of the subsurface line defects related to the geometry of the fcc easy glide system, which is corroborated by STM measurements. Comparative experiments using conventional Ar ion bombardment point out the distinctiveness of the morphological changes induced by laser irradiation.

  7. Electronic structure of benzene adsorbed on Ni and Cu surfaces

    SciTech Connect

    Weinelt, M.; Nilsson, A.; Wassdahl, N.

    1997-04-01

    Benzene has for a long time served as a prototype adsorption system of large molecules. It adsorbs with the molecular plane parallel to the surface. The bonding of benzene to a transition metal is typically viewed to involve the {pi} system. Benzene adsorbs weakly on Cu and strongly on Ni. It is interesting to study how the adsorption strength is reflected in the electronic structure of the adsorbate-substrate complex. The authors have used X-ray Emission (XE) and X-ray Absorption (XA) spectroscopies to selectively study the electronic states localized on the adsorbed benzene molecule. Using XES the occupied states can be studies and with XAS the unoccupied states. The authors have used beamline 8.0 and the Swedish endstation equipped with a grazing incidence x-ray spectrometer and a partial yield absorption detector. The resolution in the XES and XAS were 0.5 eV and 0.05 eV, respectively.

  8. Kondo interactions from band reconstruction in YbInCu?

    DOE PAGES [OSTI]

    Jarrige, I.; Kotani, A.; Yamaoka, H.; Tsujii, N.; Ishii, K.; Upton, M.; Casa, D.; Kim, J.; Gog, T.; Hancock, J. N.

    2015-03-27

    We combine resonant inelastic X-ray scattering (RIXS) and model calculations in the Kondo lattice compound YbInCu?, a system characterized by a dramatic increase in Kondo temperature and associated valence fluctuations below a first-order valence transition at T?42 K. The bulk-sensitive, element-specific, and valence-projected charge excitation spectra reveal an unusual quasi-gap in the Yb-derived state density which drives an instability of the electronic structure and renormalizes the low-energy effective Hamiltonian at the transition. Our results provide long-sought experimental evidence for a link between temperature-driven changes in the low-energy Kondo scale and the higher-energy electronic structure of this system.

  9. Enhanced quality thin film Cu(In,Ga)Se[sub 2] for semiconductor device applications by vapor-phase recrystallization

    DOEpatents

    Tuttle, J.R.; Contreras, M.A.; Noufi, R.; Albin, D.S.

    1994-10-18

    Enhanced quality thin films of Cu[sub w](In,Ga[sub y])Se[sub z] for semiconductor device applications are fabricated by initially forming a Cu-rich, phase-separated compound mixture comprising Cu(In,Ga):Cu[sub x]Se on a substrate to form a large-grain precursor and then converting the excess Cu[sub x]Se to Cu(In,Ga)Se[sub 2] by exposing it to an activity of In and/or Ga, either in vapor In and/or Ga form or in solid (In,Ga)[sub y]Se[sub z]. Alternatively, the conversion can be made by sequential deposition of In and/or Ga and Se onto the phase-separated precursor. The conversion process is preferably performed in the temperature range of about 300--600 C, where the Cu(In,Ga)Se[sub 2] remains solid, while the excess Cu[sub x]Se is in a liquid flux. The characteristic of the resulting Cu[sub w](In,Ga)[sub y]Se[sub z] can be controlled by the temperature. Higher temperatures, such as 500--600 C, result in a nearly stoichiometric Cu(In,Ga)Se[sub 2], whereas lower temperatures, such as 300--400 C, result in a more Cu-poor compound, such as the Cu[sub z](In,Ga)[sub 4]Se[sub 7] phase. 7 figs.

  10. Enhanced quality thin film Cu(In,Ga)Se.sub.2 for semiconductor device applications by vapor-phase recrystallization

    DOEpatents

    Tuttle, John R.; Contreras, Miguel A.; Noufi, Rommel; Albin, David S.

    1994-01-01

    Enhanced quality thin films of Cu.sub.w (In,Ga.sub.y)Se.sub.z for semiconductor device applications are fabricated by initially forming a Cu-rich, phase-separated compound mixture comprising Cu(In,Ga):Cu.sub.x Se on a substrate to form a large-grain precursor and then converting the excess Cu.sub.x Se to Cu(In,Ga)Se.sub.2 by exposing it to an activity of In and/or Ga, either in vapor In and/or Ga form or in solid (In,Ga).sub.y Se.sub.z. Alternatively, the conversion can be made by sequential deposition of In and/or Ga and Se onto the phase-separated precursor. The conversion process is preferably performed in the temperature range of about 300.degree.-600.degree. C., where the Cu(In,Ga)Se.sub.2 remains solid, while the excess Cu.sub.x Se is in a liquid flux. The characteristic of the resulting Cu.sub.w (In,Ga).sub.y Se.sub.z can be controlled by the temperature. Higher temperatures, such as 500.degree.-600.degree. C., result in a nearly stoichiometric Cu(In,Ga)Se.sub.2, whereas lower temperatures, such as 300.degree.-400.degree. C., result in a more Cu-poor compound, such as the Cu.sub.z (In,Ga).sub.4 Se.sub.7 phase.

  11. Role of Cu-Ion Doping in Cu-α-MnO2 Nanowire Electrocatalysts for the Oxygen Reduction Reaction

    SciTech Connect

    Davis, Danae J.; Lambert, Timothy N.; Vigil, Julian A.; Rodriguez, Mark A.; Brumbach, Michael T.; Coker, Eric N.; Limmer, Steven J.

    2014-07-09

    The role of Cu-ion doping in α-MnO2 electrocatalysts for the oxygen reduction reaction in alkaline electrolyte was investigated. Copper doped α-MnO2 nanowires (Cu-α-MnO2) were prepared with varying amounts of Cu2+ using a solvothermal method. The electrocatalytic dataindicates that Cu-α-MnO2 nanowires have higher terminal current densities, enhanced kinetic rate constants, and improved charge transfer resistances that trend with Cu-content, exceeding values attained by α-MnO2 alone. The observed improvement in catalytic behavior correlates with an increase in Mn3+ content for the Cu-α-MnO2 nanowires. The Mn3+/Mn4+ couple is themediator for the rate-limiting redox driven O2-/OH- exchange. It is proposed that O2 adsorbs viaan axial site (the eg orbital on the Mn3+ d4 ion) at the surface, or at edge defects, of the nanowireand that the increase in covalent nature of the nanowire with Cu-ion doping leads to stabilization of O2 adsorbates and faster rates of reduction. This work is applicable to other manganese oxide electrocatalysts and shows for the first time there is a correlation for manganese oxides between electrocatalytic activity for the ORR in alkaline electrolyte and an increase in Mn3+ character of the oxide.

  12. Thermal chemistry of the Cu-KI5 atomic layer deposition precursor on a copper surface

    SciTech Connect

    Ma, Qiang; Zaera, Francisco

    2015-01-01

    The thermal chemistry of a Cu(I) ketoiminate complex, Cu-KI5, resulting from the modification of the known Air Products CupraSelect{sup } copper CVD precursor Cu(hfac)(tmvs) designed to tether the two ligands via an isopropoxide linker, was studied under ultrahigh vacuum on a Cu(110) single-crystal surface by using a combination of temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy. Adsorption at low temperatures was determined to take place via the displacement of the vinyl ligand by the surface. Molecular desorption was seen at 210?K, and the evolution of Cu(II)-KI5{sub 2} was established to take place at 280?K, presumably from a disproportionation reaction that also leads to the deposition of Cu(0). Other sets of desorption products were seen at 150, 250, and 430?K, all containing copper atoms and small organic moieties with molecular masses below 100 amu. The latter TPD peak in particular indicates significant fragmentation of the ligands, likely at the CN bond that holds the vinylsilane-isopropoxide moiety tethered to the ketoimine fragment, and possibly also at the union between the vinylsilane and the alkoxide linker. The 430?K temperature measured for this chemistry may set an upper limit for clean Cu film deposition, but since reactivity on the surface was also found to be inhibited at higher surface coverages, it may be delayed to higher temperatures under atomic layer deposition conditions.

  13. Isothermal Solid-State Transformation Kinetics Applied to Pd/Cu Alloy Membrane Fabrication

    SciTech Connect

    Pomerantz, Natalie L; Payzant, E Andrew; Ma, Yi Hua

    2010-01-01

    In this work, time-resolved, in situ high-temperature X-ray diffraction (HT-XRD) was used to study the solid-state transformation kinetics of the formation of the fcc Pd/Cu alloy from Pd/Cu bi-layers for the purpose of fabricating sulfur tolerant Pd/Cu membranes for H2 separation. Thin layers of Pd and Cu (total ~15 wt% Cu) were deposited on porous stainless steel (PSS) with the electroless deposition method and annealed in H2 at 500, 550 and 600 C. The kinetics of the annealing process were successfully described by the Avrami nucleation and growth model showing that the annealing process was diffusion controlled and one dimensional. The activation energy for the solid-state transformation was 175 kJ/mol, which was similar to the activation energy of Pd-Cu bulk interdiffusion. Furthermore, the Avrami model was able to successfully describe the changes in permeance and activation energy observed in Pd/Cu alloy membranes during characterization as they were annealed at high temperatures.

  14. Sonochemical fabrication of Cu{sub 2}O@C/graphene nanohybrid with a hierarchical architecture

    SciTech Connect

    Xu, Jiasheng; Dang, Dinh Khoi; Chung, Jin Suk; Hur, Seung Hyun; Choi, Won Mook; Kim, Eui Jung

    2014-12-15

    A three-dimensional Cu{sub 2}O@C/graphene nanohybrid hierarchical sphere-like architecture has been successfully synthesized by a sonochemical method. The as-prepared nanocomposite has been characterized using various techniques including powder X-ray diffraction, scanning electron microscopy, field emission transmission electron microscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy and Fourier transmission infrared spectrometry. Secondary big hierarchical Cu{sub 2}O@C spheres (diameter of ∼200 nm) consist of primary small Cu{sub 2}O@C spheres (diameter of 5–10 nm), which are uniformly distributed on the graphene surface. In the primary small Cu{sub 2}O@C sphere, amorphous carbon is formed by the oxidation–reduction reaction between 1-aminopyrene and copper(II) acetate in the sonochemical process. Our facile sonochemical method may apply to the preparation of other metal oxide/graphene hierarchical nanohybrids. - Highlights: • The Cu{sub 2}O@C/graphene nanohybrid hierarchical architecture was obtained. • Secondary big hierarchical Cu{sub 2}O@C spheres (diameter of ∼200 nm) consist of primary small Cu{sub 2}O@C spheres (diameter of 5–10 nm). • 1-Aminopyrene serves as a “binding agent” operating through the π–π interactions.

  15. Single-crystalline CuGeO{sub 3} nanorods: Synthesis, characterization and properties

    SciTech Connect

    Wang, Fangfang; Xing, Yan; Su, Zhongmin; Song, Shuyan

    2013-07-15

    Graphical abstract: - Highlights: Single crystalline CuGeO{sub 3} nanorods were prepared via a hydrothermal route. The material exhibits greatly enhanced activity in photocatalytic degradation of dyes. The magnetic susceptibility measurements indicate spin-Peierls transition properties. CuGeO{sub 3} nanorods may be of potential application in future integrated optical devices. - Abstract: Single crystalline CuGeO{sub 3} nanorods with a diameter of 2035 nm and a length up to 1 ?m have been prepared via a facile hydrothermal route with the assistance of ethylenediamine. Some influencing factors such as the reaction time, reaction temperature, the volume of ethylenediamine were revealed to play crucial roles in the formation of the CuGeO{sub 3} nanorods. A possible growth mechanism was proposed based on the experimental results. Significantly, this is the first time that CuGeO{sub 3} was used as a photocatalyst for organic pollutant degradation under UV light irradiation. The reaction constant (k) of CuGeO{sub 3} nanorods was five times that of the sample prepared by solid-state reaction under UV light irradiation. Additionally, the optical and magnetic properties of CuGeO{sub 3} nanorods were systematically studied.

  16. In situ visualization of metallurgical reactions in nanoscale Cu/Sn diffusion couples

    DOE PAGES [OSTI]

    Yin, Qiyue; Stach, Eric A.; Gao, Fan; Zhou, Guangwen; Gu, Zhiyong

    2015-02-10

    The Cu–Sn metallurgical soldering reaction in two-segmented Cu–Sn nanowires is visualized by in-situ transmission electron microscopy. By varying the relative lengths of Cu and Sn segments, we show that the metallurgical reaction starts at ~ 200 ° with the formation of a Cu–Sn solid solution for the Sn/Cu length ratio smaller than 1:5 while the formation of Cu–Sn intermetallic compounds (IMCs) for larger Sn/Cu length ratios. Upon heating the nanowires up to ~ 500 °C, two phase transformation pathways occur, η-Cu₆Sn₅ → ε-Cu₃Sn → δ-Cu₄₁Sn₁₁ for nanowires with a long Cu segment and η-Cu₆Sn₅ → ε-Cu₃Sn → γ-Cu₃Sn with amore » short Cu segment. The dynamic in situ TEM visualization of the evolution of Kirkendall voids demonstrates that Cu diffuses faster both in Sn and IMCs than that of Sn in Cu₃ and IMCs, which is the underlying cause of the dependence of the IMC formation and associated phase evolution on the relative lengths of the Cu and Sn segments.« less

  17. Characterization and device performance of (AgCu)(InGa)Se2 absorber layers

    SciTech Connect

    Hanket, Gregory; Boyle, Jonathan H.; Shafarman, William N.

    2009-06-08

    The study of (AgCu)(InGa)Se2 absorber layers is of interest in that Ag-chalcopyrites exhibit both wider bandgaps and lower melting points than their Cu counterparts. (AgCu)(InGa)Se2 absorber layers were deposited over the composition range 0 < Ag/(Ag+Cu) < 1 and 0.3 < Ga/(In+Ga) < 1.0 using a variety of elemental co-evaporation processes. Films were found to be singlephase over the entire composition range, in contrast to prior studies. Devices with Ga content 0.3 < Ga/(In+Ga) <0.5 tolerated Ag incorporation up to Ag/(Ag+Cu) = 0.5 without appreciable performance loss. Ag-containing films with Ga/(In+Ga) = 0.8 showed improved device characteristics over Cu-only control samples, in particular a 30-40% increase in short-circuit current. An absorber layer with composition Ag/(Ag+Cu) = 0.75 and Ga/(In+Ga) = 0.8 yielded a device with VOC = 890 mV, JSC = 20.5mA/cm2, fill factor = 71.3%, and ? = 13.0%.

  18. Precipitates in a quasicrystal-strengthened Al–Mn–Be–Cu alloy

    SciTech Connect

    Zupanič, Franc; Wang, Di; Gspan, Cristian; Bončina, Tonica

    2015-08-15

    In this work, an Al–Mn–Be–Cu alloy was studied containing a primary and eutectic icosahedral quasicrystalline phase in the as-cast microstructure. Special attention was given to a transmission electron microscopy investigation of precipitates formed within the aluminium solid solution (Al{sub ss}) at different temperatures. At 200 °C, only binary Al–Cu precipitates (θ′) were formed. At 300 °C, icosahedral quasicrystalline (IQC) precipitates prevailed with a crystallographic orientation relationship with the Al{sub ss.} The rods of the T-phase (Al{sub 20}Mn{sub 3}Cu{sub 2}) which were precipitated above 400 °C, also had a specific orientation relationship with the Al{sub ss}. The primary and eutectic IQC microstructural constituent started to transform rapidly to the T-phase and Be{sub 4}Al(Mn,Cu) at 500 °C. - Highlights: • In a quasicrystal-strengthened Al-alloy several types of precipitates can form. • At 200 °C, only binary Al–Cu precipitates formed (Al{sub 2}Cu-θ′). • The icosahedral quasicrystalline (IQC) precipitates prevailed at 300 °C. • T-phase (Al{sub 20}Mn{sub 3}Cu{sub 2}) precipitated at temperatures above 400 °C. • The precipitation of different phases did not have a strong effect on hardness.

  19. Performance evaluation of ZnO–CuO hetero junction solid state room temperature ethanol sensor

    SciTech Connect

    Yu, Ming-Ru; Suyambrakasam, Gobalakrishnan; Wu, Ren-Jang; Department of Nanotechnology, School of Interdisciplinary Courses, Noorul Islam Centre for Higher Education, Noorul Islam University, Kumaracoil 629180, Tamil Nadu ; Chavali, Murthy; Department of Applied Chemistry, Providence University, 200 Chungchi Road, Shalu, Taichung Hsien 433, Taiwan, R.O.C

    2012-07-15

    Graphical abstract: Sensor response (resistance) curves of time were changed from 150 ppm to 250 ppm alcohol concentration of ZnO–CuO 1:1. The response and recovery times were measured to be 62 and 83 s, respectively. The sensing material ZnO–CuO is a high potential alcohol sensor which provides a simple, rapid and highly sensitive alcohol gas sensor operating at room temperature. Highlights: ► The main advantages of the ethanol sensor are as followings. ► Novel materials ZnO–CuO ethanol sensor. ► The optimized ZnO–CuO hetero contact system. ► A good sensor response and room working temperature (save energy). -- Abstract: A semiconductor ethanol sensor was developed using ZnO–CuO and its performance was evaluated at room temperature. Hetero-junction sensor was made of ZnO–CuO nanoparticles for sensing alcohol at room temperature. Nanoparticles were prepared by hydrothermal method and optimized with different weight ratios. Sensor characteristics were linear for the concentration range of 150–250 ppm. Composite materials of ZnO–CuO were characterized using X-ray diffraction (XRD), temperature-programmed reduction (TPR) and high-resolution transmission electron microscopy (HR-TEM). ZnO–CuO (1:1) material showed maximum sensor response (S = R{sub air}/R{sub alcohol}) of 3.32 ± 0.1 toward 200 ppm of alcohol vapor at room temperature. The response and recovery times were measured to be 62 and 83 s, respectively. The linearity R{sup 2} of the sensor response was 0.9026. The sensing materials ZnO–CuO (1:1) provide a simple, rapid and highly sensitive alcohol gas sensor operating at room temperature.

  20. Magnetic Dipole Moment of {sup 57,59}Cu Measured by In-Gas-Cell Laser Spectroscopy

    SciTech Connect

    Cocolios, T. E.; Andreyev, A. N.; Bastin, B.; Bree, N.; Buescher, J.; Elseviers, J.; Gentens, J.; Huyse, M.; Kudryavtsev, Yu.; Pauwels, D.; Van den Bergh, P.; Van Duppen, P.; Sonoda, T.

    2009-09-04

    For the first time, in-gas-cell laser spectroscopy study of the {sup 57,59,63,65}Cu isotopes has been performed using the 244.164 nm optical transition from the atomic ground state of copper. The nuclear magnetic dipole moments for {sup 57,59,65}Cu relative to that of {sup 63}Cu have been extracted. The new value for {sup 57}Cu of mu({sup 57}Cu)=+2.582(7)mu{sub N} is in strong disagreement with the previous literature value but in good agreement with recent theoretical and systematic predictions.

  1. Crystal structure and magnetic properties of NaCu{sup II}[(Cu{sup II}{sub 3}O)(PO{sub 4}){sub 2}Cl

    SciTech Connect

    Jin Tengteng; Liu Wei; Chen Shuang; Prots, Yurii; Schnelle, Walter; Zhao Jingtai; Kniep, Ruediger; Hoffmann, Stefan

    2012-08-15

    A new copper(II) oxide phosphate chloride, NaCu{sup II}[(Cu{sup II}{sub 3}O)(PO{sub 4}){sub 2}Cl], has been synthesized by flux synthesis. Single-crystal X-ray diffraction data show that the title compound crystallizes in the monoclinic system, space group P2{sub 1}/c (No. 14), with lattice parameters a=8.392(2) A, b=6.3960(10) A, c=16.670(2) A, {beta}=109.470(10) Degree-Sign , V=843.6(3) A{sup 3}, Z=4. The crystal structure is characterized by a complex chain of copper-centered polyhedra running along [0 1 0] which are connected by phosphate tetrahedra. The resulting three-dimensional polyhedra framework exhibits channels filled by additional copper and sodium atoms. Field and temperature dependent measurements of the specific heat and the magnetic susceptibility reveal low-dimensional magnetic behavior. The compound starts to decompose at 700 K under release of oxygen and evaporation of Cu{sup I}Cl as shown by simultaneous thermogravimetry and mass spectrometry. - Graphical abstract: The crystal structure of the new copper(II) phosphate chloride, NaCu{sup II}[(Cu{sup II}{sub 3}O)(PO{sub 4}){sub 2}Cl], exhibits linear chains of copper tetrahedra which show low-dimensional magnetic behavior proven by specific heat and magnetic susceptibility measurements. Highlights: Black-Right-Pointing-Pointer A new copper(II) oxide phosphate chloride, NaCu{sup II}[(Cu{sup II}{sub 3}O)(PO{sub 4}){sub 2}Cl], has been synthesized by flux synthesis. Black-Right-Pointing-Pointer The crystal structure comprises chains of Cu{sub 4}O tetrahedra. Black-Right-Pointing-Pointer Low-dimensional behavior has been proven by magnetic and specific heat measurements. Black-Right-Pointing-Pointer On heating, Cu{sup I}Cl and oxygen are released shown by simultaneous thermogravimetry and mass spectrometry.

  2. Plasma sprayed coatings for containment of Cu-Mg-Si metallic phase change

    Office of Scientific and Technical Information (OSTI)

    material (Journal Article) | DOE PAGES Accepted Manuscript: Plasma sprayed coatings for containment of Cu-Mg-Si metallic phase change material This content will become publicly available on January 1, 2017 Title: Plasma sprayed coatings for containment of Cu-Mg-Si metallic phase change material In this study, the performance of Y2O3-stabilized ZrO2 (YSZ), Y2O3, and Al2O3 plasma sprayed coatings are investigated for their ability to prevent attack of Haynes 230 by a near-eutectic Cu-Mg-Si

  3. Atomic-scale studies on the effect of boundary coherency on stability in twinned Cu

    SciTech Connect

    Niu, Rongmei; Han, Ke Su, Yi-Feng; Salters, Vincent J.

    2014-01-06

    The stored energy and hardness of nanotwinned (NT) Cu are related to interaction between dislocations and (111)-twin boundaries (TBs) studied at atomic scales by high-angle annular dark-field scanning transmission electron microscope. Lack of mobile dislocations at coherent TBs (CTBs) provides as-deposited NT Cu a rare combination of stability and hardness. The introduction of numerous incoherent TBs (ITBs) reduces both the stability and hardness. While storing more energy in their ITBs than in the CTBs, deformed NT Cu also exhibits high dislocation density and TB mobility and therefore has increased the driving force for recovery, coarsening, and recrystallization.

  4. Phosphorescence quenching by mechanical stimulus in CaZnOS:Cu

    SciTech Connect

    Tu, Dong; Kamimura, Sunao; Xu, Chao-Nan; Fujio, Yuki; Sakata, Yoshitaro; Ueno, Naohiro

    2014-07-07

    We have found that phosphorescence intensity of CaZnOS:Cu decreased visibly under an applied load. This mechanical quenching (MQ) of phosphorescence in CaZnOS:Cu corresponded to the mechanical stimuli. We have thus demonstrated that the MQ of CaZnOS:Cu could be used for visualizing stress distributions in practical applications. We propose that MQ arises from non-radiative recombination due to electron-transfer from trap levels to non-radiative centers as a result of the mechanical load.

  5. Y-Ba-Cu-O films prepared by a paint-on method

    SciTech Connect

    Shih, I.; Qiu, C.X.

    1988-02-29

    Polycrystalline films of Y-Ba-Cu-O with a thickness of about 20--40 ..mu..m have been prepared on alumina substrates using a paint-on method. The liquid source used was obtained by mixing powder of Y/sub 2/O/sub 3/, BaCO/sub 3/, and CuO in liquid triethanolamine. Several Y-Ba-Cu-O films with an onset temperature of about 100 K and a zero resistance temperature of 85 K have been obtained after a short heat treatment at 1000 /sup 0/C in flowing O/sub 2/.

  6. Structural evolution in Ti-Cu-Ni metallic glasses during heating

    SciTech Connect

    Gargarella, P.; Pauly, S.; Stoica, M.; Khn, U.; Vaughan, G.; Afonso, C. R. M.; Eckert, J.

    2015-01-01

    The structural evolution of Ti{sub 50}Cu{sub 43}Ni{sub 7} and Ti{sub 55}Cu{sub 35}Ni{sub 10} metallic glasses during heating was investigated by in-situ synchrotron X-ray diffraction. The width of the most intense diffraction maximum of the glassy phase decreases slightly during relaxation below the glass transition temperature. Significant structural changes only occur above the glass transition manifesting in a change in the respective peak positions. At even higher temperatures, nanocrystals of the shape memory B2-Ti(Cu,Ni) phase precipitate, and their small size hampers the occurrence of a martensitic transformation.

  7. Mixed-sputter deposition of Ni-Ti-Cu shape memory films

    SciTech Connect

    Krulevitch, P.; Ramsey, P.B.; Makowiecki, D.M.; Lee, A.P.; Northrup, M.A.; Johnson, G.C.

    1994-05-01

    Ni-Ti-Cu shape memory films were mixed-sputter deposited from separate nickel, titanium, and copper targets, providing increased compositional flexibility. Shape memory characteristics, examined for films with 7 at. % Cu and 41--51 at. % Tl, were determined with temperature controlled substrate curvature measurements, and microstructure was studied with transmission electron microscopy. The Ni-Ti-Cu films were found to have shape memory properties comparable to bulk materials, with transformation temperatures between 20 and 62{degree}C, a 10--13{degree}C hysteresis, and up to 330 MPa recoverable stress.

  8. 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

    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+}.

  9. Synthesis, structure and properties of new chain cuprates, Na{sub 3}Cu{sub 2}O{sub 4} and Na{sub 8}Cu{sub 5}O{sub 10}

    SciTech Connect

    Sofin, Mikhail; Peters, Eva-Maria; Jansen, Martin . E-mail: jansen@fkf.mpg.de

    2005-12-15

    Na{sub 3}Cu{sub 2}O{sub 4} and Na{sub 8}Cu{sub 5}O{sub 10} were prepared via the azide/nitrate route from stoichiometric mixtures of the precursors CuO, NaN{sub 3} and NaNO{sub 3}. Single crystals have been grown by subsequent annealing of the as prepared powders at 500 deg. C for 2000h in silver crucibles, which were sealed in glass ampoules under dried Ar. According to the X-ray analysis of the crystal structures (Na{sub 3}Cu{sub 2}O{sub 4}: P2{sub 1}/n, Z=4, a=5.7046(2), b=11.0591(4), c=8.0261(3)A, {beta}=108.389(1){sup o}, 2516 independent reflections, R{sub 1}(all)=0.0813, wR{sub 2} (all)=0.1223; Na{sub 8}Cu{sub 5}O{sub 10}: Cm, Z=2, a=8.228(1), b=13.929(2), c=5.707(1)A, {beta}=111.718(2){sup o}, 2949 independent reflections, R{sub 1}(all)=0.0349, wR{sub 2} (all)=0.0850), the main feature of both crystal structures are CuO{sub 2} chains built up from planar, edge-sharing CuO{sub 4} squares. From the analysis of the Cu-O bond lengths, the valence states of either +2 or +3 can be unambiguously assigned to each copper atom. In Na{sub 3}Cu{sub 2}O{sub 4} these ions alternate in the chains, in Na{sub 8}Cu{sub 5}O{sub 10} the periodically repeated part consists of five atoms according to Cu{sup II}-Cu{sup II}-Cu{sup III}-Cu{sup II}-Cu{sup III}. The magnetic susceptibilities show the dominance of antiferromagnetic interactions. At high temperatures the compounds exhibit Curie-Weiss behaviour (Na{sub 3}Cu{sub 2}O{sub 4}: {mu}=1.7{mu}{sub B}, {theta}=-160K, Na{sub 8}Cu{sub 5}O{sub 10}: {mu}=1.8{mu}{sub B}, {theta}=-58K, magnetic moments per divalent copper ion). Antiferromagmetic ordering is observed to occur in these compounds below 13K (Na{sub 3}Cu{sub 2}O{sub 4}) and 24K (Na{sub 8}Cu{sub 5}O{sub 10})

  10. Effect of Cu2+ Activation on Interfacial Water Structure at the Sphalerite Surface as Studied by Molecular Dynamics Simulation

    SciTech Connect

    Jin, Jiaqi; Miller, Jan D.; Dang, Liem X.; Wick, Collin D.

    2015-12-10

    In the first part of this paper, an experimental contact angle study of the fresh and Cu2+ activated sphalerite-ZnS surface as well as the covellite-CuS (001) surface is reported describing the increased hydrophobic character of the surface during Cu2+ activation. In addition to these experimental results, the fresh sphalerite-ZnS (110), copper-zinc sulfide-CuZnS2 (110), villamaninite- CuS2 (100), and covellite-CuS (001) surfaces were examined using Molecular Dynamics Simulation (MDS). Our MDS results on the behavior of interfacial water at the fresh sphalerite-ZnS (110), copper-zinc sulfide-CuZnS2 (110), villamaninite-CuS2 (100), and covellite-CuS (001) surfaces include simulated contact angles, water number density distribution, water dipole orientation, water residence time, and hydrogen-bonding considerations. The copper content at the Cu2+ activated sphalerite surface seems to account for the increased hydrophobicity as revealed by both experimental and MD simulated contact angle measurements. The relatively greater hydrophobic character developed at the Cu2+ activated sphalerite surface and at the copper-zinc sulfide surface has been described by MDS, based on the structure of interfacial water and its dynamic properties. L.X.D. acknowledges funding from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences.

  11. Polycrystalline oxides formation during transient oxidation of (001) Cu-Ni binary alloys studied by in situ TEM and XRD.

    SciTech Connect

    Yang, J. C.; Li, Z. Q.; Sun, L.; Zhou, G. W.; Eastman, J. A.; Fong, D. D.; Fuoss, P. H.; Baldo, P. M.; Rehn, L. E.; Thompson, L. J.; Materials Science Division; Univ.of Pittsburgh; State Univ. of New York at Binghamton

    2009-01-01

    The nucleation and growth of Cu{sub 2}O and NiO islands due to oxidation of Cu{sub x}Ni{sub 1-x} (001) films were monitored, at various temperatures, by in situ ultra-high vacuum (UHV) transmission electron microscopy (TEM) and in situ synchrotron X-ray diffraction (XRD). In remarkable contrast to our previous observations of Cu and Cu-Au oxidation, irregular-shaped polycrystalline oxide islands formed with respect to the Cu-Ni alloy film, and an unusual second oxide nucleation stage was noted. In situ XRD experiments revealed that NiO formed first epitaxially, then other orientations appeared, and finally polycrystalline Cu{sub 2}O developed as the oxidation pressure was increased. The segregation of Ni and Cu towards or away, respectively, from the alloy surface during oxidation could disrupt the surface and cause polycrystalline oxide formation.

  12. A Theoretical Study of Methanol Synthesis from CO(2) Hydrogenation on Metal-doped Cu(111) Surfaces

    SciTech Connect

    Liu P.; Yang, Y.; White, M.G.

    2012-01-12

    Density functional theory (DFT) calculations and Kinetic Monte Carlo (KMC) simulations were employed to investigate the methanol synthesis reaction from CO{sub 2} hydrogenation (CO{sub 2} + 3H{sub 2} {yields} CH{sub 3}OH + H{sub 2}O) on metal-doped Cu(111) surfaces. Both the formate pathway and the reverse water-gas shift (RWGS) reaction followed by a CO hydrogenation pathway (RWGS + CO-Hydro) were considered in the study. Our calculations showed that the overall methanol yield increased in the sequence: Au/Cu(111) < Cu(111) < Pd/Cu(111) < Rh/Cu(111) < Pt/Cu(111) < Ni/Cu(111). On Au/Cu(111) and Cu(111), the formate pathway dominates the methanol production. Doping Au does not help the methanol synthesis on Cu(111). Pd, Rh, Pt, and Ni are able to promote the methanol production on Cu(111), where the conversion via the RWGS + CO-Hydro pathway is much faster than that via the formate pathway. Further kinetic analysis revealed that the methanol yield on Cu(111) was controlled by three factors: the dioxomethylene hydrogenation barrier, the CO binding energy, and the CO hydrogenation barrier. Accordingly, two possible descriptors are identified which can be used to describe the catalytic activity of Cu-based catalysts toward methanol synthesis. One is the activation barrier of dioxomethylene hydrogenation, and the other is the CO binding energy. An ideal Cu-based catalyst for the methanol synthesis via CO{sub 2} hydrogenation should be able to hydrogenate dioxomethylene easily and bond CO moderately, being strong enough to favor the desired CO hydrogenation rather than CO desorption but weak enough to prevent CO poisoning. In this way, the methanol production via both the formate and the RWGS + CO-Hydro pathways can be facilitated.

  13. Non-Equilibrium Superconductivity and Quasiparticle Dynamics in YBaCuO

    SciTech Connect

    Siders, J.L.W.; Jacobs, R.N.; Siders, C.W.; Trugman, S.A.; Taylor, A.J.

    1999-05-21

    The authors use optical pump, coherent terahertz probe spectroscopy to transiently excite nonequilibrium populations of quasiparticles in YBa{sub 2}Cu{sub 3}O{sub 7.{delta}} and monitor, with picosecond resolution, the superfluid and quasiparticle dynamics.

  14. Supported Au-CuO Catalysts for Low Temperature CO Oxidation

    Energy.gov [DOE]

    Catalytic properties of Au-CuOx/SiO2 are investigated in removing pollutants from simulated automotive exhaust to meet an increasing demand for high emissions control at low temperatures.

  15. Measurement of Cross Sections for the 63Cu(alpha,gamma)67Ga Reaction...

    Office of Scientific and Technical Information (OSTI)

    Title: Measurement of Cross Sections for the 63Cu(alpha,gamma)67Ga Reaction from 5.9-8.7 MeV Authors: Basunia, M S ; Norman, E B ; Shugart, H A ; Smith, A R ; Dolinski, M J ; ...

  16. Metallicity of Ca2Cu6P5 with single and double copper-pnictide...

    Office of Scientific and Technical Information (OSTI)

    Metallicity of Ca2Cu6P5 with single and double copper-pnictide layers Citation Details In-Document Search This content will become publicly available on February 16, 2017 Title: ...

  17. Critical CuI buffer layer surface density for organic molecular crystal orientation change

    SciTech Connect

    Ahn, Kwangseok; Kim, Jong Beom; Lee, Dong Ryeol; Kim, Hyo Jung; Lee, Hyun Hwi

    2015-01-21

    We have determined the critical surface density of the CuI buffer layer inserted to change the preferred orientation of copper phthalocyanine (CuPc) crystals grown on the buffer layer. X-ray reflectivity measurements were performed to obtain the density profiles of the buffer layers and out-of-plane and 2D grazing-incidence X-ray diffraction measurements were performed to determine the preferred orientations of the molecular crystals. Remarkably, it was found that the preferred orientation of the CuPc film is completely changed from edge-on (1 0 0) to face-on (1 1 −2) by a CuI buffer layer with a very low surface density, so low that a large proportion of the substrate surface is bare.

  18. Understanding the Deactivation Mechanisms of Cu/Zeolite SCR Catalysts in Diesel Application

    Energy.gov [DOE]

    To understand the durability of Cu/Zeolite urea-SCR catalysts in diesel applications, the effects of engine and lab aging on catalyst reactivity and material properties were investigated.

  19. Broken Symmetry in the Pseudogap State of YBa2Cu3O6+x (Technical...

    Office of Scientific and Technical Information (OSTI)

    Title: Broken Symmetry in the Pseudogap State of YBa2Cu3O6+x Authors: Ramshaw, Brad 1 + Show Author Affiliations Los Alamos National Laboratory Los Alamos National Laboratory ...

  20. Measurement of cross sections for the Cu-63(alpha,gamma)Ga-67...

    Office of Scientific and Technical Information (OSTI)

    Title: Measurement of cross sections for the Cu-63(alpha,gamma)Ga-67 reaction from 5.9-8.7 MeV Authors: Basunia, M S ; Norman, E B ; Shugart, H A ; Smith, A R ; Dolinski, M J ; ...

  1. Method of synthesizing and growing copper-indium-diselenide (CuInSe.sub.2) crystals

    DOEpatents

    Ciszek, Theodore F.

    1987-01-01

    A process for preparing CuInSe.sub.2 crystals includes melting a sufficient quantity of B.sub.2 O.sub.3 along with stoichiometric quantities of Cu, In, and Se in a crucible in a high pressure atmosphere of inert gas to encapsulate the CuInSe.sub.2 melt and confine the Se to the crucible. Additional Se in the range of 1.8 to 2.2 percent over the stoichiometric quantity is preferred to make up for small amounts of Se lost in the process. The crystal is grown by inserting a seed crystal through the B.sub.2 O.sub.3 encapsulate into contact with the CuInSe.sub.2 melt and withdrawing the seed upwardly to grow the crystal thereon from the melt.

  2. Method of synthesizing and growing copper-indium-diselenide (CuInSe/sub 2/) crystals

    DOEpatents

    Ciszek, T.F.

    1984-11-29

    A process for preparing CuInSe/sub 2/ crystals includes melting a sufficient quantity of B/sub 2/O/sub 2/ along with stochiometric quantities of Cu, In, and Se in a crucible in a high-pressure atmosphere of inert gas to encapsulate the CuInSe/sub 2/ melt and confine the Se to the crucible. Additional Se in the range of 1.8 to 2.2% over the stochiometric quantity is preferred to make up for small amounts of Se lost in the process. The melt can then be cooled slowly to form the crystal as direct solidification, or the crystal can be grown by inserting a seed crystal through the B/sub 2/O/sub 3/ encapsulate into contact with the CuInSe/sub 2/ melt and withdrawing the seed upwardly to grow the crystal thereon from the melt.

  3. Time-resolved soft x-ray spectra from laser-produced Cu plasma...

    Office of Scientific and Technical Information (OSTI)

    Cu plasma The volumetric heating of a thin copper target has been studied with time resolved x-ray spectroscopy. The copper target was heated from a plasma produced using ...

  4. Magnetization of underdoped YBa 2 Cu 3 O y above the irreversibility...

    Office of Scientific and Technical Information (OSTI)

    Title: Magnetization of underdoped YBa 2 Cu 3 O y above the irreversibility field Authors: Yu, Jing Fei ; Ramshaw, B. J. ; Kokanovi, I. ; Modic, K. A. ; Harrison, N. ; Day, James ...

  5. First-principles study of roles of Cu and Cl in polycrystalline CdTe

    DOE PAGES [OSTI]

    Yang, Ji -Hui; Yin, Wan -Jian; Park, Ji -Sang; Metzger, Wyatt; Wei, Su -Huai

    2016-01-25

    In this study, Cu and Cl treatments are important processes to achieve high efficiency polycrystalline cadmium telluride (CdTe) solar cells, thus it will be beneficial to understand the roles they play in both bulk CdTe and CdTe grain boundaries (GBs). Using first-principles calculations, we systematically study Cu and Cl-related defects in bulk CdTe. We find that Cl has only a limited effect on improving p-type doping and too much Cl can induce deep traps in bulk CdTe, whereas Cu can enhance ptype doping of bulk CdTe. In the presence of GBs, we find that, in general, Cl and Cu willmore » prefer to stay at GBs, especially for those with Te-Te wrong bonds, in agreement with experimental observations.« less

  6. Structural and thermal properties of nanocrystalline CuO synthesized by reactive magnetron sputtering

    SciTech Connect

    Verma, M.; Gupta, V. K.; Gautam, Y. K.; Dave, V.; Chandra, R.

    2014-01-28

    Recent research has shown immense application of metal oxides like CuO, MgO, CaO, Al{sub 2}O{sub 3}, etc. in different areas which includes chemical warfare agents, medical drugs, magnetic storage media and solar energy transformation. Among the metal oxides, CuO nanoparticles are of special interest because of their excellent gas sensing and catalytic properties. In this paper we report structural and thermal properties of CuO synthesized by reactive magnetron DC sputtering. The synthesized nanoparticles were characterized by X-ray diffractometer. The XRD result reveals that as DC power increased from 30W to 80W, size of the CuO nanoparticles increased. The same results have been verified through TEM analysis. Thermal properties of these particles were studied using thermogravimetry.

  7. Metallic glass alloys of Zr, Ti, Cu and Ni

    DOEpatents

    Lin, Xianghong; Peker, Atakan; Johnson, William L.

    1997-01-01

    At least quaternary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10.sup.3 K/s. Such alloys comprise titanium from 19 to 41 atomic percent, an early transition metal (ETM) from 4 to 21 atomic percent and copper plus a late transition metal (LTM) from 49 to 64 atomic percent. The ETM comprises zirconium and/or hafnium. The LTM comprises cobalt and/or nickel. The composition is further constrained such that the product of the copper plus LTM times the atomic proportion of LTM relative to the copper is from 2 to 14. The atomic percentage of ETM is less than 10 when the atomic percentage of titanium is as high as 41, and may be as large as 21 when the atomic percentage of titanium is as low as 24. Furthermore, when the total of copper and LTM are low, the amount of LTM present must be further limited. Another group of glass forming alloys has the formula (ETM.sub.1-x Ti.sub.x).sub.a Cu.sub.b (Ni.sub.1-y Co.sub.y).sub.c wherein x is from 0.1 to 0.3, y.cndot.c is from 0 to 18, a is from 47 to 67, b is from 8 to 42, and c is from 4 to 37. This definition of the alloys has additional constraints on the range of copper content, b.

  8. Electrochemical synthesis of Nb3Sn coatings on Cu substrates

    DOE PAGES [OSTI]

    Franz, S.; Barzi, E.; Turrioni, D.; Glionna, L.; Bestetti, M.

    2015-09-11

    This study aims at contributing to the development of superconducting Nb3Sn thin films for possible applications, as for instance in superconducting radio frequency (SRF) cavities. The synthesis of Nb-Sn coatings was carried out on copper substrates by electrodeposition from 1-Butyl-3-methylimidazolium chloride (BMIC) ionic liquids containing SnCl2 and NbCl5. Cyclic voltammetric curves were recorded to identify the reduction potentials of Nb and Sn ionic species. Electrodeposition was performed at 40 and 400 mA/cm2 and 130°C. The CV demonstrated that BMIC has a suitable potential window for co-deposition of Nb and Sn. The electrodeposited coatings showed a cubic Nb3Sn phase with (211)more » preferred orientation, a disordered orthorhombic NbSn2 phase and Sn-Cu phases. Film thickness was from 200 to 750 nm. These results suggest that electrodeposition of Nb-Sn coatings on copper substrates could be a suitable route to one day replace the current expensive Nb SRF cavities.« less

  9. The magnetic structure of EuCu2Sb2

    DOE PAGES [OSTI]

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

    2015-05-06

    Antiferromagnetic ordering of EuCu2Sb2 which forms in the tetragonal CaBe2Ge2-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 (Bhf) reaches 28.7(2) T at 2.1 K, indicating a full Eu2+ magnetic moment. Bhf(T) follows a smoothmore » $$S=\\frac{7}{2}$$ 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) μB 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.« less

  10. Magnetic viscosity in Ni/Cu compositionally-modulated alloys

    SciTech Connect

    Bennett, L.H.; Swartzendruber, L.J.; Ettedgui, H.; Atzmony, U.; Lashmore, D.S; Watson, R.E.; Brookhaven National Lab., Upton, NY )

    1989-01-01

    The existence of a magnetic aftereffect ( magnetic viscosity'') in Ni/Cu multilayered alloys was established using a vibrating sample magnetometer at room temperature and at 86 K. It was shown that the effect is strongly dependent on the step field, H{sub 2} (i.e., the value the field is reduced to after the magnetic moment has been aligned in high field) and exhibits a maximum relaxation rate for values of H{sub 2} around the reverse coercive field, {minus}H{sub c}. Aftereffect behavior of this type has been observed in other materials, though most often for systems composed of superparamagnetic particles, where the relaxation freezes out at low temperatures. In contrast, the relaxation in the CMA was shown to be enhanced at 86 K over its value at room temperature. New measurements over a wider temperature range show that the enhancement in this sample reaches a maximum near 120 K, but below that temperature the relaxation does freeze out. The temperature of maximum enhancement varies from sample to sample. 6 refs.

  11. 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

    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.

  12. Revealing Surface Modifications of Potassium-Fluoride-Treated Cu(In,Ga)Se 2

    Office of Scientific and Technical Information (OSTI)

    : A Study of Material Structure, Chemistry, and Photovoltaic Performance (Journal Article) | SciTech Connect Journal Article: Revealing Surface Modifications of Potassium-Fluoride-Treated Cu(In,Ga)Se 2 : A Study of Material Structure, Chemistry, and Photovoltaic Performance Citation Details In-Document Search Title: Revealing Surface Modifications of Potassium-Fluoride-Treated Cu(In,Ga)Se 2 : A Study of Material Structure, Chemistry, and Photovoltaic Performance The effects of alkali

  13. Applying Kβ Valence-to-Core X-ray Emission Spectroscopy to Cu(I) Binding

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Proteins with Relevance to Peptidylglycine Monooxygenase Reactivity | Stanford Synchrotron Radiation Lightsource Applying Kβ Valence-to-Core X-ray Emission Spectroscopy to Cu(I) Binding Proteins with Relevance to Peptidylglycine Monooxygenase Reactivity Thursday, June 30, 2016 Copper serves as a redox center in metalloproteins, often cycling between the +1 and +2 oxidation states. Oxidases, such as petidylglycine monooxygenase (PHM), bind oxygen at Cu(I) sites giving rise to "oxo"

  14. Doping Cu{sub 2}O in Electrolyte Solution: Dopant Incorporation, Atomic Structures and Electrical Properties

    SciTech Connect

    Tao, Meng; Zhang, Qiming

    2013-11-24

    We have pursued a number of research activities between April 2010 and April 2011:  A detailed study on n-type doping in Cu2O by Br;  An analysis of natural resource limitations to terawatt-scale solar cells;  Attempt to achieve a 1.4-eV direct band gap in Ni sulfides (NiSx);  First-principles studies of doping in Cu2O and electronic structures of NiSx.

  15. Understanding NOx SCR Mechanism and Activity on Cu/Chabazite Structures throughout the Catalyst Life Cycle

    SciTech Connect

    Ribeiro, Fabio; Delgass, Nick; Gounder, Rajmani; Schneider, William F.; Miller, Jeff; Yezerets, Aleksey; McEwen, Jean-Sabin; Peden, Charles HF; Howden, Ken

    2014-12-09

    Oxides of nitrogen (NOx) compounds contribute to acid rain and photochemical smog and have been linked to respiratory ailments. NOx emissions regulations continue to tighten, driving the need for high performance, robust control strategies. The goal of this project is to develop a deep, molecular level understanding of the function of Cu-SSZ-13 and Cu-SAPO-34 materials that catalyze the SCR of NOx with NH3.

  16. Thin-film polycrystalline n-ZnO/p-CuO heterojunction

    SciTech Connect

    Lisitski, O. L.; Kumekov, M. E.; Kumekov, S. E. Terukov, E. I.

    2009-06-15

    Results of X-ray diffraction and spectral-optical studies of n-ZnO and p-CuO films deposited by gas-discharge sputtering with subsequent annealing are presented. It is shown that, despite the difference in the crystal systems, the polycrystallinity of n-ZnO and p-CuO films enables fabrication of a heterojunction from this pair of materials.

  17. CU-CBR-1-I Wholesale Power Rate Schedule | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    CBR-1-I Wholesale Power Rate Schedule CU-CBR-1-I Wholesale Power Rate Schedule Area: Big Rivers and Henderson, KY System: CU This rate schedule shall be available to Big Rivers Electric Corporation and includes the City of Henderson, Kentucky. This rate schedule shall be applicable to electric capacity and energy available from the Dale Hollow, Center Hill, Wolf Creek, Cheatham, Old Hickory, Barkley, J. Percy Priest, and Cordell Hull Projects (all of such projects being hereinafter called

  18. CU-CC-1-J Wholesale Power Rate Schedule | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    CC-1-J Wholesale Power Rate Schedule CU-CC-1-J Wholesale Power Rate Schedule Area: Duke Energy Progress, Western Division System: CU This rate schedule shall be available to public bodies and cooperatives served through the facilities of Duke Energy Progress (formerly known as Carolina Power & Light Company), Western Division (hereinafter called the Customers). This rate schedule shall be applicable to electric capacity and energy available from the Dale Hollow, Center Hill, Wolf Creek,

  19. CU-CEK-1-I Wholesale Power Rate Schedule | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    CEK-1-I Wholesale Power Rate Schedule CU-CEK-1-I Wholesale Power Rate Schedule Area: East Kentucky System: CU This rate schedule shall be available to East Kentucky Power Cooperative (hereinafter called the Customer). This rate schedule shall be applicable to electric capacity and energy available from the Dale Hollow, Center Hill, Wolf Creek, Cheatham, Old Hickory, Barkley, J. Percy Priest, and Cordell Hull Projects (all of such projects being hereinafter called collectively the

  20. CU-CK-1-I Wholesale Power Rate Schedule | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    CK-1-I Wholesale Power Rate Schedule CU-CK-1-I Wholesale Power Rate Schedule Area: Kentucky Utilities System: CU This rate schedule shall be available to public bodies served through the facilities of Kentucky Utilities Company, (hereinafter called the Customers.) This rate schedule shall be applicable to electric capacity and energy available from the Dale Hollow, Center Hill, Wolf Creek, Cheatham, Old Hickory, Barkley, J. Percy Priest, and Cordell Hull Projects (all of such projects being

  1. CU-CM-1-I Wholesale Power Rate Schedule | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    CM-1-I Wholesale Power Rate Schedule CU-CM-1-I Wholesale Power Rate Schedule Area: MEAM, MDEA, and SMEPA System: CU This rate schedule shall be available to the South Mississippi Electric Power Association, Municipal Energy Agency of Mississippi, and Mississippi Delta Energy Agency. This rate schedule shall be applicable to electric capacity and energy available from the Dale Hollow, Center Hill, Wolf Creek, Cheatham, Old Hickory, Barkley, J. Percy Priest, and Cordell Hull Projects (all of such

  2. CU-CSI-1-I Wholesale Power Rate Schedule | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    CSI-1-I Wholesale Power Rate Schedule CU-CSI-1-I Wholesale Power Rate Schedule Area: Southern Illinois System: CU This rate schedule shall be available to Southern Illinois Power Cooperative (hereinafter the Customer). This rate schedule shall be applicable to electric capacity and energy available from the Dale Hollow, Center Hill, Wolf Creek, Cheatham, Old Hickory, Barkley, J. Percy Priest, and Cordell Hull Projects (all of such projects being hereinafter called collectively the

  3. CU-CTV-1-I Wholesale Power Rate Schedule | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    CTV-1-I Wholesale Power Rate Schedule CU-CTV-1-I Wholesale Power Rate Schedule Area: Tennessee Valley Authority System: CU This rate schedule shall be available to the Tennessee Valley Authority (hereinafter called TVA). This rate schedule shall be applicable to electric capacity and energy generated at the Dale Hollow, Center Hill, Wolf Creek, Old Hickory, Cheatham, Barkley, J. Percy Priest, and Cordell Hull Projects (all of such projects being hereafter called collectively the "Cumberland

  4. CU-Replacement-3 Wholesale Power Rate Schedule | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Replacement-3 Wholesale Power Rate Schedule CU-Replacement-3 Wholesale Power Rate Schedule Area: Virginia, North Carolina, Tennessee, Georgia, Alabama, Mississippi, Kentucky, southern Illinois System: CU This rate schedule shall be available to public bodies and cooperatives ( any one of whom is hereinafter called the Customer) in Virginia, North Carolina, Tennessee, Georgia, Alabama, Mississippi, Kentucky and southern Illinois to whom power is provided pursuant to contracts between the

  5. Synthesis and characterization of CuO nano particles using precipitation method

    SciTech Connect

    Malviya, Nitin; Oswal, Nidhi; Carpenter, Gopal; Gupta, Nitish

    2015-06-24

    A simple and efficient synthesis of CuO nanoparticles was carried out by precipitation method using copper metal chips as precursor and sodium hydroxide as a stabilizing agent at different calcinations temperatures (100°C, 150°C, and 175°C). The products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR). XRD indicated monoclinic structure of CuO. SEM indicated the variation in nanostructures with the heating temperatures and FTIR inidcated Cu-O stretching frequencies. The CuO nanostructures with the average particle size of about 16.52 nm were prepared at 100°C for 3 hr. When the calcinations temperature was increased to 150°C and 175°C, CuO nanostructures with the particle size of about 17.41 nm, and 18.44 nm were obtained respectively. This aqueous precipitation method can give a large scale production of CuO nanoparticles easily.

  6. Magnetic and electronic correlations in YBa sub 2 Cu sub 3 O sub 6+x

    SciTech Connect

    Tranquada, J.M.

    1989-01-01

    YBa{sub 2}Cu{sub 3}O{sub 6+x} is an antiferromagnetic insulator in its tetragonal phase at small x, and it becomes a superconducting metal in the large x orthorhombic phase. The transition between the two phases is controlled by the orientational ordering of CuO{sub x} chain segments and dielectric screening by the BaO layers. In the orthorhombic phase, holes from the chains are transferred to the CuO{sub 2} planes, and the superconducting transition temperature scales with the density of O 2p holes. The antiferromagnetic ordering in the tetragonal phase is dominated by localized Cu moments in the CuO{sub 2} planes. The two-dimensional (2D) coupling between those spins is unusually strong. The interaction between nearest-neighbor planes is sufficiently strong that spins in bilayers remain highly correlated well above the Neel temperature. Long-range order is destroyed when a significant density of O 2p holes is present in the planes; however, there is evidence that Cu moments survive and interact in the metallic phase. 55 refs., 13 figs.

  7. Magnetic order tuned by Cu substitution in Fe1.1–zCuzTe

    DOE PAGES [OSTI]

    Wen, Jinsheng; Xu, Zhijun; Xu, Guangyong; Lumsden, M. D.; Valdivia, P. N.; Bourret-Courchesne, E.; Gu, Genda; Lee, Dung-Hai; Tranquada, J. M.; Birgeneau, R. J.

    2012-07-02

    We study the effects of Cu substitution in Fe₁.₁Te, the nonsuperconducting parent compound of the iron-based superconductor, Fe₁₊yTe₁₋xSex, utilizing neutron scattering techniques. It is found that the structural and magnetic transitions, which occur at ~60 K without Cu, are monotonically depressed with increasing Cu content. By 10% Cu for Fe, the structural transition is hardly detectable, and the system becomes a spin glass below 22 K, with a slightly incommensurate ordering wave vector of (0.5–δ, 0, 0.5) with δ being the incommensurability of 0.02, and correlation length of 12 Å along the a axis and 9 Å along the cmore » axis. With 4% Cu, both transition temperatures are at 41 K, though short-range incommensurate order at (0.42, 0, 0.5) is present at 60 K. With further cooling, the incommensurability decreases linearly with temperature down to 37 K, below which there is a first-order transition to a long-range almost-commensurate antiferromagnetic structure. A spin anisotropy gap of 4.5 meV is also observed in this compound. Our results show that the weakly magnetic Cu has a large effect on the magnetic correlations; it is suggested that this is caused by the frustration of the exchange interactions between the coupled Fe spins.« less

  8. Interplay between intercalated oxygen superstructures and monolayer h -BN on Cu(100)

    DOE PAGES [OSTI]

    Ma, Chuanxu; Park, Jewook; Liu, Lei; Kim, Yong-Sung; Yoon, Mina; Baddorf, Arthur P.; Gu, Gong; Li, An-Ping

    2016-08-18

    The confinement effect of intercalated atoms in van der Waals heterostructures can lead to interesting interactions between the confined atoms or molecules and the overlaying two-dimensional (2D) materials. In this paper, we report the formation of ordered Cu(100) p(2×2) oxygen superstructures by oxygen intercalation under the monolayer hexagonal boron nitride (h-BN) on Cu after annealing. By using scanning tunneling microscopy and x-ray photoelectron spectroscopy, we identify the superstructure and reveal its roles in passivating the exposed Cu surfaces, decoupling h-BN and Cu, and disintegrating h-BN monolayers. The oxygen superstructure appears as a 2D pattern on the exposed Cu surface ormore » quasi-1D stripes of paired oxygen intercalated in the interface of h-BN and Cu predominantly oriented along the moiré modulations. The oxygen superstructure is shown to etch the overlaying h-BN monolayer in a thermal annealing process. After extended annealing, the h-BN monolayer disintegrates into nanoislands with zigzag edges. Finally, we discuss the implications of these findings on the stability and oxidation resistance of h-BN and relate them to challenges in process integration and 2D heterostructures.« less

  9. Diffusion phenomenon at the interface of Cu-brass under a strong gravitational field

    SciTech Connect

    Ogata, Yudai; Tokuda, Makoto; Januszko, Kamila; Khandaker, Jahirul Islam; Mashimo, Tsutomu; Iguchi, Yusuke; Ono, Masao

    2015-03-28

    To investigate diffusion phenomenon at the interface between Cu and brass under a strong gravitational field generated by ultracentrifuge apparatus, we performed gravity experiments on samples prepared by electroplating with interfaces normal and parallel to the direction of gravity. For the parallel-mode sample, for which sedimentation cannot occur thorough the interface, the concentration change was significant within the lower gravity region; many pores were observed in this region. Many vacancies arising from crystal strain due to the strong gravitational field moved into the lower gravity region, and enhanced the atoms mobilities. For the two normal-mode samples, which have interface normal to the direction of gravity, the composition gradient of the brass-on-Cu sample was steeper than that for Cu-on-brass. This showed that the atoms of denser Cu diffuse in the direction of gravity, whereas Zn atoms diffuse in the opposite direction by sedimentation. The interdiffusion coefficients became higher in the Cu-on-brass sample, and became lower in the brass-on-Cu sample. This rise may be related to the behavior of the vacancies.

  10. Preparation of PdCu Alloy Nanocatalysts for Nitrate Hydrogenation and Carbon Monoxide Oxidation

    DOE PAGES [OSTI]

    Cai, Fan; Yang, Lefu; Shan, Shiyao; Mott, Derrick; Chen, Bing H.; Luo, Jin; Zhong, Chuan-Jian

    2016-06-30

    Alloying Pd with Cu is important for catalytic reactions such as denitrification reaction and CO oxidation reaction, but understanding of the catalyst preparation and its correlation with the catalyst’s activity and selectivity remains elusive. Herein, we report the results of investigations of the preparation of PdCu alloy nanocatalysts using different methods and the catalytic properties of the catalysts in catalytic denitrification reaction and CO oxidation reaction. PdCu alloy nanocatalysts were prepared by conventional dry impregnation method and ligand-capping based wet chemical synthesis method, and subsequent thermochemical activation as well. The alloying characteristics depend on the bimetallic composition. PdCu/Al2O3 with amore » Pd/Cu ratio of 50:50 was shown to exhibit an optimized hydrogenation activity for the catalytic denitrification reaction. The catalytic activity of the PdCu catalysts was shown to be highly dependent on the support, as evidenced by the observation of an enhanced catalytic activity for CO oxidation reaction using TiO2 and CeO2 supports with high oxygen storage capacity. Lastly, we discussed the implications of the results to the refinement of the preparation of the alloy nanocatalysts.« less

  11. Enhanced thermoelectric performance in Cd doped CuInTe{sub 2} compounds

    SciTech Connect

    Cheng, N.; Liu, R.; Bai, S.; Shi, X. Chen, L.

    2014-04-28

    CuIn{sub 1?x}Cd{sub x}Te{sub 2} materials (x?=?0, 0.02, 0.05, and 0.1) are prepared using melting-annealing method and the highly densified bulk samples are obtained through Spark Plasma Sintering. The X-ray diffraction data confirm that nearly pure chalcopyrite structures are obtained in all the samples. Due to the substitution of Cd at In sites, the carrier concentration is greatly increased, leading to much enhanced electrical conductivity and power factor. The single parabolic band model is used to describe the electrical transport properties of CuInTe{sub 2} and the low temperature Hall mobility is also modeled. By combing theoretical model and experiment data, the optimum carrier concentration in CuInTe{sub 2} is proposed to explain the greatly enhanced power factors in the Cd doped CuInTe{sub 2}. In addition, the thermal conductivity is reduced by extra phonon scattering due to the atomic mass and radius fluctuations between Cd and In atoms. The maximum zTs are observed in CuIn{sub 0.98}Cd{sub 0.02}Te{sub 2} and CuIn{sub 0.9}Cd{sub 0.1}Te{sub 2} samples, which are improved by over 100% at room temperature and around 20% at 600?K.

  12. Cyclotron production of {sup 61}Cu using natural Zn and enriched {sup 64}Zn targets

    SciTech Connect

    Asad, A. H.; Smith, S. V.; Chan, S.; Jeffery, C. M.; Morandeau, L.; Price, R. I.

    2012-12-19

    Copper-61 ({sup 61}Cu) shares with {sup 64}Cu certain advantages for PET diagnostic imaging, but has a shorter half-life (3.4hr vs. 12.7hr) and a greater probability of positron production per disintegration (61% vs. 17.9%). One important application is for in vivo imaging of hypoxic tissue. In this study {sup 61}Cu was produced using the {sup 64}Zn(p,{alpha}){sup 61}Cu reaction on natural Zn or enriched {sup 64}Zn targets. The enriched {sup 64}Zn (99.82%) was electroplated onto high purity gold or silver foils or onto thin Al discs. A typical target bombardment used 30{mu}A; at 11.7, 14.5 or 17.6MeV over 30-60min. The {sup 61}Cu (radiochemical purity of >95%) was separated using a combination of cation and anion exchange columns. The {sup 64}Zn target material was recovered after each run, for re-use. In a direct comparison with enriched {sup 64}Zn-target results, {sup 61}Cu production using the cheaper {sup nat}Zn target proved to be an effective alternative.

  13. Complex catalytic behaviors of CuTiOx mixed-oxide during CO oxidation

    SciTech Connect

    Kim, Hyun You; Liu, Ping

    2015-09-21

    Mixed metal oxides have attracted considerable attention in heterogeneous catalysis due to the unique stability, reactivity, and selectivity. Here, the activity and stability of the CuTiOx monolayer film supported on Cu(111), CuTiOx/Cu(111), during CO oxidation was explored using density functional theory (DFT). The unique structural frame of CuTiOx is able to stabilize and isolate a single Cu+ site on the terrace, which is previously proposed active for CO oxidation. Furthermore, it is not the case, where the reaction via both the Langmuir–Hinshelwood (LH) and the Mars-van Krevelen (M-vK) mechanisms are hindered on such single Cu+ site. Upon the formation of step-edges, the synergy among Cuδ+ sites, TiOx matrix, and Cu(111) is able to catalyze the reaction well. Depending on temperatures and partial pressure of CO and O2, the surface structure varies, which determines the dominant mechanism. In accordance with our results, the Cuδ+ ion alone does not work well for CO oxidation in the form of single sites, while the synergy among multiple active sites is necessary to facilitate the reaction.

  14. Complex catalytic behaviors of CuTiOx mixed-oxide during CO oxidation

    SciTech Connect

    Kim, Hyun You; Liu, Ping

    2015-09-21

    Mixed metal oxides have attracted considerable attention in heterogeneous catalysis due to the unique stability, reactivity, and selectivity. Here, the activity and stability of the CuTiOx monolayer film supported on Cu(111), CuTiOx/Cu(111), during CO oxidation was explored using density functional theory (DFT). The unique structural frame of CuTiOx is able to stabilize and isolate a single Cu+ site on the terrace, which is previously proposed active for CO oxidation. Furthermore, it is not the case, where the reaction via both the LangmuirHinshelwood (LH) and the Mars-van Krevelen (M-vK) mechanisms are hindered on such single Cu+ site. Upon the formation of step-edges, the synergy among Cu?+ sites, TiOx matrix, and Cu(111) is able to catalyze the reaction well. Depending on temperatures and partial pressure of CO and O2, the surface structure varies, which determines the dominant mechanism. In accordance with our results, the Cu?+ ion alone does not work well for CO oxidation in the form of single sites, while the synergy among multiple active sites is necessary to facilitate the reaction.

  15. Novel Approaches to Wide Bandgap CuInSe2 Based Absorbers

    SciTech Connect

    William N. Shafarman

    2011-04-28

    This project targeted the development of high performance wide bandgap solar cells based on thin film alloys of CuInSe2 to relax constraints on module design and enable tandem solar cell structures. This addressed goals of the Solar Energy Technologies Program for Next Generation PV to develop technology needed for higher thin film module efficiency as a means to reduce costs. Specific objectives of the research project were: 1) to develop the processes and materials required to improve the performance of wide bandgap thin film solar cells based on alloys of CuInSe2, and 2) to provide the fundamental science and engineering basis for the material, electronic, and device properties required to effectively apply these processes and materials to commercial manufacture. CuInSe2-based photovoltaics have established the highest efficiencies of the thin film materials at both the cell and module scales and are actively being scaled up to commercialization. In the highest efficiency cells and modules, the optical bandgap, a function of the CuInSe2-based alloy composition, is relatively low compared to the optimum match to the solar spectrum. Wider bandgap alloys of CuInSe2 produce higher cell voltages which can improve module performance and enable the development of tandem solar cells to boost the overall efficiency. A focus for the project was alloying with silver to form (AgCu)(InGa)Se2 pentenary thin films deposited by elemental co-evaporation which gives the broadest range of control of composition and material properties. This alloy has a lower melting temperature than Ag-free, Cu-based chalcopyrite compounds, which may enable films to be formed with lower defect densities and the (AgCu)(InGa)Se2 films give improved material properties and better device performance with increasing bandgap. A comprehensive characterization of optical, structural, and electronic properties of (AgCu)(InGa)Se2 was completed over the complete compositional range 0 ≤ Ga/(In+Ga) ≤ 1 and

  16. Hydrodechlorination of 1,2-Dichloroethane Catalyzedby Dendrimer-Derived Pt-Cu/SiO2 Catalysts

    SciTech Connect

    Xie, Hong; Howe, Jane Y; Schwartz, Viviane; Monnier, J. R.; Williams, Christopher T.; Ploehn, Harry J.

    2008-01-01

    Dendrimer-metal-nanocomposites (DMNs) were used as precursors to prepare SiO2 supported monometallic Pt, Cu and bimetallic Pt-Cu catalysts with Pt/Cu atomic ratios of 1:1 (Pt50Cu50) and 1:3 (Pt25Cu75). After impregnation of these DMNs onto the support, the catalysts were thermally treated and activated following an optimized protocol. Scanning transmission electron microscopy (STEM) shows that the metal nanoparticles in dendrimer-derived SiO2-supported catalysts are smaller and have a more narrow size distribution than those in conventional catalysts prepared using corresponding metal salts via the wet impregnation method. Slow deactivation was observed for hydrodechlorination of 1,2-dichloroethane over monometallic Cu catalysts, which showed an activity about one to two orders of magnitude lower than that of the Pt-containing catalysts. Hydrodechlorination of 1,2-dichloroethane over Pt and Pt50Cu50 catalysts mainly produces ethane and the selectivity towards ethane increases with temperature. For Pt25Cu75 catalyst, the selectivity towards ethane decreases in favor of ethylene. The overall activity decreases with increasing Cu loading in the catalysts. Activity based on surface Pt sites suggests the formation of bi-functional surfaces in Pt25Cu75 catalyst favoring C-Cl bond scission on Cu sites and hydrogenation of intermediate .CH2CH2. on Pt sites. Furthermore, kinetic analyses suggest different reaction mechanisms for hydrodechlorination of 1,2-dichloroethane over Pt and Cu-enriched surfaces in the Pt-Cu bimetallic catalysts.

  17. Synthesis and anti-bacterial activity of Cu, Ag and Cu-Ag alloy nanoparticles: A green approach

    SciTech Connect

    Valodkar, Mayur; Modi, Shefaly; Pal, Angshuman; Thakore, Sonal

    2011-03-15

    Research highlights: {yields} Synthesis of novel nanosized copper-silver alloys of different compositions. {yields} Completely green approach for synthesis of water soluble bimetallic nanoparticle. {yields} Interesting anti-bacterial activity of as synthesized metal and alloy nanoparticle. -- Abstract: Metallic and bimetallic nanoparticles of copper and silver in various proportions were prepared by microwave assisted chemical reduction in aqueous medium using the biopolymer, starch as a stabilizing agent. Ascorbic acid was used as the reducing agent. The silver and copper nanoparticles exhibited surface plasmon absorption resonance maxima (SPR) at 416 and 584 nm, respectively; while SPR for the Cu-Ag alloys appeared in between depending on the alloy composition. The SPR maxima for bimetallic nanoparticles changes linearly with increasing copper content in the alloy. Transmission electron micrograph (TEM) showed monodispersed particles in the range of 20 {+-} 5 nm size. Both silver and copper nanoparticles exhibited emission band at 485 and 645 nm, respectively. The starch-stabilized nanoparticles exhibited interesting antibacterial activity with both gram positive and gram negative bacteria at micromolar concentrations.

  18. Metallic glass alloys of Zr, Ti, Cu and Ni

    DOEpatents

    Lin, X.; Peker, A.; Johnson, W.L.

    1997-04-08

    At least quaternary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10{sup 3} K/s. Such alloys comprise titanium from 19 to 41 atomic percent, an early transition metal (ETM) from 4 to 21 atomic percent and copper plus a late transition metal (LTM) from 49 to 64 atomic percent. The ETM comprises zirconium and/or hafnium. The LTM comprises cobalt and/or nickel. The composition is further constrained such that the product of the copper plus LTM times the atomic proportion of LTM relative to the copper is from 2 to 14. The atomic percentage of ETM is less than 10 when the atomic percentage of titanium is as high as 41, and may be as large as 21 when the atomic percentage of titanium is as low as 24. Furthermore, when the total of copper and LTM are low, the amount of LTM present must be further limited. Another group of glass forming alloys has the formula (ETM{sub 1{minus}x}Ti{sub x}){sub a} Cu{sub b} (Ni{sub 1{minus}y}Co{sub y}){sub c} wherein x is from 0.1 to 0.3, y{center_dot}c is from 0 to 18, a is from 47 to 67, b is from 8 to 42, and c is from 4 to 37. This definition of the alloys has additional constraints on the range of copper content, b. 2 figs.

  19. Modeling Cu Migration in CdTe Solar Cells Under Device-Processing and Long-Term Stability Conditions: Preprint

    SciTech Connect

    Teeter, G.; Asher, S.

    2008-05-01

    An impurity migration model for systems with material interfaces is applied to Cu migration in CdTe solar cells. In the model, diffusion fluxes are calculated from the Cu chemical potential gradient. Inputs to the model include Cu diffusivities, solubilities, and segregation enthalpies in CdTe, CdS and contact materials. The model yields transient and equilibrium Cu distributions in CdTe devices during device processing and under field-deployed conditions. Preliminary results for Cu migration in CdTe photovoltaic devices using available diffusivity and solubility data from the literature show that Cu segregates in the CdS, a phenomenon that is commonly observed in devices after back-contact processing and/or stress conditions.

  20. Preparation and structure characterization of SmCo{sub 5}(0001) epitaxial thin films grown on Cu(111) underlayers

    SciTech Connect

    Ohtake, Mitsuru; Nukaga, Yuri; Futamoto, Masaaki; Kirino, Fumiyoshi

    2009-04-01

    SmCo{sub 5}(0001) epitaxial films were prepared on Cu(111) single-crystal underlayers formed on Al{sub 2}O{sub 3}(0001) substrates at 500 deg. C. The nucleation and growth mechanism of (0001)-oriented SmCo{sub 5} crystal on Cu(111) underlayer is investigated and a method to control the nucleation is proposed. The SmCo{sub 5} epitaxial thin film formed directly on Cu underlayer consists of two types of domains whose orientations are rotated around the film normal by 30 deg. each other. By introducing a thin Co seed layer on the Cu underlayer, a SmCo{sub 5}(0001) single-crystal thin film is successfully obtained. Nucleation of SmCo{sub 5} crystal on Cu underlayer seems controllable by varying the interaction between the Cu underlayer and the SmCo{sub 5} layer.

  1. Nucleation and growth of oxide islands during the initial-stage oxidation of (100)Cu-Pt alloys

    SciTech Connect

    Luo, Langli; Zhou, Guangwen; Kang, Yihong; Yang, Judith C.

    2015-02-14

    The initial-stage oxidation of (100) Cu-Pt alloys has been examined by in situ environmental transmission electron microscopy and ex situ atomic force microscopy (AFM). It is shown that the oxidation proceeds via the nucleation and growth of Cu{sub 2}O islands that show dependence on the alloy composition and oxidation temperature. The kinetic measurements on the oxide nucleation reveal that both the nucleation density and surface coverage of Cu{sub 2}O islands can be promoted by alloying more Pt in the Cu-Pt alloys. Increasing the oxidation temperature above 700 °C results in the growth of large Cu{sub 2}O islands that transits to a dendritic growth morphology. The ex situ AFM studies reveal that the nucleation of oxide islands can occur on surface terraces and the subsequent oxide growth depletes local terrace Cu atoms that results in the formation of surface pits.

  2. Oxidative stress, mitochondrial permeability transition, and cell death in Cu-exposed trout hepatocytes

    SciTech Connect

    Krumschnabel, Gerhard . E-mail: Gerhard.Krumschnabel@uibk.ac.at; Manzl, Claudia; Berger, Christian; Hofer, Bettina

    2005-11-15

    We have previously shown that, in trout hepatocytes, exposure to a high dose of copper (Cu) leads to disruption of Ca{sup 2+} homeostasis and elevated formation of reactive oxygen species (ROS), with the latter ultimately causing cell death. In the present study, we aimed at identifying, using a lower Cu concentration, the role of mitochondria in this scenario, the potential involvement of the mitochondrial permeability transition (MPT), and the mode of cell death induced by the metal. Incubation with 10 {mu}M Cu resulted in a strong stimulation of ROS formation, and after 2 h of exposure a significant increase of both apoptotic and necrotic cells was seen. Co-incubation of Cu-treated hepatocytes with the iron-chelator deferoxamine significantly inhibited ROS production and completely prevented cell death. The origin of the radicals generated was at least partly mitochondrial, as visualized by confocal laser scanning microscopy. Furthermore, ROS production was diminished by inhibition of mitochondrial respiration, but since this also aggravated the elevation of intracellular Ca{sup 2+} induced by Cu, it did not preserve cell viability. In a sub-population of cells, Cu induced a decrease of mitochondrial membrane potential and occurrence of the MPT. Cyclosporin A, which did not inhibit ROS formation, prevented the onset of the MPT and inhibited apoptotic, but not necrotic, cell death. Cu-induced apoptosis therefore appears to be dependent on induction of the MPT, but the prominent contribution of mitochondria to ROS generation also suggests an important role of mitochondria in necrotic cell death.

  3. A Comparative Kinetics Study between Cu/SSZ-13 and Fe/SSZ-13 SCR Catalysts

    SciTech Connect

    Gao, Feng; Wang, Yilin; Kollar, Marton; Washton, Nancy M.; Szanyi, Janos; Peden, Charles HF

    2015-11-09

    Cu- and Fe/SSZ-13 catalysts with the same Cu(Fe)/Al ratios are synthesized using the same parent SSZ-13 starting material. The catalytic performance for both fresh and hydrothermally aged catalysts is tested with NO and NH3 oxidation, and standard SCR reactions under steady-state conditions, and standard and fast SCR under temperature-programmed conditions. For standard SCR, Cu/SSZ-13 shows much better low-temperature performance which can be explained by NH3-inhibition of Fe/SSZ-13. During hydrothermal aging, both catalysts undergo dealumination but Fe/SSZ-13 dealuminates more severely. For aged catalysts, Cu/SSZ-13 gains oxidation activities due to formation of CuOx. However, Fe/SSZ-13 loses oxidation activities although formation of FeOx clusters and FeAlOx species also occur. Because of such physical properties differences, aged Cu/SSZ-13 loses while Fe/SSZ-13 maintains high-temperature SCR selectivities. A physical mixture of aged catalysts provides stable SCR performance in a wide temperature range and is able to decrease N2O formation at high reaction temperatures. This suggests that Fe/SSZ-13 can be used as a cocatalyst for Cu/SSZ-13 for transportation applications. During temperature-programmed SCR reactions, weak hysteresis is found during standard SCR due to NH3 inhibition. For fast SCR, hysteresis caused by NH4NO3 inhibition is much more significant. NH4NO3 deposition is greatly enhanced by Brønsted and Lewis acidity of the catalysts.

  4. In situ X-ray absorption spectroscopic investigation of the electrochemical conversion reactions of CuF{sub 2}-MoO{sub 3} nanocomposite

    SciTech Connect

    Mansour, A.N.; Badway, F.; Yoon, W.-S.; Chung, K.Y.; Amatucci, G.G.

    2010-12-15

    We have used X-ray absorption spectroscopy at the Cu K-edge to investigate the electrochemical conversion reaction of 20 nm size 85 wt% CuF{sub 2}-15 wt% MoO{sub 3} nanocomposite under in situ conditions. The nanocomposite was prepared by high energy milling. Upon discharge, the lithiation reaction with the nanocomposite resulted in the formation of nanophase metallic Cu, which is consistent with the conversion of CuF{sub 2} into Cu and LiF. Based on XANES and Fourier transforms of EXAFS spectra, we show that the discharge process proceeded via the formation of highly dispersed Cu particles. Based on the coordination number of the first shell of Cu, the average size of the Cu particles was estimated to be in the 1-3 nm range in the fully discharged state. -- Graphical Abstract: Comparison of Fourier transform of in situ Cu K-edge EXAFS spectra for a fully discharged CuF{sub 2{center_dot}}MoO{sub 3} nanocomposite in a nonaqueous Li cell with that of a Cu foil. Quantitative analysis of the Fourier transforms confirmed that the discharge mechanism for the nanocomposite proceeds via the reaction CuF{sub 2}+2Li{yields}Cu+2LiF. The discharge product of Cu is in the form of highly dispersed nanoparticles. Display Omitted

  5. Facile synthesis of Cu{sub 2}O nanocube/polycarbazole composites and their high visible-light photocatalytic properties

    SciTech Connect

    Sun Wei; Sun Wendong; Zhuo Yujiang; Chu Ying

    2011-07-15

    Cu{sub 2}O nanocube/polycarbazole composites have been prepared by an one-pot solvothermal process using carbazole as a reductant. The polycarbazole layer not only protected and stabilized Cu{sub 2}O particles, but also prohibited the recombination of photogenerated electrons-holes pair and facilitated interfacial charge transfer between polycarbazole and Cu{sub 2}O. The composition, structure and morphology of the obtained products was systematically studied by X-ray powder diffraction (XRD), Field-emission scanning electron microscopy (FE-SEM), High-resolution transmission electron microscopy (HRTEM), Fourier transformation infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and UV-visible spectrophotometer. Furthermore, the visible-light photocatalytic behavior of the Cu{sub 2}O nanocube/polycarbazole composites on the methyl orange was investigated. - Graphical abstract: The uniform and monodisperse Cu{sub 2}O nanocube/polycarbazole composites were prepared by an one-pot solvothermal process. As covered by polycarbazole, the photocatalytic activities of Cu{sub 2}O nanocubes were improved. The polycarbazole not only protected and stabilized Cu{sub 2}O cubes, but also prohibited the recombination of photogenerated electrons-holes pair and facilitated interfacial charge transfer between polycarbazole and Cu{sub 2}O. Highlights: > The Cu{sub 2}O/polycarbazole nanocube composite has a better photocatalytic activity. > We obtained the composite by an one-pot solvothermal process. > Carbazole monomers as reductants.

  6. Highly-enhanced reflow characteristics of sputter deposited Cu alloy thin films for large scale integrated interconnections

    SciTech Connect

    Onishi, Takashi; Mizuno, Masao; Yoshikawa, Tetsuya; Munemasa, Jun; Mizuno, Masataka; Kihara, Teruo; Araki, Hideki; Shirai, Yasuharu

    2011-08-01

    An attempt to improve the reflow characteristics of sputtered Cu films was made by alloying the Cu with various elements. We selected Y, Sb, Nd, Sm, Gd, Dy, In, Sn, Mg, and P for the alloys, and ''the elasto-plastic deformation behavior at high temperature'' and ''the filling level of Cu into via holes'' were estimated for Cu films containing each of these elements. From the results, it was found that adding a small amount of Sb or Dy to the sputtered Cu was remarkably effective in improve the reflow characteristics. The microstructure and imperfections in the Cu films before and after high-temperature high-pressure annealing were investigated by secondary ion micrographs and positron annihilation spectroscopy. The results imply that the embedding or deformation mechanism is different for the Cu-Sb alloy films compared to the Cu-Dy alloy films. We consider that the former is embedded by softening or deformation of the Cu matrix, which has a polycrystalline structure, and the latter is embedded by grain boundary sliding.

  7. Atomic-scale investigation of interface-facilitated deformation twinning in severely deformed Ag-Cu nanolamellar composites

    SciTech Connect

    An, X. H. E-mail: xiaozhou.liao@sydenye.edu.au; Cao, Y.; Liao, X. Z. E-mail: xiaozhou.liao@sydenye.edu.au; Zhu, S. M.; Nie, J. F.; Kawasaki, M.; Ringer, S. P.; Langdon, T. G.; Zhu, Y. T.

    2015-07-06

    We report an atomic-scale investigation of interface-facilitated deformation twinning behaviour in Ag-Cu nanolamellar composites. Profuse twinning activities in Ag supply partial dislocations to directly transmit across the Ag-Cu lamellar interface that promotes deformation twinning in the neighbouring Cu lamellae although the interface is severely deformed. The trans-interface twin bands change the local structure at the interface. Our analysis suggests that the orientation relationship and interfacial structure between neighbouring Ag-Cu lamellae play a crucial role in such special interface-facilitated twinning behaviour.

  8. Effects of competing magnetic interactions on the electronic transport properties of CuCrSe{sub 2}

    SciTech Connect

    Tewari, Girish C.; Jawaharlal Nehru University, New Delhi 110067 ; Karppinen, Maarit; Rastogi, Ashok K.

    2013-02-15

    We have synthesized single-phase samples of the CuCrSe{sub 2} phase that exhibits hexagonal-rhombohedral layered crystal structure with space group R3m. Here we present a detailed study of electronic transport and magnetic properties of CuCrSe{sub 2}. We moreover investigate the heat capacity of CuCrSe{sub 2} in comparison to that of CuCrS{sub 2}. The electrical resistivity of CuCrSe{sub 2} shows metallic-like behavior down to 2 K, while the thermoelectric power is large around 100 {mu}V K{sup -1} at 300 K. A weak anomaly in resistivity and a rounded maximum in magnetic susceptibility are observed around 55 K. No sharp transition at 55 K is observed in the heat capacity of CuCrSe{sub 2}, rather a visible maximum is seen. At low temperatures from 2 to 14 K, the magnetic heat capacity follows T{sup 2}-dependence. We tentatively believe this behavior of CuCrSe{sub 2} to be due to competing magnetic interactions between intralayer Cr atoms. The ferromagnetic Cr-Se-Cr indirect exchange among intralayer Cr atoms is enhanced in the selenide compound (that is more metallic than the sulfide compound), and competes with the antiferromagnetic Cr-Cr direct interactions. The interlayer antiferromagnetic exchange through Cu atoms leads to magnetic ordering at low temperature at T{sub N}=55 K. - Graphical abstract: Comparison of magnetic properties of CuCrSe{sub 2} and CuCrS{sub 2} indicates a sharp cusp-like anomaly in magnetic susceptibility at the antiferromagnetic transition of CuCrS{sub 2} while the maximum of CuCrSe{sub 2} is well rounded. Magnetization is reversible after field-cooling (FC) and zero-field-cooling (ZFC) for both compounds. Highlights: Black-Right-Pointing-Pointer Layered CuCrSe{sub 2} can be synthesized in both fully and partially cation-ordered forms. Black-Right-Pointing-Pointer Contrary to previously believed insulating nature the cation-ordered phase is metallic. Black-Right-Pointing-Pointer Magnetic property of CuCrSe{sub 2} is somewhat different from

  9. Improved electrochemical performances of CuO nanotube array prepared via electrodeposition as anode for lithium ion battery

    SciTech Connect

    Xiao, Anguo Zhou, Shibiao; Zuo, Chenggang; Zhuan, Yongbing; Ding, Xiang

    2015-10-15

    Graphical abstract: CuO nanotube array electrodes prepared by electrodeposition method exhibit an excellent lithium ion storage ability as anode of Li-ion battery. - Highlights: • CuO nanotube arrays are synthesized by an electrodeposition method. • CuO nanotube shows a high-rate performance. • CuO nanotube shows an excellent cycling performance. - Abstract: We report a facile strategy to prepared CuO nanotube arrays directly grown on Cu plate through the electrodeposition method. The as-prepared CuO nanotubes show a quasi-cylinder nanostructure with internal diameters of ca. ∼100 nm, external diameters of ca. ∼120 nm, and average length of ∼3 μm. As an anode for lithium ion batteries, the electrochemical properties of the CuO nanotube arrays are investigated by cyclic voltammetry (CV) and galvanostatic charge/discharge tests. Due to the unique nanotube nanostructure, the as-prepared CuO electrodes exhibit good rate performance (550 mAh g{sup −1} at 0.1 C and 464 mAh g{sup −1} at 1 C) and cycling performance (581 mAh g{sup −1} at 0.1 C and 538 mAh g{sup −1} at 0.5 C)

  10. Kondo effect in Co{sub x}Cu{sub 1-x} granular alloys prepared by chemical

    Office of Scientific and Technical Information (OSTI)

    reduction method (Journal Article) | SciTech Connect Kondo effect in Co{sub x}Cu{sub 1-x} granular alloys prepared by chemical reduction method Citation Details In-Document Search Title: Kondo effect in Co{sub x}Cu{sub 1-x} granular alloys prepared by chemical reduction method Nanostructured CoCu granular alloys Co{sub x}Cu{sub 1-x} (x ≤ 0.3) have been prepared by chemical reduction method using NaBH{sub 4} as a reducing agent. Electronic transport properties are studied in the temperature

  11. Ab initio investigation on hydrogen adsorption capability in Zn and Cu-based metal organic frameworks

    SciTech Connect

    Tanuwijaya, V. V.; Hidayat, N. N. Agusta, M. K. Dipojono, H. K.

    2015-09-30

    One of the biggest challenge in material technology for hydrogen storage application is to increase hydrogen uptake in room temperature and pressure. As a class of highly porous material, Metal-Organic Frameworks (MOF) holds great potential with its tunable structure. However, little is known about the effect of metal cluster to its hydrogen storage capability. Investigation on this matter has been carried out carefully on small cluster of Zn and Cu-based MOF using first principles method. The calculation of two distinct building units of MOFs, namely octahedral and paddle-wheel models, have been done with B3LYP density functional method using 6-31G(d,p) and LANL2DZ basis sets. From geometry optimization of Zn-based MOF linked by benzene-dicarboxylate (MOF-5), it is found that hydrogen tends to keep distance from metal cluster group and stays above benzene ring. In the other hand, hydrogen molecule prefers to stay atop of the exposed Cu atom in Cu-based MOF system linked by the same linker group (Cu-bdc). Calculated hydrogen binding enthalpies for Zn and Cu octahedral cages at ZnO{sub 3} sites are 1.64kJ/mol and 2.73kJ/mol respectively, while hydrogen binding enthalpies for Zn and Cu paddle-wheel cages calculated on top of metal atoms are found to be at 6.05kJ/mol and 6.10kJ/mol respectively. Major difference between Zn-MOF-5 and Cu-bdc hydrogen uptake performance might be caused by unsaturated metal sites present in Cu-bdc system and the influence of their geometric structures, although a small difference on binding energy in the type of transition metal used is also observed. The comparison between Zn and Cu-based MOF may contribute to a comprehensive understanding of metal clusters and the importance of selecting best transition metal for design and synthesis of metal-organic frameworks.

  12. Morphology, electrical, and optical properties of heavily doped ZnTe:Cu thin films

    SciTech Connect

    El Akkad, Fikry; Abdulraheem, Yaser

    2013-11-14

    We report on a study of the physical properties of ZnTe:Cu films with Cu content up to ∼12 at. % prepared using rf magnetron sputtering. The composition and lateral homogeneities are studied using X-ray photoelectron spectroscopy (XPS). Atomic force microscopy measurements on films deposited at different substrate temperatures (up to 325 °C) yielded activation energy of 12 kJ/mole for the grains growth. The results of XPS and electrical and optical measurements provide evidence for the formation of the ternary zinc copper telluride alloy in films containing Cu concentration above ∼4 at. %. The XPS results suggest that copper is incorporated in the alloy with oxidation state Cu{sup 1+} so that the alloy formula can be written Zn{sub 1−y}Cu{sub y} Te with y = 2−x, where x is a parameter measuring the stoichiometry in the Cu site. The formation of this alloy causes appreciable shift in the binding energies of the XPS peaks besides an IR shift in the energy band gap. Detailed analysis of the optical absorption data revealed the presence of two additional transitions, besides the band gap one, originating from the Γ{sub 8} and Γ{sub 7} (spin-orbit) valence bands to a donor level at ∼0.34 eV below the Γ{sub 6} conduction band. This interpretation yields a value for the valence band splitting energy Δ≅ 0.87 eV independent of copper concentration. On the other hand, the mechanism of formation of the alloy is tentatively explained in terms of a point defect reaction in which substitutional Cu defect Cu{sub Zn} is also created. Assuming that substitutional Cu is the dominant acceptor in the Zn rich alloy as in ZnTe, its formation energy was determined to be 1.7 eV close to the theoretical value (1.41 eV) in ZnTe.

  13. Exponentially decaying magnetic coupling in sputtered thin film FeNi/Cu/FeCo trilayers

    SciTech Connect

    Wei, Yajun Akansel, Serkan; Thersleff, Thomas; Brucas, Rimantas; Lansaker, Pia; Leifer, Klaus; Svedlindh, Peter; Harward, Ian; Celinski, Zbigniew; Ranjbar, Mojtaba; Dumas, Randy K.; Jana, Somnath; Pogoryelov, Yevgen; Karis, Olof; Åkerman, Johan

    2015-01-26

    Magnetic coupling in trilayer films of FeNi/Cu/FeCo deposited on Si/SiO{sub 2} substrates have been studied. While the thicknesses of the FeNi and FeCo layers were kept constant at 100 Å, the thickness of the Cu spacer was varied from 5 to 50 Å. Both hysteresis loop and ferromagnetic resonance results indicate that all films are ferromagnetically coupled. Micromagnetic simulations well reproduce the ferromagnetic resonance mode positions measured by experiments, enabling the extraction of the coupling constants. Films with a thin Cu spacer are found to be strongly coupled, with an effective coupling constant of 3 erg/cm{sup 2} for the sample with a 5 Å Cu spacer. The strong coupling strength is qualitatively understood within the framework of a combined effect of Ruderman-Kittel-Kasuya-Yosida and pinhole coupling, which is evidenced by transmission electron microscopy analysis. The magnetic coupling constant surprisingly decreases exponentially with increasing Cu spacer thickness, without showing an oscillatory thickness dependence. This is partially connected to the substantial interfacial roughness that washes away the oscillation. The results have implications on the design of multilayers for spintronic applications.

  14. Luminescence properties of monoclinic Cu{sub 4}I{sub 4}(Piperidine){sub 4}

    SciTech Connect

    Jalilian, Ehsan; Liao, Rong-Zhen; Himo, Fahmi; Lidin, Sven

    2011-08-15

    Highlights: {yields} A new modification of Cu{sub 4}I{sub 4}Pip{sub 4} has been produced under hydrothermal conditions. {yields} This modification have fluorescence properties when it is exposed to UV light. {yields} The fluorescence properties was characterized with fluorescence spectrophotometer. {yields} Quantum mechanical calculations was also performed. -- Abstract: A new modification of Cu{sub 4}I{sub 4}Pip{sub 4} has been synthesized under hydrothermal conditions. X-ray crystallography revealed that this compound crystallized in the monoclinic system and consists of a tetrahedral core with composition Cu{sub 4}I{sub 4}, in which each Cu atom is coordinated by a piperidine molecule via the N atom. In contrast to a previously reported modification of Cu{sub 4}I{sub 4}Pip{sub 4}, the present modification shows luminescent properties when exposed to UV-light. In addition, we have used time-dependent density functional theory calculations to characterize both compounds in term of both absorption and emission.

  15. Influence of lattice orientation on growth and structure of graphene on Cu(001)

    SciTech Connect

    Wofford, Joseph M.; Nie, Shu; Thrmer, Konrad; McCarty, Kevin F.; Dubon, Oscar D.

    2015-03-31

    We have used low-energy electron microscopy (LEEM) and diffraction (LEED) to examine the significance of lattice orientation in graphene growth on Cu(0 0 1). Individual graphene domains undergo anisotropic growth on the Cu surface, and develop into lens shapes with their long axes roughly aligned with Cu <1 0 0> in-plane directions. Furthermore, the long axis of a lens-shaped domain is only rarely oriented along a C <1 1> direction, suggesting that carbon attachment at zigzag graphene island edges is unfavorable. A kink-mediated adatom attachment process is consistent with the behavior observed here and reported in the literature. Likewise, the details of the ridged moir pattern formed by the superposition of the graphene lattice on the (0 0 1) Cu surface also evolve with the graphene lattice orientation, and are predicted well by a simple geometric model. Managing the kink-mediated growth mode of graphene on Cu(0 0 1) will be necessary for the continued improvement of this graphene synthesis technique.

  16. Kondo-lattice formation in cubic-phase YbCu{sub 5}

    SciTech Connect

    Tsujii, N.; He, J.; Amita, F.; Yoshimura, K.; Kosuge, K.; Michor, H.; Hilscher, G.; Goto, T.

    1997-10-01

    The YbCu{sub 5} phase with C15b structure has been prepared by a high-pressure technique, and its physical properties have been investigated. The temperature dependence of magnetic susceptibility, electrical resistivity, and specific heat show Kondo-lattice formation. Furthermore, a heavy Fermi-liquid state without magnetic ordering down to 2.0 K is found to evolve below about 6 K. The electronic specific heat coefficient {gamma} is enhanced to values as large as to 550 mJ/molthinspK{sup 2}. The magnetization measured up to 40 T at 1.6 K has a field dependence which is expected for a Kondo system when the total angular momentum is J{gt}1. All results are in good agreement with the extrapolation of the previous results of YbCu{sub 5{minus}x}Ag{sub x} (0.125{le}x{le}1.0) for x{r_arrow}0. The concentration dependence of characteristic temperatures of YbCu{sub 5{minus}x}Ag{sub x} can be quantitatively explained by the chemical pressure effect within the compressible Kondo model for the full range of Ag concentration ( 0.0{le}x{le}1.0). The origins of Kondo-lattice formation in YbCu{sub 4}Ag and the valence transition in YbCu{sub 4}In are discussed. {copyright} {ital 1997} {ital The American Physical Society}

  17. Energetics of the formation of CuAg coreshell nanoparticles

    DOE PAGES [OSTI]

    Chandross, Michael

    2014-10-06

    Our work presents molecular dynamics and Monte Carlo simulations aimed at developing an understanding of the formation of coreshell CuAg nanoparticles. The effects of surface and interfacial energies were considered and used to form a phenomenological model that calculates the energy gained upon the formation of a coreshell structure from two previously distinct, non-interacting nanoparticles. In most cases, the coreshell structure was found to be energetically favored. Specifically, the difference in energy as a function of the radii of the individual Cu and Ag particles was examined, with the assumption that a coreshell structure forms. In general, it was foundmorethat the energetic gain from forming such a structure increased with increasing size of the initial Ag particle. This result was interpreted as a result of the reduction in surface energy. Moreover, for two separate particles, both Cu and Ag contribute to the surface energy; however, for a coreshell structure, the only contribution to the surface energy is from the Ag shell and the Cu contribution is changed to a CuAg interfacial energy, which is always smaller.less

  18. Enhanced irreversibility by crystal defects in the Bi-Sr-Ca-Cu-O system

    SciTech Connect

    Salem-Sugui, S. Jr.; Shi, Donglu; McFarland, S.E.

    1991-04-01

    We measured magnetic irreversibility, H*(T), in liquid-quenched Bi-Sr-Ca-Cu-O samples with various microstructures at high applied field (up to 7 T). We found that H*(T) is considerably increased in the Bi{sub 2}Sr{sub 2}Ca{sub 3}Cu{sub 4}O{sub x} (2234) sample with a large amount of crystal defects, including severe lattice distortion and calcium and copper rich precipitates. We argue that the lattice distortion may affect the degree of anisotropy and the Josephson coupling between the Cu-O layers, which in turn enhance the irreversibility in the Bi-Sr-Ca-Cu-O system. A critical current density, J{sub c}, of 8 {times} 10{sup 4} A/cm{sup 2} at 8 kG and 40 K was obtained in the 2234 sample with many defects, while the J{sub c} dropped significantly at the same temperature and field in the near stoichiometry Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (2223) sample with a uniform microstructure.

  19. Theoretical calculation of the melting curve of Cu-Zr binary alloys

    SciTech Connect

    Gunawardana, K. G.S.H.; Wilson, S. R.; Mendelev, M. I.; Song, Xueyu

    2014-11-14

    Helmholtz free energies of the dominant binary crystalline solids found in the Cu-Zr system at high temperatures close to the melting curve are calculated. This theoretical approach combines fundamental measure density functional theory (applied to the hard-sphere reference system) and a perturbative approach to include the attractive interactions. The studied crystalline solids are Cu(fcc), Cu51Zr14(β), CuZr(B2), CuZr2(C11b), Zr(hcp), and Zr(bcc). The calculated Helmholtz free energies of crystalline solids are in good agreement with results from molecular-dynamics (MD) simulations. Using the same perturbation approach, the liquid phase free energies are calculated as a function of composition and temperature, from which the melting curve of the entire composition range of this system can be obtained. Phase diagrams are determined in this way for two leading embedded atom method potentials, and the results are compared with experimental data. Furthermore, theoretical melting temperatures are compared both with experimental values and with values obtained directly from MD simulations at several compositions.

  20. Theoretical calculation of the melting curve of Cu-Zr binary alloys

    DOE PAGES [OSTI]

    Gunawardana, K. G.S.H.; Wilson, S. R.; Mendelev, M. I.; Song, Xueyu

    2014-11-14

    Helmholtz free energies of the dominant binary crystalline solids found in the Cu-Zr system at high temperatures close to the melting curve are calculated. This theoretical approach combines fundamental measure density functional theory (applied to the hard-sphere reference system) and a perturbative approach to include the attractive interactions. The studied crystalline solids are Cu(fcc), Cu51Zr14(β), CuZr(B2), CuZr2(C11b), Zr(hcp), and Zr(bcc). The calculated Helmholtz free energies of crystalline solids are in good agreement with results from molecular-dynamics (MD) simulations. Using the same perturbation approach, the liquid phase free energies are calculated as a function of composition and temperature, from which themore » melting curve of the entire composition range of this system can be obtained. Phase diagrams are determined in this way for two leading embedded atom method potentials, and the results are compared with experimental data. Furthermore, theoretical melting temperatures are compared both with experimental values and with values obtained directly from MD simulations at several compositions.« less

  1. Structure and Bonding of Tungsten Oxide Clusters on Nanostructured Cu-O Surfaces

    SciTech Connect

    Wagner, Margareta; Surnev, Svetlozar; Ramsey, Michael; Barcaro, Giovanni; Sementa, Luca; Negreiros, Fabio R.; Fortunelli, Alessandro; Dohnalek, Zdenek; Netzer, Falko P.

    2011-12-01

    (WO3)3 gas-phase clusters generated via vacuum sublimation are deposited under UHV and low temperature (5 K) conditions on a Cu(110) 'stripe' phase consisting of alternating Cu-O (2x1) and clean Cu regions. STM imaging shows that the clusters adsorb as intact units on both substrates, and the suggested adsorption geometries are confirmed by density-functional (DF) simulations. On the clean surface the overall distortion is minor and we are able to image the nodal structure of an individual molecular orbital in the STM at low bias, whereas on the Cu-O surface both the clusters and the substrate are significantly distorted, due to the strong oxygen affinity of W atoms. On both surfaces cluster and Cu electronic states are appreciably mixed, and electron charge is donated by the surface to the cluster. The experimentally STS-determined DOS signature of the adsorption complex consists in two peaks across the Fermi energy and is well reproduced by the DF calculations.

  2. Studies on the thermal stability of BiCuSeO

    SciTech Connect

    Barreteau, Celine; Berardan, David Dragoe, Nita

    2015-02-15

    BiCuSeO based materials have been reported as very promising thermoelectric materials, with thermoelectric figure of merit values that make them among the best p-type Pb-free polycrystalline thermoelectric materials, and they could be suitable for applications in thermal to electrical power conversion modules in a 300–650 °C temperature range. In this paper, we report on the phase stability and thermal stability of these materials under inert and oxidizing atmosphere and we discuss their actual potential for wide scale applications. We show that although they are stable in inert atmosphere up to 650 °C, with very slow volatilization rate, it is not the case under oxidizing atmosphere, with a quick oxidation starting at a moderate temperature. - Graphical abstract: BiCuSeO oxidation under air, starting below 300 °C. - Highlights: • Decomposition and oxidation mechanisms of BiCuSeO were studied. • BiCuSeO does not volatilize in inert atmosphere up to 650 °C. • BiCuSeO starts oxidizing for temperatures as low as 200 °C.

  3. Impact of sulfation and desulfation on NOx reduction using Cu-chabazite SCR catalysts

    DOE PAGES [OSTI]

    Brookshear, Daniel William; Nam, Jeong -Gil; Nguyen, Ke; Toops, Todd J.; Binder, Andrew J.

    2015-06-05

    This bench reactor study investigates the impact of gaseous sulfur on the NOx reduction activity of Cu-chabazite SCR (Cu-CHA) catalysts at SO2 concentrations representative of marine diesel engine exhaust. After two hours of 500 ppm SO2 exposure at 250 and 400 °C in the simulated diesel exhaust gases, the NOx reduction activity of the sulfated Cu-CHA SCR catalysts is severely degraded at evaluation temperatures below 250 °C; however, above 250 °C the impact of sulfur exposure is minimal. EPMA shows that sulfur is located throughout the washcoat and along the entire length of the sulfated samples. Interestingly, BET measurements revealmore » that the sulfated samples have a 20% decrease in surface area. Moreover, the sulfated samples show a decrease in NOx/nitrate absorption during NO exposure in a DRIFTS reactor which suggests that Cu sites in the catalyst are blocked by the presence of sulfur. SO2 exposure also results in an increase in NH3 storage capacity, possibly due to the formation of ammonium sulfate species in the sulfated samples. In all cases, lean thermal treatments as low as 500 °C reverse the effects of sulfur exposure and restore the NOx reduction activity of the Cu-CHA catalyst to that of the fresh condition.« less

  4. Impact of Sulfation and Desulfation on NOx Reduction Using Cu-Chabazite SCR Catalysts

    SciTech Connect

    Brookshear, Daniel W; Nam, Jeong-Gil; Nguyen, Ke; Toops, Todd J; Binder, Andrew J

    2015-01-01

    This bench reactor study investigates the impact of gaseous sulfur on the NOx reduction activity of Cu-chabazite SCR (Cu-CHA) catalysts at SO2 concentrations representative of marine diesel engine exhaust. After two hours of 500 ppm SO2 exposure at 250 and 400 C in the simulated diesel exhaust gases, the NOx reduction activity of the sulfated Cu-CHA SCR catalysts is severely degraded at evaluation temperatures below 250 C; however, above 250 C the impact of sulfur exposure is minimal. EPMA shows that sulfur is located throughout the washcoat and along the entire length of the sulfated samples. Interestingly, BET measurements reveal that the sulfated samples have a 20% decrease in surface area. Furthermore, the sulfated samples show a decrease in NOx/nitrate absorption during NO exposure in a DRIFTS reactor which suggests that Cu sites in the catalyst are blocked by the presence of sulfur. SO2 exposure also results in an increase in NH3 storage capacity, possibly due to the formation of ammonium sulfate species in the sulfated samples. In all cases, lean thermal treatments as low as 500 C reverse the effects of sulfur exposure and restore the NOx reduction activity of the Cu-CHA catalyst to that of the fresh condition.

  5. Significant enhancement of the strength-to-resistivity ratio by using nanotwins in epitaxial Cu films

    SciTech Connect

    Misra, Amit; Ronningh, Filip; Anderoglu, Osman; Zhang, X

    2008-01-01

    Epitaxial nanotwinned Cu films, with an average twin spacing ranging from 7 to 16 nm, exhibit a high ratio of strength-to-electrical resisitivity, -400 MPa({mu}{Omega}cm){sup -1}. The hardness of these Cu films approaches 2.8 GPa, and their electrical resistivities are comparable to that of oxygen-free high-conductivity Cu. Compared to high-angle grain boundaries, coherent twin interfaces possess inherently high resistance to the transmission of single dislocations, and yet an order of magnitude lower electron scattering coefficient, determined to be 1.5-5 x 10{sup -7} {mu}{Omega}cm{sup 2} at room temperature. Analytical studies as well as experimental results show that, in polycrystalline Cu, grain refinement leads to a maximum of the strength-to-resistivity ratio, -250 MPa({mu}{Omega}cm){sup -1}, when grain size is comparable to the mean-free path of electrons. However, in twinned Cu, such a ratio increases continuously with decreasing twin spacing down to a few nanometers. Hence nanoscale growth twins are more effective to achieve a higher strength-to-resistivity ratio than high-angle grain boundaries.

  6. Density functional study of CaN mono and bilayer on Cu(001)

    SciTech Connect

    Zahedifar, Maedeh; Hashemifar, S. Javad Akbarzadeh, Hadi

    2014-01-15

    Density functional - pseudopotential calculations are performed to provide first-principles insights into magnetic behaviour of bulk CaN and CaN monolayers on Cu(001) in the rock-salt (RS) and zinc-blende (ZB) structures. Our results indicate that both RS- and ZB-CaN exhibit half-metallic ferromagnetism originated from the incomplete 2p shell of the nitrogen ion. In contrast to the bulk CaN, the CaN monolayers on Cu(001) generally favor ZB structure. We argue that the more stable ZB-CaN thin films on Cu(001) are nonmagnetic, because of strong Cu-N bonding at the interface, while the less stable Ca terminated ZB-CaN thin films exhibit half-metallic ferromagnetism. The transition path between the high energy ferromagnetic and the stable nonmagnetic configurations of the ZB-CaN monolayer on Cu(001) are studied by using the nudged elastic band method. We observe a two stages transition and an activation barrier of about 1.18 eV in the minimum energy path of this transition.

  7. Influence of lattice orientation on growth and structure of graphene on Cu(001)

    DOE PAGES [OSTI]

    Wofford, Joseph M.; Nie, Shu; Thürmer, Konrad; McCarty, Kevin F.; Dubon, Oscar D.

    2015-03-31

    We have used low-energy electron microscopy (LEEM) and diffraction (LEED) to examine the significance of lattice orientation in graphene growth on Cu(0 0 1). Individual graphene domains undergo anisotropic growth on the Cu surface, and develop into lens shapes with their long axes roughly aligned with Cu <1 0 0> in-plane directions. Furthermore, the long axis of a lens-shaped domain is only rarely oriented along a C <1 1> direction, suggesting that carbon attachment at “zigzag” graphene island edges is unfavorable. A kink-mediated adatom attachment process is consistent with the behavior observed here and reported in the literature. Likewise, themore » details of the ridged moiré pattern formed by the superposition of the graphene lattice on the (0 0 1) Cu surface also evolve with the graphene lattice orientation, and are predicted well by a simple geometric model. Managing the kink-mediated growth mode of graphene on Cu(0 0 1) will be necessary for the continued improvement of this graphene synthesis technique.« less

  8. Effect of Na-doped Mo on Selenization Pathways for CuGa/In Metallic Precursors

    SciTech Connect

    Krishnan, Rangarajan; Tong, Gabriel; Kim, Woo Kyoung; Payzant, E Andrew; Adelhelm, Christoph; Franzke, Enrico; Winkler, Jörg; Anderson, Timothy J

    2013-01-01

    Reaction pathways were followed for selenization of CuGa/In precursor structures using in-situ high temperature X-ray diffraction (HTXRD). Precursor films were deposited on Na-free and Na-doped Mo (3 and 5 at %)/Na-free glass. The precursor film was constituted with CuIn, In, Cu9Ga4, Cu3Ga, Cu16In9 and Mo. HTXRD measurements during temperature ramp selenization showed CIS formation occurs first, followed by CGS formation, and then mixing on the group III sub-lattice to form CIGS. CIGS formation was observed to be complete at ~450 C for samples deposited on 5 at % Na-doped Mo substrates. MoSe2 formation was evidenced after the CIGS synthesis reaction was complete. The Ga distribution in the annealed CIGS was determined by Rietveld refinement. Isothermal reaction studies were conducted for CIGS (112) formation in the temperature range 260-320 C to estimate the rate constants.

  9. A reactive magnetron sputtering route for attaining a controlled core-rim phase partitioning in Cu{sub 2}O/CuO thin films with resistive switching potential

    SciTech Connect

    Ogwu, A. A.; Darma, T. H.

    2013-05-14

    The achievement of a reproducible and controlled deposition of partitioned Cu{sub 2}O/CuO thin films by techniques compatible with ULSI processing like reactive magnetron sputtering has been reported as an outstanding challenge in the literature. This phase partitioning underlies their performance as reversible resistive memory switching devices in advanced microelectronic applications of the future. They are currently fabricated by thermal oxidation and chemical methods. We have used a combination of an understanding from plasma chemistry, thermo-kinetics of ions, and rf power variation during deposition to successfully identify a processing window for preparing partitioned Cu{sub 2}O/CuO films. The production of a core rich Cu{sub 2}O and surface rich Cu{sub 2}O/CuO mixture necessary for oxygen migration during resistive switching is confirmed by XRD peaks, Fourier transform infra red Cu (I)-O vibrational modes, XPS Cu 2P{sub 3/2} and O 1S peak fitting, and a comparison of satellite peak ratio's in Cu 2P{sub 3/2} fitted peaks. We are proposing based on the findings reported in this paper that an XPS satellite peak intensity(I{sub s}) to main peak intensity ratio (I{sub m}) {<=} 0.45 as an indicator of a core rich Cu{sub 2}O and surface rich Cu{sub 2}O/CuO formation in our prepared films. CuO is solely responsible for the satellite peaks. This is explained on the basis that plasma dissociation of oxygen will be limited to the predominant formation of Cu{sub 2}O under certain plasma deposition conditions we have identified in this paper, which also results in a core-rim phase partitioning. The deposited films also followed a Volmer-Weber columnar growth mode, which could facilitate oxygen vacancy migration and conductive filaments at the columnar interfaces. This is further confirmed by optical transmittance and band-gap measurements using spectrophotometry. This development is expected to impact on the early adoption of copper oxide based resistive memory

  10. Low-cost CuInSe[sub 2] submodule development

    SciTech Connect

    Basol, B.M.; Kapur, V.K.; Halani, A.; Leidholm, C. )

    1992-10-01

    Aim of this project is development and demonstration of processing steps necessary for fabrication of high efficiency CuInSe[sub 2] solar cells and sub-modules by the two-stage technique (also called the selenization method.) During this period, we have optimized the processing parameters of this method and demonstrated CuInSe[sub 2]/CdS/ZnO devices with a 1[endash]4 cm[sup 2] area and up to 12.4% active area efficiency. We have also developed a novel approach for the preparation of Cu/In precursors that improved the stoichiometric and morphological uniformity in these films. We have developed processing steps and tooling for handling up to 1 ft[sup 2] size substrates and as a result of these efforts demonstrated our first monolithically integrated sub-module of 1 ft[sup 2] area. 16 figs, 1 tab, 15 refs.

  11. Role of polycrystallinity in CdTe and CuInSe sub 2 photovoltaic cells

    SciTech Connect

    Sites, J.R. )

    1991-01-01

    The polycrystalline nature of thin-film CdTe and CuInSe{sub 2} solar cells continues to be a major factor in several individual losses that limit overall cell efficiency. This report describes progress in the quantitative separation of these losses, including both measurement and analysis procedures. It also applies these techniques to several individual cells to help document the overall progress with CdTe and CuInSe{sub 2} cells. Notably, CdTe cells from Photon Energy have reduced window photocurrent losses to 1 mA/Cm{sup 2}; those from the University of South Florida have achieved a maximum power voltage of 693 mV; and CuInSe{sub 2} cells from International Solar Electric Technology have shown a hole density as high as 7 {times} 10{sup 16} cm{sup {minus}3}, implying a significant reduction in compensation. 9 refs.

  12. Melt-processing of Y-Ba-Cu-O superconductors for improved levitation

    SciTech Connect

    Balachandran, U.; Zhong, W.; Emerson, J.E.; McDaniel, R.L.

    1994-04-01

    Melt processed bulk YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) superconductors are of considerable interest in the application of low-friction, superconducting permanent magnet bearings and flywheel-energy-storage devices. The mechanisms of enhanced flux pinning in the melt processed samples has been the subject of many investigations. Fine precipitates of Y{sub 2}BaCuO{sub 5} (211) are considered potential flux-pinning sites by many investigators. Several groups have reported the refinement of 211 precipitates through Pt additions. In this paper, the authors describe the melt processing of YBCO with additives such as 211, Pt, and Ag. Large single domain regions are obtained using small SmBa2Cu3O{sub 7{minus}{delta}} (Sm-123) single crystal seeds. The microstructure and levitation forces are measured and reported here.

  13. Efficient organic solar cells using copper(I) iodide (CuI) hole transport layers

    SciTech Connect

    Peng, Ying; Yaacobi-Gross, Nir; Perumal, Ajay K.; Faber, Hendrik A.; Bradley, Donal D. C.; Anthopoulos, Thomas D. E-mail: t.anthopoulos@imperial.ac.uk; Vourlias, George; Patsalas, Panos A.; He, Zhiqun E-mail: t.anthopoulos@imperial.ac.uk

    2015-06-15

    We report the fabrication of high power conversion efficiency (PCE) polymer/fullerene bulk heterojunction (BHJ) photovoltaic cells using solution-processed Copper (I) Iodide (CuI) as hole transport layer (HTL). Our devices exhibit a PCE value of ∼5.5% which is equivalent to that obtained for control devices based on the commonly used conductive polymer poly(3,4-ethylenedioxythiophene): polystyrenesulfonate as HTL. Inverted cells with PCE >3% were also demonstrated using solution-processed metal oxide electron transport layers, with a CuI HTL evaporated on top of the BHJ. The high optical transparency and suitable energetics of CuI make it attractive for application in a range of inexpensive large-area optoelectronic devices.

  14. Stable n-CuInSe/sub 2/iodide-iodine photoelectrochemical cell

    DOEpatents

    Cahen, D.; Chen, Y.W.

    1984-09-20

    In a photoelectrochemical solar cell, stable output and solar efficiency in excess of 10% are achieved with a photoanode of n-CuInSe/sub 2/ electrode material and an iodine/iodide redox couple used in a liquid electrolyte. The photoanode is prepared by treating the electrode material by chemical etching, for example in Br/sub 2//MeOH; heating the etched electrode material in air or oxygen; depositing a surface film coating of indium on the electrode material after the initial heating; and thereafter again heating the electrode material in air or oxygen to oxidize the indium. The electrolyte is treated by the addition of Cu/sup +/ or Cu/sup 2 +/ salts and in In/sup 3 +/ salts.

  15. Stable N-CuInSe.sub.2 /iodide-iodine photoelectrochemical cell

    DOEpatents

    Cahen, David; Chen, Yih W.

    1985-01-01

    In a photoelectrochemical solar cell, stable output and solar efficiency in excess of 10% are achieved with a photoanode of n-CuInSe.sub.2 electrode material and an iodine/iodide redox couple used in a liquid electrolyte. The photoanode is prepared by treating the electrode material by chemical etching, for example in Br.sub.2 /MeOH; heating the etched electrode material in air or oxygen; depositing a surface film coating of indium on the electrode material after the initial heating; and thereafter again heating the electrode material in air or oxygen to oxidize the indium. The electrolyte is treated by the addition of Cu.sup.+ or Cu.sup.2+ salts and In.sup.3+ salts.

  16. Interpretation of thermoelectric properties of Cu substituted LaCoO{sub 3} ceramics

    SciTech Connect

    Choudhary, K. K.; Kaurav, N.; Sharma, U.; Ghosh, S. K.

    2014-04-24

    The thermoelectric properties of LaCo{sub 1−x}Cu{sub x}O{sub 3−δ} is theoretically analyzed, it is observed that thermoelectric figure of merit ZT (=S{sup 2}σT/κ) is maximized by Cu substitution in LaCoO{sub 3} Ceramics at x=0.15. The lattice thermal conductivity and thermoelectric power were estimated by the scattering of phonons with defects, grain boundaries, electrons and phonons to evaluate the thermoelectric properties. We found that Cu substitution increase the phonon scattering with grain boundaries and defects which significantly increase the thermoelectric power and decrease the thermal conductivity. The present numerical analysis will help in designing more efficient thermoelectric materials.

  17. Enhanced spin Hall effect by electron correlations in CuBi alloys

    SciTech Connect

    Gu, Bo Xu, Zhuo; Mori, Michiyasu; Maekawa, Sadamichi; Ziman, Timothy

    2015-05-07

    A recent experiment in CuBi alloys obtained a large spin Hall angle (SHA) of −0.24 (Niimi et al., Phys. Rev. Lett. 109, 156602 (2012)). We find that the SHA can be dramatically enhanced by Bi impurities close to the Cu surface. The mechanisms of this enhancement are two-fold. One is that the localized impurity state on surface has a decreased hybridization and combined with Coulomb correlation effect. The other comes from the low-dimensional state of conduction electrons on surface, which results in a further enhancement of skew scattering by impurities. Furthermore, we note that a discrepancy in sign of SHA between the experiment and previous theories is simply caused by different definitions of SHA. This re-establishes skew scattering as the essential mechanism underlying the spin Hall effect in CuBi alloys.

  18. Optical and quantum efficiency analysis of (Ag,Cu)(In,Ga)Se2 absorber layers

    SciTech Connect

    Boyle, Jonathan; Hanket, Gregory; Shafarman, William

    2009-06-09

    (Ag,Cu)(In,Ga)Se2 thin films have been deposited by elemental co-evaporation over a wide range of compositions and their optical properties characterized by transmission and reflection measurements and by relative shift analysis of quantum efficiency device measurements. The optical bandgaps were determined by performing linear fits of (?h?)2 vs. h?, and the quantum efficiency bandgaps were determined by relative shift analysis of device curves with fixed Ga/(In+Ga) composition, but varying Ag/(Cu+Ag) composition. The determined experimental optical bandgap ranges of the Ga/(In+Ga) = 0.31, 0.52, and 0.82 groups, with Ag/(Cu+Ag) ranging from 0 to 1, were 1.19-1.45 eV, 1.32-1.56 eV, and 1.52-1.76 eV, respectively. The optical bowing parameter of the different Ga/(In+Ga) groups was also determined.

  19. Structural and magnetic phase transitions in CeCu6-xTx (T = Ag,Pd)

    DOE PAGES [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.; et al

    2015-12-15

    The structural and the magnetic properties of CeCu6-xAgx (0 ≤ x ≤ 0.85) and CeCu6-xPdx (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 CeCu6-xAgx and CeCu6-xPdx as a function of Ag/Pd composition are reported. The end member, CeCu6, undergoes a structural phase transition from an orthorhombic (Pnma) to a monoclinic (P21/c) phase at 240 K. In CeCu6-xAgx, the structural phase transition temperature (Ts) decreases linearly with Ag concentration and extrapolates to zero at xS ≈ 0.1. The structural transitionmore » in CeCu6-xPdx 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, CeCu6-xAgx and CeCu6-xPdx, 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 (δ1 0 δ2), where δ1 ~ 0.62, δ2 ~ 0.25, x = 0.125 for CeCu6-xPdx and δ1 ~ 0.64, δ2 ~ 0.3, x = 0.3 for CeCu6-xAgx. 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.« less

  20. Effect of cooling rate on the microstructure and microhardness of the CuZrAgAl alloy

    SciTech Connect

    Liu, Y.; Blandin, J.J.; Suery, M.; Kapelski, G.

    2012-08-15

    The effect of cooling rate on the microstructure and microhardness of the Cu{sub 40}Zr{sub 44}Ag{sub 8}Al{sub 8} (at.%) alloy has been studied. The crystalline phases were characterized by X-ray diffraction, optical microscopy and scanning electron microscopy with energy dispersive X-ray spectroscopy, and identified as AlCu{sub 2}Zr, Cu{sub 10}Zr{sub 7} and CuZr{sub 2}. The solidification sequence was established as following: the Cu{sub 10}Zr{sub 7} phase forms first in the periphery of the rod, then following with AlCu{sub 2}Zr phase in the rod center and finally CuZr{sub 2} crystals in Cu-depleted areas. The effect of crystals on the mechanical properties of the Cu{sub 40}Zr{sub 44}Ag{sub 8}Al{sub 8} alloy was also estimated through the microhardness. According to the value of microhardness, inhomogeneous structure of the amorphous matrix is more easily formed for the alloy in the low cooling rate (i.e., 9 mm) as compared with the alloy with fully amorphous state in the large cooling rate (i.e., 3 mm). This inhomogeneous structure was attributed to the composition change of amorphous matrix arising from the forming of crystalline phases due to the low cooling rate. - Highlights: Black-Right-Pointing-Pointer The crystalline phases in the Cu{sub 40}Zr{sub 44}Ag{sub 8}Al{sub 8} alloy were identified. Black-Right-Pointing-Pointer The solidification sequence of Cu{sub 40}Zr{sub 44}Ag{sub 8}Al{sub 8} alloy was verified. Black-Right-Pointing-Pointer The softening and hardening of alloy could be observed due to the crystallization.

  1. Effect of Cu addition on the martensitic transformation of powder metallurgy processed Ti–Ni alloys

    SciTech Connect

    Kim, Yeon-wook; Choi, Eunsoo

    2014-10-15

    Highlights: • M{sub s} of Ti{sub 50}Ni{sub 50} powders is 22 °C, while M{sub s} of SPS-sintered porous bulk increases up to 50 °C. • M{sub s} of Ti{sub 50}Ni{sub 40}Cu{sub 20} porous bulk is only 2 °C higher than that of the powders. • Recovered stain of porous TiNi and TiNiCu alloy is more than 1.5%. - Abstract: Ti{sub 50}Ni{sub 50} and Ti{sub 50}Ni{sub 30}Cu{sub 20} powders were prepared by gas atomization and their transformation behaviors were examined by means of differential scanning calorimetry and X-ray diffraction. One-step B2–B19’ transformation occurred in Ti{sub 50}Ni{sub 50} powders, while Ti{sub 50}Ni{sub 30}Cu{sub 20} powders showed B2–B19 transformation behavior. Porous bulks with 24% porosity were fabricated by spark plasma sintering. The martensitic transformation start temperature (50 °C) of Ti{sub 50}Ni{sub 50} porous bulk is much higher than that (22 °C) of the as-solidified powders. However, the martensitic transformation start temperature (35 °C) of Ti{sub 50}Ni{sub 30}Cu{sub 20} porous bulk is almost the same as that (33 °C) of the powders. When the specimens were compressed to the strain of 8% and then unloaded, the residual strains of Ti{sub 50}Ni{sub 50} and Ti{sub 50}Ni{sub 30}Cu{sub 20} alloy bulks were 3.95 and 3.7%, respectively. However, these residual strains were recovered up to 1.7% after heating by the shape memory phenomenon.

  2. Diselenophosphate-Induced Conversion of an Achiral [Cu 20 H 11 {S 2 P(O i Pr) 2 } 9 ] into a Chiral [Cu 20 H 11 {Se 2 P(O i Pr) 2 } 9 ] Polyhydrido Nanocluster

    DOE PAGES [OSTI]

    Dhayal, Rajendra S.; Liao, Jian-Hong; Wang, Xiaoping; Liu, Yu-Chiao; Chiang, Ming-His; Kahlal, Samia; Saillard, Jean-Yves; Liu, C. W.

    2015-11-09

    A polyhydrido copper nanocluster, [Cu20H11{Se2P(OiPr)2}9] (2H), which exhibits an intrinsically chiral inorganic core of C-3 symmetry, was synthesized from achiral [Cu20H11{S2P(OiPr)2}9] (1(H)) of C-3h symmetry by a ligand-exchange method. Likewise, the structure has a distorted cuboctahedral Cu-13 core, two triangular faces of which are capped along the C-3 axis, one by a Cu-6 cupola and the other by a single Cu atom. The Cu-20 framework is further stabilized by 9 diselenophosphate and 11 hydride ligands. The number of hydride, phosphorus, and selenium resonances and their splitting patterns in multinuclear NMR spectra of 2(H) indicate that the chiral Cu20H11 core retainsmore » its C-3 symmetry in solution. Moreover, the 11 hydride ligands were located by neutron diffraction experiments and shown to be capping (3)-H and interstitial (5)-H ligands (in square-pyramidal and trigonal-bipyramidal cavities), as supported by DFT calculations on [Cu20H11(Se2PH2)9] (2H') as a simplified model.« less

  3. Mechanism of Methanol Synthesis on Cu through CO2 and CO Hydrogenation

    SciTech Connect

    Grabow, Lars C.; Mavrikakis, Manos

    2011-03-04

    We present a comprehensive mean-field microkinetic model for the methanol synthesis and water-gas-shift (WGS) reactions that includes novel reaction intermediates, such as formic acid (HCOOH) and hydroxymethoxy (CH?O?) and allows for the formation of formic acid (HCOOH), formaldehyde (CH?O), and methyl formate (HCOOCH?) as byproducts. All input model parameters were initially derived from periodic, self-consistent, GGA-PW91 density functional theory calculations on the Cu(111) surface and subsequently fitted to published experimentalmethanol synthesis rate data, which were collected under realistic conditions on a commercial Cu/ZnO/Al?O? catalyst. We find that the WGS reaction follows the carboxyl (COOH)-mediated path and that both CO and CO? hydrogenation pathways are active for methanol synthesis. Under typical industrial methanol synthesis conditions, CO? hydrogenation is responsible for ?2/3 of the methanol produced. The intermediates of the CO? pathway for methanol synthesis include HCOO*, HCOOH*, CH?O?*, CH?O*, and CH?O*. The formation of formate (HCOO*) from CO?* and H* on Cu(111) does not involve an intermediate carbonate (CO?*) species, and hydrogenation of HCOO* leads to HCOOH* instead of dioxymethylene (H?CO?*). The effect of CO is not only promotional; CO* is also hydrogenated in significant amounts to HCO*, CH?O *, CH?O*, and CH?OH*. We considered two possibilities for CO promotion: (a) removal of OH* via COOH* to form CO? and hydrogen (WGS), and (b) CO-assisted hydrogenation of various surface intermediates, with HCO* being the H-donor. Only the former mechanism contributes to methanol formation, but its effect is small compared with that of direct CO hydrogenation to methanol. Overall, methanol synthesis rates are limited by methoxy (CH?O*) formation at low CO?/(CO+CO?) ratios and by CH?O* hydrogenation in CO?-rich feeds. CH?O* hydrogenation is the common slow step for both the CO and the CO? methanol synthesis routes; the relative contribution of

  4. Semiconductor bridge, SCB, ignition studies of Al/CuO thermite

    SciTech Connect

    Bickes, R.W. Jr.; Wackerbarth, D.E.; Mohler, J.H.

    1997-04-01

    The authors briefly summarize semiconductor bridge operation and review their ignition studies of Al/CuO thermite as a function of the capacitor discharge unit (CDU) firing set capacitance, charge holder material and morphology of the CuO. Ignition thresholds were obtained using a brass charge holder and a non-conducting fiber-glass-epoxy composite material, G10. At - 18 C and a charge voltage of 50V, the capacitance thresholds were 30.1 {mu}F and 2.0 {mu}F respectively. They also present new data on electrostatic discharge (ESD) and radio frequency (RF) vulnerability tests.

  5. Electronic band structure imaging of three layer twisted graphene on single crystal Cu(111)

    SciTech Connect

    Marquez Velasco, J.; Department of Physics, National Technical University of Athens, Athens ; Kelaidis, N.; Xenogiannopoulou, E.; Tsoutsou, D.; Tsipas, P.; Speliotis, Th.; Pilatos, G.; Likodimos, V.; Falaras, P.; Dimoulas, A.; Raptis, Y. S.

    2013-11-18

    Few layer graphene (FLG) is grown on single crystal Cu(111) by Chemical Vapor Deposition, and the electronic valence band structure is imaged by Angle-Resolved Photo-Emission Spectroscopy. It is found that graphene essentially grows polycrystalline. Three nearly ideal Dirac cones are observed along the Cu ?{sup }K{sup } direction in k-space, attributed to the presence of ?4 twisted three layer graphene with negligible interlayer coupling. The number of layers and the stacking order are compatible with Raman data analysis demonstrating the complementarity of the two techniques for a more accurate characterization of FLG.

  6. Molecular dynamics simulations of organic SIMS with Cu{sub n} (n=1-3) clusters

    SciTech Connect

    Townes, J. A.; White, A. K.; Krantzman, K. D.; Garrison, B. J.

    1999-06-10

    Molecular dynamics simulations have been performed to study the effect of cluster size on the emission yield and damage cross section in organic SIMS. A model system composed of a monolayer of biphenyl molecules on a Cu(001) substrate was bombarded with Cu{sub n} (n=1-3) projectiles at kinetic energies of 0.100 keV per atom. The yield increases with cluster size, but a nonlinear enhancement in yield is not observed. The yield-to-damage ratio, on the other hand, increases with the use of clusters, indicating that clusters have the potential to improve the sensitivity of SIMS.

  7. Synthesis of highly phase pure (Bi, Pb)-Sr-Ca-Cu-O superconductor

    DOEpatents

    Dorris, Stephen E.; Poeppel, Roger B.; Prorok, Barton C.; Lanagan, Michael T.; Maroni, Victor A.

    1994-01-01

    An article and method of manufacture of (Bi,Pb)-Sr-Ca-Cu-O superconductor. The superconductor is manufactured by preparing a first powdered mixture of bismuth oxide, lead oxide, strontium carbonate, calcium carbonate and copper oxide. A second powdered mixture is then prepared of strontium carbonate, calcium carbonate and copper oxide. The mixtures are calcined separately with the two mixtures then combined. The resulting combined mixture is then subjected to a powder in tube deformation and thermal processing to produce a substantially phase pure (Bi,Pb)-Sr-Ca-Cu-O superconductor.

  8. Synthesis of highly phase pure (Bi, Pb)-Sr-Ca-Cu-O superconductor

    DOEpatents

    Dorris, S.E.; Poeppel, R.B.; Prorok, B.C.; Lanagan, M.T.; Maroni, V.A.

    1994-10-11

    An article and method of manufacture of (Bi,Pb)-Sr-Ca-Cu-O superconductor are disclosed. The superconductor is manufactured by preparing a first powdered mixture of bismuth oxide, lead oxide, strontium carbonate, calcium carbonate and copper oxide. A second powdered mixture is then prepared of strontium carbonate, calcium carbonate and copper oxide. The mixtures are calcined separately with the two mixtures then combined. The resulting combined mixture is then subjected to a powder in tube deformation and thermal processing to produce a substantially phase pure (Bi,Pb)-Sr-Ca-Cu-O superconductor. 5 figs.

  9. Method of producing superconducting fibers of YBA2CU30X

    DOEpatents

    Schwartzkopf, Louis A.; Ostenson, Jerome E.; Finnemore, Douglas K.

    1990-11-13

    Fibers of YBa.sub.2 Cu.sub.3 O.sub.x have been produce by pendant drop melt extraction. This technique involves the end of a rod of YBa.sub.2 Cu.sub.3 O.sub.x melted with a hydrogen-oxygen torch, followed by lowering onto the edge of a spinning wheel. The fibers are up to 10 cm in length with the usual lateral dimensions, ranging from 20 .mu.m to 125 .mu.m. The fibers require a heat treatment to make them superconducting.

  10. High-power laser interaction with low-density C–Cu foams

    SciTech Connect

    Pérez, F.; Colvin, J. D.; May, M. J.; Charnvanichborikarn, S.; Kucheyev, S. O.; Fournier, K. B.; Felter, T. E.

    2015-11-15

    We study the propagation of high-power laser beams in micro-structured carbon foams by monitoring the x-ray output from deliberately introduced Cu content. In particular, we characterize this phenomenon measuring absolute time-resolved x-ray yields, time-resolved x-ray imaging, and x-ray spectroscopy. New experimental results for C–Cu foams show a faster heat front velocity than simulation that assumed homogeneous plasma. We suggest the foam micro-structure may explain this trend.

  11. A study of transport properties in Cu and P doped ZnSb

    SciTech Connect

    Valset, K.; Song, X.; Finstad, T. G.

    2015-01-28

    ZnSb samples have been doped with copper and phosphorus and sintered at 798 K. Electronic transport properties are interpreted as being influenced by an impurity band close to the valence band. At low Cu dopant concentrations, this impurity band degrades the thermoelectric properties as the Seebeck coefficient and effective mass are reduced. At carrier concentrations above 1 × 10{sup 19 }cm{sup −3}, the Seebeck coefficient in Cu doped samples can be described by a single parabolic band.

  12. Concentration-dependent surface-state shifts: Au on Cu(001)

    SciTech Connect

    Hansen, J.C. ); Wagner, M.K. . Dept. of Chemistry); Tobin, J.G. )

    1991-04-01

    High-resolution angle-resolved photoemission has been used to investigate the behavior of the Cu(001) {bar M}{sub 2} surface state as a function of Au coverage and substrate temperature. Binding-energy shifts of this state are dependent on the concentration of Au atoms substituted into the top surface layer of the Cu(001) substrate. The results demonstrate the use of surface-localized Tamm states as a specific probe of the chemical environment in the surface plane. 19 refs., 3 figs.

  13. 3-D Point Defect Density Distributions in Thin Film Cu(In,Ga)Se2 Measured

    Office of Scientific and Technical Information (OSTI)

    by Atom Probe Tomography (Journal Article) | SciTech Connect 3-D Point Defect Density Distributions in Thin Film Cu(In,Ga)Se2 Measured by Atom Probe Tomography Citation Details In-Document Search Title: 3-D Point Defect Density Distributions in Thin Film Cu(In,Ga)Se2 Measured by Atom Probe Tomography Authors: Stokes, Adam ; Al-Jassim, Mowafak ; Dierks, David R. ; Egaas, Brian ; Gorman, Brian Publication Date: 2016-01-01 OSTI Identifier: 1226163 Report Number(s): NREL/JA-5K00-62472 Journal

  14. In-situ TEM study of Cu-Ag nanoparticle thermal interaction. (Conference) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Conference: In-situ TEM study of Cu-Ag nanoparticle thermal interaction. Citation Details In-Document Search Title: In-situ TEM study of Cu-Ag nanoparticle thermal interaction. Abstract not provided. Authors: Lu, Ping Publication Date: 2013-10-01 OSTI Identifier: 1113336 Report Number(s): SAND2013-8356C 476492 DOE Contract Number: AC04-94AL85000 Resource Type: Conference Resource Relation: Conference: Proposed for presentation at the Rio Grande symposium held October 7, 2013

  15. Neutron diffraction study of the magnetic ordering of the Cu sup ++ spins in Nd sub 1. 5 Ba sub 1. 5 Cu sub 3 O sub 6+x

    SciTech Connect

    Moudden, A.H.; Hennion, B. - Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette ); Schweiss, P. - Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette Kernforschungszentrum Karlsruhe GmbH . Inst. fuer Nukleare Festkoerperphysik); Gehring, P.M.; Shirane, G. (Brookhaven National Lab., Upton, NY (

    1991-01-01

    Elastic neutron scattering experiments performed on single crystals of Nd{sub 1.5}Ba{sub 1.5}Cu{sub 3}O{sub 6+y} reveal successive antiferromagnetic (AF) ordering of the Cu{sup ++} spins. The as grown single crystals show an AF structure characterized by a Neel temperature T{sub N1} {approximately} 390K and a magnetic wave vector (1/2 1/2 0) referring to the tetragonal structure of NdBa{sub 2}Cu{sub 3}O{sub 6}. As the temperature is lowered below T{sub N2} {approximately} 150K, a spin reorientation develops and a second AF ordering with (1/2 1/2 1/2) wave vector is stabilized. When the samples are oxygenated the tetragonal symmetry and the Neel temperature T{sub N1} remain unchanged, whereas the spin reorientation at T{sub N2} is suppressed. The results indicate that the Nd/Ba substitution increases the stability of the tetragonal structure upon the oxygen content. This may induce new possibilities of local oxygen ordering that favour the presence of holes in the deficient layer.

  16. Composition dependence of the in-plane Cu-O bond-stretching LO phonon mode in YBa2Cu3O6+x

    SciTech Connect

    Stercil, F.; Egami, T.; Mook Jr, Herbert A; Yethiraj, Mohana; Chung, J.-H.; Arai, M.; Frost, C.; Dogan, F.

    2008-01-01

    An inelastic pulsed neutron scattering study was performed on the dependence of the dispersion and spectral intensity of the in-plane Cu-O bond-stretching LO phonon mode on doped charge density. The measurements were made in the time-of-flight mode with the multiangle position sensitive spectrometer of the ISIS facility on single crystals of YBa{sub 2}Cu{sub 3}O{sub 6+x} (x=0.15, 0.35, 0.6, 0.7, and 0.95). The focus of the study is the in-plane Cu-O bond-stretching LO phonon mode, which is known for strong electron-phonon coupling and unusual dependence on composition and temperature. It is shown that the dispersions for the samples with x=0.35, 0.6, and 0.7 are similar to the superposition of those for x=0.15 and 0.95 samples, and cannot be explained in terms of the structural anisotropy. It is suggested that the results are consistent with the model of nanoscale electronic phase separation, with the fraction of the phases being dependent on the doped charge density.

  17. Magnetic field dependence of high- Tc interface superconductivity in La1.55Sr0.45CuO4/La2CuO4 heterostructures

    DOE PAGES [OSTI]

    Gasparov, V. A.; Drigo, L.; Audouard, A.; He, Xi; Božović, I.

    2016-07-11

    Heterostructures made of a layer of a cuprate insulator La2CuO4 on the top of a layer of a nonsuperconducting cuprate metal La1.55Sr0.45CuO4 show high-Tc interface superconductivity confined within a single CuO2 plane. Given this extreme quasi-two-dimensional quantum confinement, it is of interest to find out how interface superconductivity behaves when exposed to an external magnetic field. With this motivation, we have performed contactless tunnel-diode-oscillator-based measurements in pulsed magnetic fields up to 56 T as well as measurements of the complex mutual inductance between a spiral coil and the film in static fields up to 3 T. Remarkably, we observe thatmore » interface superconductivity survives up to very high perpendicular fields, in excess of 40 T. Additionally, the critical magnetic field Hm(T) reveals an upward divergence with decreasing temperature, in line with vortex melting as in bulk superconducting cuprates.« less

  18. Low cost, surfactant-less, one pot synthesis of Cu{sub 2}O nano-octahedra at room temperature

    SciTech Connect

    Ahmed, Asar; Gajbhiye, Namdeo S.; Joshi, Amish G.

    2011-08-15

    Cu{sub 2}O octahedra were successfully synthesized via a novel wet-chemical method using D-glucose and hydrazine as reducing agent at room temperature without the presence of any other surfactant. Presence of D-glucose was important for the stabilization of the evolved copper octahedra and also for facilitating the reduction of the Cu(II) ions. The existence of glucose moieties on the surface as capping agent was confirmed by the FT-IR spectra while there was presence of excess oxygen atoms on the surface leading to the formation of a thin CuO layer at the octahedra surface, as confirmed by the XPS study, probably promoted by the capping glucose. Effect of NaOH concentration on the reaction and the formation of octahedra was also studied. The formation mechanism of obtained Cu{sub 2}O octahedra has been discussed. These octahedra were then studied for their photocatalytic properties in degradation of organic dyes, rhodamine B and methyl orange. - Graphical abstract: Cu{sub 2}O octahedra were found to have thin layer of CuO, due to oxidation of surface Cu{sup +} atoms by the surfactant O atoms. Highlights: > Simple and inexpensive one pot synthesis of various Cu{sub 2}O nanostructures. > Surface properties studied by XPS. > Used as photocatalysis for degradation of rhodamine B.

  19. Hydrogenation of CO2 to methanol on CeOx/Cu(111) and ZnO/Cu(111) catalysts: Role of the metal-oxide interface and importance of Ce3+ sites

    DOE PAGES [OSTI]

    Sanjaya D. Senanayake; Ramirez, Pedro J.; Waluyo, Iradwikanari; Kundu, Shankhamala; Mudiyanselage, Kumudu; Liu, Zongyuan; Liu, Zhi; Axnanda, Stephanus; Stacchiola, Dario J.; Evans, Jaime; et al

    2016-01-06

    The role of the interface between a metal and oxide (CeOx–Cu and ZnO–Cu) is critical to the production of methanol through the hydrogenation of CO2 (CO2 + 3H2 → CH3OH + H2O). The deposition of nanoparticles of CeOx or ZnO on Cu(111), θoxi < 0.3 monolayer, produces highly active catalysts for methanol synthesis. The catalytic activity of these systems increases in the sequence: Cu(111) < ZnO/Cu(111) < CeOx/Cu(111). The apparent activation energy for the CO2 → CH3OH conversion decreases from 25 kcal/mol on Cu(111) to 16 kcal/mol on ZnO/Cu(111) and 13 kcal/mol on CeOx/Cu(111). The surface chemistry of the highlymore » active CeOx–Cu(111) interface was investigated using ambient pressure X-ray photoemission spectroscopy (AP-XPS) and infrared reflection absorption spectroscopy (AP-IRRAS). Both techniques point to the formation of formates (HCOO–) and carboxylates (CO2δ–) during the reaction. Our results show an active state of the catalyst rich in Ce3+ sites which stabilize a CO2δ– species that is an essential intermediate for the production of methanol. Furthermore, the inverse oxide/metal configuration favors strong metal–oxide interactions and makes possible reaction channels not seen in conventional metal/oxide catalysts.« less

  20. ZnO/Cu(InGa)Se.sub.2 solar cells prepared by vapor phase Zn doping

    DOEpatents

    Ramanathan, Kannan; Hasoon, Falah S.; Asher, Sarah E.; Dolan, James; Keane, James C.

    2007-02-20

    A process for making a thin film ZnO/Cu(InGa)Se.sub.2 solar cell without depositing a buffer layer and by Zn doping from a vapor phase, comprising: depositing Cu(InGa)Se.sub.2 layer on a metal back contact deposited on a glass substrate; heating the Cu(InGa)Se.sub.2 layer on the metal back contact on the glass substrate to a temperature range between about 100.degree. C. to about 250.degree. C.; subjecting the heated layer of Cu(InGa)Se.sub.2 to an evaporant species from a Zn compound; and sputter depositing ZnO on the Zn compound evaporant species treated layer of Cu(InGa)Se.sub.2.

  1. Effect of the Keggin anions on assembly of Cu{sup I}-bis(tetrazole) thioether complexes containing multinuclear Cu{sup I}-cluster

    SciTech Connect

    Wang Xiuli; Gao Qiang; Tian Aixiang; Hu Hailiang; Liu Guocheng

    2012-03-15

    In order to investigate the effect of polyoxometalate (POM) on the assembly of transition metal-bis(tetrazole) thioether complexes, three new complexes based on different Keggin anions and multinuclear Cu{sup I}-cluster [Cu{sup I}{sub 12}(bmtr){sub 9}(HSiMo{sub 12}O{sub 40}){sub 4}] (1), [Cu{sup I}{sub 3}(bmtr){sub 3}(PM{sub 12}O{sub 40})] (M=W for 2; Mo for 3) (bmtr=1,3-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)propane), have been hydrothermally synthesized and characterized by routine physical methods and single crystal X-ray diffraction. In compound 1, two kinds of nanometer-scale tetranuclear subunits linked by [SiMo{sub 12}O{sub 40}]{sup 4-} polyanions assemble a (3, 4)-connected three-dimensional (3D) self-penetrating framework. Compounds 2 and 3 are isostructural, exhibiting a 1D chain with [PW{sub 12}O{sub 40}]{sup 3-}/[PMo{sub 12}O{sub 40}]{sup 3-} polyanions and trinuclear clusters arranging alternately. The distinct structural differences between these POM-based Cu{sup I}-bmtr complexes of 1 and 2/3 maybe rest on the contrast of Keggin-type polyoxometalate with different central heteroatoms, which have been discussed in detail. In addition, the electrochemical properties of the title complexes have been investigated. - Graphical abstract: Three new complexes based on different Keggin anions and multinuclear Cu{sup I}-cluster have been synthesized under hydrothermal conditions. The Keggin polyanions with different central heteroatoms play a key role. Highlights: Black-Right-Pointing-Pointer The flexible bis(tetrazole)-based thioether ligand with some advantages have been used. Black-Right-Pointing-Pointer The effect of Keggin anions with different central heteroatoms has been discussed in detail. Black-Right-Pointing-Pointer The electrochemical behaviors and electrocatalysis property have been investigated.

  2. Photocatalytic performances and activities of Ag-doped CuFe{sub 2}O{sub 4} nanoparticles

    SciTech Connect

    Zhu, Zhengru; Li, Xinyong; Zhao, Qidong; Li, Yonghua; Sun, Caizhi; Cao, Yongqiang

    2013-08-01

    Graphical abstract: - Highlights: CuFe{sub 2}O{sub 4} nanocrystals were synthesized by a co-precipitation method. Ag/CuFe{sub 2}O{sub 4} catalyst was prepared by the wetness impregnation strategy. The structural properties of Ag/CuFe{sub 2}O{sub 4} were investigated by XRD, TEM, DRS, and XPS techniques. Ag/CuFe{sub 2}O{sub 4} has higher photocatalytic activity. - Abstract: In this work, CuFe{sub 2}O{sub 4} nanoparticles were synthesized by a chemical co-precipitation route. The Ag/CuFe{sub 2}O{sub 4} catalyst was prepared based on the CuFe{sub 2}O{sub 4} nanoparticles by the incipient wetness impregnation strategy, which showed excellent photoelectric property and catalytic activity. The structural properties of these samples were systematically investigated by X-ray powder diffraction (XRD), transmission electronic microscopy (TEM), UVvis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) techniques. The photo-induced charge separation in the samples was demonstrated by surface photovoltage (SPV) measurement. The photocatalytic degradation of 4-CP by the Ag/CuFe{sub 2}O{sub 4} and CuFe{sub 2}O{sub 4} samples were comparatively studied under xenon lamp irradiation. The results indicate that the Ag/CuFe{sub 2}O{sub 4} sample exhibited the higher efficiency for the degradation of 4-CP.

  3. Photoinduced Br Desorption from CsBr Thin Films Grown on Cu(100)

    SciTech Connect

    Halliday, Matthew T.; Joly, Alan G.; Hess, Wayne P.; Shluger, AL

    2015-10-22

    Thin films of CsBr deposited onto metals such as copper are potential photocathode materials for light sources and other applications. We investigate desorption dynamics of Br atoms from CsBr films grown on insulator (KBr, LiF) and metal (Cu) substrates induced by sub-bandgap 6.4 eV laser pulses. The experimental results demonstrate that the peak kinetic energy of Br atoms desorbed from CsBr/Cu films is much lower than that for the hyperthermal desorption from CsBr/LiF films. Kelvin probe measurements indicate negative charge at the surface following Br desorption from CsBr/Cu films. Our ab initio calculations of excitons at CsBr surfaces demonstrate that this behavior can be explained by an exciton model of desorption including electron trapping at the CsBr surface. Trapped negative charges reduce the energy of surface excitons available for Br desorption. We examine the electron-trapping characteristics of low-coordinated sites at the surface, in particular, divacancies and kink sites. We also provide a model of cation desorption caused by Franck-Hertz excitation of F centers at the surface in the course of irradiation of CsBr/Cu films. These results provide new insights into the mechanisms of photoinduced structural evolution of alkali halide films on metal substrates and activation of metal photocathodes coated with CsBr.

  4. Phase transitions in delafossite CuLaO{sub 2} at high pressures

    SciTech Connect

    Salke, Nilesh P.; Rao, Rekha Gupta, M. K.; Mittal, R.; Garg, Alka B.; Achary, S. N.; Tyagi, A. K.

    2014-04-07

    Structural stability of a transparent conducting oxide CuLaO{sub 2} at high pressures is investigated using in-situ Raman spectroscopy, electrical resistance, and x-ray diffraction techniques. The present Raman investigations indicate a sequence of structural phase transitions at 1.8?GPa and 7?GPa. The compound remains in the first high pressure phase when pressure is released. Electrical resistance measurements carried out at high pressures confirm the second phase transition. These observations are further supported by powder x-ray diffraction at high pressures which also showed that a-axis is more compressible than c-axis in this compound. Fitting the pressure dependence of unit cell volume to 3{sup rd} order Birch-Murnaghan equation of state, zero pressure bulk modulus of CuLaO{sub 2} is determined to be 154(25) GPa. The vibrational properties in the ambient delafossite phase of CuLaO{sub 2} are investigated using ab-initio calculations of phonon frequencies to complement the Raman spectroscopic measurements. Temperature dependence of the Raman modes of CuLaO{sub 2} is investigated to estimate the anharmonicity of Raman modes.

  5. Preparation of Bi-Sr-Ca-Cu-O superconductors from oxide-glass precursors

    DOEpatents

    Hinks, David G.; Capone, II, Donald W.

    1992-01-01

    A superconductor and precursor therefor from oxide mixtures of Ca, Sr, Bi and Cu. Glass precursors quenched to elevated temperatures result in glass free of crystalline precipitates having enhanced mechanical properties. Superconductors are formed from the glass precursors by heating in the presence of oxygen to a temperature below the melting point of the glass.

  6. Energetics of the formation of Cu-Ag core–shell nanoparticles

    SciTech Connect

    Chandross, Michael

    2014-10-06

    Our work presents molecular dynamics and Monte Carlo simulations aimed at developing an understanding of the formation of core–shell Cu-Ag nanoparticles. The effects of surface and interfacial energies were considered and used to form a phenomenological model that calculates the energy gained upon the formation of a core–shell structure from two previously distinct, non-interacting nanoparticles. In most cases, the core–shell structure was found to be energetically favored. Specifically, the difference in energy as a function of the radii of the individual Cu and Ag particles was examined, with the assumption that a core–shell structure forms. In general, it was found that the energetic gain from forming such a structure increased with increasing size of the initial Ag particle. This result was interpreted as a result of the reduction in surface energy. Moreover, for two separate particles, both Cu and Ag contribute to the surface energy; however, for a core–shell structure, the only contribution to the surface energy is from the Ag shell and the Cu contribution is changed to a Cu–Ag interfacial energy, which is always smaller.

  7. Synthesis of YBa2CU3O7 using sub-atmospheric processing

    DOEpatents

    Wiesmann, Harold; Solovyov, Vyacheslav

    2004-09-21

    The present invention is a method of forming thick films of crystalline YBa.sub.2 Cu.sub.3 O.sub.7 that includes forming a precursor film comprising barium fluoride (BaF.sub.2), yttrium (Y) and copper (Cu). The precursor film is heat-treated at a temperature above 500.degree. C. in the presence of oxygen, nitrogen and water vapor at sub-atmospheric pressure to form a crystalline structure. The crystalline structure is then annealed at about 500.degree. C. in the presence of oxygen to form the crystalline YBa.sub.2 Cu.sub.3 O.sub.7 film. The YBa.sub.2 Cu.sub.3 O.sub.7 film formed by this method has a resistivity of from about 100 to about 600 .mu.Ohm-cm at room temperature and a critical current density measured at 77 K in a magnetic field of 1 Tesla of about 1.0.times.10.sup.5 Ampere per square centimeter (0.1 MA/cm.sup.2) or greater.

  8. X-ray imaging and controlled solidification of Al-Cu alloys toward microstructures by design

    DOE PAGES [OSTI]

    Clarke, Amy J.; Tourret, Damien; Imhoff, Seth D.; Gibbs, Paul J.; Fezzaa, Kamel; Cooley, Jason C.; Lee, Wah -Keat; Deriy, Alex; Patterson, Brian M.; Papin, Pallas A.; et al

    2015-01-30

    X-ray imaging, which permits the microscopic visualization of metal alloy solidification dynamics, can be coupled with controlled solidification to create microstructures by design. This x-ray image shows a process-derived composite microstructure being made from a eutectic Al-17.1 at.%Cu alloy by successive solidification and remelting steps.

  9. Structural phase transition and phonon instability in Cu12Sb4S13

    DOE PAGES [OSTI]

    May, Andrew F.; Delaire, Olivier A.; Niedziela, Jennifer L.; Lara-Curzio, Edgar; Susner, Michael A.; Abernathy, Douglas L.; Kirkham, Melanie J.; McGuire, Michael A.

    2016-02-08

    In this study, a structural phase transition has been discovered in the synthetic tetrahedrite Cu12Sb4S13 at approximately 88 K. Upon cooling, the material transforms from its known cubic symmetry to a tetragonal unit cell that is characterized by an in-plane ordering that leads to a doubling of the unit cell volume. Specific heat capacity measurements demonstrate a hysteresis of more than two degrees in the associated anomaly. A similar hysteresis was observed in powder x-ray diffraction measurements, which also indicate a coexistence of the two phases, and together these results suggest a first-order transition. This structural transition coincides with amore » recently-reported metal-insulator transition, and the structural instability is related to the very low thermal conductivity κ in these materials. Inelastic neutron scattering was used to measure the phonon density of states in Cu12Sb4S13 and Cu10Zn2Sb4S13, both of which possess a localized, low-energy phonon mode associated with strongly anharmonic copper displacements that suppress κ. In Cu12Sb4S13, signatures of the phase transition are observed in the temperature dependence of the localized mode, which disappears at the structural transition. In contrast, in the cubic Zn-doped material, the mode is at slightly higher-energy but observable for all temperatures, though it softens upon cooling.« less

  10. Local structure order in Pd78Cu6Si16 liquid

    DOE PAGES [OSTI]

    Yue, G. Q.; Zhang, Y.; Sun, Y.; Shen, B.; Dong, F.; Wang, Z. Y.; Zhang, R. J.; Zheng, Y. X.; Kramer, M. J.; Wang, S. Y.; et al

    2015-02-05

    The short-range order (SRO) in Pd78Cu6Si16 liquid was studied by high energy x-ray diffraction and ab initio molecular dynamics (MD) simulations. The calculated pair correlation functions at different temperatures agree well with the experimental results. The partial pair correlation functions from ab intio MD simulations indicate that Si atoms prefer to be uniformly distributed while Cu atoms tend to aggregate. By performing structure analysis using Honeycutt-Andersen index, Voronoi tessellation, and atomic cluster alignment method, we show that the icosahedron and face-centered cubic SRO increase upon cooling. The dominant SRO is the Pd-centered Pd9Si2 motif, namely the structure of which motifmore » is similar to the structure of Pd-centered clusters in the Pd9Si2 crystal. The study further confirms the existence of trigonal prism capped with three half-octahedra that is reported as a structural unit in Pd-based amorphous alloys. The majority of Cu-centered clusters are icosahedra, suggesting that the presence of Cu is benefit to promote the glass forming ability.« less

  11. Potential energy curves for the ground and low-lying excited states of CuAg

    SciTech Connect

    Alizadeh, Davood; Shayesteh, Alireza E-mail: ashayesteh@ut.ac.ir; Jamshidi, Zahra E-mail: ashayesteh@ut.ac.ir

    2014-10-21

    The ground and low-lying excited states of heteronuclear diatomic CuAg are examined by multi-reference configuration interaction (MRCI) method. Relativistic effects were treated and probed in two steps. Scalar terms were considered using the spin-free DKH Hamiltonian as a priori and spin-orbit coupling was calculated perturbatively via the spin-orbit terms of the Breit-Pauli Hamiltonian based on MRCI wavefunctions. Potential energy curves of the spin-free states and their corresponding Ω components correlating with the separated atom limits {sup 2}S(Cu) + {sup 2}S(Ag) and {sup 2}D(Cu) + {sup 2}S(Ag) are obtained. The results are in fine agreement with the experimental measurements and tentative conclusions for the ion-pair B0{sup +} state are confirmed by our theoretical calculations. Illustrative results are presented to reveal the relative importance and magnitude of the scalar and spin-orbit effects on the spectroscopic properties of this molecule. Time dependent density functional theory calculations, using the LDA, BLYP, B3LYP, and SAOP functionals have been carried out for CuAg and the accuracy of TD-DFT has been compared with ab initio results.

  12. Structural phase transition and phonon instabilities in Cu12Sb4S13

    DOE PAGES [OSTI]

    May, Andrew F.; Delaire, Olivier A.; Niedziela, Jennifer L.; Lara-Curzio, Edgar; Susner, Michael A.; Abernathy, Douglas L.; Kirkham, Melanie J.; McGuire, Michael A.

    2016-02-08

    In this study, a structural phase transition has been discovered in the synthetic tetrahedrite Cu12Sb4S13 at approximately 88 K. Upon cooling, the material transforms from its known cubic symmetry to a tetragonal unit cell that is characterized by an in-plane ordering that leads to a doubling of the unit cell volume. Specific heat capacity measurements demonstrate a hysteresis of more than two degrees in the associated anomaly. A similar hysteresis was observed in powder x-ray diffraction measurements, which also indicate a coexistence of the two phases, and together these results suggest a first-order transition. This structural transition coincides with amore » recently-reported metal-insulator transition, and the structural instability is related to the very low thermal conductivity κ in these materials. Inelastic neutron scattering was used to measure the phonon density of states in Cu12Sb4S13 and Cu10Zn2Sb4S13, both of which possess a localized, low-energy phonon mode associated with strongly anharmonic copper displacements that suppress κ. In Cu12Sb4S13, signatures of the phase transition are observed in the temperature dependence of the localized mode, which disappears at the structural transition. In contrast, in the cubic Zn-doped material, the mode is at slightly higher-energy but observable for all temperatures, though it softens upon cooling.« less

  13. Magnon spectrum of the helimagnetic insulator Cu2OSeO3

    DOE PAGES [OSTI]

    Portnichenko, P. Y.; Romhányi, J.; Onykiienko, Y. A.; Henschel, A.; Schmidt, M.; Cameron, A. S.; Surmach, M. A.; Lim, J. A.; Park, J. T.; Schneidewind, A.; et al

    2016-02-25

    We report that complex low-temperature-ordered states in chiral magnets are typically governed by a competition between multiple magnetic interactions. The chiral-lattice multiferroic Cu2OSeO3 became the first insulating helimagnetic material in which a long-range order of topologically stable spin vortices known as skyrmions was established. Here we employ state-of-the-art inelastic neutron scattering to comprehend the full three-dimensional spin-excitation spectrum of Cu2OSeO3 over a broad range of energies. Distinct types of high- and low-energy dispersive magnon modes separated by an extensive energy gap are observed in excellent agreement with the previously suggested microscopic theory based on a model of entangled Cu4 tetrahedra.more » The comparison of our neutron spectroscopy data with model spin-dynamical calculations based on these theoretical proposals enables an accurate quantitative verification of the fundamental magnetic interactions in Cu2OSeO3 that are essential for understanding its abundant low-temperature magnetically ordered phases.« less

  14. Production of Cu-Al-Ni Shape Memory Alloys by Mechanical Alloy

    SciTech Connect

    Goegebakan, Musa; Soguksu, Ali Kemal; Uzun, Orhan; Dogan, Ali

    2007-04-23

    The mechanical alloying technique has been used to produce shape memory Cu83Al13Ni4 alloy. The structure and thermal properties were examined by using scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The morphology of the surface suggests the presence of martensite.

  15. Revisiting the inelastic electron tunneling spectroscopy of single hydrogen atom adsorbed on the Cu(100) surface

    SciTech Connect

    Jiang, Zhuoling; Wang, Hao; Sanvito, Stefano; Hou, Shimin

    2015-12-21

    Inelastic electron tunneling spectroscopy (IETS) of a single hydrogen atom on the Cu(100) surface in a scanning tunneling microscopy (STM) configuration has been investigated by employing the non-equilibrium Green’s function formalism combined with density functional theory. The electron-vibration interaction is treated at the level of lowest order expansion. Our calculations show that the single peak observed in the previous STM-IETS experiments is dominated by the perpendicular mode of the adsorbed H atom, while the parallel one only makes a negligible contribution even when the STM tip is laterally displaced from the top position of the H atom. This propensity of the IETS is deeply rooted in the symmetry of the vibrational modes and the characteristics of the conduction channel of the Cu-H-Cu tunneling junction, which is mainly composed of the 4s and 4p{sub z} atomic orbitals of the Cu apex atom and the 1s orbital of the adsorbed H atom. These findings are helpful for deepening our understanding of the propensity rules for IETS and promoting IETS as a more popular spectroscopic tool for molecular devices.

  16. Energetics of the formation of Cu-Ag core–shell nanoparticles

    DOE PAGES [OSTI]

    Chandross, Michael

    2014-10-06

    Our work presents molecular dynamics and Monte Carlo simulations aimed at developing an understanding of the formation of core–shell Cu-Ag nanoparticles. The effects of surface and interfacial energies were considered and used to form a phenomenological model that calculates the energy gained upon the formation of a core–shell structure from two previously distinct, non-interacting nanoparticles. In most cases, the core–shell structure was found to be energetically favored. Specifically, the difference in energy as a function of the radii of the individual Cu and Ag particles was examined, with the assumption that a core–shell structure forms. In general, it was foundmore » that the energetic gain from forming such a structure increased with increasing size of the initial Ag particle. This result was interpreted as a result of the reduction in surface energy. Moreover, for two separate particles, both Cu and Ag contribute to the surface energy; however, for a core–shell structure, the only contribution to the surface energy is from the Ag shell and the Cu contribution is changed to a Cu–Ag interfacial energy, which is always smaller.« less

  17. Low temperature synthesis of Ru–Cu alloy nanoparticles with the compositions in the miscibility gap

    SciTech Connect

    Martynova, S.A.; Filatov, E.Yu.; Korenev, S.V.; Kuratieva, N.V.; Sheludyakova, L.A.; Plusnin, P.E.; Shubin, Yu.V.; Slavinskaya, E.M.; Boronin, A.I.

    2014-04-01

    A complex salt [Ru(NH{sub 3}){sub 5}Cl][Cu(C{sub 2}O{sub 4}){sub 2}H{sub 2}O]—the precursor of nanoalloys combining ruthenium and copper was prepared. It crystallizes in the monoclinic space group P2{sub 1}/n. Thermal properties of the prepared salt were examined in different atmospheres (helium, hydrogen, oxygen). Thermal decomposition of the precursor in inert atmosphere was thoroughly examined and the intermediate products were characterized. Experimental conditions for preparation of copper-rich (up to 12 at% of copper) metastable solid solution Cu{sub x}Ru{sub 1−x} (based on Ru structure) were optimized, what is in sharp contrast to the bimetallic miscibility gap known for the bulk counterparts in a wide composition range. Catalytic properties of copper–ruthenium oxide composite were tested in catalytic oxidation of CO. - Highlights: • We synthesized new precursor of CuRu metastable nanoalloys. • Thermal properties of the prepared salt were examined in different atmospheres. • Thermodestruction mechanism of precursor are studied. • Cu{sub 0.12}Ru{sub 0.88} nanoalloy with the compositions in the miscibility gap is obtained. • Catalytic conversion of CO on copper–ruthenium oxide composite were examined.

  18. Evaluation of high strength, high conductivity CuNiBe alloys for fusion energy applications

    SciTech Connect

    Zinkle, Steven J

    2014-06-01

    The unirradiated tensile properties for several different heats and thermomechanical treatment conditions of precipitation strengthened Hycon 3HPTM CuNiBe (Cu-2%Ni-0.35%Be in wt.%) have been measured over the temperature range of 20-500 C for longitudinal and long transverse orientations. The room temperature electrical conductivity has also been measured for several heats, and the precipitate microstructure was characterized using transmission electron microscopy. The CuNiBe alloys exhibit very good combination of strength and conductivity at room temperature, with yield strengths of 630-725 MPa and electrical conductivities of 65-72% International Annealed Copper Standard (IACS). The strength remained relatively high at all test temperatures, with yield strengths of 420-520 MPa at 500 C. However, low levels of ductility (<5% uniform elongation) were observed at test temperatures above 200-250 C, due to flow localization near grain boundaries (exacerbated by having only 10-20 grains across the gage thickness of the miniaturized sheet tensile specimens). Scanning electron microscopy observation of the fracture surfaces found a transition from ductile transgranular to ductile intergranular fracture with increasing test temperature. Fission neutron irradiation to a dose of ~0.7 displacements per atom (dpa) at temperatures between 100 and 240 C produced a slight increase in strength and a significant decrease in ductility. The measured tensile elongation increased with increasing irradiation temperature, with a uniform elongation of ~3.3% observed at 240 C. The electrical conductivity decreased slightly following irradiation, due to the presence of defect clusters and Ni, Zn, Co transmutation products. Considering also previously published fracture toughness data, this indicates that CuNiBe alloys have irradiated tensile and electrical properties comparable or superior to CuCrZr and oxide dispersion strengthened copper at temperatures <250 C, and may be an attractive

  19. Effects of sintering temperature and duration on the structural and electrical properties of CuBiS{sub 2} bulks

    SciTech Connect

    Wubet, Walelign; Kuo, Dong-Hau Abdullah, Hairus

    2015-10-15

    CuBiS{sub 2} bulks were prepared by reactive sintering the mixture of Cu{sub 2}S and Bi{sub 2}S{sub 3} at 300, 350, 400, and 450 °C for 2 h and at the sintering temperature of 400 °C for 1, 1.5, 2, 2.5, and 3 h under a compensation disc of CuS for atmospheric control. Composition, structure, morphology, and electrical properties of the sintered bulks were analyzed. The compositions of Cu, Bi, and S did not change until the temperature reached at 450 °C.The highest electrical conductivity of 4.3 S cm{sup −1} and the highest Hall mobility of 11.1 cm{sup 2} V{sup −1} s{sup −1} were obtained for CuBiS{sub 2} sintered at 400 °C for 2 h. The deviation in the S/(Cu+Bi) ration caused the degradation of electrical properties, though the CuBiS{sub 2} remained as a single phase. Therefore, CuBiS{sub 2}, a less studied ternary copper based sulfide, is the p-type semiconductor for potential energy-related application and needs to have a good control in composition. - Graphical abstract: CuBiS{sub 2}, a less studied ternary copper based sulfide, is the p-type semiconductor and needs to have a good control in composition to achieve the optimal electrical properties. - Highlights: • CuBiS{sub 2}, a less studied copper-based sulfide, is a p-type semiconductor. • Electrical properties of CuBiS{sub 2} are important for its photovoltaic applications. • Deviation in composition leads a change in the electrical properties of CuBiS{sub 2}. • n of 2.4×10{sup 18} cm{sup −3}, μ of 11.1 cm{sup 2} V{sup −1} s{sup −1}, and σ of 4.3 S cm{sup −1} were obtained. • The process control in CuSbS{sub 2} is critical to achieve consistent performance.

  20. Cu(N-N){sub 2}Cl{sub 2} and Cu(N-N-N)Cl{sub 2} and HgCl{sub 2} building blocks in the synthesis of coordination compounds-X-ray studies and magnetic properties

    SciTech Connect

    Machura, B.; Switlicka, A.; Nawrot, I.; Mrozinski, J.; Kruszynski, R.; Kusz, J.

    2010-09-15

    A series of complexes containing Cu(N-N){sub 2}Cl{sub 2} (N-N=bis(pyrazol-1-yl)methane (bpzm), bis(3,5dimethylpyrazol-1-yl)methane (bdmpzm), 2,2-dipyridylamine (dpa), 5,6-diphenyl-3-(2-pyridyl)-1,2,4-trazine (dppt) and 2,2'-bipyridine (bipy)), Cu(N-N-N)Cl{sub 2} (N-N-N=2,2':6',2''-terpyridine (terpy)) and HgCl{sub 2} building blocks have been synthesized and structurally characterized. Increase in structural dimensionality is observed for [Cu(bpzm){sub 2}][HgCl{sub 4}], [Cu(dpa){sub 2}][HgCl{sub 3}]{sub 2} and [Cu(terpy)({mu}-Cl)HgCl{sub 3}] compounds. No coordination polymers have formed in the case of bis(3,5dimethylpyrazol-1-yl)methane, 5,6-diphenyl-3-(2-pyridyl)-1,2,4-trazine and 2,2'-bipyridine. The [Cu(bpzm){sub 2}][HgCl{sub 4}] and [Cu(terpy)({mu}-Cl)HgCl{sub 3}] complexes have been studied by magnetic measurements. - Graphical abstract: N-N: bis(3,5dimethylpyrazol-1-yl)methane (bdmpzm), 2,2-dipyridylamine (dpa), 5,6-diphenyl-3-(2-pyridyl)-1,2,4-trazine (dppt) and 2,2'-bipyridine (bipy), 6',2''-terpyridine (terpy).

  1. Synthesis, structure, and magnetic properties of a novel mixed-valence copper(I/II) phosphate, Cu{sub 2}PO{sub 4}

    SciTech Connect

    Etheredge, K.M.S.; Hwu, S.J.

    1995-09-27

    Via phase compatibility studies, a novel mixed-valence copper(I/II) phosphate, Cu{sub 2}PO{sub 4}, has been isolated from a direct reaction of Cu{sub 2}{sup I}O, Cu{sup II}O, and P{sub 2}O{sub 5} in fused silica. The single-crystal X-ray diffraction shows that the title compound crystallizes in a triclinic (P1) unit cell, with lattice dimensions a = 6.145(2) {angstrom}, b = 9.348(2) {angstrom}, c = 6.009(1) {angstrom}, {alpha} = 96.46(2){degrees}, {beta} = 100.16(2){degrees}, {gamma} = 73.97(2){degrees}, V = 325.8(1) {angstrom}{sup 3}; Z =4. The structure has been refined by the least-squares method to R = 0.019, R{sub w} = 0.030, and GOF = 1.43 for 128 variables. The four copper atoms in each asymmetric unit adopt three distorted coordination geometries that are consistent with the corresponding electronic states, e.g., square pyramidal Cu(1){sup II}O{sub 5}, octahedral Cu(2){sup II}O{sub 6}, and linear Cu(3,4){sup I}O{sub 2}. A low-dimensional framework exists consisting of arrays of nearly parallel CuO{sub 2} units which are separated by the nonmagnetic, closed-shell P{sup 5+} cation in PO{sub 4} tetrahedra. Closely spaced CuO{sub 2} chains and a relatively short Cu{sup I}-Cu{sup I} distance, e.g., 2.737 {angstrom} for Cu(3)-Cu(3), are attributed to the bond strength of the cross-linked PO{sub 4} tetrahedra. In the extended Cu(I/II)-O framework, short linkages of Cu{sup I}-O-Cu{sup II}-O-Cu{sup I} and Cu{sup II}-O-Cu{sup II}, composed of regular Cu-O bonds (1.86-1.99 {angstrom}), are interconnected through long Cu{sup II}-O bonds (2.36-2.74 {angstrom}). The magnetic measurements indicate that the Cu-O framework exhibits a spin 1/2 ground state and an antiferromagnetic ordering with a broad susceptibility maximum between 95 and 105 K. The results of stoichiometric synthesis, thermal analysis, and bond valence sum calculations of the title compound are also discussed.

  2. Probing the mechanism of sodium ion insertion into copper antimony Cu2Sb anodes

    DOE PAGES [OSTI]

    Baggetto, Loic; Carroll, Kyler J.; Hah, Hien -Yoong; Johnson, Charles E.; Mullins, David R.; Unocic, Raymond R.; Johnson, Jacqueline A.; Meng, Ying Shirley; Veith, Gabriel M.

    2014-03-25

    Cycling Cu2Sb films with fluoroethylene carbonate additive drastically improves the capacity retention of the electrode compared to cycling in pure PC with about 250 mAh g-1 retained capacity for about two hundred cycles. TEM photographs reveal that the pristine films are formed of nanoparticles of 5-20 nm diameters. XRD results highlight that during the first discharge the reaction leads to the formation of Na3Sb via an intermediate amorphous phase. During charge, Na3Sb crystallites convert into an amorphous phase, which eventually crystallizes into Cu2Sb at full charge, indicating a high degree of structural reversibility. The subsequent discharge is marked by amore » new plateau around 0.5 V at low Na/Sb content which does not correspond to the formation of a crystalline phase. XAS data show that the fully discharged electrode material has interatomic distances matching those expected for the coexistence of Cu and Na3Sb nanodomains. At 1 V charge, the structure somewhat differs from that of Cu2Sb whereas at 2 V charge, when all Na is removed, the structure is significantly closer to that of the starting material. 121Sb Mössbauer spectroscopy isomer shifts of Cu2Sb powder (-9.67 mm s-1) and thin films (-9.65 mm s-1) are reported for the first time, and agree with the value predicted theoretically. At full discharge, an isomer shift (-8.10 mm s-1) rather close to that of a Na3Sb reference powder (-8.00 mm s-1) is measured, in agreement with the formation of Na3Sb domains evidenced by XRD and XAS data. As a result, the isomer shift at 1 V charge (-9.29 mm s-1) is close to that of the pristine material and the higher value is in agreement with the lack of full desodiation at 1 V.« less

  3. Probing the Mechanism of Sodium Ion Insertion into Copper Antimony Cu2 Sb Anodes

    DOE PAGES [OSTI]

    Baggetto, Loïc; Carroll, Kyler J.; Hah, Hien-Yoong; Johnson, Charles E.; Mullins, David R.; Unocic, Raymond R.; Johnson, Jacqueline A.; Meng, Ying Shirley; Veith, Gabriel M.

    2014-03-25

    Cycling Cu2Sb films with fluoroethylene carbonate additive drastically improves the capacity retention of the electrode compared to cycling in pure PC with about 250 mAh g-1 retained capacity for about two hundred cycles. TEM photographs reveal that the pristine films are formed of nanoparticles of 5-20 nm diameters. XRD results highlight that during the first discharge the reaction leads to the formation of Na3Sb via an intermediate amorphous phase. During charge, Na3Sb crystallites convert into an amorphous phase, which eventually crystallizes into Cu2Sb at full charge, indicating a high degree of structural reversibility. The subsequent discharge is marked by amore » new plateau around 0.5 V at low Na/Sb content which does not correspond to the formation of a crystalline phase. XAS data show that the fully discharged electrode material has interatomic distances matching those expected for the coexistence of Cu and Na3Sb nanodomains. At 1 V charge, the structure somewhat differs from that of Cu2Sb whereas at 2 V charge, when all Na is removed, the structure is significantly closer to that of the starting material. 121Sb Mössbauer spectroscopy isomer shifts of Cu2Sb powder (-9.67 mm s-1) and thin films (-9.65 mm s-1) are reported for the first time, and agree with the value predicted theoretically. At full discharge, an isomer shift (-8.10 mm s-1) rather close to that of a Na3Sb reference powder (-8.00 mm s-1) is measured, in agreement with the formation of Na3Sb domains evidenced by XRD and XAS data. The isomer shift at 1 V charge (-9.29 mm s-1) is close to that of the pristine material and the higher value is in agreement with the lack of full desodiation at 1 V.« less

  4. Composition and grain size effects on the structural and mechanical properties of CuZr nanoglasses

    SciTech Connect

    Adibi, Sara [Institute of High Performance Computing, A*STAR, 138632 Singapore (Singapore); Mechanical Engineering Department, National University of Singapore, 117576 Singapore (Singapore); Branicio, Paulo S., E-mail: branicio@ihpc.a-star.edu.sg; Zhang, Yong-Wei [Institute of High Performance Computing, A*STAR, 138632 Singapore (Singapore); Joshi, Shailendra P., E-mail: Shailendra@nus.edu.sg [Mechanical Engineering Department, National University of Singapore, 117576 Singapore (Singapore)

    2014-07-28

    Nanoglasses (NGs), metallic glasses (MGs) with a nanoscale grain structure, have the potential to considerably increase the ductility of traditional MGs while retaining their outstanding mechanical properties. We investigated the effects of composition on the structural and mechanical properties of CuZr NG films with grain sizes between 3 to 15?nm using molecular dynamics simulations. Results indicate a transition from localized shear banding to homogeneous superplastic flow with decreasing grain size, although the critical average grain size depends on composition: 5?nm for Cu{sub 36}Zr{sub 64} and 3?nm for Cu{sub 64}Zr{sub 36}. The flow stress of the superplastic NG at different compositions follows the trend of the yield stress of the parent MG, i.e., Cu{sub 36}Zr{sub 64} yield/flow stress: 2.54?GPa/1.29?GPa and Cu{sub 64}Zr{sub 36} yield/flow stress: 3.57?GPa /1.58?GPa. Structural analysis indicates that the differences in mechanical behavior as a function of composition are rooted at the distinct statistics of prominent atomic Voronoi polyhedra. The mechanical behavior of NGs is also affected by the grain boundary thickness and the fraction of atoms at interfaces for a given average grain size. The results suggest that the composition dependence of the mechanical behavior of NGs follows that of their parent MGs, e.g., a stronger MG will generate a stronger NG, while the intrinsic tendency for homogeneous deformation occurring at small grain size is not affected by composition.

  5. Potassium-induced effect on structure and chemical activity of CuxO/Cu(111) (x≤2) surface: A combined scanning tunneling microscopy and density functional theory study

    SciTech Connect

    Liu, Ping; An, Wei; Stacchiola, Dario; Xu, Fang

    2015-10-16

    Potassium (K) plays an essential role in promoting catalytic reaction in many established industrial catalytic processes. Here, we report a combined study using scanning tunneling microscopy (STM) and density functional theory (DFT) in understanding the effect of depositing K on the atomic and electronic structures as well as chemical activities of CuxO/Cu(111) (x≤2). The DFT calculations observe a pseudomorphic growth of K on CuxO/Cu(111) up to 0.19 monolayer (ML) of coverage, where K binds the surface via strong ionic interaction with chemisorbed oxygen and the relatively weak electrostatic interactions with copper ions, lower and upper oxygen on the CuxO rings. The simulated STM pattern based on the DFT results agrees well with the experimental observations. The deposited K displays great impact on the surface electronic structure of CuxO/Cu(111), which induces significant reduction in work function and leads to a strong electron polarization on the surface. The promotion of K on the surface binding properties is selective. It varies depending on the nature of adsorbates. According to our results, K has little effect on surface acidity, while it enhances the surface basicity significantly. As a consequence, the presence of K does not help for CO adsorption on CuxO/Cu(111), but being able to accelerate the activation of CO2. Thus, such promotion strongly depends on the combinations from both geometric and electronic effects. Our results highlight the origin of promoting effect of alkalis in the design of catalysts for the complex reactions.

  6. Synthesis, crystal and electronic structure, and physical properties of the new lanthanum copper telluride La{sub 3}Cu{sub 5}Te{sub 7}

    SciTech Connect

    Zelinska, Mariya; Assoud, Abdeljalil [Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1 (Canada); Kleinke, Holger, E-mail: kleinke@uwaterloo.c [Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1 (Canada)

    2011-03-15

    The new lanthanum copper telluride La{sub 3}Cu{sub 5-x}Te{sub 7} has been obtained by annealing the elements at 1073 K. Single-crystal X-ray diffraction studies revealed that the title compound crystallizes in a new structure type, space group Pnma (no. 62) with lattice dimensions of a=8.2326(3) A, b=25.9466(9) A, c=7.3402(3) A, V=1567.9(1) A{sup 3}, Z=4 for La{sub 3}Cu{sub 4.86(4)}Te{sub 7}. The structure of La{sub 3}Cu{sub 5-x}Te{sub 7} is remarkably complex. The Cu and Te atoms build up a three-dimensional covalent network. The coordination polyhedra include trigonal LaTe{sub 6} prisms, capped trigonal LaTe{sub 7} prisms, CuTe{sub 4} tetrahedra, and CuTe{sub 3} pyramids. All Cu sites exhibit deficiencies of various extents. Electrical property measurements on a sintered pellet of La{sub 3}Cu{sub 4.86}Te{sub 7} indicate that it is a p-type semiconductor in accordance with the electronic structure calculations. -- Graphical abstract: Oligomeric unit comprising interconnected CuTe{sub 3} pyramids and CuTe{sub 4} tetrahedra. Display Omitted Research highlights: {yields} La{sub 3}Cu{sub 5-x}Te{sub 7} adopts a new structure type. {yields} All Cu sites exhibit deficiencies of various extents. {yields} The coordination polyhedra include trigonal LaTe{sub 6} prisms, capped trigonal LaTe{sub 7} prisms, CuTe{sub 4} tetrahedra and CuTe{sub 3} pyramids. {yields} La{sub 3}Cu{sub 5-x}Te{sub 7} is a p-type semiconductor.

  7. Electrodeposition, characterization and morphological investigations of NiFe/Cu multilayers prepared by pulsed galvanostatic, dual bath technique

    SciTech Connect

    Esmaili, S.; Bahrololoom, M.E.; Kavanagh, K.L.

    2011-02-15

    NiFe/Cu multilayers were grown sequentially by pulsed electrodeposition on copper (Cu) substrates. The layers were prepared in galvanostatic mode using a dual bath technique. The morphology, thickness, roughness and composition of the layers were studied using scanning electron microscopy, scanning transmission electron microscopy with energy dispersive X-ray spectroscopy, X-ray diffraction and atomic force microscopy. Analysis showed that the resulting multilayers were continuous layers with a root mean square roughness of 30 nm and a grain size of 20-60 nm. The Cu substrate and the electrodeposited Cu layer were preferentially (200) oriented while the NiFe layers were polycrystalline but with a preferred (200) texture. The thinnest multilayers produced were 20/40, NiFe/Cu, respectively. - Research Highlights: {yields} Thin MLs of Cu and Py can be ED utilizing a pulsed-galvanostatic, DBT. {yields} The resulting multilayers were continuous layers with an rms of 30 nm. {yields} The smallest average thickness achieved by DBT was 40 nm/20 nm for Cu/NiFe.

  8. CuCo2O4 ORR/OER Bi-functional catalyst: Influence of synthetic approach on performance

    DOE PAGES [OSTI]

    Serov, Alexey; Andersen, Nalin I.; Roy, Aaron J.; Matanovic, Ivana; Artyushkova, Kateryna; Atanassov, Plamen

    2015-02-07

    A series of CuCo2O4 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 CuCo2O4 and it was found that CuCo2O4 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 methodmore » (SSM) catalyst has the highest performance in both ORR and OER and has the highest content of phase-pure CuCo2O4. 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 (E1/2) of CuCo2O4-SSM was found as 0.8 V, making this material a state-of-the-art, unsupported oxide catalyst.« less

  9. Application of glucose as a green capping agent and reductant to fabricate CuI micro/nanostructures

    SciTech Connect

    Tavakoli, Farnosh; Salavati-Niasari, Masoud; Ghanbari, Davood; Saberyan, Kamal; Hosseinpour-Mashkani, S. Mostafa

    2014-01-01

    Graphical abstract: - Highlights: • CuI nanostructures were prepared via a simple precipitation method. • Glucose as a green capping agent and reductant was applied. • The effect of glucose concentration on the morphology of CuI was investigated. • According to XRD results, pure cubic phase CuI have been formed by using glucose. - Abstract: In this work, CuI micro/nanostructures have been successfully prepared via a simple precipitation route at room temperature. By using glucose as a clean reducing agent with different concentrations, CuI micro/nanostructures with various morphologies were obtained. Besides glucose, Na{sub 2}SO{sub 3}, KBH{sub 4} and N{sub 2}H{sub 4}·H{sub 2}O have been applied as reductant. X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence spectroscopy, X-ray energy dispersive spectroscopy (EDS) and Fourier transformed infrared (FT-IR) spectroscopy were used to characterize the as-produced CuI micro/nanostructures. According to the XRD results, it was found that pure cubic phase CuI have been formed by using glucose.

  10. Chemical stability of highly (0001) textured Sm(CoCu){sub 5} thin films with a thin Ta capping layer

    SciTech Connect

    Zhao Haibao; Wang Hao; Liu Xiaoqi; Wang Jianping; Zhang Tao

    2011-04-01

    With the highest magnetocrystalline anisotropy constant (Ku) among practical magnetic materials, SmCo{sub 5} could be a very attractive candidate for future high areal density magnetic recording. However, its corrosion resistance is always a concern in recording media applications. In this paper, the chemical stability and microstructures of highly (0001) textured Sm(CoCu){sub 5} thin films with and without a 3 nm Ta capping layer were reported. For Sm(CoCu){sub 5} thin films without a capping layer, the coercivity decreases significantly (from 8kOe to 1kOe) within one month. Sm(CoCu){sub 5} thin films capped with a thin Ta layer (3 nm) behave differently. Even exposed to a laboratory environment (25 deg. C) over 3 years, the Ta-capped Sm(CoCu){sub 5} thin films are stable in terms of structural and magnetic properties, i.e., there were no changes in X-ray diffraction peaks and vibrating sample magnetometer hysteresis loops. Microstructure of Ta-capped Sm(CoCu){sub 5} thin films showed that Sm(CoCu){sub 5} formed a domelike particle assembly structure on a smooth Ru underlayer and were well covered by partially oxidized Ta capping layer, as shown by TEM cross-section micrographs. Accelerated corrosion treatment (130 deg. C, 95% relative humidity, 6 h) was performed on Ta-capped Sm(CoCu){sub 5} thin films. X-ray photoelectron spectroscopy (XPS) results showed that no Co was detected on the sample surface before the corrosion treatment, but strong XPS signals of CoOx and Co(OH)x were observed after treatment. Therefore, none of our Sm(CoCu){sub 5} thin films can pass the accelerated corrosion test. Hcp-phased CoPt-alloys are proposed as better capping materials for Sm(CoCu){sub 5} thin films in future high-density magnetic recording applications.

  11. FePtCu alloy thin films: Morphology, L1{sub 0} chemical ordering, and perpendicular magnetic anisotropy

    SciTech Connect

    Brombacher, C.; Schletter, H.; Daniel, M.; Matthes, P.; Joehrmann, N.; Makarov, D.; Hietschold, M.; Albrecht, M.; Maret, M.

    2012-10-01

    Rapid thermal annealing was applied to transform sputter-deposited Fe{sub 51}Pt{sub 49}/Cu bilayers into L1{sub 0} chemically ordered ternary (Fe{sub 51}Pt{sub 49}){sub 100-x}Cu{sub x} alloys with (001) texture on amorphous SiO{sub 2}/Si substrates. It was found that for thin film samples, which were processed at 600 Degree-Sign C for 30 s, the addition of Cu strongly favors the L1{sub 0} ordering and (001) texture formation. Furthermore, it could be revealed by transmission electron microscopy and electron backscatter diffraction that the observed reduction of the ordering temperature with Cu content is accompanied by an increased amount of nucleation sites forming L1{sub 0} ordered grains. The change of the structural properties with Cu content and annealing temperature is closely related to the magnetic properties. While an annealing temperature of 800 Degree-Sign C induces strong perpendicular magnetic anisotropy (PMA) in binary Fe{sub 51}Pt{sub 49} films, the addition of Cu systematically reduces the PMA. However, due to the enhancement of both the A1-L1{sub 0} phase transformation and the development of the (001) texture with increasing Cu content, lowering of the annealing temperature leads to a shift of the maximum perpendicular magnetic anisotropy towards alloys with higher Cu content. Thus, for an annealing temperature of 600 Degree-Sign C, the highest perpendicular magnetic anisotropy energy is found for the (Fe{sub 51}Pt{sub 49}){sub 91}Cu{sub 9} alloy. The smooth surface morphology, adjustable PMA, and high degree of intergranular exchange coupling make these films suitable for post-processing required for specific applications such as for sensorics or magnetic data storage.

  12. Synthesis and Evaluation of Cu/SAPO-34 Catalysts for NH3-SCR 2: Solid-state Ion Exchange and One-pot Synthesis

    SciTech Connect

    Gao, Feng; Walter, Eric D.; Washton, Nancy M.; Szanyi, Janos; Peden, Charles HF

    2015-01-01

    Cu-SAPO-34 catalysts are synthesized using two methods: solid-state ion exchange (SSIE) and one-pot synthesis. SSIE is conducted by calcining SAPO-34/CuO mixtures at elevated temperatures. For the one-pot synthesis method, Cu-containing chemicals (CuO and CuSO4) are added during gel preparation. A high-temperature calcination step is also needed for this method. Catalysts are characterized with surface area/pore volume measurements, temperature programmed reduction (TPR), electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopies, and scanning electron microscopy (SEM). Catalytic properties are examined using standard ammonia selective catalytic reduction (NH3-SCR) and ammonia oxidation reactions. In Cu-SAPO-34 samples formed using SSIE, Cu presents both as isolated Cu2+ ions and unreacted CuO. The former is highly active and selective in NH3-SCR, while the latter catalyzes a side reaction; notably, the non-selective oxidation of NH3 above 350 ºC. Using the one-pot method followed by a high-temperature aging treatment, it is possible to form Cu SAPO-34 samples with predominately isolated Cu2+ ions at low Cu loadings. However at much higher Cu loadings, isolated Cu2+ ions that bind weakly with the CHA framework and CuO clusters also form. These Cu moieties are very active in catalyzing non-selective NH3 oxidation above 350 ºC. Low-temperature reaction kinetics indicate that Cu-SAPO-34 samples formed using SSIE have core-shell structures where Cu is enriched in the shell layers; while Cu is more evenly distributed within the one-pot samples. Reaction kinetics also suggest that at low temperatures, the local environment next to Cu2+ ion centers plays little role on the overall catalytic properties. The authors gratefully acknowledge the US Department of Energy (DOE), Energy Efficiency and Renewable Energy, Vehicle Technologies Office for the support of this work. The research described in this paper was performed at the Environmental

  13. Devitrification kinetics and phase selection mechanisms in Cu-Zr metallic glasses

    SciTech Connect

    Kalay, Ilkay

    2010-12-15

    Metallic glasses have been a promising class of materials since their discovery in the 1960s. Indeed, remarkable chemical, mechanical and physical properties have attracted considerable attention, and several excellent reviews are available. Moreover, the special group of glass forming alloys known as the bulk metallic glasses (BMG) become amorphous solids even at relatively low cooling rates, allowing them to be cast in large cross sections, opening the scope of potential applications to include bulk forms and net shape structural applications. Recent studies have been reported for new bulk metallic glasses produced with lower cooling rates, from 0.1 to several hundred K/s. Some of the application products of BMGs include sporting goods, high performance springs and medical devices. Several rapid solidification techniques, including melt-spinning, atomization and surface melting have been developed to produce amorphous alloys. The aim of all these methods is to solidify the liquid phase rapidly enough to suppress the nucleation and growth of crystalline phases. Furthermore, the production of amorphous/crystalline composite (ACC) materials by partial crystallization of amorphous precursor has recently given rise to materials that provide better mechanical and magnetic properties than the monolithic amorphous or crystalline alloys. In addition, these advances illustrate the broad untapped potential of using the glassy state as an intermediate stage in the processing of new materials and nanostructures. These advances underlie the necessity of investigations on prediction and control of phase stability and microstructural dynamics during both solidification and devitrification processes. This research presented in this dissertation is mainly focused on Cu-Zr and Cu-Zr-Al alloy systems. The Cu-Zr binary system has high glass forming ability in a wide compositional range (35-70 at.% Cu). Thereby, Cu-Zr based alloys have attracted much attention according to fundamental

  14. Method for preparation of textured YBa.sub.2 Cu.sub.3 O.sub.x superconductor

    DOEpatents

    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 .

  15. Cation Ratio Fluctuations in Cu2ZnSnS4 at the 20 nm Length Scale

    Office of Scientific and Technical Information (OSTI)

    Investigated by Analytical Electron Microscopy (Journal Article) | SciTech Connect Cation Ratio Fluctuations in Cu2ZnSnS4 at the 20 nm Length Scale Investigated by Analytical Electron Microscopy Citation Details In-Document Search Title: Cation Ratio Fluctuations in Cu2ZnSnS4 at the 20 nm Length Scale Investigated by Analytical Electron Microscopy Kesterite Cu2ZnSn(S,Se)4 (CZTSSe) is a sustainable material for thin-film photovoltaics with device efficiencies greater than 12% have been

  16. Preparation and thermoelectric properties of ternary superionic conductor CuCrS{sub 2}

    SciTech Connect

    Chen Yuexing; Zhang Boping; Ge Zhenhua; Shang Pengpeng

    2012-02-15

    Transition metal chalcogenide CuCrS{sub 2} powder was synthesized by mechanical alloying (MA) and then consolidated by spark plasma sintering (SPS) technique at 673-1073 K. The phase structure, microstructure and thermoelectric properties of samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and Seebeck coefficient/electrical conductivity measuring system, respectively. All the bulks indicated a single phase CuCrS{sub 2}, while the high relative density over 90% were attained for the samples sintered at 873-1073 K. The electrical conductivity of bulk samples displayed a typical characteristic of semiconductor. With increasing measuring temperature, the conductive behaviour of bulk samples sintered over 973 K showed a semiconductor transformation from n-type to p-type due to the changes of main carrier type. The sample obtained by applying SPS at 873 K got the highest power factor 83.2 {mu}W m{sup -1} K{sup -2}, and the largest ZT value 0.11 at 673 K. - Graphical abstract: The samples sintered above 873 K, both of the Seebeck coefficient and electrical conductivity exhibit an increase tendency with increasing temperature, which is due to the mechanism of mix-conduction for CuCrS{sub 2}. Highlights: Black-Right-Pointing-Pointer Single phase CuCrS{sub 2} powder was synthesized by ball-milling at 425 rpm for 40 h. Black-Right-Pointing-Pointer Dense CuCrS{sub 2} bulks were fabricated using SPS techniques at sintering temperature 873-1073 K. Black-Right-Pointing-Pointer Seebeck coefficient of CuCrS{sub 2} samples sintered over 973 K change the signs. Black-Right-Pointing-Pointer Highest power factor reached 83.2 {mu}W m{sup -1} K{sup -2} at 673 K for the sample sintered at 873 K. Black-Right-Pointing-Pointer ZT value was 0.11 at 673 K for the sample sintered at 873 K.

  17. Pulse studies to decipher the role of surface morphology in CuO/CeO₂ nanocatalysts for the water gas shift reaction

    DOE PAGES [OSTI]

    Rodriguez, Jose A.; Zhao, Fuzhen; Liu, Zongyuan; Xu, Wenqian; Yao, Siyu; Si, Rui; Johnston-Peck, Aaron C.; Martinez-Arias, Arturo; Hanson, Jonathan C.; Senanayake, Sanjaya D.

    2015-01-23

    The water-gas shift reaction (WGS, CO + H₂O → CO₂) was studied over CuO/CeO₂ catalysts with two different ceria particle morphohologies, in the form of nanospheres (ns) and nanocubes (nc). To understand the strong dependence of the WGS reaction activity on the ceria nanoshapes, pulses of CO (without and with water vapor) were employed during in situ X-ray diffraction (XRD) and X-ray absoprtion near edge structure (XANES) measurements done to characterize the catalysts. The results showed that CuO/CeO₂ (ns) exhibited a substantially better activity than CuO/CeO₂ (nc). The higher activity was associated with the unique properties of CuO/CeO₂ (ns), suchmore » as the easier reduction of highly dispersed CuO to metallic Cu, the stability of metallic Cu and a larger concentration Ce³⁺ in CeO₂ (ns).« less

  18. Effects of substrate temperature and Cu underlayer thickness on the formation of SmCo{sub 5}(0001) epitaxial thin films

    SciTech Connect

    Ohtake, Mitsuru; Nukaga, Yuri; Futamoto, Masaaki; Kirino, Fumiyoshi

    2010-05-15

    SmCo{sub 5}(0001) epitaxial thin films were prepared on Cu(111) underlayers heteroepitaxially grown on Al{sub 2}O{sub 3}(0001) single-crystal substrates by molecular beam epitaxy. The effects of substrate temperature and Cu underlayer thickness on the crystallographic properties of SmCo{sub 5}(0001) epitaxial films were investigated. The Cu atoms of underlayer diffuse into the SmCo{sub 5} film and substitute the Co sites in SmCo{sub 5} structure forming an alloy compound of Sm(Co,Cu){sub 5}. The ordered phase formation is enhanced with increasing the substrate temperature and with increasing the Cu underlayer thickness. The Cu atom diffusion into the SmCo{sub 5} film is assisting the formation of Sm(Co,Cu){sub 5} ordered phase.

  19. Pulse studies to decipher the role of surface morphology in CuO/CeO₂ nanocatalysts for the water gas shift reaction

    SciTech Connect

    Rodriguez, Jose A.; Zhao, Fuzhen; Liu, Zongyuan; Xu, Wenqian; Yao, Siyu; Si, Rui; Johnston-Peck, Aaron C.; Martinez-Arias, Arturo; Hanson, Jonathan C.; Senanayake, Sanjaya D.

    2015-01-23

    The water-gas shift reaction (WGS, CO + H₂O → CO₂) was studied over CuO/CeO₂ catalysts with two different ceria particle morphohologies, in the form of nanospheres (ns) and nanocubes (nc). To understand the strong dependence of the WGS reaction activity on the ceria nanoshapes, pulses of CO (without and with water vapor) were employed during in situ X-ray diffraction (XRD) and X-ray absoprtion near edge structure (XANES) measurements done to characterize the catalysts. The results showed that CuO/CeO₂ (ns) exhibited a substantially better activity than CuO/CeO₂ (nc). The higher activity was associated with the unique properties of CuO/CeO₂ (ns), such as the easier reduction of highly dispersed CuO to metallic Cu, the stability of metallic Cu and a larger concentration Ce³⁺ in CeO₂ (ns).

  20. Characterization and oxidation states of Cu and Pd in Pd?CuO/ZnO/ZrO[subscript 2] catalysts for hydrogen production by methanol partial oxidation

    SciTech Connect

    Schuyten, S.; Guerrero, S.; Miller, J.T.; Shibatae, T.; Wolf, E.E.

    2009-01-30

    Copper and zinc oxide based catalysts prepared by coprecipitation were promoted with palladium and ZrO{sub 2}, and their activity and selectivity for methanol oxidative reforming was measured and characterized by N{sub 2}O decomposition, X-ray absorption spectroscopy, BET, X-ray photoelectron spectroscopy, X-ray diffraction, and temperature programmed reduction. Addition of ZrO{sub 2} increased copper dispersion and surface area, with little effect on activity, while palladium promotion significantly enhanced activity with little change of the catalytic structure. A catalyst promoted with both ZrO{sub 2} and palladium yielded hydrogen below 150 C. EXAFS results under reaction conditions showed that the oxidation state of copper was influenced by palladium in the catalyst bulk. A palladium promoted catalyst contained 90% Cu{sup 0}, while the copper in an unpromoted catalyst was 100% Cu{sup 1+} at the same temperature. Palladium preferentially forms an unstable alloy with copper instead of zinc during reduction, which persists during reaction regardless of copper oxidation state. A 100-h time on stream activity measurement showed growth in copper crystallites and change in copper oxidation state resulting in decreasing activity and selectivity. A kinetic model of the reaction pathway showed that palladium and ZrO{sub 2} promoters lower the activation energy of methanol combustion and steam reforming reactions.

  1. Effects of alternating seawater flow and stagnant layup conditions on the general and localized corrosion resistance of CuNi and NiCu alloys in marine service

    SciTech Connect

    Kain, R.M.; Weber, B.E.

    1997-12-01

    From time-to-time seawater handling systems are subjected to lay-up which can produce chemical and biological changes, and conceivably alter the corrosion resistance of metals used in piping and other equipment. In the case of reverse osmosis/membrane technology type desalination equipment, sanitizing agents may be introduced after draining. Simulation tests were conducted to determine any effect of a bisulfite sanitizing treatment when used between periods of normal seawater flow. Corresponding tests were conducted with lay-up comprising non-refreshed seawater which ultimately stagnated. Test results for CuNi alloy C71500 indicted that repeated cycling between seawater exposure and bisulfite treatments was detrimental in reducing that alloy`s resistance to general corrosion, and to a lesser degree its crevice corrosion resistance. The typical pitting and crevice corrosion behavior of NiCu alloy N04400, found upon exposure to slowly moving, aerated seawater was neither diminished or accelerated by cyclic lay-up with either stagnant seawater or the candidate bisulfite-containing solution. However, some increase in general corrosion was observed.

  2. The spin-dependent transport of Co-encapsulated Si nanotubes contacted with Cu electrodes

    SciTech Connect

    Guo, Yan-Dong; Yan, Xiao-Hong; Xiao, Yang

    2014-02-10

    Unlike carbon nanotubes, silicon ones are hard to form. However, they could be stabilized by metal-encapsulation. Using first-principles calculations, we investigate the spin-dependent electronic transport of Co-encapsulated Si nanotubes, which are contacted with Cu electrodes. For the finite tubes, as the tube-length increases, the transmission changes from spin-unpolarized to spin-polarized. Further analysis shows that, not only the screening of electrodes on Co's magnetism but also the spin-asymmetric Co-Co interactions are the physical mechanisms. As Cu and Si are the fundamental elements in semiconductor industry, our results may throw light on the development of silicon-based spintronic devices.

  3. Multilayered Al/CuO thermite formation by reactive magnetron sputtering: Nano versus micro

    SciTech Connect

    Petrantoni, M.; Rossi, C.; Salvagnac, L.; Conedera, V.; Esteve, A.; Tenailleau, C.; Alphonse, P.; Chabal, Y. J.

    2010-10-15

    Multilayered Al/CuO thermite was deposited by a dc reactive magnetron sputtering method. Pure Al and Cu targets were used in argon-oxygen gas mixture plasma and with an oxygen partial pressure of 0.13 Pa. The process was designed to produce low stress (<50 MPa) multilayered nanoenergetic material, each layer being in the range of tens nanometer to one micron. The reaction temperature and heat of reaction were measured using differential scanning calorimetry and thermal analysis to compare nanostructured layered materials to microstructured materials. For the nanostructured multilayers, all the energy is released before the Al melting point. In the case of the microstructured samples at least 2/3 of the energy is released at higher temperatures, between 1036 and 1356 K.

  4. Crystallization from high temperature solutions of Si in Cu/Al solvent

    DOEpatents

    Ciszek, Theodore F.; Wang, Tihu

    1996-01-01

    A liquid phase epitaxy method for forming thin crystalline layers of device quality silicon having less than 3.times.10.sup.16 Cu atoms/cc impurity, comprising: preparing a saturated liquid solution of Si in a Cu/Al solvent at about 20 to about 40 at. % Si at a temperature range of about 850.degree. to about 1100.degree. C. in an inert gas; immersing or partially immersing a substrate in the saturated liquid solution; super saturating the solution by lowering the temperature of the saturated solution; holding the substrate in the saturated solution for a period of time sufficient to cause Si to precipitate out of solution and form a crystalline layer of Si on the substrate; and withdrawing the substrate from the solution.

  5. Crystallization from high temperature solutions of Si in Cu/Al solvent

    DOEpatents

    Ciszek, T.F.; Wang, T.

    1996-08-13

    A liquid phase epitaxy method is disclosed for forming thin crystalline layers of device quality silicon having less than 3{times}10{sup 16} Cu atoms/cc impurity, comprising: preparing a saturated liquid solution of Si in a Cu/Al solvent at about 20 to about 40 at. % Si at a temperature range of about 850 to about 1100 C in an inert gas; immersing or partially immersing a substrate in the saturated liquid solution; super saturating the solution by lowering the temperature of the saturated solution; holding the substrate in the saturated solution for a period of time sufficient to cause Si to precipitate out of solution and form a crystalline layer of Si on the substrate; and withdrawing the substrate from the solution. 3 figs.

  6. Deformation behavior of Nb nanowires in TiNiCu shape memory alloy matrix

    DOE PAGES [OSTI]

    Jiang, Daqiang; Liu, Yinong; Yu, Cun; Liu, Weilong; Yang, Hong; Jiang, Xiaohua; Ren, Yang; Cui, Lishan

    2015-08-18

    An in-situ nanowire Nb/TiNiCu composite is fabricated based on the concept of strain under-matching between a phase transforming matrix and high strength nanomaterials. The deformation behavior of the Nb nanowire was investigated by means of in-situ synchrotron X-ray diffraction when the TiNiCu matrix underwent different deformation modes. The maximum lattice strain of the Nb nanowires was about 5% when the matrix deformed via martensitic transformation or 1% when deforming plastically by dislocation slip. As a result, the Nb nanowires showed a lattice strain of 3.5% when the matrix deformed in the mixed mode of plastic deformation and martensitic transformation, whichmore » means that the occurrence of plastic deformation does not impede load transfer from the matrix to the nanowires.« less

  7. Unique properties of CuZrAl bulk metallic glasses induced by microalloying

    SciTech Connect

    Huang, B.; Bai, H. Y.; Wang, W. H.

    2011-12-15

    We studied the glass forming abilities (GFA), mechanical, and physical properties of (CuZr){sub 92.5}Al{sub 7}X{sub 0.5} (X = La, Sm, Ce, Gd, Ho, Y, and Co) bulk metallic glasses (BMGs). We find that the GFA, mechanical, and physical properties can be markedly changed and modulated by the minor rare earth addition. The Kondo screening effect is found to exist in (CuZr){sub 92.5}Al{sub 7}Ce{sub 0.5} BMG at low temperatures and the Schottky effect exists in all the rare earth element doped BMGs. Our results indicate that the minor addition is an effective way for modulating and getting desirable properties of the BMGs. The mechanisms of the effects of the addition are discussed. The results have implications for the exploration of metallic glasses and for improving the mechanical and low temperature physical properties of BMGs.

  8. Single crystal growth and characterization of the large-unit-cell compound Cu13Ba

    SciTech Connect

    Jesche, Anton; Budko, Serguei L.; Canfield, Paul C.

    2013-10-31

    Single crystals of Cu13Ba were successfully grown out of BaCu self flux. Temperature dependent magnetization, M (T ), electrical resistivity, ?(T)?(T), and specific heat, Cp(T)Cp(T), data are reported. Isothermal magnetization measurements, M(H)M(H), show clear de Haas-van Alphen oscillations at T = 2 K for applied fields as low as View the MathML source?0H=1T. An anomalous behavior of the magnetic susceptibility is observed up to T ? 50 K reflecting the effect of de Haas-van Alphen oscillations at fairly high temperatures. The field- and temperature-dependencies of the magnetization indicate the presence of diluted magnetic impurities with a concentration of the order of 0.01 at.%. Accordingly, the minimum and lower temperature rise observed in the electrical resistivity at and below T = 15 K is attributed to the Kondo-impurity effect.

  9. Structural and dielectric properties of CuO-doped SrTiO{sub 3} ceramics

    SciTech Connect

    Naidu, K. Chandra Babu Sarmash, T. Sofi; Maddaiah, M.; Reddy, V. Narasimha; Subbarao, T.

    2015-06-24

    Copper-doped SrTiO{sub 3} (ST) ceramic powders were processed by solid-state route diffusion (SRD) bulk preparation technique. We reported the effect of Cu{sup +2} ions on the dielectric response of ST and it established the substantial increase in dielectric constant (ε{sub r}) than undoped ST from 303K-673K and low loss (tanδ) for good dielectric applications. In respect of the electrical properties ac- activation energies were computed of range 0.089-0.319eV using lnσ Vs 1/T plots. The microstructure was examined with grain sizes 6-9µm of uniform distribution by field emission scanning electron microscope (FESEM). Some additional phases SrCu{sub 3}Ti{sub 4}O{sub 12} and TiO{sub 2} rutiles were detected by X-ray diffraction technique.

  10. Deformation behavior of Nb nanowires in TiNiCu shape memory alloy matrix

    SciTech Connect

    Jiang, Daqiang; Liu, Yinong; Yu, Cun; Liu, Weilong; Yang, Hong; Jiang, Xiaohua; Ren, Yang; Cui, Lishan

    2015-08-18

    An in-situ nanowire Nb/TiNiCu composite is fabricated based on the concept of strain under-matching between a phase transforming matrix and high strength nanomaterials. The deformation behavior of the Nb nanowire was investigated by means of in-situ synchrotron X-ray diffraction when the TiNiCu matrix underwent different deformation modes. The maximum lattice strain of the Nb nanowires was about 5% when the matrix deformed via martensitic transformation or 1% when deforming plastically by dislocation slip. As a result, the Nb nanowires showed a lattice strain of 3.5% when the matrix deformed in the mixed mode of plastic deformation and martensitic transformation, which means that the occurrence of plastic deformation does not impede load transfer from the matrix to the nanowires.

  11. Effective activation energy in the Bi-Sr-Ca-Cu-O systems

    SciTech Connect

    Sengupta, S.; Shi, D.; Wang, Z.; Smith, M.; McGinn, P.J.

    1992-08-01

    Magnetic relaxation in the Bi-Sr-Ca-Cu-O systems has been investigated in a wide temperature regime. Previously reported studies of the effective activation energy, U, have been controversial in terms of temperature and field dependence of the critical current density, j{sub c}. We have considered the temperature dependence of j{sub c} and constructed the U-j (or M) curves for the Bi-Sr-Ca-Cu-O system. We found that at a constant driving force and temperature, U is considerably higher for 2245 samples than for 2223 samples. This enhancement can be attributed to the flux pinning from finely dispersed calcium- and copper- rich precipitates.

  12. Solidification analysis of a centrifugal atomizer using the Al-32.7wt.% Cu alloy

    SciTech Connect

    Osborne, M.G.

    1998-02-23

    A centrifugal atomizer (spinning disk variety) was designed and constructed for the production of spherical metal powders, 100--1,000 microns in diameter in an inert atmosphere. Initial atomization experiments revealed the need for a better understanding of how the liquid metal was atomized and how the liquid droplets solidified. To investigate particle atomization, Ag was atomized in air and the process recorded on high-speed film. To investigate particle solidification, Al-32.7 wt.% Cu was atomized under inert atmosphere and the subsequent particles were examined microscopically to determine solidification structure and rate. This dissertation details the experimental procedures used in producing the Al-Cu eutectic alloy particles, examination of the particle microstructures, and determination of the solidification characteristics (e.g., solidification rate) of various phases. Finally, correlations are proposed between the operation of the centrifugal atomizer and the observed solidification spacings.

  13. Effective activation energy in the Bi-Sr-Ca-Cu-O systems

    SciTech Connect

    Sengupta, S.; Shi, D.; Wang, Z.; Smith, M. ); McGinn, P.J. . Dept. of Electrical Engineering)

    1992-08-01

    Magnetic relaxation in the Bi-Sr-Ca-Cu-O systems has been investigated in a wide temperature regime. Previously reported studies of the effective activation energy, U, have been controversial in terms of temperature and field dependence of the critical current density, j[sub c]. We have considered the temperature dependence of j[sub c] and constructed the U-j (or M) curves for the Bi-Sr-Ca-Cu-O system. We found that at a constant driving force and temperature, U is considerably higher for 2245 samples than for 2223 samples. This enhancement can be attributed to the flux pinning from finely dispersed calcium- and copper- rich precipitates.

  14. Synthesis, characterization and physical properties of Al-Cu-Fe quasicrystalline plasma sprayed coatings

    SciTech Connect

    Daniel, S.

    1995-11-09

    Our lab has been working with plasma spraying of both high pressure gas atomized (HPGA) and cast and crushed quasicrystal powders. A major component of this research includes comparative studies of PAS coatings formed with starting powders prepared by both techniques. In addition, a thorough investigation of the effects of starting powder particle size on coating microstructure is included. During the course of the overall research, an interest developed in forming Al-Cu-Fe materials with finer grain sizes. Therefore, a brief study was performed to characterize the effect of adding boron to Al-Cu-Fe materials prepared by different techniques. In addition to characterizing the microstructural features of the above materials, oxidation and wear behavior was also examined.

  15. Enhanced Thermoelectric Properties of Cu2ZnSnSe4 with Ga-doping

    DOE PAGES [OSTI]

    Wei, Kaya; Beauchemin, Laura; Wang, Hsin; Porter, Wallace D.; Martin, Joshua; Nolas, George S.

    2015-08-10

    Gallium doped Cu2ZnSnSe4 quaternary chalcogenides with and without excess Cu were synthesized by elemental reaction and densified using hot pressing in order to investigate their high temperature thermoelectric properties. The resistivity, , and Seebeck coefficient, S, for these materials decrease with increased Ga-doping while both mobility and effective mass increase with Ga doping. The power factor (S2/ρ) therefore increases with Ga-doping. The highest thermoelectric figure of merit (ZT = 0.39 at 700 K) was obtained for the composition that had the lowest thermal conductivity. Our results suggest an approach to achieving optimized thermoelectric properties and are part of the continuingmore » effort to explore different quaternary chalcogenide compositions and structure types, as this class of materials continues to be of interest for thermoelectrics applications.« less

  16. Magnetic properties and Fermi surface of antiferromagnetic SmCu sub 6

    SciTech Connect

    Onuki, Y.; Umezawa, A.; Kwok, W.K.; Crabtree, G.W. ); Nishihara, M.; Ina, K.; Yamazaki, T.; Omi, T.; Komatsubara, T. ); Maezawa, K.; Wakabayashi, S. ); Takayanagi, S. ); Wada, N. )

    1990-01-01

    We report measurements of the magnetic susceptibility, specific heat, magnetoresistance, Hall effect, and Fermi surface in SmCu{sub 6}. The susceptibility follows the Van Vleck form for Sm{sup 3+} near room temperature and shows two antiferromagnetic phase transitions at 9.6 and 5.2 K. The specific heat implies a quartet ground state for the crystal-field-split {ital J}=5/2 angular momentum state. Magnetoresistance indicates that SmCu{sub 6} contains both electron and hole carriers but is uncompensated. de Haas--van Alphen measurements show that the Fermi surface in the antiferromagnetic state consists of a network of cylinders oriented 30{degree} from the {ital b} and {ital c} axes.

  17. Itinerant magnetism in metallic CuFe2Ge2

    SciTech Connect

    Shanavas, K. V.; Singh, David J.; He, Ruihua

    2015-03-25

    Theoretical calculations are performed to understand the electronic structure and magnetic properties of CuFe2Ge2. The band structure reveals large electron density N(EF) at the Fermi level suggesting a strong itinerant character of magnetism. The Fermi surface is dominated by two dimensional sheet like structures, with potentially strong nesting between them. The magnetic ground state appears to be ferromagnetic along a and antiferromagnetic in other directions. The results show that CuFe2Ge2 is an antiferromagnetic metal, with similarities to the Fe-based superconductors; such as magnetism with substantial itinerant character and coupling between magnetic order and electrons at the Fermi energy.

  18. Effects of charge inhomogeneities on elementary excitations in La2-xSrxCuO₄

    DOE PAGES [OSTI]

    Park, S. R.; Hamann, A.; Pintschovius, L.; Lamago, D.; Khaliullin, G.; Fujita, M.; Yamada, K.; Gu, G. D.; Tranquada, J. M.; Reznik, D.

    2011-12-12

    Purely local experimental probes of many copper oxide superconductors show that their electronic states are inhomogeneous in real space. For example, scanning tunneling spectroscopic imaging shows strong variations in real space, and according to nuclear quadrupole resonance (NQR) studies, the charge distribution in the bulk varies on the nanoscale. However, the analysis of the experimental results utilizing spatially averaged probes often ignores this fact. We have performed a detailed investigation of the doping dependence of the energy and linewidth of the zone-boundary Cu-O bond-stretching vibration in La2-xSrxCuO₄ by inelastic neutron scattering. Both our results as well as previously reported angle-dependentmore » momentum widths of the electronic spectral function detected by angle-resolved photoemission can be reproduced by including the same distribution of local environments extracted from the NQR analysis.« less

  19. Density-functional Monte-Carlo simulation of CuZn order-disorder transition

    DOE PAGES [OSTI]

    Khan, Suffian N.; Eisenbach, Markus

    2016-01-25

    We perform a Wang-Landau Monte Carlo simulation of a Cu0.5Zn0.5 order-disorder transition using 250 atoms and pairwise atom swaps inside a 5 x 5 x 5 BCC supercell. Each time step uses energies calculated from density functional theory (DFT) via the all-electron Korringa-Kohn- Rostoker method and self-consistent potentials. Here we find CuZn undergoes a transition from a disordered A2 to an ordered B2 structure, as observed in experiment. Our calculated transition temperature is near 870 K, comparing favorably to the known experimental peak at 750 K. We also plot the entropy, temperature, specific-heat, and short-range order as a function ofmore » internal energy.« less

  20. Computer modeling of Y-Ba-Cu-O thin film deposition and growth

    SciTech Connect

    Burmester, C.; Gronsky, R. ); Wille, L. . Dept. of Physics)

    1991-07-01

    The deposition and growth of epitaxial thin films of YBa{sub 2}Cu{sub 3}O{sub 7} are modeled by means of Monte Carlo simulations of the deposition and diffusion of Y, Ba, and Cu oxide particles. This complements existing experimental characterization techniques to allow the study of kinetic phenomena expected to play a dominant role in the inherently non-equilibrium thin film deposition process. Surface morphologies and defect structures obtained in the simulated films are found to closely resemble those observed experimentally. A systematic study of the effects of deposition rate and substrate temperature during in-situ film fabrication reveals that the kinetics of film growth can readily dominate the structural formation of the thin film. 16 refs., 4 figs.

  1. Structural, elastic, electronic, magnetic and vibrational properties of CuCoMnGa under pressure

    SciTech Connect

    İyigör, Ahmet; Uğur, Şule

    2014-10-06

    First principles calculations for the structural, electronic, elastic and phonon properties of the cubic quaternary heusler alloy CuCoMnGa on pressure have been reported by density functional theory (DFT) within generalized gradient approximation (GGA). The calculated values of the elastic constants were used for estimations of the Debye temperatures, the bulk modulus, the shear modulus, the young modulus E, the poisson's ratio σ and the B/G ratio. The elastic constants satisfy all of the mechanical stability criteria. The electronic structures of the ferromagnetic configuration for CuCoMnGa have a metallic character. The estimated magnetic moment per formula unit is 3.76 μ{sub B}. The phonon dispersion is studied using the supercell approach, and the stable nature at 0.2 GPa pressure is observed.

  2. 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

    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.}

  3. Thermoelectric and mechanical properties of spark plasma sintered Cu{sub 3}SbSe{sub 3} and Cu{sub 3}SbSe{sub 4}: Promising thermoelectric materials

    SciTech Connect

    Tyagi, Kriti; Gahtori, Bhasker; Bathula, Sivaiah; Toutam, Vijaykumar; Sharma, Sakshi; Singh, Niraj Kumar; Dhar, Ajay

    2014-12-29

    We report the synthesis of thermoelectric compounds, Cu{sub 3}SbSe{sub 3} and Cu{sub 3}SbSe{sub 4}, employing the conventional fusion method followed by spark plasma sintering. Their thermoelectric properties indicated that despite its higher thermal conductivity, Cu{sub 3}SbSe{sub 4} exhibited a much larger value of thermoelectric figure-of-merit as compared to Cu{sub 3}SbSe{sub 3}, which is primarily due to its higher electrical conductivity. The thermoelectric compatibility factor of Cu{sub 3}SbSe{sub 4} was found to be ∼1.2 as compared to 0.2 V{sup −1} for Cu{sub 3}SbSe{sub 3} at 550 K. The results of the mechanical properties of these two compounds indicated that their microhardness and fracture toughness values were far superior to the other competing state-of-the-art thermoelectric materials.

  4. An in-situ phosphorus source for the synthesis of Cu3P and the subsequent conversion to Cu3PS4 nanoparticle clusters

    SciTech Connect

    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 (Cu3P) and copper thiophosphate (Cu3PS4). Herein, we report a one-pot, solution-based synthesis of Cu3P nanocrystals utilizing an in-situ phosphorus source: phosphorus pentasulfide (P2S5) in trioctylphosphine (TOP). By injecting this phosphorus source into a copper solution in oleylamine (OLA), uniform and size controlled Cu3P nanocrystals with a phosphorous-rich surface are synthesized. The subsequent reaction of the Cu3P nanocrystals with decomposing thiourea forms nanoscale Cu3PS4 particles having p-type conductivity and an effective optical band gap of 2.36 eV.

  5. Comparison of CsBr and KBr coated Cu photocathodes: Effects of laser irradiation and work function changes

    SciTech Connect

    He, Weidong; VilayurGanapathy, Subramanian; Joly, Alan G.; Droubay, Timothy C.; Chambers, Scott A.; Maldonado, Juan R.; Hess, Wayne P.

    2013-02-20

    Thin films (7 nm layers) of CsBr and KBr were deposited on Cu(100) to investigate photoemission properties of these potential photocathode materials. After thin film deposition and prolonged laser ultraviolet (UV) irradiation (266 nm picosecond laser) photoemission quantum efficiency increases by factors of 26 and 77 for KBr/Cu(100) and CsBr/Cu(100) photocathodes, respectively. Immediately following thin film deposition, a decrease in work function is observed, compared to bare Cu, in both cases. Quantum efficiency enhancements are attributed to the decrease in photocathode work function, due to the deposition of alkali halide thin films, and photo-induced processes, that introduce defect states into the alkali halide bandgap, induced by UV laser irradiation. It is possible that alkali metal formation occurs during UV irradiation and that this further contributes to photoemission enhancement. Our results suggest that KBr, a relatively stable alkali-halide, has potential for photocathode applications.

  6. Millimeter size single crystals of superconducting YBa[sub 2]Cu[sub 3]O[sub x

    DOEpatents

    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.

  7. Resonant elastic soft x-ray scattering in oxygen-ordered YBa2Cu3O6...

    Office of Scientific and Technical Information (OSTI)

    Resonant elastic soft x-ray scattering in oxygen-ordered YBa2Cu3O6+ Citation Details In-Document Search Title: Resonant elastic soft x-ray scattering in oxygen-ordered...

  8. Millimeter size single crystals of superconducting YBa.sub.2 Cu.sub.3 O.sub .

    DOEpatents

    Damento, Michael A.; Gschneidner, Jr., Karl A.

    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. High heat flux testing of HIP bonded DS-Cu/316SS first wall panel for fusion experimental reactors

    SciTech Connect

    Hatano, Toshihisa; Sato, Kazuyoshi; Dairaku, Masayuki

    1996-12-31

    A shielding blanket design in a fusion reactor such as ITER has been proposed to be a modulator structure integrated with the first wall. In terms of the fabrication, HIP (Hot Isostatic Pressing) method has been proposed for the joining of dispersion strengthened copper (DS-Cu) and type 316L stainless steel (SS316L) at FW. High heat flux tests of HIP bonded DS-Cu/SS316L first wall panel were performed at particle Beam Engineering Facility in JAERI to investigate its thermo-mechanical performance. After four campaigns of high heat flux testing, the FW panel was cut to observe the HIP bonded interface and heated surface of DS-Cu. Though melting of DS-Cu surface was observed, there were no cracks at the HIP bonded interface. 2 refs., 11 figs., 1 tab.

  10. A three-dimensional Macroporous Cu/SnO2 composite anode sheet prepared via a novel method

    SciTech Connect

    Xu, Wu; Canfield, Nathan L.; Wang, Deyu; Xiao, Jie; Nie, Zimin; Zhang, Jiguang

    2010-11-01

    Macroporous Cu/SnO2 composite anode sheets were prepared by a novel method which is based on slurry blending, tape casting, sintering, and reducing of metal oxides. Such composite Cu/SnO2 anode sheets have no conducting carbons and binders, and show improved discharge capacity and cycle life than the SnO2 electrode from conventional tape-casting method on Cu foil. This methodology produces limited wastes and is also adaptable to many other materials. It is easy for industrial scale production. With the optimization of particle size of the metal oxide, pore size, pore volume and other factors, this kind of macroporous Cu/SnO2 composite anode sheets could give significantly improved capacity and cycle life.

  11. Comment on 'The diatomic dication CuZn{sup 2+} in the gas phase' [J. Chem. Phys. 135, 034306 (2011)

    SciTech Connect

    Fiser, Jiri; Diez, Reinaldo Pis; Franzreb, Klaus; Alonso, Julio A.

    2013-02-21

    In this Comment, the density functional theory (DFT) calculations carried out by Diez et al. [J. Chem. Phys. 135, 034306 (2011)] are revised within the framework of the coupled-cluster single double triple method. These more sophisticated calculations allow us to show that the {sup 2}{Sigma}{sup +} electronic ground state of CuZn{sup 2+}, characterized as the metastable ground state by DFT calculations, is a repulsive state instead. The {sup 2}{Delta} and {sup 2}{Pi} metastable states of CuZn{sup 2+}, on the other hand, should be responsible for the formation mechanism of the dication through the near-resonant electron transfer CuZn{sup +}+ Ar{sup +}{yields} CuZn{sup 2+}+ Ar reaction.

  12. Nuclear matter effects on J/? production in asymmetric Cu+Au collisions at ?SNN=200 GeV

    DOE PAGES [OSTI]

    Adare, A.

    2014-12-18

    We report on J/? production from asymmetric Cu+Au heavy-ion collisions at ?sNN =200 GeV at the Relativistic Heavy Ion Collider at both forward (Cu-going direction) and backward (Au-going direction) rapidities. The nuclear modification of J/? yields in Cu+Au collisions in the Au-going direction is found to be comparable to that in Au+Au collisions when plotted as a function of the number of participating nucleons. In the Cu-going direction, J/? production shows a stronger suppression. This difference is comparable in magnitude and has the same sign as the difference expected from shadowing effects due to stronger low-x gluon suppression in themorelarger Au nucleus. The relative suppression is opposite to that expected from hot nuclear matter dissociation, since a higher energy density is expected in the Au-going direction.less

  13. Investigation of the oxidation states of Cu additive in colored borosilicate glasses by electron energy loss spectroscopy

    SciTech Connect

    Yang, Guang Cheng, Shaodong; Li, Chao; Ma, Chuansheng; Zhong, Jiasong; Xiang, Weidong; Wang, Zhao

    2014-12-14

    Three optically transparent colorful (red, green, and blue) glasses were synthesized by the sol-gel method. Nano-sized precipitates were found in scanning electron microscopy images. The precipitates were analyzed by transmission electron microscopy (TEM) and high resolution TEM. The measured lattice parameters of these precipitates were found to fit the metallic copper in red glass but deviate from single valenced Cu oxides in green and blue glasses. The chemistry of these nano-sized particles was confirmed by electron energy loss spectroscopy (EELS). By fitting the EELS spectra obtained from the precipitates with the linear combination of reference spectra from Cu reference compounds, the oxidation states of Cu in the precipitates have been derived. First principle calculations suggested that the Cu nano-particles, which are in the similar oxidation states as our measurement, would show green color in the visible light range.

  14. The equilibrium vortex melting transition in YBa{sub 2}Cu{sub 3}O{sub 7}

    SciTech Connect

    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.

  15. Size and alloying induced shift in core and valence bands of Pd-Ag and Pd-Cu nanoparticles

    SciTech Connect

    Sengar, Saurabh K.; Mehta, B. R.; Govind

    2014-03-28

    In this report, X-ray photoelectron spectroscopy studies have been carried out on Pd, Ag, Cu, Pd-Ag, and Pd-Cu nanoparticles having identical sizes corresponding to mobility equivalent diameters of 60, 40, and 20 nm. The nanoparticles were prepared by the gas phase synthesis method. The effect of size on valence and core levels in metal and alloy nanoparticles has been studied by comparing the values to those with the 60 nm nanoparticles. The effect of alloying has been investigated by comparing the valence and core level binding energies of Pd-Cu and Pd-Ag alloy nanoparticles with the corresponding values for Pd, Ag, and Cu nanoparticles of identical sizes. These effects have been explained in terms of size induced lattice contractions, alloying induced charge transfer, and hybridization effects. The observation of alloying and size induced binding energy shifts in bimetallic nanoparticles is important from the point of view of hydrogen reactivity.

  16. Thermal conductivity of consolidated Al/Cu/sub 2/O thermites

    SciTech Connect

    Miller, G.D.; Haws, L.D.

    1980-06-17

    Knowledge of the thermal conductivity, lambda, of Al/Cu/sub 2/O consolidated thermites is required in order to model the reaction and, in turn, understand and predict thermite burn rates, ignition temperatures, and sensitivities. Two methods, laser-flash and comparative, were evaluated. The comparative method was found to be the method of choice. Results of the lambda measurements are reported as functions of temperature, part density, and aluminum particle shape.

  17. Production of .sup.64 Cu and other radionuclides using a charged-particle accelerator

    DOEpatents

    Welch, Michael J.; McCarthy, Deborah W.; Shefer, Ruth E.; Klinkowstein, Robert E.

    2000-01-01

    Radionuclides are produced according to the present invention at commercially significant yields and at specific activities which are suitable for use in radiodiagnostic agents such as PET imaging agents and radiotherapeutic agents and/or compositions. In the method and system of the present invention, a solid target having an isotopically enriched target layer electroplated on an inert substrate is positioned in a specially designed target holder and irradiated with a charged-particle beam. The beam is preferably generated using an accelerator such as a biomedical cyclotron at energies ranging from about 5 MeV to about 25 MeV. The target is preferably directly irradiated, without an intervening attenuating foil, and with the charged particle beam impinging an area which substantially matches the target area. The irradiated target is remotely and automatically transferred from the target holder, preferably without transferring any target holder subassemblies, to a conveyance system which is preferably a pneumatic or hydraulic conveyance system, and then further transferred to an automated separation system. The system is effective for processing a single target or a plurality of targets. After separation, the unreacted target material can be recycled for preparation of other targets. In a preferred application of the invention, a biomedical cyclotron has been used to produce over 500 mCi of .sup.64 Cu having a specific activity of over 300 mCi/.mu.g Cu according to the reaction .sup.64 Ni(p,n).sup.64 Cu. These results indicate that accelerator-produced .sup.64 Cu is suitable for radiopharmaceutical diagnostic and therapeutic applications.

  18. Incorporation of trace elements in Portland cement clinker: Thresholds limits for Cu, Ni, Sn or Zn

    SciTech Connect

    Gineys, N.; Aouad, G.; Sorrentino, F.; Damidot, D.

    2011-11-15

    This paper aims at defining precisely, the threshold limits for several trace elements (Cu, Ni, Sn or Zn) which correspond to the maximum amount that could be incorporated into a standard clinker whilst reaching the limit of solid solution of its four major phases (C{sub 3}S, C{sub 2}S, C{sub 3}A and C{sub 4}AF). These threshold limits were investigated through laboratory synthesised clinkers that were mainly studied by X-ray Diffraction and Scanning Electron Microscopy. The reference clinker was close to a typical Portland clinker (65% C{sub 3}S, 18% C{sub 2}S, 8% C{sub 3}A and 8% C{sub 4}AF). The threshold limits for Cu, Ni, Zn and Sn are quite high with respect to the current contents in clinker and were respectively equal to 0.35, 0.5, 0.7 and 1 wt.%. It appeared that beyond the defined threshold limits, trace elements had different behaviours. Ni was associated with Mg as a magnesium nickel oxide (MgNiO{sub 2}) and Sn reacted with lime to form a calcium stannate (Ca{sub 2}SnO{sub 4}). Cu changed the crystallisation process and affected therefore the formation of C{sub 3}S. Indeed a high content of Cu in clinker led to the decomposition of C{sub 3}S into C{sub 2}S and of free lime. Zn, in turn, affected the formation of C{sub 3}A. Ca{sub 6}Zn{sub 3}Al{sub 4}O{sub 15} was formed whilst a tremendous reduction of C{sub 3}A content was identified. The reactivity of cements made with the clinkers at the threshold limits was followed by calorimetry and compressive strength measurements on cement paste. The results revealed that the doped cements were at least as reactive as the reference cement.

  19. Texture analysis of bulk YBa sub 2 Cu sub 3 O sub x by neutron diffraction

    SciTech Connect

    Kallend, J.S. ); Biondo, A.C.; Schultz, A.J.; Goretta, K.C. )

    1990-09-01

    Neutron diffraction has been used to generate Orientation Distribution Functions for two sinter-forged YBa{sub 2}Cu{sub 3}O{sub x} specimens. Sinter forging imparted a strong texture, with c axes of crystals preferentially aligned parallel to the forging direction. The distribution of a and b axes was not uniform, which may have implications to critical current density. 14 refs., 6 figs.

  20. Microsoft Word - CU-ShEEP Information Exchange Webinar_Venayagamoorthy.docx

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    DE-OE0000660 Page 1 of 3 Project Title: CU-ShEEP Clemson University's Synchrophasor Engineering Education Program Principal Investigator: G. Kumar Venayagamoorthy Clemson University 303D Riggs Hall, Clemson, SC 29634 gvenaya@clemson.edu Tel. No. 864-6565936 A. PROJECT DESCRIPTION The objective of this project is to establish collaboration with a local utility - Duke Energy, in establishing a Situational Intelligence (SI) Laboratory that will be driven from a Real-Time Grid Simulation Laboratory

  1. A high temperature diffraction-resistance study of chalcopyrite, CuFeS{sub 2}

    SciTech Connect

    Engin, T.E.; Powell, A.V.; Hull, S.

    2011-08-15

    The electrical, magnetic and structural properties of synthetic chalcopyrite, CuFeS{sub 2}, have been studied up to 873 K using DC resistance measurements performed in-situ during neutron powder diffraction experiments. Under ambient conditions the material adopts the accepted structural model for CuFeS{sub 2} in the space group I4-bar 2d, with the magnetic moment of the Fe{sup 3+} cations aligned along [001]. The electrical resistivity is around 0.3 {Omega} cm under ambient conditions, consistent with semiconductor character, and decreases slightly with increase in temperature until a more abrupt fall occurs in the region 750-800 K. This abrupt change in resistivity is accompanied by a structural transition to a cubic zinc blende structured phase (space group F4-bar 3m) in which Cu{sup +} and Fe{sup 3+} cations are disordered over the same tetrahedral crystallographic sites and by a simultaneous loss of long-range magnetic order. The implications of these results are discussed in the context of previous studies of the chalcopyrite system. - Graphical abstract: Structural, magnetic and electrical properties of CuFeS{sub 2} to 873 K have been investigated using DC resistance measurements, performed in-situ during the collection of powder neutron diffraction data. Highlights: > Structural, magnetic and electronic properties are probed simultaneously. > A fall in resistivity at high temperatures is associated with cation disorder. > The order-disorder transition is accompanied by the loss of magnetic order. > The structural and magnetic phase transition is preceded by a 2-phase region. > Sulphur loss at high temperatures causes the phase transitions to be irreversible.

  2. Barrier to Trap Filling CuIn1-xGaxSe2: Preprint

    SciTech Connect

    Young, D. L.; Ramanathan, K.; Contreras, M.; Abushama, J.; Crandall, R. S.

    2003-04-01

    Voltage pulses of variable length were applied to CuIn1-xGaxSe2/CdS (0< x< 1) junction solar cells. The resulting transient capacitance emission signal was recorded for several minutes. The amplitude of the capacitance emission signal increased linearly with the log of pulse time. These data do not follow the standard model for trap capture and emission of carriers. Instead they follow a simple electrostatic model based on electrostatic charging of traps.

  3. CU-CTVI-1-B Wholesale Power Rate Schedule | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    CTVI-1-B Wholesale Power Rate Schedule CU-CTVI-1-B Wholesale Power Rate Schedule Area: Former customers of TVA System: Cumberland This rate schedule shall be available to customers (hereinafter called the Customer) who are or were formerly in the Tennessee Valley Authority (hereinafter called TVA) service area. This rate schedule shall be applicable to electric capacity and energy generated at the Dale Hollow, Center Hill, Wolf Creek, Old Hickory, Cheatham, Barkley, J. Percy Priest, and Cordell

  4. Size Dependence of S-bonding on (111) Facets of Cu Nanoclusters

    DOE PAGES [OSTI]

    Boschen, Jeffery S.; Lee, Jiyoung; Windus, Theresa L.; Evans, James W.; Liu, Da-Jiang

    2016-04-21

    We demonstrate a strong damped oscillatory size dependence of the adsorption energy for sulfur on the (111) facets of tetrahedral Cu nanoclusters up to sizes of ~300 atoms. This behavior reflects quantum size effects. Consistent results are obtained from density functional theory analyses utilizing either atomic orbital or plane-wave bases and using the same Perdew–Burke–Ernzerhof functional. Behavior is interpreted via molecular orbitals (MO), density of states (DOS), and crystal orbital Hamilton population (COHP) analyses.

  5. Intermetallic M-Sn5 (M=Fe, Cu, Co, Ni) Compounds - Energy Innovation Portal

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Vehicles and Fuels Vehicles and Fuels Advanced Materials Advanced Materials Find More Like This Return to Search Intermetallic M-Sn5 (M=Fe, Cu, Co, Ni) Compounds Brookhaven National Laboratory Contact BNL About This Technology Technology Marketing Summary Among electrode materials for lithium ion batteries, tin offers a high theoretical capacity about 2.5 times that of graphite by weight. Unfortunately, when lithium alloys with tin the matrix undergoes a very large volume change. This change in

  6. Novel bimetallic thiocyanate-bridged Cu(II)-Hg(II) compounds-synthesis, X-Ray studies and magnetic properties

    SciTech Connect

    Machura, B.; Switlicka, A.; Zwolinski, P.; Mrozinski, J.; Kalinska, B.; Kruszynski, R.

    2013-01-15

    Seven novel heterobimetallic Cu/Hg polymers based on thiocyanate bridges have been synthesised and characterised by means of IR, EPR, magnetic measurements and single crystal X-Ray. Three of them, [Cu(pzH){sub 4}Hg(SCN){sub 4}]{sub n} (1) [Cu(indH){sub 4}Hg(SCN){sub 4}]{sub n} (2) and [Cu(ampy){sub 2}Hg(SCN){sub 4}]{sub n} (3), have one-dimensional coordination structure. Two compounds [Cu(pzH){sub 2}Hg(SCN){sub 4}]{sub n} (4) and [Cu(abzimH)Hg(SCN){sub 4}]{sub n} (5) form two-dimensional nets, whereas the complexes [Cu(pyCN){sub 2}Hg(SCN){sub 4}]{sub n} (6) and [Cu(pyCH(OH)(OMe)){sub 2}Hg(SCN){sub 4}]{sub n} (7) are three-dimensional coordination polymers. The chains of 1 are connected by the intermolecular N-H Bullet Bullet Bullet N hydrogen bonds to the three dimensional net. In 2 the N-H Bullet Bullet Bullet S hydrogen bonds link the polymeric chains to the two dimensional layer extending along crystallographic (0 0 1) plane. The polymeric chains of compound 3 are joined by the intermolecular N-H Bullet Bullet Bullet N and N-H Bullet Bullet Bullet S hydrogen bonds to the three dimensional net. The polymeric layers of 4 are connected by the intermolecular N-H Bullet Bullet Bullet N hydrogen bonds to the three dimensional net. - Graphical abstract: Novel bimetallic thiocyanate-bridged Cu(II)-Hg(II) compound-synthesis,X-Ray studies and magnetic properties. Highlights: Black-Right-Pointing-Pointer Novel heterobimetallic Cu/Hg coordination polymers were synthesised. Black-Right-Pointing-Pointer The multidimensional structures have been proved by single X-ray analysIs. Black-Right-Pointing-Pointer A variation in the crystalline architectures was observed depending on auxiliary ligands. Black-Right-Pointing-Pointer Magnetic measurements indicate weak exchange interaction between Cu(II) in the crystal lattices below 10 K.

  7. Current Understanding of Cu-Exchanged Chabazite Molecular Sieves for Use as Commercial Diesel Engine DeNOx Catalysts

    SciTech Connect

    Gao, Feng; Kwak, Ja Hun; Szanyi, Janos; Peden, Charles HF

    2013-11-03

    Selective catalytic reduction (SCR) of NOx with ammonia using metal-exchanged molecular sieves with a chabazite (CHA) structure has recently been commercialized on diesel vehicles. One of the commercialized catalysts, i.e., Cu-SSZ-13, has received much attention for both practical and fundamental studies. For the latter, the particularly well-defined structure of this zeolite is allowing long-standing issues of the catalytically active site for SCR in metal-exchanged zeolites to be addressed. In this review, recent progress is summarized with a focus on two areas. First, the technical significance of Cu-SSZ-13 as compared to other Cu-ion exchanged zeolites (e.g., Cu-ZSM-5 and Cu-beta) is highlighted. Specifically, the much enhanced hydrothermal stability for Cu-SSZ-13 compared to other zeolite catalysts is addressed via performance measurements and catalyst characterization using several techniques. The enhanced stability of Cu-SSZ-13 is rationalized in terms of the unique small pore structure of this zeolite catalyst. Second, the fundamentals of the catalytically active center; i.e., the chemical nature and locations within the SSZ-13 framework are presented with an emphasis on understanding structure-function relationships. For the SCR reaction, traditional kinetic studies are complicated by intra-particle diffusion limitations. However, a major side reaction, nonselective ammonia oxidation by oxygen, does not suffer from mass-transfer limitations at relatively low temperatures due to significantly lower reaction rates. This allows structure-function relationships that are rather well understood in terms of Cu ion locations and redox properties. Finally, some aspects of the SCR reaction mechanism are addressed on the basis of in-situ spectroscopic studies.

  8. Pressure-driven orbital reorientations and coordination-sphere reconstructions in [CuF2(H2O)2(pyz)

    SciTech Connect

    Prescimone, A.; Morien, C.; Allan, D.; Schlueter, J.; Tozer, S.; Manson, J. L.; Parsons, S.; Brechin, E. K.; Hill, S.

    2012-07-23

    Successive reorientations of the Jahn-Teller axes associated with the Cu{sup II} ions accompany a series of pronounced structural transitions in the title compound, as is shown by X-ray crystallography and high-frequency EPR measurements. The second transition forces a dimerization involving two thirds of the Cu{sup II} sites due to ejection of one of the water molecules from the coordination sphere

  9. Antiferromagnetism in EuCu2As2 and EuCu1.82Sb2 single crystals

    SciTech Connect

    Anand, V. K.; Johnston, D. C.

    2015-05-07

    Single crystals of EuCu2As2 and EuCu2Sb2 were grown from CuAs and CuSb self-flux, respectively. The crystallographic, magnetic, thermal, and electronic transport properties of the single crystals were investigated by room-temperature x-ray diffraction (XRD), magnetic susceptibility χ versus temperature T, isothermal magnetization M versus magnetic field H, specific heat Cp(T), and electrical resistivity ρ(T) measurements. EuCu2As2 crystallizes in the body-centered tetragonal ThCr2Si2-type structure (space group I4/mmm), whereas EuCu2Sb2 crystallizes in the related primitive tetragonal CaBe2Ge2-type structure (space group P4/nmm). The energy-dispersive x-ray spectroscopy and XRD data for the EuCu2Sb2 crystals showed the presence of vacancies on the Cu sites, yielding the actual composition EuCu1.82Sb2. The ρ(T) and Cp(T) data reveal metallic character for both EuCu2As2 and EuCu1.82Sb2. Antiferromagnetic (AFM) ordering is indicated from the χ(T),Cp(T), and ρ(T) data for both EuCu2As2 (TN = 17.5 K) and EuCu1.82Sb2 (TN = 5.1 K). In EuCu1.82Sb2, the ordered-state χ(T) and M(H) data suggest either a collinear A-type AFM ordering of Eu+2 spins S = 7/2 or a planar noncollinear AFM structure, with the ordered moments oriented in the tetragonal ab plane in either case. This ordered-moment orientation for the A-type AFM is consistent with calculations with magnetic dipole interactions. As a result, the anisotropic χ(T) and isothermal M(H) data for EuCu2As2, also containing Eu+2 spins S = 7/2, strongly deviate from the predictions of molecular field theory for collinear AFM ordering and the

  10. Electronic structure, irreversibility line and magnetoresistance of Cu0.3Bi2Se3 superconductor

    DOE PAGES [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; et al

    2015-06-01

    CuxBi2Se3 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 CuxBi2Se3 superconductor, and a detailed magneto-resistance measurement in both normal and superconducting states. We find that the topological surface state of the pristine Bi2Se3 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 formore » the Cu0.3Bi2Se3 superconductor with a middle point Tc 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 Cu0.3Bi2Se3 superconductors up to room temperature. As a result, these observations provide useful information for further study of this possible candidate for topological superconductors.« less

  11. High critical currents in heavily doped (Gd,Y)Ba2Cu3Ox superconductor tapes

    DOE PAGES [OSTI]

    Selvamanickam, V.; Gharahcheshmeh, M. Heydari; Xu, A.; Galstyan, E.; Delgado, L.; Cantoni, C.

    2015-01-20

    REBa2Cu3Ox superconductor tapes with moderate levels of dopants have been optimized for high critical current density in low magnetic fields at 77 K, but they do not exhibit exemplary performance in conditions of interest for practical applications, i.e., temperatures less than 50 K and fields of 2–30 T. Heavy doping of REBCO tapes has been avoided by researchers thus far due to deterioration in properties. Here, we report achievement of critical current densities (Jc) above 20 MA/cm2 at 30 K, 3 T in heavily doped (25 mol. % Zr-added) (Gd,Y)Ba2Cu3Ox superconductor tapes, which is more than three times higher thanmore » the Jc typically obtained in moderately doped tapes. Pinning force levels above 1000 GN/m3 have also been attained at 20 K. A composition map of lift factor in Jc (ratio of Jc at 30 K, 3 T to the Jc at 77 K, 0 T) has been developed which reveals the optimum film composition to obtain lift factors above six, which is thrice the typical value. A highly c-axis aligned BaZrO3 (BZO) nanocolumn defect density of nearly 7 × 1011 cm–2 as well as 2–3nm sized particles rich in Cu and Zr have been found in the high Jc films.« less

  12. Microstructure control of Al-Cu films for improved electromigration resistance

    DOEpatents

    Frear, D.R.; Michael, J.R.; Romig, A.D. Jr.

    1994-04-05

    A process for the forming of Al-Cu conductive thin films with reduced electromigration failures is useful, for example, in the metallization of integrated circuits. An improved formation process includes the heat treatment or annealing of the thin film conductor at a temperature within the range of from 200 C to 300 C for a time period between 10 minutes and 24 hours under a reducing atmosphere such as 15% H[sub 2] in N[sub 2] by volume. Al-Cu thin films annealed in the single phase region of a phase diagram, to temperatures between 200 C and 300 C have [theta]-phase Al[sub 2] Cu precipitates at the grain boundaries continuously become enriched in copper, due, it is theorized, to the formation of a thin coating of [theta]-phase precipitate at the grain boundary. Electromigration behavior of the aluminum is, thus, improved because the [theta]-phase precipitates with copper hinder aluminum diffusion along the grain boundaries. Electromigration, then, occurs mainly within the aluminum grains, a much slower process. 5 figures.

  13. 110K Bi-Sr-Ca-Cu-O superconductor oxide and method for making same

    DOEpatents

    Veal, Boyd W.; Downey, John W.; Lam, Daniel J.; Paulikas, Arvydas P.

    1992-01-01

    A superconductor consisting of a sufficiently pure phase of the oxides of Bi, Sr, Ca, and Cu to exhibit a resistive zero near 110K resulting from the process of forming a mixture of Bi.sub.2 O.sub.3, SrCO.sub.3, CaCO.sub.3 and CuO into aparticulate compact wherein the atom ratios are Bi.sub.2, Sr.sub.1.2-2.2, Ca.sub.1.8-2.4, Cu.sub.3. Thereafter, heating the particulate compact rapidly in the presence of oxygen to an elevated temperature near the melting point of the oxides to form a sintered compact, and then maintaining the sintered compact at the elevated temperature for a prolonged period of time. The sintered compact is cooled and reground. Thereafter, the reground particulate material is compacted and heated in the presence of oxygen to an elevated temperature near the melting point of the oxide and maintained at the elevated temperature for a time sufficient to provide a sufficiently pure phase to exhibit a resistive zero near 110K.

  14. 110K Bi-Sr-Ca-Cu-O superconductor oxide and method for making same

    DOEpatents

    Veal, B.W.; Downey, J.W.; Lam, D.J.; Paulikas, A.P.

    1992-12-22

    A superconductor is disclosed consisting of a sufficiently pure phase of the oxides of Bi, Sr, Ca, and Cu to exhibit a resistive zero near 110K resulting from the process of forming a mixture of Bi[sub 2]O[sub 3], SrCO[sub 3], CaCO[sub 3] and CuO into a particulate compact wherein the atom ratios are Bi[sub 2], Sr[sub 1.2-2.2], Ca[sub 1.8-2.4], Cu[sub 3]. Thereafter, heating the particulate compact rapidly in the presence of oxygen to an elevated temperature near the melting point of the oxides to form a sintered compact, and then maintaining the sintered compact at the elevated temperature for a prolonged period of time. The sintered compact is cooled and reground. Thereafter, the reground particulate material is compacted and heated in the presence of oxygen to an elevated temperature near the melting point of the oxide and maintained at the elevated temperature for a time sufficient to provide a sufficiently pure phase to exhibit a resistive zero near 110K. 7 figs.

  15. Cooperative Island Growth of Large Area Single-Crystal Graphene by Chemical Vapor Deposition on Cu

    SciTech Connect

    Regmi, Murari [Oak Ridge National Laboratory (ORNL); Rouleau, Christopher [Oak Ridge National Laboratory (ORNL); Puretzky, Alexander A [ORNL; Ivanov, Ilia N [ORNL; Geohegan, David B [ORNL; Chen, Jihua [ORNL; Eastman, Jeffrey [Argonne National Laboratory (ANL); Eres, Gyula [ORNL

    2014-01-01

    We describe a two-step approach for suppressing nucleation of graphene on Cu using chemical vapor deposition. In the first step, as received Cu foils are oxidized in air at temperatures up to 500 C to remove surface impurities and to induce the regrowth of Cu grains during subsequent annealing in H2 flow at 1040 C prior to graphene growth. In the second step, transient reactant cooling is performed by using a brief Ar pulse at the onset of growth to induce collisional deactivation of the carbon growth species. The combination of these two steps results in a three orders of magnitude reduction in the graphene nucleation density, enabling the growth of millimeter-size single crystal graphene grains. A kinetic model shows that suppressing nucleation promotes a cooperative island growth mode that favors the formation of large area single crystal graphene, and it is accompanied by a roughly 3 orders of magnitude increase in the reactive sticking probability of methane compared to that in random nucleation growth.

  16. Microstructure control of Al-Cu films for improved electromigration resistance

    DOEpatents

    Frear, Darrel R.; Michael, Joseph R.; Romig, Jr., Alton D.

    1994-01-01

    A process for the forming of Al-Cu conductive thin films with reduced electromigration failures is useful, for example, in the metallization of integrated circuits. An improved formation process includes the heat treatment or annealing of the thin film conductor at a temperature within the range of from 200.degree. C. to 300.degree. C. for a time period between 10 minutes and 24 hours under a reducing atmosphere such as 15% H.sub.2 in N.sub.2 by volume. Al-Cu thin films annealed in the single phase region of a phase diagram, to temperatures between 200.degree. C. and 300.degree. C. have .theta.-phase Al.sub.2 Cu precipitates at the grain boundaries continuously become enriched in copper, due, it is theorized, to the formation of a thin coating of .theta.-phase precipitate at the grain boundary. Electromigration behavior of the aluminum is, thus, improved because the .theta.-phase precipitates with copper hinder aluminum diffusion along the grain boundaries. Electromigration, then, occurs mainly within the aluminum grains, a much slower process.

  17. Colloidal synthesis and characterization of carbon-supported Pd-Cu nanoparticle oxygen reduction electrocatalysts.

    SciTech Connect

    Kariuki, N. N.; Wang, X.; Mawdsley, J. R.; Ferrandon, M. S.; Niyogi, S. G.; Vaughey, J. T.; Myers, D. J.; Chemical Sciences and Engineering Division

    2010-07-27

    The ability to control the size and composition of metal or alloys nanoparticles is important in preparing catalysts. This paper reports a colloidal synthesis methodology for the preparation of monodisperse palladium-copper (Pd-Cu) alloy nanoparticles with an average diameter of 3 nm for the as-prepared particles and 5-10 nm upon removal of the capping agents. Our approach involves the use of metal precursors, capping agents, and reducing agents in controlled ratios for nanoparticle formation in a single organic phase, followed by deposition of the capped nanoparticles on high surface area carbon and removal of the capping agents via heat treatment in either oxidizing or reducing atmosphere. The results of characterizations using transmission electron microscopy-energy dispersive X-ray analysis (TEM-EDX), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), temperature programmed oxidation and reduction combined with mass spectrometry (TPO/TPR-MS), powder X-ray diffraction (XRD), and cyclic voltammetry (CV) are discussed. The resulting high-surface-area-carbon-supported Pd-Cu catalysts (PdCu/C) showed high activity for the oxygen reduction reaction (ORR) in acidic electrolyte. Our study revealed composition and heat-treatment dependent ORR activity.

  18. Surface and grain boundary scattering in nanometric Cu thin films: A quantitative analysis including twin boundaries

    SciTech Connect

    Barmak, Katayun [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 and Department of Materials Science and Engineering and Materials Research Science and Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Darbal, Amith [Department of Materials Science and Engineering and Materials Research Science and Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Ganesh, Kameswaran J.; Ferreira, Paulo J. [Materials Science and Engineering, The University of Texas at Austin, 1 University Station, Austin, Texas 78712 (United States); Rickman, Jeffrey M. [Department of Materials Science and Engineering and Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Sun, Tik; Yao, Bo; Warren, Andrew P.; Coffey, Kevin R., E-mail: kb2612@columbia.edu [Department of Materials Science and Engineering, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816 (United States)

    2014-11-01

    The relative contributions of various defects to the measured resistivity in nanocrystalline Cu were investigated, including a quantitative account of twin-boundary scattering. It has been difficult to quantitatively assess the impact twin boundary scattering has on the classical size effect of electrical resistivity, due to limitations in characterizing twin boundaries in nanocrystalline Cu. In this study, crystal orientation maps of nanocrystalline Cu films were obtained via precession-assisted electron diffraction in the transmission electron microscope. These orientation images were used to characterize grain boundaries and to measure the average grain size of a microstructure, with and without considering twin boundaries. The results of these studies indicate that the contribution from grain-boundary scattering is the dominant factor (as compared to surface scattering) leading to enhanced resistivity. The resistivity data can be well-described by the combined FuchsSondheimer surface scattering model and MayadasShatzkes grain-boundary scattering model using Matthiessen's rule with a surface specularity coefficient of p?=?0.48 and a grain-boundary reflection coefficient of R?=?0.26.

  19. Comparative Density Functional Study of Methanol Decomposition on Cu4 and Co4 Clusters

    SciTech Connect

    Mehmood, Faisal; Greeley, Jeffrey P.; Zapol, Peter; Curtiss, Larry A.

    2010-11-18

    A density functional theory study of the decomposition of methanol on Cu4 and Co4 clusters is presented. The reaction intermediates and activation barriers have been determined for reaction steps to form H2 and CO. For both clusters, methanol decomposition initiated by C-H and O-H bond breaking was investigated. In the case of a Cu4 cluster, methanol dehydrogenation through hydroxymethyl (CH2OH), hydroxymethylene (CHOH), formyl (CHO), and carbon monoxide (CO) is found to be slightly more favorable. For a Co4 cluster, the dehydrogenation pathway through methoxy (CH3O) and formaldehyde (CH2O) is slightly more favorable. Each of these pathways results in formation of CO and H2. The Co cluster pathway is very favorable thermodynamically and kinetically for dehydrogenation. However, since CO binds strongly, it is likely to poison methanol decomposition to H2 and CO at low temperatures. In contrast, for the Cu cluster, CO poisoning is not likely to be a problem since it does not bind strongly, but the dehydrogenation steps are not energetically favorable. Pathways involving C-O bond cleavage are even less energetically favorable. The results are compared to our previous study of methanol decomposition on Pd4 and Pd8 clusters. Finally, all reaction energy changes and transition state energies, including those for the Pd clusters, are related in a linear, Broensted-Evans-Polanyi plot.

  20. Auto-combustion synthesis and characterization of Mg doped CuAlO{sub 2} nanoparticles

    SciTech Connect

    Agrawal, Shraddha Parveen, Azra; Naqvi, A. H.

    2015-06-24

    The synthesis of pure and Mg doped Copper aluminumoxide CuAlO{sub 2}nanoparticles, a promising p-type TCO (transparent conducting oxide) have been done bysol gel auto combustion method using NaOH as a fuel, calcinated at 600°C. The structural properties were examined by XRD and SEM techniques. The optical absorption spectra of CuAlO{sub 2} sample recorded by UV-VIS spectrophotometer in the range of 200 to 800 nm have been presented. The crystallite size was determined by powder X-ray diffraction technique. The electrical behavior of pure and Mg doped CuAlO{sub 2} has been studied over a wide range of frequencies by using complex impedance spectroscopy.The variation of a.c. conductivity has been studied as function of frequency and temperature. The data taken together conclude that doping causes decreases in the ac conductivity of the nanoparticles as compared with the pure nanoparticles. Mg doping affects the optical properties and band gap.

  1. Molecular dynamical simulation of the behavior of early precipitated stage in aging process in dilute Cu-Cr alloy

    SciTech Connect

    Feng, J.; Liu, L.; Chen, J.; Du, Y.; Zhou, R.; Xiao, B.

    2010-06-15

    The aging behaviors of Cu-Cr alloys in the early stage at different temperatures are investigated by molecular dynamics simulations. First principles potentials are used for the interactions between Cu and Cr atoms. The initial behavior of precipitation is characterized by transmission electron microscope and electron energy disperse spectroscopy. The results showed that Cu-Cr supersaturated solid solution is thermodynamically unstable. The mean-square displacements of the atoms are used to describe the diffusivity. At room temperature, the atoms only show harmonic vibrations near the equilibrium positions. The mutual diffusion at 873 K is different from the unidirectional diffusion in low temperatures. The calculation shows that aging process is accelerated with increasing temperature, which is not only due to the lower diffusion activation energy of Cr at higher temperature, but also because Cu atoms are also participated in the aging process. When ''aging'' at 1073 K, the precipitation of Cr element is dissolved again into Cu matrix, which is an ''over-aging'' state of Cu-Cr alloy at high temperature.

  2. Enhancement of spin-Seebeck effect by inserting ultra-thin Fe{sub 70}Cu{sub 30} interlayer

    SciTech Connect

    Kikuchi, D.; Ishida, M.; Murakami, T.; Uchida, K.; Qiu, Z.; Saitoh, E.

    2015-02-23

    We report the longitudinal spin-Seebeck effects (LSSEs) for Pt/Fe{sub 70}Cu{sub 30}/BiY{sub 2}Fe{sub 5}O{sub 12} (BiYIG) and Pt/BiYIG devices. The LSSE voltage was found to be enhanced by inserting an ultra-thin Fe{sub 70}Cu{sub 30} interlayer. This enhancement decays sharply with increasing the Fe{sub 70}Cu{sub 30} thickness, suggesting that it is not due to bulk phenomena, such as a superposition of conventional thermoelectric effects, but due to interface effects related to the Fe{sub 70}Cu{sub 30} interlayer. Combined with control experiments using Pt/Fe{sub 70}Cu{sub 30} devices, we conclude that the enhancement of the LSSE voltage in the Pt/Fe{sub 70}Cu{sub 30}/BiYIG devices is attributed to the improvement of the spin-mixing conductance at the Pt/BiYIG interfaces.

  3. Catalytic conversion of syngas to mixed alcohols over Zn-Mn promoted Cu-Fe based catalyst

    SciTech Connect

    Lu, Yongwu; Yu, Fei; Hu, Jin; Liu, Jian

    2012-04-12

    Zn-Mn promoted Cu-Fe based catalyst was synthesized by the co-precipitation method. Mixed alcohols synthesis from syngas was studied in a half-inch tubular reactor system after the catalyst was reduced. Zn-Mn promoted Cu-Fe based catalyst was characterized by SEM-EDS, TEM, XRD, and XPS. The liquid phase products (alcohol phase and hydrocarbon phase) were analyzed by GC-MS and the gas phase products were analyzed by GC. The results showed that Zn-Mn promoted Cu-Fe based catalyst had high catalytic activity and high alcohol selectivity. The maximal CO conversion rate was 72%, and the yield of alcohol and hydrocarbons were also very high. Cu (111) was the active site for mixed alcohols synthesis, Fe2C (101) was the active site for olefin and paraffin synthesis. The reaction mechanism of mixed alcohols synthesis from syngas over Zn-Mn promoted Cu-Fe based catalyst was proposed. Here, Zn-Mn promoted Cu-Fe based catalyst can be regarded as a potential candidate for catalytic conversion of biomass-derived syngas to mixed alcohols.

  4. High-performing visible-blind photodetectors based on SnO{sub 2}/CuO nanoheterojunctions

    SciTech Connect

    Xie, Ting; Hasan, Md Rezaul; Qiu, Botong; Arinze, Ebuka S.; Thon, Susanna M.; Nguyen, Nhan V.; Motayed, Abhishek; Debnath, Ratan

    2015-12-14

    We report on the significant performance enhancement of SnO{sub 2} thin film ultraviolet (UV) photodetectors (PDs) through incorporation of CuO/SnO{sub 2} p-n nanoscale heterojunctions. The nanoheterojunctions are self-assembled by sputtering Cu clusters that oxidize in ambient to form CuO. We attribute the performance improvements to enhanced UV absorption, demonstrated both experimentally and using optical simulations, and electron transfer facilitated by the nanoheterojunctions. The peak responsivity of the PDs at a bias of 0.2 V improved from 1.9 A/W in a SnO{sub 2}-only device to 10.3 A/W after CuO deposition. The wavelength-dependent photocurrent-to-dark current ratio was estimated to be ∼592 for the CuO/SnO{sub 2} PD at 290 nm. The morphology, distribution of nanoparticles, and optical properties of the CuO/SnO{sub 2} heterostructured thin films are also investigated.

  5. Interfacial interaction of in situ Cu growth on tetrasulfide self-assembled monolayer on plasma treated parylene surface

    SciTech Connect

    Pimanpang, S.; Wang, Pei-I; Juneja, Jasbir S.; Wang, G.-C.; Lu, T.-M.

    2006-09-15

    The interfacial reactions of in situ grown Cu and functionalized parylene surfaces were examined using the x-ray photoelectron spectroscopy (XPS). It is observed that bis[3(triethoxysilane)propyl]tetrasulfide (tetrasulfide) forms a self-assembled monolayer (SAM) only on a parylene surface treated with either He plasma or N{sub 2} plasma, but not on the as-deposited parylene surface due to its lack of functional groups. The functional groups on the plasma treated parylene surface facilitate the formation of tetrasulfide SAM that subsequently improves the reactivity of parylene to Cu. The XPS spectra show a strong shift ({approx}1.1 eV) of the S 2p peaks from a higher binding energy to a lower binding energy, which suggests the existence of an interaction between sulfide and Cu. In addition, the result of a higher XPS intensity ratio of Cu 2p{sub 3/2}/C 1s for Cu growth on tetrasulfide SAM/plasma treated parylene surface than that of an as-deposited parylene surface indicates that the formation of tetrasulfide moiety (-SSSS-) on functionalized parylene surface leads to the increase of Cu growth rate.

  6. Thermoelectric and Structural Characterization of Ba2Ho(Cu3-xCox)O6+y

    SciTech Connect

    Wong-Ng, W.; Li, Q.; Yang, Z.; Hu, Y.F.; Huang, Q.; Lowhorn, N.; Otani, M.; Kaduk, J.A.

    2009-03-18

    The search for thermoelectric materials for power generation and for solid-state cooling has led to increased interest of layered cobalt-containing oxides because of their thermal stability at high temperature and their desirable thermoelectric properties. This paper examines the effect of substitution of Co in the layered pervoskite Ba{sub 2}Ho(Cu{sub 3-x}Co{sub x})O{sub 6+y} (x = 0.3, 0.4, 0.5, 0.6, and 1.0). Structural analysis using the neutron Rietveld refinement technique reveals that when x {le} 0.4, Co substitutes mainly for Cu in the 'chain sites' of the Ba{sub 2}Ho(Cu{sub 3-x}Co{sub x})O{sub 6+y} structure. As x > 0.4, Co also enters in the Cu-O 'plane sites' as well. The thermoelectric properties of polycrystalline Ba{sub 2}Ho(Cu{sub 3-x}Co{sub x})O{sub 6+y} samples were studied in the temperature range of 10-390 K. In general, as the cobalt content x increases, the resistivity and Seebeck coefficient of these samples increase while the thermal conductivity decreases. Among the five Ba{sub 2}Ho(Cu{sub 3-x}Co{sub x})O{sub 6+y} compositions, the x = 0.4 member gives the highest figure of merit ZT of {approx} 0.02 at approximately 270 K.

  7. Atomic-scale imaging and electronic structure determination of catalytic sites on Pd/Cu near surface alloys

    SciTech Connect

    Tierney, H.L.; Baber, A.E.; Sykes, E.C.H.

    2009-04-15

    Water-gas shift chemistry provides a useful method for producing hydrogen from coal; however, fuel cell applications demand that this hydrogen be free of impurities. Due to their unique properties, Pd/Cu alloys represent an import class of materials used for H purification membranes and also serve as the active metals in many heterogeneous catalysts. Little is known about how Pd and Cu interact electronically in these mixed systems and there is debate in the literature over the direction of charge transfer between the two species. This study used the differential conductance (dI/dV) spectroscopy capabilities of a low-temperature scanning tunneling microscope (STM) to investigate the atomic-scale electronic structure of Pd/Cu surface alloys. dI/dV spectroscopy gives a direct measure of the local density of states of surface sites with subnanometer precision. Results from this work demonstrate that individual, isolated Pd atoms in a Cu lattice are almost electronically identical to their host atoms. Over an energy range that spans 1 eV on either side of the Fermi level, the only significant electronic difference between isolated Pd and their host Cu atoms is that Pd atoms have a very slightly depleted electron density in the region of the Cu surface state maximum.

  8. Bacteriostatic and anti-collagenolytic dental materials through the incorporation of polyacrylic acid modified CuI nanoparticles

    DOEpatents

    Renne, Walter George; Mennito, Anthony Samuel; Schmidt, Michael Gerard; Vuthiganon, Jompobe; Chumanov, George

    2015-05-19

    Provided are antibacterial and antimicrobial surface coatings and dental materials by utilizing the antimicrobial properties of copper chalcogenide and/or copper halide (CuQ, where Q=chalcogens including oxygen, or halogens, or nothing). An antimicrobial barrier is created by incorporation of CuQ nanoparticles of an appropriate size and at a concentration necessary and sufficient to create a unique bioelectrical environment. The unique bioelectrical environment results in biocidal effectiveness through a multi-factorial mechanism comprising a combination of the intrinsic quantum flux of copper (Cu.sup.0, Cu.sup.1+, Cu.sup.2+) ions and the high surface-to-volume electron sink facilitated by the nanoparticle. The result is the constant quantum flux of copper which manifests and establishes the antimicrobial environment preventing or inhibiting the growth of bacteria. The presence of CuQ results in inhibiting or delaying bacterial destruction and endogenous enzymatic breakdown of the zone of resin inter-diffusion, the integrity of which is essential for dental restoration longevity.

  9. Post-annealing effect on the room-temperature ferromagnetism in Cu-doped ZnO thin films

    SciTech Connect

    Hu, Yu-Min Kuang, Chein-Hsiun; Han, Tai-Chun; Yu, Chin-Chung; Li, Sih-Sian

    2015-05-07

    In this work, we investigated the structural and magnetic properties of both as-deposited and post-annealed Cu-doped ZnO thin films for better understanding the possible mechanisms of room-temperature ferromagnetism (RT-FM) in ZnO-based diluted magnetic oxides. All of the films have a c-axis-oriented wurtzite structure and display RT-FM. X-ray photoelectron spectroscopy results showed that the incorporated Cu ions in as-deposited films are in 1+ valence state merely, while an additional 2+ valence state occurs in post-annealed films. The presence of Cu{sup 2+} state in post-annealed film accompanies a higher magnetization value than that of as-deposited film and, in particular, the magnetization curves at 10 K and 300 K of the post-annealed film separate distinctly. Since Cu{sup 1+} ion has a filled 3d band, the RT-FM in as-deposited Cu-doped ZnO thin films may stem solely from intrinsic defects, while that in post-annealed films is enhanced due to the presence of CuO crystallites.

  10. An In-Situ XAS Study of the Structural Changes in a CuO-CeO2/Al2O3 Catalyst during Total Oxidation of Propane

    SciTech Connect

    Silversmith, Geert; Poelman, Hilde; Poelman, Dirk; Gryse, Roger de; Olea, Maria; Balcaen, Veerle; Heynderickx, Philippe; Marin, Guy B.

    2007-02-02

    A CuOx-CeOx/Al2O3 catalyst was studied with in-situ transmission Cu K XAS for the total oxidation of propane as model reaction for the catalytic elimination of volatile organic compounds. The local Cu structure was determined for the catalyst as such, after pre-oxidation and after reduction with propane. The catalyst as such has a local CuO structure. No structural effect was observed upon heating in He up to 600 deg. C or after pre-oxidation at 150 deg. C. A full reduction of the Cu2+ towards metallic Cu0 occurred, when propane was fed to the catalyst. The change in local Cu structure during propane reduction was followed with a time resolution of 1 min. The {chi}(k) scans appeared as linear combinations of start and end spectra, CuO and Cu structure, respectively. However, careful examination of the XANES edge spectra indicates the presence of a small amount of additional Cu1+ species.

  11. A facile strategy to fabricate plasmonic Cu modified TiO{sub 2} nano-flower films for photocatalytic reduction of CO{sub 2} to methanol

    SciTech Connect

    Liu, Enzhou; Qi, Lulu; Bian, Juanjuan; Chen, Yihan; Hu, Xiaoyun; Fan, Jun; Liu, Hanchen; Zhu, Changjun; Wang, Qiuping

    2015-08-15

    Graphical abstract: Photoreduction of CO{sub 2} to CH{sub 3}OH over plasmonic Cu/TiO{sub 2} film. - Highlights: • Cu nanoparticles modified TiO{sub 2} nano-flower film was prepared by a facile strategy. • Cu nanoparticles can enhance the light absorption and the Raman scattering of TiO{sub 2}. • Cu nanoparticles can effectively restrain the recombination of the charge carriers. • A synergistic mechanism is proposed for photocatalytic reduction of CO{sub 2} on Cu/TiO{sub 2} film. - Abstract: Cu nanoparticles (NPs) deposited TiO{sub 2} nano-flower films were fabricated using a combination of a hydrothermal method and a microwave-assisted reduction process. The investigations indicated that Cu NPs and TiO{sub 2} film both exhibit visible light harvesting properties based on localized surface plasmon resonance (LSPR) of Cu NPs and unique nanostructures of TiO{sub 2} film. Fluorescence quenching was observed because the recombination of charge carriers was effectively suppressed by Cu NPs deposition. The experimental results indicate that Cu/TiO{sub 2} films exhibit better activity for the photocatalytic reduction of CO{sub 2} due to the charge transfer property and LSPR effect of Cu NPs. The CH{sub 3}OH production rate reached 1.8 μmol cm{sup −2} h{sup −1} (energy efficiency was 0.8%) over 0.5 Cu/TiO{sub 2} film under UV and visible light irradiation, which was 6.0 times higher than that observed over pure TiO{sub 2} film. In addition, a tentative photocatalytic mechanism is proposed to understand the experimental results over the Cu modified TiO{sub 2} nano-flower films.

  12. Copper doping of ZnO crystals by transmutation of {sup 64}Zn to {sup 65}Cu: An electron paramagnetic resonance and gamma spectroscopy study

    SciTech Connect

    Recker, M. C.; McClory, J. W. Holston, M. S.; Golden, E. M.; Giles, N. C.; Halliburton, L. E.

    2014-06-28

    Transmutation of {sup 64}Zn to {sup 65}Cu has been observed in a ZnO crystal irradiated with neutrons. The crystal was characterized with electron paramagnetic resonance (EPR) before and after the irradiation and with gamma spectroscopy after the irradiation. Major features in the gamma spectrum of the neutron-irradiated crystal included the primary 1115.5 keV gamma ray from the {sup 65}Zn decay and the positron annihilation peak at 511 keV. Their presence confirmed the successful transmutation of {sup 64}Zn nuclei to {sup 65}Cu. Additional direct evidence for transmutation was obtained from the EPR of Cu{sup 2+} ions (where {sup 63}Cu and {sup 65}Cu hyperfine lines are easily resolved). A spectrum from isolated Cu{sup 2+} (3d{sup 9}) ions acquired after the neutron irradiation showed only hyperfine lines from {sup 65}Cu nuclei. The absence of {sup 63}Cu lines in this Cu{sup 2+} spectrum left no doubt that the observed {sup 65}Cu signals were due to transmuted {sup 65}Cu nuclei created as a result of the neutron irradiation. Small concentrations of copper, in the form of Cu{sup +}-H complexes, were inadvertently present in our as-grown ZnO crystal. These Cu{sup +}-H complexes are not affected by the neutron irradiation, but they dissociate when a crystal is heated to 900 °C. This behavior allowed EPR to distinguish between the copper initially in the crystal and the copper subsequently produced by the neutron irradiation. In addition to transmutation, a second major effect of the neutron irradiation was the formation of zinc and oxygen vacancies by displacement. These vacancies were observed with EPR.

  13. Detection of Cu{sub 2}Zn{sub 5}SnSe{sub 8} and Cu{sub 2}Zn{sub 6}SnSe{sub 9} phases in co-evaporated Cu{sub 2}ZnSnSe{sub 4} thin-films

    SciTech Connect

    Schwarz, Torsten Cojocaru-Mirédin, Oana; Raabe, Dierk; Choi, Pyuck-Pa; Marques, Miguel A. L.; Botti, Silvana; Mousel, Marina; Redinger, Alex; Siebentritt, Susanne

    2015-10-26

    Cu{sub 2}ZnSnSe{sub 4} thin-films for photovoltaic applications are investigated using combined atom probe tomography and ab initio density functional theory. The atom probe studies reveal nano-sized grains of Cu{sub 2}Zn{sub 5}SnSe{sub 8} and Cu{sub 2}Zn{sub 6}SnSe{sub 9} composition, which cannot be assigned to any known phase reported in the literature. Both phases are considered to be metastable, as density functional theory calculations yield positive energy differences with respect to the decomposition into Cu{sub 2}ZnSnSe{sub 4} and ZnSe. Among the conceivable crystal structures for both phases, a distorted zinc-blende structure shows the lowest energy, which is a few tens of meV below the energy of a wurtzite structure. A band gap of 1.1 eV is calculated for both the Cu{sub 2}Zn{sub 5}SnSe{sub 8} and Cu{sub 2}Zn{sub 6}SnSe{sub 9} phases. Possible effects of these phases on solar cell performance are discussed.

  14. The effect of Cu/Zn molar ratio on CO{sub 2} hydrogenation over Cu/ZnO/ZrO{sub 2}/Al{sub 2}O{sub 3} catalyst

    SciTech Connect

    Shaharun, Salina E-mail: maizats@petronas.com.my; Shaharun, Maizatul S. E-mail: maizats@petronas.com.my; Taha, Mohd F.; Mohamad, Dasmawati

    2014-10-24

    Catalytic hydrogenation of carbon dioxide (CO{sub 2}) to methanol is an attractive way to recycle and utilize CO{sub 2}. A series of Cu/ZnO/Al{sub 2}O{sub 3}/ZrO{sub 2} catalysts (CZAZ) containing different molar ratios of Cu/Zn were prepared by the co-precipitation method and investigated in a stirred slurry autoclave system. The catalysts were characterized by temperature-programmed reduction (TPR), field emission scanning electron microscopy-energy dispersive analysis (FESEM-EDX), X-ray diffraction (XRD) and N{sub 2} adsorption-desorption. Higher surface area, SA{sub BET} values (42.659.9 m{sup 2}/g) are recorded at low (1) and high (5) Cu/Zn ratios with the minimum value of 35.71 m{sup 2}/g found for a Cu/Zn of 3. The reducibility of the metal oxides formed after calcination of catalyst samples was also affected due to change in metal-support interaction. At a low reaction temperature of 443 K, total gas pressure of 3.0 MPa and 0.1 g/mL of the CZAZ catalyst, the selectivity to methanol decreased as the Cu/Zn molar ratio increased, and the maximum selectivity of 67.73 was achieved at Cu/Zn molar ratio of 1. With a reaction time of 3h, the best performing catalyst was CZAZ75 with Cu/Zn molar ratio of 5 giving methanol yield of 79.30%.

  15. Syntheses, Structure, Magnetism, and Optical Properties of the Ordered Interlanthanide Copper Chalcogenides Ln{sub 2}YbCuQ{sub 5} (Ln = La, Ce, Pr, Nd, Sm; Q = S, Se): Evidence for Unusual Magnetic Ordering in Sm{sub 2}YbCuS{sub 5}

    SciTech Connect

    Jin, Geng Bang; Choi, Eun Sang; Guertin, Robert P.; Booth, Corwin H.; Albrecht-Schmitt, Thomas E.

    2010-11-19

    Ln{sub 2}YbCuQ{sub 5} (Ln = La, Ce, Pr, Nd, Sm; Q = S, Se) have been prepared by direct reaction of the elements in Sb{sub 2}Q{sub 3} (Q = S, Se) fluxes at 900 °C. All compounds have been characterized by single-crystal X-ray diffraction methods and they are isotypic. The structure of Ln{sub 2}YbCuQ{sub 5} consists of one-dimensional {sup 1}{sub {infinity}} [YbCuQ{sub 5}]{sup 6-} ribbons extending along the b axis that are connected by larger Ln{sup 3+} ions. Each ribbon is constructed from two single chains of [YbQ{sub 6}] octahedra with one double chain of [CuQ{sub 5}] trigonal bipyramids in the middle. All three chains connect with each other via edge-sharing. There are two crystallographically unique Ln atoms, one octahedral Yb site, and two disordered Cu positions inside of distorted Q{sub 5} trigonal bipyramids. Both Ln atoms are surrounded by eight Q atoms in bicapped trigonal prisms. The magnetic properties of Ln{sub 2}YbCuQ{sub 5} have been characterized using magnetic susceptibility and heat capacity measurements, while their optical properties have been explored using UV-vis-NIR diffuse reflectance spectroscopy. Cesub 2}YbCuSe{sub 5}, La{sub 2}YbCuS{sub 5}, Ce{sub 2}YbCuS{sub 5}, and Pr{sub 2}YbCuS{sub 5} are Curie-Weiss paramagnets. La{sub 2}YbCuSe{sub 5} and Nd{sub 2}YbCuS{sub 5} show evidence for short-range antiferromagnetic ordering at low temperatures. Sm{sub 2}YbCuS{sub 5} shows magnetic ordering at 5.9 K, followed by negative magnetization at low external fields. The band gaps of La{sub 2}YbCuSe{sub 5}, Ce{sub 2}YbCuSe{sub 5}, La{sub 2}YbCuS{sub 5}, Ce{sub 2}YbCuS{sub 5}, Pr{sub 2}YbCuS{sub 5}, Nd{sub 2}YbCuS{sub 5},and Sm{sub 2}YbCuS{sub 5} are 1.15 eV, 1.05 eV, 1.45 eV, 1.37 eV, 1.25 eV, 1.35 eV, and 1.28 eV respectively.

  16. Influence of synthesis condition on product formation: hydrothermal auto-oxidated synthesis of five copper halides with ratio of Cu(I)/Cu(II) in 1:1, 2:1, 3:1, 4:1 and 1:0

    SciTech Connect

    Zhang Shuai; Cao Yanning; Zhang Hanhui Chai Xiaochuan; Chen Yiping; Sun Ruiqing

    2008-12-15

    The hydrothermal synthesis and structural characterization of five copper iodides derived from chelated ligands, 1, 10-phenanthroline (phen), ethylenediamine (en) and 1, 3-propanediamine, are reported. Except monovalent copper compound 1 ((phen)Cu{sub 3}I{sub 3}1), other four compounds ([Cu(phen){sub 2}I][CuI{sub 2}] 2, [Cu(phen){sub 2}I][Cu{sub 3}I{sub 4}] 3, [Cu(en){sub 2}][Cu{sub 4}(phen){sub 2}I{sub 6}] 4 and [Cu(1, 3-propanediamine){sub 2}][CuI{sub 2}]{sub 2}5) are mixed-valent Cu(I)-Cu(II) compounds by partially auto-oxidated from Cu(I). Supramolecular frameworks of these compounds can be assembled by C/N-H...I hydrogen bonds, Cu(I)-Cu(I) interaction, weak Cu-I semicoordinate interaction, C-H...{pi} and {pi}-{pi} stacking interactions. It's noteworthy that we find hydrothermal synthesis under higher pH value, higher synthesis temperature and longer reaction time can obtain higher ratio of Cu(I)/Cu(II) copper iodides and organic ligand with lower steric hinderance is prone to coordinated with divalent copper to form cation unit. Finally, the fluorescent study shows 1 exhibits intense orange-red luminescence with long lifetime at 293 K and more intense emission and longer lifetime at 77 K. Moreover, the room temperature EPR spectra of above five compounds not only show the valence of copper but demonstrate the coordination environment of Cu(II) centre. - Graphical abstract: The influence of hydrothermal synthesis condition on the ratio of Cu(I)/Cu(II) of five copper iodides, with 1:0, 1:1, 3:1, 4:1, 2:1, respectively, is deduced and the rivalrousness of 1,10-phenanthroline, ethylenediamine and 1, 3-propanediamine is discussed as well. The fluorescent study shows 1 exhibits intense orange-red luminescence with long lifetime ({tau}=1.25 {mu}s) at 293 K and more intense emission and longer lifetime({tau}=6.95 {mu}s) at 77 K.

  17. Noncentrosymmetric rare-earth copper gallium chalcogenides RE{sub 3}CuGaCh{sub 7} (RE=La–Nd; Ch=S, Se): An unexpected combination

    SciTech Connect

    Iyer, Abishek K.; Rudyk, Brent W.; Lin, Xinsong; Singh, Harpreet; Sharma, Arzoo Z.; Wiebe, Christopher R.; Mar, Arthur

    2015-09-15

    The quaternary rare-earth chalcogenides RE{sub 3}CuGaS{sub 7} and RE{sub 3}CuGaSe{sub 7} (RE=La–Nd) have been prepared by reactions of the elements at 1050 °C and 900 °C, respectively. They crystallize in the noncentrosymmetric La{sub 3}CuSiS{sub 7}-type structure (hexagonal, space group P6{sub 3}, Z=2) in which the a-parameter is largely controlled by the RE component (a=10.0–10.3 Å for the sulfides and 10.3–10.6 Å for the selenides) whereas the c-parameter is essentially fixed by the choice of Ga and chalcogen atoms within tetrahedral units (c=6.1 Å for the sulfides and 6.4 Å for the selenides). They extend the series RE{sub 3}MGaCh{sub 7}, previously known for divalent metal atoms (M=Mn–Ni), differing in that the Cu atoms in RE{sub 3}CuGaCh{sub 7} occupy trigonal planar sites instead of octahedral sites. Among quaternary chalcogenides RE{sub 3}MM′Ch{sub 7}, the combination of monovalent (M=Cu) and trivalent (M′=Ga) metals is unusual because it appears to violate the condition of charge balance satisfied by most La{sub 3}CuSiS{sub 7}-type compounds. The possibility of divalent Cu atoms was ruled out by bond valence sum analysis, magnetic measurements, and X-ray photoelectron spectroscopy. The electron deficiency in RE{sub 3}CuGaCh{sub 7} is accommodated through S-based holes at the top of the valence band, as shown by band structure calculations on La{sub 3}CuGaS{sub 7}. An optical band gap of about 2.0 eV was found for La{sub 3}CuGaSe{sub 7}. - Graphical abstract: The chalcogenides RE{sub 3}CuGaCh{sub 7} contain monovalent Cu in trigonal planes and trivalent Ga in tetrahedra; they are electron-deficient representatives of La{sub 3}CuSiS{sub 7}-type compounds, which normally satisfy charge balance. - Highlights: • Quaternary chalcogenides RE{sub 3}CuGaCh{sub 7} (RE=La–Nd; Ch=S, Se) were prepared. • Bond valence sums, magnetism, and XPS data give evidence for monovalent Cu. • Crystal structures reveal high anisotropy of Cu displacement.

  18. Manufacturable CuIn(Ga)Se{sub 2}-based solar cells via development of co-sputtered CuInSe{sub 2} absorber layers

    SciTech Connect

    Dr. Ingrid Eisgruber

    1999-03-20

    Yield and reproducibility remain issues in CuIn(Ga)Se{sub 2} (CIGS) photovoltaic module fabrication. While small-area cells (<1 cm{sup 2}) over 18% efficient have been reported, the best large-area manufactured devices (>1 ft{sup 2}) are 11% efficient with about 60% yield. If improvements in large-area manufacturing can accomplish 15% efficiency and 90% yield, the result is a doubling in throughput leading to a reduction in cost per watt of over 50%. The challenge now facing the photovoltaics industry is to bring the efficiencies of small-area cells and large-area industrial modules closer together and to raise manufacturing yields.

  19. Overview spectra and axial distribution of spectral line intensities in a high-current vacuum arc with CuCr electrodes

    SciTech Connect

    Lisnyak, M.; Pipa, A. V.; Gorchakov, S. E-mail: weltmann@inp-greifswald.de; Iseni, S.; Franke, St.; Khapour, A.; Methling, R.; Weltmann, K.-D. E-mail: weltmann@inp-greifswald.de

    2015-09-28

    Spectroscopic investigations of free-burning vacuum arcs in diffuse mode with CuCr electrodes are presented. The experimental conditions of the investigated arc correspond to the typical system for vacuum circuit breakers. Spectra of six species Cu I, Cu II, Cu III, Cr I, Cr II, and Cr III have been analyzed in the wavelength range 350–810 nm. The axial intensity distributions were found to be strongly dependent on the ionization stage of radiating species. Emission distributions of Cr II and Cu II can be distinguished as well as the distributions of Cr III and Cu III. Information on the axial distribution was used to identify the spectra and for identification of overlapping spectral lines. The overview spectra and some spectral windows recorded with high resolution are presented. Analysis of axial distributions of emitted light, which originates from different ionization states, is presented and discussed.

  20. Synthesis and Evaluation of Cu-SAPO-34 Catalysts for Ammonia Selective Catalytic Reduction. 1. Aqueous Solution Ion Exchange

    SciTech Connect

    Gao, Feng; Walter, Eric D.; Washton, Nancy M.; Szanyi, Janos; Peden, Charles HF

    2013-09-06

    SAPO-34 molecular sieves are synthesized using various structure directing agents (SDAs). Cu-SAPO-34 catalysts are prepared via aqueous solution ion exchange. Catalysts are characterized with surface area/pore volume measurements, temperature programmed reduction (TPR), electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopies. Catalytic properties are examined using standard ammonia selective catalytic reduction (NH3-SCR) and ammonia oxidation reactions. During solution ion exchange, different SAPO-34 samples undergo different extent of structural damage via irreversible hydrolysis. Si content within the samples (i.e., Al-O-Si bond density) and framework stress are key factors that affect irreversible hydrolysis. Even using very dilute Cu acetate solutions, it is not possible to generate Cu-SAPO-34 samples with only isolated Cu2+ ions. Small amounts of CuOx species always coexist with isolated Cu2+ ions. Highly active and selective Cu-SAPO-34 catalysts for NH3-SCR are readily generated using this synthesis protocol, even for SAPO-34 samples that degrade substantially during solution ion exchange. High-temperature aging is found to improve the catalytic performance. This is likely due to reduction of intracrystalline mass-transfer limitations via formation of additional porosity in the highly defective SAPO-34 particles formed after ion exchange. The authors gratefully acknowledge the US Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy, Office of Vehicle Technologies for the support of this work. The research described in this paper was performed at the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOEs Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated for the US DOE by Battelle Memorial Institute under contract number DE-AC05-76RL01830.

  1. X-ray-absorption study of CuBr at high pressure

    SciTech Connect

    Tranquada, J.M.; Ingalls, R.

    1986-09-15

    The x-ray-absorption spectrum of cuprous bromide has been measured as a function of pressure. The x-ray-absorption near-edge structure proved to be an excellent indicator of high-pressure phase transitions in this material. The normalized ''white-line'' peak heights at both the Cu and Br K-italic edges decreased on entering the tetragonal phase and increased in going to the NaCl structure. The zinc-blende to tetragonal phase transition took place over a very narrow pressure range centered at 46 +- 5 kbar. The transformation from the tetragonal to the NaCl structure, on the other hand, showed a broad mixed-phase region, suggesting a nucleation-and-growth mechanism for the transition. The mixed-phase region was centered at 75 +- 6 kbar. No evidence of a phase between the zinc-blende and tetragonal phases was observed, presumably because it does not exist. Analysis of the extended x-ray-absorption fine-structure (EXAFS) clearly showed that there is no change in coordination in going from the zinc-blende to the tetragonal phase although the nearest-neighbor distance increases slightly. A much larger increase in R-italic/sub 1/ occurs at the transition to the NaCl structure, where the coordination increases from 4 to 6. The mean-square deviation in the nearest-neighbor bond length, sigma/sub 1//sup 2/, appears to be a fairly smooth function of nearest-neighbor distance, decreasing (or increasing) as R-italic/sub 1/ decreases (or increases) more or less independent of structure. Evidence from the literature was presented to suggest that the zinc-blende to tetragonal transition in CuBr (and also CuCl) should occur by shear deformation.

  2. Electron scattering mechanisms in Cu-Mn films for interconnect applications

    SciTech Connect

    Misjk, F.; Nagy, K. H.; Radnczi, G.; Lobotka, P.

    2014-08-28

    Electrical properties and corresponding structural features of Cu-Mn alloy films with potential application as barrier and interconnect layers were studied. Cu-Mn films were deposited by DC magnetron sputtering at room temperature on SiO{sub 2} substrates. Electrical resistivity measurements were made as a function of film composition and temperature. The specific resistivity varies linearly with the Mn content showing a maximum of 205???cm at 80 at. % Mn. The temperature coefficient of resistance (TCR) of all alloy films is low, showing non-metallic conductivity for most compositions. Also a minimum TCR has been observed in the 4080 at. % Mn range which was attributed to a magnetic transformation around 200300?K. Electrical resistivity measurements are correlated with the film structure revealed by transmission electron microscopy to clarify the phase regions throughout the composition range. In the 2040 at. % and 7080 at. % Mn ranges, two-phase structures were identified, where Cu- or Mn-rich solid solution grains were surrounded by a thin amorphous covering layer. Based on the revealed phase regions and morphologies electron scattering mechanisms in the system were evaluated by combining the Matthiessen's rule and the Mayadas-Schatzkes theory. Grain boundary reflectivity coefficients (r?=?0.60.8) were calculated from fitting the model to the measurements. The proposed model indicates that, in a binary system, the special arrangement of the two phases results in new scattering mechanisms. The results are of value in optimizing the various parameters needed to produce a suitable barrier layer.

  3. Shape memory properties and microstructural evolution of rapidly solidified CuAlBe alloys

    SciTech Connect

    Ergen, Semra; Uzun, Orhan; Yilmaz, Fikret; Kiliaslan, M. Fatih

    2013-06-15

    In this work, the effects of Be addition on the microstructure and phase transformation temperatures of Cu12AlxBe (x = 0.4, 0.5 and 0.6 wt.%) shape memory alloys fabricated by using the arc-melting and melt-spinning techniques have been investigated. X-ray diffraction analysis revealed that the arc-melted alloys consisted of austenitic ?{sub 1}, martensitic ?{sub 1}? and ?{sub 2} precipitate phases, whereas melt-spun ribbons were composed of a fully martensitic phase. The average grain size of martensitic phases in melt-spun ribbons was determined by electron microscopy images, showing a decrease with increasing Beryllium (Be) amount. Moreover, it was found that the Be addition in the arc-melted alloys had a distinct effect on the morphology of the ?{sub 2} precipitate phase. Transmission electron microscopy analysis showed that the thickness of martensitic plates in the melt-spun ribbons reduced with increasing Be addition. In a differential scanning calorimeter analysis, no martensitic transformation (M{sub s}) peak was observed in arc-melted alloys, but it was clearly detected in melt-spun ribbons, in which M{sub s} decreased dramatically with increasing Be addition. The improvement in the shape memory ability of melt-spun ribbons was explained in terms of the refinement in grain size and martensitic plates. - Highlights: The CuAlBe SMAs were produced by means of arc-melter and melt-spinner techniques. MT was directly obtained in melt-spuns without any intermediate process. The transformation temperatures decreased with increasing Be amount. The thickness of martensitic plates in the ribbons reduced with increasing Be. SMP of CuAl was improved by the addition of Be together with rapid solidification.

  4. Bi-Sr-Ca-Cu-O surface studied by means of scanning tunnelling microscope

    SciTech Connect

    Witek, A.; Dabkowski, A.; Rauluszkiewicz, J.

    1989-03-10

    Surface topography of the high-T/sub c/ superconductor BiSrCaCu/sub 2/O/sub x/ has been investigated by means of scanning tunnelling microscope. The measurements were performed on the natural surface of ceramics material in air at room temperature. It can be deduced from the surface images, that bulk orthorhombic crystal structure extends to the surface. The surface seems to be uniform metallic in character and not drastically contaminated. Regular steps observed on the surface correspond to the dimension of the unit cell in z direction or its multiples.

  5. Shell Model Description of the Odd-Odd Co and Cu Nuclei

    SciTech Connect

    Medina, N. H.; Allegro, P. R. P.; Oliveira, J. R. B. de; Ribas, R. V.; Seale, W. A.; Toufen, D. L.; Silveira, M. A. G.

    2007-10-26

    The known excited states of the odd-odd nuclei {sup 54,56,58,60}Co and 60,62,64,66Cu were interpreted in the framework of the large scale shell model (LSSM), using several effective interactions and configuration spaces. For the description of the negative parity states, we have allowed one particle excitation to the g{sub 9/2} orbital. The LSSM using the GXPF1 effective interaction reproduces well the first excited states in all of these nuclei.

  6. L X-ray Production Cross Sections for Proton Impact on Fe, Cu, Zn, and Ge

    SciTech Connect

    Cipolla, Sam J.

    2009-03-10

    L x-rays excited by 50-minus;300 keV protons impacting thick targets of Fe, Cu, Zn, and Ge were measured with a high-resolution Si(Li) detector equipped with an ultra-thin window. L{sub l,{eta}}, L{sub {alpha}}{sub ,{beta}}{sub 1}, and L{sub {beta}}{sub 3,4} x-ray yields were derived from peak-fitting analysis of the measured x-ray spectra. The corresponding L{sub 1} and L{sub 2}+L{sub 3} sub-shell cross sections were compared with predictions of the ECPSSR theory.

  7. Flux pinning by precipitates in the Bi-Sr-Ca-Cu-O system

    DOEpatents

    Shi, Donglu

    1992-01-01

    A fundamental pinning mechanism has been identified in the Bi-Sr-Ca-Cu-O system. The pinning strength has been greatly increased by the introduction of calcium- and copper-rich precipitates into the sample matrix. The calcium and copper are supersaturated in the system by complete melting, and the fine calcium and copper particles precipitated during subsequent crystallization anneal to obtain the superconducting phases. The intragrain critical current density has been increased from the order of 10.sup.5 A/cm.sup.2 to 10.sup.7 A/cm.sup.2 at 5 T.

  8. Pb, Cu, and Zn distributions at humic acid-coated metal-oxide surfaces

    DOE PAGES [OSTI]

    Wang, Yingge; Michel, F. Marc; Choi, Yongseong; Eng, Peter J.; Levard, Clement; Siebner, Hagar; Gu, Baohua; Bargar, John R.; Brown, Gordon E.

    2016-05-09

    Here, mineral surfaces are often coated by natural organic matter (NOM), which has a major influence on metal-ion sorption and sequestration because of the abundance of binding sites in such coatings and the changes they cause in local nanoscale environments. The effects of NOM coatings on mineral surfaces are, however, still poorly understood at the molecular level due to the complexity of these systems. In this study, we have applied long-period X-ray standing wave-fluorescence yield (LP-XSW-FY) spectroscopy to measure the partitioning of naturally present Cu(II) (0.0226%), Zn(II) (0.009%), and Pb(II) ( 0.0004%) between Elliott Soil Humic Acid (ESHA) coatings andmore » three model single-crystal metal-oxide substrates: α-Al2O3 (0 0 0 1), α-Al2O3 (1 1 0 2), and α-Fe2O3 (0 0 0 1). The competitive sorption effects among these metal ions for binding sites in the ESHA coatings and on the metal-oxide surfaces were investigated as a function of reaction time, calcium content, and solution pH. Pb(II) ions present in the ESHA coatings were found to redistribute to reactive α-Al2O3 (1 1 0 2) and α-Fe2O3 (0 0 0 1) surfaces after 3 h of reaction (pH = 6.0, [Ca(II)] = 2 mM). Pb(II) partitioning onto these reactive metal-oxide surfaces increased with increasing reaction time (up to 7 d). In addition, the partitioning of Cu(II) and Zn(II) from the ESHA coating to the α-Fe2O3 (0 0 0 1) substrate increased slightly with reaction time (2.4% and 3.7% for Cu(II) and Zn(II), respectively, after 3 h and 6.4% and 7.7% for Cu(II) and Zn(II), respectively, after 72 h of reaction time).« less

  9. Surface relief produced by diffusion induced boundary migration in Cu-Zn

    SciTech Connect

    Tsai, Y.S.; Meyrick, G.; Shewmon, P.G.

    1984-03-01

    Experimental observations are presented that demonstrate that diffusion induced grain boundary migration in copper foils exposed to zinc vapor, from a Cu-15 pct Zn alloy, can be studied directl after treatment without etching. The general characteristics of migration are in accord with previous investigations, but novel changes in the surface topography are described. Pits were formed on the surface of areas swept by boundary migration; also, the surface was often converted into a series of corrugations. The formation of pits suggests that the grain boundary diffusivity of zinc exceeds that of copper. The corrugations are believed to indicate that boundaries sometimes move in an intermittent manner.

  10. Physisorbed H{sub 2}@Cu(100) surface: Potential and spectroscopy

    SciTech Connect

    Bernard, Eddy; Houriez, Céline; Mitrushchenkov, Alexander O.; Guitou, Marie; Chambaud, Gilberte

    2015-02-07

    Using an embedding approach, a 2-D potential energy function has been calculated to describe the physisorption interaction of H{sub 2} with a Cu(100) surface. For this purpose, a cluster model of the system calculated with highly correlated wavefunctions is combined with a periodic Density-Functional-Theory method using van der Waals-DF2 functional. Rotational and vibrational energy levels of physisorbed H{sub 2}, as well as D{sub 2} and HD, are calculated using the 2D embedding corrected potential energy function. The calculated transitions are in a very good agreement with Electron-Energy-Loss-Spectroscopy observations.

  11. La??xSrxCuO? superconductor nanowire devices

    SciTech Connect

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

    2014-07-02

    La??xSrxCuO? 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.

  12. La2-xSrxCuO4 superconductor nanowire devices

    DOE PAGES [OSTI]

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

    2014-07-02

    La2-xSrxCuO₄ nanowire devices have been fabricated and characterized using electrical transport measurements. In addition, 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.

  13. Multiscale twin hierarchy in NiMnGa shape memory alloys with Fe and Cu

    SciTech Connect

    Barabash, Rozaliya I.; Barabash, Oleg M.; Popov, Dmitry; Shen, Guoyin; Park, Changyong; Yang, Wenge

    2015-01-31

    X-ray microdiffraction and scanning electron microscopy studies reveal 10 M martensitic structure with a highly correlated multiscale twin hierarchy organization in NiMnGaFeCu shape memory alloys. In this paper, high compatibility is found at the twin interfaces resulting in a highly correlated twinned lattice orientation across several laminate levels. The lattice unit cell is described as monoclinic I-centered with a = 4.28 Å, b = 4.27 Å, c = 5.40 Å, γ = 78.5°. The modulation is found parallel to the b axis. Finally, thin tapered needle-like lamellae and branching are observed near the twin boundaries.

  14. Nanostructured Cu-Cr alloy with high strength and electrical conductivity

    SciTech Connect

    Islamgaliev, R. K. Nesterov, K. M.; Bourgon, J.; Champion, Y.; Valiev, R. Z.

    2014-05-21

    The influence of nanostructuring by high pressure torsion (HPT) on strength and electrical conductivity in the Cu-Cr alloy has been investigated. Microstructure of HPT samples was studied by transmission electron microscopy with special attention on precipitation of small chromium particles after various treatments. Effect of dynamic precipitation leading to enhancement of strength and electrical conductivity was observed. It is shown that nanostructuring leads to combination of high ultimate tensile strength of 790–840 MPa, enhanced electrical conductivity of 81%–85% IACS and thermal stability up to 500 °C. The contributions of grain refinement and precipitation to enhanced properties of nanostructured alloy are discussed.

  15. ScanningTunneling Luminescence of Grain Boundaries in Cu(In,Ga)Se2

    SciTech Connect

    Romero, M. J.; Jiang, C.-S.; Al-Jassim, M. M.; Noufi, R.

    2005-01-01

    At the Laboratory, photon emission in semiconductors has been mapped in the nanoscale using scanning tunneling microscopy (STM). In this Solar Program Review Meeting, we report on the latest results obtained in Cu(In,Ga)Se2 (CIGS) thin films by this adapted STM. Scanning tunneling luminescence (STL) spectroscopy suggests that photons are emitted near the surface of CIGS. STL is excited either by (1) diffusion of tunneling electrons and subsequent recombination with available holes in CIGS or (2) impact ionization by hot electrons. Which process becomes predominant depends on the voltage applied to the STM tip. Photon mapping shows electronically active, extended defects near the surface of CIGS thin films.

  16. Magnetic order in RBa/sub 2/Cu/sub 2/O/sub 6+//sub x/ (invited)

    SciTech Connect

    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. Shape controlled synthesis of Cu{sub 2}O and its catalytic application to synthesize amorphous carbon nanofibers

    SciTech Connect

    Du Fanglin Liu Jungang; Guo Zhiyan

    2009-01-08

    Octahedral Cu{sub 2}O particles and Cu{sub 2}O nanowires were synthesized by a simple solution-phase route using N{sub 2}H{sub 4}.H{sub 2}O as reducing agent at room temperature. Amorphous carbon nanofibers were synthesized using octahedral Cu{sub 2}O particles and an acetylene gas source at atmospheric pressure. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric (TG) analysis. SEM and TEM images indicated that most of the obtained octahedral Cu{sub 2}O particles had an edge length of 400-700 nm. The obtained nanowires had uniform diameters of about 15 nm, and the length of the nanowires ranged from 5 to 10 {mu}m. The XRD result revealed the amorphous feature of the nanofibers. IR spectrum revealed that the nanofibers consist of -CH, -CH{sub 2,} -C=C- and -CH{sub 3} groups. The concentrations of N{sub 2}H{sub 4}.H{sub 2}O and NaOH played important roles in controlling the geometric shape of the Cu{sub 2}O.

  18. Catalytic conversion of syngas to mixed alcohols over Zn-Mn promoted Cu-Fe based catalyst

    DOE PAGES [OSTI]

    Lu, Yongwu; Yu, Fei; Hu, Jin; Liu, Jian

    2012-04-12

    Zn-Mn promoted Cu-Fe based catalyst was synthesized by the co-precipitation method. Mixed alcohols synthesis from syngas was studied in a half-inch tubular reactor system after the catalyst was reduced. Zn-Mn promoted Cu-Fe based catalyst was characterized by SEM-EDS, TEM, XRD, and XPS. The liquid phase products (alcohol phase and hydrocarbon phase) were analyzed by GC-MS and the gas phase products were analyzed by GC. The results showed that Zn-Mn promoted Cu-Fe based catalyst had high catalytic activity and high alcohol selectivity. The maximal CO conversion rate was 72%, and the yield of alcohol and hydrocarbons were also very high. Cumore » (111) was the active site for mixed alcohols synthesis, Fe2C (101) was the active site for olefin and paraffin synthesis. The reaction mechanism of mixed alcohols synthesis from syngas over Zn-Mn promoted Cu-Fe based catalyst was proposed. Here, Zn-Mn promoted Cu-Fe based catalyst can be regarded as a potential candidate for catalytic conversion of biomass-derived syngas to mixed alcohols.« less

  19. Impact of sulfation and desulfation on NOx reduction using Cu-chabazite SCR catalysts

    SciTech Connect

    Brookshear, Daniel William; Nam, Jeong -Gil; Nguyen, Ke; Toops, Todd J.; Binder, Andrew J.

    2015-06-05

    This bench reactor study investigates the impact of gaseous sulfur on the NOx reduction activity of Cu-chabazite SCR (Cu-CHA) catalysts at SO2 concentrations representative of marine diesel engine exhaust. After two hours of 500 ppm SO2 exposure at 250 and 400 °C in the simulated diesel exhaust gases, the NOx reduction activity of the sulfated Cu-CHA SCR catalysts is severely degraded at evaluation temperatures below 250 °C; however, above 250 °C the impact of sulfur exposure is minimal. EPMA shows that sulfur is located throughout the washcoat and along the entire length of the sulfated samples. Interestingly, BET measurements reveal that the sulfated samples have a 20% decrease in surface area. Moreover, the sulfated samples show a decrease in NOx/nitrate absorption during NO exposure in a DRIFTS reactor which suggests that Cu sites in the catalyst are blocked by the presence of sulfur. SO2 exposure also results in an increase in NH3 storage capacity, possibly due to the formation of ammonium sulfate species in the sulfated samples. In all cases, lean thermal treatments as low as 500 °C reverse the effects of sulfur exposure and restore the NOx reduction activity of the Cu-CHA catalyst to that of the fresh condition.

  20. ESR of Gd{sup 3+} in the Kondo-lattice compound YbAgCu{sub 4} and its reference compounds RAgCu{sub 4} (R=Y,Lu)

    SciTech Connect

    Pagliuso, P.G.; Rettori, C.; Oseroff, S.B.; Sarrao, J.; Fisk, Z.; Cornelius, A.; Hundley, M.F.

    1997-10-01

    Low-temperature (T{lt}30thinspK) electron-spin-resonance (ESR) experiments of Gd{sup 3+} diluted in the Kondo-lattice compound YbAgCu{sub 4} and its reference compounds YAgCu{sub 4} and LuAgCu{sub 4} are interpreted in terms of an enhanced density of states at the Fermi level for the Yb-based compound. The results of susceptibility and ESR (Korringa rate and g-shift) measurements show negligible electron-electron exchange enhancement for all the studied compounds. The exchange interaction between the Gd{sup 3+} local moment and the conduction electrons (c-e) is c-e wave vector dependent in all three compounds. {copyright} {ital 1997} {ital The American Physical Society}

  1. 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

    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.

  2. Cu-doping effect on dielectric properties of organic gel synthesized Ba{sub 4}YMn{sub 3−x}Cu{sub x}O{sub 11.5±δ}

    SciTech Connect

    Barbier, Tristan; Autret-Lambert, Cécile; Andreazza, Pascal; Ruyter, Antoine; Honstettre, Christophe; Lambert, Sébastien; Gervais, François; Lethiecq, Marc

    2013-10-15

    Copper doped-Ba{sub 4}YMn{sub 3−x}Cu{sub x}O{sub 11.5±δ} samples were synthesized by an organic gel assisted citrate process. X-ray diffraction of compositions with x=0.002, 0.005, 0.01, 0.02 and 0.04 does not reveal any change of hexagonal perovskite structure on doping. The effects of Cu-doping on the microstructure and dielectric properties were investigated. Cu doping modifies the electrical properties at the level of the impedance characteristics of both grain and grain boundary and to understand these different behaviours, we have carried out high-resolution transmission electron microscopy analysis. Among the Ba{sub 4}YMn{sub 3−x}Cu{sub x}O{sub 11.5±δ} specimens studied, the composition x=0.002 shows a permittivity (ε′{sub r}) higher than the undoped compound and a lower loss tangent (tanδ) over several orders of magnitude of frequency. - Graphical abstract: Highlighting of many stacking faults (intergrowths) in substituted compounds with x>0.01 (right picture), which could explain the different dielectric properties observed in these compounds. However compounds with x>0.01 remain with a better stacking sequence as we can see on the left picture. Display Omitted - Highlights: • High permittivity of the Ba{sub 4}YMn{sub 3−x}Cu{sub x}O{sub 11.5±δ}. • Substitution leads to a mixed oxidation state for manganese: Mn{sup 4+}/Mn{sup 3+}. • Creation of oxygen vacancies which are responsible for stacking faults. • Highlighting relationship between Cu substitution and dielectric properties.

  3. System size dependence of cluster properties from two-particle angular correlations in Cu+Cu and Au+Au collisions at sq root(s{sub NN})=200 GeV

    SciTech Connect

    Alver, B.; Ballintijn, M.; Busza, W.; Gulbrandsen, K.; Henderson, C.; Kane, J. L.; Kulinich, P.; Li, W.; Loizides, C.; Reed, C.; Roland, C.; Roland, G.; Stephans, G. S. F.; Nieuwenhuizen, G. J. van; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wenger, E.; Wyslouch, B.; Back, B. B.

    2010-02-15

    We present results on two-particle angular correlations in Cu+Cu and Au+Au collisions at a center-of-mass energy per nucleon pair of 200 GeV over a broad range of pseudorapidity (eta) and azimuthal angle (phi) values as a function of collision centrality. The PHOBOS detector at the Relativistic Heavy Ion Collider has a uniquely large angular coverage for inclusive charged particles, which allows for the study of correlations on both long- and short-range scales. A complex two-dimensional correlation structure in {Delta}{eta} and {Delta}{phi} emerges, which is interpreted in the context of a cluster model. The effective cluster size and decay width are extracted from the two-particle pseudorapidity correlation functions. The effective cluster size found in semicentral Cu+Cu and Au+Au collisions is comparable to that found in proton-proton collisions but a nontrivial decrease in size with increasing centrality is observed. Moreover, a comparison of results from Cu+Cu versus Au+Au collisions shows an interesting scaling of the effective cluster size with the measured fraction of total cross section (which is related to the ratio of the impact parameter to the nuclear radius, b/2R), suggesting a geometric origin. Further analysis for pairs from restricted azimuthal regions shows that the effective cluster size at {Delta}{phi}{approx}180 deg. drops more rapidly toward central collisions than the size at {Delta}{phi}{approx}0 deg. The effect of limited {eta} acceptance on the cluster parameters is also addressed, and a correction is applied to present cluster parameters for full {eta} coverage, leading to much larger effective cluster sizes and widths than previously noted in the literature. These results should provide insight into the hot and dense medium created in heavy ion collisions.

  4. Multi-functional ultrathin PdxCu1-x and Pt~PdxCu1-x one-dimensional nanowire motifs for various small molecule oxidation reactions

    SciTech Connect

    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 Pd1–xCux alloys but also Pt-coated Pd1–xCux (i.e., Pt~Pd1–xCux; 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 Pd1–xCux nanowires all exhibit enhanced FAOR activities as compared with not only analogous Pd ultrathin nanowires but also commercial Pt and Pd standards, with Pd9Cu representing the “optimal” composition. Moreover, our group of Pt~Pd1–xCux 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

  5. Measurement of K0S and K*0 in p+p, d+Au, and Cu+Cu collisions at sqrt SNN = 200 GeV

    SciTech Connect

    Adare, A.; Aidala, C.

    2014-11-01

    The PHENIX experiment at the Relativistic Heavy Ion Collider has performed a systematic study of K0S and K*0 meson production at midrapidity in p+p, d+Au, and Cu+Cu collisions at sqrt SNN = 200 GeV. The K0S and K*0 mesons are reconstructed via their K0S and π0(→γγ)π0 (→γγ) and K*0 → K ± π± decay modes, respectively. The measured transverse-momentum spectra are used to determine the nuclear modification factor of K0S and K*0 mesons in d+Au and Cu+Cu collisions at different centralities. In the d+Au collisions, the nuclear modification factor of K0S and K*0 mesons is almost constant as a function of transverse momentum and is consistent with unity showing that cold-nuclear-matter effects do not play a significant role in the measured kinematic range. In Cu+Cu collisions, within the uncertainties no nuclear modification is registered in peripheral collisions. In central collisions, both mesons show suppression relative to the expectations from the p+p yield scaled by the number of binary nucleon-nucleon collisions in the Cu+Cu system. In the pT range 2–5 GeV/c, the strange mesons ( K0S, K*0) similarly to the Φ meson with hidden strangeness, show an intermediate suppression between the more suppressed light quark mesons (π0) and the nonsuppressed baryons (p, p-bar). At higher transverse momentum, pT > 5 GeV/c, production of all particles is similarly suppressed by a factor of ≈2. (auth)

  6. Location of gap nodes in the organic superconductors {kappa}-(ET){sub 2}Cu(NCS){sub 2} and {kappa}-(ET){sub 2}Cu[N(CN){sub 2}Br determined by magnetocalorimetry.

    SciTech Connect

    Malone, L.; Taylor, O. J.; Schlueter, J. A.; Carrington, A.; Materials Science Division; Univ. Bristol

    2010-07-16

    We report specific-heat measurements of the organic superconductors {kappa}-(ET){sub 2}Cu(NCS){sub 2} and {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Br. When the magnetic field is rotated in the highly conducting planes at low temperature (T = 0.4 K), we observe clear oscillations of specific heat which have a strong fourfold component. The observed strong field and temperature dependence of this fourfold component identifies it as originating from nodes in the superconducting energy gap which point along the in-plane crystal axes (d{sub xy} symmetry).

  7. Role of surface states and defects in the ultrafast nonlinear optical properties of CuS quantum dots

    SciTech Connect

    Mary, K. A. Ann; Unnikrishnan, N. V.; Philip, Reji

    2014-07-01

    We report facile preparation of water dispersible CuS quantum dots (2–4 nm) and nanoparticles (5–11 nm) through a nontoxic, green, one-pot synthesis method. Optical and microstructural studies indicate the presence of surface states and defects (dislocations, stacking faults, and twins) in the quantum dots. The smaller crystallite size and quantum dot formation have significant effects on the high energy excitonic and low energy plasmonic absorption bands. Effective two-photon absorption coefficients measured using 100 fs laser pulses employing open-aperture Z-scan in the plasmonic region of 800 nm reveal that CuS quantum dots are better ultrafast optical limiters compared to CuS nanoparticles.

  8. Low voltage tunneling magnetoresistance in CuCrO{sub 2}-based semiconductor heterojunctions at room temperature

    SciTech Connect

    Li, X. R.; Han, M. J.; Shan, C.; Hu, Z. G. Zhu, Z. Q.; Chu, J. H.; Wu, J. D.

    2014-12-14

    CuCrO{sub 2}-based heterojunction diodes with rectifying characteristics have been fabricated by combining p-type Mg-doped CuCrO{sub 2} and n-type Al-doped ZnO. It was found that the current for the heterojunction in low bias voltage region is dominated by the trap-assisted tunneling mechanism. Positive magnetoresistance (MR) effect for the heterojunction can be observed at room temperature due to the tunneling-induced antiparallel spin polarization near the heterostructure interface. The MR effect becomes enhanced with the magnetic field, and shows the maximum at a bias voltage around 0.5 V. The phenomena indicate that the CuCrO{sub 2}-based heterojunction is a promising candidate for low-power semiconductor spintronic devices.

  9. Properties of Cu/sub 2-x/SCdS photocells fabricated by a photoelectrochemical layer deposition method

    SciTech Connect

    Inoue, T.; Yamase, T.

    1986-12-01

    Heterojunction photocell with a <Cu/sub 2-x/SCdS> junction were fabricated by a layer deposition process, resulting from a photoelectrochemical reaction at a CdS electrode surface. The properties of photocells depended on the cell preparation conditions both the sintering of a CdS substrate and the photoformation of Cu/sub 2-x/S. Output power of a photocell was 1.4 mW with Voc = 0.45 V and I/sub sc/ = 6 mA/cm/sup 2/ against the input light irradiation with 34 mW, when a CdS substrate was prepared by sintering at 750/sup 0/C for 3 h and a Cu/sub 2-x/S layer was formed by a photogenerated charge of 40 mC.

  10. 15.4% CuIn1-XGaXSe2-Based Photovoltaic Cells from Solution-Based Precursor Films

    SciTech Connect

    Bhattacharya, R. N.; Batchelor, W.; Contreras, M. A.; Noufi, R. N.; Hiltner, J. F.; Sites, J. R.

    1999-05-25

    We have fabricated 15.4%- and 12.4%-efficient CuIn1-XGaXSe2 (CIGS)-based photovoltaic devices from solution-based electrodeposition (ED) and electroless-deposition (EL) precursors. As-deposited precursors are Cu-rich CIGS. Additional In, Ga, and Se are added to the ED and EL precursor films by physical vapor deposition (PVD) to adjust the final film composition to CuIn1-XGaXSe2. The ED and EL device parameters are compared with those of a recent world record, an 18.8%-efficient PVD device. The tools used for comparison are current voltage, capacitance voltage, and spectral response characteristics.

  11. Synthesis and characterization of CuInS{sub 2} nanostructure by ultrasonic-assisted method and different precursors

    SciTech Connect

    Mousavi-Kamazani, Mehdi; Salavati-Niasari, Masoud; Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167 ; Emadi, Hamid

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► CuInS{sub 2} nanoparticles were synthesized by ultrasonic assisted method. ► CuInS{sub 2} nanoparticles obtained after annealing at 350 °C for 1 h. ► The effect of some parameters including ultrasonic was investigated. -- Abstract: This paper reports on the synthesis of CuInS{sub 2} nanostructure via an ultrasonic assisted method by employing different sulfur source. Morphology, structure and composition of the obtained products were characterized by X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), scanning electron microscope (SEM), infrared (IR) spectrum, and photoluminescence (PL) spectroscopy. The effects of ultrasonic irradiation, power and time of irradiation, surfactant, and type of copper source were investigated.

  12. Film Deposition, Cryogenic RF Testing and Materials Analysis of a Nb/Cu Single Cell SRF Cavity

    SciTech Connect

    Zhao, Xin; Geng, Rongli; Palczerski, Ari; Li, Yongming

    2013-09-01

    In this study, we present preliminary results on using a cathodic-arc-discharge Nb plasma ion source to establish a Nb film-coated single-cell Cu cavity for SRF research. The polycrystalline Cu cavity was fabricated and mirror-surface-finished by a centrifugal barrel polishing (CBP) process at Jefferson Lab. Special pre-coating processes were conducted, in order to create a template-layer for follow-on Nb grain thickening. A sequence of cryogenic RF testing demonstrated that the Nb film does show superconductivity. But the quality factor of this Nb/Cu cavity is low as a result of high residual surface resistance. We are conducting a thorough materials characterization to explore if some microstructural defects or hydrogen impurities, led to such a low quality factor.

  13. Tuned sensitivity towards H{sub 2}S and NH{sub 3} with Cu doped barium strontium titanate materials

    SciTech Connect

    Simion, C. E. Teodorescu, V. S.; Stănoiu, A.; Sackmann, A.; Ruşti, C. F.; Piticescu, R. M.

    2014-11-05

    The different amount of Cu-doped Barium Strontium Titanate (BST) thick film materials have been tested for their gas-sensing performances towards NH{sub 3} and H{sub 2}S under dry and 50% relative humidity (RH) background conditions. The optimum NH{sub 3} sensitivity was attained with 0.1mol% Cu-doped BST whereas the selective detection of H{sub 2}S was highlighted using 5mol% Cu-doped BST material. No cross-sensitivity effects to CO, NO{sub 2}, CH{sub 4} and SO{sub 2} were observed for all tested materials operated at their optimum temperature (200°C) under humid conditions (50% RH). The presence of humidity clearly enhances the gas sensitivity to NH{sub 3} and H{sub 2}S detection.

  14. First-principles study of direct and narrow band gap semiconducting β -CuGaO2

    DOE PAGES [OSTI]

    Nguyen, Manh Cuong; Zhao, Xin; Wang, Cai-Zhuang; Ho, Kai-Ming

    2015-04-16

    Semiconducting oxides have attracted much attention due to their great stability in air or water and the abundance of oxygen. Recent success in synthesizing a metastable phase of CuGaO2 with direct narrow band gap opens up new applications of semiconducting oxides as absorber layer for photovoltaics. Using first-principles density functional theory calculations, we investigate the thermodynamic and mechanical stabilities as well as the structural and electronic properties of the β-CuGaO2 phase. Our calculations show that the β-CuGaO2 structure is dynamically and mechanically stable. The energy band gap is confirmed to be direct at the Γ point of Brillouin zone. Inmore » conclusion, the optical absorption occurs right at the band gap edge and the density of states near the valance band maximum is large, inducing an intense absorption of light as observed in experiment.« less

  15. Effect of filler metal composition on the strength of yttria stabilized zirconia joints brazed with Pd-Ag-CuOx

    SciTech Connect

    Darsell, Jens T.; Weil, K. Scott

    2008-09-08

    The Ag-CuOx system is of interest to be used to be used as an air braze filler metal for joining high temperature electrochemical devices. Previous work has shown that the melting temperatures can be increased by adding palladium to Ag-CuOx and it is expected that this may aid high temperature stability. This work compares the room temperature bend strength of joints made between yttria-stabilized zirconia (YSZ) air brazed using Ag-CuOx without palladium and with 5 and 15mol% palladium additions. It has been found that in general palladium decreases joint strength, especially in low copper oxide compositions filler metals. At high copper oxide contents, brittle fracture through both copper oxide rich phases and the YSZ limits joint strength.

  16. Kinetics of sorption of Cu(II)-ethylenediaminetetraacetic acid chelated anions on cross-linked, polyaminated chitosan beads

    SciTech Connect

    Juang, R.S.; Ju, C.Y.

    1998-08-01

    Rates of sorption of Cu(II)-ethylenediaminetetraacetic acid (EDTA) chelated anions from aqueous solutions on cross-linked, poly(ethylenimine) (PEI)-modified chitosan beads were measured in a batch stirred vessel. All experiments were carried out in an equimolar solution of Cu(II) and EDTA (0.47--3.15 mol/m{sup 3}). It was shown that the rates of sorption increased with an increase in the initial concentration of Cu(II), pH, and temperature but decreased with an increase in the molecular weight of PEI introduced in the beads. The widely used homogeneous diffusion model based on Fick`s law and the shrinking core model cannot describe the sorption process. On the contrary, the kinetic data were well fit by the Elovich equation. The apparent activation energies evaluated (3.5--8.4 kcal/mol at pH 3) indicated the combined film and particle diffusion mechanism.

  17. Effect of electronic structures on catalytic properties of CuNi alloy and Pd in MeOH-related reactions

    SciTech Connect

    Tsai, An-Pang; Kimura, Tomofumi; Suzuki, Yukinori; Kameoka, Satoshi; Shimoda, Masahiko; Ishii, Yasushi

    2013-04-14

    We investigated the catalytic properties of a CuNi solid solution and Pd for methanol-related reactions and associated valence electronic structures. Calculations and X-ray photoelectron spectroscopy measurements revealed that the CuNi alloy has a similar valence electronic structure to Pd and hence they exhibited similar CO selectivities in steam reforming of methanol and decomposition of methanol. Samples prepared by various processes were found to have similar CO selectivities. We conjecture that alloying of Cu and Ni dramatically alters the valence electronic structures, making it similar to that of Pd so that the alloy exhibits similar catalytic properties to Pd. First-principles slab calculations of surface electronic structures support this conjecture.

  18. Enhanced hydrogenation and reduced lattice distortion in size selected Pd-Ag and Pd-Cu alloy nanoparticles

    SciTech Connect

    Sengar, Saurabh K.; Mehta, B. R.; Kulriya, P. K.; Khan, S. A.

    2013-10-21

    Important correlation between valence band spectra and hydrogenation properties in Pd alloy nanoparticles is established by studying the properties of size selected and monocrystalline Pd, Ag, Cu, Pd-Ag, and Pd-Cu nanoparticles. The X-ray photoelectron spectroscopy and elastic recoil detection analysis show that size induced Pd4d centroid shift is related to enhanced hydrogenation with H/Pd ratio of 0.57 and 0.49 in Pd-Ag and Pd-Cu nanoparticles in comparison to reported bulk values of 0.2 and 0.1, respectively. Pd-alloy nanoparticles show lower hydrogen induced lattice distortion. The reduced distortion and higher hydrogen reactivity of Pd-alloy nanoparticles is important for numerous hydrogen related applications.

  19. Role of W and Mn for reliable 1X nanometer-node ultra-large-scale integration Cu interconnects proved by atom probe tomography

    SciTech Connect

    Shima, K.; Shimizu, H.; Momose, T.; Shimogaki, Y.; Tu, Y.; Takamizawa, H.; Shimizu, Y.; Inoue, K.; Nagai, Y.

    2014-09-29

    We used atom probe tomography (APT) to study the use of a Cu(Mn) as a seed layer of Cu, and a Co(W) single-layer as reliable Cu diffusion barriers for future interconnects in ultra-large-scale integration. The use of Co(W) layer enhances adhesion of Cu to prevent electromigration and stress-induced voiding failures. The use of Cu(Mn) as seed layer may enhance the diffusion barrier performance of Co(W) by stuffing the Cu diffusion pass with Mn. APT was used to visualize the distribution of W and Mn in three dimensions with sub-nanometer resolution. W was found to segregate at the grain boundaries of Co, which prevents diffusion of Cu via the grain boundaries. Mn was found to diffuse from the Cu(Mn) layer to Co(W) layer and selectively segregate at the Co(W) grain boundaries with W, reinforcing the barrier properties of Co(W) layer. Hence, a Co(W) barrier coupled with a Cu(Mn) seed layer can form a sufficient diffusion barrier with film that is less than 2.0-nm-thick. The diffusion barrier behavior was preserved following a 1-h annealing at 400 °C. The underlayer of the Cu interconnects requires a large adhesion strength with the Cu, as well as low electrical resistivity. The use of Co(W) has previously been shown to satisfy these requirements, and addition of Mn is not expected to deteriorate these properties.

  20. Modification of carbon nanotubes by CuO-doped NiO nanocomposite for use as an anode material for lithium-ion batteries

    SciTech Connect

    Mustansar Abbas, Syed; Tajammul Hussain, Syed; Ali, Saqib; Ahmad, Nisar; Ali, Nisar; Abbas, Saghir; Ali, Zulfiqar

    2013-06-15

    CuO-doped NiO (CuNiO) with porous hexagonal morphology is fabricated via a modified in-situ co-precipitation method and its nanocomposite is prepared with carbon nanotubes (CNTs). The electrochemical properties of CuNiO/CNT nanocomposite are investigated by cyclic voltammetry (CV), galvanostatic chargedischarge tests and electrochemical impedance spectroscopy (EIS). Since Cu can both act as conductor and a catalyst, the CuNiO/CNT nanocomposite exhibits higher initial coulombic efficiency (82.7% of the 2nd cycle) and better capacity retention (78.6% on 50th cycle) than bare CuNiO (78.9% of the 2nd cycle), CuO/CNT (76.8% of the 2nd cycle) and NiO/CNT (77.7% of the 2nd cycle) at the current density of 100 mA /g. This high capacity and good cycling ability is attributed to the partial substitution of Cu{sup +2} for Ni{sup +2}, resulting in an increase of holes concentration, and therefore improved p-type conductivity along with an intimate interaction with CNTs providing large surface area, excellent conduction, mechanical strength and chemical stability. - Graphical abstract: The porous CuNiO/CNT nanocomposite synthesized via a modified co-precipitation method in combination with subsequent calcination was applied in the negative electrode materials for lithium-ion batteries and exhibited high electrochemical performance. - Highlights: CuO doped NiO/CNTs nano composite is achieved via a simple co-precipitation method. Monodispersity, shape and sizes of sample particles is specifically controlled. Good quality adhesion between CNTs and CuNiO is visible from TEM image. High electrochemical performance is achieved. Discharge capacity of 686 mA h/g after 50 cycles with coulombic efficiency (82.5%)