Sample records for tiny crystals glow

  1. New Family of Tiny Crystals Glow Bright in LED Lights | Advanced...

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

    crystals that glow different colors may be the missing ingredient for white light-emitting diode (LED) lighting that illuminates homes and offices as effectively as natural...

  2. New family of tiny crystals glow bright in LED lights | ornl.gov

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated CodesTransparencyDOE Project Taps HPCNew User and DataNew companiesNewNew

  3. Learning Tiny Theories Tim Menzies

    E-Print Network [OSTI]

    Menzies, Tim

    Learning Tiny Theories Tim Menzies , Rajesh Gunnalan , Kalaivani Appukutty , Amarnath Srinivasan Engineering, University of British Columbia, Canada {gunnalan|avani|amarnath}@csee

  4. Glowing Bacteria: Transformation Efficiency

    E-Print Network [OSTI]

    Rose, Michael R.

    1 Glowing Bacteria: Transformation Efficiency Purpose: To determine how well your E. coli cells took up and expressed GFP after transformation. Background: Transformation efficiency is a quantitative)______ (Fraction of DNA spread on plate) = ______ µg plasmid DNA spread on plate #12;2 5. Transformation efficiency

  5. PERIODIC GLOW DISCHARGE REPORT

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)IntegratedSpeeding access toTest andOptimize832 2.860SelectedGLOW DISCHARGE REPORT

  6. Powerful glow discharge excilamp

    DOE Patents [OSTI]

    Tarasenko, Victor F. (Tomsk, RU); Panchenko, Aleksey N. (Tomsk, RU); Skakun, Victor S. (Tomsk, RU); Sosnin, Edward A. (Tomsk, RU); Wang, Francis T. (Danville, CA); Myers, Booth R. (Livermore, CA); Adamson, Martyn G. (Danville, CA)

    2002-01-01T23:59:59.000Z

    A powerful glow discharge lamp comprising two coaxial tubes, the outer tube being optically transparent, with a cathode and anode placed at opposite ends of the tubes, the space between the tubes being filled with working gas. The electrodes are made as cylindrical tumblers placed in line to one other in such a way that one end of the cathode is inserted into the inner tube, one end of the anode coaxially covers the end of the outer tube, the inner tube penetrating and extending through the anode. The increased electrodes' surface area increases glow discharge electron current and, correspondingly, average radiation power of discharge plasma. The inner tube contains at least one cooling liquid tube placed along the axis of the inner tube along the entire lamp length to provide cathode cooling. The anode has a circumferential heat extracting radiator which removes heat from the anode. The invention is related to lighting engineering and can be applied for realization of photostimulated processes under the action of powerful radiation in required spectral range.

  7. Ordered dust structures in a glow discharge

    SciTech Connect (OSTI)

    Karasev, V. Yu., E-mail: plasmadust@yandex.ru; Ivanov, A. Yu.; Dzlieva, E. S.; Eikhval'd, A. I. [St. Petersburg State University, Institute of Physics (Russian Federation)

    2008-02-15T23:59:59.000Z

    Highly ordered three-dimensional dust structures are created in a striated glow discharge, and their horizontal cross-sectional images are analyzed. Calculated correlation functions, local correlation parameters, and corresponding approximations are used to classify the state of a structure according to the Kosterlitz-Thouless-Halperin-Nelson-Young (KTHNY) two-dimensional melting theory and a phenomenological approach. An orientational map based on an orientational parameter is proposed to expose domains in a cross section of a structure. It is shown that a plasma crystal is a polycrystal consisting of hexagonal domains (crystallites). Thermophoretic forces are used to create corners of various angles in the perimeter of the structure. Transition between hexagonal and square cell shapes is observed.

  8. Tiny Glass Bubbles With Big Potential

    Broader source: Energy.gov [DOE]

    If these glass microspheres' walls could talk…They would explain how their tiny pores allow the potential for handling, storing and transporting a variety of materials, including drugs that have...

  9. Constricted glow discharge plasma source

    DOE Patents [OSTI]

    Anders, Andre (Albany, CA); Anders, Simone (Albany, CA); Dickinson, Michael (San Leandro, CA); Rubin, Michael (Berkeley, CA); Newman, Nathan (Winnetka, IL)

    2000-01-01T23:59:59.000Z

    A constricted glow discharge chamber and method are disclosed. The polarity and geometry of the constricted glow discharge plasma source is set so that the contamination and energy of the ions discharged from the source are minimized. The several sources can be mounted in parallel and in series to provide a sustained ultra low source of ions in a plasma with contamination below practical detection limits. The source is suitable for applying films of nitrides such as gallium nitride and oxides such as tungsten oxide and for enriching other substances in material surfaces such as oxygen and water vapor, which are difficult process as plasma in any known devices and methods. The source can also be used to assist the deposition of films such as metal films by providing low-energy ions such as argon ions.

  10. Glow Plug Integrated Piezo-Ceramic Combustion Sensor for Diesel...

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

    Glow Plug Integrated Piezo-Ceramic Combustion Sensor for Diesel Engines Glow Plug Integrated Piezo-Ceramic Combustion Sensor for Diesel Engines 2005 Diesel Engine Emissions...

  11. Atmospheric sampling glow discharge ionization source

    DOE Patents [OSTI]

    McLuckey, S.A.; Glish, G.L.

    1989-07-18T23:59:59.000Z

    An atmospheric sampling glow discharge ionization source that can be used in combination with an analytical instrument which operates at high vacuum, such as a mass spectrometer. The atmospheric sampling glow discharge ionization source comprises a chamber with at least one pair of electrodes disposed therein, an inlet for a gaseous sample to be analyzed and an outlet communicating with an analyzer which operates at subatmospheric pressure. The ionization chamber is maintained at a pressure below atmospheric pressure, and a voltage difference is applied across the electrodes to induce a glow discharge between the electrodes, so that molecules passing through the inlet are ionized by the glow discharge and directed into the analyzer. The ionization source accepts the sample under atmospheric pressure conditions and processes it directly into the high vacuum instrument, bridging the pressure gap and drawing off unwanted atmospheric gases. The invention also includes a method for analyzing a gaseous sample using the glow discharge ionization source described above. 3 figs.

  12. Glow-discharge synthesis of silicon nitride precursor powders

    SciTech Connect (OSTI)

    Ho, P.; Buss, R.J.; Loehman, R.E. (Sandia National Laboratories, Albuquerque, New Mexico 87185-5800 (US))

    1989-07-01T23:59:59.000Z

    A radio-frequency glow discharge is used for the synthesis of submicron, amorphous, silicon nitride precursor powders from silane and ammonia. Powders are produced with a range of Si/N ratios, including stoichiometric, Si-rich, and N-rich, and contain substantial amounts of hydrogen. The powders appear to be similar to silicon diimide and are easily converted to oxide by water vapor. The powders lose weight and crystallize to a mixture of {alpha} and {beta}-Si{sub 3}N{sub 4} after prolonged heating at 1600{degree}C. Studies of spectrally and spatially resolved optical emission from the plasma are reported.

  13. Tiny Bubbles in my BEC

    SciTech Connect (OSTI)

    Blinova, Alina A. [Los Alamos National Laboratory

    2012-08-01T23:59:59.000Z

    Ultracold atomic gases provide a unique way for exploring many-body quantum phenomena that are inaccessible to conventional low-temperature experiments. Nearly two decades ago the Bose-Einstein condensate (BEC) - an ultracold gas of bosons in which almost all bosons occupy the same single-particle state - became experimentally feasible. Because a BEC exhibits superfluid properties, it can provide insights into the behavior of low-temperature helium liquids. We describe the case of a single distinguishable atom (an impurity) embedded in a BEC and strongly coupled to the BEC bosons. Depending on the strength of impurity-boson and boson-boson interactions, the impurity self-localizes into two fundamentally distinct regimes. The impurity atom can behave as a tightly localized 'polaron,' akin to an electron in a dielectric crystal, or as a 'bubble,' an analog to an electron bubble in superfluid helium. We obtain the ground state wavefunctions of the impurity and BEC by numerically solving the two coupled Gross-Pitaevskii equations that characterize the system. We employ the methods of imaginary time propagation and conjugate gradient descent. By appropriately varying the impurity-boson and boson-boson interaction strengths, we focus on the polaron to bubble crossover. Our results confirm analytical predictions for the polaron limit and uncover properties of the bubble regime. With these results we characterize the polaron to bubble crossover. We also summarize our findings in a phase diagram of the BEC-impurity system, which can be used as a guide in future experiments.

  14. Glow discharge plasma deposition of thin films

    DOE Patents [OSTI]

    Weakliem, Herbert A. (Pennington, NJ); Vossen, Jr., John L. (Bridgewater, NJ)

    1984-05-29T23:59:59.000Z

    A glow discharge plasma reactor for deposition of thin films from a reactive RF glow discharge is provided with a screen positioned between the walls of the chamber and the cathode to confine the glow discharge region to within the region defined by the screen and the cathode. A substrate for receiving deposition material from a reactive gas is positioned outside the screened region. The screen is electrically connected to the system ground to thereby serve as the anode of the system. The energy of the reactive gas species is reduced as they diffuse through the screen to the substrate. Reactive gas is conducted directly into the glow discharge region through a centrally positioned distribution head to reduce contamination effects otherwise caused by secondary reaction products and impurities deposited on the reactor walls.

  15. Probiotic Bacteria Induce a ‘Glow of Health’

    E-Print Network [OSTI]

    Levkovich, Tatiana

    Radiant skin and hair are universally recognized as indications of good health. However, this ‘glow of health’ display remains poorly understood. We found that feeding of probiotic bacteria to aged mice induced integumentary ...

  16. Tiny HI Clouds in the Local ISM

    E-Print Network [OSTI]

    Robert Braun; Nissim Kanekar

    2005-06-08T23:59:59.000Z

    We report deep, high spectral resolution WSRT HI 21cm observations of four high latitude compact radio sources, that have revealed a new population of tiny, discrete clouds in the diffuse ISM, with peak optical depths tau ~ 0.1-2%, HI column densities of 0.4-8 * 10^{18} cm^{-2} and core temperatures of 20-80 K. Imaging detections confirm these low column densities and imply linear core dimensions of a few thousand AU, assuming a distance of 100 pc. The physical origin of these tiny HI structures and their distribution in the ISM is at present unknown. Further observations will be required to determine whether they are a ubiquitous component of the ISM.

  17. Tiny HI Clouds in the Local ISM

    E-Print Network [OSTI]

    Robert Braun; Nissim Kanekar

    2004-09-17T23:59:59.000Z

    Very sensitive HI absorption spectra (tau RMS about 10^-4 over 1 km/s) toward high latitude QSOs have revealed a population of tiny discrete features in the diffuse ISM with peak tau of 0.1 - 2% and core line-widths corresponding to temperatures as low as 20 K. Imaging detections confirm linear dimensions of a few 1000 AU. We suggest these structures may be formed by the stellar winds of intermediate mass stars. A more speculative origin might involve molecular "dark matter".

  18. A New Family of Quasicrystals | Advanced Photon Source

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

    Understanding of Superconductivity New Family of Tiny Crystals Glow Bright in LED Lights How Serotonin Receptors Can Shape Drug Effects, from LSD to Migraine Medication X-rays...

  19. Cool Muscles: Storing Elastic Energy for Flight | Advanced Photon...

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

    Understanding of Superconductivity New Family of Tiny Crystals Glow Bright in LED Lights How Serotonin Receptors Can Shape Drug Effects, from LSD to Migraine Medication X-rays...

  20. Molten Metal Solidifies into a New Kind of Glass | Advanced Photon...

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

    Understanding of Superconductivity New Family of Tiny Crystals Glow Bright in LED Lights Science Highlights Archives: 2014 2013 | 2012 | 2011 | 2010 2009 | 2008 | 2007 | 2006...

  1. Big energy savings in a tiny package

    SciTech Connect (OSTI)

    Chambers, A.

    1995-02-01T23:59:59.000Z

    PNL is developing microscale technologies to revolutionize energy use in homes, businesses and industry. One project is a miniature heat pump that is smaller than a dime. The pumps would be so small that hundreds or thousands could be manufactured in sheets, which could then be incorporated into the walls of buildings to replace conventional heat pumps, furnaces, air conditioners and ductwork. The tiny heat pumps could save much of the energy loss associated with conventional heatpump technology because of the elimination of the ductwork needed to carry air throughout the house. Like conventional heat pumps, micro heat pumps have an evaporator, a condenser and a compressor. PNL has developed a micro heat exchanger that serves as a condenser and evaporator. The heat exchangers are made with the same photo etching process used to make computer chips. Tiny channels are etched into a dime-sized piece of metal. Refrigerant flows through these channels and evaporates or condenses, and the heat is transferred to the outside.

  2. Tackling Big Challenges Using Tiny Crystals | Stanford Synchrotron...

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

    Conference Room 108A Speaker: Matteo Cargnello, Stanford Univeristy Program Description Fossil fuels are not endless and their extensive use is causing irreversible climate...

  3. abnormal glow discharge: Topics by E-print Network

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

    29 Glow Discharge Enhanced Chemical Reaction: Application in Ammonia Synthesis and Hydrocarbon Gas Cleanup Texas A&M University - TxSpace Summary: ......

  4. atmospheric glow discharge: Topics by E-print Network

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

    34 Glow Discharge Enhanced Chemical Reaction: Application in Ammonia Synthesis and Hydrocarbon Gas Cleanup Texas A&M University - TxSpace Summary: ......

  5. ablation glow discharge: Topics by E-print Network

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

    29 Glow Discharge Enhanced Chemical Reaction: Application in Ammonia Synthesis and Hydrocarbon Gas Cleanup Texas A&M University - TxSpace Summary: ......

  6. analytical glow discharge: Topics by E-print Network

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

    29 Glow Discharge Enhanced Chemical Reaction: Application in Ammonia Synthesis and Hydrocarbon Gas Cleanup Texas A&M University - TxSpace Summary: ......

  7. TiNi shape memory alloy thin films for microactuator application

    E-Print Network [OSTI]

    Fu, Yongqing

    TiNi films were prepared by co-sputtering TiNi target and a separate Ti target. Crystalline structure and phase transformation behaviors of TiNi films were investigated. Results showed that TiNi films had fine grain size ...

  8. Phenomena of oscillations in atmospheric pressure direct current glow discharges

    SciTech Connect (OSTI)

    Liu, Fu-cheng [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)] [College of Physics Science and Technology, Hebei University, Baoding 071002 (China); Yan, Wen; Wang, De-zhen [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)] [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2013-12-15T23:59:59.000Z

    Self-sustained oscillations in a dc glow discharge with a semiconductor layer at atmospheric pressure were investigated by means of a one-dimensional fluid model. It is found that the dc glow discharge initially becomes unstable in the subnormal glow region and gives rise to oscillations of plasma parameters. A variety of oscillations with one or more frequencies have been observed under different conditions. The discharge oscillates between the glow discharge mode and the Townsend discharge mode in the oscillations with large amplitude while operates in the subnormal glow discharge mode all the while in the oscillations with small amplitude. Fourier Transform spectra of oscillations reveal the transition mechanism between different oscillations. The effects of semiconductor conductivity on the oscillation frequency of the dominant mode, gas voltage, as well as the discharge current have also been analyzed.

  9. Glow discharge based device for solving mazes

    SciTech Connect (OSTI)

    Dubinov, Alexander E., E-mail: dubinov-ae@yandex.ru; Mironenko, Maxim S.; Selemir, Victor D. [Russian Federal Nuclear Center ? All-Russian Scientific and Research Institute of Experimental Physics (RFNC-VNIIEF), Sarov, Nizhni Novgorod region 607188 (Russian Federation); Sarov Institute of Physics and Technology (SarFTI) of National Research Nuclear University “MEPhI,” Sarov, Nizhni Novgorod region 607188 (Russian Federation); Maksimov, Artem N.; Pylayev, Nikolay A. [Russian Federal Nuclear Center ? All-Russian Scientific and Research Institute of Experimental Physics (RFNC-VNIIEF), Sarov, Nizhni Novgorod region 607188 (Russian Federation)

    2014-09-15T23:59:59.000Z

    A glow discharge based device for solving mazes has been designed and tested. The device consists of a gas discharge chamber and maze-transformer of radial-azimuth type. It allows changing of the maze pattern in a short period of time (within several minutes). The device has been tested with low pressure air. Once switched on, a glow discharge has been shown to find the shortest way through the maze from the very first attempt, even if there is a section with potential barrier for electrons on the way. It has been found that ionization waves (striations) can be excited in the maze along the length of the plasma channel. The dependancy of discharge voltage on the length of the optimal path through the maze has been measured. A reduction in discharge voltage with one or two potential barriers present has been found and explained. The dependency of the magnitude of discharge ignition voltage on the length of the optimal path through the maze has been measured. The reduction of the ignition voltage with the presence of one or two potential barriers has been observed and explained.

  10. Entrainment by Spatiotemporal Chaos in Glow Discharge-Semiconductor Systems

    E-Print Network [OSTI]

    Marat Akhmet; Ismail Rafatov; Mehmet Onur Fen

    2014-06-15T23:59:59.000Z

    Entrainment of limit cycles by chaos [1] is discovered numerically through specially designed unidirectional coupling of two glow discharge-semiconductor systems. By utilizing the auxiliary system approach [2], it is verified that the phenomenon is not a chaos synchronization. Simulations demonstrate various aspects of the chaos appearance in both drive and response systems. Chaotic control is through the external circuit equation and governs the electrical potential on the boundary. The expandability of the theory to collectives of glow discharge systems is discussed, and this increases the potential of applications of the results. Moreover, the research completes the previous discussion of the chaos appearance in a glow discharge-semiconductor system [3].

  11. Nexus Energy Center Raises Funds for Energy-Saving Tiny Home...

    Energy Savers [EERE]

    Raises Funds for Energy-Saving Tiny Home Nexus Energy Center Raises Funds for Energy-Saving Tiny Home bbrnstoriesnexusenergy9-2-14.png Nexus Energy Center, a Huntsville,...

  12. awa-muatan pijar glow: Topics by E-print Network

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

    examined through the so called thermoluminescent Glow Curve, evidences chaotic and fractal regimes. Phase space reconstruction, Correlation Dimension, largest Lyapunov...

  13. Photo of the Week: Tiny Batteries | Department of Energy

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122Commercial602 1,39732onMakeEducationRemediationDepartment ofTiny Batteries Photo of

  14. HoustonChronicle.com -Tiny honor a big deal for algae scientist HoustonChronicle.

    E-Print Network [OSTI]

    Jeong, Hae Jin

    HoustonChronicle.com - Tiny honor a big deal for algae scientist HoustonChronicle. com Section-mail this story June 18, 2005, 5:48PM Tiny honor a big deal for algae scientist By DAVID A. FAHRENTHOLD Washington Post Sometimes, algae can be the highest form of flattery. ADVERTISEMENTSo it was for Diane K. Stoecker

  15. Sensitive glow discharge ion source for aerosol and gas analysis

    DOE Patents [OSTI]

    Reilly, Peter T. A. (Knoxville, TN)

    2007-08-14T23:59:59.000Z

    A high sensitivity glow discharge ion source system for analyzing particles includes an aerodynamic lens having a plurality of constrictions for receiving an aerosol including at least one analyte particle in a carrier gas and focusing the analyte particles into a collimated particle beam. A separator separates the carrier gas from the analyte particle beam, wherein the analyte particle beam or vapors derived from the analyte particle beam are selectively transmitted out of from the separator. A glow discharge ionization source includes a discharge chamber having an entrance orifice for receiving the analyte particle beam or analyte vapors, and a target electrode and discharge electrode therein. An electric field applied between the target electrode and discharge electrode generates an analyte ion stream from the analyte vapors, which is directed out of the discharge chamber through an exit orifice, such as to a mass spectrometer. High analyte sensitivity is obtained by pumping the discharge chamber exclusively through the exit orifice and the entrance orifice.

  16. The Use of DC Glow Discharges as Undergraduate Educational Tools

    SciTech Connect (OSTI)

    Stephanie A. Wissel and Andrew Zwicker, Jerry Ross, and Sophia Gershman

    2012-10-09T23:59:59.000Z

    Plasmas have a beguiling way of getting students excited and interested in physics. We argue that plasmas can and should be incorporated into the undergraduate curriculum as both demonstrations and advanced investigations of electromagnetism and quantum effects. Our device, based on a direct current (DC) glow discharge tube, allows for a number of experiments into topics such as electrical breakdown, spectroscopy, magnetism, and electron temperature.

  17. Minireview: A Tiny Touch: Activation of Cell Signaling Pathways with Magnetic Nanoparticles

    E-Print Network [OSTI]

    Sniadecki, Nathan J.

    98195 Magnetic nanoparticles can be coated with specific ligands that enable them to bind to receptorsMinireview: A Tiny Touch: Activation of Cell Signaling Pathways with Magnetic Nanoparticles Nathan

  18. Tiny Terminators: New Micro-Robots Assemble, Repair Themselves and Are Surprisingly Strong

    Broader source: Energy.gov [DOE]

    Tiny robots that can assemble and repair themselves? Watch a video of Argonne National Laboratory's micro-robots that easily perform tasks that can challenge other robots, including moving objects that are larger than themselves.

  19. LANL Transfers Glowing Bio Technology to Sandia Biotech

    ScienceCinema (OSTI)

    Rorick, Kevin

    2012-08-02T23:59:59.000Z

    Partnering with Los Alamos National Laboratory, an Albuquerque-based company is seeking to transform the way protein and peptide analysis is conducted around the world. Sandia Biotech is using a biological technology licensed from Los Alamos called split green fluorescent protein (sGFP), as a detecting and tracking tool for the protein and peptide industry, valuable in the fields of Alzheimer's research, drug development and other biotechnology fields using protein folding to understand protein expression and mechanisms of action. http://www.lanl.gov/news/stories/glowing-future-for-los-alamos-and-sandia-b iotech-partnership.html

  20. LANL Transfers Glowing Bio Technology to Sandia Biotech

    SciTech Connect (OSTI)

    Rorick, Kevin

    2012-01-01T23:59:59.000Z

    Partnering with Los Alamos National Laboratory, an Albuquerque-based company is seeking to transform the way protein and peptide analysis is conducted around the world. Sandia Biotech is using a biological technology licensed from Los Alamos called split green fluorescent protein (sGFP), as a detecting and tracking tool for the protein and peptide industry, valuable in the fields of Alzheimer's research, drug development and other biotechnology fields using protein folding to understand protein expression and mechanisms of action. http://www.lanl.gov/news/stories/glowing-future-for-los-alamos-and-sandia-b iotech-partnership.html

  1. Modes in a pulse-modulated radio-frequency dielectric-barrier glow discharge

    SciTech Connect (OSTI)

    Shi, J. J.; Zhang, J.; Qiu, G. [College of Science, Donghua University, Shanghai 201620 (China); Walsh, J. L.; Kong, M. G. [Department of Electronic and Electrical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom)

    2008-07-28T23:59:59.000Z

    This letter reports an experimental study of a pulse-modulated radio-frequency dielectric-barrier discharge in atmospheric helium. By controlling the duty cycle at a modulation frequency of 10 and 100 kHz, the 13.56 MHz discharge is shown to operate in three different glow modes: the continuum mode, the discrete mode, and the transition mode. By investigating plasma ignition, residual electrons during power off are found to affect different glow modes. Duty cycle dependences of power density, gas temperature, optical emission intensities at 706 and 777 nm are used to capture clearly the characteristics of the three glow modes.

  2. Trace elements in coal by glow discharge mass spectrometry

    SciTech Connect (OSTI)

    Jacobs, M.L.; Wilson, C.R.; Pestovich, J. Jr. [WAL Inc., Wheat Ridge, CO (United States)] [and others

    1995-08-01T23:59:59.000Z

    A need and a demand exist for determining trace elements in coal and coal related by-products, especially those elements which may potentially be a health hazard. The provisions of the 1990 clean air act require that the EPA evaluate the emissions of electric utilities for trace elements and other potentially hazardous organic compounds. The coal fired electric utility industry supplies roughly 60% of the total generating capacity of 2,882,525 million kilowatt hours (nearly 3 trillion kilowatt hours) generated in the U.S. This is accomplished by 414 power plants scattered across the country that burned 813,508,000 short tons of coal in 1993. The relative volatility of some inorganic constituents in coal makes them more prone to be emitted to the atmosphere following combustion. The production of analytical data for trace elements is known to be a difficult task in coal and by-products of coal combustion (fly ash, bottom ash, gas streams, etc.), in terms of both sample collection and analytical determinations. There are several common analytical methods available to the analyst to determine trace elements in coal and coal by-products. In general analytical germs, the material to be analyzed can be totally solubilized (or extracted), or the elements analytes can be determined in the material as a solid. A relatively new elemental technique, Glow Discharge Mass Spectrometry (GDMS) can be used with solids as well. This new analytical technique had never before been applied directly to coal. The radio frequency-glow discharge quadropole mass spectrometer was used to analyze coal directly for the first time ever by rf-GDMS. The rf-GDMS technique is described.

  3. Dynamics of multiple double layers in high pressure glow discharge in a simple torus

    SciTech Connect (OSTI)

    Kumar Paul, Manash, E-mail: manashkr@gmail.com [Department of Physics, National Institute of Technology Agartala, Tripura–799 046 (India); Sharma, P. K.; Thakur, A.; Kulkarni, S. V.; Bora, D. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat–382 428 (India)

    2014-06-15T23:59:59.000Z

    Parametric characterization of multiple double layers is done during high pressure glow discharge in a toroidal vessel of small aspect ratio. Although glow discharge (without magnetic field) is known to be independent of device geometry, but the toroidal boundary conditions are conducive to plasma growth and eventually the plasma occupy the toroidal volume partially. At higher anode potential, the visibly glowing spots on the body of spatially extended anode transform into multiple intensely luminous spherical plasma blob structures attached to the tip of the positive electrode. Dynamics of multiple double layers are observed in argon glow discharge plasma in presence of toroidal magnetic field. The radial profiles of plasma parameters measured at various toroidal locations show signatures of double layer formation in our system. Parametric dependence of double layer dynamics in presence of toroidal magnetic field is presented here.

  4. Binary and ternary gas mixtures for use in glow discharge closing switches

    DOE Patents [OSTI]

    Hunter, Scott R. (Oak Ridge, TN); Christophorou, Loucas G. (Oak Ridge, TN)

    1990-01-01T23:59:59.000Z

    Highly efficient binary and ternary gas mixtures for use in diffuse glow discharge closing switches are disclosed. The binary mixtures are combinations of helium or neon and selected perfluorides. The ternary mixtures are combinations of helium, neon, or argon, a selected perfluoride, and a small amount of gas that exhibits enhanced ionization characteristics. These mixtures are shown to be the optimum choices for use in diffuse glow discharge closing switches by virtue of the combined physio-electric properties of the mixture components.

  5. TOSSIM: Accurate and Scalable Simulation of Entire TinyOS Applications

    E-Print Network [OSTI]

    historically been a key enabling factor for systems research. We present TOSSIM, a simulator for Tiny; D.2.5 [Software Engineering]: Test- ing and Debugging General Terms Measurement, Experimentation that are difficult to physically construct, and observe interactions that are difficult to capture in a live system

  6. TinyVM: An Energy-Efficient Execution Infrastructure for Sensor Networks

    E-Print Network [OSTI]

    Burgstaller, Bernd

    TinyVM: An Energy-Efficient Execution Infrastructure for Sensor Networks Technical Report CS@cs.yonsei.ac.kr scholz@it.usyd.edu.au ABSTRACT Energy-efficient implementation techniques for virtual machines (VMs) have that bytecode interpretation is affordable for sensor networks if we synthesize VMs specifically for energy-efficiency

  7. CoAP for the Web of Things: From Tiny Resource-constrained

    E-Print Network [OSTI]

    scratch following the REST architectural style. Thus, its features are tailored for Internet of Things (Io-power devices and the Web of Things, as HTTP over TCP is not feasible in these environments. RESTful project, we extended the JavaScript language with an API for direct interaction with tiny IoT devices [9

  8. A MODULAR STEADY STATE GLOW DISCHARGE QUADRUPOLE MASS SPECTROMETER SYSTEM FOR THE AT-LINE ANALYSIS OF PLUTONIUM METAL

    SciTech Connect (OSTI)

    R. STEINER; D. WAYNE

    1998-12-01T23:59:59.000Z

    Historically, glow discharge mass and optical spectrometric techniques have been used in industry for the characterization of processed metals, such as steels and other alloys. This technique is especially well suited for this type of product analysis because the glow discharge ionization source accommodates solid conducting samples with minimal or no sample preparation. This characteristic along with minimal matrix effect considerations makes the glow discharge source well suited for these types of applications.

  9. Ambient-atmosphere glow discharge for determination of elemental concentration in solutions in a high-throughput or transient fashion

    DOE Patents [OSTI]

    Webb, Michael R. (Somerville, MA); Hieftje, Gary M. (Bloomington, IN); Andrade, Francisco (Leeds, GB)

    2011-04-19T23:59:59.000Z

    An ambient atmosphere glow discharge spectrometer is disclosed having a capillary, two electrodes and a means for recording the atomic emissions.

  10. Mechanism behind self-sustained oscillations in direct current glow discharges and in dusty plasmas

    E-Print Network [OSTI]

    Cho, Sung Nae

    2013-01-01T23:59:59.000Z

    An alternative explanation to the mechanism behind self-sustained oscillations of ions in direct current (DC) glow discharges is provided. Such description is distinguished from the one provided by fluid models, where oscillations are attributed to positive feedback mechanism associated with photoionization of particles and photoemission of electrons from the cathode. Here, oscillations arise as consequence of interaction between an ion and surface charges induced by it at the bounding electrodes. Such mechanism provides an elegant explanation to why self-sustained oscillations occur only in the negative resistance region of the voltage-current characteristic curve in DC glow discharges. It is found that oscillation frequencies increase with ion's surface charge density, but at the rate which is significantly slower than it does with electric field. The presented mechanism also describes the self-sustained oscillations of ions in dusty plasmas, demonstrating that oscillations in dusty plasmas and DC glow disc...

  11. Long range temporal correlation in the chaotic oscillations of a dc glow discharge plasma

    SciTech Connect (OSTI)

    Lahiri, S. [Dinabandhu Mahavidyalaya, Bongaon, North 24 Parganas, Kolkata 743235 (India); Roychowdhury, D. [Techno India, EM4/1 Sector V, Salt Lake, Kolkata 700091 (India); Sekar Iyengar, A. N. [Plasma Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India)

    2012-08-15T23:59:59.000Z

    Long range temporal correlations in the fluctuations of the plasma floating potentials (measured using a Langmuir probe) are investigated in a dc glow discharge plasma. Keeping the neutral pressure constant, the discharge voltage was varied and at the formation of the plasma, quasi periodic oscillations were excited and on further increase of the discharge voltage they became chaotic (irregular) beyond a threshold voltage. We compared the Lyapunov exponent with the Hurst exponent obtained from R/S statistics which showed an opposite behaviour at the transition point. These results are perhaps new since we have not come across such comparative analysis for chaotic oscillations in a glow discharge plasma before.

  12. Dynamics of an excitable glow-discharge plasma under external forcing

    SciTech Connect (OSTI)

    Nurujjaman, Md.; Iyengar, A. N. Sekar [Centre for Applicable Mathematics, Tata Institute of Fundamental Research, Sharada Nagar, Chikkabommasandra, Bangalore 560065 (India) and Plasma Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India); Plasma Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India)

    2010-11-15T23:59:59.000Z

    Glow discharge plasma in the excitable regime shows rich dynamical behavior under external forcing. By perturbing the plasma with a subthreshold sawtooth periodic signal, we obtained small subthreshold oscillations that showed resonance with the perturbation frequency. The resonance phenomenon can be useful to estimate characteristic of an excitable system. However, for suprathreshold perturbation, frequency entrainment was observed. In this case, the system showed harmonic frequency entrainment for the perturbation frequencies greater than the characteristic frequency of the system and the excitable behavior for the perturbation frequencies well below the characteristic frequency. The experiments were performed in a glow-discharge plasma where excitability was achieved at a suitable discharge voltage and gas pressure.

  13. Binary and ternary gas mixtures for use in glow discharge closing switches

    DOE Patents [OSTI]

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

    1988-04-27T23:59:59.000Z

    Highly efficient binary and ternary gas mixtures for use in diffuse glow discharge closing switches are disclosed. The binary mixtures are combinations of helium or neon and selected perfluorides. The ternary mixtures are combinations of helium, neon, or argon, a selected perfluoride, and a small amount of gas that exhibits enhanced ionization characteristics. These mixtures are shown to be the optimum choices for use in diffuse glow discharge closing switches by virtue if the combines physio-electric properties of the mixture components. 9 figs.

  14. Parametric investigation of nonlinear fluctuations in a dc glow discharge plasma

    SciTech Connect (OSTI)

    Nurujjaman, Md.; Narayanan, Ramesh; Sekar Iyengar, A. N. [Plasma Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata, 700064 (India)

    2007-12-15T23:59:59.000Z

    Glow discharge plasmas exhibit various types of self-excited oscillations for different initial conditions like discharge voltages and filling pressures. The behavior of such oscillations associated with the anode glow has been investigated using nonlinear techniques like correlation dimension, largest Lyapunov exponent, etc. It is seen that these oscillations go to an ordered state from a chaotic state with an increase in input energy, i.e., with discharge voltages implying occurrence of inverse bifurcations. These results are different from the other observations wherein the fluctuations have been observed to go from ordered to chaotic state.

  15. Ocean Viruses: Tiny entities with Global Impacts ( JGI Seventh Annual User Meeting 2012: Genomics of Energy and Environment)

    ScienceCinema (OSTI)

    Sullivan, Matthew B [University of Arizona

    2013-01-15T23:59:59.000Z

    Matt Sullivan from the University of Arizona on "Ocean Viruses: Tiny Entities with Global Impacts" at the 7th Annual Genomics of Energy & Environment Meeting on March 22, 2012 in Walnut Creek, Calif.

  16. Ocean Viruses: Tiny entities with Global Impacts ( JGI Seventh Annual User Meeting 2012: Genomics of Energy and Environment)

    SciTech Connect (OSTI)

    Sullivan, Matthew B [University of Arizona] [University of Arizona

    2012-03-22T23:59:59.000Z

    Matt Sullivan from the University of Arizona on "Ocean Viruses: Tiny Entities with Global Impacts" at the 7th Annual Genomics of Energy & Environment Meeting on March 22, 2012 in Walnut Creek, Calif.

  17. Poster Abstract: An Open-Source IEEE 802.15.4 MAC Implementation for TinyOS 2.1

    E-Print Network [OSTI]

    Wichmann, Felix

    of the 2.1 release of the TinyOS operating system [6]. Our design is based on three goals: Fig. 1. IEEE 802 published as a part of the 2.1 release of the TinyOS operating system. I. INTRODUCTION The IEEE 802.15.4 standard [1] covers the physical layer (PHY) and the medium access control sublayer (MAC) in the ISO

  18. Role of trace impurities in large-volume noble gas atmospheric-pressure glow discharges

    E-Print Network [OSTI]

    Raja, Laxminarayan L.

    Role of trace impurities in large-volume noble gas atmospheric-pressure glow discharges Xiaohui. Large-volume APG discharges find numerous applications in processing of material surfaces,1 ozone-purity helium is presented, and the role of trace impurities in such noble gas plasmas is established. Trace

  19. The powerful high-voltage glow discharge electron gun and power unit on its base

    SciTech Connect (OSTI)

    Chernov, V.A. [All-Russian Electrotechnical Institute, Moscow (Russian Federation)

    1994-12-31T23:59:59.000Z

    The technical and operational characteristics and features of powerful electron gun with cold cathodes on the basis of high-voltage glow discharge (HGD) are submitted. The systems, ensuring their work are described. Some results of operation and applications of these non-traditional electron guns are presented.

  20. High explosives vapor detection by atmospheric sampling glow discharge ionization/tandem mass spectrometry

    SciTech Connect (OSTI)

    McLuckey, S.A.; Goeringer, D.E.; Asano, K.G. [Oak Ridge National Lab., TN (United States). Chemical and Analytical Sciences Div.

    1996-02-01T23:59:59.000Z

    The combination of atmospheric sampling glow discharge ionization with tandem mass spectrometry for the detection of traces of high explosives is described. Particular emphasis is placed on use of the quadrupole ion trap as the type of tandem mass spectrometer. Atmospheric sampling glow discharge provides a simple, rugged, and efficient means for anion formation while the quadrupole ion trap provides for efficient tandem mass spectrometry. Mass selective ion accumulation and non-specific ion activation methods can be used to overcome deleterious effects arising from ion/ion interactions. Such interactions constitute the major potential technical barrier to the use of the ion trap for real-time monitoring of targeted compounds in uncontrolled and highly variable matrices. Tailored waveforms can be used to effect both mass selective ion accumulation and ion activation. Concatenated tailored waveforms allow for both functions in a single experiment thereby providing the capability for monitoring several targeted species simultaneously. The combination of atmospheric sampling glow discharge ionization with a state-of-the-art analytical quadrupole ion trap is a highly sensitive and specific detector for traces of high explosives. The combination is also small and inexpensive relative to virtually any other form of tandem mass spectrometry. The science and technology underlying the glow discharge/ion trap combination is sufficiently mature to form the basis for an engineering effort to make the detector portable. 85 refs.

  1. Introduction Melt inclusions (figure 1) found in mineral grains as tiny droplets trapped during crystal growth offer a

    E-Print Network [OSTI]

    Kidd, William S. F.

    breakdown, and they may be enriched in some sedimentary rocks (Cookenboo, et al. 1997;Dewey and Mange,1999 spinels (the best fit lines and fields are from Kamenetsky, et al. 2001). Continuous line in a. is a power

  2. Excessive Balmer line broadening in a plane cathode abnormal glow discharge in hydrogen

    SciTech Connect (OSTI)

    Cvetanovic, N.; Kuraica, M.M.; Konjevic, N. [Center for Science and Development of Technology, Obilicev Venac 26, Belgrade, and Faculty of Transport and Traffic Engineering, University of Belgrade, V. Stepe 305, Belgrade (Serbia and Montenegro); Faculty of Physics, University of Belgrade, P.O. Box 368, 11001 Belgrade, and Center for Science and Development of Technology, Obilicev Venac 26, Belgrade (Serbia and Montenegro); Faculty of Physics, University of Belgrade, P.O. Box 368, 11001 Belgrade (Serbia and Montenegro)

    2005-02-01T23:59:59.000Z

    Results of a Doppler spectroscopy study of the hydrogen Balmer alpha line in an abnormal glow discharge operated in pure hydrogen are reported. Measurements of line shapes are performed side-on to the discharge axis in a low electric field region of negative glow. The excessive Balmer alpha broadening is detected and its presence and linewidth is related to the collisions of fast hydrogen atoms with molecular hydrogen. The collision model enabled also an estimation of effective cross section data from the Balmer alpha axial intensity decay curves. Large excessive Balmer alpha line broadening in pure hydrogen and its dependence upon the direction of observation with respect to the electric field is in contradiction to the resonance transfer model, proposed byMills et al. in several publications [see, e.g., IEEE Trans. Plasma Sci. 31, 338 (2003)].

  3. Time series analysis of ionization waves in dc neon glow discharge

    SciTech Connect (OSTI)

    Hassouba, M. A.; Al-Naggar, H. I.; Al-Naggar, N. M.; Wilke, C. [Department of Physics, Faculty of Science, Benha University (Egypt); Institute of Physics, E. M. A. University, Domstrasse 10a, 17489 Greifswald (Germany)

    2006-07-15T23:59:59.000Z

    The dynamics of dc neon glow discharge is examined by calculating a Lyapunov exponent spectrum (LES) and correlation dimension (D{sub corr}) from experimental time series. The embedding theory is used to reconstruct an attractor with the delay coordinate method. The analysis refers to periodic, chaotic, and quasi-periodic attractors. The results obtained are confirmed by a comparison with other methods of time series analysis such as the Fourier power spectrum and autocorrelation function. The main object of the present work is the positive column of a dc neon glow discharge. The positive column is an excellent model for the study of a non-linearity plasma system because it is nonisothermal plasma far from equilibrium.

  4. Investigation of complexity dynamics of inverse and normal homoclinic bifurcation in a glow discharge plasma

    SciTech Connect (OSTI)

    Saha, Debajyoti, E-mail: debajyoti.saha@saha.ac.in; Kumar Shaw, Pankaj; Janaki, M. S.; Sekar Iyengar, A. N.; Ghosh, Sabuj; Mitra, Vramori, E-mail: vramorimitra@yahoo.com; Michael Wharton, Alpha [Plasma Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India)] [Plasma Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India)

    2014-03-15T23:59:59.000Z

    Order-chaos-order was observed in the relaxation oscillations of a glow discharge plasma with variation in the discharge voltage. The first transition exhibits an inverse homoclinic bifurcation followed by a homoclinic bifurcation in the second transition. For the two regimes of observations, a detailed analysis of correlation dimension, Lyapunov exponent, and Renyi entropy was carried out to explore the complex dynamics of the system.

  5. Mechanism behind self-sustained oscillations in direct current glow discharges and dusty plasmas

    SciTech Connect (OSTI)

    Cho, Sung Nae [Devices R and D Center, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., Mt. 14-1 Nongseo-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-712 (Korea, Republic of)

    2013-04-15T23:59:59.000Z

    An alternative explanation to the mechanism behind self-sustained oscillations of ions in direct current (DC) glow discharges is provided. Such description is distinguished from the one provided by the fluid models, where oscillations are attributed to the positive feedback mechanism associated with photoionization of particles and photoemission of electrons from the cathode. Here, oscillations arise as consequence of interaction between an ion and the surface charges induced by it at the bounding electrodes. Such mechanism provides an elegant explanation to why self-sustained oscillations occur only in the negative resistance region of the voltage-current characteristic curve in the DC glow discharges. Furthermore, this alternative description provides an elegant explanation to the formation of plasma fireballs in the laboratory plasma. It has been found that oscillation frequencies increase with ion's surface charge density, but at the rate which is significantly slower than it does with the electric field. The presented mechanism also describes self-sustained oscillations of ions in dusty plasmas, which demonstrates that self-sustained oscillations in dusty plasmas and DC glow discharges involve common physical processes.

  6. Atmospheric sampling glow discharge ionizataion and triple quadrupole tandem mass spectrometry for explosives vapor detection

    SciTech Connect (OSTI)

    McLuckey, S.A.; Goeringer, D.E.; Asano, K.G.; Hart, K.J.; Glish, G.L.; Grant, B.C.; Chambers, D.M.

    1993-08-01T23:59:59.000Z

    The detection and identification of trace vapors of hidden high explosives is an excellent example of a targeted analysis problem. It is desirable to push to ever lower levels the quantity or concentration of explosives material that provides an analytical signal, while at the same time discriminating against all other uninteresting material. The detection system must therefore combine high sensitivity with high specificity. This report describes the philosophy behind the use of atmospheric sampling glow discharge ionization, which is a sensitive, rugged, and convenient means for forming anions from explosives molecules, with tandem mass spectrometry, which provides unparalleled specificity in the identification of explosives-related ions. Forms of tandem mass spectrometry are compared and contrasted to provide a summary of the characteristics to be expected from an explosives detector employing mass spectrometry/mass spectrometry. The instrument developed for the FAA, an atmospheric sampling glow discharge/triple quadrupole mass spectrometer, is described in detail with particular emphasis on the ion source/spectrometer interface and on the capabilities of the spectrometer. Performance characteristics of the system are also described as they pertain to explosives of interest including a description of an automated procedure for the detection and identification of specific explosives. A comparison of various tandem mass spectrometers mated with atmospheric sampling glow discharge is then described and preliminary studies with a vapor preconcentration system provided by the FAA will be described.

  7. Glow discharge cleaning and vacuum deposition of copper on 6061-T6 aluminum

    SciTech Connect (OSTI)

    Vasofsky, R.W.; Corbett, W.D. Jr.

    1991-02-25T23:59:59.000Z

    Prior to plating electroless nickel onto a part made of 6061-T6 aluminum, several aqueous pretreatment steps are required which end with the deposition of a thin copper layer covering the part. In an effort to minimize the quantity and type of wastes generated during this pretreatment process, vacuum deposition methods are under evaluation as an alternative. Six vacuum cleaning/copper deposition experiments have been conducted on 6061-T6 aluminum coupons. The coupons were glow discharge cleaned at 1500, 2000 and 2500 volts and a copper coating was either sputtered deposited or ion plated onto the aluminum substrate. The results showed that the adhesive strength of the copper coating was greatest for those coupons cleaned at 2500 volts and ion plated. Glow discharge cleaning was greatest for those coupons cleaned at 2500 volts and ion plated. Glow discharge cleaning at 1500 and 2000 volts resulted in copper films that were porous while those cleaned at 2500 volts were not. The results further showed that ion plated copper films of appropriate thickness can be produced while the aluminum alloy is precipitation hardened. 3 refs., 9 figs., 3 tabs.

  8. Bacteria with tiny projections can make efficient fuel cells September 7th, 2009 -3:52 pm ICT by ANI -

    E-Print Network [OSTI]

    Lovley, Derek

    the University of Massachusetts, US. The researchers isolated a strain of Geobacter sulfurreducens, which biofilm on the anode surface, which conducted electricity. The researchers found large quantities of pilin, a protein that makes the tiny fibres that conduct electricity through the sticky biofilm. "The filaments

  9. tinyMoBot: A Platform for Mobile Sensor Networks Torsten Stremlau, Christoph Weyer, and Volker Turau

    E-Print Network [OSTI]

    Turau, Volker

    tinyMoBot: A Platform for Mobile Sensor Networks Torsten Stremlau, Christoph Weyer, and Volker or the whole network consist of mobile sen- sor nodes. Currently, no common platform is available. This paper are able to communicate with static nodes. Since a general mobile sensor network platform is not available

  10. Nonlocal control of electron temperature in short direct current glow discharge plasma

    SciTech Connect (OSTI)

    Demidov, V. I. [Department of Optics and Spectroscopy, St. Petersburg State University, St. Petersburg 199034 (Russian Federation); International Laboratory “Nonlocal Plasma in Nanotechnology and Medicine”, ITMO University, Kronverkskiy pr. 49, St. Petersburg 197101 (Russian Federation); Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States); Kudryavtsev, A. A.; Stepanova, O. M. [Department of Optics and Spectroscopy, St. Petersburg State University, St. Petersburg 199034 (Russian Federation); Kurlyandskaya, I. P. [International Laboratory “Nonlocal Plasma in Nanotechnology and Medicine”, ITMO University, Kronverkskiy pr. 49, St. Petersburg 197101 (Russian Federation); St. Petersburg University of State Fire Service of EMERCOM RF, Murmansk Branch, Murmansk 183040 (Russian Federation)

    2014-09-15T23:59:59.000Z

    To demonstrate controlling the electron temperature in nonlocal plasma, experiments have been performed on a short (without positive column) dc glow discharge with a cold cathode by applying different voltages to the conducting discharge wall. The experiments have been performed for low-pressure noble gas discharges. The applied voltage can modify trapping the energetic electrons emitted from the cathode sheath and arising from the atomic and molecular processes in the plasma within the device volume. This phenomenon results in the energetic electrons heating the slow plasma electrons, which consequently modifies the electron temperature. Furthermore, a numerical model of the discharge has demonstrated the electron temperature modification for the above case.

  11. External magnetic field influence on H{sub {alpha}} line in abnormal glow discharge

    SciTech Connect (OSTI)

    Obradovic, B.M.; Dojcinovic, I.P.; Kuraica, M.M.; Puric, J. [Faculty of Physics, University of Belgrade, P.O. Box 368, 11001 Belgrade (Serbia and Montenegro) and Center for Science and Development of Technology, Obilicev Venac 26, 11001 Belgrade (Serbia and Montenegro)

    2006-04-03T23:59:59.000Z

    Influence of the external axial magnetic field on the hydrogen H{sub {alpha}} line profiles in an abnormal glow discharge has been studied. It has been found that the applied magnetic field predominantly increases the intensity of central component of the characteristic excessively broadened H{sub {alpha}} profile. Magnetic filed causes helical motion of electrons along the electric field lines and prolongs their trajectories increasing the number of collisions with matrix gas. This explains the increase of the central component of H{sub {alpha}} profile and can be regarded as an experimental proof for the main contribution of electron excitation to that part of the profile.

  12. Hardware Lab-1: TinyOS Setup Duration 2 weeks TinyOS is the operating environment that you will be using for your project and details on how to

    E-Print Network [OSTI]

    Hu, Fei

    /apps/TestTimeStamping o $TOSROOT/tos: Main directory of TinyOS o $TOSROOT/tos/interface: definition of interfaces Timer, TimeStamping, SendMsg, ReceiveMsg, GenericComm o $TOSROOT/tos/platform: hardware specific components Ex: Radio o $TOSROOT/tos/system: Standard components Ex: TimerC, LedsC Look in to this first when looking

  13. Influence of the transverse dimension on the structure and properties of dc glow discharges

    SciTech Connect (OSTI)

    Bogdanov, E. A. [St. Petersburg State University, St. Petersburg 198904 (Russian Federation); Adams, S. F. [Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States); Demidov, V. I. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States); Kudryavtsev, A. A. [Department of Optics, St. Petersburg State University, St. Petersburg 198904 (Russian Federation); Williamson, J. M. [UES, Inc., 4401 Dayton-Xenia Rd., Beavercreek, Ohio 45432 (United States)

    2010-10-15T23:59:59.000Z

    Two-dimensional (2D) simulations of a dc glow discharge with a cold cathode in argon have been performed for various radii of the discharge tube. It is shown that the loss of the charged particles to the walls can significantly affect plasma parameters as well as properties of the cathode sheath. The longitude dimensions of the negative glow and Faraday dark space depend on the transverse loss of the charge particles and are not consistently predicted with a 1D model. The common assumption that the cathode sheath can be analyzed independently of the plasma also may not be valid. The transverse inhomogeneity of the plasma leads to a change in the current density distribution over the cathode surface. The thickness of the cathode sheath can vary with radial distance from the discharge axis, even for the case of negligible radial loss of the charge particles. The 2D model results provide an analysis of the conditions of applicability of the 1D model.

  14. Investigation of helium ion production in constricted direct current plasma ion source with layered-glows

    SciTech Connect (OSTI)

    Lee, Yuna [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Chung, Kyoung-Jae, E-mail: jkjlsh1@snu.ac.kr [Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Park, Yeong-Shin [Samsumg Electronics Co. Ltd., Gyeonggi 445-701 (Korea, Republic of)] [Samsumg Electronics Co. Ltd., Gyeonggi 445-701 (Korea, Republic of); Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of) [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

    2014-02-15T23:59:59.000Z

    Generation of helium ions is experimentally investigated with a constricted direct current (DC) plasma ion source operated at layered-glow mode, in which electrons could be accelerated through multiple potential structures so as to generate helium ions including He{sup 2+} by successive ionization collisions in front of an extraction aperture. The helium discharge is sustained with the formation of a couple of stable layers and the plasma ball with high density is created near the extraction aperture at the operational pressure down to 0.6 Torr with concave cathodes. The ion beam current extracted with an extraction voltage of 5 kV is observed to be proportional to the discharge current and inversely proportional to the operating pressure, showing high current density of 130 mA/cm{sup 2} and power density of 0.52 mA/cm{sup 2}/W. He{sup 2+} ions, which were predicted to be able to exist due to multiple-layer potential structure, are not observed. Simple calculation on production of He{sup 2+} ions inside the plasma ball reveals that reduced operating pressure and increased cathode area will help to generate He{sup 2+} ions with the layered-glow DC discharge.

  15. Growth of tungsten nanoparticles in direct-current argon glow discharges

    SciTech Connect (OSTI)

    Kishor Kumar, K.; Coueedel, L.; Arnas, C. [Laboratoire de Physique des Interactions Ioniques et Moleculaires, CNRS-Aix-Marseille Universite, 13397 Marseille (France)

    2013-04-15T23:59:59.000Z

    The growth of nanoparticles from the sputtering of a tungsten cathode in DC argon glow discharges is reported. The study was performed at fixed argon pressure and constant discharge current. The growth by successive agglomerations is evidenced. First, tungsten nanocrystallites agglomerate into primary particles, the most probable size of which being {approx}30 nm. Primary particles of this size are observed for all plasma durations and always remain the most numerous in the discharge. Primary particles quickly agglomerate to form particles with size up to {approx}150 nm. For short plasma duration, log-normal functions describe accurately the dust particle size distributions. On the contrary, for long discharge durations, a second hump appears in the distributions toward large particle sizes. In the meantime, the discharge voltage, electron density, and emission line intensities strongly evolve. Their evolutions can be divided in four separate phases and exhibit unusual distinctive features compared to earlier observations in discharges in which particles were growing. The evolution of the different parameters is explained by a competition between the surface state of the tungsten cathode and the influence of the growing nanoparticles. The differences with sputtering glow discharges and chemically active plasmas suggest that the nanoparticle growth and its influence on discharge parameters is system and material dependent.

  16. Radio-frequency powered glow discharge device and method with high voltage interface

    DOE Patents [OSTI]

    Duckworth, Douglas C. (Knoxville, TN); Marcus, R. Kenneth (Clemson, SC); Donohue, David L. (Vienna, AT); Lewis, Trousdale A. (Oak Ridge, TN)

    1994-01-01T23:59:59.000Z

    A high voltage accelerating potential, which is supplied by a high voltage direct current power supply, is applied to the electrically conducting interior wall of an RF powered glow discharge cell. The RF power supply desirably is electrically grounded, and the conductor carrying the RF power to the sample held by the probe is desirably shielded completely excepting only the conductor's terminal point of contact with the sample. The high voltage DC accelerating potential is not supplied to the sample. A high voltage capacitance is electrically connected in series between the sample on the one hand and the RF power supply and an impedance matching network on the other hand. The high voltage capacitance isolates the high DC voltage from the RF electronics, while the RF potential is passed across the high voltage capacitance to the plasma. An inductor protects at least the RF power supply, and desirably the impedance matching network as well, from a short that might occur across the high voltage capacitance. The discharge cell and the probe which holds the sample are configured and disposed to prevent the probe's components, which are maintained at ground potential, from bridging between the relatively low vacuum region in communication with the glow discharge maintained within the cell on the one hand, and the relatively high vacuum region surrounding the probe and cell on the other hand. The probe and cell also are configured and disposed to prevent the probe's components from electrically shorting the cell's components.

  17. Radio-frequency powered glow discharge device and method with high voltage interface

    DOE Patents [OSTI]

    Duckworth, D.C.; Marcus, R.K.; Donohue, D.L.; Lewis, T.A.

    1994-06-28T23:59:59.000Z

    A high voltage accelerating potential, which is supplied by a high voltage direct current power supply, is applied to the electrically conducting interior wall of an RF powered glow discharge cell. The RF power supply desirably is electrically grounded, and the conductor carrying the RF power to the sample held by the probe is desirably shielded completely excepting only the conductor's terminal point of contact with the sample. The high voltage DC accelerating potential is not supplied to the sample. A high voltage capacitance is electrically connected in series between the sample on the one hand and the RF power supply and an impedance matching network on the other hand. The high voltage capacitance isolates the high DC voltage from the RF electronics, while the RF potential is passed across the high voltage capacitance to the plasma. An inductor protects at least the RF power supply, and desirably the impedance matching network as well, from a short that might occur across the high voltage capacitance. The discharge cell and the probe which holds the sample are configured and disposed to prevent the probe's components, which are maintained at ground potential, from bridging between the relatively low vacuum region in communication with the glow discharge maintained within the cell on the one hand, and the relatively high vacuum region surrounding the probe and cell on the other hand. The probe and cell also are configured and disposed to prevent the probe's components from electrically shorting the cell's components. 11 figures.

  18. Signal transduction research has made some glowing progress in the past 12 months. Recent advances in fluorescent

    E-Print Network [OSTI]

    Tsien, Roger Y.

    416 Signal transduction research has made some glowing progress in the past 12 months. Recent Medical Institute, 310 Cellular and Molecular Medicine West, 0647, University of California at San Diego Progress in understanding signal transduction, especially in complex tissues such as those found

  19. Design and construction of uniform glow discharge plasma system operating under atmospheric condition

    SciTech Connect (OSTI)

    Kocum, C.; Ayhan, H. [Biomedical Engineering Department, Baskent University, Ankara 06530 (Turkey); Chemistry Department, Biochemistry Division, Mugla University, Faculty of Science, Koetekli, 48170 Mugla (Turkey)

    2007-06-15T23:59:59.000Z

    The design of a uniform glow discharge plasma system operating without vacuum is presented. A full-bridge switching circuit was used to switch the transformers. The primary windings of transformers were connected in parallel, but in opposite phase to double the output voltage. Theoretically, 20 000 V{sub pp} was obtained. Rectangle copper electrodes were used, and placed parallel to each other. To prevent the spark production that is, to obtain uniformity, two 2 mm Teflon sheets were glued to the electrodes. However, it was observed that the operating frequency also affected the uniformity. For the system presented here, the frequency at which more uniformity was obtained was found to be 14 kHz.

  20. Improved ion implant fluence uniformity in hydrogen enhanced glow discharge plasma immersion ion implantation into silicon

    SciTech Connect (OSTI)

    Luo, J. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Department of 702, Beihang University, Beijing 100191 (China); Li, L. H., E-mail: liliuhe@buaa.edu.cn, E-mail: paul.chu@cityu.edu.hk; Liu, H. T.; Xu, Y.; Zuo, X. J.; Zhu, P. Z.; Ma, Y. F. [Department of 702, Beihang University, Beijing 100191 (China); Yu, K. M. [Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States); Fu, Ricky K. Y.; Chu, Paul K., E-mail: liliuhe@buaa.edu.cn, E-mail: paul.chu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

    2014-06-15T23:59:59.000Z

    Enhanced glow discharge plasma immersion ion implantation does not require an external plasma source but ion focusing affects the lateral ion fluence uniformity, thereby hampering its use in high-fluence hydrogen ion implantation for thin film transfer and fabrication of silicon-on-insulator. Insertion of a metal ring between the sample stage and glass chamber improves the ion uniformity and reduces the ion fluence non-uniformity as the cathode voltage is raised. Two-dimensional multiple-grid particle-in-cell simulation confirms that the variation of electric field inside the chamber leads to mitigation of the ion focusing phenomenon and the results are corroborated experimentally by hydrogen forward scattering.

  1. Non-local Effects in a Stratified Glow Discharge With Dusty Particles

    SciTech Connect (OSTI)

    Sukhinin, G. I. [Institute of Thermophysics SB RAS, Lavrentyev Ave., 1, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Pirogova Str., 2, Novosibirsk, 630090 (Russian Federation); Fedoseev, A. V. [Institute of Thermophysics SB RAS, Lavrentyev Ave., 1, Novosibirsk, 630090 (Russian Federation); Ramazanov, T. S.; Amangaliyeva, R. Zh.; Dosbolayev, M. K.; Jumabekov, A. N. [Institute of Experimental and Theoretical Physics, Al Farabi Kazakh National University, Tole Bi, 96a, Almaty, 050012 (Kazakhstan)

    2008-09-07T23:59:59.000Z

    The work is aimed to describe non-local effects in the positive column of a low pressure stratified DC glow discharge in argon with dusty particles in a vertical cylindrical discharge tube. The numerical calculations of plasma parameters in the axis of the discharge tube were performed with the help of hybrid model based on the solution of non-local Boltzmann equation for EEDF. Distributions of optical emission from striations were measured experimentally. It is shown that in a stratified positive column the EEDF is not Maxwellian and even non-monotonous. Also, the effect of displacing of optical emission distribution relative to the electric field is shown both by numerical simulation and experimental measurements.

  2. Dynamic contraction of the positive column of a self-sustained glow discharge in air flow

    SciTech Connect (OSTI)

    Shneider, M. N. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States)] [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Mokrov, M. S. [Institute for Problems in Mechanics, RAS, Moscow (Russian Federation)] [Institute for Problems in Mechanics, RAS, Moscow (Russian Federation); Milikh, G. M. [Department of Astronomy, University of Maryland, College Park, Maryland 20742 (United States)] [Department of Astronomy, University of Maryland, College Park, Maryland 20742 (United States)

    2014-03-15T23:59:59.000Z

    We study the dynamic contraction of a self-sustained glow discharge in air in a rectangular duct with convective cooling. A two dimensional numerical model of the plasma contraction was developed in a cylindrical frame. The process is described by a set of time-dependent continuity equations for the electrons, positive and negative ions; gas and vibrational temperature; and equations which account for the convective heat and plasma losses by the transverse flux. Transition from the uniform to contracted state was analyzed. It was shown that such transition experiences a hysteresis, and that the critical current of the transition increases when the gas density drops. Possible coexistence of the contracted and uniform state of the plasma in the discharge, where the current flows along the density gradient of the background gas, is discussed.

  3. A New Pulsed Glow Discharge Source With Enhanced Ion Extraction for Small Non-Conductive Samples or Atmospheric Sampling

    SciTech Connect (OSTI)

    Jackson, Glen P. [Ohio University, Athens; Haire, Richard {Dick} G [ORNL; Duckworth, Douglas {Doug} C [ORNL

    2003-04-01T23:59:59.000Z

    An ionization source designed to efficiently utilize sub-milligram quantities of electrically non-conducting compounds (i.e. oxides) for prolonged periods of mass spectrometric analysis is described. The source is coupled to a quadrupole ion trap mass spectrometer in this report, but could readily be modified for alternative types of mass spectrometers. The coaxial-design glow discharge ion source is unique in that it incorporates a focusing lens behind the discharge surface to steer ions towards the ion sampling plate and thereby improve sensitivity. Non-conducting oxide samples are infused in indium and set in one end of an electrically conductive rod, to which the voltage is applied. Transmission efficiency is sufficient to allow the measurement of isotopes of tungsten from a tungsten rod using glow discharge pulse widths as narrow as 2 {micro}s, which is on the order of single-atom layer sputtering. The sputtering and ionization processes occurring in the discharge produces mainly atomic metal ions, regardless of the chemical form of the metals in the samples. This latter aspect is particularly useful for intended applications involving actinide samples, and allows a minimal amount of sample handling. In a second application, a metal capillary is used in place of the rod to create an atmospheric sampling glow discharge. In this mode, the ion-focusing lens was also found to enhance ion signals arising from volatile vapors entering the discharge from the capillary.

  4. Array of surface-confined glow discharges in atmospheric pressure helium: Modes and dynamics

    SciTech Connect (OSTI)

    Li, D.; Liu, D. X., E-mail: liudingxin@gmail.com, E-mail: mglin5g@gmail.com [Center for Plasma Biomedicine, State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi (China); Nie, Q. Y.; Li, H. P. [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Chen, H. L. [Frank Reidy Center for Bioelectrics, Old Dominion University, Norfolk, Virginia 23508 (United States); Kong, M. G., E-mail: liudingxin@gmail.com, E-mail: mglin5g@gmail.com [Center for Plasma Biomedicine, State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi (China); Frank Reidy Center for Bioelectrics, Old Dominion University, Norfolk, Virginia 23508 (United States); Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia 23529 (United States)

    2014-05-19T23:59:59.000Z

    Array of atmospheric pressure surface discharges confined by a two-dimensional hexagon electrode mesh is studied for its discharge modes and temporal evolution so as to a theoretical underpinning to their growing applications in medicine, aerodynamic control, and environmental remediation. Helium plasma surface-confined by one hexagon-shaped rim electrode is shown to evolve from a Townsend mode to a normal and abnormal glow mode, and its evolution develops from the rim electrodes as six individual microdischarges merging in the middle of the hexagon mesh element. Within one hexagon element, microdischarges remain largely static with the mesh electrode being the instantaneous cathode, but move towards the hexagon center when the electrode is the instantaneous anode. On the entire array electrode surface, plasma ignition is found to beat an unspecific hexagon element and then spreads to ignite surrounding hexagon elements. The spreading of microdischarges is in the form of an expanding circle at a speed of about 3?×?10{sup 4} m/s, and their quenching starts in the location of the initial plasma ignition. Plasma modes influence how input electrical power is used to generate and accelerate electrons and as such the reaction chemistry, whereas plasma dynamics are central to understand and control plasma instabilities. The present study provides an important aspect of plasma physics of the atmospheric surface-confined discharge array and a theoretical underpinning to its future technological innovation.

  5. Light Sets Tiny Objects Aquiver --Cho 2005 (712): 2 --sciencenow http://sciencenow.sciencemag.org/cgi/content/full/2005/712/2 1 of 2 7/14/2005 11:55 AM

    E-Print Network [OSTI]

    Light Sets Tiny Objects Aquiver -- Cho 2005 (712): 2 -- sciencenow http://sciencenow.sciencemag.org/cgi/content/full/2005/712/2 1 of 2 7/14/2005 11:55 AM Hum along. Light pressure sets a tiny glass disk vibrating: Caltech Library System | Sign In as Individual | FAQ | Access Rights | Join AAAS 12 July 2005 Light Sets

  6. ig research into the tiny world of nanotechnology received a giant boost with the establishment of the Russell Berrie Nanotechnology Institute (RBNI) at the

    E-Print Network [OSTI]

    Rimon, Elon

    B ig research into the tiny world of nanotechnology received a giant boost with the establishment of the Russell Berrie Nanotechnology Institute (RBNI) at the Technion. "The Technion's ranking as a world leader in nanotechnology strongly influenced our decision," said Angelica Berrie, president of the Russell Berrie

  7. Etching of UO{sub 2} in NF{sub 3} RF Plasma Glow Discharge

    SciTech Connect (OSTI)

    John M. Veilleux

    1999-08-01T23:59:59.000Z

    A series of room temperature, low pressure (10.8 to 40 Pa), low power (25 to 210 W) RF plasma glow discharge experiments with UO{sub 2} were conducted to demonstrate that plasma treatment is a viable method for decontaminating UO{sub 2} from stainless steel substrates. Experiments were conducted using NF{sub 3} gas to decontaminate depleted uranium dioxide from stainless-steel substrates. Depleted UO{sub 2} samples each containing 129.4 Bq were prepared from 100 microliter solutions of uranyl nitrate hexahydrate solution. The amorphous UO{sub 2} in the samples had a relatively low density of 4.8 gm/cm{sub 3}. Counting of the depleted UO{sub 2} on the substrate following plasma immersion was performed using liquid scintillation counting with alpha/beta discrimination due to the presence of confounding beta emitting daughter products, {sup 234}Th and {sup 234}Pa. The alpha emission peak from each sample was integrated using a gaussian and first order polynomial fit to improve quantification. The uncertainties in the experimental measurement of the etched material were estimated at about {+-} 2%. Results demonstrated that UO{sub 2} can be completely removed from stainless-steel substrates after several minutes processing at under 200 W. At 180 W and 32.7 Pa gas pressure, over 99% of all UO{sub 2} in the samples was removed in just 17 minutes. The initial etch rate in the experiments ranged from 0.2 to 7.4 {micro}m/min. Etching increased with the plasma absorbed power and feed gas pressure in the range of 10.8 to 40 Pa. A different pressure effect on UO{sub 2} etching was also noted below 50 W in which etching increased up to a maximum pressure, {approximately}23 Pa, then decreased with further increases in pressure.

  8. Reactions of tungsten-titanium alloys with decomposition products from a glow UHF discharge in a tetrafluoromethane-oxygen mixture

    SciTech Connect (OSTI)

    Amirov, I.I.; Vinogradov, G.K.; Slovetskii, D.I.

    1988-07-01T23:59:59.000Z

    Decomposition products from tetrafluoromethane mixed with oxygen react with WTi alloy in an HF glow discharge, the extent of reaction being dependent on the atomic fluorine concentration, temperature, and surface potential. The rates of reaction with the CF/sub 4/ products are proportional to the atomic fluorine concentrations. The effective activation energies have been determined for the atomic fluorine reacting with the alloy components in various gases. The metal removal rate increases when the specimen is negative with respect to the plasma potential, which is ascribed to the surface being bombarded by positive ions or to the electric field affecting the surface reaction rates.

  9. Optomechanical Crystals

    E-Print Network [OSTI]

    Eichenfield, Matt; Camacho, Ryan M; Vahala, Kerry J; Painter, Oskar

    2009-01-01T23:59:59.000Z

    Structured, periodic optical materials can be used to form photonic crystals capable of dispersing, routing, and trapping light. A similar phenomena in periodic elastic structures can be used to manipulate mechanical vibrations. Here we present the design and experimental realization of strongly coupled optical and mechanical modes in a planar, periodic nanostructure on a silicon chip. 200-Terahertz photons are co-localized with mechanical modes of Gigahertz frequency and 100-femtogram mass. The effective coupling length, which describes the strength of the photon-phonon interaction, is as small as 2.9 microns, which, together with minute oscillator mass, allows all-optical actuation and transduction of nanomechanical motion with near quantum-limited sensitivity. Optomechanical crystals have many potential applications, from RF-over-optical communication to the study of quantum effects in mesoscopic mechanical systems.

  10. Tiny scale opacity fluctuations from VLBA, MERLIN and VLA observations of HI absorption toward 3C 138

    E-Print Network [OSTI]

    Roy, Nirupam; Goss, W M; Brogan, Crystal L; Lazio, T J W

    2012-01-01T23:59:59.000Z

    The structure function of opacity fluctuations is a useful statistical tool to study tiny scale structures of neutral hydrogen. Here we present high resolution observation of HI absorption towards 3C 138, and estimate the structure function of opacity fluctuations from the combined VLA, MERLIN and VLBA data. The angular scales probed in this work are ~ 10-200 milliarcsec (about 5-100 AU). The structure function in this range is found to be well represented by a power law S_tau(x) ~ x^{beta} with index beta ~ 0.33 +/- 0.07 corresponding to a power spectrum P_tau(U) ~ U^{-2.33}. This is slightly shallower than the earlier reported power law index of ~ 2.5-3.0 at ~ 1000 AU to few pc scales. The amplitude of the derived structure function is a factor of ~ 20-60 times higher than the extrapolated amplitude from observation of Cas A at larger scales. On the other hand, extrapolating the AU scale structure function for 3C 138 predicts the observed structure function for Cas A at the pc scale correctly. These results...

  11. Effect of hydrogen ratio on plasma parameters of N{sub 2}-H{sub 2} gas mixture glow discharge

    SciTech Connect (OSTI)

    El-Brulsy, R. A.; Abd Al-Halim, M. A.; Abu-Hashem, A. [Benha University, Physics Department, Faculty of Science (Egypt); Rashed, U. M. [Alazhar University, Physics Department, Faculty of Science (Egypt); Hassouba, M. A. [Benha University, Physics Department, Faculty of Science (Egypt)

    2012-05-15T23:59:59.000Z

    A dc plane glow discharge in a nitrogen-hydrogen (N{sub 2}-H{sub 2}) gas mixture has been operated at discharge currents of 10 and 20 mA. The electron energy distribution function (EEDF) at different hydrogen concentrations is measured. A Maxwellian EEDF is found in the positive column region, while in both cathode fall and negative glow regions, a non-Maxwellian one is observed. Langmuir electric probes are used at different axial positions, gas pressures, and hydrogen concentrations to measure the electron temperature and plasma density. The electron temperature is found to increase with increasing H{sub 2} concentration and decrease with increasing both the axial distance from the cathode and the mixture pressure. At first, with increasing distance from the cathode, the ion density decreases, while the electron density increases; then, as the anode is further approached, they remain nearly constant. At different H{sub 2} concentrations, the electron and ion densities decrease with increasing the mixture pressure. Both the electron and ion densities slightly decrease with increasing H{sub 2} concentration.

  12. Final Report DE-FG02-00ER54583: "Physics of Atmospheric Pressure Glow Discharges" and "Nanoparticle Nucleation and Dynamics in Low-Pressure Plasmas"

    SciTech Connect (OSTI)

    Uwe Kortshagen; Joachim Heberlein; Steven L. Girshick

    2009-06-01T23:59:59.000Z

    This project was funded over two periods of three years each, with an additional year of no-cost extension. Research in the first funding period focused on the physics of uniform atmospheric pressure glow discharges, the second funding period was devoted to the study of the dynamics of nanometer-sized particles in plasmas.

  13. J. Phys. III IYance 7 (1997) 927-936 APRIL 1997, PAGE 927 A Stable Discharge Glow in Gas Discharge System with

    E-Print Network [OSTI]

    Boyer, Edmond

    1997-01-01T23:59:59.000Z

    have been stud- ied in a wide range of the gas pressure p (21.3-466.5 hPa) and of interJ. Phys. III IYance 7 (1997) 927-936 APRIL 1997, PAGE 927 A Stable Discharge Glow in Gas Discharge.40.Sx Metal-semiconductor-metal structures Abstract. A dc discharge generated between parallel plate

  14. Monochromator Crystal Glitch Library

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    SSRL's Monochromator Crystal Glitch Library allows users to view glitch spectra online, list specific crystal orientations, and download PDF files of the glitch spectra. (Specialized Interface)

  15. Mixed crystal organic scintillators

    DOE Patents [OSTI]

    Zaitseva, Natalia P; Carman, M Leslie; Glenn, Andrew M; Hamel, Sebastien; Hatarik, Robert; Payne, Stephen A; Stoeffl, Wolfgang

    2014-09-16T23:59:59.000Z

    A mixed organic crystal according to one embodiment includes a single mixed crystal having two compounds with different bandgap energies, the organic crystal having a physical property of exhibiting a signal response signature for neutrons from a radioactive source, wherein the signal response signature does not include a significantly-delayed luminescence characteristic of neutrons interacting with the organic crystal relative to a luminescence characteristic of gamma rays interacting with the organic crystal. According to one embodiment, an organic crystal includes bibenzyl and stilbene or a stilbene derivative, the organic crystal having a physical property of exhibiting a signal response signature for neutrons from a radioactive source.

  16. Pressure cryocooling protein crystals

    DOE Patents [OSTI]

    Kim, Chae Un (Ithaca, NY); Gruner, Sol M. (Ithaca, NY)

    2011-10-04T23:59:59.000Z

    Preparation of cryocooled protein crystal is provided by use of helium pressurizing and cryocooling to obtain cryocooled protein crystal allowing collection of high resolution data and by heavier noble gas (krypton or xenon) binding followed by helium pressurizing and cryocooling to obtain cryocooled protein crystal for collection of high resolution data and SAD phasing simultaneously. The helium pressurizing is carried out on crystal coated to prevent dehydration or on crystal grown in aqueous solution in a capillary.

  17. Modification of Thermal Emission via Metallic Photonic Crystals

    SciTech Connect (OSTI)

    Norris, David J.; Stein, Andreas; George, Steven M.

    2012-07-30T23:59:59.000Z

    Photonic crystals are materials that are periodically structured on an optical length scale. It was previously demonstrated that the glow, or thermal emission, of tungsten photonic crystals that have a specific structure - known as the 'woodpile structure' - could be modified to reduce the amount of infrared radiation from the material. This ability has implications for improving the efficiency of thermal emission sources and for thermophotovoltaic devices. The study of this effect had been limited because the fabrication of metallic woodpile structures had previously required a complex fabrication process. In this project we pursued several approaches to simplify the fabrication of metallic photonic crystals that are useful for modification of thermal emission. First, we used the self-assembly of micrometer-scale spheres into colloidal crystals known as synthetic opals. These opals can then be infiltrated with a metal and the spheres removed to obtain a structure, known as an inverse opal, in which a three-dimensional array of bubbles is embedded in a film. Second, we used direct laser writing, in which the focus of an infrared laser is moved through a thin film of photoresist to form lines by multiphoton polymerization. Proper layering of such lines can lead to a scaffold with the woodpile structure, which can be coated with a refractory metal. Third, we explored a completely new approach to modified thermal emission - thin metal foils that contain a simple periodic surface pattern, as shown in Fig. 1. When such a foil is heated, surface plasmons are excited that propagate along the metal interface. If these waves strike the pattern, they can be converted into thermal emission with specific properties.

  18. Experimental Analysis and Numerical Simulation of Tensile Behaviour of TiNi Shape Memory Alloy Fibres Reinforced Epoxy Matrix Composite at High Temperatures

    SciTech Connect (OSTI)

    Sahli, M. L.; Necib, B. [Mechanics Laboratory, Faculty of Engineering Sciences, University Mentouri Constantine, 25000 (Algeria)

    2011-05-04T23:59:59.000Z

    The shape memory alloys (SMA) possess both sensing and actuating functions due to their shape memory effect, pseudo-elasticity, high damping capability and other remarkable properties. Combining the SMA with other materials can create intelligent or smart composites. The epoxy resin composites filled with TiNi alloys fibres were fabricated and their mechanical properties have been investigated. In this study, stress/strain relationships for a composite with embedded shape memory materials (SMA) fibres are presented. The paper illustrates influence of the SMA fibres upon changes in mechanical behaviour of a composite plate with the SMA components, firstly and secondly, the actuating ability and reliability of shape memory alloy hybrid composites.

  19. Continuous wavelet transform based time-scale and multi-fractal analysis of the nonlinear oscillations in a hollow cathode glow discharge plasma

    E-Print Network [OSTI]

    Md. Nurujjaman; Ramesh Narayanan; A. N. Sekar Iyengar

    2009-09-12T23:59:59.000Z

    Continuous wavelet transform (CWT) based time-scale and multi-fractal analyses have been carried out on the anode glow related nonlinear floating potential fluctuations in a hollow cathode glow discharge plasma. CWT has been used to obtain the contour and ridge plots. Scale shift (or inversely frequency shift) which is a typical nonlinear behaviour, has been detected from the undulating contours. From the ridge plots, we have identified the presence of nonlinearity and degree of chaoticity. Using the wavelet transform modulus maxima technique we have obtained the multi-fractal spectrum for the fluctuations at different discharge voltages and the spectrum was observed to become a monofractal for periodic signals. These multi-fractal spectra were also used to estimate different quantities like the correlation and fractal dimension, degree of multi-fractality and complexity parameters. These estimations have been found to be consistent with the nonlinear time series analysis.

  20. Continuous wavelet transform based time-scale and multifractal analysis of the nonlinear oscillations in a hollow cathode glow discharge plasma

    SciTech Connect (OSTI)

    Nurujjaman, Md.; Narayanan, Ramesh; Iyengar, A. N. Sekar [Plasma Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India)

    2009-10-15T23:59:59.000Z

    Continuous wavelet transform (CWT) based time-scale and multifractal analyses have been carried out on the anode glow related nonlinear floating potential fluctuations in a hollow cathode glow discharge plasma. CWT has been used to obtain the contour and ridge plots. Scale shift (or inversely frequency shift), which is a typical nonlinear behavior, has been detected from the undulating contours. From the ridge plots, we have identified the presence of nonlinearity and degree of chaoticity. Using the wavelet transform modulus maxima technique we have obtained the multifractal spectrum for the fluctuations at different discharge voltages and the spectrum was observed to become a monofractal for periodic signals. These multifractal spectra were also used to estimate different quantities such as the correlation and fractal dimension, degree of multifractality, and complexity parameters. These estimations have been found to be consistent with the nonlinear time series analysis.

  1. CaF/sub 2/:Mn thermoluminescence: a single glow peak not described by 1st or 2nd order kinetics

    SciTech Connect (OSTI)

    Hornyak, W.F.; Levy, P.W.; Kierstead, J.A.

    1984-12-01T23:59:59.000Z

    The thermoluminescence (TL) of CaF/sub 2/:Mn has been studied using photon counting and digital recording. For doses of 10 rad or less the TL glow curves appear to consist of a single glow peak. However, there are indications - which are pronounced at larger doses - that one additional low intensity peak (area less than or equal to one percent) is superimposed on each side of the central peak. The intense peak is not described by 1st or 2nd order kinetics but is well described by the more general kinetics from which these kinetics are derived. These observations, and the results of additional kinetic analysis, demonstrate that retrapping is not negligible and may include all three peaks. In such systems, which are likely to include other dosimeter materials and minerals, peak height will not increase linearly with dose; an important factor for dosimetry and dating applications.

  2. CRYSTALLIZATION IN MULTICOMPONENT GLASSES

    SciTech Connect (OSTI)

    KRUGER AA; HRMA PR

    2009-10-08T23:59:59.000Z

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

  3. Experimental evidence of intermittent chaos in a glow discharge plasma without external forcing and its numerical modelling

    SciTech Connect (OSTI)

    Ghosh, S., E-mail: sabuj.ghosh@saha.ac.in; Kumar Shaw, Pankaj; Sekar Iyengar, A. N.; Janaki, M. S.; Saha, Debajyoti; Michael Wharton, Alpha [Plasma Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India)] [Plasma Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India); Mitra, Vramori [Purbasha Housing Estate, Kankurgachi, Kolkata 700054 (India)] [Purbasha Housing Estate, Kankurgachi, Kolkata 700054 (India)

    2014-03-15T23:59:59.000Z

    Intermittent chaos was observed in a glow discharge plasma as the system evolved from regular type of relaxation oscillations (of larger amplitude) to an irregular type of oscillations (of smaller amplitude) as the discharge voltage was increased. Floating potential fluctuations were analyzed by different statistical and spectral methods. Features like a gradual change in the normal variance of the interpeak time intervals, a dip in the skewness, and a hump in the kurtosis with variation in the control parameter have been seen, which are strongly indicative of intermittent behavior in the system. Detailed analysis also suggests that the intrinsic noise level in the experiment increases with the increasing discharge voltage. An attempt has been made to model the experimental observations by a second order nonlinear ordinary differential equation derived from the fluid equations for an unmagnetized plasma. Though the experiment had no external forcing, it was conjectured that the intrinsic noise in the experiment could be playing a vital role in the dynamics of the system. Hence, a constant bias and noise as forcing terms were included in the model. Results from the theoretical model are in close qualitative agreement with the experimental results.

  4. Photonic crystal light source

    DOE Patents [OSTI]

    Fleming, James G. (Albuquerque, NM); Lin, Shawn-Yu (Albuquerque, NM); Bur, James A. (Corrales, NM)

    2004-07-27T23:59:59.000Z

    A light source is provided by a photonic crystal having an enhanced photonic density-of-states over a band of frequencies and wherein at least one of the dielectric materials of the photonic crystal has a complex dielectric constant, thereby producing enhanced light emission at the band of frequencies when the photonic crystal is heated. The dielectric material can be a metal, such as tungsten. The spectral properties of the light source can be easily tuned by modification of the photonic crystal structure and materials. The photonic crystal light source can be heated electrically or other heating means. The light source can further include additional photonic crystals that exhibit enhanced light emission at a different band of frequencies to provide for color mixing. The photonic crystal light source may have applications in optical telecommunications, information displays, energy conversion, sensors, and other optical applications.

  5. Ion Coulomb Crystals

    E-Print Network [OSTI]

    Richard C. Thompson

    2014-11-18T23:59:59.000Z

    Ion Coulomb crystals (ICC), formed by atomic ions at low temperatures in radiofrequency and Penning ion traps, are structures that have remarkable properties and many applications. Images of Coulomb crystals are striking and reveal the crystal structure, which arises from a balance between the trapping forces acting on the ions and their mutual Coulomb repulsion. Applications of these structures range from frequency standards and quantum simulation through to measurement of the cross sections of chemical reactions of ions.

  6. Phononic crystal devices

    DOE Patents [OSTI]

    El-Kady, Ihab F. (Albuquerque, NM); Olsson, Roy H. (Albuquerque, NM)

    2012-01-10T23:59:59.000Z

    Phononic crystals that have the ability to modify and control the thermal black body phonon distribution and the phonon component of heat transport in a solid. In particular, the thermal conductivity and heat capacity can be modified by altering the phonon density of states in a phononic crystal. The present invention is directed to phononic crystal devices and materials such as radio frequency (RF) tags powered from ambient heat, dielectrics with extremely low thermal conductivity, thermoelectric materials with a higher ratio of electrical-to-thermal conductivity, materials with phononically engineered heat capacity, phononic crystal waveguides that enable accelerated cooling, and a variety of low temperature application devices.

  7. Liquid Crystal Optofluidics

    SciTech Connect (OSTI)

    Vasdekis, Andreas E.; Cuennet, J. G.; Psaltis, D.

    2012-10-11T23:59:59.000Z

    By employing anisotropic fluids and namely liquid crystals, fluid flow becomes an additional degree of freedom in designing optofluidic devices. In this paper, we demonstrate optofluidic liquid crystal devices based on the direct flow of nematic liquid crystals in microfluidic channels. Contrary to previous reports, in the present embodiment we employ the effective phase delay acquired by light travelling through flowing liquid crystal, without analysing the polarisation state of the transmitted light. With this method, we demonstrate the variation in the diffraction pattern of an array of microfluidic channels acting as a grating. We also discuss our recent activities in integrating mechanical oscillators for on-chip peristaltic pumping.

  8. 3/3/2014 Big ideas for tinywindmills at UTA | EnergyBiz http://www.energybiz.com/article/14/03/big-ideas-tiny-windmills-uta 1/3

    E-Print Network [OSTI]

    Chiao, Jung-Chih

    should be replaced or repaired and saves us quite a bit of money in the future," Chaio said. The tiny windmills could power remote sensors that monitor soil dryness in fields, saving water, energy The Future of Biogas A Renewable Resource Staff Writer Frontier of Energy Storage The Holy Grail Staff Writer

  9. 3/3/2014 Big ideas for tinywindmills at UTA | RenewablesBiz http://www.renewablesbiz.com/article/14/03/big-ideas-tiny-windmills-uta 1/3

    E-Print Network [OSTI]

    Chiao, Jung-Chih

    Energy Central E-Newsletters Recent News/Commentary Three Firms Win Solar Plant Tenders In Va. politics, renewable energy dwarfed by big utility ET Solar Builds Large Scale Solar Power Projects in UK Big ideas for tiny windmills at UTA DTE Energy selects SolarCurrents projects more news News Insights #12

  10. Channeling through Bent Crystals

    SciTech Connect (OSTI)

    Mack, Stephanie; /Ottawa U. /SLAC

    2012-09-07T23:59:59.000Z

    Bent crystals have demonstrated potential for use in beam collimation. A process called channeling is when accelerated particle beams are trapped by the nuclear potentials in the atomic planes within a crystal lattice. If the crystal is bent then the particles can follow the bending angle of the crystal. There are several different effects that are observed when particles travel through a bent crystal including dechanneling, volume capture, volume reflection and channeling. With a crystal placed at the edge of a particle beam, part of the fringe of the beam can be deflected away towards a detector or beam dump, thus helping collimate the beam. There is currently FORTRAN code by Igor Yazynin that has been used to model the passage of particles through a bent crystal. Using this code, the effects mentioned were explored for beam energy that would be seen at the Facility for Advanced Accelerator Experimental Tests (FACET) at a range of crystal orientations with respect to the incoming beam. After propagating 5 meters in vacuum space past the crystal the channeled particles were observed to separate from most of the beam with some noise due to dechanneled particles. Progressively smaller bending radii, with corresponding shorter crystal lengths, were compared and it was seen that multiple scattering decreases with the length of the crystal therefore allowing for cleaner detection of the channeled particles. The input beam was then modified and only a portion of the beam sent through the crystal. With the majority of the beam not affected by the crystal, most particles were not deflected and after propagation the channeled particles were seen to be deflected approximately 5mm. After a portion of the beam travels through the crystal, the entire beam was then sent through a quadrupole magnet, which increased the separation of the channeled particles from the remainder of the beam to a distance of around 20mm. A different code, which was developed at SLAC, was used to create an angular profile plot which was compared to what was produced by Yazynin's code for a beam with no multiple scattering. The results were comparable, with volume reflection and channeling effects observed and the range of crystal orientations at which volume reflection is seen was about 1 mrad in both simulations.

  11. Oscillations in glow discharges

    E-Print Network [OSTI]

    Prickett, Tom

    1950-01-01T23:59:59.000Z

    1950 CONTENTS Introduction ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1 I. Review of Plasma Oscillations in Gas Discharges ? . . 2 II. Review of Relaxation Processes in Gas Discharges ? . 13 III. Report of Laboratory Investigation... 179540 LIST OF FIGURES Figure Page 1. Sketch of Plasma Space in which Electrons are given Displacements in the X-direction ? ? ? ? ? ? 5 2* Early Circuit Arrangement of Discharge Study ? ? ? ? ? 19 3, Flow Diagram of the Experimental System...

  12. SINGLE CRYSTAL NEUTRON DIFFRACTION.

    SciTech Connect (OSTI)

    KOETZLE,T.F.

    2001-03-13T23:59:59.000Z

    Single-crystal neutron diffraction measures the elastic Bragg reflection intensities from crystals of a material, the structure of which is the subject of investigation. A single crystal is placed in a beam of neutrons produced at a nuclear reactor or at a proton accelerator-based spallation source. Single-crystal diffraction measurements are commonly made at thermal neutron beam energies, which correspond to neutron wavelengths in the neighborhood of 1 Angstrom. For high-resolution studies requiring shorter wavelengths (ca. 0.3-0.8 Angstroms), a pulsed spallation source or a high-temperature moderator (a ''hot source'') at a reactor may be used. When complex structures with large unit-cell repeats are under investigation, as is the case in structural biology, a cryogenic-temperature moderator (a ''cold source'') may be employed to obtain longer neutron wavelengths (ca. 4-10 Angstroms). A single-crystal neutron diffraction analysis will determine the crystal structure of the material, typically including its unit cell and space group, the positions of the atomic nuclei and their mean-square displacements, and relevant site occupancies. Because the neutron possesses a magnetic moment, the magnetic structure of the material can be determined as well, from the magnetic contribution to the Bragg intensities. This latter aspect falls beyond the scope of the present unit; for information on magnetic scattering of neutrons see Unit 14.3. Instruments for single-crystal diffraction (single-crystal diffractometers or SCDs) are generally available at the major neutron scattering center facilities. Beam time on many of these instruments is available through a proposal mechanism. A listing of neutron SCD instruments and their corresponding facility contacts is included in an appendix accompanying this unit.

  13. The Effect of Temperature and Composition on Spinel Concentration and Crystal Size in High-Level Waste Glass

    SciTech Connect (OSTI)

    Mika, M (.); Patek, M (.); Maixner, J (.); Randakova, S (.); Hrma, Pavel R. (BATTELLE (PACIFIC NW LAB)); Anibal Taboas, Rick Vanbrabant, Gary Benda.

    2001-01-01T23:59:59.000Z

    High-level radioactive wastes can be safely immobilized in alkali-aluminoborosilicate glass. To reduce the cost of the vitrification process, the waste loading should be maximized. This can be done by optimizing the process using mathematical modeling. The main objective of our work was to determine one of the necessary inputs for the mathematical model, which is the effect of temperature and composition on the concentration of spinel crystals and their size. We prepared six glasses with a different content of Li+, Na+, Mg2+, Ni2+, Cr3+, and SiIV and studied the effect of composition on the temperature dependence of spinel equilibrium concentration in glass by X-ray powder diffraction. The size of crystals was determined using optical microscopy. It was found that the temperature effect on spinel concentration significantly increased as the content of Ni2+ or Mg2+ in glass increased and slightly decreased as the content of Cr3+ increased and Li+ and Na+ content decreased. Both Ni2+ and Cr3+ acted as nucleating agents, producing a huge number of tiny spinel crystals ({approx}2 im). In particular, Ni2+ seems to very significantly facilitate spinel crystallization.

  14. Frequency doubling crystals

    DOE Patents [OSTI]

    Wang, Francis (Danville, CA); Velsko, Stephan P. (Livermore, CA)

    1989-01-01T23:59:59.000Z

    A systematic approach to the production of frequency conversion crystals is described in which a chiral molecule has attached to it a "harmonic generating unit" which contributes to the noncentrosymmetry of the molecule. Certain preferred embodiments of such harmonic generating units include carboxylate, guanadyly and imidazolyl units. Certain preferred crystals include L-arginine fluoride, deuterated L-arginine fluoride, L-arginine chloride monohydrate, L-arginine acetate, dithallium tartrate, ammonium N-acetyl valine, N-acetyl tyrosine and N-acetyl hydroxyproline. Chemical modifications of the chiral molecule, such as deuteration, halogenation and controlled counterion substitution are available to adapt the dispersive properties of a crystal in a particular wavelength region.

  15. Journal of Crystal Growth ] (

    E-Print Network [OSTI]

    ) at high pressure of CO2 (initial PCO2 ¼ 55 bar) and moderate to high temperature (30 and 90 1C) was used and the dissolved quantity of CO2 have a significant effect on the average particle size, specific surface areaJournal of Crystal Growth ] (

  16. Silicon crystal growing by oscillating crucible technique

    DOE Patents [OSTI]

    Schwuttke, G.H.; Kim, K.M.; Smetana, P.

    1983-08-03T23:59:59.000Z

    A process for growing silicon crystals from a molten melt comprising oscillating the container during crystal growth is disclosed.

  17. Oxynitrided Surface Layer Produced On Ti6Al4V Titanium Alloy Under Low Temperature Glow Discharge Conditions For Medical Applications

    SciTech Connect (OSTI)

    Wierzchon, T.; Ossowski, M.; Borowski, T. [Faculty of Materials Science and Engineering, Warsaw University of Technology, 141 Woloska Str, 02-507 Warsaw (Poland); Morgiel, J. [Institute of Metallurgy and Materials Science, Polish Academy of Science, 25 Reymonta Str, 30-059 Cracow (Poland); Czarnowska, E. [Department of Pathology, The Children's Memorial Health Institute, 20 Dzieci Polskich Av., 04-730 Warsaw (Poland)

    2011-01-17T23:59:59.000Z

    In spite that titanium oxides increase biocompatibility of titanium implants but their functional life is limited due to the problems arising from brittles and metalosis. Therefore technology, that allow to produce composite surface layer with controlled microstructure, chemical and phase composition and surface morphology on titanium alloy and eliminates the oxides disadvantages has been existing till now is searched. The requirements of titanium and its alloys implants can be fulfill by the low-temperature glow discharge assisted oxynitriding.The paper describes the surface layer of TiO{sub 2}+TiN+Ti{sub 2}N+{alpha}Ti(N) type produced at temperature 680 deg. C that preserves mechanical properties of titanium alloy Ti6Al4V. Characteristics of produced diffusion multi-phase surface layers in range of phase composition, microstructure (SEM, TEM, XRD) and its properties, such as frictional wear resistance are presented. The biological properties in dependency to the applied sterilization method are also analyzed.Properties of produced surface layers are discussed with reference to titanium alloy. The obtained data show that produced surface layers improves titanium alloy properties both frictional wear and biological. Preliminary in vitro examinations show good biocompatibility and antithrombogenic properties.

  18. Crystal face temperature determination means

    DOE Patents [OSTI]

    Nason, D.O.; Burger, A.

    1994-11-22T23:59:59.000Z

    An optically transparent furnace having a detection apparatus with a pedestal enclosed in an evacuated ampule for growing a crystal thereon is disclosed. Temperature differential is provided by a source heater, a base heater and a cold finger such that material migrates from a polycrystalline source material to grow the crystal. A quartz halogen lamp projects a collimated beam onto the crystal and a reflected beam is analyzed by a double monochromator and photomultiplier detection spectrometer and the detected peak position in the reflected energy spectrum of the reflected beam is interpreted to determine surface temperature of the crystal. 3 figs.

  19. Florida Nuclear Profile - Crystal River

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

    Crystal River1" "Unit","Summer capacity (mw)","Net generation (thousand mwh)","Summer capacity factor (percent)","Type","Commercial operation date","License expiration date"...

  20. crystal nickel a hree dimension

    E-Print Network [OSTI]

    Braun, Paul

    Zhenting 1 Department 2 Departmen ABSTRACT This pape crystal nickel a hree dimension photonic cryst polystyrene op silicon chips, volume fraction can be controlle nickel structure hen sacrificed volume fraction reports microm crystal structur or alumina she nickel microca microstructure further electrop volume

  1. Lamella settler crystallizer

    DOE Patents [OSTI]

    Maimoni, A.

    1990-12-18T23:59:59.000Z

    A crystallizer is described which incorporates a lamella settler and which is particularly applicable for use in batteries and power cells for electric vehicles or stationary applications. The lamella settler can be utilized for coarse particle separation or for agglomeration, and is particularly applicable to aluminum-air batteries or power cells for solving the hydrargillite (aluminum-hydroxide) removal problems from such batteries. This invention provides the advantages of very low energy consumption, turbulence, shear, cost and maintenance. Thus, due to the low shear and low turbulence of this invention, it is particularly effective in the control of aluminum hydroxide particle size distribution in the various sections of an aluminum-air system, as well as in other electrochemical systems requiring separation for phases of different densities. 3 figs.

  2. Lamella settler crystallizer

    DOE Patents [OSTI]

    Maimoni, Arturo (Orinda, CA)

    1990-01-01T23:59:59.000Z

    A crystallizer which incorporates a lamella settler and which is particularly applicable for use in batteries and power cells for electric vehicles or stationary applications. The lamella settler can be utilized for coarse particle separation or for agglomeration, and is particularly applicable to aluminum-air batteries or power cells for solving the hydrargillite (aluminum-hydroxide) removal problems from such batteries. This invention provides the advantages of very low energy consumption, turbulence, shear, cost and maintenance. Thus, due to the low shear and low turbulence of this invention, it is particularly effective in the control of aluminum hydroxide particle size distribution in the various sections of an aluminum-air system, as well as in other electrochemical systems requiring separation for phases of different densities.

  3. Frequency mixing crystal

    DOE Patents [OSTI]

    Ebbers, Christopher A. (Livermore, CA); Davis, Laura E. (Manteca, CA); Webb, Mark (Salida, CA)

    1992-01-01T23:59:59.000Z

    In a laser system for converting infrared laser light waves to visible light comprising a source of infrared laser light waves and means of harmoic generation associated therewith for production of light waves at integral multiples of the frequency of the original wave, the improvement of said means of harmonic generation comprising a crystal having the chemical formula X.sub.2 Y(NO.sub.3).sub.5 .multidot.2 nZ.sub.2 o wherein X is selected from the group consisting of Li, Na, K, Rb, Cs, and Tl; Y is selected from the group consisting of Sc, Y, La, Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In; Z is selected from the group consisting of H and D; and n ranges from 0 to 4.

  4. Crystal-Like geometric modeling

    E-Print Network [OSTI]

    Landreneau, Eric Benjamin

    2006-08-16T23:59:59.000Z

    faces, symmetry, and fractal geometry. The techniques have also been implemented in software, as a proof of concept. They are used in an interactive geometric modeling system, in which users can use these techniques to create crystal-like shapes...

  5. Arnold Schwarzenegger SINGLE CRYSTAL SILICON

    E-Print Network [OSTI]

    in this report. #12;ENERGY INNOVATIONS SMALL GRANT (EISG) PROGRAM INDEPENDENT ASSESSMENT REPORT (IAR) SINGLEArnold Schwarzenegger Governor SINGLE CRYSTAL SILICON SHEET GROWTH Prepared For: California Energy Commission Energy Innovations Small Grant Program Prepared By: Energy Materials Research

  6. Active materials in photonic crystals

    E-Print Network [OSTI]

    Bermel, Peter (Peter A.)

    2007-01-01T23:59:59.000Z

    I analyze new phenomena arising from embedding active materials inside of photonic crystal structures. These structures strongly modify the photonic local density of states (LDOS), leading to quantitative and qualitative ...

  7. Minimizing radiation damage in nonlinear optical crystals

    DOE Patents [OSTI]

    Cooke, D. Wayne (Santa Fe, NM); Bennett, Bryan L. (Los Alamos, NM); Cockroft, Nigel J. (Santa Fe, NM)

    1998-01-01T23:59:59.000Z

    Methods are disclosed for minimizing laser induced damage to nonlinear crystals, such as KTP crystals, involving various means for electrically grounding the crystals in order to diffuse electrical discharges within the crystals caused by the incident laser beam. In certain embodiments, electrically conductive material is deposited onto or into surfaces of the nonlinear crystals and the electrically conductive surfaces are connected to an electrical ground. To minimize electrical discharges on crystal surfaces that are not covered by the grounded electrically conductive material, a vacuum may be created around the nonlinear crystal.

  8. Minimizing radiation damage in nonlinear optical crystals

    DOE Patents [OSTI]

    Cooke, D.W.; Bennett, B.L.; Cockroft, N.J.

    1998-09-08T23:59:59.000Z

    Methods are disclosed for minimizing laser induced damage to nonlinear crystals, such as KTP crystals, involving various means for electrically grounding the crystals in order to diffuse electrical discharges within the crystals caused by the incident laser beam. In certain embodiments, electrically conductive material is deposited onto or into surfaces of the nonlinear crystals and the electrically conductive surfaces are connected to an electrical ground. To minimize electrical discharges on crystal surfaces that are not covered by the grounded electrically conductive material, a vacuum may be created around the nonlinear crystal. 5 figs.

  9. Crystal Potential Formula for the Calculation of Crystal Lattice Sums1 Don Steiger and Calvin Ahlbrandt

    E-Print Network [OSTI]

    Glaser, Rainer

    Crystal Potential Formula for the Calculation of Crystal Lattice Sums1 Don Steiger and Calvin; In Final Form: April 7, 1998 A new formula is derived for the determination of the potential energy of the central unit cell of a finite crystal; this formula is called the crystal potential formula. The crystal

  10. Adaptive Liquid Crystal Windows

    SciTech Connect (OSTI)

    Taheri, Bahman; Bodnar, Volodymyr

    2011-12-31T23:59:59.000Z

    Energy consumption by private and commercial sectors in the U.S. has steadily grown over the last decade. The uncertainty in future availability of imported oil, on which the energy consumption relies strongly, resulted in a dramatic increase in the cost of energy. About 20% of this consumption are used to heat and cool houses and commercial buildings. To reduce dependence on the foreign oil and cut down emission of greenhouse gases, it is necessary to eliminate losses and reduce total energy consumption by buildings. To achieve this goal it is necessary to redefine the role of the conventional windows. At a minimum, windows should stop being a source for energy loss. Ideally, windows should become a source of energy, providing net gain to reduce energy used to heat and cool homes. It is possible to have a net energy gain from a window if its light transmission can be dynamically altered, ideally electronically without the need of operator assistance, providing optimal control of the solar gain that varies with season and climate in the U.S. In addition, the window must not require power from the building for operation. Resolution of this problem is a societal challenge and of national interest and will have a broad global impact. For this purpose, the year-round, allclimate window solution to provide an electronically variable solar heat gain coefficient (SHGC) with a wide dynamic range is needed. AlphaMicron, Inc. (AMI) developed and manufactured 1ft × 1ft prototype panels for the world’s first auto-adjusting Adaptive Liquid Crystal Windows (ALCWs) that can operate from sunlight without the need for external power source and demonstrate an electronically adjustable SHGC. This novel windows are based on AlphaMicron’s patented e-Tint® technology, a guesthost liquid crystal system implemented on flexible, optically clear plastic films. This technology is suitable both for OEM and aftermarket (retro-fitting) lamination to new and existing windows. Low level of power consumption by ALCWs allows for on-board power electronics for automatic matching of transmission through windows to varying climate conditions without drawing the power from the power grid. ALCWs are capable of transmitting more sunlight in winters to assist in heating and less sunlight in summers to minimize overheating. As such, they can change the window from being a source of energy loss to a source of energy gain. In addition, the scalable AMI’s roll-to-roll process, proved by making 1ft × 1ftALCW prototype panels, allows for cost-effective production of large-scale window panels along with capability to change easily their color and shape. In addition to architectural glazing in houses and commercial buildings, ALCWs can be used in other applications where control of sunlight is needed, such as green houses, used by commercial produce growers and botanical gardens, cars, aircrafts, etc.

  11. automated crystal screening: Topics by E-print Network

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

    high crystallization rates and the production of diffraction-quality crystals. microfluidics Quake, Stephen R. 5 Data Mining Crystallization Databases: Knowledge-Based...

  12. Precision Crystal Calorimeters in High Energy Physics

    ScienceCinema (OSTI)

    Ren-Yuan Zhu

    2010-01-08T23:59:59.000Z

    Precision crystal calorimeters traditionally play an important role in high energy physics experiments. In the last two decades, it faces a challenge to maintain its precision in a hostile radiation environment. This paper reviews the performance of crystal calorimeters constructed for high energy physics experiments and the progress achieved in understanding crystal?s radiation damage as well as in developing high quality scintillating crystals for particle physics. Potential applications of new generation scintillating crystals of high density and high light yield, such as LSO and LYSO, in particle physics experiments is also discussed.

  13. Crystallization during processing of nuclear waste glass

    SciTech Connect (OSTI)

    Hrma, Pavel R.

    2010-12-01T23:59:59.000Z

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glassmaking are reviewed.

  14. Crystal-field effects in fluoride crystals for optical refrigeration

    SciTech Connect (OSTI)

    Hehlen, Markus P [Los Alamos National Laboratory

    2010-01-01T23:59:59.000Z

    The field of optical refrigeration of rare-earth-doped solids has recently seen an important breakthrough. The cooling of a YLiF{sub 4} (YLF) crystal doped with 5 mol% Yb3+ to 155 K by Seletskiy et al [NPhot] has surpassed the lowest temperatures ({approx}170 K for {approx}100 mW cooling capacity) that are practical with commercial multi-stage thermoelectric coolers (TEC) [Glaister]. This record performance has advanced laser cooling into an application relevant regime and has put first practical optical cryocoolers within reach. The result is also relevant from a material perspective since for the first time, an Yb3+-doped crystal has outperformed an Yb3+-doped glass. The record temperature of 208 K was held by the Yb3+-doped fluorozirconate glass ZBLAN. Advanced purification and glass fabrication methods currently under development are expected to also advance ZBLAN:Yb3+ to sub-TEC temperatures. However, recent achievements with YLF:Yb3+ illustrate that crystalline materials may have two potentially game-changing advantajes over glassy materials. First, the crystalline environment reduces the inhomogeneous broadening of the Yb3+ electronic transitions as compared to a glassy matrix. The respective sharpening of the crystal-field transitions increases the peak absorption cross section at the laser excitation wavelength and allows for more efficient pumping of the Yb3+ ions, particularly at low temperatures. Second, many detrimental impurities present in the starting materials tend to be excluded from the crystal during its slow growth process, in contrast to a glass where all impurities present in the starting materials are included in the glass when it is formed by temperature quenching a melt. The ultra high purity required for laser cooling materials [PRB] therefore may be easier to realize in crystals than in glasses. Laser cooling occurs by laser excitation of a rare-earth ion followed by anti-Stokes luminescence. Each such laser-cooling cycle extracts thermal energy from the solid and carries it away as high-entropy light, thereby cooling the material. In the ideal case, the respective laser-cooling power is given by the pump wavelength ({lambda}{sub p}), the mean fluorescence wavelength ({bar {lambda}}{sub L}), and the absorption coefficient (a{sub r}) of the pumped transition. These quantities are solely determined by crystal field interactions. On one hand, a large crystal-field splitting offers a favorably large difference of {lambda}{sub p} - {bar {lambda}}{sub L} and thus a high cooling efficiency {eta}{sub cool} = ({lambda}{sub p} - {bar {lambda}}{sub L})/{bar {lambda}}{sub L}. On the other hand, a small crystal-field splitting offers a high thermal population (n{sub i}) of the initial state of the pumped transition, giving a high pump absorption coefficient and thus high laser cooling power, particularly at low temperatures. A quantitative description of crystal-field interactions is therefore critical to the understanding and optimization of optical refrigeration. In the case of Yb3+ as the laser cooling ion, however, development of a crystal-field model is met with substantial difficulties. First, Yb3+ has only two 4/multiplets, {sup 2}F{sub 7/2} and {sup 2}F{sub 5/2}, which lead to at most 7 crystal-field levels. This makes it difficult, and in some cases impossible, to evaluate the crystal-field Hamiltonian, which has at least 4 parameters for any Yb3+ point symmety lower than cubic. Second, {sup 2}F{sub 7/2}{leftrightarrow}{sup 2}F{sub 5/2} transitions exhibit an exceptionally strong electron-phonon coupling compared to 4f transitions of other rare earths. This makes it difficult to distinguish electronic from vibronic transitions in the absorption and luminescence spectra and to reliably identify the crystal-field levels. Yb3+ crystal-field splittings reported in the literature should thus generally be viewed with caution. This paper explores the effects of crystal-field interactions on the laser cooling performance of Yb3+-doped fluoride crystals. It is shown that the total crystal-field splitting o

  15. Manufacturing method of photonic crystal

    DOE Patents [OSTI]

    Park, In Sung; Lee, Tae Ho; Ahn, Jin Ho; Biswas, Rana; Constant, Kristen P.; Ho, Kai-Ming; Lee, Jae-Hwang

    2013-01-29T23:59:59.000Z

    A manufacturing method of a photonic crystal is provided. In the method, a high-refractive-index material is conformally deposited on an exposed portion of a periodic template composed of a low-refractive-index material by an atomic layer deposition process so that a difference in refractive indices or dielectric constants between the template and adjacent air becomes greater, which makes it possible to form a three-dimensional photonic crystal having a superior photonic bandgap. Herein, the three-dimensional structure may be prepared by a layer-by-layer method.

  16. Crystallization in High-Level Waste Glasses

    SciTech Connect (OSTI)

    Hrma, Pavel R. (BATTELLE (PACIFIC NW LAB)); Dane R Spearing, Gary L Smith, SK Sundaram

    2002-01-01T23:59:59.000Z

    This review outlines important aspects of crystallization in HLW glasses, such as equilibrium, nucleation, growth, and dissolution. The impact of crystallization on continuous melters and the chemical durability of high-level waste glass are briefly discussed.

  17. Potash Crystallization Lynn Batten1

    E-Print Network [OSTI]

    Tsatsomeros, Michael

    fertilizer and industrial chemical, from saturated brines. Typically, hot brine at about 100 C is cooled, knowledge of the spatial distribution of the chemical supersaturation state of the brine would help to improve the process control objectives: · Define conditions for crystal growth · Minimize occluded brine

  18. Robotic CCD microscope for enhanced crystal recognition

    DOE Patents [OSTI]

    Segelke, Brent W. (San Ramon, CA); Toppani, Dominique (Livermore, CA)

    2007-11-06T23:59:59.000Z

    A robotic CCD microscope and procedures to automate crystal recognition. The robotic CCD microscope and procedures enables more accurate crystal recognition, leading to fewer false negative and fewer false positives, and enable detection of smaller crystals compared to other methods available today.

  19. Crystal structure refinement with SHELXL

    SciTech Connect (OSTI)

    Sheldrick, George M., E-mail: gsheldr@shelx.uni-ac.gwdg.de [Department of Structural Chemistry, Georg-August Universität Göttingen, Tammannstraße 4, Göttingen 37077 (Germany)

    2015-01-01T23:59:59.000Z

    New features added to the refinement program SHELXL since 2008 are described and explained. The improvements in the crystal structure refinement program SHELXL have been closely coupled with the development and increasing importance of the CIF (Crystallographic Information Framework) format for validating and archiving crystal structures. An important simplification is that now only one file in CIF format (for convenience, referred to simply as ‘a CIF’) containing embedded reflection data and SHELXL instructions is needed for a complete structure archive; the program SHREDCIF can be used to extract the .hkl and .ins files required for further refinement with SHELXL. Recent developments in SHELXL facilitate refinement against neutron diffraction data, the treatment of H atoms, the determination of absolute structure, the input of partial structure factors and the refinement of twinned and disordered structures. SHELXL is available free to academics for the Windows, Linux and Mac OS X operating systems, and is particularly suitable for multiple-core processors.

  20. Commercial Application of Freeze Crystallization

    E-Print Network [OSTI]

    Gorgol, R. G.

    COMMERCIAL APPLICATION OF FREEZE CRYSTALLIZATION ROBERT G. GORGOL, MARKETING MANAGER, HPD INCORPORATED, NAPERVILLE, ILLINOIS ABSTRACT Industrial usc of frcezing for componcnt purification and separation is well understood, but commercial... of purification, but they did understand the water they obtained from ice was potable. RECENT APPLICATIONS Scientists have understood the basic mechanism of the freezing phase change for many years. ID an effort to harness the power of this phenomena...

  1. Abstract crystals Department of Mathematics

    E-Print Network [OSTI]

    Ram, Arun

    is a normal crystal define a bijection si : B B by sib = ~f wti(b) i b, if wti(b) 0, ~e -wti(b) i b, if wti, b2 B2} with wti(b1 b2) = wti(b1) + wti(b2), i(b1 b2) = max{i(b1), i(b2) - wt(b1), i }, i(b1 b2

  2. Bent core liquid crystal elastomers

    SciTech Connect (OSTI)

    Verduzco, R.; DiMasi, E.; Luchette, P.; Ho Hong, S.; Harden, J.; Palffy-Muhoray, P.; Kilbey II, S.M.; Sprunt, S.; Gleeson, G.T. Jakli, A.

    2010-07-28T23:59:59.000Z

    Liquid crystal (LC) elastomers with bent-core side-groups incorporate the properties of bent-core liquid crystals in a flexible and self-supporting polymer network. Bent-core liquid crystal elastomers (BCEs) with uniform alignment were prepared by attaching a reactive bent-core LC to poly(hydrogenmethylsiloxane) and crosslinking with a divinyl crosslinker. Phase behavior studies indicate a nematic phase over a wide temperature range that approaches room temperature, and thermoelastic measurements show that these BCEs can reversibly change their length by more than a factor of two upon heating and cooling. Small-angle X-ray scattering studies reveal multiple, broad low-angle peaks consistent with short-range smectic C order of the bent-core side groups. A comparison of these patterns with predictions of a Landau model for short-range smectic C order shows that the length scale for smectic ordering in BCEs is similar to that seen in pure bent-core LCs. The combination of rubber elasticity and smectic ordering of the bent-core side groups suggests that BCEs may be promising materials for sensing, actuating, and other advanced applications.

  3. Insights into the crystal chemistry of Earth materials rendered by electron density distributions: Pauling's rules revisited

    SciTech Connect (OSTI)

    Gibbs, Gerald V.; Ross, Nancy L.; Cox, David F.; Rosso, Kevin M.

    2014-05-20T23:59:59.000Z

    Pauling's first two rules are examined in terms of the accumulation of the electron density between bonded pairs of atoms for a relatively large number of oxide and silicate crystals and siloxane molecules. The distribution of the electron density shows that the radius of the oxygen atom is not fixed, but that it actually decreases systematically from ~1.40 Å to ~ 0.65 Å as the polarizing power and the electronegativity of the bonded metal atoms increase and the distribution of the O atom is progressively polarized and contracted along the bond vectors by the impact of the bonded interactions. The contractions result in an aspherical oxygen atom that displays as many different bonded “radii” as it has bonded interactions. The bonded radii for the metal atoms match the Shannon and Prewitt ionic radii for the more electropositive atoms like potassium and sodium, but they are systematically larger for the more electronegative atoms like aluminum, silicon and phosphorous. Pauling's first rule is based on the assumption that the radius of the oxide anion is fixed and that the radii of the cations are such that radius sum of the spherical oxide anion and a cation necessarily equals the separation between the cation-anion bonded pair with the coordination number of the cation being determined by the ratio of the radii of the cation and anion. In the case of the bonded radii, the sum of the bonded radii for the metal atoms and the oxide anion necessarily equals the bond lengths by virtue of the way that the bonded radii were determined in the partitioning of the electron density along the bond path into metal and O atom parts. But, the radius ratio for the O and M atoms is an unsatisfactory rule for determining the coordination number of the metal atom inasmuch as a bonded O atom is not, in general, spherical, and its size varies substantially along its bonded directions. But by counting the number of bond paths that radiate from a bonded atom, the coordination number of the atom is determined uniquely independent of the asphericity and sizes of the atom. A power law connection established between the bond lengths and bond strengths for crystals and molecules is mirrored by a comparable power law connection between bond length and the accumulation of the electron density between bonded pairs of atoms, a connection that is consistent with Pauling's electroneutrality postulate that the charges of the atoms in an oxide are negligibly small. The connection indicates that a one-to-one correspondence exists between the accumulation between a pair of bonded atoms and the Pauling bond strength for M-O bonded interaction for all atoms of the periodic table. The connection provides a common basis for understanding the success of the manifold applications that have been made with the bond valence theory model together with the modeling of crystal structures, chemical zoning, leaching and cation transport in batteries and the like. We believe that the wide spread applications of the model in mineralogy and material science owes much of its success to the direct connection between bond strength and the quantum mechanical observable, the electron density distribution. Comparable power law expressions established for the bonded interactions for both crystals and molecules support Pauling's assertion that his second rule has significance for molecules as well as for crystals. A simple expression is found that provides a one to one connection between the accumulation of the electron density between bonded M and O atoms and the Pauling bond strength for all M atoms of the periodic table with ~ 95 % of the variation of the bond strength being explained in terms of a linear dependence on the accumulated electron density. Compelling evidence is presented that supports the argument that the Si-O bonded interactions for tiny siloxane molecules and silicate crystals are chemically equivalent.

  4. A nucleon in a tiny box

    E-Print Network [OSTI]

    Bedaque, P F; Rupak, G; Bedaque, Paulo F; Griesshammer, Harald W; Rupak, Gautam

    2004-01-01T23:59:59.000Z

    We use Chiral Perturbation Theory techniques to compute the nucleon mass-shift due to finite volume and temperature effects. Our results are valid up to next-to-leading order in the "$\\eps$-r{\\'e}gime" ($mL\\sim m\\beta\\ll 1$) as well as in the "$p$-r{\\'e}gime" ($mL\\sim m\\beta\\gg 1$). Based on the two leading orders, we discuss the convergence of the expansion as a function of the lattice size and quark masses and find that only for particular $\\beta/L$ ratios does the expansion seem to converge. This result can be used to extrapolate lattice results obtained from lattice sizes smaller than the pion cloud, avoiding the numerical simulation of physics under theoretical control.

  5. Meet the trillions of tiny allies that

    E-Print Network [OSTI]

    Dennett, Daniel

    & A n WALKABLE TOWNS n IS GLUTEN-FREE FOR ME? MAGA ZINE OF THE GER ALD J. AND DOROTHY R. FRIEDMAN SCHOOL- cer and exercise study, for example, took several years and entailed developing a complicated search any good? By Julie Flaherty 14 If You Build It, They Will Walk Thoughtful town planning can get

  6. Chemistry in Motion: Tiny Synthetic Motors

    E-Print Network [OSTI]

    Peter H. Colberg; Shang Yik Reigh; Bryan Robertson; Raymond Kapral

    2014-11-03T23:59:59.000Z

    In this Account, we describe how synthetic motors that operate by self-diffusiophoresis make use of a self-generated concentration gradient to drive motor motion. A description of propulsion by self-diffusiophoresis is presented for Janus particle motors comprising catalytic and noncatalytic faces. The properties of the dynamics of chemically powered motors are illustrated by presenting the results of particle-based simulations of sphere-dimer motors constructed from linked catalytic and noncatalytic spheres. The geometries of both Janus and sphere-dimer motors with asymmetric catalytic activity support the formation of concentration gradients around the motors. Because directed motion can occur only when the system is not in equilibrium, the nature of the environment and the role it plays in motor dynamics are described. Rotational Brownian motion also acts to limit directed motion, and it has especially strong effects for very small motors. We address the following question: how small can motors be and still exhibit effects due to propulsion, even if only to enhance diffusion? Synthetic motors have the potential to transform the manner in which chemical dynamical processes are carried out for a wide range of applications.

  7. Crystallization and functionality of inorganic materials

    SciTech Connect (OSTI)

    Xue, Dongfeng, E-mail: dongfeng@ciac.jl.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China) [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Li, Keyan [School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China)] [School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Liu, Jun [Key Laboratory of Low Dimensional Materials and Application Technology, Ministry of Education, Faculty of Materials, Optoelectronics and Physics, Xiangtan University, 411105 (China)] [Key Laboratory of Low Dimensional Materials and Application Technology, Ministry of Education, Faculty of Materials, Optoelectronics and Physics, Xiangtan University, 411105 (China); Sun, Congting; Chen, Kunfeng [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China) [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China)

    2012-10-15T23:59:59.000Z

    In this article, we briefly summarized our recent work on the studies of crystallization and functionality of inorganic materials. On the basis of the chemical bonding theory of single crystal growth, we can quantitatively simulate Cu{sub 2}O crystallization processes in solution system. We also kinetically controlled Cu{sub 2}O crystallization process in the reduction solution route. Lithium ion battery and supercapacitor performances of some oxides such as Co{sub 3}O{sub 4} and MnO{sub 2} were shown to elucidate the important effect of crystallization on functionality of inorganic materials. This work encourages us to create novel functionalities through the study of crystallization of inorganic materials, which warrants more chances in the field of functional materials.

  8. Phonon manipulation with phononic crystals.

    SciTech Connect (OSTI)

    Kim Bongsang; Hopkins, Patrick Edward; Leseman, Zayd C.; Goettler, Drew F.; Su, Mehmet F. (University of New Mexico, Albuquerque, NM); El-Kady, Ihab Fathy; Reinke, Charles M.; Olsson, Roy H., III

    2012-01-01T23:59:59.000Z

    In this work, we demonstrated engineered modification of propagation of thermal phonons, i.e. at THz frequencies, using phononic crystals. This work combined theoretical work at Sandia National Laboratories, the University of New Mexico, the University of Colorado Boulder, and Carnegie Mellon University; the MESA fabrication facilities at Sandia; and the microfabrication facilities at UNM to produce world-leading control of phonon propagation in silicon at frequencies up to 3 THz. These efforts culminated in a dramatic reduction in the thermal conductivity of silicon using phononic crystals by a factor of almost 30 as compared with the bulk value, and about 6 as compared with an unpatterned slab of the same thickness. This work represents a revolutionary advance in the engineering of thermoelectric materials for optimal, high-ZT performance. We have demonstrated the significant reduction of the thermal conductivity of silicon using phononic crystal structuring using MEMS-compatible fabrication techniques and in a planar platform that is amenable to integration with typical microelectronic systems. The measured reduction in thermal conductivity as compared to bulk silicon was about a factor of 20 in the cross-plane direction [26], and a factor of 6 in the in-plane direction. Since the electrical conductivity was only reduced by a corresponding factor of about 3 due to the removal of conductive material (i.e., porosity), and the Seebeck coefficient should remain constant as an intrinsic material property, this corresponds to an effective enhancement in ZT by a factor of 2. Given the number of papers in literature devoted to only a small, incremental change in ZT, the ability to boost the ZT of a material by a factor of 2 simply by reducing thermal conductivity is groundbreaking. The results in this work were obtained using silicon, a material that has benefitted from enormous interest in the microelectronics industry and that has a fairly large thermoelectric power factor. In addition, the techniques and scientific understanding developed in the research can be applied to a wide range of materials, with the caveat that the thermal conductivity of such a material be dominated by phonon, rather than electron, transport. In particular, this includes several thermoelectric materials with attractive properties at elevated temperatures (i.e., greater than room temperature), such as silicon germanium and silicon carbide. It is reasonable that phononic crystal patterning could be used for high-temperature thermoelectric devices using such materials, with applications in energy scavenging via waste-heat recovery and thermoelectric cooling for high-performance microelectronic circuits. The only part of the ZT picture missing in this work was the experimental measurement of the Seebeck coefficient of our phononic crystal devices. While a first-order approximation indicates that the Seebeck coefficient should not change significantly from that of bulk silicon, we were not able to actually verify this assumption within the timeframe of the project. Additionally, with regards to future high-temperature applications of this technology, we plan to measure the thermal conductivity reduction factor of our phononic crystals as elevated temperatures to confirm that it does not diminish, given that the nominal thermal conductivity of most semiconductors, including silicon, decreases with temperature above room temperature. We hope to have the opportunity to address these concerns and further advance the state-of-the-art of thermoelectric materials in future projects.

  9. Singular Limits in Polymer Stabilized Liquid Crystals

    E-Print Network [OSTI]

    1910-31-00T23:59:59.000Z

    We investigate equilibrium configurations for a polymer stabilized liquid crys- tal material ... eling the cross section of the liquid crystal-polymer fiber composite.

  10. Photonic crystals for high temperature applications

    E-Print Network [OSTI]

    Yeng, Yi Xiang

    2014-01-01T23:59:59.000Z

    This thesis focuses on the design, optimization, fabrication, and experimental realization of metallic photonic crystals (MPhCs) for high temperature applications, for instance thermophotovoltaic (TPV) energy conversion ...

  11. Controlled growth of semiconductor crystals

    DOE Patents [OSTI]

    Bourret-Courchesne, E.D.

    1992-07-21T23:59:59.000Z

    A method is disclosed for growth of III-V, II-VI and related semiconductor single crystals that suppresses random nucleation and sticking of the semiconductor melt at the crucible walls. Small pieces of an oxide of boron B[sub x]O[sub y] are dispersed throughout the comminuted solid semiconductor charge in the crucible, with the oxide of boron preferably having water content of at least 600 ppm. The crucible temperature is first raised to a temperature greater than the melt temperature T[sub m1] of the oxide of boron (T[sub m1]=723 K for boron oxide B[sub 2]O[sub 3]), and the oxide of boron is allowed to melt and form a reasonably uniform liquid layer between the crucible walls and bottom surfaces and the still-solid semiconductor charge. The temperature is then raised to approximately the melt temperature T[sub m2] of the semiconductor charge material, and crystal growth proceeds by a liquid encapsulated, vertical gradient freeze process. About half of the crystals grown have a dislocation density of less than 1000/cm[sup 2]. If the oxide of boron has water content less than 600 ppm, the crucible material should include boron nitride, a layer of the inner surface of the crucible should be oxidized before the oxide of boron in the crucible charge is melted, and the sum of thicknesses of the solid boron oxide layer and liquid boron oxide layer should be at least 50 [mu]m. 7 figs.

  12. Controlled growth of semiconductor crystals

    DOE Patents [OSTI]

    Bourret-Courchesne, Edith D. (Richmond, CA)

    1992-01-01T23:59:59.000Z

    A method for growth of III-V, II-VI and related semiconductor single crystals that suppresses random nucleation and sticking of the semiconductor melt at the crucible walls. Small pieces of an oxide of boron B.sub.x O.sub.y are dispersed throughout the comminuted solid semiconductor charge in the crucible, with the oxide of boron preferably having water content of at least 600 ppm. The crucible temperature is first raised to a temperature greater than the melt temperature T.sub.m1 of the oxide of boron (T.sub.m1 =723.degree. K. for boron oxide B.sub.2 O.sub.3), and the oxide of boron is allowed to melt and form a reasonably uniform liquid layer between the crucible walls and bottom surfaces and the still-solid semiconductor charge. The temperature is then raised to approximately the melt temperature T.sub.m2 of the semiconductor charge material, and crystal growth proceeds by a liquid encapsulated, vertical gradient freeze process. About half of the crystals grown have a dislocation density of less than 1000/cm.sup.2. If the oxide of boron has water content less than 600 ppm, the crucible material should include boron nitride, a layer of the inner surface of the crucible should be oxidized before the oxide of boron in the crucible charge is melted, and the sum of thicknesses of the solid boron oxide layer and liquid boron oxide layer should be at least 50 .mu.m.

  13. Crystal Systems | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnual Siteof Energy 2,AUDIT REPORTEnergy Offshore Place:WindOilCowal Wind Energy LtdCrystal

  14. Journal of Crystal Growth 250 (2003) 499515 Induction time in crystallization of gas hydrates

    E-Print Network [OSTI]

    Firoozabadi, Abbas

    2003-01-01T23:59:59.000Z

    Journal of Crystal Growth 250 (2003) 499­515 Induction time in crystallization of gas hydrates Dimo. Kern Abstract The kinetics of the initial stage of crystallization of one-component gas hydrates of gas consumed are determined. Expressions are derived for the supersaturation dependence of the hydrate

  15. A Complete Microfluidic Screening Platform for Rational Protein Crystallization

    E-Print Network [OSTI]

    Hansen, Carl L.

    A Complete Microfluidic Screening Platform for Rational Protein Crystallization Billy T. C. Lau integration, and low reagent consumption, microfluidic devices have emerged as viable technologies for protein crystallization. Current microfluidic crystallization technologies have focused on two separate strategies: one

  16. Transverse acoustic actuation of Ni-Mn-Ga single crystals

    E-Print Network [OSTI]

    Simon, Jesse Matthew

    2007-01-01T23:59:59.000Z

    Two methods for the transverse acoustic actuation of {110}-cut Ni-Mn-Ga single crystals are discussed. In this actuation mode, crystals are used that have the {110}- type twinning planes parallel to the base of the crystal. ...

  17. Coherent multilayer crystals and method of making

    DOE Patents [OSTI]

    Schuller, I.K.; Falco, C.M.

    1980-10-30T23:59:59.000Z

    A new material is described consisting of a coherent multilayer crystal of two or more elements where each layer is composed of a single element. Each layer may vary in thickness from about 2 A to 2500 A. The multilayer crystals are prepared by sputter deposition under conditions which slow the sputtered atoms to near substrate temperatures before they contact the substrate.

  18. Growth Of Oriented Crystals At Polymerized Membranes

    DOE Patents [OSTI]

    Charych, Deborah H. (Albany, CA), Berman, Amir (Ben-Shiva, IL)

    2000-01-25T23:59:59.000Z

    The present invention relates to methods and compositions for the growth and alignment of crystals at biopolymeric films. The methods and compositions of the present invention provide means to generate a variety of dense crystalline ceramic films, with totally aligned crystals, at low temperatures and pressures, suitable for use with polymer and plastic substrates.

  19. General recipe for designing photonic crystal cavities

    E-Print Network [OSTI]

    Vuckovic, Jelena

    . Yariv and P. Yeh, Optical Waves in Crystals (Wiley and Sons, 2003). 13. A. Badolato, K. Hennessy, M and links 1. S. Johnson, S. Fan, A. Mekis, and J. Joannopoulos, "Multipole-cancellation mechanism for high. Vuckovi´c, M. Loncar, H. Mabuchi, and A. Scherer, "Design of photonic crystal microcavities for cavity QED

  20. Ames Lab 101: Single Crystal Growth

    ScienceCinema (OSTI)

    Schlagel, Deborah

    2014-06-04T23:59:59.000Z

    Ames Laboratory scientist Deborah Schlagel talks about the Lab's research in growing single crystals of various metals and alloys. The single crystal samples are vital to researchers' understanding of the characteristics of a materials and what gives these materials their particular properties.

  1. Liquid crystal device and method thereof

    DOE Patents [OSTI]

    Shiyanovskii, Sergij V; Gu, Mingxia; Lavrentovich, Oleg D

    2012-10-23T23:59:59.000Z

    The invention provides a liquid crystal device and method thereof. Subsequent to applying a first electrical voltage on a liquid crystal to induce a reorientation of the liquid crystal, a second electrical voltage with proper polarity is applied on the liquid crystal to assist the relaxation of the reorientation that was induced by the first electrical voltage. The "switch-off" phase of the liquid crystal can therefore be accelerated or temporally shortened, and the device can exhibit better performance such as fast response to on/off signals. The invention can be widely used LCD, LC shutter, LC lens, spatial light modulator, telecommunication device, tunable filter, beam steering device, and electrically driven LC device, among others.

  2. Analysis of Crystal Lattice Deformation by Ion Channeling. |...

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

    Crystal Lattice Deformation by Ion Channeling. Analysis of Crystal Lattice Deformation by Ion Channeling. Abstract: A model of dislocations has been developed for the use in Monte...

  3. Microfluidic systems for continuous crystallization of small organic molecules

    E-Print Network [OSTI]

    Sultana, Mahmooda

    2010-01-01T23:59:59.000Z

    This thesis presents one of the first demonstrations of continuous crystallization in microfluidic devices, and illustrates their use for various applications related to crystallization of small organic molecules. ...

  4. antiferroelectric liquid crystals: Topics by E-print Network

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

    of phases in antiferroelectric liquid crystals Condensed Matter (arXiv) Summary: The free energy of antiferroelectric liquid crystal which takes into account polar order...

  5. antiferroelectric liquid crystal: Topics by E-print Network

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

    of phases in antiferroelectric liquid crystals Condensed Matter (arXiv) Summary: The free energy of antiferroelectric liquid crystal which takes into account polar order...

  6. Corrosion of Partially Crystallized Glasses

    SciTech Connect (OSTI)

    Hrma, Pavel R.; Riley, Brian J.; Vienna, John D.

    2002-05-21T23:59:59.000Z

    Using existing data on corrosion of partially crystallized, simulated, high-level waste glasses, coefficients were introduced to evaluate the cumulative influence of secondary effects, such as residual stresses or concentration gradients on product consistency test response. As compared to predictions based solely on residual glass composition effects, the results showed that cristobalite, eucryptite, and nepheline had a higher-than-predicted impact on glass corrosion, while the effects of baddeleyite, hematite, calcium-zirconium silicate, and zircon were close to those predicted. The effects of acmite and lithium silicate were opposite to those expected based on their compositions. The analysis revealed important limitations of the databases currently available. Better understanding of corrosion phenomena will require quantitative composition data, microscopic characterization of pristine and corroded surfaces, and long-term tests with glass coupons or monoliths.

  7. Novel photonic crystal cavities and related structures.

    SciTech Connect (OSTI)

    Luk, Ting Shan

    2007-11-01T23:59:59.000Z

    The key accomplishment of this project is to achieve a much more in-depth understanding of the thermal emission physics of metallic photonic crystal through theoretical modeling and experimental measurements. An improved transfer matrix technique was developed to enable incorporation of complex dielectric function. Together with microscopic theory describing emitter radiative and non-radiative relaxation dynamics, a non-equilibrium thermal emission model is developed. Finally, experimental methodology was developed to measure absolute emissivity of photonic crystal at high temperatures with accuracy of +/-2%. Accurate emissivity measurements allow us to validate the procedure to treat the effect of the photonic crystal substrate.

  8. Cold neutron scattering in imperfect deuterium crystals

    E-Print Network [OSTI]

    Andrzej Adamczak

    2010-12-10T23:59:59.000Z

    The differential cross sections for cold neutron scattering in mosaic deuterium crystals have been calculated for various target temperatures. The theoretical results are compared with the recent experimental data for the neutron wavelengths $\\lambda\\approx$~1--9~\\AA. It is shown that the structures of observed Bragg peaks can be explained by the mosaic spread of about $3^{\\circ}$ and contributions from a~limited number of crystal orientations. Such a~crystal structure should be also taken into account in ultracold neutron upscattering due to the coherent phonon annihilation in solid deuterium.

  9. Shearing Flows in Liquid Crystal Models

    E-Print Network [OSTI]

    Dorn, Timothy

    2012-05-31T23:59:59.000Z

    . The director field is the realization of local averaging to de- scribe the natural state in a nematic liquid crystal, Figure 1.1. For any natural alignment of the liquid crystal, n?, one prescribes that W (n?,?n?) = 0. Since the director field is used... derivative of h by the formula D Dt h(t,x) = ?h? t +(u · ~?)h. The acceleration is of the liquid crystal material through the point x is given by a(t,x) = Du Dt . Following the classical approach one assumes that for every open subset Wt ??, trav- eling along...

  10. Crystal growth under external electric fields

    SciTech Connect (OSTI)

    Uda, Satoshi; Koizumi, Haruhiko; Nozawa, Jun; Fujiwara, Kozo [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan)

    2014-10-06T23:59:59.000Z

    This is a review article concerning the crystal growth under external electric fields that has been studied in our lab for the past 10 years. An external field is applied electrostatically either through an electrically insulating phase or a direct injection of an electric current to the solid-interface-liquid. The former changes the chemical potential of both solid and liquid and controls the phase relationship while the latter modifies the transport and partitioning of ionic solutes in the oxide melt during crystallization and changes the solute distribution in the crystal.

  11. NMR and NQR parameters of ethanol crystal

    E-Print Network [OSTI]

    Milinkovic, M

    2012-01-01T23:59:59.000Z

    Electric field gradients and chemical shielding tensors of the stable monoclinic crystal phase of ethanol are computed. The projector-augmented wave (PAW) and gauge-including projector-augmented wave (GIPAW) models in the periodic plane-wave density functional theory are used. The crystal data from X-ray measurements, as well as the structures where either all atomic, or only hydrogen atom positions are optimized in the density functional theory are analyzed. These structural models are also studied by including the semi-empirical Van der Waals correction to the density functional theory. Infrared spectra of these five crystal models are calculated.

  12. Changes in mobility of plastic crystal ethanol during its transformation into the monoclinic crystal state

    SciTech Connect (OSTI)

    Sanz, Alejandro, E-mail: alejandro.sanz@csic.es; Nogales, Aurora; Ezquerra, Tiberio A. [Instituto de Estructura de la Materia, IEM-CSIC, Serrano 121, 28006 Madrid (Spain)] [Instituto de Estructura de la Materia, IEM-CSIC, Serrano 121, 28006 Madrid (Spain); Puente-Orench, Inés [Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France) [Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France); Instituto de Ciencia de Materiales de Aragón, ICMA-CSIC, Pedro Cerbuna 12, 50009 Zaragoza (Spain); Jiménez-Ruiz, Mónica [Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France)] [Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France)

    2014-02-07T23:59:59.000Z

    Transformation of deuterated ethanol from the plastic crystal phase into the monoclinic one is investigated by means of a singular setup combining simultaneously dielectric spectroscopy with neutron diffraction. We postulate that a dynamic transition from plastic crystal to supercooled liquid-like configuration through a deep reorganization of the hydrogen-bonding network must take place as a previous step of the crystallization process. Once these precursor regions are formed, subsequent crystalline nucleation and growth develop with time.

  13. Semiconductor liquid crystal composition and methods for making the same

    DOE Patents [OSTI]

    Alivisatos, A. Paul; Li, Liang-shi

    2005-04-26T23:59:59.000Z

    Semiconductor liquid crystal compositions and methods for making such compositions are disclosed. One embodiment of the invention is directed to a liquid crystal composition including a solvent and semiconductor particles in the solvent. The solvent and the semiconductor particles are in an effective amount in the liquid crystal composition to form a liquid crystal phase.

  14. Styrene Purification and Recovery Using Freeze Crystallization

    E-Print Network [OSTI]

    Heist, J. A.; Wrobel, P. J.

    Lab tests have demonstrated the ability to separate styrene from ABS and SAN plastics wastes by cooling the waste until the styrene begins to crystallize. The same process that recovers styrene from these wastes can be used to purify styrene...

  15. Nanoparticle-chiral nematic liquid crystal composites

    E-Print Network [OSTI]

    Payne, Jeffrey C. (Jeffrey Christopher), 1981-

    2006-01-01T23:59:59.000Z

    The advancement of the fabrication of a one-dimensional photonic crystal without time-reversal and space-inversion symmetries was pursued. Theoretical studies predict that such a system would exhibit unusual optical ...

  16. Thermophysical parameters of the LBO crystal

    SciTech Connect (OSTI)

    Grechin, Sergei G [Scientific-Research Institute of Radioelectronics and Laser Technology at the N.E. Bauman Moscow State Technical University, Moscow (Russian Federation); Zuev, A V; Fokin, A S [All-Russian Scientific Research Institute of Aviation Materials, Moscow (Russian Federation); Kokh, Aleksandr E [V.S.Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation); Moiseev, N V; Popov, Petr A; Sidorov, Aleksei A [Acad. I. G. Petrovskii Bryansk State University, Bryansk (Russian Federation)

    2010-08-27T23:59:59.000Z

    The thermophysical parameters (linear thermal expansion coefficients, thermal conductivities, and heat capacity) of the lithium triborate (LBO) crystal are measured and compared with previously published data. (nonlinear-optics phenomena)

  17. Crystallization of carbon tetrachloride in confined geometries

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Crystallization of carbon tetrachloride in confined geometries Adil Meziane1 , Jean-Pierre E 40 71 08 #12;2 Abstract The thermal behaviour of carbon tetrachloride confined in silica gels

  18. Electrically driven photonic crystal nanocavity devices

    E-Print Network [OSTI]

    Shambat, Gary; Petykiewicz, Jan; Mayer, Marie A; Majumdar, Arka; Sarmiento, Tomas; Harris, James; Haller, Eugene E; Vuckovic, Jelena

    2012-01-01T23:59:59.000Z

    Interest in photonic crystal nanocavities is fueled by advances in device performance, particularly in the development of low-threshold laser sources. Effective electrical control of high performance photonic crystal lasers has thus far remained elusive due to the complexities associated with current injection into cavities. A fabrication procedure for electrically pumping photonic crystal membrane devices using a lateral p-i-n junction has been developed and is described in this work. We have demonstrated electrically pumped lasing in our junctions with a threshold of 181 nA at 50K - the lowest threshold ever demonstrated in an electrically pumped laser. At room temperature we find that our devices behave as single-mode light-emitting diodes (LEDs), which when directly modulated, have an ultrafast electrical response up to 10 GHz corresponding to less than 1 fJ/bit energy operation - the lowest for any optical transmitter. In addition, we have demonstrated electrical pumping of photonic crystal nanobeam LEDs...

  19. Method for solid state crystal growth

    DOE Patents [OSTI]

    Nolas, George S.; Beekman, Matthew K.

    2013-04-09T23:59:59.000Z

    A novel method for high quality crystal growth of intermetallic clathrates is presented. The synthesis of high quality pure phase crystals has been complicated by the simultaneous formation of both clathrate type-I and clathrate type-II structures. It was found that selective, phase pure, single-crystal growth of type-I and type-II clathrates can be achieved by maintaining sufficient partial pressure of a chemical constituent during slow, controlled deprivation of the chemical constituent from the primary reactant. The chemical constituent is slowly removed from the primary reactant by the reaction of the chemical constituent vapor with a secondary reactant, spatially separated from the primary reactant, in a closed volume under uniaxial pressure and heat to form the single phase pure crystals.

  20. The Crystal Method: Asteroseismology of BPM 37093

    E-Print Network [OSTI]

    T. S. Metcalfe; M. H. Montgomery; A. Kanaan

    2004-08-19T23:59:59.000Z

    More than 40 years have passed since Ed Salpeter and others predicted that the carbon/oxygen cores of the coolest white dwarf stars in our Galaxy will theoretically crystallize. This effect has a dramatic impact on the calculated ages of cool white dwarfs, but until recently we have had no way of testing the theory. In 1992, pulsations were discovered in the massive potentially crystallized white dwarf BPM 37093, and in 1999 the theoretical effects of crystallization on the pulsation modes were determined. Observations from two Whole Earth Telescope campaigns in 1998 and 1999, combined with a new model-fitting method using a genetic algorithm, are now giving us the first glimpse inside of a crystallized star.

  1. Neutron detection with single crystal organic scintillators

    SciTech Connect (OSTI)

    Zaitseva, N; Newby, J; Hamel, S; Carman, L; Faust, M; Lordi, V; Cherepy, N; Stoeffl, W; Payne, S

    2009-07-15T23:59:59.000Z

    Detection of high-energy neutrons in the presence of gamma radiation background utilizes pulse-shape discrimination (PSD) phenomena in organics studied previously only with limited number of materials, mostly liquid scintillators and single crystal stilbene. The current paper presents the results obtained with broader varieties of luminescent organic single crystals. The studies involve experimental tools of crystal growth and material characterization in combination with the advanced computer modeling, with the final goal of better understanding the relevance between the nature of the organic materials and their PSD properties. Special consideration is given to the factors that may diminish or even completely obscure the PSD properties in scintillating crystals. Among such factors are molecular and crystallographic structures that determine exchange coupling and exciton mobility in organic materials and the impurity effect discussed on the examples of trans-stilbene, bibenzyl, 9,10-diphenylanthracene and diphenylacetylene.

  2. Imaging with Spherically Bent Crystals or Reflectors

    SciTech Connect (OSTI)

    Bitter, M; Hill, K W; Scott, S; Ince-Cushman, A; Reinke, M; Podpaly, Y; Rice, J E; Beiersdorfer, P

    2010-06-01T23:59:59.000Z

    This paper consists of two parts: Part I describes the working principle of a recently developed x-ray imaging crystal spectrometer, where the astigmatism of spherically bent crystals is being used with advantage to record spatially resolved spectra of highly charged ions for Doppler measurements of the ion-temperature and toroidal plasmarotation- velocity profiles in tokamak plasmas. This type of spectrometer was thoroughly tested on NSTX and Alcator C-Mod, and its concept was recently adopted for the design of the ITER crystal spectrometers. Part II describes imaging schemes, where the astigmatism has been eliminated by the use of matched pairs of spherically bent crystals or reflectors. These imaging schemes are applicable over a wide range of the electromagnetic radiation, which includes microwaves, visible light, EUV radiation, and x-rays. Potential applications with EUV radiation and x-rays are the diagnosis of laserproduced plasmas, imaging of biological samples with synchrotron radiation, and lithography.

  3. Enhancement of crystal homogeneity of protein crystals under application of an external alternating current electric field

    SciTech Connect (OSTI)

    Koizumi, H.; Uda, S.; Fujiwara, K.; Nozawa, J. [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577 (Japan); Tachibana, M. [Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama, 236-0027 (Japan); Kojima, K. [Department of Education, Yokohama Soei University, 1 Miho-tyou, Midori-ku, Yokohama, 226-0015 (Japan)

    2014-10-06T23:59:59.000Z

    X-ray diffraction rocking-curve measurements were performed on tetragonal hen egg white (HEW) lysozyme crystals grown with and without the application of an external alternating current (AC) electric field. The crystal quality was assessed by the full width at half maximum (FWHM) value for each rocking curve. For two-dimensional maps of the FWHMs measured on the 440 and the 12 12 0 reflection, the crystal homogeneity was improved under application of an external electric field at 1 MHz, compared with that without. In particular, the significant improvement of the crystal homogeneity was observed for the 12 12 0 reflection.

  4. Method for reducing energy losses in laser crystals

    DOE Patents [OSTI]

    Atherton, L.J.; DeYoreo, J.J.; Roberts, D.H.

    1992-03-24T23:59:59.000Z

    A process for reducing energy losses in crystals is disclosed which comprises: a. heating a crystal to a temperature sufficiently high as to cause dissolution of microscopic inclusions into the crystal, thereby converting said inclusions into point-defects, and b. maintaining said crystal at a given temperature for a period of time sufficient to cause said point-defects to diffuse out of said crystal. Also disclosed are crystals treated by the process, and lasers utilizing the crystals as a source of light. 12 figs.

  5. Demixing cascades in cluster crystals

    E-Print Network [OSTI]

    Nigel B. Wilding; Peter Sollich

    2014-07-14T23:59:59.000Z

    In a cluster crystal, each lattice site is occupied by multiple soft-core particles. As the number density is increased at zero temperature, a `cascade' of isostructural phase transitions can occur between states whose site occupancy differs by unity. For low but finite temperature, each of these transitions terminates in a critical point. Using tailored Monte Carlo simulation techniques we have studied such demixing cascades in systems of soft particles interacting via potentials of the generalized exponential form $u(r)=\\epsilon\\exp[-(r/\\sigma)^n]$. We have estimated the critical parameters of the first few transitions in the cascade as a function of the softness parameter $n$. The critical temperature and pressure exhibit non-monotonic behaviour as $n$ is varied, although the critical chemical potential remains monotonic. The trends for the pressure and chemical potential are confirmed by cell model calculations at zero temperature. As $n\\to 2^+$, all the transitions that we have observed are preempted by melting although we cannot rule out that clustering transitions survive at high density.

  6. Photonic Crystal Laser-Driven Accelerator Structures

    SciTech Connect (OSTI)

    Cowan, B.; /SLAC

    2005-09-19T23:59:59.000Z

    We discuss simulated photonic crystal structure designs for laser-driven particle acceleration, focusing on three-dimensional planar structures based on the so-called ''woodpile'' lattice. We demonstrate guiding of a speed-of-light accelerating mode by a defect in the photonic crystal lattice and discuss the properties of this mode. We also discuss particle beam dynamics in the structure, presenting a novel method for focusing the beam. In addition we describe some potential coupling methods for the structure.

  7. Liquid crystal variable retarders in atomic scattering

    SciTech Connect (OSTI)

    Furst, J.E.; Yu, D.H.; Hayes, P.A.; DSouza, C.M.; Williams, J.F. [Physics Department, Centre for Atomic, Molecular, and Surface Physics, The University of Western Australia, Nedlands. WA. 6907 (Australia)] [Physics Department, Centre for Atomic, Molecular, and Surface Physics, The University of Western Australia, Nedlands. WA. 6907 (Australia)

    1996-11-01T23:59:59.000Z

    The applications of liquid crystal variable retarders in the production of spin-polarized electrons and in the determination of the polarization of optical radiation from atoms excited by polarized electrons are discussed. The advantages of using liquid crystal variable retarders in the measurement of Stokes parameters are insensitivity to the incident photon direction, large transmission diameter, variable retardation over large wavelength range without mechanical movement, and {ital in} {ital situ} calibration. {copyright} {ital 1996 American Institute of Physics.}

  8. Surface Energy,Surface Energy, Surface Tension & Shape of CrystalsSurface Tension & Shape of Crystals

    E-Print Network [OSTI]

    Subramaniam, Anandh

    Surface Energy,Surface Energy, Surface Tension & Shape of CrystalsSurface Tension & Shape of shapes of crystals are important: (i) growth shape and (ii) equilibrium shape Surface/interface energy surfaces. The joining of two phases creates an interface. (Two orientations of the same crystalline phase

  9. Development of single crystal filaments. Final report

    SciTech Connect (OSTI)

    Milewski, J.V.; Shoultz, R.A.; Bourque-McConnell, M.M.

    1995-04-01T23:59:59.000Z

    The program just completed addresses a route to a more efficient longer-lasting electric light bulb filament. All current filaments for light bulbs are metallic in nature. They are subject to embrittlement with age (large grain growth) and relatively high vapor pressures which limits their operating temperature. There is evidence which suggests advantages to using high temperature refractory single crystal fibers as a filament for a light bulb. These refractory materials may include materials such as hafnium or tantalum carbide which have melting points about 500{degrees}C higher than tungsten. Another advantage is that single crystal fibers have a very high degree of crystalline perfection with very few voids and dislocations. Without these imperfections, the atomic mobility at high temperatures is highly restricted. Thus single crystal fibers are very stable at high temperature and will last longer. The efficiencies result from running these single crystal ceramic fiber filaments at higher temperatures and the higher emissivity of the carbide filaments compared to tungsten. The amount of visible light is proportional to the 4the power of the temperature thus a 500{degrees}C higher operating give about a 3-fold increase in radiation in the visible range. The program accomplishments can be summarized as follows: (1) Single crystal fibers of JfC sufficient crystal quality for light bulb filament applications were made. (2) The HfC fiber furnace growth chamber, power control and data collection system was developed for the laboratory scale plant. (3) method for mounting and apparatuses for testing the single crystal fiber filaments were developed and built.

  10. Crystal Chemistry of Th in Fluorapatite

    SciTech Connect (OSTI)

    Y Luo; J Rakovan; Y Tang; M Lupulescu; J Hughes; Y Pan

    2011-12-31T23:59:59.000Z

    Through the complementary use of single-crystal X-ray diffraction and X-ray absorption spectroscopy, we present in this paper the first direct results on the site occupancy of thorium in the fluorapatite structure and the structural distortion created by its substitution. Structure refinements based on single-crystal X-ray diffraction data from synthetic Th-doped fluorapatite indicates that Th substitutes almost exclusively in the M2 site. A single-crystal X-ray study of natural fluorapatite from Mineville, New York, also indicated that substituting heavy scatterers (including Th) are concentrated in the apatite M2 site, but definitive site assignments of specific elements were not possible. Extended X-ray absorption fine-structure spectroscopy (EXAFS) was used to probe the local structure of Th in the synthetic fluorapatite (single-crystal form) with a Th concentration of roughly 20000 ppm, as well as Th in the natural Mineville fluorapatite (powder form) with a Th concentration of {approx}2000 ppm. The EXAFS fitting results also indicate that Th partitions into the M2 site and yield a {approx}0.05-0.08 {angstrom} decrease of average M2-O bond distances associated with local structure distortions that are not obtainable from single-crystal X-ray diffraction studies.

  11. Charge transfer reactions in nematic liquid crystals

    SciTech Connect (OSTI)

    Wiederrecht, G.P. [Argonne National Lab., IL (United States). Chemistry Div.; Wasielewski, M.R. [Argonne National Lab., IL (United States). Chemistry Div.; [Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry; Galili, T.; Levanon, H. [Hebrew Univ. of Jerusalem (Israel). Dept. of Physical Chemistry

    1998-07-01T23:59:59.000Z

    Ultrafast transient absorption studies of intramolecular photoinduced charge separation and thermal charge recombination were carried out on a molecule consisting of a 4-(N-pyrrolidino)naphthalene-1,8-imide donor (PNI) covalently attached to a pyromellitimide acceptor (PI) dissolved in the liquid crystal 4{prime}-(n-pentyl)-4-cyanobiphenyl (5CB). The temperature dependencies of the charge separation and recombination rates were obtained at temperatures above the nematic-isotropic phase transition of 5CB, where ordered microdomains exist and scattering of visible light by these domains is absent. The authors show that excited state charge separation is dominated by molecular reorientation of 5CB perpendicular to the director within the liquid crystal microdomains. They also show that charge recombination is adiabatic and is controlled by the comparatively slow collective reorientation of the liquid crystal microdomains relative to the orientation of PNI{sup +}-PI{sup {minus}}. They also report the results of time resolved electron paramagnetic resonance (TREPR) studies of photoinduced charge separation in a series of supramolecular compounds dissolved in oriented liquid crystal solvents. These studies permit the determination of the radical pair energy levels as the solvent reorganization energy increases from the low temperature crystalline phase, through the soft glass phase, to the nematic phase of the liquid crystal.

  12. Science & Research Highlights | Advanced Photon Source

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

    crystals that glow different colors may be the missing ingredient for white light-emitting diode lighting that illuminates homes and offices as effectively as natural sunlight....

  13. Science Highlights 2013 | Advanced Photon Source

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

    crystals that glow different colors may be the missing ingredient for white light-emitting diode lighting that illuminates homes and offices as effectively as natural sunlight....

  14. Nano-crystal growth in cordierite glass ceramics studied with X-ray scattering

    E-Print Network [OSTI]

    Bras, Wim

    2010-01-01T23:59:59.000Z

    Nano-crystal growth in cordierite glass ceramics studiedmatrix in which crystalline nano-crystals are embedded. Bysample the Cr containing spinel nano crystals. In these SEM

  15. Quantum Calabi-Yau and Classical Crystals

    E-Print Network [OSTI]

    Andrei Okounkov; Nikolai Reshetikhin; Cumrun Vafa

    2003-11-11T23:59:59.000Z

    We propose a new duality involving topological strings in the limit of large string coupling constant. The dual is described in terms of a classical statistical mechanical model of crystal melting, where the temperature is inverse of the string coupling constant. The crystal is a discretization of the toric base of the Calabi-Yau with lattice length $g_s$. As a strong evidence for this duality we recover the topological vertex in terms of the statistical mechanical probability distribution for crystal melting. We also propose a more general duality involving the dimer problem on periodic lattices and topological A-model string on arbitrary local toric threefolds. The $(p,q)$ 5-brane web, dual to Calabi-Yau, gets identified with the transition regions of rigid dimer configurations.

  16. Ultrasonically assisted deposition of colloidal crystals

    SciTech Connect (OSTI)

    Wollmann, Sabine, E-mail: sabine.wollmann@griffithuni.edu.au [Lehrstuhl für Experimentalphysik 1 and Augsburg Centre for Innovative Technologies (ACIT), Universität Augsburg, 86159 Augsburg (Germany); Centre for Quantum Dynamics, Griffith University, Brisbane 4111 (Australia); Patel, Raj B. [Centre for Quantum Dynamics, Griffith University, Brisbane 4111 (Australia); Wixforth, Achim; Krenner, Hubert J. [Lehrstuhl für Experimentalphysik 1 and Augsburg Centre for Innovative Technologies (ACIT), Universität Augsburg, 86159 Augsburg (Germany); Nanosystems Initiative Munich (NIM), Schellingstr. 4, 80779 München (Germany)

    2014-07-21T23:59:59.000Z

    Colloidal particles are a versatile physical system which have found uses across a range of applications such as the simulation of crystal kinetics, etch masks for fabrication, and the formation of photonic band-gap structures. Utilization of colloidal particles often requires a means to produce highly ordered, periodic structures. One approach is the use of surface acoustic waves (SAWs) to direct the self-assembly of colloidal particles. Previous demonstrations using standing SAWs were shown to be limited in terms of crystal size and dimensionality. Here, we report a technique to improve the spatial alignment of colloidal particles using traveling SAWs. Through control of the radio frequency power, which drives the SAW, we demonstrate enhanced quality and dimensionality of the crystal growth. We show that this technique can be applied to a range of particle sizes in the ?m-regime and may hold potential for particles in the sub-?m-regime.

  17. Density functional theory for carbon dioxide crystal

    SciTech Connect (OSTI)

    Chang, Yiwen; Mi, Jianguo, E-mail: mijg@mail.buct.edu.cn; Zhong, Chongli [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China)

    2014-05-28T23:59:59.000Z

    We present a density functional approach to describe the solid?liquid phase transition, interfacial and crystal structure, and properties of polyatomic CO{sub 2}. Unlike previous phase field crystal model or density functional theory, which are derived from the second order direct correlation function, the present density functional approach is based on the fundamental measure theory for hard-sphere repulsion in solid. More importantly, the contributions of enthalpic interactions due to the dispersive attractions and of entropic interactions arising from the molecular architecture are integrated in the density functional model. Using the theoretical model, the predicted liquid and solid densities of CO{sub 2} at equilibrium triple point are in good agreement with the experimental values. Based on the structure of crystal-liquid interfaces in different planes, the corresponding interfacial tensions are predicted. Their respective accuracies need to be tested.

  18. Anisotropic wave propagation in nematic liquid crystals

    E-Print Network [OSTI]

    Paolo Biscari; Antonio DiCarlo; Stefano S. Turzi

    2014-05-10T23:59:59.000Z

    Despite the fact that quantitative experimental data have been available for more than forty years now, nematoacoustics still poses intriguing theoretical and experimental problems. In this paper, we prove that the main observed features of acoustic wave propagation through a nematic liquid crystal cell -- namely, the anisotropy of sound velocity and its frequency dependence -- may be plausibly explained by a first-gradient continuum theory characterized by a hyperelastic anisotropic response from an evolving relaxed configuration. We compare and contrast our proposal with a competing theory where the liquid crystal is modeled as an isotropically compressible, anisotropic second-gradient fluid.

  19. Interface control and snow crystal growth

    E-Print Network [OSTI]

    Jessica Li; Laura P. Schaposnik

    2015-05-08T23:59:59.000Z

    The growth of snow crystals is dependent on the temperature and saturation of the environment. In the case of dendrites, Reiter's local two-dimensional model provides a realistic approach to the study of dendrite growth. In this paper we obtain a new geometric rule that incorporates interface control, a basic mechanism of crystallization that is not taken into account in the original Reiter's model. By defining two new variables, growth latency and growth direction, our improved model gives a realistic model not only for dendrite but also for plate forms.

  20. Seismic Crystals And Earthquake Shield Application

    E-Print Network [OSTI]

    B. Baykant Alagoz; Serkan Alagoz

    2009-05-15T23:59:59.000Z

    We theoretically demonstrate that earthquake shield made of seismic crystal can damp down surface waves, which are the most destructive type for constructions. In the paper, seismic crystal is introduced in aspect of band gaps (Stop band) and some design concepts for earthquake and tsunami shielding were discussed in theoretical manner. We observed in our FDTD based 2D elastic wave simulations that proposed earthquake shield could provide about 0.5 reductions in magnitude of surface wave on the Richter scale. This reduction rate in magnitude can considerably reduce destructions in the case of earthquake.

  1. A Benchmark Construction of Positron Crystal Undulator

    E-Print Network [OSTI]

    Tikhomirov, Victor V

    2015-01-01T23:59:59.000Z

    Optimization of a positron crystal undulator (CU) is addressed. The ways to assure both the maximum intensity and minimum spectral width of positron CU radiation are outlined. We claim that the minimum CU spectrum width of 3 -- 4% is reached at the positron energies of a few GeV and that the optimal bending radius of crystals planes in CU ranges from 3 to 5 critical bending radii for channeled particles. Following suggested approach a benchmark positron CU construction is devised and its functioning is illustrated using the simulation method widely tested by experimental data.

  2. Simulation of the hard-sphere crystal–melt interface

    E-Print Network [OSTI]

    Davidchack, Ruslan L.; Laird, Brian Bostian

    1998-06-01T23:59:59.000Z

    of coexisting crystal- and fluidlike domains that are quite mobile on the time scale of the simulation. We also observe the creation and propagation of vacancies into the bulk crystal....

  3. New Crystal Structures Lift Fog around Protein Folding

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

    New Crystal Structures Lift Fog around Protein Folding New Crystal Structures Lift Fog around Protein Folding Print Wednesday, 25 July 2012 00:00 Nature's proteins set a high bar...

  4. Two-dimensional Photonic Crystals Fabricated by Nanoimprint Lithography

    E-Print Network [OSTI]

    Chen, A.

    We report on the process parameters of nanoimprint lithography (NIL) for the fabrication of two-dimensional (2-D) photonic crystals. The nickel mould with 2-D photonic crystal patterns covering the area up to 20mm² is ...

  5. Thin magnetic crystals are path to ferromagnetic graphene | ornl...

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

    Thin magnetic crystals are path to ferromagnetic graphene January 23, 2015 The crystal structure of CrI3 includes hexagonal nets formed by Cr atoms (blue) with magnetic moments...

  6. Engineering light using large area photonic crystal devices

    E-Print Network [OSTI]

    Tandon, Sheila (Sheila N.), 1978-

    2005-01-01T23:59:59.000Z

    Photonic crystals are fabricated structures composed of a periodic arrangement of materials with differing indices of refraction. This research has focused on the realization of two distinct photonic crystal structures in ...

  7. Experimental studies of melting and crystallization processes in planetary interiors

    E-Print Network [OSTI]

    Krawczynski, Michael James

    2011-01-01T23:59:59.000Z

    Melting and crystallization processes on the Earth and Moon are explored in this thesis, and the topics of melt generation, transport, and crystallization are discussed in three distinct geologic environments: the Moon's ...

  8. Coupled mode theory for photonic crystal cavity-waveguide interaction

    E-Print Network [OSTI]

    Vuckovic, Jelena

    nanocavity in a two-dimensional photonic crystal," Nature 425, 944­947 (2003) 16. A. Yariv. Optical in a two- dimensional photonic-crystal slab," App. Phys. Lett. 83, 407­409 (2003) 5. T. Asano et al. "A

  9. A World's Top-10 X-ray Crystal Structure

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

    A World's Top-10 X-ray Crystal Structure October 7, 2014 Bookmark and Share Philip Coppens An x-ray crystal structure solved by Philip Coppens has been chosen as one of the world's...

  10. Nepheline crystallization in boron-rich alumino-silicate glasses...

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

    Nepheline crystallization in boron-rich alumino-silicate glasses as investigated by multi-nuclear NMR, Raman, & Mö Nepheline crystallization in boron-rich alumino-silicate...

  11. Computer-aided rational solvent selection for pharmaceutical crystallization

    E-Print Network [OSTI]

    Chen, Jie, Ph. D. Massachusetts Institute of Technology

    2010-01-01T23:59:59.000Z

    Solvents play an important role in crystallization, a commonly used separation and purification technique in the pharmaceutical, chemical and food industries. They affect crystal properties such as particle size distribution, ...

  12. Morphological control of silicalite-1 crystals using microemulsion mediated growth

    E-Print Network [OSTI]

    Lee, Seung Ju

    2005-11-01T23:59:59.000Z

    mediated synthesis, it is concluded that the surfactant??silicate interactions are primarily responsible for the modulation of crystal morphology observed. The results indicate that surfactant adsorption on the growing crystal surface, not the confined...

  13. 5.841 Crystal Structure Refinement, Fall 2006

    E-Print Network [OSTI]

    Mueller, Peter

    This course in crystal structure refinement examines the practical aspects of crystal structure determination from data collection strategies to data reduction and basic and advanced refinement problems of organic and ...

  14. 5.067 Crystal Structure Refinement, Fall 2007

    E-Print Network [OSTI]

    Mueller, Peter

    This course in crystal structure refinement examines the practical aspects of crystal structure determination from data collection strategies to data reduction and basic and advanced refinement problems of organic and ...

  15. Anomalous phenomena and spectral tailoring in photonic crystals

    E-Print Network [OSTI]

    Ghebrebrhan, Michael

    2010-01-01T23:59:59.000Z

    Photonic crystals are recently discovered meta-materials whose optical properties arise from periodic refractive index variations. In this thesis I examine various aspects of photonic crystals including a self-assembled ...

  16. Designing the properties of dispersion-flattened photonic crystal fibers

    E-Print Network [OSTI]

    Fernández de Córdoba, Pedro

    crystal fibers," Electron. Lett. 35, 63-64 (1999). 4. P. J. Bennet, T. M. Monro, and D. J. Richardson

  17. Crystal Engineering Morphosynthesis of Rhombododecahedral Silver

    E-Print Network [OSTI]

    Qi, Limin

    of metal nanoparticles; examples include silver nanorods,[17] nanoprisms,[18] and nano- cubes.[19] Hollow of primary building blocks into hollow spheres or cages,[9­14] as these hollow structures with nanometer, and as photonic crystals.[15] In most cases, however, only spherical hollow structures have been obtained either

  18. Crystal fields in UO2 - revisited

    SciTech Connect (OSTI)

    Nakotte, Heinz [Los Alamos National Laboratory; Rajatram, R [NMSU/UNIV OF N.C.; Kern, S [COLORADO STATE UNIV; Mcqueeney, R J [AMES LAB; Lander, G H [EUROPEAN COMMISIONS, JRC; Robinson, R A [BRAGG INSTITUTE

    2009-01-01T23:59:59.000Z

    We performed inelastic neutron scattering (INS) in order to re-investigate the crystal-field ground state and the level splitting in UO{sub 2}. Previous INS studies on UO{sub 2} by Amorelli et al. [Physical Review B 15, 1989, 1856] uncovered four excitations at low temperatures in the 150-180 meV range. Considering the dipole-allowed transitions, only three of these transitions could be explained by the published crystal-field model. Our INS results on a different UO{sub 2} sample revealed that the unaccounted peak at about 180 meV is a spurious one, and thus not intrinsic to UO{sub 2}. In good agreement with Amoretti's results, we corroborated that the ground-state of UO{sub 2} is the {Lambda}{sub 5} triplet, and we computed that the fourth- and six-order crystal field parameters are V{sub 4} = -116 meV and V{sub 6} = 26 meV, respectively. We also studied the INS response of the non-magnetic U{sub 0.4}Th{sub 0.6}O{sub 2}. The splitting for this thorium-doped compound is similar to the one of UO{sub 2}, which orders antiferromagnetically at low temperatures. Therefore, we can conclude that magnetic interactions only weakly perturb the energy level splitting, which is dominated by strong crystal fields.

  19. Synthetic thermoelectric materials comprising phononic crystals

    DOE Patents [OSTI]

    El-Kady, Ihab F; Olsson, Roy H; Hopkins, Patrick; Reinke, Charles; Kim, Bongsang

    2013-08-13T23:59:59.000Z

    Synthetic thermoelectric materials comprising phononic crystals can simultaneously have a large Seebeck coefficient, high electrical conductivity, and low thermal conductivity. Such synthetic thermoelectric materials can enable improved thermoelectric devices, such as thermoelectric generators and coolers, with improved performance. Such synthetic thermoelectric materials and devices can be fabricated using techniques that are compatible with standard microelectronics.

  20. Nanobeam photonic crystal cavity quantum dot laser

    E-Print Network [OSTI]

    Vuckovic, Jelena

    1. O. Painter, R. K. Lee, A. Scherer, A. Yariv, J. D. O'Brien, P. D. Dapkus, and I. Kim, "Two, J. Vuckovi´c, and A. Scherer, "Planar photonic crystal nanolasers (I): Porous cavity lasers," IEICE coupling factor," Phys. Rev. B 75, 195313 (2007). 9. S. Strauf, K. Hennessy, M. T. Rakher, Y.-S. Choi, A

  1. Nanostructured Calcite Single Crystals with Gyroid Morphologies

    E-Print Network [OSTI]

    Steiner, Ullrich

    , the unconstrained crystallization of calcium carbonate (CaCO3) leads to the precipitation of brittle rhombohedral of these factors on CaCO3 nucleation and growth, which can also lead to control over polymorph and orientation. It is becoming increas- ingly apparent that the formation of crystalline CaCO3 is often preceded by an amorphous

  2. Discotic Liquid Crystals and Polymersomes: Molecule Goniometers

    E-Print Network [OSTI]

    Chang, Ya-Wen

    2012-10-19T23:59:59.000Z

    ................................ 6 1.2.4 Discotic Liquid Crystals ................................................... 9 1.2.5 Microfluidics .................................................................... 11 1.3. Dissertation Outline... ........................................................... 15 2.1.2 Di-block Copolymers, Lipids, and Particles .................... 15 2.1.3 Reactive Fluorophores ...................................................... 16 2.1.4 Surface Functionalization Chemicals...

  3. Ytterbium- and neodymium-doped vanadate laser hose crystals having the apatite crystal structure

    DOE Patents [OSTI]

    Payne, Stephen A. (Castro Valley, CA); Kway, Wayne L. (Fremont, CA); DeLoach, Laura D. (Manteca, CA); Krupke, William F. (Pleasanton, CA); Chai, Bruce H. T. (Oviedo, FL)

    1994-01-01T23:59:59.000Z

    Yb.sup.3+ and Nd.sup.3+ doped Sr.sub.5 (VO.sub.4).sub.3 F crystals serve as useful infrared laser media that exhibit low thresholds of oscillation and high slope efficiencies, and can be grown with high optical quality. These laser media possess unusually high absorption and emission cross sections, which provide the crystals with the ability to generate greater gain for a given amount of pump power. Many related crystals such as Sr.sub.5 (VO.sub.4).sub.3 F crystals doped with other rare earths, transition metals, or actinides, as well as the many structural analogs of Sr.sub.5 (VO.sub.4).sub.3 F, where the Sr.sup.2+ and F.sup.- ions are replaced by related chemical species, have similar properties.

  4. Ytterbium- and neodymium-doped vanadate laser hose crystals having the apatite crystal structure

    DOE Patents [OSTI]

    Payne, S.A.; Kway, W.L.; DeLoach, L.D.; Krupke, W.F.; Chai, B.H.T.

    1994-08-23T23:59:59.000Z

    Yb[sup 3+] and Nd[sup 3+] doped Sr[sub 5](VO[sub 4])[sub 3]F crystals serve as useful infrared laser media that exhibit low thresholds of oscillation and high slope efficiencies, and can be grown with high optical quality. These laser media possess unusually high absorption and emission cross sections, which provide the crystals with the ability to generate greater gain for a given amount of pump power. Many related crystals such as Sr[sub 5](VO[sub 4])[sub 3]F crystals doped with other rare earths, transition metals, or actinides, as well as the many structural analogs of Sr[sub 5](VO[sub 4])[sub 3]F, where the Sr[sup 2+] and F[sup [minus

  5. Statistical Analysis of Crystallization Database Links Protein Physico-Chemical Features with Crystallization Mechanisms

    E-Print Network [OSTI]

    Fusco, Diana

    X-ray crystallography is the predominant method for obtaining atomic-scale information about biological macromolecules. Despite the success of the technique, obtaining well diffracting crystals still critically limits going ...

  6. Liquid crystals and Q-tensors The free energy

    E-Print Network [OSTI]

    Segatti, Antonio

    Liquid crystals and Q-tensors The free energy A temperature-dependent model Mathematical results #12;Liquid crystals and Q-tensors The free energy A temperature-dependent model Mathematical results, Non-isothermal nematic liquid crystals flows with the Ball-Majumdar free energy, Ann. Mat. Pura Appl

  7. Giant Plasticity of a Quantum Crystal Ariel Haziot,1

    E-Print Network [OSTI]

    Balibar, Sébastien

    Giant Plasticity of a Quantum Crystal Ariel Haziot,1 Xavier Rojas,1 Andrew D. Fefferman,1 John R crystals may irreversibly deform. This phenomenon is known as plasticity and it is due to the motion and in the zero temperature limit, helium 4 crystals present a giant plasticity that is anisotropic and reversible

  8. A multi-scale analysis of the crystallization of amorphous germanium telluride using ab initio simulations and classical crystallization theory

    E-Print Network [OSTI]

    Anantram, M. P.

    simulations and classical crystallization theory Jie Liu, Xu Xu, Lucien Brush, and M. P. Anantram Citation telluride using ab initio simulations and classical crystallization theory Jie Liu,1 Xu Xu,1 Lucien Brush,2

  9. Crystal structure and interaction dependence of the crystal-melt interfacial free energy

    E-Print Network [OSTI]

    Davidchack, Ruslan L.; Laird, Brian Bostian

    2005-03-01T23:59:59.000Z

    we examine, via molecular simulation, the interfacial free energies for a large number of systems interacting with inverse-power potentials of varying range, crystal orientation, and crystal structure (fcc or bcc). By focusing on a general class... of model interaction potentials 0031-9007= understanding of the dependence of .0013 on is largely empirical. In 1950, Turnbull values of .0013 for a variety of materials, ob- from nucleation rate experiments. ed a strong correlation between the en- per...

  10. Growth and characterization of diammonium copper disulphate hexahydrate single crystal

    SciTech Connect (OSTI)

    Siva Sankari, R. [Department of Physics, Agni College of Technology, Thalambur, Chennai 603103 (India); Perumal, Rajesh Narayana, E-mail: r.shankarisai@gmail.com [Department of Physics, SSN College of Engineering, Kalavakkam, Chennai 603110 (India)

    2014-03-01T23:59:59.000Z

    Graphical abstract: Diammonium copper disulphate hexahydrate (DACS) is one of the most promising inorganic dielectric crystals with exceptional mechanical properties. Good quality crystals of DACS were grown by using solution method in a period of 30 days. The grown crystals were subjected to single crystal X-ray diffraction analysis in order to establish their crystalline nature. Thermo gravimetric, differential thermal analysis, FTIR, and UV–vis–NIR analysis were performed for the crystal. Several solid state physical parameters have been determined for the grown crystals. The dielectric constant and the dielectric loss and AC conductivity of the grown crystal were studied as a function of frequency and temperature has been calculated and plotted. - Highlights: • Diammonium copper disulphate is grown for the first time and CCDC number obtained. • Thermal analysis is done to see the stability range of the crystals. • Band gap and UV cut off wavelength of the crystal are determined to be 2.4 eV and 472.86 nm, respectively. • Dielectric constant, dielectric loss and AC conductivity are plotted as a function of applied field. - Abstract: Diammonium copper disulphate hexahydrate is one of the most promising inorganic crystals with exceptional dielectric properties. A good quality crystal was harvested in a 30-day period using solution growth method. The grown crystal was subjected to various characterization techniques like single crystal X-ray diffraction analysis, thermo gravimetric, differential thermal analysis, FTIR, and UV–vis–NIR analysis. Unit cell dimensions of the grown crystal have been identified from XRD studies. Functional groups of the title compounds have been identified from FTIR studies. Thermal stability of the samples was checked by TG/DTA studies. Band gap of the crystal was calculated. The dielectric constant and dielectric loss were studied as a function of frequency of the applied field. AC conductivity was plotted as a function of temperature.

  11. Kinetics of growth of spinel crystals in a borosilicate glass

    SciTech Connect (OSTI)

    Alton, Jesse; Plaisted, Trevor J.; Hrma, Pavel R.

    2002-07-01T23:59:59.000Z

    Three aspects of the kinetics of spinel crystallization in a high-level waste (HLW) glass were studied: (1) the effect of nucleation agents on the number density (ns) of spinel crystals, (2) crystallization kinetics in a crushed glass, and (3) crystallization kinetics in a glass preheated at T > TL (liquidus temperature). In glass lacking in nucleation agents, ns was a strong function of temperature. In glasses with noble metals (Rh, Ru, Pd, and Pt), ns increased by up to four orders of magnitude and was nearly independent of temperature. The kinetics of spinel crystallization in crushed glass lacking nucleation agents was dominated by surface crystallization and was described by the Kolmogorov-Johnson-Mehl-Avrami (KJMA) equation with the Avrami exponent n {at} 0.5. For application to HLW glass melter processing, it was necessary to preheat glass at T > TL to eliminate the impact of temperature history and surface crystallization on crystal nucleation and growth. In the temperature range of glass processing, crystals descend under gravity when they reach a critical size. Below this critical size, crystallization kinetics is described by the KJMA equation and above the critical size by the Hixson-Crowell equation. At low temperatures, at which glass viscosity is high and diffusion is slow, the KJMA equation represents crystal growth from nucleation to equilibrium. As ns increases, the temperature interval of the transition from the KJMA to Hixson-Crowell regime shifts to a higher temperature.

  12. Kinetics of growth of spinel crystals in a borosilicate glass

    SciTech Connect (OSTI)

    Alton, Jesse; Plaisted, Trevor J.; Hrma, Pavel R.

    2002-08-08T23:59:59.000Z

    Three aspects of the kinetics of spinel crystallization in a high-level waste (HLW) glass were studied: (1) the effect of nucleation agents on the number density (ns) of spinel crystals, (2) crystallization kinetics in a crushed glass, and (3) crystallization kinetics in a glass preheated at T>TL (liquidus temperature). In glass lacking in nucleation agens, ns was a strong function of temperature. In glasses with noble metals (Rh, Ru, Pd, and Pt), ns increased by up to four orders of magnitude and was nearly independent of temperature. The kinetics of spinel crystallization in crushed glass lacking nucleation agents was dominated by surface crystallization and was described by the Kolmogorov-Johnson-Mehl-Avrami (KJMA) equation with the Avrami exponent n~0.5. For application to HLW glass melter processing, it was necessary to preheat glass at T>TL to eliminate the impact of temperature history and surface crystallization on crystal nucleation and growth. In the temperature range of glass processing, crystals descend under gravity when they reach a critical size. Below this critical size, crystallization kinetics is described by the KJMA equation and above the critical size by the Hixson-Crowell equation. At low temperatures, at which glass viscosity is high and diffusion is slow, the KJMA equation represents crystal growth from nucleation to equilibrium. As ns increases, the temperature interval of the transition from the KJMA to Hisxon-Crowell regime shifts to a higher temperature.

  13. High energy resolution, high angular acceptance crystal monochromator

    DOE Patents [OSTI]

    Alp, Ercan E. (Bolingbrook, IL); Mooney, Timothy M. (Westmont, IL); Toellner, Thomas (Green Bay, WI)

    1996-06-04T23:59:59.000Z

    A 4-bounce dispersive crystal monochromator reduces the bandpass of synchrotron radiation to a 10-50 meV range without sacrificing angular acceptance. The monochromator includes the combination of an asymmetrical channel-cut single crystal of lower order reflection and a symmetrical channel-cut single crystal of higher order reflection in a nested geometric configuration. In the disclosed embodiment, a highly asymmetrically cut (.alpha.=20) outer silicon crystal (4 2 2) with low order reflection is combined with a symmetrically cut inner silicon crystal (10 6 4) with high order reflection to condition a hard x-ray component (5-30 keV) of synchrotron radiation down to the .mu.eV-neV level. Each of the crystals is coupled to the combination of a positioning inchworm and angle encoder via a respective rotation stage for accurate relative positioning of the crystals and precise energy tuning of the monochromator.

  14. High energy resolution, high angular acceptance crystal monochromator

    DOE Patents [OSTI]

    Alp, E.E.; Mooney, T.M.; Toellner, T.

    1996-06-04T23:59:59.000Z

    A 4-bounce dispersive crystal monochromator reduces the bandpass of synchrotron radiation to a 10-50 meV range without sacrificing angular acceptance. The monochromator includes the combination of an asymmetrical channel-cut single crystal of lower order reflection and a symmetrical channel-cut single crystal of higher order reflection in a nested geometric configuration. In the disclosed embodiment, a highly asymmetrically cut ({alpha}=20) outer silicon crystal (4 2 2) with low order reflection is combined with a symmetrically cut inner silicon crystal (10 6 4) with high order reflection to condition a hard x-ray component (5--30 keV) of synchrotron radiation down to the {micro}eV-neV level. Each of the crystals is coupled to the combination of a positioning inchworm and angle encoder via a respective rotation stage for accurate relative positioning of the crystals and precise energy tuning of the monochromator. 7 figs.

  15. Low Radioactivity Crystals for Neutrinoless Double Beta Decay Detectors

    SciTech Connect (OSTI)

    Dafinei, Ioan [Sezione INFN di Roma, P-le Aldo Moro 2, Roma I-00185 (Italy)

    2011-04-27T23:59:59.000Z

    The production of crystals needed for rare events physics represent a relatively new, exciting challenge in the field of materials science and engineering. Extremely low concentration of radioactive impurities and very high crystal perfection is required for the crystals to be used in experiments in which the main concerns are the reduction of the background and the use of high sensitivity detectors. A further complication is the fact that for an experiment with a significant discovery potential, relatively large quantities of crystals are needed. The present work makes a review of the general problems related to the production of crystals for rare events physics and gives details related to the production of the TeO{sub 2} crystals needed for the major experiment in this field using bolometric technique, namely the CUORE experiment. The potential use of crystals for future double beta decay experiments is also discussed.

  16. Influence of Substrate on Crystallization in Polythiophene/fullerene Blends

    SciTech Connect (OSTI)

    C He; D Germack; J Kline; D Delongchamp; D Fischer; C Snyder; M Toney; J Kushmerick; L Richter

    2011-12-31T23:59:59.000Z

    The nanoscale morphology of the active layer in organic, bulk heterojunction (BHJ) solar cells is crucial to device performance. Often a combination of casting conditions and post deposition thermal treatment is used to optimize the morphology. In general, the development of microscopic crystals is deleterious, as the exciton diffusion length is {approx}10 nm. We find that the microscopic crystallization behavior in polythiophene/fullerene blends is strongly influenced by the substrate on which the BHJ is cast. With a silicon oxide substrate, the crystal nucleation density is high and significant crystallization occurs at a temperature of 140 C. On more hydrophobic substrates, significantly higher temperatures are required for observable crystallization. This difference is attributed to the interfacial segregation of the PCBM, controlled by the substrate surface energy. The substrate dependence of crystallization has significant implications on the fullerene crystal growth mechanisms and practical implications for device studies.

  17. Partial rotational lattice order–disorder in stefin B crystals

    SciTech Connect (OSTI)

    Renko, Miha [Josef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins, Jamova 39, SI-1000 Ljubljana (Slovenia); Taler-Ver?i?, Ajda [Josef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Miheli?, Marko [Josef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins, Jamova 39, SI-1000 Ljubljana (Slovenia); Žerovnik, Eva [Josef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Turk, Dušan, E-mail: dusan.turk@ijs.si [Josef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins, Jamova 39, SI-1000 Ljubljana (Slovenia)

    2014-04-01T23:59:59.000Z

    Crystal lattice disorders are a phenomenon which may hamper the determination of macromolecular crystal structures. Using the case of the crystal structure of stefin B, identification of rotational order–disorder and structure determination are described. At present, the determination of crystal structures from data that have been acquired from twinned crystals is routine; however, with the increasing number of crystal structures additional crystal lattice disorders are being discovered. Here, a previously undescribed partial rotational order–disorder that has been observed in crystals of stefin B is described. The diffraction images revealed normal diffraction patterns that result from a regular crystal lattice. The data could be processed in space groups I4 and I422, yet one crystal exhibited a notable rejection rate in the higher symmetry space group. An explanation for this behaviour was found once the crystal structures had been solved and refined and the electron-density maps had been inspected. The lattice of stefin B crystals is composed of five tetramer layers: four well ordered layers which are followed by an additional layer of alternatively placed tetramers. The presence of alternative positions was revealed by the inspection of electron-density score maps. The well ordered layers correspond to the crystal symmetry of space group I422. In addition, the positions of the molecules in the additional layer are related by twofold rotational axes which correspond to space group I422; however, these molecules lie on the twofold axis and can only be related in a statistical manner. When the occupancies of alternate positions and overlapping are equal, the crystal lattice indeed fulfills the criteria of space group I422; when these occupancies are not equal, the lattice only fulfills the criteria of space group I4.

  18. Symmetric Satellite Swarms and Choreographic Crystals

    E-Print Network [OSTI]

    Latham Boyle; Jun Yong Khoo; Kendrick Smith

    2014-07-22T23:59:59.000Z

    In this paper, we introduce a natural dynamical analogue of crystalline order, which we call choreographic order. In an ordinary (static) crystal, a high degree of symmetry may be achieved through a careful arrangement of the fundamental repeated elements. In the dynamical analogue, a high degree of symmetry may be achieved by having the fundamental elements perform a carefully choreographed dance. For starters, we show how to construct and classify all symmetric satellite constellations. Then we explain how to generalize these ideas to construct and classify choreographic crystals more broadly. We introduce a quantity, called the "choreography" of a given configuration. We discuss the possibility that some (naturally occurring or artificial) many-body or condensed-matter systems may exhibit choreographic order, and suggest natural experimental signatures that could be used to identify and characterize such systems.

  19. Crystallizing Transmembrane Peptides in Lipidic Mesophases

    SciTech Connect (OSTI)

    Höfer, Nicole; Aragão, David; Caffrey, Martin (Trinity)

    2011-09-28T23:59:59.000Z

    Structure determination of membrane proteins by crystallographic means has been facilitated by crystallization in lipidic mesophases. It has been suggested, however, that this so-called in meso method, as originally implemented, would not apply to small protein targets having {le}4 transmembrane crossings. In our study, the hypothesis that the inherent flexibility of the mesophase would enable crystallogenesis of small proteins was tested using a transmembrane pentadecapeptide, linear gramicidin, which produced structure-grade crystals. This result suggests that the in meso method should be considered as a viable means for high-resolution structure determination of integral membrane peptides, many of which are predicted to be coded for in the human genome.

  20. DHS Internship Summary-Crystal Assembly at Different Length Scales

    SciTech Connect (OSTI)

    Mishchenko, L

    2009-08-06T23:59:59.000Z

    I was part of a project in which in situ atomic force microscopy (AFM) was used to monitor growth and dissolution of atomic and colloidal crystals. At both length scales, the chemical environment of the system greatly altered crystal growth and dissolution. Calcium phosphate was used as a model system for atomic crystals. A dissolution-reprecipitation reaction was observed in this first system, involving the conversion of brushite (DCPD) to octacalcium phosphate (OCP). In the second system, polymeric colloidal crystals were dissolved in an ionic solvent, revealing the underlying structure of the crystal. The dissolved crystal was then regrown through an evaporative step method. Recently, we have also found that colloids can be reversibly deposited in situ onto an ITO (indium tin oxide) substrate via an electrochemistry setup. The overall goal of this project was to develop an understanding of the mechanisms that control crystallization and order, so that these might be controlled during material synthesis. Controlled assembly of materials over a range of length scales from molecules to nanoparticles to colloids is critical for designing new materials. In particular, developing materials for sensor applications with tailorable properties and long range order is important. In this work, we examine two of these length scales: small molecule crystallization of calcium phosphate (whose crystal phases include DCPD, OCP, and HAP) and colloidal crystallization of Poly(methyl methacrylate) beads. Atomic Force Microscopy is ideal for this line of work because it allows for the possibility of observing non-conducting samples in fluid during growth with high resolution ({approx} 10 nm). In fact, during atomic crystal growth one can observe changes in atomic steps, and with colloidal crystals, one can monitor the individual building blocks of the crystal. Colloids and atoms crystallize under the influence of different forces acting at different length scales as seen in Table 1. In particular, molecular crystals, which are typically dominated by ionic and covalent bonding, are an order of magnitude more strongly bonded than colloidal crystals. In molecular crystals, ordering is driven by the interaction potentials between molecules. By contrast, colloidal assembly is a competition between the repulsive electrostatic forces that prevent aggregation in solution (due to surface charge), and short-range van der Waals and entropic forces that leads to ordering. Understanding atomic crystallization is fundamentally important for fabrication of tailorable crystalline materials, for example for biological or chemical sensors. The transformation of brushite to OCP not only serves as a model system for atomic crystal growth (applicable to many other crystal growth processes), but is also important in bone cements. Colloidal crystals have unique optical properties which respond to chemical and mechanical stimuli, making them very important for sensing applications. The mechanism of colloidal crystal assembly is thus fundamentally important. Our in situ dissolution and regrowth experiments are one good method of analyzing how these crystals pack under different conditions and how defect sites are formed and filled. In these experiments, a silica additive was used to strengthen the colloidal crystal during initial assembly (ex situ) and to increase domain size and long range order. Reversible electrodeposition of colloids onto a conductive substrate (ITO in our case) is another system which can further our knowledge of colloidal assembly. This experiment holds promise of allowing in situ observation of colloidal crystal growth and the influence of certain additives on crystal order. The ultimate goal would be to achieve long range order in these crystals by changing the surface charge or the growth environment.

  1. UCN transport simulation in solid deuterium crystals

    E-Print Network [OSTI]

    Yu. N. Pokotilovski

    2012-03-04T23:59:59.000Z

    The extraction efficiency of ultracold neutrons from cryogenic moderators depends critically on the neutron transparency of the moderator material. The Monte Carlo simulation of the probability of the UCN going out from non-ideal (disordered) solid deuterium crystals has been performed. It was based on the use of the correlation function describing the density fluctuations in a disordered material, the latter being inferred from the measured very low neutron energy total cross sections for this material.

  2. Dynamics of Quantum Dot Photonic Crystal Lasers

    E-Print Network [OSTI]

    Bryan Ellis; Ilya Fushman; Dirk Englund; Bingyang Zhang; Yoshihisa Yamamoto; Jelena Vuckovic

    2007-03-07T23:59:59.000Z

    Quantum dot photonic crystal membrane lasers were fabricated and the large signal modulation characteristics were studied. We find that the modulation characteristics of quantum dot lasers can be significantly improved using cavities with large spontaneous emission coupling factor. Our experiments show, and simulations confirm, that the modulation rate is limited by the rate of carrier capture into the dots to around 30GHz in our present system.

  3. Method for fabricating apatite crystals and ceramics

    DOE Patents [OSTI]

    Soules, Thomas F.; Schaffers, Kathleen I.; Tassano, Jr., John B.; Hollingsworth, Joel P.

    2013-09-10T23:59:59.000Z

    The present invention provides a method of crystallizing Yb:C-FAP [Yb.sup.3+:Ca.sub.5(PO.sub.4).sub.3F], by dissolving the Yb:C-FAP in an acidic solution, following by neutralizing the solution. The present invention also provides a method of forming crystalline Yb:C-FAP by dissolving the component ingredients in an acidic solution, followed by forming a supersaturated solution.

  4. Predicting Polymeric Crystal Structures by Evolutionary Algorithms

    E-Print Network [OSTI]

    Qiang Zhu; Vinit Sharma; Artem R Oganov; Rampi Ramprasad

    2014-06-05T23:59:59.000Z

    The recently developed evolutionary algorithm USPEX proved to be a tool that enables accurate and reliable prediction of structures for a given chemical composition. Here we extend this method to predict the crystal structure of polymers by performing constrained evolutionary search, where each monomeric unit is treated as one or several building blocks with fixed connectivity. This greatly reduces the search space and allows the initial structure generation with different sequences and packings using these blocks. The new constrained evolutionary algorithm is successfully tested and validated on a diverse range of experimentally known polymers, namely polyethylene (PE), polyacetylene (PA), poly(glycolic acid) (PGA), poly(vinyl chloride) (PVC), poly(oxymethylene) (POM), poly(phenylene oxide) (PPO), and poly (p-phenylene sulfide) (PPS). By fixing the orientation of polymeric chains, this method can be further extended to predict all polymorphs of poly(vinylidene fluoride) (PVDF), and the complex linear polymer crystals, such as nylon-6 and cellulose. The excellent agreement between predicted crystal structures and experimentally known structures assures a major role of this approach in the efficient design of the future polymeric materials.

  5. New organic crystals for pulse shape discrimination

    SciTech Connect (OSTI)

    Hull, G; Zaitseva, N; Cherepy, N; Newby, J; Stoeffl, W; Payne, S

    2008-07-16T23:59:59.000Z

    Efficient, readily-available, low-cost, high-energy neutron detectors can play a central role in detecting illicit nuclear weapons since neutrons are a strong indication for the presence of fissile material such as Plutonium and Highly-Enriched Uranium. The main challenge in detecting fast neutrons consists in the discrimination of the signal from the gamma radiation background. At present, the only well-investigated organic crystal scintillator for fast neutron detection, in a n/{gamma} mixed field, is stilbene, which while offering good pulse shape discrimination, is not widely used because of its limited availability and high cost. In this work we report the results of our studies made with a number of new organic crystals, which exhibit pulse shape discrimination for detection of fast neutrons. In particular 1,1,4,4-tetraphenyl-1,3-butadiene features a light yield higher than anthracene and a Figure of Merit (FOM) for the pulse shape discrimination better than stilbene. New crystals are good candidates for the low-cost solution growth method, thus representing promising organic scintillators for widespread deployment for high-energy neutron detection.

  6. Ytterbium-doped borate fluoride laser crystals and lasers

    DOE Patents [OSTI]

    Schaffers, Kathleen I. (Pleasanton, CA); DeLoach, Laura D. (Manteca, CA); Payne, Stephen A. (Castro Valley, CA); Keszler, Douglas A. (Corvallis, OK)

    1997-01-01T23:59:59.000Z

    A new class of solid state laser crystals and lasers are formed from Yb-doped borate fluoride host crystals. The general formula for the host crystals is MM'(BO.sub.3)F, where M, M' are monovalent, divalent aria trivalent metal cations. A particular embodiment of the invention is Yb-doped BaCaBO.sub.3 F (Yb:BCBF). BCBF and some of the related derivative crystals are capable of nonlinear frequency conversion, whereby the fundamental of the laser is converted to a longer or shorter wavelength. In this way, these new crystals can simultaneously serve as self-frequency doubling crystals and laser materials within the laser resonator.

  7. Ytterbium-doped borate fluoride laser crystals and lasers

    DOE Patents [OSTI]

    Schaffers, K.I.; DeLoach, L.D.; Payne, S.A.; Keszler, D.A.

    1997-10-14T23:59:59.000Z

    A new class of solid state laser crystals and lasers are formed from Yb-doped borate fluoride host crystals. The general formula for the host crystals is MM{prime}(BO{sub 3})F, where M, M{prime} are monovalent, divalent aria trivalent metal cations. A particular embodiment of the invention is Yb-doped BaCaBO{sub 3}F (Yb:BCBF). BCBF and some of the related derivative crystals are capable of nonlinear frequency conversion, whereby the fundamental of the laser is converted to a longer or shorter wavelength. In this way, these new crystals can simultaneously serve as self-frequency doubling crystals and laser materials within the laser resonator. 6 figs.

  8. Non-linear optical crystal vibration sensing device

    DOE Patents [OSTI]

    Kalibjian, R.

    1994-08-09T23:59:59.000Z

    A non-linear optical crystal vibration sensing device including a photorefractive crystal and a laser is disclosed. The laser produces a coherent light beam which is split by a beam splitter into a first laser beam and a second laser beam. After passing through the crystal the first laser beam is counter-propagated back upon itself by a retro-mirror, creating a third laser beam. The laser beams are modulated, due to the mixing effect within the crystal by vibration of the crystal. In the third laser beam, modulation is stable and such modulation is converted by a photodetector into a usable electrical output, intensity modulated in accordance with vibration applied to the crystal. 3 figs.

  9. Method for surface treatment of a cadmium zinc telluride crystal

    DOE Patents [OSTI]

    James, Ralph (5420 Lenore Ave., Livermore, CA 94550); Burger, Arnold (753 Adkisson La., Nashville, TN 37205); Chen, Kuo-Tong (7800 River Fork Dr., Nashville, TN 37221); Chang, Henry (6535 Premier Dr., Apt. A7, Nashville, TN 37209)

    1999-01-01T23:59:59.000Z

    A method for treatment of the surface of a CdZnTe (CZT) crystal that reduces surface roughness (increases surface planarity) and provides an oxide coating to reduce surface leakage currents and thereby, improve resolution. A two step process is disclosed, etching the surface of a CZT crystal with a solution of lactic acid and bromine in ethylene glycol, following the conventional bromine/methanol etch treatment, and after attachment of electrical contacts, oxidizing the CZT crystal surface.

  10. Solution-grown crystals for neutron radiation detectors, and methods of solution growth

    DOE Patents [OSTI]

    Zaitseva, Natalia; Carman, M Leslie; Payne, Steve

    2014-10-28T23:59:59.000Z

    An organic crystal according to one embodiment includes an organic crystal comprising diphenylacetylene and stilbene or a stilbene derivative, the crystal having physical characteristics of formation from solution, the organic crystal exhibiting a signal response signature for neutrons from a radioactive source. A system according to one embodiment includes an organic crystal comprising diphenylacetylene and stilbene or a stilbene derivative, the crystal having physical characteristics of formation from solution, the organic crystal exhibiting a signal response signature for neutrons from a radioactive source; and a photodetector for detecting the signal response of the organic crystal. Methods of making such crystals are also provided.

  11. A Submarine Welded Ignimbrite-Crystal-Rich Sandstone Facies Associatio...

    Open Energy Info (EERE)

    Ignimbrite-Crystal-Rich Sandstone Facies Association In The Cambrian Tyndall Group, Western Tasmania, Australia Jump to: navigation, search OpenEI Reference LibraryAdd to...

  12. HYDROGEN CHEMISORPTION ON Pt SINGLE CRYSTAL SURFACES IN ACIDIC SOLUTIONS

    E-Print Network [OSTI]

    Ross, Jr., Philip N.

    2012-01-01T23:59:59.000Z

    t for the Adsorption of Hydrogen on Pt Single CrystalSubmitted to Surface Science HYDROGEN CHEMISORPTION ON Ptheats of adsorption of hydrogen on (111) and (100) sur-

  13. Supercontinuum generation in photonic crystal fibres: Modelling and dispersion engineering

    E-Print Network [OSTI]

    Supercontinuum generation in photonic crystal fibres: Modelling and dispersion engineering . . . . . . . . . . . . . . . . . 22 2.4 The split-step Fourier method . . . . . . . . . . . . . . . . . . 25 #12;iv CONTENTS 2

  14. Surface treatment and protection method for cadmium zinc telluride crystals

    DOE Patents [OSTI]

    Wright, Gomez W. (Nashville, TN); James, Ralph B. (Livermore, CA); Burger, Arnold (Nashville, TN); Chinn, Douglas A. (Livermore, CA)

    2003-01-01T23:59:59.000Z

    A method for treatment of the surface of a CdZnTe (CZT) crystal that provides a native dielectric coating to reduce surface leakage currents and thereby, improve the resolution of instruments incorporating detectors using CZT crystals. A two step process is disclosed, etching the surface of a CZT crystal with a solution of the conventional bromine/methanol etch treatment, and after attachment of electrical contacts, passivating the CZT crystal surface with a solution of 10 w/o NH.sub.4 F and 10 w/o H.sub.2 O.sub.2 in water.

  15. Surface Treatment And Protection Method For Cadium Zinc Telluride Crystals

    DOE Patents [OSTI]

    Wright, Gomez W. (Nashville, TN); James, Ralph B. (Livermore, CA); Burger, Arnold (Nashville, TN); Chinn, Douglas A. (Livermore, CA)

    2006-02-21T23:59:59.000Z

    A method for treatment of the surface of a CdZnTe (CZT) crystal that provides a native dielectric coating to reduce surface leakage currents and thereby, improve the resolution of instruments incorporating detectors using CZT crystals. A two step process is disclosed, etching the surface of a CZT crystal with a solution of the conventional bromine/methanol etch treatment, and after attachment of electrical contacts, passivating the CZT crystal surface with a solution of 10 w/o NH4F and 10 w/o H2O2 in water.

  16. Spectroscopic, thermal and structural studies on manganous malate crystals

    SciTech Connect (OSTI)

    Thomas, J., E-mail: smartlabindia@gmail.com; Lincy, A., E-mail: lincymaria@gmail.com; Mahalakshmi, V.; Saban, K. V. [Smart Materials Analytic Research and Technology (SMART), Department of Physics, St. Berchmans College (India)] [Smart Materials Analytic Research and Technology (SMART), Department of Physics, St. Berchmans College (India)

    2013-01-15T23:59:59.000Z

    Prismatic crystals of manganous malate have been prepared by controlled ionic diffusion in hydrosilica gel. The structure was elucidated using single crystal X-ray diffraction. The crystals are orthorhombic with space group Pbca. Vibrations of the functional groups were identified by the FTIR spectrum. Thermogravimetric and differential thermal analyses (TG-DTA) were carried out to explore the thermal decomposition pattern of the material. Structural information derived from FTIR and TG-DTA studies is in conformity with the single crystal XRD data.

  17. Observation of scattering and absorption centers in lead fluoride crystals

    E-Print Network [OSTI]

    Patrick Achenbach

    2006-06-22T23:59:59.000Z

    For the first time, lead fluoride is used as a fast and compact material in electromagnetic calorimetry. Excellent optical and mechanical properties of the pure Cherenkov crystals are necessary for the A4 collaboration to perform a measurement of the nucleon's strange form factors. Visible scattering and absorption centers as well as surface damages have been investigated to characterize the quality of more than one thousand crystals. Besides, transmittance measurements have been performed on all crystals to reveal absorption bands produced by intrinsic or impurity related point-structure defects. As a consequence, 89 crystals had to be replaced by the Chinese manufacturer SICCAS.

  18. LOW-TEMPERATURE CRYSTALLIZATION OF AMORPHOUS SILICATE IN ASTROPHYSICAL ENVIRONMENTS

    SciTech Connect (OSTI)

    Tanaka, Kyoko K.; Yamamoto, Tetsuo [Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 (Japan); Kimura, Hiroshi [Center for Planetary Science, Kobe 657-8501 (Japan)

    2010-07-01T23:59:59.000Z

    We construct a theoretical model for low-temperature crystallization of amorphous silicate grains induced by exothermic chemical reactions. As a first step, the model is applied to the annealing experiments, in which the samples are (1) amorphous silicate grains and (2) amorphous silicate grains covered with an amorphous carbon layer. We derive the activation energies of crystallization for amorphous silicate and amorphous carbon from the analysis of the experiments. Furthermore, we apply the model to the experiment of low-temperature crystallization of an amorphous silicate core covered with an amorphous carbon layer containing reactive molecules. We clarify the conditions of low-temperature crystallization due to exothermic chemical reactions. Next, we formulate the crystallization conditions so as to be applicable to astrophysical environments. We show that the present crystallization mechanism is characterized by two quantities: the stored energy density Q in a grain and the duration of the chemical reactions {tau}. The crystallization conditions are given by Q>Q{sub min} and {tau} < {tau}{sub cool} regardless of details of the reactions and grain structure, where {tau}{sub cool} is the cooling timescale of the grains heated by exothermic reactions, and Q{sub min} is minimum stored energy density determined by the activation energy of crystallization. Our results suggest that silicate crystallization occurs in wider astrophysical conditions than hitherto considered.

  19. Insights into the crystal chemistry of Earth materials rendered...

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

    density between bonded pairs of atoms for a relatively large number of oxide and silicate crystals and siloxane molecules. The distribution of the electron density shows that...

  20. Damage due to salt crystallization in porous media

    E-Print Network [OSTI]

    Noushine Shahidzadeh Bonn; Francois Bertrand; Daniel Bonn

    2009-06-13T23:59:59.000Z

    We investigate salt crystallization in porous media that can lead to their disintegration. For sodium sulfate we show for the first time experimentally that when anhydrous crystals are wetted with water, there is very rapid growth of the hydrated form of sulfate in clusters that nucleate on anhydrous salt micro crystals. The molar volume of the hydrated crystals being four times bigger, the growth of these clusters can generate stresses in excess of the tensile strength of the stone and lead therefore to damage.

  1. Solar cell structure incorporating a novel single crystal silicon material

    DOE Patents [OSTI]

    Pankove, Jacques I. (Princeton, NJ); Wu, Chung P. (Trenton, NJ)

    1983-01-01T23:59:59.000Z

    A novel hydrogen rich single crystal silicon material having a band gap energy greater than 1.1 eV can be fabricated by forming an amorphous region of graded crystallinity in a body of single crystalline silicon and thereafter contacting the region with atomic hydrogen followed by pulsed laser annealing at a sufficient power and for a sufficient duration to recrystallize the region into single crystal silicon without out-gassing the hydrogen. The new material can be used to fabricate semiconductor devices such as single crystal silicon solar cells with surface window regions having a greater band gap energy than that of single crystal silicon without hydrogen.

  2. Crystal_Reporting_9_1 LSUNO_LSUSH

    E-Print Network [OSTI]

    , products and services. Oracle Corporation and its affiliates will not be responsible for any loss, costs........................................................................................3 Running Crystal Reports......................................................................................................13 Run a Single Report for Multiple Departments

  3. Diffraction crystals for sagittally focusing x-rays

    DOE Patents [OSTI]

    Ice, G.E.; Sparks, C.J. Jr.

    1982-06-07T23:59:59.000Z

    The invention is a new type of diffraction crystal designed for sagittally focusing photons of various energies. The invention is based on the discovery that such focusing is not obtainable with conventional crystals because of distortion resulting from anticlastic curvature. The new crystal comprises a monocrystalline base having a front face contoured for sagittally focusing photons and a back face provided with rigid, upstanding, stiffening ribs restricting anticlastic curvature. When mounted in a suitable bending device, the reflecting face of the crystal can be adjusted to focus photons having any one of a range of energies.

  4. Diffraction crystal for sagittally focusing x-rays

    DOE Patents [OSTI]

    Ice, Gene E. (Oak Ridge, TN); Sparks, Jr., Cullie J. (Oak Ridge, TN)

    1984-01-01T23:59:59.000Z

    The invention is a new type of diffraction crystal designed for sagittally focusing photons of various energies. The invention is based on the discovery that such focusing is not obtainable with conventional crystals because of distortion resulting from anticlastic curvature. The new crystal comprises a monocrystalline base having a front face contoured for sagittally focusing photons and a back face provided with rigid, upstanding, stiffening ribs restricting anticlastic curvature. When mounted in a suitable bending device, the reflecting face of the crystal can be adjusted to focus photons having any one of a range of energies.

  5. New Crystal Structures Lift Fog around Protein Folding

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

    New Crystal Structures Lift Fog around Protein Folding Print Nature's proteins set a high bar for nanotechnology. Macromolecules forged from peptide chains of amino acids, these...

  6. Variation in Machinability of Single Crystal Materials in Micromachining

    E-Print Network [OSTI]

    2006-01-01T23:59:59.000Z

    impact on the critical DOC at which such materials can becritical depth of cut and crystallographic orientation was found on single crystal materials (

  7. Electric field effects in liquid crystals with dielectric dispersion

    SciTech Connect (OSTI)

    Lavrentovich, Oleg D. [Kent State University

    2014-11-29T23:59:59.000Z

    The project is focused on the experimental and theoretical exploration of the coupling of an externally applied electric field and a nematic liquid crystal.

  8. Temperature-insensitive phase-matched optical harmonic conversion crystal

    DOE Patents [OSTI]

    Barker, C.E.; Eimerl, D.; Velsko, S.P.; Roberts, D.

    1993-11-23T23:59:59.000Z

    Temperature-insensitive, phase-matched harmonic frequency conversion of laser light at a preferred wavelength of 1.064 microns can be achieved by use of a crystal of deuterated l-arginine phosphate. The crystal is cut and oriented so that the laser light propagates inside the crystal along one of several required directions, which correspond to a temperature-insensitive, phase-matching locus. The method of measuring and calculating the temperature-insensitive, phase-matching angles can be extended to other fundamental wavelengths and other crystal compositions. 12 figures.

  9. Temperature-insensitive phase-matched optical harmonic conversion crystal

    DOE Patents [OSTI]

    Barker, Charles E. (Sunnyvale, CA); Eimerl, David (Livermore, CA); Velsko, Stephan P. (Livermore, CA); Roberts, David (Sagamore Hills, OH)

    1993-01-01T23:59:59.000Z

    Temperature-insensitive, phase-matched harmomic frequency conversion of laser light at a preferred wavelength of 1.064 microns can be achieved by use of a crystal of deuterated l-arginine phosphate. The crystal is cut and oriented so that the laser light propagates inside the crystal along one of several required directions, which correspond to a temperature-insensitive, phase-matching locus. The method of measuring and calculating the temperature-insensitive, phase-matching angles can be extended to other fundamental wavelengths and other crystal compositions.

  10. A computational investigation of nucleation processes in organic crystals

    E-Print Network [OSTI]

    Beckham, Gregg Tyler

    2008-01-01T23:59:59.000Z

    Nucleation processes are ubiquitous in nature and technology. For instance, cloud formation in the atmosphere, the casting of metals, protein crystallization, biomineralization, the production of porous materials, and ...

  11. Method for the preparation of photochromic insulating crystals

    DOE Patents [OSTI]

    Abraham, Marvin M. (Oak Ridge, TN); Boldu, Jose L. (Mexico City, MX); Chen, Yok (Oak Ridge, TN); Orera, Victor M. (Zaragosa, ES)

    1986-01-01T23:59:59.000Z

    A method for preparing reversible-photochromic magnesium oxide (MgO) crystals. Single crystals of MgO doped with both lithium (Li) and nickel (Ni) are grown by a conventional arc fusion method. The as-grown crystals are characterized by an amber coloration. The crystals lose the amber coloration and become photochromic when they are thermochemically reduced by heating at temperatures greater than 1000.degree. K. in a hydrogen atmosphere. Alternate irradiation with UV and visible light result in rejuvenation and bleaching of the amber coloration, respectively.

  12. Orientationally Glassy Crystals of Janus Spheres

    E-Print Network [OSTI]

    Shan Jiang; Jing Yan; Jonathan K. Whitmer; Stephen M. Anthony; Erik Luijten; Steve Granick

    2014-06-10T23:59:59.000Z

    Colloidal Janus spheres in water (one hemisphere attractive and the other repulsive) assemble into two-dimensional hexagonal crystals with orientational order controlled by anisotropic interactions. We exploit the decoupled translational and rotational order to quantify the orientational dynamics. Via imaging experiments and Monte Carlo simulations we demonstrate that the correlations in the orientation of individual Janus spheres exhibit glasslike dynamics that can be controlled via the ionic strength. Thus, these colloidal building blocks provide a particularly suitable model glass system for elucidating nontrivial dynamics arising from directional interactions, not captured by the consideration of just translational order.

  13. Crystallization of M-CSF.alpha.

    DOE Patents [OSTI]

    Pandit, Jayvardhan (Mystic, CT); Jancarik, Jarmila (Walnut Creek, CA); Kim, Sung-Hou (Moraga, CA); Koths, Kirston (El Cerrito, CA); Halenbeck, Robert (San Rafael, CA); Fear, Anna Lisa (Oakland, CA); Taylor, Eric (Oakland, CA); Yamamoto, Ralph (Martinez, CA); Bohm, Andrew (Berkeley, CA)

    1999-01-01T23:59:59.000Z

    The present invention is directed to methods for crystallizing macrophage colony stimulating factor (M-CSF) and to a crystalline M-CSF produced thereby. The present invention is also directed to methods for designing and producing M-CSF agonists and antagonists using information derived from the crystallographic structure of M-CSF. The invention is also directed to methods for screening M-CSF agonists and antagonists. In addition, the present invention is directed to an isolated, purified, soluble and functional M-CSF receptor.

  14. Plasmonic crystal enhanced refractive index sensing

    SciTech Connect (OSTI)

    Stein, Benedikt; Devaux, Eloïse; Genet, Cyriaque, E-mail: genet@unistra.fr; Ebbesen, Thomas W. [ISIS and icRFC, University of Strasbourg and CNRS, 8 allée Gaspard Monge, 67000 Strasbourg (France)

    2014-06-23T23:59:59.000Z

    We demonstrate experimentally how the local anisotropy of the dispersion relation of surface plasmon modes propagating over periodic metal gratings can lead to an enhancement of the figure of merit of refractive index sensors. Exploiting the possibility to acquire defocused images of the Fourier space of a highly stable leakage radiation microscope, we report a twofold increase in sensing sensitivity close to the band gap of a one-dimensional plasmonic crystal where the anisotropy of the band structure is the most important. A practical sensing resolution of O(10{sup ?6}) refractive index units is demonstrated.

  15. Super-collimation by axisymmetric photonic crystals

    SciTech Connect (OSTI)

    Purlys, V.; Gailevi?ius, D.; Peckus, M.; Gadonas, R. [Laser Research Center, Department of Quantum Electronics, Vilnius University, Saul?tekio Ave. 10, LT-10222 Vilnius (Lithuania); Maigyte, L. [Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Colom 11, 08222 Terrassa (Spain); Staliunas, K. [Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Colom 11, 08222 Terrassa (Spain); Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys, 23, 08010 Barcelona (Spain)

    2014-06-02T23:59:59.000Z

    We propose and experimentally show the mechanism of beam super-collimation by axisymmetric photonic crystals, specifically by periodic (in propagation direction) structure of layers of concentric rings. The physical mechanism behind the effect is an inverse scattering cascade of diffracted wave components back into on- and near-axis angular field components, resulting in substantial enhancement of intensity of these components. We explore the super-collimation by numerical calculations and prove it experimentally. We demonstrate experimentally the axial field enhancement up to 7 times in terms of field intensity.

  16. Surface Vibrations in a Model Hcp Crystal

    E-Print Network [OSTI]

    Allen, Roland E.; Alldredg, GP; DEWITTE, FW.

    1972-01-01T23:59:59.000Z

    , and F. W. de Wette, Phys. Rev. B4, 1661 (1971). PHYSICA L RE VIE W 8 VOLUME 6, NUMBE R 2 15 JULY 1972 Surface Vibrations in a Model hcp Crystal R. E. Allen Department of Physics, Texas A @ M University, College Station, Texas 77843 and G. P.... Alldredge and F. %. de bette Department of Physics, University of Texas, Austin, Texas 78712 (Received 16 February 1972) The surface relaxation, vibrational modes, mean-square amplitudes of vibration, etc. , have been calculated for the (0001) surface...

  17. Crystal McDonald | Department of Energy

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 1112011AT&T, Inc.'sEnergyTexas1.SpaceFluorControlsEnergyRev. 1)Crystal McDonald About

  18. Silicon Crystals Inc | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand Jump to:Ezfeedflag JumpID-f < RAPID‎ |Rippey JumpAirPowerSilcio SA Jump to: navigation,Crystals

  19. Crystal, Minnesota: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand JumpConceptual Model, clickInformationNew|CoreCpWing County, Minnesota:Crystal, Minnesota: Energy

  20. Toward photonic-crystal metamaterials: Creating magnetic emitters in photonic crystals

    E-Print Network [OSTI]

    explore the possibility of designing photonic crystals to act as magnetic metamaterials: structures the constituents of natural para- and ferromagnetic materials, these synthetic magnetic emitters can be designed, quantitatively demonstrating that point-defect modes can be designed to have a magnetic character. We choose

  1. Levitated crystals and quasicrystals of metamaterials

    SciTech Connect (OSTI)

    Wang, Zhehui [Los Alamos National Laboratory; Morris, Christopher [Los Alamos National Laboratory; Goree, John A [Dept Phys and Astron., University of Iowa

    2012-07-25T23:59:59.000Z

    New scientific and technological opportunities exist by marrying dusty plasma research with metamaterials. Specifically, by balancing control and self-assembly, certain laboratory plasmas can become a generic levitation platform for novel structure formation and nanomaterial synthesis. We propose to experimentally investigate two dimensional (2D) and three dimensional (3D) levitated structures of metamaterials and their properties. Such structures can self assemble in laboratory plasmas, similar to levitated dust crystals which were discovered in the mid 1990's. Laboratory plasma platform for metamaterial formation eliminates substrates upon which most metamaterials have to be supported. Three types of experiments, with similar setups, are discussed here. Levitated crystal structures of metamaterials using anisotropic microparticles are the most basic of the three. The second experiment examines whether quasicrystals of metamaterials are possible. Quasicrystals, discovered in the 1980's, possess so-called forbidden symmetries according to the conventional crystallography. The proposed experiment could answer many fundamental questions about structural, thermal and dynamical properties of quasicrystals. And finally, how to use nanoparticle coated microparticles to synthesize very long carbon nanotubes is also described. All of the experiments can fit inside a standard International Space Station locker with dimensions of 8-inch x 17-inch X 18-inch. Microgravity environment is deemed essential in particular for large 3D structures and very long carbon nanotube synthesis.

  2. Photonic Crystal Laser-Driven Accelerator Structures

    SciTech Connect (OSTI)

    Cowan, Benjamin M.

    2007-08-22T23:59:59.000Z

    Laser-driven acceleration holds great promise for significantly improving accelerating gradient. However, scaling the conventional process of structure-based acceleration in vacuum down to optical wavelengths requires a substantially different kind of structure. We require an optical waveguide that (1) is constructed out of dielectric materials, (2) has transverse size on the order of a wavelength, and (3) supports a mode with speed-of-light phase velocity in vacuum. Photonic crystals---structures whose electromagnetic properties are spatially periodic---can meet these requirements. We discuss simulated photonic crystal accelerator structures and describe their properties. We begin with a class of two-dimensional structures which serves to illustrate the design considerations and trade-offs involved. We then present a three-dimensional structure, and describe its performance in terms of accelerating gradient and efficiency. We discuss particle beam dynamics in this structure, demonstrating a method for keeping a beam confined to the waveguide. We also discuss material and fabrication considerations. Since accelerating gradient is limited by optical damage to the structure, the damage threshold of the dielectric is a critical parameter. We experimentally measure the damage threshold of silicon for picosecond pulses in the infrared, and determine that our structure is capable of sustaining an accelerating gradient of 300 MV/m at 1550 nm. Finally, we discuss possibilities for manufacturing these structures using common microfabrication techniques.

  3. Stretchable liquid crystal blue phase gels

    E-Print Network [OSTI]

    F. Castles; S. M. Morris; J. M. C. Hung; M. M. Qasim; A. D. Wright; S. Nosheen; S. S. Choi; B. I. Outram; S. J. Elston; C. Burgess; L. Hill; T. D. Wilkinson; H. J. Coles

    2014-01-26T23:59:59.000Z

    Liquid crystalline polymers are materials of considerable scientific interest and technological value to society [1-3]. An important subset of such materials exhibit rubber-like elasticity; these can combine the remarkable optical properties of liquid crystals with the favourable mechanical properties of rubber and, further, exhibit behaviour not seen in either type of material independently [2]. Many of their properties depend crucially on the particular mesophase employed. Stretchable liquid crystalline polymers have previously been demonstrated in the nematic, chiral nematic, and smectic mesophases [2,4]. Here were report the fabrication of a stretchable gel of blue phase I, which forms a self-assembled, three-dimensional photonic crystal that may have its optical properties manipulated by an applied strain and, further, remains electro-optically switchable under a moderate applied voltage. We find that, unlike its undistorted counterpart, a mechanically deformed blue phase exhibits a Pockels electro-optic effect, which sets out new theoretical challenges and new possibilities for low-voltage electro-optic devices.

  4. On the Design of Crystallization-Based Separation Processes: Review and Extension

    E-Print Network [OSTI]

    Grossmann, Ignacio E.

    flow sheets for separations based on fractional crystallization. A series of rules are derived that may Keywords: fractional crystallization, process design, process synthesis Introduction Crystallization. In spite of the popularity of this operation, exceeded in scope only by distillation processes

  5. Polymer-stabilized blue phase liquid crystals: a tutorial [Invited

    E-Print Network [OSTI]

    Wu, Shin-Tson

    Polymer-stabilized blue phase liquid crystals: a tutorial [Invited] Jin Yan and Shin-Tson Wu@mail.ucf.edu Abstract: Blue phase liquid crystals exhibit several attractive features, such as self-assembled three, and submillisecond response time. This tutorial gives step-by-step introduction on basic blue- phase materials

  6. Electromagnetic space-time crystals. II. Fractal computational approach

    E-Print Network [OSTI]

    G. N. Borzdov

    2014-10-20T23:59:59.000Z

    A fractal approach to numerical analysis of electromagnetic space-time crystals, created by three standing plane harmonic waves with mutually orthogonal phase planes and the same frequency, is presented. Finite models of electromagnetic crystals are introduced, which make possible to obtain various approximate solutions of the Dirac equation. A criterion for evaluating accuracy of these approximate solutions is suggested.

  7. Hydrogen plasma enhanced crystallization of hydrogenated amorphous silicon films

    E-Print Network [OSTI]

    Hydrogen plasma enhanced crystallization of hydrogenated amorphous silicon films K. Pangal,a) J. C August 1998; accepted for publication 21 October 1998 We report that a room temperature hydrogen plasma thermal crystallization of amorphous silicon time by a factor of five. Exposure to hydrogen plasma reduces

  8. InfoCrystal: A visual tool for information retrieval

    E-Print Network [OSTI]

    Spoerri, Anselm

    of interest. The InfoCrystal allows users to specify Boolean as well as vector-space queries graphically continuous, multi-variate fields that vary over space and time. Hence, the transformation problem the InfoCrystalTM, that can be used as a visualiza- tion tool as well as a visual query language to help

  9. Simultaneous SHG of orthogonally polarized fundamentals in single QPM crystals

    E-Print Network [OSTI]

    -order parametric nonlinear processes in a single lithium niobate crystal is being undertaken using a new technique cascading interactions can be realized. The use of the higher QPM orders (3rd, 5th or7th) for the type-0, as the respective nonlinear coefficients are dzzz ~27 pm/V and dyyz ~ 4.7 pm/V in lithium niobate crystals. Possible

  10. Crystal engineering of zeolites with graphene Paul Gebhardt,a

    E-Print Network [OSTI]

    Elliott, James

    - dimensional materials to engineer functional inorganic crystals. Introduction The morphology of zeolite that affect crystal synthesis.9­11 Zeolites are microporous materials widely used in industrial catalytic uncover a simple new method for controlling the synthesis of zeolitic materials and, through

  11. Photonic Crystal Slot Waveguide Spectrometer for Detection of Methane

    E-Print Network [OSTI]

    Texas at Austin, University of

    Photonic Crystal Slot Waveguide Spectrometer for Detection of Methane 1 Funded by Environmental. of Electrical and Computer Engineering, University of Texas, Austin #12;Motivation No other chip based optical Similar to: Doping of Semiconductor 3 #12;4 Photonic Crystal Bio-Chemical Sensors Loncar et al, Appl. Phys

  12. Light trapping in photonic crystals Ken Xingze Wang,ab

    E-Print Network [OSTI]

    Cui, Yi

    Light trapping in photonic crystals Ken Xingze Wang,ab Zongfu Yu,bc Victor Liu,bd Aaswath Raman,b Yi Cuief and Shanhui Fan*b We consider light trapping in photonic crystals in the weak material-integrated absorption enhancement by light trapping is proportional to the photonic density of states. The tight bound

  13. Switchable Fresnel lens using polymer-stabilized liquid crystals

    E-Print Network [OSTI]

    Wu, Shin-Tson

    Switchable Fresnel lens using polymer-stabilized liquid crystals Yun-Hsing Fan, Hongwen Ren@mail.ucf.edu http:/lcd.creol.ucf.edu Abstract: A switchable Fresnel zone plate lens is demonstrated using a polymer controllable liquid crystal Fresnel lens," Proc. SPIE 1168, 352-357 (1989). 2. J. S. Patel and K. Rastani

  14. Reflection of focused beams from opal photonic crystals

    E-Print Network [OSTI]

    Jonsson, Fredrik

    . Chutinan, "Full Three-Dimensional Photonic Bandgap Crystals at Near-Infrared Wavelengths," Science 289, 604Reflection of focused beams from opal photonic crystals Karri Varis, Marco Mattila Optoelectronics 10-14, D-55099 Mainz, Germany Abstract: We present a robust method for computing the reflection

  15. Ultraviolet laser beam monitor using radiation responsive crystals

    DOE Patents [OSTI]

    McCann, Michael P. (Oliver Springs, TN); Chen, Chung H. (Knoxville, TN)

    1988-01-01T23:59:59.000Z

    An apparatus and method for monitoring an ultraviolet laser beam includes disposing in the path of an ultraviolet laser beam a substantially transparent crystal that will produce a color pattern in response to ultraviolet radiation. The crystal is exposed to the ultraviolet laser beam and a color pattern is produced within the crystal corresponding to the laser beam intensity distribution therein. The crystal is then exposed to visible light, and the color pattern is observed by means of the visible light to determine the characteristics of the laser beam that passed through crystal. In this manner, a perpendicular cross sectional intensity profile and a longitudinal intensity profile of the ultraviolet laser beam may be determined. The observation of the color pattern may be made with forward or back scattered light and may be made with the naked eye or with optical systems such as microscopes and television cameras.

  16. Studying the magnetic properties of CoSi single crystals

    SciTech Connect (OSTI)

    Narozhnyi, V. N., E-mail: narozhnyivn@gmail.com; Krasnorussky, V. N. [Russian Academy of Sciences, Vereshchagin Institute for High Pressure Physics (Russian Federation)

    2013-05-15T23:59:59.000Z

    The magnetic properties of CoSi single crystals have been measured in a range of temperatures T = 5.5-450 K and magnetic field strengths H {<=} 11 kOe. A comparison of the results for crystals grown in various laboratories allowed the temperature dependence of magnetic susceptibility {chi}(T) = M(T)/H to be determined for a hypothetical 'ideal' (free of magnetic impurities and defects) CoSi crystal. The susceptibility of this ideal crystal in the entire temperature range exhibits a diamagnetic character. The {chi}(T) value significantly increases in absolute value with decreasing temperature and exhibits saturation at the lowest temperatures studied. For real CoSi crystals of four types, paramagnetic contributions to the susceptibility have been evaluated and nonlinear (with respect to the field) contributions to the magnetization have been separated and taken into account in the calculations of {chi}(T).

  17. Shallow melt apparatus for semicontinuous czochralski crystal growth

    DOE Patents [OSTI]

    Wang, Tihu; Ciszek, Theodore F.

    2006-01-10T23:59:59.000Z

    In a single crystal pulling apparatus for providing a Czochralski crystal growth process, the improvement of a shallow melt In a single crystal pulling apparatus for providing a Czochralski crystal growth process, the improvement of a shallow melt crucible (20) to eliminate the necessity supplying a large quantity of feed stock materials that had to be preloaded in a deep crucible to grow a large ingot, comprising a gas tight container a crucible with a deepened periphery (25) to prevent snapping of a shallow melt and reduce turbulent melt convection; source supply means for adding source material to the semiconductor melt; a double barrier (23) to minimize heat transfer between the deepened periphery (25) and the shallow melt in the growth compartment; offset holes (24) in the double barrier (23) to increase melt travel length between the deepened periphery (25) and the shallow growth compartment; and the interface heater/heat sink (22) to control the interface shape and crystal growth rate.

  18. Growing intermetallic single crystals using in situ decanting

    SciTech Connect (OSTI)

    Petrovic, Cedomir; Canfield, Paul; Mellen, Jonathan

    2012-05-16T23:59:59.000Z

    High temperature metallic solution growth is one of the most successful and versatile methods for single crystal growth, and is particularly suited for exploratory synthesis. The method commonly utilizes a centrifuge at room temperature and is very successful for the synthesis of single crystal phases that can be decanted from the liquid below the melting point of the silica ampoule. In this paper, we demonstrate the extension of this method that enables single crystal growth and flux decanting inside the furnace at temperatures above 1200°C. This not only extends the number of available metallic solvents that can be used in exploratory crystal growth but also can be particularly well suited for crystals that have a rather narrow exposed solidification surface in the equilibrium alloy phase diagram.

  19. CrystalPlan: an Experiment Planning Tool for Crystallography

    SciTech Connect (OSTI)

    Zikovsky, Janik L [ORNL; Peterson, Peter F [ORNL; Wang, Xiaoping [ORNL; Frost, Matthew J [ORNL; Hoffmann, Christina [ORNL

    2011-01-01T23:59:59.000Z

    Beam time at large user program based x-ray and neutron scattering facilities is in high demand and always at a premium. CrystalPlan, a highly efficient experiment planning software has been developed to maximize the use of available beamtime per sample per experiment. This program can calculate and optimize the data coverage of a crystal in reciprocal space in a single-crystal diffraction time-of- flight experiment. CrystalPlan can help a user build an experiment plan that will acquire the most data possible, with sufficient coverage but limited redundancy, therefore increasing scientific productivity. A user friendly GUI including a 3D viewer, an automated coverage optimizer, and an option to reorient the crystal for the measurement of selected hkls on specific detector positions are among its useful features. A sample use case of the program with the TOPAZ beamline at SNS will be presented.

  20. EMPIRICAL MODEL FOR FORMULATION OF CRYSTAL-TOLERANT HLW GLASSES

    SciTech Connect (OSTI)

    KRUGER AA; MATYAS J; HUCKLEBERRY AR; VIENNA JD; RODRIGUEZ CA

    2012-03-07T23:59:59.000Z

    Historically, high-level waste (HLW) glasses have been formulated with a low liquideus temperature (T{sub L}), or temperature at which the equilibrium fraction of spinel crystals in the melt is below 1 vol % (T{sub 0.01}), nominally below 1050 C. These constraints cannot prevent the accumulation of large spinel crystals in considerably cooler regions ({approx} 850 C) of the glass discharge riser during melter idling and significantly limit the waste loading, which is reflected in a high volume of waste glass, and would result in high capital, production, and disposal costs. A developed empirical model predicts crystal accumulation in the riser of the melter as a function of concentration of spinel-forming components in glass, and thereby provides guidance in formulating crystal-tolerant glasses that would allow high waste loadings by keeping the spinel crystals small and therefore suspended in the glass.

  1. Macromolecular Crystallization with Microfluidic Free-Interface Diffusion

    SciTech Connect (OSTI)

    Segelke, B

    2005-02-24T23:59:59.000Z

    Fluidigm released the Topaz 1.96 and 4.96 crystallization chips in the fall of 2004. Topaz 1.96 and 4.96 are the latest evolution of Fluidigm's microfluidics crystallization technologies that enable ultra low volume rapid screening for macromolecular crystallization. Topaz 1.96 and 4.96 are similar to each other but represent a major redesign of the Topaz system and have of substantially improved ease of automation and ease of use, improved efficiency and even further reduced amount of material needed. With the release of the new Topaz system, Fluidigm continues to set the standard in low volume crystallization screening which is having an increasing impact in the field of structural genomics, and structural biology more generally. In to the future we are likely to see further optimization and increased utility of the Topaz crystallization system, but we are also likely to see further innovation and the emergence of competing technologies.

  2. PLASTIC DEFORMATION OF CRYSTALS: ANALYTICAL AND COMPUTER SIMULATION STUDIES OF DISLOCATION GLIDE

    E-Print Network [OSTI]

    Altintas, Sabri

    2011-01-01T23:59:59.000Z

    in Rate Processes in Plastic Deformation of Materials, J. C.PLASTIC DEFORMATION OF CRYSTALS: ANALYTICAL AND COMPUTERCAPTIONS FIGURES - iii - PLASTIC DEFORMATION OF CRYSTALS:

  3. Pulsed pyroelectric crystal-powered gamma source

    SciTech Connect (OSTI)

    Chen, A. X.; Antolak, A. J.; Leung, K.-N.; Raber, T. N.; Morse, D. H. [Sandia National Laboratories, Livermore, CA 94550 (United States)

    2013-04-19T23:59:59.000Z

    A compact pulsed gamma generator is being developed to replace radiological sources used in commercial, industrial and medical applications. Mono-energetic gammas are produced in the 0.4 - 1.0 MeV energy range using nuclear reactions such as {sup 9}Be(d,n{gamma}){sup 10}B. The gamma generator employs an RF-driven inductively coupled plasma ion source to produce deuterium ion current densities up to 2 mA/mm{sup 2} and ampere-level current pulses can be attained by utilizing an array extraction grid. The extracted deuterium ions are accelerated to approximately 300 keV via a compact stacked pyroelectric crystal system and then bombard the beryllium target to generate gammas. The resulting microsecond pulse of gammas is equivalent to a radiological source with curie-level activity.

  4. Electrochemical system including lamella settler crystallizer

    DOE Patents [OSTI]

    Maimoni, Arturo (Orinda, CA)

    1988-01-01T23:59:59.000Z

    A crystallizer which incorporates a lamella settler and which is particularly applicable for use in batteries and power cells for electric vehicles or stationary applications. The lamella settler can be utilized for coarse particle separation or for agglomeration, and is particularly applicable to aluminum-air batteries or power cells for solving the hydrargillite (aluminum-hydroxide) removal problems from such batteries. This invention provides the advantages of very low energy consumption, turbulence, shear, cost and maintenance. Thus, due to the low shear and low turbulence of this invention, it is particularly effective in the control of aluminum hydroxide particle size distribution in the various sections of an aluminum-air system, as will as in other elecrochemical systems requiring separation for phases of different densities.

  5. Halide electroadsorption on single crystal surfaces

    SciTech Connect (OSTI)

    Ocko, B.M. [Brookhaven National Lab., Upton, NY (United States). Dept. of Physics; Wandlowski, T. [Univ. of Ulm (Germany). Dept. of Electrochemistry

    1997-07-01T23:59:59.000Z

    The structure and phase behavior of halides have been investigated on single crystals of Ag and Au using synchrotron x-ray scattering techniques. The adlayer coverages are potential dependent. For all halides studied the authors found that with increasing potential, at a critical potential, a disordered adlayer transforms into an ordered structure. Often these ordered phases are incommensurate and exhibit potential-dependent lateral separations (electrocompression). The authors have analyzed the electrocompression in terms of a model which includes lateral interactions and partial charge. A continuous compression is not observed for Br on Ag(100). Rather, they find that the adsorption is site-specific (lattice gas) in both the ordered and disordered phases. The coverage increases with increasing potential and at a critical potential the disordered phase transforms to a well-ordered commensurate structure.

  6. The Crystal Structure of Human Argonaute2

    SciTech Connect (OSTI)

    Schirle, Nicole T.; MacRae, Ian J. (Scripps)

    2012-07-18T23:59:59.000Z

    Argonaute proteins form the functional core of the RNA-induced silencing complexes that mediate RNA silencing in eukaryotes. The 2.3 angstrom resolution crystal structure of human Argonaute2 (Ago2) reveals a bilobed molecule with a central cleft for binding guide and target RNAs. Nucleotides 2 to 6 of a heterogeneous mixture of guide RNAs are positioned in an A-form conformation for base pairing with target messenger RNAs. Between nucleotides 6 and 7, there is a kink that may function in microRNA target recognition or release of sliced RNA products. Tandem tryptophan-binding pockets in the PIWI domain define a likely interaction surface for recruitment of glycine-tryptophan-182 (GW182) or other tryptophan-rich cofactors. These results will enable structure-based approaches for harnessing the untapped therapeutic potential of RNA silencing in humans.

  7. Recent results from the Crystal Ball

    SciTech Connect (OSTI)

    Porter, F.C.

    1981-09-01T23:59:59.000Z

    During the past year, the Crystal Ball experiment has continued the investigation of e/sup +/e/sup -/ interactions at SPEAR. In the course of the year, we have slightly more than doubled the available datasets at the J/psi (to 2.2 x 10/sup 6/ produced J/psi) and the psi' (to 1.8 x 10/sup 6/ produced psi') resonances, and have increased the data in the 5.2 to 7.4 GeV center-of-mass (E/sub c.m./) region. The present discussion is limited to recent results obtained with the J/psi and psi' datasets, primarily dealing with transitions among the charmonium bound states.

  8. Enhanced photoacoustic detection using photonic crystal substrate

    SciTech Connect (OSTI)

    Zhao, Yunfei; Liu, Kaiyang [Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States); McClelland, John [Ames Laboratory-USDOE, Ames, Iowa 50011 (United States); Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011 (United States); Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011 (United States); Lu, Meng, E-mail: menglu@iastate.edu [Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States); Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011 (United States)

    2014-04-21T23:59:59.000Z

    This paper demonstrates the enhanced photoacoustic sensing of surface-bound light absorbing molecules and metal nanoparticles using a one-dimensional photonic crystal (PC) substrate. The PC structure functions as an optical resonator at the wavelength where the analyte absorption is strong. The optical resonance of the PC sensor provides an intensified evanescent field with respect to the excitation light source and results in enhanced optical absorption by surface-immobilized samples. For the analysis of a light absorbing dye deposited on the PC surface, the intensity of photoacoustic signal was enhanced by more than 10-fold in comparison to an un-patterned acrylic substrate. The technique was also applied to detect gold nanorods and exhibited more than 40 times stronger photoacoustic signals. The demonstrated approach represents a potential path towards single molecule absorption spectroscopy with greater performance and inexpensive instrumentation.

  9. Crystal-Tolerant Glass Approach For Mitigation Of Crystal Accumulation In Continuous Melters Processing Radioactive Waste

    SciTech Connect (OSTI)

    Kruger, Albert A. [Department of Energy, Office of River Protection, Richland, Washington (United States); Rodriguez, Carmen P. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Lang, Jesse B. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Huckleberry, Adam R. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Matyas, Josef [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Owen, Antoinette T. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

    2012-08-28T23:59:59.000Z

    High-level radioactive waste melters are projected to operate in an inefficient manner as they are subjected to artificial constraints, such as minimum liquidus temperature (T{sub L}) or maximum equilibrium fraction of crystallinity at a given temperature. These constraints substantially limit waste loading, but were imposed to prevent clogging of the melter with spinel crystals [(Fe, Ni, Mn, Zn)(Fe, Cr){sub 2}O{sub 4}]. In the melter, the glass discharge riser is the most likely location for crystal accumulation during idling because of low glass temperatures, stagnant melts, and small diameter. To address this problem, a series of lab-scale crucible tests were performed with specially formulated glasses to simulate accumulation of spinel in the riser. Thicknesses of accumulated layers were incorporated into empirical model of spinel settling. In addition, T{sub L} of glasses was measured and impact of particle agglomeration on accumulation rate was evaluated. Empirical model predicted well the accumulation of single crystals and/or smallscale agglomerates, but, excessive agglomeration observed in high-Ni-Fe glass resulted in an under-prediction of accumulated layers, which gradually worsen over time as an increased number of agglomerates formed. Accumulation rate of ~14.9 +- 1 nm/s determined for this glass will result in ~26 mm thick layer in 20 days of melter idling.

  10. Solution-grown crystals for neutron radiation detectors, and methods of solution growth

    DOE Patents [OSTI]

    Zaitseva, Natalia P.; Hull, Giulia; Cherepy, Nerine J.; Payne, Stephen A.; Stoeffl, Wolfgang

    2012-06-26T23:59:59.000Z

    A method according to one embodiment includes growing an organic crystal from solution, the organic crystal exhibiting a signal response signature for neutrons from a radioactive source. A system according to one embodiment includes an organic crystal having physical characteristics of formation from solution, the organic crystal exhibiting a signal response signature for neutrons from a radioactive source; and a photodetector for detecting the signal response of the organic crystal. A method according to another embodiment includes growing an organic crystal from solution, the organic crystal being large enough to exhibit a detectable signal response signature for neutrons from a radioactive source. An organic crystal according to another embodiment includes an organic crystal having physical characteristics of formation from solution, the organic crystal exhibiting a signal response signature for neutrons from a radioactive source, wherein the organic crystal has a length of greater than about 1 mm in one dimension.

  11. Heterogeneity and dynamics in villin headpiece crystal structures

    SciTech Connect (OSTI)

    Meng, Jianmin; McKnight, Christopher James, E-mail: cjmck@bu.edu [Boston University School of Medicine (United States)

    2009-05-01T23:59:59.000Z

    New crystal structures of the well studied protein-folding model system villin headpiece in a new space group provide insights into the conformations available in the folded state. The villin headpiece domain (HP67) is the C-terminal F-actin-binding motif that confers F-actin-bundling activity to villin, a component of the actin bundles that support the brush-border microvilli. It has been investigated extensively by both experimental and theoretical measurements. Our laboratory, for example, has determined both its NMR and its crystal structures. This study presents the structures of HP67 and its pH-stabilized mutant (H41Y) in a different crystal form and space group. For both constructs, two molecules are found in each asymmetric unit in the new space group P6{sub 1}. While one of the two structures (Mol A) is structurally similar to our previously determined structure (Mol X), the other (Mol B) has significant deviations, especially in the N-terminal subdomain, where lattice contacts do not appear to contribute to the difference. In addition, the structurally most different crystal structure, Mol B, is actually closer to the averaged NMR structure. Harmonic motions, as suggested by the B-factor profiles, differ between these crystal structures; crystal structures from the same space group share a similar pattern. Thus, heterogeneity and dynamics are observed in different crystal structures of the same protein even for a protein as small as villin headpiece.

  12. Entanglement Generation Using Discrete Solitons in Coulomb Crystals

    E-Print Network [OSTI]

    H. Landa; A. Retzker; T. Schaetz; B. Reznik

    2014-07-31T23:59:59.000Z

    Laser cooled and trapped ions can crystallize and feature discrete solitons, that are nonlinear, topologically-protected configurations of the Coulomb crystal. Such solitons, as their continuum counterparts, can move within the crystal, while their discreteness leads to the existence of a gap-separated, spatially-localized motional mode of oscillation above the spectrum. Suggesting that these unique properties of discrete solitons can be used for generating entanglement between different sites of the crystal, we study a detailed proposal in the context of state-of-the-art experimental techniques. We analyze the interaction of periodically-driven planar ion crystals with optical forces, revealing the effects of micromotion in radio-frequency traps inherent to such structures, as opposed to linear ion chains. The proposed method requires Doppler cooling of the crystal and sideband cooling of the soliton's localized modes alone. Since the gap separation of the latter is nearly independent of the crystal size, this approach could be particularly useful for producing entanglement and studying system-environment interactions in large, two- and possibly three-dimensional systems.

  13. Single crystal Processing and magnetic properties of gadolinium nickel

    SciTech Connect (OSTI)

    Shreve, Andrew John [Ames Laboratory

    2012-11-02T23:59:59.000Z

    GdNi is a rare earth intermetallic material that exhibits very interesting magnetic properties. Spontaneous magnetostriction occurs in GdNi at T{sub C}, on the order of 8000ppm strain along the c-axis and only until very recently the mechanism causing this giant magnetostriction was not understood. In order to learn more about the electronic and magnetic structure of GdNi, single crystals are required for anisotropic magnetic property measurements. Single crystal processing is quite challenging for GdNi though since the rare-earth transition-metal composition yields a very reactive intermetallic compound. Many crystal growth methods are pursued in this study including crucible free methods, precipitation growths, and specially developed Bridgman crucibles. A plasma-sprayed Gd{sub 2}O{sub 3} W-backed Bridgman crucible was found to be the best means of GdNi single crystal processing. With a source of high-quality single crystals, many magnetization measurements were collected to reveal the magnetic structure of GdNi. Heat capacity and the magnetocaloric effect are also measured on a single crystal sample. The result is a thorough report on high quality single crystal processing and the magnetic properties of GdNi.

  14. Optical-diffraction method for determining crystal orientation

    DOE Patents [OSTI]

    Sopori, B.L.

    1982-05-07T23:59:59.000Z

    Disclosed is an optical diffraction technique for characterizing the three-dimensional orientation of a crystal sample. An arbitrary surface of the crystal sample is texture etched so as to generate a pseudo-periodic diffraction grating on the surface. A laser light beam is then directed onto the etched surface, and the reflected light forms a farfield diffraction pattern in reflection. Parameters of the diffraction pattern, such as the geometry and angular dispersion of the diffracted beam are then related to grating shape of the etched surface which is in turn related to crystal orientation. This technique may be used for examining polycrystalline silicon for use in solar cells.

  15. An optical surface resonance may render photonic crystals ineffective

    E-Print Network [OSTI]

    F. García-Santamaría; Erik C. Nelson; P. V. Braun

    2007-06-28T23:59:59.000Z

    In this work we identify and study the presence of extremely intense surface resonances that frustrate the coupling of photons into a photonic crystal over crucial energy ranges. The practical utility of photonic crystals demands the capability to exchange photons with the external medium, therefore, it is essential to understand the cause of these surface resonances and a route to their elimination. We demonstrate that by modifying the surface geometry it is possible to tune the optical response or eliminate the resonances to enable full exploitation of the photonic crystal.

  16. Generation and manipulation of nonclassical light using photonic crystals

    E-Print Network [OSTI]

    Jelena Vuckovic; Dirk Englund; David Fattal; Edo Waks; Yoshihisa Yamamoto

    2005-10-07T23:59:59.000Z

    Photonic crystal cavities can localize light into nanoscale volumes with high quality factors. This permits a strong interaction between light and matter, which is important for the construction of classical light sources with improved properties (e.g., low threshold lasers) and of nonclassical light sources (such as single and entangled photon sources) that are crucial pieces of hardware of quantum information processing systems. This article will review some of our recent experimental and theoretical results on the interaction between single quantum dots and photonic crystal cavity fields, and on the integration of multiple photonic crystal devices into functional circuits for quantum information processing.

  17. Methods of making composite optical devices employing polymer liquid crystal

    DOE Patents [OSTI]

    Jacobs, S.D.; Marshall, K.L.; Cerqua, K.A.

    1991-10-08T23:59:59.000Z

    Composite optical devices are disclosed using polymer liquid crystal materials both as optical and adhesive elements. The devices are made by assembling a heated polymer liquid crystal compound, while in a low viscosity form between optically transparent substrates. The molecules of the polymer are oriented, while in the liquid crystalline state and while above the glass transition temperature (T[sub g]) of the polymer, to provide the desired optical effects, such as polarization, and selective reflection. The liquid crystal polymer cements the substrates together to form an assembly providing the composite optical device. 7 figures.

  18. Methods of making composite optical devices employing polymer liquid crystal

    DOE Patents [OSTI]

    Jacobs, Stephen D. (Pittsford, NY); Marshall, Kenneth L. (Henrietta, NY); Cerqua, Kathleen A. (Fairport, NY)

    1991-01-01T23:59:59.000Z

    Composite optical devices using polymer liquid crystal materials both as optical and adhesive elements. The devices are made by assembling a heated polymer liquid crystal compound, while in a low viscosity form between optically transparent substrates. The molecules of the polymer are oriented, while in the liquid crystalline state and while above the glass transition temperature (T.sub.g) of the polymer, to provide the desired optical effects, such as polarization, and selective reflection. The liquid crystal polymer cements the substrates together to form an assembly providing the composite optical device.

  19. Epitaxial electrodeposition of freestanding large area single crystal substrates

    SciTech Connect (OSTI)

    Shin, Jae Wook; Standley, Adam; Chason, Eric [Brown University, Box D, Providence, Rhode Island 02912 (United States)

    2007-06-25T23:59:59.000Z

    The authors report on a method for producing freestanding single crystal metal films over large areas using electrodeposition and selective etching. The method can be turned into an inexpensive continuous process for making long ribbons or a large area of single crystal films. Results from a 5x5 mm{sup 2} Ni single crystal film using electron backscattering pattern pole figures and x-ray diffraction demonstrate that the quality of material produced is equivalent to the initial substrate without annealing or polishing.

  20. Nexus Energy Center Unveils Energy-Efficient Tiny Home | Department...

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

    TRES Project has spray-foam insulation, ENERGY STAR qualified windows, and light-emitting diode (LED) lights. Solar panels will eventually be installed as well. Nexus is...

  1. XenoTiny: Emulating Wireless Sensor Networks on Xen

    E-Print Network [OSTI]

    Sventek, J.; Maclean, A.; McIlroy, R.

    Sventek,J. Maclean,A. McIlroy,R. Milos,G. DCS Technical Report Series pp 1-10 Dept of Computing Science, University of Glasgow

  2. Good hair day: New technique grows tiny 'hairy' materials at...

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

    a lot of surface area will speed the process along. (For example, grinding coffee beans gives the coffee more flavor than soaking whole beans in water.) Micro-size hairs can...

  3. Electrofuels: Tiny Organisms Making a Big Impact | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onYouTube YouTube Note: Since the YouTube|6721 Federal Register / Vol.6:Energy|Electrifying Your Drive

  4. Manipulating X-rays with Tiny Mirrors | Argonne National Laboratory

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

    for controlling X-rays. MEMS, or microelectromechanical systems, allow shrinking the optics to the microscale creating ultrafast devices for reflecting X-rays at precise times...

  5. Electrofuels: Tiny Organisms Making a Big Impact | Department of Energy

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directed off Energy.gov. Are you sure you want toworldPowerHome | Documents

  6. Photo of the Week: Tiny Batteries | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onYouTube YouTube Note: Since the.pdfBreaking ofOilNEWResponse(Expired)of Energy Photothe Mojave DesertThe ZPhoto of

  7. Tamil Nadu Small and Tiny Industries Association TANSTIA | Open Energy

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere IRaghuraji Agro Industries PvtStratosolar Jump to:Holdings Co08.0 -TEEMPTallmadge, Ohio:Tamiami,

  8. Measuring Tiny Waves with High Power Particle Beams | Princeton Plasma

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home andDisposition |MaterialsMatt10Laser,

  9. Imager Spots and Samples Tiny Tumors | Jefferson Lab

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh School footballHydrogenIT |Hot SpringsemployedImager Spots and Samples

  10. Sandia Energy - Sandia Labs Harnesses the Sun's Energy with Tiny

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiationImplementing Nonlinear757Kelley RuehlReportPeterWave-Energy

  11. Tiny travelers from deep space could assist in healing Fukushima's

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening a solidSynthesis ofwasSynchrotronNanoDays at Bradbury

  12. The crystal structure of {pi}-ErBO{sub 3}: New single-crystal data for an old problem

    SciTech Connect (OSTI)

    Pitscheider, Almut [Institut fuer Allgemeine, Anorganische und Theoretische Chemie, Leopold-Franzens-Universitaet Innsbruck, Innrain 52a, A-6020 Innsbruck (Austria); Kaindl, Reinhard [Institut fuer Mineralogie und Petrographie, Leopold-Franzens-Universitaet Innsbruck, Innrain 52, A-6020 Innsbruck (Austria); Oeckler, Oliver [Department Chemie, Ludwig-Maximilians-Universitaet Muenchen, Butenandtstrasse 5-13, D-81377 Muenchen (Germany); Huppertz, Hubert, E-mail: Hubert.Huppertz@uibk.ac.a [Institut fuer Allgemeine, Anorganische und Theoretische Chemie, Leopold-Franzens-Universitaet Innsbruck, Innrain 52a, A-6020 Innsbruck (Austria)

    2011-01-15T23:59:59.000Z

    Single crystals of the orthoborate {pi}-ErBO{sub 3} were synthesized from Er{sub 2}O{sub 3} and B{sub 2}O{sub 3} under high-pressure/high-temperature conditions of 2 GPa and 800 {sup o}C in a Walker-type multianvil apparatus. The crystal structure was determined on the basis of single-crystal X-ray diffraction data, collected at room temperature. The title compound crystallizes in the monoclinic pseudowollastonite-type structure, space group C2/c, with the lattice parameters a=1128.4(2) pm, b=652.6(2) pm, c=954.0(2) pm, and {beta}=112.8(1){sup o} (R{sub 1}=0.0124 and wR{sub 2}=0.0404 for all data). -- graphical abstract: The first satisfying single-crystal structure determination of {pi}-ErBO{sub 3} sheds light on the extensively discussed structure of {pi}-orthoborates. The application of light pressure during the solid state synthesis yielded in high-quality crystals, due to pressure-induced crystallization. Research highlights: {yields} High-quality single crystals of {pi}-ErBO{sub 3} were prepared via high-pressure-induced crystallization. {yields} At least five different space groups for the rare-earth {pi}-orthoborates are reported. {yields} {pi}-ErBO{sub 3} is isotypic to the pseudowollastonite-type CaSiO{sub 3}. {yields} Remaining ambiguities regarding the structure of the rare-earth {pi}-orthoborates are resolved.

  13. Crystal-melt interfacial free energies of hard-dumbbell systems Yan Mu and Xueyu Song

    E-Print Network [OSTI]

    Song, Xueyu

    Crystal-melt interfacial free energies of hard-dumbbell systems Yan Mu and Xueyu Song Department September 2006; published 29 September 2006 The crystal-melt interfacial free energies of different crystal that for the plastic crystal phase, the interfacial free energies decrease as the reduced bond length L* increases

  14. LIQUID CRYSTAL THERMOGRAPHY ON THE FLUID SOLID INTERFACE OF ROTATING SYSTEMS

    E-Print Network [OSTI]

    Camci, Cengiz

    = Aluminum c = centrifugal lc = liquid crystal o = aerodynamic wall friction related p = at constant pressu

  15. acid dhsa crystals: Topics by E-print Network

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

    to Characterise Micro-swimmers CERN Preprints Summary: We study the behaviour of hydrogen-peroxide-fuelled self-propelled Janus colloids in a 2D colloidal crystal matrix. The...

  16. aluminum-induced crystallization comparison: Topics by E-print...

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

    of charges on the particles is studied. S. Kondrat; M. Bier; L. Harnau 2010-04-15 413 Giant Lamb Shift in Photonic Crystals Quantum Physics (arXiv) Summary: We obtain a general...

  17. Curvature-directed Crystallization of Polymer Dielectrics in Nanopores 

    E-Print Network [OSTI]

    Reid, Dariya

    2013-11-26T23:59:59.000Z

    The formation of isotactic poly(propylene) (iPP) and polycarbonate (PC) nanowires of tunable diameter was demonstrated by melt-wetting the polymer into nanoporous anodic alumina. The crystallization process was analyzed using differential scanning...

  18. Design of polymeric substrates for controlled molecular crystallization

    E-Print Network [OSTI]

    Diao, Ying, Ph.D. Massachusetts Institute of Technology

    2012-01-01T23:59:59.000Z

    It is essential to control crystallization in many areas of science and technology, such as the production of pharmaceuticals, pigments, concrete, semiconductors, as well as the formation of biominerals. In most practical ...

  19. Reversible Attraction-Mediated Colloidal Crystallization on Patterned Substrates

    E-Print Network [OSTI]

    Fernandes, Gregory

    2009-05-15T23:59:59.000Z

    In this dissertation we used tunable particle-particle and particle-substrate attraction to achieve reversible two-dimensional crystallization of colloids on homogeneous and patterned substrates. Total internal reflection and video microscopy...

  20. Terahertz Room-Temperature Photonic Crystal Nanocavity Laser

    E-Print Network [OSTI]

    Dirk Englund; Hatice Altug; Ilya Fushman; Jelena Vuckovic

    2007-06-21T23:59:59.000Z

    We describe an efficient surface-passivated photonic crystal nanocavity laser, demonstrating room-temperature operation with 3-ps total pulse duration (detector response limited) and low-temperature operation with ultra-low-threshold near 9uW.

  1. Superconducting Proximity Effect in Single-Crystal Nanowires 

    E-Print Network [OSTI]

    Liu, Haidong

    2010-07-14T23:59:59.000Z

    This dissertation describes experimental studies of the superconducting proximity effect in single-crystal Pb, Sn, and Zn nanowires of lengths up to 60 um, with both ends of the nanowires in contact with macroscopic electrodes that are either...

  2. Synthesis and physical characterization of thermoelectric single crystals

    E-Print Network [OSTI]

    Porras Pérez Guerrero, Juan Pablo

    2012-01-01T23:59:59.000Z

    There is much current interest in thermoelectric devices for sustainable energy. This thesis describes a research project on the synthesis and physical characterization of thermoelectric single crystals. 1In?Se?-[delta] ...

  3. Melt generation, crystallization, and extraction beneath segmented oceanic transform faults

    E-Print Network [OSTI]

    Gregg, Patricia M.

    We examine mantle melting, fractional crystallization, and melt extraction beneath fast slipping, segmented oceanic transform fault systems. Three-dimensional mantle flow and thermal structures are calculated using a ...

  4. Crystallization process development and spherical agglomerates for pharmaceutical processing applications

    E-Print Network [OSTI]

    Quon, Justin (Justin Louie)

    2013-01-01T23:59:59.000Z

    The control of crystallization steps is essential in the production of many materials in the pharmaceutical, materials, and chemical industries. Additionally, due to increasing costs of research and development, reductions ...

  5. The Gamma Intensity Monitor at the Crystal-Barrel-Experiment

    E-Print Network [OSTI]

    McGehee, William R

    2008-01-01T23:59:59.000Z

    This thesis details the motivation, design, construction, and testing of the Gamma Intensity Monitor (GIM) for the Crystal-Barrel-Experiment at the Universität Bonn. The CB-ELSA collaboration studies the baryon excitation ...

  6. Constitutive modeling of creep of single crystal superalloys

    E-Print Network [OSTI]

    Prasad, Sharat Chand

    2006-10-30T23:59:59.000Z

    In this work, a constitutive theory is developed, within the context of continuum mechanics, to describe the creep deformation of single crystal superalloys. The con- stitutive model that is developed here is based on the fact that as bodies deform...

  7. Enhancing cholesteric liquid crystal laser performance using a cholesteric reflector

    E-Print Network [OSTI]

    Wu, Shin-Tson

    laser based on a free- standing film of photo polymerized cholesteric liquid crystal," Appl. Phys. Lett as an optic fiber-based temperature sensor," Appl. Phys. Lett. 85, 2691-2693 (2004). 15. Y. Huang, Y. Zhou

  8. Enhanced photodetection in graphene-integrated photonic crystal cavity

    E-Print Network [OSTI]

    Shiue, Ren-Jye

    We demonstrate the controlled enhancement of photoresponsivity in a graphene photodetector by coupling to slow light modes in a long photonic crystal linear defect cavity. Near the Brillouin zone (BZ) boundary, spectral ...

  9. Electro-optical Modulation in Graphene Integrated Photonic Crystal Nanocavities

    E-Print Network [OSTI]

    Gan, Xuetao

    We demonstrate high-contrast electro-optic modulation in a graphene integrated photonic crystal nanocavity, providing a modulation depth of more than 10 dB at telecom wavelengths. This work shows the feasibility of ...

  10. GaBo{sub 3} crystal growth from flux

    SciTech Connect (OSTI)

    Rudenko, V.V. [Institute of Physics, Krasnoyarsk (Russian Federation)

    1995-03-01T23:59:59.000Z

    Synthesis of the chemical compound GaBO{sub 3} was first reported in paper, and the crystallographic determination of its structure and unit cell parameters was presented in paper. The chemical compound GaBO{sub 3} crystallizes in a calcite structure type with the hexagonal unit cell Parameters a{sub H} = 4.568 and c{sub H} = 14.18 {Angstrom}. GaBO{sub 3} crystals in the form of (111) hexagonal plates were grown from the solvent B{sub 2}O{sub 3}-Bi{sub 2}O{sub 3} by the method of sponvineous crystallization. That technique was hard to reproduce, however. We decided to grow a GaBO{sub 3} crystal as an object for possible studies of various physical properties. 8 refs., 2 figs.

  11. Classical crystal formation of dipoles in two dimensions

    E-Print Network [OSTI]

    Hansen, K K; Jensen, A S; Zinner, N T

    2015-01-01T23:59:59.000Z

    We consider a two-dimensional layer of dipolar particles at zero temperature in the regime of strong dipole moments. Here we can describe the system using classical methods and determine the crystal structure that minimizes the total energy. The dipoles are assumed to be aligned by an external field and we consider different orientations of the dipolar moments with respect to the two-dimensional plane of motion. We observe that when the orientation angle changes away from perpendicular and towards the plane, the crystal structure will change from a hexagonal form to one that has the dipoles sitting in equidistant rows, i.e. a striped configuration. In addition to calculating the crystal unit cell, we also consider the phonon spectrum and the speed of sound. As the orientation changes away from perpendicular the phonon spectrum develops local minima that are a result of the deformation to the crystal structure.

  12. Materials for freeform fabrication of GHz tunable dielectric photonic crystals.

    SciTech Connect (OSTI)

    Niehaus, Michael Keith; Lewis, Jennifer A. (University of Illinois, Urbana, IL); Smay, James Earl; Clem, Paul Gilbert; Lin, Shawn-Yu; Cesarano, Joseph, III (,; ); Carroll, James F.

    2003-01-01T23:59:59.000Z

    Photonic crystals are of interest for GHz transmission applications, including rapid switching, GHz filters, and phased-array technology. 3D fabrication by Robocasting enables moldless printing of high solid loading slurries into structures such as the ''woodpile'' structures used to fabricate dielectric photonic band gap crystals. In this work, tunable dielectric materials were developed and printed into woodpile structures via solid freeform fabrication (SFF) toward demonstration of tunable photonic crystals. Barium strontium titanate ceramics possess interesting electrical properties including high permittivity, low loss, and high tunability. This paper discusses the processing route and dielectric characterization of (BaxSr1-XTiO3):MgO ceramic composites, toward fabrication of tunable dielectric photonic band gap crystals.

  13. Novel advancements in nanofabrication for photonic crystal applications

    E-Print Network [OSTI]

    Cheong, Lin Lee

    2013-01-01T23:59:59.000Z

    The progress of large-area 2D- and 3D-photonic crystals (PCs) at optical and near infra-red frequencies has been limited by fabrication challenges. Periodic nanostructures must be patterned in high-index and crystalline ...

  14. A microprocessor driven liquid crystal graphics display for aircraft use

    E-Print Network [OSTI]

    Marzke, Lee Howard

    1984-01-01T23:59:59.000Z

    A complete graphics system for use in modular avionics is built around a liquid crystal flat panel display. Screen refresh is handled by display controller that provides a bit mapped representation of the display in RAM. ...

  15. Jefferson Lab Builds First Single Crystal Single Cell Accelerating...

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

    Single Cell Cavity This single cell cavity was made from a single crystal of niobium. Made in the same shape as the low-loss design proposed as an improvement to the baseline for...

  16. Broadband super-collimation in a hybrid photonic crystal structure

    E-Print Network [OSTI]

    Hamam, Rafif E.

    We propose a two dimensional (2D) photonic crystal (PhC) structure that supports super-collimation over a large frequency range (over 4 times that of a traditional square lattice of holes). We theoretically and numerically ...

  17. Molecular simulation of crystal growth in alkane and polyethylene melts

    E-Print Network [OSTI]

    Waheed, Numan

    2005-01-01T23:59:59.000Z

    Molecular simulation has become a very powerful tool for understanding the process of polymer crystallization. By using carefully constructed simulations, one can independently observe the two phenomena responsible for ...

  18. Invariant patterns in crystal lattices: Implications for protein folding algorithms

    SciTech Connect (OSTI)

    HART,WILLIAM E.; ISTRAIL,SORIN

    2000-06-01T23:59:59.000Z

    Crystal lattices are infinite periodic graphs that occur naturally in a variety of geometries and which are of fundamental importance in polymer science. Discrete models of protein folding use crystal lattices to define the space of protein conformations. Because various crystal lattices provide discretizations of the same physical phenomenon, it is reasonable to expect that there will exist invariants across lattices related to fundamental properties of the protein folding process. This paper considers whether performance-guaranteed approximability is such an invariant for HP lattice models. The authors define a master approximation algorithm that has provable performance guarantees provided that a specific sublattice exists within a given lattice. They describe a broad class of crystal lattices that are approximable, which further suggests that approximability is a general property of HP lattice models.

  19. Carbon Nanotube-Reinforced Thermotropic Liquid Crystal Polymer Nanocomposites

    E-Print Network [OSTI]

    Kim, Jun Young

    This paper focuses on the fabrication via simple melt blending of thermotropic liquid crystal polyester (TLCP) nanocomposites reinforced with a very small quantity of modified carbon nanotube (CNT) and the unique effects ...

  20. Superconducting Proximity Effect in Single-Crystal Nanowires

    E-Print Network [OSTI]

    Liu, Haidong

    2010-07-14T23:59:59.000Z

    This dissertation describes experimental studies of the superconducting proximity effect in single-crystal Pb, Sn, and Zn nanowires of lengths up to 60 um, with both ends of the nanowires in contact with macroscopic electrodes that are either...

  1. al single crystal: Topics by E-print Network

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

    14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Low-Leakage Superconducting Tunnel Junctions with a Single-Crystal Al2O3 Barrier* Computer Technologies and...

  2. al single crystals: Topics by E-print Network

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

    14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Low-Leakage Superconducting Tunnel Junctions with a Single-Crystal Al2O3 Barrier* Computer Technologies and...

  3. Healing of defects in a two-dimensional granular crystal

    E-Print Network [OSTI]

    Rice, Marie C

    2014-01-01T23:59:59.000Z

    Using a macroscopic analog for a two dimensional hexagonal crystal, we perform an experimental investigation of the self-healing properties of circular grain defects with an emphasis on defect orientation. A circular grain ...

  4. A machine learning approach to crystal structure prediction

    E-Print Network [OSTI]

    Fischer, Christopher Carl

    2007-01-01T23:59:59.000Z

    This thesis develops a machine learning framework for predicting crystal structure and applies it to binary metallic alloys. As computational materials science turns a promising eye towards design, routine encounters with ...

  5. atomic resolution crystal: Topics by E-print Network

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

    18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Crystal structure retrieval by maximum entropy analysis of atomic resolution incoherent images Materials Science Websites...

  6. angstrom resolution crystal: Topics by E-print Network

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

    Muller, David A; 10.1103PhysRevB.86.195415 2012-01-01 5 Crystal structure retrieval by maximum entropy analysis of atomic resolution incoherent images Materials Science Websites...

  7. On band gaps in photonic crystal fibers

    E-Print Network [OSTI]

    Shane Cooper; Ilia Kamotski; Valery Smyshlyaev

    2014-11-02T23:59:59.000Z

    We consider the Maxwell's system for a periodic array of dielectric `fibers' embedded into a `matrix', with respective electric permittivities $\\epsilon_0$ and $\\epsilon_1$, which serves as a model for cladding in photonic crystal fibers (PCF). The interest is in describing admissible and forbidden (gap) pairs $(\\omega,k)$ of frequencies $\\omega$ and propagation constants $k$ along the fibers, for a Bloch wave solution on the cross-section. We show that, for "pre-critical" values of $k(\\omega)$ i.e. those just below $\\omega (\\min\\{\\epsilon_0,\\epsilon_1\\}\\mu)^{1/2}$ (where $\\mu$ is the magnetic permeability assumed constant for simplicity), the coupling specific to the Maxwell's systems leads to a particular partially degenerating PDE system for the axial components of the electromagnetic field. Its asymptotic analysis allows to derive the limit spectral problem where the fields are constrained in one of the phases by Cauchy-Riemann type relations. We prove related spectral convergence. We finally give some examples, in particular of small size "arrow" fibers ($\\epsilon_0>\\epsilon_1$) where the existence of the gaps near appropriate "micro-resonances" is demonstrated by a further asymptotic analysis.

  8. Analogy between free electron laser and channeling by crystal planes

    E-Print Network [OSTI]

    X. Artru

    2005-03-21T23:59:59.000Z

    The trapping of electrons in the ponderomotive potential wells, which governs a free electron laser or inverse free electron laser at high gain, is analogous to the channeling of charged particles by atomic planes of a crystal. A bent crystal is analogous to a period-tapered free electron laser. This analogy is different from the well-known one between channeling and undulator radiations.

  9. Use of a photonic crystal for optical amplifier gain control

    DOE Patents [OSTI]

    Lin, Shawn-Yu (Albuquerque, NM); Fleming, James G. (Albuquerque, NM); El-Kady, Ihab (Albuquerque, NM)

    2006-07-18T23:59:59.000Z

    An optical amplifier having a uniform gain profile uses a photonic crystal to tune the density-of-states of a gain medium so as to modify the light emission rate between atomic states. The density-of-states of the gain medium is tuned by selecting the size, shape, dielectric constant, and spacing of a plurality of microcavity defects in the photonic crystal. The optical amplifier is particularly useful for the regeneration of DWDM signals in long optical fibers.

  10. Growth and characterization of lithium yttrium borate single crystals

    SciTech Connect (OSTI)

    Singh, A. K.; Singh, S. G.; Tyagi, M.; Desai, D. G.; Sen, Shashwati [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai- 400085 (India)

    2014-04-24T23:59:59.000Z

    Single crystals of 0.1% Ce doped Li{sub 6}Y(BO{sub 3}){sub 3} have been grown using the Czochralski technique. The photoluminescence study of these crystals shows a broad emission at ? 420 nm corresponding to Ce{sub 3+} emission from 5d?4f energy levels. The decay profile of this emission shows a fast response of ? 28 ns which is highly desirable for detector applications.

  11. Liquid crystal devices especially for use in liquid crystal point diffraction interferometer systems

    DOE Patents [OSTI]

    Marshall, Kenneth L. (Rochester, NY)

    2009-02-17T23:59:59.000Z

    Liquid crystal point diffraction interferometer (LCPDI) systems that can provide real-time, phase-shifting interferograms that are useful in the characterization of static optical properties (wavefront aberrations, lensing, or wedge) in optical elements or dynamic, time-resolved events (temperature fluctuations and gradients, motion) in physical systems use improved LCPDI cells that employ a "structured" substrate or substrates in which the structural features are produced by thin film deposition or photo resist processing to provide a diffractive element that is an integral part of the cell substrate(s). The LC material used in the device may be doped with a "contrast-compensated" mixture of positive and negative dichroic dyes.

  12. Phonons in a one-dimensional microfluidic crystal

    E-Print Network [OSTI]

    Tsevi Beatus; Tsvi Tlusty; Roy Bar-Ziv

    2010-08-06T23:59:59.000Z

    The development of a general theoretical framework for describing the behaviour of a crystal driven far from equilibrium has proved difficult1. Microfluidic crystals, formed by the introduction of droplets of immiscible fluid into a liquid-filled channel, provide a convenient means to explore and develop models to describe non-equilibrium dynamics2, 3, 4, 5, 6, 7, 8, 9, 10, 11. Owing to the fact that these systems operate at low Reynolds number (Re), in which viscous dissipation of energy dominates inertial effects, vibrations are expected to be over-damped and contribute little to their dynamics12, 13, 14. Against such expectations, we report the emergence of collective normal vibrational modes (equivalent to acoustic 'phonons') in a one-dimensional microfluidic crystal of water-in-oil droplets at Reapprox10-4. These phonons propagate at an ultra-low sound velocity of approx100 mum s-1 and frequencies of a few hertz, exhibit unusual dispersion relations markedly different to those of harmonic crystals, and give rise to a variety of crystal instabilities that could have implications for the design of commercial microfluidic systems. First-principles theory shows that these phonons are an outcome of the symmetry-breaking flow field that induces long-range inter-droplet interactions, similar in nature to those observed in many other systems including dusty plasma crystals15, 16, vortices in superconductors17, 18, active membranes19 and nucleoprotein filaments20.

  13. SINGLE CRYSTAL NIOBIUM TUBES FOR PARTICLE COLLIDERS ACCELERATOR CAVITIES

    SciTech Connect (OSTI)

    MURPHY, JAMES E [University of Nevada, Reno] [University of Nevada, Reno

    2013-02-28T23:59:59.000Z

    The objective of this research project is to produce single crystal niobium (Nb) tubes for use as particle accelerator cavities for the Fermi laboratory’s International Linear Collider project. Single crystal Nb tubes may have superior performance compared to a polycrystalline tubes because the absence of grain boundaries may permit the use of higher accelerating voltages. In addition, Nb tubes that are subjected to the high temperature, high vacuum crystallization process are very pure and well annealed. Any impurity with a significantly higher vapor pressure than Nb should be decreased by the relatively long exposure at high temperature to the high vacuum environment. After application of the single crystal process, the surfaces of the Nb tubes are bright and shiny, and the tube resembles an electro polished Nb tube. For these reasons, there is interest in single crystal Nb tubes and in a process that will produce single crystal tubes. To convert a polycrystalline niobium tube into a single crystal, the tube is heated to within a few hundred ?C of the melting temperature of niobium, which is 2477 ?C. RF heating is used to rapidly heat the tube in a narrow zone and after reaching the operating temperature, the hot zone is slowly passed along the length of the tube. For crystallization tests with Nb tubes, the traverse rate was in the range of 1-10 cm per hour. All the crystallization tests in this study were performed in a water-cooled, stainless steel chamber under a vacuum of 5 x10-6 torr or better. In earliest tests of the single crystal growth process, the Nb tubes had an OD of 1.9 cm and a wall thickness of 0.15 mm. With these relatively small Nb tubes, the single crystal process was always successful in producing single crystal tubes. In these early tests, the operating temperature was normally maintained at 2200 ?C, and the traverse rate was 5 cm per hour. In the next test series, the Nb tube size was increased to 3.8 cm OD and the wall thickness was increased 0.18 mm and eventually to 0.21 mm. Again, with these larger tubes, single crystal tubes were usually produced by the crystallization process. The power supply was generally operated at full output during these tests, and the traverse rate was 5 cm per hour. In a few tests, the traverse rate was increased to 10 cm per hour, and at the faster traverse rate, single crystal growth was not achieved. In these tests with a faster traverse rate, it was thought that the tube was not heated to a high enough temperature to achieve single crystal growth. In the next series of tests, the tube OD was unchanged at 3.8 cm and the wall thickness was increased to 0.30 mm. The increased wall thickness made it difficult to reach an operating temperature above 2,000 ?C, and although the single crystal process caused a large increase in the crystal grains, no single crystal tubes were produced. It was assumed that the operating temperature in these tests was not high enough to achieve single crystal growth. In FY 2012, a larger power supply was purchased and installed. With the new power supply, temperatures above the melting point of Nb were easily obtained regardless of the tube thickness. A series of crystallization tests was initiated to determine if indeed the operating temperature of the previous tests was too low to achieve single crystal growth. For these tests, the Nb tube OD remained at 3.8 cm and the wall thickness was 0.30 mm. The first test had an operating temperature of 2,000 ?C. and the operating temperature was increased by 50 ?C increments for each successive test. The final test was very near the Nb melting temperature, and indeed, the Nb tube eventually melted in the center of the tube. These tests showed that higher temperatures did yield larger grain sizes if the traverse rate was held constant at 5 cm per hour, but no single crystal tubes were produced even at the highest operating temperature. In addition, slowing the traverse rate to as low as 1 cm per hour did not yield a single crystal tube regardless of operating temperature. At this time, it

  14. Crystallizing hard-sphere glasses by doping with active particles

    E-Print Network [OSTI]

    Ran Ni; Martien A. Cohen Stuart; Marjolein Dijkstra; Peter G. Bolhuis

    2014-08-25T23:59:59.000Z

    Crystallization and vitrification are two different routes to form a solid. Normally these two processes suppress each other, with the glass transition preventing crystallization at high density (or low temperature). This is even true for systems of colloidal hard spheres, which are commonly used as building blocks for novel functional materials with potential applications, e.g. photonic crystals. By performing Brownian dynamics simulations of glassy systems consisting of mixtures of active and passive hard spheres, we show that the crystallization of such hard-sphere glasses can be dramatically promoted by doping the system with small amounts of active particles. Surprisingly, even hard-sphere glasses of packing fraction up to $\\phi = 0.635$ crystallize, which is around $0.5\\%$ below the random close packing at $\\phi \\simeq 0.64$. Our results suggest a novel way of fabricating crystalline materials from (colloidal) glasses. This is particularly important for materials that get easily kinetically trapped in glassy states, and crystal nucleation hardly occurs.

  15. Photorefractivity in polymer-stabilized nematic liquid crystals

    SciTech Connect (OSTI)

    Wiederrecht, G.P. [Argonne National Lab., IL (United States). Chemistry Div.; Wasielewski, M.R. [Argonne National Lab., IL (United States). Chemistry Div.]|[Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry

    1998-07-01T23:59:59.000Z

    Polymer-stabilized liquid crystals, consisting of low concentrations of a polymeric electron acceptor, are shown to exhibit significantly enhanced photorefractive properties. The charge generation and transport properties of these composite systems are strongly modified from nematic liquid crystals doped with electron donors and acceptors. The new composites are produced by polymerizing a small quantity of a 1,4:5,8-naphthalenediimide electron acceptor functionalized with an acrylate group in an aligned nematic liquid crystal. Photopolymerization creates an anisotropic gel-like medium in which the liquid crystal is free to reorient in the presence of a space charge field, while maintaining charge trapping sites in the polymerized regions of the material. The presence of these trapping sites results in the observation of longer lived, higher resolution holographic gratings in the polymer-stabilized liquid crystals than observed in nematic liquid crystals alone. These gratings display Bragg regime diffraction. Asymmetric beam coupling, photo-conductivity, and four-wave mixing experiments are performed to characterize the photophysics of these novel materials.

  16. Radioactive contamination of ZnWO4 crystal scintillators

    E-Print Network [OSTI]

    P. Belli; R. Bernabei; F. Cappella; R. Cerulli; F. A. Danevich; A. M. Dubovik; S. d'Angelo; E. N. Galashov; B. V. Grinyov; A. Incicchitti; V. V. Kobychev; M. Laubenstein; L. L. Nagornaya; F. Nozzoli; D. V. Poda; R. B. Podviyanuk; O. G. Polischuk; D. Prosperi; V. N. Shlegel; V. I. Tretyak; I. A. Tupitsyna; Ya. V. Vasiliev; Yu. Ya. Vostretsov

    2010-09-05T23:59:59.000Z

    The radioactive contamination of ZnWO4 crystal scintillators has been measured deep underground at the Gran Sasso National Laboratory (LNGS) of the INFN in Italy with a total exposure 3197 kg x h. Monte Carlo simulation, time-amplitude and pulse-shape analyses of the data have been applied to estimate the radioactive contamination of the ZnWO4 samples. One of the ZnWO4 crystals has also been tested by ultra-low background gamma spectrometry. The radioactive contaminations of the ZnWO4 samples do not exceed 0.002 -- 0.8 mBq/kg (depending on the radionuclide), the total alpha activity is in the range: 0.2 - 2 mBq/kg. Particular radioactivity, beta active 65Zn and alpha active 180W, has been detected. The effect of the re-crystallization on the radiopurity of the ZnWO4 crystal has been studied. The radioactive contamination of samples of the ceramic details of the set-ups used in the crystals growth has been checked by low background gamma spectrometry. A project scheme on further improvement of the radiopurity level of the ZnWO4 crystal scintillators is briefly addressed.

  17. Large single domain 123 material produced by seeding with single crystal rare earth barium copper oxide single crystals

    DOE Patents [OSTI]

    Todt, Volker (Lemont, IL); Miller, Dean J. (Darien, IL); Shi, Donglu (Oak Park, OH); Sengupta, Suvankar (Columbus, OH)

    1998-01-01T23:59:59.000Z

    A method of fabricating bulk YBa.sub.2 Cu.sub.3 O.sub.x where compressed powder oxides and/or carbonates of Y and Ba and Cu present in mole ratios to form YBa.sub.2 Cu.sub.3 O.sub.x are heated in the presence of a Nd.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.y seed crystal to a temperature sufficient to form a liquid phase in the YBa.sub.2 Cu.sub.3 O.sub.x while maintaining the seed crystal solid. The materials are slowly cooled to provide a YBa.sub.2 Cu.sub.3 O.sub.x material having a predetermined number of domains between 1 and 5. Crack-free single domain materials can be formed using either plate shaped seed crystals or cube shaped seed crystals with a pedestal of preferential orientation material.

  18. Correlation functions in liquids and crystals : Free energy functional and liquid - crystal transition

    E-Print Network [OSTI]

    Atul S. Bharadwaj; Swarn L. Singh; Yashwant Singh

    2013-04-03T23:59:59.000Z

    A free energy functional for a crystal that contains both the symmetry conserved and symmetry broken parts of the direct pair correlation function has been used to investigate the crystallization of fluids in three-dimensions. The symmetry broken part of the direct pair correlation function has been calculated using a series in ascending powers of the order parameters and which contains three- and higher-bodies direct correlation functions of the isotropic phase. It is shown that a very accurate description of freezing transitions for a wide class of potentials is found by considering the first two terms of this series. The results found for freezing parameters including structure of the frozen phase for fluids interacting via the inverse power potential u(r) = \\epsilon (\\sigma/r)^{n} for n ranging from 4 to \\infty are in very good agreement with simulation results. It is found that for n > 6.5 the fluid freezes into a face centred cubic (fcc) structure while for n \\leq 6 the body centred cubic (bcc) structure is preferred. The fluid-bcc-fcc triple point is found to be at 1/n = 0.158 which is in good agreement with simulation result.

  19. Crystal chemistry of thorium nitrates and chromates

    SciTech Connect (OSTI)

    Sigmon, Ginger E. [Department of Civil Engineering and Geological Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Burns, Peter C., E-mail: pburns@nd.ed [Department of Civil Engineering and Geological Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States)

    2010-07-15T23:59:59.000Z

    The structures and infrared spectra of six novel thorium compounds are reported. Th(NO{sub 3}){sub 2}(OH){sub 2}(H{sub 2}O){sub 2} (1) crystallizes in space group C2/c, a=14.050(1), b=8.992(7), c=5.954(5) A, {beta}=101.014(2){sup o}. K{sub 2}Th(NO{sub 3}){sub 6} (2), P-3, a=13.606(1), c=6.641(6) A. (C{sub 12}H{sub 28}N){sub 2}Th(NO{sub 3}){sub 6} (3), P2{sub 1}/c, a=14.643(4), b=15.772(5), c=22.316(5) A, {beta}=131.01(1){sup o}. KTh(NO{sub 3}){sub 5}(H{sub 2}O){sub 2} (4), P2{sub 1}/c, a=10.070(8), b=12.731(9), c=13.231(8) A, {beta}=128.647(4){sup o}. Th(CrO{sub 4}){sub 2}(H{sub 2}O){sub 2} (5), P2{sub 1}/n, a=12.731(1), b=9.469(8), c=12.972(1) A, {beta}=91.793(2){sup o}. K{sub 2}Th{sub 3}(CrO{sub 4}){sub 7}(H{sub 2}O){sub 10} (6), Ama2, a=19.302(8), b=15.580(6), c=11.318(6) A. The coordination polyhedra about Th in these structures are diverse. Th is coordinated by 9 O atoms in 5 and 6, seven of which are from monodentate (CrO{sub 4}) tetrahedra and two are (H{sub 2}O). The Th in compound 1 is coordinated by ten O atoms, four of which are O atoms of two bidentate (NO{sub 3}) triangles and six of which are (OH) and (H{sub 2}O). In compounds 2, 3 and 4 the Th is coordinate by 12 O atoms. In 2 and 3 there are six bidentate (NO{sub 3}) triangles, and in 4 ten of the O atoms are part of five bidentate (NO{sub 3}) triangles and the others are (H{sub 2}O) groups. The structural units of these compounds consist of a chain of thorium and nitrate polyhedra (1), isolated thorium hexanitrate clusters (2, 3), an isolated thorium pentanitrate dihydrate cluster (4), and a sheet (6) and framework (5) of thorium and chromate polyhedra. These structures illustrate the complexity inherent in the crystal chemistry of Th. - Graphical Abstract: The structures and infrared spectra of four new Th nitrates and two Th chromates are reported. The coordination numbers of the Th cations range from nine to 12 in these compounds. Structural units consist of isolated clusters, chains, sheets and frameworks.

  20. Polymer Crystallization at NBS/NIST (1960s-1980s) The earliest studies of the crystallization of polymeric materials at NBS/NIST date back to

    E-Print Network [OSTI]

    Polymer Crystallization at NBS/NIST (1960s-1980s) F. Khoury The earliest studies. Mandelkern on the thermodynamics of the bulk crystallization of polymers. The next sustained studies on the crystallization of polymers encompassing extensive structure/property investigations, followed the seminal papers

  1. Origin of platy calcite crystals in hot-spring deposits in the Kenya Rift Valley

    SciTech Connect (OSTI)

    Jones, B. [Univ. of Alberta, Edmonton, Alberta (Canada). Dept. of Earth and Atmospheric Sciences; Renault, R.W. [Univ. of Saskatchewan, Saskatoon, Saskatchewan (Canada). Dept. of Geological Sciences

    1998-09-01T23:59:59.000Z

    Platy calcite crystals, which have their c axis parallel to their shortest length axis, are common components of travertine deposits found around some hot springs in the Kenya Rift Valley. They are composite crystals formed of numerous paper-thin subcrystals. Individual plates allowed to grow without obstruction develop a hexagonal motif. The Kenyan crystals typically form in hot (>75 C) waters that have a low Ca content (<10 mg/l), a high CO{sub 2} content, and a high rate of CO{sub 2} degassing. At Chemurkeu, aggregates of numerous small platy crystals collectively form lattice crystals that superficially resemble ray crystals. The walls of the lattice crystals are formed of large platy crystals that have their long and intermediate length axes aligned parallel to the plane of the long axis of the lattice crystal. Internally, the lattice crystals are formed of small platy calcite crystals arranged in a boxlike pattern that creates the appearance of a lattice when viewed in thin section. Lattice crystals are highly porous, with each pore being enclosed by platy crystals. At Lorusio, travertines are mainly formed of pseudodentrites that are constructed by numerous small platy crystals attached to a main stem which is a large platy crystal that commonly curves along its long axis. The pseudodentrites are the main construction blocks in ledges and lilypads that form in the vent pool and spring outflow channels, where the water is too hot for microbes other than hyperthermophiles. The platy calcite crystals in the Kenyan travertines are morphologically similar to platy calcite crystals that form as scale in pipes in the geothermal fields of New Zealand and hydrothermal angel wing calcite from the La Fe mine in Mexico. Comparison of the Kenyan and New Zealand crystals indicates that platy calcite crystals form from waters with a low Ca{sup 2+} content and a high CO{sub 3}/Ca ratio due to rapid rates of CO{sub 2} degassing.

  2. Skeletal crystals of calcite and trona from hot-spring deposits in Kenya and New Zealand

    SciTech Connect (OSTI)

    Jones, B. [Univ. of Alberta, Edmonton, Alberta (Canada). Dept. of Earth and Atmospheric Sciences; Renaut, R.W. [Univ. of Saskatchewan, Saskatoon, Saskatchewan (Canada). Dept. of Geological Sciences

    1996-01-01T23:59:59.000Z

    Skeletal crystals are hollow crystals that develop because their outer walls grow before their cores. The presence of skeletal crystals of calcite (three types--trigonal prisms, hexagonal prisms, and plates) and trona in hot (> 90 C) spring deposits in New Zealand (Waikite Springs and Ohaaki Pool) and Kenya (Lorusio hot springs) shows that they can form in natural sedimentary regimes. Analysis of samples from these deposits shows that this crystal morphology develops under disequilibrium conditions that are unrelated to a specific environmental or diagenetic setting. Skeletal crystals transform into solid crystals when subsequent precipitation fills their hollow cores. In some cases, this may involve precipitation of crystalline material that has a sieve-like texture. In other examples, the skeletal crystal provides a framework upon which other materials can be precipitated. Walls in the skeletal trigonal calcite prisms from Waikite Springs are formed of subcrystals that mimic the shape of the parent crystal. Similarly, plate-like skeletal crystals from Lorusio are formed of densely packed subcrystals that are < 0.5 {micro}m long. Conversely, the walls of the skeletal hexagonal calcite crystals from Ohaaki Pool and the skeletal trona crystals from Lorusio are not formed of subcrystals. Recognition of skeletal crystals is important because they represent growth that follows the reverse pattern of normal growth. Failure to recognize that crystal growth followed the skeletal motif may lead to false interpretations concerning the growth of a crystal.

  3. Development of Crystal-Tolerant High-Level Waste Glasses

    SciTech Connect (OSTI)

    Matyas, Josef; Vienna, John D.; Schaible, Micah J.; Rodriguez, Carmen P.; Crum, Jarrod V.; Arrigoni, Alyssa L.; Tate, Rachel M.

    2010-12-17T23:59:59.000Z

    Twenty five glasses were formulated. They were batched from HLW AZ-101 simulant or raw chemicals and melted and tested with a series of tests to elucidate the effect of spinel-forming components (Ni, Fe, Cr, Mn, and Zn), Al, and noble metals (Rh2O3 and RuO2) on the accumulation rate of spinel crystals in the glass discharge riser of the high-level waste (HLW) melter. In addition, the processing properties of glasses, such as the viscosity and TL, were measured as a function of temperature and composition. Furthermore, the settling of spinel crystals in transparent low-viscosity fluids was studied at room temperature to access the shape factor and hindered settling coefficient of spinel crystals in the Stokes equation. The experimental results suggest that Ni is the most troublesome component of all the studied spinel-forming components producing settling layers of up to 10.5 mm in just 20 days in Ni-rich glasses if noble metals or a higher concentration of Fe was not introduced in the glass. The layer of this thickness can potentially plug the bottom of the riser, preventing glass from being discharged from the melter. The noble metals, Fe, and Al were the components that significantly slowed down or stopped the accumulation of spinel at the bottom. Particles of Rh2O3 and RuO2, hematite and nepheline, acted as nucleation sites significantly increasing the number of crystals and therefore decreasing the average crystal size. The settling rate of ?10-?m crystal size around the settling velocity of crystals was too low to produce thick layers. The experimental data for the thickness of settled layers in the glasses prepared from AZ-101 simulant were used to build a linear empirical model that can predict crystal accumulation in the riser of the melter as a function of concentration of spinel-forming components in glass. The developed model predicts the thicknesses of accumulated layers quite well, R2 = 0.985, and can be become an efficient tool for the formulation of the crystal-tolerant HLW glasses for higher waste loading. A physical modeling effort revealed that the Stokes and Richardson-Zaki equations can be used to adequately predict the accumulation rate of spinel crystals of different sizes and concentrations in the glass discharge riser of HLW melters. The determined shape factor for the glass beads was only 0.73% lower than the theoretical shape factor for a perfect sphere. The shape factor for the spinel crystals matched the theoretically predicted value to within 10% and was smaller than that of the beads, given the larger drag force caused by the larger surface area-to-volume ratio of the octahedral crystals. In the hindered settling experiments, both the glass bead and spinel suspensions were found to follow the predictions of the Richardson-Zaki equation with the exponent n = 3.6 and 2.9 for glass beads and spinel crystals, respectively.

  4. Getting Crystals Your Crystallographer Will Treasure Richard J. Staples 03/09/2005 1 X-Ray Crystallography Laboratory

    E-Print Network [OSTI]

    Meagher, Mary

    . What information do we get? A crystal structure provides positive identification of a single crystal to be able to perform these analysis. The positive identification of the compound leaves no interpretation material, solvents? What do we grow the crystals in? Other concerns · Crystal Growth · Crystallization

  5. Excitation of intense acoustic waves in hexagonal crystals

    SciTech Connect (OSTI)

    Alshits, V. I., E-mail: alshits@ns.crys.ras.ru; Bessonov, D. A.; Lyubimov, V. N. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)] [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2013-11-15T23:59:59.000Z

    Resonant excitation of an intense elastic wave using reflection of a pump wave from a free surface of hexagonal crystal is described. A resonance arises in the case of specially chosen propagation geometry where the reflecting boundary slightly deviates from symmetric orientation and the propagation direction of an intense reflected wave is close to that of an exceptional bulk wave, which satisfies the free boundary condition in unperturbed symmetric orientation. It is shown that, in crystals with elastic moduli c{sub 44}>c{sub 66}, a resonance arises when the initial boundary is chosen parallel to the hexagonal axis 6, whereas in crystals characterized by the relation c{sub 44}crystals. Examples of crystals are presented in which the beam intensity can be increased by a factor of 5-10 at sufficiently high frequencies, with beam divergence remaining acceptable.

  6. Radiation from polarized electrons in oriented crystals at high energy

    E-Print Network [OSTI]

    V. N. Baier; V. M. Katkov

    2004-05-06T23:59:59.000Z

    Radiation from high energy electrons in an oriented crystal can be considered in a frame of the quasiclassical operator method which appears to be a most satisfactory approach to the problem. Under some quite generic assumptions the general expression is derived for the probability of circularly polarized photon emission from the longitudinally polarized electron in oriented crystal. The particular mechanism of radiation depends on interrelation between the angle of incidence $\\vartheta_0$ (angle between the momentum of initial electron and axis (plane) of crystal) and angle $\\vartheta_v \\equiv V_0/m$ ($V_0$ is the scale of a potential of axis or a plane relative to which the angle $\\vartheta_0$ is defined). When $\\vartheta_0 \\ll \\vartheta_v$ one has magnetic bremsstrahlung type of radiation (with corrections $\\propto \\vartheta_0^2$ which are due to inhomogeneous character of field in crystal). When $\\vartheta_0 \\gg \\vartheta_v$ one obtains the theory of coherent bremsstrahlung, while for $\\vartheta_0 \\geq \\vartheta_v$ one arrives to the modified theory of coherent bremsstrahlung. At high energy radiation in oriented crystals is strongly enhanced comparing with standard bremsstrahlung.

  7. Damage in porous media due to salt crystallization

    E-Print Network [OSTI]

    Noushine Shahidzadeh-Bonn; Julie Desarnaud; François Bertrand; Xavier Chateau; Daniel Bonn

    2010-07-13T23:59:59.000Z

    We investigate the origins of salt damage in sandstones for the two most common salts: sodium chloride and sulfate. The results show that the observed difference in damage between the two salts is directly related to the kinetics of crystallization and the interfacial properties of the salt solutions and crystals with respect to the stone. We show that, for sodium sulfate, the existence of hydrated and anhydrous crystals and specifically their dissolution and crystallization kinetics are responsible for the damage. Using magnetic resonance imaging and optical microscopy we show that when water imbibes sodium sulfate contaminated sandstones, followed by drying at room temperature, large damage occurs in regions where pores are fully filled with salts. After partial dissolution, anhydrous sodium sulfate salt present in these regions gives rise to a very rapid growth of the hydrated phase of sulfate in the form of clusters that form on or close to the remaining anhydrous microcrystals. The rapid growth of these clusters generates stresses in excess of the tensile strength of the stone leading to the damage. Sodium chloride only forms anhydrous crystals that consequently do not cause damage in the experiments.

  8. Radioactive contamination of ZnWO4 crystal scintillators

    E-Print Network [OSTI]

    Belli, P; Cappella, F; Cerulli, R; Danevich, F A; Dubovik, A M; d'Angelo, S; Galashov, E N; Grinyov, B V; Incicchitti, A; Kobychev, V V; Laubenstein, M; Nagornaya, L L; Nozzoli, F; Poda, D V; Podviyanuk, R B; Polischuk, O G; Prosperi, D; Shlegel, V N; Tretyak, V I; Tupitsyna, I A; Vasiliev, Ya V; Vostretsov, Yu Ya

    2010-01-01T23:59:59.000Z

    The radioactive contamination of ZnWO4 crystal scintillators has been measured deep underground at the Gran Sasso National Laboratory (LNGS) of the INFN in Italy with a total exposure 3197 kg x h. Monte Carlo simulation, time-amplitude and pulse-shape analyses of the data have been applied to estimate the radioactive contamination of the ZnWO4 samples. One of the ZnWO4 crystals has also been tested by ultra-low background gamma spectrometry. The radioactive contaminations of the ZnWO4 samples do not exceed 0.002 â?? 0.8 mBq/kg (depending on the radionuclide), the total alpha activity is in the range: 0.2 - 2 mBq/kg. Particular radioactivity, beta active 65Zn and alpha active 180W, has been detected. The effect of the re-crystallization on the radiopurity of the ZnWO4 crystal has been studied. The radioactive contamination of samples of the ceramic details of the set-ups used in the crystals growth has been checked by low background gamma spectrometry. A project scheme on further improvement of the radiopur...

  9. Acoustic transfer of protein crystals from agarose pedestals to micromeshes for high-throughput screening

    SciTech Connect (OSTI)

    Cuttitta, Christina M. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); The City University of New York, 2800 Victory Boulevard, Staten Island, NY 10314 (United States); Ericson, Daniel L. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); University at Buffalo, SUNY, 12 Capen Hall, Buffalo, NY 14260 (United States); Scalia, Alexander [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Binghamton University, 4400 Vestal Parkway East, Binghamton, NY 11973-5000 (United States); Roessler, Christian G. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Teplitsky, Ella [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Stony Brook University, Stony Brook, NY 11794-5215 (United States); Joshi, Karan [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); PEC University of Technology, Chandigarh (India); Campos, Olven [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33414 (United States); Agarwal, Rakhi; Allaire, Marc [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Orville, Allen M. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Sweet, Robert M.; Soares, Alexei S., E-mail: soares@bnl.gov [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States)

    2015-01-01T23:59:59.000Z

    An acoustic high-throughput screening method is described for harvesting protein crystals and combining the protein crystals with chemicals such as a fragment library. Acoustic droplet ejection (ADE) is an emerging technology with broad applications in serial crystallography such as growing, improving and manipulating protein crystals. One application of this technology is to gently transfer crystals onto MiTeGen micromeshes with minimal solvent. Once mounted on a micromesh, each crystal can be combined with different chemicals such as crystal-improving additives or a fragment library. Acoustic crystal mounting is fast (2.33 transfers s{sup ?1}) and all transfers occur in a sealed environment that is in vapor equilibrium with the mother liquor. Here, a system is presented to retain crystals near the ejection point and away from the inaccessible dead volume at the bottom of the well by placing the crystals on a concave agarose pedestal (CAP) with the same chemical composition as the crystal mother liquor. The bowl-shaped CAP is impenetrable to crystals. Consequently, gravity will gently move the crystals into the optimal location for acoustic ejection. It is demonstrated that an agarose pedestal of this type is compatible with most commercially available crystallization conditions and that protein crystals are readily transferred from the agarose pedestal onto micromeshes with no loss in diffraction quality. It is also shown that crystals can be grown directly on CAPs, which avoids the need to transfer the crystals from the hanging drop to a CAP. This technology has been used to combine thermolysin and lysozyme crystals with an assortment of anomalously scattering heavy atoms. The results point towards a fast nanolitre method for crystal mounting and high-throughput screening.

  10. NMR STUDIES OF LIQUID CRYSTALS AND MOLECULES DISSOLVED IN LIQUID CRYSTAL SOLVENTS

    SciTech Connect (OSTI)

    Drobny, G.P.

    1982-11-01T23:59:59.000Z

    This thesis describes several studies in which nuclear magnetic resonance (nmr) spectroscopy has been used to probe the structure, orientation and dynamics of liquid crystal mesogens and molecules dissolved in liquid crystalline phases. In addition, a modern high field nmr spectrometer is described which has been used to perform such nmr studies. Chapter 1 introduces the quantum mechanical formalisms used throughout this thesis and briefly reviews the fundamentals of nuclear spin physics and pulsed nmr spectroscopy. First the density operator is described and a specific form for the canonical ensemble is derived. Then Clebsch-Gordon coefficients, Wigner rotation matrices, and irreducible tensor operators are reviewed. An expression for the equilibrium (Curie) magnetization is obtained and the linear response of a spin system to a strong pulsed r.f. irradiation is described. Finally, the spin interaction Hamiltonians relevant to this work are reviewed together with their truncated forms. Chapter 2 is a deuterium magnetic resonance study of two 'nom' liquid crystals which possess several low temperature mesomorphic phases. Specifically, deuterium quadrupolar echo spectroscopy is used to determine the orientation of the liquid crystal molecules in smectic phases, the changes in molecular orientation and motion that occur at smectic-smectic phase transitions, and the order of the phase transitions. For both compounds, the phase sequence is determined to be isotropic, nematic, smectic A, smectic C, smectic B{sub A}, smectic B{sub C}, and crystalline. The structure of the smectic A phase is found to be consistent with the well-known model of a two dimensional liquid in which molecules are rapidly rotating about their long axes and oriented at right angles to the plane of the layers. Molecules in the smectic C phase are found to have their long axes tilted with respect to the layer normal, and the tilt angle is temperature dependent, increasing from zero at the smectic A - smectic C transition and reaching a maximum at 9{sup o} at the smectic C - smectic B{sub A} transition. This finding contradicts the results of X-ray diffraction studies which indicate that the tilt angle is 18{sup o} and temperature independent. The smectic B{sub A} - smectic B{sub C} phase transition is observed for the first time, and is found to be first order, a result that contradicts the prediction of a mean theory by McMillian. Chapter 3 is a multiple quantum nmr study of n-hexane oriented in a nematic liquid crystal solvent. The basic three pulse multiple quantum experiment is discussed which enables the observation of transitions for which |{Delta}m|>1, and then the technique of the separation of multiple quantum orders by phase incrementation in the multiple quantum evolution period is reviewed (TPPI). An explicit example of multiple quantum nmr is given by the calculation of the multiple quantum spectrum of an oriented methyl group.

  11. Radioactive contamination of BaF2 crystal scintillator

    E-Print Network [OSTI]

    Polischuk, O G; Bernabei, R; Cappella, F; Caracciolo, V; Cerulli, R; Di Marco, A; Danevich, F A; Incicchitti, A; Poda, D V; Tretyak, V I

    2013-01-01T23:59:59.000Z

    Barium fluoride (BaF$_2$) crystal scintillators are promising detectors to search for double beta decay processes in $^{130}$Ba ($Q_{2{\\beta}}$ = 2619(3) keV) and $^{132}$Ba ($Q_{2{\\beta}}$ = 844(1) keV). The $^{130}$Ba isotope is of particular interest because of the indications on 2${\\beta}$ decay found in two geochemical experiments. The radioactive contamination of BaF$_2$ scintillation crystal with mass of 1.714 kg was measured over 113.4 hours in a low-background DAMA/R&D set-up deep underground (3600 m w.e.) at the Gran Sasso National Laboratories of INFN (LNGS, Italy). The half-life of $^{212}$Po (present in the crystal scintillator due to contamination by radium) was estimated as $T_{1/2}$ = 298.8 $\\pm$ 0.8(stat.) $\\pm$ 1.4(syst.) ns by analysis of the events pulse profiles.

  12. Shallow Melt Apparatus for Semicontinuous Czochralski Crystal Growth

    DOE Patents [OSTI]

    Wang, T.; Ciszek, T. F.

    2006-01-10T23:59:59.000Z

    In a single crystal pulling apparatus for providing a Czochralski crystal growth process, the improvement of a shallow melt crucible (20) to eliminate the necessity supplying a large quantity of feed stock materials that had to be preloaded in a deep crucible to grow a large ingot, comprising a gas tight container a crucible with a deepened periphery (25) to prevent snapping of a shallow melt and reduce turbulent melt convection; source supply means for adding source material to the semiconductor melt; a double barrier (23) to minimize heat transfer between the deepened periphery (25) and the shallow melt in the growth compartment; offset holes (24) in the double barrier (23) to increase melt travel length between the deepened periphery (25) and the shallow growth compartment; and the interface heater/heat sink (22) to control the interface shape and crystal growth rate.

  13. Atomic- Resolution Crystal Structure of the Antiviral Lectin Scytovirin

    SciTech Connect (OSTI)

    Moulaei,T.; Botos, I.; Ziolkowska, N.; Bokesch, H.; Krumpe, L.; McKee, T.; O'Keefe, B.; Dauter, Z.; Wlodawer, A.

    2007-01-01T23:59:59.000Z

    The crystal structures of the natural and recombinant antiviral lectin scytovirin (SVN) were solved by single-wavelength anomalous scattering and refined with data extending to 1.3 Angstroms and 1.0 Angstroms resolution, respectively. A molecule of SVN consists of a single chain 95 amino acids long, with an almost perfect sequence repeat that creates two very similar domains (RMS deviation 0.25 Angstroms for 40 pairs of Ca atoms). The crystal structure differs significantly from a previously published NMR structure of the same protein, with the RMS deviations calculated separately for the N- and C-terminal domains of 5.3 Angstroms and 3.7 Angstroms, respectively, and a very different relationship between the two domains. In addition, the disulfide bonding pattern of the crystal structures differs from that described in the previously published mass spectrometry and NMR studies.

  14. Crystal Structure Representations for Machine Learning Models of Formation Energies

    E-Print Network [OSTI]

    Faber, Felix; von Lilienfeld, O Anatole; Armiento, Rickard

    2015-01-01T23:59:59.000Z

    We introduce and evaluate a set of feature vector representations of crystal structures for machine learning (ML) models of formation energies of solids. ML models of atomization energies of organic molecules have been successful using a Coulomb matrix representation of the molecule. We consider three ways to generalize such representations to periodic systems: (i) a matrix where each element is related to the Ewald sum of the electrostatic interaction between two different atoms in the unit cell repeated over the lattice; (ii) an extended Coulomb-like matrix that takes into account a number of neighboring unit cells; and (iii) an Ansatz that mimics the periodicity and the basic features of the elements in the Ewald sum matrix by using a sine function of the crystal coordinates of the atoms. The representations are compared for a Laplacian kernel with Manhattan norm, trained to reproduce formation energies using a data set of 3938 crystal structures obtained from the Materials Project. For training sets consi...

  15. Toward crystal design in organic conductors and superconductors.

    SciTech Connect (OSTI)

    Geiser, U.

    1999-04-23T23:59:59.000Z

    We have seen that many different types of intermolecular interactions in organic conducting cation radical salts. Hydrogen bonding between the donor molecules and the anions is weak but not negligible. The ionic Madelung energy is insufficient to completely intersperse anions and cations, thus the layers favored by the van der Waals interactions remain intact. The search for new conducting and superconducting salts has been mainly by trial-and-error methods, even though simple substitutions have been employed in order to obtain isostructural analogs of successful (e.g., superconducting) salts. However, even seemingly minor substitutions sometimes destroy the packing type, and different crystal structures result. Simulations with the aim at predicting crystal structures have not succeeded, mainly because the different interaction types are of comparable energy, and the delocalized and partial charges render the calculations of the ionic terms extremely unreliable. Clearly, the development of suitable crystal modeling techniques with predictive capabilities is one of the great needs of the field.

  16. Novel variational approach for photonic crystal slab mode calculation

    E-Print Network [OSTI]

    Aram, Mohammad Hasan

    2015-01-01T23:59:59.000Z

    We propose a new method based on variational principle for analysis of photonic crystal (PC) slabs. Most of the methods used today treat PC slab as a three-dimensional (3D) crystal and this makes them very time and/or memory consuming. In this method we use Bloch theorem to expand the field on infinite plane waves which their amplitudes depend on the component perpendicular to the slab surface. By approximating these amplitudes with appropriate functions, we can find modes of PC slabs almost as fast as we can find modes of a two-dimensional (2D) crystal. Besides this advantage, we can also calculate radiation modes with this method which is not feasible with 3D Plane Wave Expansion (PWE) method.

  17. Long DNA molecule as a pseudoscalar liquid crystal

    E-Print Network [OSTI]

    K. G. Petrosyan; Chin-Kun Hu

    2009-05-13T23:59:59.000Z

    We show that a long DNA molecule can form a novel condensed phase of matter, the pseudoscalar liquid crystal, that consists of aperiodically ordered DNA fragments in right-handed B and left-handed Z forms. We discuss the possibility of transformation of B-DNA into Z-DNA and vice versa via first-order phase transitions as well as transformations from the phase with zero total chirality into pure B- or Z-DNA samples through second-order phase transitions. The presented minimalistic phenomenological model describes the pseudoscalar liquid crystal phase of DNA and the phase transition phenomena. We point out to a possibility that a pseudoscalar liquid nano-crystal can be assembled via DNA-programming.

  18. Luminescence from Edge Fracture in Shocked Lithium Fluoride Crystals

    SciTech Connect (OSTI)

    Turley, W. D. [NSTec; Stevens, G. D. [NSTec; Capelle, G. A. [NSTec; Grover, M. [NSTec; Holtkamp, D. B. [LANL; LaLone, B. M. [NSTec; Veeser, L. R. [NSTec, LANL

    2013-04-01T23:59:59.000Z

    Light emitted from a [100] lithium fluoride crystal was characterized under shock wave compression to 28GPa followed by complete stress release at the edges. The light was examined using time-gated optical spectrometry and imaging, time-resolved optical emission measurements, and hydrodynamic modeling. The shock arrival at the circumference of the crystal was delayed relative to the center so that the two regions could be studied at different times. The majority of the light emission originated when the shock waves released at the circumference of the crystal. Unlike previously reported results for shocked lithium fluoride, we found that the light spectrum is not strictly broad band, but has spectral lines associated with atomic lithium in addition to a broad band background. Also, the emission spectrum depends strongly on the gas surrounding the sample. Based on our observations, the line emission appears to be related to fracture of the lithium fluoride crystal from the shock wave releasing at the edges. Experimenters frequently utilize lithium fluoride crystals as transparent windows for observing shock compressed samples. Because of the experimental geometries used, the shock wave in such cases often reaches the circumference of the window at nearly the same moment as when it reaches the center of the sample-window interface. Light generated at the circumference could contaminate the measurement at the interface when this light scatters into the observed region. This background light may be reduced or avoided using experimental geometries which delay the arrival of the shock wave at the edges of the crystal.

  19. Equilibrium configurations of nematic liquid crystals on a torus

    E-Print Network [OSTI]

    Antonio Segatti; Michael Snarski; Marco Veneroni

    2014-06-13T23:59:59.000Z

    The topology and the geometry of a surface play a fundamental role in determining the equilibrium configurations of thin films of liquid crystals. We propose here a theoretical analysis of a recently introduced surface Frank energy, in the case of two-dimensional nematic liquid crystals coating a toroidal particle. Our aim is to show how a different modeling of the effect of extrinsic curvature acts as a selection principle among equilibria of the classical energy, and how new configurations emerge. In particular, our analysis predicts the existence of new stable equilibria with complex windings.

  20. Non-polar Flexoelectrooptic Effect in Blue Phase Liquid Crystals

    E-Print Network [OSTI]

    B. I. Outram; S. J. Elston; F. Castles; M. M. Qasim; H. Coles; H. -Y. Chen; S. -F. Lu

    2014-06-12T23:59:59.000Z

    Blue phase liquid crystals are not usually considered to exhibit a flexoelectrooptic effect, due to the polar nature of flexoelectric switching and the cubic or amorphous structure of blue phases. Here, we derive the form of the flexoelectric contribution to the Kerr constant of blue phases, and experimentally demonstrate and measure the separate contributions to the Kerr constant arising from flexoelectric and dielectric effects. Hence, a non-polar flexoelectrooptic effect is demonstrated in blue phase liquid crystals, which will have consequences for the engineering of novel blue-phase electrooptic technology.

  1. Graphene and chiral nematic liquid crystals: a focus on lasing

    E-Print Network [OSTI]

    Khan, Ammar; Kamarudin, Muhammad Akmal; Kidambi, Piran; Hofmann, Stephan; Wilkinson, Tim; Qasim, Malik

    2015-06-26T23:59:59.000Z

    Graphene and chiral nematic liquid crystals: a focus on lasing Journal: RSC Advances Manuscript ID: RA-ART-05-2015-009415.R1 Article Type: Paper Date Submitted by the Author: 11-Jun-2015 Complete List of Authors: Khan, Ammar... margins Please do not adjust margins Received 00th January 20xx, Accepted 00th January 20xx DOI: 10.1039/x0xx00000x www.rsc.org/ Graphene and chiral nematic liquid crystals: a focus on lasing Ammar A. Khana, Muhammad A. Kamarudina, Piran. R...

  2. Process of making cryogenically cooled high thermal performance crystal optics

    DOE Patents [OSTI]

    Kuzay, T.M.

    1992-06-23T23:59:59.000Z

    A method is disclosed for constructing a cooled optic wherein one or more cavities are milled, drilled or formed using casting or ultrasound laser machining techniques in a single crystal base and filled with porous material having high thermal conductivity at cryogenic temperatures. A non-machined strain-free single crystal can be bonded to the base to produce superior optics. During operation of the cooled optic, N[sub 2] is pumped through the porous material at a sub-cooled cryogenic inlet temperature and with sufficient system pressure to prevent the fluid bulk temperature from reaching saturation. 7 figs.

  3. Process of making cryogenically cooled high thermal performance crystal optics

    DOE Patents [OSTI]

    Kuzay, Tuncer M. (Naperville, IL)

    1992-01-01T23:59:59.000Z

    A method for constructing a cooled optic wherein one or more cavities are milled, drilled or formed using casting or ultrasound laser machining techniques in a single crystal base and filled with porous material having high thermal conductivity at cryogenic temperatures. A non-machined strain-free single crystal can be bonded to the base to produce superior optics. During operation of the cooled optic, N.sub.2 is pumped through the porous material at a sub-cooled cryogenic inlet temperature and with sufficient system pressure to prevent the fluid bulk temperature from reaching saturation.

  4. Visualization of stacking faults in fcc crystals in plastic deformations

    E-Print Network [OSTI]

    Takeshi Kawasaki; Akira Onuki

    2011-11-27T23:59:59.000Z

    Using molecular dynamics simulation, we investigate the dynamics of stacking faults in fcc crystals in uniaxial stretching in a Lennard-Jones binary mixture composed of 4096 particles in three dimensions. We visualize stacking faults using a disorder variable $D_j(t)$ for each particle $j$ constructed from local bond order parameters based on spherical harmonics (Steinhardt order parameters). Also introducing a method of bond breakage, we examine how stacking faults are formed and removed by collective particle motions. These processes are relevant in plasticity of fcc crystals.

  5. Apparatus And Method For Producing Single Crystal Metallic Objects

    DOE Patents [OSTI]

    Huang, Shyh-Chin (Latham, NY); Gigliotti, Jr., Michael Francis X. (Scotia, NY); Rutkowski, Stephen Francis (Duanesburg, NY); Petterson, Roger John (Fultonville, NY); Svec, Paul Steven (Scotia, NY)

    2006-03-14T23:59:59.000Z

    A mold is provided for enabling casting of single crystal metallic articles including a part-defining cavity, a sorter passage positioned vertically beneath and in fluid communication with the part-defining cavity, and a seed cavity positioned vertically beneath and in fluid communication with the sorter passage. The sorter passage includes a shape suitable for encouraging a single crystal structure in solidifying molten metal. Additionally, a portion of the mold between the sorter passage and the part-defining cavity includes a notch for facilitating breakage of a cast article proximate the notch during thermal stress build-up, so as to prevent mold breakage or the inclusion of part defects.

  6. Nonisothermal kinetics of spinel crystallization in a HLW glass

    SciTech Connect (OSTI)

    Casler, D.G.; Hrma, P.

    1999-07-01T23:59:59.000Z

    Nonisothermal kinetics of spinel crystallization in a high-level waste (HLW) glass was predicted using Mehl-Avrami-Johnson-Kolmogorov equation coefficients from isothermal data. The volume fraction of spinel was determined as a function of time, temperature, and cooling rate. The results were verified experimentally. Also predicted was the spatial distribution of spinel in a HLW glass canister. Finally, a parameter study was performed, and an empirical equation was proposed relating the final spinel volume fraction in glass to dimensionless numbers for cooling rate, phase equilibrium, and crystallization kinetics.

  7. Effective dislocation lines in continuously dislocated crystals. III. Kinematics

    E-Print Network [OSTI]

    Andrzej Trzesowski

    2008-07-16T23:59:59.000Z

    A class of congruences of principal Volterra-type effective dislocation lines associated with a dislocation density tensor is distinguished in order to investigate the kinematics of continuized defective crystals in terms of their dislocation densities (tensorial as well as scalar). Moreover, it shown, basing oneself on a formula defining the mean curvature of glide surfaces for principal edge effective dislocation lines, that the considered kinematics of continuized defective crystals is consistent with some relations appearing in the physical theory of plasticity (e.g. with the Orowan-type kinematic relations and with the treatment of shear stresses as driving stresses of moving dislocations).

  8. New Crystal Structures Lift Fog around Protein Folding

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy:Nanowire Solar541,9337, 2011R - 445 CU - 2 3New CrystalNew Crystal

  9. Crystal Structure of a Protein Kinase A Complex

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power Administration would likeConstitution4 Department of WeeklyCrystal Structure of aCrystal

  10. The crystal chemistry of four thorium sulfates

    SciTech Connect (OSTI)

    Albrecht, Amanda J.; Sigmon, Ginger E.; Moore-Shay, Laura; Wei, Rebecca; Dawes, Colleen; Szymanowski, Jennifer [Department of Civil Engineering and Geological Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Burns, Peter C., E-mail: pburns@nd.edu [Department of Civil Engineering and Geological Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States)

    2011-07-15T23:59:59.000Z

    Four thorium sulfate compounds have been synthesized and characterized. [Th(SO{sub 4}){sub 2}(H{sub 2}O){sub 7}].2H{sub 2}O (ThS1) crystallizes in space group P2{sub 1}/m, a=7.2488(4), b=12.1798(7), c=8.0625(5) A, {beta}=98.245(1){sup o}; Na{sub 10}[Th{sub 2}(SO{sub 4}){sub 9}(H{sub 2}O){sub 2}].3H{sub 2}O (ThS2), Pna2{sub 1}, a=17.842(2), b=6.9317(8), c=27.550(3) A; Na{sub 2}[Th{sub 2}(SO{sub 4}){sub 5}(H{sub 2}O){sub 3}].H{sub 2}O (ThS3), C2/c, a=16.639(2), b=9.081(1), c=25.078(3) A, {beta}= 95.322(2){sup o}; [Th{sub 4}(SO{sub 4}){sub 7}(OH){sub 2}(H{sub 2}O){sub 6}].2H{sub 2}O (ThS4), Pnma, a=18.2127(9), b=11.1669(5), c=14.4705(7) A. In all cases the Th cations are coordinated by nine O atoms corresponding to SO{sub 4} tetrahedra, OH groups, and H{sub 2}O groups. The structural unit of ThS1 is an isolated cluster consisting of a single Th polyhedron with two monodentate SO{sub 4} tetrahedra and seven H{sub 2}O groups. A double-wide Th sulfate chain is the basis of ThS2. The structures of ThS3 and ThS4 are frameworks of Th polyhedra and sulfate tetrahedra, and each contains channels that extend through the framework. One of the Th cations in ThS3 is coordinated by a bidentate SO{sub 4} tetrahedron, and ThS4 is unusual in the presence of a pair of Th cations that share a polyhedral face. - Graphical abstract: The structures of four hydrous thorium sulfates are reported that have structural units consisting of finite clusters, chains, and frameworks. Highlights: > Four hydrous thorium sulfates have structural units consisting of finite clusters, chains, and frameworks. > In each the Th cations are coordinated by nine O atoms from SO{sub 4} tetrahedra, OH groups, and H{sub 2}O groups. > The details of the linkages of ThO{sub 9} polyhedra and sulfate tetrahedra vary considerably in these structures.

  11. INVESTIGATING PHARMACEUTICAL CO-CRYSTALS AS A MEANS TO IMPROVE THE SOLUBILITY OF A DRUG

    E-Print Network [OSTI]

    Brown, Rebecca Anderson

    2012-05-31T23:59:59.000Z

    Recently co-crystals have emerged as a potential approach to improve the solubility, dissolution, and bioavailability of active pharmaceutical ingredients (API). Often co-crystal formation is studied in the development stage in order to solve...

  12. Xenocryst assimilation and formation of peritectic crystals during magma contamination: An experimental study

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Xenocryst assimilation and formation of peritectic crystals during magma contamination Minéralogie, Switzerland c Dalhousie University, Department of Earth Sciences, Canada Abstract Contamination and peritectic crystals that form through incongruent melting or dissolution of the original contaminants

  13. Solar energy trapping with modulated silicon nanowire photonic crystals Guillaume Demsy and Sajeev John

    E-Print Network [OSTI]

    John, Sajeev

    Solar energy trapping with modulated silicon nanowire photonic crystals Guillaume Demésy and Sajeev://jap.aip.org/about/rights_and_permissions #12;Solar energy trapping with modulated silicon nanowire photonic crystals Guillaume Demesya

  14. Formation of Spatially Patterned Colloidal Photonic Crystals through the Control of Capillary Forces and

    E-Print Network [OSTI]

    Parikh, Atul N.

    Formation of Spatially Patterned Colloidal Photonic Crystals through the Control of Capillary planar colloidal crystals. These methods rely on controlled gravitational settling or solvent evaporation a concentrated aqueous colloidal sol sand- wiched between a clean, hydrophilic glass and a patterned

  15. Light trapping in thin film solar cells using textured photonic crystal

    DOE Patents [OSTI]

    Yi, Yasha (Somerville, MA); Kimerling, Lionel C. (Concord, MA); Duan, Xiaoman (Amesbury, MA); Zeng, Lirong (Cambridge, MA)

    2009-01-27T23:59:59.000Z

    A solar cell includes a photoactive region that receives light. A photonic crystal is coupled to the photoactive region, wherein the photonic crystal comprises a distributed Bragg reflector (DBR) for trapping the light.

  16. Soluble fullerene derivative in liquid crystal: polymer composites and their impact on photorefractive

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Soluble fullerene derivative in liquid crystal: polymer composites and their impact photorefractive efficiency in polymer­ liquid crystal composites in comparison to previous works on similar) and containing a conducting polymer matrix, such as polymethyl methacrylate (PMMA) doped with N

  17. Crystallization Kinetics and Excess Free Energy of H2O and D2O...

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

    Crystallization Kinetics and Excess Free Energy of H2O and D2O Nanoscale Films of Amorphous Solid Water. Crystallization Kinetics and Excess Free Energy of H2O and D2O Nanoscale...

  18. Predicting material parameters for intrinsic point defect diffusion in Silicon Crystal Growth

    E-Print Network [OSTI]

    Bebendorf, Mario

    by a macroscopic heat transfer model in the entire crystal growth system, taking into account heat conduction [2,3,4]. With such transient heat transfer models the temperature distribution in the crystal can

  19. A process for separation by semi-continuous counter-current crystallization

    E-Print Network [OSTI]

    Aumock, Nathan M. (Nathan Micheal)

    2011-01-01T23:59:59.000Z

    A process is proposed to perform separations via crystallization by using multiple tanks and constraining crystal growth to solid surfaces. Multiple tanks allow multiple recrystallizations to improve product purity and to ...

  20. Optical studies of photonic crystals and high index-contrast microphotonic circuits

    E-Print Network [OSTI]

    Rakich, Peter Thomas

    2006-01-01T23:59:59.000Z

    Both high index-contrast (HIC) photonic crystals and HIC microphotonic circuits are presented in this thesis. Studies of macro-scale 2D photonic crystal meta-materials are first described. Through comparison of experimental ...

  1. Pairing of valence electrons as necessary condition for energy minimization in a crystal

    E-Print Network [OSTI]

    Dolgopolov Stanislav Olegovich

    2014-10-21T23:59:59.000Z

    Pairing of valence electrons can lead to energy minimization of a crystal. It can be proved by use of representation of the valence electrons as plane waves in periodic potential of the crystal.

  2. Photonic crystal surface-emitting lasers enabled by an accidental Dirac point

    DOE Patents [OSTI]

    Chua, Song Liang; Lu, Ling; Soljacic, Marin

    2014-12-02T23:59:59.000Z

    A photonic-crystal surface-emitting laser (PCSEL) includes a gain medium electromagnetically coupled to a photonic crystal whose energy band structure exhibits a Dirac cone of linear dispersion at the center of the photonic crystal's Brillouin zone. This Dirac cone's vertex is called a Dirac point; because it is at the Brillouin zone center, it is called an accidental Dirac point. Tuning the photonic crystal's band structure (e.g., by changing the photonic crystal's dimensions or refractive index) to exhibit an accidental Dirac point increases the photonic crystal's mode spacing by orders of magnitudes and reduces or eliminates the photonic crystal's distributed in-plane feedback. Thus, the photonic crystal can act as a resonator that supports single-mode output from the PCSEL over a larger area than is possible with conventional PCSELs, which have quadratic band edge dispersion. Because output power generally scales with output area, this increase in output area results in higher possible output powers.

  3. Edinburgh Research Explorer Europium-IV: An Incommensurately Modulated Crystal Structure

    E-Print Network [OSTI]

    Millar, Andrew J.

    Edinburgh Research Explorer Europium-IV: An Incommensurately Modulated Crystal Structure 2012, 'Europium-IV: An Incommensurately Modulated Crystal Structure in the Lanthanides' Physical Review to the work immediately and investigate your claim. Download date: 27. Jun. 2014 #12;Europium

  4. Electrolysis at an anthracene crystal/aqueous NO sub 3 sup minus solution interface: The role of crystal defects

    SciTech Connect (OSTI)

    Pope, M.; Mao, B.; Steigman, J.; Geacintov, N.E. (New York Univ., NY (USA))

    1990-03-08T23:59:59.000Z

    The electrolysis of a 1 M solution of NaNO{sub 3} by means of an anthracene crystal electrode results in the production of many surface reaction products, including 9-nitroanthracene (9NA), bianthronyl (BA), and anthraquinone (AQ). The production of 9NA and BA have been shown to depend on the square of the current density. This dependence was rationalized by hypothesizing the need for the simultaneous discharge of two carriers at adjoining lattice defect sites. By annealing the crystals, it was found that the efficiency of producing 9NA was reduced by a factor of as much as 6; this supports the hypothesis.

  5. Optical surface resonance may render photonic crystals ineffective Florencio Garca-Santamara,* Erik C. Nelson, and Paul V. Braun

    E-Print Network [OSTI]

    Braun, Paul

    Optical surface resonance may render photonic crystals ineffective Florencio García crystals and render them ineffective. This surface resonance is dem- onstrated for two different 3D

  6. Role of dye structure in photoinduced reorientation of dye-doped liquid crystals

    E-Print Network [OSTI]

    Marrucci, Lorenzo

    -doped nematic liquid crystals has been measured for a homologous set of dyes belonging to the anthraquinone

  7. Method and apparatus for producing monochromatic radiography with a bent laue crystal

    DOE Patents [OSTI]

    Zhong, Zhong (Apt. I 1131 Chaping 700 E. Loop Rd., Stony Brook, NY 11790); Chapman, Leroy Dean (4 Vermont Cir., Bolingbrook, IL 60440); Thomlinson, William C. (32 E. Masem, East Patchogue, NY 11772)

    2000-03-14T23:59:59.000Z

    A method and apparatus for producing a monochromatic beam. A plurality of beams are generated from a polyenergetic source. The beams are then transmitted through a bent crystal, preferably a bent Laue crystal, having a non-cylindrical shape. A position of the bent crystal is rocked with respect to the polyenergetic source until a plurality of divergent monochromatic beams are emitted from the bent crystal.

  8. Tunable crystals of ultracold polar molecules! Sergey Alyabyshev

    E-Print Network [OSTI]

    Krems, Roman

    Jie Cui Marina Li9nskaya Jesus Perez Rios Ping Xiang Funding: Peter Wall Ins9tute for Advanced + Hcomplicating #12;Quantum Simulation! Design simple controllable systems with some of the same properties as complex quantum systems, such as solid-state crystals! #12;"Cold Controlled Chemistry" PCCP 10, 479 (2008

  9. Crystallization process to reduce NORM-containing waste

    SciTech Connect (OSTI)

    Hayden, C.G. [Inst. of Gas Technology, Chicago, IL (United States); Kraemer, T.F.

    1995-11-01T23:59:59.000Z

    This paper describes a process of Naturally Occurring Radioactive Material (NORM) waste reduction for scales, sludges, and soils. The process involves dissolution and fractional crystallization steps that concentrate the radioactive material into a small mass of barite. The concentration of radium in the product, barite, can be increased or decreased. The NORM-containing barite product is suitable for slurry injection into sandstone formations.

  10. Computation of the scattering properties of nonspherical ice crystals

    E-Print Network [OSTI]

    Zhang, Zhibo

    2004-11-15T23:59:59.000Z

    This thesis is made up of three parts on the computation of scattering properties of nonspherical particles in the atmosphere. In the first part, a new crystal type-droxtal-is introduced to make a better representation of the shape of small ice...

  11. Thermo-optically tunable silicon photonic crystal light modulator

    E-Print Network [OSTI]

    Lee, Jeong-Bong

    Thermo-optically tunable silicon photonic crystal light modulator Yonghao Cui,* Ke Liu, Duncan L (Doc. ID 130726); published October 21, 2010 We designed, fabricated, and characterized a thermo frequency in a silicon-based line defect PhC. The cutoff frequency is shifted because of the thermo

  12. Thermo-optic photonic crystal light modulator Mark T. Tinkera

    E-Print Network [OSTI]

    Lee, Jeong-Bong

    Thermo-optic photonic crystal light modulator Mark T. Tinkera and Jeong-Bong Lee Department be capable of driving substantial changes in the refractive index through the thermo-optic effect. Since the thermo-optic coefficient of silicon is approximately 2.4 10-4 K-1 over this temperature range

  13. Glassy and plastic crystals of cyanoadamantane : a Brillouin scattering investigation

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    L-617 « Glassy » and plastic crystals of cyanoadamantane : a Brillouin scattering investigation J. Abstract. 2014 The elastic constants ofcyanoadamantane have been measured in the plastic and « glassy temperature. The temperature dependence of C11 in the plastic phase has been explain- ed by the setting

  14. Phonon-enhanced crystal growth and lattice healing

    DOE Patents [OSTI]

    Buonassisi, Anthony; Bertoni, Mariana; Newman, Bonna

    2013-05-28T23:59:59.000Z

    A system for modifying dislocation distributions in semiconductor materials is provided. The system includes one or more vibrational sources for producing at least one excitation of vibrational mode having phonon frequencies so as to enhance dislocation motion through a crystal lattice.

  15. Liquid Crystal Optics and Photonics CPHY Assignment 2.

    E-Print Network [OSTI]

    Palffy-Muhoray, Peter

    Liquid Crystal Optics and Photonics CPHY 74495 Assignment 2. P. Pal¤y-Muhoray Jan. 24, 2014 Due: Feb 4, 2014 1. Read pages 25 - 37 of the text (Guenther, Modern Optics). 2. Read Ch 2., Review of Electricity and Magnetism (http://mpal¤y.lci.kent.edu/optics) 3. Red light with wavelength = 632:8nm

  16. Linewidth narrowing and Purcell enhancement in photonic crystal cavities

    E-Print Network [OSTI]

    Vuckovic, Jelena

    . Rev. 69, 681 (1946). 7. O. Painter, R. K. Lee, A. Scherer, A. Yariv, J. D. O'Brien, P.D. Dapkus, and I. References and links 1. L. Pavesi, "A review of the various approaches to a silicon laser," Proc. SPIE 4997. Loncar, T. Yoshie, A. Scherer, P. Gogna, and Y. Qiu, "Low-threshold photonic crystal laser," Appl. Phys

  17. Optical properties of photonic crystal heterostructure cavity lasers

    E-Print Network [OSTI]

    Choquette, Kent

    ; (230.5298) Photonic crystals. References and links 1. O. Painter, R. K. Lee, A. Scherer, A. Yariv, J. D," J. Opt. Soc. Am. B 22, 2581­2595 (2005). 11. F. Bordas, M. J. Steel, C. Seassal, and A. Rahamani

  18. Competition between vitrification and crystallization of methanol at high pressure

    E-Print Network [OSTI]

    Vos, Willem L.

    Competition between vitrification and crystallization of methanol at high pressure Marco J. P methanol at high pressure up to 33 GPa at room temperature with x-ray diffraction, optical polarization and vitrification is observed when methanol is superpressed beyond the freezing pressure of 3.5 GPa: between 5

  19. Antireflection and Enhanced Absorption in Tapered Silicon Photonic Crystals

    E-Print Network [OSTI]

    Coldren, Larry A.

    as applying this structure for solar energy conversion. (a) (b) (c) Figure 1 (a) SEM picture and photograph Optical Society of America OCIS codes: (050.5298) Photonic crystals; (160.4760) Optical properties ; (220 studied as the building blocks to realize functional devices for optical networking, image display, bio

  20. ORIGINAL PAPER Synthesis and Crystal Structure of the Azoxydichinyl Helicene,

    E-Print Network [OSTI]

    Gates, Kent. S.

    by treatment of 6-hydroxylamino- quinoline with xanthine oxidase or treatment of 6-nitroq uinoline with glucose angle of 25.0° between the planes of the two quinoline ring systems. In the crystal, water molecules by Galbraith et al. [9], sug- gesting that 3 was produced in good yield by a different reaction involving

  1. CARIBBEAN SEACRUISE IN LUXURY ABOARD CRYSTAL SERENITY BEST MEDIUM

    E-Print Network [OSTI]

    Spence, Harlan Ernest

    CARIBBEAN SEACRUISE IN LUXURY ABOARD CRYSTAL SERENITY WORLD'S BEST MEDIUM CRUISE LINE SIX and brilliantly colored colonial architecture -- this forms the backdrop for our Cruise the Caribbean Sea program at the Caribbean's many offerings, from picturesque lagoons to quaint towns to bustling beaches. Experience

  2. D-D Nuclear Fusion Using Different Size Pyroelectric Crystals

    E-Print Network [OSTI]

    Danon, Yaron

    D-D Nuclear Fusion Using Different Size Pyroelectric Crystals A. M. Kovanen, D. J. Gillich, T. Z of Homeland Security under cooperative agreement number 2007-DN-077-ER0003. The authors are with the Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY. A. M

  3. Collective phenomena in defect crystals Reimer Kuhn1,

    E-Print Network [OSTI]

    Kühn, Reimer

    by quantum effects. Both thermal and dynamical properties are considered. The influence of interactions Talence cedex, France Received 25 April 2000 We investigate the effects of interactions between substitutional defects on the properties of defect crystals at low temperatures, where defect motion is governed

  4. Photonic Crystal Slot Waveguide Optical Absorption Spectrometer for Highly sensitive

    E-Print Network [OSTI]

    Texas at Austin, University of

    months -Remote Monitoring of BTEX hydrocarbons in water needed -Real-time detection and identification of BTEX hydrocarbons in water needed · Sample collection after-the-fact. -Continuous monitoring of water pollutants in water #12;What is Photonic Crystal? · Periodic electromagnetic media comparable to wavelength

  5. STATISCAL PROCESS CONTROL FOR QUARTZ-CRYSTAL FILTER

    E-Print Network [OSTI]

    Wang, Ji

    .07 #12; SPC spc Abstract The title of the thesis for graduation is statiscal process Process Control (SPC),at the process control we use process flow chart ,cause and effect chart process control (spc) Quartz-crystal filter Control chart Process flow chart Control line #12

  6. Blow up criterion for incompressible nematic liquid crystal flows

    E-Print Network [OSTI]

    Guochun Wu

    2012-10-27T23:59:59.000Z

    In this paper, we consider the short time classical solution to a simplified hydrodynamic flow modeling incompressible, nematic liquid crystal materials in dimension three. We establish a criterion for possible breakdown of such solutions at a finite time. More precisely, if $(u,d)$ is smooth up to time $T$ provided that $\\int_0^T|\

  7. Microfluidic Generation of Lipidic Mesophases for Membrane Protein Crystallization

    E-Print Network [OSTI]

    Kenis, Paul J. A.

    Microfluidic Generation of Lipidic Mesophases for Membrane Protein Crystallization Sarah L. Perry Mathews AVenue, Urbana, Illinois 61801 ReceiVed March 11, 2009 ABSTRACT: We report on a microfluidic conditions of membrane proteins from a membrane-like phase in sub-20 nL volumes. This integrated microfluidic

  8. Radioactive contamination of SrI2(Eu) crystal scintillator

    E-Print Network [OSTI]

    Belli, P; Cerulli, R; Danevich, F A; Galenin, E; Gektin, A; Incicchitti, A; Isaienko, V; Kobychev, V V; Laubenstein, M; Nagorny, S S; Podviyanuk, R B; Tkachenko, S; Tretyak, V I

    2011-01-01T23:59:59.000Z

    A strontium iodide crystal doped by europium (SrI2(Eu)) was produced by using the Stockbarger growth technique. The crystal was subjected to characterisation that included relative photoelectron output and energy resolution for gamma quanta. The intrinsic radioactivity of SrI2(Eu) crystal scintillator was tested both in scintillation mode and by using ultra-low background HPGe gamma spectrometry deep underground. The response of the SrI2(Eu) detector to alpha particles (alpha/beta ratio and pulse shape) was estimated by analysing the 226Ra trace contamination internal to the crystal. We have found alpha/beta=0.55 and no difference in scintillation decay for alpha particles and gamma quanta. The application of the obtained results in the search for the double electron capture and electron capture with positron emission in 84Sr has been investigated at a level of sensitivity T_1/2 \\sim 10^15-10^16 yr. The results of these studies demonstrate the potentiality of this material for a variety of scintillation appli...

  9. Polarization controllable Fresnel lens using dye-doped liquid crystals

    E-Print Network [OSTI]

    Wu, Shin-Tson

    Polarization controllable Fresnel lens using dye- doped liquid crystals Tsung-Hsien Lin,1,2 Yuhua controllable Fresnel zone plate lens is demonstrated using a photo-induced alignment of the dye-doped liquid. X. Ren, S. Liu, and X. Zhang, "Fabrication of off-axis holographic Fresnel lens used as multiplexer

  10. AFM CHARACTERIZATION OF LASER INDUCED DAMAGE ON CDZNTE CRYSTAL SURFACES

    SciTech Connect (OSTI)

    Hawkins, S; Lucile Teague, L; Martine Duff, M; Eliel Villa-Aleman, E

    2008-06-10T23:59:59.000Z

    Semi-conducting CdZnTe (or CZT) crystals can be used in a variety of detector-type applications. CZT shows great promise for use as a gamma radiation spectrometer. However, its performance is adversely affected by point defects, structural and compositional heterogeneities within the crystals, such as twinning, pipes, grain boundaries (polycrystallinity), secondary phases and in some cases, damage caused by external forces. One example is damage that occurs during characterization of the surface by a laser during Raman spectroscopy. Even minimal laser power can cause Te enriched areas on the surface to appear. The Raman spectra resulting from measurements at moderate intensity laser power show large increases in peak intensity that is attributed to Te. Atomic Force Microscopy (AFM) was used to characterize the extent of damage to the CZT crystal surface following exposure to the Raman laser. AFM data reveal localized surface damage in the areas exposed to the Raman laser beam. The degree of surface damage to the crystal is dependent on the laser power, with the most observable damage occurring at high laser power. Moreover, intensity increases in the Te peaks of the Raman spectra are observed even at low laser power with little to no visible damage observed by AFM. AFM results also suggest that exposure to the same amount of laser power yields different amounts of surface damage depending on whether the exposed surface is the Te terminating face or the Cd terminating face of CZT.

  11. A MOLECULAR THEORY OF SURFACE TENSION IN NEMATIC LIQUID CRYSTALS

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1187 A MOLECULAR THEORY OF SURFACE TENSION IN NEMATIC LIQUID CRYSTALS J. D. PARSONS Departamento de 1976, accepte le 10 mai 1976) Résumé. - On calcule la tension superficielle à la surface libre d le plan de la surface; b) il y a un saut de la tension de surface à la transition nématique

  12. Coupling discrete metal nanoparticles to photonic crystal surface resonant modes and

    E-Print Network [OSTI]

    Cunningham, Brian

    Coupling discrete metal nanoparticles to photonic crystal surface resonant modes and application nanoparticles to the resonant mode of a photonic crystal surface has been demonstrated as a means for obtaining of the photonic crystal can couple to plasmon resonances of the metal nanoparticles. Because metal nanoparticles

  13. Low voltage blue-phase liquid crystal displays Linghui Rao,1

    E-Print Network [OSTI]

    Wu, Shin-Tson

    Low voltage blue-phase liquid crystal displays Linghui Rao,1 Zhibing Ge,1 Shin-Tson Wu,1,a of the emerging blue-phase liquid crystal displays BP-LCDs . Simulation results indicate that the generated-effect-induced isotropic-to-anisotropic transition in blue-phase liquid crystal BPLC 1­6 has potential to become next

  14. A Microfluidic Device for Kinetic Optimization of Protein Crystallization and In Situ Structure Determination

    E-Print Network [OSTI]

    Quake, Stephen R.

    A Microfluidic Device for Kinetic Optimization of Protein Crystallization and In Situ Structure Received November 10, 2005; E-mail: quake@stanford.edu Recently microfluidic technologies have emerged microfluidic crystallization devices do not allow the post- crystallization addition of cryoprotectant

  15. Spontaneous emission in GaN/InGaN photonic crystal nanopillars

    E-Print Network [OSTI]

    Boyer, Edmond

    . Sigalas, "InGaN/GaN quantum-well heterostructure light-emitting diodes employing photonic crystal, "III-nitride blue and ultraviolet photonic crystal light emitting diodes," Appl. Phys. Lett. 84, 466, and H. Benisty, "Photonic-crystal GaN light-emitting diodes with tailored guided modes distribution

  16. Novel Cholesteric Glassy Liquid Crystals Comprising Benzene Functionalized with Hybrid Chiral-Nematic Mesogens

    E-Print Network [OSTI]

    Chen, Shaw H.

    of Chemical Engineering, UniVersity of Rochester, Rochester, New York 14623-1212, and Laboratory for Laser reported herein. Films of the 1,3,5-trisubstituted and meta-disubstituted systems show a selective, including liquid crystals, tend to crystallize upon cooling through the melting point, Tm. Crystallization

  17. HANFORD MEDIUM-LOW CURIE WASTE PRETREATMENT ALTERNATIVES PROJECT FRACTIONAL CRYSTALLIZATION PILOT SCALE TESTING FINAL REPORT

    SciTech Connect (OSTI)

    HERTING DL

    2008-09-16T23:59:59.000Z

    The Fractional Crystallization Pilot Plant was designed and constructed to demonstrate that fractional crystallization is a viable way to separate the high-level and low-activity radioactive waste streams from retrieved Hanford single-shell tank saltcake. The focus of this report is to review the design, construction, and testing details of the fractional crystallization pilot plant not previously disseminated.

  18. Influence of Ba content on grain size and dynamics of crystallization in barium ferrite thin films

    E-Print Network [OSTI]

    Laughlin, David E.

    Influence of Ba content on grain size and dynamics of crystallization in barium ferrite thin films of the crystallization process, which ultimately determines the grain size, were studied in barium ferrite thin films. Rapid thermal annealing was used to crystallize the amorphous as-deposited barium ferrite films

  19. Design and fabrication of photonic crystal thin film photovoltaic cells Guillaume Gomarda,b

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Design and fabrication of photonic crystal thin film photovoltaic cells Guillaume Gomarda,b , Ounsi of an absorbing planar photonic crystal within a thin film photovoltaic cell. The devices are based on a stack with large areas. Keywords: Photonic crystal, Photovoltaic solar cell, Thin film solar cell, Hydrogenated

  20. Crystal structures of the free and inhibited forms of plasmepsin I (PMI) from Plasmodium falciparum

    E-Print Network [OSTI]

    Crystal structures of the free and inhibited forms of plasmepsin I (PMI) from Plasmodium falciparum Crystal structure Enzyme inhibition a b s t r a c t Plasmepsin I (PMI) is one of the four vacuolar pepsin antiparasitic agents. We have now solved crystal struc- tures of the recombinant PMI as apoenzyme and in complex

  1. Large pyramid shaped single crystals of BiFeO{sub 3} by solvothermal synthesis method

    SciTech Connect (OSTI)

    Sornadurai, D.; Ravindran, T. R.; Paul, V. Thomas; Sastry, V. Sankara [Condensed Matter Physics Division, Materials Science Group, Physical Metallurgy Division, Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu (India); Condensed Matter Physics Division, Materials Science Group (India)

    2012-06-05T23:59:59.000Z

    Synthesis parameters are optimized in order to grow single crystals of multiferroic BiFeO{sub 3}. 2 to 3 mm size pyramid (tetrahedron) shaped single crystals were successfully obtained by solvothermal method. Scanning electron microscopy with EDAX confirmed the phase formation. Raman scattering spectra of bulk BiFeO3 single crystals have been measured which match well with reported spectra.

  2. Second and Fourth Harmonic Frequencies in Electric Field-Induced Liquid Crystal Reorientations

    E-Print Network [OSTI]

    Wu, Shin-Tson

    Second and Fourth Harmonic Frequencies in Electric Field-Induced Liquid Crystal Reorientations of Central Florida, Orlando, Florida, USA The second and fourth harmonics of low frequency electric field-optical modulation; liquid crystal; second and fourth harmonics 1. INTRODUCTION Nematic liquid crystal (LC) has been

  3. Crystal diffraction lens telescope for focusing nuclear gamma rays

    SciTech Connect (OSTI)

    Smither, R.K.; Fernandez, P.B.; Graber, T. [Argonne National Lab., IL (United States). Advanced Photon Source; Ballmoos, P. von; Naya, J.; Albernhe, F.; Vedrenne, G. [Centre d`Etude Spatiale des Rayonnements, Toulouse (France); Faiz, M. [KFUPM, Dhahran (Saudi Arabia). Physics Dept.

    1996-08-01T23:59:59.000Z

    A crystal diffraction lens was constructed at Argonne National Laboratory for use as a telescope to focus nuclear gamma rays. It consisted of 600 single crystals of germanium arranged in 8 concentric rings. The mounted angle of each crystal was adjusted to intercept and diffract the incoming gamma rays with an accuracy of a few arc sec. The performance of the lens was tested in two ways. In one case, the gamma rays were focused on a single medium size germanium detector. In the second case, the gamma rays were focused on the central germanium detector of a 3 x 3 matrix of small germanium detectors. The efficiency, image concentration and image quality, and shape were measured. The tests performed with the 3 x 3 matrix detector system were particularly interesting. The wanted radiation was concentrated in the central detector. The 8 other detectors were used to detect the Compton scattered radiation, and their energy was summed with coincident events in the central detector. This resulted in a detector with the efficiency of a large detector (all 9 elements) and the background of a small detector (only the central element). The use of the 3 x 3 detector matrix makes it possible to tell if the source is off axis and, if so, to tell in which direction. The crystal lens acts very much like a simple convex lens for visible light. Thus if the source is off to the left then the image will focus off to the right illuminating the detector on the right side: telling one in which direction to point the telescope. Possible applications of this type of crystal lens to balloon and satellite experiments will be discussed.

  4. Synthesis of mesoporous zeolite single crystals with cheap porogens

    SciTech Connect (OSTI)

    Tao Haixiang; Li Changlin; Ren Jiawen [Key Laboratory for Advanced Materials, Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237 (China); Wang Yanqin, E-mail: wangyanqin@ecust.edu.cn [Key Laboratory for Advanced Materials, Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237 (China); Lu Guanzhong, E-mail: gzhlu@ecust.edu.cn [Key Laboratory for Advanced Materials, Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237 (China)

    2011-07-15T23:59:59.000Z

    Mesoporous zeolite (silicalite-1, ZSM-5, TS-1) single crystals have been successfully synthesized by adding soluble starch or sodium carboxymethyl cellulose (CMC) to a conventional zeolite synthesis system. The obtained samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen sorption analysis, {sup 27}Al magic angle spinning nuclear magnetic resonance ({sup 27}Al MAS NMR), temperature-programmed desorption of ammonia (NH{sub 3}-TPD) and ultraviolet-visible spectroscopy (UV-vis). The SEM images clearly show that all zeolite crystals possess the similar morphology with particle size of about 300 nm, the TEM images reveal that irregular intracrystal pores are randomly distributed in the whole crystal. {sup 27}Al MAS NMR spectra indicate that nearly all of the Al atoms are in tetrahedral co-ordination in ZSM-5, UV-vis spectra confirm that nearly all of titanium atoms are incorporated into the framework of TS-1. The catalytic activity of meso-ZSM-5 in acetalization of cyclohexanone and meso-TS-1 in hydroxylation of phenol was also studied. The synthesis method reported in this paper is cost-effective and environmental friendly, can be easily expended to prepare other hierarchical structured zeolites. - Graphical abstract: Mesoporous zeolite single crystals were synthesized by using cheap porogens as template. Highlights: > Mesoporous zeolite (silicalite-1, ZSM-5, TS-1) single crystals were synthesized. > Soluble starch or sodium carboxymethyl cellulose (CMC) was used as porogens. > The mesoporous zeolites had connected mesopores although closed pores existed. > Higher catalytic activities were obtained.

  5. Inclusion property of Cs, Sr, and Ba impurities in LiCl crystal formed by layer-melt crystallization

    SciTech Connect (OSTI)

    Choi, Jung-Hoon; Cho, Yung-Zun; Lee, Tae-Kyo; Eun, Hee-Chul; Kim, Jun-Hong; Park, Hwan-Seo; Kim, In-Tae; Park, Geun-Il [Nuclear Fuel Cycle Waste Treatment Research Division, Korea Atomic Energy Research Institute, Daejeon, 305-353 (Korea, Republic of)

    2013-07-01T23:59:59.000Z

    Pyroprocessing is one of the promising technologies enabling the recycling of spent nuclear fuels from a commercial light water reactor (LWR). In general, pyroprocessing uses dry molten salts as electrolytes. In particular, LiCl waste salt after pyroprocessing contains highly radioactive I/II group fission products mainly composed of Cs, Sr, and Ba impurities. Therefore, it is beneficial to reuse LiCl salt in the pyroprocessing as an electrolyte for economic and environmental issues. Herein, to understand the inclusion property of impurities within LiCl crystal, the physical properties such as lattice parameter change, bulk modulus, and substitution enthalpy of a LiCl crystal having 0-6 at% Cs{sup +} or Ba{sup 2+} impurities under existence of 1 at% Sr{sup 2+} impurity were calculated via the first-principles density functional theory. The substitution enthalpy of LiCl crystals having 1 at% Sr{sup 2+} showed slightly decreased value than those without Sr{sup 2+} impurity. Therefore, through the substitution enthalpy calculation, it is expected that impurities will be incorporated within LiCl crystal as co-existed form rather than as a single component form. (authors)

  6. Synthesis and crystal structure of CuZrTiO{sub 5}-A new crystal structure type

    SciTech Connect (OSTI)

    Troitzsch, Ulrike [Research School of Earth Sciences, Australian National University, Canberra ACT 0200 (Australia); Christy, Andrew G., E-mail: Andrew.Christy@anu.edu.a [Research School of Earth Sciences, Australian National University, Canberra ACT 0200 (Australia); Willis, Anthony C. [Research School of Chemistry, Australian National University, Canberra ACT 0200 (Australia); Ellis, David J. [Research School of Earth Sciences, Australian National University, Canberra ACT 0200 (Australia)

    2010-03-15T23:59:59.000Z

    A new compound, CuZrTiO{sub 5}, was synthesized as strongly pleochroic green crystals from the oxides between 995 and 1010 deg. C, 1 atm. Its crystal structure was determined by single crystal XRD, resulting in R (F{sup 2}>2sigma(F{sup 2}))=0.032 and wR (all data)=0.079). CuZrTiO{sub 5} is orthorhombic, space group P2{sub 1}2{sub 1}2{sub 1}, a=3.5871(3) A, b=6.6968(4) A, c=14.6679(9) A, V=352.35(4) A{sup 3}, Z=4. The structure is topologically similar to In{sub 2}TiO{sub 5} but differs in space group and cation coordination. CuZrTiO{sub 5} has relatively regular TiO{sub 6} polyhedra, but coordination is 7+1 for Zr, and 4+2 for Cu due to the Jahn-Teller effect. Ordering of the long Cu-O bonds causes reduction in symmetry relative to In{sub 2}TiO{sub 5}. Layers of Cu alternate with Ti+Zr on (001), giving rise to a distinct cleavage. Bond valence sums on Ti and Zr are far from ideal, which appears due to the limited ability of this structural topology to avoid close next-nearest neighbour distances. - Graphical abstract: The new compound CuZrTiO{sub 5} is orthorhombic (P2{sub 1}2{sub 1}2{sub 1}), with a=3.5871(3) A, b=6.6968(4) A, c=14.6679(9) A. The structure, determined with single crystal XRD, represents a new crystal structure type that is a slight distortion of that of In{sub 2}TiO{sub 5} but differs in space group and cation coordination.

  7. Crystal structure, growth and characterization of LiPbB?O??: A new congruent melting nonlinear optical crystal

    SciTech Connect (OSTI)

    Xia, M.J.; Li, R.K., E-mail: rkli@mail.ipc.ac.cn

    2013-05-01T23:59:59.000Z

    A new congruent-melting crystal LiPbB?O?? (LPBO) has been grown and its structure was determined by single crystal X-ray diffraction. LPBO crystallizes in a polar space group R3c with a large unit cell of a=b=21.649(11) Å, c=17.193(11) Å, and Z=24. The basic anionic unit, (B?O?)?? group, is connected by terminal O atoms to build an infinite [(B?O?)?]? helical chain along the c axis. Second harmonic generation (SHG) measurements of the title compound indicate that LPBO can be phase matchable and its SHG coefficient is almost equal to that of KDP, which is about 3.3 times that of its analog BaLiB?O??. This significant enhancement of the SHG effect can be tentatively attributed to the lone pair Pb²? cations with severely distorted coordination. LPBO has a wide transparent region from 410 to 2500 nm with a UV absorption edge about 261 nm according to the reflectance spectra. - Graphical abstract: The crystal structure of LiPbB?O?? composed of the (B?O?)?? anionic group and the lone pair Pb and Li polyhedra along c axis. Highlights: • A new congruent-melt NLO crystal LiPbB?O?? (LPBO) has been grown. • The basic structural unit of LPBO is B?O? group same as that found in LiB?O?. • LPBO is phase matchable with SHG signal 10 times that of its Ba-analog. • LPBO is highly transparent within 410–1700 nm with a UV cut-off of 261 nm.

  8. Electromagnetic Wave Propagation in Two-Dimensional Photonic Crystals

    SciTech Connect (OSTI)

    Stavroula Foteinopoulou

    2003-12-12T23:59:59.000Z

    In this dissertation, they have undertaken the challenge to understand the unusual propagation properties of the photonic crystal (PC). The photonic crystal is a medium where the dielectric function is periodically modulated. These types of structures are characterized by bands and gaps. In other words, they are characterized by frequency regions where propagation is prohibited (gaps) and regions where propagation is allowed (bands). In this study they focus on two-dimensional photonic crystals, i.e., structures with periodic dielectric patterns on a plane and translational symmetry in the perpendicular direction. They start by studying a two-dimensional photonic crystal system for frequencies inside the band gap. The inclusion of a line defect introduces allowed states in the otherwise prohibited frequency spectrum. The dependence of the defect resonance state on different parameters such as size of the structure, profile of incoming source, etc., is investigated in detail. For this study, they used two popular computational methods in photonic crystal research, the Finite Difference Time Domain method (FDTD) and the Transfer Matrix Method (TMM). The results for the one-dimensional defect system are analyzed, and the two methods, FDTD and TMM, are compared. Then, they shift their attention only to periodic two-dimensional crystals, concentrate on their band properties, and study their unusual refractive behavior. Anomalous refractive phenomena in photonic crystals included cases where the beam refracts on the ''wrong'' side of the surface normal. The latter phenomenon, is known as negative refraction and was previously observed in materials where the wave vector, the electric field, and the magnetic field form a left-handed set of vectors. These materials are generally called left-handed materials (LHM) or negative index materials (NIM). They investigated the possibility that the photonic crystal behaves as a LHM, and how this behavior relates with the observed negatively refractive phenomena. They found that in the PC system, negative refraction is neither a prerequisite nor guarantees left-handed behavior. They examined carefully the condition to obtain left-handed behavior in the PC. They proposed a wedge type of experiment, in accordance with the experiment performed on the traditional LHM, to test these conditions. They found that for certain frequencies the PC shows left-handed behavior and acts in some respects like a homogeneous medium with a negative refractive index. they used the realistic PC system for this case to show how negative refraction occurs at the interface between a material with a positive and a material with a negative refractive index. Their findings indicate that the formation of the negatively refracted beam is not instantaneous and involves a transient time. With this time-dependent analysis, they were able to address previous controversial issues about negative refraction concerning causality and the speed of light limit. Finally, they attempt a systematic study of anomalous refractive phenomena that can occur at the air-PC interface. They observe cases where only a single refracted beam (in the positive or negative direction) is present, as well as cases with birefringence. they classify these different effects according to their origin and type of propagation (left-handed or not). For a complete study of the system, they also obtain expressions for the energy and group velocities, and show their equality. For cases with very low index contrast, band folding becomes an artificiality. They discuss the validity of their findings when they move to the limit of photonic crystals with a low index modulation.

  9. Acquisition of Single Crystal Growth and Characterization Equipment

    SciTech Connect (OSTI)

    Maple, M. Brian; Zocco, Diego A.

    2008-12-09T23:59:59.000Z

    Final Report for DOE Grant No. DE-FG02-04ER46178 'Acquisition of Single Crystal Growth and Characterization Equipment'. There is growing concern in the condensed matter community that the need for quality crystal growth and materials preparation laboratories is not being met in the United States. It has been suggested that there are too many researchers performing measurements on too few materials. As a result, many user facilities are not being used optimally. The number of proficient crystal growers is too small. In addition, insufficient attention is being paid to the enterprise of finding new and interesting materials, which is the driving force behind much of condensed matter research and, ultimately, technology. While a detailed assessment of this situation is clearly needed, enough evidence of a problem already exists to compel a general consensus that the situation must be addressed promptly. This final report describes the work carried out during the last four years in our group, in which a state-of-the-art single crystal growth and characterization facility was established for the study of novel oxides and intermetallic compounds of rare earth, actinide and transition metal elements. Research emphasis is on the physics of superconducting (SC), magnetic, heavy fermion (HF), non-Fermi liquid (NFL) and other types of strongly correlated electron phenomena in bulk single crystals. Properties of these materials are being studied as a function of concentration of chemical constituents, temperature, pressure, and magnetic field, which provide information about the electronic, lattice, and magnetic excitations at the root of various strongly correlated electron phenomena. Most importantly, the facility makes possible the investigation of material properties that can only be achieved in high quality bulk single crystals, including magnetic and transport phenomena, studies of the effects of disorder, properties in the clean limit, and spectroscopic and scattering studies through efforts with numerous collaborators. These endeavors will assist the effort to explain various outstanding theoretical problems, such as order parameter symmetries and electron-pairing mechanisms in unconventional superconductors, the relationship between superconductivity and magnetic order in certain correlated electron systems, the role of disorder in non-Fermi liquid behavior and unconventional superconductivity, and the nature of interactions between localized and itinerant electrons in these materials. Understanding the mechanisms behind strongly correlated electron behavior has important technological implications.

  10. Crystallization of iysozyme with (R)-, (S)- and (RS)-2-methyl-2,4-pentanediol

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Stauber, Mark; Jakoncic, Jean; Berger, Jacob; Karp, Jerome M.; Axelbaum, Ariel; Sastow, Dahniel; Buldyrev, Sergey V.; Hrnjez, Bruce J.; Asherie, Neer

    2015-03-01T23:59:59.000Z

    Chiral control of crystallization has ample precedent in the small-molecule world, but relatively little is known about the role of chirality in protein crystallization. In this study, lysozyme was crystallized in the presence of the chiral additive 2-methyl-2,4-pentanediol (MPD) separately using the R and S enantiomers as well as with a racemic RS mixture. Crystals grown with (R)-MPD had the most order and produced the highest resolution protein structures. This result is consistent with the observation that in the crystals grown with (R)-MPD and (RS)-MPD the crystal contacts are made by (R)-MPD, demonstrating that there is preferential interaction between lysozymemore »and this enantiomer. These findings suggest that chiral interactions are important in protein crystallization.« less

  11. Kinetic mechanism of chain folding in polymer crystallization

    E-Print Network [OSTI]

    S. Stepanow

    2014-09-22T23:59:59.000Z

    I develop a kinetic mechanism to explain chain folding in polymer crystallization which is based on the competition between the formation of stems, which is due to frequent occupations of trans states along the chains in the supercooled polymer melt, and the random coil structure of the polymer chains. Setting equal the average formation time of stems of length $% d_l$ with the Rouse time of a piece of polymer of the same arc length $d_l$ yields a lower bound for the thickness of stems and bundles. The estimated lamellar thickness is inversely proportional to the supercooling. The present approach emphasizes the importance of repulsive interactions in polymer crystallization, which are expected to be responsible for the logarithmic lamellar thickening and the increase of lamellar thickness with pressure. An expression for the growth rate is derived by considering the growth as a dynamic multistage process.

  12. Dichroism and birefringence of natural violet diamond crystals

    SciTech Connect (OSTI)

    Konstantinova, A. F. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)], E-mail: afkonst@ns.crys.ras.ru; Titkov, S. V. [Russian Academy of Sciences, Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (Russian Federation); Imangazieva, K. B. [Issyk Kul State University (Kyrgyzstan); Evdishchenko, E. A. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Sergeev, A. M. [Karpov Institute of Physical Chemistry, State Scientific Center of the Russian Federation (Russian Federation); Zudin, N. G. [OOO Roni Kerob (Russian Federation); Orekhova, V. P. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2006-05-15T23:59:59.000Z

    Investigation of the optical properties of natural violet diamonds from the Yakutian kimberlites is performed. A red shift of the absorption edge is revealed in the absorption spectra of these crystals. This shift is indicative of the presence of a high concentration of nitrogen in the diamonds studied. Along with the strong band at 0.550 {mu}m, weaker bands at 0.390, 0.456 and 0.496 {mu}m are revealed. It is shown that violet diamond crystals have birefringence and dichroism of about 10{sup -5} and 10{sup -6}, respectively. When a light beam propagates perpendicularly to colored lamellas, the dichroism is much larger and the birefringence is smaller than in the case where the beam direction is parallel to lamellas.

  13. Method to fabricate a tilted logpile photonic crystal

    DOE Patents [OSTI]

    Williams, John D. (Albuquerque, NM); Sweatt, William C. (Albuquerque, NM)

    2010-10-26T23:59:59.000Z

    A method to fabricate a tilted logpile photonic crystal requires only two lithographic exposures and does not require mask repositioning between exposures. The mask and photoresist-coated substrate are spaced a fixed and constant distance apart using a spacer and the stack is clamped together. The stack is then tilted at a crystallographic symmetry angle (e.g., 45 degrees) relative to the X-ray beam and rotated about the surface normal until the mask is aligned with the X-ray beam. The stack is then rotated in plane by a small stitching angle and exposed to the X-ray beam to pattern the first half of the structure. The stack is then rotated by 180.degree. about the normal and a second exposure patterns the remaining half of the structure. The method can use commercially available DXRL scanner technology and LIGA processes to fabricate large-area, high-quality tilted logpile photonic crystals.

  14. Experiment and simulation on one-dimensional plasma photonic crystals

    SciTech Connect (OSTI)

    Zhang, Lin; Ouyang, Ji-Ting, E-mail: jtouyang@bit.edu.cn [School of Physics, Beijing Institute of Technology, Beijing 100081 (China)

    2014-10-15T23:59:59.000Z

    The transmission characteristics of microwaves passing through one-dimensional plasma photonic crystals (PPCs) have been investigated by experiment and simulation. The PPCs were formed by a series of discharge tubes filled with argon at 5?Torr that the plasma density in tubes can be varied by adjusting the discharge current. The transmittance of X-band microwaves through the crystal structure was measured under different discharge currents and geometrical parameters. The finite-different time-domain method was employed to analyze the detailed properties of the microwaves propagation. The results show that there exist bandgaps when the plasma is turned on. The properties of bandgaps depend on the plasma density and the geometrical parameters of the PPCs structure. The PPCs can perform as dynamical band-stop filter to control the transmission of microwaves within a wide frequency range.

  15. Spontaneous Charging and Crystallization of Water Droplets in Oil

    E-Print Network [OSTI]

    Joost de Graaf; Jos Zwanikken; Markus Bier; Arjen Baarsma; Yasha Oloumi; Mischa Spelt; Rene van Roij

    2008-07-31T23:59:59.000Z

    We study the spontaneous charging and the crystallization of spherical micron-sized water-droplets dispersed in oil by numerically solving, within a Poisson-Boltzmann theory in the geometry of a spherical cell, for the density profiles of the cations and anions in the system. We take into account screening, ionic Born self-energy differences between oil and water, and partitioning of ions over the two media. We find that the surface charge density of the droplet as induced by the ion partitioning is significantly affected by the droplet curvature and by the finite density of the droplets. We also find that the salt concentration and the dielectric constant regime in which crystallization of the water droplets is predicted is enhanced substantially compared to results based on the planar oil-water interface, thereby improving quantitative agreement with recent experiments.

  16. Photonic Crystals: Enhancing the Light Output of Scintillation Based Detectors

    E-Print Network [OSTI]

    Knapitsch, Arno Richard

    A scintillator is a material which emits light when excited by ionizing radiation. Such materials are used in a diverse range of applications; From high energy particle physics experiments, X-ray security, to nuclear cameras or positron emission tomography. Future high-energy physics (HEP) experiments as well as next generation medical imaging applications are more and more pushing towards better scintillation characteristics. One of the problems in heavy scintillating materials is related to their high index of refraction. As a consequence, most of the scintillation light produced in the bulk material is trapped inside the crystal due to total internal reflection. The same problem also occurs with light emitting diodes (LEDs) and has for a long time been considered as a limiting factor for their overall efficiency. Recent developments in the area of nanophotonics were showing now that those limitations can be overcome by introducing a photonic crystal (PhC) slab at the outcoupling surface of the substrate. P...

  17. Large mode-volume, large beta, photonic crystal laser resonator

    SciTech Connect (OSTI)

    Dezfouli, Mohsen Kamandar; Dignam, Marc M. [Department of Physics, Engineering Physics and Astronomy, Queen’s University, Kingston, ON K7L 3N6 (Canada)

    2014-12-15T23:59:59.000Z

    We propose an optical resonator formed from the coupling of 13, L2 defects in a triangular-lattice photonic crystal slab. Using a tight-binding formalism, we optimized the coupled-defect cavity design to obtain a resonator with predicted single-mode operation, a mode volume five times that of an L2-cavity mode and a beta factor of 0.39. The results are confirmed using finite-difference time domain simulations. This resonator is very promising for use as a single mode photonic crystal vertical-cavity surface-emitting laser with high saturation output power compared to a laser consisting of one of the single-defect cavities.

  18. Ultrafast dynamics of excitons in tetracene single crystals

    SciTech Connect (OSTI)

    Birech, Zephania; Schwoerer, Heinrich, E-mail: heso@sun.ac.za [Laser Research Institute, Stellenbosch University, Stellenbosch 7600 (South Africa)] [Laser Research Institute, Stellenbosch University, Stellenbosch 7600 (South Africa); Schwoerer, Markus [Department of Physics, University of Bayreuth, Bayreuth (Germany)] [Department of Physics, University of Bayreuth, Bayreuth (Germany); Schmeiler, Teresa; Pflaum, Jens [Experimental Physics VI, University of Würzburg and Bavarian Center for Applied Energy Research, Würzburg (Germany)] [Experimental Physics VI, University of Würzburg and Bavarian Center for Applied Energy Research, Würzburg (Germany)

    2014-03-21T23:59:59.000Z

    Ultrafast exciton dynamics in free standing 200 nm thin tetracene single crystals were studied at room temperature by femtosecond transient absorption spectroscopy in the visible spectral range. The complex spectrally overlapping transient absorption traces of single crystals were systematically deconvoluted. From this, the ultrafast dynamics of the ground, excited, and transition states were identified including singlet exciton fission into two triplet excitons. Fission is generated through both, direct fission of higher singlet states S{sub n} on a sub-picosecond timescale, and thermally activated fission of the singlet exciton S{sub 1} on a 40 ps timescale. The high energy Davydov component of the S{sub 1} exciton is proposed to undergo fission on a sub-picoseconds timescale. At high density of triplet excitons their mutual annihilation (triplet-triplet annihilation) occurs on a <10 ps timescale.

  19. High-Efficiency Nitride-Based Photonic Crystal Light Sources

    Broader source: Energy.gov [DOE]

    The University of California Santa Barbara (UCSB) is maximizing the efficiency of a white LED by enhancing the external quantum efficiency using photonic crystals to extract light that would normally be confined in a conventional structure. Ultimate efficiency can only be achieved by looking at the internal structure of light. To do this, UCSB is focusing on maximizing the light extraction efficiency and total light output from light engines driven by Gallium Nitride (GaN)-based LEDs. The challenge is to engineer large overlap (interaction) between modes and photonic crystals. The project is focused on achieving high extraction efficiency in LEDs, controlled directionality of emitted light, integrated design of vertical device structure, and nanoscale patterning of lateral structure.

  20. Influence of Crystal Expansion/Contraction on Zeolite Membrane Permeation

    SciTech Connect (OSTI)

    Sorenson, Stephanie G [University of Colorado, Boulder; Payzant, E Andrew [ORNL; Noble, Richard D [University of Colorado, Boulder; Falconer, John L. [University of Colorado, Boulder

    2010-01-01T23:59:59.000Z

    X-ray diffraction was used to measure the unit cell parameters of B-ZSM-5, SAPO-34, and NaA zeolite powders as a function of adsorbate loading at 303 K, and in one case, at elevated temperatures. Most adsorbates expanded the zeolite crystals below saturation loading at 303 K: n-hexane and SF6 in B-ZSM-5, methanol and CO2 in SAPO-34, and methanol in NaA zeolite. As the loadings increased, the crystals expanded more. Changes in the unit cell volumes of B-ZSM-5 and SAPO-34 zeolite powders correlated with changes in permeation through zeolite membranes defects. When the zeolite crystals expanded or contracted upon adsorption, the defect sizes decreased or increased. In B-ZSM-5 membranes, the fluxes through defects decreased dramatically when n-hexane or SF6 adsorbed. In contrast, i-butane adsorption at 303 K contracted B-ZSM-5 crystals at low loadings and expanded them at higher loadings. Correspondingly, the flux through B-ZSM-5 membrane defects increased at low i-butane loadings and decreased at high loading because the defects increased in size at low loading and decreased at high loadings. At 398 K and 473 K, n-hexane expanded the B-ZSM-5 unit cell more as the temperature increased from 303 to 473 K. The silicalite-1 and B-ZSM-5 unit cell volumes expanded similarly upon n-hexane adsorption at 303 K; boron substitution had little effect on volume expansion.

  1. Low-frequency electromagnetic field in a Wigner crystal

    SciTech Connect (OSTI)

    Stupka, Anton [Oles Honchar Dnipropetrovs'k National University, Gagarin Ave., 72, 49010 Dnipropetrovs'k (Ukraine)

    2013-03-15T23:59:59.000Z

    Long-wave low-frequency oscillations are described in a Wigner crystal by generalization of the reverse continuum model for the case of electronic lattice. The internal self-consistent long-wave electromagnetic field is used to describe the collective motions in the system. The eigenvectors and eigenvalues of the obtained system of equations are derived. The velocities of longitudinal and transversal sound waves are found.

  2. Design of photonic crystal microcavities for cavity QED

    E-Print Network [OSTI]

    Jelena Vuckovic; Marko Loncar; Hideo Mabuchi; Axel Scherer

    2002-08-15T23:59:59.000Z

    We discuss the optimization of optical microcavity designs based on 2D photonic crystals for the purpose of strong coupling between the cavity field and a single neutral atom trapped within a hole. We present numerical predictions for the quality factors and mode volumes of localized defect modes as a function of geometric parameters, and discuss some experimental challenges related to the coupling of a defect cavity to gas-phase atoms.

  3. Local tuning of photonic crystal cavities using chalcogenide glasses

    E-Print Network [OSTI]

    Andrei Faraon; Dirk Englund; Douglas Bulla; Barry Luther-Davies; Benjamin J. Eggleton; Nick Stoltz; Pierre Petroff; Jelena Vuckovic

    2007-11-09T23:59:59.000Z

    We demonstrate a method to locally change the refractive index in planar optical devices by photodarkening of a thin chalcogenide glass layer deposited on top of the device. The method is used to tune the resonance of GaAs-based photonic crystal cavities by up to 3 nm at 940 nm, with only 5% deterioration in cavity quality factor. The method has broad applications for postproduction tuning of photonic devices.

  4. Local Quantum Dot Tuning on Photonic Crystal Chips

    E-Print Network [OSTI]

    Andrei Faraon; Dirk Englund; Ilya Fushman; Nick Stoltz; Pierre Petroff; Jelena Vuckovic

    2007-03-28T23:59:59.000Z

    Quantum networks based on InGaAs quantum dots embedded in photonic crystal devices rely on QDs being in resonance with each other and with the cavities they are embedded in. We developed a new technique based on temperature tuning to spectrally align different quantum dots located on the same chip. The technique allows for up to 1.8nm reversible on-chip quantum dot tuning.

  5. Incommensurate composite crystal structure of scandium-II

    SciTech Connect (OSTI)

    Fujihisa, Hiroshi; Gotoh, Yoshito; Yamawaki, Hiroshi; Sakashita, Mami; Takeya, Satoshi; Honda, Kazumasa [National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan); Akahama, Yuichi; Kawamura, Haruki [Graduate School of Material Science, University of Hyogo, 3-2-1 Koto, Kamigohri, Hyogo 678-1297 (Japan)

    2005-10-01T23:59:59.000Z

    The long-unknown crystal structure of the high pressure phase scandium-II was solved by powder x-ray diffraction and was found to have tetragonal host channels along the c axis and guest chains that are incommensurate with the host, as well as the high pressure phases of Ba, Sr, Bi, and Sb. The pressure dependences of the lattice constants, the incommensurability, the atomic distances, and the atomic volume were investigated.

  6. Multiply Charged Thorium Crystals for Nuclear Laser Spectroscopy

    SciTech Connect (OSTI)

    Campbell, C. J.; Steele, A. V.; Churchill, L. R.; DePalatis, M. V.; Naylor, D. E.; Kuzmich, A.; Chapman, M. S. [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430 (United States); Matsukevich, D. N. [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430 (United States); Department of Physics and Joint Quantum Institute, University of Maryland, College Park, Maryland 20742 (United States)

    2009-06-12T23:59:59.000Z

    We have produced laser-cooled crystals of {sup 232}Th{sup 3+} in a linear rf Paul trap. This is the first time that a multiply charged ion has been laser cooled. Our work opens an avenue for excitation of the nuclear transition in a trapped, cold {sup 229}Th{sup 3+} ion. Laser excitation of nuclear states would establish a new bridge between atomic and nuclear physics, with the promise of new levels of metrological precision.

  7. Method and apparatus for nucleating the crystallization of undercooled materials

    DOE Patents [OSTI]

    Benson, David K. (Golden, CO); Barret, Peter F. (Peterbourgh, CA)

    1989-01-01T23:59:59.000Z

    A method of storing and controlling a release of latent heat of transition of a phase-change material is disclosed. The method comprises trapping a crystallite of the material between two solid objects and retaining it there under high pressure by applying a force to press the two solid objects tightly together. A crystallite of the material is exposed to a quantity of the material that is in a supercooled condition to nucleate the crystallization of the supercooled material.

  8. Optical Basicity and Nepheline Crystallization in High Alumina Glasses

    SciTech Connect (OSTI)

    Rodriguez, Carmen P.; McCloy, John S.; Schweiger, M. J.; Crum, Jarrod V.; Winschell, Abigail E.

    2011-02-25T23:59:59.000Z

    The purpose of this study was to find compositions that increase waste loading of high-alumina wastes beyond what is currently acceptable while avoiding crystallization of nepheline (NaAlSiO4) on slow cooling. Nepheline crystallization has been shown to have a large impact on the chemical durability of high-level waste glasses. It was hypothesized that there would be some composition regions where high-alumina would not result in nepheline crystal production, compositions not currently allowed by the nepheline discriminator. Optical basicity (OB) and the nepheline discriminator (ND) are two ways of describing a given complex glass composition. This report presents the theoretical and experimental basis for these models. They are being studied together in a quadrant system as metrics to explore nepheline crystallization and chemical durability as a function of waste glass composition. These metrics were calculated for glasses with existing data and also for theoretical glasses to explore nepheline formation in Quadrant IV (passes OB metric but fails ND metric), where glasses are presumed to have good chemical durability. Several of these compositions were chosen, and glasses were made to fill poorly represented regions in Quadrant IV. To evaluate nepheline formation and chemical durability of these glasses, quantitative X-ray diffraction (XRD) analysis and the Product Consistency Test were conducted. A large amount of quantitative XRD data is collected here, both from new glasses and from glasses of previous studies that had not previously performed quantitative XRD on the phase assemblage. Appendix A critically discusses a large dataset to be considered for future quantitative studies on nepheline formation in glass. Appendix B provides a theoretical justification for choice of the oxide coefficients used to compute the OB criterion for nepheline formation.

  9. Origin of electronic transport of lithium phthalocyanine iodine crystal

    SciTech Connect (OSTI)

    Koike, Noritake; Oda, Masato; Shinozuka, Yuzo [Department of Materials Science and Chemistry, Wakayama University, 930 Sakaedani, Wakayama (Japan)

    2013-12-04T23:59:59.000Z

    The electronic structures of Lithium Phthalocyanine Iodine are investigated using density functional theory. Comparing the band structures of several model crystals, the metallic conductivity of highly doped LiPcI{sub x} can be explained by the band of doped iodine. These results reveal that there is a new mechanism for electronic transport of doped organic semiconductors that the dopant band plays the main role.

  10. Growth and properties of Lithium Salicylate single crystals

    SciTech Connect (OSTI)

    Zaitseva, N; Newby, J; Hull, G; Saw, C; Carman, L; Cherepy, N; Payne, S

    2009-02-13T23:59:59.000Z

    An attractive feature of {sup 6}Li containing fluorescence materials that determines their potential application in radiation detection is the capture reaction with slow ({approx}< 100 keV) neutrons: {sup 6}Li + n = {sup 4}He + {sup 3}H + 4.8MeV. The use of {sup 6}Li-salicylate (LiSal, LiC{sub 6}H{sub 5}O{sub 3}) for thermal neutron detection was previously studied in liquid and polycrystalline scintillators. The studies showed that both liquid and polycrystalline LiSal scintillators could be utilized in pulse shape discrimination (PSD) techniques that enable separation of neutrons from the background gamma radiation. However, it was found that the efficiency of neutron detection using LiSal in liquid solutions was severely limited by its low solubility in commonly used organic solvents like, for example, toluene or xylene. Better results were obtained with neutron detectors containing the compound in its crystalline form, such as pressed pellets, or microscopic-scale (7-14 micron) crystals dispersed in various media. The expectation drown from these studies was that further improvement of pulse height, PSD, and efficiency characteristics could be reached with larger and more transparent LiSal crystals, growth of which has not been reported so far. In this paper, we present the first results on growth and characterization of relatively large, a cm-scale size, single crystals of LiSal with good optical quality. The crystals were grown both from aqueous and anhydrous (methanol) media, mainly for neutron detection studies. However, the results on growth and structural characterization may be interesting for other fields where LiSal, together with other alkali metal salicylates, is used for biological, medical, and chemical (as catalyst) applications.

  11. Invariant patterns in crystal lattices: Implications for protein folding algorithms

    SciTech Connect (OSTI)

    Hart, W.E.; Istrail, S.

    1995-12-11T23:59:59.000Z

    Crystal lattices are infinite periodic graphs that occur naturally in a variety of geometries and which are of fundamental importance in polymer science. Discrete models of protein folding use crystal lattices to define the space of protein conformations. Because various crystal lattices provide discretizations of the same physical phenomenon, it is reasonable to expect that there will exist ``invariants`` across lattices that define fundamental properties of protein folding process; an invariant defines a property that transcends particular lattice formulations. This paper identifies two classes of invariants, defined in terms of sublattices that are related to the design of algorithms for the structure prediction problem. The first class of invariants is, used to define a master approximation algorithm for which provable performance guarantees exist. This algorithm can be applied to generalizations of the hydrophobic-hydrophilic model that have lattices other than the cubic lattice, including most of the crystal lattices commonly used in protein folding lattice models. The second class of invariants applies to a related lattice model. Using these invariants, we show that for this model the structure prediction problem is intractable across a variety of three-dimensional lattices. It`` turns out that these two classes of invariants are respectively sublattices of the two- and three-dimensional square lattice. As the square lattices are the standard lattices used in empirical protein folding` studies, our results provide a rigorous confirmation of the ability of these lattices to provide insight into biological phenomenon. Our results are the first in the literature that identify algorithmic paradigms for the protein structure prediction problem which transcend particular lattice formulations.

  12. Tantalum Shear Modulus from Homogenization of Single Crystal Data

    SciTech Connect (OSTI)

    Becker, R

    2007-09-14T23:59:59.000Z

    Elastic constants for tantalum single crystals have been calculated by Orlikowski, et al. [1] for a broad range of temperatures and pressures. These moduli can be utilized directly in continuum crystal simulations or dislocation dynamics calculations where the individual grains of the polycrystalline material are explicitly represented. For simulations on a larger size scale, the volume of material represented by the quadrature points of the simulation codes includes many grains, and average moduli are needed. Analytic bounding and averaging schemes exist, but since these do not account for nonuniform stress and strain within the interacting grains, the upper and lower bounds tend to diverge as the crystal anisotropy increases. Local deformation and stress equilibrium accommodate the anisotropic response of the individual grains. One method of including grain interactions in shear modulus averaging calculations is through a highly-descretized finite element model of a polycrystal volume. This virtual test sample (VTS) can be probed to determine the average response of the polycrystal. The desire to obtain isotropic moduli imposes attributes on the VTS. The grains should be equiax and the crystal orientation distribution function should be random. For these simulations, a cube, 300 {micro}m on a side, was discretized with 1 million finite elements on a regular rectangular mesh. The mesh was seeded with 1000 grains generated using a constrained-random placement algorithm, Figure 1. Since the orientations were simply painted in the mesh, the grain boundaries are irregular. The orientation distribution function is shown as pole figure in Figure 2. It has the appearance of being random. Analysis of the simulation results will be used to determine if the randomness of the texture and number of grains are adequate.

  13. Surface effects in the crystallization process of elastic flexible polymers

    E-Print Network [OSTI]

    Stefan Schnabel; Thomas Vogel; Michael Bachmann; Wolfhard Janke

    2010-02-10T23:59:59.000Z

    Investigating thermodynamic properties of liquid-solid transitions of flexible homopolymers with elastic bonds by means of multicanonical Monte Carlo simulations, we find crystalline conformations that resemble ground-state structures of Lennard-Jones clusters. This allows us to set up a structural classification scheme for finite-length flexible polymers and their freezing mechanism in analogy to atomic cluster formation. Crystals of polymers with "magic length" turn out to be perfectly icosahedral.

  14. Generation of vector beams with liquid crystal disclination lines

    E-Print Network [OSTI]

    Miha ?an?ula; Miha Ravnik; Slobodan Žumer

    2014-08-12T23:59:59.000Z

    We report that guiding light beams, ranging from continuous beams to femtosecond pulses, along liquid crystal defect lines can transform them into vector beams with various polarization profiles. Using Finite Difference Time Domain numerical solving of Maxwell equations, we confirm that the defect in the orientational order of the liquid crystal induces a defect in the light field with twice the winding number of the liquid crystal defect, coupling the topological invariants of both fields. For example, it is possible to transform uniformly-polarized light into light with a radial polarization profile. Our approach also correctly yields a zero-intensity region near the defect core, which is always present in areas of discontinuous light polarization or phase. Using circularly polarized incident light, we show that defects with non-integer winding numbers can be obtained, where topological constants are preserved by phase vortices, demonstrating coupling between the light's spin, orbital angular momentum and polarization profile. Further, we find an ultrafast femtosecond laser pulse travelling along a defect line splits into multiple intensity regions, again depending on the defect's winding number, allowing applications in beam steering and filtering. Finally, our approach describing generation of complex optical fields via coupling with topological defect lines in optically birefringent nematic fluids can be easily extended to high-intensity beams that affect nematic ordering.

  15. Free energy barrier for single-chain melting and crystallization

    E-Print Network [OSTI]

    Wenbing Hu; Daan Frenkel; Vincent B. F. Mathot

    2002-06-28T23:59:59.000Z

    In this paper, we report dynamic Monte Carlo simulations of melting and crystallization in a single-chain system. Their free energy barriers are calculated by the umbrella sampling method and can be described well by a simple expression DeltaF = n Deltaf+sigma (N-n)^(2/3), where n is the amount of molten bonds, Deltaf is the free energy change of each molten bond from a crystalline state, N is the chain length, and sigma is the surface free energy of crystallite. We found that, together with the expression Delta F = n Delta f+ sigma (N-n)^(1/2) for molecular nucleation, the molecular-weight dependent properties of the free-energy barriers for polymer primary and secondary nucleation, in particular, the molecular segregation during crystal growth, can be reproduced. Then for the mechanism of polymer crystallization, we suggested a quantitative model of intramolecular nucleation, as a direct development from the previous qualitative description of molecular nucleation model.

  16. World's Largest Gold Crystal Studied at Los Alamos

    ScienceCinema (OSTI)

    Vogel, Sven; Nakotte, Heinz

    2015-01-07T23:59:59.000Z

    When geologist John Rakovan needed better tools to investigate whether a dazzling 217.78-gram piece of gold was in fact the world's largest single-crystal specimen - a distinguishing factor that would not only drastically increase its market value but also provide a unique research opportunity - he traveled to Los Alamos National Laboratory's Lujan Neutron Scattering Center to peer deep inside the mineral using neutron diffractometry. Neutrons, different from other probes such as X-rays and electrons, are able to penetrate many centimeters deep into most materials. Revealing the inner structure of a crystal without destroying the sample - imperative, as this one is worth an estimated $1.5 million - would allow Rakovan and Lujan Center collaborators Sven Vogel and Heinz Nakotte to prove that this exquisite nugget, which seemed almost too perfect and too big to be real, was a single crystal and hence a creation of nature. Its owner, who lives in the United States, provided the samples to Rakovan to assess the crystallinity of four specimens, all of which had been found decades ago in Venezuela.

  17. Freeze crystallization technology for Kraft black liquor concentration. Third report

    SciTech Connect (OSTI)

    Johnson, W.E.; Rhodes, C.R.

    1985-04-01T23:59:59.000Z

    About 25% of the purchased energy in the pulp and paper industry is used to concentrate black liquor. The technical feasibility of using freeze concentration to supplement evaporation has been successfully demonstrated, and results indicate that energy consumption can be reduced 45%. After compiling a considerable data base on the characteristics of black liquor at low temperature and after developing a computer program to aid analysis, the process chosen was vacuum freezing-vapor absorption (VFVA). A pilot plant was built and operated; however, due to problems with crystallization of the absorbent and contamination, it was found that maintaining the conditions necessary for a continuous process was not practical at the present state of development. Therefore, indirect freezing was used for all subsequent work. This required the design and fabrication of a simple shuttle crystallizer to replace scraped surface units conventionally used. CSI also developed an integrated ice separation column that combined crystal growth, a concentration gradient, and washing all in one unit. Finally, extensive heat transfer coefficient data were collected so that a preliminary design could be completed for a 350 TPD industrial freeze concentration unit. An economic analysis was calculated in order to compare using evaporation and freeze concentration to process the increased liquor flow from a pulp mill expansion. A 200,000 lb/hr freezing unit used to preconcentrate the mill's entire stream up to 18.7% solids would save $10 to $16 per ton of pulp.

  18. Spontaneous parametric down conversion in chirped, aperiodically-poled crystals

    E-Print Network [OSTI]

    X. Sanchez-Lozano; Jose Luis Lucio; Alfred U'Ren

    2014-12-23T23:59:59.000Z

    We present a theoretical analysis of the process of spontaneous parametric down conversion (SPDC) in a non-linear crystal characterized by a linearly-chirped X(2) grating along the direction of propagation. Our analysis leads to an expression for the joint spectral amplitude, based on which we can derive various spectral-temporal properties of the photon pairs and of the heralded single photons obtained from the photon pairs, including: the single photon spectrum, the chronocyclic Wigner function and the Schmidt number. The simulations that we present are for the specific case of a collinear SPDC source based on a PPLN crystal with the signal and idler photons emitted close to the telecom window. We discuss the mechanism for spectral broadening due to the presence of a linearly chirped X(2) grating, showing that not only the width but also to some extent the shape of the SPDC spectrum maybe controlled. Also, we discuss how the fact that the different spectral components are emitted on different planes in the crystal leads to single-photon chirp.

  19. On the Disclination Lines of Nematic Liquid Crystals

    E-Print Network [OSTI]

    Yucheng Hu; Yang Qu; Pingwen Zhang

    2014-08-25T23:59:59.000Z

    Defects in liquid crystals are of great practical importance and theoretical interest. Despite tremendous efforts, predicting the location and transition of defects under various topological constraint and external field remains to be a challenge. We investigate defect patterns of nematic liquid crystals confined in three-dimensional spherical droplet and two-dimensional disk under different boundary conditions, within the Landau-de Gennes model. We implement a spectral method that numerically solves the Landau-de Gennes model with high accuracy, which allows us to study the detailed static structure of defects. We observe five types of defect structures. Among them the 1/2-disclination lines are the most stable structure at low temperature. Inspired by numerical results, we obtain the profile of disclination lines analytically. Moreover, the connection and difference between defect patterns under the Landau-de Gennes model and the Oseen-Frank model are discussed. Finally, four conjectures are made to summarize some important characteristics of defects in the Landau-de Gennes theory. This work is a continuing effort to deepen our understanding on defect patterns in nematic liquid crystals.

  20. Tile and crystal calorimeter for KLOE-2 experiment

    E-Print Network [OSTI]

    F. Happacher; M. Martini; S. Miscetti; I. Sarra

    2009-06-05T23:59:59.000Z

    The upgrade of the DA$\\Phi$NE machine layout requires a modification of the size and position of the inner focusing quadrupoles of KLOE$^2$ thus asking for the realization of two new calorimeters covering the quadrupoles area. To improve the reconstruction of $K_L\\to 2\\pi^0$ events with photons hitting the quadrupoles, a tile calorimeter, QCALT, with high efficiency to low energy photons (20-300 MeV), time resolution of less than 1 ns and space resolution of few cm, is needed. We propose a tile calorimeter with a high granularity readout corresponding to about 2500 silicon photomultipliers (SiPM) of $1\\times 1$ mm$^2$ area. Moreover, the low polar angle regions need the realization of a dense crystal calorimeter with very high time resolution performances to extend the acceptance for multiphotons events. Best candidates for this calorimeter are LYSO crystals with APD readout or PbWO$_4$ crystals with large area SIPM readout.