Sample records for nb ta db

  1. Structural studies of the metal-rich region in the ternary Ta-Nb-S system

    SciTech Connect (OSTI)

    Yao, Xiaoqiang.

    1991-10-07T23:59:59.000Z

    Six new solid solution type compounds have been prepared using high temperature techniques and characterized by means of single crystal x-ray techniques during a study of the metal-rich region of the ternary Ta-Nb-S system. The structures of Nb{sub x}Ta{sub 11-x}S{sub 4} are reminiscent of niobium-rich sulfides, rather than of tantalum-rich sulfides. The coordinations of sulfur are capped trigonal prismatic while the metal coordinations are capped distorted cubic prismatic for Nb{sub x}Ta{sub 11-x}S{sub 4}, and capped distorted cubic prismatic and pentagonal prismatic for Nb{sub 12-x}Ta{sub x}S{sub 4}. The structures of Nb{sub x}Ta{sub 5-x}S{sub 2} contain homoatomic layers sequenced S-M3-M2-M1-M2-M3-S (M is mixed Nb, Ta) generating six-layer sheets, respectively. Weak S-S interactions at 3.26 and 3.19{Angstrom} between sheets contrast with the M-M binding within and between the sheets in these two novel layered compounds. The former are presumably responsible for the observed graphitic slippage of the samples. Nb{sub 21-x}Ta{sub x}S{sub 8} and Nb{sub x}Ta{sub 2-x}S are isostructural with Nb{sub 21}S{sub 8} and Ta{sub 2}S, respectively. Extended Hueckel band calculations were carried out for two layered compounds, Nb{sub x}Ta{sub 5-x}S{sub 2} (x {approx} 1.72) and Nb{sub x}ta{sub 2-x}S (x {approx} 0.95). Based upon band calculations metallic properties can be expected for these two layered compounds. The relative preference of the metal sites for the two metal elements (Ta, Nb) in two layered compounds is explained by the results of the band calculations. 17 figs., 31 tabs., 80 refs.

  2. Microstructure and mechanical properties of Ti-35Nb-6Ta alloy after thermomechanical treatment

    SciTech Connect (OSTI)

    Malek, J., E-mail: jardamalek@seznam.cz [UJP PRAHA a.s., Nad Kaminkou 1345, 156 10 Praha-Zbraslav (Czech Republic); CTU in Prague, Faculty of Mechanical Engineering, Department of Materials Science and Engineering, Karlovo Namesti 13, 121 35 Praha 2 (Czech Republic); Hnilica, F.; Vesely, J. [UJP PRAHA a.s., Nad Kaminkou 1345, 156 10 Praha-Zbraslav (Czech Republic); Smola, B. [Charles University in Prague, Faculty of Mathematics and Physics, Department of Physics of Materials, Ke Karlovu 5, 121 16 Praha 2 (Czech Republic); Bartakova, S.; Vanek, J. [St. Anne's University Hospital Brno, Pekarska 53, 656 91 Brno (Czech Republic)

    2012-04-15T23:59:59.000Z

    The influence of thermo-mechanical treatment on microstructure and mechanical properties of T-35Nb-6Ta has been studied. The thermo-mechanical treatment was chosen to correspond to the production of wire with suitable mechanical properties for dental implants. After casting the alloy was hot forged (700-900 Degree-Sign C), solution treated (850 Degree-Sign C/30 min, water quenched) and cold swaged (reductions up to 91%). The annealing (700 Degree-Sign C/3 h/furnace) or aging (450 Degree-Sign C/8 h/furnace) was used as final heat treatment. The microstructure was studied by using light microscopy, scanning electron microscopy, transmission electron microscopy and XRD analysis. Cold swaging introduces microstructure consisting of highly deformed {beta}-phase grains with dislocation tangles and twins, which ensures high tensile strength about 820 MPa, low Young's modulus ({approx} 50 GPa) and good ductility {approx} 10%. Subsequent aging increases tensile strength (1000 MPa) as well as Young's modulus (75 GPa) without diminishing ductility. Annealing at 700 Degree-Sign C slightly decreases tensile strength (730 MPa) and increases the ductility and Young's modulus (17% and 62 GPa respectively). The mechanical properties attained recommend the thermo-mechanical treatment for production of wires for dental implants. - Highlights: Black-Right-Pointing-Pointer Ti35Nb6Ta alloy prepared via arc melting. Black-Right-Pointing-Pointer Thermo mechanical treatment. Black-Right-Pointing-Pointer Microstructural changes. Black-Right-Pointing-Pointer Mechanical properties.

  3. High Nb, Ta, and Al creep- and oxidation-resistant austenitic stainless steel

    DOE Patents [OSTI]

    Brady, Michael P (Oak Ridge, TN) [Oak Ridge, TN; Santella, Michael L (Knoxville, TN) [Knoxville, TN; Yamamoto, Yukinori (Oak Ridge, TN) [Oak Ridge, TN; Liu, Chain-tsuan (Oak Ridge, TN) [Oak Ridge, TN

    2010-07-13T23:59:59.000Z

    An austenitic stainless steel HTUPS alloy includes, in weight percent: 15 to 30 Ni; 10 to 15 Cr; 2 to 5 Al; 0.6 to 5 total of at least one of Nb and Ta; no more than 0.3 of combined Ti+V; up to 3 Mo; up to 3 Co; up to 1 W; up to 0.5 Cu; up to 4 Mn; up to 1 Si; 0.05 to 0.15 C; up to 0.15 B; up to 0.05 P; up to 1 total of at least one of Y, La, Ce, Hf, and Zr; less than 0.05 N; and base Fe, wherein the weight percent Fe is greater than the weight percent Ni wherein said alloy forms an external continuous scale comprising alumina, nanometer scale sized particles distributed throughout the microstructure, said particles comprising at least one composition selected from the group consisting of NbC and TaC, and a stable essentially single phase fcc austenitic matrix microstructure, said austenitic matrix being essentially delta-ferrite-free and essentially BCC-phase-free.

  4. In situ X-ray diffraction strain-controlled study of Ti–Nb–Zr and Ti–Nb–Ta shape memory alloys: crystal lattice and transformation features

    SciTech Connect (OSTI)

    Dubinskiy, S. [École de technologie supérieure, 1100, Notre-Dame Street West, Montreal, Quebec H3C 1K3 (Canada); National University of Science and Technology “MISIS”, 4, Leninskiy prosp., Moscow 119049 (Russian Federation); Prokoshkin, S. [National University of Science and Technology “MISIS”, 4, Leninskiy prosp., Moscow 119049 (Russian Federation); Brailovski, V., E-mail: vladimir.brailovski@etsmtl.ca [École de technologie supérieure, 1100, Notre-Dame Street West, Montreal, Quebec H3C 1K3 (Canada); Inaekyan, K. [École de technologie supérieure, 1100, Notre-Dame Street West, Montreal, Quebec H3C 1K3 (Canada); Korotitskiy, A. [National University of Science and Technology “MISIS”, 4, Leninskiy prosp., Moscow 119049 (Russian Federation)

    2014-02-15T23:59:59.000Z

    Phase and structure transformations in biomedical Ti–21.8Nb–6.0Zr (TNZ) and Ti–19.7Nb–5.8Ta (TNT) shape memory alloys (at.%) under and without load in the ? 150 to 100 °S temperature range are studied in situ using an original tensile module for a low-temperature chamber of an X-ray diffractometer. Alpha?- and beta-phase lattice parameters, the crystallographic resource of recovery strain, phase and structure transformation sequences, and microstress appearance and disappearance are examined, compared and discussed. For both alloys, the crystallographic resource of recovery strain decreases with temperature increase to become 4.5% for TNZ and 2.5% for TNT alloy (at RT). Loading at low temperatures leads to additional ??-phase formation and reorientation. Heating under load, as compared to strain-free heating, affects the reverse transformation sequence of both alloys in different ways. For TNZ alloy, strain-free heating results in simultaneous ??? and ???? transformations, whereas during heating under stress, they are sequential: ? + ???? precedes ????. For TNT alloy, strain-free heating results in reverse ???? transformation, whereas during heating under stress, ???? transformation is preceded by ??-phase reorientation. - Highlights: • Comparative in situ XRD analysis of Ti–Nb–Zr(Ta) shape memory alloys is realized. • Lattice parameters of ?- and ??-phases are calculated in the ? 150 to + 100 °C range. • The higher the temperature, the lower the ???? transformation strain. • Loading at low temperatures results in ??-phase formation and reorientation. • Transformation sequences upon heating with and without loading are different.

  5. Kinetics of local probe oxidation of ultrathin V, Nb, Ta, Ti, TiN, and W metal films

    SciTech Connect (OSTI)

    Sagunova, I. V., E-mail: pcfme@miee.ru; Shevyakov, V. I.; Gavrilov, S. A.; Belov, A. N. [Moscow Institute of Electronic Technology (Technical University) (Russian Federation)

    2010-12-15T23:59:59.000Z

    The specific features of the kinetics of local probe oxidation of ultrathin V, Nb, Ta, Ti, TiN, and W metal films are studied. It is established that the kinetics of the oxidation process depends on such properties of the material to be oxidized as the resistivity, the presence of a natural surface oxide film and its thickness, the relationship between the densities of the metal and oxide, and the electrochemical constant of the oxidation process. For the material that provides a high efficiency of formation of local insulator nanoregions, vanadium is chosen, since this metal exhibits the maximum rate of anodic probe oxidation.

  6. Characteristics of phase nucleation and growth during oriented crystallization of alloys of the Si-TaSi/sub 2/ and Si-NbSi/sub 2/ eutectic systems

    SciTech Connect (OSTI)

    Grabovetskaya, G.P.; Butkevich, L.M.

    1987-07-01T23:59:59.000Z

    The authors investigate the effect of the nucleation conditions and the initial concentration of the components on the nature of the change in the phase composition and structure along the length of the directionally crystallized bars of alloys in the Si-TaSi/sub 2/ and Si-NbSi/sub 2/ eutectic systems. The compositions of the investigated alloys are given. The starting materials were silicon of semiconductor purity, tantalum, and niobium produced by electron beam melting. The alloys were crystallized directionally by the Czochralski method. The nature of the structure and the volume ratio of the phases in the investigated alloys depend significantly on the type of seed, i.e., on the nucleation conditions of the eutectic grain. The basic phases in the eutectic alloys of the Si-TaSi/sub 2/ and Si-NbSi/sub 2/ systems are the disilicides TaSi/sub 2/ and NbSi/sub 2/ respectively.

  7. PROJECT SUMMARY Many metals, such as the rare earth elements, Nb, Ta, Ge, In, Ga...are finding new applications both

    E-Print Network [OSTI]

    Canet, Léonie

    PROJECT SUMMARY Many metals, such as the rare earth elements, Nb, Ta, Ge, In, Ga...are finding new years ago access to natural metal resources, which were both abundant and easily accessible, caused of geologic context, metal concentration in rocks, separation and concentration techniques, and recycling

  8. 13.21 Geochemistry of the Rare-Earth Element, Nb, Ta, Hf, and Zr Deposits RL Linnen, University of Western Ontario, London, ON, Canada

    E-Print Network [OSTI]

    Chakhmouradian, Anton

    13.21 Geochemistry of the Rare-Earth Element, Nb, Ta, Hf, and Zr Deposits RL Linnen, University of rare metals in natural fluids 551 13.21.2.2.2 Aqueous complexation and mineral solubility 552 13 Acknowledgments 564 References 564 13.21.1 Introduction Rare-element mineral deposits, also called rare-metal

  9. NbF{sub 5} and TaF{sub 5}: Assignment of {sup 19}F NMR resonances and chemical bond analysis from GIPAW calculations

    SciTech Connect (OSTI)

    Biswal, Mamata, E-mail: Mamata.Biswal-Susanta_Kumar_Nayak.Etu@univ-lemans.fr [LUNAM Université, Université du Maine, CNRS UMR 6283, Institut des Molécules et des Matériaux du Mans, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9 (France); Body, Monique, E-mail: monique.body@univ-lemans.fr [LUNAM Université, Université du Maine, CNRS UMR 6283, Institut des Molécules et des Matériaux du Mans, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9 (France); Legein, Christophe, E-mail: christophe.legein@univ-lemans.fr [LUNAM Université, Université du Maine, CNRS UMR 6283, Institut des Molécules et des Matériaux du Mans, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9 (France); Sadoc, Aymeric, E-mail: Aymeric.Sadoc@cnrs-imn.fr [Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, 2 rue de la Houssiničre, BP 32229, 44322 Nantes Cedex 3 (France); Boucher, Florent, E-mail: Florent.Boucher@cnrs-imn.fr [Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, 2 rue de la Houssiničre, BP 32229, 44322 Nantes Cedex 3 (France)

    2013-11-15T23:59:59.000Z

    The {sup 19}F isotropic chemical shifts (?{sub iso}) of two isomorphic compounds, NbF{sub 5} and TaF{sub 5}, which involve six nonequivalent fluorine sites, have been experimentally determined from the reconstruction of 1D {sup 19}F MAS NMR spectra. In parallel, the corresponding {sup 19}F chemical shielding tensors have been calculated using the GIPAW method for both experimental and DFT-optimized structures. Furthermore, the [M{sub 4}F{sub 20}] units of NbF{sub 5} and TaF{sub 5} being held together by van der Waals interactions, the relevance of Grimme corrections to the DFT optimization processes has been evaluated. However, the semi-empirical dispersion correction term introduced by such a method does not show any significant improvement. Nonetheless, a complete and convincing assignment of the {sup 19}F NMR lines of NbF{sub 5} and TaF{sub 5} is obtained, ensured by the linearity between experimental {sup 19}F ?{sub iso} values and calculated {sup 19}F isotropic chemical shielding ?{sub iso} values. The effects of the geometry optimizations have been carefully analyzed, confirming among other matters, the inaccuracy of the experimental structure of NbF{sub 5}. The relationships between the fluorine chemical shifts, the nature of the fluorine atoms (bridging or terminal), the position of the terminal ones (opposite or perpendicular to the bridging ones), the fluorine charges, the ionicity and the length of the M–F bonds have been established. Additionally, for three of the {sup 19}F NMR lines of NbF{sub 5}, distorted multiplets, arising from {sup 1}J-coupling and residual dipolar coupling between the {sup 19}F and {sup 93}Nb nuclei, were simulated yielding to values of {sup 93}Nb–{sup 19}F {sup 1}J-coupling for the corresponding fluorine sites. - Graphical abstract: The complete assignment of the {sup 19}F NMR lines of NbF{sub 5} and TaF{sub 5} allow establishing relationships between the {sup 19}F ?{sub iso} values, the nature of the fluorine atoms (bridging or terminal), the position of the terminal ones (opposite or perpendicular to the bridging ones), the fluorine charges, the ionicity and the length of the M–F bonds. Display Omitted - Highlights: • The {sup 19}F ?{sub iso} values of NbF{sub 5} and TaF{sub 5} have been determined. • The {sup 19}F chemical shielding tensors have been calculated using the GIPAW method. • A confident assignment of the {sup 19}F NMR lines of NbF{sub 5} and TaF{sub 5} is obtained. • The relationships between the {sup 19}F?{sub iso} values and the M–F bonds features are established.

  10. Conduction processes in metal–insulator–metal diodes with Ta{sub 2}O{sub 5} and Nb{sub 2}O{sub 5} insulators deposited by atomic layer deposition

    SciTech Connect (OSTI)

    Alimardani, Nasir; McGlone, John M.; Wager, John F.; Conley, John F., E-mail: jconley@eecs.oregonstate.edu [School of Electrical Engineering and Computer Science, Oregon State University, 1148 Kelley Engineering Center, Corvallis, Oregon 97331-5501 (United States)

    2014-01-15T23:59:59.000Z

    Metal–insulator–metal diodes with Nb{sub 2}O{sub 5} and Ta{sub 2}O{sub 5} insulators deposited via atomic layer deposition are investigated. For both Nb{sub 2}O{sub 5} and Ta{sub 2}O{sub 5}, the dominant conduction process is established as Schottky emission at small biases and Frenkel–Poole emission at large biases. Fowler–Nordheim tunneling is not found to play a role in determining current versus voltage asymmetry. The dynamic dielectric constants are extracted from conduction plots and found to be in agreement with measured optical dielectric constants. Trap energy levels at ?{sub T}???0.62 and 0.53?eV below the conduction band minimum are estimated for Nb{sub 2}O{sub 5} and Ta{sub 2}O{sub 5}, respectively.

  11. Development of Low Cost Membranes (Ta, Nb & Cellulose Acetate) for H{sub 2}/CO{sub 2} Separation in WGS Reactors

    SciTech Connect (OSTI)

    Naidu Seetala; Upali Siriwardane

    2011-06-30T23:59:59.000Z

    The main aim of this work is to synthesize low temperature bimetallic nanocatalysts for Water Gas Shift reaction (WGS) for hydrogen production from CO and steam mixture; and develop low-cost metal (Nb/Ta)/ceramic membranes for H{sub 2} separation and Cellulose Acetate membranes for CO{sub 2} separation. Cu-Ni-Ce/alumina, Fe-Ni-Ce/alumina granular WGS catalysts incorporating metal oxide nanoparticles into alumina support were prepared using sol-gel/oil-drop methods. The catalysts were characterized by Powder X-ray Diffractometer (PXRD), Scanning Electron Microscope (SEM), Differential Thermal Analyzer (DTA), Thermal Gravitational Analyzer (TGA), and Brunauer, Emmett and Teller (BET) techniques. TGA shows sharp weight loss at approximately 215°C and DTA shows dehydration of metal hydroxides between 200°C and 250°C. The PXRD spectra show an increase in crystallinity as a result of heating to 1000°C, and indicating a fine dispersion of the metal oxide nanoparticles in alumina supports during the sol-gel synthesis and calcination at 450°C. BET analysis indicated a mesoporous structure of the granules with high surface area. A gas-phase dynamic flow reactor is used to optimize the reaction temperatures. A gas-phase batch reactor was used to obtain kinetic data and the parameters for maximum CO conversion. In Cu-Ni-Ce/alumina category, Cu(0%)Ni(10%)Ce(11%) was found to be the best WGS catalyst among six Low Temperature Shift (LTS) catalysts with optimum temperatures between 200-300�°C, while Ni(5%)Cu(5%)Ce(11%) was found to be the best among four High Temperature Shift (HTS) catalysts with optimum temperature between 350-400°C. In the Fe-Ni-Ce/alumina category catalysts, Fe(8%)Ni(0%)Ce(8%)/alumina and Fe(6%)Ni(2%)Ce(8%)/alumina catalysts showed optimum WGS reaction temperature below 150°C. All Ni(8-x%)Fe(x%)Ce(8%) had lower WGS reaction efficiencies compared to Ni(8-x%)Cu(x%)Ce(8%). Metal (Nb or Ta)/ceramic membranes for hydrogen separation from the WGS reaction gas products have been prepared using a) sputtering and b) aluminothermic techniques. A polyvinyl-glass permeability tester was used with a gas chromatograph (GC) for H{sub 2}/CO permeability testing. Nb films showed a higher permeability than Ta at a given disk porosity. The aluminothermically deposited membranes have higher H{sub 2} permeability compared to the sputtered films, and Nb-film coated disks showed lower H{sub 2} permeability than Ta-film. A three-stage prototype stainless steel reactor with integrated housing for 1) WGS reaction catalysts, 2) H{sub 2}/CO{sub 2} separation metal/ceramic or metal/asbestos membranes, and 3) CO/CO{sub 2} separation cellulose acetate /filter-paper membranes has been designed and tested to have capabilities to perform WGS reactions at temperatures up to 400°C and withstand gas pressures up to 15 bars. The cracking of ceramic disks and gas leaks were successfully prevented by replacing ceramic disks with asbestos sheets that can easily withstand 400°C. Kinetic studies of H{sub 2} and CO permeabilities were performed through the single and double layer Nb and Ta membranes. Cellulose acetate (CA) films with 25% triethyl citrate (TEC) as plasticizer were prepared for H{sub 2}/CO/CO{sub 2} gas separation with varying thickness of the films by acetone solutions at different concentrations and by dip-coating onto filter papers. The AFM analysis of the CA membrane showed that the uniform coating had fewer and smaller pores as the film thickness increased, and corroborated by gas permeability studies. The CO{sub 2} permeability has decreased faster than CO permeability with the CA/TEC membrane thickness, and findings support that the CA membrane could be used to entrap CO{sub 2}. Several CA/TEC membranes were also staked to increase the separation efficiency. Positron Lifetime Spectroscopy (PLS) was used to estimate the micro-porosity (pore size and concentration) and fractional free volume changes of CA/TEC films, and used to understand the variations observed in the CO{sub 2}/CO permeabilities.

  12. Nickel Alloy, Corrosion and Heat-Resistant, Sheet, Strip, and Plate 72Ni - 15.5Cr - 0.95 (Cb (Nb) + Ta) - 2.5Ti - 0.70Al - 7.0Fe Consumable Electrode, Remelted or Vacuum Induction Melted, Solution Heat Treated, Precipitation-Hardenable

    E-Print Network [OSTI]

    SAE Aerospace Standards. London

    2012-01-01T23:59:59.000Z

    Nickel Alloy, Corrosion and Heat-Resistant, Sheet, Strip, and Plate 72Ni - 15.5Cr - 0.95 (Cb (Nb) + Ta) - 2.5Ti - 0.70Al - 7.0Fe Consumable Electrode, Remelted or Vacuum Induction Melted, Solution Heat Treated, Precipitation-Hardenable

  13. Electrochemical characterization of a low modulus Ti-35.5Nb-7.3Zr-5.7Ta alloy in a simulated body fluid using EIS for biomedical applications

    SciTech Connect (OSTI)

    Bhola, R.; Bhola, S. M.; Mishra, B.; Ayers, R. A.; Olson, D. L. [Department of Metallurgical and Materials Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, CO (United States)

    2011-06-23T23:59:59.000Z

    Electrochemical characterization of the low modulus Ti-35.5Nb-7.3Zr-5.7Ta beta alloy (TNZT) has been performed in phosphate buffer saline solution at 37 deg. C using the non destructive electrochemical impedance spectroscopy technique. Measurements were performed at various immersion intervals at the open circuit potential (OCP), which was also monitored with time. Results obtained for TNZT alloy have been compared with those for the commercially used Ti-6Al-4V mixed alloy (Ti64) and the commercially pure titanium (Ti2) alpha alloy. Potentiodynamic polarization was performed to supplement the data obtained from EIS analysis. The TNZT alloy exhibits a two time constant impedance response, whereas the Ti64 and Ti2 alloys display a one time constant behavior. Human fetal osteoblast cells show a better adhesion and a higher cell count for the TNZT alloy compared to the other two alloys. The present investigation is an effort to understand the correlation between the electrochemical, morphological and cellular characteristics of titanium alloys to qualify them for implant applications.

  14. National Aeronautics and Space Administration TA01 TA02 TA03 TA04

    E-Print Network [OSTI]

    Waliser, Duane E.

    Launch/DropSystems · SpaceTetherAssist · BeamedEnergy/Energy Addition · Nuclear · HighEnergyDensity MaterialsFission · BreakthroughPropulsion SuPPoRting technologieS · PropellantStorage&Transfer TA03 · sPace Power & energy storageNational Aeronautics and Space Administration TA01 TA02 TA03 TA04 TA05 TA06 TA07 TA08 s TA01

  15. Investigation on transition behavior and electrical properties of (K{sub 0.5}Na{sub 0.5}){sub 1-x}Li{sub x}Nb{sub 0.84}Ta{sub 0.1}Sb{sub 0.06}O{sub 3} around polymorphic phase transition region

    SciTech Connect (OSTI)

    Zhu, Chen; Wang, Wenchao; Shi, Honglin; Wang, Fangyu; Cao, Yongge [Department of Physics, Renmin University of China, Beijing 100872, P R China (China) [Department of Physics, Renmin University of China, Beijing 100872, P R China (China); Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Huang, Jiquan; Wang, Chong [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China)] [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Tang, Fei; Yuan, Xuanyi, E-mail: yuanxuanyi@ruc.edu.cn [Department of Physics, Renmin University of China, Beijing 100872, P R China (China)] [Department of Physics, Renmin University of China, Beijing 100872, P R China (China); Liu, Yang [School of Chemistry and Environment Engineering, Shaoguan University, Shaoguan 512005 (China)] [School of Chemistry and Environment Engineering, Shaoguan University, Shaoguan 512005 (China)

    2014-01-15T23:59:59.000Z

    (K{sub 0.5}Na{sub 0.5}){sub 1-x}Li{sub x}Nb{sub 0.84}Ta{sub 0.1}Sb{sub 0.06}O{sub 3} (KNLNTS) lead free ceramics with different Li concentration were fabricated by conventional solid-state reaction method. By increasing Li ions in KNLNTS, the grains grow up and the crystal structure changes from orthorhombic to tetragonal. When 0.03 ? x ? 0.05, the ceramics structure lays in PPT region. Polarization versus electric field (P-E) hysteresis loops at room temperature show good ferroelectric properties and the remnant polarization decreases by increasing Li content while coercive electric keeps almost unchanged. In PPT region, taking x = 0.04 as an example, the sample shows excellent dielectric properties: the dielectric constant is 1159 and loss tangent is 0.04, while the piezoelectric constant d{sub 33} is 245 pC/N and kp is 0.44 at room temperature, it is promising for (K{sub 0.5}Na{sub 0.5}){sub 1-x}Li{sub x}Nb{sub 0.84}Ta{sub 0.1}Sb{sub 0.06}O{sub 3} with 4 at. % Li to substitute PZT.

  16. Performance Boundaries in Nb3Sn Superconductors

    E-Print Network [OSTI]

    Godeke, Arno

    2006-01-01T23:59:59.000Z

    Boundaries in Nb 3 Sn Superconductors – Berkeley, CABoundaries in Nb 3 Sn Superconductors – Berkeley, CABoundaries in Nb 3 Sn Superconductors Arno Godeke Berkeley,

  17. TA-55 change control manual

    SciTech Connect (OSTI)

    Blum, T.W.; Selvage, R.D.; Courtney, K.H.

    1997-11-01T23:59:59.000Z

    This manual is the guide for initiating change at the Plutonium Facility, which handles the processing of plutonium as well as research on plutonium metallurgy. It describes the change and work control processes employed at TA-55 to ensure that all proposed changes are properly identified, reviewed, approved, implemented, tested, and documented so that operations are maintained within the approved safety envelope. All Laboratory groups, their contractors, and subcontractors doing work at TA-55 follow requirements set forth herein. This manual applies to all new and modified processes and experiments inside the TA-55 Plutonium Facility; general plant project (GPP) and line item funded construction projects at TA-55; temporary and permanent changes that directly or indirectly affect structures, systems, or components (SSCs) as described in the safety analysis, including Facility Control System (FCS) software; and major modifications to procedures. This manual does not apply to maintenance performed on process equipment or facility SSCs or the replacement of SSCs or equipment with documented approved equivalents.

  18. Fabrication of fine-grain tantalum diffusion barrier tube for Nb{sub 3}Sn conductors

    SciTech Connect (OSTI)

    Hartwig, K. T.; Balachandran, S.; Mezyenski, R.; Seymour, N. [Department of Mechanical Engineering, Texas A and M University, TX 77843 (United States); Robinson, J.; Barber, R. E. [Shear Form Inc, 207 Dellwood St, Bryan 77801 (United States)

    2014-01-27T23:59:59.000Z

    Diffusion barriers used in Nb{sub 3}Sn wire are often fabricated by wrapping Ta sheet into a tube with an overlap seam. A common result of such practice is non-uniform deformation in the Ta sheet as it thins by wire drawing because of non-uniform grain size and texture in the original Ta sheet. Seamless Ta tube with a fine-grain and uniform microstructure would be much better for the diffusion barrier application, but such material is expensive and difficult to manufacture. This report presents results on a new fabrication strategy for Ta tube that shows promise for manufacture of less costly tube with an improved microstructure. The fabrication method begins with seam-welded tube but gives a fine-grain uniform microstructure with little difference between the longitudinal seam weld region and the parent metal after post-weld processing. Severe plastic deformation processing (SPD) applied by area reduction extrusion and tube equal channel angular extrusion (tECAE) are used to refine and homogenize the microstructure. Microstructure and mechanical property results are presented for Ta tubes fabricated by this new processing strategy.

  19. Structure and physical properties of EuTa{sub 2}O{sub 6} tungsten bronze polymorph

    SciTech Connect (OSTI)

    Kolodiazhnyi, T., E-mail: kolodiazhnyi.taras@nims.go.jp; Sakurai, H.; Vasylkiv, O.; Borodianska, H. [National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan); Forbes, S.; Mozharivskyj, Y. [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4M1 (Canada)

    2014-08-11T23:59:59.000Z

    A tetragonal tungsten bronze (TTB) polymorph of EuTa{sub 2}O{sub 6} was prepared and analyzed. EuTa{sub 2}O{sub 6} crystallizes in the centrosymmetric Pnam space group (with unit cell: a?=?12.3693, b?=?12.4254, and c?=?7.7228?Ĺ) isomorphous with orthorhombic ?-SrTa{sub 2}O{sub 6}. In contrast to early reports, we see no evidence of deviation from paramagnetic Curie-Weiss behavior among the Eu{sup 2+} 4f{sup 7}spins in EuTa{sub 2}O{sub 6} down to 2?K. Dielectric constant shows a broad peak at ca. 50?K with dielectric dispersion resembling diffuse phase transition. The relaxation time, however, follows a simple (non-freezing) thermally activated process with an activation energy of 92?meV and an attempt frequency of f{sub 0}?=?5.79?×?10{sup 12?}Hz. A thermal conductivity of EuTa{sub 2}O{sub 6} shows a low-temperature (T???30?K) “plateau” region reminiscent of a glass-like behaviour in Nb-based TTB compounds. This behaviour can be attributed to the loosely bound Eu{sup 2+} ions occupying large tricapped trigonal prismatic sites in the EuTa{sub 2}O{sub 6} structure.

  20. Memo - Legacy Technical Area (TA)-55 Nitrate Salt Wastes at TA...

    Office of Environmental Management (EM)

    Memo - Legacy Technical Area (TA)-55 Nitrate Salt Wastes at TA-54, Potential Applicability of Resource Conservation and Recovery Act (RCRA) D001D002D003 Waste Codes Memo - Legacy...

  1. Characterization of Rh films on Ta(110)

    SciTech Connect (OSTI)

    Jiang, L.Q.; Ruckman, M.W.; Strongin, M.

    1989-01-01T23:59:59.000Z

    The surface and electronic structure of Rh films on Ta(110) up to several monolayers thick on Ta(110) are characterized by photoemission, Auger emission, low energy electron diffraction and low energy ion scattering. From the variation of the Rh Auger peak-to-peak intensity as a function of evaporation time, Rh/Ta(110) appears to grow in the Stranski-Krastanov mode at room temperature. However, the LEIS data show that the Rh adatoms begin to cluster on Ta(110) before growth of the monolayer is completed. Diffuse LEED scattering suggests that the Rh films are disordered. Photoemission shows that Rh chemisorption on Ta(110) generates two peaks located at 1.2 and 2. 5 eV binding energy during the initial phase of thin film growth (0 < {Theta} < 0.5 ML). By 0.75 ML Rh coverage, those states merge into a broad structure centered near 2 eV binding energy. Photoemission peaks typical of a Rh(111) surface are seen at higher coverages ({Theta} > 3.7 ML). Photoemission data for CO covered surfaces show that CO dissociates on the Rh/Ta(110) surface for Rh coverages less than 2.5 ML and also show that the Rh clusters develop at least one site capable of molecular CO adsorption above 0.3 ML Rh coverage. 38 refs., 5 figs.

  2. SciDB for Array Data

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

    SciDB SciDB Screen Shot 2014 03 15 at 12.06.05 AM Bird's Eye View - SciDB Testbed at NERSC Pioneers High Usability Big Data Analytic Infrastructure. Motivation? It's painful to...

  3. 2014/2015 TA Training Program Page 1 of 4 Call for Proposals for 2014/2015 TA Training Programs

    E-Print Network [OSTI]

    Handy, Todd C.

    2014/2015 TA Training Program Page 1 of 4 Call for Proposals for 2014/2015 TA Training Programs, the University is committed to providing educational programs specifically addressing TAs needs. The TA Training for the development, delivery, and assessment of TA training programs. In so doing, we expect a significant increase

  4. ORIGINAL PAPER NbTa fractionation by partial melting at the titaniterutile

    E-Print Network [OSTI]

    , Chinese Academy of Sciences, PO Box 9825, Beijing 100029, China 123 Contrib Mineral Petrol (2011) 161

  5. Effect of proton exchange on the nonlinear optical properties of LiNb& Wei-Yung Hsu,~) Craig S. Willand, Venkatraman Gopalan,a) and Moo1 C. Gupta

    E-Print Network [OSTI]

    Gopalan, Venkatraman

    Effect of proton exchange on the nonlinear optical properties of LiNb& and LiTaO, Wei-Yung Hsu 1992) The effect of proton exchange carried out using benzoic and pyrophosphoric acid on the nonlinear of proton exchange with either benzoic or pyrophosphoric acid under the conditions studied. Some recovery

  6. e[doxe ta'i aJlivai kaqa; kai; ta'i boula'i-ejpeidh; oiJ Erbitai'oi o{ka to; provteron ta;m

    E-Print Network [OSTI]

    Abbondandolo, Alberto

    e[doxe ta'i aJlivai kaqa; kai; ta'i boula'i- ejpeidh; oiJ Ă?Erbitai'oi o{ka to; provteron taJma'i ta;" creiva" parischmevnwn. e[doxe ta'i aJlivai kaqa; kai; ta'i boula'i- ejpeidh; oiJ Ă?Erbitai'oi o'i povlei ta'i aJma'i ta;" creiva" parischmevnwn. e[doxe ta'i aJlivai kaqa; kai; ta'i boula'i- ejpeidh; oi

  7. Unexpected formation of a trinuclear complex containing a Ta(IV)-Ta(IV) bond in the reactions of ButN=Ta(NMe2)3 with silanes

    SciTech Connect (OSTI)

    Cheng, Shu-Jian [University of Tennessee, Knoxville (UTK); Dougan, Brenda A. [University of Tennessee, Knoxville (UTK); Steren, Carlos A. [University of Tennessee, Knoxville (UTK); Wang, Xiaoping [ORNL; Chen, Xue-Tai [University of Tennessee, Knoxville (UTK); Lin, Zhenyang [University of Tennessee, Knoxville (UTK); Xue, Zi-Ling [University of Tennessee, Knoxville (UTK)

    2011-01-01T23:59:59.000Z

    A new trinuclear species containing a Ta(IV)-Ta(IV) bond, Ta{sub 3}({mu}-H)({mu}-NMe{sub 2})({mu}NBu{sup t}){sub 2}(NBu{sup t})(NMe{sub 2}){sub 5}, has been formed by reductive elimination of H{sub 2}. Ta{sub 2}H{sub 2}({mu}-NMe{sub 2}){sub 2}(NMe{sub 2}){sub 2}(NBu{sup t}){sub 2} has also been isolated. O{sub 2} oxidizes the Ta(IV)-Ta(IV) bond to yield Ta{sub 3}({mu}{sub 3}-O)(H)({mu}NBu{sup t})({mu}-NMe{sub 2}){sub 2}(NMe{sub 2}){sub 4}(NBu{sup t}){sub 2} under ligand exchange. Delocalization of d electrons is discussed.

  8. CRAD, Quality Assurance - Los Alamos National Laboratory TA 55...

    Broader source: Energy.gov (indexed) [DOE]

    Quality Assurance - Los Alamos National Laboratory TA 55 SST Facility CRAD, Quality Assurance - Los Alamos National Laboratory TA 55 SST Facility A section of Appendix C to DOE G...

  9. TA-2 Water Boiler Reactor Decommissioning Project

    SciTech Connect (OSTI)

    Durbin, M.E. (ed.); Montoya, G.M.

    1991-06-01T23:59:59.000Z

    This final report addresses the Phase 2 decommissioning of the Water Boiler Reactor, biological shield, other components within the biological shield, and piping pits in the floor of the reactor building. External structures and underground piping associated with the gaseous effluent (stack) line from Technical Area 2 (TA-2) Water Boiler Reactor were removed in 1985--1986 as Phase 1 of reactor decommissioning. The cost of Phase 2 was approximately $623K. The decommissioning operation produced 173 m{sup 3} of low-level solid radioactive waste and 35 m{sup 3} of mixed waste. 15 refs., 25 figs., 3 tabs.

  10. Microstructure and mechanical properties of Ti-40 wt pct Ta (Ti-15 at. pct Ta)

    SciTech Connect (OSTI)

    Cotton, J.D.; Bingert, J.F.; Dunn, P.S.; Patterson, R.A. (Los Alamos National Lab., NM (United States))

    1994-03-01T23:59:59.000Z

    Of the [beta]-isomorphous Ti-X alloy systems, Ti-Ta is one of the least studied. In the current work, the microstructure and mechanical properties of Ti-40 wt pct Ta (Ti-15 at. pct Ta) are investigated. Annealing at 810 C produces a two-phase microstructure consisting of Ti-rich [alpha] idiomorphs in a continuous Ta-rich [beta] matrix; this suggest the [beta]-transus temperature is higher than indicated by the most recently published phase diagram. Water quenching from 810 C caused the [beta] phase to partially transform to orthorhombic martensite ([alpha][double prime]), while furnace cooling yields secondary [alpha]. The primary [alpha] formed isothermally remains unchanged in both cases. Subsequent aging causes transformation of the martensite to type 1 [alpha] plus residual [beta], with a corresponding increase in strength and decrease in ductility. The maximum ductility (20 pct elongation) occurs in the water-quenched condition in which metastable [beta] is retained. Analysis of the true stress-true strain data suggests that transformation-induced plasticity may contribute to the enhanced ductility of the water-quenched material.

  11. Surface Treatments of Nb by Buffered Electropolishing

    SciTech Connect (OSTI)

    Wu, Andy T. [JLAB; Rimmer, Robert A. [JLAB; Ciovati, Gianluigi [JLAB; Manus, Robert L. [JLAb; Reece, Charles E. [JLAB; Williams, J. S. [JLAB; Eozénou, F. [CEA, Gif-sur-Yvette; Jin, S. [PKU/IHIP, Beijing; Lin, L. [PKU/IHIP, Beijing; Lu, X.Y. [PKU/IHIP, Beijing; Mammosser, John D. [JLAB; Wang, E. [BNL

    2009-11-01T23:59:59.000Z

    Buffered electropolishing (BEP) is a Nb surface treatment technique developed at Jefferson Lab1. Experimental results obtained from flat Nb samples show2-4 that BEP can produce a surface finish much smoother than that produced by the conventional electropolishing (EP), while Nb removal rate can be as high as 4.67 ?m/min. This new technique has been applied to the treatments of Nb SRF single cell cavity employing a vertical polishing system5 constructed at JLab as well as a horizontal polishing system at CEA Saclay. Preliminary results show that the accelerating gradient can reach 32 MV/m for a large grain cavity and 26.7 MV/m for a regular grain cavity. In this presentation, the latest progresses from the international collaboration between Peking University, CEA Saclay, and JLab on BEP will be summarized.

  12. Energetic condensation growth of Nb thin films

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Krishnan, M.; Valderrama, E.; James, C.; Zhao, X.; Spradlin, J.; Feliciano, A-M Valente; Phillips, L.; Reece, C. E.; Seo, K.; Sung, Z. H.

    2012-03-01T23:59:59.000Z

    This paper describes energetic condensation growth of Nb films using a cathodic arc plasma, whose 60–120 eV ions penetrate a few monolayers into the substrate and enable sufficient surface mobility to ensure that the lowest energy state (crystalline structure with minimal defects) is accessible to the film. Heteroepitaxial films of Nb were grown on ?-plane sapphire and MgO crystals with good superconducting properties and crystal size (10??mm × 20??mm ) limited only by substrate size. The substrates were heated to temperatures of up to 700°C and coated at 125°C, 300°C, 500°C, and 700°C . Film thickness was varied from ?0.25???m to >3???m . Residual resistivity ratio (RRR) values (up to a record (RRR)=587 on MgO and (RRR)=328 on ?-sapphire) depend strongly on substrate annealing and deposition temperatures. X-ray diffraction spectra and pole figures reveal that RRR increases as the crystal structure of the Nb film becomes more ordered, consistent with fewer defects and, hence, longer electron mean-free path. A transition from Nb(110) to Nb(100) orientation on the MgO(100) lattice occurs at higher temperatures. This transition is discussed in light of substrate heating and energetic condensation physics. Electron backscattered diffraction and scanning electron microscope images complement the XRD data.

  13. Magnetization anomaly of Nb3Al strands and instability of Nb3Al Rutherford cables

    SciTech Connect (OSTI)

    Yamada, Ryuji; /Fermilab; Kikuchi, Akihiro; /Tsukuba Magnet Lab; Wake, Masayoshi; /KEK, Tsukuba

    2006-08-01T23:59:59.000Z

    Using a Cu stabilized Nb{sub 3}Al strand with Nb matrix, a 30 meter long Nb{sub 3}Al Rutherford cable was made by a collaboration of Fermilab and NIMS. Recently the strand and cable were tested. In both cases instability was observed at around 1.5 Tesla. The magnetization of this Nb{sub 3}Al strand was measured first using a balanced coil magnetometer at 4.2 K. Strands showed an anomalously large magnetization behavior around at 1.6 T, which is much higher than the usual B{sub c2} {approx} 0.5 Tesla (4.2 K) of Nb matrix. This result is compared with the magnetization data of short strand samples using a SQUID magnetometer, in which a flux-jump signal was observed at 0.5 Tesla, but not at higher field. As a possible explanation for this magnetization anomaly, the interfilament coupling through the thin Nb films in the strands is suggested. The instability problem observed in low field tests of the Nb{sub 3}Al Rutherford cables is attributed to this effect.

  14. Silver delafossite nitride, AgTaN{sub 2}?

    SciTech Connect (OSTI)

    Miura, Akira [Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen (Germany); Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853 (United States); Lowe, Michael; Leonard, Brian M.; Subban, Chinmayee V. [Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853 (United States); Masubuchi, Yuji; Kikkawa, Shinichi [Graduate School of Engineering, Hokkaido University, N13W8, Kita-ku Sapporo 060-8628 (Japan); Dronskowski, Richard [Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen (Germany); Hennig, Richard G. [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States); Abruna, Hector D. [Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853 (United States); DiSalvo, Francis J., E-mail: fjd3@cornell.ed [Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853 (United States)

    2011-01-15T23:59:59.000Z

    A new silver nitride, AgTaN{sub 2}, was synthesized from NaTaN{sub 2} by a cation-exchange reaction, using a AgNO{sub 3}-NH{sub 4}NO{sub 3} flux at 175 {sup o}C. Its crystal structure type is delafossite (R3-bar m) with hexagonal lattice parameters of a=3.141(3) A, c=18.81(2) A, in which silver is linearly coordinated to nitrogen. Energy dispersive X-ray analysis and combustion nitrogen/oxygen analysis gave a composition with atomic ratios of Ag:Ta:N:O as 1.0:1.2(1):2.1(1):0.77(4), which is somewhat Ta rich and indicates some oxide formation. The X-ray photoelectron spectroscopy analysis showed a Ta- and O-rich surface and transmission electron microscope observation exhibited aggregates of ca. 4-5 nm-sized particles on the surface, which are probably related to the composition deviation from a AgTaN{sub 2}. The lattice parameters of stoichiometric AgTaN{sub 2} calculated by density functional theory agree with the experimental ones, but the possibility of some oxygen incorporation and/or silver deficiency is not precluded. -- Graphical abstract: A delafossite silver nitride, AgTaN{sub 2}, was synthesized from NaTaN{sub 2} by a cation-exchange reaction using a AgNO{sub 3}-NH{sub 4}NO{sub 3} flux. It contains N-Ag-N linear bonding. Display Omitted

  15. Electrochemical corrosion behavior of biomedical Ti22Nb and Ti22Nb6Zr alloys in saline medium

    E-Print Network [OSTI]

    Zheng, Yufeng

    Electrochemical corrosion behavior of biomedical Ti­22Nb and Ti­22Nb­6Zr alloys in saline medium B addition and potentiodynamic polarization on the microstructure and corrosion resistance of Ti­22Nb and Ti­22Nb­6Zr alloy samples.The corrosion tests were carried out in 0.9% NaCl at 37 8C and neutral p

  16. TA Position Available Fall Quarter 2014 Immediate Opening

    E-Print Network [OSTI]

    Bogyo, Matthew

    in the development of course and workshop content and materials · Assist with the identification, invitationTA Position Available ­ Fall Quarter 2014 Immediate Opening Career Transitions with facilitation of panel/group discussions · Prepare and distribute marketing materials to departments

  17. TA-53 UNREVIEWED SAFETY ISSUE SCREENING AND DETERMINATION PROCESS

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

    3 UNREVIEWED SAFETY ISSUE SCREENING AND DETERMINATION PROCESS TRAINING WORKSHEET CT-TA53-FRM-505-R00 102011 Page 1 of 3 LA-UR-12-10162 TRAINEE NAME: Z NUMBER: GROUP: PURPOSE AND...

  18. DB-Netz AG Offices

    High Performance Buildings Database

    Hamm, Germany The new office building for DB Netz AG was designed by the collaborative team of Architrav Architects and the Buildings Physics and Technical Building Services group of the University of Karlsruhe. The team developed an energy efficient building concept for the 64,304 sqft office building, located in Hamm, Germany. The design concept of the building is dominated by architectural solutions for ventilation, cooling and lighting. Use of HVAC and electric lighting is minimized as much as possible.

  19. I. Top 20 TA Traps 83 II. Team Meeting Guidelines 85

    E-Print Network [OSTI]

    Minnesota, University of

    Other Teaching Resources Page I. Top 20 TA Traps 83 II. Team Meeting Guidelines 85 III. TA Office I. Top 20 TA Traps This list has been compiled by mentor TAs to help you avoid some common pitfalls of being a TA. These are the top twenty things TAs do that interfere with the work of teaching. General

  20. LIMITS OF Nb3Sn ACCELERATOR MAGNETS

    SciTech Connect (OSTI)

    Caspi, Shlomo; Ferracin, Paolo

    2005-05-01T23:59:59.000Z

    Pushing accelerator magnets beyond 10 T holds a promise of future upgrades to machines like the Tevatron at Fermilab and the LHC at CERN. Exceeding the current density limits of NbTi superconductor, Nb{sub 3}Sn is at present the only practical superconductor capable of generating fields beyond 10 T. Several Nb{sub 3}Sn pilot magnets, with fields as high as 16 T, have been built and tested, paving the way for future attempts at fields approaching 20 T. High current density conductor is required to generate high fields with reduced conductor volume. However this significantly increases the Lorentz force and stress. Future designs of coils and structures will require managing stresses of several 100's of MPa and forces of 10's of MN/m. The combined engineering requirements on size and cost of accelerator magnets will involve magnet technology that diverges from the one currently used with NbTi conductor. In this paper we shall address how far the engineering of high field magnets can be pushed, and what are the issues and limitations before such magnets can be used in particle accelerators.

  1. Resistive switching of a TaO{sub x}/TaON double layer via ionic control of carrier tunneling

    SciTech Connect (OSTI)

    Jeon, Heeyoung; Park, Jingyu; Kim, Hyunjung [Department of Nano-Scale Semiconductor Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Jang, Woochool; Song, Hyoseok [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Kang, Chunho [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); FAB Manufacturing Division, SK Hynix Inc., 2091, Gyeongchung-daero, Bubal-eub, Icheon-si, Gyeonggi-do 167-701 (Korea, Republic of); Seo, Hyungtak, E-mail: hseo@ajou.ac.kr [Department of Materials Science and Engineering and Department of Energy Systems Research, Ajou University, Suwon 443-739 (Korea, Republic of); Jeon, Hyeongtag, E-mail: hjeon@hanyang.ac.kr [Department of Nano-Scale Semiconductor Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2014-04-14T23:59:59.000Z

    Resistance random access memory (RRAM) is an attractive candidate for future non-volatile memory due to its superior features. As the oxide thickness is scaled down, the charge transport mechanism is also subject to the transition from hopping to tunneling dominant process, which is critically related to the interfacial electronic band structure. A TaO{sub x}/TaON double layer-based RRAM is fabricated and characterized in this work. Upon TaON insertion at the lower interface, the improved switching behavior is observed. The TaON at the bottom electrode interface blocks oxygen vacancy percolation due to strong N-O bonds and also modifies interfacial band alignment to lower the injected electron energy from bottom electrode due to higher tunneling barrier height than that of TaO{sub x}/Pt. This study suggested that a defect-minimized insertion layer like TaON with a proper interfacial band alignment is pivotal in RRAM for the effective ionic control of carrier tunneling resulting in non-linear I-V behavior with improved properties.

  2. LARP Long Nb3Sn Quadrupole Design.

    SciTech Connect (OSTI)

    Ambrosio,G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Chlachidize, G.; Dietderich, D.; Feher, S.; Felice, H.; Ferracin, P.; Ghosh, A.; Hafalia, A.R.; Hannaford, C.R.; Kashikhin, V.V.; Kerby, J.; Lamm, M.; Lietzke, A.; McInturff, A.; Muratore, J.; Nobrega, F.; Novitsky, I.; Sabbi, G.L.; Schmalzle, J.; Tartaglia, M.; Turrioni, D.; Wanderer, P.; Whitson, G.; Zlobin, A.V.

    2007-08-27T23:59:59.000Z

    A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4m-long quadrupole magnets (LQ) wound with Nb{sub 3}Sn conductor. The goal of these magnets is to be a proof of principle that Nb{sub 3}Sn is a viable technology for a possible LHC luminosity upgrade. The design of the LQ is based on the design of the LARP Technological Quadrupoles, presently under development at FNAL and LBNL, with 90-mm aperture and gradient higher than 200 T/m. The design of the first LQ model will be completed by the end of 2007 with the selection of a mechanical design. In this paper we present the coil design addressing some fabrication technology issues, the quench protection study, and three designs of the support structure.

  3. LARP Long Nb3Sn Quadrupole Design

    SciTech Connect (OSTI)

    Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Chlachidize, G.; Dietderich, D.; Feher, S.; Ferracin, P.; Ghosh, A.; Hafalia, R.; Hannaford, R.; Kashikhin, V.V.; Kerby, J.; Lamm, M.; Lietzke, A.; McInturff, A.; Muratore, J.; Nobrega, F.; Novitsky, I.; Sabbi, G.L.; Schmalzle, J.; Tartaglia, M.; Turrioni, D.; Wanderer, P.; Whitson, G.; Zlobin, A.V.

    2008-06-01T23:59:59.000Z

    A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4m-long quadrupole magnets (LQ) wound with Nb{sub 3}Sn conductor. The goal of these magnets is to be a proof of principle that Nb{sub 3}Sn is a viable technology for a possible LHC luminosity upgrade. The design of the LQ is based on the design of the LARP Technological Quadrupoles, presently under development at FNAL and LBNL, with 90-mm aperture and gradient higher than 200 T/m. The design of the first LQ model will be completed by the end of 2007 with the selection of a mechanical design. In this paper we present the coil design addressing some fabrication technology issues, the quench protection study, and three designs of the support structure.

  4. MongoDB at NERSC

    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 Your1 SECTIONES2008-54174 This manuscript has beenMongoDB

  5. Effects of substrate temperature on properties of NbNx films grown on Nb by pulsed laser deposition

    SciTech Connect (OSTI)

    Ashraf Hassan Farha, Ali Oguz Er, Yüksel Ufuktepe, Ganapati Myneni, Hani E. Elsayed-Ali

    2011-12-01T23:59:59.000Z

    NbN{sub x} films were deposited on Nb substrate using pulsed laser deposition. The effects of substrate deposition temperature, from room temperature to 950 C, on the preferred orientation, phase, and surface properties of NbN{sub x} films were studied by X-ray diffraction, atomic force microscopy, and electron probe micro analyzer. We find that the substrate temperature is a critical factor in determining the phase of the NbN{sub x} films. For a substrate temperature up to 450 C the film showed poor crystalline quality. With temperature increase the film became textured and for a substrate temperature of 650-850 C, mix of cubic {delta}-NbN and hexagonal phases ({beta}-Nb{sub 2}N + {delta}'-NbN) were formed. Films with a mainly {beta}-Nb{sub 2}N hexagonal phase were obtained at deposition temperature above 850 C. The c/a ratio of {beta}-Nb{sub 2}N hexagonal shows an increase with increased nitrogen content. The surface roughness of the NbN{sub x} films increased as the temperature was raised from 450 to 850 C.

  6. "Fine grain Nb tube for SRF cavities"

    SciTech Connect (OSTI)

    Robert E. Barber

    2012-07-08T23:59:59.000Z

    Superconducting radio frequency (SRF) cavities used in charged particle linear accelerators, are currently fabricated by deep drawing niobium sheets and welding the drawn dishes together. The Nb sheet has a non-uniform microstructure, which leads to unpredictable cavity shape and surface roughness, and inconsistent "spring-back" during forming. In addition, weld zones cause hot spots during cavity operation. These factors limit linear accelerator performance and increase cavity manufacturing cost. Equal channel angular extrusion (ECAE) can be used to refine and homogenize the microstructure of Nb tube for subsequent hydroforming into SRF cavities. Careful selection of deformation and heat treatment conditions during the processing steps can give a uniform and consistent microstructure in the tube, leading to improved deformability and lower manufacturing costs. Favorable microstructures were achieved in short test samples of RRR Nb tube, which may be particularly suitable for hydroforming into SRF cavity strings. The approach demonstrated could be applicable to microstructure engineering of other tube materials including tantalum, titanium, and zirconium.

  7. Evaluation of airflow patterns in 2706-T and 2706-TA

    SciTech Connect (OSTI)

    DEROSA, D.C.

    1999-08-26T23:59:59.000Z

    The purpose of this study was to evaluate the adequacy of the current placement of fixed head air samplers and continuous air monitors (CAMs) in the 2706-T and 2706-TA Complex. The airflow study consisted of 6 configurations of facility HVAC and HEPA filtration equipment to determine impacts on CAM location. The results of this study provide recommendations based on guidance in DOE G 411.1-8 and NUREG-1400 for placement of fixed head air samplers or CAMS within 2706-T and 2706-TA.

  8. Elastic anisotropy in multifilament Nb3Sn superconducting wires

    E-Print Network [OSTI]

    Scheuerlein, C; Alknes, P; Arnau, G; Bjoerstad, R; Bordini, B

    2015-01-01T23:59:59.000Z

    The elastic anisotropy caused by the texture in the Nb3Sn filaments of PIT and RRP wires has been calculated by averaging the estimates of Voigt and Reuss, using published Nb3Sn single crystal elastic constants and the Nb3Sn grain orientation distribution determined in both wire types by Electron Backscatter Diffraction. At ambient temperature the calculated Nb3Sn E-moduli in axial direction in the PIT and the RRP wire are 130 GPa and 140 GPa, respectively. The calculated E-moduli are compared with tensile test results obtained for the corresponding wires and extracted filament bundles.

  9. Hot-stage transmission electron microscopy study of (Na, K)NbO{sub 3} based lead-free piezoceramics

    SciTech Connect (OSTI)

    Lu, Shengbo, E-mail: shengbo.lu@yahoo.com [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon (Hong Kong); Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Xu, Zhengkui [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon (Hong Kong); Kwok, K. W.; Chan, Helen L. W. [Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

    2014-07-28T23:59:59.000Z

    Hierarchical nanodomains assembled into micron-sized stripe domains, which is believed to be associated with outstanding piezoelectric properties, were observed at room temperature in a typical lead free piezoceramics, (Na{sub 0.52}K{sub 0.48?x})(Nb{sub 0.95?x}Ta{sub 0.05})-xLiSbO{sub 3}, with finely tuned polymorphic phase boundaries (x?=?0.0465) by transmission electron microscopy. The evolution of domain morphology and crystal structure under heating and cooling cycles in the ceramic was investigated by in-situ hot stage study. It is found that the nanodomains are irreversibly transformed into micron-sized rectangular domains during heating and cooling cycles, which lead to the thermal instability of piezoelectric properties of the materials.

  10. Performance analysis of HD1: a 16 Tesla Nb3Sn dipole Magnet

    E-Print Network [OSTI]

    Mattafirri, S.

    2009-01-01T23:59:59.000Z

    Analysis of HD1: A 16 Tesla Nb 3 Sn Dipole Magnet S.of HD1b, an Upgraded 16 Tesla Nb 3 Sn Dipole Magnet”, This

  11. Compositional depth profiling of TaCN thin films

    SciTech Connect (OSTI)

    Adelmann, Christoph; Conard, Thierry; Franquet, Alexis; Brijs, Bert; Munnik, Frans; Burgess, Simon; Witters, Thomas; Meersschaut, Johan; Kittl, Jorge A.; Vandervorst, Wilfried; Van Elshocht, Sven [Imec, B-3001 Leuven (Belgium); Forschungszentrum Dresden-Rossendorf, D-01314 Dresden (Germany); Oxford Instruments NanoAnalysis, High Wycombe, HP12 3SE (United Kingdom); Imec, B-3001 Leuven (Belgium); Imec, B-3001 Leuven, Belgium and Instituut voor Kern- en Stralingsfysica, Katholieke Universiteit Leuven, B-3001 Leuven (Belgium); Imec, B-3001 Leuven (Belgium)

    2012-07-15T23:59:59.000Z

    The composition profiling of thin TaCN films was studied. For the composition profile determination using x-ray photoemission spectrometry (XPS) in combination with Ar sputtering, preferential sputtering effects of N with respect to Ta and C were found to lead to inaccurate elemental concentrations. Sputter yield calculations for the given experimental conditions allowed for the correction of a part of the error, leading to fair accuracy by reference-free measurements. Further improvement of the accuracy was demonstrated by the calibration of the XPS compositions against elastic recoil detection analysis (ERDA) results. For Auger electron spectrometry (AES) in combination with Ar sputtering, accurate results required the calibration against ERDA. Both XPS and AES allowed for a reliable and accurate determination of the compositional profiles of TaCN-based thin films after calibration. Time-of-flight secondary-ion mass spectrometry was also used to assess the composition of the TaCN films. However, the analysis was hampered by large matrix effects due to small unintentional oxygen contents in the films. Energy-dispersive x-ray spectrometry is also discussed, and it is shown that an accurate reference-free measurement of the average film concentration can be achieved.

  12. CRAD, Maintenance- Los Alamos National Laboratory TA 55 SST Facility

    Broader source: Energy.gov [DOE]

    A section of Appendix C to DOE G 226.1-2 "Federal Line Management Oversight of Department of Energy Nuclear Facilities." Consists of Criteria Review and Approach Documents (CRADs) used for an assessment of the Maintenance program at the Los Alamos National Laboratory TA 55 SST Facility.

  13. IWARTIIV IWARIET'TA MARTIN MARIETTA ENERGYSYSTEMS,INC.

    E-Print Network [OSTI]

    Hively, Lee M.

    OAK RIDGE NATIONAL LABORATORY IWARTIIV IWARIET'TA MANAGED BY MARTIN MARIETTA ENERGYSYSTEMS N. E. Clapp C. S. Daw Oak Ridge National Laboratory January 1996 CAUTION This document has not been. Hively N. E. Clapp C. S. Daw Oak Ridge National Laboratory January 1996 Prepared for U.S. Department

  14. Technical Area (TA)-54 Area G Nitrate-Salt Waste Container Response...

    Office of Environmental Management (EM)

    Technical Area (TA)-54 Area G Nitrate-Salt Waste Container Response Instructions Technical Area (TA)-54 Area G Nitrate-Salt Waste Container Response Instructions This document was...

  15. Microstructural Investigations On Ni-Ta-Al Ternary Alloys

    SciTech Connect (OSTI)

    Negache, M. [Laboratoire de Science et Genie des Materiaux Universite of Sciences and Technologies Houari, Boumediene, FGMGP, BP32 El Alia Bab Ezzouar 16111 Algiers (Algeria); Department of Metallurgy, Nuclear Research Center of Algiers, BP 43 Sebala/Draria (Algeria); Taibi, K.; Lounis, Z. [Laboratoire de Science et Genie des Materiaux Universite of Sciences and Technologies Houari, Boumediene, FGMGP, BP32 El Alia Bab Ezzouar 16111 Algiers (Algeria); Souami, N. [Departement of Spetroscopie, Nuclear Research Center of Algiers, 2Bd Frantz Fanon BP399 Algiers (Algeria)

    2010-01-05T23:59:59.000Z

    The Ni-Al-Ta ternary alloys in the Ni-rich part present complex microstructures. They are composed of multiple phases that are formed according to the nominal composition of the alloy, primary Ni(gamma), Ni{sub 3}Al(gamma'), Ni{sub 6}AlTa(tau{sub 3}), Ni{sub 3}Ta(delta) or in equilibrium: two solid phases (gamma'-tau{sub 3}), (tau{sub 3}-delta), (tau{sub 3}-gamma), (gamma-delta) or three solid phases (gamma'-tau{sub 3}-delta). The nature and the volume fraction of these phases give these alloys very interesting properties at high temperature, and this makes them attractive for specific applications. We have developed a series of ternary alloys in electric arc furnace, determining their solidification sequences using Differential Thermal Analysis (DTA), characterized by SEM-EDS, X-ray diffraction and by a microhardness tests. The follow-up results made it possible to make a correlation between the nature of the formed phases and their solidifying way into the Ni{sub 75}Al{sub x}Ta{sub y} (x+y = 25at.%) system, which are varied and complex. In addition to the solid solution Ni (gamma), the formed intermetallics compounds (gamma', tau{sub 3} and delta) has been identified and correlated with a complex balance between phases.We noticed that the hardness increases with the tantalum which has a hardening effect and though the compound Ni{sub 3}Ta(delta) is the hardest. The below results provide a better understanding of the complex microstructure of these alloys.

  16. Proton Hole States of Nb,95,97,99

    E-Print Network [OSTI]

    Bindal, P. K.; Youngblood, David H.; Kozub, R. L.

    1974-01-01T23:59:59.000Z

    -lying proton hole states in the Nb isotopes is from the study of Ohnuma and Yntema. ' Our recent study of hole state analogs of Nb levels in the Mo iso- topes' revealed a dramatic drop in analog state strength, particularly for / =1 states as one pro...

  17. I. Top 20 TA Traps 129 II. Team Meeting Guidelines 131

    E-Print Network [OSTI]

    Minnesota, University of

    Chapter 5 Other Teaching Resources Page I. Top 20 TA Traps 129 II. Team Meeting Guidelines 131 III for TAs 152 #12;#12;Page 129 I. Top 20 TA Traps This list has been compiled by mentor TAs to help you avoid some common pitfalls of being a TA. These are the top twenty things TAs do that interfere

  18. I. Top 20 TA Traps 129 II. Team Meeting Guidelines 131

    E-Print Network [OSTI]

    Minnesota, University of

    Chapter 5 Other Teaching Resources Page I. Top 20 TA Traps 129 II. Team Meeting Guidelines 131 III for TAs 152 #12;#12;I. Top 20 TA Traps This list has been compiled by mentor TAs to help you avoid some common pitfalls of being a TA. These are the top twenty things TAs do that interfere with the work

  19. CryptDB: A Practical Encrypted Relational DBMS

    E-Print Network [OSTI]

    Popa, Raluca Ada

    2011-01-26T23:59:59.000Z

    CryptDB is a DBMS that provides provable and practical privacy in the face of a compromised database server or curious database administrators. CryptDB works by executing SQL queries over encrypted data. At its core are ...

  20. Multiple NaNbO3/Nb2O5 Heterostructure Nanotubes: A New Class of Ferroelectric/Semiconductor

    E-Print Network [OSTI]

    are created inside hollow Nb2O5 nanotubes, forming a novel class of multiple ferroelectric (NaNbO3 multifunctional ferroelectric/semiconductor devices. The scientific and technological interest in tubular nano within the nanotube's hollow. Herein, we employed a nanotube-confined growth strategy for the one

  1. Technical Area V (TA-V) transformation project close-out report.

    SciTech Connect (OSTI)

    Not Available

    2010-07-01T23:59:59.000Z

    Sandia National Laboratories (SNL) Technical Area V (TA-V) has provided unique nuclear experimental environments for decades. The technologies tested in TA-V facilities have furthered the United States Nuclear Weapons program and has contributed to the national energy and homeland security mission. The importance of TA-V working efficiently to produce an attractive and effective platform for experiments should not be underestimated. Throughout its brief history, TA-V has evolved to address multiple and diverse sets of requirements. These requirements evolved over many years; however, the requirements had not been managed nor communicated comprehensively or effectively. A series of programmatic findings over several years of external audits was evidence of this downfall. Today, these same requirements flow down through a new TA-V management system that produces consistently applied and reproducible approaches to work practices. In 2008, the TA-V department managers assessed the state of TA-V services and work activities to understand how to improve customer interfaces, stakeholders perceptions, and workforce efficiencies. The TA-V management team initiated the TA-V Transformation Project after they deemed the pre-June 2008 operational model to be ineffective in managing work and in providing integrated, continuous improvement to TA-V processes. This report summarizes the TA-V Transformation Project goals, activities, and accomplishments.

  2. TA-DA: A TOOL FOR ASTROPHYSICAL DATA ANALYSIS

    SciTech Connect (OSTI)

    Da Rio, Nicola [European Space Agency, Keplerlaan 1, 2200-AG Noordwijk (Netherlands); Robberto, Massimo, E-mail: ndario@rssd.esa.int [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States)

    2012-12-01T23:59:59.000Z

    We present the Tool for Astrophysical Data Analysis (TA-DA), a new software aimed to greatly simplify and improve the analysis of stellar photometric data in comparison with theoretical models, and allow the derivation of stellar parameters from multi-band photometry. Its flexibility allows one to address a number of such problems: from the interpolation of stellar models, or sets of stellar physical parameters in general, to the computation of synthetic photometry in arbitrary filters or units; from the analysis of observed color-magnitude diagrams to a Bayesian derivation of stellar parameters (and extinction) based on multi-band data. TA-DA is available as a pre-compiled Interactive Data Language widget-based application; its graphical user interface makes it considerably user-friendly. In this paper, we describe the software and its functionalities.

  3. Issues for reuse of gloveboxes at LANL TA-55

    SciTech Connect (OSTI)

    Cadwallader, L.C.; Pinson, P.A.; Miller, C.F.

    1998-08-01T23:59:59.000Z

    This report is a summary of issues that face plutonium glovebox designers and users at the Los Alamos National Laboratory (LANL) Technical Area 55 (TA-55). Characterizing the issues is a step in the task of enhancing the next generation glovebox design to minimize waste streams while providing the other design functions. This report gives an initial assessment of eight important design and operation issues that can benefit from waste minimization.

  4. Proton induced fission of 181-Ta at relativistic energies

    E-Print Network [OSTI]

    Y. Ayyad; J. Benlliure; E. Casarejos; H. Álvarez-Pol; A. Bacquias; A. Boudard; M. Caamańo; T. Enqvist; V. Föhr; A. Keli?-Heil; K. Kezzar; S. Leray; C. Paradela; D. Pérez-Loureiro; R. Pleska?; D. Tarrío

    2012-03-07T23:59:59.000Z

    Total fission cross sections of 181-Ta induced by protons at different relativistic energies have been measured at GSI, Darmstadt. The inverse kinematics technique used together with a dedicated set-up, made it possible to determine these cross sections with high accuracy. The new data obtained in this experiment will contribute to the understanding of the fission process at high excitation energies. The results are compared with data from previous experiments and systematics for proton-induced fission cross sections.

  5. Magnetization measurements on multifilamentary Nb/sub 3/Sn and NbTi conductors

    SciTech Connect (OSTI)

    Ghosh, A.K.; Robins, K.E.; Sampson, W.B.

    1984-01-01T23:59:59.000Z

    The effective filament size has been determined for a number of high current Nb/sub 3/Sn multifilamentary composites. In most cases it is much larger than the nominal filament size. For the smallest filaments (approx. 1 micron) the effective size can be as much as a factor of forty times the nominal size. Samples made by the internal tin, bronze route, and jelly roll methods have been examined with filaments in the range one to ten microns. Rate dependent magnetization and flux jumping have been observed in some cases. NbTi composites ranging in filament size from nine to two hundred microns and with copper to super-conductor ratios between 1.6:1 and 7:1 have been examined in the same apparatus. Low field flux jumping was only observed in conductors with very large filaments and relatively little stabilizing copper. 9 references, 6 figures, 3 tables.

  6. Losses in 23 strands NbTi and Nb/sub 3/Sn flat cables

    SciTech Connect (OSTI)

    Polak, M.; Krempasky, L.; Hlasnik, I.; Perot, J.

    1981-09-01T23:59:59.000Z

    Losses in different samples made of 23 strands multifilamentary NbTi and Nb/sub 3/Sn Rutherford type superconducting cables in pulsed magnetic fields were measured using the magnetization technique. Two technologies were used for sample preparation. One reason for this was to simulate the different winding structure of the pulsed magnets. Another reason was to obtain the samples with different average transverse resistivity across the unsoldered cable. For comparison, one sample, having a low average transverse resistivity, was made of the soldered cable. The influence of the cable pieces length, used for samples, on the rate dependent losses is demonstrated. Problems concerning the measurement of the time constant of the rate dependent magnetization are discussed. 4 refs.

  7. RHQT Nb3Al 15-Tesla magnet design study

    SciTech Connect (OSTI)

    Yamada, R.; Ambrosio, G.; Barzi, E.; Kashikin, V.; Kikuchi, A.; Novitski, I.; Takeuchi, T.; Wake, M.; Zlobin, A.; /Fermilab /NIMC, Tsukuba /KEK, Tsukuba

    2005-09-01T23:59:59.000Z

    Feasibility study of 15-Tesla dipole magnets wound with a new copper stabilized RHQT Nb{sub 3}Al Rutherford cable is presented. A new practical long copper stabilized RHQT Nb{sub 3}Al strand is presented, which is being developed and manufactured at the National Institute of Material Science (NIMS) in Japan. It has achieved a non-copper J{sub c} of 1000A/mm{sup 2} at 15 Tesla at 4.2K, with a copper over non-copper ratio of 1.04, and a filament size less than 50 microns. For this design study a short Rutherford cable with 28 Nb{sub 3}Al strands of 1 mm diameter will be fabricated late this year. The cosine theta magnet cross section is designed using ROXIE, and the stress and strain in the coil is estimated and studied with the characteristics of the Nb{sub 3}Al strand. The advantages and disadvantages of the Nb{sub 3}Al cable are compared with the prevailing Nb{sub 3}Sn cable from the point of view of stress-strain, J{sub c}, and possible degradation of stabilizer due to cabling. The Nb{sub 3}Al coil of the magnet, which will be made by wind and react method, has to be heat treated at 800 degree C for 10 hours. As preparation for the 15 Tesla magnet, a series of tests on strand and Rutherford cables are considered.

  8. Using SciDB to Support Photon Science Data Analysis

    SciTech Connect (OSTI)

    Becla, Jack; Wang, Daniel; lim, Kian-Tat; /SLAC

    2012-02-15T23:59:59.000Z

    Array data analytic systems like SciDB hold great potential to accelerate processing data from SLAC's Linac Coherent Light Source and other experiments. SciDB is unique in its ability to integrate storage and processing of array data efficiently, providing both space-efficient storage and out-of-memory efficient parallel array processing. We describe a recent effort to leverage SciDB to store and process LCLS data. The work includes development of software to import data into SciDB, subsequent benchmarks, and interactive manipulation of data in SciDB.

  9. Niobium-Arsenic Zintl Phases: A6NbAs5 (A ) K, Rb, Cs), K6NbTlAs4, and K8NbPbAs5 with Edge-Bridged Niobium-Centered Tetrahedra of

    E-Print Network [OSTI]

    Niobium-Arsenic Zintl Phases: A6NbAs5 (A ) K, Rb, Cs), K6NbTlAs4, and K8NbPbAs5 with Edge-Bridged Niobium-Centered Tetrahedra of Arsenic, [NbAs4M]n- Where M ) As, Tl, Pb Franck Gascoin and Slavi C. Sevov into exploring this apparent readiness of niobium to react with arsenic and form tetrahedral species, and more

  10. Quench margin measurement in Nb3Sn quadrupole magnet

    SciTech Connect (OSTI)

    Kashikhin, V.V.; Bossert, R.; Chlachidze, G.; Lamm, M.; Novitski, I.; Zlobin, A.V.; /Fermilab

    2008-08-01T23:59:59.000Z

    One of the possible practical applications of the Nb{sub 3}Sn accelerator magnets is the LHC luminosity upgrade that involves replacing the present NbTi focusing quadrupoles in two high-luminosity interaction regions (IR). The IR magnets are exposed to strong radiation from the interaction point that requires a detailed investigation of the magnet operating margins under the expected radiation-induced heat depositions. This paper presents the results of simulation and measurement of quench limits and temperature margins for a Nb{sub 3}Sn model magnet using a special midplane strip heater.

  11. Test of Two NB Superstructure Prototypes

    SciTech Connect (OSTI)

    Sekutowicz, J.

    2004-04-16T23:59:59.000Z

    An alternative layout of the TESLA linear collider [1], based on weakly coupled multi-cell superconducting structures (superstructures), significantly reduces investment cost due to a simplification in the RF system of the main accelerator. In January 1999, preparation of the beam test of the superstructure began in order to prove the feasibility of this layout. Progress in the preparation was reported frequently in Proceedings of TESLA Collaboration Meetings. Last year, two superstructures were installed in the TESLA Test Facility (TTF) linac at DESY to experimentally verify: methods to balance the accelerating gradient in a weakly coupled system, the stability of the energy gain for the entire train of bunches in macro-pulses and the damping of Higher Order Modes (HOMs). We present results of the first cold and beam test of these two Nb prototypes.

  12. Anisotropic giant magnetoresistance in NbSb?

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wang, Kefeng [Brookhaven National Lab. (BNL), Upton, NY (United States); Graf, D. [Florida State Univ., Tallahassee, FL (United States); Li, Lijun [Brookhaven National Lab. (BNL), Upton, NY (United States); Wang, Limin [Brookhaven National Lab. (BNL), Upton, NY (United States); Petrovic, C. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-12-05T23:59:59.000Z

    We report large transverse magnetoreistance (the magnetoresistant ratio ~ 1.3 × 10?% in 2 K and 9 T field, and 4.3 × 10?% in 0.4 K and 32 T field, without saturation) and field-induced metal semiconductor-like transition in NbSb?. Magnetoresistance is significantly suppressed but the metal-semiconductor-like transition persists when the current is along the ac-plane. The sign reversal of the Hall resistivity and Seebeck coefficient in the field, plus the electronic structure reveal the coexistence of a small number of holes with very high mobility and a large number of electrons with low mobility. The large MR is attributed to the change of the Fermi surface induced by the magnetic field in addition to the high mobility metal.

  13. Anisotropic giant magnetoresistance in NbSb?

    SciTech Connect (OSTI)

    Wang, Kefeng [Brookhaven National Lab. (BNL), Upton, NY (United States); Graf, D. [Florida State Univ., Tallahassee, FL (United States); Li, Lijun [Brookhaven National Lab. (BNL), Upton, NY (United States); Wang, Limin [Brookhaven National Lab. (BNL), Upton, NY (United States); Petrovic, C. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-12-05T23:59:59.000Z

    We report large transverse magnetoreistance (the magnetoresistant ratio ~ 1.3 × 10?% in 2 K and 9 T field, and 4.3 × 10?% in 0.4 K and 32 T field, without saturation) and field-induced metal semiconductor-like transition in NbSb?. Magnetoresistance is significantly suppressed but the metal-semiconductor-like transition persists when the current is along the ac-plane. The sign reversal of the Hall resistivity and Seebeck coefficient in the field, plus the electronic structure reveal the coexistence of a small number of holes with very high mobility and a large number of electrons with low mobility. The large MR is attributed to the change of the Fermi surface induced by the magnetic field in addition to the high mobility metal.

  14. Anisotropic giant magnetoresistance in NbSb?

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wang, Kefeng; Graf, D.; Li, Lijun; Wang, Limin; Petrovic, C.

    2014-12-05T23:59:59.000Z

    We report large transverse magnetoreistance (the magnetoresistant ratio ~ 1.3 × 10?% in 2 K and 9 T field, and 4.3 × 10?% in 0.4 K and 32 T field, without saturation) and field-induced metal semiconductor-like transition in NbSb?. Magnetoresistance is significantly suppressed but the metal-semiconductor-like transition persists when the current is along the ac-plane. The sign reversal of the Hall resistivity and Seebeck coefficient in the field, plus the electronic structure reveal the coexistence of a small number of holes with very high mobility and a large number of electrons with low mobility. The large MR is attributed tomore »the change of the Fermi surface induced by the magnetic field in addition to the high mobility metal.« less

  15. Characterization of Nb?Sn superconducting strand under pure bending

    E-Print Network [OSTI]

    Harris, David L., S.M. Massachusetts Institute of Technology

    2005-01-01T23:59:59.000Z

    Characterizing the strain-dependent behavior of technological Nb?Sn superconducting strand has been an important subject of research for the past 25 years. Most of the effort has focused on understanding the uniaxial tension ...

  16. In situ NiTi/Nb(Ti) composite

    SciTech Connect (OSTI)

    Jiang, Daqiang, E-mail: dq80jiang@126.com; Cui, Lishan; Jiang, Jiang; Zheng, Yanjun

    2013-12-15T23:59:59.000Z

    Graphical abstract: - Highlights: • In situ NiTi/Nb(Ti) composites were fabricated. • The transformation temperature was affected by the mixing Ti:Ni atomic ratios. • The NiTi component became micron-scale lamella after forging and rolling. • The composite exhibited high strength and high damping capacity. - Abstract: This paper reports on the creation of a series of in situ NiTi/Nb(Ti) composites with controllable transformation temperatures based on the pseudo-binary hypereutectic transformation of NiTi–Nb system. The composite constituent morphology was controlled by forging and rolling. It is found that the thickness of the NiTi lamella in the composite reached micron level after the hot-forging and cold-rolling. The NiTi/Nb(Ti) composite exhibited high damping capacity as well as high yield strength.

  17. Critical Current Metrology for Nb3Sn Conductor Development

    SciTech Connect (OSTI)

    Goodrich, Loren F. [NIST

    2013-12-13T23:59:59.000Z

    The research is focused on the variable temperature studies of high-performance Nb3Sn and other high-field conductors for the next-generation of HEP magnets.

  18. Nb3Sn Quadrupole Magnets for the LHC IR

    SciTech Connect (OSTI)

    Sabbi, G.; Caspi, S.; Chiesa, L.; Coccoli, M.; Dietderich, D.r.; Ferracin, P.; Gourlay, S.A.; Hafalia, R.R.; Lietzke, A.F.; McInturff, A.D.; Scanlan, R.M.

    2001-08-01T23:59:59.000Z

    The development of insertion quadrupoles with 205 T/m gradient and 90 mm bore represents a promising strategy to achieve the ultimate luminosity goal of 2.5 x 10{sup 34} cm{sup -2}s{sup -1} at the Large Hadron Collider (LHC). At present, Nb{sub 3}Sn is the only practical conductor which can meet these requirements. Since Nb{sub 3}Sn is brittle, and considerably more strain sensitive than NbTi, the design concepts and fabrication techniques developed for NbTi magnets need to be modified appropriately. In addition, IR magnets must provide high field quality and operate reliably under severe radiation loads. The results of conceptual design studies addressing these issues are presented.

  19. Performance Comparison of Nb3Sn Magnets at LBNL

    E-Print Network [OSTI]

    Chiesa, L.

    2011-01-01T23:59:59.000Z

    2LCOI SC-MAG#722 LBNL-49917 Performance Comparison ofNb 3 Sn Magnets at LBNL L. Chiesa, S. Caspi, M . Coccoli,the Superconducting Magnet Group at LBNL has been developing

  20. Synthesis and Characterization of Nonbanded U-Nb Plate Material

    SciTech Connect (OSTI)

    R. E. Hackenberg, R. M Aikin, Jr., J. A. Balog, B. L. Bingham, R. Casey, A. Casteel, I. Cordova, R. Forsyth, F. G. Garcia, D. Guidry, D. L. Hammon, W. L. Hults, D. R. Korzekwa, A. M. Kelly, M. W. Kolby, K. A. Lao, J. C. Lashley, M. F. Lopez, R. McCabe, D. E. Nye, P. A. Papin, S. W. Quintana, J. L. Smith, D. F. Teter, D. J. Thoma, T. Tucker, P. K. Tubesing, R. R. Trujillo, C. J. Vigil, and H. M. Volz

    2007-01-22T23:59:59.000Z

    This report describes the synthesis and characterization of four plates, two each of U-5.5Nb and U-7.5Nb (nominal wt%) for aging studies described elsewhere. The plates were induction melted and cast into graphite molds that were unheated and {approx}0.5 inches thick to maximize the cooling rate and minimize large length-scale Nb segregation (banding). Microstructural images and electron microprobe traces observed after various processing stages, including casting, hot rolling, and homogenizing are documented. The as-cast microsegregation assumed the form of an isotropic cellular structure, with an amplitude of 3-15 wt% Nb and 40-50 micron-length scales. Subsequent thermomechanical processing was shown to be sufficient to attain Nb compositional homogeneity on local scales of hundreds of microns. The results of chemical analysis and other characterization methods are given. The principal impurity elements (of the 40+ elements measured) were carbon, boron, oxygen, tantalum, and iron. In all four plates, after homogenization, the Nb distribution across the entire plate cross-section showed minima at the plate faces and a broad maximum in the center, the differential being 0.5-0.7 wt% in U-7.5Nb and 0.2-0.5 wt% in U-5.5Nb. None of the impurity elements showed statistically significant variations between the center 50% of the plate volume vs the outer 25%. These plates were considered nonbanded and compositionally homogeneous for their proposed use because the required tensile, metallographic, and dilatometer specimens could be extracted from the fairly homogeneous center portion of the plate cross-section. Characterization of the phases and their transition temperatures by x-ray diffraction and dilatometry in rapidly quenched specimens from the final product confirmed that the microstructure of this plate material was suitable for the intended aging studies. The as-quenched tensile response from multiple specimens taken from each plate showed some variability, especially in the ultimate tensile strength and elongation to failure. In general, U-5.5Nb has higher strength and less ductility than U-7.5Nb, though both alloys exhibited the double yield behavior characteristic of banded U-6Nb.

  1. Growth and microstructure evolution of the Nb{sub 2}Al-Al{sub 3}Nb eutectic in situ composite

    SciTech Connect (OSTI)

    Rios, C.T. [State University of Campinas, P.O. Box 6122, Campinas, SP 13083-970 (Brazil); Ferrandini, P.L. [Centro Universitario da FEI, C.P.85, CEP:09850-901, SP-Brasil (Brazil); Milenkovic, S. [State University of Campinas, P.O. Box 6122, Campinas, SP 13083-970 (Brazil); Caram, R. [State University of Campinas, P.O. Box 6122, Campinas, SP 13083-970 (Brazil)]. E-mail: rcaram@fem.unicamp.br

    2005-03-15T23:59:59.000Z

    In situ composite materials obtained by directional growth of eutectic alloys usually show improved properties, that make them potential candidates for high temperature applications. The eutectic alloy found in the Al-Nb system is composed of the two intermetallic phases Al{sub 3}Nb (D0{sub 22}) and Nb{sub 2}Al (D8{sub b}). This paper describes the directional solidification of an Al-Nb eutectic alloy using a Bridgman type facility at growth rates varying from 1.0 to 2.9 cm/h. Longitudinal and transverse sections of grown samples were characterized regarding the solidification microstructure by using optical and scanning electron microscopy, energy dispersive spectroscopy (EDS) and X-ray diffraction. Despite both phases being intermetallic compounds, the eutectic microstructure obtained was very regular. The results obtained were discussed regarding the effect of the growth rate on the microstructure, lamellar-rod transition and variation of phase volume fraction.

  2. TaC Studios New Construction Test House

    SciTech Connect (OSTI)

    Butler, T.; Curtis, O.; Kim, E.; Roberts, S.; Stephenson, R.

    2013-03-01T23:59:59.000Z

    As part of the NAHB Research Center Industry Partnership, Southface partnered with TaC Studios, an Atlanta based architecture firm specializing in residential and light commercial design, on the construction of a new test home in Atlanta, GA in the mixed humid climate zone. This home will serve as a model home for the builder partner and addresses Building America energy savings targets through the planning and implementation of a design package will serve as a basis of design for the builder partner's future homes. As a BA test house, this home will be evaluated to detail whole house energy use, end use loads, and HVAC and hot water efficiency.

  3. I. Top 20 TA Traps 123 II. Team Meeting Guidelines 125

    E-Print Network [OSTI]

    Minnesota, University of

    Chapter 5 Other Teaching Resources Page I. Top 20 TA Traps 123 II. Team Meeting Guidelines 125 III.0.0 143 IX. Useful Information for TAs 147 #12;#12;Page 123 I. Top 20 TA Traps This list has been compiled by mentor TAs to help you avoid some common pitfalls of being a TA. These are the top twenty things TAs do

  4. Morphological instability of Ag films caused by phase transition in the underlying Ta barrier layer

    SciTech Connect (OSTI)

    Mardani, Shabnam, E-mail: shabnam.mardani@angstrom.uu.se; Vallin, Örjan; Wätjen, Jörn Timo; Norström, Hans; Olsson, Jörgen; Zhang, Shi-Li, E-mail: shili.zhang@angstrom.uu.se [Solid State Electronics, The Ĺngström Laboratory, Uppsala University, P.O. Box 534, SE-75121 (Sweden)

    2014-08-18T23:59:59.000Z

    Wide-bandgap (WBG) semiconductor technologies are maturing and may provide increased device performance in many fields of applications, such as high-temperature electronics. However, there are still issues regarding the stability and reliability of WBG devices. Of particular importance is the high-temperature stability of interconnects for electronic systems based on WBG-semiconductors. For metallization without proper encapsulation, morphological degradation can occur at elevated temperatures. Sandwiching Ag films between Ta and/or TaN layers in this study is found to be electrically and morphologically stabilize the Ag metallization up to 800?°C, compared to 600?°C for uncapped films. However, the barrier layer plays a key role and TaN is found to be superior to Ta, resulting in the best achieved stability, whereas the difference between Ta and TaN caps is negligible. The ?-to-? phase transition in the underlying Ta barrier layer is identified as the major cause responsible for the morphological instability observed above 600?°C. It is shown that this phase transition can be avoided using a stacked Ta/TaN barrier.

  5. Electrochemical and Electrochromic Properties of Nanoworm-shaped Ta2O5-Pt Thin-Films

    SciTech Connect (OSTI)

    Park, K

    2004-05-18T23:59:59.000Z

    A Ta{sub 2}O{sub 5}-Pt nanostructure electrode was fabricated by means of cosputtering. Worm-like Pt nanoparticles were produced in Ta{sub 2}O{sub 5} matrix as observed by transmission electron microscopy (TEM) and small angle x-ray scattering (SAXS). The electrochemical and electrochromic properties of nanoworm-shaped Ta{sub 2}O{sub 5}-Pt electrode are compared with those of Ta{sub 2}O{sub 5} thin-film electrode without Pt nanoparticles.

  6. Test Results for HD1, a 16 Tesla Nb3Sn Dipole Magnet

    E-Print Network [OSTI]

    Lietzke, A.F.

    2011-01-01T23:59:59.000Z

    Design and Fabrication ofa 16 Tesla Nb 3 Sn Dipole Magnet",Test Results for HD 1, a 16 Tesla Nb 3 Sn Dipole Magnet A.F.and bore fields above 16 Tesla. II. MAGNET FEATURES AND TEST

  7. Poly(ethyleneimine) as a Passivating Agent for Ta Chemical Mechanical Planarization

    E-Print Network [OSTI]

    Suni, Ian Ivar

    enhances the rate of Ta CMP, and in situ studies by electrochemical impedance spectroscopy EIS demonstrate CMP . Studies by electrochemical impedance spectroscopy in a model CMP slurry suggest that PEI forms electrochemistry measurements were performed with a three- electrode setup including a Ta rotating disk electrode

  8. Aluminum-stabilized Nb[sub 3]Sn superconductor

    DOE Patents [OSTI]

    Scanlan, R.M.

    1988-05-10T23:59:59.000Z

    Disclosed are an aluminum-stabilized Nb[sub 3]Sn superconductor and process for producing same, utilizing ultrapure aluminum. Ductile components are co-drawn with aluminum to produce a conductor suitable for winding magnets. After winding, the conductor is heated to convert it to the brittle Nb[sub 3]Sn superconductor phase, using a temperature high enough to perform the transformation but still below the melting point of the aluminum. This results in reaction of substantially all of the niobium, while providing stabilization and react-in-place features which are beneficial in the fabrication of magnets utilizing superconducting materials. 4 figs.

  9. QE data for Pb/Nb deposited photo cathode samples

    E-Print Network [OSTI]

    Sekutowicz, J

    2010-01-01T23:59:59.000Z

    This report outlines progress in the development of photo-cathodes for a hybrid lead/niobium (Pb/Nb) superconducting SRF electron injector. We have coated eight Nb samples with lead to study and determine deposition conditions leading to high quality emitting area. The results show that the oxide layer significantly influences the quantum efficiency (QE) of all measured cathodes. In addition, we learned that although the laser cleaning enhanced the QE substantially, the film morphology was strongly modified. That observation convinced us to make the coatings thicker and therefore more robust.

  10. Aluminum-stabilized Nb/sub 3/Sn superconductor

    DOE Patents [OSTI]

    Scanlan, R.M.

    1984-02-10T23:59:59.000Z

    This patent discloses an aluminum-stabilized Nb/sub 3/Sn superconductor and process for producing same, utilizing ultrapure aluminum. Ductile components are co-drawn with aluminum to produce a conductor suitable for winding magnets. After winding, the conductor is heated to convert it to the brittle Nb/sub 3/Sn superconductor phase, using a temperature high enough to perform the transformation but still below the melting point of the aluminum. This results in reaction of substantially all of the niobium, while providing stabilization and react-in-place features which are beneficial in the fabrication of magnets utilizing superconducting materials.

  11. Summary of the Symposium on Ingot Nb and New Results on Fundamental Studies of Large Grain Nb

    SciTech Connect (OSTI)

    G. Ciovati, P. Dhakal, R. Myneni

    2011-07-01T23:59:59.000Z

    The First International Symposium on the Superconducting Science and Technology of Ingot Niobium was held at Jefferson Lab in September 2010. Significant activities are taking place at laboratories and universities throughout the world to address several aspects related to the science and technology of Ingot Nb: from ingot production to mechanical, thermal and superconducting properties. A summary of the results presented at the Symposium is given in this contribution. New results on the superconducting properties and interstitial impurities content measured in large-grain Nb samples and cavities are briefly highlighted.

  12. Chemical Concentrations in Field Mice from Open-Detonation Firing Sites TA-36 Minie and TA-39 Point 6 at Los Alamos National Laboratory

    SciTech Connect (OSTI)

    Fresquez, Philip R. [Los Alamos National Laboratory

    2011-01-01T23:59:59.000Z

    Field mice (mostly Peromyscus spp.) were collected at two open-detonation (high explosive) firing sites - Minie at Technical Area (TA) 36 and Point 6 at TA-39 - at Los Alamos National Laboratory in August of 2010 and in February of 2011 for chemical analysis. Samples of whole body field mice from both sites were analyzed for target analyte list elements (mostly metals), dioxin/furans, polychlorinated biphenyl congeners, high explosives, and perchlorate. In addition, uranium isotopes were analyzed in a composite sample collected from TA-36 Minie. In general, all constituents, with the exception of lead at TA-39 Point 6, in whole body field mice samples collected from these two open-detonation firing sites were either not detected or they were detected below regional statistical reference levels (99% confidence level), biota dose screening levels, and/or soil ecological chemical screening levels. The amount of lead in field mice tissue collected from TA-39 Point 6 was higher than regional background, and some lead levels in the soil were higher than the ecological screening level for the field mouse; however, these levels are not expected to affect the viability of the populations over the site as a whole.

  13. Design study of 15-Tesla RHQT Nb3Al block type dipole magnet

    SciTech Connect (OSTI)

    Yamada, R.; Ambrosio, G.; Barzi, E.; Kashikin, V.; Kikuchi, A.; Novitski, I.; Takeuchi, T.; Wake, M.; Zlobin, A.; /Fermilab /NIMC, Tsukuba /KEK, Tsukuba

    2005-09-01T23:59:59.000Z

    The design study of the block type 15-Tesla RHQT Nb{sub 3}Al dipole magnet, and its merits over Nb{sub 3}Sn magnets are presented. The copper stabilized RHQT Nb{sub 3}Al strand is now becoming commercially available for the application to the accelerator magnets. A 1 mm diameter RHQT Nb{sub 3}Al strand with filament size about 50 {mu}, non-copper Jc about 1000 A/mm{sup 2} at 15 Tesla at 4.2K, copper ratio of 50%, can now be produced over several hundred meters. The stress and strain characteristics of the Nb{sub 3}Al strand are superior to the Nb{sub 3}Sn strand. Another advantage is that it can tolerate a longitudinal strain up to 0.55%. The RHQT Nb{sub 3}Al Rutherford cable will have less chance of contamination of the stabilizer, compared to Nb{sub 3}Sn cable. These characteristics of the RHQT Nb{sub 3}Al will be beneficial for designing and producing 15-Tesla dipole magnets. An example 15-Tesla magnet cross section, utilizing the RHQT Nb{sub 3}Sn strand is presented. A systematic investigation on RHQT Nb{sub 3}Al strands, its Rutherford cables, and building a small racetrack magnet for cable testing are proposed.

  14. Quantitative analysis of Nb in solution in a microalloyed carburizing steel by electrochemical etching

    SciTech Connect (OSTI)

    Rivas, A.L. [Universidad Simon Bolivar, Valle de Sartenejas-Edificio MEM Piso 2, Departamento Ciencia de los Materiales, Caracas-1080 (Venezuela)], E-mail: alrivas@usb.ve; Matlock, D.K. [Advanced Steel Processing and Product Research Center, Colorado School of Mines, Golden, Colorado 80401 (United States)], E-mail: dmatlock@mines.edu; Speer, J.G. [Advanced Steel Processing and Product Research Center, Colorado School of Mines, Golden, Colorado 80401 (United States)], E-mail: jspeer@mines.edu

    2008-05-15T23:59:59.000Z

    The amount of Nb in solution in a microalloyed carburizing steel (Nb-modified SAE 8620) was evaluated in different heat treated conditions. The test procedure involved electrochemical extraction, filtration and Inductively Coupled Plasma Atomic Emission Spectroscopic (ICP-AES) analysis. Characterization by X-ray diffraction of the residues collected in the filters was also performed. Results showed that Nb in solution tends to hydrolyze during electrolysis in a 10 vol.% HCl electrolyte, giving misleading measurements of the amount of Nb that dissolved during high temperature heat treatment. Hydrolysis of Nb is prevented by the addition of tartaric acid to the electrolyte. In the full dissolution condition, coarse (Ti,Nb)CN was the only precipitate present. Finer (Nb,Ti)C precipitates were observed after heat treating at 1050 deg. C.

  15. Neutron diffraction studies of the Zr/Nb effects on the Nb3Sn phase formation of monofilament wires

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    for Nonferrous Metal Research (NIN) , P.O.Box 51, Xi'an, Shaanxi 710016, P.R.China a soubeyroux with high superconducting properties it is important to improve the kinetics of the diffusion mechanism) of Nb are always used for high field applications [4,5]. Copper in the internal tin process has been

  16. High-strength high-conductivity Cu-Nb microcomposite sheet fabricated via multiple roll bonding

    SciTech Connect (OSTI)

    Jha, S.C.; Delagi, R.G.; Forster, J.A. (Texas Instruments Materials and Control Group, Attleboro, MA (United States)); Krotz, P.D. (Rockwell International Corp., Huntsville, AL (United States))

    1993-01-01T23:59:59.000Z

    Copper-niobium microcomposites are a new class of high-strength high-conductivity materials that have attractive properties for room- and elevated-temperature applications. Since Nb has little solid solubility in Cu, addition of Nb to Cu does not affect its conductivity. Copper-niobium microcomposites are melted and cast so that the microstructure of cast Cu-Nb ingots consists of 1- to 10 [mu]m Nb dendrites uniformly distributed within the copper matrix. Extensive wire drawing with a true processing strain ([eta][gt] 12) of Cu-Nb alloy leads to refinement and elongation of Nb dendrites into 1- to 10 nm-thick filaments. The presence of such fine Nb filaments causes a significant increase in the strength of Cu-Nb wires. The tensile strength of heavily drawn Cu-Nb wires was determined to be significantly higher than the values predicted by the rule of mixtures. This article reports the fabrication of high-strength Cu-Nb microcomposite sheet by multiple roll bonding. It is difficult and impractical to attain high processing strains ([eta][gt]3) by simple cold rolling. In most practical cold-rolling operation, the thickness reduction does not exceed 90 pct ([eta] [approx equal]2). Therefore, innovative processing is required to generate high strength in Cu-Nb microcomposite sheet. Multiple roll bonding of Cu-Nb has been utilized to store high processing strain ( [eta][gt]10) in the material and refine the Nb particle size within the copper matrix. This article describes the microstructure, mechanical properties, and thermal stability of roll-bonded Cu-Nb microcomposite sheet.

  17. Deploy IBM DB2 pureScale feature on IBM Power Benefit from the shared disk architecture of DB2 pureScale

    E-Print Network [OSTI]

    of DB2 pureScale Skill Level: Intermediate Miso Cilimdzic (cilimdzi@ca.ibm.com) DB2 Performance Manager Tivoli® System Automation for Multiplatforms (Tivoli SA MP) software · IBM Reliable Scalable Clustering

  18. Influence of shockwave obliquity on deformation twin formation in Ta

    SciTech Connect (OSTI)

    Gray, George T., III [Los Alamos National Laboratory; Livescu, V [Los Alamos National Laboratory; Cerreta, E K [Los Alamos National Laboratory; Mason, T A [Los Alamos National Laboratory; Maudlin, P J [RETIRED; Bingert, J F [Los Alamos National Laboratory

    2009-02-18T23:59:59.000Z

    Energetic loading subjects a material to a 'Taylor wave' (triangular wave) loading profile that experiences an evolving balance of hydrostatic (spherical) and deviatoric stresses. While much has been learned over the past five decades concerning the propensity of deformation twinning in samples shockloaded using 'square-topped' profiles as a function of peak stress, achieved most commonly via flyer plate loading, less is known concerning twinning propensity during non-I-dimensional sweeping detonation wave loading. Systematic small-scale energetically-driven shock loading experiments were conducted on Ta samples shock loaded with PEFN that was edge detonated. Deformation twinning was quantified in post-mortem samples as a function of detonation geometry and radial position. In the edge detonated loading geometry examined in this paper, the average volume fraction of deformation twins was observed to drastically increase with increasing shock obliquity. The results of this study are discussed in light of the formation mechanisms of deformation twins, previous literature studies of twinning in shocked materials, and modeling of the effects of shock obliquity on the evolution of the stress tensor during shock loading.

  19. A COMPREHENSIVE SPECTROSCOPIC ANALYSIS OF DB WHITE DWARFS

    SciTech Connect (OSTI)

    Bergeron, P.; Wesemael, F.; Dufour, Pierre; Beauchamp, A.; Hunter, C.; Gianninas, A.; Limoges, M.-M.; Dufour, Patrick; Fontaine, G. [Departement de Physique, Universite de Montreal, C.P. 6128, Succ. Centre-Ville, Montreal, QC H3C 3J7 (Canada); Saffer, Rex A. [Strayer University, 234 Mall Boulevard, Suite G-50, King of Prussia, PA 19406 (United States); Ruiz, M. T. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Liebert, James, E-mail: bergeron@astro.umontreal.ca, E-mail: wesemael@astro.umontreal.ca, E-mail: gianninas@astro.umontreal.ca, E-mail: limoges@astro.umontreal.ca, E-mail: dufourpa@astro.umontreal.ca, E-mail: fontaine@astro.umontreal.ca, E-mail: alain.beauchamp@fti-ibis.com, E-mail: chris.hunter@yale.edu, E-mail: rex.saffer@strayer.edu, E-mail: mtruiz@das.uchile.cl [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)

    2011-08-10T23:59:59.000Z

    We present a detailed analysis of 108 helium-line (DB) white dwarfs based on model atmosphere fits to high signal-to-noise optical spectroscopy. We derive a mean mass of 0.67 M{sub sun} for our sample, with a dispersion of only 0.09 M{sub sun}. White dwarfs also showing hydrogen lines, the DBA stars, comprise 44% of our sample, and their mass distribution appears similar to that of DB stars. As in our previous investigation, we find no evidence for the existence of low-mass (M < 0.5 M{sub sun}) DB white dwarfs. We derive a luminosity function based on a subset of DB white dwarfs identified in the Palomar-Green Survey. We show that 20% of all white dwarfs in the temperature range of interest are DB stars, although the fraction drops to half this value above T{sub eff} {approx} 20,000 K. We also show that the persistence of DB stars with no hydrogen features at low temperatures is difficult to reconcile with a scenario involving accretion from the interstellar medium, often invoked to account for the observed hydrogen abundances in DBA stars. We present evidence for the existence of two different evolutionary channels that produce DB white dwarfs: the standard model where DA stars are transformed into DB stars through the convective dilution of a thin hydrogen layer and a second channel where DB stars retain a helium atmosphere throughout their evolution. We finally demonstrate that the instability strip of pulsating V777 Her white dwarfs contains no non-variables, if the hydrogen content of these stars is properly accounted for.

  20. Energy-beam processing studies on Ta/U and Ir/Ta systems. [Laser-and electron-beam melting

    SciTech Connect (OSTI)

    Kaufmann, E.N.; Peercy, P.S.; Jacobson, D.C.; Draper, C.W.; Huegel, F.J.; Echer, C.J.; Makowiecki, D.M.; Balser, J.D.

    1983-11-11T23:59:59.000Z

    Films of Ta metal on uranium and of Ir metal on tantalum have been irradiated and melted by pulses from Q-switched Ruby and frequency-doubled Nd:YAG lasers to investigate the nature of the resulting mixtures in light of the very different binary-phase diagrams of the two systems. In addition, a two-phase Ir-Ta alloy has been surface-processed with CW CO/sub 2/-laser radiation and with an electron beam in order to study microstructure refinement and test the advantage of using alloys as opposed to film-on-substrate combinations for the development of claddings.

  1. Strain tolerances in Nb/sub 3/Sn conductors

    SciTech Connect (OSTI)

    Luhman, T.

    1982-01-01T23:59:59.000Z

    This paper reviews the literature pertinent to the effect of strain on the critical currents of a variety of differently heat-treated multifilamentary Nb/sub 3/Sn superconductors. The dependence of the critical currents on the parameters of uniaxial, tensile, bending, and intrinsic strains, and on temperature and composite ratio variations, is both plotted and analyzed. A review of specific efforts to enhance the strain tolerances of Nb/sub 3/Sn superconductors is given. Those efforts include 1) the approach of minimizing an accomodating plastic flow in the bronze during a cooldown from the reaction heat treatment temperaure by alloying the bronze with Be; 2) the method of jacketing a conductor with stainless steel to enhance the effect R /SUB v/ ; and 3) the ''wind and react'' approach, or the procedure olf vacuum-impregnating the coil windings with epoxy following the reaction heat treatment.

  2. Cr{sub 2}Nb-based alloy development

    SciTech Connect (OSTI)

    Liu, C.T.; Horton, J.A.; Carmichael, C.A.

    1996-05-01T23:59:59.000Z

    This paper summarizes recent progress in developing Cr{sub 2}Nb/Cr(Nb) alloys for structural use in advanced fossil energy conversion systems. Alloy additions were added to control the microstructure and mechanical properties. Two beneficial elements have been identified among all alloying additions added to the alloys. One element is effective in refining the coarse eutectic structure and thus substantially improves the compressive strength and ductility of the alloys. The other element enhances oxidation resistance without sacrificing the ductility. The tensile properties are sensitive to cast defects, which can not be effectively reduced by HIPping at 1450-1580{degrees}C and/or directionally solidifying via a floating zone remelting method.

  3. Low Pressure Hugoniot for U-Nb (6 wt.%)

    SciTech Connect (OSTI)

    Koller, D. D.; Rigg, P. A.; Gray, G. T. III; Jensen, B. J.; Hayes, D. B.; Maestas, J. D. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2006-07-28T23:59:59.000Z

    Over the last several years, many experiments have been conducted to study the dynamic response of U-Nb (6 wt.%) alloy. An understanding of the physical mechanisms governing the behavior of this material is necessary to develop robust physical models for today's hydrocodes. Previous experiments indicate that the dynamic response of this alloy is strongly dependant on the initial microstructure of the material. Using a well characterized material, a series of low pressure shock experiments were conducted at the single stage light gas gun facility at Los Alamos National Laboratory. Time resolved particle velocity measurements were made using VISAR. Absolute VISAR system timing was measured and cross correlated to shock breakout time to allow hugoniot points to be calculated. These shots provide both low pressure Hugoniot points for U-Nb (6 wt.%) alloy and a better constraint on the dynamic material response.

  4. Development of a large aperture Nb3Sn racetrack quadrupolemagnet

    SciTech Connect (OSTI)

    Ferracin, Paolo; Bartlett, Scott E.; Caspi, Shlomo; Dietderich,Daniel R.; Gourlay, Steven A.; Hannaford, Charles R.; Hafalia, AurelioR.; Lietzke, Alan F.; Mattafirri, Sara; McInturff, Alfred D.; Nyman,Mark; Sabbi, Gianluca

    2005-04-14T23:59:59.000Z

    The U.S. LHC Accelerator Research Program (LARP), a collaboration between BNL, FNAL, LBNL, and SLAC, has among its major objectives the development of advanced magnet technology for an LHC luminosity upgrade. The LBNL Superconducting Magnet Group supports this program with a broad effort involving design studies, Nb{sub 3}Sn conductor development, mechanical models, and basic prototypes. This paper describes the development of a large aperture Nb{sub 3}Sn racetrack quadrupole magnet using four racetrack coils from the LBNL Subscale Magnet (SM) Program. The magnet provides a gradient of 95 T/m in a 110 mm bore, with a peak field in the conductor of 11.2 T. The coils are prestressed by a mechanical structure based on a pre-tensioned aluminum shell, and axially supported with aluminum rods. The mechanical behavior has been monitored with strain gauges and the magnetic field has been measured. Results of the test are reported and analyzed.

  5. IntegromeDB: an integrated system and biological search engine

    E-Print Network [OSTI]

    Baitaluk, Michael; Kozhenkov, Sergey; Dubinina, Yulia; Ponomarenko, Julia

    2012-01-01T23:59:59.000Z

    Wright A: Searching the Deep Web. CACM 2008, 51(10):14-15.a semantic, graph based, ‘deep web’ data integration systemIntegromeDB to tap into the Deep Web, the portion of the web

  6. BayesDB : querying the probable implications of tabular data

    E-Print Network [OSTI]

    Baxter, Jay

    2014-01-01T23:59:59.000Z

    BayesDB, a Bayesian database table, lets users query the probable implications of their tabular data as easily as an SQL database lets them query the data itself. Using the built-in Bayesian Query Language (BQL), users ...

  7. Remote data access and analysis using SciDB

    E-Print Network [OSTI]

    Anderson, Alan M., M. Eng. Massachusetts Institute of Technology

    2012-01-01T23:59:59.000Z

    SciDB is an innovative data analysis system that provides fast querying and manipulation of large amounts of time-series, scientific data. This thesis describes the design of a framework that provides a user interface to ...

  8. Fluoride (F) is not taken up by Salmonella typhimurium TA98 (TA98), used for Ames mutagenicity test, unless aluminum (Al) is present

    SciTech Connect (OSTI)

    Ahn, H.W.; Jeffery, E.H. (Univ. of Illinois, Urbana (United States))

    1991-03-11T23:59:59.000Z

    TA98 is commonly used for the Ames test to detect frame-shift mutations. Ames test results for fluoride mutagenicity are controversial. Since Al and F, both present in finished drinking water, form a stable complex, the authors determined the effect of Al on F uptake by TA98 to evaluate any Al effect on Ames test results for F. A known number of TA98 in 0.1M potassium phosphate buffer was incubated with various concentrations of Al, F or aluminum fluoride for 1 hr at 37C in a shaking incubator. The cells were washed twice in potassium phosphate buffer and then resuspended in water. After breaking the cells open by sonication, the resulting supernatant was analyzed for Al by graphite furnace atomic absorption and for F using a F ion-selective electrode. Al accumulated in a concentration-dependent manner to 4.5 ppm then decreased rapidly as the Al was increased to 9 ppm. Intracellular F was below the limit of detection even when the medium contained 590 ppm F. However, F was taken up from media containing greater than 200 ppm F, providing that aluminum was also present. The authors conclude that the Ames test, using TA98, is not suitable for the detection of F mutagenicity.

  9. Performance of Nb3Sn Quadrupole Under High Stress

    SciTech Connect (OSTI)

    Felice, H.; Bajko, M.; Bingham, B.; Bordini, B.; Bottura, L.; Caspi, S.; Rijk, G. De; Dietderich, D.; Ferracin, P.; Giloux, C.; Godeke, A.; Hafalia, R.; Milanese, A.; Rossi, L.; Sabbi, G. L.

    2010-08-01T23:59:59.000Z

    Future upgrades of the Large Hadron Collider (LHC) will require large aperture and high gradient quadrupoles. Nb{sub 3}Sn is the most viable option for this application but is also known for its strain sensitivity. In high field magnets, with magnetic fields above 12 T, the Lorentz forces will generate mechanical stresses that may exceed 200 MPa in the windings. The existing measurements of critical current versus strain of Nb{sub 3}Sn strands or cables are not easily applicable to magnets. In order to investigate the impact of high mechanical stress on the quench performance, a series of tests was carried out within a LBNL/CERN collaboration using the magnet TQS03 (a LHC Accelerator Research Program (LARP) 1-meter long, 90-mm aperture Nb{sub 3}Sn quadrupole). The magnet was tested four times at CERN under various pre-stress conditions. The average mechanical compressive azimuthal pre-stress on the coil at 4.2 K ranged from 120 MPa to 200 MPa. This paper reports on the magnet performance during the four tests focusing on the relation between pre-stress conditions and the training plateau.

  10. Bixbyite- and anatase-type phases in the system Sc-Ta-O-N

    SciTech Connect (OSTI)

    Stork, A.; Schilling, H. [Institut fuer Chemie, TU Berlin, Strasse des 17. Juni 135, D-10623 Berlin (Germany); Wessel, C.; Wolff, H. [Institut fuer Anorganische Chemie, RWTH Aachen, Landoltweg 1, D-52056 Aachen (Germany); Boerger, A. [Institut fuer Physikalische und Theoretische Chemie, TU Braunschweig, Hans-Sommer-Str. 10, D-38106 Braunschweig (Germany); Baehtz, C. [HASYLAB at DESY, Netkestr. 85, D-22603 Hamburg (Germany); Becker, K.-D. [Institut fuer Physikalische und Theoretische Chemie, TU Braunschweig, Hans-Sommer-Str. 10, D-38106 Braunschweig (Germany); Dronskowski, R. [Institut fuer Anorganische Chemie, RWTH Aachen, Landoltweg 1, D-52056 Aachen (Germany); Lerch, M., E-mail: lerch@chem.tu-berlin.d [Institut fuer Chemie, TU Berlin, Strasse des 17. Juni 135, D-10623 Berlin (Germany)

    2010-09-15T23:59:59.000Z

    The aim of our study was to modify the basis compound ss-TaON, which crystallizes in the monoclinic baddeleyite-type, by incorporation of appropriate dopant ions, in order to obtain anion-deficient cubic fluorite-type phases, which are of interest as solids with mobile nitrogen ions. For this purpose, scandium-doped tantalum oxide nitrides were prepared by ammonolysis of amorphous oxide precursors. An unexpected variety of phases with different structural features was observed: bixbyite-type phases of general composition Sc{sub x}Ta{sub 1-x}(O,N){sub y} with 0.33{<=}x{<=}1 and 1.7{<=}y{<=}1.9, yellow colored metastable anatase-type phases such as Sc{sub 0.1}Ta{sub 0.9}O{sub 1.2}N{sub 0.8} or Sc{sub 0.15}Ta{sub 0.85}O{sub 1.3}N{sub 0.7} and, additionally, anosovite-type phases Sc{sub x}Ta{sub 3-x}O{sub 2x}N{sub 5-2x} with 0{<=}x{<=}1.05. Selected phases were investigated by UV/vis spectroscopy. Anatase- and anosovite-type compounds show brilliant colors. In the anatase-type phase, a possible anion ordering was examined by theoretical methods. Additionally, energy calculations on phase stability were performed for Sc{sub x}Ta{sub 1-x}O{sub 1+2x}N{sub 1-2x} in the baddeleyite, rutile, and anatase structure types with varying amounts of dopants. - Graphical abstract: New anatase- and bixbyite-type phases obtained as single-phase samples in the system Sc-Ta-O-N.

  11. Shell-Based Support Structures for Nb3Sn Accelerator Quadrupole Magnets

    E-Print Network [OSTI]

    Ferracin, Paolo

    2010-01-01T23:59:59.000Z

    similarly to the outer shell, they significantly increasedof Technology Quadrupole Shell (TQS) Magnet Models forSHELL-BASED SUPPORT STRUCTURES FOR NB 3 SN ACCELERATOR

  12. Precessional magnetization induced spin current from CoFeB into Ta

    SciTech Connect (OSTI)

    Jamali, Mahdi; Klemm, Angeline; Wang, Jian-Ping, E-mail: jpwang@umn.edu [Department of Electrical and Computer Engineering, University of Minnesota, 4-174 200 Union Street SE, Minneapolis, Minnesota 55455 (United States)] [Department of Electrical and Computer Engineering, University of Minnesota, 4-174 200 Union Street SE, Minneapolis, Minnesota 55455 (United States)

    2013-12-16T23:59:59.000Z

    The spin dynamics at the interface between the CoFeB and Ta layer has been studied using spin pumping and spin wave characterizations. The spin pumping driven by the ferromagnetic resonance in the CoFeB layer injects a spin current into Ta layer which results in an electromotive force across the Ta layer due to the inverse spin Hall effect. Upon changing the polarity of the bias magnetic field, the polarity of the output voltage inverts and the output voltage increases linearly in respect to the microwave signal power which are consistent with the spin pumping characteristics. The effect of the in-plane magnetization angle on the output voltage has been studied. Furthermore, it is found that the frequency spectrum of the spin Hall voltage is modified by the annealing temperature and the full width at half maximum of the spin pumping increases by more than 40% with the increase of the annealing temperature from 200?°C to 300?°C. The spin Hall angle at the Ta-CoFeB interface is determined to be 0.014, and the damping constant of the CoFeB increases from 0.006 in pure CoFeB to 0.015 in Ta/CoFeB film.

  13. Design and evaluation of a novel breast cancer detection system combining both thermoacoustic ,,TA... and photoacoustic ,,PA... tomography

    E-Print Network [OSTI]

    Wang, Lihong

    Design and evaluation of a novel breast cancer detection system combining both thermoacoustic ,,TA thermoacoustic and photoacoustic techniques to achieve dual contrast microwave and light absorption imaging

  14. Role of spin mixing conductance in spin pumping: Enhancement of spin pumping efficiency in Ta/Cu/Py structures

    SciTech Connect (OSTI)

    Deorani, Praveen; Yang, Hyunsoo, E-mail: eleyang@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore (Singapore)] [Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore (Singapore)

    2013-12-02T23:59:59.000Z

    From spin pumping measurements in Ta/Py devices for different thicknesses of Ta, we determine the spin Hall angle to be 0.021–0.033 and spin diffusion length to be 8?nm in Ta. We have also studied the effect of changing the properties of non-magnet/ferromagnet interface by adding a Cu interlayer. The experimental results show that the effective spin mixing conductance increases in the presence of Cu interlayer for Ta/Cu/Py devices whereas it decreases in Pt/Cu/Py devices. Our findings allow the tunability of the spin pumping efficiency by adding a thin interlayer at the non-magnet/ferromagnet interface.

  15. The effect of Ta interface on the crystallization of amorphous phase change material thin films

    SciTech Connect (OSTI)

    Ghezzi, G. E. [CEA-LETI, MINATEC campus, 17 rue des Martyrs, F 38054 Grenoble (France); LMGP, CNRS Grenoble-INP, MINATEC, 3 parvis Louis Néel, F 38016 Grenoble (France); Noé, P., E-mail: pierre.noe@cea.fr; Marra, M.; Sabbione, C.; Fillot, F.; Bernier, N.; Ferrand, J.; Maîtrejean, S. [CEA-LETI, MINATEC campus, 17 rue des Martyrs, F 38054 Grenoble (France); Hippert, F. [LMGP, CNRS Grenoble-INP, MINATEC, 3 parvis Louis Néel, F 38016 Grenoble (France); LNCMI (CNRS, UJF, UPS, INSA), 25 rue des Martyrs, F 38042 Grenoble Cedex 9 (France)

    2014-06-02T23:59:59.000Z

    The crystallization of amorphous GeTe and Ge{sub 2}Sb{sub 2}Te{sub 5} phase change material films, with thickness between 10 and 100?nm, sandwiched between either Ta or SiO{sub 2} layers, was investigated by optical reflectivity. Ta cladding layers were found to increase the crystallization temperature, even for films as thick as 100?nm. X-Ray diffraction investigations of crystallized GeTe films showed a very weak texture in Ta cladded films, in contrast with the strong texture observed for SiO{sub 2} cladding layers. This study shows that crystallization mechanism of phase change materials can be highly impacted by interface effects, even for relatively thick films.

  16. Functional and operational requirements for TA-18 relocation to the NTS/DAF Site.

    SciTech Connect (OSTI)

    Malenfant, R. E. (Richard E.); Bedsun, D. A. (David A.); Paternoster, Richard R.,

    2002-01-01T23:59:59.000Z

    Technical Area 18 (TA-18), or Pajarito Site, of the Los Alamos National Laboratory has been operational as a nuclear facility since 1945. The original complement of a dozen part-time researchers with a single mission in one building at the end of a dirt road has evolved to a complex, multimission facility with a staff of 125 occupying 25 major buildings adjacent to a heavily traveled road with public access. In the year 2000, the Secretary of Energy determined that the mission of TA-18 was essential to support national security, but that consideration had to be given to improving safety and physical security. It is presently proposed to relocate most of the TA-18 operations to the Device Assembly Facility (DAF) at the Nevada Test Site (NTS). The purpose of this paper is to identify the functional and operational requirements and to demonstrate how they can be met at the DAF.

  17. Development of Superconducting Materials for Use in Magnet Applications: Nb3Sn Flux Pinning and Bi-2212 Magnetic Texturing 

    E-Print Network [OSTI]

    Rahmani, David G.

    2010-07-14T23:59:59.000Z

    as round wires are presented and discussed. Processes were developed to increase flux pinning in Nb3Sn by utilizing powder metallurgy techniques to introduce a heterogeneously homogenous distribution of nanoscale inclusions of candidate materials in Nb rod...

  18. Development of Superconducting Materials for Use in Magnet Applications: Nb3Sn Flux Pinning and Bi-2212 Magnetic Texturing

    E-Print Network [OSTI]

    Rahmani, David G.

    2010-07-14T23:59:59.000Z

    as round wires are presented and discussed. Processes were developed to increase flux pinning in Nb3Sn by utilizing powder metallurgy techniques to introduce a heterogeneously homogenous distribution of nanoscale inclusions of candidate materials in Nb rod...

  19. OXYDATION ET PHNOMNE DE PESTE DE L'ALUMINIURE DE NIOBIUM NbAl3

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    535 OXYDATION ET PHÉNOMČNE DE PESTE DE L'ALUMINIURE DE NIOBIUM NbAl3 G. RAISSON, A. VIGNES Ecole niobium NbAl3 est le constituant principal des couches protec- trices ŕ base d'aluminiures des alliages de niobium. L'oxydation de ce composé a été étudiée dans le domaine de températures 600-1 400 °C. Au

  20. Microstructure development in Nb3Sn(Ti) internal tin superconducting wire

    E-Print Network [OSTI]

    Elliott, James

    Microstructure development in Nb3Sn(Ti) internal tin superconducting wire I. Pong Ć S. C. Hopkins Ć have studied the phase formation sequences in a Nb3Sn `internal tin' process superconductor. Heat treatments were performed to convert the starting materials of tin, Ti­Sn, copper and niobium, to bronze

  1. NbTiN Based SIS Multilayer Structures for SRF Applications

    SciTech Connect (OSTI)

    Valente, Anne-marie; Eremeev, Grigory; Phillips, H.; Reece, Charles; Spradlin, Joshua; Yang, Qiguang; Lukaszew, Rosa

    2013-09-01T23:59:59.000Z

    For the past three decades, bulk niobium has been the material of choice for SRF cavities applications. RF cavity performance is now approaching the theoretical limit for bulk niobium. For further improvement of RF cavity performance for future accelerator projects, Superconductor ? Insulator - Superconductor (SIS) multilayer structures (as recently proposed by Alex Gurevich) present the theoretical prospect to reach RF performance beyond bulk Nb, using thinly layered higher-Tc superconductors with enhanced Hc1. Jefferson Lab (JLab) is pursuing this approach with the development of NbTiN and AlN based multilayer SIS structures. This paper presents the results on the characteristics of NbTiN films and the first RF measurements on NbTiN-based multilayer structure on thick Nb films.

  2. Thermoelectric Properties of Nb3SbxTe7-x Compounds Sidney Wang, G. Jeff Snyder, and Thierry Caillat

    E-Print Network [OSTI]

    Thermoelectric Properties of Nb3SbxTe7-x Compounds Sidney Wang, G. Jeff Snyder, and Thierry Caillat antimony telluride, Nb3SbxTe7-x, was synthesized and tested for thermoelectric properties in the Thermoelectrics group at the Jet Propulsion Laboratory. The forty atoms per unit cell of Nb3Sb2Te5 and its varied

  3. FEM Analysis of Nb-Sn Rutherford-type Cables

    SciTech Connect (OSTI)

    Barzi, Emanuela; Gallo, Giuseppe; Neri, Paolo; /Fermilab

    2011-01-01T23:59:59.000Z

    An important part of superconducting accelerator magnet work is the conductor. To produce magnetic fields larger than 10 T, brittle conductors are typically used. For instance, for Nb{sub 3}Sn the original round wire, in the form of a composite of Copper, Niobium and Tin, is assembled into a so-called Rutherford-type cable, which is used to wind the magnet. The magnet is then subjected to a high temperature heat treatment to produce the chemical reactions that make the material superconducting. At this stage the superconductor is brittle and its superconducting properties sensitive to strain. This work is based on the development of a 2D finite element model, which simulates the mechanical behavior of Rutherford-type cable before heat treatment. The model was applied to a number of different cable architectures. To validate a critical criterion adopted into the single Nb-Sn wire analysis, the results of the model were compared with those measured experimentally on cable cross sections.

  4. TA-55 Final Safety Analysis Report Comparison Document and DOE Safety Evaluation Report Requirements

    SciTech Connect (OSTI)

    Alan Bond

    2001-04-01T23:59:59.000Z

    This document provides an overview of changes to the currently approved TA-55 Final Safety Analysis Report (FSAR) that are included in the upgraded FSAR. The DOE Safety Evaluation Report (SER) requirements that are incorporated into the upgraded FSAR are briefly discussed to provide the starting point in the FSAR with respect to the SER requirements.

  5. High-pressure shock behavior of WC and Ta2O5 powders.

    SciTech Connect (OSTI)

    Knudson, Marcus D. (Sandia National Laboratories, Albuquerque, NM); Reinhart, William Dodd (Sandia National Laboratories, Albuquerque, NM); Vogler, Tracy John; Root, Seth (Sandia National Laboratories, Albuquerque, NM)

    2011-10-01T23:59:59.000Z

    Planar shock experiments were conducted on granular tungsten carbide (WC) and tantalum oxide (Ta{sub 2}O{sub 5}) using the Z machine and a 2-stage gas gun. Additional shock experiments were also conducted on a nearly fully dense form of Ta{sub 2}O{sub 5}. The experiments on WC yield some of the highest pressure results for granular materials obtained to date. Because of the high distention of Ta{sub 2}O{sub 5}, the pressures obtained were significantly lower, but the very high temperatures generated led to large contributions of thermal energy to the material response. These experiments demonstrate that the Z machine can be used to obtain accurate shock data on granular materials. The data on Ta{sub 2}O{sub 5} were utilized in making improvements to the P-{lambda} model for high pressures; the model is found to capture the results not only of the Z and gas gun experiments but also those from laser experiments on low density aerogels. The results are also used to illustrate an approach for generating an equation of state using only the limited data coming from nanoindentation. Although the EOS generated in this manner is rather simplistic, for this material it gives reasonably good results.

  6. taBLe of Contents 2 Find a Job or Internship

    E-Print Network [OSTI]

    Hone, James

    spring 2013 program of events #12;taBLe of Contents 2 Find a Job or Internship 4 All Students, 2013 Deadline to accept internship offers from previous summer internships March 15, 2013 Deadline to accept internship offers received during Spring Semester OCR Employer Info Sessions Employer Info

  7. ACTIVITY, MOVEMENTS, AND FEEDING BEHAVIOR OF THE CUNNER, TA UTOGOLABRUS ADSPERSUS, AND COMPARISON OF

    E-Print Network [OSTI]

    ACTIVITY, MOVEMENTS, AND FEEDING BEHAVIOR OF THE CUNNER, TA UTOGOLABRUS ADSPERSUS, AND COMPARISON providing the nighttime shelter. The fish overwinter within their home territory in a torpid, nonfeeding of young tautog of similar size. 'This work was supported in part by a grant from the U.S. Atomic Energy

  8. GRAIN BOUNDARY EVOLUTION: NEW PERSPECTIVES M. EMELIANENKO, D. GOLOVATY, D. KINDERLEHRER, AND S. TA'ASAN

    E-Print Network [OSTI]

    that they are robust but they are not strongly related to energetics. Recent work has provided us with a new statisticGRAIN BOUNDARY EVOLUTION: NEW PERSPECTIVES M. EMELIANENKO, D. GOLOVATY, D. KINDERLEHRER, AND S. TA boundaries. The energetics and connectivity of the net- work of boundaries are implicated in many properties

  9. CRAD, Criticality Safety- Los Alamos National Laboratory TA 55 SST Facility

    Broader source: Energy.gov [DOE]

    A section of Appendix C to DOE G 226.1-2 "Federal Line Management Oversight of Department of Energy Nuclear Facilities." Consists of Criteria Review and Approach Documents (CRADs) used for an assessment of the Criticality Safety program at the Los Alamos National Laboratory, TA 55 SST Facility.

  10. CRAD, Radiological Controls- Los Alamos National Laboratory TA 55 SST Facility

    Broader source: Energy.gov [DOE]

    A section of Appendix C to DOE G 226.1-2 "Federal Line Management Oversight of Department of Energy Nuclear Facilities." Consists of Criteria Review and Approach Documents (CRADs) used for an assessment of the Radiation Protection Program at the Los Alamos National Laboratory TA 55 SST Facility.

  11. CRAD, Occupational Safety & Health- Los Alamos National Laboratory TA 55 SST Facility

    Broader source: Energy.gov [DOE]

    A section of Appendix C to DOE G 226.1-2 "Federal Line Management Oversight of Department of Energy Nuclear Facilities." Consists of Criteria Review and Approach Documents (CRADs) used for an assessment of the Industrial Hygiene program at the Los Alamos National Laboratory TA 55 SST Facility.

  12. Dig-ta Video, Learn-ng Styes, and Student Understanding of Kinematics Graphs

    E-Print Network [OSTI]

    Zollman, Dean

    Dig-ta Video, Learn-ng Styes, and Student Understanding of Kinematics Graphs Teresa Larkin Video, Learning Styles, and Student Understanding of Kinematics Graphs Introduction Student learning interactive digital video as well preferences and student understanding and their ability to interpret motion

  13. TA Orientation 2004 Activity 5 (2 points). Teaching Discussion Sessions at UMn

    E-Print Network [OSTI]

    Minnesota, University of

    questions and comments (2) The Mentor TA will lead a class discussion about your questions. Write important & Useful Information (one per person) OR of useful information to put on board Photocopies of Answer Sheet) passing out Problem & Useful Information and Answer Sheet. · Students sitting and listening · Students

  14. Phonon and thermal properties of exfoliated TaSe2 thin films T. R. Pope,2

    E-Print Network [OSTI]

    films exfoliated from TaSe2 and other metal dichalcogenides, as well as for evaluating self-heating-Device Laboratory, Department of Electrical Engineering, Bourns College of Engineering, University of California its bulk value of $16 W/mK to $9 W/mK in 45-nm thick films. The measurement of electrical resistivity

  15. Mesoscale Simulation of Grain David Kinderlehrer, Jeehyun Lee, Irene Livshits and Shlomo Ta'asan

    E-Print Network [OSTI]

    Mesoscale Simulation of Grain Growth David Kinderlehrer, Jeehyun Lee, Irene Livshits and Shlomo Ta'asan WILEY-VCH Verlag Berlin GmbH September 4, 2003 #12;2 0.1 Introduction The mesoscale simulation of grain of the statistics it provides, we are led to the companion issue of coarse graining in mesoscale simulations. We

  16. Applied Reactor Physics TA RG E T AU D I E N C E

    E-Print Network [OSTI]

    Meunier, Michel

    Applied Reactor Physics TA RG E T AU D I E N C E Applied Reactor Physics is designed for an audi- ence at the graduate level, without preliminary knowledge of reactor physics. A number of excel- lent courses. Most production codes in reactor physics are accompanied with rather complete theory guides

  17. CLOUD GAMING ONWARD: RESEARCH OPPORTUNITIES AND OUTLOOK Kuan-Ta Chen1

    E-Print Network [OSTI]

    Chen, Sheng-Wei

    CLOUD GAMING ONWARD: RESEARCH OPPORTUNITIES AND OUTLOOK Kuan-Ta Chen1 , Chun-Ying Huang2 ABSTRACT Cloud gaming has become increasingly more popular in the academia and the industry, evident by the large numbers of related research papers and startup companies. Some pub- lic cloud gaming services have

  18. Nanoclustering of hydrogen in ion-implanted and plasma-grown amorphous silicon Debye Institute, Utrecht University, P.O. Box 80000, 3508 TA Utrecht, The Netherlands

    E-Print Network [OSTI]

    Polman, Albert

    Institute, Utrecht University, P.O. Box 80000, 3508 TA Utrecht, The Netherlands D. L. Williamson Department. van der Weg Debye Institute, Utrecht University, P.O. Box 80000, 3508 TA Utrecht, The Netherlands A

  19. Fergusonite-type CeNbO{sub 4+?}: Single crystal growth, symmetry revision and conductivity

    SciTech Connect (OSTI)

    Bayliss, Ryan D. [Department of Materials, Imperial College London, Prince Consort Road, London, SW7 2BP (United Kingdom); Pramana, Stevin S.; An, Tao; Wei, Fengxia; Kloc, Christian L. [School of Materials Science and Engineering, 50 Nanyang Avenue, Nanyang Technological University, 639798 (Singapore); White, Andrew J.P. [Chemical Crystallography Laboratory, Department of Chemistry, Imperial College London, Exhibition Road, London, SW7 2AZ (United Kingdom); Skinner, Stephen J. [Department of Materials, Imperial College London, Prince Consort Road, London, SW7 2BP (United Kingdom); White, Timothy J. [School of Materials Science and Engineering, 50 Nanyang Avenue, Nanyang Technological University, 639798 (Singapore); Baikie, Tom, E-mail: tbaikie@ntu.edu.sg [School of Materials Science and Engineering, 50 Nanyang Avenue, Nanyang Technological University, 639798 (Singapore)

    2013-08-15T23:59:59.000Z

    Large fergusonite-type (ABO{sub 4}, A=Ce, B=Nb) oxide crystals, a prototype electrolyte composition for solid oxide fuel cells (SOFC), were prepared for the first time in a floating zone mirror furnace under air or argon atmospheres. While CeNbO{sub 4} grown in air contained CeNbO{sub 4.08} as a minor impurity that compromised structural analysis, the argon atmosphere yielded a single phase crystal of monoclinic CeNbO{sub 4}, as confirmed by selected area electron diffraction, powder and single crystal X-ray diffraction. The structure was determined in the standard space group setting C12/c1 (No. 15), rather than the commonly adopted I12/a1. AC impedance spectroscopy conducted under argon found that stoichiometric CeNbO{sub 4} single crystals showed lower conductivity compared to CeNbO{sub 4+?} confirming interstitial oxygen can penetrate through fergusonite and is responsible for the higher conductivity associated with these oxides. - Graphical abstract: Large fergusonite-type CeNbO{sub 4} crystals were prepared for the first time in a floating zone mirror furnace. Crystal growth in an argon atmosphere yielded a single phase monoclinic CeNbO4, as confirmed by selected area electron diffraction, powder and single crystal X-ray diffraction. The structure was determined in the standard space group setting C12/c1 (No. 15), rather than the commonly adopted I12/a1. AC impedance spectroscopy found CeNbO{sub 4} single crystals showed lower conductivity compared to CeNbO{sub 4+?} confirming interstitial oxygen can penetrate through fergusonite and is responsible for the higher conductivity associated with these oxides. Highlights: • Preparation of single crystals of CeNbO{sub 4} using a floating zone mirror furnace. • Correction to the crystal symmetry of the monoclinic form of CeNbO{sub 4}. • Report the conductivity of a single crystal of CeNbO{sub 4}.

  20. Landslides and other mass movements near TA-33, northern White Rock Canyon, New Mexico. Final report

    SciTech Connect (OSTI)

    Dethier, D.P.

    1993-09-01T23:59:59.000Z

    Massive slump complexes and at least two rock avalanches flank the eastern rim of the Pajarito Plateau along northern White Rock Canyon, north of TA-33. Landslides failed along mechanically weak rocks in the Santa Fe Group, within the Puye Formation, or in Pliocene alluvial and lacustrine units. The landslides are mainly of early or middle Pleistocene age. The toe area of at least,one slump complex has been active in the late Pleistocene, damming White Rock Canyon near the mouth of Water Canyon. Lacustrine sediment that filled this lake, or series of lakes, to an elevation of at least 1710 m is preserved at a number of upstream sites, including a deposit near the Buckman townsite that exposes 30 m of lacustrine sediment. Charcoal collected at several sites has been submitted for {sup 14}C dating. Landslides, however, probably do not represent a significant short-term threat to the material disposal areas at TA-33. Bedrock that lies beneath the TA-33 mesa is relatively stable, the mesa shows no signs of incipient failure, and past periods of slide activity were responses to rapid downcutting of the Rio Grande and climate change, probably over periods of several decades, at least. Rockfall and headward erosion of gullies do not represent significant decadal hazards on canyon rims near TA-33. Gully migration near MDA-K is a potential threat, but the gullies were not examined in detail. A system of north-trending faults, at least one of which displays Pleistocene activity, bisects the TA-33 mesa. If these faults are capable of producing significant seismic shaking, generalizations about landslide and rockfall hazards must be reevaluated.

  1. The Use of TaBoRR as a Heavy Oil Upgrader

    SciTech Connect (OSTI)

    Lee Brecher; Charles Mones

    2009-02-05T23:59:59.000Z

    Preliminary testing has shown that Western Research Institute's (WRI) Tank Bottom Recovery and Remediation (TaBoRR{reg_sign}) technology shows promise for heavy oil upgrading. Approximately 70 to 75 wt% of a Canadian Cold Lake bitumen feed was converted to a partially upgraded overhead product that could be transported directly by pipeline or blended with the parent bitumen to produce transportable crude. TaBoRR{reg_sign} was originally developed to remediate tank bottom wastes by producing a distillate product and solid waste. TaBoRR{reg_sign}'s processing steps include breaking a water-oil emulsion, recovering a light hydrocarbon fraction by distillation in a stripper unit, and pyrolyzing the residua reducing it to additional overhead and a benign coke for disposal. Cold Lake bitumen was tested in WRI's bench-scale equipment to evaluate the potential use of TaBoRR{reg_sign} technology for heavy oil upgrading to produce a stable, partially (or fully) upgraded product that will allow diluent-reduced or diluent-free transportation of bitumen or ultra-heavy crudes to market. Runs were conducted at temperatures of low, intermediate and high severity in the stripper to produce stripper overhead and bottoms. The bottoms from each of these runs were processed further in a 6-inch screw pyrolyzer to produce pyrolyzer overhead for blending with the corresponding stripper overheads. Proceeding in this fashion yielded three partially upgraded crudes. The products from TaBoRR{reg_sign} processing, the parent bitumen, and bitumen blends were subjected to stability and compatibility testing at the National Centre for Upgrading Technology (NCUT). Chemical analyses of the overhead product blends have met pipeline specifications for viscosity and density; however the bromine number does not, which might indicate the need for mild hydrotreating. Storage stability tests showed the blends to be stable. The blends were also soluble and compatible with most other Alberta crudes.

  2. Seeking the optimal LaTaO{sub 4}:Eu phosphor

    SciTech Connect (OSTI)

    Bleier, Grant C. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185 (United States); Nyman, May, E-mail: mdnyman@sandia.gov [Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185 (United States); Rohwer, Lauren E.S.; Rodriguez, Mark A. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185 (United States)

    2011-12-15T23:59:59.000Z

    Lanthanum orthotantalate, LaTaO{sub 4}, is an excellent host lattice for rare-earth luminescent ions such as Eu{sup 3+} for red emission. However, there are multiple RETaO{sub 4} (RE=rare earth) polymorphs, and the stability of these is controlled predominantly by the RE-radius. Thus it is difficult to obtain a pure phase of LaTaO{sub 4}:Eu as Eu concentration and consequently the RE radius is varied. We recently reported a 'soft-chemical' route that allows crystallization of pure-phase LaTaO{sub 4}:Eu at temperatures as low as 800 Degree-Sign C. In the current report, we investigate polymorph evolution and Eu emission as a function of Eu concentration and annealing temperature. We obtain a maximum quantum yield (QY) of 83% at the highest Eu substitution (25%) for which the low temperature orthorhombic (Pbca) polymorph is stable. Therefore, QY is not limited necessarily by concentration quenching; rather it is limited by polymorph stability as the RE-radius decreases with increasing Eu substitution. - Graphical Abstract: Eu-substituted lanthanum orthotantalates, LaTaO{sub 4}:Eu, are excellent red phosphors. They exhibit up to 83% quantum-yield emission under blue light excitation, optimized through both 'soft chemical processing' and polymorph purity. Highlights: Black-Right-Pointing-Pointer LaTaO{sub 4}:Eu phosphors were synthesized via 'soft-chemical' and solid-state routes. Black-Right-Pointing-Pointer Quantum-yield of Eu emission depends on host polymorph, which changes with La:Eu ratio. Black-Right-Pointing-Pointer Polymorph with optimal Eu-emission is only obtained by 'soft-chemistry'.

  3. Solar Energy Materials & Solar Cells 91 (2007) 17261732 Optical and structural properties of Ta2O5CeO2 thin films

    E-Print Network [OSTI]

    Thirumalai, Devarajan

    Solar Energy Materials & Solar Cells 91 (2007) 1726­1732 Optical and structural properties of Ta2O5

  4. Electron concentration and phase stability in NbCr2-based Laves phase alloys

    SciTech Connect (OSTI)

    Zhu, J.H.; Liaw, P.K. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering; Liu, C.T. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1997-05-12T23:59:59.000Z

    Phase stability in NbCr{sub 2}-based transition-metal Laves phases was studied, based on the data reported for binary X-Cr, Nb-X, and ternary Nb-Cr-X phase diagrams. It was shown that when the atomic size ratios are kept identical, the average electron concentration factor, e/a, is the dominating factor in controlling the phase stability of NbCr{sub 2}-based transition-metal Laves phases. The e/a ratios for different Laves polytypes were determined as followed: with e/a < 5.76, the C15 structure is stabilized; at an e/a range of 5.88--7.53, the C14 structure is stabilized; with e/a > 7.65, the C15 structure is stabilized again. A further increase in the electron concentration factor (e/a > 8) leads to the disordering of the alloy. The electron concentration effect on the phase stability of Mg-based Laves phases and transition-metal A{sub 3}B intermetallic compounds is also reviewed and compared with the present observations in transition-metal Laves phases. In order to verify the e/a/phase stability relationship experimentally, additions of Cu (with e/a = 11) were selected to replace Cr in the NbCr{sub 2} Laves phase. Experimental results for the ternary Nb-Cr-Cu system are reported and discussed in terms of the correlation between the e/a ratio and phase stability in NbCr{sub 2}-based Laves phases. A new phase was found, which has an average composition of Nb-47Cr-3Cu. Within the solubility limit, the electron concentration and phase stability relationship is obeyed in the Nb-Cr-Cu system.

  5. Developmentof the 15 T Nb3Sn dipole HD2

    SciTech Connect (OSTI)

    Caspi, S.; Cheng, D.W.; Dietderich, D.R.; Hafalia, A.R.; Hannaford, C.R.; Higley, H.; Lietzke, A.F.; Lizarazo, J.; McInturff, A.D.; Sabbi, G.; Ferracin, P.

    2008-06-01T23:59:59.000Z

    The Superconducting Magnet Program at Lawrence Berkeley National Laboratory (LBNL) is continuing the development of HD2, a 1 m long Nb{sub 3}Sn dipole generating a dipole field of 15 T in a 36 mm clear bore. With tilted (flared) ends to avoid obstructing the beam path, HD2 represents a step towards the development of cost effective accelerator quality magnets. The design has been optimized to minimize geometric harmonics and to address iron saturation and conductor magnetization effects. The support structure is based on an external aluminum shell, pre-tensioned with pressurized bladders and interference keys. Aluminum axial rods and stainless steel end plates provide longitudinal support to the coil ends during magnet excitation. This paper reports on field quality optimization and magnet parameters. The design and fabrication of the coil and structure components, and results from coil winding, reaction, and potting are also presented.

  6. Nb3Sn Quadrupoles Designs For The LHC Upgrades

    SciTech Connect (OSTI)

    Felice, Helene

    2008-05-19T23:59:59.000Z

    In preparation for the LHC luminosity upgrades, high field and large aperture Nb{sub 3}Sn quadrupoles are being studied. This development has to incorporate all the relevant features for an accelerator magnet like alignment and cooling channels. The LARP HQ model is a high field and large bore quadrupole that will meet these requirements. The 2-layer coils are surrounded by a structure based on key and bladder technology with supporting iron yoke and aluminum shell. This structure is aimed at pre-stress control, alignment and field quality. We present here the magnetic and mechanical design of HQ, along with recent progress on the development of the first 1-meter model.

  7. Effect of V and Ta on the precipitation behavior of 12%Cr reduced activation ferrite/martensite steel

    SciTech Connect (OSTI)

    Xiao, Xiang [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Liu, Guoquan, E-mail: g.liu@ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Hu, Benfu; Wang, Jinsan [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Ullah, Asad [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Department of Mathematics, Karakoram International University, Gilgit-Baltistan (Pakistan)

    2013-08-15T23:59:59.000Z

    12%Cr reduced activation ferrite/martensite steels are promising candidate materials for good corrosion and irradiation resistance used for supercritical water-cooled reactor cladding and in-core components. V and Ta are considered to have improved the creep strength of high Cr steels by precipitating as MX phase. In this paper, a series of trial products microalloyed with V and V–Ta are produced, and the microstructure is characterized after quenching at 1050 °C and tempering at 780 °C by using TEM method to investigate the effect of these elements on the precipitation behavior of 12%Cr reduced activation ferrite/martensite steel. The results from both the experimental observations and thermodynamic and kinetic calculations reveal that V and V–Ta can promote the stable MX precipitation instead of M{sub 2}X, thus increasing the volume fraction of M{sub 23}C{sub 6}. Two-phase separation behavior of the (Ta, V)(C, N) carbonitride into a Ta(V)C(N) phase and a V(Ta)N(C) phase in 12Cr3WVTa steel is observed and further discussed. - Highlights: • Microalloyed with V and V-Ta can promote the precipitation of MX instead of M{sub 2}X. • The presence of delta-ferrite in microstructure affects the morphology of MX. • Two-phase separation of MX carbonitride was observed in 12Cr3WVTa steel.

  8. Anti-diabetic and hypolipidemic effects of Sargassum yezoense in db/db mice

    SciTech Connect (OSTI)

    Kim, Su-Nam, E-mail: snkim@kist.re.kr [Natural Medicine Center, KIST Gangneung Institute, Gangneung 210-340 (Korea, Republic of)] [Natural Medicine Center, KIST Gangneung Institute, Gangneung 210-340 (Korea, Republic of); Lee, Woojung [Natural Medicine Center, KIST Gangneung Institute, Gangneung 210-340 (Korea, Republic of)] [Natural Medicine Center, KIST Gangneung Institute, Gangneung 210-340 (Korea, Republic of); Bae, Gyu-Un [College of Pharmacy, Sookmyung Women's University, Seoul 140-742 (Korea, Republic of) [College of Pharmacy, Sookmyung Women's University, Seoul 140-742 (Korea, Republic of); Research Center for Cell Fate Control, Sookmyung Women's University, Seoul 140-742 (Korea, Republic of); Kim, Yong Kee, E-mail: yksnbk@sookmyung.ac.kr [College of Pharmacy, Sookmyung Women's University, Seoul 140-742 (Korea, Republic of)

    2012-08-10T23:59:59.000Z

    Highlights: Black-Right-Pointing-Pointer Sargassum yezoense (SY) treatment improved glucose and lipid impairment in vivo. Black-Right-Pointing-Pointer This pharmacological action is associated with PPAR{alpha}/{gamma} dual activation. Black-Right-Pointing-Pointer It decreases the expression of G6Pase for gluconeogenesis in liver. Black-Right-Pointing-Pointer It increases the expression of UCP3 for lipid metabolism in adipose tissue. Black-Right-Pointing-Pointer There are no significant side effects such as body weight gain and hepatomegaly. -- Abstract: Peroxisome proliferator-activated receptors (PPARs) have been considered to be desirable targets for metabolic syndrome, even though their specific agonists have several side effects including body weight gain, edema and tissue failure. Previously, we have reported in vitro effects of Sargassum yezoense (SY) and its ingredients, sargaquinoic acid (SQA) and sargahydroquinoic acid (SHQA), on PPAR{alpha}/{gamma} dual transcriptional activation. In this study, we describe in vivo pharmacological property of SY on metabolic disorders. SY treatment significantly improved glucose and lipid impairment in db/db mice model. More importantly, there are no significant side effects such as body weight gain and hepatomegaly in SY-treated animals, indicating little side effects of SY in liver and lipid metabolism. In addition, SY led to a decrease in the expression of G6Pase for gluconeogenesis in liver responsible for lowering blood glucose level and an increase in the expression of UCP3 in adipose tissue for the reduction of total and LDL-cholesterol level. Altogether, our data suggest that SY would be a potential therapeutic agent against type 2 diabetes and related metabolic disorders by ameliorating the glucose and lipid metabolism.

  9. GhostDB: Hiding Data from Prying Eyes Christophe Salperwyck*

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    one direction: from public to private. This demonstration shows GhostDB's query processing in action Imagine that you have been entrusted with private data, such as corporate product information, sensitive queries whose result will combine private and public data, but private data must not be revealed, say

  10. Metallic to hopping conduction transition in Ta{sub 2}O{sub 5?x}/TaO{sub y} resistive switching device

    SciTech Connect (OSTI)

    Zhang, Ye; Deng, Ning; Yu, Zhiping; Zhang, Jinyu [Institute of Microelectronics, Tsinghua University, Beijing 100084 (China); Wu, Huaqiang, E-mail: wuhq@tsinghua.edu.cn; Qian, He [Institute of Microelectronics, Tsinghua University, Beijing 100084 (China); Tsinghua National Laboratory for Information Science and Technology (TNList), Beijing 100084 (China)

    2014-08-11T23:59:59.000Z

    In this Letter, a comprehensive analysis of how the metallic behavior transition to hopping was presented by studying the transport mechanisms of low resistance states (LRS) in Ta{sub 2}O{sub 5?x}/TaO{sub y} resistive switching devices at very low temperatures. Three types of conduction behaviors were reported through temperature-dependent measurements ranging from 5?K to 250?K. Memory cells at low LRS show metallic behavior due to the formation of metallic filament. The temperature dependence of resistance at medium LRS exhibits an interesting phenomenon that a positive temperature coefficient transfers into a negative one at temperature of 20?K. Detailed analysis reveals that this phenomenon is caused by the coexistence of extended and localized states, with metallic conduction at higher temperatures and variable-range hopping at lower temperatures. Carrier transport at high LRS is dominated by electrons hopping conduction with nearest-neighboring hopping conduction changing into variable-range hopping as temperature decreases.

  11. Development of Nb{sub 3}Sn Cavity Vapor Diffusion Deposition System

    SciTech Connect (OSTI)

    Eremeev, Grigory V.; Macha, Kurt M.; Clemens, William A.; Park, HyeKyoung; Williams, R. Scott

    2014-02-01T23:59:59.000Z

    Nb{sub 3}Sn is a BCS superconductors with the superconducting critical temperature higher than that of niobium, so theoretically it surpasses the limitations of niobium in RF fields. The feasibility of technology has been demonstrated at 1.5 GHz with Nb{sub 3}Sn vapor deposition technique at Wuppertal University. The benefit at these frequencies is more pronounced at 4.2 K, where Nb{sub 3}Sn coated cavities show RF resistances an order of magnitude lower than that of niobium. At Jefferson Lab we started the development of Nb{sub 3}Sn vapor diffusion deposition system within an R\\&D development program towards compact light sources. Here we present the current progress of the system development.

  12. Simulations of Collision Cascades in Cu–Nb Layered Composites Using an EAM Interatomic Potential

    E-Print Network [OSTI]

    Demkowicz, Michael J.

    The embedded atom method (EAM) is used to construct an interatomic potential for modelling interfaces in Cu–Nb nanocomposites. Implementation of the Ziegler–Biersack–Littmark (ZBL) model for short-range interatomic ...

  13. HD1: Design and Fabrication of a 16 Tesla Nb3Sn Dipole Magnet

    E-Print Network [OSTI]

    Hafalia, A.R.

    2011-01-01T23:59:59.000Z

    and Fabrication of a 16 Tesla Nb 3 Sn Dipole Magnet A .R.ge nerating fields above 16 Tesla in practical acceleratordesign fields above 10 Tesla. In a series of magnet tests,

  14. Targets for R&D on Nb$_3$Sn conductor for High Energy Physics

    E-Print Network [OSTI]

    Ballarino, A

    2015-01-01T23:59:59.000Z

    High Energy Physics has been consistently pushing the performance of technical superconductors, for the benefit of high field magnet technology. So far the workhorse for particle accelerators has been Nb-Ti, but the practical performance limit has been attained with the LHC. Calls for higher beam luminosity (e.g. HL-LHC), and higher beam energy (e.g. FCC), demand a transition from Nb-Ti to Nb3Sn, presently the only practical candidate material offering the required high field performance. This paper provides a summary of desirable properties and performance targets for Nb3Sn to satisfy the challenging magnet specifications for upgrades of existing and future HEP accelerators.

  15. Oxidation Behavior and Chlorination Treatment to Improve Oxidation Resistance of Nb-Mo-Si-B Alloys

    SciTech Connect (OSTI)

    Vikas Behrani

    2004-12-19T23:59:59.000Z

    This thesis is written in an alternate format. The thesis is composed of a general introduction, two original manuscripts, and a general conclusion. References cited within each chapter are given at the end of each chapter. The general introduction starts with the driving force behind this research, and gives an overview of previous work on boron doped molybdenum silicides, Nb/Nb{sub 5}Si{sub 3} composites, boron modified niobium silicides and molybdenum niobium silicides. Chapter 2 focuses on the oxidation behavior of Nb-Mo-Si-B alloys. Chapter 3 contains studies on a novel chlorination technique to improve the oxidation resistance of Nb-Mo-Si-B alloys. Chapter 4 summarizes the important results in this study.

  16. Characterizations of a CERN NbTi Reference Wire at LBNL

    E-Print Network [OSTI]

    Godeke, A.; Dietderich, D.R.; Higley, H.C.; Liggins, N.L.

    2007-01-01T23:59:59.000Z

    et al. , report number LBNL-62392 Characterizations of aNbTi Reference Wire at LBNL ? A. Godeke † D. R. Dietderich,tests – and analysis – between LBNL, BNL and Fermilab within

  17. Morphological stability of Cu-Nb nanocomposites under high-energy collision cascades

    E-Print Network [OSTI]

    Zhang, Liang

    We use molecular dynamics and phase field simulations to demonstrate that Cu-Nb multilayered nanocomposites with individual layer thicknesses above 2–4?nm remain morphologically stable when subjected to 100?keV collision ...

  18. Nb3Sn superconducting magnets for electron cyclotron resonance ion sources

    E-Print Network [OSTI]

    Ferracin, P.

    2011-01-01T23:59:59.000Z

    the design of a N b S n superconducting magnet system for aNbjSn superconducting magnets for electron cyclotron5 C H 1 1 2 3 1 . Nb Sn superconducting magnets for electron

  19. aperture nb3sn racetrack: Topics by E-print Network

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

    D; Velev, G 2013-01-01 5 Fabrication and test results of a high field, Nb3Sn superconducting racetrack dipole magnet University of California eScholarship Repository Summary:...

  20. Text classification Naive Bayes NB theory Evaluation of TC Web Search and Text Mining

    E-Print Network [OSTI]

    Gray, Alexander

    Bayes NB theory Evaluation of TC Take-away today Text classification: definition & relevance theory Evaluation of TC Take-away today Text classification: definition & relevance to information: definition & relevance to information retrieval Naive Bayes: simple baseline text classifier Theory

  1. Feasibility study of Nb3Al Rutherford cable for high field accelerator magnet application

    SciTech Connect (OSTI)

    Yamada, R.; /Fermilab; Kikuchi, A.; /Tsukuba Magnet Lab.; Ambrosio, G.; Andreev, N.; Barzi, E.; Cooper, C.; Feher, S.; Kashikhin, V.V.; Lamm, M.; Novitski, I.; /Fermilab; Takeuchi, T.; /Tsukuba Magnet Lab.; Tartaglia, M.; Turrioni, D.; /Fermilab; Verweij, A.P.; /CERN; Wake, M.; Willering, G; /Tsukuba Magnet Lab.; Zlobin, A.V.; /Fermilab

    2006-08-01T23:59:59.000Z

    Feasibility study of Cu stabilized Nb{sub 3}Al strand and Rutherford cable for the application to high field accelerator magnets are being done at Fermilab in collaboration with NIMS. The Nb{sub 3}Al strand, which was developed and manufactured at NIMS in Japan, has a non-copper Jc of about 844 A/mm{sup 2} at 15 Tesla at 4.2 K, a copper content of 50%, and filament size of about 50 microns. Rutherford cables with 27 Nb{sub 3}Al strands of 1.03 mm diameter were fabricated and tested. Quench tests on a short cable were done to study its stability with only its self field, utilizing a high current transformer. A pair of 2 meter long Nb{sub 3}Al cables was tested extensively at CERN at 4.3 and 1.9 K up to 11 Tesla including its self field with a high transport current of 20.2 kA. In the low field test we observed instability near splices and in the central region. This is related to the flux-jump like behavior, because of excessive amount of Nb in the Nb{sub 3}Al strand. There is possibility that the Nb in Nb{sub 3}Al can cause instability below 2 Tesla field regions. We need further investigation on this problem. Above 8 Tesla, we observed quenches near the critical surface at fast ramp rate from 1000 to 3000 A/sec, with quench velocity over 100 m/sec. A small racetrack magnet was made using a 14 m of Rutherford cable and successfully tested up to 21.8 kA, corresponding to 8.7 T.

  2. Preliminary results for HIP bonding Ta to W targets for the materials test station

    SciTech Connect (OSTI)

    Dombrowski, David E [Los Alamos National Laboratory; Maloy, Stuart A [Los Alamos National Laboratory

    2009-01-01T23:59:59.000Z

    Tungsten targets for the Materials Test Station (MTS) were clad with thin tantalum cover plates and a tantalum frame using hot isostatic pressing (HIP). A preliminary HIP parameter study showed good bonding and intimate mechanical contact for Ta cover plate thicknesses of 0.25 mm (0.010 inch) and 0.38 mm (0.015 inch). HIP temperatures of full HIP runs were 1500 C (2732 F). HIP pressure was 203 MPa (30 ksi).

  3. The Conversion of CESR to Operate as the Test Accelerator, CesrTA, Part 1: Overview

    E-Print Network [OSTI]

    Billing, M G

    2015-01-01T23:59:59.000Z

    Cornell's electron/positron storage ring (CESR) was modified over a series of accelerator shutdowns beginning in May 2008, which substantially improves its capability for research and development for particle accelerators. CESR's energy span from 1.8 to 5.6 GeV with both electrons and positrons makes it ideal for the study of a wide spectrum of accelerator physics issues and instrumentation related to present light sources and future lepton damping rings. Additionally a number of these are also relevant for the beam physics of proton accelerators. This paper outlines the motivation, design and conversion of CESR to a test accelerator, CesrTA, enhanced to study such subjects as low emittance tuning methods, electron cloud (EC) effects, intra-beam scattering, fast ion instabilities as well as general improvements to beam instrumentation. While the initial studies of CesrTA focussed on questions related to the International Linear Collider (ILC) damping ring design, CesrTA is a very flexible storage ring, capabl...

  4. T-594: IBM solidDB Password Hash Authentication Bypass Vulnerability

    Broader source: Energy.gov [DOE]

    This vulnerability could allow remote attackers to execute arbitrary code on vulnerable installations of IBM solidDB. Authentication is not required to exploit this vulnerability.

  5. Synthesis and crystal structure of Mg{sub 0.5}NbO{sub 2}: An ion-exchange reaction with Mg{sup 2+} between trigonal [NbO{sub 2}]{sup -} layers

    SciTech Connect (OSTI)

    Miura, Akira, E-mail: amiura@yamanashi.ac.jp [Center for Crystal Science and Technology, University of Yamanashi (Japan); Takei, Takahiro; Kumada, Nobuhiro [Center for Crystal Science and Technology, University of Yamanashi (Japan)

    2013-01-15T23:59:59.000Z

    A new layered niobate, Mg{sub 0.5}NbO{sub 2}, was synthesized from LiNbO{sub 2} through a cation-exchange reaction with Mg{sup 2+} at 450-550 Degree-Sign C. This is the first example of a topotactic reaction with an aliovalent cation between trigonal [NbO{sub 2}]{sup -} layers. It is proposed to be isostructural with LiNbO{sub 2} (space group; P6{sub 3}/mmc) with lattice parameters of a=2.9052(6) A, c=10.625(15) A. The lattice parameters and formation energy of Mg{sub 0.5}NbO{sub 2} crystallized in LiNbO{sub 2} form and other layered CaNb{sub 2}O{sub 4} one were calculated by density functional theory. - Graphical abstract: A new layered niobate, Mg{sub 0.5}NbO{sub 2}, was synthesized from LiNbO{sub 2} through a cation-exchange reaction with Mg{sup 2+} at 450-550 Degree-Sign C. It is isostructural with LiNbO{sub 2} with lattice parameters of a=2.9052(6) A, c=10.625(15) A. Mg{sup 2+} are described in spheres located between [NbO{sub 2}]{sup -} trigonal layers and its occupancy is 0.5. Highlights: Black-Right-Pointing-Pointer A new layered niobate, Mg{sub 0.5}NbO{sub 2}, was synthesized from LiNbO{sub 2}. Black-Right-Pointing-Pointer Cation-exchange reaction converted two monovalent Li{sup +} into one divalent Mg{sup 2+} at 450-550 Degree-Sign C. Black-Right-Pointing-Pointer Mg{sub 0.5}NbO{sub 2} was isostructural with LiNbO{sub 2} (space group; P6{sub 3}/mmc). Black-Right-Pointing-Pointer Its lattice parameters were a=2.9052(6) A and c=10.625(15) A. Black-Right-Pointing-Pointer Synthesized Mg{sub 0.5}NbO{sub 2} was calculated to be thermodynamically more favorable.

  6. Development and test of Nb3sn cos-theta coils made of high-jc rrp strands

    SciTech Connect (OSTI)

    Bossert, R.; Ambrosio, G.; Andreev, N.; Barzi, E.; Carcagno, R.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Novitski, I.; Pischalnikov, Yu.; Sylvester, C.; Tartaglia, M.; Turrioni, D.; Yamada, R.; Zlobin, A.V.; /Fermilab

    2005-10-01T23:59:59.000Z

    A series of 1-m long Nb3Sn dipole magnets have been built at Fermilab in an attempt to refine the wind-and-react technology for Nb{sub 3}Sn conductor. Models have been made with MJR and PIT strand with varying degrees of success. Subsequently two new dipole ''mirror'' magnets based on RRP Nb{sub 3}Sn coils were constructed and tested. This paper describes the design, fabrication and test results of those magnets.

  7. Direct measurement of isothermal flow stress of metals at elevated temperatures and high strain rates with application to Ta and Ta-W alloys

    SciTech Connect (OSTI)

    Nemat-Nasser, S.; Isaacs, J.B. [Univ. of California, San Diego, La Jolla, CA (United States)] [Univ. of California, San Diego, La Jolla, CA (United States)

    1997-03-01T23:59:59.000Z

    A technique is developed for measuring the flow stress of metals over a broad range of strains, strain rates, and temperatures, in uniaxial compression. It utilizes a recent, enhanced version of the classical (Kolsky) compression split Hopkinson bar, in which a sample is subjected to a single stress pulse of a predefined profile, and then recovered without being subjected to any other additional loading. For the present application, the UCSD`s split Hopkinson bar is further enhanced by the addition of a new mechanism by means of which the incident and transmission bars of the split Hopkinson construction are moved into a constant-temperature furnace containing the sample, and gently brought into contact with the sample, as the elastic stress pulse reaches and loads the sample. Using several samples of the same material and testing them at the same strain rate and temperature, but different incremental strains, an accurate estimate of the material`s isothermal flow stress can be obtained. Additionally, the modified Hopkinson technique allows the direct measurement of the change in the (high strain-rate) flow stress with a change of the strain rate, while the strain and temperature are kept constant, i.e., the strain rate can be increased or decreased during the high strain-rate test. The technique is applied to obtain both quasi-isothermal and adiabatic flow stresses of tantalum (Ta) and a tantalum-tungsten (Ta-W) alloy at elevated temperatures. These experimental results show the flow stress of these materials to be controlled by a simple long-range plastic-strain-dependent barrier, and a short-range thermally activated Peierls mechanism. For tantalum, a model which fits the experimental data over strains from a few to over 100%, strain rates from quasi-static to 40,000/s, and temperatures from {minus}200 to 1,000 C, is presented and discussed.

  8. March 23, 2008 Databases: Practical DB Design 1 Practical Database Design

    E-Print Network [OSTI]

    Adam, Salah

    approach towards development of information system, called, Information System Development Life Cycle. #12 of Information Systems in Organizations + Why Organizations Use DB Systems + Information System Life Cycle System Life Cycle ... Database DBMS Users Users #12;March 23, 2008 Databases: Practical DB Design 8

  9. CryptDB: A Practical Encrypted Relational DBMS Raluca Ada Popa, Nickolai Zeldovich, and Hari Balakrishnan

    E-Print Network [OSTI]

    Sabatini, David M.

    CryptDB: A Practical Encrypted Relational DBMS Raluca Ada Popa, Nickolai Zeldovich, and Hari Balakrishnan {raluca, nickolai, hari}@csail.mit.edu ABSTRACT CryptDB is a DBMS that provides provable. When individual users or enterprises store their sensitive data in a DBMS today, they must trust

  10. Dumbarton Express Line DB heading to Stanford Oval. AC Transit Line U on Palm Drive.

    E-Print Network [OSTI]

    Dumbarton Express Line DB heading to Stanford Oval. AC Transit Line U on Palm Drive. Photo: Karl Nielsen Photo: Dong Wang Schedules: AC Transit Line U Dumbarton Express Line DB Connections with BART Transit Line U Line U provides express service between Stanford and the Fremont BART station. Other East

  11. Chapter 5: The Single Nucleotide Polymorphism Database (dbSNP) of Nucleotide Sequence Variation

    E-Print Network [OSTI]

    Levin, Judith G.

    Chapter 5: The Single Nucleotide Polymorphism Database (dbSNP) of Nucleotide Sequence Variation, and performance of functional studies. The Single Nucleotide Polymorphism database (dbSNP) is a public single-base nucleotide substitutions (also known as single nucleotide polymorphisms or SNPs), small

  12. The role of Nb in intensity increase of Er ion upconversion luminescence in zirconia

    SciTech Connect (OSTI)

    Smits, K., E-mail: smits@cfi.lu.lv; Sarakovskis, A.; Grigorjeva, L.; Millers, D. [Institute of Solid State Physics, University of Latvia, 8 Kengaraga Str., Riga LV1063 (Latvia); Grabis, J. [Institute of Inorganic Chemistry, Riga Technical University, Salaspils-1 LV2169 (Latvia)

    2014-06-07T23:59:59.000Z

    It is found that Nb co-doping increases the luminescence and upconversion luminescence intensity in rare earth doped zirconia. Er and Yb-doped nanocrystalline samples with or without Nb co-doping were prepared by sol-gel method and thermally annealed to check for the impact of phase transition on luminescence properties. Phase composition and grain sizes were examined by X-ray diffraction; the morphology was checked by scanning- and high-resolution transmission electron microscopes. Both steady-state and time-resolved luminescence were studied. Comparison of samples with different oxygen vacancy concentrations and different Nb concentrations confirmed the known assumption that oxygen vacancies are the main agents for tetragonal or cubic phase stabilization. The oxygen vacancies quench the upconversion luminescence; however, they also prevent agglomeration of rare-earth ions and/or displacement of rare-earth ions to grain surfaces. It is found that co-doping with Nb ions significantly (>20 times) increases upconversion luminescence intensity. Hence, ZrO{sub 2}:Er:Yb:Nb nanocrystals may show promise for upconversion applications.

  13. A simple growth method for Nb?O? films and their optical properties

    SciTech Connect (OSTI)

    Dash, J. K. [Renesselaer Polytechnic Institute, Troy, NY (United States); Kisslinger, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Chen, L. [Renesselaer Polytechnic Institute, Troy, NY (United States); Topka, Michael R. [Renesselaer Polytechnic Institute, Troy, NY (United States); Dinolfo, Peter H. [Renesselaer Polytechnic Institute, Troy, NY (United States); Zhang, L. H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Lu, T. -M. [Renesselaer Polytechnic Institute, Troy, NY (United States); Wang, G. -C. [Renesselaer Polytechnic Institute, Troy, NY (United States)

    2015-01-01T23:59:59.000Z

    A simple method for the synthesis of Nb?O? films of thicknesses ranging from tens to several hundreds of nanometers on amorphous silicon dioxide or quartz substrates is presented. Nb?O? films were formed by annealing the sputter deposited Nb films under an Ar flow and without oxygen plasma in a quartz tube within a furnace at 850 °C. The structural, compositional, optical, and vibrational properties were characterized by grazing incidence X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet visible spectroscopy, and Raman scattering. Each of the Nb?O? films is polycrystalline with an orthorhombic crystal structure. We observed vibrational modes including longitudinal optical, transverse optical, and triply degenerate modes, and measured the indirect optical band gap to be ~3.65 eV. The transmittance spectrum of the ~20 nm thick Nb?O? film shows over 90% transmittance below the band gap energy in the visible wavelength range and decreases to less than 20% in the ultraviolet regime. The optical properties of the films in the UV-vis range show potential applications as UV detectors.

  14. Highly transparent Nb-doped indium oxide electrodes for organic solar cells

    SciTech Connect (OSTI)

    Kim, Jun Ho; Seong, Tae-Yeon [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Na, Seok-In [Professional Graduate School of Flexible and Printable Electronics, Chonbuk National University, 664-14, Deokjin-dong, Jeongju-si, Jellabuk-do 561-756 (Korea, Republic of); Chung, Kwun-Bum [Department of Physics, Dankook University, Mt. 29, Anseo-Dong, Chenan 330-714 (Korea, Republic of); Lee, Hye-Min; Kim, Han-Ki, E-mail: imdlhkkim@khu.ac.kr [Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, 1 Seocheon-dong, Yongin, Gyeonggi-do 446-701 (Korea, Republic of)

    2014-03-15T23:59:59.000Z

    The authors investigated the characteristics of Nb-doped In{sub 2}O{sub 3} (INbO) films prepared by co-sputtering of Nb{sub 2}O{sub 5} and In{sub 2}O{sub 3} for use in transparent anodes for organic solar cells (OSCs). To optimize the Nb dopant composition in the In{sub 2}O{sub 3} matrix, the effect of the Nb doping power on the resistivity and transparency of the INbO films were examined. The electronic structure and microstructure of the INbO films were also investigated using synchrotron x-ray absorption spectroscopy and x-ray diffraction examinations in detail. At the optimized Nb co-sputtering power of 30?W, the INbO film exhibited a sheet resistance of 15??/sq, and an optical transmittance of 86.04% at 550?nm, which are highly acceptable for the use as transparent electrodes in the fabrication of OSCs. More importantly, the comparable power conversion efficiency (3.34%) of the OSC with an INbO anode with that (3.31%) of an OSC with a commercial ITO anode indicates that INbO films are promising as a transparent electrode for high performance OSCs.

  15. Isothermal oxidation behavior of ternary Zr-Nb-Y alloys at high temperature

    SciTech Connect (OSTI)

    Prajitno, Djoko Hadi, E-mail: djokohp@batan.go.id [Research Center for Nuclear Materials and Radiometry, Jl. Tamansari 71, Bandung 40132 (Indonesia); Soepriyanto, Syoni; Basuki, Eddy Agus [Metallurgy Engineering, Institute Technology Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Wiryolukito, Slameto [Materials Engineering, Institute Technology Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

    2014-03-24T23:59:59.000Z

    The effect of yttrium content on isothermal oxidation behavior of Zr-2,5%Nb-0,5%Y, Zr-2,5%Nb-1%Y Zr-2,5%Nb-1,5%Y alloy at high temperature has been studied. High temperature oxidation carried out at tube furnace in air at 600,700 and 800°C for 1 hour. Optical microscope is used for microstructure characterization of the alloy. Oxidized and un oxidized specimen was characterized by x-ray diffraction. In this study, kinetic oxidation of Zr-2,5%Nb with different Y content at high temperature has also been studied. Characterization by optical microscope showed that microstructure of Zr-Nb-Y alloys relatively unchanged and showed equiaxed microstructure. X-ray diffraction of the alloys depicted that the oxide scale formed during oxidation of zirconium alloys is monoclinic ZrO2 while unoxidised alloy showed two phase ? and ? phase. SEM-EDS examination shows that depletion of Zr composition took place under the oxide layer. Kinetic rate of oxidation of zirconium alloy showed that increasing oxidation temperature will increase oxidation rate but increasing yttrium content in the alloys will decrease oxidation rate.

  16. A simple growth method for Nb?O? films and their optical properties

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Dash, J. K.; Kisslinger, K.; Chen, L.; Topka, Michael R.; Dinolfo, Peter H.; Zhang, L. H.; Lu, T. -M.; Wang, G. -C.

    2015-01-01T23:59:59.000Z

    A simple method for the synthesis of Nb?O? films of thicknesses ranging from tens to several hundreds of nanometers on amorphous silicon dioxide or quartz substrates is presented. Nb?O? films were formed by annealing the sputter deposited Nb films under an Ar flow and without oxygen plasma in a quartz tube within a furnace at 850 °C. The structural, compositional, optical, and vibrational properties were characterized by grazing incidence X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet visible spectroscopy, and Raman scattering. Each of the Nb?O? films is polycrystalline with an orthorhombic crystal structure. We observed vibrational modes includingmore »longitudinal optical, transverse optical, and triply degenerate modes, and measured the indirect optical band gap to be ~3.65 eV. The transmittance spectrum of the ~20 nm thick Nb?O? film shows over 90% transmittance below the band gap energy in the visible wavelength range and decreases to less than 20% in the ultraviolet regime. The optical properties of the films in the UV-vis range show potential applications as UV detectors.« less

  17. The high-strain-rate and spallation response of tantalum, Ta-10W, and T-111

    SciTech Connect (OSTI)

    Gray, G.T. III; Rollett, A.D.

    1991-01-01T23:59:59.000Z

    The compressive true stress-true response of tantalum, Ta-10W, and T-111 were found to depend on the applied strain rate, in the range 0.001 to 7000 s{sup {minus}1}. The strain-rate sensitivities of the flow stress of tantalum, Ta-10W, and T-111 a 1% strain are 0.062, 0.031, and 0.024, respectively. The rates of strain hardening in Tantalum, Ta-10W, and T-111 are seen to exhibit differing behavior with increasing strain rate. The calculated average strain-hardening rate in tantalum, {Theta}, for the quasi-static (0.001 s{sup {minus}1}) data at 25{degrees}C is 2080 MPa/unit strain. The hardening rate at 3000s{sup {minus}1} at 25{degrees}C decreases to 846 MPa/unit strain. Normalizing the work hardening rate in tantalum with the Taylor Factor for a random polycrystal, ({Theta} / (3.07){sup 2}), yields work hardening rates of {mu}/276 at quasi-static strain rates and {mu}/680 at high-rates, assuming a shear modulus of 61 GPa for tantalum at room temperature. While the work hardening of all the tantalum-based materials are similar at quasi-static rates, alloying results in a small reduction in hardening rate. With increasing strain rate, the work hardening rate in tantalum decreases by approximately a factor of two compared to the alloys. Alloying tantalum with substitutional or interstitial elements is thought to result in increased edge dislocation storage and screw dislocation cross-slip due to interactions with the alloying elements at high strain rates. 28 refs.

  18. Seismic Vulnerability Assessment Waste Characterization Reduction and Repackaging Building, TA-50-69

    SciTech Connect (OSTI)

    M.W.Sullivan; J.Ruminer; I.Cuesta

    2003-02-02T23:59:59.000Z

    This report presents the results of the seismic structural analyses completed on the Waste Characterization Reduction and Repackaging (WCRR) Building in support of ongoing safety analyses. WCRR is designated as TA-50-69 at Los Alamos National Laboratory, Los Alamos, New Mexico. The facility has been evaluated against Department of Energy (DOE) seismic criteria for Natural Phenomena Hazards (NPH) Performance Category II (PC 2). The seismic capacities of two subsystems within the WCRR building, the material handling glove box and the lift rack immediately adjacent to the Glove Box are also documented, and the results are presented.

  19. Emission patterns of neutral pions in 40 A MeV Ta+Au reactions

    E-Print Network [OSTI]

    K. Piasecki; T. Matulewicz; N. Yahlali; H. Delagrange; J. Díaz; D. G. d'Enterria; F. Fernández; A. Kugler; H. Löhner; G. Martínez-García; R. W. Ostendorf; Y. Schutz; P. Tlustý; R. Turrisi; V. Wagner; H. W. Wilschut

    2010-04-16T23:59:59.000Z

    Differential cross sections of neutral pions emitted in 181Ta + 197Au collisions at a beam energy of 39.5A MeV have been measured with the photon spectrometer TAPS. The kinetic energy and transverse momentum spectra of neutral pions cannot be properly described in the framework of the thermal model, nor when the reabsorption of pions is accounted for in a phenomenological model. However, high energy and high momentum tails of the pion spectra can be well fitted through thermal distributions with unexpectedly soft temperature parameters below 10 MeV.

  20. The effect of Ta on the magnetic thickness of permalloy (Ni{sub 81}Fe{sub 19}) films

    SciTech Connect (OSTI)

    Kowalewski, M. [Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] [Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Butler, W. H. [Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] [Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Moghadam, N. [Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] [Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Stocks, G. M. [Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] [Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Schulthess, T. C. [Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] [Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Song, K. J. [Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] [Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Thompson, J. R. [Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] [Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Arrott, A. S. [Honeywell, Inc., MN14-3C15, 12001 State Highway 55, Plymouth, Minnesota 55441 (United States)] [Honeywell, Inc., MN14-3C15, 12001 State Highway 55, Plymouth, Minnesota 55441 (United States); Zhu, T. [Honeywell, Inc., MN14-3C15, 12001 State Highway 55, Plymouth, Minnesota 55441 (United States)] [Honeywell, Inc., MN14-3C15, 12001 State Highway 55, Plymouth, Minnesota 55441 (United States); Drewes, J. [Honeywell, Inc., MN14-3C15, 12001 State Highway 55, Plymouth, Minnesota 55441 (United States)] (and others) [Honeywell, Inc., MN14-3C15, 12001 State Highway 55, Plymouth, Minnesota 55441 (United States)

    2000-05-01T23:59:59.000Z

    The effect of Ta and Ta/Cu seed layers, and Ta and Cu cap layers on the effective magnetic thickness of ultrathin permalloy (Ni{sub 81}Fe{sub 19}) was investigated for MRAM applications. The films were deposited by Ion Beam Deposition. The magnetic moment of each as-deposited permalloy film was measured using a B-H looper and a SQUID magnetometer. The films were further annealed at either 525 K for 1/2 h or 600 K for 1 h to study the effect of thermally driven interdiffusion on the magnetic moment of the permalloy film. Our theoretical calculations showed that the presence of 12% intermixing at the interface reduces the Ni moments to zero. Experimentally, it was shown that the tantalum rather than the copper interfaces are primarily responsible for the magnetically dead layers. The Ta seed layer interface produces a loss of moment equivalent to a magnetically dead layer of thickness 0.6{+-}0.2 nm. The Ta metal in the cap layer results in a loss of moment equivalent to a dead layer of thickness 1.0{+-}0.2 nm. Upon annealing, thermally driven interdiffusion is concluded to have a strong effect on the Ta(seed)/ Ni{sub 81}Fe{sub 19} as-deposited interface, based on the doubling of the magnetically dead layer to 1.2{+-}0.2 nm. The Ni{sub 81}Fe{sub 19}/Ta(cap) as-deposited interface slightly increases its equivalent magnetically dead layer upon annealing to 1.2{+-}0.2 nm. As-deposited interfaces of Ta(seed)/permalloy and permalloy/Ta(cap) are not chemically equivalent and result in different magnetically dead layers, whereas after annealing to 600 K both interfaces attain comparable intermixing and magnetically dead layers. It was also shown that a half-hour anneal at the lower 525 K annealing temperature, which is closer to the actual processing temperature, results in only slight increase of the magnetically dead layer at both interfaces. (c) 2000 American Institute of Physics.

  1. CHANGES IN THE ELECTRICAL SURFACE CHARGE AND TRANSPLANTATION PROPERTIES OF TA3 ASCITES TUMOR CELLS DURING SHORT-TERM MAINTENANCE IN AN ISOTONIC SALT SOLUTION

    E-Print Network [OSTI]

    Tenforde, T.S.

    2013-01-01T23:59:59.000Z

    CELLS DURING SHORT-TERM MAINTENANCE IN AN ISOTONIC SALTcells. In conclusion, the maintenance of TA3 ascites cellslhort-term tumor cell maintenance in vitro. REFERENCES

  2. Effects of Nb doping level on the electronic transport, photoelectric effect and magnetoresistance across La{sub 0.5}Ca{sub 0.5}MnO{sub 3}/Nb:SrTiO{sub 3} junctions

    SciTech Connect (OSTI)

    Wang, J. F., E-mail: jifewang@gmail.com [Department of Physics, The University of Hong Kong, Pokfulam Road (Hong Kong); College of Science, China Jiliang University, Hangzhou, Zhejiang 310018 (China); Jiang, Y. C.; Gao, J., E-mail: jugao@hku.hk [Department of Physics, The University of Hong Kong, Pokfulam Road (Hong Kong); Chen, M. G. [College of Science, China Jiliang University, Hangzhou, Zhejiang 310018 (China)] [College of Science, China Jiliang University, Hangzhou, Zhejiang 310018 (China)

    2013-12-16T23:59:59.000Z

    Heterojunctions composed of La{sub 0.5}Ca{sub 0.5}MnO{sub 3} and Nb doped SrTiO{sub 3} were fabricated, and the effects of the Nb doping level on their electronic transport, photoelectric effect, and magnetoresistance were investigated. A lower doping concentration of Nb led to better rectifying properties and higher open circuit voltages. The I-V curves for La{sub 0.5}Ca{sub 0.5}MnO{sub 3}/0.7?wt.?% Nb-SrTiO{sub 3} showed a negligible response to magnetic fields for all temperatures, whereas La{sub 0.5}Ca{sub 0.5}MnO{sub 3}/0.05?wt.?% Nb-SrTiO{sub 3} exhibited distinct magnetoresistance, which depended on both the bias voltage and temperature. These results are discussed with the assistance of conventional semiconductor theories.

  3. Creep strength of niobium alloys, Nb-1%Zr and PWC-11

    SciTech Connect (OSTI)

    Titran, R.H.

    1990-01-01T23:59:59.000Z

    A study is being conducted at NASA Lewis Research Center to determine the feasibility of using a carbide particle strengthened Nb-1% Zr base alloy to meet the anticipated temperature and creep resistance requirements of proposed near term space power systems. In order to provide information to aid in the determination of the suitability of the PWC-11 alloy as an alternative to Nb-1% Zr in space power systems this study investigated (1) the long-time high-vacuum creep behavior of the PWC-11 material and the Nb-1% Zr alloy, (2) the effect of prior stress-free thermal aging on this creep behavior, (3) the effect of electron beam (EB) welding on this creep behavior, and (4) the stability of creep strengthening carbide particles. 14 refs., 5 figs., 2 tabs.

  4. Construction and Test of 3.6 m Nb3Sn Racetrack Coils for LARP

    SciTech Connect (OSTI)

    Wanderer, P.; Ambrosio, G.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Cheng, D. W.; Cozzolino, J.; Dietderich, D.R.; Escallier, J.; Feher, S.; Ferracin, P.; Ganetis, G.; Ghosh, A. K.; Gupta, R. C.; Hafalia,, A. R.; Hannaford, C. R.; Joshi, P.; Kovach, P.; Lietzke, A. F.; Lizarazo, J.; Louie, W.; Marone, A.; McInturff, A.D.; Muratore, J.; Nobrega, F.; Sabbi, G.; Schmalzle, J.; Thomas, R.; Turrioni, D.

    2008-06-01T23:59:59.000Z

    Development of high-performance Nb{sub 3}Sn quadrupoles is one of the major goals of the LHC Accelerator Research Program (LARP). As part of this program, long racetrack magnets were made in order to check the fabrication steps for long Nb{sub 3}Sn coils, that the changes in coil length that take place during reaction and cooldown are correctly accounted for in the quadrupole design, and the use of a long aluminum shell for the support structure. This paper reports the construction of the first long Nb{sub 3}Sn magnet with racetrack coils 3.6 m long. The magnet reached a nominal 'plateau' at 9596 A after five quenches. This is about 90% of the estimated conductor limit. The peak field in the coils at this current was 11 T.

  5. Effect of Axial Loading on Quench Performance in Nb3Sn Magnets

    SciTech Connect (OSTI)

    Ambrosio, G.; Bordini, B.; Caspi, S.; Dietderich, D.R.; Felice, H.; Hafalia, A.R.; Hannaford, C.R.; Lizarazo, J.; Lietzke, A.F.; McInturff, A.D.; Sabbi, G.L.; DiMarco, J.D.; Tartaglia, M.; Vedrice, P.; Ferracin, P.

    2008-06-01T23:59:59.000Z

    A series of tests has been performed at Lawrence Berkeley National Laboratory (LBNL) and Fermi National Accelerator Laboratory (FNAL) with the goal of assessing the influence of coil axial pre-load on Nb{sub 3}Sn magnet training. The tests involved two subscale Nb{sub 3}Sn magnets: SQ02, a quadrupole magnet fabricated as part of the US LHC Accelerator Research Program (LARP), and SD01, a dipole magnet developed in collaboration between CEA/Saclay and LBNL. Both magnets used similar Nb{sub 3}Sn flat racetrack coils from LBNL Subscale Magnet Program, and implemented an axial support system composed of stainless steel end-plates and aluminum rods. The system was designed to withstand full longitudinal electro-magnetic forces and provide controllable preloads. Quench performances, training, and quench locations have been recorded in various axial loading conditions. Test results are reported.

  6. Construction and Test of 3.5 m Nb3Sn Racetrack Coils for LARP.

    SciTech Connect (OSTI)

    Wanderer,P.; Ambrosio, G.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Cheng, D.W.; Cozzolino, J.; Dietderich, D.R.; Escallier, J.; Feher, S.; Ferracin, P.; Ganetis, G.; Ghosh, A.K.; Gupta, R.C.; Hafalia, A.R.; Hannaford, C.R.; Joshi, P.; Kovach, P.; Lietzke, A.F.; Lizarazo, J.; Louie, W.; Marone, A.; McInturff, A.D.; Muratore, J.; Nobrega, R.; Sabbi, G.; Schmalzle, J.; Thomas, R.; Turrioni, D.

    2007-08-27T23:59:59.000Z

    Development of high-performance Nb{sub 3}Sn quadrupoles is one of the major goals of the LHC Accelerator Research Program (LARP). As part of this program, long racetrack magnets were made in order to check the fabrication steps for long Nb{sub 3}Sn coils, that the changes in coil length that take place during reaction and cooldown are correctly accounted for in the quadrupole design, and the use of a long aluminum shell for the support structure. This paper reports the construction of the first long Nb{sub 3}Sn magnet with racetrack coils 3.6 m long. The magnet reached a nominal 'plateau' at 9596 A after five quenches. This is about 90% of the estimated conductor limit. The peak field in the coils at this current was 11 T.

  7. ECR Nb Films Grown on Amorphous and Crystalline Cu Substrates: Influence of Ion Energy

    SciTech Connect (OSTI)

    Valente, Anne-Marie [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Eremeev, Grigory V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Spradlin, Joshua K. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Phillips, H. Lawrence [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Reece, Charles E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Cao, C. [Illinois Inst. of Technology, Chicago, IL (United States); Proslier, Thomas [Argonne National Laboratory, Argonne, IL (United States); Tao, T. [Univ. of Illinois at Chicago, Chicago, IL (United States)

    2014-02-01T23:59:59.000Z

    In the pursuit of niobium (Nb) films with similar performance with the commonly used bulk Nb surfaces for Superconducting RF (SRF) applications, significant progress has been made with the development of energetic condensation deposition techniques. Using energetic condensation of ions extracted from plasma generated by Electron Cyclotron Resonance, it has been demonstrated that Nb films with good structural properties and RRR comparable to bulk values can be produced on metallic substrates. The controlled incoming ion energy enables a number of processes such as desorption of adsorbed species, enhanced mobility of surface atoms and sub-implantation of impinging ions, thus producing improved film structures at lower process temperatures. Particular attention is given to the nucleation conditions to create a favourable template for growing the final surface exposed to SRF fields. The influence of the deposition energy on film growth on copper substrates is investigated with the characterization of the film surface, structure, superconducting properties and RF performance.

  8. Microstructure and Mechanical Behaviour of NbTiAl based alloys doped with low additions of silicon

    E-Print Network [OSTI]

    1 Microstructure and Mechanical Behaviour of NbTiAl based alloys doped with low additions Aerospace Lab, F-91761 Palaiseau, France zhao.zhao@onera.fr , anne.denquin@onera.fr , stefan.drawin@onera.fr , jonathan.barreau@onera.fr Keywords: Nb-base alloy; Silicides; Niobium aluminides; Phase transformation

  9. Flux penetration into superconducting Nb3Sn in oblique magnetic fields Diana G. Gheorghe, Mariela Menghini, and Rinke J. Wijngaarden

    E-Print Network [OSTI]

    Wijngaarden, Rinke J.

    Flux penetration into superconducting Nb3Sn in oblique magnetic fields Diana G. Gheorghe, Mariela; published 14 June 2006 Penetration of magnetic flux into a rectangular platelet of superconducting Nb3Sn-II superconductors. For such an analysis, often the simplest solutions of the critical state problem are used, which

  10. A new anatase-type phase in the system Mg-Ta-O-N

    SciTech Connect (OSTI)

    Schilling, H. [Institut fuer Chemie, TU Berlin, Strasse des 17. Juni 135, D-10623 Berlin (Germany); Lerch, M. [Institut fuer Chemie, TU Berlin, Strasse des 17. Juni 135, D-10623 Berlin (Germany)]. E-mail: lerch@chem.tu-berlin.de; Boerger, A. [Institut fuer Physikalische und Theoretische Chemie, TU Braunschweig, Hans-Sommer-Str. 10, D-38106 Braunschweig (Germany); Becker, K.-D. [Institut fuer Physikalische und Theoretische Chemie, TU Braunschweig, Hans-Sommer-Str. 10, D-38106 Braunschweig (Germany); Wolff, H. [Institut fuer Anorganische Chemie, RWTH Aachen, Landoldtweg 1, D-52056 Aachen (Germany); Dronskowski, R. [Institut fuer Anorganische Chemie, RWTH Aachen, Landoldtweg 1, D-52056 Aachen (Germany); Bredow, T. [Theoretische Chemie, Universitaet Hannover, Am Kleinen Felde 30, D-30167 Hannover (Germany); Tovar, M. [Hahn-Meitner-Institut Berlin, Glienicker Str. 100, D-14109 Berlin (Germany); Baehtz, C. [HASYLAB at DESY, Notkestr. 85, D-22603 Hamburg (Germany)

    2006-08-15T23:59:59.000Z

    Magnesium doped tantalum oxynitrides were prepared by ammonolysis of amorphous mixed oxides. An orange colored anatase-type phase with the composition Mg{sub 0.05}Ta{sub 0.95}O{sub 1.15}N{sub 0.85} was found. It is metastable and undergoes a phase transformation to a baddeleyite-type phase between 900 and 1000deg. C. X-ray diffraction measurements indicate spacegroup I4{sub 1}/amd with lattice parameters a=391.986(6)pm and c=1011.19(3)pm. A possible anion ordering was examined by theoretical methods and neutron diffraction experiments. In addition, anosovite-type (Ti{sub 3}O{sub 5}) phases Mg{sub x}Ta{sub 3-x}O{sub 3x}N{sub 5-3x}; 0=

  11. Polytypism, polymorphism, and superconductivity in TaSe2-xTex

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Luo, Huixia; Tao, Jing; Xie, Weiwei; Inoue, Hiroyuki; Gyenis, Andras; Krizan, Jason W.; Yazdani, Ali; Zhu, Yimei; Cava, R. J.

    2015-03-17T23:59:59.000Z

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

  12. High spin states in {sup 175}Ta: An acute example of delayed crossing frequency

    SciTech Connect (OSTI)

    Wen, S.; Zheng, H.; Li, S.; Li, G.; Yuan, G.; Hua, P.; Weng, P.; Zhang, L.; Yu, P.; Yang, C. [China Institute of Atomic Energy, P.O. Box 275, Beijing 102413, People`s Republic of (China)] [China Institute of Atomic Energy, P.O. Box 275, Beijing 102413, People`s Republic of (China); Sun, H.; Liu, Y.; Liu, Y. [Department of Physics, Jilin University, Changchun, Jilin 130023, People`s Republic of (China)] [Department of Physics, Jilin University, Changchun, Jilin 130023, People`s Republic of (China); Sun, Y.; Feng, D.H. [Department of Physics and Atmospheric Science, Drexel University, Philadelphia, Pennsylvania 19104 (United States)] [Department of Physics and Atmospheric Science, Drexel University, Philadelphia, Pennsylvania 19104 (United States)

    1996-09-01T23:59:59.000Z

    High spin states in {sup 175}Ta are populated by the {sup 160}Gd ({sup 19}F,4{ital n}) {sup 175}Ta reaction. This experiment, carried out at the HI-13 tandem accelerator at the China Institute of Atomic Energy which measured the {gamma}-{gamma} coincidences, gives rise to a new level scheme. Two important new features are embedded in this scheme. First, the seven decay sequences built on 1/2 [541], 7/2 [404], 5/2 [402], and 9/2 [514] proton Nilsson configurations are significantly extended to higher spins. For example, for the 1/2 [541] band, the levels have extended from 33/2{sup {minus}} to 61/2{sup {minus}} and, for the 7/2 [404] band, from 21/2{sup {minus}} to 41/2{sup {minus}}. Second, compared to the neighboring even-even nuclides, the neutron {ital AB} crossing frequency built on the {ital h}{sub 9/2} proton Nilsson state 1/2 [541] is significantly larger, which according to the conventional cranking shell model (CSM) is an anomaly. In this paper, this large crossing frequency is also discussed within the framework of the projected shell model. It is shown that this anomaly found in CSM can be satisfactorily explained, thus suggesting an alternative understanding. {copyright} {ital 1996 The American Physical Society.}

  13. Film Deposition, Cryogenic RF Testing and Materials Analysis of a Nb/Cu Single Cell SRF Cavity

    SciTech Connect (OSTI)

    Zhao, Xin [JLAB; Geng, Rongli [JLAB; Palczerski, Ari [JLAB; Li, Yongming [Peking

    2013-09-01T23:59:59.000Z

    In this study, we present preliminary results on using a cathodic-arc-discharge Nb plasma ion source to establish a Nb film-coated single-cell Cu cavity for SRF research. The polycrystalline Cu cavity was fabricated and mirror-surface-finished by a centrifugal barrel polishing (CBP) process at Jefferson Lab. Special pre-coating processes were conducted, in order to create a template-layer for follow-on Nb grain thickening. A sequence of cryogenic RF testing demonstrated that the Nb film does show superconductivity. But the quality factor of this Nb/Cu cavity is low as a result of high residual surface resistance. We are conducting a thorough materials characterization to explore if some microstructural defects or hydrogen impurities, led to such a low quality factor.

  14. Design of HQ -- a High Field Large Bore Nb3Sn Quadrupole Magnet for LARP

    SciTech Connect (OSTI)

    Felice, H.; Ambrosio, G.; Anerella, M.; Bossert, R.; Caspi, S.; Cheng, D.; Dietderich, D.; Ferracin, P.; Ghosh, A. K.; Hafalia, R.; Hannaford, C. R.; Kashikhin, V.; Schmalze, J.; Prestemon, S.; Sabbi, G. L.; Wanderer, P.; Zlobin, A. V.

    2008-08-17T23:59:59.000Z

    In support of the Large Hadron Collider luminosity upgrade, a large bore (120 mm) Nb{sub 3}Sn quadrupole with 15 T peak coil field is being developed within the framework of the US LHC Accelerator Research Program (LARP). The 2-layer design with a 15 mm wide cable is aimed at pre-stress control, alignment and field quality while exploring the magnet performance limits in terms of gradient, forces and stresses. In addition, HQ will determine the magnetic, mechanical, and thermal margins of Nb{sub 3}Sn technology with respect to the requirements of the luminosity upgrade at the LHC.

  15. The problem of intermixing of metals possessing no mutual solubility upon explosion welding (Cu-Ta, Fe-Ag, Al-Ta)

    SciTech Connect (OSTI)

    Greenberg, B.A., E-mail: bella@imp.uran.ru [Institute of Metal Physics, Ural Branch, Russian Academy of Sciences, S. Kovalevskoi str. 18, Ekaterinburg, 620990 (Russian Federation); Ivanov, M.A. [Kurdyumov Institute of Metal Physics, National Academy of Sciences of Ukraine, Vernadskogo blvd. 36, Kiev, 03680 (Ukraine)] [Kurdyumov Institute of Metal Physics, National Academy of Sciences of Ukraine, Vernadskogo blvd. 36, Kiev, 03680 (Ukraine); Rybin, V.V. [State Polytechnical University, Politekhnicheskaya str. 29, St. Petersburg, 195251 (Russian Federation)] [State Polytechnical University, Politekhnicheskaya str. 29, St. Petersburg, 195251 (Russian Federation); Elkina, O.A.; Antonova, O.V.; Patselov, A.M.; Inozemtsev, A.V.; Plotnikov, A.V.; Volkova, A.Yu. [Institute of Metal Physics, Ural Branch, Russian Academy of Sciences, S. Kovalevskoi str. 18, Ekaterinburg, 620990 (Russian Federation)] [Institute of Metal Physics, Ural Branch, Russian Academy of Sciences, S. Kovalevskoi str. 18, Ekaterinburg, 620990 (Russian Federation); Besshaposhnikov, Yu.P. [OJSC Ural Chemical Machine Building Plant, Khibinogorskii Lane 33, Ekaterinburg, 620010 (Russian Federation)] [OJSC Ural Chemical Machine Building Plant, Khibinogorskii Lane 33, Ekaterinburg, 620010 (Russian Federation)

    2013-01-15T23:59:59.000Z

    On the basis of the results obtained for joints of dissimilar metals such as copper-tantalum and iron-silver, the reason of immiscible suspensions mixing upon explosion welding has been cleared out. It has been found that the interface (plain or wavy) is not smooth and contains inhomogeneities, namely, cusps and local melting zones. The role of granulating fragmentation providing partitioning of initial materials as a main channel of input energy dissipation has been revealed. It has been shown that in joints of metals possessing normal solubility the local melting zones are true solutions, but if metals possess no mutual solubility the local melting zones are colloidal solutions. Realization of either emulsion or suspension variant takes place. The results can be used in the development of new joints of metals possessing no mutual solubility. - Highlights: Black-Right-Pointing-Pointer Immiscible pairs Ta/Cu and Fe/Ag are welded successfully by explosive welding. Black-Right-Pointing-Pointer Fragmentation provides for partitioning as the main energy dissipation channel. Black-Right-Pointing-Pointer Immiscible metals form colloidal solid solutions during solidification. Black-Right-Pointing-Pointer Melting and boiling temperatures ratio determines the colloidal solution type. Black-Right-Pointing-Pointer Local melting zones being in suspension form enhance welds hardening.

  16. DB Climate Change Advisors DBCCA | 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 directedAnnualProperty EditCalifornia:PowerCER.pngRoofs andCrops Ltd Jump to: navigation, search Name:DB

  17. Processing of U-2.5Zr-7.5Nb and U-3Zr-9Nb alloys by sintering process

    SciTech Connect (OSTI)

    Dos Santos, A. M. M.; Ferraz, W. B.; Lameiras, F. S.; Mazzeu, T. D. O. [Centro de Desenvolvimento da Tecnologia Nuclear, CDTN-CNEN, Av. Presidente Antionio Carlos 6.627, 31270-901 Belo Horizonte, MG (Brazil)

    2012-07-01T23:59:59.000Z

    To minimize the risk of nuclear proliferation, there is worldwide interest in reducing fuel enrichment of research and test reactors. To achieve this objective while still guaranteeing criticality and cycle length requirements, there is need of developing high density uranium metallic fuels. Alloying elements such as Zr, Nb and Mo are added to uranium to improve fuel performance in reactors. In this context, the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN) is developing the U-2.5Zr-7.5Nb and U-3Zr-9Nb (weight %) alloys by the innovative process of sintering that utilizes raw materials in the form of powders. The powders were pressed at 400 MPa and then sintered under a vacuum of about 1x10{sup -4} Torr at temperatures ranging from 1050 deg. to 1500 deg.C. The densities of the alloys were measured geometrically and by hydrostatic method and the phases identified by X ray diffraction (XRD). The microstructures of the pellets were observed by scanning electron microscopy (SEM) and the alloying elements were analyzed by energy dispersive X-ray spectroscopy (EDS). The results obtained showed the fuel density to slightly increase with the sintering temperature. The highest density achieved was approximately 80% of theoretical density. It was observed in the pellets a superficial oxide layer formed during the sintering process. (authors)

  18. Adsorption of CO on Pd/Al2O3/Ta(110) model catalysts D. R. Rainer, M.-C. Wu, D. I. Mahon, and D. W. Goodmana)

    E-Print Network [OSTI]

    Goodman, Wayne

    Adsorption of CO on Pd/Al2O3/Ta(110) model catalysts D. R. Rainer, M.-C. Wu, D. I. Mahon, and D. W October 1995; accepted 22 January 1996 The adsorption of CO on Pd/Al2O3/Ta 110 model catalysts was studied using infrared reflection adsorption spectroscopy IRAS for two different Pd coverages, corresponding

  19. Selective etching of TiN over TaN and vice versa in chlorine-containing Hyungjoo Shin,a)

    E-Print Network [OSTI]

    Economou, Demetre J.

    Selective etching of TiN over TaN and vice versa in chlorine-containing plasmas Hyungjoo Shin 1 April 2013; published 18 April 2013) Selectivity of etching between physical vapor-deposited TiN selectivity of etching TiN over TaN by adding small amounts (

  20. Structural aspects of glass-formation in Ni-Nb melts

    SciTech Connect (OSTI)

    Holland-Moritz, D.; Yang, F.; Gegner, J.; Meyer, A. [Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln (Germany); Hansen, T. [Institut Laue-Langevin (ILL), 38042 Grenoble (France); Ruiz-Martín, M. D. [Grup de Caracterització de Materials, Departament de Física i Enginyeria Nuclear, Universitat Politčcnica de Catalunya, Barcelona (Spain); Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln (Germany)

    2014-05-28T23:59:59.000Z

    We report on investigations of the static structure factors of glass-forming Ni{sub 59.5}Nb{sub 40.5} alloy melts by combination of the containerless processing technique of electrostatic levitation with neutron diffraction. By application of the isotopic substitution method, the full set of partial structure factors was determined. The short-range order in liquid Ni{sub 59.5}Nb{sub 40.5} is characterized by a large nearest neighbor coordination number of Z{sub NN}?=?14.3 and a chemical short-range order with an affinity for the formation of heterogeneous Nb-Ni nearest neighbors. The structure factors observed here in the liquid state closely resemble those reported for amorphous Nb-Ni solids. The comparison with earlier results on the short-range structure in Zr-based glass-forming melts suggests that a large local density of packing, chemical order, and structural frustration are, amongst others, common structural properties of these metallic glass-forming systems, which favor glass-formation.

  1. Irradiation requirements of Nb3Sn based SC magnets electrical insulation

    E-Print Network [OSTI]

    McDonald, Kirk

    Irradiation requirements of Nb3Sn based SC magnets electrical insulation developed within the Eu electrical insulation candidates · EuCARD insulators certification conditions · Post irradiation tests and neutrino factories will be subjected to very high radiation doses. · The electrical insulation employed

  2. Instrumentation for Measurement of Strain Dependence of Nb3Sn Conductors National High Magnetic Field Laboratory

    E-Print Network [OSTI]

    Weston, Ken

    Instrumentation for Measurement of Strain Dependence of Nb3Sn Conductors National High Magnetic Field Laboratory Magnet Science and Technology, Florida State University An NHMFL User Collaboration Grants Program (UCGP) award is supporting students from the FAMU-FSU College of Engineering as part

  3. Selected materials development for the 100 T magnet: Cu-Nb conductors with

    E-Print Network [OSTI]

    Weston, Ken

    Selected materials development for the 100 T magnet: Cu-Nb conductors with nanocomposite components (PBO) based composite for reinforcement Materials R&D for the 100-Tesla Pulsed Magnet Gregory S for this achievement was the long-term and painstaking research and development of high strength materials

  4. Properties of Porous TiNbZr Shape Memory Alloy Fabricated by Mechanical Alloying

    E-Print Network [OSTI]

    Zheng, Yufeng

    , with subsequent hot or cold rolling, were used to fabricate these Ni-free SMAs. There is no work related to powder in the specimen prepared by conventional sintering. X-ray diffraction analysis showed that the solid solution 16, 2011) In the past decades, systematic researches have been focused on studying Ti-Nb-based SMAs

  5. Inhibition of Cell Growth by NB1011 Requires High Thymidylate Synthase Levels and Correlates with

    E-Print Network [OSTI]

    Wahl, Geoffrey M.

    cells, whereas no induction was observed in low TS- expressing tumor cells (MCF7) or normal cells (WI38). Cell cycle analysis demonstrated that NB1011 treatment of MCF7TDX and RKOTDX cells resulted established Tomudex-resistant breast cancer (MCF7TDX) xenografts in athymic mice. Against 5-fluorouracil

  6. Commensurability effects induced by a periodic array of nanoscale anti-dots in Nb superconductor

    E-Print Network [OSTI]

    Metlushko, Vitali

    Commensurability effects induced by a periodic array of nanoscale anti-dots in Nb superconductor A. PACS: 74.25.Ha; 74.76.)w Keywords: Nanostructures; Anti-dots; Commensurability 1. Introduction atomic layers on periodical substrate [5], magnetic bubble arrays [6] and the magnetically induced Wigner

  7. Amorphous Nb/Fe-oxide ion-storage films for counter electrode applications in electrochromic devices

    SciTech Connect (OSTI)

    Orel, B.; Macek, M.; Lavrencic-Stangar, U. [National Inst. of Chemistry, Ljubljana (Slovenia); Pihlar, B. [Univ. of Ljubljana (Slovenia). Faculty of Chemistry

    1998-05-01T23:59:59.000Z

    The electrochromic properties of mixed Nb/Fe-oxide films with amorphous structure which were prepared via the sol-gel route were determined. Films with Nb/Fe molar concentration ratios 0.2:1, 0.4:1, and 1:1 exhibit ion-storage capacities up to 18 mC/cm{sup 2} depending on Nb/Fe molar ratio. Electrochromically films behave as optically passive electrodes with a coloration efficiency of nearly zero at {lambda} > 480 nm, while at shorter wavelengths a relatively strong anodic coloring was observed, yielding negative coloration efficiencies up to {minus}20 cm{sup 2}/C. Coloring/bleaching changes of films are correlated with the ex situ IR spectroscopic measurements of charged/discharged films showing distortions of the film structure with Li{sup +} ion insertion/extraction reactions. Electrochemical stability of Nb/Fe (0.4:1)-oxide films was tested up to 2,000 cycles in a sol-gel electrochromic device consisting of sol-gel-derived WO{sub 3} films and hybrid organic/inorganic ionic conductor with ionic conductivity of about 10{sup {minus}4} S/cm serving for lamination of the electrodes.

  8. Coupled displacive and orderdisorder dynamics in LiNbO3 by molecular-dynamics simulation

    E-Print Network [OSTI]

    Gopalan, Venkatraman

    .1063/1.1669063 Ferroelectric lithium niobate (LiNbO3) has emerged as an important material in surface acoustic wave devices1 the structure and properties of materials. Indeed, atomic-level simulations have been used previously-dynamics MD simulations described here we treat the Coulomb interactions using a direct summation method

  9. Logarithmic Fermi-liquid breakdown in NbFe2 M. Brando,1,

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    temperature dependence of the Sommerfeld coefficient = C/T of the specific heat capacity, C, over nearly two temperature dependences of the resistivity and of the heat capacity over extended ranges in temperatureLogarithmic Fermi-liquid breakdown in NbFe2 M. Brando,1, W. J. Duncan,1 D. Moroni-Klementowicz,1 C

  10. Design and fabrication of a stress-managed Nb3Sn wind and react dipole

    E-Print Network [OSTI]

    Noyes, Patrick Daniel

    2007-09-17T23:59:59.000Z

    A new approach to high-field dipole design is being developed at Texas A&M University. The goal of the development is to facilitate the use of high-field conductors (Nb3 and Bi-2212) and to manage Lorentz stress and magnetization so that field...

  11. A Novel Zr-1Nb Alloy and a New Look at Hydriding

    SciTech Connect (OSTI)

    Robert D. Mariani; James I. Cole; Assel Aitkaliyeva

    2013-09-01T23:59:59.000Z

    A novel Zr-1Nb has begun development based on a working model that takes into account the hydrogen permeabilities for zirconium and niobium metals. The beta-Nb secondary phase particles (SPPs) in Zr-1Nb are believed to promote more rapid hydrogen dynamics in the alloy in comparison to other zirconium alloys. Furthermore, some hydrogen release is expected at the lower temperatures corresponding to outages when the partial pressure of H2 in the coolant is less. These characteristics lessen the negative synergism between corrosion and hydriding that is otherwise observed in cladding alloys without niobium. In accord with the working model, development of nanoscale precursors was initiated to enhance the performance of existing Zr-1Nb alloys. Their characteristics and properties can be compared to oxide-dispersion strengthened alloys, and material additions have been proposed to zirconium-based LWR cladding to guard further against hydriding and to fix the size of the SPPs for microstructure stability enhancements. A preparative route is being investigated that does not require mechanical alloying, and 10 nanometer molybdenum particles have been prepared which are part of the nanoscale precursors. If successful, the approach has implications for long term dry storage of used fuel and for new routes to nanoferritic and ODS alloys.

  12. Effect of silicon on ultra-low temperature toughness of Nb–Ti microalloyed cryogenic pressure vessel steels

    SciTech Connect (OSTI)

    Qiu, J.A. [Hubei Collaborative Innovation Center for Advanced Steels, International Research Institute for Steel Technology, Wuhan University of Science and Technology, Wuhan 430081 (China); Wu, K.M., E-mail: wukaiming2000@yahoo.com [Hubei Collaborative Innovation Center for Advanced Steels, International Research Institute for Steel Technology, Wuhan University of Science and Technology, Wuhan 430081 (China); Li, J.H. [Hubei Collaborative Innovation Center for Advanced Steels, International Research Institute for Steel Technology, Wuhan University of Science and Technology, Wuhan 430081 (China); Research and Development Center of WISCO, Wuhan 430080 (China); Hodgson, P.D. [Hubei Collaborative Innovation Center for Advanced Steels, International Research Institute for Steel Technology, Wuhan University of Science and Technology, Wuhan 430081 (China); Institute for Frontier Materials, Deakin University, Geelong, Victoria 3220 (Australia); Hou, T.P. [Hubei Collaborative Innovation Center for Advanced Steels, International Research Institute for Steel Technology, Wuhan University of Science and Technology, Wuhan 430081 (China); Ding, Q.F. [Research and Development Center of WISCO, Wuhan 430080 (China)

    2013-09-15T23:59:59.000Z

    The effect of Si on the ultra-low temperature toughness of Nb–Ti microalloyed cryogenic pressure vessel steels was investigated by electron back-scattered diffraction and transmission electron microscope with energy dispersive spectroscopy. Equiaxed ferrite and bainite were obtained in the tempered steels with small Si additions. Nanosized Nb–Ti carbides (< 10 nm) were formed in the steel containing 0.05% Si, whereas much coarser carbides (> 30 nm) were found in the steel containing 0.47% Si. The ultra-low temperature toughness of the Nb–Ti microalloyed cryogenic pressure vessel steel was remarkably enhanced by the reduction in the Si content, which was attributed to the pre-existing iron carbide formation before the precipitation of nanosized Nb–Ti carbides during tempering. - Highlights: • Nanosized Nb-Ti carbides formed in the tempered steel with smaller Si addition. • Coarser Nb-Ti carbides formed in the tempered steel with more Si addition. • Pre-existing cememtites provide nucleation sites for Nb-Ti carbide precipitation. • Ultra-low temperature toughness was remarkably enhanced by Si content reduction.

  13. Preparation and characterisation of isotopically enriched Ta$_2$O$_5$ targets for nuclear astrophysics studies

    E-Print Network [OSTI]

    A. Caciolli; D. A. Scott; A. Di Leva; A. Formicola; M. Aliotta; M. Anders; A. Bellini; D. Bemmerer; C. Broggini; M. Campeggio; P. Corvisiero; R. Depalo; Z. Elekes; Zs. Fülöp; G. Gervino; A. Guglielmetti; C. Gustavino; Gy. Gyürky; G. Imbriani; M. Junker; M. Marta; R. Menegazzo; E. Napolitani; P. Prati; V. Rigato; V. Roca; C. Rolfs; C. Rossi Alvarez; E. Somorjai; C. Salvo; O. Straniero; F. Strieder; T. Szücs; F. Terrasi; H. P. Trautvetter; D. Trezzi

    2012-10-01T23:59:59.000Z

    The direct measurement of reaction cross sections at astrophysical energies often requires the use of solid targets of known thickness, isotopic composition, and stoichiometry that are able to withstand high beam currents for extended periods of time. Here, we report on the production and characterisation of isotopically enriched Ta$_2$O$_5$ targets for the study of proton-induced reactions at the Laboratory for Underground Nuclear Astrophysics facility of the Laboratori Nazionali del Gran Sasso. The targets were prepared by anodisation of tantalum backings in enriched water (up to 66% in $^{17}$O and up to 96% in $^{18}$O). Special care was devoted to minimising the presence of any contaminants that could induce unwanted background reactions with the beam in the energy region of astrophysical interest. Results from target characterisation measurements are reported, and the conclusions for proton capture measurements with these targets are drawn.

  14. Preparation and characterisation of isotopically enriched Ta$_2$O$_5$ targets for nuclear astrophysics studies

    E-Print Network [OSTI]

    Caciolli, A; Di Leva, A; Formicola, A; Aliotta, M; Anders, M; Bellini, A; Bemmerer, D; Broggini, C; Campeggio, M; Corvisiero, P; Depalo, R; Elekes, Z; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Imbriani, G; Junker, M; Marta, M; Menegazzo, R; Napolitani, E; Prati, P; Rigato, V; Roca, V; Rolfs, C; Alvarez, C Rossi; Somorjai, E; Salvo, C; Straniero, O; Strieder, F; Szücs, T; Terrasi, F; Trautvetter, H P; Trezzi, D

    2012-01-01T23:59:59.000Z

    The direct measurement of reaction cross sections at astrophysical energies often requires the use of solid targets of known thickness, isotopic composition, and stoichiometry that are able to withstand high beam currents for extended periods of time. Here, we report on the production and characterisation of isotopically enriched Ta$_2$O$_5$ targets for the study of proton-induced reactions at the Laboratory for Underground Nuclear Astrophysics facility of the Laboratori Nazionali del Gran Sasso. The targets were prepared by anodisation of tantalum backings in enriched water (up to 66% in $^{17}$O and up to 96% in $^{18}$O). Special care was devoted to minimising the presence of any contaminants that could induce unwanted background reactions with the beam in the energy region of astrophysical interest. Results from target characterisation measurements are reported, and the conclusions for proton capture measurements with these targets are drawn.

  15. Complete genome sequence of Tolumonas auensis type strain (TA 4T)

    SciTech Connect (OSTI)

    Chertkov, Olga; Copeland, Alex; Lucas1, Susa; Lapidus, Alla; Berry, KerrieW.; Detter, JohnC.; Glavina Del Rio, Tijana; Hammon, Nancy; Dalin, Eileen; Tice, Hope; Pitluck, Sam; Richardson, Paul; Bruce, David; Goodwin, Lynne; Han, Cliff; Tapia, Roxanne; Saunders, Elizabeth; Schmutz, Jeremy; Brettin, Thomas; Larimer, Frank; Land, Miriam; Hauser, Loren; Spring, Stefan; Rohde, Manfred; Kyrpides, NikosC.; Ivanova, Natalia; Göker, Markus; Beller, HarryR.; Klenk, Hans-Peter; Woyke, Tanja

    2011-10-04T23:59:59.000Z

    Tolumonas auensis (Fischer-Romero et al. 1996) is currently the only validly named species of the genus Tolumonas in the family Aeromonadaceae. The strain is of interest because of its ability to produce toluene from phenylalanine and other phenyl precursors, as well as phenol from tyrosine. This is of interest because toluene is normally considered to be a tracer of anthropogenic pollution in lakes, but T. auensis represents a biogenic source of toluene. Other than Aeromonas hydrophila subsp. hydrophila, T. auensis strain TA 4T is the only other member in the family Aeromonadaceae with a completely sequenced type-strain genome. The 3,471,292-bp chromosome with a total of 3,288 protein-coding and 116 RNA genes was sequenced as part of the DOE Joint Genome Institute Program JBEI 2008.

  16. Anisotropic Ta{sub 2}O{sub 5} waveguide etching using inductively coupled plasma etching

    SciTech Connect (OSTI)

    Muttalib, Muhammad Firdaus A., E-mail: mfam1g08@ecs.soton.ac.uk; Chen, Ruiqi Y.; Pearce, Stuart J.; Charlton, Martin D. B. [Nano Research Group, Electronics and Computer Science, Faculty of Physical and Applied Sciences, University of Southampton, Southampton SO17 1BJ (United Kingdom)

    2014-07-01T23:59:59.000Z

    Smooth and vertical sidewall profiles are required to create low loss rib and ridge waveguides for integrated optical device and solid state laser applications. In this work, inductively coupled plasma (ICP) etching processes are developed to produce high quality low loss tantalum pentoxide (Ta{sub 2}O{sub 5}) waveguides. A mixture of C{sub 4}F{sub 8} and O{sub 2} gas are used in combination with chromium (Cr) hard mask for this purpose. In this paper, the authors make a detailed investigation of the etch process parameter window. Effects of process parameters such as ICP power, platen power, gas flow, and chamber pressure on etch rate and sidewall slope angle are investigated. Chamber pressure is found to be a particularly important factor, which can be used to tune the sidewall slope angle and so prevent undercut.

  17. Equation-of-State Measurements in Ta2O5 Aerogel

    SciTech Connect (OSTI)

    Miller, J.E.; Boehly, T.R.; Meyerhofer, D.D.; Eggert, J.H.

    2008-01-14T23:59:59.000Z

    Highly porous samples of tantalum pentoxide (Ta2O5) aerogel were compressed from initial densities of 0.1, 0.15, and 0.25 g/cm^3 by shock waves with strengths between 0.3 and 3 Mbar. The compressed material was between 5 and 15 times as dense as the unshocked aerogels with temperatures ~5 eV (~58,000 K). These strong shock loadings were produced by the OMEGA Laser System at the Laboratory of Laser Energetics. The shocked states were diagnosed with the OMEGA velocity interferometer system for any reflector. When the compression measurements are compared to an available high-energy-density equation-of-state model, it is found that the model underestimates the level of compression achieved by shock loading below a Mbar.

  18. Radionuclide contaminant analysis of small mammals at Area G, TA-54, 1994

    SciTech Connect (OSTI)

    Biggs, J.; Bennett, K.; Fresquez, P.

    1995-09-01T23:59:59.000Z

    Small mammals were sampled at two waste burial sites (1 and 2) at Area G, TA-54 and a control site outside Area G (Site 3) to identify radionuclides that are present within surface and subsurface soils at waste burial sites, to compare the amount of radionuclide uptake by small mammals at waste burial sites to a control site, and to identify the primary mode of contamination to small mammals, either through surface contact or ingestion/inhalation. Three composite samples of at least five animals per sample were collected at each site. Pelts and carcasses of each animal were separated and analyzed independently. Samples were analyzed for {sup 241}Am, {sup 90}Sr, {sup 238}Pu, {sup 239}Pu, total U, and gamma spectroscopy (including {sup 137}Cs). Significantly higher (parametric t-test at p = 0.05) levels of total U, {sup 241}Am, {sup 238}Pu, {sup 239}Pu, and {sup 40}K were detected in pelts as compared to the carcasses of small mammals at TA-54. Concentrations of other measured radionuclides in carcasses were nearly equal to or exceeded the mean concentrations in the pelts. The authors results show higher concentrations in pelts compared to carcasses which is similar to what has been found at waste burial/contaminated sites outside of Los Alamos National Laboratory. Site 1 had significantly higher (alpha = 0.05, F = 0.0095) total U concentrations in carcasses than Sites 2 and 3. Site 2 had significantly higher (alpha = 0.05, F = 0.0195) {sup 239}Pu concentrations in carcasses than either Site 1 or Site 3. A significant difference in {sup 90}Sr concentration existed between Sites 1 and 2 (alpha = 0.05, F = 0.0681) and concentrations of {sup 40}K at Site 1 were significantly different from Site 3.

  19. Origin of internal field and visualization of 180 domains in congruent LiTaO3 crystals

    E-Print Network [OSTI]

    Gopalan, Venkatraman

    . Infrared absorption studies suggest that domain inversion as well as the heating of LiTaO3 crystal induce observed a strong correlation between the internal fields and the infrared absorption spectra of OH ions of the infrared absorption bands of OH ions at 3462, 3476, and 3490 cm 1 change, and c the 180° domain walls

  20. Two Particle Azimuthal Correlations in C+Ta Collisions at 4.2A GeV

    SciTech Connect (OSTI)

    Simic, Lj. [Institute of Physics, Belgrade (Serbia and Montenegro); Jotanovic, O. [Faculty of natural science, Banja Luka (Bosnia and Herzegowina)

    2007-04-23T23:59:59.000Z

    In this report we present study of two particle azimuthal correlations for protons and negative pions in 4.2A GeV C+Ta collisions. Obtained results are compared with the analysis of azimuthal distribution of particles with respect to the reaction plane.

  1. Stepping Stone Detection at The Server Side Ruei-Min Lin, Yi-Chun Chou, and Kuan-Ta Chen

    E-Print Network [OSTI]

    Chen, Sheng-Wei

    Stepping Stone Detection at The Server Side Ruei-Min Lin, Yi-Chun Chou, and Kuan-Ta Chen Institute@iis.sinica.edu.tw Abstract--Proxy server was originally invented to enhance the performance of web browsing; however, it has, there is no general method available for detecting the use of stepping stones from the server's perspective

  2. Directed-energy electron-beam processing of a hypoeutectic Cr/sub 90/Ta/sub 10/ alloy

    SciTech Connect (OSTI)

    Huang, J.S.; Kaufmann, E.N.

    1987-09-01T23:59:59.000Z

    A hypoeutectic Cr/sub 90/Ta/sub 10/ alloy was processed using a directed-energy electron-beam surface melting and resolidification technique to study its microstructure evolution during rapid solidification. The power of the electron beam was 2500 W and the scan speed ranged from 0.13 to 2.0 m/sec. Microstructure characteristics such as transitions from planar front to dendritic growth, and from cellular to dendritic growth were observed. At low solidification rate, the interdendritic regions are characterized by the Cr/Cr/sub 2/Ta eutectic, and at high solidification rate the intercellular regions are characterized by a Cr/sub 2/Ta phase. For the latter, the distribution of Ta-solute across the interior of a cell is very uniform. In a given sample, the primary cell spacing increases as the solidification front moves from the substrate/regrowth interface toward the surface. The solidification parameters, i.e., temperature gradient and growth velocity, were determined with finite-element heat flow analyses. The observed microstructure characteristics were correlated to these parameters using available theoretical models. 9 refs., 11 figs., 1 tab.

  3. Printing and Scanning Instructions Printing on Savin (reserved for Job Market/RA/TA print jobs ONLY)

    E-Print Network [OSTI]

    Niebur, Ernst

    1 Printing and Scanning Instructions Printing on Savin (reserved for Job Market/RA/TA print jobs, stapling, or three holes punch, you can find them under the "Layout" tab and "Advanced". #12;2 Scanning on Savin (NOTE: scanning is Free of Charge) A feature of the new copier is the option of using it to scan

  4. Network structure and dynamics of hydrogenated amorphous silicon D.A. Drabold *, T.A. Abtew, F. Inam, Y. Pan

    E-Print Network [OSTI]

    Drabold, David

    upon reasonable calculations of the electron-lattice coupling and molecular dynamic simulationNetwork structure and dynamics of hydrogenated amorphous silicon D.A. Drabold *, T.A. Abtew, F on the network or lattice dynamics of the system, both in the electronic ground state and in an electronic

  5. Application of cluster-plus-glue-atom model to barrierless Cu–Ni–Ti and Cu–Ni–Ta films

    SciTech Connect (OSTI)

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

    2014-11-01T23:59:59.000Z

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

  6. PROTON SPIN-LATTICE RELAXATION TIME IN THE SUPERCONDUCTING INTERCALATION COMPLEX TaS2(PYRIDINE)1/2

    E-Print Network [OSTI]

    Boyer, Edmond

    L-243 PROTON SPIN-LATTICE RELAXATION TIME IN THE SUPERCONDUCTING INTERCALATION COMPLEX TaS2 bands and superconductivity, and greatly increases the already pronounced anisotropy of the host feature of superconductivity in these complexes is that Tc is strongly affected by the intercalation

  7. A study on in situ growth of TaC whiskers in Al{sub 2}O{sub 3} matrix powder for ceramic cutting tools

    SciTech Connect (OSTI)

    Zhao, Guolong [Centre for Advanced Jet Engineering Technologies (CaJET), School of Mechanical Engineering, Shandong University, Jinan 250061 (China) [Centre for Advanced Jet Engineering Technologies (CaJET), School of Mechanical Engineering, Shandong University, Jinan 250061 (China); Key Laboratory of High-efficiency and Clean Mechanical Manufacture (Shandong University), Ministry of Education (China); Huang, Chuanzhen, E-mail: chuanzhenh@sdu.edu.cn [Centre for Advanced Jet Engineering Technologies (CaJET), School of Mechanical Engineering, Shandong University, Jinan 250061 (China) [Centre for Advanced Jet Engineering Technologies (CaJET), School of Mechanical Engineering, Shandong University, Jinan 250061 (China); Key Laboratory of High-efficiency and Clean Mechanical Manufacture (Shandong University), Ministry of Education (China); Liu, Hanlian; Xu, Liang; Chong, Xuewen; Zou, Bin; Zhu, Hongtao [Centre for Advanced Jet Engineering Technologies (CaJET), School of Mechanical Engineering, Shandong University, Jinan 250061 (China) [Centre for Advanced Jet Engineering Technologies (CaJET), School of Mechanical Engineering, Shandong University, Jinan 250061 (China); Key Laboratory of High-efficiency and Clean Mechanical Manufacture (Shandong University), Ministry of Education (China)

    2012-08-15T23:59:59.000Z

    Graphical abstract: In situ growth of TaC whiskers (TaC{sub w}) was synthesized in an ?-Al{sub 2}O{sub 3} matrix powder via a carbothermal reduction technique. The whiskers were 0.2–0.5 ?m in diameter and 5–15 ?m in length; they were straight and had smooth surfaces. Highlights: ? In situ growth of TaC whiskers was synthesized in an ?-Al{sub 2}O{sub 3} matrix powder. ? The wet mixing method and 1450 °C were suitable for whiskers growth. ? The growth of TaC whiskers is not influenced by the Al{sub 2}O{sub 3} powder. ? The major impurities were TaC particles, nickel and unreacted carbon. -- Abstract: In situ growth of tantalum carbide (TaC) whiskers was synthesized in an ?-Al{sub 2}O{sub 3} matrix powder via a carbothermal reduction technique within a temperature range of 1350–1500 °C in an argon atmosphere. The starting materials consisted of Ta{sub 2}O{sub 5}, C, Ni and NaCl powders. Different mixing methods and various reaction temperatures were employed. Most of the prepared whiskers were 0.2–0.5 ?m in diameter and 5–15 ?m in length. The reaction temperature of 1400–1450 °C was suitable for the growth of TaC whiskers and a wet mixing method was beneficial to increase the whisker yield. Some of the whiskers exhibited the needle shape while others exhibited the screw shape. The growth mechanism of the whiskers was a complex mechanism involving a helical screw dislocation mechanism and a vapor–liquid–solid process. No obvious influences of the Al{sub 2}O{sub 3} matrix powder on the growth of TaC whiskers were found and the major impurities in the obtained powder were TaC particles, nickel and unreacted carbon.

  8. The BridgeDb framework: standardized access to gene, protein and metabolite identifier mapping services

    E-Print Network [OSTI]

    2010-01-01T23:59:59.000Z

    addition to the Java API, we provide a REST-based interface.REST) and is suitable for all other programming languages. BridgeDb Java APIAPI. IH improved the Ensembl ETL process and developed the REST

  9. IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 17, NO. 2, JUNE 2007 271 Utilizing Nonlinearity in a Superconducting NbN

    E-Print Network [OSTI]

    Buks, Eyal

    Nonlinearity in a Superconducting NbN Stripline Resonator for Radiation Detection Eran Segev, Baleegh Abdo-FAST and sensitive radiation detection is a key enabling element in various fields of research

  10. Studies of Nb3Sn Strands Based on the Restacked-Rod Process for High-Field Accelerator Magnets Nb3Sn

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Barzi, E; Bossert, M; Gallo, G; Lombardo, V; Turrioni, D; Yamada, R; Zlobin, A V

    2012-06-01T23:59:59.000Z

    A major thrust in Fermilab's accelerator magnet R&D program is the development of Nb3Sn wires which meet target requirements for high field magnets, such as high critical current density, low effective filament size, and the capability to withstand the cabling process. The performance of a number of strands with 150/169 restack design produced by Oxford Superconducting Technology was studied for round and deformed wires. To optimize the maximum plastic strain, finite element modeling was also used as an aid in the design. Results of mechanical, transport and metallographic analyses are presented for round and deformed wires.

  11. Superconductivity in bulk A15 Nb/sub 3/Si under pressure

    SciTech Connect (OSTI)

    Lim, K.C.; Thompson, J.D.; Olinger, B.; Newkirk, L.R.

    1981-12-01T23:59:59.000Z

    We have determined the effect of hydrostatic pressure P on the superconducting transition temperature T/sub c/ of bulk, A15 Nb/sub 3/Si. For 0< or =P< or =20 kbar (2 GPa), T/sub c/ decrease linearly with increasing pressure at the rate partialP/sub c//partialP = -2.67 x 10/sup -5/ K/bar. From an estimate of partialT/sub c//partialP obtained using recent band structure calculations for the density-of-electronic-states change as a function of lattice parameter in Nb/sub 3/Si, we conclude that the pressure dependence of the electron-phonon interaction primarily determines partialT/sub c//partialP.

  12. Permeability of CoNbZr amorphous thin films over a wide frequency range

    SciTech Connect (OSTI)

    Koyama, H.; Tsujimoto, H.; Shirae, K.

    1987-09-01T23:59:59.000Z

    CoNbZr amorphous films have attracted the attention of many researchers because of their high saturation magnetization, high permeability, low coercivity, and nearly zero magnetostriction. For these films to be used, one of the important magnetic properties is the behavior of the permeability over a wide frequency range. We have measured the permeability of a square-shaped magnetic film (13 mm x 55 mm) sputtered on a glass substrate from 1 MHz to 400 MHz using a stripline. Over 400 MHz, the permeability of the magnetic film was measured using a ring-shaped sample mounted in a coaxial fixture. The wall motion permeability of CoNbZr amorphous films decreases from 1 kHz to nearly zero at 1 MHz. The rotation permeability is constant to 100 MHz and ferromagnetic resonance is observed near 1 GHz.

  13. Effects of Natural Aging on the Tensile Properties of Water-Quenched U-6% Nb Alloy

    SciTech Connect (OSTI)

    Sunwoo, A J; Hiromoto, D S

    2003-12-09T23:59:59.000Z

    Uranium-6 wt-% niobium (U-6% Nb) alloy has been in use for many years in the water-quenched (WQ) condition. The purpose of this work was to determine the effect of natural aging on tensile properties of the WQ U-6% Nb alloy. The materials studied were hemispherical shells after 15 and 20 years in storage. The alloy was successfully tested in the original curved configuration, using the specially designed tensile test apparatus. Finite element analysis confirmed the validity of the test method. The results of the tensile tests clearly indicated that in the WQ condition, the material is changing and after 15 and 20 years, the yield strength exceeds the original maximum allowable specification. The fracture mode transitions from highly ductile, microvoid coalescence in new material to a mixed mode of shallow dimples and inclusion-induced voids in the naturally aged material.

  14. High-Temperature Heat Treatment Study on a Large-Grain Nb Cavity

    SciTech Connect (OSTI)

    G. Ciovati, P. Dhakal, R. Myneni, P. Maheshwari, F.A. Stevie

    2011-07-01T23:59:59.000Z

    Improvement of the cavity performance by a high-temperature heat-treatment without subsequent chemical etching have been reported for large-grain Nb cavities treated by buffered chemical polishing, as well as for a fine-grain cavity treated by vertical electropolishing. Changes in the quality factor, Q{sub 0}, and maximum peak surface magnetic field achieved in a large-grain Nb single-cell cavity have been determined as a function of the heat treatment temperature, between 600 °C and 1200 °C. The highest Q{sub 0} improvement of about 30% was obtained after heat-treatment at 800 °C-1000 °C. Measurements by secondary ion mass spectrometry on large-grain samples heat-treated with the cavity showed large reduction of hydrogen concentration after heat treatment.

  15. Test of a NbTi Superconducting Quadrupole Magnet Based on Alternating Helical Windings

    SciTech Connect (OSTI)

    Caspi, S.; Trillaud, F.; Godeke, A.; Dietderich, D.; Ferracin, P.; Sabbi, G.; Giloux, C.; Perez, J. G.; Karppinen, M.

    2009-08-16T23:59:59.000Z

    It has been shown that by superposing two solenoid-like thin windings, that are oppositely skewed (tilted) with respect to the bore axis, the combined current density on the surface is cos({theta})-like and the resulting magnetic field in the bore is a pure dipole field. Following a previous test of such a superconducting dipole magnet, a quadrupole magnet was designed and built using similar principles. This paper describes the design, construction and test of a 75 mm bore 600 mm long superconducting quadrupole made with NbTi wire. The simplicity of the design, void of typical wedges, end-spacers and coil assembly, is especially suitable for future high field insert coils using Nb{sub 3}Sn as well as HTS wires. The 3 mm thick coil reached 46 T/m but did not achieve its current plateau.

  16. Development of a Large Aperture Nb3Sn Racetrack Quadrupole Magnet

    SciTech Connect (OSTI)

    Ferracin, Paolo; Bartlett, Scott E.; Caspi, Shlomo; Dietderich, Daniel R.; Gourlay, Steve A.; Hannaford, Charles R.; Hafalia, Aurelio R.; Lietzke, Alan F.; Mattafirri, Sara; McInturff, Alfred D.; Nyman, Mark; Sabbi, Gianluca

    2005-06-01T23:59:59.000Z

    The U.S. LHC Accelerator Research Program (LARP), a collaboration between BNL, FNAL, LBNL, and SLAC, has among its major objectives the development of advanced magnet technology for an LHC luminosity upgrade. The LBNL Superconducting Magnet Group supports this program with a broad effort involving design studies, Nb{sub 3}Sn conductor development, mechanical models, and basic prototypes. This paper describes the development of a large aperture Nb{sub 3}Sn racetrack quadrupole magnet using four racetrack coils from the LBNL Subscale Magnet (SM) Program. The magnet provides a gradient of 95 T/m in a 110 mm bore, with a peak field in the conductor of 11.2 T. The coils are pre-stressed by a mechanical structure based on a pre-tensioned aluminum shell, and axially supported with aluminum rods. The mechanical behavior has been monitored with strain gauges and the magnetic field has been measured. Results of the test are reported and analyzed.

  17. Correlation and comparison of Nb/sub 2/ lymphoma cell bioassay with radioimmunoassay for human prolactin

    SciTech Connect (OSTI)

    Subramanian, M.G.; Spirtos, N.J.; Moghissi, K.S.; Magyar, D.M.; Hayes, M.F.; Gala, R.R.

    1984-12-01T23:59:59.000Z

    Serum samples from groups of men and women with normal and elevated prolactin (PRL) levels were assayed by radioimmunoassay (RIA) and by Nb/sub 2/ lymphoma cell bioassay (BA) for the presence of PRL. Because the Nb/sub 2/ lymphoma cells respond to both PRL and growth hormone, BA for PRL activity was carried out before and after neutralization of growth hormone in the serum samples. There were excellent correlations between RIA and BA both in euprolactinemic and hyperprolactinemic subjects. On an absolute basis, RIA and BA values were similar in the euprolactinemic group (6.6 +/- 0.8 versus 6.2 +/- 1.0), whereas in the hyperprolactinemic group, RIA values were significantly higher than the BA results. The two assay systems also appeared to correlate better in women who were hyperprolactinemic, with obvious menstrual cycle disturbances, than in hyperprolactinemic women without menstrual cycle disturbances.

  18. Physical and mechanical metallurgy of high purity Nb for accelerator cavities

    SciTech Connect (OSTI)

    Bieler, T. R. [Michigan State University, East Lansing; Wright, N. T. [Michigan State University, East Lansing; Pourboghrat, F. [Michigan State University, East Lansing; Compton, C. [Michigan State University, East Lansing; Hartwig, K. T. [Texas A& M University; Baars, D. [Michigan State University, East Lansing; Zamiri, A. [Michigan State University, East Lansing; Chandrasekaran, S. [Michigan State University, East Lansing; Darbandi, P. [Michigan State University, East Lansing; Jiang, H. [Michigan State University, East Lansing; Skoug, E. [Michigan State University, East Lansing; Balachandran, S. [Texas A& M University; Ice, Gene E [ORNL; Liu, W. [Argonne National Laboratory (ANL)

    2010-01-01T23:59:59.000Z

    In the past decade, high Q values have been achieved in high purity Nb superconducting radio frequency (SRF) cavities. Fundamental understanding of the physical metallurgy of Nb that enables these achievements is beginning to reveal what challenges remain to establish reproducible and cost-effective production of high performance SRF cavities. Recent studies of dislocation substructure development and effects of recrystallization arising from welding and heat treatments and their correlations with cavity performance are considered. With better fundamental understanding of the effects of dislocation substructure evolution and recrystallization on electron and phonon conduction, as well as the interior and surface states, it will be possible to design optimal processing paths for cost-effective performance using approaches such as hydroforming, which minimizes or eliminates welds in a cavity.

  19. Infrared Transmissometer to Measure the Thickness of NbN Thin Films

    E-Print Network [OSTI]

    Sunter, Kristen A; Lang, Christopher I; Berggren, Karl K

    2015-01-01T23:59:59.000Z

    We present an optical setup that can be used to characterize the thicknesses of thin NbN films to screen samples for fabrication and to better model the performance of the resulting superconducting nanowire single photon detectors. The infrared transmissometer reported here is easy to use, gives results within minutes and is non-destructive. Thus, the thickness measurement can be easily integrated into the workflow of deposition and characterization. Comparison to a similar visible-wavelength transmissometer is provided.

  20. Understanding the origin of high-rate intercalation pseudocapacitance in Nb2O5 crystals

    SciTech Connect (OSTI)

    Ganesh, Panchapakesan [ORNL] [ORNL; Kent, P. R. C. [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK); Sumpter, Bobby G [ORNL] [ORNL; Lubimtsev, Andrew A [ORNL] [ORNL

    2013-01-01T23:59:59.000Z

    Pseudocapacitors aim to maintain the high power density of supercapacitors while increasing the energy density towards those of energy dense storage systems such as lithium ion batteries. Recently discovered intercalation pseudocapacitors (e.g. Nb2O5) are particularly interesting because their performance is seemingly not limited by surface reactions or structures, but instead determined by the bulk crystalline structure of the material. We study ordered polymorphs of Nb2O5 and detail the mechanism for the intrinsic high rates and energy density observed for this class of materials. We find that the intercalating atom (lithium) forms a solid solution adsorbing at specific sites in a network of quasi-2D NbOx faces with x {1.3, 1.67, or 2}, donating electrons locally to its neighboring atoms, reducing niobium. Open channels in the structure have low diffusion barriers for ions to migrate between these sites (Eb 0.28 0.44 eV) comparable to high-performance solid electrolytes. Using a combination of complementary theoretical methods we rationalize this effect in LixNb2O5 for a wide range of compositions (x) and at finite temperatures. Multiple adsorption sites per unit-cell with similar adsorption energies and local charge transfer result in high capacity and energy density, while the interconnected open channels lead to low cost diffusion pathways between these sites, resulting in high power density. The nano-porous structure exhibiting local chemistry in a crystalline framework is the origin of high-rate pseudocapacitance in this new class of intercalation pseudocapacitor materials. This new insight provides guidance for improving the performance of this family of materials.

  1. Studies of Optical Damage in Photorefractive Single LiNbO3 Crystals using Imaging Polarimetry

    E-Print Network [OSTI]

    O. Krupych; I. Smaga; R. Vlokh

    2007-08-15T23:59:59.000Z

    The optical damage of photorefractive material, single LiNbO3 crystal, is experimentally studied. The specimen has been illuminated with the radiation of continuous Ar-laser (the wavelength of 488 nm) focused to 35?m spot. The induced birefringence map is obtained by means of imaging polarimeter. Promising resources of the experimental setup for detecting laser-induced damage in photorefractive materials is demonstrated.

  2. DESIGN, FABRICATION AND TEST OF THE REACT AND WIND, NB(3)SN, LDX FLOATING COIL CONDUCTOR.

    SciTech Connect (OSTI)

    SMITH,B.A.; MICHAEL,P.C.; MINERVINI,J.V.; TAKAYASU,M.; SCHULTZ,J.H.; GREGORY,E.; PYON,T.; SAMPSON,W.B.; GHOSH,A.; SCANLAN,R.

    2000-09-17T23:59:59.000Z

    The Levitated Dipole Experiment (LDX) is a novel approach for studying magnetic confinement of a fusion plasma. In this approach, a superconducting ring coil is magnetically levitated for up to 8 hours a day in the center of a 5 meter diameter vacuum vessel. The levitated coil, with on-board helium supply, is called the gloating Coil (F-Coil). Although the maximum field at the coil is only 5.3 tesla, a react-and-wind Nb{sub 3}Sn conductor was selected because the relatively high critical temperature will enable the coil to remain levitated while it warms from 5 K to 10 K. Since pre-reacted Nb{sub 3}Sn tape is no longer commercially available, a composite conductor was designed that contains an 18 strand Nb{sub 3}Sn Rutherford cable. The cable was reacted and then soldered into a structural copper channel that completes the conductor and also provides quench protection. The strain state of the cable was continuously controlled during fabrication steps such as: soldering into the copper channel, spooling, and coil winding, to prevent degradation of the critical current. Measurements of strand and cable critical currents are reported, as well as estimates of the effect of fabrication, winding and operating strains on critical current.

  3. Increasing the Jc of Tube-Type Nb3Sn Strands

    SciTech Connect (OSTI)

    Dr. Xuan Peng

    2012-12-17T23:59:59.000Z

    In this Phase I, we successfully made strands with better Cu/Sn ratio to reduce the coarse Nb3Sn grain region, thereby providing the potential of increasing the non-Cu Jc in the Phase II and scaling up to 2�¢��� billets with 331 subelements. In order to improve the strand�¢����s high field properties, we successfully doped low amount of Ti in the subelements and made a 217-subelement wire which has been drawn down to 0.7 mm without any breakage. This strand gave subelement size of 35 ���µm. We will scale up the Ti-doped billet to 271-subelement in 1.5�¢��� billet in this proposed Phase II. The hexagonal shaped subelements with round Nb-Sn have been developed for a 61-subelement restack. Thus the results indicated that for 217-subelement restack in a 2�¢��� billet we have the potential to draw down this type of construction without problems while maintaining a good array to react more Nb to get higher non-Cu Jc in the Phase II.

  4. Investigation of the sup 9 sup 3 Nb neutron cross-sections in resonance energy range

    E-Print Network [OSTI]

    Grigoriev, Y V; Faikov-Stanchik, H; Ilchev, G; Kim, G N; Kitaev, V Ya; Mezentseva, Z V; Panteleev, T; Sinitsa, V V; Zhuravlev, B V

    2001-01-01T23:59:59.000Z

    The results of gamma-ray multiplicity spectra and transmission measurements for sup 9 sup 3 Nb in energy range 21.5 eV-100 keV are presented. Gamma spectra from 1 to 7 multiplicity were measured on the 501 m and 121 m flight paths of the IBR-30 using a 16-section scintillation detector with a NaI(Tl) crystals of a total volume of 36 l and a 16-section liquid scintillation detector of a total volume of 80 l for metallic samples of 50, 80 mm in diameter and 1, 1.5 mm thickness with 100% sup 9 sup 3 Nb. Besides, the total and scattering cross-section of sup 9 sup 3 Nb were measured by means batteries of B-10 and He-3 counters on the 124 m, 504 m and 1006 m flight paths of the IBR-30. Spectra of multiplicity distribution were obtained for resolved resonances in the energy region E=30-6000 eV and for energy groups in the energy region E=21.5 eV- 100 keV. They were used for determination of the average multiplicity, resonance parameters and capture cross-section in energy groups and for low-laying resonances of sup...

  5. Elastic-Plastic Behavior of U6Nb under Ramp Wave Loading

    SciTech Connect (OSTI)

    Hayes, D. B.; Gray, G. T. III; Hixson, R. S. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Hall, C. A. [Sandia National Laboratories, Albuquerque New Mexico 87185-1181 (United States)

    2006-07-28T23:59:59.000Z

    When uranium-niobium (6 wt.%) alloy is shock loaded, the expected elastic precursor is absent. A prior model attributed this absence to shear-induced twinning and the concomitant shear stress reduction that prevented the shocked material from reaching the plastic yield point. In the present study, carefully prepared U6Nb was subjected to shock loading to verify the adequacy of the prior model. Other samples were loaded with a ramp pressure pulse with strain rate large enough so that significant twinning would not occur during the experiment. Backward integration analyses of these latter experiments' back surface motion give stress-strain loading paths in U6Nb that suggest ordinary elastic-plastic flow. Some of the U6Nb was pre-strained by cold rolling in an effort to further ensure that twinning did not affect wave propagation. Shock and ramp loadings yielded similar results to the baseline material except, as expected, they are consistent with a higher yield stress and twinning shear stress threshold.

  6. Aluminum Stabilized NbTi Conductor Test Coil Design, Fabrication, and Test Results

    SciTech Connect (OSTI)

    Andreev, N.; Chlachidze, G.; Evbota, D.; Kashikhin, V.S.; Lamm, M.; Makarov, A.; Tartaglia, M.; /Fermilab; Nakamoto, T.; Ogitsu, T.; Tanaka, K.; Yamamoto, A.; /KEK, Tsukuba

    2011-09-01T23:59:59.000Z

    A new generation of precision muon conversion experiments is planned at both Fermilab and KEK. These experiments will depend upon a complex set of solenoid magnets for the production, momentum selection and transport of a muon beam to a stopping target, and for tracking detector momentum analysis of candidate conversion electrons from the target. Baseline designs for the production and detector solenoids use NbTi cable that is heavily stabilized by an extruded high RRR aluminum jacket. A U.S.-Japan research collaboration has begun whose goal is to advance the development of optimized Al-NbTi conductors, gain experience with the technology of winding coils from this material, and test the conductor performance as modest length samples become available. For this purpose, a 'conductor test' solenoid with three coils was designed and built at Fermilab. A sample of the RIKEN Al-NbTi conductor from KEK was wound into a 'test' coil; this was sandwiched between two 'field' coils wound from doubled SSC cable, to increase the peak field on the RIKEN test coil. All three solenoid coils were epoxy impregnated, and utilized aluminum outer bandage rings to apply preload to the coils when cold. The design and fabrication details, and results of the magnet quench performance tests are presented and discussed.

  7. Development and Coil Fabrication for the LARP 3.7-m Long Nb3Sn Quadrupole

    SciTech Connect (OSTI)

    Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Chlachidize, G.; Dietderich, D.; Felice, H.; Ferracin, P.; Ghosh, A.; Hafalia, R.; Hannaford, R.; Jochen, G.; Kashikhin, V.V.; Kovach, P.; Lamm, M.; Lietzke, A.; McInturff, A.; Muratore,, J.; Nobreaga, F.; Novitsky, I.; Peggs, S.; Prestemon, S.; Sabbi, G. L.; Schmalzle, J.; Turrioni, D.; Wanderer, P.; Whitson, G.; Zlobin, A. V.

    2008-08-17T23:59:59.000Z

    The U.S. LHC Accelerator Research Program (LARP) has started the fabrication of 3.7-m long Nb{sub 3}Sn quadrupole models. The Long Quadrupoles (LQ) are 'Proof-of-Principle' magnets which are to demonstrate that Nb{sub 3}Sn technology is mature for use in high energy particle accelerators. Their design is based on the LARP Technological Quadrupole (TQ) models, developed at FNAL and LBNL, which have design gradients higher than 200 T/m and an aperture of 90 mm. The plans for the LQ R&D and a design update are presented and discussed in this paper. The challenges of fabricating long accelerator-quality Nb{sub 3}Sn coils are presented together with the solutions adopted for the LQ coils (based on the TQ experience). During the fabrication and inspection of practice coils some problems were found and corrected. The fabrication at BNL and FNAL of the set of coils for the first Long Quadrupole is in progress.

  8. Development and coil fabrication for the LARP 3.7-m long Nb3Sn quadruple

    SciTech Connect (OSTI)

    Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Chlachidize, G.; Dietderich, D.; Felice, H.; Ferracin, P.; Ghosh, A.; /Fermilab /Brookhaven /LBL, Berkeley /Texas A-M

    2009-02-01T23:59:59.000Z

    The U.S. LHC Accelerator Research Program (LARP) has started the fabrication of 3.7-m long Nb{sub 3}Sn quadrupole models. The Long Quadrupoles (LQ) are 'Proof-of-Principle' magnets which are to demonstrate that Nb3Sn technology is mature for use in high energy particle accelerators. Their design is based on the LARP Technological Quadrupole (TQ) models, developed at FNAL and LBNL, which have design gradients higher than 200 T/m and an aperture of 90 mm. The plans for the LQ R&D and a design update are presented and discussed in this paper. The challenges of fabricating long accelerator-quality Nb{sub 3}Sn coils are presented together with the solutions adopted for the LQ coils (based on the TQ experience). During the fabrication and inspection of practice coils some problems were found and corrected. The fabrication at BNL and FNAL of the set of coils for the first Long Quadrupole is in progress.

  9. Fabrication of a Short-Period Nb3Sn Superconducting Undulator

    SciTech Connect (OSTI)

    Dietderich, Daniel; Dietderich, Daniel; Godeke, Arno; Prestemon, Soren; Pipersky, Paul T.; Liggins, Nate L.; Higley, Hugh C.; Marks, Steve; Schlueter, Ross D.

    2007-06-01T23:59:59.000Z

    Lawrence Berkeley National Laboratory develops high-field Nb{sub 3}Sn magnets for HEP applications. In the past few years, this experience has been extended to the design and fabrication of undulator magnets. Some undulator applications require devices that can operate in the presence of a heat load from a beam. The use of Nb{sub 3}Sn permits operation of a device at both a marginally higher temperature (5-8K) and a higher J{sub c}, compared to NbTi devices, without requiring a larger magnetic gap. A half-undulator device consisting of 6 periods (12 coil packs) of 14.5 mm period was designed, wound, reacted, potted and tested. It reached the short sample current limit of 717A in 4 quenches. The non-Cu Jc of the strand was over 7,600 A/mm{sup 2} and the Cu current density at quench was over 8,000 A/mm{sup 2}. Magnetic field models show that if a complete device was fabricated with the same parameters one could obtain beam fields of 1.1 T and 1.6 T for pole gaps of 8 mm and 6 mm, respectively.

  10. Understanding Irreversible Degradation of Nb3Sn Wires with Fundamental Fracture Mechanics

    SciTech Connect (OSTI)

    Zhai, Yuhu [PPPL; Calzolaio, Ciro [Univ of Geneva; Senatore, Carmine [Univ of Geneva

    2014-08-01T23:59:59.000Z

    Irreversible performance degradation of advanced Nb3Sn superconducting wires subjected to transverse or axial mechanical loading is a critical issue for the design of large-scale fusion and accelerator magnets such as ITER and LHC. Recent SULTAN tests indicate that most cable-in-conduit conductors for ITER coils made of Nb3Sn wires processed by various fabrication techniques show similar performance degradation under cyclic loading. The irreversible degradation due to filament fracture and local strain accumulation in Nb3Sn wires cannot be described by the existing strand scaling law. Fracture mechanic modeling combined with X-ray diffraction imaging of filament micro-crack formation inside the wires under mechanical loading may reveal exciting insights to the wire degradation mechanisms. We apply fundamental fracture mechanics with a singularity approach to study influence of wire filament microstructure of initial void size and distribution to local stress concentration and potential crack propagation. We report impact of the scale and density of the void structure on stress concentration in the composite wire materials for crack initiation. These initial defects result in an irreversible degradation of the critical current beyond certain applied stress. We also discuss options to minimize stress concentration in the design of the material microstructure for enhanced wire performance for future applications.

  11. Study of possible systematics in the L*X - Ta* correlation of Gamma Ray Bursts

    E-Print Network [OSTI]

    M. G. Dainotti; V. F. Cardone; S. Capozziello; M. Ostrowski; R. Willingale

    2011-01-09T23:59:59.000Z

    Gamma Ray Bursts (GRBs) are the most energetic sources in the universe and among the farthest known astrophysical sources. These features make them appealing candidates as standard candles for cosmological applications so that studying the physical mechanisms for the origin of the emission and correlations among their observable properties is an interesting task. We consider here the luminosity L*X - break time Ta* (hereafter LT) correlation and investigate whether there are systematics induced by selection effects or redshift dependent calibra- tion. We perform this analysis both for the full sample of 77 GRBs with known redshift and for the subsample of GRBs having canonical X-ray light curves, hereafter called U0095 sample. We do not find any systematic bias thus con- firming the existence of physical GRB subclasses revealed by tight correlations of their afterglow properties. Furthermore, we study the possibility of applying the LT correlation as a redshift estimator both for the full distribution and for the canonical lightcurves. The large uncertainties and the non negligible intrin- sic scatter make the results not so encouraging, but there are nevertheless some hints motivating a further analysis with an increased U0095 sample.

  12. A Quasicontinuum Study of Nanovoid Collapse under Uniaxial Loading in Ta

    SciTech Connect (OSTI)

    Marian, J; Knap, J; Campbell, G

    2007-12-02T23:59:59.000Z

    The mechanisms underlying the deformation of nanovoids in Ta single crystals are analyzed when they are subjected to cyclic uniaxial deformation using numerical simulations. Boundary and cell-size effects have been mitigated by means of the Quasicontinuum (QC) method. We have considered {approx} 1 billion-atom systems containing 10.9 nm voids. Two kinds of simulations have been performed, each characterized by a different boundary condition. First, we compress the material along the nominal [0 0 1] direction, resulting in a highly symmetric configuration that results in high stresses. Second, we load the material along the high-index [{bar 4}819] direction to confine plasticity to a single slip system and break the symmetry. We find that the plastic response under these two conditions is strikingly different, the former governed by dislocation loop emission and dipole formation, while the latter is dominated by twinning. We calculate the irreversible plastic work budget derived from a loading-unloading cycle and identify the most relevant yield points. These calculations represent the first fully three-dimensional, fully non-local simulations of any body-centered cubic metal using QC.

  13. The effect of Ta doping in polycrystalline TiO{sub x} and the associated thin film transistor properties

    SciTech Connect (OSTI)

    Ok, Kyung-Chul, E-mail: kchul2926@naver.com; Park, Yoseb, E-mail: jozeph.park@gmail.com; Park, Jin-Seong, E-mail: kbchung@dankook.ac.kr, E-mail: jsparklime@hanyang.ac.kr [Division of Materials Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of)] [Division of Materials Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Chung, Kwun-Bum, E-mail: kbchung@dankook.ac.kr, E-mail: jsparklime@hanyang.ac.kr [Department of Physics, Dankook University, 119 Dandae-ro, Dongnam-gu, Cheonan 330-714 (Korea, Republic of)] [Department of Physics, Dankook University, 119 Dandae-ro, Dongnam-gu, Cheonan 330-714 (Korea, Republic of)

    2013-11-18T23:59:59.000Z

    Tantalum (Ta) is suggested to act as an electron donor and crystal phase stabilizer in titanium oxide (TiO{sub x}). A transition occurs from an amorphous state to a crystalline phase at an annealing temperature above 300?°C in a vacuum ambient. As the annealing temperature increases from 300?°C to 450?°C, the mobility increases drastically from 0.07 cm{sup 2}/Vs to 0.61 cm{sup 2}/Vs. The remarkable enhancement of thin film transistor performance is suggested to be due to the splitting of Ti 3d band orbitals as well as the increase in Ta{sup 5+} ions that can act as electron donors.

  14. Floodplain Assessment for the Proposed Outdoor Fire Range Upgrades at TA-72 in Lower Sandia Canyon, Los Alamos National Laboratory

    SciTech Connect (OSTI)

    Hathcock, Charles D. [Los Alamos National Laboratory

    2012-08-27T23:59:59.000Z

    Los Alamos National Laboratory (LANL) is preparing to implement actions in Sandia Canyon at Technical Area (TA) 72. Los Alamos National Security (LANS) biologists conducted a floodplain determination and this project is partially located within a 100-year floodplain. The proposed project is to upgrade the existing outdoor shooting range facilities at TA-72. These upgrades will result in increased safety and efficiencies in the training for Protective Force personnel. In order to remain current on training requirements, the firing ranges at TA-72 will be upgraded which will result in increased safety and efficiencies in the training for Protective Force personnel (Figure 1). These upgrades will allow for an increase in class size and more people to be qualified at the ranges. Some of these upgrades will be built within the 100-year floodplain. The upgrades include: concrete pads for turning target systems and shooting positions, new lighting to illuminate the firing range for night fire, a new speaker system for range operations, canopies at two locations, an impact berm at the far end of the 300-yard mark, and a block wall for road protection.

  15. Selective etching of TiN over TaN and vice versa in chlorine-containing plasmas

    SciTech Connect (OSTI)

    Shin, Hyungjoo; Zhu Weiye; Liu Lei; Sridhar, Shyam; Donnelly, Vincent M.; Economou, Demetre J. [Plasma Processing Laboratory, Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004 (United States); Lenox, Chet; Lii, Tom [Texas Instruments Inc., Dallas, Texas 75243 (United States)

    2013-05-15T23:59:59.000Z

    Selectivity of etching between physical vapor-deposited TiN and TaN was studied in chlorine-containing plasmas, under isotropic etching conditions. Etching rates for blanket films were measured in-situ using optical emission of the N{sub 2} (C{sup 3}{Pi}{sub u}{yields}B{sup 3}{Pi}{sub g}) bandhead at 337 nm to determine the etching time, and transmission electron microscopy to determine the starting film thickness. The etching selectivity in Cl{sub 2}/He or HCl/He plasmas was poor (<2:1). There was a window of very high selectivity of etching TiN over TaN by adding small amounts (<1%) of O{sub 2} in the Cl{sub 2}/He plasma. Reverse selectivity (10:1 of TaN etching over TiN) was observed when adding small amounts of O{sub 2} to the HCl/He plasma. Results are explained on the basis of the volatility of plausible reaction products.

  16. A Leader-Follower Algorithm for Multiple AUV Formations D. B. Edwards, T.A. Bean, *D.L. Odell, M.J. Anderson

    E-Print Network [OSTI]

    Idaho, University of

    A Leader-Follower Algorithm for Multiple AUV Formations D. B. Edwards, T.A. Bean, *D.L. Odell, M.5 million square meters of shallow water for mines in Operation Enduring Freedom in Iraq 2003 [1

  17. Proposal for the award of a contract for the supply of Nb3Sn superconducting wire for the 11 T project at CERN

    E-Print Network [OSTI]

    2015-01-01T23:59:59.000Z

    Proposal for the award of a contract for the supply of Nb3Sn superconducting wire for the 11 T project at CERN

  18. Proposal to negotiate a collaboration agreement for R&D activities relating to Nb3Sn superconducting wire for the High Luminosity LHC project

    E-Print Network [OSTI]

    2015-01-01T23:59:59.000Z

    Proposal to negotiate a collaboration agreement for R&D activities relating to Nb3Sn superconducting wire for the High Luminosity LHC project

  19. Proposal for the award of a contract for the supply of Nb3Sn superconducting wire for the MQXF project at CERN

    E-Print Network [OSTI]

    2015-01-01T23:59:59.000Z

    Proposal for the award of a contract for the supply of Nb3Sn superconducting wire for the MQXF project at CERN

  20. Effects of Nb-doped on the structure and electrochemical performance of LiFePO{sub 4}/C composites

    SciTech Connect (OSTI)

    Ma, Zhipeng [Hebei Key Laboratory of Applied Chemistry, College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004 (China); Shao, Guangjie, E-mail: shaoguangjie@ysu.edu.cn [Hebei Key Laboratory of Applied Chemistry, College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004 (China); State Key Laboratory of Metastable Materials Science and Technology, Qinhuangdao 066004 (China); Wang, Guiling; Zhang, Ying; Du, Jianping [Hebei Key Laboratory of Applied Chemistry, College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004 (China)

    2014-02-15T23:59:59.000Z

    The olivine-type niobium doping Li{sub 1?x}Nb{sub x}FePO{sub 4}/C (x=0, 0.005, 0.010, 0.015, 0.025) cathode materials were synthesized via a two-step ball milling solid state reaction. The effects of Nb doping were charactered by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), galvanostatic intermittent titration technique (GITT), cyclic voltammetry (CV), electrochemical impedance spectra (EIS) and galvanostatic charge–discharge. It is found that Nb doping enlarges the interplanar distance of crystal plane parallel to [0 1 0] direction in LiFePO{sub 4}. In other words, it widens the one dimensional diffusion channels of Li{sup +} along the [0 1 0] direction. Electrochemical test results indicate that the Li{sub 0.99}Nb{sub 0.01}FePO{sub 4}/C composite exhibits the best electrochemical performance with initial special discharge capacity of 139.3 mA h g{sup ?1} at 1 C rate. The present synthesis route is promising in making the solid state reaction method more practical for preparation of the LiFePO{sub 4} material. - Graphical abstract: The proper amount of Nb doping widens the one dimensional diffusion channels of Li{sup +} along the [0 1 0] direction. Display Omitted - Highlights: • The Nb doping LiFePO{sub 4}/C is prepared by a facile two-step ball milling solid state reaction. • The sample possesses the better high-rate performance. • The tap density of Li{sub 0.99}Nb{sub 0.01}FePO{sub 4}/C sample is 1.76 g cm{sup ?3}.

  1. Radionuclide contaminant analysis of small mammals at Area G, TA-54, Los Alamos National Laboratory, 1995

    SciTech Connect (OSTI)

    Bennett, K.; Biggs, J.; Fresquez, P.

    1997-01-01T23:59:59.000Z

    At Los Alamos National Laboratory, small mammals were sampled at two waste burial sites (Site 1-recently disturbed and Site 2-partially disturbed) at Area G, Technical Area 54 and a control site on Frijoles Mesa (Site 4) in 1995. Our objectives were (1) to identify radionuclides that are present within surface and subsurface soils at waste burial sites, (2) to compare the amount of radionuclide uptake by small mammals at waste burial sites to a control site, and (3) to identify if the primary mode of contamination to small mammals is by surface contact or ingestion/inhalation. Three composite samples of at least rive animals per sample were collected at each site. Pelts and carcasses of each animal were separated and analyzed independently. Samples were analyzed for {sup 241}Am, {sup 90}Sr , {sup 238}Pu, {sup 239}Pu, total U, {sup 137}Cs, and {sup 3}H. Significantly higher (parametric West at p=0.05) levels of total U, {sup 241}Am, {sup 238}Pu and {sup 239}Pu were detected in pelts than in carcasses of small mammals at TA-54. Concentrations of other measured radionuclides in carcasses were nearly equal to or exceeded the mean concentrations in the pelts. Our results show higher concentrations in pelts compared to carcasses, which is similar to what has been found at waste burial/contaminated sites outside of Los Alamos National Laboratory. Site 1 had a significantly higher (alpha=0.05, P=0.0125) mean tritium concentration in carcasses than Site 2 or Site 4. In addition Site 1 also had a significantly higher (alpha=0.05, p=0.0024) mean tritium concentration in pelts than Site 2 or Site 4. Site 2 had a significantly higher (alpha=0.05, P=0.0499) mean {sup 239}Pu concentration in carcasses than either Site 1 or Site 4.

  2. Metastable phases determination of U-2.5Zr-7.5Nb and U-3.0Zr-9.0Nb alloys by Rietveld method

    SciTech Connect (OSTI)

    Dias Pais, R. W.; Dos Santos, A. M. M.; Lameiras, F. S.; Cantagalli, N. M.; De Paula, R. G.; Ferraz, W. B. [Centro de Desenvolvimento da Tecnologia Nuclear, CDTN, CNEN, Av. Presidente Antonio Carlos 6.627, 31270-901 - Belo Horizonte, MG (Brazil)

    2012-07-01T23:59:59.000Z

    The Rietveld refinement has been employed for study of metastable phase of alloys U-2.5Zr-7.5Nb(wt%) and U-3Zr-9Nb(wt%). The ingots of both alloys were produced in vacuum induction furnace at temperature of about 1500 deg.C followed by cooling to room temperature. The samples with 2.5 cm in diameter and 0.3 cm of thickness was homogenized at 1000 deg.C/16 hours and treated isothermally at (i) 600 deg.C for 0.5, 3 and 24 hours and (ii) 300 deg.C for 4 minutes, 20 minutes and 17.5 hours. At the end of each treatment the samples were water quenched. Data from X-ray diffraction were collected at room temperature with a Rigaku diffractometer D Max-RAPID radiation Cuk{alpha} using steps of 0.02 deg. (2{theta}) with scan angle in the range of 20-80 deg. (2{theta}). The full diffraction pattern was analyzed by the Rietveld method using the GSAS program. The result shows that the non-resolved appearance of the XRD patterns added to the proximity of the Bragg reflections of the transition phase makes the refinement of alloys a challenging task. For the isothermal treatment at 600 deg.C during 0.5 and 3 hours both alloys showed the majority presence of {gamma}{sup S} phase fallow by {gamma}{sup 0} phase in minor amounts. For 24 hours at 600 deg.C occurred the decomposition of phases with the presence of {gamma}{sup S} + {alpha}. Isothermal treatment at 300 deg.C for both alloys is characterized by the presence of phases {gamma}{sup 0} + {alpha}'' where the concentration of the {alpha}'' phase increases with time of heat treatment. (authors)

  3. Off-center displacement of the Nb ions below and above the ferroelectric phase transition of KTa sub 0. 91 Nb sub 0. 09 O sub 3

    SciTech Connect (OSTI)

    Hanske-Petitpierre, O. (Physics Department (FM-15), University of Washington, Seattle, Washington (USA)); Yacoby, Y. (Racah Institute of Physics, The Hebrew University of Jerusalem, Givat Ram, 91 904 Jerusalem (Israel)); Mustre de Leon, J.; Stern, E.A.; Rehr, J.J. (Physics Department (FM-15), University of Washington, Seattle, Washington (USA))

    1991-10-01T23:59:59.000Z

    We have measured the off-center displacements of the Nb ions in KTa{sub 0.91}Nb{sub 0.09}O{sub 3} as a function of temperature both below and above the ferroelectric transition temperature {ital T}{sub {ital c}}=85.6 K. The purpose of these measurements was to elucidate the basic nature of the ferroelectric phase transitions in mixed perovskites. The off-center displacements were determined by x-ray-absorption fine-structure (XAFS) measurements. The data were analyzed by calculating the XAFS spectra theoretically as a function of structural and other parameters and by refining these parameters to obtain the best fit with the experimental results up to the third coordination shell. In these calculations we used curved photoelectron wave functions and took into account multiple scattering up to and including, the third-order collinear scattering. It is found that these scattering contributions are both necessary and sufficient in order to account for all the scattering contributions with a total scattering path length of 8 A or less. At 70 K the off-center displacement, relative to the oxygen octahedra, is found to be 0.145 A in the (111) direction. These displacements change by less than 20% from 70 K to room temperature, namely, from below to far above the phase transition. These results lead to the conclusion that the magnitude of the displacements hardly changes over a very wide temperature range. Thus, the ferroelectric transition is not displacive and the main change taking place at the phase transition is from a disordered to orientationally ordered arrangement of displacements.

  4. Electron-doping through La{sup III}-for-Sr{sup II} substitution in (Sr{sub 1-} {sub x} La {sub x} ){sub 2}FeTaO{sub 6}: Effects on the valences and ordering of the B-site cations, Fe and Ta

    SciTech Connect (OSTI)

    Rautama, E.-L. [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Laboratory of Inorganic and Analytical Chemistry, Helsinki University of Technology, FIN-02015 HUT (Finland); Chan, T.S. [Department of Chemistry and Center for Nano Storage Research, National Taiwan University, Taipei, (China); Liu, R.S. [Department of Chemistry and Center for Nano Storage Research, National Taiwan University, Taipei, (China); Chen, J.M. [National Synchrotron Radiation Research Center, Hsinchu, (China); Yamauchi, H. [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Karppinen, M. [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan)]. E-mail: karppinen@msl.titech.ac.jp

    2006-01-15T23:59:59.000Z

    We have employed aliovalent A-site cation substitution, La{sup III}-for-Sr{sup II}, to dope the Sr(Fe{sub 0.5}Ta{sub 0.5})O{sub 3} perovskite oxide with electrons. Essentially single-phase samples of (Sr{sub 1-} {sub x} La {sub x} )(Fe{sub 0.5}Ta{sub 0.5})O{sub 3} were successfully synthesized up to x{approx}0.3 in a vacuum furnace at 1400 deg. C. The samples were found to crystallize (rather than with orthorhombic symmetry) in monoclinic space group P2{sub 1}/n that accounts for the partial ordering of the B-site cations, Fe and Ta. With increasing La-substitution level, x, the degree of Fe/Ta order was found to increase such that the La-richest compositions are best described by the B-site ordered double-perovskite formula (Sr,La){sub 2}FeTaO{sub 6}. From Fe L {sub 3} and Ta L {sub 3} XANES spectra it was revealed that upon electron doping the two B-site cations, Fe{sup III} and Ta{sup V}, are both prone to reduction. Magnetic susceptibility measurements showed spin-glass type behaviour for all the samples with a transition temperature slightly increasing with increasing x. -- Graphical abstract: Valence states of Fe and Ta are controlled in the partially ordered perovskite oxide (Sr,La){sub 2}FeTaO{sub 6}, through aliovalent La{sup III}-for-Sr{sup II} substitu0010ti.

  5. Development of Nb3Sn 11 T single aperture demonstrator dipole for LHC upgrades

    SciTech Connect (OSTI)

    Zlobin, A.V.; Apollinari, G.; Andreev, N.; Barzi, E.; Kashikhin, V.V.; Nobrega, f.; Novitski, I.; /Fermilab; Auchmann, B.; Karppinen, M.; Rossi, L.; /CERN

    2011-03-01T23:59:59.000Z

    The LHC collimation upgrade foresees additional collimators installed in dispersion suppressor regions. To obtain the necessary space for the collimators, a solution based on the substitution of LHC main dipoles for stronger dipoles is being considered. CERN and FNAL have started a joint program to demonstrate the feasibility of Nb{sub 3}Sn technology for this purpose. The goal of the first phase is the design and construction of a 2-m long single-aperture demonstrator magnet with a nominal field of 11 T at 11.85 kA with 20% margin. This paper describes the magnetic and mechanical design of the demonstrator magnet and summarizes its design parameters.

  6. A micro-compression study of shape-memory deformation in U-13at%Nb

    SciTech Connect (OSTI)

    Clarke, Amy J [Los Alamos National Laboratory; Field, Robert D [Los Alamos National Laboratory; Dickerson, Patricia O [Los Alamos National Laboratory; Mccabe, Rodney J [Los Alamos National Laboratory

    2008-01-01T23:59:59.000Z

    Micro-compression specimens, 1O-15{mu}m in diameter by 20-30{mu}m in height, were produced from individual parent grains in a polycrystalline U-13at%Nb shape-memory alloy using the focused ion beam (FIB) technique. The specimens were tested in a nanoindentation instrument with a flat diamond tip to investigate stress-strain behavior as a function of crystallographic orientation. The results are in qualitative agreement with a single-crystal accommodation strain (Bain strain) model of the shape-memory effect for this alloy.

  7. Fabrication and Test Results of a Nb3Sn Superconducting Racetrack Dipole Magnet

    SciTech Connect (OSTI)

    Chow, K.; Dietderich, D.R.; Gourlay, S.A.; Gupta, R.; Harnden, W.; Lietzke, A. F.; McInturff, A.D.; Millos, G.A.; Morrison, L.; Morrison, M.; Scanlan, R.M.

    2000-02-06T23:59:59.000Z

    A 'proof-of-principle' Nb{sub 3}Sn superconducting dual-bore dipole magnet was built from racetrack coils, as a first step in a program to develop an economical, 15 Tesla, accelerator-quality magnet. The mechanical design and magnet fabrication procedures are discussed. No training was required to achieve temperature-dependent plateau currents, despite several thermal cycles that involved partial magnet disassembly and substantial pre-load variations. Subsequent magnets are expected to approach 15 Tesla with substantially improved conductor.

  8. Optical ridge waveguides in AlGaAs and LiNbO3 

    E-Print Network [OSTI]

    Terry, Roger Mark

    1993-01-01T23:59:59.000Z

    the properties of ridge waveguides in AlGaAs, and also to develop and characterize low loss optical waveguides in LiNbOs that combine ridge geometry with the photoelastic efFect. A model that predicts strain contours and related ref'ractive index distribution... waveguides is important. This would establish profiles of the index distribution and guided modal fields, and permit adjustments of ridge height and film thickness for obtaining maximum coupling efilciencies. A computer model using the relaxation method...

  9. Design and Fabrication of a Single-Aperture 11T Nb3Sn Dipole Model for LHC Upgrades

    SciTech Connect (OSTI)

    Andreev, N.; Apollinari, G.; Barzi, E.; Bossert, R.; Nobrega, F.; Novitski, I.; Turrioni, D.; Yamada, R.; Zlobin, A.V.; /Fermilab; Auchmann, B.; Karppinen, M.; /CERN

    2011-11-28T23:59:59.000Z

    The planned upgrade of the LHC collimation system includes additional collimators to be installed in the dispersion suppressor areas of points 2, 3 and 7. To provide the necessary longitudinal space for the collimators, a replacement of 8.33 T Nb-Ti LHC main dipoles with 11 T dipoles based on Nb{sub 3}Sn superconductor compatible with the LHC lattice and main systems is being considered. To demonstrate this possibility FNAL and CERN have started a joint program to develop a 2 m long single-aperture dipole magnet with the nominal field of 11 T at {approx}11.85 kA current and 60 mm bore. This paper describes the demonstrator magnet magnetic and mechanical designs and analysis, coil fabrication procedure. The Nb{sub 3}Sn strand and cable parameters and test results are also reported.

  10. Leaky surface acoustic waves in Z-LiNbO{sub 3} substrates with epitaxial AIN overlays

    SciTech Connect (OSTI)

    Bu, G.; Ciplys, D.; Shur, M.S.; Namkoong, G.; Doolittle, W.A.; Hunt, W.D. [Department of Electrical, Computer, and Systems Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590 (United States); Georgia Institute of Technology, School of Electrical and Computer Engineering, Microelectronic Research Center, 791 Atlantic Drive, Atlanta, Georgia 30332-0269 (United States)

    2004-10-11T23:59:59.000Z

    The properties of leaky surface acoustic waves (LSAW) in MBE grown AIN layer on Z-cut LiNbO{sub 3} structures have been studied by numerical simulation and experimental measurements and compared with those of Rayleigh waves in the same structure. In the range of AIN layer thicknesses studied (0NbO{sub 3} substrate was essentially constant at around 4400 m/s. The measured electromechanical coupling coefficients (K{sup 2}) for the LSAW are roughly 1/4 of the predicted values, which might be due to the strong attenuation of the leaky wave unaccounted for during the parameter extraction. The thin AIN film slightly improved the measured temperature coefficient of frequency for the LSAW over that attained for the Z-cut, X-propagating LiNbO{sub 3} substrate alone.

  11. Simulation of Non-linear SRF losses derived from characteristic Nb topography: comparison of etched and electropolished surfaces

    E-Print Network [OSTI]

    Xu, Chen; Kelley, Michael J

    2014-01-01T23:59:59.000Z

    A simplified numerical model has been developed to simulate non-linear superconducting rf losses on Nb surfaces due exclusively to topographical enhancement of surface magnetic fields. If local sharp edges are small enough, at locations where local surface fields exceed Hc, small volumes of material may become normal conducting without thermal runaway leading to quench. These small volumes of normal material yield increases in the effective surface resistance of the Nb. Using topographic data from typical BCP'd and EP'd fine grain niobium, we have simulated field-dependent losses and find that when extrapolated to resulting cavity performance, these losses correspond well to characteristic BCP/EP high field Q0 performance differences for fine grain Nb. We describe the structure of the model, its limitations, and the effects of this type of non-linear loss contribution on SRF cavity performance.

  12. Quasiparticle interference, quasiparticle interactions, and the origin of the charge density wave in 2H-NbSe?

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Arguello, C. J.; Valla, T.; Rosenthal, E. P.; Andrade, E. F.; Jin, W.; Yeh, P. C.; Zaki, N.; Jia, S.; Cava, R. J.; Fernandes, R. M.; et al

    2015-01-01T23:59:59.000Z

    We show that a small number of intentionally introduced defects can be used as a spectroscopic tool to amplify quasiparticle interference in 2H-NbSe?, that we measure by scanning tunneling spectroscopic imaging. We show from the momentum and energy dependence of the quasiparticle interference that Fermi surface nesting is inconsequential to charge density wave formation in 2H-NbSe?. We demonstrate that by combining quasiparticle interference data with additional knowledge of the quasiparticle band structure from angle resolved photoemission measurements, one can extract the wavevector and energy dependence of the important electronic scattering processes thereby obtaining direct information both about the fermiology andmore »the interactions. In 2H-NbSe?, we use this combination to show that the important near-Fermi-surface electronic physics is dominated by the coupling of the quasiparticles to soft mode phonons at a wave vector different from the CDW ordering wave vector.« less

  13. Quasiparticle interference, quasiparticle interactions, and the origin of the charge density wave in 2H-NbSe?

    SciTech Connect (OSTI)

    Arguello, C. J. [Columbia Univ., New York, NY (United States); Valla, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Rosenthal, E. P. [Columbia Univ., New York, NY (United States); Andrade, E. F. [Columbia Univ., New York, NY (United States); Jin, W. [Columbia Univ., New York, NY (United States); Yeh, P. C. [Columbia Univ., New York, NY (United States); Zaki, N. [Columbia Univ., New York, NY (United States); Jia, S. [Princeton Univ., NJ (United States); Cava, R. J. [Princeton Univ., NJ (United States); Fernandes, R. M. [Univ., of Minnesota, Minneapolis, MN (United States); Millis, A. J. [Columbia Univ., New York, NY (United States); Osgood, Jr., R. M. [Columbia Univ., New York, NY (United States); Princeton Univ., Princeton, NJ (United States); Pasupathy, A. N. [Columbia Univ., New York, NY (United States)

    2015-01-01T23:59:59.000Z

    We show that a small number of intentionally introduced defects can be used as a spectroscopic tool to amplify quasiparticle interference in 2H-NbSe?, that we measure by scanning tunneling spectroscopic imaging. We show from the momentum and energy dependence of the quasiparticle interference that Fermi surface nesting is inconsequential to charge density wave formation in 2H-NbSe?. We demonstrate that by combining quasiparticle interference data with additional knowledge of the quasiparticle band structure from angle resolved photoemission measurements, one can extract the wavevector and energy dependence of the important electronic scattering processes thereby obtaining direct information both about the fermiology and the interactions. In 2H-NbSe?, we use this combination to show that the important near-Fermi-surface electronic physics is dominated by the coupling of the quasiparticles to soft mode phonons at a wave vector different from the CDW ordering wave vector.

  14. Quasiparticle interference, quasiparticle interactions, and the origin of the charge density wave in 2H-NbSe?

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Arguello, C. J. [Columbia Univ., New York, NY (United States); Valla, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Rosenthal, E. P. [Columbia Univ., New York, NY (United States); Andrade, E. F. [Columbia Univ., New York, NY (United States); Jin, W. [Columbia Univ., New York, NY (United States); Yeh, P. C. [Columbia Univ., New York, NY (United States); Zaki, N. [Columbia Univ., New York, NY (United States); Jia, S. [Princeton Univ., NJ (United States); Cava, R. J. [Princeton Univ., NJ (United States); Fernandes, R. M. [Univ., of Minnesota, Minneapolis, MN (United States); Millis, A. J. [Columbia Univ., New York, NY (United States); Osgood, Jr., R. M. [Columbia Univ., New York, NY (United States); Princeton Univ., Princeton, NJ (United States); Pasupathy, A. N. [Columbia Univ., New York, NY (United States)

    2015-01-01T23:59:59.000Z

    We show that a small number of intentionally introduced defects can be used as a spectroscopic tool to amplify quasiparticle interference in 2H-NbSe?, that we measure by scanning tunneling spectroscopic imaging. We show from the momentum and energy dependence of the quasiparticle interference that Fermi surface nesting is inconsequential to charge density wave formation in 2H-NbSe?. We demonstrate that by combining quasiparticle interference data with additional knowledge of the quasiparticle band structure from angle resolved photoemission measurements, one can extract the wavevector and energy dependence of the important electronic scattering processes thereby obtaining direct information both about the fermiology and the interactions. In 2H-NbSe?, we use this combination to show that the important near-Fermi-surface electronic physics is dominated by the coupling of the quasiparticles to soft mode phonons at a wave vector different from the CDW ordering wave vector.

  15. Third-order optical nonlinear absorption in Bi1.95La1.05TiNbO9 thin films Hengzhi Chen a

    E-Print Network [OSTI]

    Cao, Wenwu

    Third-order optical nonlinear absorption in Bi1.95La1.05TiNbO9 thin films Hengzhi Chen a , Bin Yang online 1 June 2010 Keywords: Nonlinear optical absorption Bi1.95La1.05TiNbO9 Optical properties Single absorption coefficient were obtained by optical transmittance measurements. The film exhibits a high

  16. MECHANISM OF THE PHASE CHANGE IN PbK2LiNb5O15: Dielectric, structural, and Raman scattering studies

    E-Print Network [OSTI]

    Boyer, Edmond

    and ferroelectric phases and a complex structural change between them. High and low temperature phases at high and low temperatures, in paraelectric-paraelastic phase and in ferroelectric- ferroelastic phase + 5 Nb2O5 2 PbK2LiNb5O15 + 3CO2 We started from a mixture in stoichiometric proportions and ground

  17. M5Si3(M=Ti, Nb, Mo) Based Transition-Metal Silicides for High Temperature Applications

    SciTech Connect (OSTI)

    Zhihong Tang

    2007-12-01T23:59:59.000Z

    Transition metal silicides are being considered for future engine turbine components at temperatures up to 1600 C. Although significant improvement in high temperature strength, room temperature fracture toughness has been realized in the past decade, further improvement in oxidation resistance is needed. Oxidation mechanism of Ti{sub 5}Si{sub 3}-based alloys was investigated. Oxidation behavior of Ti{sub 5}Si{sub 3}-based alloy strongly depends on the atmosphere. Presence of Nitrogen alters the oxidation behavior of Ti{sub 5}Si{sub 3} by nucleation and growth of nitride subscale. Ti{sub 5}Si{sub 3.2} and Ti{sub 5}Si{sub 3}C{sub 0.5} alloys exhibited an excellent oxidation resistance in nitrogen bearing atmosphere due to limited dissolution of nitrogen and increased Si/Ti activity ratio. MoSi{sub 2} coating developed by pack cementation to protect Mo-based Mo-Si-B composites was found to be effective up to 1500 C. Shifting coating composition to T1+T2+Mo{sub 3}Si region showed the possibility to extend the coating lifetime above 1500 C by more than ten times via formation of slow growing Mo{sub 3}Si or T2 interlayer without sacrificing the oxidation resistance of the coating. The phase equilibria in the Nb-rich portion of Nb-B system has been evaluated experimentally using metallographic analysis and differential thermal analyzer (DTA). It was shown that Nb{sub ss} (solid solution) and NbB are the only two primary phases in the 0-40 at.% B composition range, and the eutectic reaction L {leftrightarrow} Nb{sub SS} + NbB was determined to occur at 2104 {+-} 5 C by DTA.

  18. Nb{sub 2}O{sub 5} hollow nanospheres as anode material for enhanced performance in lithium ion batteries

    SciTech Connect (OSTI)

    Sasidharan, Manickam [Department of Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502 (Japan)] [Department of Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502 (Japan); Gunawardhana, Nanda [Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan)] [Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan); Yoshio, Masaki, E-mail: yoshio@cc.saga-u.ac.jp [Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan)] [Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan); Nakashima, Kenichi, E-mail: nakashik@cc.saga-u.ac.jp [Department of Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502 (Japan)] [Department of Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502 (Japan)

    2012-09-15T23:59:59.000Z

    Graphical abstract: Nb{sub 2}O{sub 5} hollow nanosphere constructed electrode delivers high capacity of 172 mAh g{sup ?1} after 250 cycles and maintains structural integrity and excellent cycling stability. Highlights: ? Nb{sub 2}O{sub 5} hollow nanospheres synthesis was synthesized by soft-template. ? Nb{sub 2}O{sub 5} hollow nanospheres were investigated as anode material in Li-ion battery. ? Nanostructured electrode delivers high capacity of 172 mAh g{sup ?1} after 250 cycles. ? The electrode maintains the structural integrity and excellent cycling stability. ? Nanosized shell domain facilitates fast lithium intercalation/deintercalation. -- Abstract: Nb{sub 2}O{sub 5} hollow nanospheres of average diameter ca. ?29 nm and hollow cavity size ca. 17 nm were synthesized using polymeric micelles with core–shell–corona architecture under mild conditions. The hollow particles were thoroughly characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermal (TG/DTA) and nitrogen adsorption analyses. Thus obtained Nb{sub 2}O{sub 5} hollow nanospheres were investigated as anode materials for lithium ion rechargeable batteries for the first time. The nanostructured electrode delivers high capacity of 172 mAh g{sup ?1} after 250 cycles of charge/discharge at a rate of 0.5 C. More importantly, the hollow particles based electrodes maintains the structural integrity and excellent cycling stability even after exposing to high current density 6.25 A g{sup ?1}. The enhanced electrochemical behavior is ascribed to hollow cavity coupled with nanosized Nb{sub 2}O{sub 5} shell domain that facilitates fast lithium intercalation/deintercalation kinetics.

  19. Effect of Ca Doping on the Electrical Conductivity of the High-Temperature Proton Conductor LaNbO4

    SciTech Connect (OSTI)

    Bi, Zhonghe [ORNL; Pena-Martinez, Juan [ORNL; Kim, Jung-Hyun [ORNL; Bridges, Craig A [ORNL; Huq, Ashfia [ORNL; Hodges, Jason P [ORNL; Paranthaman, Mariappan Parans [ORNL

    2012-01-01T23:59:59.000Z

    The sintering properties, crystal structure and electrical conductivity of La1-xCaxNbO4- (x=0, 0.005, 0.01, 0.015, 0.02 and 0.025), prepared by a conventional solid-state method, have been investigated using powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). In 2.5% Ca doped samples, a small amount of impurities Ca2Nb2O7 were observed from the XRD patterns. Impedance spectra show that the grain boundary resistance increases with increasing Ca content, while the bulk resistance remains essentially constant below 550 C. Despite the higher degree of grain growth was observed for higher Ca-doping levels, the total conductivity of the La1-xCaxNbO4- series decreases with increasing Ca content from 0.5 to 2.0 mol%. The activation energy for the total conductivity decreases with increasing Ca content from 0.71 eV (x=0) to 0.54 eV (x=0.01) for the high temperature tetragonal phase, then it increases to 0.60 eV for x=0.02. For the monoclinic phase, La0.995Ca0.005NbO4- shows the lowest activation energy of 1.26 eV. These results imply that the solubility of CaO in LaNbO4 is in the range from 0.5 to 1.0 mol%. By increasing the sintering temperature from 1500 C to 1550 C, the proton conductivity of the Ca-doped LaNbO4 was improved with enlarged grain size due to a reduction in the resistive grain boundary contribution.

  20. {delta}{sup 0} resonance production in peripheral 4.2A GeV C+Ta collisions

    SciTech Connect (OSTI)

    Simic, Lj.; Milosavljevic, M. Vranjes; Mendas, I.; Popovic, D. S. [Institute of Physics, University of Belgrade, P. O. Box 68, 11081 Belgrade (Serbia); Krpic, D. [Faculty of Physics, University of Belgrade, P. O. Box 368, 11001 Belgrade (Serbia)

    2009-07-15T23:59:59.000Z

    The production of {delta}{sup 0}(1232){yields}p{pi}{sup -} resonance is studied in peripheral C+Ta collisions at 4.2A GeV using the 2-m propane bubble chamber exposed at JINR Dubna Synchrophasotron. Using an invariant mass distribution of p{pi}{sup -} pairs and additional kinematical constrains, the mass, width, and kinematical characteristics of {delta}{sup 0} resonance are determined. The ratio of the number of pions originated from {delta}{sup 0} resonance decay to the number of all pions (resonant and nonresonant) is estimated. The analogous ratio for protons is also determined.

  1. A reinvestigation of the electrochemical behavior of Nb(V) in AlCl[sub 3]-NaCl[sub SAT] and related melts

    SciTech Connect (OSTI)

    Sienerth, K.D. (Virginia Military Inst., Lexington, VA (United States). Dept. of Chemistry); Hondrogiannis, E.M.; Mamantov, G. (Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry)

    1994-07-01T23:59:59.000Z

    The electrochemistry and spectroelectrochemistry of Nb(V) in molten sodium chloroaluminate saturated with NaCl at 178 C were re-examined. It was determined that previous studies involved solutions of high oxide content. The reduction of NbCl[sub 5] in oxide-free melts was found to proceed via four steps at short times and low concentrations. At higher concentrations and long times, the reduction sequence was complicated by a chemical reaction which followed the initial reduction step. The effect of temperature on the electrochemistry of Nb(V) in sodium chloroaluminate and fluorochloraluminates was examined; temperature had a marked effect on the behavior of Nb(V) in these melts, but no significant differences were observed between melts with and those without fluoride. Attempts to produce electrolytically niobium metal from Nb(V) in these metals met with limited success.

  2. Preliminary study of niobium alloy contamination by transport through helium. [Nb-1Zr; Sm-Co; Hiperco 50 steel; alumina

    SciTech Connect (OSTI)

    Scheuermann, C.M.; Moore, T.J.; Wheeler, D.R.

    1987-01-12T23:59:59.000Z

    Preliminary tests were conducted to determine if interstitial element transport through a circulating helium working fluid was a potential problem in Brayton and Stirling space power systems. Test specimens exposed to a thermal gradient for up to 3000 h included Nb-1%Zr, a Sm-Co alloy, Hiperco 50 steel, and alumina to simulate various engine components of the Brayton and Stirling systems. Results indicate that helium transport of interstitial contaminants can be minimized over a 7-y life with monometallic Nb-1%Zr design. Exposure with other materials indicated a potential for interstitial contaminant transport.

  3. New high pressure rare earth tantalates RE{sub x}Ta{sub 2}O{sub 5+1.5x} (RE=La, Eu, Yb)

    SciTech Connect (OSTI)

    Zibrov, Igor P., E-mail: zibrov@mail.ru [Institute for High Pressure Physics, Russian Academy of Sciences, Kaluzhskoe Highway 14, Troitsk, Moscow 142190 (Russian Federation); Filonenko, Vladimir P., E-mail: filv@hppi.troitsk.ru [Institute for High Pressure Physics, Russian Academy of Sciences, Kaluzhskoe Highway 14, Troitsk, Moscow 142190 (Russian Federation); Zakharov, Nikolai D., E-mail: zakharov@mpi-halle.mpg.de [Max Planck Institute for Microstructure Physics, Weinberg 2, D-06120 Halle/Saale (Germany); Werner, Peter, E-mail: werner@mpi-halle.mpg.de [Max Planck Institute for Microstructure Physics, Weinberg 2, D-06120 Halle/Saale (Germany); Drobot, Dmitrii V., E-mail: dvdrobot@mail.ru [Lomonosov Moscow University of Fine Chemical Technology, Prospect Vernadskogo 86, Moscow 119571 (Russian Federation); Nikishina, Elena E.; Lebedeva, Elena N., E-mail: helena_nick@mail.ru [Lomonosov Moscow University of Fine Chemical Technology, Prospect Vernadskogo 86, Moscow 119571 (Russian Federation)

    2013-07-15T23:59:59.000Z

    Rare earth tantalates La{sub 0.075}Ta{sub 2}O{sub 5.113}, Eu{sub 0.089}Ta{sub 2}O{sub 5.134} and Yb{sub 0.051}Ta{sub 2}O{sub 5.077} have been prepared by solid state reaction at P=7.0 GPa and T=1050–1100 °C and studied by X-ray diffraction, thermal analysis and electron microscopy. Low hydrated amorphous tantalum, lanthanum, europium and ytterbium hydroxides were used as starting materials. Aqueous as well as anhydrous compounds were obtained. Title tantalates are crystallized in the structure type of F–Ta{sub 2}O{sub 5} [Zibrov et al. Russ. J. Inorg. Chem. 48 (2003) 464–471] [5]. The structure was refined by the Rietveld method from X-ray powder diffractometer data: La{sub 0.075}Ta{sub 2}O{sub 5.113}, a=10.5099(2), b=7.2679(1), c=6.9765(1) Ĺ, V=532.90(1) Ĺ{sup 3}, Z=6, space group Ibam; Eu{sub 0.089}Ta{sub 2}O{sub 5.134}, a=10.4182(3), b=7.2685(1), c=6.9832(1) Ĺ, V=528.80(2) Ĺ{sup 3}, Z=6, space group Ibam; Yb{sub 0.051}Ta{sub 2}O{sub 5.077}, a=10.4557(2), b=7.3853(1), c=6.8923(1) Ĺ, V=532.21(1) Ĺ{sup 3}, Z=6, space group Ibam. RE atoms do not replace the tantalum in its positions but the only water in the channels of the structure. Highly charged cations RE{sup +3} compress the unit cell so that its volume becomes less than that of F–Ta{sub 2}O{sub 5}. Significant decrease of the unit cell volume after water removal from the structure is possible due to the puckering of pentagonal bipyramid layers and change of the corrugation angle in the layer. - Graphical abstract: The structure of RE{sub x}Ta{sub 2}O{sub 5+1.5x} and its HRTEM image (“A” arrows show empty channel, “B” arrows show filled channel). - Highlights: • We synthesized new tantalates of RE under high pressure high temperature conditions. • RE atoms replace water molecules in the channels of the structure. • Aqueous as well as anhydrous tantalates were obtained. • Highly charged cations RE{sup +3} compress the unit cell decreasing RE–O distances.

  4. Optical phonons and the soft mode in 2H-NbSe2

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Weber, F.; Hott, R.; Heid, R.; Bohnen, K.-P.; Rosenkranz, S.; Castellan, J.-P.; Osborn, R.; Said, A. H.; Leu, B. M.; Reznik, D.

    2013-06-01T23:59:59.000Z

    We present an investigation of the lattice dynamics of the charge density wave (CDW) compound 2H-NbSe2. We analyze the precise nature of the wave vector-dependent electron-phonon coupling (EPC) and derive the bare dispersion of the CDW soft phonon mode using inelastic x-ray scattering combined with ab initio calculations. Experimentally, phonon modes along the ??M line, i.e., q = (h,0,0), with 0 ? h ? 0.5 and the same longitudinal symmetry (?1) as the CDW soft mode, were investigated up to 32 meV. In agreement with our calculations, we observe significant EPC in the optic modes at h ? 0.2. We analyze the EPC in the optic, as well as acoustic, mode and show that the q dependences stem from scattering processes between two bands at the Fermi surface that both have a Nb 4d character. Finally, we demonstrate that the soft mode dispersion at T = 33 K (=TCDW) can be well described on the basis of a strongly q-dependent EPC matrix element and an acousticlike bare phonon dispersion in agreement with observations near room temperature.

  5. Progress in the long Nb3Sn quadrupole R&D by LARP

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ambrosio, G; Andreev, N; Anerella, M; Barzi, E; Bocian, D; Bossert, R; Buehler, M; Caspi, S; Chlachidze, G; Dietderich, D; et al

    2012-06-01T23:59:59.000Z

    After the successful test of the first long Nb3Sn quadrupole (LQS01) the US LHC Accelerator Research Program (LARP, a collaboration of BNL, FNAL, LBNL and SLAC) is assessing training memory, reproducibility, and other accelerator quality features of long Nb3Sn quadrupole magnets. LQS01b (a reassembly of LQS01 with more uniform and higher pre-stress) was subjected to a full thermal cycle and reached the previous plateau of 222 T/m at 4.5 K in two quenches. A new set of four coils, made of the same type of conductor used in LQS01 (RRP 54/61 by Oxford Superconducting Technology), was assembled in the LQS01more »structure and tested at 4.5 K and lower temperatures. The new magnet (LQS02) reached the target gradient (200 T/m) only at 2.6 K and lower temperatures, at intermediate ramp rates. The preliminary test analysis, here reported, showed a higher instability in the limiting coil than in the other coils of LQS01 and LQS02.« less

  6. Experimental investigation of copper matrix longitudinal resistance in a composite Nb-Ti wire

    SciTech Connect (OSTI)

    Gubkin, I.N.; Kozlenkova, N.I.; Nikulin, A.D.; Polikarpova, M.V.; Filkin, V.Ya. (A.A. Bochvar Inst. of Inorganic Materials, Moscow (Russian Federation))

    1994-07-01T23:59:59.000Z

    The longitudinal resistance of multifilamentary superconducting wires is among the major parameters used in design and optimization of superconducting magnetic systems. To enhance the conductivity of the copper matrix, it is made of pipes and rods of enhanced quality copper produced by electron beam melting (resistance ratio between two temperatures, 295 K and 4.2 K, R[sub 295]/R[sub 4.2] > 200). Yet for readily obtainable conductors this parameter is much lower. The reduction of the copper-matrix electrical conductivity may be attributed to wire-production technology involving processes such as extrusion, drawing and intermediate thermal processing, as well as to the size effect. Copper-matrix longitudinal resistance was studied as a function of wire diameter on specimens of multifilamentary Nb-Ti wire with filaments coated by a Nb layer. Experimental results are compared with the Sondheimer calculations for a monofilament conductor as well as with the Gavalloni calculations for an ideal wire with hexagonally located filaments. It has been shown that the best fit with the experiment is provided by the Sondheimer approximation. Comparison of the results of this work with other authors' data obtained for the specimens with no niobium barrier, allows the authors to single out the influence of a pure size effect and diffusion of Ti on the resistivity.

  7. Magnetic properties of Fe-Cu-Nb-Si-B nanocrystalline magnetic alloys

    SciTech Connect (OSTI)

    Garcia del Muro, M.; Batlle, X.; Zquiak, R.; Tejada, J. [Univ. de Barcelona (Spain). Dept. de Fisica Fonamental] [Univ. de Barcelona (Spain). Dept. de Fisica Fonamental; Polak, C.; Groessinger, R. [Technische Univ., Vienna (Austria). Inst. fuer Experimental Physik] [Technische Univ., Vienna (Austria). Inst. fuer Experimental Physik

    1994-03-01T23:59:59.000Z

    Several ribbons of composition Fe{sub 73.5}Cu{sub 1}Nb{sub 3}Si{sub 16.5}B{sub 6} and Fe{sub 73.5}Cu{sub 1}Nb{sub 3}Si{sub 13.5}B{sub 9} were prepared by annealing the as-quenched samples between 525 C and 700 C, which induced nucleation of nanocrystallites of Fe bcc-type composition. Mean grain sizes were obtained from X-ray diffraction. Static magnetic properties were measured with both a Magnet Physik Hysteresis-Graph (up to 200 Oe) and a SHE S.Q.U.I.D. Magnetometer (up to 50 kOe). Soft magnetic parameters (coercive field and initial permeability) were very sensitive to grain size. The ZFC magnetization at low field showed a broad peak at a temperature T{sub M}, thus signaling a certain distribution of nanocrystalline sizes, and T{sub M} strongly decreased when the mean grain size decreased. Isothermal magnetization curves at low temperature showed the expected asymptotic behavior of a random magnet material at low and high fields.

  8. FEMCAM Analysis of SULTAN Test Results for ITER Nb3SN Cable-conduit Conductors

    SciTech Connect (OSTI)

    Yuhu Zhai, Pierluigi Bruzzone, Ciro Calzolaio

    2013-03-19T23:59:59.000Z

    Performance degradation due to filament fracture of Nb3 Sn cable-in-conduit conductors (CICCs) is a critical issue in large-scale magnet designs such as ITER which is currently being constructed in the South of France. The critical current observed in most SULTAN TF CICC samples is significantly lower than expected and the voltage-current characteristic is seen to have a much broader transition from a single strand to the CICC. Moreover, most conductors exhibit the irreversible degradation due to filament fracture and strain relaxation under electromagnetic cyclic loading. With recent success in monitoring thermal strain distribution and its evolution under the electromagnetic cyclic loading from in situ measurement of critical temperature, we apply FEMCAM which includes strand filament breakage and local current sharing effects to SULTAN tested CICCs to study Nb3 Sn strain sensitivity and irreversible performance degradation. FEMCAM combines the thermal bending effect during cool down and the EM bending effect due to locally accumulating Lorentz force during magnet operation. It also includes strand filament fracture and related local current sharing for the calculation of cable n value. In this paper, we model continuous performance degradation under EM cyclic loading based on strain relaxation and the transition broadening upon cyclic loading to the extreme cases seen in SULTAN test data to better quantify conductor performance degradation.

  9. Design of HD2: a 15 T Nb3Sn dipole with a 35 mm bore

    SciTech Connect (OSTI)

    Sabbi, G.; Bartlett, S. E.; Caspi, S.; Dietderich, D. R.; Ferracin, P.; Gourlay, S. A.; Hannaford, C. R.; Hafalia, A. R.; Lietzke, A. F.; Mattafirri, S.; McInturff, A. D.; Scanlan, R.

    2005-06-01T23:59:59.000Z

    The Nb{sub 3}Sn dipole HD1, recently fabricated and tested at LBNL, pushes the limits of accelerator magnet technology into the 16 T field range, and opens the way to a new generation of HEP colliders. HD1 is based on a flat racetrack coil configuration and has a 10 mm bore. These features are consistent with the HD1 goals: exploring the Nb{sub 3}Sn conductor performance limits at the maximum fields and under high stress. However, in order to further develop the block-coil geometry for future high-field accelerators, the bore size has to be increased to 30-50 mm. With respect to HD1, the main R&D challenges are: (a) design of the coil ends, to allow a magnetically efficient cross-section without obstructing the beam path; (b) design of the bore, to support the coil against the pre-load force; (c) correction of the geometric field errors. HD2 represents a first step in addressing these issues, with a central dipole field above 15 T, a 35 mm bore, and nominal field harmonics within a fraction of one unit. This paper describes the HD2 magnet design concept and its main features, as well as further steps required to develop a cost-effective block-coil design for future high-field, accelerator-quality dipoles.

  10. LARP NB3SN QUADRUPOLE MAGNETS FOR THE LHC LUMINOSITY UPGRADE

    SciTech Connect (OSTI)

    Ferracin, P.

    2009-06-01T23:59:59.000Z

    The US LHC Accelerator Research Program (LARP) is a collaboration between four US laboratories (BNL, FNAL, LBNL, and SLAC) aimed at contributing to the commissioning and operation of the LHC and conducting R&D on its luminosity upgrade. Within LARP, the Magnet Program's main goal is to demonstrate that Nb{sub 3}Sn superconducting magnets are a viable option for a future upgrade of the LHC Interaction Regions. Over the past four years, LARP has successfully fabricated and tested several R&D magnets: (1) the subscale quadrupole magnet SQ, to perform technology studies with 300 mm long racetrack coils, (2) the technology quadrupole TQ, to investigate support structure behavior with 1 m long cos2{theta} coils, and (3) the long racetrack magnet LR, to test 3.6 m long racetrack coils. The next milestone consists in the fabrication and test of the 3.7 m long quadrupole magnet LQ, with the goal of demonstrating that ND{sub 3}Sn technology is mature for use in high energy accelerators. After an overview of design features and test results of the LARP magnets fabricated so far, this paper focuses on the status of the fabrication of LQ: we describe the production of the 3.4 m long cos2{theta} coils, and the qualification of the support structure. Finally, the status of the development of the next 1 m long model HQ, conceived to explore stress and field limits of Nb{sub 3}Sn superconducting magnets, is presented.

  11. Design and Test of a Nb3Sn Subscale Dipole Magnet for Training Studies

    SciTech Connect (OSTI)

    Felice, Helene; Caspi, Shlomo; Dietderich, Daniel R.; Felice, Helene; Ferracin, Paolo; Gourlay, Steve A.; Hafalia, Aurelo R.; Lietzke, Alan F.; Mailfert, Alain; Sabbi, GainLuca; Vedrine, Pierre

    2007-06-01T23:59:59.000Z

    As part of a collaboration between CEA/Saclay and the Superconducting Magnet Group at LBNL, a subscale dipole structure has been developed to study training in Nb3Sn coils under variable pre-stress conditions. This design is derived from the LBNL Subscale Magnet and relies on the use of identical Nb{sub 3}Sn racetrack coils. Whereas the original LBNL subscale magnet was in a dual bore 'common-coil' configuration, the new subscale dipole magnet (SD) is assembled as a single bore dipole made of two superposed racetrack coils. The dipole is supported by a new mechanical structure developed to withstand the horizontal and axial Lorentz forces and capable of applying variable vertical, horizontal and axial preload. The magnet was tested at LBNL as part of a series of training studies aiming at understanding of the relation between pre-stress and magnet performance. Particular attention is given to the coil ends where the magnetic field peaks and stress conditions are the least understood. After a description of SD design, assembly, cool-down and tests results are reported and compared with the computations of the OPERA3D and ANSYS magnetic and mechanical models.

  12. Progress in the long Nb3Sn quadrupole R&D by LARP

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ambrosio, G [Fermilab; Andreev, N [Brookhaven; Anerella, M [Fermilab; Barzi, E [LBL, Berkeley; Bocian, D [Fermilab; Bossert, R [LBL, Berkeley; Buehler, M [Fermilab; Caspi, S [Brookhaven; Chlachidze, G [Berkeley; Dietderich, D [Brookhaven; DiMarco, J [Fermilab

    2012-06-01T23:59:59.000Z

    After the successful test of the first long Nb3Sn quadrupole (LQS01) the US LHC Accelerator Research Program (LARP, a collaboration of BNL, FNAL, LBNL and SLAC) is assessing training memory, reproducibility, and other accelerator quality features of long Nb3Sn quadrupole magnets. LQS01b (a reassembly of LQS01 with more uniform and higher pre-stress) was subjected to a full thermal cycle and reached the previous plateau of 222 T/m at 4.5 K in two quenches. A new set of four coils, made of the same type of conductor used in LQS01 (RRP 54/61 by Oxford Superconducting Technology), was assembled in the LQS01 structure and tested at 4.5 K and lower temperatures. The new magnet (LQS02) reached the target gradient (200 T/m) only at 2.6 K and lower temperatures, at intermediate ramp rates. The preliminary test analysis, here reported, showed a higher instability in the limiting coil than in the other coils of LQS01 and LQS02.

  13. http://www-db.in.tum.de/research/projects/StreamGlobe Optimization Techniques

    E-Print Network [OSTI]

    Kemper, Alfons

    : Redundant transmission of data streams Redundant execution of stream transforming operators Transmissionhttp://www-db.in.tum.de/research/projects/StreamGlobe Optimization Techniques: In-network query processing o Distribute query processing operators in the network (query shipping) o Early filtering

  14. Managing the History of Metadata in support for DB Archiving and Schema Evolution

    E-Print Network [OSTI]

    Zaniolo, Carlo

    Managing the History of Metadata in support for DB Archiving and Schema Evolution Carlo A. Curino1 the necessity to manage them and preserve the schema evolution history. In this paper, we describe the Panta Rhei Framework designed to provide powerful tools that: (i) facilitate schema evolution and guide

  15. MicrobeDB: a locally maintainable database of microbial genomic Morgan G. I. Langille1,*

    E-Print Network [OSTI]

    Hammerton, James

    MicrobeDB: a locally maintainable database of microbial genomic sequences Morgan G. I. Langille1 Genome Center, University of California Davis, Davis, California, USA ABSTRACT Summary: Analysis of microbial genomes often requires the general organization and comparison of tens to thousands of genomes

  16. Floodplain Assessment for the Proposed Engineered Erosion Controls at TA-72 in Lower Sandia Canyon, Los Alamos National Laboratory

    SciTech Connect (OSTI)

    Hathcock, Charles D. [Los Alamos National Laboratory

    2012-08-27T23:59:59.000Z

    Los Alamos National Laboratory (LANL) is preparing to implement engineering controls in Sandia Canyon at Technical Area (TA) 72. Los Alamos National Security (LANS) biologists conducted a floodplain determination and this project is located within a 100-year floodplain. The proposed project is to rehabilitate the degraded channel in lower Sandia Canyon where it crosses through the outdoor firing range at TA-72 to limit the loss of sediment and dissipate floodwater leaving LANL property (Figure 1). The proposed construction of these engineered controls is part of the New Mexico Environment Department's (NMED) approved LANL Individual Storm Water Permit. The purpose of this project is to install storm water controls at Sandia Watershed Site Monitoring Area 6 (S-SMA-6). Storm water controls will be designed and installed to meet the requirements of NPDES Permit No. NM0030759, commonly referred to as the LANL Individual Storm Water Permit (IP). The storm water control measures address storm water mitigation for the area within the boundary of Area of Concern (AOC) 72-001. This action meets the requirements of the IP for S-SMA-6 for storm water controls by a combination of: preventing exposure of upstream storm water and storm water generated within the channel to the AOC and totally retaining storm water falling outside the channel but within the AOC.

  17. Thermal stability of TaSi/sub x/-GaAs Schottky barriers in rapid thermal processing. [Self-aligned gate fabrication of GaAs MESFETs

    SciTech Connect (OSTI)

    Haynes, T.E.; Han, C.C.; Lau, S.S.; Picraux, S.T.; Chu, W.K.

    1987-01-01T23:59:59.000Z

    Co-sputtered TaSi/sub x/ films on GaAs have been examined as potential refractory Schottky barrier contacts suitable for self-aligned gate fabrication of GaAs MESFETs. Thermal stability of electrical and physical characteristics has been studied following furnace annealing and rapid thermal processing of contacts with compositions near Ta/sub 5/Si/sub 3/ (x = 0.6). Assessment of integrity of the annealed contacts has been made based on measurement of electrical characteristics, interface interdiffusion, and evaporation of GaAs through the contact. Superior stability as a function of anneal temperature up to 900/sup 0/C was achieved for TaSi/sub 0.6/ contacts using rapid thermal processing (RTP) techniques rather than furnace annealing. Current-voltage characteristics were found to be insensitive to RTP temperature between 700 and 900/sup 0/C.

  18. We report on the performance of a Nb voltage-biased superconducting bolometer cooled by a closed cycle pulse tube

    E-Print Network [OSTI]

    Naylor, David A.

    . INTRODUCTION AND BACKGROUND Historically, the sensitive detection of light at far-infrared wavelengths has been together with a large area Nb TES sensor. This results in a device that does not easily saturate under high of the inherent high dynamic range enabling a broad range of applications. II. RESULTS Experimental evaluation

  19. Invited Paper Progress in quasi-phasematched optical parametric oscifiators using periodically poled LiNbO3

    E-Print Network [OSTI]

    Byer, Robert L.

    power handling properties of single domain LiNbO3, and QPM allows noncritical phasematching, lithium niobate, infrared sources, tunable mid-JR generation, nonlinear optical materials, frequency the increase in interaction length. The availability of long crystals of this high-gain, low-loss material has

  20. Atomic structures and electronic properties of 2H-NbSe{sub 2}: The impact of Ti doping

    SciTech Connect (OSTI)

    Li, Hongping, E-mail: hpli@mail.ujs.edu.cn, E-mail: zcwang@wpi-aimr.tohoku.ac.jp; Chen, Lin; Zhang, Kun; Liang, Jiaqing; Tang, Hua; Li, Changsheng [Institute for Advanced Materials, School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Liu, Xiaojuan; Meng, Jian [State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Wang, Zhongchang, E-mail: hpli@mail.ujs.edu.cn, E-mail: zcwang@wpi-aimr.tohoku.ac.jp [Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

    2014-09-14T23:59:59.000Z

    Layered transition metal dichalcogenides have aroused renewed interest as electronic materials, yet their electronic performances could be modified by chemical doping. Here, we perform a systematic first-principles calculation to investigate the effect of Ti doping on atomic structure and electronic properties of the 2H-NbSe{sub 2}. We consider a total of three possible Ti-doping models and find that both the substitution and intercalated models are chemically preferred with the intercalation model being more favorable than the substitution one. Structural analyses reveal a slight lattice distortion triggered by Ti doping, but the original structure of 2H-NbSe{sub 2} is maintained. We also observe an expansion of c axis in the substituted model, which is attributed to the reduced van der Waals interaction arising from the increased Se-Se bond length. Our calculations also predict that the electron transport properties can be enhanced by the Ti doping, especially for the Ti-intercalated 2H-NbSe{sub 2}, which should be beneficial for the realization of superconductivity. Furthermore, the covalence element is found in the Ti-Se bonds, which is ascribed to the hybridization of Ti 3d and Se 4p orbitals. The findings indicate that doping of transition metals can be regarded as a useful way to tailor electronic states so as to improve electron transport properties of 2H-NbSe{sub 2}.

  1. Data:Eb22994e-248b-4752-8594-8233db7d9a12 | Open Energy Information

    Open Energy Info (EERE)

    3db7d9a12 No revision has been approved for this page. It is currently under review by our subject matter experts. Jump to: navigation, search Loading... 1. Basic Information 2....

  2. MvirDB: Microbial Database of Protein Toxins, Virulence Factors and Antibiotic Resistance Genes for Bio-Defense Applications

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

    Zhou, C. E.; Smith, J.; Lam, M.; Zemla, M. D.; Slezak, T.

    MvirDB is a cenntralized resource (data warehouse) comprising all publicly accessible, organized sequence data for protein toxins, virulence factors, and antibiotic resistance genes. Protein entries in MvirDB are annotated using a high-throughput, fully automated computational annotation system; annotations are updated periodically to ensure that results are derived using current public database and open-source tool releases. Tools provided for using MvirDB include a web-based browser tool and BLAST interfaces. MvirDB serves researchers in the bio-defense and medical fields. (taken from page 3 of PI's paper of same title published in Nucleic Acids Research, 2007, Vol.35, Database Issue (Open Source)

  3. Dispersion states and acid properties of SiO{sub 2}-supported Nb{sub 2}O{sub 5}

    SciTech Connect (OSTI)

    He, Jie, E-mail: jhe@aust.edu.cn [School of Chemical Engineering, Anhui University of Science and Technology, Huainan 232001 (China); Li, Qing-Jie [School of Chemical Engineering, Anhui University of Science and Technology, Huainan 232001 (China); Fan, Yi-Ning [Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)

    2013-06-15T23:59:59.000Z

    Nb{sub 2}O{sub 5}/SiO{sub 2} samples were prepared by the incipient-wetness impregnation method using niobium oxalate aqueous solution. The microstructure and dispersion process of the niobia species supported on SiO{sub 2} were characterized by means of power X-ray diffraction (XRD), laser Raman spectroscopy (LRS), and UV–vis diffuse reflectance spectroscopy (UV–vis DRS). The acid properties were investigated by the method of Hammett indicator and Pyridine adsorption infrared (Py-IR) spectroscopy. The results showed that the dispersion process of Nb{sub 2}O{sub 5} was performed by consuming surface hydroxyl groups of the amorphous SiO{sub 2} support. The aggregation of niobia species led to the formation of microcrystalline particles, so that there was no a clear monolayer dispersion capacity for Nb{sub 2}O{sub 5} supported on amorphous SiO{sub 2}. Furthermore, the catalytic activities of the as-prepared samples were evaluated by the condensation reaction of iso-butene (IB) and iso-butyraldehyde (IBA) to form 2,5-dimethyl-2,4-hexadiene (DMHD). The catalytic activities of the as-prepared samples for the condensation and their acid properties were strongly affected by the dispersion states. - Graphical abstract: The acid amount and strength of Nb{sub 2}O{sub 5}/SiO{sub 2} samples varied with the increase of Nb{sub 2}O{sub 5} loading. The catalytic activities of the as-prepared samples for the condensation and their acid properties were strongly affected by the dispersion states. - Highlights: • The dispersed process of Nb{sub 2}O{sub 5} was completed by consuming surface hydroxyl groups of SiO{sub 2}. • XRD quantitative phase analysis is not applicable for oxides dispersing on amorphous support. • The catalytic activity of Nb{sub 2}O{sub 5}/SiO{sub 2} is closely related to the dispersion state of SiO{sub 2}.

  4. Quadruple-layered perovskite (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13}

    SciTech Connect (OSTI)

    Kitada, A.; Tsujimoto, Y.; Yamamoto, T. [Department of Energy and Hydrocarbon Chemistry, Faculty of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Kobayashi, Y. [Department of Energy and Hydrocarbon Chemistry, Faculty of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); Narumi, Y. [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 (Japan); Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai 980-8577 (Japan); Kindo, K. [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 (Japan); Aczel, A.A.; Luke, G.M. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada); Uemura, Y.J. [Department of Physics, Columbia University, New York, NY 10027 (United States); Kiuchi, Y.; Ueda, Y. [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 (Japan); Yoshimura, K. [Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Ajiro, Y. [Department of Energy and Hydrocarbon Chemistry, Faculty of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); Kageyama, H., E-mail: kage@scl.kyoto-u.ac.jp [Department of Energy and Hydrocarbon Chemistry, Faculty of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Institute for Integrated Cell-Material Sciences, Kyoto University, Sakyo, Kyoto 606-8501 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi 332-0012 (Japan)

    2012-01-15T23:59:59.000Z

    We will present the synthesis, structure and magnetic properties of a new quadruple-layered perovskite (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13}. Through a topotactic ion-exchange reaction with CuCl{sub 2}, the precursor RbCa{sub 2}NaNb{sub 4}O{sub 13} presumably having an incoherent octahederal tliting changes into (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13} with a 2a{sub p} Multiplication-Sign 2a{sub p} Multiplication-Sign 2c{sub p} superstructure (tetragonal; a=7.73232(5) A, c=39.2156(4) A). The well-defined superstructure for the ion-exchanged product should be stabilized by the inserted CuCl{sub 4}O{sub 2} octahedral layers that firmly connect with neighboring perovskite layers. Magnetic studies show the absence of long-range magnetic ordering down to 2 K despite strong in-plane interactions. Aleksandrov Prime s group theory and Rietveld refinement of synchrotron X-ray diffraction data suggest the structure to be of I4/mmm space group with in-phase tilting along the a and b axes, a two-tilt system (++0). - Graphical Abstract: We present a quadruple-layered copper oxyhalide (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13} synthesized through a topotactic ion-exchange reaction of RbCa{sub 2}NaNb{sub 4}O{sub 13} with CuCl{sub 2}. The compound has a well-defined superstructure. Magnetic studies suggest the absence of magnetic order even at 2 K. Highlights: Black-Right-Pointing-Pointer (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13} was prepared by ion-exchange reaction of RbCa{sub 2}NaNb{sub 4}O{sub 13} with CuCl{sub 2}. Black-Right-Pointing-Pointer Compound has a 2a{sub p} Multiplication-Sign 2a{sub p} Multiplication-Sign 2c{sub p} superstructure (tetragonal; a=7.73 A, c=39.21 A). Black-Right-Pointing-Pointer Such a well-defined superstructure was not observed in the precursor compound. Black-Right-Pointing-Pointer Aleksandrov Prime s theory and Rietveld study suggest a (++0) octahedral tilting (I4/mmm). Black-Right-Pointing-Pointer Magnetic studies revealed the absence of magnetic order down to 2 K.

  5. Behavior of the electroless composite films plated from a Ni-P bath with metallic dispersion of Zr and Nb powders

    SciTech Connect (OSTI)

    Osaka, T.; Koiwa, I.; Usuda, M.; Arai, K.; Saito, I.

    1989-04-01T23:59:59.000Z

    An electroless Ni-Zr-P composite film and a Ni-Nb-P composite film were plated and their heat-treating behaviors were investigated. The addition of 20g dm/sup -3/ of metallic powder resulted in a composite film that contained 21.2 weight percent (w/o) of Zr. (13.8 atom percent (a/o)), or 4.8 w/o of Nb. (2.9 a/o), respectively. Both metallic powders were dispersed uniformly throughout the film. The metallic Ni formed by the crystallization on the Ni-P matrix diffused into the metallic powders, and the amorphous Ni-Zr and Ni-Nb phases were formed by heat-treatment at 500/sup 0/ or 300/sup 0/C. Some parts of the amorphous Ni-Zr phases and the metallic Ni phases combined to form intermetallic compounds by heat-treatment at 600/sup 0/C. The nickel-rich parts of the amorphous Ni-Nb phase were converted into a metastable Ni-Nb phase (zeta phase) or a Ni-Nb solid solution by heat-treatment at 700/sup 0/C. The longer heating time at 400/sup 0/C increased the amount of the Ni-Zr amorphous phase: however, it decreased the reactivity of the amorphous Ni-Zr phase. The same heat-treatment of 400/sup 0/C did not give the considerable change on the amorphous Ni-Nb phase.

  6. A15 superconductors through direct solid-state precipitation: V/sub 3/Ga and Nb/sub 3/Al

    SciTech Connect (OSTI)

    Hong, M.

    1980-09-01T23:59:59.000Z

    A solid-state precipitation process was used to prepare superconducting tapes containing an A15 phase, V/sub 3/Ga or Nb/sub 3/Al, in a ductile niobium or vanadium containing BCC matrix. Ingots weighing as large as 30 to 50 gms of V-(14 approx. 19 at. %) Ga and Nb-(13 approx. 22 at. %) Al were prepared by arc-melting, homogenized, quenched, warm-rolled over 99% into tape, and aged at temperatures in the range 600/sup 0/C to 1000/sup 0/C to precipitate the superconducting A15 phase. The features demonstrated by the process are very attractive for practical applications. In the V-Ga system, transmission electron microscopy (TEM) studies revealed the A15 precipitates in an elongated form. However, for the Nb-Al samples, deformed and aged at 750/sup 0/C, TEM studies revealed A15 precipitation in fine equi-axed particles which formed as a semi-continuous network over sub-grain boundaries formed by the recovery of deformation-induced dislocations. In the V-Ga system, the maximum critical transition temperature (approx. 15 K) was found in materials aged at temperatures of 750/sup 0/C or below. At these aging temperatures the T/sub c/ initially increased with aging time and passed through a distinct maximum. The source of the exceptionally high T/sub c/ is discussed. In the Nb-Al system, the aging response of the T/sub c/ of the tested samples was somewhat different; the T/sub c/ increased with aging time to a plateau, and then increased again to a second plateau. The maximum T/sub c/ measured was approx. 17 K. Promising high-field overall critical currents were obtained in the Nb-Al system (overall J/sub c/ approx. 10/sup 4/ A/cm/sup 2/ in a magnetic field of 140 KG at 4.2 K).

  7. Creep Strength and Microstructure of Al20-25+Nb Alloy Sheets and Foils for Advanced Microturbine Recurperators

    SciTech Connect (OSTI)

    Maziasz, Philip J [ORNL; Shingledecker, John P [ORNL; Evans, Neal D [ORNL; Yamamoto, Yukinori [ORNL; More, Karren Leslie [ORNL; Trejo, Rosa M [ORNL; Lara-Curzio, Edgar [ORNL

    2007-01-01T23:59:59.000Z

    The Oak Ridge National Laboratory (ORNL) and ATI Allegheny Ludlum worked together on a collaborative program for about two years to produce a wide range of commercial sheets and foils of the new AL20-25+Nb{trademark} (AL20-25+Nb) stainless alloy for advanced microturbine recuperator applications. There is a need for cost-effective sheets/foils with more performance and reliability at 650-750 C than 347 stainless steel, particularly for larger 200-250 kW microturbines. Phase 1 of this collaborative program produced the sheets and foils needed for manufacturing brazed plated-fin air cells, while Phase 2 provided foils for primary surface air cells, and did experiments on modified processing designed to change the microstructure of sheets and foils for improved creep-resistance. Phase 1 sheets and foils of AL20-25+Nb have much more creep-resistance than 347 steel at 700-750 C, and those foils are slightly stronger than HR120 and HR230. Results for Phase 2 showed nearly double the creep-rupture life of sheets at 750 C/100 MPa, and similar improvements in foils. Creep data show that Phase 2 foils of AL20-25+Nb alloy have creep resistance approaching that of alloy 625 foils. Testing at about 750 C in flowing turbine exhaust gas for 500 h in the ORNL Recuperator Test Facility shows that foils of AL20-25+Nb alloy have oxidation-resistance similar to HR120 alloy, and much better than 347 steel.

  8. Recent advances in Ti and Nb explosion welding with stainless steel for 2K operating (ILC Program)- To the proceedings of LCWS11

    E-Print Network [OSTI]

    Sabirov, B; Sissakian, A; Shirkov, G; Taran, Yu; Trubnikov, G; Dhanarai, N; Foley, M; Harms, E; Mitchell, D; Nagaitsev, S; Soyars, W; Rybakov, V; Samarokov, Yu; Zhigalov, V; Basti, A; Bedeschi, F

    2012-01-01T23:59:59.000Z

    The world first samples 0f Ti+SS and Nb+SS joints were manufactured by an explosion welding technology demonstrating a high mechanic properties and leak absence at 4.6 x 10^{-9} atm-cc/sec. Residual stresses in bimetallic joints resulting from explosion welding measured by neutron diffraction method are quite high (~1000 MPa). Thermal tempering of explosion welded Ti+SS and Nb+SS specimens leads to complete relaxation of internal stresses in Ti,Nb and Stainless steel and makes the transition elements quite serviceable.

  9. Recent advances in Ti and Nb explosion welding with stainless steel for 2K operating (ILC Program)- To the proceedings of LCWS11

    E-Print Network [OSTI]

    B. Sabirov; J. Budagov; A. Sissakian; G. Shirkov; Yu. Taran; G. Trubnikov; N. Dhanarai; M. Foley; E. Harms; D. Mitchell; S. Nagaitsev; W. Soyars; V. Rybakov; Yu. Samarokov; V. Zhigalov; A. Basti; F. Bedeschi

    2012-01-17T23:59:59.000Z

    The world first samples 0f Ti+SS and Nb+SS joints were manufactured by an explosion welding technology demonstrating a high mechanic properties and leak absence at 4.6 x 10^{-9} atm-cc/sec. Residual stresses in bimetallic joints resulting from explosion welding measured by neutron diffraction method are quite high (~1000 MPa). Thermal tempering of explosion welded Ti+SS and Nb+SS specimens leads to complete relaxation of internal stresses in Ti,Nb and Stainless steel and makes the transition elements quite serviceable.

  10. On the stabilization of A-15 Nb3Ge with high Tc's F. Weiss, O. Demolliens, R. Madar, J. P. Senateur and R. Fruchart

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1137 On the stabilization of A-15 Nb3Ge with high Tc's F. Weiss, O. Demolliens, R. Madar, J. P (Reçu le 21 novembre 1983, accepté le 12 mars 1984) Résumé. 2014 Le composé supraconducteur Nb3Ge de hypothèse selon laquelle le composé Nb3Ge st0153chiométrique de température critique élevée est stabilisé

  11. The Role of tantalum in TiC-WC-TaC-Co sintered carbides. II. influence of tantalum content on the structure and properties of TiC-WC-TaC-Co three-phase sintered carbides

    SciTech Connect (OSTI)

    Cheburaeva, R.F.; Chaporova, I.N.

    1986-10-01T23:59:59.000Z

    This work is devoted to a study of the influence of tantalum on the structure and properties of three-phase alloys. The investigations were made with a constant weight ratio of Ti:WC = 35:65% and an unchanged carbon content. The alloys were prepared by mixing of the (T, W, Ta)C carbides with cobalt and tungsten carbide. The pressed specimens were given a preliminary sinter in hydrogen at 923-973 K and a final one in a vacuum furnace at 1773 K. The microstructure, density, and bend and compressive strengths at room and increased temperatures, coeffiecients of cutting life and strength (in comparison with a standard taken as unity), and adhesion interaction were determined. The coefficient of cutting life was determined by transverse machining of steel. The coefficient of strength was determined by the method of breaking feed in milling of 50 steel with a single-tooth cutter. The adhesion interaction of TiC-WC-TaC-Co alloys with the material being machined (50 steel) was determined in vacuum (which eliminated the additional influence of oxidation of the alloy) at 873 K with a load of 1000N. Tantalum carbide additions have a favorable influence on the physicomechanical and service properties of TiC-WC-Co alloys. Their bend strength at room and increased temperatures increases and there is an increase in the total deformation and the work for deformation at increased temperatures, a reduction in oxidation and adhesion interaction with the material being machined, and a significant increase in wear resistance in cutting. Graphs and tables are included.

  12. Support structure design of the Nb?Sn quadrupole for the high luminosity LHC

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Juchno, M. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Anerella, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ambrosio, G. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Cheng, D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Felice, H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ferracin, P. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Perez, J. C. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Prin, H. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Schmalzle, J. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-06-01T23:59:59.000Z

    New low-? quadrupole magnets are being developed within the scope of the High Luminosity LHC (HL-LHC) project in collaboration with the US LARP program. The aim of the HLLHC project is to study and implement machine upgrades necessary for increasing the luminosity of the LHC. The new quadrupoles, which are based on the Nb?Sn superconducting technology, will be installed in the LHC Interaction Regions and will have to generate a gradient of 140 T/m in a coil aperture of 150 mm. In this paper, we describe the design of the short model magnet support structure and discuss results of the detailed 3D numerical analysis performed in preparation for the first short model test.

  13. Support structure design of the Nb?Sn quadrupole for the high luminosity LHC

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Juchno, M.; Anerella, M.; Ambrosio, G.; Cheng, D.; Felice, H.; Ferracin, P.; Perez, J. C.; Prin, H.; Schmalzle, J.

    2015-06-01T23:59:59.000Z

    New low-? quadrupole magnets are being developed within the scope of the High Luminosity LHC (HL-LHC) project in collaboration with the US LARP program. The aim of the HLLHC project is to study and implement machine upgrades necessary for increasing the luminosity of the LHC. The new quadrupoles, which are based on the Nb?Sn superconducting technology, will be installed in the LHC Interaction Regions and will have to generate a gradient of 140 T/m in a coil aperture of 150 mm. In this paper, we describe the design of the short model magnet support structure and discuss results of themore »detailed 3D numerical analysis performed in preparation for the first short model test.« less

  14. Characterization of Large Grain Nb Ingot Microstructure Using EBSP Mapping and Laue Camera Methods

    SciTech Connect (OSTI)

    Kang Di; Baars, Derek C.; Bieler, Thomas R. [Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824 (United States); Compton, Chris C. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States)

    2011-03-31T23:59:59.000Z

    Large grain/single crystal Nb is currently being examined for fabricating superconducting radiofrequency (SRF) cavities as an alternative to using rolled sheet. Three ingot slices from different suppliers have been characterized and are compared. It is desirable to know the grain orientations of an ingot slice before fabrication. Characterization of an ingot slice has been done using electron backscattered pattern (EBSP) orientation imaging microscopy (OIM), which requires cutting out pieces from the slice, a destructive technique. Use of a Laue camera allows nondestructive characterization of grain orientations. The OIM method was used to examine ingot slices from CBMM and Ningxia, while the Laue method was used to examine a Heraeus ingot slice. The three ingot slices are compared in terms of their crystal orientations and grain boundary misorientations, indicating no obvious commonalities. The Laue method has practical advantages over OIM for evaluating ingot slices during the manufacturing process.

  15. Low Temperature Age Hardening in U-13 at.% Nb: An Atom Probe Tomography Study

    SciTech Connect (OSTI)

    Clarke, A. J. [Los Alamos National Laboratory (LANL); Field, R. D. [Los Alamos National Laboratory (LANL); Hackenberg, R. E, [Los Alamos National Laboratory (LANL); Thoma, D. J. [Los Alamos National Laboratory (LANL); Brown, D. W. [Los Alamos National Laboratory (LANL); Teter, D. F. [Los Alamos National Laboratory (LANL); Miller, Michael K [ORNL; Russell, Kaye F [ORNL; Edmonds, D. V. [University of Leeds, UK; Beverini, G. [University of Leeds, UK

    2009-01-01T23:59:59.000Z

    Low temperature aging (<350 C) of U-13 at.% Nb martensite results in increased strength levels accompanied by significant ductility loss. To determine the decomposition mechanism(s) responsible for these mechanical property changes, atom probe tomography was used to examine the niobium and impurity distributions after aging at 200 or 300 C for times ranging from 2 h to 70 days. No patterns of niobium or impurity atoms were observed that would indicate segregation to the martensitic twin interfaces, making this hardening mechanism unlikely. Phase separation into roughly equiaxed regions of high and low niobium concentration was clearly observed after aging at 300 C for 70 days. However, only subtle niobium concentration changes were observed after aging at 200 C relative to the as-quenched condition, indicating that conventional phase separation is an unlikely explanation for the dramatic mechanical property changes at 200 C. Therefore, consideration of aging mechanisms other than segregation and phase separation may be warranted.

  16. HD1: Design and Fabrication of a 16 Tesla Nb3Sn DipoleMagnet

    SciTech Connect (OSTI)

    Hafalia, A.R.; Bartlett, S.E.; Capsi, S.; Chiesa, L.; Dietderich,D.R.; Ferracin, P.; Goli, M.; Gourlay, S.A.; Hannaford, C.R.; Highley,H.; Lietzke, A.F.; Liggins, N.; Mattafirri, S.; McInturff, A.D.; Nyman,M.; Sabbi, G.L.; Scanlan, R.M.; Swanson, J.

    2003-11-10T23:59:59.000Z

    The Lawrence Berkeley National Laboratory (LBNL) Superconducting Magnet Group has completed the design, fabrication and test of HD1, a 16 T block-coil dipole magnet. State of the art Nb{sub 3}Sn conductor was wound in double-layer racetrack coils and supported by an iron yoke and a tensioned aluminum shell. In order to prevent conductor movement under magnetic forces up to the design field, a coil pre-stress of 150 MPa was required. To achieve this level without damaging the brittle conductor, the target stress was generated during cool-down to 4.2 K by exploiting the thermal contraction differentials between yoke and shell. Accurate control of the shell tension during assembly was obtained using pressurized bladders and interference load keys. An integrated 3D CAD model was used to optimize magnetic and mechanical design and analysis.

  17. Performance analysis of HD1: a 16 Tesla Nb3Sn dipole Magnet

    SciTech Connect (OSTI)

    Mattafirri, S.; Bartlett, S.E.; Bish, P.A.; Caspi, S.; Dietderich, D.R.; Ferracin, P.; Gourlay, S.A.; Hannaford, C.R.; Hafalia, A.R.; Lau, W.G.; Lietzke, A.F.; McInturff, A.D.; Nyman, M.; Sabbi, G.L.; Scanlan, R.M.

    2005-06-01T23:59:59.000Z

    The Superconducting Magnet Group at Lawrence Berkeley National Laboratory (LBNL) has been developing technology for high field accelerator magnets from brittle conductors. HD1 is a single bore block dipole magnet using two, double-layer Nb{sub 3}Sn flat racetrack coils. The magnet was tested in October 2003 and reached a bore peak field of 16 T (94.5% of short sample). The average quench current plateau appeared to be limited by 'stick slip' conductor motions. Diagnostics recorded quench origins and preload distributions. Cumulative deformation of the mechanical structure has been observed. Quench velocity in different field regions has been measured and compared with model predictions. The results obtained during the HD1 test are presented and discussed.

  18. Shell-Based Support Structures for Nb3Sn Accelerator Quadrupole Magnets

    SciTech Connect (OSTI)

    Ferracin, Paolo

    2008-05-19T23:59:59.000Z

    Shell-based support structures are being fabricated and tested as part of the development of large-aperture Nb{sub 3}Sn superconducting quadrupoles for future upgrades of the LHC Interaction Regions. These structures utilize water pressurized bladders for room-temperature pre-load control, and rely on a pre-tensioned aluminum shell to deliver a substantial part of the coil pre-stress during cool-down. The coil final pre-load is therefore monotonically approached from below, without overstressing the strain-sensitive conductor. This method has been adopted by the US LARP collaboration to test subscale racetrack coils (SQ series), 1 m long cos-theta coils (TQS series), and 4 m long magnets (LRS and LQS series). We present recent progress in the development of shell-based support structures, with a description of the principles of operations and the future plans.

  19. Fabrication and Test Results of a Prototype, Nb3Sn Superconducting Racetrack Dipole Magnet

    SciTech Connect (OSTI)

    Gourlay, S. A.; Chow, K.; Dietderich, D.R.; Gupta, R.; Hannaford, R.; Harnden, W.; Lietzke, A.; McInturff, A.D.; Millos, G.A.; Morrison, L.; Morrison, M.; Scanlan, R.M.

    1998-09-01T23:59:59.000Z

    A prototype, Nb{sub 3}Sn superconducting magnet, utilizing a racetrack coil design has been built and tested. This magnet represents the first step in a recently implemented program to develop a high field, accelerator quality magnet. This magnet was constructed with coils wound from conductor developed for the ITER project, limiting the magnet to a field of 6-7 Tesla. Subsequent magnets in the program will utilize improved conductor, culminating in a magnet design capable of producing fields approaching 15 Tesla. The simple geometry is more suitable for the use of brittle superconductors necessary to eventually reach high field levels. In addition, fewer and simpler parts are used in fabricating these coils compared with the more conventional cosine theta cross section coils. The general fabrication steps, mechanical design and quench performance are discussed.

  20. HD1: Design and Fabrication of a 16 Tesla Nb3Sn Dipole Magnet

    SciTech Connect (OSTI)

    Hafalia, A.R.; Barlett, S.E.; Caspi, S.; Chiesa, L.; Dietderich, D.R.; Ferracin, P.; Goli, M.; Gourlay, S.A.; Hannaford, C.R.; Higley, H.; Lietzke, A.F.; Liggins, N.; Mattafirri, S.; McInturff, A.D.; Myman, M.; Sabbi, G.L.; Scanlan, R.M.; Swanson, J.

    2003-10-01T23:59:59.000Z

    The Lawrence Berkeley National Laboratory (LBNL) Supcrconducting Magnet Group has completed the design, fabrication and tcst of HD1, a 16 T block-coil dipole magnet. State of the art Nb{sub 3}Sn conductor was wound in double-layer racetrack coils and supported by an iron yoke and a tensioned aluminum shell. In order to prevent conductor movement under magnetic forces up to the design field, a coil prestress of 150 MPa was required. To achieve this level without damaging the brittle conductor, the target stress was generated during cool-down to 4.2 K by exploiting the thermal contraction differentials between yoke and shell. Accurate control of the shell tension during assembly was obtained using pressurized bladders and interference load keys. An integrated 3D CAD model was used to optimize magnetic and mechanical design and analysis.

  1. Refereed Publications/Journals Cassidy, T.A., C.P. Paranicas, J.H. Shirley, J.B. Dalton, B.T. Teolis, R.E. Johnson,

    E-Print Network [OSTI]

    Johnson, Robert E.

    .E. Johnson, B.A. Larsen, D.J. Lawrence8, D.J. McComas, E. Möbius1, D.B. Reisenfeld, D. Rodriguez, N.1007/s11214-011-9850-4 (2012). Coates, A.J., A. Wellbrock, G.R. Lewis, C.S. Arridge, F.J. Crary, D

  2. Ge MOS Characteristics with CVD HfO2 Gate Dielectrics and TaN Gate Electrode W. P. Bai*, N. Lu*, J. Liu*, A. Ramirez**, D. L. Kwong*, D. Wristers**, A. Ritenour#

    E-Print Network [OSTI]

    Ge MOS Characteristics with CVD HfO2 Gate Dielectrics and TaN Gate Electrode W. P. Bai*, N. Lu*, J, we report for the first time Ge MOS characteristics with ultra thin rapid thermal CVD HfO2 gate dielectrics and TaN gate electrode. Using the newly developed pre- gate cleaning and NH3-based Ge surface

  3. Two-particle azimuthal correlations in 4.2A GeV C+Ta collisions

    SciTech Connect (OSTI)

    Simic, Lj.; Mendas, I. [Institute of Physics, P.O. Box 68, 11081 Belgrade, Serbia (Serbia and Montenegro); Jotanovic, O. [Faculty of Natural Science, Banja Luka (Bosnia and Herzegowina); Milosevic, J. [Department of Physics, University of Oslo, Oslo (Norway)

    2007-10-15T23:59:59.000Z

    Two particle azimuthal correlations are studied in 4.2A GeV C+Ta collisions observed with the 2-m propane bubble chamber exposed at JINR Dubna Synchrophasotron. The correlations are analyzed both for protons and negative pions, and their dependence on the collision centrality, rapidity and rapidity difference is investigated. It is found that protons show a weak back-to-back correlations, while a side-by-side correlations are observed for negative pions. Restricting both protons to the target or projectile fragmentation region, the side-by-side correlations are observed for protons also. Using the two particle correlation function, the flow analysis is performed and intensity of directed flow is determined without event-by event estimation of the reaction plane.

  4. Ultrafast transmission electron microscopy on dynamic process of a CDW transition in 1T-TaSe2

    E-Print Network [OSTI]

    Sun, Shuaishuai; Li, Zhongwen; Cao, Gaolong; Liu, Y; Lu, W J; Sun, Y P; Tian, Huanfang; HuaixinYang,; Li, Jianqi

    2015-01-01T23:59:59.000Z

    Four-dimensional ultrafast transmission electron microscopy (4D-UTEM) measurements reveal a rich variety of structural dynamic phenomena at a phase transition in the charge-density-wave (CDW) 1T-TaSe2. Through the photoexcitation, remarkable changes on both the CDW intensity and orientation are clearly observed associated with the transformation from a commensurate (C) into an incommensurate (IC) phase in a time-scale of about 3 ps. Moreover, the transient states show up a notable "structurally isosbestic point" at a wave vector of qiso where the C and IC phases yield their diffracting efficiencies in an equally ratio. This fact demonstrates that the crystal planes parallel to qiso adopts visibly common structural features in these two CDW phases. The second-order characters observed in this nonequilibrium phase transition have been also analyzed based on the time-resolved structural data.

  5. Building America Case Study: Ground Source Heat Pump Research, TaC Studios Residence, Atlanta, Georigia (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2014-09-01T23:59:59.000Z

    As part of the NAHB Research Center Industry Partnership, Southface partnered with TaC Studios, an Atlanta based architecture firm specializing in residential and light commercial design, on the construction of a new test home in Atlanta, GA in the mixed-humid climate. This home serves as a residence and home office for the firm's owners, as well as a demonstration of their design approach to potential and current clients. Southface believes the home demonstrates current best practices for the mixed-humid climate, including a building envelope featuring advanced air sealing details and low density spray foam insulation, glazing that exceeds ENERGY STAR requirements, and a high performance heating and cooling system. Construction quality and execution was a high priority for TaC Studios and was ensured by a third party review process. Post construction testing showed that the project met stated goals for envelope performance, an air infiltration rate of 2.15 ACH50. The homeowner's wished to further validate whole house energy savings through the project's involvement with Building America and this long-term monitoring effort. As a Building America test home, this home was evaluated to detail whole house energy use, end use loads, and the efficiency and operation of the ground source heat pump and associated systems. Given that the home includes many non-typical end use loads including a home office, pool, landscape water feature, and other luxury features not accounted for in Building America modeling tools, these end uses were separately monitored to determine their impact on overall energy consumption.

  6. Activation cross sections of $?$-particle induced nuclear reactions on hafnium and deuteron induced nuclear reaction on tantalum: production of $^{178}$W/$^{178m}$Ta generator

    E-Print Network [OSTI]

    F. Tárk'anyi; S. Tak'acs; F. Ditrói; A. Hermanne; A. V. Ignatyuk; M. S. Uddin

    2014-12-01T23:59:59.000Z

    In the frame of a systematic study of charged particle production routes of medically relevant radionuclei, the excitation function for indirect production of $^{178m}$Ta through $^{nat}$Hf($\\alpha$,xn)$^{178}$W-$^{178m}$Ta nuclear reaction was measured for the first time up to 40 MeV. In parallel, the side reactions $^{nat}$Hf($\\alpha$,x)$^{179,177,176,175}$W, $^{183,182,178g,177,176,175}$Ta, $^{179m,177m,175}$Hf were also assessed. Stacked foil irradiation technique and $\\gamma$-ray spectrometry were used. New experimental cross section data for the $^{nat}$Ta(d,xn)$^{178}$W reaction are also reported up to 40 MeV. The measured excitation functions are compared with the results of the ALICE-IPPE, and EMPIRE nuclear reaction model codes and with the TALYS 1.4 based data in the TENDL-2013 library. The thick target yields were deduced and compared with yields of other charged particle ((p,4n), (d,5n) and ($^3$He,x)) production routes for $^{178}$W.

  7. Synthesis, Exfoliation, and Electronic/Protonic Conductivity of the Dion-Jacobson Phase Layer Perovskite HLa2TiTa2O10

    E-Print Network [OSTI]

    Synthesis, Exfoliation, and Electronic/Protonic Conductivity of the Dion-Jacobson Phase Layer-based method. When prepared by the precursor method, HLa2Ti2TaO10·nH2O (n = 1-2) could be exfoliated

  8. Proton-Conducting Films of Nanoscale Ribbons Formed by Exfoliation of the Layer Perovskite H2SrTa2O7

    E-Print Network [OSTI]

    Proton-Conducting Films of Nanoscale Ribbons Formed by Exfoliation of the Layer Perovskite H2SrTa2OTa2O7 were grown and characterized as solid-state proton conductors. The ribbons, made by exfoliation membranes made from layered materials such as exfoliated zirconium phosphate.12 Unfortunately, the proton

  9. R E S E A R C H L E T T E R Toxin^antitoxin (TA) systems are prevalent and transcribed

    E-Print Network [OSTI]

    Hergenrother, Paul J.

    problematic hospital and community- acquired pathogens are methicillin-resistant Staphylococcus aureus (MRSA bacteria; however, the prevalence and identity of TA systems in clinical isolates of MRSA and PA has not been defined. We isolated DNA from 78 MRSA and 42 PA clinical isolates and used PCR to probe

  10. Skewon-Axion Medium and Soft-and-Hard/DB Boundary Condition

    E-Print Network [OSTI]

    Ismo V. Lindell; Ari Sihvola

    2012-01-20T23:59:59.000Z

    The class of skewon-axion media can be defined in a simple and natural manner applying four-dimensional differential-form representation of electromagnetic fields and media. It has been recently shown that an interface of a uniaxial skewon-axion medium acts as a DB boundary requiring vanishing normal components of the D and B vectors. In the present paper a more general skewon-axion medium is considered. It is shown that a planar interface of such a medium acts as a boundary generalizing both soft-and-hard (SH) and DB boundary conditions to SHDB conditions. Reflection of a plane wave from a planar SHDB boundary is studied. It is shown that for the two eigenpolarizations the boundary can be replaced by equivalent PEC or PMC boundaries. The theory is tested with a numerical example.

  11. 6494 J. Phys. Chem. 1989, 93, 6494-6501 Comparative Cluster Reaction Studies of the V, Nb, and l a Series

    E-Print Network [OSTI]

    Morse, Michael D.

    transition-metal clusters (V,, Nb,, and Tan)have been investigated in the gas phase by using a fast-flow chemical reactor. Dissociative chemisorptionof D2and N2is found to be sizeselectivefor these bare metal

  12. Stabilization of ordered zirconium titanates through the chemical substitution of Ti[sup 4+] by Al[sup 3+]/Ta[sup 5+

    SciTech Connect (OSTI)

    Zhang, Yan; Davies, P.K. (Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Materials Science and Engineering)

    1994-03-01T23:59:59.000Z

    The authors have investigated the ZrO[sub 2]-AlTaO[sub 4] system to understand how selected chemical substitutions can be used to control cation-ordering transformations in zirconium titanate based dielectric ceramics. The complete replacement of the Ti content of Zr[sub x]Ti[sub 2[minus]x]O[sub 4] by a coupled Al[sup 3+]/Ta[sup 5+] substitution permits the synthesis of a wide range of isostructural Zr[sub x](Al[sub 0.5]Ta[sub 0.5])[sub 2[minus]x] solid solutions. At high temperatures a disordered [alpha]-PbO[sub 2] type of structure is formed for 0.375 [le] x [le] 1.03. Samples with 0.67 [le] x [le] 1.03 undergo a cation-ordering reaction to a structure in which the a and b axes of the parent disordered cell are doubled. The stabilities of these cation-ordered derivative structures are significantly greater than those of the ordered zirconium titanates. The ordering temperatures are composition dependent with a maximum of 1,393 C occurring for Zr[sub 0.86](Al[sub 0.5]Ta[sub 0.5])[sub 1.14]O[sub 4]. The higher transition temperatures also enhance the kinetics of the ordering transition; whereas the pure zirconium titanates require extended annealing to produce complete cation order, fully ordered Zr[sub x](Al[sub 0.5]Ta[sub 0.5])[sub 2[minus]x]O[sub 4] solid solutions are produced during a normal furnace cool.

  13. Construction challenges and solutions in TAMU3, a 14 T stress-managed Nb{sub 3}Sn dipole

    SciTech Connect (OSTI)

    Holik, E. F.; Garrison, R.; Diaczenko, N.; Elliott, T.; Jaisle, A.; McInturff, A. D.; McIntyre, P.; Sattarov, A. [Texas A and M University 3380 University Drive East College Station, Texas, 77843 (United States)

    2014-01-29T23:59:59.000Z

    The Accelerator Research Laboratory at Texas A and M University is nearing completion of a Nb{sub 3}Sn dipole that incorporates stress management directly in its windings. The windings utilize graded-cross-section cable made from 54/61 (54 out of a 61 subelement hexagonal pattern) Restacked Rod Processed® Nb{sub 3}Sn/Cu conductor and fine-filament S-2 glass fabric insulation. Coil heat treatment and associated differential expansions have brought about some tin leakage, highresistance electrical shorts, and coil gaps. TAMU3b impregnation successfully increased the coil-to-ground resistance. Quench protection in TAMU3 was simulated using QUENCH. The tests of TAMU3 should provide the first examination of stress management at field intensities greater than 12 T.

  14. Test Results of LARP Nb3Sn Quadrupole Magnets Using a Shell-based Support Structure (TQS)

    SciTech Connect (OSTI)

    Caspi, S.; Dietderich, D. R.; Felice, H.; Ferracin, P.; Hafalia, R.; Hannaford, C. R.; Lietzke, A. F.; Lizarazo, J.; Sabbi, G.; Wang, X.; Ghosh, A.; Wanderer, P.; Ambrosio, G.; Barzi, E.; Bossert, R.; Chlachidze, G.; Feher, S.; Kashikhin, V. V.; Lamm, M.; Tartaglia, M. A.; Zlobin, A. V.; Bajko, M.; Bordini, B.; DeRijk, G.; Giloux, C.; Karppinen, M.; Perez, J. C.; Rossi, L.; Siemko, A.; Todesco, E.

    2008-08-17T23:59:59.000Z

    Among the magnet development program of a large-aperture Nb{sub 3}Sn superconducting quadrupole for the Large Hadron Collider luminosity upgrade, six quadrupole magnets were built and tested using a shell based key and bladder technology (TQS). The 1 m long 90 mm aperture magnets are part o fthe US LHC Accelerator Research Program (LARP) aimed at demonstrating Nb{sub 3}Sn technology by the year 2009, of a 3.6 m long magnet capable of achieving 200 T/m. In support of the LARP program the TQS magnets were tested at three different laboratories, LBNL, FNAL and CERN and while at CERN a technology-transfer and a four days magnet disassembly and reassembly were included. This paper summarizes the fabrication, assembly, cool-down and test results of the six magnets and compres measruements with design expectations.

  15. Nonlinear transport in quasi-one-dimensional Nb{sub 2}PdS{sub 5} nanowires

    SciTech Connect (OSTI)

    Ning, Wei; Yu, Hongyan; Wang, Ning; Han, Yuyan; Yang, Jiyong; Du, Haifeng; Zhang, Changjin [High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, Anhui (China); Liu, Yequn [Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Yang, Kun [National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306-4005 (United States); Tian, Mingliang, E-mail: tianml@hmfl.ac.cn; Zhang, Yuheng [High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, Anhui (China); Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093 (China)

    2014-10-27T23:59:59.000Z

    Nb{sub 2}PdS{sub 5} is a newly discovered quasi-one-dimensional (quasi-1D) superconductor with a high upper critical field along the chain direction. Here, we report the size-dependent electronic properties of Nb{sub 2}PdS{sub 5} nanowires obtained by ultrasonically cleaving the bulk crystals. The nanowires exhibit a superconductor to insulator transition as the cross-sectional area decreases. Moreover, for the thinner nanowires with insulating state, the transport properties exhibit a power-law dependence on both temperature and bias voltage at an intermediate temperature (<30?K), followed by a conduction saturation below 10?K. We found that such an apparent power-law behavior can be described by the extended variable range hopping theory developed recently for the multichannel quasi-1D systems, where the localization of electrons is expected to be dominant instead of the Luttinger liquid nature.

  16. Characterization of Nb coating in HIE-ISOLDE QWR superconducting accelerating cavities by means of SEM-FIB and TEM

    E-Print Network [OSTI]

    Bartova, Barbora; Taborelli, M; Aebersold, A B; Alexander, D T L; Cantoni, M; Calatroni, Sergio; CERN. Geneva. ATS Department

    2015-01-01T23:59:59.000Z

    The Quarter Wave Resonators (QWR) high-? cavities (0.3 m diameter and 0.9 m height) are made from OFE 3D-forged copper and are coated by DC-bias diode sputtering with a thin superconducting layer of niobium. The Nb film thickness, morphology, purity and quality are critical parameters for RF performances of the cavity. They have been investigated in a detailed material study.

  17. Diffusion Barrier Selection from Refractory Metals (Zr, Mo and Nb) via Interdiffusion Investigation for U-Mo RERTR Fuel Alloy

    SciTech Connect (OSTI)

    K. Huang; C. Kammerer; D. D. Keiser, Jr.; Y. H. Sohn

    2014-04-01T23:59:59.000Z

    U-Mo alloys are being developed as low enrichment monolithic fuel under the Reduced Enrichment for Research and Test Reactor (RERTR) Program. Diffusional interactions between the U-Mo fuel alloy and Al-alloy cladding within the monolithic fuel plate construct necessitate incorporation of a barrier layer. Fundamentally, a diffusion barrier candidate must have good thermal conductivity, high melting point, minimal metallurgical interaction, and good irradiation performance. Refractory metals, Zr, Mo, and Nb are considered based on their physical properties, and the diffusion behavior must be carefully examined first with U-Mo fuel alloy. Solid-to-solid U-10wt.%Mo vs. Mo, Zr, or Nb diffusion couples were assembled and annealed at 600, 700, 800, 900 and 1000 degrees C for various times. The interdiffusion microstructures and chemical composition were examined via scanning electron microscopy and electron probe microanalysis, respectively. For all three systems, the growth rate of interdiffusion zone were calculated at 1000, 900 and 800 degrees C under the assumption of parabolic growth, and calculated for lower temperature of 700, 600 and 500 degrees C according to Arrhenius relationship. The growth rate was determined to be about 10 3 times slower for Zr, 10 5 times slower for Mo and 10 6 times slower for Nb, than the growth rates reported for the interaction between the U-Mo fuel alloy and pure Al or Al-Si cladding alloys. Zr, however was selected as the barrier metal due to a concern for thermo- mechanical behavior of UMo/Nb interface observed from diffusion couples, and for ductile-to-brittle transition of Mo near room temperature.

  18. Investigation of (110)Mo, (110)W monocrystals and Nb polycrystal implanted by oxygen ions and used as TEC electrodes

    SciTech Connect (OSTI)

    Tsakadze, L.M.

    1995-12-31T23:59:59.000Z

    In an effort to improve efficiency of a thermionic energy converter (TEC), converting thermal power into electric power, there were investigated collectors made of (110)Mo and (110)W monocrystals, and Nb polycrystal, all being implanted by oxygen ions with fluence of 1*10{sup 18} cm{sup {minus}2}. For emitters there were used (110)Mo and (110)W monocrystals, and Nb polycrystal implanted by oxygen ions, respectively. The performance of TEC with implanted electrode material is compared with this of TEC having electrodes of non-implanted materials. It is demonstrated that for emitter temperature range of 1,473 to 1,873 K employment of (110)Mo and (110)W monocrystals, implanted by oxygen ions, for TEC collector allows to increase the specific output power of a converter approximately by a factor of 1.6, and employment of implanted Nb for electrodes -- to increase this value approximately by a factor of 3, as compared with non-implanted electrode materials. The upgraded performance of TEC with implanted electrode materials is caused by the increase of minimum values of the collector working function by {approximately}0.15--0.2 eV as compared with non-implanted collectors, as well as by improvement of emitter emissive and adsorption properties due to oxygen supply from collectors at operating temperatures.

  19. Magneto thermal conductivity of superconducting Nb with intermediate level of impurity

    SciTech Connect (OSTI)

    L.S. Sharath Chandra, M.K. Chattopadhyay, S.B. Roy, V.C. Sahni, G.R. Myneni

    2012-03-01T23:59:59.000Z

    Niobium materials with intermediate purity level are used for fabrication of superconducting radio frequency cavities (SCRF), and thermal conductivity is an important parameter influencing the performance of such SCRF cavities. We report here the temperature and magnetic field dependence of thermal conductivity {kappa} for superconducting niobium (Nb) samples, for which the electron mean free path I{sub e}, the phonon mean free path I{sub g}, and the vortex core diameter 2r{sub C} are of the same order of magnitude. The measured thermal conductivity is analyzed using the effective gap model (developed for I{sub e} >> 2r{sub C} (Dubeck et al 1963 Phys. Rev. Lett. 10 98)) and the normal core model (developed for I{sub e} << 2r{sub C} (Ward and Dew-Hughes 1970 J. Phys. C: Solid St. Phys. 3 2245)). However, it is found that the effective gap model is not suitable for low temperatures when I{sub e} {approx} 2r{sub C}. The normal core model, on the other hand, is able to describe {kappa}(T,H) over the entire temperature range except in the field regime between H{sub C1} and H{sub C2} i.e. in the mixed state. It is shown that to understand the complete behavior of {kappa} in the mixed state, the scattering of quasi-particles from the vortex cores and the intervortex quasi-particle tunneling are to be invoked. The quasi-particle scattering from vortices for the present system is understood in terms of the framework of Sergeenkov and Ausloos (1995 Phys. Rev. B 52 3614) extending their approach to the case of Nb. The intervortex tunneling is understood within the framework of Schmidbauer et al (1970 Z. Phys. 240 30). Analysis of the field dependence of thermal conductivity shows that while the quasi-particle scattering from vortices dominates in the low fields, the intervortex quasi-particle tunneling dominates in high fields. Analysis of the temperature dependence of thermal conductivity shows that while the quasi-particle scattering is dominant at low temperatures, the intervortex quasi-particle tunneling is dominant at high temperatures.

  20. Analysis Of Post-Wet-Chemistry Heat Treatment Effects On Nb SRF Surface Resistance

    SciTech Connect (OSTI)

    Dhakal, Pashupati; Ciovati, Gianluigi; Kneisel, Peter K.; Myneni, Ganapati Rao

    2014-02-01T23:59:59.000Z

    Most of the current research in superconducting radio frequency (SRF) cavities is focused on ways to reduce the construction and operating cost of SRF-based accelerators as well as on the development of new or improved cavity processing techniques. The increase in quality factors is the result of the reduction of the surface resistance of the materials. A recent test on a 1.5 GHz single cell cavity made from ingot niobium of medium purity and heat treated at 1400 deg C in a ultra-high vacuum induction furnace resulted in a residual resistance of ~ 1n{Omega} and a quality factor at 2.0 K increasing with field up to ~ 5×10{sup 10} at a peak magnetic field of 90 mT. In this contribution, we present some results on the investigation of the origin of the extended Q{sub 0}-increase, obtained by multiple HF rinses, oxypolishing and heat treatment of ?all Nb? cavities.

  1. Deformation of the UI-14at%Nb shape memory alloy: experiments and modeling

    SciTech Connect (OSTI)

    Field, Robert D [Los Alamos National Laboratory; Tome, Carlos N [Los Alamos National Laboratory; Mc Cabe, Rodney J [Los Alamos National Laboratory; Clarke, Amy J [Los Alamos National Laboratory; Brown, Donald W [Los Alamos National Laboratory; Tupper, Catherine N [Los Alamos National Laboratory

    2010-12-22T23:59:59.000Z

    U-14at%Nb is a shape memory effect (SME) alloy that undergoes deformation by the motion of complex twins and twin related lath boundaries up to the limit of SME deformation ({approx}7%). All of the twins present in the as-transformed martensite and active during SME deformation are derived from those of the orthorhombic alpha-U phase, modified for the monoclinic distortion of the alpha martensite phase. In the SME regime a simple Bain strain model qualitatively predicts variant selection, texture development in polycrystalline samples, and stress-strain behavior as a function of parent phase orientation in single crystal micropillars. In the post-SME regime, unrecoverable deformation occurs by a combination of slip and twinning, with the first few percent of strain in tension apparently governed by a twin species specifically associated with the monoclinic distortion (i.e. not present in the orthorhombic alpha-U phase). The situation in compression is more complicated, with a combination of slip and twinning systems believed responsible for deformation. A review of the Bain strain model for SME deformation will be presented in conjunction with experimental data. In addition, results from modeling of post-SME behavior using the Visco-Plastic Self-Consistent (VPSC) model will be compared to experimental texture measurements.

  2. Test Results for HD1, a 16 Tesla Nb3Sn Dipole Magnet

    SciTech Connect (OSTI)

    Lietzke, A.F.; Bartlett, S.; Bish, P.; Caspi, S.; Chiesa, L.; Dietderich, D.; Ferracin, P.; Gourlay, S.A.; Goli, M.; Hafalia, R.R.; Higley, H.; Hannaford, R.; Lau, W.; Liggens, N.; Mattafirri, S.; McInturff, A.; Nyman, M.; Sabbi, G.; Scanlan, R.; Swanson, J.

    2003-10-01T23:59:59.000Z

    The Superconducting Magnet Group at Lawrence Berkeley National Laboratory has been developing the technology for using brittle superconductor in high-field accelerator magnets. HD1, the latest in a series of magnets, contains two, double-layer Nb{sub 3}Sn flat racetrack coils. This single-bore dipole configuration, using the highest performance conductor available, was designed and assembled for a 16 tesla conductor/structure/pre-stress proof-of-principle. With the combination of brittle conductor and high Lorentz stress, considerable care was taken to predict the magnet's mechanical responses to pre-stress, cool-down, and excitation. Subsequent cold testing satisfied expectations: Training started at 13.6 T, 83% of 'short-sample', achieved 90% in 10 quenches, and reached its peak bore field (16 T) after 19 quenches. The average plateau, {approx}92% of 'short-sample', appeared to be limited by 'stick-slip' conductor motions, consistent with the 16.2 T conductor 'lift-off' pre-stress that was chosen for this first test. Some lessons learned and some implications for future conductor and magnet technology development are presented and discussed.

  3. Assembly and Tests of SQ02, a Nb3Sn Racetrack Quadrupole Magnet for LARP

    SciTech Connect (OSTI)

    Ferracin, Paolo; Ambrosio, G.; Barzi, E.; Caspi, S.; Dietderich, D.R.; Feher, S.; Gourlay, S.A.; Hafalia, A.R.; Hannaford, C.R.; Lizarazo, J.; Lietzke, A.F.; McInturff, A.D.; Sabbi, G.L.; Zlobin, A.V.

    2007-06-01T23:59:59.000Z

    The US LHC Accelerator Research Program (LARP) consists of four US laboratories (BNL, FNAL, LBNL, and SLAC) collaborating with CERN to achieve a successful commissioning of the LHC and to develop the next generation of Interaction Region magnets. In 2004, a large aperture Nb{sub 3}Sn racetrack quadrupole magnet (SQ01) has been fabricated and tested at LBNL. The magnet utilized four subscale racetrack coils and was instrumented with strain gauges on the support structure and directly over the coil's turns. SQ01 exhibited training quenches in two of the four coils and reached a peak field in the conductor of 10.4 T at a current of 10.6 kA. After the test, the magnet was disassembled, inspected with pressure indicating films, and reassembled with minor modifications. A second test (SQ01b) was performed at FNAL and included training studies, strain gauge measurements and magnetic measurements. Magnet inspection, test results, and magnetic measurements are reported and discussed, and a comparison between strain gauge measurements and 3D finite element computations is presented.

  4. Recent Test Results of the High Field Nb3Sn Dipole Magnet HD2

    SciTech Connect (OSTI)

    Ferracin, P.; Bingham, B.; Caspi, S.; Cheng, D. W.; Dietderich, D. R.; Felice, H.; Hafalia, A. R.; Hannaford, C. R.; Joseph, J.; Lietzke, A. F.; Lizarazo, J.; Sabbi, G.; Wang, X.

    2009-10-19T23:59:59.000Z

    The 1 m long Nb{sub 3}Sn dipole magnet HD2, fabricated and tested at Lawrence Berkeley National Laboratory, represents a step towards the development of block-type accelerator quality magnets operating in the range of 13-15 T. The magnet design features two coil modules composed of two layers wound around a titanium-alloy pole. The layer 1 pole includes a round cutout to provide room for a bore tube with a clear aperture of 36 mm. After a first series of tests where HD2 reached a maximum bore field of 13.8 T, corresponding to an estimated peak field on the conductor of 14.5 T, the magnet was disassembled and reloaded without the bore tube and with a clear aperture increased to 43 mm. We describe in this paper the magnet training observed in two consecutive tests after the removal of the bore tube, with a comparison of the quench performance with respect to the previous tests. An analysis of the voltage signals recorded before and after training quenches is then presented and discussed, and the results of coil visual inspections reported.

  5. Fabrication and test of a racetrack magnet using pre-reacted Nb3Sn cable

    SciTech Connect (OSTI)

    Giorgio Ambrosio et al.

    2002-12-11T23:59:59.000Z

    A racetrack magnet, using Nb{sub 3}Sn superconducting cable reacted before winding, has been fabricated and tested at Fermilab. It consists of two flat racetrack coils, connected in a common-coil configuration, separated by a 5 mm thick fiberglass plate. Synthetic oil was used to prevent sintering of the strands during the heat treatment. The coils were wound and vacuum impregnated in the mechanical structure. The turn-to-turn insulation, consisting of Kapton{reg_sign}and pre-impregnated fiberglass tapes as wide as the cable, was wound together with the bare cable in order to form a continuous inter-turn spacer. The coils were instrumented with voltage taps, temperature sensors, spot heaters and quench heaters. The maximum current achieved was 12675 A which is 78% of the short sample limit at 5.1 K (minimum temperature in the coil during 75 A/s ramp). Measurement of the temperature margin revealed a low degradation in the innermost turns. Quench performances at different temperatures and ramp rate effects have been measured and are presented and discussed.

  6. Critical Current Test Facilities for LHC Superconducting NbTi Cable Strands

    E-Print Network [OSTI]

    Boutboul, T; Denarié, C H; Oberli, L R; Richter, D

    2001-01-01T23:59:59.000Z

    The Rutherford-type superconducting Cu/NbTi cables of the LHC accelerator are currently mass-produced by a few industrial firms. As a part of the acceptance tests, the critical current of superconducting multifilamentary wires is systematically measured on virgin strands to qualify the wires and on extracted strands to qualify the cables. For this purpose, four test stations are in operation at CERN to measure the critical current of strands at both 4.2 K and 1.9 K in magnetic fields in the 6-11 T range. The measurement setup and procedures of these facilities are reported in this article. The quality of the critical current test is guaranteed by supervising the SPC (Statistical Process Control) charts of a reference sample. The measurement repeatability and reproducibility of the stations are found to be excellent. Moreover, the measured critical current of a strand is found to be almost independent of the test station in which the measurement is performed.

  7. The SMC (Short Model Coil) Nb3Sn Program: FE Analysis with 3D Modeling

    E-Print Network [OSTI]

    Kokkinos, C; Guinchard, M; Karppinen, M; Manil, P; Perez, J C; Regis, F

    2012-01-01T23:59:59.000Z

    The SMC (Short Model Coil) project aims at testing superconducting coils in racetrack configuration, wound with Nb3Sn cable. The degradation of the magnetic properties of the cable is studied by applying different levels of pre-stress. It is an essential step in the validation of procedures for the construction of superconducting magnets with high performance conductor. Two SMC assemblies have been completed and cold tested in the frame of a European collaboration between CEA (FR), CERN and STFC (UK), with the technical support from LBNL (US). The second assembly showed remarkable good quench results, reaching a peak field of 12.5T. This paper details the new 3D modeling method of the SMC, implemented using the ANSYS® Workbench environment. Advanced computer-aided-design (CAD) tools are combined with multi-physics Finite Element Analyses (FEA), in the same integrated graphic interface, forming a fully parametric model that enables simulation driven development of the SMC project. The magnetic and structural ...

  8. The use of 2,4-DB as a selective herbicide for broadleaf weed control in peanuts

    E-Print Network [OSTI]

    Ketchersid, Mary Lou

    1976-01-01T23:59:59.000Z

    LW ? 2, 4-DB ~ ~ ~ ? - ? ~ LW ? 2, 4-D ce 0 0? 0 4 5 C 7 H 100? 50- io 2, 4- DB 2& 4-D o 4 5' F& %coke after Tr eirtrce. t. Fi ocr e 5. Patter a of !"ct"' o I! ie 2, 4 ? D bu. 'ic. roc i ~ 1oef;. ae!! (LW) ead tre rted 1 eef (T' ) e... An analytical procedur e wes developed to analyze fre h plant material and nuts for 2, 4-DB (4-(2, 4-dich) oropher oxy)butyr'c acid) and its metabolite 2, 4-D ((2, t-dxchlorophenoxy)acetic acid. ':. Wh. Ppl 5 t-"r. s . d e pr . st. a, A h ~t: . , I, . i t. 6...

  9. Page 6 T H E E N V I R O N M E N TA L F O R U M Managing Water Demand

    E-Print Network [OSTI]

    Shapiro, Benjamin

    as structural solutions, more emphasis on demand-side as well as supply-side management techniques, and a growPage 6 T H E E N V I R O N M E N TA L F O R U M Managing Water Demand: Price vs. Non-price demand management tech- niques." These would include actions such as requiring low-flow fixtures

  10. Preliminary plans to move the special nuclear material supporting category I and II missions from TA-18 to the device assembly facility

    SciTech Connect (OSTI)

    Haag, William Earl; Nicholas, N. J. (Nancy J.); Mann, P. (Paul)

    2004-01-01T23:59:59.000Z

    In December 2002, the National Nuclear Security Agency (NNSA) issued a Record of Decision announcing its intent to relocate safeguards Category I and II missions and associated special nuclear materials (SNM) from Los Alamos National Laboratory (LANL) Technical Area 18 (TA-18) to the Device Assembly Facility (DAF) at the Nevada Test Site (NTS). The Cat I and II missions support nuclear criticality safety, nuclear emergency response, nuclear nonproliferation, and homeland security. TA-18 is the sole remaining facility in the United States with the capability to perform general-purpose nuclear materials handling experiments and training. Hands-on and remote control experiments, measurements, and training with special materials and devices are conducted. The conceptual design for modifying the DAF to house these Cat I and II missions includes plans for packaging and transporting the SNM inventory associated with the missions. This paper discusses these preliminary packaging and transporting plans, including how they fit into the plans for transitioning the relevant TA- 18 missions to DAF while ensuring that mission, cost, and schedule requirements are met.

  11. Implementing waste minimization at an active plutonium processing facility: Successes and progress at technical area (TA) -55 of the Los Alamos National Laboratory

    SciTech Connect (OSTI)

    Balkey, J.J.; Robinson, M.A.; Boak, J.

    1997-12-01T23:59:59.000Z

    The Los Alamos National Laboratory has ongoing national security missions that necessitate increased plutonium processing. The bulk of this activity occurs at Technical Area -55 (TA-55), the nations only operable plutonium facility. TA-55 has developed and demonstrated a number of technologies that significantly minimize waste generation in plutonium processing (supercritical CO{sub 2}, Mg(OH){sub 2} precipitation, supercritical H{sub 2}O oxidation, WAND), disposition of excess fissile materials (hydride-dehydride, electrolytic decontamination), disposition of historical waste inventories (salt distillation), and Decontamination & Decommissioning (D&D) of closed nuclear facilities (electrolytic decontamination). Furthermore, TA-55 is in the process of developing additional waste minimization technologies (molten salt oxidation, nitric acid recycle, americium extraction) that will significantly reduce ongoing waste generation rates and allow volume reduction of existing waste streams. Cost savings from reduction in waste volumes to be managed and disposed far exceed development and deployment costs in every case. Waste minimization is also important because it reduces occupational exposure to ionizing radiation, risks of transportation accidents, and transfer of burdens from current nuclear operations to future generations.

  12. Magnetic ordering of divalent europium in double perovskites Eu{sub 2}LnTaO{sub 6} (Ln=rare earths)

    SciTech Connect (OSTI)

    Misawa, Yoshitaka; Doi, Yoshihiro [Division of Chemistry, Hokkaido University, Sapporo 060-0810 (Japan); Hinatsu, Yukio, E-mail: hinatsu@sci.hokudai.ac.jp [Division of Chemistry, Hokkaido University, Sapporo 060-0810 (Japan)

    2011-06-15T23:59:59.000Z

    Structures and magnetic properties of double perovskite-type oxides Eu{sub 2}LnTaO{sub 6} (Ln=Eu, Dy-Lu) were investigated. These compounds adopt a distorted double perovskite structure with space group P2{sub 1}/n. Magnetic susceptibility, specific heat, and {sup 151}Eu Moessbauer spectrum measurements show that the Eu{sup 2+} ions at the 12-coordinate sites of the perovskite structure are antiferromagnetically ordered at {approx}4 K, and that Ln{sup 3+} ions at the 6-coordinate site are in the paramagnetic state down to 1.8 K. - Graphical abstract: Magnetic properties of double perovskite-type oxides Eu{sub 2}LnTaO{sub 6} (Ln=Eu, Dy-Lu) were investigated. Magnetic susceptibility, specific heat, and {sup 151}Eu Moessbauer spectrum measurements show that the Eu{sup 2+} ions at the 12-coordinate sites of the perovskite structure are antiferromagnetically ordered at {approx}4 K. Highlights: > Crystal structures of double perovskites Eu{sub 2}LnTaO{sub 6} (Ln=rare earth) were determined. > We found that these compounds show an antiferromagnetic ordering at {approx}4 K. > The magnetic ordering is due to the interactions of Eu{sup 2+} ions. > It was elucidated by specific heat and {sup 151}Eu Moessbauer spectrum measurements.

  13. C O N TA C T > Lee Ann Ciarlette | 630.252.4835 | leeann@anl.gov | Nuclear Engineering Division | students.ne.anl.gov Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439 November 2012

    E-Print Network [OSTI]

    Kemner, Ken

    C O N TA C T > Lee Ann Ciarlette | 630.252.4835 | leeann@anl.gov | Nuclear Engineering Division of Massachuse s Lowell · University of Michigan · University of Michigan, Ann Arbor · University of Missouri

  14. Synthesis, crystal structure, spectroscopic and thermal properties of [Et{sub 4}N][Ta{sub 6}Br{sub 12}(H{sub 2}O){sub 6}]Br{sub 4}.4H{sub 2}O (Et=ethyl)-A new compound with the paramagnetic [Ta{sub 6}Br{sub 12}]{sup 3+} cluster core

    SciTech Connect (OSTI)

    Peric, Berislav, E-mail: bperic@irb.h [Ruder Boskovic Institute, Bijenicka cesta 54, 10000 Zagreb (Croatia); Jozic, Drazan [Ruder Boskovic Institute, Bijenicka cesta 54, 10000 Zagreb (Croatia); Planinic, Pavica, E-mail: planinic@irb.h [Ruder Boskovic Institute, Bijenicka cesta 54, 10000 Zagreb (Croatia); Brnicevic, Nevenka [Ruder Boskovic Institute, Bijenicka cesta 54, 10000 Zagreb (Croatia); Giester, Gerald [Institut fuer Mineralogie und Kristallographie, Universitaet Wien-Geozentrum Althanstrasse, 14, 1090 Wien (Austria)

    2009-09-15T23:59:59.000Z

    A new hexanuclear cluster compound, [Et{sub 4}N][Ta{sub 6}Br{sub 12}(H{sub 2}O){sub 6}]Br{sub 4}.4H{sub 2}O (Et=ethyl) (1), with the paramagnetic [Ta{sub 6}Br{sub 12}]{sup 3+} cluster entity, was synthesized and characterized by elemental and TG/DTA analyses, IR and UV/Vis spectroscopy and by a single-crystal X-ray diffraction study. The presence of the paramagnetic [Ta{sub 6}Br{sub 12}]{sup 3+} unit was confirmed also by the room-temperature magnetic and EPR measurements. The compound crystallizes in the tetragonal I4{sub 1}/a space group, with a=14.299(5), c=21.241(5) A, Z=4, R{sub 1}(F)/wR{sub 2}(F{sup 2})=0.0296/0.0811. The structure contains discrete [Ta{sub 6}Br{sub 12}(H{sub 2}O){sub 6}]{sup 3+} cations with an octahedron of metal atoms edge-bridged by bromine atoms and with water molecules occupying all six terminal positions. The cluster units are positioned in the vertices of the three-dimensional (pseudo)diamond lattice. The structure shows similarities with literature reported structures of cluster compounds crystallizing in the diamond (Fd3-barm) space group. - Graphical abstract: Two interpenetrating (pseudo)diamond nets formed by packing of the paramagnetic [Ta{sub 6}Br{sub 12}(H{sub 2}O)]{sup 3+} (octahedral) and diamagnetic [Et{sub 4}N]{sup +} (spheres) cations.

  15. Studies of Nb3Sn Strands Based on the Restacked-Rod Process for High-Field Accelerator Magnets Nb3Sn

    SciTech Connect (OSTI)

    Barzi, E; Bossert, M; Gallo, G; Lombardo, V; Turrioni, D; Yamada, R; Zlobin, A V

    2012-06-01T23:59:59.000Z

    A major thrust in Fermilab's accelerator magnet R&D program is the development of Nb3Sn wires which meet target requirements for high field magnets, such as high critical current density, low effective filament size, and the capability to withstand the cabling process. The performance of a number of strands with 150/169 restack design produced by Oxford Superconducting Technology was studied for round and deformed wires. To optimize the maximum plastic strain, finite element modeling was also used as an aid in the design. Results of mechanical, transport and metallographic analyses are presented for round and deformed wires.

  16. Test Results of HD1b, an upgraded 16 Tesla Nb3Sn DipoleMagnet

    SciTech Connect (OSTI)

    Lietzke, A.F.; Bartlett, S.E.; Bish, P.; Caspi, S.; Dietderich,D.; Ferracin, P.; Gourlay, S.; Hafalia, A.R.; Hannaford, C.R.; Higley,H.; Lau, W.; Liggins, N.; Mattafirri, S.; Nyman, M.; Sabbi, G.; Scanlan,R.; Swanson, J.

    2005-04-16T23:59:59.000Z

    The Superconducting Magnet Group at Lawrence Berkeley National Laboratory has been developing high-field, brittle-superconductor, accelerator magnet technology, in which the conductor's support system can significantly impact conductor performance (as well as magnet training). A recent H-dipole coil test (HD1) achieved a peak bore-field of 16 Tesla, using two, flat-racetrack, double-layer Nb{sub 3}Sn coils. However, its 4.5 K training was slow, with an erratic plateau at {approx}92% of its un-degraded ''short-sample'' expectation ({approx}16.6 T). Quench-origins correlated with regions where low conductor pre-stress had been expected (3-D FEM predictions and variations in 300 K coil-size). The coils were re-assembled with minor coil-support changes and re-tested as ''HD1b'', with a 185 MPa average pre-stress (30 MPa higher than HD1, with a 15-20 MPa pole-turn margin expected at 17 T). Training started higher (15.1 T), and quickly reached a stable, negligibly higher plateau at 16 T. After a thermal cycle, training started at 15.4 T, but peaked at 15.8 T, on the third attempt, before degrading to a 15.7 T plateau. The temperature dependence of this plateau was explored in a sub-atmospheric LHe bath to 3.0 K. Magnet performance data for both thermal cycles is presented and discussed, along with issues for future high-field accelerator magnet development.

  17. mm-Wave Op-Amps employing simple-Miller compensation, with OIP3/PDC ratios of 211 (10 dB NF) and 144 (6.0 dB NF) at 2 GHz

    E-Print Network [OSTI]

    Rodwell, Mark J. W.

    mm-Wave Op-Amps employing simple-Miller compensation, with OIP3/PDC ratios of 211 (10 dB NF/PDC ratio at fs = 2-3 GHz, compared to state-of-the-art. We address considerations important 1000 mW power dissipation PDC . This very high ratio of output-referred third-order-intercept power

  18. Role of calcium in prolactin-stimulated c-myc gene expression and mitogenesis in Nb2 lymphoma cells

    SciTech Connect (OSTI)

    Murphy, P.R.; DiMattia, G.E.; Friesen, H.G.

    1988-06-01T23:59:59.000Z

    Receptor-activated transmembrane calcium flux has been implicated as a mediator of the actions of many growth factors and hormones. We examined the effects of PRL, calcium ionophores, and calcium antagonists on /sup 45/Ca2+ flux, c-myc gene expression, and DNA synthesis in the PRL-dependent rat Nb2 lymphoma cell line. PRL had no detectable effects on /sup 45/Ca2+ uptake or efflux, and the mitogenic effects of PRL could not be reproduced by the calcium ionophore A23187 alone or in combination with the tumor-promoting phorbol ester 12-O-tetra-decanoyl-phorbol-13 acetate (TPA). PRL, but not A23187 or TPA, stimulated c-myc gene expression in quiescent Nb2 cells. Exposure to PRL for brief periods (15 min to 4 h), followed by extensive washing, resulted in a time- and dose-dependent activation of DNA synthesis measured 16 h later. This activation was not blocked by addition of excess anti-PRL antiserum after the wash steps, indicating that the observed stimulation was not due to residual PRL. Despite the marked increase in DNA synthesis, removal of PRL after 4 h prevented mitosis, suggesting that PRL may be required throughout the cell cycle for Nb2 cell proliferation. Although continuous incubation with calcium antagonists resulted in a dose-dependent inhibition of PRL-stimulated DNA synthesis, activation of DNA synthesis by brief exposure to PRL was not inhibited by the presence of EGTA, calcium channel blockers (nifedipine, cobalt chloride), or calmodulin inhibitors (trifluoperazine, N-6-aminohexyl-5-chloronaphthalene sulfonamide). PRL-stimulated c-myc expression was attenuated, but not blocked, by the calcium channel antagonists. However, the putative intracellular calcium antagonist TMB-8 inhibited both c-myc expression and DNA synthesis in a dose-dependent manner (IC50 = 16 microM).

  19. Effects of Long-Term Service on The Aging Behavior of A Water-Quenched U{sub 6}Nb Alloy

    SciTech Connect (OSTI)

    Zhou, Jikou; Hsiung, Luke L. [Chemistry and Materials Science Directorate, Lawrence Livermore National Laboratory, Livermore, California (United States)

    2007-07-01T23:59:59.000Z

    Microhardness testing and transmission electron microscopy are used to study the effects of long-term service on the aging behavior of a water-quenched U{sub 6} wt.% Nb alloy when subjected to isothermal aging at 200 deg. C. The original {alpha}'' phase in the WQ-U{sub 6}Nb alloy is found to become partially ordered over 18 years of aging at ambient temperatures, i.e., natural aging, forming a microstructure that is featured by antiphase domain boundaries (APBs). When subsequently aged at 200 deg. C, an ordered phase U{sub 3}Nb is precipitated through a nucleation-and-growth mechanism, suppressing spinodal decomposition that occurs when the water-quenched alloy is artificially aged at the same temperature. The different phase transformation paths lead to different microhardness changes during artificial aging: the naturally aged alloy is more slowly hardened, but to a greater microhardness peak value. (authors)

  20. SciDB DBMS Research at M.I.T. Michael Stonebraker, Jennie Duggan, Leilani Battle, Olga Papaemmanouil

    E-Print Network [OSTI]

    SciDB DBMS Research at M.I.T. Michael Stonebraker, Jennie Duggan, Leilani Battle, Olga Papaemmanouil {stonebraker, jennie, leilani}@csail.mit.edu, olga@cs.brandeis.edu Abstract This paper presents, and the state of the software at the time of publication. In this paper, we consider a collection of research

  1. Electric field effects on spin accumulation in Nb-doped SrTiO{sub 3} using tunable spin injection contacts at room temperature

    SciTech Connect (OSTI)

    Kamerbeek, A. M.; Vries, E. K. de; Wees, B. J. van; Banerjee, T., E-mail: T.Banerjee@rug.nl [Physics of Nanodevices, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands); Dankert, A.; Dash, S. P. [Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Gothenburg (Sweden)

    2014-05-26T23:59:59.000Z

    We report on features in charge transport and spin injection in an oxide semiconductor, Nb-doped SrTiO{sub 3}. This is demonstrated using electrically tunable spin injection contacts which exploit the large electric field at the interface and its interplay with the relative permittivity of the semiconductor. We realize spin accumulation in Nb-doped SrTiO{sub 3} which displays a unique dependence of the spin lifetime with bias polarity. These findings suggest a strong influence of the interface electric field on the charge transport as well as on spin accumulation unlike in conventional semiconductors and opens up promising avenues in oxide spintronics.

  2. Progress in the long Nb3Sn quadrupole R&D by LARP

    SciTech Connect (OSTI)

    Ambrosio, G [Fermilab; Andreev, N [Brookhaven; Anerella, M [Fermilab; Barzi, E [LBL, Berkeley; Bocian, D [Fermilab; Bossert, R [LBL, Berkeley; Buehler, M [Fermilab; Caspi, S [Brookhaven; Chlachidze, G [Berkeley; Dietderich, D [Brookhaven; DiMarco, J [Fermilab

    2012-06-01T23:59:59.000Z

    After the successful test of the first long Nb3Sn quadrupole (LQS01) the US LHC Accelerator Research Program (LARP, a collaboration of BNL, FNAL, LBNL and SLAC) is assessing training memory, reproducibility, and other accelerator quality features of long Nb3Sn quadrupole magnets. LQS01b (a reassembly of LQS01 with more uniform and higher pre-stress) was subjected to a full thermal cycle and reached the previous plateau of 222 T/m at 4.5 K in two quenches. A new set of four coils, made of the same type of conductor used in LQS01 (RRP 54/61 by Oxford Superconducting Technology), was assembled in the LQS01 structure and tested at 4.5 K and lower temperatures. The new magnet (LQS02) reached the target gradient (200 T/m) only at 2.6 K and lower temperatures, at intermediate ramp rates. The preliminary test analysis, here reported, showed a higher instability in the limiting coil than in the other coils of LQS01 and LQS02.

  3. Assembly and Test of HD2, a 36 mm bore high field Nb3Sn Dipole Magnet

    SciTech Connect (OSTI)

    Ferracin, P.; Bingham, B.; Caspi, S.; Cheng, D. W,.; Dietderich, D. R.; Felice, H.; Godeke, A.; Hafalia, A. R.; Hannaford, C. R.; Joseph, J.; Lietzke, A. F.; Lizarazo, J.; Sabbi, G.; Trillaud, F.; Wang, X.

    2008-08-17T23:59:59.000Z

    We report on the fabrication, assembly, and test of the Nb{sub 3}Sn dipole magnet HD2. The magnet, aimed at demonstrating the application of Nb{sub 3}Sn superconductor in high field accelerator-type dipoles, features a 36 mm clear bore surrounded by block-type coils with tilted ends. The coil design is optimized to minimize geometric harmonics in the aperture and the magnetic peak field on the conductor in the coil ends. The target bore field of 15 T at 4.3 K is consistent with critical current measurements of extracted strands. The coils are horizontally pre-stressed during assembly using an external aluminum shell pre-tensioned with water-pressurized bladders. Axial pre-loading of the coil ends is accomplished through two end plates and four aluminum tension rods. The strain in coil, shell, and rods is monitored with strain gauges during assembly, cool-down and magnet excitation, and compared with 3D finite element computations. Magnet's training performance, quench locations, and ramp-rate dependence are then analyzed and discussed.

  4. Mechanical Design of HD2, a 15 T Nb3Sn Dipole Magnet with a 35 mm Bore

    SciTech Connect (OSTI)

    Ferracin, P.; Bartlett, S.E.; Caspi, S.; Dietderich, D.R.; Gourlay, S.A.; Hafalia, A.R.; Hannaford, C.R.; Lietzke, A.F.; Mattafirri, S.; McInturff, A.D.; Sabbi, G.L.

    2006-06-01T23:59:59.000Z

    After the fabrication and test of HD1, a 16 T Nb{sub 3}Sn dipole magnet based on flat racetrack coil configuration, the Superconducting Magnet Program at Lawrence Berkeley National Laboratory (LBNL) is developing the Nb{sub 3}Sn dipole HD2. With a dipole field above 15 T, a 35 mm clear bore, and nominal field harmonics within a fraction of one unit, HD2 represents a further step towards the application of block-type coils to high-field accelerator magnets. The design features tilted racetrack-type ends, to avoid obstructing the beam path, and a 4 mm thick stainless steel tube, to support the coil during the preloading operation. The mechanical structure, similar to the one used for HD1, is based on an external aluminum shell pretensioned with pressurized bladders. Axial rods and stainless steel plates provide longitudinal support to the coil ends during magnet excitation. A 3D finite element analysis has been performed to evaluate stresses and deformations from assembly to excitation, with particular emphasis on conductor displacements due to Lorentz forces. Numerical results are presented and discussed.

  5. Final Development and test preparation of the first 3.7m long Nb3Sn quadrupole by LARP

    SciTech Connect (OSTI)

    Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bingham, B.; Bocian, D.; Bordini, B.; Bossert, R.; Bottura, L.; Caspi, S.; Chlachidize, G.; /Fermilab /Brookhaven /LBL, Berkeley /CERN

    2009-10-01T23:59:59.000Z

    The test of the first LARP (LHC Accelerator Research Program) Long Quadrupole is a significant milestone toward the development of Nb{sub 3}Sn quadrupoles for LHC (Large Hadron Collider) Luminosity Upgrades. These 3.7-m long magnets, scaled from the 1-m long Technological Quadrupoles, are used to develop our capabilities to fabricate and assemble Nb{sub 3}Sn coils and structures with lengths comparable to accelerator magnet dimensions. The long quadruples have a target gradient of 200 T/m in a 90-mm aperture. Pre-stress and support are provided by an Al-shell-based structure pre-loaded using bladders and keys. The coils were fabricated at BNL and FNAL, the shell-based structure was designed and assembled at LBNL, the test is performed at FNAL. In this paper we present the final steps of the development of the first model (LQS01), several upgrades to the test facility, the test results of witness cables, and the short sample limit.

  6. Laboratory Problems TA Orientation

    E-Print Network [OSTI]

    Minnesota, University of

    the ball's kinetic energy at all times during its fall to its velocity. Relate the kinetic energy of a ball this relationship and calculus to write an expression for the ball's velocity as a function of time. Use

  7. Advanced NTR options. [Ta

    SciTech Connect (OSTI)

    Davis, J.W.; Mills, J.C.; Glass, J.F.; Tu, W. (Rockwell International/Rocketdyne Division, 6633 Canoga Avenue, MS HB23 Canoga Park, California 81303 (US))

    1991-01-05T23:59:59.000Z

    Advanced NTR concepts which offer performance improvements over the ROVER/NERVA designs have been investigated. In addition, the deliverable performance of low pressure operation and materials issues have been investigated. Based on current experience, a maximum exit gas temperature of 3200 K is likely achievable with a ZrC based PBR design. At 3200 K a low pressure NTR would have marginal performance advantage (Isp) over a high pressure system. If tantalum or other high melting point carbides are used then an exit gas temperature of 3500 K may be feasible. At 3500 K low pressure operation offers more significant performance improvements which could outweigh associated size and mass penalties.

  8. Today's Agenda TA Information

    E-Print Network [OSTI]

    Lei, Jeff Yu

    the naive-ticket-machine project. ­ Machines supply tickets of a fixed price. ­ Methods insertMoney, get of an object. public class TicketMachine { private int price; private int balance; private int total; Further details omitted. } private int price; visibility modifier type variable name #12;5 9CSE 1325: Object

  9. Data:00e1ac01-203d-48bd-9db5-a44ef5f26deb | Open Energy Information

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    db5-a44ef5f26deb No revision has been approved for this page. It is currently under review by our subject matter experts. Jump to: navigation, search Loading... 1. Basic...

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  17. Collapse of ferromagnetism in itinerant-electron system: A magnetic, transport properties, and high pressure study of (Hf,Ta)Fe{sub 2} compounds

    SciTech Connect (OSTI)

    Diop, L. V. B., E-mail: leopold.diop@neel.cnrs.fr; Isnard, O. [Univ. Grenoble Alpes, Inst NEEL, F-38042 Grenoble (France); CNRS, Inst NEEL, F-38042 Grenoble (France); Kastil, J. [Univ. Grenoble Alpes, Inst NEEL, F-38042 Grenoble (France); CNRS, Inst NEEL, F-38042 Grenoble (France); Institute of Physics AS CR v.v.i., Na Slovance 2, 182 21 Prague 8 (Czech Republic); Arnold, Z.; Kamarad, J. [Institute of Physics AS CR v.v.i., Na Slovance 2, 182 21 Prague 8 (Czech Republic)

    2014-10-28T23:59:59.000Z

    The magnetism and transport properties were studied for Laves (Hf,Ta)Fe{sub 2} itinerant-electron compounds, which exhibit a temperature-induced first-order transition from the ferromagnetic (FM) to the antiferromagnetic (AFM) state upon heating. At finite temperatures, the field-induced metamagnetic phase transition between the AFM and FM has considerable effects on the transport properties of these model metamagnetic compounds. A large negative magnetoresistance of about 14% is observed in accordance with the metamagnetic transition. The magnetic phase diagram is determined for the Laves Hf{sub 1?x}Ta{sub x}Fe{sub 2} series and its Ta concentration dependence discussed. An unusual behavior is revealed in the paramagnetic state of intermediate compositions, it gives rise to the rapid increase and saturation of the local spin fluctuations of the 3d electrons. This new result is analysed in the frame of the theory of Moriya. For a chosen composition Hf{sub 0.825}Ta{sub 0.175}Fe{sub 2}, exhibiting such remarkable features, a detailed investigation is carried out under hydrostatic pressure up to 1?GPa in order to investigate the volume effect on the magnetic properties. With increasing pressure, the magnetic transition temperature T{sub FM-AFM} from ferromagnetic to antiferromagnetic order decreases strongly non-linearly and disappears at a critical pressure of 0.75?GPa. In the pressure-induced AFM state, the field-induced first-order AFM-FM transition appears and the complex temperature dependence of the AFM-FM transition field is explained by the contribution from both the magnetic and elastic energies caused by the significant temperature variation of the amplitude of the local Fe magnetic moment. The application of an external pressure leads also to the progressive decrease of the Néel temperature T{sub N}. In addition, a large pressure effect on the spontaneous magnetization M{sub S} for pressures below 0.45?GPa, dln(M{sub s})/dP?=??6.3?×?10{sup ?2?}GPa{sup ?1} was discovered. The presented results are consistent with Moriya's theoretical predictions and can significantly help to better understand the underlying physics of itinerant electron magnetic systems nowadays widely investigated for both fundamental and applications purposes.

  18. Electronic Instability in a Zero-Gap Semiconductor: The Charge-Density Wave in (TaSe4)2I

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tournier-Colletta, C.; Moreschini, L.; Autčs, G.; Moser, S.; Crepaldi, A.; Berger, H.; Walter, A. L.; Kim, K. S.; Bostwick, A.; Monceau, P.; Rotenberg, E.; Yazyev, O. V.; Grioni, M.

    2013-06-01T23:59:59.000Z

    We report a comprehensive study of the paradigmatic quasi-1D compound (TaSe4)2I performed by means of angle-resolved photoemission spectroscopy (ARPES) and first-principles electronic structure calculations. We find it to be a zero-gap semiconductor in the nondistorted structure, with non-negligible interchain coupling. Theory and experiment support a Peierls-like scenario for the charge-density wave formation below TCDW=263??K, where the incommensurability is a direct consequence of the finite interchain coupling. The formation of small polarons, strongly suggested by the ARPES data, explains the puzzling semiconductor-to-semiconductor transition observed in transport at TCDW.

  19. Role of the Vortex-Core Energy on the Berezinskii-Kosterlitz-Thouless Transition in Thin Films of NbN

    E-Print Network [OSTI]

    Raychaudhuri, Pratap

    Role of the Vortex-Core Energy on the Berezinskii-Kosterlitz-Thouless Transition in Thin Films-Kosterlitz-Thouless (BKT) transition in thin films of NbN at various film thickness, by probing the effect of vortex played by the vortex-core energy in determining the characteristic signatures of the BKT physics, and we

  20. Effect of discharge current and deposition temperature on roughness and density of NbC films fabricated by ion beam sputtering technique

    SciTech Connect (OSTI)

    Dhawan, Rajnish, E-mail: rajnish@rrcat.gov.in; Rai, Sanjay, E-mail: rajnish@rrcat.gov.in; Lodha, G. S., E-mail: rajnish@rrcat.gov.in [X-ray optics Section, Indus Synchrotron Utilization Division, Raja Ramanna Center for Advanced Technology, Indore-452013 (India)

    2014-04-24T23:59:59.000Z

    NbC films were prepared using Ion beam sputtering system at various discharges current from 0.4 amps to 1.2 amps at room temperature. Effect of temperature on NbC films were also studied by depositing NbC films at various temperatures from room temperature to 200,300,400 and 600°C. X-ray reflectivity (XRR) study shows that surface roughness of the film decreases with decrease in discharge current. The optimum lowest roughness 3.2Ĺ having density 92% of bulk was achieved at discharge current 0.6 amps at 3.0 cm{sup 3}/min Ar gas flow. X-ray study also shows that film roughness decreases with increase in temperature of the film and after a certain temperature it increases with increase in temperature. The lowest surface roughness 2.1Ĺ was achieved at 300°C with density 83% of bulk NbC at constant discharge current 0.6 amps.

  1. n-lnAs/GaAs heterostructure superconducting weak Hnks with Nb A. W. Kleinsasser, T. N. Jackson, G. D. Pettit, H. Schmid, J. M. Woodall, and

    E-Print Network [OSTI]

    Woodall, Jerry M.

    1986) We report on the fabrication and characterization of planar superconductor-normal- superconductor-effect transistors (FETs), 1-4 which were first proposed a number of years ago.5 - 7 These are superconductor-normal-superconductorn-lnAs/GaAs heterostructure superconducting weak Hnks with Nb electrodes A. W. Kleinsasser, T. N

  2. Dielectric and photovoltaic phenomena in tungsten-doped Pb,,Mg1/3Nb2/3...1-xTixO3 crystal

    E-Print Network [OSTI]

    Dielectric and photovoltaic phenomena in tungsten-doped Pb,,Mg1/3Nb2/3...1-xTixO3 crystal Chi. The tungsten-doped Pb1-xLax ZryTiz 1-x/4O3 ceramics, i.e., PLZT x/y/z , exhibits a large photovoltaic ef- fect

  3. Superconductlng InGaAs junction field...effect transistors with Nb electrodes A. W. Kleinsasser, T. N. Jackson, D. Mcinturff, F. Rammo, G. D. Pettit,

    E-Print Network [OSTI]

    Woodall, Jerry M.

    is set by the normal coherence length ofthe semiconductor, and (2) the superconductor-semicon- ductorSuperconductlng InGaAs junction field...effect transistors with Nb electrodes A. W. Kleinsasser, T for publication 21 August 1989) We describe the design, fabrication, and characterization of superconducting 1n0

  4. Perovskite-type SrTi{sub 1-x}Nb{sub x}(O,N){sub 3} compounds: Synthesis, crystal structure and optical properties

    SciTech Connect (OSTI)

    Maegli, Alexandra, E-mail: Alexandra.Maegli@empa.c [Empa - Swiss Federal Laboratories for Materials Science and Technology, Solid State Chemistry and Catalysis, Ueberlandstr. 129, CH-8600 Duebendorf (Switzerland); Yoon, Songhak, E-mail: Songhak.Yoon@empa.c [Empa - Swiss Federal Laboratories for Materials Science and Technology, Solid State Chemistry and Catalysis, Ueberlandstr. 129, CH-8600 Duebendorf (Switzerland); Otal, Eugenio, E-mail: Eugenio.Otal@empa.c [Empa - Swiss Federal Laboratories for Materials Science and Technology, Solid State Chemistry and Catalysis, Ueberlandstr. 129, CH-8600 Duebendorf (Switzerland); Karvonen, Lassi, E-mail: Lassi.Karvonen@empa.c [Empa - Swiss Federal Laboratories for Materials Science and Technology, Solid State Chemistry and Catalysis, Ueberlandstr. 129, CH-8600 Duebendorf (Switzerland); Mandaliev, Peter, E-mail: Petar.Mandaliev@env.ethz.c [Empa - Swiss Federal Laboratories for Materials Science and Technology, Solid State Chemistry and Catalysis, Ueberlandstr. 129, CH-8600 Duebendorf (Switzerland); Weidenkaff, Anke, E-mail: Anke.Weidenkaff@empa.c [Empa - Swiss Federal Laboratories for Materials Science and Technology, Solid State Chemistry and Catalysis, Ueberlandstr. 129, CH-8600 Duebendorf (Switzerland)

    2011-04-15T23:59:59.000Z

    The synthesis, crystal structure, thermal stability and absorbance spectra of perovskite-type oxynitrides with the general formula SrTi{sub 1-x}Nb{sub x}(O,N){sub 3} (x=0.05, 0.10, 0.20, 0.50, 0.80, 0.90, 0.95) have been investigated. Oxide samples were prepared by a polymerized complex synthesis route and post-treated under ammonia at 850 {sup o}C for 24 h to substitute nitrogen for oxygen. Synchrotron X-ray powder diffraction (XRD) evidenced that the mixed oxide phases were all transformed into oxynitrides with perovskite-type structure during a thermal ammonolysis. SrTi{sub 1-x}Nb{sub x}(O,N){sub 3} with compositions x{<=}0.80 crystallized in a cubic and samples with x{>=}0.90 in a tetragonal structure. The Rietveld refinement indicated a continuous enlargement of the lattice parameters towards higher niobium content of the samples. Thermogravimetric analysis (TGA) and hotgas extraction revealed the dependence of the nitrogen incorporation upon the degree of niobium substitution. It showed that more nitrogen was detected in the samples with higher niobium content. Furthermore, TGA disclosed stability for all oxynitrides at T{<=}400 {sup o}C. Diffuse reflectance spectroscopy indicated a continuous decrease of the band gap's width from 3.24 eV (SrTi{sub 0.95}Nb{sub 0.05} (O,N){sub 3}) to 1.82 eV (SrTi{sub 0.05}Nb{sub 0.95}(O,N){sub 3}) caused by the increasing amount of nitrogen towards the latter composition. -- Graphical Abstract: The system SrTi{sub 1-x}Nb{sub x}(O,N){sub 3} is described and the changes in crystal structure, nitrogen content and width of the band gap are discussed. Display Omitted Research highlights: {yields} Synthesis of SrTi{sub 1-x}Nb{sub x}(O,N){sub 3} perovskite-type oxynitrides via thermal ammonolysis. {yields} Co-substitution of Nb{sup 5+} enabled to adjust the amount nitrogen insertion. {yields} Tuning of the optical band gap through nitrogen.{yields} Changes of crystal structure from cubic to tetragonal with increasing niobium content.

  5. Novel chemically stable Ba3Ca1.18Nb1.82-xYxO9- proton conductor: improved proton conductivity through tailored cation ordering

    SciTech Connect (OSTI)

    Wang, Siwei [University of South Carolina, Columbia] [University of South Carolina, Columbia; Chen, Yan [ORNL] [ORNL; Fang, Shumin [University of South Carolina, Columbia] [University of South Carolina, Columbia; Zhang, Lingling [University of South Carolina, Columbia] [University of South Carolina, Columbia; Tang, Ming [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); An, Ke [ORNL] [ORNL; Brinkman, Dr. Kyle S. [Savannah River National Laboratory (SRNL), Aiken, S.C.] [Savannah River National Laboratory (SRNL), Aiken, S.C.; Chen, Fanglin [University of South Carolina, Columbia] [University of South Carolina, Columbia

    2014-01-01T23:59:59.000Z

    Simple perovskite-structured proton conductors encounter significant challenges to simultaneously achieving excellent chemical stability and proton conductivity that are desirable for many important applications in energy conversion and storage. This work demonstrates that Y-doped complex-perovskite-structured Ba3Ca1.18Nb1.82 xYxO9 materials possess both improved proton conductivity and exceptional chemical stability. Neutron powder diffraction refinement revealed a Fm3 m perovskite-structure and increased oxygen vacancy concentration due to the Y doping. High-resolution TEM analysis confirmed the perturbation of the B site cation ordering in the structure for the Ba3Ca1.18Nb1.82 xYxO9 materials. Such combined effects led to improved proton conductivity with a value of 5.3 10 3 S cm 1 at 600 C for Ba3Ca1.18Nb1.52Y0.3O9 (BCNY0.3), a value 2.4 times higher compared with that of the undoped Ba3Ca1.18Nb1.82O9 . The Ba3Ca1.18Nb1.82 xYxO9 materials showed remarkable chemical stability toward water and demonstrated no observable reactions to CO2 exposure. Ionic transport number studies showed that BCNY0.3 had predominantly proton conduction below 600 C. Solid oxide fuel cells using BCNY0.3 as an electrolyte demonstrated cell power output of 103 mW cm 2 at 750 C. These results suggest that a doping strategy that tailors the cation ordering in complex perovskites provides a new direction in the search for novel proton conducting ceramics.

  6. HUMAN MACHINE INTERFACE (HMI) EVALUATION OF ROOMS TA-50-1-60/60A AT THE RADIOACTIVE LIQUID WASTE TREATMENT FACILITY (RLWTF)

    SciTech Connect (OSTI)

    Gilmore, Walter E. [Los Alamos National Laboratory; Stender, Kerith K. [Los Alamos National Laboratory

    2012-08-29T23:59:59.000Z

    This effort addressed an evaluation of human machine interfaces (HMIs) in Room TA-50-1-60/60A of the Radioactive Liquid Waste Treatment Facility (RLWTF). The evaluation was performed in accordance with guidance outlined in DOE-STD-3009, DOE Standard Preparation Guide for U.S. Department of Energy Nonreactor Nuclear Facility Documented Safety Analyses, 2006 [DOE 2006]. Specifically, Chapter 13 of DOE 2006 highlights the 10 CFR 830, Nuclear Safety Management, 2012, [CFR 2012] and DOE G 421.1-2 [DOE 2001a] requirements as they relate to the human factors process and, in this case, the safety of the RLWTF. The RLWTF is a Hazard Category 3 facility and, consequently, does not have safety-class (SSCs). However, safety-significant SSCs are identified. The transuranic (TRU) wastewater tanks and associated piping are the only safety-significant SSCs in Rooms TA-50-1-60/60A [LANL 2010]. Hence, the human factors evaluation described herein is only applicable to this particular assemblage of tanks and piping.

  7. An aqueous route to [Ta6O19]8- and solid-state studies of isostructural niobium and tantalum oxide complexes.

    SciTech Connect (OSTI)

    Nyman, May D.; Anderson, Travis Mark [Sandia National Laboratories, Albuquerque, NM; Alam, Todd M. [Sandia National Laboratories, Albuquerque, NM; Rodriguez, Mark Andrew [Sandia National Laboratories, Albuquerque, NM; Joel N. Bixler; Francois Bonhomme

    2007-10-01T23:59:59.000Z

    Tantalate materials play a vital role in our high technology society: tantalum capacitors are found in virtually every cell phone. Furthermore, electronic characteristics and the incredibly inert nature of tantalates renders them ideal for applications such as biomedical implants, nuclear waste forms, ferroelectrics, piezoelectrics, photocatalysts and optical coatings. The inert and insoluble nature of tantalates is not fundamentally understood; and furthermore poor solubility renders fabrication of novel or optimized tantalates very difficult. We have developed a soft chemical route to water-soluble tantalum oxide clusters that can serve as both precursors for novel tantalate materials and ideal models for experimental and computational approaches to understanding the unusually inert behavior of tantalates. The water soluble cluster, [Ta6O19]8- is small, highly symmetric, and contains the representative oxygen types of a metal oxide surface, and thus ideally mimics a complex tantalate surface in a simplistic form that can be studied unambiguously. Furthermore; in aqueous solution, these highly charged and super-basic clusters orchestrate surprising acid-base behavior that most likely plays an important role in the inertness of related oxide surfaces. Our unique synthetic approach to the [Ta6O19]8- cluster allowed for unprecedented enrichment with isotopic labels (17O), enabling detailed kinetic and mechanistic studies of the behavior of cluster oxygens, as well as their acid-base behavior. This SAND report is a collection of two publications that resulted from these efforts.

  8. Joint contributions of Ag ions and oxygen vacancies to conducting filament evolution of Ag/TaO{sub x}/Pt memory device

    SciTech Connect (OSTI)

    Chung, Yu-Lung; Cheng, Wen-Hui; Chen, Wei-Chih; Jhan, Sheng-An; Chen, Jen-Sue, E-mail: jenschen@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Jeng, Jiann-Shing [Department of Materials Science, National University of Tainan, Tainan 700, Taiwan (China)

    2014-10-28T23:59:59.000Z

    The electroforming and resistive switching behaviors in the Ag/TaO{sub x}/Pt trilayer structure are investigated under a continual change of temperatures between 300?K and 100?K to distinguish the contributions of Ag ions and oxygen vacancies in developing of conducting filaments. For either electroforming or resistive switching, a significantly higher forming/set voltages is needed as the device is operated at 100?K, as compared to that observed when operating at 300?K. The disparity in forming/set voltages of Ag/TaO{sub x}/Pt operating at 300?K and 100?K is attributed to the contribution of oxygen vacancies, in addition to Ag atoms, in formation of conducting filament at 100?K since the mobilities of oxygen vacancies and Ag ions become comparable at low temperature. The presence of oxygen vacancy segment in the conducting filament also modifies the reset current from a gradually descending behavior (at 300?K) to a sharp drop (at 100?K). Furthermore, the characteristic set voltage and reset current are irreversible as the operation temperature is brought from 100?K back to 300?K, indicating the critical role of filament constituents on the switching behaviors of Ag/oxide/Pt system.

  9. Manufacturing and performance of ceramic/metal matrix composite electrical discharge machining electrodes

    E-Print Network [OSTI]

    Kim, Eugene Ty

    1998-01-01T23:59:59.000Z

    The manufacturing and performance of ceramic/metal matrix composite (cermet) electrical discharge machining (EDM) electrodes have been investigated. The processing techniques necessary for creating TiB2/Cu, TaC/Cu, TaC/Cu(s), TaC/CuNi, TaC/Al, Nb...

  10. Manufacturing and performance of ceramic/metal matrix composite electrical discharge machining electrodes 

    E-Print Network [OSTI]

    Kim, Eugene Ty

    1998-01-01T23:59:59.000Z

    The manufacturing and performance of ceramic/metal matrix composite (cermet) electrical discharge machining (EDM) electrodes have been investigated. The processing techniques necessary for creating TiB2/Cu, TaC/Cu, TaC/Cu(s), TaC/CuNi, TaC/Al, Nb...

  11. Optimization and test of a 120mm LARP Nb3Sn quadrupole coil using magnetic mirror structure

    SciTech Connect (OSTI)

    Bossert, R.; Ambrosio, G.; Andreev, N.; /Fermilab; Anerella, M.; /Brookhaven; Barzi, E.; /Fermilab; Caspi, S.; /LBL, Berkeley; Cheng, D.; Chlachidze, G.; /Fermilab; Dietderich, D.; Felice, H.; Ferracin, P.; /LBL, Berkeley /Brookhaven /LBL, Berkeley /Fermilab /LBL, Berkeley /Brookhaven

    2011-09-01T23:59:59.000Z

    The US-LARP collaboration is developing a new generation of large-aperture high-field quadrupoles based on Nb{sub 3}Sn superconductor for the LHC upgrades. The development and implementation of this new technology involves the fabrication and testing of series of model magnets, coils and other components with various design and processing features. New 120-mm HQ coils made of Rutherford cable, one with an interlayer resistive core, and both with optimized reaction processes, were fabricated and tested using a quadrupole mirror structure under operating conditions similar to those in a real magnet. The coils were instrumented with voltage taps and strain gauges to study the mechanical and quench performance. Quench antenna and temperature gauges were installed in the mirror structure to measure the coil temperature and locate quench origins. This paper presents details of the coil design and fabrication procedures, coil assembly and pre-stress in the quadrupole mirror structure, and coil test results.

  12. ASSEMBLY AND TEST OF A 120 MM BORE 15 T NB3SN QUADRUPOLE FOR THE LHC UPGRADE

    SciTech Connect (OSTI)

    Felice, H.; Caspi, S.; Cheng, D.; Dietderich, D.; Ferracin, P.; Hafalia, R.; Joseph, J.; Lizarazo, J.; Sabbi, G. L.; Wang, X.; Anerella, M.; Ghosh, A. K.; Schmalzle, J.; Wanderer, P.; Ambrosio, G.; Bossert, R.; Zlobin, A. V.

    2010-05-23T23:59:59.000Z

    In support of the Large Hadron Collider (LHC) luminosity upgrade, the US LHC Accelerator Research Program (LARP) has been developing a 1-meter long, 120 mm bore Nb{sub 3}Sn IR quadrupole magnet (HQ). With a design short sample gradient of 219 T/m at 1.9 K and a peak field approaching 15 T, one of the main challenges of this magnet is to provide appropriate mechanical support to the coils. Compared to the previous LARP Technology Quadrupole and Long Quadrupole magnets, the purpose of HQ is also to demonstrate accelerator quality features such as alignment and cooling. So far, 8 HQ coils have been fabricated and 4 of them have been assembled and tested in HQ01a. This paper presents the mechanical assembly and test results of HQ01a.

  13. Design and Fabrication of a Supporting Structure for 3.6m Long Nb3Sn Racetrack Coils

    SciTech Connect (OSTI)

    Ambrosio, G.; Anerella, M.; Barzi, E.; Caspi, Shlomo; Cheng, Daniel; Dietderich, Daniel; Gourlay, Steve; Hafalia, A. Ray; Hannaford, Charles; Lietzke, Alan; Nobrega, A.R.; Sabbi, GianLuca; Schmalzle, J.; Wanderer, R. J; Zlobin, A.V.; Ferracin, P.

    2007-06-01T23:59:59.000Z

    As part of the LHC Accelerator Research Program (LARP), three US national laboratories (BNL, FNAL, and LBNL) are currently engaged in the development of superconducting magnets for the LHC Interaction Regions (IR) beyond the current design. As a first step towards the development of long Nb{sub 3}Sn quadrupole magnets, a 3.6 m long structure, based on the LBNL Subscale Common-Coil Magnet design, will be fabricated, assembled, and tested with aluminum-plate 'dummy coils'. The structure features an aluminum shell pre-tensioned over iron yokes using pressurized bladders and locking keys (bladder and key technology). Pre-load homogeneity and mechanical responses are monitored with pressure sensitive films and strain gauges mounted on the aluminum shell and the dummy coils. The details of the design and fabrication are presented and discussed, and the expected mechanical behavior is analyzed with finite element models.

  14. Test Results of HD2, A High Field Nb3Sn Dipole with A 36 MM Bore

    SciTech Connect (OSTI)

    Ferracin, Paolo

    2008-05-19T23:59:59.000Z

    The Superconducting Magnet Program at Lawrence Berkeley National Laboratory (LBNL) has developed the 1 m long Nb{sub 3}Sn dipole magnet HD2. With tilted (flared) ends to avoid obstructing a 36 mm clear bore, HD2 represents a step towards the use of block-type coils in high-field accelerator magnets. The coil design has been optimized to minimize geometric harmonics and reduce the conductor peak field in the end region, resulting in an expected short sample dipole field of 15 T. The support structure is composed by an external aluminum shell pre-tensioned with pressurized bladders and interference keys, and by two stainless steel end plates compressing the coil ends through four aluminum axial rods. We report on magnet design, assembly, and test results, including training performance, quench locations, and strain gauge measurements.

  15. Foundations for quantitative microstructural models to track evolution of the metallurgical state during high purity Nb cavity fabrication

    SciTech Connect (OSTI)

    Bieler, Thomas R [Michigan State University; Wright, Neil T [Michigan State University; Compton, Chris C [Facility for Rare Isotope Beams

    2014-03-15T23:59:59.000Z

    The goal of the Materials Science SRF Cavity Group of Michigan State University and the National Superconducting Cyclotron has been (and continues to be) to understand quantitatively the effects of process history on functional properties. These relationships were assessed via studies on Nb samples and cavity parts, which had various combinations of forming processes, welding, heat treatments, and surface preparation. A primary focus was on large-grain cavity building strategies. Effects of processing operations and exposure to hydrogen on the thermal conductivity has been identified in single and bi-crystal samples, showing that the thermal conductivity can be altered by a factor of 5 depending on process history. Characterization of single crystal tensile samples show a strong effect of crystal orientation on deformation resistance and shape changes. Large grain half cells were examined to characterize defect content and surface damage effects, which provided quantitative information about the depth damage layers from forming.

  16. Role of oxygen vacancies in resistive switching in Pt/Nb-doped SrTiO{sub 3}

    SciTech Connect (OSTI)

    Park, Jinho; Kwon, Deok-Hwang; Park, Hongwoo; Kim, M., E-mail: mkim@snu.ac.kr [Research Institute of Advanced Materials, Department of Material Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Jung, C. U. [Department of Physics, Hankuk University of Foreign Studies, Yongin, Kyungki 449-791 (Korea, Republic of)

    2014-11-03T23:59:59.000Z

    Oxygen vacancies at the metal/oxide interface, driven by an electric field, have been considered responsible for the switching to the low-resistance state. We studied the electrical properties, along with microscopic observations, of the Pt/Nb-doped SrTiO{sub 3} (001) single-crystal system. Electron energy loss spectroscopy revealed highly accumulated oxygen vacancies at the interface in the high-resistance state, contrasting to common explanation. Higher resistance state by more oxygen vacancies was further confirmed in Pt/H{sub 2}-annealed SrTiO{sub 3}. These results suggest the presence of an interfacial state which dominantly determined the resistivity by changing the barrier height at the interface.

  17. Spectroscopic Analysis of the DAB White Dwarf PG 1115+166: An Unresolved DA + DB Degenerate Binary

    E-Print Network [OSTI]

    P. Bergeron; James Liebert

    2001-10-25T23:59:59.000Z

    A spectroscopic analysis of the DAB white dwarf PG 1115+166 is presented. The observed hydrogen and helium line profiles are shown to be incompatible with model spectra calculated under the assumption of homogeneous or stratified chemical compositions. In contrast, an excellent fit to the optical spectrum of PG 1115+166 can be achieved if the object is interpreted as an unresolved double degenerate composed of a hydrogen-line DA star and a helium-line DB star. The atmospheric parameters obtained from the best fit are Teff=22,090 K and log g=8.12 for the DA star, Teff=16,210 K and log g=8.19 for the DB star. This binary interpretation is consistent with the results recently reported by Burleigh et al. that PG 1115+166 also exhibits radial velocity variations. The implications of this discovery with respect to the DAB spectral class are discussed.

  18. Infrared detection with high-{Tc} bolometers and response of Nb tunnel junctions to picosecond voltage pulses

    SciTech Connect (OSTI)

    Verghese, S.

    1993-05-01T23:59:59.000Z

    Oxide superconductors with high critical temperature {Tc} make sensitive thermometers for several types of infrared bolometers. The authors built composite bolometers with YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thermometers on sapphire substrates which have higher sensitivity than competing thermal detectors which operate at temperatures above 77 K. A 1 x 1 mm bolometer with gold black serving as the radiation absorber has useful sensitivity for wavelengths 20--100 {mu}m. A 3 x 3 mm bolometer with a bismuth film as the absorber operates from 20--100 {mu}m. High-{Tc} bolometers which are fabricated with micromachining techniques on membranes of Si or Si{sub 3}N{sub 4} have potential application to large-format arrays which are used for infrared imaging. A nonisothermal high-{Tc} bolometer can be fabricated on a membrane of yttria-stabilized zirconia (YSZ) which is in thermal contact with the heat sink along the perimeter of the membrane. A thermal analysis indicates that the YSZ membrane bolometer can have improved sensitivity compared to the sapphire bolometer for spectrometer applications. The quasiparticle tunneling current in a superconductor-insulator-superconductor (SIS) junction is highly nonlinear in the applied voltage. The authors have made the first measurement of the linear response of the quasiparticle current in a Nb/AlO{sub x}/Nb junction over a broad bandwidth from 75--200 GHz. Nonlinear measurements made with these pulses may provide information about the quasiparticle lifetime. Preliminary data from such measurements are presented.

  19. Electronic, structural and magnetic studies of niobium borides of group 8 transition metals, Nb{sub 2}MB{sub 2} (M=Fe, Ru, Os) from first principles calculations

    SciTech Connect (OSTI)

    Touzani, Rachid St.; Fokwa, Boniface P.T., E-mail: Boniface.Fokwa@ac.rwth-aachen.de

    2014-03-15T23:59:59.000Z

    The Nb{sub 2}FeB{sub 2} phase (U{sub 3}Si{sub 2}-type, space group P4/mbm, no. 127) is known for almost 50 years, but until now its magnetic properties have not been investigated. While the synthesis of Nb{sub 2}OsB{sub 2} (space group P4/mnc, no. 128, a twofold superstructure of U{sub 3}Si{sub 2}-type) with distorted Nb-layers and Os{sub 2}-dumbbells was recently achieved, “Nb{sub 2}RuB{sub 2}” is still not synthesized and its crystal structure is yet to be revealed. Our first principles density functional theory (DFT) calculations have confirmed not only the experimental structures of Nb{sub 2}FeB{sub 2} and Nb{sub 2}OsB{sub 2}, but also predict “Nb{sub 2}RuB{sub 2}” to crystalize with the Nb{sub 2}OsB{sub 2} structure type. According to chemical bonding analysis, the homoatomic B–B interactions are optimized and very strong, but relatively strong heteroatomic M–B, B–Nb and M–Nb bonds (M=Fe, Ru, Os) are also found. These interactions, which together build a three-dimensional network, are mainly responsible for the structural stability of these ternary borides. The density-of-states at the Fermi level predicts metallic behavior, as expected, from metal-rich borides. Analysis of possible magnetic structures concluded preferred antiferromagnetic ordering for Nb{sub 2}FeB{sub 2}, originating from ferromagnetic interactions within iron chains and antiferromagnetic exchange interactions between them. -- Graphical abstract: Nb{sub 2}FeB{sub 2} (U{sub 3}Si{sub 2} structure type, space group P4/mbm, no. 127) is predicted to order antiferromagnetically, due to the presence of iron chains which show ferromagnetic interactions in the chains and antiferromagnetic interactions between them. “Nb{sub 2}RuB{sub 2}” is predicted to crystallize with the recently discovered Nb{sub 2}OsB{sub 2} twofold superstructure (space group P4/mnc, no. 128) of U{sub 3}Si{sub 2} structure type. The building of ruthenium dumbbells instead of chains along [001] is found to be responsible for the stabilization of this superstructure. Highlights: • Nb{sub 2}FeB{sub 2} is predicted to order antiferromagnetically. • Ferromagnetic interactions found in iron chains and antiferromagnetic ones between them. • Unknown “Nb{sub 2}RuB{sub 2}” predicted to crystallize with a twofold U{sub 3}Si{sub 2} superstructure. • Puckering of Nb-layer and Ru-dumbbell formation responsible for superstructure occurrence.

  20. Proposal to negotiate a collaboration agreement related to the application of novel cavity fabrication techniques and Nb/Cu sputter coating technology in the field of superconducting RF for the Future Circular Collider (FCC) study

    E-Print Network [OSTI]

    2015-01-01T23:59:59.000Z

    Proposal to negotiate a collaboration agreement related to the application of novel cavity fabrication techniques and Nb/Cu sputter coating technology in the field of superconducting RF for the Future Circular Collider (FCC) study

  1. Nickel Alloy, Corrosion and Heat-Resistant, Sheet, Strip, and Plate 72Ni - 15.5Cr - 0.95Cb(Nb) - 2.5Ti - 0.70Al - 7.0Fe Annealed

    E-Print Network [OSTI]

    SAE Aerospace Standards. London

    2012-01-01T23:59:59.000Z

    Nickel Alloy, Corrosion and Heat-Resistant, Sheet, Strip, and Plate 72Ni - 15.5Cr - 0.95Cb(Nb) - 2.5Ti - 0.70Al - 7.0Fe Annealed

  2. NCBI Handout Series | Clone DB | Last Update: August 19, 2013 Contact: info@ncbi.nlm.nih.gov Repository for DNA clones with integrated information on sequences, maps and distributors

    E-Print Network [OSTI]

    Levin, Judith G.

    terms are automatically entered in the query box (F). Clicking the "Add to history" link (G) pre- views box so custom terms such as a search history (#9) can be added. Displaying the search results A search for accessing data from CloneDB: Text searching through the Clone DB homepage www.ncbi.nlm.nih.gov/clone/ Bulk

  3. Optical breakdown threshold in nanosecond high repetition second harmonic generation by periodically poled Mg-doped LiTaO{sub 3} crystal

    SciTech Connect (OSTI)

    Louchev, Oleg A.; Wada, Satoshi [Center for Advanced Photonics, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)] [Center for Advanced Photonics, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Hatano, Hideki; Kitamura, Kenji [Division of Environment and Energy Materials, National Institute for Materials Science (NIMS) 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)] [Division of Environment and Energy Materials, National Institute for Materials Science (NIMS) 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2013-08-26T23:59:59.000Z

    Our study shows that a local temperature increase of ?1 K in the crystal lattice caused by second harmonic generation (SHG) and two-photon absorption of 532 nm radiation at the rear of periodically poled stoichiometric LiTaO{sub 3} crystal by changing spontaneous polarization induces a pyroelectric field ?10 kV/cm, accelerating free electrons to an energy of ?10 eV, followed by optical breakdown and crystal damage. Theoretical analysis leads to an explicit expression for the threshold laser fluence of optical breakdown giving ?1.2 J/cm{sup 2} for 1064 nm input radiation in 6.8 kHz pulsed SHG operation, agreeing well with the experimentally found value ?1.32 J/cm{sup 2}.

  4. Coupled Li{sup 1+}/Nb{sup 5+} and O{sup 2-}/F{sup -} ordering on the Na and Cl sites of the average NaCl structure of Li{sub 4}NbO{sub 4}F

    SciTech Connect (OSTI)

    Noren, Lasse [Research School of Chemistry, Australian National University, Canberra, ACT 0200 (Australia); Withers, Ray L., E-mail: withers@rsc.anu.edu.a [Research School of Chemistry, Australian National University, Canberra, ACT 0200 (Australia); Goossens, Darren J. [Research School of Chemistry, Australian National University, Canberra, ACT 0200 (Australia); Elcombe, Margaret; Kearley, Gordon J. [Bragg Institute, Building 87, Australian Nuclear Science and Technology Organisation, PMB, Menai, NSW 2234 (Australia)

    2009-05-15T23:59:59.000Z

    The average, as well as the cation and anion 'disordered', crystal structure of Li{sub 4}NbO{sub 4}F has been carefully investigated via coupled neutron and X-ray powder diffraction studies as well as via electron diffraction studies. The existence of a spectacular highly structured diffuse intensity distribution in the latter provides strong evidence for coupled Li{sup 1+}/Nb{sup 5+} and O{sup 2-}/F{sup -} ordering on the Na and Cl sites of the average NaCl structure of Li{sub 4}NbO{sub 4}F. Bond valence sum calculations have been used to investigate local crystal chemistry as well as to suggest plausible local crystal chemical constraints while ab initio DFT based theoretical calculations of a 2x2x2 supercell have been carried out in order to provide additional insight into the local crystal chemistry of this compound. - Graphical abstract: An <001> zone axis EDP typical of Li{sub 4}NbO{sub 4}F.

  5. The elastic and piezoelectric properties of tungsten bronze ferroelectric crystals ,,Sr0.7Ba0.3...2NaNb5O15 and ,,Sr0.3Ba0.7...2NaNb5O15

    E-Print Network [OSTI]

    Cao, Wenwu

    The elastic and piezoelectric properties of tungsten bronze ferroelectric crystals ,,Sr0.7Ba0 and piezoelectric constants of tungsten bronze ferroelectric crystals Sr0.7Ba0.3 2NaNb5O15 SBNN70 and Sr0.3Ba0.7 2Na. INTRODUCTION Ferroelectric crystals with tungsten bronze structure are another attractive family beside

  6. An R&D Approach to the Development of Long Nb3Sn Accelerator Magnets Using the key and Bladder Technology

    SciTech Connect (OSTI)

    Bartlett, S. E.; Caspi, S.; Dietderich, D. R.; Ferracin, P.; Gourlay, S. A.; Hannaford, C. R.; Hafalia, A. R.; Lietzke, A. F.; McInturff, A. D.; Mattafirri, S.; Sabbi, G.; Scanlan, R. M.

    2004-08-01T23:59:59.000Z

    Building accelerator quality magnets using Nb{sub 3}Sn for next generation facilities is the challenge of the next decade. The Superconducting Magnet Group at LBNL has developed an innovative support structure for high field magnets. The structure is based on an aluminum shell over iron yokes using hydraulic bladders and locking keys for applying the pre-stress. At cool down the pre-stress is almost doubled due to the differences of thermal contraction. This new structure allows precise control of the pre-stress with minimal spring back and conductor over-stress. At present the support structure has been used with prototype magnets up to one meter in length. In this paper, the design of a 4-meter long, 11 Tesla, wind-and-react racetrack dipole will be presented as a possible step toward the fabrication of long Nb{sub 3}Sn accelerator magnets.

  7. Test Results of LARP 3.6 m Nb3Sn Racetrack Coils Support by Full-length and Segmented Shell Structures

    SciTech Connect (OSTI)

    Muratore, Joseph F.; Ambrosio, Giorgio; Anerella, Michael; Barzi, Emanuela; Bossert, Rodger; Caspi, Shlomo; Cheng, D. W.; Cozzolino, John; Dietderich, Daniel R.; Escallier, John; Feher, Sandor; Felice, Helene; Ferracin, Paolo; Ganetis, George; Ghosh, Arup K.; Gupta, Ramesh C.; Hafalia, A. R.; Hannaford, C. R.; Joshi, Piyush; Kovach, Paul; Lietzke, A. F.; Louie, Wing; Marone, Andrew; McInturff, Al D.; Nobrega, F.; Sabbi, GianLuca; Schmalzle, Jesse; Thomas, Richard; Turrioni, Daniele; Wanderer, Peter

    2008-08-17T23:59:59.000Z

    As part of the LHC Accelerator Research Program (LARP) to build a high performance quadrupole magnet with Nb{sub 3}Sn conductor, a pair of 3.6 m-long Nb{sub 3}Sn racetrack coils has been made at Brookhaven National Laboratory (BNL) and installed in two shell-type support structures built by Lawrence Berkeley National Laboratory (LBL). These magnet assemblies have been tested at 4.5 K at BNL to gauge the effect of extended length and prestress on the mechanical performance of the long structure compared to earlier short models. This paper presents the results of quench testing and compares the overall performance of the two versions of the support structure. We also summarize the shell strain measurements and discuss the variation of quench current with ramp rate.

  8. DUAL MAGNUM COMBINATIONS FOR YELLOW NUTSEDGE (Cyperus esculentus L.) MANAGEMENT IN WEST TEXAS PEANUT. B.L. Porter*, P.A. Dotray, J.W. Keeling, and T.A. Baughman.

    E-Print Network [OSTI]

    Mukhtar, Saqib

    DUAL MAGNUM COMBINATIONS FOR YELLOW NUTSEDGE (Cyperus esculentus L.) MANAGEMENT IN WEST TEXAS PEANUT. B.L. Porter*, P.A. Dotray, J.W. Keeling, and T.A. Baughman. Texas Tech University, Texas Agricultural Experiment Station, Lubbock, and Texas Agricultural Extension Service, Vernon. ABSTRACT Field

  9. The Flexible Display CenTer aT arizona sTaTe UniversiTy The U.S. Army established the Flexible Display Center at ASU in February 2004 to spearhead the next revolution in

    E-Print Network [OSTI]

    Rhoads, James

    The Flexible Display CenTer aT arizona sTaTe UniversiTy The U.S. Army established the Flexible development, innovation and integration to create a new generation of innovative displays that will be flexible, lightweight, low power, and rugged. These revolutionary displays will usher in a new era

  10. Fabrication and Test of a Nb3Sn Model Magnet With Ceramic Insulation for the Next Generation Undulator of the LHC

    E-Print Network [OSTI]

    Elias, N; Dalexandro, N; Giloux, C; Bordini, B; Maccaferri, R

    2010-01-01T23:59:59.000Z

    The future run of the Large Hadron Collider with lead ions will require important modifications in the synchrotron radiation profile monitor system, which at present comprises two superconducting undulators wound from Nb-Ti conductor, delivering 5 T in a 60 mm gap, and with a period of 280 mm. Whilst the gap and the nominal field of the future undulators will remain the same, the period shall be 140 mm, which translates to a peak field of over 8 T in the coils and hence requires the use of Nb3Sn technology. In this paper the electromagnetic design of the undulator is summarized. We describe the fabrication of a race-track coil wound with a 0.8 mm diameter Nb3Sn strand with ceramic insulation. Finally, the results of successful tests made at 4.3 K and 1.9 K in a mirror configuration are presented. 10 T at 4.3 K and 11.5 T at 1.9 K were measured in the yoke gap, thus validating this concept for the future undulator.

  11. Four magnetic DB white dwarfs discovered by the Hamburg/ESO survey

    E-Print Network [OSTI]

    D. Reimers; S. Jordan; V. Beckmann; N. Christlieb; L. Wisotzki

    1998-07-14T23:59:59.000Z

    We report on seven peculiar faint blue stars found in the course of the Hamburg/ESO survey (HES) which appear to be magnetic white dwarfs (WDs) with non-hydrogen spectra. We show in particular that four of them (HE 0338-3853, HE 0107-0158, HE 0026-2150, and HE 0003-5701) have He I lines split by magnetic fields of roughly 20MG, since the \\pi components of He I 5876 Angstroem and He I 4929 Angstroem can be identified unambiguously in their spectra, and the $\\sigma^+$, $\\sigma^-$ components can be identified in the spectra of two of these stars (HE 0338-3853 and HE 0003-5701). Besides GD 229, these are the first magnetic DB white dwarfs discovered so far. In addition, three further WDs with broad, unidentifiable features have been found: HE 1043-0502, HE 0236-2656, and HE 0330-0002. We argue that in all three of these stars H I can not be responsible for the broad features, and He I most probably not for the features in HE 0236-2656 and HE 0330-0002, while it still remains possible that the broad features of HE 1043-0502 are due to He I.

  12. Cation ordering transformations in Ba(Mg{sub 1/3}Ta{sub 2/3})O{sub 3}-BaZrO{sub 3} perovskite solid solutions

    SciTech Connect (OSTI)

    Chai, L.; Akbas, M.A.; Davies, P.K. [Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Materials Science and Engineering] [Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Materials Science and Engineering; Parise, J.B. [Univ. of New York, Stony Brook, NY (United States). Dept. of Earth and Space Sciences] [Univ. of New York, Stony Brook, NY (United States). Dept. of Earth and Space Sciences

    1997-09-01T23:59:59.000Z

    The effect of the substitution of BaZrO{sub 3} on the cation ordering in Ba(Mg{sub 1/3}Ta{sub 2/3})O{sub 3} was studied using TEM and X-ray and neutron diffraction. Almost no solubility of Zr was found in the 1:2 ordered, trigonal structure of the Ba(Mg{sub 1/3}Ta{sub 2/3})O{sub 3} end-member (P{bar 3}m1), and a transformation to a 1:1 ordered, cubic (Fm{bar 3}m) phase with a = 2a{sub per} occurs for substitution levels between {approximately}10 and 25 mol% BaZrO{sub 3}. The structure of this Ba({beta}{prime}{sub 1/2}{beta}{double_prime}{sub 1/2})O{sub 3}-type phase consists of two distinct octahedral sites, {beta}{prime} and {beta}{double_prime}. The occupancies of the two cation positions, refined using the Rietveld method, were found to be consistent with a random site model in which {beta}{double_prime} is occupied by Ta, and {beta}{prime} by a random distribution of the remaining cations. The homogeneity range of the 1:1 solid solutions predicted by this model, Ba{l_brace}[Mg{sub (2{minus}y)/3} Ta{sub (1{minus}2y)/3} Zr{sub y}]{sub 1/2}[Ta]{sub 1/2}{r_brace}O{sub 3} (0.0 < y {le} 0.5), is in excellent agreement with that observed experimentally.

  13. Tunneling spectroscopy of superconducting MoN and NbTiN grown by atomic layer deposition

    SciTech Connect (OSTI)

    Groll, Nickolas R., E-mail: ngroll@anl.gov; Klug, Jeffrey A.; Claus, Helmut; Pellin, Michael J.; Proslier, Thomas, E-mail: proslier@anl.gov [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Cao, Chaoyue; Becker, Nicholas G.; Zasadzinski, John F. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, Illinois Institute of Technology, Chicago, Illinois 60616 (United States); Altin, Serdar [Fen Edebiyat Fakultesi, Fizik Bolumu, Inonu Universitesi, 44280 Malatya (Turkey)

    2014-03-03T23:59:59.000Z

    A tunneling spectroscopy study is presented of superconducting MoN and Nb{sub 0.8}Ti{sub 0.2}N thin films grown by atomic layer deposition (ALD). The films exhibited a superconducting gap of 2?meV and 2.4?meV, respectively, with a corresponding critical temperature of 11.5?K and 13.4?K, among the highest reported T{sub c} values achieved by the ALD technique. Tunnel junctions were obtained using a mechanical contact method with a Au tip. While the native oxides of these films provided poor tunnel barriers, high quality tunnel junctions with low zero bias conductance (below ?10%) were obtained using an artificial tunnel barrier of Al{sub 2}O{sub 3} on the film's surface grown ex situ by ALD. We find a large critical current density on the order of 4?×?10{sup 6}?A/cm{sup 2} at T?=?0.8T{sub c} for a 60?nm MoN film and demonstrate conformal coating capabilities of ALD onto high aspect ratio geometries. These results suggest that the ALD technique offers significant promise for thin film superconducting device applications.

  14. Fabrication and test of 4m long Nb3Sn quadrupole coil made of RRP-114-127 strand

    SciTech Connect (OSTI)

    Bossert, R.; Ambrosio, G.; Andreev, N.; Barzi, E.; Chlachidze, G.; Kashikhin, V.V.; Lamm, M.; Nobrega, A.; Novitski, I.; Orris, D.; Tartaglia, M.; /Fermilab

    2011-06-01T23:59:59.000Z

    Fermilab is collaborating with LBNL and BNL (US-LARP collaboration) to develop a large-aperture Nb{sub 3}Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade. Several two-layer quadrupole models of the 1-meter and 3.4-meter length with 90mm apertures have been fabricated and tested by the US-LARP collaboration. High-Jc RRP-54/61 strand was used for nearly all models. Large flux jumps typical for this strand due to the large sub-element diameter limited magnet quench performance at temperatures below 2.5-3K. This paper summarizes the fabrication and test by Fermilab of LQM01, a long quadrupole coil test structure (quadrupole mirror) with the first 3.4m quadrupole coil made of more stable RRP-114/127 strand. The coil and structure are fully instrumented with voltage taps, full bridge strain gauges and strip heaters to monitor preload, thermal properties and quench behavior. Measurements during fabrication are reported, including preload during the yoke welding process. Testing is done at 4.5K, 1.9K and a range of intermediate temperatures. The test results include magnet strain and quench performance during training, as well as quench studies of current ramp rate and temperature dependence from 1.9K to 4.5K.

  15. Surface electronic structure for various surface preparations of Nb-doped SrTiO{sub 3} (001)

    SciTech Connect (OSTI)

    Hatch, Richard C.; Fredrickson, Kurt D.; Choi, Miri; Lin, Chungwei; Seo, Hosung; Posadas, Agham B.; Demkov, Alexander A. [Department of Physics, The University of Texas at Austin, Austin, Texas 78712 (United States)] [Department of Physics, The University of Texas at Austin, Austin, Texas 78712 (United States)

    2013-09-14T23:59:59.000Z

    High-resolution angle-resolved photoemission spectroscopy (ARPES) was used to study the surface electronic structure of Nb-doped SrTiO{sub 3} (STO) single crystals prepared using a variety of surface preparations. ARPES measurements show that simple degreasing with subsequent anneal in vacuum is not an adequate surface preparation of STO, rather, preparations consisting of etching with buffered HF or HCl, and to a lesser extent, simple water leaching resulted in surfaces with much less disorder. A non-dispersing, mid-gap state was found ?800 meV above the top of the valence band for samples which underwent etching. This mid-gap state is not present for vacuum-annealed and water-leached samples, as well as for STO thin films grown using molecular beam epitaxy. Theoretical modeling using density functional theory suggests that this mid-gap state is not related to the SrO- and TiO{sub 2}-terminated surfaces, but rather, is due to a partial hydrogenation of the STO surface that occurs during etching.

  16. Radiation damage by light- and heavy-ion bombardment of single-crystal LiNbO?

    SciTech Connect (OSTI)

    Huang, Hsu-Cheng [Columbia Univ., New York, NY (United States); Zhang, Lihua [Brookhaven National Lab. (BNL), Upton, NY (United States); Malladi, Girish [SUNY Polytechnic Inst., Albany, NY (United States); Dadap, Jerry I. [Columbia Univ., New York, NY (United States); Manandhar, Sandeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kisslinger, Kim [Brookhaven National Lab. (BNL), Upton, NY (United States); Vemuri, Rama Sesha R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Shutthanandan, Vaithiyalingam [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bakhru, Hassaram [SUNY Polytechnic Inst., Albany, NY (United States); Osgood, Jr., Richard M. [Columbia Univ., New York, NY (United States)

    2015-01-01T23:59:59.000Z

    In this work, a battery of analytical methods including in situ RBS/C, confocal micro-Raman, TEM/STEM, EDS, AFM, and optical microscopy were used to provide a comparative investigation of light- and heavy-ion radiation damage in single-crystal LiNbO?. High (~MeV) and low (~100s keV) ion energies, corresponding to different stopping power mechanisms, were used and their associated damage events were observed. In addition, sequential irradiation of both ion species was also performed and their cumulative depth-dependent damage was determined. It was found that the contribution from electronic stopping by high-energy heavy ions gave rise to a lower critical fluence for damage formation than for the case of low-energy irradiation. Such energy-dependent critical fluence of heavy-ion irradiation is two to three orders of magnitude smaller than that for the case of light-ion damage. In addition, materials amorphization and collision cascades were seen for heavy-ion irradiation, while for light ion, crystallinity remained at the highest fluence used in the experiment. The irradiation-induced damage is characterized by the formation of defect clusters, elastic strain, surface deformation, as well as change in elemental composition. In particular, the presence of nanometric-scale damage pockets results in increased RBS/C backscattered signal and the appearance of normally forbidden Raman phonon modes. The location of the highest density of damage is in good agreement with SRIM calculations. (author)

  17. Design modifications, fabrication and test of HFDB-03 racetrack magnet wound with pre-reacted Nb3Sn Rutherford cable

    SciTech Connect (OSTI)

    Giorgio Ambrosio et al.

    2003-10-07T23:59:59.000Z

    A 10 T racetrack magnet (HFDB-03) wound with pre-reacted Nb{sub 3}Sn Rutherford cable has been fabricated and tested at Fermilab. This magnet is the third one in a proof-of-principle series for the use of the React-and-Wind technology in common-coil dipole magnets for future accelerators. It consists of two flat racetrack coils (28 turns each) separated by 5 mm. The maximum field on the coil, at the short sample limit of 16530 A, is 10 tesla. The cable has 41 strands with 0.7 mm diameter and the minimum bend radius in the magnet ends is 90 mm. The predecessor of this magnet (HFDB-02) reached 78% of the short sample limit at 7.7 T. The mechanical design was improved and the fabrication procedure was slightly modified in order to address possible causes of limitation. In this paper we present the mechanical design and analysis of HFDB-03, the modifications to the fabrication procedure and the test results.

  18. Assembly and Test of SQ01b, a Nb3Sn Quadrupole Magnet for the LHC Accelerator Research Program

    SciTech Connect (OSTI)

    Ferracin, P.; Ambrosio, G.; Bartlett, S. E.; Bordini, B.; Carcagno, R.H.; Caspi, S.; Dietderich, D.R.; Feher, S.; Gourlay, S.A.; Hafalia, A.R.; Lamm, M.J.; Lietzke, A.F.; Mattafirri, S.; McInturff, A.D.; Orris, D.F.; Pischalnikov, Y.M.; Sabbi, G.L.; Sylvester, C.D.; Tartaglia, M.A.; Velev, G.V.; Zlobin, A.V.; Kashikhin, V.V.

    2006-06-01T23:59:59.000Z

    The US LHC Accelerator Research Program (LARP) consists of four US laboratories (BNL, FNAL, LBNL, and SLAC) collaborating with CERN to achieve a successful commissioning of the LHC and to develop the next generation of Interaction Region magnets. In 2004, a large aperture Nb{sub 3}Sn racetrack quadrupole magnet (SQ01) has been fabricated and tested at LBNL. The magnet utilized four subscale racetrack coils and was instrumented with strain gauges on the support structure and directly over the coil's turns. SQ01 exhibited training quenches in two of the four coils and reached a peak field in the conductor of 10.4 T at a current of 10.6 kA. After the test, the magnet was disassembled, inspected with pressure indicating films, and reassembled with minor modifications. A second test (SQ01b) was performed at FNAL and included training studies, strain gauge measurements and magnetic measurements. Magnet inspection, test results, and magnetic measurements are reported and discussed, and a comparison between strain gauge measurements and 3D finite element computations is presented

  19. Processing of Bi-2212 and Nb$_3$Sn studied in situ by high energy synchrotron diffraction and micro-tomography

    E-Print Network [OSTI]

    Kadar, Julian

    Next generation superconducting wires have been studied to obtain more information on the evolution of phase growth, crystallite size and strain state during wire processing. The high energy scattering beam line ID15 at the European Synchrotron Radiation Facility provides a very high flux of high energy photons for very fast in situ X-ray diffraction and micro-tomography studies of Bi-2212/Ag and Nb$_3$S/Cu wire samples. The typical wire processing conditions could be imitated in the X-ray transparent furnace at ID15 for diffraction and tomography studies. Efficient data analysis is mandatory in order to handle the very fast data acquisition rate. For this purpose an Excel-VBA based program was developed that allows a semi-automated fitting and tracking of peaks with pre-set constraints. With this method, more than one thousand diffraction patterns have been analysed to extract d-spacing, peak intensity and peak width values. X ray absorption micro tomograms were recorded simultaneously with the X-ray diffrac...

  20. Heating Greenhouses1 D.E. Buffington, R.A. Bucklin, R.W. Henley and D.B. McConnell2

    E-Print Network [OSTI]

    Watson, Craig A.

    AE11 Heating Greenhouses1 D.E. Buffington, R.A. Bucklin, R.W. Henley and D.B. McConnell2 1 supplemental heat is required. Obviously there are many ways this can be accomplished from the standpoint of these factors be considered when selecting and installing a heating system. HEATING SYSTEMS Greenhouse heating

  1. To appear in A. Ram & D.B. Leake, editors, Goal-Driven Learning, MIT Press/Bradford Books. Learning as Goal-Driven Inference

    E-Print Network [OSTI]

    Michalski, Ryszard S.

    "toolbox"), the inferential theory of learning proposes a taxonomy of the types of inferencesTo appear in A. Ram & D.B. Leake, editors, Goal-Driven Learning, MIT Press/Bradford Books. Chapter 21 Learning as Goal-Driven Inference Ryszard S. Michalski and Ashwin Ram 1 Inferential Theory

  2. How to implement decoy-state quantum key distribution for a satellite uplink with 50-dB channel loss

    SciTech Connect (OSTI)

    Meyer-Scott, Evan; Yan, Zhizhong; MacDonald, Allison; Bourgoin, Jean-Philippe; Huebel, Hannes; Jennewein, Thomas [Institute for Quantum Computing, University of Waterloo, 200 University Avenue W, Waterloo ON, Canada N2L 3G1 (Canada)

    2011-12-15T23:59:59.000Z

    Quantum key distribution (QKD) takes advantage of fundamental properties of quantum physics to allow two distant parties to share a secret key; however, QKD is hampered by a distance limitation of a few hundred kilometers on Earth. The most immediate solution for global coverage is to use a satellite, which can receive separate QKD transmissions from two or more ground stations and act as a trusted node to link these ground stations. In this article we report on a system capable of performing QKD in the high loss regime expected in an uplink to a satellite using weak coherent pulses and decoy states. Such a scenario profits from the simplicity of its receiver payload, but has so far been considered to be infeasible due to very high transmission losses (40-50 dB). The high loss is overcome by implementing an innovative photon source and advanced timing analysis. Our system handles up to 57 dB photon loss in the infinite key limit, confirming the viability of the satellite uplink scenario. We emphasize that while this system was designed with a satellite uplink in mind, it could just as easily overcome high losses on any free space QKD link.

  3. Radiation damage by light- and heavy-ion bombardment of single-crystal LiNbO?

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Huang, Hsu-Cheng; Zhang, Lihua; Malladi, Girish; Dadap, Jerry I.; Manandhar, Sandeep; Kisslinger, Kim; Vemuri, Rama Sesha R.; Shutthanandan, Vaithiyalingam; Bakhru, Hassaram; Osgood, Jr., Richard M.

    2015-01-01T23:59:59.000Z

    In this work, a battery of analytical methods including in situ RBS/C, confocal micro-Raman, TEM/STEM, EDS, AFM, and optical microscopy were used to provide a comparative investigation of light- and heavy-ion radiation damage in single-crystal LiNbO?. High (~MeV) and low (~100s keV) ion energies, corresponding to different stopping power mechanisms, were used and their associated damage events were observed. In addition, sequential irradiation of both ion species was also performed and their cumulative depth-dependent damage was determined. It was found that the contribution from electronic stopping by high-energy heavy ions gave rise to a lower critical fluence for damage formationmore »than for the case of low-energy irradiation. Such energy-dependent critical fluence of heavy-ion irradiation is two to three orders of magnitude smaller than that for the case of light-ion damage. In addition, materials amorphization and collision cascades were seen for heavy-ion irradiation, while for light ion, crystallinity remained at the highest fluence used in the experiment. The irradiation-induced damage is characterized by the formation of defect clusters, elastic strain, surface deformation, as well as change in elemental composition. In particular, the presence of nanometric-scale damage pockets results in increased RBS/C backscattered signal and the appearance of normally forbidden Raman phonon modes. The location of the highest density of damage is in good agreement with SRIM calculations. (author)« less

  4. CdS thin films on LiNbO{sub 3} (1 0 4) and silicon (1 1 1) substrates prepared through an atom substitution method

    SciTech Connect (OSTI)

    Qin Haiming; Zhao Yue [State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100 (China); Liu Hong, E-mail: hongliu@sdu.edu.c [State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100 (China); Gao Zheng [State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100 (China); Wang Jiyang, E-mail: Jywang@sdu.edu.c [State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100 (China); Liu Duo; Sang Yuanhua; Yao Bin [State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100 (China); Boughton, Robert I. [Center for Material Science, Bowling Green State University, Bowling Green, OH 43403 (United States)

    2011-03-15T23:59:59.000Z

    CdS thin films on LiNbO{sub 3} (1 0 4) and silicon (1 1 1) substrates were prepared through an atom substitution technique using cadmium nitrate as a reactant in an H{sub 2}S atmosphere at 230 {sup o}C. X-ray diffraction, scanning electron microscopy and transmission microscopy results indicate that the CdS film grows on LiNbO{sub 3} oriented along the [0 0 1] axis in form of crystallized nanoplates, while that deposited on silicon forms randomly oriented nanoparticles. Investigation of the precursor thin film suggests that CdS forms from the O in the CdO precursor thin film being substituted by S from H{sub 2}S in the surrounding environment, which is designated as an atom substitution process. This novel method involving an atom substitution reaction between the CdO precursor thin film and its environment can provide a new low cost approach to the preparation of chalcogenide or other compound thin films. A schematic illustration and corresponding mechanism describing the details of this method are proposed. -- Graphical abstract: Elemental O in CdO is substituted by elemental S from the atmosphere in the apparatus, which is designated as an atom substitution process. This novel method involving an atom substitution reaction between the CdO precursor thin film and its environment can provide a new low cost approach to the preparation of chalcogenide or other compound thin films. Display Omitted Research highlights: {yields} An atom substitution method for thin film preparation was demonstrated. {yields} Combination of the atom substitution and spin coating method was achieved. {yields} Well oriented CdS thin film was prepared on LiNbO{sub 3} substrate. {yields} The atom substitution method could be used for many compound systems.

  5. Excitation functions of the nat-Ta(p,x)178m2Hf and nat-W(p,x)178m2Hf reactions at energies up to 2600 MeV

    E-Print Network [OSTI]

    Titarenko, Yu E; Pavlov, K V; Titarenko, A Yu; Zhivun, V M; Chauzova, M V; Ignatyuk, A V; Mashnik, S G; Leray, S; Boudard, A; David, J -C; Mancusi, D; Cugnon, J; Yariv, Y; Nishihara, K; Matsuda, N; Kumawat, H; Stankovsky, A Yu

    2015-01-01T23:59:59.000Z

    Due to potential level of energy intensity 178m2Hf is an extremely interesting isomer. One possible way to produce this isomer is irradiation of nat-Ta or nat-W samples with high energy protons. Irradiation of nat-Ta and nat-W samples performed for other purposes provides an opportunity to study the corresponding reactions. This paper pre-sents the 178m2Hf independent production cross sections for both targets measured by the gamma-ray spectrometry method. The reaction excitation functions have been obtained for the proton energies from 40 up to 2600 MeV. The experimental results were compared with calculations by various versions of the intranuclear cascade model in the well-known codes: ISABEL, Bertini, INCL4.5+ABLA07, PHITS, CASCADE07 and CEM03.02. The isomer ratio for the nat-Ta(p,x)178m2Hf reaction is evaluated on the basis of the available data.

  6. Excitation functions of the nat-Ta(p,x)178m2Hf and nat-W(p,x)178m2Hf reactions at energies up to 2600 MeV

    E-Print Network [OSTI]

    Yu. E. Titarenko; V. F. Batyaev; K. V. Pavlov; A. Yu. Titarenko; V. M. Zhivun; M. V. Chauzova; A. V. Ignatyuk; S. G. Mashnik; S. Leray; A. Boudard; J. -C. David; D. Mancusi; J. Cugnon; Y. Yariv; K. Nishihara; N. Matsuda; H. Kumawat; A. Yu. Stankovsky

    2015-04-30T23:59:59.000Z

    Due to potential level of energy intensity 178m2Hf is an extremely interesting isomer. One possible way to produce this isomer is irradiation of nat-Ta or nat-W samples with high energy protons. Irradiation of nat-Ta and nat-W samples performed for other purposes provides an opportunity to study the corresponding reactions. This paper pre-sents the 178m2Hf independent production cross sections for both targets measured by the gamma-ray spectrometry method. The reaction excitation functions have been obtained for the proton energies from 40 up to 2600 MeV. The experimental results were compared with calculations by various versions of the intranuclear cascade model in the well-known codes: ISABEL, Bertini, INCL4.5+ABLA07, PHITS, CASCADE07 and CEM03.02. The isomer ratio for the nat-Ta(p,x)178m2Hf reaction is evaluated on the basis of the available data.

  7. Photorefractive properties of Ce- and Ca-doped Sr/sub 0. 6/Ba/sub 0. 4/Nb/sub 2/O/sub 6/

    SciTech Connect (OSTI)

    Rakuljic, G.A.; Sayano, K.; Agranat, A.; Yariv, A.; Neurgaonkar, R.R.

    1988-10-17T23:59:59.000Z

    We present the results of experimental study of the absorption coefficient, two-beam photorefractive coupling constant, and photorefractive response time of a doubly Ce- and Ca-doped Sr/sub 0.6/Ba/sub 0.4/Nb/sub 2/O/sub 6/. This crystal displays enhanced photorefractive response at near infrared wavelengths when compared to Ce-doped SBN:60. The temperature dependence of the coupling constant over the range from -30 to 40 /sup 0/C has also been studied.

  8. Buffered Electropolishing – A New Way for Achieving Extremely Smooth Surface Finish on Nb SRF Cavities to be Used in Particle Accelerators

    SciTech Connect (OSTI)

    Hui Tian, Charles Reece, Michael Kelley

    2009-05-01T23:59:59.000Z

    Future accelerators require unprecedented cavity performance, which is strongly influenced by interior surface nano-smoothness. Electropolishing (EP) is the technique of choice to be developed for high-field superconducting radio frequency (SRF) cavities. Electrochemical impedance spectroscopy (EIS) and related techniques point to the electropolishing mechanism of Nb in a sulphuric and hydrofluoric acid electrolyte controlled by a compact surface salt film under F- diffusion-limited mass transport control. These and other findings are guiding a systematic characterization to form the basis for cavities process optimization.

  9. Structural studies of SrFeO{sub 3} and SrFe{sub 0.5}Nb{sub 0.5}O{sub 3} by employing XRD and XANES spectroscopic techniques

    SciTech Connect (OSTI)

    Akhtar, M. Javed, E-mail: javeda@pinstech.org.pk; Khan, R. Tahir Ali

    2011-10-15T23:59:59.000Z

    The perovskite based SrFeO{sub 3} and SrFe{sub 0.5}Nb{sub 0.5}O{sub 3} materials have been synthesized by solid state reaction methods. The structural properties are investigated using a combination of X-ray diffraction and X-ray absorption fine structure spectroscopic techniques. From the Rietveld refinement of the X-ray diffraction data it has been observed that SrFeO{sub 3} has a simple cubic perovskite structure, which is consistent with the previous literature results; whereas SrFe{sub 0.5}Nb{sub 0.5}O{sub 3} shows a tetragonal structure within P4mm space group. X-ray absorption results demonstrate that the valence state of Fe in SrFeO{sub 3} is (IV); however, it changes to (III) when 50% Nb{sup 5+} is substituted at the Fe sites. - Highlights: {yields} Structural studies by employing XRD and XANES spectroscopic techniques. {yields} Rietveld refinement confirmed SrFeO{sub 3} has cubic structure, space group Pm-3m. {yields} It is revealed that SrFe{sub 0.5}Nb{sub 0.5}O{sub 3} has tetragonal structure, in P4mm space group. {yields} From XANES results it is observed that Fe has valence state of (IV) in SrFeO{sub 3}. {yields} Doping of 50% Nb{sup 5+} at Fe sites, changes Fe valence to (III) in SrFe{sub 0.5}Nb{sub 0.5}O{sub 3}.

  10. Structure and dielectric properties of Ba{sub 5}NdCu{sub 1.5}Nb{sub 8.5}O{sub 30??} tungsten bronze ceramics

    SciTech Connect (OSTI)

    Tan, Yan-Qing; Yu, Yuan [College of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, 19(A) Yu Quan Road, Beijing 100049 (China); Hao, Yong-Mei, E-mail: ymhao@ucas.ac.cn [College of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, 19(A) Yu Quan Road, Beijing 100049 (China); Dong, Su-Ying; Yang, Yi-Wen [Beijing National Day School, 66 Yu Quan Road, Beijing 100039 (China)

    2013-05-15T23:59:59.000Z

    Highlights: ? Tetragonal tungsten bronze ceramic Ba{sub 5}NdCu{sub 1.5}Nb{sub 8.5}O{sub 30??} was prepared. ? Titanium was replaced by copper in M{sub 5}RTi{sub 3}Nb{sub 7}O{sub 30} for the first time. ? Detailed structural information was retrieved by Rietveld refinement. ? An obvious relaxor-like dielectric behavior was observed in this ceramic, ion disorders in A1 and B sites contribute to this behavior. - Abstract: A new type of tungsten bronze ceramic Ba{sub 5}NdCu{sub 1.5}Nb{sub 8.5}O{sub 30??} has been prepared by a conventional solid-state reaction technique. Its structural, dielectric properties were investigated. Rietveld analysis shows that Ba{sub 5}NdCu{sub 1.5}Nb{sub 8.5}O{sub 30??} has a single-phase tetragonal (space group P4bm and lattice constants a = b = 12.4961(4) ?, c = 3.9426(8) ?, V = 615.66(4) ?{sup 3}) tungsten bronze structure. The occupations of sites A and B are quite interesting. A1 sites are fully disordered occupied by Ba ions and Nd ions and A2 sites for Ba ions only, while B-sites are equal for both Cu and Nb ions to occupy. This material exhibits an obvious relaxation behavior in the 213–573 K temperature range. The dielectric constants have been fitted by the modified Curie–Weiss law and all the estimated ? values are close to 2, confirming the typical relaxor ferroelectric behavior. The disorders of Ba{sup 2+} or Nd{sup 3+} in A1 sites and Nb{sup 5+}, Cu{sup 2+} in B sites induced by the oxygen vacancies may contribute to this dielectric behavior.

  11. Light scattering from ,,K0.5Na0.5...0.2,,Sr0.75Ba0.25...0.9Nb2O6 with the tungsten bronze structure: An analogy with relaxor ferroelectrics

    E-Print Network [OSTI]

    Light scattering from ,,K0.5Na0.5...0.2,,Sr0.75Ba0.25...0.9Nb2O6 with the tungsten bronze structure a complex single crystal from the tungsten­bronze family, K0.5Na0.5 0.2 Sr0.75Ba0.25 0.9Nb2O6 doped with Cu2 photorefractive material.1 KNSBN originates from the tungsten­bronze family of ferroelectrics. KNSBN has two close

  12. JOURNAL DE PHYSIQUE IV Colloque C3, supplment au Journal de Physique III, Volume 5, avril 1995 C3-217

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    of solidified droplets, including pure metals (W, Re, Ta, Mo, Nb, Ir, Zr) and alloys (W-Re, Mo-Re, Ta diagramme de phases ont été privilégiés : présence de phases complexes a et % (Re-W, Mo-Re) ou existence d surfusions importantes, jusqu'ŕ 900 K pour Re [2], ont été atteintes sur sept métaux : W, Re, Ta, Mo, Nb, Ir

  13. The effect of fluence and irradiation temperature on delayed hydride cracking in Zr-2.5Nb

    SciTech Connect (OSTI)

    Sagat, S.; Coleman, C.E.; Griffiths, M. [AECL Research, Chalk River, Ontario (Canada); Wilkins, B.J.S. [AECL Research, Pinawa, Manitoba (Canada)

    1994-12-31T23:59:59.000Z

    Zirconium alloys are susceptible to a stable cracking process called delayed hydride cracking (DHC). DHC has two stages: (a) crack initiation that requires a minimum crack driving force (the threshold stress intensity factor, K{sub IH}) and (b) stable crack growth that is weakly dependent on K{sub l}. The value of K{sub lH} is an important element in determining the tolerance of components to sharp flaws. The rate of cracking is used in estimating the action time for detecting propagating cracks before they become unstable. Hence, it is important for reactor operators to know how these properties change during service in reactors where the components are exposed to neutron irradiation at elevated temperatures. DHC properties were measured on a number of components, made from the two-phase alloy Zr-2.5 Nb, irradiated at temperatures in the range of 250 to 290 C in fast neutron fluxes (E {>=} 1 MeV) between 1.6 {times} 10{sup 17} and 1.8 {times} 10{sup 18} n/m{sup 2} {center_dot} s to fluences between 0.01 {times} 10{sup 25} and 9.8 {times} 10{sup 25} n/m{sup 2}. The neutron irradiation reduced K{sub IH} by about 20% and increased the velocity of cracking by a factor of about five. The increase in crack velocity was greatest with the lowest irradiation temperature. These changes in the rack velocity by neutron irradiation are explained in terms of the combined effects of irradiation hardening associated with increased -type dislocation density, and {beta}-phase decomposition. While the former process increases crack velocity, the latter process decrease it. The combined contribution is controlled by the irradiation temperature. X-ray diffraction analyses showed that the degree of {beta}-phase decomposition was highest with an irradiation temperature of 290 C while -type dislocation densities were highest with an irradiation temperature of 250 C.

  14. First-principles investigation of the vacancy effect on the electronic properties in M{sub 2}AlC(M = V and Nb)

    SciTech Connect (OSTI)

    Kun, Liu, E-mail: liukunws@163.com; Yuan, Qi [College of Mathematics and Statistics, Long Dong University, QingYang 745000 (China); Ji-Zheng, Duan [Institute of Modern physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2014-10-15T23:59:59.000Z

    First principles calculations have been performed to study the mono-vacancy formation energies and electronic properties of M{sub 2}AlC (M = V and Nb) compound. The results show that the M mono-vacancy has a maximum formation energy. While the C mono-vacancy has a minimum formation energy, which means that the C mono-vacancy is the energetically most favorable in M{sub 2}AlC. The d-electrons of M element contribute most to the DOS of M{sub 2}AlC around the Fermi level, it implies that the conductivity of M{sub 2}AlC comes from the transition metal M. The M-C bond is stronger than the M-Al bond, which is caused by the strong hybridization energy peak between M and C atom. In addition, the M-C bond is weaken in the presence of the M or C mono-vacancy. The cell volumes are reduced when the mono-vacancy is formed. These results help us to understand the origin of the defect-related properties and phase stability of V{sub 2}AlC and Nb{sub 2}AlC under extreme environment.

  15. Enhancement in the multiferroic properties of BiFeO{sub 3} by charge compensated aliovalent substitution of Ba and Nb

    SciTech Connect (OSTI)

    Makhdoom, A. R., E-mail: javedakhtar6@gmail.com, E-mail: a.r.makhdoom@gmail.com; Rafiq, M. A.; Hasan, M. M. [Department of Metallurgy and Materials Engineering, Pakistan Institute of Engineering and Applied Sciences Nilore, Islamabad (Pakistan)] [Department of Metallurgy and Materials Engineering, Pakistan Institute of Engineering and Applied Sciences Nilore, Islamabad (Pakistan); Akhtar, M. J., E-mail: javedakhtar6@gmail.com, E-mail: a.r.makhdoom@gmail.com; Siddique, M.; Iqbal, M. [Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)] [Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)

    2014-03-15T23:59:59.000Z

    Polycrystalline ceramics, Bi{sub 1-2x}Ba{sub 2x}Fe{sub 1-x}Nb{sub x}O{sub 3} (x = 0.00–0.15), were synthesized by solid state reactions method. X-ray diffraction data have revealed elimination of impurity phases and an increase in unit cell volume with Ba and Nb substitution. Diffraction peak splitting is found to be suppressed which indicates a decrease in octahedral distortion. The Mössbauer spectra demonstrate the suppression of spiral spin modulation of the magnetic moments resulting in enhanced ferromagnetism with increasing dopant concentration. The leakage current density of the sample with x = 0.10 is found to be greatly reduced up to six orders of magnitude as compared to the undoped sample. Ohmic conduction is found to be dominant mechanism in all the samples, however, undoped sample showed space charge limited conduction in high electric filed region, while the sample with x = 0.15 exhibited grain boundary limited conduction in low electric field region.

  16. VEHICLE ACCESS PORTALS TA-48 Vicinity TA-36 Vicinity

    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'sis Taking Over OurThe Iron SpinPrincetonUsing Maps to Predict4 VARIATIONS IN THE SOLARJemez

  17. Nanotwins and phases in high-strain Pb,,Mg1/3Nb2/3...1-xTixO3 crystal C.-S. Tu,1,a

    E-Print Network [OSTI]

    that PMN is an incipient FE. Recent first-principles dynamic simulations for Pb Sc1/2Nb1/2 O3 and PMN show and after an electric E -field poling by means of dielectric permittivity, hysteresis loop, domain structure

  18. Optical interband transitions in relaxor-based ferroelectric 0.93Pb,,Zn1/3Nb2/3...O30.07PbTiO3 single crystal

    E-Print Network [OSTI]

    Cao, Wenwu

    Optical interband transitions in relaxor-based ferroelectric 0.93Pb,,Zn1/3Nb2/3...O3­0.07PbTiO3 June 2010 The optical transmission spectrum of 111 c poled relaxor-based ferroelectric single crystal 0. The optical absorption edge has been determined and the wavelength dependence of the absorption coefficient

  19. Single Crystalline NbO2 Nanowire Synthesis Bull. Korean Chem. Soc. 2012, Vol. 33, No. 3 839 http://dx.doi.org/10.5012/bkcs.2012.33.3.839

    E-Print Network [OSTI]

    Kim, Bongsoo

    is employed in proton exchange membrane fuel cell for oxygen-reduction reaction, largely increasing mass solar cells, since the contact between active material and electrolyte becomes excellent due to a large be applied in biotechnology, pharmaceutical industry, and clinical diagnostics, have been reported.20 Nb

  20. Phases and domain structures in tungsten-doped Pb,,Mg1/3Nb2/3...1-xTixO3 ,,x=0.35... crystal

    E-Print Network [OSTI]

    Phases and domain structures in tungsten-doped Pb,,Mg1/3Nb2/3...1-xTixO3 ,,x=0.35... crystal F and piezoelectric response, has the great potential of applications in wireless photoactuators. The tungsten ferroelectric physics of tungsten-doped PMNT single crystals is still unclear. In this study, temperature

  1. IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 9, No. 2, JUNE 1999 4217 New Results for NbN Phonon-CooledHot Electron BolometricMixers Above 1 THz

    E-Print Network [OSTI]

    Massachusetts at Lowell, University of

    (SuperconductivityDivision)under GrantNo.98062, as well as grants from the National ScienceFoundation (ECS-9313920IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 9, No. 2, JUNE 1999 4217 New Results for Nb noise receivers up to at least 700 GHz. Above 1 THz, the thin film superconductor version of the HEB

  2. Cold Fusion Production and Decay of Neutron-Deficient Isotopes of Dubnium and Development of Extraction Systems for Group V Elements

    SciTech Connect (OSTI)

    Gates, Jacklyn M.

    2008-07-31T23:59:59.000Z

    Excitation functions for the 1n and 2n exit channels of the 208Pb(51V,xn)259-xDb reaction were measured. A maximum cross section of the 1n exit channel of 2070+1100/-760 pb was measured at an excitation energy of 16.0 +- 1.8 MeV. For the 2n exit channel, a maximum cross section of 1660+450/-370 pb was measured at 22.0 +- 1.8 MeV excitation energy. The 1n excitation function for the 209Bi(50Ti,n)258Db reaction was remeasured, resulting in a cross section of 5480+1730/1370 pb at an excitation energy of 16.0 +- 1.6 MeV. Differences in cross section maxima are discussed in terms of the fusion probability below the barrier. The extraction of niobium (Nb) and tantalum (Ta) from hydrochloric acid and mixed hydrochloric acid/lithium chloride media by bis(2-ethylhexyl) hydrogen phosphate (HDEHP) and bis(2-ethylhexyl) hydrogen phosphite (BEHP) was studied. The goal of the experiments was to find a system that demonstrates selectivity among the members of group five of the Periodic Table and is also suitable for the study of dubnium (Db, Z = 105). Experiments with niobium and tantalum were performed with carrier (10-6 M), carrier free (10-10 M) and trace (10-16 M) concentrations of metal using hydrochloric acid solution with concentrations ranging from 1 - 11 M. The extraction of niobium and tantalum from mixed hydrochloric acid/lithium chloride media by HDEHP and BEHP as a function of hydrogen ion (H+) concentration was also investigated. The data obtained are used as the basis to discuss the speciation of niobium and tantalum under the conditions studied and to evaluate possible extraction mechanisms. The 74Se(18O,p3n)88gNb excitation function was measured to determine the best energy for producing the 88Nb used in chemistry experiments. A maximum cross section of 495 +- 5 mb was observed at an 18O energy of 74.0 MeV. The half life of 88gNb was measured and determined to be 14.56 +- 0.11 min.

  3. Temperature-dependent oxygen release, intercalation behaviour and catalytic properties of V{sub 2}O{sub 5}.xNb{sub 2}O{sub 5} compounds

    SciTech Connect (OSTI)

    Boerrnert, Carina [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Str. 40, D-01187 Dresden (Germany)] [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Str. 40, D-01187 Dresden (Germany); Zosel, Jens [Kurt-Schwabe-Institut fuer Mess- und Sensortechnik e. V. Meinsberg, Kurt-Schwabe-Str. 4, D-04720 Ziegra-Knobelsdorf (Germany)] [Kurt-Schwabe-Institut fuer Mess- und Sensortechnik e. V. Meinsberg, Kurt-Schwabe-Str. 4, D-04720 Ziegra-Knobelsdorf (Germany); Polte, Annette; Wenzel, Roswitha [Fachrichtung Chemie und Lebensmittelchemie, Technische Universitaet Dresden, Helmholtz Str. 10, D-01069 Dresden (Germany)] [Fachrichtung Chemie und Lebensmittelchemie, Technische Universitaet Dresden, Helmholtz Str. 10, D-01069 Dresden (Germany); Guth, Ulrich [Kurt-Schwabe-Institut fuer Mess- und Sensortechnik e. V. Meinsberg, Kurt-Schwabe-Str. 4, D-04720 Ziegra-Knobelsdorf (Germany)] [Kurt-Schwabe-Institut fuer Mess- und Sensortechnik e. V. Meinsberg, Kurt-Schwabe-Str. 4, D-04720 Ziegra-Knobelsdorf (Germany); Langbein, Hubert, E-mail: Hubert.Langbein@chemie.tu-dresden.de [Fachrichtung Chemie und Lebensmittelchemie, Technische Universitaet Dresden, Helmholtz Str. 10, D-01069 Dresden (Germany)] [Fachrichtung Chemie und Lebensmittelchemie, Technische Universitaet Dresden, Helmholtz Str. 10, D-01069 Dresden (Germany)

    2011-11-15T23:59:59.000Z

    Graphical abstract: Temperature dependent oxygen loss and uptake of V{sub 2,38}Nb{sub 10,7}O{sub 32,7} in N{sub 2} (p(O{sub 2}) = 4 x 10{sup -5} bar) and IR spectra of gas mixtures after the reactor with V{sub 2,38}Nb{sub 10,7}O{sub 32,7} (A = 16.1 m{sup 2}/g) and propane. Highlights: {yields} V{sub 2}O{sub 5}.xNb{sub 2}O{sub 5} complex oxide compounds as catalysts. {yields} The (V, Nb){sub 2}O{sub 5} phases are able to a reversible release and uptake of oxygen without a structural variation. {yields} Metastable (V, Nb){sub 2}O{sub 5} phases are able to catalyse the oxidative dehydrogenation of propane and propene. {yields} Thermodynamically stable VNb{sub 9}O{sub 25} phase shows no measurable catalytic activity. -- Abstract: In order to investigate the catalytic properties, V{sub 2,38}Nb{sub 10,7}O{sub 32,7}, VNb{sub 9}O{sub 25} and solid solutions of V{sub 2}O{sub 5} in TT-Nb{sub 2}O{sub 5} were prepared by thermal decomposition of freeze-dried oxalate precursors. The samples were characterised by X-ray diffraction and surface area determination. The crystalline samples are capable of the intercalation of sodium and lithium ions from solution. Above a temperature of about 500 {sup o}C, in dependence on the oxygen partial pressure a reversible release and uptake of oxygen without a structural variation takes place. The catalytic properties have been evaluated for the oxidative dehydrogenation (ODH) of propane and propene. There are only small differences in the catalytic activity of the different crystalline samples. Because of the relative high starting temperature, a selective catalytic oxidation of propane to propene is hardly observed.

  4. Interactions of Ba{sub 2}YCu{sub 3}O{sub 6+y} with the Gd{sub 3}NbO{sub 7} buffer layer in coated conductors

    SciTech Connect (OSTI)

    Wong-Ng, W., E-mail: Winnie.wong-ng@nist.go [Ceramics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Yang, Z. [Ceramics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Kaduk, J.A. [INEOS Technology, Naperville, IL 60566-7011 (United States); Cook, L.P. [Ceramics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Paranthaman, M. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2010-03-15T23:59:59.000Z

    A systematic study of the chemical interaction of Ba{sub 2}YCu{sub 3}O{sub 6+y} and Gd{sub 3}NbO{sub 7} was conducted under two processing conditions: purified air (21% p{sub o{sub 2}}), and 100 Pa p{sub o{sub 2}} (0.1% p{sub o{sub 2}}). Phases present along the pseudo-binary join Ba{sub 2}YCu{sub 3}O{sub 6z} and Gd{sub 3}NbO{sub 7} were found to be in two five-phase volumes within the BaO-1/2 Y{sub 2}O{sub 3}-1/2 Gd{sub 2}O{sub 3}-Nb{sub 2}O{sub 5}-CuO{sub y} system. Three common phases that are present in all samples are (Y,Gd){sub 2}Cu{sub 2}O{sub 5}, Ba(Y,Gd){sub 2}CuO{sub 5} and Cu{sub 2}O or CuO (depending on the processing conditions). The assemblies of phases can be categorized in three regions, with Ba{sub 2}YCu{sub 3}O{sub 6+y}: Gd{sub 3}NbO{sub 7} ratios of (I)<5.5:4.5; (II)=5.5:4.5; and (III)>5.5:4.5. The lowest melting temperature of the system was determined to be {approx}938 deg. C in air, and 850 deg. C at 100 Pa p{sub o{sub 2}}. Structure determinations of two selected phases, Ba{sub 2}(Gd{sub x}Y{sub 1-x})NbO{sub 6} (Fm3-barm, No. 225), and (Gd{sub x}Y{sub 3-x})NbO{sub 7} (C222{sub 1}, No. 20 and Ccmm, No. 63), were completed using the X-ray Rietveld refinement technique. Reference X-ray powder diffraction patterns for selected phases of Ba{sub 2}(Gd{sub x}Y{sub 1-x})NbO{sub 6} (x=0.2, 0.4, 0.6, and 0.8) and (Gd{sub x}Y{sub 3-x})NbO{sub 7} (x=0.6, 1.2, 1.8, 2.4 and 3) have been prepared for inclusion in the Powder Diffraction File (PDF). - Graphical abstract: Crystal structure for (Gd{sub x}Y{sub 3-x})NbO{sub 7} showing the partial layered feature. The alternate stacking of distorted NbO{sub 6} octahedra and (Gd,Y)O{sub 7} polyhedra are illustrated. The (Gd,Y)O{sub 8} polyhedra are omitted for clarity.

  5. Measurement and simulation of the cross sections for the production of {sup 148}Gd in thin {sup nat}W and {sup 181}Ta targets irradiated with 0.4- to 2.6-GeV protons

    SciTech Connect (OSTI)

    Titarenko, Yu. E., E-mail: Yury.Titarenko@itep.ru; Batyaev, V. F.; Titarenko, A. Yu.; Butko, M. A.; Pavlov, K. V.; Florya, S. N.; Tikhonov, R. S.; Zhivun, V. M. [Institute for Theoretical and Experimental Physics (Russian Federation); Ignatyuk, A. V. [Institute of Physics and Power Engineering (Russian Federation); Mashnik, S. G. [Los Alamos National Laboratory (United States); Leray, S.; Boudard, A. [CEA (France); Cugnon, J.; Mancusi, D. [University of Liege (Belgium); Yariv, Y. [SoreqNRC (Israel); Nishihara, K.; Matsuda, N. [JAEA (Japan); Kumawat, H. [BARC (India); Mank, G. [IAEA (Austria); Gudowski, W. [Royal Institute of Technology (Sweden)

    2011-04-15T23:59:59.000Z

    The cross sections for the production of {sup 148}Gd in {sup nat}W and {sup 181}Ta targets irradiated by 0.4-, 0.6-, 0.8-, 1.2-, 1.6-, and 2.6-GeV protons at the ITEP accelerator complex have been measured by direct {alpha} spectrometry without chemical separation. The experimental data have been compared with the data obtained at other laboratories and with the theoretical simulations of the yields on the basis of the BERTINI, ISABEL, CEM03.02, INCL4.2, INCL4.5, CASCADE07, and PHITS codes.

  6. Process for production of solution-derived (Pb,La)(Nb,Sn,Zr,Ti)O.sub.3 thin films and powders

    DOE Patents [OSTI]

    Boyle, Timothy J. (Albuquerque, NM)

    1999-01-01T23:59:59.000Z

    A simple and rapid process for synthesizing (Pb,La)(Nb,Sn,Zr,Ti)O.sub.3 precursor solutions and subsequent ferroelectric thin films and powders of the perovskite phase of these materials has been developed. This process offers advantages over standard methods, including: rapid solution synthesis (<10 minutes), use of commercially available materials, film production under ambient conditions, ease of lanthanum dissolution at high concentrations, and no heating requirements during solution synthesis. For lanthanum-doped ferroelectric materials, the lanthanum source can be added with total synthesis time less than 10 minutes. Films and powders are crystallized at approximately 650.degree. C. and exhibit ferroelectric properties comparable to films and powders produced by other techniques which require higher crystallization temperatures.

  7. STEM HAADF Image Simulation of the Orthorhombic M1 Phase in the Mo-V-Nb-Te-O Propane Oxidation Catalyst

    SciTech Connect (OSTI)

    D Blom; X Li; S Mitra; T Vogt; D Buttrey

    2011-12-31T23:59:59.000Z

    A full frozen phonon multislice simulation of high angle annular dark field scanning transmission electron microscopy (HAADF STEM) images from the M1 phase of the Mo-V-Nb-Te-O propane oxidation catalyst has been performed by using the latest structural model obtained using the Rietveld method. Simulated contrast results are compared with experimental HAADF images. Good agreement is observed at ring sites, however significant thickness dependence is noticed at the linking sites. The remaining discrepancies between the model based on Rietveld refinement and image simulations indicate that the sampling of a small volume element in HAADF STEM and averaging elemental contributions of a disordered site in a crystal slab by using the virtual crystal approximation might be problematic, especially if there is preferential Mo/V ordering near the (001) surface.

  8. The role of molybdenum additions and prior deformation on acicular ferrite formation in microalloyed Nb-Ti low-carbon line-pipe steels

    SciTech Connect (OSTI)

    Tang Zhenghua [Department of Materials Science and Metallurgical Engineering, University of Pretoria, Pretoria 0002 (South Africa)], E-mail: n22323784@yahoo.com; Stumpf, Waldo [Department of Materials Science and Metallurgical Engineering, University of Pretoria, Pretoria 0002 (South Africa)

    2008-06-15T23:59:59.000Z

    Microstructures in Nb-Ti-microalloyed line-pipe steels with various molybdenum additions, consisted mostly of acicular ferrite plus polygonal ferrite after hot rolling and rapid cooling. Structure-sensitive surface relief after etching on shadowed extraction replicas, allowed quantification of the acicular and polygonal ferrite contents. Continuous cooling transformation diagrams of two alloys, one Mo-free and the other containing 0.22% Mo, were determined for cooling rates from 0.1 to 40 deg. C s{sup -1} without and with prior deformation of the austenite below the nil-recrystallisation temperature. Molybdenum additions slightly enhanced the acicular ferrite formation in the strain-free austenite whereas prior deformation had a much greater effect, and strongly promoted acicular ferrite formation in both alloys. Thin foil electron microscopy of acicular ferrite in these low-inclusion content alloys showed a preference for parallel acicular ferrite laths with less 'chaotically' nucleated laths.

  9. Anomalous effect due to oxygen vacancy accumulation below the electrode in bipolar resistance switching Pt/Nb:SrTiO{sub 3} cells

    SciTech Connect (OSTI)

    Lee, Shinbuhm; Won Noh, Tae, E-mail: twnoh@snu.ac.kr [Center for Correlated Electron Systems, Institute for Basic Science, Seoul 151-747 (Korea, Republic of); Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of); Lee, Jae Sung [School of Physics, Korea Institute for Advanced Study, Seoul 130-722 (Korea, Republic of); Park, Jong-Bong; Koo Kyoung, Yong [Analytical Science Group, Samsung Advanced Institute of Technology, Yongin, Gyeonggi-do 446-712 (Korea, Republic of); Lee, Myoung-Jae [Logic TD, Semiconductor R and D Center, Samsung Electronics, Hwaseong-si, Gyeonggi-do 445-701 (Korea, Republic of)

    2014-06-01T23:59:59.000Z

    In conventional semiconductor theory, greater doping decreases the electronic resistance of a semiconductor. For the bipolar resistance switching (BRS) phenomena in oxides, the same doping principle has been used commonly to explain the relationship between the density variation of oxygen vacancies (V{sub o}¨) and the electronic resistance. We find that the V{sub o}¨ density can change at a depth of ?10 nm below the Pt electrodes in Pt/Nb:SrTiO{sub 3} cells, depending on the resistance state. Using electron energy loss spectroscopy and secondary ion mass spectrometry, we found that greater V{sub o}¨ density underneath the electrode resulted in higher resistance, contrary to the conventional doping principle of semiconductors. To explain this seemingly anomalous experimental behavior, we provide quantitative explanations on the anomalous BRS behavior by simulating the mobile V{sub o}¨ [J. S. Lee et al., Appl. Phys. Lett. 102, 253503 (2013)] near the Schottky barrier interface.

  10. Design and Analysis of TQS01, a 90 mm Nb3Sn Model Quadrupole for LHC Luminosity Upgrade Based on a Key and Bladder Assembly

    SciTech Connect (OSTI)

    Caspi, S.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bossert, R.C.; Dietderich, D.R.; Ferracin, P.; Ghosh, A.; Gourlay, S.A.; Hafalia, A.R.; Hannaford, C.R.; Kashikhin, V.S.; Kashikhin, V.V.; Lietzke, A.F.; Mattafirri, S.; McInturff, A.D.; Novitsky, I.V.; Sabbi, G.L.; Turrioni, D.; Yamada, R.; Zlobin, A.V.

    2006-06-01T23:59:59.000Z

    The US LHC Accelerator Research Program (LARP) is developing Nb{sub 3}Sn accelerator magnet technology for the LHC luminosity upgrade. Two 90 mm 'Technology Quadrupole' models (TQS01, TQC01) are being developed in close collaboration between LBNL and FNAL, using identical coil design, but two different support structures. The TQS01 structure was developed and tested at LBNL. With this approach coils are supported by an outer aluminum shell and assembled using keys and bladders. In contrast, the second model TQC01, utilize stainless steel collars and a thick stainless steel skin. This paper describes the TQS01 model magnet, its 3D ANSYS stress analysis, and anticipated instrumentation and assembly procedure.

  11. Process for production of solution-derived (Pb,La)(Nb,Sn,Zr,Ti)O{sub 3} thin films and powders

    DOE Patents [OSTI]

    Boyle, T.J.

    1999-01-12T23:59:59.000Z

    A simple and rapid process for synthesizing (Pb,La)(Nb,Sn,Zr,Ti)O{sub 3} precursor solutions and subsequent ferroelectric thin films and powders of the perovskite phase of these materials has been developed. This process offers advantages over standard methods, including: rapid solution synthesis (<10 minutes), use of commercially available materials, film production under ambient conditions, ease of lanthanum dissolution at high concentrations, and no heating requirements during solution synthesis. For lanthanum-doped ferroelectric materials, the lanthanum source can be added with total synthesis time less than 10 minutes. Films and powders are crystallized at approximately 650 C and exhibit ferroelectric properties comparable to films and powders produced by other techniques which require higher crystallization temperatures. 2 figs.

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

    SciTech Connect (OSTI)

    Kolodiazhnyi, T., E-mail: kolodiazhnyi.taras@nims.go.jp; Sakurai, H.; Vasylkiv, O.; Borodianska, H. [National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan); Mozharivskyj, Y. [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4M1 (Canada)

    2014-03-17T23:59:59.000Z

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

  13. The asteroseismological potential of the pulsating DB white dwarf stars CBS 114 and PG 1456+103

    E-Print Network [OSTI]

    Handler, G; Wood, M A

    2002-01-01T23:59:59.000Z

    We have acquired 65 h of single-site time-resolved CCD photometry of the pulsating DB white dwarf star CBS 114 and 62 h of two-site high-speed CCD photometry of another DBV, PG 1456+103. The pulsation spectrum of PG 1456+103 is complicated and variable on time scales of about one week and could only partly be deciphered with our measurements. The modes of CBS 114 are more stable in time and we were able to arrive at a frequency solution somewhat affected by aliasing, but still satisfactory, involving seven independent modes and two combination frequencies. These frequencies also explain the discovery data of the star, taken 13 years earlier. We find a mean period spacing of 37.1 +/- 0.7 s significant at the 98% level between the independent modes of CBS 114 and argue that they are due to nonradial g-mode pulsations of spherical degree l=1. We performed a global search for asteroseismological models of CBS 114 using a genetic algorithm, and we examined the susceptibility of the results to the uncertainties of ...

  14. PERIODIC VARIATIONS IN THE O - C DIAGRAMS OF FIVE PULSATION FREQUENCIES OF THE DB WHITE DWARF EC 20058-5234

    SciTech Connect (OSTI)

    Dalessio, J.; Provencal, J. L.; Shipman, H. L. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States)] [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Sullivan, D. J.; Sullivan, T. [School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6012 (New Zealand)] [School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6012 (New Zealand); Kilkenny, D. [Department of Physics, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa)] [Department of Physics, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Fraga, L. [Southern Observatory for Astrophysical Research, Casilla 603, La Serena (Chile)] [Southern Observatory for Astrophysical Research, Casilla 603, La Serena (Chile); Sefako, R. [South African Astronomical Observatory, P.O. Box 9, Observatory 7935 (South Africa)] [South African Astronomical Observatory, P.O. Box 9, Observatory 7935 (South Africa)

    2013-03-01T23:59:59.000Z

    Variations in the pulsation arrival time of five independent pulsation frequencies of the DB white dwarf EC 20058-5234 individually imitate the effects of reflex motion induced by a planet or companion but are inconsistent when considered in unison. The pulsation frequencies vary periodically in a 12.9 year cycle and undergo secular changes that are inconsistent with simple neutrino plus photon-cooling models. The magnitude of the periodic and secular variations increases with the period of the pulsations, possibly hinting that the corresponding physical mechanism is located near the surface of the star. The phase of the periodic variations appears coupled to the sign of the secular variations. The standards for pulsation-timing-based detection of planetary companions around pulsating white dwarfs, and possibly other variables such as subdwarf B stars, should be re-evaluated. The physical mechanism responsible for this surprising result may involve a redistribution of angular momentum or a magnetic cycle. Additionally, variations in a supposed combination frequency are shown to match the sum of the variations of the parent frequencies to remarkable precision, an expected but unprecedented confirmation of theoretical predictions.

  15. A 3-Stage Shunt-Feedback Op-Amp having 19.2dB Gain, 54.1dBm OIP3 (2GHz), and 252 OIP3/PDC ratio

    E-Print Network [OSTI]

    Rodwell, Mark J. W.

    A 3-Stage Shunt-Feedback Op-Amp having 19.2dB Gain, 54.1dBm OIP3 (2GHz), and 252 OIP3/PDC ratio-Miller compensation demon- strating 19.2dB mid-band S21 gain, PDC = 1020mW. At 2GHz operation the amplifier shows 54.1dBm OIP3 and a record high OIP3/PDC ratio = 252. Through the use of a 350GHz f , fmax 0.5um InP HBT

  16. JOURNAL DE PHYSIQUE Colloque C6, supplment au n 12, Tome 37, Dcembre 1976, page C6-117 MOSSBAUER SPECTROSCOPY OF Fe IMPURITIES IN LiNb03

    E-Print Network [OSTI]

    Boyer, Edmond

    JOURNAL DE PHYSIQUE Colloque C6, supplément au n° 12, Tome 37, Décembre 1976, page C6-117 MOSSBAUER. -- The Mossbauer effect of dilute Fe3+ and Fe2+ ions in LiNbo3 single crystals is reported. For Fe3+ typical-axis. Previous Mossbauer results [4] obtained with LiNb03 single crystals Fe57 -doped by diffusion indi- cated

  17. Guided wave propagation in 0.67Pb,,Mg1/3Nb2/3...O30.33PbTiO3 single crystal plate poled along 001c

    E-Print Network [OSTI]

    Cao, Wenwu

    Guided wave propagation in 0.67Pb,,Mg1/3Nb2/3...O3­0.33PbTiO3 single crystal plate poled along 001c relations of Lamb waves and shear horizontal SH waves propagating in the 100 and 110 directions of 0.67Pb Mg, respectively, for waves propagating along 100 and 110 directions. These limiting velocities

  18. A-site deficient perovskites in the SrO-ZrO{sub 2}-Nb{sub 2}O{sub 5} system: Composition dependent structures from neutron powder diffraction data

    SciTech Connect (OSTI)

    Schmid, Siegbert, E-mail: S.Schmid@chem.usyd.edu.au [School of Chemistry, University of Sydney, Sydney NSW 2006 (Australia); Withers, Ray L. [Research School of Chemistry, Australian National University, Canberra ACT 0200 (Australia)

    2012-07-15T23:59:59.000Z

    A series of A-site deficient perovskite-type phases was synthesised and characterised in the SrO-ZrO{sub 2}-Nb{sub 2}O{sub 5} system. The composition range was established as Sr{sub 0.70+x}Zr{sub 0.40+2x}Nb{sub 0.60-2x}O{sub 3}, {approx}0.02{<=}x{<=}0.30, and the resulting structures refined using high resolution neutron powder diffraction data. While structures in this composition range are closely related to the cubic perovskite parent, the symmetry for all investigated compositions is lowered to tetragonal or orthorhombic. For x<0.15 the resulting space group is tetragonal I4/mcm, for x>0.15 it is orthorhombic Pnma and for x=0.15 two phases co-exist, in space groups I4/mcm and Pnma. - Graphical abstract: Structured diffuse intensity indicating additional short range order in the defect perovskite Sr{sub 0.72}Zr{sub 0.44}Nb{sub 0.56}O{sub 3}. Highlights: Black-Right-Pointing-Pointer A-site deficient perovskites synthesised in Sr{sub 0.70+x}Zr{sub 0.40+2x}Nb{sub 0.60-2x}O{sub 3}, {approx}0.02 {<=}x{<=}0.30. Black-Right-Pointing-Pointer Space groups established from X-ray, electron and neutron powder diffraction. Black-Right-Pointing-Pointer Structures refined and phase transition established from neutron diffraction data.

  19. First-principle calculation and assignment for vibrational spectra of Ba(Mg{sub 1/3}Nb{sub 2/3})O{sub 3} microwave dielectric ceramic

    SciTech Connect (OSTI)

    Diao, Chuan-Ling [College of Physics and Electronics, Shandong Normal University, Jinan 250014 (China); State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Wang, Chun-Hai; Lu, Jing [State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China); Luo, Neng-Neng; Jing, Xi-Ping, E-mail: sf751106@sina.com.cn, E-mail: xpjing@pku.edu.cn [State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Qi, Ze-Ming; Shao, Tao; Wang, Yu-Yin [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China); Wang, Quan-Chao; Kuang, Xiao-Jun; Fang, Liang [MOE Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, College of Materials Science and Engineering, Guilin University of Technology, Guilin 541004 (China); Shi, Feng, E-mail: sf751106@sina.com.cn, E-mail: xpjing@pku.edu.cn [College of Physics and Electronics, Shandong Normal University, Jinan 250014 (China)

    2014-03-21T23:59:59.000Z

    1:2 B-site cation ordered Ba(Mg{sub 1/3}Nb{sub 2/3})O{sub 3} ceramic was synthesized using conventional solid-state reaction at 1600?°C for 12?h. The structure parameters were obtained through Rietveld refinement of X-ray diffraction data. The Raman peak frequencies were obtained by Lorenz fitting on Raman spectrum. Four-parameter semiquantum model was used to fit the infrared (IR) reflectivity spectrum, and the fitted parameters were used to calculate the dielectric permittivity ? and dielectric loss tan?. A total of 9 active Raman and 16 active IR modes were obtained using first-principle calculations based on density functional theory with local density approximation. All of the vibrational modes were assigned and represented by linear combinations of the symmetry coordinates deduced using group theory analysis. The Raman mode with the highest frequency A{sub 1g}{sup (4)} (789?cm{sup ?1}) can be described as the breathing vibration of NbO{sub 6}. The IR modes E{sub u}{sup (1)} (149?cm{sup ?1}) and A{sub 2u}{sup (2)} (212?cm{sup ?1}), which can be described as the twisting vibrations of Ba–MgO{sub 6}/Ba–NbO{sub 6} on the a–b plane and the stretching vibrations of Ba–MgO{sub 6}/Ba–NbO{sub 6} along the c direction, respectively, are the dominant contributing modes to ? and tan?. The dielectric property parameters obtained using IR spectrum fittings, first-principal calculations, and microwave measurements were compared.

  20. Effect of tungsten doping in bismuth-layered Na{sub 0.5}Bi{sub 2.5}Nb{sub 2}O{sub 9} high temperature piezoceramics

    SciTech Connect (OSTI)

    Zhou, Zhiyong, E-mail: zyzhou@mail.sic.ac.cn; Li, Yuchen; Hui, Shipeng; Dong, Xianlin [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)] [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)

    2014-01-06T23:59:59.000Z

    The effects of W{sup 6+} doping for B site on the structural and electrical properties of Na{sub 0.5}Bi{sub 2.5}Nb{sub 2}O{sub 9}-based ceramics were studied. It shows a trend of preferable orientation growth along c-axis and the Curie point (T{sub c}) decreases slightly from 792 to 761?°C with the increasing W{sup 6+} amount. The electrical resistivity of Na{sub 0.5}Bi{sub 2.5}Nb{sub 2}O{sub 9}-based ceramics increases as much as about two orders of magnitude and the piezoelectric constant d{sub 33} is significantly improved from 10.5 to 21.8 pC/N by W{sup 6+} modification. The composition of Na{sub 0.5}Bi{sub 2.5}Nb{sub 1.99}W{sub 0.01}O{sub 9} with a high T{sub c} (792?°C), very good temperature stability up to ?0.96T{sub c}, a large d{sub 33} of 17.9 pC/N and sufficient high resistivity, is an excellent candidate for high temperature piezoelectric applications.

  1. Uncoupling at the GABA(A) receptor with chronic ethanol in the rat medial septum/diagonal band (MS/DB)

    E-Print Network [OSTI]

    Wallace, Kathleen Allison

    1997-01-01T23:59:59.000Z

    101 g 133 ml 132 ml 4ml 40 ml 20 ml 20 ml *To make 6 and 7 % w/v ethanol liquid diet, mix 35 ml of ethanol liquid diet plus 15 ml of control liquid diet and 40 ml of ethanol liquid diet plus 10 ml of control liquid diet, respectively, for a...-rapid drug application onto an acutely dissociated MS/DB neuron in a patch clamp configuration. The barrel (bath) is shown closest to cell. The barrel (drug) just above the cell contains bath plus appropriate concentration of drug. Thus, rapid drug...

  2. X-ray diffraction on the X-cut of a Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} single crystal modulated by a surface acoustic wave

    SciTech Connect (OSTI)

    Irzhak, D., E-mail: irzhak@iptm.ru; Roshchupkin, D., E-mail: rochtch@iptm.ru [Institute of Microelectronics Technology and High-Purity Materials Russian Academy of Sciences, Chernogolovka 142432 (Russian Federation)

    2014-06-28T23:59:59.000Z

    The result of X-ray diffraction study on a single crystal of the calcium-gallogermanate family Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} (CTGS) modulated by a surface acoustic wave (SAW) is presented. The power flow angle for SAW propagating along the X{sub 2} axis of the X-cut in CTGS was measured. The rocking curves for the CTGS crystal were recorded at different amplitudes of an input high frequency electric signal on interdigital transducer used to excite a SAW. Based on the data obtained, intensity dependence of diffraction satellites on the amplitude of electric signal exciting a SAW was built. Numerical simulation of the crystal rocking curves and dependence of diffraction satellite intensities on the SAW amplitude enabled the selection of a set of material constants at which the most complete coincidence of experimental and calculated results is observed.

  3. Measurement and simulation of the cross sections for nuclide production in {sup nat}W and {sup 181}Ta targets irradiated with 0.04- to 2.6-GeV protons

    SciTech Connect (OSTI)

    Titarenko, Yu. E., E-mail: Yury.Titarenko@itep.ru; Batyaev, V. F.; Titarenko, A. Yu.; Butko, M. A.; Pavlov, K. V.; Florya, S. N.; Tikhonov, R. S.; Zhivun, V. M. [Institute for Theoretical and Experimental Physics (Russian Federation); Ignatyuk, A. V. [Institute of Physics and Power Engineering (Russian Federation); Mashnik, S. G. [Los Alamos National Laboratory (United States); Leray, S.; Boudard, A. [CEA (France); Cugnon, J.; Mancusi, D. [University of Liege (Belgium); Yariv, Y. [SoreqNRC (Israel); Nishihara, K.; Matsuda, N. [JAEA (Japan); Kumawat, H. [BARC (India); Mank, G. [IAEA (Austria); Gudowski, W. [Royal Institute of Technology (Sweden)

    2011-04-15T23:59:59.000Z

    The cross sections for nuclide production in thin {sup nat}Wand {sup 181}Ta targets irradiated by 0.04-2.6-GeV protons have been measured by direct {gamma} spectrometry using two {gamma} spectrometers with the resolutions of 1.8 and 1.7 keV in the {sup 60}Co 1332-keV {gamma} line. As a result, 1895 yields of radioactive residual product nuclei have been obtained. The {sup 27}Al(p, x){sup 22}Na reaction has been used as a monitor reaction. The experimental data have been compared with the MCNPX (BERTINI, ISABEL), CEM03.02, INCL4.2, INCL4.5, PHITS, and CASCADE07 calculations.

  4. The asteroseismological potential of the pulsating DB white dwarf stars CBS 114 and PG 1456+103

    E-Print Network [OSTI]

    G. Handler; T. S. Metcalfe; M. A. Wood

    2002-05-27T23:59:59.000Z

    We have acquired 65 h of single-site time-resolved CCD photometry of the pulsating DB white dwarf star CBS 114 and 62 h of two-site high-speed CCD photometry of another DBV, PG 1456+103. The pulsation spectrum of PG 1456+103 is complicated and variable on time scales of about one week and could only partly be deciphered with our measurements. The modes of CBS 114 are more stable in time and we were able to arrive at a frequency solution somewhat affected by aliasing, but still satisfactory, involving seven independent modes and two combination frequencies. These frequencies also explain the discovery data of the star, taken 13 years earlier. We find a mean period spacing of 37.1 +/- 0.7 s significant at the 98% level between the independent modes of CBS 114 and argue that they are due to nonradial g-mode pulsations of spherical degree l=1. We performed a global search for asteroseismological models of CBS 114 using a genetic algorithm, and we examined the susceptibility of the results to the uncertainties of the observational frequency determinations and mode identifications (we could not provide m values). The families of possible solutions are identified correctly even without knowledge of m. Our optimal model suggests Teff = 21,000 K and M_* = 0.730 M_sun as well as log(M_He/M_*) = -6.66, X_O = 0.61. This measurement of the central oxygen mass fraction implies a rate for the ^12C(alpha,gamma)^16O nuclear reaction near S_300=180 keV b, consistent with laboratory measurements.

  5. Synthesis and characterisation of the novel double perovskites La{sub 2}CrB{sub 2/3}Nb{sub 1/3}O{sub 6}, B = Mg, Ni, Cu

    SciTech Connect (OSTI)

    Svensson, G., E-mail: gunnar.svensson@mmk.su.se [Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm (Sweden); Grins, J.; Shafeie, S.; Masson, D. [Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm (Sweden)] [Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm (Sweden); Norberg, S.T.; Eriksson, S. [Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden)] [Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden); Hull, S. [ISIS, Rutherford Appleton Laboratory, Didcot OX11 OQX (United Kingdom)] [ISIS, Rutherford Appleton Laboratory, Didcot OX11 OQX (United Kingdom); Zakharov, K.V.; Volkova, O.S.; Vasil’ev, A.N.; Istomin, S.Ya. [M.V. Lomonosov Moscow State University, 119991 Moscow (Russian Federation)] [M.V. Lomonosov Moscow State University, 119991 Moscow (Russian Federation)

    2012-09-15T23:59:59.000Z

    Highlights: ? La{sub 2}CrB{sub 2/3}Nb{sub 1/3}O{sub 6}, B = Mg, Ni, Cu perovskites adopt the GdFeO{sub 3} type structure. ? HREM and ED study indicating week ordering of B-cations for B = Mg. ? Antiferromagnetics with T{sub N} 90 (Mg), 125 (Ni) and 140 K (Ni). -- Abstract: The novel perovskites La{sub 2}CrB{sub 2/3}Nb{sub 1/3}O{sub 6}, B = Mg, Ni, and Cu have been synthesised at 1350 °C in air via the citrate route. Rietveld refinements using neutron powder diffraction (NPD) data showed that the compounds adopt the GdFeO{sub 3} type structure with space group Pbnm, and unit cell parameters a?b??(2)×a{sub p} and c ? 2 × a{sub p}, where a{sub p} ? 3.8 ?. Selected area electron diffraction (SAED) of B = Ni and Cu samples confirmed space group Pbnm. However, distinct reflections forbidden in Pbnm symmetry, but allowed in the monoclinic sub-group P2{sub 1}/n and unit cell parameters a?b??(2)×a{sub p} and c ? 2 × a{sub p}, ? ? 90° were present in SAED patterns of B = Mg sample. This indicates an ordering of the B-cations within the crystal structure of La{sub 2}CrMg{sub 2/3}Nb{sub 1/3}O{sub 6}. High-resolution electron microscopy (HREM) study indicating uniform, without formation of clusters, ordering of B-cations in the crystallites of La{sub 2}CrMg{sub 2/3}Nb{sub 1/3}O{sub 6}. Magnetic susceptibility measurements show that the compounds are antiferromagnetic (with some glass or spin clustering effects due to additional ferromagnetic interactions between the B-cations) with T{sub N} for La{sub 2}CrB{sub 2/3}Nb{sub 1/3}O{sub 6}, B = Mg, Ni, Cu being 90, 125 and 140 K, respectively.

  6. Single phase synthesis and room temperature neutron diffraction studies on multiferroic PbFe{sub 0.5}Nb{sub 0.5}O{sub 3}

    SciTech Connect (OSTI)

    Matteppanavar, Shidaling; Angadi, Basavaraj [Department of Physics, JB Campus, Bangalore University, Bangalore -560056 (India); Rayaprol, Sudhindra [UGC-DAE-CSR, Mumbai Centre, BARC, Mumbai - 400085 (India)

    2013-02-05T23:59:59.000Z

    The lead-iron-niobate, (PbFe{sub 0.5}Nb{sub 0.5}O{sub 3} or PFN) was synthesized by low temperature sintering Single Step / Solid State Reaction Method. The 700 Degree-Sign C/2 hrs. calcined powder was sintered at 1050 Degree-Sign C/1 hr. The sintered pellets were characterized through X-Ray Diffraction and Neutron Diffraction at room temperature. It is found from the XRD pattern that the materials is in single phase with no traces of pyrochlore phase. It was also confirmed from the neutron diffraction pattern, the structure of PFN to be monoclinic, space group Cm. Structural studies has been carried out by refining the obtained neutron diffraction data by Rietveld refinement method using Fullprof program. The neutron diffraction pattern at 300 K (room temperature) was selected to refine the structure. The lattice parameters obtained are; a = 5.6709 A, b = 5.6732 A, c = 4.0136 A, and {alpha}= 90, {beta}= 89.881, {gamma}= 90. The P-E measurements showed hysteretic behavior with high remnant polarization.

  7. Adsorption of propane, isopropyl, and hydrogen on cluster models of the M1 phase of Mo-V-Te-Nb-O mixed metal oxide catalyst

    SciTech Connect (OSTI)

    Govindasamy, Agalya [University of Cincinnati; Muthukumar, Kaliappan [University of Cincinnati; Yu, Junjun [University of Cincinnati; Xu, Ye [ORNL; Guliants, Vadim V. [University of Cincinnati

    2010-01-01T23:59:59.000Z

    The Mo-V-Te-Nb-O mixed metal oxide catalyst possessing the M1 phase structure is uniquely capable of directly converting propane into acrylonitrile. However, the mechanism of this complex eight-electron transformation, which includes a series of oxidative H-abstraction and N-insertion steps, remains poorly understood. We have conducted a density functional theory study of cluster models of the proposed active and selective site for propane ammoxidation, including the adsorption of propane, isopropyl (CH{sub 3}CHCH{sub 3}), and H which are involved in the first step of this transformation, that is, the methylene C-H bond scission in propane, on these active site models. Among the surface oxygen species, the telluryl oxo (Te=O) is found to be the most nucleophilic. Whereas the adsorption of propane is weak regardless of the MO{sub x} species involved, isopropyl and H adsorption exhibits strong preference in the order of Te=O > V=O > bridging oxygens > empty Mo apical site, suggesting the importance of TeO{sub x} species for H abstraction. The adsorption energies of isopropyl and H and consequently the reaction energy of the initial dehydrogenation of propane are strongly dependent on the number of ab planes included in the cluster, which points to the need to employ multilayer cluster models to correctly capture the energetics of surface chemistry on this mixed metal oxide catalyst.

  8. On the nature of phase transitions in the tetragonal tungsten bronze GdK{sub 2}Nb{sub 5}O{sub 15} ceramics

    SciTech Connect (OSTI)

    Gagou, Y.; Lukyanchuk, I.; El Marssi, M., E-mail: mimoun.elmarssi@u-picardie.fr [Laboratoire de Physique de la Matičre Condensée, Université de Picardie Jules Verne, 33 rue Saint-Leu, 80039 Amiens Cedex (France); Amira, Y. [Laboratoire de Physique de la Matičre Condensée, Université de Picardie Jules Verne, 33 rue Saint-Leu, 80039 Amiens Cedex (France); Laboratoire de la Matičre Condensée et Nanostructures, FSTG, Université Cadi Ayyad Marrakech, Maroc (Morocco); Mezzane, D. [Laboratoire de la Matičre Condensée et Nanostructures, FSTG, Université Cadi Ayyad Marrakech, Maroc (Morocco); Courty, M.; Masquelier, C. [Laboratoire de Réactivité et Chimie des Solides, UMR 7314, Université de Picardie Jules Verne, Pôle Scientifique, 33 rue Saint-Leu, 80039 Amiens Cedex 1 (France); Yuzyuk, Yu. I. [Faculty of Physics, Southern Federal University, 5, Zorge Str. Rostov-on-Don 344090 (Russian Federation)

    2014-02-14T23:59:59.000Z

    Phase transitions in gadolinium potassium niobate GdK{sub 2}Nb{sub 5}O{sub 15} (GKN) ceramics have been investigated by x-ray diffraction, dielectric susceptibility, differential scanning calorimetry, and Raman scattering. The results of our complementary studies show that GKN exhibits two phase transitions at T{sub c1}?=?238?°C and T{sub c2}?=?375?°C attributed to the ferroelectric-antiferroelectric-paraelectric (FE-AFE-PE) phase transitions. According to the x-ray diffraction analysis, the FE and PE phases were refined in the polar P4bm and centrosymmetric P4/mbm space groups. For the intermediate phase, the structure is refined in the space group P4nc with doubling of the c unit cell parameter, which is compatible with an AFE phase. This result was confirmed by Raman spectroscopy since new low-frequency lines are activated in the AFE phase due to the Brillouin zone-folding effect, typical for the modulated phases. The presence of the AFE phase between the FE and PE phases and the complex nature of tetragonal tungsten bronze crystal structure can explain the large thermal hysteresis observed at the FE-AFE transition between heating and cooling cycle and the strong depression of the Curie-Weiss temperature T{sub 0}. The semi-phenomenological Ising-like model based on the obtained experimental data is proposed to account for the observed FE-AFE-PE transition sequence.

  9. Pressure dependence of the monoclinic phase in (1–x)Pb(Mg1/3Nb2/3)O3-xPbTiO? solid solutions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

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

    2012-12-01T23:59:59.000Z

    We combine high-pressure x-ray diffraction, high-pressure Raman scattering, and optical microscopy to investigate a series of (1–x)Pb(Mg1/3Nb2/3)O3-xPbTiO? (PMN-xPT) solid solutions (x=0.2, 0.3, 0.33, 0.35, 0.37, 0.4) in diamond anvil cells up to 20 GPa at 300 K. The Raman spectra show a peak centered at 380 cm?ą starting above 6 GPa for all samples, in agreement with previous observations. X-ray diffraction measurements are consistent with this spectral change indicating a structural phase transition; we find that the triplet at the pseudocubic (220) Bragg peak merges into a doublet above 6 GPa. Our results indicate that the morphotropic phase boundary region (x=0.33–0.37) with the presence of monoclinic symmetry persists up to 7 GPa. The pressure dependence of ferroelectric domains in PMN-0.32PT single crystals was observed using a polarizing optical microscope. The domain wall density decreases with pressure and the domains disappear at a modest pressure of 3 GPa. We propose a pressure-composition phase diagram for PMN-xPT solid solutions.

  10. Energy levels, oscillator strengths, radiative decay rates, and fine-structure collision strengths for the Zn-like ions Nb XII and Mo XIII

    SciTech Connect (OSTI)

    Liang, Liang, E-mail: liangll501@163.com; Liu, Xu-yang; Zhou, Chao

    2014-07-15T23:59:59.000Z

    Energy levels, line strengths, oscillator strengths, radiative decay rates, and fine-structure collision strengths are presented for the Zn-like ions Nb XII and Mo XIII. The atomic data are calculated with the AUTOSTRUCTURE code, where relativistic corrections are introduced according to the Breit–Pauli distorted wave approach. We present the calculations of atomic data for 110 fine-structure levels generated from fifteen configurations (1s{sup 2}2s{sup 2}2p{sup 6}3s{sup 2}3p{sup 6}3d{sup 10})4s{sup 2}, 4s4p, 4p{sup 2}, 4s4d, 4s4f, 4s5s, 4p4d, 4s5p, 4s5d, 4p4f, 4p5s, 4d{sup 2}, 4d4f, 4f{sup 2}, and 3d{sup 9}4s{sup 2}4p. Fine-structure collision strengths for transitions from the ground and the first four excited levels are presented at six electron energies (20, 50, 80, 110, 150, and 180 Ryd). Our atomic structure data are compared with the available experimental and theoretical results.

  11. Pressure dependence of the monoclinic phase in (1–x)Pb(Mg1/3Nb2/3)O3-xPbTiO? solid solutions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

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

    2012-12-01T23:59:59.000Z

    We combine high-pressure x-ray diffraction, high-pressure Raman scattering, and optical microscopy to investigate a series of (1–x)Pb(Mg1/3Nb2/3)O3-xPbTiO? (PMN-xPT) solid solutions (x=0.2, 0.3, 0.33, 0.35, 0.37, 0.4) in diamond anvil cells up to 20 GPa at 300 K. The Raman spectra show a peak centered at 380 cm?ą starting above 6 GPa for all samples, in agreement with previous observations. X-ray diffraction measurements are consistent with this spectral change indicating a structural phase transition; we find that the triplet at the pseudocubic (220) Bragg peak merges into a doublet above 6 GPa. Our results indicate that the morphotropic phase boundary regionmore »(x=0.33–0.37) with the presence of monoclinic symmetry persists up to 7 GPa. The pressure dependence of ferroelectric domains in PMN-0.32PT single crystals was observed using a polarizing optical microscope. The domain wall density decreases with pressure and the domains disappear at a modest pressure of 3 GPa. We propose a pressure-composition phase diagram for PMN-xPT solid solutions.« less

  12. Development and Application of a ReaxFF Reactive Force Field for Oxidative Dehydrogenation on Vanadium Oxide Catalysts

    E-Print Network [OSTI]

    Goddard III, William A.

    oxidize or ammoxidize pro- pane, with the most promising MMO catalysts containing Mo, V, Te, Ta, and Nb.3 pertinent to this paper is the use of QM to elucidate the mechanism for propane ODH using QM

  13. Trace elements in magnetite as petrogenetic indicators Sarah A. S. Dare & Sarah-Jane Barnes & Georges Beaudoin &

    E-Print Network [OSTI]

    , Zr, Nb, Mo, Sn, Hf, Ta, W, and Pb), using laser ablation ICP-MS and electron microprobe, from hydrothermal deposits where laser mapping reveals oscillato- ry zoning, which records the changing conditions

  14. Clamping-induced changes of domain morphology in 88%Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}-12%PbTiO{sub 3}

    SciTech Connect (OSTI)

    Chang, L.-W., E-mail: lchang01@qub.ac.uk; Gregg, J. M., E-mail: m.gregg@qub.ac.uk [Centre for Nanostructured Media, School of Maths and Physics, Queen's University Belfast, Northern Ireland BT7 1NN (United Kingdom); Nagarajan, V.; Okatan, M. B. [School of Materials Science and Engineering, University of New South Wales, New South Wales 2052 (Australia)

    2014-08-14T23:59:59.000Z

    Domain microstructures in single crystal lamellae of 88%Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}-12%PbTiO{sub 3} (cut from bulk using focused ion beam milling) have been mapped using both piezoresponse force microscopy and transmission electron microscopy. Dramatic changes from mottled microstructures typical of relaxors to larger scale domains typical of ferroelectrics have been noted. Stresses associated with substrate clamping are suspected as the cause for the transition from short- to long-range polar order, akin to effects induced by cation ordering achieved by thermal quenching.

  15. Crystal growth and characterization of tungsten-bronze ferroelectric Pb-K-niobate, Pb(1-x)K(2x)Nb(2)O(6), with x = 0.23

    E-Print Network [OSTI]

    Jana, Pradeep

    1993-01-01T23:59:59.000Z

    ol thc rcrlutrcmcnts foi thc dcgrcc ol' MASTER OF SCIFNCE August 1993 Major Subject: Electrical Engineering w z ~+~~~' / p i ~%M 4, Crystal Growth and Characterization of Tungsten-Bronze Ferroelectric Pb-K-Wiobate, Pbt ?Kz?NbzO&, with x = 0. 23...&vth and Characicnzat&on ol Tungsten-Bronze Ferroclcctiic Pb-K-Niobaic, Pbi ?K2?NbzO&& w?h s = 0. 23 (Augus& 1993) Pradccp Jana, H. E. , Bangalo&c Unix crsitv Chair ol Ad& isory Committcc: Dr. R. K. Pandc) Lead-potass&uum-niobatc Pb& ?K2?Nb20o (PKN) is a mcmbcr ol...

  16. Room temperature in-plane ?100? magnetic easy axis for Fe{sub 3}O{sub 4}/SrTiO{sub 3}(001):Nb grown by infrared pulsed laser deposition

    SciTech Connect (OSTI)

    Monti, Matteo; Sanz, Mikel; Oujja, Mohamed; Rebollar, Esther; Castillejo, Marta; Marco, José F.; Figuera, Juan de la, E-mail: juan.delafiguera@iqfr.csic.es [Instituto de Química Física “Rocasolano,” CSIC, Madrid E-28006 (Spain); Pedrosa, Francisco J.; Bollero, Alberto [IMDEA Nanociencia, Instituto Madrileńo de Estudios Avanzados en Nanociencia, Madrid E-28049 (Spain); Camarero, Julio; Cuńado, Jose Luis F. [IMDEA Nanociencia, Instituto Madrileńo de Estudios Avanzados en Nanociencia, Madrid E-28049 (Spain); Dpto. de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid E-28049 (Spain); Nemes, Norbert M. [Dpto. de Física Aplicada III, Universidad Complutense de Madrid, Madrid E-28040 (Spain); Mompean, Federico J.; Garcia-Hernández, Mar [Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid E-28049 (Spain); Nie, Shu; McCarty, Kevin F. [Sandia National Laboratories, Livermore, California 94550 (United States); N'Diaye, Alpha T.; Chen, Gong; Schmid, Andreas K. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2013-12-14T23:59:59.000Z

    We examine the magnetic easy-axis directions of stoichiometric magnetite films grown on SrTiO{sub 3}:Nb by infrared pulsed-laser deposition. Spin-polarized low-energy electron microscopy reveals that the individual magnetic domains are magnetized along the in-plane ?100? film directions. Magneto-optical Kerr effect measurements show that the maxima of the remanence and coercivity are also along in-plane ?100? film directions. This easy-axis orientation differs from bulk magnetite and films prepared by other techniques, establishing that the magnetic anisotropy can be tuned by film growth.

  17. MAE TEACHING ASSISTANT / READER ASSIGNMENTS 1/7/13 12:12 COURSE INSTRUCTOR TA_name1 TA1 TA_name2 TA2 TA_name3 TA3 TA_name4 TA4 TA_name5 TA5 TAtotal

    E-Print Network [OSTI]

    Mease, Kenneth D.

    , Alex 1.00 Borrajo, Rafael 0.50 1.50 MAE110 McDonell McLarty, Dustin 0.50 0.50 MAE115 Brouwer Jarrahbashi, Dorrin 1.00 Fardadi, Mahshid 0.50 Taghavi, Shervin 0.50 2.00 MAE130A Papamoschou Hernandez, Franz.50 MAE130B LaRue Hernandez, Franz 1.00 Koster, Timothy 0.50 1.50 MAE146 Villac Nakhjiri, Navid 0.50 0

  18. ZipperDB: Predictions of Fibril-forming Segments within Proteins Identified by the 3D Profile Method (from the UCLA-DOE Institute for Genomics and Proteomics)

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

    Goldschmidt, L.; Teng, P. K.; Riek, R.; Eisenberg, D.

    ZipperDB contains predictions of fibril-forming segments within proteins identified by the 3D Profile Method. The UCLA-DOE Institute for Genomics and Proteomics has analyzed over 20,000 putative protein sequences for segments with high fibrillation propensity that could form a "steric zipper"ůtwo self-complementary beta sheets, giving rise to the spine of an amyloid fibril. The approach is unique in that structural information is used to evaluate the likelihood that a particular sequence can form fibrils. [copied with edits from http://www.doe-mbi.ucla.edu/]. In addition to searching the database, academic and non-profit users may also submit their protein sequences to the database.

  19. Characterization of timing jitter spectra in free-running mode-locked lasers with 340 dB dynamic range over 10 decades of Fourier frequency

    E-Print Network [OSTI]

    Jung, Kwangyun

    2014-01-01T23:59:59.000Z

    We demonstrate a method that enables accurate timing jitter spectral density characterization of free-running mode-locked laser oscillators over more than 10-decade of Fourier frequency from mHz to tens MHz range. The method is based on analyzing both the input voltage noise to the slave laser and the output voltage noise from the balanced optical cross- correlator (BOC), when two mode-locked lasers are synchronized in repetition rate by the BOC. As a demonstration experiment, timing jitter spectrum of a free-running mode-locked Er-fiber laser with a dynamic range of >340 dB is measured over Fourier frequency ranging from 1 mHz to 38.5 MHz (Nyquist frequency). The demonstrated method can resolve different noise mechanisms that cause specific jitter characteristics in free-running mode-locked laser oscillators for a vast range of time scales from 1000-s.

  20. Enhanced ferroelectric and dielectric properties of (111)-oriented highly cation-ordered PbSc{sub 0.5}Ta{sub 0.5}O{sub 3} thin films

    SciTech Connect (OSTI)

    Chopra, Anuj [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Saale) (Germany); Faculty of Science and Technology, MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Birajdar, Balaji I. [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Saale) (Germany); Special Centre for Nano Sciences, Jawaharlal Nehru University, New Delhi 110067 (India); Kim, Yunseok [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Saale) (Germany); School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon 440-746 (Korea, Republic of); Alexe, Marin [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Saale) (Germany); Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Hesse, Dietrich [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Saale) (Germany)

    2013-12-14T23:59:59.000Z

    Cation-ordered (111)-oriented epitaxial PbSc{sub 0.5}Ta{sub 0.5}O{sub 3} (PST) thin films were deposited by pulsed laser deposition on SrRuO{sub 3}-electroded SrTiO{sub 3} (111) substrates at three different temperatures of 525?°C, 550?°C, and 575?°C. All the films were well crystalline and (111)-oriented at all the three growth temperatures; however, the films deposited at the temperatures other than 550?°C exhibited the presence of a pyrochlore phase. X-ray diffraction analysis and transmission electron microscopy measurements revealed that the films were epitaxial and highly cation-ordered. In comparison to (001)-oriented PST films, (111)-oriented films on SrRuO{sub 3}/SrTiO{sub 3} (111) exhibited enhanced ferroelectric and dielectric properties with a broad size distribution of cation-ordered domains (5–100?nm). At a measurement temperature of 100?K, the remnant polarization of PST (111) films is almost ?3 times larger than the remnant polarization observed for (001)-oriented PST films, which is attributed to the (111) orientation of the films, as the spontaneous polarization in PST lies close to the [111] direction. The observed dielectric constant and loss at 1?kHz were around 1145 and 0.11, respectively. The dielectric constant is thus almost three times higher than for previously reported (001)-oriented PST thin films, most probably due to the enhancement in cation-ordering.

  1. Propane ammoxidation over the Mo-V-Te-Nb-O M1 phase: Reactivity of surface cations in hydrogen abstraction steps

    SciTech Connect (OSTI)

    Muthukumar, Kaliappan [University of Cincinnati; Yu, Junjun [University of Cincinnati; Xu, Ye [ORNL; Guliants, Vadim V. [University of Cincinnati

    2011-01-01T23:59:59.000Z

    Density functional theory calculations (GGA-PBE) have been performed to investigate the adsorption of C3 (propane, isopropyl, propene, and allyl) and H species on the proposed active center present in the surface ab planes of the bulk Mo-V-Te-Nb-O M1 phase in order to better understand the roles of the different surface cations in propane ammoxidation. Modified cluster models were employed to isolate the closely spaced V=O and Te=O from each other and to vary the oxidation state of the V cation. While propane and propene adsorb with nearly zero adsorption energy, the isopropyl and allyl radicals bind strongly to V=O and Te=O with adsorption energies, {Delta}E, being {le} -1.75 eV, but appreciably more weakly on other sites, such as Mo=O, bridging oxygen (Mo-O-V and Mo-O-Mo), and empty metal apical sites ({Delta}E > -1 eV). Atomic H binds more strongly to Te = O ({Delta}E {le} -3 eV) than to all the other sites, including V = O ({Delta}E = -2.59 eV). The reduction of surface oxo groups by dissociated H and their removal as water are thermodynamically favorable except when both H atoms are bonded to the same Te=O. Consistent with the strong binding of H, Te=O is markedly more active at abstracting the methylene H from propane (E{sub a} {le} 1.01 eV) than V = O (E{sub a} = 1.70 eV on V{sup 5+} = O and 2.13 eV on V{sup 4+} = O). The higher-than-observed activity and the loose binding of Te = O moieties to the mixed metal oxide lattice of M1 raise the question of whether active Te = O groups are in fact present in the surface ab planes of the M1 phase under propane ammoxidation conditions.

  2. db03.book

    National Nuclear Security Administration (NNSA)

    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 742EnergyOn AprilAElectronic Input Options Gary L. Hirsch SNLMaythe InteriorWater Resources Data

  3. LANS DB PENSION PLAN

    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 SchoolIn12electron 9 5 - -/e),,s - 6157Bioenergy » CPO:mission

  4. Core Coupling in Nb-99

    E-Print Network [OSTI]

    Bindal, P. K.; Youngblood, David H.

    1974-01-01T23:59:59.000Z

    Foundation. H. Ohnuma and J. L. Yntema, Phys. Rev. 176, 1416 (1968). 2R. L. Kozub and D. H. Youngblood, Phys. Rev. C 7, 410 (1973), and references therein. ~B. M. Preedom, E. Newman, and J. C. Hiebert, Phys. Rev. 166, 1156 (1968). 4J. Eidens, E. Roeckl..., and P. Armbruster, Nucl. Phys. A 141, 289 (1970). SReceived from P. D. Kunz, University of Colorado. 8R. L. Kozub and D. H. Youngblood, Phys. Rev. C 4, 535 (1971). ~D. H. Youngblood, R. L. Kozub, P. K. Bindal, and P. Hoffmann...

  5. Scandium induced structural transformation and B?:B? cationic ordering in Pb(Fe{sub 0.5}Nb{sub 0.5})O{sub 3} multiferroic ceramics

    SciTech Connect (OSTI)

    Mallesham, B.; Ranjith, R., E-mail: ranjith@iith.ac.in [Department of Materials Science and Metallurgical Engineering, Indian Institute of Technology Hyderabad, Ordnance Factory Estate, Yeddumailaram 502205 (India); Manivelraja, M. [Defence Metallurgical Research Laboratory, Hyderabad 500058 (India)

    2014-07-21T23:59:59.000Z

    The current study explores non-magnetic Sc{sup 3+} induced structural transformation, evolution of local B-site cation ordering and associated effect on ferroelectric phase transition temperature T{sub max} (temperature corresponding to dielectric maxima) on increasing the atom percent of Sc substitution in [Pb(Fe{sub 0.5}Nb{sub 0.5})O{sub 3} (PFN)] ceramics. In this regard, the phase pure Pb[(Fe{sub 0.5?x}Sc{sub x})Nb{sub 0.5}]O{sub 3} ceramics with x varying from 0 to 0.5 were synthesized through solid state reaction route. The detailed structural analysis through Rietveld refinement confirms the room temperature transformation from a monoclinic Cm to rhombohedral R3m structure at x?=?0.3?mol.?% of Sc. Absorption spectra studies show that there is a considerable increment in the bandgap at higher scandium content. Most interestingly, the T{sub max} exhibited an increment for lower scandium contents (x?=?0.1 to 0.25) followed by a drop in T{sub max} (x?=?0.3 to 0.5). Such anomalous behavior in T{sub max} is expected to arise due to the onset of B?, B? local cation ordering beyond Sc content x?=?0.25. The B-site cation ordering at and beyond x?=?0.3 was also confirmed by the evolution of cation order induced Pb-O coupled vibrational mode in Raman scattering studies. In addition, the Mössbauer spectra of PFN (x?=?0) and Pb(Fe{sub 0.4}Sc{sub 0.1}Nb{sub 0.5})O{sub 3} (x?=?0.1) are reported to verify the spin state and oxidation state of iron. The lattice distortion due to the radius ratio difference between a Sc{sup 3+} cation and Fe{sup 3+} cation in low spin state is responsible for the structural transformation, which in turn facilitates a B?:B? cation ordering.

  6. Extrinsic mechanism for giant dielectric response in Ba{sub 0.70}Sr{sub 0.30}(Fe{sub 0.5}Nb{sub 0.5})O{sub 3} ceramic

    SciTech Connect (OSTI)

    Patel, Piyush Kumar, E-mail: klyadav35@yahoo.com; Yadav, K. L., E-mail: klyadav35@yahoo.com; Durgesh, E-mail: klyadav35@yahoo.com [Smart Materials Research Laboratory, Department of Physics, Indian Institute of Technology Roorkee, Roorkee-247667 (India)

    2014-04-24T23:59:59.000Z

    To obtain the high dielectric constant, the effect of sintering process on the electrical properties of Ba{sub 0.70}Sr{sub 0.30}(Fe{sub 0.5}Nb{sub 0.5})O{sub 3} ceramics were investigated. X-ray diffraction pattern of the samples at room temperature shows a monoclinic structure. Microstructure analysis shows well-grown and dense microstructure in all the samples. We found giant dielectric constant (?3.59 × 10{sup 5}) with low dielectric loss (?0.49) at room temperature for 2 hr sintered sample at 1250 °C. The extrinsic phenomena like interfacial polarization due to space charge accumulation at grain boundaries are discussed.

  7. Measurement and simulation of the cross sections for nuclide production in {sup 93}Nb and {sup nat}Ni targets irradiated with 0.04- to 2.6-GeV protons

    SciTech Connect (OSTI)

    Titarenko, Yu. E., E-mail: Yury.Titarenko@itep.ru; Batyaev, V. F.; Titarenko, A. Yu.; Butko, M. A.; Pavlov, K. V.; Florya, S. N.; Tikhonov, R. S.; Zhivun, V. M. [Institute for Theoretical and Experimental Physics (Russian Federation); Ignatyuk, A. V. [Institute of Physics and Power Engineering (Russian Federation); Mashnik, S. G. [Los Alamos National Laboratory (United States); Leray, S.; Boudard, A. [CEA (France); Cugnon, J.; Mancusi, D. [University of Liege (Belgium); Yariv, Y. [SoreqNRC (Israel); Nishihara, K.; Matsuda, N. [JAEA (Japan); Kumawat, H. [BARC (India); Mank, G. [IAEA (Austria); Gudowski, W. [Royal Institute of Technology (Sweden)

    2011-04-15T23:59:59.000Z

    The cross sections for nuclide production in thin {sup 93}Nb and {sup nat}Ni targets irradiated by 0.04- to 2.6-GeV protons have been measured by direct {gamma} spectrometry using two {gamma} spectrometers with the resolutions of 1.8 and 1.7 keV in the {sup 60}Co 1332-keV {gamma} line. As a result, 1112 yields of radioactive residual nuclei have been obtained. The {sup 27}Al(p, x){sup 22}Na reaction has been used as a monitor reaction. The experimental data have been compared with the MCNPX (BERTINI, ISABEL), CEM03.02, INCL4.2, INCL4.5, PHITS, and CASCADE07 calculations.

  8. Programming T.A. Standish Languages Editor

    E-Print Network [OSTI]

    Goldstein, Seth Copen

    of the Association for Computing Machinery. Author's address: Burroughs, Plataanstraat 5, Nuenen--4565

  9. TA-55: LANL Plutonium-Processing Facilities

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

    chemistry; nuclear materials separation, processing, and recovery; plutonium metallurgy, preparation, casting, fabrication, and recovery; machining and metallurgy...

  10. TA-55: LANL Plutonium-Processing Facilities

    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'sis Taking Over Our InstagramStructureProposed Action(InsertAbout theSystems LongFacilityTTA-55:

  11. M I C R O S C A L E Z N S P E C I AT I O N I N A S M E LT E R -C O N TA M I N AT E D S O I L U S I N G MICRO-XAS AND XRE TECHNIQUES

    E-Print Network [OSTI]

    Sparks, Donald L.

    M I C R O S C A L E Z N S P E C I AT I O N I N A S M E LT E R - C O N TA M I N AT E D S O I L U S I the speciation of Zn in the soils o f B l u e M o u n t a i n . The application of spectroscopic techniques map, XANES spectra were collected on "hot spots" (areas of highest metal concentration) 100 eV below

  12. Thermotransport of hydrogen in niobium and tantalum as a function of hydrogen concentration

    SciTech Connect (OSTI)

    Kim, S.J.

    1984-01-01T23:59:59.000Z

    Transport of hydrogen in Nb and Ta has been measured in an extended hydrogen concentration range up to 0.3 (H/M) atomic ratio. In these high concentrations where the activity coefficient is not constant with concentration, the heat of transport is defined based on an activity ratio. Using the square root of the hydrogen pressure versus hydrogen concentration curves extrapolated from the curves measured by Veleckis and Edwards, the activity ratios were calculated from the measured concentrations. The absolute thermoelectric power of Nb and Ta has been measured in the same hydrogen concentration range in order to check the relationship, which was predicted by Huntington, between the absolute thermoelectric power and the heat of transport. The heat of transport based on the activity ratio, Q*(a/sub H//a/sub C/), decreased as the hydrogen concentration increased in both Nb and Ta. The heat of transport based on the hydrogen concentration ratio, Q*(C/sub H//C/sub C/), decreased in Ta but increased in Nb as the hydrogen concentration increased. The absolute thermoelectric power of Nb and Ta increased as the hydrogen concentration increased.

  13. Disrupted G{sub 1} to S phase clearance via cyclin signaling impairs liver tissue repair in thioacetamide-treated type 1 diabetic rats

    SciTech Connect (OSTI)

    Devi, Sachin S. [Department of Toxicology, School of Pharmacy, College of Health Sciences, University of Louisiana at Monroe, 700 University Avenue, Sugar Hall no. 306, Monroe, LA 71209-0470 (United States); Mehendale, Harihara M. [Department of Toxicology, School of Pharmacy, College of Health Sciences, University of Louisiana at Monroe, 700 University Avenue, Sugar Hall no. 306, Monroe, LA 71209-0470 (United States)]. E-mail: mehendale@ulm.edu

    2005-09-01T23:59:59.000Z

    Previously we reported that a nonlethal dose of thioacetamide (TA, 300 mg/kg) causes 90% mortality in type 1 diabetic (DB) rats because of irreversible acute liver injury owing to inhibited hepatic tissue repair, primarily due to blockage of G{sub 0} to S phase progression of cell division cycle. On the other hand, DB rats receiving 30 mg TA/kg exhibited equal initial liver injury and delayed tissue repair compared to nondiabetic (NDB) rats receiving 300 mg TA/kg, resulting in a delay in recovery from liver injury and survival. The objective of the present study was to test the hypothesis that impaired cyclin-regulated progression of G{sub 1} to S phase of the cell cycle may explain inhibited liver tissue repair, hepatic failure, and death, contrasted with delayed liver tissue repair but survival observed in the DB rats receiving 300 in contrast to 30 mg TA/kg. In the TA-treated NDB rats sustained MAPKs and cyclin expression resulted in higher phosphorylation of retinoblastoma (pRb), explaining prompt tissue repair and survival. In contrast, DB rats receiving the same dose of TA (300 mg/kg) exhibited suppressed MAPKs and cyclin expression that led to inhibition of pRb, inhibited tissue repair, and death. On the other hand, DB rats receiving 30 mg TA/kg exhibited delayed up regulation of MAPK signaling that delayed the expression of CD1 and pRb, explaining delayed stimulation of tissue repair observed in this group. In conclusion, the hepatotoxicant TA has a dose-dependent adverse effect on cyclin-regulated pRb signaling: the lower dose causes a recoverable delay, whereas the higher dose inhibits it with corresponding effect on the ultimate outcomes on hepatic tissue repair; this dose-dependent adverse effect is substantially shifted to the left of the dose response curve in diabetes.

  14. VOLUME 76, NUMBER 10 P H Y S I C A L R E V I E W L E T T E R S 4 MARCH 1996 Proximity Effects in Superconductor/Insulating-Ferromagnet NbN/GdN Multilayers

    E-Print Network [OSTI]

    Xiao, John Q.

    VOLUME 76, NUMBER 10 P H Y S I C A L R E V I E W L E T T E R S 4 MARCH 1996 Proximity Effects-temperature processing, which is incompatible with the fabrication of high-quality multilayers. An excep- tion is Gd temperature, using Nb (99.8% pure) and Gd (99.9% pure) targets sharing the same sputtering gas mixture of Ar

  15. In Situ Observations of Templated Grain Growth in (Na[subscript 0.5]K[subscript 0.5])[subscript 0.98]Li[subscript 0.02]NbO[subscript 3] Piezoceramics: Texture Development and Template?Matrix Interactions

    SciTech Connect (OSTI)

    Tutuncu, Goknur; Chang, Yunfei; Poterala, Stephen; Messing, Gary L.; Jones, Jacob L. (Florida); (Penn)

    2012-08-13T23:59:59.000Z

    Nucleation, texture development, and phase equilibria were observed during templated grain growth (TGG) of (Na{sub 0.5}K{sub 0.5}){sub 0.98}Li{sub 0.02}NbO{sub 3} (NKLN) via in situ X-ray diffraction (XRD). Initially, NaNbO{sub 3} templates and NKLN matrix powder exist as distinct phases with unique lattice parameters. Above 850 C, the templates and matrix begin to react via interdiffusion as characterized by an increase in diffuse scattering between the NaNbO{sub 3} and NKLN peaks. This process intensifies immediately prior to template growth, leading to merging of diffraction peaks for these two phases. TGG in this system is thus homoepitaxial in nature as it occurs after the NKLN matrix and NaNbO{sub 3} templates form a solid solution. The degree of alignment in the matrix phase is quantified in situ using the March-Dollase parameters r and f. The degree of orientation of the textured NKLN mirrors the initial alignment of the template particles (r {approx} 0.3), while the texture fraction f increases from 0.04 to {approx}0.67 after 3 h at 1138 C. This increase in texture fraction follows n = 1/3 power law kinetics consistent with liquid-phase-assisted normal grain growth on plate-like templates. As the observed template-matrix interdiffusion and the onset of texture development proceed extremely rapidly, this work demonstrates the utility of in situ XRD for observing details of TGG that cannot easily be seen via ex situ methods.

  16. Substitution behavior of x(Na{sub 0.5}K{sub 0.5})NbO{sub 3}-(1???x)BaTiO{sub 3} ceramics for multilayer ceramic capacitors by a near edge x-ray absorption fine structure analysis

    SciTech Connect (OSTI)

    Ha, Jooyeon; Ryu, Jiseung; Lee, Heesoo, E-mail: heesoo@pusan.ac.kr [School of Materials Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of)

    2014-06-30T23:59:59.000Z

    The doping effect of (Na{sub 0.5}K{sub 0.5})NbO{sub 3} (NKN) as alternatives for rare-earth elements on the electrical properties of BaTiO{sub 3} has been investigated, in terms of their substitution behavior. The dielectric constant of a specimen with x?=?0.05 was about 79% higher than that of pure BaTiO{sub 3}, and the temperature coefficient of capacitance was satisfied by the X7R specification. The specimen with x?=?0.05 showed the lowest tetragonality among the four compositions and had a fine grain size of <2 ?m. Although the addition of NKN decreased the specimen's tetragonality, the electrical properties were enhanced by the formation of defect dipoles and conduction electrons, which resulted from an acceptor and donor substitution behavior. Through O K-edge near edge x-ray absorption fine structure spectroscopy, the practical substitution behavior was defined by the change in Ti 3d orbital states. The energy separation of the Ti 3d orbitals was more apparent with the specimen of x?=?0.05, which is related to the donor level from the donor substitution of Nb{sup 5+} ion for Ti-sites. Therefore, the simultaneous substitution of Na{sup +}/K{sup +} and Nb{sup 5+} ions into BaTiO{sub 3} can improve dielectric properties, based on the charge-transfer process.

  17. Dual-enhancement of ferro-/piezoelectric and photoluminescent performance in Pr{sup 3+} doped (K{sub 0.5}Na{sub 0.5})NbO{sub 3} lead-free ceramics

    SciTech Connect (OSTI)

    Wei, Yongbin; Jia, Yanmin, E-mail: wuzheng@zjnu.cn, E-mail: ymjia@zjnu.edu.cn; Wu, Jiang; Shen, Yichao [Department of Physics, Zhejiang Normal University, Jinhua 321004 (China); Wu, Zheng, E-mail: wuzheng@zjnu.cn, E-mail: ymjia@zjnu.edu.cn [College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004 (China); Luo, Haosu [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2014-07-28T23:59:59.000Z

    A mutual enhancement action between the ferro-/piezoelectric polarization and the photoluminescent performance of rare earth Pr{sup 3+} doped (K{sub 0.5}Na{sub 0.5})NbO{sub 3} (KNN) lead-free ceramics is reported. After Pr{sup 3+} doping, the KNN ceramics exhibit the maximum enhancement of ?1.2 times in the ferroelectric remanent polarization strength and ?1.25 times in the piezoelectric coefficient d{sub 33}, respectively. Furthermore, after undergoing a ferro-/piezoelectric polarization treatment, the maximum enhancement of ?1.3 times in photoluminescence (PL) was observed in the poled 0.3% Pr{sup 3+} doped sample. After the trivalent Pr{sup 3+} unequivalently substituting the univalent (K{sub 0.5}Na{sub 0.5}){sup +}, A-sites ionic vacancies will occur to maintain charge neutrality, which may reduce the inner stress and ease the domain wall motions, yielding to the enhancement in ferro-/piezoelectric performance. The polarization-induced enhancement in PL is attributed to the decrease of crystal symmetry abound the Pr{sup 3+} ions after polarization. The dual-enhancement of the ferro-/piezoelectric and photoluminescent performance makes the Pr{sup 3+} doped KNN ceramic hopeful for piezoelectric/luminescent multifunctional devices.

  18. Structures, electrical properties, and leakage current behaviors of un-doped and Mn-doped lead-free ferroelectric K{sub 0.5}Na{sub 0.5}NbO{sub 3} films

    SciTech Connect (OSTI)

    Wang, Lingyan, E-mail: l.y.wang@mail.xjtu.edu.cn, E-mail: wren@mail.xjtu.edu.cn; Ren, Wei, E-mail: l.y.wang@mail.xjtu.edu.cn, E-mail: wren@mail.xjtu.edu.cn; Shi, Peng; Wu, Xiaoqing [Electronic Material Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an 710049 (China)

    2014-01-21T23:59:59.000Z

    Lead-free ferroelectric un-doped and doped K{sub 0.5}Na{sub 0.5}NbO{sub 3} (KNN) films with different amounts of manganese (Mn) were prepared by a chemical solution deposition method. The thicknesses of all films are about 1.6??m. Their phase, microstructure, leakage current behavior, and electrical properties were investigated. With increasing the amounts of Mn, the crystallinity became worse. Fortunately, the electrical properties were improved due to the decreased leakage current density after Mn-doping. The study on leakage behaviors shows that the dominant conduction mechanism at low electric field in the un-doped KNN film is ohmic mode and that at high electric field is space-charge-limited and Pool-Frenkel emission. After Mn doping, the dominant conduction mechanism at high electric field of KNN films changed single space-charge-limited. However, the introduction of higher amount of Mn into the KNN film would lead to a changed conduction mechanism from space-charge-limited to ohmic mode. Consequently, there exists an optimal amount of Mn doping of 2.0?mol.?%. The 2.0?mol.?% Mn doped KNN film shows the lowest leakage current density and the best electrical properties. With the secondary ion mass spectroscopies and x-ray photoelectron spectroscopy analyses, the homogeneous distribution in the KNN films and entrance of Mn element in the lattice of KNN perovskite structure were also confirmed.

  19. Enhanced dielectric constant and relaxor behavior realized by dual stage sintering of Sr{sub 0.5}Ba{sub 0.5}Nb{sub 2}O{sub 6}

    SciTech Connect (OSTI)

    Rathore, Satyapal S., E-mail: satish.vitta@iitb.ac.in; Vitta, Satish, E-mail: satish.vitta@iitb.ac.in [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai- 400076 (India)

    2014-04-24T23:59:59.000Z

    The relaxor ferroelectric compound, Sr{sub 0.5}Ba{sub 0.5}Nb{sub 2}O{sub 6} (SBN50) was synthesized by solid state reaction followed by sintering under two different conditions: single and dual stage sintering. The impact of sintering process on structural and dielectric properties has been studied in detail using X-ray diffraction, scanning electron microscopy and broadband dielectric spectroscopy. The crystal structure determined by performing Rietveld refinement of X-ray diffractogram was found to be identical in both cases. SBN50 crystallizes in the ferroelectric tetragonal tungsten bronze, P4bm structure. It was observed that uniform grain growth can be controlled by dual stage sintering and relatively narrow distribution of grains can be achieved with an average grain size of ?15 ?m. The dielectric studies show that SBN50 exhibits a relaxor ferroelectric behavior with the transformation taking place at ? 380 K due to formation of polar nano regions. Although both single and dual stage sintered SBN50 exhibits relaxor behaviour, the maximum dielectric constant of dual stage sintered SBN50 is found to be 1550 compare to 1440 for single stage sintering.

  20. Dielectric spectroscopy of Dy{sub 2}O{sub 3} doped (K{sub 0.5}Na{sub 0.5})NbO{sub 3} piezoelectric ceramics

    SciTech Connect (OSTI)

    Mahesh, P., E-mail: pamu@iitg.ernet.in; Subhash, T., E-mail: pamu@iitg.ernet.in; Pamu, D., E-mail: pamu@iitg.ernet.in [Department of Physics, Indian Institute of Technology, Guwahati-781039 (India)

    2014-04-24T23:59:59.000Z

    We report the dielectric properties of (K{sub 0.5}Na{sub 0.5})NbO{sub 3} ceramics doped with x wt% of Dy{sub 2}O{sub 3} (x= 0.0-1.5 wt%) using the broadband dielectric spectroscopy. The X-ray diffraction studies showed the formation of perovskite structure signifying that Dy{sub 2}O{sub 3} diffuse into the KNN lattice. Samples doped with x > 0.5 wt% exhibit smaller grain size and lower relative densities. The dielectric properties of KNN ceramics doped with Dy{sub 2}O{sub 3} are enhanced by increasing the Dy{sup 3+} content; among the compositions studied, x = 0.5 wt% exhibited the highest dielectric constant and lowest loss at 1MHz over the temperature range of 30°C to 400°C. All the samples exhibit maximum dielectric constant at the Curie temperature (? 326°C) and a small peak in the dielectric constant at around 165°C is due to a structural phase transition.