Sample records for ni pd pt

  1. Geometric structures of thin film: Pt on Pd(110) and NiO on Ni(100)

    SciTech Connect (OSTI)

    Warren, O.L.

    1993-07-01T23:59:59.000Z

    This thesis is divided into 3 papers: dynamical low-energy electron- diffraction investigation of lateral displacements in topmost layer of Pd(110); determination of (1{times}1) and (1{times}2) structures of Pt thin films on Pd(110) by dynamical low-energy electron-diffraction analysis; and structural determination of a NiO(111) film on Ni(100) by dynamical low-energy electron-diffraction analysis.

  2. Chemical bonding in EuTGe (T=Ni, Pd, Pt) and physical properties of EuPdGe

    SciTech Connect (OSTI)

    Rocquefelte, Xavier [UMR 6226 Sciences Chimiques de Rennes, Universite de Rennes 1-ENSC Rennes-CNRS, Avenue du General Leclerc, F-35042 Rennes Cedex (France); Gautier, Regis [UMR 6226 Sciences Chimiques de Rennes, Universite de Rennes 1-ENSC Rennes-CNRS, Avenue du General Leclerc, F-35042 Rennes Cedex (France); Halet, Jean-Francois [UMR 6226 Sciences Chimiques de Rennes, Universite de Rennes 1-ENSC Rennes-CNRS, Avenue du General Leclerc, F-35042 Rennes Cedex (France)], E-mail: halet@univ-rennes1.fr; Muellmann, Ralf [Institut fuer Physikalische Chemie, Universitaet Muenster, Corrensstrasse 30, D-48149 Muenster (Germany); Rosenhahn, Carsten [Institut fuer Physikalische Chemie, Universitaet Muenster, Corrensstrasse 30, D-48149 Muenster (Germany); Mosel, Bernd D. [Institut fuer Physikalische Chemie, Universitaet Muenster, Corrensstrasse 30, D-48149 Muenster (Germany); Kotzyba, Gunter [Institut fuer Anorganische und Analytische Chemie, Universitaet Muenster, Corrensstrasse 30, D-48149 Muenster (Germany); Poettgen, Rainer [Institut fuer Anorganische und Analytische Chemie, Universitaet Muenster, Corrensstrasse 30, D-48149 Muenster (Germany)], E-mail: pottgen@uni-muenster.de

    2007-02-15T23:59:59.000Z

    EuPdGe was prepared from the elements by reaction in a sealed tantalum tube in a high-frequency furnace. Magnetic susceptibility measurements show Curie-Weiss behavior above 60 K with an experimental magnetic moment of 8.0(1){mu} {sub B}/Eu indicating divalent europium. At low external fields antiferromagnetic ordering is observed at T {sub N}=8.5(5) K. Magnetization measurements indicate a metamagnetic transition at a critical field of 1.5(2) T and a saturation magnetization of 6.4(1){mu} {sub B}/Eu at 5 K and 5.5 T. EuPdGe is a metallic conductor with a room-temperature value of 5000{+-}500 {mu}{omega} cm for the specific resistivity. {sup 151}Eu Moessbauer spectroscopic experiments show a single europium site with an isomer shift of {delta}=-9.7(1) mm/s at 78 K. At 4.2 K full magnetic hyperfine field splitting with a hyperfine field of B=20.7(5) T is observed. Density functional calculations show the similarity of the electronic structures of EuPdGe and EuPtGe. T-Ge interactions (T=Pd, Pt) exist in both compounds. An ionic formula splitting Eu{sup 2+} T {sup 0}Ge{sup 2-} seems more appropriate than Eu{sup 2+} T {sup 2+}Ge{sup 4-} accounting for the bonding in both compounds. Geometry optimizations of EuTGe (T=Ni, Pt, Pd) show weak energy differences between the two structural types. - Graphical abstract: Cutouts of the [PdGe] and [PtGe] polyanions in the structures of EuPdGe and EuPtGe. Atom designations and some relevant interatomic distances are given.

  3. Middle distillate hydrotreatment zeolite catalysts containing Pt/Pd or Ni

    E-Print Network [OSTI]

    Marin-Rosas, Celia

    2009-05-15T23:59:59.000Z

    was financially supported by Instituto Mexicano del Petroleo, Mexico. As a scholarship student, I would like to thank all managers for their help and services. The support provided by Dr. Kenneth Hall in the final step of my research when he was the department....S., Universidad Nacional Autonoma de Mexico, Mexico; M.S., Instituto Politecnico Nacional, Mexico Co-Chairs of Advisory Committee: Dr. Gilbert F. Froment Dr. Rayford G. Anthony A study on middle distillate hydrotreatment zeolite catalysts containing Pt...

  4. EuTZn (T=Pd, Pt, Au) with TiNiSi-type structure-Magnetic properties and {sup 151}Eu Moessbauer spectroscopy

    SciTech Connect (OSTI)

    Mishra, Trinath; Hermes, Wilfried; Harmening, Thomas; Eul, Matthias [Institut fuer Anorganische und Analytische Chemie and NRW Graduate School of Chemistry, Westfaelische Wilhelms-Universitaet Muenster, Corrensstrasse 30, 48149 Muenster (Germany); Poettgen, Rainer, E-mail: pottgen@uni-muenster.d [Institut fuer Anorganische und Analytische Chemie and NRW Graduate School of Chemistry, Westfaelische Wilhelms-Universitaet Muenster, Corrensstrasse 30, 48149 Muenster (Germany)

    2009-09-15T23:59:59.000Z

    The europium compounds EuTZn (T=Pd, Pt, Au) were synthesized from the elements in sealed tantalum tubes in an induction furnace. These intermetallics crystallize with the orthorhombic TiNiSi-type structure, space group Pnma. The structures were investigated by X-ray diffraction on powders and single crystals: a=732.3(2), b=448.5(2), c=787.7(2) pm, R{sub 1}/wR{sub 2}=0.0400/0.0594, 565 F{sup 2} values for EuPdZn, a=727.8(3), b=443.7(1), c=781.7(3) pm, R{sub 1}/wR{sub 2}=0.0605/0.0866, 573 F{sup 2} values for EuPtZn, and a=747.4(2), b=465.8(2), c=789.1(4) pm, R{sub 1}/wR{sub 2}=0.0351/0.0590, 658 F{sup 2} values for EuAuZn, with 20 variables per refinement. Together the T and zinc atoms build up three-dimensional [TZn] networks with short T-Zn distances. The EuTZn compounds show Curie-Weiss behavior in the temperature range from 75 to 300 K with mu{sub eff}=7.97(1), 7.70(1), and 7.94(1) mu{sub B}/Eu atom and theta{sub P}=18.6(1), 34.9(1), and 55.5(1) K for T=Pd, Pt, and Au, respectively, indicating divalent europium. Antiferromagntic ordering was detected at 15.1(3) K for EuPdZn and canted ferromagnetic ordering at 21.2(3) and 51.1(3) K for EuPtZn and EuAuZn. {sup 151}Eu Moessbauer spectroscopic measurements confirm the divalent nature of the europium atoms by isomer shift values ranging from -8.22(8) (EuPtZn) to -9.23(2) mm/s (EuAuZn). At 4.2 K full magnetic hyperfine field splitting is observed in all three compounds due to magnetic ordering of the europium magnetic moments. - Graphical abstract: Europium coordination in EuPdZn, EuPtZn, and EuAuZn.

  5. Catalyst and process development for hydrogen preparation from future fuel cell feedstocks. Quarterly progress report, January 1, 1980-March 31, 1980. [Pt/Rh, Pd, Pt, Rh, Ni/Rh, Rh/Re, Ni

    SciTech Connect (OSTI)

    Yarrington, R M; Feins, I R; Hwang, H S

    1980-04-01T23:59:59.000Z

    Catalysts are being screened to steam reform hydrocarbons in an autothermal reformer (STR). Twenty-one samples have been screened in a 1-in.-diam (ATR) reactor using No. 2 oil as the hydrocarbon feed. A series of platinum-rhodium catalysts were evaluated to study the effect of varying compositions. A sample containing 1.7% Pt/0.3% Rh was most active but the difference among the samples was within the range of test variability. Development of a more realistic test has been started. The effect of O/sub 2//C level on the gas composition leaving the catalytic partial oxidation section has been determined. The amount of unreacted oil increases as O/sub 2//C level decreases. The unreacted oil is more aromatic than the feedstock. The gas composition contains considerably more olefins as the O/sub 2//C level decreases. Post-run catalyst characterization indicates that the catalyst carrier does not deteriorate in the ATR test. A drastic decrease in CO chemisorption is noted on the Pt/Rh samples. This decline in CO chemisorption could either be due to metal sintering or to carbon deposition on the metal. Other analysis are required to determine which is causing the decline in CO chemisorption. Very low coke levels were found on Pt, Rh, and Pt/Rh samples. Addition of Rh to nickel reduces the coke level over that observed for nickel catalysts.

  6. Deactivation Mechanisms of Pt/Pd-based Diesel Oxidation Catalysts...

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

    Oh, DB Brown, DH Kim, JH Lee, and CHF Peden.2012."Deactivation Mechanisms of PtPd-based Diesel Oxidation Catalysts."Catalysis Today 184(1):197-204. doi:10.1016...

  7. Reaction-Driven Restructuring of Rh-Pd and Pt-Pd Core-Shell Nanoparticles

    SciTech Connect (OSTI)

    Tao, Feng; Grass, Michael E.; Zhang, Yawen; Butcher, Derek R.; Renzas, James R.; Liu, Zhi; Chung, Jen Y.; Mun, Bongjin S.; Salmeron, Miquel; Somorjai, Gabor A.

    2009-06-17T23:59:59.000Z

    The structure and composition of core-shell Rh{sub 0.5}Pd{sub 0.5} and Pt{sub 0.5}Pd{sub 0.5} nanoparticle catalysts were studied in situ, during oxidizing, reducing, and catalytic reactions involving NO, O{sub 2}, CO, and H{sub 2} using X-ray photoelectron spectroscopy in the Torr pressure range. The Rh{sub 0.5}Pd{sub 0.5} nanoparticles undergo dramatic and reversible changes in composition and chemical state in response to oxidizing or reducing conditions. Under oxidizing conditions the Rh atoms segregate to the shell region while in reducing atmospheres the Pd atoms diffuse to the shell region. In contrast no significant segregation of Pd or Pt atoms was found in Pt{sub 0.5}Pd{sub 0.5} nanoparticles. The distinct behavior in restructuring and chemical response of Rh{sub 0.5}Pd{sub 0.5} and Pt{sub 0.5}Pd{sub 0.5} nanoparticle catalysts under the same reaction conditions illustrates the flexibility and tunability of the structure of bimetallic nanoparticle catalysts during catalytic reactions.

  8. Preparation of PtNi Nanoparticles for the Electrocatalytic Oxidation of Methanol

    E-Print Network [OSTI]

    Deivaraj, T.C.

    Carbon supported PtNi nanoparticles were prepared by hydrazine reduction of Pt and Ni precursor salts under different conditions, namely by conventional heating (PtNi-1), by prolonged reaction at room temperature (PtNi-2) ...

  9. Crystalline Ice Growth on Pt(111) and Pd(111): Nonwetting Growth...

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

    Crystalline Ice Growth on Pt(111) and Pd(111): Nonwetting Growth on a Hydrophobic Water Monolayer. Crystalline Ice Growth on Pt(111) and Pd(111): Nonwetting Growth on a Hydrophobic...

  10. Growth of Epitaxial Thin Pd(111) Films on Pt(111) and Oxygen...

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

    Growth of Epitaxial Thin Pd(111) Films on Pt(111) and Oxygen-Terminated FeO(111) Surfaces . Growth of Epitaxial Thin Pd(111) Films on Pt(111) and Oxygen-Terminated FeO(111)...

  11. A photoemission study of Pd ultrathin films on Pt(111)

    SciTech Connect (OSTI)

    Mun, Bongjin Simon; Lee, Choongman; Stamenkovic, Vojislav; Markovic, Nenad M.; Ross Jr., Philip N.

    2005-05-11T23:59:59.000Z

    The origin of surface core-level shift (SCLS) of Pd thin films on Pt(111) substrate is investigated. At sub-monolayer coverage of Pd thin films, the splitting of Pd 3d core level peaks indicate the contribution of both initial and final-state of photo-ionization processes while there is almost no change on valence band (VB) spectra. When the coverage of Pd reaches to single monolayer, the final-state relaxation effect on the Pd 3d vanishes and only the initial-state effect, a negative SCLS, is present. Also, the VB spectrum at Pd monolayer films shows a clear band narrowing, that is the origin of the negative SCLS at monolayer coverage. As the Pd coverage is increased to more than monolayer thickness, the Pd 3d peaks start to show the surface layer contribution from second and third layers, positive SCLS, and the VB spectrum shows even narrower band width, possibly due to the formation of surface states and strained effect of Pd adlayers on top of the first pseudomorphic layer.

  12. CO adsorption and kinetics on well-characterized Pd films on Pt(111) in alkaline solutions

    E-Print Network [OSTI]

    Arenz, M.; Stamenkovic, V.; Wandelt, K.; Ross, P.N.; Markovic, N.M.

    2002-01-01T23:59:59.000Z

    voltammetric profiles of Pt(111)-xPd surfaces. The correlation between the PdPd films were prepared and well characterized in UHV and subsequently transferred into the electrochemical cell for the registration of the voltammetric profiles.

  13. Mechanism of olefin production on Pt, Rh, and Pd catalysts

    SciTech Connect (OSTI)

    Huff, M.; Schmidt, L.D. [Univ. of Minnesota, Minneapolis, MN (United States)

    1995-12-01T23:59:59.000Z

    The partial oxidation of ethylene, propylene, and butylene in an autothermal reactor at atmospheric pressure with contact times less that {approximately}10 milliseconds leads to high selectivities to mono-olefins over Pt/Al{sub 2}O{sub 3}, synthesis gas over Rh/Al{sub 2}O{sub 3}, and rapid carbon deposition and deactivation over Pd/Al{sub 2}O{sub 3} at complete oxygen conversion and high alkane conversion. In all cases, thermodynamics predicts carbon deposition. We will show how the product distributions vary with choice of catalyst and reaction conditions. We will use an elementary step model based on surface reaction rates on the various metals obtained from the surface science literature to simulate these experimental results. The dominant reaction pathways on the different metals can be explained by the relative preference for {beta} elimination reactions on Pt, nearly even split between {alpha} and {beta} elimination on Rh, and rapid {alpha} elimination on Pd.

  14. Synthesis of Pd?Ru@Pt nanoparticles for oxygen reduction reaction in acidic electrolytes

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

    Sun, Yu; Hsieh, Yu-Chi; Chang, Li-Chung; Wu, Pu-Wei; Lee, Jyh-Fu

    2015-03-01T23:59:59.000Z

    Nanoparticles of PdRu, Pd?Ru, and Pd?Ru are synthesized and impregnated on carbon black via a wet chemical reflux process. X-ray diffraction patterns of the as-synthesized samples, PdxRu/C (x=1/3/9), suggest succesful formation of alloy without presence of individual Pd and Ru nanoparticles. Images from transmission electron microscope confirm irregularly-shaped nanoparticles with average size below 3 nm. Analysis from extended X-ray absorption fine structure on both Pd and Ru K-edge absorption profiles indicate the Ru atoms are enriched on the surface of PdxRu/C. Among these samples, the Pd?Ru/C exhibits the strongest electrocatalytic activity for oxygen reduction reaction (ORR) in an oxygen-saturated 0.1more »M aqueous HClO? solution. Subsequently, the Pd?Ru/C undegoes Cu under potential deposition, followed by a galvanic displacement reaction to deposit a Pt monolayer on the Pd?Ru surface (Pd?Ru@Pt). The Pd?Ru@Pt reveals better ORR performance than that of Pt, reaching a mass activity of 0.38 mA ?g?¹ Pt, as compared to that of commercially available Pt nanoparticles (0.107 mA ?g?¹ Pt). The mechanisms responsible for the ORR enhancement are attributed to the combined effects of lattice strain and ligand interaction. In addition, this core-shell Pd?Ru@Pt electrocatalyst represents a substantial reduction in the amount of Pt consumption and raw material cost.« less

  15. Synthesis of Pd?Ru@Pt nanoparticles for oxygen reduction reaction in acidic electrolytes

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

    Sun, Yu [National Chiao Tung Univ., Hsin-chu (Taiwan); Hsieh, Yu-Chi [Brookhaven National Lab. (BNL), Upton, NY (United States); Chang, Li-Chung [National Chiao Tung Univ., Hsin-chu (Taiwan); Wu, Pu-Wei [National Chiao Tung Univ., Hsin-chu (Taiwan); Lee, Jyh-Fu [National Synchrotron Radiation Research Center, Hsin-chu (Taiwan)

    2015-03-01T23:59:59.000Z

    Nanoparticles of PdRu, Pd?Ru, and Pd?Ru are synthesized and impregnated on carbon black via a wet chemical reflux process. X-ray diffraction patterns of the as-synthesized samples, PdxRu/C (x=1/3/9), suggest succesful formation of alloy without presence of individual Pd and Ru nanoparticles. Images from transmission electron microscope confirm irregularly-shaped nanoparticles with average size below 3 nm. Analysis from extended X-ray absorption fine structure on both Pd and Ru K-edge absorption profiles indicate the Ru atoms are enriched on the surface of PdxRu/C. Among these samples, the Pd?Ru/C exhibits the strongest electrocatalytic activity for oxygen reduction reaction (ORR) in an oxygen-saturated 0.1 M aqueous HClO? solution. Subsequently, the Pd?Ru/C undegoes Cu under potential deposition, followed by a galvanic displacement reaction to deposit a Pt monolayer on the Pd?Ru surface (Pd?Ru@Pt). The Pd?Ru@Pt reveals better ORR performance than that of Pt, reaching a mass activity of 0.38 mA ?g?¹ Pt, as compared to that of commercially available Pt nanoparticles (0.107 mA ?g?¹ Pt). The mechanisms responsible for the ORR enhancement are attributed to the combined effects of lattice strain and ligand interaction. In addition, this core-shell Pd?Ru@Pt electrocatalyst represents a substantial reduction in the amount of Pt consumption and raw material cost.

  16. The effect of specific chloride adsorption on the electrochemical behavior of ultrathin Pd films deposited on Pt(111) in acid solution

    E-Print Network [OSTI]

    Arenz, M.; Stamenkovic, V.; Schmidt, T.J.; Wandelt, K.; Ross, P.N.; Markovic, N.M.

    2002-01-01T23:59:59.000Z

    the Pd surface coverage modifies the voltammetric profilesFigure 2 voltammetric profiles of the Pt(111)-Pd electrodethe voltammetric profiles that demonstrate the effect of Pd.

  17. Pt/Pd electrocatalyst electrons for fuel cells

    DOE Patents [OSTI]

    Stonehart, P.

    1981-11-03T23:59:59.000Z

    This invention relates to improved electrochemical cells and to novel electrodes for use therein. In particular, the present invention comprises a fuel cell used primarily for the consumption of impure hydrogen fuels containing carbon monoxide or carbonaceous fuels where the electrode in contact with the fuel is not substantially poisoned by carbon monoxide. The anode of the fuel cell comprises a Pd/Pt alloy supported on a graphitized or partially graphitized carbon material. Fuel cells which comprise as essential elements a fuel electrode, an oxidizing electrode, and an electrolyte between said electrodes are devices for the direct production of electricity through the electrochemical combustion of a fuel and oxidant. These devices are recognized for their high efficiency as energy conversion units, since unlike conventional combustion engines, they are not subject to the limitations of the Carnot heat cycle. It is the primary object of the present invention to provide an electrode having high electrochemical activity for an electrochemical cell. It is another object of the present invention to provide an electrode having an electro-catalyst which is highly resistant to the corrosive environment of an electrochemical cell.

  18. Comparison of S, Pt, and Hf adsorption on NiAl(110) Karin M. Carling a

    E-Print Network [OSTI]

    Carter, Emily A.

    Gunaydin b , Tracy A. Mitchell b , Emily A. Carter a,b,* a Department of Mechanical and Aerospace. Keywords: NiAl alloy; (110) surface; Adsorption; Hf; Pt; S; DFT 1. Introduction NiAl alloys alloys either contain primarily Ni, with Cr, Al, and Y do- pants [6­8], or are based on NiAlPt alloys [9

  19. Thermomechanical Characterization of a TiPdNi High Temperature SMA under Tension

    E-Print Network [OSTI]

    Thermomechanical Characterization of a TiPdNi High Temperature SMA under Tension Parikshith K issues, a nominal composition of Ti50Pd40Ni10 HTSMA was used. The alloy was fabricated using a vacuum arc Electrode Discharge Machining (EDM). A high temperature experimental setup was developed on a load frame

  20. Monodisperse core/shell Ni/FePt nanoparticles and their con-version to Ni/Pt to catalyze oxygen reduction

    SciTech Connect (OSTI)

    Zhang, Sen [Univ. of Pennsylvania, Philadelphia, PA (United States); Su, Dong [Brookhaven National Lab. (BNL), Upton, NY (United States); Doan-Nguyen, Vicky V. T. [Univ. of Pennsylvania, Philadelphia, PA (United States); Wu, Yaoting [Univ. of Pennsylvania, Philadelphia, PA (United States); Li, Jing [Brookhaven National Lab. (BNL), Upton, NY (United States); Sun, Shouheng [Brown Univ., Providence, RI (United States); Murray, Christopher B. [Univ. of Pennsylvania, Philadelphia, PA (United States); Hao, Yizhou [Univ. of Pennsylvania, Philadelphia, PA (United States)

    2014-11-12T23:59:59.000Z

    We report a size-controllable synthesis of monodisperse core/shell Ni/FePt nanoparticles (NPs) via a seed-mediated growth and their subsequent conversion to Ni/Pt NPs. Preventing surface oxidation of the Ni seeds is essential for the growth of uniform FePt shells. These Ni/FePt NPs have a thin (? 1 nm) FePt shell, and can be converted to Ni/Pt by acetic acid wash to yield active catalysts for oxygen reduction reaction (ORR). Tuning the core size allow for optimization of their electrocatalytic activity. The specific activity and mass activity of 4.2 nm/0.8 nm core/shell Ni/FePt reach 1.95 mA/cm² and 490 mA/mgPt at 0.9 V (vs. reversible hydrogen electrode, RHE), which are much higher than those of benchmark commercial Pt catalyst (0.34 mA/cm² and 92 mA/mgPt at 0.9 V). Our studies provide a robust approach to monodisperse core/shell NPs with non-precious metal core, making it possible to develop advanced NP catalysts with ultralow Pt content for ORR and many other heterogeneous reactions.

  1. Monodisperse core/shell Ni/FePt nanoparticles and their con-version to Ni/Pt to catalyze oxygen reduction

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

    Zhang, Sen; Su, Dong; Doan-Nguyen, Vicky V. T.; Wu, Yaoting; Li, Jing; Sun, Shouheng; Murray, Christopher B.; Hao, Yizhou

    2014-11-12T23:59:59.000Z

    We report a size-controllable synthesis of monodisperse core/shell Ni/FePt nanoparticles (NPs) via a seed-mediated growth and their subsequent conversion to Ni/Pt NPs. Preventing surface oxidation of the Ni seeds is essential for the growth of uniform FePt shells. These Ni/FePt NPs have a thin (? 1 nm) FePt shell, and can be converted to Ni/Pt by acetic acid wash to yield active catalysts for oxygen reduction reaction (ORR). Tuning the core size allow for optimization of their electrocatalytic activity. The specific activity and mass activity of 4.2 nm/0.8 nm core/shell Ni/FePt reach 1.95 mA/cm² and 490 mA/mgPt at 0.9 Vmore »(vs. reversible hydrogen electrode, RHE), which are much higher than those of benchmark commercial Pt catalyst (0.34 mA/cm² and 92 mA/mgPt at 0.9 V). Our studies provide a robust approach to monodisperse core/shell NPs with non-precious metal core, making it possible to develop advanced NP catalysts with ultralow Pt content for ORR and many other heterogeneous reactions.« less

  2. Monodisperse core/shell Ni/FePt nanoparticles and their con-version to Ni/Pt to catalyze oxygen reduction

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

    Zhang, Sen [Univ. of Pennsylvania, Philadelphia, PA (United States); Su, Dong [Brookhaven National Lab. (BNL), Upton, NY (United States); Doan-Nguyen, Vicky V. T. [Univ. of Pennsylvania, Philadelphia, PA (United States); Wu, Yaoting [Univ. of Pennsylvania, Philadelphia, PA (United States); Li, Jing [Brookhaven National Lab. (BNL), Upton, NY (United States); Sun, Shouheng [Brown Univ., Providence, RI (United States); Murray, Christopher B. [Univ. of Pennsylvania, Philadelphia, PA (United States); Hao, Yizhou [Univ. of Pennsylvania, Philadelphia, PA (United States)

    2014-11-12T23:59:59.000Z

    We report a size-controllable synthesis of monodisperse core/shell Ni/FePt nanoparticles (NPs) via a seed-mediated growth and their subsequent conversion to Ni/Pt NPs. Preventing surface oxidation of the Ni seeds is essential for the growth of uniform FePt shells. These Ni/FePt NPs have a thin (? 1 nm) FePt shell, and can be converted to Ni/Pt by acetic acid wash to yield active catalysts for oxygen reduction reaction (ORR). Tuning the core size allow for optimization of their electrocatalytic activity. The specific activity and mass activity of 4.2 nm/0.8 nm core/shell Ni/FePt reach 1.95 mA/cm² and 490 mA/mgPt at 0.9 V (vs. reversible hydrogen electrode, RHE), which are much higher than those of benchmark commercial Pt catalyst (0.34 mA/cm² and 92 mA/mgPt at 0.9 V). Our studies provide a robust approach to monodisperse core/shell NPs with non-precious metal core, making it possible to develop advanced NP catalysts with ultralow Pt content for ORR and many other heterogeneous reactions.

  3. High Performance Plasma Sputtered PdPt Fuel Cell Electrodes with Ultra Low Loading

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    : the catalyst of a fuel cell can cost no more than 5/3 per kilowatt [1]. If the catalyst is platinum (~40 g-1High Performance Plasma Sputtered PdPt Fuel Cell Electrodes with Ultra Low Loading M. Mougenot1, 2 potential for the fuel cell technology to overcome the upcoming energy and resources issues in our society

  4. Surface segregation effects in electrocatalysis: Kinetics ofoxygen reduction reaction on polycrystalline Pt3Ni alloy surfaces

    SciTech Connect (OSTI)

    Stamenkovic, V.; Schmidt, T.J.; Ross, P.N.; Markovic, N.M.

    2002-11-01T23:59:59.000Z

    Effects of surface segregation on the oxygen reduction reaction (ORR) have been studied on a polycrystalline Pt3Ni alloy in acid electrolyte using ultra high vacuum (UHV) surface sensitive probes and the rotating ring disk electrode (RRDE) method. Preparation, modification and characterization of alloy surfaces were done in ultra high vacuum (UHV). Depending on the preparation method, two different surface compositions of the Pt3Ni alloy are produced: a sputtered surface with 75 % Pt and an annealed surface (950 K ) with 100 % Pt. The latter surface is designated as the 'Pt-skin' structure, and is a consequence of surface segregation, i.e., replacement of Ni with Pt atoms in the first few atomic layers. Definitive surface compositions were established by low energy ion scattering spectroscopy (LEISS). The cyclic voltammetry of the 'Pt-skin' surface as well as the pseudocapacitance in the hydrogen adsorption/desorption potential region is similar to a polycrystalline Pt electrode. Activities of ORR on Pt3Ni alloy surfaces were compared to polycrystalline Pt in 0.1M HClO4 electrolyte for the observed temperature range of 293 < T < 333 K. The order of activities at 333 K was: 'Pt-skin' > Pt3Ni (75% Pt) > Pt with the maximum catalytic enhancement obtained for the 'Pt-skin' being 4 times that for pure Pt. Catalytic improvement of the ORR on Pt3Ni and 'Pt-skin' surfaces was assigned to the inhibition of Pt-OHad formation (on Pt sites) versus polycrystalline Pt. Production of H2O2 on both surfaces were similar compared to the pure Pt. Kinetic analyses of RRDE data confirmed that kinetic parameters for the ORR on the Pt3Ni and 'Pt-skin' surfaces are the same as on pure Pt: reaction order, m=1, two identical Tafel slopes, activation energy, {approx} 21-25 kJ/mol. Therefore the reaction mechanism on both Pt3Ni and 'Pt-skin' surfaces is the same as one proposed for pure Pt i.e. 4e{sup -} reduction pathway.

  5. Effects of aging on the characteristics of TiNiPd shape memory alloy thin films

    SciTech Connect (OSTI)

    Zhang Congchun [Key Laboratory for Thin Film and Micro-fabrication Technology of Ministry of Education, Research Institute of Micro/Nanometer Science and Technology (China)], E-mail: zhcc@mail.sjtu.edu.cn; Yang Chunsheng; Ding Guifu [Key Laboratory for Thin Film and Micro-fabrication Technology of Ministry of Education, Research Institute of Micro/Nanometer Science and Technology (China); Wu Jiansheng [School of Material Science and Engineering, Shanghai Jiaotong University, 200030, Shanghai (China)

    2008-07-15T23:59:59.000Z

    TiNiPd thin films have been deposited on glass substrate using R.F. magnetron sputtering. Effects of annealing and aging on the microstructure, phase transformation behaviors and shape memory effects of these thin films have been studied by X-ray diffractometry, differential scanning calorimeter, tensile tests and internal friction characteristics. The TiNiPd thin films annealed at 750 deg. C exhibit uniform martensite/austenite transformations and shape memory effect. Aging at 450 deg. C for 1 h improved the uniformity of transformations and shape memory effect. Long time aging decreased transformation temperatures and increased the brittleness of TiNiPd thin films.

  6. Synthesis of Pt?Pd Core?Shell Nanostructures by Atomic Layer Deposition: Application in Propane Oxidative Dehydrogenation to Propylene

    SciTech Connect (OSTI)

    Lei, Y.; Liu, Bin; Lu, Junling; Lobo-Lapidus, Rodrigo J.; Wu, Tianpin; Feng, Hao; Xia, Xiaoxing; Mane, Anil U.; Libera, Joseph A.; Greeley, Jeffrey P.; Miller, Jeffrey T.; Elam, J. W.

    2012-08-20T23:59:59.000Z

    Atomic layer deposition (ALD) was employed to synthesize supported Pt?Pd bimetallic particles in the 1 to 2 nm range. The metal loading and composition of the supported Pt?Pd nanoparticles were controlled by varying the deposition temperature and by applying ALD metal oxide coatings to modify the support surface chemistry. Highresolution scanning transmission electron microscopy images showed monodispersed Pt?Pd nanoparticles on ALD Al2O3 - and TiO2 -modi?ed SiO2 gel. X-ray absorption spectroscopy revealed that the bimetallic nanoparticles have a stable Pt-core, Pd-shell nanostructure. Density functional theory calculations revealed that the most stable surface con?guration for the Pt? Pd alloys in an H2 environment has a Pt-core, Pd-shell nanostructure. In comparison to their monometallic counterparts, the small Pt?Pd bimetallic core?shell nanoparticles exhibited higher activity in propane oxidative dehydrogenation as compared to their physical mixture.

  7. Thermomechanical Cyclic Response of TiNiPd High-Temperature Shape Memory Alloys

    E-Print Network [OSTI]

    Atli, Kadri

    2012-10-19T23:59:59.000Z

    TiNiPd high-temperature shape memory alloys (HTSMAs) have attracted considerable attention as potential solid-state actuators capable of operating at temperatures up to 500 °C, exhibiting excellent corrosion resistance, adequate ductility levels...

  8. In vitro degradation and biocompatibility of FePd and FePt composites fabricated by spark plasma sintering

    E-Print Network [OSTI]

    Zheng, Yufeng

    rate than pure iron, Fe-5 wt.%Pd and Fe-5 wt.%Pt composites were prepared by spark plasma sinteringIn vitro degradation and biocompatibility of Fe­Pd and Fe­Pt composites fabricated by spark plasma sintering T. Huang a,b , J. Cheng c , Y.F. Zheng a,b,c, a State Key Laboratory for Turbulence and Complex

  9. Correlating Extent of Pt–Ni Bond Formation with Low-temperature Hydrogenation of Benzene and 1,3-butadiene over Supported Pt/Ni Bimetallic Catalysts

    SciTech Connect (OSTI)

    Lonergan, W.; Vlachos, D; Chen, J

    2010-01-01T23:59:59.000Z

    Low-temperature hydrogenation of benzene and 1,3-butadiene on supported Pt/Ni catalysts have been used as probe reactions to correlate hydrogenation activity with the extent of Pt-Ni bimetallic bond formation. Pt/Ni bimetallic and Pt and Ni monometallic catalysts were supported on {gamma}-Al{sub 2}O{sub 3} using incipient wetness impregnation. Two sets of bimetallic catalysts were synthesized: one set to study the effect of metal atomic ratio and the other to study the effect of impregnation sequence. Fourier transform infrared spectroscopy (FTIR) CO adsorption studies were performed to characterize the surface composition of the bimetallic nanoparticles, and transmission electron microscopy (TEM) was utilized to characterize the particle size distribution. Batch reactor studies with FTIR demonstrated that all bimetallic catalysts outperformed monometallic catalysts for both benzene and 1,3-butadiene hydrogenation. Within the two sets of bimetallic catalysts, it was found that catalysts with a smaller Pt:Ni ratio possessed higher hydrogenation activity and that catalysts synthesized using co-impregnation had greater activity than sequentially impregnated catalysts. Extended X-ray absorption fine structure (EXAFS) measurements were performed in order to verify the extent of Pt-Ni bimetallic bond formation, which was found to correlate with the hydrogenation activity.

  10. Quantitative Prediction of Surface Segregation in Bimetallic Pt-MAlloy Nanoparticles (M=Ni, Re, Mo)

    SciTech Connect (OSTI)

    Wang, Guofeng; Van Hove, Michel A.; Ross, Phil N.; Baskes,Michael I.

    2005-06-20T23:59:59.000Z

    This review addresses the issue of surface segregation inbimetallic alloy nanoparticles, which are relevant to heterogeneouscatalysis, in particular for electro-catalysts of fuel cells. We describeand discuss a theoretical approach to predicting surface segregation insuch nanoparticles by using the Modified Embedded Atom Method and MonteCarlo simulations. In this manner it is possible to systematicallyexplore the behavior of such nanoparticles as a function of componentmetals, composition, and particle size, among other variables. We choseto compare Pt75Ni25, Pt75Re25, and Pt80Mo20 alloys as example systems forthis discussion, due to the importance of Pt in catalytic processes andits high-cost. It is assumed that the equilibrium nanoparticles of thesealloys have a cubo-octahedral shape, the face-centered cubic lattice, andsizes ranging from 2.5 nm to 5.0 nm. By investigating the segregation ofPt atoms to the surfaces of the nanoparticles, we draw the followingconclusions from our simulations at T= 600 K. (1) Pt75Ni25 nanoparticlesform a surface-sandwich structure in which the Pt atoms are stronglyenriched in the outermost and third layers while the Ni atoms areenriched in the second layer. In particular, a nearly pure Pt outermostsurface layer can be achieved in those nanoparticles. (2) EquilibriumPt75Re25 nanoparticles adopt a core-shell structure: a nearly pure Ptshell surrounding a more uniform Pt-Re core. (3) In Pt80Mo20nanoparticles, the facets are fully occupied by Pt atoms, the Mo atomsonly appear at the edges and vertices, and the Pt and Mo atoms arrangethemselves in an alternating sequence along the edges and vertices. Oursimulations quantitatively agree with previous experimental andtheoretical results for the extended surfaces of Pt-Ni, Pt-Re, and Pt-Moalloys. We further discuss the reasons for the different types of surfacesegregation found in the different alloys, and some of theirimplications.

  11. Characterizations Of Precipitate Phases In a Ti-Ni-Pd Alloy

    SciTech Connect (OSTI)

    Yang, Fan; Kovarik, Libor; Phillips, Patrick J.; Noebe, Ronald D.; Mills, M. J.

    2012-06-01T23:59:59.000Z

    Precipitates in the Ti46Ni37.5Pd16.5 alloy were investigated by electron diffraction and high-resolution scanning transmission electron microscopy. The phase content and stability were determined at several different temperatures and times. Aging at 400 C for an hour results in a new phase, which is consumed by P-phase at longer aging time. At 450 C, the new phase appears first, and then coexists with P-phase. At 500 C, the entire alloy transformed into the new phase. At 550 C, Ti3(Ni,Pd)4 phase begins to form.

  12. Tunable magnetization dynamics in disordered FePdPt ternary alloys: Effects of spin orbit coupling

    SciTech Connect (OSTI)

    Ma, L.; Fan, W. J., E-mail: stslts@mail.sysu.edu.cn; Chen, F. L.; Zhou, S. M. [Shanghai Key Laboratory of Special Artificial Microstructure and Pohl Institute of Solid State Physics and School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Li, S. F.; Lai, T. S., E-mail: eleanorfan@163.com [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); He, P. [Department of Physics, Fudan University, Shanghai 200433 (China); Xu, X. G.; Jiang, Y. [State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

    2014-09-21T23:59:59.000Z

    The magnetization dynamics of disordered Fe?.?(Pd{sub 1–x}Pt{sub x})?.? alloy films was studied by time-resolved magneto-optical Kerr effect and ferromagnetic resonance. The intrinsic Gilbert damping parameter ?? and the resonance linewidth change linearly with the Pt atomic concentration. In particular, the induced in-plane uniaxial anisotropy constant K{sub U} also increases for x increasing from 0 to 1. All these results can be attributed to the tuning effect of the spin orbit coupling. For the disordered ternary alloys, an approach is proposed to control the induced in-plane uniaxial anisotropy, different from conventional thermal treat methods, which is helpful to design and fabrications of spintronic devices.

  13. Microstructural Characterization and Shape Memory Response of Ni-Rich NiTiHf and NiTiZr High Temperature Shape Memory Alloys

    E-Print Network [OSTI]

    Evirgen, Alper

    2014-08-14T23:59:59.000Z

    NiTiHf and NiTiZr high temperature shape memory alloys (HTSMAs) have drawn a great deal of attention as cheaper alternatives to Pt, Pd and Au alloyed NiTi-based HTSMAs while NiTiZr alloys also providing at least 20% weight reduction then its Ni...

  14. Effect of electronic structures on catalytic properties of CuNi alloy and Pd in MeOH-related reactions

    SciTech Connect (OSTI)

    Tsai, An-Pang [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan); National Institute for Materials Science, Tsukuba 305-0047 (Japan); Kimura, Tomofumi; Suzuki, Yukinori; Kameoka, Satoshi [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan); Shimoda, Masahiko [National Institute for Materials Science, Tsukuba 305-0047 (Japan); Ishii, Yasushi [Department of Physics, Chuo University, Kasuga, Tokyo 112-8551 (Japan)

    2013-04-14T23:59:59.000Z

    We investigated the catalytic properties of a CuNi solid solution and Pd for methanol-related reactions and associated valence electronic structures. Calculations and X-ray photoelectron spectroscopy measurements revealed that the CuNi alloy has a similar valence electronic structure to Pd and hence they exhibited similar CO selectivities in steam reforming of methanol and decomposition of methanol. Samples prepared by various processes were found to have similar CO selectivities. We conjecture that alloying of Cu and Ni dramatically alters the valence electronic structures, making it similar to that of Pd so that the alloy exhibits similar catalytic properties to Pd. First-principles slab calculations of surface electronic structures support this conjecture.

  15. Tuning magnetotransport in PdPt/Y{sub 3}Fe{sub 5}O{sub 12}: Effects of magnetic proximity and spin-orbit coupling

    SciTech Connect (OSTI)

    Zhou, X.; Ma, L.; Shi, Z.; Zhou, S. M., E-mail: shiming@tongji.edu.cn [Shanghai Key Laboratory of Special Artificial Microstructure and Pohl Institute of Solid State Physics and School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Guo, G. Y., E-mail: gyguo@phys.ntu.edu.tw [Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Hu, J.; Wu, R. Q. [Department of Physics and Astronomy, University of California, Irvine, California 92697-4575 (United States)

    2014-07-07T23:59:59.000Z

    We report that anisotropic magnetoresistance (AMR) and anomalous Hall conductivity (AHC) in the Pd{sub 1?x}Pt{sub x}/Y{sub 3}Fe{sub 5}O{sub 12} (YIG) bilayers could be tuned by varying the Pt concentration (x) and also temperature (T). In particular, the AHC at low T changes its sign when x increases from 0 to 1, agreeing with the negative and positive AHC predicted by our ab initio calculations for the magnetic proximity (MP)-induced ferromagnetic Pd and Pt, respectively. The AMR ratio is enhanced by ten times when x increases from 0 to 1. Furthermore, the AMR of PdPt/YIG bilayers shows similar T-dependence as the magnetic susceptibility of the corresponding bulk Pd/Pt, also indicating the MP effect as the origin of the AMR. The present work demonstrates that the alloying of Pt and Pd not only offers tunable spin-orbit coupling but also is useful to reveal the nature of the AMR and AHC in Pt/YIG bilayers, which are useful for spintronics applications.

  16. Differentiation of O-H and C-H Bond Scission Mechanisms of Ethylene Glycol on Pt and Ni/Pt Using Theory and Isotopic Labeling Experiments

    SciTech Connect (OSTI)

    Salciccioli, Michael; Yu, Weiting; Barteau, Mark A; Chen, Jingguang; Vlachos, Dion G.

    2011-05-25T23:59:59.000Z

    Understanding and controlling bond-breaking sequences of oxygenates on transition metal catalysts can greatly impact the utilization of biomass feedstocks for fuels and chemicals. The decomposition of ethylene glycol, as the simplest representative of biomass-derived polyols, was studied via density functional theory (DFT) calculations to identify the differences in reaction pathways between Pt and the more active Ni/Pt bimetallic catalyst. Comparison of the computed transition states indicated three potentially feasible paths from ethylene glycol to C1 oxygenated adsorbates on Pt. While not important on Pt, the pathway to 1,2-dioxyethylene (OCH?CH?O) is favored energetically on the Ni/Pt catalyst. Temperature-programmed desorption (TPD) experiments were conducted with deuterated ethylene glycols for comparison with DFT results. These experiments confirmed that decomposition of ethylene glycol on Pt proceeds via initial O–H bond cleavage, followed by C–H and the second O–H bond cleavages, whereas on the Ni/Pt surface, both O–H bonds are cleaved initially. The results are consistent with vibrational spectra and indicate that tuning of the catalyst surface can selectively control bond breaking. Finally, the significant mechanistic differences in decomposition of polyols compared to that of monoalcohols and hydrocarbons serve to identify general trends in bond scission sequences.

  17. Interplay between out-of-plane anisotropic L1{sub 1}-type CoPt and in-plane anisotropic NiFe layers in CoPt/NiFe exchange springs

    SciTech Connect (OSTI)

    Saravanan, P. [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); Hsu, Jen-Hwa, E-mail: jhhsu@phys.ntu.edu.tw; Tsai, C. L. [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Tsai, C. Y.; Lin, Y. H. [Graduate Institute of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan (China); Kuo, C. Y.; Wu, J.-C. [Department of Physics, National Chang Hua University of Education, Chang Hua 50000, Taiwan (China); Lee, C.-M. [Graduate School of Materials Science, National Yunlin University of Science and Technology, Douliou 64002, Taiwan (China)

    2014-06-28T23:59:59.000Z

    Films of L1{sub 1}-type CoPt/NiFe exchange springs were grown with different NiFe (Permalloy) layer thickness (t{sub NiFe}?=?0–10?nm). X-ray diffraction analysis reveals that the characteristic peak position of NiFe(111) is not affected by the CoPt-layer—confirming the absence of any inter-diffusion between the CoPt and NiFe layers. Magnetic studies indicate that the magnetization orientation of NiFe layer can be tuned through varying t{sub NiFe} and the perpendicular magnetic anisotropy of L1{sub 1}-type CoPt/NiFe films cannot sustain for t{sub NiFe} larger than 3.0?nm due to the existence of exchange interaction at the interface of L1{sub 1}-CoPt and NiFe layers. Magnetic force microscopy analysis on the as-grown samples shows the changes in morphology from maze-like domains with good contrast to hazy domains when t{sub NiFe}???3.0?nm. The three-dimensional micro-magnetic simulation results demonstrate that the magnetization orientation in NiFe layer is not uniform, which continuously increases from the interface to the top of NiFe layer. Furthermore, the tilt angle of the topmost NiFe layers can be changed over a very wide range from a small number to about 75° by varying t{sub NiFe} from 1 to 10?nm. It is worth noting that there is an abrupt change in the magnetization direction at the interface, for all the t{sub NiFe} investigated. The results of present study demonstrate that the tunable tilted exchange springs can be realized with L1{sub 1}-type CoPt/NiFe bilayers for future applications in three-axis magnetic sensors or advanced spintronic devices demanding inclined magnetic anisotropy.

  18. Phase formation and morphological stability of ultrathin Ni-Co-Pt silicide films formed on Si(100)

    SciTech Connect (OSTI)

    Xu, Peng; Wu, Dongping, E-mail: dongpingwu@fudan.edu.cn [State Key Laboratory of ASIC and System, Fudan University, Shanghai 200433 (China); Kubart, Tomas; Gao, Xindong [Solid-State Electronics, The Ångström Laboratory, Uppsala University, P.O. Box 534, 75121 Uppsala (Sweden); Zhang, Shi-Li, E-mail: shili.zhang@angstrom.uu.se [State Key Laboratory of ASIC and System, Fudan University, Shanghai 200433, China and Solid-State Electronics, The Ångström Laboratory, Uppsala University, P.O. Box 534, 75121 Uppsala (Sweden)

    2014-05-15T23:59:59.000Z

    Ultrathin Ni, Co, and Pt films, each no more than 4?nm in thickness, as well as their various combinations are employed to investigate the competing growth of epitaxial Co{sub 1-y}Ni{sub y}Si{sub 2} films against polycrystalline Pt{sub 1-z}Ni{sub z}Si. The phase formation critically affects the morphological stability of the resulting silicide films, with the epitaxial films being superior to the polycrystalline ones. Any combination of those metals improves the morphological stability with reference to their parent individual metal silicide films. When Ni, Co, and Pt are all included, the precise initial location of Pt does little to affect the final phase formation in the silicide films and the epitaxial growth of Co{sub 1-x}Ni{sub x}Si{sub 2} films is always perturbed, in accordance to thermodynamics that shows a preferential formation of Pt{sub 1-z}Ni{sub z}Si over that of Co{sub 1-y}Ni{sub y}Si{sub 2}.

  19. The morphology of electroless Ni deposition on a colloidal Pd(II) catalyst

    SciTech Connect (OSTI)

    Brandow, S.L.; Dressick, W.J.; Marrian, C.R.K.; Chow, G.M.; Calvert, J.M. [Naval Research Laboratory, Washington, DC (United States)

    1995-07-01T23:59:59.000Z

    The surface morphology of a surface-bound colloidal Pd(II) catalyst and its effect on the particle sizes with the largest particles reaching approximately 50 nm in diameter. Catalyst surface coverages as low as 20% are found to be sufficient to initiate complete and homogeneous metallization. The distribution of particle sizes for the electroless metal deposit, found to be a function of plating time, is broad with the maximum Ni particle size exceeding 120 nm. Results indicate controlling the size of the bound catalyst is the principal determining factor in controlling the particle size of the electroless deposit. Modification of the surface by depleting the concentration of surface functional groups capable of binding catalyst is used to shift the size distribution of bound catalyst to smaller values. A resulting three-to fourfold reduction in the particle size of the electroless deposit is demonstrated.

  20. Well-defined ultrathin Pd films on Pt(111): electrochemical preparation and interfacial chemistry

    E-Print Network [OSTI]

    Park, Yeon Su

    2005-08-29T23:59:59.000Z

    . In both methods, between the coverage regimes studied, the growth of the Pd films follows the Stranski-Krastanov mechanism. The interfacial electrochemical properties associated with the film-to-bulk transition were characterized by conventional...

  1. Time-domain detection of current controlled magnetization damping in Pt/Ni{sub 81}Fe{sub 19} bilayer and determination of Pt spin Hall angle

    SciTech Connect (OSTI)

    Ganguly, A.; Haldar, A.; Sinha, J.; Barman, A., E-mail: abarman@bose.res.in, E-mail: del.atkinson@durham.ac.uk [Thematic Unit of Excellence on Nanodevice Technology, Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata 700098 (India); Rowan-Robinson, R. M.; Jaiswal, S.; Hindmarch, A. T.; Atkinson, D. A., E-mail: abarman@bose.res.in, E-mail: del.atkinson@durham.ac.uk [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)

    2014-09-15T23:59:59.000Z

    The effect of spin torque from the spin Hall effect in Pt/Ni{sub 81}Fe{sub 19} rectangular bilayer film was investigated using time-resolved magneto-optical Kerr microscopy. Current flow through the stack resulted in a linear variation of effective damping up to ±7%, attributed to spin current injection from the Pt into the Ni{sub 81}Fe{sub 19}. The spin Hall angle of Pt was estimated as 0.11?±?0.03. The modulation of the damping depended on the angle between the current and the bias magnetic field. These results demonstrate the importance of optical detection of precessional magnetization dynamics for studying spin transfer torque due to spin Hall effect.

  2. Oxidation of Methanol on 2nd and 3rd Row Group VIII Transition Metals (Pt, Ir, Os, Pd, Rh, and Ru): Application to Direct Methanol

    E-Print Network [OSTI]

    Goddard III, William A.

    Oxidation of Methanol on 2nd and 3rd Row Group VIII Transition Metals (Pt, Ir, Os, Pd, Rh, and Ru): Application to Direct Methanol Fuel Cells Jeremy Kua and William A. Goddard III* Contribution from functional theory (B3LYP)], we calculated the 13 most likely intermediate species for methanol oxidation

  3. High Temperature Oxidation Behavior of gamma-Ni+gamma'-Ni3Al Alloys and Coatings Modified with Pt and Reactive Elements

    SciTech Connect (OSTI)

    Nan Mu

    2007-12-01T23:59:59.000Z

    Materials for high-pressure turbine blades must be able to operate in the high-temperature gases (above 1000 C) emerging from the combustion chamber. Accordingly, the development of nickel-based superalloys has been constantly motivated by the need to have improved engine efficiency, reliability and service lifetime under the harsh conditions imposed by the turbine environment. However, the melting point of nickel (1455 C) provides a natural ceiling for the temperature capability of nickel-based superalloys. Thus, surface-engineered turbine components with modified diffusion coatings and overlay coatings are used. Theses coatings are capable of forming a compact and adherent oxide scale, which greatly impedes the further transport of reactants between the high-temperature gases and the underlying metal and thus reducing attack by the atmosphere. Typically, these coatings contain {beta}-NiAl as a principal constituent phase in order to have sufficient aluminum content to form an Al{sub 2}O{sub 3} scale at elevated temperatures. The drawbacks to the currently-used {beta}-based coatings, such as phase instabilities, associated stresses induced by such phase instabilities, and extensive coating/substrate interdiffusion, are major motivations in this study to seek next-generation coatings. The high-temperature oxidation resistance of novel Pt + Hf-modified {gamma}-Ni + {gamma}-Ni{sub 3}Al-based alloys and coatings were investigated in this study. Both early-stage and 4-days isothermal oxidation behavior of single-phase {gamma}-Ni and {gamma}{prime}-Ni{sub 3}Al alloys were assessed by examining the weight changes, oxide-scale structures, and elemental concentration profiles through the scales and subsurface alloy regions. It was found that Pt promotes Al{sub 2}O{sub 3} formation by suppressing the NiO growth on both {gamma}-Ni and {gamma}{prime}Ni{sub 3}Al single-phase alloys. This effect increases with increasing Pt content. Moreover, Pt exhibits this effect even at lower temperatures ({approx}970 C) in the very early stage of oxidation. It was also inferred that Pt enhances the diffusive flux of aluminum from the substrate to the scale/alloy interface. Relatively low levels of hafnium addition to Pt-free {gamma}{prime}-Ni{sub 3}Al increased the extent of external NiO formation due to non-protective HfO{sub 2} formation. Accordingly, this effect intensified with increasing Hf content from 0.2 to 0.5 at.%.

  4. Middle distillate hydrotreatment zeolite catalysts containing Pt/Pd or Ni 

    E-Print Network [OSTI]

    Marin-Rosas, Celia

    2009-05-15T23:59:59.000Z

    showing part of the peaks with retention times in the interval of 114-121 min. ????????????????????? 110 5.11 Fluorene hydrogenation network (From Lapinas et al., (1991)). ?. 112 xx FIGURE Page 5.12 Part of the total ion chromatogram... of a typical HDS product and the HGO showing the peaks of the reaction products of HDS of DBT??.??????????????????????.. 113 5.13 Part of the total ion chromatogram of a typical HDS product and the HGO showing the peaks of fluorene...

  5. Shape memory behavior of ultrafine grained NiTi and TiNiPd shape memory alloys

    E-Print Network [OSTI]

    Kockar, Benat

    2009-05-15T23:59:59.000Z

    The cyclic instability in shape memory characteristics of NiTi-based shape memory alloys (SMAs), such as transformation temperatures, transformation and irrecoverable strains and transformation hysteresis upon thermal and mechanical cycling limits...

  6. Relativistic MR-MP calculations of the energy levels and transition probabilities in Ni- to Kr-like Pt ions

    SciTech Connect (OSTI)

    Santana, Juan A., E-mail: santanajuan@berkeley.edu [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450 (United States); Department of Chemistry, University of Puerto Rico, P.O. Box 23346, San Juan, PR 00931 (United States); Ishikawa, Yasuyuki, E-mail: yishikawa@uprrp.edu [Department of Chemistry, University of Puerto Rico, P.O. Box 23346, San Juan, PR 00931 (United States)] [Department of Chemistry, University of Puerto Rico, P.O. Box 23346, San Juan, PR 00931 (United States); Träbert, Elmar, E-mail: traebert@astro.rub.de [Astronomisches Institut, Ruhr-Universität Bochum, D-44780 Bochum (Germany) [Astronomisches Institut, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Physics Division, LLNL, P.O. Box 808, Livermore, CA 94551 (United States)

    2014-01-15T23:59:59.000Z

    Ni- to Kr-like Pt ions have been studied by relativistic multi-reference Møller–Plesset many-body perturbation theory calculations. Energy levels and lifetimes of low-lying excited states within the n=4 complex are reported for each ion. Wavelengths and transition probabilities for the strongest electric-dipole transitions are compared with available experimental data. Synthetic radiative spectra are shown for various wavelength regions.

  7. Effects of temperature dependent pre-amorphization implantation on NiPt silicide formation and thermal stability on Si(100)

    SciTech Connect (OSTI)

    Ozcan, Ahmet S.; Wall, Donald [IBM Semiconductor Research and Development Center, 2070 Route 52, Hopewell Junction, New York 12533 (United States)] [IBM Semiconductor Research and Development Center, 2070 Route 52, Hopewell Junction, New York 12533 (United States); Jordan-Sweet, Jean; Lavoie, Christian [IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598 (United States)] [IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598 (United States)

    2013-04-29T23:59:59.000Z

    Using temperature controlled Si and C ion implantation, we studied the effects of pre-amorphization implantation on NiPt alloy silicide phase formation. In situ synchrotron x-ray diffraction and resistance measurements were used to monitor phase and morphology evolution in silicide films. Results show that substrate amorphization strongly modulate the nucleation of silicide phases, regardless of implant species. However, morphological stability of the thin films is mainly enhanced by C addition, independently of the amorphization depth.

  8. Shape memory behavior of ultrafine grained NiTi and TiNiPd shape memory alloys 

    E-Print Network [OSTI]

    Kockar, Benat

    2009-05-15T23:59:59.000Z

    , (b) SAD pattern taken from the circled area in (a) showing the >compound twinning and )001( }111{ ? Type I twinning, respectively...... 59... martensite, respectively .................................................... 63 SIM ? M y Figure 4.9 Monotonic mechanical response of the hot rolled and ECAE processed Ni 49.7 Ti 50.3 samples under tension at to be thermodynamically same condition...

  9. High performance of a carbon supported ternary PdIrNi catalyst for ethanol electro-oxidation in anion-exchange membrane direct ethanol fuel cells

    E-Print Network [OSTI]

    Zhao, Tianshou

    -oxidation in anion-exchange membrane direct ethanol fuel cells Shuiyun Shen, T. S. Zhao,* Jianbo Xu and Yinshi Li-exchange membrane direct ethanol fuel cells (AEM DEFCs). We demonstrate that the use of the ternary PdIrNi catalyst for the ethanol oxidation reaction (EOR) in anion-exchange membrane direct ethanol fuel cells (AEM DEFCs) offers

  10. Photoelectron spectroscopy of nickel group dimers: Ni:, PdF, and Ptc Joe Ho,`) Mark L. Polak,b) Kent M. Ervin,C) and W. C. Lineberger

    E-Print Network [OSTI]

    Lineberger, W. Carl

    Photoelectron spectroscopy of nickel group dimers: Ni:, PdF, and Ptc Joe Ho,`) Mark L. Polak are tentatively assigned.Comparison of the nickel group dimers to the coinage metal dimers shedslight on the d orbital contribution to the metal bonding in the nickel group dimers. I. INTRODUCTION Spectroscopicstudy

  11. Suppression of the spin pumping in Pd/Ni{sub 81}Fe{sub 19} bilayers with nano-oxide layer

    SciTech Connect (OSTI)

    Kim, Duck-Ho; Kim, Hong-Hyoun; You, Chun-Yeol [Department of Physics, Inha University, Namgu Incheon 402-751 (Korea, Republic of)

    2011-08-15T23:59:59.000Z

    We demonstrate that the spin pumping effect can be effectively suppressed with a nano-oxide layer. Spin pumping effect manifests itself by an enhancement of the Gilbert damping parameter in normal metal/ferromagnetic hetero-structures, while many spintronics devices prefer smaller damping parameter. Since the spin pumping effect is directly related with the spin dependent interface conductance, we can modify the spin pumping by altering the interface conductance with the nano-oxide layer. We prepared series of Pd/Ni{sub 81}Fe{sub 19} bilayers with different pausing time between Pd and Ni{sub 81}Fe{sub 19} depositions in order to control the interface conductance. The Gilbert damping parameters are determined from the line-width measurements in the ferromagnetic resonance spectra for each pausing time sample. They are 0.0490, 0.0296, 0.0278, and 0.0251 for 0, 6, 30, and 60 s pausing time, respectively. We find that the damping parameter of Pd/Ni{sub 81}Fe{sub 19} is almost recovered to one of the Cu/Ni{sub 81}Fe{sub 19} bilayer with 60 s pausing time, while the static magnetic properties are not noticeably changed.

  12. Mechanisms Associated with Rumpling of Pt-Modified Beta-NiAl Coatings

    SciTech Connect (OSTI)

    Joseph Peter Henderkott

    2007-12-01T23:59:59.000Z

    The formation of surface undulations (i.e. rumpling) at the bond coat/thermally grown oxide (TGO) interface has been shown to cause failure by spallation of the ceramic top coat in aero-turbine systems. Many mechanisms have been proposed concerning the cause of these surface distortions; however, there is little agreement on what may be the dominating cause of the rumpling behavior. Of there mechanisms, the reversible phase transformation from a cubic {beta}-NiAl structure to a face centered tetragonal (FCT) martensitic phase was of particular interest because of its ability to form surface rumpling in Pt-modified {beta} bulk alloys. However, the bulk alloys used in obtaining that result were simple ternary systems and not relevant to actual coating compositions as other alloying elements enter the coating due to coating/substrate interdiffusion at high temperature. In the current study, the depletion behavior of a commercial coating was studied. Compositions from the depletion path were determined and bulk alloys representing these coating compositions were prepared. The martensitic phase transformation was then characterized using DSC and XRD. The martensitic start temperature on cooling, Ms, was consistently found to be significantly lower than previously reported values (e.g. 530 C vs 100 C). Because of the low Ms temperature, the formation of the martensitic phase was concluded to be unnecessary for the occurrence of rumpling. However, cyclic exposure treatments at low temperature ({approx} 400 C) of bulk alloys and commercial coatings did show the detrimental effects of the phase transformation in the form of crack formation and propagation leading to eventual failure of the alloys. The current work also infers that the differences in coefficient of thermal expansion (CTE) mismatch between the coating and substrate are the dominating factor leading to rumpling. Dilatometry measurements were made on bulk alloys representing depleted coatings and the superalloy substrate to determine CTE as a function of temperature. Finally, simulations were completed to help determine the role of CTE mismatch. It was found that these results compared closely to those collected during experimental cyclic exposure treatments; although, modification to the current model were found to be needed in order to truly simulate rumpling.

  13. Systematics of the temperature-dependent interplane resistivity in Ba(Fe1-xMx)?As? (M=Co, Rh, Ni, and Pd)

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

    Tanatar, M. A.; Ni, N.; Thaler, A.; Bud’ko, S. L.; Canfield, P. C.; Prozorov, R.

    2011-07-01T23:59:59.000Z

    Temperature-dependent interplane resistivity ?c(T) was measured systematically as a function of transition-metal substitution in the iron-arsenide superconductors Ba(Fe1-xMx)?As?, M=Ni, Pd, Rh. The data are compared with the behavior found in Ba(Fe1-xCox)?As?, revealing resistive signatures of pseudogap. In all compounds we find resistivity crossover at a characteristic pseudogap temperature T* from nonmetallic to metallic temperature dependence on cooling. Suppression of T* proceeds very similarly in cases of Ni and Pd doping and much faster than in similar cases of Co and Rh doping. In cases of Co and Rh doping an additional minimum in the temperature-dependent ?c emerges for high dopings, when superconductivity is completely suppressed. These features are consistent with the existence of a charge gap covering part of the Fermi surface. The part of the Fermi surface affected by this gap is notably larger for Ni- and Pd-doped compositions than in Co- and Rh-doped compounds.

  14. Large exchange bias enhancement in (Pt(or Pd)/Co)/IrMn/Co trilayers with ultrathin IrMn thanks to interfacial Cu dusting

    SciTech Connect (OSTI)

    Vinai, G. [SPINTEC, UMR 8191 CEA/CNRS/UJF/Grenoble-INP, CEA/INAC, 17, rue des Martyrs, 38054 Grenoble (France); Crocus Technology, 4 Place Robert Schuman, 38054 Grenoble (France); Moritz, J. [Institut Jean Lamour, UMR 7198 CNRS - Université de Lorraine, Bd des Aiguillettes, BP 70239, F-54506 Vandoeuvre-les-Nancy Cedex (France); Bandiera, S. [Crocus Technology, 4 Place Robert Schuman, 38054 Grenoble (France); Prejbeanu, I. L.; Dieny, B. [SPINTEC, UMR 8191 CEA/CNRS/UJF/Grenoble-INP, CEA/INAC, 17, rue des Martyrs, 38054 Grenoble (France)

    2014-04-21T23:59:59.000Z

    The magnitude of exchange bias (H{sub ex}) at room temperature can be significantly enhanced in IrMn/Co and (Pt(or Pd)/Co)/IrMn/Co structures thanks to the insertion of an ultrathin Cu dusting layer at the IrMn/Co interface. The combination of trilayer structure and interfacial Cu dusting leads to a three-fold increase in H{sub ex} as compared to the conventional IrMn/Co bilayer structure, with an increased blocking temperature (T{sub B}) and a concave curvature of the temperature dependence H{sub ex}(T), ideal for improved Thermally Assisted-Magnetic Random Access Memory storage layer. This exchange bias enhancement is ascribed to a reduction of the spin frustration at the IrMn/Co interface thanks to interfacial Cu addition.

  15. The effect of Au and Ni doping on the heavy fermion state of the Kondo lattice antiferromagnet CePtZn

    SciTech Connect (OSTI)

    Dhar, S. K., E-mail: sudesh@tifr.res.in [DCMPMS, T.I.F.R., Homi Bhabha Road, Colaba, Mumbai 400005 (India); Aoki, Y.; Suemitsu, B.; Miyazaki, R. [Department of Physics, Tokyo Metropolitan University, Minami-Ohsawa 1-1, Hachioji-Shi, Tokyo (Japan); Provino, A.; Manfrinetti, P. [Departimento Physica Chemicale, Universita di Genova, Via Dodecaneso, 16146 Genova (Italy)

    2014-05-07T23:59:59.000Z

    We have probed the effect of doping CePtZn with Au and Ni and also investigated in detail the magnetic behavior of the iso-structural CeAuZn. A magnetic ground state is observed in both CePt{sub 0.9}Au{sub 0.1}Zn and CePt{sub 0.9}Ni{sub 0.1}Zn with T{sub N}?=?2.1 and 1.1?K and the coefficient of the linear term of electronic heat capacity ??=?0.34 and 0.9?J/mol K{sup 2}, respectively. The corresponding values for CePtZn are 1.7?K and 0.6?J/mol K{sup 2}. The altered values of T{sub N} and ? show that the electronic correlations in CePtZn are affected by doping with Au and Ni. CeAuZn orders magnetically near 1.7?K and its electrical resistivity shows a normal metallic behavior. Together with a ? of 0.022?J/mol K{sup 2} the data indicate a weak 4f-conduction electron hybridization in CeAuZn characteristic of normal trivalent cerium based systems.

  16. Dppm-Assisted synthesis and reactivity of bimetallic M-Mo, M-W, M-Co, and M-Mn (M = Pt, Pd) complexes. Crystal structure of [([eta][sup 2]-dppm)[ovr Pt([mu]-dppm)W](CO)[sub 2]Cp][PF[sub 6

    SciTech Connect (OSTI)

    Braunstein, P.; de Meric de Bellefon, C.; Oswald, B.; Ries, M. (Universite Louis Pasteur, Strasbourg (France)); Lanfranchi, M.; Tiripicchio, A. (Universita di Parma (Italy))

    1993-04-28T23:59:59.000Z

    Heterometallic carbonyl complexes and clusters were prepared by reaction of dppm (dppm = Ph[sub 2]PCH[sub 2]PPh[sub 2]) with linear trinuclear chain complexes trans-[Pt(or Pd)[l brace]m(CO)[r brace][sub 2](NCPh)[sub 2

  17. Catalyst and process development for hydrogen preparation from future fuel cell feedstocks. Quarterly progress report, October 1, 1979-December 31, 1979. [Pt/Rh, Ni/Rh, Ni/Pt/Rh, Ni, Ni/Ru, Ni/Pt, Ni/Co

    SciTech Connect (OSTI)

    Yarrington, R M; Feins, I R; Hwang, H S; Mayer, C P

    1980-01-01T23:59:59.000Z

    Twelve steam reforming catalysts were evaluated using an autothermal reforming screening unit. Duplicate tests were run with two samples to determine test variability. The samples tested contained either base metals, precious metals, or combinations of base and precious metals. The test was capable of distinguishing among samples where gross variations in composition are the main factor; for example, catalysts containing 2% by weight precious metals are more active than catalysts containing 15% by weight nickel. The results show a decrease in hydrocarbon breakthrough as the weight of nickel charged to the constant volume reactor increases. A commercial nickel catalyst, G90C, appears slightly better than some Engelhard prepared samples of equal nickel concentrations due to the higher density of G90C. Visual observation of the used catalysts show that samples containing only precious metals (Pt/Rh) did not coke during the run. The samples containing only base metals (nickel, cobalt) were coked and were magnetic. Samples containing 14.5% nickel by weight with 0.5% precious metals by weight added were not coked, were not magnetic, and had a blue colored core as compared to the black core of the virgin samples. Some speculation about deactivation mechanisms based on these observations are made.

  18. Chemisorption of atomic oxygen on Pt(1 1 1) and Pt/Ni(1 1 1) surfaces Timo Jacob, Boris V. Merinov, William A. Goddard III *

    E-Print Network [OSTI]

    Goddard III, William A.

    at electrodes provides a significant opportunity for im- proving fuel cell performance. To make progress. Nowadays in PEM fuel cells Pt and Pt-based mate- rials are commonly used to catalyze the reactions Elsevier B.V. All rights reserved. 1. Introduction Optimization of the electro-catalytic processes

  19. Surface tension-driven shape-recovery of micro/nanometer-scale surface features in a Pt(57.5)Ni(5.3)Cu(14.7)P(22.5) metallic glass in the supercooled liquid region: A numerical modeling capability

    E-Print Network [OSTI]

    Henann, David Lee

    Recent experiments in the literature show that micro/nano-scale features imprinted in a Pt-based metallic glass, Pt57.5Ni5.3Cu14.7P22.5 [Pt subscript 57.5 Ni subscript 5.3 Cu subscript 14.7 P subscript 22.5], using ...

  20. The adhesion of electroless Ni(P) on alumina ceramic using a vacuum-deposited Ti-Pd activator layer

    SciTech Connect (OSTI)

    Severin, J.W.; Hokke, R.; Wel, H. van der; Johnson, M.T.; With, G. de (Philips Research Labs., Eindhoven (Netherlands))

    1993-06-01T23:59:59.000Z

    The adhesion of electrolessly deposited nickel on Al[sub 2]O[sub 3] ceramic substrates using sputtered and evaporated Ti-Pd activator films was studied. The adhesion was measured using the direct pull-off test and the 90[degree] peel test. The morphology and the chemical composition of the fracture surfaces of the samples with evaporated Ti-Pd activator film were studied with scanning electron microscopy/energy, dispersive x-ray, and static secondary ion mass spectroscopy. Failure did not occur along the metal-ceramic interface, but mainly in the alumina, and therefore the strength of the system is determined primarily by the substrate material. Cross-sectional transmission electron microscopy and high-resolution transmission electron microscopy were used to study the interface structure before failure. The oxidation state of Ti at the interface was measured with X-ray photoelectron spectroscopy. This was carried out in the (sub)monolayer range by using a Ti wedge deposited on alumina with a maximum thickness of 0.35 nm. It is concluded that the strong adhesion at the metal-ceramic interface is caused by chemical bonding of the first Ti monolayer with substrate oxygen atoms.

  1. Quantum Critical Fluctuations in the Heavy fermion compound Ce(Ni0.935Pd0.065)2Ge2

    SciTech Connect (OSTI)

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

    2014-12-01T23:59:59.000Z

    Electric resistivity, specific heat, magnetic susceptibility, and inelastic neutron scattering experi- ments were performed on a single crystal of the heavy fermion compound Ce(Ni0.935Pd0.065)2Ge2 in order to study the spin fluctuations near an antiferromagnetic (AF) quantum critical point (QCP). The resistivity and the specific heat coefficient for T = 1 K exhibit the power law behavior expected for a 3D itinerant AF QCP (?(T) ~ T^3/2 and ?(T) ~ ?0 -bT^1/2). However, for 2 = T = 10 K, the susceptibility and specific heat vary as logT and the resistivity varies linearly with temperature. Furthermore, despite the fact that the resistivity and specific heat exhibit the non-Fermi liquid behavior expected at a QCP, the correlation length, correlation time, and staggered susceptibility of the spin fluctuations remain finite at low temperature. We suggest that these deviations from the divergent behavior expected for a QCP may result from alloy disorder.

  2. Kinetic Characterization of PtRu Fuel Cell Anode Catalysts Made by Spontaneous Pt Deposition on Ru Nanoparticles

    E-Print Network [OSTI]

    Brankovic, Stanko R.

    rotating disk electrode without using Nafion film to stabilize them. Nonlinear fittings of the entire for a polycrystalline Pt electrode. For the PtRu20 , PtRu10 , and PtRu5 samples prepared by spontaneous deposition of 1 spontaneous deposition of Pt4 and Pd5 on Ru-single crystals, which facilitates a new method

  3. Catalyst and process development for hydrogen preparation from future fuel cell feedstocks. Quarterly report, April 1-June 30, 1980. [Pt/Pd

    SciTech Connect (OSTI)

    Yarrington, R M; Feins, I R; Hwang, H S

    1980-07-01T23:59:59.000Z

    Phase II of the contract, which involved catalyst preparation and evaluation, was nearly completed this quarter. Phase III, which calls for the design and construction of a fuel processor, was started. During the quarter, four types of tests were run on the small scale catalyst screening unit. The operating line for coke-free operations was found to be approximately between 0.41 to 0.44 O/sub 2//C level. Screening at lower O/sub 2//C levels led to problems with plugging. In other tests, increased severity for screening steam reforming catalysts was obtained by doubling the space velocity. Another series of tests were run to determine the gas composition from the catalytic partial oxidation (CPO) section and to evaluate two CPO catalysts. In the other series of tests, catalysts were aged for about 20 hours using a propane, steam, and air mixture before testing with No. 2 oil for another five hours. This latter test has been used to study Pt/Rh catalysts made with various supports. Differences were readily determined for Pt/Rh supported on alpha alumina and Pt/Rh supported on stabilized alumina. This test method will find continued use in evaluating metal-support interactions. Several samples must be evaluated by this method before aging runs are made in the larger unit. After leaching alumina from a used Pt/Rh catalyst, the x-ray diffraction pattern showed the presence of a Pt-Rh alloy in the metal residue. Experiments were run to show that the alloy was formed in the reactor during testing and not during catalyst preparation. A larger version of the ATR reactor has been designed and major components are on order. Completion of the construction phase is scheduled for the next quarter.

  4. Durable pd-based alloy and hydrogen generation membrane thereof

    DOE Patents [OSTI]

    Benn, Raymond C. (Madison, CT); Opalka, Susanne M. (Glastonbury, CT); Vanderspurt, Thomas Henry (Glastonbury, CT)

    2010-02-02T23:59:59.000Z

    A durable Pd-based alloy is used for a H.sub.2-selective membrane in a hydrogen generator, as in the fuel processor of a fuel cell plant. The Pd-based alloy includes Cu as a binary element, and further includes "X", where "X" comprises at least one metal from group "M" that is BCC and acts to stabilize the .beta. BCC phase for stability during operating temperatures. The metal from group "M" is selected from the group consisting of Fe, Cr, Nb, Ta, V, Mo, and W, with Nb and Ta being most preferred. "X" may further comprise at least one metal from a group "N" that is non-BCC, preferably FCC, that enhances other properties of the membrane, such as ductility. The metal from group "N" is selected from the group consisting of Ag, Au, Re, Ru, Rh, Y, Ce, Ni, Ir, Pt, Co, La and In. The at. % of Pd in the binary Pd--Cu alloy ranges from about 35 at. % to about 55 at. %, and the at. % of "X" in the higher order alloy, based on said binary alloy, is in the range of about 1 at. % to about 15 at. %. The metals are selected according to a novel process.

  5. Comparison of [Ni(PPh2NPh2)2(CH3CN)]2+ and [Pd(PPh2NPh2)2]2+ as Electrocatalysts for H2 Production

    SciTech Connect (OSTI)

    Wiedner, Eric S.; Helm, Monte L.

    2014-09-22T23:59:59.000Z

    The complexes [Ni(PPh2NPh2)2(CH3CN)]2+ and [Pd(PPh2NPh2)2]2+, where PPh2NPh2 is 1,5-diphenyl-3,7-diphenyl-1,5-diaza-3,7-diphosphacyclooctane, are compared as electrocatalysts for H2 production under identical experimental conditions. With [(DMF)H]+ as the acid in acetonitrile solution, [Pd(PPh2NPh2)2]2+ afforded a turnover frequency (TOF) of 230 s-1 for formation of H2 under dry conditions and a TOF of 640 s-1 when H2O was added. These rates are similar to the TOF’s of 590 s-1 (dry) and 720 s-1 (wet) that were previously measured for [Ni(PPh2NPh2)2(CH3CN)]2+ using [(DMF)H]+. The [Ni(PPh2NPh2)2(CH3CN)]2+ and [Pd(PPh2NPh2)2]2+ complexes both exhibited large current enhancements when treated with trifluoroacetic acid (TFA). At a TFA concentration of 1.8 M, TOF values of 5670 s-1 and 2060 s-1 were measured for [Ni(PPh2NPh2)2(CH3CN)]2+ and [Pd(PPh2NPh2)2]2+, respectively. The fast rates observed using TFA are, in part, attributed to homoconjugation of TFA in acetonitrile solutions, which decreases the effective pKa of the acid. In support of this hypothesis, dramatically lower rates of H2 production were observed using p anisidinium, which has a pKa comparable to TFA but does not homoconjugate significantly in acetonitrile solutions. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory is oper-ated by Battelle for the U.S. Department of Energy.

  6. Pull strength evaluation of Sn-Pb solder joints made to Au-Pt-Pd and Au thick film structures on low-temperature co-fired ceramic -final report for the MC4652 crypto-coded switch (W80).

    SciTech Connect (OSTI)

    Uribe, Fernando; Vianco, Paul Thomas; Zender, Gary L.

    2006-06-01T23:59:59.000Z

    A study was performed that examined the microstructure and mechanical properties of 63Sn-37Pb (wt.%, Sn-Pb) solder joints made to thick film layers on low-temperature co-fired (LTCC) substrates. The thick film layers were combinations of the Dupont{trademark} 4596 (Au-Pt-Pd) conductor and Dupont{trademark} 5742 (Au) conductor, the latter having been deposited between the 4596 layer and LTCC substrate. Single (1x) and triple (3x) thicknesses of the 4596 layer were evaluated. Three footprint sizes were evaluated of the 5742 thick film. The solder joints exhibited excellent solderability of both the copper (Cu) lead and thick film surface. In all test sample configurations, the 5742 thick film prevented side wall cracking of the vias. The pull strengths were in the range of 3.4-4.0 lbs, which were only slightly lower than historical values for alumina (Al{sub 2}O{sub 3}) substrates. General (qualitative) observations: (a) The pull strength was maximized when the total number of thick film layers was between two and three. Fewer that two layers did not develop as strong of a bond at the thick film/LTCC interface; more than three layers and of increased footprint area, developed higher residual stresses at the thick film/LTCC interface and in the underlying LTCC material that weakened the joint. (b) Minimizing the area of the weaker 4596/LTCC interface (e.g., larger 5742 area) improved pull strength. Specific observations: (a) In the presence of vias and the need for the 3x 4596 thick film, the preferred 4596:5742 ratio was 1.0:0.5. (b) For those LTCC components that require the 3x 4596 layer, but do not have vias, it is preferred to refrain from using the 5742 layer. (c) In the absence of vias, the highest strength was realized with a 1x thick 5742 layer, a 1x thick 4596 layer, and a footprint ratio of 1.0:1.0.

  7. An analysis of the pull strength behaviors of fine-pitch, flip chip solder interconnections using a Au-Pt-Pd thick film conductor on Low-Temperature, Co-fired Ceramic (LTCC) substrates.

    SciTech Connect (OSTI)

    Uribe, Fernando R.; Kilgo, Alice C.; Grazier, John Mark; Vianco, Paul Thomas; Zender, Gary L.; Hlava, Paul Frank; Rejent, Jerome Andrew

    2008-09-01T23:59:59.000Z

    The assembly of the BDYE detector requires the attachment of sixteen silicon (Si) processor dice (eight on the top side; eight on the bottom side) onto a low-temperature, co-fired ceramic (LTCC) substrate using 63Sn-37Pb (wt.%, Sn-Pb) in a double-reflow soldering process (nitrogen). There are 132 solder joints per die. The bond pads were gold-platinum-palladium (71Au-26Pt-3Pd, wt.%) thick film layers fired onto the LTCC in a post-process sequence. The pull strength and failure modes provided the quality metrics for the Sn-Pb solder joints. Pull strengths were measured in both the as-fabricated condition and after exposure to thermal cycling (-55/125 C; 15 min hold times; 20 cycles). Extremely low pull strengths--referred to as the low pull strength phenomenon--were observed intermittently throughout the product build, resulting in added program costs, schedule delays, and a long-term reliability concern for the detector. There was no statistically significant correlation between the low pull strength phenomenon and (1) the LTCC 'sub-floor' lot; (2) grit blasting the LTCC surfaces prior to the post-process steps; (3) the post-process parameters; (4) the conductor pad height (thickness); (5) the dice soldering assembly sequence; or (5) the dice pull test sequence. Formation of an intermetallic compound (IMC)/LTCC interface caused by thick film consumption during either the soldering process or by solid-state IMC formation was not directly responsible for the low-strength phenomenon. Metallographic cross sections of solder joints from dice that exhibited the low pull strength behavior, revealed the presence of a reaction layer resulting from an interaction between Sn from the molten Sn-Pb and the glassy phase at the TKN/LTCC interface. The thick film porosity did not contribute, explicitly, to the occurrence of reaction layer. Rather, the process of printing the very thin conductor pads was too sensitive to minor thixotropic changes to ink, which resulted in inconsistent proportions of metal and glassy phase particles present during the subsequent firing process. The consequences were subtle, intermittent changes to the thick film microstructure that gave rise to the reaction layer and, thus, the low pull strength phenomenon. A mitigation strategy would be the use of physical vapor deposition (PVD) techniques to create thin film bond pads; this is multi-chip module, deposited (MCM-D) technology.

  8. Surface Science Letters Spontaneous deposition of Pd on a Ru(0 0 0 1) surface

    E-Print Network [OSTI]

    Brankovic, Stanko R.

    deposition of Pd on a Pt(1 1 1) electrode, monolayer [3], or submonolayer [4,7] coverages were reportedSurface Science Letters Spontaneous deposition of Pd on a Ru(0 0 0 1) surface S.R. Brankovic, J. Mc March 2001 Abstract Spontaneous deposition of Pd on a Ru(0 0 0 1) single crystal surface has been

  9. Effect of Spin-Crossover-Induced Pore Contraction on CO{sub 2}-Host Interactions in the Porous Coordination Polymers [Fe(pyrazine)M(CN){sub 4}] (M = Ni, Pt)

    SciTech Connect (OSTI)

    Culp, Jeffrey T.; Chen, De-Li; Liu, Jinchen; Chirdon, Danielle; Kauffman, Kristi; Goodman, Angela; Johnson, J. Karl

    2013-02-01T23:59:59.000Z

    Variable-temperature in situ ATR-FTIR spectra are presented for the porous spin-crossover compounds [Fe(pyrazine)- Ni(CN){sub 4}] and [Fe(pyrazine)Pt(CN){sub 4}] under CO{sub 2} pressures of up to 8 bar. Significant shifts in the ?{sub 3} and ?{sub 2} IR absorption bands of adsorbed CO{sub 2} are observed as the host materials undergo transition between low- and high-spin states. Computational models used to determine the packing arrangement of CO{sub 2} within the pore structures show a preferred orientation of one of the adsorbed CO{sub 2} molecules with close O=C=O···H contacts with the pyrazine pillar ligands. The interaction is a consequence of the commensurate distance of the inter-pyrazine separations and the length of the CO{sub 2} molecule, which allows the adsorbed CO{sub 2} to effectively bridge the pyrazine pillars in the structure. The models were used to assign the distinct shifts in the IR absorption bands of the adsorbed CO{sub 2} that arise from changes in the O=C=O···H contacts that strengthen and weaken in correlation with changes in the Fe–N bond lengths as the spin state of Fe changes. The results indicate that spin-crossover compounds can function as a unique type of flexible sorbent in which the pore contractions associated with spin transition can affect the strength of CO{sub 2}–host interactions.

  10. CO oxidation trends on Pt-group metals from ultrahigh vacuum to near atmospheric pressures: A combined in situ PM-IRAS and reaction kinetics study

    E-Print Network [OSTI]

    Goodman, Wayne

    CO oxidation trends on Pt-group metals from ultrahigh vacuum to near atmospheric pressures Accepted for publication 14 October 2008 Available online 5 November 2008 Keywords: Pt-group metals CO a c t The CO oxidation reaction on Pt-group metals (Pt, Rh, and Pd) has been investigated at low (610À

  11. LEED crystallography studies of the structure of clean and adsorbate-covered Ir, Pt and Rh crystal surfaces

    SciTech Connect (OSTI)

    Koestner, R.J.

    1982-08-01T23:59:59.000Z

    There have only been a few Low Energy Electron Diffraction (LEED) intensity analyses carried out to determine the structure of molecules adsorbed on metal surfaces; most surface crystallography studies concentrated on the structure of clean unreconstructed or atomic adsorbate-covered transition metal faces. The few molecular adsorption systems already investigated by dynamical LEED are CO on Ni(100), Cu(100) and Pd(100) as well as C/sub 2/H/sub 2/ and C/sub 2/H/sub 4/ adsorbed on Pt(111). The emphasis of this thesis research has been to extend the applicability of LEED crystallography to the more complicated unit cells found in molecular overlayers on transition metals or in there constructed surfaces of clean transition metals.

  12. Self-assembled nano- to micron-size fibers from molten R11Ni4In9 intermetallics

    SciTech Connect (OSTI)

    Provino, Alessia; Manfrinetti, Pietro; Gschneidner, Karl A.; Dhar, Sudesh K.; Schlagel, Deborah L.; Lograsso, Thomas A.; Miller, Gordon J.; Thimmaiah, Srinivasa; Wang, Hui; Russell, Alan M.; Becker, Andrew; Mudryk, Yaroslav

    2014-07-01T23:59:59.000Z

    A study of the formation of Gd11M4In9 (M = Ni, Pd, Pt) and R11Ni4In9 (R = rare earth) compounds revealed a unique and peculiar property, which is to naturally crystallize in a bundle of self-assembled fibers when cooled from the melt. The fibers, which are nano- to millimeters in cross-section and approximate to 11-40 mm long, grow unidirectionally along a temperature gradient. These compounds adopt the orthorhombic Nd11Pd4In9 structure type (oC48-Cmmm). This structure is layered, with slabs of R atoms alternating with slabs of Ni/In atoms along a short c-axis (much shorter than either the a- or b-axis). The growth direction of the fibers is along the crystallographic c-axis, orthogonal to the a-b plane. Two strong and short In In bonds lie in the a-b plane, which are even shorter than in In metal. Integrated crystal orbital Hamilton population calculations show that the In In bonds create isolated "R8Ni4In9" rods growing along the c-axis, with the In In bonds being part of the rods. This appears to be an important factor explaining the microfibrous nature of these phases. Some physical properties have been measured on the Gd11Ni4In9 homolog. The compound orders ferrimagnetically at T-c approximate to 88 K, and at lower temperatures (46 and 10 K), two other magnetic anomalies were observed, probably due to spin reorientations. As expected from the bonding features, the mechanical, magnetic and electrical properties are strongly anisotropic. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  13. alloying ni yoru: Topics by E-print Network

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

    memory alloy Elastic modulus Wrinkling Thermoelastic strain in a polycrystalline Fe-Pd thin film 213 (X?1.5) Alloys 1 CiteSeer Summary: A series Ni41-xMn50Sn9+x of Heusler...

  14. alloy films ni: Topics by E-print Network

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

    memory alloy Elastic modulus Wrinkling Thermoelastic strain in a polycrystalline Fe-Pd thin film 22 Magnetic and Structural Properties of Ni-Mn-Ga Films Produced Via Physical...

  15. Investigation of the electrocatalysis for oxygen reduction reaction by Pt and binary Pt alloys: an XRD, XAS and electrochemical study

    SciTech Connect (OSTI)

    Mukerjee, S.; McBreen, J. [Brookhaven National Lab., Upton, NY (United States); Srinivasan, S. [Texas A and M Univ., College Station, TX (United States). Texas Engineering Experiment Station

    1995-12-31T23:59:59.000Z

    Electrocatalysis for the oxygen reduction reaction (ORR) on five binary Pt alloy electrocatalysts (PtCr/C, PtMn/C, PtFe/C, PtCo/C and PtNi/C) supported on carbon have been investigated. The electrochemical characteristics for ORR in a proton conducting fuel cell environment has been correlated with the electronic and structural parameters determined under in situ conditions using XANES and EXAFS technique respectively. Results indicate that all the alloys possess higher Pt 5d band vacancies as compared to Pt/C. There is also evidence of lattice contraction in the alloys (supported by XRD results). Further, the Pt/C shows increase in Pt 5 d band vacancies during potential transitions from 0.54 to 0.84 V vs. RHE, which has been ration@ on the basis of OH type adsorption. In contrast to this, the alloys do not exhibit such an enhancement. Detailed EXAFS analysis supports the presence of OH species on Pt/C and its relative absence in the alloys. Correlation of the electrochemical results with bond distances and d-band vacancies show a volcano type behavior with the PtCr/C on top of the curve.

  16. Fuel cell with Pt/Pd electrocatalyst electrode

    DOE Patents [OSTI]

    Stonehart, Paul (Madison, CT)

    1983-01-01T23:59:59.000Z

    An electrode for use in a phosphoric acid fuel cell comprising a graphitized or partially graphitized carbon support having a platinum/palladium electrocatalyst thereon. Preferably, the platinum/palladium catalyst comprises 20 to 65 weight percent palladium.

  17. Electrodeposition of ultrathin Pd, Co and Bi films on well-defined noble-metal electrodes: studies by ultrahigh vacuum-electrochemistry (UHV-EC) 

    E-Print Network [OSTI]

    Baricuatro, Jack Hess L

    2006-10-30T23:59:59.000Z

    Three illustrative cases involving the electrodeposition of ultrathin metal films of varying reactivities onto noble-metal substrates were investigated: (i) Pd on Pt(111), a noble admetal on a noble-metal surface; (ii) Bi ...

  18. Synthesis and characterization of Pd(0), PdS, and Pd-PdO core-shell nanoparticles by solventless thermolysis of a Pd-thiolate cluster

    SciTech Connect (OSTI)

    Jose, Deepa [Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012 (India); Jagirdar, Balaji R., E-mail: jagirdar@ipc.iisc.ernet.i [Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012 (India)

    2010-09-15T23:59:59.000Z

    Colloids of palladium nanoparticles have been prepared by the solvated metal atom dispersion (SMAD) method. The as-prepared Pd colloid consists of particles with an average diameter of 2.8{+-}0.1 nm. Digestive ripening of the as-prepared Pd colloid, a process involving refluxing the as-prepared colloid at or near the boiling point of the solvent in the presence of a passivating agent, dodecanethiol resulted in a previously reported Pd-thiolate cluster, [Pd(SC{sub 12}H{sub 25}){sub 2}]{sub 6} but did not render the expected narrowing down of the particle size distribution. Solventless thermolysis of the Pd-thiolate complex resulted in various Pd systems such as Pd(0), PdS, and Pd-PdO core-shell nanoparticles thus demonstrating its versatility. These Pd nanostructures have been characterized using high-resolution electron microscopy and powder X-ray diffraction methods. - Graphical abstract: Solventless thermolysis of a single palladium-thiolate cluster affords various Pd systems such as Pd(0), Pd-PdO core-shell, and PdS nanoparticles demonstrating the versatility of the precursor and the methodology.

  19. CO Oxidation on Pt-Group Metals from Ultrahigh Vacuum to Near Atmospheric Pressures. 2. Palladium and Platinum

    E-Print Network [OSTI]

    Goodman, Wayne

    CO Oxidation on Pt-Group Metals from Ultrahigh Vacuum to Near Atmospheric Pressures. 2. PalladiumVed: NoVember 3, 2008 CO oxidation on Pd(100), -(111), -(110), and Pt(110) single crystals was studied compositions. At low pressures the reaction fell into two regimes, one with a CO-dominant surface where the CO2

  20. Author's personal copy CO/NO and CO/NO/O2 reactions over a AuPd single crystal catalyst

    E-Print Network [OSTI]

    Goodman, Wayne

    Model catalyst CO oxidation NO reduction Surface segregation Polarization modulation Infrared reflection 0) model catalyst at near atmospheric pressures. The alloy catalyst exhibits higher CO2 formation of Pd- only TWCs is near that of Pt/Rh TWCs, it is preferred since Rh is not required. Moreover, Pd

  1. Carbon-Supported bimetallic Pd-Fe catalysts for vapor-phase hydrodeoxygenation of guaiacol

    SciTech Connect (OSTI)

    Sun, Junming; Karim, Ayman M.; Zhang, He; Kovarik, Libor; Li, Xiaohong S.; Hensley, Alyssa; McEwen, Jean-Sabin; Wang, Yong

    2013-10-01T23:59:59.000Z

    Abstract Carbon supported metal catalysts (Cu/C, Fe/C, Pd/C, Pt/C, PdFe/C and Ru/C) have been prepared, characterized and tested for vapor-phase hydrodeoxygenation (HDO) of guaiacol (GUA) at atmospheric pressure. Phenol was the major intermediate on all catalysts. Over the noble metal catalysts saturation of the aromatic ring was the major pathway observed at low temperature (250 °C), forming predominantly cyclohexanone and cyclohexanol. Substantial ring opening reaction was observed on Pt/C and Ru/C at higher reaction temperatures (e.g., 350 °C). Base metal catalysts, especially Fe/C, were found to exhibit high HDO activity without ring-saturation or ring-opening with the main products being benzene, phenol along with small amounts of cresol, toluene and trimethylbenzene (TMB). A substantial enhancement in HDO activity was observed on the PdFe/C catalysts. Compared with Fe/C, the yield to oxygen-free aromatic products (i.e., benzene/toluene/TMB) on PdFe/C increased by a factor of four at 350 °C, and by approximately a factor of two (83.2% versus 43.3%) at 450 °C. The enhanced activity of PdFe/C is attributed to the formation of PdFe alloy as evidenced by STEM, EDS and TPR.

  2. Pd/Ni-WO3 anodic double layer gasochromic device

    DOE Patents [OSTI]

    Lee, Se-Hee; Tracy, C. Edwin; Pitts, J. Roland; Liu, Ping

    2004-04-20T23:59:59.000Z

    An anodic double layer gasochromic sensor structure for optical detection of hydrogen in improved response time and with improved optical absorption real time constants, comprising: a glass substrate; a tungsten-doped nickel oxide layer coated on the glass substrate; and a palladium layer coated on the tungsten-doped nickel oxide layer.

  3. ALTERNATIVE MATERIALS TO PD MEMBRANES FOR HYDROGEN PURIFICATION

    SciTech Connect (OSTI)

    Korinko, P; T. Adams

    2008-09-12T23:59:59.000Z

    Development of advanced hydrogen separation membranes in support of hydrogen production processes such as coal gasification and as front end gas purifiers for fuel cell based system is paramount to the successful implementation of a national hydrogen economy. Current generation metallic hydrogen separation membranes are based on Pd-alloys. Although the technology has proven successful, at issue is the high cost of palladium. Evaluation of non-noble metal based dense metallic separation membranes is currently receiving national and international attention. The focal point of the reported work was to evaluate two different classes of materials for potential replacement of conventional Pd-alloy purification/diffuser membranes. Crystalline V-Ni-Ti and Amorphous Fe- and Co-based metallic glass alloys have been evaluated using gaseous hydrogen permeation testing techniques.

  4. JUNE 13-PD.xlsx

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

    No I-00516-0005 22-2&3-PD 083095 ISSUANCE OF MODIFICATION 9 TO KENTUCKY HAZARDOUS WASTE MANAGEMENT PERMIT - PGDP KDEP DOE-PAD, ERWM SITE MANAGER, BETHESDA MD, USEC No...

  5. High Pt Jet Physics

    E-Print Network [OSTI]

    M. Martinez

    2006-10-13T23:59:59.000Z

    In this contribution, a comprehensive review of the main aspects of high $\\pt$ jet physics in Run II at the Tevatron is presented. Recent measurements on inclusive jet production are discussed using different jet algorithms and covering a wide region of jet transverse momentum and jet rapidity. Several measurements, sensitive to a proper description of soft gluon radiation and the underlying event in hadron collisions, are shown. Finally, high $\\pt$ prompt photon measurements and studies on the production of electroweak bosons in association with jets in the final state are discussed.

  6. Highly durable graphene nanoplatelets supported Pt nanocatalysts...

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

    durable graphene nanoplatelets supported Pt nanocatalysts for oxygen reduction . Highly durable graphene nanoplatelets supported Pt nanocatalysts for oxygen reduction . Abstract:...

  7. August 2000 Z .Materials Letters 45 2000 128132

    E-Print Network [OSTI]

    Zheng, Yufeng

    . TiNiHf alloys exhibit better shape memory properties than other TiNiX Z .XsPt, Pd, Au, Zr and Ni­132 129 Fig. 1. Schematic illustration for the SME measurement in the bending test. electrode

  8. Interaction of CO with Surface PdZn Alloys. | EMSL

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

    with Surface PdZn Alloys. Interaction of CO with Surface PdZn Alloys. Abstract: The adsorption and bonding configuration of CO on clean and Zn-covered Pd(111) surfaces was studied...

  9. The formation of PdCx over Pd-based catalysts in vapor-phase vinyl acetate synthesis: does a PdAu alloy catalyst resist carbide formation?

    E-Print Network [OSTI]

    Goodman, Wayne

    a Pd­Au/SiO2 mixed-metal catalyst. XRD data show that PdCx was produced in the pure Pd catalysts after greater resistance to the formation of PdCx. The XRD and XPS data are consistent with formation of a Pd in a micro-reactor using online GC; before reaction the catalysts were pretreated (oxidized in a 20 m

  10. The wetting behavior of NiAl and NiPtAl on polycrystalline alumina

    E-Print Network [OSTI]

    Gauffier, Antoine

    2008-01-01T23:59:59.000Z

    alumina by nickel-aluminum alloys with or without platinumcompositions of nickel-aluminum alloys (with or without

  11. The wetting behavior of NiAl and NiPtAl on polycrystalline alumina

    E-Print Network [OSTI]

    Gauffier, Antoine

    2008-01-01T23:59:59.000Z

    experiments of alumina by nickel-aluminium alloys andnickel-aluminium-platinum alloys with the sessile drop

  12. ammonia oxidation pt pd rd: Topics by E-print Network

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

    research into controlling nanocrystal Castell, Martin 216 Energy Savings from Floating Head Pressure in Ammonia Refrigeration Systems Texas A&M University - TxSpace Summary:...

  13. Supporting Information Localized Pd Overgrowth on Cubic Pt Nanocrystals for Enhanced

    E-Print Network [OSTI]

    Yang, Peidong

    . For CO stripping experiments, CO gas (Praxair, 99.99%) was bubbled at an open circuit through 0.5 M H2SO4

  14. au-pt-pd thick film: Topics by E-print Network

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

    heatingcooling system. Calibrate the sample temperature. Measure the Tg of PS thin film - and compare an ellipsometer with an INSTEC heatingcooling stage so that...

  15. PT-Symmetric Talbot Effects

    E-Print Network [OSTI]

    Hamidreza Ramezani; D. N. Christodoulides; V. Kovanis; I. Vitebskiy; Tsampikos Kottos

    2012-09-11T23:59:59.000Z

    We show that complex PT-symmetric photonic lattices can lead to a new class of self-imaging Talbot effects. For this to occur, we find that the input field pattern, has to respect specific periodicities which are dictated by the symmetries of the system. While at the spontaneous PT-symmetry breaking point, the image revivals occur at Talbot lengths governed by the characteristics of the passive lattice, at the exact phase it depends on the gain and loss parameter thus allowing one to control the imaging process.

  16. Bulk Migration of Ni/NiO in Ni-YSZ during Reducing Conditions...

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

    of NiNiO in Ni-YSZ can potentially help to design a better solid oxide fuel cell (SOFC) anode. We have observed that extensive hydrogen reduction and methane steam reforming...

  17. THE EFFECT OF CO ON HYDROGEN PERMEATION THROUGH PD AND INTERNALLY OXIDIZED AND UN-OXIDIZED PD ALLOY MEMBRANES

    SciTech Connect (OSTI)

    Shanahan, K.; Flanagan, T.; Wang, D.

    2010-10-20T23:59:59.000Z

    The H permeation of internally oxidized Pd alloy membranes such as Pd-Al and Pd-Fe, but not Pd-Y alloys, is shown to be more resistant to inhibition by CO(g) as compared to Pd or un-oxidized Pd alloy membranes. The increased resistance to CO is found to be greater at 423 K than at 473 K or 523 K. In these experiments CO was pre-adsorbed onto the membranes and then CO-free H{sub 2} was introduced to initiate the H permeation.

  18. First-principles study of the Pd–Si system and Pd(001)/SiC(001) hetero-structure

    SciTech Connect (OSTI)

    Turchi, P.E.A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ivashchenko, V.I. [National Academy of Sciences of Ukraine (NASU), Kiev (Ukraine)

    2014-11-01T23:59:59.000Z

    First-principles molecular dynamics simulations of the Pd(001)/3C–SiC(001) nano-layered structure were carried out at different temperatures ranging from 300 to 2100 K. Various PdSi (Pnma, Fm3m, P6m2, Pm3m), Pd2Si (P6?2m, P63/mmc, P3m1, P3?1m) and Pd3Si (Pnma, P6322, Pm3m, I4/mmm) structures under pressure were studied to identify the structure of the Pd/Si and Pd/C interfaces in the Pd/SiC systems at high temperatures. It was found that a large atomic mixing at the Pd/Si interface occurred at 1500–1800 K, whereas the Pd/C interface remained sharp even at the highest temperature of 2100 K. At the Pd/C interface, voids and a graphite-like clustering were detected. Palladium and silicon atoms interact at the Pd/Si interface to mostly form C22-Pd2Si and D011-Pd3Si fragments, in agreement with experiment.

  19. Simultaneous deposition of Ni nanoparticles and wires on a tubular halloysite template: A novel metallized ceramic microstructure

    SciTech Connect (OSTI)

    Fu Yubin [Institute of Solid State Physics, China Academy of Sciences, Hefei 230031 (China) and Luoyang Ship Material Research Institute, Luoyang 471039 (China)]. E-mail: ffyybb725@vip.sina.com; Zhang Lide [Institute of Solid State Physics, China Academy of Sciences, Hefei 230031 (China)

    2005-11-15T23:59:59.000Z

    Tubular halloysite can be used as a template to fabricate a novel metallized ceramic microstructure through electroless plating. Reduction of Pd ions by methanol is conducted to initiate Ni plating. There is a simultaneous deposition of Ni nanoparticles on the outer surface and discontinuous wires in the lumen site of the halloysite template obtained. The different deposition could be caused by the different composition distribution of ferric oxide impurity in the wall due to the isomorphic substitution during the formation of halloysite template. Its magnetic property is mainly attributed to the Ni nanoparticles, not the wires. The metallized ceramic microstructure has the potential to be utilized as a novel magnetic material.

  20. Pd modified Au on carbon as an effective and durable catalyst for the direct oxidation of HMF to FDCA

    SciTech Connect (OSTI)

    Villa, Alberto [Universita di Milano, Italy; Schiavoni, Marco [University of Milan and INFN, Milano, Italy; Campisi, Sebastiano [University of Milan and INFN, Milano, Italy; Veith, Gabriel M [ORNL; Prati, Laura [Universita di Milano, Italy

    2013-01-01T23:59:59.000Z

    We show that the modification of a gold/carbon catalyst with Pt or Pd produces stable and recyclable catalysts for the selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA). This finding is a significant advance over current conversion technology because of the technological importance of FDCA. Indeed, FDCA has been identified as one of twelve potential building blocks for the production of value added chemicals derived from biosources.1 FDCA is a potential replacement source of terephthalic acid, the monomer presently used for the production of polyethylene terephthalate (PET) and derived from hydrocarbon sources.2

  1. PD Dr. Martin Stetter, Siemens AG 1 Das lineare Modell

    E-Print Network [OSTI]

    Popeea, Corneliu - Chair for Foundations of Software Reliability and Theoretical Computer Science

    PD Dr. Martin Stetter, Siemens AG 1 Das lineare Modell · Ausgangspunkt: Lineares Perceptron vorgegeben, werden nicht gelernt #12;PD Dr. Martin Stetter, Siemens AG 2 · Geschrieben als Regressionsmodell Regression: Lineares Modell #12;PD Dr. Martin Stetter, Siemens AG 3 · ML-Parameterschätzung des linearen

  2. Synthesis of Methanol and Dimethyl Ether from Syngas over Pd...

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

    Methanol and Dimethyl Ether from Syngas over PdZnOAl2O3 Catalysts. Synthesis of Methanol and Dimethyl Ether from Syngas over PdZnOAl2O3 Catalysts. Abstract: A PdZnOAl2O3...

  3. Ca{sub 2}Pd{sub 3}Ge, a new fully ordered ternary Laves phase structure

    SciTech Connect (OSTI)

    Doverbratt, Isa, E-mail: isa.doverbratt@polymat.lth.se [Centre for Analysis and Synthesis, Lund University, P.O. Box 124, 22100 Lund (Sweden); Ponou, Simeon; Lidin, Sven [Centre for Analysis and Synthesis, Lund University, P.O. Box 124, 22100 Lund (Sweden)

    2013-01-15T23:59:59.000Z

    The title compound, Ca{sub 2}Pd{sub 3}Ge, was prepared as a part of a systematic investigation of the Ca-Pd-Ge ternary phase diagram. The structure was determined and refined from single-crystal X-ray diffraction data. It is a new fully ordered ternary Laves phase with the space group R-3m, Z=3, a=5.6191 (5) A, c=12.1674 (7) A, wR{sub 2}=0.054 (all data) and is isostructural to Mg{sub 2}Ni{sub 3}Si (Noreus et al., 1985 [17]) but due to the larger size of all elements in Ca{sub 2}Pd{sub 3}Ge, the cell axes are approximately 10% longer. The compound may formally be considered as a Zintl compound, with [Pd{sub 3}Ge]{sup 4-} forming a poly-anionic network and divalent Ca cations located in truncated tetrahedral interstices. The electronic structure and chemical bonding of Ca{sub 2}Pd{sub 3}Ge is discussed in terms of LMTO band structure calculations and compared with CaPd{sub 2} (MgCu{sub 2}-type). - Graphical abstract: The title compound, Ca{sub 2}Pd{sub 3}Ge is a new fully ordered ternary Laves phase which may formally be considered as a Zintl compound, with [Pd{sub 3}Ge]{sup 4-} forming a poly-anionic network and divalent Ca cations located in truncated tetrahedral interstices. The structure is composed of Kagome net layers, consisting of Pd atoms only, which are stacked in an ABC sequence. Band structure calculations show that the Fermi level is located at a local minimum of the DOS (pseudo-gap) indicating that the charge is roughly optimized in the structure. Highlights: Black-Right-Pointing-Pointer Site specific segregation in a Laves phase that is also a Zintl phase. Black-Right-Pointing-Pointer Pseudo-gap at the Fermi level in a Laves phase. Black-Right-Pointing-Pointer Distorted Frank-Kasper polyhedron.

  4. PT-Rotations, PT-Spherical Harmonics and the PT-Hydrogen Atom

    E-Print Network [OSTI]

    Juan M. Romero; R. Bernal-Jaquez; O. Gonzalez-Gaxiola

    2010-01-11T23:59:59.000Z

    We have constructed a set of non-Hermitian operators that satisfy the commutation relations of the SO(3)-Lie algebra. It is shown that this operators generate rotations in the configuration space and not in the momentum space but in a modified non-Hermitian momentum space. This generators are related with a new type of spherical harmonics that result to be PT-orthonormal. Additionally, we have shown that this operators represent conserved quantities for a non-Hermitian Hamiltonian with an additional complex term. As a particular case, the solutions of the corresponding PT-Hydrogen atom that includes a complex term are obtained, and it is found that a non-Hermitian Runge-Lenz vector is a conserved quantity. In this way, we obtain a set of non-Hermitian operators that satisfy the SO(4)-Lie algebra.

  5. Direct Determination of the Ionization Energies of PtC, PtO, and PtO2 with VUVRadiation

    SciTech Connect (OSTI)

    Citir, Murat; Metz, Ricardo B.; Belau, Leonid; Ahmed, Musahid

    2008-07-21T23:59:59.000Z

    Photoionization efficiency curves were measured for gas-phase PtC, PtO, and PtO2 using tunable vacuum ultraviolet (VUV) radiation at the Advanced Light Source. The molecules were prepared by laser ablation of a platinum tube, followed by reaction with CH4 or N2O and supersonic expansion. These measurements providethe first directly measured ionization energy for PtC, IE(PtC) = 9.45 +- 0.05 eV. The direct measurement also gives greatly improved ionization energies for the platinum oxides, IE(PtO) = 10.0 +- 0.1 eV and IE(PtO2) = 11.35 +- 0.05 eV. The ionization energy connects the dissociation energies of the neutral and cation, leading to greatly improved 0 K bond dissociation energies for the neutrals: D0(Pt-C) = 5.95 +- 0.07 eV, D0(Pt-O)= 4.30 +- 0.12 eV, and D0(OPt-O) = 4.41 +- 0.13 eV, as well as enthalpies of formation for the gas-phase molecules Delta H0 f,0(PtC(g)) = 701 +- 7 kJ/mol, Delta H0f,0(PtO(g)) = 396 +- 12 kJ/mol, and Delta H0f,0(PtO2(g)) = 218 +- 11 kJ/mol. Much of the error in previous Knudsen cell measurements of platinum oxide bond dissociation energies is due to the use of thermodynamic second law extrapolations. Third law values calculated using statistical mechanical thermodynamic functions are in much better agreement with values obtained from ionization energies and ion energetics. These experiments demonstrate that laser ablation production with direct VUV ionization measurements is a versatile tool to measure ionization energies and bond dissociation energies for catalytically interesting species such as metal oxides and carbides.

  6. Fabrication of Pd/Pd-Alloy Films by Surfactant Induced Electroless Plating for Hydrogen Separation from Advanced Coal Gasification Processes

    SciTech Connect (OSTI)

    Ilias, Shamsuddin; Kumar, Dhananjay

    2012-07-31T23:59:59.000Z

    Dense Pd, Pd-Cu and Pd-Ag composite membranes on microporous stainless steel substrate (MPSS) were fabricated by a novel electroless plating (EP) process. In the conventional Pd-EP process, the oxidation-reduction reactions between Pd-complex and hydrazine result in an evolution of NH{sub 3} and N{sub 2} gas bubbles. When adhered to the substrate surface and in the pores, these gas bubbles hinder uniform Pd-film deposition which results in dendrite growth leading to poor film formation. This problem was addressed by introducing cationic surfactant in the electroless plating process known as surfactant induced electroless plating (SIEP). The unique features of this innovation provide control of Pd-deposition rate, and Pd-grain size distribution. The surfactant molecules play an important role in the EP process by tailoring grain size and the process of agglomeration by removing tiny gas bubbles through adsorption at the gas-liquid interface. As a result surfactant can tailor a nanocrystalline Pd, Cu and Ag deposition in the film resulting in reduced membrane film thickness. Also, it produces a uniform, agglomerated film structure. The Pd-Cu and Pd-Ag membranes on MPSS support were fabricated by sequential deposition using SIEP method. The pre- and post-annealing characterizations of these membranes (Pd, Pd-Cu and Pd-Ag on MPSS substrate) were carried out by SEM, EDX, XRD, and AFM studies. The SEM images show significant improvement of the membrane surface morphology, in terms of metal grain structures and grain agglomeration compared to the membranes fabricated by conventional EP process. The SEM images and helium gas-tightness studies indicate that dense and thinner films of Pd, Pd-Cu and Pd-Ag membranes can be produced with shorter deposition time using surfactant. H{sub 2} Flux through the membranes fabricated by SIEP shows large improvement compared to those by CEP with comparable permselectivity. Pd-MPSS composite membrane was subjected to test for long term performance and thermal cycling (573 - 723 - 573 K) at 15 psi pressure drop for 1200 hours. Pd membranes showed excellent hydrogen permeability and thermal stability during the operational period. Under thermal cycling (573 K - 873 K - 573 K), Pd-Cu-MPSS membrane was stable and retained hydrogen permeation characteristics for over three months of operation. From this limited study, we conclude that SIEP is viable method for fabrication of defect-free, robust Pd-alloy membranes for high-temperature H{sub 2}-separation applications.

  7. Kinetics of monolayer graphene growth by segregation on Pd(111)

    SciTech Connect (OSTI)

    Mok, H. S.; Murata, Y.; Kodambaka, S., E-mail: kodambaka@ucla.edu [Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, California 90095 (United States); Ebnonnasir, A.; Ciobanu, C. V. [Department of Mechanical Engineering and Materials Science Program, Colorado School of Mines, Golden, Colorado 80401 (United States); Nie, S.; McCarty, K. F. [Sandia National Laboratories, Livermore, California 94550 (United States)

    2014-03-10T23:59:59.000Z

    Using in situ low-energy electron microscopy and density functional theory calculations, we follow the growth of monolayer graphene on Pd(111) via surface segregation of bulk-dissolved carbon. Upon lowering the substrate temperature, nucleation of graphene begins on graphene-free Pd surface and continues to occur during graphene growth. Measurements of graphene growth rates and Pd surface work functions establish that this continued nucleation is due to increasing C adatom concentration on the Pd surface with time. We attribute this anomalous phenomenon to a large barrier for attachment of C adatoms to graphene coupled with a strong binding of the non-graphitic C to the Pd surface.

  8. Seed influence on the ferromagnetic resonance response of Co/Ni multilayers

    SciTech Connect (OSTI)

    Sabino, Maria Patricia Rouelli, E-mail: maria-sabino@dsi.a-star.edu.sg; Tran, Michael; Hin Sim, Cheow; Ji Feng, Ying; Eason, Kwaku [Data Storage Institute, Agency for Science, Technology and Research, 5 Engineering Drive 1, Singapore 117608 (Singapore)

    2014-05-07T23:59:59.000Z

    The effect of Pd and Ru seed layers on the magnetic properties of [Co/Ni]{sub N} multilayers with varying number of bilayer repeats N is investigated using vector network analyzer ferromagnetic resonance. The effective anisotropy field H{sub Keff} is found to increase with N for Ru seed, but decreases for Pd until N?=?15. As N is increased beyond 15, H{sub Keff} decreases for both seeds. In contrast, the damping parameter ? decreases with N regardless of the seed, showing a 1/N dependence. Taking spin pumping into account, the intrinsic damping ?{sub 0} for both Pd and Ru seeds reduce to ?{sub 0} ? 0.01. These results demonstrate that there can be a strong influence of the seed/Co interface on anisotropy, especially for sufficiently low N, but not necessarily on ?{sub 0}.

  9. Synthesis and Characterization of Pt(IV) Fluorescein Conjugates to Investigate Pt(IV) Intracellular Transformations

    E-Print Network [OSTI]

    Song, Ying

    Pt(IV) anticancer compounds typically operate as prodrugs that are reduced in the hypoxic environment of cancer cells, losing two axial ligands in the process to generate active Pt(II) species. Here we report the synthesis ...

  10. Scattering in PT-symmetric quantum mechanics

    SciTech Connect (OSTI)

    Cannata, Francesco [Istituto Nazionale di Fisica Nucleare, Sezione di Bologna and Dipartimento di Fisica dell' Universita, Via Irnerio 46, I 40126 Bologna (Italy)]. E-mail: Francesco.Cannata@bo.infn.it; Dedonder, Jean-Pierre [GMPIB Universite Paris 7 - Denis-Diderot, 2 Place Jussieu, F-75251, Paris Cedex 05 (France)]. E-mail: dedonder@paris7.jussieu.fr; Ventura, Alberto [Ente Nuove Tecnologie, Energia e Ambiente, Bologna and Istituto Nazionale di Fisica Nucleare, Sezione di Bologna (Italy)]. E-mail: Alberto.Ventura@bologna.enea.it

    2007-02-15T23:59:59.000Z

    A general formalism is worked out for the description of one-dimensional scattering in non-hermitian quantum mechanics and constraints on transmission and reflection coefficients are derived in the cases of P, T or PT invariance of the Hamiltonian. Applications to some solvable PT-symmetric potentials are shown in detail. Our main original results concern the association of reflectionless potentials with asymptotic exact PT symmetry and the peculiarities of separable kernels of non-local potentials in connection with Hermiticity, T invariance and PT invariance.

  11. PT2_US.xls

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for RenewableSpeedingBiomassPPPO Website Directory PPPOLarson.Cheryl A - PS-6v56PT2.

  12. Ni Ni: University of California - Los Angeles

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy:Nanowire Solar541,9337,2April 2013 ESH&SNextNexus of EnergyNi

  13. Adsorption, Desorption, and Clustering H20 on Pt (111). | EMSL

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

    Desorption, and Clustering H20 on Pt (111). Adsorption, Desorption, and Clustering H20 on Pt (111). Abstract: The adsorption, desorption, and clustering behavior of H20 on Pt(111)...

  14. Adsorption and Desorption of HCI on Pt(111). | EMSL

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

    Desorption of HCI on Pt(111). Adsorption and Desorption of HCI on Pt(111). Abstract: The adsorption and desorption of HCl on Pt(111) is investigated by temperature programmed...

  15. Oxygen Coverage Dependence of NO Oxidation on Pt(111). | EMSL

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

    Oxygen Coverage Dependence of NO Oxidation on Pt(111). Oxygen Coverage Dependence of NO Oxidation on Pt(111). Abstract: The interaction of NO with adsorbed atomic oxygen on Pt(111)...

  16. Crystalline Ice Growth on Pt(111): Observation of a Hydrophobic...

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

    Crystalline Ice Growth on Pt(111): Observation of a Hydrophobic Water Monolayer. Crystalline Ice Growth on Pt(111): Observation of a Hydrophobic Water Monolayer. Abstract: The...

  17. Enhanced Activity and Stability of Pt catalysts on Functionalized...

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

    Enhanced Activity and Stability of Pt catalysts on Functionalized Graphene Sheets for Electrocatalytic Oxygen Reduction . Enhanced Activity and Stability of Pt catalysts on...

  18. Development of Novel Non Pt Group Metal Electrocatalysts for...

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

    Novel Non Pt Group Metal Electrocatalysts for Proton Exchange Membrane Fuel Cell Applications Development of Novel Non Pt Group Metal Electrocatalysts for Proton Exchange Membrane...

  19. Thermoelectric effect in very thin film Pt/Au thermocouples

    E-Print Network [OSTI]

    Salvadori, M.C.; Vaz, A.R.; Teixeira, F.S.; Cattani, M.; Brown, I.G.

    2006-01-01T23:59:59.000Z

    TABLE I. Measured thermoelectric power S for samples ofThermoelectric effect in very thin film Pt/Au thermocouplesthickness dependence of the thermoelectric power of Pt films

  20. Carbon nanotubes decorated with Pt nanoparticles via electrostatic...

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

    Pt nanoparticles via electrostatic self-assembly: a highly active oxygen reduction Carbon nanotubes decorated with Pt nanoparticles via electrostatic self-assembly: a highly...

  1. INTRODUCTION Parkinson's disease (PD) is characterized pathologically by the

    E-Print Network [OSTI]

    Diggle, Peter J.

    females, with an average age of 61.45 years (youngest 42, oldest 75). Gender (male/female) 23/9 Hoehn & Yahr 1.0 5 Hoehn & Yahr 1.5 3 Hoehn & Yahr 2.0 24 Median PD onset age (years (interquartile range)) 61. Gender; 4.Current drug treatment for PD; 5. Hoehn & Yahr score; 6. Family history of PD; 7. Familial

  2. Au-Pt heteroaggregate dendritic nanostructures and Au-Pt alloy nanoparticles and their use as catalysts

    DOE Patents [OSTI]

    Eichhorn, Bryan W. (University Park, MD); Zhou, Shenghu (Greenbelt, MD); Jackson, Gregory Scott (University Park, MD)

    2011-10-18T23:59:59.000Z

    Au--Pt heteroaggregate dendritic nanostructures and AuPt alloy nanoparticles, and their use as anodic catalysts in fuel cells.

  3. au ag pd: Topics by E-print Network

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

    and theoretical approaches agreed well, demonstrating the potential use Wang, Lihong 19 NANO EXPRESS Open Access AuPd core-shell nanoparticles with varied hollow Energy Storage,...

  4. ag pd stainless: Topics by E-print Network

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

    PerfusionVentilation 12;Herz-, Thorax-, Transplantations- und Manstein, Dietmar J. 310 NANO EXPRESS Open Access AuPd core-shell nanoparticles with varied hollow Energy Storage,...

  5. Scanning tuneeling microscopy studies of fivefold surfaces of icosahedral Al-Pd-Mn quasicrystals and of thin silver films on those surfaces

    SciTech Connect (OSTI)

    Unal, Baris

    2008-12-01T23:59:59.000Z

    The present work in this dissertation mainly focuses on the clean fivefold surfaces of i-Al-Pd-Mn quasicrystals as well as the nucleation and growth of Ag films on these surfaces. In addition, Ag film growth on NiAl(110) has been explored in the frame of this dissertation. First, we have investigated the equilibration of a fivefold surface of icosahedral Al-Pd-Mn quasicrystal at 900-915 K and 925-950 K, using Omicron variable temperature scanning tunneling microscope (STM). Annealing at low temperatures resulted in many voids on some terraces while the others were almost void-free. After annealing at 925-950K, void-rich terraces became much rarer. Our STM images suggest that through growth and coalescence of the voids, a different termination becomes exposed on host terraces. All of these observations in our study indicate that even after the quasicrystalline terrace-step structure appears, it evolves with time and temperature. More specifically, based on the STM observations, we conclude that during the annealing a wide range of energetically similar layers nucleate as surface terminations, however, with increasing temperature (and time) this distribution gets narrower via elimination of the metastable void-rich terraces. Next, we have examined the bulk structural models of icosahedral Al-Pd-Mn quasicrystal in terms of the densities, compositions and interplanar spacings for the fivefold planes that might represent physical surface terminations. In our analyses, we mainly have focused on four deterministic models which have no partial or mixed occupancy but we have made some comparisons with an undeterministic model. We have compared the models with each other and also with the available experimental data including STM, LEED-IV, XPD and LEIS. In all deterministic models, there are two different families of layers (a pair of planes), and the nondeterministic model contains similar group of planes. These two families differ in terms of the chemical decoration of their top planes. Hence, we name them as Pd+(with Pd) and Pd-(without Pd). Based on their planer structure and the step height, it can be said that these two families can be viable surface terminations. However, besides the Pd content, these two sets differ in terms of relative densities of their top planes as well as the gap separating the layer from the nearest atomic plane. The experimental data and other arguments lead to the conclusion that the Pd- family is favored over the Pd+. This has an important implication on the interpretation of local motifs seen in the high resolution STM images. In other words, the dark stars are not formed by cut-Bergmans rather they are formed by cut-Mackays.

  6. Bulk Migration of Ni/NiO in Ni-YSZ during Reducing Conditions

    SciTech Connect (OSTI)

    Saraf, Laxmikant V.; Baer, Donald R.; Lea, Alan S.; Zhu, Zihua; Strohm, James J.; Sitzman, S. D.; King, David L.

    2010-02-09T23:59:59.000Z

    Understanding the migration of Ni/NiO in Ni-YSZ can potentially help to design a better solid oxide fuel cell (SOFC) anode. We have observed that extensive hydrogen reduction and methane steam reforming of Ni-YSZ caused bulk migration of Ni/NiO to at least ~ 5 µm deeper from the Ni-YSZ surface. No significant bulk migration effects were detected after simple thermal treatments in non-reducing/non-reforming environment. Surface analysis of a single zirconia grain in the first 10-20 nm region from annealed, hydrogen reduced and methane steam reformed Ni-YSZ shows Ni-enriched surface supporting earlier claims of Ni exsolution. 3D-EBSD analysis of thermally treated sample before exposing it to reducing and reforming environment indicated mixed NiO/YSZ phase with some porosity and random grain orientation. The surface analysis and mapping were carried out using ToF-SIMS and AES whereas EDS maps on FIB sliced areas on Ni-YSZ were utilized for the bulk analysis. The results provide additional information related to complex reactions occurring in SOFC during internal reforming conditions.

  7. Journal of the Korean Physical Society, Vol. 50, No. 6, June 2007, pp. 18941898 Investigation of the p-GaN Ohmic Contact Property

    E-Print Network [OSTI]

    Boo, Jin-Hyo

    O2/N2 ratio might keep the hole carriers from transporting to the electrode. PACS numbers: 81, 82 property. Many studies have been reported the preparation of a low resistance electrode by combining various metals, such as Pt/Au, Ti/Pt/Au, Pt/Au, Ni/Cr/Au, Pd/Au, and Ni/Au [4­7]. Among them, the Ni

  8. Atomic force microscopy and x-ray photoelectron spectroscopy investigations of the morphology and chemistry of a PdCl{sub 2}/SnCl{sub 2} electroless plating catalysis system adsorbed onto shape memory alloy particles

    SciTech Connect (OSTI)

    Silvain, J.F.; Fouassier, O.; Lescaux, S. [Institut de Chimie de la Matiere Condensee de Bordeaux (ICMCB) - CNRS, Universite de Bordeaux 1, 87 Avenue du Dr A. Schweitzer, F-33608 PESSAC (France); Veeco, Z.I. de la Gaudree, 11 Rue Marie Poussepin, F-91412 Dourdain (France)

    2004-11-01T23:59:59.000Z

    A study of the different stages of the electroless deposition of copper on micronic NiTi shape memory alloy particles activated by one-step and two-step methods has been conducted from both a chemical and a morphological point of view. The combination of x-ray photoelectron spectroscopy (XPS) measurements and atomic force microscopy (AFM) imaging has allowed detection of the distribution of the formed compounds and depth quantification and estimation of the surface topographic parameters. For the two-step method, at the sensitization of the early stages, it is observed by AFM that Sn is absorbed in form of clusters that tend to completely cover the surface and form a continuous film. XPS analysis have shown that Sn and Pd are first absorbed in form of oxide (SnO{sub 2} and PdO) and hydroxide [Sn(OH){sub 4}]. After the entire sensitization step, the NiTi substrate is covered with Sn-based compounds. After the sensitization and the activation steps the powder roughness increases. Behavior of the Sn and Pd growth for the one-step method does not follow the behavior found for the two-step method. Indeed, XPS analysis shows a three-dimensional (3D) growth of Pd clusters on top of a mixture of metallic tin, oxide (SnO) and hydroxide [Sn(OH){sub 2}]. These Pd clusters are covered with a thin layer of Pd-oxide contamination induced by the electroless process. The mean roughness for the one-step and two-step processes are equivalent. After copper deposition, the decrease of mean roughness is attributed to a filling of surface valleys, observed after the Sn-Pd coating step.

  9. This journal is c the Owner Societies 2013 Phys. Chem. Chem. Phys. Cite this: DOI: 10.1039/c3cp50793a

    E-Print Network [OSTI]

    properties, leading to tailored selectivity and enhanced chemical reactivity. In particular, the catalysis reforming reactions, including Au/Ni8 and Pt/Ni9 for methane steam reforming, and Zn/Pd which of Pd(111) surfaces with low (o0.5 ML) coverages of Zn. Based on LEED, Jeroro et al. propose that a p(2

  10. Electrochemical hydrogenation of aromatic compounds chemisorbed at polycrystalline and single-crystal Pd surfaces

    E-Print Network [OSTI]

    Sanabria-Chinchilla, Jean

    2009-06-02T23:59:59.000Z

    The chemisorption and electrochemical hydrogenation of hydroquinone (H2Q) at polycrystalline (pc) Pd, well-ordered Pd(100), and Pd-modified Au(hkl) electrodes were studied using a combination of ultra-high vacuum (UHV) surface spectroscopy...

  11. Structural and magnetic properties of the ordered FePt{sub 3}, FePt and Fe{sub 3}Pt nanoparticles

    SciTech Connect (OSTI)

    Liu, Yang [Institute of Condensed State Physics, Jilin Normal University, Siping 136000 (China); Key Laboratory of Functional Materials Physics and Chemistry (Jilin Normal University), Ministry of Education, Siping 136000 (China); Institute of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Jiang, Yuhong; Zhang, Xiaolong; Wang, Yaxin; Zhang, Yongjun; Liu, Huilian; Zhai, Hongju; Liu, Yanqing [Institute of Condensed State Physics, Jilin Normal University, Siping 136000 (China); Key Laboratory of Functional Materials Physics and Chemistry (Jilin Normal University), Ministry of Education, Siping 136000 (China); Yang, Jinghai, E-mail: jhyang1@jlnu.edu.cn [Institute of Condensed State Physics, Jilin Normal University, Siping 136000 (China); Key Laboratory of Functional Materials Physics and Chemistry (Jilin Normal University), Ministry of Education, Siping 136000 (China); Yan, Yongsheng, E-mail: yanyongsheng215@126.com [Institute of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2014-01-15T23:59:59.000Z

    The Fe{sub x}Pt{sub 100?x} nanoparticles (NPs) with different nominal atomic rations (30?x?80) were synthesized at 700 °C by the sol–gel method. The structure, morphology and magnetic properties of the samples were investigated. When the Fe content in the Fe–Pt alloy NPs was 30 at%, FePt{sub 3} NPs were successfully synthesized. With the increase in Fe content up to 50 at%, it was found that the superlattice reflections (0 0 1) and (1 1 0) appeared, which indicated the formation of the L1{sub 0}-FePt phase. Meanwhile, the FePt{sub 3} fraction was reduced. When the Fe content increased to 60 at%, single-phase L1{sub 0}-FePt NPs were synthesized. The coercivity (Hc), saturation magnetization (Ms) and chemical order parameter S for Fe{sub 60}Pt{sub 40} NPs were as high as 10,200 Oe, 17.567 emu/g and 0.928, respectively. With the further increase of the Fe content to 80 at%, only Fe{sub 3}Pt phase existed and the Hc of the Fe{sub 3}Pt NPs decreased drastically to 360 Oe. - Graphical abstract: Fe{sub 3}Pt, FePt and FePt{sub 3} nanoparticles was obtained by sol–gel method. The effect of iron and platinum content on structural and magnetic properties of the FePt nanoparticles was investigated. Display Omitted - Highlights: • L1{sub 2}-FePt{sub 3}, L1{sub 0}-FePt and L1{sub 2}-Fe{sub 3}Pt NPs were synthesized by sol–gel method. • The chemical order parameter S affects the magnetic properties of the Fe–Pt alloy. • Structural and magnetic properties of the Fe–Pt alloy NPs were studied. • The synthetic route in this study will open up the possibilities of practical use.

  12. 44 (2007-5) FT-ICR Pt,Co

    E-Print Network [OSTI]

    Maruyama, Shigeo

    44 (2007-5) FT-ICR Pt,Co FT-ICR study of reaction of Pt, Co cluster ion with carbon containing ions (Pt, Co) with carbon hydride was investigated by using FT-ICR (Fourier Transform Ion Cyclotron-dependent characteristics of reaction of Pt and Co clusters with methanol and ethylene. This experiment also shows

  13. PD Dr. Martin Stetter, Siemens AG 1 Optimierungsverfahren

    E-Print Network [OSTI]

    Popeea, Corneliu - Chair for Foundations of Software Reliability and Theoretical Computer Science

    PD Dr. Martin Stetter, Siemens AG 1 Optimierungsverfahren · Optimierung konvexer Funktionen: Optimierungsverfahren #12;PD Dr. Martin Stetter, Siemens AG 2 Optimierung konvexer Funktionen · Häufiges Problem bei Stetter, Siemens AG 3 Funktionen einer Variable )(wF · 1D-Gradientenabstieg: Gehe ein kleines Stück

  14. Location of platinum clusters in PtCaY and PtNaY zeolites

    E-Print Network [OSTI]

    Treybig, Duane Steven

    1980-01-01T23:59:59.000Z

    ) 350'C . . . ~ . . . . . . . . . . . . . 32 Pt 4f spectra of PtCaY: (A) after heating in flowing oxygen at 100'C for 2 hr, (B) after reduction in flowing hydrogen in increments of 100'C/hr to 350'C, (C) after deammination and dehydration in flowing... oxygen in incre- ments of 100'C/hr to 350'C, evacuation at 25'C followed by reduction in flowing hydrogen in increments oi 100'C/hr to 400'C Pt 4d spectra of PtCaY: (A) after heating in flowing oxygen at 100'C for 2 hr, (B) after reduction...

  15. Location of platinum clusters in PtCaY and PtNaY zeolites 

    E-Print Network [OSTI]

    Treybig, Duane Steven

    1980-01-01T23:59:59.000Z

    ) 350'C . . . ~ . . . . . . . . . . . . . 32 Pt 4f spectra of PtCaY: (A) after heating in flowing oxygen at 100'C for 2 hr, (B) after reduction in flowing hydrogen in increments of 100'C/hr to 350'C, (C) after deammination and dehydration in flowing... oxygen in incre- ments of 100'C/hr to 350'C, evacuation at 25'C followed by reduction in flowing hydrogen in increments oi 100'C/hr to 400'C Pt 4d spectra of PtCaY: (A) after heating in flowing oxygen at 100'C for 2 hr, (B) after reduction...

  16. Approved Module Information for PD1803, 2014/5 Module Title/Name: Engineering Principles Module Code: PD1803

    E-Print Network [OSTI]

    Neirotti, Juan Pablo

    Code: PD1803 School: Engineering and Applied Science Module Type: Standard Module New Module? No Module.i.smith@aston.ac.uk Telephone Number 3610 Office MB156C Additional Module Tutor(s): Michael David Peters. David Barry. LevelApproved Module Information for PD1803, 2014/5 Module Title/Name: Engineering Principles Module

  17. Approved Module Information for PD2003, 2014/5 Module Title/Name: Engineering Principles 2 Module Code: PD2003

    E-Print Network [OSTI]

    Neirotti, Juan Pablo

    Approved Module Information for PD2003, 2014/5 Module Title/Name: Engineering Principles 2 Module Code: PD2003 School: Engineering and Applied Science Module Type: Standard Module New Module? No Module.i.smith@aston.ac.uk Telephone Number 3610 Office MB156C Additional Module Tutor(s): Michael David Peters. David Barry. Level

  18. Pd and Pd-Cu Alloy Deposited Nafion Membranes for Reduction of Methanol Crossover in Direct Methanol

    E-Print Network [OSTI]

    Zhao, Tianshou

    Pd and Pd-Cu Alloy Deposited Nafion Membranes for Reduction of Methanol Crossover in Direct Methanol Fuel Cells J. Prabhuram, T. S. Zhao,*,z Z. X. Liang, H. Yang, and C. W. Wong Department Kong, China To reduce methanol crossover in direct methanol fuel cells DMFCs , Nafion 115 membrane

  19. Investigation of Pt, Pt3Co, and Pt3CoMo Cathodes for the ORR in a Microfluidic H2O2 Fuel Cell

    E-Print Network [OSTI]

    Kenis, Paul J. A.

    Investigation of Pt, Pt3Co, and Pt3CoÕMo Cathodes for the ORR in a Microfluidic H2ÕO2 Fuel Cell on the performance and durability of four Pt-based cathode catalysts in a microfluidic H2/O2 fuel cell: commercial performed using an acidic microfluidic H2/O2 fuel cell with an analytical platform. The electrolyte flow

  20. Doped Graphene as a Material for Oxygen Reduction Reaction in Hydrogen Fuel Cells: A Computational Study

    E-Print Network [OSTI]

    Krasheninnikov, Arkady V.

    in graphene. Our results indicate that single Ni, Pd, Pt, Sn, and P atoms embedded into divacancies the reaction kinetics and give rise to heating. In the ideal cathode reaction (cathode is the electrode where

  1. Neutral bimetallic transition metal phenoxyiminato catalysts and related polymerization methods

    DOE Patents [OSTI]

    Marks, Tobin J. (Evanston, IL); Rodriguez, Brandon A. (Evanston, IL); Delferro, Massimiliano (Chicago, IL)

    2012-08-07T23:59:59.000Z

    A catalyst composition comprising a neutral bimetallic diphenoxydiiminate complex of group 10 metals or Ni, Pd or Pt is disclosed. The compositions can be used for the preparation of homo- and co-polymers of olefinic monomer compounds.

  2. May 22, 2003 DOE Hydrogen and Fuel Cells 2003 Annual Merit Review

    E-Print Network [OSTI]

    (Ceria) electrolytes · Use various (Pt, Pd, Au, Ni) metal electrode combinations H2 + OO H2O + VO .. + 2e- CO + OO CO Nafion® as the proton conducting membrane · Use Pt or Ru electrode as working electrode · Electrode is sensitive to CO poisoning · Use Pt-Ru electrode as a counter electrode · Electrode is tolerant

  3. A comparative first-principles study of martensitic phase transformations in TiPd2 and TiPd

    SciTech Connect (OSTI)

    Krcmar, Maja [Grand Valley State University (GVSU), Michigan] [Grand Valley State University (GVSU), Michigan; Morris, James R [ORNL] [ORNL

    2014-01-01T23:59:59.000Z

    Martensitic phase transformations in TiPd2 and TiPd alloys are studied employing density-functional, first-principles calculations. We examine the transformation of tetragonal C11b TiPd2 to the low-temperature orthorhombic phase (C11b oI6), and the transformation of cubic B2 TiPd under orthorhombic (B2 B19) and subsequent monoclinic transformations (B19 B19 ) as the system is cooled. To evaluate the transition temperature for TiPd2 we employ a theoretical approach based on a phenomenological Landau theory of the structural phase transition and a mean-field approximation for the free energy, utilizing first-principles calculations to obtain the deformation energy as a function of strains and to deduce parameters for constructing the free energy. The predicted transition temperature for the TiPd2 C11b oI6 transition temperature is in good agreement with reported experimental results. To investigate the TiPd B2 B19 transformation, we employ both the Cauchy-Born rule and a soft-mode- based approach, and elucidate on the importance of coupling of lattice distortion and atomic displacements (i.e., shuffling) in the formation of the final structure. The estimated B2 B19 transition temperature for TiPd system agrees well with the experimental results. We also find that there exists a very small but finite (0.0005 eV/atom) energy barrier of B19 TiPd under monoclinic deformation for B19 B19 structural phase transformation.

  4. ENHANCEMENT OF SUPERCONDUCTING Tc IN Pd-H LIKE COMPOUNDS BY OPTICAL PHONONS

    E-Print Network [OSTI]

    Boyer, Edmond

    1227 ENHANCEMENT OF SUPERCONDUCTING Tc IN Pd-H LIKE COMPOUNDS BY OPTICAL PHONONS J. P. BURGER and D.450 1. Introduction. - The high superconducting tran- sition temperatures recently observed in Pd [1 interaction inhibiting superconductivity in pure Pd. As the density of states in Pd-H is rather similar [5

  5. Jet energy scale setting with "photon+Jet" events at LHC energies. Selection of events with a clean "photon+Jet" topology and photon Pt - jet Pt disbalance

    E-Print Network [OSTI]

    D. V. Bandourin; V. F. Konoplyanikov; N. B. Skachkov

    2001-04-27T23:59:59.000Z

    It is shown in the paper that Pt activity limitation (modulus of the vector sum) of all particle beyond "photon+Jet" system Pt^out leads to the noticeable photon Pt - jet Pt disbalance decreasing. On a simultaneous restriction of the cluster Pt and Pt^out from above it is possible to reach an acceptable balance between photon Pt - jet Pt with a sufficient number of the photon Pt - jet Pt events for the jet energy scale setting and hadron calorimeter calibratiom of the CMS detector at LHC.

  6. Enhanced collectivity in 74Ni

    E-Print Network [OSTI]

    N. Aoi; S. Kanno; S. Takeuchi; H. Suzuki; D. Bazin; M. D. Bowen; C. M. Campbell; J. M. Cook; D. -C. Dinca; A. Gade; T. Glasmacher; H. Iwasaki; T. Kubo; K. Kurita; T. Motobayashi; W. F. Mueller; T. Nakamura; H. Sakurai; M. Takashina; J. R. Terry; K. Yoneda; H. Zwahlen

    2010-08-03T23:59:59.000Z

    The neutron-rich nucleus 74Ni was studied with inverse-kinematics inelastic proton scattering using a 74Ni radioactive beam incident on a liquid hydrogen targetat a center-of-mass energy of 80 MeV. From the measured de-excitation gamma-rays, the population of the first 2+ state was quantified. The angle-integrated excitation cross section was determined to be 14(4) mb. A deformation length of delta = 1.04(16) fm was extracted in comparison with distorted wave theory, which suggests that the enhancement of collectivity established for 70Ni continues up to 74Ni. A comparison with results of shell model and quasi-particle random phase approximation calculations indicates that the magic character of Z = 28 or N = 50 is weakened in 74Ni.

  7. Catalytic studies of supported Pd-Au catalysts 

    E-Print Network [OSTI]

    Boopalachandran, Praveenkumar

    2006-08-16T23:59:59.000Z

    Although Pd-Au high-surface area catalysts are used in industry to improve activity and selectivity, a thorough understanding of the nature of these enhancements is lacking. A molecular-level understanding of catalytic ...

  8. The Role of the PD-1 Immunoreceptor in Pregnancy

    E-Print Network [OSTI]

    Taglauer, Elizabeth Susan

    2008-08-08T23:59:59.000Z

    During pregnancy, the maternal immune system must be carefully modulated as the fetus is immunologically foreign to her leukocytes. We propose that the CD28 family immune receptor, PD-1, functions during pregnancy to control maternal immune...

  9. The PD-1/PD-L1 complex resembles the antigen-binding Fv domains of antibodies and T cell receptors

    SciTech Connect (OSTI)

    Lin, David Yin-wei; Tanaka, Yoshimasa; Iwasaki, Masashi; Gittis, Apostolos G.; Su, Hua-Poo; Mikami, Bunzo; Okazaki, Taku; Honjo, Tasuku; Minato, Nagahiro; Garboczi, David N. (NIH); (Kyoto)

    2008-07-29T23:59:59.000Z

    Signaling through the programmed death 1 (PD-1) inhibitory receptor upon binding its ligand, PD-L1, suppresses immune responses against autoantigens and tumors and plays an important role in the maintenance of peripheral immune tolerance. Release from PD-1 inhibitory signaling revives 'exhausted' virus-specific T cells in chronic viral infections. Here we present the crystal structure of murine PD-1 in complex with human PD-L1. PD-1 and PD-L1 interact through the conserved front and side of their Ig variable (IgV) domains, as do the IgV domains of antibodies and T cell receptors. This places the loops at the ends of the IgV domains on the same side of the PD-1/PD-L1 complex, forming a surface that is similar to the antigen-binding surface of antibodies and T cell receptors. Mapping conserved residues allowed the identification of residues that are important in forming the PD-1/PD-L1 interface. Based on the structure, we show that some reported loss-of-binding mutations involve the PD-1/PD-L1 interaction but that others compromise protein folding. The PD-1/PD-L1 interaction described here may be blocked by antibodies or by designed small-molecule drugs to lower inhibitory signaling that results in a stronger immune response. The immune receptor-like loops offer a new surface for further study and potentially the design of molecules that would affect PD-1/PD-L1 complex formation and thereby modulate the immune response.

  10. Composite Pd and Pd Alloy Porous Stainless Steel Membranes for Hydrogen Production and Process Intensification

    SciTech Connect (OSTI)

    Yi Hua Ma; Nikolaos Kazantzis; Ivan Mardilovich; Federico Guazzone; Alexander Augustine; Reyyan Koc

    2011-11-06T23:59:59.000Z

    The synthesis of composite Pd membranes has been modified by the addition of a Al(OH){sub 3} graded layer and sequential annealing at high temperatures to obtain membranes with high permeance and outstanding selectivity stability for over 4000 hours at 450°C. Most of the membranes achieved in this work showed H{sub 2} flux well above 2010 DOE targets and in some case, also above 2015 DOE targets. Similar composite membranes were tested in water gas shift reaction atmospheres and showed to be stable with high CO conversion and high hydrogen recovery for over 1000 hours. The H{sub 2} permeance of composite Pd-Au membranes was studied as well as its resistance in H{sub 2}S containing atmospheres. H{sub 2}S poisoning of Pd-based membranes was reduced by the addition of Au and the loss undergone by membranes was found to be almost totally recoverable with 10-30 wt%Au. PSA technique was studied to test the possibility of H{sub 2}S and COS removal from feed stream with limited success since the removal of H{sub 2}S also led to the removal of a large fraction of the CO{sub 2}. The economics of a WGS bundle reactor, using the information of the membranes fabricated under this project and integrated into an IGCC plant were studied based on a 2D reactor modeling. The calculations showed that without a government incentive to impose a CO{sub 2} tax, application of WGS membrane reactors in IGCC would be not as economically attractive as regular pulverized coal plants.

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

    DOE Patents [OSTI]

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

    2013-12-17T23:59:59.000Z

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

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

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

    Yue, G. Q.; Zhang, Y.; Sun, Y.; Shen, B.; Dong, F.; Wang, Z. Y.; Zhang, R. J.; Zheng, Y. X.; Kramer, M. J.; Wang, S. Y.; et al

    2015-02-05T23:59:59.000Z

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

  13. Growth of Ordered Ultrathin Tungsten Oxide Films on Pt(111)....

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

    Growth of Ordered Ultrathin Tungsten Oxide Films on Pt(111). Growth of Ordered Ultrathin Tungsten Oxide Films on Pt(111). Abstract: Ordered tungsten oxide ultra-thin films were...

  14. Thermal Treatment of PtNiCo Electrocatalysts: Effects of Nanoscale...

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

    of an investigation of the thermal treatment temperature on nanoengineered platinum-nickel-cobalt catalysts for oxygen reduction reaction, focusing on understanding the effects...

  15. Granular nanostructures and magnetic characteristics of FePt-TiO{sub 2}/FePt-C stacked granular films

    SciTech Connect (OSTI)

    Ono, Takuya, E-mail: ono-takuya@fujielectric.co.jp; Moriya, Tomohiro [Fuji Electric Co. Ltd., Tokyo 191-8502 (Japan); Frontier Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University, Miyagi 980-8578 (Japan); Hatayama, Masatoshi [Frontier Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University, Miyagi 980-8578 (Japan); Kikuchi, Nobuaki; Okamoto, Satoshi; Kitakami, Osamu [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Miyagi 980-8577 (Japan); Shimatsu, Takehito [Frontier Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University, Miyagi 980-8578 (Japan); Research institutes of Electrical Communication (RIEC), Tohoku University, Miyagi 980-8577 (Japan)

    2014-05-07T23:59:59.000Z

    To realize a granular film composed of L1{sub 0}-FePt grains with high uniaxial magnetic anisotropy energy, K{sub u}, and segregants for heat-assisted magnetic recording, the FePt-TiO{sub 2}/FePt-C stacked film was investigated. The FePt-TiO{sub 2}/FePt-C stacked film has well-isolated granular structure with average grain size of 6.7?nm because the FePt-TiO{sub 2} film follows the FePt-C template film in microstructural growth. However, the K{sub u} value is quite low for total thickness of 9?nm: 5?×?10{sup 6} erg/cm{sup 3}. Exploration of the thickness dependence of L1{sub 0}-FePt(001) peaks in XRD spectra and cross-sectional TEM images suggest that degradation of the L1{sub 0} ordering appears near the middle of the FePt-TiO{sub 2} layer. The EDX-STEM mapping reveals that Ti atoms exist within the FePt grains in addition to the grain boundary. This indicates the possibility that TiO{sub 2} tends to be incorporated into the FePt grains and that it prevents L1{sub 0}-ordering of the FePt grains along the normal-to-plane direction.

  16. Effect of nitrogen upon structural and magnetic properties of FePt in FePt/AlN multilayer structures

    SciTech Connect (OSTI)

    Gao, Tenghua, E-mail: gao.t.ab@m.titech.ac.jp; Zhang, Cong; Sannomiya, Takumi; Muraishi, Shinji; Nakamura, Yoshio; Shi, Ji [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1 Oh-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2014-09-01T23:59:59.000Z

    This paper investigates the effect of the addition of nitrogen in FePt layers for ultrathin FePt/AlN multilayer structures. X-ray diffraction results reveal that a compressive stress relaxation occurs after annealing owing to the release of interstitial nitrogen atoms in the FePt layers. The introduction of nitrogen also induces a large in-plane compressive strain during grain growth not seen in FePt deposited without nitrogen. This strain is considered to decrease the driving force for (111) grain growth and FePt ordering.

  17. Method for making MgO buffer layers on rolled nickel or copper as superconductor substrates

    DOE Patents [OSTI]

    Paranthaman, Mariappan (Knoxville, TN); Goyal, Amit (Knoxville, TN); Kroeger, Donald M. (Knoxville, TN); List, III, Frederic A. (Andersonville, TN)

    2002-01-01T23:59:59.000Z

    Buffer layer architectures are epitaxially deposited on biaxially-textured rolled-Ni and/or Cu substrates for high current conductors, and more particularly buffer layer architectures such as MgO/Ag/Pt/Ni, MgO/Ag/Pd/Ni, MgO/Ag/Ni, MgO/Ag/Pd/Cu, MgO/Ag/Pt/Cu, and MgO/Ag/Cu. Techniques used to deposit these buffer layers include electron beam evaporation, thermal evaporation, rf magnetron sputtering, pulsed laser deposition, metal-organic chemical vapor deposition (MOCVD), combustion CVD, and spray pyrolysis.

  18. MgO buffer layers on rolled nickel or copper as superconductor substrates

    DOE Patents [OSTI]

    Paranthaman, Mariappan (Knoxville, TN); Goyal, Amit (Knoxville, TN); Kroeger, Donald M. (Knoxville, TN); List, III, Frederic A. (Andersonville, TN)

    2001-01-01T23:59:59.000Z

    Buffer layer architectures are epitaxially deposited on biaxially-textured rolled-Ni and/or Cu substrates for high current conductors, and more particularly buffer layer architectures such as MgO/Ag/Pt/Ni, MgO/Ag/Pd/Ni, MgO/Ag/Ni, MgO/Ag/Pd/Cu, MgO/Ag/Pt/Cu, and MgO/Ag/Cu. Techniques used to deposit these buffer layers include electron beam evaporation, thermal evaporation, rf magnetron sputtering, pulsed laser deposition, metal-organic chemical vapor deposition (MOCVD), combustion CVD, and spray pyrolysis.

  19. Overview of TRAC-PD2 assessment calculations

    SciTech Connect (OSTI)

    Waterman, M E

    1985-11-01T23:59:59.000Z

    A summary of Transient Reactor Analysis Code Version PD2 (TRAC-PD2) calculations performed at the Idaho National Engineering Laboratory (INEL) is presented in this report as part of the US Nuclear Regulatory Commission's (NRCs) overall assessment program of TRAC-PD2. The calculated and measured parameters summarized in this report are break mass flow rate, primary coolant system pressure, reactor core flow rates, and fuel rod cladding temperatures. The data were obtained from seven tests that were performed at two test facilities. The tests were conducted to study the various aspects of cold leg break transients, including the effects of large and small beaks, and core reflood phenomena. User experience gained from the various calculations is also summarized. 42 figs., 10 tabs.

  20. Influence of nuclear structure on sub-barrier hindrance in Ni+Ni fusion

    E-Print Network [OSTI]

    C. L. Jiang; K. E. Rehm; R. V. F. Janssens; H. Esbensen; I. Ahmad; B. B. Back; P. Collon; C. N. Davids; J. P. Greene; D. J. Henderson; G. Mukherjee; R. C. Pardo; M. Paul; T. O. Pennington; D. Seweryniak; S. Sinha; Z. Zhou

    2004-02-25T23:59:59.000Z

    Fusion-evaporation cross sections for $^{64}$Ni+$^{64}$Ni have been measured down to the 10 nb level. For fusion between two open-shell nuclei, this is the first observation of a maximum in the $S$-factor, which signals a strong sub-barrier hindrance. A comparison with the $^{58}$Ni+$^{58}$Ni, $^{58}$Ni+$^{60}$Ni, and $^{58}$Ni+$^{64}$Ni systems indicates a strong dependence of the energy where the hindrance occurs on the stiffness of the interacting nuclei.

  1. Antiproton Production in p+d Reaction at Subthreshold Energies

    E-Print Network [OSTI]

    A. Hasegawa; Y. Iwasaki; K. Sakamoto; N. Noda; H. Kouno; M. Nakano

    1998-03-25T23:59:59.000Z

    An enhancement of antiprotons produced in p+d reaction in comparison with ones in p+p elementary reaction is investigated. In the neighborhood of subthreshold energy the enhancement is caused by the difference of available energies for antiproton production. The cross section in p+d reaction, on the other hand, becomes just twice of the one in elementary p+p reaction at the incident energy far from the threshold energy when non-nucleonic components in deuteron target are not considered.

  2. PD Dr. Martin Stetter, Siemens AG 1 Neuronale Verfahren zur Regression

    E-Print Network [OSTI]

    Popeea, Corneliu - Chair for Foundations of Software Reliability and Theoretical Computer Science

    PD Dr. Martin Stetter, Siemens AG 1 Neuronale Verfahren zur Regression · Lineares Modell · Vom: Optimierungsverfahren #12;PD Dr. Martin Stetter, Siemens AG 2 Optimierung konvexer Funktionen · Häufiges Problem bei

  3. Methanol Synthesis from CO2 Hydrogenation over a Pd4/In2O3 Model...

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

    Synthesis from CO2 Hydrogenation over a Pd4In2O3 Model Catalyst: A Combined DFT and Kinetic Study. Methanol Synthesis from CO2 Hydrogenation over a Pd4In2O3 Model Catalyst: A...

  4. Development and Applications of Pd Catalysts for C-N Cross-Coupling Reactions

    E-Print Network [OSTI]

    Fors, Brett P

    2011-01-01T23:59:59.000Z

    Chapter 1 A procedure for forming a highly active Pd(0) catalyst from Pd(OAc) 2, water, and biarylphosphine ligands has been developed. This protocol generates a catalyst system, which exhibits excellent reactivity and ...

  5. Comparative and Functional Genomics of Rhodococcus opacus PD630 for Biofuels Development

    E-Print Network [OSTI]

    Sinskey, Anthony J.

    Comparative and Functional Genomics of Rhodococcus opacus PD630 for Biofuels Development Jason W and Functional Genomics of Rhodococcus opacus PD630 for Biofuels Development. PLoS Genet 7(9): e1002219. doi:10

  6. Carbon-Supported bimetallic Pd-Fe catalysts for vapor-phasehydrodeoxy...

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

    Carbon-Supported bimetallic Pd-Fe catalysts for vapor-phase hydrodeoxygenation of guaiacol. Carbon-Supported bimetallic Pd-Fe catalysts for vapor-phase hydrodeoxygenation of...

  7. Syngas Conversion to Gasoline-Range Hydrocarbons over Pd/ZnO...

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

    Syngas Conversion to Gasoline-Range Hydrocarbons over PdZnOAl2O3 and ZSM-5 Composite Catalyst System. Syngas Conversion to Gasoline-Range Hydrocarbons over PdZnOAl2O3 and ZSM-5...

  8. PdZnAl Catalysts for the Reactions of Water-Gas-Shift, Methanol...

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

    PdZnAl Catalysts for the Reactions of Water-Gas-Shift, Methanol Steam Reforming, and Reverse-Water-Gas-Shift. PdZnAl Catalysts for the Reactions of Water-Gas-Shift, Methanol Steam...

  9. CO/FTIR Spectroscopic Characterization of Pd/ZnO/Al2O3 Catalysts...

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

    COFTIR Spectroscopic Characterization of PdZnOAl2O3 Catalysts for Methanol Steam Reforming. COFTIR Spectroscopic Characterization of PdZnOAl2O3 Catalysts for Methanol Steam...

  10. An exactly solvable PT symmetric potential from the Natanzon class

    E-Print Network [OSTI]

    G. Levai; A. Sinha; P. Roy

    2003-06-04T23:59:59.000Z

    The ${\\cal PT}$ symmetric version of the generalised Ginocchio potential, a member of the general exactly solvable Natanzon potential class is analysed and its properties are compared with those of ${\\cal PT}$ symmetric potentials from the more restricted shape-invariant class. It is found that the ${\\cal PT}$ symmetric generalised Ginocchio potential has a number of properties in common with the latter potentials: it can be generated by an imaginary coordinate shift $x\\to x+{\\rm i}\\epsilon$; its states are characterised by the quasi-parity quantum number; the spontaneous breakdown of ${\\cal PT}$ symmetry occurs at the same time for all the energy levels; and it has two supersymmetric partners which cease to be ${\\cal PT}$ symmetric when the ${\\cal PT}$ symmetry of the original potential is spontaneously broken.

  11. Hydrogen Absorption in Pd-based Nanostructures - Final Report

    SciTech Connect (OSTI)

    David Lederman

    2012-10-22T23:59:59.000Z

    Pd is known to absorb hydrogen. Molecules are normally chemisorbed at the surface in a process where the molecule breaks into two hydrogen atoms, and the protons are then absorbed into the bulk. This process consists of electron filling holes in the Pd 4d band near the Fermi energy, which due to the high density of states at the Fermi energy, is an energetically favorable process. Our aim with this project was to determine possible changes in magnetic properties with Pd nm-length-scale thick layers intercalated by magnetic materials. Before the start of this work, the literature indicated that there were several possible scenarios by which this could happen: i) the Pd will be magnetized due to a proximity effect with nearby magnetic layers, resulting in changes in the magnetization due to H2 absorption; ii) some H will be absorbed into the magnetic layers, causing a change in the magnetic exchange interactions; or iii) absorption of H2 will cause an expansion of the lattice, resulting in a magnetoelastic effect which changes the magnetic properties.

  12. Catalytic studies of supported Pd-Au catalysts

    E-Print Network [OSTI]

    Boopalachandran, Praveenkumar

    2006-08-16T23:59:59.000Z

    . This surface modification is an important factor in the altered reaction kinetics for vinyl acetate (VA) synthesis and CO oxidation reactions. Promoted and unpromoted Pd-Au/SiO2/K+ catalyst were used for VA synthesis and the effect of pre-adsorbed O2, acetic...

  13. NANO EXPRESS Open Access Au/Pd core-shell nanoparticles with varied hollow

    E-Print Network [OSTI]

    Liu, Fuqiang

    NANO EXPRESS Open Access Au/Pd core-shell nanoparticles with varied hollow Au cores for enhanced has been developed to synthesize Au/Pd core-shell nanoparticles via galvanic replacement of Cu by Pd on hollow Au nanospheres. The unique nanoparticles were characterized by X-ray diffraction, X

  14. Ethylene combustion on unsupported and supported Pd: a comparative , Y.-F. Hana,b

    E-Print Network [OSTI]

    Goodman, Wayne

    Ethylene combustion on unsupported and supported Pd: a comparative study D. Kumara , Y.-F. Hana Ethylene combustion is studied at elevated pressures on Pd(100) and compared with supported Pd catalysts with increasing O2 pressure. The combustion kinetics is related to the corresponding surface carbon coverage

  15. subm. to PCCP Geometric and electronic structure of Pd/4-aminothiophenol/Au(111)

    E-Print Network [OSTI]

    Pfeifer, Holger

    in order to prevent the formation of the adsorption of Pd on the Au electrode [2, 3, 7­9]. The fact that the Pd layer is indeed deposited on top of the SAM and does not bind directly to the metal electrodesubm. to PCCP Geometric and electronic structure of Pd/4-aminothiophenol/Au(111) metal

  16. Elevated expression of ERK 2 in human tumor cells chronically treated with PD98059

    SciTech Connect (OSTI)

    Kanda, Shigeru [Department of Molecular Microbiology and Immunology, Division of Endothelial Cell Biology, Nagasaki University Graduate School of Biomedical Science, Nagasaki (Japan)]. E-mail: skanda-jua@umin.net; Kanetake, Hiroshi [Department of Urology, Nagasaki University Graduate School of Biomedical Science, Nagasaki (Japan); Miyata, Yasuyoshi [Department of Urology, Nagasaki University Graduate School of Biomedical Science, Nagasaki (Japan)

    2006-07-14T23:59:59.000Z

    We examined the effect of chronic exposure of tumor cells to a mitogen-activated protein kinase/extracellular signal-regulated kinases (ERK) kinase inhibitor, PD98059, on cell proliferation was investigated. Human renal carcinoma cells (ACHN) and prostatic carcinoma cells (DU145) were cultured in the presence of PD98059 for more than 4 weeks (denoted ACHN (PD) cells and DU145 (PD) cells, respectively) and proliferation and signal transduction pathways were examined. PD98059 significantly inhibited the proliferation of parental cells. However, PD98059 failed to inhibit proliferation of ACHN (PD) and DU145 (PD) cells significantly. Expression of ERK 1 and 2 was elevated in these cells. These phenotypes were reversible. Downregulation of ERK 2, but not ERK 1, by small interfering RNA significantly inhibited the proliferation of ACHN (PD) and DU145 (PD) cells. Taken together, chronic exposure of tumor cells to PD98059 induced elevated expression of ERK 2, which was associated with decreased sensitivity of cellular proliferation to PD98059.

  17. PD Dr. Martin Stetter, Siemens AG 1 Neuronale Lernverfahren fr Klassifikation

    E-Print Network [OSTI]

    Popeea, Corneliu - Chair for Foundations of Software Reliability and Theoretical Computer Science

    PD Dr. Martin Stetter, Siemens AG 1 Neuronale Lernverfahren für Klassifikation · Das Perceptron #12;PD Dr. Martin Stetter, Siemens AG 2 Das Perceptron Klassifikation: Perceptron · Neuronale Struktur- Klassifikationsfehler 1x w )(m x 1)( =m y 0^ =y 1^ +=y 2x #12;PD Dr. Martin Stetter, Siemens AG 3Klassifikation

  18. PD Dr. Martin Stetter, Siemens AG 1 Lernen von Datenmodellen: Fehlerminimierung und Regularisierung

    E-Print Network [OSTI]

    Popeea, Corneliu - Chair for Foundations of Software Reliability and Theoretical Computer Science

    PD Dr. Martin Stetter, Siemens AG 1 Lernen von Datenmodellen: Fehlerminimierung und Regularisierung: Fehlerminimierung #12;PD Dr. Martin Stetter, Siemens AG 2 Maximum-Likelihood und Fehlerminimierung · Likelihood: Fehlerfunktionen #12;PD Dr. Martin Stetter, Siemens AG 3 · Def. Fehlerfunktion: 0))|(,,( wxfyxl yxyyx ,0),,( =lmit

  19. PD Dr. Martin Stetter, Siemens AG 1 Lernen von Datenmodellen: Approximation

    E-Print Network [OSTI]

    Popeea, Corneliu - Chair for Foundations of Software Reliability and Theoretical Computer Science

    PD Dr. Martin Stetter, Siemens AG 1 Lernen von Datenmodellen: Approximation · Bayes`sches Schließen: Approximation #12;PD Dr. Martin Stetter, Siemens AG 2 Ziel maschinellen Lernens (=statistische Inferenz) · Man Datenmodellen: Approximation #12;PD Dr. Martin Stetter, Siemens AG 3 Bayes`sches Schließen · Es gilt, die Daten

  20. PD Dr. Martin Stetter, Siemens AG 1 Neuronale Verfahren zur Regression

    E-Print Network [OSTI]

    Popeea, Corneliu - Chair for Foundations of Software Reliability and Theoretical Computer Science

    PD Dr. Martin Stetter, Siemens AG 1 Neuronale Verfahren zur Regression · Lineares Modell · Vom-Netze Regression #12;PD Dr. Martin Stetter, Siemens AG 2 Das lineare Modell · Ausgangspunkt: Lineares Perceptron vorgegeben, werden nicht gelernt #12;PD Dr. Martin Stetter, Siemens AG 3 · Geschrieben als Regressionsmodell

  1. Physical mechanism of reectance inversion in hydrogen gas sensor with Pd/PVDF structures

    E-Print Network [OSTI]

    Mandelis, Andreas

    , and industrial sectors. As part of the infrastructure of hydrogen-based technologies, the development of reliablePhysical mechanism of re¯ectance inversion in hydrogen gas sensor with Pd/PVDF structures Chinhua in thin-®lm Pd on polyvinylidene ¯uoride (PVDF) optical hydrogen sensor structures (Pd/PVDF) upon exposure

  2. New Exactly Solvable Isospectral Partners for PT Symmetric Potentials

    E-Print Network [OSTI]

    Anjana Sinha; Pinaki Roy

    2003-12-18T23:59:59.000Z

    We examine in detail the possibilty of applying Darboux transformation to non Hermitian hamiltonians. In particular we propose a simple method of constructing exactly solvable PT symmetric potentials by applying Darboux transformation to higher states of an exactly solvable PT symmetric potential. It is shown that the resulting hamiltonian and the original one are pseudo supersymmetric partners. We also discuss application of Darboux transformation to hamiltonians with spontaneously broken PT symmetry.

  3. PtRu/Carbon Nanotube Nanocomposite Synthesized in Supercritical...

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

    Synthesized in Supercritical Fluid: A Novel Electrocatalyst for Direct Methanol Fuel Cell. PtRuCarbon Nanotube Nanocomposite Synthesized in Supercritical Fluid: A Novel...

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

    E-Print Network [OSTI]

    Ross, Jr., Philip N.

    2012-01-01T23:59:59.000Z

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

  5. Graphene decorated with PtAu alloy nanoparticles: facile synthesis...

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

    nanoparticles: facile synthesis and promising application for formic acid oxidation. Graphene decorated with PtAu alloy nanoparticles: facile synthesis and promising application...

  6. Effect of reductive treatments on Pt behavior and NOx storage...

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

    represent a promising approach to meet increasingly stringent NOx emission regulations on diesel and other lean-burn engines. Pt material properties, including dispersion and...

  7. Infrared diode laser spectroscopy of jet-cooled NiCO, Ni,,CO...3,,13 and Ni,,CO...3,,C18

    E-Print Network [OSTI]

    Morse, Michael D.

    Infrared diode laser spectroscopy of jet-cooled NiCO, Ni,,CO...3,,13 CO..., and Ni,,CO...3,,C18 O infrared spectroscopic investigations of the CO vibration of jet-cooled NiCO, Ni CO 3 13 CO , and Ni CO 3 C diode laser spectrometer. The rotationally resolved spectrum of NiCO was collected as it was formed

  8. Strengthened PT-symmetry with P $\

    E-Print Network [OSTI]

    Miloslav Znojil

    2006-01-09T23:59:59.000Z

    Two alternative scenarios are shown possible in Quantum Mechanics working with non-Hermitian $PT-$symmetric form of observables. While, usually, people assume that $P$ is a self-adjoint indefinite metric in Hilbert space (and that their $P-$pseudo-Hermitian Hamiltonians $H$ possess the real spectra etc), we propose to relax the constraint $P=P^\\dagger$ as redundant. Non-Hermitian triplet of coupled square wells is chosen for illustration purposes. Its solutions are constructed and the observed degeneracy of their spectrum is attributed to the characteristic nontrivial symmetry $S={P}^{-1} {P}^\\dagger \

  9. In Situ Generation of Pd/PdO Nanoparticle Methane Combustion Catalyst: Correlation of Particle Surface Chemistry with Ignition

    E-Print Network [OSTI]

    Anderson, Scott L.

    supported in fixed-bed reactors. The extensive work on the kinetics of Pd oxidation and its relation applications, the typical fixed-bed catalytic reactor approach is not possible because of the high flow performance of propulsion platforms. Catalysts are needed both to enhance and control endothermic reactions

  10. Sulfur Tolerant Pd/Cu and Pd/Au Alloy Membranes for H2 Separation with High Pressure CO2 for Sequestration

    SciTech Connect (OSTI)

    Yi Hua Ma; Natalie Pomerantz; Chao-Huang Chen

    2008-09-30T23:59:59.000Z

    The effect of H{sub 2}S poisoning on Pd, Pd/Cu, and Pd/Au alloy composite membranes prepared by the electroless deposition method on porous Inconel supports was investigated to provide a fundamental understanding of the durability and preparation of sulfur tolerant membranes. X-ray photoelectron spectroscopy (XPS) studies showed that the exposure of pure Pd to 50 ppm H{sub 2}S/H{sub 2} mixtures caused bulk sulfide formation at lower temperatures and surface sulfide formation at higher temperatures. Lower temperatures, longer exposure times, and higher H{sub 2}S concentrations resulted in a higher degree of sulfidation. In a Pd membrane, the bulk sulfide formation caused a drastic irrecoverable H{sub 2} permeance decline and an irreparable loss in selectivity. Pd/Cu and Pd/Au alloy membranes exhibited permeance declines due to surface sulfide formation upon exposure to 50 ppm H{sub 2}S/H{sub 2} gas mixtures. However in contrast to the pure Pd membrane, the permeances of the Pd/Cu and Pd/Au alloy membranes were mostly recovered in pure H{sub 2} and the selectivity of the Pd alloy layers remained essentially intact throughout the characterization in H{sub 2}, He and H{sub 2}S/H{sub 2} mixtures which lasted several thousand hours. The amount of irreversible sulfur poisoning decreased with increasing temperature due to the exothermicity of H{sub 2}S adsorption. Longer exposure times increased the amount of irreversible poisoning of the Pd/Cu membrane but not the Pd/Au membrane. Pd/Au coupon studies of the galvanic displacement method showed that higher Au{sup 3+} concentrations, lower pH values, higher bath temperatures and stirring the bath at a rate of 200 rpm yielded faster displacement rates, more uniform depositions, and a higher Au content within the layers. While 400 C was found to be sufficient to form a Pd/Au alloy on the surface, high temperature X-ray diffraction (HTXRD) studies showed that even after annealing between 500-600 C, the Pd/Cu alloys could have part or all of the surface in the less sulfur resistant {beta} phase.

  11. AK Hartmann, Thermodynamik und Statistische Physik 103 Auf Koexistenzkurve p(T): 1(T, p(T)) -2(T, p(T)) = 0

    E-Print Network [OSTI]

    Hartmann, Alexander K.

    AK Hartmann, Thermodynamik und Statistische Physik 103 26.1.2006 Auf Koexistenzkurve p(T): µ1(T, p(T)) - µ2(T, p(T)) = 0 totale Ableitung d dT = 0: 0 ! = dµ1(T) dT - dµ2(T) dT = µ1 T p - µ2 T p + µ1 p T - µ2 p T dp dT = 1 N S - 1 N V dp dT (S = 0, V = 0) dp dT = S V = Ql TV (14.3) Gleichung von Clausius

  12. Bulk FePt/Fe3Pt nanocomposite magnets prepared by spark plasma Chuan-Bing Rong, Vikas Nandwana, Narayan Poudyal, and J. Ping Liua

    E-Print Network [OSTI]

    Liu, J. Ping

    Bulk FePt/Fe3Pt nanocomposite magnets prepared by spark plasma sintering Chuan-Bing Rong, Vikas nanocomposite magnets from nano- particles remains a great challenge. Spark plasma sintering SPS is known as one; published online 27 April 2007 FePt/Fe3Pt bulk nanocomposite magnets have been prepared by the spark plasma

  13. Pd-vacancy complex in Ge: TDPAC and ab initio study

    SciTech Connect (OSTI)

    Abiona, Adurafimihan A.; Kemp, Williams; Timmers, Heiko [School of Physical, Environmental and Mathematical Sciences, The University of New South Wales, UNSW Canberra, PO Box 7916, Canberra BC 2610 (Australia)

    2014-02-21T23:59:59.000Z

    Low temperature metal-induced-crystallized germanium is a promising alternative for silicon in Complementary Metal-Oxide-Semiconductor (CMOS) technology. Palladium (Pd) is one of the metals suitable for inducing the low temperature crystallization. It is not certain, how residual Pd atoms are integrated into the Ge lattice. Therefore, time-different ?-? perturbed angular correlation (TDPAC) technique using the {sup 100}Pd(?{sup 100}Rh) nuclear probe has been applied to study the hyperfine interactions of this probe in single crystalline undoped Ge. A Pd-vacancy (Pd-V) complex with a unique interaction frequency of 8.4(2) Mrad/s has been identified. The Pd-V complex has been measured to have a maximum fraction after annealing at 350 °C. Density functional theory calculations have confirmed that the Pd-V complex may have the split-vacancy configuration in Ge, in contrast to the full-vacancy configuration observed in Si.

  14. Design of graphene sheets-supported Pt catalyst layer in PEM...

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

    graphene sheets-supported Pt catalyst layer in PEM fuel cells. Design of graphene sheets-supported Pt catalyst layer in PEM fuel cells. Abstract: A series of cathodes using Pt...

  15. Care of a cardiac pt on mechanical ventilation

    E-Print Network [OSTI]

    Kay, Mark A.

    Care of a cardiac pt on mechanical ventilation CVICU New Hires Orientation Day 2 Winnie Yung, RN, MN #12;Outline · Physiology of breathing · Terminology · Intubation · Mode of mechanical ventilation· Mode of mechanical ventilation · Nursing care of a vented pt · Nursing care of a vented single

  16. Ordinary versus PT-symmetric ?³ quantum field theory

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

    Bender, Carl M.; Branchina, Vincenzo; Messina, Emanuele

    2012-04-01T23:59:59.000Z

    A quantum-mechanical theory is PT-symmetric if it is described by a Hamiltonian that commutes with PT, where the operator P performs space reflection and the operator T performs time reversal. A PT-symmetric Hamiltonian often has a parametric region of unbroken PT symmetry in which the energy eigenvalues are all real. There may also be a region of broken PT symmetry in which some of the eigenvalues are complex. These regions are separated by a phase transition that has been repeatedly observed in laboratory experiments. This paper focuses on the properties of a PT-symmetric ig?³ quantum field theory. This quantum field theory is the analog of the PT-symmetric quantum-mechanical theory described by the Hamiltonian H=p²+ix³, whose eigenvalues have been rigorously shown to be all real. This paper compares the renormalization group properties of a conventional Hermitian g?³ quantum field theory with those of the PT-symmetric ig?³ quantum field theory. It is shown that while the conventional g?³ theory in d=6 dimensions is asymptotically free, the ig?³ theory is like a g?? theory in d=4 dimensions; it is energetically stable, perturbatively renormalizable, and trivial.

  17. Impact of surface roughness of Au core in Au/Pd coreeshell nanoparticles toward formic acid oxidation e Experiment and

    E-Print Network [OSTI]

    Liu, Fuqiang

    Impact of surface roughness of Au core in Au/Pd coreeshell nanoparticles toward formic acid h t s Unique Au/Pd coreeshell nanoparticles were synthesized via a galvanic replacement of Cu by Pd on hollow Au. Au/Pd coreeshell nanoparticles with smooth Au surface by adding Na2SO3 demonstrated highly

  18. Composition-Mediated Order-Disorder Transformation in FePt Nanoparticles

    SciTech Connect (OSTI)

    Johnston-Peck, Aaron C [ORNL; Cullen, David A [ORNL; Tracy, Joseph B [North Carolina State University

    2013-01-01T23:59:59.000Z

    Thumbnail image of graphical abstract Heat-treated alloy FePt nanoparticles transform into L10 FePt and mixed L10/L12 FePt3 intermetallic phases. Enrichment in Pt in some nanoparticles, rather than intrinsic thermodynamic effects, drives phase segregation. FePt nanoparticles of uniform, equimolar composition are expected to transform into phase-pure, highly ordered L10 FePt nanoparticles.

  19. Reactivity and stability of platinum and platinum alloy catalysts toward the oxygen reduction reaction

    E-Print Network [OSTI]

    Calvo, Sergio Rafael

    2009-05-15T23:59:59.000Z

    Density functional theory (DFT) is used to study the reactivity of Pt and Pt-M (M: Pd, Co, Ni, V, and Rh) alloy catalysts towards the oxygen reduction reaction (ORR) as a function of the alloy overall composition and surface atomic distribution...

  20. PHYSICAL REVIEW B 84, 214110 (2011) Ordered phases in ruthenium binary alloys from high-throughput first-principles calculations

    E-Print Network [OSTI]

    Hart, Gus

    2011-01-01T23:59:59.000Z

    -oxidation, CO electro-oxidation, and methane steam reforming).7 Experimental examples of this potential are the use of a PdRu catalyst as the anode of ethanol alkaline fuel cells8 and of Pt-Ru-Ni and Pt

  1. Graphdiyne as a Promising Substrate for Stabilizing Pt Nanoparticle Catalyst

    E-Print Network [OSTI]

    Lin, Zheng-Zhe

    2015-01-01T23:59:59.000Z

    At present, Pt nanoparticle catalysts in fuel cells suffer from aggregation and loss of chemical activity. In this work, graphdiyne, which has natural porous structure, was proposed as substrate with high adsorption ability to stabilize Pt nanoparticles. Using multiscale calculations by ab initio method and the ReaxFF potential, geometry optimizations, molecular dynamics simulations, Metropolis Monte Carlo simulations and minimum energy paths calculations were performed to investigate the adsorption energy and the rates of desorption and migration of Pt nanoparticles on graphdiyne and graphene. According to the comparison between graphdiyne and graphene, it was found that the high adsorption ability of graphdiyne can avoid Pt nanoparticle migration and aggregation on substrate. Then, simulations indicated the potential catalytic ability of graphdiyne-Pt-nanoparticle system to the oxygen reduction reaction in fuel cells. In summary, graphdiyne should be an excellent material to replace graphite or amorphous ca...

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

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

    the Impact of Pt Contamination on Cu-Zeolite SCR Catalyst Performance Mitigation of the Impact of Pt Contamination on Cu-Zeolite SCR Catalyst Performance Investigates operating...

  3. Highlights 119 El nmero est dedicado al Dr. Omar Solorza Feria, Profesor Titular del Depto. de Qumica, por su

    E-Print Network [OSTI]

    . Solorza-Feria, Evaluation of Ru x W y Se z Catalyst as a Cathode Electrode in a Polymer Electrolyte and Characterization of Pd 0.5 Ni x Se (0.5-x) Electrocatalyst for Oxygen Reduction Reaction in Acid Media. Int. J-Feria, Low Pt content on Pd 45 Pt 5 Sn 50 cathode catalyst for PEM fuel cells. J. Power Sources, In press

  4. Approved Module Information for AM20PD, 2014/5 Module Title/Name: Probability Distributions Module Code: AM20PD

    E-Print Network [OSTI]

    Neirotti, Juan Pablo

    Code: AM20PD School: Engineering and Applied Science Module Type: Standard Module New Module? No Module? Not Specified Module Dependancies Pre-requisites: Transition Mathematics (AM10TM). Statistics and ProbabilityApproved Module Information for AM20PD, 2014/5 Module Title/Name: Probability Distributions Module

  5. Thermally stable perpendicular magnetic anisotropy features of [Co/Pd]{sub m} multilayer matrix integrated with [CoO/Pd]{sub n} bottom layer

    SciTech Connect (OSTI)

    Lee, JaBin; An, GwangGuk; Yang, SeungMo; Hong, JinPyo, E-mail: jphong@hanyang.ac.kr [Novel Functional Materials and Device Laboratory, Department of Physics, The Research Institute for Natural Science, Hanyang University, Seoul 133-791 (Korea, Republic of); Chung, WooSeong [Nano Quantum Electronics Laboratory, Department of Electronics and Computer Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2014-01-13T23:59:59.000Z

    We evaluated the perpendicular magnetic anisotropy (PMA) features of a hybrid [CoO/Pd]{sub 2}/[Co/Pd]{sub 7} multilayer (ML) matrix under annealing in which the [CoO/Pd]{sub 2} bottom layer was inserted. Annealing allowed for the diffusion of oxygen atoms existing in the inserted [CoO/Pd]{sub 2} layer, leading to an atomic structural reconfiguration event. The hybrid matrix was crucial to result in a higher effective anisotropy energy (3.40 Merg/cc) than an ordinary [Co/Pd]{sub 7} ML matrix (1.25 Merg/cc) under annealing at 450?°C. X-ray photoelectron spectroscopy confirmed the presence of Co-O bonding states and annealing dependent oxygen atom diffusion. The possible nature of the enhanced PMA features is discussed.

  6. Improving the phase stability and oxidation resistance of B-NiAl

    SciTech Connect (OSTI)

    Brammer, Travis

    2011-08-15T23:59:59.000Z

    High temperature alloys are essential to many industries that require a stable material to perform in harsh oxidative environments. Many of these alloys are suited for specific applications such as jet engine turbine blades where most other materials would either melt or oxidize and crumble (1). These alloys must have a high melting temperature, excellent oxidation resistance, good creep resistance, and decent fracture toughness to be successfully used in such environments. The discovery of Ni based superalloys in the 1940s revolutionized the high temperature alloy industry and there has been continued development of these alloys since their advent (2). These materials are capable of operating in oxidative environments in the presence of combustion gases, water vapor and at temperatures around 1050 C. Demands for increased f uel efficiency, however, has highlighted the need for materials that can be used under similar atmospheres and at temperatures in excess of 1200 C. The current Ni based superalloys are restricted to lower temperatures due to the presence of a number of low melting phases that result in softening of the alloys above 1000 C. Therefore, recent research has been aimed at exploring and developing newer alloy systems that can meet the escalating requirements. This thesis comprises a part of such an effort. The motivation of this work is to develop a novel high temperature alloy system that shows improved performance at higher temperatures than the currently employed alloys. The desired alloy should be in accordance with the requirements established in the National Energy Technology Laboratory (NETL) FutureGen program having an operating temperature around 1300 C. Alloys based on NiAl offer significant potential payoffs as structural materials in gas turbine applications due to a unique range of physical and mechanical properties. Alloying additions to NiAl could be used to further improve the pertinent properties that currently limit this system from replacing Ni based superalloys. Modifications to NiAl were explored to increase the phase stability and oxidation resistance which would allow these alloys to be used at even higher temperatures yielding greater efficiencies. The extended Miedema model was an effective tool that screened all of the potential phase space for ternary substitutions to NiAl and found the few potential systems worth further investigation. After production of the alloys it was determined that Ir, Rh, and Pd were the top candidates for substitution on Ni site up to 12 at%. The melting temperature of NiAl could be increased as much as 150 C with 12 at% Ir and 130 C with 12 at% Rh substitution. Pall adium on the other hand decreased the melting temperature by 50 C at the 12 at% substitution level. The grain size was found to have a profound influence on the oxidation resistance. Both Ir and Rh substitutions resulted in finer grain sizes compared to Pd substitutions or base NiAl. The grain size increased drastically during high temperature annealing with the PGM substitutions hindering grain growth only slightly. However, the addition of 0.05 at% Hf limited the grain growth dramatically during high temperature annealing. NiAl inherently has respectable oxidation resistance up to 1100 C. It was found through experimental testing that both Ir and Rh substitutions improve the oxidation resistance of NiAl at ultra-high temperatures with Ir performing the best. Both PGM substitutions decreased the growth rate as well as forming a more adherent oxide scale. Pd substitutions appeared to have a negligible effect to the oxidation resistance of NiAl. Hafnium addition of 0.05 at% was found to decrease the oxidation rate as well as increase the scale adherence. The combination of both Ir substitution (6-9 at%) and Hf addition (0.05 at%) produced the alloy with the best oxidation resistance. Although improvements in phase stability and oxidation resistance have been made to the NiAl system, more development and testing are still needed. Two major issues yet to be resolved are the low fracture toughn

  7. Imaging Chemical Aggregation of Ni/NiO Particles from Reduced...

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

    from Reduced NiO-YSZ. Abstract: Energy dispersive X-ray spectroscopy (EDS) mapping of nickel oxide yttria-stabilized zirconia (NiO-YSZ) was carried out after various hydrogen...

  8. Surface characterization of Pd/Al2O3 sorbents for mercury capture from fuel gas

    SciTech Connect (OSTI)

    Baltrus, J.P.; Granite, E.J.; Stanko, D.C.; Pennline, H.W.

    2008-01-01T23:59:59.000Z

    The surface composition of a series of Pd/alumina sorbents has been characterized to better understand the factors influencing their ability to adsorb mercury from fuel gas. Both a temperature effect and a dispersion effect were found. Maximum adsorption of Hg occurred at the -lowest temperature tested, 204°C, and decreased with increasing temperatures. Maximum adsorption of Hg on a per-atom basis of Pd is observed at low loadings of Pd ( < 8.5% Pd) due to better dispersion of Pd at those loadings; a change in its partitioning occurs at higher loadings. The presence of H2S 'in the fuel gas acts to promote the adsorption of Hg through its association with Hg in the Pd lattice.

  9. Surface characterization of Pd/Al2O3 sorbents for mercury capture from fuel gas

    SciTech Connect (OSTI)

    Baltrus, J.P.; Granite, E.J.; Stanko, D.C.; Pennline, H.W.

    2008-09-01T23:59:59.000Z

    The surface composition of a series of Pd/alumina sorbents has been characterized to better understand the factors influencing their ability to adsorb mercury from fuel gas. Both a temperature effect and a dispersion effect were found. Maximum adsorption of Hg occurred at the lowest temperature tested, 2048C, and decreased with increasing temperatures. Maximum adsorption of Hg on a per-atom basis of Pd is observed at low loadings of Pd (58.5% Pd) due to better dispersion of Pd at those loadings; a change in its partitioning occurs at higher loadings. The presence of H2S in the fuel gas acts to promote the adsorption of Hg through its association with Hg in the Pd lattice.

  10. Electrochemical Stability of Nanometer-Scale Pt Particles in Acidic Environments

    E-Print Network [OSTI]

    Ceder, Gerbrand

    the stability of individual Pt nanoparticles as a function of applied potential. We combine this experimentalElectrochemical Stability of Nanometer-Scale Pt Particles in Acidic Environments Lei Tang of Pt as a function of particle size and potential. Both approaches clearly show that smaller Pt

  11. au-pd bimetallic nanoparticles: Topics by E-print Network

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

    in the function of bimetallic alloys or nanoparticles whose Henkelman, Graeme 3 NANO EXPRESS Open Access AuPd core-shell nanoparticles with varied hollow Energy Storage,...

  12. Synergistic Catalysis between Pd and Fe in Gas Phase Hydrodeoxygenation of m-Cresol

    SciTech Connect (OSTI)

    Hong, Yongchun; Zhang, He; Sun, Junming; Karim, Ayman M.; Hensley, Alyssa; Gu, Meng; Engelhard, Mark H.; McEwen, Jean-Sabin; Wang, Yong

    2014-10-31T23:59:59.000Z

    In this work, a series of Pd/Fe2O3 catalysts were synthesized, characterized, and evaluated for the hydrodeoxygenation (HDO) of m-cresol. It was found that the addition of Pd remarkably promotes the catalytic activity of Fe while the product distributions resemble that of monometallic Fe catalyst, showing high selectivity towards the production of toluene (C-O cleavage without saturation of aromatic ring and C-C cleavage). Reduced catalysts featured with Pd patches on the top of reduced Fe nanoparticle surface, and the interaction between Pd and Fe was further confirmed using X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM) and X-ray absorption near edge fine structure (XANES). A possible mechanism, including Pd assisted H2 dissociation and Pd facilitated stabilization of metallic Fe surface as well as Pd enhanced product desorption, is proposed to be responsible for the high activity and HDO selectivity in Pd-Fe catalysts. The synergic catalysis derived from Pd-Fe interaction found in this work was proved to be applicable to other precious metal promoted Fe catalysts, providing a promising strategy for future design of highly active and selective HDO catalysts.

  13. Monopole Strength in Ni-58

    E-Print Network [OSTI]

    Youngblood, David H.; Lui, YW.

    1991-01-01T23:59:59.000Z

    PHYSICAL REVIEW C VOLUME 44, NUMBER 5 Monopole strength in Ni NOVEMBER 1991 D. H. Youngblood and Y.-W. Lui Cyclotron Institute, Texas AdkM Uni Uersi ty, College Station, Texas 77843 (Received 20 June 1991) Differential cross-section data from... strength is locat- ed nearer the quadrupole (for Ca [3] and Si [4] at vir- tually the same energy). Only two reports of substantial strength in lighter nuclei are in the literature. Lui et al. [4] reported 66%%uo of the EO energy-weighted sum rule...

  14. Electron-Transport Properties of Amorphous (Zr0.64ni0.36)1-Xalx Alloys

    E-Print Network [OSTI]

    BHATNAGAR, AK; PAN, R.; Naugle, Donald G.

    1989-01-01T23:59:59.000Z

    PHYSICAL REVIEW B VOLUME 39, NUMBER 17 15 JUNE 1989-I Electron transport properties of amorphous (Zro 64Nio 36), ?Al?alloys A. K. Bhatnagar, ' R. Pan, and D. G. Naugle Department ofPhysics, Texas Ad'cM Uniuersity, College Station, Texas 77843...-4242 (Received 28 November 1988; revised manuscript received 16 March 1989) Measurements of the electrical resistivity p(T), thermopower S(T), and Hall coe%cient RH for a series of rapidly quenched Zr-Ni-Al alloys are reported for concentrations from x =0 to 0...

  15. Correlation of Pt-Re Surface Properties with Reaction Pathways...

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

    with Reaction Pathways for the Aqueous-Phase Reforming of Glycerol. Abstract: The surface properties of Pt-Re catalytic nano-particles supported on carbon following exposure to a...

  16. Thermoelectric effect in very thin film Pt/Au thermocouples

    SciTech Connect (OSTI)

    Salvadori, M.C.; Vaz, A.R.; Teixeira, F.S.; Cattani, M.; Brown,I.G.

    2006-01-10T23:59:59.000Z

    The thickness dependence of the thermoelectric power of Pt films of variable thickness on a reference Au film has been determined for the case when the Pt film thickness, t, is not large compared to the charge carrier mean free path, {ell}, that is, t/{ell}. Pt film thicknesses down to 2.2 nm were investigated. We find that {Delta}S{sub F} = S{sub B}-S{sub F} (where S{sub B} and S{sub F} are the thermopowers of the Pt bulk and film, respectively) does not vary linearly as 1/t as is the case for thin film thermocouples when the film thickness is large compared to the charge carrier mean free path.

  17. anketo chosa ni: Topics by E-print Network

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

    Summary: Recent research shows that the resistance switching characteristics of NiO thin film, in combinations conversion into NiSi using Ni-AMD, and discuss the chemistry of...

  18. anteisei ni kansuru: Topics by E-print Network

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

    Summary: Recent research shows that the resistance switching characteristics of NiO thin film, in combinations conversion into NiSi using Ni-AMD, and discuss the chemistry of...

  19. atsumitsu katei ni: Topics by E-print Network

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

    Summary: Recent research shows that the resistance switching characteristics of NiO thin film, in combinations conversion into NiSi using Ni-AMD, and discuss the chemistry of...

  20. arikata ni kansuru: Topics by E-print Network

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

    Summary: Recent research shows that the resistance switching characteristics of NiO thin film, in combinations conversion into NiSi using Ni-AMD, and discuss the chemistry of...

  1. ataeru eikyo ni: Topics by E-print Network

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

    Summary: Recent research shows that the resistance switching characteristics of NiO thin film, in combinations conversion into NiSi using Ni-AMD, and discuss the chemistry of...

  2. aisorui ni taisuru: Topics by E-print Network

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

    Summary: Recent research shows that the resistance switching characteristics of NiO thin film, in combinations conversion into NiSi using Ni-AMD, and discuss the chemistry of...

  3. anzensei ni kansuru: Topics by E-print Network

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

    Summary: Recent research shows that the resistance switching characteristics of NiO thin film, in combinations conversion into NiSi using Ni-AMD, and discuss the chemistry of...

  4. The beta-delayed neutron emission in 78Ni region

    E-Print Network [OSTI]

    I. N. Borzov

    2004-09-09T23:59:59.000Z

    A systematic study of the total $\\beta$-decay half-lives and $\\beta$-delayed neutron emission probabilities is performed. The $\\beta$-strength function is treated within the self-consistent density-functional + continuum-QRPA framework including the Gamow-Teller and first-forbidden transitions. The experimental total $\\beta$-decay half-lives for the Ni isotopes with $A\\leq$76 are described satisfactorily. The half-lives predicted from $A$=70 up to $A$=86 reveal fairly regular $A$-behaviour which results from simultaneous account for the Gamow-Teller and first-forbidden transitions. For $Z\\approx$ 28 nuclei, a suppression of the delayed neutron emission probability is found when the $N$=50 neutron closed shell is crossed. The effect originates from the high-energy first-forbidden transitions to the states outside the $Q_{\\beta} - S_n$-window in the daughter nuclei. PACS numbers: 23.40.Bw,21.60.Jz,25.30.Pt,26.30.+k

  5. The beta-delayed neutron emission in 78Ni region

    E-Print Network [OSTI]

    Borzov, I N

    2004-01-01T23:59:59.000Z

    A systematic study of the total $\\beta$-decay half-lives and $\\beta$-delayed neutron emission probabilities is performed. The $\\beta$-strength function is treated within the self-consistent density-functional + continuum-QRPA framework including the Gamow-Teller and first-forbidden transitions. The experimental total $\\beta$-decay half-lives for the Ni isotopes with $A\\leq$76 are described satisfactorily. The half-lives predicted from $A$=70 up to $A$=86 reveal fairly regular $A$-behaviour which results from simultaneous account for the Gamow-Teller and first-forbidden transitions. For $Z\\approx$ 28 nuclei, a suppression of the delayed neutron emission probability is found when the $N$=50 neutron closed shell is crossed. The effect originates from the high-energy first-forbidden transitions to the states outside the $Q_{\\beta} - S_n$-window in the daughter nuclei. PACS numbers: 23.40.Bw,21.60.Jz,25.30.Pt,26.30.+k

  6. The PD algorithm: a simulation based partitioning algorithm for ATPG

    E-Print Network [OSTI]

    Lin, Shyh-Horng

    1993-01-01T23:59:59.000Z

    is shown in Figure 17 3(d). Figure 3(d) is very similar to Figure 3(b) but the line f fans out to the gate G8 which is also driven by control line b. There are no circuit graph dommators of the faulty site in this case. Before any attempt to propagate... performs the following tasks. 1. Perform logic calculation. 2. Based on the output value, assign necessary input values. 3. Maintain all stacks. 4. Detect tf there is a conflict, OS dd D' d~ O d(I Sdd dd S I 7 7 P I 4~17 d~ pd PO ~ dd D4 dd...

  7. PT-invariant one-dimensional Coulomb problem

    E-Print Network [OSTI]

    Anjana Sinha; Rajkumar Roychoudhury

    2002-07-23T23:59:59.000Z

    The one-dimensional Coulomb-like potential with a real coupling constant beta, and a centrifugal-like core of strength G = alpha^2 - {1/4}, viz. V(x) = {alpha^2 - (1/4)}/{(x-ic)^2} + beta/|x-ic|, is discussed in the framework of PT-symmetry. The PT-invariant exactly solvable model so formed, is found to admit a double set of real and discrete energies, numbered by a quasi-parity q = +/- 1.

  8. $\\cal{PT}$ symmetric models with nonlinear pseudo supersymmetry

    E-Print Network [OSTI]

    A. Sinha; P. Roy

    2005-05-30T23:59:59.000Z

    By applying the higher order Darboux algorithm to an exactly solvable non Hermitian ${\\cal{PT}}$ symmetric potential, we obtain a hierarchy of new exactly solvable non Hermitian ${\\cal{PT}}$ symmetric potentials with real spectra. It is shown that the symmetry underlying the potentials so generated and the original one is {\\it nonlinear pseudo supersymmetry}. We also show that this formalism can be used to generate a larger class of new solvable potentials when applied to non Hermitian systems.

  9. Coupled Oscillator Systems Having Partial PT Symmetry

    E-Print Network [OSTI]

    Beygi, Alireza; Bender, Carl M

    2015-01-01T23:59:59.000Z

    This paper examines chains of $N$ coupled harmonic oscillators. In isolation, the $j$th oscillator ($1\\leq j\\leq N$) has the natural frequency $\\omega_j$ and is described by the Hamiltonian $\\frac{1}{2}p_j^2+\\frac{1}{2}\\omega_j^2x_j^2$. The oscillators are coupled adjacently with coupling constants that are purely imaginary; the coupling of the $j$th oscillator to the $(j+1)$st oscillator has the bilinear form $i\\gamma x_jx_{j+1}$ ($\\gamma$ real). The complex Hamiltonians for these systems exhibit {\\it partial} $\\mathcal{PT}$ symmetry; that is, they are invariant under $i\\to-i$ (time reversal), $x_j\\to-x_j$ ($j$ odd), and $x_j\\to x_j$ ($j$ even). [They are also invariant under $i\\to-i$, $x_j\\to x_j$ ($j$ odd), and $x_j\\to- x_j$ ($j$ even).] For all $N$ the quantum energy levels of these systems are calculated exactly and it is shown that the ground-state energy is real. When $\\omega_j=1$ for all $j$, the full spectrum consists of a real energy spectrum embedded in a complex one; the eigenfunctions correspondi...

  10. Waste Heat Energy Harvesting Using Olsen Cycle on PZN-5.5PT Single Crystals

    E-Print Network [OSTI]

    McKinley, Ian Meeker; Kandilian, Razmig; Pilon, Laurent

    2012-01-01T23:59:59.000Z

    1 µ m thick Au 0.68 Pd 0.32 electrode. (a) (b) Displacement,1 µ m thick Au 0.68 Pd 0.32 electrodes having ? =16,951 kg/m

  11. Electrodeposited NiCo/Cu Superlattices

    SciTech Connect (OSTI)

    Safak, M.; Alper, M. [Department of Physics, Faculty of Science and Literature, University of Uludag, Goeruekle, Bursa (Turkey)

    2007-04-23T23:59:59.000Z

    NiCo/Cu superlattices were electrodeposited on polycrystalline Cu substrates from a single electrolyte under potentiostatic control. The X-ray diffraction (XRD) patterns showed that NiCo/Cu superlattices have the same crystal structure and texture as in their substrates. The films exhibited giant magnetoresistance (GMR) or anisotropic magnetoresistance (AMR), depending on the Cu layer thicknesses.

  12. Interfacial oxygen migration and its effect on the magnetic anisotropy in Pt/Co/MgO/Pt films

    SciTech Connect (OSTI)

    Chen, Xi; Feng, Chun, E-mail: fengchun@ustb.edu.cn, E-mail: ghyu@mater.ustb.edu.cn; Liu, Yang; Jiang, Shaolong; Hua Li, Ming; Hua Yu, Guang, E-mail: fengchun@ustb.edu.cn, E-mail: ghyu@mater.ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Long Wu, Zheng [Analytical and Testing Center, Beijing Normal University, Beijing 100875 (China); Yang, Feng [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249 (China)

    2014-02-03T23:59:59.000Z

    This paper reports the interfacial oxygen migration effect and its induced magnetic anisotropy evolution in Pt/Co/MgO/Pt films. During depositing the MgO layer, oxygen atoms from the MgO combine with the neighboring Co atoms, leading to the formation of CoO at the Co/MgO interface. Meanwhile, the films show in-plane magnetic anisotropy (IMA). After annealing, most of the oxygen atoms in CoO migrate back to the MgO layer, resulting in obvious improvement of Co/MgO interface and the enhancement of effective Co-O orbital hybridization. These favor the evolution of magnetic anisotropy from IMA to perpendicular magnetic anisotropy (PMA). The oxygen migration effect is achieved by the redox reaction at the Co/MgO interface. On the contrary, the transfer from IMA to PMA cannot be observed in Pt/Co/Pt films due to the lack of interfacial oxygen migration.

  13. Indirect heating of Pt by non-equilibrium electrons in Au in a nanoscale Pt/Au bilayer

    E-Print Network [OSTI]

    Cahill, David G.

    -line equivalent-circuit. For optical exciation of either the Pt or Au side of the bilayer, the majority of energy excitations which are then driven out of thermal equilibrium with the vibrations of the atomic lattice.1

  14. Underpotential deposition of Ag adlayers on Pt(111): Structures and determination of O{sub 2} adsorption on Pt(111)

    SciTech Connect (OSTI)

    Marinkovic, N.S.; Wang, J.X.; Adzic, R.R.

    1997-09-01T23:59:59.000Z

    The structure of Ag adlayers deposited at underpotentials in sulfuric acid on Pt(111), and the inhibition of O{sub 2} reduction they cause, have been studied using grazing incident angle x-ray diffraction measurements, as well as linear sweep voltammetry and in situ FTIR spectroscopy. Ag forms a hexagonal incommensurate bilayer, with two mutually commensurate monolayers. It is aligned with the Pt(111) substrate, although slightly expanded. The first monolayer has a commensurate (1 x 1) structure. A second layer causes a restructuring of the first monolayer. Deposition of each monolayer is associated with one voltammetry Peak. A complete inhibition of O{sub 2} reduction on Pt(111) has been observed upon deposition of both, Ag monolayer and bilayer. Analysis of the inhibition of O{sub 2} reduction as a function of the Ag coverage shows that during reduction O{sub 2} adsorbs in a bridge configuration on Pt(111).

  15. $\\mathcal{PT}$-systems without parity symmetry: topological states, hidden symmetry, and the $\\mathcal{PT}$ phase diagram

    E-Print Network [OSTI]

    Joglekar, Yogesh N

    2015-01-01T23:59:59.000Z

    $\\mathcal{PT}$-symmetric systems, until now, have been characterized by a real, parity-symmetric, kinetic Hamiltonian and a non-Hermitian, balanced gain-loss potential. We present a new class of discrete models in which the tunneling Hamiltonian is not parity-symmetric, and yet the models have a nonzero $\\mathcal{PT}$-breaking threshold in presence of a pair of gain-loss impurities $\\pm i\\gamma$ located at reflection-symmetric sites. We uncover a hidden symmetry that is instrumental to the finite threshold strength. We show that such models have topological edge-states that remain robust in the $\\mathcal{PT}$-broken phase. Our predictions substantially broaden possible realizations of a $\\mathcal{PT}$ system, particularly in optical waveguide arrays or coupled microstructures, by eliminating the parity-symmetry constraint.

  16. Nanoscale structural heterogeneity in Ni-rich half-Heusler TiNiSn

    SciTech Connect (OSTI)

    Douglas, Jason E., E-mail: jedouglas@mrl.ucsb.edu; Pollock, Tresa M. [Materials Department, University of California, Santa Barbara, California 93106 (United States); Materials Research Laboratory, University of California, Santa Barbara, California 93106 (United States); Chater, Philip A. [Diamond Light Source, Chilton, Oxfordshire OX11 0DE (United Kingdom); Brown, Craig M. [Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Department of Chemical Engineering, University of Delaware, Newark, Delaware 19716 (United States); Seshadri, Ram [Materials Department, University of California, Santa Barbara, California 93106 (United States); Materials Research Laboratory, University of California, Santa Barbara, California 93106 (United States); Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106 (United States)

    2014-10-28T23:59:59.000Z

    The structural implications of excess Ni in the TiNiSn half-Heusler compound are examined through a combination of synchrotron x-ray and neutron scattering studies, in conjunction with first principles density functional theory calculations on supercells. Despite the phase diagram suggesting that TiNiSn is a line compound with no solid solution, for small x in TiNi{sub 1+x}Sn there is indeed an appearance—from careful analysis of the scattering—of some solubility, with the excess Ni occupying the interstitial tetrahedral site in the half-Heusler structure. The analysis performed here would point to the excess Ni not being statistically distributed, but rather occurring as coherent nanoclusters. First principles calculations of energetics, carried out using supercells, support a scenario of Ni interstitials clustering, rather than a statistical distribution.

  17. Purification and Characterization of [NiFe]-Hydrogenase of Shewanella...

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

    Purification and Characterization of NiFe-Hydrogenase of Shewanella oneidensis MR-1. Purification and Characterization of NiFe-Hydrogenase of Shewanella oneidensis MR-1....

  18. al ni shape: Topics by E-print Network

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

    NiAl NANOLAMINATES . Open Access Theses and Dissertations Summary: ??To characterize the self-propagating, high-temperature exothermic alloying reactions of NiAl nanoscaled...

  19. Infrared vibrational studies of CO adsorption on Cu/Pt(lll) and CuPt(111) Jo& A. Rodriguez,@ Charles M. Truong, and D. Wayne Goodmanb)

    E-Print Network [OSTI]

    Goodman, Wayne

    Infrared vibrational studies of CO adsorption on Cu/Pt(lll) and CuPt(111) surfaces Jo& A. Rodriguez supported on Pt ( 111) has been studied using infrared reflection absorption spectroscopy (IRAS). Our results indicate that the infrared intensities of adsorbed CO are not representative of the relative

  20. Hydrogen production from methanol decomposition over Pt/Al2O3 and ceria promoted Pt/Al2O3 catalysts

    E-Print Network [OSTI]

    Gulari, Erdogan

    Hydrogen production from methanol decomposition over Pt/Al2O3 and ceria promoted Pt/Al2O3 catalysts-based catalysts in the production of hydrogen from methanol through catalytic decomposition rights reserved. Keywords: Methanol decomposition; Pt/alumina; Ceria; Hydrogen; PEM fuel cell 1

  1. SEARCH FOR CHARGED -PARTICLE d -d FUSION PRODUCTS IN AN ENCAPSULATED Pd THIN FILM

    E-Print Network [OSTI]

    Neuhauser, Barbara

    SEARCH FOR CHARGED - PARTICLE d - d FUSION PRODUCTS IN AN ENCAPSULATED Pd THIN FILM E. López, B the possibility of deuteron-deuteron (d-d) fusion at room temperature within the bulk palladium electrode / Pd ratio exceeding 100 %. The palladium film was encapsulated with a thin layer of silicon nitride

  2. Spatial Distribution Of Cerium Valence In Model Planar Pd/Ce0...

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

    Distribution Of Cerium Valence In Model Planar PdCe0.7Zr0.3O2 Catalysts. Spatial Distribution Of Cerium Valence In Model Planar PdCe0.7Zr0.3O2 Catalysts. Abstract: The spatial...

  3. PD Dr. Martin Stetter, Siemens AG 1 Statistische und neuronale Lernverfahren

    E-Print Network [OSTI]

    Popeea, Corneliu - Chair for Foundations of Software Reliability and Theoretical Computer Science

    PD Dr. Martin Stetter, Siemens AG 1 Statistische und neuronale Lernverfahren Martin Stetter SS 2003, Siemens AG 2 Behandelte Themen 0. ,,Motivation": Lernen in Statistik und Biologie 1-Regression 4. Bayes-Belief-Netze Statistische und neuronale Lernverfahren #12;PD Dr. Martin Stetter, Siemens AG

  4. PD Dr. Martin Stetter, Siemens AG 1 Statistische und neuronale Lernverfahren

    E-Print Network [OSTI]

    Popeea, Corneliu - Chair for Foundations of Software Reliability and Theoretical Computer Science

    PD Dr. Martin Stetter, Siemens AG 1 Statistische und neuronale Lernverfahren Martin Stetter WS 03, Siemens AG 2 Behandelte Themen 0. ,,Motivation": Lernen in Statistik und Biologie 1-Regression 4. Bayes-Belief-Netze Statistische und neuronale Lernverfahren #12;PD Dr. Martin Stetter, Siemens AG

  5. Ion channeling and TEM studies of pulse-melted Fe(Pd) alloys

    SciTech Connect (OSTI)

    Knapp, J.A.; Follstaedt, D.M.

    1983-01-01T23:59:59.000Z

    Metastable Fe(Pd) surface alloys formed by deposition of layers of Pd on (100) Fe and subsequent pulsed (approx. 70 nsec, 1.9 J/cm/sup 2/) electron beam melting into the bcc substrate have been investigated by ion backscattering/channeling and TEM. Repeated pulsed melting allowed examination of the epitaxial growth of the bcc substrate phase into the alloyed region for successively lower Pd concentrations. This procedure permitted detailed examination of the conditions for solidification with the fcc or bcc crystal structure and for metastable phase formation during rapid solidification. Bcc epitaxy is absent at Pd concentrations greater than or equal to 30 at. %, where an fcc surface layer forms. Channeling of the Pd and Fe signals was observed at Pd concentrations less than or equal to 16.5 at. %, where a single-phase, supersaturated bcc alloy is observed. At an intermediate Pd concentration of 22 to 23 at. %, both epitaxial bcc and fcc materials are formed. The observed maximum substitutional Pd concentration in the bcc phase is about a factor of 5 greater than the maximum equilibrium solid solubility.

  6. 674-SO-43, Version 3.0, SSC-PD-4045

    E-Print Network [OSTI]

    Masci, Frank

    674-SO-43, Version 3.0, SSC-PD-4045 THIS IS A PRELIMINARY DOCUMENT, the module described here may California Institute of Technology Pasadena, California #12;SSC Downlink Segment 674-SO-43, Version 3.0, SSC. ii THIS PAGE IS INTENTIONALLY LEFT BLANK #12;SSC Downlink Segment 674-SO-43, Version 3.0, SSC-PD-4045

  7. 674-SO-43, Version 3.0, SSC-PD-4044

    E-Print Network [OSTI]

    Masci, Frank

    674-SO-43, Version 3.0, SSC-PD-4044 THIS IS A PRELIMINARY DOCUMENT, the module described here may California Institute of Technology Pasadena, California #12;SSC Downlink Segment 674-SO-43, Version 3.0, SSC. ii THIS PAGE IS INTENTIONALLY LEFT BLANK #12;SSC Downlink Segment 674-SO-43, Version 3.0, SSC-PD-4044

  8. Pd and Ag metal-silicate partitioning applied to Earth differentiation and core-mantle exchange

    E-Print Network [OSTI]

    Mcdonough, William F.

    Pd and Ag metal-silicate partitioning applied to Earth differentiation and core-mantle exchange metallic sulfide and liquid silicate under plausible magma ocean conditions constrains potential core 107 Ag content and the origin of observed Pd and Ag mantle abundances. DPd metallic sulfide / silicate

  9. Thermoelastic strain in polycrystalline FePd shape memory alloy thin film Jun Hyun Han a,

    E-Print Network [OSTI]

    Thermoelastic strain in polycrystalline Fe­Pd shape memory alloy thin film Jun Hyun Han a, , Juil shape memory alloy Elastic modulus Wrinkling Thermoelastic strain in a polycrystalline Fe­Pd thin film due to shape memory effect was determined from Hooke's law using the measured residual stress

  10. Enthalpy of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys

    SciTech Connect (OSTI)

    Witusiewicz, V.T.; Sommer, F.

    2000-04-01T23:59:59.000Z

    Since the Al-Cu-Ni-Zr system is a basis for the production of bulk amorphous materials by rapid solidification techniques from the liquid state, it is of great scientific interest to determine the partial and the integral thermodynamic functions of liquid and undercooled liquid alloys. Such data, as was pointed out previously, are important in order to understand their extremely good glass-forming ability in multicomponent metallic systems as well as for processing improvements. In order to measure the thermodynamic properties of the Al-Cu-Ni-Zr quaternary, it is necessary to have reliable thermochemical data for its constituent canaries and ternaries first. In a series of articles, the authors have reported in detail the thermodynamic properties of liquid Al-Cu, Al-Ni, Cu-Ni, Cu-Zr, Al-Zr, Al-Cu-Ni, and Al-Cu-Zr alloys. This article deals with the direct calorimetric measurements of the partial and the integral enthalpies of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys and the heat capacity of liquid Ni{sub 26}Zr{sub 74}. In a subsequent article, the authors will present similar data for the liquid ternary Al-Ni-Zr and for the liquid quaternary Al-Cu-Ni-Zr alloys.

  11. Low-temperature aqueous-phase reforming of ethanol on bimetallic PdZn catalysts

    SciTech Connect (OSTI)

    Xiong, Haifeng; DelaRiva, Andrew; Wang, Yong; Dayte, Abhaya

    2015-01-01T23:59:59.000Z

    Bimetallic PdZn catalysts supported on carbon black (CB) and carbon nanotubes (CNTs) were found to be selective for CO-free H-2 production from ethanol at low temperature (250 degrees C). On Pd, the H-2 yield was low (similar to 0.3 mol H-2/mol ethanol reacted) and the CH4/CO2 ratio was high (similar to 1.7). Addition of Zn to Pd formed the intermetallic PdZn beta phase (atomic ratio of Zn to Pd is 1) with increased H-2 yield (similar to 1.9 mol H-2/mol ethanol reacted) and CH4/CO2 ratio of <1. The higher H-2 yield and low CH4 formation was related to the improved dehydrogenation activity of the L1(0) PdZn beta phase. The TOF increased with particle size and the CNTs provided the most active and selective catalysts, which may be ascribed to pore-confinement effects. Furthermore, no significant changes in either the supports or the PdZn beta particles was found after aqueous-phase reforming (APR) indicating that the metal nanoparticles and the carbon support are hydrothermally stable in the aqueous phase at elevated temperatures and pressures (>200 degrees C, 65 bar). No CO was detected for all the catalysts performed in aqueous-phase reaction, indicating that both monometallic Pd and bimetallic PdZn catalysts have high water-gas shift activity during APR. However, the yield of H-2 is considerably lower than the theoretical value of 6 H-2 per mole ethanol which is due to the presence of oxygenated products and methane on the PdZn catalysts.

  12. Conserved Correlation in PT -symmetric Systems: Scattering and Bound States

    E-Print Network [OSTI]

    Kumar Abhinav; Arun Jayannavar; P. K. Panigrahi

    2012-11-05T23:59:59.000Z

    For one-dimensional PT -symmetric systems, it is observed that the non-local product obtained from the continuity equation can be interpreted as a conserved corre- lation function. This leads to physical conclusions, regarding both discrete and continuum states of such systems. Asymptotic states are shown to have necessarily broken PT -symmetry, leading to modified scattering and transfer matrices. This yields restricted boundary conditions, e.g., in- cidence from both sides, analogous to that of the proposed PT CPA laser. The interpretation of left and right states leads to a Hermitian S-matrix, resulting in the non-conservation of the flux. This further satisfies a duality condition, identical to the optical analogues. However, the non-local conserved scalar implements alternate boundary conditions in terms of in and out states, leading to the pseudo-Hermiticity condition in terms of the scattering matrix. Interestingly, when PT -symmetry is preserved, it leads to stationary states with real energy, naturally inter- pretable as bound states. The broken PT -symmetric phase is also captured by this correlation, with complex-conjugate pair of energies, interpreted as resonances.

  13. Thermal diffusion in Ni/Al multilayer

    SciTech Connect (OSTI)

    Swain, M.; Bhattacharya, D.; Singh, S.; Basu, S. [Solid State Physics Division, Bhabha Atomic Research Center, Mumbai 400085 (India); Gupta, M. [UGC-DAE-Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452017 (India)

    2013-02-05T23:59:59.000Z

    Two Ni/Al multilayers deposited by ion beam sputtering of nominal design [Ni(200A)/Al(100A)] Multiplication-Sign 5 and [Ni(50A)/Al(227A)] Multiplication-Sign 5 on Si substrates were annealed at 200 Degree-Sign C. As-deposited and annealed samples were characterized by x-ray diffraction (XRD) and x-ray reflectometry (XRR). The effort was to study the path of alloying in the above two multilayers of same elements but of opposite stoichiometric ratio. We find distinct differences in alloying of these samples.

  14. Palladium Nanoparticles by Electrospinning from Poly(acrylonitrile-co-acrylic acid)-PdCl2 Solutions. Relations between

    E-Print Network [OSTI]

    Yanikoglu, Berrin

    Palladium Nanoparticles by Electrospinning from Poly(acrylonitrile-co-acrylic acid)-PdCl2 Solutions mainly depends on the amount of acrylic acid functional groups and PdCl2 concentration in the spinning solution. Increasing acrylic acid concentration on polymer chains leads to larger Pd nanoparticles

  15. Microscopic return point memory in Co/Pd multilayer films

    SciTech Connect (OSTI)

    Seu, K.A.; Su, R.; Roy, S.; Parks, D.; Shipton, E.; Fullerton, E.E.; Kevan, S.D.

    2009-10-01T23:59:59.000Z

    We report soft x-ray speckle metrology measurements of microscopic return point and complementary point memory in Co/Pd magnetic films having perpendicular anisotropy. We observe that the domains assemble into a common labyrinth phase with a period that varies by nearly a factor of two between initial reversal and fields near saturation. Unlike previous studies of similar systems, the ability of the film to reproduce its domain structure after magnetic cycling through saturation varies from loop to loop, from position to position on the sample, and with the part of the speckle pattern used in the metrology measurements. We report the distribution of memory as a function of field and discuss these results in terms of the reversal process.

  16. Co-Pt core-shell nanostructured catalyst prepared by selective chemical vapor pulse deposition of Pt on Co as a cathode in polymer electrolyte fuel cells

    SciTech Connect (OSTI)

    Seo, Sang-Joon; Chung, Ho-Kyoon [SKKU Advanced Institute of Nanotechnology (SAINT) and Center for Human Interface Nanotechnology (HINT), Sungkyunkwan University, Suwon, Gyeonggi 440-746 (Korea, Republic of); Yoo, Ji-Beom [SKKU Advanced Institute of Nanotechnology (SAINT) and Center for Human Interface Nanotechnology (HINT), Sungkyunkwan University, Suwon, Gyeonggi 440-746, Korea and School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi 440-746 (Korea, Republic of); Chae, Heeyeop; Seo, Seung-Woo; Min Cho, Sung, E-mail: sungmcho@skku.edu [School of Chemical Engineering, Sungkyunkwan University, Suwon, Gyeonggi 440-746 (Korea, Republic of)

    2014-01-15T23:59:59.000Z

    A new type of PtCo/C catalyst for use as a cathode in polymer electrolyte fuel cells was prepared by selective chemical vapor pulse deposition (CVPD) of Pt on the surface of Co. The activity of the prepared catalyst for oxygen reduction was higher than that of a catalyst prepared by sequential impregnation (IMP) with the two metallic components. This catalytic activity difference occurs because the former catalyst has smaller Pt crystallites that produce stronger Pt-Co interactions and have a larger Pt surface area. Consequently, the CVPD catalyst has a great number of Co particles that are in close contact with the added Pt. The Pt surface was also electronically modified by interactions with Co, which were stronger in the CVPD catalyst than in the IMP catalyst, as indicated by X-ray diffraction, X-ray photoemission spectroscopy, and cyclic voltammetry measurements of the catalysts.

  17. Random matrix ensembles for $PT$-symmetric systems

    E-Print Network [OSTI]

    Eva-Maria Graefe; Steve Mudute-Ndumbe; Matthew Taylor

    2015-05-28T23:59:59.000Z

    Recently much effort has been made towards the introduction of non-Hermitian random matrix models respecting PT-symmetry. Here we show that there is a one-to-one correspondence between complex $PT$-symmetric matrices and split-complex and split-quaternionic versions of Hermitian matrices. We introduce two new random matrix ensembles of (a) Gaussian split-complex Hermitian, and (b) Gaussian split-quaternionic Hermitian matrices, of arbitrary sizes. They are related to the split signature versions of the complex and the quaternionic numbers, respectively. We conjecture that these ensembles represent universality classes for PT-symmetric matrices. For the case of $2\\times2$ matrices we derive analytic expressions for the joint probability distributions of the eigenvalues, the one-level densities and the level spacings in the case of real eigenvalues.

  18. Scattering in a varying mass PT symmetric double heterojunction

    E-Print Network [OSTI]

    Anjana Sinha; R. Roychoudhury

    2013-06-10T23:59:59.000Z

    We observe that the reflection and transmission coefficients of a particle within a double, PT symmetric heterojunction with spatially varying mass, show interesting features, depending on the degree of non Hermiticity, although there is no spontaneous breakdown of PT symmetry. The potential profile in the intermediate layer is considered such that it has a non vanishing imaginary part near the heterojunctions. Exact analytical solutions for the wave function are obtained, and the reflection and transmission coefficients are plotted as a function of energy, for both left as well as right incidence. As expected, the spatial dependence on mass changes the nature of the scattering solutions within the heterojunctions, and the space-time (PT) symmetry is responsible for the left-right asymmetry in the reflection and transmission coefficients. However, the non vanishing imaginary component of the potential near the heterojunctions gives new and interesting results.

  19. Equiatomic CoPt thin films with extremely high coercivity

    SciTech Connect (OSTI)

    Varghese, Binni; Piramanayagam, S. N., E-mail: Prem-SN@dsi.a-star.edu.sg; Yang, Yi; Kai Wong, Seng; Khume Tan, Hang; Kiat Lee, Wee [Data Storage Institute, (A-STAR) Agency for Science, Technology and Research, DSI Building, 5, Engineering Drive 1, Singapore 117608 (Singapore); Okamoto, Iwao [Western Digital Corporation, Singapore 638552 (Singapore)

    2014-05-07T23:59:59.000Z

    In this paper, magnetic and structural properties of near-equiatomic CoPt thin films, which exhibited a high coercivity in the film-normal direction—suitable for perpendicular magnetic recording media applications—are reported. The films exhibited a larger coercivity of about 6.5 kOe at 8?nm. The coercivity showed a monotonous decrease as the film thickness was increased. The transmission electron microscopy images indicated that the as fabricated CoPt film generally consists of a stack of magnetically hard hexagonal-close-packed phase, followed by stacking faults and face-centred-cubic phase. The thickness dependent magnetic properties are explained on the basis of exchange-coupled composite media. Epitaxial growth on Ru layers is a possible factor leading to the unusual observation of magnetically hard hcp-phase at high concentrations of Pt.

  20. Metastable phase diagram for Ni-implanted Al and pulse surface melted Al(Ni)

    SciTech Connect (OSTI)

    Follstaedt, D.M.; Picraux, S.T.

    1984-01-01T23:59:59.000Z

    The microstructure of <110> Al implanted with Ni was examined before and after subsequent electron beam pulsed surface melting (65 ns, 1.7 J/cm/sup 2/). Both processes were done with the Al substrate at room temperature. Implantation at several energies (160 to 15 keV) into a given sample produced a nearly constant measured Ni concentration through a approx. 0.1 ..mu..m region below the surface (7). Such samples with concentrations from 8 to 25 at. % Ni were examined, along with a sample with a peak concentration of 32 at. % Ni.

  1. Layering and temperature-dependent magnetization and anisotropy of naturally produced Ni/NiO multilayers

    SciTech Connect (OSTI)

    Pappas, S. D.; Trachylis, D.; Velgakis, M. J. [Laboratory of High-Tech Materials, School of Engineering, University of Patras, 26504 Patras (Greece); Kapaklis, V.; Joensson, P. E.; Papaioannou, E. Th. [Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala (Sweden); Delimitis, A. [Chemical Process Engineering Research Institute (CPERI), Centre for Research and Technology Hellas (CERTH), 57001 Thermi, Thessaloniki (Greece); Poulopoulos, P. [Laboratory of High-Tech Materials, School of Engineering, University of Patras, 26504 Patras (Greece); Institut fuer Experimentalphysik, Freie Universitaet Berlin, Arnimallee 14, D-14195 Berlin-Dahlem (Germany); Materials Science Department, University of Patras, 26504 Patras (Greece); Fumagalli, P. [Institut fuer Experimentalphysik, Freie Universitaet Berlin, Arnimallee 14, D-14195 Berlin-Dahlem (Germany); Politis, C. [Laboratory of High-Tech Materials, School of Engineering, University of Patras, 26504 Patras (Greece); Department of Materials Science and Engineering, University of Texas at Arlington, Arlington, Texas 76019 (United States)

    2012-09-01T23:59:59.000Z

    Ni/NiO multilayers were grown by magnetron sputtering at room temperature, with the aid of the natural oxidation procedure. That is, at the end of the deposition of each single Ni layer, air is let to flow into the vacuum chamber through a leak valve. Then, a very thin NiO layer ({approx}1.2 nm) is formed. Simulated x-ray reflectivity patterns reveal that layering is excellent for individual Ni-layer thickness larger than 2.5 nm, which is attributed to the intercalation of amorphous NiO between the polycrystalline Ni layers. The magnetization of the films, measured at temperatures 5-300 K, has almost bulk-like value, whereas the films exhibit a trend to perpendicular magnetic anisotropy (PMA) with an unusual significant positive interface anisotropy contribution, which presents a weak temperature dependence. The power-law behavior of the multilayers indicates a non-negligible contribution of higher order anisotropies in the uniaxial anisotropy. Bloch-law fittings for the temperature dependence of the magnetization in the spin-wave regime show that the magnetization in the multilayers decreases faster as a function of temperature than the one of bulk Ni. Finally, when the individual Ni-layer thickness decreases below 2 nm, the multilayer stacking vanishes, resulting in a dramatic decrease of the interface magnetic anisotropy and consequently in a decrease of the perpendicular magnetic anisotropy.

  2. Electroslag surfacing of steel shafting with Ni alloy 625 and 70Cu-30Ni strip

    SciTech Connect (OSTI)

    Devletian, J.H.; Gao, Y.P.; Wood, W.E. [Oregon Graduate Inst. of Science and Technology, Portland, OR (United States)

    1996-12-31T23:59:59.000Z

    A comprehensive study of electroslag surfacing (ESS) of steel with Ni Alloy 625 and 70Cu-30Ni strip electrodes was conducted to establish the feasibility of replacing forged bearing sleeves on propulsion shafting with integral weld surfacing. The base material was MIL-S-23284, Class 1 steel in the form of 41--66 cm (16--26 in.) diameter shafting and 76 mm (3 in.) thick flat plate. All ESS was carried out at a heat input level of approximately 5.9kJ/mm (150 kJ/in.) using 30 x 0.5 mm (1.2 x 0.02 in.) strip electrodes. Assessments of mechanical properties and microstructure of Ni Alloy 625 surfacing and 70Cu-30Ni surfacing were conducted to establish the structure-property relationships in these complex alloy systems. In addition, a solidification cracking test was developed to determine the relative cracking susceptibilities of these strip surfacing alloys. Although the Ni Alloy 625 surfacing contained small islands of interdendritic MC type carbides and Laves phase, the mechanical properties of this surfacing were satisfactory. The 70Cu-30Ni surfacing required a buttering layer of 30Cu-70Ni or pure Ni to prevent solidification cracking. The inherent ductility-dip sensitivity of 70Cu-30Ni surfacing was overcome by the development of a suitable ESS procedure.

  3. Giant Quadrupole-Resonance in Ni Isotopes

    E-Print Network [OSTI]

    Youngblood, David H.; Lui, YW; Garg, U.; Peterson, R. J.

    1992-01-01T23:59:59.000Z

    PHYSICAL REVIEW C VOLUME 45, NUMBER 5 MAY 1992 Giant quadrupole resonance in Ni isotopes D. H. Youngblood and Y.-%. Lui Texas A&M UniUersity, College Station, Texas 77843 U. Garg University of Notre Dame, South Bend, Indiana 46556 R. J...R )' 0.53 0.68 0.69 0.78 E2 EWSR (%) 58+12 76+14 78+14 90+16 Cp 0.80+0.04 0.84+0.04 0.82+0. 12 1.05+0. 10 2174 YOUNGBLOOD, LUI, GARG, AND PETERSON 45 1000 100 60Ni(n, n') E = 129 MeV 1 000 100 58Ni(n, n') 10 10 100 z' 1000 64Ni...

  4. The effect of impregnation sequence on the hydrogenation activity and selectivity of supported Pt/Ni bimetallic catalysts

    E-Print Network [OSTI]

    Frenkel, Anatoly

    of acetylene in the presence of ethylene [22], and the selective hydrogenation of acrolein toward its

  5. Understanding the Nucleation and Growth of Metals on TiO2: Co Compared to Au, Ni, and Pt

    E-Print Network [OSTI]

    Henkelman, Graeme

    the steam reforming of ethanol,24 preferential oxidation of CO in hydrogen,25 and oxidative dehydrogenation

  6. PdAgAu alloy with high resistance to corrosion by H{sub 2}S

    SciTech Connect (OSTI)

    Braun, Fernando; Miller, James B.; Gellman, Andrew J.; Tarditi, Ana M.; Fleutot, Benoit; Petro, Kondratyuk, Cornaglia, Laura M

    2012-12-01T23:59:59.000Z

    PdAgAu alloy films were prepared on porous stainless steel supports by sequential electroless deposition. Two specific compositions, Pd{sub 83}Ag{sub 2}Au{sub 15} and Pd{sub 74}Ag{sub 14}Au{sub 12}, were studied for their sulfur tolerance. The alloys and a reference Pd foil were exposed to 1000 H{sub 2}S/H{sub 2} at 623 K for periods of 3 and 30 hours. The microstructure, morphology and bulk composition of both nonexposed and H{sub 2}S-exposed samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). XRD and SEM analysis revealed time-dependent growth of a bulk Pd{sub 4}S phase on the Pd foil during H{sub 2}S exposure. In contrast, the PdAgAu ternary alloys displayed the same FCC structure before and after H{sub 2}S exposure. In agreement with the XRD and SEM results, sulfur was not detected in the bulk of either ternary alloy samples by EDS, even after 30 hours of H{sub 2}S exposure. X-ray photoelectron spectroscopy (XPS) depth profiles were acquired for both PdAgAu alloys after 3 and 30 hours of exposure to characterize sulfur contamination near their surfaces. Very low S 2p and S 2s XPS signals were observed at the top-surfaces of the PdAgAu alloys, and those signals disappeared before the etch depth reached ~ 10 nm, even for samples exposed to H{sub 2}S for 30 hours. The depth profile analyses also revealed silver and gold segregation to the surface of the alloys; preferential location of Au on the alloys surface may be related to their resistance to bulk sulfide formation. In preliminary tests, a PdAgAu alloy membrane displayed higher initial H{sub 2} permeability than a similarly prepared pure Pd sample and, consistent with resistance to bulk sulfide formation, lower permeability loss in H{sub 2}S than pure Pd.

  7. Antiferromagnetic Kondo lattice in the layered compound CePd1–xBi? and comparison to the superconductor LaPd1–xBi?

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

    Han, Fei; Wan, Xiangang; Phelan, Daniel; Stoumpos, Constantinos C.; Sturza, Mihai; Malliakas, Christos D.; Li, Qing'an; Han, Tian-Heng; Zhao, Qingbiao; Chung, Duck Young; et al

    2015-07-01T23:59:59.000Z

    The layered compound CePd1–xBi? with the tetragonal ZrCuSi?-type structure was obtained from excess Bi flux. Magnetic susceptibility data of CePd1–xBi? show an antiferromagnetic ordering below 6 K and are anisotropic along the c axis and the ab plane. The anisotropy is attributed to crystal-electric-field (CEF) effects and a CEF model which is able to describe the susceptibility data is given. An enhanced Sommerfeld coefficient ? of 0.191 J mol Ce?¹ K?² obtained from specific-heat measurement suggests a moderate Kondo effect in CePd1–xBi?. Other than the antiferromagnetic peak at 6 K, the resistivity curve shows a shoulderlike behavior around 75 Kmore »which could be attributed to the interplay between Kondo and CEF effects. Magnetoresistance and Hall-effect measurements suggest that the interplay reconstructs the Fermi-surface topology of CePd1–xBi? around 75 K. Electronic structure calculations reveal that the Pd vacancies are important to the magnetic structure and enhance the CEF effects which quench the orbital moment of Ce at low temperatures.« less

  8. Switching of 800 nm femtosecond laser pulses using a compact PMN-PT modulator

    E-Print Network [OSTI]

    Adany, Peter; Price, E. Shane; Johnson, Carey K.; Zhang, Run; Hui, Rongqing

    2009-03-13T23:59:59.000Z

    A voltage-controlled birefringent cell based on ceramic PMN-PT material is used to enable fast intensity modulation of femtosecond laser pulses in the 800 nm wavelength window. The birefringent cell based on a PMN-PT ...

  9. Adsorption and diffusion of a single Pt atom on gamma-Al2O3 surfaces...

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

    diffusion of a single Pt atom on gamma-Al2O3 surfaces. Adsorption and diffusion of a single Pt atom on gamma-Al2O3 surfaces. Abstract: Motivated to better understand the...

  10. NOx Uptake Mechanism on Pt/BaO/Al2O3 Catalysts. | EMSL

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

    Al2O3 Catalysts. NOx Uptake Mechanism on PtBaOAl2O3 Catalysts. Abstract: The NOx adsorption mechanism on PtBaOAl2O3 catalysts was investigated by performing NOx storage...

  11. Damage Profiles and Ion Distribution in Pt-irradiated SiC. |...

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

    Damage Profiles and Ion Distribution in Pt-irradiated SiC. Damage Profiles and Ion Distribution in Pt-irradiated SiC. Abstract: Single crystalline 6H-SiC samples were irradiated at...

  12. Enhanced high temperature performance of MgAl2O4-supported Pt...

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

    high temperature performance of MgAl2O4-supported Pt-BaO lean NOx trap catalysts. Enhanced high temperature performance of MgAl2O4-supported Pt-BaO lean NOx trap catalysts....

  13. Electronic circuits having NiAl and Ni.sub.3 Al substrates

    DOE Patents [OSTI]

    Deevi, Seetharama C. (Midlothian, VA); Sikka, Vinod K. (Oak Ridge, TN)

    1999-01-01T23:59:59.000Z

    An electronic circuit component having improved mechanical properties and thermal conductivity comprises NiAl and/or Ni.sub.3 Al, upon which an alumina layer is formed prior to applying the conductive elements. Additional layers of copper-aluminum alloy or copper further improve mechanical strength and thermal conductivity.

  14. nucl-ex/970400924Apr1997 Charged pions from Ni on Ni collisions

    E-Print Network [OSTI]

    Boyer, Edmond

    , Poland 11 Rudjer Boskovic Institute, Zagreb, Croatia 1 #12;Abstract Charged pions from Ni + Ni reactions number of participants increase with beam energy, in accordance with earlier studies of the Ar + KCl and La + La systems. The pion kinetic energy spectra have concave shape and are fitted

  15. Ligand exchange in gold-coated FePt nanoparticles

    E-Print Network [OSTI]

    de la Presa, P; Morales, M P; Hernando, A; 10.1109/TMAG.2008.2002251

    2009-01-01T23:59:59.000Z

    In this work we present the magnetic properties of gold coated FePt nanoparticles and the study of stable aqueous dispersions of FePt@Au and FePt synthesized after ligand exchange with mercaptoundecanoic acid. The particle size determined from TEM micrographs goes from 4 nm for the uncoated nanoparticles to a maximum of 10 nm for the gold coated ones indicating that the thickness of the shell ranges from 1 to 3 nm. The magnetic characterization consists in hysteresis cycles at 10 and 300 K. The results show that, at low field and room temperature, the magnetic behavior of uncoated and coated nanoparticles are surprisingly quite similar. Since the gold coated nanoparticles keep the magnetic properties of FePt and the presence of gold improves the functionalization of nanoparticles, the system is suitable for biological application. Mercaptoundecanoic ligand transfer was used to render water stable nanoparticles in a wide pH range. Transmission electron microscopy and dynamic light scattering results show the n...

  16. Rubrik 30/34 pt Berthold Akzidenz Bold

    E-Print Network [OSTI]

    Rubrik 30/34 pt Berthold Akzidenz Bold EPOK ­ Centre for Organic Food and Farming Research Agenda for Organic Agriculture 2013 Research challenges and knowledge requirements for organic food and farming Maria: SLU, EPOK ­ Centre for Organic Food and Farming Layout: Pelle Fredriksson, SLU, EPOK Photographs

  17. PT symmetry of a conditionally exactly solvable potential

    E-Print Network [OSTI]

    Anjana Sinha; Geza Levai; Pinaki Roy

    2004-01-12T23:59:59.000Z

    A conditionally exactly solvable potential, the supersymmetric partner of the harmonic oscillator is investigated in the PT-symmetric setting. It is shown that a number of properties characterizing shape-invariant and Natanzon-class potentials generated by an imaginary coordinate shift $x-{\\rm i}\\epsilon$ also hold for this potential outside the Natanzon class.

  18. Characteristics of Pt-K/MgAl2O4 lean NOx trap catalysts. | EMSL

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

    Pt-KMgAl2O4 lean NOx trap catalysts. Characteristics of Pt-KMgAl2O4 lean NOx trap catalysts. Abstract: We report the various characteristics of Pt-KMgAl2O4 lean NOx trap (LNT)...

  19. Reduction of Sintering during Annealing of FePt Nanoparticles Coated with Iron Oxide

    E-Print Network [OSTI]

    Laughlin, David E.

    Reduction of Sintering during Annealing of FePt Nanoparticles Coated with Iron Oxide Chao Liu °C for 30 min at which 2.6-nm FePt nanoparticles without oxide shell coating start to sinter. LowVised Manuscript ReceiVed October 12, 2004 FePt/iron oxide core/shell nanoparticles are synthesized by a two step

  20. Carbon supported PtRh catalysts for ethanol oxidation in alkaline direct ethanol fuel cell

    E-Print Network [OSTI]

    Zhao, Tianshou

    Carbon supported PtRh catalysts for ethanol oxidation in alkaline direct ethanol fuel cell S and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China a r t i c l e i n f o Article history: Received 26 carbon supported PtRh catalysts and compare their catalytic activities with that of Pt/C in alkaline

  1. Ni Sorption on Pyrophyllite: Evidence for the Formation of Ni-Al Hydroxide and Its Transformation into Ni-Silicate by Visible,

    E-Print Network [OSTI]

    Sparks, Donald L.

    into Ni-Silicate by Visible, Infrared and XANES Spectroscopy and Thermogravimetry A. C. Scheinost, R. G suggest either the formation of layered double hydroxides or of layer silicates. Desorption studies polymerization of SiO causes the formation of 1:1 or 2:1 Ni silicates, where the original Ni-Al hydroxide

  2. The effect of PdZn particle size on reverse-water-gas-shift reaction...

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

    RWGS activity is consistent with that previously observed for the steam reforming of methanol, i.e., higher CO selectivity on smaller PdZn particles. Thus, RWGS has been...

  3. Method and Pd/V2 O5 device for H2 detection

    DOE Patents [OSTI]

    Liu, Ping (San Diego, CA); Tracy, C. Edwin (Golden, CO); Pitts, J. Roland (Lakewood, CO); Smith, II, R. Davis (Golden, CO); Lee, Se-Hee (Lakewood, CO)

    2011-12-27T23:59:59.000Z

    Methods and Pd/V.sub.2O.sub.5 devices for hydrogen detection are disclosed. An exemplary method of preparing an improved sensor for chemochromic detection of hydrogen gas over a wide response range exhibits stability during repeated coloring/bleaching cycles upon exposure and removal of hydrogen gas. The method may include providing a substrate. The method may also include depositing a V.sub.20.sub.5 layer that functions as a H.sub.2 insertion host in a Pd/V.sub.20.sub.5 hydrogen sensor to be formed on said substrate. The method may also include depositing a Pd layer onto said V.sub.20.sub.5 layer; said Pd layer functioning as an optical modulator.

  4. Process design and modeling for the production of triacylglycerols (TAGs) in Rhodococcus opacus PD630

    E-Print Network [OSTI]

    Miller, Neidi

    2012-01-01T23:59:59.000Z

    The oleaginous microorganism Rhodococcus opacus PD630 was used to study the characteristics and kinetics of the accumulation of triacylglycerols (TAGs) in cells. In this process, accumulation of TAG is stimulated when a ...

  5. Comparative and Functional Genomics of Rhodococcus opacus PD630 for Biofuels Development

    E-Print Network [OSTI]

    Ghiviriga, Ion

    The Actinomycetales bacteria Rhodococcus opacus PD630 and Rhodococcus jostii RHA1 bioconvert a diverse range of organic substrates through lipid biosynthesis into large quantities of energy-rich triacylglycerols (TAGs). ...

  6. Digital Deposition of Ultrathin Pd Films on Well-Defined Pt(111) Electrodes via Surface-Limited Redox Replacement Reaction: An Electron Spectroscopy-Electrochemistry Study

    E-Print Network [OSTI]

    Hossain, Mohammad

    2010-12-04T23:59:59.000Z

    to Kyle for his assistance in conducting the experiments. I am thankful to Raj Karr, Miguel Cruz-Quiñons, Laura Granda Marulanda, James Cantu, Stephen Fordham, and Joshua Fonzy who aided in this project in many ways. I would like to thank the support...

  7. Recycling of used Ni-MH rechargeable batteries

    SciTech Connect (OSTI)

    Yoshida, T.; Ono, H.; Shirai, R. [Mitsui Mining and Smelting Co., Ltd., Ageo, Saitama (Japan). Corporate R and D Center

    1995-12-31T23:59:59.000Z

    The Ni-MH (nickel metal hydride) rechargeable battery was developed several years ago. Its higher electrochemical capacity and greater safety compared with the Ni-Cd rechargeable battery have resulted in very rapid increase in its production. The Ni-MH rechargeable battery consists of Ni, Co and rare earth metals, so that recycling is important to recover these valuable mineral resources. In this study, a basic recycling process for used Ni-MH rechargeable batteries has been developed, in which the Ni, Co and rare earth elements are recovered through a combination of mechanical processing and hydrometallurgical processing.

  8. Nickel recovery from electronic waste II Electrodeposition of Ni and Ni–Fe alloys from diluted sulfate solutions

    SciTech Connect (OSTI)

    Robotin, B. [Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos Street, RO-400028 Cluj-Napoca (Romania); Ispas, A. [Fachgebiet Elektrochemie und Galvanotechnik II, Technische Universität Ilmenau, D-98693 Ilmenau (Germany); Coman, V. [Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos Street, RO-400028 Cluj-Napoca (Romania); Bund, A. [Fachgebiet Elektrochemie und Galvanotechnik II, Technische Universität Ilmenau, D-98693 Ilmenau (Germany); Ilea, P., E-mail: pilea@chem.ubbcluj.ro [Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos Street, RO-400028 Cluj-Napoca (Romania)

    2013-11-15T23:59:59.000Z

    Highlights: • Ni can be recovered from EG wastes as pure Ni or as Ni–Fe alloys. • The control of the experimental conditions gives a certain alloy composition. • Unusual deposits morphology shows different nucleation mechanisms for Ni vs Fe. • The nucleation mechanism was progressive for Ni and instantaneous for Fe and Ni–Fe. - Abstract: This study focuses on the electrodeposition of Ni and Ni–Fe alloys from synthetic solutions similar to those obtained by the dissolution of electron gun (an electrical component of cathode ray tubes) waste. The influence of various parameters (pH, electrolyte composition, Ni{sup 2+}/Fe{sup 2+} ratio, current density) on the electrodeposition process was investigated. Scanning electron microscopy (SEM) and X-ray fluorescence analysis (XRFA) were used to provide information about the obtained deposits’ thickness, morphology, and elemental composition. By controlling the experimental parameters, the composition of the Ni–Fe alloys can be tailored towards specific applications. Complementarily, the differences in the nucleation mechanisms for Ni, Fe and Ni–Fe deposition from sulfate solutions have been evaluated and discussed using cyclic voltammetry and potential step chronoamperometry. The obtained results suggest a progressive nucleation mechanism for Ni, while for Fe and Ni–Fe, the obtained data points are best fitted to an instantaneous nucleation model.

  9. Exchange bias beyond the superparamagnetic blocking temperature of the antiferromagnet in a Ni-NiO nanoparticulate system

    SciTech Connect (OSTI)

    Roy, Aparna, E-mail: aparna.roy@ua.pt, E-mail: aparnaroy15@gmail.com; Ferreira, J. M. F. [Department of Materials and Ceramics Engineering and CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); De Toro, J. A.; Muniz, P.; Riveiro, J. M. [Departamento de Fisica Aplicada, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Amaral, V. S. [Department of Physics and CICECO, University of Aveiro, 3810-193 Aveiro (Portugal)

    2014-02-21T23:59:59.000Z

    We report magnetic and exchange bias studies on Ni-NiO nanoparticulate systems synthesized by a two-step process, namely, chemical reduction of a Ni salt followed by air annealing of the dried precipitate in the temperature range 400–550?°C. Size of Ni and NiO crystallites as estimated from X–ray diffraction line broadening ranges between 10.5–13.5?nm and 2.3–4?nm, respectively. The magneto-thermal plots (M-T) of these bi-magnetic samples show a well developed peak in the vicinity of 130?K. This has been identified as the superparamagnetic blocking temperature “T{sub B}” of NiO. Interestingly, all samples exhibit exchange bias even above their respective NiO blocking temperatures, right up to 300?K, the maximum temperature of measurement. This is in contrast to previous reports since exchange bias requires the antiferromagnetic NiO to have a stable direction of its moment in order to pin the ferromagnet (Ni) magnetization, whereas such stability is unlikely above T{sub B} since the NiO is superparamagnetic, its moment flipping under thermal activation. Our observation is elucidated by taking into account the core-shell morphology of the Ni-NiO nanoparticles whereby clustering of some of these nanoparticles connects their NiO shells to form extended continuous regions of NiO, which because of their large size remain blocked at T?>?T{sub B}, with thermally stable spins capable of pinning the Ni cores and giving rise to exchange bias. The investigated samples may thus be envisaged as being constituted of both isolated core-shell Ni-NiO nanoparticles as well as clustered ones, with T{sub B} denoting the blocking temperature of the NiO shell of the isolated particles.

  10. Influence of surface segregation on magnetic properties of FePt nanoparticles

    SciTech Connect (OSTI)

    Lv, Hongyan [Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261 (United States) [Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261 (United States); Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Lei, Yinkai; Datta, Aditi; Wang, Guofeng [Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261 (United States)] [Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261 (United States)

    2013-09-23T23:59:59.000Z

    Surface segregation leads to chemical disordering in magnetic alloy nanostructures and thus could have profound impact upon the magnetic properties of these nanostructures. In this study, we used the first-principles density functional theory calculation method to determine how Pt surface segregation (exchanging interior Pt with surface Fe atoms) would affect the magnetic properties of L1{sub 0} ordered FePt nanoparticles. For both cuboid and cuboctahedral FePt nanoparticles, we predicted that the Pt surface segregation process could cause a decrease in total magnetic moments, a change in (easy and/or hard) magnetization axes, and a reduction in magnetic anisotropy.

  11. Structure Analysis of a Precipitate Phase in an Ni-Rich High...

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

    Structure Analysis of a Precipitate Phase in an Ni-Rich High Temperature NiTiHf Shape Memory Alloy. Structure Analysis of a Precipitate Phase in an Ni-Rich High Temperature NiTiHf...

  12. Energy absorption in Ni-Mn-Ga/ polymer composites

    E-Print Network [OSTI]

    Feuchtwanger, Jorge

    2006-01-01T23:59:59.000Z

    In recent years Ni-Mn-Ga has attracted considerable attention as a new kind of actuator material. Off-stoichiometric single crystals of Ni2MnGa can regularly exhibit 6% strain in tetragonal martensites and orthorhombic ...

  13. Carbon Nanotube Growth Using Ni Catalyst in Different Layouts

    E-Print Network [OSTI]

    Nguyen, H. Q.

    Vertically aligned carbon nanotubes have been grown using Ni as catalyst by plasma enhanced chemical vapor deposition system (PECVD) in various pre-patterned substrates. Ni was thermally evaporated on silicon substrates ...

  14. ag fe ni: Topics by E-print Network

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

    conduction-band states of NiO 100 thin films grown onto Ag 100 have charac- terized NiO monocrystalline thin films has shown up both onto insulating i.e., MgO, Ref. 21 Marcon,...

  15. Fabrication and temperature-dependent magnetic properties of one-dimensional multilayer Au–Ni–Au–Ni–Au nanowires

    SciTech Connect (OSTI)

    Ishrat, S. [School of Electronic and Electrical Engineering and Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Maaz, K. [School of Electronic and Electrical Engineering and Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Nanomaterials Research Group, Physics Division, PINSTECH, Nilore, Islamabad (Pakistan); Lee, Kyu-Joon [Department of Physics, Sogang University, Seoul 121-742 (Korea, Republic of); Jung, Myung-Hwa, E-mail: mhjung@sogang.ac.kr [Department of Physics, Sogang University, Seoul 121-742 (Korea, Republic of); Kim, Gil-Ho, E-mail: ghkim@skku.edu [School of Electronic and Electrical Engineering and Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2014-02-15T23:59:59.000Z

    Multilayer Au–Ni–Au–Ni–Au nanowires with a controlled diameter of ?100 nm were synthesized by electrochemical deposition in porous alumina templates. The length of each Ni-segment was controlled up to ?230 nm, while the length of the Au segment sandwiched between two Ni segments was ?180 nm. X-ray diffraction patterns and energy-dispersive X-ray spectra confirmed the formation of purely crystalline nanowires. The magnetic properties of the multilayer Au–Ni–Au–Ni–Au nanowires were investigated in the temperature range 2–300 K. Room-temperature magnetic hysteresis confirmed the ferromagnetic nature of the nanowires. The plot of coercivity as a function of temperature (from 2 to 300 K) followed law applicable for ferromagnetic nanostructures. The magnetization tended to increase as the temperature decreased, following the modified Bloch's law similar to ferromagnetic nanoparticles. - Graphical abstract: (a) SEM image of Au–Ni–Au–Ni–Au nanowire with 230 nm Ni segment length and 180 nm Au sandwiched between Ni segments (b) Kneller's law (c) Bloch's law Display Omitted - Highlights: • Electrochemical fabrication of Au–Ni–Au–Ni–Au nanowires in alumina templates. • Formation of beadlike structure of Ni segments. • Coercivity versus T follows Kneller's law for ferromagnetic materials. • Magnetization as a function of temperature follows the modified Bloch's law.

  16. Approved Module Information for AM30PD, 2014/5 Module Title/Name: Partial Differential Equations Module Code: AM30PD

    E-Print Network [OSTI]

    Neirotti, Juan Pablo

    Module Code: AM30PD School: Engineering and Applied Science Module Type: Standard Module New Module@aston.ac.uk Telephone Number Not Specified Office Not Specified Additional Module Tutor(s): W Cox. Level Description: Lectures/Tutorials Module Assessment Methods of Assessment & associated weighting (including approaches

  17. Consistent Data Assimilation of Isotopes: 242Pu and 105Pd

    SciTech Connect (OSTI)

    G. Palmiotti; H. Hiruta; M. Salvatores

    2012-09-01T23:59:59.000Z

    In this annual report we illustrate the methodology of the consistent data assimilation that allows to use the information coming from integral experiments for improving the basic nuclear parameters used in cross section evaluation. A series of integral experiments are analyzed using the EMPIRE evaluated files for 242Pu and 105Pd. In particular irradiation experiments (PROFIL-1 and -2, TRAPU-1, -2 and -3) provide information about capture cross sections, and a critical configuration, COSMO, where fission spectral indexes were measured, provides information about fission cross section. The observed discrepancies between calculated and experimental results are used in conjunction with the computed sensitivity coefficients and covariance matrix for nuclear parameters in a consistent data assimilation. The results obtained by the consistent data assimilation indicate that not so large modifications on some key identified nuclear parameters allow to obtain reasonable C/E. However, for some parameters such variations are outside the range of 1 s of their initial standard deviation. This can indicate a possible conflict between differential measurements (used to calculate the initial standard deviations) and the integral measurements used in the statistical data adjustment. Moreover, an inconsistency between the C/E of two sets of irradiation experiments (PROFIL and TRAPU) is observed for 242Pu. This is the end of this project funded by the Nuclear Physics Program of the DOE Office of Science. We can indicate that a proof of principle has been demonstrated for a few isotopes for this innovative methodology. However, we are still far from having explored all the possibilities and made this methodology to be considered proved and robust. In particular many issues are worth further investigation: • Non-linear effects • Flexibility of nuclear parameters in describing cross sections • Multi-isotope consistent assimilation • Consistency between differential and integral experiments

  18. Effects of Ag underlayers on the microstructure and magnetic properties of epitaxial FePt thin films

    E-Print Network [OSTI]

    Laughlin, David E.

    in the in situ ordering of the FePt thin film at reduced temperatures. The microstructural and magneticPt thin films have drawn considerable attention as a potential high-density magnetic recording material.1. Because the 111 plane is the FePt close-packed plane, the FePt thin film deposited directly onto

  19. High Temperature coatings based on {beta}-NiAI

    SciTech Connect (OSTI)

    Severs, Kevin

    2012-07-10T23:59:59.000Z

    High temperature alloys are reviewed, focusing on current superalloys and their coatings. The synthesis, characerization, and oxidation performance of a NiAl–TiB{sub 2} composite are explained. A novel coating process for Mo–Ni–Al alloys for improved oxidation performance is examined. The cyclic oxidation performance of coated and uncoated Mo–Ni–Al alloys is discussed.

  20. Three-Dimensional EBSD Analysis of YSZ, NiO-YSZ and Ni-Alloy

    SciTech Connect (OSTI)

    Saraf, Laxmikant V.

    2012-01-03T23:59:59.000Z

    In this report, a method is discussed to perform successive milling on yttria-stabilized zirconia (YSZ), NiO-YSZ and Ni-alloy at the intervals of 85 nm 50 nm and 100 nm, respectively using a focused ion beam (FIB) followed by electron backscatter diffraction (EBSD) analysis on each slice. The EBSD data is then reconstructed to generate 3D volume. The 3D-EBSD band quality data is superimposed on inverse pole figure (IPF) grain orientation analysis to get a correlation with quality of band indexing. For the NiO-YSZ case, grain orientations and band quality factors were matched for grains {approx}250 nm diameters producing a high resolution 3D-EBSD data. For this case, a pore space in 3D volume was visible due to nanocrystalline NiO-YSZ grain network. The advantages of 3D EBSD are discussed in the context of its applications to SOFC research community.

  1. Magnetic Properties of Monodisperse NiHx Nanoparticles and Comparison to Those of Monodisperse Ni Nanoparticles

    E-Print Network [OSTI]

    Kim, Bongsoo

    for hydrogen storage for both fuel cells and electrodes in batteries.3-7 As a solid, NiHx has an advantage over Yongmin Chang Department of Diagnostic Radiology, School of Medicine, Kyungpook National Uni

  2. Electronic structure mechanism of spin-polarized electron transport in a NiC60Ni system

    E-Print Network [OSTI]

    Pandey, Ravi

    Laboratory, Weapons and Materials Research Directorate, ATTN: AMSRD-ARL-WM, Aberdeen Proving Ground, MD 21005 Abstract The nature of chemical bonding and its effect on spin-polarized electron transport in Ni­C60­Ni couple with metallic electrodes (e. g. Ni and Au), a key requirement for the Kondo effect

  3. Novel Pt/Mg(In)(Al)O catalysts for ethane and propane dehydrogenation

    SciTech Connect (OSTI)

    Sun, Pingping; Siddiqi, Georges; Vining, William C.; Chi, Miaofang; Bell, Alexis T. (UCB); (ORNL)

    2011-10-28T23:59:59.000Z

    Catalysts for the dehydrogenation of light alkanes were prepared by dispersing Pt on the surface of a calcined hydrotalcite-like support containing indium, Mg(In)(Al)O. Upon reduction in H{sub 2} at temperatures above 673 K, bimetallic particles of PtIn are observed by TEM, which have an average diameter of 1 nm. Analysis of Pt LIII-edge extended X-ray absorption fine structure (EXAFS) data shows that the In content of the bimetallic particles increases with increasing bulk In/Pt ratio and reduction temperature. Pt LIII-edge X-ray absorption near edge structure (XANES) indicates that an increasing donation of electronic charge from In to Pt occurs with increasing In content in the PtIn particles. The activity and selectivity of the Pt/Mg(In)(Al)O catalysts for ethane and propane dehydrogenation reactions are strongly dependent on the bulk In/Pt ratio. For both reactants, maximum activity was achieved for a bulk In/Pt ratio of 0.48, and at this In/Pt ratio, the selectivity to alkene was nearly 100%. Coke deposition was observed after catalyst use for either ethane or propane dehydrogenation, and it was observed that the alloying of Pt with In greatly reduced the amount of coke deposited. Characterization of the deposit by Raman spectroscopy indicates that the coke is present as highly disordered graphite particles <30 nm in diameter. While the amount of coke deposited during ethane and propane dehydrogenation are comparable, the effects on activity are dependent on reactant composition. Coke deposition had no effect on ethane dehydrogenation activity, but caused a loss in propane dehydrogenation activity. This difference is attributed to the greater ease with which coke produced on the surface of PtIn nanoparticles migrates to the support during ethane dehydrogenation versus propane dehydrogenation.

  4. Influence of Ni on Martensitic Phase Transformations in NiTi Shape Memory Alloys

    SciTech Connect (OSTI)

    Frenzel, J. [Ruhr University, Bochum, Germany; George, Easo P [ORNL; Dlouhy, A. [Institute of Physics of Materials, Brno, Czech Republic; Somsen, Ch. [Ruhr University, Bochum, Germany; Wagner, M. F.-X [Ruhr University, Bochum, Germany; Eggeler, G. [Ruhr University, Bochum, Germany

    2010-01-01T23:59:59.000Z

    High-precision data on phase transformation temperatures in NiTi, including numerical expressions for the effect of Ni on M{sub S}, M{sub F}, A{sub S}, A{sub F} and T{sub 0}, are obtained, and the reasons for the large experimental scatter observed in previous studies are discussed. Clear experimental evidence is provided confirming the predictions of Tang et al. 1999 regarding deviations from a linear relation between the thermodynamic equilibrium temperature and Ni concentration. In addition to affecting the phase transition temperatures, increasing Ni contents are found to decrease the width of thermal hysteresis and the heat of transformation. These findings are rationalized on the basis of the crystallographic data of Prokoshkin et al. 2004 and the theory of Ball and James. The results show that it is important to document carefully the details of the arc-melting procedure used to make shape memory alloys and that, if the effects of processing are properly accounted for, precise values for the Ni concentration of the NiTi matrix can be obtained.

  5. Deposition and characterization of TiZrV-Pd thin films by dc magnetron sputtering

    E-Print Network [OSTI]

    Wang, Jie; Xu, Yan-Hui; Wei, Wei; Fan, Le; Pei, Xiang-Tao; Hong, Yuan-Zhi; Wang, Yong

    2015-01-01T23:59:59.000Z

    TiZrV film is mainly applied in the ultra-high vacuum pipe of storage ring. Thin film coatings of palladium which was added onto the TiZrV film to increase the service life of nonevaporable getters and enhance pumping speed for H2, was deposited on the inner face of stainless steel pipes by dc magnetron sputtering using argon gas as the sputtering gas. The TiZrV-Pd film properties were investigated by atomic force microscope (AFM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and X-Ray Diffraction (XRD). The grain size of TiZrV and Pd film were about 0.42~1.3 nm and 8.5~18.25 nm respectively. It was found that the roughness of TiZrV films was small, about 2~4 nm, for Pd film it is large, about 17~19 nm. PP At. % of Pd in TiZrV/Pd films varied from 86.84 to 87.56 according to the XPS test results.

  6. Pd menbrane having improved H.sub.2-permeance, and method of making

    DOE Patents [OSTI]

    Vanderspurt, Thomas Henry (Glastonbury, CT); She, Ying (Worcester, MA); Dardas, Zissis (Worcester, MA); Walker, Craig (South Glastonbury, CT); MacLeod, James D. (Vernon, CT)

    2011-12-06T23:59:59.000Z

    An H.sub.2-permeable membrane system (117) comprises an electroless-deposited plating (115) of Pd or Pd alloy on a porous support (110, 110'). The Pd plating comprises face-centered cubic crystals cumulatively having a morphology of hexagonal platelets. The permeability to H.sub.2 of the membrane plating (115) on the porous support is significantly enhanced, being at least greater than about 1.3.times.10.sup.-8 molm.sup.-1s.sup.-Pa.sup.-0.5 at 350.degree. C., and even greater than about 3.4.times.10.sup.-8 molm.sup.-1s.sup.-1Pa.sup.-0.5. The porous support (110, 110') may be stainless steel (1100 and include a thin ceramic interlayer (110') on which the Pd is plated. The method of providing the electroless-deposited plating includes preheating a Pd electroless plating solution to near a plating temperature substantially greater than room temperature, e.g. 60.degree. C., prior to plating.

  7. Properties of electroless Ni-W-P amorphous alloys

    SciTech Connect (OSTI)

    Zhang Bangwei [Academia Sinica, Shenyang (China). International Centre of Materials Physics] [Academia Sinica, Shenyang (China). International Centre of Materials Physics; [Hunan Univ., Changsha (China). Dept. of Applied Physics; Hu Wangyu; Zhang Qinglong; Qu Xuanyuan [Hunan Univ., Changsha (China). Dept. of Applied Physics] [Hunan Univ., Changsha (China). Dept. of Applied Physics

    1996-08-01T23:59:59.000Z

    This paper describes work performed to determine some of the properties of the electroless Ni-W-P amorphous deposits. Phosphorus contents were varied up to 32 at.%, and the amorphous structure was found to be present at phosphorus contents above 5 at.%. Irrespective of P content, all the deposits exhibits excellent adhesion to metallic substrates. The addition of even small amounts of W provided greatly increased hardness compared with the plain Ni-P deposits. The wettability properties of the Ni-W-P deposits were found to be comparable to those of Ni-P and N-B-P deposits but inferior to those of Ni-B deposits.

  8. Microstructure of electrodeposited Cu-Ni binary alloy films

    SciTech Connect (OSTI)

    Mizushima, Io; Chikazawa, Masatoshi; Watanabe, Tohru [Tokyo Metropolitan Univ. (Japan). Dept. of Industrial Chemistry

    1996-06-01T23:59:59.000Z

    The codeposition of Cu and Ni in the electrodeposition method without a complexing agent is difficult, since the standard electrode potentials of Cu and Ni differ by approximately 600 mV. In this study, the electrodeposited Cu-Ni alloy films with various compositions were obtained using glycine as the complexing agent. Consequently, composition of the deposited Cu-Ni alloy films can be controlled by bath composition and pH, and the crystallographic structure of all the deposited Cu-Ni alloy films consists of a single solid solution and is not influenced by pH.

  9. In Situ XAS of Ni-W Hydrocracking Catalysts

    SciTech Connect (OSTI)

    Yang, N. [Argonne National Laboratory, Argonne, IL 60439 (United States); Mickelson, G. E.; Greenlay, N.; Bare, Simon R. [UOP LLC, Des Plaines, IL 60016 (United States); Kelly, S. D. [EXAFS Analysis, Bolingbrook, IL 60440 (United States)

    2007-02-02T23:59:59.000Z

    Ni-W based catalysts are very attractive in hydrotreating of heavy oil due to their high hydrogenation activity. In the present research, two catalyst samples, prepared by different methods, that exhibit significant differences in activity were sulfided in situ, and the local structure of the Ni and W were studied using X-ray absorption spectroscopy (XAS). The Ni XANES spectra were analyzed using a linear component fitting, and the EXAFS spectra of the WS2 platelets in the sulfided catalysts were modeled. The Ni and W are fully sulfided in the higher activity sample, and there are both unsulfided Ni ({approx}25%) and W (<10%) in the lower activity sample.

  10. 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.

  11. Growth of FePt encapsulated carbon nanotubes by thermal chemical vapor deposition

    SciTech Connect (OSTI)

    Fujiwara, Yuji, E-mail: fujiwara@phen.mie-u.ac.jp; Kaneko, Tetsuya; Hori, Kenta; Takase, Sho; Sato, Hideki; Maeda, Kohji; Kobayashi, Tadashi [Graduate School of Engineering, Mie University, Kurima-machiya-cho 1577, Tsu 514-8507 (Japan); Kato, Takeshi; Iwata, Satoshi [Department of Quantum Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Jimbo, Mutsuko [Department of Electrical and Electronic Engineering, Daido University, Takiharu-cho 10-3, Minami-ku, Nagoya 457-8530 (Japan)

    2014-03-15T23:59:59.000Z

    FePt encapsulated carbon nanotubes (CNTs) were grown by thermal chemical vapor deposition using an Fe/Pt bilayer catalyst. The CNTs were grown according to the base growth model. Selected area electron diffraction results revealed that the encapsulated particles were A1-FePt, L1{sub 0}-FePt, and Fe{sub 3}PtC. The crystal structures of particles found at the root parts of CNTs were not able to be identified, however. The layered structure of catalytic films seemed to be responsible for the difference in Pt content between particles found at tip and root parts of CNTs. Approximately 60% of CNTs grown at 800?°C had particles at their tip parts, compared to only 30% when the growth temperature was 700?°C, indicating that higher process temperatures promote particle encapsulation in CNTs.

  12. An An exactly solvable PT symmetric potential from the Natanzon class

    E-Print Network [OSTI]

    G. Levai; A. Sinha; P. Roy

    2003-06-05T23:59:59.000Z

    The ${\\cal PT}$ symmetric version of the generalised Ginocchio potential, a member of the general exactly solvable Natanzon potential class is analysed and its properties are compared with those of ${\\cal PT}$ symmetric potentials from the more restricted shape-invariant class. It is found that the ${\\cal PT}$ symmetric generalised Ginocchio potential has a number of properties in common with the latter potentials: it can be generated by an imaginary coordinate shift $x\\to x+{\\rm i}\\epsilon$; its states are characterised by the quasi-parity quantum number; the spontaneous breakdown of ${\\cal PT}$ symmetry occurs at the same time for all the energy levels; and it has two supersymmetric partners which cease to be ${\\cal PT}$ symmetric when the ${\\cal PT}$ symmetry of the original potential is spontaneously broken.

  13. Electron yield XAFS study of evaporated Co/Pd multilayers with various thickness ratios of Co to Pd sublayers: Simulations of the Co K-edge XAFS and fourier transforms

    SciTech Connect (OSTI)

    Choi, M. [Catholic Univ. Medical Coll., Seoul (Korea, Republic of). Dept. of Physics; Joo, J.H. [Korea Inst. of Science and Technology, Seoul (Korea, Republic of). Materials Design Lab.; Kim, S.K.; Kang, J.S.; Lee, Y.P. [Research Inst. of Industrial Science Technology, Pohang (Korea, Republic of); Shin, S.C. [Korea Advanced Inst. of Science and Technology, Seoul (Korea, Republic of); Heald, S.M. [Brookhaven National Lab., Upton, NY (United States)

    1992-11-01T23:59:59.000Z

    Electron-yield XAFS measurements using the NSLS were made on e-beam evaporated Co/Pd multilayers with various sublayer thicknesses and different thickness ratios of Co to Pd sublayers. The Co K-edge and the Pd K-edge XAFS data were obtained for the Co/Pd multilayers with sublayer thicknesses of 3{Angstrom}/ 4{Angstrom}, 15{Angstrom}/4{Angstrom}, 3{Angstrom}/15{Angstrom}, 2.1{Angstrom}/13.5{Angstrom}, and 2.2{Angstrom}/4.5{Angstrom}. Fourier transforms of Co K XAFS for most samples show a splitting of major peak, and the magnitude ratio of these split peaks varies systematically with the thickness ratio of the Pd sublayer to the Co sublayer, whereas the Fourier transforms of the Pd K XAFS for the same samples do not show a splitting of peaks. As a preliminary analysis, the Co K XAFS and the split peaks in the Fourier transform for the Co/Pd(3{Angstrom}/4{Angstrom}) case were simulated by using the FEFF calculations, and the Co K XAFS and the major peak in the fourier transform for the Co/Pd(15{Angstrom}/4{Angstrom}) case were also simulated consistently.

  14. Electron yield XAFS study of evaporated Co/Pd multilayers with various thickness ratios of Co to Pd sublayers: Simulations of the Co K-edge XAFS and fourier transforms

    SciTech Connect (OSTI)

    Choi, M. (Catholic Univ. Medical Coll., Seoul (Korea, Republic of). Dept. of Physics); Joo, J.H. (Korea Inst. of Science and Technology, Seoul (Korea, Republic of). Materials Design Lab.); Kim, S.K.; Kang, J.S.; Lee, Y.P. (Research Inst. of Industrial Science Technology, Pohang (Korea, Republic of)); Shin, S.C. (Korea Advanced Inst. of Science and Technology, Seoul (Korea, Republic of)); Heald, S.M.

    1992-01-01T23:59:59.000Z

    Electron-yield XAFS measurements using the NSLS were made on e-beam evaporated Co/Pd multilayers with various sublayer thicknesses and different thickness ratios of Co to Pd sublayers. The Co K-edge and the Pd K-edge XAFS data were obtained for the Co/Pd multilayers with sublayer thicknesses of 3[Angstrom]/ 4[Angstrom], 15[Angstrom]/4[Angstrom], 3[Angstrom]/15[Angstrom], 2.1[Angstrom]/13.5[Angstrom], and 2.2[Angstrom]/4.5[Angstrom]. Fourier transforms of Co K XAFS for most samples show a splitting of major peak, and the magnitude ratio of these split peaks varies systematically with the thickness ratio of the Pd sublayer to the Co sublayer, whereas the Fourier transforms of the Pd K XAFS for the same samples do not show a splitting of peaks. As a preliminary analysis, the Co K XAFS and the split peaks in the Fourier transform for the Co/Pd(3[Angstrom]/4[Angstrom]) case were simulated by using the FEFF calculations, and the Co K XAFS and the major peak in the fourier transform for the Co/Pd(15[Angstrom]/4[Angstrom]) case were also simulated consistently.

  15. 2012NatureAmerica,Inc.Allrightsreserved. 52 | VOL.8 NO.1 | 2013 | nature protocols

    E-Print Network [OSTI]

    Wang, Zhong L.

    DuctIon Background SERS was first observed in the 1970s on an electrochemically roughened Ag electrode1­3, which be substantially increased to obtain total enhancement factors of up to 104­105 for Pt, Pd, Ru, Rh, Ni and Co (refs

  16. This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research

    E-Print Network [OSTI]

    Cao, Guozhong

    modified electrode such as Pt [7­9], Au [10,11], Ag [12], Cu [13,14], Ni [15,16], Pd [17], alloy [18NTs electrode. The good analytical performance, low cost and simple preparation method make this novel electrode material promising for the development of effective glucose nonenzymatic glucose sensor. © 2012

  17. Stripe-to-bubble transition of magnetic domains at the spin reorientation of (Fe/Ni)/Cu/Ni/Cu(001)

    SciTech Connect (OSTI)

    Wu, J.; Choi, J.; Won, C.; Wu, Y. Z.; Scholl, A.; Doran, A.; Hwang, Chanyong; Qiu, Z.

    2010-06-09T23:59:59.000Z

    Magnetic domain evolution at the spin reorientation transition (SRT) of (Fe/Ni)/Cu/Ni/Cu(001) is investigated using photoemission electron microscopy. While the (Fe/Ni) layer exhibits the SRT, the interlayer coupling of the perpendicularly magnetized Ni layer to the (Fe/Ni) layer serves as a virtual perpendicular magnetic field exerted on the (Fe/Ni) layer. We find that the perpendicular virtual magnetic field breaks the up-down symmetry of the (Fe/Ni) stripe domains to induce a net magnetization in the normal direction of the film. Moreover, as the virtual magnetic field increases to exceed a critical field, the stripe domain phase evolves into a bubble domain phase. Although the critical field depends on the Fe film thickness, we show that the area fraction of the minority domain exhibits a universal value that determines the stripe-to-bubble phase transition.

  18. Heterogeneous Catalysis on Atomically Dispersed Supported Metals: CO2 Reduction on Multifunctional Pd Catalysts

    SciTech Connect (OSTI)

    Kwak, Ja Hun; Kovarik, Libor; Szanyi, Janos

    2013-11-01T23:59:59.000Z

    Temperature programmed reaction and scanning transmission electron microscopy experiments were applied to prove the requirement of two different catalyst functionalities for the reduction of CO2 with hydrogen on Pd/Al2O3 and Pd/MWCNT catalysts. The research described in this paper was supported by the Laboratory Directed Research and Development (LDRD) program of the Pacific Northwest National Laboratory (PNNL) and was performed at the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at PNNL. PNNL is operated for the US DOE by Battelle Memorial Institute.

  19. Dynamical x-ray diffraction from an icosahedral Al-Pd-Mn quasicrystal

    SciTech Connect (OSTI)

    Kycia, S.

    1996-04-23T23:59:59.000Z

    Primary extinction effects in diffraction from single grains of Al-Pd- Mn, and presumably many other FCI alloys, may be significant and should be corrected for prior to use of diffraction data in structural determinations. Probes based on dynamical diffraction effects, such as x-ray standing wave fluorescence, multiple beam interference, and x-ray transmission topographs, may now be used to study the bulk and surface structure of some quasicrystals. The observation of dynamical diffraction from icosahedral Al-Pd-Mn is a striking confirmation of the fact that quasicrystals can present a degree of structural perfection comparable to that found in the best periodic intermetallic crystals.

  20. P(t) Dependence of Transverse Flow in Relativistic Heavy-Ion Collisions 

    E-Print Network [OSTI]

    Li, Bao-An; Ko, Che Ming; Li, GQ.

    1996-01-01T23:59:59.000Z

    OF TRANSVERS b . A slight increase in b or decrease in T results in a dra- matic increase in the ratio R(pt). These results indicate that the pt dependence of the ratio R(pt) indeed carries interest- ing information about the strength of transverse flow...(pt) at high transverse momenta. We now turn to our study using the relativisitc transport model ~ART 1.0! @15#. This model was developed by includ- ing more baryon and meson resonances as well as their in- teractions in the Boltzmann-Uehling-Uhlenbeck ~BUU...

  1. Sign change of exchange bias in [Pt/Co]{sub 3}/IrMn multilayer

    SciTech Connect (OSTI)

    Yoon, Seungha; Kwon, Joonhyun; Cho, B. K., E-mail: chobk@gist.ac.kr [School of Materials Science and Engineering, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712 (Korea, Republic of)

    2014-05-07T23:59:59.000Z

    The properties of exchange bias in a multilayer of [Pt(1.0?nm)/Co(1.0?nm)]{sub 2}/Pt(t{sub Pt} nm)/Co(1.0?nm)/ IrMn(12.0?nm) were investigated with a variation of Pt layer thickness, t{sub Pt}. For t{sub Pt}???1.6?nm, it was typically observed that Co layers were ferromagnetically coupled while IrMn layer exhibited negative exchange bias. With increasing Pt thickness, antiferromagnetic (AF) interlayer coupling strength increased and caused AF spin configuration between the Co layers. With further increasing of Pt thickness (t{sub Pt}?=?2.5?nm), the exchange bias between Co and IrMn layers was changed from negative to positive. Therefore, a large enhancement of AF interlayer coupling induced the sign change of exchange bias from negative to positive and resulted in a drastic change of switching behavior in a magnetization reversal. Both extraordinary Hall-effect and magnetoresistance were measured to verify the exchange bias direction and spin configurations upon magnetization reversal.

  2. The durability dependence of Pt/CNT electrocatalysts on the nanostruct...

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

    PEM fuel cells was investigated using cyclic voltammetry (CV, 0.6-1.1V) accelerated degradation test method. PtCNT catalysts were characterized with cyclic voltammograms,...

  3. 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.

  4. PT-symmetric quantum systems with positive P

    E-Print Network [OSTI]

    Miloslav Znojil; Hendrik B. Geyer

    2012-01-24T23:59:59.000Z

    A new version of PT-symmetric quantum theory is proposed and illustrated by an N-site-lattice Legendre oscillator. The essence of the innovation lies in the replacement of parity P (serving as an indefinite metric in an auxiliary Krein space) by its non-involutory alternative P(positive)=Q>0 playing the role of a positive-definite nontrivial metric in an auxiliary, redundant, unphysical Hilbert space. It is shown that the QT-symmetry of this form remains appealing and technically useful.

  5. Step- vs. kink-formation energies on Pt(111)

    SciTech Connect (OSTI)

    FEIBELMAN,PETER J.

    2000-05-01T23:59:59.000Z

    Ab-initio kink-formation energies are about 0.25 and 0.18 eV on the (100)- and (111)-microfacet steps of Pt(111), while the sum of the step-formation energies is 0.75 eV/atom. These results imply a specific ratio of formation energies for the two step types, namely 1.14, in excellent agreement with experiment. If kink-formation costs the same energy on the two step types, an inference recently drawn from scanning probe observations of step wandering, this ratio ought to be 1.

  6. Isospectral partners for a complex PT-invariant potential

    E-Print Network [OSTI]

    Anjana Sinha; Rajkumar Roychoudhury

    2002-05-20T23:59:59.000Z

    We construct isospectral partner potentials of a complex PT-invariant potential, viz., V(x) = V_1 sech ^2 x - i V_2 sech x tanh x using Darboux's method. Oneset of isospectral potentials are obatined which can be termed 'Satellite potentials', in the sense that they are pf the same form as the original potential. In a particular case, the supersymmetric partner potential has the same spectrum, including the zero energy ground state, a fact which cannot occur in conventional supersymmetric quantum mechanics with real potential. An explicit example of a non-trivial set of isospectral potential is also obtained.

  7. 23pt0GreeningtheGovernment.pdf | Department of Energy

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directed off Energy.gov. Are you sure you wantJoin us for|IdahotheWhat is3pt0GreeningtheGovernment.pdf

  8. Acqguide18pt0 March 2011 final | Department of Energy

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

    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 742Energy China 2015ofDepartmentDepartment of2 ofEmergency Acquisitions Acqguide18pt0 March 2011

  9. Electrodeposition of ultrathin Pd, Co and Bi films on well-defined noble-metal electrodes: studies by ultrahigh vacuum-electrochemistry (UHV-EC)

    E-Print Network [OSTI]

    Baricuatro, Jack Hess L

    2006-10-30T23:59:59.000Z

    admetal on a noble-metal surface; and (iii) Co on polycrystalline Pd and Pd(111), a reactive metal on a noble-metal surface. The interfacial electrochemistry of these prototypical systems was characterized using a combination of electrochemical methods...

  10. First principles investigation of the initial stage of H-induced missing-row reconstruction of Pd(110) surface

    SciTech Connect (OSTI)

    Padama, Allan Abraham B. [Department of Applied Physics, Osaka University, Suita, Osaka 565-0871 (Japan); Kasai, Hideaki, E-mail: kasai@dyn.ap.eng.osaka-u.ac.jp [Department of Applied Physics, Osaka University, Suita, Osaka 565-0871 (Japan); Center for Atomic and Molecular Technologies, Osaka University, Suita, Osaka 565-0871 (Japan)

    2014-06-28T23:59:59.000Z

    The pathway of H diffusion that will induce the migration of Pd atom is investigated by employing first principles calculations based on density functional theory to explain the origin of missing-row reconstruction of Pd(110).The calculated activation barrier and the H-induced reconstruction energy reveal that the long bridge-to-tetrahedral configuration is the energetically favored process for the initial stage of reconstruction phenomenon. While the H diffusion triggers the migration of Pd atom, it is the latter process that significantly contributes to the activated missing-row reconstruction of Pd(110). Nonetheless, the strong interaction between the diffusing H and the Pd atoms dictates the occurrence of reconstructed surface.

  11. The spin Hall angle and spin diffusion length of Pd measured by spin pumping and microwave photoresistance

    SciTech Connect (OSTI)

    Tao, X. D.; Feng, Z.; Miao, B. F.; Sun, L.; You, B.; Wu, D.; Du, J.; Zhang, W.; Ding, H. F., E-mail: hfding@nju.edu.cn [Department of Physics, National Laboratory of Solid State Microstructures, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)

    2014-05-07T23:59:59.000Z

    We present the experimental study of the spin Hall angle (SHA) and spin diffusion length of Pd with the spin pumping and microwave photoresistance effects. The Py/Pd bilayer stripes are excited with an out-of-plane microwave magnetic field. The pure spin current is thus pumped and transforms into charge current via the inverse spin Hall effect (ISHE) in Pd layer, yielding an ISHE voltage. The ISHE voltage can be distinguished from the unwanted signal caused by the anisotropic magnetoresistance according to their different symmetries. Together with Pd thickness dependent measurements of in and out-of-plane precessing angles and effective spin mixing conductance, the SHA and spin-diffusion length of Pd are quantified as 0.0056?±?0.0007 and 7.3?±?0.7?nm, respectively.

  12. NiW and NiRu Bimetallic Catalysts for Ethylene Steam Reforming: Alternative Mechanisms for Sulfur Resistance

    SciTech Connect (OSTI)

    Rangan, M.; Yung, M. M.; Medlin, J. W.

    2012-06-01T23:59:59.000Z

    Previous investigations of Ni-based catalysts for the steam reforming of hydrocarbons have indicated that the addition of a second metal can reduce the effects of sulfur poisoning. Two systems that have previously shown promise for such applications, NiW and NiRu, are considered here for the steam reforming of ethylene, a key component of biomass derived tars. Monometallic and bimetallic Al{sub 2}O{sub 3}-supported Ni and W catalysts were employed for ethylene steam reforming in the presence and absence of sulfur. The NiW catalysts were less active than Ni in the absence of sulfur, but were more active in the presence of 50 ppm H{sub 2}S. The mechanism for the W-induced improvements in sulfur resistance appears to be different from that for Ru in NiRu. To probe reasons for the sulfur resistance of NiRu, the adsorption of S and C{sub 2}H{sub 4} on several bimetallic NiRu alloy surfaces ranging from 11 to 33 % Ru was studied using density functional theory (DFT). The DFT studies reveal that sulfur adsorption is generally favored on hollow sites containing Ru. Ethylene preferentially adsorbs atop the Ru atom in all the NiRu (111) alloys investigated. By comparing trends across the various bimetallic models considered, sulfur adsorption was observed to be correlated with the density of occupied states near the Fermi level while C{sub 2}H{sub 4} adsorption was correlated with the number of unoccupied states in the d-band. The diverging mechanisms for S and C{sub 2}H{sub 4} adsorption allow for bimetallic surfaces such as NiRu that enhance ethylene binding without accompanying increases in sulfur binding energy. In contrast, bimetallics such as NiSn and NiW appear to decrease the affinity of the surface for both the reagent and the poison.

  13. Benchmark Problem: A PK/PD Model and Safety Constraints for Anesthesia Delivery

    E-Print Network [OSTI]

    Mitchell, Ian

    Benchmark Problem: A PK/PD Model and Safety Constraints for Anesthesia Delivery Victor Gan, Guy A of the goals of general anesthesia. In this brief paper we provide a differential equation model of how Introduction General anesthesia is a broad term encompassing the use of drugs to induce and maintain three

  14. Micro Catalytic Combustor with Pd/Nano-porous Alumina for High-Temperature Application

    E-Print Network [OSTI]

    Kasagi, Nobuhide

    Micro Catalytic Combustor with Pd/Nano-porous Alumina for High-Temperature Application Takashi: A micro-scale catalytic combustor using high-precision ceramic tape-casting technology has been developed surface reaction of butane. In combustion experiments with a prototype combustor, the wall temperature

  15. Chin. Phys. B Vol. 20, No. 11 (2011) 113301 Highly dispersed Pd nanoparticles on chemically

    E-Print Network [OSTI]

    Gao, Hongjun

    2011-01-01T23:59:59.000Z

    Chin. Phys. B Vol. 20, No. 11 (2011) 113301 Highly dispersed Pd nanoparticles on chemically modified graphene with aminophenyl groups for formic acid oxidation Yang Su-Dong( )a)b) , Shen Cheng functionalized by a nucleophilic ring-opening reaction between the epoxy groups of graphene oxide

  16. Hydrogen adsorption on Pd/TiFe (110) surface S.E. Kulkovaa

    E-Print Network [OSTI]

    Kim, Jai Sam

    Hydrogen adsorption on Pd/TiFe (110) surface S.E. Kulkovaa , S.V. Eremeeva,b,*, V.E. Egorushkinc February 2003 by E.L. Ivchenko Abstract Adsorption of hydrogen on the TiFe (110) surface covered the local density approximation. Influence of palladium coating to adsorption properties of the TiFe (110

  17. Highly ecient kinetic resolution of 2-cyclohexenyl acetate in Pd-catalyzed allylic alkylation

    E-Print Network [OSTI]

    Zhang, Xumu

    Highly ecient kinetic resolution of 2-cyclohexenyl acetate in Pd-catalyzed allylic alkylation James resolution of 2-cyclohexenyl acetate was observed during alkylation. In addition, the reactivity and enantioselectivity showed a strong dependence on the acetate salt with the BSA/MOAc (M=alkali metal) base system

  18. Sensors and Actuators B 49 (1998) 258267 Pd/PVDF thin film hydrogen sensor based on

    E-Print Network [OSTI]

    Mandelis, Andreas

    1998-01-01T23:59:59.000Z

    hydrogen detection, such as the process of lead- acid battery charging. As the hydrogen infrastructureSensors and Actuators B 49 (1998) 258­267 Pd/PVDF thin film hydrogen sensor based on laser Laboratories and Centre for Hydrogen and Electrochemical Studies, Uni6ersity of Toronto, 5 Kings College Road

  19. Edinburgh Research Explorer Quantifying the implicit process flow abstraction in SBGN-PD

    E-Print Network [OSTI]

    Millar, Andrew J.

    Edinburgh Research Explorer Quantifying the implicit process flow abstraction in SBGN-PD diagrams with Bio-PEPA Citation for published version: Loewe, L, Moodie, S & Hillston, J 2009, 'Quantifying & Hillston This work is licensed under the Creative Commons Attribution License. Quantifying the implicit

  20. Quantifying the implicit process flow abstraction in SBGN-PD diagrams with Bio-PEPA

    E-Print Network [OSTI]

    Loewe, Laurence; Hillston, Jane

    2009-01-01T23:59:59.000Z

    For a long time biologists have used visual representations of biochemical networks to gain a quick overview of important structural properties. Recently SBGN, the Systems Biology Graphical Notation, has been developed to standardise the way in which such graphical maps are drawn in order to facilitate the exchange of information. Its qualitative Process Diagrams (SBGN-PD) are based on an implicit Process Flow Abstraction (PFA) that can also be used to construct quantitative representations, which can be used for automated analyses of the system. Here we explicitly describe the PFA that underpins SBGN-PD and define attributes for SBGN-PD glyphs that make it possible to capture the quantitative details of a biochemical reaction network. We implemented SBGNtext2BioPEPA, a tool that demonstrates how such quantitative details can be used to automatically generate working Bio-PEPA code from a textual representation of SBGN-PD that we developed. Bio-PEPA is a process algebra that was designed for implementing quant...

  1. CO2 + CH4 Chemistry over Pd: Results of Kinetic Simulations Relevant to

    E-Print Network [OSTI]

    Spiteri, Raymond J.

    hydrogen (methane is `reformed' to synthesis gas or `syngas'). Rezaei et al. [3] reported the production of syngas by methane reforming on a number of transition metal surfaces. They attribute the relatively low efficacy of Pd for the syngas production by methane reforming to carbon deposits on the surface

  2. Form P&D initial interview | Faculty of Science |version January 2009 Page 1 of 3

    E-Print Network [OSTI]

    Hille, Sander

    ­ Password: leiden7 Applicable performance areas from the UFO profile Part B - Agreements the UFO profile, designated tasks, competencies and the personal development of the employee. For instance performance areas from the UFO profile. #12;Form P&D initial interview | Faculty of Science |version January

  3. 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

  4. Resonant two-photon ionization spectroscopy of jet-cooled PdC Jon D. Langenberg, Lian Shao, and Michael D. Morsea)

    E-Print Network [OSTI]

    Morse, Michael D.

    Resonant two-photon ionization spectroscopy of jet-cooled PdC Jon D. Langenberg, Lian Shao April 1999; accepted 21 May 1999 The first optical investigation of the spectra of diatomic PdC has of PdC, which is studied to add to the growing body of knowledge surrounding the tran- sition metal

  5. Transformation Induced Fatigue of Ni-Rich NiTi Shape Memory Alloy Actuators

    E-Print Network [OSTI]

    Schick, Justin Ryan

    2011-02-22T23:59:59.000Z

    TRANSFORMATION INDUCED FATIGUE OF NI-RICH NITI SHAPE MEMORY ALLOY ACTUATORS A Thesis by JUSTIN RYAN SCHICK Submitted to the O ce of Graduate Studies of Texas A&M University in partial ful llment of the requirements for the degree of MASTER... OF SCIENCE December 2009 Major Subject: Aerospace Engineering TRANSFORMATION INDUCED FATIGUE OF NI-RICH NITI SHAPE MEMORY ALLOY ACTUATORS A Thesis by JUSTIN RYAN SCHICK Submitted to the O ce of Graduate Studies of Texas A&M University in partial ful llment...

  6. Engineering the Martensitic Transformation Hysteresis of Ni-Rich NiTi Alloys 

    E-Print Network [OSTI]

    Franco, Brian Eelan

    2014-12-18T23:59:59.000Z

    Ti is an intermetallic compound that forms in the Ni-Ti system when the Ni content is between 49-57% (at%) [21]. Its structure can take three distinct forms depending on the temperature; the CsCl B2 structure, the trigonal R phase, and the 9 monoclinic B19....2.1. Thermodynamic aspects of the martensitic transformation The martensitic transformation occurs via nucleation and growth of martensite inside of the austenite matrix. The condition for nucleation of martensite is described by: = 0...

  7. PHYSICAL REVIEW B 89, 064307 (2014) Indirect heating of Pt by short-pulse laser irradiation of Au in a nanoscale Pt/Au bilayer

    E-Print Network [OSTI]

    Cahill, David G.

    -probe measurements and modeling using a transmission-line-equivalent circuit. For optical exciation of either the Pt excitations, which are then driven out of thermal equilibrium with the vibrations of the atomic lattice [1

  8. The effect of CoPt crystallinity and grain texturing on properties of exchange-coupled Fe/CoPt systems

    E-Print Network [OSTI]

    Rubloff, Gary W.

    /CoPt soft/hard magnetic systems was studied using gradient thickness multilayer thin films. We have studied/CoPt systems H. Oguchi,1,a A. Zambano,1 M. Yu,1,2 J. Hattrick-Simpers,1,5 D. Banerjee,1 Y. Liu,3 Z. L. Wang,3 J in hard/soft nanocomposite magnets. © 2009 American Institute of Physics. DOI: 10.1063/1.3068330 Magnetic

  9. Reactivity of a Thick BaO Film Supported on Pt(111): Adsorption...

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

    a Thick BaO Film Supported on Pt(111): Adsorption and Reaction of NO2, H2O and CO2. Reactivity of a Thick BaO Film Supported on Pt(111): Adsorption and Reaction of NO2, H2O and...

  10. CO2 sticking on Pt(111); the role of kinetic energy and internal degrees of freedom

    E-Print Network [OSTI]

    Persson, Mats

    CO2 sticking on Pt(111); the role of kinetic energy and internal, S-412 96, G"oteborg, Sweden Abstract CO2 adsorbed measurements of non-dissociative sticking coefficient, S0, of CO2 on the Pt(111) surfac* *e

  11. Mechanism of O2 Activation and Methanol Production by (Di(2-pyridyl)methanesulfonate)PtII

    E-Print Network [OSTI]

    Goddard III, William A.

    Mechanism of O2 Activation and Methanol Production by (Di(2- pyridyl)methanesulfonate)PtII Me observed for the SN2 functionalization to form methanol by two isomeric (dpms)PtIV Me(OH)2 complexes, one conversion of methane to methanol at low temper- ature is crucial for transportation of shale gas produced

  12. Performance of plasma sputtered Fuel Cell electrodes with ultra-low Pt M. Cavarroca

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Performance of plasma sputtered Fuel Cell electrodes with ultra-low Pt loadings M. Cavarroca , A. Abstract Ultra-low Pt content PEMFC electrodes have been manufactured using magnetron co- sputtering cell; Plasma sputtering deposition; ultra low platinum loading * Corresponding author: Fax: +33 2 38 41

  13. Novel Pt/Mg(In)(Al)O catalysts for ethane and propane dehydrogenation Pingping Sun a

    E-Print Network [OSTI]

    Iglesia, Enrique

    Novel Pt/Mg(In)(Al)O catalysts for ethane and propane dehydrogenation Pingping Sun a , Georges and propane dehydrogenation reactions are strongly dependent on the bulk In/Pt ratio. For both reactants to alkene was nearly 100%. Coke deposition was observed after catalyst use for either ethane or propane

  14. Investigation of microstructure, surface morphology, and hardness properties of PtIr films by magnetron sputtering

    SciTech Connect (OSTI)

    Lee, Chao-Te; Liu, Bo-Heng; Chang, Chun-Ming; Lin, Yu-Wei [Instrument Technology Research Center, National Applied Research Laboratories, Hsinchu 300, Taiwan (China)

    2010-09-15T23:59:59.000Z

    Pt{sub 1-x}Ir{sub x} films with x varying from 22.76 to 63.25 at. % are deposited on (100) Si wafer substrates at 400 deg. C by magnetron sputtering deposition. The effects of the Ir concentration on the microstructure, morphology, and hardness of PtIr films are investigated by field emission scanning electron microscopy, x-ray diffraction, atomic force microscopy, and nanoindentation system. The columnar structures are observed by field emission scanning electron microscopy. X-ray diffraction analysis reveals that PtIr films have preferred orientation along Pt(111) when the Ir concentration is below 50.84 at. %. When the Ir content is more than 50.84 at. %, the PtIr film shifts to another preferred orientation, Ir(111). The surface morphology is analyzed by atomic force microscopy. The roughness of the PtIr films decreases with increasing Ir content. The hardness of all the PtIr films is below 20 GPa. The maximum hardness of the PtIr films is about 14.9 GPa when the Ir concentration is 57.9 at. %.

  15. A organizao interna do PT no Governo Lula: os vnculos com a sociedade

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    A organização interna do PT no Governo Lula: os vínculos com a sociedade Oswaldo E. do Amaral. halshs-00496150,version1-29Jun2010 #12;2 A organização interna do PT no Governo Lula: os vínculos com década de 90 e ao assumir o comando do Governo Federal pela primeira vez em 2003. O artigo mostra, por

  16. Proton inelastic scattering on {sup 56}Ni in inverse kinematics

    SciTech Connect (OSTI)

    Kraus, G.; Egelhof, P.; Fischer, C.; Geissel, H.; Himmler, A.; Nickel, F.; Muenzenberg, G.; Schwab, W.; Weiss, A. [GSI, Darmstadt (Germany); Chulkov, L.; Golovkov, M.; Ogloblin, A. [I.V. Kurchatov Inst., Moscow (Russian Federation); Friese, J.; Gillitzer, A.; Koerner, H.J.; Peter, M. [TU, Munich (Germany); Henning, W.; Schiffer, J.P. [Argonne National Lab., IL (United States); Kratz, J.V. [Univ. of Mainz (Germany)

    1993-10-01T23:59:59.000Z

    Inelastic proton scattering to the first excited 2{sup +} state at 2.701 MeV in doubly magic {sup 56}Ni was studied at 101 MeV/u in inverse kinematics. The radioactive {sup 56}Ni ion beam was obtained from the SIS heavy ion synchrotron at GSI Darmstadt via fragmentation of a {sup 58}Ni beam, and separation by the fragment separator (FRS). A value B(E2, 0{sup +} {yields} 2{sup +}) = 600 {+-} 120 e{sup 2} fm{sup 4} was obtained which corresponds to a deformation parameter {beta} ({sup 56}Ni) = 0.173 {+-} 0.017.

  17. Fusion of radioactive $^{132}$Sn with $^{64}$Ni

    E-Print Network [OSTI]

    J. F. Liang; D. Shapira; J. R. Beene; C. J. Gross; R. L. Varner; A. Galindo-Uribarri; J. Gomez del Campo; P. A. Hausladen; P. E. Mueller; D. W. Stracener; H. Amro; J. J. Kolata; J. D. Bierman; A. L. Caraley; K. L. Jones; Y. Larochelle; W. Loveland; D. Peterson

    2007-04-05T23:59:59.000Z

    Evaporation residue and fission cross sections of radioactive $^{132}$Sn on $^{64}$Ni were measured near the Coulomb barrier. A large sub-barrier fusion enhancement was observed. Coupled-channel calculations including inelastic excitation of the projectile and target, and neutron transfer are in good agreement with the measured fusion excitation function. When the change in nuclear size and shift in barrier height are accounted for, there is no extra fusion enhancement in $^{132}$Sn+$^{64}$Ni with respect to stable Sn+$^{64}$Ni. A systematic comparison of evaporation residue cross sections for the fusion of even $^{112-124}$Sn and $^{132}$Sn with $^{64}$Ni is presented.

  18. Computing Free Energy Landscapes: Application to Ni-based Electrocatal...

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

    Computing Free Energy Landscapes: Application to Ni-based Electrocatalysts with Pendant Amines for H2 Production and Oxidation. Computing Free Energy Landscapes: Application to...

  19. Physical and biological properties of a Pt(ll) complex of a beta-diketiminate ligand with pendant quinoline arms

    E-Print Network [OSTI]

    Hope, Jennifer M

    2012-01-01T23:59:59.000Z

    A monoanionic, tetradentate [beta]-diketiminate (BDI) ligand with pendant quinoline arms, BDIQQH was coordinated to Pt(II) to yield the square-planar complex [Pt(BDIQQ)]CI. This complex was characterized by NMR spectroscopy, ...

  20. Determination of the Pt spin diffusion length by spin-pumping and spin Hall effect

    SciTech Connect (OSTI)

    Zhang, Wei; Pearson, John E.; Hoffmann, Axel [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)] [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Vlaminck, Vincent [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States) [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Colegio de Ciencias e Ingenería, Universidad San Fransciso de Quito, Quito (Ecuador); Divan, Ralu [Center for Nanoscale Materials, Argonne National Laboratory, Illinois 60439 (United States)] [Center for Nanoscale Materials, Argonne National Laboratory, Illinois 60439 (United States); Bader, Samuel D. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States) [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Center for Nanoscale Materials, Argonne National Laboratory, Illinois 60439 (United States)

    2013-12-09T23:59:59.000Z

    The spin diffusion length of Pt at room temperature and at 8 K is experimentally determined via spin pumping and spin Hall effect in permalloy/Pt bilayers. Voltages generated during excitation of ferromagnetic resonance from the inverse spin Hall effect and anisotropic magnetoresistance effect were investigated with a broadband approach. Varying the Pt layer thickness gives rise to an evolution of the voltage line shape due to the superposition of the above two effects. By studying the ratio of the two voltage components with the Pt layer thickness, the spin diffusion length of Pt can be directly extracted. We obtain a spin diffusion length of ?1.2 nm at room temperature and ?1.6 nm at 8 K.

  1. $J/?$ suppression in Pb+Pb collisions and $p_T$ broadening

    E-Print Network [OSTI]

    A. K. Chaudhuri

    2003-04-10T23:59:59.000Z

    We have analysed the NA50 data, on the centrality dependence of $p_T$ broadening of $J/\\psi$'s, in Pb+Pb collisions, at the CERN-SPS. The data were analysed in a QCD based model, where $J/\\psi$'s are suppressed in 'nuclear' medium. Without any free parameter, the model could explain the NA50 $p_T$ broadening data. The data were also analysed in a QGP based threshold model, where $J/\\psi$ suppression is 100% above a critical density. The QGP based model could not explain the NA50 $p_T$ broadening data. We have also predicted the centrality dependence of $J/\\psi$ suppression and $p_T$ broadening at RHIC energy. Both the models, the QGP based threshold model and the QCD based nuclear absorption model, predict $p_T$ broadening very close to each other.

  2. FePt-based exchange-coupled composite perpendicular recording media.

    SciTech Connect (OSTI)

    Sun, C.; Stafford, D.; Acharya, R.; X-Ray Science Division; Western Digital Media

    2010-06-01T23:59:59.000Z

    In order to demonstrate the strong and proper exchange coupling between bottom magnetic layer and capping magnetic layer in FePt-based exchange-coupled composite (ECC) perpendicular recording media, we have investigated the thermal stability, writability, degree of exchange coupling, and ECC gain factor of FePt-based ECC media as a function of the thickness of the capping FePt layer. With increasing the thickness of capping FePt layer, both thermal stability and media writability increase simultaneously as a result of the change from strong exchange coupling to proper exchange coupling. The proper exchange-coupled FePt ECC is a promising candidate for future high-density perpendicular recording.

  3. The bioinorganic chemistry of N2S2 metal complexes: reactivity and ligating ability

    E-Print Network [OSTI]

    Golden, Melissa Lynn

    2005-08-29T23:59:59.000Z

    in its diazacycle backbone ring producing subtle differences in N2S2Ni geometry. Metallation of Ni-1?? with PdCl2, Pd(NO3)2, and NiBr2 produced three structural forms: Ni2Pd basket, Ni4Pd2 C4-paddlewheel, and Ni3 slant chair. In attempts to provide a...

  4. Comparison of monolith-supported metals for the direct oxidation of methane of syngas

    SciTech Connect (OSTI)

    Torniainen, P.M.; Chu, X.; Schmidt, L.D. (Univ. of Minnesota, Minneapolis (United States))

    1994-03-01T23:59:59.000Z

    The partial oxidation of CH[sub 4] in O[sub 2] near atmospheric pressure to produce syngas was investigated on monolith-supported Rh, Ni, Pt, Ir, Pd, Pd-La[sub 2]O[sub 3], Fe, Co, Re, and Ru catalysts in an autothermal flow reactor at residence times of [approximately]10 msec (GHSV [approximately] 100,000 hr[sup [minus]1]). Optimal CH[sub 4] conversion and CO and H[sub 2] selectivities of 0.89, 0.95, and 0.90, respectively, were achieved on Rh at 1000[angstrom]C with no loss in activity over many hours. Ni showed similar conversion and selectivities but deactivated. Experiments with up to 25 vol% H[sub 2]O added to the feed showed little evidence of the occurrence of steam reforming and water-gas shift reactions. Pt and Ir sustained stable reaction but a lower selectivities and conversion than Rh or Ni. Pd, Pd-La[sub 2]O[sub 3], and Co deactivated rapidly, while Re, Ru, and Fe would not sustain autothermal reaction. Ni and Re deactivated by volatilization and metal loss, while Pd-La[sub 2]O[sub 3] deactivated by carbon formation, and Pd deactivated by a combination of metal loss and carbon formation. Pd produced up to 14% selectivity to C[sub 2]H[sub 4] and C[sub 2]H[sub 4] and C[sub 2]H[sub 6], Pd-La[sub 2]O[sub 3] up to 5%, Pt [approximately] 1%, and other metals less than 0.2%. 10 refs., 5 figs., 1 tab.

  5. Wide magnetic field range of Ni-P/PZT/Ni-P cylindrical layered magnetoelectric composites

    E-Print Network [OSTI]

    Volinsky, Alex A.

    magnetoelectric (ME) composites were prepared by electroless deposition. The Ni-P layer has an amorphous with epoxy,5 electrodeposition,6,7 and electroless deposition.8,9 The objective and the develop- ment trend films with good interfacial bonding.12 Nickel is a kind of conventional magnetic material suitable

  6. Catalytic decomposition of Ba(NO3)2 on Pt(111)

    SciTech Connect (OSTI)

    Mudiyanselage, Kumudu; Weaver, Jason F.; Szanyi, Janos

    2011-04-07T23:59:59.000Z

    The decomposition of Ba(NO3)2 formed on BaO/Pt(111) (Pt(111) surface is partially covered by BaO) in the presence of CO was studied using temperature programmed desorption (TPD), infrared reflection absorption (IRA) and X-ray photoelectron (XP) spectroscopies. The exposure of BaO/Pt(111) to elevated NO2 pressure (1.0×10-4 Torr) at 450 K leads to the formation of Ba(NO3)2, chemisorbed O (OPt) and Pt-oxide-like domains. During TPD, the Ba(NO3)2 begins to thermally decompose near 490 K, releasing NO and NO2 with the maximum NOx desorption rate seen at 605 K. The OPt species formed following the exposure of BaO/Pt(111) to NO2 react with CO to release CO2 at 450 K. The consumption of OPt during CO oxidation initiates the migration of O from the Pt-oxide-like domains to the chemisorbed phase, where the CO oxidation reaction occurs. Therefore, the removal of OPt by CO leads to the reduction of oxidized Pt, and to the formation of metallic Pt(111) domains, where, subsequently, catalytic decomposition of Ba(NO3)2 can take place. The Pt-catalyzed decomposition of Ba(NO3)2 occurs readily at 450 K, a temperature much lower than the onset of the decomposition temperature of Ba(NO3)2 in the presence of oxidized Pt. This work was supported by the US Department of Energy Basic Energy Sciences' Chemical Sciences, Geosciences & Biosciences Division. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  7. Epitaxial growth of NiTiO3 with a distorted ilmenite structure...

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

    growth of NiTiO3 with a distorted ilmenite structure. Epitaxial growth of NiTiO3 with a distorted ilmenite structure. Abstract: MTiO3 (M Fe, Mn, Ni) compounds have received...

  8. ag ni zn-addition: Topics by E-print Network

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

    Summary: Recent research shows that the resistance switching characteristics of NiO thin film, in combinations conversion into NiSi using Ni-AMD, and discuss the chemistry of...

  9. Ni(II) Salts and 2-Propanol Effect Catalytic Reductive Coupling of Epoxides and Alkynes

    E-Print Network [OSTI]

    Beaver, Matthew G.

    A Ni-catalyzed reductive coupling of alkynes and epoxides using Ni(II) salts and simple alcohol reducing agents is described. Whereas previously reported conditions relied on Ni(cod)2 and Et3B, this system has several ...

  10. Morphology and composition of Ni-Co electrodeposited powders

    SciTech Connect (OSTI)

    Maksimovic, V.M., E-mail: vesnam@vinca.rs [Institute of Nuclear Sciences, 'Vinca', University of Belgrade, 11001 Belgrade, P. O. Box 522 (Serbia); Lacnjevac, U.C. [Institute for Multidisciplinary research, University of Belgrade, P.O. Box 33, 11030 Belgrade (Serbia); Stoiljkovic, M.M. [Institute of Nuclear Sciences, 'Vinca', University of Belgrade, 11001 Belgrade, P. O. Box 522 (Serbia); Pavlovic, M.G. [Institute of Electrochemistry, ICTM, University of Belgrade, 11000 Belgrade, Njegoseva 12 (Serbia); Jovic, V.D. [Institute for Multidisciplinary research, University of Belgrade, P.O. Box 33, 11030 Belgrade (Serbia)

    2011-12-15T23:59:59.000Z

    The morphology, phase and chemical composition of Ni-Co alloy powders electrodeposited from an ammonium sulfate-boric acid containing electrolyte with different ratio of Ni/Co ions were investigated. The ratios of Ni/Co ions were 1/1, 1/2 and 1/3. The morphology, chemical composition and phase composition of the electrodeposited alloy powders were investigated using AES, SEM, EDS and XRD analysis. Composition of the electrolyte, i.e. the ratio of Ni/Co concentrations was found to influence both, the alloy phase composition and the morphology of Ni-Co alloy powders. At the highest ratio of Ni/Co = 1/1 concentrations typical 2D fern-like dendritic particles were obtained. With a decrease of Ni/Co ions ratio among 2D fern-like dendrites, 3D dendrites and different agglomerates were obtained. X-ray diffraction studies showed that the alloy powders mainly consisted of the face-centered cubic {alpha}-nickel phase and hexagonal close-packed {epsilon}-cobalt phase and minor proportions of face-centered cubic {alpha}-cobalt phase. The occurrence of the latter phase was observed only in the alloy powder with the higher cobalt concentration in electrolyte. The electrodeposition of Ni-Co powders occurred in an anomalous manner. - Highlights: Black-Right-Pointing-Pointer Ni-Co alloys powders were successfully electrodeposited. Black-Right-Pointing-Pointer Composition of the electrolyte (Ni/Co ions ratio) was found to influence on morphology of powders. Black-Right-Pointing-Pointer The electrodeposition of Ni-Co powders occurred in an anomalous manner.

  11. Sputter-Deposited Pt/CrN Nanoparticle PEM Fuel Cell Cathodes: Limited Proton Conductivity Through Electrode

    E-Print Network [OSTI]

    Gall, Daniel

    and power density.1 One obstacle to the widespread commercialization of fuel cells is the high cost activity than Pt,10 but is an attractive can- didate to supplement or replace Pt in lower cost fuel cellSputter-Deposited Pt/CrN Nanoparticle PEM Fuel Cell Cathodes: Limited Proton Conductivity Through

  12. Effect of surface composition of Pt-Au alloy cathode catalyst on the performance of direct methanol fuel cells

    E-Print Network [OSTI]

    Zhao, Tianshou

    Effect of surface composition of Pt-Au alloy cathode catalyst on the performance of direct methanol 2010 Available online 12 June 2010 Keywords: Fuel cell Direct methanol fuel cell Catalyst Active Site Pt-Au alloy a b s t r a c t A pure Pt cathode catalyst in direct methanol fuel cells is not only

  13. Microscale Investigations of Ni Uptake by Cement Using a

    E-Print Network [OSTI]

    Microscale Investigations of Ni Uptake by Cement Using a Combination of Scanning Electron Laboratory, IMX, Ecole Polytechnique Fe´de´ral de Lausanne (EPFL), 1015 Lausanne, Switzerland Cement is used-level radioactive waste. In this study, Ni uptake by hardened cement paste has been investigated with the aim

  14. Lanthanide Al-Ni base Ericsson cycle magnetic refrigerants

    DOE Patents [OSTI]

    Gschneidner, K.A. Jr.; Takeya, Hiroyuki

    1995-10-31T23:59:59.000Z

    A magnetic refrigerant for a magnetic refrigerator using the Ericsson thermodynamic cycle comprises DyAlNi and (Gd{sub 0.54}Er{sub 0.46})AlNi alloys having a relatively constant {Delta}Tmc over a wide temperature range. 16 figs.

  15. Transition voltages of vacuum-spaced and molecular junctions with Ag and Pt electrodes

    SciTech Connect (OSTI)

    Wu, Kunlin; Bai, Meilin; Hou, Shimin, E-mail: smhou@pku.edu.cn [Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871 (China); Sanvito, Stefano [School of Physics, AMBER and CRANN Institute, Trinity College, Dublin 2 (Ireland)

    2014-07-07T23:59:59.000Z

    The transition voltage of vacuum-spaced and molecular junctions constructed with Ag and Pt electrodes is investigated by non-equilibrium Green's function formalism combined with density functional theory. Our calculations show that, similarly to the case of Au-vacuum-Au previously studied, the transition voltages of Ag and Pt metal-vacuum-metal junctions with atomic protrusions on the electrode surface are determined by the local density of states of the p-type atomic orbitals of the protrusion. Since the energy position of the Pt 6p atomic orbitals is higher than that of the 5p/6p of Ag and Au, the transition voltage of Pt-vacuum-Pt junctions is larger than that of both Ag-vacuum-Ag and Au-vacuum-Au junctions. When one moves to analyzing asymmetric molecular junctions constructed with biphenyl thiol as central molecule, then the transition voltage is found to depend on the specific bonding site for the sulfur atom in the thiol group. In particular agreement with experiments, where the largest transition voltage is found for Ag and the smallest for Pt, is obtained when one assumes S binding at the hollow-bridge site on the Ag/Au(111) surface and at the adatom site on the Pt(111) one. This demonstrates the critical role played by the linker-electrode binding geometry in determining the transition voltage of devices made of conjugated thiol molecules.

  16. Beneficial compressive strain for oxygen reduction reaction on Pt (111) surface

    SciTech Connect (OSTI)

    Kattel, Shyam; Wang, Guofeng, E-mail: guw8@pitt.edu [Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261 (United States)

    2014-09-28T23:59:59.000Z

    We investigated the influence of compressive surface strain on the progression of oxygen reduction reaction (ORR) on Pt(111) surface using the density functional theory (DFT) calculation method. Specifically, we calculated the binding energies of all the chemical species possibly involved in ORR and the reaction energies (heat of reaction and activation energy) of all the possible ORR elementary reactions on the Pt(111) surfaces with ?2% and ?3% strain. Our DFT results indicate that all the ORR species bind more weakly on the compressively strained surfaces than on an unstrained surface owing to strain-induced d-electron band broadening. Our DFT calculations further predict that both OOH dissociation and HOOH dissociation pathways could be active for ORR on the Pt(111) surface with compressive strain between ?2% and ?3%. Moreover, the activation energies of the ORR rate-determining steps on the compressively strained Pt(111) surfaces were found to be lower than that on the unstrained Pt(111) surface. It was thus inferred that a ?2% to ?3% surface strain could lead to enhanced ORR activity on the Pt(111) catalysts. Consequently, our study suggests that tuning surface strain is an effective way to improve the performance of Pt-based electrocatalysts for ORR.

  17. Hydrides of CeNi/sub 5/, MmNi/sub 5/, Ca/sub 0/ /sub 2/(Ce/sub 0/ /sub 65/Mm/sub 0/ /sub 35/)/sub 0/ /sub 8/Ni/sub 5/, Ca/sub 0/ /sub 2/Ce/sub 0/ /sub 8/Ni/sub 5/, Ca/sub 0/ /sub 2/Mm/sub 0/ /sub 8/Ni/sub 5/, and mixed CeNi/sub 5//MmNi/sub 5/

    SciTech Connect (OSTI)

    Lakner, J.F.; Chow, T.S.

    1982-09-01T23:59:59.000Z

    Six intermetallic alloys (CeNi/sub 5/, MmNi/sub 5/, Ca/sub 0/ /sub 2/(Ce/sub 0/ /sub 65/Mm/sub 0/ /sub 35/)/sub 0/ /sub 8/Ni/sub 5/, Ca/sub 0/ /sub 2/Ce/sub 0/ /sub 8/Ni/sub 5/, Ca/sub 0/ /sub 2/Mm/sub 0/ /sub 8/Ni/sub 5/, and a mixed alloy, CeNi/sub 5//MmNi/sub 5/) were investigated with respect to their suitability to provide high hydrogen capacity and their potential for use in providing substantial hydrogen pressure at both low and high temperatures. A second phase of our investigation dealt with ball-milling and hydriding and dehydriding cycles to produce fine particles for use in hydride powder transfer studies. A summary of several Van't Hoff plots is also included for hydride-forming alloys.

  18. Fabrication of size-selected Pd nanoclusters using a magnetron plasma sputtering source

    SciTech Connect (OSTI)

    Ayesh, A. I.; Qamhieh, N.; Ghamlouche, H.; Thaker, S.; El-Shaer, M. [Department of Physics, United Arab Emirates University, Al Ain, P.O. Box 17551 (United Arab Emirates)

    2010-02-15T23:59:59.000Z

    We report on the fabrication of palladium (Pd) nanoclusters using a dc magnetron sputtering source. Plasma sputtering vaporizes the target's material forming nanoclusters by inert gas condensation. The sputtering source produces ionized nanoclusters that enable the study of the nanoclusters' size distribution using a quadrupole mass filter. In this work, the dependence of Pd nanoclusters' size distribution on various source parameters, such as the sputtering discharge power, inert gas flow rate, and aggregation length have been investigated. This work demonstrates the ability of tuning the palladium nanoclusters' size by proper optimization of the source operation conditions. The experimental nanocluster sizes are compared with a theoretical model that reveals the growth of large nanoclusters from 'embryos' by a two-body collision. The model is valid for a specific range of deposition parameters (low inert gas flow rates and aggregation lengths equal or below 70 mm).

  19. Marinescu, Nishimata, Mohr, and Stoltz: Homogeneous Pd-Catalyzed Enantioselective Decarboxylative Protonation SI 1 Supporting Information for

    E-Print Network [OSTI]

    Stoltz, Brian M.

    from Acros and used as received. Meldrum's acid was recrystallized from ethyl acetate prior to use (Table 1) The reactions were carried out using the following sample procedure. O CO2allyl Pd2(dba)3 (5

  20. Pd-Catalyzed O-Arylation of Ethyl Acetohydroximate: Synthesis of O-Arylhydroxylamines and Substituted Benzofurans

    E-Print Network [OSTI]

    Maimone, Thomas

    An efficient Pd catalyst for the O-arylation of ethyl acetohydroximate with aryl chlorides, bromides, and iodides has been developed. Ethyl acetohydroximate serves as an efficient hydroxylamine equivalent for C?O cross-coupling, ...

  1. Diastereo- and Enantioselective Pd(II)-Catalyzed Additions of 2-Alkylazaarenes to N-Boc Imines and Nitroalkenes 

    E-Print Network [OSTI]

    Best, Daniel; Kujuwa, Szymon; Lam, Hon Wai

    A chiral Pd(II)–bis(oxazoline) complex was found to be highly effective in promoting the first direct diastereo- and enantioselective addition of alkylazaarenes to N-Boc aldimines and nitroalkenes under mild conditions. Deprotection of Boc...

  2. Mechanism of coercivity enhancement by Ag addition in FePt-C granular films for heat assisted magnetic recording media

    SciTech Connect (OSTI)

    Varaprasad, B. S. D. Ch. S.; Takahashi, Y. K., E-mail: takahashi.yukiko@nims.go.jp; Wang, J.; Hono, K. [National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Ina, T.; Nakamura, T.; Ueno, W.; Nitta, K.; Uruga, T. [Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

    2014-06-02T23:59:59.000Z

    We investigated the Ag distribution in a FePtAg-C granular film that is under consideration for a heat assisted magnetic recording medium by aberration-corrected scanning transmission electron microscope-energy dispersive X-ray spectroscopy and X-ray absorption fine structure. Ag is rejected from the core of FePt grains during the deposition, forming Ag-enriched shell surrounding L1{sub 0}-ordered FePt grains. Since Ag has no solubility in both Fe and Pt, the rejection of Ag induces atomic diffusions thereby enhancing the kinetics of the L1{sub 0}-order in the FePt grains.

  3. Synthesis of Methanol and Dimethyl Ether from Syngas over Pd/ZnO/Al2O3 Catalysts

    SciTech Connect (OSTI)

    Lebarbier, Vanessa MC; Dagle, Robert A.; Kovarik, Libor; Lizarazo Adarme, Jair A.; King, David L.; Palo, Daniel R.

    2012-10-01T23:59:59.000Z

    A Pd/ZnO/Al2O3 catalyst was developed for the synthesis of methanol and dimethyl ether (DME) from syngas. Studied were temperatures of operation ranging from 250°C to 380°C. High temperatures (e.g. 380°C) are necessary when combining methanol and DME synthesis with a methanol to gasoline (MTG) process in a single reactor bed. A commercial Cu/ZnO/Al2O3 catalyst, utilized industrially for the synthesis of methanol at 220-280°C, suffers from a rapid deactivation when the reaction is conducted at high temperature (>320°C). On the contrary, a Pd/ZnO/Al2O3 catalyst was found to be highly stable for methanol and DME synthesis at 380°C. The Pd/ZnO/Al2O3 catalyst was thus further investigated for methanol and DME synthesis at P=34-69 bars, T= 250-380°C, GHSV= 5 000-18 000 h-1, and molar feeds H2/CO= 1, 2, and 3. Selectivity to DME increased with decreasing operating temperature, and increasing operating pressure. Increased GHSV’s and H2/CO syngas feed ratios also enhanced DME selectivity. Undesirable CH4 formation was observed, however, can be minimized through choice of process conditions and by catalyst design. By studying the effect of the Pd loading and the Pd:Zn molar ratio the formulation of the Pd/ZnO/Al2O3 catalyst was optimized. A catalyst with 5% Pd and a Pd:Zn molar ratio of 0.25:1 has been identified as the preferred catalyst. Results indicate that PdZn particles are more active than Pdº particles for the synthesis of methanol and less active for CH4 formation. A correlation between DME selectivity and the concentration of acid sites of the catalysts has been established. Hence, two types of sites are required for the direct conversion of syngas to DME: 1) PdZn particles are active for the synthesis of methanol from syngas, and 2) acid sites which are active for the conversion of methanol to DME. Additionally, CO2 formation was problematic as PdZn was found to be active for the water-gas-shift (WGS) reaction, under all the conditions evaluated.

  4. COMMENTS ON ANOMALOUS EFFECTS IN CHARGING OF PD POWDERS WITH HIGH DENSITY HYDROGEN ISOTOPES

    SciTech Connect (OSTI)

    Shanahan, K.

    2009-10-01T23:59:59.000Z

    In Kitamura, et al, Pd-containing materials are exposed to isotopes of hydrogen and anomalous results obtained. These are claimed to be a replication of another experiment conducted by Arata and Zhang. Erroneous basic assumptions are pointed out herein that alter the derived conclusions significantly. The final conclusion is that the reported results are likely normal chemistry combined with noise. Thus the claim to have proven that cold fusion is occurring in these systems is both premature and unlikely.

  5. Kinetics of the reduction of methyl viologen with hydrogen on a colloidal Pt catalyst

    SciTech Connect (OSTI)

    Maier, V.E.; Shafirovich, V.Ya.

    1988-10-01T23:59:59.000Z

    The evolution of H/sub 2/ on a Pt catalyst under the influence of one-electron reductors is part of the photocatalytic process of decomposition of H/sub 2/O into H/sub 2/ and O/sub 2/. As a model reaction we selected the reduction of methyl viologen. The bonding constant for hydrogen on colloidal Pt, as well as the effective rate constant of the heterolytic splitting of H/sub 2/ on the same Pt catalyst are determined. A mathematical description of the reduction of methyl viologen with hydrogen is suggested.

  6. Absence of topological insulator phases in non-Hermitian PT-symmetric Hamiltonians

    SciTech Connect (OSTI)

    Hu Yichen; Hughes, Taylor L. [Department of Physics, University of Illinois, 1110 West Green St., Urbana, Illinois 61801 (United States)

    2011-10-15T23:59:59.000Z

    In this work, we consider a generalization of the symmetry classification of topological insulators to non-Hermitian Hamiltonians, which satisfy a combined PT symmetry (parity and time reversal). We show via examples and explicit proofs from separate bulk and gapless boundary-state perspectives that the typical paradigm of forming topological insulator states from Dirac Hamiltonians is not compatible with the construction of non-Hermitian PT-symmetric Hamiltonians. The topological insulator states are PT-breaking phases and have energy spectra that are complex (not real) and, thus, are not consistent quantum theories.

  7. Absence of topological insulator phases in non-Hermitian PT-symmetric Hamiltonians

    E-Print Network [OSTI]

    Yi Chen Hu; Taylor L. Hughes

    2011-07-06T23:59:59.000Z

    In this work we consider a generalization of the symmetry classification of topological insulators to non-Hermitian Hamiltonians which satisfy a combined $PT$-symmetry (parity and time-reversal). We show via examples, and explicit bulk and boundary state proofs that the typical paradigm of forming topological insulator states from Dirac Hamiltonians is not compatible with the construction of non-Hermitian $PT$-symmetric Hamiltonians. The topological insulator states are $PT$-breaking phases and have energy spectra which are complex (not real) and thus such non-Hermitian Hamiltonians are not consistent quantum theories.

  8. Characterization of spin pumping effect in Permalloy/Cu/Pt microfabricated lateral devices

    SciTech Connect (OSTI)

    Yamamoto, Tatsuya, E-mail: tyamamoto@imr.tohoku.ac.jp; Seki, Takeshi; Takanashi, Koki [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Ono, Shimpei [Central Research Institute of Electric Power Industry, Tokyo 201-8511 (Japan)

    2014-05-07T23:59:59.000Z

    We studied ferromagnetic resonance (FMR) for microfabricated lateral devices consisting of a Permalloy (Py) rectangular element and a Pt nano-element bridged by a Cu wire, which were located on a coplanar waveguide. A change in the resonance linewidth (?f) was observed in the FMR spectra when the distance between Py and Pt (d) was varied. For devices with d?Pt.

  9. ANGLE-RESOLVED PHOTOEMISSION STUDIES OF Ag, Au, AND Pt

    SciTech Connect (OSTI)

    Davis, R.F.; Mills, K.A.; Thornton, G.; Kevan, S.D.; Shirley, D.A.

    1980-06-01T23:59:59.000Z

    An important question regarding the technique of angle-resolved photoemission (ARP) is the extent to which it can be used to determine experimental valence-band dispersion relations E{sub i}({rvec k}) for single crystalline solids. In the case of the 3d and 4d transition metals, studies of copper, nickel, palladium, and silver, show that a model based on the assumption of direct interband transitions (direct-transition model) may be used, in conjunction with an appropriate final-state dispersion relation E{sub f}({rvec k}), to elucidate E{sub i}({rvec k}) for these materials along several high symmetry lines (primarily {Gamma}{Lambda}L) in k-space. To answer this question more generally, we have undertaken an extensive study of the valence band structures of other transition metals along various k-space lines. To date, studies have been extended to the (111) faces of the 5d metals Pt and Au along with the Pt(100) ((5 x 20) surface structure) face, and the (110) and (100) faces of Ag. The experiments were all conducted at SSRL, using synchrotron radiation in the range 6 eV < h{nu} < 34 eV. The results of these studies, combined with our previous Ag(111) work at these energies, allow us to invoke important conclusions concerning the relationships between ARP data, E{sub i}({rvec k}) and E{sub f}({rvec k}) for these materials. Several are summarized. For each crystal face investigated, the direct-transition model, along with a simple quasi-free-electron E{sub f}({rvec k}), was sufficient to determine experimental E{sub i}({rvec k}) relations along the appropriate k-space line that were in general agreement with theoretical RAPW band structure calculations. Essentially, we required E{sub f}({rvec k}) to be of the form (h{sup 2}/2m*)|{rvec k} + {rvec G}|{sup 2} + V{sub o}, where {rvec G} is a reciprocal lattice vector, fitting this relation to the appropriate calculated bulk conduction band near the center of the line under investigation, with the inner potential V{sub o} and the reduced mass m* as free parameters. An additional shift of V{sub o} was necessary for Ag(110) and Pt(100) data, to obtain better agreement with theoretical bands. While generally excellent agreement between experimental and theoretical bands was found for Ag, as was the case for other 3d and 4d metals, substantial disagreement was observed for Pt and Au in parts of the Brillouin zone. This is probably an indication that further theoretical work is needed for these more complicated elements. The agreement in Ag is illustrated by Fig. 1, where experimental and theoretical bands are compared for all three high-symmetry directions. The determinations of E{sub i}({rvec k}) for the {Lambda} directions were relatively simple because peaks in the ARP spectra of (111) faces were essentially all attributable to primary direct transition. However, the {Sigma}, {Sigma}{prime}, and {Delta} directions were complicated by secondary emission peaks and dispersionless density-of-states (DOS) features in the spectra of the (100) and (110) faces. Peak intensity resonances associated with the bulk conduction band structure near {Lambda} were observed for each crystal face, and these simplified the assignment of peaks in the ARP spectra. The relationship between these resonances, which appear to be rather general phenomena, and E{sub f}({rvec k}), will be discussed. In summary, it is clear from these and other studies that the ARP technique, in conjunction with the direct-transition model, is generally applicable to valence band mapping in single crystals, provided that a suitable final-state dispersion relation can be calculated. However, complications like those observed in the ARP spectra of Ag, Pt, and Au may make the determination of E{sub i}({rvec k}) relations considerably more difficult for more complicated systems.

  10. Metal-and hydrogen-bonding competition during water absorption on Pd(111) and Ru(0001)

    SciTech Connect (OSTI)

    Tatarkhanov, Mouslim; Ogletree, D. Frank; Rose, Franck; Mitsui, Toshiyuki; Fomin, Evgeny; Rose, Mark; Cerda, Jorge I.; Salmeron, Miquel

    2009-09-03T23:59:59.000Z

    The initial stages of water adsorption on the Pd(111) and Ru(0001) surfaces have been investigated experimentally by Scanning Tunneling Microscopy in the temperature range between 40 K and 130 K, and theoretically with Density Functional Theory (DFT) total energy calculations and STM image simulations. Below 125 K water dissociation does not occur at any appreciable rate and only molecular films are formed. Film growth starts by the formation of flat hexamer clusters where the molecules bind to the metal substrate through the O-lone pair while making H-bonds with neighboring molecules. As coverage increases, larger networks of linked hexagons are formed with a honeycomb structure, which requires a fraction of the water molecules to have their molecular plane perpendicular to the metal surface with reduced water-metal interaction. Energy minimization favors the growth of networks with limited width. As additional water molecules adsorb on the surface they attach to the periphery of existing islands, where they interact only weakly with the metal substrate. These molecules hop along the periphery of the clusters at intermediate temperatures. At higher temperatures they bind to the metal to continue the honeycomb growth. The water-Ru interaction is significantly stronger than the water-Pd interaction, which is consistent with the greater degree of hydrogen-bonded network formation and reduced water-metal bonding observed on Pd relative to Ru.

  11. Preparation of Ni-Sn alloys by an electroless-deposition method

    SciTech Connect (OSTI)

    Shimauchi, Hidenori; Ozawa, Susumu; Tamura, Keiu; Osaka, Tetsuya (Waseda Univ., Tokyo (Japan). Dept. of Applied Chemistry)

    1994-06-01T23:59:59.000Z

    Ni-Sn alloy is expected for as a functional material, because of its excellent corrosion resistance, wear resistance, and solderability. Electroless-deposited Ni-Sn alloy films were investigated to increase tin content in the deposit. The maximum tin contents of electroless Ni-Sn-P and Ni-Sn-B were ca. 30 atom percent (a/o) and 42 a/o, respectively. The maximum tin contents in the case of Ni-Sn-B was nearly equal to that of electrodeposited Ni-Sn alloy already reported. The crystallinity of Ni-Sn-P and Ni-Sn-B alloys was raised up with an increase in tin content. The corrosion resistance of Ni-Sn-P and Ni-Sn-B alloys was between that of amorphous and crystalline electroless-deposited Ni-P. Codeposition of tin into Ni-P films improved solderability, but into the Ni-B films, the solderability of Ni-Sn-B films situated in the region between those of Ni-P and NiB, because the solderability of NiB is higher.

  12. The first principle study of Ni{sub 2}ScGa and Ni{sub 2}TiGa

    SciTech Connect (OSTI)

    Özduran, Mustafa [Ahi Evran Üniversitesi Fen Edebiyat Fakültesi Fizik Bölümü, K?r?ehir (Turkey); Turgut, Kemal [Yüksek Lisans Ö?rencisi, K?r?ehir (Turkey); Arikan, Nihat [Ahi Evran Üniversitesi E?itim Fakültesi ?lkö?retim Bölümü, K?r?ehir (Turkey); ?yigör, Ahmet; Candan, Abdullah [Ahi Evran Üniversitesi Merkezi Ara?t?rma Laboratuvar?, K?r?ehir (Turkey)

    2014-10-06T23:59:59.000Z

    We computed the electronic structure, elastic moduli, vibrational properties, and Ni{sub 2}TiGa and Ni{sub 2}ScGa alloys in the cubic L2{sub 1} structure. The obtained equilibrium lattice constants of these alloys are in good agreement with available data. In cubic systems, there are three independent elastic constants, namely C{sub 11}, C{sub 12} and C{sub 44}. We calculated elastic constants in L2{sub 1} structure for Ni{sub 2}TiGa and Ni{sub 2}ScGa using the energy-strain method. The electronic band structure, total and partial density of states for these alloys were investigated within density functional theory using the plane-wave pseudopotential method implemented in Quantum-Espresso program package. From band structure, total and projected density of states, we observed metallic characters of these compounds. The electronic calculation indicate that the predominant contributions of the density of states at Fermi level come from the Ni 3d states and Sc 3d states for Ni{sub 2}TiGa, Ni 3d states and Sc 3d states for Ni{sub 2}ScGa. The computed density of states at Fermi energy are 2.22 states/eV Cell for Ni{sub 2}TiGa, 0.76 states/eV Cell for Ni{sub 2}ScGa. The vibrational properties were obtained using a linear response in the framework at the density functional perturbation theory. For the alloys, the results show that the L2{sub 1} phase is unstable since the phonon calculations have imagine modes.

  13. Ni/metal hydride secondary element

    DOE Patents [OSTI]

    Bauerlein, Peter

    2005-04-19T23:59:59.000Z

    A Ni/metal hydride secondary element having a positive nickel hydroxide electrode, a negative electrode having a hydrogen storage alloy, and an alkaline electrolyte, the positive electrode, provided with a three-dimensional metallic conductive structure, also contains an aluminum compound which is soluble in the electrolyte, in addition to nickel hydroxide and cobalt oxide. The aluminum compound is aluminum hydroxide and/or aluminum oxide, and the mass of the aluminum compound which is present in the positive bulk material mixture is 0.1 to 2% by weight relative to the mass of the nickel hydroxide which is present. In combination with aluminum hydroxide or aluminum oxide, the positive electrode further contains lanthanoid oxidic compounds Y.sub.2 O.sub.3, La.sub.2 O.sub.3 and Ca(OH).sub.2, as well as mixtures of these compounds.

  14. Pd Diffusion on MgO(100): The Role of Defects and Small Cluster Mobilit.

    SciTech Connect (OSTI)

    Xu, Lijun; Henkelman, Graeme A.; Campbell, Charles T.; Jonsson, Hannes

    2006-02-09T23:59:59.000Z

    The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. Density functional theory is used to explore the energy landscape of Pd atoms adsorbed on the terrace of MgO(10 0) and at oxygen vacancy sites. Saddle point finding methods reveal that small Pd clusters diffuse on the terrace in interesting ways. The monomer and dimer diffuse via single atom hops between oxygen sites with barriers of 0.34 eV and 0.43 eV respectively. The trimer and tetramer, however, form 3D clusters by overcoming a 2D–3D transition barrier of less than 60 meV. The trimer diffuses along the surface either by a walking or flipping motion, with comparable barriers of ca. 0.5 eV. The tetramer rolls along the terrace with a lower barrier of 0.42 eV. Soft rotational modes at the saddle point lead to an anomalously high prefactor of 1.3 · 1014 s!1 for tetramer diffusion. This prefactor is two order of magnitude higher than for monomer diffusion, making the tetramer the fastest diffusing species on the terrace at all temperatures for which diffusion is active (above 200 K). Neutral oxygen vacancy sites are found to bind Pd monomers with a 2.63 eV stronger binding energy than the terrace. A second Pd atom, however, binds to this trapped monomer with a smaller energy of 0.56 eV, so that dimers at defects dissociate on a time scale of milliseconds at room temperature. Larger clusters bind more strongly at defects. Trimers and tetramers dissociate from monomer-bound-defects at elevated temperatures of ca. 600 K. These species are also mobile on the terrace, suggesting they are important for the ripening observed at P600 K during Pd vapor deposition on MgO(100) by Haas et al. [G. Haas, A. Menck, H. Brune, J.V. Barth, J.A. Venables, K. Kern, Phys. Rev. B 61 (2000) 11105].

  15. Reaction synthesis of Ni-Al based particle composite coatings

    SciTech Connect (OSTI)

    SUSAN,DONALD F.; MISIOLEK,WOICECK Z.; MARDER,ARNOLD R.

    2000-02-11T23:59:59.000Z

    Electrodeposited metal matrix/metal particle composite (EMMC) coatings were produced with a nickel matrix and aluminum particles. By optimizing the process parameters, coatings were deposited with 20 volume percent aluminum particles. Coating morphology and composition were characterized using light optical microscopy (LOM), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). Differential thermal analysis (DTA) was employed to study reactive phase formation. The effect of heat treatment on coating phase formation was studied in the temperature range 415 to 1,000 C. Long-time exposure at low temperature results in the formation of several intermetallic phases at the Ni matrix/Al particle interfaces and concentrically around the original Al particles. Upon heating to the 500--600 C range, the aluminum particles react with the nickel matrix to form NiAl islands within the Ni matrix. When exposed to higher temperatures (600--1,000 C), diffusional reaction between NiAl and nickel produces ({gamma})Ni{sub 3}Al. The final equilibrium microstructure consists of blocks of ({gamma}{prime})Ni{sub 3}Al in a {gamma}(Ni) solid solution matrix, with small pores also present. Pore formation is explained based on local density changes during intermetallic phase formation and microstructural development is discussed with reference to reaction synthesis of bulk nickel aluminides.

  16. 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.

  17. EFFECT OF PRETREATMENT ON PT-CO/C CATHODE CATALYSTS FOR THE OXYGEN-REDUCTION REACTION

    SciTech Connect (OSTI)

    Fox, E.

    2009-05-13T23:59:59.000Z

    In order to reduce the precious metal loading without sacrificing activity and stability, a new method for the preparation of bimetallic catalysts is proposed. Currently, Pt-alloy particles, with 2 to 3 nm in diameter, are loaded on high surface area carbon supports. Of the Pt loaded, only the surface atoms interact with the reactants. In order to increase the Pt utilization per metal particle the new process for catalyst preparation will incorporate a non-noble transition metal core coated with a skin layer of Pt deposited on high surface area carbon. The effect of reducing agent strength during synthesis was also explored. It was determined that the Co addition has a higher impact on catalyst when used with NaBH4 as reducing agent as compared to NaCOOH.

  18. 10 CFR Ch. III (1-1-11 Edition) Pt. 851, App. B

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

    10:19 Feb 15, 2011 Jkt 223033 PO 00000 Frm 00632 Fmt 8010 Sfmt 8002 Y:SGML223033.XXX 223033 jdjones on DSK8KYBLC1PROD with CFR 623 Department of Energy Pt. 851, App. B (2)...

  19. Bimagnetic Core/Shell FePt/Fe3O4 Nanoparticles

    E-Print Network [OSTI]

    Wang, Zhong L.

    and H2S.11,12 Procedures leading to novel inorganic core/shell structures with controlled dimensions nanoparticles, FePt and Fe3O4, followed by reduc- tive annealing to remove organic surfactant around each

  20. Excellent Sulfur Resistance of Pt/BaO/CeO2 Lean NOx Trap Catalysts...

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

    and CHF Peden.2008."Excellent Sulfur Resistance of PtBaOCeO2 Lean NOx Trap Catalysts."Applied Catalysis. B, Environmental 84(3-4):545-551. doi:10.1016j.apcatb.2008.05.009...

  1. ** ALL CHARGES ARE PER SEMESTER UNLESS OTHERWISE NOTED** Dental Hygiene FT Dental Hygiene PT

    E-Print Network [OSTI]

    Weber, David J.

    ** ALL CHARGES ARE PER SEMESTER UNLESS OTHERWISE NOTED** Dental Hygiene FT Dental Hygiene PT (Less Lease 266.00 266.00 SADHA Membership Fee - Fall 65.00 65.00 Dental Hygiene Pins - Fall - 2nd Year 70

  2. ** ALL CHARGES ARE PER SEMESTER UNLESS OTHERWISE NOTED** Dental Hygiene FT Dental Hygiene PT

    E-Print Network [OSTI]

    Weber, David J.

    ** ALL CHARGES ARE PER SEMESTER UNLESS OTHERWISE NOTED** Dental Hygiene FT Dental Hygiene PT (Less Fee - Fall 65.00 65.00 Dental Hygiene Pins - Fall - 2nd Year 70.00 70.00 Disability Insurance: 10

  3. Electric field control of domain wall propagation in Pt/Co/GdOx films

    E-Print Network [OSTI]

    Bauer, Uwe

    The influence of a gate voltage on domain wall (DW) propagation is investigated in ultrathin Pt/Co/gadolinium oxide (GdOx) films with perpendicular magnetic anisotropy. The DW propagation field can be enhanced or retarded ...

  4. PROCESS PARAMETERS for INFRARED PROCESSING of FePt NANOPARTICLE FILMS

    SciTech Connect (OSTI)

    Sabau, Adrian S [ORNL; Kadolkar, Puja [ORNL; Dinwiddie, Ralph Barton [ORNL; Ott, Ronald D [ORNL; Blue, Craig A [ORNL

    2007-01-01T23:59:59.000Z

    Pulse thermal processing (PTP) of FePt nanoparticle films was studied using a high density infrared (HDI) plasma arc lamp. FePt nanoparticle films on silicon substrates were processed using 0.25- second infrared (IR) pulses. The processing was aimed at reaching a peak target temperature for multiple pulses of 550 C. Numerical simulations of the heat transfer for the PTP were performed to determine the operating power levels for the plasma arc lamp. Infrared measurements were conducted to obtain experimental data for the surface temperature of the FePt nanofilm. Parameters needed for the heat-transfer model were identified based on the experimental temperature results. Following the model validation, several numerical simulations were performed to estimate the power levels. It was shown that the FePt nanoparticle films were successfully processed using the power levels provided by the heat-transfer analysis.

  5. Fractional factorial study of HCN removal over a 0.5% Pt/AlO...

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

    PtAlO catalyst: effects of temperature, gas flow rate, and reactant Abstract: Fractional factorial design was used to determine which factors have significant effects on the HCN...

  6. Unconventional behavior of the Ce3Pt23Si11 ferromagnet C. Opagiste,1,

    E-Print Network [OSTI]

    Boyer, Edmond

    23Si11 is in equilibrium with the non-centrosymetric heavy fermion superconductor CePt3Si, when and presents a heavy fermion supercon- ducting state at Tc = 750 mK. Many studies on the superconductivity

  7. Interfacial current-induced torques in Pt/Co/GdOx

    E-Print Network [OSTI]

    Emori, Satoru

    Current-driven domain wall (DW) motion is investigated in Pt/Co/GdOx nanostrips with perpendicular magnetic anisotropy. Measurements of the propagation field and the energy barrier for thermally activated DW motion reveal ...

  8. Chemo-sensors development based on low-dimensional codoped Mn2O3-ZnO nanoparticles using flat-silver electrodes

    E-Print Network [OSTI]

    Rahman, Mohammed M; Gruner, George; Al-Ghamdi, Mohammed Saad; Daous, Muhammed A; Khan, Sher Bahadar; Asiri, Abdullah M

    2013-01-01T23:59:59.000Z

    sensor based on a Pd-Ni/SiNWs electrode. Sens Actuator Bsensor based on a Pd-Ni/SiNWs electrode. App Surf Sci 2009,

  9. Graphene Monolayer Rotation on Ni(111) Facilities Bilayer Graphene Growth

    SciTech Connect (OSTI)

    Batzill M.; Sutter P.; Dahal, A.; Addou, R.

    2012-06-11T23:59:59.000Z

    Synthesis of bilayer graphene by chemical vapor deposition is of importance for graphene-based field effect devices. Here, we demonstrate that bilayer graphene preferentially grows by carbon-segregation under graphene sheets that are rotated relative to a Ni(111) substrate. Rotated graphene monolayer films can be synthesized at growth temperatures above 650 C on a Ni(111) thin-film. The segregated second graphene layer is in registry with the Ni(111) substrate and this suppresses further C-segregation, effectively self-limiting graphene formation to two layers.

  10. Nondestructive evaluation of Ni-Ti shape memory alloy

    SciTech Connect (OSTI)

    Meir, S.; Gordon, S.; Karsh, M.; Ayers, R.; Olson, D. L. [Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, CO (United States); Wiezman, A. [Netania (Israel)

    2011-06-23T23:59:59.000Z

    The nondestructive evaluation of nickel titanium (Ni-Ti) alloys for applications such as heat treatment for biomaterials applications (dental) and welding was investigated. Ni-Ti alloys and its ternary alloys are valued for mechanical properties in addition to the shape memory effect. Two analytical approaches were perused in this work. Assessment of the microstructure of the alloy that determines the martensitic start temperature (Ms) of Ni-Ti alloy as a function of heat treatment, and secondly, an attempt to evaluate a Friction Stir Welding, which involves thermo-mechanical processing of the alloy.

  11. Minority anion substitution by Ni in ZnO

    E-Print Network [OSTI]

    Pereira, Lino Miguel da Costa; Correia, João Guilherme; Amorim, Lígia Marina; Silva, Daniel José; David-Bosne, Eric; Decoster, Stefan; da Silva, Manuel Ribeiro; Temst, Kristiaan; Vantomme, André

    2013-01-01T23:59:59.000Z

    We report on the lattice location of implanted Ni in ZnO using the $\\beta$? emission channeling technique. In addition to the majority substituting for the cation (Zn), a significant fraction of the Ni atoms occupy anion (O) sites. Since Ni is chemically more similar to Zn than it is to O, the observed O substitution is rather puzzling. We discuss these findings with respect to the general understanding of lattice location of dopants in compound semiconductors. In particular, we discuss potential implications on the magnetic behavior of transition metal doped dilute magnetic semiconductors.

  12. Synthesis of Pt nanoparticles on electrochemically reduced graphene oxide by potentiostatic and alternate current methods

    SciTech Connect (OSTI)

    Molina, J.; Fernández, J.; Río, A.I. del; Bonastre, J.; Cases, F., E-mail: fjcases@txp.upv.es

    2014-03-01T23:59:59.000Z

    Reduced graphene oxide (RGO) has been synthesized on Pt wires by means of a potentiodynamic method between + 0.6 V and ? 1.4 V for 20 scans. Cyclic voltammetry characterization of the coatings showed the typical capacitative behavior of graphene. Pt nanoparticles were synthesized on Pt–RGO electrodes by means of potentiostatic methods and a comparison between different synthesis potentials (? 0.16, 0, + 0.2 and + 0.4 V) for the same synthesis charge (mC·cm{sup ?2}) was established. The electrodes obtained were characterized in 0.5 M H{sub 2}SO{sub 4} solution to observe the characteristic oxidation and reduction processes of the Pt surface. A 0.5 M H{sub 2}SO{sub 4}/0.5 M CH{sub 3}OH solution was used to measure the catalytic properties of the deposits against methanol oxidation. The most appropriate potential to perform the synthesis was 0 V followed by ? 0.16 V and + 0.2 V. The morphology of the coatings varied depending on the potential applied as observed by scanning electron microscopy. Alternate current methods were also used to synthesize Pt nanoparticles and compare the results with the traditional potentiostatic method. Different frequencies were used: 0.1, 1, 10, 100, 1000 and 10 000 Hz. Alternate current synthesis is more efficient than traditional potentiostatic methods, obtaining more electroactive coatings with less effective synthesis time. - Highlights: • Reduced graphene oxide has been obtained by electrochemical reduction on Pt wires. • Pt nanoparticles have been obtained potentiostatically at different potentials. • Pt nanoparticles have been obtained by ac methods with different frequencies. • ac synthesis is a better synthesis method than potentiostatic synthesis.

  13. Spectral Singularity in confined PT symmetric optical potential

    E-Print Network [OSTI]

    Anjana Sinha; R. Roychoudhury

    2013-11-13T23:59:59.000Z

    We present an analytical study for the scattering amplitudes (Reflection $|R|$ and Transmission $|T|$), of the periodic ${\\cal{PT}}$ symmetric optical potential $ V(x) = \\displaystyle W_0 \\left( \\cos ^2 x + i V_0 \\sin 2x \\right) $ confined within the region $0 \\leq x \\leq L$, embedded in a homogeneous medium having uniform potential $W_0$. The confining length $L$ is considered to be some integral multiple of the period $ \\pi $. We give some new and interesting results. Scattering is observed to be normal ($|T| ^2 \\leq 1, \\ |R|^2 \\leq 1$) for $V_0 \\leq 0.5 $, when the above potential can be mapped to a Hermitian potential by a similarity transformation. Beyond this point ($ V_0 > 0.5 $) scattering is found to be anomalous ($|T| ^2, \\ |R|^2 $ not necessarily $ \\leq 1 $). Additionally, in this parameter regime of $V_0$, one observes infinite number of spectral singularities $E_{SS}$ at different values of $V_0$. Furthermore, for $L= 2 n \\pi$, the transition point $V_0 = 0.5$ shows unidirectional invisibility with zero reflection when the beam is incident from the absorptive side ($Im [V(x)] 0$), transmission being identically unity in both cases. Finally, the scattering coefficients $|R|^2$ and $|T|^2 $ always obey the generalized unitarity relation : $ ||T|^2 - 1| = \\sqrt{|R_R|^2 |R_L|^2}$, where subscripts $R$ and $L$ stand for right and left incidence respectively.

  14. Excess Ni-doping induced enhanced room temperature magneto-functionality in Ni-Mn-Sn based shape memory alloy

    SciTech Connect (OSTI)

    Pramanick, S.; Giri, S.; Majumdar, S., E-mail: sspsm2@iacs.res.in [Department of Solid State Physics, Indian Association for the Cultivation of Science, 2A and B Raja S. C. Mullick Road, Jadavpur, Kolkata 700 032 (India); Chatterjee, S. [UGC-DAE Consortium for Scientific Research, Kolkata Centre, Sector III, LB-8, Salt Lake, Kolkata 700 098 (India)

    2014-09-15T23:59:59.000Z

    Present work reports on the observation of large magnetoresistance (??30% at 80 kOe) and magnetocaloric effect (?12?J·kg{sup ?1}·K{sup ?1} for 0–50 kOe) near room temperature (?290?K) on the Ni-excess ferromagnetic shape memory alloy Ni{sub 2.04}Mn{sub 1.4}Sn{sub 0.56}. The sample can be thought of being derived from the parent Ni{sub 2}Mn{sub 1.4}Sn{sub 0.6} alloy, where excess Ni was doped at the expense of Sn. Such Ni doping enhances the martensitic transition temperature and for the Ni{sub 2.04}Mn{sub 1.4}Sn{sub 0.56} it is found to be optimum (288?K). The doped alloy shows enhanced magneto-functional properties as well as reduced saturation magnetization as compared to the undoped counterpart at low temperature. A probable increment of antiferromagnetic correlation between Mn-atoms on Ni substitution can be accounted for the enhanced magneto-functional properties as well as reduction in saturation moment.

  15. 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.

  16. TiNi shape memory alloy thin films for microactuator application

    E-Print Network [OSTI]

    Fu, Yongqing

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

  17. Perpendicular magnetic anisotropy in ion beam sputtered Co/Ni multilayers

    E-Print Network [OSTI]

    Rasin, Boris

    2009-01-01T23:59:59.000Z

    Co/Ni multilayers display perpendicular magnetic anisotropy and have applications in magnetic devices that could lead to a large increase in the density of magnetic storage. Co/Ni 10-(2 Å Co/ 8Å Ni) and 10-(2 Å Co/ 4 Å Ni) ...

  18. TUNING OF SIZE AND SHAPE OF AU-PT NANOCATALYST FOR DIRECT METHANOL FUEL CELLS

    SciTech Connect (OSTI)

    Murph, S.

    2011-04-20T23:59:59.000Z

    In this paper, we report the precise control of the size, shape and surface morphology of Au-Pt nanocatalysts (cubes, blocks, octahedrons and dogbones) synthesized via a seed-mediated approach. Gold 'seeds' of different aspect ratios (1 to 4.2), grown by a silver-assisted approach, were used as templates for high-yield production of novel Au-Pt nanocatalysts at a low temperature (40 C). Characterization by electron microscopy (SEM, TEM, HRTEM), energy dispersive X-ray analysis (EDX), UV-Vis spectroscopy, zeta-potential (surface charge), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma mass spectrometry (ICP-MS) were used to better understand their physico-chemical properties, preferred reactivities and underlying nanoparticle growth mechanism. A rotating disk electrode was used to evaluate the Au-Pt nanocatalysts electrochemical performance in the oxygen reduction reaction (ORR) and the methanol oxidation reaction (MOR) of direct methanol fuel cells. The results indicate the Au-Pt dogbones are partially and in some cases completely unaffected by methanol poisoning during the evaluation of the ORR. The ORR performance of the octahedron particles in the absence of MeOH is superior to that of the Au-Pt dogbones and Pt-black, however its performance is affected by the presence of MeOH.

  19. Synthesis, Characterization, and Catalytic Oxygen Electroreduction Activities of Carbon-Supported PtW Nanoparticle Catalysts

    SciTech Connect (OSTI)

    Xiong, Liufeng [Honda Research Institute; More, Karren Leslie [ORNL; He, Ting [Honda Research Institute

    2010-01-01T23:59:59.000Z

    Carbon-supported PtW (PtW/C) alloy nanoparticle catalysts with well-controlled particle size, dispersion, and composition uniformity, have been synthesized by wet chemical methods of decomposition of carbonyl cluster complexes, hydrolysis of metal salts, and chemical reactions within a reverse microemulsion. The synthesized PtW/C catalysts were characterized by X-ray diffraction, high-resolution transmission electron microscopy, and energy-dispersive spectroscopy. The catalytic oxygen electroreduction activities were measured by the hydrodynamic rotating disk electrode technique in an acidic electrolyte. The influence of the synthesis method on PtW particle size, size distribution, composition uniformity, and catalytic oxygen electroreduction activity, have been investigated. Among the synthesis methods studied, PtW/C catalysts prepared by the decomposition of carbonyl cluster complexes displayed the best platinum mass activity for oxygen reduction reaction under the current small scale production; a 3.4-fold catalytic enhancement was achieved in comparison to a benchmark Pt/C standard.

  20. Highly Stable and Active Pt-Cu Oxygen Reduction Electrocatalysts Based on Mesoporous Graphitic Carbon Supports

    SciTech Connect (OSTI)

    Dai, Sheng [ORNL; Gupta, Gaurav [University of Texas, Austin; Kumar, Pavan [University of Texas, Austin; Wiggins-camacho, Jaclyn [University of Texas, Austin; Wang, Xiqing [ORNL; Swinnea, Steven [University of Texas, Austin; More, Karren Leslie [ORNL; Stevenson, Keith J [ORNL; Johnston, Keith [University of Texas, Austin

    2009-01-01T23:59:59.000Z

    The activity of oxygen reduction catalysts for fuel cells often decreases markedly (30-70%) during potential cycling tests designed to accelerate catalyst degradation. Herein we achieved essentially no loss in electrochemical surface area and catalyst activity during potential cycling from 0.5 to 1.2 V for presynthesized Pt-Cu nanoparticles of controlled composition that were infused into highly graphitic disordered mesoporous carbons (DMC). The high stability is favored by the strong metal-support interactions and low tendency for carbon oxidation, which mitigates the mechanisms of degradation. Electrochemical dealloying transforms the composition from Pt{sub 20}Cu{sub 80} to Pt{sub 85}Cu{sub 15} with a strained Pt-rich shell, which exhibits an enhanced ORR activity of 0.46 A/mg{sub Pt}, >4 fold that of pure Pt catalysts. The high uniformity in particle size and composition both before and after dealloying, as a consequence of the presynthesis/infusion technique, is beneficial for elucidating the mechanism of catalyst activity and, ultimately, for designing more active catalysts.

  1. Site selective substitution Pt for Ti in KTiOPO{sub 4}:Ga crystals revealed by electron paramagnetic resonance

    SciTech Connect (OSTI)

    Grachev, V.; Meyer, M.; Jorgensen, J.; Malovichko, G. [Department of Physics, Montana State University, Bozeman, Montana 59717 (United States); Hunt, A. W. [Idaho Accelerator Center, Idaho State University, Pocatello, Idaho 83209 (United States)

    2014-07-28T23:59:59.000Z

    Electron Paramagnetic Resonance at low temperatures has been used to characterize potassium titanyl phosphate (KTiOPO{sub 4}) single crystals grown by different techniques. Irradiation with 20?MeV electrons performed at room temperature and liquid nitrogen temperature caused an appearance of electrons and holes. Platinum impurities act as electron traps in KTiOPO{sub 4} creating Pt{sup 3+} centers. Two different Pt{sup 3+} centers were observed, Pt(A) and Pt(D). The Pt(A) centers are dominant in undoped samples, whereas Pt(D)—in Ga-doped KTP crystals. Superhyperfine structure registered for Pt(D) centers was attributed to interactions of platinum electrons with {sup 39}K and two {sup 31}P nuclei in their surroundings. In both Pt(A) and Pt(D) centers, Pt{sup 3+} ions substitute for Ti{sup 4+} ions, but with a preference to one of two electrically distinct crystallographic positions. The site selective substitution can be controlled by the Ga-doping.

  2. Ni(NiO)/single-walled carbon nanotubes composite: Synthesis of electro-deposition, gas sensing property for NO gas and density functional theory calculation

    SciTech Connect (OSTI)

    Li, Li; Zhang, Guo; Chen, Lei [Key Laboratory of Chemical Engineering Process and Technology for High-efficiency Conversion, College of Heilongjiang Province, Heilongjiang University, Harbin 150080 (China)] [Key Laboratory of Chemical Engineering Process and Technology for High-efficiency Conversion, College of Heilongjiang Province, Heilongjiang University, Harbin 150080 (China); Bi, Hong-Mei [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China)] [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China); Shi, Ke-Ying, E-mail: shikeying2008@yahoo.cn [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China)] [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China)

    2013-02-15T23:59:59.000Z

    Graphical abstract: The Ni(NiO)/semiconducting single-walled carbon nanotubes composite collected from the cathode after electro-deposition shows a high sensitivity to low-concentration NO gas at room temperature (18 °C). Display Omitted Highlights: ? Ni(NiO) nanoparticles were deposited on semiconducting SWCNTs by electro-deposition. ? Ni(NiO)/semiconducting SWCNTs film shows a high sensitivity to NO gas at 18 °C. ?Theoretical calculation reveals electron transfer from SWCNTs to NO via Ni. -- Abstract: Single-walled carbon nanotubes which contains metallic SWCNTs (m-SWCNTs) and semiconducting SWCNTs (s-SWCNTs) have been obtained under electric arc discharge. Their separation can be effectively achieved by the electro-deposition method. The Ni(NiO)/s-SWCNTs composite was found on cathode where Ni was partially oxidized to NiO at ambient condition with Ni(NiO) nanoparticles deposited uniformly on the bundles of SWCNTs. These results were confirmed by Raman spectra, transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV–vis–NIR and TG characterizations. Furthermore, investigation of the gas sensing property of Ni(NiO)/s-SWCNTs composite film to NO gas at 18 °C demonstrated the sensitivity was approximately 5% at the concentration of 97 ppb. Moreover, density functional theory (DFT) calculations were performed to explore the sensing mechanism which suggested the adsorption of NO molecules onto the composite through N–Ni interaction as well as the proposition of electron transfer mechanisms from SWCNTs to NO via the Ni medium.

  3. $^{64}$Ni+$^{64}$Ni fusion reaction calculated with the density-constrained time-dependent Hartree-Fock formalism

    E-Print Network [OSTI]

    A. S. Umar; V. E. Oberacker

    2007-09-25T23:59:59.000Z

    We study fusion reactions of the $^{64}$Ni+$^{64}$Ni system using the density-constrained time-dependent Hartree-Fock (TDHF) formalism. In this formalism the fusion barriers are directly obtained from TDHF dynamics. In addition, we incorporate the entrance channel alignments of the slightly deformed (oblate) $^{64}$Ni nuclei due to dynamical Coulomb excitation. We show that alignment leads to a fusion barrier distribution and alters the naive picture for defining which energies are actually sub-barrier. We also show that core polarization effects could play a significant role in fusion cross section calculations.

  4. Electronic structure of the 4d transition metal carbides: Dispersed fluorescence spectroscopy of MoC, RuC, and PdC

    E-Print Network [OSTI]

    Morse, Michael D.

    C, RuC, and PdC Ryan S. DaBell,a) Raymond G. Meyer,b) and Michael D. Morsec) Department of Chemistry fluorescence studies of the diatomic molecules MoC, RuC, and PdC are reported. New states identified in Mo are observed by dispersed fluorescence in PdC. The ground state is found to be ... 2 4 12 2 , 1

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

    E-Print Network [OSTI]

    Simon, Jesse Matthew

    2007-01-01T23:59:59.000Z

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

  6. Focus Article El Ni ~no and our future climate

    E-Print Network [OSTI]

    Wittenberg, Andrew

    Focus Article El Ni ~no and our future climate: where do we stand? Gabriel A. Vecchi and Andrew T activity, including a decrease in Atlantic hurricane activity6 and an eastward shift of western Pacific

  7. Grain boundary relaxation strengthening of nanocrystalline Ni–W alloys

    E-Print Network [OSTI]

    Rupert, Timothy J.

    The hardening effect caused by the relaxation of nonequilibrium grain boundary structure has been explored in nanocrystalline Ni–W alloys. First, the kinetics of relaxation hardening are studied, showing that higher annealing ...

  8. Mechanical Behavior of Cryomilled Ni Superalloy by Spark Plasma Sintering

    E-Print Network [OSTI]

    2009-01-01T23:59:59.000Z

    Ni Superalloy by Spark Plasma Sintering Z. ZHANG, B.Q. HAN,cryomilling and spark plasma sintering (SPS) was studied.prepared by the spark plasma sintering (SPS) technique. To

  9. TiNi-based thin films for MEMS applications

    E-Print Network [OSTI]

    Fu, Yongqing

    In this paper, some critical issues and problems in the development of TiNi thin films were discussed, including preparation and characterization considerations, residual stress and adhesion, frequency improvement, fatigue ...

  10. The stellar (n,gamma) cross section of 62Ni

    E-Print Network [OSTI]

    H. Nassar; M. Paul; I. Ahmad; D. Berkovits; M. Bettan; P. Collon; S. Dababneh; S. Ghelberg; J. P. Greene; A. Heger; M. Heil; D. J. Henderson; C. L. Jiang; F. Kaeppeler; H. Koivisto; S. O'Brien; R. C. Pardo; N. Patronis; T. Pennington; R. Plag; K. E. Rehm; R. Reifarth; R. Scott; S. Sinha; X. Tang; R. Vondrasek

    2005-03-12T23:59:59.000Z

    The 62Ni(n,gamma)63Ni(t_1/2=100+-2 yrs) reaction plays an important role in the control of the flow path of the slow neutron-capture (s-) nucleosynthesis process. We have measured for the first time the total cross section of this reaction for a quasi-Maxwellian (kT = 25 keV) neutron flux. The measurement was performed by fast-neutron activation, combined with accelerator mass spectrometry to detect directly the 63Ni product nuclei. The experimental value of 28.4+-2.8 mb, fairly consistent with a recent theoretical estimate, affects the calculated net yield of 62Ni itself and the whole distribution of nuclei with 62

  11. Electrodeposition of amorphous matrix Ni-W/Wp̳ composites

    E-Print Network [OSTI]

    Jenket, Donald R. (Donald Robert)

    2005-01-01T23:59:59.000Z

    An amorphous Ni-W alloy matrix was incorporated with W particulate through two types of electrodeposition. The plating bath for the electrodeposition contained nickel sulfate, sodium tungstate, sodium citrate, ammonium ...

  12. Double dumbbell shaped AgNi alloy by pulsed electrodeposition

    SciTech Connect (OSTI)

    Dhanapal, K.; Vasumathi, M.; Santhi, Kalavathy [Materials Science Centre, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai 600 025 (India); Narayanan, V., E-mail: stephen-arum@hotmail.com; Stephen, A., E-mail: stephen-arum@hotmail.com [Department of Inorganic Chemistry, University of Madras, Guindy Campus, Chennai-600 025 (India)

    2014-01-28T23:59:59.000Z

    Silver-Nickel is the well-known thermally immiscible system that makes them quite complex for the formation of alloy. This kind of alloy can be attained from electrodeposition method. In the present work, AgNi alloy was synthesized by pulsed electrodeposition in a single bath two electrode system with the use of anodic alumina membrane. The prepared AgNi alloy and pure Ag were characterized with X-ray Diffraction (XRD) for structural confirmation, Scanning Electron Microscopy (SEM) for morphological, and magnetic properties by Vibrating Sample Magnetometer, respectively. The X-ray Diffraction study shows the formation of cubic structure for pure Ag. SEM analysis reveals the double dumbbell morphology for AgNi alloy and spherically agglomeration for pure silver. Hysteresis behaviour from VSM measurement indicates that the AgNi alloy have good ferro-magnetic properties.

  13. {sup 103}Pd strings: Monte Carlo assessment of a new approach to brachytherapy source design

    SciTech Connect (OSTI)

    Rivard, Mark J., E-mail: mark.j.rivard@gmail.com [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States); Reed, Joshua L.; DeWerd, Larry A. [Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States)] [Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States)

    2014-01-15T23:59:59.000Z

    Purpose: A new type of{sup 103}Pd source (CivaString and CivaThin by CivaTech Oncology, Inc.) is examined. The source contains {sup 103}Pd and Au radio-opaque marker(s), all contained within low-Z{sub eff} organic polymers that permit source flexibility. The CivaString source is available in lengths L of 10, 20, 30, 40, 50, and 60 mm, and referred to in the current study as CS10–CS60, respectively. A thinner design, CivaThin, has sources designated as CT10–CT60, respectively. The CivaString and CivaThin sources are 0.85 and 0.60 mm in diameter, respectively. The source design is novel and offers an opportunity to examine its interesting dosimetric properties in comparison to conventional {sup 103}Pd seeds. Methods: The MCNP5 radiation transport code was used to estimate air-kerma rate and dose rate distributions with polar and cylindrical coordinate systems. Doses in water and prostate tissue phantoms were compared to determine differences between the TG-43 formalism and realistic clinical circumstances. The influence of Ti encapsulation and 2.7 keV photons was examined. The accuracy of superposition of dose distributions from shorter sources to create longer source dose distributions was also assessed. Results: The normalized air-kerma rate was not highly dependent onL or the polar angle ?, with results being nearly identical between the CivaString and CivaThin sources for common L. The air-kerma strength was also weakly dependent on L. The uncertainty analysis established a standard uncertainty of 1.3% for the dose-rate constant ?, where the largest contributors were ?{sub en}/? and ?/?. The ? values decreased with increasing L, which was largely explained by differences in solid angle. The radial dose function did not substantially vary among the CivaString and CivaThin sources for r ? 1 cm. However, behavior for r < 1 cm indicated that the Au marker(s) shielded radiation for the sources having L = 10, 30, and 50 mm. The 2D anisotropy function exhibited peaks and valleys that corresponded to positions adjacent to {sup 103}Pd wells and Au markers, respectively. Dose distributions of both source types had minimal anisotropy in comparison to conventional {sup 103}Pd seeds. Contributions by 2.7 keV photons comprised ?0.1% of the dose from all photons at positions farther than 0.13 mm from the polymer source surface. Differences between absorbed dose to water and prostate became more substantial as distance from the sources increased, with prostate dose being about 13% lower for r = 5 cm. Using a cylindrical coordinate system, dose superposition of small length sources to replicate the dose distribution for a long length source proved to be a robust technique; a 2.0% tolerance compared with the reference dose distribution did not exceed 0.1 cm{sup 3} for any of the examined source combinations. Conclusions: By design, the CivaString and CivaThin sources have novel dosimetric characteristics in comparison to Ti-encapsulated{sup 103}Pd seeds. The dosimetric characterization has determined the reasons for these differences through analysis using Monte Carlo-based radiation transport simulations.

  14. The influence of nano-architectured CeOx supports in RhPd/CeO? for the catalytic ethanol steam reforming reaction

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

    Divins, N. J.; Senanayake, S. D.; Casanovas, A.; Xu, W.; Trovarelli, A.; Llorca, J.

    2015-09-01T23:59:59.000Z

    The ethanol steam reforming (ESR) reaction has been tested over RhPd supported on polycrystalline ceria in comparison to structured supports composed of nanoshaped CeO? cubes and CeO? rods tailored towards the production of hydrogen. At 650-700 K the hydrogen yield follows the trend RhPd/CeO?-cubes > RhPd/CeO? -rods > RhPd/CeO?- polycrystalline, whereas at temperatures higher than 800 K the catalytic performance of all samples is similar and close to the thermodynamic equilibrium. The improved performance of RhPd/CeO?-cubes and RhPd/CeO? -rods for ESR at low temperature is mainly ascribed to higher water-gas shift activity and a strong interaction between the bimetallic -more »oxide support interaction. STEM analysis shows the existence of RhPd alloyed nanoparticles in all samples, with no apparent relationship between ESR performance and RhPd particle size. X-ray diffraction under operating conditions shows metal reorganization on {100} and {110} ceria crystallographic planes during catalyst activation and ESR, but not on {111} ceria crystallographic planes. The RhPd reconstructing and tuned activation over ceria nanocubes and nanorods is considered the main reason for better catalytic activity with respect to conventional catalysts based on polycrystalline ceria« less

  15. Oxygen-related dielectric relaxation and leakage characteristics of Pt,,Ba,Sr...TiO3 Pt thin-film capacitors

    E-Print Network [OSTI]

    Cao, Wenwu

    Oxygen-related dielectric relaxation and leakage characteristics of PtÕ,,Ba,Sr...TiO3 ÕPt thin to the postannealing temperature in oxygen and nitrogen atmosphere. High leakage currents and low-frequency dielectric and subsequently annealed in oxygen at 350 °C. Such results are related to the mobile oxygen ions and oxygen

  16. The Role of Partial Crystallinity on Hydrogen Permeation in Fe–Ni–B–Mo Based Metallic Glass Membranes

    SciTech Connect (OSTI)

    Brinkman, K.; Su, D.; Fox, E.; Korinko, P.; Missimer, D.; Adams, T.

    2011-08-15T23:59:59.000Z

    A potentially exciting material for membrane separations are metallic glass materials due to their low cost, high elastic toughness and resistance to hydrogen embrittlement as compared to crystalline Pd-based membrane systems. However, at elevated temperatures and extended operation times structural changes including partial crystallinity may appear in these amorphous metallic systems. This study reports on the investigation of time and temperature dependent crystalline phase formation in conjunction with in situ crystallization/hydrogen permeation experiments at elevated temperatures. At temperatures near 400 C a FeNi crystalline phase appears as 22 vol.% inside the host amorphous matrix and the resulting composite structure remains stable over 3 h at temperature. The hydrogen permeation at 400 C of the partially crystalline material is similar to the fully amorphous material near 5 x 10{sup -9} mol H{sub 2}/m s Pa{sup 1/2}, while ambient temperature electrochemical permeation at 25 C revealed an order of magnitude decrease in the permeation of partially crystalline materials due to differences in the amorphous versus crystalline phase activation energy for hydrogen permeation.

  17. Spectral singularity in confined PT symmetric optical potential

    SciTech Connect (OSTI)

    Sinha, Anjana [Department of Instrumentation Science, Jadavpur University, Kolkata - 700 032 (India)] [Department of Instrumentation Science, Jadavpur University, Kolkata - 700 032 (India); Roychoudhury, R. [Department of Mathematics, Bethune College, Kolkata - 700 006, India and Advanced Centre for Nonlinear and Complex Phenomena, 1175 Survey Park, Kolkata - 700075 (India)] [Department of Mathematics, Bethune College, Kolkata - 700 006, India and Advanced Centre for Nonlinear and Complex Phenomena, 1175 Survey Park, Kolkata - 700075 (India)

    2013-11-15T23:59:59.000Z

    We present an analytical study for the scattering amplitudes (Reflection ?R? and Transmission ?T?), of the periodic PT symmetric optical potential V(x)=W{sub 0}cos{sup 2}x+iV{sub 0}sin2x confined within the region 0 ?x?L, embedded in a homogeneous medium having uniform potential W{sub 0}. The confining length L is considered to be some integral multiple of the period ?. We give some new and interesting results. Scattering is observed to be normal (?T?{sup 2}? 1, ?R?{sup 2}? 1) for V{sub 0}? 0.5, when the above potential can be mapped to a Hermitian potential by a similarity transformation. Beyond this point (V{sub 0} > 0.5) scattering is found to be anomalous (?T?{sup 2}, ?R?{sup 2} not necessarily ?1). Additionally, in this parameter regime of V{sub 0}, one observes infinite number of spectral singularities E{sub SS} at different values of V{sub 0}. Furthermore, for L= 2n?, the transition point V{sub 0}= 0.5 shows unidirectional invisibility with zero reflection when the beam is incident from the absorptive side (Im[V(x)] < 0) but with finite reflection when the beam is incident from the emissive side (Im[V(x)] > 0), transmission being identically unity in both cases. Finally, the scattering coefficients ?R?{sup 2} and ?T?{sup 2} always obey the generalized unitarity relation : ?T|{sup 2}?1|=?(|R{sub R}|{sup 2}|R{sub L}|{sup 2}), where subscripts R and L stand for right and left incidence, respectively.

  18. Surface structures of Al-Pd-Mn and Al-Cu-Fe icosahedral quasicrystals

    SciTech Connect (OSTI)

    Shen, Z.

    1999-02-12T23:59:59.000Z

    In this dissertation, the author reports on the surface structure of i-Al-Pd-Mn twofold, threefold, fivefold and i-Al-Cu-Fe fivefold surfaces. The LEED studies indicate the existence of two distinct stages in the regrowth of all four surfaces after Ar{sup +} sputtering. In the first stage, upon annealing at relatively low temperature: 500K--800K (depending on different surfaces), a cubic phase appears. The cubic LEED patterns transform irreversibly to unreconstructed quasicrystalline patterns upon annealing to higher temperatures, indicating that the cubic overlayers are metastable. Based upon the data for three chemically-identical, but symmetrically-inequivalent surfaces, a model is developed for the relation between the cubic overlayers and the quasicrystalline substrate. The model is based upon the related symmetries of cubic close-packed and icosahedral-packed materials. These results may be general among Al-rich, icosahedral materials. STM study of Al-Pd-Mn fivefold surface shows that terrace-step-kink structures start to form on the surface after annealing above 700K. Large, atomic ally-flat terraces were formed after annealing at 900K. Fine structures with fivefold icosahedral symmetry were found on those terraces. Data analysis and comparison of the STM images and structure model of icosahedral Al-Pd-Mn suggest that the fine structures in the STM images may be the pseudo Mackay (PMI) clusters which are the structure units of the structure model. Based upon his results, he can conclude that quasicrystalline structures are the stable structures of quasicrystal surfaces. In other words, quasicrystalline structures extend from the bulk to the surface. As a result of the effort reported in this dissertation, he believes that he has increased his understanding of the surface structure of icosahedral quasicrystals to a new level.

  19. Anomalous magnetic behavior in nanocomposite materials of reduced graphene oxide-Ni/NiFe{sub 2}O{sub 4}

    SciTech Connect (OSTI)

    Kollu, Pratap, E-mail: pk419@cam.ac.uk, E-mail: anirmalagrace@vit.ac.in, E-mail: dhirenb@iitb.ac.in [DST-INSPIRE Faculty, Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076 (India); Prathapani, Sateesh; Varaprasadarao, Eswara K.; Mallick, Sudhanshu; Bahadur, D., E-mail: pk419@cam.ac.uk, E-mail: anirmalagrace@vit.ac.in, E-mail: dhirenb@iitb.ac.in [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076 (India); Santosh, Chella; Grace, Andrews Nirmala, E-mail: pk419@cam.ac.uk, E-mail: anirmalagrace@vit.ac.in, E-mail: dhirenb@iitb.ac.in [Centre for Nanotechnology Research, VIT University, Vellore 632014 (India)

    2014-08-04T23:59:59.000Z

    Magnetic Reduced Graphene Oxide-Nickel/NiFe{sub 2}O{sub 4} (RGO-Ni/NF) nanocomposite has been synthesized by one pot solvothermal method. Respective phase formations and their purities in the composite are confirmed by High Resolution Transmission Electron Microscope and X Ray Diffraction, respectively. For the RGO-Ni/NF composite material finite-size effects lead to the anomalous magnetic behavior, which is corroborated in temperature and field dependent magnetization curves. Here, we are reporting the behavior of higher magnetization values for Zero Field Cooled condition to that of Field Cooled for the RGO-Ni/NF nanocomposite. Also, the observed negative and positive moments in Hysteresis loops at relatively smaller applied fields (100?Oe and 200?Oe) are explained on the basis of surface spin disorder.

  20. Impact of PK/PD, Disease Models and Personalized Medicine to Influence FDA Decisions

    E-Print Network [OSTI]

    Powell, Robert

    2006-10-26T23:59:59.000Z

    Impact of PK/PD, Disease Models and Personalized Medicine to Influence FDA Decisions Bob Powell, Pharm.D. Pharmacometrics Offices of Clinical Pharmacology & Translational Sciences Center for Drug Evaluation & Research FDA robert... 0 2 0 4 0 6 0 8 0 1 0 0 1 2 0 T r o u g h C o n c e n t r a t i o n i n u g / m L Cmin in Phase 2 and Phase 3 at Different Doses 500/200 Study 52 750/200 Study 52 500/200 Study 12/48 TPV Cmin, IC50, T20 co-administration significantly influence...

  1. Travelling fronts of the CO oxidation on Pd(111) with coverage-dependent diffusion

    SciTech Connect (OSTI)

    Cisternas, Jaime, E-mail: jecisternas@miuandes.cl [Facultad de Ingeniería y Ciencias Aplicadas, Universidad de los Andes, Monseñor Alvaro del Portillo 12455, Las Condes, Santiago (Chile); Karpitschka, Stefan [Physics of Fluids, University of Twente, Drienerlolaan 5, 7522 NB Enschede (Netherlands); Wehner, Stefan [Institut für Integrierte Naturwissenschaften - Physik, Universität Koblenz-Landau, 56070 Koblenz (Germany)

    2014-10-28T23:59:59.000Z

    In this work, we study a surface reaction on Pd(111) crystals under ultra-high-vacuum conditions that can be modeled by two coupled reaction-diffusion equations. In the bistable regime, the reaction exhibits travelling fronts that can be observed experimentally using photo electron emission microscopy. The spatial profile of the fronts reveals a coverage-dependent diffusivity for one of the species. We propose a method to solve the nonlinear eigenvalue problem and compute the direction and the speed of the fronts based on a geometrical construction in phase-space. This method successfully captures the dependence of the speed on control parameters and diffusivities.

  2. Structure and phase transformation behaviour of electroless Ni-P composite coatings

    SciTech Connect (OSTI)

    Balaraju, J.N. [Surface Engineering Division, National Aerospace Laboratory, Bangalore 560017 (India)]. E-mail: jnbalraj@css.nal.res.in; Narayanan, T.S.N. Sankara [National Metallurgical Laboratory, Madras Centre, CSIR Complex Taramani, Chennai 600113 (India)]. E-mail: tsnsn@rediffmail.com; Seshadri, S.K. [Department of Metallurgical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India)]. E-mail: sks@iitm.ac.in

    2006-04-13T23:59:59.000Z

    This paper addresses the structural characteristics and phase transformation behaviour of plain electroless Ni-P coating and electroless Ni-P-Si{sub 3}N{sub 4}, Ni-P-CeO{sub 2} and Ni-P-TiO{sub 2} composite coatings. The X-ray diffraction patterns of electroless Ni-P-Si{sub 3}N{sub 4}, Ni-P-CeO{sub 2} and Ni-P-TiO{sub 2} composite coatings are very similar to that of plain electroless Ni-P coating, both in as plated and heat-treated conditions. Selected area electron diffraction (SAED) patterns obtained on the Ni-P matrix of Ni-P-Si{sub 3}N{sub 4}, Ni-P-CeO{sub 2} and Ni-P-TiO{sub 2} composite coatings exhibit diffuse ring patterns resembling the one obtained for plain electroless Ni-P coating. Phase transformation behaviour studied by differential scanning calorimetry (DSC) indicates that the variation in crystallization temperature and the energy evolved during crystallization of plain electroless Ni-P coating and electroless Ni-P-Si{sub 3}N{sub 4}, Ni-P-CeO{sub 2} and Ni-P-TiO{sub 2} composite coatings is not significant. The study concludes that incorporation of Si{sub 3}N{sub 4}, CeO{sub 2} and TiO{sub 2} particles in the Ni-P matrix does not have any influence on the structure and phase transformation behaviour of electroless Ni-P coatings.

  3. Electron Density Distributions Calculated for the Nickel Sulfides Millerite, Vaesite, and Heazlewoodite and Nickel Metal: A Case for the Importance of Ni-Ni Bond Paths for

    E-Print Network [OSTI]

    Downs, Robert T.

    Electron Density Distributions Calculated for the Nickel Sulfides Millerite, Vaesite, and Heazlewoodite and Nickel Metal: A Case for the Importance of Ni-Ni Bond Paths for Electron Transport G. V. Gibbs's)) have been calculated for the bonded interactions comprising the nickel sulfide minerals millerite, Ni

  4. Balance of Nanostructure and Bimetallic Interactions in Pt Model Fuel Cell Catalysts: An in Situ XAS and DFT Study

    SciTech Connect (OSTI)

    Friebel, Daniel; Viswanathan, Venkatasubramanian; Miller, Daniel James; Anniyev, Toyli; Ogasawara, Hirohito; Larsen, Ask Hjorth; O'Grady, Christopher P.; Norskov, Jens K.; Nilsson, Anders

    2012-05-31T23:59:59.000Z

    We have studied the effect of nanostructuring in Pt monolayer model electrocatalysts on a Rh(111) single-crystal substrate on the adsorption strength of chemisorbed species. In situ high energy resolution fluorescence detection X-ray absorption spectroscopy at the Pt L(3) edge reveals characteristic changes of the shape and intensity of the 'white-line' due to chemisorption of atomic hydrogen (H(ad)) at low potentials and oxygen-containing species (O/OH(ad)) at high potentials. On a uniform, two-dimensional Pt monolayer grown by Pt evaporation in ultrahigh vacuum, we observe a significant destabilization of both H(ad) and O/OH(ad) due to strain and ligand effects induced by the underlying Rh(111) substrate. When Pt is deposited via a wet-chemical route, by contrast, three-dimensional Pt islands are formed. In this case, strain and Rh ligand effects are balanced with higher local thickness of the Pt islands as well as higher defect density, shifting H and OH adsorption energies back toward pure Pt. Using density functional theory, we calculate O adsorption energies and corresponding local ORR activities for fcc 3-fold hollow sites with various local geometries that are present in the three-dimensional Pt islands.

  5. Comparison of Bond Scission Sequence of Methanol on Tungsten Monocarbide and Pt-Modified Tungsten Monocarbide

    SciTech Connect (OSTI)

    Liu, P.; Stottlemyer, A.L.; Chen, J.G.

    2010-09-14T23:59:59.000Z

    The ability to control the bond scission sequence of O-H, C-H, and C-O bonds is of critical importance in the effective utilization of oxygenate molecules, such as in reforming reactions and in alcohol fuel cells. In the current study, we use methanol as a probe molecule to demonstrate the possibility to control the decomposition pathways by supporting monolayer coverage of Pt on a tungsten monocarbide (WC) surface. Density functional theory (DFT) results reveal that on the WC and Pt/WC surfaces CH{sub 3}OH decomposes via O-H bond scission to form the methoxy (*CH{sub 3} O) intermediate. The subsequent decomposition of methoxy on the WC surface occurs through the C-O bond scission to form *CH{sub 3}, which reacts with surface *H to produce CH{sub 4}. In contrast, the decomposition of methoxy on the Pt/WC surface favors the C-H bond scission to produce *CH{sub 2} O, which prevents the formation of the *CH{sub 3} species and leads to the formation of a *CO intermediate through subsequent deprotonation steps. The DFT predictions are validated using temperature programmed desorption to quantify the gas-phase product yields and high resolution electron energy loss spectroscopy to determine the surface intermediates from methanol decomposition on Pt, WC, and Pt/WC surfaces.

  6. EFFECT OF IMPURITIES ON THE PERFORMANCE OF A Pd-Ag DIFFUSER

    SciTech Connect (OSTI)

    Morgan, G.

    2010-12-16T23:59:59.000Z

    A commercially fabricated diffuser purchased from Johnson-Matthey, Inc. was evaluated for performance characterization testing at the Savannah River National Laboratory (SRNL). Different impurities are often present in the feed streams of the process diffusers, but the effect of these impurities on the diffuser performance is currently unknown. Various impurities were introduced into the feed stream of the diffuser at various levels ranging from 0.5% to 10% of the total flow in order to determine the effect that these impurities have on the permeation of hydrogen through the palladium-silver membrane. The introduction of various impurities into the feed stream of the diffuser had a minimal effect on the overall permeation of hydrogen through the Pd-Ag membrane. Of the four impurities introduced into the feed stream, carbon monoxide (CO) was the only impurity that showed any evidence of causing a reduction in the amount of hydrogen permeating through the Pd-Ag membrane. The hydrogen permeation returned to its baseline level after the CO was removed from the feed stream. There were no lasting effects of the CO exposure on the ability of the membrane to effectively separate hydrogen from the non-hydrogen species in the gas stream under the conditions tested.

  7. CHARACTERIZATION OF PD IMPURITIES AND TWIN BOUNDARY DEFECTS IN DETECTOR GRADE CDZNTE CRYSTALS

    SciTech Connect (OSTI)

    Duff, M.

    2011-06-22T23:59:59.000Z

    Synthetic CdZnTe or ''CZT'' crystals are highly suitable for {gamma}-spectrometers operating at the room temperature. Secondary phases (SP) in CZT are known to inhibit detector performance, particularly when they are present in large numbers or dimensions. These SP may exist as voids or composites of non-cubic phase metallic Te layers with bodies of polycrystalline and amorphous CZT material and voids. Defects associated with crystal twining may also influence detector performance in CZT. Using transmission electron microscopy, we identify two types of defects that are on the nano scale. The first defect consists of 40 nm diameter metallic Pd/Te bodies on the grain boundaries of Te-rich composites. Although the nano-Pd/Te bodies around these composites may be unique to the growth source of this CZT material, noble metal impurities like these may contribute to SP formation in CZT. The second defect type consists of atom-scale grain boundary dislocations. Specifically, these involve inclined ''finite-sized'' planar defects or interfaces between layers of atoms that are associated with twins. Finite-sized twins may be responsible for the subtle but observable striations that can be seen with optical birefringence imaging and synchrotron X-ray topographic imaging.

  8. Ag-Pd-Cu alloy inserted transparent indium tin oxide electrodes for organic solar cells

    SciTech Connect (OSTI)

    Kim, Hyo-Joong; Seo, Ki-Won; 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-si, Gyeonggi-do 446-701 (Korea, Republic of); Noh, Yong-Jin; Na, Seok-In [Graduate School of Flexible and Printable Electronics, Chonbuk National University, 664-14, Deokjin-dong, Jeonju-si, Jeollabuk-do 561-756 (Korea, Republic of)

    2014-09-01T23:59:59.000Z

    The authors report on the characteristics of Ag-Pd-Cu (APC) alloy-inserted indium tin oxide (ITO) films sputtered on a glass substrate at room temperature for application as transparent anodes in organic solar cells (OSCs). The effect of the APC interlayer thickness on the electrical, optical, structural, and morphological properties of the ITO/APC/ITO multilayer were investigated and compared to those of ITO/Ag/ITO multilayer electrodes. At the optimized APC thickness of 8?nm, the ITO/APC/ITO multilayer exhibited a resistivity of 8.55?×?10{sup ?5} ? cm, an optical transmittance of 82.63%, and a figure-of-merit value of 13.54?×?10{sup ?3} ?{sup ?1}, comparable to those of the ITO/Ag/ITO multilayer. Unlike the ITO/Ag/ITO multilayer, agglomeration of the metal interlayer was effectively relieved with APC interlayer due to existence of Pd and Cu elements in the thin region of the APC interlayer. The OSCs fabricated on the ITO/APC/ITO multilayer showed higher power conversion efficiency than that of OSCs prepared on the ITO/Ag/ITO multilayer below 10?nm due to the flatness of the APC layer. The improved performance of the OSCs with ITO/APC/ITO multilayer electrodes indicates that the APC alloy interlayer prevents the agglomeration of the Ag-based metal interlayer and can decrease the thickness of the metal interlayer in the oxide-metal-oxide multilayer of high-performance OSCs.

  9. Anomalous codeposition of Fe-Ni alloys and Fe-Ni-SiO{sub 2} composites under potentiostatic conditions: Experimental study and mathematical model

    SciTech Connect (OSTI)

    Ramasubramanian, M.; Popova, S.N.; Popov, B.N.; White, R.E. [Univ. of South Carolina, Columbia, SC (United States). Dept. of Chemical Engineering; Yin, K.M. [Yuan-Ze Inst. of Tech., Taoyuan (Taiwan, Province of China)

    1996-07-01T23:59:59.000Z

    A mathematical model has been developed to describe the electrodeposition of Fe-Ni alloys and Fe-Ni-SiO{sub 2} composites under potentiostatic conditions. This model can be used to predict the polarization behavior, partial current densities, and alloy composition of each of the components as a function of the applied potential. Fe-Ni-SiO{sub 2} samples were deposited on platinum rotating disk electrodes from sulfate electrolytes under potentiostatic conditions, and the results obtained were compared to the model. The model predictions were found to agree well with the experimental observations for the Fe-Ni and Fe-Ni-SiO{sub 2} systems.

  10. CO + O2 and CO + NO Reactions over Pd/Al2O3 Catalysts D. R. Rainer, M. Koranne, S. M. Vesecky, and D. W. Goodman*,

    E-Print Network [OSTI]

    Goodman, Wayne

    CO + O2 and CO + NO Reactions over Pd/Al2O3 Catalysts D. R. Rainer, M. Koranne, S. M. Vesecky. R. Grace and Co., Washington Research Center, Columbia, Maryland 21044, and Monsanto Company, 800 N The kinetics of the CO + NO and CO + O2 reactions have been studied over several different Pd/Al2O3 powder

  11. CO Oxidation over AuPd(100) from Ultrahigh Vacuum to Near-Atmospheric Pressures: CO Adsorption-Induced Surface Segregation and Reaction Kinetics

    E-Print Network [OSTI]

    Goodman, Wayne

    ; ReVised Manuscript ReceiVed: July 7, 2009 Polarization-modulation infrared reflection absorptionCO Oxidation over AuPd(100) from Ultrahigh Vacuum to Near-Atmospheric Pressures: CO Adsorption vacuum (UHV) and near-atmospheric pressures.28 AuPd(100) is a good choice for the study since

  12. Modified Ni-Cu catalysts for ethanol steam reforming

    SciTech Connect (OSTI)

    Dan, M.; Mihet, M.; Almasan, V.; Borodi, G. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Street, 400293, Cluj-Napoca (Romania)] [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Street, 400293, Cluj-Napoca (Romania); Katona, G.; Muresan, L. [Univ. Babes Bolyai, Fac. Chem. and Chem. Eng.,11 Arany Janos, 400028, Cluj-Napoca (Romania)] [Univ. Babes Bolyai, Fac. Chem. and Chem. Eng.,11 Arany Janos, 400028, Cluj-Napoca (Romania); Lazar, M. D., E-mail: diana.lazar@itim-cj.ro [65-103 Donath Street (Romania)

    2013-11-13T23:59:59.000Z

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

  13. Ultra-low loading Pt nanocatalysts prepared by atomic layer deposition on carbon aerogels

    SciTech Connect (OSTI)

    King, J S; Wittstock, A; Biener, J; Kucheyev, S O; Wang, Y M; Baumann, T F; Giri, S; Hamza, A V; Baeumer, M; Bent, S F

    2008-04-21T23:59:59.000Z

    Using atomic layer deposition (ALD), we show that Pt nanoparticles can be deposited on the inner surfaces of carbon aerogels (CA). The resultant Pt-loaded materials exhibit high catalytic activity for the oxidation of CO even at loading levels as low as {approx}0.05 mg Pt/cm{sup 2}. We observe a conversion efficiency of nearly 100% in the temperatures range 150-250 C, and the total conversion rate seems to be only limited by the thermal stability of our CA support in ambient oxygen. Our ALD approach described here is universal in nature, and can be applied to the design of new catalytic materials for a variety of applications, including fuel cells, hydrogen storage, pollution control, green chemistry, and liquid fuel production.

  14. Power-law scaling of asymmetries in viscous flow with PT-symmetric inflow and outflow

    E-Print Network [OSTI]

    Huidan; Yu; Xi Chen; Yousheng Xu; Yogesh N. Joglekar

    2014-10-13T23:59:59.000Z

    In recent years, open systems with balanced loss and gain, that are invariant under the combined parity and time-reversal ($\\mathcal{PT}$) operations, have been studied via asymmetries of their solutions. They represent systems as diverse as coupled optical waveguides and electrical or mechanical oscillators. We numerically investigate the asymmetries of incompressible viscous flow in two and three dimensions with "balanced" inflow-outflow ($\\mathcal{PT}$-symmetric) configurations. By introducing configuration-dependent classes of asymmetry functions in velocity, kinetic energy density, and vorticity fields, we find that the flow asymmetries exhibit power-law scaling with a single exponent in the laminar regime with the Reynolds number ranging over four decades. We show that such single-exponent scaling is expected for small Reynolds numbers, although its robustness at large values of Reynolds numbers is unexpected. Our results imply that $\\mathcal{PT}$-symmetric inflow-outflow configurations provide a hitherto unexplored avenue to tune flow properties.

  15. Swift heavy ion irradiation of Pt nanocrystals: II. Structural changes and H desorption

    SciTech Connect (OSTI)

    Giulian, R.; Araujo, L.L.; Kluth, P.; Sprouster, D.J.; Schnohr, C.S.; Byrne, A.P.; Ridgway, M.C. (ANU)

    2014-09-24T23:59:59.000Z

    The structural properties and H desorption from embedded Pt nanocrystals (NCs) following irradiation with swift heavy ions were investigated as a function of energy and fluence. From x-ray absorption near-edge spectroscopy analysis, Pt-H bonding was identified in NCs annealed in a forming gas (95% N{sub 2} + 5% H{sub 2}) ambient. The H content decreased upon irradiation and the desorption process was NC-size dependent such that larger NCs required a higher fluence to achieve a H-free state. Pt-H bonding and NC dissolution both perturbed the NC structural parameters (coordination number, bond-length and mean-square relative displacement) as determined with extended x-ray absorption fine structure measurements.

  16. [1] P.T. de Zeeuw and C. Hunter. Astrophysical Journal, 356:365, 1990. [2] C. Hunter and P.T. de Zeeuw. Astrophysical Journal, 389:79, 1992.

    E-Print Network [OSTI]

    Terzi, Bal?a

    REFERENCES [1] P.T. de Zeeuw and C. Hunter. Astrophysical Journal, 356:365, 1990. [2] C. Hunter and P.T. de Zeeuw. Astrophysical Journal, 389:79, 1992. [3] F. Bertola and M. Capacciolli. Astrophysical Journal, 200:439, 1975. [4] J. Binney. Comments Astrophysics, 8:27, 1978. [5] M. Schwarzschild

  17. Spin-wave excitation and propagation in microstructured waveguides of yttrium iron garnet/Pt bilayers

    SciTech Connect (OSTI)

    Pirro, P.; Chumak, A. V.; Lägel, B.; Leven, B.; Hillebrands, B. [Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, D-67663 Kaiserslautern (Germany)] [Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, D-67663 Kaiserslautern (Germany); Brächer, T. [Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, D-67663 Kaiserslautern (Germany) [Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, D-67663 Kaiserslautern (Germany); Graduate School Materials Science in Mainz, Gottlieb-Daimler-Strasse 47, D-67663 Kaiserslautern (Germany); Dubs, C.; Surzhenko, O.; Görnert, P. [Innovent e.V., Prüssingstraße 27B, 07745 Jena (Germany)] [Innovent e.V., Prüssingstraße 27B, 07745 Jena (Germany)

    2014-01-06T23:59:59.000Z

    We present an experimental study of spin-wave excitation and propagation in microstructured waveguides consisting of a 100?nm thick yttrium iron garnet/platinum (Pt) bilayer. The life time of the spin waves is found to be more than an order of magnitude higher than in comparably sized metallic structures, despite the fact that the Pt capping enhances the Gilbert damping. Utilizing microfocus Brillouin light scattering spectroscopy, we reveal the spin-wave mode structure for different excitation frequencies. An exponential spin-wave amplitude decay length of 31??m is observed which is a significant step towards low damping, insulator based micro-magnonics.

  18. Fractal Weyl laws for amplified states in PT-symmetric resonators

    E-Print Network [OSTI]

    Christopher Birchall; Henning Schomerus

    2012-08-10T23:59:59.000Z

    We find that in nonhermitian PT-symmetric systems (as realized in resonators with balanced absorption and amplification), a mechanism based on quantum-to-classical correspondence reduces the occurrence of strongly amplified states. The reduction arises from semiclassically emerging hierarchical phase-space structures that are associated with the coupling of the amplifying and absorbing regions (forward and backward-trapped sets and their complements), and amounts to a generalization of the fractal Weyl law, earlier proposed for ballistically open systems. In the context of the recently introduced class of PT-symmetric laser-absorbers, this phenomenon reduces the number of states participating in the mode competition.

  19. Universal routes to spontaneous PT-symmetry breaking in non-Hermitian quantum systems

    SciTech Connect (OSTI)

    Schomerus, Henning [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom)

    2011-03-15T23:59:59.000Z

    PT-symmetric systems can have a real spectrum even when their Hamiltonian is non-Hermitian, but develop a complex spectrum when the degree of non-Hermiticity increases. Here we utilize random-matrix theory to show that this spontaneous PT-symmetry breaking can occur via two distinct mechanisms, whose predominance is associated to different universality classes. Present optical experiments fall into the orthogonal class, where symmetry-induced level crossings render the characteristic absorption rate independent of the coupling strength between the symmetry-related parts of the system.

  20. Scattering of linear and nonlinear waves in a waveguide array with a PT-symmetric defect

    SciTech Connect (OSTI)

    Dmitriev, Sergey V.; Suchkov, Sergey V. [Institute for Metals Superplasticity Problems, Russian Academy of Science, Ufa RU-450001 (Russian Federation); Sukhorukov, Andrey A.; Kivshar, Yuri S. [Nonlinear Physics Centre, Research School of Physics and Engineering,Australian National University, Canberra, ACT 0200 (Australia)

    2011-07-15T23:59:59.000Z

    We study the scattering of linear and nonlinear waves in a long waveguide array with a parity-time (PT)-symmetric defect created by two waveguides with balanced gain and loss. We present exact solutions for the scattering of linear waves on such a defect, and then demonstrate numerically that the linear theory can describe, with a good accuracy, the soliton scattering in the case of weak nonlinearity. We reveal that the reflected and transmitted linear and nonlinear waves can be amplified substantially after interaction with the PT-symmetric defect thus allowing an active control of the wave scattering in the array.

  1. Degenerate four-wave mixing spectroscopy of ultrathin Au and Pt films

    SciTech Connect (OSTI)

    Bobyrev, Yu V; Petnikova, V M; Rudenko, K V; Shuvalov, Vladimir V [International Laser Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation)

    2002-09-30T23:59:59.000Z

    The results of experimental investigations of ultrathin (30 - 40 nm) metal Au and Pt films by means of picosecond degenerate four-wave mixing spectroscopy are presented. Within the model of nonlinear response formation, which takes into account the coherent superposition of contributions from many saturable interband transitions in the real spectrum of electronic states, the characteristic intraband relaxation times are determined to be 230 {+-} 30 fs and 180 {+-} 30 fs for Au and Pt films, respectively. The temperature of the electron subsystem is found to be 600 - 800 K. (nonlinear optical phenomena)

  2. Nanostructured electrocatalyst for fuel cells : silica templated synthesis of Pt/C composites.

    SciTech Connect (OSTI)

    Stechel, Ellen Beth; Switzer, Elise E.; Fujimoto, Cy H.; Atanassov, Plamen Borissov; Cornelius, Christopher James; Hibbs, Michael R.

    2007-09-01T23:59:59.000Z

    Platinum-based electrocatalysts are currently required for state-of-the-art fuel cells and represent a significant portion of the overall fuel cell cost. If fuel cell technology is to become competitive with other energy conversion technologies, improve the utilization of precious metal catalysts is essential. A primary focus of this work is on creating enhanced nanostructured materials which improve precious-metal utilization. The goal is to engineer superior electrocatalytic materials through the synthesis, development and investigation of novel templated open frame structures synthesized in an aerosol-based approach. Bulk templating methods for both Pt/C and Pt-Ru composites are evaluated in this study and are found to be limited due to the fact that the nanostructure is not maintained throughout the entire sample. Therefore, an accurate examination of structural effects was previously impossible. An aerosol-based templating method of synthesizing nanostructured Pt-Ru electrocatalysts has been developed wherein the effects of structure can be related to electrocatalytic performance. The aerosol-based templating method developed in this work is extremely versatile as it can be conveniently modified to synthesize alternative materials for other systems. The synthesis method was able to be extended to nanostructured Pt-Sn for ethanol oxidation in alkaline media. Nanostructured Pt-Sn electrocatalysts were evaluated in a unique approach tailored to electrocatalytic studies in alkaline media. At low temperatures, nanostructured Pt-Sn electrocatalysts were found to have significantly higher ethanol oxidation activity than a comparable nanostructured Pt catalyst. At higher temperatures, the oxygen-containing species contribution likely provided by Sn is insignificant due to a more oxidized Pt surface. The importance of the surface coverage of oxygen-containing species in the reaction mechanism is established in these studies. The investigations in this work present original studies of anion exchange ionomers as entrapment materials for rotating disc electrode (RDE) studies in alkaline media. Their significance is linked to the development of membrane electrode assemblies (MEAs) with the same ionomer for a KOH-free alkaline fuel cell (AFC).

  3. Microsoft Word - AcqGuide38pt Nov 2010 | Department of Energy

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33Frequently Asked Questions forCheneyNovember S. DEPARTMENT OFMonday, December 1, Chapter7pt18pt

  4. Microsoft Word - AcqGuide5pt1 for contracts only may 11 2012 watermark

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33Frequently Asked Questions forCheneyNovember S. DEPARTMENT OFMonday, December 1, Chapter7pt18pt

  5. Mitigation of Sulfur Poisoning of Ni/Zirconia SOFC Anodes by Antimony and Tin

    SciTech Connect (OSTI)

    Marina, Olga A.; Coyle, Christopher A.; Engelhard, Mark H.; Pederson, Larry R.

    2011-02-28T23:59:59.000Z

    Surface Ni/Sb and Ni/Sb alloys were found to efficiently minimize the negative effects of sulfur on the performance of Ni/zirconia anode-supported solid oxide fuel cells (SOFC). Prior to operating on fuel gas containing low concentrations of H2S, the nickel/zirconia anodes were briefly exposed to antimony or tin vapor, which only slightly affected the SOFC performance. During the subsequent exposures to 1 and 5 ppm H2S, increases in anodic polarization losses were minimal compared to those observed for the standard nickel/zirconia anodes. Post-test XPS analyses showed that Sb and Sn tended to segregate to the surface of Ni particles, and further confirmed a significant reduction of adsorbed sulfur on the Ni surface in Ni/Sn and Ni/Sb samples compared to the Ni. The effect may be the result of weaker sulfur adsorption on bimetallic surfaces, adsorption site competition between sulfur and Sb or Sn on Ni, or other factors. The use of dilute binary alloys of Ni-Sb or Ni-Sn in the place of Ni, or brief exposure to Sb or Sn vapor, may be effective means to counteract the effects of sulfur poisoning in SOFC anodes and Ni catalysts. Other advantages, including suppression of coking or tailoring the anode composition for the internal reforming, are also expected.

  6. Electrodeposition and corrosion resistance of Ni-W-B coatings

    SciTech Connect (OSTI)

    Steffani, C.P.; Dini, J.W. [Lawrence Livermore National Lab., CA (United States). Manufacturing and Materials Engineering Div.; Groza, J.R.; Palazoglu, A. [Univ. of California, Davis, CA (United States). Dept. of Chemical Engineering and Materials Science

    1997-08-01T23:59:59.000Z

    A ternary nickel-base alloy Ni-W-B has been developed for surface corrosion and wear resistance to replace chromium plating, which uses environmentally hazardous solutions. The deposition conditions used an alkaline bath and insoluble anodes. The as-deposited alloy typically contains 40 wt% W and 1 wt% B and has an amorphous or partially amorphous structure. These deposits compare favorably with hexavalent chromium deposits in throwing power, color uniformity, and reflectivity. The corrosion resistance of Ni-W-B alloy was compared with hexavalent chromium and electroless nickel deposits in a variety of acids, including hydrochloric, sulfuric, fluoroboric, and phosphoric. In all cases, best results were obtained with the Ni-W-B deposits.

  7. Hydrotreatment of Athabasca bitumen derived gas oil over Ni-Mo, Ni-W, and Co-Mo catalysts

    SciTech Connect (OSTI)

    Diaz-Real, R.A.; Mann, R.S.; Sambi, I.S. (Univ. of Ottawa, Ontario (Canada). Dept. of Chemical Engineering)

    1993-07-01T23:59:59.000Z

    The hydrotreatment of Athabasca bitumen derived heavy gas oil containing 4.08% S and 0.49% N was carried out in a trickle bed reactor over Ni-W, Ni-Mo, and Co-Mo catalysts supported on zeolite-alumina-silica at 623-698 K, LHSV of 1-4, gas flow rate 890 m[sup 3][sub H2]/m[sup 3][sub oil] (5,000 sef/bbl), and pressure of 6.89 MPa. Analyses for viscosity, density, aniline point, ASTM mid boiling point distillation, C/H ratio, and percentage of N and S in the final product were carried out to characterize the product oil. The amounts of N and S removed indicated the hydrodenitrogenation and hydrodesulfurization activity of the catalysts. Results of zeolite-alumina-silica-supported catalysts are compared to those obtained with commercially available Ni-Mo, Ni-W, and Co-Mo on [gamma]-alumina. Ni-Mo supported on zeolite-alumina-silica was most active and could remove as much as 99 % S and 89% N present in the oil at 698 K. The data for HDN and HDS fitted the pseudo first order model. The kinetic model is described in detail.

  8. Chemisorption of (CHx and C2Hy) Hydrocarbons on Pt(111) Clusters and Surfaces from DFT Studies

    E-Print Network [OSTI]

    Goddard III, William A.

    Chemisorption of (CHx and C2Hy) Hydrocarbons on Pt(111) Clusters and Surfaces from DFT Studies Timo that these hydrocarbons all bind covalently (-bonds) to the surface, in agreement with the studies by Kua and Goddard on small Pt clusters. In nearly every case the structure of the adsorbed hydrocarbon achieves a saturated

  9. One-Step Synthesis of FePt Nanoparticles with Tunable Size Min Chen,, J. P. Liu, and Shouheng Sun*,

    E-Print Network [OSTI]

    Liu, J. Ping

    One-Step Synthesis of FePt Nanoparticles with Tunable Size Min Chen,, J. P. Liu, and Shouheng SunPt is coated over the seeds. Although size distribution of the particles prepared from all these methods can of the stabilizers and metal precursors, heating rate, heating temperature, and heating duration. Further, core

  10. Atomistic modeling of the directed-assembly of bimetallic Pt-Ru nanoclusters on Ru(0001)-supported monolayer graphene

    E-Print Network [OSTI]

    Ulm, Universität

    )-supported monolayer graphene Yong Han,1 Albert K. Engstfeld,2 R. Juergen Behm,2 and James W. Evans1,3,* 1 of Pt-Ru nanoclusters (NC's) by sequential deposition of Pt and Ru on a periodically rumpled graphene. The periodic variation of the adsorption energy across the graphene sheet directs the assembly of NC

  11. Oxygen-assisted room-temperature deposition of CoPt3 films with perpendicular magnetic anisotropy

    E-Print Network [OSTI]

    Hellman, Frances

    Oxygen-assisted room-temperature deposition of CoPt3 films with perpendicular magnetic anisotropy B Jolla, California 92093 Received 23 July 2002; accepted 30 September 2002 Trace amounts of oxygen CoPt3 grown by vapor deposition at or slightly above room temperature. Oxygen is known to act

  12. hal-00196134,version1-12Dec2007 Analysis of anisotropy crossover due to oxygen in Pt/Co/MOx

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    hal-00196134,version1-12Dec2007 Analysis of anisotropy crossover due to oxygen in Pt/Co/MOx-ray spectroscopy measurements have been performed on a se- ries of Pt/Co/MOx trilayers (M=Al, Mg, Ta...) in order to investigate the role of oxidation in the onset of perpendicular magnetic anisotropy at the Co/MOx interface

  13. Tunable, long-wavelength PtSi/SiGe/Si Schottky diode infrared detectors J. R. Jimeneza)

    E-Print Network [OSTI]

    Tunable, long-wavelength PtSi/SiGe/Si Schottky diode infrared detectors J. R. Jimeneza) Faura, Massachusetts 01731 Received 9 March 1995; accepted for publication 31 May 1995 We have fabricated p-type PtSi/SiGe dependent on the applied bias. The variability in the barrier height is obtained by using the SiGe

  14. Generation of 2D and 3D (PtS, Adamantanoid) Nets with a Flexible Tetrahedral Building Block

    SciTech Connect (OSTI)

    Tian, Jian; Motkuri, Radha K.; Thallapally, Praveen K.

    2010-09-01T23:59:59.000Z

    The self-assembly of a flexible tetrahedral linker tetrakis[4-(carboxyphenyl)oxamethyl]methane acid with various transition metals (Cu, Co and Mg) results in a 2D layered structure and 3D frameworks with PtS and adamantanoid topology. The PtS net exhibits permanent porosity as confirmed by BET and gas adsorption experiments.

  15. Electrochromic devices embodying W oxide/Ni oxide tandem films

    SciTech Connect (OSTI)

    Azens, A.; Vaivars, G.; Veszelei, M.; Kullman, L.; Granqvist, C. G.

    2001-06-15T23:59:59.000Z

    Six-layer electrochromic devices of indium tin oxide (ITO)/NiO{sub x}H{sub y}/WO{sub 3}/ZrP-electrolyte/WO{sub 3}/ITO were made by reactive dc magnetron sputtering and lamination. The WO{sub 3} layer between the acidic ZrP-based electrolyte and the NiO{sub x}H{sub y} layer served as optically passive protective layer. The optical inactivity of the protective layer could be understood from arguments based on electron density of states. {copyright} 2001 American Institute of Physics.

  16. The uncertainties of a Pd3PGV onsite earthquake early warning system Jui-Pin Wang a,n

    E-Print Network [OSTI]

    Wu, Yih-Min

    The uncertainties of a Pd3­PGV onsite earthquake early warning system Jui-Pin Wang a,n , Yih-Min Wu should be issued, based on factors such as the uncertainty of the early warning system, the magnitude the development and implementation of earthquake early warning systems. This study examines the uncertainty of one

  17. Unoccupied electronic states of icosahedral Al-Pd-Mn quasicrystals: Evidence of image potential resonance and pseudogap

    SciTech Connect (OSTI)

    Maniraj, M [UGC-DAE Confortium for Scientific Research; Rai, Abhishek [UGC-DAE Confortium for Scientific Research; Barman, S R [UGC-DAE Confortium for Scientific Research; Krajci, M [Slovak Academy of Sciences; Schlagel, Deborah L [Ames Laboratory; Lograsso, Thomas A [Ames Laboratory; Horn, K [Fritz-Haber-Institut der Max-Planck-Gesellschaft

    2014-09-01T23:59:59.000Z

    We study the unoccupied region of the electronic structure of the fivefold symmetric surface of an icosahedral (i) Al-Pd-Mn quasicrystal. A feature that exhibits parabolic dispersion with an effective mass of (1.15±0.1)me and tracks the change in the work function is assigned to an image potential resonance because our density functional calculation shows an absence of band gap in the respective energy region. We show that Sn grows pseudomorphically on i?Al?Pd?Mn as predicted by density functional theory calculations, and the energy of the image potential resonance tracks the change in the work function with Sn coverage. The image potential resonance appears much weaker in the spectrum from the related crystalline Al-Pd-Mn surface, demonstrating that its strength is related to the compatibility of the quasiperiodic wave functions in i?Al?Pd?Mn with the free-electron-like image potential states. Our investigation of the energy region immediately above EF provides unambiguous evidence for the presence of a pseudogap, in agreement with our density functional theory calculations.

  18. Electronic Friction Dominates Hydrogen Hot-Atom Relaxation on Pd(100) M. Blanco-Rey,1,2

    E-Print Network [OSTI]

    Muiño, Ricardo Díez

    initio molecular dynamics simulations that include a friction force to account for the energy transfer February 2014; published 14 March 2014) We study the dynamics of transient hot H atoms on Pd(100 to the electronic system. We find that the excitation of electron-hole pairs is the main channel for energy

  19. Synthesis and study of ligands for Pd-catalyzed C-O and C-N coupling

    E-Print Network [OSTI]

    Davis, Nicole R. (Nicole Rose)

    2009-01-01T23:59:59.000Z

    A new ligand, AdBrettPhos, was synthesized and its use, along with tBuBrettPhos, in C-O coupling reactions at low temperatures was investigated. Using Pd catalysts containing these ligands, electron-neutral aryl bromides ...

  20. Synthesis and characterization of the Au-modified Pd cathode catalyst for alkaline direct ethanol fuel cells

    E-Print Network [OSTI]

    Zhao, Tianshou

    Available online 3 August 2010 Keywords: Fuel cell Alkaline direct ethanol fuel cell Oxygen reduction Carbon in large quantities from agricultural products or biomass. Hence, direct ethanol fuel cells (DEFCs) haveSynthesis and characterization of the Au-modified Pd cathode catalyst for alkaline direct ethanol

  1. Monte Carlo calculations and experimental measurements of dosimetric parameters of the IRA-{sup 103}Pd brachytherapy source

    SciTech Connect (OSTI)

    Sadeghi, Mahdi; Raisali, Gholamreza; Hosseini, S. Hamed; Shavar, Arzhang [Nuclear Medicine Research Group, Agricultural, Medical and Industrial Research School, P.O. Box 31485-498, Karaj (Iran, Islamic Republic of) and Engineering Faculty, Science and Research Campus, Islamic Azad University, P.O. Box 14515-775, Tehran (Iran, Islamic Republic of); Radiation Applications Research School, Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Engineering Faculty, Science and Research Campus, Islamic Azad University, P.O. Box 14515-775, Tehran (Iran, Islamic Republic of); SSDL Group, Agricultural, Medical and Industrial Research School, Karaj (Iran, Islamic Republic of)

    2008-04-15T23:59:59.000Z

    This article presents a brachytherapy source having {sup 103}Pd adsorbed onto a cylindrical silver rod that has been developed by the Agricultural, Medical, and Industrial Research School for permanent implant applications. Dosimetric characteristics (radial dose function, anisotropy function, and anisotropy factor) of this source were experimentally and theoretically determined in terms of the updated AAPM Task group 43 (TG-43U1) recommendations. Monte Carlo simulations were used to calculate the dose rate constant. Measurements were performed using TLD-GR200A circular chip dosimeters using standard methods employing thermoluminescent dosimeters in a Perspex phantom. Precision machined bores in the phantom located the dosimeters and the source in a reproducible fixed geometry, providing for transverse-axis and angular dose profiles over a range of distances from 0.5 to 5 cm. The Monte Carlo N-particle (MCNP) code, version 4C simulation techniques have been used to evaluate the dose-rate distributions around this model {sup 103}Pd source in water and Perspex phantoms. The Monte Carlo calculated dose rate constant of the IRA-{sup 103}Pd source in water was found to be 0.678 cGy h{sup -1} U{sup -1} with an approximate uncertainty of {+-}0.1%. The anisotropy function, F(r,{theta}), and the radial dose function, g(r), of the IRA-{sup 103}Pd source were also measured in a Perspex phantom and calculated in both Perspex and liquid water phantoms.

  2. Excited-state properties of platinum(II) complexes containing biphenyl as a ligand: Complexes of the type [(bph)PtL[sub 2

    SciTech Connect (OSTI)

    Blanton, C.B.; Murtaza, Z.; Shaver, R.J.; Rillema, D.P. (Univ. of North Carolina, Charlotte (United States))

    1992-07-22T23:59:59.000Z

    The preparation, physical properties, and photophysical properties of [Pt(bph)(C[sub 2]H[sub 5])[sub 2]S][sub 2], [Pt(bph)(CH[sub 3]CN)[sub 2

  3. High performance 70 nm In0.8GaP/In0.4AlAs/In0.35GaAs Metamorphic HEMT With Pd Schottky Contacts

    E-Print Network [OSTI]

    Seo, Kwang Seok

    contacts, due to low diffusivity with InGaP of Pd as well as its high SBH [9], the distance between Schottky contact due to its low diffusion of Pd to InGaP. The fabricated 70 nm MHEMT's with Pd Schottky

  4. A Hydrogen-Evolving Ni(P2N2)2 Electrocatalyst Covalently Attached...

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

    A Hydrogen-Evolving Ni(P2N2)2 Electrocatalyst Covalently Attached to a Glassy Carbon Electrode: Preparation, Characterization, A Hydrogen-Evolving Ni(P2N2)2 Electrocatalyst...

  5. SciTech Connect: Neutron Scattering of CeNi at the SNS-ORNL:...

    Office of Scientific and Technical Information (OSTI)

    Conference: Neutron Scattering of CeNi at the SNS-ORNL: A Preliminary Report Citation Details In-Document Search Title: Neutron Scattering of CeNi at the SNS-ORNL: A Preliminary...

  6. Proton Delivery and Removal in [Ni(PR2NR?2)2]2+ Hydrogen...

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

    Delivery and Removal in Ni(PR2NR?2)22+ Hydrogen Production and Oxidation Catalysts. Proton Delivery and Removal in Ni(PR2NR?2)22+ Hydrogen Production and Oxidation...

  7. Dynamical deformation effects in subbarrier fusion of $^{64}$Ni+$^{132}$Sn

    E-Print Network [OSTI]

    A. S. Umar; V. E. Oberacker

    2006-09-25T23:59:59.000Z

    We show that dynamical deformation effects play an important role in fusion reactions involving the $^{64}$Ni nucleus, in particular the $^{64}$Ni+$^{132}$Sn system. We calculate fully microscopic interaction potentials and the corresponding subbarrier fusion cross sections.

  8. Study of Martensitic Phase transformation in a NiTiCu Thin Film...

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

    Martensitic Phase transformation in a NiTiCu Thin Film Shape Memory Alloy Using Photoelectron Emission Microscopy. Study of Martensitic Phase transformation in a NiTiCu Thin Film...

  9. Bulk Glass Formation in Eutectic of La-Cu-Ni-Al Metallic Alloys

    E-Print Network [OSTI]

    Zhang, Yong

    A eutectic in La-rich La-Cu?.?Ni?.?-Al alloys was determined by studying the melting behaviors and the microstructure observations. The microstructures of the La-Cu-Ni-Al alloys prepared by ...

  10. Origin of transverse magnetization in epitaxial Cu/Ni/Cu nanowire arrays

    E-Print Network [OSTI]

    Ciria, M.

    The patterning-induced changes in the magnetic anisotropy and hysteresis of epitaxial (100)-oriented Cu/Ni(9, 10, 15 nm)/Cu planar nanowires have been quantified. When the Ni films are patterned into lines, strain relaxation ...

  11. Assessing the Bioavailability of Ni in Smelter Contaminated Soils. (S11-everhart242852-oral)

    E-Print Network [OSTI]

    Sparks, Donald L.

    Assessing the Bioavailability of Ni in Smelter Contaminated Soils. (S11-everhart242852-oral efforts. In this study, Welland Loam and Quarry Muck soils contaminated with Ni from a smelter facility

  12. A MOSSBAUER STUDY OF AUSTENITE STABILITY AND IMPACT FRACTURE IN Fe - 6 Ni STEEL

    E-Print Network [OSTI]

    Fultz, Brent

    2011-01-01T23:59:59.000Z

    IMPACT FRACTURE IN Fe-6Ni STEEL Brent Thomas Fultz Materialscommercial cryogenic alloy steel was studied with regard toThe Experiments Fe-6Ni-lMn steel plate was received from the

  13. WELDABILITY OF GRAIN-REFINED Fe-12Ni-0.25Ti STEEL FOR CRYOGENIC APPLICATIONS

    E-Print Network [OSTI]

    Morris Jr., J.W.

    2013-01-01T23:59:59.000Z

    of the Cryogenic Nickel Steels, WRC Bull, 205, May, 1975.REFINED Fe-12Ni-0.25Ti STEEL FOR CRYOGENIC APPLICATIONS D.E.REFINED Fe-12Ni-0.25Ti STEEL FOR CRYOGENIC APPLICATIONS D.

  14. Surface Segregation in a PdCu Alloy Hydrogen Separation Membrane

    SciTech Connect (OSTI)

    Miller, J.B.; Matranga, C.S.; Gellman, A.J.

    2007-06-01T23:59:59.000Z

    Separation of hydrogen from mixed gas streams is an important step for hydrogen generation technologies, including hydrocarbon reforming and coal/biomass gasification. Dense palladium-based membranes have received significant attention for this application because of palladium’s ability to dissociatively adsorb molecular hydrogen at its surface for subsequent transport of hydrogen atoms through its bulk. Alloying palladium with minor components, like copper, has been shown to improve both the membrane’s structural characteristics and resistance to poisoning of its catalytic surface [1]. Surface segregation—a composition difference between the bulk material and its surface—is common in alloys and can affect important surface processes. Rational design of alloy membranes requires that surface segregation be understood, and possibly controlled. In this work, we examine surface segregation in a polycrystalline Pd70Cu30 hydrogen separation membrane as a function of thermal treatment and adsorption of hydrogen sulfide.

  15. Pygmy resonance and low-energy enhancement in the $?$-ray strength functions of Pd~isotopes

    E-Print Network [OSTI]

    Tomas Kvalheim Eriksen; Hilde-Therese Nyhus; Magne Guttormsen; Andreas Görgen; Ann-Cecilie Larsen; Therese Renstrøm; Inger-Eli Ruud; Sunniva Siem; Heidi Kristine Toft; Gry Merete Tveten; Jonathan Wilson

    2014-08-22T23:59:59.000Z

    An unexpected enhancement in the $\\gamma$-ray strength function, as compared to the low energy tail of the Giant Dipole Resonance (GDR), has been observed for Sc, Ti, V, Fe and Mo isotopes for $E_\\gamma4$ MeV, which is interpreted as a PDR centered at $E_{\\gamma}\\approx8$ MeV. An enhanced $\\gamma$-ray strength at low energies is also observed for $^{105}$Pd, which is the lightest isotope measured in this work. Further, the results correspond and agree very well with the observations from the Cd isotopes, and support the suggested transitional region for the onset of low-energy enhancement with decreasing mass number. The neutron number dependency of the PDR strength is also evident.

  16. Calorimetry study of the synthesis of amorphous Ni-Ti alloys by mechanical alloying. [Ni33 Ti67

    SciTech Connect (OSTI)

    Schwarz, R.B.; Petrich, R.R.

    1988-01-01T23:59:59.000Z

    We synthesized amorphous Ni/sub 33/Ti/sub 67/ alloy powder by ball milling (a) a mixture of elemental nickel and titanium powders and (b) powders of the crystalline intermetallic NiTi/sub 2/. We characterized the reaction products as a function of ball-milling time by differential scanning calorimetry and x-ray diffraction. The measurements suggest that in process (a) the amorphous alloy forms by a solid-state interdiffusion reaction at the clean Ni/Ti interfaces generated by the mechanical attrition. In process (b), the crystalline alloy powder stores energy in the form of chemical disorder and lattice and point defects. The crystal-to-amorphous transformation occurs when the stored energy reaches a critical value. The achievement of the critical stored energy competes with the dynamic recovery of the lattice. 23 refs., 7 figs.

  17. Superior performance of Ni-W-Ce mixed-metal oxide catalysts for ethanol steam reforming: Synergistic effects of W- and Ni-dopants

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

    Rodriguez, Jose A. [Brookhaven National Lab. (BNL), Upton, NY (United States); State Univ. of New York Stony Brook, Stony Brook, NY (United States); Liu, Zongyuan [Brookhaven National Lab. (BNL), Upton, NY (United States); State Univ. of New York Stony Brook, Stony Brook, NY (United States); Xu, Wenqian [Brookhaven National Lab. (BNL), Upton, NY (United States); Yao, Siyu [Brookhaven National Lab. (BNL), Upton, NY (United States); Johnson-Peck, Aaron C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zhao, Fuzhen [Brookhaven National Lab. (BNL), Upton, NY (United States); Michorczyk, Piotr [Inst. de Catalisis y Petroleoquimica, Madrid (Spain); Kubacka, Anna [Inst. de Catalisis y Petroleoquimica, Madrid (Spain); Stach, Eric A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Fernandez-Garica, Marcos [State Univ. of New York Stony Brook, Stony Brook, NY (United States); Senanayake, Sanjaya D. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-01-01T23:59:59.000Z

    The ethanol steam reforming (ESR) reaction was studied over a series of Ni-W-Ce oxide catalysts. The structures of the catalysts were characterized using in-situ techniques including X-ray diffraction, Pair Distribution Function, X-ray absorption fine structure and transmission electron microscopy; while possible surface intermediates for the ESR reaction were investigated by Diffuse Reflectance Infrared Fourier Transform Spectroscopy. In these materials, all the W and part of the Ni were incorporated into the CeO? lattice, with the remaining Ni forming highly dispersed nano NiO (< 2 nm) outside the Ni-W-Ce oxide structure. The nano NiO was reduced to Ni under ESR conditions. The Ni-W-Ce systeme exhibited a much larger lattice strain than those seen for Ni-Ce and W-Ce. Synergistic effects between Ni and W inside ceria produced a substantial amount of defects and O vacancies that led to high catalytic activity, selectivity and stability (i.e. resistance to coke formation) during ethanol steam reforming.

  18. Superior performance of Ni-W-Ce mixed-metal oxide catalysts for ethanol steam reforming: Synergistic effects of W- and Ni-dopants

    SciTech Connect (OSTI)

    Rodriguez, Jose A. [Brookhaven National Lab. (BNL), Upton, NY (United States); State Univ. of New York Stony Brook, Stony Brook, NY (United States); Liu, Zongyuan [Brookhaven National Lab. (BNL), Upton, NY (United States); State Univ. of New York Stony Brook, Stony Brook, NY (United States); Xu, Wenqian [Brookhaven National Lab. (BNL), Upton, NY (United States); Yao, Siyu [Brookhaven National Lab. (BNL), Upton, NY (United States); Johnson-Peck, Aaron C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zhao, Fuzhen [Brookhaven National Lab. (BNL), Upton, NY (United States); Michorczyk, Piotr [Inst. de Catalisis y Petroleoquimica, Madrid (Spain); Kubacka, Anna [Inst. de Catalisis y Petroleoquimica, Madrid (Spain); Stach, Eric A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Fernandez-Garica, Marcos [State Univ. of New York Stony Brook, Stony Brook, NY (United States); Senanayake, Sanjaya D. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-01-01T23:59:59.000Z

    The ethanol steam reforming (ESR) reaction was studied over a series of Ni-W-Ce oxide catalysts. The structures of the catalysts were characterized using in-situ techniques including X-ray diffraction, Pair Distribution Function, X-ray absorption fine structure and transmission electron microscopy; while possible surface intermediates for the ESR reaction were investigated by Diffuse Reflectance Infrared Fourier Transform Spectroscopy. In these materials, all the W and part of the Ni were incorporated into the CeO? lattice, with the remaining Ni forming highly dispersed nano NiO (< 2 nm) outside the Ni-W-Ce oxide structure. The nano NiO was reduced to Ni under ESR conditions. The Ni-W-Ce systeme exhibited a much larger lattice strain than those seen for Ni-Ce and W-Ce. Synergistic effects between Ni and W inside ceria produced a substantial amount of defects and O vacancies that led to high catalytic activity, selectivity and stability (i.e. resistance to coke formation) during ethanol steam reforming.

  19. Development of a new electrodeposition process for plating of Zn-Ni-X (X=Cd, P) alloys. 1. Corrosion characteristics of Zn-Ni-Cd ternary alloys

    SciTech Connect (OSTI)

    Durairajan, A.; Haran, B.S.; White, R.E.; Popov, B.N.

    2000-05-01T23:59:59.000Z

    A new Zn-Ni-Cd plating process was developed which offers a unique way of controlling and optimizing the Ni and Cd contents in the final deposit. Zinc-nickel-cadmium alloy was deposited from a 0.5 M NiSO{sub 4} + 0.2 M ZnSO{sub 4} bath in the presence of 0.015 M CdSO{sub 4} and 1 g/L nonyl phenyl polyethylene oxide. Using this process a Zn-Ni-Cd ternary alloy, with a higher nickel content as compared to that obtained from conventional Zn-Ni baths, was synthesized. The Zn-Ni-Cd alloy coatings deposited from an electrolyte containing 0.015 M (0.3%) CdSO{sub 4} has a Zn to Ni ratio of 2.5:1. The increase in nickel content accounts for the observed decrease in the corrosion potential to a value lower than that of Cd but higher than the corrosion potential of iron. The coatings have superior corrosion resistance and barrier properties than the typical Zn-Ni and cadmium coatings. Polarization studies and electrochemical impedance spectroscopy analysis on Zn-Ni-Cd coatings show a barrier resistance that is ten times higher than that of a conventional Zn-Ni coating.

  20. SISGR: Theoretically relating the surface composition of Pt alloys to their performance as the electrocatalysts of low-temperature fuel cells

    SciTech Connect (OSTI)

    Wang, Guofeng

    2010-12-31T23:59:59.000Z

    The main goal of this project is to gain fundamental knowledge about the relation between surface composition and catalytic performance of Pt alloy catalysts for oxygen reduction reaction (ORR). Specific objectives are: to develop and improve a first-principles based multiscale computation approach to simulating surface segregation phenomena in Pt alloy surfaces; to evaluate the surface electronic structure and catalytic activity of Pt alloy catalysts and; to relate the surface composition to the catalytic performance of Pt alloy catalysts.