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Sample records for ag pd tizrv

  1. Research on the secondary electron yield of tizrv-pd thin film coatings

    CERN Document Server

    Wang, Jie; Zhang, Bo; Wang, Yong; Wei, Wei

    2015-01-01

    In particle accelerators, the build-up of electron cloud may have important influence on beam quality. Especially for the positron and proton accelerators, massive electrons lead to electron cloud, which affects the stability, energy, emittance and beam life adversely. A secondary electron emission (SEE) measurement system has been designed and used to study the SEE of palladium (Pd), TiZrV and TiZrV-Pd with an independently adjustable energy from 50 eV to 5 keV. Here, we obtained the characteristics of the SEE from Pd, TiZrV and TiZrV-Pd film coatings with different thickness under ultrahigh-vacuum (UHV) conditions. Moreover, the maximum secondary electron yield (SEY), {\\delta}max, of the Pd, TiZrV and TiZrV-Pd film coatings under different primary electron doses were obtained, respectively. Finally, the variation of the secondary electron yield with the incident electron energy will be discussed for Pd, TiZrV and TiZrV-Pd thin film coatings. Low SEY is a new advantage of TiZrV-Pd films, besides high H2 abso...

  2. Partial phase diagram of Pd-Ag-Ru-Gd quaternary system

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    On the basis of the Ag-Pd-Gd, Ag-Ru-Gd and Pd-Ru-Gd ternary systems, the partial phase diagram of Pd-Ag-Ru-Gd(Gd<25% atom fraction) quaternary system has been studied by means of X-ray diffraction analysis, differential thermal analysis, electron probe microanalysis and optical microscopy.The 700℃ isothermal sections of the Ag-Pd-5Ru-Gd, Ag-Pd-20Ru-Gd and Ag-Pd-50Ru-Gd (Gd≤25%atom fraction) phase diagrams were determined respectively. And the 700℃ isothermal section of the PdAg-Ru-Gd (Gd≤25% atom fraction) quaternary system phase diagram was finally irferred. The section consists of four single-phase regions: solid solution Pd(Ag), (Ru), Pd3Gd and Ag51 Gd14; five two-phase regions: Pd(Ag) + (Ru), Pd(Ag) + Ag51 Gd14 , (Ru) + Ag51 Gd14 , Pd(Ag) + Pd3Gd and (Ru) +Pd3Gd; three three-phase regions: Pd(Ag) + Pd3Gd+ (Ru), Pd(Ag) + Ag51Gd14 + (Ru) and (Ru) +Ag51Gd14 + Pd3Gd; one four-phase region Pd(Ag) + (Ru) + Ag51Gd14 + Pd3Gd. No new quaternary intermetallic phase is found.

  3. Monodispersed bimetallic PdAg nanoparticles with twinned structures: Formation and enhancement for the methanol oxidation

    OpenAIRE

    Zhen Yin; Yining Zhang; Kai Chen; Jing Li; Wenjing Li; Pei Tang; Huabo Zhao; Qingjun Zhu; Xinhe Bao; Ding Ma

    2014-01-01

    Monodispersed bimetallic PdAg nanoparticles can be fabricated through the emulsion-assisted ethylene glycol (EG) ternary system. Different compositions of bimetallic PdAg nanoparticles, Pd80Ag20, Pd65Ag35 and Pd46Ag54 can be obtained via adjusting the reaction parameters. For the formation process of the bimetallic PdAg nanoparticles, there have two-stage growth processes: firstly, nucleation and growth of the primary nanoclusters; secondly, formation of the secondary nanoparticles with the s...

  4. X-ray diffraction study of thermal parameters of Pd, Pd-Ag and Pd-Ag-Cu alloys as hydrogen purification membrane materials

    Science.gov (United States)

    Pati, Subhasis; Jat, Ram Avtar; Mukerjee, S. K.; Parida, S. C.

    2016-03-01

    High temperature X-ray diffraction measurements were carried out for pure palladium and palladium-rich alloys of compositions Pd0.77Ag0.23 and Pd0.77Ag0.10Cu0.13 in the temperature range of 298-1023 K at an interval of 50 K. The lattice parameters, coefficient of thermal expansion and X-ray Debye temperature of these materials were calculated as a function of temperature from the XRD data. The lattice parameter of Pd0.77Ag0.23 alloy was found to be higher than that of palladium, whereas the lattice parameter of Pd0.77Ag0.10Cu0.13 was found to be lower than that of palladium in the temperature range of investigation. Further, the lattice parameters of both the palladium alloys show negative deviation from Vegard's law and the deviation was found to increase with increase in temperature. The average value of coefficient of linear thermal expansion was found to follow the trend: αT (Pd)>αT (Pd0.77Ag0.23)>αT (Pd0.77Ag0.10Cu0.13). The X-ray Debye temperatures of Pd0.77Ag0.23 and Pd0.77Ag0.10Cu0.13 alloys were calculated and found to be 225±10 and 165±10 K, respectively.

  5. Comparison of Ti/Pd/Ag, Pd/Ti/Pd/Ag and Pd/Ge/Ti/Pd/Ag contacts to n-type GaAs for electronic devices handling high current densities

    Science.gov (United States)

    Huo, Pengyun; Galiana, Beatriz; Rey-Stolle, Ignacio

    2017-04-01

    In the quest for metal contacts for electronic devices handling high current densities, we report the results of Pd/Ti/Pd/Ag and Pd/Ge/Ti/Pd/Ag contacts to n-GaAs and compare them to Ti/Pd/Ag and AuGe/Ni/Au. These metal systems have been designed with the goal of producing an electrical contact with (a) low metal–semiconductor specific contact resistance, (b) very high sheet conductance, (c) good bondability, (d) long-term durability and (e) cost-effectiveness. The structure of the contacts consists of an interfacial layer (either Pd or Pd/Ge) intended to produce a low metal–semiconductor specific contact resistance; a diffusion barrier (Ti/Pd) and a thick top layer of Ag to provide the desired high sheet conductance, limited cost and good bondability. The results show that both systems can achieve very low metal resistivity (ρ M ∼ 2 × 10‑6 Ω cm), reaching values close to that of pure bulk silver. This fact is attributed to the Ti/Pd bilayer acting as an efficient diffusion barrier, and thus the metal sheet resistance can be controlled by the thickness of the deposited silver layer. Moreover, the use of Pd as interfacial layer produces contacts with moderate specific contact resistance (ρ C ∼ 10‑4 Ω cm2) whilst the use of Pd/Ge decreases the specific contact resistance to ρ C ∼ 1.5 × 10‑7 Ω cm2, as a result of the formation of a Pd4(GaAs, Ge2) compound at the GaAs interface.

  6. Synthesis of Pt, Pd, Pt/Ag and Pd/Ag nanoparticles by microwave-polyol method

    Indian Academy of Sciences (India)

    Kirti Patel; Sudhir Kapoor; Devilal Purshottam Dave; Tulsi Mukherjee

    2005-07-01

    Pt, Pd, Pt-Ag and Pd-Ag bimetallic nanoparticles were synthesized in ethylene glycol and glycerol using the microwave technique in the presence of a stabilizer poly(N-vinylpyrrolidone) (PVP). It has been observed that PVP is capable of complexing and stabilizing nanoparticles. Mixed clusters were formed by simultaneous reduction of the metal ions. The clusters were characterized using UV-Vis spectra, XRD and dynamic light scattering. To understand the mechanism of formation of mixed nanoparticles, several experimental parameters such as in situ irradiation of mixed metal salts and mixing of individual sols were attempted.

  7. Controllable galvanic synthesis of triangular Ag-Pd alloy nanoframes for efficient electrocatalytic methanol oxidation.

    Science.gov (United States)

    Xu, Lin; Luo, Zhimin; Fan, Zhanxi; Yu, Sijia; Chen, Junze; Liao, Yusen; Xue, Can

    2015-06-08

    Triangular Ag-Pd alloy nanoframes were successfully synthesized through galvanic replacement by using Ag nanoprisms as sacrificial templates. The ridge thickness of the Ag-Pd alloy nanoframes could be readily tuned by adjusting the amount of the Pd source during the reaction. These obtained triangular Ag-Pd alloy nanoframes exhibit superior electrocatalytic activity for the methanol oxidation reaction as compared with the commercial Pd/C catalyst due to the alloyed Ag-Pd composition as well as the hollow-framed structures. This work would be highly impactful in the rational design of future bimetallic alloy nanostructures with high catalytic activity for fuel cell systems.

  8. Highly Active Carbon Supported Pd-Ag Nanofacets Catalysts for Hydrogen Production from HCOOH.

    Science.gov (United States)

    Wang, Wenhui; He, Ting; Liu, Xuehua; He, Weina; Cong, Hengjiang; Shen, Yangbin; Yan, Liuming; Zhang, Xuetong; Zhang, Jinping; Zhou, Xiaochun

    2016-08-17

    Hydrogen is regarded as a future sustainable and clean energy carrier. Formic acid is a safe and sustainable hydrogen storage medium with many advantages, including high hydrogen content, nontoxicity, and low cost. In this work, a series of highly active catalysts for hydrogen production from formic acid are successfully synthesized by controllably depositing Pd onto Ag nanoplates with different Ag nanofacets, such as Ag{111}, Ag{100}, and the nanofacet on hexagonal close packing Ag crystal (Ag{hcp}). Then, the Pd-Ag nanoplate catalysts are supported on Vulcan XC-72 carbon black to prevent the aggregation of the catalysts. The research reveals that the high activity is attributed to the formation of Pd-Ag alloy nanofacets, such as Pd-Ag{111}, Pd-Ag{100}, and Pd-Ag{hcp}. The activity order of these Pd-decorated Ag nanofacets is Pd-Ag{hcp} > Pd-Ag{111} > Pd-Ag{100}. Particularly, the activity of Pd-Ag{hcp} is up to an extremely high value, i.e., TOF{hcp} = 19 000 ± 1630 h(-1) at 90 °C (lower limit value), which is more than 800 times higher than our previous quasi-spherical Pd-Ag alloy nanocatalyst. The initial activity of Pd-Ag{hcp} even reaches (3.13 ± 0.19) × 10(6) h(-1) at 90 °C. This research not only presents highly active catalysts for hydrogen generation but also shows that the facet on the hcp Ag crystal can act as a potentially highly active catalyst.

  9. Adsorption of atomic oxygen on PdAg/Pd(111) surface alloys and coadsorption of CO

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, Arnold P. [Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm (Germany); Reaction Kinetics Research Group, University of Szeged, Chemical Research Center of the Hungarian Academy of Sciences, H-6720 Szeged (Hungary); Bansmann, Joachim; Diemant, Thomas; Behm, R. Juergen [Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm (Germany)

    2011-07-01

    The interaction of dissociated oxygen with structurally well-defined PdAg/Pd(111) surface alloys and the coadsorption of CO was studied by high resolution electron energy loss spectroscopy (HREELS) and temperature-programmed desorption (TPD). After oxygen saturation of the non-modified Pd(111) surface at RT, we observed the formation of a prominent peak in the HREEL spectra at 60 meV corresponding to the perpendicular vibration of oxygen atoms adsorbed in threefold hollow sites. Deposition of small Ag amounts does not change the signal intensity of this peak; it decreases only above 20% Ag. Beyond this Ag content, the peak intensity steeply declines and disappears at around 55-60% Ag. CO coadsorption on the oxygen pre-covered surfaces at 120 K leads to the formation of additional features in HREELS. For a surface alloy with 29% Ag, three loss features due to CO adsorption in on-top, bridge, and threefold-hollow sites can be discriminated already after the lowest CO exposure. Annealing of the co-adsorbed layer to 200 K triggers a decrease of the oxygen concentration due to CO{sub 2} formation. These findings are corroborated by TPD spectra of the CO desorption and CO{sub 2} production.

  10. Triangular Ag-Pd alloy nanoprisms: rational synthesis with high-efficiency for electrocatalytic oxygen reduction

    Science.gov (United States)

    Xu, Lin; Luo, Zhimin; Fan, Zhanxi; Zhang, Xiao; Tan, Chaoliang; Li, Hai; Zhang, Hua; Xue, Can

    2014-09-01

    We report the generation of triangular Ag-Pd alloy nanoprisms through a rationally designed synthetic strategy based on silver nanoprisms as sacrificial templates. The galvanic replacement between Ag nanoprisms and H2PdCl4 along with co-reduction of Ag+/Pd2+ is responsible for the formation of final prismatic Ag-Pd alloy nanostructures. Significantly, these Ag-Pd alloy nanoprisms exhibited superior electrocatalytic activity for the oxygen reduction reaction (ORR) as compared with the commercial Pd/C catalyst. Such a high catalytic activity is attributed to not only the alloyed Ag-Pd composition but also the dominant {111} facets of the triangular Ag-Pd nanoprisms. This work demonstrates the rational design of bimetallic alloy nanostructures with control of selective crystal facets that are critical to achieve high catalytic activity for fuel cell systems.We report the generation of triangular Ag-Pd alloy nanoprisms through a rationally designed synthetic strategy based on silver nanoprisms as sacrificial templates. The galvanic replacement between Ag nanoprisms and H2PdCl4 along with co-reduction of Ag+/Pd2+ is responsible for the formation of final prismatic Ag-Pd alloy nanostructures. Significantly, these Ag-Pd alloy nanoprisms exhibited superior electrocatalytic activity for the oxygen reduction reaction (ORR) as compared with the commercial Pd/C catalyst. Such a high catalytic activity is attributed to not only the alloyed Ag-Pd composition but also the dominant {111} facets of the triangular Ag-Pd nanoprisms. This work demonstrates the rational design of bimetallic alloy nanostructures with control of selective crystal facets that are critical to achieve high catalytic activity for fuel cell systems. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr03600j

  11. Electrochemical Fabrication of Pd-Ag Alloy Nanowire Arrays in Anodic Alumina Oxide Template

    Institute of Scientific and Technical Information of China (English)

    Erhong YUE; Gang YU; Yuejun OUYANG; Baicheng WENG; Weiwei SI; Liyuan YE

    2008-01-01

    The synthesis of Pd-Ag alloy nanowires in nanopores of porous anodic aluminum oxide (AAO) template by electrochemical deposition technique was reported.Pd-Ag alloy nanowires with 16%-25% Ag content are expected to serve as candidates of useful nanomaterials for the hydrogen sensors.Scanning electron microscopy (SEM) and energy dispersed X-ray spectroscopy (EDX) were employed to characterize the morphologies and compositions of the Pd-Ag nanowires.X-ray diffraction (XRD) was used to characterize the phase properties of the Pd-Ag nanowires.Pd-Ag alloy nanowire arrays with 17.28%-23.76% Ag content have been successfully fabricated by applying potentials ranging from -0.8 to -1.0 V (vs SCE).The sizes of the alloy nanowires are in agreement with the diameter of AAO nanopores.The underpotential deposition of Ag+ on Pd and Au plays an important role in producing an exceptionally high Ag content in the alloy.Alloy compositions can still be controlled by adjusting the ion concentration ratio of Pd2+ and Ag+ and the electrodeposition processes.XRD shows that nanowires obtained are in the form of alloy of Pd and Ag.

  12. Intermetallic Phase on the Interface of Ag-Au-Pd/Al Structure

    Directory of Open Access Journals (Sweden)

    Hao-Wen Hsueh

    2014-01-01

    Full Text Available Three wires, Au, Cu, and Ag-Au-Pd, were bonded on an Al pad, inducing IMC growth by a 155 hr high temperature storage (HTS so that the electrical resistance was increased and critical fusing current density (CFCD decreased. Observations of the Ag-Au-Pd wire after HTS (0–1000 hr indicated that IMC between the Ag-Au-Pd wire and Al Pad was divided into three layers: Ag2Al layers above and below the bonding interface and a polycrystal thin layer above the total IMC. A high percentage of Pd and Au existed in this 200 nm thin layer, and could suppress Al diffusion into the Ag matrix to inhibit IMC growth. After PCT-1000 hr, a noncontinuous structure still remained between the IMC layer and interface, and the main phase of IMC was (Ag, Au, Pd2Al with a hexagonal structure.

  13. Design of PdAg Hollow Nanoflowers through Galvanic Replacement and Their Application for Ethanol Electrooxidation.

    Science.gov (United States)

    Bin, Duan; Yang, Beibei; Zhang, Ke; Wang, Caiqin; Wang, Jin; Zhong, Jiatai; Feng, Yue; Guo, Jun; Du, Yukou

    2016-11-07

    In this study, galvanic replacement provides a simple route for the synthesis of PdAg hollow nanoflower structures by using the Ag-seeds as sacrificial templates in the presence of l-ascorbic acid (reductant) and CTAC (capping agent). Transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and EDS mapping were used to characterize the as-prepared PdAg hollow nanoflower catalysts, where they were alloyed nanoflower structures with hollow interiors. By maneuvering the Pd/Ag ratio, we found that the as-prepared Pd1 Ag3 hollow nanoflower catalysts had the optimized performance for catalytic activity toward ethanol oxidation reaction. Moreover, these as-prepared PdAg hollow nanoflower catalysts exhibited noticeably higher electrocatalytic activity as compared to pure Pd and commercial Pd/C catalysts due to the alloyed Ag-Pd composition as well as the hollow nanoflower structures. It is anticipated that this work provides a rational design of other architecturally controlled bimetallic nanocrystals for application in fuel cells.

  14. Development of highly transparent Pd-coated Ag nanowire electrode for display and catalysis applications

    Energy Technology Data Exchange (ETDEWEB)

    Canlier, Ali, E-mail: ali.canlier@agu.edu.tr [Department of Materials Science and Nanotechnology Engineering, Abdullah Gul University, P.O. Box 38080, Kayseri (Turkey); Ucak, Umit Volkan, E-mail: sirvolkan@gmail.com [Department of Materials Science and Nanotechnology Engineering, Abdullah Gul University, P.O. Box 38080, Kayseri (Turkey); Graduate School of Energy, Environment, Water, and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), P.O. Box 305-701, Daejeon (Korea, Republic of); Usta, Hakan, E-mail: husta38@gmail.com [Department of Materials Science and Nanotechnology Engineering, Abdullah Gul University, P.O. Box 38080, Kayseri (Turkey); Cho, Changsoon, E-mail: cscho@kaist.ac.kr [Graduate School of Energy, Environment, Water, and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), P.O. Box 305-701, Daejeon (Korea, Republic of); Lee, Jung-Yong, E-mail: jungyong.lee@kaist.ac.kr [Graduate School of Energy, Environment, Water, and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), P.O. Box 305-701, Daejeon (Korea, Republic of); Sen, Unal, E-mail: senunal@gmail.com [Department of Mechanical Engineering, Abdullah Gul University, P.O. Box 38080, Kayseri (Turkey); Citir, Murat, E-mail: muratcitir@gmail.com [Department of Chemical Engineering, Abdullah Gul University, P.O. Box 38080, Kayseri (Turkey)

    2015-09-30

    Highlights: • Highly uniform thin-layer coating of Pd onto Ag nanowire surface was accomplished. • A transparent electrode of Pd-coated Ag nanowire was uniformly deposited on flexible substrate. • 95% of optical transmittance and 175 Ω/sq sheet resistance were obtained. • Extremely low haze of 1.9% and high oxidation stability proved an efficient transparent electrode. • This electrode can be used as Pd-catalyst for synthesis reactions and fuel cell electrode applications. - Abstract: Ag nanowire transparent electrode has excellent transmittance (90%) and sheet resistance (20 Ω/sq), yet there are slight drawbacks such as optical haze and chemical instability against aerial oxidation. Chemical stability of Ag nanowires needs to be improved in order for it to be suitable for electrode applications. In our recent article, we demonstrated that coating Ag nanowires with a thin layer of Au through galvanic exchange reactions enhances the chemical stability of Ag nanowire films highly and also helps to obtain lower haze. In this study, coating of a thin Pd layer has been applied successfully onto the surface of Ag nanowires. A mild Pd complex oxidant [Pd(en){sub 2}](NO{sub 3}){sub 2} was prepared in order to oxidize Ag atoms partially on the surface via galvanic displacement. The mild galvanic exchange allowed for a thin layer (1–2 nm) of Pd coating on the Ag nanowires with minimal truncation of the nanowire, where the average length and the diameter were 12.5 μm and 59 nm, respectively. The Pd-coated Ag nanowires were suspended in methanol and then electrostatically sprayed on flexible polycarbonate substrates. It has been revealed that average total transmittance remain around 95% within visible spectrum region (400–800 nm) whereas sheet resistance rises up to 175 Ω/sq. To the best of our knowledge, for the first time in the literature, Pd coating was employed on Ag nanowires in order to design transparent electrodes for high transparency and strong

  15. Core-shell Au@Pd nanoparticles with enhanced catalytic activity for oxygen reduction reaction via core-shell Au@Ag/Pd constructions.

    Science.gov (United States)

    Chen, Dong; Li, Chengyin; Liu, Hui; Ye, Feng; Yang, Jun

    2015-07-06

    Core-shell nanoparticles often exhibit improved catalytic properties due to the lattice strain created in these core-shell particles. Herein, we demonstrate the synthesis of core-shell Au@Pd nanoparticles from their core-shell Au@Ag/Pd parents. This strategy begins with the preparation of core-shell Au@Ag nanoparticles in an organic solvent. Then, the pure Ag shells are converted into the shells made of Ag/Pd alloy by galvanic replacement reaction between the Ag shells and Pd(2+) precursors. Subsequently, the Ag component is removed from the alloy shell using saturated NaCl solution to form core-shell Au@Pd nanoparticles with an Au core and a Pd shell. In comparison with the core-shell Au@Pd nanoparticles upon directly depositing Pd shell on the Au seeds and commercial Pd/C catalysts, the core-shell Au@Pd nanoparticles via their core-shell Au@Ag/Pd templates display superior activity and durability in catalyzing oxygen reduction reaction, mainly due to the larger lattice tensile effect in Pd shell induced by the Au core and Ag removal.

  16. Effects of Supports and Promoter Ag on Pd Catalysts for Selective Hydrogenation of Acetylene

    Institute of Scientific and Technical Information of China (English)

    朱淑映; 侯瑞君; 王铁峰

    2012-01-01

    SiO2,α-Al2O3,γ-Al2O3,ZrO2 and CeO2 were used as supports and Ag as promoter to study their effects on Pd catalysts for selective hydrogenation of acetylene.The catalysts were prepared by impregnated synthesis and characterized by XRD,BET and TEM.The catalytic reaction was carried out in a fixed-bed reactor.Overall,the low specific surface area supports were better to increase the ethylene selectivity at high conversion rate of acetylene.Among the four Pd catalysts on low specific surface area supports,the catalyst on low specific surface area SiO2 (LSA-SiO2) retained a high ethylene selectivity even at complete conversion,while the other catalysts showed significant decrease in the selectivity at complete conversion.The performance of Pd/LSA-SiO2 was important to decrease the loss of ethylene in selective hydrogenation of trace acetylene in ethylene.Addition of Ag to Pd/LSA-SiO2 significantly decreased the formation of ethane,C4 alkenes and green oil,and improved the ethylene selectivity to 90% when Pd∶Ag=1∶1 and 1∶3(ω).When the ratio of Pd to Ag was above 1,the activity of Pd-Ag bimetallic catalyst was similar to that of Pd monometallic catalyst,and the selectivity of ethylene increased with increasing of amount of Ag.When the ratio of Pd to Ag was below 1,the activity of bimetallic catalyst decreased with increasing of amount of Ag,while the selectivity of ethylene was kept unchanged.The optimum temperature was 200~230 ℃ for 0.02%(ω)Pd-0.02%( ω)Ag/LSA-SiO2 to give a high ethylene selectivity and low formation of green oil.

  17. Nanoparticles alloying in liquids: Laser-ablation-generated Ag or Pd nanoparticles and laser irradiation-induced AgPd nanoparticle alloying

    Science.gov (United States)

    Semaltianos, N. G.; Chassagnon, R.; Moutarlier, V.; Blondeau-Patissier, V.; Assoul, M.; Monteil, G.

    2017-04-01

    Laser irradiation of a mixture of single-element micro/nanomaterials may lead to their alloying and fabrication of multi-element structures. In addition to the laser induced alloying of particulates in the form of micro/nanopowders in ambient atmosphere (which forms the basis of the field of additive manufacturing technology), another interesting problem is the laser-induced alloying of a mixture of single-element nanoparticles in liquids since this process may lead to the direct fabrication of alloyed-nanoparticle colloidal solutions. In this work, bare-surface ligand-free Ag and Pd nanoparticles in solution were prepared by laser ablation of the corresponding bulk target materials, separately in water. The two solutions were mixed and the mixed solution was laser irradiated for different time durations in order to investigate the laser-induced nanoparticles alloying in liquid. Nanoparticles alloying and the formation of AgPd alloyed nanoparticles takes place with a decrease of the intensity of the surface-plasmon resonance peak of the Ag nanoparticles (at ∼405 nm) with the irradiation time while the low wavelength interband absorption peaks of either Ag or Pd nanoparticles remain unaffected by the irradiation for a time duration even as long as 30 min. The nanoalloys have lattice constants with values between those of the pure metals, which indicates that they consist of Ag and Pd in an approximately 1:1 ratio similar to the atomic composition of the starting mixed-nanoparticle solution. Formation of nanoparticle networks consisting of bimetallic alloyed nanoparticles and nanoparticles that remain as single elements (even after the end of the irradiation), joining together, are also formed. The binding energies of the 3d core electrons of both Ag and Pd nanoparticles shift to lower energies with the irradiation time, which is also a typical characteristic of AgPd alloyed nanoparticles. The mechanisms of nanoparticles alloying and network formation are also

  18. Nanoparticles alloying in liquids: Laser-ablation-generated Ag or Pd nanoparticles and laser irradiation-induced AgPd nanoparticle alloying.

    Science.gov (United States)

    Semaltianos, N G; Chassagnon, R; Moutarlier, V; Blondeau-Patissier, V; Assoul, M; Monteil, G

    2017-04-18

    Laser irradiation of a mixture of single-element micro/nanomaterials may lead to their alloying and fabrication of multi-element structures. In addition to the laser induced alloying of particulates in the form of micro/nanopowders in ambient atmosphere (which forms the basis of the field of additive manufacturing technology), another interesting problem is the laser-induced alloying of a mixture of single-element nanoparticles in liquids since this process may lead to the direct fabrication of alloyed-nanoparticle colloidal solutions. In this work, bare-surface ligand-free Ag and Pd nanoparticles in solution were prepared by laser ablation of the corresponding bulk target materials, separately in water. The two solutions were mixed and the mixed solution was laser irradiated for different time durations in order to investigate the laser-induced nanoparticles alloying in liquid. Nanoparticles alloying and the formation of AgPd alloyed nanoparticles takes place with a decrease of the intensity of the surface-plasmon resonance peak of the Ag nanoparticles (at ∼405 nm) with the irradiation time while the low wavelength interband absorption peaks of either Ag or Pd nanoparticles remain unaffected by the irradiation for a time duration even as long as 30 min. The nanoalloys have lattice constants with values between those of the pure metals, which indicates that they consist of Ag and Pd in an approximately 1:1 ratio similar to the atomic composition of the starting mixed-nanoparticle solution. Formation of nanoparticle networks consisting of bimetallic alloyed nanoparticles and nanoparticles that remain as single elements (even after the end of the irradiation), joining together, are also formed. The binding energies of the 3d core electrons of both Ag and Pd nanoparticles shift to lower energies with the irradiation time, which is also a typical characteristic of AgPd alloyed nanoparticles. The mechanisms of nanoparticles alloying and network formation are also

  19. Novel PdAgCu ternary alloy: Hydrogen permeation and surface properties

    Energy Technology Data Exchange (ETDEWEB)

    Tarditi, Ana M.; Braun, Fernando [Instituto de Investigaciones en Catalisis y Petroquimica (FIQ, UNL-CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina); Cornaglia, Laura M., E-mail: lmcornag@fiq.unl.edu.ar [Instituto de Investigaciones en Catalisis y Petroquimica (FIQ, UNL-CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina)

    2011-05-15

    Dense PdAgCu ternary alloy composite membranes were synthesized by the sequential electroless plating of Pd, Ag and Cu on top of both disk and tubular porous stainless steel substrates. X-ray diffraction and scanning electron microscopy were employed to study the structure and morphology of the tested samples. The hydrogen permeation performance of these membranes was investigated over a 350-450 deg. C temperature range and a trans-membrane pressure up to 100 kPa. After annealing at 500 deg. C in hydrogen stream followed by permeation experiments, the alloy layer presented a FCC crystalline phase with a bulk concentration of 68% Pd, 7% Ag and 25% Cu as revealed by EDS. The PdAgCu tubular membrane was found to be stable during more than 300 h on hydrogen stream. The permeabilities of the PdAgCu ternary alloy samples were higher than the permeabilities of the PdCu alloy membranes with a FCC phase. The co-segregation of silver and copper to the membrane surface was observed after hydrogen permeation experiments at high temperature as determined by XPS.

  20. Polarization-sensitive photocurrent in the resistive Ag/Pd films

    Science.gov (United States)

    Saushin, A. S.; Zonov, R. G.; Mikheev, K. G.; Shamshetdinov, R. R.; Mikheev, G. M.

    2016-08-01

    We report on the observation of helicity dependent photocurrent of the 20 μm thick silver-palladium (Ag/Pd) films manufactured by the thick-film technology. The transverse photocurrent is observed at oblique incidence of laser radiation with different wavelengths in the spectral range of 266 - 2100 nm. At the wavelength range of 532 - 2100 nm the polarity of the transverse photocurrent is positive (negative) for the left- (right-) circular polarized beam. We show that action of high temperature on the films in vacuum results in the decrease of longitudinal photocurrent due to the reduction of PdO content. The photon drag effect is suggested to be the origin of the polarization-sensitive photocurrent in the Ag/Pd films. The obtained results show that the Ag/Pd resistive films may be of interest for polarization- sensitive measurements.

  1. Preparation and characterization of Pd-Ag alloy composite membrane with magnetron sputtering

    Institute of Scientific and Technical Information of China (English)

    赵宏宾[1; 熊国兴[2; N.Stroh[3; H.Brunner[4

    1999-01-01

    A Pd-Ag (24 wt%) alloy composite membrane was prepared by the magnetron sputtering. A γ-Al2O3 membrane was synthesized by the sol-gel method and used as substrate of the Pd-Ag alloy film. The process parameters of the magnetron sputtering were optimized as a function of the compactness of the Pd-Ag alloy film. The best membrane with a thickness of 1 μm was produced with a sputtering pressure of 2.7 Pa and a substrate temperature of 400℃. The membrane had an H2/N2 permselectivity of 51.5--1000 and an H2 permeation rate of 0.036--1.17×10-5cm3/cm2·s· Pa, depending on operating conditions.

  2. Highly energetic nonequilibrium microstructure fabricated by ion beam manipulation in the Ag-Pd system

    CERN Document Server

    Li, Z C

    2003-01-01

    An artificial ordered layered structure of high energy was obtained by a form of ion beam manipulation, namely interface-assisted ion beam mixing, of appropriately designed nano-sized Ag-Pd multilayered films, in which the interfacial free energy elevated the Ag-Pd multilayered films to near to the corresponding highly energetic state. Diffraction analysis suggested that the ordered layered structure consisted of two overlapped face-centred-cubic lattices with lattice constants smaller than those of both pure Ag and pure Pd. The growth mechanism was also discussed in terms of a dynamic atomic collision, followed by a relaxation lasting for an extremely short time, involved in the irradiation process.

  3. Solvent and stabilizer free growth of Ag and Pd nanoparticles using metallic salts/cyclotriphosphazenes mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Díaz Valenzuela, C. [Departamento de Química, Facultad de Química, Universidad de Chile, La Palmeras 3425, Nuñoa, Casilla 653, Santiago de Chile (Chile); Valenzuela, M.L., E-mail: mlvalenzuela@unab.cl [Universidad Andres Bello, Departamento de Ciencias Química, Facultad de Ciencias Exactas, Av. Republica 275, Santiago (Chile); Caceres, S.; Diaz, R. [Departamento de Química, Facultad de Química, Universidad de Chile, La Palmeras 3425, Nuñoa, Casilla 653, Santiago de Chile (Chile); O' Dwyer, C. [Applied Nanoscience Group, Department of Chemistry, University College Cork, Cork (Ireland); Micro and Nanoelectronics Centre, Tyndall National Institute, Lee Maltings, Cork (Ireland)

    2013-12-16

    Cyclotriphosphazene is used as a sacrificial solid-state template to synthesize a range of Ag and Pd nanoparticles with diverse geometries by thermal treatment using MLn/N{sub 3}P{sub 3}(O{sub 2}C{sub 12}H{sub 8}){sub 3} mixtures. The Pd and Ag nanoparticles are synthesized by solid-state pyrolysis of AgPPh{sub 3}[CF{sub 3}SO{sub 3}]/N{sub 3}P{sub 3}(O{sub 2}C{sub 12}H{sub 8}){sub 3} and PdCl{sub 2}/N{sub 3}P{sub 3}(O{sub 2}C{sub 12}H{sub 8}){sub 3} mixtures with molar relationships of 1:1, 1:5 and 1:10 respectively, in air and at 800 °C. The morphology of the as-prepared nanoparticles is found to depend on the molar ratio of the precursor mixture, the preparation method and of the nature of the metal. Ag and Pd, microcrystals were thermally grown on Si from the respective 1:1 precursors while that metal foams were grown from 1:5 ratios precursors on SiO{sub 2} wafers. High resolution transmission electron microscopy investigations reveal in most cases small crystals of Pd. HRSTEM measurements indicate that the formation of the Pd and Ag nanoparticles occurs through a phase demixing and dewetting mechanism. This approach has potential to be a useful and facile method to prepare metallic nanoparticles without requiring solutions or surfactants for application in electronic, catalytic and sensor materials and devices. - Highlights: • Pyrolysis MLn/N{sub 3}P{sub 3}(O{sub 2}C{sub 12}H{sub 8}){sub 3} mixtures under air, give Pd and Ag nanoparticles. • AgPPh{sub 3}[CF{sub 3}SO{sub 3}] and PdCl{sub 2} in molar ratios 1:1 and 1:5 were used. • Metal foams were obtained from 1:5 ratios when deposited on SiO{sub 2.} • Using crucible supporting in 1:1 metal/trimer <2 nm Pd nanoparticles were obtained. • The probable mechanism involves a dewetting, nucleation and ripening crystallization.

  4. Facile synthesis of PdAgTe nanowires with superior electrocatalytic activity

    Science.gov (United States)

    Hong, Wei; Wang, Jin; Wang, Erkang

    2014-12-01

    In this work, ultrathin Te nanowires (NWs) with high-aspect-ratio are prepared by a simple hydrothermal method. By using Te NWs as the sacrificial template, we demonstrate a facile and efficient method for the synthesis of PdAgTe NWs with high-quality through the partly galvanic replacement between Te NWs and the corresponding noble metal salts precursors in an aqueous solution. The compositions of PdAgTe NWs can be tuned by simply altering the concentration of the precursors. After cyclic voltammetry treatment, multi-component PdAgTe NW with a highly active and stable surface can be obtained. The structure and composition of the as-prepared nanomaterials are analyzed by transmission electron microscope, X-ray diffraction, energy dispersive X-ray spectroscopy, inductively coupled plasma-mass spectroscopy and X-ray photoelectron spectroscopy. Electrochemical catalytic measurement results prove that the as synthesized PdAgTe NWs present superior catalytic activity toward ethanol electrooxidation in alkaline solution than the commercial Pd/C catalyst, which making them can be used as effective catalysts for the direct ethanol fuel cells.

  5. Pd@Ag Nanosheets in Combination with Amphotericin B Exert a Potent Anti-Cryptococcal Fungicidal Effect.

    Directory of Open Access Journals (Sweden)

    Chao Zhang

    Full Text Available Silver nanoparticles have received considerable interest as new "nanoantibiotics" with the potential to kill drug-resistant microorganisms. Recently, a class of new core-shell nanostructures, Pd@Ag nanosheets (Pd@Ag NSs, were created using deposition techniques and demonstrated excellent inhibitory effects on various bacteria in vitro. In this study, we evaluated the antifungal activity of Pd@Ag NSs against common invasive fungal pathogens. Among these organisms, Cryptococcus neoformans complex species was most susceptible to Pd@Ag NSs, which exhibited potent antifungal activity against various molecular types or sources of cryptococcal strains including fluconazole-resistant isolates. The anticryptococcal activity of Pd@Ag NSs was significantly greater than fluconazole and similar to that of amphotericin B (AmB. At relatively high concentrations, Pd@Ag NSs exhibited fungicidal activity against Cryptococcus spp., which can likely be attributed to the disruption of cell integrity, intracellular protein synthesis, and energy metabolism. Intriguingly, Pd@Ag NSs also exhibited strong synergistic anti-cryptococcal fungicidal effects at low concentrations in combination with AmB but exhibited much better safety in erythrocytes than AmB, even at the minimal fungicidal concentration. Therefore, Pd@Ag NSs may be a promising adjunctive agent for treating cryptococcosis, and further investigation for clinical applications is required.

  6. The Role of Pd in Sn-Ag-Cu Solder Interconnect Mechanical Shock Performance

    Science.gov (United States)

    Lee, Tae-Kyu; Zhou, Bite; Bieler, Thomas R.; Tseng, Chien-Fu; Duh, Jeng-Gong

    2013-02-01

    The mechanical stability of solder joints with Pd added to Sn-Ag-Cu alloy with different aging conditions was investigated in a high- G level shock environment. A test vehicle with three different strain and shock level conditions in one board was used to identify the joint stability and failure modes. The results revealed that Pd provided stability at the package-side interface with an overall shock performance improvement of over 65% compared with the Sn-Ag-Cu alloy without Pd. A dependency on the pad structure was also identified. However, the strengthening mechanism was only observed in the non-solder mask defined (NSMD) pad design, whereas the solder mask defined (SMD) pad design boards showed no improvement in shock performance with Pd-added solders. The effects of Sn grain orientation on shock performance, interconnect stability, and crack propagation path with and without Pd are discussed. The SAC305 + Pd solder joints showed more grain refinements, recrystallization, and especially mechanical twin deformation during the shock test, which provides a partial explanation for the ability of SAC305 + Pd to absorb more shock-induced energy through active deformation compared with SAC305.

  7. H{sub 2} reduction of surface oxides on Pd-based membrane model systems – The case of Pd(1 0 0) and Pd{sub 75}Ag{sub 25}(1 0 0)

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, V.R. [Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Gustafson, J. [Division of Synchrotron Radiation Research, Lund University, Box 117, SE-221 00 Lund (Sweden); Farstad, M.H.; Walle, L.E. [Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Blomberg, S.; Lundgren, E. [Division of Synchrotron Radiation Research, Lund University, Box 117, SE-221 00 Lund (Sweden); Venvik, H.J. [Department of Chemical Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Borg, A., E-mail: anne.borg@ntnu.no [Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway)

    2014-09-15

    Highlights: • H{sub 2} reduction of the surface oxide is significantly slower for Pd{sub 75}Ag{sub 25}(1 0 0) compared to Pd(1 0 0). • The reduction behavior shows complex temperature dependence, not well described by Avrami kinetics. • Oxygen spillover effects during the surface oxide reduction are observed for Pd(1 0 0). • For Pd(1 0 0) the observed reduction rate is rather independent of temperature. • For Pd{sub 75}Ag{sub 25}(1 0 0) the reduction rate displays a non-monotonic variation with temperature. - Abstract: Reduction of the (√(5)×√(5))R27° surface oxide on Pd(1 0 0) and Pd{sub 75}Ag{sub 25}(1 0 0) surfaces by H{sub 2} has been studied using high-resolution photoelectron spectroscopy in situ at H{sub 2} pressures 5 × 10{sup −9} mbar and 5 × 10{sup −8} mbar and selected temperatures in the range 30 °C to 170 °C. The reduction is slower on Pd{sub 75}Ag{sub 25}(1 0 0) compared to Pd(1 0 0) for all temperatures and pressures investigated. For Pd(1 0 0), the surface oxide reduction rate is rather independent of temperature, while for Pd{sub 75}Ag{sub 25}(1 0 0) a non-monotonic variation is observed. As indicated by kinetic analysis, the complex reduction behavior is not well described by Avrami kinetics. Oxygen spillover effects contribute to this picture for Pd(1 0 0), while surface compositional effects appear to dominate the performance for Pd{sub 75}Ag{sub 25}(1 0 0). These findings may have implications for understanding the oxidation, reduction and hydrogen transport properties of Pd–Ag membranes.

  8. Electrocatalytic Oxidation of Formic Acid in an Alkaline Solution with Graphene-Oxide- Supported Ag and Pd Alloy Nanoparticles.

    Science.gov (United States)

    Han, Hyoung Soon; Yun, Mira; Jeong, Haesang; Jeon, Seungwon

    2015-08-01

    The electrocatalytic activities of metal-decorated graphene oxide (GO) catalysts were investigated. Electrochemically reduced GO-S-(CH2)4-S-Pd [ERGO-S-(CH2)4-S-Pd] and GO-S-(CH2)4-S-PdAg alloy [ERGO-S-(CH2)4-S-PdAg] were obtained through the electrochemical reduction of GO-S-(CH2)4-S-Pd and GO-S-(CH2)4-S-PdAg in a pH 5 PBS solution. It was demonstrated that the application of ERGO-S-(CH2)4-S-Pd and ERGO-S-(CH2)4-S-PdAg used in a modified GCE improves the electrocatalytic oxidation of formic acid. The addition of an Ag nanoparticle with a carbon chain-Pd in the electrode provides an electrode with very interesting properties for the electrocatalytic oxidation of formic acid. The ERGO-S-(CH2)4-S-Pd and ERGO-S-(CH2)4-S-PdAg were characterized via X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). ERGO-S-(CH2)4-S-Pd and ERGO-S-(CH2)4-S-PdAg can be employed for the electrocatalytic oxidation of formic acid. The electrochemical behaviors of this electrode were investigated using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS).

  9. Morphology and N2 Permeance of Sputtered Pd-Ag Ultra-Thin Film Membranes

    Directory of Open Access Journals (Sweden)

    Ekain Fernandez

    2016-02-01

    Full Text Available The influence of the temperature during the growth of Pd-Ag films by PVD magnetron sputtering onto polished silicon wafers was studied in order to avoid the effect of the support roughness on the layer growth. The surfaces of the Pd-Ag membrane films were analyzed by atomic force microscopy (AFM, and the results indicate an increase of the grain size from 120 to 250–270 nm and film surface roughness from 4–5 to 10–12 nm when increasing the temperature from around 360–510 K. After selecting the conditions for obtaining the smallest grain size onto silicon wafer, thin Pd-Ag (0.5–2-µm thick films were deposited onto different types of porous supports to study the influence of the porous support, layer thickness and target power on the selective layer microstructure and membrane properties. The Pd-Ag layers deposited onto ZrO2 3-nm top layer supports (smallest pore size among all tested present high N2 permeance in the order of 10−6 mol·m−2·s−1·Pa−1 at room temperature.

  10. Characterization and electrocatalytic properties of sonochemical synthesized PdAg nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Godinez-Garcia, Andres, E-mail: agodinez@qro.cinvestav.mx [Depto. Materiales, Centro de Investigacion y de Estudios Avanzados del IPN, Libramiento norponiente 2000, Fracc. Real de Juriquilla, C.P. 76230 Santiago de Queretaro, Qro. (Mexico); Perez-Robles, Juan Francisco [Depto. Materiales, Centro de Investigacion y de Estudios Avanzados del IPN, Libramiento norponiente 2000, Fracc. Real de Juriquilla, C.P. 76230 Santiago de Queretaro, Qro. (Mexico); Martinez-Tejada, Hader Vladimir [Grupo de Energia y Termodinamica, Universidad Pontificia Bolivariana, Medellin, Antioquia C.P. 050031 (Colombia); Solorza-Feria, Omar [Depto. Quimica, CINVESTAV-IPN, Av. IPN 2508, A. P. 14-740, 07360 D.F. Mexico (Mexico)

    2012-06-15

    High intensity ultrasound was used in the synthesis of PdAg nanoparticles. PdAg nanoparticles were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS), scanning transmission electron microscopy (STEM) and high-resolution transmission electron microscopy (HRTEM). Catalytic properties for oxygen reduction reaction (ORR) were determined by electrochemical techniques of cyclic voltammetry (CV) and thin-film rotating disk electrode (TF-RDE). Finally the electrocatalyst was tested as a cathode in a single polymer electrolyte membrane fuel cell (PEMFC). Sonochemical synthesis (SS) decreased the overpotential required for the ORR and increased the double-layer capacitance (DLC) respect to the sodium borohydride reduction method due to a better distribution on vulcan carbon support. The electrocatalytic activity of the nanometric bimetallic electrocatalyst for the ORR in acid media showed a favorable multielectron charge transfer process (n = 4e{sup -}) to water formation. The performance of the membrane electrode assembly (MEA) prepared with dispersed PdAg/C as a cathode catalyst in a single PEMFC is lower in comparison to platinum. - Highlights: Black-Right-Pointing-Pointer Sonochemical synthesized PdAg nanoparticles supported on carbon were produced. Black-Right-Pointing-Pointer The material showed catalytic properties for the oxygen reduction reaction (ORR). Black-Right-Pointing-Pointer The ORR favored the pathway to water formation.

  11. Spectroscopic Characterization of Stability and Interaction of Pd-Ag Complexes

    Directory of Open Access Journals (Sweden)

    Sharad V. Lande

    2014-01-01

    Full Text Available Colloidal metal nanoparticles are of great interest because of their use as catalysts, photocatalysts, adsorbents, and sensors as well as their application in optical, electronic, and magnetic devices. Supported bimetallic systems represent a large part of heterogeneous catalysts which have been used in various reactions important in the chemical, petrochemical, and oil industry. Pd-Ag bimetallic nanocatalysts have become vitally important in some of the petrochemical industry’s processes like hydrogenation of C2–C5 olefins. A heat-treatment method for the preparation of well-stable Pd-Ag complexes is demonstrated using water, concentrated HCl and concentrated nitric acid as media. The stability and interaction of Pd-Ag complexes were characterized by UV-vis absorption spectroscopy. Pd-Ag bimetallic nanoparticles of spherical cubic and octahedral shape in the range of average particle size of 20–60 nm have been prepared and characterized by transmission electron microscopy (TEM.

  12. DFT study of selective hydrogenation of acetylene to ethylene on Pd doping Ag nanoclusters

    Science.gov (United States)

    Liu, D.

    2016-11-01

    Recently, it has been reported that the reaction selectivity of catalytic hydrogenation of acetylene to ethylene can be significantly enhanced via the approach of Pd mono-atomic catalysis [Pei et al. ACS Catal. 5 (2015) 3717-3725]. To explain the catalytic mechanism of this binary alloy catalyst, C2H2 hydrogenation reactions on Pd doping Ag nanoclusters are studied using density functional theory simulations. The simulation results indicate that H2 and C2H2 can simultaneously bind with a single Pd doping atom no matter it is on vertex and edge sites of Ag clusters. The following H2 dissociation and C2H2 hydrogenation are not difficult since the corresponding reaction barrier values are no more than 0.58 eV. The generated C2H4 molecule can not be further hydrogenated since it locates on the top of Pd doping atom, which is the only adsorption site for H2. On two Pd doping atoms at contiguous sites of Ag clusters, C2H4 hydrogenation reactions can be carried out since there are enough sites for co-adsorption of H2 and C2H4.

  13. DFT study of selective hydrogenation of acetylene to ethylene on Pd doping Ag nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    Liu, D., E-mail: liud@ysu.edu.cn

    2016-11-15

    Graphical abstract: The co-adsorption of H{sub 2} and C{sub 2}H{sub 4} on a single Pd doping atom of Ag clusters is impossible. Display Omitted - Highlights: • H{sub 2} and C{sub 2}H{sub 2} can simultaneously bind with a single Pd doping atom on Ag clusters. • The co-adsorption of H{sub 2} and C{sub 2}H{sub 4} on a single Pd doping atom is impossible. • C{sub 2}H{sub 4} can be hydrogenated to form C{sub 2}H{sub 6} on two neighboring Pd doping atoms. - Abstract: Recently, it has been reported that the reaction selectivity of catalytic hydrogenation of acetylene to ethylene can be significantly enhanced via the approach of Pd mono-atomic catalysis [Pei et al. ACS Catal. 5 (2015) 3717–3725]. To explain the catalytic mechanism of this binary alloy catalyst, C{sub 2}H{sub 2} hydrogenation reactions on Pd doping Ag nanoclusters are studied using density functional theory simulations. The simulation results indicate that H{sub 2} and C{sub 2}H{sub 2} can simultaneously bind with a single Pd doping atom no matter it is on vertex and edge sites of Ag clusters. The following H{sub 2} dissociation and C{sub 2}H{sub 2} hydrogenation are not difficult since the corresponding reaction barrier values are no more than 0.58 eV. The generated C{sub 2}H{sub 4} molecule can not be further hydrogenated since it locates on the top of Pd doping atom, which is the only adsorption site for H{sub 2}. On two Pd doping atoms at contiguous sites of Ag clusters, C{sub 2}H{sub 4} hydrogenation reactions can be carried out since there are enough sites for co-adsorption of H{sub 2} and C{sub 2}H{sub 4}.

  14. In vitro cytotoxicity of Ag-Pd-Cu-based casting alloys.

    Science.gov (United States)

    Niemi, L; Hensten-Pettersen, A

    1985-01-01

    The cytotoxicity and its correlation to alloy composition, structure, corrosion, as well as galvanic coupling was studied with 12 Ag-Pd-Cu-type alloys, one conventional type III gold alloy and pure Ag, Cu, and Pd. The agar overlay cell culture technique was used. Single phase binary CuPd alloys were only slightly cytotoxic below a Cu content of 30 wt%. The tested multiphase alloys were all toxic, but no correlation between toxicity and Cu content could be observed. Solid solution annealing increased the cytotoxicity of a multiphase alloy. Exposure of a single phase alloy to an artificial saliva for 1 week prior to the test decreased its cytotoxicity significantly. Galvanic coupling of the alloys through an outer copper wire decreased their cytotoxicity.

  15. Hollow raspberry-like PdAg alloy nanospheres: High electrocatalytic activity for ethanol oxidation in alkaline media

    Science.gov (United States)

    Peng, Cheng; Hu, Yongli; Liu, Mingrui; Zheng, Yixiong

    2015-03-01

    Palladium-silver (PdAg) alloy nanospheres with unique structure were prepared using a one-pot procedure based on the galvanic replacement reaction. Their electrocatalytic activity for ethanol oxidation in alkaline media was evaluated. The morphology and crystal structure of the samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Electrochemical characterization techniques, including cyclic voltammetry (CV) and chronoamperometry (CA) measurements were used to analyze the electrochemical performance of the PdAg alloy nanospheres. The SEM and TEM images showed that the PdAg alloy nanospheres exhibit a hierarchical nanostructure with hollow interiors and porous walls. Compared to the commercial Pd/C catalyst, the as-prepared PdAg alloy nanospheres exhibit superior electrocatalytic activity and stability towards ethanol electro-oxidation in alkaline media, showing its potential as a new non-Pt electro-catalyst for direct alcohol fuel cells (DAFCs).

  16. Genetic Pd, Pt, Au, Ag, and Rh mineralogy in Noril'sk sulfide ores

    Science.gov (United States)

    Spiridonov, E. M.; Kulagov, E. A.; Serova, A. A.; Kulikova, I. M.; Korotaeva, N. N.; Sereda, E. V.; Tushentsova, I. N.; Belyakov, S. N.; Zhukov, N. N.

    2015-09-01

    The undeformed ore-bearing intrusions of the Noril'sk ore field (NOF) cut through volcanic rocks of the Late Permian-Early Triassic trap association folded in brachysynclines. Due to the nonuniform load on the roof of intrusive bodies, most sulfide melts were squeezed, up to the tops of ore-bearing intrusions; readily fusible Ni-Fe-Cu sulfide melts were almost completely squeezed. In our opinion, not only one but two stages of mineralization developed at the Noril'sk deposits: (i) syntrap magmatic and (ii) epigenetic post-trap metamorphic-hydrothermal. All platinum-group minerals (PGM) and minerals of gold are metasomatic in the Noril'sk ores. They replaced sulfide solid solutions and exsolution structures. All types of PGM and Au minerals occur in the ores, varying in composition from pyrrhotite to chalcopyrite, talnakhite, mooihoekite, and rich in galena; they are localized in the inner and outer contact zones and differ only in the quantitative proportions of ore minerals. The aureoles of PGM and Au-Ag minerals are wider than the contours of sulfide bodies and coincide with halos of fluid impact on orebodies and adjacent host rocks. The pneumatolytic PGM and Au-Ag minerals are correlated in abundance with the dimensions of sulfide bodies. Their amounts are maximal in veins of late fusible ore composed of eutectic PbS ss and iss intergrowths, as well as at their contacts. The Pd and Pt contents in eutectic sulfide ores of NOF are the world's highest. In the process of noble-metal mineral formation, the fluids supply Pd, Pt, Au, As, Sb, Sn, Bi, and a part of Te, whereas Fe, Ni, Cu, Pb, Ag, Rh, a part of Te and Pd are leached from the replaced sulfide minerals. The pneumatolytic PGM of the early stage comprises Pd and Pt intermetallic compounds enriched in Au along with Pd-Pt-Fe-Ni-Cu-Sn-Pb(As) and (Pd,Pt,Au)(Sn,Sb,Bi,Te,As) solid solutions. Pneumatolytic PGM and Au minerals of the middle stage are products of solid-phase transformation and recrystallization of

  17. Capability of defective graphene-supported Pd13 and Ag13 particles for mercury adsorption

    Science.gov (United States)

    Meeprasert, Jittima; Junkaew, Anchalee; Rungnim, Chompoonut; Kunaseth, Manaschai; Kungwan, Nawee; Promarak, Vinich; Namuangruk, Supawadee

    2016-02-01

    Reactivity of single-vacancy defective graphene (DG) and DG-supported Pdn and Agn (n = 1, 13) for mercury (Hg0) adsorption has been studied using density functional theory calculation. The results show that Pdn binds defective site of DG much stronger than the Agn, while metal nanocluster binds DG stronger than single metal atom. Metal clustering affects the adsorption ability of Pd composite while that of Ag is comparatively less. The binding strength of -8.49 eV was found for Pd13 binding on DG surface, indicating its high stability. Analyses of structure, energy, partial density of states, and d-band center (ɛd) revealed that the adsorbed metal atom or cluster enhances the reactivity of DG toward Hg adsorption. In addition, the Hg adsorption ability of Mn-DG composite is found to be related to the ɛd of the deposited Mn, in which the closer ɛd of Mn to the Fermi level correspond to the higher adsorption strength of Hg on Mn-DG composite. The order of Hg adsorption strength on Mn-DG composite are as follows: Pd13 (-1.68 eV) >> Ag13 (-0.67 eV) ∼ Ag1 (-0.69 eV) > Pd1 (-0.62 eV). Pd13-DG composite is therefore more efficient sorbent for Hg0 removal in terms of high stability and high adsorption reactivity compared to the Ag13. Further design of highly efficient carbon based sorbents should be focused on tailoring the ɛd of deposited metals.

  18. Pd-Ag chronology of volatile depletion, crystallization and shock in the Muonionalusta IVA iron meteorite and implications for its parent body

    Science.gov (United States)

    Horan, M. F.; Carlson, R. W.; Blichert-Toft, J.

    2012-10-01

    Muonionalusta, a Group IVA iron meteorite, was analyzed for its 107Pd-107Ag isotope systematics by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) in order to better constrain the initial Solar System abundance of 107Pd and to provide high resolution chronology of the evolution of its parent body. Six metal samples from Muonionalusta yield Ag abundances between 0.1012 and 1.461 ng/g, 107Ag/109Ag between 1.131 and 1.805, with 108Pd/109Ag ratios of 2201 to 52,300. The metal Pd/Ag and Ag isotopic data are correlated with a slope corresponding to a 107Pd/108Pd of (2.15±0.30)×10-5. If the Pd-Ag and Pb-Pb isotope systems closed at the same time in Muonionalusta, i.e., 2-3 Ma after CAI formation, then an initial Solar System ratio of 107Pd/108Pd=(2.8±0.5)×10-5 can be inferred. One troilite sample contains 8.478 ng/g Ag and has a 107Ag/109Ag ratio of 1.0833; its Pd concentration is 205.2 ng/g corresponding to a low 108Pd/109Ag of 13.56. The Pd-Ag results for this troilite plot near the extrapolation of the line passing through the metal points and define an initial 107Ag/109Ag that is substantially higher than chondritic, indicating that Muonionalusta formed from a precursor with high Pd/Ag. Pd and Ag concentrations in Muonionalusta metal suggest fractional crystallization from a source having Pd/Ag>4500, but the initial Ag isotopic composition for Muonionalusta troilite limits the duration of the high Pd/Ag to an interval of ≤0.6 Ma before cooling to closure of the Pd-Ag system. This result suggests that depletion of Ag and other volatile elements occurred shortly before accretion and cooling of the IVA parent body, and may have been associated with violent disruption of a progenitor to the IVA parent. Another troilite sample, its chromite inclusions and adjacent metal were isotopically homogenized locally after 107Pd had decayed, possibly by a later episode of shock >50 Ma after Solar System formation.

  19. Propiedades de aleaciones Ag-Pd para usos odontológicos

    Directory of Open Access Journals (Sweden)

    Basualto, J.

    1996-10-01

    Full Text Available In this search for economically alternative alloys for odontological uses, three complex Ag-Pd alloys, Ag-Pd-Au-Cu type, are studied: two experimental alloys and one commercial product. Chemical and mechanical properties were obtained for these alloys and a comparative analysis of these results was made. The cost, important factor, is established in relation to the materials cost of the commercial product. Vickers hardness values obtained from Ag-Pd alloys with different heat treatments allow to show their versatility in relation to restorative uses and to classify them according to standard practice. Electrochemical and tarnish behavior were obtained that allow to compare the trends. It is concluded that chemical properties are acceptable, when they are compared with odontological alloys of reference. Experimental alloys A1 y A2 were installed in mouth, over a year ago, with satisfactory results until now, which validate previous laboratory predictions.

    En la búsqueda de aleaciones para usos odontológicos, económicamente alternativas, se trabaja con tres aleaciones Ag-Pd complejas, del tipo Ag-Pd-Au-Cu-Otros, dos aleaciones experimentales y un producto comercial. Se determinan las propiedades mecánicas y químicas de estas aleaciones y se hace un análisis comparativo de los resultados. El costo, factor importante, se establece con relación a los materiales del producto comercial. Se determina la dureza Vickers de las aleaciones Ag-Pd con diversos tratamientos térmicos, lo que permite mostrar su versatilidad en cuanto a usos restauradores y clasificarlas según norma. Se determina su comportamiento electroquímico y la resistencia a la pigmentación, lo que permite comparar las tendencias exhibidas. Se concluye que las propiedades químicas son aceptables cuando se compara con aleaciones odontológicas de referencia. Se instalaron en boca aleaciones experimentales A1 y A2, hace más de un año, con resultados satisfactorios hasta

  20. Ion-stimulated Gas Desorption Yields of Electropolished, Chemically Etched, and Coated (Au, Ag, Pd, TiZrV) Stainless Steel Vacuum Chambers and St707 Getter Strips Irradiated with 4.2 MeV/u lead ions

    CERN Document Server

    Mahner, E; Küchler, D; Malabaila, M; Taborelli, M

    2005-01-01

    The ion-induced desorption experiment, installed in the CERN Heavy Ion Accelerator LINAC 3, has been used to measure molecular desorption yields for 4.2 MeV/u lead ions impacting under grazing incidence on different accelerator-type vacuum chambers. Desorption yields for H2, CH4, CO, and CO2, which are of fundamental interest for future accelerator applications, are reported for different stainless steel surface treatments. In order to study the effect of the surface oxide layer on the gas desorption, gold-, silver-, palladium-, and getter-coated 316 LN stainless steel chambers and similarly prepared samples were tested for desorption at LINAC 3 and analysed for chemical composition by X-ray Photoemission Spectroscopy (XPS). The large effective desorption yield of 2 x 104 molecules/Pb53+ ion, previously measured for uncoated, vacuum fired stainless steel, was reduced after noble-metal coating by up to 2 orders of magnitude. In addition, pressure rise measurements, the effectiveness of beam scrubbing with le...

  1. Hollow Ag@Pd core-shell nanotubes as highly active catalysts for the electro-oxidation of formic acid

    DEFF Research Database (Denmark)

    Jiang, Yuanyuan; Lu, Yizhong; Han, Dongxue

    2012-01-01

    by detailed characterizations. The Ag@Pd can significantly improve the electrocatalytic activity towards the electro-oxidation of formic acid and enhance the stability of the Pd component. It is proposed that the enhanced electrochemically active surface area and modulated electron structure of Pd by Ag......Ag nanowires are prepared as templates by a polyol reduction process. Then Ag nanotubes coated with a thin layer of Pd are synthesized through sequential reduction accompanied with the galvanic displacement reaction. The products show a hollow core-shell nanotubular structure, as demonstrated......-shell structure with a hollow interior, which can be applied as high-performance catalysts for the electro-oxidation of formic acid....

  2. Corrosion properties of Ag-Au-Cu-Pd system alloys containing indium.

    Science.gov (United States)

    Hattori, Masayuki; Tokizaki, Teruhiko; Matsumoto, Michihiko; Oda, Yutaka

    2010-01-01

    In this study, the corrosion resistance of Ag-Au-Cu-Pd system alloys consisting of 5 or 10 mass% indium was evaluated. Levels of element release and tarnish were determined and electrochemical measurements performed. Results were compared with those for commercial silver-palladium-gold alloy. In terms of electrochemical behavior, the transpassive potential of these experimental alloys was 168-248mV. Experimental alloys with 25 mass% Au showed similar corrosion resistance to control gold-silver-palladium alloy. Amount of released elements was 14-130microg/cm(2) at 7 days, which is in the allowable range for dental alloys. Addition of indium to Ag-Au-Cu-10mass%Pd system alloys was effective in increasing resistance to tarnish and alloys containing 10 mass% of indium showed a minimal decrease in L(*) values after immersion. These findings indicate that 25Au-37.5Ag-15Cu-10Pd-2Zn-10In-0.5Ir alloy is applicable in dental practice.

  3. Capability of defective graphene-supported Pd{sub 13} and Ag{sub 13} particles for mercury adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Meeprasert, Jittima; Junkaew, Anchalee; Rungnim, Chompoonut; Kunaseth, Manaschai [National Nanotechnology Center, NSTDA, 111 Thailand Science Park, Klong Luang, Pathum Thani 12120 Thailand (Thailand); Kungwan, Nawee [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Promarak, Vinich [School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210 (Thailand); Namuangruk, Supawadee, E-mail: supawadee@nanotec.or.th [National Nanotechnology Center, NSTDA, 111 Thailand Science Park, Klong Luang, Pathum Thani 12120 Thailand (Thailand)

    2016-02-28

    Graphical abstract: Defective graphene (DG) supported Ag{sub 13} and Pd{sub 13} nanoparticles acts as sorbents for elementary mercury (Hg{sup 0}) adsorption. Hg is inert to DG surface, but it moderately adsorbs on deposited Ag{sub 13}-DG and strongly adsorbs on deposited Pd{sub 13}-DG. - Highlights: • Pd{sub 13}-DG composite has highest stability. • Pd{sub 13}-DG composite is the most reactive sorbent for Hg{sup 0} adsorption. • Hg{sup 0} adsorption abilities of Pd-DG composites are relatively higher than those of Ag-DG composites. • The d-band center of deposited metal is an adsorption descriptor of composite models. - Abstract: Reactivity of single-vacancy defective graphene (DG) and DG-supported Pd{sub n} and Ag{sub n} (n = 1, 13) for mercury (Hg{sup 0}) adsorption has been studied using density functional theory calculation. The results show that Pd{sub n} binds defective site of DG much stronger than the Ag{sub n}, while metal nanocluster binds DG stronger than single metal atom. Metal clustering affects the adsorption ability of Pd composite while that of Ag is comparatively less. The binding strength of −8.49 eV was found for Pd{sub 13} binding on DG surface, indicating its high stability. Analyses of structure, energy, partial density of states, and d-band center (ε{sub d}) revealed that the adsorbed metal atom or cluster enhances the reactivity of DG toward Hg adsorption. In addition, the Hg adsorption ability of M{sub n}-DG composite is found to be related to the ε{sub d} of the deposited M{sub n}, in which the closer ε{sub d} of M{sub n} to the Fermi level correspond to the higher adsorption strength of Hg on M{sub n}-DG composite. The order of Hg adsorption strength on M{sub n}-DG composite are as follows: Pd{sub 13} (−1.68 eV) >> Ag{sub 13} (−0.67 eV) ∼ Ag{sub 1} (−0.69 eV) > Pd{sub 1} (−0.62 eV). Pd{sub 13}-DG composite is therefore more efficient sorbent for Hg{sup 0} removal in terms of high stability and high adsorption

  4. Beet juice utilization: Expeditious green synthesis of nobel metal nanoparticles (Ag, Au, Pt, and Pd) using microwaves

    Science.gov (United States)

    Metal nanoparticles of Ag, Au, Pt, and Pd were prepared in aqueous solutions via a rapid microwave-assisted green method using beet juice, an abundant sugar-rich agricultural produce, served as both a reducing and a capping reagent. The Ag nanoparticles with capping prepared by b...

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

    CERN Document Server

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

    2015-01-01

    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. PdAgAu alloy with high resistance to corrosion by H2S

    Energy Technology Data Exchange (ETDEWEB)

    Braun, Fernando [Inst. de Investigaciones en Catalisis y Petroquimica, Santa Fe (Argentina); Miller, James B. [Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Chemical Engineering; National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Gellman, Andrew J. [Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Chemical Engineering; National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Tarditi, Ana M. [Inst. de Investigaciones en Catalisis y Petroquimica, Santa Fe (Argentina); Fleutot, Benoit [Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Chemical Engineering; Kondratyuk, Petro [Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Chemical Engineering; National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Cornaglia, Laura M. [Inst. de Investigaciones en Catalisis y Petroquimica, Santa Fe (Argentina)

    2012-12-01

    PdAgAu alloy films were prepared on porous stainless steel supports by sequential electroless deposition. Two specific compositions, Pd83Ag2Au15 and Pd74Ag14Au12, were studied for their sulfur tolerance. The alloys and a reference Pd foil were exposed to 1000 H2S /H2 at 623 K for periods of 3 and 30 hours. The microstructure, morphology and bulk composition of both nonexposed and H2S-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 H2S exposure. In contrast, the PdAgAu ternary alloys displayed the same FCC structure before and after H2S 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 H2S 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 H2S 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 H2S than pure Pd.

  7. Transparent ITO/Ag-Pd-Cu/ITO multilayer cathode use in inverted organic solar cells

    Directory of Open Access Journals (Sweden)

    Hyo-Joong Kim

    2015-10-01

    Full Text Available The characteristics of transparent ITO/Ag-Pd-Cu (APC/ITO multilayer cathodes were investigated for use in inverted organic solar cells (IOSCs. The insertion of an APC interlayer into the ITO film effectively led to crystallization of the top ITO layer, unlike that in the Ag interlayer, and resulted in a low sheet resistance of 6.55 Ohm/square and a high optical transmittance of 84.14% without post annealing. In addition, the alloying of the Pd and Cu elements into Ag prevented agglomeration and oxidization of the metal interlayer and led to more stable ITO/APC/ITO films under ambient conditions. The microstructure and interfacial structure of the transparent ITO/APC/ITO cathode in the IOSCs were examined in detail by synchrotron X-ray scattering and high resolution transmission electron microscopy. Furthermore, we suggested a possible mechanism to explain the lower PCE of the IOSCs with an ITO/APC/ITO cathode than that of a reference IOSC with a crystalline ITO cathode using the external quantum efficiency of the IOSCs.

  8. Synthesis and characterization of PdAg as a catalyst for oxygen reduction reaction in acid medium; Sintesis y caracterizacion de PdAg como catalizador para la reaccion de reduccion de oxigeno en medio acido

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Casillas, D. C.; Vazquez-Huerta, G.; Solorza-Feria, O. [Centro de Investigacion y de Estudios Avanzados del IPN, Mexico D.F. (Mexico)]. E-mail: dcmartinez@cinvestav.mx

    2009-09-15

    This work presents the synthesis of the binary compound PdAg and the electrochemical characterization for oxygen reduction reaction (ORR) in acid medium. The catalyst is obtained from the reduction of Pd(NO{sub 3}){sub 2}·2H{sub 2}O and AgNO{sub 3} with NaBH{sub 4} in THF. The synthesized compound was physically characterized with transmission electron microscopy (TEM), sweep electron microscopy (SEM) and x-ray diffraction (XRD) of powder. Electrochemical studies were conducted to determine the catalytic activity and intrinsic properties of the PdAg material for the ORR in acid medium using cyclic voltamperometry (CV), rotary disc electrode (RDE) and electrochemical impedance spectroscopy (EIS) in a solution of H{sub 2}SO{sub 4} 0.5 M at 25 degrees Celsius. The electrochemical current-potential responses were compared to those of palladium and platinum. The kinetic results showed an increase in the performance of the bimetallic electrocatalyst containing Ag as compared to pure Pd, but less than that obtained with nanometric Pt. The Tafel slopes obtained are roughly120 mV dec-1, similar to that reported for Pt and Pd and for other Ru-based electrocatalysts. [Spanish] En este trabajo se presentan la sintesis del compuesto binario PdAg y su caracterizacion electroquimica para la reaccion de reduccion de oxigeno (RRO) en medio acido. El catalizador se obtuvo a partir de la reduccion de Pd(NO{sub 3}){sub 2}·2H{sub 2}O y AgNO{sub 3} con NaBH{sub 4} en THF. El compuesto sintetizado se caracterizo fisicamente por microscopia electronica de transmision (MET), microscopia electronica de barrido (MEB) y difraccion de rayos X (DRX) de polvos. Se realizaron estudios electroquimicos para determinar la actividad catalitica y las propiedades intrinsecas del material de PdAg para la reaccion de reduccion de oxigeno (RRO) en medio acido, utilizando las tecnicas de voltamperometria ciclica (VC), electrodo disco rotatorio (EDR) y espectroscopia de impedancia electroquimica (EIE), en

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

    Science.gov (United States)

    Poudel, L.; de la Cruz, C.; Payzant, E. A.; May, A. F.; Koehler, M.; Garlea, V. O.; Taylor, A. E.; Parker, D. S.; Cao, H. B.; McGuire, M. A.; Tian, W.; Matsuda, M.; Jeen, H.; Lee, H. N.; Hong, T.; Calder, S.; Zhou, H. D.; Lumsden, M. D.; Keppens, V.; Mandrus, D.; Christianson, A. D.

    2015-12-01

    The structural and the magnetic properties of CeCu6 -xAgx (0 ≤x ≤0.85 ) and CeCu6 -xPdx (0 ≤x ≤0.4 ) have been studied using neutron diffraction, resonant ultrasound spectroscopy (RUS), x-ray diffraction measurements, and first principles calculations. The structural and magnetic phase diagrams of CeCu6 -xAgx and CeCu6 -xPdx as a function of Ag/Pd composition are reported. The end member, CeCu6, undergoes a structural phase transition from an orthorhombic (P n m a ) to a monoclinic (P 21/c ) phase at 240 K. In CeCu6 -xAgx , the structural phase transition temperature (Ts) decreases linearly with Ag concentration and extrapolates to zero at xS ≈0.1 . The structural transition in CeCu6 -xPdx remains unperturbed with Pd substitution within the range of our study. The lattice constant b slightly decreases with Ag/Pd doping, whereas a and c increase with an overall increase in the unit cell volume. Both systems, CeCu6 -xAgx and CeCu6 -xPdx , exhibit a magnetic quantum critical point (QCP), at x ≈0.2 and x ≈0.05 , respectively. Near the QCP, long range antiferromagnetic ordering takes place at an incommensurate wave vector (δ10 δ2), where δ1˜0.62 ,δ2˜0.25 ,x =0.125 for CeCu6 -xPdx and δ1˜0.64 ,δ2˜0.3 ,x =0.3 for CeCu6 -xAgx . The magnetic structure consists of an amplitude modulation of the Ce moments which are aligned along the c axis of the orthorhombic unit cell.

  10. Mechanical properties and microstructural analysis of an AgPd alloy cast under different temperatures

    OpenAIRE

    Olivieri, Karina Andrea Novaes; Faculdade de Odontologia de São José dos Campos - UNESP; Neisser, Maximiliano Piero; Bottino, Marco Antônio; Milton Edson MIRANDA; Wernek, Rafael Dario

    2010-01-01

    The metal restorations are used in Dentistry a long time ago. Nowadays we have resources that can get casting more accurate, with new material and equipments and techniques more precise. The purpose of this study was to evaluate the metallurgical and mechanical aspects of the AgPd dental alloy when it was submitted to different casting temperatures. It was used 30 specimens, divided in three groups (n=10): a) control group (no cast); b) casting temperature in accordance wi...

  11. Mechanism of unique hardening of dental Ag-Pd-Au-Cu alloys in relation with constitutional phases

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yonghwan [Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6 Aoba, Aramaki Aza, Aoba-ku, Sendai 980-8579 (Japan); Niinomi, Mitsuo, E-mail: niinomi@imr.tohoku.ac.jp [Department of Biomaterials Science, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Nakai, Masaaki; Akahori, Toshikazu [Department of Biomaterials Science, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Kanno, Toru [Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6 Aoba, Aramaki Aza, Aoba-ku, Sendai 980-8579 (Japan); Fukui, Hisao [Department of Dental Materials Science, School of Dentistry, Aichi-Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650 (Japan)

    2012-04-05

    Highlights: Black-Right-Pointing-Pointer The unique hardening behavior on Ag-Pd-Au-Cu alloys by solution treatment was investigated. Black-Right-Pointing-Pointer The Cu-rich {alpha}{sub 1} phase and Ag-rich {alpha}{sub 2} phase decomposed by solution treatment contributed weakly to the change of hardness. Black-Right-Pointing-Pointer The fine {beta} phases precipitated by aging treatment caused great increase in hardness. Black-Right-Pointing-Pointer The fine L1{sub 0}-type ordered {beta} Prime phase precipitated by solution treatment may contribute to the unique hardening behavior. - Abstract: The objective of this research was to investigate the effect of constitutional phases on the unique hardening behavior of as-solutionized dental Ag-Pd-Au-Cu alloy fabricated by cold rolling. The commercial dental Ag-Pd-Au-Cu alloy fabricated by cold rolling consists of Cu-rich {alpha}{sub 1}, Ag-rich {alpha}{sub 2}, and {beta} phases. On the other hand, the Ag-Pd-Au-Cu alloy fabricated by the liquid rapid solidification (LRS) method consists of single {alpha} phase. They were subjected to various heat treatments, respectively. The microstructures were observed by scanning electron microscope, transmission electron microscope and X-ray diffraction. The hardness was evaluated by a Vickers micro-hardness tester. In the Ag-Pd-Au-Cu alloy fabricated by cold rolling, the fine L1{sub 0}-type-ordered {beta} Prime phase is precipitated and the coarse {beta} phase is remained after solution treatment at 1123 K. The hardness increases drastically. On the other hand, in the Ag-Pd-Au-Cu alloy fabricated by LRS method, the single {alpha} phase was decomposed into the {alpha}{sub 1} phase and the {alpha}{sub 2} phase after solution treatment at 1023 K and its hardness change was small. However, after aging treatment at 673 K, the fine {beta} phase is precipitated in the {alpha} phase and the hardness increases greatly even in the Ag-Pd-Au-Cu alloy fabricated by LRS method. It is considered

  12. Change of Work Function of Pd, Ag, K on Al(001) as a Function of External Electric Field

    Institute of Scientific and Technical Information of China (English)

    侯柱峰; 黄美纯; 朱梓忠; 黄荣彬; 郑兰荪

    2001-01-01

    We present a local density functional calculation of the effect of an external electric field on the work function change of Pd and Ag adsorption on an Al(001) surface. The adsorption of K has also been considered for comparison. We found that the work functions for all the systems increased linearly when the strength of the external electric field was increased. Since the polarized electrons at the interstitial regions between the adsorbate and substrate for Pd/Al(001) and Ag/Al(001) react to the external electric field differently, the subtle differences between Pd/Al(001) and Ag/Al(001) bondings has been characterized through the comparison of the slopes of the work function change versus electric field.

  13. Electromotive force measurements in liquid Ag-In-Pd lead-free alloys

    Institute of Scientific and Technical Information of China (English)

    Grzegorz Garzel; Leszek A. Zabdyr

    2006-01-01

    Emf technique was employed to determine indium activities in the liquid Ag-In-Pd alloys using galvanic cellswith yttria-stabilised-zirconia as solid electrolyte according to the scheme: kanthal/rhenium, Ag-In-Pd, In2O3 | YSZ | Ni, NiO, Pt. Composition and temperature measurement ranges were limited, because of very steep liquidus surface; 35 compositions for XPd up to 0.3 were investigated and at temperatures from near-liquidus up to 1700 K. High temperature experiments required special moly furnace to be constructed with unique automatic gas supply system for furnace winding protective atmosphere. Emf readings were taken and recorded by automatic data acquisition system. Linear dependence of emf on temperature was observed for all compositions investigated, and results were approximated by straight line equations. Then In activities were calculated using well-known relations and taking into account correction for thermoelectric power between kanthal and platinum. Results are to be used along with other existing data to perform assessment of the ternary system under accord.

  14. Compensation effect in H 2 permeation kinetics of PdAg membranes

    KAUST Repository

    Zeng, Gaofeng

    2012-08-30

    Knowledge about the (inter)dependence of permeation kinetic parameters on the stoichiometry of H 2-selective alloys is still rudimentary, although uncovering the underlying systematic correlations will greatly facilitate current efforts into the design of novel high-performance H 2 separation membranes. Permeation measurements with carefully engineered, 2-7 μm thick supported Pd 100-xAg x membranes reveal that the activation energy and pre-exponential factor of H 2 permeation laws vary systematically with alloy composition, and both kinetic parameters are strongly correlated for x ≤ 50. We show that this permeation kinetic compensation effect corresponds well with similar correlations in the hydrogen solution thermodynamics and diffusion kinetics of PdAg alloys that govern H 2 permeation rates. This effect enables the consistent description of permeation characteristics over wide temperature and alloy stoichiometry ranges, whereas hydrogen solution thermodynamics may play a role, too, as a yet unrecognized source of kinetic compensation in, for example, H 2-involving reactions over metal catalysts or hydrogenation/ dehydrogenation of hydrogen storage materials. © 2012 American Chemical Society.

  15. 分子动力学模拟Au-Pd和Ag-Pt合金的热学和力学性质%Thermal and Mechanical Properties of Au-Pd and Ag-Pt Alloy by Molecular Dynamics Simulation

    Institute of Scientific and Technical Information of China (English)

    闫雪松; 齐新; 林平; 杨磊

    2011-01-01

    利用Finnis-Sinclair势,对金属Au、Pd、Ag、Pt和合金Au3Pd、AuPd3、Ag3Pt、AgPt3的热学和力学性质进行了分子动力学模拟.首次计算了不同温度下合金的晶格常数、结合能和弹性常数,并预测了它们的熔点.通过比较发现,Au3Pd、AuPd3和Ag3Pt这3种合金的晶格常数、结合能和弹性常数介于其组分金属之间,而AgPt3的剪切模量和熔点高于其组分hg和Pt.%With the Finnis-Sinclair potential, the thermal and mechanical properties of Au, Pd, Ag, Pt pure metals and their alloys Au3Pd, AuPd3, Ag3Pt, AgPt3 were studied by molecular dynamics simulations. Lattice constants and elastic constants of Au3Pd, AuPd3, Ag3Pt and AgPt3 at different temperatures were predicted for the first time. Melting temperatures of these alloys were calculated too. Furthermore, lattice constants, elastic constants and melting temperature of pure metals Au, Pd, Ag, and Pt were calculated for comparison. It is found that for Au3Pd,AuPd3 and Ag3Pt, lattice constants, elastic constants and melting temperatures lie between those of their two components. For AgPt3, the values of shear modulus and melting temperature are higher than those for both Ag and Pt pure metals.

  16. Calculation of Elastic Constants of Ag/Pd Superlattice Thin Films by Molecular Dynamics with Many-Body Potentials

    Institute of Scientific and Technical Information of China (English)

    GAO Ning; LAI Wen-Sheng

    2006-01-01

    @@ The calculation of elastic constants of Ag/Pd superlattice thin films by molecular dynamics simulations with many-body potentials is presented. It reveals that the elastic constants C11 and C55 increase with decreasing modulation wavelength A of the films, which is consistent with experiments. However, the change of C11 and C55 with A is found to be around the values determined by a rule of mixture using bulk elastic constants of metals.No supermodulus effect is observed and it is due to cancellation between enhanced and reduced contributions to elastic constants from Ag and Pd layers subjected to compressive and tensile strains, respectively.

  17. Green Synthesis of Ag and Pd Nanospheres, Nanowires, and Nanorods Using Vitamin B2: Catalytic Polymerisation of Aniline and Pyrrole

    Science.gov (United States)

    For the first time, we report green chemistry approach using vitamin B2 in the synthesis of silver (Ag) and palladium (Pd), nanospheres, nanowires and nanorods at room temperature without using any harmful reducing agents, such as sodium borohydride (NaBH4) or hydroxylamine hydro...

  18. A green approach to ethyl acetate: Quantitative conversion of ethanol through direct dehydrogenation in a Pd-Ag membrane reactor

    KAUST Repository

    Zeng, Gaofeng

    2012-11-07

    Pincers do the trick: The conversion of ethanol to ethyl acetate and hydrogen was achieved using a pincer-Ru catalyst in a Pd-Ag membrane reactor. Near quantitative conversions and yields could be achieved without the need for acid or base promoters or hydrogen acceptors (see scheme). © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Effect of Ag and Pd promotion on CH4 selectivity in Fe(100) Fischer-Tröpsch catalysis.

    Science.gov (United States)

    Psarras, Peter C; Wilcox, Jennifer; Ball, David W

    2017-02-15

    The current CO2 utilization market is dominated by enhanced oil recovery and urea manufacturing; yet, the scale of demand falls well short of that deemed necessary to make a significant impact on climate change. CO2 conversion to fuels, however, is a utilization technology that can theoretically match the scale of projected CO2 capture. Fischer-Tröpsch (FT) processing is a long-established technology for converting non-petroleum based precursors into transportation fuels and other valuable chemicals. Here, we report the effects of Pd and Ag doping on CH4 selectivity over Fe(100), a common FT catalyst, as these metals have shown potential in the direct conversion of co-fed CO2. Adsorption energies for pathway specific C1 and C2 species were weakened in the presence of Ag and Pd by ca. 0.55 eV and 0.35 eV, respectively. Further, while both Ag- and Pd-promoted surfaces show decreased CH4 production, Ag introduces a prohibitively high coupling barrier; thus, only Pd offered a decrease in CH4 selectivity (-36%) relative to unmodified Fe(100).

  20. The adhesion performance of epoxy coating on AA6063 treated in Ti/Zr/V based solution

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Wen; Li, Wenfang, E-mail: mewfli@scut.edu.cn; Mu, Songlin; Yang, Yunyu; Zuo, Xi

    2016-10-30

    Highlights: • A non-chrome titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating is prepared on AA6063 at room temperature. • The Ti/Zr/V conversion coating is produced on AA6063 within 50 s. • The adhesion strength between epoxy coating and AA6063 is improved significantly after the Ti/Zr/V conversion treatment. - Abstract: An environment-friendly titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating was prepared on aluminum alloy 6063 (AA6063). The epoxy powder coatings were applied on the AA6063 samples with/without Ti/Zr/V conversion coatings via electrostatic spraying. The morphology and composition of the conversion coating were studied by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The surface free energy components of AA6063 samples were measured by a static contact angle measuring device with Owens method. The adhesion properties of the epoxy coating on AA6063 treated with different conversion times were evaluated using a pull-off tester. The Ti/Zr/V conversion coating was mainly composed of metal oxide (TiO{sub 2}, ZrO{sub 2}, V{sub 2}O{sub 5}, Al{sub 2}O{sub 3}, etc.), metal fluoride (ZrF{sub 4}, AlF{sub 3}, etc.) and metal organic complex. The formation time of this conversion coating was reduced to 50 s. After such surface treatment, the samples' surface roughness was increased and the contact angle with water was decreased. Both the surface free energy and the work of adhesion were increased. The adhesion strength between the epoxy coating and AA6063 was enhanced significantly.

  1. Ti/Pd/Ag Contacts to n-Type GaAs for High Current Density Devices

    Science.gov (United States)

    Huo, Pengyun; Rey-Stolle, Ignacio

    2016-06-01

    The metallization stack Ti/Pd/Ag on n-type Si has been readily used in solar cells due to its low metal/semiconductor specific contact resistance, very high sheet conductance, bondability, long-term durability, and cost-effectiveness. In this study, the use of Ti/Pd/Ag metallization on n-type GaAs is examined, targeting electronic devices that need to handle high current densities and with grid-like contacts with limited surface coverage (i.e., solar cells, lasers, or light emitting diodes). Ti/Pd/Ag (50 nm/50 nm/1000 nm) metal layers were deposited on n-type GaAs by electron beam evaporation and the contact quality was assessed for different doping levels (from 1.3 × 1018 cm-3 to 1.6 × 1019 cm-3) and annealing temperatures (from 300°C to 750°C). The metal/semiconductor specific contact resistance, metal resistivity, and the morphology of the contacts were studied. The results show that samples doped in the range of 1018 cm-3 had Schottky-like I- V characteristics and only samples doped 1.6 × 1019 cm-3 exhibited ohmic behavior even before annealing. For the ohmic contacts, increasing annealing temperature causes a decrease in the specific contact resistance ( ρ c,Ti/Pd/Ag ~ 5 × 10-4 Ω cm2). In regard to the metal resistivity, Ti/Pd/Ag metallization presents a very good metal conductivity for samples treated below 500°C ( ρ M,Ti/Pd/Ag ~ 2.3 × 10-6 Ω cm); however, for samples treated at 750°C, metal resistivity is strongly degraded due to morphological degradation and contamination in the silver overlayer. As compared to the classic AuGe/Ni/Au metal system, the Ti/Pd/Ag system shows higher metal/semiconductor specific contact resistance and one order of magnitude lower metal resistivity.

  2. Green Synthesis of Ag and Pd Nanospheres, Nanowires, and Nanorods Using Vitamin B2: Catalytic Polymerisation of Aniline and Pyrrole

    Directory of Open Access Journals (Sweden)

    Mallikarjuna N. Nadagouda

    2008-01-01

    Full Text Available For the first time, we report green chemistry approach using vitamin B2 in the synthesis of silver (Ag and palladium (Pd, nanospheres, nanowires, and nanorods at room temperature without using any harmful reducing agents, such as sodium borohydride (NaBH4 or hydroxylamine hydrochloride and any special capping or dispersing agent. Vitamin B2 was used as reducing agent as well as capping agent due to its high-water solubility, biodegradability, and low-toxicity compared with other reducing agents. The average particle size of nanoprticle was found to be Ag (average size 6.1±0.1 nm and Pd (average size 4.1±0.1 nm nanoparticles in ethylene glycol and Ag (average size 5.9±0.1 nm, and average size 6.1±0.1 nanoparticles in acetic acid and NMP, respectively. The formation of noble multiple shape nanostructures and their self assembly were dependent on the solvent employed for the preparation. When water was used as solvent media, Ag and Pd nanoparticles started to self-assemble into rod-like structures and in isopropanol Ag and Pd nanoparticles yielded wire-like structures with a thickness in the range of 10 to 20 nm and several hundred microns in length. In acetone and acetonitrile medium, the Ag and Pd nanoparticles are self-assembled into a regular pattern making nanorod structures with thicknesses ranging from 100 to 200 nm and lengths of a few microns. The so-synthesized nanostructures were characterized using scanning electron microscopy (SEM, transmission electron microscopy (TEM, energy dispersive X-ray (EDX analysis, and UV spectroscopy. The ensuing Ag and Pd nanoparticles catalyzed the reactions of aniline and pyrrole to generate polyaniline and polypyrrole nanofibers and may find various technological and biological applications. This single-step greener approach is general and can be extended to other noble metals and transition metal oxides.

  3. Lowering the activation temperature of TiZrV non-evaporable getter films [for LHC

    CERN Document Server

    Prodromides, A E; Taborelli, M

    2001-01-01

    In order to reduce the activation temperature of the TiZrV alloy, thin films of various compositions were produced by three-cathode magnetron sputtering on stainless-steel substrates. For the characterisation of the activation behaviour the surface chemical composition has been monitored by Auger electron spectroscopy during specific in situ thermal cycles. The volume elemental composition of the film has been measured by energy dispersive X-ray spectroscopy and the morphology (crystal structure and size of the crystallites) has been investigated by X-ray diffraction. The criteria indicating the sample quality and its dependence on film structure and chemical composition are presented and discussed. (13 refs).

  4. Lowering the activation temperature of TiZrV non-evaporable getter films

    CERN Document Server

    Taborelli, M; Scheuerlein, C

    1999-01-01

    In order to reduce the activation temperature of the TiZrV alloy, thin films of various compositions were produced by three-cathode magnetron sputtering on stainless steel substrates. For the characterisation of the activation behaviour the surface chemical composition has been monitored by Auger Electron Spectroscopy (AES) during specific in situ thermal cycles. The volume elemental composition of the film has been measured by Energy Dispersive X-ray spectroscopy (EDX) and the morphology (crystal structure and size of the crystallites) has been investigated by X-ray diffraction (XRD). The criteria indicating the sample quality and its dependence on film structure and chemical composition are presented and discussed.

  5. Ag/Pd纳米复合自组装膜的制备与电催化性质%Preparation of Ag/Pd Nanocomposite Thin Films by Layer-by-Layer Assembly Technique and Their Electrocatalytic Properties

    Institute of Scientific and Technical Information of China (English)

    张莉; 王聪; 王红艳; 张超

    2012-01-01

    利用层层静电自组装技术将聚乙烯亚胺(PEI-Ag+)、PdCl42-交替沉积在基底上,然后用硼氢化钠还原,构筑了含银/钯复合纳米粒子的PEI-Ag/Pd纳米复合薄膜.通过扫描电子显微镜(FESEM),X射线光电子能谱(XPS)和循环伏安(CV)等手段对复合膜的成分、微结构和性质进行了测试分析.膜上生成了不规则和立方体状的银/钯纳米复合物,导致膜表面有一定的粗糙度.结果表明,双金属{PEI-Ag/Pd}n复合膜比单金属{PEI/Pd}n或{PEI-Ag/PSS}n膜对多巴胺的氧化有更好的电催化活性.%Nanocomposite thin films containing Ag/Pd nanoparticles PEI-Ag/Pd were formed by alternating adsorption of PEI-Ag+ and PdCl42- by a layer-by-layer self-assembly technique and subsequent postdeposition reduction by sodium borohydride (NaBH4). The composition, microstructure and properties were characterized by field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV). The Ag/Pd nanocomposites which are irregular and cubic are formed in the films, resulting in a rough surface of the composite film. The results indicate that the {PEI-Ag/Pd}n nanocomposite film exhibits better electrocatalytic activity for the oxidation of dopamine than {PEI/Pd}n and {PEI-Ag/PSS}n films.

  6. Leaching of Au, Ag, and Pd from waste printed circuit boards of mobile phone by iodide lixiviant after supercritical water pre-treatment

    Energy Technology Data Exchange (ETDEWEB)

    Xiu, Fu-Rong, E-mail: xiu_chem@hotmail.com [College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350108 (China); Qi, Yingying [College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350108 (China); Zhang, Fu-Shen [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

    2015-07-15

    Highlights: • We report a novel process for recovering Au, Ag, and Pd from waste PCBs. • The effect of SCWO on the leaching of Au, Ag, and Pd in waste PCBs was studied. • SCWO was highly efficient for enhancing the leaching of Au, Ag, and Pd. • The optimum leaching parameters for Au, Ag, and Pd in iodine–iodide were studied. - Abstract: Precious metals are the most attractive resources in waste printed circuit boards (PCBs) of mobile phones. In this work, an alternative process for recovering Au, Ag, and Pd from waste PCBs of mobile phones by supercritical water oxidation (SCWO) pre-treatment combined with iodine–iodide leaching process was developed. In the process, the waste PCBs of mobile phones were pre-treated in supercritical water, then a diluted hydrochloric acid leaching (HL) process was used to recovery the Cu, whose leaching efficiency was approximately 100%, finally the resulting residue was subjected to the iodine–iodide leaching process for recovering the Au, Ag, and Pd. Experimental results indicated that SCWO pre-treatment temperature, time, and pressure had significant influence on the Au, Ag, and Pd leaching from (SCWO + HL)-treated waste PCBs. The optimal SCWO pre-treatment conditions were 420 °C and 60 min for Au and Pd, and 410 °C and 30 min for Ag. The optimum dissolution parameters for Au, Pd, and Ag in (SCWO + HL)-treated PCBs with iodine–iodide system were leaching time of 120 min (90 min for Ag), iodine/iodide mole ratio of 1:5 (1:6 for Ag), solid-to-liquid ratio (S/L) of 1:10 g/mL (1:8 g/mL for Ag), and pH of 9, respectively. It is believed that the process developed in this study is environment friendly for the recovery of Au, Ag, and Pd from waste PCBs of mobile phones by SCWO pre-treatment combined with iodine–iodide leaching process.

  7. Mass Spectrometric Studies on Metai-hexafluorobenzene Anionic Comolexes(M=Ag,Au,Pd,Pt,Pb and Bi)

    Institute of Scientific and Technical Information of China (English)

    SUN Zhang; SUN Shu-tao; LIU Hong-tao; ZHU Qi-he; GAO Zhen; TANG Zi-chao

    2009-01-01

    The anionic products from the reactions between metal(M=Ag,Au,Pd,Pt,Pb and Bi) vapour produced by laser ablation and hexafluorobenzene seeded in carrier gas(Ar) were studied by means of a homemade reflectron time-of-flight mass spectrometry(RTOF-MS).Experimental results show that the dominant products were [MmC6F6]-complexes for the reactions of Ag,Au,Pd and Pt with C6F6,while the dominant products were [MmC6Fs]- complexes for the reactions of Pb and Bi with C6F6.The formation mechanisms of the products,including the adsorption of metal cluster anions on hexafluorobenzene and the C-F cleavage induced by metal cluster anions,were discussed.

  8. Ultra-small Tetrametallic Pt-Pd-Rh-Ag Nanoframes with Tunable Behavior for Direct Formic Acid/Methanol Oxidation.

    Science.gov (United States)

    Saleem, Faisal; Ni, Bing; Yong, Yang; Gu, Lin; Wang, Xun

    2016-10-01

    Reversible tuning of ultra-small multimetallic Pt-Pd-Rh-Ag nanoframes is achieved. These nanoframes showed tunable and reversible modes for the oxidation of small organic molecules by simply inducing segregation with adsorbates, such as SO4(2-) and OH(-) . This is the first example of reversible segregation under electrocatalytic conditions in atomic-sized electrocatalysts. These nanoframes also showed a controllable activity and good stability for the oxidation of small organic molecules.

  9. Vibrational states on vicinal surfaces of Al, Ag, Cu and Pd

    Science.gov (United States)

    Sklyadneva, I. Yu.; Rusina, G. G.; Chulkov, E. V.

    1998-10-01

    We present the calculation of vibrational modes and lattice relaxation for the (110), (211), (311), (511), (331) and (221) surfaces of Al, Ag, Cu and Pd. The surface phonon frequencies and polarizations are obtained for relaxed and unrelaxed surfaces using embedded atom model potentials. On all surfaces studied step-localized vibrational modes and surface states localized on terrace atoms are found. It is shown that as the terrace width increases so does the number of surface phonons. It is found that interlayer relaxation leads to a shift in the frequencies of the surface states and to a change in the number and localization. In particular, it may cause the appearance or disappearance of step modes. It is shown that the character of relaxation on vicinal surfaces is determined by the number of atoms on a terrace. A comparison of the results with the available experimental data for the Al(221), Cu(211), and Cu(511) surfaces indicates that there is a good agreement with the experimental data.

  10. Effect of thione primers on adhesive bonding between an indirect composite material and Ag-Pd-Cu-Au alloy.

    Science.gov (United States)

    Imai, Hideyuki; Koizumi, Hiroyasu; Shimoe, Saiji; Hirata, Isao; Matsumura, Hideo; Nikawa, Hiroki

    2014-01-01

    The current study evaluated the effect of primers on the shear bond strength of an indirect composite material joined to a silverpalladium-copper-gold (Ag-Pd-Cu-Au) alloy (Castwell). Disk specimens were cast from the alloy and were air-abraded with alumina. Eight metal primers were applied to the alloy surface. A light-polymerized indirect composite material (Solidex) was bonded to the alloy. Shear bond strength was determined both before and after the application of thermocycling. Two groups primed with Metaltite (thione) and M. L. Primer (sulfide) showed the greatest post-thermocycling bond strength (8.8 and 6.5 MPa). The results of the X-ray photoelectron spectroscopic (XPS) analysis suggested that the thione monomer (MTU-6) in the Metaltite primer was strongly adsorbed onto the Ag-Pd-Cu-Au alloy surface even after repeated cleaning with acetone. The application of either the thione (MTU-6) or sulfide primer is effective for enhancing the bonding between a composite material and Ag-Pd-Cu-Au alloy.

  11. Study on deposition technique and properties of Pd/Ag alloy film sensor supported on ceramic substrate

    Science.gov (United States)

    Geng, Z. T.; He, Q.; Jin, C. G.

    2016-07-01

    Developing high-quality hydrogen sensitive material is the core part of hydrogen sensor, whose performance is determined by the sensitive response, reproducibility and recovery of hydrogen material etc. In order to overcome the defects of hydrogen embrittlement in previous hydrogen sensor which were based on the pure palladium, sliver as the second component added to the palladium was studied. Using photochemical etching technology to produce a bent metal mask, the mask is put on the ceramic substrate. Firstly, the thin film of Ta2O5 as a transition layer grew on the ceramic substrate. Then, a series of Pd/Ag alloy film sensors were prepared, and each performance characterization of Pd/Ag alloy film was studied. Testing results indicated that the thin film had a good linear output performance at 0∼⃒30% hydrogen concentration range, and demonstrates a high responsiveness and good repeatability. With temperature increasing, the strength of the responsive signal of the Pd/Ag alloy film decreases and its responsive time was also shortened.

  12. Mixed Phytochemicals Mediated Synthesis of Multifunctional Ag-Au-Pd Nanoparticles for Glucose Oxidation and Antimicrobial Applications.

    Science.gov (United States)

    Rao, K Jagajjanani; Paria, Santanu

    2015-07-01

    The growing awareness toward the environment is increasing commercial demand for nanoparticles by green route syntheses. In this study, alloy-like Ag-Au-Pd trimetallic nanoparticles have been prepared by two plants extracts Aegle marmelos leaf (LE) and Syzygium aromaticum bud extracts (CE). Compositionally different Ag-Au-Pd nanoparticles with an atomic ratio of 5.26:2.16:1.0 (by LE) and 11.36:13.14:1.0 (by LE + CE) of Ag:Au:Pd were easily synthesized within 10 min at ambient conditions by changing the composition of phytochemicals. The average diameters of the nanoparticles by LE and LE + CE are ∼8 and ∼11 nm. The catalytic activity of the trimetallic nanoparticles was studied, and they were found to be efficient catalysts for the glucose oxidation process. The prepared nanoparticles also exhibited efficient antibacterial activity against a model Gram-negative bacteria Escherichia coli. The catalytic and antimicrobial properties of these readymade trimetallic nanoparticles have high possibility to be utilized in diverse fields of applications such as health care to environmental.

  13. Determination of the compositions of the DIGM zone in nanocrystalline Ag/Au and Ag/Pd thin films by secondary neutral mass spectrometry

    Directory of Open Access Journals (Sweden)

    Gábor Y. Molnár

    2016-03-01

    Full Text Available Alloying by grain boundary diffusion-induced grain boundary migration is investigated by secondary neutral mass spectrometry depth profiling in Ag/Au and Ag/Pd nanocrystalline thin film systems. It is shown that the compositions in zones left behind the moving boundaries can be determined by this technique if the process takes place at low temperatures where solely the grain boundary transport is the contributing mechanism and the gain size is less than the half of the grain boundary migration distance. The results in Ag/Au system are in good accordance with the predictions given by the step mechanism of grain boundary migration, i.e., the saturation compositions are higher in the slower component (i.e., in Au or Pd. It is shown that the homogenization process stops after reaching the saturation values and further intermixing can take place only if fresh samples with initial compositions, according to the saturation values, are produced and heat treated at the same temperature. The reversal of the film sequence resulted in the reversal of the inequality of the compositions in the alloyed zones, which is in contrast to the above theoretical model, and explained by possible effects of the stress gradients developed by the diffusion processes itself.

  14. Leaching of Au, Ag, and Pd from waste printed circuit boards of mobile phone by iodide lixiviant after supercritical water pre-treatment.

    Science.gov (United States)

    Xiu, Fu-Rong; Qi, Yingying; Zhang, Fu-Shen

    2015-07-01

    Precious metals are the most attractive resources in waste printed circuit boards (PCBs) of mobile phones. In this work, an alternative process for recovering Au, Ag, and Pd from waste PCBs of mobile phones by supercritical water oxidation (SCWO) pre-treatment combined with iodine-iodide leaching process was developed. In the process, the waste PCBs of mobile phones were pre-treated in supercritical water, then a diluted hydrochloric acid leaching (HL) process was used to recovery the Cu, whose leaching efficiency was approximately 100%, finally the resulting residue was subjected to the iodine-iodide leaching process for recovering the Au, Ag, and Pd. Experimental results indicated that SCWO pre-treatment temperature, time, and pressure had significant influence on the Au, Ag, and Pd leaching from (SCWO+HL)-treated waste PCBs. The optimal SCWO pre-treatment conditions were 420°C and 60min for Au and Pd, and 410°C and 30min for Ag. The optimum dissolution parameters for Au, Pd, and Ag in (SCWO+HL)-treated PCBs with iodine-iodide system were leaching time of 120min (90min for Ag), iodine/iodide mole ratio of 1:5 (1:6 for Ag), solid-to-liquid ratio (S/L) of 1:10g/mL (1:8g/mL for Ag), and pH of 9, respectively. It is believed that the process developed in this study is environment friendly for the recovery of Au, Ag, and Pd from waste PCBs of mobile phones by SCWO pre-treatment combined with iodine-iodide leaching process.

  15. DFT study of Hg adsorption on M-substituted Pd(1 1 1) and PdM/γ-Al2O3(1 1 0) (M = Au, Ag, Cu) surfaces

    Science.gov (United States)

    Wang, Jiancheng; Yu, Huafeng; Geng, Lu; Liu, Jianwen; Han, Lina; Chang, Liping; Feng, Gang; Ling, Lixia

    2015-11-01

    The adsorption of Hgn (n = 1-3) on the Au-, Ag-, Cu-substituted Pd(1 1 1) surfaces as well as the PdM/γ-Al2O3(1 1 0) (M = Au, Ag, Cu) surfaces has been investigated using spin-polarized density functional theory calculations. It is found that M-substituted Pd(1 1 1) surfaces show as good Hg adsorption capacity as the perfect Pd(1 1 1) at low Hg coverage, while the Hg adsorption capacity is only slightly weakened at high Hg coverage. On the basis of stepwise adsorption energies analysis, it is concluded that M-substituted Pd(1 1 1) surfaces can contribute to the binding of Hg atom on the surfaces at high Hg coverage. The electronic properties of the second metal atoms are the main factor contributes to the Hg adsorption capacity. Gas phase Pd2 shows better Hg adsorption capacity than Pd2/γ-Al2O3, while PdM/γ-Al2O3 can adsorb Hg more efficiently than bare PdM clusters. It suggests that the γ-Al2O3 support can enhance the activity of PdM for Hg adsorption and reduces the activity of Pd2. It is also found that Pd is the main active composition responsible for the interaction of mercury with the surface for PdM/γ-Al2O3 sorbent. Taking Hg adsorption capacity and economic costs into account, Cu addition is a comparatively good candidate for Hg capture.

  16. Band-Structure Effects in the High-Field Magnetization of Pd and Dilute Pd-Rh and Pd-Ag Alloys

    DEFF Research Database (Denmark)

    Andersen, O. Krogh

    1970-01-01

    be derived solely from the band density of states N(E). The previously reported Pd band-structure calculations, which were in excellent agreement with the de Haas-van Alphen data, have been extended to yield DeltaB(sigma) for Pd and, using the rigid band model, also for dilute Pd[Single Bond]Rh and Pd......From Stoner theory we show that the magnetic field-vs-spin magnetization has the form B(sigma)=sigma/chi(0)+DeltaB(sigma). The low-field susceptibility chi(0) is exchange-enhanced but, if the effective exchange potential does not depend on magnetization, the deviation from linearity DeltaB may......; moreover, the experimental data have previously been analyzed according to a power series expansion of sigma(B) that neither separates the effect of band structure from that of exchange enhancement nor applies when van Hove singularities are important. Our formulation suggests a way of analyzing...

  17. Sonochemical synthesis of a PdAg/C electrocatalyst for oxygen reduction reaction; Sintesis sonoquimica de un electrocatalizador de PdAg/C para la reaccion de reduccion de oxigeno

    Energy Technology Data Exchange (ETDEWEB)

    Godinez-Garcia, A.; Perez-Robles, J.F. [Centro de Investigacion y de Estudios Avanzados del IPN. Santiago de Queretaro, Queretaro (Mexico)]. E-mail: jperez@qro.cinvestav.mx; Solorza-Feria, O. [CINVESTAV-IPN, Mexico, D.F. (Mexico)

    2009-09-15

    The synthesis and characterization of nanocatalysts for fuel cells has been a primary line of research for the purpose of obtaining less expensive electrocatalysts with better activity. A large variety of methods exist to synthesize useful nanoparticles as electrocatalysts. Each method generates particles with a different surface morphology and, therefore, the catalytic activity usually varies depending on which is used in the synthesis. In this work, PdAg/C electrocatalysts are synthesized with high-intensity ultrasonic irradiation and compared to those obtained using a conventional method such as reduction by NaBH{sub 4}. The study of this technique is of interest because it produces highly dispersed carbon-supported nanoparticles with very clean surfaces. Each electrocatalyst was evaluated for its oxygen reduction reaction (ORR) in acid medium with cyclic voltamperometry (CV) and rotating disc electrode (RDE). The electrocatalyst was characterized with x-ray diffraction and transmission electron microscopy (TEM). The physical characterization reveals that the electrocatalyst is composed of nanometric bimetallic aggregates. An important characteristic of the PdAg/C alloy obtained using ultrasound is better activity than that obtained by reduction with NaBH{sub 4}. [Spanish] La sintesis y caracterizacion de nanocatalizadores para celdas de combustible ha sido una de las principales lineas de investigacion, con el objetivo de obtener electrocatalizadores mas baratos y con una mejor actividad. Existen una gran variedad de metodos para sintetizar nanoparticulas utiles como electrocatalizadores, cada metodo genera particulas con una morfologia superficial diferente por lo que la actividad catalitica suele variar dependiendo de cual se utilice en la sintesis. En este trabajo se sintetizan electrocatalizadores de PdAg/C con irradiacion ultrasonica de alta intensidad y se comparan con las obtenidas con un metodo convencional como es la reduccion por NaBH{sub 4}. Esta

  18. The secondary electron yield of TiZr and TiZrV non evaporable getter thin film coatings

    CERN Document Server

    Scheuerlein, C; Hilleret, Noël; Taborelli, M

    2001-01-01

    The secondary electron yield (SEY) of two different non evaporable getter (NEG) samples has been measured 'as received' and after thermal treatment. The investigated NEGs are TiZr and TiZrV thin film coatings of 1 mm thickness, which are sputter deposited onto copper substrates. The maximum SEY dmax of the air exposed TiZr and TiZrV coating decreases from above 2.0 to below 1.1 during a 2 hour heat treatment at 250 °C and 200 °C, respectively. Saturating an activated TiZrV surface under vacuum with the gases typically present in ultra high vacuum systems increases dmax by about 0.1. Changes in elemental surface composition during the applied heat treatments were monitored by Auger electron spectroscopy (AES). After activation carbon, oxygen and chlorine were detected on the NEG surfaces. The potential of AES for detecting the surface modifications which cause the reduction of SE emission during the applied heat treatments is critically discussed.

  19. The adhesion performance of epoxy coating on AA6063 treated in Ti/Zr/V based solution

    Science.gov (United States)

    Zhu, Wen; Li, Wenfang; Mu, Songlin; Yang, Yunyu; Zuo, Xi

    2016-10-01

    An environment-friendly titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating was prepared on aluminum alloy 6063 (AA6063). The epoxy powder coatings were applied on the AA6063 samples with/without Ti/Zr/V conversion coatings via electrostatic spraying. The morphology and composition of the conversion coating were studied by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The surface free energy components of AA6063 samples were measured by a static contact angle measuring device with Owens method. The adhesion properties of the epoxy coating on AA6063 treated with different conversion times were evaluated using a pull-off tester. The Ti/Zr/V conversion coating was mainly composed of metal oxide (TiO2, ZrO2, V2O5, Al2O3, etc.), metal fluoride (ZrF4, AlF3, etc.) and metal organic complex. The formation time of this conversion coating was reduced to 50 s. After such surface treatment, the samples' surface roughness was increased and the contact angle with water was decreased. Both the surface free energy and the work of adhesion were increased. The adhesion strength between the epoxy coating and AA6063 was enhanced significantly.

  20. Investigation of nanostructured Pd-Ag/n-ZnO thin film based Schottky junction for methane sensing

    Science.gov (United States)

    Roy, S.; Das, S.; Sarkar, C. K.

    2016-07-01

    Undoped nanocrystalline n-type ZnO thin film was deposited by chemical deposition technique on a thermally oxidized p-Si (~5 Ω cm resistivity and orientation) substrate. Formation of stable zinc oxide thin film was confirmed by two-dimensional X-Ray Diffraction (XRD) and EDX analysis. The average crystallite size of the ZnO sample was evaluated as ~50 nm. The surface was characterized by Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM) that confirm the formation of nanocrystalline (grain size ~50 nm) ZnO thin film with surface roughness of ~100 nm. Good conversion of precursor into ZnO thin film in the chemical deposition method was evident by Fourier Transform Infrared Spectroscopy (FTIR). A small peak at 479 cm-1was observed in the FTIR spectrum confirming the formation of quartzite structure of the ZnO. The band gap (~3.44 eV) of the material was calculated from the optical absorption spectroscopy. To prepare Pd-Ag/n-ZnO Schottky junction, Pd-Ag contacts were taken by electron beam evaporation method. I-V characteristics of the junction were studied at different temperatures in inert and reducing ambient (N2 and N2 + CH4) with turn on voltage of around 0.2 V. The parameters like ideality factor ( η), saturation current ( I 0), series resistance ( Rs), and barrier height ( Φ BO) of the junction were calculated in the temperature range 50-200 °C in N2 as well as in 1 % CH4 + N2 ambient. It was observed that the ideality factor decreases in the temperature range 50-200 °C ( η = 12.34 at 50 °C and η = 1.52 at 200 °C) in N2 ambient and η = 1.18 in N2 +CH4 ambient at 200 °C. Schottky Barrier Height ( Φ BO) of the Pd-Ag/n-ZnO junction was found to increase with temperature. A close observation of Pd-Ag/n-ZnO junction in the presence of methane was performed to appreciate its application as methane sensor. The sensing mechanism was illustrated by a simplified energy band diagram.

  1. Strain gradient related uphill hydrogen diffusion phenomena in Pd[sub 77]Ag[sub 23]H[sub n

    Energy Technology Data Exchange (ETDEWEB)

    Tong, X.Q. (School of Chemistry, Queen' s Univ., Belfast, Northern Ireland (United Kingdom)); Bucur, R.V. (Chemistry Inst., Univ. of Uppsala (Sweden)); Kandasamy, K. (School of Chemistry, Queen' s Univ., Belfast, Northern Ireland (United Kingdom)); Lewis, F.A. (School of Chemistry, Queen' s Univ., Belfast, Northern Ireland (United Kingdom))

    1993-01-01

    In recent studies of hydrogen diffusion in the Pd[sub 77]Ag[sub 23]H[sub n] system by absorption techniques, uphill type non-Fickian effects have been associated with lattice strain gradients produced either by external mechanical forces or by the permeating interstitials themselves. Converse downhill effects with reversed direction of permeation recorded in analogous desorption measurements for a range of initial membrane hydrogen contents provide self consistent allied support for interpretations in terms of a Gorsky effect operation which is additional to the usual Fickian one. (orig.)

  2. Relationship between element-selective electronic states and hydrogen absorption properties of Pd-M (M =Ru ,Rh,Ag, and Au) alloys

    Science.gov (United States)

    Fujii, Kanako; Ishimatsu, Naoki; Maruyama, Hiroshi; Shishidou, Tatsuya; Hayakawa, Shinjiro; Kawamura, Naomi

    2017-01-01

    To understand how the constituent atoms participate in the hydrogenation of Pd-based alloys at ˜0.1 MPa of hydrogen pressure (PH2),we investigated the electronic states in Pd-M (M =Ru,Rh,Ag, and Au) alloys and their hydrides element-selectively by using x-ray absorption spectroscopy at the L2 ,3 edges. Spectral changes near the absorption edge demonstrate that both Pd and M atoms form bonds with H atoms in the Pd-M (M =Ru and Rh) alloys even at PH 2˜0.1 MPa. This is a striking result because high pressures of more than 1 GPa are required for the hydrogenation of Rh and Ru pure metals. In contrast, only Pd atoms bond with H atoms and the M -H bond is absent in the case of Pd-M (M =Ag and Au) alloys. Therefore, the hydrogen-induced changes in the electronic states differ between M s with fully occupied d shells and M s with partially occupied d shells. This study reveals that the thermodynamic hydrogenation properties of Pd-M alloys can be determined by a combination of the formation of the M -H bond and lattice expansion or compression by alloying Pd metal with M .

  3. Clinical Acceptability of the Internal Gap of CAD/CAM PD-AG Crowns Using Intraoral Digital Impressions.

    Science.gov (United States)

    Kim, Tae-Gyung; Kim, Sungtae; Choi, Hyunmin; Lee, Jae-Hoon; Kim, Jae-Hong; Moon, Hong-Seok

    2016-01-01

    The purpose of this study was to compare the internal gap between CAD/CAM palladium-silver crowns and cast gold crowns generated from intraoral digital versus conventional impressions and to determine the clinical acceptability. Nickel-chrome master dies were made from the prepared resin tooth with the conventional impression method (n = 40). For ICC (Intraoral, CAD/CAM) group, 10 intraoral digital impressions were made, and 10 CAD/CAM crowns of a PD-AG (palladium-silver) machinable alloy were generated. For IC (Intraoral, Cast) group, 10 gold crowns were cast from ten intraoral digital impressions. For CCC (Conventional, CAD/CAM) group, 10 CAD/CAM PD-AG crowns were made using the conventional impression method. For CC (Conventional, Cast) group, 10 gold crowns were fabricated from 10 conventional impressions. One hundred magnifications of the internal gaps of each crown were measured at 50 points with an optical microscope and these values were statistically analyzed using a two-way analysis of variance (α = 0.05). The internal gap of the intraoral digital impression group was significantly larger than in the conventional impression group (P CAD/CAM group and the cast group (P > 0.05). Within the limitations of this in vitro study, crowns from intraoral digital impressions showed larger internal gap values than crowns from conventional impressions.

  4. Clinical Acceptability of the Internal Gap of CAD/CAM PD-AG Crowns Using Intraoral Digital Impressions

    Directory of Open Access Journals (Sweden)

    Tae-Gyung Kim

    2016-01-01

    Full Text Available The purpose of this study was to compare the internal gap between CAD/CAM palladium-silver crowns and cast gold crowns generated from intraoral digital versus conventional impressions and to determine the clinical acceptability. Nickel-chrome master dies were made from the prepared resin tooth with the conventional impression method (n=40. For ICC (Intraoral, CAD/CAM group, 10 intraoral digital impressions were made, and 10 CAD/CAM crowns of a PD-AG (palladium-silver machinable alloy were generated. For IC (Intraoral, Cast group, 10 gold crowns were cast from ten intraoral digital impressions. For CCC (Conventional, CAD/CAM group, 10 CAD/CAM PD-AG crowns were made using the conventional impression method. For CC (Conventional, Cast group, 10 gold crowns were fabricated from 10 conventional impressions. One hundred magnifications of the internal gaps of each crown were measured at 50 points with an optical microscope and these values were statistically analyzed using a two-way analysis of variance (α=0.05. The internal gap of the intraoral digital impression group was significantly larger than in the conventional impression group (P0.05. Within the limitations of this in vitro study, crowns from intraoral digital impressions showed larger internal gap values than crowns from conventional impressions.

  5. Room temperature hydrogen generation from hydrolysis of ammonia-borane over an efficient NiAgPd/C catalyst

    KAUST Repository

    Hu, Lei

    2014-12-01

    NiAgPd nanoparticles are successfully synthesized by in-situ reduction of Ni, Ag and Pd salts on the surface of carbon. Their catalytic activity was examined in ammonia borane (NH3BH3) hydrolysis to generate hydrogen gas. This nanomaterial exhibits a higher catalytic activity than those of monometallic and bimetallic counterparts and a stoichiometric amount of hydrogen was produced at a high generation rate. Hydrogen production rates were investigated in different concentrations of NH3BH3 solutions, including in the borates saturated solution, showing little influence of the concentrations on the reaction rates. The hydrogen production rate can reach 3.6-3.8 mol H2 molcat -1 min-1 at room temperature (21 °C). The activation energy and TOF value are 38.36 kJ/mol and 93.8 mol H2 molcat -1 min-1, respectively, comparable to those of Pt based catalysts. This nanomaterial catalyst also exhibits excellent chemical stability, and no significant morphology change was observed from TEM after the reaction. Using this catalyst for continuously hydrogen generation, the hydrogen production rate can be kept after generating 6.2 L hydrogen with over 10,000 turnovers and a TOF value of 90.3 mol H2 molcat -1 min-1.

  6. Effects of Drawing and Annealing on Properties of Ag-4Pd Alloy Bonding Wire%冷变形和热处理对Ag-4Pd键合合金线性能影响

    Institute of Scientific and Technical Information of China (English)

    曹军; 范俊玲; 高文斌

    2016-01-01

    通过对Ag-4Pd键合合金线冷加工和热处理过程中的微观组织与性能进行研究,分析了冷变形加工率和热处理温度对Ag-4Pd键合合金线力学性能、组织结构和熔断电流的影响。研究结果表明:Ag-4Pd键合合金线随冷加工率增长,强度增加,伸长率降低,滑移和孪生变形为主要形变类型;随着热处理温度的增加,f0.050 mm Ag-4Pd键合合金线拉断力下降,伸长率增加,525℃热处理时,Ag-4Pd键合合金线具有优秀的力学性能;进一步增加热处理温度,Ag-4Pd键合合金线出现孪晶组织,且孪生形核及亚晶吞并长大形核为主要形核方式;热处理过程中施加在线材上的拉紧力过大,导致Ag-4Pd键合合金线表面呈凹凸不平的微小竹节状;经试验数据拟合,Ag-4Pd 键合合金线电阻值随热处理温度升高而降低,其熔断电流与熔断时间之间存在指数函数关系,Ag-4Pd键合合金线熔断电流与弧长之间存多项式函数关系。%The micro-structure and properties of Ag-4Pd alloy bonding wire after drawing and heat treatment are investigated, and effects of drawing rate and heat treatment temperature on mechanical properties, structure and fusing current of Ag-4Pd alloy bonding are are analyzed. The results show that the strength of Ag-4Pd alloy bonding wire will increase, and the elongation will decrease when drawing rate increased, the main deformation type are flip and twin. Forf 0.050 mmAg-Pd alloy bonding wire, the broken load decreases and elongation increases when heat treatment temperature increases, the mechanical properties are excellent after heat treatment at 525℃. When increase heat treatment temperature more, the twin crystal is found in Ag-4Pd alloy bonding wire, and twin nucleation and subgrain grows are the main nucleation. The micro bamboo defects on surface are found after heat treatment with excessive tensile load. The electrical resistance of Ag-4Pd

  7. Distribution of Precious Metals (Ag, Au, Pd, Pt, and Rh) Between Copper Matte and Iron Silicate Slag

    Science.gov (United States)

    Avarmaa, Katri; Johto, Hannu; Taskinen, Pekka

    2016-02-01

    The distributions of precious metals (Ag, Au, Pd, Pt, and Rh) between copper matte and silica-saturated iron silicate slag were determined at 1523 K to 1623 K (1250 °C to 1350 °C), in controlled CO-CO2-SO2-Ar gas mixtures. The experiments were done in silica crucibles and a fixed partial pressure of sulfur dioxide for matte grades of 55, 65, and 75 wt pct Cu. High-temperature equilibration/quenching/electron probe X-ray microanalysis technique was used to obtain compositions of the equilibrated matte and slag. The technique was applied for the first time to the distributions of precious metals in simulated flash smelting conditions. The resolution of electron probe microanalysis became critical as the detection limits were insufficient to measure reliably the precious metals concentrations (except silver) in the slag. The distribution coefficient of silver, L m/s[Ag] = [wt pctAg in matte]/(wt pctAg in slag), was found to be between 200 and 300, which agrees well with the latest studies in the literature. For other precious metals, the minimum values of distribution coefficients were determined according to the detection limits in the slag. The values obtained were for gold and platinum >250, for palladium >1000, and for rhodium >900. The distribution coefficients of palladium, although locating above distribution coefficient of the detection limit, formed a clear dependency with a good repeatability as a function of the matte grade. It increased along with matte grade and was approximately 1000 at 50 pct Cu and 2000 to 3000 at 70 pct Cu. The precious metals replace metal in the matte structure and they are present as sulfides in the copper matte.

  8. Effect of SO2 on the performance of Ag-Pd/Al2O3 for the selective catalytic reduction of NOx with C2H5OH

    Institute of Scientific and Technical Information of China (English)

    XIE Shu-xia; YU Yun-bo; WANG Jin; HE Hong

    2006-01-01

    The influence of SO2 on the performance of Ag-Pd/Al2O3 for the selective catalytic reduction (SCR) of NOx with C2H5OH was investigated experimentally. The activity test results suggest that Ag-Pd/Al2O3 shows a small activity loss in the presence of SO2 when using C2H5OH as a reductant. In situ DRIFTS spectra show that the activity loss originates from the formation of surface sulphate species on the Ag-Pd/Al2O3. The surface sulphate species formation inhibits the formation of nitrate, whereas hardly changes the partial oxidation of C2H5OH. Compared with the NOx reduction by C3H6, an obvious suppression of the surface sulphate species formation was observed by DRIFTS experiment when using C2H5OH as a reductant. This phenomenon reveals the better catalytic performance and strong SO2 tolerance of Ag-Pd/Al2O3-C2H5OH system.

  9. 自研牙科低金含量银钯合金与2种商品钯银合金的显微硬度比较%Comparison of micro-hardness between experimental low-gold Ag-Pd alloy and 2 commercial Pd-Ag alloys

    Institute of Scientific and Technical Information of China (English)

    田保; 潘小波

    2011-01-01

    Objective To compare micro-hardness of experimental low-gold Ag-Pd alloy and 2 commercial Pd-Ag alloy.Methods Prepare 10mm × 10mm × lmm casting from alloys. Specimens from 2 commercial Pd-Ag alloys were treated according to instructions, and the specimens from experimental low-gold Ag-Pd alloy were solution treated and iso-thermal treated at 459℃ followed by quenching. After grinding and polishing, test micro-Vickes' s hardness of all specimens. Results After solution treated, the micro-Vicker' s hardness of experimental low-gold Ag-Pd alloy was 42% and 39% of the commercial Pd-Ag alloys, respectively. After iso-thermal treated at 459℃ followed by quenching, the hardness reached 95% and 89% of the commercial Pd-Ag alloys, respectively. Conclusion After iso-thermal treatd, the hardness of experimental low-gold Ag-Pd alloy reached 95%and 89% of the commercial Pd-Ag alloys, respectively, and satisfied the standard of ADA for Ⅳ gold alloy.%目的 比较自研牙科低金含量银钯合金与2种商品牙科合金的显微硬度.方法 分别将3种合金材料铸造为10mm×10mm×1mm的试样.2种商品合金材料按照说明书进行热处理,自研合金材料先进行固溶处理,之后在459℃等温热处理10min后淬火冷却.金相抛光后试样进行显微维氏硬度测量.结果 与2种商品合金相比,自研牙科低金含量银钯合金固溶处理后合金的硬度分别是其显微硬度的42%、39%,热处理后合金的硬度是其显微硬度的95%,89%.结论 自研牙科低金含量银钯合金经过适当的热处理,最高硬度分别达到2种商品合金显微硬度的95%,89%,满足ADA IV类金合金的硬度标准.

  10. Formation of L1{sub 0}-type ordered {beta} Prime phase in as-solutionized dental Ag-Pd-Au-Cu alloys and hardening behavior

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yonghwan [Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6 Aoba, Aramaki Aza, Aoba-ku, Sendai 980-8579 (Japan); Niinomi, Mitsuo, E-mail: niinomi@imr.tohoku.ac.jp [Department of Biomaterials Science, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Hieda, Junko; Nakai, Masaaki [Department of Biomaterials Science, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Fukui, Hisao [Department of Dental Materials Science, School of Dentistry, Aichi-Gakuin University, Nagoya 464-0045 (Japan)

    2012-04-01

    The relationship between the microstrucutural changes of L1{sub 0}-type ordered {beta} Prime phase and hardening behavior in as-solutionized dental Ag-Pd-Au-Cu alloys was investigated by changing the cooling rate and the solution treatment temperature. Additionally, the formation process of the {beta} Prime phase in as-solutionized Ag-Pd-Au-Cu alloy was attempted to clarify. The microstructural changes were observed by X-ray diffraction (XRD) method and transmission electron microscopy (TEM). The hardness was evaluated using a Vickers microhardness tester. The {beta} Prime phase is precipitated regardless of the cooling rate, after solution treatment at 1123 K. TEM dark field images show that the size of the {beta} Prime phase decreases and the number of {beta} Prime phase increases with an increase in the cooling rate. The Vickers hardness value increases with an increase in cooling rate. TEM dark field images show that the microstructure of {beta} Prime phase is similar when the solution treatment temperature increases from 1123 K to 1173 K. However, the Vickers hardness increases with an increase of solution treatment temperature. It is of great significance to reveal that the {beta} Prime phase precipitated in as-solutionized Ag-Pd-Au-Cu alloy is formed during cooling after high-temperature solution treatment and that the growth of the {beta} Prime phase is diffusion controlled. - Highlights: Black-Right-Pointing-Pointer The microstructure of {beta} Prime phase of Ag-Pd-Au-Cu alloy is changed by cooling rates. Black-Right-Pointing-Pointer The {beta} Prime phase is formed during the cooling process. Black-Right-Pointing-Pointer Growth of the {beta} Prime phase is dominated by diffusion. Black-Right-Pointing-Pointer Hardness of Ag-Pd-Au-Cu alloy increases remarkably with precipitation of the {beta} Prime phase.

  11. Environmentally benign synthesis of amides and ureas via catalytic dehydrogenation coupling of volatile alcohols and amines in a Pd-Ag membrane reactor

    KAUST Repository

    Chen, Tao

    2016-05-31

    In this study, we report the direct synthesis of amides and ureas via the catalytic dehydrogenation of volatile alcohols and amines using the Milstein catalyst in a Pd-Ag/ceramic membrane reactor. A series of amides and ureas, which could not be synthesized in an open system by catalytic dehydrogenation coupling, were obtained in moderate to high yields via catalytic dehydrogenation of volatile alcohols and amines. This process could be monitored by the hydrogen produced. Compared to the traditional method of condensation, this catalytic system avoids the stoichiometric pre-activation or in situ activation of reagents, and is a much cleaner process with high atom economy. This methodology, only possible by employing the Pd-Ag/ceramic membrane reactor, not only provides a new environmentally benign synthetic approach of amides and ureas, but is also a potential method for hydrogen storage.

  12. Copper-based alloys, crystallographic and crystallochemical parameters of alloys in binary systems Cu-Me (Me=Co, Rh, Ir, Cu, Ag, Au, Ni, Pd, Pt)

    Energy Technology Data Exchange (ETDEWEB)

    Porobova, Svetlana, E-mail: porobova.sveta@yandex.ru; Loskutov, Oleg, E-mail: lom58@mail.ru [Tomsk State University of Architecture and Building, Russia, Tomsk, 2 Solyanaya sq, Tomsk, 634003 (Russian Federation); Markova, Tat’jana, E-mail: patriot-rf@mail.ru [Siberian State Industrial University. 42 Kirov St., Novokuznetsk, 654007 (Russian Federation); Klopotov, Vladimir, E-mail: vdklopotov@mail.ru [Research Tomsk Polytechnic University, 30 Lenin Ave., Tomsk, 634050 (Russian Federation); Klopotov, Anatoliy, E-mail: klopotovaa@tsuab.ru [Tomsk State University of Architecture and Building, Russia, Tomsk, 2 Solyanaya sq, Tomsk, 634003 (Russian Federation); National Research Tomsk State University, 36, Lenin Ave., Tomsk, 634050 (Russian Federation); Vlasov, Viktor, E-mail: vik@tsuab.ru [Tomsk State University of Architecture and Building, Russia, Tomsk, 2 Solyanaya sq, Tomsk, 634003 (Russian Federation); Research Tomsk Polytechnic University, 30 Lenin Ave., Tomsk, 634050 (Russian Federation)

    2016-01-15

    The article presents the results of the analysis of phase equilibrium of ordered phases in binary systems based on copper Cu- Me (where Me - Co, Rh, Ir, Ag, Au, Ni, Pd, Pt) to find correlations of crystallochemical and crystallographic factors. It is established that the packing index in disordered solid solutions in binary systems based on copper is close to the value of 0.74 against the background of an insignificant deviation of atomic volumes from the Zen’s law.

  13. Reducing the Ideal Shear Strengths of ZrB2 by High Efficient Alloying Elements (Ag, Au, Pd and Pt)

    Science.gov (United States)

    Dai, Fu-Zhi; Zhou, Yanchun

    2017-02-01

    Activating the plasticity of ZrB2 is a promising approach to improve its key properties for applications in hypersonic vehicles, including high temperature strength and thermal shock resistance. The present work demonstrates that ideal shear strength of ZrB2, which is a good indicator of the critical stress for dislocation nucleation, can be significantly reduced by dissolving of appropriate alloying elements. Analyzing on the bonding nature of ZrB2 reveals that choosing alloying elements with low energy valence electrons will prevent electron transferring from alloying element to the electron deficient B-B π orbits, which will reduce the local stability of the region surrounding the alloying element. Under the criterion, elements with d electrons tending to be full-filled (Ag, Au, Pd and Pt, the full-filled state is associated with low energy level) are selected as promising candidates with their prominent efficiency in reducing ideal shear strengths verified by first-principles calculations. The results provide useful guidelines for further designs of ZrB2 based materials, especially for improving their mechanical properties.

  14. Reducing the Ideal Shear Strengths of ZrB2 by High Efficient Alloying Elements (Ag, Au, Pd and Pt).

    Science.gov (United States)

    Dai, Fu-Zhi; Zhou, Yanchun

    2017-02-24

    Activating the plasticity of ZrB2 is a promising approach to improve its key properties for applications in hypersonic vehicles, including high temperature strength and thermal shock resistance. The present work demonstrates that ideal shear strength of ZrB2, which is a good indicator of the critical stress for dislocation nucleation, can be significantly reduced by dissolving of appropriate alloying elements. Analyzing on the bonding nature of ZrB2 reveals that choosing alloying elements with low energy valence electrons will prevent electron transferring from alloying element to the electron deficient B-B π orbits, which will reduce the local stability of the region surrounding the alloying element. Under the criterion, elements with d electrons tending to be full-filled (Ag, Au, Pd and Pt, the full-filled state is associated with low energy level) are selected as promising candidates with their prominent efficiency in reducing ideal shear strengths verified by first-principles calculations. The results provide useful guidelines for further designs of ZrB2 based materials, especially for improving their mechanical properties.

  15. Quantitative description of short-range order and its influence on the electronic structure in Ag-Pd alloys

    Science.gov (United States)

    Hoffmann, M.; Marmodoro, A.; Ernst, A.; Hergert, W.; Dahl, J.; Lång, J.; Laukkanen, P.; Punkkinen, M. P. J.; Kokko, K.

    2016-08-01

    We investigate the effect of short-range order (SRO) on the electronic structure in alloys from the theoretical point of view using density of states (DOS) data. In particular, the interaction between the atoms at different lattice sites is affected by chemical disorder, which in turn is reflected in the fine structure of the DOS and, hence, in the outcome of spectroscopic measurements. We aim at quantifying the degree of potential SRO with a proper parameter. The theoretical modeling is done with the Korringa-Kohn-Rostoker Green’s function method. Therein, the extended multi-sublattice non-local coherent potential approximation is used to include SRO. As a model system, we use the binary solid solution Ag c Pd1-c at three representative concentrations c  =  0.25, 0.5 and 0.75. The degree of SRO is varied from local ordering to local segregation through an intermediate completely uncorrelated state. We observe some pronounced features, which change over the whole energy range of the valence bands as a function of SRO in the alloy. These spectral variations should be traceable in modern photoemission experiments.

  16. Modeling and simulation of ammonia removal from purge gases of ammonia plants using a catalytic Pd-Ag membrane reactor.

    Science.gov (United States)

    Rahimpour, M R; Asgari, A

    2008-05-01

    In this work, the removal of ammonia from synthesis purge gas of an ammonia plant has been investigated. Since the ammonia decomposition is thermodynamically limited, a membrane reactor is used for complete decomposition. A double pipe catalytic membrane reactor is used to remove ammonia from purge gas. The purge gas is flowing in the reaction side and is converted to hydrogen and nitrogen over nickel-alumina catalyst. The hydrogen is transferred through the Pd-Ag membrane of tube side to the shell side. A mathematical model including conservation of mass in the tube and shell side of reactor is proposed. The proposed model was solved numerically and the effects of different parameters on the rector performance were investigated. The effects of pressure, temperature, flow rate (sweep ratio), membrane thickness and reactor diameter have been investigated in the present study. Increasing ammonia conversion was observed by raising the temperature, sweep ratio and reducing membrane thickness. When the pressure increases, the decomposition is gone toward completion but, at low pressure the ammonia conversion in the outset of reactor is higher than other pressures, but complete destruction of the ammonia cannot be achieved. The proposed model can be used for design of an industrial catalytic membrane reactor for removal of ammonia from ammonia plant and reducing NO(x) emissions.

  17. Montmorillonite-supported Pd0, Fe0, Cu0 and Ag0 nanoparticles: Properties and affinity towards CO2

    Science.gov (United States)

    Bouazizi, Nabil; Barrimo, Diana; Nousir, Saadia; Ben Slama, Romdhane; Roy, René; Azzouz, Abdelkrim

    2017-04-01

    This study reports the carbon dioxide (CO2) adsorption on montmorillonite (NaMt) incorporating Cu0, Fe0, Pd0 and Ag0 as metallic nanoparticles (MNPs). The changes in structural, textural, morphological and adsorption properties of the resulting materials (NaMt-MNPs) were investigated. Electron microscopy and X-ray diffraction showed that dispersion of fine MNPs occurs mainly within the interlayer space of NaMt, producing a slight structure expansion. This was accompanied by a visible enhancement of the affinity towards CO2, as supported by thermal programmed desorption measurements. NaMt-MNPs displayed high CO2 retention capacity (CRC) of ca. 657 μmol/g for NaMt-Cu as compared to NaMt. This was explained in terms of increased number of available adsorption sites due to enlarged interlayer spaces caused by MNP insertion. The differences in CO2 adsorption capacities clearly demonstrate the key role of MNPs in improving the surface properties and adsorption capacity. The results reported herein open new prospects for clay supported metal nanoparticles as efficient adsorbents for CO2.

  18. Solubility and diffusivity of hydrogen in palladium and Pd sub 77 Ag sub 23 containing lattice defects

    Energy Technology Data Exchange (ETDEWEB)

    Bucur, R.V.; Ersson, N.O. (Inst. of Chemistry, Univ. of Uppsala (Sweden)); Tong, X.Q. (Dept. of Chemistry, Queen' s Univ., Belfast (United Kingdom) Dept. of Materials Science and Engineering, Tsinghua Univ., Beijing (China))

    1991-08-30

    The energy of interstitial sites in a palladium alloy depends considerably on the nature and concentration of the alloying substituent. However, the microstructure of the sample (e.g. grain boundaries, dislocations) may also contribute to a certain extent to these alterations. In some cases it is expected that the effect of these defects may be opposite to that of the substituent, while in other cases both contributions have similar directional influences. In either circumstance the strength of the interaction of hydrogen atoms with the interstitial sites will be affected. The aim of this paper is to investigate the contribution of defects to the solubility and diffusivity of hydrogen in Pd{sub 77}Ag{sub 23} alloy. The measurements have been carried out on samples with and without defects, in the Sieverts domain (293-335 K) using a computer-assisted electrochemical method. The results are discussed in terms of Oriani's two-state model and compared with similar data obtained with palladium samples. (orig.).

  19. Inhibiting the growth of Cu3Sn and Kirkendall voids in the Cu/Sn-Ag-Cu system by minor Pd alloying

    Science.gov (United States)

    Ho, Cheng En; Kuo, Tsai Tung; Wang, Chun Chien; Wu, Wei Hsiang

    2012-10-01

    In this study, the metallurgical reaction between Cu substrates (electrolytic type) and a Sn3Ag0.5Cu-xPd alloy at 180°C was examined using a scanning electron microscope (SEM), electron probe microanalyzer (EPMA), focused ion beam (FIB) microscope, and transmission electron microscope (TEM). The results showed that the growth of Cu3Sn in the Cu/Sn-Ag-Cu solder joints was substantially suppressed by doping with a minor quantity of Pd (0.1-0.7 wt. %) in the solder alloy. The sluggish growth of Cu3Sn reduced the formation of Kirkendall voids at the Cu/Cu3Sn interface and significantly improved the mechanical reliability of the joint interface. It was argued that a minor addition of Pd into the solder stabilized the Cu6Sn5 phase and enlarged the interdiffusion coefficient of Cu6Sn5 but diminished that of the neighboring phase (Cu3Sn), thereby decreasing the Kirkendall effect in the Cu/Sn-Ag-Cu reactive system.

  20. A simple approach to uniform PdAg alloy membranes: Comparative study of conventional and silver concentration-controlled co-plating

    KAUST Repository

    Zeng, Gaofeng

    2014-03-01

    An Ag-controlled co-plating method was developed for the preparation of palladium/silver alloy membranes on porous tubular alumina supports. By controlling the feed rate of Ag to the Pd bath, the concentration of the silver in the plating bath was restricted during the course of plating. As a result, preferential deposition of silver at the beginning was suppressed and uniform dispersion of silver inside the membrane with silver composition in the desired range was achieved. Ultrathin (∼2.5 μm) PdAg alloy membranes with uniform silver composition of ∼25% were successfully obtained. The membrane showed a hydrogen permeance of 0.88 mol m-2 s-1 and pure-gas H2/N2 selectivity of 2140 at 823 K with ΔP = 100 kPa. Only one hydride phase existed in the studied temperature range from 373 to 823 K with ΔPH=100kPa. Direct comparisons with the conventional simply-mixed co-plating method showed that membranes made by the novel Ag-controlled co-plating method had much more uniform silver distribution, smoother surface, denser membrane structure, higher utilization rate of metal sources, and shorter alloying time. © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  1. Influence of the elemental composition and crystal structure on the vacuum properties of Ti-Zr-V non-evaporable getter films

    CERN Document Server

    Prodromides, A E; Chiggiato, P; Mongelluzzo, A; Ruzinov, V; Scheuerlein, C; Taborelli, M; Lévy, F

    2001-01-01

    Non-evaporable thin film getters based on the elements of the 4th and 5th columns of the periodic table have been deposited by sputtering. Among the about 20 alloys studied to date, the lowest activation temperature (about 180 °C for a 24-hour heating) has been found for the Ti-Zr-V system in a well-defined composition range. The characterization of the activation behavior of such Ti-Zr-V films is presented. The evolution of the surface chemical composition during activation is monitored by Auger Electron Spectroscopy (AES) and the functional properties are evaluated by pumping speed measurements. The pumping speed characteristics are quite similar to those already measured for commercially available NEG materials, except for the much lower saturation coverage for CO. This inconvenience, which is due to the smooth surface structure of these films, can be counteracted by increasing the roughness of the substrate.

  2. Validation of an air-liquid interface toxicological set-up using Cu, Pd, and Ag well-characterized nanostructured aggregates and spheres

    Science.gov (United States)

    Svensson, C. R.; Ameer, S. S.; Ludvigsson, L.; Ali, N.; Alhamdow, A.; Messing, M. E.; Pagels, J.; Gudmundsson, A.; Bohgard, M.; Sanfins, E.; Kåredal, M.; Broberg, K.; Rissler, J.

    2016-04-01

    Systems for studying the toxicity of metal aggregates on the airways are normally not suited for evaluating the effects of individual particle characteristics. This study validates a set-up for toxicological studies of metal aggregates using an air-liquid interface approach. The set-up used a spark discharge generator capable of generating aerosol metal aggregate particles and sintered near spheres. The set-up also contained an exposure chamber, The Nano Aerosol Chamber for In Vitro Toxicity (NACIVT). The system facilitates online characterization capabilities of mass mobility, mass concentration, and number size distribution to determine the exposure. By dilution, the desired exposure level was controlled. Primary and cancerous airway cells were exposed to copper (Cu), palladium (Pd), and silver (Ag) aggregates, 50-150 nm in median diameter. The aggregates were composed of primary particles Viability was measured by WST-1 assay, cytokines (Il-6, Il-8, TNF-a, MCP) by Luminex technology. Statistically significant effects and dose response on cytokine expression were observed for SAEC cells after exposure to Cu, Pd, or Ag particles. Also, a positive dose response was observed for SAEC viability after Cu exposure. For A549 cells, statistically significant effects on viability were observed after exposure to Cu and Pd particles. The set-up produced a stable flow of aerosol particles with an exposure and dose expressed in terms of number, mass, and surface area. Exposure-related effects on the airway cellular models could be asserted.

  3. Magnetic behaviour of Ce(Pd{sub 1-x}M{sub x}) compounds (M=Rh, Ni and Ag) within the LDA approximation

    Energy Technology Data Exchange (ETDEWEB)

    Vildosola, V.L.; Llois, A.M. E-mail: llois@cnea.gov.ar; Weissmann, M.; Sereni, J.G

    2001-10-01

    Ce intermetallic compounds have been intensively studied in the last few decades due to the large variety of behaviours they exhibit. In particular, two ways of demagnetizing Ce have been experimentally tried within the ferromagnetic systems Ce(Pd{sub 1-x}M{sub x}), namely through electronic concentration variations (M=Rh) and volume reductions (M=Ni). On the other hand, when Pd is substituted by Ag, a transformation from a ferromagnetic to an antiferromagnetic ground state has been observed. In this work, we analyse the evolution of the magnetism of Ce in the above-mentioned family of compounds by calculating the spin contribution to magnetism that results from spin polarised LDA calculations.

  4. Hydrogen production using Ag-Pd/TiO2 bimetallic catalysts: is there a combined effect of surface plasmon resonance with the Schottky mechanism on the photo-catalytic activity?(Conference Presentation)

    Science.gov (United States)

    Nadeem, Muhammad Amtiaz; Idriss, Hicham; Al-Oufi, Maher; Ahmed, Khaja Wahab; Anjum, Dalaver H.

    2016-10-01

    A series of Ag-Pd/TiO2 catalysts have been prepared, characterized and tested for H2 production activities from water in the presence of organic sacrificial agents. The synergistic effect of metallic properties (plasmonic and Schottky mechanisms) was investigated. XPS results indicated that silver is present in the form of its oxides (Ag2O and AgO) at 0.2-0.4 wt. % loading while palladium is present as PdO and Pd metal at similar loading. However, metallic character for silver particles increases while that of palladium metal particles decreases with increasing their % in the investigated range (0-1 wt. %). HRTEM results coupled with EDX analyses indicated the presence of two types of Ag containing particles (large ones with about 4-6 nm and smaller ones with ca. 1nm in size). Palladium was only found forming Ag-Pd alloy/composite with a wide size distribution range between 10-60 nm. Both particles are composed of silver and palladium, however. Optimal photocatalytic H2 production rates were obtained for catalysts with a palladium to silver ratios between 4 and 1.5 in the case of bimetallic catalysts. In addition, H2 production rates showed linear dependency on plasmonic response of Ag. The study demonstrates that increased H2 production rates can be achieved from an understanding of plasmonic and Schottky properties of metals loaded on top of the semiconductor.

  5. Development of casting investment preventing blackening of noble metal alloys part 1. Application of developed investment for Ag-Pd-Cu-Au alloy.

    Science.gov (United States)

    Kakuta, Kiyoshi; Nakai, Akira; Goto, Shin-ichi; Wakamatsu, Yasushi; Yara, Atushi; Miyagawa, Yukio; Ogura, Hideo

    2003-03-01

    The objective of this study is to develop a casting investment that prevents the blackening of the cast surface of noble metal alloys. The experimental investments were prepared using a gypsum-bonded investment in which the metallic powders such as boron (B), silicon (Si), aluminum (Al) and titanium (Ti) were added as oxidizing agents. An Ag-Pd-Cu-Au alloy was cast into the mold made of the prepared investment. The effect of the addition of each metal powder was evaluated from the color difference between the as-cast surface and the polished surface of the cast specimen. The color of the as-cast surface approached that of the polished surface with increasing B and Al content. A lower mean value in the color difference was obtained at 0.25-1.00 mass% B content. B and Al are useful as an additive in a gypsum-bonded investment to prevent the blackening of an Ag-Pd-Cu-Au alloy. The effects of Si and Ti powder addition could not be found.

  6. Room temperature biogenic synthesis of multiple nanoparticles (Ag, Pd, Fe, Rh, Ni, Ru, Pt, Co, and Li) by Pseudomonas aeruginosa SM1

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Sarvesh Kumar; Constanti, Magda, E-mail: magdalena.constanti@urv.cat [Universitat Rovira i Virgili, Departament d' Enginyeria Quimica (Spain)

    2012-03-15

    Room temperature biosynthesis of Ag, Pd, Fe, Rh, Ni, Ru, Pt, Co, and Li nanoparticles was achieved using Pseudomonas aeruginosa SM1 without the addition of growth media, electron donors, stabilizing agents, preparation of cell/cell-free extract or temperature, and pH adjustments. The resulting nanoparticles were characterized by Transmission electron microscopy and X-ray diffraction. It was observed that P. aeruginosa SM1 is capable of producing both intracellular (Co and Li) and extracellular (Ag, Pd, Fe, Rh, Ni, Ru, and Pt) nanoparticles in both crystalline and amorphous state. The FT-IR spectra clearly showed the presence of primary and secondary amines which may be responsible for the reduction and subsequent stabilization of the resulting extracellular nanoparticles which were obtained as a one-step process. This suggests toward an unknown 'selection mechanism' that reduces certain metal ions and allows others to enter the cell membrane. Finally, in this first of its kind study, single strain of bacteria was used to produce several different mono-metallic nanoparticles.

  7. Self-consistent linear-muffin-tin-orbitals coherent-potential technique for bulk and surface calculations: Cu-Ni, Ag-Pd, and Au-Pt random alloys

    DEFF Research Database (Denmark)

    Abrikosov, I. A.; Skriver, Hans Lomholt

    1993-01-01

    energies and work functions for three fcc-based alloys (Cu-Ni, Ag-Pd, and Au-Pt) over the complete concentration range. The calculated mixing enthalpies for the Ag-Pd and Au-Pt systems agrees with experimental values, and the calculated concentration dependence of the lattice parameters agrees...... with experiment for all three systems. We find that the calculated surface energies and work functions in the unsegregated case exhibit a small positive deviation from a linear concentration dependence. Finally, we performed a segregation analysis based on the calculated surface energies by means of a simple...

  8. Competition between ferromagnetism and frustrated antiferromagnetism in quasi 2D Ce2.15(Pd1-x Ag x )1.95In0.9 alloys

    Science.gov (United States)

    Sereni, J. G.; Giovannini, M.; Gómez Berisso, M.; Gastaldo, F.

    2016-11-01

    Low temperature thermal and magnetic measurements performed on ferro-magneticl (FM) alloys of composition Ce2.15(Pd1-x Ag x )1.95In0.9 are presented. Pd substitution by Ag depresses {{T}\\text{C}}(x) from 4.1 K down to 1.1 K for x  =  0.5, which is related to the increase of band electrons, with a critical concentration extrapolated to {{x}\\text{cr}}≈ 0.6 . The {{T}\\text{C}}(x) decrease is accompanied by a weakening of the magnetization of the FM phase. At high temperature (T  >  30 K) the inverse magnetic susceptibility reveals the presence of robust magnetic moments (2.56≥slant ~{μ\\text{eff}}≥slant 2.4 {μ\\text{B}} ), whereas the low value of the Curie-Weiss temperature {θP}≈ -10 K excludes any relevant effect from Kondo screening. The specific heat jump at {{T}\\text{C}}(x) decreases accordingly, while an anomaly emerges at a fixed temperature {{T}\\ast}≈ 1 K. This unexpected anomaly does not show any associated sign of magnetism checked by AC-susceptibility measurements. Since the total magnetic entropy (evaluated around T={{T}\\text{C}}(x=0) ) practically does not change with Ag concentration, the transference of degrees of freedom from the FM component to the non-magnetic T * anomaly is deduced. The origin of this anomaly is attributed to an arising magnetic frustration of the ground state and the consequent entropy bottleneck produced by the divergent increasing of density of excitations at low temperature.

  9. The crystal structures of jaguéite, Cusub>2sub>Pd>3sub>Se>4sub>, and chrisstanleyite, Agsub>2sub>Pd>3sub>Se>4sub>

    DEFF Research Database (Denmark)

    Topa, Dan; Makovicky, Emil; Balic Zunic, Tonci

    2006-01-01

    -radiation. There are two unique Pd sites, one Cu (or Ag) and two Se sites in the unit cell. Atom Pd1 forms isolated square arrangements PdSe4, whereas the adjacent arrangements involving Pd2 are paired via a common edge. The (Cu,Ag) coordination tetrahedra form (100) layers which, together with the Pd2-Cu(Ag)-Pd1-Cu...

  10. Ag/TiO2,Pd/TiO2和TiO2对庚烷的光催化氧化活性%Photocatalytic Activity of Ag/TiO2, Pd/TiO2 and TiO2 for the Photocatalytic Oxidation of Gaseous Heptane

    Institute of Scientific and Technical Information of China (English)

    刘洋; 尚静

    2005-01-01

    用光沉积法制备Ag/TiO2和Pd/TiO2催化剂样品,然后用表面光电压谱(SPS)和紫外可见吸收光谱(UV-Vis)对样品进行表征.以气态庚烷为反应体系,来比较上述两种催化剂的光催化活性.与纯TiO2比较,Ag和Pd的存在提高了TiO2的光催化活性;其原因可解释为金属Ag或Pd捕获电子,从而提高了电子-空穴对的分离效率;结果还表明与Pd/TiO2催化剂相比,Ag/TiO2表现出较高的光催化活性,这主要是Ag比Pd具有较强的捕获电子的能力.

  11. 阻断PD-1/PD-L1信号通路对负载HBsAg的树突细胞抗HBV免疫功能的影响%Effect of programmed death-1/progranuned death ligand-1 interaction on immune response of HBsAg-pulsed denddtic cells to hepatitis B virus

    Institute of Scientific and Technical Information of China (English)

    郭忠胜; 潘修成; 陈明; 杨帆; 李丽; 张言超; 李秀华

    2010-01-01

    目的 探讨阻断PD-1/PD-L1信号通路后,负载HBsAg的树突细胞(dendritic cells,DC)诱导HBV转基因小鼠免疫应答的作用特点.方法 体外诱导扩增BALB/c小鼠骨髓来源的DC,尾静脉免疫HBV转基因小鼠(其中在DC免疫前1 d腹腔注射PD-L1抗体,共3次).实验分5组进行:DC/HBsAg+PD-L1抗体组、DC/HBsAg组、Dc组、mlgG组和磷酸盐缓冲液(PBS)组,分别以流式细胞术、乳酸脱氢酶(LDH)释放法、酶联免疫吸附试验(ELISA)和荧光定量聚合酶链反应(PCR)等检测HBV转基因小鼠脾脏淋巴细胞增殖及细胞内干扰素γ(IFNγ)、特异性细胞毒性T淋巴细胞(CTL)活性及血清HBsAg、HBV DNA和丙氨酸转氨酶(ALT)水平.采用SPSS 13.0统计软件进行分析,组间比较采用ANOVA方差分析和q检验.结果免疫后第3天和第6天,DC/HBsAg+PD-L1抗体组与其他各组比较在诱导CD_3~+CD_8~+T淋巴细胞增殖及IFNγ分泌方面差异有统计学意义(细胞增殖:F值分别为25.22和39.01,P值均<0.01;IFNγ分泌:F值分别为32.35和36.98,P值均<0.01);而DC/HBsAg组与Dc组淋巴细胞增殖能力比较仅在第3天有统计学意义(t=6.79,P=0.012).特异性CTL的活性在DC/HBsAg+PD-L1抗体组明显升高.各组血清HBsAg在第6天差异有统计学意义(F=6.12,P<0.05).DC/HBsAg+PD-L1抗体组血清ALT水平与DC/HBsAg组比较在第3天无差异,与其他各组比较在第3和第6天差异有统计学意义(F值分别为19.22和14.30,P值均<0.05).各组对HBV DNA的清除能力没有差别,但DC/HBsAg+PD-L1抗体组有1只小鼠病毒载量下降1个数量级.结论封闭PD-1/PD-L1信号通路能通过提高特异性CD_3~+CD_8~+T淋巴细胞增殖及其分泌IFNγ能力,进而促进负载HBsAg的DC诱导转基因小鼠抗HBV免疫能力.%Objective To investigate the effect of programmed death(PD)-1/PD-L1 interaction on immunc response of HBsAg-pulsed dendritic cells(DCs)vaccine.Methods DCs were genermed from bone marrow cells from BALB/c mice and pulsed with HBsAg

  12. Adsorption properties of Ag(I), Au(III), Pd(II) and Pt(IV) ions on commercial 717 anion-exchange resin

    Institute of Scientific and Technical Information of China (English)

    LIU Peng; LIU Guang-feng; CHEN Da-lin; CHENG Shao-yi; TANG Ning

    2009-01-01

    The adsorption properties of the four precious metal ions (Ag(Ⅰ),Au(Ⅲ),Pd(Ⅱ) and Pt(Ⅳ)) on the commercial Cl--form 717 strongly basic anion-exchange resin were studied in detail.The effects of the contact time,solution acidity,and concentrations of Cl~- and Pb~(2+) ions on the adsorption properties were studied by the batch method.Then,the column method was conducted under the optimized adsorption conditions (pH=3.0).The effects of the sample loading flow rate and the length-to-diameter ratios of the columns were investigated.The precious metal ions adsorbed could not be eluted completely after the saturated adsorption because the precious metal ions were found to be reduced to their metallic states during the adsorption process.So,it is recommended that the commercial Cl~--form 717 strongly basic anion-exchange resin should be decomposed directly to recovery the precious metals after the saturated adsorption.

  13. Pd-Ag Membrane Coupled to a Two-Zone Fluidized Bed Reactor (TZFBR for Propane Dehydrogenation on a Pt-Sn/MgAl2O4 Catalyst

    Directory of Open Access Journals (Sweden)

    Miguel Menéndez

    2013-05-01

    Full Text Available Several reactor configurations have been tested for catalytic propane dehydrogenation employing Pt-Sn/MgAl2O4 as a catalyst. Pd-Ag alloy membranes coupled to the multifunctional Two-Zone Fluidized Bed Reactor (TZFBR provide an improvement in propane conversion by hydrogen removal from the reaction bed through the inorganic membrane in addition to in situ catalyst regeneration. Twofold process intensification is thereby achieved when compared to the use of traditional fluidized bed reactors (FBR, where coke formation and thermodynamic equilibrium represent important process limitations. Experiments were carried out at 500–575 °C and with catalyst mass to molar flow of fed propane ratios between 15.1 and 35.2 g min mmol−1, employing three different reactor configurations: FBR, TZFBR and TZFBR + Membrane (TZFBR + MB. The results in the FBR showed catalyst deactivation, which was faster at high temperatures. In contrast, by employing the TZFBR with the optimum regenerative agent flow (diluted oxygen, the process activity was sustained throughout the time on stream. The TZFBR + MB showed promising results in catalytic propane dehydrogenation, displacing the reaction towards higher propylene production and giving the best results among the different reactor configurations studied. Furthermore, the results obtained in this study were better than those reported on conventional reactors.

  14. Ag和Pd及其离子对TiO2光催化分解CH3CHO的影响%The effects of Ag, Pd and Ag+, Pd2+ on photodegradation of CH3CHO catalyzed by TiO2

    Institute of Scientific and Technical Information of China (English)

    姚晓斌; 马颖; 姚建年

    1999-01-01

    @@ 当用能量大于其禁带宽度的光照射通有氧气的TiO2悬浮液时,在TiO2微粒表面会产生反应活性很高的空穴和O2-、H2O2等多种活性氧.在上一篇文章中[1]我们已报道了在通氧气和紫外光照的条件下,向TiO2悬浮液中加入少量Ag+或Pd2+,将会大幅度提高体系中H2O2的生成量.

  15. Liquid-Phase Ethanol Oxidation and Gas-Phase CO Oxidation Reactions over M Doped (M = Ag, Au, Pd, and Ni and MM′ Codoped CeO2 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Yohan Park

    2016-01-01

    Full Text Available Transition metal doped metal oxides have been studied extensively for potential applications to environments and chemical industry. Herein, M doped (M = Ag, Au, Pd, and Ni and MM′ codoped CeO2 nanoparticles (NPs were prepared by a hydrothermal method and their liquid-phase ethanol and gas-phase CO oxidation performances were examined by UV-visible absorption spectroscopy and temperature programmed mass spectrometry, respectively. The ethanol and CO oxidation performances were enhanced greatly by metal-doping and were dependent on the relative concentration of codoped metals. For ethanol oxidation, the concentration of acetaldehyde became saturated at low levels, while that of ethyl acetate continuously increased to become a final major product. For M doped CeO2 NPs, the ethanol oxidation performance showed an order of Ni < Ag < Pd ≪ Au. For MM′ codoped CeO2 NPs, the activity of Au doped CeO2 deteriorated drastically upon adding other metals (Ag, Ni, and Pd as a cocatalyst.

  16. Production of ultrapure hydrogen in a Pd-Ag membrane reactor using Ru/La{sub 2}O{sub 3} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Faroldi, B.; Carrara, C.; Lombardo, E.A.; Cornaglia, L.M. [Instituto de Investigaciones en Catalisis y Petroquimica (FIQ, UNL-CONICET), Santiago del Estero, 2829-3000 Santa Fe (Argentina)

    2007-03-01

    Ru catalysts supported on lanthanum oxide with different loadings were prepared by wet impregnation. These solids were characterized by laser Raman spectroscopy (LSR), XPS, XRD and TPR. The catalytic activity toward hydrogen production through the dry reforming of methane was determined in a fixed-bed reactor and a membrane reactor. The reaction rate expressed per gram of Ru decreased when the metal loading increased. In the Pd-Ag membrane reactor, when the sweep gas flow rate (SG) increased, the conversions overcame the equilibrium values and the difference between CH{sub 4} and CO{sub 2} conversions decreased. Both Ru(0.6) and Ru(1.2) catalysts were able to restore the equilibrium for the dry reforming reaction up to values of SG = 30 ml min{sup -1}; Ru(0.6) was the most effective catalyst. By employing a CO{sub 2}/CH{sub 4} 1 and a SG of 0.05 mmol s{sup -1}, both a high H{sub 2} permeation flux of 5.68 x 10{sup -7} mol s{sup -1} m{sup -2} and a hydrogen recovery of 80% were obtained. Both the TPR and the Raman spectroscopy data indicated the presence of Ru(III) strongly interacting with La. Significantly, this observation was further confirmed by the appearance of Ru(III) on the surface. When the Ru content increased, the higher Ru 3d binding energy component was proposed as arising from Ru(IV). Concerning the Ru(1.2) solid, the presence of Ru(IV) was detected by means of TPR experiments, in agreement with the high proportion of Ru(IV) on the surface. Therefore, a fraction of Ru loading was present in this solid as species with weaker metal-support interaction leading to the slight deactivation of this catalyst in the membrane reactor. (author)

  17. Superior effect of Ni-substitution on the hydrogenation kinetics of Mg{sub 6}Pd{sub 1−x}TM{sub x} (TM = Ag, Cu, Ni) pseudo-binary compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ponthieu, M. [MIRE-Group, Laboratorio de Física de Materiales de Interés Energético, Dpto Física de Materiales, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid (Spain); ICMPE/CNRS-UPEC, UMR 7182, 2-8 rue Henri Dunant, 94320 Thiais (France); Fernández, J.F., E-mail: josefrancisco.fernandez@uam.es [MIRE-Group, Laboratorio de Física de Materiales de Interés Energético, Dpto Física de Materiales, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Cuevas, F. [ICMPE/CNRS-UPEC, UMR 7182, 2-8 rue Henri Dunant, 94320 Thiais (France); Laversenne, L. [Institut Néel, CNRS, Grenoble (France); Bodega, J.; Ares, J.R.; Sánchez, C. [MIRE-Group, Laboratorio de Física de Materiales de Interés Energético, Dpto Física de Materiales, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid (Spain)

    2015-10-05

    Highlights: • Kinetics of (de)hydrogenation of Mg{sub 6}(Pd,TM) TM = Ag, Cu and Ni compared. • Faster hydrogenation kinetics for the Ni compound. • Faster H-desorption for the Ni compound due to MgH{sub 2}/Mg{sub 2}NiH{sub 4} synergy. - Abstract: In this investigation, the H-sorption kinetics of Mg{sub 6}Pd and Mg{sub 6}Pd{sub 1−x}TM{sub x} (TM = Ag, Cu, Ni) pseudo-binary compounds at the TM solubility limit have been studied by isothermal hydrogen absorption, thermal desorption spectroscopy and in situ neutron diffraction. Among all studied compounds, the fastest absorption kinetics takes place for the Ni-substituted one. The fit of the absorption curves to established model equations for solid–gas reaction shows that hydrogenation is controlled by diffusion. As for desorption, the peak temperature for the Ni-substituted compound is 90 K below that of MgH{sub 2}/Mg system and is characterised by a low activation energy of 68 kJ/molH{sub 2}. To better understand these results, neutron diffraction experiments during in situ thermal desorption of deuterated Mg{sub 6}Pd and Mg{sub 6}Pd{sub 0.25}Ni{sub 0.75} compounds were carried out. These experiments demonstrate a synergetic effect between MgH{sub 2} and Mg{sub 2}NiH{sub 4} hydrides as responsible for the remarkable kinetics of the Ni-containing compound.

  18. Research on Pd film deposition rate calculation and simulation based on TiZrV/Pd film coating experiment

    CERN Document Server

    Wang, Jie; Xu, Yanhui; Wang, Yong

    2015-01-01

    The vacuum chamber of accelerator storage ring need clean ultra-high vacuum environment. TiZrV getter film which was deposited on interior wall of vacuum chamber, can realize distributed pumping, effectively improve the vacuum degree and reduce the longitudinal gradient. But accumulation of pollutants such as N2, O2, will decrease the adsorption ability of non-evaporable getter (NEG), which leads to the reduction of NEG lifetime. Therefore, NEG thin film coated with a layer of Pd which has high diffusion rate and absorption ability for H2, can extend the service life of NEG, and improve the pumping rate of H2 at the same time. With argon as discharge gas, magnetron sputtering method was adopted to prepare TiZrV-Pd film in long straight pipe. According to the experimental results of the scanning electron microscope (SEM), deposition rates of TiZrV-Pd films were analyzed under different deposition parameters, the magnetic field strength, the gas flow rate, discharge current, discharge voltage and working pressu...

  19. Reversed-Phase Liquid Chromatographic Separation and Determination of Ni(II, Cu(II, Pd(II, and Ag(I Using 2-Pyrrolecarboxaldehyde-4-phenylsemicarbazone as a Complexing Reagent

    Directory of Open Access Journals (Sweden)

    Arfana Mallah

    2013-01-01

    Full Text Available This paper reports the utilization of 2-pyrrolecarboxaldehyde-4-phenylsemicarbazone (PPS as a complexing reagent for the simultaneous determination and separation of Ni(II, Cu(II, Pd(II, and Ag(I by reversed-phase high-performance liquid chromatography with UV detector. A good separation was achieved using Microsorb C18 column (150 × 4.6 mm i.d. with a mobile phase consisted of methanol : acetonitrile : water : sodium acetate (1 mM (68 : 6.5 : 25 : 0.5 v/v/v/v at a flow rate of 1 mL/min. The detection was performed at 280 nm. The linear calibration range was 2–10 μg/mL for all metal ions. The detection limits (S/N = 3 were 80 pg/mL for Ni(II, 0.8 ng/mL for Cu(II, 0.16 ng/mL for Pd(II, and 0.8 ng/mL for Ag(I. The applicability and the accuracy of the developed method were estimated by the analysis of Ni(II in hydrogenated oil (ghee samples and Pd(II in palladium charcoal.

  20. Ag对Pd/CeO2-ZrO2-La2O3-Al2O3催化氧化甲醇性能的影响%Effects of Ag on Performance of Methanol Oxidation over Pd/CeO2-ZrO2-La2O3-Al2O3

    Institute of Scientific and Technical Information of China (English)

    张雪乔; 王世丹; 信欣; 刘盛余; 陈耀强; 赵明

    2012-01-01

    采用等体积共浸渍法制备了一系列Pd-Ag/CeO2-ZrO2-La2O3-Al2O3催化剂.运用N2吸附-脱附,X射线衍射(XRD),H2程序升温还原(H2-TPR),紫外-可见漫反射光谱(UV-Vis DRS),X射线光电子能谱(XPS)对催化剂进行表征,并考察其对甲醇的催化氧化性能.活性测试结果表明,Ag的添加可显著改善Pd催化剂对甲醇的催化氧化活性,T50、T90以及△T分别为125℃,150℃和25℃,具有较好的应用前景.H2-TPR表明,引入Ag可明显改善催化剂的还原性能,使表面易还原氧物种量增多,还原速率加快;UV-Vis DRS及XPS表明,Pd、Ag金属之间以及金属与载体之间存在电子效应,这种效应促使金属与载体界面产生大量具有活性的氧物种,不仅提高了催化剂的低温活性,还提高了催化剂的氧化速率.%Pd-Ag/CeO2-ZrO2-La2O3-Al2O3 catalysts were prepared by the co-impregnation method. Low temperature nitrogen adsorption-desorption, X-ray diffraction (XRD), H2-temperature-programmed reduction (H2-TPR), Ultra violet-visble difuse reflectance spectroscopy (UV-Vis DRS) and X-ray photoelectron spectroscopy (XPS) were carried out. The catalytic activities of these catalysts for the oxidation of methanol were investigated. The results of catalytic activity indicate that the presence of Ag significantly improves catalytic performance for methanol oxidation. The T50, T90 and △T are 125℃, 150 ℃ and 25℃, respectively. H2-TPR results suggest that the addition of Ag increases the amount of active oxygen and promotes the reductive ability. The UV-Vis DRS and XPS results indicate that electron effects between Pd and Ag, Pd-Ag and support are favorable for producing larger activated oxygen via easy migration on the Pd-Ag/CeO2 interface, thus promoting both the catalytic activity at low temperature and the speed of catalytic oxidation.

  1. Casting of MOD inlay using rings with holes on both sides: 12∼18 wt%Au-20∼26Pd-14.48∼26.48Cu-40Ag-1.5Zn-0.02Ir alloys.

    Science.gov (United States)

    Ohkuma, Kazuo; Kazama, Miku; Ogura, Hideo

    2012-01-01

    Using a casting ring with openings on both sides and a water-absorbent polymer, heterogeneity is maintained in a single casting and a precise MOD inlay can be produced. We produced 9 different kinds of gold-silver-palladium (Au-Ag-Pd) alloys by changing the ratio of palladium, gold, and copper and investing them, and changing parameters such as the angulation of the casting ring openings and the water:powder ratios to produce MOD inlay castings. We measured the expansion and shrinkage percentage of the castings in both the buccolingual and mesiodistal directions. From this experiment, we learned that precise MOD inlay castings can be produced using rings with 240° openings when invested in a thick mix having a standard water:powder ratio or using rings with 200° openings when invested in a thick mix having a water:powder ratio for a 12 wt%Au-20∼26Pd-20.48∼26.48Cu-40Ag-1.5Zn-0.02Ir alloyes.

  2. Influence of the noble metals (Pd, Au, Ag) in the thermoluminescent signal induced by radiation in the ZrO{sub 2}; Influencia de los metales nobles (Pd, Au, Ag) en la senal termoluminiscente inducida por la radiacion en la ZrO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Villa S, G

    2006-07-01

    When increasing the use of the ionizing and non ionizing radiations (for example, gamma and ultraviolet radiation) in different areas of the science and technology, there is necessary to apply more accurate safety measures and to avoid over-exposures that could put in risk the life of workers that manipulate radiation sources, patient that are exposed to this under some medical treatment, as well as materials that undergo intentionally to radiation. Also, the UV radiation that arrives to the earth can cause some damages, to the one to weaken the protector layer of ozone the UV radiation increases that arrives to the earth surface being able to affect the alive beings and the materials. By this so much the development of new materials able to take a census of in a more accurate way, fields of gamma and UV radiation is becoming necessary. In this sense, this work presents the obtained results when quantifying radiation fields, through the analysis in the thermoluminescent behavior (TL) induced by the gamma and UV radiation in the zirconium dioxide synthesized by the sol gel method and doped with nanoparticles of Pd, Au and Ag. It is necessary to mention that in reported works in this respect its mention that the zircon has good thermoluminescent sensitivity induced by these radiation types, however it has shown high thermoluminescent instability that is translated in an important lost of the information after the irradiation. For that through the incorporation of the metallic nanoparticles it was intended to stabilize the TL behavior of zircon. The results showed that the doped zircon has a high sensitivity to the gamma and UV radiation. These also show that the ionizing and non ionizing radiation induce a thermoluminescent curve consisting of two TL peaks with maxima located around 65 C and 145 C and that the intensity is increased with the dose, following a lineal behavior in certain interval of dose exposure that is influenced by the presence of the nanoparticles

  3. Ag对Pd/CeO2催化剂上氧迁移的促进作用%Enhanced Migration of Oxygen on Ag-Modified Pd/CeO2 Catalyst

    Institute of Scientific and Technical Information of China (English)

    曲振平; 程谟杰; 石川; 黄伟新; 包信和

    2001-01-01

    @@Active migration and spillover of surface species on catalyst surface can be cri tical effects in catalytic processes. As a typical instance, the storage and rel ease of oxygen in the Pt-modified CeO2 catalysts were proposed to play a very important role in catalytic elimination of noxious pollutants[1]. It ha s been demonstrated that the active oxygen species transfer between Pt and CeO 2 under different conditions[2,3]. Numerous investigations on the proper ty of Pd in the catalysts have been carried out recently[4]. Compared wi th Pt, Pd has a strong interaction with CeO2 support. Silver is a unique eleme nt whose oxide can decompose thermally

  4. Recubrimientos de Pd (Ag)-ZrO2 obtenidos por CVD para electrodos utilizados en la purificación electroquímica de aguas de desecho

    OpenAIRE

    Ferrétiz Anguiano, Jorge Luis

    2013-01-01

    In this research Pd – ZrO2 composite thin films were synthetized by Metalorganic Chemical Vapor Deposition (MOCVD) in order to obtain anticorrosive coatings for electrodes used in the technique of water treatment called Electrodyalisis. Coatings were deposited on AISI 304L stainless steel substrates in ratios of 10 – 90, 20 – 80 and 30 – 70 wt % Pd and Zr precursors (acetylacetonates) respectively, and temperatures of 450, 500 and 550 °C. Gas flows were adjusted at 130 cm3min-1 at ratio of 20...

  5. Preparation Methods and Properties of PdCu Alloy Membrane for Hydrogen Transition

    Institute of Scientific and Technical Information of China (English)

    SUN Xiaoliang; MA Guang; LI Jin; ZHANG Ke

    2012-01-01

    Pd and Pd alloy membranes are of increasing interest for hydrogen separation and purification due to their good thermal stability,high permeability and perfect selectivity.PdCu alloy (60wt% Pd) membranes have similar hydrogen permeability compared with PdAg alloy; meanwhile,it is cheaper than PdAg alloy.Furthermore,it has been reported that PdCu membrane has better resistance to poisoning and deactivation by H2S impurity.This paper reviews the properties and manufacturing methods of PdCu alloy membrane,finally,introduced some achievement made by us on PdCu alloy membrane.

  6. Elastic properties of antiperovskite-type Ni-rich nitrides MNNi 3 (M=Zn, Cd, Mg, Al, Ga, In, Sn, Sb, Pd, Cu, Ag and Pt) as predicted from first-principles calculations

    Science.gov (United States)

    Bannikov, V. V.; Shein, I. R.; Ivanovskii, A. L.

    2010-11-01

    We have performed accurate ab initio total energy calculations using the full-potential linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA) for the exchange-correlation potential to systematically investigate elastic properties of 12 synthesized and hypothetical cubic antiperovskite-type Ni-rich nitrides MNNi 3, where M are Zn, Cd, Mg, Al, Ga, In, Sn, Sb, Pd, Cu, Ag and Pt. As a result, the optimized lattice parameters, independent elastic constants ( Cij), bulk-, shear- and tetragonal shear moduli, Cauchy’s pressure and some indexes of elastic anisotropy, as well as the numerical estimations of Young’s modulus, Poisson’s ratio and Pugh's indicator of brittle/ductile behavior for the corresponding polycrystalline MNNi 3 (in the Voigt-Reuss-Hill approximation) were obtained and analyzed in comparison with the available theoretical and experimental data.

  7. Elastic properties of antiperovskite-type Ni-rich nitrides MNNi{sub 3} (M=Zn, Cd, Mg, Al, Ga, In, Sn, Sb, Pd, Cu, Ag and Pt) as predicted from first-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Bannikov, V.V.; Shein, I.R. [Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Sciences, 620990 Ekaterinburg (Russian Federation); Ivanovskii, A.L., E-mail: ivanovskii@ihim.uran.r [Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Sciences, 620990 Ekaterinburg (Russian Federation)

    2010-11-15

    We have performed accurate ab initio total energy calculations using the full-potential linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA) for the exchange-correlation potential to systematically investigate elastic properties of 12 synthesized and hypothetical cubic antiperovskite-type Ni-rich nitrides MNNi{sub 3}, where M are Zn, Cd, Mg, Al, Ga, In, Sn, Sb, Pd, Cu, Ag and Pt. As a result, the optimized lattice parameters, independent elastic constants (C{sub ij}), bulk-, shear- and tetragonal shear moduli, Cauchy's pressure and some indexes of elastic anisotropy, as well as the numerical estimations of Young's modulus, Poisson's ratio and Pugh's indicator of brittle/ductile behavior for the corresponding polycrystalline MNNi{sub 3} (in the Voigt-Reuss-Hill approximation) were obtained and analyzed in comparison with the available theoretical and experimental data.

  8. The role of charge transfer in the oxidation state change of Ce atoms in the TM13-CeO2(111) systems (TM = Pd, Ag, Pt, Au): a DFT + U investigation.

    Science.gov (United States)

    Tereshchuk, Polina; Freire, Rafael L H; Ungureanu, Crina G; Seminovski, Yohanna; Kiejna, Adam; Da Silva, Juarez L F

    2015-05-28

    Despite extensive studies of transition metal (TM) clusters supported on ceria (CeO2), fundamental issues such as the role of the TM atoms in the change in the oxidation state of Ce atoms are still not well understood. In this work, we report a theoretical investigation based on static and ab initio molecular dynamics density functional theory calculations of the interaction of 13-atom TM clusters (TM = Pd, Ag, Pt, Au) with the unreduced CeO2(111) surface represented by a large surface unit cell and employing Hubbard corrections for the strong on-site Coulomb correlation in the Ce f-electrons. We found that the TM13 clusters form pyramidal-like structures on CeO2(111) in the lowest energy configurations with the following stacking sequence, TM/TM4/TM8/CeO2(111), while TM13 adopts two-dimensional structures at high energy structures. TM13 induces a change in the oxidation state of few Ce atoms (3 of 16) located in the topmost Ce layer from Ce(IV) (itinerant Ce f-states) to Ce(III) (localized Ce f-states). There is a charge flow from the TM atoms to the CeO2(111) surface, which can be explained by the electronegativity difference between the TM (Pd, Ag, Pt, Au) and O atoms, however, the charge is not uniformly distributed on the topmost O layer due to the pressure induced by the TM13 clusters on the underlying O ions, which yields a decrease in the ionic charge of the O ions located below the cluster and an increase in the remaining O ions. Due to the charge flow mainly from the TM8-layer to the topmost O-layer, the charge cannot flow from the Ce(IV) atoms to the O atoms with the same magnitude as in the clean CeO2(111) surface. Consequently, the effective cationic charge decreases mainly for the Ce atoms that have a bond with the O atoms not located below the cluster, and hence, those Ce atoms change their oxidation state from IV to III. This increases the size of the Ce(III) compared with the Ce(IV) cations, which builds-in a strain within the topmost Ce layer, and

  9. Intermetallic compounds of the heaviest elements and their homologs: The electronic structure and bonding of MM', where M =Ge, Sn, Pb, and element 114, and M'=Ni, Pd, Pt, Cu, Ag, Au, Sn, Pb, and element 114

    Science.gov (United States)

    Pershina, V.; Anton, J.; Fricke, B.

    2007-10-01

    Fully relativistic (four-component) density-functional theory calculations were performed for intermetallic dimers MM', where M =Ge, Sn, Pb, and element 114, and M'=group 10 elements (Ni, Pd, and Pt) and group 11 elements (Cu, Ag, and Au). PbM and 114M, where M are group 14 elements, were also considered. The results have shown that trends in spectroscopic properties—atomization energies De, vibrational frequencies ωe, and bond lengths Re, as a function of M', are similar for compounds of Ge, Sn, Pb, and element 114, except for De of PbNi and 114Ni. They were shown to be determined by trends in the energies and space distribution of the valence ns(M ') atomic orbitals (AOs). According to the results, element 114 should form the weakest bonding with Ni and Ag, while the strongest with Pt due to the largest involvement of the 5d(Pt) AOs. In turn, trends in the spectroscopic properties of MM' as a function of M were shown to be determined by the behavior of the np1/2(M ) AOs. Overall, De of the element 114 dimers are about 1eV smaller and Re are about 0.2a.u. larger than those of the corresponding Pb compounds. Such a decrease in bonding of the element 114 dimers is caused by the large SO splitting of the 7p orbitals and a decreasing contribution of the relativistically stabilized 7p1/2(114) AO. On the basis of the calculated De for the dimers, adsorption enthalpies of element 114 on the corresponding metal surfaces were estimated: They were shown to be about 100-150kJ/mol smaller than those of Pb.

  10. PD Lab

    OpenAIRE

    Bilow, Marcel; Entrop, Bram; Lichtenberg, Jos; Stoutjesdijk, Pieter

    2015-01-01

    PD Lab explores the applications of building sector related product development. PD lab investigates and tests digital production technologies like CNC milled wood connections. It will also act as a platform in its wider meaning to investigate the effects and influences of file to factory production, to explore the potential in the field of sustainability, material use, logistics and the interaction of stakeholders within the chain of the building process.

  11. Depletion and phase transformation of a submicron Ni(P) film in the early stage of soldering reaction between Sn-Ag-Cu and Au/Pd(P)/Ni(P)/Cu

    Science.gov (United States)

    Ho, Cheng-En; Hsieh, Wan-Zhen; Yang, Tsung-Hsun

    2015-01-01

    The early stage of soldering reaction between Sn-3Ag-0.5Cu solder and ultrathin-Ni(P)-type Au/Pd(P)/Ni(P)/Cu pad was investigated by field-emission scanning electron microscopy (FE-SEM) in conjunction with field-emission electron probe microanalysis (FEEPMA) and high-resolution transmission electron microscopy (HRTEM). FE-SEM, FE-EPMA, and HRTEM investigations showed that Ni2SnP and Ni3P were the predominant P-containing intermetallic compounds (IMCs) in the soldering reaction and that their growth behaviors strongly depended on the depletion of Ni(P). The growth of Ni3P dominated over that of Ni2SnP in the early stage of soldering, whereas the Ni3P gradually transformed into Ni2SnP after Ni(P) depletion. This Ni(P)-depletion-induced Ni2SnP growth behavior is different from the reaction mechanisms reported in the literature. Detailed analyses of the microstructural evolution of the IMC during Ni(P) depletion were conducted, and a two-stage reaction mechanism was proposed to rationalize the unique IMC growth behavior.

  12. Layer-by-Layer Self-Assembled Metal-Ion- (Ag-, Co-, Ni-, and Pd- Doped TiO2 Nanoparticles: Synthesis, Characterisation, and Visible Light Degradation of Rhodamine B

    Directory of Open Access Journals (Sweden)

    Mphilisi M. Mahlambi

    2012-01-01

    Full Text Available Metal-ion- (Ag, Co, Ni and Pd doped titania nanocatalysts were successfully deposited on glass slides by layer-by-layer (LbL self-assembly technique using a poly(styrene sulfonate sodium salt (PSS and poly(allylamine hydrochloride (PAH polyelectrolyte system. Solid diffuse reflectance (SDR studies showed a linear increase in absorbance at 416 nm with increase in the number of m-TiO2 thin films. The LbL assembled thin films were tested for their photocatalytic activity through the degradation of Rhodamine B under visible-light illumination. From the scanning electron microscope (SEM, the thin films had a porous morphology and the atomic force microscope (AFM studies showed “rough” surfaces. The porous and rough surface morphology resulted in high surface areas hence the high photocatalytic degradation (up to 97% over a 6.5 h irradiation period using visible-light observed. Increasing the number of multilayers deposited on the glass slides resulted in increased film thickness and an increased rate of photodegradation due to increase in the availability of more nanocatalysts (more sites for photodegradation. The LbL assembled thin films had strong adhesion properties which made them highly stable thus displaying the same efficiencies after five (5 reusability cycles.

  13. Magnesium and cadmium in covalently bonded networks. Synthesis and structure of AETMg and AETCd (AE = Ca, Sr; T = Pd, Ag, Pt, Au) with TiNiSi type structure and the solid solution Yb{sub 2-x}PtMg{sub x}

    Energy Technology Data Exchange (ETDEWEB)

    Kersting, Marcel; Johnscher, Michael; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2013-07-01

    The equiatomic intermetallic compounds AETMg and AETCd (AE = Ca, Sr; T = Pd, Ag, Pt, Au) and the whole solid solution Yb{sub 2-x}PtMg{sub x} were synthesized from the elements in sealed niobium tubes in a high-frequency or a muffle furnace. All samples were characterized on the basis of their powder X-ray diffraction patterns. The structures of SrAuCd, CaPdCd, CaPtCd, CaPdMg, SrPtMg, CaAg{sub 1.017}Mg{sub 0.983}, SrAg{sub 1.032}Mg{sub 0.968}, and Yb{sub 1.792}PtMg{sub 0.208} were refined on the basis of single-crystal X-ray diffractometer data. Some of the crystals showed small homogeneity ranges. All compounds crystallize with the orthorhombic TiNiSi type structure, space group Pnma. The crystal chemistry is briefly discussed and variations in chemical bonding as a result of the electronegativity of the transition metal are described. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Ilias, Shamsuddin; Kumar, Dhananjay

    2012-07-31

    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

  15. B-Site Metal (Pd, Pt, Ag, Cu, Zn, Ni Promoted La1−xSrxCo1−yFeyO3–δ Perovskite Oxides as Cathodes for IT-SOFCs

    Directory of Open Access Journals (Sweden)

    Shaoli Guo

    2015-03-01

    Full Text Available Perovskite oxides La1−xSrxCo1−yFeyO3–δ (LSCF have been extensively investigated and developed as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs due to mixed ionic–electronic conductivity and high electrooxygen reduction activity for oxygen reduction. Recent literature investigations show that cathode performances can be improved by metal surface modification or B-site substitution on LSCF. Although the specific reaction mechanism needs to be further investigated, the promoting effect of metal species in enhancing oxygen surface exchange and oxygen bulk diffusion is well recognized. To our knowledge, no previous reviews dealing with the effect of metal promotion on the cathodic performances of LSCF materials have been reported. In the present review, recent progresses on metal (Pd, Pt, Ag, Cu, Zn, Ni promotion of LSCF are discussed focusing on two main aspects, the different synthesis approaches used (infiltration, deposition, solid state reaction, one pot citrate method and the effects of metal promotion on structural properties, oxygen vacancies content and cathodic performances. The novelty of the work lies in the fact that the metal promotion at the B-site is discussed in detail, pointing at the effects produced by two different approaches, the LSCF surface modification by the metal or the metal ion substitution at the B-site of the perovskite. Moreover, for the first time in a review article, the importance of the combined effects of oxygen dissociation rate and interfacial oxygen transfer rate between the metal phase and the cathode phase is addressed for metal-promoted LSCF and compared with the un-promoted oxides. Perspectives on new research directions are shortly given in the conclusion.

  16. Photoelectrochemical properties of palladium sulfide (PdS)

    Energy Technology Data Exchange (ETDEWEB)

    Macia, M.D.; Diaz-Chao, P.; Clamagirand, J.; Ares, J.R.; Ferrer, I.J.; Sanchez, C. [UAM, Madrid (Spain). Laboratoria de Materiales de Interes en Energias Renovables

    2010-07-01

    The electrochemical behaviour of PdS films has been studied in 1M Na{sub 2}SO{sub 3} solution. Photoelectrochemical characterization of polycrystalline PdS thin films have been carried out in the potential range -200mVAg/AgCl). The onset of the photocurrent is observed at OV (Ag/AgCl). The photocurrent obtained has been compared with the optical absorption curve and two photocurrent maxima at about 1.6 and 2.1 eV have been identified, the one at higher photon energy is related with the material band gap. (orig.)

  17. Spectroscopy of {sup 96}Ag.

    Energy Technology Data Exchange (ETDEWEB)

    Boutachkov, P.; Gorska, M.; Grawe, H.; Pietri, S.; Pardo, C.D.; Farinon, F.; Kojouharov, I.; Kurz, N.; Nociforo, C.; Prochazka, A.; Prokopowicz, W.; Caceres, L.; Engert, T.; Gerl, J.; Goel, N.; Schaffner, H.; Weick, H.; Wollersheim, H.J.; Merchant, E. [GSI (Germany); Braun, N.; Blazhev, A.; Bettermann, L.; Finke, F.; Geibel, K.; Ilie, G.; Iwasaki, H.; Reiter, P.; Scholl, C.; Warr, N. [Univ. Koeln (Germany); Brock, T.; Nara Singh, B.S.; Wadsworth, R. [Univ. York (United Kingdom); Liu, Z.; Gottardo, A.; Woods, P. [Univ. Edinburgh (United Kingdom); Faestermann, T.; Eppinger, K.; Hinke, C.; Kruecken, R. [TU Munich (Germany); Grebosz, J. [Inst. Fizyki, Krakow (Poland); Podolyak, Zs.; Steer, S.; Regan, P. [Univ. Surrey (United Kingdom); Hoischen, R. [GSI (Germany); Lund Univ. (Sweden); Nyberg, J.; Soederstroem, P.A. [Uppsala Univ. (Sweden); Pfuetzner, M. [Warsaw Univ. (Poland); Rinta-Antila, S. [Univ. Liverpool (United Kingdom); Rudolph, D. [Lund Univ. (Sweden); Atac, A. [Ankara Univ. (Turkey)

    2010-07-01

    A measurement with the RISING setup at the GSI-FRS facility has been performed to study isomer and {beta} decays in N{proportional_to}Z Cd, Ag and Pd isotopes. This study provides information on the shell evolution around the N=Z=50 shell closure. In particular, three new isomeric states were observed in {sup 96}Ag, extending the level scheme to high-spin spherical structures, including core-excited states. A comparison to shell-model calculations ascertains the {sup 100}Sn shell gap from this data. The new {sup 96}Ag results are presented.

  18. Influence of Pressboard Aging on PD Pulse Parameters

    Institute of Scientific and Technical Information of China (English)

    LI Jun-hao; WANG Song; JIN Wei; LI Yan-ming

    2011-01-01

    Combination of pressboard and mineral oil continues to be the choice of materials used as the insulation die- lectric media in large transformers. The purpose of the reported study is to investigate the influence of pressboard ag- ing on PD (partial discharge) pulse parameters. Ultra wide band (UWB) time-resolved PD pulse measurements were carried out on gas void inside pressboard. The rise rime, full time and width time of PD pulse in different aging degree pressboard are obtained. The result is helpful to better understanding the influence of the aging of pressboard on PD measurement and insulation diagnostics in power transformers.

  19. Understanding Pd-Pd bond length variation in (PNP)Pd-Pd(PNP) dimers.

    Science.gov (United States)

    Walensky, Justin R; Fafard, Claudia M; Guo, Chengyun; Brammell, Christina M; Foxman, Bruce M; Hall, Michael B; Ozerov, Oleg V

    2013-03-04

    Analysis of the structures of three (PNP)Pd-Pd(PNP) dimers [where PNP stands for anionic diarylamido/bis(phosphine) pincer ligands] has been carried out with the help of single-crystal X-ray diffractometry and density functional theory (DFT) calculations on isolated molecules. The three dimers under study possess analogous ancillary ligands; two of them differ only by an F versus Me substituent in a remote (five bonds away from Pd) position of the pincer ligand. Despite these close similarities, X-ray structural determinations revealed two distinct structural motifs: a highly symmetric molecule with a long Pd-Pd bond or a highly distorted molecule with Pd-Pd bonds ca. 0.14 Å shorter. DFT calculations on a series of (PNP)Pd-Pd(PNP) dimers (as molecules in the gas phase) confirmed the existence of these distinct minima for dimers carrying large isopropyl substituents on the P-donor atoms (as in the experimental structure). These minima are nearly isoergic conformers. Evidently, the electronically preferred symmetric structure for the dimer (with a square-planar environment about Pd and a linear N-Pd-Pd-N vector) is not sterically possible with the preferred Pd-Pd distance. Thus, the minima correspond to either a symmetric structure with a long Pd-Pd bond distance or a structure with a short Pd-Pd distance but with substantial distortions in the Pd coordination environment to alleviate steric conflict. This notion is supported by finding only a single minimum (symmetric and with short Pd-Pd bonds) for each of the dimers carrying smaller substituents (H or Me) on the P atoms, regardless of the remote substitution.

  20. Effect of electromigration on interfacial reaction in Ni/Sn3.0Ag0.5Cu/Au/Pd/Ni-P flip chip solder joints%电迁移对Ni/Sn3.0Ag0.5Cu/Au/Pd/Ni—P倒装焊点界面反应的影响

    Institute of Scientific and Technical Information of China (English)

    黄明亮; 陈雷达; 周少明; 赵宁

    2012-01-01

    本文研究了150℃,1.0×104A/cm2条件下电迁移对Ni/Sn3.0Ag0.5Cu/Au/Pd/Ni-P倒装焊点界面反应的影响.回流后在solder/Ni和solder/NiP的界面上均形成(Cu,Ni)6Sn5类型金属间化合物.时效过程中两端界面化合物都随时间延长而增厚,且化合物类型都由(Cu,Ni)6Sn5转变为(Ni,Cu)3Sn4.电迁移过程中电子的流动方向对Ni—P层的消耗起着决定性作用.当电子从基板端流向芯片端时,电迁移促进了Ni—P层的消耗,600h后阴极端Ni-P层全部转变为Ni2SnP层.阴极界面处由于Ni2SnP层的存在,使界面Cu-Sn—Ni三元金属间化合物发生电迁移脱落溶解,而且由于Ni2SnP层与Cu焊盘的结合力较差,在Ni2SnP/Cu界面处会形成裂纹.当电子从芯片端流向基板端时,阳极端Ni—P层并没有发生明显的消耗.电流拥挤效应导致了阴极芯片端Ni层和Cu焊盘均发生了局部快速溶解,溶解到钎料中的Cu和Ni原子沿电子运动的方向往阳极运动并在钎料中形成了大量的化合物颗粒.电迁移过程中(Au,Pd,Ni)Sn4的聚集具有方向性,即(Au,Pd,Ni)Sn4因电流作用而在阳极界面处聚集.%The effect of electromigration (EM) on the interracial reaction in the Ni/Sn3.0Ag0.5Cu/Au/Pd/Ni-P flip chip solder joint is investigated under a current density of 1.0 ×104 A/cm2 at 150℃. The (Cu,Ni)6Sn5 intermetallic compounds (IMCs) form at both solder/Ni and solder/Ni-P interfaces in the as-reflowed state. During aging at 150℃, the (Cu,Ni)6Sn5 interfacial IMCs grow thicker and transform into (Ni,Cu)3Sn4 type after 200 h at solder/Ni interface and 600 h at solder/Ni-P interface, respectively. During EM, the current direction plays an important role in Ni-P layer consumption. When electrons flow from Ni-P to Ni, EM enhances the consumption of Ni-P, i.e., the Ni-P s completely consumed and transforms into Ni2SnP after EM for 600 h. There is

  1. Factorial PD-Clustering

    CERN Document Server

    Tortora, Cristina; Summa, Mireille Gettler

    2011-01-01

    Factorial clustering methods have been developed in recent years thanks to the improving of computational power. These methods perform a linear transformation of data and a clustering on transformed data optimizing a common criterion. Factorial PD-clustering is based on Probabilistic Distance clustering (PD-clustering). PD-clustering is an iterative, distribution free, probabilistic, clustering method. Factorial PD-clustering make a linear transformation of original variables into a reduced number of orthogonal ones using a common criterion with PD-Clustering. It is demonstrated that Tucker 3 decomposition allows to obtain this transformation. Factorial PD-clustering makes alternatively a Tucker 3 decomposition and a PD-clustering on transformed data until convergence. This method could significantly improve the algorithm performance and allows to work with large dataset, to improve the stability and the robustness of the method.

  2. Synthesis and biological activity of Cu(II),Ag(I), Cd(II)and Pd(II)complexes of betulinal thiosemicarbazone%桦木醛缩氨基硫脲铜、银、镉、钯金属配合物的合成及其生物活性研究

    Institute of Scientific and Technical Information of China (English)

    林汉; 刘颖; 朴凤玉; 韩荣弼

    2016-01-01

    Using combination principle,two betulinal thiosemicarbazone ligands and their Cu(II),Ag(I),Cd (II)and Pd(II)metal complexes were synthesized,which were characterized by IR,1 H NMR,TGA,MAL-DI-TOF and elemental analysis.The ligands and their metal complexes were evaluated for their antimicrobial activity and cytotoxicity.The results showed that the complex Ag (L1 )2 NO3 ·3H2 O has relatively good inhibitory effects on S.aureus 4220,S.mutans 3065 and E.coli 1924.Complexes Ag(L1 )2 NO3·3H2 O and Cu(L1 )2 Cl2 can significantly inhibit the viability of Hela cell.%运用拼合原理,合成了2种桦木醛缩氨基硫脲配体以及它们的铜、银、镉、钯金属配合物,运用红外光谱、核磁共振氢谱、热重分析、飞行质谱和元素分析方法对其进行了结构表征,并测试了配体和配合物的抑菌活性和细胞毒性.结果表明:配合物 Ag(L1)2 NO3·3H2 O 对 S.aureus 4220、S.mutans 3065和 E.coli 1924有较好的抑制作用;配合物 Ag(L1)2 NO3·3H2 O 和 Cu(L1)2 Cl2能够显著抑制 Hela 细胞的生存能力.

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

    Energy Technology Data Exchange (ETDEWEB)

    Poudel, L.; de la Cruz, C.; Payzant, E. A.; May, A. F.; Koehler, M.; Garlea, V. O.; Taylor, A. E.; Parker, D. S.; Cao, H. B.; McGuire, M. A.; Tian, W.; Matsuda, M.; Jeen, H.; Lee, H. N.; Hong, T.; Calder, S.; Zhou, H. D.; Lumsden, M. D.; Keppens, V.; Mandrus, D.; Christianson, A. D.

    2015-12-15

    The structural and the magnetic properties of CeCu6-xAgx (0≤x≤0.85) and CeCu6-xPdx (0≤x≤0.4) have been studied using neutron diffraction, resonant ultrasound spectroscopy (RUS), x-ray diffraction measurements, and first principles calculations. The structural and magnetic phase diagrams of CeCu6-xAgx and CeCu6-xPdx as a function of Ag/Pd composition are reported. The end member, CeCu6, undergoes a structural phase transition from an orthorhombic (Pnma) to a monoclinic (P21/c) phase at 240 K. In CeCu6-xAgx, the structural phase transition temperature (Ts) decreases linearly with Ag concentration and extrapolates to zero at xS ≈0.1. The structural transition in CeCu6-xPdx remains unperturbed with Pd substitution within the range of our study. The lattice constant b slightly decreases with Ag/Pd doping, whereas a and c increase with an overall increase in the unit cell volume. Both systems, CeCu6-xAgx and CeCu6-xPdx, exhibit a magnetic quantum critical point (QCP), at x≈0.2 and x≈0.05, respectively. Near the QCP, long range antiferromagnetic ordering takes place at an incommensurate wave vector (δ10 δ2), where δ1~0.62,δ2~0.25,x=0.125 for CeCu6-xPdx and δ1~0.64,δ2~0.3,x=0.3 for CeCu6-xAgx. The magnetic structure consists of an amplitude modulation of the Ce moments which are aligned along the c axis of the orthorhombic unit cell.

  4. Development of membranes for hydrogen separation: Pd-coated V-10Pd

    Energy Technology Data Exchange (ETDEWEB)

    Paglieri, Stephen N [Los Alamos National Laboratory; Wermer, Joseph R [Los Alamos National Laboratory; Buxbaum, Robert E [REB RESEARCH AND CONSULTING; Ciocco, Michael V [NETL; Howard, Bret H [NETL; Morreale, Bryan D [NETL

    2009-01-01

    Numerous Group IVB and VB alloys were prepared and tested as potential membrane materials but most of these materials were brittle or exhibited cracking during hydrogen exposure. One of the more ductile alloys, V-10Pd (at. %), was fabricated into a thin (107-{micro}m thick) composite membrane coated with 100 nm of Pd on each side. The material was tested for hydrogen permeability, resistance to hydrogen embrittlement, and long term hydrogen flux stability. The hydrogen permeability, {phi}, of the V-10Pd membrane was 3.86 x 10{sup -8} mol H{sub 2} m{sup -1} s{sup -1} Pa{sup -0.5} (avg. of three different samples) at 400 C, which is slightly higher than the permeability of Pd-23Ag at that temperature. A 1400 h hydrogen flux test at 400 C demonstrated that the rate of metallic interdiffusion was slow between the V-10Pd foil and the 100-nm-thick Pd coating on the surface. However, at the end of testing the membrane cracked at 118 C because of hydrogen embrittlement.

  5. Universal chitosan-assisted synthesis of Ag-including heterostructured nanocrystals for label-free in situ SERS monitoring.

    Science.gov (United States)

    Cai, Kai; Xiao, Xiaoyan; Zhang, Huan; Lu, Zhicheng; Liu, Jiawei; Li, Qin; Liu, Chen; Foda, Mohamed F; Han, Heyou

    2015-12-07

    A universal chitosan-assisted method was developed to synthesize various Ag-including heterostructured nanocrystals, in which chelation probably plays a vital role. The as-prepared Ag/Pd heterostructured nanocrystals show outstanding properties when used as bifunctional nanocomposites in label-free in situ SERS monitoring of Pd-catalyzed reaction.

  6. The PD-1/PD-Ls pathway and autoimmune diseases.

    Science.gov (United States)

    Dai, Suya; Jia, Ru; Zhang, Xiao; Fang, Qiwen; Huang, Lijuan

    2014-07-01

    The programmed death (PD)-1/PD-1 ligands (PD-Ls) pathway, is a new member of the B7/CD28 family, and consists of the PD-1 receptor and its ligands PD-L1 (B7-H1, CD274) and PD-L2 (B7-DC, CD273). Recently, it is reported that PD-1, PD-L1 and PD-L2 also have soluble forms aside from their membrane bound forms. The soluble forms increase the diversity and complexity of PD-1/PD-Ls pathway in both composition and function. The PD-1/PD-Ls pathway is broadly expressed and exerts a wider range of immunoregulatory roles in T-cell activation and tolerance compared with other B7/CD28 family members. Studies show that the PD-1/PD-Ls pathway regulates the induction and maintenance of peripheral tolerance and protects tissues from autoimmune attack in physiological conditions. In addition, it is also involved in various diseases mediated by T cells, such as autoimmunity, tumor immunity, chronic viral infections, and transplantation immunity. In this review, we will summarize the relevance of the soluble forms and the latest researches on the role of PD-1/PD-Ls pathway in autoimmune diseases.

  7. Thermal- and pressure-induced cooperative spin transition in the 2D and 3D coordination polymers {Fe(5-Br-pmd)z[M(CN)x]y} (M=AgI, AuI, NiII, PdII, PtII).

    Science.gov (United States)

    Agustí, Gloria; Gaspar, Ana Belén; Muñoz, M Carmen; Real, José Antonio

    2007-11-12

    A new family of cyanide-based spin-crossover polymers with the general formula {Fe(5-Br-pmd)z[M(CN)x]y} [M=AgI (1), AuI (2), NiII (3), PdII (4), PtII (5); 5-Br-pmd=5-bromopyrimidine; z=1 or 2, x=2 or 4, and y=2 or 1] have been synthesized and characterized using single-crystal X-ray diffraction (XRD), X-ray powder diffraction (XRPD), magnetic susceptibility measurements, and differential scanning calorimetry (DSC). At 293 K, compound 1 presents the monoclinic space group C2/c, whereas at 120 K, it changes to the monoclinic space group P21/c. At 293 K, the crystal structure of 1 displays an uninodal three-dimensional network whose nodes, constituted of FeII, lie at the inversion center of an elongated octahedron. The equatorial bond lengths are defined by the N atoms of four [AgI(CN)2]- groups belonging to two crystallographically nonequivalent AgI atoms, Ag(1) and Ag(2). They are shorter than those of the axial positions occupied by the N atoms of the 5-Br-pmd ligands. The Fe-N average bond length of 2.1657(7) A is consistent with a high-spin (HS) state for the FeII ions. At 120 K, the crystal structure changes refer mainly to the FeII environment. There are two crystallographically independent FeII ions at this temperature, Fe(1) and Fe(2), which adopt the HS and low-spin (LS) states, respectively. The average Fe-N bond length for Fe(1) [2.174(5) A] and Fe(2) [1.955(5) A] agrees well with the reported magnetic data at this temperature. The spin transition of the FeII ions labeled as Fe(1) is found to be centered at Tc downward arrow=149 K and Tc upward arrow=167 K and accompanied by a drastic change of color from orange (HS) to red (LS). Magnetic susceptibility measurements under applied hydrostatic pressure performed on 1 have shown a linear displacement of the transition to higher temperatures while the hysteresis width remains unaltered in the interval of pressures of 105 Pa to 0.34 GPa. A further increase of the pressure induces the spin transition in the Fe(2

  8. Electrochemical and surface studies on the passivity of a dental Pd-based casting alloy in alkaline sulphide solution

    Energy Technology Data Exchange (ETDEWEB)

    Endo, Kazuhiko; Ohno, Hiroki; Matsuda, Koichi; Asakura, Shukuji

    2003-07-01

    The corrosion and tarnish behavior of a dental casting Pd-25Ag-18Cu-12Au alloy in 0.1% Na{sub 2}S solution at 37 deg. C was investigated using potentiodynamic polarization and spectrocolorimetric techniques. The surface film was characterized by X-ray photoelectron spectroscopy (XPS). This alloy exhibited markedly higher resistance to corrosion and tarnish than did the Ag-20Pd-18Cu-12Au alloy in current clinical use. XPS spectra indicated the presence of a thin sulphide film composed of PdS. It was found that the PdS film is very protective and is responsible for the passivity of the Pd-25Ag-18Cu-12Au alloy in 0.1% Na{sub 2}S solution.

  9. Low temperature magnetic properties of DyPdBi

    Science.gov (United States)

    Mukhopadhyay, A.; Chowki, S.; Mohapatra, N.

    2016-05-01

    We report the results of dc magnetization measurements in the ternary half -Heuslar alloy, DyPdBi which crystallizes in a non centrosymmetric MgAgAs type fcc structure. DyPdBi undergoes a long range antiferromagnetic type ordering below 4.0 K as inferred from the temperature dependence of dc magnetic susceptibility. Another noteworthy observation is the field induced metamagnetic transition below TN, further suggestes that the order-order field induced transition as a first order phase transition.

  10. Influence of cryogenic treatment and age-hardening heat treatment on the corrosion behavior of a dental casting Ag-Pd alloy%不同热处理对牙科铸造银钯合金腐蚀行为的影响

    Institute of Scientific and Technical Information of China (English)

    赵耀; 武斌; 孟玉坤

    2014-01-01

    Objective The purpose of this study is to investigate the influence of cryogenic treatment and age-hardening heat treatment on the corrosion behavior of a dental casting Ag-Pd alloy. Methods A low gold content dental casting alloy composed of Ag-Pd-Cu-Au was prepared for this study. Corrosion test was performed according to ISO 10271:2001 dental metalliecorrosion test methods. Experimental specimens were casted according to a standard dental lost-wax casting procedure, treated with solution by heating the specimens to 900 ℃, and immediately quenched in ice water. The specimens were then divided into four groups and subjected to heat treatment, cryogenic treatment, and heat treatment combined with cryogenic treatment. The specimens after the solution treatment were taken as control. The metallographic structures of the specimens were observed. The electrochemical parameters and the quantity of non-precious metallic ions released were evaluated via electrochemical and static immersion tests. Results Metallographic observation revealed that all the treatments resulted in a change in the microstructure of the alloy. The treatments were effective in improving the electrochemical parameters, such as an increase in Eocp and Ecorr and a decrease in Icorr (P0.05). Conclusion After different treatments, the antierosion properties of the alloy satisfied the ISO requirements. Age-hardening heat treatment and cryogenic treatment improved the corrosion resistance of the alloy.%目的:研究不同处理对牙科用银钯铸造合金腐蚀行为的影响。方法熔炼银钯铸造合金,参照ISO10271:2001牙科金属材料抗腐蚀实验标准,按照标准牙科失蜡法铸造程序制作测试样本,经固溶软化处理后,分别进行相应的热处理、深冷处理、热处理并深冷处理,以固溶软化处理组作为对照组。采用金相显微镜观察分析,并行电化学实验、静态浸泡实验测试合金的电化学参数及非贵金属离

  11. Longitudinal fluctuations in PD1 and PD-L1 expression in association with changes in anti-viral immune response in chronic hepatitis B

    Directory of Open Access Journals (Sweden)

    Wenjin Zhang

    2012-08-01

    Full Text Available Abstract Background Controversy exists regarding the role of PD1 and its ligand PD-L1 in chronic hepatitis B infection. In some studies, persistent HBV infection has been attributed to high levels of PD-1 and PD-L1 expression on HBV-specific T-cells and antigen-presenting cells (APCs respectively. Other studies revealed that the up-regulation of PD-1 and PD-L1 during an acute inflammation phase is required to offset increasing positive co-stimulatory signals to avoid severe damage by an over-vigorous immune response. Methods Fifteen chronic hepatitis B patients, with inflammatory flare episode, were recruited prospectively. Based on serum HBV-DNA, HBsAg load, and ALT values, inflammatory flare episode were divided into initial, climax, decline and regression phase. Blood sample and liver biopsy tissues from each individual were taken in these 4 phases respectively. Circulating and intra-hepatic PD1 and PD-L1 expression levels were monitored throughout the inflammatory flare episode by flow cytometry and immunostaining and these expression levels were related to the HBV-specific T-cell changes, expression of pro-inflammatory cytokines, HBV-DNA replication and HBV antigen load. Results ]The levels of PD-1 and PD-L1 expressions were significantly up-regulated in the inflammation ascending phase, initial and climax period and in parallel with HBV-specific colon expansion. It showed increasing the level of serum ALT and decreasing the HBV-DNA loads. As the level of inflammation reduced, the circulating and intra-hepatic PD1 and circulating PD-L1 decreased progressively in concordance with serum ALT, HBV-DNA and HBsAg loads decreased except intra-hepatic PD-1 expression. Intra-hepatic PD-L1 expression did not decrease significantly during the regression phase of inflammation compared to that in prior period. The intra-hepatic PD-L1 expression remained relatively on higher level when serum HBV-DNA load and ALT decreased to approximately normal range

  12. PD-1 Blockers.

    Science.gov (United States)

    Wolchok, Jedd D

    2015-08-27

    Nivolumab and pembrolizumab are monoclonal antibodies that block the programmed death-1 receptor (PD-1, CD279), resulting in dis-inhibition of tumor-specific immune responses. Both are recently approved for use in the treatment of metastatic melanoma, and nivolumab as well for non-small cell lung cancer.

  13. Synthesis and Characterization of a Triphos Ligand Derivative and the Corresponding Pd II Complexes: Triphos Ligand Derivative and Corresponding Pd II Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Deanna L.; Boro, Brian J.; Grubel, Katarzyna; Helm, Monte L.; Appel, Aaron M.

    2015-11-16

    The synthesis of the new bis(2-(diphenylphosphino)ethyl)methylhydroxyphosphine tridentate phosphine ligand, LCH2OH/Ph, is reported. The ligand reacts with [Pd(Cl)2(PhCN)2 to form [Pd(LCH2OH/Ph)Cl]Cl. Exchange of the chloride ions for triflate (OTf–) using AgOTf yielded pure [Pd(LCH2OH/Ph)OTf]OTf. In addition to spectral characterization the free ligand, LCH2OH/Ph, and Pd(II) complex, [Pd(LCH2OH/Ph)OTf]OTf, are structurally characterized. This research was supported by the US Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Biosciences, and Geosciences. Pacific Northwest National Laboratory is a multiprogram national laboratory operated by Battelle for DOE.

  14. PD-1, gender, and autoimmunity

    Science.gov (United States)

    Dinesh, Ravi K.; Hahn, Bevra H.; Singh, Ram Pyare

    2010-01-01

    Programmed death 1 (PD-1) and its ligands (PD-L1 and PD-L2) are responsible for inhibitory T cell signaling that helps mediate the mechanisms of tolerance and immune homeostasis. The PD-1:PD-L signaling pathway has been shown to play an important role in a variety of diseases, including autoimmune conditions, chronic infection, and cancer. Recently, investigators have explored the role of sex hormones in modulating the pathway in autoimmune conditions. Exploring the effects of sex hormones on the PD-1:PD-L pathway could shed light on the gender biased nature of many autoimmune conditions as well as aide in the development of therapeutics targeting the immune system. PMID:20433954

  15. Size-controlled Pd Nanoparticles Supported onα-Al2O3 as Heterogeneous Catalyst for Selective Hydrogenation of Acetylene

    Institute of Scientific and Technical Information of China (English)

    张火利; 杨元一; 戴伟; 鲁树亮; 于海波; 吉媛媛

    2014-01-01

    Size-controlled Pd nanoparticles (PdNPs) were synthesized in aqueous solution, using sodium car-boxymethyl cellulose as the stabilizer. Size-controlled PdNPs were supported onα-Al2O3 by the incipient wetness impregnation method. The PdNPs onα-Al2O3 support were in a narrow particle size distribution in the range of 1-6 nm. A series of PdNPs/α-Al2O3 catalysts were used for the selective hydrogenation of acetylene in ethylene-rich stream. The results show that PdNPs/α-Al2O3 catalyst with 0.03%(by mass) Pd loading is a very effective and sta-ble catalyst. With promoter Ag added, ethylene selectivity is increased from 41.0%to 63.8%at 100 °C. Comparing with conventional Pd-Ag/α-Al2O3 catalyst, PdNPs-Ag/α-Al2O3 catalyst has better catalytic performance in acety-lene hydrogenation and shows good prospects for industrial application.

  16. Cross section measurements of the sup 1 sup 0 sup 2 Pd(p, gamma) sup 1 sup 0 sup 3 Ag, sup 1 sup 1 sup 6 Sn(p, gamma) sup 1 sup 1 sup 7 Sb, and sup 1 sup 1 sup 2 Sn(alpha, gamma) sup 1 sup 1 sup 6 Te reactions relevant to the astrophysical rp- and gamma-processes

    CERN Document Server

    Oezkan, N; Boyd, R N; Cole, A L; Famiano, M; Gueray, R T; Howard, M; Sahin, L; Zach, J J; Haan, R D; Görres, J; Wiescher, M C; Islam, M S; Rauscher, T

    2002-01-01

    Total cross section measurements for the sup 1 sup 0 sup 2 Pd(p, gamma) sup 1 sup 0 sup 3 Ag and sup 1 sup 1 sup 6 Sn(p, gamma) sup 1 sup 1 sup 7 Sb reactions have been performed in the proton energy range 2.6 to 4.25 MeV, and for the sup 1 sup 1 sup 2 Sn(alpha, gamma) sup 1 sup 1 sup 6 Te reaction over the alpha beam energy range 7.0 to 10.5 MeV. An activation technique was used in which gamma rays from decays of the reaction products were detected off-line by two hyper-pure germanium detectors in a low background environment. Where possible, reaction rates are derived and the results compared to those of calculations generated by the NON-SMOKER and the MOST statistical model codes so as to judge their applicability for describing the cross sections needed for network calculations of nucleosynthesis in explosive astrophysical environments via the gamma- and rp-processes.

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

    Science.gov (United States)

    Benn, Raymond C.; Opalka, Susanne M.; Vanderspurt, Thomas Henry

    2010-02-02

    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.

  18. Distinct metal-exchange pathways of doped Ag25 nanoclusters

    KAUST Repository

    Bootharaju, Megalamane Siddaramappa

    2016-09-09

    Atomically precise metal nanoclusters (NCs) containing more than one type of metal atom (i.e., doped or alloyed), due to synergistic effects, open new avenues for engineering the catalytic and optical properties of NCs in a manner that homometal NCs cannot. Unfortunately, it is still a major challenge to controllably introduce multimetallic dopants in NCs, understanding the dopants\\' positions, mechanism, and synergistic effects. To overcome these challenges, we designed a metal-exchange approach involving NCs as molecular templates and metal ions as the source of the incoming dopant. In particular, two structurally similar monodoped silver-rich NCs, [MAg24(SR)(18)](2-) (M = Pd/Pt and SR: thiolate), were synthesized as templates to study their mechanistic transformation in response to the introduction of gold atoms. The controllable incorporation of Au atoms into the MAg24 framework facilitated the elucidation of distinct doping pathways through high-resolution mass spectrometry, optical spectroscopy and elemental analysis. Interestingly, gold replaced the central Pd atom of [PdAg24(SR)(18)](2-) clusters to produce predominantly bimetallic [AuAg24(SR)(18)](-) clusters along with a minor product of an [Au2Ag23(SR)(18)](-) cluster. In contrast, the central Pt atom remained intact in [PtAg24(SR)(18)](2-) clusters, and gold replaced the noncentral Ag atoms to form trimetallic [AuxPtAg24-x(SR)(18)](2-) NCs, where x = 1-2, with a portion of the starting [PtAg24(SR)(18)](2-) NCs remaining. This study reveals some of the unusual metal-exchange pathways of doped NCs and the important role played by the initial metal dopant in directing the position of a second dopant in the final product.

  19. Electroless Sliver-Plating Process in the Preparation of 103Pd-125I Hybrid Brachytherapy Seed Cores

    Directory of Open Access Journals (Sweden)

    LI Zhong-yong1,2;CHEN Bin-da1;Lv Xiao-zhou1;LU Jin-hui1;CUI Hai-ping1,2

    2014-02-01

    Full Text Available Electroless 103Pd plating and electroless Ag plating and chemical 125I depositing were took place on the surface of carbon rods in turn, which was a reliable method for the preparation of 103Pd-125I hybrid brachytherapy seed cores. 103Pd and 125I were deposited on the same substrate effectively through silver coating as a bridge. The process of electroless Ag plating was a novel and important step in the preparation of 103Pd-125I hybrid seed. In this work, the process of electroless Ag plating was studied using 0.5×3.0 mm carbon rods with palladium coating as substrate, silver-ammino complex as precursor, 110mAg as radioactive tracer, and hydrazine as reductant. The optimum conditions were AgNO3 2g/L,Na2EDTA 40 g/L,NH3•H2O 16.25%,H4N2•H2O 5‰,pH=10,t=60 min,and T=35 ℃. Sliver deposited on each carbon rod was uniform, and sliver-coating was white and smooth.

  20. CO-induced Pd segregation and the effect of subsurface Pd on CO adsorption on CuPd surfaces

    Science.gov (United States)

    Padama, A. A. B.; Villaos, R. A. B.; Albia, J. R.; Diño, W. A.; Nakanishi, H.; Kasai, H.

    2017-01-01

    We report results of our study on the adsorption of CO on CuPd surfaces with bulk stoichiometric and nonstoichiometric layers using density functional theory (DFT). We found that the presence of Pd atoms in the subsurface layer promotes the adsorption of CO. We also observed CO-induced Pd segregation on the CuPd surface and we attribute this to the strong CO-Pd interaction. Lastly, we showed that the adsorption of CO promotes Pd-Pd interaction as compared to the pristine surface which promotes strong Cu-Pd interaction. These results indicate that CO adsorption on CuPd surfaces can be tuned by taking advantage of the CO-induced segregation and by considering the role of subsurface Pd atoms.

  1. Perpendicular magnetic anisotropy in granular multilayers of CoPd alloyed nanoparticles

    Science.gov (United States)

    Vivas, L. G.; Rubín, J.; Figueroa, A. I.; Bartolomé, F.; García, L. M.; Deranlot, C.; Petroff, F.; Ruiz, L.; González-Calbet, J. M.; Pascarelli, S.; Brookes, N. B.; Wilhelm, F.; Chorro, M.; Rogalev, A.; Bartolomé, J.

    2016-05-01

    Co-Pd multilayers obtained by Pd capping of pre-deposited Co nanoparticles on amorphous alumina are systematically studied by means of high-resolution transmission electron microscopy, x-ray diffraction, extended x-ray absorption fine structure, SQUID-based magnetometry, and x-ray magnetic circular dichroism. The films are formed by CoPd alloyed nanoparticles self-organized across the layers, with the interspace between the nanoparticles filled by the non-alloyed Pd metal. The nanoparticles show atomic arrangements compatible with short-range chemical order of L 10 strucure type. The collective magnetic behavior is that of ferromagnetically coupled particles with perpendicular magnetic anisotropy, irrespective of the amount of deposited Pd. For increasing temperature three magnetic phases are identified: hard ferromagnetic with strong coercive field, soft-ferromagnetic as in an amorphous asperomagnet, and superparamagnetic. Increasing the amount of Pd in the system leads to both magnetic hardness increment and higher transition temperatures. Magnetic total moments of 1.77(4) μB and 0.45(4) μB are found at Co and Pd sites, respectively, where the orbital moment of Co, 0.40(2) μB, is high, while that of Pd is negligible. The effective magnetic anisotropy is the largest in the capping metal series (Pd, Pt, W, Cu, Ag, Au), which is attributed to the interparticle interaction between de nanoparticles, in addition to the intraparticle anisotropy arising from hybridization between the 3 d -4 d bands associated to the Co and Pd chemical arrangement in a L 10 structure type.

  2. Interaction of CO with PtxAg1-x/Pt(111) surface alloys: More than dilution by Ag atoms

    Science.gov (United States)

    Schüttler, K. M.; Mancera, L. A.; Diemant, T.; Groß, A.; Behm, R. J.

    2016-08-01

    We have investigated CO adsorption on structurally well-defined PtxAg1-x/Pt(111) surface alloys, combining temperature-programmed desorption (TPD) and infrared reflection absorption spectroscopy (IRRAS) as well as density functional theory (DFT) based calculations. This is part of a systematic approach including previous studies of CO adsorption on closely related Pt(111)- and Pd(111)-based surface alloys. Following changes in the adsorption properties with increasing Ag content and correlating them with structural changes allow us to assign desorption features to specific adsorption sites/ensembles identified in previous scanning tunneling microscopy (STM) measurements, and thus to identify and separate contributions from different effects such as geometric ensemble effects and electronic ligand/strain effects. DFT calculations give further insight into the nature of the metal-CO bond on these bimetallic sites. Most prominently, the growth of a new CO desorption feature at higher temperature (~ 550 K) in the TPD spectra of Ag-rich surface alloys, which is unique for the group of Pt(111)- and Pd(111)-based surface alloys, is attributed to CO adsorption on Pt atoms surrounded by a Ag-rich neighborhood. Adsorption on these sites manifests in an IR band down-shifted to significantly lower wave number. Systematic comparison of the present results with previous findings for CO adsorption on the related Pt(111)- and Pd(111)-based surface alloys gains a detailed insight into general trends in the adsorption behavior of bimetallic surfaces.

  3. Behavior of intermetallics formation and evolution in Ag–8Au–3Pd alloy wire bonds

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Rui [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai (China); Hang, Tao, E-mail: hangtao@sjtu.edu.cn [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai (China); Mao, Dali [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai (China); Li, Ming, E-mail: mingli90@sjtu.edu.cn [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai (China); Qian, Kaiyou; Lv, Zhong; Chiu, Hope [Packaging RnD and Advanced MFG Engineering, SanDisk Semiconductor (Shanghai) Co., Ltd., Shanghai (China)

    2014-03-05

    Highlights: • Two IMC layers formed between Ag–8Au–3Pd alloy wire and Al pad were identified. • IMCs growth during annealing was discussed by diffusion kinetics. • Ag diffusion controls voids filling at bonding interface during thermal aging. -- Abstract: Ag–8Au–3Pd alloy wire has shown promise as an economical substitute for gold wire interconnects from integrated circuits to substrates. This work is undertaken to gain a better understanding on the intermetallic compounds (IMC) formation and evolution at the interface between Ag–8Au–3Pd wire and Al metallization pad. Longitudinal cross-section of bond interface was prepared by dual-beam focused ion beam (FIB) micro-machining for transmission electron microscopy (TEM) analysis. Two intermetallic regions formed at interface were crystallochemically identified as AuAl{sub 2} + (Au, Ag){sub 4}Al and Ag{sub 2}Al respectively. Interface evolution tracking by back scattered electron (BSE) imaging showed that IMC initially formed at periphery of bonding area. After short-term annealing treatment (175 °C for 24 h), the voids in the center of the bonding interface shrank and vanished, due to the Ag diffusion played dominant part in IMC growing. The mechanism of IMC formation and evolution at interface was finally elaborated on the basis of thermodynamics and diffusion kinetics respectively.

  4. Growth of Pd{sub 4}S, PdS and PdS{sub 2} films by controlled sulfurization of sputtered Pd on native oxide of Si

    Energy Technology Data Exchange (ETDEWEB)

    Bhatt, R., E-mail: rbhatt@barc.gov.in [Technical Physics Division, Bhabha Atomic Research Center, Mumbai–400 085 (India); Bhattacharya, S.; Basu, R.; Singh, A. [Technical Physics Division, Bhabha Atomic Research Center, Mumbai–400 085 (India); Deshpande, U. [UGC–DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore–452017 (India); Surger, C. [Karlsruhe Institute of Technology, Physikalisches Institut and DFG Center for Functional Nanostructures, P.O. Box 6980, D–76049 Karlsruhe (Germany); Basu, S. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400 085 (India); Aswal, D.K.; Gupta, S.K. [Technical Physics Division, Bhabha Atomic Research Center, Mumbai–400 085 (India)

    2013-07-31

    Thin films of different Pd–S phase, namely Pd{sub 4}S, PdS and PdS{sub 2}, have been reproducibly grown by the sulfurization of Pd films deposited on native oxide of (111) Si substrates by radio frequency sputtering method. In order to achieve controlled sulfurization, a three-stage sulfurization setup consisting of evaporation chamber, activation chamber and sulfurization chamber has been developed. The sulfurization of Pd films (kept at a constant temperature of 500 °C) was carried out using sulfur vapors activated to different temperature between 550 and 700 °C. The results of X-ray diffraction and X-ray photoelectron spectroscopy measurements show that formation of Pd{sub 4}S, PdS and PdS{sub 2} phases takes place for the activation temperatures of 550, 600 and 700 °C, respectively. The room temperature resistivity of Pd, Pd{sub 4}S, PdS and PdS{sub 2} were found to be respectively 0.1, 15.9, 15,000 and 20,000 μΩ cm. The temperature-dependent electrical resistivity measurements showed metallic conduction for Pd and Pd{sub 4}S films. The Seebeck coefficient measured at 300 K for these Pd–S phases showed their n-type conducting behavior. - Highlights: • Multichamber sulfurization setup designed for preparing thin films of Pd–S. • S vapor activated at 550, 600 and 700 °C results in Pd{sub 4}S, PdS and PdS{sub 2} phases. • The Seebeck coefficient of Pd–S phases shows their n-type conducting behavior. • Transport properties of Pd{sub 4}S phase show that it is a metallic phase. • High resistivity and thermopower of PdS and PdS{sub 2} show semiconducting nature.

  5. AGS experiments - 1994, 1995, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1997-01-01

    This report contains the following information on the Brookhaven AGS Accelerator complex: FY 1996 AGS schedule as run; FY 1997 AGS schedule (working copy); AGS beams 1997; AGS experimental area FY 1994 physics program; AGS experimental area FY 1995 physics program; AGS experimental area FY 1996 physics program; AGS experimental area FY 1997 physics program (in progress); a listing of experiments by number; two-phage summaries of each experiment begin here, also ordered by number; listing of publications of AGS experiments begins here; and listing of AGS experimenters begins here.

  6. Mass measurements and implications for the energy of the high-spin isomer in 94Ag

    CERN Document Server

    Kankainen, A; Batist, L; Eliseev, S; Eronen, T; Hager, U; Hakala, J; Jokinen, A; Moore, I D; Novikov, Yu N; Pentillä, H; Popov, A; Rahaman, S; Rinta-Antila, S; Rissanen, J; Saastamoinen, A; Seliverstov, D M; Sonoda, T; Vorobjev, G; Weber, C; Äystö, J

    2008-01-01

    Nuclides in the vicinity of 94Ag have been studied with the Penning trap mass spectrometer JYFLTRAP at IGISOL. The masses of the two-proton decay daughter 92Rh and the beta-decay daughter 94Pd of the high-spin isomer in 94Ag have been measured and the masses of 93Pd and 94Ag have been deduced. When combined with the data from the one-proton or two-proton decay experiments, the results lead to contradictory mass excess values for the high-spin isomer in 94Ag, -46370(170) keV or -44970(100) keV, corresponding to excitation energies of 6960(400) keV or 8360(370) keV, respectively.

  7. Pd segregation to the surface of Au on Pd(111) and on Pd/TiO2(110)

    Science.gov (United States)

    Sharpe, Ryan; Counsell, Jon; Bowker, Michael

    2017-02-01

    The interaction of Au and Pd in bimetallic systems is important in a number of areas of technology, especially catalysis. In order to investigate the segregation behaviour in such systems, the interaction of Pd and Au was investigated by surface science methods. In two separate sets of experiments, Au was deposited onto a Pd(111) single crystal, and Pd and Au were sequentially deposited onto TiO2(110), all in ultra-high vacuum using metal vapour deposition. Heating Au on Pd/TiO2(110) to 773 K resulted in the loss of the Au signal in the LEIS, whilst still remaining present in the XPS, due to segregation of Pd to the surface and the formation of a Au-Pd core-shell structure. It is likely that this is due to alloying of Au with the Pd and surface dominance of that alloy by Pd. The Au:Pd XPS peak area ratio is found to substantially decrease on annealing Au/Pd(111) above 773 K, corresponding with a large increase in the CO sticking probability to that for clean Pd(111). This further indicates that Au diffuses into the bulk of Pd on annealing to temperatures above 773 K. It therefore appears that Au prefers to be in the bulk in these systems, reflecting the exothermicity of alloy formation.

  8. Nitrate reduction in water: influence of the addition of a second metal on the performances of the Pd/CeO(2) catalyst.

    Science.gov (United States)

    Devadas, Abirami; Vasudevan, Subramanyan; Epron, Florence

    2011-01-30

    An attempt is made to improve the catalytic nitrate reduction on Pd/CeO(2) catalysts by the addition of a second metal. The influence of the second metal such as Sn, In and Ag on the Pd/CeO(2) for nitrate reduction is explored. The second metal is introduced over monometallic Pd/CeO(2) by a redox reaction. Pd/CeO(2) is more active than the bimetallic catalysts under pure hydrogen flow. Whereas in presence of CO(2) the monometallic Pd/CeO(2) is inactive for nitrate reduction, bimetallic catalysts are found to be more active than under pure hydrogen flow and also than the monometallic catalyst with a low selectivity towards ammonium ions, undesired product of the reaction. The Pd-Sn/CeO(2) catalyst is comparatively the most suited for nitrate reduction.

  9. Sustainable Application of Pecan Nutshell Waste: Greener Synthesis of Pd-based Nanocatalysts for Electro-oxidation of Methanol

    Science.gov (United States)

    Palladium-based electrocatalysts are widely used in alkaline direct alcohol fuel cells. Thesynthesis and characterization of carbon-supported bimetallic nanoparticles (NP) of AuPdand AgPd is described using pecan nutshell extract (Carya illinoinensis) which serves asboth, reducin...

  10. Characterization of G6PD genotypes and phenotypes on the northwestern Thailand-Myanmar border.

    Directory of Open Access Journals (Sweden)

    Germana Bancone

    Full Text Available Mutations in the glucose-6-phosphate dehydrogenase (G6PD gene result in red blood cells with increased susceptibility to oxidative damage. Significant haemolysis can be caused by primaquine and other 8-aminoquinoline antimalarials used for the radical treatment of Plasmodium vivax malaria. The distribution and phenotypes of mutations causing G6PD deficiency in the male population of migrants and refugees in a malaria endemic region on the Thailand-Myanmar border were characterized. Blood samples for G6PD fluorescent spot test (FST, G6PD genotyping, and malaria testing were taken from 504 unrelated males of Karen and Burman ethnicities presenting to the outpatient clinics. The overall frequency of G6PD deficiency by the FST was 13.7%. Among the deficient subjects, almost 90% had the Mahidol variant (487G>A genotype. The remaining subjects had Chinese-4 (392G>T, Viangchan (871G>A, Açores (595A>G, Seattle (844G>C and Mediterranean (563C>T variants. Quantification of G6PD activity was performed using a modification of the standard spectrophotometric assay on a subset of 24 samples with Mahidol, Viangchan, Seattle and Chinese-4 mutations; all samples showed a residual enzymatic activity below 10% of normal and were diagnosed correctly by the FST. Further studies are needed to characterise the haemolytic risk of using 8-aminoquinolines in patients with these genotypes.

  11. Vibrational states on Pd surfaces

    Science.gov (United States)

    Sklyadneva, I. Yu.; Rusina, G. G.; Chulkov, E. V.

    1997-04-01

    We present the calculation of vibrational modes and lattice relaxation for the Pd(100), (110) and (111) surfaces. The surface phonon frequencies and polarizations are obtained using embedded-atom potentials. Comparison of the calculated frequency values with available experimental data gives agreement within 0.2 THz.

  12. Empowering Patients: PD in Healthcare

    DEFF Research Database (Denmark)

    Kensing, Finn; Strand, Dixi Louise; Bansler, Jørgen P.

    2004-01-01

    In this paper, we discuss PD issues and concerns in the context of a national initiative the purpose of which is to provide IT support for the communication and collaboration within a heterogeneous network of patients/citizens and health care professionals. We present the notion of patient empowe...

  13. Sodium citrate assisted facile synthesis of AuPd alloy networks for ethanol electrooxidation with high activity and durability

    Science.gov (United States)

    Zhai, Yanling; Zhu, Zhijun; Lu, Xiaolin; Zhou, H. Susan

    2016-10-01

    The direct ethanol fuel cell is an emerging energy conversion device for which palladium is considered as the one of the most effective components for anode catalyst, however, its widespread application has been still limited by the activity and durability of the anode catalyst. In this work, AuPd alloy networks (NWs) are synthesized using H2PdCl4 and HAuCl4 as precursors reduced by NaBH4 in the presence of sodium citrate (SC). The results reveal that SC plays significant role in network structure, resulting in the enhanced electrocatalytic activity of the catalyst. This self-supported AuPd NWs catalyst exhibits much higher electrochemical catalytic activity than commercial Pd/C catalyst toward ethanol electrooxidation in alkaline solution. Significantly, AuPd NWs catalyst shows extremely high durability at the beginning of the chronoamperometry test, and as high as 49% of the mass current density (1.41 A/mgPd) remains after 4000 s current-time test at -0.3 V (vs. Ag/AgCl) in N2-saturated KOH-ethanol solution. This strategy provides a facile method for the preparation of alloy networks with high electrochemical activity, and can be potentially expanded to a variety of electrochemical applications.

  14. Pd Coated BaTiO3 Powder for Internal Electrode Applications

    Directory of Open Access Journals (Sweden)

    R. C. Stephenson

    2002-01-01

    new low cost air fired electrode technology. This paper presents a new electrode technology incorporating a uniform, continually coated AgPd over engineered dielectric particles. The resulting powder greatly reduces the consumption of precious metal, and provides superior thermal mechanical properties. This is achieved by matching the core ceramic structure of the powder to the manufacturer's dielectric, thereby controlling shrinkage while maintaining desired electrical properties.

  15. PD-1 Expression in primary cutaneous lymphoma

    NARCIS (Netherlands)

    Cetinozman, F.

    2016-01-01

    The molecule programmed death-1 (PD-1) is a critical element in the negative regulation of cellular immune responses. Blockage of the interaction between PD-1 and its ligand PD-L1 has emerged as a promising therapeutic approach for several cancers underlining the importance of this molecule. Express

  16. The role of Ag precipitates in Cu-12 wt% Ag

    Energy Technology Data Exchange (ETDEWEB)

    Yao, D.W.; Song, L.N. [Department of Materials Science and Engineering, Zhejiang University, Zheda Road No.38, Hangzhou, Zhejiang 310027 (China); Dong, A.P.; Wang, L.T. [China Railway Construction Electrification Bureau Group Co.,Ltd., Beijing 100036 (China); Zhang, L. [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Meng, L., E-mail: mengliang@zju.edu.cn [Department of Materials Science and Engineering, Zhejiang University, Zheda Road No.38, Hangzhou, Zhejiang 310027 (China)

    2012-12-15

    The Cu-12 wt% Ag was prepared to investigate the role of Ag precipitates on the properties of the alloy. Two kinds of heat treatment procedures were adopted to produce different amount of Ag precipitates in the Cu-12 wt% Ag. The microstructure of Ag precipitates was systematically observed by optical microscopy and electron microscopy. The Cu-12 wt% Ag with more Ag precipitates exhibits higher strength and lower electrical conductivity. More Ag precipitates results in more phase interface and less Ag atoms dissolved in Cu matrix. By comparing the strengthening effect and electron scattering effect of phase interface and dissolved Ag atoms, it is conclude that the interface between Cu matrix and Ag precipitates could significantly block dislocation movement and enhance electron scattering in Cu-Ag alloys.

  17. Identification of antigens by monoclonal antibody PD4 and its expression in Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    Jin-Ying Ning; Guo-Xun Sun; Su Huang; Hong Ma; Ping An; Lin Meng; Shu-Mei Song; Jian Wu; Cheng-Chao Shou

    2003-01-01

    AIM: To clone and express the antigen of monoclonal antibody (Mab) PD4 for further investigation of its function.METHODS: MGC803 cDNA expression library was constructed and screened with PD4 as probes to clone the antigen. After failed in the library screening, immunoprecipitation and SDSpolyacrylamide gel electrophoresis were applied to purify the antigen for sequence analysis. The antigen coming from Nycoplasma hyorhinis (M. Hyorhinis) was further confirmed with Western blot analysis by infecting M. Hyorhinis-free HeLa cells and eliminating the M. Hyorhinis from MGC803cells. The full p37 gene was cloned by PCR and expressed successfully in Escherichia coli after site-directed mutations.Tmmunofluorescence assay was used to demonstrate if p37protein could directly bind to gastric tumor cell AGS.RESULTS: The cDNA library constructed with MGC803 cells was screened by Mab PD4 as probes. Unfortunately, the positive clones identified with Mab PD4 were also reacted with unrelated antibodies. Then, immunoprecipitation was performed and the purified antigen was identified to be a membrane protein of Mycoplasrna hyorhinis (M. Hyorhinis)by sequencing of N-terminal amino acid residues. The membrane protein was intensively verified with Western blot by eliminating M. Hyorhinis from MGC803 cells and by infecting M. Hyorhinis-free HeLa cells. The full p37 gene was cloned and expressed successfully in Escherichia coli after site-directed mutations. Immunofluorescence demonstrated that p37protein could directly bind to gastric tumor cell AGS.CONCLUSION: The antigen recognized by Mab PD4 is from M. Hyorhinis, which suggests the actions involved in Mab PD4 is possibly mediated by p37 protein or M. Hyorhinis. As p37 protein can bind directly to tumor cells, the pathogenic role of p37 involved in tumorigenesis justifies further investigation.

  18. PD-1/PD-L1 expression in chromophobe renal cell carcinoma: An immunological exception?

    Science.gov (United States)

    Erlmeier, Franziska; Hartmann, Arndt; Autenrieth, Michael; Wiedemann, Max; Ivanyi, Philipp; Steffens, Sandra; Weichert, Wilko

    2016-11-01

    Immune checkpoint inhibitors targeting the inhibitory cross talk between tumor and immune cells have been approved for therapy in renal cell carcinoma (RCC). In contrast to clear cell RCC, little is known on PD-1/PD-L1 expression patterns in rarer RCC subtypes. The aim of this study was to evaluate the prevalence, distribution and prognostic impact of PD-1 and PD-L1 expression in chromophobe (ch)RCC. Patients who underwent renal surgery due to chRCC were retrospectively evaluated. Tumor specimen was analyzed for PD-1 and PD-L1 expression by immunohistochemistry. Expression data were correlated with clinic-pathological parameters including patient survival. Eighty-one chRCC patients were eligible for analysis, thereof 25 (30.9 %) and 11 (13.6 %) patients were positive for PD-1(+) tumor-infiltrating mononuclear cells (TIMCs) and tumoral PD-L1(+) expression, respectively. No significant associations were found for PD-1(+) TIMC or tumoral PD-L1(+) expression and clinical attributes. In addition, no differences in 5- and 10-year overall survival for PD-1(-) TIMC compared to PD-1(+) TIMC (90.5 and 72.2 vs. 100 and 75 %; p = 0.41) and for PD-L1(-) tumors compared to PD-L1(+) tumors (91.9 and 76.4 vs. 100 and 50 %; p = 0.48) were observed. In conclusion, to our knowledge this is the first study to evaluate the prognostic impact of PD-1 and PD-L1 in chRCC. PD-L1 does seem to be expressed in a minority of all chRCC, likewise only a minority of chRCC was infiltrated by PD-1-positive inflammatory cells. Neither PD-1(+) TIMC nor tumoral PD-L1(+) expression was associated with parameters of aggressiveness or survival.

  19. Preparation of (103)Pd brachytherapy seeds by electroless plating of (103)Pd onto carbon bars.

    Science.gov (United States)

    Li, Zhong-Yong; Gao, Hui-Bo; Deng, Xue-Song; Zhou, Leng; Zhang, Wen-Hui; Han, Lian-Ge; Jin, Xiao-Hai; Cui, Hai-Ping

    2015-09-01

    A method for preparing (103)Pd brachytherapy seeds is reported. The key of the method was to deposit (103)Pd onto carbon bars by electroless plating so as to prepare source cores. After each carbon bar with (103)Pd was sealed in a titanium capsule, the (103)Pd seeds were fabricated. This paper provides valuable experiences and data for the preparation of (103)Pd brachytherapy seeds.

  20. Magnetic behavior of Pd nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    Aguilera-Granja, F. [Instituto de Fisica ' Manuel Sandoval Vallarta' , Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, 78000 San Luis Potosi, S.L.P. (Mexico)]. E-mail: faustino@dec1.ifisica.uaslp.mx; Montejano-Carrizales, J.M. [Instituto de Fisica ' Manuel Sandoval Vallarta' , Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, 78000 San Luis Potosi, S.L.P. (Mexico); Berlanga-Ramirez, E.O. [Instituto de Fisica ' Manuel Sandoval Vallarta' , Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, 78000 San Luis Potosi, S.L.P. (Mexico); Vega, A. [Departamento de Fisica Teorica, Atomica, Nuclear y Optica, Universidad de Valladolid, E-47011 Valladolid (Spain)

    2004-12-31

    We study the magnetic properties of free-standing Pd clusters of some selected sizes with icosahedral structures which are obtained as the most stable ones using the Embedded Atom Method from an uniform relaxation of different geometrical configurations. The spin-polarized electronic structure and related magnetic properties of those optimized geometries were calculated by solving self-consistently a spd tight-binding Hamiltonian. The magnetic moments obtained in our calculations present a step-like dependence as a function of the exchange parameter in the case of small cluster sizes and a more complex dependence for larger cluster sizes is found. We discuss the results in comparison with previous calculations for FCC Pd clusters and with recent experimental findings. We also study the dependence of the magnetic moments distribution within the clusters with some geometrical effects such as hydrostatic deformations and twining.

  1. AGS experiments: 1993 - 1994 - 1995

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1996-04-01

    This report contains: FY 1995 AGS Schedule as Run; FY 1996-97 AGE Schedule (working copy); AGS Beams 1995; AGS Experimental Area FY 1993 Physics Program; AGS Experimental Area FY 1994 Physics Program; AGS Experimental Area FY 1995 Physics Program; AGS Experimental Area FY 1996 Physics Program (In progress); A listing of experiments by number; Two-page summaries of each experiment begin here, also ordered by number; Listing of publications of AGS experiments begins here; and Listing of AGS experimenters begins here. This is the twelfth edition.

  2. Acoustic Analysis of PD Speech

    Directory of Open Access Journals (Sweden)

    Karen Chenausky

    2011-01-01

    Full Text Available According to the U.S. National Institutes of Health, approximately 500,000 Americans have Parkinson's disease (PD, with roughly another 50,000 receiving new diagnoses each year. 70%–90% of these people also have the hypokinetic dysarthria associated with PD. Deep brain stimulation (DBS substantially relieves motor symptoms in advanced-stage patients for whom medication produces disabling dyskinesias. This study investigated speech changes as a result of DBS settings chosen to maximize motor performance. The speech of 10 PD patients and 12 normal controls was analyzed for syllable rate and variability, syllable length patterning, vowel fraction, voice-onset time variability, and spirantization. These were normalized by the controls' standard deviation to represent distance from normal and combined into a composite measure. Results show that DBS settings relieving motor symptoms can improve speech, making it up to three standard deviations closer to normal. However, the clinically motivated settings evaluated here show greater capacity to impair, rather than improve, speech. A feedback device developed from these findings could be useful to clinicians adjusting DBS parameters, as a means for ensuring they do not unwittingly choose DBS settings which impair patients' communication.

  3. Shape-controlled synthesis of Pt-Pd core-shell nanoparticles exhibiting polyhedral morphologies by modified polyol method

    Energy Technology Data Exchange (ETDEWEB)

    Long, Nguyen Viet, E-mail: nguyenviet_long@yahoo.com [Department of Materials Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Posts and Telecommunications Institute of Technology, Nguyen Trai, Hanoi (Viet Nam); Asaka, Toru; Matsubara, Takashi [Department of Materials Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Nogami, Masayuki, E-mail: nogami@nitech.ac.jp [Department of Materials Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan)

    2011-04-15

    Pt-Pd core-shell nanoparticles were synthesized by a simple synthetic method. First, Pt nanoparticles were synthesized in a controlled manner via the reduction of chloroplantinic acid hexahydrate in ethylene glycol (EG) at 160 deg. C in the presence of silver nitrate and the stabilization of polyvinylpyrrolidon. AgNO{sub 3} used acts as a structure-modifying agent to the morphology of the Pt nanoparticles. These Pt nanoparticles function as the seeds for the successive reduction of sodium tetrachloropalladate (II) hydrate in EG under stirring for 15 min at 160 deg. C in order to synthesize Pt-Pd core-shell nanoparticles. To characterize the as-prepared Pt-Pd nanoparticles, transmission electron microscopy (TEM) and high-resolution TEM are used. The high-resolution elemental mappings were carried out using the combination of scanning TEM and X-ray energy-dispersive spectroscopy. The results also demonstrate the homogeneous nucleation and growth of the Pd metal shell on the definite Pt core. The synthesized Pt-Pd core-shell nanoparticles exhibit a sharp and polyhedral morphology. The epitaxial growth of the controlled Pd shells on the Pt cores via a polyol method was observed. It is suggested that Frank-van der Merwe and Stranski-Krastanov growth modes coexisted in the nucleation and growth of Pt-Pd core-shell nanoparticles.

  4. Beta decay of medium and high spin isomers in sup 9 sup 4 Ag

    CERN Document Server

    La Commara, M; Döring, J; Galanopoulos, S; Grawe, H; Harissopoulos, S V; Hellström, M; Janas, Z; Kirchner, R; Mazzocchi, C; Ostrowski, A N; Plettner, C; Rainovski, G; Roeckl, E; Schmidt, K

    2002-01-01

    The very neutron-deficient isotope sup 9 sup 4 Ag was produced at the GSI on-line mass separator by using the reaction sup 5 sup 8 Ni( sup 4 sup 0 Ca, p3n). The beta-decay properties of sup 9 sup 4 Ag were studied by detecting for the first time beta-delayed gamma rays and beta-gamma-gamma coincidences. Both the population of excited levels in the daughter nucleus sup 9 sup 4 Pd and the beta-decay half-life of sup 9 sup 4 Ag were investigated. The major part of the feeding was assigned to the decay of an I suppi=(7 sup +) isomer with a half-life of (0.36+-0.03) s. A weak beta-decay branch was found to populate high-spin levels in the sup 9 sup 4 Pd daughter with I>=18. It is tentatively assigned to the decay of a high-spin parent state in sup 9 sup 4 Ag with I>=17 and a half-life (0.3+-0.2) s. The measured beta-decay properties as well as the level structure of sup 9 sup 4 Ag and sup 9 sup 4 Pd are discussed in comparison with shell-model predictions.

  5. PD-1/PD-Ls pathways between CD4(+) T cells and pleural mesothelial cells in human tuberculous pleurisy.

    Science.gov (United States)

    Yin, Wen; Tong, Zhao-Hui; Cui, Ai; Zhang, Jian-Chu; Ye, Zhi-Jian; Yuan, Ming-Li; Zhou, Qiong; Shi, Huan-Zhong

    2014-03-01

    Programmed death 1 (PD-1), PD-ligand 1 (PD-L1), and PD-L2 have been demonstrated to be involved in tuberculosis immunity, however, the expression and regulation of PD-1/PD-Ls pathways in pleural mesothelial cells (PMCs) and CD4(+) T cells in tuberculous pleural effusion (TPE) have not been investigated. Expression of PD-1 on CD4(+) T cells and expressions of PD-L1 and PD-L2 on PMCs in TPE were determined. The impacts of PD-1/PD-Ls pathways on proliferation, apoptosis, adhesion, and migration of CD4(+) T cells were explored. Concentrations of soluble PD-l, but not of soluble PD-Ls, were much higher in TPE than in serum. Expressions of PD-1 on CD4(+) T cells in TPE were significantly higher than those in blood. Expressions of PD-Ls were much higher on PMCs from TPE when compared with those from transudative effusion. Interferon-γ not only upregulated the expression of PD-1 on CD4(+) T cells, but also upregulated the expressions of PD-Ls on PMCs. Blockage PD-1/PD-Ls pathways abolished the inhibitory effects on proliferation and adhesion activity of CD4(+) T cells induced by PMCs. PD-1/PD-Ls pathways on PMCs inhibited proliferation and adhesion activity of CD4(+) T cells, suggesting that Mycobacterium tuberculosis might exploit PD-1/PD-Ls pathways to evade host cell immune response in human.

  6. Design of a Multi-Tube Pd-Membrane Module for Tritium Recovery from He in DEMO

    Directory of Open Access Journals (Sweden)

    Marco Incelli

    2016-10-01

    Full Text Available Dense self-supported Pd-alloy membranes are used to selectively separate hydrogen and hydrogen isotopes. In particular, deuterium (D and tritium (T are currently identified as the main elements for the sustainability of the nuclear fusion reaction aimed at carbon free power generation. In the fusion nuclear reactors, a breeding blanket produces the tritium that is extracted and purified before being sent to the plasma chamber in order to sustain the fusion reaction. In this work, the application of Pd-alloy membranes has been tested for recovering tritium from a solid breeding blanket through a helium purge stream. Several simulations have been performed in order to optimize the design of a Pd-Ag multi-tube module in terms of geometry, operating parameters, and membrane module configuration (series vs. parallel. The results demonstrate that a pre-concentration stage before the Pd-membrane unit is mandatory because of the very low tritium concentration in the He which leaves the breeding blanket of the fusion reactor. The most suitable operating conditions could be reached by: (i increasing the hydrogen partial pressure in the lumen side and (ii decreasing the shell pressure. The preliminary design of a membrane unit has been carried out for the case of the DEMO fusion reactor: the optimized membrane module consists of an array of 182 Pd-Ag tubes of 500 mm length, 10 mm diameter, and 0.100 mm wall thickness (total active area of 2.85 m2.

  7. Research of 103Pd Seed Source Preparation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Having very good nuclide properties, 103Pd is an important radioisotope for the use of cancer local treatment (brachytherapy).Using the high puried 103Pd solution, by the way of electroplating, the 103Pd is deposited on the surface of metal bar, then the metal bar coated with 103Pd is sealed in titanium tube. For a seed, the dimensions are φ0.8 mm× 4.5 mm and the typical activity of individual 103Pd seed varies from 18.5-37 MBq. 103Pd seeds by batches can be offered at present and the product is checked out by SDA. Clinical trials have finished in Beijing and Guangzhou,

  8. Excited states of neutron rich Pd from fragmentation

    Science.gov (United States)

    Hecht, A. A.; Walters, W. B.; Hoteling, N.; Mantica, P. F.; Becerril, A.; Fleckenstein, T.; Lorusso, G.; Pereira, J.; Pinter, J.; Stoker, J.; Quinn, M.

    2007-04-01

    The neutron rich region approaching N=82 and Z=50 is interesting for nuclear structure and nuclear astrophysics, both as a test of the shell closures far from stability and as the path for r-process nucleosynthesis. This region is difficult to access with fusion-evaporation reactions and novel techniques must be used. At the National Superconducting Cyclotron Laboratory (NSCL) an experiment was recently performed by fragmentation of a Xe beam using a Be target to examine isomers and beta decay from these neutron rich nuclei. The radioisotope fragments passed through several Si planar detectors and were implanted in a double-sided Si strip detector (DSSD) in the Beta Counting System (BCS). Fragments were identified via δE and TOF. Particle emitting decays were tracked in several layers of single sided strip detectors following the DSSD, while the SEGA array surrounding the DSSD was used to collect gamma emission following beta and isomer decay. Several neutron rich nuclei were observed in this experiment, including Ru, Rh, Pd, Ag, Cd, and In. Results on Pd will be discussed.

  9. Comparative corrosion study of Ag–Pd and Co–Cr alloys used in dental applications

    Indian Academy of Sciences (India)

    D Mareci; D Sutiman; A Cailean; G Bolat

    2010-08-01

    The electrochemical behaviour of two Ag–Pd alloys (Unique White and Paliag) used in dental prosthetics construction for crowns and bridges and one Co–Cr alloy (Vitallium 2000) was studied in artificial saliva using the polarization curves and electrochemical impedance spectroscopy (EIS). The corrosion resistance was evaluated by means of the corrosion currents value and by coulometric analysis. The open circuit potential of Ag–Pd are attributed to dealloying followed by surface enrichment with Ag and the possible formation of an insoluble AgCl surface film on the respective alloy surfaces. Our results have shown that these alloys have a somewhat good corrosion resistance in artificial saliva. The corrosion current densities of Unique White and Vitallium 2000 alloys were very low (∼100 nA/cm2). For Ag–Pd alloys, when increasing the content of Cu, corrosion resistance decreases. The passivation of all samples occurred spontaneously at the open circuit potential. The electrochemical properties of the spontaneously passivated electrodes at the open circuit potential were studied by EIS. The polarization resistance (p) and the electrode capacitance (dl) were determined. The polarization resistance of all the samples increases with the immersion time. The polarization resistances are largest for Unique White (Ag–Pd) and Vitallium 2000 (Co–Cr) alloys. Because the electrochemical behaviour of the Co–Cr alloy was compared with that of Ag–Pd alloy, this type of alloy may be a suitable alternative for use in the manufacture of fixed dental prostheses. The present study, though limited, has shown that electrochemical characteristics can be used to identify such alloys. Knowledge of the in vitro corrosion behaviour of these alloys may lead to better understanding of any biologically adverse effects in vitro.

  10. Salmonella impairs CD8 T cell response through PD-1: PD-L axis.

    Science.gov (United States)

    López-Medina, Marcela; Carrillo-Martín, Ismael; Leyva-Rangel, Jessica; Alpuche-Aranda, Celia; Ortiz-Navarrete, Vianney

    2015-12-01

    We have shown that Salmonella remains for a long period of time within B cells, plasma cells, and bone marrow B cell precursors, which might allow persistence and dissemination of infection. Nonetheless, how infected cells evade CD8 T cell response has not been characterized. Evidence indicates that some pathogens exploit the PD-1: PD-L (PD-L1 and PD-L2) interaction to inhibit CD8 T cells response to contribute the chronicity of the infection. To determine whether the PD-1: PD-L axis plays a role during Salmonella infection; we evaluated PD-1 expression in antigen-specific CD8 T cells and PD-1 ligands in Salmonella-infected cells. Our results show that infected B cells and macrophages express continuously co-stimulatory (CD40, CD80, and CD86) and inhibitory molecules (PD-L1 and PD-L2) in early and late stages of chronic Salmonella infection, while antigen-specific CD8 T cells express in a sustained manner PD-1 in the late stages of infection. Blocking this axis restores the ability of the CD8 T cells to proliferate and eliminate primary infected APCs. Therefore, a continuous PD-1: PDL interaction might be a mechanism employed by Salmonella to negatively regulate Salmonella-specific CD8 T cell cytotoxic response in order to remain within the host for a long period of time.

  11. Immune targeting of PD-1{sup hi} expressing cells during and after antiretroviral therapy in SIV-infected rhesus macaques

    Energy Technology Data Exchange (ETDEWEB)

    Vargas-Inchaustegui, Diego A.; Xiao, Peng; Hogg, Alison E.; Demberg, Thorsten; McKinnon, Katherine [Vaccine Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States); Venzon, David [Biostatistics and Data Management Section, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States); Brocca-Cofano, Egidio; DiPasquale, Janet [Vaccine Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States); Lee, Eun M.; Hudacik, Lauren; Pal, Ranajit [Advanced Bioscience Laboratories Inc., Rockville, MD 20850 (United States); Sui, Yongjun; Berzofsky, Jay A. [Vaccine Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States); Liu, Linda; Langermann, Solomon [Amplimmune Inc., Gaithersburg, MD 20878 (United States); Robert-Guroff, Marjorie, E-mail: guroffm@mail.nih.gov [Vaccine Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States)

    2013-12-15

    High-level T cell expression of PD-1 during SIV infection is correlated with impaired proliferation and function. We evaluated the phenotype and distribution of T cells and Tregs during antiretroviral therapy plus PD-1 modulation (using a B7-DC-Ig fusion protein) and post-ART. Chronically SIV-infected rhesus macaques received: 11 weeks of ART (Group A); 11 weeks of ART plus B7-DC-Ig (Group B); 11 weeks of ART plus B7-DC-Ig, then 12 weeks of B7-DC-Ig alone (Group C). Continuous B7-DC-Ig treatment (Group C) decreased rebound viremia post-ART compared to pre-ART levels, associated with decreased PD-1{sup hi} expressing T cells and Tregs in PBMCs, and PD-1{sup hi} Tregs in lymph nodes. It transiently decreased expression of Ki67 and α{sub 4}β{sub 7} in PBMC CD4{sup +} and CD8{sup +} Tregs for up to 8 weeks post-ART and maintained Ag-specific T-cell responses at low levels. Continued immune modulation targeting PD-1{sup hi} cells during and post-ART helps maintain lower viremia, keeps a favorable T cell/Treg repertoire and modulates antigen-specific responses. - Highlights: • B7-DC-Ig modulates PD-1{sup hi} cells in SIV-infected rhesus macaques during and post-ART. • Continued PD-1 modulation post-ART maintains PD-1{sup hi} cells at low levels. • Continued PD-1 modulation post-ART maintains a favorable T cell and Treg repertoire.

  12. Plasmonic effect-enhanced Ag nanodisk incorporated ZnO/Si metal-semiconductor-metal photodetectors

    Science.gov (United States)

    Kumar, Manjeet; Kojori, Hossein Shokri; Kim, Sung Jin; Park, Hyeong-Ho; Kim, Joondong; Yun, Ju-Hyung

    2016-10-01

    In this work, we present the enhancement of ultraviolet (UV) photodetection of Ag-ZnO thin film deposited by radio frequency magnetron sputtering. The surface morphological, optical, structural, and electrical properties of the deposited thin films were investigated by various characterization techniques. With this Ag-ZnO thin film structure and proper geometry of metal-semiconductor-metal (MSM) interdigitated structure design, photocurrent enhancement has been accomplished. MSM-photodetectors (PDs) using structures of Ag-ZnO gave a 30 times higher magnitude photocurrent at 340 nm of the wavelength. Plasmon-induced hot electrons contributed to improved spectral response to the UV region, while absorption and scattering effect enhanced broadband improvement to a response in the VIS-IR spectrum range. The improvement of Ag-ZnO PD in comparison with ZnO is attributed to the surface plasmon effect using Ag nanodisks. These results indicate that Ag-ZnO thin films can serve as excellent ultraviolet-PD and a very promising candidate for practical applications.

  13. Methane Oxidation on Pd-Ceria. A DFT Study of the Combustion Mechanism over Pd, PdO and Pd-ceria Sites

    Energy Technology Data Exchange (ETDEWEB)

    Mayernick, Adam D. [Pennsylvania State Univ., State College, PA (United States); Janik, Michael J. [Pennsylvania State Univ., State College, PA (United States)

    2010-12-24

    Palladium/ceria exhibits unique catalytic activity for hydrocarbon oxidation; however, the chemical and structural properties of active sites on the palladium–ceria surface are difficult to characterize. Strong interactions between palladium and the ceria support stabilize oxidized Pdδ+ species, which may contribute to the significant activity of Pd/ceria for methane oxidation. We present a density functional theory (DFT + U) investigation into methane oxidation over Pd/ceria and quantify the activity of the PdxCe1-xO2(1 1 1) mixed oxide surface in comparison with the PdO(1 0 0) and Pd(1 1 1) surfaces. The methane activation barrier is lowest over the PdxCe1-xO2(1 1 1) surface, even lower than over the Pd(1 1 1) surface or low coordinated stepped or kinked Pd sites. Subsequent reaction steps in complete oxidation, including product desorption and vacancy refilling, are considered to substantiate that methane activation remains the rate-limiting step despite the low barrier over PdxCe1-xO2(1 1 1). The low barrier over the PdxCe1-xO2(1 1 1) surface demonstrates that mixed ceria-noble metal oxides offer the potential for improved hydrocarbon oxidation performance with respect to dispersed noble metal particles on ceria.

  14. Pt-Pd bimetallic nanoparticles on MWCNTs: catalyst for hydrogen peroxide electrosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Felix-Navarro, R. M., E-mail: moi6salazar@hotmail.com; Beltran-Gastelum, M.; Salazar-Gastelum, M. I.; Silva-Carrillo, C.; Reynoso-Soto, E. A.; Perez-Sicairos, S.; Lin, S. W. [Centro de Graduados e Investigacion, Instituto Tecnologico de Tijuana (Mexico); Paraguay-Delgado, F. [Centro de Investigacion en Materiales Avanzados (Mexico); Alonso-Nunez, G. [Centro de Nanociencias y Nanotecnologia (Mexico)

    2013-08-15

    Bimetallic nanoparticles of Pt-Pd were deposited by the microemulsion method on a multiwall carbon nanotube (MWCNTs) to obtain a Pt-Pd/MWCNTs for electrocatalytic reduction of O{sub 2} to H{sub 2}O{sub 2}. The activity and selectivity of the catalyst was determined qualitatively by the rotating disk electrode method in acidic medium. The catalyst was spray-coated onto a reticulated vitreous carbon substrate and quantitatively was tested in bulk electrolysis for 20 min under potentiostatic conditions (0.5 V vs Ag/AgCl) in a 0.5 M H{sub 2}SO{sub 4} electrolyte using dissolved O{sub 2}. The bulk electrolysis experiments show that the Pt-Pd/MWCNTs catalyst is more efficient for H{sub 2}O{sub 2} electrogeneration than a MWCNTs catalyst. Nitrobenzene degradation by electrogenerated H{sub 2}O{sub 2} alone and Electro-Fenton process were also tested. Our results show that both processes decompose nitrobenzene, but the Electro-Fenton process does it more efficiently. The prepared nanoparticulated catalyst shows a great potential in environmental applications.

  15. Dinuclear PCP pincer complexes from Lewis acidic [Pd(OTf)(PCP)] and basic [Pd(4-Spy)(PCP)] (OTf = triflate; 4-Spy = 4-pyridinethiolate; PCP = (-)CH(CH(2)CH(2)PPh(2))(2)).

    Science.gov (United States)

    Neo, Kian Eang; Huynh, Han Vinh; Koh, Lip Lin; Henderson, William; Hor, T S Andy

    2007-12-28

    The Lewis acidic pincer with a labile triflate ligand, viz. [Pd(OTf)(PCP)] (PCP = (-)CH(CH(2)CH(2)PPh(2))(2)) was prepared from [PdCl(PCP)] with AgOTf. It reacts readily with neutral bidentate ligands [L = 4,4'-bipyridine (4,4'-bpy) and 1,1'-bis(diphenylphosphino)ferrocene (dppf)] to give dinuclear PCP pincers [{Pd(PCP)}(2)(micro-L)][OTf](2) (L = 4,4'-bpy, 2; dppf,3). [PdCl(PCP)] also reacts with 4-mercaptopyridine in the presence of KOH to give a Lewis basic pincer with a free pyridine functional group [Pd(4-Spy)(PCP)]4. Its metalloligand character is exemplified by the isolation of an asymmetric dinuclear double-pincer complex [{Pd(PCP)}(2)(micro-4-Spy)][PF(6)] 6 bridged by an ambidentate pyridinethiolato ligand. Complexes 1, 2, 3, 4 and 6 have been characterized by single-crystal X-ray diffraction analyses.

  16. Preparation and Nonlinearity properties of Pd Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Pd nanoparticles less than 8 nm were photoinduced by a near-IR femtosecond laser. The sign of the refraction nonlinearity is negative for the Pd nanoparticles with TiO2, while it is positive for those without TiO2.

  17. PD-L1-specific T cells

    DEFF Research Database (Denmark)

    Ahmad, Shamaila Munir; Borch, Troels Holz; Hansen, Morten

    2016-01-01

    for targeting the tumor microenvironment and for boosting the clinical effects of additional anticancer immunotherapy. This review summarizes present information about PD-L1 as a T cell antigen, depicts the initial findings about the function of PD-L1-specific T cells in the adjustment of immune responses...

  18. CO oxidation on PdO surfaces

    DEFF Research Database (Denmark)

    Hirvi, Janne T.; Kinnunen, Toni-Jani J.; Suvanto, Mika;

    2010-01-01

    , the reaction with the site blocking molecular oxygen is slightly more favorable, enabling also possible formation of carbonate surface species at low temperatures. The extreme activity of strongly bonded surface oxygen atoms is more greatly emphasized on the PdO(100)–O surface. The direct reaction without...... adsorption, following the Eley–Rideal mechanism and taking advantage of the reaction tunnel provided by the adjacent palladium atom, has an activation energy of only 0.24 eV. The reaction mechanism and activation energy for the palladium activated CO oxidation on the most stable PdO(100)–O surface......Density functional calculations were performed in order to investigate CO oxidation on two of the most stable bulk PdO surfaces. The most stable PdO(100) surface, with oxygen excess, is inert against CO adsorption, whereas strong adsorption on the stoichiometric PdO(101) surface leads to favorable...

  19. Synthesis of novel AuPd nanoparticles decorated one-dimensional ZnO nanorod arrays with enhanced photoelectrochemical water splitting activity.

    Science.gov (United States)

    Lu, Yan; Zhang, Junlong; Ge, Lei; Han, Changcun; Qiu, Ping; Fang, Siman

    2016-12-01

    The vertically aligned one-dimensional (1D) ZnO nanorod arrays decorated with AuPd alloy nanoparticles have been synthesized with ZnO nanorod arrays as template via a mild hydrothermal method. In this work, the as-prepared AuPd/ZnO nanorod arrays demonstrated high light-harvesting efficiency. The microstructures, morphologies and chemical properties of the obtained AuPd/ZnO composite photocatalyst were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectra (DRS) and X-ray photoelectron spectroscopy (XPS). The photoelectrochemical (PEC) performances of as-obtained AuPd/ZnO nanorod arrays were examined, and the photocurrent density was up to 0.98mAcm(-2) at 0.787V versus Ag/AgCl, which was about 2.4 times higher than the pure ZnO sample. A possible photocatalytic mechanism of the AuPd/ZnO hybrid nanostructures under the simulated sunlight irradiation was proposed to guide further improvement of other desirable materials. According to the above experiment results, it can be clearly found that AuPd/ZnO composite nanorod arrays showed excellent PEC performance and had promising applications in the utilization of solar energy.

  20. Nonenzymatic glucose sensor based on flower-shaped Au-Pd core-shell nanoparticles-ionic liquids composite film modified glassy carbon electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xianlan [Fujian Key Lab of Medical Instrument and Pharmaceutical Technology, Yishan Campus, Fuzhou University, Fuzhou, Fujian 350002 (China); Institute of Research for Functional Materials, Fuzhou University, Yishan Campus, Fuzhou University, Fuzhou, Fujian 350108 (China); College of Chemistry and Chemical Engineering, Qishan Campus, Fuzhou University, Fuzhou, Fujian 350108 (China); Pan Hiabo, E-mail: hbpan@fzu.edu.c [Fujian Key Lab of Medical Instrument and Pharmaceutical Technology, Yishan Campus, Fuzhou University, Fuzhou, Fujian 350002 (China); State Key Laboratory Breeding Base of Photocatalysis, Yishan Campus, Fuzhou University, Fuzhou, Fujian 350002 (China); Institute of Research for Functional Materials, Fuzhou University, Yishan Campus, Fuzhou University, Fuzhou, Fujian 350108 (China); College of Chemistry and Chemical Engineering, Qishan Campus, Fuzhou University, Fuzhou, Fujian 350108 (China); Liu Hongfang [Fujian Key Lab of Medical Instrument and Pharmaceutical Technology, Yishan Campus, Fuzhou University, Fuzhou, Fujian 350002 (China); College of Chemistry and Chemical Engineering, Qishan Campus, Fuzhou University, Fuzhou, Fujian 350108 (China); Du Min [Fujian Key Lab of Medical Instrument and Pharmaceutical Technology, Yishan Campus, Fuzhou University, Fuzhou, Fujian 350002 (China)

    2010-12-30

    A novel nonenzymatic glucose sensor based on flower-shaped (FS) Au -Pd core-shell nanoparticles-ionic liquids (ILs i.e., trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl) imide, [P(C{sub 6}){sub 3}C{sub 14}][Tf{sub 2}N]) composite film modified glassy carbon electrodes (GCE) was reported. The Au-Pd nanocatalysts were prepared by seed-mediated growth method, forming the three-dimensional FS nanoparticles, where tens of small Pd nanoparticles ({approx}3 nm) aggregated on gold seeds ({approx}20 nm). The FS Au-Pd nanoparticle was a good candidate for the catalytic efficiency of nanometallic surfaces because of its flower-shaped nature, which has greater adsorption capacity. XPS analysis and zeta potential indicated that the surface of Pd atoms is positively charged, profiting the oxidation process of glucose. And ILs acted as bridge connecting Au-Pd one another and bucky gel as platform within the whole nanocomposite. So the modified electrode has higher sensitivity and selectivity owing to intrinsic synergistic effects of this nanocomposite. Amperometric measurements allow observation of the electrochemical oxidation of glucose at 0.0 V (vs. Ag/AgCl), the glucose oxidation current is linear to its concentration in the range of 5 nM-0.5 {mu}M, and the detection limit was found to be 1.0 nM (S/N = 3). The as-prepared nonenzyme glucose sensor exhibited excellent stability, repeatability, and selectivity.

  1. Heterostructured Ag3PO4/AgBr/Ag plasmonic photocatalyst with enhanced photocatalytic activity and stability under visible light

    Science.gov (United States)

    Wang, Wan-Sheng; Du, Hong; Wang, Rui-Xia; Wen, Tao; Xu, An-Wu

    2013-03-01

    A heterostructured Ag3PO4/AgBr/Ag plasmonic photocatalyst was prepared by a rational in situ ion exchange reaction between Ag3PO4 micro-cubes and Br- in aqueous solution followed by photoreduction. The photocatalytic activities of obtained photocatalysts were measured by the degradation of methyl orange (MO) and methylene blue (MB) under visible light irradiation (λ >= 400 nm). Compared to AgBr/Ag, Ag3PO4/AgBr heterocrystals and pure Ag3PO4 crystals, the heterostructured Ag3PO4/AgBr/Ag plasmonic photocatalysts exhibit much higher photocatalytic activity and stability. This enhanced photocatalytic activity suggests that the synergetic effects of the heterostructured Ag3PO4/AgBr/Ag and the strong SPR of Ag NPs on the surface result in the high efficiencies of the photocatalytic activity and the improved stability. With the assistance of Ag3PO4/AgBr/Ag heterostructures, only 8 min and 12 min are taken to completely decompose MO and MB molecules under visible-light irradiation, respectively. Furthermore, the photodegradation rate does not show an obvious decrease during ten successive cycles, indicating that our heterostructured Ag3PO4/AgBr/Ag plasmonic photocatalysts are extremely stable under visible-light irradiation.A heterostructured Ag3PO4/AgBr/Ag plasmonic photocatalyst was prepared by a rational in situ ion exchange reaction between Ag3PO4 micro-cubes and Br- in aqueous solution followed by photoreduction. The photocatalytic activities of obtained photocatalysts were measured by the degradation of methyl orange (MO) and methylene blue (MB) under visible light irradiation (λ >= 400 nm). Compared to AgBr/Ag, Ag3PO4/AgBr heterocrystals and pure Ag3PO4 crystals, the heterostructured Ag3PO4/AgBr/Ag plasmonic photocatalysts exhibit much higher photocatalytic activity and stability. This enhanced photocatalytic activity suggests that the synergetic effects of the heterostructured Ag3PO4/AgBr/Ag and the strong SPR of Ag NPs on the surface result in the high

  2. Association between PD-1/PD-L1 and T regulate cells in early recurrent miscarriage.

    Science.gov (United States)

    Li, Guiyu; Lu, Caixia; Gao, Jing; Wang, Xietong; Wu, Huanling; Lee, Chao; Xing, Baoxiang; Zhang, Qi

    2015-01-01

    In this study, we try to testify the relationship between the programmed cell death receptor-1 (PD-1)/programmed cell death ligand 1 (PD-L1) passway and Treg cells in maternal-fetal immune regulation through PD-1 blockade on lymphocytes of normal early pregnancy in vitro and investigation of the PD-1 and PD-L1 changes in early recurrent miscarriage patients. CD4+ CD25+ Treg cells and PD-1 (CD279) positive cell were detected in deciduas in early recurrent miscarriage patients by flow cytometry. And the normal early pregnant women were as controls. Meanwhile the mRNA level of PD-1 and molecular expression of PD-L1 in deciduas of early recurrent miscarriage patients were detected by real time RT-PCR test and Immunohistochemical staining respectively. Also through antibody blocking assay to block PD-1 on lymphocytes of normal early pregnancy in vitro further testify the relationship between PD-1/PD-L1 and Treg cells, the results were analyzed by flow cytometry. CD4+ CD25+ Treg cells decreased both in deciduas in RM (P 0.05). PD-L1 mRNA in deciduas decreased in RM (P 0.1). After PD-1 blockade there was no change in CD4+ CD25+ Treg cells percentage, while the CD4+ T cell percentage increased (P < 0.01), as well as the level of IFN-gamma in cells supernatant (P < 0.01). PD-1 blockade has a little influence on the number of Treg cells, and may lead to impaired Treg cells function, the decrease of PD-L1 may closely relates to the occurrence of early recurrent miscarriage and implies that Treg cells may through PD-1/PD-L1 pathway play a role of immunosuppression regulation, and the impairment of Treg cells function in recurrent early abortion cases may be due to PD-L1 decrease in deciduas or trophoblast cells rather than PD-1 change.

  3. Hollow Au@Pd and Au@Pt core-shell nanoparticles as electrocatalysts for ethanol oxidation reactions

    KAUST Repository

    Song, Hyon Min

    2012-09-27

    Hybrid alloys among gold, palladium and platinum become a new category of catalysts primarily due to their enhanced catalytic effects. Enhancement means not only their effectiveness, but also their uniqueness as catalysts for the reactions that individual metals may not catalyze. Here, preparation of hollow Au@Pd and Au@Pt core-shell nanoparticles (NPs) and their use as electrocatalysts are reported. Galvanic displacement with Ag NPs is used to obtain hollow NPs, and higher reduction potential of Au compared to Ag, Pd, and Pt helps to produce hollow Au cores first, followed by Pd or Pt shell growth. Continuous and highly crystalline shell growth was observed in Au@Pd core-shell NPs, but the sporadic and porous-like structure was observed in Au@Pt core-shell NPs. Along with hollow core-shell NPs, hollow porous Pt and hollow Au NPs are also prepared from Ag seed NPs. Twin boundaries which are typically observed in large size (>20 nm) Au NPs were not observed in hollow Au NPs. This absence is believed to be due to the role of the hollows, which significantly reduce the strain energy of edges where the two lattice planes meet. In ethanol oxidation reactions in alkaline medium, hollow Au@Pd core-shell NPs show highest current density in forward scan. Hollow Au@Pt core-shell NPs maintain better catalytic activities than metallic Pt, which is thought to be due to the better crystallinity of Pt shells as well as the alloy effect of Au cores. © 2012 The Royal Society of Chemistry.

  4. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>AgEcon Search is a free,open access repository of full - text scholarly literature in agricultural and applied economics,inclu-ding working papers,conference papers,and journal articles. AgEcon Search is

  5. Investigating unexpected magnetism of mesoporous silica-supported Pd and PdO nanoparticles

    KAUST Repository

    Song, Hyon Min

    2015-01-13

    The synthesis and magnetic behavior of matrix-supported Pd and PdO nanoparticles (NPs) are described. Mesoporous silica with hexagonal columnal packing is selected as a template, and the impregnation method with thermal annealing is used to obtain supported Pd and PdO NPs. The heating rate and the annealing conditions determine the particle size and the phase of the NPs, with a fast heating rate of 30 °C/min producing the largest supported Pd NPs. Unusual magnetic behaviors are observed. (1) Contrary to the general belief that smaller Pd NPs or cluster size particles have higher magnetization, matrix-supported Pd NPs in this study maintain the highest magnetization with room temperature ferromagnetism when the size is the largest. (2) Twin boundaries along with stacking faults are more pronounced in these large Pd NPs and are believed to be the reason for this high magnetization. Similarly, supported PdO NPs were prepared under air conditions with different heating rates. Their phase is tetragonal (P42/mmc) with cell parameters of a = 3.050 Å and c = 5.344 Å, which are slightly larger than in the bulk phase (a = 3.03 Å, c = 5.33 Å). Faster heating rate of 30 °C/min also produces larger particles and larger magnetic hysteresis loop, although magnetization is smaller and few twin boundaries are observed compared to the supported metallic Pd NPs.

  6. User gains and PD aims

    DEFF Research Database (Denmark)

    Bossen, Claus; Dindler, Christian; Iversen, Ole Sejer

    2010-01-01

    We present a study of user gains from their participation in a participatory design (PD) project at Danish primary schools. We explore user experiences and reported gains from the project in relation to the multiple aims of PD, based on a series of interviews with pupils, teachers, administrators...... relationships among people, stretching across organizations and project groups. Moreover, we demonstrate how users' gains related to their acting within these networks. These results suggest a heightened focus on the indirect and distributed channels through which the long-term impact of PD emerges....

  7. High Spin Structure in 106Pd

    Institute of Scientific and Technical Information of China (English)

    于蓓蓓; 竺礼华; 贺创业; 吴晓光; 郑云; 李广生; 王烈林; 姚顺和; 张彪; 徐川; 郝昕; 王建国; 顾龙; 张明

    2012-01-01

    The high spin states of 106pd have been populated through the 100Mo(11B, lp4n)106Pd reaction using a beam energy of 60 MeV provided by the Beijing HI-13 tandem accel- erator at China Institute of Atomic Energy. By analyzing the V-3' coincidence relation and DCO raios of transitions, 3 rotational bands with 13 new states and 22 new 7 transitions belonging to 106pd were constructed. Bands 2 and 3 with negative parity were supposed to build on the vh1l/297/2 and vh11/2ds/2 configuration, respectively.

  8. Alternative splice variants of the human PD-1 gene

    DEFF Research Database (Denmark)

    Nielsen, Christian; Ohm-Laursen, Line; Barington, Torben;

    2005-01-01

    PD-1 is an immunoregulatory receptor expressed on the surface of activated T cells, B cells, and monocytes. We describe four alternatively spliced PD-1 mRNA transcripts (PD-1Deltaex2, PD-1Deltaex3, PD-1Deltaex2,3, and PD-1Deltaex2,3,4) in addition to the full length isoform. PD-1Deltaex2 and PD-1......Deltaex3 are generated by alternative splicing where exon 2 (extracellular IgV-like domain) and exon 3 (transmembrane domain) respectively are spliced out. PD-1Deltaex3 is therefore likely to encode a soluble form of PD-1. PD-1Deltaex2,3 lacks exon 2 and 3. These three variants have unaffected open...

  9. AGS Booster prototype magnets

    Energy Technology Data Exchange (ETDEWEB)

    Danby, G.; Jackson, J.; Lee, Y.Y.; Phillips, R.; Brodowski, J.; Jablonski, E.; Keohane, G.; McDowell, B.; Rodger, E.

    1987-03-19

    Prototype magnets have been designed and constructed for two half cells of the AGS Booster. The lattice requires 2.4m long dipoles, each curved by 10/sup 0/. The multi-use Booster injector requires several very different standard magnet cycles, capable of instantaneous interchange using computer control from dc up to 10 Hz.

  10. Anomalous Hall effect and magnetoresistance behavior in Co/Pd1−xAgx multilayers

    KAUST Repository

    Guo, Z. B.

    2013-02-13

    In this paper, we report anomalous Hall effect (AHE) correlated with the magnetoresistance behavior in [Co/Pd1-xAg x]n multilayers. For the multilayers with n = 6, the increase in Ag content from x = 0 to 0.52 induces the change in AHE sign from negative surface scattering-dominated AHE to positive interface scattering-dominated AHE, which is accompanied with the transition from anisotropy magnetoresistance (AMR) dominated transport to giant magnetoresistance (GMR) dominated transport. For n = 80, scaling analysis with Rs ∝ρ xx γ yields γ ∼ 3.44 for x = 0.52 which presents GMR-type transport, in contrast to γ ∼ 5.7 for x = 0 which presents AMR-type transport. © 2013 American Institute of Physics.

  11. Near-Field Plasmonic Behavior of Au/Pd Nanocrystals with Pd-Rich Tips

    CERN Document Server

    Ringe, Emilie; Collins, Sean M; Duchamp, Martial; Dunin-Borkowski, Rafal E; Skrabalak, Sara E; Midgley, Paul A

    2015-01-01

    Using nanometer spatial resolution electron-energy loss spectroscopy (EELS), energy dispersive X-ray spectroscopy (EDS), and cathodoluminescence (CL) mapping, we demonstrate that Au alloys containing a poor plasmonic metal (Pd) can nevertheless sustain multiple size-dependent localized surface plasmon resonances and observe strong field enhancement at Pd-rich tips, where the composition is in fact least favorable for plasmons. These Au/Pd stellated nanocrystals are also involved in substrate and interparticle coupling, as unraveled by EELS tilt series.

  12. Recovery of high-purity metallic Pd from Pd(II)-sorbed biosorbents by incineration.

    Science.gov (United States)

    Won, Sung Wook; Lim, Areum; Yun, Yeoung-Sang

    2013-06-01

    This work reports a direct way to recover metallic palladium with high purity from Pd(II)-sorbed polyethylenimine-modified Corynebacterium glutamicum biosorbent using a combined method of biosorption and incineration. This study is focused on the incineration part which affects the purity of recovered Pd. The incineration temperature and the amount of Pd loaded on the biosorbent were considered as major factors in the incineration process, and their effects were examined. The results showed that both factors significantly affected the enhancement of the recovery efficiency and purity of the recovered Pd. SEM-EDX and XRD analyses were used to confirm that Pd phase existed in the ash. As a result, the recovered Pd was changed from PdO to zero-valent Pd as the incineration temperature was increased from 600 to 900°C. Almost 100% pure metallic Pd was recovered with recovery efficiency above 99.0% under the conditions of 900°C and 136.9 mg/g.

  13. AGS experiments -- 1991, 1992, 1993. Tenth edition

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1994-04-01

    This report contains: (1) FY 1993 AGS schedule as run; (2) FY 1994--95 AGS schedule; (3) AGS experiments {ge} FY 1993 (as of 30 March 1994); (4) AGS beams 1993; (5) AGS experimental area FY 1991 physics program; (6) AGS experimental area FY 1992 physics program; (7) AGS experimental area FY 1993 physics program; (8) AGS experimental area FY 1994 physics program (planned); (9) a listing of experiments by number; (10) two-page summaries of each experiment; (11) listing of publications of AGS experiments; and (12) listing of AGS experiments.

  14. AGS experiments -- 1995, 1996 and 1997

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.; Presti, P.L.

    1997-12-01

    This report contains (1) FY 1995 AGS schedule as run; (2) FY 1996 AGS schedule as run; (3) FY 1997 AGS schedule as run; (4) FY 1998--1999 AGS schedule (proposed); (5) AGS beams 1997; (6) AGS experimental area FY 1995 physics program; (7) AGS experimental area FY 1996 physics program; (8) AGS experimental area FY 1997 physics program; (9) AGS experimental area FY 1998--1999 physics program (proposed); (10) a listing of experiments by number; (11) two-page summaries of each experiment, in order by number; and (12) listing of publications of AGS experiments.

  15. Induction of PD-L1 expression by epidermal growth factor receptor–mediated signaling in esophageal squamous cell carcinoma

    Science.gov (United States)

    Zhang, Wencheng; Pang, Qingsong; Yan, Cihui; Wang, Qifeng; Yang, Jingsong; Yu, Shufei; Liu, Xiao; Yuan, Zhiyong; Wang, Ping; Xiao, Zefen

    2017-01-01

    Purpose The purpose of this study was to investigate the potential effect of activation of epidermal growth factor receptor (EGFR) signaling pathway on the expression of programmed death-ligand 1 (PD-L1) in esophageal squamous cell carcinoma (ESCC) cells with EGFR overexpression. Methods Flow cytometry and Western blot methods were used to assess PD-L1 expression on ESCC cells when EGFR signaling pathway was activated by epidermal growth factor (EGF) with or without EGFR-specific inhibitor AG-1478, and then EGFR signaling array was applied to analyze the potential signaling pathways involved. Results This study found that PD-L1 expression increased significantly in an EGFR-dependent manner by the activation of EGFR signaling and decreased sharply when EGFR signaling was blocked. The upregulated expression of PD-L1 was not associated with EGFR-STAT3 signaling pathway, but may be affected by EGFR–PI3K–AKT, EGFR–Ras–Raf–Erk, and EGR–PLC-γ signaling pathways. Conclusion The expression of PD-L1 can be regulated by EGFR signaling activation in ESCC, which indicates an important role for EGFR-mediated immune escape and potential molecular pathways for EGFR-targeted therapy and immunotherapy.

  16. [Comparative analysis of PD25-V50 and PD20-FEV1 as a judgement of bronchial provocation test].

    Science.gov (United States)

    Yao, W Z; Zhoa, M W; Han, R X

    1994-08-01

    PD25-V50 as a judgement of bronchial provocation test was compared with PD20-FEV1. Both PD25-V50 and PD20-FEV1 showed linear correlation, but PD25-V50 was more sensitive than PD20-FEV1 for the diagnosis of bronchial asthma, and had higher specificity and sensitivity, and lower false-negative and false-positiverate. Moreover PD25-V50 provided the advantages of shorter period of histamine provocation and lower dose of inhaled histamine, so that avoided the side effects of higher dose of histamine.

  17. Designing and Validating Ternary Pd Alloys for Optimum Sulfur/Carbon Resistance in Hydrogen Separation and Carbon Capture Membrane Systems Using High-Throughput Combinatorial Methods

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Amanda [Pall Corporation, Port Washington, NY (United States); Zhao, Hongbin [Pall Corporation, Port Washington, NY (United States); Hopkins, Scott [Pall Corporation, Port Washington, NY (United States)

    2014-12-01

    This report summarizes the work completed under the U.S. Department of Energy Project Award No.: DE-FE0001181 titled “Designing and Validating Ternary Pd Alloys for Optimum Sulfur/Carbon Resistance in Hydrogen Separation and Carbon Capture Membrane Systems Using High-Throughput Combinatorial Methods.” The project started in October 1, 2009 and was finished September 30, 2014. Pall Corporation worked with Cornell University to sputter and test palladium-based ternary alloys onto silicon wafers to examine many alloys at once. With the specialized equipment at Georgia Institute of Technology that analyzed the wafers for adsorbed carbon and sulfur species six compositions were identified to have resistance to carbon and sulfur species. These compositions were deposited on Pall AccuSep® supports by Colorado School of Mines and then tested in simulated synthetic coal gas at the Pall Corporation. Two of the six alloys were chosen for further investigations based on their performance. Alloy reproducibility and long-term testing of PdAuAg and PdZrAu provided insight to the ability to manufacture these compositions for testing. PdAuAg is the most promising alloy found in this work based on the fabrication reproducibility and resistance to carbon and sulfur. Although PdZrAu had great initial resistance to carbon and sulfur species, the alloy composition has a very narrow range that hindered testing reproducibility.

  18. Designing and Validating Ternary Pd Alloys for Optimum Sulfur/Carbon Resistance in Hydrogen Separation and Carbon Capture Membrane Systems Using High-Throughput Combinatorial Methods

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Amanda; Zhao, Hongbin; Hopkins, Scott

    2014-09-30

    This report summarizes the work completed under the U.S. Department of Energy Project Award No.: DE-FE0001181 titled “Designing and Validating Ternary Pd Alloys for Optimum Sulfur/Carbon Resistance in Hydrogen Separation and Carbon Capture Membrane Systems Using High-Throughput Combinatorial Methods.” The project started in October 1, 2009 and was finished September 30, 2014. Pall Corporation worked with Cornell University to sputter and test palladium-based ternary alloys onto silicon wafers to examine many alloys at once. With the specialized equipment at Georgia Institute of Technology that analyzed the wafers for adsorbed carbon and sulfur species six compositions were identified to have resistance to carbon and sulfur species. These compositions were deposited on Pall AccuSep® supports by Colorado School of Mines and then tested in simulated synthetic coal gas at the Pall Corporation. Two of the six alloys were chosen for further investigations based on their performance. Alloy reproducibility and long-term testing of PdAuAg and PdZrAu provided insight to the ability to manufacture these compositions for testing. PdAuAg is the most promising alloy found in this work based on the fabrication reproducibility and resistance to carbon and sulfur. Although PdZrAu had great initial resistance to carbon and sulfur species, the alloy composition has a very narrow range that hindered testing reproducibility.

  19. Progress in Solving the Elusive Ag Transport Mechanism in TRISO Coated Particles: What is new?

    Energy Technology Data Exchange (ETDEWEB)

    Isabella Van Rooyen

    2014-10-01

    The TRISO particle for HTRs has been developed to an advanced state where the coating withstands internal gas pressures and retains fission products during irradiation and under postulated accidents. However, one exception is Ag that has been found to be released from high quality TRISO coated particles when irradiated and can also during high temperature accident heating tests. Although out- of- pile laboratory tests have never hither to been able to demonstrate a diffusion process of Ag in SiC, effective diffusion coefficients have been derived to successfully reproduce measured Ag-110m releases from irradiated HTR fuel elements, compacts and TRISO particles It was found that silver transport through SiC does not proceed via bulk volume diffusion. Presently grain boundary diffusion that may be irradiation enhanced either by neutron bombardment or by the presence of fission products such as Pd, are being investigated. Recent studies of irradiated AGR-1 TRISO fuel using scanning transmission electron microscopy (STEM), transmission kukuchi diffraction (TKD) patterns and high resolution transmission electron microscopy (HRTEM) have been used to further the understanding of Ag transport through TRISO particles. No silver was observed in SiC grains, but Ag was identified at triple-points and grain boundaries of the SiC layer in the TRISO particle. Cadmium was also found in some of the very same triple junctions, but this could be related to silver behavior as Ag-110m decays to Cd-110. Palladium was identified as the main constituent of micron-sized precipitates present at the SiC grain boundaries and in most SiC grain boundaries and the potential role of Pd in the transport of Ag will be discussed.

  20. Scaling of crystal field parameters between Pd 2REIn and Pd 2RESn

    Science.gov (United States)

    Babateen, M.; Neumann, K.-U.; Ziebeck, K. R. A.

    1995-02-01

    Experimentally it is found that crystal field (CF) parameters between the same rare earth compounds in the alloy series Pd 2REIn and Pd 2RESn (RE = rare earth element) exhibit scaling properties. A phenomenological model is put forward to explain this observation.

  1. Dehydrogenation of methanol on Pd(100): comparison with the results of Pd(111).

    Science.gov (United States)

    Jiang, Ruibin; Guo, Wenyue; Li, Ming; Lu, Xiaoqing; Yuan, Jianye; Shan, Honghong

    2010-07-28

    Dehydrogenation of methanol on Pd(100) is systematically investigated using self-consistent periodic density functional theory. The theoretical results are compared with those of the same reaction on Pd(111) published very recently [J. Phys. Chem. C, 2009, 113, 4188-4197]. Switching from (111) to (100), adsorptions are strengthened for most species except for CHO, CO and H at hollow sites. Moreover, Pd(100) affords relatively low energy barriers and higher rate constants for most elementary dehydrogenation steps as well as smaller desorption rates for the saturated adsorbates (methanol and formaldehyde), suggesting that the more open Pd surface indeed possesses the higher activity and selectivity for the complete dehydrogenation of methanol. At lower temperatures (e.g., 250 K), Pd(100) affords the same dehydrogenation path as Pd(111) for methanol, which is unchanged on the latter surface at both lower and higher temperatures; whereas at the typical steam re-forming (MSR) temperature (500 K), the path on Pd(100), i.e., CH(3)OH --> CH(3)O and/or CH(2)OH --> CH(2)O --> CHO --> CO, is different from the situation of Pd(111). In both cases, the initial bond scission process constitutes the rate-determining step.

  2. Double Beta Decays into Excited States in $^{110}$Pd and $^{102}$Pd

    CERN Document Server

    Lehnert, B; Degering, D; Hult, M; Laubenstein, M; Wester, T; Zuber, K

    2016-01-01

    A search for double beta decays of $^{110}$Pd and $^{102}$Pd into excited states of the daughter nuclides has been performed using three ultra-low background gamma-spectrometry measurements in the Felsenkeller laboratory, Germany, the HADES laboratory, Belgium and at the LNGS, Italy. The combined Bayesian analysis of the three measurements sets improved half-life limits for the $2\

  3. Ag transport in CrN-Ag nanocomposite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Mulligan, C.P. [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); U.S. Army Armament Research Development and Engineering Center, Benet Laboratories, Watervliet, NY 12189 (United States); Papi, P.A. [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Gall, D., E-mail: galld@rpi.edu [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

    2012-09-01

    2-{mu}m-thick CrN-Ag composite coatings containing 22 at.% Ag were deposited on Si(001) by reactive co-sputtering at T{sub s} = 300, 400, and 500 Degree-Sign C. Subsequent vacuum annealing at T{sub a} = 425, 525, and 625 Degree-Sign C causes Ag transport to the surface. Auger electron spectroscopy and plan-view microscopy are used to quantify the Ag transport to the surface, which increases strongly with increasing {Delta}T = T{sub a} - T{sub s}. Compositional depth profiles and cross-sectional microscopy show that annealing causes a negligible Ag gradient through the composite layer, suggesting that the Ag transport is detachment-limited as opposed to diffusion-limited. Statistical analyses of Ag aggregate size-distributions within the matrix show that large aggregates ({>=} 50 nm) are unaffected by annealing, while the Ag in a large fraction of small aggregates (< 50 nm) moves to the surface, leaving behind 10-50 nm wide voids in the annealed composite. This indicates that the Ag from the smaller grains, with a higher chemical potential and thus a higher detachment rate, is transferred to the large grains on the surface which are 200-1000 nm wide. - Highlights: Black-Right-Pointing-Pointer CrN-Ag coatings were deposited at T{sub s} = 300-500 Degree-Sign C and annealed at T{sub a} = 425-625 Degree-Sign C. Black-Right-Pointing-Pointer Ag diffuses from aggregates in the coating to the surface, if T{sub a} > T{sub s}. Black-Right-Pointing-Pointer During annealing, aggregates < 50 nm become voids, those > 50 nm are unaffected. Black-Right-Pointing-Pointer The Ag transport is detachment rather than diffusion limited.

  4. Domain structures and magnetization reversal in Co/Pd and CoFeB/Pd multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Sbiaa, R., E-mail: rachid@squ.edu.om [Department of Physics, Sultan Qaboos University, P.O. Box 36, PC 123 (Oman); Ranjbar, M. [Physics Department, University of Gothenburg, 412 96 Gothenburg (Sweden); Åkerman, J. [Physics Department, University of Gothenburg, 412 96 Gothenburg (Sweden); Materials Physics, School of ICT, Royal Institute of Technology (KTH), 164 40 Kista (Sweden)

    2015-05-07

    Domain structures and magnetization reversal of (Co/Pd) and (CoFeB/Pd) multilayers with 7 and 14 repeats were investigated. The Co-based multilayers show much larger coercivities, a better squareness, and a sharper magnetization switching than CoFeB-based multilayers. From magnetic force microscopy observations, both structures show strong reduction in domains size as the number of repeats increases but the magnetic domains for Co-based multilayers are more than one order of magnitude larger than for CoFeB-based multilayers. By imaging domains at different times, breaks in the (CoFeB/Pd) multilayer stripes were observed within only few hours, while no change could be seen for (Co/Pd) multilayers. Although CoFeB single layers are suitable for magnetoresistive devices due to their large spin polarization and low damping constants, their lamination with Pd suffers mainly from thermal instability.

  5. One-pot synthesis of Pd-Pt@Pd core-shell nanocrystals with enhanced electrocatalytic activity for formic acid oxidation

    KAUST Repository

    Yuan, Qiang

    2014-01-01

    Well-defined Pd-Pt@Pd core-shell nanocrystals with a Pd-Pt alloy core and a conformal Pd shell of ~2-3 nm were directly synthesized through a one-pot, aqueous solution approach without any preformed Pd or Pt seeds. These Pd-Pt@Pd core-shell nanocrystals show an enhanced electrocatalytic activity for formic acid oxidation compared with commercial Pd black. This journal is © 2014 The Royal Society of Chemistry.

  6. Preparation and antibacterial activities of Ag/Ag+/Ag3+ nanoparticle composites made by pomegranate (Punica granatum) rind extract

    Science.gov (United States)

    Yang, Hui; Ren, Yan-yu; Wang, Tao; Wang, Chuang

    Nano-silver and its composite materials are widely used in medicine, food and other industries due to their strong conductivity, size effect and other special performances. So far, more microbial researches have been applied, but a plant method is rarely reported. In order to open up a new way to prepare AgNP composites, pomegranate peel extract was used in this work to reduce Ag+ to prepare Ag/Ag+/Ag3+ nanoparticle composites. UV-Vis was employed to detect and track the reduction of Ag+ and the forming process of AgNPs. The composition, structure and size of the crystal were analyzed by XRD and TEM. Results showed that, under mild conditions, pomegranate peel extract reacted with dilute AgNO3 solution to produce Ag/Ag+/Ag3+ nanoparticle composites. At pH = 8 and 10 mmol/L of AgNO3 concentration, the size of the achieved composites ranged between 15 and 35 nm with spherical shapes and good crystallinity. The bactericidal experiment indicated that the prepared Ag/Ag+/Ag3+ nanoparticles had strong antibacterial activity against gram positive bacteria and gram negative bacteria. FTIR analysis revealed that biological macromolecules with groups of sbnd NH2, sbnd OH, and others were distributed on the surface of the newly synthesized Ag/Ag+/Ag3+ nanoparticles. This provided a useful clue to further study the AgNP biosynthesis mechanism.

  7. Dissolution and Interface Reactions between Palladium and Tin (Sn)-Based Solders: Part I. 95.5Sn-3.9Ag-0.6Cu Alloy

    Science.gov (United States)

    Vianco, Paul T.; Rejent, Jerome A.; Zender, Gary L.; Hlava, Paul F.

    2010-12-01

    The interface microstructures and dissolution behavior were studied, which occur between 99.9 pct Pd substrates and molten 95.5Sn-3.9Ag-0.6Cu (wt pct, Sn-Ag-Cu) solder. The solder bath temperatures were 513 K to 623 K (240 °C to 350 °C). The immersion times were 5 to 240 seconds. The IMC layer composition exhibited the (Pd, Cu)Sn4 (Cu, 0 to 2 at. pct) and (Pd, Sn) solid-solution phases for all test conditions. The phases PdSn and PdSn2 were observed only for the 623 K (350 °C), 60 seconds test conditions. The metastable phase, Pd11Sn9, occurred consistently for the 623 K (350 °C), 240 seconds conditions. Palladium-tin needles appeared in the Sn-Ag-Cu solder, but only at temperatures of 563 K (290 °C ) or higher, and had a (Pd, Cu)Sn4 stoichiometry. Palladium dissolution increased monotonically with both solder bath temperature and exposure time. The rate kinetics of dissolution were represented by the expression At n exp(∆ H/R T), where the time exponent ( n) was 0.52 ± 0.10 and the apparent activation energy (∆ H) was 44 ± 9 kJ/mol. The IMC layer thickness increased between 513 K and 563 K (240 °C and 290 °C) to approximately 3 to 5 µm, but then was less than 3 µm at 593 K and 623 K (320 °C and 350 °C). The thickness values exhibited no significant time dependence. As a protective finish in electronics assembly applications, Pd would be relatively slow to dissolve into molten Sn-Ag-Cu solder. The Pd-Sn IMC layer would remain sufficiently thin and adherent to a residual Pd layer so as to pose a minimal reliability concern for Sn-Ag-Cu solder interconnections.

  8. PD-L1 Expression in Lung Cancer

    Science.gov (United States)

    Yu, Hui; Boyle, Theresa A.; Zhou, Caicun; Rimm, David L.; Hirsch, Fred R.

    2017-01-01

    Immunotherapies targeted against programmed death ligand 1 (PD-L1) and its receptor (PD-1) have improved survival in a subset of patients with advanced lung cancer. PD-L1 protein expression has emerged as a biomarker that predicts which patients are more likely to respond to immunotherapy. The understanding of PD-L1 as a biomarker is complicated by the history of use of different immunohistochemistry platforms with different PD-L1 antibodies, scoring systems, and positivity cut-offs for immunotherapy clinical trials with different anti-PD-L1 and anti-PD-1 drugs. Herein, we summarize the brief history of PD-L1 as a biomarker and describe the challenges remaining to harmonize PD-L1 detection and interpretation for best patient care. PMID:27117833

  9. Understanding Physical Developer (PD): Part II--Is PD targeting eccrine constituents?

    Science.gov (United States)

    de la Hunty, Mackenzie; Moret, Sébastien; Chadwick, Scott; Lennard, Chris; Spindler, Xanthe; Roux, Claude

    2015-12-01

    Physical developer (PD) is a fingermark development technique that deposits silver onto fingermark ridges. It is the only technique currently in routine operational use that gives results on porous substrates that have been wet. There is a reasonable understanding of the working solution chemistry, but the chemical constituent(s) contained in fingermark residue that are specifically targeted by PD are largely unknown. A better understanding of the PD technique will permit a more informed selection of alternative or complementary detection methods, and greater usage in operational laboratories. Recent research by our group has shown that PD does not selectively target the lipids present in the residue. This research investigated the hypothesis that PD targets the eccrine constituents in fingermark residue. This was tested by comparison of PD and indanedione-zinc (Ind-Zn) treated natural fingermarks that had been deposited successively, and marks that had been deposited with a ten second interval in between depositions. Such an interval allows for the regeneration of secretions from the pores located on the ridges of the fingers. On fingermark depletions with no time interval between depositions, PD and Ind-Zn treated depletions successively (and comparatively) decreased in development intensity as the amount of residue diminished. Short time intervals in between successive depletions resulted in additional secretions from the pores intermittently occurring, the increased development of which was visualised by treatment with both PD and Ind-Zn. The changes in development intensity were seen with both techniques on the same split depletions in a series, comparably and proportionately. These results indicate that the components targeted by PD are contained in the material excreted by the friction ridge pores through its mirrored development with Ind-Zn. Repetition of the experiments on marks that only contained eccrine material showed good Ind-Zn development but poor

  10. Nitrite reduction mechanism on a Pd surface.

    Science.gov (United States)

    Shin, Hyeyoung; Jung, Sungyoon; Bae, Sungjun; Lee, Woojin; Kim, Hyungjun

    2014-11-04

    Nitrate (NO3-) is one of the most harmful contaminants in the groundwater, and it causes various health problems. Bimetallic catalysts, usually palladium (Pd) coupled with secondary metallic catalyst, are found to properly treat nitrate-containing wastewaters; however, the selectivity toward N2 production over ammonia (NH3) production still requires further improvement. Because the N2 selectivity is determined at the nitrite (NO2-) reduction step on the Pd surface, which occurs after NO3- is decomposed into NO2- on the secondary metallic catalyst, we here performed density functional theory (DFT) calculations and experiments to investigate the NO2- reduction pathway on the Pd surface activated by hydrogen. Based on extensive DFT calculations on the relative energetics among ∼100 possible intermediates, we found that NO2- is easily reduced to NO* on the Pd surface, followed by either sequential hydrogenation steps to yield NH3 or a decomposition step to N* and O* (an adsorbate on Pd is denoted using an asterisk). Based on the calculated high migration barrier of N*, we further discussed that the direct combination of two N* to yield N2 is kinetically less favorable than the combination of a highly mobile H* with N* to yield NH3. Instead, the reduction of NO2- in the vicinity of the N* can yield N2O* that can be preferentially transformed into N2 via diverse reaction pathways. Our DFT results suggest that enhancing the likelihood of N* encountering NO2- in the solution phase before combination with surface H* is important for maximizing the N2 selectivity. This is further supported by our experiments on NO2- reduction by Pd/TiO2, showing that both a decreased H2 flow rate and an increased NO2- concentration increased the N2 selectivity (78.6-93.6% and 57.8-90.9%, respectively).

  11. Ni/Pd-Decorated Carbon NFs as an Efficient Electrocatalyst for Methanol Oxidation in Alkaline Medium

    Science.gov (United States)

    Mohamed, Ibrahim M. A.; Khalil, Khalil Abdelrazek; Mousa, Hamouda M.; Barakat, Nasser A. M.

    2017-01-01

    In this study, Ni/Pd-decorated carbon nanofibers (NFs) were fabricated as an electrocatalyst for methanol oxidation. These NFs were synthesized based on carbonization of poly(vinyl alcohol), which has high carbon content compared to many polymers used to prepare carbon NFs. Typically, calcination of an electrospun mat composed of nickel acetate, palladium acetate, and poly(vinyl alcohol) can produce Ni/Pd-doped carbon NFs. The introduced NFs were characterized by scanning electron microscopy, transmission electron microscopy (TEM), high-resolution transmission electron microscopy, line TEM energy dispersive x-ray spectrometry, field emission scanning electron microscopy, and x-ray powder diffraction. These physicochemical characterizations are acceptable tools to investigate the crystallinity and chemistry of the fabricated Ni/Pd-carbon NFs. Accordingly, the prepared NFs were tested to enhance the economic and catalytic behavior of methanol electrooxidation. Experimentally, the obtained onset potential was small compared to many reported materials; 0.32 V (versus Ag/AgCl as a reference electrode). At the same time, the current density changed from 5.08 mA/cm2 in free methanol at 0.6 V to 12.68 mA/cm2 in 0.1 mol/L methanol, which can be attributed to the MeOH oxidation. Compared to nanoparticles, the NFs have a distinct effect on the electrocatalytic performance of material due to the effect of the one-dimensional structure, which facilitates the electron transfer. Overall, the presented work opens a new way for non-precious one-dimensional nanostructured catalysts for direct methanol fuel cell technology.

  12. Ni/Pd-Decorated Carbon NFs as an Efficient Electrocatalyst for Methanol Oxidation in Alkaline Medium

    Science.gov (United States)

    Mohamed, Ibrahim M. A.; Khalil, Khalil Abdelrazek; Mousa, Hamouda M.; Barakat, Nasser A. M.

    2016-09-01

    In this study, Ni/Pd-decorated carbon nanofibers (NFs) were fabricated as an electrocatalyst for methanol oxidation. These NFs were synthesized based on carbonization of poly(vinyl alcohol), which has high carbon content compared to many polymers used to prepare carbon NFs. Typically, calcination of an electrospun mat composed of nickel acetate, palladium acetate, and poly(vinyl alcohol) can produce Ni/Pd-doped carbon NFs. The introduced NFs were characterized by scanning electron microscopy, transmission electron microscopy (TEM), high-resolution transmission electron microscopy, line TEM energy dispersive x-ray spectrometry, field emission scanning electron microscopy, and x-ray powder diffraction. These physicochemical characterizations are acceptable tools to investigate the crystallinity and chemistry of the fabricated Ni/Pd-carbon NFs. Accordingly, the prepared NFs were tested to enhance the economic and catalytic behavior of methanol electrooxidation. Experimentally, the obtained onset potential was small compared to many reported materials; 0.32 V (versus Ag/AgCl as a reference electrode). At the same time, the current density changed from 5.08 mA/cm2 in free methanol at 0.6 V to 12.68 mA/cm2 in 0.1 mol/L methanol, which can be attributed to the MeOH oxidation. Compared to nanoparticles, the NFs have a distinct effect on the electrocatalytic performance of material due to the effect of the one-dimensional structure, which facilitates the electron transfer. Overall, the presented work opens a new way for non-precious one-dimensional nanostructured catalysts for direct methanol fuel cell technology.

  13. Targeting the PD-1/PD-L1 axis in the treatment of lung cancer

    Directory of Open Access Journals (Sweden)

    Matikas Alexios

    2016-03-01

    Full Text Available In recent years major advances in the field of molecular profiling of non-small cell lung cancer led to the identification of targetable driver mutations and revolutionized the treatment of specific patient subsets. However, the majority of NSCLC tumors do not harbor these genomic events. On the other hand, current studies have confirmed an expanding role for immunotherapy in lung cancer and new agents, such as inhibitors of the programmed cell death-1 (PD-1/programmed cell death ligand 1 (PD-L1 axis have been introduced in the treatment armamentarium. The monoclonal antibodies nivolumab and pembrolizumab targeting PD-1 resulted in superior survival when compared to standard second line chemotherapy within the context of randomized trials and received regulatory approval. Moreover, several other anti-PD-L1 antibodies have demonstrated encouraging preliminary efficacy and multiple clinical trials in various settings during the disease trajectory are currently underway. Early immunotherapy trials have also illustrated the potential of PD-1 blockade in small cell lung cancer treatment, a disease for which major advances in systemic therapy are lacking. The currently available clinical data on PD-1/PD-L1 inhibition in lung cancer are summarized in this review.

  14. Ag-Air Service

    Science.gov (United States)

    1981-01-01

    Econ, Inc.'s agricultural aerial application, "ag-air," involves more than 10,000 aircraft spreading insecticides, herbicides, fertilizer, seed and other materials over millions of acres of farmland. Difficult for an operator to estimate costs accurately and decide what to charge or which airplane can handle which assignment most efficiently. Computerized service was designed to improve business efficiency in choice of aircraft and determination of charge rates based on realistic operating cost data. Each subscriber fills out a detailed form which pertains to his needs and then receives a custom-tailored computer printout best suited to his particular business mix.

  15. Construction of Ag/AgCl nanostructures from Ag nanoparticles as high-performance visible-light photocatalysts

    Science.gov (United States)

    Yang, Fan; Liu, Dongzhi; Wang, Tianyang; Li, Wei; Hu, Wenping; Zhou, Xueqin

    2016-11-01

    A combined strategy of in situ oxidation and assembly is developed to prepare Ag/AgCl nanospheres and nanocubes from Ag nanoparticles under room temperature. It is a new facile way to fabricate Ag/AgCl with small sizes and defined morphologies. Ag/AgCl nanospheres with an average size of 80 nm were achieved without any surfactants, while Ag/AgCl nanocubes with a mean edge length of 150 nm were obtained by introduction of N-dodecyl- N, N-dimethyl-2-ammonio-acetate. The possible formation mechanism involves the self-assembly of AgCl nanoparticles, Ostwald ripening and photoreduction of Ag+ into Ag0 by the room light. The as-prepared Ag/AgCl nanospheres and nanocubes exhibit excellent photocatalytic activity and stability toward degradation of organic pollutants under visible-light irradiation. It is demonstrated that Ag/AgCl nanocubes display enhanced photocatalytic activity in comparison with Ag/AgCl nanospheres due to the more efficient charge transfer. This work may pave an avenue to construct various functional materials via the assembly strategy using nanoparticles as versatile building blocks.

  16. Targeting the PD-1/PD-L1 axis in non-small cell lung cancer.

    Science.gov (United States)

    Kumar, Rajiv; Collins, Dearbhaile; Dolly, Saoirse; McDonald, Fiona; O'Brien, Mary E R; Yap, Timothy A

    2016-12-23

    The last decade has witnessed rapid advances in the discovery and development of immune checkpoint inhibitors in cancer medicine, particularly drugs targeting programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) in non-small cell lung cancer (NSCLC). The proven antitumor efficacy coupled with low rates of drug-related toxicities observed, albeit idiosyncratic, with these novel immunotherapeutics have led to the registration of multiple PD-1 and PD-L1 inhibitors, such as nivolumab, pembrolizumab, and atezolizumab, in second-line advanced NSCLC, whereas durvalumab and avelumab are in late-phase clinical testing. Moreover, pembrolizumab has shown a survival advantage in the first-line setting; however, nivolumab failed to show a survival benefit possibly relating to patient selection based on PD-L1 expression. Current patient selection is based on PD-L1 expression, using the relevant companion diagnostic test, where patients with strong PD-L1 expression being more likely to respond to these novel agents. Ongoing clinical research focuses on the development of PD-1 and PD-L1 inhibitor monotherapy in neoadjuvant and adjuvant NSCLC. There is also much interest in using these drugs as a therapeutic backbone for rational combinations with other treatment modalities including cytotoxic chemotherapies in the first-line NSCLC, other immunotherapies such as cytotoxic T-lymphocyte-associated protein 4 antagonists, molecularly targeted agents including EGFR and ALK inhibitors, and radiotherapy. Concurrent treatment with radiotherapy is of particular interest owing to the potential for the abscopal effect, using radiotherapy to facilitate systemic treatment.

  17. Preparation of Core-shell Cu-Ag Bimetallic Powder via Electroless Coating

    Institute of Scientific and Technical Information of China (English)

    XU Rui; ZHOU Kanggen; HU Minyi

    2009-01-01

    A novel method of electroless silver coating on copper powders was reported,in which hydrazine was used as the reducing agent,and had some advantages such was used as inhib-iting the substitution reaction and reducing consumption of copper powders.In the processes of sen-sitization and activation,AgNO_3 replaces the conventional PdCl_2,which solves the impurity of bath.Oxide film on the surface of copper powders was tested by chemical analysis.Ag element tested by XRD and XRF is in the form of Ag~0 and exists on the surface of copper powders,which acts as catalyzer in reduction reaction.Morphology and composition of the coating were characterized by SEM and XRD respectively.

  18. Understanding physical developer (PD): Part I--Is PD targeting lipids?

    Science.gov (United States)

    de la Hunty, Mackenzie; Moret, Sébastien; Chadwick, Scott; Lennard, Chris; Spindler, Xanthe; Roux, Claude

    2015-12-01

    Physical developer (PD) is a fingermark development technique that involves the selective reduction of silver onto fingermark residue. PD can develop marks on porous substrates even if they have been wet, leading to the logical, long held belief that the reagent targets the water insoluble constituents in the fingermark residue. The present research has tested this hypothesis as part of a broader study that aims to identify the targets of physical developer. Spot tests of some fatty acids, cholesterol and squalene, treated with PD, showed that only cholesterol produced significant silver deposition. PD is known to be particularly effective on aged marks, however cholesterol degrades over time. These observations indicate that PD reactivity with fingermarks cannot solely be due to the presence of cholesterol. Fingermarks were deposited on paper and washed with various organic solvents before being treated with PD. PD effectiveness was intermittent on both solvent washed and unwashed sides of both natural and groomed marks; however, it was seen to effectively develop groomed samples that had been exposed to common lipid extraction solvents, shown to have removed the lipids by visualisation using the lipid stain Nile red. PD effectiveness was most affected by exposure of samples to solvents that could dissolve water soluble components, showing that the removal of these constituents (by either water, or other solvents) decreases the amount of silver deposited on the fingermark residue by the working solution. Close observation of PD developed samples showed variation in silver deposition uniformity when comparing a developed ridge to a pore site located on that ridge. Some samples showed an absence of silver, and other showed an increase of silver at pore locations. This indicates that the material excreted by the pores on the finger has an effect on silver deposition, suggesting that PD may be specifically targeting eccrine constituents that are present along the

  19. The valence band structure of Ag{sub x}Rh{sub 1–x} alloy nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Anli [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science (NIMS), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 7 Goban-cho, Chiyoda-ku, Tokyo 102-0076 (Japan); Sakata, Osami, E-mail: SAKATA.Osami@nims.go.jp [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science (NIMS), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 7 Goban-cho, Chiyoda-ku, Tokyo 102-0076 (Japan); Synchrotron X-ray Group, Quantum Beam Unit, NIMS, 1-1-1 Kouto, Sayo-cho, Hyogo 679-5148 (Japan); Kusada, Kohei; Kobayashi, Hirokazu [Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 7 Goban-cho, Chiyoda-ku, Tokyo 102-0076 (Japan); Division of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Yayama, Tomoe; Ishimoto, Takayoshi [Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 7 Goban-cho, Chiyoda-ku, Tokyo 102-0076 (Japan); INAMORI Frontier Research Center, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Yoshikawa, Hideki [Surface Chemical Analysis Group, Nano Characterization Unit, NIMS, 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Koyama, Michihisa [Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 7 Goban-cho, Chiyoda-ku, Tokyo 102-0076 (Japan); INAMORI Frontier Research Center, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); International Institute for Carbon-Neutral Energy Research, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); and others

    2014-10-13

    The valence band (VB) structures of face-centered-cubic Ag-Rh alloy nanoparticles (NPs), which are known to have excellent hydrogen-storage properties, were investigated using bulk-sensitive hard x-ray photoelectron spectroscopy. The observed VB spectra profiles of the Ag-Rh alloy NPs do not resemble simple linear combinations of the VB spectra of Ag and Rh NPs. The observed VB hybridization was qualitatively reproduced via a first-principles calculation. The electronic structure of the Ag{sub 0.5}Rh{sub 0.5} alloy NPs near the Fermi edge was strikingly similar to that of Pd NPs, whose superior hydrogen-storage properties are well known.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-10-20

    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.

  1. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>AgEcon Search is a free,open access repository of full-text scholarly literature in agricultural and applied economics,including working papers,conference papers,and journal articles. AgEcon Search is co-sponsored by the Department of Applied Economics and

  2. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>AgEcon Search is a free,open access repository of full-text scholarly literature in agricultural and applied economics,including working papers,conference papers,and journal articles.AgEcon Search is co-sponsored by the Department of Applied Economics andthe University Libraries

  3. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>AgEcon Search is a free,open access repository of full-text scholarly literature in agricultural and applied economics,including working papers,conference papers,and journal articles. AgEcon Search is cosponsored by the Department of Applied Economics and the University Libraries at University of Minnesota and the Agricultural and Applied Economics Association.

  4. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>AgEcon Search is a free,open access repository of full-text scholarly literature in agricultural and applied economics,including working papers,conference papers,and journal articles. AgEcon Search is co-sponsored by the Department of Applied Economics and the University Libraries at University of Minnesota and the Agricultural and Applied

  5. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>AgEcon Search is a free,open access repository of full-text scholarly literature in agricultural and applied economics,including working papers,conference papers,and journal articles.AgEcon Search is co-sponsored by the Department of Applied Economics and the University Libraries

  6. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>AgEcon Search is a free,open access repository of full-text scholarly literature in agricultural and applied economics,including working papers,conference papers,and journal articles. AgEcon Search is co-sponsored by the Department of Applied Economics and the University Libraries at University of Minnesota and the Agricultural and Applied Economics Association. Research

  7. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>AgEcon Search is a free,open access repository of full-text scholarly literature in agricultural and applied economics,including working papers,conference papers,and journal articles. AgEcon Search is co-sponsored by the Department of Applied E-

  8. AGS Experiments: 1989, 1990, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1992-02-01

    This report contains: Experimental areas layout; table of beam parameters and fluxes; experiment schedule ``as run``; proposed 1992 schedule; a listing of experiments by number; two-page summaries of each experiment begin here, also ordered by number; publications of AGS Experiments begin here; and list of AGS Experimenters begins here.

  9. AGS Experiments: 1989, 1990, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1992-02-01

    This report contains: Experimental areas layout; table of beam parameters and fluxes; experiment schedule as run''; proposed 1992 schedule; a listing of experiments by number; two-page summaries of each experiment begin here, also ordered by number; publications of AGS Experiments begin here; and list of AGS Experimenters begins here.

  10. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>AgEcon Search is a free, open access repository of full-text scholarly literature in agricultural and applied economics, including working papers, conference papers, and journal articles.AgEcon Searchis co-sponsored by the Department of Applied E

  11. On the twinning in ZnPd.

    Science.gov (United States)

    Ivarsson, Dennis C A; Burkhardt, Ulrich; Heggen, Marc; Ormeci, Alim; Armbrüster, Marc

    2017-02-22

    The intermetallic compound ZnPd has demonstrated excellent catalytic properties in methanol steam reforming. While it is known that defects and microstructures influence the catalytic properties, little is known about the defects occurring in ZnPd. Due to recent advances in synthetic methods, coarse-grained ZnPd samples are accessible. This enables the detection and investigation of twinning in ZnPd by studying the twinned regions from the macroscopic scale by polarised light and electron backscattering diffraction (EBSD) down to the atomic scale by high-resolution transmission electron microscopy (HR-TEM). Twinning occurs in {101} and is coupled with a change in the c/a ratio in the vicinity of the twin boundary. Quantum chemical calculations result in only very small energy differences between the ideal and the twinned structure, explaining the experimentally observed thermal stability of the latter. The chemical bonding was investigated by the electron localizability indicator (ELI) and compared to the one in the ideal structure. The results confirm twinning along the {101} plane and demonstrate the high stability of the twin boundaries after formation.

  12. Novel SEU hardened PD SOI SRAM cell

    Institute of Scientific and Technical Information of China (English)

    Xie Chengmin; Wang Zhongfang; Wang Xihu; Wu Longsheng; Liu Youbao

    2011-01-01

    A novel SEU hardened 10T PD SOI SRAM cell is proposed.By dividing each pull-up and pull-down transistor in the cross-coupled inverters into two cascaded transistors,this cell suppresses the parasitic BJT and source-drain penetration charge collection effect in PD SOl transistor which causes the SEU in PD SOI SRAM.Mixed-mode simulation shows that this novel cell completely solves the SEU,where the ion affects the single transistor.Through analysis of the upset mechanism of this novel cell,SEU performance is roughly equal to the multiple-cell upset performance of a normal 6T SOI SRAM and it is thought that the SEU performance is 17 times greater than traditional 6T SRAM in 45nm PD SOI technology node based on the tested data of the references.To achieve this,the new cell adds four transistors and has a 43.4% area overhead and performance penalty.

  13. High Magnetization FeCo/Pd multilayers

    Science.gov (United States)

    Walock, Michael; Klose, Frank; Chshiev, Mairbek; Mankey, Gary; Butler, William

    2007-03-01

    A high saturation magnetization is advantageous in magnetic recording. Currently, the peak of the Slater-Pauling curve is the BCC FeCo system with a saturation magnetization of 2.45 T. Recently, a magnetization of 2.57 T in the FeCo layers of a [40 nm Fe30Co70 /1.7 nm Pd]x25 superlattice has been reported [1, 2]. This behavior may be attributed to an enhanced Fe moment in the expanded FCC matrix, and an accompanying induced moment in the Pd. Our theoretical calculations show an atomic moment enhancement, but this is not great enough to overcome the overall magnetization density reduction caused by the incorporation of Pd in the matrix. The overall effect is a reduced magnetization. Through variation of the FeCo composition and Pd layer thickness, and the combinatorial methods of structural and magnetic characterization, we will gain insight into the magnetic structure of this tertiary thin film system. [1] K. Noma, M. Matsuoka, H. Kanai, Y. Uehara, K. Nomura, and N. Awaji. IEEE Trans. Magn. 42, 140 (2006). [2] ibid. 41, 2920 (2005).

  14. Plasmonic Ag2MoO4/AgBr/Ag composite: Excellent photocatalytic performance and possible photocatalytic mechanism

    Science.gov (United States)

    Wang, Zhongliao; Zhang, Jinfeng; Lv, Jiali; Dai, Kai; Liang, Changhao

    2017-02-01

    Plasmonic Ag2MoO4/AgBr/Ag composite is fabricated by in-situ ion exchange and reduction methods at room temperature. The samples are characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance (DRS), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscope (SEM) and photoluminescence (PL) measurements. The results show that butterfly-like Ag2MoO4 nanosheets served as the precursor, and Ag2MoO4/AgBr/Ag is formed in phase transformation with MoO42- displaced by Br-. The ternary Ag2MoO4/AgBr/Ag composite photocatalysts show greatly enhanced photocatalytic activity in photodegrading methylene blue (MB) under visible light irradiation compared with AgBr and Ag2MoO4. The pseudo-first-order rate constant kapp of Ag2MoO4/AgBr/Ag is 0.602 min-1, which is 11.6 and 18.3 times as high as that of AgBr and Ag2MoO4, respectively. Meanwhile, the efficiency of degradation still kept 90% after ten times cyclic experiments. Eventually, possible photocatalytic mechanism was proposed.

  15. State of Supported Pd during Catalysis in Water

    Energy Technology Data Exchange (ETDEWEB)

    Chase, Zizwe; Fulton, John L.; Camaioni, Donald M.; Mei, Donghai; Balasubramanian, Mahalingam; Pham, Van Thai; Zhao, Chen; Weber, Robert S.; Wang, Yong; Lercher, Johannes A.

    2013-08-29

    In operando X-ray absorption was used to measure the structure and chemical state of supported Pd nanoparticles with 3 -10 nm diameter in contact with H2 saturated water at 298-473 K. The Pd-Pd distances determined were consistent with the presence of subsurface hydrogen, i.e., longer than those measured by others for bare, reduced Pd particles, and within the range of distances for Pd hydrides. During the Pd-catalyzed hydrogenation of phenol, cyclohexanone, cyclohexanol or cyclohexene in the presence of water, the Pd nanoparticles exhibited a lengthening of the Pd-Pd bond that we attribute to a change in the concentration of sorbed H related to the steady state of H at the surface of the Pd particles. This steady state is established by all reactions involving H2, i.e., the sorption/desorption into the bulk, the sorption at the surface, and the reaction with adsorbed unsaturated reactants. Thus, first insight into the chemical state of Pd and the H/Pd ratio during catalysis in water is provided. The Pd particles did not change upon their exposure to water or reactants; nor did the spectra show any effect from the interaction of the Pd particles with various supports. The experimental results are consistent with ab initio molecular dynamic simulations, which indicate that Pd-water interactions are relatively weak for Pd metal and that these interactions become even weaker, when hydrogen is incorporated into the metal particles. This work was supported by the US Department of Energy (DOE), Office of Basic Energy Sciences (BES), Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory is a multi-program national laboratory operated for DOE by Battelle through Contract DE-AC05-76RL01830.

  16. One-step Solution Processing of Ag, Au and Pd@MXene Hybrids for SERS

    Science.gov (United States)

    Satheeshkumar, Elumalai; Makaryan, Taron; Melikyan, Armen; Minassian, Hayk; Gogotsi, Yury; Yoshimura, Masahiro

    2016-08-01

    We report on one-step hybridization of silver, gold and palladium nanoparticles from solution onto exfoliated two-dimensional (2D) Ti3C2 titanium carbide (MXene) nanosheets. The produced hybrid materials can be used as substrates for surface-enhanced Raman spectroscopy (SERS). An approximate analytical approach is also developed for the calculation of the surface plasmon resonance (SPR) frequency of nanoparticles immersed in a medium, near the interface of two dielectric media with different dielectric constants. We obtained a good match with the experimental data for SPR wavelengths, 440 nm and 558 nm, respectively for silver and gold nanoparticles. In the case of palladium, our calculated SPR wavelength for the planar geometry was 160 nm, demonstrating that non-spherical palladium nanoparticles coupled with 2D MXene yield a broad, significanlty red-shifted SPR band with a peak at 230 nm. We propose a possible mechanism of the plasmonic hybridization of nanoparticles with MXene. The as-prepared noble metal nanoparticles on MXene show a highly sensitive SERS detection of methylene blue (MB) with calculated enhancement factors on the order of 105. These findings open a pathway for extending visible-range SERS applications of novel 2D hybrid materials in sensors, catalysis, and biomedical applications.

  17. Multi-metallic Nanomaterials From Ni, Ag, Pd With Pt's Catalytic Activity

    KAUST Repository

    Huang, Kuo-Wei

    2015-06-04

    A trimetallic catalyst that is a combination of nickel, silver and palladium metal is described. The trimetallic catalyst can be used to produce hydrogen and is useful as a replacement for platinum in hydrogenation reactions.

  18. Investigation of Pd0.8Ag0.2 Intermetallic Compound Hydrides by Pertur

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    2.5InvestigationofPd_(0.8)Ag_(0.2)IntermetallicCompoundHydridesbyPerturbedAngularCorrelativeMethodChengFeng;GouZhehui;ZhengSh...

  19. Characterization and functionalities of Pd/hydrotalcite catalysts

    Science.gov (United States)

    Naresh, Dhachapally; Kumar, Vanama Pavan; Harisekhar, Mitta; Nagaraju, Nekkala; Putrakumar, Balla; Chary, Komandur V. R.

    2014-09-01

    A series of palladium supported on calcined hydrotalcite (CHT) catalysts with varying palladium (Pd) loadings (1.0-8.0 wt%) were prepared by impregnation method. Their catalytic performance was evaluated for the reductive amination of phenol to aniline that showed a tremendous interest in the chemical industry. The catalysts were characterized by BET surface area, XRD, TEM, XPS, TPR of H2, TPD of CO2 and CO chemisorption. BET surface area decreased continuously with increase in Pd content. XRD results confirmed the changes in the crystalline phases with altering Pd content. TEM results showed the formation of fine particles at lower loadings and agglomerates at higher loadings. TPR profiles revealed that the reducibility increases with increase of Pd loading. CO2 TPD results illustrate the catalysts basicity increases with increase of Pd loading up to 4.0 wt% and decreases at higher loadings. Pd dispersion, metal area and crystallite sizes were determined by CO chemisorption method. Pd dispersion and metal area decreases with increase of Pd content and crystallite sizes. The results demonstrated that the Pd dispersion and basic properties are depending on the Pd loading. The catalytic performance clearly showed that the increase Pd loading the conversion of phenol increased up to 2.0 wt% and level off beyond the loading. The catalytic properties are well correlated with the active Pd sites determined by CO chemisorption, dispersion and basicity.

  20. Radiochemical synthesis of {sup 105g}Ag-labelled silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ichedef, C., E-mail: cigdem_ch@yahoo.com; Simonelli, F.; Holzwarth, U. [Institute for Health and Consumer Protection, European Commission, Joint Research Centre (Italy); Bagaria, J. Piella; Puntes, V. F. [Institut Català de Nanotecnologia (ICN2) (Spain); Cotogno, G.; Gilliland, D.; Gibson, N. [Institute for Health and Consumer Protection, European Commission, Joint Research Centre (Italy)

    2013-11-15

    A method for synthesis of radiolabelled silver nanoparticles is reported. The method is based on proton activation of silver metal powder, enriched in {sup 107}Ag, with a 30.7 MeV proton beam. At this proton energy {sup 105g}Ag is efficiently created, mainly via the {sup 107}Ag(p,3n){sup 105}Cd → {sup 105g}Ag reaction. {sup 105g}Ag has a half-life of 41.29 days and emits easily detectable gamma radiation on decay to {sup 105}Pd. This makes it very useful as a tracing radionuclide for experiments over several weeks or months. Following activation and a period to allow short-lived radionuclides to decay, the powder was dissolved in concentrated nitric acid in order to form silver nitrate (AgNO{sub 3}), which was used to synthesise radiolabelled silver nanoparticles via the process of sodium borohydride reduction. For comparison, non-radioactive silver nanoparticles were synthesised using commercially supplied AgNO{sub 3} in order to check if the use of irradiated Ag powder as a starting material would alter in any way the final nanoparticle characteristics. Both nanoparticle types were characterised using dynamic light scattering, zeta-potential and X-ray diffraction measurements, while additionally the non-radioactive samples were analysed by transmission electron microscopy and UV–Vis spectrometry. A hydrodynamic diameter of about 16 nm was determined for both radiolabelled and non-radioactive nanoparticles, while the electron microscopy on the non-radioactive samples indicated that the physical size of the metal NPs was (7.3 ± 1.4) nm.

  1. Luminescent molecular Ag-S nanocluster [Ag(62)S(13)(SBu(t))(32)](BF(4))(4).

    Science.gov (United States)

    Li, Gen; Lei, Zhen; Wang, Quan-Ming

    2010-12-22

    The first observation of luminescence from a structurally well-defined Ag(2)S molecular nanocluster is reported. Reaction of AgSBu(t)/AgBF(4) with N(2)H(4) in methanol affords the tetracationic cluster [Ag(62)S(13)(SBu(t))(32)](BF(4))(4), which has a core-shell configuration. The 14 silver(I) centers of the [Ag(14)S(13)] core are in a face-centered cubic arrangement with each edge bridged by a S(2-) ligand; the core is further connected to the [Ag(48)(SBu(t))(32)] shell via both Ag-S bonds and Ag···Ag interactions. This novel cluster displays intense red emission in both the solid state and solution at room temperature.

  2. Characterization of the active site structure of Pd and Pd-promoted Mo sulfide catalysts by means of XAFS.

    Science.gov (United States)

    Kubota, T; Okamoto, Y

    2001-03-01

    Recently, noble metal catalysts are noted as promising candidates for new super-deep-hydrodesulfurization (HDS) catalysts. In this study, we investigated the structure of Pd particles supported on zeolite and Al2O3 under a sulfidation or reduction condition. From EXAFS analysis, it was found for sulfided Pd catalysts that small Pd sulfide clusters are formed without sintering. It was also revealed that no extensive growth of metal Pd particles occurs in Pd/NaY sulfide catalysts even after a treatment with H2 at 673 K. The dispersion of Pd metal particles is improved by H2/H2S treatment. These results indicate that in the presence of H2S, Pd shows high resistance against particle growth. A comparison of the Mo and Pd K-edge EXAFS spectra for MoS(x)/Pd-NaY and Pd-NaY catalysts revealed the existence of Mo-Pd bondings by the addition of Mo sulfide, indicating a direct interaction between Mo and Pd sulfides.

  3. Electroreduction of oxygen on Vulcan carbon supported Pd nanoparticles and Pd-M nanoalloys in acid and alkaline solutions

    Energy Technology Data Exchange (ETDEWEB)

    Alexeyeva, N. [Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu (Estonia); Sarapuu, A., E-mail: ave.sarapuu@ut.ee [Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu (Estonia); Tammeveski, K. [Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu (Estonia); Vidal-Iglesias, F.J.; Solla-Gullon, J.; Feliu, J.M. [Instituto de Electroquimica, Universidad de Alicante, Apartado 99, 03080 Alicante (Spain)

    2011-07-30

    Highlights: > Electroreduction of O{sub 2} on carbon-supported Pd, PdCo and PdFe nanoparticles is studied. > Pd-based catalysts were prepared by reduction in the presence of citrate and in microemulsion. > Four-electron reduction of O{sub 2} proceeds in both acid and alkaline media. > Specific activity of PdCo and PdFe nanocatalysts was similar to that of Pd nanoparticles. - Abstract: The kinetics of O{sub 2} reduction on novel electrocatalyst materials deposited on carbon substrates were studied using the rotating disk electrode (RDE) technique. Palladium nanoparticles and Pd-M (PdCo and PdFe) nanoalloys supported on Vulcan XC-72R were prepared using two different synthetic routes. The catalyst samples were examined by transmission electron microscopy (TEM) and the average size of metal nanoparticles was determined. Electrochemical measurements were performed in 0.5 M H{sub 2}SO{sub 4} and in 0.1 M NaOH solutions. The influence of different synthetic conditions on the values of specific activity and other kinetic parameters was investigated. These parameters were determined from the Tafel plots taking into account the real electroactive area for each electrode. Pd nanoparticles and Pd-M nanoalloys exhibit significantly high electrocatalytic activity for the four-electron reduction of oxygen to water.

  4. Bioceres: AG Biotechnology from Argentina

    Directory of Open Access Journals (Sweden)

    Roberto Feeney

    2016-04-01

    Full Text Available In this case we present a business decision-making situation in which the CEO of an Argentine Ag Biotech company, Bioceres, has to decide the best way to commercialize a new drought-tolerant transgenic technology. The company was founded by twenty three farmers, who shared a common dream that Argentina could become a benchmark in the development of Ag biotechnology. The case has strategic and financial implications, as well as decision-making situation involving a joint venture with an American biotechnology company. It also introduces to discussion the business models of Ag biotechnology companies in developing countries.

  5. {sup 105}Pd NQR study on NpPd{sub 5}Al{sub 2} and CePd{sub 5}Al{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Chudo, H; Sakai, H; Tokunaga, Y; Kambe, S; Haga, Y; Matsuda, T D; Yasuoka, H [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai-mura, Ibaraki, 319-1195 (Japan); Aoki, D; Homma, Y [Institute for Material Research, Tohoku University, Oarai, Ibaraki, 311-1313 (Japan); Nakano, Y; Honda, F; Settai, R [Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043 (Japan); Onuki, Y, E-mail: chudo.hiroyuki@jaea.go.j

    2010-01-15

    We report the results of {sup 105}Pd NQR experiments on NpPd{sub 5}Al{sub 2} and CePd{sub 5}Al{sub 2}. In the normal state at 6 K, the {sup 105}Pd NQR spectrum consists of four lines in both systems. These lines can be assigned to two sets of {+-}1/2 {r_reversible} {+-}3/2 and {+-}3/2 {r_reversible} {+-}5/2 NQR transitions arising from two crystallographically inequivalent Pd sites. From the analysis of the {sup 105}Pd NQR spectrum the nuclear quadrupole frequency {nu}{sub Q}, asymmetry parameter {eta} and electric field gradient V{sub zz} have been deduced.

  6. Incorporated Organic Modified Ag Nanoparticles in Ormocer

    Institute of Scientific and Technical Information of China (English)

    Haiping XIA; Jianli ZHANG; Jinhao WANG; Qiuhua NIE

    2004-01-01

    Ag nanoparticles coated trisodium citrate were incorporated in ormocer by sol-gel method. The doping concentration of Ag in ormocer is about 1.0% in weight. The HRTFM demonstrated that the particles disperse in ormocer, and the size of Ag nanoparticles is 5~10 nm. The absorption band of Ag nanoparticle at 410 nm was observed.

  7. File list: His.Dig.50.AllAg.AGS [Chip-atlas[Archive

    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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  19. THE CHALLENGE OF PD PATIENTS: GLUCOSE AND GLUCOSE DEGRADATION PRODUCTS IN PD SOLUTION

    Directory of Open Access Journals (Sweden)

    Yong-Lim Kim

    2012-06-01

    Full Text Available The main osmotic agent found in the peritoneal dialysis (PD solution is glucose. It has been of a wide use for great crystalloid osmotic power at a low concentration, simple metabolism, and excellent safety. On the other hand, anywhere between 60 to 80% of the glucose in the PD solution is absorbed - a 100 to 300 mg of daily glucose absorption. Once into the systemic circulation, glucose can be a cause for metabolic complications including obesity. Indeed, the diabetiform change observed in the peritoneal membrane in the long-term PD patients is believed attributable to the high-concentration glucose in the PD solution. The glucose absorbed from peritoneal cavity raises the risk of ‘glucose toxicity’, leading to insulin resistance and beta cell failure. Clinical similarity can be found in postprandial hyperglycemia, which is known to be associated with oxidative stress, endothelial dysfunction, NF-κb, and inflammation, affecting myocardial blood flow. Moreover, it is a proven independent risk factor of coronary artery disease in patients with type 2 diabetes, particularly of female gender. Though speculative yet, glucose toxicity might explain a higher mortality of PD patients after the first year compared with those on hemodialysis (more so in female, advanced-age patients with diabetes. Also included in the picture are glucose degradation products (GDPs generated along the course of heat sterilization or storage of the PD solution. They have been shown to induce apoptosis of peritoneal mesothelial cells, renal tubular epithelial cells, and endothelial cells, while spurring production of TGF-β and VEGF and facilitating epithelial mesenchymal transition. GDPs provide a stronger reactivity than glucose in the formation of AGEs, a known cause for microvascular complications and arteriosclerosis. Unfortunately, clinical studies using a low-GDP PD solution have provided mixed results on the residual renal function, peritonitis, peritoneal

  20. The PD1: PD-L1/2 pathway from discovery to clinical implementation

    Directory of Open Access Journals (Sweden)

    Kankana Bardhan

    2016-12-01

    Full Text Available The immune system has the difficult challenge of discerning and defending against a diversity of microbial pathogens, while simultaneously avoiding self-reactivity. T lymphocytes function as effectors and regulators of the immune system. While central tolerance mechanism results in deletion of the majority of self-reactive T lymphocytes during thymic selection, a fraction of self reactive lymphocytes escapes to the periphery and retains the potential to inflict destructive autoimmune pathology. The immune system evolved various mechanisms to restrain such auto-reactive T cells and maintain peripheral tolerance, including T cell anergy, deletion, and suppression by regulatory T cells (TRegs. These effects are regulated by a complex network of stimulatory and inhibitory receptors expressed on T cells and their ligands, which deliver cell-to-cell signals that dictate the outcome of T cell encountering with cognate antigens. Among the inhibitory immune mediators, the pathway consisting of the programmed cell death 1 (PD-1 receptor (CD279 and its ligands PD-L1 (B7-H1, CD274 and PD-L2 (B7-DC; CD273 plays a vital role in the induction and maintenance of peripheral tolerance and for the maintenance of T cell homeostasis. In contrast to its beneficial role in self-tolerance, the PD-1: PD-L1/L2 pathway mediates potent inhibitory signals that prevent the expansion and function of T effector cells and have detrimental effects on antiviral and antitumor immunity. Therapeutic targeting of this pathway has resulted in successful enhancement of T cell immunity against viral pathogens and tumors. Here, we will provide a brief overview on the properties of the components of the PD-1 pathway, the signaling events that are regulated by PD-1 triggering, and their consequences on the function of T effector cells.

  1. The PD1:PD-L1/2 Pathway from Discovery to Clinical Implementation

    Science.gov (United States)

    Bardhan, Kankana; Anagnostou, Theodora; Boussiotis, Vassiliki A.

    2016-01-01

    The immune system maintains a critically organized network to defend against foreign particles, while evading self-reactivity simultaneously. T lymphocytes function as effectors and play an important regulatory role to orchestrate the immune signals. Although central tolerance mechanism results in the removal of the most of the autoreactive T cells during thymic selection, a fraction of self-reactive lymphocytes escapes to the periphery and pose a threat to cause autoimmunity. The immune system evolved various mechanisms to constrain such autoreactive T cells and maintain peripheral tolerance, including T cell anergy, deletion, and suppression by regulatory T cells (TRegs). These effects are regulated by a complex network of stimulatory and inhibitory receptors expressed on T cells and their ligands, which deliver cell-to-cell signals that dictate the outcome of T cell encountering with cognate antigens. Among the inhibitory immune mediators, the pathway consisting of the programed cell death 1 (PD-1) receptor (CD279) and its ligands PD-L1 (B7-H1, CD274) and PD-L2 (B7-DC, CD273) plays an important role in the induction and maintenance of peripheral tolerance and for the maintenance of the stability and the integrity of T cells. However, the PD-1:PD-L1/L2 pathway also mediates potent inhibitory signals to hinder the proliferation and function of T effector cells and have inimical effects on antiviral and antitumor immunity. Therapeutic targeting of this pathway has resulted in successful enhancement of T cell immunity against viral pathogens and tumors. Here, we will provide a brief overview on the properties of the components of the PD-1 pathway, the signaling events regulated by PD-1 engagement, and their consequences on the function of T effector cells. PMID:28018338

  2. Effect of PD I Administration on Dopamine Receptors mRNAs Expression in the Lesioned Striatum of PD Rat Model

    Institute of Scientific and Technical Information of China (English)

    YANG Mei; SUN Shenggang; CAO Xuebing

    2005-01-01

    To study the effect of PD I administration on dopamine receptors (DR1, DR2 ) mRNAs expression in the lesioned striatum of the PD rat model and confirm if PD I has the effect of dopamine receptor agonist. The PD rats with unilateral 6-hydroxydopamine lesioned were administrated with PD I , L-dopa methyl/benserazide, L-dopa methyl/benserazide/ PD I , normal saline respectively for 4 weeks and their behavioral changes were observed. Then the rats were sacrificed and RT-PCR technique was used to detect changes of dopamine receptors (DR1, DR2 ) mRNAs expression in the ipsilateral striatum 1 day after the last treatment. The results showed that treatment with PD I plus L-dopa resulted in a stable contralateral rotation behavior; treatment with L-dopa resulted in a progressively increased contralateral rotation behavior. Rotation behavior induced by anhydromorphine decreased with PD I or PD I plus L-dopa treatment. Treatment With L-dopa or PD I plus L-dopa, up-regulation of DR1 mRNA and down regulation of DR2 mRNA were observed in the ipsilateral striatum which were more obvious than that treated with PD I or vehicle (P<0.05). It was concluded that long-term treatment with PD I could alleviate the behavior of PD rats.PD I had no apparent effect on the dopamine receptors (DR1 , DR2) mRNAs expression in the ipsilateral striatum and the PD I has no agonist effect on dopamine receptors.

  3. Aging assessment of large generator insulation based on PD measurements

    Institute of Scientific and Technical Information of China (English)

    YUE Bo; CHEN Xiaolin; CHENG Yonghong; XIE Hengkun

    2005-01-01

    The statistical parameters of phase resolved partial discharge (PD) distribution and ultra-wideband (UWB) characteristics of PD pulse are proposed for aging assessment of large generator insulation. Multi-stress aging tests of the model generator stator bar specimens were performed and PD measurements were conducted using both digital PD detector with frequency ranging from 40 kHz to 400 kHz and UWB PD detector with bandwidth from 10 MHz to 3 GHz at different aging stages. The test results show that the skewness and UWB frequency characteristics of PD can be taken as the characterization parameters for aging assessment of generator insulation. Furthermore, the measurement results of real generator stator bars show that these methods based on statistical parameters and UWB characteristics of PD are prospective for aging assessment and residual lifetime estimation of large generator stator insulation.

  4. Atomic Structure of Au−Pd Bimetallic Alloyed Nanoparticles

    KAUST Repository

    Ding, Yong

    2010-09-08

    Using a two-step seed-mediated growth method, we synthesized bimetallic nanoparticles (NPs) having a gold octahedron core and a palladium epitaxial shell with controlled Pd-shell thickness. The mismatch-release mechanism between the Au core and Pd shell of the NPs was systematically investigated by high-resolution transmission electron microscopy. In the NPs coated with a single atomic layer of Pd, the strain between the surface Pd layer and the Au core is released by Shockley partial dislocations (SPDs) accompanied by the formation of stacking faults. For NPs coated with more Pd (>2 nm), the stacking faults still exist, but no SPDs are found. This may be due to the diffusion of Au atoms into the Pd shell layers to eliminate the SPDs. At the same time, a long-range ordered L11 AuPd alloy phase has been identified in the interface area, supporting the assumption of the diffusion of Au into Pd to release the interface mismatch. With increasing numbers of Pd shell layers, the shape of the Au-Pd NP changes, step by step, from truncated-octahedral to cubic. After the bimetallic NPs were annealed at 523 K for 10 min, the SPDs at the surface of the NPs coated with a single atomic layer of Pd disappeared due to diffusion of the Au atoms into the surface layer, while the stacking faults and the L11 Au-Pd alloyed structure remained. When the annealing temperature was increased to 800 K, electron diffraction patterns and diffraction contrast images revealed that the NPs became a uniform Au-Pd alloy, and most of the stacking faults disappeared as a result of the annealing. Even so, some clues still support the existence of the L11 phase, which suggests that the L11 phase is a stable, long-range ordered structure in Au-Pd bimetallic NPs. © 2010 American Chemical Society.

  5. PD-1 blockade induces responses by inhibiting adaptive immune resistance

    Science.gov (United States)

    Tumeh, Paul C.; Harview, Christina L.; Yearley, Jennifer H.; Shintaku, I. Peter; Taylor, Emma J. M.; Robert, Lidia; Chmielowski, Bartosz; Spasic, Marko; Henry, Gina; Ciobanu, Voicu; West, Alisha N.; Carmona, Manuel; Kivork, Christine; Seja, Elizabeth; Cherry, Grace; Gutierrez, Antonio; Grogan, Tristan R.; Mateus, Christine; Tomasic, Gorana; Glaspy, John A.; Emerson, Ryan O.; Robins, Harlan; Pierce, Robert H.; Elashoff, David A.; Robert, Caroline; Ribas, Antoni

    2014-01-01

    Therapies that target the programmed death-1 (PD-1) receptor have shown unprecedented rates of durable clinical responses in patients with various cancer types.1–5 One mechanism by which cancer tissues limit the host immune response is via upregulation of PD-1 ligand (PD-L1) and its ligation to PD-1 on antigen-specific CD8 T-cells (termed adaptive immune resistance).6,7 Here we show that pre-existing CD8 T-cells distinctly located at the invasive tumour margin are associated with expression of the PD-1/PD-L1 immune inhibitory axis and may predict response to therapy. We analyzed samples from 46 patients with metastatic melanoma obtained before and during anti-PD1 therapy (pembrolizumab) using quantitative immunohistochemistry, quantitative multiplex immunofluorescence, and next generation sequencing for T-cell receptors (TCR). In serially sampled tumours, responding patients showed proliferation of intratumoural CD8+ T-cells that directly correlated with radiographic reduction in tumour size. Pre-treatment samples obtained from responding patients showed higher numbers of CD8, PD1, and PD-L1 expressing cells at the invasive tumour margin and inside tumours, with close proximity between PD-1 and PD-L1, and a more clonal TCR repertoire. Using multivariate analysis, we established a predictive model based on CD8 expression at the invasive margin and validated the model in an independent cohort of 15 patients. Our findings indicate that tumour regression following therapeutic PD-1 blockade requires pre-existing CD8+ T cells that are negatively regulated by PD-1/PD-L1 mediated adaptive immune resistance. PMID:25428505

  6. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>AgEcon Search is a free,open access repository of full-text scholarly literature in agricultural and applied economics,including working papers,conference papers,and journal articles.AgEcon Search is co-sponsored by the Department of Applied Economics and the University Libraries at University of Minnesota and the Agricultural and Applied Economics Association.Research in Agricultural

  7. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>AgEcon Search is a free,open access repository of full-text scholarly literature in agricultural and applied economics,including working papers,conference papers,and journal articles. AgEcon Search is co-sponsored by the Department of Applied Economics and the University Libraries at University of Minnesota and the Agricultural and Applied Economics Association. Research in Agricultural

  8. Hydrogenation of chalcones using hydrogen permeating through a Pd and palladized Pd electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, M., E-mail: mcgutier@unse.edu.a [INQUINOA - CONICET, Instituto de Ciencias Quimicas, Facultad de Agronomia Agroindustrias, Universidad Nacional de Santiago del Estero, Avda, Belgrano (S) 1912, 4200, Santiago del Estero (Argentina); Nazareno, M.A. [INQUINOA - CONICET, Instituto de Ciencias Quimicas, Facultad de Agronomia Agroindustrias, Universidad Nacional de Santiago del Estero, Avda, Belgrano (S) 1912, 4200, Santiago del Estero (Argentina); Sosa, V. [Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Agencia postal 4, Casilla 61, 5000, Cordoba (Argentina); Lopez de Mishima, B.A., E-mail: bmishima@unse.edu.a [INQUINOA - CONICET, Instituto de Ciencias Quimicas, Facultad de Agronomia Agroindustrias, Universidad Nacional de Santiago del Estero, Avda, Belgrano (S) 1912, 4200, Santiago del Estero (Argentina); Mishima, H.T. [INQUINOA - CONICET, Instituto de Ciencias Quimicas, Facultad de Agronomia Agroindustrias, Universidad Nacional de Santiago del Estero, Avda, Belgrano (S) 1912, 4200, Santiago del Estero (Argentina)

    2010-08-01

    The hydrogenation of benzalacetone and benzalacetophenone was carried out using atomic hydrogen permeating through a palladium membrane. A two-compartment cell separated by a Pd sheet or a palladized Pd (Pd/Pd black) sheet electrode was employed. The reduction products were identified by (GC) gas chromatography, UV-vis absorption spectroscopy and NMR spectroscopy. The carbon-carbon double bond was hydrogenated and the benzylacetone and benzylacetophenone were obtained as products using palladium catalyst. The current efficiency for hydrogenation reaction increases when the current density for water electrolysis decreases and depends on the initial chalcone concentration. It is over 90% at the concentration of 10 mmol L{sup -1}. The hydrogen absorption and diffusion into and through a palladium membrane electrode has been studied by using an electrochemical impedance spectroscopy method. The impedance results would indicate that the hydrogen permeated through the membrane is consumed by the chalcone during the hydrogenation process keeping as the permeable boundary condition in the outer side of the Pd membrane the hydrogen activity almost zero. The hydrogen entering the metal through an adsorbed state and the rate of hydrogen absorption is diffusion-controlled.

  9. Corrosion behavior of Pd-Cu and Pd-Co alloys in synthetic saliva.

    Science.gov (United States)

    Goehlich, V; Marek, M

    1990-04-01

    Pd-based alloys are major alternatives to gold-based alloys for PFM applications. In electrolytes simulating oral fluids, these alloys exhibit electrode behavior similar to passivity of active metals, i.e., a potential region of almost constant current density up to a critical potential, above which the current increases. The objective of this study was to correlate the electrode behavior with the results of solution analyses and changes in the surface composition of the alloys. Binary alloys Pd-15 wt% Cu and Pd-19 wt% Co, as well as the pure components, were examined. Corrosion potentials vs. time, potentiodynamic anodic polarization curves, polarization resistances vs. time, and potentiostatic anodic charges were measured with synthetic saliva used as the electrolyte. The concentrations of Pd, Cu, and Co in the solution after various exposures were determined by atomic absorption. The surfaces of the alloys were examined by x-ray photoelectron spectroscopy before and after the exposures. The results show that selective dissolution of the less-noble components occurred on the surfaces of both alloys for all the exposures, leaving the surfaces highly enriched in Pd. This enrichment contributed to the potential changes and the passive-type behavior. Copper dissolved more than cobalt at longer exposures and higher potentials, in spite of its higher nobility. Dissolution of cobalt seemed to be limited by the formation of a surface film, which may be related to the transition character of this element.

  10. Microstructural and chemical transformation of thin Ti/Pd and TiDy/Pd bilayer films induced by vacuum annealing.

    Science.gov (United States)

    Lisowski, W; Keim, E G; Kaszkur, Z; van den Berg, A H J; Smithers, M A

    2007-11-01

    Using a combination of scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction and X-ray photoelectron spectroscopy (XPS), we made a comparative study of the high-temperature annealing impact on thin titanium deuteride (TiD(y)) films covered by an ultrathin Pd layer, and on Ti/Pd bilayer films. The bilayer films were prepared under ultrahigh vacuum conditions and were in situ annealed using the same annealing procedure. It was found that the surface and the bulk morphology of both films undergo different annealing-induced transformations, leading to an extensive intermixing between the Ti and Pd layers and the formation of a new PdTi(2) bimetallic phase. Energy-filtered TEM imaging and energy-dispersive X-ray spectrometry analysis, as well as XPS depth profiling all provided evidence of a different distribution of Pd and Ti in the annealed TiD(y)/Pd film compared with the annealed Ti/Pd film. Our results show that thermal decomposition of TiD(y), as a consequence of annealing the TiD(y)/Pd film, modifies the intermixing process, thereby promoting Ti diffusion into the Pd-rich top layer of the TiD(y) film and thus providing a more likely path for the formation of the PdTi(2) phase than in an annealed Ti/Pd film.

  11. Blocking of the PD-1/PD-L1 Interaction by a D-Peptide Antagonist for Cancer Immunotherapy.

    Science.gov (United States)

    Chang, Hao-Nan; Liu, Bei-Yuan; Qi, Yun-Kun; Zhou, Yang; Chen, Yan-Ping; Pan, Kai-Mai; Li, Wen-Wen; Zhou, Xiu-Man; Ma, Wei-Wei; Fu, Cai-Yun; Qi, Yuan-Ming; Liu, Lei; Gao, Yan-Feng

    2015-09-28

    Blockade of the protein-protein interaction between the transmembrane protein programmed cell death protein 1 (PD-1) and its ligand PD-L1 has emerged as a promising immunotherapy for treating cancers. Using the technology of mirror-image phage display, we developed the first hydrolysis-resistant D-peptide antagonists to target the PD-1/PD-L1 pathway. The optimized compound (D) PPA-1 could bind PD-L1 at an affinity of 0.51 μM in vitro. A blockade assay at the cellular level and tumor-bearing mice experiments indicated that (D) PPA-1 could also effectively disrupt the PD-1/PD-L1 interaction in vivo. Thus D-peptide antagonists may provide novel low-molecular-weight drug candidates for cancer immunotherapy.

  12. Facile synthesis, structure, and properties of Ag2S/Ag heteronanostructure

    Science.gov (United States)

    Sadovnikov, S. I.; Gusev, A. I.

    2016-09-01

    Ag2S/Ag heteronanostructure has been produced by a simple one-stage chemical deposition from aqueous solutions of silver nitrate, sodium sulfide, and sodium citrate with the use of monochromatic light irradiation. For simultaneous synthesis of Ag2S and Ag nanoparticles, deposition has been performed from reaction mixtures with reduced sodium sulfide concentration. The size of Ag2S and Ag nanoparticles is 45-50 and 15-20 nm, respectively. It is established that in the contact layer between silver sulfide and silver, nonconducting α-Ag2S acanthite transforms into superionic β-Ag2S argentite under the action of external electric field. The scheme of the operation of a resistive switch based on an Ag2S/Ag heteronanostructure is proposed. The UV-Vis optical absorption spectra of colloidal solutions of Ag2S/Ag heteronanostructures have been studied.

  13. Usefulness of Genetic Testing in PD and PD Trials: A Balanced Review.

    Science.gov (United States)

    Gasser, Thomas

    2015-01-01

    An increasing proportion of the individual and population risk to develop Parkinson's disease (PD) can be explained by genetic variants of different effect strength, forming a continuum from rare high penetrance gain or loss of function mutations to relatively common genetic risk variants that only mildly modify disease risk. In the coming years, further advances in molecular genetic technologies, in particular the increasing use of next generation sequencing, is likely to generate a wealth of new knowledge about the genetic basis of PD. Although specific treatments for PD based on the underlying genetic etiology will probably not be available in the near future, genetic testing is therefore likely to play an increasing role, both in the counselling of individual patients and their families with respect to the expected disease course and recurrence risks, and in the stratification of patient groups in clinical trials. Thus, the usefulness of genetic testing strongly depends on question asked and needs to be considered within each particular setting.

  14. Immunotherapy: Beyond Anti-PD-1 and Anti-PD-L1 Therapies.

    Science.gov (United States)

    Antonia, Scott J; Vansteenkiste, Johan F; Moon, Edmund

    2016-01-01

    Advanced-stage non-small cell lung cancer (NSCLC) and small cell lung cancer are cancers in which chemotherapy produces a survival benefit, although it is small. We now know that anti-PD-1/PD-L1 has substantial clinical activity in both of these diseases, with an overall response rate (ORR) of 15%-20%. These responses are frequently rapid and durable, increase median overall survival (OS) compared with chemotherapy, and produce long-term survivors. Despite these very significant results, many patients do not benefit from anti-PD-1/PD-L1. This is because of the potential for malignancies to co-opt myriad immunosuppressive mechanisms other than aberrant expression of PD-L1. Conceptually, these can be divided into three categories. First, for some patients there is likely a failure to generate sufficient functional tumor antigen-specific T cells. Second, for others, tumor antigen-specific T cells may be generated but fail to enter into the tumor parenchyma. Finally, there are a large number of immunosuppressive mechanisms that have the potential to be operational within the tumor microenvironment: surface membrane immune checkpoint proteins PD-1, CTLA-4, LAG3, TIM3, BTLA, and adenosine A2AR; soluble factors and metabolic alterations interleukin (IL)-10, transforming growth factor (TGF)-β, adenosine, IDO, and arginase; and inhibitory cells, cancer-associated fibroblasts (CAFs), regulatory T cells, myeloid-derived suppressor cells (MDSCs), and tumor-associated macrophages. In this article, we discuss three strategies to generate more tumor-reactive T cells for patients: anti-CTLA-4, therapeutic tumor vaccination, and adoptive cellular therapy, with T cells redirected to tumor antigens using T-cell receptor (TCR) or chimeric antigen receptor (CAR) gene modification. We also review some of the various strategies in development to thwart tumor microenvironment immunosuppressive mechanisms. Strategies to drive more T cells into tumors remain a significant challenge.

  15. Interfacial processes in the Pd/a-Ge:H system

    Science.gov (United States)

    Edelman, F.; Cytermann, C.; Brener, R.; Eizenberg, M.; Weil, R.; Beyer, W.

    1993-06-01

    The kinetics of phase transformation has been studied in a two-layer structure of Pd/a-Ge:H after vacuum annealing at temperatures from 180 to 500°C. The a-Ge:H was deposited at 250°C on both c-Si and cleaved NaCl substrates in an RF glow discharge from a GeH 4/H 2 mixture. It was found that, similarly to the Pd/c-Ge and the Pd/a-Ge (e-gun deposited) systems, in the case of 0.15-0.2 μm Pd/0.6-1.0 μm a-Ge:H interfacial germanides formed first through the production of Pd 2Ge (plus a small amount of PdGe), and then PdGe was produced. The growth of both compounds was found to be diffusion-controlled. The nonreacted a-Ge:H layer beneath the germanide overlayer crystallized at 400-500°C. A reverse sequence of germanides formation was revealed in the case of 50 nm Pd/30 nm a-Ge:H, studied by in situ heat treatment in the TEM utilizing non-supported samples. The first germanide detected was PdGe and then, as a result of PdGe and Ge reaction or the PdGe decomposition, Pd 2Ge formed. The temperature dependence of the incubation time before the first ˜ 10 nm PdGe grains formed, followed an Arrhenius curve with an activation energy of 1.45 eV.

  16. Induction of PD-L1 expression by epidermal growth factor receptor–mediated signaling in esophageal squamous cell carcinoma

    Directory of Open Access Journals (Sweden)

    Zhang W

    2017-02-01

    Full Text Available Wencheng Zhang,1 Qingsong Pang,1 Cihui Yan,2 Qifeng Wang,3 Jingsong Yang,3 Shufei Yu,3 Xiao Liu,3 Zhiyong Yuan,1 Ping Wang,1 Zefen Xiao3 1Department of Radiation Oncology, 2Department of Immunology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, People’s Republic of China; 3Department of Radiation Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China Purpose: The purpose of this study was to investigate the potential effect of activation of epidermal growth factor receptor (EGFR signaling pathway on the expression of programmed death-ligand 1 (PD-L1 in esophageal squamous cell carcinoma (ESCC cells with EGFR overexpression. Methods: Flow cytometry and Western blot methods were used to assess PD-L1 expression on ESCC cells when EGFR signaling pathway was activated by epidermal growth factor (EGF with or without EGFR-specific inhibitor AG-1478, and then EGFR signaling array was applied to analyze the potential signaling pathways involved. Results: This study found that PD-L1 expression increased significantly in an EGFR-dependent manner by the activation of EGFR signaling and decreased sharply when EGFR signaling was blocked. The upregulated expression of PD-L1 was not associated with EGFR-STAT3 signaling pathway, but may be affected by EGFR–PI3K–AKT, EGFR–Ras–Raf–Erk, and EGR–PLC-γ signaling pathways. Conclusion: The expression of PD-L1 can be regulated by EGFR signaling activation in ESCC, which indicates an important role for EGFR-mediated immune escape and potential molecular pathways for EGFR-targeted therapy and immunotherapy. Keywords: epidermal growth factor receptor, programmed death-ligand 1, esophageal squamous cell carcinoma, immune checkpoint

  17. Atomic layer deposition on Pd nanocrystals for forming Pd-TiO2 interface toward enhanced CO oxidation

    Directory of Open Access Journals (Sweden)

    Yu Bai

    2016-06-01

    Full Text Available Pd typically exhibits relatively low catalytic activity in CO oxidation, as CO is apt to be adsorbed on Pd to poison the surface for O2 activation. In this Letter, we report that this limitation can be overcome by integrating Pd with TiO2. The TiO2 was coated on Pd nanocubes with a controllable thickness using atomic layer deposition (ALD method. Given the different work functions of TiO2 and Pd, the electrons in TiO2 semiconductor will flow toward Pd. With the electron density increased on Pd, the adsorption of CO to Pd will be weakened while the oxygen activation can be facilitated. Meanwhile, the interface-confined sites at Pd-TiO2 may further enhance the oxygen activation. As the species adsorption and activation are strongly correlated with electron density, the performance of Pd-TiO2 in CO oxidation turns out to depend on the TiO2 thickness, which determines the number of transferred electrons, within a certain range (<1.8 nm. This work provides a new strategy for enhancing catalytic performance through tailoring charge densities in hybrid catalysts.

  18. Atomic layer deposition on Pd nanocrystals for forming Pd-TiO2 interface toward enhanced CO oxidation

    Institute of Scientific and Technical Information of China (English)

    Yu Bai; Chunlei Wang; Xingyi Zhou; Junling Lu; Yujie Xiong

    2016-01-01

    Pd typically exhibits relatively low catalytic activity in CO oxidation, as CO is apt to be adsorbed on Pd to poison the surface for O2 activation. In this Letter, we report that this limitation can be overcome by integrating Pd with TiO2. The TiO2 was coated on Pd nanocubes with a controllable thickness using atomic layer deposition (ALD) method. Given the different work functions of TiO2 and Pd, the electrons in TiO2 semiconductor will flow toward Pd. With the electron density increased on Pd, the adsorption of CO to Pd will be weakened while the oxygen activation can be facilitated. Meanwhile, the interface-confined sites at Pd-TiO2 may further enhance the oxygen activation. As the species adsorption and activation are strongly correlated with electron density, the performance of Pd-TiO2 in CO oxidation turns out to de-pend on the TiO2 thickness, which determines the number of transferred electrons, within a certain range ( o 1.8 nm). This work provides a new strategy for enhancing catalytic performance through tai-loring charge densities in hybrid catalysts.

  19. Genetic polymorphisms of immune checkpoint proteins PD-1 and TIM-3 are associated with survival of patients with hepatitis B virus-related hepatocellular carcinoma

    Science.gov (United States)

    Li, Zhu; Li, Na; Li, Fang; Zhou, Zhihua; Sang, Jiao; Jin, Zhao; Liu, Huihui; Han, Qunying; Lv, Yi; Liu, Zhengwen

    2016-01-01

    Programmed cell death protein 1 (PD-1) and T-cell immunoglobulin domain and mucin domain containing molecule 3 (TIM-3) are involved in hepatitis B virus (HBV) infection and hepatocellular carcinoma (HCC). This study examined the associations of PD1 and TIM3 polymorphisms with the overall survival (OS) of a prospective cohort of 258 HBV-related HCC patients. Results showed that PD1 +8669 G allele-containing genotypes or TIM3 −1516 genotype GG were significantly associated with longer OS (P < 0.001 and P = 0.001, respectively). In multivariate analysis, PD1 +8669 G allele-containing genotypes and TIM3 −1516 genotype GG were independently associated with longer OS (hazard ratio (HR), 1.835; 95% confidence interval (CI), 1.342–2.509; P < 0.001 and HR, 2.070; 95%CI, 1.428–3.002; P < 0.001, respectively). PD1 +8669 G allele-containing genotypes were significantly associated with longer OS in patients receiving surgical (resection or radiofrequency) treatment, transcatheter arterial chemoembolization (TACE) or supportive and symptomatic treatment. TIM3 −1516 genotype GG was significantly associated with longer OS in TACE patients. In multivariate analysis, PD1 +8669 G allele-containing genotypes were independently associated with longer OS in each treatment population. TIM3 −1516 genotype GG was independently associated with longer OS in patients receiving surgical treatment or TACE. These findings suggest that PD1 +8669 A/G and TIM3 −1516 G/T polymorphisms may affect the prognosis of HBV-related HCC and may be new predictors of prognosis for HCC patients. PMID:27034168

  20. Ruhrgas AG. Business report 2000; Ruhrgas AG. Geschaeftsbericht 2000

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    A detailed account of the situation of the international gas market provides the basis of the status report of Ruhrgas AG and the group of affiliated companies. Emphasis is placed on gas procurement aspects, sales volumes, the construction and operation of natural gas distribution systems, and on development, utilization and application aspects. The activities and situation of major Ruhrgas AG holding companies are described, and the annual financial statements are documented. (orig.) [German] Ausgehend von einer eingehenden Beschreibung des internationalen Gasmarktes wird ein Lagebericht des Konzerns sowie der Ruhrgas AG gegeben. Dabei wird insbesondere auf Fragen der Gasbeschaffung, des Gasabsatzes, des Baus und Betriebs von Erdgasverteilungsnetzen, sowie der Entwicklung und der Anwendungstechnik eingegangen. Ferner wird ueber den Geschaeftsverlauf wesentlicher Ruhrgas-Beteiligungsgesellschaften berichtet. Abschliessend wird der Jahresabschluss dokumentiert. (orig.)

  1. Influence of Pd-precursor on the acetoxylation activity of Pd-Sb/TiO{sub 2} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ben-homeid, A. [Benghazi Univ. (Libyan Arab Jamahiriya). Chemistry Dept.; Kalevaru, V.N.; Radnik, J.; Luecke, B.; Martin, A. [Leibniz-Institut fuer Katalyse e.V. an der Universitaet Rostock (Germany)

    2013-11-01

    The impact of palladium precursors (e.g. chloride-PdCl{sub 2}; acetate-Pd(OAc){sub 2}; nitrate-Pd(NO{sub 3}){sub 2}) on the catalytic properties of Pd-Sb/TiO{sub 2} catalysts used for acetoxylation of toluene has been investigated. The catalysts were characterized by different techniques such as N{sub 2}-adsorption (BET-surface area and pore volume), XRD, TEM, CO-Chemisorption and XPS for better understanding of the catalytic properties of the catalysts. The acetate and nitrate-type precursors exhibited higher surface areas, pore volumes and higher dispersion of Pd, but displayed poor performance compared to chloride precursor. TEM analysis indicated that the size of Pd particles depended upon the nature of Pd-precursor. Among the three, chloride precursor exhibited bigger Pd particles. XPS results revealed that all the fresh catalysts irrespective of Pd-precursor contained Pd in oxidized state (i.e. Pd{sup +2}), while in the spent catalysts such oxidized Pd species were reduced. The catalytic performance was found to depend strongly on the nature of precursor used. Among the three, the catalysts prepared from chloride-type precursor showed much higher overall catalytic activity (68%) than those of nitrate and/or acetate type precursors. Moreover, these two precursors (acetate and nitrate) gave higher total oxidation products due to oxidative decomposition of mainly acetic acid. Furthermore, the catalyst prepared from Cl-precursor revealed easy deactivation due to coke deposition and also due to loss of Pd in the near-surface-region. (orig.)

  2. PD-1/PD-L1 signal pathway participates in HCV F protein-induced T cell dysfunction in chronic HCV infection.

    Science.gov (United States)

    Xiao, Wen; Jiang, Long Feng; Deng, Xiao Zhao; Zhu, Dan Yan; Pei, Jia Ping; Xu, Mao Lei; Li, Bing Jun; Wang, Chang Jun; Zhang, Jing Hai; Zhang, Qi; Zhou, Zhen Xian; Ding, Wei Liang; Xu, Xiao Dong; Yue, Ming

    2016-04-01

    Programmed cell death-1/programmed cell death-1 ligand 1 (PD-1/PD-L1) inhibitory signal pathway has been verified to be involved in the establishment of persistent viral infections. Blockade of PD-1/PD-L1 engagement to reinvigorate T cell activity is supposed to be a potential therapeutic scheme. Studies have verified the participation of PD-1/PD-L1 in hepatitis C virus (HCV) core protein-regulated immune response. To determine the roles of PD-1/PD-L1 signal pathway in HCV F protein-induced immunoreaction in chronic HCV infection, variations in T cells were examined. The results showed that PD-1 expression on CD8(+) and CD4(+) T cells was increased with HCV F stimulation in both chronic HCV patients and healthy controls, and could be reduced partly by PD-1/PD-L1 blocking. Additionally, by PD-1/PD-L1 blocking, HCV F-induced inhibition of T cell proliferation and promotion of cellular apoptosis were partly or even totally recovered. Furthermore, levels of both Th1 and Th2 cytokines were elevated in the presence of anti-PD-L1 antibody. All these results indicated that PD-1/PD-L1 signal pathway also participates in HCV F protein-induced immunoregulation. PD-1/PD-L1 blocking plays important roles in the restoration of effective functionality of the impaired T cells in chronic HCV patients.

  3. Functional Ag porous films prepared by electrospinning

    Science.gov (United States)

    Dong, Guoping; Xiao, Xiudi; Liu, Xiaofeng; Qian, Bin; Liao, Yang; Wang, Chen; Chen, Danping; Qiu, Jianrong

    2009-06-01

    Face-centered cubic Ag porous films have been prepared directly from the heat treatment of AgNO 3-doped poly(vinyl alcohol) (PVA) electrospun nanofibers. Using Rhodamine B (RB) as the probing molecule, the surface-enhanced Raman scattering (SERS) effect of Ag porous films was demonstrated. The antibacterial activity of Ag porous films was also studied in this work. The propagation and biological activity of yeast cells were effectively inhibited by Ag porous films. These functional Ag porous films were expected to be applied in many fields, such as catalysis, diagnostics, sensors and antibacterial, etc.

  4. Movements in Parties: OccupyPD

    Directory of Open Access Journals (Sweden)

    Donatella della Porta

    2015-03-01

    Full Text Available When the United States activists called for people to Occupy#everywhere, it is unlikely they were thinking of the headquarters of the Italian centre-left party. Parties and movements are often considered to be worlds apart. In reality, parties have been relevant players in movement politics, and movements have influenced parties, often through the double militancy of many of their members. OccupyPD testifies to a continuous fluidity at the movement-party border, but also to a blockage in the party’s interactions with society that started long before the economic crisis but drastically accelerated with it. In this paper we present the OccupyPD Movement as a case of interaction between party politics and social movement politics, and in particular between the base membership of a centre-left party and the broader anti-austerity movement that diffused from the US to Europe adopting similar forms of actions and claims. Second, by locating it within the context of the economic and democratic crisis that erupted in 2007, we understand its emergence as a reaction towards politics in times of crisis of responsibility, by which we mean a drastic drop in the capacity of the government to respond to citizens’ requests. To fulfil this double aim, we bridge social movement studies with research on party change, institutional trust and democratic theory, looking at some political effects of the economic crisis in terms of a specific form of legitimacy crisis, as well as citizens’ responses to it, with a particular focus on the political meaning of recent anti-austerity protests. In this analysis, we refer to both quantitative and qualitative data from secondary liter-ature and original in-depth interviews carried out with a sample of OccupyPD activists.

  5. PD-1/PD-L1抑制途径与自身免疫性糖尿病%PD-1/PD-L1 inhibitory pathway and autoimmune diabetes

    Institute of Scientific and Technical Information of China (English)

    杜宣; 施毕旻

    2011-01-01

    Programmed death-1 (PD-1,CD279),a member of CD28 superfamily,is inducibly expressed on activated T cells, B cells and natural killer T cells. PD-1 has two ligands: PD-L1 (B7-H1,CD274) and PD-L2 (B7-DC, CD273). The interaction between PD-1 and PD-L1 can provide autoreactive T cells with negative signals so as to inhibit the persistent immune reaction to self-antigens. Deficiency or blockade of PD-1/PD-L1 inhibitory pathway may initiate excessive proliferation and activation of autoreactive T cells. This can lead to immunological injury of autologous tissue and further result in various clinical manifestations of autoimmune disease in the host. It has been noticed that PD-1/PD-L1 inhibitory pathway is involved in the occurrence and development of autoimmune diabetes. Islet-specific autoreactive T cells could be activated continuously and cause pancreatic tissue injury when the negative inhibitory signal of PD-1/PD-L1 pathway was blocked by the special monoclonal antibodies. This may impair the function of pancreatic β cells in insulin secretion and cause the abnormality in glucose metabolism and regulation in diabetic host.%PD-1(CD279)是一种负性协同刺激分子,属于CD28超家族成员,呈诱导性表达于活化的T、B和自然杀伤细胞表面.PD-L1(B7-H1,CD274)和PD-L2(B7-DC,CD273)是PD-1的两个配体.PD-1和PD-L1相互作用可以使活化的自身反应性T细胞获得负性信号,抑制其对自身抗原持续的免疫应答.若PD-1/PD-L1抑制途径缺失或被阻断,则导致自身反应性T细胞过度激活及增殖并引起自身组织的免疫损伤,进而引发多种自身免疫性疾病的临床表现.业已证明,自身免疫性糖尿病的发生、发展与PD-1/PD-LI抑制途径密切相关.阻断PD-1/PD-L1抑制途径,持续活化的胰岛自身反应性T细胞将损伤胰岛组织,致使胰岛β细胞分泌胰岛素功能受损,引起外周血糖显著升高,从面产生一系列病理变化.

  6. Effect of Ag Templates on the Formation of Au-Ag Hollow/Core-Shell Nanostructures.

    Science.gov (United States)

    Tsai, Chi-Hang; Chen, Shih-Yun; Song, Jenn-Ming; Haruta, Mitsutaka; Kurata, Hiroki

    2015-12-01

    Au-Ag alloy nanostructures with various shapes were synthesized using a successive reduction method in this study. By means of galvanic replacement, twined Ag nanoparticles (NPs) and single-crystalline Ag nanowires (NWs) were adopted as templates, respectively, and alloyed with the same amount of Au(+) ions. High angle annular dark field-scanning TEM (HAADF-STEM) images observed from different rotation angles confirm that Ag NPs turned into AuAg alloy rings with an Au/Ag ratio of 1. The shifts of surface plasmon resonance and chemical composition reveal the evolution of the alloy ring formation. On the other hand, single-crystalline Ag NWs became Ag@AuAg core-shell wires instead of hollow nanostructure through a process of galvanic replacement. It is proposed that in addition to the ratio of Ag templates and Au ion additives, the twin boundaries of the Ag templates were the dominating factor causing hollow alloy nanostructures.

  7. Breaking of Cooper pairs in 108Pd

    Science.gov (United States)

    Rahmatinejad, A.; Kakavand, T.; Razavi, R.

    2016-04-01

    In this paper, breaking of Cooper pairs in 108Pd is investigated within the canonical ensemble framework and the BCS model. Our results show an evidence of two phase transitions, which are related to neutron and proton systems. Also, with consideration of pairing interaction, the role of neutron and proton systems in entropy, spin cutoff parameter and as a result in the moment of inertia are investigated. The results show minor role for the proton system at low temperatures and approximately equal roles for both neutron and proton systems after the critical temperature. Good agreement was observed between obtained results and the experimental data.

  8. Synthesis and alignment of silver nanorods and nanowires and the formation of Pt, Pd, and core/shell structures by galvanic exchange directly on surfaces.

    Science.gov (United States)

    Sławiński, Grzegorz W; Zamborini, Francis P

    2007-09-25

    Here we describe the synthesis of Ag nanorods (NRs) (aspect ratio or =20) directly on surfaces by seed-mediated growth. The procedure involves attaching gold seed nanoparticles (Au NPs) to 3-mercaptopropyltrimethoxysilane (MPTMS)-functionalized silicon or glass surfaces and growing them into NRs/NWs by placing the substrates into a solution containing cetyltrimethylammonium bromide (CTAB), silver nitrate, and ascorbic acid with the pH ranging from 7 to 12. Under our conditions, Ag NRs/NWs grow optimally at pH 10.6 with a 3% yield, where spherical, triangular, and hexagonal nanostructures represent the other byproducts. The length of Ag NRs/NWs ranges from 50 nm to more than 10 microm, the aspect ratio (AR) ranges from 1.4 to >300, and the average diameter is approximately 35 nm. Approximately 40% of the 1D structures are NRs, and 60% are NWs as defined by their ARs. We also report the alignment of Ag NRs/NWs directly on surfaces by growing the structures on amine-functionalized Si(100) surfaces after an amidation reaction with acetic acid and a method to improve the percentage of Ag NRs/NWs on the surface by removing structures of other shapes with adhesive tape. Surface-grown Ag NRs/NWs also react with salts of palladium, platinum, and gold via galvanic exchange reactions to form high-surface-area 1D structures of the corresponding metal. The combination of the seed-mediated growth of Ag on Au NRs followed by the galvanic exchange of Ag with Pd leads to interesting core/shell NRs grown directly on surfaces. We used scanning electron microscopy, UV-vis spectroscopy, and X-ray photoelectron spectroscopy to characterize the surface-grown nanostructures.

  9. Synthesis, morphological control, and antibacterial properties of hollow/solid Ag2S/Ag heterodimers

    KAUST Repository

    Pang, Maolin

    2010-08-11

    Ag2S and Ag are important functional materials that have received considerable research interest in recent years. In this work, we develop a solution-based synthetic method to combine these two materials into hollow/solid Ag2S/Ag heterodimers at room temperature. Starting from monodisperse Cu2O solid spheres, CuS hollow spheres can be converted from Cu2O through a modified Kirkendall process, and the obtained CuS can then be used as a solid precursor for preparation of the Ag2S/Ag heterodimers through ion exchange and photo-assisted reduction. We have found that formation of the Ag2S/Ag heterodimers is instantaneous, and the size of Ag nanocrystals on the hollow spheres of Ag2S can be controlled by changing the concentration and power of reducing agents in the synthesis. The growth of Ag nanoparticles on hollow spheres of Ag2S in the dimers is along the [111] direction of the silver crystal; the light absorption properties have also been investigated. Furthermore, coupling or tripling of Ag2S/Ag heterodimers into dumbbell-like trimers ((Ag 2S)2/Ag, linear) and triangular tetramers ((Ag 2S)3/Ag, coplanar) can also be attained at 60°C by adding the bidentate ligand ethylenediamine as a cross-linking agent. To test the applicability of this highly asymmetric dipolar composite, photocatalytic inactivation of Escherichia coli K-12 in the presence of the as-prepared Ag 2S/Ag heterodimers has been carried out under UV irradiation. The added Ag2S/Ag heterodimers show good chemical stability under prolonged UV irradiation, and no appreciable solid dissolution is found. Possible mechanisms regarding the enhanced antibacterial activity have also been addressed. © 2010 American Chemical Society.

  10. `Pd20Sn13' revisited: crystal structure of Pd6.69Sn4.31

    Directory of Open Access Journals (Sweden)

    Wilhelm Klein

    2015-07-01

    Full Text Available The crystal structure of the title compound was previously reported with composition `Pd20Sn13' [Sarah et al. (1981. Z. Metallkd, 72, 517–520]. For the original structure model, as determined from powder X-ray data, atomic coordinates from the isostructural compound Ni13Ga3Ge6 were transferred. The present structure determination, resulting in a composition Pd6.69Sn4.31, is based on single crystal X-ray data and includes anisotropic displacement parameters for all atoms as well as standard uncertainties for the atomic coordinates, leading to higher precision and accuracy for the structure model. Single crystals of the title compound were obtained via a solid-state reaction route, starting from the elements. The crystal structure can be derived from the AlB2 type of structure after removing one eighth of the atoms at the boron positions and shifting adjacent atoms in the same layer in the direction of the voids. One atomic site is partially occupied by both elements with a Pd:Sn ratio of 0.38 (3:0.62 (3. One Sn and three Pd atoms are located on special positions with site symmetry 2. (Wyckoff letter 3a and 3b.

  11. Low-energy electron diffraction investigation of epitaxial growth: Pt and Pd on Pd(100)

    Energy Technology Data Exchange (ETDEWEB)

    Flynn-Sanders, D.

    1990-09-21

    We investigate the epitaxial growth of Pt and Pd and Pd(100) via spot profile analysis using conventional low-energy electron diffraction (LEED). We resolve a central-spike and diffuse component in the spot profiles, reflecting the layer-occupations and pair-correlations, respectively. Kinetic limitations inhibit layer-by-layer growth at low temperatures. Our data suggest diffusion switches on at ca. 150 K for Pt and ca. 170 K for Pd indicating activation barriers to surface diffusion of ca. 10 and ca. 13 kcal/mol, respectively. To clarify the role of diffusion in determining the resulting film morphology, we develop a growth model that incorporates the adsorption-site requirement and predicts intensity oscillations. We present a new procedure to experimentally determine out-of-phase scattering conditions. At these energies, ring-structure is evident in the profiles during Pd growth between ca. 200 and 400 K. We report ring intensity oscillations as a function of coverage, which demonstrate the filling of individual layers.

  12. 'Pd20Sn13' revisited: crystal structure of Pd6.69Sn4.31.

    Science.gov (United States)

    Klein, Wilhelm; Jin, Hanpeng; Hlukhyy, Viktor; Fässler, Thomas F

    2015-07-01

    The crystal structure of the title compound was previously reported with composition 'Pd20Sn13' [Sarah et al. (1981 ▸). Z. Metallkd, 72, 517-520]. For the original structure model, as determined from powder X-ray data, atomic coordinates from the isostructural compound Ni13Ga3Ge6 were transferred. The present structure determination, resulting in a composition Pd6.69Sn4.31, is based on single crystal X-ray data and includes anisotropic displacement parameters for all atoms as well as standard uncertainties for the atomic coordinates, leading to higher precision and accuracy for the structure model. Single crystals of the title compound were obtained via a solid-state reaction route, starting from the elements. The crystal structure can be derived from the AlB2 type of structure after removing one eighth of the atoms at the boron positions and shifting adjacent atoms in the same layer in the direction of the voids. One atomic site is partially occupied by both elements with a Pd:Sn ratio of 0.38 (3):0.62 (3). One Sn and three Pd atoms are located on special positions with site symmetry 2. (Wyckoff letter 3a and 3b).

  13. Isomerism in the "south-east" of $^{132}$Sn and a predicted neutron-decaying isomer in $^{129}$Pd

    CERN Document Server

    Yuan, Cenxi; Xu, Furong; Walker, P M; Podolyak, Zs; Xu, C; Ren, Z Z; Ding, B; Liu, M L; Liu, X Y; Xu, H S; Zhou, X H; Zhang, Y H; Zuo, W

    2016-01-01

    Excited states in neutron-rich nuclei located south-east of $^{132}$Sn are investigated by shell-model calculations. A new shell-model Hamiltonian is constructed for the present study. The proton-proton and neutron-neutron interactions of the Hamiltonian are obtained through the existing CD-Bonn $G$ matrix results, while the proton-neutron interaction across two major shells is derived from the monopole based universal interaction plus the M3Y spin-orbit force. The present Hamiltonian can reproduce well the experimental data available in this region, including one-neutron separation energies, level energies and the experimental $B(E2)$ values of isomers in $^{134,136,138}$Sn, $^{130}$Cd, and $^{128}$Pd. New isomers are predicted in this region, $e.g.$ in $^{135}$Sn, $^{131}$Cd, $^{129}$Pd, $^{132,134}$In and $^{130}$Ag, in which almost no excited states are known experimentally yet. In the odd-odd $^{132,134}$In and $^{130}$Ag, the predicted very long $E2$ life-times of the low-lying $5^{-}$ states are discus...

  14. Bulk metallic glass formation in the Pd-Ni-P and Pd-Cu-P alloy systems

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, R.B.; He, Y. [Los Alamos National Lab., NM (United States). Center for Materials Science

    1996-12-11

    Bulk metallic glasses were prepared in the Pd-Ni-P and Pd-Cu-P systems using a fluxing technique. The formation of bulk amorphous Pd-Cu-P alloys was reported here for the first time. For both alloy systems, bulk glass formation requires maintaining the phosphorus content near 20 at.%. In the Pd-Ni-P system, 10-mm diameter amorphous Pd{sub x}Ni{sub 80{minus}x}P{sub 20} rods can be formed for 25 {le} x {le} 60. In the Pd-Cu-P system, 7-mm diameter amorphous Pd{sub x}Cu{sub 80{minus}x}P{sub 20} rods can be produced for 40 {le} x {le} 60. From all the ternary alloys studied, Pd{sub 40}Ni{sub 40}P{sub 20} has the highest glass formability, and 25-mm diameter amorphous cylinders, 50 mm in length, can be easily fabricated. The glass stability of the Pd-Ni-P system is wider than that of the Pd-Cu-P system. For most bulk Pd-Ni-P glasses, {Delta}T > 90 K. The {Delta}T values of bulk amorphous Pd-Cu-P alloys are considerably smaller, ranging from 27 to 73 K. The elastic constants of bulk amorphous Pd-Ni-P and Pd-Cu-P alloys were determined using a resonant ultrasound spectroscopy technique. The Pd-Ni-P glasses are slightly stiffer than the Pd-Cu-P glasses. Within each alloy system, the Young`s modulus and the bulk modulus show little change with alloy composition. Of all the bulk glass forming systems so far investigated, the ternary Pd-Ni-P system has the best glass formability. This alloy was one of the first bulk glasses discovered, yet it still remains the best in terms of glass formability. Upon replacing part of Ni by Cu, the critical cooling rates are expected to be further reduced.

  15. The associations between PD-1, CTLA-4 gene polymorphisms and susceptibility to ankylosing spondylitis: a meta-analysis and systemic review.

    Science.gov (United States)

    Chen, Si; Li, Yuan; Deng, Chuiwen; Li, Jing; Wen, Xiaoting; Wu, Ziyan; Hu, Chaojun; Zhang, Shulan; Li, Ping; Zhang, Xuan; Zhang, Fengchun; Li, Yongzhe

    2016-01-01

    Previous surveys had evaluated the effects of the PD-1, CTLA-4 gene polymorphisms on susceptibility to ankylosing spondylitis (AS), but the results remained controversial. To briefly examine these consequences, a comprehensive meta-analysis was conducted to estimate the relationships between PD-1 rs11568821, rs2227982, rs2227981, CTLA-4 +49 A/G and -318 C/T polymorphisms and AS risk. The available articles dated to December 2014 were searched in the PUBMED, MEDLINE and EMBASE databases. The data of the genotypes and/or alleles for the PD-1 rs11568821, rs2227982, rs2227981, CTLA-4 +49 A/G and -318 C/T polymorphisms in the AS and control subjects were extracted, and statistical analysis was conducted by STATA 11.2 software. Summary odds ratios (ORs) with their 95 % confidence intervals (95 % CIs) were calculated to determine the strength of associations with fixed-effects or random-effects models. A total of eight published studies were finally involved in this meta-analysis. Meta-analysis of PD-1 rs2227982 polymorphism under the T allele versus C allele (OR 1.744, 95 % CI 1.477-2.059, P < 0.0001), TT+TC versus CC (OR 2.292, 95 % CI 1.654-3.175, P < 0.0001), TT versus CC (OR 1.883, 95 % CI 1.299-2.729, P = 0.001) revealed a significant association with AS. Our meta-analysis demonstrated that the rs2227982 polymorphism in the PD-1 gene might contribute to AS susceptibility. However, further studies with large sample sizes and among different ethnicity populations should be required to confirm this association.

  16. Molecular dynamics study of Cu-Pd ordered alloys

    Directory of Open Access Journals (Sweden)

    S. Özdemir Kart

    2008-11-01

    Full Text Available Purpose: The goal of the paper is to study the molecular dynamics of Cu-Pd ordered alloys.Design/methodology/approach: The thermal and mechanical properties of Cu, Pd pure metals and their ordered intermetallic alloys of Cu3Pd(L12 and CuPd3(L12 are studied by using the molecular dynamics simulation. The melting behavior of the metals considered in this work is studied by utilizing quantum Sutton-Chen (Q-SC many-body potential. The effects of temperature and concentration on the physical properties of Cu-Pd system are analyzed.Findings: A wide range of properties of Cu, Pd pure metals and their Cu3Pd and CuPd3 ordered intermetallics is presented. It was found that this potential is suitable to give the general characteristics of the melting process in these systems. Practical implications: The simulation results such as cohesive energy, density, elastic constants, bulk modulus, heat capacity, thermal expansion and melting points are in good agreement with the available experimental data and other theoretical calculations.Originality/value: To the best our knowledge this work presents, for the first time, a wide range of physical properties of alloys focusing on Cu-Pd ordered compounds.

  17. Superconductivity in Ta3Pd3Te14 with quasi-one-dimensional PdTe2 chains.

    Science.gov (United States)

    Jiao, Wen-He; He, Lan-Po; Liu, Yi; Xu, Xiao-Feng; Li, Yu-Ke; Zhang, Chu-Hang; Zhou, Nan; Xu, Zhu-An; Li, Shi-Yan; Cao, Guang-Han

    2016-02-15

    We report bulk superconductivity at 1.0 K in a low-dimensional ternary telluride Ta3Pd3Te14 containing edge-sharing PdTe2 chains along crystallographic b axis, similar to the recently discovered superconductor Ta4Pd3Te16. The electronic heat capacity data show an obvious anomaly at the transition temperature, which indicates bulk superconductivity. The specific-heat jump is ΔC/(γ(n)T(c)) ≈ 1.35, suggesting a weak coupling scenario. By measuring the low-temperature thermal conductivity, we conclude that Ta3Pd3Te14 is very likely a dirty s-wave superconductor. The emergence of superconductivity in Ta3Pd3Te14 with a lower T(c), compared to that of Ta4Pd3Te16, may be attributed to the lower density of states.

  18. A straightforward and effective strategy for controllable synthesis of Ag/Ag{sub 2}S and Ag/CdS heterojunction nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Xuandi [Southern Medical University, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Nanfang Hospital (China); Feng, Xiumei; Hu, Jianqiang, E-mail: jqhusc@scut.edu.cn [South China University of Technology, Key Lab of Fuel Cell Technology of Guangdong Province, Department of Chemistry, College of Chemistry and Chemical Engineering (China); Tan, Lishan [Southern Medical University, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Nanfang Hospital (China); Liu, Jianyu, E-mail: jyliu@scut.edu.cn; Chen, Yuyu; Deng, Xiulong [South China University of Technology, Key Lab of Fuel Cell Technology of Guangdong Province, Department of Chemistry, College of Chemistry and Chemical Engineering (China); Li, Aiqing, E-mail: liaiqing@smu.edu.cn [Southern Medical University, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Nanfang Hospital (China)

    2015-02-15

    Ag/Ag{sub 2}S heterojunction nanowires (HJNWs) have been successfully fabricated through one-pot solution-phase method, which were transferred into Ag/CdS HJNWs by cation exchange. The synthesis involved a template-less, non-seed, and one-pot solution-phase process to high-quality Ag/Ag{sub 2}S HJNWs. The sizes, positions, and spacing distances between the Ag{sub 2}S or CdS NPs of the growing Ag{sub 2}S and CdS NPs in the Ag/Ag{sub 2}S and Ag/CdS HJNWs could be finely tailored by reaction temperatures and PVP concentrations. By varying reaction temperature, the sizes and positions (tip or surface) of the growing Ag{sub 2}S and CdS NPs in the Ag/Ag{sub 2}S and Ag/CdS HJNWs could be effectively controlled while PVP concentration could tailor the sizes and spacing distances between the Ag{sub 2}S or CdS NPs of the growing Ag{sub 2}S and CdS NPs in the Ag/Ag{sub 2}S and Ag/CdS HJNWs. We also proposed a primary experimental model to illustrate the growth mechanism of the Ag/Ag{sub 2}S and Ag/CdS HJNWs.

  19. An efficient photochemical route to Pd nanoparticles; application to the one-step synthesis of Pd@polymer nanocomposite films

    Science.gov (United States)

    Wolak, Séverine; Vidal, Loïc; Becht, Jean-Michel; Michelin, Laure; Balan, Lavinia

    2016-08-01

    We have developed a facile, efficient, low cost and ‘green’ photochemical approach to preparing surfactant-free Pd nanoparticles and Pd-immobilized@acrylate photo-polymer films at room temperature, under air and without any additional treatment. The reaction system only includes a photo-initiator used as a generator of free radicals and a Pd(II) salt. In ethanol solution, the photochemical reduction of Pd(II) to Pd(0) generates very small metal particles with a narrow size distribution (2-4 nm). Furthermore, we have shown that the formation of Pd nanoparticles from a Pd(II) salt can be reversible thus allowing easy handling and safe storage with the possibility of generating the nanoparticles just before use. In the presence of an acrylate bifunctional monomer, Pd@polymer film was obtained through a ‘one-pot, one-step’ process resulting from a simultaneous photo-reduction of Pd(II) and photo-polymerization of acrylate units. The simultaneous generation of a 3D polymer network and of metal particles leads to a homogeneous distribution of Pd nanoparticles in the photo-polymer matrix with an average diameter of approximately 3.7 ± 1.1 nm. Such as-prepared Pd@polymer films were found to efficiently catalyze the Mizoroki-Heck reaction in the presence of only 0.9 mequiv. of supported palladium. The major interest of this arrangement is its recoverability and reusability, which makes it very attractive both from a practical and economical viewpoint. Finally, it is worth noting that this innovation offers a great advantage over concurrent methods in that it is simply generated within minutes, it is highly stable, and there is sharp monodispersity in the size of the Pd nanoparticles that can be stored for months without alteration of their physico-chemical properties and catalytic activity.

  20. Crystal clear: visualizing the intervention mechanism of the PD-1/PD-L1 interaction by two cancer therapeutic monoclonal antibodies

    Directory of Open Access Journals (Sweden)

    Shuguang Tan

    2016-11-01

    Full Text Available Abstract Antibody-based PD-1/PD-L1 blockade therapies have taken center stage in immunotherapies for cancer, with multiple clinical successes. PD-1 signaling plays pivotal roles in tumor-driven T-cell dysfunction. In contrast to prior approaches to generate or boost tumor-specific T-cell responses, antibody-based PD-1/PD-L1 blockade targets tumor-induced T-cell defects and restores pre-existing T-cell function to modulate antitumor immunity. In this review, the fundamental knowledge on the expression regulations and inhibitory functions of PD-1 and the present understanding of antibody-based PD-1/PD-L1 blockade therapies are briefly summarized. We then focus on the recent breakthrough work concerning the structural basis of the PD-1/PD-Ls interaction and how therapeutic antibodies, pembrolizumab targeting PD-1 and avelumab targeting PD-L1, compete with the binding of PD-1/PD-L1 to interrupt the PD-1/PD-L1 interaction. We believe that this structural information will benefit the design and improvement of therapeutic antibodies targeting PD-1 signaling.

  1. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>AgEcon Search is a free,open access repository of full-text scholarly literature in agricultural and applied economics,inclu-ding working papers,conference papers,and journal articles. AgEcon Search is co-sponsored by the Department of Applied Eco-nomics and the University Libraries at University of Minnesota and the Agricultural and Applied Economics Association. Research in Agricultural and Applied Economics collects,indexes,and electronically distributes full text copies of scholarly research in the

  2. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>AgEcon Search is a free,open access repository of full-text scholarly literature in agricultural and applied economics,including working papers,conference papers,and journal articles.AgEcon Search is co-sponsored by the Department of Applied Economics and the University Libraries at University of Minnesota and the Agricultural and Applied Economics Association.Research in Agricultural and Applied Economics collects,indexes,and electronically distributes full text copies of scholarly research in the broadly defined field of agricultural economics including sub disciplines such as agribusiness,food supply,natural resource economics,environmental eco-

  3. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>AgEcon Search is a free,open access repository of full-text scholarly literature in agricultural and applied economics,inclu-ding working papers,conference papers,and journal articles. AgEcon Search is co-sponsored by the Department of Applied Eco-nomics and the University Libraries at University of Minnesota and the Agricultural and Applied Economics Association. Researchin Agricultural and Applied Economics collects,indexes,and electronically distributes full text copies of scholarly research in the

  4. PD-L1 expression in non-small cell lung cancer : Correlations with genetic alterations

    NARCIS (Netherlands)

    Scheel, Andreas H.; Ansen, Sascha; Schultheis, Anne M.; Scheffler, Matthias; Fischer, Rieke N.; Michels, Sebastian; Hellmich, Martin; George, Julie; Zander, Thomas; Brockmann, Michael; Stoelben, Erich; Groen, Harry; Timens, Wim; Perner, Sven; von Bergwelt-Baildon, Michael; Buettner, Reinhard; Wolf, Juergen

    2016-01-01

    Inhibition of the PD-1/PD-L1 pathway may induce anticancer immune responses in non-small cell lung cancer (NSCLC). Two PD-L1 immunohistochemistry (IHC) assays have been approved as companion diagnostic tests for therapeutic anti-PD-1 antibodies. However, many aspects of PD-L1 prevalence and associat

  5. Improved ethanol electrooxidation performance by shortening Pd-Ni active site distance in Pd-Ni-P nanocatalysts

    Science.gov (United States)

    Chen, Lin; Lu, Lilin; Zhu, Hengli; Chen, Yueguang; Huang, Yu; Li, Yadong; Wang, Leyu

    2017-01-01

    Incorporating oxophilic metals into noble metal-based catalysts represents an emerging strategy to improve the catalytic performance of electrocatalysts in fuel cells. However, effects of the distance between the noble metal and oxophilic metal active sites on the catalytic performance have rarely been investigated. Herein, we report on ultrasmall (~5 nm) Pd-Ni-P ternary nanoparticles for ethanol electrooxidation. The activity is improved up to 4.95 A per mgPd, which is 6.88 times higher than commercial Pd/C (0.72 A per mgPd), by shortening the distance between Pd and Ni active sites, achieved through shape transformation from Pd/Ni-P heterodimers into Pd-Ni-P nanoparticles and tuning the Ni/Pd atomic ratio to 1:1. Density functional theory calculations reveal that the improved activity and stability stems from the promoted production of free OH radicals (on Ni active sites) which facilitate the oxidative removal of carbonaceous poison and combination with CH3CO radicals on adjacent Pd active sites.

  6. Elastic and electronic properties of antiperovskite-type Pd- and Pt-based ternary carbides from first-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Bannikov, V.V.; Ivanovskii, A.L., E-mail: ivanovskii@ihim.uran.ru

    2013-11-15

    Highlights: • 23 Pd- and Pt-based antiperovskite-type ternary carbides are probed from first principles. • Structural, elastic, electronic properties and inter-atomic bonding are evaluated. • A rich variety of mechanical and electronic properties was predicted. -- Abstract: By means of first-principles calculations, the structural, elastic, and electronic properties of a broad series of proposed Pd- and Pt-based antiperovskite-type ternary carbides AC(Pd,Pt){sub 3}, where A are Zn, Ca, Al, Ga, In, Ge, Hg, Sn, Cd, Pb, Ag, Sc, Ti, Y, Nb, Mo, and Ta, have been studied, and their stability, elastic constants, bulk, shear, and Young’s moduli, compressibility, Pugh’s indicator, Poisson’s ratio, indexes of elastic anisotropy, as well as electronic properties have been evaluated. We found that these materials should demonstrate a rich variety of mechanical and electronic properties depending on the type of A sublattices, which can include (unlike the majority of known 3d-metal-based antiperovskites) both sp elements and d atoms. We believe that the presented results will be useful for future synthesis of these phases, as well as for expanding our knowledge of this interesting group of antiperovskite-type materials.

  7. Ag nanotubes and Ag/AgCl electrodes in nanoporous membranes

    Energy Technology Data Exchange (ETDEWEB)

    Davenport, Matthew; Healy, Ken; Siwy, Zuzanna S, E-mail: zsiwy@uci.edu [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States)

    2011-04-15

    Miniaturization of the entire experimental setup is a key requirement for widespread application of nanodevices. For nanopore biosensing, integrating electrodes onto the nanopore membrane and controlling the pore length is important for reducing the complexity and improving the sensitivity of the system. Here we present a method to achieve these goals, which relies on electroless plating to produce Ag nanotubes in track-etched polymer nanopore templates. By plating from one side only, we create a conductive nanotube that does not span the full length of the pore, and thus can act as a nanoelectrode located inside the nanopore. To give optimal electrochemical behavior for sensing, we coat the Ag nanotube with a layer of AgCl. We characterize the behavior of this nanoelectrode by measuring its current-voltage response and find that, in most cases, the response is asymmetric. The plated nanopores have initial diameters between 100 and 300 nm, thus a range suitable for detection of viruses.

  8. Loading effect of Ag/AgO on the photocatalytic performance of ZnO rods

    Science.gov (United States)

    Samsuddin, Aida Fitri; Aziz, Siti Nor Qurratu Aini Abd; Pung, Swee-Yong

    2017-01-01

    The photocatalytic performance of ZnO rods in degradation of Rhodamine B dye under UV light was improved by 7.3% via deposition of Ag/AgO using 1.0 × 10-3 g mL-1 of silver nitrate solution. However, its photodegradation efficiency decreased with the increase in silver nitrate concentration which was used to prepare the Ag/AgO-ZnO rods. This result suggests that the loading of Ag/AgO on the surface of ZnO rods affected the photocatalytic performance differently. The scavenger study indicates that the main reactive species responsible for the degradation of Rhodamine B dye by Ag-/AgO-deposited ZnO rods were holes, followed by superoxide anion free radicals, hydroxyl free radicals and electrons. Based on these findings, a refined photodegradation mechanism of Rhodamine B by Ag/AgO-ZnO rods is proposed.

  9. AGS experiments: 1990, 1991, 1992. Ninth edition

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1993-04-01

    This report contains a description of the following: AGS Experimental Area - High Energy Physics FY 1993 and Heavy Ion Physics FY 1993; Table of Beam Parameters and Fluxes; Experiment Schedule ``as run``; Proposed 1993 Schedule; A listing of experiments by number; Two-page summaries of each experiment begin here, also ordered by number; Publications of AGS Experiments; and List of AGS Experimenters.

  10. Targeting PD-1/PD-L1 in lung cancer: current perspectives

    Directory of Open Access Journals (Sweden)

    González-Cao M

    2015-07-01

    Full Text Available María González-Cao,1 Niki Karachaliou,1 Santiago Viteri,1 Daniela Morales-Espinosa,1 Cristina Teixidó,2 Jesús Sánchez Ruiz,3 Miquel Ángel Molina-Vila,2 Mariacarmela Santarpia,4 Rafael Rosell1,2,5,61Translational Cancer Research Unit, Instituto Oncológico Dr Rosell, Quirón Dexeus University Hospital, Barcelona, Spain; 2Pangaea Biotech SL, Barcelona, Spain; 3Centro Nacional de Investigación Oncología (CNIO, Madrid, Spain; 4Medical Oncology Unit, Human Pathology Department, University of Messina, Messina, Italy; 5Cancer Biology and Precision Medicine Program, Catalan Institute of Oncology, Germans Trias i Pujol Health Sciences Institute and Hospital, Campus Can Ruti, Badalona, Barcelona, Spain; 6Fundación Molecular Oncology Research, Barcelona, SpainAbstract: Increased understanding of tumor immunology has led to the development of effective immunotherapy treatments. One of the most important advances in this field has been due to pharmacological design of antibodies against immune checkpoint inhibitors. Anti-PD-1/PD-L1 antibodies are currently in advanced phases of clinical development for several tumors, including lung cancer. Results from Phase I–III trials with anti-PD-1/PD-L1 antibodies in non-small-cell lung cancer have demonstrated response rates of around 20% (range, 16%–50%. More importantly, responses are long-lasting (median duration of response, 18 months and fast (50% of responses are detected at time of first tumor evaluation with very low grade 3–4 toxicity (less than 5%. Recently, the anti-PD-1 antibody pembrolizumab received US Food and Drug Administration (FDA breakthrough therapy designation for treatment of non-small-cell lung cancer, supported by data from a Phase Ib trial. Another anti-PD-1 antibody, nivolumab, has also been approved for lung cancer based on survival advantage demonstrated in recently released data from a Phase III trial in squamous cell lung cancer.Keywords: immunotherapy, immunoncology

  11. AGS 20th anniversary celebration

    Energy Technology Data Exchange (ETDEWEB)

    Baggett, N.V. (ed.)

    1980-05-22

    On May 22, 1980, a symposium was held at Brookhaven to celebrate the 20th birthday of the AGS, to recall its beginnings, and to review major discoveries that have been made with its beams. The talks at the symposium are recorded in this volume.

  12. AGS experiments, 1988, 1989, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1991-04-01

    This report contains: experimental areas layout; table of beam parameters and fluxes; experiment schedule as run''; experiment long range schedule; a listing of experiments by number; two-page summaries of each experiment begin here, also ordered by number; publications of AGS experiments; and list of experimenters.

  13. AGS experiments: 1985, 1986, 1987

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1987-01-01

    This report contains: Experimental areas layout, table of beam parameters and fluxes, experiment schedule ''as run,'' experiment long range schedule, a listing of experiments by number, two-page summaries of each experiment, also ordered by number, and publications of AGS experiments, 1982-1987.

  14. New structures in Pd-rich ordered alloys

    Science.gov (United States)

    Corbitt, Jacqueline; Gilmartin, Erin; Hart, Gus

    2010-10-01

    An intriguing intermetallic structure with 8:1 stoichiometry was discovered in the 1950s in the Pt-Ti system. Since then a handful of other Pt/Pd/Ni binary systems have been observed to exhibit this curious structure (Pt8Zr, Pd8Mo, Ni8Nb, etc). This ordered structure can significantly increase the hardness of an alloy. For jewelry applications involving Pt and Pd, international hallmarking standards require that the alloys be at least 95% pure by weight. However, Pt- and Pd-rich alloys are often soft when purity is high if the minority atoms are disordered. Because the 8:1 structure maintains a high weight percentage of Pt/Pd, it can satisfy purity standards while increasing performance. Recent calculations and experiments suggest that the 8:1 structure may form in about 20 previously unsuspected Pt/Pd binary systems. Using first-principles calculations and cluster expansion modeling, we have performed a ground state search to find the stable structures in Pd-Nb and Pd-Cu. In collaboration with Candace Lang's group at University of Capetown South Africa, we are working to experimentally validate the predicted ground states.

  15. Pembrolizumab: PD-1 inhibition as a therapeutic strategy in cancer.

    Science.gov (United States)

    McDermott, J; Jimeno, A

    2015-01-01

    Programmed cell death protein 1 (PD-1) and its ligands, programmed cell death 1 ligand 1 (PD-L1) and 2 (PD-L2) play an important role in regulating immune response through various mechanisms. This inhibitory action is thought to assist in immune evasion by cancer cells as PD-1, PD-L1 and PD-L2 have been found to be abnormally expressed by tumor cells and lymphocytes in the tumor microenvironment. Preclinical studies described PD-1 blockade resulting in tumor growth suppression and even decreased metastasis. This has led to the development of pembrolizumab (MK-3475), a highly selective, humanized monoclonal IgG4-kappa isotype antibody against PD-1. Early clinical trials have shown high tumor response rates and long duration of effect in previously treated advanced melanoma resulting in accelerated FDA approval for the drug in this situation. Pembrolizumab has also had success in non-small cell lung cancer and is being tested in multiple other tumor types. This review will discuss the development, preclinical data, pharmacokinetics and clinical efficacy to date of pembrolizumab.

  16. PD-1 Blockade Expands Intratumoral Memory T Cells

    DEFF Research Database (Denmark)

    Ribas, Antoni; Shin, Daniel Sanghoon; Zaretsky, Jesse

    2016-01-01

    Tumor responses to programmed cell death protein 1 (PD-1) blockade therapy are mediated by T cells, which we characterized in 102 tumor biopsies obtained from 53 patients treated with pembrolizumab, an antibody to PD-1. Biopsies were dissociated, and single-cell infiltrates were analyzed by multi...

  17. Biosupported Bimetallic Pd Au Nanocatalysts for Dechlorination of Environmental Contaminants

    Energy Technology Data Exchange (ETDEWEB)

    De Corte, S.; Fitts, J.; Hennebel, T.; Sabbe, T.; Bliznuk, V.; Verschuere, S.; van der Lelie, D.; Verstraete, W.; Boon, N.

    2011-08-30

    Biologically produced monometallic palladium nanoparticles (bio-Pd) have been shown to catalyze the dehalogenation of environmental contaminants, but fail to efficiently catalyze the degradation of other important recalcitrant halogenated compounds. This study represents the first report of biologically produced bimetallic Pd/Au nanoparticle catalysts. The obtained catalysts were tested for the dechlorination of diclofenac and trichloroethylene. When aqueous bivalent Pd(II) and trivalent Au(III) ions were both added to concentrations of 50 mg L{sup -1} and reduced simultaneously by Shewanella oneidensis in the presence of H{sub 2}, the resulting cell-associated bimetallic nanoparticles (bio-Pd/Au) were able to dehalogenate 78% of the initially added diclofenac after 24 h; in comparison, no dehalogenation was observed using monometallic bio-Pd or bio-Au. Other catalyst-synthesis strategies did not show improved dehalogenation of TCE and diclofenac compared with bio-Pd. Synchrotron-based X-ray diffraction, (scanning) transmission electron microscopy and energy dispersive X-ray spectroscopy indicated that the simultaneous reduction of Pd and Au supported on cells of S. oneidensis resulted in the formation of a unique bimetallic crystalline structure. This study demonstrates that the catalytic activity and functionality of possibly environmentally more benign biosupported Pd-catalysts can be improved by coprecipitation with Au.

  18. Regeneration of sulfur-fouled bimetallic Pd-based catalysts.

    Science.gov (United States)

    Chaplin, Brian P; Shapley, John R; Werth, Charles J

    2007-08-01

    Pd-based catalysts provide efficient and selective reduction of several drinking water contaminants, but their long-term application requires effective treatments for catalyst regeneration following fouling by constituents in natural waters. This studytested alumina-supported Pd-Cu and Pd-In bimetallic catalysts for nitrate reduction with H2 after sulfide fouling and oxidative regeneration procedures. Both catalysts were severely deactivated after treatment with microM levels of sulfide. Regeneration was attempted with dissolved oxygen, hydrogen peroxide, sodium hypochlorite, and heated air. Only sodium hypochlorite and heated air were effective regenerants, specifically restoring nitrate reduction rates for a Pd-In/gamma-Al2O3 catalyst from 20% to between 39 and 60% of original levels. Results from ICP-MS revealed that sodium hypochlorite caused dissolution of Cu from the Pd-Cu catalyst but that the Pd-In catalyst was chemically stable over a range of sulfide fouling and oxidative regenerative conditions. Analysis byXPS indicated that PdS and In2S3 complexes form during sulfide fouling, where sulfur is present as S2-, and that regeneration with sodium hypochlorite converts a portion of the S2- to S6+, with a corresponding increase in reduction rates. These results indicate that Pd-In catalysts show exceptional promise for being robust under fouling and regeneration conditions that may occur when treating natural waters.

  19. Electroanalysis of As(III) at nanodendritic Pd on PEDOT.

    Science.gov (United States)

    Dash, Sthitaprajna; Munichandraiah, N

    2014-04-01

    Nanodendritic Pd electrodeposited on poly(3,4-ethylenedioxythiophene) (PEDOT) modified Pd nanodendrite electrodes has been studied for electroanalysis of As(III) in 1 M HCl solution. The Pd nanodendrites are grown on a porous thin film of PEDOT by electrodeposition process. Pd-PEDOT/C electrodes are characterized by physicochemical and electrochemical studies. Cyclic voltammetry studies show that Pd-PEDOT/C electrodes exhibit greater electrocatalytic activity towards As(iii)/As(0) redox reaction than the Pd/C electrodes. Differential pulse anodic stripping voltammetry (DPASV) is performed for analysis of As(iii) ion at pH 1.0. The Pd-PEDOT/C electrode is highly sensitive towards As(III) detection with sensitivity of 1482 μA cm(-2) μM(-1). A wide detection range up to 10 μM and low detection limit of 7 nM (0.52 ppb) are obtained with a pre-deposition time of 120 s under optimum conditions. High sensitivity and low detection limit obtained on Pd-PEDOT/C, for the first time in the literature, are attractive from a practical view point. Interference studies of Cu(II) ions are investigated and it is observed that Cu(II) ions do not interfere.

  20. Pd基Heusler合金Pd2CrGa和Pd2FeGa的第一性原理研究%First-principles study on Pd-based Heusler alloy Pd2CrGa and Pd2FeGa

    Institute of Scientific and Technical Information of China (English)

    刘国平; 米传同; 钱帅; 余新泉; 赵昆; 于金

    2014-01-01

    运用基因遗传算法的晶格结构预测技术预测Pd基Heusler合金Pd 2 MnSn、Pd 2 CrGa和Pd 2 FeGa的结构;采用基于密度泛函理论(DFT)的投影缀加波(PAW)方法研究Pd 2 CrGa和Pd 2 FeGa的四方变形、磁性、态密度、弹性常数和声子谱线,最后通过Helmholtz自由能的计算预测了Pd 2 CrGa和Pd 2 FeGa的相变温度。结构预测显示:极限条件0 K时,Pd2MnSn以L21立方结构稳定存在,而Pd2CrGa和Pd2FeGa均以四方结构稳定存在。四方变形中,Pd2CrGa、Pd 2 FeGa在c/a<1.0和c/a>1.0处均有一个能量的局域最小值,分别对应一个稳定的结构。Pd 2 CrGa、Pd 2 FeGa在两种状态下均表现为铁磁性,Cr原子和Fe原子是总磁矩的主要贡献者。弹性常数计算结果显示:Pd 2 CrGa和Pd 2 FeGa仅在四方结构时才满足稳定性判据。c/a≈1.24处的四方结构Pd2CrGa转变为立方结构的相变温度在350 K左右, c/a≈1.30处的四方结构Pd2FeGa转变为立方结构的相变温度在130 K左右。%Based on genetic algorithm, the structures of Pd-based Heusler alloy Pd2MnSn, Pd2CrGa and Pd2FeGa were forecasted. The tetragonal distortion, magnetic, DOS elastic constants and phonon dispersion spectra of Pd2CrGa and Pd2FeGa were calculated by first-principles calculation based on DFT with projector augmented wave pseudopotential (PAW). At last, based on the result of Helmholtz free-energy, the phase transition temperatures of Pd2CrGa and Pd2FeGa were predicted. The crystal structure prediction shows that Pd2MnSn is L21 cubic structure, but Pd2CrGa and Pd2FeGa are tetragonal structures at 0 K. The tetragonal distortion analysis show that there are local minimums total energy atc/a1.0, which correspond to stable martensitic phases. Pd2MGa (M=Cr,Fe) are ferromagnetic in these two postures, and M (M=Cr,Fe) is the main magnetic contribution to its alloys, respectively. The elastic constants of Pd2CrGa, Pd2FeGa show that, cubic structure doesn

  1. Comparative study of antimicrobial activity of AgBr and Ag nanoparticles (NPs).

    Science.gov (United States)

    Suchomel, Petr; Kvitek, Libor; Panacek, Ales; Prucek, Robert; Hrbac, Jan; Vecerova, Renata; Zboril, Radek

    2015-01-01

    The diverse mechanism of antimicrobial activity of Ag and AgBr nanoparticles against gram-positive and gram-negative bacteria and also against several strains of candida was explored in this study. The AgBr nanoparticles (NPs) were prepared by simple precipitation of silver nitrate by potassium bromide in the presence of stabilizing polymers. The used polymers (PEG, PVP, PVA, and HEC) influence significantly the size of the prepared AgBr NPs dependently on the mode of interaction of polymer with Ag+ ions. Small NPs (diameter of about 60-70 nm) were formed in the presence of the polymer with low interaction as are PEG and HEC, the polymers which interact with Ag+ strongly produce nearly two times bigger NPs (120-130 nm). The prepared AgBr NPs were transformed to Ag NPs by the reduction using NaBH4. The sizes of the produced Ag NPs followed the same trends--the smallest NPs were produced in the presence of PEG and HEC polymers. Prepared AgBr and Ag NPs dispersions were tested for their biological activity. The obtained results of antimicrobial activity of AgBr and Ag NPs are discussed in terms of possible mechanism of the action of these NPs against tested microbial strains. The AgBr NPs are more effective against gram-negative bacteria and tested yeast strains while Ag NPs show the best antibacterial action against gram-positive bacteria strains.

  2. [PK/PD modeling of aminoglycoside nephrotoxicity].

    Science.gov (United States)

    Rougier, F; Corvaisier, S; Ducher, M; Claude, D; Jelliffe, R W; Maire, P

    2003-06-01

    Aminoglycosides are bactericidial antibiotics with a serum concentration-dependent activity. They are mainly eliminated by the kidneys and the main difficulty arising in clinical use is their uptake by the renal cortex which leads to nephrotoxicity. An ototoxicity is also reported. We propose a PK/PD modelling of aminoglycoside nephrotoxicity which unifies more fourty years of physiological knowledge. This deterministic model successively describes the pharmacokinetics of aminoglycosides, their storage into renal cortex, their effect on renal cells, their consequences on the renal function through tubuloglomerular feedback and the changes in the serum concentrations of creatinine that is considered as a toxicity marker. The simulation of the model displays the leading effect of the shape and daily-time of administration schedule on the search for minimizing toxicity.

  3. Thermodynamics of hydrogen in Pd nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Crespo, E.A. [Dpto. de Fisica, Fac. de Ingenieria, Universidad Nacional del Comahue, Buenos Aires 1400, 8300 Neuquen (Argentina); Claramonte, S. [Ing. de Materiales, Instituto Sabato, UNSAM/CNEA, Avda. Gral. Paz 1499, 1650 San Martin, Buenos Aires (Argentina); Ruda, M. [Centro Atomico Bariloche, 8400 Bariloche (Argentina); Centro Regional Universitario Bariloche, Universidad Nacional del Comahue, Bariloche (Argentina); De Debiaggi, S. Ramos [Dpto. de Fisica, Fac. de Ingenieria, Universidad Nacional del Comahue - CONICET, Buenos Aires 1400, 8300, Neuquen (Argentina)

    2010-06-15

    From the atomistic simulation of pressure-composition isotherms of hydrogen absorption of Pd nanoparticles we calculated thermodynamic properties and evaluated them as a function of particle size. In the particle range studied both vertical stroke {delta}H vertical stroke and vertical stroke {delta}S vertical stroke decreased with particle size towards the corresponding bulk values. H atoms were segregated to the subsurface of the particles forming a shell structure that may explain an initial plateau shown in the particles isotherms that is not present in bulk simulations. We used potentials of the embedded-atom type (EAM) to describe the interaction between atoms and we performed Monte Carlo simulations to calculate the isotherms. (author)

  4. Hydrogen evolution on Au(111) covered with submonolayers of Pd

    DEFF Research Database (Denmark)

    Björketun, Mårten; Karlberg, Gustav; Rossmeisl, Jan;

    2011-01-01

    . The energetics of adsorption and desorption of hydrogen on/from different types of sites on the Pd-Au(111) surface are assessed by means of density functional theory calculations combined with thermodynamic modeling. Based on the density functional and Monte Carlo data, the hydrogen evolution activity......A theoretical investigation of electrochemical hydrogen evolution on Au(111) covered with submonolayers of Pd is presented. The size and shape of monoatomically high Pd islands formed on the Au(111) surface are determined using Monte Carlo simulations, for Pd coverages varying from 0.02 to 0.95 ML...... line defects for Pd island formation and hydrogen evolution are discussed. It is argued, with support from theoretical data, that this kind of defects is likely to be responsible for a dramatic increase in activity observed experimentally [ChemPhysChem 7, 985 (2006); Electrochim. Acta 52, 5548 (2007...

  5. Atomic displacements due to interstitial hydrogen in Cu and Pd

    Indian Academy of Sciences (India)

    Hitesh Sharma; S Prakash

    2007-08-01

    The density functional theory (DFT) is used to study the atomic interactions in transition metal-based interstitial alloys. The strain field is calculated in the discrete lattice model using Kanzaki method. The total energy and hence atomic forces between interstitial hydrogen and transition metal hosts are calculated using DFT. The norm-conserving pseudopotentials for H, Cu and Pd are generated self-consistently. The dynamical matrices are evaluated considering interaction up to first nearest neighbors whereas impurity-induced forces are calculated with M32H shell (where M = Cu and Pd). The atomic displacements produced by interstitial hydrogen at the octahedral site in Cu and Pd show displacements of 7.36% and 4.3% of the first nearest neighbors respectively. Both Cu and Pd lattices show lattice expansion due to the presence of hydrogen and the obtained average lattice expansion / = 0.177 for Cu and 0.145 for Pd.

  6. Hydrogen Storage Performance in Pd/Graphene Nanocomposites.

    Science.gov (United States)

    Zhou, Chunyu; Szpunar, Jerzy A

    2016-10-05

    We have developed a Pd-graphene nanocomposite for hydrogen storage. The spherically shaped Pd nanoparticles of 5-45 nm in size are homogeneously distributed over the graphene matrix. This new hydrogen storage system has favorable features like desirable hydrogen storage capacity, ambient conditions of hydrogen uptake, and low temperature of hydrogen release. At a hydrogen charging pressure of 50 bar, the material could yield a gravimetric density of 6.7 wt % in the 1% Pd/graphene nanocomposite. As we increased the applied pressure to 60 bar, the hydrogen uptake capacity reached 8.67 wt % in the 1% Pd/graphene nanocomposite and 7.16 wt % in the 5% Pd/graphene nanocomposite. This system allows storage of hydrogen in amounts that exceed the capacity of the gravimetric target announced by the U.S. Department of Energy (DOE).

  7. Reorienting the immune system in the treatment of cancer by using anti-PD-1 and anti-PD-L1 antibodies

    DEFF Research Database (Denmark)

    Borch, Troels H; Donia, Marco; Andersen, Mads H

    2015-01-01

    Physiologically, the programmed death 1 (PD-1) pathway is involved in limiting the killing of bystander cells during an infection and controlling autoimmunity. However, cancers exploit this system to avoid immune killing, and PD-1 ligand 1 and 2 (PD-L1 and PD-L2) expression on tumor cells, as well...... as PD-1 expression on tumor-infiltrating lymphocytes, have shown to be negative prognostic factors. Promising clinical results have been obtained by PD-1 pathway blockade in a range of cancers while still maintaining a manageable toxicity profile, and two anti-PD-1 antibodies are now approved by the US...

  8. Chemical ordering in magnetic FePd/Pd (001) epitaxial thin films induced by annealing

    Science.gov (United States)

    Halley, D.; Gilles, B.; Bayle-Guillemaud, P.; Arenal, R.; Marty, A.; Patrat, G.; Samson, Y.

    2004-11-01

    Chemically disordered FePd epitaxial layers are grown at room temperature by molecular beam epitaxy on a Pd(001) buffer layer and then annealed in order to induce the chemically ordered L 10 (AuCu I) structure. Contrary to what is observed in the case of ordering during growth above room temperature, the ordered structure appears here with the three possible variants of the L 10 phase. The ratio of the three different variant volumes is set by the residual epitaxial strain in the layer before annealing. It thus explains that for long annealing times, the long-range order parameter associated with the L 10 variant with c along the (100) growth direction saturates at a value close to 0.65, and never reaches unity. Magnetic consequences of the ordering are studied.

  9. Reactions pd-->3He η and pd-->3He π+π- near the η threshold

    Science.gov (United States)

    Mayer, B.; Boudard, A.; Fabbro, B.; Garçon, M.; Kerboul, C.; Poitou, J.; Wellers, F.; Jacobs, W. W.; Saudinos, J.; Tomasi-Gustafsson, E.; Mouly, J. P.; Kessler, R. S.; Nefkens, B. M.; Tippens, B.; van der Schaaf, A.; Abegg, R.; van Oers, W. T.; Briscoe, W.; Petrov, A.; Moalem, A.

    1996-05-01

    The reaction pd-->3Heη has been studied with the SPES2 spectrometer, for proton energies between 0.2 MeV and 11 MeV above threshold. The total cross section rises from 0.25 to 0.40 μb in this region. The observed energy dependence can be attributed to the strong final state interaction. The angular distribution is nearly isotropic, consistent with S wave production. A measurement of the pd-->3Heπ+π- cross section in the threshold region is also presented. The setup, which is capable of producing 105 tagged η/s with only a few percent background, is used to investigate rare η decays.

  10. Direct electrospinning of Ag/polyvinylpyrrolidone nanocables

    DEFF Research Database (Denmark)

    Chen, Menglin; Havelund, Rasmus; Li, Qiang

    2011-01-01

    Core-sheath silver nanowire/polyvinylpyrrolidone (AgNW/PVP) nanocables have been fabricated via an efficient single-spinneret electrospinning method. The core-sheath structure is revealed by combining several characterization methods. A possible formation mechanism of the AgNW/PVP nanocable...... involving a strong stretching during the electrospinning process is proposed. Further, electrical measurements were performed on AgNW/PVP nanocables as well as bare AgNWs, which indicated the nanocables became insulating due to the isolation of highly conductive AgNWs by insulating PVP sheath. Therefore...

  11. Imaging of Dopamine in PD and Implications for Motor and Neuropsychiatric Manifestations of PD

    OpenAIRE

    Raul ede la Fuente-Fernandez

    2013-01-01

    Parkinson’s disease (PD) is characterized by dopamine depletion in the putamen, which leads to motor dysfunction. As the disease progresses, a substantial degree of dopamine depletion also occurs in caudate and nucleus accumbens. This may explain a number of neuropsychiatric manifestations, including depression, apathy, and cognitive decline. Dopamine replacement therapy partially restores motor function but long-term treatment is often associated with motor complications (motor fluctuations ...

  12. Methane catalytic combustion on Pd9/gamma-Al2O3 with different degrees of Pd oxidation.

    Science.gov (United States)

    Czekaj, Izabela; Kacprzak, Katarzyna A; Mantzaras, John

    2013-01-01

    This research is focused on the analysis of adsorbed CH4 intermediates at oxidized Pd9 nanoparticles supported on gamma-alumina. From first-principle density functional theory (DFT) calculations, several configurations, charge transfer and electronic density of states have been analyzed in order to determine feasible paths for the oxidation process. Furthermore methane oxidation cycles have been investigated on Pd nanoparticles with different degrees of oxidation. In case of low oxidized Pd nanoparticles, activation of methane is observed, whereby hydrogen from methane is adsorbed at one oxygen atom. This reaction is exothermic. In a subsequent step, two water molecules desorb. Additionally, a very interesting structural effect becomes evident; Pd-carbide formation, which is also an exothermic reaction. Furthermore, oxidation of such carbidized Pd-nanoparticles leads to CO2 formation, which is an endothermic reaction. One important result is that the support is involved in the CO2 formation. A different mechanism of methane oxidation was discovered for highly oxidized Pd nanoparticles. When the Pd nanoparticle is more strongly exposed to oxidative conditions, adsorption of methane is also possible, but it leads to carbonic acid production at the interface between the Pd nanoparticles and support. This process is endothermic.

  13. Scaling of crystal field parameters between Pd{sub 2}REIn and Pd{sub 2}RESn

    Energy Technology Data Exchange (ETDEWEB)

    Babateen, M. [Department of Physics, Loughborough University of Technology, Loughborough, Leics. LE11 3TU (United Kingdom); Neumann, K.U. [Department of Physics, Loughborough University of Technology, Loughborough, Leics. LE11 3TU (United Kingdom); Ziebeck, K.R.A. [Department of Physics, Loughborough University of Technology, Loughborough, Leics. LE11 3TU (United Kingdom)

    1995-02-09

    Experimentally it is found that crystal field (CF) parameters between the same rare earth compounds in the alloy series Pd{sub 2}REIn and Pd{sub 2}RESn (RE=rare earth element) exhibit scaling properties. A phenomenological model is put forward to explain this observation. ((orig.)).

  14. Structure of the Complex of Human Programmed Death 1, PD-1, and Its Ligand PD-L1

    NARCIS (Netherlands)

    Zak, Krzysztof M.; Kitel, Radoslaw; Przetocka, Sara; Golik, Przemyslaw; Guzik, Katarzyna; Musielak, Bogdan; Dömling, Alexander; Dubin, Grzegorz; Holak, Tad A.

    2015-01-01

    Summary Targeting the PD-1/PD-L1 immunologic checkpoint with monoclonal antibodies has recently provided breakthrough progress in the treatment of melanoma, non-small cell lung cancer, and other types of cancer. Small-molecule drugs interfering with this pathway are highly awaited, but their develop

  15. Development of Pd and Pd-Co catalysts supported on multi-walled carbon nanotubes for formic acid oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Acosta, D.; Godinez, Luis A.; Rodriguez, H.G.; Arriaga, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Parque Tecnologico Queretaro, Sanfandila, Pedro Escobedo, C.P. 76703 Queretaro (Mexico); Ledesma-Garcia, J. [Division de Investigacion y Posgrado, Facultad de Ingenieria, Universidad Autonoma de Queretaro, Cerro de las Campanas S/N, C.P. 76010, Queretaro, Qro. (Mexico); Alvarez-Contreras, L. [Centro de Investigacion en Materiales Avanzados S. C., Complejo Industrial Chihuahua, C.P. 31109, Chihuahua, Chih. (Mexico)

    2010-01-15

    Pd-Co and Pd catalysts were prepared by the impregnation synthesis method at low temperature on multi-walled carbon nanotubes (MWCNTs). The nanotubes were synthesized by spray pyrolysis technique. Both catalysts were obtained with high homogeneous distribution and particle size around 4 nm. The morphology, composition and electrocatalytic properties were investigated by transmission electron microscopy, scanning electron microscopy-energy dispersive X-ray analysis, X-ray diffraction and electrochemical measurements, respectively. The electrocatalytic activity of Pd and PdCo/MWCNTs catalysts was investigated in terms of formic acid electrooxidation at low concentration in H{sub 2}SO{sub 4} aqueous solution. The results obtained from voltamperometric studies showed that the current density achieved with the PdCo/MWCNTs catalyst is 3 times higher than that reached with the Pd/MWCNTs catalyst. The onset potential for formic acid electrooxidation on PdCo/MWCNTs electrocatalyst showed a negative shift ca. 50 mV compared with Pd/MWCNTs. (author)

  16. Realization of Ag-S codoped p-type ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tian Ning, E-mail: xtn9886@zju.edu.cn [Department of Science, Zhijiang College of Zhejiang University of Technology, Hangzhou, Zhejiang 310024 (China); Department of Physics, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Li, Xiang; Lu, Zhong [Department of Science, Zhijiang College of Zhejiang University of Technology, Hangzhou, Zhejiang 310024 (China); Chen, Yong Yue [Department of Physics, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Sui, Cheng Hua [Department of Science, Zhijiang College of Zhejiang University of Technology, Hangzhou, Zhejiang 310024 (China); Wu, Hui Zhen [Department of Physics, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang 310027 (China)

    2014-10-15

    Highlights: • Ag-S codoped p-type ZnO thin films have been fabricated. • The films exhibit low resistivity and high Hall mobility and hole concentration. • A ZnO:(Ag, S)/i-ZnO/ZnO:Al homojunction has been fabricated and shows rectifying behaviors. - Abstract: Ag-S codoped ZnO films have been grown on quartz substrates by e-beam evaporation at low temperature (100 °C). The effects of Ag{sub 2}S content on the structural and electrical properties of the films were investigated. The results showed that 2 wt% Ag{sub 2}S doped films exhibited p-type conduction, with a resistivity of 0.0347 Ω cm, a Hall mobility of 9.53 cm{sup 2} V{sup −1} s{sup −1}, and a hole concentration of 1.89 × 10{sup 19} cm{sup −3} at room temperature. The X-ray photoelectron spectroscopy measurements showed that Ag and S have been incorporated into the films. To further confirm the p-type conduction of Ag-S codoped ZnO films, a ZnO:(Ag, S)/i-ZnO/ZnO:Al homojunction was fabricated and rectifying behaviors of which was measured. High electrical performance and low growth temperature indicate that Ag{sub 2}S is a promising dopant to fabricate p-type Ag-S codoped ZnO films.

  17. Study of hyperfine interactions in intermetallic compounds Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In; Estudo de interacoes hiperfinas em compostos intermetalicos Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In e Ho(Ni,Pd)In

    Energy Technology Data Exchange (ETDEWEB)

    Lapolli, Andre Luis

    2006-07-01

    Systematic behavior of magnetic hyperfine field (B{sub hf}) in the intermetallic compounds Gd(Ni,Pd,Cu)In Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In was studied by Perturbed Gamma-Gamma Angular Correlation spectroscopy. The measurements of B{sub hf} were carried out at the rare earth atom and in sites using the nuclear probes {sup 140}Ce and {sup 11}'1Cd respectively. The variation of hyperfine field with temperature, in most cases, follows the Brillouin function predicted from the molecular field theory. The hyperfine field values at rare earth atom sites obtained from {sup 140}Ce probe as well as at in sites obtained from {sup 111}Cd probe for each series of compounds were extrapolated to zero Kelvin B{sub hf}(T=0) from these curves. These values were compared with the values of the literature for other compounds containing the same rare earth element and all of them show a linear relationship with the ordering temperature. This indicates that the main contribution to B{sub hf} comes from the conduction electron polarization (CEP) through Fermi contact interaction and the principal mechanism of magnetic interaction in these compounds can be described by the RKKY type interaction. The values of B{sub hf}(T=0) for each family of intermetallic compounds RNiIn and RPdIn when plotted as a function of 4f spin projection of rare earth element also shows a linear relationship. Exceptions are the results for the compounds RNiIn obtained with {sup 111}Cd probe where a small deviation from linearity is observed. The results of the measurements carried out with the {sup 111}Cd probe were also analyzed to obtain the hyperfine parameters of the quadrupole interaction as a function of temperature for RPdln and GdNiIn compounds. The results show that for the compound GdPdIn there might be some Gd-In disorder at high temperature. (author)

  18. Alloying Au surface with Pd reduces the intrinsic activity in catalyzing CO oxidation

    KAUST Repository

    Qian, Kun

    2016-03-30

    © 2016. Various Au-Pd/SiO2 catalysts with a fixed Au loading but different Au:Pd molar ratios were prepared via deposition-precipitation method followed by H2 reduction. The structures were characterized and the catalytic activities in CO oxidation were evaluated. The formation of Au-Pd alloy particles was identified. The Au-Pd alloy particles exhibit enhanced dispersions on SiO2 than Au particles. Charge transfer from Pd to Au within Au-Pd alloy particles. Isolated Pd atoms dominate the surface of Au-Pd alloy particles with large Au:Pd molar ratios while contiguous Pd atoms dominate the surface of Au-Pd alloy particles with small Au:Pd molar ratios. Few synergetic effect of Au-Pd alloy occurs on catalyzing CO oxidation under employed reaction conditions. Alloying Au with Pd reduces the intrinsic activity in catalyzing CO oxidation, and contiguous Pd atoms on the Au-Pd alloy particles are capable of catalyzing CO oxidation while isolated Pd atoms are not. These results advance the fundamental understandings of Au-Pd alloy surfaces in catalyzing CO oxidation.

  19. Corrosion resistance of amorphous and crystalline Pd40Ni40P20 alloys in aqueous solutions

    DEFF Research Database (Denmark)

    Wu, Y.F.; Chiang, Wen-Chi; Chu, J.;

    2006-01-01

    The corrosion behaviors of amorphous and crystalline Pd40Ni40P20 alloys in various aqueous solutions are reported in this paper. The corrosion resistance of crystalline (annealed) Pd40Ni40P20 is better than that of amorphous Pd40Ni40P20 in various corrosive solutions, due to crystalline Pd40Ni40P20...... and mainly consists of inert Pd5P2, NI3P, Ni2Pd2P and noble Pd phases. These inert and noble properties result in a higher corrosion resistance in crystalline Pd40Ni40P20....

  20. Blockade of PD-1/PD-L1 promotes adoptive T-cell immunotherapy in a tolerogenic environment.

    Directory of Open Access Journals (Sweden)

    Stephen J P Blake

    Full Text Available Adoptive cellular immunotherapy using in vitro expanded CD8+ T cells shows promise for tumour immunotherapy but is limited by eventual loss of function of the transferred T cells through factors that likely include inactivation by tolerogenic dendritic cells (DC. The co-inhibitory receptor programmed death-1 (PD-1, in addition to controlling T-cell responsiveness at effector sites in malignancies and chronic viral diseases is an important modulator of dendritic cell-induced tolerance in naive T cell populations. The most potent therapeutic capacity amongst CD8+ T cells appears to lie within Tcm or Tcm-like cells but memory T cells express elevated levels of PD-1. Based on established trafficking patterns for Tcm it is likely Tcm-like cells interact with lymphoid-tissue DC that present tumour-derived antigens and may be inherently tolerogenic to develop therapeutic effector function. As little is understood of the effect of PD-1/PD-L1 blockade on Tcm-like CD8+ T cells, particularly in relation to inactivation by DC, we explored the effects of PD-1/PD-L1 blockade in a mouse model where resting DC tolerise effector and memory CD8+ T cells. Blockade of PD-1/PD-L1 promoted effector differentiation of adoptively-transferred Tcm-phenotype cells interacting with tolerising DC. In tumour-bearing mice with tolerising DC, effector activity was increased in both lymphoid tissues and the tumour-site and anti-tumour activity was promoted. Our findings suggest PD-1/PD-L1 blockade may be a useful adjunct for adoptive immunotherapy by promoting effector differentiation in the host of transferred Tcm-like cells.

  1. Effects of Ni{sub 3}Sn{sub 4} and (Cu,Ni){sub 6}Sn{sub 5} intermetallic layers on cross-interaction between Pd and Ni in solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Yong-Ho [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Division of Advanced Circuit Interconnect, Samsung Electro-Mechanics Co., Ltd., Suwon 443-743 (Korea, Republic of); Chung, Bo-Mook [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Department of Research and Development, KPM TECH, Ansan 425-090 (Korea, Republic of); Choi, Young-Sik [Division of Advanced Circuit Interconnect, Samsung Electro-Mechanics Co., Ltd., Suwon 443-743 (Korea, Republic of); Choi, Jaeho [Department of Advanced Metal and Materials Engineering, Gangneung-Wonju National University, Gangneung 210-702 (Korea, Republic of); Huh, Joo-Youl, E-mail: jyhuh@korea.ac.kr [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

    2013-12-05

    Highlights: •Ni{sub 3}Sn{sub 4} acts as a source of Ni atoms, leading to a strong cross-interaction with Pd. •(Cu,Ni){sub 6}Sn{sub 5} is an effective Ni diffusion barrier, inhibiting Pd resettlement. •Dissolution kinetics of (Pd,Ni)Sn{sub 4} was interpreted based on the Sn–Ni–Pd isotherm. •Cu addition to solder alleviates the (Pd,Ni)Sn{sub 4}-related risk of reliability deterioration. -- Abstract: We examined the effects of layers of intermetallic compound (IMC) Ni{sub 3}Sn{sub 4} and (Cu,Ni){sub 6}Sn{sub 5} formed at the solder/Ni interface, on the cross-interactions between Pd and Ni during solid-state aging and reflow soldering. Two types of diffusion couples, Pd/Sn/Ni and Pd/Sn–Cu/Ni, were aged at 150 °C to study the solid-state interactions. In contrast to the Pd/Sn/Ni couples in which a Ni{sub 3}Sn{sub 4} layer formed at the Ni interface, the Pd/Sn–Cu/Ni couple where a (Cu,Ni){sub 6}Sn{sub 5} layer formed at the Ni interface exhibited no significant interaction between Pd and Ni. The (Cu,Ni){sub 6}Sn{sub 5} layer acted as an effective barrier against Ni diffusion and thus inhibited the resettlement of (Pd,Ni)Sn{sub 4} onto the Ni interface. For the interaction during reflow, Sn–3.5Ag and Sn–3.0Ag–0.5Cu solder balls were isothermally reflowed on an electroless Ni(P)/electroless Pd/immersion Au (ENEPIG) surface finish at 250 °C, and the dissolution kinetics of the (Pd,Ni)Sn{sub 4} particles converted from the 0.2-μm-thick Pd-finish layer were examined. The spalled (Pd,Ni)Sn{sub 4} particles very quickly dissolved into the molten solder when the IMC layer formed on the Ni substrate was (Cu,Ni){sub 6}Sn{sub 5} rather than Ni{sub 3}Sn{sub 4}. The dependence of the dissolution kinetics of the spalled (Pd,Ni)Sn{sub 4} particles on the IMC layers was rationalized on the basis of a Sn–Ni–Pd isotherm at 250 °C. The present study suggests that the formation of a dense (Cu,Ni){sub 6}Sn{sub 5} layer at the solder/Ni interface can effectively

  2. Liquid phase catalytic hydrodebromination of tetrabromobisphenol A on supported Pd catalysts

    Science.gov (United States)

    Wu, Ke; Zheng, Mengjia; Han, Yuxiang; Xu, Zhaoyi; Zheng, Shourong

    2016-07-01

    Tetrabromobisphenol A (TBBPA) is a widely used brominated flame retardant and reductive debromination is an effective method for the abatement of TBBPA pollution. In this study, Pd catalysts supported on TiO2, CeO2, Al2O3 and SiO2 were prepared by the impregnation (the resulting catalyst denoted as im-Pd/support), deposition-precipitation (the resulting catalyst denoted as dp-Pd/support), and photo-deposition (the resulting catalyst denoted as pd-Pd/support) methods. The catalysts were characterized by N2 adsorption-desorption isotherm, X-ray diffraction, transmission electron microscopy, measurement of zeta potential, CO chemisorption, and X-ray photoelectron spectroscopy. The results showed that at an identical Pd loading amount (2.0 wt.%) Pd particle size in dp-Pd/TiO2 was much smaller than those in im-Pd/TiO2 and pd-Pd/TiO2. Pd particle size of the dp-Pd/TiO2 catalyst increased with Pd loading amount. Additionally, Pd particles in the dp-Pd/TiO2 catalysts were positively charged due to the strong metal-support interaction, whereas the cationization effect was gradually attenuated with the increase of Pd loading amount. For the liquid phase catalytic hydrodebromination (HDB) of TBBPA, tri-bromobisphenol A (tri-BBPA), di-bromobisphenol A (di-BBPA), and mono-bromobisphenol A (mono-BBPA) were identified as the intermediate products, indicative of a stepwise debromination process. The catalytic HDB of TBBPA followed the Langmuir-Hinshelwood model, reflecting an adsorption enhanced catalysis mechanism. At an identical Pd loading amount, the Pd catalyst supported on TiO2 exhibited a much higher catalytic activity than those on other supports. Furthermore, dp-Pd/TiO2 was found to be more active than im-Pd/TiO2 and pd-Pd/TiO2.

  3. Photodeposited Pd Nanoparticles with Disordered Structure for Phenylacetylene Semihydrogenation

    Science.gov (United States)

    Fan, Qining; He, Sha; Hao, Lin; Liu, Xin; Zhu, Yue; Xu, Sailong; Zhang, Fazhi

    2017-01-01

    Developing effective heterogeneous metal catalysts with high selectivity and satisfactory activity for chemoselective hydrogenation of alkyne to alkene is of great importance in the chemical industry. Herein, we report our efforts to fabricate TiO2-supported Pd catalysts by a photodeposition method at room temperature for phenylacetylene semihydrogenation to styrene. The resulting Pd/TiO2 catalyst, possessing smaller Pd ensembles with ambiguous lattice fringes and more low coordination Pd sites, exhibits higher styrene selectivity compared to two contrastive Pd/TiO2 samples with larger ensembles and well-organized crystal structure fabricated by deposition-precipitation or photodeposition with subsequent thermal treatment at 300 °C. The sample derived from photodeposition exhibits greatly slow styrene hydrogenation in kinetic evaluation because the disordered structure of Pd particles in photodeposited Pd/TiO2 may prevent the formation of β-hydride phases and probably produce more surface H atoms, which may favor high styrene selectivity. PMID:28176843

  4. Cumene hydroperoxide hydrogenation over Pd/C catalysts.

    Science.gov (United States)

    Zhu, Qing-cai; Shen, Ben-xian; Ling, Hao; Gu, Rong

    2010-03-15

    Pd/C catalysts were prepared by wet impregnation using K(2)PdCl(4) as precursor and their performance in hydrogenation of cumene hydroperoxide (CHP) was investigated. The catalytic activity was examined on the formaldehyde-reduced and on the hydrogen-reduced Pd/C catalysts. Results from XRD, TEM and CO chemisorption showed that reduction methods have a significant impact on the palladium particles size of resulting catalysts. Formaldehyde-reduced Pd/C catalyst has larger palladium particles than hydrogen-reduced Pd/C catalyst. Consequently, higher activity but lower selectivity to alpha-cumyl alcohol (CA) was obtained on formaldehyde-reduced Pd/C catalyst. Moreover, hydrogenation of CHP over hydrogen-reduced Pd/C catalyst can give similar CA selectivity to Na(2)SO(3) reduction process, an industrial process for CA production. High rate of CHP conversion and CA selectivity can be obtained at an elevated temperature and H(2) pressure. Kinetics studies revealed that CHP hydrogenation is zero-order for CHP concentration and the activation energy was calculated to be 13.6 kJ/mol.

  5. Formation of Cu/Pd bimetallic crystals by electrochemical deposition

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, A.E. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Avda. Alem 1253, 8000 Bahia Blanca (Argentina); Salinas, D.R., E-mail: dsalinas@uns.edu.a [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Avda. Alem 1253, 8000 Bahia Blanca (Argentina)

    2010-04-15

    The early stages of the palladium electrodeposition process onto a vitreous carbon (VC) substrate as well as the deposition of Cu on such Pd/VC modified surface were investigated using classical electrochemical techniques, atomic force microscopy (AFM) and scanning electron microscopy (SEM). Within the potential range considered the kinetics of the Pd electrodeposition from a PdCl{sub 2} acid solution can be described by a model involving progressive nucleation on active sites and diffusion-controlled 3D growth. The nucleation rate constant, A{sub 0}, and the number of active sites of the substrate, N{sub 0}, were determined from the analysis of potentiostatic current transients on the basis of an existing theoretical model. The AFM images corroborated the progressive nucleation mechanism showing irregular palladium crystals randomly distributed over the VC surface, with different sizes and 3D morphological characteristics. The electrodeposition of Cu was carried out onto the characterized Pd/VC modified surface from a Cu{sup 2+} containing solution using a well defined polarization routine. The SEM/EDX images confirmed the formation of Cu/Pd bimetallic crystals uniformly distributed on the VC surface and the in situ AFM images obtained during this process corroborated that Cu formed a core-shell structure with the Pd crystals. Nevertheless, the subsequent anodic stripping produced only a partial dissolution of the Cu deposits, and therefore, the formation of a Cu/Pd alloy could be inferred.

  6. Polymorphism of LiAg

    Science.gov (United States)

    Pavlyuk, V. V.; Dmytriv, G. S.; Tarasiuk, I. I.; Chumak, I. V.; Pauly, H.; Ehrenberg, H.

    2010-02-01

    A phase transition from the cubic CsCl-type structure (Pm-3m space group) into a tetragonal UPb-type structure (I4 1/amd) is observed for the LiAg binary compound at ambient conditions. The crystal structure of the tetragonal modification of the LiAg binary compound was solved by direct methods in SHELXS on the base of structure factors which were extracted from a powder diffraction pattern and refined by SHELXL and the Rietveld method ( a = 3.9605(1), c = 8.2825(2) Å, Bragg R-factor = 4.81, Rf-factor = 4.87). Elevated temperatures and/or a small Li-excess versus the equimolar composition favour the cubic structure whereas ambient and lower temperatures and/or a small Li-deficiency stabilize the tetragonal structure. This reconstructive transition is reversible but proceeds slowly.

  7. Ordered Porous Pd Octahedra Covered with Monolayer Ru Atoms.

    Science.gov (United States)

    Ge, Jingjie; He, Dongsheng; Bai, Lei; You, Rui; Lu, Haiyuan; Lin, Yue; Tan, Chaoliang; Kang, Yan-Biao; Xiao, Bin; Wu, Yuen; Deng, Zhaoxiang; Huang, Weixin; Zhang, Hua; Hong, Xun; Li, Yadong

    2015-11-25

    Monolayer Ru atoms covered highly ordered porous Pd octahedra have been synthesized via the underpotential deposition and thermodynamic control. Shape evolution from concave nanocube to octahedron with six hollow cavities was observed. Using aberration-corrected high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy, we provide quantitative evidence to prove that only a monolayer of Ru atoms was deposited on the surface of porous Pd octahedra. The as-prepared monolayer Ru atoms covered Pd nanostructures exhibited excellent catalytic property in terms of semihydrogenation of alkynes.

  8. Reaction dynamics of initial O2 sticking on Pd(100).

    Science.gov (United States)

    den Dunnen, Angela; Wiegman, Sandra; Jacobse, Leon; Juurlink, Ludo B F

    2015-06-07

    We have determined the initial sticking probability of O2 on Pd(100) using the King and Wells method for various kinetic energies, surface temperatures, and incident angles. The data suggest two different mechanisms to sticking and dissociation. Dissociation proceeds mostly through a direct process with indirect dissociation contributing only at low kinetic energies. We suggest a dynamical precursor state to account for the indirect dissociation channel, while steering causes the high absolute reactivity. A comparison of our results to those previously obtained for Pd(111) and Pd(110) highlights how similar results for different surfaces are interpreted to suggest widely varying dynamics.

  9. Reaction dynamics of initial O2 sticking on Pd(100)

    Science.gov (United States)

    den Dunnen, Angela; Wiegman, Sandra; Jacobse, Leon; Juurlink, Ludo B. F.

    2015-06-01

    We have determined the initial sticking probability of O2 on Pd(100) using the King and Wells method for various kinetic energies, surface temperatures, and incident angles. The data suggest two different mechanisms to sticking and dissociation. Dissociation proceeds mostly through a direct process with indirect dissociation contributing only at low kinetic energies. We suggest a dynamical precursor state to account for the indirect dissociation channel, while steering causes the high absolute reactivity. A comparison of our results to those previously obtained for Pd(111) and Pd(110) highlights how similar results for different surfaces are interpreted to suggest widely varying dynamics.

  10. Improved Method for PD-Quantification in Power Cables

    DEFF Research Database (Denmark)

    Holbøll, Joachim T.; Villefrance, Rasmus; Henriksen, Mogens

    1999-01-01

    n this paper, a method is described for improved quantification of partial discharges(PD) in power cables. The method is suitable for PD-detection and location systems in the MHz-range, where pulse attenuation and distortion along the cable cannot be neglected. The system transfer function...... was calculated and measured in order to form basis for magnitude calculation after each measurements. --- Limitations and capabilities of the method will be discussed and related to relevant field applications of high frequent PD-measurements. --- Methods for increased signal/noise ratio are easily implemented...

  11. Frequency Dependent PD-pulse Distortion in Rotating Machines

    DEFF Research Database (Denmark)

    Holbøll, Joachim T.; Henriksen, Mogens

    1996-01-01

    In this contribution, the authors present results from investigations on the distortion of PD pulses in the stator winding of a 10 kV asynchronous motor. In order to determine the distortion of PD pulses from different, well defined parts in the winding, the following two techniques were used...... of the current transformer based detection method, when being applied to rotating machines. The results are discussed with regard to the practical application of PD detection systems on rotating machines, particularly considering aspects of range and applicability of systems in the HF ranges...

  12. PD Controller Structures: Comparison and Selection for an Electromechanical System

    Directory of Open Access Journals (Sweden)

    Farhan A. Salem

    2015-01-01

    Full Text Available Many different PD controller modeling, configurations and control algorithms have been developed. These methods differ in their theoretical basis and performance under the changes of system conditions. In the present paper we review the methods used in the design of PD control systems. We highlight the main difficulties and summarize the more recent developments in their control techniques. Intelligent control systems like PD fuzzy control can be used to emulate the qualitative aspects of human knowledge with several advantages such as universal approximation theorem and rule-based algorithms.

  13. Enhanced formic acid oxidation on Cu-Pd nanoparticles

    Science.gov (United States)

    Dai, Lin; Zou, Shouzhong

    Developing catalysts with high activity and high resistance to surface poisoning remains a challenge in direct formic acid fuel cell research. In this work, copper-palladium nanoparticles were formed through a galvanic replacement process. After electrochemically selective dissolution of surface Cu, Pd-enriched Cu-Pd nanoparticles were formed. These particles exhibit much higher formic acid oxidation activities than that on pure Pd nanoparticles, and they are much more resistant to the surface poisoning. Possible mechanisms of catalytic activity enhancement are briefly discussed.

  14. Flower-like Ag/AgCl microcrystals: Synthesis and photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Daupor, Hasan; Wongnawa, Sumpun, E-mail: sumpun.w@psu.ac.th

    2015-06-01

    Silver/silver chloride (Ag/AgCl) composites with a novel flower-like morphology were prepared via a hot precipitation assisted by the vinyl acetate monomer (VAM) route. An aqueous solution of AlCl{sub 3} was mixed with the vinyl acetate monomer and acetic acid before adding a AgNO{sub 3} solution at a temperature of 100 °C. The octapod shaped flower-like Ag/AgCl particles (or “flower-like Ag/AgCl” hereinafter) has eight petals each of which was about 7–11 μm in length. The flower-like octapods were formed by preferential overgrowth along the <111> directions of the cubic seeds. Detailed studies of the growth process at different AlCl{sub 3} concentrations revealed that the concave cube developed into a Rubik's cube where eight corners grew further into the flower-like structures. The VAM and acetic acid concentration strongly affected the growth of the Ag/AgCl to the flower-like structure and their optimum concentrations were determined. The morphologies of these particles were carefully examined by scanning electron microscopy (SEM). The crystal structures and orientation relationship were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–visible diffused reflectance spectroscopy (DRS). The flower-like Ag/AgCl microcrystals were tested for their photocatalytic degradation of orange G dye (OG) catalyzed by visible light. From comparative test runs, the flower-like Ag/AgCl exhibited better photocatalytic activity than simple and commercial Ag/AgCl particles. - Highlights: • Interesting transformation of microcrystals Ag/AgCl from concave cube via Rubik's cube to flower-like shape. • The first to use VAM as morphology control reagent. • High photocatalytic activity under visible light irradiation.

  15. Influence of Preparation Condition on the PdHx Phase of Pd/C Catalyst%制备条件对Pd/C催化剂活性相PdHx的影响

    Institute of Scientific and Technical Information of China (English)

    郇昌永; 马磊; 季来军; 郑遗凡; 李小年

    2013-01-01

    PdHx phase is an important reactive species in the Pd/C catalyst. The Pd/C catalyst with high content of PdHx phase was controllably prepared by the impregnation-hydrazine hydrate reduction method, and the influences of reduction methods, reduction conditions and the pretreatment conditions of the activated carbon on the PdHx content were investigated by XRD, XPS and TEM. By using the amination of 2,6-dimethyl phenol in the absence of hydrogen as a probe reaction, the relationship between PdHx content and catalytic activity was also studied. The results show that the Pd/C catalyst with high amount of PdHx can be obtained by using activated carbon support pretreated with 2.5%(wt) HNO3 and reducing the catalyst with hydrazine hydrate as reductor at 40℃. And over this catalyst the conversion of 2,6-dimethylphenol and the selectivity for 2,6-dimethylaniline are as high as 59.8%and 87.3%, respectively. It shows that the PdHx is the reactive phase of amiation reaction and its content is closely related to the concentration of HNO3 in the pretreatment process.%PdHx相是Pd/C催化剂中一种重要的活性物种。研究以浸渍-水合肼还原法制备出PdHx含量较高的Pd/C催化剂,通过XRD、XPS和TEM等表征方法研究了还原方式和条件及载体活性炭的预处理条件对催化剂中PdHx含量的影响,以无氢条件下的2,6-二甲基苯酚胺化法合成2,6-二甲基苯胺作为探针反应,验证了PdHx含量与催化活性的相关性。结果表明:以2.5%(wt)硝酸预处理的活性炭为载体,水合肼为还原剂,在40℃还原制得的催化剂具有较高的PdHx含量,以其为催化剂时原料的转化率和产品的选择性分别高达59.8%和87.3%。说明PdHx是该反应的活性相,其含量与载体预处理时的硝酸浓度密切相关。

  16. Capacitive deionization of seawater effected by nano Ag and Ag@C on graphene.

    Science.gov (United States)

    Cai, P-F; Su, C-J; Chang, W-T; Chang, F-C; Peng, C-Y; Sun, I-W; Wei, Y-L; Jou, C-J; Wang, H Paul

    2014-08-30

    Drinking water shortage has become worse in recent decades. A new capacitive deionization (CDI) method for increasing water supplies through the effective desalination of seawater has been developed. Silver as nano Ag and Ag@C which was prepared by carbonization of the Ag(+)-β-cyclodextrin complex at 573 K for 30 min can add the antimicrobial function into the CDI process. The Ag@C and Ag nanoparticles dispersed on reduced graphene oxide (Ag@C/rGO and nano Ag/rGO) were used as the CDI electrodes. The nano Ag/rGO and Ag@C/rGO electrodes can reduce the charging resistant, and enhance the electrosorption capability. Better CDI efficiencies with the nano Ag/rGO and Ag@C/rGO electrodes can therefore be obtained. When reversed the voltage, the electrodes can be recovered up to 90% within 5 min. This work presents the feasibility for the nano Ag and Ag@C on rGO electrodes applied in CDI process to produce drinking water from seawater or saline water.

  17. Comparative reliability studies and analysis of Au, Pd-coated Cu and Pd-doped Cu wire in microelectronics packaging.

    Science.gov (United States)

    Chong Leong, Gan; Uda, Hashim

    2013-01-01

    This paper compares and discusses the wearout reliability and analysis of Gold (Au), Palladium (Pd) coated Cu and Pd-doped Cu wires used in fineline Ball Grid Array (BGA) package. Intermetallic compound (IMC) thickness measurement has been carried out to estimate the coefficient of diffusion (Do) under various aging conditions of different bonding wires. Wire pull and ball bond shear strengths have been analyzed and we found smaller variation in Pd-doped Cu wire compared to Au and Pd-doped Cu wire. Au bonds were identified to have faster IMC formation, compared to slower IMC growth of Cu. The obtained weibull slope, β of three bonding wires are greater than 1.0 and belong to wearout reliability data point. Pd-doped Cu wire exhibits larger time-to-failure and cycles-to-failure in both wearout reliability tests in Highly Accelerated Temperature and Humidity (HAST) and Temperature Cycling (TC) tests. This proves Pd-doped Cu wire has a greater potential and higher reliability margin compared to Au and Pd-coated Cu wires.

  18. Metastatic basal cell carcinoma with amplification of PD-L1: exceptional response to anti-PD1 therapy

    Science.gov (United States)

    Ikeda, Sadakatsu; Goodman, Aaron M; Cohen, Philip R; Jensen, Taylor J; Ellison, Christopher K; Frampton, Garrett; Miller, Vincent; Patel, Sandip P; Kurzrock, Razelle

    2016-01-01

    Metastatic basal cell carcinomas are rare malignancies harbouring Hedgehog pathway alterations targetable by SMO antagonists (vismodegib/sonidegib). We describe, for the first time, the molecular genetics and response of a patient with Hedgehog inhibitor-resistant metastatic basal cell carcinoma who achieved rapid tumour regression (ongoing near complete remission at 4 months) with nivolumab (anti-PD1 antibody). He had multiple hallmarks of anti-PD1 responsiveness including high mutational burden (> 50 mutations per megabase; 19 functional alterations in tissue next-generation sequencing (NGS; 315 genes)) as well as PDL1/PDL2/JAK2 amplification (as determined by both tissue NGS and by analysis of plasma-derived cell-free DNA). The latter was performed using technology originally developed for the genome-wide detection of sub-chromosomal copy-number alterations (CNAs) in noninvasive prenatal testing and showed numerous CNAs including amplification of the 9p24.3-9p22.2 region containing PD-L1, PD-L2 and JAK2. Of interest, PD-L1, PD-L2 and JAK2 amplification is a characteristic of Hodgkin lymphoma, which is exquisitely sensitive to nivolumab. In conclusion, selected SMO antagonist-resistant metastatic basal cell carcinomas may respond to nivolumab based on underlying molecular genetic mechanisms that include PD-L1 amplification and high tumour mutational burden. PMID:27942391

  19. Facile synthesis of S-Ag nanocomposites and Ag2S short nanorods by the interaction of sulfur with AgNO3 in PEG400

    Science.gov (United States)

    Zhang, Yan-Li; Xie, Xin-Yuan; Liang, Ming; Xie, Shu-Ming; Chen, Jie-Mei; Zheng, Wen-Jie

    2016-06-01

    A facile, eco-friendly and inexpensive method to prepare Ag2S short nanorods and S-Ag nanocomposites using sublimed sulfur, AgNO3, PVP and PEG400 was studied. According to x-ray diffraction and scanning electron microscopy of the Ag2S, the products are highly crystalline and pure Ag2S nanorods with diameters of 70-160 nm and lengths of 200-360 nm. X-ray diffraction of the S-Ag nanocomposites shows that we obtained cubic Ag and S nanoparticles. Transmission electron microscopy shows that the molar ratio of PVP to Ag+ plays an important role in controlling the size and morphology of the S-Ag nanocomposites. When the molar ratio of PVP to Ag+ was 10:1, smaller sizes, better dispersibility and narrower distribution of S-Ag nanocomposites with diameters of 10-40 nm were obtained. The formation mechanism of the S-Ag nanocomposites was studied by designing a series of experiments using ultraviolet-visible measurement, and it was found that S nanoparticles are produced first and act as seed crystals; then Ag+ becomes Ag nanocrystals on the surfaces of the S nanoparticles by the reduction of PVP. PEG400 acts as a catalyzer, accelerating the reaction rate, and protects the S-Ag nanocomposites from reacting to produce Ag2S. The antimicrobial experiments show that the S-Ag nanocomposites have greater antimicrobial activity on Staphylococcus aureus, Aspergillus niger and blue mold than Ag nanoparticles.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-11-06

    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.

  1. Ag nanoprisms with Ag₂S attachment.

    KAUST Repository

    Xiong, Shenglin

    2013-01-01

    Triangular Ag nanoprisms are a type of most-studied noble-metal nanostructures over the past decade owing to their special structural architecture and outstanding optical and catalytic properties for a wide range of applications. Nevertheless, in contrast to active research for the synthesis of phase-pure Ag nanoprisms, no asymmetric heterodimers containing Ag prisms have been developed so far, probably due to lack of suitable synthetic methods. Herein, we devise a simple ion-exchange method to synthesize Ag2S/Ag heterodimers at room temperature, through which Ag nanoprisms with controllable size and thickness can be fabricated. Formation chemistry and optical properties of the heterodimers have been investigated. These semiconductor/metal heterodimers have exhibited remarkable bactericidal activity to E. coli cells under visible light illumination.

  2. A Study of Surfactant-Induced Growth of Ag on Ag (111)

    Institute of Scientific and Technical Information of China (English)

    WU Li-Li; HU Juan-Mei; WU Feng-Min

    2008-01-01

    A new growth model is introduced to describe surfactant-induced growth of Ag on Ag (111) with realistic physical parameters. In this model, the A-S exchange mechanism is considered for the first time. Using the Monte Carlo simulations, the influence of exchange mechanism, surface temperature T, the exchange barrier Eex, and the coverage of surfactant θM on the growth mode and morphology during multilayer film growth of Ag/Ag (111) are studied in detail. Both the referenced value of surfactant coverage and the method to obtain perfect layer-by-layer film in surfactant-induced Ag/Ag (111) system are provided. Our simulation results are consistent with many experimental observations for surfactant-induced growth of Ag on Ag (111).

  3. Hydrogen adsorption on bimetallic PdAu(111) surface alloys

    DEFF Research Database (Denmark)

    Takehiro, Naoki; Liu, Ping; Bergbreiter, Andreas

    2014-01-01

    The adsorption of hydrogen on structurally well defined PdAu-Pd(111) monolayer surface alloys was investigated in a combined experimental and theoretical study, aiming at a quantitative understanding of the adsorption and desorption properties of individual PdAu nanostructures. Combining...... the structural information obtained by high resolution scanning tunneling microscopy (STM), in particular on the abundance of specific adsorption ensembles at different Pd surface concentrations, with information on the adsorption properties derived from temperature programmed desorption (TPD) spectroscopy...... and high resolution electron energy loss spectroscopy (HREELS) provides conclusions on the minimum ensemble size for dissociative adsorption of hydrogen and on the adsorption energies on different sites active for adsorption. Density functional theory (DFT) based calculations give detailed insight...

  4. Formation of Au/Pd Alloy Nanoparticles on TMV

    Directory of Open Access Journals (Sweden)

    Jung-Sun Lim

    2010-01-01

    Full Text Available A gold-palladium (AuPd solid solution alloy was successfully deposited on the genetically engineered tobacco mosaic virus (TMV1Cys by the biosorption of Au(III and Pd(II precursors and the reduction of the Au(III and Pd(II to their respective metals or metal alloy. The resulting morphologies of alloy nanoparticles deposited on the TMV1Cys were observed with transmission electron microscopy (TEM, and the AuPd alloy formation was supported with surface plasmon resonance (SPR and selected area electron diffraction (SAED. In addition, selected alloy nanoparticles on the TMV1Cys were analyzed further with electron energy loss spectroscopy (EELS to confirm the presence of gold and palladium. Our result implies that biotemplated metal mineralization is a potentially useful methodology to prepare alloy nanoparticles.

  5. How Does Your Doctor Make a PD Diagnosis?

    Science.gov (United States)

    ... a table, called United Parkinson's Disease Rating Scale (UPDRS). UPDRS is a universal scale of PD symptoms and ... Movement Disorders Society for their version of the UPDRS. The response to medications (that imitate or stimulate ...

  6. Thermodynamic assessment of the Pd-H-D-T system

    Energy Technology Data Exchange (ETDEWEB)

    Joubert, J.-M., E-mail: jean-marc.joubert@icmpe.cnrs.f [Chimie Metallurgique des Terres Rares, Institut de Chimie et des Materiaux Paris-Est, CNRS, Universite de Paris XII, UMR 7182, 2-8 rue Henri Dunant, F-94320 Thiais (France); Thiebaut, S. [CEA/DAM/Valduc, F-21120 Is sur Tille (France)

    2009-12-15

    The three binary systems H-Pd, D-Pd and Pd-T have been modelled in the frame of the Calphad approach. A complete literature search has been undertaken and the most significant experimental data have been selected for a thermodynamic assessment of these systems. To complement the available data, pressure-composition curves have been measured for the three systems in the present work. The three systems are characterized by a strong isotope effect which is well taken into account in the modelling. They have been combined to perform calculations in the quaternary H-D-Pd-T system. It is shown that a reasonable extrapolation can be made without the use of ternary parameters if it is calculated with the so-called Toop model.

  7. Structural and magnetic properties of granular CoPd multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Vivas, L.G.; Figueroa, A.I.; Bartolomé, F. [Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC-Universidad de Zaragoza, Dept. de Física de la Materia Condensada, E-50009 Zaragoza (Spain); Rubín, J. [Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC-Universidad de Zaragoza, Dept. de Ciencia y Tecnología de Materiales y Fluidos, E-50018 Zaragoza (Spain); García, L.M. [Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC-Universidad de Zaragoza, Dept. de Física de la Materia Condensada, E-50009 Zaragoza (Spain); Deranlot, C.; Petroff, F. [Unité Mixte de Physique CNRS/Thales, F-91767 Palaiseau Cedex, France and Université Paris-Sud, F-191405 Orsay Cedex (France); Ruiz, L.; González-Calbet, J.M [Dept. de Química Inorgánica, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Brookes, N.B.; Wilhelm, F.; Rogalev, A. [European Synchrotron Radiation Facility (ESRF), CS40220, F-38043 Grenoble Cedex 9 (France); Bartolomé, J. [Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC-Universidad de Zaragoza, Dept. de Física de la Materia Condensada, E-50009 Zaragoza (Spain)

    2016-02-15

    Multilayers of bimetallic CoPd alloyed and assembled nanoparticles, prepared by room temperature sequential sputtering deposition on amorphous alumina, were studied by means of high-resolution transmission electron microscopy, x-ray diffraction, SQUID-based magnetometry and x-ray magnetic circular dichroism. Alloying between Co and Pd in these nanoparticles gives rise to a high perpendicular magnetic anisotropy. Their magnetic properties are temperature dependent: at low temperature, the multilayers are ferromagnetic with a high coercive field; at intermediate temperature the behavior is of a soft-ferromagnet, and at higher temperature, the perpendicular magnetic anisotropy in the nanoparticles disappears. The magnetic orbital moment to spin moment ratio is enhanced compared with Co bare nanoparticles and Co fcc bulk. - Highlights: • CoPd granular nanolayers show perpendicular magnetic anisotropy. • Three magnetic phases are detected: hard-ferro, soft-ferro and superparamagnetism. • The nanoparticles have Co-core and CoPd alloy shell morphology.

  8. Transplantation outcome in patients on PD and HD.

    Science.gov (United States)

    Cancarini, Giovanni C; Sandrini, Silvio; Setti, Gisella; Bossini, Nicola; Cassamali, Silvia; Pertica, Nicoletta; Maiorca, Paolo

    2006-01-01

    In the past, peritoneal dialysis (PD) has been considered a second choice dialysis modality for many aspects and that negative attitude has been extended also to possible negative effects on renal transplantation. In the last years, many papers have faced the question whether PD could attain similar results in renal transplantation as hemodialysis and there is sufficient evidence to answer that question. On the short time after transplantation, patients coming PD have lower prevalence of delayed graft function than hemodialysis patients, but higher prevalence of renal vascular thrombosis, above all in children. Incidence of acute graft rejection is not different between the two dialysis modalities. The long-term outcome of renal transplantation is similar in patients coming from either PD or hemodialysis.

  9. CoTaZr/Pd multilayer with perpendicular magnetic anisotropy

    Directory of Open Access Journals (Sweden)

    Yong Chang Lau

    2013-08-01

    Full Text Available We report a novel perpendicularly magnetized thin film [Co91.5Ta4.5Zr4/Pd]5 multilayer, which exhibits strong perpendicular magnetic anisotropy when grown on 5 nm of Pd and Ru seed layers. The Pd-seeded multilayer annealed at 300 °C shows an effective uniaxial anisotropy constant, Keff = 1.1 MJ m−3, with an anisotropy field as high as 1.6 T. The perpendicular anisotropy is sustained on annealing at 400 °C for 1 h. X-ray diffraction on multilayers with 30 repeats suggests that the use of amorphous CoTaZr reduces the stress of the stack, compared to [Co/Pd] multilayer.

  10. Evaluation for n+108Pd below 20 MeV

    Institute of Scientific and Technical Information of China (English)

    QIAN; Jing

    2015-01-01

    The 108Pd cross section for neutron-induced reactions plays a very important role in reactor shielding calculation.In this work,existing experimental data and evaluation data(ENDF/B-Ⅶ.1,4.0,CENDL JENDL-4.0,JEFF-3.1)for 108Pd were collected.The main cross section of neutron incident reaction,the discrete energy

  11. Transformation from Ag@Ag3PO4 to Ag@Ag2SO4 hybrid at room temperature: preparation and its visible light photocatalytic activity

    Science.gov (United States)

    Wei, Ting; Gao, Shanmin; Wang, Qingyao; Xu, Hui; Wang, Zeyan; Huang, Baibiao; Dai, Ying

    2017-02-01

    In the present study, Ag/Ag2SO4 hybrid photocatalysts were obtained via a facile redox-precipitation reaction approach by using Ag@Ag3PO4 nanocomposite as the precursor and KMnO4 as the oxidant. Multiple techniques, such as X-ray diffraction pattern (XRD), transmission electron microscope (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS) and Brunauer-Emmett-Teller (BET), photocurrent and electrochemical impedance spectroscopy (EIS), were applied to investigate the structures, morphologies, optical, and electronic properties of as-prepared samples. The photocatalytic activities were evaluated by photodegradation of organic rhodamine B (RhB) and methyl orange (MO) under visible light irradiation. It was found that pure Ag2SO4 can partially transform into metallic Ag during the photocatalytic degradation of organic pollutants, but the Ag/Ag2SO4 hybrids can maintain its structure stability and show enhanced visible light photocatalytic activity because of the surface plasma resonance effect of the metallic Ag.

  12. Multiple Partial Siberian Snakes in the AGS

    Science.gov (United States)

    Takano, J.; Ahrens, L. A.; Bai, M.; Brown, K.; Courant, E. D.; Gardner, C. J.; Glenn, J. W.; Hattori, T.; Huang, H.; Lin, F.; Luccio, A. U.; MacKay, W. W.; Okamura, M.; Roser, T.; Tepikian, S.; Tsoupas, N.; Yip, K.; Zelenski, A.; Zeno, K.

    2007-06-01

    Polarized protons are accelerated up to 24.3 GeV in the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL). To accelerate the beam with preserving the polarization, two different types of helical dipole partial Siberian snake have been installed to the AGS. One is a superconducting magnet (Cold Snake, CSNK), and the other is a normal conducting one (Warm Snake, WSNK). With these snake magnets, the polarization at the AGS extraction achieved 65%. However, the AGS has spin mismatches at the injection and extraction. This description shows calculated results to have better spin matching with using two or three snakes.

  13. High-performance PdRu bimetallic catalyst supported on mesoporous silica nanoparticles for phenol hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chao [The Key Laboratory of Fuel Cell Technology of Guangdong Province and The Key Laboratory for New Energy of Guangdong Universities, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou (China); Yang, Xu [Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou (China); Yang, Hui; Huang, Peiyan; Song, Huiyu [The Key Laboratory of Fuel Cell Technology of Guangdong Province and The Key Laboratory for New Energy of Guangdong Universities, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou (China); Liao, Shijun, E-mail: chsjliao@scut.edu.cn [The Key Laboratory of Fuel Cell Technology of Guangdong Province and The Key Laboratory for New Energy of Guangdong Universities, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou (China)

    2014-10-01

    Graphical abstract: The addition of Ru could significantly improve the performance of the mesoporous silica nanoparticles supported PdRu/MSN catalyst, which showed over 5 times higher mass activity than the mono-Pd/MSN towards the liquid-phase hydrogenation of phenol. The improved dispersion and the electronic interaction contributed to the enhanced catalytic activity for the catalyst towards phenol hydrogenation. - Highlights: • PdRu bimetal catalyst supported on mesoporous silica nanoparticles was prepared. • The average sizeof PdRu alloy is smaller than that of mono-Pd. • The addition of Ru to Pd modulates the electronic properties between Pd and Ru. • PdRu/MSN catalyst shows superior activity on phenol hydrogenation than Pd/MSN. • PdRu/MSN catalyst shows good selectivity for cyclohexanol to some extent. - Abstract: A high-performance PdRu bimetallic catalyst supported on mesoporous silica nanoparticles (MSN), PdRu/MSN, was prepared by a facile impregnation–hydrogen reduction method. It was found that PdRu/MSN showed 5 times higher activity than that of Pd/MSN towards the liquid-phase hydrogenation of phenol. The catalysts were characterized comprehensively by multiple techniques, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and hydrogen temperature program reduction (TPR). It was revealed that adding Ru could effectively improve the Pd dispersion and promote the electronic interaction between the Pd and Ru, both of which contribute to enhancing the catalytic activity.

  14. Manipulating the optical properties of symmetrically branched Au/Pd nanocrystals through interior design.

    Science.gov (United States)

    DeSantis, Christopher J; Skrabalak, Sara E

    2014-05-25

    Au/Pd octopods with hollow, cubic interiors and Oh symmetry were synthesized for the first time by etching core@shell Pd@Au/Pd octopods to selectively remove their Pd interiors. Integration of multiple architectural features - in this case branching symmetry, composition, and interior design - into one nanostructure provides design strategies to new plasmonic colloids.

  15. Highly efficient visible light plasmonic photocatalyst Ag@Ag(Br,I).

    Science.gov (United States)

    Wang, Peng; Huang, Baibiao; Zhang, Qianqian; Zhang, Xiaoyang; Qin, Xiaoyan; Dai, Ying; Zhan, Jie; Yu, Jiaoxian; Liu, Haixia; Lou, Zaizhu

    2010-09-03

    The new plasmonic photocatalyst Ag@Ag(Br,I) was synthesized by the ion-exchange process between the silver bromide and potassium iodide, then by reducing some Ag(+) ions in the surface region of Ag(Br,I) particles to Ag(0) species. Ag nanoparticles are formed from Ag(Br,I) by the light-induced chemical reduction reaction. The Ag@Ag(Br,I) particles have irregular shapes with their sizes varying from 83 nm to 1 mum. The as-grown plasmonic photocatalyst shows strong absorption in the visible light region because of the plasmon resonance of Ag nanoparticles. The ability of this compound to reduce Cr(VI) under visible light was compared with those of other reference photocatalyst. The plasmonic photocatalyst is shown to be highly efficient under visible light. The stability of the photocatalyst was examined by X-ray diffraction and X-ray photoelectron spectroscopy. The XRD pattern and XPS spectra prove the stability of the plasmonic photocatalyst Ag@Ag(Br,I).

  16. Hydrogen sorption in Pd monolayers in alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Martin, M.H. [Departement de chimie, Universite de Sherbrooke, 2500 blvd. de l' Universite, Sherbrooke, Quebec, J1K 2R1 (Canada); Lasia, A. [Departement de chimie, Universite de Sherbrooke, 2500 blvd. de l' Universite, Sherbrooke, Quebec, J1K 2R1 (Canada)], E-mail: a.lasia@usherbrooke.ca

    2009-09-01

    Hydrogen adsorption/absorption at palladium monolayers (ML) deposited on monocrystalline Au(1 1 1) electrode was studied in 0.1 M NaOH solution. H charge isotherms demonstrated that adsorption started at potentials more positive than at thicker nanometric Pd/Au(polycrystal) deposits. Due to 3-dimensional deposit growth, absorption could be seen at all deposits thicker than 1 ML. Besides, H sorption at Pd/Au(1 1 1) monolayers was more reversible than at nanometric Pd/Au(polycrystal) deposits. Strong geometric and electronic effects due to the Au substrate were observed up to 5 Pd ML. Influence of benzotriazole (BTA) on H sorption was also investigated. BTA blocked H adsorption above 250 mV vs. RHE. At less positive potentials adsorbed BTA layer seemed to undergo a reorientation allowing H adsorption. Stationary and dynamic electrochemical impedance spectroscopy was used to obtain double layer capacitance and charge transfer resistance. BTA also promoted kinetically H sorption into Pd/Au(1 1 1) monolayer and Pd/Au(polycrystal) nanometric deposits.

  17. Aromatization of n-octane over Pd/C catalysts

    KAUST Repository

    Yin, Mengchen

    2013-01-01

    Gas-phase aromatization of n-octane was investigated using Pd/C catalyst. The objectives were to: (1) determine the effects of temperature (400-600 °C), weight hourly space velocity (WHSV) (0.8-∞), and hydrogen to hydrocarbon molar ratio (MR) (0-6) on conversion, selectivity, and yield (2) compare the activity of Pd/C with Pt/C and Pt/KL catalysts and (3) test the suitability of Pd/C for aromatization of different alkanes including n-hexane, n-heptane, and n-octane. Pd/C exhibited the best aromatization performance, including 54.4% conversion and 31.5% aromatics yield at 500 °C, WHSV = 2 h-1, and a MR of 2. The Pd/C catalyst had higher selectivity towards the preferred aromatics including ethylbenzene and xylenes, whereas Pt/KL had higher selectivity towards benzene and toluene. The results were somewhat consistent with adsorbed n-octane cyclization proceeding mainly through the six-membered ring closure mechanism. In addition, Pd/C was also capable of catalyzing aromatization of n-hexane and n-heptane. © 2012 Elsevier Ltd. All rights reserved.

  18. Phylogenetic diversity (PD and biodiversity conservation: some bioinformatics challenges

    Directory of Open Access Journals (Sweden)

    Daniel P. Faith

    2006-01-01

    Full Text Available Biodiversity conservation addresses information challenges through estimations encapsulated in measures of diversity. A quantitative measure of phylogenetic diversity, “PD”, has been defined as the minimum total length of all the phylogenetic branches required to span a given set of taxa on the phylogenetic tree (Faith 1992a. While a recent paper incorrectly characterizes PD as not including information about deeper phylogenetic branches, PD applications over the past decade document the proper incorporation of shared deep branches when assessing the total PD of a set of taxa. Current PD applications to macroinvertebrate taxa in streams of New South Wales, Australia illustrate the practical importance of this definition. Phylogenetic lineages, often corresponding to new, “cryptic”, taxa, are restricted to a small number of stream localities. A recent case of human impact causing loss of taxa in one locality implies a higher PD value for another locality, because it now uniquely represents a deeper branch. This molecular-based phylogenetic pattern supports the use of DNA barcoding programs for biodiversity conservation planning. Here, PD assessments side-step the contentious use of barcoding-based “species” designations. Bio-informatics challenges include combining different phylogenetic evidence, optimization problems for conservation planning, and effective integration of phylogenetic information with environmental and socio-economic data.

  19. Atomistic modeling of H absorption in Pd nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ruda, M., E-mail: ruda@cab.cnea.gov.a [Centro Atomico Bariloche, 8400 Bariloche (Argentina); Centro Regional Universitario Bariloche, U.N. Comahue (Argentina); Crespo, E.A., E-mail: crespo@uncoma.edu.a [Depto. de Fisica, Fac. de Ingenieria, Universidad Nacional del Comahue, Buenos Aires 1400, 8300 Neuquen (Argentina); Debiaggi, S. Ramos de, E-mail: ramos@uncoma.edu.a [Depto. de Fisica, Fac. de Ingenieria, Universidad Nacional del Comahue, Buenos Aires 1400, 8300 Neuquen (Argentina); CONICET (Argentina)

    2010-04-16

    Size affects the properties of absorption of H in Palladium nanoparticles. Because of their higher proportion of surface atoms compared to the bulk, the pressure-composition (P-C) isotherms of the nanoparticles are modified. We performed atomistic simulations for different-sized Pd nanoparticles and for the bulk at different H concentrations using the Monte Carlo technique in the TP{mu}N ensemble to calculate the P-C isotherms. The Pd-H interatomic potentials are of the Embedded Atom (EAM) type and have been recently developed by Zhou et al. . From the related van't Hoff equation we obtained |{Delta}H{sup o}| = (28 {+-} 7) kJ/0.5 mol of H{sub 2} and |{Delta}S{sup o}| = (71 {+-} 19) J/0.5 mol of H{sub 2}.K for the PdH formation in the bulk. For Pd nanoparticles previous simulations results based on a different set of EAM potentials showed that H was absorbed primarily in the surface before diffusing into the inside of small Pd clusters . Considering the better performance of Zhou's potentials for the bulk, in this work we analyzed the evolution of the equilibrium microstructure of Pd nanoparticles as a function of their size and H concentration. Our simulations predict enhanced hydrogen solubilities and vanishing plateaux when compared to the bulk and that H is absorbed in the subsurface of the nanoparticles.

  20. Soluble Programmed Death 1 (PD-1) Is Decreased in Patients With Immune Thrombocytopenia (ITP): Potential Involvement of PD-1 Pathway in ITP Immunopathogenesis.

    Science.gov (United States)

    Birtas Atesoglu, Elif; Tarkun, Pinar; Demirsoy, Esra Terzi; Geduk, Ayfer; Mehtap, Ozgur; Batman, Adnan; Kaya, Fatih; Cekmen, Mustafa Baki; Gulbas, Zafer; Hacıhanefioglu, Abdullah

    2016-04-01

    Immune thrombocytopenia (ITP) is an autoimmune disease characterized by dysregulation of T cells. Programmed death (PD) 1 and programmed death 1 ligand 1 (PD-L1) are cosignaling molecules, and the major role of the PD-1 pathway is the inhibition of self-reactive T cells and to protect against autoimmune diseases. We measured levels of serum soluble PD 1 (sPD-1) and serum soluble PD-L1 (sPD-L1) in 67 patients with ITP (24 newly diagnosed ITP [ndITP], 43 chronic ITP [cITP]) and 21 healthy controls (HCs). We determined decreased serum sPD-1 levels both in patients with ndITP and in patients with cITP when compared to HC. Moreover, there was a positive correlation between sPD-1 levels and platelet counts. The sPD-L1 levels were decreased in patients with ndITP when compared to patients with cITP. This is the first study investigating PD-1 signaling pathway in ITP. Decreased sPD-1 levels may have a role in ITP pathogenesis as without the inhibitory regulation of PD-1, sustained activation of T cells may cause inflammatory responses which is the case in ITP.

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

    Energy Technology Data Exchange (ETDEWEB)

    Unal, Baris [Iowa State Univ., Ames, IA (United States)

    2008-01-01

    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

  2. Structure and Mobility of Metal Clusters in MOFs: Au, Pd, and AuPd Clusters in MOF-74

    DEFF Research Database (Denmark)

    Vilhelmsen, Lasse; Walton, Krista S.; Sholl, David S.

    2012-01-01

    functional theory (DFT) calculations with a genetic algorithm (GA) to reliably predict the structure of the adsorbed clusters. This approach allows comparison of hundreds of adsorbed configurations for each cluster. From the investigation of Au8, Pd8, and Au4Pd4 we find that the organic part of the MOF......Understanding the adsorption and mobility of metal–organic framework (MOF)-supported metal nanoclusters is critical to the development of these catalytic materials. We present the first theoretical investigation of Au-, Pd-, and AuPd-supported clusters in a MOF, namely MOF-74. We combine density...... is just as important for nanocluster adsorption as open Zn or Mg metal sites. Using the large number of clusters generated by the GA, we developed a systematic method for predicting the mobility of adsorbed clusters. Through the investigation of diffusion paths a relationship between the cluster’s...

  3. Ab initio studies on the mechanic and magnetic properties of PdHx

    Institute of Scientific and Technical Information of China (English)

    Cui Xin; Liang Xi-Xia; Wang Jian-Tao; Zhao Guo-Zhong

    2011-01-01

    Based on ab initio total energy calculations, the structural, electronic, mechanic, and magnetic properties of PdHx are investigated. It is found that bulk modulus of PdHx is larger than the metal Pd with the hydrogen storage except Pd4H2. The calculated results for the magnetic moments show that the hydrogen addition weakens the magnetic properties of the PdHx systems. A strong magneto-volume effect is found in PdHx structures as well as Pd. The transition from paramagnetism to ferromagnetism is discussed. The corresponding densities of states for both structures are also shown to understand the magnetic behaviour.

  4. Enhancement in anomalous Hall resistivity of Co/Pd multilayer and CoPd alloy by Ga+ ion irradiation

    KAUST Repository

    Guo, Zaibing

    2014-02-01

    In this paper, we report the effect of Ga+ ion irradiation on anomalous Hall effect (AHE) and longitudinal resistivity (ρxx) in [Co(3 Å)/Pd(5 Å)]80 multilayer and Co 42Pd58 alloy. 4- and 2-fold increases in anomalous Hall resistivity (ρAH) in the Co/Pd multilayer and CoPd alloy have been observed after irradiations at doses of 2.4 × 1015 and 3.3×10 15 ions/cm2, respectively. Skew scattering and side jump contributions to AHE have been analyzed based on the scaling relationship ρAH = aρxx + bρ2xx. For the Co/Pd multilayer, AHE is mainly affected by ion irradiation-induced interface diffusion and defects. For the CoPd alloy, the increase in doses above 1.5 × 1015 ions/cm2 induces a sign change in skew scattering, followed by the skew scattering contribution to AHE overwhelming the side jump contribution, this phenomenon should be attributed to irradiation-induced defects and modifications in chemical ordering. © Copyright EPLA, 2014.

  5. Enhancement in anomalous Hall resistivity of Co/Pd multilayer and CoPd alloy by Ga+ ion irradiation

    Science.gov (United States)

    Guo, Z. B.; Mi, W. B.; Li, J. Q.; Cheng, Y. C.; Zhang, X. X.

    2014-02-01

    In this paper, we report the effect of Ga+ ion irradiation on anomalous Hall effect (AHE) and longitudinal resistivity (\\rho_{\\textit{xx}}) in [Co(3 Å)/Pd(5 Å)]80 multilayer and Co42Pd58 alloy. 4- and 2-fold increases in anomalous Hall resistivity (\\rho_{\\textit{AH}}) in the Co/Pd multilayer and CoPd alloy have been observed after irradiations at doses of 2.4\\times 10^{15} and 3.3\\times 10^{15}\\ \\text{ions/cm}^{2} , respectively. Skew scattering and side jump contributions to AHE have been analyzed based on the scaling relationship \\rho_{\\textit{AH}}=a\\rho_{\\textit{xx}}+b\\rho_{\\textit{xx}}^{2} . For the Co/Pd multilayer, AHE is mainly affected by ion irradiation-induced interface diffusion and defects. For the CoPd alloy, the increase in doses above 1.5\\times 10^{15}\\ \\text{ions/cm}^{2} induces a sign change in skew scattering, followed by the skew scattering contribution to AHE overwhelming the side jump contribution, this phenomenon should be attributed to irradiation-induced defects and modifications in chemical ordering.

  6. Sb Surface Modification of Pd by Mimetic Underpotential Deposition for Formic Acid Oxidation

    OpenAIRE

    Long-Long Wang; Xiao-Lu Cao; Ya-Jun Wang; Qiao-Xia Li

    2015-01-01

    The newly proposed mimetic underpotential deposition (MUPD) technique was extended to modify Pd surfaces with Sb through immersing a Pd film electrode or dispersing Pd/C powder in a Sb(III)-containing solution blended with ascorbic acid (AA). The introduction of AA shifts down the open circuit potential of Pd substrate available to achieve suitable Sb modification. The electrocatalytic activity and long-term stability towards HCOOH electrooxidation of the Sb modified Pd surfaces (film elect...

  7. Submonolayered Ru Deposited on Ultrathin Pd Nanosheets used for Enhanced Catalytic Applications.

    Science.gov (United States)

    Zhang, Zhicheng; Liu, Ye; Chen, Bo; Gong, Yue; Gu, Lin; Fan, Zhanxi; Yang, Nailiang; Lai, Zhuangchai; Chen, Ye; Wang, Jie; Huang, Ying; Sindoro, Melinda; Niu, Wenxin; Li, Bing; Zong, Yun; Yang, Yanhui; Huang, Xiao; Huo, Fengwei; Huang, Wei; Zhang, Hua

    2016-12-01

    Ultrathin Pd nanosheets (NSs) coated with submonolayered Ru, referred to as Pd@Ru NSs, are synthesized via a seed-mediated growth method. The underpotential deposition can be the driving force for the formation of Pd@Ru NSs. The Pd@Ru NSs exhibit superior catalytic properties in the reduction of 4-nitrophenol and the semihydrogenation of 1-octyne, compared to the pure Pd NSs and Ru NSs.

  8. Visible light driven photocatalysis and antibacterial activity of AgVO{sub 3} and Ag/AgVO{sub 3} nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Anamika [Department of Life Sciences, University of Mumbai, Santacruz (E), Mumbai 400 098 (India); Dutta, Dimple P., E-mail: dimpled@barc.gov.in [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Ballal, A. [Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Tyagi, A.K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Fulekar, M.H. [School of Environment and Sustainable Development, Central University of Gujarat, Gandhinagar 382 030, Gujarat (India)

    2014-03-01

    Graphical abstract: - Highlights: • Ag/AgVO{sub 3} and pure AgVO{sub 3} nanowires synthesized by sonochemical process. • Characterization done using XRD, SEM, TEM, EDX and BET analysis. • Visible light degradation of RhB by Ag/AgVO{sub 3} within 45 min. • Antibacterial activity of Ag/AgVO{sub 3} demonstrated. - Abstract: Ag/AgVO{sub 3} nanowires and AgVO{sub 3} nanorods were synthesized in aqueous media via a facile sonochemical route. The as-synthesized products were characterized by X-ray diffraction, Brunauer–Emmett–Teller surface area analysis, scanning electron microscopy together with an energy dispersion X-ray spectrum analysis, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy. The results revealed that inert atmosphere promotes the formation of Ag/AgVO{sub 3} nanowires. The photocatalytic studies revealed that the Ag/AgVO{sub 3} nanowires exhibited complete photocatalytic degradation of Rhodamine B within 45 min under visible light irradiation. The antibacterial activity of Ag/AgVO{sub 3} nanowires was tested against Escherechia coli and Bacillus subtilis. The minimum growth inhibitory concentration value was found to be 50 and 10 folds lower than for the antibiotic ciprofloxacin for E. coli and B. subtilis, respectively. The antibacterial properties of the β-AgVO{sub 3} nanorods prove that in case of the Ag dispersed Ag/AgVO{sub 3} nanowires, the enhanced antibacterial action is also due to contribution from the AgVO{sub 3} support.

  9. Effects of soil and dietary exposures to Ag nanoparticles and AgNO₃ in the terrestrial isopod Porcellionides pruinosus.

    Science.gov (United States)

    Tourinho, Paula S; van Gestel, Cornelis A M; Jurkschat, Kerstin; Soares, Amadeu M V M; Loureiro, Susana

    2015-10-01

    The effects of Ag-NPs and AgNO3 on the isopod Porcellionides pruinosus were determined upon soil and dietary exposures. Isopods avoided Ag in soil, with EC50 values of ∼16.0 and 14.0 mg Ag/kg for Ag-NPs and AgNO3, respectively. Feeding inhibition tests in soil showed EC50s for effects on consumption ratio of 127 and 56.7 mg Ag/kg, respectively. Although similar EC50s for effects on biomass were observed for nanoparticulate and ionic Ag (114 and 120 mg Ag/kg dry soil, respectively), at higher concentrations greater biomass loss was found for AgNO3. Upon dietary exposure, AgNO3 was more toxic, with EC50 for effects on biomass change being >1500 and 233 mg Ag/kg for Ag-NPs and AgNO3, respectively. The difference in toxicity between Ag-NPs and AgNO3 could not be explained from Ag body concentrations. This suggests that the relation between toxicity and bioavailability of Ag-NPs differs from that of ionic Ag in soils.

  10. Kinetics of Ag-rich precipitates formation in Cu-Al-Ag alloys

    Energy Technology Data Exchange (ETDEWEB)

    Adorno, A.T.; Guerreiro, M.R.; Silva, R.A.G

    2004-06-15

    The kinetics of Ag-rich precipitates formation in the Cu-2 wt.% Al alloy with additions of 2, 4, 6, 8, 10 and 12 wt.% Ag was studied using microhardness changes with temperature and time, differential scanning calorimetry (DSC), differential thermal analysis (DTA), scanning electron microscopy (SEM), optical microscopy (OM), energy dispersive X-ray analysis (EDX) and X-ray diffractometry (XRD). The results indicated that an increase in the Ag content decreases the activation energy for Ag-rich precipitates formation, and that it is possible to estimate the values of the diffusion and nucleation activation energies for the Ag precipitates.

  11. Photocatalytic oxidation removal of Hg0 using ternary Ag/AgI-Ag2CO3 hybrids in wet scrubbing process under fluorescent light

    Science.gov (United States)

    Zhang, Anchao; Zhang, Lixiang; Chen, Xiaozhuan; Zhu, Qifeng; Liu, Zhichao; Xiang, Jun

    2017-01-01

    A series of ternary Ag/AgI-Ag2CO3 photocatalysts synthesized using a facile coprecipitation method were employed to investigate their performances of Hg0 removal in a wet scrubbing reactor. The hybrids were characterized by N2 adsorption-desorption, XRD, SEM-EDS, HRTEM, XPS, DRS and ESR. The photocatalytic activities of Hg0 removal were evaluated under fluorescent light. The results showed that AgI content, fluorescent light irradiation, reaction temperature all showed significant influences on Hg0 removal. NO exhibited significant effect on Hg0 removal in comparison to SO2. Among these ternary Ag/AgI-Ag2CO3 hybrids, Ag/AgI(0.1)-Ag2CO3 showed the highest Hg0 removal efficiency, which could be ascribed to the effective separation of photogenerated electron-hole pairs between AgI and Ag2CO3 and the surface plasmon resonance (SPR) effect in the visible region by metallic silver nanoparticles (Ag0 NPs). The trapping studies of reactive radicals showed that the superoxide radicals (rad O2-) may play a key role in Hg0 removal under fluorescent light. According to the experimental and characterization results, a possible photocatalytic oxidation mechanism for enhanced Hg0 removal over Ag/AgI(0.1)-Ag2CO3 hybrid under fluorescent light was proposed.

  12. Numerical Prediction of the Thermodynamic Properties of Ternary Al-Ni-Pd Alloys

    Science.gov (United States)

    Zagula-Yavorska, Maryana; Romanowska, Jolanta; Kotowski, Sławomir; Sieniawski, Jan

    2016-01-01

    Thermodynamic properties of ternary Al-Ni-Pd system, such as exGAlNPd, µAl(AlNiPd), µNi(AlNiPd) and µPd(AlNiPd) at 1,373 K, were predicted on the basis of thermodynamic properties of binary systems included in the investigated ternary system. The idea of predicting exGAlNiPd values was regarded as calculation of values of the exG function inside a certain area (a Gibbs triangle) unless all boundary conditions, that is values of exG on all legs of the triangle are known (exGAlNi, exGAlPd, exGNiPd). This approach is contrary to finding a function value outside a certain area, if the function value inside this area is known. exG and LAl,Ni,Pd ternary interaction parameters in the Muggianu extension of the Redlich-Kister formalism were calculated numerically using the Excel program and Solver. The accepted values of the third component xx differed from 0.01 to 0.1 mole fraction. Values of LAlNiPd parameters in the Redlich-Kister formula are different for different xx values, but values of thermodynamic functions: exGAlNiPd, µAl(AlNiPd), µNi(AlNiPd) and µPd(AlNiPd) do not differ significantly for different xx values. The choice of xx value does not influence the accuracy of calculations.

  13. Growth of Ag nanocrystals on multiwalled carbon nanotubes and Ag-carbon nanotube interaction

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The experimental investigations on the interaction between Ag-nanocrystal particles (Ag-NCPs) and carbon nanotubes (CNTs) in Ag-nanocrystal particles/carbon nanotubes (Ag-NCPs/CNTs) hybrid structures were reported. The growth of Ag-NCPs on multiwalled carbon nanotubes (MWCNTs) was carried out by thermal evaporation deposition. High-resolution transmission electron microscopy and X-ray diffraction analyses revealed that Ag-NCPs had the crystal lattice feature of face-centered cube (fcc). The growth of Ag-NCPs on MWCNTs induced the cross-section deformation of MWCNT. The experimental results also showed that the synthesized Ag-NCPs/CNTs hybrid structure appeared as quasi-one dimensional nanowires containing the Ag-NCP/CNT hetero-junction. There was local cross-section deformation on MWCNTs at the interface of hetero-junction. These results involve the important topic about fundamental and practical studies for structure of MNCPs on CNTs and also find clues to further research of Ag nanocrystal growing on MWCNTs and related Ag-CNT interaction.

  14. Strain distributions of confined Au/Ag and Ag/Au nanoparticles

    Institute of Scientific and Technical Information of China (English)

    黄红华; 章英; 刘晓山; 骆兴芳; 袁彩雷; 叶双莉

    2015-01-01

    The strain distributions of Au/Ag and Ag/Au nanoparticles confined in the Al2O3 matrix with different core sizes are investigated by using the finite element method, respectively. The simulation results clearly indicate that the compressive strains exerted on the Au/Ag and Ag/Au nanoparticles can be induced by the Al2O3 matrix. Moreover, it can be found that the strain gradient existing in a Au/Ag nanoparticle is much larger than that in a Ag/Au nanoparticle, which could be due to the larger Young’s modulus of Au than that of Ag. With the core size increasing, the strain gradient existing in the Au/Ag nanoparticle becomes larger, while the strain gradient existing in the Ag/Au nanoparticle keeps constant. These different strain distributions may have significant infl uences on the structures and morphologies of the Au/Ag and Ag/Au nanoparticles, leading to the different physical properties for potential applications.

  15. Label-Free Detection of Ag+ Based on Gold Nanoparticles and Ag+-Specific DNA.

    Science.gov (United States)

    Pu, Wendan; Zhao, Zhao; Wu, Liping; Liu, Yue; Zhao, Huawen

    2015-08-01

    A sensitive label-free method was presented for the determination of silver ion (Ag+) in this paper. Cytosine-rich DNA (C-DNA) was used as Ag+ specific DNA. Without Ag+ in the solution, fluorescence of fluorescein (FAM) is quenched by C-DNA stabilized gold nanoparticles (AuNPs) in high salt environment. When Ag+ is present in the solution, however, Ag+-mediated cytosine-Ag+-cytosine (C-Ag+-C) base pairs induced the C-DNA folding into a hairpin structure, which can not stabilize AuNPs in high salt environment, thus causing AuNPs aggregation. After centrifugation to remove the aggregated AuNPs, the quenching ability of the supernatant for FAM is decreased and the fluorescence intensity of solution increases with increasing the Ag+ concentration. Due to the highly specific interaction of the C-DNA towards Ag+ and the strong fluorescent quenching ability of AuNPs for FAM, the method has high selectivity and sensitivity for Ag+. Under the optimal conditions, the fluorescence intensity at 515 nm increased linearly with the concentration of Ag+ ranging from 15 nM to 700 nM, and the detection limit was determined as 6 nM based on 3 σ/slope. This method is simple, sensitive, and may be applied to other detection systems by selecting the appropriate DNA sequences.

  16. Au, Ag and Au:Ag colloidal nanoparticles synthesized by pulsed laser ablation as SERS substrates

    Directory of Open Access Journals (Sweden)

    M. Vinod

    2014-12-01

    Full Text Available Chemically pure colloidal suspensions of gold and silver nanoparticles were synthesized using pulsed laser ablation. The dependence of laser fluence on the surface plasmon characteristics of the nanoparticles was investigated. Au:Ag colloidal suspensions were prepared by mixing highly monodisperse Au and Ag nanocolloids. The plasmon band of these mixtures was found to be highly sensitive to Au:Ag concentration ratio and wavelength of the laser beam used in the ablation process. The Au:Ag mixture consists of almost spherical shaped nanostructures with a tendency to join with adjacent ones. The surface enhanced Raman scattering activity of the Au, Ag and Au:Ag colloidal suspensions was tested using crystal violet as probe molecules. Enhancement in Raman signal obtained with Au:Ag substrates was found to be promising and strongly depends on its plasmon characteristics.

  17. Au, Ag and Au:Ag colloidal nanoparticles synthesized by pulsed laser ablation as SERS substrates

    Institute of Scientific and Technical Information of China (English)

    M. Vinod; K.G.Gopchandran

    2014-01-01

    Chemically pure colloidal suspensions of gold and silver nanoparticles were synthesized using pulsed laser ablation. The dependence of laser fluence on the surface plasmon characteristics of the nanoparticles was investigated. Au:Ag colloidal suspensions were prepared by mixing highly monodisperse Au and Ag nanocolloids. The plasmon band of these mixtures was found to be highly sensitive to Au:Ag concentration ratio and wavelength of the laser beam used in the ablation process. The Au:Ag mixture consists of almost spherical shaped nanostructures with a tendency to join with adjacent ones. The surface enhanced Raman scattering activity of the Au, Ag and Au:Ag colloidal suspensions was tested using crystal violet as probe molecules. Enhancement in Raman signal obtained with Au:Ag substrates was found to be promising and strongly depends on its plasmon characteristics.

  18. Identification of Ag-acceptor related photoluminescence in $^{111}\\!$Ag doped CdTe

    CERN Document Server

    Hamann, J; Deicher, M; Filz, T; Ostheimer, V; Schmitz, C; Wolf, H; Wichert, T

    1998-01-01

    Bridgman-grown, nominally undoped CdTe crystals were doped with Ag by implanting radioactive $^{111}\\!$Ag. Photoluminescence spectra of the crystals show a donor-acceptor pair (DAP) line at 1.491 eV. The decrease of the intensity of this line with a half life of T$_{1/2}$=(7.2$\\pm$0.4) d is in good agreement with the half life of the $\\beta\\!^{-}$-decay of $^{111}\\!$Ag to $^{111}\\!$Cd of 7.45 d. This decrease is not caused by the aging behavior of Ag which was reported in the literature. The data show that the involved acceptor defect contains exactly one Ag atom and confirm the earlier assignment of the acceptor to the AgCd defect. Based on the DAP line at 1.491 eV, the spectra did not reveal a contamination of the CdTe crystals by stable Ag.

  19. Ligand and counterion control of Ag(I) architectures: assembly of a {Ag8} ring cluster mediated by hydrophobic and Ag...Ag interactions.

    Science.gov (United States)

    Fielden, John; Long, De-liang; Slawin, Alexandra M Z; Kögerler, Paul; Cronin, Leroy

    2007-10-29

    A strategy combining ligand design and counterion variation has been used to investigate the assembly of silver(I) complexes. As a result, dinuclear, octanuclear, and polymeric silver(I) species have been synthesized by complexation of the rigid aliphatic amino ligands cis-3,5-diamino-trans-hydroxycyclohexane (DAHC), cis-3,5-diamino-trans-methoxycyclohexane (DAMC), and cis-3,5-diamino-trans-tert-butyldimethylsilylanyloxycyclohexane (DATC) with silver(I) triflate, nitrate, and perchlorate. The compositions of these aggregates, established by X-ray crystallography and elemental analysis, are [{Ag(DAHC)}2](CF3SO3)2 (1), [{Ag(DAMC)}2](CF3SO3)2 (2), [{Ag(DAMC)}2](NO3)2 (3), [{Ag(DATC)}6{Ag(DAHC)}2](NO3)8 (4), and [{Ag(DATC}n](NO3)n (5), where the DAHC present in 4 is formed by in situ hydrolysis of the acid labile silyl ether group. The type of aggregate formed depends both upon the noncoordinating O-substituent of the ligand and the (also noncoordinating) counterion, with the normal preference of the ligand topology for forming Ag2L2 structures being broken by introduction of the bulky, lipophilic O-tert-butyldimethylsilyl (TBDMS) group. Of particular note is the octanuclear silver ring structure 4, which is isolated only when both the O-TBDMS group and the nitrate counteranion are present and is formed from four Ag2L2 dimers connected by Ag...Ag and hydrogen-bonding interactions. Diffusion rate measurement of this {Ag8} complex by 1H NMR (DOSY) indicates dissociation in CD3OD and CD3CN, showing that this supramolecular ring structure is formed upon crystallization, and establishing a qualitative limit to the strength of Ag...Ag interactions in solution. When solutions of the {Ag8} cluster in methanol are kept for several days though, a new UV-vis absorption is observed at around 430 nm, consistent with the formation of silver nanoparticles.

  20. Solid phase metallurgy strategy to sub-5 nm Au-Pd and Ni-Pd bimetallic nanoparticles with controlled redox properties.

    Science.gov (United States)

    Tang, Yu; Xu, Shaodan; Dai, Yihu; Yan, Xiaoqing; Li, Renhong; Xiao, Liping; Fan, Jie

    2014-01-07

    A solid phase metallurgy strategy is applied to synthesize Au-Pd and Ni-Pd bimetallic nanoparticles (BMNPs) with a tight sub-5 nm particle size distribution. The near-surface elemental composition and redox properties of Au-Pd BMNPs can be well tailored, which leads to an optimized catalytic performance in n-hexane combustion.

  1. Improved sulfur-resistant ability on CO oxidation of Pd/Ce0.75Zr0.25O2 over Pd/CeO2-TiO2 and Pd/CeO2

    Institute of Scientific and Technical Information of China (English)

    沈美庆; 林放; 魏光曦; 王建强; 朱少春

    2015-01-01

    The influence of sulfation on Pd/Ce0.75Zr0.25O2, Pd/CeO2-TiO2 and Pd/CeO2 was investigated. Physical structure and chemical properties of different catalysts were characterized by N2 adsorption, X-ray diffraction (XRD), CO chemisorption, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and X-ray fluorescence (XRF). After 10 h SO2 sulfation, it was found that the decrement on CO oxidation catalytic activity was limited on Pd/Ce0.75Zr0.25O2 compared to Pd/CeO2-TiO2 and Pd/CeO2. It demonstrated that Pd/Ce0.75Zr0.25O2 was more sulfur resistant compared to the other two catalysts. Af-ter sulfur exposure, catalyst texture was not much influenced as shown by N2 adsorption and XRD, and surface Pd atoms were poi-soned indicated by CO chemisorption results. Pd/Ce0.75Zr0.25O2 and Pd/CeO2-TiO2 exhibited less sulfur accumulation compared to Pd/CeO2 in the sulfation process. Furthermore, XPS results clarified that surface sulfur amount, especially surface sulfates amount on the sulfated catalysts was more crucial for the deactivation in sulfur containing environment.

  2. Ab initio calculations on the structural, mechanical, electronic, dynamic, and optical properties of semiconductor half-Heusler compound ZrPdSn

    Energy Technology Data Exchange (ETDEWEB)

    Ciftci, Yasemin Oe. [Gazi Univ., Ankara (Turkey). Dept. of Physics; Coban, Cansu [Balikesir Univ. (Turkey). Dept. of Physics

    2016-05-01

    The structural, mechanical, electronic, dynamic, and optical properties of the ZrPdSn compound crystallising into the MgAgAs structure are investigated by the ab initio calculations based on the density functional theory. The lattice constant, bulk modulus, and first derivative of bulk modulus were obtained by fitting the calculated total energy-atomic volume results to the Murnaghan equation of state. These results were compared to the previous data. The band structure and corresponding density of states (DOS) were also calculated and discussed. The elastic properties were calculated by using the stress-strain method, which shows that the MgAgAs phase of this compound is mechanically stable. The presented phonon dispersion curves and one-phonon DOS confirms that this compound is dynamically stable. In addition, the heat capacity, entropy, and free energy of ZrPdSn were calculated by using the phonon frequencies. Finally, the optical properties, such as dielectric function, reflectivity function, extinction coefficient, refractive index, and energy loss spectrum, were obtained under different pressures.

  3. Potential of ZrO clusters as replacement Pd catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Behera, Swayamprabha; King, Nicholas; Jena, Puru, E-mail: pjena@vcu.edu [Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Samanta, Devleena [Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, USA and Department of Chemistry, Stanford University, Stanford, California 94305 (United States)

    2014-07-21

    Atomic clusters with specific size and composition and mimicking the chemistry of elements in the periodic table are commonly known as superatoms. It has been suggested that superatoms could be used to replace elements that are either scarce or expensive. Based on a photoelectron spectroscopy experiment of negatively charged ions, Castleman and co-workers [Proc. Natl. Acad. Sci. U.S.A. 107, 975 (2010)] have recently shown that atoms of Ni, Pd, and Pt which are well known for their catalytic properties, have the same electronic structure as their counterpart isovalent diatomic species, TiO, ZrO, and WC, respectively. Based on this similarity they have suggested that ZrO, for example, could be a replacement catalyst for Pd. Since catalysts are seldom single isolated atoms, one has to demonstrate that clusters of ZrO also have the same electronic structure as same sized Pd clusters. To examine if this is indeed the case, we have calculated the geometries, electronic structure, electron affinity, ionization potential, and hardness of Pd{sub n} and (ZrO){sub n} clusters (n = 1-5). We further studied the reaction of these clusters in neutral and charged forms with H{sub 2}, O{sub 2}, and CO and found it to be qualitatively different in most cases. These results obtained using density functional theory with hybrid B3LYP functional do not support the view that ZrO clusters can replace Pd as a catalyst.

  4. PERANCANGAN SISTEM INFORMASI PENJUALAN BUKU PADA PD. KENCANA

    Directory of Open Access Journals (Sweden)

    Maryani

    2014-12-01

    Full Text Available PD KENCANA is a company engaged in the sale of school administration equipment, office equipment and so forth. One of the processes that exist in PD KENCANA is the sales process. Based on book sales processes currently running on KENCANA PD, there are still some issues, namely duration of the process of making the sales memorandum book, because the manufacturing process is still done by hand writing. The purpose of this research is to design information systems in PD KENCANA book sales and provide reports on sales data of books with ease and on time. Methodology in the development of this system consists of activities which can be grouped into several stages, systems methodologies used in information system design uses the System Development Life Cycle (SDLC. Book Sales Information Systems In this KENCANA PD can assist the administration in managing the sale of books and making reports. In addition, this information system can also easily generate reports on book sales information per month or per year, accurate, precise and relevant, as expected.

  5. Hard Photodisintegration of 3He into pd pair

    CERN Document Server

    Maheswari, Dhiraj

    2016-01-01

    The recent measurements of high energy photodisintegration of the $^3He$ nucleus to the $pd$ pair at $90^0$ center of mass demonstrated an energy scaling consistent with the quark counting rule with unprecedentedly large exponent of $s^{-17}$. To understand the underlying mechanism of this process we extended the theoretical formalism of hard rescattering mechanism to calculate the $\\gamma ^3He\\rightarrow pd$ reaction. In HRM the incoming high energy photon strikes a quark from one of the nucleons in the target which subsequently undergoes hard rescattering with the quarks from the other nucleons generating hard two-body system in the final state of the reaction. Within the HRM we derived the parameter free expression for the differential cross section of the reaction, which is expressed through the $^3He\\rightarrow pd$ transition spectral function, cross section of hard $pd\\rightarrow pd$ scattering and the effective charge of the quarks being interchanged during the hard rescattering process. The numerical ...

  6. Preparation and Characterization of γ-AgI in Superionic Composite Glasses (AgIx(AgPO31-x

    Directory of Open Access Journals (Sweden)

    S. Suminta

    2007-07-01

    Full Text Available The γ-AgI phase was stabilized at room temperature in the composites glasses (AgIx(AgPO31-x with x = 0.6 and 0.7 via rapid quenching of their molten mixture. The measurement of the crystal structure has been carried out using an X-ray Difractometer at the Physics Departement of Ibaraki University, Japan. The micro strain and crystal size are derived from Hall’s equation. The X-ray diffraction pattern shows some Bragg peaks that correspond to the crystalline γ-AgI. By increasing the concentration of AgI, the peak width becomes more narrow and the position shifts to the higher angle. This indicates that the crystalline size and microstrain are increasing. The increase of micro strain (η, and particle size (D will increase the ionic mobility, thus increasing the ionic conductivity. It is concluded that solidification process on melt AgI into glass matrix AgPO3 not only decreases the micro strain and the particle size, but it also increases the ionic conductivity.

  7. The aerobic oxidation of a Pd(II) dimethyl complex leads to selective ethane elimination from a Pd(III) intermediate.

    Science.gov (United States)

    Khusnutdinova, Julia R; Rath, Nigam P; Mirica, Liviu M

    2012-02-01

    Oxidation of the Pd(II) complex (N4)Pd(II)Me(2) (N4 = N,N'-di-tert-butyl-2,11-diaza[3.3](2,6)pyridinophane) with O(2) or ROOH (R = H, tert-butyl, cumyl) produces the Pd(III) species [(N4)Pd(III)Me(2)](+), followed by selective formation of ethane and the monomethyl complex (N4)Pd(II)Me(OH). Cyclic voltammetry studies and use of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trap suggest an inner-sphere mechanism for (N4)Pd(II)Me(2) oxidation by O(2) to generate a Pd(III)-superoxide intermediate. In addition, reaction of (N4)Pd(II)Me(2) with cumene hydroperoxide involves a heterolytic O-O bond cleavage, implying a two-electron oxidation of the Pd(II) precursor and formation of a transient Pd(IV) intermediate. Mechanistic studies of the C-C bond formation steps and crossover experiments are consistent with a nonradical mechanism that involves methyl group transfer and transient formation of a Pd(IV) species. Moreover, the (N4)Pd(II)Me(OH) complex formed upon ethane elimination reacts with weakly acidic C-H bonds of acetone and terminal alkynes, leading to formation of a new Pd(II)-C bond. Overall, this study represents the first example of C-C bond formation upon aerobic oxidation of a Pd(II) dimethyl complex, with implications in the development of Pd catalysts for aerobic oxidative coupling of C-H bonds.

  8. High-pressure/high-temperature synthesis and characterization of the first palladium or platinum containing lithium transition-metal sulfides Li2M3S4 (M=Pd, Pt)

    Science.gov (United States)

    Heymann, Gunter; Niehaus, Oliver; Krüger, Hannes; Selter, Philipp; Brunklaus, Gunther; Pöttgen, Rainer

    2016-10-01

    The new lithium transition-metal sulfides Li2M3S4 (M=Pd, Pt) were obtained via multianvil high-pressure/high-temperature syntheses at 8 GPa and 1150 °C starting from a stoichiometric mixture of lithium nitride, sulfur, and palladium or platinum. Single crystal structure analyses indicated the space group P21/c (no. 14) with the following lattice parameters and refinement results: a=492.9(1), b=1005.9(2), c=614.9(2) pm, β=110.9 (1)°, R1=0.0165, wR2=0.0308 (all data) for Li2Pd3S4 and a=498.2(1), b=1005.5(2), c=613.0(2) pm, β=110.8(1)°, R1=0.0215, wR2=0.0450 (all data) for Li2Pt3S4. The crystal structures are built up from two distinct Pd/Pt sites, one of which is a special position (0,0,0), two sulfur sites, and one lithium site. The atoms Pd2/Pt2 form isolated square planar PdS4/PtS4 units, whereas the Pd1/Pt1 atoms form pairs of square planar PdS4/PtS4 units, which are connected via a common edge. These two structural motives built up a three-dimensional network structure by linking through common corners. The lithium atoms are positioned inside of the so formed channels. Li2M3S4 (M=Pd, Pt) are isostructural to the minerals jaguéite, Cu2Pd3Se4 and chrisstanleyite, Ag2Pd3Se4, which are up to now the only representatives of this structure type. Both compounds were studied with respect to their magnetic properties and can be classified as Pauli paramagnetic or diamagnetic. Regarding the possibility of lithium mobility inside the channels, of the structure, solid state 7Li NMR and high-temperature single crystal investigations revealed localization of the lithium atoms on their crystallographic sites.

  9. Preparation of Pd-Diimine@SBA-15 and Its Catalytic Performance for the Suzuki Coupling Reaction

    Directory of Open Access Journals (Sweden)

    Jiahuan Yu

    2016-11-01

    Full Text Available A highly efficient and stable Pd-diimine@SBA-15 catalyst was successfully prepared by immobilizing Pd onto diimine-functionalized mesoporous silica SBA-15. With the help of diimine functional groups grafted onto the SBA-15, Pd could be anchored on a support with high dispersion. Pd-diimine@SBA-15 catalyst exhibited excellent catalytic performance for the Suzuki coupling reaction of electronically diverse aryl halides and phenylboronic acid under mild conditions with an ultralow amount of Pd (0.05 mol % Pd. When the catalyst amount was increased, it could catalyze the coupling reaction of chlorinated aromatics with phenylboronic acid. Compared with the catalytic performances of Pd/SBA-15 and Pd-diimine@SiO2 catalysts, the Pd-diimine@SBA-15 catalyst exhibited higher hydrothermal stability and could be repeatedly used four times without a significant decrease of its catalytic activity.

  10. Spectroscopic Study on Eu3+ Doped Borate Glasses Containing Ag Nanoparticles and Ag Aggregates.

    Science.gov (United States)

    Fu, Shaobo; Zheng, Hui; Zhang, Jinsu; Li, Xiangping; Sun, Jiashi; Hua, Ruinian; Dong, Bin; Xia, Haiping; Chen, Baojiu

    2015-01-01

    Transparent Eu(3+)-doped borate glasses containing Ag nanoparticles and Ag aggregates with composition (40 - x) CaO-59.5B2O3-0.5Eu2O3-xAgNO3 were prepared by a simple one-step melt-quenching technique. The X-ray diffraction (XRD) patterns of the glasses reveal amorphous structural properties and no diffraction peaks belonging to metal Ag particles. Ag particles and Ag aggregates were observed from the absorption spectra. Effective energy transfers from the Ag aggregates to the Eu3+ ions were observed in the excitation spectra from monitoring the intrinsic emission of Eu3+x .5D0 --> 7F2. The glasses with higher Ag content can be effectively excited by light in a wide wavelength region, indicating that these glasses have potential application in the solid state lighting driven by semiconductor light emitting diodes (LEDs). The emission spectra of the samples with higher Ag contents exhibit plenteous spectral components covering the full visible region from violet to red, thus indicating that these glass materials possess an excellent and tunable color rendering index. The color coordinates for all the glass samples were calculated by using the intensity-corrected emission spectra and the standard data issued by the CIE (Commission International de l' Eclairage) in 1931. It was found that the color coordinates for most samples with higher Ag contents fall into the white region in the color space.

  11. Study of antibacterial activity of Ag and Ag2CO3 nanoparticles stabilized over montmorillonite.

    Science.gov (United States)

    Sohrabnezhad, Sh; Pourahmad, A; Mehdipour Moghaddam, M J; Sadeghi, A

    2015-02-05

    Silver carbonate and silver nanoparticles (NPs) over of stabilizer montmorillonite (MMT) have been synthesized in aqueous and polyol solvent, respectively. Dispersions of silver nanoparticles have been prepared by the reduction of silver nitrate over of MMT in presence and absence of Na2CO3 compound in ethylene glycol. It was observed that montmorillonite was capable of stabilizing formed Ag nanoparticles through the reduction of Ag(+) ions in ethylene glycol. Na2CO3 was used as carbonate source in synthesis of Ag2CO3 NPs in water solvent and also for controlling of Ag nanoparticles size in ethylene glycol medium. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and ultraviolet-visible diffuse reflectance spectroscopy (DRS). The TEM images showed that Ag NPs size in presence Na2CO3 salts was smaller than without that. The results indicated intercalation of Ag and Ag2CO3 nanoparticles into the montmorillonite clay layers. The diffuse reflectance spectra exhibited a strong surface plasmon resonance (SPR) adsorption peak in the visible region, resulting from Ag nanoparticles. The antibacterial testing results showed that the Ag2CO3-MMT nanocomposite exhibited an antibacterial activity higher than Ag-MMT sample against Escherichia coli.

  12. Diffusion behaviors of helium atoms at two Pd grain boundaries

    Institute of Scientific and Technical Information of China (English)

    XIA Ji-xing; HU Wang-yu; YANG Jian-yu; AO Bing-yun

    2006-01-01

    The diffusion behaviors of helium atoms at two symmetric grain boundaries (Σ5{210} and Σ3 {112}) of Pd were investigated using molecular dynamics simulations through an analytical embedded-atom method(MAEAM) model. The simulations demonstrate that the interstitial helium atoms are easily trapped at the grain boundaries and precipitated into clusters. Due to the closed-shell electronic configurations of both helium and palladium,Pd grain boundaries yield strong capability of retaining helium atoms. By calculating the mean square displacements(MSD) of an interstitial helium atom at the grain boundaries,the diffusion coefficients were determined,and the linear fits to Arrhenius relation. The diffusion activation energies of interstitial helium atom at these two Pd grain boundaries were also evaluated.

  13. Crystallization in Pd40Ni40P20 glass

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Saksl, K.; Nishiyama, N.;

    2002-01-01

    Phase segregation and the effect of pressure on crystallization of bulk and ribbon Pd40Ni40P20 glasses have been studied by means of differential scanning calorimetry (DSC) and x-ray diffraction. The DSC measurements show only one glass transition event in the samples annealed at different...... temperatures in the supercooled liquid region. Phase analyses reveal at least five crystalline phases crystallized from the glass: monoclinic; body-centered tetragonal; orthorhombic; Ni2Pd2P and fcc-(Ni,Pd) solid solution phases. In the pressure range from 0 to 4.2 GPa, the crystallization temperature...... increases with pressure having a slope of 11 K/GPa. The eutectic crystallization reaction mode and crystalline phases formed are unchanged in the pressure range used. The enhancement of the crystallization temperature with increasing pressure in the glass can be explained by the suppression of atomic...

  14. Synthesis and crystal structure of PdSnTe

    Energy Technology Data Exchange (ETDEWEB)

    Laufek, F. [Czech Geological Survey, Geologicka 6, 152 00 Praha 5 (Czech Republic)], E-mail: frantisek.laufek@geology.cz; Vymazalova, A. [Czech Geological Survey, Geologicka 6, 152 00 Praha 5 (Czech Republic); Navratil, J. [Joint Laboratory of Solid State Chemistry of IMC AS CR and University of Pardubice, Studentska 84, 532 10 Pardubice (Czech Republic); Drabek, M. [Czech Geological Survey, Geologicka 6, 152 00 Praha 5 (Czech Republic); Plasil, J. [Faculty of Science, Charles University, Albertov 6, 128 43 Praha 2 (Czech Republic); Plechacek, T. [Joint Laboratory of Solid State Chemistry of IMC AS CR and University of Pardubice, Studentska 84, 532 10 Pardubice (Czech Republic)

    2009-01-22

    The compound with composition PdSnTe was prepared by heating of stoichiometric amount of Pd, Sn and Te in silica glass tube at 400 deg. C. Its crystal structure was refined by Rietveld method using conventional X-ray powder diffraction data. PdSnTe shows orthorhombic symmetry, space group Pbca with unit cell parameters a = 6.5687(2), b = 6.6028(2), c = 12.8849(4) A, V = 558.8(1) A{sup 3} and Z = 8. The title compound can be viewed as a ternary-ordered variant of {alpha}-NiAs{sub 2}-type structure, it is isostructural with PtSiTe. Temperature dependence of electrical conductivity and Hall coefficient are presented, it suggests semimetallic or strongly degenerated semiconductor behaviour of the prepared compound.

  15. Performance of the PdNi and PdNiSe as cathodes in PEM fuel cells; Desempeno de PdNi y PdNiSe como catodos en celdas de combustible tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Santana, A.; Ramos-Sanchez, G.; Vazquez, G.; Solorza-Feria, O. [Centro de Investigaciones y de Estudios Avanzados del IPN, Mexico D.F. (Mexico)]. E-mail: gramos@cinvestav.mx

    2009-09-15

    The search for new materials capable of catalyzing oxygen reactions in low temperature fuel cells continues to be one of the key issues in the development of a hydrogen economy. Electrochemical and physical characterization studies have demonstrated that the PdNi and PdNiSe catalysts have adequate properties for use as cathodes in fuel cells. Nevertheless, the performance of the materials in proton exchange membrane (PEM) fuel cells depends not only on the catalytic properties but also on the adequate preparation of the electrocatalyst membrane interface (EMI). This work presents the results of the search for optimal conditions to prepare the EMIs with PdNi and PdNiSe cathodes. There are many variables for handling the preparation of the interfaces, nevertheless our search focuses on two: catalyst ratio/Vulcan Carbon® and the catalyst amount. Interfaces were prepared with an active area of 5 cm{sup 2} with PdNi and PdNiSe cathodes and carbon fabric anode with Pt E-tek®. These interfaces were tested with an ElectroChem model under different gas pressure and temperature conditions. The optimization method was carried out using a simplex method with the variables mentioned above and power density per unit mass and catalyst area as response variables. [Spanish] La busqueda de nuevos materiales capaces de catalizar la Reaccion de Oxigeno (RRO) en celdas de combustible de baja temperatura, sigue siendo uno de los temas clave para el desarrollo de una Economia del Hidrogeno. Estudios electroquimicos y de caracterizacion fisica han demostrado que los catalizadores PdNi y PdNiSe, tienen las propiedades adecuadas para poder ser utilizados como catodos en celdas de combustible; sin embargo el desempeno de los materiales en celdas de combustible de membrana de intercambio protonico (PEM), no solo depende de las propiedades del catalizador, sino tambien de la preparacion adecuada del Ensamble Membrana Electrocatalizador (EME). En este trabajo se presentan los resultados de la

  16. Development of Pd-based membranes as hydrogen diffusion anodes

    Energy Technology Data Exchange (ETDEWEB)

    Rego, Rosa; Oliveira, M. Cristina F. [Centro de Quimica de Vila Real, Departamento de Quimica, Universidade de Tras-os-Montes e Alto Douro, Apartado 1013, Vila Real (Portugal); Esparbe, Isaac; Cabot, Pere L. [Laboartori de Ciencia i Tecnologia Electroquimica de Materials, Department de Quimica-Fisica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain)

    2009-04-15

    Pd-based membranes have been prepared by Pd electroless deposition on porous stainless steel substrate and their structure, composition, morphology and thickness were analyzed by X-ray diffraction (XRD), EDS and scanning electronic microscopy (SEM). The performance of these membranes as hydrogen diffusion electrodes was evaluated in a three-electrode cell in alkaline medium. The activity towards hydrogen oxidation was high at the beginning of the experiment, but it significantly decreased with time. The major cause of this phenomenon has been attributed to the slow entry of hydrogen at the H{sub 2}/Pd interface. Even so, the technical feasibility of using these membranes as gas diffusion electrodes (GDE) has been proven. (author)

  17. DETECTION OF POINT MUTATIONS IN EXON 2 OF THE G6PD GENE IN CHINESE G6PD VARIANTS

    Institute of Scientific and Technical Information of China (English)

    许卫明; 王菁; 华小云; 杜传书

    1994-01-01

    In the past few years,a total of 6 different mutations of the G6PD gene have been reported in china.One of these,the C6 mutation(A95→G),accounted for about 15.4% of the Chinese G6PD variants.In ordet to develop a strategy for rapid detection of mutation-containing exons of the G6PD gene,we applied the single-strand confor-mation polymorphism(SSCP)technique to the detection of mutations in exon 2 of this gene.We observed four pa-tients with abnormal migration patterns of the exon 2 band among 20 cases of G6PD variants.Direct PCR se-quencing confirmed a Tto C substitution in exon 2 that has previously been reported.This procedure is therefore of particular importance for the rapid detection of mutation-containing exons in the G6PD gene.

  18. Ag nanoparticle/polymer composite barcode nanorods

    Institute of Scientific and Technical Information of China (English)

    Hongxu Chen[1; Tieqiang Wang[2; Huaizhong Shen[1; Wendong Liu[1; Shuli Wang[1; Kun Liu[1; Junhu Zhang[1; Bai Yang[1

    2015-01-01

    We demonstrate a facile method combining colloidal lithography, selective ion-exchange, and the in situ reduction of Ag ions (Ag+) for the fabrication of multi-segmented barcode nanorods. First, polymer multilayer films were prepared by spin-coating alternating thin films of polystyrene and polyacrylic acid (PAA), and then multi-segmented polymer nanorods were fabricated via reactive ion etching with colloidal masks. Second, Ag nanoparticles (Ag NPs) were incorporated into the PAA segments by an ion exchange and the in situ reduction of the Ag~. The selective incorporation of the Ag NPs permitted the modification of the specific bars of the nanorods. Lastly, the Ag NP/polymer composite nanorods were released from the substrate to form suspensions for further coding applications. By increasing the number of segments and changing the length of each segment in the nanorods, the coding capacity of nanorods was improved. More importantly, this method can easily realize the density tuning of Ag NPs in different segments of a single nanorod by varying the composition of the PAA segments. We believe that numerous other coded materials can also be obtained, which introduces new approaches for fabricating barcoded nanomaterials.

  19. Enhanced Fe2O3 Reducibility via Surface Modification with Pd: Characterizing the Synergy within Pd/Fe Catalysts for Hydrodeoxygenation Reactions

    Energy Technology Data Exchange (ETDEWEB)

    Hensley, Alyssa; Hong, Yongchun; Zhang, Renqin; Zhang, He; Sun, Junming; Wang, Yong; McEwen, Jean-Sabin

    2014-10-03

    The synergistic catalysis in the hydrodeoxygenation of phenolic compounds over a Pd/Fe bimetallic surface has been well established. However, the nature of this synergy is still in part a mystery. In this work, we used a combined experimental and theoretical approach to understand a potential function of the surface Pd in the reduction of Pd/Fe2O3. This function of Pd was investigated via the comparison of the reduction properties as well as other physicochemical properties of samples synthesized by the reduction of Fe2O3 nanoparticles with and without surface Pd. Temperature-programmed reduction studies demonstrated the remarkable facilitation of reduction by addition of Pd, evidenced by a 150 degrees C shift toward lower temperature of the reduction peak of Fe3+. From X-ray photoelectron spectroscopy and theoretical calculation results, the interaction between Pd and the Fe2O3 surface occurs through the exchange of electrons with both the surface Fe and O atoms. This bonding between the Pd and surface oxide elements causes the Pd to partially donate electrons to the oxide surface, making the surface electrons more delocalized. This electron delocalization stabilizes the reduced oxide surfaces, as suggested by the TPR results and theoretical prediction. Therefore, the stabilization of the reduced Fe surface as well as the facilitated water formation by introduction of Pd is expected to significantly contribute to the Pd-Fe synergy in hydrodeoxygenation catalysis.

  20. A first-principles study of Hg adsorption on Pd(1 1 1) and Pd/γ-Al2O3(1 1 0) surfaces

    Science.gov (United States)

    Geng, Lu; Han, Lina; Cen, Wanglai; Wang, Jiancheng; Chang, Liping; Kong, Dejin; Feng, Gang

    2014-12-01

    Spin-polarized density functional theory calculations were carried out to investigate the adsorption of Hgn (n = 1-3) on the perfect, step and vacancy-defective Pd(1 1 1) surfaces as well as the Pd/γ-Al2O3(1 1 0) surface. It is found that Hg atoms prefer to adsorb on the hollow sites on Pd(1 1 1) surfaces. The adsorption of Hg on the step and vacancy-defective Pd(1 1 1) surfaces is stronger than on the perfect Pd(1 1 1) surface, which indicates that the existence of vacancy and step defects can enhance the mercury adsorption activity of Pd adsorbents. As indicated by the calculated adsorption energies, the mercury adsorption on γ-Al2O3 is weak. The γ-Al2O3 supported single Pd atom shows as good Hg adsorption activity as the perfect Pd(1 1 1) surface at low Hg coverage, while more coordination unsaturated active Pd atoms is needed to achieve high Hg adsorption capacity. In addition, it was also found that the Hg adsorption on Pd/γ-Al2O3 weakens the binding of Pd to the γ-Al2O3 surface.

  1. Monitoring PD-L1 positive circulating tumor cells in non-small cell lung cancer patients treated with the PD-1 inhibitor Nivolumab.

    Science.gov (United States)

    Nicolazzo, Chiara; Raimondi, Cristina; Mancini, MariaLaura; Caponnetto, Salvatore; Gradilone, Angela; Gandini, Orietta; Mastromartino, Maria; Del Bene, Gabriella; Prete, Alessandra; Longo, Flavia; Cortesi, Enrico; Gazzaniga, Paola

    2016-08-24

    Controversial results on the predictive value of programmed death ligand 1 (PD-L1) status in lung tumor tissue for response to immune checkpoint inhibitors do not allow for any conclusive consideration. Liquid biopsy might allow real-time sampling of patients for PD-L1 through the course of the disease. Twenty-four stage IV NSCLC patients included in the Expanded Access Program with Nivolumab were enrolled. Circulating tumor cells (CTCs) were analyzed by CellSearch with anti-human B7-H1/PD-L1 PE-conjugated antibody. PD-L1 expressing CTCs were assessed at baseline, at 3 and 6 months after starting therapy, and correlated with outcome. At baseline and at 3 months of treatment, the presence of CTCs and the expression of PD-L1 on their surface were found associated to poor patients outcome. Nevertheless, the high frequency of PD-L1 expressing CTCs hampered to discriminate the role of PD-L1 in defining prognosis. Conversely although CTCs were found in all patients 6 months after treatment, at this time patients could be dichotomized into two groups based PD-L1 expression on CTCs. Patients with PD-L1 negative CTCs all obtained a clinical benefit, while patients with PD-L1 (+) CTCs all experienced progressive disease. This suggests that the persistence of PD-L1(+) CTCs might mirror a mechanism of therapy escape.

  2. Density functional theory study of the adsorption of formaldehyde on Pd4 and on Pd4/gamma-Al2O3 clusters.

    Science.gov (United States)

    Carneiro, José Walkimar de M; Cruz, Maurício T de M

    2008-09-25

    B3LYP/LANL2DZ and B3LYP/6-31G(d)-restricted and -unrestricted calculations are employed to calculate energies and adsorption forms of formaldehyde adsorbed on planar and on tetrahedral Pd4 clusters and on a Pd4 cluster supported on Al10O15. Formaldehyde adsorbs on planar Pd4 in the eta(2)(C,O)-di-sigma adsorption mode, while on tetrahedral Pd4, it adsorbs in the eta(2)(C,O)-pi adsorption mode. The adsorption energy on planar Pd4 is -21.4 kcal x mol(-1), whereas for the tetrahedral Pd4 cluster, the adsorption energy is -13.2 kcal x mol(-1). The latter value is close to experimental findings (-12 to -14 kcal x mol(-1)). Adsorption of formaldehyde on Pd4 supported on an Al10O15 cluster leads essentially to the same result as that found for adsorption on the tetrahedral Pd4 cluster. Charge density analysis for the interaction between formaldehyde and the Pd4 clusters indicates strong backdonation in the eta(2) adsorption mode, leading to positive charge on the Pd4 cluster. NBO analysis shows that the highly coordinated octahedral aluminum atoms of Al10O15 donate electron density to the supported Pd4 cluster, while tetrahedral aluminum atoms with lower coordination number have acidic nature and therefore act as electron acceptors.

  3. Computation and comparison of Pd-based membrane reactor performances for water gas shift reaction and isotope swamping in view of highly tritiated water decontamination

    Energy Technology Data Exchange (ETDEWEB)

    Santucci, Alessia, E-mail: alessia.santucci@enea.it [Associazione ENEA-Euratom sulla Fusione, C.R. ENEA Frascati, Via E. Fermi 45, 00044 Frascati, RM (Italy); Rizzello, Claudio [Tesi Sas, Via Bolzano 28, Roma (Italy); Tosti, Silvano [Associazione ENEA-Euratom sulla Fusione, C.R. ENEA Frascati, Via E. Fermi 45, 00044 Frascati, RM (Italy)

    2013-10-15

    Highlights: • A dedicated detritiation process for highly tritiated water (HTW) has to be identified. • Water gas shift and isotopic swamping via Pd–Ag membrane reactor are possible processes. • A parametric analysis through two simulation codes is performed. • A comparison in terms of the decontamination factor is provided. -- Abstract: In a D–T fusion machine, due to the possible reaction between tritium and oxygen, some potential sources of highly tritiated water (HTW) can be identified. Therefore, a dedicated detritiation process has to be assessed either for economic and safety reasons. In this view, the use of a Pd-based membrane reactor performing isotopic exchange reactions can be considered since hydrogen isotopes exclusively permeate the Pd–Ag membrane and their exchange over the catalyst realizes the water detritiation. In this activity, the treatment of highly tritiated water, generated by an ITER-like machine (i.e. 2 kg of stoichiometric HTO containing up to 300 g of tritium), via a Pd-membrane reactor is studied in terms of decontamination capability. Especially, a parametric analysis of two processes (water gas shift and isotopic swamping) performed in a Pd-based membrane reactor is carried out by using two mathematical models previously developed and experimentally verified. Particularly, the effect of the reactor temperature, the membrane thickness, the reaction pressure and the protium sweep flow-rate is investigated. Moreover, a comparison in terms of the decontamination factor and the number of reactors necessary to detritiate the HTW are provided. Generally, the results reveal a higher decontamination capability of the WGS reaction respect with the IS (maximum DF values of about 120 and 1.6 in the case of WGS and IS, respectively). However some drawbacks, mainly related with the formation of tritiated species, can occur by performing the WGS.

  4. Ore mineralogy of the Serra Pelada Au-Pd-Pt deposit, Carajás, Brazil and implications for ore-forming processes

    Science.gov (United States)

    Berni, Gabriel V.; Heinrich, Christoph A.; Lobato, Lydia M.; Wall, Vic

    2016-08-01

    Serra Pelada is a world-class hydrothermal Au-Pd-Pt deposit located at the eastern border of the Amazon craton, northern Brazil. The rocks at Serra Pelada have experienced intense tropical weathering for about 70 Ma, but drill core samples preserve the primary mineralogy and hydrothermal alteration features, with extreme grades of Au, Pd and Pt individually reaching hundreds of parts per million (ppm) by weight. Mineralization at Serra Pelada occurs in hydrothermally altered metasiltstones and dolomitic metasandstones at the hinge zone of a recumbent syncline, comprising zones of hematite, chlorite-carbon, argillic, and siliceous alteration. The main hydrothermal gangue minerals are quartz, kaolinite, sericite, amesite, hematite, monazite, florencite and variable amounts of highly reflective carbonaceous matter. Hydrothermal carbon input is evident from precipitated carbon occurring along crenulation planes and veinlets associated with the precious metals. Ore and accessory minerals include a variety of sulphide, selenide, arsenide, sulphate and oxide minerals, including gold with variable metal contents, palladian gold, fischesserite, sudovikovite, sperrylite, selenian braggite, isomertieite, mertieite-II and secondary Au-Pt-Pd alloys. The composition of fischesserite varies from the ideal formula (Ag3AuSe2) towards a more Ag-rich composition, indicating a disordered solid solution form that is stable only above 260 °C, consistent with the high thermal maturity of associated carbonaceous matter approaching graphite. Primary ore and gangue minerals at Serra Pelada comprise a suite of elements that are best transported in oxidising conditions and precipitated upon reduction. This suggests that fluid mixing between a highly oxidised (metal carrier) and a reduced fluid was a key process for high-grade noble metal precipitation at Serra Pelada.

  5. Study of The Pd-B/γ-Al2O3 Amorphous Alloy Catalyst

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The Pd-B/γ-Al2O3 amorphous alloy catalyst and Pd/γ-Al2O3 crystalline metal catalyst were prepared by KBH4 reduction and routine impregnation, respectively. Pd-B/γ-A12O3 and Pd/γ-A12O3 catalysts were characterized by XRD and SEM. It was found that the catalytic activity of the Pd-B/γ-A12O3 amorphous alloy catalyst was higher than that of the Pd/γ-A12O3crystalline metal catalyst in the anthraquinone hydrogenation.

  6. A dimeric structure of PD-L1: functional units or evolutionary relics?

    OpenAIRE

    Chen, Yong; Liu, Peipei; Gao, Feng; Cheng, Hao; Qi, Jianxun; Gao, George F

    2010-01-01

    PD-L1 is a member of the B7 protein family, most of whose members so far were identified as dimers in a solution and crystalline state, either complexed or uncomplexed with their ligand(s). The binding of PD-L1 with its receptor PD-1 (CD279) delivers an inhibitory signal regulating the T cell function. Simultaneously with the Garboczi group, we successfully solved another structure of human PD-L1 (hPD-L1). Our protein crystallized in the space group of C2221 with two hPD-L1 molecules per asym...

  7. Predictive Maintenance (PdM) Centralization for Significant Energy Savings

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Dale

    2010-09-15

    Cost effective predictive maintenance (PdM) technologies and basic energy calculations can mine energy savings form processes or maintenance activities. Centralizing and packaging this information correctly empowers facility maintenance and reliability professionals to build financial justification and support for strategies and personnel to weather global economic downturns and competition. Attendees will learn how to: Systematically build a 'pilot project' for applying PdM and tracking systems; Break down a typical electrical bill to calculate energy savings; Use return on investment (ROI) calculations to identify the best and highest value options, strategies and tips for substantiating your energy reduction maintenance strategies.

  8. Enhanced quantum coherence in graphene caused by Pd cluster deposition

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Yuyuan; Han, Junhao; Du, Yongping; Li, Zhaoguo; Wan, Xiangang; Han, Min; Song, Fengqi, E-mail: songfengqi@nju.edu.cn [National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and Department of Physics, Nanjing University, Nanjing 210093 (China); Guo, Guoping [Key Lab of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026 (China); Song, You [Collaborative Innovation Center of Advanced Microstructures, State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Pi, Li [High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230027 (China); Wang, Xuefeng [School of Electronic Science and Engineering and National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China)

    2015-01-12

    We report on the unexpected increase in the dephasing lengths of a graphene sheet caused by the deposition of Pd nanoclusters, as demonstrated by weak localization measurements. The dephasing lengths reached saturated values at low temperatures. Theoretical calculations indicate the p-type charge transfer from the Pd clusters, which contributes more carriers. The saturated values of dephasing lengths often depend on both the carrier concentration and mean free path. Although some impurities are increased as revealed by decreased mobilities, the intense charge transfer leads to the improved saturated values and subsequent improved dephasing lengths.

  9. A non-linear UAV altitude PSO-PD control

    Science.gov (United States)

    Orlando, Calogero

    2015-12-01

    In this work, a nonlinear model based approach is presented for the altitude stabilization of a hexarotor unmanned aerial vehicle (UAV). The mathematical model and control of the hexacopter airframe is presented. To stabilize the system along the vertical direction, a Proportional Derivative (PD) control is taken into account. A particle swarm optimization (PSO) approach is used in this paper to select the optimal parameters of the control algorithm taking into account different objective functions. Simulation sets are performed to carry out the results for the non-linear system to show how the PSO tuned PD controller leads to zero the error of the position along Z earth direction.

  10. PD-pulse characteristics in rotating machine insulation

    DEFF Research Database (Denmark)

    Holbøll, Joachim; Henriksen, Mogens; Jensen, A;

    1994-01-01

    In this paper results are presented from investigations on partial discharges (PD) in insulation systems, resembling the stator insulation in high voltage rotating machines. A model, simulating a stator winding in a slot, has been developed, consisting of simple rotating machine insulation test...... bars with epoxy/mica insulation, mounted between steel sheets forming a dot, in order to investigate the fundamental behaviour of PD in insulation defects in epoxy/mica insulation and the characteristics of the resulting electrical pulses. Stator slot couplers (SSC) were used to detect pulses coming...

  11. A FLYING WIRE SYSTEM IN THE AGS.

    Energy Technology Data Exchange (ETDEWEB)

    HUANG,H.; BUXTON,W.; MAHLER,G.; MARUSIC,A.; ROSER,T.; SMITH,G.; SYPHERS,M.; WILLIAMS,N.; WITKOVER,R.

    1999-03-29

    As the AGS prepares to serve as the injector for RHIC, monitoring and control of the beam transverse emittance become a major and important topic. Before the installation of the flying wire system, the emittance was measured with ionization profile monitors in the AGS, which require correction for space charge effects. It is desirable to have a second means of measuring profile that is less depend on intensity. A flying wire system has been installed in the AGS recently to perform this task. This paper discusses the hardware and software setup and the capabilities of the system.

  12. GLUT1 as a Prognostic Factor for Classical Hodgkin’s Lymphoma: Correlation with PD-L1 and PD-L2 Expression

    Science.gov (United States)

    Koh, Young Wha; Han, Jae-Ho; Park, Seong Yong; Yoon, Dok Hyun; Suh, Cheolwon; Huh, Jooryung

    2017-01-01

    Background Glucose transporter type 1 (GLUT1) expression is linked to glucose metabolism and tissue hypoxia. A recent study reported that GLUT1 was significantly associated with programmed death ligand 1 (PD-L1) as a therapeutic target in relapsed or refractory classical Hodgkin’s lymphoma (cHL). The purpose of this study was to measure the expression of GLUT1 and assess its prognostic significance and potential relationships with PD-L1, programmed death ligand 2 (PD-L2), and programmed death-1 (PD-1) expressions in cHL. Methods Diagnostic tissues from 125 patients with cHL treated with doxorubicin, bleomycin, vinblastine, and dacarbazine were evaluated retrospectively via immunohistochemical analysis of GLUT1, PD-L1, PD-L2, and PD-1 expression. Results The median follow-up time was 4.83 years (range, 0.08 to 17.33 years). GLUT1, PD-L1, PD-L2, and PD-1 were expressed in 44.8%, 63.2%, 9.6%, and 13.6% of the specimens, respectively. Positive correlations were found between GLUT1 and PD-L1 expression (p = .004) and between GLUT1 and PD-L2 expression (p = .031). GLUT1 expression in Hodgkin/Reed-Sternberg (HRS) cells was not associated with overall survival or event-free survival (EFS) in the entire cohort (p = .299 and p = .143, respectively). A subgroup analysis according to the Ann Arbor stage illustrated that GLUT1 expression in HRS cells was associated with better EFS in advanced-stage disease (p = .029). A multivariate analysis identified GLUT1 as a marginally significant prognostic factor for EFS (p = .068). Conclusions This study suggests that GLUT1 expression is associated with better clinical outcomes in advanced-stage cHL and is significantly associated with PD-L1 and PD-L2 expressions. PMID:28219001

  13. Optical properties of AgI/Ag infrared hollow fiber in the visible wavelength region.

    Science.gov (United States)

    Sui, Ke-Rong; Shi, Yi-Wei; Tang, Xiao-Li; Zhu, Xiao-Song; Iwai, Katsumasa; Miyagi, Mitsunobu

    2008-02-15

    We report on AgI/Ag infrared hollow fiber with low-loss in visible region. Improved methods of silver plating and iodination were proposed to fabricate the hollow fiber. The surface roughness of the silver layer and the silver iodide layer was reduced by the pretreatment with an SnCl2 solution and low iodination temperature. Losses for the Er:YAG and green laser light were 0.4 and 7dB/m. The loss property of green laser beam was low to deliver a pilot beam for the invisible infrared laser light. Owing to the smooth and uniform AgI film, the loss spectrum of the hollow fiber showed clear interference peaks in the visible region. An empirical formula for AgI material dispersion was derived, which is of special importance for the design of high-performance AgI/Ag hollow fiber.

  14. Theoretical Investigation on the Adsorption of Ag+ and Hydrated Ag+ Cations on Clean Si(111)Surface

    Institute of Scientific and Technical Information of China (English)

    SHENG Yong-Li; LI Meng-Hua; WANG Zhi-Guo; LIU Yong-Jun

    2008-01-01

    In this paper,the adsorption of Ag+ and hydrated Ag+ cations on clean Si(111)surface were investigated by using cluster(Gaussian 03)and periodic(DMol3)ab initio calculations.Si(111)surface was described with cluster models(Si14H17 and Si22H21)and a four-silicon layer slab with periodic boundary conditions.The effect of basis set superposition error(BSSE)was taken into account by applying the counterpoise correction.The calculated results indicated that the binding energies between hydrated Ag+ cations and clean Si(111)surface are large,suggesting a strong interaction between hydrated Ag+ cations and the semiconductor surface.With the increase of number,water molecules form hydrogen bond network with one another and only one water molecule binds directly to the Ag+ cation.The Ag+ cation in aqueous solution will safely attach to the clean Si(111)surface.

  15. Ag-rich precipitates formation in the Cu–11%Al–10%Mn–3%Ag alloy

    Energy Technology Data Exchange (ETDEWEB)

    Silva, R.A.G., E-mail: galdino.ricardo@gmail.com [Departamento de Ciências Exatas e da Terra, UNIFESP, 09972-270 Diadema, SP (Brazil); Paganotti, A.; Jabase, L. [Departamento de Ciências Exatas e da Terra, UNIFESP, 09972-270 Diadema, SP (Brazil); Adorno, A.T.; Carvalho, T.M.; Santos, C.M.A. [Departamento de Físico-Química, Instituto de Química, UNESP, 14801-970 Araraquara, SP (Brazil)

    2014-12-05

    Highlights: • Cu-rich nanoprecipitates are formed in the presence of Ag. • Bainite precipitation is shifted to higher temperatures in the Cu–11%Al–10%Mn–3%Ag alloy. • The eutectoid α phase and bainite α{sub 1} phase compete by the Cu atoms during precipitation process. - Abstract: The formation of Ag-rich precipitates in the Cu–11%Al–10%Mn–3%Ag alloy initially quenched from 1123 K was analyzed. The results showed that nanoprecipitates of a Cu-rich phase are produced at about 523 K. In higher temperatures these nanoparticles grow and the relative fraction of Ag dissolved in it is increased, thus forming the Ag-rich phase.

  16. Study of coordination environments around Pd and Pt in a Pd-core Pt-shell nanoparticle during heating

    Science.gov (United States)

    Nishimura, Y. F.; Hamaguchi, T.; Yamaguchi, S.; Takagi, H.; Dohmae, K.; Nonaka, T.; Nagai, Y.

    2016-05-01

    Local coordination environments around Pd and Pt in a Pd-core Pt-shell nanoparticle (NP) at temperatures ranging from 473 to 873 K was evaluated by utilizing in situ XAFS measurement technique to investigate the temperature range in which a core-shell structure is preserved. The core-shell structure was considered to be kept up to 673 K and start to change at about 773 K. Heating to 873 K accelerated atomic mixing in the core-shell NPs. Catalytic properties of the present Pd-core Pt-shell NP are available in the stoichiometric C3H6-O2 atmosphere at temperatures less than 773 K at most.

  17. Transition metal oxides - CrO, MoO, NiO, PdO, AgO

    Science.gov (United States)

    Bauschlicher, C. W., Jr.; Nelin, C. J.; Bagus, P. S.

    1985-01-01

    The transition-metal oxides are quite ionic; Mulliken population analyses for several oxides give a negative charge of about 0.7 electrons for oxygen. When the transition-metal d shell is only partially filled, the orbitals are involved in covalent bonds with O; both two-electron bonding (2)-antibonding (0) and one-electron bonding (2)-antibonding (1) bonds are formed. These covalent bonds occur in addition to the ionic bonding. There is d-sigma-O2 p sigma repulsion, and this repulsion is reduced when the d-sigma electron is promoted into an orbital which has dominantly 4sp-sigma character and is polarized away from O.

  18. Novel Galvanic Nanostructures of Ag and Pd for Efficient Laser Desorption/Ionization of Low Molecular Weight Compounds

    Science.gov (United States)

    Silina, Yuliya E.; Meier, Florian; Nebolsin, Valeriy A.; Koch, Marcus; Volmer, Dietrich A.

    2014-05-01

    A simple approach for synthesis of palladium and silver nanostructures with readily adjustable morphologies was developed using galvanic electrochemical deposition, for application to surface-assisted laser desorption/ionization (SALDI) of small biological molecules. A range of fatty acids, triglycerides, carbohydrates, and antibiotics were investigated to assess the performance of the new materials. Intense analyte cations were generated from the galvanic surfaces upon UV laser irradiation such as potassium adducts for a film thickness 120 nm. Possible laser desorption/ionization mechanisms of these galvanic structures are discussed. The films exhibited self-organizing abilities and adjustable morphologies by changing electrochemical parameters. They did not require any stabilizing agents and were inexpensive and very easy to produce. SALDI analysis showed that the materials were stable under ambient conditions and analytical results with excellent measurement reproducibility and detection sensitivity similar to MALDI were obtained. Finally, we applied the galvanic surfaces to fast screening of natural oils with minimum sample preparation.

  19. A GREENER SYNTHESIS OF CORE (FE, CU)-SHELL (AU, PT, PD AND AG) NANOCRYSTALS USING AQUEOUS VITAMIN C

    Science.gov (United States)

    A greener method to fabricate the novel core (Fe and Cu)-shell (noble metals) metal nanocrystals using aqueous ascorbic acid (vitamin C) is described. Transition metal salts such as Cu and Fe were reduced using ascorbic acid, a benign naturally available antioxidant, and then add...

  20. Comparative toxicity study of Ag, Au, and Ag-Au bimetallic nanoparticles on Daphnia magna.

    Science.gov (United States)

    Li, Ting; Albee, Brian; Alemayehu, Matti; Diaz, Rocio; Ingham, Leigha; Kamal, Shawn; Rodriguez, Maritza; Bishnoi, Sandra Whaley

    2010-09-01

    A comparative assessment of the 48-h acute toxicity of aqueous nanoparticles synthesized using the same methodology, including Au, Ag, and Ag-Au bimetallic nanoparticles, was conducted to determine their ecological effect in freshwater environments through the use of Daphnia magna, using their mortality as a toxicological endpoint. D. magna are one of the standard organisms used for ecotoxicity studies due to their sensitivity to chemical toxicants. Particle suspensions used in toxicity testing were well-characterized through a combination of absorbance measurements, atomic force or electron microscopy, flame atomic absorption spectrometry, and dynamic light scattering to determine composition, aggregation state, and particle size. The toxicity of all nanoparticles tested was found to be dose and composition dependent. The concentration of Au nanoparticles that killed 50% of the test organisms (LC(50)) ranged from 65-75 mg/L. In addition, three different sized Ag nanoparticles (diameters = 36, 52, and 66 nm) were studied to analyze the toxicological effects of particle size on D. magna; however, it was found that toxicity was not a function of size and ranged from 3-4 μg/L for all three sets of Ag nanoparticles tested. This was possibly due to the large degree of aggregation when these nanoparticles were suspended in standard synthetic freshwater. Moreover, the LC(50) values for Ag-Au bimetallic nanoparticles were found to be between that of Ag and Au but much closer to that of Ag. The bimetallic particles containing 80% Ag and 20% Au were found to have a significantly lower toxicity to Daphnia (LC(50) of 15 μg/L) compared to Ag nanoparticles, while the toxicity of the nanoparticles containing 20% Ag and 80% Au was greater than expected at 12 μg/L. The comparison results confirm that Ag nanoparticles were much more toxic than Au nanoparticles, and that the introduction of gold into silver nanoparticles may lower their environmental impact by lowering the amount

  1. Cross-coupling of C(sp)-H Bonds with Organometallic Reagents via Pd(II)/Pd(0) Catalysis**

    Science.gov (United States)

    Wasa, Masayuki; Engle, Keary M; Yu, Jin-Quan

    2010-12-01

    Palladium-catalyzed C-H activation/C-C bond-forming reactions have emerged as a promising class of synthetic tools in organic chemistry. Among the many different means of forging C-C bonds using Pd-mediated C-H activation, a new horizon in this field is Pd(II)-catalyzed cross-coupling of C-H bonds with organometallic reagents via a Pd(II)/Pd(0) catalytic cycle. While this type of reaction has proven to be effective for the selective functionalization of aryl C(sp(2))-H bonds, the focus of this review is on Pd(II)-catalyzed C(sp(3))-H activation/C-C cross-coupling, a topic of particular importance because reactions of this type enable fundamentally new methods for bond construction. Since our laboratory's initial report on cross-coupling of C-H bonds in 2006, this area has expanded rapidly, and the unique ability of Pd(II) catalysts to cleave and functionalize alkyl C(sp(3))-H bonds has been exploited to develop protocols for forming an array of C(sp(3))-C(sp(2)) and C(sp(3))-C(sp(3)) bonds. Furthermore, enantioselective C(sp(3))-H activation/C-C cross-coupling has been achieved through the use of chiral amino acid-derived ligands, offering a novel technique for producing enantioenriched molecules. Although this nascent field remains at an early stage of development, further investigations hold the potential to revolutionalize the way in which chiral molecules are synthesized in industrial and academic laboratories.

  2. PD-L2: A prognostic marker in chromophobe renal cell carcinoma?

    Science.gov (United States)

    Erlmeier, Franziska; Weichert, Wilko; Autenrieth, Michael; Wiedemann, Max; Schrader, Andres Jan; Hartmann, Arndt; Ivanyi, Philipp; Steffens, Sandra

    2017-05-01

    In the context of cancer immunotherapy, PD-1 as well as PD-L1 has been widely studied in renal cell carcinoma (RCC). PD-1 and PD-L1 play a significant role as prognostic markers in clear cell renal cell carcinoma. In contrast, little is known about PD-L2 expression patterns in RCC, especially in rarer subtypes. The aim of this study was to evaluate the prevalence, distribution and prognostic impact of PD-L2 expression in chromophobe (ch)RCC. Eighty-one patients who underwent renal surgery due to chRCC were retrospectively evaluated. Tumor specimens were analyzed for PD-L2 expression by immunohistochemistry. Expression data were associated with clinicopathological parameters and overall survival (OS). Twenty-three (28.4%) patients showed a PD-L2 > median (PD-L2 high) staining intensity. No significant association between clinicopathological parameters and PD-L2 expression was identified. A significant difference between 5- and 10-year OS in dependence of PD-L2 expression was found (PD-L2 low 96.4 and 87.7% vs. PD-L2 high 87.1 and 56%; log rank, p = 0.029). However, in multivariate analysis PD-L2 expression failed to be proofed as an independent prognostic factor. In conclusion, to our knowledge this is the first study evaluating the prognostic impact of PD-L2 in a considerably large cohort of chRCC. Our results showed a significant diminished OS in dependence of PD-L2 expression. This implicates that PD-L2 might play a role as prognostic marker in chRCC demanding further evaluation.

  3. Epigallocatechin-3-gallate-capped Ag nanoparticles: preparation and characterization.

    Science.gov (United States)

    Hussain, Shokit; Khan, Zaheer

    2014-07-01

    We used an aqueous leaf extract of Camellia sinensis to synthesize Ag nanoparticles (AgNPs). A layer of ca. 6 nm around a group of the AgNPs in which the inner layer is bound to the AgNPs surface via the hydroxyl groups of catechin has been observed. TEM analysis of AgNPs showed the formation of truncated triangular nanoplates and/or nanodisks and spherical with some irregular-shaped polydispersed nanoparticles in absence and presence of shape-directing cetyltrimethylammonium bromide. The polyphenolic groups of epigallocatechin-3-gallate (EGCG) are responsible for the rapid reduction of Ag(+) ions into metallic Ag(0). The free -OH groups are able to stabilize AgNPs by the interaction between the surface Ag atoms of AgNPs and oxygen atoms of EGCG molecules.

  4. Structure and Hydrogen Adsorption Properties of SBA-15 Doped with Pd Nanoparticles.

    Science.gov (United States)

    Lee, Sang-Hwa; Park, Taehee; Yi, Whikun; Kim, Jaeyong

    2015-11-01

    Hydrogen adsorption properties of Pd-doped Santa Barbara amorphous No. 15 (Pd-SBA-15) were investigated and the results were compared with pure SBA-15 ones in terms of change of its structure and Pd concentration. Pd-SBA-15 samples were prepared by a hydrothermal reaction, using mixture of PEO20PPO70PEO20 (P123) and tetraethyl orthosilicate (TEOS). For the doping of Pd on SBA-15, PdC2 solution was added into the mixture of P123 and TEOS, and the solution was annealed at 80 degrees C for 2 hours under 800 Torr of hydrogen atmosphere. According to the X-ray diffraction and transmission electron microscope data, Pd-doped SBA-15 samples form a hexagonal array of mesoporous structure with 20-30 nm size of Pd particles. Values of specific surface area decreased from 630 to 414 m2/g as increasing the Pd doping level due to the increasing of the volume density. In fact, the volume density increased from 0.103 to 0.276 g/cc as increasing the mass ratio of PdCl2 to TEOS from 0 to 0.5. For the Pd-doped SBA-15, the amount of adsorbed hydrogen significantly increased from 0.49 to 0.99 wt% as increasing the Pd doping level from 0 to 0.5 demonstrating that Pd doping is an effect method for SBA-1 5 as a potential use of hydrogen storage application.

  5. Refoiding and Characterization of Recombinant Human GST-PD-1 Fusion Protein Expressed in Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    Da-WeiLI; Jian-FengYU; Yong-JingCHEN; Hong-BingMA; Zheng-FeiWANG; Yi-BeiZHU; Xue-GuangZHANG

    2004-01-01

    Programmed death-1 (PD-1) is a costimulatory molecule of CD28 family expressed onactivated T, B and myeloid cells. The engagement of PD-1 with its two ligands, PD-L1 and PD-L2, inhibitsproliferation of T cell and production of a series of its cytokines. The blockade of PD-1 pathway is involvedin antiviral and antitumoral immunity. In this study, human PD-1 cDNA encoding extracellular domain wasamplified and cloned into expression plasmid pGEX-Sx-3. The fusion protein GST-PD-1 was effectivelyexpressed in E. coli BL21 (DE3) as inclusion bodies and a denaturation and refolding procedure was per-formed to obtain bioactive soluble GST-PD-I. Fusion protein of above 95% purity was acquired by a conve-nient two-step purification using GST affinity and size exclusion columns. Furthermore, a PD-L1-dependentin vitro bioassay method was set up to characterize GST-PD-1 bioactivity. The results suggested that GST-PD-1 could competently block the interaction between PD-Ll and PD-l and increase the production of IL-2 and IFN-γ of phytohemagglutinin-activated T cells.

  6. Pd/C催化剂中钯的回收%Recovery of Palladium from Spent Pd/C Catalyst

    Institute of Scientific and Technical Information of China (English)

    贺红军; 周雪莹; 邹旭华; 安立敦

    2003-01-01

    研究了从废Pd/C催化剂中得到高回收率粗钯的方法,研究了从粗钯回收高纯度钯的3种方法,提出了1种工艺简单、效果好、成本低、易操作的从废Pd/C催化剂中回收钯的方法.试验表明,本方法适用于实际生产应用.

  7. AgSat Imagery Collection Footprints

    Data.gov (United States)

    Farm Service Agency, Department of Agriculture — The AgSat Imagery Collection Footprints map shows the imagery footprints which have been collected under the USDA satellite blanket purchase agreement. Click on a...

  8. AgSat Areas of Interest

    Data.gov (United States)

    Farm Service Agency, Department of Agriculture — The AgSat Areas of Interest map contains area polygons where satellite imagery will be collected for the Farm Service Agency (FSA) to provide imagery coverage for...

  9. Redetermination of AgPO(3).

    Science.gov (United States)

    Terebilenko, Katherina V; Zatovsky, Igor V; Ogorodnyk, Ivan V; Baumer, Vyacheslav N; Slobodyanik, Nikolay S

    2011-02-09

    Single crystals of silver(I) polyphosphate(V), AgPO(3), were prepared via a phospho-ric acid melt method using a solution of Ag(3)PO(4) in H(3)PO(4). In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779-784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO(5)] polyhedra, giving rise to multidirectional ribbons, and from two types of PO(4) tetra-hedra linked into meandering chains (PO(3))(n) spreading parallel to the b axis with a repeat unit of four tetra-hedra. The calculated bond-valence sum value of one of the two Ag(I) ions indicates a significant strain of the structure.

  10. Redetermination of AgPO3

    Science.gov (United States)

    Terebilenko, Katherina V.; Zatovsky, Igor V.; Ogorodnyk, Ivan V.; Baumer, Vyacheslav N.; Slobodyanik, Nikolay S.

    2011-01-01

    Single crystals of silver(I) polyphosphate(V), AgPO3, were prepared via a phospho­ric acid melt method using a solution of Ag3PO4 in H3PO4. In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779–784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO5] polyhedra, giving rise to multidirectional ribbons, and from two types of PO4 tetra­hedra linked into meandering chains (PO3)n spreading parallel to the b axis with a repeat unit of four tetra­hedra. The calculated bond-valence sum value of one of the two AgI ions indicates a significant strain of the structure. PMID:21522230

  11. Temperature stability of AgCu nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Sopoušek, Jiří, E-mail: sopousek@mail.muni.cz; Zobač, Ondřej; Vykoukal, Vít [Masaryk University, Department of Chemistry, Faculty of Science (Czech Republic); Buršík, Jiří; Roupcová, Pavla [Institute of Physics of Materials ASCR (Czech Republic); Brož, Pavel; Pinkas, Jiří [Masaryk University, Department of Chemistry, Faculty of Science (Czech Republic); Vřešťál, Jan [Masaryk University, Central European Institute of Technology, CEITEC (Czech Republic)

    2015-12-15

    The colloidal solutions of the Ag–Cu nanoparticles (NPs, 10–32 nm) were prepared by solvothermal reactions. The samples of dried AgCu NPs and the resulting microstructures after heat treatment in air were investigated by various methods including electron microscopy (TEM, SEM) and high-temperature X-ray powder diffraction (HTXRD). The AgCu randomly mixed, Cu-rich, and Ag-rich face centred cubic crystal lattices were detected during the experiments. The temperature induced sintering was observed experimentally by HTXRD at 250 °C. The phase transformations at high temperatures were monitored by differential scanning calorimetry. The formation of the Ag-rich grains during heating in air and evolution of copper oxide microstructure were detected.Graphical abstract.

  12. PdMn and PdFe: New Materials for Temperature Measurement Near 2K

    Energy Technology Data Exchange (ETDEWEB)

    Aselage, T.L.; Duncan, R.V.; Klemme, B.J.; Sergatskov, D.A.; Adriaans, M.J.; Day, P.K.

    1999-02-01

    Interest in the critical dynamics of superfluid He in microgravity conditions has motivated the development of new high resolution thermometry technology for use in space experiments near 2K. The current material commonly used as the temperature sensing element for high resolution thermometers (HRTs) is copper ammonium bromide (Cu(NH{sub 4}){sub 2}Br{sub 4}2H{sub 2}O) or CAB, which undergoes a ferromagnetic phase transition at 1.8K. HRTs made from CAB have demonstrated low drift (<10fK/s) and a temperature resolution of 0.1nK. Unfortunately, paramagnetic salts such as CAB are difficult to prepare and handle, corrosive to most metals, and become dehydrated if kept under vacuum conditions at room temperature. We have developed a magnetic thermometer using dilute magnetic alloys of Mn or Fe dissolved in a pure Pd matrix. These metallic thermometers are easy to fabricate, chemically inert, and mechanically robust. Unlike salts, they may be directly soldered to the stage to be measured. Also, the Curie temperature can be varied by changing the concentration of Fe or Mn, making them available for use in a wide temperature range. Susceptibility measurements, as well as preliminary noise and drift measurements, show them to have sub-nK resolution with a drift of less than 10{sup {minus}13} K/s.

  13. HBsAg, HBcAg, and combined HBsAg/HBcAg-based therapeutic vaccines in treating chronic hepatitis B virus infection

    Institute of Scientific and Technical Information of China (English)

    Sheikh Mohammad Fazle Akbar; Mamun Al-Mahtab

    2013-01-01

    BACKGROUND: As  the  host  immunity  is  diminished  in patients with chronic hepatitis B (CHB), different approaches have  been  used  to  up-regulate  their  immune  responses  to produce therapeutic effects. But, cytokines, growth factors and polyclonal  immune  modulators  could  not  exhibit  sufficient therapeutic  effects  in  these  patients.  Immune  therapy  with HBV-related antigens (vaccine therapy) has been used in CHB patients. But there is a paucity of information about the design of HBV antigen-based immune therapy in these patients. DATA  SOURCE: Preclinical  and  clinical  studies  on  immune therapy with HBsAg-based vaccine, HBcAg and combination of HBsAg/HBcAg-based vaccines have been discussed. RESULTS: HBsAg-based  prophylactic  vaccine  was  used  as an  immune  therapeutic  agent  in  CHB  patients;  however, monotherapy  with  HBsAg-based  immune  therapy  could not  lead  to  sustained  control  of  HBV  replication  and/or  liver damages.  HBsAg-based  vaccine  was  used  as  a  combination therapy  with  cytokines,  growth  factors,  and  antiviral  drugs. HBsAg-based  vaccine  was  also  used  for  cell-based  therapy. However,  satisfactory  therapeutic  effects  of  HBsAg-based vaccine could not be documented in CHB patients. In the mean time, evidences have supported that HBcAg-specific immunity is  endowed  with  antiviral  and  liver  protecting  capacities  in CHB  patients.  Recent  data  concentrate  on  the  clinical  use  of combined HBsAg- and HBcAg-based vaccines in CHB patients. CONCLUSION: Antigen-based  immune  therapy

  14. Hydrodeoxygenation of phenol over Pd catalysts by in-situ generated hydrogen from aqueous reforming of formic acid

    DEFF Research Database (Denmark)

    Zeng, Ying; Wang, Ze; Lin, Weigang

    2016-01-01

    Hydrodeoxygenation of phenol, as model compound of bio-oil, was investigated over Pd catalysts, using formic acid as a hydrogen donor. The order of activity for deoxygenation of phenol with Pd catalysts was found to be: Pd/SiO2 > Pd/MCM-41 > Pd/CA > Pd/Al2O3 > Pd/HY approximate to Pd/ZrO2 ≈ Pd....../CW > Pd/HSAPO-34 > Pd/HZSM-5. The good performance of Pd/SiO2 is owing to its proper pore structure and large specific surface area. The high level of Bronsted acid sites in SiO2 also favors the deoxygenation of phenol. (C) 2016 Elsevier B.V. All rights reserved....

  15. Monolayer solid of N-2/Ag(111)

    DEFF Research Database (Denmark)

    Bruch, L.W.; Hansen, Flemming Yssing

    1998-01-01

    An incommensurate monolayer solid of N-2/Ag(111) is modeled using extensive molecular-dynamics simulations. The conditions treated range from the low-temperature orientationally ordered solid to the melting of the solid. The properties are evaluated as a function of spreading pressure. Comparison...... is made to recent experimental data for N-2/Ag(111) and to results for N-2 adsorbed on graphite. Cu(110), and MgO(001). [S0163-1829(98)02715-5]....

  16. 48 CFR 726.7102 - PD 20 provision.

    Science.gov (United States)

    2010-10-01

    ... Section 726.7102 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT SOCIOECONOMIC PROGRAMS OTHER SOCIOECONOMIC PROGRAMS Relocation of U.S. Businesses, Assistance to Export Processing Zones, Internationally Recognized Workers' Rights 726.7102 PD 20 provision. Relocation of U.S. Businesses, Assistance...

  17. Laser stimulated extraction of Pd from solution with uranyl

    Energy Technology Data Exchange (ETDEWEB)

    Vlasov, M.; Mironov, S. [Gosudarstvennyj Komitet po Ispol`zovaniyu Atomnoj Ehnergii SSSR, Moscow (Russian Federation). Inst. Atomnoj Ehnergii; Krynetsky, B.; Kukhtenko, A.; Prokhorov, A.; Zhidkov, A.

    1995-03-01

    Have been investigated process of the extraction of metal palladium from solution Pd{sup 2}+HClO{sub 4}+(UO{sub 2}{sup 2+}) by radiation excimer XeCl-laser ({lambda}=308 nm). By optimal parameters of solution efficiency of extraction was about 100%. Have been discussed processes reduction of palladium by resonance laser action. (author).

  18. Estimation of Medium Voltage Cable Parameters for PD Detection

    DEFF Research Database (Denmark)

    Villefrance, Rasmus; Holbøll, Joachim T.; Henriksen, Mogens

    1998-01-01

    Medium voltage cable characteristics have been determined with respect to the parameters having influence on the evaluation of results from PD-measurements on paper/oil and XLPE-cables. In particular, parameters essential for discharge quantification and location were measured. In order to relate...

  19. A Patient with G6PD Deficiency and Falciparum Malaria

    Directory of Open Access Journals (Sweden)

    Y Fagani

    2007-04-01

    Full Text Available A 20 year old male patient from Afghanistan with a history of G6PD deficiency and clinical manifestations of malaria referred to Bou-Ali Hospital in Tehran, capital of Iran. Giemsa stained thick blood films revealed an infection of Plasmodium falciparum with 33700 parasite/μL of blood. The patient was successfully treated according to malaria treatment guideline.

  20. Salmonella induces PD-L1 expression in B cells.

    Science.gov (United States)

    Lopez-Medina, Marcela; Perez-Lopez, Araceli; Alpuche-Aranda, Celia; Ortiz-Navarrete, Vianney

    2015-10-01

    Salmonella persists for a long time in B cells; however, the mechanism(s) through which infected B cells avoid effector CD8 T cell responses has not been characterized. In this study, we show that Salmonella infects and survives within all B1 and B2 cell subpopulations. B cells are infected with a Salmonella typhimurium strain expressing an ovalbumin (OVA) peptide (SIINFEKL) to evaluate whether B cells process and present Salmonella antigens in the context of MHC-I molecules. Our data showed that OVA peptides are presented by MHC class I K(b)-restricted molecules and the presented antigen is generated through proteasomal degradation and vacuolar processing. In addition, Salmonella-infected B cells express co-stimulatory molecules such as CD40, CD80, and CD86 as well as inhibitory molecules such as PD-L1. Thus, the cross-presentation of Salmonella antigens and the expression of activation molecules suggest that infected B cells are able to prime and activate specific CD8(+) T cells. However, the Salmonella infection-stimulated expression of PD-L1 suggests that the PD-1/PD-L1 pathway may be involved in turning off the cytotoxic effector response during Salmonella persistent infection, thereby allowing B cells to become a reservoir for the bacteria.

  1. PD-1 blockade expands intratumoral T memory cells

    Science.gov (United States)

    Ribas, Antoni; Shin, Daniel Sanghoon; Zaretsky, Jesse; Frederiksen, Juliet; Cornish, Andrew; Avramis, Earl; Seja, Elizabeth; Kivork, Christine; Siebert, Janet; Kaplan-Lefko, Paula; Wang, Xiaoyan; Chmielowski, Bartosz; Glaspy, John A.; Tumeh, Paul C.; Chodon, Thinle; Pe’er, Dana; Comin-Anduix, Begoña

    2016-01-01

    Tumor responses to PD-1 blockade therapy are mediated by T cells, which we characterized in 102 tumor biopsies obtained from 53 patients treated with pembrolizumab, an antibody to PD-1. Biopsies were dissociated and single cell infiltrates were analyzed by multicolor flow cytometry using two computational approaches to resolve the leukocyte phenotypes at the single cell level. There was a statistically significant increase in the frequency of T cells in patients who responded to therapy. The frequency of intratumoral B cells and monocytic myeloid-derived suppressor cells (moMDSCs) significantly increased in patients’ biopsies taken on treatment. The percentage of cells with a T regulatory phenotype, monocytes, and NK cells did not change while on PD-1 blockade therapy. CD8+ T memory cells were the most prominent phenotype that expanded intratumorally on therapy. However, the frequency of CD4+ T effector memory cells significantly decreased on treatment, whereas CD4+ T effector cells significantly increased in nonresponding tumors on therapy. In peripheral blood, an unusual population of blood cells expressing CD56 were detected in two patients with regressing melanoma. In conclusion, PD-1 blockade increases the frequency of T cells, B cells, and MDSCs in tumors, with the CD8+ T effector memory subset being the major T-cell phenotype expanded in patients with a response to therapy. PMID:26787823

  2. Postural inflexibility in PD: does it affect compensatory stepping?

    NARCIS (Netherlands)

    Smulders, K.; Esselink, R.A.J.; Swart, B.J.M. de; Geurts, A.C.H.; Bloem, B.R.; Weerdesteyn, V.G.M.

    2014-01-01

    Parkinson's disease (PD) impairs the ability to shape postural responses to contextual factors. It is unknown whether such inflexibility pertains to compensatory steps to overcome balance perturbations. Participants were instructed to recover balance in response to a platform translation. A step was

  3. Phosphorimager and PD densitometer imaging system network. Technical report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-05-01

    This document discusses the research projects undertaken as a result of the availability of the PhosphorImager and PD Densitometer Imaging System Network, at the University of Georgia`s Complex Carbohydrate Research Center. The benefit gained from the equipment is described for each project.

  4. Parkinson's disease (PD is the most common neurodegenerative disease

    Directory of Open Access Journals (Sweden)

    P. A. Andoskin

    2015-01-01

    Full Text Available Metabolic impairment of alpha-synuclein protein is considered to be the central event in PDpathogenesis. Recent studies explored usage of alpha-synuclein in peripheral fluids as a biomarker of PD, however alpha-synuclein level in the CSF and plasma is considered to be affected by hemolysis. In order to avoid contamination of a lymphocyte fraction by erythrocytes, we have proposed an algorithm based on measurements of alpha-synuclein levels in the homogeneous CD45+ cell blood fraction. For this study we formed a group of PD patients (N=14 and a control group without the neurological disorders (N=17. We found an increase in the level of the total alpha-synuclein in CD45+ cells of PD patients compared to controls (p = 0,04, and revealed a direct correlation between the level of dopamine in plasma and level of total alpha-synuclein in CD45+ cells in the control group (r=0,71, p = 0,007.The level of alpha-synuclein in CD45+ cells could be suggested as possible PD biomarker.

  5. Precipitation hardening of biodegradable Fe-Mn-Pd alloys

    Energy Technology Data Exchange (ETDEWEB)

    Moszner, F. [Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich (Switzerland); Sologubenko, A.S. [Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich (Switzerland); Laboratory for Nanometallurgy, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich (Switzerland); Schinhammer, M. [Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich (Switzerland); Lerchbacher, C. [Christian Doppler Laboratory for Early Stages of Precipitation, University of Leoben, Franz-Josef-Strasse 18, 8700 Leoben (Austria); Haenzi, A.C. [Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich (Switzerland); Leitner, H. [Christian Doppler Laboratory for Early Stages of Precipitation, University of Leoben, Franz-Josef-Strasse 18, 8700 Leoben (Austria); Uggowitzer, P.J. [Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich (Switzerland); Loeffler, J.F., E-mail: joerg.loeffler@mat.ethz.ch [Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich (Switzerland)

    2011-02-15

    This work presents a phenomenological description of the precipitation controlled hardening of a new biodegradable Fe-based alloy developed to fulfill the requirements of temporary implant applications. Pronounced strengthening of the solution-treated martensitic Fe-10Mn-1Pd (in wt.%) alloy upon isothermal aging at temperatures within the ferrite-austenite phase field is observed and attributed to the thermally activated formation of coherent plate-like Pd-rich precipitates on {l_brace}1 0 0{r_brace} planes of the matrix. The onset and the early stages of alloy decomposition were studied using two complementary techniques: transmission electron microscopy and three-dimensional atom probe analysis. Three distinct regions of the hardening kinetics are recognized and closely correlated to the evolution of the alloy microstructure. Upon aging, clustering of Pd atoms within the Fe-Mn solid solution occurs. The very small clusters grow, coarsen and adopt a plate-like shape, rearranging mutually to reduce the overall elastic strain energy. The elastic interaction of the dislocation substructure with Pd-rich precipitates of evolving morphology affects the dislocation mobility and is responsible for the hardness evolution of the alloy. A study of the hardening kinetics shows that the process exhibits all the features characteristic of maraging steels.

  6. Solving and analyzing PD0L inverse process

    Institute of Scientific and Technical Information of China (English)

    樊勇兵; 陈刚; 董光昌

    2001-01-01

    The importance of L inverse process is emphasized and an algorithm is given to realize PD0L inverse process. On the basis of algorithm analysis, this note discusses the possibility of applying L inverse process to data compression and the difficulties in doing that.

  7. CO2 hydrogenation over Pd-modified methanol synthesis catalysts

    NARCIS (Netherlands)

    Melián-Cabrera, I.; López Granados, M.; Terreros, P.; Fierro, J.L.G.

    1998-01-01

    The effect of palladium incorporation on the performance of Cu-ZnO(Al2O3) during the hydrogenation of carbon dioxide has been assessed. Temperature-programmed reduction profiles and X-ray photoelectron spectra of copper revealed that Pd enhances copper oxide reduction. Carbon dioxide conversion and

  8. Negotiation of values as driver in community-based PD

    DEFF Research Database (Denmark)

    Gronvall, Erik; Malmborg, Lone; Messeter, Jörn

    2016-01-01

    and design things; and different accounts of values in design. Inspired by the concept of design things, and as a consequence of the need for continuous negotiation of values observed in all three cases, we suggest the concept of thinging as fruitful for creating productive agonistic spaces with a stronger...... attention towards the process of negotiating values in community-based PD....

  9. Antibacterial Ag/a-C nanocomposite coatings: The influence of nano-galvanic a-C and Ag couples on Ag ionization rates

    Energy Technology Data Exchange (ETDEWEB)

    Manninen, N.K., E-mail: nora.sousa@dem.uc.pt [SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); GRF-CFUM, Physics Department, University of Minho, Campus of Azurém, 4800-058 Guimarães (Portugal); Calderon, S. [SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); GRF-CFUM, Physics Department, University of Minho, Campus of Azurém, 4800-058 Guimarães (Portugal); Carvalho, I. [GRF-CFUM, Physics Department, University of Minho, Campus of Azurém, 4800-058 Guimarães (Portugal); CEB—Centre of Biological Engineering, LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, 4710-057 Braga (Portugal); Henriques, M. [CEB—Centre of Biological Engineering, LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, 4710-057 Braga (Portugal); Cavaleiro, A. [SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); Carvalho, S. [SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); GRF-CFUM, Physics Department, University of Minho, Campus of Azurém, 4800-058 Guimarães (Portugal)

    2016-07-30

    Highlights: • Amorphous carbon (a-C), Ag/a-C and Ag coatings were deposited by magnetron sputtering. • a-C/Ag coating shows antibacterial activity against S. epidermidis. • The formation of nano-galvanic couples in a-C/Ag enhances the Ag{sup +} ionization rate. • The Ag{sup +} ionization occurs along with Ag nanoparticles agglomeration in 0.9% NaCl. - Abstract: Biofilm formation has been pointed as a major concern in different industrial applications, namely on biomedical implants and surgical instruments, which has prompted the development of new strategies for production of efficient antimicrobial surfaces. In this work, nano-galvanic couples were created to enhance the antibacterial properties of silver, by embedding it into amorphous carbon (a-C) matrix. The developed Ag/a-C nanocomposite coatings, deposited by magnetron sputtering, revealed an outstanding antibacterial activity against Staphylococcus epidermidis, promoting a total reduction in biofilm formation with no bacteria counts in all dilution. The open circuit potential (OCP) tests in 0.9% NaCl confirmed that a-C shows a positive OCP value, in contrast to Ag coating, thus enhancing the ionization of biocidal Ag{sup +} due to the nano-galvanic couple activation. This result was confirmed by the inductively coupled plasma-optical emission spectroscopy (ICP-OES), which revealed a higher Ag ionization rate in the nanocomposite coating in comparison with the Ag coating. The surface of Ag/a-C and Ag coatings immersed in 0.9% NaCl were monitored by scanning electron microscopy (SEM) over a period of 24 h, being found that the Ag ionization determined by ICP-OES was accompanied by an Ag nanoparticles coalescence and agglomeration in Ag/a-C coating.

  10. Replication of association between ELAVL4 and Parkinson disease: the GenePD study

    Science.gov (United States)

    DeStefano, Anita L.; Latourelle, Jeanne; Lew, Mark F.; Suchowersky, Oksana; Klein, Christine; Golbe, Lawrence I.; Mark, Margery H.; Growdon, John H.; Wooten, G. Fredrick; Watts, Ray; Guttman, Mark; Racette, Brad A.; Perlmutter, Joel S.; Marlor, Lynn; Shill, Holly A.; Singer, Carlos; Goldwurm, Stefano; Pezzoli, Gianni; Saint-Hilaire, Marie H.; Hendricks, Audrey E.; Gower, Adam; Williamson, Sally; Nagle, Michael W.; Wilk, Jemma B.; Massood, Tiffany; Huskey, Karen W.; Baker, Kenneth B.; Itin, Ilia; Litvan, Irene; Nicholson, Garth; Corbett, Alastair; Nance, Martha; Drasby, Edward; Isaacson, Stuart; Burn, David J.; Chinnery, Patrick F.; Pramstaller, Peter P.; Al-hinti, Jomana; Moller, Anette T.; Ostergaard, Karen; Sherman, Scott J.; Roxburgh, Richard; Snow, Barry; Slevin, John T.; Cambi, Franca; Gusella, James F.; Myers, Richard H.

    2009-01-01

    Genetic variants in embryonic lethal, abnormal vision, Drosophila-like 4 (ELAVL4) have been reported to be associated with onset age of Parkinson disease (PD) or risk for PD affection in Caucasian populations. In the current study we genotyped three single nucleotide polymorphisms in ELAVL4 in a Caucasian study sample consisting of 712 PD patients and 312 unrelated controls from the GenePD study. The minor allele of rs967582 was associated with increased risk of PD (odds ratio = 1.46, nominal P value = 0.011) in the GenePD population. The minor allele of rs967582 was also the risk allele for PD affection or earlier onset age in the previously studied populations. This replication of association with rs967582 in a third cohort further implicates ELAVL4 as a PD susceptibility gene. PMID:18587682

  11. Comparison of bacterial cells and amine-functionalized abiotic surfaces as support for Pd nanoparticle synthesis

    DEFF Research Database (Denmark)

    De Corte, Simon; Bechstein, Stefanie; Lokanathan, Arcot R.

    2013-01-01

    An increasing demand for catalytic Pd nanoparticles has motivated the search for sustainable production methods. An innovative approach uses bacterial cells as support material for synthesizing Pd nanoparticles by reduction of Pd(II) with e.g. hydrogen or formate. Nevertheless, drawbacks...... nanoparticles, and that abiotic surfaces could support the Pd particle synthesis as efficiently as bacteria. In this study, we explore the possibility of replacing bacteria with amine-functionalized materials, and we compare different functionalization strategies. Pd nanoparticles formed on the support...... of microbially supported Pd catalysts are the low catalytic activity compared to conventional Pd nanocatalysts and the possible poisoning of the catalyst surface by sulfur originating from bacterial proteins. A recent study showed that amine groups were a key component in surface-supported synthesis of Pd...

  12. Intermetallic compounds, copper and palladium alloys in Au-Pd ore of the Skaergaard pluton, Greenland

    Science.gov (United States)

    Rudashevsky, N. S.; Rudashevsky, V. N.; Nielsen, T. F. D.

    2015-12-01

    Copper-palladium intermetallic compounds and alloys (2314 grains) from the Au-Pd ore of the Skaergaard layered gabbroic pluton have been studied. Skaergaardite PdCu, nielsenite PdCu3, (Cu,Pd)β, (Cu,Pd)α, (Pd,Cu,Au,Pt) alloys, and native palladium have been identified as a result of 1680 microprobe analyses. The average compositions and various chemical varieties of these minerals are characterized, as well as vertical and lateral zoning in distribution of noble metals. The primary Pd-Cu alloys were formed within a wide temperature interval broadly synchronously with cooling and crystallization of host gabbro and in close association with separation of Fe-Cu sulfide liquid. In the course of crystallization of residual gabbroic melt enriched in iron, noble and heavy metals and saturated with the supercritical aqueous fluid, PGE and Au are selectively concentrated in the Fe-Cu sulfide phase as Pd-Cu and Cu-Au alloys.

  13. Preparation and Electrochemical Properties of the Pd-modified Cu Electrode for Nitrate Reduction in Water

    Institute of Scientific and Technical Information of China (English)

    Ying WANG; Jiu Hui QU; Hui Juan LIU

    2006-01-01

    The Pd-modified Cu (Pd/Cu) electrodes for nitrate reduction were prepared using electro-deposition method at different potentials. Compared with other different electrodes so far studied in our work (Cu, Sn/Cu and Pd/Ti electrode) using cyclic voltammetry method, Pd/Cu electrode showed the highest electrocatalytic capacity of nitrate reduction. It was found that at more negative electrode potential the smaller Pd particles formed on the Cu electrode, which was beneficial to the nitrate reduction. With increasing deposition amount of Pd, the capacity of nitrate reduction increased. Too rich Pd, however, has a negative influence on the capacity of nitrate reduction. In our study, the maximum nitrate reduction current was 2.07 mA/cm2, when electrodeposition potential of Pd was -0.3 V and deposition amount was 0.9 C.

  14. Biodiversity and evolutionary history: useful extensions of the PD phylogenetic diversity assessment framework.

    Science.gov (United States)

    Faith, Daniel P

    2013-06-01

    Evolutionary biology is a core discipline in biodiversity science. Evolutionary history or phylogeny provides one natural measure of biodiversity through the popular phylogenetic diversity (PD) measure. The evolutionary model underlying PD means that it can be interpreted as quantifying the relative feature diversity of sets of species. Quantifying feature diversity measures possible future uses and benefits or option values. Interpretation of PD as counting-up features is the basis for an emerging broad family of PD calculations, of use to both biodiversity researchers and decision makers. Many of these calculations extend conventional species-level indices to the features level. Useful PD calculations include PD complementarity and endemism, Hill and Valley numbers incorporating abundance, and PD dissimilarities. A flexible analysis framework is provided by expected PD calculations, applied to either probabilities of extinction or presence-absence. Practical extensions include phylogenetic risk analysis and measures of distinctiveness and endemism. These support the integration of phylogenetic diversity into biodiversity conservation and monitoring programs.

  15. TPO characterization of ethanol reduced Pd nanoparticles supported on SiO$_{2}$

    CERN Document Server

    Horváth, A; Sarkany, A; Guczi, L

    2002-01-01

    Silica-supported Pd catalysts were prepared at 298-353 K from Pd(II) chloride or Pd(II) acetate in suspension of SiO/sub 2/ and ethanol- water or ethanol-toluene mixtures, respectively. Reduction of Pd ions diffusing from liquid phase was ensured in an ethanol-rich adsorption layer covering the SiO/sub 2/ particles. Temperature-programmed oxidation (TPO) measurements were performed to characterize the organic impurities retained by solid phase. Vapour phase reduction /adsorption experiments with ethanol confirmed that under the reported reduction conditions, the Pd nanoparticles decompose ethanol and the CO formed remains chemisorbed on the Pd sites. Upon contacting the samples with air during the drying process to eliminate the solvent, the CO molecules are immediately removed from Pd sites by O/sub 2/, and thereby, a significant fraction (22-34%) of Pd sites becomes accessible for catalytic reactions. (33 refs).

  16. The phase system Cu-Pd-S at 900, 725, 550 and 400 degree C

    DEFF Research Database (Denmark)

    Karup-Møller, Sven; Makovicky, Emil

    1999-01-01

    The condensed Cu-Pd-S system was studied by means of dry syntheses from elements in evacuated silica glass tubes at 900 degrees, 725 degrees, 550 degrees and 400 degrees C. At 900 degrees C the system contains Cu2-xS (with up to 0.7 at.% Pd), PdS, a broad sulfide melt field and continuous Cu......-Pd alloy. At 725 degrees the melt field breaks up into 2 melts and Pd4S appears. No melt was found at 550 degrees C. At 550 degrees and 400 degrees C the alloy field is split, containing beta CuPd which dissolves up to 2.6 at.% S. At these temperatures, the system is dominated by Cu2-xS (traces of Pd), Pd4...

  17. Performance increase of microfluidic formic acid fuel cell using Pd/MWCNTs as catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Acosta, D.; Rodriguez G., H.; Godinez, Luis A.; Arriaga, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, S.C. Parque Tecnologico Queretaro Sanfandila, P.O. Box 064, Pedro Escobedo, 76703 Queretaro (Mexico)

    2010-04-02

    This paper shows that the combination of an O{sub 2} saturated acidic fluid setup (O{sub 2}-setup) and a composite of Pd nanoparticles supported on multiwalled-carbon nanotubes (Pd/MWCNTs) as anode catalyst material, results in the improvement of microfluidic fuel cell performance. Microfluidic fuel cells were constructed and evaluated at low HCOOH concentrations (0.1 and 0.5 M) using Pd/V XC-72 and Pd/MWCNTs as anode and Pt/V XC-72 as cathode electrode materials, respectively. The results show a higher power density (2.9 mW cm{sup -2}) for this cell when compared to the value reported in the literature that considers a commercial Pd/V XC-72 and 3.3 mW cm{sup -2} using a Pd/MWCNTs with a 50% less Pd loading than that commercial Pd/V XC-72. (author)

  18. Influence of microstructure and mechanical stress on behavior of hydrogen in 500 nm Pd films

    Energy Technology Data Exchange (ETDEWEB)

    Vlček, Marián, E-mail: Marian.Vlcek@gmail.com [Faculty of Mathematics and Physics, Charles University in Prague, V Holešovičkách 2, CZ-18000 Praha 8 (Czech Republic); Lukáč, František; Vlach, Martin [Faculty of Mathematics and Physics, Charles University in Prague, V Holešovičkách 2, CZ-18000 Praha 8 (Czech Republic); Wagner, Stefan; Uchida, Helmut [Institute of Materials Physics, University of Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen (Germany); Baehtz, Carsten; Shalimov, Artem [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, D-01314 Dresden (Germany); Pundt, Astrid [Institute of Materials Physics, University of Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen (Germany); Čížek, Jakub [Faculty of Mathematics and Physics, Charles University in Prague, V Holešovičkách 2, CZ-18000 Praha 8 (Czech Republic)

    2015-10-05

    Highlights: • Influence of nano-structure and stresses on hydrogenation of Pd films was studied. • Nanocrystalline Pd films deposited on hard and soft substrates were compared. • It was found that nanocrystalline structure leads to narrowing of the miscibility gap. • Compressive in-plane stress suppresses the hydride formation. • The lattice constants for α-phase and the hydride phase are closer than in bulk Pd. - Abstract: Pd films can be used as a model system to examine the influence of microstructure and stress on the hydrogen absorption. In this work we study 500 nm Pd films deposited on different substrates with different binding strengths. The films were electrochemically loaded with hydrogen up to hydride concentration. Development of lattice constant during hydrogen loading of Pd films was investigated by in situ X-ray diffraction using synchrotron radiation. The influence of microstructure and mechanical stress in the films on the phase transition from Pd to Pd hydride was examined.

  19. Acceleration of polarized protons in the AGS

    Energy Technology Data Exchange (ETDEWEB)

    Tsoupas, N.; Ahrens, L.; Bai, M.; Brown, K.; Courant, E.; Glenn, J.W.; Huang, H.; Luccio, A.; MacKay, W.W.; Roser, T.; Schoefer, V.; Zeno, K.

    2010-02-25

    The high energy (s{sup 1/2} = 500 GeV) polarized proton beam experiments performed in RHIC, require high polarization of the proton beam. With the AGS used as the pre-injector to RHIC, one of the main tasks is to preserve the polarization of the proton beam, during the beam acceleration in the AGS. The polarization preservation is accomplished by the two partial helical magnets [1,2,3,4,5,6,7] which have been installed in AGS, and help overcome the imperfection and the intrinsic spin resonances which occur during the acceleration of protons. This elimination of the intrinsic resonances is accomplished by placing the vertical tune Q{sub y} at a value close to 8.98, within the spin-tune stop-band created by the snake. At this near integer tune the perturbations caused by the partial helical magnets is large resulting in large beta and dispersion waves. To mitigate the adverse effect of the partial helices on the optics of the AGS, we have introduced compensation quads[2] in the AGS. In this paper we present the beam optics of the AGS which ameliorates this effect of the partial helices.

  20. Growth kinetics and mechanism of Pd{sub 2}Zn{sub 9} at the interface of Pd substrate with molten Sn–9wt.%Zn solder

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chao-Hong, E-mail: chmchw@ccu.edu.tw; Li, Kuan-Ting

    2015-08-15

    A uniform Pd{sub 2}Zn{sub 9} layer was formed at the interface between liquid-state Sn–9wt.%Zn and Pd substrate. Detailed observation revealed a unique cruciform pattern formation of the Pd{sub 2}Zn{sub 9} phase. The Pd{sub 2}Zn{sub 9} layer ruptured at the edges, where no reaction phase was formed. The growth kinetics of Pd{sub 2}Zn{sub 9} was systematically investigated at temperatures of 220–260 °C. In particular, a linear reaction-limited growth was found in the initial reaction stage. While growing to approximately 5 μm thick, the growth rate gradually decreased over the subsequent reaction and obeyed a parabolic relationship. The growth kinetics parameters and the corresponding activation energies were determined. Additionally, the microstructure in the Pd{sub 2}Zn{sub 9} layer was characterized using focused ion beam microscopy. The Pd{sub 2}Zn{sub 9} layer consisted of four distinct sublayers with different grain structures. The growth behavior of Pd{sub 2}Zn{sub 9} was further discussed through a series of observations on microstructural evolutions at different reaction durations. - Highlights: • Linear growth of Pd{sub 2}Zn{sub 9} was found in the liquid-state Sn–9wt.%Zn/Pd reaction. • After growing to ~5 μm thick, the parabolic growth became dominant. • Unique cruciform pattern formation was observed in the Pd{sub 2}Zn{sub 9} phase. • FIB characterization revealed that the Pd{sub 2}Zn{sub 9} consisted of four sublayers. • The growth kinetics and mechanism of Pd{sub 2}Zn{sub 9} were discussed.