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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. Alumina supported model Pd Ag catalysts: A combined STM, XPS, TPD and IRAS study

    Science.gov (United States)

    Khan, N. A.; Uhl, A.; Shaikhutdinov, S.; Freund, H.-J.

    2006-05-01

    The bimetallic Pd-Ag model catalysts were prepared by physical vapor deposition on thin alumina films. The morphology and structure of the Pd-Ag particles were studied by STM, XPS, and by TPD and IRAS of CO. The results showed the formation of true alloy particles with Ag segregated at the surface. The addition of Ag first suppresses the most strongly bonded CO on threefold hollow sites of Pd. With further increasing Ag coverage, only isolated Pd atoms surrounded by Ag atoms are likely present on the surface. The results on CO adsorption suggest that the model Pd-Ag system mimics the structure of the real Pd-Ag catalysts.

  5. An optical fiber hydrogen sensor with Pd/Ag film

    Institute of Scientific and Technical Information of China (English)

    CUI Lu-jun; CHEN You-ping; ZHANG Gang

    2009-01-01

    A 20 nanometer palladium-silver (Pd/Ag) ultra-thin film was used for hydrogen gas sensing. The atomic ratio of Pd: Ag was 3:1, the thin film was evaporated on the optical glass, the Pd/Ag alloy could increase the life and provide the stability of the sensing film. The artificial neutral network was used for processing the data collected from the optical fiber bundle hydro-gen sensor, which could enhance the measuring accuracy, at the same time, the intrinsic and extrinsic influences were eliminated mainly. Experimental results and numerical simulation show the training method available, a linear precision of 0.1% for the optical hydrogen sensor is achieved.

  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. 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. PMID:27454194

  8. 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.

  9. 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

  10. Propiedades de aleaciones Ag-Pd para usos odontológicos

    OpenAIRE

    Basualto, J.; Barceló, C.; Gaete, A.

    1996-01-01

    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...

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

    Science.gov (United States)

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

    2014-03-01

    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 size-selection and relax process via the coalescence or aggregation of the primary nanoclusters. The as-prepared PdAg can be supported on the carbon black without any post-treatment, which exhibited high electro-oxidation activity towards methanol oxidation under alkaline media. More importantly, carbon-supported Pd80Ag20 nanoparticles reveal distinctly superior activities for the methanol oxidation, even if compared with commercial Pt/C electro-catalyst. It is concluded that the enhanced activity is dependant on the unique twinning structure with heterogeneous phase due to the dominating coalescence growth in EG ternary system.

  12. Permeability of hydrogen isotopes through Pd-Ag membrane

    International Nuclear Information System (INIS)

    This paper represents the permeabilities, diffusion coefficients and isotope effects for hydrogen and deuterium through Pd-25 wt.% Ag alloy tubes The feed gas H2 or D2 flowing into the permeation cell was preheated before it reached to the outer surface of the permeation tube made of palladium-silver alloy. Permeation time lag method could be successfully carried out with the present apparatus to measure both permeability and diffusion coefficient. The square-root pressure dependence for the permeation of hydrogen isotopes was observed. The observed systematic temperature dependence indicates that the approximation of the Arrhenius' relation was effective within this experimental conditions. Some tendency of permeation fluxes in relation to the reciprocal temperature, 1/T, was seen. The permeability ratio was larger than the square root of isotopic mass ratio, and it decreased with temperature rise. On the contrary, the diffusion coefficient ratio was much smaller than the square root of isotopic mass ratio. (Kato, T.)

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

    International Nuclear Information System (INIS)

    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)2](NO3)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 chemical resistivity

  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. The role of Pd in the transport of Ag in SiC

    Energy Technology Data Exchange (ETDEWEB)

    Olivier, E.J., E-mail: jolivier@nmmu.ac.za [Centre for High Resolution Transmission Electron Microscopy, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Neethling, J.H. [Centre for High Resolution Transmission Electron Microscopy, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa)

    2013-01-15

    This paper presents results in support of a newly proposed transport mechanism to account for the release of Ag from intact TRISO particles during HTR reactor operation. The study reveals that the migration of Ag in polycrystalline SiC can occur in association with Pd, a relatively high yield metallic fission product. The migration takes place primarily along grain boundary routes, seen in the form of distinct Pd, Ag and Si containing nodules. Pd is known to rapidly migrate to the SiC and iPyC interface within TRISO particles during operation. It has been shown to chemically corrode the SiC to form palladium silicides. These palladium silicides are found present along SiC grain boundaries in nodule like form. It is suggested that Ag penetrates these nodules together with the palladium silicide, to form a Pd, Ag and Si solution capable of migrating along SiC grain boundaries over time.

  16. The role of Pd in the transport of Ag in SiC

    International Nuclear Information System (INIS)

    This paper presents results in support of a newly proposed transport mechanism to account for the release of Ag from intact TRISO particles during HTR reactor operation. The study reveals that the migration of Ag in polycrystalline SiC can occur in association with Pd, a relatively high yield metallic fission product. The migration takes place primarily along grain boundary routes, seen in the form of distinct Pd, Ag and Si containing nodules. Pd is known to rapidly migrate to the SiC and iPyC interface within TRISO particles during operation. It has been shown to chemically corrode the SiC to form palladium silicides. These palladium silicides are found present along SiC grain boundaries in nodule like form. It is suggested that Ag penetrates these nodules together with the palladium silicide, to form a Pd, Ag and Si solution capable of migrating along SiC grain boundaries over time.

  17. Preparation and characterization of metallic supported thin Pd-Ag membranes for hydrogen separation

    OpenAIRE

    Fernandez, Ekain; Medrano, Jose Antonio; Melendez, Jon; Parco, Maria; Viviente, J.L.; van Sint Annaland, Martin; Gallucci, Fausto; Pacheco Tanaka, David A.

    2015-01-01

    This paper reports the preparation and characterization of thin-film (4-5 µm thick) Pd-Ag metallic supported membranes for high temperature applications. Various thin film membranes have been prepared by depositing a ceramic interdiffusion barrier layer prior to the simultaneous Pd-Ag electroless plating deposition. Two deposition techniques for ceramic layers (made of zirconia and alumina) have been evaluated: atmospheric plasma spraying and dip coating of a powder suspension. Initially, the...

  18. 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.

  19. 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.

  20. 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

    [Single Bond]Ag alloys. A van Hove singularity near the Fermi level of the 7% Rh[Single Bond]Pd alloy has a profound effect on DeltaB. Our results are consistent with the measurements of Foner and McNiff, but detailed comparison is difficult since DeltaB is of the same order as the experimental uncertainty...

  1. Research on the secondary electron yield of TiZrV-Pd thin film coatings

    Science.gov (United States)

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

    2016-09-01

    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 absorption ability and prolonging the lifetime of TiZrV film, which will be of great value in the design of beam screen for Super Proton-Proton Collider (SPPC).

  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. 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.

  4. 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.

  5. 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.

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

    Science.gov (United States)

    Wang, Guizhen; Fang, Wei; Ye, Chen; Hu, Hanhua; Fa, Zhenzong; Yi, Jiu; Liao, Wan-qing

    2016-01-01

    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. PMID:27271376

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

    Science.gov (United States)

    Zhang, Chao; Chen, Mei; Wang, Guizhen; Fang, Wei; Ye, Chen; Hu, Hanhua; Fa, Zhenzong; Yi, Jiu; Liao, Wan-Qing

    2016-01-01

    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. PMID:27271376

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Asymmetric AgPd-AuNR heterostructure with enhanced photothermal performance and SERS activity

    Science.gov (United States)

    Zhang, Han; Liu, Zeke; Kang, Xiaolin; Guo, Jun; Ma, Wanli; Cheng, Si

    2016-01-01

    Most as-reported nanostructures through galvanic replacement reactions are still symmetric hollow structures, until now. Asymmetric structures fabricated through a galvanic replacement reaction have been rarely reported. However, asymmetric heterostructures can generally lead to new intriguing properties through asymmetric synergistic coupling. Here, we report a simple synthesis of an asymmetric one-ended AgPd bimetal on Au nanorods (AuNR) by combining a galvanic replacement reaction with an Ostwald ripening process. The morphological evolution from a nanodumbbell to a dandelion structure is thoroughly investigated. The unique asymmetric AgPd-AuNR heterostructures possess the required plasmonic performance and avoid strong damping caused by the poor plasmonic metal Pd, resulting in a superior photothermal heating performance and enhanced SERS sensitivity for in situ monitoring of a catalytic reaction compared with the symmetric counterparts.Most as-reported nanostructures through galvanic replacement reactions are still symmetric hollow structures, until now. Asymmetric structures fabricated through a galvanic replacement reaction have been rarely reported. However, asymmetric heterostructures can generally lead to new intriguing properties through asymmetric synergistic coupling. Here, we report a simple synthesis of an asymmetric one-ended AgPd bimetal on Au nanorods (AuNR) by combining a galvanic replacement reaction with an Ostwald ripening process. The morphological evolution from a nanodumbbell to a dandelion structure is thoroughly investigated. The unique asymmetric AgPd-AuNR heterostructures possess the required plasmonic performance and avoid strong damping caused by the poor plasmonic metal Pd, resulting in a superior photothermal heating performance and enhanced SERS sensitivity for in situ monitoring of a catalytic reaction compared with the symmetric counterparts. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07333b

  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. 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.

  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. 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

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

    International Nuclear Information System (INIS)

    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 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 are responsible for the improvement of electrocatalytic activity and durability. The results obtained in this work are different from those previous reports, in which alloy walls with hollow interiors are usually formed. This work provides a new and simple method for synthesizing novel bimetallic core–shell structure with a hollow interior, which can be applied as high-performance catalysts for the electro-oxidation of formic acid. (paper)

  20. Electron-spectroscopy study of YbXCu4 (X=Ag,Au,Pd)

    International Nuclear Information System (INIS)

    We have studied the electronic structure of the heavy-electron compounds YbXCu4, with X = Ag,Au,Pd, using x-ray photoemission and bremsstrahlung isochromat spectroscopies. Consistent with other evidence of small Kondo temperatures, we find that Yb in this system is nearly trivalent and that Kondo features in the Yb 4f BIS spectra are either absent or weak

  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

    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...

  2. 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...

  3. 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.

  4. 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

  5. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyo-Joong; Kim, Han-Ki, E-mail: imdlhkkim@khu.ac.kr [Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, 1 Seocheon-dong, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of); Lee, Hyun Hwi [Pohang Accelerator Laboratory, POSTECH, Jigokro-127beon-gil, Nam-gu, Pohang 790-784 (Korea, Republic of); Kal, Jinha; Hahn, Jungseok [Future Technology Research Group, Kolon Central Research Park, 154 Mabukro, Giheung-ku, Yongin-si, Kyunggi-do, 16910 (Korea, Republic of)

    2015-10-15

    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.

  7. 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.

  8. Surface characterization of Pd/Ag23 wt% membranes after different thermal treatments

    International Nuclear Information System (INIS)

    Hydrogen permeation measurements of 1.5-10 μm thick Pd/Ag23 wt% membranes before and after thermal treatments at 300 deg. C in air (both sides) or in the temperature range 300-450 deg. C in N2 (feed side) and Ar (permeate side) were performed. Accompanying changes in surface topography and chemical composition were subsequently investigated by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) depth profiling. For a 2 μm thick membrane, the surface roughness increased for all annealing temperatures applied, while a temperature of 450 deg. C was required for an increase in roughness of both membrane surfaces to occur for the 5 μm membrane. The thickest membrane, of 10 μm, showed changed surface roughness on one side of the membrane only and a slight decrease in hydrogen permeance after all heat treatments in N2/Ar. X-ray photoelectron spectroscopy investigations performed after treatment and subsequent permeation measurements revealed segregation of silver to the membrane surfaces for all annealing temperatures applied. In comparison, heat treatment at 300 deg. C in air resulted in significantly increased hydrogen permeance accompanied by increasing surface roughness. Upon exposure to oxygen, Pd segregates to the surface to form a 2-3 nm thick oxide layer (PdO), with more complex segregation behavior after subsequent reduction and permeance measurements in pure hydrogen. The available permeance data for the Pd/Ag23 wt% membranes after heat treatment in air at 300 deg. C is found to depend linearly on the inverse membrane thickness, implying bulk limited hydrogen permeation for thicknesses down to 1.5-2.0 μm.

  9. Evolution of a defect structure of Pd-Ag alloys during tritium exposure

    Energy Technology Data Exchange (ETDEWEB)

    Tebus, V. E-mail: tebus@bochvar.ru; Rivkis, L.; Dmitrievskaia, E.; Arutunova, G.; Golikov, I.; Ryazantseva, N.; Filin, V.; Kapychev, V.; Bulkin, V

    2002-12-01

    Pd-Ag alloys, a material for palladium diffuser of the ITER fuel clean-up system, were investigated after long-term usage exposition in tritium. Nucleation and evolution of the alloy structure defects as a result of a radiogenic helium-3 accumulation have been examined using electron microscopy, positron annihilation and X-ray analysis. The types of helium containing defects and their characteristics were determined. The early stage of helium bubbles forming was observed. It was shown that the simple defect concentration decreased slowly and helium-3 bubble sizes and concentration increased during the tritium exposure.

  10. 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...

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Magnetic properties of ZnS doped with noble metals (X = Ru, Rh, Pd, and Ag)

    Science.gov (United States)

    Tan, Zhiyun; Xiao, Wenzhi; Wang, Lingling; Yang, Youchang

    2012-12-01

    Density functional theory calculations are carried out to study the electronic structures and magnetic properties in zinc-blende structure ZnS doped with nonmagnetic noble metals (X = Ru, Rh, Pd, and Ag). Results show robust magnetic ground states for X-doped ZnS. The total magnetic moments are about 2.0, 3.0, and 2.0 μB per supercell for the Ru-, Rh-, and Pd-doped ZnS, respectively. As the atomic number of X element increases, the local magnetic moment tends toward delocalize and the hybridization between X-4d and S-3p states become stronger. This trend is strongly related to the difference in electronegativity between the substitutional X and the cation in the ZnS host. For Ag-doped ZnS, both non-spin- and spin-polarized calculations yield nearly equal total energy. The substitution of Zn in ZnS parent material by the nonmagnetic 4d transition-metals may lead to half-metallic ferromagnetism which stems from the hybridization between X-4d and S-3p states and could be attributed to a double-exchange mechanism. Curie temperature values are estimated using mean-field approximation.

  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. A green method to prepare Pd-Ag nanoparticles supported on reduced graphene oxide and their electrochemical catalysis of methanol and ethanol oxidation

    Science.gov (United States)

    Li, Lingzhi; Chen, Mingxi; Huang, Guanbo; Yang, Nian; Zhang, Li; Wang, Huan; Liu, Yu; Wang, Wei; Gao, Jianping

    2014-10-01

    Bimetallic palladium-silver nanoparticles (NPs) supported on reduced oxide graphene (RGO) with different Pd/Ag ratios (Pd-Ag/RGO) were prepared by an easy green method which did not use any additional reducing agents or a dispersing agent. During the process, simultaneous redox reactions between AgNO3, K2PdCl4 and graphene oxide (GO) led to bimetallic Pd-Ag NPs. The morphology and composition of the Pd-Ag/RGO were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis and Raman spectroscopy. Cyclic voltammetry and chronoamperometry were used to investigate the electrochemical activities and stabilities of these Pd-Ag/RGO catalysts for the electro-oxidation of methanol and ethanol in alkaline media. Among the different Pd/Ag ratios, the Pd-Ag (1:1)/RGO had the best catalytic activities and stability. So it is a promising catalyst for direct alcohol fuel cell applications.

  18. 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.

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

    Science.gov (United States)

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

    2015-12-01

    TiZrV film is mainly applied in the ultra-high vacuum pipes of storage rings. Thin film coatings of palladium, which are added onto the TiZrV film to increase the service life of nonevaporable getters and enhance H2 pumping speed, were 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 films were about 0.42-1.3 nm and 8.5-18.25 nm respectively. It was found that the roughness of TiZrV films is small, about 2-4 nm, but for Pd film it is large, about 17-19 nm. The PP At. % of Pd in TiZrV/Pd films varied from 86.84 to 87.56 according to the XPS test results. Supported by National Natural Science Funds of China (11205155) and Fundamental Research Funds for the Central Universities (WK2310000041)

  20. Electrospun polyacrylonitrile nanofibers supported Ag/Pd nanoparticles for hydrogen generation from the hydrolysis of ammonia borane

    Science.gov (United States)

    Tong, Yan; Lu, Xiaofeng; Sun, Weining; Nie, Guangdi; Yang, Liu; Wang, Ce

    2014-09-01

    A high-performance hydrogen generation system based on the electrospun polyacrylonitrile (PAN)/Ag/Pd composite nanofibers, which were prepared by microwave reducing the electrospun PAN/AgNO3 nanofibers and followed by a replacement reaction has been demonstrated. The morphology of the as-prepared PAN/Ag/Pd composite nanofibers and the metal nanoparticles on the fibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution TEM (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements. It has been demonstrated that the obtained PAN/Ag/Pd composite nanofibers possess fine morphology and high catalytic activities for H2 generation from aqueous solution of ammonia borane (NH3BH3, AB). The H2 generation test exhibited that the catalyst had excellent catalytic activity (with turnover frequency (TOF) of 377.2 mol H2 h-1 (mol Pd)-1), good recycle stability and easy-separation from the reaction system. This new kind of nanofibers possesses great potential application for the new clean energy development.

  1. 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.

  2. 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.

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

    OpenAIRE

    Wang, Jie; Zhang, Bo; 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 spect...

  4. 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.

  5. Bimetallic Ag-Pd nanoparticles-decorated graphene oxide: a fascinating three-dimensional nanohybrid as an efficient electrochemical sensing platform for vanillin determination

    International Nuclear Information System (INIS)

    Highlights: • A 3D Ag-Pd/GO nanohybrid was fabricated via a green and in situ chemical route. • Ag-Pd/GO shows excellent electro-catalytic properties for the oxidation of vanillin. • The 3D hybrid-based sensor shows excellent performances for the vanillin detection. • This proposed method was successfully used to detect vanillin in children’s snacks. - Abstract: In this work, a fascinating hybrid based on Ag-Pd bimetallic nanoparticles-decorated graphene oxide (Ag-Pd/GO) has been successfully synthesized by a green and in situ chemical reduction strategy. The resultant hybrid was particularly characterized by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, ultraviolet-visible spectroscopy and electrochemical techniques. The morphological results illustrate that Ag-Pd nanoparticles in microspheric appearances are highly dispersed and embedded on the GO layers, resulting in a rough surface and three-dimensional (3D) microstructure with a high Ag-Pd content in the matrix. The as-synthesized 3D Ag-Pd/GO hybrid displays distinctly enhanced electrocatalytic activity for the vanillin oxidation in comparison with that of the monometal-decorated GO, revealing a synergistic effect of the matrix GO and the doped bimetallic Ag-Pd. Therefore, the Ag-Pd/GO composite can be used as an enhanced electrochemical sensing platform for the sensitive determination of vanillin, and the fabricated sensor displays a wide detection range of 0.02–45 μmol dm−3, low detection limit of 5 nmol dm−3 and satisfactory recoveries between 98.8 % and 103.5 %. All the results demonstrate that the 3D hybrids integrated graphene with bimetallic nanoparticles are promising candidates for the development of high-performance electrochemical sensors

  6. Novel PdAgCu ternary alloy as promising materials for hydrogen separation membranes: Synthesis and characterization

    Science.gov (United States)

    Tarditi, Ana M.; Cornaglia, Laura M.

    2011-01-01

    The use of the sequential electroless plating method allowed us to obtain the PdAgCu ternary alloy on top of dense stainless steel (SS) 316 L disks. The XRD analysis indicated that initially the nucleation of the two phases of the alloy (FCC and BCC) takes place, but the FCC/BCC ratio increases with the annealing time at 500 °C in H 2 stream. After 162 h, the film contained only the FCC phase, which presents promising properties to be applied in the synthesis of hydrogen selective membranes. SEM cross-section results showed that a dense, continuous, defect-free film was deposited on top of the SS support, and the EDS data indicated that no significant gradient was present on the thickness of the film. XPS and LEIS allowed us to determine that Cu and Ag surface segregation takes place after annealing up to 500 °C/5 days. In the top-most surface layer, Ag enrichment takes place as determined by ARXPS experiments which can be the result of the lower surface tension of Ag compared to that of Cu and Pd. Increasing the annealing temperature results in an increase of the Ag surface segregation while the Cu concentration in the top-most surface layer decreases.

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

    International Nuclear Information System (INIS)

    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

  8. 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.

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

    OpenAIRE

    Mallikarjuna N. Nadagouda; Varma, Rajender S.

    2008-01-01

    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 a...

  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. Vacuum properties of TiZrV non-evaporable getter films [for LHC vacuum system

    CERN Document Server

    Benvenuti, Cristoforo; Costa-Pinto, P; Escudeiro-Santana, A; Hedley, T; Mongelluzzo, A; Ruzinov, V; Wevers, I

    2001-01-01

    Sputter-deposited thin films of TiZrV are fully activated after 24 h "in situ" heating at 180 degrees C. This activation temperature is the lowest of some 18 different getter coatings studied so far, and it allows the use of the getter thin film technology with aluminium alloy vacuum chambers, which cannot be baked at temperatures higher than 200 degrees C. An updated review is given of the most recent results obtained on TiZrV coatings, covering the following topics: influence of the elemental composition and crystal structure on activation temperature, discharge gas trapping and degassing, dependence of pumping speed and surface saturation capacity on film morphology, ageing consequent to activation-air-venting cycles and ultimate pressures. Furthermore, the results obtained when exposing a coated particle beam chamber to synchrotron radiation in a real accelerator environment (ESRF Grenoble) are presented and discussed. (13 refs).

  13. Effects of Binary Mixture of Yb2O3-La2O3 on Pd/Ag Co-Deposition by Electroless Plating

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The binary mixture of Yb2O3-La2O3 was used as an additive to improve the traditional electroless plating for Pd-Ag co-deposition on the inside surface of a porous ceramic tube. The main attention were paid to investigating the effects of Yb2O3-La2O3 on Pd-Ag co-deposition rate, plating temperature, Ag content in film and Pd/Ag reduction potentials. The experimental results show that the co-deposition rate is increased by 63%, the plating temperature is decreased by 10~20 ℃ for obtaining the same co-deposition rate and the Ag content in film basically remains unchangeable when Yb2O3-La2O3 is added into the traditional electroless plating solution. The experiment also shows that Pd/Ag reduction potentials basically remain unchangeable with the binary rare earths based on the electrochemical mathematical models An inorganic composite membrane with alloy film of 76.8(mol)% Pd-23.2(mol)% Ag and the thickness of 7.7 μm on the porous ceramic tube was prepared and the permeation fluxes of hydrogen and nitrogen through the membrane are 8.65×10-3 and 1.92×10-6 m3·m-2·s-1 at 350 ℃ and 0.3 MPa respectively.

  14. 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.

  15. Facile Synthesis of Ag Nanorods with No Plasmon Resonance Peak in the Visible Region by Using Pd Decahedra of 16 nm in Size as Seeds.

    Science.gov (United States)

    Luo, Ming; Huang, Hongwen; Choi, Sang-Il; Zhang, Chao; da Silva, Robson Rosa; Peng, Hsin-Chieh; Li, Zhi-Yuan; Liu, Jingyue; He, Zhike; Xia, Younan

    2015-10-27

    This article describes a seed-mediated approach to the synthesis of Ag nanorods with thin diameters and tunable aspect ratios. The success of this method is built upon our recent progress in the synthesis of Pd decahedra as uniform samples, together with controllable sizes. When used as a seed, the Pd decahedron could direct the deposition of Ag atoms along the 5-fold axis to generate a nanorod, with its diameter being determined by the lateral dimension of the seed. We were able to generate Ag nanorods with uniform diameters down to 20 nm. Under the conditions we used for growth, symmetry breaking occurred as the Ag atoms were only deposited along one side of the Pd decahedral seed to generate a Ag nanorod with the Pd seed being positioned at one of its two ends. We also systematically investigated the localized surface plasmon resonance (LSPR) properties of the Ag nanorods. With the transverse mode kept below 400 nm, the longitudinal mode could be readily tuned from the visible to the near-infrared region by varying the aspect ratio. As an important demonstration, we obtained Ag nanorods with no LSPR peak in the visible spectrum (400-800 nm), which are attractive for applications related to the fabrication of touchscreen displays, solar films, and energy-saving smart windows. PMID:26372854

  16. 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

  17. Studies of the AgM5N45N4.5 spectrum of disordered Ag0.5Pd0.5 alloy by Auger photoelectron coincidence spectroscopy (APECS)

    International Nuclear Information System (INIS)

    Full text: The Auger electron emission process from solids is very complex, with a range of intrinsic processes producing intensity in final spectra. These processes can include the basic Auger process, initial- and final-states, shake-up/off and Coster-Kronig (CK) processes. Auger Photoelectron Coincidence Spectroscopy (APECS) is a technique to detect the Auger electron only when the 'initial' photoelectron also is detected. By counting those Auger electrons that arrive in coincidence with a photoelectron of certain binding energy, the initial state is uniquely determined, thus controlling the magnitude of various satellites of the Auger spectrum. AxPd1-x is a disordered alloy. XPS spectra indicated that the FWHM of Ag 3d5/2 increases from 0.56 eV in pure Ag to 0.77 eV in Ag0.5Pd0.5. The disorder broadening of the Ag 3d core line in AgPd is due to the spread of local potentials in the atomic cores arising from the effects of charge transfer. In this study, an effect of disorder broadening of the core level photoelectron line on the Ag MVV Auger spectra in random substituted Ag0.5Pd0.5 alloy has been investigated by APECS. Data were collected for the AgM5V45V45 Auger line in coincidence with Ag 3d photoelectron lines. It is shown that the broadening of the AgM5V45V45 line is directly associated with the presence of disorder broadening of the Ag 3d5/2 photoelectron line

  18. 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.

  19. 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.

  20. Development of Pd-Ag Compostie Membrane for Separation of Hydrogen at Elevated Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Shamsuddin Ilias

    2009-02-28

    Pd-based membrane reactor offers the possibility of combining reaction and separation in a single operation at high temperatures to overcome the equilibrium limitations experienced in conventional reactor configurations. In this project to develop a defect-free and hermally-stable Pd-film on microporous stainless steel (MPSS) support for H2-separation and membrane reactor applications, the electroless plating process was revisited with an aim to improve the membrane morphology. Specifically, this study includes; (a) an improvement f activation step using Pulse Laser Deposition (PLD), (b) development of a novel surfactant induced electroless plating (SIEP) for depositing robust Pd-film on microporous support, and (c) application of Pd-membrane as membrane reactor in steam methanol reforming (SMR) reactions.

  1. Secondary Electron Yield Measurements of TiN Coating and TiZrV Getter Film

    CERN Document Server

    Le Pimpec, F; Kirby, R E; Pivi, M

    2003-01-01

    In the beam pipe of the positron Main Damping Ring (MDR) of the Next Linear Collider (NLC), ionization of residual gases and secondary electron emission give rise to an electron cloud which can cause the loss of the circulating beam. One path to avoid the electron cloud is to ensure that the vacuum wall has low secondary emission yield and, therefore, we need to know the secondary emission yield (SEY) for candidate wall coatings. We report on SEY measurements at SLAC on titanium nitride (TiN) and titanium-zirconium-vanadium (TiZrV) thin sputter-deposited films, as well as describe our experimental setup.

  2. 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...

  3. Structure and properties of EuTSb (T = Cu, Pd, Ag, Pt, Au) and YbIrSb

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Trinath; Schellenberg, Inga; Eul, Matthias; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2011-07-01

    The equiatomic antimonides EuTSb (T = Cu, Pd, Ag, Pt, Au) and YbIrSb were synthesized from the elements in sealed tantalum tubes in an induction furnace. The samples were investigated by powder X-ray diffraction and the structures were refined on the basis of single crystal X-ray diffractometer data: ZrBeSi type, P6{sub 3}/mmc, a = 450.7(5), c = 853.2(7) pm, wR2 = 0.032, 273 F{sup 2} values, 8 variables for EuCuSb, a = 474.9(1), c = 829.4(3) pm, wR2 = 0.028, 166 F{sup 2} values, 8 variables for EuAgSb, a = 467.1(2), c = 848.8(3) pm, wR2 = 0.042, 162 F{sup 2} values, 8 variables for EuAuSb, and TiNiSi type, space group Pnma, a = 762.5(3), b = 469.1(1), c = 792.1(1) pm, wR2 = 0.046, 670 F{sup 2} values, 20 variables for EuPdSb, and a = 700.7(1), b = 444.68(8), c = 781.3(1) pm, wR2 = 0.075, 592 F{sup 2} values, 20 variables for YbIrSb. The structures are ordered superstructure variants of the aristotype AlB{sub 2}3 with planar T{sub 3}Sb{sub 3} hexagons in EuTSb (T = Cu, Ag, Au) and puckered T{sub 3}Sb{sub 3} hexagons in EuTSb (T = Pd, Pt) and YbIrSb. TiNiSi type EuPtSb was characterized via powder data: a = 759.8(3), b = 465.4(3), c = 791.4(3) pm. Temperature dependent magnetic susceptibility measurements indicate antiferromagnetic ordering for all compounds. The samples were additionally characterized by {sup 121}Sb and {sup 151}Eu Moessbauer spectra. (orig.)

  4. 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.

  5. Traces of Z2 vortices in CuCrO2, AgCrO2, and PdCrO2

    International Nuclear Information System (INIS)

    The spin-spin relaxation of the two-dimensional triangular lattice antiferromagnets CuCrO2, AgCrO2, and PdCrO2 is investigated by electron spin resonance spectroscopy. The data proof excellent agreement with very recent predictions for the Z2-vortex ordering scenario in triangular Heisenberg antiferromagnets derived by Okubo and Kawamura. (author)

  6. Symmetry character of collective states in 104Pd populated in the EC-β+ decay of 104Ag

    International Nuclear Information System (INIS)

    The states of 104Pd, populated in the EC-β+ decay of the ground (Jπ=5+) and metastable (Jπ=2+) states of 104Ag, have been investigated in the framework of the proton-neutron interacting boson model, extending a previous analysis to take into account the newly appeared experimental data. All positive-parity states up to an excitation energy of 3 MeV and spin in the range J=1-6, fed by more than 0.3% in the decay of the parent nucleus, have been considered. As a result, strong evidence has been found for interpreting most of these states as states of collective nature having a quite pure full- or mixed-symmetry character and, in particular, for identifying the 1+ level at 2276 keV as the lowest 1+ mixed-symmetry state. (orig.)

  7. 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.

  8. 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.

  9. Thermal cyclic test for Sn-4Ag-0.5Cu solders on high P Ni/Au and Ni/Pd/Au surface finishes

    Directory of Open Access Journals (Sweden)

    M.A. Azmah Hanim

    2015-12-01

    Full Text Available In electronic packaging, the reliability of the interconnection changes with the surface finish and the type of solders being used. Thermal cycling is one method of reliability assessment. In thermal cycling experiments, the strain state is simplified by soldering together regular shaped pieces of materials with different coefficients of thermal expansion and exposing the joint to repeated fluctuations of temperature within a certain range. Thus, this study focuses on the intermetallic evolution of Sn-4Ag-0.5Cu on Ni/Au and Ni/Pd/Au surface finishes with thermal cycling up to 1000 cycles with the range of temperature varying from 10 to 80 °C. Sandwich samples were prepared by placing solder balls of Sn-4Ag-0.5Cu between two substrates of two different surface finishes: Ni/Au and Ni/Pd/Au. Optical microscope and FESEM (Field emission scanning electron microscope were used to analyze the samples. From the study, it was observed that the intermetallic changes from (Cu, Ni6Sn5 to (Ni, Cu3Sn4 after 1000 thermal cycles for Ni/Au. These changes promote the formation of cracks at the solder joint because of the different mechanical properties between Ni-Sn based intermetallic and Cu-Sn intermetallics. However, for the Ni/Pd/Au surface finishes, no cracks formed after thermal cycling up to 1000 cycles. This shows that the reliability of the solder joint is higher for Ni/Pd/Au surface finishes in this experiment. Based on these results, it can be concluded that the reliability of the Ni/Pd/Au surface finishes with Sn-4Ag-0.5Cu solders is higher within the given condition of this research.

  10. 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.

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

    Science.gov (United States)

    Porobova, Svetlana; Markova, Tat'jana; Klopotov, Vladimir; Klopotov, Anatoliy; Loskutov, Oleg; Vlasov, Viktor

    2016-01-01

    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.

  12. 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. PMID:27269809

  13. 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.

  14. Preparation and thermal treatment of Pd/Ag composite membrane on a porous α-alumina tube by sequential electroless plating technique for H2 separation

    Institute of Scientific and Technical Information of China (English)

    E.Navaei Alvar; M.Reza Golmohammadi; M.Rezaei; H.Navaei Alvar; A.Mardanloo; S.Habibzad Nouhian; M.Didari

    2008-01-01

    Pd/Ag/α-Al2O3 composite membranes were prepared by sequential electroless plating technique. The prepared membranes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spec-troscopy, and inductively coupled plasma atomic emission spectroscopy techniques (ICP-AES). Effects of annealing time, Ag content, and air treatment on the hydrogen permeation flux and morphology of the alloys were investigated. The results of the investigation showed that the prepared type of tube had a good potential as substrate for membrane preparation. In addition, a uniform defect-free alloy was prepared by annealing at 550 ℃ in H2 atmosphere. The permeation results showed an increase in H2 permeation flux by increasing the Ag content and the annealing time. In addition, the air treatment of the prepared membranes at 400 ℃ for 1 h changed the morphology of the alloy and substantially enhanced the hydrogen flux.

  15. The crystal structures of jaguéite, Cu2Pd3Se4, and chrisstanleyite, Ag2Pd3Se4

    DEFF Research Database (Denmark)

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

    2006-01-01

    The crystal structure of jaguéite, ideally Cu2Pd3Se4, monoclinic, a 5.672(5), b 9.909(9), c 6.264(6) Å, ß 115.40(2)º, space group P21/c, has been solved by direct methods and refi ned to an R1 index of 5.52% for 956 unique refl ections measured with MoK X-radiation on a P-4 Bruker diffractometer...... equipped with a CCD area-detector. The crystal structure of chrisstanleyite, ideally Ag2Pd3Se4, monoclinic a 5.676(2), b 10.342(4), c 6.341(2) Å, ß 114.996(4)º, space group P21/c, has been solved by direct methods and refi ned to an R1 index of 8.3% for 1203 unique refl ections measured with MoK X...

  16. Evaluation of Ti-Zr-V (NEG) Thin Films for their pumping speed and pumping Capacity

    International Nuclear Information System (INIS)

    Deposition of NEG thin films onto the interior walls of the vacuum chambers is an advanced technique to convert a vacuum chamber from a gas source to an effective pump. These films offer considerably large pumping speed for reactive gases like CO, H2 etc. A UHV compatible pumping speed measurement system was developed in-house to measure the pumping speed of NEG coated chambers. To inject the fixed quantity of CO and H2 gas in pumping speed measurement set-up a calibrated leak was also developed. Stainless steel chambers were sputter coated with thin film of Ti-Zr-V getter material using varied parameters for different compositions and thickness. Pumping capacity which is a function of sorbed gas quantities was also studied at various activation temperatures. In order to optimize the activation temperature for maximum pumping speed for CO and H2, pumping speeds were measured at room temperature after activation at different temperatures. The experimental system detail, pumping performance of the NEG film at various activation temperatures and RGA analysis are presented.

  17. 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.

  18. Adsorption of Pd, Pt, Cu, Ag, and Au monomers on NiAl(110) surface: a comparative study from DFT calculations.

    Science.gov (United States)

    San-Miguel, Miguel A; Amorim, Edgard P M; da Silva, E Z

    2014-08-01

    First principles calculations based on periodic density functional theory (DFT) have been used to investigate the structural, energetic and electronic properties of different transition metal atoms (Pd, Pt, Cu, Ag, and Au) on the NiAl(110) surface at low coverages (0.08 and 0.25 monolayer). All adatoms prefer to adsorb on 4-fold coordinated sites interacting with two Al and two Ni atoms and forming polar and covalent bonds, respectively. The calculated negative work function changes are explained by the effect of positive surface image created after adsorption, which induces the polarization of the negatively charged adsorbates. Consequently, for metals with similar electronegativity as Ni (Ag and Cu), this polarization effect becomes more significant and leads to larger negative work function changes, but the charge transferred is small. PMID:24219765

  19. Comparison of Ti-Zr-V nonevaporable getter films deposited using alloy or twisted wire sputter-targets

    International Nuclear Information System (INIS)

    A comparison of the performance of nonevaporable getter (NEG) films deposited using two different types of targets has been made to find the one that has the best pumping properties. For the first time, the NEG coating was deposited using a preformed Ti-Zr-V alloy target. The NEG film characterization and pumping properties have been studied in comparison with a film deposited using the commonly used three-wire twisted target. It was demonstrated that the alloy target produces a NEG coating with uniform composition both laterally and in depth. The composition of the film was found to be the same as the target. Film topography and microstructure with 5 nm grain sizes were found to be the same for both targets. The main result is that the activation temperature of the NEG coating deposited using the Ti-Zr-V alloy target is 160 deg. C, which is 20 deg. C lower than for NEG coatings deposited using three twisted wires.

  20. 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.

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

    International Nuclear Information System (INIS)

    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.

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

    OpenAIRE

    Abrikosov, I. A.; Skriver, Hans Lomholt

    1993-01-01

    We present an efficient technique for calculating surface properties of random alloys based on the coherent-potential approximation within a tight-binding linear-muffin-tin-orbitals basis. The technique has been applied in the calculation of bulk thermodynamic properties as well as (001) surface 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 exp...

  3. Henry's Law Constant for Hydrogen in Li/H{sub 3}BO{sub 3} solution using a Pd-Ag Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun-Hee; Lee, Deok-Hyun; Hur, Do-Haeng [KAERI, Daejeon (Korea, Republic of)

    2015-05-15

    The dissolved hydrogen concentration in PWRs has been controlled within the range of 25 - 50cc (STP)/kg-H{sub 2}O. It is well known that the dissolved hydrogen leads to primary water stress corrosion cracking (PWSCC), general corrosion of the primary structural materials, higher radiation fields, and deposit build up on the fuel rods in PWRs. Therefore, the optimization of the hydrogen concentration in the RCS is regarded as one of several effective approaches to manage the material integrity and reduction of the radiation sources in the primary circuit. During PWR operation, the hydrogen concentrations are controlled by varying hydrogen over pressures of a volume control tank (VCT). However, as the primary water flows from the VCT into the RCS, the temperature, system pressure, and solution chemistry in the RCS can affect the hydrogen concentration. In order to predict the content of the hydrogen partial pressure which affects the structural materials, it is needed to measure and monitor the hydrogen partial pressure accurately. In this paper, we fabricated a Pd-25wt.%Ag alloy hydrogen sensor to measure hydrogen partial pressures directly at high temperatures and high pressures. From the measured data, we determined the Henry's constants for various fields' applications. The hydrogen partial pressures were measured using a Pd-Ag hydrogen sensor in the 2 ppm Li and 1200 ppm B solution within the temperature and pressure ranges of 290 - 330 .deg. C and 2000 - 2900 psia, respectively. The Henry's constants were determined from the measured data.

  4. Henry's Law Constant for Hydrogen in Li/H3BO3 solution using a Pd-Ag Sensor

    International Nuclear Information System (INIS)

    The dissolved hydrogen concentration in PWRs has been controlled within the range of 25 - 50cc (STP)/kg-H2O. It is well known that the dissolved hydrogen leads to primary water stress corrosion cracking (PWSCC), general corrosion of the primary structural materials, higher radiation fields, and deposit build up on the fuel rods in PWRs. Therefore, the optimization of the hydrogen concentration in the RCS is regarded as one of several effective approaches to manage the material integrity and reduction of the radiation sources in the primary circuit. During PWR operation, the hydrogen concentrations are controlled by varying hydrogen over pressures of a volume control tank (VCT). However, as the primary water flows from the VCT into the RCS, the temperature, system pressure, and solution chemistry in the RCS can affect the hydrogen concentration. In order to predict the content of the hydrogen partial pressure which affects the structural materials, it is needed to measure and monitor the hydrogen partial pressure accurately. In this paper, we fabricated a Pd-25wt.%Ag alloy hydrogen sensor to measure hydrogen partial pressures directly at high temperatures and high pressures. From the measured data, we determined the Henry's constants for various fields' applications. The hydrogen partial pressures were measured using a Pd-Ag hydrogen sensor in the 2 ppm Li and 1200 ppm B solution within the temperature and pressure ranges of 290 - 330 .deg. C and 2000 - 2900 psia, respectively. The Henry's constants were determined from the measured data

  5. 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

  6. 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.

  7. 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.

  8. Characterization and Evaluation of Ti-Zr-V Non-evaporable Getter Films Used in Vacuum Systems

    Science.gov (United States)

    Ferreira, M. J.; Seraphim, R. M.; Ramirez, A. J.; Tabacniks, M. H.; Nascente, P. A. P.

    Among several methods used to obtain ultra-high vacuum (UHV) for particles accelerators chambers, it stands out the internal coating with metallic films capable of absorbing gases, called NEG (non-evaporable getter). Usually these materials are constituted by elements of great chemical reactivity and solubility (such as Ti, Zr, and V), at room temperature for oxygen and other gases typically found in UHV, such as H2, CO, and CO2. Gold and ternary Ti-Zr-V films were produced by magnetron sputtering, and their composition, structure, morphology, and aging characteristics were characterized by energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), field emission gun sc anning electronmicroscopy (FEG-SEM), atomic force microscopy (AFM), high resolution transmission electron microscopy (HRTEM). The comparison between the produced films and commercial samples indicated that the desirable characteristics depend on the nanometric structure of the films and that this structure is sensitive to the heat treatments.

  9. Influence of the noble metals (Pd, Au, Ag) in the thermoluminescent signal induced by radiation in the ZrO2

    International Nuclear Information System (INIS)

    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

  10. 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.

  11. 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)

  12. CO adsorption on Ni, Pd, Cu and Ag deposited on MgO, CaO, SrO and BaO: Density functional calculations

    International Nuclear Information System (INIS)

    The adsorption properties of CO molecules adsorbed on Ni, Pd, Cu and Ag atoms deposited on O2-, F and F+ sites of MgO, CaO, SrO and BaO terrace surfaces have been studied by means of density functional calculations and embedded cluster model. The examined clusters were embedded in the simulated Coulomb fields that closely approximate the Madelung fields of the host surfaces. The adsorption properties of CO have been analyzed with reference to the basicity of the oxide support, bond order conservation energy, pairwise and non-pairwise additivity, associative adsorption, electrostatic potentials, and orbital interactions. CO adsorption on an oxide support is drastically enhanced when CO is adsorbed on a metal deposited on this support. A dramatic change is found, and explained, when one compares the CO binding energy to O2- and F sites. The formation of a strong bond at the support-metal interface has a considerable consequence on the metal-CO binding energy. The binding of CO is dominated by the metal-CO pairwise additive term, and the non-additivity term increases with increasing the basicity of the support. While the classical contributions to the electrostatic interactions are quite similar for the deposited metals, they are quite dissimilar when going from defect-free to defect-containing surfaces. The adsorption properties correlate linearly with the basicity and energy gaps of the oxide support where the electrostatic potential generated by the oxide modifies the physical and chemical properties of the adsorbed metal and therefore its reactivity versus the CO adsorbate.

  13. LaMgX and CeMgX (X = Ga, In, Tl, Pd, Ag, Pt, Au) with ZrNiAl type structure - A systematic view on electronic structure and chemical bonding

    Science.gov (United States)

    Matar, Samir F.; Etourneau, Jean; Pöttgen, Rainer

    2015-05-01

    The intermetallic magnesium compounds LaMgX and CeMgX (X = Ga, In, Tl, Pd, Ag, Pt, Au) crystallize with the hexagonal ZrNiAl type structure, space group P 6 bar 2 m , with full Mg-X ordering. From density functional theory calculations carried out exemplarily on four representative compounds: LaMgX and CeMgX with X = Ga, Pd, significant differences were traced out as to the magnetism arising only for the Ce series leading to identify CeMgGa as an antiferromagnet in its ground state, in agreement with experiment. The bulk module magnitudes show the trend of harder transition metal based ternaries and the cohesive energies favor the X = Pd compounds versus X = Ga ones. Such features were clarified by examining the properties of chemical bonding which exhibit more directional bonds thanks to the Pd d states. Rationalizing the trends of charge transfers, negatively charged triel and transition element atoms are observed. The resulting chemical pictures assign these compounds as gallides and palladides.

  14. 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...

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. Electrical properties of thin-film structures formed by pulsed laser deposition of Au, Ag, Cu, Pd, Pt, W, Zr metals on n-6H-SiC crystal

    International Nuclear Information System (INIS)

    Diode structures with ideality factors of 1.28-2.14 and potential barriers from 0.58 to 0.62 eV on the semiconductor side were formed by pulsed laser deposition of Au, Ag, Cu, Pd, Pt, W, and Zr metal films on n-6H-SiC crystal without epitaxial layer preparation. A high density of surface acceptor and donor states was formed at the metal-semiconductor interface during deposition of the laser-induced atomic flux, which violated the correlation between the potential barrier height and metal work function. The barrier heights determined from characteristic currents and capacitance measurements were in quite good agreement. For the used low-resistance semiconductor and contact elements, the sizes of majority carrier (electron) depletion regions were determined as 26-60 nm.

  20. Nanocrystalline Pd alloy films coated by electroless deposition.

    Science.gov (United States)

    Strukov, G V; Strukova, G K; Batov, I E; Sakharov, M K; Kudrenko, E A; Mazilkin, A A

    2011-10-01

    The structures of palladium and palladium alloys thin films deposited from organic electrolytes onto metallic substrates by electroless plating method have been investigated. The coatings are dense, pore-free 0.005-1 microm thick films with high adhesive strength to the substrate surface. EDX, XRD, SEM and TEM methods were used to determine the composition and structure of alloy coatings of the following binary systems: Pd-Au, Pd-Ag, Pd-Ni, Pd-Pb, and ternary system Pd-Au-Ni. The coatings of Pd-Au, Pd-Ag and Pd-Ni have a solid solution structure, whereas Pd-Pb is intermetallic compound. It has been found that the deposited films consist of nanocrystalline grains with sizes in the range of 11-35 nm. Scanning and transmission electron microscopy investigations reveal the existence of clusters formed by nanocrystalline grains. The origin for the formation of nanocrystalline structures of coating films is discussed. PMID:22400291

  1. Full factorial design applied to the synthesis of Pd-?Ag nanobars by the polyol method and the perspective for ethanol oxidation

    OpenAIRE

    Carrera-Cerritos, Raul; Ponce De Leon, Carlos; Ledesma-Garcia, J.; Fuentes-Ramirez, R.; Arriaga, L. G.

    2014-01-01

    Full factorial design methodology was applied to the synthesis and optimization of Pd–Ag nanobars using the polyol process as the reducer. The concentration of Br? ions, the temperature and the reaction time were selected as factors to study, whereas the yield (% nanobars) was the response to be analyzed. The nanoparticles were characterized by X-ray diffraction, energy-dispersive X-ray spectroscopy, transmission electron microscopy, high-resolution transmission electron microscop...

  2. Excitation energies, radiative and autoionization rates, dielectronic satellite lines and dielectronic recombination rates for excited states of Ag-like W from Pd-like W

    International Nuclear Information System (INIS)

    Energy levels, radiative transition probabilities and autoionization rates for [Kr]4d94fnl (n = 4-9), [Kr]4d95l'nl (n = 5-9) and [Kr]4d96l'nl (n = 6-7) states in Ag-like tungsten (W27+) are calculated using the relativistic many-body perturbation theory method, the multiconfiguration relativistic Hebrew University Lawrence Livermore Atomic Code and the Hartree-Fock-relativistic method. Branching ratios relative to the first threshold and intensity factors are calculated for satellite lines, and dielectronic recombination (DR) rate coefficients are determined for the singly excited [Kr]4d10nl (n = 4-9) states. The total DR rate coefficient is derived as a function of electron temperature. These atomic data are important in the modelling of N-shell radiation spectra of heavy ions generated in various collision as well as plasma experiments. The tungsten data are particularly important for fusion application.

  3. Cross sections for proton-induced reactions on Pd isotopes at energies relevant for the gamma process

    CERN Document Server

    Dillmann, I; Domingo-Pardo, C; Käppeler, F; Marganiec, J; Uberseder, E; Giesen, U; Heiske, A; Feinberg, G; Hentschel, D; Hilpp, S; Leiste, H; Rauscher, T; Thielemann, F -K

    2011-01-01

    Proton-activation reactions on natural and enriched palladium samples were investigated via the activation technique in the energy range of E_p=2.75 MeV to 9 MeV, close to the upper end of the respective Gamow window of the gamma process. We have determined cross sections for 102Pd(p,gamma)103Ag, 104Pd(p,gamma)105Ag, and 105Pd(p,n)105Ag, as well as partial cross sections of 104Pd(p,n)104Ag^g, 105Pd(p,gamma)106Ag^m, 106Pd(p,n)106Ag^m, and 110Pd(p,n)110Ag^m with uncertainties between 3% and 15% for constraining theoretical Hauser-Feshbach rates and for direct use in gamma-process calculations.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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

    2013-03-01

    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.

  9. 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

  10. 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.

  11. 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.

  12. Fabrication and Formation Mechanism of Ag Nanoplate-Decorated Nanofiber Mats and Their Application in SERS.

    Science.gov (United States)

    Jia, Peng; Chang, Jiao; Wang, Jianqiang; Zhang, Pan; Cao, Bing; Geng, Yuting; Wang, Xiuxing; Pan, Kai

    2016-01-01

    We report a new simple method to fabricate a highly active SERS substrate consisting of poly-m-phenylenediamine/polyacrylonitrile (PmPD/PAN) decorated with Ag nanoplates. The formation mechanism of Ag nanoplates is investigated. The synthetic process of the Ag nanoplate-decorated PmPD/PAN (Ag nanoplates@PmPD/PAN) nanofiber mats consists of the assembly of Ag nanoparticles on the surface of PmPD/PAN nanofibers as crystal nuclei followed by in situ growth of Ag nanoparticles exclusively into nanoplates. Both the reducibility of the polymer and the concentration of AgNO3 are found to play important roles in the formation and the density of Ag nanoplates. The optimized Ag nanoplates@PmPD/PAN nanofiber mats exhibit excellent activity and reproducibility in surface-enhanced Raman scattering (SERS) detection of 4-mercaptobenzoic acid (4-MBA) with a detection limit of 10(-10)  m, making the Ag nanoplates@PmPD/PAN nanofiber mats a promising substrate for SERS detection of chemical molecules. In addition, this work also provides a design and fabrication process for a 3D SERS substrate made of a reducible polymer with noble metals. PMID:26395245

  13. 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.

  14. 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

    2015-12-01

    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. PMID:26399897

  15. Measuring the pD of heavy water solutions

    International Nuclear Information System (INIS)

    Analogously to the chemistry of aqueous solutions, a chemistry of heavy water solutions can be developed and, correspondingly, by measuring the pD value - the activity of deuterium ions - the behavior of these solutions can be characterized. The cells for measurement of pD can be achieved similarly to the cell for pH, by using Ag/AgCl electrodes and thus a device for measuring the acid-basic balance in a heavy water solution can be made by measuring the electromotive force and establishing a corresponding pD scale. A strict comparison between pD and pH is not possible since both scales are conventional. Values of paD and paH for phosphate solutions of the same molar concentration in heavy and light water, respectively, differs constantly between them by 0.6 units. Such differences in various solutions, using glass electrodes and control calomel electrodes, allowed getting a more exact value (0.41 pH units) for solutions of molar concentration, with a standard deviation of 0.031. Thus, a pD value can be obtained with a pH-meter with glass and control calomel electrodes by applying the correction relation, plus 0,41 units. We have done such determinations by using a domestic made control electrode of the type HC Ag/AgCl pH=7. Determinations with sodium carbonate and iron and sodium chloride solutions in light and heavy water, at the same concentrations, were carried out. The values recorded from the pH-meter for heavy water solutions are lower than the pH values by 0.407 units, so that this value must be added to the pH readings to get the pD values. The standard deviation of these determinations was 0.012 pH units

  16. 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.

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

    International Nuclear Information System (INIS)

    The corrosion and tarnish behavior of a dental casting Pd-25Ag-18Cu-12Au alloy in 0.1% Na2S 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% Na2S solution

  18. PD-1 Blockage Reverses Immune Dysfunction and Hepatitis B Viral Persistence in a Mouse Animal Model

    Science.gov (United States)

    Tzeng, Horng-Tay; Tsai, Hwei-Fang; Liao, Hsiu-Jung; Lin, Yi-Jiun; Chen, Lieping; Chen, Pei-Jer; Hsu, Ping-Ning

    2012-01-01

    Persistent hepatitis B viral (HBV) infection results in chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). Recent studies in animal models of viral infection indicate that the interaction between the inhibitory receptor, programmed death (PD)-1, on lymphocytes and its ligand (PD-L1) play a critical role in T-cell exhaustion by inducing T-cell inactivation. High PD-1 expression levels by peripheral T-lymphocytes and the possibility of improving T-cell function by blocking PD-1-mediated signaling confirm the importance of this inhibitory pathway in inducing T-cell exhaustion. We studied T-cell exhaustion and the effects of PD-1 and PD-L1 blockade on intrahepatic infiltrating T-cells in our recently developed mouse model of HBV persistence. In this mouse animal model, we demonstrated that there were increased intrahepatic PD-1-expressing CD8+ and CD4+ T cells in mice with HBV persistence, but PD-1 upregulation was resolved in mice which had cleared HBV. The Intrahepatic CD8+ T-cells expressed higher levels of PD-1 and lower levels of CD127 in mice with HBV persistence. Blockade of PD-1/PD-L1 interactions increased HBcAg-specific interferon (IFN)-γ production in intrahepatic T lymphocytes. Furthermore, blocking the interaction of PD-1 with PD-L1 by an anti-PD-1 monoclonal antibody (mAb) reversed the exhausted phenotype in intrahepatic T lymphocytes and viral persistence to clearance of HBV in vivo. Our results indicated that PD-1 blockage reverses immune dysfunction and viral persistence of HBV infection in a mouse animal model, suggesting that the anti-PD-1 mAb might be a good therapeutic candidate for chronic HBV infection. PMID:22761734

  19. PD-1 blockage reverses immune dysfunction and hepatitis B viral persistence in a mouse animal model.

    Directory of Open Access Journals (Sweden)

    Horng-Tay Tzeng

    Full Text Available Persistent hepatitis B viral (HBV infection results in chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC. Recent studies in animal models of viral infection indicate that the interaction between the inhibitory receptor, programmed death (PD-1, on lymphocytes and its ligand (PD-L1 play a critical role in T-cell exhaustion by inducing T-cell inactivation. High PD-1 expression levels by peripheral T-lymphocytes and the possibility of improving T-cell function by blocking PD-1-mediated signaling confirm the importance of this inhibitory pathway in inducing T-cell exhaustion. We studied T-cell exhaustion and the effects of PD-1 and PD-L1 blockade on intrahepatic infiltrating T-cells in our recently developed mouse model of HBV persistence. In this mouse animal model, we demonstrated that there were increased intrahepatic PD-1-expressing CD8+ and CD4+ T cells in mice with HBV persistence, but PD-1 upregulation was resolved in mice which had cleared HBV. The Intrahepatic CD8+ T-cells expressed higher levels of PD-1 and lower levels of CD127 in mice with HBV persistence. Blockade of PD-1/PD-L1 interactions increased HBcAg-specific interferon (IFN-γ production in intrahepatic T lymphocytes. Furthermore, blocking the interaction of PD-1 with PD-L1 by an anti-PD-1 monoclonal antibody (mAb reversed the exhausted phenotype in intrahepatic T lymphocytes and viral persistence to clearance of HBV in vivo. Our results indicated that PD-1 blockage reverses immune dysfunction and viral persistence of HBV infection in a mouse animal model, suggesting that the anti-PD-1 mAb might be a good therapeutic candidate for chronic HBV infection.

  20. Two new class III G6PD variants [G6PD Tunis (c.920A>C: p.307Gln>Pro) and G6PD Nefza (c.968T>C: p.323 Leu>Pro)] and overview of the spectrum of mutations in Tunisia.

    Science.gov (United States)

    Benmansour, Ikbel; Moradkhani, Kamran; Moumni, Imen; Wajcman, Henri; Hafsia, Raouf; Ghanem, Abderraouf; Abbès, Salem; Préhu, Claude

    2013-02-01

    We screened 423 patients referred to our laboratory after hemolysis triggered by fava beans ingestion, neonatal jaundice or drug hemolysis. Others were asymptomatic but belonged to a family with a history of G6PD deficiency. The determination of enzymatic activity using spectrophotometric method, revealed 293 deficient (143 males and 150 females). The molecular analysis was performed by a combination of PCR-RFLP and DNA sequencing to characterize the mutations causing G6PD deficiency. 14 different genotypes have been identified : G6PD A(-) (376A>G;202G>A) (46.07%) and G6PD Med (33.10%) were the most common variants followed by G6PD Santamaria (5.80%), G6PD Kaiping (3.75%), the association [c.1311T and IVS11 93c] (3.75%), G6PD Chatham (2.04%), G6PD Aures (1.70%), G6PD A(-) Betica (0.68%), the association [ 376G;c.1311T;IVS11 93c] (0.68%), G6PD Malaga, G6PD Canton and G6PD Abeno respectively (0.34%). Two novel missense mutations were identified (c.920A>C: p.307Gln>Pro and c.968T>C: p.323 Leu>Pro). We designated these two class III variants as G6PD Tunis and G6PD Nefza. A mechanism which could account for the defective activity is discussed. PMID:22963789

  1. Automated system for selective fission product separations; decays of /sup 113 -115/Pd

    Energy Technology Data Exchange (ETDEWEB)

    Meikrantz, D.H.; Gehrke, R.J.; McIsaac, L.D.; Baker, J.D.; Greenwood, R.C.

    1981-01-01

    A microcomputer controlled radiochemical separation system has been developed for the isolation and study of fission products with half-lives of approx. >= 10 s. The system is based upon solvent extraction with three centrifugal contactors coupled in series, which provides both rapid and highly efficient separations with large decontamination factors. This automated system was utilized to study the radioactive decays of /sup 113 -115/Pd via solvent extraction of the Pd-dimethylglyoxime complex from /sup 252/Cf fission products. As a result of this effort, ..gamma..-rays associated with the decay of approx. equal to 90-s sup(113,113m)Pd, 149-s /sup 114/Pd and 47-s /sup 115/Pd have been identified. The isotopic assignments to each of these Pd radioactivities have been confirmed from observation of the growth and decay curves of their respective Ag daughters. In addition, previously unreported Ag ..gamma..-rays have been assigned; one to the decay of 69-s /sup 113/Ag, and two to the decay of 19-s /sup 115/Ag.

  2. 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

  3. Structural optimization of Ag–Pd clusters based on different potential parameterizations

    International Nuclear Information System (INIS)

    Graphical abstract: The stable structures of bimetallic Ag–Pd clusters by density-functional-theory-fitted parameters and experimental-fitted parameters are compared based on Gupta potential by using adaptive immune optimization algorithm. Highlights: ► Global optimization of Ag–Pd clusters based on different parameters is performed. ► DFT-fitted parameters and experimental-fitted parameters are used. ► The differences of structures and excess energies are compared. ► The atomic distribution of Ag and Pd atoms in both Ag–Pd clusters is different. - Abstract: The putative stable structures of bimetallic Ag–Pd clusters are investigated. Gupta potential is applied to describe the interatomic interactions in Ag–Pd clusters. Experimental-fitted parameters and density-functional-theory (DFT)-fitted parameters are used to determine the lowest energy structures. Global optimization of AgmPdn (m + n = 15) and Ag3mPd38−3m (m = 1–12) clusters is performed using adaptive immune optimization algorithm (AIOA). The growth rules of Ag–Pd clusters for both sets of parameterizations are studied, and the differences of structures and excess energies are compared. With the order parameters adopted to show the atomic distribution in the clusters, it is shown that for both parameterized clusters silver atoms have strong tendencies towards segregating at the surface of the structures. However, for both potentials, the atomic distribution of Ag and Pd atoms in Ag–Pd clusters is different because of the geometrical and symmetrical difference.

  4. Design of Pd-based membrane reactor for gas detritiation

    International Nuclear Information System (INIS)

    The development of a Pd-based membrane reactor to be applied in processes for tritium removal from various gaseous streams of tokamak systems has been carried out. In particular, the membrane reactor has been designed for decontaminating soft housekeeping wastes of JET. This membrane reactor consists of Pd-Ag permeator tube fixed in a finger-like mode into a stainless steel shell. The feed stream (gases to be detritiated) is fed inside the membrane lumen where the isotopic exchange takes place on to a catalyst bed while pure hydrogen (protium) is sent in countercurrent mode in the shell side. The feed stream consists of 200 Ncm3 min-1 of helium with 10% of tritiated water (tritium content 1.11 x 108 Bq h-1). The membrane reactor design has been based on a simplified calculation model which takes into consideration the very low tritium content of the gas to be processed and the complete oxidation of the tritiated species in the feed stream. The model considers a tubular Pd-Ag membrane divided into finite elements where the mass balances are performed according to both the thermodynamic equilibrium reactions and permeation rates through the membrane of the hydrogen isotopes. The reactor model has permitted to verify that a Pd-Ag commercial tube of diameter 10 mm, length 500 mm and wall thickness 0.150 mm is capable to attain a decontamination factor larger than 10. A new mechanical design of the Pd membrane reactor has been also developed: especially, harmful mechanical stresses of the long permeator tube consequent to the hydrogenation and thermal cycling has been avoided. Furthermore, an innovative effective heating system of the membrane has been also applied.

  5. 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

  6. Synthesis and Characterization of a New TRIPHOS Ligand Derivative and the Corresponding Pd(II) Complexes

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-12-01

    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.

  7. Spectroscopy of exotic 121,123,125Ag produced in fragmentation reactions

    International Nuclear Information System (INIS)

    Excited states in the neutron-rich 121,123,125Ag were studied via the fragmentation of a 136Xe beam at 120MeV/nucleon in a thick 9Be target. The levels in 121Ag were populated in the β decay of 121Pd while those assigned to 123,125Ag were identified via isomer spectroscopy. The transitions identified in 121Ag are consistent with the γ -rays reported in 117,119Ag. The newly observed transitions were placed in the level schemes of 123,125Ag based on the analysis of γ - γ coincidences and the systematics. We attribute the onset of isomerism in the 123,125Ag isotopes to the drop in energy of the negative-parity levels similar to the 5 - state in the even-even Cd cores. The proposed level scheme for 125Ag is well described by the NuShellX shell model calculations. (orig.)

  8. PD-1, PD-L1, PD-L2 expression in the chordoma microenvironment

    Science.gov (United States)

    Mathios, Dimitrios; Ruzevick, Jacob; Jackson, Christopher M.; Xu, Haiying; Shah, Sagar; Taube, Janis M.; Burger, Peter C.; McCarthy, Edward F.; Quinones-Hinojosa, Alfredo; Pardoll, Drew M.

    2015-01-01

    Chordomas are rare malignant tumors that are postulated to arise from remnants of the notochord. Currently, the interaction between chordomas and the host immune system is poorly understood. The checkpoint protein, PD-1 is expressed by circulating lymphocytes and is a marker of activation and exhaustion. Its ligands, PD-L1 (B7-H1, CD274) and PD-L2 (B7-DC, CD273), are expressed on a variety of human cancers; however this pathway has not been previously reported in chordomas. We used flow cytometric and RT-PCR analysis in three established primary and recurrent chordoma cell lines (U-CH1, U-CH2, and JHC7) as well as immunohistochemical analysis of chordoma tissues from 10 patients to identify and localize expression of PD-1 pathway proteins. PD-1 ligands are not constitutively expressed by chordoma cells, but their expression is induced in the setting of pro-inflammatory cytokines in all cell lines examined. In paraffin embedded tissues, we found that tumor infiltrating lymphocytes expressed PD-1 in 3/6 cases. We also found that, although chordoma cells did not express significant levels of PD-L1, PD-L1 expression was observed on tumor-infiltrating macrophages and tumor infiltrating lymphocytes. Our study suggests that PD-1, PD-L1, and PD-L2 are present in the microenvironment of a subset of chordomas analyzed. Future studies are needed to evaluate the contribution of the PD-1 pathway to the immunosuppressive microenvironment of chordomas. PMID:25349132

  9. Preparation, characterization, and photocatalytic activity of porous AgBr@Ag and AgBrI@Ag plasmonic photocatalysts

    Science.gov (United States)

    Yang, Fan; Tian, Baozhu; Zhang, Jinlong; Xiong, Tianqing; Wang, Tingting

    2014-02-01

    Porous AgBr@Ag and AgBrI@Ag plasmonic photocatalysts were synthesized by a multistep route, including a dealloying method to prepare porous Ag, a transformation from Ag to AgBr and AgBrI, and a photo-reduction process to form Ag nanoparticles on the surface of AgBr and AgBrI. It was found that the porous structure kept unchanged during Ag was transferred into AgBr, AgBrI, AgBr@Ag, and AgBrI@Ag. Both porous AgBr@Ag and porous AgBrI@Ag showed much higher visible-light photocatalytic activity than cubic AgBr@Ag for the degradation of methyl orange, which is because the interconnected pore channels not only provide more reactive sites but also favor the transportation of photo-generated electrons and holes. For AgBrI@Ag, AgBrI solid solution formed at the interface of AgBr and AgI, and the phase junction can effectively separate the photo-generated electrons and holes, favorable to the improvement of photocatalytic activity. The optimal I content for obtaining the highest activity is ∼10 at.%.

  10. 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.

  11. 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.

  12. 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.

  13. Current-induced spin polarization in transition metals and Bi/Ag bilayers observed by spin-polarized positron beam

    Science.gov (United States)

    Zhang, Hongjun; Yamamoto, Shunya; Fukaya, Yuki; Maekawa, Masaki; Li, Hui; Kawasuso, Atsuo; Seki, Takeshi; Saitoh, Eiji; Takanashi, Koki; JAEA Team; Tohoku Team

    2015-03-01

    Current-induced spin polarization (CISP) on the outermost surfaces of Au, Cu, Pt, Pd, Ta, and W films were studied by spin-polarized positron beam (SPPB). The Au and Cu surfaces showed no significant CISP. In contrast, the Pt, Pd, Ta, and W films exhibited large CISP (3 ~ 15% per charge current of 105 A/cm2) and the CISP of Ta and W were opposite to those of Pt and Pd. The sign of the CISP obeys the same rule in spin Hall effect suggesting that the spin-orbit coupling is mainly responsible for the CISP. The outermost spin poalrization of Bi/Ag/Al2O3andAg/Bi/Al2O3 (charge currents directly connected to Ag layers) were probed by SPPB. The opposite outermost spin polarization of Bi/Ag/Al2O3andAg/Bi/Al2O3 clarified the charge-to-spin conversion in Bi/Ag bilayers. Nevertheless, the magnitudes of the outermost spin polarization of Bi(0.3 ~5)/Ag(25)/Al2O3 (numbers in parentheses denote thickness in nm) and Ag(25 ~500)/Bi(8)/Al2O3 decrease exponentially with increasing Bi thickness and Ag thickness, respectively. This provides probably the first direct evidence for spin diffusion mechanism. Financial support from JSPS Kakenhi Grant 24310072.

  14. 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.

  15. 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.

  16. AGS experiments -- 1991, 1992, 1993

    International Nuclear Information System (INIS)

    This report contains: (1) FY 1993 AGS schedule as run; (2) FY 1994--95 AGS schedule; (3) AGS experiments ≥ 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

  17. 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.

  18. AGS experiments - 1994, 1995, 1996

    International Nuclear Information System (INIS)

    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

  19. Clinical and prognostic significance of PD-1 and PD-L1 expression in sarcomas.

    Science.gov (United States)

    Paydas, Semra; Bagir, Emine Kilic; Deveci, Mehmet Ali; Gonlusen, Gulfiliz

    2016-08-01

    Programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) are new targets in cancer immunotherapy in recent years. The aim of this study is to evaluate the PD-1/PD-L1 expressions in sarcomas and to determine association between PD-1/PD-L1 expressions and clinical/pathological properties in some sarcoma subtypes. Formalin-fixed, paraffin-embedded tissue samples from 65 cases with sarcomas were analyzed. Immunohistochemical staining was performed to detect the PD-1 and PD-L1 expressions in tumor tissue and microenvironment, separately. PD-1 expression in tumor tissue and microenvironment was detected in 11 (17 %) and 8 (12 %) cases, respectively. PD-L1 expression in tumor tissue and microenvironment was detected in 19 (29 %) and 20 cases (30 %), respectively. None of the 5 Ewing sarcomas involving bone showed PD-1/PD-L1 expression, while 2 of 3 cases with Ewing sarcomas involving soft tissue showed PD-1 and PD-L1 expression. Among 5 cases with Kaposi sarcoma, four showed PD-1 and/or PD-L1 expression in tumor or microenvironment. PD-1/PD-L1 expressions were detected 3 of 6 cases with pleomorphic sarcoma, 2 of 4 cases with peripheral nerve sheath tumors and 1 of 4 cases with synovial sarcoma. Interestingly, strongest PD-1/PD-L1 expressions in our study group were detected in 2 sarcoma cases with the history of giant cell tumor. PD-1 and PD-L1 expressions are up to 30 % of the cases with sarcomas. It may be rational to target programmed death pathway in Kaposi sarcoma, pleomorphic sarcoma and peripheral nerve sheath tumors. Strong expression of PD-1/PD-L1 in cases with previous giant cell bone tumor has been found to be interesting and must be studied in giant cell tumor samples. PMID:27421997

  20. Electrodeposition of dendritic Pd nanoarchitectures on n-GaN(0001): nucleation and electrocatalysis for direct formic acid fuel cells

    International Nuclear Information System (INIS)

    Dendritic Pd nanoarchitectures were electrochemically deposited on single-crystal n-GaN(0001) by cyclic voltammetry and employed as anode electrocatalyst for direct formic acid fuel cells. The Pd deposition on n-GaN(0001) was found to commence at 0.2 V vs. Ag/AgCl without underpotential deposition process and follow the typical instantaneous nucleation in large overpotential region. High-resolution transmission electron microscope images revealed that numerous small branches were formed around the trunk of dendritic structures and grew along the <111> directions. The as-obtained dendritic Pd nanoarchitectures showed good catalytic performance for formic acid and the oxidation peak potential appeared at 0.45 V vs. Ag/AgCl. The maximum current density and mass activity were 19.7 mA cm−1 and 904 mA mg−1, respectively, for the dendritic Pd nanocrystals obtained by cycling the potentials from -0.25 to 1.0 V for 5 times

  1. 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.

  2. 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.

  3. 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.

  4. 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...

  5. High-purity hydrogen generation in a microfabricated 23 wt % Ag-Pd membrane device integrated with 8:1 LaNi{sub 0.95}Co{sub 0.05}O{sub 3}/Al{sub 2}O{sub 3} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Wilhite, B.A.; Weiss, S.E.; Ying, J.Y.; Jensen, K.F. [Department of Chemical Engineering, Massachusetts Institute of Technology, 25 Ames Street, 66-501 Cambridge, MA 02139 (United States); Schmidt, M.A. [Department of Electrical Engineering and Computer Science, and Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2006-07-04

    Micromembranes integrating nanometer-scale Pd films with complex oxide methanol-reforming catalysts demonstrate high-purity hydrogen generation. Washcoating of an 8:1 LaNi{sub 0.95}Co{sub 0.05}O{sub 3}/Al{sub 2}O{sub 3} catalyst serves the dual purposes of preventing thin-film disintegration upon direct exposure to methanol while providing improved selectivity and conversion of methanol to hydrogen through partial oxidation. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  6. 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

  7. First-principles study of ferromagnetism in Pd-doped and Pd- Cu-codoped BN

    Science.gov (United States)

    Wang, Q.; Wang, S.; Dai, J. F.; Li, W. X.

    2016-07-01

    In this paper, we aimed at probing the ferromagnetism properties of Pd and Pd-Cu- codoped supercell BN based on the first-principles methods. The formation energy, lattice constants, energy band structures, spin density of state, energy difference between ferromagnetism (FM) and autiferromagnetism (AFM) orderings were calculated. Formation energy calculations showed that Pd atom tended to replace B atom in the supercell. Pd-doped BN exhibited a half-metallic ferromagnetic. And the ferromagnetism arised form the strong hybridization between the Pd4d and N2p state. Pd-Cu-codoped BN also displayed a half-metallic ferromagnetic. The incorporation of Pd and Pd-Cu induced some impurity energy differences between FM and AFM orderings. It also showed that FM state was the ground state, and room temperature ferromagnetism may be expected. These results pointed out the possibility of fabricating BN based on dilute magnetic semiconductors (DMS) by doping with Pd and Pd-Cu.

  8. 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.

  9. AGS experiments: 1993 - 1994 - 1995

    International Nuclear Information System (INIS)

    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

  10. 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.

  11. PD-L1-specific T cells

    DEFF Research Database (Denmark)

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

    2016-01-01

    -specific T cells that recognize both PD-L1-expressing immune cells and malignant cells. Thus, PD-L1-specific T cells have the ability to modulate adaptive immune reactions by reacting to regulatory cells. Thus, utilization of PD-L1-derived T cell epitopes may represent an attractive vaccination strategy...... 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...

  12. The AGS CNI polarimeter

    International Nuclear Information System (INIS)

    A new polarimeter is being installed in the Brookhaven AGS, based on the successful proton-carbon polarimeters in RHIC. The polarimeter will measure the left-right asymmetry for proton-carbon elastic scattering in the Coulomb-nuclear interference (CNI) region, for vertically polarized protons in the AGS. The polarimeter offers a much higher figure of merit than the existing AGS polarimeter which is based on larger angle proton-proton elastic scattering. We expect to measure the polarization in the AGS with a single or a few acceleration cycles. We also plan to measure the polarization in 2 ms bins during the AGS acceleration ramp. Multiple ramps will be necessary, probably over 30 minutes to an hour

  13. PD-1 as an Immune Modulatory Receptor

    Science.gov (United States)

    Yao, Sheng; Chen, Lieping

    2015-01-01

    Programmed cell death 1 (PD-1) is an inducible immune modulatory receptor. Upon interaction with its ligands B7 homolog 1 (PD-L1) and B7-DC (PD-L2), PD-1 plays important roles in negative regulation of T cell responses to antigen stimulation and maintaining peripheral tolerance. In addition to the inducible expression pattern on conventional T cells, PD-1 is also found on regulatory T cells, follicular T and B cells, and antigen-presenting cells including activated dendritic cells and monocytes. Therefore, PD-1 may have a much broader functionality than expected in negative regulation of multiple arms of immune responses. In addition to cancer therapy, the manipulation of PD-1 and its ligands may hold great promise for therapeutic applications also in autoimmune and infectious diseases. PMID:25098286

  14. [Perioperative Management of PD Patients].

    Science.gov (United States)

    Reichmann, H

    2016-07-01

    Both patients and caregivers but also treating physicians are concerned about complications along with surgical interventions. A major problem is abrupt cessation of anti-Parkinson medication, which leads to manifold disturbances, sometimes even to an akinetic crisis. There are several means to guarantee continuous dopaminergic stimulation even in patients that are not allowed to take medication orally before they undergo surgery. Amongst others rectally applied levodopa, amantadine infusions, and especially the use of a rotigotine patch are good means to overcome oral intake. Perioperative management is important due to the fact that in Germany alone each year more than 10 000 PD patients undergo surgery. Main reasons for this are fractures, but also elective interventions. Further emergency situations that cause treatment as an inpatient are psychosis, motoric disability, but also pneumonia and cardiovascular disturbances. In contrast PD patients suffer less often from cancer. PMID:27276074

  15. Lifetime measurements in 101Pd

    International Nuclear Information System (INIS)

    Excited states in the 101Pd nucleus were populated in the 75As(31P, 2p3n)101Pd fusion- evaporation reaction at Elab = 125 MeV. The de-excitations were investigated through in-beam gamma-ray spectroscopic techniques. The 31P beam was provided by the Pelletron- LINAC facility at TIFR, Mumbai. The 75As target of thickness 2.8 mg/cm2 was prepared by vacuum evaporation and rolled onto a 10 mg/cm2 thick Pb backing. The recoiling nuclei in the excited states were stopped within the target and the de-exciting gamma-rays were detected using the Indian National Gamma Array (INGA) consisting of 21 Compton suppressed clover detectors. Two and higher fold clover coincidence events were recorded in a fast digital data acquisition system based on Pixie-16 modules of XIA LLC

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Optical absorption engineering in stacked plasmonic Au-SiO₂-Pd nanoantennas.

    Science.gov (United States)

    Wadell, Carl; Antosiewicz, Tomasz J; Langhammer, Christoph

    2012-09-12

    The nonradiative decay of a localized surface plasmon through absorption of a captured photon and excitation of an energetic electron-hole pair is a potentially very effective way to enhance chemical reactions on metal nanoparticle surfaces, so far limited to Ag (and Au). Here we explore the possibility of efficient and spectrally widely tunable optical absorption engineering based on heterometallic optical nanoantennas. They consist of an optimized antenna element made of Au (or Ag) and a catalytically active second metallic element separated by a thin SiO(2) layer. Specifically, we find that stacked Au-SiO(2)-Pd nanodisk antennas exhibit pronounced local absorption enhancement in the catalytic Pd particle. The effect is caused by efficient power transfer from the Au disk, exhibiting a narrow low-loss resonance and acting as an antenna collecting photons, to the Pd disk due to strong coupling between the two. The Pd element thus acts as receiver that efficiently dissipates energy into electron-hole pairs owing to efficient coupling to intra and interband transitions. In fact, the energy transfer is found to be so effective that the absorption efficiency at a given wavelength can be enhanced up to 6 to 9 times, and the total absorption integrated over a wide spectral range (400-900 nm) up to 2-fold, depending on the antenna dimensions. This finding suggests a novel route toward highly efficient plasmon-enhanced catalysis on widely selectable catalytic metal particle surfaces not limited to the "classic" plasmonic metals Au and Ag. PMID:22916998

  1. 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.

  2. 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.

  3. 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.

  4. PD-1/PD-L1 blockade in cancer treatment: perspectives and issues.

    Science.gov (United States)

    Hamanishi, Junzo; Mandai, Masaki; Matsumura, Noriomi; Abiko, Kaoru; Baba, Tsukasa; Konishi, Ikuo

    2016-06-01

    Recent studies showed that tumor cells 'edit' host immunity in several ways to evade immune defenses in the tumor microenvironment. This phenomenon is called "cancer immune escape." One of the most important components in this system is an immunosuppressive co-signal (immune checkpoint) mediated by the PD-1 receptor and its ligand, PD-L1. PD-1 is mainly expressed on activated T cells, whereas PD-L1 is expressed on several types of tumor cells. Preclinical studies have shown that inhibition of the interaction between PD-1 and PD-L1 enhances the T-cell response and mediates antitumor activity. Several clinical trials of PD-1/PD-L1 signal-blockade agents have exhibited dramatic antitumor efficacy in patients with certain types of solid or hematological malignancies. In this review, we highlight recent clinical trials using anti-PD-1 or anti-PD-L1 antibodies against several types of malignancies, including a trial conducted in our department, and describe the clinical perspectives and issues regarding the PD-1/PD-L1 blockade in cancer treatment. PMID:26899259

  5. 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.

  6. Diffusion Coefficients and Activation Energies for Ag Transport through SiC

    International Nuclear Information System (INIS)

    One of the desired functions of TRISO coating is to prevent the release of fission products from inside the particle into the coolant. Among these layers, the retention of fission products is accomplished primarily by the SiC layer of the coating. These processes include oxide fuel kernel migration (via the transport of carbon from the cool to hot side); intra-layer crack formation, noble gas (Kr, Xe), Ba, Ag, Sr, Cs diffusion out of the kernel; pressure build-up due to noble gas release from the kernel and CO from released oxygen in ungettered oxide kernel; a Pd attack on SiC and noble gas, Pd, Ba, Sr, Cs, Ag, transport via bulk diffusion, grain boundaries, and cracks through the coating layers. In this paper, the measured and estimated diffusion coefficients of Ag in and/or through SiC are compared based on the following experimental methods: 1) measuring Ag diffusion through ion-implanted cubic (3C) SiC and 6H-SiC samples and annealing, 2) measuring Ag diffusion through a diffusion couple and annealing, and 3) fitting the overall integrated/fractional Ag release from a batch of TRISO fuel particle during heating after irradiation and irradiation testing. The causes of uprising Ag transport through SiC, the coating layer of TRISO fuel are complex depending on the temperature during operation or irradiation testing. Although Ag transport depends on the microstructure of SiC (such as grain boundary stoichiometry, SiC grain size and shape, the presence of free silicon, nano-cracks, etc.), neutron irradiation, irradiation temperature, Pd attack, thermal decomposition, transmutation products, layer thinning and coated particle shape, etc., Ag diffusion along the grain boundary of SiC plays a major role. Considering that the current Ag diffusion coefficient is summarized and compared from previous studies, it might also be possible that, considering the irradiation effects of SiC, the Ag retention ability of a TRISO particle somehow improves during the TRISO

  7. H-H interactions in Pd

    DEFF Research Database (Denmark)

    Christensen, O. B.; Ditlevsen, Peter; Jacobsen, Karsten Wedel;

    1989-01-01

    -medium theory to calculate total energies we show the same tendency for the short-range part of the H-H interaction when two H atoms are squeezed into a single site in Pd or PdH. At longer range (of the order a lattice constant) there is an attractive, lattice-mediated H-H interaction. On the basis...

  8. 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.

  9. TiOx thin films grown on Pd(100) and Pd(111) by chemical vapor deposition

    Science.gov (United States)

    Farstad, M. H.; Ragazzon, D.; Grönbeck, H.; Strømsheim, M. D.; Stavrakas, C.; Gustafson, J.; Sandell, A.; Borg, A.

    2016-07-01

    The growth of ultrathin TiOx (0≤x≤2) films on Pd(100) and Pd(111) surfaces by chemical vapor deposition (CVD), using Titanium(IV)isopropoxide (TTIP) as precursor, has been investigated by high resolution photoelectron spectroscopy, low energy electron diffraction and scanning tunneling microscopy. Three different TiOx phases and one Pd-Ti alloy phase have been identified for both surfaces. The Pd-Ti alloy phase is observed at the initial stages of film growth. Density functional theory (DFT) calculations for Pd(100) and Pd(111) suggest that Ti is alloyed into the second layer of the substrate. Increasing the TTIP dose yields a wetting layer comprising Ti2 + species (TiOx, x ∼0.75). On Pd(100), this phase exhibits a mixture of structures with (3 × 5) and (4 × 5) periodicity with respect to the Pd(100) substrate, while an incommensurate structure is formed on Pd(111). Most importantly, on both surfaces this phase consists of a zigzag pattern similar to observations on other reactive metal surfaces. Further increase in coverage results in growth of a fully oxidized (TiO2) phase on top of the partially oxidized layer. Preliminary investigations indicate that the fully oxidized phase on both Pd(100) and Pd(111) may be the TiO2(B) phase.

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

    KAUST Repository

    Song, HyonMin

    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.

  11. 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

  12. Geometrical Characteristics and Atomic Charge Variations of Pd(II) Complexes [Pd(L)Cl{sub 2}] with an Axial (Pd...O) Interaction

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Keun [Pusan National University, Busan (Korea, Republic of); Cho, Yong Guk; Lee, Shim Sung; Kim, Bong Gon [Gyeongsang National University, Jinju (Korea, Republic of)

    2004-01-15

    Geometrical structures of [Pd(L)Cl{sub 2}] with oxathia macrocycles have been calculated using ab initio second order Moller-Plesset (MP2) and Density Functional Theory (DFT) methods with triple zeta plus polarization (TZP) basis set level. In optimized Pd(L)Cl{sub 2} complexes, Pd(II) locates at the center surrounded by a square planar array of two sulfurs on an oxathia macrocycle and two chlorides. The endo-Pd(II) complexes with an axial (Pd...O) interaction are more stable than the exo-Pd(II) complexes without the interaction. In the endo- Pd(II) complexes, the atomic charge of the oxygen atom moves to Pd(II) via the axial (Pd...O) interaction and then, the charge transfer from Pd(II) to the S-atoms occurs stepwise via {pi}-acceptors of the empty d-orbitals

  13. AGS experiments: 1990, 1991, 1992

    International Nuclear Information System (INIS)

    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

  14. 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.

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

    KAUST Repository

    Song, HyonMin

    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.

  16. 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...

  17. Decomposition mechanism of YBa2Cu3Ox at various oxygen partial pressures and its influence on the microstructure of YBCO/Ag composites

    International Nuclear Information System (INIS)

    In a recent publication we have described a modified melt-processing of YBCO tapes produced by the doctor blade method and pressed onto the surface of AgPd ribbons. The YBCO tapes were partially melted in an inert atmosphere at relatively low temperatures of somewhat above 1000 C and after exchange of the inert gas for O2 the composites were slowly cooled down. As the result a partial alignment of c-axis of the solidified YBa2Cu3Ox-crystals and an improved behaviour of jc in magnetic fields were achieved. In this work the formation of the microstructure of YBCO/AgPd composites (20 w% Pd in the AgPd-alloy) in dependence on the melt-processing conditions was studied in more detail. For this purpose the phase relations after the heat treatment of YBa2Cu3Ox at various temperatures and in atmospheres of different O2 partial pressure have been investigated. AgPd sheathed YBCO tapes were also included in the experiments of melt processing. Preliminary attempts were performed to improve the texture and to increase the critical current density (jc) by directional solidification of YBCO tapes. (orig.)

  18. Pd-Si binary bulk metallic glass

    Institute of Scientific and Technical Information of China (English)

    YAO KeFu; CHEN Na

    2008-01-01

    Pd80+xSi20-x (x=0, 1, and 2) binary metallic glasses with the diameter ranging from 7 to 8 mm were prepared by a combination of fluxing and water quenching or air cooling. Thermal analysis results show that with increasing Si content, the glass transition temperature Tg, the initial crystallization temperature Tx and the onset crystalliza-tion temperature Tp of Pd-Si binary glassy alloys increase. Moreover, the super-cooled liquid region reaches 61 K. It indicates that Pd-Si binary alloys possess large glass forming ability, which can be greatly improved by fluxing treatment.

  19. Pd-Si binary bulk metallic glass

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Pd80+xSi20-x (x=0,1,and 2) binary metallic glasses with the diameter ranging from 7 to 8 mm were prepared by a combination of fluxing and water quenching or air cooling. Thermal analysis results show that with increasing Si content,the glass transition temperature Tg,the initial crystallization temperature Tx and the onset crystalliza-tion temperature Tp of Pd-Si binary glassy alloys increase. Moreover,the super-cooled liquid region reaches 61 K. It indicates that Pd-Si binary alloys possess large glass forming ability,which can be greatly improved by fluxing treatment.

  20. Association of PD-1, PD-1 ligands, and other features of the tumor immune microenvironment with response to anti-PD-1 therapy

    Science.gov (United States)

    Taube, Janis M.; Klein, Alison; Brahmer, Julie R.; Xu, Haiying; Pan, Xiaoyu; Kim, Jung H.; Chen, Lieping; Pardoll, Drew M.; Topalian, Suzanne L.; Anders, Robert A.

    2014-01-01

    Purpose Immunomodulatory drugs differ in mechanism-of-action from directly cytotoxic cancer therapies. Identifying factors predicting clinical response could guide patient selection and therapeutic optimization. Experimental Design Patients (N=41) with melanoma, non-small cell lung carcinoma (NSCLC), renal cell carcinoma (RCC), colorectal carcinoma or castration-resistant prostate cancer were treated on an early phase trial of anti-PD-1 (nivolumab) at one institution and had evaluable pre-treatment tumor specimens. Immunoarchitectural features including PD-1, PD-L1, and PD-L2 expression, patterns of immune cell infiltration, and lymphocyte subpopulations, were assessed for interrelationships and potential correlations with clinical outcomes. Results Membranous (cell surface) PD-L1 expression by tumor cells and immune infiltrates varied significantly by tumor type and was most abundant in melanoma, NSCLC, and RCC. In the overall cohort, PD-L1 expression was geographically associated with infiltrating immune cells (p<0.001), although lymphocyte-rich regions were not always associated with PD-L1 expression. Expression of PD-L1 by tumor cells and immune infiltrates was significantly associated with expression of PD-1 on lymphocytes. PD-L2, the second ligand for PD-1, was associated with PD-L1 expression. Tumor cell PD-L1 expression correlated with objective response to anti-PD-1 therapy, when analyzing either the specimen obtained closest to therapy or the highest scoring sample among multiple biopsies from individual patients. These correlations were stronger than borderline associations of PD-1 expression or the presence of intratumoral immune cell infiltrates with response. Conclusions Tumor PD-L1 expression reflects an immune-active microenvironment and, while associated other immunosuppressive molecules including PD-1 and PD-L2, is the single factor most closely correlated with response to anti-PD-1 blockade. PMID:24714771

  1. 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.

  2. AGS experiments - 1995, 1996 and 1997

    International Nuclear Information System (INIS)

    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

  3. 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.

  4. 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.

  5. Asymmetric magnetic proximity effect in a Pd/Co/Pd trilayer system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong-Ok; Song, Kyung Mee; Choi, Yongseong; Min, Byoung-Chul; Kim, Jae-Sung; Choi, Jun Woo; Lee, Dong Ryeol

    2016-05-06

    In spintronic devices consisting of ferromagnetic/nonmagnetic systems, the ferromagnet-induced magnetic moment in the adjacent nonmagnetic material significantly influences the spin transport properties. In this study, such magnetic proximity effect in a Pd/Co/Pd trilayer system is investigated by x-ray magnetic circular dichroism and x-ray resonant magnetic reflectivity, which enables magnetic characterizations with element and depth resolution. We observe that the total Pd magnetic moments induced at the top Co/Pd interface are significantly larger than the Pd moments at the bottom Pd/Co interface, whereas transmission electron microscopy and reflectivity analysis indicate the two interfaces are nearly identical structurally. Such asymmetry in magnetic proximity effects could be important for understanding spin transport characteristics in ferromagnetic/nonmagnetic systems and its potential application to spin devices.

  6. Toxicities of the anti-PD-1 and anti-PD-L1 immune checkpoint antibodies.

    Science.gov (United States)

    Naidoo, J; Page, D B; Li, B T; Connell, L C; Schindler, K; Lacouture, M E; Postow, M A; Wolchok, J D

    2015-12-01

    Immune checkpoint antibodies that augment the programmed cell death protein 1 (PD-1)/PD-L1 pathway have demonstrated antitumor activity across multiple malignancies, and gained recent regulatory approval as single-agent therapy for the treatment of metastatic malignant melanoma and nonsmall-cell lung cancer. Knowledge of toxicities associated with PD-1/PD-L1 blockade, as well as effective management algorithms for these toxicities, is pivotal in order to optimize clinical efficacy and safety. In this article, we review selected published and presented clinical studies investigating single-agent anti-PD-1/PD-L1 therapy and trials of combination approaches with other standard anticancer therapies, in multiple tumor types. We summarize the key adverse events reported in these studies and their management algorithms. PMID:26371282

  7. CO oxidation on PdO surfaces

    DEFF Research Database (Denmark)

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

    2010-01-01

    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...... oxidation via the Langmuir–Hinshelwood mechanism. The reaction with a surface oxygen atom has an activation energy of 0.66 eV, which is comparable to the lowest activation energies observed on metallic surfaces. However, the reaction rate may be limited by the coverage of molecular oxygen. Actually...... 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...

  8. Comparing PD results with visual inspection

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, A. [ENEL, (Italy); Stone, G.C. [Iris Power Engineering Inc., Toronto, ON (Canada)

    2005-07-01

    ENEL, the largest generator of electricity in Italy has 39,000 MW of generating capacity, of which one third is hydraulic and the remainder is from fossil sources, with no nuclear generation. The utility has 180 hydro generators, 72 steam turbine generators and 48 gas turbine generators. As the fleet of units ages, ENEL is proactive in on-line condition assessment of the generators in their system. Partial discharge (PD) sensors are used to find stator winding insulation problems. On-line PD testing was first conducted by ENEL in the 1980s on 10 hydro generators. ENEL also used devices such as the TVA corona probe during major overhauls. By the end of the 1990s ENEL started to permanently install sensors on large hydro generators that have suffered from PD in the past, and on turbogenerators installed in new and renewed plants. Since 1999, 72 generators have been equipped with the TGA-SP instrument manufactured by Iris Power Engineering. The PD sensors typically found units with severe insulation problems, but it was not possible to determine the cause of the deterioration from the PD pattern. It was suggested that more frequent testing than every 6 months may be needed. Most of the machines have relatively low PD activity, in comparison with a published database of results. All machines undergo periodic visual inspection and off-line testing. This paper summarized the comparison of PD data with known condition of the stator winding insulation. Some problems encountered with interpretation were also discussed. ENEL considers PD testing to be a powerful tool, particularly when used in combination with visual inspections. 4 refs., 14 figs.

  9. Assessment of PD Speech Anomalies @ Home

    OpenAIRE

    Khan, Taha; Westin, Jerker

    2011-01-01

    Background: Voice processing in real-time is challenging. A drawback of previous work for Hypokinetic Dysarthria (HKD) recognition is the requirement of controlled settings in a laboratory environment. A personal digital assistant (PDA) has been developed for home assessment of PD patients. The PDA offers sound processing capabilities, which allow for developing a module for recognition and quantification HKD. Objective: To compose an algorithm for assessment of PD speech severity in the home...

  10. Voestalpine AG : equity valuation

    OpenAIRE

    Shamuradov, Rustam

    2014-01-01

    Voestalpine AG is a steel-based technology and capital goods group and a world leader in the manufacture, processing, and development of sophisticated steel products. The Group supplies technology-intensive sectors, such as the automotive, railway, aviation, and energy industries. The Group had adopted the development strategy for the decade, targeting 2 billion EUR in total revenue by 2020, which is 73% higher compared to the most recent result. The strategy also implies th...

  11. Equity valuation Siemens AG

    OpenAIRE

    Silva, Bernardo Santos

    2015-01-01

    This dissertation presents an in-depth analysis and consequent equity valuation of Siemens AG. The main objective of this paper is to provide an alternative perspective of what might be the fair value of this company considering its prospects of growth, risk and position in the market. The idea that value is highly subjective is kept in mind during all this process although it is important to understand how crucial this information is to shareholders and potential investors and the necessity ...

  12. AG mod rovet

    DEFF Research Database (Denmark)

    Storm, Rasmus K.

    2010-01-01

    Den nye storsatsning, AG København, ser ud til at give dansk herrehåndbold uforholdsmæssigt stor opmærksomhed. I en tid med pengenød og forhandlinger om en kommende tv-aftale, er det rent guf for håndboldens parter. Men den nyrige aktør øger også risikoen for, at ligaen brækker midt over såvel...

  13. 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.

  14. Effect of UV laser irradiation on the hardness and structural parameters of AgxPd1−x (0.4 ≤ x ≤ 0.6) alloys

    International Nuclear Information System (INIS)

    Highlights: ► Surface hardness of AgPd alloy specimens increases with increasing number of laser shots. ► Increase in surface hardness per laser shot is maximum for Ag50Pd50. ► Surface hardness is a function of dislocation line density, which increases with increasing number of laser shots. ► Hardness profile shows a decreasing trend till a distance of 3 mm from midpoint of the laser spot. - Abstract: Strips of high-purity AgxPd1−x alloys, with x = 0.4, 0.5 and 0.6, were solution treated at 800 °C for 2 h. Specimens of each composition were then irradiated with 100, 200, 300, and 400 shots of KrF Excimer laser (maximum energy 20 mJ, wavelength 248 nm, pulse width 20 ns, repetition rate 20 Hz). For each alloy, Vickers hardness of un-irradiated and irradiated specimens was measured as a function of the number of laser shots, and was found to increase with increasing number of shots. The increase in surface hardness at the midpoint of laser irradiation spot on Ag40Pd60, Ag50Pd50, and Ag60Pd40 specimens was up to 27.6, 30.2, and 17.3%, respectively. The surface hardness profile for each irradiated specimen shows a decreasing trend till a distance of 3 mm from the midpoint of the irradiated spot. XRD study of the alloy specimens of each composition shows that the dislocation line density increases with increasing number of shots, and the surface hardness is a function of it.

  15. 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.

  16. 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.

  17. [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.

  18. Near-threshold {eta} production in the pd {yields} pd{eta} reaction

    Energy Technology Data Exchange (ETDEWEB)

    Hibou, F.; Bergdolt, A.M.; Bergdolt, G.; Bing, O.; Bouchakour, A. [Institute de Recherches Subatomiques, 67 - Strasbourg (France); Wilkin, C. [University College London, London WC1E 6BT (United Kingdom); Boivin, M. [Laboratoire National Saturne, 91191 Gif-sur-Yvette Cedex (France); Brochard, F.; Plouin, F. [Laboratoire National Saturne, 91191 Gif-sur-Yvette Cedex (France); LPNHE, Ecole Polytechnique, 91128 Palaiseau (France); Combes-Comets, M.P.; Courtat, P.; Gacougnolle, R.; Le Bornec, Y.; Reide, F.; Tatischeff, B.; Willis, N. [Institut de Physique Nucleaire, IN2P3-CNRS/Universite Paris-Sud, 91406 Orsay Cedex (France); Moalem, A. [Physics Department, Ben Gurion University, 84105 Beer Sheva (Israel)

    2000-04-01

    The total cross section of the pd{yields}pd{eta} reaction has been measured at two energies near threshold by detecting the final proton and deuteron in a magnetic spectrometer. The values are somewhat larger than expected on the basis of two simple theoretical estimates. (orig.)

  19. 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\

  20. 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.

  1. 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.

  2. 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.

  3. CTLA-4 and PD-1 Pathways

    Science.gov (United States)

    Desai, Anupam

    2016-01-01

    The cytotoxic T-lymphocyte–associated antigen 4 (CTLA-4) and programmed death 1 (PD-1) immune checkpoints are negative regulators of T-cell immune function. Inhibition of these targets, resulting in increased activation of the immune system, has led to new immunotherapies for melanoma, non–small cell lung cancer, and other cancers. Ipilimumab, an inhibitor of CTLA-4, is approved for the treatment of advanced or unresectable melanoma. Nivolumab and pembrolizumab, both PD-1 inhibitors, are approved to treat patients with advanced or metastatic melanoma and patients with metastatic, refractory non-small cell lung cancer. In addition the combination of ipilimumab and nivolumab has been approved in patients with BRAF WT metastatic or unresectable melanoma. The roles of CTLA-4 and PD-1 in inhibiting immune responses, including antitumor responses, are largely distinct. CTLA-4 is thought to regulate T-cell proliferation early in an immune response, primarily in lymph nodes, whereas PD-1 suppresses T cells later in an immune response, primarily in peripheral tissues. The clinical profiles of immuno-oncology agents inhibiting these 2 checkpoints may vary based on their mechanistic differences. This article provides an overview of the CTLA-4 and PD-1 pathways and implications of their inhibition in cancer therapy. PMID:26558876

  4. Immune responses to HBsAg conjugated to protein D of non-typeable Haemophilus influenzae in mice.

    Directory of Open Access Journals (Sweden)

    Qiudong Su

    Full Text Available Hepatitis B vaccine that contains an aluminum hydroxide adjuvant induces apoptotic death of Hepa 1-6 cells. Difficult-to-degrade chemical additives in vaccines effectively enhance vaccine immunogenicity, but also affect the host tissue. Identification of bio-molecules that are readily degraded and compatible in vivo as an adjuvant is important for vaccine research. The hapten-carrier effect suggests that stimulation of helper T (Th cells by carrier adjuvants is feasible. Protein D (PD of non-typeable Haemophilus influenzae covalently conjugated to some polysaccharide vaccines has been confirmed to convert T-cell independent (TI antigens into T-cell dependent (TD antigens, and elicit strong T-cell responses ultimately. Herein, we would substitube PD for aluminum hydroxide adjuvant in Hepatitis B vaccine.Truncated PD (amino acids 20-364 was expressed in Escherichia coli and purified by (NH42SO4 precipitation and DEAE chromatography. After evaluation of antigenicity by western blotting, PD was covalently conjugated to yeast-derived recombinant HBsAg by cross-linking with glutaraldehyde. Intramuscular immunization with the conjugate induced higher level of HBsAg-specific antibody than did HBsAg alone (p < 0.05, and was comparable to commercial Hepatitis B vaccine. During the surveillance period (days 35-105, anti-HBs titers were hold high. Moreover, the conjugated vaccine enhanced Th1 immune responses, while Th2 responses were also activated and induced an antibody response, as determined by IFN-γ ELISPOT and IgG1/IgG2a ratio assays.Recombinant truncated PD covalently conjugated to HBsAg antigen enhanced the immunogenicity of the antigen in mice simultaneously by humoral and cellular immune response, which would facilitate therapeutic hepatitis B vaccines.

  5. The atomic Fe/Ag exchange on Ag(100)

    NARCIS (Netherlands)

    Langelaar, MH; Boerma, DO; Moss, SC; Ila, D; Cammarata, RC; Chason, EH; Einstein, TL; Williams, ED

    1997-01-01

    In this paper we present a low-energy ion scattering (LEIS) study of the site exchange of Fe adatoms with Ag atoms from the Ag(100) surface. The time-of-flight (TOF) spectra obtained at low temperatures have been interpreted with a newly developed LEIS simulation program MATCH. After low temperature

  6. 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.

  7. 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.

  8. RDM lifetime measurement in 103Pd

    International Nuclear Information System (INIS)

    In 103Pd, band-termination has been observed at high spins in the yrast band. In the band-termination, angular momentum evolves from a purely collective rotation at the band-head to a pure single-particle configurations at the terminating spin and as a result the quadrupole moment or B(E2)) values along the band decrease with spin. So measuring B(E2) values with spin along the yrast band in 103Pd would not only reveal the changing nuclear shape along the yrast band, but also would help in understanding the cause of observed band termination in this nucleus. With this motivation, recoil distance lifetime measurement experiment in 103Pd nucleus has been performed at the Inter University Accelerator Centre (IUAC), New Delhi

  9. 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.

  10. PD-1 regulates extrathymic regulatory T-cell differentiation

    OpenAIRE

    Chen, Xiufen; Fosco, Dominick; Kline, Douglas E.; Meng, Liping; Nishi, Saki; Savage, Peter A.; Kline, Justin

    2014-01-01

    Regulatory T (Treg) cells and the programmed death-1/programmed death ligand-1 (PD-1/PD-L1) pathway are both critical for maintaining peripheral tolerance to self antigens. A significant subset of Treg cells constitutively expresses PD-1, which prompted an investigation into the role of PD-1/PD-L1 interactions in Treg-cell development, function and induction in vivo. The phenotype and abundance of Treg cells was not significantly altered in PD-1-deficient mice. The thymic development of polyc...

  11. Magnetic characteristics of CoPd and FePd antidot arrays on nanoperforated Al2O3 templates

    Science.gov (United States)

    Maximenko, A.; Fedotova, J.; Marszałek, M.; Zarzycki, A.; Zabila, Y.

    2016-02-01

    Hard magnetic antidot arrays show promising results in context of designing of percolated perpendicular media. In this work the technology of magnetic FePd and CoPd antidot arrays fabrication is presented and correlation between surface morphology, structure and magnetic properties is discussed. CoPd and FePd antidot arrays were fabricated by deposition of Co/Pd and Fe/Pd multilayers (MLs) on porous anodic aluminum oxide templates with bowl-shape cell structure with inclined intercellular regions. FePd ordered L10 structure was obtained by successive vacuum annealing at elevated temperatures (530 °C) and confirmed by XRD analysis. Systematic analysis of magnetization curves evidenced perpendicular magnetic anisotropy of CoPd antidot arrays, while FePd antidot arrays revealed isotropic magnetic anisotropy with increased out-of-plane magnetic contribution. MFM images of antidots showed more complicated contrast, with alternating magnetic dots oriented parallel and antiparallel to tip magnetization moment.

  12. Electrospray Mass Spectrometry Study on Polynuclear Pd (Ⅱ)and Ni (Ⅱ) Complexes of 3,6,9,16,19,22-Hexaazatricyclo [ 22.2.2.211, 14 ] triaconta-11, 13,24,26( 1 ) ,27,29-Hexaene

    Institute of Scientific and Technical Information of China (English)

    HE,Wei-Jiang(何卫江); LIU,Fang(刘芳); YE,Zhi-Feng(叶智峰); MEI,Yu-Hua(梅毓华); GUO,Zi-Jian(郭子建); ZHU,Long-Gen(朱龙根)

    2001-01-01

    Polynuclear Pd(Ⅱ) and Ni(Ⅱ) com, exes of macrocyclic polyamine 3, 6, 9, 16, 19,22-hexaazatricyclo [ 22. 2.2.211,14]-triaconta 11,13,24,26(1),27,20-hexaene (L) in solution were investigated by electrospray ionization mass spectrometry (ESIMS). For methanol solution of complexes M2LX4(M =Pd(Ⅱ) and Ni(Ⅱ), X= Cr and I-), two main clusters of peaks were observed which can be assigned to [M2LX3]+ and [M2LX2]2+. When Pd2LCl4 was treated with 2 or 4 mol of AgNO3, it gave rise formation of Pd2LCl2(NO3)2· H2O and [Pd2L(H2O) (NO3)n](4-n)+, respectively. ESMS spectra show that the dissociation of the former in the ionization process gave peaks of [Pd2LCl2]2+ and [(Pd2LCl2)NO3]+, while dissociaqtion of the later gave the peaks of[Pd2L(CH3CO2)2]2+ and {[Pd2L(CH3CO2]·(NO3)}+ in the ppresence of acetic acid. Similar species were observed for Pd2LI4 when treated with 4 mol of AgNO3. When [Pd2L.(H2O)4-n(NO3)n](4-n)+ reacted with 2 mol of oxalate anionsat 40℃, [Pd4L2(C2O4)2(NO3)2]2+ and [Pd4L2(C2O4)2·(NO3)]3+ were detected. This implies the formation of square-planar molecular box Pd4L2(C2O4)2(NO3)4 in which C2O2-4 may act as bridging ligands as confirmed by crystal structure analysis. The dissociation for and the stability of complex cations in gaseous state are also discussed.This work provides an excellent example of the usefulness of usefulness of ESIMS in the identification of metal complexes in solution.

  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. Anti–PD-1/PD-L1 therapy of human cancer: past, present, and future

    Science.gov (United States)

    Chen, Lieping; Han, Xue

    2015-01-01

    Major progress has been made toward our understanding of the programmed death-1/programmed death ligand-1 (PD-1/PD-L1) pathway (referred to as the PD pathway). mAbs are already being used to block the PD pathway to treat human cancers (anti-PD therapy), especially advanced solid tumors. This therapy is based on principles that were discovered through basic research more than a decade ago, but the great potential of this pathway to treat a broad spectrum of advanced human cancers is just now becoming apparent. In this Review, we will briefly review the history and development of anti-PD therapy, from the original benchwork to the most up-to-date clinical results. We will then focus the discussion on three basic principles that define this unique therapeutic approach and highlight how anti-PD therapy is distinct from other immunotherapeutic approaches, namely tumor site immune modulation, targeting tumor-induced immune defects, and repairing ongoing (rather than generating de novo) tumor immunity. We believe that these fundamental principles set the standard for future immunotherapies and will guide our efforts to develop more efficacious and less toxic immune therapeutics to treat human cancers. PMID:26325035

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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.

  20. 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-

  1. 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

  2. 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

  3. AGS Experiments: 1989, 1990, 1991

    International Nuclear Information System (INIS)

    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

  4. 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.

  5. 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.

  6. The clinical utility of PD-L1 testing in selecting non-small cell lung cancer patients for PD1/PD-L1-directed therapy.

    Science.gov (United States)

    Villaruz, L C; Socinski, M A

    2016-09-01

    Lung cancer is the leading cause of cancer mortality in the United States and worldwide. Long thought to be nonimmunogenic, immunotherapy in lung cancer has historically been met with disappointing results. Programmed death-1 (PD-1), and the PD-1 ligand, PD-L1, are immune checkpoint proteins that fine-tune the antigen-specific T-cell response after stimulation of the T-cell receptor and are crucial for self-tolerance. This pathway in particular is co-opted by tumors through expression of PD-L1 on the tumor cell surface and within the tumor microenvironment, allowing for direct suppression of antitumor cytolytic T-cell activity by the tumor. Indeed, induction of the PD1/PD-L1 pathway represents an adaptive immune resistance mechanism exerted by tumor cells in response to endogenous antitumor activity. In 2015, the US Food and Drug Administration (FDA) approved two immuno-oncology agents, the PD-1 inhibitors nivolumab and pembrolizumab, for the treatment of previously treated advanced non-small cell lung cancer (NSCLC). Coincident with the clinical trials that led to these regulatory approvals has been the development of several immunohistochemistry (IHC) tests of PD-L1 expression, which may serve to select patients who will derive the most benefit from PD1- or PD-L1-directed therapy. The PD-L1 IHC assays are distinct in their methods and interpretation, which poses a challenge to clinicians selecting patients for these therapies. PMID:27090296

  7. 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.

  8. Anti-PD-1/PD-L1 antibody therapy for pretreated advanced nonsmall-cell lung cancer

    Science.gov (United States)

    Zhou, Guo-Wu; Xiong, Ye; Chen, Si; Xia, Fan; Li, Qiang; Hu, Jia

    2016-01-01

    Abstract Background: Anti-PD-1/PD-L1 antibody therapy is a promising clinical treatment for nonsmall-cell lung cancer (NSCLC). However, whether anti-PD-1/PD-L1 antibody therapy can provide added benefits for heavily pretreated patients with advanced NSCLC and whether the efficacy of anti-PD-1/PD-L1 antibody therapy relates to the tumor PD-L1 expression level remain controversial. Thus, this meta-analysis evaluated the efficacy and safety of anti-PD-1/PD-L1 antibody therapy for pretreated patients with advanced NSCLC. Methods: Randomized clinical trials were retrieved by searching the PubMed, EMBASE, ASCO meeting abstract, clinicaltrial.gov, and Cochrane library databases. The pooled hazard ratios (HRs) for overall survival (OS) and progression-free survival (PFS), and odds ratios for the overall response rate and adverse events (AEs) were calculated by STATA software. Results: Three randomized clinical trials involving 1141 pretreated patients with advanced NSCLC were included. These trials all compared the efficacy and safety of anti-PD-1/PD-L1 antibodies (nivolumab and MPDL3280A) with docetaxel. The results suggested that, for all patients, anti-PD-1/PD-L1 therapy could acquire a greater overall response (odds ratio = 1.50, 95% CI: 1.08–2.07, P = 0.015, P for heterogeneity [Ph] = 0.620) and longer OS (HR = 0.71, 95% CI: 0.61–0.81, P AEs of anti-PD-1/PD-L1 therapy were significantly lower than that of docetaxel. However, the risks of pneumonitis and hypothyroidism were significantly higher. Conclusion: Anti-PD-1/PD-L1 antibody therapy may significantly improve the outcomes for pretreated advanced NSCLC patients, with a better safety profile than docetaxel. PMID:27583876

  9. Association Analysis between the Polymorphisms of HSD11B1 and H6PD and Risk of Polycystic Ovary Syndrome in Chinese Population.

    Directory of Open Access Journals (Sweden)

    Rong Ju

    Full Text Available To evaluate whether single nucleotide polymorphisms of HSD11B1 (rs846908 and H6PD (rs6688832 and rs17368528 are associated with polycystic ovary syndrome (PCOS in Chinese population.A case-control study was implemented to investigate the association between HSD11B1 and H6PD polymorphisms and PCOS. Patients with PCOS (n = 335 and controls (n = 354 were recruited in this study. Genetic variants of HSD11B1 (rs846908 and H6PD (rs6688832 and rs17368528 were analyzed by TaqMan method.We found a significantly 0.79-fold lower risk of G allele of rs6688832 in control group compared with the patients with PCOS (adjusted OR, 0.79; 95%CI = 0.63-0.99; P = 0.040. Additionally, significant difference in the levels of follicle stimulating hormone (FSH was observed between AA and AG genotype in rs6688832. The rs6688832 AG genotype was associated with lower level of FSH (P = 0.039 and higher risk of hyperandrogenism (P = 0.016 in patients with PCOS. When all subjects were divided into different subgroups according to age and body mass index (BMI, we found that the frequency of G allele of rs6688832 was significantly higher in controls than that in PCOS patients in the subgroup of BMI > 23 (adjusted OR, 0.70; 95% CI = 0.50-0.98; P = 0.037.Our findings showed a statistical association between H6PD rs6688832 and PCOS risk in Chinese population. The G allele of rs6688832 in H6PD might exert potential genetic protective role against the development of PCOS, especially in overweight women. PCOS patients with AG genotype of rs6688832 might confer risk to the phenotype of hyperandrogenemia of PCOS.

  10. 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.

  11. 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).

  12. 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.

  13. 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.

  14. 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

    2016-01-01

    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 10(5). These findings open a pathway for extending visible-range SERS applications of novel 2D hybrid materials in sensors, catalysis, and biomedical applications. PMID:27557838

  15. 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.

  16. 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.

  17. PD-1/PD-L1 blockades in non-small-cell lung cancer therapy

    Directory of Open Access Journals (Sweden)

    Jing W

    2016-01-01

    Full Text Available Wang Jing,1,2,* Miaomiao Li,3,* Yan Zhang,2 Feifei Teng,2 Anqin Han,2 Li Kong,2 Hui Zhu2 1Weifang Medical University, Weifang, Shandong Province, People’s Republic of China; 2Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, Shandong Province, People’s Republic of China; 3Shandong Medical College, Jinan, Shandong Province, People’s Republic of China *Both these authors contributed equally to the work Abstract: Lung cancer is the leading cause of cancer death in males and the second leading cause of death in females worldwide. Non-small-cell lung cancer (NSCLC is the main pathological type of lung cancer, and most newly diagnosed NSCLC patients cannot undergo surgery because the disease is already locally advanced or metastatic. Despite chemoradiotherapy and targeted therapy improving clinical outcomes, overall survival remains poor. Immune checkpoint blockade, especially blockade of programmed death-1 (PD-1 receptor and its ligand PD-L1, achieved robust responses and improved survival for patients with locally advanced/metastatic NSCLC in preclinical and clinical studies. However, with regard to PD-1/PD-L1 checkpoint blockade as monotherapy or in combination with other antitumor therapies, such as chemotherapy, radiotherapy (including conventional irradiation and stereotactic body radiotherapy, and target therapy, there are still many unknowns in treating patients with NSCLC. Despite this limited understanding, checkpoint blockade as a novel therapeutic approach may change the treatment paradigm of NSCLC in the future. Here we review the main results from completed and ongoing studies to investigate the feasibility of PD-1/PD-L1 inhibitors, as monotherapy or combinatorial agents in patients with locally advanced and metastatic NSCLC, and explore optimal strategy in such patients. Keywords: immunotherapy, checkpoint, PD-1, PD-L1, NSCLC

  18. 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.

  19. In situ encapsulation of Pd inside the MCM-41 channel.

    Science.gov (United States)

    Lin, Xi-Jie; Zhong, Ai-Zhi; Sun, Yong-Bin; Zhang, Xing; Song, Wei-Guo; Lu, Rong-Wen; Cao, An-Min; Wan, Li-Jun

    2015-05-01

    Pd nanoparticles were successfully introduced into the channels of mesoporous silica MCM-41 with their dispersion well-tuned. We identified the dual role played by CTAB, which was critical for both the micelle template and Pd grafting, leading to the formation of a highly active Pd-MCM-41 nanocomposite for catalysing the Suzuki reaction. PMID:25827909

  20. 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.

  1. NMR investigation of Ag nanoparticles

    Science.gov (United States)

    Son, Kwanghyo; Jang, Zeehoon

    2013-01-01

    109Ag nuclear magnetic resonance (NMR) and relaxation measurements have been performed on two powder samples of Ag nanoparticles with average sizes of 20 nm and 80 nm. The measurements have been done in an external field of 9.4 T and in the temperature range 10 K Knight shift ( K) and the nuclear spin-lattice relaxation rate (1/ T 1) are observed to be almost identical to the values reported for the bulk Ag metal, whereby the Korringa ratio R(= K 2 T 1 T/S) is found to be 2.0 for both samples in the investigated temperature range.

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

    Lifescience Database Archive (English)

    Full Text Available His.Dig.50.AllAg.AGS hg19 Histone Digestive tract AGS SRX482979,SRX482980,SRX482982...,SRX482978,SRX482983,SRX482985,SRX482981,SRX482984 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Dig.50.AllAg.AGS.bed ...

  3. File list: Oth.Dig.20.AllAg.AGS [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.20.AllAg.AGS hg19 TFs and others Digestive tract AGS SRX367641,SRX371981,SR...X367642,SRX367640 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Dig.20.AllAg.AGS.bed ...

  4. File list: Oth.Dig.10.AllAg.AGS [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.10.AllAg.AGS hg19 TFs and others Digestive tract AGS SRX367641,SRX367642,SR...X371981,SRX367640 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Dig.10.AllAg.AGS.bed ...

  5. File list: ALL.Dig.05.AllAg.AGS [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Dig.05.AllAg.AGS hg19 All antigens Digestive tract AGS SRX367641,SRX367642,SRX3...X482983 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Dig.05.AllAg.AGS.bed ...

  6. File list: His.Dig.05.AllAg.AGS [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  7. File list: ALL.Dig.10.AllAg.AGS [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  8. File list: His.Dig.20.AllAg.AGS [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Dig.20.AllAg.AGS hg19 Histone Digestive tract AGS SRX482980,SRX482979,SRX482981...,SRX482978,SRX482982,SRX482983,SRX482985,SRX482984 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Dig.20.AllAg.AGS.bed ...

  9. File list: Oth.Dig.05.AllAg.AGS [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.05.AllAg.AGS hg19 TFs and others Digestive tract AGS SRX367641,SRX367642,SR...X371981,SRX367640 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Dig.05.AllAg.AGS.bed ...

  10. File list: Oth.Dig.50.AllAg.AGS [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.50.AllAg.AGS hg19 TFs and others Digestive tract AGS SRX367641,SRX371981,SR...X367642,SRX367640 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Dig.50.AllAg.AGS.bed ...

  11. File list: ALL.Dig.50.AllAg.AGS [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Dig.50.AllAg.AGS hg19 All antigens Digestive tract AGS SRX367641,SRX371982,SRX3...X367640 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Dig.50.AllAg.AGS.bed ...

  12. File list: ALL.Dig.20.AllAg.AGS [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Dig.20.AllAg.AGS hg19 All antigens Digestive tract AGS SRX367641,SRX371982,SRX3...X367640 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Dig.20.AllAg.AGS.bed ...

  13. File list: His.Dig.10.AllAg.AGS [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  14. 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.

  15. 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.

  16. Tridentate assembling ligands based on oxazoline and phosphorus donors in dinuclear Pd(I)-Pd(I) complexes.

    Science.gov (United States)

    Zhang, Jing; Pattacini, Roberto; Braunstein, Pierre

    2009-12-21

    To examine the bonding preferences of potentially tridentate phosphorus, nitrogen donor ligands on a dinuclear metal core, we have studied the coordination of the oxazoline-based ligands bis(4,5-dihydro-2-oxazolylmethyl)phenylphosphine (NPN) and bis(4,4-dimethyl-2-oxazolyl dimethylmethoxy)phenylphosphine (NOPON(Me2)) toward the dinuclear d(9)-d(9) Pd(I) complex [Pd(2)(NCMe)(6)][BF(4)](2). In the dinuclear product [Pd(2)(NPN-N,P,N)(2)](BF(4))(2) (1), in which the Pd-Pd bond length of 2.5489(7) A is rather short, the two interacting metal centers are P,N bridged by two molecules of the NPN ligand, forming two six-membered rings. The other oxazoline ring of each ligand further chelates a Pd center through its nitrogen atom, forming five-membered chelates, as in the mononuclear complex [PdCl(2)(NPN-N,P)] (5). In contrast, the reaction between [Pd(2)(NCMe)(6)](BF(4))(2) and NOPON(Me2) in the presence of LiCl afforded the mononuclear cationic complex [Pd(NOPON(Me2)-N,P,N)Cl](BF(4)) (3), which is also obtained by halide abstraction from [Pd(NOPON(Me2)-N,P)Cl(2)] with NaBF(4). When this reaction was performed in the presence of 1 equiv of t-BuNC, the new dinuclear Pd(I)-Pd(I) complex [Pd(2)Cl(2)(CNt-Bu)(NOPON(Me2)-N,P,N)] (4) was isolated, which can also be obtained from a comproportionation reaction between Pd(II) and Pd(0) complexes. The oxazoline in the P,N bridge is involved in a seven-membered ring moiety, a situation rarely encountered in Pd(I)-Pd(I) chemistry. Its nitrogen atom is coordinated trans to the isonitrile ligand whereas that of the P,N chelate at Pd(1) is trans to Pd(2). The fluxional processes involving the oxazoline moieties of the NPN and NOPON(Me2) ligands in 1 and 4, respectively, were examined by variable-temperature NMR spectroscopy. The crystal structures of 1, 3.0.5CH(3)CN, and 4 have been determined by X-ray diffraction. Prior to this work, relatively few complexes have been reported in the literature in which a potentially tridentate functional

  17. PD-1 Restrains Radiotherapy-Induced Abscopal Effect

    OpenAIRE

    Park, Sean S.; Dong, Haidong; Liu, Xin; Harrington, Susan M.; Krco, Christopher J.; Grams, Michael P.; Aaron S. Mansfield; Furutani, Keith M.; Olivier, Kenneth R; Kwon, Eugene D

    2015-01-01

    We investigated the influence of PD-1 expression on the systemic antitumor response (abscopal effect) induced by stereotactic ablative radiotherapy (SABR) in preclinical melanoma and renal cell carcinoma models. We compared the SABR-induced antitumor response in PD-1-expressing wild-type (WT) and PD-1-deficient knockout (KO) mice, and found that PD-1 expression compromises the survival of tumor-bearing mice treated with SABR. None of the PD-1 WT mice survived beyond 25 days, whereas 20% of th...

  18. Spin dynamics simulations at AGS

    Energy Technology Data Exchange (ETDEWEB)

    Huang, H.; MacKay, W.W.; Meot, F.; Roser, T.

    2010-05-23

    To preserve proton polarization through acceleration, it is important to have a correct model of the process. It has been known that with the insertion of the two helical partial Siberian snakes in the Alternating Gradient Synchrotron (AGS), the MAD model of AGS can not deal with a field map with offset orbit. The stepwise ray-tracing code Zgoubi provides a tool to represent the real electromagnetic fields in the modeling of the optics and spin dynamics for the AGS. Numerical experiments of resonance crossing, including spin dynamics in presence of the snakes and Q-jump, have been performed in AGS lattice models, using Zgoubi. This contribution reports on various results so obtained.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 102Pd(n, γ) Cross Section Measurement Using DANCE

    International Nuclear Information System (INIS)

    The neutron capture cross section of the proton rich nucleus 102Pd was measured with the Detector for Advanced Neutron Capture Experiments (DANCE) at the Los Alamos Neutron Science Center. The target was a 2 mg Pd foil with 78% enriched 102Pd. It was held by a 0.9 μm thick Mylar bag which was selected after comparing different thicknesses of Kapton and Mylar for their scattering background. To identify the contribution of the other Pd isotopes the data of a natural Pd sample was compared to the data of the 102Pd enriched sample. A 12C sample was used to determine the scattering background. The 102Pd(n, γ) rate is of importance for the p-process nucleosynthesis

  4. A first search of excited states double beta and double electron capture decays of Pd110 and Pd102

    CERN Document Server

    Lehnert, Bjoern

    2011-01-01

    A search for double beta decays of the palladium isotopes Pd110 and Pd102 into excited states of their daughters was performed. New half-life limits for the 2nubb and 0nubb decays into first excited 0+ and 2+ states of 2.54e19 yr and 2.14e19 yr (95% CL) for the Pd110 decay were obtained improving limits by two orders of magnitude. The corresponding half-lives for double electron capture transition of Pd102 are 1.73e18 yr and 2.54e18 yr (95% CL) respectively. These are the first measurements for Pd102.

  5. 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.

  6. Strong magnetization damping induced by Ag nanostructures in Ag/NiFe/Ag trilayers

    Science.gov (United States)

    Ley Domínguez, D.; da Silva, G. L.; Rodríguez-Suárez, R. L.; Rezende, S. M.; Azevedo, A.

    2013-07-01

    Ferromagnetic resonance has been used to investigate the magnetization relaxation in trilayers of Ag(t)/NiFe(10 nm)/Ag(t), sputter deposited on Si(001) where the thickness of the Ag layer varied from 0 nm to 24 nm. In the first stages of formation, the Ag layers form islands that work as mold to imprint defects or inhomogeneities on the NiFe film surface. The magnetic inhomogeneities and defects imprinted on the surface of the NiFe film act as extrinsic sources of magnetization relaxation in addition to the intrinsic Gilbert damping mechanism. Weak inhomogeneities are associated to the two-magnon scattering source and the strong inhomogeneities are associated to the fluctuations of the local magnetization. By adding the three different sources of magnetization damping, we were able to explain the azimuthal dependence of the ferromagnetic resonance linewidth.

  7. 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.

  8. 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.

  9. Photoreduction of Ag{sup +} in Ag/Ag{sub 2}S/Au memristor

    Energy Technology Data Exchange (ETDEWEB)

    Mou, N.I.; Tabib-Azar, M., E-mail: azar.m@utah.edu

    2015-06-15

    Highlights: • The effect of illumination on the operating voltages and switching speed of Ag/Ag{sub 2}S/Au memristors is studied • Illumination decreased the average switching time from high to low resistance states by ∼19% and decreased the turn-off voltages dramatically from −0.8 V to −0.25 V. • Photo-induced reduction of silver in Ag{sub 2}S may be used in three dimensional optical memories that can be electronically read and reset. • Illumination changed sulfur's valency and modified its oxidation/reduction potential. - Abstract: Silver halides and chalcogenides are excellent memristor materials that have been extensively used in the past as photosensitive layers in photography. Here we examine the effect of illumination on the operating voltages and switching speed of Ag/Ag{sub 2}S/Au memristors using a green laser (473–523 nm). Our results indicate that illumination decreases the average switching time from high to low resistance states by ∼19% and decreases the turn-off voltages dramatically from −0.8 V to −0.25 V that we attribute to the change in sulfur valency and a photo-induced change in its oxidation/reduction potential. Photo-induced reduction of silver in Ag{sub 2}S may be used in three dimensional optical memories that can be electronically read and reset.

  10. 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.

  11. 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.)

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.)

  17. 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.

  18. Atomistic modeling of ternary additions to NiTi and quaternary additions to Ni-Ti-Pd, Ni-Ti-Pt and Ni-Ti-Hf shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mosca, H.O., E-mail: hmosca@cnea.gov.ar [Gcia. Investigacion y Aplicaciones, CNEA, Av. Gral Paz 1499, B1650KNA San Martin (Argentina); GCMM, UTN, FRG Pacheco, Av. H. Yrigoyen 288, Gral. Pacheco (Argentina); Bozzolo, G. [Loyola University Maryland, 4501 N. Charles St., Baltimore, MD 21210 (United States); Grosso, M.F. del [Gcia. Investigacion y Aplicaciones, CNEA, Av. Gral Paz 1499, B1650KNA San Martin (Argentina); GCMM, UTN, FRG Pacheco, Av. H. Yrigoyen 288, Gral. Pacheco (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, CONICET (Argentina)

    2012-08-15

    The behavior of ternary and quaternary additions to NiTi shape memory alloys is investigated using a quantum approximate method for the energetics. Ternary additions X to NiTi and quaternary additions to Ni-Ti-Pd, Ni-Ti-Pt, and Ni-Ti-Hf alloys, for X=Au, Pt, Ir, Os, Re, W, Ta,Ag, Pd, Rh, Ru, Tc, Mo, Nb, Zr, Zn, Cu, Co, Fe, Mn, V, Sc, Si, Al and Mg are considered. Bulk properties such as lattice parameter, energy of formation, and bulk modulus of the B2 alloys are studied for variations due to the presence of one or two simultaneous additives.

  19. 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.

  20. 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.

  1. Wavelet Analysis for Classification of Multi-source PD Patterns

    OpenAIRE

    Lalitha, EM; Satish, L.

    2000-01-01

    Multi-resolution signal decomposition (MSD) technique of wavelet transforms has interesting properties of capturing the embedded horizontal, vertical and diagonal variations within an image in a separable farm. This feature was exploited to identify individual partial discharge (PD) sources present in multi-source PD Patterns, usually encountered during practical PD measurements, Employing the Daubechies wavelet, features were extracted from the third level decomposed and reconstructed horizo...

  2. PD-1 marks dysfunctional regulatory T cells in malignant gliomas

    OpenAIRE

    Lowther, Daniel E.; Goods, Brittany A.; Lucca, Liliana E.; Lerner, Benjamin A.; Raddassi, Khadir; van Dijk, David; Hernandez, Amanda L.; Duan, Xiangguo; Gunel, Murat; Coric, Vlad; Krishnaswamy, Smita; Love, J. Christopher; Hafler, David A.

    2016-01-01

    Immunotherapies targeting the immune checkpoint receptor programmed cell death protein 1 (PD-1) have shown remarkable efficacy in treating cancer. CD4+CD25hiFoxP3+ Tregs are critical regulators of immune responses in autoimmunity and malignancies, but the functional status of human Tregs expressing PD-1 remains unclear. We examined functional and molecular features of PD-1hi Tregs in healthy subjects and patients with glioblastoma multiforme (GBM), combining functional assays, RNA sequencing,...

  3. Nickel-like spectra of elements Y XII to Ag XX from a vacuum spark

    International Nuclear Information System (INIS)

    The spectra of elements Y, Zr, Nb, Mo, Ru, Rh, Pd and Ag in the range 10-100 A were obtained from a high power vacuum spark and a grazing incidence high resolution spectrograph. The transitions 3d10-3d94p, -3d94f, 3d95p, -3d95f were identified. The agreement with ab initio relativistic calculations is very good. The relevance of jj coupling scheme for level labeling is discussed, as well as the importance of relativistic effects, by comparing with other results on high Z atoms (up to Pt)

  4. 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...

  5. 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.

  6. 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

  7. 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

  8. 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-

  9. A straightforward and effective strategy for controllable synthesis of Ag/Ag2S and Ag/CdS heterojunction nanowires

    International Nuclear Information System (INIS)

    Ag/Ag2S 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/Ag2S HJNWs. The sizes, positions, and spacing distances between the Ag2S or CdS NPs of the growing Ag2S and CdS NPs in the Ag/Ag2S 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 Ag2S and CdS NPs in the Ag/Ag2S and Ag/CdS HJNWs could be effectively controlled while PVP concentration could tailor the sizes and spacing distances between the Ag2S or CdS NPs of the growing Ag2S and CdS NPs in the Ag/Ag2S and Ag/CdS HJNWs. We also proposed a primary experimental model to illustrate the growth mechanism of the Ag/Ag2S and Ag/CdS HJNWs

  10. 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.

  11. `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.

  12. 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.

  13. 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......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...

  14. Ag-Ag2S Hybrid Nanoprisms: Structural versus Plasmonic Evolution.

    Science.gov (United States)

    Shahjamali, Mohammad M; Zhou, Yong; Zaraee, Negin; Xue, Can; Wu, Jinsong; Large, Nicolas; McGuirk, C Michael; Boey, Freddy; Dravid, Vinayak; Cui, Zhifeng; Schatz, George C; Mirkin, Chad A

    2016-05-24

    Recently, Ag-Ag2S hybrid nanostructures have attracted a great deal of attention due to their enhanced chemical and thermal stability, in addition to their morphology- and composition-dependent tunable local surface plasmon resonances. Although Ag-Ag2S nanostructures can be synthesized via sulfidation of as-prepared anisotropic Ag nanoparticles, this process is poorly understood, often leading to materials with anomalous compositions, sizes, and shapes and, consequently, optical properties. In this work, we use theory and experiment to investigate the structural and plasmonic evolution of Ag-Ag2S nanoprisms during the sulfidation of Ag precursors. The previously observed red-shifted extinction of the Ag-Ag2S hybrid nanoprism as sulfidation occurs contradicts theoretical predictions, indicating that the reaction does not just occur at the prism tips as previously speculated. Our experiments show that sulfidation can induce either blue or red shifts in the extinction of the dipole plasmon mode, depending on reaction conditions. By elucidating the correlation with the final structure and morphology of the synthesized Ag-Ag2S nanoprisms, we find that, depending on the reaction conditions, sulfidation occurs on the prism tips and/or the (111) surfaces, leading to a core(Ag)-anisotropic shell(Ag2S) prism nanostructure. Additionally, we demonstrate that the direction of the shift in the dipole plasmon is a function of the relative amounts of Ag2S at the prism tips and Ag2S shell thickness around the prism.

  15. Photoreduction of Ag+ in Ag/Ag2S/Au memristor

    Science.gov (United States)

    Mou, N. I.; Tabib-Azar, M.

    2015-06-01

    Silver halides and chalcogenides are excellent memristor materials that have been extensively used in the past as photosensitive layers in photography. Here we examine the effect of illumination on the operating voltages and switching speed of Ag/Ag2S/Au memristors using a green laser (473-523 nm). Our results indicate that illumination decreases the average switching time from high to low resistance states by ∼19% and decreases the turn-off voltages dramatically from -0.8 V to -0.25 V that we attribute to the change in sulfur valency and a photo-induced change in its oxidation/reduction potential. Photo-induced reduction of silver in Ag2S may be used in three dimensional optical memories that can be electronically read and reset.

  16. 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.

  17. 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.

  18. 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

  19. 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.

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

    International Nuclear Information System (INIS)

    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)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

  1. An efficient photocatalyst for degradation of various organic dyes: Ag@Ag2MoO4-AgBr composite.

    Science.gov (United States)

    Bai, Yu-Yang; Lu, Yi; Liu, Jin-Ku

    2016-04-15

    The Ag2MoO4-AgBr composite was prepared by a facile in-situ anion-exchange method, then the Ag nanoparticles were coated on this composite through photodeposition route to form a novel Ag@Ag2MoO4-AgBr composite. The in-situ Br(-) replacement in a crystal lattice node position of Ag2MoO4 crystal allows for overcoming the resistance of electron transition effectively. Meanwhile silver nano-particles on the surface of Ag@Ag2MoO4-AgBr composite could act as electron traps to intensify the photogeneration electron-hole separation and the subsequent transfer of the trapped electron to the adsorbed O2 as an electron acceptor. As an efficient visible light catalyst, the Ag@Ag2MoO4-AgBr composite exhibited superior photocatalytic activity for the degradation of various organic dyes. The experimental results demonstrated superior photocatalytic rate of Ag@Ag2MoO4-AgBr composite compared to pure AgBr and Ag2MoO4 crystals (37.6% and 348.4% enhancement respectively). The Ag@Ag2MoO4-AgBr composite cloud degraded Rhodamin B, bromophenol blue, and amino black 10b completed in 7min. PMID:26775100

  2. AGS experiments---1987, 1988, 1989

    International Nuclear Information System (INIS)

    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

  3. 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.

  4. 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.

  5. 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.

  6. AGS 20th anniversary celebration

    International Nuclear Information System (INIS)

    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

  7. AGS experiments, 1988, 1989, 1990

    International Nuclear Information System (INIS)

    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

  8. AGS experiments: 1985, 1986, 1987

    International Nuclear Information System (INIS)

    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

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

    Directory of Open Access Journals (Sweden)

    Petr Suchomel

    Full Text Available 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.

  10. Antibacterial biodegradable Mg-Ag alloys

    OpenAIRE

    D Tie; F Feyerabend; W-D Müller; Schade, R; Liefeith, K; KU Kainer; Willumeit, R.

    2013-01-01

    The use of magnesium alloys as degradable metals for biomedical applications is a topic of ongoing research and the demand for multifunctional materials is increasing. Hence, binary Mg-Ag alloys were designed as implant materials to combine the favourable properties of magnesium with the well-known antibacterial property of silver. In this study, three Mg-Ag alloys, Mg2Ag, Mg4Ag and Mg6Ag that contain 1.87 %, 3.82 % and 6.00 % silver by weight, respectively, were cast and processed with solut...

  11. Antibacterial Mg-Ag biodegradable alloys

    OpenAIRE

    Tie, Di

    2013-01-01

    The use of magnesium alloys as degradable metals for biomedical applications is topic of ongoing research. As a further aspect, the demand for multifunctional materials is increasing. Hence, binary Mg-Ag alloys were designed to combine the favourable properties of magnesium with the wellknown antibacterial property of silver. In this study, three Mg-Ag alloys, Mg2Ag, Mg4Ag and Mg6Ag which contain 1.87%, 3.82% and 6.00% silver by weight respectively were casted and processed with solution and ...

  12. Structure characterization of Pd/Co/Pd tri-layer films epitaxially grown on MgO single-crystal substrates

    Energy Technology Data Exchange (ETDEWEB)

    Tobari, Kousuke, E-mail: tobari@futamoto.elect.chuo-u.ac.jp; Ohtake, Mitsuru; Nagano, Katsumasa; Futamoto, Masaaki

    2011-09-30

    Pd/Co/Pd tri-layer films were prepared on MgO substrates of (001), (111), and (011) orientations at room temperature by ultra high vacuum rf magnetron sputtering. The detailed film structures around the Co/Pd and the Pd/Co interfaces are investigated by reflection high energy electron diffraction. Pd layers of (001){sub fcc}, (111){sub fcc}, and (011){sub fcc} orientations epitaxially grow on the respective MgO substrates. Strained fcc-Co(001) single-crystal layers are formed on the Pd(001){sub fcc} layers by accommodating the fairly large lattice mismatch between the Co and the Pd layers. On the Co layers,, Pd polycrystalline layers are formed. When Co films are formed on the Pd(111){sub fcc} and the Pd(011){sub fcc} layers, atomic mixing is observed around the Co/Pd interfaces and fcc-CoPd alloy phases are coexisting with Co crystals. The Co crystals formed on the Pd(111){sub fcc} layers consist of hcp(0001) + fcc(111) and Pd(111){sub fcc} epitaxial layers are formed on the Co layers. Co crystals epitaxially grow on the Pd(011){sub fcc} layers with two variants, hcp(11-bar 00) and fcc(111). On the Co layers, Pd(011){sub fcc} epitaxial layers are formed.

  13. 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...

  14. Expression of PD-L1 on canine tumor cells and enhancement of IFN-γ production from tumor-infiltrating cells by PD-L1 blockade.

    Directory of Open Access Journals (Sweden)

    Naoya Maekawa

    Full Text Available Programmed death 1 (PD-1, an immunoinhibitory receptor, and programmed death ligand 1 (PD-L1, its ligand, together induce the "exhausted" status in antigen-specific lymphocytes and are thus involved in the immune evasion of tumor cells. In this study, canine PD-1 and PD-L1 were molecularly characterized, and their potential as therapeutic targets for canine tumors was discussed. The canine PD-1 and PD-L1 genes were conserved among canine breeds. Based on the sequence information obtained, the recombinant canine PD-1 and PD-L1 proteins were constructed; they were confirmed to bind each other. Antibovine PD-L1 monoclonal antibody effectively blocked the binding of recombinant PD-1 with PD-L1-expressing cells in a dose-dependent manner. Canine melanoma, mastocytoma, renal cell carcinoma, and other types of tumors examined expressed PD-L1, whereas some did not. Interestingly, anti-PD-L1 antibody treatment enhanced IFN-γ production from tumor-infiltrating cells. These results showed that the canine PD-1/PD-L1 pathway is also associated with T-cell exhaustion in canine tumors and that its blockade with antibody could be a new therapeutic strategy for canine tumors. Further investigations are needed to confirm the ability of anti-PD-L1 antibody to reactivate canine antitumor immunity in vivo, and its therapeutic potential has to be further discussed.

  15. 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

  16. 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.

  17. 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.

  18. 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...

  19. 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.

  20. 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)

  1. [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.

  2. Effects of Ag nanoshape and AgGa phase in Ag-Si nanostructure using 2-step etching process

    International Nuclear Information System (INIS)

    Research highlights: → In order to connect biotechnology and semiconductor fabrication, the two step DWE (dry-wet etching, DWE) of Si nanohollow structure needs a development. Because the DWE is a new material process, its mechanism has still not been examined, and in particular the redox reaction and the effect of sidewalls. The present nanostructures and results have been obtained by an advanced method, and 15-30 nm Ag nano-particles were able to enhance the DWE mechanism in the Ag/Si nanostructures. - Abstract: The etching scale was controled by the layball process and a focus ion beam (FIB) was used to investige the dry-wet etching (DWE) mechanism. Increasing the beam current of dry-etching raised the height of nano prominent structures, but deteriorated the interface of Ag/Si film, and even damaged the Ag film because of Ga+ bombardment. Regardless of the Ag nanoshape deposition, the residual Ag films were doped with Ga+ and were sensitive to DWE. After wet-etching, the nano hollow formed and the Ag films sunk. However, AgGa sidewall films formed by the concentration gradient and the oxidative potential and this increased the volume of microporous phases, resulting in a reduction in the depth. Also, 15-30 nm Ag nano-particles were able to enhance the DWE mechanism in the Ag/Si nanostructures.

  3. 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)

  4. Synthesis of bimetallic Pt-Pd core-shell nanocrystals and their high electrocatalytic activity modulated by Pd shell thickness

    Science.gov (United States)

    Li, Yujing; Wang, Zhi Wei; Chiu, Chin-Yi; Ruan, Lingyan; Yang, Wenbing; Yang, Yang; Palmer, Richard E.; Huang, Yu

    2012-01-01

    Bimetallic Pt-Pd core-shell nanocrystals (NCs) are synthesized through a two-step process with controlled Pd thickness from sub-monolayer to multiple atomic layers. The oxygen reduction reaction (ORR) catalytic activity and methanol oxidation reactivity of the core-shell NCs for fuel cell applications in alkaline solution are systematically studied and compared based on different Pd thickness. It is found that the Pd shell helps to reduce the over-potential of ORR by up to 50mV when compared to commercial Pd black, while generating up to 3-fold higher kinetic current density. The carbon monoxide poisoning test shows that the bimetallic NCs are more resistant to the CO poisoning than Pt NCs and Pt black. It is also demonstrated that the bimetallic Pt-Pd core-shell NCs can enhance the current density of the methanol oxidation reaction, lowering the over-potential by 35 mV with respect to the Pt core NCs. Further investigation reveals that the Pd/Pt ratio of 1/3, which corresponds to nearly monolayer Pd deposition on Pt core NCs, gives the highest oxidation current density and lowest over-potential. This study shows for the first time the systematic investigation of effects of Pd atomic shells on Pt-Pd bimetallic nanocatalysts, providing valuable guidelines for designing high-performance catalysts for fuel cell applications.Bimetallic Pt-Pd core-shell nanocrystals (NCs) are synthesized through a two-step process with controlled Pd thickness from sub-monolayer to multiple atomic layers. The oxygen reduction reaction (ORR) catalytic activity and methanol oxidation reactivity of the core-shell NCs for fuel cell applications in alkaline solution are systematically studied and compared based on different Pd thickness. It is found that the Pd shell helps to reduce the over-potential of ORR by up to 50mV when compared to commercial Pd black, while generating up to 3-fold higher kinetic current density. The carbon monoxide poisoning test shows that the bimetallic NCs are more

  5. Beta decay of 97Ag: evidence for the Gamow-Teller resonance near 100Sn

    International Nuclear Information System (INIS)

    In two complementary measurements, a cube like array of 6 Euroball-Cluster germanium detectors and a total-absorption γ-spectrometer were used to investigate the β decay of 97Ag, a three proton-hole nucleus with respect to the 100Sn core. The half-life and QEC value of the decay of the 9/2+ ground-state of 97Ag were determined to be 25.9(4) s and 6.98(11) MeV respectively. A total of 603 γ rays (578 new) was observed, and 151 levels (132 new) in 97Pd have been identified. An interesting β-delayed γ cascade was observed, which comprises 6 γ-transitions with a de-excitation pattern involving an initial increase of the level spin. The Gamow-Teller (GT) β-decay strength distributions from the two measurements reveal a large GT resonance around 4 MeV with a width of about 1.8 MeV. The hindrance factor for the total GT strength summed from the ground-state up to 6 MeV excitation energy in 97Pd, amounts to 4.3(6) with reference to a shell-model prediction. This factor is discussed in comparison with a core-polarization and a Monte-Carlo shell-model calculation. (orig.)

  6. 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)

  7. Gold and palladium minerals (including empirical PdCuBiSe3) from the former Roter Bär mine, St. Andreasberg, Harz Mountains, Germany: a result of low-temperature, oxidising fluid overprint

    Science.gov (United States)

    Cabral, Alexandre Raphael; Ließmann, Wilfried; Lehmann, Bernd

    2015-10-01

    At Roter Bär, a former underground mine in the polymetallic deposits of St. Andreasberg in the middle-Harz vein district, Germany, native gold and palladium minerals occur very locally in clausthalite-hematite pockets of few millimetres across in carbonate veinlets. The native gold is a Au-Ag intermetallic compound and the palladium minerals are characterised as mertieite-II [Pd8(Sb,As)3] and empirical PdCuBiSe3 with some S. The latter coexists with bohdanowiczite (AgBiSe2), a mineral that is stable below 120 °C. The geological setting of Roter Bär, underneath a post-Variscan unconformity, and its hematite-selenide-gold association suggest that oxidising hydrothermal brines of low temperature were instrumental to the Au-Pd mineralisation. The Roter Bär Au-Pd mineralisation can be explained by Permo-Triassic, red-bed-derived brines in the context of post-Variscan, unconformity-related fluid overprint.

  8. 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.

  9. 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.

  10. Deteksi HBsAg dan HBeAg dalam Saliva Pengidap Virus Hepatitis B

    Directory of Open Access Journals (Sweden)

    Riemawati A. Lesmana

    2015-10-01

    Full Text Available Transmission of hepatitis B virus (HBV via blood or its product has been well established. However, body fluids like urine and saliva may also contain HBV. A complete HBV consists of HBsAg, HBeAg, HBcAg dan partikel DNA. Hepatitis B carrier is detected by the presence of serologic marker HBsAg while the ongoing viral replication or infectivity is diagnosed by the presence of HBeAg or DNA particle. Meanwhile dentists will often contact with the saliva of their patients in daily practice. This cross-sectional study was carried out to assess the infectivity of the saliva of HBV carriers. During a 10 month period (August 1994 - May 1995 detection of HBsAg and HBeAg in blood and saliva were done in 97 HBV carriers using the ELISA method (Enzyme Linked Immunosorbent Assay. Of 97 HBV carriers both positive gor HBsAG in blood were found 56 (Group I and positive HBsAg and negativa HBeAg in the other 41 (Group II. Examination of the saliva of HBV carriers in Group I showed positive HBsAg as well as HBeAg in 48 (85,7%, only positive for HBsAg in 5 (10,7% and both negative for HBsAg and HBeAg in the other 2 (3,6% where as in Group II positive for both HBsAg and HBeAG in the remaining 10 (24,4%. In conclusion, the majority of highly infectious hepatitis B carriers do also have infectious saliva which could be an important source of infection and transmission of the virus in the field of dentistry.

  11. 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. PMID:24928455

  12. 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.

  13. Ag/AgBr/TiO2 visible light photocatalyst for destruction of azodyes and bacteria.

    Science.gov (United States)

    Hu, Chun; Lan, Yongqing; Qu, Jiuhui; Hu, Xuexiang; Wang, Aimin

    2006-03-01

    Ag/AgBr/TiO2 was prepared by the deposition-precipitation method and was found to be a novel visible light driven photocatalyst. The catalyst showed high efficiency for the degradation of nonbiodegradable azodyes and the killing of Escherichia coli under visible light irradiation (lambda>420 nm). The catalyst activity was maintained effectively after successive cyclic experiments under UV or visible light irradiation without the destruction of AgBr. On the basis of the characterization of X-ray diffraction, X-ray photoelectron spectroscopy, and Auger electron spectroscopy, the surface Ag species mainly exist as Ag0 in the structure of all samples before and after reaction, and Ag0 species scavenged hVB+ and then trapped eCB- in the process of photocatalytic reaction, inhibiting the decomposition of AgBr. The studies of ESR and H2O2 formation revealed that *OH and O2*- were formed in visible light irradiated aqueous Ag/AgBr/TiO2 suspension, while there was no reactive oxygen species in the visible light irradiated Ag0/TiO2 system. The results indicate that AgBr is the main photoactive species for the destruction of azodyes and bacteria under visible light. In addition, the bactericidal efficiency and killing mechanism of Ag/AgBr/TiO2 under visible light irradiation are illustrated and discussed. PMID:16509698

  14. 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.

  15. Effect of Pd ions in the chemical etching solution

    Institute of Scientific and Technical Information of China (English)

    Guixiang Wang; Ning Li; Deyu Li

    2007-01-01

    The acrylonitrile-butadiene-styrene (ABS) surface was etched by dipping it into chromic acid-sulfuric acid containing a trace amount of palladium. The surface roughness, activity, and valence bond were characterized by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The results showed that with the increase of Pd concentration in the etching solution the ABS surface roughness reduced. The ratio of O to C increases and forms a large amount of O=C-O functional groups by dipping into Pd contained etching solution, thus the amount of colloids palladium adsorption increases. The carboxyl group acts as the adsorption site for the Pd/Sn catalyst.

  16. 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.

  17. Cloth catalysts in water denitrification: I. Pd on glass fibers

    OpenAIRE

    Matatov-Meytal, Y.; Barelko, V.; Yuranov, I.; Sheintuch, M.

    2000-01-01

    Fiber catalysts are easy to handle and free of mass-transfer resistance. This report is the first application of cloth catalysts to water denitrification. In this work, cloths woven from glass fibers (GF) of 7–10 mm in diameter, impregnated with Pd, were tested in a semi-batch reactor to evaluate their effectiveness in the catalytic liquid phase hydrogenation of nitrites and nitrates. The catalytic properties of Pd-GF cloths were evaluated as a function of Pd loading as well of chemical comp...

  18. 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.

  19. Observation of a Ag protrusion on a Ag2S island using a scanning tunneling microscope

    OpenAIRE

    Takeo Ohno; Tsuyoshi Hasegawa

    2015-01-01

    A silver sulfide (Ag2S) island as an ionic conductor in resistive switching memories was formed and a protrusion of silver from the Ag2S formed by an electrochemical reaction was observed using a scanning tunneling microscope.

  20. CD274/PD-L1 gene amplification and PD-L1 protein expression are common events in squamous cell carcinoma of the oral cavity

    Science.gov (United States)

    Straub, Melanie; Drecoll, Enken; Pfarr, Nicole; Weichert, Wilko; Langer, Rupert; Hapfelmeier, Alexander; Götz, Carolin; Wolff, Klaus-Dietrich; Kolk, Andreas; Specht, Katja

    2016-01-01

    Immunomodulatory therapies, targeting the immune checkpoint receptor-ligand complex PD-1/PD-L1 have shown promising results in early phase clinical trials in solid malignancies, including carcinomas of the head and neck. In this context, PD-L1 protein expression has been proposed as a potentially valuable predictive marker. In the present study, expression of PD-L1 and PD-1 was evaluated by immunohistochemistry in 80 patients with predominantly HPV-negative oral squamous cell carcinomas and associated nodal metastasis. In addition, CD274/PD-L1 gene copy number status was assessed by fluorescence in situ hybridization analysis. PD-L1 expression was detected in 36/80 (45%) cases and concordance of PD-L1 expression in primary tumor and corresponding nodal metastasis was present in only 20/28 (72%) cases. PD-1 expression was found in tumor-infiltrating lymphocytes (TILs) but not in tumor cells. CD274/PD-L1 gene amplification was detected in 19% of cases, with high level PD-L1 amplification present in 12/80 (15%), and low level amplification in 3/80 (4%). Interestingly, CD274/PD-L1 gene amplification was associated with positive PD-L1 immunostaining in only 73% of cases. PD-L1 copy number status was concordant in primary tumor and associated metastases. Clinically, PD-L1 tumor immunopositivity was associated with a higher risk for nodal metastasis at diagnosis, overall tumor related death und recurrence. Based on our findings we propose to include PD-L1 copy number status in addition to protein status in screening programs for future clinical trials with immunotherapeutic strategies targeting the PD-1/PD-L1 axis. PMID:26918453

  1. CD274/PD-L1 gene amplification and PD-L1 protein expression are common events in squamous cell carcinoma of the oral cavity.

    Science.gov (United States)

    Straub, Melanie; Drecoll, Enken; Pfarr, Nicole; Weichert, Wilko; Langer, Rupert; Hapfelmeier, Alexander; Götz, Carolin; Wolff, Klaus-Dietrich; Kolk, Andreas; Specht, Katja

    2016-03-15

    Immunomodulatory therapies, targeting the immune checkpoint receptor-ligand complex PD-1/PD-L1 have shown promising results in early phase clinical trials in solid malignancies, including carcinomas of the head and neck. In this context, PD-L1 protein expression has been proposed as a potentially valuable predictive marker. In the present study, expression of PD-L1 and PD-1 was evaluated by immunohistochemistry in 80 patients with predominantly HPV-negative oral squamous cell carcinomas and associated nodal metastasis. In addition, CD274/PD-L1 gene copy number status was assessed by fluorescence in situ hybridization analysis. PD-L1 expression was detected in 36/80 (45%) cases and concordance of PD-L1 expression in primary tumor and corresponding nodal metastasis was present in only 20/28 (72%) cases. PD-1 expression was found in tumor-infiltrating lymphocytes (TILs) but not in tumor cells. CD274/PD-L1 gene amplification was detected in 19% of cases, with high level PD-L1 amplification present in 12/80 (15%), and low level amplification in 3/80 (4%). Interestingly, CD274/PD-L1 gene amplification was associated with positive PD-L1 immunostaining in only 73% of cases. PD-L1 copy number status was concordant in primary tumor and associated metastases. Clinically, PD-L1 tumor immunopositivity was associated with a higher risk for nodal metastasis at diagnosis, overall tumor related death und recurrence. Based on our findings we propose to include PD-L1 copy number status in addition to protein status in screening programs for future clinical trials with immunotherapeutic strategies targeting the PD-1/PD-L1 axis. PMID:26918453

  2. Ag/AgCl电极自噪声的测定%Measurement of Ag/AgCl electrode's self-noise

    Institute of Scientific and Technical Information of China (English)

    胡鹏; 谭浩; 龚沈光

    2011-01-01

    In order to validate whether the Ag/AgCl electrode can be used to detect weak ocean electric signals, a measurement experiment of Ag/AgCl electrode's self-noise was designed based on the analysis of the reason for Ag/AgCl electrode's self-noise. A pair of Ag/AgCl electrode's self-noises in different seawater conductivities was measured in the laboratory. The results show that the electrode can be used to measure the ship's near electric field and its self-noise variation with seawater conductivity. In addition, when the seawater conductivity increases to a certain value, the fluctuation of the electrode's self-noise is small or approximately considered to be zero. The conclusion drawn is significant for the design of an underwater electric field sensor with low self-noise and the analysis of the measured data of the underwater electric field.%为了验证固态Ag/AgCl电极能否满足对微弱海洋电场信号的探测,在对Ag/AgCl电极自噪声产生机理分析的基础上,设计了Ag/AgCl电极自噪声的测量实验.通过实验,测量了不同海水电导率下一对Ag/AgCl电极的自噪声.测量结果表明:该电极能满足船舶电场的近场测量,且其自噪声随海水电导率的增大而减小,当海水电导率增大到一定程度时,该电极的自噪声变化起伏很小,可近似认为没有变化.所得结论对低噪声水下电场传感器的研制和实测水下电场数据的分析具有一定的借鉴意义.

  3. 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.

  4. 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...

  5. Methanol oxidation on Pd/Pt(poly) in alkaline solution

    Science.gov (United States)

    Maksic, A.; Rakocevic, Z.; Smiljanic, M.; Nenadovic, M.; Strbac, S.

    2015-01-01

    Bimetallic electrodes prepared by Pd nanoislands spontaneously deposited on polycrystalline platinum, Pt(poly), at submonolayer coverage were explored for methanol oxidation in alkaline media. Characterization of obtained Pd/Pt(poly) nanostructures was performed ex situ by AFM imaging, spectroscopic ellipsometry and by X-ray photoelectron spectroscopy. In situ characterization of the obtained electrodes and subsequent methanol oxidation measurements were performed by cyclic voltammetry in 0.1 M KOH. Platinum surface with 35% Pd coverage exhibited the highest catalytic activity for methanol oxidation in alkaline media, exceeding those of bare Pt and Pd. Both synergistic and electronic effects are responsible for such enhanced catalysis. The origin of the synergistic effect and possible reaction pathways for methanol oxidation were discussed taking into account the activity of obtained bimetallic electrodes for the oxidation of CO and formaldehyde, as the most probable reaction intermediates.

  6. 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.

  7. Design of Pd-Based Bimetallic Catalysts for ORR: A DFT Calculation Study

    Directory of Open Access Journals (Sweden)

    Lihui Ou

    2015-01-01

    Full Text Available Developing Pd-lean catalysts for oxygen reduction reaction (ORR is the key for large-scale application of proton exchange membrane fuel cells (PEMFCs. In the present paper, we have proposed a multiple-descriptor strategy for designing efficient and durable ORR Pd-based alloy catalysts. We demonstrated that an ideal Pd-based bimetallic alloy catalyst for ORR should possess simultaneously negative alloy formation energy, negative surface segregation energy of Pd, and a lower oxygen binding ability than pure Pt. By performing detailed DFT calculations on the thermodynamics, surface chemistry and electronic properties of Pd-M alloys, Pd-V, Pd-Fe, Pd-Zn, Pd-Nb, and Pd-Ta, are identified theoretically to have stable Pd segregated surface and improved ORR activity. Factors affecting these properties are analyzed. The alloy formation energy of Pd with transition metals M can be mainly determined by their electron interaction. This may be the origin of the negative alloy formation energy for Pd-M alloys. The surface segregation energy of Pd is primarily determined by the surface energy and the atomic radius of M. The metals M which have smaller atomic radius and higher surface energy would tend to favor the surface segregation of Pd in corresponding Pd-M alloys.

  8. 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.

  9. Pd/Cr Strain Gauges For High Temperatures

    Science.gov (United States)

    Lei, Jih-Fen

    1992-01-01

    Temperature-compensated Pd/Cr electrical-resistance strain gauges measure static strains in combustors, blades, and vanes of gas turbine engines. Made of alloy of 87 weight percent Pd and 13 weight percent Cr. Microstructure highly stable; undergoes no transformation of phase between ambient temperature and 1,000 degrees C. Gives highly repeatable readings with low drift at temperatures from ambient to 600 degrees C.

  10. (LeanPD) Towards Lean Product and Process Development

    OpenAIRE

    Khan, Muhammad; Al-Ashaab, Ahmed; Shehab, Essam; Haque, Badr; Ewers, Paul; Sorli, Mikel; Sopelana, Amaia

    2011-01-01

    Abstract Successes in lean manufacturing have led researchers and practitioners to consider extending `lean? to different parts of the engineering enterprise, including product and process development (PPD). Lean product development has been understood to mean lean manufacturing applied to product development (PD), while the roots of lean PD ? just like lean manufacturing - go back to Toyota. This paper presents the methodology adopted in order to pave the way towards a coherent le...

  11. Incommensurate magnetic ordering of PrPdAl

    Energy Technology Data Exchange (ETDEWEB)

    Keller, L. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Doenni, A. [National Research Inst. for Metals, Tsukuba, Ibaraki (Japan). Tsukuba Lab.; Fauth, F. [Institut Max von Laue - Paul Langevin, 75 - Paris (France)

    1997-09-01

    The intermetallic rare earth compound PrPdAl with ZrNiAl-type structure was investigated by means of powder neutron diffraction. PrPdAl orders below T{sub N} {approx_equal}4.2 K with an incommensurate antiferromagnetic propagation vector k = [1/2,0,{tau}], {tau}=0.398. The best fit was obtained with a sinusoidal modulation of the magnetic moments along the c-axis. (author) 2 figs., 2 refs.

  12. THE RELATIONSHIP BETWEEN PERIODONTAL DISEASE (PD AND CARDIOVASCULAR DISEASE (CVD.

    Directory of Open Access Journals (Sweden)

    Maurizio Trevisan

    2010-10-01

    Full Text Available The recent focus on the potential link between periodontal and cardiovascular disease (PD and CVD  is part of the larger renewed interest on the role of infection and inflammation in the etiology of atherosclerosis and its clinical manifestations.  Periodontal Disease is an inflammatory process affecting the periodontium, the tissue that surrounds and supports the teeth . The process usually starts with an inflammatory process of the gum (gingivitis but it may progress with an extensive involvement of the gum, as well as the periodontal ligament and the bone surrounding the teeth resulting in substantial bone loss. Periodontal disease is a common oral pathological condition in the adult age and represents the leading cause of tooth loss. PD prevalence increases with age and there are estimates that up to 49,000,000 Americans may suffer from some form of gum disease. The gingival plaque associated with PD is colonized by a number of gram-positive and gram-negative bacteria that have been shown to affect the initiation and development of PD and have been associated with the potential etiological role of PD in CVD and other chronic conditions. A potential etiological link between PD and CVD may have important public health implications as both the exposure (PD and the outcomes (CVD are highly prevalent in industrialized societies. In situations in which both the exposure and the outcome are highly prevalent even modest associations, like those observed in the studies reporting on the link between PD and CVD outcomes, may have relevance. There are  not  definite data on the effect of periodontal treatment on CVD clinical outcomes (either in primary or secondary prevention however it should be pointed out that the limited (both in terms of numbers and study design experimental evidence in humans suggests a possible beneficial effect of periodontal treatment of indices of functional and structural vascular health.

  13. 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

  14. 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.

  15. 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.

  16. Preparation and catalytic performance of monolayer-dispersed Pd/Ni bimetallic catalysts for hydrogenation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Pd/Ni bimetallic catalysts were prepared by replacement reactions,characterized by X-ray diffraction,CO chemisorption and H2 temperature-programmed desorption,and evaluated for hydrogenation of cyclohexene,styrene and acetone.The results show that Pd atoms are monolayer-dispersed on the Ni surface in these Pd/Ni catalysts.Consequently,Pd/Ni catalysts are much more active than Pd/Ni and Pd/γ-Al2O3 with the same Pd loading prepared by the conventional impregnation method.

  17. 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.

  18. 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

    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...... 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...... 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...

  19. 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.

  20. 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.

  1. Phase Equilibria in System Pd-Au-Sn and Pd-Cu-Sn at 800℃ and 500℃

    Institute of Scientific and Technical Information of China (English)

    KABANOVA E. G.; KAREVA M. A.; KUZNETSOV V. N.; VASEKIN V. V.

    2012-01-01

    Alloys of Pd-Au-Sn and Pd-Cu-Sn systems were investigated using metallography,electron microprobe,X-ray diff action and DTA.Partial isothermal sections were plots at 800℃ and 500℃.Ternary τ-phase having tetragonal structure has been established in each systems.The region of existence of phases in equilibrium with the solid solution based on palladium.

  2. In vitro dynamic pharmacokinetic/pharmacodynamic(PK/PD) modeling and PK/PD cutoff of cefquinome against Haemophilus parasuis

    OpenAIRE

    Xiao, Xia; Sun, Jian; Chen, Yi; Huang, Rui-Juan; Huang, Ting; Qiao, Guilin Gary; Zhou, Yu-Feng; Liu, Ya-Hong

    2015-01-01

    Background Haemophilus parasuis (H. parasuis) causes Glässer’s disease and multisystem infectious disease. It is one of the major causes of nursery mortality in swine herds. Cefquinome (CEQ) is proposed for the treatment of pigs against respiratory tract infection. However, few studies have investigated the PK/PD characteristics and PK/PD cutoff of this drug against H. parasuis. Results A total of 213 H. parasuis strains were isolated from diseased pigs in China. The minimal inhibitory concen...

  3. Dissociative adsorption of methane on surface oxide structures of Pd-Pt alloys

    OpenAIRE

    Dianat, Arezoo; Seriani, Nicola; Ciacchi, Lucio Colombi; Pompe, Wolfgang; Cuniberti, Gianaurelio; Bobeth, Manfred

    2010-01-01

    The dissociative adsorption of methane on variously oxidized Pd, Pt and Pd-Pt surfaces is investigated using density-functional theory, as a step towards understanding the combustion of methane on these materials. For Pd-Pt alloys, models of surface oxide structures are built on the basis of known oxides on Pd and Pt. The methane adsorption energy presents large variations depending on the oxide structure and composition. Adsorption is endothermic on the bare Pd(111) metal surface as well as ...

  4. Growth of Ag nanocrystals on multiwalled carbon nanotubes and Ag-carbon nanotube interaction

    Institute of Scientific and Technical Information of China (English)

    WANG ZhenXia; LI XinNian; REN CuiLan; YONG ZhenZhong; ZHU JianKang; LUO WenYun; FANG XiaoMing

    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 ex-perimental 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Effect of additional element and heat treating temperature on micro-structure and mechanical behavior of Ag alloy thin film

    Institute of Scientific and Technical Information of China (English)

    JU Dong-ying; ISHIGURO S; ARIZONO T; HASEGAWA K

    2006-01-01

    For Ag alloy film used for the storage media,it is required to have heat-resistance,anti-constant temperature and anti-constant humidity characteristics,corrosion resistance,while high reflectivity over Al is maintained. An Ag alloy thin film (additive element Pd,Cu,P) was created on glass substrates,and various heat treatment was conducted. Then,fine structure was observed on this thin film using AFM,and fine structure evaluation of the inside was carried out by the in-plane diffractometry and X-ray diffractometry,and in addition,residual stress analysis was carried out. These results were compared and were examined,and fine structure and physical property in a metallic thin film were evaluated,and usefulness of evaluation method was verified.

  11. 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.

  12. Enhanced Methanol Tolerance of Highly Pd rich Pd-Pt Cathode Electrocatalysts in Direct Methanol Fuel Cells

    International Nuclear Information System (INIS)

    Methanol crossover critically restricts the practical application of direct methanol fuel cells (DMFCs). To resolve this crucial difficulty from the standpoint of electrocatalysis, an electrode material having high activity for the oxygen reduction reaction and low activity for the methanol oxidation reaction compared to widely used Pt-based electrodes is needed for DMFC cathodes. In this research carbon-supported Pd-rich Pd–Pt bimetallic nanoparticle electrocatalysts with 60 wt.% metal content were prepared for this purpose by sodium borohydride reduction of metal chlorides. The physical features of the prepared nanoparticles were investigated by transmission electron microscopy, energy dispersive X-ray spectroscopy, atomic absorption spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption near edge spectroscopy. Methanol tolerance was tested by means of rotating disk electrode (RDE) voltammetry using oxygen-saturated methanol-containing electrolyte solutions as the anode fuel for DMFC unit cell performance tests. In the RDE measurements, Pd-rich electrocatalysts (carbon-supported Pd19Pt1 nanoparticles) showed excellent methanol tolerance compared with Pd-free Pt electrocatalyst. When Pd19Pt1 nanoparticles were used as a DMFC cathode catalyst, unit cell performance tests showed that the i-V curves of the Pd19Pt1 electrocatalyst decreased slightly with increasing methanol concentration, while that of the Pt electrocatalyst decreased rapidly. The results in a liquid-feed DMFC unit cell test were in good agreement with the methanol tolerant characteristics identified in the RDE measurements

  13. 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.

  14. PD-L1 expression in human cancers and its association with clinical outcomes.

    Science.gov (United States)

    Wang, Xin; Teng, Feifei; Kong, Li; Yu, Jinming

    2016-01-01

    PD-L1 is an immunoinhibitory molecule that suppresses the activation of T cells, leading to the progression of tumors. Overexpression of PD-L1 in cancers such as gastric cancer, hepatocellular carcinoma, renal cell carcinoma, esophageal cancer, pancreatic cancer, ovarian cancer, and bladder cancer is associated with poor clinical outcomes. In contrast, PD-L1 expression correlates with better clinical outcomes in breast cancer and merkel cell carcinoma. The prognostic value of PD-L1 expression in lung cancer, colorectal cancer, and melanoma is controversial. Blocking antibodies that target PD-1 and PD-L1 have achieved remarkable response rates in cancer patients who have PD-L1-overexpressing tumors. However, using PD-L1 as an exclusive predictive biomarker for cancer immunotherapy is questionable due to the low accuracy of PD-L1 immunohistochemistry staining. Factors that affect the accuracy of PD-L1 immunohistochemistry staining are as follows. First, antibodies used in different studies have different sensitivity. Second, in different studies, the cut-off value of PD-L1 staining positivity is different. Third, PD-L1 expression in tumors is not uniform, and sampling time and location may affect the results of PD-L1 staining. Therefore, better understanding of tumor microenvironment and use of other biomarkers such as gene marker and combined index are necessary to better identify patients who will benefit from PD-1/PD-L1 checkpoint blockade therapy. PMID:27574444

  15. Production hall of YMOS AG; Produktionshalle YMOS AG

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1997-06-01

    In early 1996 YMOS AG opted for the construction of a high-tech injection moulding factory. The building complex consists of a production hall bordered by a high-shelved warehouse. The factory concept underscores the the significance and technical prowness of the YMOS company as well the continuously growing quality demands it is having to meet. The buildings have been constructed in steel using grey metallic trapezoidal corrugated sheet (sandwich design). The overall concept for this industrial object was guided solely by economic considerations. (orig./HW) [Deutsch] Anfang des Jahres 1996 entschied man sich fuer den Neubau einer hochmodernen Kunststoffspritzerei. Der Gebaeudekomplex besteht aus der Produktionhalle mit angrenzendem Hochregallager. Das Konzept unterstreicht sowohl die Bedeutung und technische Leistungsfaehigkeit des Unternehmens YMOS als auch die immer staerker werdenden Qualitaetsanforderungen. Die Gebaeude wurden in Stahlkonstruktion mit metallisch grauem Trapezblech (Sandwichbauweise) errichtet. Massstab fuer die Gesamtkonzeption dieses Industrieobjektes waren rein wirtschaftliche Gesichtspunkte. (orig./HW)

  16. Antibacterial biodegradable Mg-Ag alloys

    Directory of Open Access Journals (Sweden)

    D Tie

    2013-06-01

    Full Text Available The use of magnesium alloys as degradable metals for biomedical applications is a topic of ongoing research and the demand for multifunctional materials is increasing. Hence, binary Mg-Ag alloys were designed as implant materials to combine the favourable properties of magnesium with the well-known antibacterial property of silver. In this study, three Mg-Ag alloys, Mg2Ag, Mg4Ag and Mg6Ag that contain 1.87 %, 3.82 % and 6.00 % silver by weight, respectively, were cast and processed with solution (T4 and aging (T6 heat treatment.The metallurgical analysis and phase identification showed that all alloys contained Mg4Ag as the dominant β phase. After heat treatment, the mechanical properties of all Mg-Ag alloys were significantly improved and the corrosion rate was also significantly reduced, due to presence of silver. Mg(OH2 and MgO present the main magnesium corrosion products, while AgCl was found as the corresponding primary silver corrosion product. Immersion tests, under cell culture conditions, demonstrated that the silver content did not significantly shift the pH and magnesium ion release. In vitro tests, with both primary osteoblasts and cell lines (MG63, RAW 264.7, revealed that Mg-Ag alloys show negligible cytotoxicity and sound cytocompatibility. Antibacterial assays, performed in a dynamic bioreactor system, proved that the alloys reduce the viability of two common pathogenic bacteria, Staphylococcus aureus (DSMZ 20231 and Staphylococcus epidermidis (DSMZ 3269, and the results showed that the killing rate of the alloys against tested bacteria exceeded 90%. In summary, biodegradable Mg-Ag alloys are cytocompatible materials with adjustable mechanical and corrosion properties and show promising antibacterial activity, which indicates their potential as antibacterial biodegradable implant materials.

  17. 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

    2014-01-01

    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.

  18. The Pd distribution and Cu flow pattern of the Pd-plated Cu wire bond and their effect on the nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yu-Wei; Wang, Ren-You; Ke, Wun-Bin; Wang, I-Sheng [Department of Materials Science and Engineering, National Cheng Kung University, 1, Ta-Hsueh Rd., Tainan 701, Taiwan (China); Chiu, Ying-Ta [Department of Materials Science and Engineering, National Cheng Kung University, 1, Ta-Hsueh Rd., Tainan 701, Taiwan (China); Central Product Solutions, Advances Semiconductor Engineering, Inc., 26 Chin 3rd Rd., Nantze Export Processing Zone, Kaohsiung 811, Taiwan (China); Lu, Kuo-Chang, E-mail: gkclu@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, 1, Ta-Hsueh Rd., Tainan 701, Taiwan (China); Lin, Kwang-Lung, E-mail: matkllin@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, 1, Ta-Hsueh Rd., Tainan 701, Taiwan (China); Lai, Yi-Shao [Central Product Solutions, Advances Semiconductor Engineering, Inc., 26 Chin 3rd Rd., Nantze Export Processing Zone, Kaohsiung 811, Taiwan (China)

    2012-05-01

    Highlights: Black-Right-Pointing-Pointer Pd distribution in Pd-plated Cu wires reveals the whirlpool flow pattern of Cu. Black-Right-Pointing-Pointer The mechanisms of the Cu flow behavior and Pd distribution are proposed. Black-Right-Pointing-Pointer At Pd-rich phases, small voids formed and followed the direction of Cu flow. Black-Right-Pointing-Pointer Nanoindentation studies show the Cu ball bond is harder in regions with Pd. - Abstract: The Pd plating on the 20 {mu}m Cu wire dissolves in the free air ball (FAB) and the Cu ball bond during the wire bonding process without forming intermetallic compounds. The limiting supply of Pd and the short bonding process, 15 ms of thermosonic bonding, result in uneven distribution of Pd in the as produced Cu ball bond. Also, the Pd-rich phase may accompany small voids formed within the FAB and the wire bond, and following the direction of semi-solid Cu flow. The Pd distribution, as evidenced by the focused ion beam (FIB) and wavelength dispersive X-ray spectroscopy (WDS) mapping, reveals the whirlpool flow pattern of Cu within the FAB and the ball bond. Pd distributes within the copper ball through convective transport by the copper flow. Additionally, hardness measurements by nanoindentation testing show that the Cu ball bond is harder in the regions where Pd exists.

  19. Glycerol electro-oxidation in alkaline medium using Pd/C and PdSn/C electrocatalysts prepared by electron beam irradiation

    International Nuclear Information System (INIS)

    Carbon-supported metal nanoparticles were prepared for fuel cell applications by radiation-induced reduction of metal ions precursors. Pd/C and PdSn/C electrocatalysts (Pd:Sn atomic ratio 90:10), prepared by using electron beam irradiation, were tested for glycerol electro-oxidation in single alkaline direct glycerol fuel cell (ADGFC). EDX analysis showed that the Pd:Sn atomic ratio is very similar to the nominal one. X-ray diffractograms of PdSn/C electrocatalyst showed the presence of Pd (fcc) phase. Cyclic voltammetry (CV) indicated that Pd/C and PdSn/C electrocatalysts have good activity for glycerol electro-oxidation, at room temperature. Experiments with single ADGFC were carried out from 60 to 90 deg C, using Pd/C and PdSn/C electrocatalysts and glycerol 2.0 mol.L-1, as fuel. The best performance was obtained at 85 deg C, for both electrocatalysts. The Pd/C and PdSn/C electrocatalysts showed similar performance (34 mW cm-2), at 85 deg C. (author)

  20. Glycerol electro-oxidation in alkaline medium using Pd/C and PdSn/C electrocatalysts prepared by electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Geraldes, Adriana Napoleao; Silva, Dionisio Fortunato da; Pino, Eddy Segura; Spinace, Estevan Vitorio; Oliveira Neto, Almir; Linardi, Marcelo, E-mail: drinager@ig.com.br, E-mail: dfsilva@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Santos, Mauro Coelhos dos [Universidade Federal do ABC (LEMN/UFABC), Santo Andre, SP (Brazil)

    2013-07-01

    Carbon-supported metal nanoparticles were prepared for fuel cell applications by radiation-induced reduction of metal ions precursors. Pd/C and PdSn/C electrocatalysts (Pd:Sn atomic ratio 90:10), prepared by using electron beam irradiation, were tested for glycerol electro-oxidation in single alkaline direct glycerol fuel cell (ADGFC). EDX analysis showed that the Pd:Sn atomic ratio is very similar to the nominal one. X-ray diffractograms of PdSn/C electrocatalyst showed the presence of Pd (fcc) phase. Cyclic voltammetry (CV) indicated that Pd/C and PdSn/C electrocatalysts have good activity for glycerol electro-oxidation, at room temperature. Experiments with single ADGFC were carried out from 60 to 90 deg C, using Pd/C and PdSn/C electrocatalysts and glycerol 2.0 mol.L{sup -1}, as fuel. The best performance was obtained at 85 deg C, for both electrocatalysts. The Pd/C and PdSn/C electrocatalysts showed similar performance (34 mW cm{sup -2}), at 85 deg C. (author)

  1. 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.

  2. 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.

  3. An ab-initio study of silicon adsorption on metallic surfaces (Au/Ag): Novel perspective to explore chemical bonding

    Science.gov (United States)

    Chakraborty, S.; Ghaisas, S. V.; Majumder, C.

    2012-07-01

    We report a first-principle investigation of the structure and electronic properties of small Sin (n = 1-6,9) clusters deposited on the Au(111) and Ag(111) surfaces. The calculations were performed using a plane wave based pseudopotential method under the framework of density functional theory. The results reveal the preference of Si atom to be adsorbed on the h.c.p. site of the metal (111) surfaces with strong binding energy. We study monolayer (ML) deposition as well as the cluster deposition on both the surfaces. The clusters introduce interlayer forces in the adsorbate. Based on PDOS (projected density of states) analysis it is found that Si atoms acquire charges from the Au/Ag surface. The binding energies are consistent with the known cohesive energy of Ag and Au silicides. The planar Sin cluster deposition on metal surfaces show that Au provides an adjustable surface with relatively strong Au-Si interaction while Ag-Si relatively weak interaction leading to dimerization of Si. The strong bonding with the surface atoms is a result of p-d hybridization. Some of the 3-D clusters show shape distortions after deposition on metal surfaces. This leads to internal stresses after deposition. A statistical parameter is defined over PDOS. It helps to measure the state delocalization in energy. Implications of the Si-Metal interaction on the initial stages of growth are discussed.

  4. 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.

  5. The AGS Booster vacuum systems

    International Nuclear Information System (INIS)

    The AGS Booster is a synchrotron for the acceleration of both protons and heavy ions. The design pressure of low 10-11 mbar is required to minimize beam loss of the partially stripped heavy ions. To remove contaminants and to reduce outgassing, the vacuum chambers and the components located in them will be chemically cleaned, vacuum fired, baked then treated with nitric oxide. The vacuum sector will be insitu baked to a minimum of 200 degree C and pumped by the combination of sputter ion pumps and titanium sublimation pumps. This paper describes the design and the processing of this ultra high vacuum system, and the performance of some half-cell vacuum chambers. 9 refs., 7 figs

  6. 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.

  7. CTC immune escape mediated by PD-L1.

    Science.gov (United States)

    Wang, Xuefei; Sun, Qiang; Liu, Qiaofei; Wang, Changjun; Yao, Ru; Wang, Yimin

    2016-08-01

    Breast cancer is the most common malignant tumor in women around the world. Most breast cancer-related deaths are from CTC (circulating tumor cells) metastasis. CTC is associated with the breast cancer patients' prognosis. But recently, circulating clusters were found and its metastasis and tumor formation ability is 23-50 times as CTC. However, its mechanism has not been clarified. These days, researchers have successfully completed CTC cluster separation, CTC cell culture, and PD-L1 was found to be related with histological grading of tumor. Meanwhile, the high expression of PD-L1 in CTC surface has also been reported. Since PD-L1 can mediate Treg to play the role of immunosuppression, we propose that CTC with positive PD-L1 is easier to connect PD-L1, immune cells (Treg regulatory T cells, MDSC bone marrow inhibitory cells) and CK cytokines etc. On one hand, Treg cells can protect CTC from being attacked by the immune system through the immunosuppression, on the other hand, they can weaken CTL killing ability and trigger more MDSC. Finally, CTC formed the metastatic lesion. PMID:27372873

  8. 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.

  9. 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 ...

  10. Expression of Programmed Cell Death 1 Ligands (PD-L1 and PD-L2) in Histiocytic and Dendritic Cell Disorders.

    Science.gov (United States)

    Xu, Jie; Sun, Heather H; Fletcher, Christopher D M; Hornick, Jason L; Morgan, Elizabeth A; Freeman, Gordon J; Hodi, F Stephen; Pinkus, Geraldine S; Rodig, Scott J

    2016-04-01

    Programmed cell death 1 ligands 1 and 2 (PD-L1 and PD-L2) are cell surface proteins expressed by activated antigen-presenting cells and by select malignancies that bind PD-1 on T cells to inhibit immune responses. Antibodies targeting PD-1 or PD-L1 elicit antitumor immunity in a subset of patients, and clinical response correlates with PD-1 ligand expression by malignant or immune cells within the tumor microenvironment. We examined the expression of PD-1 ligands on subsets of antigen-presenting cells and 87 histiocytic and dendritic cell disorders including those that are benign, borderline, and malignant. Within reactive lymphoid tissue, strong PD-L1 is detected on most macrophages, subsets of interdigitating dendritic cells, and plasmacytoid dendritic cells, but not on follicular dendritic cells or Langerhans cells. Macrophage/dendritic cell subsets do not express discernible PD-L2. Seven of 7 cases of sarcoidosis (100%), 6 of 6 cases of histiocytic necrotizing lymphadenitis (Kikuchi-Fujimoto disease) (100%), 2 of 11 cases of Rosai-Dorfman disease (18%), and 3 of 15 cases of Langerhans cell histiocytosis (20%) exhibited positivity for PD-L1. All cases of sarcoidosis were also positive for PD-L2. Seven of 14 histiocytic sarcomas (50%), 2 of 5 interdigitating dendritic cell sarcomas (40%), 10 of 20 follicular dendritic cell sarcomas (50%), and none of 9 blastic plasmacytoid dendritic cell neoplasms were positive for PD-L1. Eleven of 20 (55%) follicular dendritic cell sarcomas were also positive for PD-L2. PD-L1 and PD-L2 are useful new markers for identifying select histiocyte and dendritic cell disorders and reveal novel patient populations as rational candidates for immunotherapy. PMID:26752545

  11. Formation of Catalyst Model Dispersed of Pd on a thin MgO(100)

    Science.gov (United States)

    Baara, F.; Chemam, A.

    2016-04-01

    The nucleation kinetics or the formation of a catalyst model dispersed for the system Pd/thin MgO (100) are calculated by developing many programs using Fortran software. This simulation is based upon parameters studied in situ by transmission electron microscopy (TEM), related to the first quantitative study on the nucleation and the growth. Palladium nanoparticles deposited on thin MgO are tested in the temperature range 573-1073 K and deposition time of 1000 s. The nucleation kinetics are interpreted according to the theory of random nucleation. The general scheme is consisting of three stages namely, nucleation, growth and coalescence. The saturation density of clusters decreases when the substrate temperature increases following Arrhenius law. This behavior is in agreement with a recent AFM study for Ag/MgO and Au/MgO. The phenomenon of coalescence is explained via island migration process. It is shown that the coalescence occurs more rapidly when the substrate temperature is high.

  12. The examination system for Japanese WOL and DMW PD qualification test

    International Nuclear Information System (INIS)

    In Japan, the 1st Performance Demonstration (PD) qualification examination started in March of 2006 and was operated by the Performance Demonstration (PD) center of Central Research Institute of Electric Power Industry (CRIEPI). The first application of Japanese PD system is crack depth sizing on stainless steel piping welds. PD center is planning to start weld overlay (WOL) PD examination as a second step, and dissimilar weld (DMW) PD examination as third step. In particular, WOL PD examination includes crack detection and length / depth sizing because it is necessary to detect the crack tip on detection and length sizing test. In the detection test, it is difficult to judge miss call or false call. Therefore ASME code and NDIS0603 introduced the idea of 'Grading Unit'. This paper reports the readiness of WOL-PD and DMW-PD test and explains grading unit and acceptance criteria. (author)

  13. A case study of complex metallic alloy phases: Structure and disorder phenomena of Mg-Pd compounds

    OpenAIRE

    2005-01-01

    Abstract The Mg-Pd phase diagram has been re-determined in the range 60 to 100 at-% Mg. The existence of the intermediate phases Mg6Pd (?), Mg57Pd13 (?), Mg56.4Pd13.5 (?), Mg306Pd77 (?), Mg78.5Pd21.5 (?), Mg3Pd (?), Mg5Pd2 (?) and Mg2Pd (?) has been reconfirmed. The ?-phase melts congruently whereas the CMAs ?, ?, ? and ? form in a cascade of peritectoid and peritectic reactions in a narrow window of approx. 30 ?C and 3 at-%. It is assumed that the stability of the Mackay icosahedr...

  14. Synthesis of PdO/MCM-41 nanocomposites using trans-[PdCl2(PEt3)2] as the source of metal

    International Nuclear Information System (INIS)

    Three PdO/MCM-41 nanocomposites containing PdO species that are dispersed on an MCM-41 support have been prepared using trans-[PdCl2(PEt3)2] as the source of metal. Thermal gravimetric analysis of the decomposition of this complex in air reveals a remarkable mass loss of all nonmetallic elements centered at 300 deg. C. The materials were characterized with X-ray powder diffraction (XRPD), nitrogen sorption and TEM, which showed that the PdO nanoparticles were present inside the pores of MCM-41. XRPD analysis confirms formation of PdO (palladinite) nanocrystals, as the sole crystalline phase present in the nanocomposites.

  15. Agent planning in AgScala

    Science.gov (United States)

    Tošić, Saša; Mitrović, Dejan; Ivanović, Mirjana

    2013-10-01

    Agent-oriented programming languages are designed to simplify the development of software agents, especially those that exhibit complex, intelligent behavior. This paper presents recent improvements of AgScala, an agent-oriented programming language based on Scala. AgScala includes declarative constructs for managing beliefs, actions and goals of intelligent agents. Combined with object-oriented and functional programming paradigms offered by Scala, it aims to be an efficient framework for developing both purely reactive, and more complex, deliberate agents. Instead of the Prolog back-end used initially, the new version of AgScala relies on Agent Planning Package, a more advanced system for automated planning and reasoning.

  16. 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.

  17. 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...

  18. Phase transition in odd-N Pd-isotopes

    Science.gov (United States)

    Zhou, Hou-Bing; Dong, Guo-Xiang; Sun, Xiao-Jun; Xu, Fu-Rong

    2015-11-01

    Phase transition in odd-N isotopes 99,101,103Pd are investigated via the E-GOS (E-Gamma Over Spin) curves, which strongly suggest a structure evolution from vibration to rotation along the yrast lines with increasing spin. Theoretical calculations have been performed for the ground state bands of 99,101,103Pd in the framework of the cranked shell model (CSM) and the alignment properties observed experimentally are analyzed employing this model. The results show that the phase transition in the ground state bands of 99,101,103Pd can be interpreted as the valence nucleons start to occupy the g9/2 proton orbitals with increasing spin which would polarize the core to a small, but rigid quadrupole deformation. Supported by Natural Science Foundation of Guangxi (2014jjBA10016, 2014jjDA10012) and National Natural Science Foundation of China (11465005)

  19. 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

  20. 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.

  1. PdZn catalysts prepared by washcoating microstructured reactors

    Energy Technology Data Exchange (ETDEWEB)

    Pfeifer, P.; Schubert, K. [Forschungszentrum Karlsruhe GmbH, Institute for Micro Process Engineering, POB 3640, 76021 Karlsruhe (Germany); Liauw, M.A.; Emig, G. [University Erlangen-Nurnberg, LTC1, Egerlandstrasse 3, 91058 Erlangen (Germany)

    2004-08-30

    Methanol steam reforming is an option for dynamic hydrogen generation in automotive fuel cell systems. Microstructured reactors with small channels (100{mu}mx100{mu}m) are being studied. A washcoating procedure applying dispersed ZnO nanoparticles to the microchannel walls was adapted to the PdZn catalyst system. The catalyst layer showed no significant differences during X-ray diffraction and temperature-programmed oxidation and reduction experiments for examination of oxidation state and alloy formation compared with other PdZn systems reported in the literature. Chemisorption with different adsorbates and X-ray backscattering were used for gathering detailed information on PdZn dispersion, diameter and shape with respect to the preparation parameters. Catalytic experiments yielded a relationship between the catalyst properties and the catalytic activity, degradation and secondary reactions.

  2. 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...... a measured signal at the cable terminations to a specific PD-amplitude and location on the cable, the attenuation and the transmission speed of PD-pulses on the cable have to be known. Consequently, the main parameter to be determined is the complex propagation constant which consists of the attenuation...... and phase constants. A method to estimate this propagation constant, based on high frequency measurements, will be presented and will be applied to different cable types under different conditions. The influence of temperature and test voltage was investigated. The relevance of the results for cable...

  3. 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.

  4. Ethanol electro-oxidation in alkaline medium using Pd/c and PdRh/C electrocatalysts prepared by electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Dionisio Furtunato da; Geraldes, Adriana Napoleao; Pino, Eddy Segura; Spinace, Estevam Vitorio; Oliveira Neto, Almir; Linardi, Marcelo, E-mail: dfsilva@ipen.br, E-mail: drinager@ig.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    In this study, carbon-supported Pd (Pd/C) and bimetallic PdRh (Pd:Rh 90:10 atomic ratio) (PdRh/C) electrocatalysts were prepared using electron beam irradiation. The morphology and composition of the obtained materials were characterized by Cyclic voltammetry (VC), Chronoamperometry (CA), Energy dispersive X-ray (EDX), X-ray Diffraction (XRD) and Thermo-gravimetric analysis (TGA). The catalytic activities of the electrocatalysts toward the ethanol electro-oxidation were evaluated in alkaline medium in a single alkaline direct ethanol fuel cell (ADEFC), in a range temperature of 50 to 85 deg C. The best performances were obtained at 85 deg C (25 mW.cm{sup -2}) and 75 deg C (38 mW.cm{sup -2}) for Pd/C and PdRh/C electrocatalysts, respectively. The XRD of the PdRh/C electrocatalyst showed the presence of Pd-rich (fcc) phase. CV and CA experiments showed that PdRh/C electrocatalyst demonstrated superior activity toward ethanol electro-oxidation at room temperature, compared to Pd/C electrocatalyst. (author)

  5. 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.

  6. 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.

  7. Nucleation and growth mechanism of Ag precipitates in a CuAgZr alloy

    Energy Technology Data Exchange (ETDEWEB)

    Piyawit, W.; Xu, W.Z. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Mathaudhu, S.N. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Materials Science Division, US Army Research Office, Research Triangle Park, NC 27709 (United States); Freudenberger, J. [IFW Dresden, Institute for Metallic Materials, P.O. 270116, D-01171 Dresden (Germany); Technische Universität Bergakademie Freiberg, Institute of Materials Science, Gustav-Zeuner-Str. 5, 09959 Freiberg (Germany); Rigsbee, J.M. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Zhu, Y.T., E-mail: ytzhu@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695 (United States)

    2014-07-29

    CuAgZr alloy is a variant of the CuAg alloy that is developed for high strength and high conductivity applications. Its strengthening is accomplished mainly by the precipitation of Ag precipitates, which tend to align on {111} planes in the Cu matrix. This alignment has been reported to be caused by stacking faults on {111} planes. Contrary to these reports, this research presents evidence for Ag precipitates formation on {111} planes due to the minimization of elastic energy. The Ag precipitates were formed by clustering of Ag atoms while maintaining the fcc crystal structure of the matrix. They have faceted {111} interfaces with the matrix. The thickening of precipitates appears to be by the ledge growth mechanism, which is resulted in by misfit dislocation networks on the interface.

  8. 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.

  9. Ag induced electromagnetic interference shielding of Ag-graphite/PVDF flexible nanocomposites thinfilms

    Science.gov (United States)

    Kumaran, R.; Alagar, M.; Dinesh Kumar, S.; Subramanian, V.; Dinakaran, K.

    2015-09-01

    We report Ag nanoparticle induced Electromagnetic Interference (EMI) shielding in a flexible composite films of Ag nanoparticles incorporated graphite/poly-vinylidene difluoride (PVDF). PVDF nanocomposite thin-films were synthesized by intercalating Ag in Graphite (GIC) followed by dispersing GIC in PVDF. The X-ray diffraction analysis and the high-resolution transmission electron microscope clearly dictate the microstructure of silver nanoparticles in graphite intercalated composite of PVDF matrix. The conductivity values of nanocomposites are increased upto 2.5 times when compared to neat PVDF having a value of 2.70 S/cm at 1 MHz. The presence of Ag broadly enhanced the dielectric constant and lowers the dielectric loss of PVDF matrix proportional to Ag content. The EMI shielding effectiveness of the composites is 29.1 dB at 12.4 GHz for the sample having 5 wt. % Ag and 10 wt. % graphite in PVDF.

  10. Ag-rich precipitates formation in the Cu–11%Al–10%Mn–3%Ag alloy

    International Nuclear Information System (INIS)

    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 α1 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

  11. 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.

  12. Computation and comparison of Pd-based membrane reactor performances for water gas shift reaction and isotope swamping in view of highly tritiated water decontamination

    International Nuclear Information System (INIS)

    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

  13. 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.

  14. Fuzzy Cosets and Quotient Fuzzy AG-subgroups

    OpenAIRE

    Amanullah,; Ahmad, Imtiaz; Shah, Muhammad

    2014-01-01

    In this paper we extend the concept of fuzzy AG-subgroups. We introduce some results in normal fuzzy AG-subgroups. We define fuzzy cosets and quotient fuzzy AG-subgroups, and prove that the sets of their collection form an AG-subgroup and fuzzy AG-subgroup respectively. We also introduce the fuzzy Lagrange's Theorem of AG-subgroup. It is known that the condition $\\mu(xy)=\\mu(yx)$ holds for all $x,y$ in fuzzy subgroups if $\\mu$ is normal, but in fuzzy AG-subgroup we show that it holds without ...

  15. Clinical Research Progress of Anti PD-1/PD-L1 Monoclonal Antibody in the Treatment of Lung Cancer%抗PD-1/PD-L1单抗治疗肺癌临床研究进展

    Institute of Scientific and Technical Information of China (English)

    黄志煜; 李晖(综述); 范云(审校)

    2015-01-01

    近期,抗程序性死亡分子1(programmed death-1, PD-1)/PD-1配体(PD-1 ligand, PD-L1)单抗在晚期非小细胞肺癌的治疗中纷纷取得了突破性进展,相关研究迅速覆盖到肺癌的其他领域,如小细胞肺癌、局部晚期非小细胞肺癌;并且开始尝试与现有治疗手段的各种组合,如联合化疗、靶向药物及放疗等。但是,仍有许多问题有待解决,如寻找理想的预测疗效的生物标记物、探索不同的联合治疗模式、明确原发及继发耐药的机制等等。随着这些问题的相继解决,抗PD-1/PD-L1单抗在肺癌的治疗中将会有更加广阔的应用空间。%Recently, the immune checkpoint inhibitors which targetprogrammed death-1 (PD-1)/PD-1 ligand (PD-L1) have made a breakthrough in the treatment of advanced non-small cell lung cancer. Researches on immune check-point inhibitors have been rapidly implemented in various types of lung cancer, such as small cell lung cancer and locally ad-vanced non-small cell lung cancer. hTese inhibitors have been applied in combination with other treatment strategies, including chemotherapy, targeting therapy and radiotherapy. However, there are still many problems to be solved, such as searching for ideal biomarkers, exploring different combination treatment models, and identifying the potential mechanisms of primary or secondary drug resistance. Along with these problems to be successfully solved, the immune checkpoint inhibitors will have broader applications in lung cancer therapy.

  16. 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.

  17. 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.

  18. RHIC/AGS Online Model Environments: Experiences and Design for AGS Modeling

    International Nuclear Information System (INIS)

    The RHIC/AGS online modeling environment, a general client-server modeling package that supports cdev and straightforward integration of diverse computational modeling engines (CMEs), is being adapted to model the AGS and Booster at BNL. This implementation uses a version of MAD modified at BNL that allows traditional lattice structure analysis, single pass beam line analysis, multi-particle tracking, interactive graphics, and the use of field maps. The on-line model system is still under development, a real working prototype exists and is being tested. This paper describes the system and experience with its design and use for AGS and AGS Booster online modeling

  19. Immunostimulatory activities of dendritic cells loaded with adenovirus vector carrying HBcAg/HBsAg

    OpenAIRE

    Jia, Hongyu; Li, Chunling; Zhang, Yimin; Yu, Liang; Xiang, Dairong; Liu, Jun; Chen, Fengzhe; Han, Xiaochun

    2015-01-01

    Objective: This study is to investigate the immunostimulatory activities of dendritic cells (DCs) transfected with HBcAg and/or HBsAg recombinant adenovirus (rAd). Methods: DCs were transfected with rAd (DC/Ad-C+Ad-S, DC/Ad-C, and DC/Ad-S), or pulsed with HBcAg antigen (DC/HBcAg). Flow cytometry was used to detect the phenotype of DCs and the cytokine production of T lymphocytes. Mice were vaccinated with DCs transfected with rAd or pulsed with antigen, and DNA vaccine. Mixed lymphocyte react...

  20. 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...

  1. 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.

  2. Aleaciones de Ag/Pd para su uso como metalizaciones internos en condensadores cerámicos multicapa

    OpenAIRE

    Villegas, Marina

    1995-01-01

    Los principales objetivos que permiten el futuro desarrollo de condensadores cerámicos de elevadas prestaciones son reducir el coste de los electrodos internos y la reducción de su espesor sin sacrificar su rendimiento. Debido a que el funcionamiento del electrodo interno influye fuertemente sobre el funcionamiento final de los condensadores cerámicos multicapa (CCM), es necesario conocer y entender todas las posibles interacciones de dichos electrodos con el material dieléctrico que constitu...

  3. 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.

  4. 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...

  5. 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...

  6. 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.

  7. 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

  8. Lattice location of implanted Ag in Si

    CERN Document Server

    Wahl, U; Vantomme, A

    2002-01-01

    The lattice location of implanted silver in Si was studied by means of the emission channeling technique. Following 60 keV room temperature implantation of radioactive $^{111}$Ag at a dose of 2-3 $\\times 10^{12}$ cm$^{-2}$, we identify around 30% of Ag on near-substitutional sites (around 0.45 from ideal S-sites). Upon annealing at 200-300°C, the fraction on near-S sites reaches a maximum around 60-80%. For higher annealing temperatures it decreases again and at 600°C Ag starts to diffuse out of the Si samples. We estimate the activation energy for the dissociation of near-substitutional Ag to be 1.8-2.2 eV. The experimental results are compared to those of Cu in Si, and common features and characteristic differences in the behavior of the two group 1B metals are discussed.

  9. Clinical Research Progress of Anti PD-1/PD-L1 Monoclonal Antibody in the Treatment of Lung Cancer

    Directory of Open Access Journals (Sweden)

    Zhiyu HUANG

    2015-11-01

    Full Text Available Recently, the immune checkpoint inhibitors which target programmed death-1 (PD-1/PD-1 ligand (PD-L1 have made a breakthrough in the treatment of advanced non-small cell lung cancer. Researches on immune checkpoint inhibitors have been rapidly implemented in various types of lung cancer, such as small cell lung cancer and locally advanced non-small cell lung cancer. These inhibitors have been applied in combination with other treatment strategies, including chemotherapy, targeting therapy and radiotherapy. However, there are still many problems to be solved, such as searching for ideal biomarkers, exploring different combination treatment models, and identifying the potential mechanisms of primary or secondary drug resistance. Along with these problems to be successfully solved, the immune checkpoint inhibitors will have broader applications in lung cancer therapy.

  10. 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.

  11. 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

  12. 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.

  13. 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 invol......, the described fabrication method holds potential for the fabrication of low-cost metal/polymer composite materials for nanoelectronic applications in general. © 2011 The Royal Society of Chemistry....

  14. Radiometric Calibration for AgCam

    OpenAIRE

    Edward Hildum; Lianbo Hu; Hojin Kim; Xiaodong Zhang; Changyong Dou; Doug Olsen

    2010-01-01

    The student-built Agricultural Camera (AgCam) now onboard the International Space Station observes the Earth surface through two linescan cameras with Charge-Coupled Device (CCD) arrays sensitive to visible and near-infrared wavelengths, respectively. The electro-optical components of the AgCam were characterized using precision calibration equipment; a method for modeling and applying these measurements was derived. Correction coefficients to minimize effects of optical vignetting, CCD non-u...

  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. New oxocompounds with planar coordinated Pd2+ BaPdNd2O5 and BaPdSm2O5

    International Nuclear Information System (INIS)

    Single crystals of BaPdNd2O5(A), BaPdSm2O5(B) and BaCuNd2O5(C) were prepared by solid state reaction using BaCl2 as a fusing assistant (A, B) or by high temperature Laser technique (C). X-ray investigations show tetragonal symmetry with A: a=6.7387(5), c=5.9002(25)A, B: a=6.6667(13), c=5.8800(6)A (space group D4sub(4h) - P4/mbm, Z=2). The formerly investigated compound (C) is refined here by single crystal data. (A) and (B) belong to the BaPtNd2O5-type. The results are discussed. (Author)

  17. 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.

  18. 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....

  19. HBcrAg Identifies Patients Failing to Achieve HBeAg Seroconversion Treated with Pegylated Interferon Alfa-2b

    Directory of Open Access Journals (Sweden)

    Hui Ma

    2016-01-01

    Conclusions: Effective antiviral treatment can decrease HBcrAg levels in the serum. The NPVs of HBcrAg for predicting HBeAg seroconversion at 24-week follow-up was 100%, but the PPVs were not satisfactory (all <31%. The serum HBcrAg levels of the patients with HBeAg seroconversion at the end of the 24-week follow-up steadily declined or even became undetectable during the LTFU.

  20. Effect of Pd precursor status on sonochemical surface activation in Cu electroless deposition

    Science.gov (United States)

    Kim, Kanghoon; Jin, Seonok; Kwon, Oh Joong

    2016-02-01

    Pd surface activation via a sonochemical approach was studied by varying Pd precursor status in the aqueous solution. By aging a K2PdCl6 activation solution overnight with added NH4OH, the chlorinated Pd complex was changed to an ammonia-based Pd complex. The Pd surface activation carried out with the NH4OH complexing agent resulted in improved surface condition following Cu electroless deposition. The Cu thin film deposited on a substrate sonochemically activated with the aged, ammonia-based Pd complex showed improved surface roughness and resistivity compared to that for Cu films deposited via two other precursors (chlorinated Pd complex and ammonia-based complex) without aging. In addition, nitrogen purging during sonochemical activation improved Cu film quality.

  1. 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.

  2. Thickness effect on magnetocrystalline anisotropy of Co/Pd(111) films: A density functional study

    Science.gov (United States)

    Jekal, Soyoung; Rhim, S. H.; Kwon, Oryong; Hong, Soon Cheol

    2015-05-01

    In this study, we carried out first-principles calculations on magnetocrystalline anisotropy (MCA) of Co/Pd thin films by adopting two different systems of (i) n-Co/3-Pd and (ii) n-Pd/3-Co. In one system, we vary the thickness of Co layer, fixing the thickness of the Pd layer to 3-monolayers, and in the other system vice versa. MCA is mainly governed by the surface and interface Co atoms, while contributions from other Co atoms are smaller. MCA energy (EMCA) of the Co/Pd thin film shows oscillatory behavior with the thickness of the Co layer, but is insensitive to the thickness of the Pd layer. In particular, the n-Co/3-Pd films of n = 2, 4, and 6 exhibit strong perpendicular MCA of about 1 meV. Our results suggest that controlling the thickness of the Co layer in Co/Pd (111) is crucial in achieving strong perpendicular MCA.

  3. 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...

  4. 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).

  5. Theoretical study of NH3 decomposition on Pd-Cu (1 1 1) and Cu-Pd (1 1 1) surfaces: A comparison with clean Pd (1 1 1) and Cu (1 1 1)

    Science.gov (United States)

    Jiang, Zhao; Qin, Pei; Fang, Tao

    2016-05-01

    The adsorption and successive dehydrogenation mechanisms of NH3 on Pd-Cu (1 1 1) and Cu-Pd (1 1 1) surfaces (the Pd atoms substitution of the first and second layers of Cu (1 1 1) surfaces) have been systematically investigated by density functional theory (DFT) method with a periodic slab model. All possible adsorption configurations of relevant intermediates on Pd-Cu (1 1 1) and Cu-Pd (1 1 1) surfaces are identified. It is revealed that the adsorption configurations and corresponding adsorption energies of adsorbates are slightly changed on Pd-Cu (1 1 1) and Cu-Pd (1 1 1) surfaces. The adsorption energies of NHx(x = 0-3) species exhibit the following trend: NH3 energy path for the complete dehydrogenation of NH3 into adsorbed N and H is identified to explore the dehydrogenation mechanisms on different surfaces. The highest energy barrier and reaction energy on Pd-Cu (1 1 1) surface are greatly reduced to 1.56 and 0.99 eV, implying that the complete dehydrogenation of NH3 on Pd-Cu (1 1 1) surface is favorable both kinetically and thermodynamically, namely, the doped-Pd atoms in the first layer are the reaction active center. Compared to that on clean Pd (1 1 1) and Cu (1 1 1) surfaces, it is found that the synergistic effect exits in different layers of catalyst surfaces. The calculated results show that the layer-substituted Pd atoms on the surface of Cu catalysts exhibit a better catalytic activity for NH3 dehydrogenation compared to the clean Cu (1 1 1) surface.

  6. Facile preparation of ZIF-8@Pd-CSS sandwich-type microspheres via in situ growth of ZIF-8 shells over Pd-loaded colloidal carbon spheres with aggregation-resistant and leach-proof properties for the Pd nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Tong; Lin, Lu [State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian, 116024 (China); Zhang, Xiongfu, E-mail: xfzhang@dlut.edu.cn [State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian, 116024 (China); Liu, Haiou; Yan, Xinjuan [State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian, 116024 (China); Liu, Zhang; Yeung, King Lun [Department of Chemical and Biomolecular Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR (China)

    2015-10-01

    Graphical abstract: - Highlights: • Uniform-sized colloidal carbon spheres were synthesized from low-cost glucose. • Pd nanoparticles were loaded onto the carbon spheres via self-reduction method. • A layer of ZIF-8 shell was in situ grown over the Pd-loaded carbon spheres. • The ZIF-8@Pd-CCS showed leach-proof and aggregation-resistant properties of Pd. - Abstract: Aiming to enhance the stability of noble metal nanoparticles that are anchored on the surface of colloidal carbon spheres (CCSs), we designed and prepared a new kind of sandwich-structured ZIF-8@Pd-CCS microsphere. Typically, uniform CCSs were first synthesized by the aromatization and carbonization of glucose under hydrothermal conditions. Subsequently, noble metal nanoparticles, herein Pd nanoparticles, were attached to the surface of CCSs via self-reduction route, followed by in situ assembly of a thin layer of ZIF-8 over the Pd nanoparticles to form the sandwich-type ZIF-8@Pd-CCS microspheres. X-ray diffraction (XRD) patterns and Fourier transform infrared spectroscopy (FTIR) spectra confirmed the presence of crystalline ZIF-8, while TEM analysis revealed that the ZIF-8 shells were closely bound to the Pd-loaded CCSs. The shell thickness could be tuned by varying the ZIF-8 assembly cycles. Further, liquid-phase hydrogenation of 1-hexene as the probe reaction was carried out over the ZIF-8@Pd-CCS microspheres and results showed that the prepared microspheres exhibited excellent agglomeration-resistant and leach-proof properties for the Pd nanoparticles, thus leading to the good reusability of the ZIF-8@Pd-CCS microspheres.

  7. Advances of PD-1/PD-L1 Signaling Pathway in Immune Escape and Treatment for 
Non-small Cell Lung Cancer

    Directory of Open Access Journals (Sweden)

    Cheng LIN

    2014-10-01

    Full Text Available Lung cancer is the leading cause of cancer-related mortality worldwide. Despiting the great progress on target agents, majority of people who do not harbor a mutation could not get benefit from them. Immunotherapy, through stimulating the body's immune system to improve the antitumor immunity effect, has been a new therapeutic method for non-small cell lung cancer (NSCLC. Study had been reported that immune checkpoint molecules, including programmed death-1 (PD-1/PD-ligand (L 1 axis, are closedly related with cancer generation and development, and play a key role on clinical significance of NSCLC. Activation of PD-1/PD-L1 pathway contributes to tumor immune escape, and block PD-1/PD-L1 pathway can enhance endogenous antimuor immunity. Currently increasing clinical trials suggested that immune checkpoint inhibitors, including anti-PD-1 and anti-PD-L1 monoclonal antibodies turned out to be beneficial and safe in NSCLC. Here, we provide a review on the progress of PD-1/PD-L1 pathway and immune checkpoint inhibitors in NSCLC.

  8. Evidence for a role of the PD-1:PD-L1 pathway in immune resistance of HPV-associated head and neck squamous cell carcinoma

    Science.gov (United States)

    Lyford-Pike, Sofia; Peng, Shiwen; Young, Geoffrey D.; Taube, Janis M.; Westra, William H.; Akpeng, Belinda; Bruno, Tullia C.; Richmon, Jeremy D.; Wang, Hao; Bishop, Justin A.; Chen, Lieping; Drake, Charles G.; Topalian, Suzanne L.; Pardoll, Drew M.; Pai, Sara I.

    2013-01-01

    Human papillomavirus-associated head and neck squamous cell carcinomas (HPV-HNSCC) originate in the tonsils, the major lymphoid organ that orchestrates immunity to oral infections. Despite its location, the virus escapes immune elimination during malignant transformation and progression. Here, we provide evidence for the role of the PD-1:PD-L1 pathway in HPV-HNSCC immune resistance. We demonstrate membranous expression of PD-L1 in the tonsillar crypts, the site of initial HPV infection. In HPV-HNSCCs that are highly infiltrated with lymphocytes, PD-L1 expression on both tumor cells and CD68+ tumor associated macrophages (TAMs) is geographically localized to sites of lymphocyte fronts, while the majority of CD8+ tumor infiltrating lymphocytes (TILs) express high levels of PD-1, the inhibitory PD-L1 receptor. Significant levels of mRNA for interferon-γ (IFN-γ), a major cytokine inducer of PD-L1 expression, were found in HPV+ PD-L1(+) tumors. Our findings support the role of the PD-1:PD-L1 interaction in creating an “immune-privileged” site for initial viral infection and subsequent adaptive immune resistance once tumors are established and suggest a rationale for therapeutic blockade of this pathway in patients with HPV-HNSCC. PMID:23288508

  9. The PD-1/PD-L1 inhibitory pathway is altered in pre-eclampsia and regulates T cell responses in pre-eclamptic rats.

    Science.gov (United States)

    Tian, Mei; Zhang, Yonghong; Liu, Zhaozhao; Sun, Guoqiang; Mor, Gil; Liao, Aihua

    2016-01-01

    The programmed cell death-1(PD-1)/PD-ligand 1 (PD-L1) pathway is critical to immune homeostasis by promoting regulatory T (Treg) development and inhibiting effector T (such as Th17) cell responses. However, the association between the PD-1/PD-L1 pathway and the Treg/Th17 imbalance has not been fully investigated in pre-eclampsia (PE). In this study, we observed an inverse correlation between the percentages of Treg and Th17 cells, and the expression of PD-1 and PD-L1 on the two subsets also changed in PE compared with normal pregnancy. We further explored their relationship in vivo using the L-NG-Nitroarginine Methyl Ester (L-NAME) induced PE-like rat models, also characterized by Treg/Th17 imbalance. Administration of PD-L1-Fc protein provides a protective effects on the pre-eclamptic models, both to the mother and the fetuses, by reversing Treg/Th17 imbalance through inhibiting PI3K/AKT/m-TOR signaling and enhancing PTEN expression. In addition, we also observed a protective effect of PD-L1-Fc on the placenta by reversing placental damages. These results suggested that altered PD-1/PD-L1 pathway contributed to Treg/Th17 imbalance in PE. Treatment with PD-L1-Fc posed protective effects on pre-eclamptic models, indicating that the use of PD-L1-Fc might be a potential therapeutic target in PE treatment. PMID:27277012

  10. Selective Hydrogenation of Acetylene over Pd, Au, and PdAu Supported Nanoparticles

    Science.gov (United States)

    Walker, Michael P.

    The removal of trace amounts of acetylene in ethylene streams is a high-volume industrial process that must possess high selectivity of alkyne hydrogenation over hydrogenation of alkenes. Current technology uses metallic nanoparticles, typically palladium or platinum, for acetylene removal. However, problems arise due to the deactivation of the catalysts at high temperatures as well as low selectivities at high conversions. Pore expanded MCM-41 is synthesized via a two-step strategy in which MCM-41 was prepared via cetyltrimethylammonium bromide (CTMABr) followed by the hydrothermal treatment with N,N-dimethyldecylamine (DMDA). This material was washed with ethanol to remove DMDA, or calcined to remove both surfactants. PE-MCM-41 based materials were impregnated with palladium, gold, and palladium-gold nanoparticles. The removal of DMDA had an effect on both the conversion and selectivity, in which they were found to drop significantly. However, by using the bimetallic PdAu catalysts, higher selectivity could be achieved due to increased electron density.

  11. 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.

  12. 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.

  13. 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).

  14. Potential of ZrO clusters as replacement Pd catalyst

    Science.gov (United States)

    Behera, Swayamprabha; King, Nicholas; Samanta, Devleena; Jena, Puru

    2014-07-01

    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 Pdn and (ZrO)n clusters (n = 1-5). We further studied the reaction of these clusters in neutral and charged forms with H2, O2, 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.

  15. 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.

  16. 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

  17. Study of evaporation processes in Dy - Pd system

    Energy Technology Data Exchange (ETDEWEB)

    Zajtsev, A.I.; Priselkov, Yu.A.; Nesmeyanov, A.N. (Moskovskij Gosudarstvennyj Univ. (USSR))

    Disprosium and palladium vapor pressure above Dy-Pd alloys in the 0-80 at.% concentration range is measured using the integral variant of the Knudsen effusive method in ultrahigh oilless vacuum. Temperature dependences of vapor pressure are calculated along with partial and integral thermodynamic functions according to the data obtained. The results are in a good agreement with the system constitution diagram.

  18. 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

  19. Precipitation hardening of biodegradable Fe-Mn-Pd alloys

    International Nuclear Information System (INIS)

    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 {1 0 0} 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.

  20. Hysteresis-free nanoplasmonic pd-au alloy hydrogen sensors

    DEFF Research Database (Denmark)

    Wadell, Carl; Nugroho, Ferry Anggoro Ardy; Lidström, Emil;

    2015-01-01

    The recent market introduction of hydrogen fuel cell cars and the prospect of a hydrogen economy have drastically accelerated the need for safe and accurate detection of hydrogen. In this Letter, we investigate the use of arrays of nanofabricated Pd-Au alloy nanoparticles as plasmonic optical...

  1. 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...

  2. Magnetic properties of the orthorhombic NdPd

    Science.gov (United States)

    Dhar, Vijay; Provino, A.

    2016-09-01

    The equiatomic NdPd compound crystallizes in the orthorhombic CrB structure type (oS8, Cmcm, No. 63). The NdPd phase melts congruently at 1240 °C, as observed by differential thermal analysis; one further sharp thermal effect detected at 1040 °C is very likely due to a structural transition. We confirm the CrB prototype for the low-temperature form of NdPd. The lattice parameters of this compound are a=3.842(2) Å, b=10.776(7) Å, c=4.605(2) Å, as obtained from Guinier powder pattern; those for the corresponding iso-structural LaPd compound, prepared as non-magnetic reference, are a=3.947(2) Å, b=11.036(3) Å, c=4.663(2) Å. Despite the fact that NdPd has been known since long, its physical properties have not been investigated till date. Here we report the results of magnetization, heat capacity and electrical resistivity measurements performed on this compound. NdPd undergoes a single ferromagnetic transition close to 15 K, inferred from a sharp upturn in the magnetization at lower temperatures and from Arrott plots measured at selected temperatures between 1.9 and 18 K. The coercive field and remnant magnetization at 1.9 K are 320 Oe and 0.24 μB/f.u., which become negligible at 15 K. A sharp peak in the heat capacity at ≈15 K confirms the bulk magnetic transition. Isothermal magnetization at 2 K shows a tendency to saturation, reaching a value of 1.9 μB/f.u. at the maximum applied field of 70 kOe. The zero field resistivity shows an anomaly near 15 K, in correspondence with the magnetic and heat capacity data. A negative magnetoresistivity, typical of a ferromagnet, is observed in the magnetically ordered state in an applied magnetic field of 50 kOe. LaPd is a typical Pauli paramagnet with a Sommerfeld coefficient γ=3.9 mJ/mol K2.

  3. One-step facile synthesis of Pd nanoclusters supported on carbon and their electrochemical property

    OpenAIRE

    Junjun Shi; Xiulan Hu; Jianbo Zhang; Weiping Tang; Hongtao Li; Xiaodong Shen; Nagahiro Saito

    2014-01-01

    Well-crystallized Pd nanoclusters supported on Ketjen Black (KB) were successfully fabricated when Pd wires were served as an electrode pair by a solution plasma technique at atmospheric pressure. The synthesis of Pd nanoclusters was almost simultaneous with their dispersion on KB. Pd nanoclusters with the average diameter of about 2 nm were equably distributed on KB, and showed good electrochemical property corresponding to their obvious characteristic peaks. Multi-scan cyclic voltammetry an...

  4. Tungsten carbide promoted Pd and Pd–Co electrocatalysts for formic acid electrooxidation

    DEFF Research Database (Denmark)

    Yin, Min; Li, Qingfeng; Jensen, Jens Oluf;

    2012-01-01

    Tungsten carbide (WC) promoted palladium (Pd) and palladium–cobalt (Pd–Co) nanocatalysts are prepared and characterized for formic acid electrooxidation. The WC as the dopant to carbon supports is found to enhance the CO tolerance and promote the activity of the Pd-based catalysts for formic acid...... oxidation. Alloying of Pd with Co further improves the electrocatalytic activity and stability of the WC supported catalysts, attributable to a synergistic effect of the carbide support and PdCo alloy nanoparticles....

  5. RuPd, RuCo, PdCo and RuPdCo materials as candidates for cathode catalyzers in PEM fuel cells; Materiales RuPd, RuCo, PdCo y RuPdCo como candidatos a catalizadores catodicos en celdas de combustible tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Leyva Noyola, Fatima; Solorza Feria, Omar [Centro de Investigacion y Estudios Superiores del IPN, Mexico, D.F. (Mexico)]. E-mail: fleyva@cinvestav.mx

    2009-09-15

    This work reports on the catalytic activity of RuPd, RuCo, PdCo and RuPdCo material for oxygen reduction reaction (ORR). These materials were synthesized using chemical reduction with NaBH{sub 4} as a reducing agent in THF, in ambient temperature and pressure conditions. The evaluation of the catalytic activity was done using cyclic voltamperometry (CV) and rotary disc electrode (RDE) in H{sub 2}SO{sub 4} 0.5 M. The kinetic results showed that the electrochemical reaction involves 4 electrons and the transfer of the first electron is the determinant stage. The values of {alpha}, i0 and the Tafel slope were very similar for the four materials studied, around 0.4, 5x10{sup -6} mA cm{sup -2} and 60 mV dec-1, respectively. Although these values are less than those reported for nanostructured platinum, they are better than those reported for other materials such as pure Pd, which enables them to be considered as cathode catalysts for a proton exchange membrane fuel cell. [Spanish] En este trabajo se reporta la actividad catalitica de los materiales RuPd, RuCo, PdCo y RuPdCo para la reaccion de reduccion de oxigeno (RRO). Estos materiales fueron sintetizados por el metodo de reduccion quimica, usando NaBH{sub 4} como agente reductor en THF, en condiciones de temperatura y presion ambiental. La evaluacion de la actividad catalitica fue realizada usando Voltamperometria Ciclica (VC) y Electrodo Disco Rotatorio (EDR) en H{sub 2}SO{sub 4} 0.5 M. Los resultados cineticos mostraron que la reaccion electroquimica procede por la via de 4 electrones y la etapa determinante es la transferencia del primer electron. Los valores de {alpha}, i0 y pendiente de Tafel fueron muy similares para los 4 materiales estudiados, siendo estos de alrededor de 0.4, 5x10{sup -6} mA cm{sup -2} y 60 mV dec{sup -1}, respectivamente. Sin embargo, aun cuando estos valores son menores que los reportados para platino nanoestructurado, son mejores que los reportados para otros materiales como el Pd puro

  6. Ultra-Fast Synthesis for Ag2Se and CuAgSe Thermoelectric Materials

    Science.gov (United States)

    DUAN, H. Z.; LI, Y. L.; ZHAO, K. P.; QIU, P. F.; SHI, X.; CHEN, L. D.

    2016-10-01

    Ag2Se and CuAgSe have been recently reported as promising thermoelectric materials at room temperature. The traditional melting-annealing-sintering processes are used to grow Ag2Se and CuAgSe materials with the disadvantages of high costs of energy and time. In this work, phase-pure polycrystalline Ag2Se and CuAgSe compounds were synthesized from raw elemental powders directly by manual mixing followed by spark plasma sintering (MM-SPS) in a few minutes. The influence of SPS heating rate on the phase composition, microstructure, and thermoelectric properties, including Seebeck coefficient, electrical conductivity, and thermal conductivity, were investigated. The zTs of 0.8 at 390 K and 0.6 at 450 K are obtained for Ag2Se and CuAgSe, respectively, which is comparable with the values in the materials prepared by the traditional method. Furthermore, this ultrafast sample synthesis can significantly save material synthesis time and thus has the obvious advantage for large-scale production.

  7. Observation of a Ag protrusion on a Ag2S island using a scanning tunneling microscope

    Directory of Open Access Journals (Sweden)

    Takeo Ohno

    2015-01-01

    Full Text Available A silver sulfide (Ag2S island as an ionic conductor in resistive switching memories was formed and a protrusion of silver from the Ag2S formed by an electrochemical reaction was observed using a scanning tunneling microscope.

  8. Charge-transfer interactions between TCNQ and silver clusters Ag20 and Ag13.

    Science.gov (United States)

    Chen, Jing; Zhang, Hanyu; Liu, Xianhu; Yuan, Chengqian; Jia, Meiye; Luo, Zhixun; Yao, Jiannian

    2016-03-14

    Interactions between tetracyanoquinodimethane (TCNQ) and two typical silver clusters Ag13 and Ag20 are studied by first-principles DFT calculations. Charge transfer (CT) from silver clusters to TCNQ molecules initiates the Ag-N bond formation at selective sites resulting in the formation of different isomers of Ag13-TCNQ and Ag20-TCNQ complexes. We show here a comprehensive spectroscopic analysis for the two CT complexes on the basis of Raman and infrared activities. Furthermore, frontier molecular orbital (FMO) and natural bond orbital (NBO) analysis of the complexes provides a vivid illustration of electron cloud overlap and interactions. The behavior of TCNQ adsorbed on the tetrahedral Ag20 cluster was even found in good agreement with the experimental measurement of TCNQ molecules on a single-crystal Ag(111) surface. This study not only endeavors to clarify the charge-transfer interactions of TCNQ with silver, but also presents a finding of enhanced charge transfer between Ag13 and TCNQ indicating potential for candidate building blocks of granular materials. PMID:26888771

  9. Properties of Ag/AgCl electrodes fabricated with IC-compatible technologies

    NARCIS (Netherlands)

    Bousse, L.J.; Bergveld, P.; Geeraedts, H.J.M.

    1986-01-01

    The purpose of this work is to fabricate and characterize Ag/AgCl electrodes made on a silicon chip at the wafer level with integrated circuit-compatible fabrication techniques. Such electrodes are useful as reference electrodes in several kinds of chemical sensors. Two types of electrode were inves

  10. Radiation hardness of LuAG:Ce and LuAG:Pr scintillator crystals

    CERN Document Server

    Derdzyan, M V; Belsky, A; Dujardin, C; Lecoq, P; Lucchini, M; Ovanesyan, K L; Pauwels, K; Pedrini, C; Petrosyan, A G

    2012-01-01

    Single crystals of LuAG:Ce, LuAG:Pr and un-doped LuAG were grown by the vertical Bridgman method and studied for radiation hardness under gamma-rays with doses in the range 10-10(5) Gy (Co-60). A wide absorption band peaking at around 600 nm springs up in all three types of crystals after the irradiations. The second band peaking at around 375 nm appears in both LuAG:Pr and un-doped LuAG. Compositional variations have been done to reveal the spectral behavior of induced color centers in more detail and to understand their origin. Similarities in behavior of Yb2+ centers in as-grown garnets are found, indicating that radiation induced color centers can be associated with residual trace amounts of Yb present in the raw materials. Un-doped LuAG and LuAG:Ce demonstrate moderate radiation hardness (the induced absorption coefficients being equal to 0.05-0.08 cm(-1) for accumulated doses of 10(3)-10(4) Gy), while LuAG:Pr is less radiation hard. The ways to improve the radiation hardness are discussed.

  11. Effect of MWNT electroless Ag plating on field emission properties of MWNT/Ag nanocomposite cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Ye Yun, E-mail: yeyun07@fzu.edu.cn [College of Physics and Information Engineering, Fuzhou University, Fuzhou 350002 (China); Guo Tailiang [College of Physics and Information Engineering, Fuzhou University, Fuzhou 350002 (China)

    2013-01-01

    Highlights: Black-Right-Pointing-Pointer Ag nanoparticles and coating were electroless plated onto the surface of CNTs. Black-Right-Pointing-Pointer A low turn on field of CNT/Ag cathode was achieved. Black-Right-Pointing-Pointer A new way for high stability of CNT/Ag cathode was suggested. - Abstract: Field emission properties of multiwall carbon nanotube (MWNT) electroless Ag plating nanocomposite cathodes fabricated using screen printing were studied. The MWNT was purified and electroless plated with Ag. The results of field emission scanning electron microscopy (FESEM) showed that the morphology of Ag electroless plating on the surface of MWNT depended on the temperature of electroless plating. Experiments showed that the stability of MWNT/Ag nanocomposite cathodes had no more than 10% degradation, achieving a field emission current density of 4.0 mA/cm{sup 2} at an applied electric field of 0.5 V/{mu}m for 50 h. The proposed MWNT/Ag nanocomposite cathodes possess good field emission properties and have potential for application in field emission displays.

  12. First-principles study of surface plasmons on Ag(111) and H/Ag(111)

    DEFF Research Database (Denmark)

    Yan, Jun; Jacobsen, Karsten Wedel; Thygesen, Kristian Sommer

    2011-01-01

    Linear-response time-dependent density functional theory is used to investigate the relation between molecular bonding and surface plasmons for the model system H/Ag(111). We employ an orbital-dependent exchange-correlation functional to obtain a correct description of the Ag 3d band, which is cr...

  13. Synthesis and characterization of nanostructured Ag on porous titania

    International Nuclear Information System (INIS)

    In this work, porous titania was prepared on bulk Ti by chemical oxidation, and then nanostructured silver (Ag) was deposited on titania surface by ion beam sputtering. After annealing treatment, Ag/TiO2 composites were characterized using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results indicated that a nano-porous titania layer with mean pore size of 150 nm and thickness of 1 μm was formed by chemical oxidation at 80 deg. C for 45 min. There were three Ag species (Ag (0), Ag (1+), and Ag (2+)) on composites surface after annealing treatment, and metallic Ag content achieved maximum value with annealing temperature of 500 deg. C in air. Ag showed high thermal stability being partly attributed to the inhibiting the diffusion of Ag by the underlying porous titania.

  14. Ag on Si(111) from basic science to application

    Energy Technology Data Exchange (ETDEWEB)

    Belianinov, Aleksey [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    In our work we revisit Ag and Au adsorbates on Si(111)-7x7, as well as experiment with a ternary system of Pentacene, Ag and Si(111). Of particular interest to us is the Si(111)-(√3x√3)R30°}–Ag (Ag-Si-√3 hereafter). In this thesis I systematically explore effects of Ag deposition on the Ag-Si-√3 at different temperatures, film thicknesses and deposition fluxes. The generated insight of the Ag system on the Si(111) is then applied to generate novel methods of nanostructuring and nanowire growth. I then extend our expertise to the Au system on the Ag-Si(111) to gain insight into Au-Si eutectic silicide formation. Finally we explore behavior and growth modes of an organic molecule on the Ag-Si interface.

  15. Growth of CuPd nanoalloys encapsulated in carbon-shell

    Energy Technology Data Exchange (ETDEWEB)

    Kang, H. Y.; Wang, H. P., E-mail: wanghp@mail.ncku.edu.tw [National Cheng Kung University, Department of Environmental Engineering (China)

    2013-05-15

    Preparation of nanostructured copper-palladium (CuPd) alloys is getting more attention because specific catalytic properties can be tuned by controlling their composition, size, and shape. Thus, a better understanding especially in the formation mechanism of the CuPd nanoalloys is of great importance in designing the catalysts. Growth of CuPd nanoalloys encapsulated in carbon-shell (CuPd-C) was, therefore, studied by in situ synchrotron small-angle X-ray scattering during temperature-programed carbonization (TPC) of the Cu{sup 2+}- and Pd{sup 2+}-{beta}-cyclodextrin complexes. A rapid reduction of Cu{sup 2+} and Pd{sup 2+} with nucleation is found at the temperatures of <423 K, followed by coalescence at 453-573 K. The well-dispersed CuPd nanoalloys having the sizes of 7.6-7.9 nm in diameter are encapsulated in carbon-shell of 1.4-1.8 nm in thickness. The refined extended X-ray absorption fine structure spectra indicate that the bond distances of the first-shell Cu-Pd are 2.61-2.64 A with the coordination numbers of 5.1-5.6. A homogeneous CuPd alloy at the Cu/Pd atomic ratio of 1 is observed. Note that at the high Cu/Pd ratio, Cu is enriched on the CuPd nanoalloy surfaces, attributable to the relatively low surface free energy of Cu.

  16. Spontaneous dispersion of PdO onto acid sites of zeolites studied by in situ DXAFS

    International Nuclear Information System (INIS)

    The generation of highly dispersed PdO over zeolite supports was studied using in situ energy-dispersive XAFS (DXAFS) technique. From the comparison with the Na-ZSM-5, it was found that the oxidation as well as the spontaneous dispersion of Pd was promoted through the interaction between PdO and acid sites of H-form zeolites. (author)

  17. Refolding and Characterization of Recombinant Human GST-PD-1 Fusion Protein Expressed in Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    Da-Wei LI; Jian-Feng YU; Yong-Jing CHEN; Hong-Bing MA; Zheng-Fei WANG; Yi-Bei ZHU; Xue-Guang ZHANG

    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-5x-3. The fusion protein GST-PD-1 was effectivelyexpressed in E. coli BL21 (DE3) as inclusion bodies and a denaturation and refolding procedure was performed to obtain bioactive soluble GST-PD-1. Fusion protein of above 95% purity was acquired by a convenient 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 GSTPD-1 could competently block the interaction between PD-L1 and PD-1 and increase the production of IL2 and IFN-γ of phytohemagglutinin-activated T cells.

  18. PD-1 suppresses protective immunity to Streptococcus pneumoniae through a B cell-intrinsic mechanism

    Science.gov (United States)

    McKay, Jerome T.; Egan, Ryan P.; Yammani, Rama D.; Chen, Lieping; Shin, Tahiro; Yagita, Hideo; Haas, Karen M.

    2015-01-01

    Despite the emergence of the PD-1:PD-1 ligand (PD-L) regulatory axis as a promising target for treating multiple human diseases, remarkably little is known about how this pathway regulates responses to extracellular bacterial infections. We found that PD-1−/− mice, as well as wild type mice treated with a PD-1 blocking antibody, exhibited significantly increased survival against lethal Streptococcus pneumoniae infection following either priming with low-dose pneumococcal respiratory infection or S. pneumoniae-capsular polysaccharide immunization. Enhanced survival in mice with disrupted PD-1:PD-L interactions was explained by significantly increased proliferation, isotype switching, and IgG production by pneumococcal capsule-specific B cells. Both PD-1 ligands, B7-H1 and B7-DC, contributed to PD-1-mediated suppression of protective capsule-specific IgG. Importantly, PD-1 was induced on capsule-specific B cells and suppressed IgG production and protection against pneumococcal infection in a B cell-intrinsic manner. These results provide the first demonstration of a physiologic role for B cell-intrinsic PD-1 expression in vivo. In summary, our study reveals that B cell-expressed PD-1 plays a central role in regulating protection against S. pneumoniae, and thereby represents a promising target for bolstering immunity to encapsulated bacteria. PMID:25624454

  19. Electrodeposition of PdCu alloy and its application in methanol electro-oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Ming-Wei [Department of Chemistry, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Whang, Thou-Jen, E-mail: twhang@mail.ncku.edu.tw [Department of Chemistry, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China)

    2013-04-01

    This study demonstrates a simple electrodeposition method to fabricate the palladium–copper alloy on an ITO coated glass (PdCu/ITO) and its application in methanol electro-oxidation. Our approaches involve the co-reduction of Pd and Cu using triethanolamine (TEA) as a complexing agent in the electroplating bath and a Pd redox replacement of Cu on the surface of the as-prepared PdCu alloy. The phase structures, alloy compositions and morphologies of catalysts are determined by X-ray diffraction, energy dispersive spectrometer and scanning electron microscopy, respectively. X-ray diffraction shows that the particle size of PdCu deposits shrink when the alloy is deposited in a TEA-contained solution. The electrocatalytic properties of PdCu alloys and Pd redox replacement modified PdCu alloys for methanol oxidation have been investigated by cyclic voltammetry. The PdCu alloy with atomic ratio of 20.5% Cu exhibits higher catalytic activity toward methanol oxidation compared with a pure Pd catalyst. PdCu alloys with smaller particle sizes associated with TEA agent and the surface confined Pd replacement are found to have enhanced catalytic performance in the electro-oxidation of methanol.

  20. Evaluation of neutron cross sections for the Pd isotopes (RCN-3 data library)

    International Nuclear Information System (INIS)

    The evaluation procedure to obtain neutron cross sections of 102Pd, 104Pd, 105Pd, 106Pd, 107Pd, 108Pd and 110Pd for inclusion in the RCN-3 data library of fission-product cross sections is described. The new evaluation takes into account the results of recent differential and integral data. Most of the adopted resolved resonance parameters have been taken from the new CBNM measurements; for 107Pd the recent RPI data have been used. These resolved resonance parameters have been extensively analysed to obtain average values for the level spacing, capture width and neutron s- and p-wave strength functions. The systematics of the single-particle level-density parameter α and the capture width show significant odd-even effects. Optical-model and statistical-model calculations have been performed to obtain cross sections of reactions at energies from 1 meV to 15 MeV. The results for the capture cross sections based upon the analysed average resonance parameters turned out to be systematically lower than the ORELA average capture data and also lower than indicated by the most integral STEK data (except for 105Pd). As a compromise we have performed adjustments to increase the calculated fast capture cross sections for 104Pd, 106Pd and 108Pd