WorldWideScience

Sample records for au br cu

  1. Novel CX⋯π halogen bonds in complexes of acetylene and its derivatives of Na and MPH3 (M=Cu, Ag, Au) with XCCF (X=Cl, Br, I).

    Science.gov (United States)

    Zhuo, Hongying; Liu, Mingjuan; Li, Qingzhong; Li, Wenzuo; Cheng, Jianbo

    2014-06-05

    Ab initio calculations have been carried out for a variety of model systems with a T-shaped CX⋯π motif. The CX⋯π interaction of acetylene with the halogen donor molecule XCCF (X=Cl, Br, I) is invariably found to be weak with the interaction energy less than 11kJ/mol in magnitude. Substitution of the two protons in acetylene with more electron-donating sodium atoms increases the π electron density in the CC bond and leads to a substantial enhancement in its interaction with the halogen donor. The calculated interaction energies increase to as much as 73kJ/mol in the case of C2Na2-ICCF. The interaction of XCCF with a model coinage metal ethynide, H3PMCCMPH3 (M=Cu, Ag, Au), is intermediate between these two extremes, and the interaction energy is related to the nature of coinage metals. The CX⋯π halogen bonds have been analyzed with natural bond orbital, atoms in molecules, and energy decomposition. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Surface structure of AU3Cu(001)

    DEFF Research Database (Denmark)

    Eckstein, G.A.; Maupai, S.; Dakkouri, A.S.

    1999-01-01

    The surface morphology, composition, and structure of Au3Cu(001) as determined by scanning tunneling microscopy and surface x-ray diffraction are presented. Atomic resolution STM images reveal distinctive geometric features. The analysis of the surface x-ray diffraction data provides clear evidence...... for the surface structure. [S0163-1829(99)04535-X]....

  3. In-situ STM study of phosphate adsorption on Cu(111), Au(111) and Cu/Au(111) electrodes

    DEFF Research Database (Denmark)

    Schlaup, Christian; Horch, Sebastian

    2013-01-01

    The interaction of Cu(111), Au(111) and Cu-covered Au(111) electrodes with a neutral phosphate buffer solution has been studied by means of cyclic voltammetry (CV) and in situ electrochemical scanning tunneling microscopy (EC-STM). Under low potential conditions, both the Cu(111) and the Au(111) ...

  4. High-temperature stability of Au/Pd/Cu and Au/Pd(P)/Cu surface finishes

    Science.gov (United States)

    Ho, C. E.; Hsieh, W. Z.; Lee, P. T.; Huang, Y. H.; Kuo, T. T.

    2018-03-01

    Thermal reliability of Au/Pd/Cu and Au/Pd(4-6 wt.% P)/Cu trilayers in the isothermal annealing at 180 °C were investigated by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and transmission electron microscopy (TEM). The pure Pd film possessed a nanocrystalline structure with numerous grain boundaries, thereby facilitating the interdiffusion between Au and Cu. Out-diffusion of Cu through Pd and Au grain boundaries yielded a significant amount of Cu oxides (CuO and Cu2O) over the Au surface and gave rise to void formation in the Cu film. By contrast, the Pd(P) film was amorphous and served as a good diffusion barrier against Cu diffusion. The results of this study indicated that amorphous Pd(P) possessed better oxidation resistance and thermal reliability than crystalline Pd.

  5. High-speed CuBr brightness amplifier beam profile

    Science.gov (United States)

    Evtushenko, G. S.; Torgaev, S. N.; Trigub, M. V.; Shiyanov, D. V.; Evtushenko, T. G.; Kulagin, A. E.

    2017-01-01

    This paper addresses the experimental study of the beam profile of the CuBr brightness amplifier operating at a wide range of pulse repetition frequencies. The use of a medium-size gas discharge tube (2 cm) ensures the operation of the brightness amplifier both at typical PRFs (520 kHz) and at higher PRFs (up to 100 kHz), either with or without HBr additive. The effect of the active additive on the beam profile is demonstrated. The testing results on kinetic modeling of radial processes in the laser (brightness amplifier) plasma are also discussed.

  6. Fuzzy analytical hierarchy process and GIS for predictive cu -au ...

    African Journals Online (AJOL)

    In the Mokhtaran sheet for predictive Cu -Au porphyry this method was used. Combining this way with geographic information systems GIS is effective approach for predictive Mineral prospectively mapping (MPM) for Cu -Au porphyry. For preparing MPM, the criteria were geological data (host rocks, heat rocks, alteration), ...

  7. Magnetoelectric effects in the spiral magnets CuCl2 and CuBr2.

    Science.gov (United States)

    Tolédano, P; Ayala, A P; Furtado Filho, A F G; do Nascimento, J P C; Silva, M A S; Sombra, A S B

    2017-01-25

    The nature and symmetry of transition mechanisms in the spin-spiral copper halides CuCl2 and CuBr2 are analyzed theoretically. The magnetoelectric effects observed in the two multiferroic compounds are described and their phase diagram at zero and applied magnetic fields are worked out. The emergence of the electric polarization at zero field below the paramagnetic phase is shown to result from the coupling of two distinct spin-density waves and to be only partly related to the Dzialoshinskii-Moriya interactions. Applying a magnetic field along the two-fold monoclinic axis of CuCl2 yields a decoupling of the spin-density waves modifying the symmetry of the phase and the spin-spiral orientation. The remarkable periodic dependences of the magnetic susceptibility and polarization, on rotating the field in the monoclinic plane, are described theoretically.

  8. Bovins et humains au Brésil en 2007

    Directory of Open Access Journals (Sweden)

    Hervé Théry

    2008-03-01

    Full Text Available On recherche 35 millions de bovins… Selon les données récemment publiées par l’IBGE (Censo Agropecuário 2006, Resultados preliminares le Brésil comptait en 2006 un peu moins de 170 millions de têtes de bétail, alors que selon la Pesquisa Pecuária Municipal, du même IBGE et à la même date, le pays en comptait alors près de 206 millions.Sans chercher pour le moment la cause de cette différence – de méthodologie, très probablement – et en se rappelant que l’IBGE avertit que ces données provisoi...

  9. Study on Oxidation of Cu and Cu3Au Surfaces with Hyperthermal Oxygen Molecular Beam

    Science.gov (United States)

    Okada, Michio; Teraoka, Yuden

    Corrosion wastes more than a few percent of the world's GDP every year. The initial stage of the corrosion is one of the central topics in material science. The oxidation is one of the major corrosion processes of metals. Thus, the study of the oxidation process on metal surfaces is generally interesting in various fields of science and technology. The growth of a protective thin surface layer, which prevents further oxidation into bulk of a metal, requires the formation of a homogeneous film. One simple way for the protection of underlying metals is surface alloying, combining different substances to form multi-component surfaces. The surface alloying leads to the formation of a protective oxide layer due to the preferential oxidation of one component, possibly with surface segregation. Copper and copper alloys have wide industrial applications, and therefore are of interest for studies of oxidation mechanism, especially in the Cu2O formation. Cu forms the stable Cu2O, while Au does not form a stable oxide and is not soluble into stable Cu2O. Thus, the Cu-Au alloy system is ideal for investigating the effect of alloying on the formation of protective layer against further oxidation into bulk. Here, we introduce our recent comparative studies of the oxidation of Cu(100) and Cu3Au(100) with hyperthermal O2 molecular beam and discuss why Cu3Au(100) is protective against the oxidation.

  10. PHENIX results on flow observables in asymmetric Cu + Au collisions

    Science.gov (United States)

    Schaefer, B.

    2016-12-01

    Measurements of anisotropic flow from Cu+Au √{sNN} = 200 GeV collisions in PHENIX at RHIC in 2012 are presented for inclusive charged particles and identified hadrons π±, K±, p, and p ‾ at midrapidity. Fourier coefficients characterizing the azimuthal distribution of produced particles with respect to the event plane measured at forward rapidity are examined over a broad range of pT and collision centrality. Directed, elliptic, and triangular moments (v1, v2, v3 as functions of pT) all exhibit mass ordering. Comparisons are made to Cu+Cu and Au+Au systems as well as to hydrodynamical and transport model calculations [A. Adare, et al., "Measurements of directed, elliptic, and triangular flow in Cu+Au collisions at √{sNN} = 200 GeV", arXiv:1509.07784.]. Unlike v2 and v3, v1 decreases with centrality, mass ordering is seen for all three, and v2 and v3 with respect to transverse momentum feature common scaling with 1 / (εnNpart1/3).

  11. Magnetism of CuX2 frustrated chains (X = F, Cl, Br): Role of covalency

    Science.gov (United States)

    Lebernegg, S.; Schmitt, M.; Tsirlin, A. A.; Janson, O.; Rosner, H.

    2013-04-01

    Periodic and cluster density functional theory (DFT) calculations, including DFT+U and hybrid functionals, are applied to study magnetostructural correlations in spin-(1)/(2) frustrated chain compounds CuX2: CuCl2, CuBr2, and a fictitious chain structure of CuF2. The nearest-neighbor and second-neighbor exchange integrals J1 and J2 are evaluated as a function of the Cu-X-Cu bridging angle θ in the physically relevant range 80∘-110∘. In the ionic CuF2, J1 is ferromagnetic for θ≤100∘. For larger angles, the antiferromagnetic superexchange contribution becomes dominant, in accord with the Goodenough-Kanamori-Anderson rules. However, both CuCl2 and CuBr2 feature ferromagnetic J1 in the whole angular range studied. This surprising behavior is ascribed to the increased covalency in the Cl and Br compounds, which amplifies the contribution from Hund's exchange on the ligand atoms and renders J1 ferromagnetic. At the same time, the larger spatial extent of X orbitals enhances the antiferromagnetic J2, which is realized via the long-range Cu-X-X-Cu paths. Both periodic and cluster approaches supply a consistent description of the magnetic behavior which is in good agreement with the experimental data for CuCl2 and CuBr2. Thus, owing to their simplicity, cluster calculations have excellent potential to study magnetic correlations in more involved spin lattices, and facilitate application of quantum-chemical methods.

  12. Modeling of Output Characteristics of a UV Cu+ Ne-CuBr Laser

    Directory of Open Access Journals (Sweden)

    Snezhana Georgieva Gocheva-Ilieva

    2012-01-01

    Full Text Available This paper examines experiment data for a Ne-CuBr UV copper ion laser excited by longitudinal pulsed discharge emitting in multiline regime. The flexible multivariate adaptive regression splines (MARSs method has been used to develop nonparametric regression models describing the laser output power and service life of the devices. The models have been constructed as explicit functions of 9 basic input laser characteristics. The obtained models account for local nonlinearities of the relationships within the various multivariate subregions. The built best MARS models account for over 98% of data. The models are used to estimate the investigated output laser characteristics of existing UV lasers. The capabilities for using the models in predicting existing and future experiments have been demonstrated. Specific analyses have been presented comparing the models with actual experiments. The obtained results are applicable for guiding and planning the engineering experiment. The modeling methodology can be applied for a wide range of similar lasers and laser devices.

  13. Elevated Temperature Creep Properties of Conventional 50Au-50Cu and 47Au 50Cu-3Ni Braze Alloys

    Energy Technology Data Exchange (ETDEWEB)

    STEPHENS JR.,JOHN J.; SCHMALE,DAVID T.

    2000-12-18

    The elevated temperature creep properties of the 50Au-50Cu wt% and 47Au-50Cu-3Ni braze alloys have been evaluated over the temperature range 250-850 C. At elevated temperatures, i.e., 450-850 C, both alloys were tested in the annealed condition (2 hrs. 750 C/water quenched). The minimum strain rate properties over this temperature range are well fit by the Garofalo sinh equation. At lower temperatures (250 and 350 C), power law equations were found to characterize the data for both alloys. For samples held long periods of time at 375 C (96 hrs.) and slowly cooled to room temperature, an ordering reaction was observed. For the case of the 50Au-50Cu braze alloy, the stress necessary to reach the same, strain rate increased by about 15% above the baseline data. The limited data for ordered 47Au-50Cu-3Ni alloy reflected a,smaller strength increase. However, the sluggishness of this ordering reaction in both alloys does not appear to pose a problem for braze joints cooled at reasonable rates following brazing.

  14. Energy and system size dependence of phi meson production in Cu+Cu and Au+Au collisions

    Energy Technology Data Exchange (ETDEWEB)

    STAR Coll

    2008-10-28

    We study the beam-energy and system-size dependence of {phi} meson production (using the hadronic decay mode {phi} {yields} K{sup +}K{sup -}) by comparing the new results from Cu + Cu collisions and previously reported Au + Au collisions at {radical}s{sub NN} = 62.4 and 200 GeV measured in the STAR experiment at RHIC. Data presented are from midrapidity (|y| < 0.5) for 0.4 < p{sub T} < 5 GeV/c. At a given beam energy, the transverse momentum distributions for {phi} mesons are observed to be similar in yield and shape for Cu + Cu and Au + Au colliding systems with similar average numbers of participating nucleons. The {phi} meson yields in nucleus-nucleus collisions, normalized by the average number of participating nucleons, are found to be enhanced relative to those from p + p collisions with a different trend compared to strange baryons. The enhancement for {phi} mesons is observed to be higher at {radical}s{sub NN} = 200 GeV compared to 62.4 GeV. These observations for the produced {phi}(s{bar s}) mesons clearly suggest that, at these collision energies, the source of enhancement of strange hadrons is related to the formation of a dense partonic medium in high energy nucleus-nucleus collisions and cannot be alone due to canonical suppression of their production in smaller systems.

  15. [Oxidation of mercury by CuBr2 decomposition under controlled-release membrane catalysis condition].

    Science.gov (United States)

    Hu, Lin-Gang; Qu, Zan; Yan, Nai-Qiang; Guo, Yong-Fu; Xie, Jiang-Kun; Jia, Jin-Ping

    2014-02-01

    CuBr2 in the multi-porous ceramic membrane can release Br2 at high temperature, which was employed as the oxidant for Hg0 oxidation. Hg0 oxidation efficiency was studied by a membrane catalysis device. Meanwhile, a reaction and in situ monitoring device was designed to avoid the impact of Br2 on the downstream pipe. The result showed that the MnO(x)/alpha-Al2O3 catalysis membrane had a considerable "controlled-release" effect on Br2 produced by CuBr2 decomposition. The adsorption and reaction of Hg0 and Br2 on the surface of catalysis membrane obeyed the Langmuir-Hinshelwood mechanism. The removal efficiency of Hg0 increased with the rising of Br2 concentration. However, when Br2 reached a certain concentration, the removal efficiency was limited by adsorption rate and reaction rate of Hg0 and Br2 on the catalysis membrane. From 473 K to 573 K, the variation of Hg0 oxidation efficiency was relatively stable. SO2 in flue gas inhibited the oxidation of Hg0 while NO displayed no obvious effect.

  16. Structural, electronic and mechanical properties of alloyed Au-Cu monolayer

    Science.gov (United States)

    Kapoor, Pooja; Sharma, Munish; Kumar, A.; Chandel, S. K.; Ahluwalia, P. K.

    2017-05-01

    We present a DFT based comparative study of structural, electronic and mechanical properties of Au-Cu alloyed monolayer with its pristine counterparts (Au, Cu monolayer). The value of lattice constant, binding energy and bond length of Au-Cu alloyed monolayer lies in between the values for pristine Au and Cu monolayer. An indirect band gap of 0.46 eV has been found for Au-Cu alloyed monolayer while its pristine counterparts are metallic. The band gap in alloyed Au-Cu monolayer can be further tuned with biaxial compression strain. These tunable properties of Au-Cu alloyed monolayer could have applications in nanoelectronics, sensors and nano-electromechanical systems (NEMS).

  17. Au-Ag-Cu nano-alloys: tailoring of permittivity.

    Science.gov (United States)

    Hashimoto, Yoshikazu; Seniutinas, Gediminas; Balčytis, Armandas; Juodkazis, Saulius; Nishijima, Yoshiaki

    2016-04-27

    Precious metal alloys enables new possibilities to tailor materials for specific optical functions. Here we present a systematic study of the effects of a nanoscale alloying on the permittivity of Au-Ag-Cu metals at 38 different atomic mixing ratios. The permittivity was measured and analyzed numerically by applying the Drude model. X-ray diffraction (XRD) revealed the face centered cubic lattice of the alloys. Both, optical spectra and XRD results point towards an equivalent composition-dependent electron scattering behavior. Correlation between the fundamental structural parameters of alloys and the resulting optical properties is elucidated. Plasmonic properties of the Au-Ag-Cu alloy nanoparticles were investigated by numerical simulations. Guidelines for designing plasmonic response of nano- structures and their patterns are presented from the material science perspective.

  18. Selective growth of Au nanograins on specific positions (tips, edges and facets) of Cu2O octahedrons to form Cu2O-Au hierarchical heterostructures.

    Science.gov (United States)

    Zhu, Han; Du, MingLiang; Yu, DongLiang; Wang, Yin; Zou, MeiLing; Xu, CongSheng; Fu, YaQin

    2012-12-07

    This communication demonstrates a novel strategy for the selective growth of Au nanograins (AuNGs) on specific positions (tips, edges and facets) of Cu(2)O octahedrons to form Cu(2)O-Au hierarchical heterostructures. The surface energy distribution of the octahedrons generally follows the order of γ((facets)) tips)) and leads to the preferential growth and evolution of the heterostructures. These novel Cu(2)O-Au hierarchical heterostructures show fascinating degradations of methylene blue (MB), due to the suppressed electron/hole recombination phenomena and the highly efficient light harvesting.

  19. Certification environnementale et durabilité au Brésil

    OpenAIRE

    Piketty, Marie-Gabrielle; Martins De Souza, Maria-Célia; Garcia Drigo, Isabel

    2010-01-01

    Au Brésil, les préoccupations environnementales sont croissantes du fait des impacts négatifs d’une croissance agricole accélérée sur l’environnement et les ressources naturelles. Face à ce contexte, la certification environnementale de divers produits issus de l’usage des terres agricoles et forestières augmente. Cet article analyse et compare les cas du bois issu de l’exploitation communautaire en Amazonie et du café bio. La mise en place de ces certifications est-elle à même de concilier e...

  20. Synthesis and photoluminescence properties of an unprecedented phosphinine-Cu4Br4 cluster

    NARCIS (Netherlands)

    Roesch, Philipp; Nitsch, Jörn; Lutz, Martin|info:eu-repo/dai/nl/304828971; Wiecko, Jelena; Steffen, Andreas; Müller, Christian

    2014-01-01

    A hitherto unprecedented polynuclear phosphinine-Cu(I) complex has been prepared and crystallographically characterized. The molecular structure in the crystal verifies the presence of the heterocubanetype tetrameric cluster [LCuBr]4 (L = 2,4-diphenyl-5-methyl-6-(2,3- dimethylphenyl)phosphinine),

  1. (C5H12NCu2Br3: A Piperidinium Copper(I Bromide with [Cu2Br3]− Ladders

    Directory of Open Access Journals (Sweden)

    Karl W. Krämer

    2012-10-01

    Full Text Available Piperidinium copper(I bromide, (C5H12NCu2Br3, was obtained from a solution of CuBr2, piperidine, and HBr in ethanol. At 60 °C ethanol slowly reduces copper(II to copper(I. Colorless plates of (C5H12NCu2Br3 crystallize in the triclinic space group P-1 with lattice parameters of a = 6.2948(10 Å, b = 8.2624(14 Å, c = 10.7612(17 Å, α = 75.964(19°, β = 89.232(19°, γ = 84.072(19°, and Z = 2 at 173 K. [CuBr4] tetrahedra share edges and form [Cu2Br3]− ladders parallel to the a-axis. (C5H12N+ ions adopt a chair conformation and connect the [Cu2Br3]− ladders via H-bonding. The (C5H12NCu2Br3 structure is related to the mineral rasvumite, KFe2S3, space group Cmcm, which is isostructural to several alkali copper(I halides.

  2. Comparing Ullmann Coupling on Noble Metal Surfaces: On-Surface Polymerization of 1,3,6,8-Tetrabromopyrene on Cu(111) and Au(111)

    DEFF Research Database (Denmark)

    Pham, Tuan Anh; Song, Fei; Nguyen, Manh-Thuong

    2016-01-01

    . Deposition of Br4Py on Cu(111) held at 300 K resulted in a spontaneous debromination reaction, generating the formation of a branched coordination polymer network stabilized by C−Cu−C bonds. After annealing at 473 K, the C−Cu−C bonds were converted to covalent C−C bonds, leading to the formation......The on-surface polymerization of 1,3,6,8-tetrabromopyrene (Br4Py) on Cu(111) and Au(111) surfaces under ultrahigh vacuum conditions was investigated by a combination of scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations...

  3. Surface Morphology and Electrical Resistivity in Polycrystalline Au/Cu/Si(100) System

    OpenAIRE

    Novelo, T. E.; Alonzo-Medina, G. M.; P. Amézaga-Madrid; Maldonado, R.D.

    2017-01-01

    This work describes the analysis of morphology and electrical resistivity (ρ) obtained in the Au/Cu/Si system. The Au/Cu bilayers were deposited by thermal evaporation technique with thicknesses from 50 to 250 nm on SiOx/Si(100) substrates. The Au : Cu concentration ratio of the samples was of 25 : 75 at%. The bilayers were annealed into a vacuum oven with argon atmosphere at 660 K for one hour. The crystalline structures of AuCu and CuSi alloys were confirmed by X-ray diffraction analysis. T...

  4. Enhanced catalyst activity by decorating of Au on Ag@Cu2O nanoshell

    Science.gov (United States)

    Chen, Lei; Liu, Maomao; Zhao, Yue; Kou, Qiangwei; Wang, Yaxin; Liu, Yang; Zhang, Yongjun; Yang, Jinghai; Jung, Young Mee

    2018-03-01

    We successfully synthesized Au-decorated Ag@Cu2O heterostructures via a simple galvanic replacement method. As the Au precursor concentration increased, the density of the Au nanoparticles (NPs) on the Ag@Cu2O surface increased, which changed the catalytic activity of the Ag@Cu2O-Au structure. The combination of Au, Ag, and Cu2O exhibited excellent catalytic properties, which can further effect on the catalyst activity of the Ag@Cu2O-Au structure. In addition, the proposed Ag@Cu2O-Au nanocomposite was used to transform the organic, toxic pollutant, 4-nitrophenol (4-NP), into its nontoxic and medicinally important amino derivative via a catalytic reduction to optimize the material performance. The proposed Au-decorated Ag@Cu2O exhibited excellent catalytic activity, and the catalytic reduction time greatly decreased (5 min). Thus, three novel properties of Ag@Cu2O-Au, i.e., charge redistribution and transfer, adsorption, and catalytic reduction of organic pollutants, were ascertained for water remediation. The proposed catalytic properties have potential applications for photocatalysis and localized surface plasmon resonance (LSPR)- and peroxidase-like catalysis.

  5. Charge transfer and relativistic effects in the low-lying electronic states of CuCl, CuBr and CuI

    NARCIS (Netherlands)

    Sousa, C; de Jong, W.A.; Broer, R.; Nieuwpoort, WC

    1997-01-01

    The spectral transitions and the character of the low-lying excited states of the copper halides, CuX (X = Cl, Br, I) are studied by means of two different relativistic computational approaches. One is based on the CASSCF/CASPT2 approach with operators accounting for scalar relativistic effects

  6. Study of Br, Zn, Cu and Fe concentrations in healthy and cancer breast tissues by TXRF

    Science.gov (United States)

    Magalhães, T.; Becker, M.; Carvalho, M. L.; von Bohlen, A.

    2008-12-01

    Tissue samples of fifteen breasts were analyzed by X-ray fluorescence spectrometry in order to compare the elemental concentration in healthy and carcinoma regions of the same individual. Five women were from Germany and ten from Portugal living in big cities. The elemental distribution of P, S, K, Ca, Fe, Ni, Zn, Cu and Br present in both normal and cancerous breast tissues were studied. Several contiguous thin sections (up to 10 μm thickness) of each tissue were analyzed by TXRF in order to study the homogeneity in the elemental concentration along each tissue. Correlations between elemental concentrations were established. The main goal of this study was to demonstrate the presence of Br which is assumed to play an important role in breast carcinoma development. A similar pattern for almost all the analyzed tissues was obtained: levels of P, S, K, Ca, Fe, Cu, Zn and Br increased in carcinoma tissues when compared with the corresponding healthy ones. Contrarily to the findings of this study, those of early studies showed decreased Br levels for different carcinoma tissues, unlike to most other heavy elements.

  7. Composition and source of salinity of ore-bearing fluids in Cu-Au systems of the Carajás Mineral Province, Brazil

    Science.gov (United States)

    Xavier, Roberto; Rusk, Brian; Emsbo, Poul; Monteiro, Lena

    2009-01-01

    The composition and Cl/Br – NaCl ratios of highly saline aqueous inclusions from large tonnage (> 100 t) IOCG deposits (Sossego, Alvo 118, and Igarapé Bahia) and a Paleoproterozoic intrusion-related Cu-Au-(Mo-W-Bi-Sn) deposit (Breves; systems, brine inclusions are Ca-dominated (5 to 10 times more than in porphyry Cu-Au fluids), and contain percent level concentrations of Na and K. IOCG inclusion fluids, however, contain higher Sr, Ba, Pb, and Zn concentrations, but significantly less Bi, than the intrusion-related Breves inclusion fluids. Cu is consistently below detection limits in brine inclusions from the IOCG and intrusion-related systems and Fe was not detected in the latter. Cl/Br and Na/Cl ratios of the IOCG inclusion fluids range from entirely evaporative brines (bittern fluids; e.g. Igarapé Bahia and Alvo 118) to values that indicate mixing with magma-derived brines. Cl/Br and Na/Cl ratios of the Breves inclusion fluids strongly suggest the involvement of magmatic brines, but that possibly also incorporated bittern fluids. Collectively, these data demonstrate that residual evaporative and magmatic brines were important components of the fluid regime involved in the formation of Cu-Au systems in the Carajás Mineral Province.

  8. P-T PHASE DIAGRAM AND GOLD VALENCE STATE OF NEW GOLD MIXED-VALENCE COMPLEXES, Cs2[AuIX2][AuIIIY4](X, Y = Cl, Br, I; X ¹ Y

    Directory of Open Access Journals (Sweden)

    K. Ikeda

    2004-12-01

    Full Text Available Cs2[AuIX2][AuIIIX4](X = Cl, Br, and I is well known for the perovskite-type gold mixed-valence system. This system undergoes pressure-induced and photo-induced Au valence transition from the mixed valence state of AuI,III to the single valence state of AuII. Recently, we have succeeded in synthesizing new gold mixed-valence complexes having perovskite-type structure, Cs2[AuIX2][AuIIIY4](X, Y = halogen, X ¹ Y, in organic solvent by using a new method. This hetero-halogen bridged gold mixed-valence system was confirmed by means of Raman spectroscopy. From the analysis of 197Au Mössbauer spectra, it was elucidated that the charge transfer interaction between AuI(5dx2-y2 and AuIII(5dx2-y2in the a-b plane becomes dominant for the AuI-AuIII interaction in Cs2[AuIX2][AuIIIY4] (X, Y = Cl, Br, and I in the order of X = Cl < Br < I, where Y is fixed. In order to elucidate the Au valence transition for Cs2[AuIX2][AuIIIY4], we have investigated the X-ray diffraction and Raman spectra under high pressure. Moreover, we have synthesized TlAuX3(X = Cl and Br having cubic perovskite structure and highly conducting behavior. The Au valence state in TlAuX3 is considered to be AuII at ambient pressure.

  9. Cu[Au(CN)2]2(DMSO)2: golden polymorphs that exhibit vapochromic behavior.

    Science.gov (United States)

    Lefebvre, Julie; Batchelor, Raymond J; Leznoff, Daniel B

    2004-12-15

    Two polymorphs of an [Au(CN)2]-based coordination polymer, Cu[Au(CN)2]2(DMSO)2, one green (1) and one blue (2), have been identified. In polymorph 1, alternation of five-coordinate Cu(II) and [Au(CN)2]- units generates 1-D chains, while 2-D corrugated sheets are obtained in polymorph 2, which contains six-coordinate Cu(II) centers. Both polymorphs form 3-D networks by virtue of aurophilic interactions of 3.22007(5) A and 3.419(3) A, respectively, and show similar weak antiferromagnetic coupling, but have different thermal decomposition temperatures. They both show vapochromic properties and, importantly, despite their significantly different solid-state structures, the vapochromic behavior of the two polymorphs is essentially identical. Upon solvent exchange, both polymorphs convert to the same Cu[Au(CN)2]2(solvent)x complex (solvent = H2O, CH3CN, dioxane, N,N-dimethylformamide, pyridine, NH3). The Cu[Au(CN)2]2(DMF) and Cu[Au(CN)2]2(pyridine)2 complexes have very similar 2-D square grid structures, comparable to that of 2. The solvent molecules adsorbed by Cu[Au(CN)2]2 bind to the Cu(II) centers, thereby altering the visible spectrum associated with the Cu(II) chromophores and the number and frequency of the nu(CN) as well. The network-stabilizing gold-gold interactions and the flexible coordination sphere of Cu(II) probably facilitate reversible solvent exchange at room temperature.

  10. Cu2O-directed in situ growth of Au nanoparticles inside HKUST-1 nanocages.

    Science.gov (United States)

    Liu, Yongxin; Liu, Ting; Tian, Long; Zhang, Linlin; Yao, Lili; Tan, Taixing; Xu, Jin; Han, Xiaohui; Liu, Dan; Wang, Cheng

    2016-12-07

    Controllable integration of metal nanoparticles (MNPs) and metal-organic frameworks (MOFs) is attracting considerable attention as the obtained composite materials always show synergistic effects in applications of catalysis, delivery, as well as sensing. Herein, a Cu2O-directed in situ growth strategy was developed to integrate Au nanoparticles and HKUST-1. In this strategy, Cu2O@HKUST-1 core-shell heterostructures, HKUST-1 nanocages, Cu2O@Au@HKUST-1 sandwich core-shell heterostructures and Au@HKUST-1 balls-in-cage heterostructures were successfully synthesized. Cu2O@HKUST-1 core-shell heterostructures were synthesized by soaking Cu2O nanocrystals in benzene-1,3,5-tricarboxylic acid solution. The well-defined Cu2O@HKUST-1 core-shell heterostructures were demonstrated to be dominated by the ratio of Cu(2+) cations to btc(3-) ligands in solution during the period of HKUST-1 formation. Cu2O@Au@HKUST-1 sandwich core-shell or Au@HKUST-1 balls-in-cage heterostructures were obtained by impregnating HAuCl4 into Cu2O@HKUST-1 core-shell heterostructures. Due to the porosity of HKUST-1 and reducibility of Cu2O, HAuCl4 could pass through the HKUST-1 shell and be reduced by the Cu2O core in situ forming Au nanoparticles. Finally, CO oxidation reaction at high temperatures was carried out to assess the catalytic functionality of the obtained composite heterostructures. This strategy can circumvent some drawbacks of the existing approaches for integrating MNPs and MOFs, such as nonselective deposition of MNPs at the outer surface of the MOF matrices, extreme treatment conditions and additional surface modifications.

  11. Pion Interferometry in Au+Au and Cu+Cu Collisions at sqrt sNN = 62.4 and 200 GeV

    Energy Technology Data Exchange (ETDEWEB)

    STAR Collaboration; Abelev, B.I.

    2009-08-24

    We present a systematic analysis of two-pion interferometry in Au+Au collisions at {radical}sNN = 62.4 GeV and Cu+Cu collisions at {radical}sNN = 62.4 and 200 GeV using the STAR detector at RHIC. The multiplicity and transverse momentum dependences of the extracted correlation lengths (radii) are studied. The scaling with charged particle multiplicity of the apparent system volume at final interaction is studied for the RHIC energy domain. The multiplicity scaling of the measured correlation radii is found to be independent of colliding system and collision energy.

  12. Large scale structural optimization of trimetallic Cu-Au-Pt clusters up to 147 atoms

    Science.gov (United States)

    Wu, Genhua; Sun, Yan; Wu, Xia; Chen, Run; Wang, Yan

    2017-10-01

    The stable structures of Cu-Au-Pt clusters up to 147 atoms are optimized by using an improved adaptive immune optimization algorithm (AIOA-IC method), in which several motifs, such as decahedron, icosahedron, face centered cubic, sixfold pancake, and Leary tetrahedron, are randomly selected as the inner cores of the starting structures. The structures of Cu8AunPt30-n (n = 1-29), Cu8AunPt47-n (n = 1-46), and partial 75-, 79-, 100-, and 147-atom clusters are analyzed. Cu12Au93Pt42 cluster has onion-like Mackay icosahedral motif. The segregation phenomena of Cu, Au and Pt in clusters are explained by the atomic radius, surface energy, and cohesive energy.

  13. Cu-Au Alloys Using Monte Carlo Simulations and the BFS Method for Alloys

    Science.gov (United States)

    Bozzolo, Guillermo; Good, Brian; Ferrante, John

    1996-01-01

    Semi empirical methods have shown considerable promise in aiding in the calculation of many properties of materials. Materials used in engineering applications have defects that occur for various reasons including processing. In this work we present the first application of the BFS method for alloys to describe some aspects of microstructure due to processing for the Cu-Au system (Cu-Au, CuAu3, and Cu3Au). We use finite temperature Monte Carlo calculations, in order to show the influence of 'heat treatment' in the low-temperature phase of the alloy. Although relatively simple, it has enough features that could be used as a first test of the reliability of the technique. The main questions to be answered in this work relate to the existence of low temperature ordered structures for specific concentrations, for example, the ability to distinguish between rather similar phases for equiatomic alloys (CuAu I and CuAu II, the latter characterized by an antiphase boundary separating two identical phases).

  14. AuCu@Pt Nanoalloys for Catalytic Application in Reduction of 4-Nitrophenol

    Directory of Open Access Journals (Sweden)

    Sadia Mehmood

    2016-01-01

    Full Text Available To enhance and optimize nanocatalyst ability for nitrophenol (4-NP reduction reaction we look beyond Au-metal nanoparticles and describe a new class of Au nanoalloys with controlled composition for core of AuCu-metals and Pt-metal shell. The reduction of 4-NP was investigated in aqueous media spectroscopically on 7.8 nm Au nanospheres (AuNSs, 8.3 nm AuCuNSs, and 9.1 nm AuCu@Pt core-shell NSs in diameter. The rate constants of the catalyzed reaction at room temperature, activation energies, and entropies of activation of reactions catalyzed by the AuCu@Pt core-shell NSs are found to have different values to those of the pure metal NSs. The results strongly support the proposal that catalysis by nanoparticles is taking place efficiently on the surface of NSs. These core-shell nanocatalysts exhibited stability throughout the reduction reaction and proved that heterogonous type mechanisms are most likely to be dominant in nanoalloy based catalysis if the surface of the NSs is not defected upon shell incorporation.

  15. Aide aux femmes ayant survécu à des actes de violence au cours ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Aide aux femmes ayant survécu à des actes de violence au cours des périodes de transition post-conflit en Indonésie, au Timor-Leste et au Myanmar. Les données sur la violence sexuelle à l'égard des femmes et des hommes, tant pendant qu'après les conflits, ont un caractère alarmant dans toutes les régions du monde.

  16. Centrality, Rapidity And Transverse-Momentum Dependence of Cold Nuclear Matter Effects on J/Psi Production in D Au, Cu Cu And Au Au Collisions at S(NN)**(1/2)

    Energy Technology Data Exchange (ETDEWEB)

    Ferreiro, E.G.; /Santiago de Compostela U.; Fleuret, F.; /Ecole Polytechnique; Lansberg, J.P.; /Ecole Polytechnique /SLAC; Rakotozafindrabe, A.; /SPhN, DAPNIA, Saclay

    2011-11-11

    We have carried out a wide study of Cold Nuclear Matter (CNM) effects on J/{Psi} = production in dAu, CuCu and AuAu collisions at {radical}s{sub NN} = 200 GeV. We have studied the effects of three different gluon-shadowing parameterizations, using the usual simplified kinematics for which the momentum of the gluon recoiling against the J/{Psi} is neglected as well as an exact kinematics for a 2 {yields} 2 process, namely g + g {yields} J/{psi} + g as expected from LO pQCD. We have shown that the rapidity distribution of the nuclear modification factor R{sub dAu}, and particularly its anti-shadowing peak, is systematically shifted toward larger rapidities in the 2 {yields} 2 kinematics, irrespective of which shadowing parameterization is used. In turn, we have noted differences in the effective final-state nuclear absorption needed to fit the PHENIX dAu data. Taking advantage of our implementation of a 2 {yields} 2 kinematics, we have also computed the transverse momentum dependence of the nuclear modification factor, which cannot be predicted with the usual simplified kinematics. All the corresponding observables have been computed for CuCu and AuAu collisions and compared to the PHENIX and STAR data. Finally, we have extracted the effective nuclear absorption from the recent measurements of RCP in dAu collisions by the PHENIX collaboration.

  17. Geografia do trabalho no Brasil Géographie du travail au Brésil

    Directory of Open Access Journals (Sweden)

    Alexandre Gori Maia

    2009-06-01

    ídos do país. A área mais contígua de municípios mais desenvolvidos ocorre próxima aos dois principais estados brasileiros, São Paulo e Rio de Janeiro, além de importantes bolsões de desenvolvimento próximos à faixa litorânea. Os municípios rurais menos desenvolvidos, por sua vez, predominam nas áreas do semi-áridas do país, na floresta amazônica e na tríplice fronteira com os países do Mercosul.L'article traite de la configuration territoriale du travail au Brésil par l'analyse des structures d'activité et des rémunérations à l'échelle des municipes: la combinaison entre les catégories socio-professionnelles et les classes de salaire informe sur les niveaux de développement socio-économique des municipes et sur les inégalités du territoire brésilien. La profession est plus ou moins favorable en termes de revenus, mais elle a aussi des conséquences en termes de prestige social et de pouvoir politique. Compte tenu de l'extrême inégalité des salaires au Brésil, même dans des catégories professionnelles relativement homogènes, l'article prend le montant de salaire de l'activité principale comme second critère de classification. L'analyse statistique multivariée à partir des informations du recensement démographique de 2000 donne matière à une carte qui donne à voir une hiérarchie socio-économique des municipes brésiliens. La plupart des municipes pauvres  présentent des activités agricoles dominantes et  comptent beaucoup de travailleurs à bas salaire. Les municipes urbains les plus développés  concentrent une bonne partie de la population brésilienne et comptent à la fois beaucoup de personnes dans les strates de revenus élevées et beaucoup d'exclus. Les zones contiguës à ces municipes se trouvent à proximité des Etats de Sao Paulo et de Rio de Janeiro, ainsi que près du littoral. Les municipes ruraux les moins développés se trouvent, eux, dans la zone semi-aride, dans la forêt amazonienne et près de la

  18. Nucleon shadowing effects in Cu + Cu and Au + Au collisions at RHIC within the HIJING code

    Science.gov (United States)

    Abdel-Waged, Khaled; Felemban, Nuha

    2018-02-01

    The centrality dependence of pseudorapidity density of charged particles ({{{d}}{N}}{{ch}}/{{d}}η ) in Cu + Cu (Au + Au) collisions at Relativistic Heavy Ion Collider energy of \\sqrt{{s}{{NN}}}=22.4, 62.4 and 200 (19.6, 62.4 and 200) GeV, is investigated within an improved HIJING code. The standard HIJING model is enhanced by a prescription for collective nucleon–nucleon (NN) interactions and more modern parton distribution functions. The collective NN-interactions are used to induce both cascade and nucleon shadowing effects. We find collective cascade broadens the pseudorapidity distributions in the tails (at | η | > {y}{beam}) above 25%–30% collision centrality to be consistent with the {{{d}}{N}}{{ch}}/{{d}}η data at \\sqrt{{s}{{NN}}} =19.6,22.4,62.4 {GeV}. The overall contribution of nucleon shadowing is shown to depress the whole shape of {{{d}}{N}}{{ch}}/{{d}}η in the primary interaction region (at | η | < {y}{beam}) for semiperipheral (20%–25%) and peripheral (≥slant 35 % {--}40 % ) Cu + Cu (Au + Au) interactions at \\sqrt{{s}{{NN}}}=200 {GeV}, in accordance with the PHOBOS data.

  19. On forge des partenariats au Brésil | CRDI - Centre de recherches ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    9 mai 2011 ... La collaboration entre les différents établissements brésiliens reconnus dans leur champ d'expertise donne du poids aux arguments quand il s'agit de s'adresser aux décideurs, conclut Mme Padua. Instituto de Pesquisas Ecologicas, Brésil Fundação Oswaldo Cruz (FIOCRUZ), Brésil Faculté de médecine ...

  20. Ar+ and CuBr laser-assisted chemical bleaching of teeth: estimation of whiteness degree

    Science.gov (United States)

    Dimitrov, S.; Todorovska, Roumyana; Gizbrecht, Alexander I.; Raychev, L.; Petrov, Lyubomir P.

    2003-11-01

    In this work the results of adaptation of impartial methods for color determination aimed at developing of techniques for estimation of human teeth whiteness degree, sufficiently handy for common use in clinical practice are presented. For approbation and by the way of illustration of the techniques, standards of teeth colors were used as well as model and naturally discolored human teeth treated by two bleaching chemical compositions activated by three light sources each: Ar+ and CuBr lasers, and a standard halogen photopolymerization lamp. Typical reflection and fluorescence spectra of some samples are presented; the samples colors were estimated by a standard computer processing in RGB and B coordinates. The results of the applied spectral and colorimetric techniques are in a good agreement with those of the standard computer processing of the corresponding digital photographs and complies with the visually estimated degree of the teeth whiteness judged according to the standard reference scale commonly used in the aesthetic dentistry.

  1. Au plasmonics in a WS{sub 2}-Au-CuInS{sub 2} photocatalyst for significantly enhanced hydrogen generation

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Zhongzhou [CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190 (China); School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Wang, Zhenxing, E-mail: wangzx@nanoctr.cn, E-mail: hej@nanoctr.cn; Shifa, Tofik Ahmed; Wang, Fengmei; Zhan, Xueying; Xu, Kai; He, Jun, E-mail: wangzx@nanoctr.cn, E-mail: hej@nanoctr.cn [CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190 (China); Liu, Quanlin [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-11-30

    Promoting the activities of photocatalysts is still the critical challenge in H{sub 2} generation area. Here, a Au plasmon enhanced photocatalyst of WS{sub 2}-Au-CuInS{sub 2} is developed by inserting Au nanoparticles between WS{sub 2} nanotubes and CuInS{sub 2} (CIS) nanoparticles. Due to the localized surface plasmonic resonance properties from Au nanoparticles, WS{sub 2}-Au-CIS shows the best performance as compared to Au-CIS, CIS, WS{sub 2}-CIS, CIS-Au, WS{sub 2}-Au, and WS{sub 2}-CIS-Au. The surface plasmonic resonance effects dramatically intensify the absorption of visible light and help to inject hot electrons into the semiconductors. Our findings open up an efficient method to optimize the type-II structures for photocatalytic water splitting.

  2. Electric fields and chiral magnetic effect in Cu+Au collisions

    Directory of Open Access Journals (Sweden)

    Wei-Tian Deng

    2015-03-01

    Full Text Available The non-central Cu+Au collisions can create strong out-of-plane magnetic fields and in-plane electric fields. By using the HIJING model, we study the general properties of the electromagnetic fields in Cu+Au collisions at 200 GeV and their impacts on the charge-dependent two-particle correlator γq1q2=〈cos⁡(ϕ1+ϕ2−2ψRP〉 (see main text for definition which was used for the detection of the chiral magnetic effect (CME. Compared with Au+Au collisions, we find that the in-plane electric fields in Cu+Au collisions can strongly suppress the two-particle correlator or even reverse its sign if the lifetime of the electric fields is long. Combining with the expectation that if γq1q2 is induced by elliptic-flow driven effects we would not see such strong suppression or reversion, our results suggest to use Cu+Au collisions to test CME and understand the mechanisms that underlie γq1q2.

  3. Field-controlled magnetic order in the quantum spin-ladder system (Hpip)2CuBr4

    DEFF Research Database (Denmark)

    Thielemann, B.; Rüegg, C.; Kiefer, K.

    2009-01-01

    Neutron diffraction is used to investigate the field-induced, antiferromagnetically ordered state in the two-leg spin-ladder material (Hpip)(2)CuBr4. This "classical" phase, a consequence of weak interladder coupling, is nevertheless highly unconventional: its properties are influenced strongly b...... the quantum fluctuation corrections to the mean-field interaction....

  4. Electrical and optical properties of hybrid polymer solar cells incorporating Au and CuO nanoparticles

    Directory of Open Access Journals (Sweden)

    Aruna P. Wanninayake

    2015-12-01

    Full Text Available In this study, to enhance the power conversion efficiency (PCE of the polymer solar cells (PSCs, Gold (Au and Copper oxide nanoparticles (CuO-NPs are incorporated into the PEDOT:PSS and P3HT/PCBM active layers respectively. PSCs with a constant CuO-NP content were fabricated with varying amounts of Au NPs. Addition of Au NPs increased the power conversion efficiency by up to 18% compared to a reference cell without Au-NPs. The short circuit current(Jsc of the cells containing 0.06 mg of Au NPs was measured at 7.491 mA/cm2 compared to 6.484 mA/cm2 in the reference cells with 0.6 mg of CuO nanoparticles; meanwhile, the external quantum efficiency(EQE increased from 53% to 61%, showing an enhancement of 15.1%. Au-NPs improved the charge collection at the anode, which results in higher short circuit current and fill factor. However, the strong near field surrounding Au-NPs due to localized surface plasmonic resonance (LSPR effect is not distributed into the active layer. Instead, it is spread horizontally through the PEDOT:PSS layer, thus minimizing the light absorption in the active layer.

  5. Surface Morphology and Electrical Resistivity in Polycrystalline Au/Cu/Si(100 System

    Directory of Open Access Journals (Sweden)

    T. E. Novelo

    2017-01-01

    Full Text Available This work describes the analysis of morphology and electrical resistivity (ρ obtained in the Au/Cu/Si system. The Au/Cu bilayers were deposited by thermal evaporation technique with thicknesses from 50 to 250 nm on SiOx/Si(100 substrates. The Au : Cu concentration ratio of the samples was of 25 : 75 at%. The bilayers were annealed into a vacuum oven with argon atmosphere at 660 K for one hour. The crystalline structures of AuCu and CuSi alloys were confirmed by X-ray diffraction analysis. The scanning electron microscopy (SEM, the atomic force microscopy (AFM, and the energy dispersive spectroscopy (EDS were used to study the morphology, final thickness, and the atomic concentration of the alloys formed, respectively. The four-point probe technique was used to measure the electrical resistivity (ρ in the prepared alloys as a function of thickness. The ρ value was measured and it was numerically compared with the Fuchs–Sondheimer (FS and the Mayadas–Shatzkes (MS models of resistivity. Results show values of electrical resistivity between 0.9 and 1.9 μΩ-cm. These values are four times smaller than the values of the AuCu systems reported in literature.

  6. In situ TEM observation of novel chemical evolution of MnBr2 catalyzed by Cu under electron beam irradiation

    Science.gov (United States)

    Wang, Wei; Bai, Xianwei; Guan, Xiangxiang; Shen, Xi; Yao, Yuan; Wang, Yanguo; Zou, Bingsuo; Yu, Richeng

    2017-10-01

    Manganese bromide has attracted enormous attention for its applications in the syntheses of organic-inorganic hybrid compounds. A complete understanding of structural and chemical stabilities of MnBr2 is important for controlling its properties. Here, we focus on the irradiation resistance of MnBr2. The chief purpose of this research is reached by in situ transmission electron microscopy. It is demonstrated that the deliquescent MnBr2 powder is prone to adsorb the vapor in air, and the hydrous MnBr2 can be decomposed under its continuous exposure to electron beam, indicated by a transmission electron microscope via the catalysis of Cu grid at room temperature.

  7. Molecular Dynamics Simulation of Nanoindentation of Cu/Au Thin Films at Different Temperatures

    Directory of Open Access Journals (Sweden)

    Qibin Li

    2016-01-01

    Full Text Available Two methods, deposition method and ideal modeling based on lattice constant, are used to prepare three modulation periods’ (1.8 nm Cu/3.6 nm Au, 2.7 nm Cu/2.7 nm Au, and 3.6 nm Cu/1.8 nm Au thin films for nanoindentation at different temperatures. The results show that the temperature will weaken the hardness of thin films. The deposition method and the formation of coherent interface will result in a lot of defects in thin films. These defects can reduce the residual stress in the thin films which is caused by the external force. The proposed system will provide potential benefits in designing the microstructures for thin films.

  8. Competing mechanisms for ordering tendencies in BCC CuAuZn{sub 2} and FCC AuFe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.D.; Althoff, J.D. [Sandia National Labs., Livermore, CA (United States); Staunton, J.B.; Ling, M.F. [Warwick Univ., Coventry (United Kingdom). Dept. of Physics; Pinski, F.J. [Cincinnati Univ, OH (United States). Dept. of Physics

    1995-07-01

    We have briefly discussed the ASRO (atomic short-range order) in AuFe and CuAuZn{sub 2}. General points are that (1) we have implemented a first-principles theory of ASRO in N-component alloys which allows determination of the electronic origins of said ASRO; (2) such calculations can provide much information on the high- and (sometimes) low-temperature alloys; and (3) this approach has identified the origin for the novel special-point ASRO in AuFe. Displacement effects, i.e., non-rigid lattice effects, as well as the other contributions beyond band-energy, are being incorporated into the multicomponent alloy calculations. Such improvements will allow us to investigate other alloys, where charge effects may play a role, to ``design`, for example, higher temperature intermetallics through alloying.

  9. Mixed Cu(i)/Au(i) coordination polymers as reversible turn-on vapoluminescent sensors for volatile thioethers.

    Science.gov (United States)

    Varju, Bryton R; Ovens, Jeffrey S; Leznoff, Daniel B

    2017-06-13

    Vapour-phase thioethers play an important role in a wide number of fields, including plant biology, chemical weapon disposal, and brewing but few sensor materials are known. The emissive coordination polymer Cu1/2Au1/2CN does not react with vapour phase dimethyl sulphide (DMS) or diethyl sulphide (DES) despite the independent synthesis of emissive [Cu1/2Au1/2CN]2(DMS) and [Cu1/2Au1/2CN]2(DES) from their constituent components in solution. However, the doped Cu2/3Au1/3CN rapidly reacts in the solid state with both of these vapour phase thioethers reversibly, with a change in emission from 380/560 nm to 460 nm (DMS) or 420 nm (DES), illustrating that doping the inactive parent Cu1/2Au1/2CN with Cu(i) generates an active sensor material. This response can be thermally cycled with little to no loss in functionality. [Cu1/2Au1/2CN]2(DMS), [Cu2/3Au1/3CN]2(DMS), and [Cu2/3Au1/3CN]2(DES) were structurally characterized as 3-D network structures supported by aurophilic interactions.

  10. Anisotropic Flow in sqrt(s_NN) = 200 GeV Cu+Cu and Au+Au collisions at PHENIX

    CERN Document Server

    Masui, H

    2006-01-01

    We report the measurement of anisotropic flow at RHIC - PHENIX experiment. We present the v_4 results at sqrt(s_NN) = 200 GeV in Au+Au collision. The scaling ratio of v_4/(v_2)^2 is about 1.5 and it is found to be smaller than the prediction from simple coalescence model. The v_2 for high p_T identified particles ($\\sim$ 5 GeV/c) measured with Aerogel Cherenkov Counter are presented. We discuss the constituent quark scaling of v_2 for identified particles. We also report the first observation of v_2 for inclusive charged hadrons as well as identified hadrons at sqrt(s_NN) = 200 GeV in Cu+Cu collisions. The system size dependence of v_2 and scaling properties are discussed.

  11. Topological description of mechanical behavior of Cu, Ag and Au: A first-principle study

    Directory of Open Access Journals (Sweden)

    M Saghayezhian

    2011-12-01

    Full Text Available  Mechanical properties and stress-strain curves of Cu, Ag and Au single crystals are calculated using ab initio methods. Elastic and Plastic regions are scrutinized. Yield stress and slope of these curves can shed light on brittlenesss and ductility of these metals that prove Cu, despite its high ultimate tensile strength, is less ductile than Au and Ag. Analysis of topology of charge density along with stress-strain curves shows that the elastic-plastic transition accompanies topological transition and for these metals, both transitions occur in the same strain. Some charactristics of critical point, especially bond points, are inspected.

  12. Structural control and (remobilization of the extinct Haveri Au-Cu deposit, southern Finland

    Directory of Open Access Journals (Sweden)

    Nironen, M.

    1994-06-01

    Full Text Available The extinct Haveri Au-Cu deposit is located within mafic metalavas and mafic/ intermediate banded rocks of the Haveri Formation, in the western part of the Paleoproterozoic Tampere Schist Belt. The sulfide-bearing banded rocks display a large E-W trending fold structure in magnetic and electromagnetic maps. Field evidence suggest that the Au-Cu deposit is in a F1/F2 fold interferrence pattern in the western core of the large fold. The ore-forming elements concentrated into the F1 fold closure during D1 deformation. Sulfide-bearing fractures subparallel to S2 spaced cleavage indicate slight remobilization during D2.

  13. Futebol et hiérarchies urbaines au Brésil.

    Directory of Open Access Journals (Sweden)

    Hervé Théry

    2006-03-01

    Full Text Available Le football n’est pas seulement la passion nationale du Brésil, il peut être aussi un bon indicateur des hiérarchies urbaines du pays. Les classements disponibles sur le site de la fédération brésilienne de futebol peuvent être mis en rapport avec d’autres données pour vérifier la corrélation entre les performances sportives des clubs et le degré de centralité des villes où ils sont basés.

  14. 3D Modelling of the Plavica Au-Cu polymetallic deposit, Republic of Macedonia

    OpenAIRE

    Igor IVANOVSKI; Serafimovski, Dalibor; Tasev, Goran; Serafimovski, Todor

    2015-01-01

    The latest exploration and study of the high sulfidation epithermal deposit of Plavica displayed significant progress in understanding the geology and definition of the particular ore body. The results from boreholes made by Genesis Resources International DOOEL Skopje, Republic of Macedonia, in 2011, 2012 and 2013 were: 51 m interval with 3.9 g/t Au in oxidation zone, 65 m interval with 3.1 g/t Au in oxidation zone, 51 m interval with 3.7 g/t Au, 2.8% Cu and 16 g/t Ag in sulfide zone. For...

  15. Band Structure and Optical Properties of Ordered AuCu3

    DEFF Research Database (Denmark)

    Skriver, Hans Lomholt; Lengkeek, H. P.

    1979-01-01

    initio band structure obtained by the relativistic linear muffin-tin orbitals method. The band calculation reveals that ordered AuCu3 has distinct copper and gold d bands positioned in and hybridizing with an s band common to copper and gold. The calculated state density is found to be in good agreement...

  16. Nanocrystallization of Zr-Cu-Ni-Al-Au glassy alloys during severe plastic deformation

    Science.gov (United States)

    Yamada, Masahiro; Kamisato, Ryo; Yamasaki, Tohru; Adachi, Hiroki; Tsuchiya, Koichi; Yokoyama, Yoshihiko

    2014-08-01

    A study has been carried out into the formation of nanocrystalline grains during high-pressure torsion (HPT) deformation of Zr65Cu17Ni5Al10Au3 bulk alloys prepared using tilt casting. As a preliminary to this, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses were carried out on as-cast Zr65+xCu17-xNi5Al10Au3 (x=0~5 at.%) and Zr65Cu20Ni5Al10Au3 alloys, in order to determine the effect on the microstructure of the excess Zr content x and the presence of Au. From the XRD patterns, it was determined that all of the alloys had a metallic glassy nature. For Zr65Cu17Ni5Al10Au3, the DSC results indicated the presence of a wide supercooled liquid region between the glass transition temperature (Tg) of 644 K and the crystallization temperature of 763 K, where the stable body-centered tetragonal Zr2Cu phase was formed. In contrast, for the Zr65+xCu17-xNi5Al10Au3 alloys, precipitation of an icosahedral quasicrystalline phase (I-phase) was observed in the supercooled liquid region at about 715 K. HPT deformation of the Zr65Cu17Ni5Al10Au3 alloys was carried out under a high pressure of 5 GPa. Both as-cast specimens and those annealed at Tg-50 K for 90 min were used. Following a single HPT rotation (N=1), transmission electron microscopy identified the presence of face- centered cubic Zr2Ni precipitates in the as-cast alloy, with a size of about 50 nm. For the annealed alloy, a high density of I-phase precipitates with sizes of less than 10 nm was observed following HPT with N=10, indicating that the combination of severe plastic deformation and annealing is effective at producing extremely small grains.

  17. Magnetism of CuCl2·2D2O and CuCl2·2H2O, and of CuBr2·6H2O

    Science.gov (United States)

    DeFotis, G. C.; Hampton, A. S.; Van Dongen, M. J.; Komatsu, C. H.; Benday, N. S.; Davis, C. M.; Hays, K.; Wagner, M. J.

    2017-07-01

    The magnetic properties of little examined CuCl2·2D2O are studied and compared with those of CuCl2·2H2O. New CuBr2·6H2O is also examined. Susceptibility maxima appear for chlorides at 5.35 and 5.50 K, in the above order, with estimated antiferromagnetic ordering at 4.15 and 4.25 K. Curie-Weiss fits yield g of 2.210 and 2.205, and Weiss θ of -6.0 and -4.7 K, respectively, in χM = C/(T - θ). One-dimensional Heisenberg model fits to susceptibilities, including interchain exchange in a mean-field approximation, are performed. Interchain exchange is significant but much weaker than intrachain. The bromide hexahydrate strongly differs magnetically from any chloride hydrate, but exhibits notable similarities and differences compared to previously studied CuBr2. A broad susceptibility maximum occurs near 218 K, only 4% lower than for CuBr2, but with almost twice the magnitude. Powder X-ray diffraction data for CuBr2·6H2O may be best accounted for by a monoclinic unit cell that is metrically orthorhombic. The volume per formula unit is consistent with trends in metal ionic radii. However, an alternative monoclinic cell with 5% smaller volume more readily rationalizes the magnetism.

  18. Correlating Cu-sulfide and Au mineralization in the Ertsberg-Grasberg District using LA-ICP-MS and HRXCT

    Science.gov (United States)

    Wright, K. A.; Miller, N. R.; Ketcham, R. A.; Kyle, R.

    2016-12-01

    The Ertsberg-Grasberg district in Papua, Indonesia, hosts to two of the largest intrusion-related Cu-Au deposits in the world: the Ertsberg East Skarn system and the Grasberg Intrusive Complex. Cu mineralization within the Grasberg porphyry and Ertsberg skarn systems primarily consists of bornite and chalcopyrite, with minor digenite and idiate. Native Au is commonly found in association with Cu mineralization where Au occurs as inclusions within or immediately proximal to primary Cu-sulfide minerals. At hydrothermal-ore forming temperatures, approximately 400° to 700° C, bornite and chalcopyrite can host up to 1800 ppm Au within the Cu-sulfide lattice. Upon retrograde cooling of the hydrothermal system, the ability of bornite and chalcopyrite to host Au decreases significantly to about 10 ppm, indicating that the Au could be expulsed from the sulfide lattice. Given the close association of native Au and Cu-sulfide concentrations, it is possible that native gold grains form as the Au emerges from the Cu-sulfides. Constraining the genetic and spatio-temporal relationship between Cu-sulfide and Au mineralization within these deposits is of significant interest with regard to the geometallurgical processing of the ore, and to future exploration. This study seeks to evaluate this relationship using High Resolution X-ray Computed Tomography (HRXCT) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). Previous HRXCT studies on Ertsberg-Grasberg ore samples have identified numerous occurrences of native Au grains at the edges of Cu-sulfide masses. HRXCT data are used here to construct 3D Voronoi regions of potential Au "diffusional drainage" from within the Cu-sulfides, where the expectation is a positive correlation between Au grain size and modified Voronoi polyhedron volume, defined as the volume of sulfide closer to that grain than any other via a connected path through sulfide. LA-ICP-MS data are used to determine variations in Au contents

  19. Construction of CuS/Au Heterostructure through a Simple Photoreduction Route for Enhanced Electrochemical Hydrogen Evolution and Photocatalysis

    Science.gov (United States)

    Basu, Mrinmoyee; Nazir, Roshan; Fageria, Pragati; Pande, Surojit

    2016-01-01

    An efficient Hydrogen evolution catalyst has been developed by decorating Au nanoparticle on the surface of CuS nanostructure following a green and environmental friendly approach. CuS nanostructure is synthesized through a simple wet-chemical route. CuS being a visible light photocatalyst is introduced to function as an efficient reducing agent. Photogenerated electron is used to reduce Au(III) on the surface of CuS to prepare CuS/Au heterostructure. The as-obtained heterostructure shows excellent performance in electrochemical H2 evolution reaction with promising durability in acidic condition, which could work as an efficient alternative for novel metals. The most efficient CuS-Au heterostructure can generate 10 mA/cm2 current density upon application of 0.179 V vs. RHE. CuS-Au heterostructure can also perform as an efficient photocatalyst for the degradation of organic pollutant. This dual nature of CuS and CuS/Au both in electrocatalysis and photocatalysis has been unveiled in this study. PMID:27703212

  20. Covellite CuS as a matrix for "invisible" gold: X-ray spectroscopic study of the chemical state of Cu and Au in synthetic minerals

    Science.gov (United States)

    Tagirov, Boris R.; Trigub, Alexander L.; Kvashnina, Kristina O.; Shiryaev, Andrey A.; Chareev, Dmitriy A.; Nickolsky, Maximilian S.; Abramova, Vera D.; Kovalchuk, Elena V.

    2016-10-01

    Geological processes leading to formation of sulfide ores often result in precipitation of gold-bearing sulfides which can contain high concentrations of this metal in ;invisible; (or ;refractory;) state. Covellite (CuS) is ubiquitous mineral in many types of the ore deposits, and numerous studies of the natural ores show that covellite can contain high concentrations of Au. At the same time, Au-bearing covellite withstands cooling in contrast to other minerals of the Cu-Fe-S system (chalcocite, bornite, chalcopyrite), where Au exsolves at low temperatures. This makes covellite a convenient model system for investigation of the chemical state (local environment and valence) of the ;invisible; Au in copper-sulfide ores (copper-porphyry, epithermal, volcanogenic massive sulfide, SEDEX deposits). Therefore, it is necessary to determine the location of Au in the covellite matrix as it will have important implications for the methods employed by mineral processing industry to extract Au from sulfide ores. Here we investigate the chemical state of Cu and Au in synthetic covellite containing up to 0.3 wt.% of Au in the ;invisible; state. The covellite crystals were synthesized by hydrothermal and salt flux methods. Formation of the chemically bound Au is indicated by strong dependence of the concentration of Au in covellite on the sulfur fugacity in the experimental system (d(log C(Au))/d(log f(S2)) ∼ 0.65). The Au concentration of covellite grows with increasing temperature from 400 to 450 °C, whereas further temperature increase to 500 °C has only minor effect. The synthesized minerals were studied using X-ray absorption fine structure spectroscopy (XAFS) in high energy resolution fluorescence detection (HERFD) mode. Ab initio simulations of Cu K edge XANES spectra show that the Cu oxidation state in two structural positions in covellite (tetrahedral and triangular coordination with S atoms) is identical: the total loss of electronic charge for the 3d shell is ∼0

  1. Are Corporate Universities (CU possible in emerging countries? Arcor University (AU.

    Directory of Open Access Journals (Sweden)

    Leandro A. Viltard

    2014-09-01

    Full Text Available This article explores CU implementation and whether it is applicable and effective in emerging countries like Argentina (where there are no studies on the subject. Through an in-depth review of Arcor University (AU, Arcor’s Group CU, located in Argentina, the feasibility of the CU is shown, under certain conditions. This analysis is complemented with specialists´ interviews to deepen our insights and investigation’s results. Our conclusion is that the CU complements Corporate Training’s traditional offering, as its programs are directed towards practical contents and performance/organizational improvement. In this way, it is possible to enhance the actual corporate educational paradigm and talent employability. The research design is not experimental and is transversal as it relates to a specific moment in time.

  2. Atomistic modelling of friction of Cu and Au nanoparticles adsorbed on graphene

    Directory of Open Access Journals (Sweden)

    A.V. Khomenko

    2013-01-01

    Full Text Available We present classical molecular dynamics calculations of the behavior of copper and gold nanoparticles on a graphene sheet, sheared with a constant applied force Fa. The force Fs acting on the particle from the substrate depends on the material of the nanoparticles (Au or Cu, and exhibits a sawtooth dependency on time, which we attribute to local commensurability between the metal nanoparticle surface atomic positions with the graphene lattice. The time-averaged value of Fs (the friction force acting on Au nanoparticles increases linearly with the contact area, having slopes close to the experimentally observable ones. A qualitative model is proposed to explain the observed results.

  3. 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.

  4. Stopping power of Au for Cu ions with energies below Bragg's peak

    Energy Technology Data Exchange (ETDEWEB)

    Linares, R.; Freire, J.A. [Departamento de Fisica Nuclear Instituto de Fisica, Universidade de Sao Paulo, CP 66318, 05314-970 Sao Paulo, SP (Brazil); Ribas, R.V. [Departamento de Fisica Nuclear Instituto de Fisica, Universidade de Sao Paulo, CP 66318, 05314-970 Sao Paulo, SP (Brazil)], E-mail: ribas@if.usp.br; Medina, N.H.; Oliveira, J.R.B.; Cybulska, E.W.; Seale, W.A.; Added, N.; Silveira, M.A.G.; Wiedemann, K.T. [Departamento de Fisica Nuclear Instituto de Fisica, Universidade de Sao Paulo, CP 66318, 05314-970 Sao Paulo, SP (Brazil)

    2007-10-15

    The stopping power of Au for Cu in the energy range 6 < E < 25 MeV was measured using a secondary beam of low velocity heavy ions produced by elastic scattering of an energetic primary beam (typically {sup 28}Si or {sup 16}O) on a natural Cu target. The results were compared to predictions of the Lindhard, Scharf and Schiott (LSS) theory, the binary theory (BT), and the unitary convolution approximation (UCA) and also to semi-empirical predictions such as the Northcliffe and Schilling tables and the SRIM2003 computer program.

  5. Charged hadron multiplicity fluctuations in Au+Au and Cu+Cu collisions from sqrt(s_NN) = 22.5 to 200 GeV

    CERN Document Server

    Adare, A; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Al-Bataineh, H; Alexander, J; Al-Jamel, A; Aoki, K; Aphecetche, L; Armendariz, R; Aronson, S H; Asai, J; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Baksay, G; Baksay, L; Baldisseri, Alberto; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bauer, F; Bazilevsky, A; Belikov, S; Bennett, R; Berdnikov, Y; Bickley, A A; Bjorndal, M T; Boissevain, J G; Borel, H; Boyle, K; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Büsching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Campbell, S; Chai, J S; Chand, P; Chang, B S; Chang, W C; Charvet, J L; Chernichenko, S; Chiba, J; Chi, C Y; Chiu, M; Choi, I J; Choudhury, R K; Chujo, T; Chung, P; Churyn, A; Cianciolo, V; Cleven, C R; Cobigo, Y; Cole, B A; Comets, M P; Constantin, P; Csanad, M; Csrgo, T; Cussonneau, J P; Dahms, T; Das, K; Dávid, G; Dek, F; Deaton, M B; Dehmelt, K; Delagrange, oa H; Denisov, A; d'Enterria, D; Deshpande, A; Desmond, E J; Devismes, A; Dietzsch, O; Dion, A; Donadelli, M; Drachenberg, J L; Drapier, O; Drees, A; Dubey, A K; Durum, A; Dutta, D; Dzhordzhadze, V; Efremenko, Yu V; Egdemir, J; Ellinghaus, F; Emam, W S; Enokizono, A; Enyo, H; Espagnon, B; Esumi, S; Eyser, K O; Fields, D E; Finck, C; Finger, M; Finger, M; Fleuret, F; Fokin, S L; Forestier, B; Fox, B D; Fraenkel, Zeev; Frantz, J E; Franz, A; Frawley, A D; Fujiwara, K; Fukao, Y; Fung, S Y; Fusayasu, T; Gadrat, S; Garishvili, I; Gastineau, F; Germain, M; Glenn, A; Gong, H; Gonin, M; Gosset, J; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grosse-Perdekamp, M; Gunji, T; Gustafsson, H; Hachiya, T; Hadj Henni, A; Haegemann, C; Haggerty, J S; Hagiwara, M N; Hamagaki, AH; Han, R; Hansen, A G; Harada, H; Hartouni, E P; Haruna, K; Harvey, M; Haslum, E; Hasuko, K; Hayano, R; Heffner, M; Hemmick, T K; Hester, T; Heuser, J M; He, X; Hidas, P; Hiejima, H; Hill, J C; Hobbs, R; Hohlmann, M; Holmes, M; Holzmann, W; Homma, K; Hong, B; Hoover, A; Horaguchi, T; Hornback, D; Hur, M G; Ichihara, T; Ikonnikov, V V; Imai, K; Inaba, M; Inoue, Y; Inuzuka, M; Isenhower, D; Isenhower, L; Ishihara, M; Isobe, T; Issah, M; Isupov, A; Jacak, B V; Jia, J; Jin, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kajihara, F; Kametani, S; Kamihara, N; Kamin, J; Kaneta, M; Kang, J H; Kanou, H; Katou, K; Kawabata, T; Kawagishi, T; Kawall, D; Kazantsev, A V; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, E; Kim, G B; Kim, H J; Kim, Y S; Kinney, E; Kiss, A; Kistenev, E; Kiyomichi, A; Klay, J; Klein-Bösing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Kohara, R; Komkov, B; Konno, M; Kotchetkov, D; Kozlov, A; Krl, A; Kravitz, a A; Kroon, P J; Kubart, J; Kuberg, C H; Kunde, G J; Kurihara, N; Kurita, K; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Le Bornec, Y; Leckey, S; Lee, D M; Lee, M K; Lee, T; Leitch, M J; Leite, M A L; Lenzi, B; Lim, H; Lika, T; Litvinenko, s A; Liu, M X; Li, X; Li, X H; Love, B; Lynch, D; Maguire, C F; Makdisi, Y I; Malakhov, A; Malik, M D; Man'ko, V I; Mao, Y; Martínez, G; Maek, L; Masui, H; Matathias, F; Matsumoto, T; McCain, M C; McCumber, M; McGaughey, P L; Miake, Y; Mike, P; Miki, K; Miller, sT E; Milov, A; Mioduszewski, S; Mishra, G C; Mishra, M; Mitchell, J T; Mitrovski, M; Mohanty, A K; Morreale, A; Morrison, D P; Moss, J M; Moukhanova, T V; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagata, Y; Nagle, J L; Naglis, M; Nakagawa, I; Nakamiya, Y; Nakamura, T; Nakano, K; Newby, J; Nguyen, M; Norman, B E; Nyanin, A S; Nystrand, J; O'Brien, E; Oda, S X; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, H; Okada, K; Oka, M; Omiwade, O O; Oskarsson, A; Otterlund, I; Ouchida, M; Oyama, K; Ozawa, K; Pak, R; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, J; Park, W J; Pate, S F; Pei, H; Penev, V; Peng, J C; Pereira, H; Peresedov, V; Peressounko, D Yu; Pierson, A; Pinkenburg, C; Pisani, R P; Purschke, M L; Purwar, A K; Qualls, J M; Qu, H; Rak, J; Rakotozafindrabe, A; Ravinovich, I; Read, K F; Rembeczki, S; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosendahl, S S E; Rosnet, P; Rukoyatkin, P; Rykov, V L; Ryu, S S; Sahlmueller, B; Saitô, N; Sakaguchi, T; Sakai, S; Sakata, H; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Seele, J; Seidl, R; Semenov, V; Seto, R; Sharma, D; Shea, T K; Shein, I; Shevel, A; Shibata, T A; Shigaki, K; Shimomura, M; Shohjoh, T; Shoji, K; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, C P; Singh, V; Skutnik, S; Sluneka, M; Smith, W C; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, cS P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Suire, C; Sullivan, J P; Sziklai, J; Tabaru, T; Takagi, S; Takagui, E M; Taketani, A; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Taranenko, A; Tarjn, P; Thomas, a T L; Togawa, M; Toia, A; Tojo, J; Tomaek, L; Torii, H; Towell, R S; Tram, V-N; Tserruya, Itzhak; Tsuchimoto, Y; Tuli, S K; Tydesj, H; Tyurin, N; Uam, T J; Vale, C; Valle, H; van Hecke, o H W; Velkovska, J; Velkovsky, M; Vertesi, R; Veszprmi, V; Vinogradov, A A; Virius, M; Volkov, e M A; Vrba, V; Vznuzdaev, E; Wagner, M; Walker, D; Wang, X R; Watanabe, Y; Wessels, J; White, S N; Willis, N; Winter, D; Wohn, F K; Woody, C L; Wysocki, M; Xie, W; Yamaguchi, Y L; Yanovich, A; Yasin, Z; Ying, J; Yokkaichi, S; Young, G R; Younus, I; Yushmanov, I E; Zajc, W A; Zaudtke, O; Zhang, C; Zhou, S; Zimányi, J; Zolin, L; Zong, X

    2008-01-01

    A comprehensive survey of event-by-event fluctuations of charged hadron multiplicity in relativistic heavy ions is presented. The survey covers Au+Au collisions at sqrt(s_NN) = 62.4 and 200 GeV, and Cu+Cu collisions sqrt(s_NN) = 22.5, 62.4, and 200 GeV. Fluctuations are measured as a function of collision centrality, transverse momentum range, and charge sign. After correcting for non-dynamical fluctuations due to fluctuations in the collision geometry within a centrality bin, the remaining dynamical fluctuations expressed as the variance normalized by the mean tend to decrease with increasing centrality. The dynamical fluctuations are consistent with or below the expectation from a superposition of participant nucleon-nucleon collisions based upon p+p data, indicating that this dataset does not exhibit evidence of critical behavior in terms of the compressibility of the system. An analysis of Negative Binomial Distribution fits to the multiplicity distributions demonstrates that the heavy ion data exhibit we...

  6. Atom probe tomography simulations and density functional theory calculations of bonding energies in Cu3Au

    KAUST Repository

    Boll, Torben

    2012-10-01

    In this article the Cu-Au binding energy in Cu3Au is determined by comparing experimental atom probe tomography (APT) results to simulations. The resulting bonding energy is supported by density functional theory calculations. The APT simulations are based on the Müller-Schottky equation, which is modified to include different atomic neighborhoods and their characteristic bonds. The local environment is considered up to the fifth next nearest neighbors. To compare the experimental with simulated APT data, the AtomVicinity algorithm, which provides statistical information about the positions of the neighboring atoms, is applied. The quality of this information is influenced by the field evaporation behavior of the different species, which is connected to the bonding energies. © Microscopy Society of America 2012.

  7. Aqueous copper-mediated living polymerization: exploiting rapid disproportionation of CuBr with Me6TREN.

    Science.gov (United States)

    Zhang, Qiang; Wilson, Paul; Li, Zaidong; McHale, Ronan; Godfrey, Jamie; Anastasaki, Athina; Waldron, Christopher; Haddleton, David M

    2013-05-15

    A new approach to perform single-electron transfer living radical polymerization (SET-LRP) in water is described. The key step in this process is to allow full disproportionation of CuBr/Me6TREN (TREN = tris(dimethylamino)ethyl amine to Cu(0) powder and CuBr2 in water prior to addition of both monomer and initiator. This provides an extremely powerful tool for the synthesis of functional water-soluble polymers with controlled chain length and narrow molecular weight distributions (polydispersity index approximately 1.10), including poly(N-isopropylacrylamide), N,N-dimethylacrylamide, poly(ethylene glycol) acrylate, 2-hydroxyethyl acrylate (HEA), and an acrylamido glyco monomer. The polymerizations are performed at or below ambient temperature with quantitative conversions attained in minutes. Polymers have high chain end fidelity capable of undergoing chain extensions to full conversion or multiblock copolymerization via iterative monomer addition after full conversion. Activator generated by electron transfer atom transfer radical polymerization of N-isopropylacrylamide in water was also conducted as a comparison with the SET-LRP system. This shows that the addition sequence of l-ascorbic acid is crucial in determining the onset of disproportionation, or otherwise. Finally, this robust technique was applied to polymerizations under biologically relevant conditions (PBS buffer) and a complex ethanol/water mixture (tequila).

  8. Synthesis, crystal structures, and photoluminescent properties of the Cu(I)/X/alpha,omega-bis(benzotriazole)alkane hybrid family (X = Cl, Br, I, and CN).

    Science.gov (United States)

    Hu, Man-Cheng; Wang, Yan; Zhai, Quan-Guo; Li, Shu-Ni; Jiang, Yu-Cheng; Zhang, Yong

    2009-02-16

    This work focused on a systematic investigation of the influences of the spacer length of the flexible alpha,omega-bis(benzotriazole)alkane ligands and counteranions on the overall molecular architectures of hybrid structures that include Cu(I). Using the self-assembly of CuX (X = Cl, Br, I, or CN) with the five structurally related flexible organic ligands (L1-L5) under hydro(solvo)thermal conditions, we have synthesized and characterized 10 structurally unique materials of the Cu(I)/X/alpha,omega-bis(benzotriazole)alkane organic-inorganic hybrid family, {[CuCl](2)(L1)}(n) (1), {[CuBr](L2)}(n) (2), {[CuCl](2)(L3)}(n) (3), {[CuI](2)(L4)}(n) (4), {[CuBr](2)(L4)}(n) (5), {[CuBr](3)(L5)}(n) (6), {[CuCN](2)(L1)}(n) (7), {[CuCl](4)(L2)}(n) (8), {[CuBr](4)(L2)}(n) (9), and {[CuCl](2)(L4)}(n) (10), by means of elemental analyses, X-ray powder diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and photoluminescence measurements. Single-crystal X-ray analyses showed that the inorganic subunits in these compounds were {Cu(2)X(2)} binuclear clusters (1 and 2), {Cu(4)X(4)} cubane clusters (4, 5, and 10), {CuX}(n) single chains (3 and 7), a {Cu(3)X(3)}(n) ladderlike chain (6), and unprecedented {Cu(8)X(8)}(n) ribbons (8 and 9). The increasing dimensionality from 1-D (1-4) to 2-D (5 and 6) to 3-D (7-10) indicates that the spacer length and isomerism of the bis(benzotriazole)alkane ligands play an essential role in the formation of the framework of the Cu(I) hybrid materials. The influence of counteranions and pi-pi stacking interactions on the formation and dimensionality of these hybrid coordination polymers has also been explored. In addition, all the complexes exhibit high thermal stability and strong fluorescence properties in the solid state at ambient temperature.

  9. Molecular dynamics simulation of Cu/Au thin films under temperature gradient

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qibin, E-mail: qibinli@cqu.edu.cn [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030 (China); Chongqing Key Laboratory of Heterogeneous Material Mechanics, Chongqing University, Chongqing 400030 (China); Peng, Xianghe [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030 (China); Peng, Tiefeng, E-mail: pengtiefeng@cqu.edu.cn [State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030 (China); Tang, Qizhong [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); Zhang, Xiaomin [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); Chongqing Key Laboratory of Heterogeneous Material Mechanics, Chongqing University, Chongqing 400030 (China); Huang, Cheng [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China)

    2015-12-01

    Graphical abstract: Heat transportation in the thin films. - Highlights: • The coherent lattice interface is found at thin films after annealing. • The vacancies are observed clearly in the deposit thin films. • The defect and component will influence the energy transportation in the coatings. • The vacancies and lattice mismatch can enlarge the mobility of atoms. • The phonon transportation in thin films has no apparent rule. - Abstract: Three modulation period thin films, 1.8 nm Cu/3.6 nm Au, 2.7 nm Cu/2.7 nm Au and 3.6 nm Cu/1.8 nm Au, are obtained from deposition method and ideal modeling based on lattice constant, to examine their structures and thermophysical characteristics under temperature gradient. The coherent lattice interface is found both at deposit and ideal thin films after annealing. Also, the vacancies are observed clearly in the deposit thin films. The defect and component of thin films will influence the energy transportation in the coatings. The vacancies and lattice mismatch can enlarge the mobility of atoms and result in the failure of coating under the thermal stress. The power spectrum of atoms’ movement has no apparent rule for phonon transportation in thin films. The results are helpful to reveal the micro-mechanism and provide reasonable basis for the failure of metallic coatings.

  10. Latest results of charged hadron flow measurements in CuAu collisions at RHIC-PHENIX

    Science.gov (United States)

    Nakagomi, Hiroshi

    2016-08-01

    Measurements of azimuthal anisotropic flow vn for inclusive charged hadrons and identified particles at mid rapidity in Cu+Au collisions at √sNN = 200GeV are presented. The data were recorded by the PHENIX experiment at Relativistic Heavy Ion Collider(RHIC). Directed, elliptic and triangular flow as a function of transverse momentum pT are measured with respect to event planes. The inclusive charged hadron vi shows the negative value at high pT. The v2 and v3 are compared to those in Au+Au and Cu+Cu collisions. We find the v 2 and v3 follow an empirical scaling with 1/(ɛnN1/3 part). We also compare the v2 and v3 to hydrodynamical predictions. The identified particles v2 and v3 show a mass ordering in low pT region and baryon and meson splitting in high pT region. However the identified hadron v1 only shows mass ordering in mid pT region.

  11. New Stable Crystal Structures for Cu-Au and Ni-Pt Alloy Systems

    Science.gov (United States)

    Sanati, Mahdi; Wang, L. G.; Zunger, A.

    2003-10-01

    Cu-Au and Ni-Pt are among the best studied fcc alloy systems, exhibiting the famous L10 (AB) and L12 (A_3B) phases. We were wondering if a complete configurational search of the T=0 LDA total energies would reveal any unexpected phases. Total-energy calculations of ˜ 30 arbitrarily chosen structures were used to construct a generalized (momentum-space) Ising Hamiltonian containing ˜ 20 pair-interactions, ˜ 5-10 many-body terms, as well as the long-range strain term. This Hamiltonian was tested carefully as to its ability to predict the LDA energies of other structures. We searched the energies of all fcc configurations with 20 or less atoms per primitive cell ( ˜ 2,700,000 structures), found known L1_0, L12 as well as new, unsuspected structures. The new ground state structures are NiPt_7, Cu_2Au, and Cu_2Au_3. We also found a composition range in which there is quasicontinuum of stable, ordered structures made of (001) repeat units of simple structural motifs. This structural adaptivity is explained in terms of anisotropic, long-range strain energy.

  12. Developing an aqueous approach for synthesizing Au and M@Au (M = Pd, CuPt) hybrid nanostars with plasmonic properties

    CERN Document Server

    Du, Jingshan; Xiong, Yalin; Lin, Zhuoqing; Zhang, Hui; Yang, Deren

    2014-01-01

    Anisotropic Au nanoparticles show unique localized surface plasmon resonance (LSPR) properties, which make it attractive in optical, sensing, and biomedical applications. In this contribution, we report a general and facile strategy towards aqueous synthesis of Au and M@Au (M = Pd, CuPt) hybrid nanostars by reducing HAuCl4 with ethanolamine in the presence of cetyltrimethylammonium bromide (CTAB). According to electron microscopic observation and spectral monitoring, we found that the layered epitaxial growth mode (i.e., Frank-van der Merwe mechanism) contributes to the enlargement of the core, while, the random attachment of Au nanoclusters onto the cores accounts for the formation of the branches. Both of them are indispensable for the formation of the nanostars. The LSPR properties of the Au nanoparticles have been well investigated with morphology control via precursor amount and growth temperature. The Au nanostars showed improved surface-enhanced Raman spectroscopy (SERS) performance for rhodamine 6G du...

  13. The association between content of the elements S, Cl, K, Fe, Cu, Zn and Br in normal and cirrhotic liver tissue from Danes and Greenlandic Inuit examined by dual hierarchical clustering analysis

    DEFF Research Database (Denmark)

    Laursen, Jens; Milman, Nils; Pind, N.

    2014-01-01

    PROJECT: Meta-analysis of previous studies evaluating associations between content of elements sulphur (S), chlorine (Cl), potassium (K), iron (Fe), copper (Cu), zinc (Zn) and bromine (Br) in normal and cirrhotic autopsy liver tissue samples. PROCEDURE: Normal liver samples from 45 Greenlandic......, Br and Zn; Cl with S and Br; K with S, Br and Zn; Cu with Br. Zn with S and K. Br with S, Cl, K and Cu. Fe did not show significant associations with any other element. CONCLUSIONS: In contrast to simple statistical methods, which analyses content of elements separately one by one, dual hierarchical...

  14. Microstructural and electrical properties of Al/n-type Si Schottky diodes with Au-CuPc nanocomposite films as interlayer

    Science.gov (United States)

    Reddy, P. R. Sekhar; Janardhanam, V.; Jyothi, I.; Chang, Han-Soo; Lee, Sung-Nam; Lee, Myung Sun; Reddy, V. Rajagopal; Choi, Chel-Jong

    2017-11-01

    Au-CuPc nanocomposite films were prepared by simultaneous evaporation of Au and CuPc with various Au and CuPc concentrations. Microstructural analysis of Au-CuPc films revealed elongated Au cluster formation from isolated Au nanoclusters with increasing Au concentration associated with coalescence of Au clusters. Au-CuPc films with different compositions were employed as interlayer in Al/n-Si Schottky diode. Barrier height and series resistance of the Al/n-Si Schottky diode with Au-CuPc interlayer decreased with increasing Au concentration. This could be associated with the enhancement of electron tunneling between neighboring clusters due to decrease in spacing of Au clusters and formation of conducting paths through the composite material. Interface state density of the Al/n-Si Schottky diode with Au-CuPc interlayer increased with increasing Au concentration. This might be because the inclusion of metal decreases the crystallinity and crystal size of the polymer matrix accompanied by the formation of local defect sites at the places of metal nucleation.

  15. La réélection de Lula et la Gauche au Brésil

    Directory of Open Access Journals (Sweden)

    Adilar Cigolini

    2007-06-01

    Full Text Available Contrairement aux prévisions, Lula fut massivement réélu en 2006 avec l’appui des populations les plus défavorisées pour lesquelles il a mis en œuvre des mesures sociales notamment contre la faim, la discrimination ethnique ou la violence envers les femmes. Dans son premier mandat, il a promu l’action de l’Etat en instaurant la démocratie participative sur les thèmes de la santé, l’éducation, l’aménagement, l’environnement ou les droits de l’Homme, à laquelle les classes moyennes ont aussi adhéré. Grâce à sa personnalité charismatique et à son origine modeste, le peuple a le sentiment d’être représenté et s’identifie à lui. Economiquement parlant, il a néanmoins maintenu les grandes orientations du gouvernement précédent et par le biais de la négociation, il a renforcé le rôle régional (MERCOSUD et international du Brésil. Ceci montre qu’en Amérique Latine, les politiciens doivent désormais compter avec le peuple pour gouverner.Contrary to the forecasts, Lula was massively re-elected in 2006 with the support of the most underprivileged populations for which it implemented social measures in particular against the hunger, ethnic discrimination or violence towards the women. In its first mandate, it promoted the action of the State by founding the participative democracy on the topics of health, education, installation, the environment or the human rights, which the middle class also appreciated. Thanks to his charismatic personality and his modest origin, the people feel represented and is identified with him. Economically speaking, it nevertheless maintained the main trends of the preceding government and by the means of the negotiation, it reinforced the international and regional role (MERCOSUD of Brazil. This shows that in Latin America, the politicians must from now on take into account the people to govern.

  16. SERS study of surface plasmon resonance induced carrier movement in Au@Cu2O core-shell nanoparticles

    Science.gov (United States)

    Chen, Lei; Zhang, Fan; Deng, Xin-Yu; Xue, Xiangxin; Wang, Li; Sun, Yantao; Feng, Jing-Dong; Zhang, Yongjun; Wang, Yaxin; Jung, Young Mee

    2018-01-01

    A plasmon induced carrier movement enhanced mechanism of surface-enhanced Raman scattering (SERS) was investigated using a charge-transfer (CT) enhancement mechanism. Here, we designed a strategy to study SERS in Au@Cu2O nanoshell nanoparticles with different shell thicknesses. Among the plasmonically coupled nanostructures, Au spheres with Cu2O shells have been of special interest due to their ultrastrong electromagnetic fields and controllable carrier transfer properties, which are useful for SERS. Au@Cu2O nanoshell nanoparticles (NPs) with shell thicknesses of 48-56 nm are synthesized that exhibit high SERS activity. This high activity originates from plasmonic-induced carrier transfer from Au@Cu2O to 4-mercaptobenzoic acid (MBA). The CT transition from the valence band (VB) of Cu2O to the second excited π-π* transition of MBA, and is of b2 electronic symmetry, which was enhanced significantly. The Herzberg-Teller selection rules were employed to predict the observed enhanced b2 symmetry modes. The system constructed in this study combines the long-range electromagnetic effect of Au NPs, localized surface plasmon resonance (LSPR) of the Au@Cu2O nanoshell, and the CT contribution to assist in understanding the SERS mechanism based on LSPR-induced carrier movement in metal/semiconductor nanocomposites.

  17. Critères de gravité des brûlures: à propos de 337 cas de brûlés au ...

    African Journals Online (AJOL)

    L'objectif était d'étudier les critères de gravité des brûlures chez des patients brûlés hospitalisés à l'hôpital militaire d'instruction Mohamed V de Rabat. Il s'agit d'une étude rétrospective qui concernait 337 patients hospitalisés de 2004 à 2010. Les variables étudiés sont: l'âge, la surface corporelle brûlée, la profondeur, ...

  18. Reaction mechanisms of CO oxidation on cationic, neutral, and anionic X-O-Cu (X = Au, Ag) clusters

    Science.gov (United States)

    Zhang, Yan; He, Xiao

    2017-10-01

    We performed extensive DFT calculations for the microscopic mechanism of CO oxidation on cationic, neutral and anionic X-O-Cu (X = Au, Ag) clusters. We obtained following findings. First, the reaction mechanism of neutral X-O-Cu (X = Au, Ag) to the CO follows the Eley-Rideal-like (ER) mechanism and Langmuir-Hinshelwood-like (LH) mechanism. Second, as compared to the pure Au clusters, new reaction pathways have been found via a Langmuir-Hinshelwood-like (LH) mechanism. The oxidation of CO on cationic Au-O-Cu in nature follows an Eley-Rideal-like (ER) mechanism. Third, comparing with their reaction profiles between cationic, neutral and anionic Au-O-Cu and CO, all the reactions on Ag-O-Cu can occur more easily. Furthermore, the selectivity of the oxidation of CO on Ag-O-Cu will be improved. On the basis of our calculations, we suggest that AgCu may also be a good catalyst due to its high oxidation performance.

  19. Cu-Au alloy nanostructures coated with aptamers: a simple, stable and highly effective platform for in vivo cancer theranostics

    Science.gov (United States)

    Ye, Xiaosheng; Shi, Hui; He, Xiaoxiao; Yu, Yanru; He, Dinggeng; Tang, Jinlu; Lei, Yanli; Wang, Kemin

    2016-01-01

    As a star material in cancer theranostics, photoresponsive gold (Au) nanostructures may still have drawbacks, such as low thermal conductivity, irradiation-induced melting effect and high cost. To solve the problem, copper (Cu) with a much higher thermal conductivity and lower cost was introduced to generate a novel Cu-Au alloy nanostructure produced by a simple, gentle and one-pot synthetic method. Having the good qualities of both Cu and Au, the irregularly-shaped Cu-Au alloy nanostructures showed several advantages over traditional Au nanorods, including a broad and intense near-infrared (NIR) absorption band from 400 to 1100 nm, an excellent heating performance under laser irradiation at different wavelengths and even a notable photostability against melting. Then, via a simple conjugation of fluorophore-labeled aptamers on the Cu-Au alloy nanostructures, active targeting and signal output were simultaneously introduced, thus constructing a theranostic platform based on fluorophore-labeled, aptamer-coated Cu-Au alloy nanostructures. By using human leukemia CCRF-CEM cancer and Cy5-labeled aptamer Sgc8c (Cy5-Sgc8c) as the model, a selective fluorescence imaging and NIR photothermal therapy was successfully realized for both in vitro cancer cells and in vivo tumor tissues. It was revealed that Cy5-Sgc8c-coated Cu-Au alloy nanostructures were not only capable of robust target recognition and stable signal output for molecular imaging in complex biological systems, but also killed target cancer cells in mice with only five minutes of 980 nm irradiation. The platform was found to be simple, stable, biocompatible and highly effective, and shows great potential as a versatile tool for cancer theranostics.As a star material in cancer theranostics, photoresponsive gold (Au) nanostructures may still have drawbacks, such as low thermal conductivity, irradiation-induced melting effect and high cost. To solve the problem, copper (Cu) with a much higher thermal conductivity

  20. Facile one-pot synthesis of luminescent-thiolated Au nanocluster and Au(I)-thiolate complexes as highly selective Cu2+ probes

    Science.gov (United States)

    Pal, Nabin Kumar; Kryschi, Carola

    2015-05-01

    Here in this paper, we reported of a facile photo-induced one-step method for synthesizing highly luminescent Au(I)-thiolate complexes (size 2-3 nm) and thiolated Au nanocluster (AuNC, size 1.6 nm). The hydrophilic thiol being 3-mercaptopropanoic acid (3-MPA) was used as stabilizing agent. The as-prepared Au(I)-thiolate complexes exhibit bright red photoluminescence (PL) and were used as an efficient sensor for the selective detection of Cu2+ ions. We also observed the formation of thiol-stabilized Au nanoparticles through continuous electron beam irradiation of Au(I)-thiolated complexes. The Au(I)-thiolate complexes show a PL lifetime on the μs time scale, whereas the PL lifetime of the thiolated AuNC is on the ns time scales. The photo-physical, electronic, structural and morphological properties of the thiolated AuNC and Au(I)-thiolate complexes were examined upon performing UV-Vis absorption spectroscopy, stationary and time-resolved PL spectroscopy, X-ray photoelectron spectroscopy, femtosecond transient absorption spectroscopy and transmission electron microscopy experiments.

  1. Facile one-pot synthesis of luminescent-thiolated Au nanocluster and Au(I)–thiolate complexes as highly selective Cu{sup 2+} probes

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Nabin Kumar; Kryschi, Carola, E-mail: carola.kryschi@fau.de [Friedrich-Alexander University of Erlangen-Nuremberg, Department of Chemistry and Pharmacy and ICMM (Germany)

    2015-05-15

    Here in this paper, we reported of a facile photo-induced one-step method for synthesizing highly luminescent Au(I)–thiolate complexes (size ∼2–3 nm) and thiolated Au nanocluster (AuNC, size ∼1.6 nm). The hydrophilic thiol being 3-mercaptopropanoic acid (3-MPA) was used as stabilizing agent. The as-prepared Au(I)–thiolate complexes exhibit bright red photoluminescence (PL) and were used as an efficient sensor for the selective detection of Cu{sup 2+} ions. We also observed the formation of thiol-stabilized Au nanoparticles through continuous electron beam irradiation of Au(I)–thiolated complexes. The Au(I)–thiolate complexes show a PL lifetime on the μs time scale, whereas the PL lifetime of the thiolated AuNC is on the ns time scales. The photo-physical, electronic, structural and morphological properties of the thiolated AuNC and Au(I)–thiolate complexes were examined upon performing UV–Vis absorption spectroscopy, stationary and time-resolved PL spectroscopy, X-ray photoelectron spectroscopy, femtosecond transient absorption spectroscopy and transmission electron microscopy experiments.

  2. Effect of cascade remnants on freely migrating defects in Cu-1% Au alloys

    Energy Technology Data Exchange (ETDEWEB)

    Iwase, A.; Rehn, L.E.; Baldo, P.M.; Funk, L. [Argonne National Lab., IL (United States). Materials Science Div.

    1997-03-01

    The effects of cascade remnants on Freely Migrating Defects (FMD) were studied by measuring Radiation-Induced Segregation (RIS) in Cu-1%Au at 400degC during simultaneous irradiation with 1.5-MeV He and (400-800)-keV heavy ions (Ne, Ar or Cu). The large RIS observed during 1.5-MeV He-only irradiation was dramatically suppressed under simultaneous heavy ion irradiation. For Cu simultaneous irradiation, the suppression disappeared immediately after the Cu irradiation ceased, while for simultaneous inert gas (Ne or Ar) irradiation, the suppression persisted after the ion beam was turned off. These results demonstrate that the displacement cascades created by heavy ions introduce additional annihilation sites, which reduce the steady-state FMD concentrations. As the cascade remnants produced by Cu ions are thermally unstable at 400degC, the RIS suppression occurs only during simultaneous irradiation. On the other hand, the inert gas atoms which accumulate in the specimen apparently stabilize the cascade remnants, allowing the suppression to persist. (author)

  3. Co-Cu-Au deposits in metasedimentary rocks-A preliminary report

    Science.gov (United States)

    Slack, J.F.; Causey, J.D.; Eppinger, R.G.; Gray, J.E.; Johnson, C.A.; Lund, K.I.; Schulz, K.J.

    2010-01-01

    A compilation of data on global Co-Cu-Au deposits in metasedimentary rocks refines previous descriptive models for their occurrence and provides important information for mineral resource assessments and exploration programs. This compilation forms the basis for a new classification of such deposits, which is speculative at this early stage of research. As defined herein, the Co-Cu-Au deposits contain 0.1 percent or more by weight of Co in ore or mineralized rock, comprising disseminated to semi-massive Co-bearing sulfide minerals with associated Fe- and Cu-bearing sulfides, and local gold, concentrated predominantly within rift-related, siliciclastic metasedimentary rocks of Proterozoic age. Some deposits have appreciable Ag ? Bi ? W ? Ni ? Y ? rare earth elements ? U. Deposit geometry includes stratabound and stratiform layers, lenses, and veins, and (or) discordant veins and breccias. The geometry of most deposits is controlled by stratigraphic layering, folds, axial-plane cleavage, shear zones, breccias, or faults. Ore minerals are mainly cobaltite, skutterudite, glaucodot, and chalcopyrite, with minor gold, arsenopyrite, pyrite, pyrrhotite, bismuthinite, and bismuth; some deposits have appreciable tetrahedrite, uraninite, monazite, allanite, xenotime, apatite, scheelite, or molybdenite. Magnetite can be abundant in breccias, veins, or stratabound lenses within ore or surrounding country rocks. Common gangue minerals include quartz, biotite, muscovite, K-feldspar, albite, chlorite, and scapolite; many deposits contain minor to major amounts of tourmaline. Altered wall rocks generally have abundant biotite or albite. Mesoproterozoic metasedimentary successions constitute the predominant geologic setting. Felsic and (or) mafic plutons are spatially associated with many deposits and at some localities may be contemporaneous with, and involved in, ore formation. Geoenvironmental data for the Blackbird mining district in central Idaho indicate that weathering of

  4. Engineering the Composition and Structure of Bimetallic Au-Cu Alloy Nanoparticles in Carbon Nanofibers: Self-Supported Electrode Materials for Electrocatalytic Water Splitting.

    Science.gov (United States)

    Wang, Juan; Zhu, Han; Yu, Danni; Chen, JiaWei; Chen, JiaDong; Zhang, Ming; Wang, LiNa; Du, MingLiang

    2017-06-14

    The bimetallic Au-Cu alloy nanoparticles have been constructed in electrospun carbon nanofibers (Au-Cu/CNFs), employing as high efficient hydrogen evolution reaction (HER) electrode. The morphology, structure, and composition of bimetallic Au-Cu alloy can be controlled by adjusting the precursor nanofibers through a facile approach. With the increased Cu content, the Au-Cu alloy have a transition from the homogeneous AuCu3 alloy phase to the Au3Cu phase with Cu shell. The self-supported bimetallic Au-Cu/CNFs hybrid can be directly employed as electrode materials for water splitting, and it showed excellent electrochemical activity, including long-term stability, high exchange current density, and low overpotential. The outstanding HER performance could be mainly attributed to the synergistic interactions and interfacial effects of Au-Cu alloy with high densities of uncoordinated surface atoms. In addition, the fast charge transport and the fast kinetic for the desorption of the gas were originated from the self-supported three-dimensional architectures consist of integrated Au-Cu/CNFs networks. The Au-Cu/CNFs with mass ratio of 1:2 (Au3Cu-Cu "core-shell" alloy) obtain the lowest overpotential of 83 mV (at j = 10 mA cm(-2)), lowest Tafel slope of 70 mV dec(-1), and highest exchange current density of 0.790 mA cm(-2). The present investigations offer a new strategy for the design and synthesis of unique nanocrystals in energy conversion related application.

  5. Icosahedral Pt-centered Pt13 and Pt19 carbonyl clusters decorated by [Cd5(μ-Br)5Br(5-x)(solvent)x]x+ rings reminiscent of the decoration of Au-Fe-CO and Au-thiolate nanoclusters: a unifying approach to their electron counts.

    Science.gov (United States)

    Femoni, Cristina; Iapalucci, Maria Carmela; Longoni, Giuliano; Zacchini, Stefano; Zarra, Salvatore

    2011-03-02

    The new [Pt(13)(CO)(12){Cd(5)(μ-Br)(5)Br(2)(dmf)(3)}(2)](2-) and [Pt(19)(CO)(17){Cd(5)(μ-Br)(5)Br(3)(Me(2)CO)(2)}{Cd(5)(μ-Br)(5)Br(Me(2)CO)(4)}](2-) clusters have been obtained in good yields by reaction of [Pt(12)(CO)(24)](2-) with CdBr(2)·H(2)O in dmf at 90 °C and structurally characterized by X-ray diffraction. Their structures consist of a Pt-centered Pt(13)(CO)(12) icosahedron and a Pt(19)(CO)(17) interpenetrated double icosahedron, respectively, decorated by two Cd(5)(μ-Br)(5)Br(5-x)(solvent)(x) rings. Their surface decoration may be related to that of Au-Fe-CO clusters as well as to the staple motifs stabilizing gold-thiolates nanoclusters. An oversimplified and unifying approach to interpret their electron count is suggested.

  6. Phobos results on charged particle multiplicity and pseudorapidity distributions in Au+Au, Cu+Cu, d+Au, and p+p collisions at ultra-relativistic energies

    CERN Document Server

    Alver, B; Baker, M D; Ballintijn, M; Barton, D S; Betts, R R; Bickley, A A; Bindel, R; Budzanowski, A; Busza, W; Carroll, A; Chai, Z; Chetluru, V; Decowski, M P; Garcıa, E; Gburek, T; George, N; Gulbrandsen, K; Gushue, S; Halliwell, C; Hamblen, J; Heintzelman, G A; Henderson, C; Hofman, D J; Hollis, R S; Holynski, R; Holzman, B; Iordanova, A; Johnson, E; Kane, J L; Katzy, J; Khan, N; Kucewicz, J Kotula W; Kulinich, P; Kuo, C M; Li, W; Lin, W T; Loizides, C; Manly, S; McLeod, D; Michalowski, J; Mignerey, A C; Nouicer, R; Olszewski, A; Pak, R; Park, I C; Pernegger, H; Reed, C; Remsberg, L P; Reuter, M; Roland, C; Roland, G; Rosenberg, L; Sagerer, J; Sarin, P; Sawicki, P; Sedykh, I; Skulski, W; Smith, C E; Steadman, S G; Steinberg, P; Stephans, G S F; Stodulski, M; Sukhanov, A; Tonjes, M B; Trzupek, A; Vale, C; van Nieuwenhuizen, G J; Vaurynovich, S S; Verdier, R; Veres, G I; Wadsworth, B; Walters, P; Wenger, E; Wolfs, F L H; Wosiek, B; Wozniak, K; Wuosmaa, A H; Wyslouch, B

    2010-01-01

    Pseudorapidity distributions of charged particles emitted in $Au+Au$, $Cu+Cu$, $d+Au$, and $p+p$ collisions over a wide energy range have been measured using the PHOBOS detector at RHIC. The centrality dependence of both the charged particle distributions and the multiplicity at midrapidity were measured. Pseudorapidity distributions of charged particles emitted with $|\\eta|<5.4$, which account for between 95% and 99% of the total charged-particle emission associated with collision participants, are presented for different collision centralities. Both the midrapidity density, $dN_{ch}/d\\eta$, and the total charged-particle multiplicity, $N_{ch}$, are found to factorize into a product of independent functions of collision energy, $\\sqrt{s_{_{NN}}}$, and centrality given in terms of the number of nucleons participating in the collision, $N_{part}$. The total charged particle multiplicity, observed in these experiments and those at lower energies, assumes a linear dependence of $(\\ln s_{_{NN}})^2$ over the fu...

  7. Nuclear matter effects on $J/\\psi$ production in asymmetric Cu+Au collisions at $\\sqrt{s_{_{NN}}}$ = 200 GeV

    CERN Document Server

    Aidala, C; Akiba, Y; Akimoto, R; Alexander, J; Aoki, K; Apadula, N; Asano, H; Atomssa, E T; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Bai, X; Bannier, B; Barish, K N; Bathe, S; Baublis, V; Baumann, C; Baumgart, S; Bazilevsky, A; Beaumier, M; Belmont, R; Berdnikov, A; Berdnikov, Y; Bing, X; Black, D; Blau, D S; Bok, J; Boyle, K; Brooks, M L; Bryslawskyj, J; Buesching, H; Bumazhnov, V; Butsyk, S; Campbell, S; Chen, C -H; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choi, S; Christiansen, P; Chujo, T; Cianciolo, V; Cole, B A; Cronin, N; Crossette, N; Csanád, M; Csörgő, T; Datta, A; Daugherity, M S; David, G; Dehmelt, K; Denisov, A; Deshpande, A; Desmond, E J; Ding, L; Do, J H; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; D'Orazio, L; Engelmore, T; Enokizono, A; Esumi, S; Eyser, K O; Fadem, B; Fields, D E; Finger, M; Finger,, M; Fleuret, F; Fokin, S L; Frantz, J E; Franz, A; Frawley, A D; Fukao, Y; Gainey, K; Gal, C; Garg, P; Garishvili, A; Garishvili, I; Giordano, F; Glenn, A; Gong, X; Gonin, M; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Perdekamp, M Grosse; Gu, Y; Gunji, T; Guragain, H; Haggerty, J S; Hahn, K I; Hamagaki, H; Hanks, J; Hashimoto, K; Hayano, R; He, X; Hemmick, T K; Hester, T; Hill, J C; Hollis, R S; Homma, K; Hong, B; Hoshino, T; Huang, J; Huang, S; Ichihara, T; Ikeda, Y; Imai, K; Imazu, Y; Inaba, M; Iordanova, A; Isenhower, D; Isinhue, A; Ivanishchev, D; Jacak, B V; Jeon, S J; Jezghani, M; Jia, J; Jiang, X; Johnson, B M; Joo, K S; Jouan, D; Jumper, D S; Kamin, J; Kanda, S; Kang, B H; Kang, J H; Kang, J S; Kapustinsky, J; Kawall, D; Kazantsev, A V; Key, J A; Khachatryan, V; Khandai, P K; Khanzadeev, A; Kijima, K M; Kim, C; Kim, D J; Kim, E -J; Kim, Y -J; Kim, Y K; Kistenev, E; Klatsky, J; Kleinjan, D; Kline, P; Koblesky, T; Kofarago, M; Komkov, B; Koster, J; Kotchetkov, D; Kotov, D; Krizek, F; Kurita, K; Kurosawa, M; Kwon, Y; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, D M; Lee, G H; Lee, J; Lee, K B; Lee, K S; Lee, S H; Leitch, M J; Leitgab, M; Lewis, B; Li, X; Lim, S H; Liu, M X; Lynch, D; Maguire, C F; Makdisi, Y I; Makek, M; Manion, A; Manko, V I; Mannel, E; Maruyama, T; McCumber, M; McGaughey, P L; McGlinchey, D; McKinney, C; Meles, A; Mendoza, M; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Milov, A; Mishra, D K; Mitchell, J T; Miyasaka, S; Mizuno, S; Mohanty, A K; Morrison, D P; Moskowitz, M; Moukhanova, T V; Murakami, T; Murata, J; Nagae, T; Nagamiya, S; Nagle, J L; Nagy, M I; Nakagawa, I; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nattrass, C; Netrakanti, P K; Nihashi, M; Niida, T; Nouicer, R; Novak, T; Novitzky, N; Nyanin, A S; O'Brien, E; Ogilvie, C A; Oide, H; Okada, K; Oskarsson, A; Ozawa, K; Pak, R; Pantuev, V; Papavassiliou, V; Park, I H; Park, S; Park, S K; Pate, S F; Patel, L; Peng, J -C; Perepelitsa, D; Perera, G D N; Peressounko, D Yu; Perry, J; Petti, R; Pinkenburg, C; Pisani, R P; Purschke, M L; Qu, H; Rak, J; Ravinovich, I; Read, K F; Reynolds, D; Riabov, V; Riabov, Y; Richardson, E; Riveli, N; Roach, D; Rolnick, S D; Rosati, M; Ryu, M S; Sahlmueller, B; Saito, N; Sakaguchi, T; Sako, H; Samsonov, V; Sarsour, M; Sato, S; Sawada, S; Sedgwick, K; Seele, J; Seidl, R; Sekiguchi, Y; Sen, A; Seto, R; Sett, P; Sharma, D; Shaver, A; Shein, I; Shibata, T -A; Shigaki, K; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Singh, B K; Singh, C P; Singh, V; Skolnik, M; Slunečka, M; Solano, S; Soltz, R A; Sondheim, W E; Sorensen, S P; Soumya, M; Sourikova, I V; Stankus, P W; Steinberg, P; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Stone, M R; Sugitate, T; Sukhanov, A; Sun, J; Takahara, A; Taketani, A; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tennant, E; Timilsina, A; Todoroki, T; Tomášek, M; Torii, H; Towell, R S; Tserruya, I; van Hecke, H W; Vargyas, M; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Virius, M; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Whitaker, S; Wolin, S; Woody, C L; Wysocki, M; Yamaguchi, Y L; Yanovich, A; Yokkaichi, S; Yoon, I; You, Z; Younus, I; Yushmanov, I E; Zajc, W A; Zelenski, A; Zhou, S

    2014-01-01

    We report on $J/\\psi$ production from asymmetric Cu+Au heavy-ion collisions at $\\sqrt{s_{_{NN}}}$=200 GeV at the Relativistic Heavy Ion Collider at both forward (Cu-going direction) and backward (Au-going direction) rapidities. The nuclear modification of $J/\\psi$ yields in Cu$+$Au collisions in the Au-going direction is found to be comparable to that in Au$+$Au collisions when plotted as a function of the number of participating nucleons. In the Cu-going direction, $J/\\psi$ production shows a stronger suppression. This difference is comparable in magnitude and has the same sign as the difference expected from shadowing effects due to stronger low-$x$ gluon suppression in the larger Au nucleus. The relative suppression is opposite to that expected from hot nuclear matter dissociation, since a higher energy density is expected in the Au-going direction.

  8. Temperature dependence of spin-orbit torques in Cu-Au alloys

    KAUST Repository

    Wen, Yan

    2017-03-07

    We investigated current driven spin-orbit torques in Cu40Au60/Ni80Fe20/Ti layered structures with in-plane magnetization. We have demonstrated a reliable and convenient method to separate dampinglike torque and fieldlike torque by using the second harmonic technique. It is found that the dampinglike torque and fieldlike torque depend on temperature very differently. Dampinglike torque increases with temperature, while fieldlike torque decreases with temperature, which are different from results obtained previously in other material systems. We observed a nearly linear dependence between the spin Hall angle and longitudinal resistivity, suggesting that skew scattering may be the dominant mechanism of spin-orbit torques.

  9. X-ray fluorescence holography studies for a Cu{sub 3}Au crystal

    Energy Technology Data Exchange (ETDEWEB)

    Dąbrowski, K.M., E-mail: karol.dabrowski@uj.edu.pl; Dul, D.T.; Jaworska-Gołąb, T.; Rysz, J.; Korecki, P.

    2015-12-01

    In this work we show that performing a numerical correction for beam attenuation and indirect excitation allows one to fully restore element sensitivity in the three-dimensional reconstruction of the atomic structure. This is exemplified by a comparison of atomic images reconstructed from holograms measured for ordered and disordered phases of a Cu{sub 3}Au crystal that clearly show sensitivity to changes in occupancy of the atomic sites. Moreover, the numerical correction, which is based on quantitative methods of X-ray fluorescence spectroscopy, was extended to take into account the influence of a disturbed overlayer in the sample.

  10. Alloy-dependent deformation behavior of highly ductile nanocrystalline AuCu thin films

    Energy Technology Data Exchange (ETDEWEB)

    Lohmiller, Jochen [Karlsruhe Institute of Technology, Institute for Applied Materials, P.O. Box 3640, 76021 Karlsruhe (Germany); Laboratory for Nanometallurgy, Department of Materials, ETH Zurich, Wolfgang-Pauli-Str. 10, 8093 Zurich (Switzerland); Spolenak, Ralph [Laboratory for Nanometallurgy, Department of Materials, ETH Zurich, Wolfgang-Pauli-Str. 10, 8093 Zurich (Switzerland); Gruber, Patric A., E-mail: patric.gruber@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, P.O. Box 3640, 76021 Karlsruhe (Germany)

    2014-02-10

    Nanocrystalline thin films on compliant substrates become increasingly important for the development of flexible electronic devices. In this study, nanocrystalline AuCu thin films on polyimide substrate were tested in tension while using a synchrotron-based in situ testing technique. Analysis of X-ray diffraction profiles allowed identifying the underlying deformation mechanisms. Initially, elastic and microplastic deformation is observed, followed by dislocation-mediated shear band formation, and eventually macroscopic crack formation. Particularly the influence of alloy composition, heat-treatment, and test temperature were investigated. Generally, a highly ductile behavior is observed. However, high Cu concentrations, annealing, and/or large plastic strains lead to localized deformation and hence reduced ductility. On the other hand, enhanced test temperature allows for a delocalized deformation and extended ductility.

  11. Magmatic controls on the genesis of porphyry Cu-Mo-Au deposits: The Bingham Canyon example

    Science.gov (United States)

    Grondahl, Carter; Zajacz, Zoltán

    2017-12-01

    Bingham Canyon is one of the world's largest porphyry Cu-Mo-Au deposits and was previously used as an example to emphasize the role of magma mixing and magmatic sulphide saturation in the enhancement of ore fertility of magmatic systems. We analyzed whole rocks, minerals, and silicate melt inclusions (SMI) from the co-genetic, ore-contemporaneous volcanic package (∼38 Ma). As opposed to previous propositions, whole-rock trace element signatures preclude shoshonite-latite genesis via mixing of melanephelinite and trachyte or rhyolite, whereas core to rim compositional profiles of large clinopyroxene phenocrysts suggests the amalgamation of the ore-related magma reservoir by episodic recharge of shoshonitic to latitic magmas with various degrees of differentiation. Major and trace element and Sr and Nd isotopic signatures indicate that the ore-related shoshonite-latite series were generated by low-degree partial melting of an ancient metasomatized mantle source yielding volatile and ore metal rich magmas. Latite and SMI compositions can be reproduced by MELTS modeling assuming 2-step lower and upper crustal fractionation of a primary shoshonite with minimal country rock assimilation. High oxygen fugacities (≈ NNO + 1) are prevalent as evidenced by olivine-spinel oxybarometry, high SO3 in apatite, and anhydrite saturation. The magma could therefore carry significantly more S than would have been possible at more reducing conditions, and the extent of ore metal sequestration by magmatic sulphide saturation was minimal. The SMI data show that the latites were Cu rich, with Cu concentrations in the silicate melt reaching up to 300-400 ppm at about 60 wt% SiO2. The Au and Ag concentrations are also high (1.5-4 and 50-200 ppb, respectively), but show less variation with SiO2. A sudden drop in Cu and S concentrations in the silicate melt at around 65 wt% SiO2 in the presence of high Cl, Mo, Ag, and Au shows that the onset of effective metal extraction by fluid

  12. Facet-dependent and au nanocrystal-enhanced electrical and photocatalytic properties of Au-Cu2O core-shell heterostructures.

    Science.gov (United States)

    Kuo, Chun-Hong; Yang, Yu-Chen; Gwo, Shangjr; Huang, Michael H

    2011-02-02

    We report highly facet-dependent electrical properties of Cu(2)O nanocubes and octahedra and significant enhancement of gold nanocrystal cores to the electrical conductivity of Au-Cu(2)O core-shell octahedra. Cu(2)O nanocubes and octahedra and Au-Cu(2)O core-shell cubes and octahedra were synthesized by following our reported facile procedures at room temperature. Two oxide-free tungsten probes attached to a nanomanipulator installed inside a scanning electron microscope made contacts to a single Cu(2)O nanocrystal for the I-V measurements. Pristine Cu(2)O octahedra bounded by {111} facets are 1100 times more conductive than pristine Cu(2)O cubes enclosed by {100} faces, which are barely conductive. Core-shell cubes are only slightly more conductive than pristine cubes. A 10,000-fold increase in conductivity over a cube has been recorded for an octahedron. Remarkably, core-shell octahedra are far more conductive than pristine octahedra. The same facet-dependent electrical behavior can still be observed on a single nanocrystal exposing both {111} and {100} facets. This new fundamental property may be observable in other semiconductor nanocrystals. We also have shown that both core-shell cubes and octahedra outperform pristine cubes and octahedra in the photodegradation of methyl orange. Efficient photoinduced charge separation is attributed to this enhanced photocatalytic activity. Interestingly, facet-selective etching occurred over the {100} corners of some octahedra and core-shell octahedra during photocatalysis. The successful preparation of Au-Cu(2)O core-shell heterostructures with precise shape control has offered opportunities to discover new and exciting physical and chemical properties of nanocrystals.

  13. Penetration Depth and Low Field Vortex Behavior in κ-(ET)_2Cu[N(CN)_2]Br

    Science.gov (United States)

    Giannetta, R.; Carrington, A.; Schlueter, J.; Williams, J. M.

    1997-03-01

    The issue of pairing symmetry in organic superconductors is still controversial. Yip and Sauls(S.K. Yip and J.A. Sauls, Phys. Rev. Lett. 69), 2264 (1992). have suggested that the magnetic field dependence of the penetration depth (λ) in the Meissner state can provide a new test for d-wave symmetry. Motivated by this work, we have studied both the magnetic field and temperature dependence of the penetration depth in single crystal κ-(ET)_2Cu[N(CN)_2]Br. At low temperatures we find that λ ~ T^2 suggesting the presence of nodes in the energy gap. We present data for a variety of field orientations and show that the identification of a Meissner state in this material is itself problematic. This work was supported by NSF Grant # DMR-89-20538 and STCS/NSF DMR 91-20000 and by DoE contract # W-31-109-ENG-38.

  14. A Study of the Influence of Percentage of Copper on the Structural and Optical Properties of Au-Cu Nanoparticle

    Directory of Open Access Journals (Sweden)

    Parivash Mashayekhi Shams

    2016-07-01

    Full Text Available Here we present our experimental results in synthesizing Au-Cu nano-particles with tunable localized surface plasmon resonance frequency through wet-chemical at temperature room. The reaction is performed in the presence of ascorbic acid as a reducing agent and polyvinyl pyrrolidone as capping agent via four different procedures: (1 mixture of 90% HAuCl4 and 10% CuSO4.5H2O precursors, (2 mixture of 75% HAuCl4 and 25% CuSO4.5H2O precursors, (3 mixture of 50% HAuCl4 and 50% CuSO4.5H2O precursors (4 mixture of 25% HAuCl4 and 75% CuSO4.5H2O precursors. Effect of different percentages of Cu on Au nanoparticles has been analyzed using X-ray diffraction (XRD, scanning electron microscopy (SEM with EDAX analysis, DRS UV-Vis, and Fourier transform IR spectra (FTIR analysis. X-ray diffraction (XRD analysis revealed that the nanoparticles are of cubic structure without an impure phase. The successful doping of the Cu into the Au host was evident by XRD line shiftings. The increasing percentage of copper leads to the decreasing grain size. With the increase of Cu2+ to Au3+ ratio in the Cu2+/Au3+ mixed solution (> 50% Cu, XRD lines show no shifting. The average crystal sizes of the particles at room temperature were less than 9.9 nm. The surface plasmon resonance peak shifts from 380 to 340 nm, party due to the change in particle size. SEM images show a spherical shape and the size of nanoparticles becomes smaller with increasing the percentage of copper. Moreover, in the molar ratio of Cu2+/Au3+ = 75/25 (>50% Cu, mixture of spherical and trigonal nanoparticles were prepared. Fourier transform infrared spectroscopy (FT-IR showed the coordination and conjugation nanoparticles with N and O atoms of C-N and C=O bonds.

  15. X-ray luminescence of ZnSCdS:Au,Cu phosphor using X-ray beams for medical applications

    Science.gov (United States)

    Kandarakis, I.; Cavouras, D.; Nomicos, C. D.; Panayiotakis, G. S.

    2001-07-01

    The purpose of the present study was to evaluate the X-ray luminescence and imaging performance of phosphor screens prepared from ZnSCdS:Au,Cu. Absolute efficiency, X-ray luminescence efficiency, detector optical gain, and gain transfer function were experimentally determined. Theoretical models were also employed to fit experimental data and to determine optical properties of the phosphor material. Additionally, the emission spectrum of ZnSCdS:Au,Cu was measured and its compatibility with the spectral sensitivity of radiographic optical detectors (films, photodiodes) was determined. Results showed that ZnSCdS:Au,Cu is an efficient phosphor exhibiting high intrinsic X-ray to light conversion efficiency (0.17) and an excellent spectral compatibility (0.9) with amorphous silicon photodiodes, used in optical detectors of modern digital radiography systems.

  16. A DFT-based genetic algorithm search for AuCu nanoalloy electrocatalysts for CO2 reduction

    DEFF Research Database (Denmark)

    Lysgaard, Steen; Mýrdal, Jón Steinar Garðarsson; Hansen, Heine Anton

    2015-01-01

    with gold atoms having only copper neighbors and a gold surface with a few copper atoms in the terraces. We also present an adsorbate-dependent correction scheme, which enables an accurate determination of adsorption energies using a computationally fast, localized LCAO-basis set. These show......Using a DFT-based genetic algorithm (GA) approach, we have determined the most stable structure and stoichiometry of a 309-atom icosahedral AuCu nanoalloy, for potential use as an electrocatalyst for CO2 reduction. The identified core–shell nano-particle consists of a copper core interspersed....... This shows that the mixed Cu135@Au174 core–shell nanoalloy has a similar adsorption energy, for the most favorable site, as a pure gold nano-particle. Cu, however, has the effect of stabilizing the icosahedral structure because Au particles are easily distorted when adding adsorbates....

  17. Magnetically separable CuFe{sub 2}O{sub 4}/AgBr composite photocatalysts: Preparation, characterization, photocatalytic activity and photocatalytic mechanism under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yalei; Lin, Cuiping; Bi, Huijie; Liu, Yonggang; Yan, Qishe, E-mail: Qisheyanzzu@163.com

    2017-01-15

    Highlights: • CuFe{sub 2}O{sub 4}/AgBr composites were prepared by a facile sol-gel and hydrothermal method. • Visible-light response and high photocatalytic performance. • Excellent magnetic properties. • Different reactive species had different effects on degradation different pollutants. - Abstract: The CuFe{sub 2}O{sub 4} and CuFe{sub 2}O{sub 4}/AgBr composites with different CuFe{sub 2}O{sub 4} contents were prepared by a facile sol-gel and hydrothermal method, respectively. The as-synthesized photocatalysts were characterized by means of powder X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectrum (UV–vis DRS). Their magnetic properties, photocatalytic degradation activities on methyl orange (MO) and tetracycline hydrochloride (TC) solution and photocatalytic mechanism were investigated in detail. The results revealed that the CuFe{sub 2}O{sub 4}/AgBr composites exhibited significantly higher photocatalytic activities than the pure CuFe{sub 2}O{sub 4}. The enhanced photocatalytic activity could be attributed to the matched band structure of two components and more effective charge transportation and separations. In addition, the quenching investigation of different scavengers demonstrated that h{sup +}, ·OH, ·O{sub 2}{sup −} reactive species played different roles in the decolorization of MO and degradation of TC.

  18. ⁶⁴Cu-Doped PdCu@Au Tripods: A Multifunctional Nanomaterial for Positron Emission Tomography and Image-Guided Photothermal Cancer Treatment.

    Science.gov (United States)

    Pang, Bo; Zhao, Yongfeng; Luehmann, Hannah; Yang, Xuan; Detering, Lisa; You, Meng; Zhang, Chao; Zhang, Lei; Li, Zhi-Yuan; Ren, Qiushi; Liu, Yongjian; Xia, Younan

    2016-03-22

    This article reports a facile synthesis of radiolabeled PdCu@Au core-shell tripods for use in positron emission tomography (PET) and image-guided photothermal cancer treatment by directly incorporating radioactive (64)Cu atoms into the crystal lattice. The tripod had a unique morphology determined by the PdCu tripod that served as a template for the coating of Au shell, in addition to well-controlled specific activity and physical dimensions. The Au shell provided the nanostructure with strong absorption in the near-infrared region and effectively prevented the Cu and (64)Cu atoms in the core from oxidization and dissolution. When conjugated with D-Ala1-peptide T-amide (DAPTA), the core-shell tripods showed great enhancement in targeting the C-C chemokine receptor 5 (CCR5), a newly identified theranostic target up-regulated in triple negative breast cancer (TNBC). Specifically, the CCR5-targeted tripods with an arm length of about 45 nm showed 2- and 6-fold increase in tumor-to-blood and tumor-to-muscle uptake ratios, respectively, relative to their nontargeted counterpart in an orthotopic mouse 4T1 TNBC model at 24 h postinjection. The targeting specificity was further validated via a competitive receptor blocking study. We also demonstrated the use of these targeted, radioactive tripods for effective photothermal treatment in the 4T1 tumor model as guided by PET imaging. The efficacy of treatment was confirmed by the significant reduction in tumor metabolic activity revealed through the use of (18)F-fluorodeoxyglucose PET/CT imaging. Taken together, we believe that the (64)Cu-doped PdCu@Au tripods could serve as a multifunctional platform for both PET imaging and image-guided photothermal cancer therapy.

  19. [Quantitative surface analysis of Pt-Co, Cu-Au and Cu-Ag alloy films by XPS and AES].

    Science.gov (United States)

    Li, Lian-Zhong; Zhuo, Shang-Jun; Shen, Ru-Xiang; Qian, Rong; Gao, Jie

    2013-11-01

    In order to improve the quantitative analysis accuracy of AES, We associated XPS with AES and studied the method to reduce the error of AES quantitative analysis, selected Pt-Co, Cu-Au and Cu-Ag binary alloy thin-films as the samples, used XPS to correct AES quantitative analysis results by changing the auger sensitivity factors to make their quantitative analysis results more similar. Then we verified the accuracy of the quantitative analysis of AES when using the revised sensitivity factors by other samples with different composition ratio, and the results showed that the corrected relative sensitivity factors can reduce the error in quantitative analysis of AES to less than 10%. Peak defining is difficult in the form of the integral spectrum of AES analysis since choosing the starting point and ending point when determining the characteristic auger peak intensity area with great uncertainty, and to make analysis easier, we also processed data in the form of the differential spectrum, made quantitative analysis on the basis of peak to peak height instead of peak area, corrected the relative sensitivity factors, and verified the accuracy of quantitative analysis by the other samples with different composition ratio. The result showed that the analytical error in quantitative analysis of AES reduced to less than 9%. It showed that the accuracy of AES quantitative analysis can be highly improved by the way of associating XPS with AES to correct the auger sensitivity factors since the matrix effects are taken into account. Good consistency was presented, proving the feasibility of this method.

  20. [Cu2R2BrLi(thf)3], R = Si(SiMe3)3–a complex containing five-coordinate silicon in a three-centre two-electron bond (thf = tetrahydrofuran)

    OpenAIRE

    Heine, Andreas; Herbst-Irmer, Regine; Stalke, Dietmar

    1993-01-01

    The title compound is obtained from the reaction of (Me3Si)3SiLi(thf)3 with CuBr in n-hexane and structurally characterised by X-ray diffraction; in [Cu2R2BrLi(thf)3], R = Si(SiMe3)3 one silyl ligand is bridging a very short Cu–Cu bond, resulting in a three-centre two-electron bond, while the second is terminally bound to copper; the other copper atom is linked to a lithium atom via a Cu Br Li bridge. peerReviewed

  1. Inégalité sur le marché du travail au Brésil et en Inde - une étude ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Au Brésil et en Inde, les think tanks unissent leurs forces afin d'examiner les facteurs qui sous-tendent l'inégalité des salaires dans leurs pays et de proposer des options pour réduire l'inégalité sur les marchés du travail. Il est vrai que ces deux économies ont réussi à réduire la pauvreté et à acquérir une certaine influence ...

  2. Weak ferromagnetic behavior, crystal structure, and electronic studies of novel [Cu(II)(Br)(PhCO 2)(Sp)] (Sp=(-)-sparteine) complex

    Science.gov (United States)

    Reyes-Ortega, Yasmi; Alcántara-Flores, José Luis; Hernández-Galindo, María del Carmen; Gutiérrez-Pérez, René; Ramírez-Rosales, Daniel; Bernès, Sylvain; Cabrera-Vivas, Blanca Martha; Durán-Hernández, Alejandro; Zamorano-Ulloa, Rafael

    2006-05-01

    Complex [Cu(II)(Br)(PhCO 2)(Sp)] 1 is obtained starting from copper(0), (-)-sparteine (sp) and benzoyl bromide. 1 Crystallizes in the monoclinic space group P2 1 with a=14.8857(11), b=8.9257(9), c=17.4456(14) Å, β=111.689(5)°, and Z=4. The UV-vis spectrum is characteristic of Cu(II) complexes with tetragonally distorted square pyramidal geometry. The far IR spectrum of 1 shows characteristic vibrations of Cu-Br (239 cm -1), Cu-N (437 cm -1) and Cu-O (466 cm -1) bonds. The 1H NMR broad chemical shifts of 1 integrated for a total of 31 protons and are typical of Cu(II) complexes. ESR spectra of polycrystalline 1 at 77 and 300 K show axial spectra with areas in the ratio A77/ A300=4.02, suggesting a very weak Cu-Cu ferromagnetic interaction. Complex 1-doped with Zn(II) gives hfs with hyperfine interaction constant value A∥=112.45×10 -4 cm -1. The magnetization vs temperature data in the 2-299 K range, show that cupric ion pairs interact through a small antiferromagnetic Heisenberg exchange energy— JS1· S2 with a ground singlet state S=0, separated by J=-1.3 cm -1 from the excited triplet state S=1. The sign of the very weak interchange interaction constant, J, does not agree with the ESR spectra areas ratio of 1 at 77 and 300 K, which is a more accurate quantification of the weak ferromagnetic interaction Cu-Cu through the space.

  3. Ultrathin Epitaxial Cu@Au Core-Shell Nanowires for Stable Transparent Conductors.

    Science.gov (United States)

    Niu, Zhiqiang; Cui, Fan; Yu, Yi; Becknell, Nigel; Sun, Yuchun; Khanarian, Garo; Kim, Dohyung; Dou, Letian; Dehestani, Ahmad; Schierle-Arndt, Kerstin; Yang, Peidong

    2017-05-31

    Copper nanowire networks are considered a promising alternative to indium tin oxide as transparent conductors. The fast degradation of copper in ambient conditions, however, largely overshadows their practical applications. Here, we develop the synthesis of ultrathin Cu@Au core-shell nanowires using trioctylphosphine as a strong binding ligand to prevent galvanic replacement reactions. The epitaxial overgrowth of a gold shell with a few atomic layers on the surface of copper nanowires can greatly enhance their resistance to heat (80 °C), humidity (80%) and air for at least 700 h, while their optical and electrical performance remained similar to the original high-performance copper (e.g., sheet resistance 35 Ω sq-1 at transmittance of ∼89% with a haze factor <3%). The precise engineering of core-shell nanostructures demonstrated in this study offers huge potential to further explore the applications of copper nanowires in flexible and stretchable electronic and optoelectronic devices.

  4. PHENIX results on reconstructed jets in p + p and Cu + Au collisions

    Science.gov (United States)

    Timilsina, Arbin

    2016-12-01

    Measurements of jet production rates in p+p and Cu+Au collisions at √{sNN} = 200 GeV with the PHENIX detector are reported. Jets are reconstructed using the anti-kt algorithm with R = 0.2 from charged particles and electromagnetic clusters. The jet spectra are unfolded to correct for detector effects and underlying event background, and the resulting jet spectra are reported for the transverse momentum range 12

  5. Heavy flavor studies at forward and backward rapidities in Cu+Au collisions with PHENIX detector

    Science.gov (United States)

    da Silva, Cesar; Phenix Collaboration

    2016-09-01

    Asymmetric Cu+Au collisions at √{sNN}=200 GeV performed at RHIC in 2012 open an opportunity to study particle yields in the presence of different mixtures of initial and final state nuclear effects by using probes measured from negative to positive rapidity regions. Heavy flavor yields may be affected by initial state effects on gluons and energy loss in the final state hot medium. The 2012 run was the first where the Forward Vertex Detector (FVTX) was operating. This detector allows the identification of D and B mesons from displaced vertex measurements. Results on B-meson nuclear modification through its J/ ψ decay channel will be presented along with the status of the analysis of semi-leptonic decays of charm and bottom yields.

  6. Stopping Power of Al, Cu, Ag, Au, Pb, and U for 5-18-MeV Protons and Deuterons

    DEFF Research Database (Denmark)

    Sørensen, H.; Andersen, Hans Henrik

    1973-01-01

    High energy protons and deuterons of energies between 9 and 18 MeV have been used to extend earlier measurements of the stopping power of Al, Cu, Ag and Au and the stopping powers of Pb and U in the range 5-18 MeV have been determined for the first time. Mean excitation potentials have been...

  7. Structural characteristics of chalcopyrite from a Cu(Au) ore deposit in the Carajas Mineral Province, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Aparecida Ribeiro, Andreza; Quintao Lima, Diana; Anderson Duarte, Helio; Murad, Enver [ICEx, UFMG, Departamento de Quimica (Brazil); Pereira, Marcio Cesar, E-mail: mcpqui@yahoo.com.br [Universidade Federal dos Vales do Jequitinhonha e Mucuri, Instituto de Ciencia e Tecnologia (Brazil); Tadeu de Freitas Suita, Marcos [UFOP, Departamento de Geologia (Brazil); Ardisson, Jose Domingos [Centro de Desenvolvimento da Tecnologia Nuclear (Brazil); Fabris, Jose Domingos [Universidade Federal dos Vales do Jequitinhonha e Mucuri, UFVJM (Brazil)

    2011-11-15

    Moessbauer spectra and X-ray diffraction data show a chalcopyrite from the Cristalino Cu(Au) deposit in the Carajas Mineral Province in northern Brazil to consist of a single, tetragonal phase. This is in stark contrast to a previously described chalcopyrite from the Camaqua copper mine in southern Brazil, obviously reflecting differences in mineral (and thus ore deposit) genesis.

  8. Stopping Power of Be, Al, Cu, Ag, Pt, and Au for 5-12-MeV Protons and Deuterons

    DEFF Research Database (Denmark)

    Andersen, H.H.; Hanke, C.; Sørensen, H.

    1967-01-01

    Recent measurements on stopping power of aluminum have been continued with the stopping materials Be, Cu, Ag, Pt, and Au. The method of measuring stopping powers utilizing a thermometric compensation technique working at liquid-helium temperature has been used. Results are obtained with a standard...

  9. Ground-state properties of ordered, partially ordered, and random Cu-Au and Ni-Pt alloys

    DEFF Research Database (Denmark)

    Ruban, Andrei; Abrikosov, I. A.; Skriver, Hans Lomholt

    1995-01-01

    We have studied the ground-state properties of ordered, partially ordered, and random Cu-Au and Ni-Pt alloys at the stoichiometric 1/4, 1/2, and 3/4 compositions in the framework of the multisublattice single-site (SS) coherent potential approximation (CPA). Charge-transfer effects in the random...

  10. Crystal and electronic structure study of AgAu and AgCu bimetallic alloy thin films by X-ray techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ozkendir, O. Murat, E-mail: ozkendir@gmail.com [Mersin University, Faculty of Technology, Energy Systems Engineering, Tarsus (Turkey); Mersin University, Institute of Natural Science, Department of Nanotechnology and Advanced Materials, Mersin (Turkey); Cengiz, E. [Karadeniz Technical University, Faculty of Science, Department of Physics, Trabzon (Turkey); Yalaz, E. [Mersin University, Institute of Natural Science, Department of Nanotechnology and Advanced Materials, Mersin (Turkey); Söğüt, Ö.; Ayas, D.H. [Kahramanmaraş Sütçü İmam Üniversitesi, Faculty of Science and Letters, Department of Physics, Kahramanmaraş (Turkey); Thammajak, B. Nirawat [Synchrotron Light Research Institute (Public Organisation), 111 University Avenue, T. Suranaree, A. Muang, Nakhon Ratchasima 30000 (Thailand)

    2016-05-15

    Highlights: • Crystal and electronic properties of bimetallic AgCu and AgAu alloy thin films were studied. • Both AgCu and AgAu bimetallic samples were determined to have cubic crystal geometry. • Strong influence of Cu and Au atoms on the electronic structure of the Ag atoms were determined. - Abstract: Crystal and electronic structure properties of bimetallic AgAu and AgCu alloy thin films were investigated by X-ray spectroscopic techniques. The aim of this study is to probe the influence of Au or Cu atoms on the electronic behaviors of Ag ions in bimetallic alloy materials that yields different crystal properties. To identify the mechanisms causing crystal phase transitions, study were supported by the collected EXAFS (Extended X-ray Absorption Fine Structure) data. Crystal structures of both Cu and Au doped bimetallic Ag samples were determined mainly in cubic geometry with “Fm3m” space group. Through the Ag–Au and Ag–Cu molecular interactions during bimetallic alloy formations, highly overlapped electronic levels that supports large molecular band formations were observed with different ionization states. Besides, traces of the d–d interactions in Au rich samples were determined as the main interplay in the broad molecular bond formations. The exact atomic locations and types in the samples were determined by EXAFS studies and supported by the performed calculations with FEFF scientific code.

  11. Epitaxial growth of unusual 4H hexagonal Ir, Rh, Os, Ru and Cu nanostructures on 4H Au nanoribbons

    KAUST Repository

    Fan, Zhanxi

    2016-09-12

    Metal nanomaterials normally adopt the same crystal structure as their bulk counterparts. Herein, for the first time, the unusual 4H hexagonal Ir, Rh, Os, Ru and Cu nanostructures have been synthesized on 4H Au nanoribbons (NRBs) via solution-phase epitaxial growth under ambient conditions. Interestingly, the 4H Au NRBs undergo partial phase transformation from 4H to face-centered cubic (fcc) structures after the metal coating. As a result, a series of polytypic 4H/fcc bimetallic Au@M (M = Ir, Rh, Os, Ru and Cu) core-shell NRBs has been obtained. We believe that the rational crystal structure-controlled synthesis of metal nanomaterials will bring new opportunities for exploring their phase-dependent physicochemical properties and promising applications.

  12. Cu2ZnSnS4-Au heterostructures: Toward green photocatalytic materials active under visible light

    Science.gov (United States)

    Dilsaver, Patrick Steven

    Solar energy is a potentially limitless source of clean power, but needs an effective means of conversion and storage to be feasible. Semiconductor-metal heterostructures have been studied as potential photocatalysts for use in solar-to-chemical energy conversion as a way of converting solar energy. This thesis examines pathways towards the synthesis of Cu2ZnSnS 4-Au, a novel semiconductor-metal heterostructure. Cu2ZnSnS 4 (CZTS) is attractive for use in this area because it has a narrow bandgap (1.5 eV) and is made of relatively earth-abundant and non-toxic elements. There are four methods studied in this thesis for the fabrication of CZTS-Au, two use AuCl3 as a precursor and two utilize pre-formed Au nanoparticles. Both precursors were studied under thermal and photochemical deposition conditions. The resulting products were characterized to determine the most effective pathway to fabricate these heterostructures. AuCl 3 under thermal deposition conditions proved to be the best pathway due to the well-defined monodisperse product. We also studied whether Au metal islands could be effectively removed while leaving the CZTS nanocrystals intact. The results of this experiment were mixed. It does seem that smaller Au nanoparticles are removed, but larger amalgams remain attached to the CZTS nanorods and remain inseparable despite numerous efforts. Finally, CZTS-Au was tested for photocatalytic activity using the model system of methylene blue reduction. CZTS-Au was found to convert methylene blue to leucomethylene blue at a much higher rate than bare CZTS. These results open up a new area of CZTS-metal heterostructures for the purpose of finding greener photocatalysts for solar-to-chemical energy conversion.

  13. Photoluminescent mixed ligand complexes of CuX (X = Cl, Br, I) with PPh3 and a polydentate imino-pyridyl ligand - Syntheses, structural variations and catalytic property

    Science.gov (United States)

    Ghorai, Anupam; Mondal, Jahangir; Patra, Goutam K.

    2015-10-01

    Three ternary copper(I) complexes [CuI2Cl2(L1)(PPh3)4] (1), [CuI2Br2(L1) (PPh3)4] (2) and [CuI2(μ-I)2 (μ-L1) (PPh3)2]n (3) have been prepared by reactions of CuX (X = Cl, Br and I) with PPh3 and the polydentate imino-pyridyl ligand L1. These complexes have been characterized by elemental analysis, IR, UV-Vis, NMR and X-ray crystallography. From single crystal structural analysis it has been found that complexes 1 and 2 are homo-dinuclear having non-bridging halide ions whereas complex 3 is a 1-D zig-zag co-ordination polymer containing bridged iodide ions. Complexes 1, 2 and 3 are photoluminescent at room temperature in chloroform whereas ligand L1 is non-emissive. The E½ values of the CuIsbnd CuII couple of 1, 2 and 3 are 0.98 V, 0.92 V and 0.42 V respectively (vs Ag/AgCl in 1 M KCl, scan rate 100 mV s-1). All three complexes function as effective catalysts for the synthesis of 2-substituted benzoxazoles.

  14. The Effect of the Redox Potential of Aqua Regia and Temperature on the Au, Cu, and Fe Dissolution from WPCBs

    Directory of Open Access Journals (Sweden)

    Heini Elomaa

    2017-09-01

    Full Text Available Constant growth in waste electrical and electronic equipment (WEEE levels necessitates the development of new, commercially viable recycling processes. Waste printed circuit boards (WPCBs are a sub-group of WEEE that are of increasing interest due to their relatively high level of valuable metal content including Au, Ag, and platinum group metals (PGMs. Currently, precious metals like gold are mainly recycled from WEEE streams through copper smelting/refining; however, the possibility to peel gold from WPCBs prior to smelting, could offer advantages for recycling. In this study, the suitability of aqua regia for selective or partially selective gold leaching from un-crushed WPCBs was investigated. The redox potential of aqua regia solutions and the dissolution efficiencies of Au, Cu, and Fe from WPCBs were investigated at different temperatures (40–80 °C and concentrations (2–32% in batch leaching tests. The redox potential of aqua regia solution was found to depend on concentration and temperature. It is suggested that Au dissolution in aqua regia requires dissolved Cu2+ ions originating from the WPCB material to work. Au extraction (>50% was shown to require a redox potential >700 mV with [Cu2+] > 2500 ppm, as a potential >850 mV alone was insufficient without cupric ions. Significant amounts of Au and Cu could be dissolved with only minor Fe dissolution at ≥8% aqua regia at 80 °C. Results suggest that leaching of uncrushed WPCBs in 8% aqua regia (T = 80 °C can provide the opportunity for partial Au recovery prior to further processing.

  15. Brazing of zirconia to titanium using Ag-Cu and Au-Ni filler alloys

    Directory of Open Access Journals (Sweden)

    Jean S. Pimenta

    2013-12-01

    Full Text Available Advanced ceramic is usually joined to metal by the well-known direct brazing process, where costly active filler alloys can be considered a limitation. Brazing using active-metal-free filler alloy as insert between the joint components is an attempt to overcome it. The active metal diffusion from the titanium member through the bulk of molten filler to the ceramic was responsible to produce an active filler alloy in loco and promote reduction of the zirconium oxide to improve wetting on the ceramic surface. Unalloyed titanium was joined in a high-vacuum furnace (<3x10-5 mbar to yttria-tetragonal zirconia polycristals (Y-TZP and zirconia partially stabilized with magnesia (Mg-PSZ, where commercial fillers Ag-28Cu and Au-18Ni with respective thermal cycles were evaluated. Helium gas leak detection test was performed at the ceramic/metal interface at room temperature; samples from reliable vacuum tight joints were examined by microstructural analysis techniques and energy dispersive X-ray analysis at the joint cross-section. Tight joints were produced with eutectic Ag-Cu filler, revealing an intermetallic layer and a dark reaction layer near the ceramic surface; titanium diffusion was efficient for superficial chemical interactions between individual components. Brazing joints were also tested using three-point flexure testing.

  16. Organic Superconductor k-(BEDT-TTF)2Cu[N(CN)2]Br - A Tunable Electronic System across the Mott Transition -

    Science.gov (United States)

    Tokumoto, M.; Kinoshita, N.; Tanaka, Y.; Kinoshita, T.; Anzai, H.

    1998-03-01

    k-(BEDT-TTF)2Cu[N(CN)2]Br, is an organic superconductor with the highest Tc of 11.6K at ambient pressure (A. M. Kini et al., Inorg. Chem. 29, 2555 (1990)). We have reported a normal isotope effect,when all the hydrogen atoms of BEDT-TTF are replaced with deuterium, in other words, Tc was depressed by as much as 0.9 K (M. Tokumoto et al., J. Phys. Soc. Jpn. 60, 1426 (1991)), in contrast to the "inverse isotope effect" commonly observed in organic superconductors (K. Oshima, et al., Synth. Metals 27, A473 (1988)) . Recently, it was reported that the deuterated k-(BEDT-TTF)2Cu[N(CN)2]Br is of an insulating nature similar to k-(BEDT-TTF)2Cu[N(CN)2]Cl when cooled rapidly(Y. Nakazawa and K. Kanoda, Phys. Rev. B 53, R8875 (1996)). Here we report on the results of reexamination of the superconducting transition of deuterated k-(BEDT-TTF)2Cu[N(CN)2]Br by SQUID measurements with special attention to the cooling speed ranging from 10K/min to less than 0.01K/min. We observed a significant effect not only on the superconducting transition temperature Tc but also on the superconducting volume fraction.

  17. Pt skin on AuCu intermetallic substrate: a strategy to maximize Pt utilization for fuel cells.

    Science.gov (United States)

    Wang, Gongwei; Huang, Bing; Xiao, Li; Ren, Zhandong; Chen, Hao; Wang, Deli; Abruña, Héctor D; Lu, Juntao; Zhuang, Lin

    2014-07-09

    The dependence on Pt catalysts has been a major issue of proton-exchange membrane (PEM) fuel cells. Strategies to maximize the Pt utilization in catalysts include two main approaches: to put Pt atoms only at the catalyst surface and to further enhance the surface-specific catalytic activity (SA) of Pt. Thus far there has been no practical design that combines these two features into one single catalyst. Here we report a combined computational and experimental study on the design and implementation of Pt-skin catalysts with significantly improved SA toward the oxygen reduction reaction (ORR). Through screening, using density functional theory (DFT) calculations, a Pt-skin structure on AuCu(111) substrate, consisting of 1.5 monolayers of Pt, is found to have an appropriately weakened oxygen affinity, in comparison to that on Pt(111), which would be ideal for ORR catalysis. Such a structure is then realized by substituting the Cu atoms in three surface layers of AuCu intermetallic nanoparticles (AuCu iNPs) with Pt. The resulting Pt-skinned catalyst (denoted as Pt(S)AuCu iNPs) has been characterized in depth using synchrotron XRD, XPS, HRTEM, and HAADF-STEM/EDX, such that the Pt-skin structure is unambiguously identified. The thickness of the Pt skin was determined to be less than two atomic layers. Finally the catalytic activity of Pt(S)AuCu iNPs toward the ORR was measured via rotating disk electrode (RDE) voltammetry through which it was established that the SA was more than 2 times that of a commercial Pt/C catalyst. Taking into account the ultralow Pt loading in Pt(S)AuCu iNPs, the mass-specific catalytic activity (MA) was determined to be 0.56 A/mg(Pt)@0.9 V, a value that is well beyond the DOE 2017 target for ORR catalysts (0.44 A/mg(Pt)@0.9 V). These findings provide a strategic design and a realizable approach to high-performance and Pt-efficient catalysts for fuel cells.

  18. Luminescent Di and Polynuclear Organometallic Gold(I)-M (Au2, {Au2Ag}n and {Au2Cu}n) Compounds Containing Bidentate Phosphanes as Active Antimicrobial Agents

    Science.gov (United States)

    Frik, Malgorzata; Jiménez, Josefina; Gracia, Ismael; Falvello, Larry R.; Abi-Habib, Sarya; Suriel, Karina; Muth, Theodore R.

    2012-01-01

    The reaction of new dinuclear gold(I) organometallic complexes containing mesityl ligands and bridging bidentate phosphanes [Au2(mes)2(μ-LL)] (LL = dppe: 1,2-Bis(di-phenylphosphano)ethane 1a, and water-soluble dppy: 1,2-Bis(di-3-pyridylphosphano)ethane 1b) with Ag+ and Cu+ lead to the formation of a family of heterometallic clusters with mesityl bridging ligands of the general formula [Au2M(μ-mes)2(μ-LL)]A (M = Ag, A = ClO4−, L-L = dppe 2a, dppy 2b; M = Ag, A = SO3CF3−, L-L = dppe 3a, dppy 3b; M = Cu, A = PF6−, L-L = dppe 4a, dppy 4b). The new compounds were characterized by different spectroscopic techniques and mass spectrometry The crystal structures of [Au2(mes)2(μ-dppy)] 1b and [Au2Ag(μ-mes)2(μ-dppe)]SO3CF3 3a were determined by a single-crystal X-ray diffraction study. 3a in solid state is not a cyclic trinuclear Au2Ag derivative but it gives an open polymeric structure instead, with the {Au2(μ-dppe)} fragments “linked” by Ag(μ-mes)2 units. The very short distances of 2.7559(6) Å (Au-Ag) and 2.9229(8) Å (Au-Au) are indicative of gold-silver (metallophillic) and aurophilic interactions. A systematic study of their luminescence properties revealed that all compounds are brightly luminescent in solid state, at room temperature (RT) and at 77 K, or in frozen DMSO solutions with lifetimes in the microsecond range and probably due to the self-aggregation of [Au2M(μ-mes)2(μ-LL)]+ units (M= Ag or Cu; LL= dppe or dppy) into an extended chain structure, through Au-Au and/or Au-M metallophylic interactions, as that observed for 3a. In solid state the heterometallic Au2M complexes with dppe (2a–4a) show a shift of emission maxima (from ca. 430 to the range of 520–540 nm) as compared to the parent dinuclear organometallic product 1a while the complexes with dppy (2b–4b) display a more moderate shift (505 for 1b to a max of 563 nm for 4b). More importantly, compound [Au2Ag(μ-mes)2(μ-dppy)]ClO4 2b resulted luminescent in diluted DMSO solution

  19. Luminescent di- and polynuclear organometallic gold(I)-metal (Au2, {Au2Ag}n and {Au2Cu}n) compounds containing bidentate phosphanes as active antimicrobial agents.

    Science.gov (United States)

    Frik, Malgorzata; Jiménez, Josefina; Gracia, Ismael; Falvello, Larry R; Abi-Habib, Sarya; Suriel, Karina; Muth, Theodore R; Contel, María

    2012-03-19

    The reaction of new dinuclear gold(I) organometallic complexes containing mesityl ligands and bridging bidentate phosphanes [Au(2)(mes)(2)(μ-LL)] (LL=dppe: 1,2-bis(diphenylphosphano)ethane 1a, and water-soluble dppy: 1,2-bis(di-3-pyridylphosphano)ethane 1b) with Ag(+) and Cu(+) lead to the formation of a family of heterometallic clusters with mesityl bridging ligands of the general formula [Au(2)M(μ-mes)(2) (μ-LL)][A] (M=Ag, A=ClO(4)(-), LL=dppe 2a, dppy 2b; M=Ag, A=SO(3)CF(3)(-), LL=dppe 3a, dppy 3b; M=Cu, A=PF(6)(-), LL=dppe 4a, dppy 4b). The new compounds were characterized by different spectroscopic techniques and mass spectrometry The crystal structures of [Au(2)(mes)(2)(μ-dppy)] (1b) and [Au(2)Ag(μ-mes)(2)(μ-dppe)][SO(3)CF(3)] (3a) were determined by a single-crystal X-ray diffraction study. 3a in solid state is not a cyclic trinuclear Au(2)Ag derivative but it gives an open polymeric structure instead, with the {Au(2)(μ-dppe)} fragments "linked" by {Ag(μ-mes)(2)} units. The very short distances of 2.7559(6) Å (Au-Ag) and 2.9229(8) Å (Au-Au) are indicative of gold-silver (metallophilic) and aurophilic interactions. A systematic study of their luminescence properties revealed that all compounds are brightly luminescent in solid state, at room temperature (RT) and at 77 K, or in frozen DMSO solutions with lifetimes in the microsecond range and probably due to the self-aggregation of [Au(2)M(μ-mes)(2)(μ-LL)](+) units (M=Ag or Cu; LL=dppe or dppy) into an extended chain structure, through Au-Au and/or Au-M metallophilic interactions, as that observed for 3a. In solid state the heterometallic Au(2)M complexes with dppe (2a-4a) show a shift of emission maxima (from ca. 430 to the range of 520-540 nm) as compared to the parent dinuclear organometallic product 1a while the complexes with dppy (2b-4b) display a more moderate shift (505 for 1b to a max of 563 nm for 4b). More importantly, compound [Au(2)Ag(μ-mes)(2)(μ-dppy)]ClO(4) (2b) resulted

  20. Fabrication of a Cu{sub 2}O/Au/TiO{sub 2} composite film for efficient photocatalytic hydrogen production from aqueous solution of methanol and glucose

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xi; Dong, Haitai; Hu, Zhe; Qi, Zhong; Li, Laisheng, E-mail: llsh@scnu.edu.cn

    2017-05-15

    Highlights: • A Cu{sub 2}O/Au/TiO{sub 2} film was synthesized successfully. • Hydrogen production of Cu{sub 2}O/Au/TiO{sub 2} film improved significantly. • The highest hydrogen production rate of the film was 125.3 mmol/h/m{sup 2}. • A Z-scheme charge transfer pathway was proposed. - Abstract: A novel Cu{sub 2}O/Au/TiO{sub 2} photocatalyst composite film was fabricated on a copper substrate for photocatalytic hydrogen production. The composite films, Cu{sub 2}O/Au/TiO{sub 2}, were stepwise synthesized by using electrochemical deposition, photodeposition, and coating methods. First, a Cu{sub 2}O film was synthesized using the electrochemical deposition method, after which Au was deposited onto the Cu{sub 2}O film through in-site photodeposition. Finally, TiO{sub 2} was coated on the surface of the Cu{sub 2}O/Au film. Its morphology and surface chemical composition was characterized by SEM, TEM, XRD and XPS. The optical characteristics (UV–Vis DRS, PL spectrum) of the films were also examined. The photocatalytic hydrogen production rate of the Cu{sub 2}O/Au/TiO{sub 2} composite film from a 20% vol. methanol solution increased to125.3 mmol/h/m{sup 2} under 300 W xenon lamp light irradiation. Compared to the TiO{sub 2} (13.5 mmol/h/m{sup 2}) film and Cu{sub 2}O/TiO{sub 2} film (83.2 mmol/h/m{sup 2}), the Cu{sub 2}O/Au/TiO{sub 2} film showed excellent photocatalytic performance for hydrogen generation. The Cu{sub 2}O/Au/TiO{sub 2} film has highly effective photocatalytic properties, which are attributed to the Z-scheme system and can not only enhance the absorption of solar light but also suppress the recombination of photogenerated electron-hole pairs. It is worth noting that by introducing Au into the interface of Cu{sub 2}O/TiO{sub 2}, the surface plasmon resonance (SPR)-induced local electric field formed at the Au site induces a Z-scheme charge transfer pathway inside the composite film (Cu{sub 2}O/Au/TiO{sub 2}), which promotes both the charge of the

  1. Santé mentale et citoyenneté : éliminons les obstacles au Brésil et ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    14 avr. 2015 ... Leishmaniose : maladie sans frontières. Une mouche porteuse d'un parasite mortel hante la jungle des chutes d'Iguazu, qui marque la triple frontière entre le Brésil, l'Argentine et le. Voir davantageLeishmaniose : maladie sans frontières ...

  2. Stable structures and potential energy surface of the metallic clusters: Ni, Cu, Ag, Au, Pd, and Pt

    Science.gov (United States)

    Wu, Xia; Sun, Yan

    2017-06-01

    Metallic clusters have been widely studied due to their special electrical, optical, and catalytic properties. The many-body Gupta potential is applied to describe the interatomic interaction of Ni, Cu, Ag, Au, Pd, and Pt clusters, and their global minimal structures within 100 atoms are optimized using dynamic lattice searching (DLS) method. The configurational distribution of global minima is analyzed, and the geometrical difference among these clusters is demonstrated. Results show that the dominant motif of Ni and Cu clusters is the icosahedron, and in Ag and Au clusters the number of decahedra is slightly larger than that of the icosahedra. However, more face-centered cubic (fcc), stacking fault fcc, and amorphous structures are formed in Au clusters than in Ag clusters. Furthermore, the main motif of Pd and Pt clusters is the decahedron. In particular, Ni98 adopts a Leary tetrahedral motif, and Pt54 is a central vacant icosahedron. The difference related to the potential parameters of these metallic clusters is further investigated by energy analysis. Moreover, the potential energy surfaces (PES) of 38-atom metallic clusters is characterized in terms of conformational analysis. It was found that the sequence of the number of local minima on the PES from large to low is Ni, Cu, Ag, Pt, Pd, and Au.

  3. 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.

  4. Hysteresis effect of ammonium and water protons by 1H MAS NMR in (NH4)2CuBr4·2H2O

    Science.gov (United States)

    Lim, Ae Ran; Cho, Jiung

    2017-10-01

    The chemical shifts, linewidths, and spin-lattice relaxation times for ammonium and water protons in (NH4)2CuBr4·2H2O were investigated by 1H magic angle spinning nuclear magnetic resonance (MAS NMR) with a focus on the roles of NH4+ and H2O at high temperatures. The changes in the temperature dependence of the data near Td (=360 K) were related to variations of the H environments; the mechanism above Td was related to hydrogen-bond transfer involving breakage of the weak part of the hydrogen bond. The hysteresis effects for the ammonium and water protons in (NH4)2CuBr4·2H2O by MAS NMR were described with respect to heating and cooling.

  5. Spontaneous piezoelectric effect as order parameter in (NH{sub 4}){sub 2}CuBr{sub 4}·2H{sub 2}O crystal

    Energy Technology Data Exchange (ETDEWEB)

    Tylczyński, Z., E-mail: zbigtyl@amu.edu.pl; Wiesner, M.; Trzaskowska, A.

    2016-11-01

    Temperature change of piezoelectric properties of (NH{sub 4}){sub 2}CuBr{sub 4}·2H{sub 2}O crystal in the low-temperature ferroelastoelectric phase is studied. The macroscopic order parameter is proved to be the h{sub 36} component of the spontaneous piezoelectric tensor. The critical exponent related with the phase transition is α=0.60±0.05.

  6. Measurement of electrons from heavy-flavor decays from $p$+$p$, $d$+Au, and Cu+Cu collisions in the PHENIX experiment

    CERN Document Server

    Lim, Sanghoon

    2014-01-01

    Charm and bottom quarks are formed predominantly by gluon fusion in the initial hard scatterings at RHIC, making them good probes of the full medium evolution. Previous measurements at RHIC have shown large suppression and azimuthal anisotropy of open heavy-flavor hadrons in Au+Au collisions at $\\sqrt{s_{NN}}=200~{\\rm GeV}$. Explaining the simultaneously large suppression and flow of heavy quarks has been challenging. To further understand the heavy-flavor transport in the hot and dense medium, it is imperative to also measure cold nuclear matter effects which affect the initial distribution of heavy quarks as well as the system size dependence of the final state suppression. In this talk, new measurements by the PHENIX collaboration of electrons from heavy-flavor decays in $p$+$p$, $d$+Au, and Cu+Cu collisions at $\\sqrt{s_{NN}}=200~{\\rm GeV}$ are presented. In particular, a surprising enhancement of intermediate transverse momentum heavy-flavor decay leptons in $d$+Au at mid and backward rapidity are also se...

  7. CO adsorption on graphite-like ZnO bilayers supported on Cu(111), Ag(111) and Au(111) surfaces

    OpenAIRE

    Tosoni, Sergio; Li, Cequn; Schlexer, Philomena; Pacchioni, Gianfranco

    2017-01-01

    Graphitic-like ZnO bilayer films deposited on coinage metals, Cu(111), Ag(111), and Au(111) have been studied by density functional theory calculations including dispersion corrections. The scope is to compare on an equal footing the properties of the three systems and in particular the nature of the metal/oxide interface. To this end we have considered the adsorption of a CO probe molecule and the vibrational shifts induced by adsorption on ZnO/Cu(111), ZnO/Ag(111)...

  8. La genèse du concept d’« homme baroque » en Amérique latine et au Brésil

    Directory of Open Access Journals (Sweden)

    Guiomar de Grammont

    2012-06-01

    Full Text Available Cette étude traite des conditionnements matériels, institutionnels et rhétoriques de la production artistique du xviiie siècle, afin de rendre évident que le terme « baroque » et les catégories psychologiques et expressives qui lui sont associées dans plusieurs de ces discours sont étrangers aux pratiques effectives des artisans luso-brésiliens de l’époque. Cet article est une lecture critique des discours en tous genres qui depuis le xixe siècle ont créé le « héros culturel », précurseur de la « soi-disant » « identité culturelle brésilienne », dans le projet de construction de l’idée de Nation mené par l’Institut Historique et Géographique Brésilien à partir de 1838. Le mythe ainsi construit a été repris postérieurement comme une évidence historique en divers programmes de l’histoire des idées sur les arts et les lettres au Brésil, au cours des xixe et xxe siècle.This study deals with the material, institutional and rhetorical conditioning of the artistic production of the 18th century, to highlight that the term ‘baroque’ and the psychologist and expressive categories associated to it in many of the discourses are exterior to the effective practices of Luso-Brazilian artists of that time.  This paper is a critical reading of the discourses in many genres which, since the 19th century, have produced the ‘cultural hero’ precursor of the supposed “Brazilian cultural identity” in the project to build the idea of Nation carried out by the Brazilian Geography and History Institute since 1838. The myth therefore built in fiction was reappropriated as historical evidence, later, in many programs of history of the thought about arts and literature in Brazil, in the 19th and 20th centuries.

  9. Participant and spectator scaling of spectator fragments in Au+Au and Cu+Cu collisions at sqrt(sNN) = 19.6 and 22.4 GeV

    CERN Document Server

    Alver, B; Baker, M D; Ballintijn, M; Barton, D S; Betts, R R; Bickley, A A; Bindel, R; Budzanowski, A; Busza, W; Carroll, A; Chai, Z; Chetluru, V; Decowski, M P; Garcia, E; Gburek, T; George, N; Gulbrandsen, K; Gushue, S; Halliwell, C; Hamblen, J; Harnarine, I; Heintzelman, G A; Henderson, C; Hofman, D J; Hollis, R S; Holynski, R; Holzman, B; Iordanova, A; Johnson, E; Kane, J L; Katzy, J; Khan, N; Kucewicz, W; Kulinich, P; Kuo, C M; Li, W; Lin, W T; Loizides, C; Manly, S; McLeod, D; Mignerey, A C; Nouicer, R; Olszewski, A; Pak, R; Park, I C; Pernegger, H; Reed, C; Remsberg, L P; Reuter, M; Richardson, E; Roland, C; Roland, G; Rosenberg, L; Sagerer, J; Sarin, P; Sawicki, P; Sedykh, I; Skulski, W; Smith, C E; Stankiewicz, M A; Steinberg, P; Stephans, G S F; Sukhanov, A; Szostak, A; Tang, J L; Tonjes, M B; Trzupek, A; Vale, C; van Nieuwenhuizen, G J; Vaurynovich, S S; Verdier, R; Veres, G I; Walters, P; Wenger, E; Willhelm, D; Wolfs, F L H; Wosiek, B; Wozniak, K; Wuosmaa, A H; Wyngaardt, S; Wyslouch, B

    2015-01-01

    Spectator fragments resulting from relativistic heavy ion collisions, consisting of single protons and neutrons along with groups of stable nuclear fragments up to Nitrogen (Z=7), are measured in PHOBOS. These fragments are observed in Au+Au (sqrt(sNN)=19.6 GeV) and Cu+Cu (22.4 GeV) collisions at high pseudorapidity ($\\eta$). The dominant multiply-charged fragment is the tightly bound Helium ($\\alpha$), with Lithium, Beryllium, and Boron all clearly seen as a function of collision centrality and pseudorapidity. We observe that in Cu+Cu collisions, it becomes much more favorable for the $\\alpha$ fragments to be released than Lithium. The yields of fragments approximately scale with the number of spectator nucleons, independent of the colliding ion. The shapes of the pseudorapidity distributions of fragments indicate that the average deflection of the fragments away from the beam direction increases for more central collisions. A detailed comparison of the shapes for $\\alpha$ and Lithium fragments indicates tha...

  10. Measurements of the work function of single-walled carbon nanotubes encapsulated by AgI, AgCl, and CuBr using Kelvin probe technique with different kinds of probes

    Energy Technology Data Exchange (ETDEWEB)

    Zhukov, A. A., E-mail: azhukov@issp.ac.ru [Russian Academy of Science, Institute of Solid State Physics (Russian Federation); Chernysheva, M. V.; Eliseev, A. A. [Moscow State University, Department of Materials Science (Russian Federation)

    2016-07-15

    We report the results on the measurements of the work function of single-walled carbon nanotubes encapsulated by Agl (AgI@SWCNT), AgCl (AgCl@SWCNT), and CuBr (CuBr@SWCNT) by the local Kelvin probe technique. We found the values of the work function of tubes encapsulated with AgI and AgCl (Φ(AgI@SWCNT) = 5.08 ± 0.02, Φ(AgCl@SWCNT) = 5.10 ± 0.02 eV) to exceed substantially that of pristine carbon nanotubes, and the value of the work function of carbon nanotubes encapsulated with CuBr is Φ(CuBr@SWCNT) = 4.89 ± 0.03 (eV). The measurements are carried out using different kinds of microscope probes including multi-walled carbon nanotube tips.

  11. Des comptoirs littoraux au continent, la poussée pionnière brésilienne

    Directory of Open Access Journals (Sweden)

    Hervé THÉRY

    1993-03-01

    Full Text Available Deux séries de cartes extraites de l’Atlas nacional do Brasil, publié par l’IBGE en 1992, montrent l’ampleur et la rapidité de la conquête pionnière qui a transformé l’intérieur du pays, alors que pendant des siècles le Brésil «utile» s’était réduit à un mince liséré côtier.

  12. Reversible and irreversible changes of surface morphology by order-disorder transition in CuAu alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sachl, Jindrich; Sima, Vladimir; Pfeiler, Wolfgang

    2004-09-22

    The change of symmetry from the disordered fcc structure to tetragonal or orthorhombic structure is accompanied in CuAu alloy by anisotropy of lattice parameters and also by local generation of c-variants of structural antiphase domains. Macroscopic results of these processes can be observed as a dynamic change of the surface morphology. Some surface changes are reversible, on the other hand the internal stresses connected with the order-disorder transformation are also responsible for irreversible surface deformation effects. The domain structure formation can be influenced by external load and a shape memory effect can be observed at special conditions in CuAu. A combination of in-situ microscopic video cinematography and post-mortem 3-D atomic force microscopy (AFM) has been used for the surface study. The AFM images have enabled a detailed analysis of the surface morphology and the cinematography has given an in-situ information dealing with conditions and kinetics of observed surface changes. Measurements on CuAu single- and poly-crystalline samples have been made for a wide variety of experimental conditions (heating/cooling rates, external load, thermal history of the sample)

  13. Neyshabour turquoise mine: the first Iron Oxide Cu-Au-U-LREE (IOCG mineralized system in Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Hasan Karimpour

    2011-11-01

    Full Text Available Neyshabour turquoise mine is located in northwest of Neyshabour, southern Quchan volcanic belt. Eocene andesite and dacite forming as lava and pyroclastic rocks cover most of the area. Subvolcanic diorite to syenite porphyry (granitoids of magnetite series intruded the volcanic rocks. Both volcanic and subvolcanic rocks are highly altered. Four types of alteration are recognized including: silicification, argillic, calcification and propylitic. Silicification is dominant followed by argillic alteration. Mineralization is present as stockwork, disseminated and hydrothermal breccia. Hypogene minerals are pyrite, magnetite, specularite, chalcopyrite, and bornite. Secondary minerals are turquoise, chalcocite, covellite, and iron oxides. A broad zone of gossan has developed in the area. Oxidized zone has a thickness of about 80 m. Mineralized samples show high anomalies of Cu, Au, Zn, As, Mo, Co, U, LREE, Nb, and Th. Both aeromagnetic and radiometric (U and Th maps show very strong anomalies (10 × 5km within the mineralized area. Based on geology, alteration, mineralization, geochemistry, and geophysics, Neyshabour turquoise mine is a large Iron oxide Cu-Au-U-LREE (IOCG mineralized system. In comparison with other IOCG deposits, it has some similarities with Olympic Dam (Australia and Candelaria (Chile. In comparison with Qaleh Zari and Kuh Zar mines, Neyshabour turquoise mine is the first Iron oxide Cu-Au-U-LREE (IOCG mineralized system discovered in Iran.

  14. The interaction between atoms of Au and Cu with clean Si(111) surface: a study combining synchrotron radiation grazing incidence X-ray fluorescence analysis and theoretical calculations.

    Science.gov (United States)

    de Carvalho, Hudson W P; Batista, Ana P L; Ramalho, Teodorico C; Pérez, Carlos A; Gobbi, Angelo Luiz

    2009-09-15

    In order to evaluate the interactions between Au/Cu atoms and clean Si(111) surface, we used synchrotron radiation grazing incidence X-ray fluorescence analysis and theoretical calculations. Optimized geometries and energies on different adsorption sites indicate that the binding energies at different adsorption sites are high, suggesting a strong interaction between metal atom and silicon surface. The Au atom showed higher interaction than Cu atom. The theoretical and experimental data showed good agreement.

  15. Diffusion of single Au, Ag and Cu atoms inside Si(111)-(7 × 7) half unit cells: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qin [Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055 (China); Department of Physics, The Chinese University of Hong Kong, Shatin, New Territory, Hong Kong (China); Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang, Sichuan 621908 (China); Fu, Qiang [Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, Zum Großen Windkanal 6, 12489 Berlin (Germany); Shao, Xiji; Ma, Xuhang; Wu, Xuefeng [Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055 (China); Wang, Kedong, E-mail: wangkd@sustc.edu.cn [Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055 (China); Xiao, Xudong, E-mail: xdxiao@phy.cuhk.edu.hk [Department of Physics, The Chinese University of Hong Kong, Shatin, New Territory, Hong Kong (China)

    2017-04-15

    Highlights: • Diffusions of Au, Ag and Cu atoms in the half unit cells of Si(111)-(7×7) have been studied by using a STM-based I-t method. • Despite their similar absorption sites, the diffusion dynamics show obvious differences between Ag and the other two. • Theoretical calculations suggest that different potential energy profiles are responsible for the observed differences. - Abstract: The diffusion behaviors of single Au, Ag and Cu atoms on Si(111)-(7 × 7) half unit cells have been investigated via combining scanning tunneling microscopy and first-principles calculations. Despite the similar adsorption sites between both half unit cells among these elements, the diffusion dynamics show obvious differences between Ag and the other two. Although obvious asymmetry has been found in the diffusion behaviors of Au and Cu atoms in two half unit cells of Si(111)-(7 × 7), the asymmetry behaves in a way different from that of Ag atoms and no dual-time character has been observed for the diffusions of Au and Cu in both half unit cells. Theoretical calculations suggest a different potential energy profile caused by the stronger hybridization between d states of Au (Cu) and Si states make the concept of basin useless for the diffusion of Au and Cu atoms inside the half unit cells of Si(111)-(7 × 7).

  16. The late Oligocene Cevizlidere Cu-Au-Mo deposit, Tunceli Province, eastern Turkey

    Science.gov (United States)

    İmer, Ali; Richards, Jeremy P.; Creaser, Robert A.; Spell, Terry L.

    2015-02-01

    The Cevizlidere deposit, located in the Tunceli Province of eastern Anatolia, is the largest porphyry Cu-Au-Mo system in Turkey. The deposit is spatially related to a composite stock, which was emplaced into Paleozoic limestones and Paleogene andesitic rocks to the southeast of the Munzur mountains, near the southwestern margin of the Ovacık pull-apart basin. The host plutonic rocks at Cevizlidere are porphyritic, medium-K calc-alkaline diorites and granodiorites. 40Ar/39Ar incremental step-heating analysis of two igneous biotite separates obtained from syn-mineral diorite porphyry yielded late Oligocene cooling ages of 25.49 ± 0.10 and 25.10 ± 0.14 Ma, whereas hydrothermal biotite yielded an age of 24.73 ± 0.08 Ma. Re-Os ages obtained from two molybdenite separates (24.90 ± 0.10 and 24.78 ± 0.10 Ma) indicate that porphyry-style alteration and mineralization developed shortly after magma emplacement. The whole-rock geochemical composition of the Cevizlidere porphyry intrusions is consistent with derivation from partial melting of the metasomatized supra-subduction zone mantle. However, based on regional tectonic reconstructions, Oligocene magmatic activity in this area appears to be related to a major kinematic reorganization that took place at around 25 Ma, during the switch from subduction to collisional tectonics in eastern Anatolia. This kinematic switch may be attributed to break-off of the Southern Neo-Tethys oceanic slab prior to the Arabia-Eurasia continent-continent collision (~12-10 Ma) following widespread middle Eocene (50-43 Ma) arc/back-arc magmatism. In this respect, the subduction-related tectonic setting of the late Oligocene Cevizlidere porphyry deposit is similar to that of the middle Eocene Çöpler epithermal Au deposit. The late timing of Cevizlidere with respect to the Southern Neo-Tethys subduction may be comparable to some early to late Miocene porphyry-epithermal systems that lie within the contiguous Urumieh-Dokhtar belt in central

  17. Age-hardenability and related microstructural changes during and after phase transformation in an Au-Ag-Cu-based dental alloy

    Directory of Open Access Journals (Sweden)

    Hyung-Il Kim

    2012-01-01

    Full Text Available The aim of this study was to clarify how the microstructural changes during and after phase transformation determine the age-hardenability of an Au-Ag-Cu-based dental alloy. The rapid increase in hardness in the initial stage was the result of rapid atomic diffusion by spinodal decomposition into metastable Ag-rich' and Cu-rich' phases. The constant hardening after apparent initial hardening was the result of a subsequent transformation of the metastable Ag-rich' and Cu-rich' phases to the stable Ag-rich α1phase and AuCu I phase through the metastable AuCu I' phase. During the increase in hardness, fine block-like structure with high coherency formed in the grain interior, which changed to a fine cross-hatched structure. A relatively coarse lamellar structure composed of Ag-rich α1and AuCu I phases grew from the grain boundaries, initiating softening before the grain interior reached its maximum hardness. As a result, the spinodal decomposition attributed to rapid hardening by forming the fine block-like structure, and the subsequent ordering into AuCu I, which is a famous hardening mechanism, weakened its hardening effect by accelerating the lamellar-forming grain boundary reaction.

  18. Age-hardenability and related microstructural changes during and after phase transformation in an Au-Ag-Cu-based dental alloy

    Directory of Open Access Journals (Sweden)

    Hyung-Il Kim

    2013-02-01

    Full Text Available The aim of this study was to clarify how the microstructural changes during and after phase transformation determine the age-hardenability of an Au-Ag-Cu-based dental alloy. The rapid increase in hardness in the initial stage was the result of rapid atomic diffusion by spinodal decomposition into metastable Ag-rich' and Cu-rich' phases. The constant hardening after apparent initial hardening was the result of a subsequent transformation of the metastable Ag-rich' and Cu-rich' phases to the stable Ag-rich α1phase and AuCu I phase through the metastable AuCu I' phase. During the increase in hardness, fine block-like structure with high coherency formed in the grain interior, which changed to a fine cross-hatched structure. A relatively coarse lamellar structure composed of Ag-rich α1and AuCu I phases grew from the grain boundaries, initiating softening before the grain interior reached its maximum hardness. As a result, the spinodal decomposition attributed to rapid hardening by forming the fine block-like structure, and the subsequent ordering into AuCu I, which is a famous hardening mechanism, weakened its hardening effect by accelerating the lamellar-forming grain boundary reaction.

  19. Sulfide mineral paragenesis at the Hugo Dummett porphyry Cu-Au deposit, Oyu Tolgoi, South Mongolia

    Science.gov (United States)

    Sanjaa, M.; Fujimaki, H.

    2008-12-01

    Mineralogical studies of ore minerals have been conducted for the Hugo Dummett porphyry copper deposit. The Hugo Dummett porphyry copper gold deposit is located in the South Gobi region, Mongolia and currently being explored. This deposit divided into the Cu-rich South Hugo Dummett and the Cu-Au-rich North Hugo Dummett deposits. The Hugo Dummett deposits contain 1.08% copper (1.16 billion tonnes in total) and 0.23 g/t gold. Copper-gold mineralizations at this deposit are centered on a high-grade copper (typically > 2.5%) and gold (0.5-2 g/t) zone of intense quartz stockwork veining. The high grade copper and gold zone is mainly within the Late Devonian quartz monzodiorite intrusions and augite basalt, also locally occurs in dacitic rocks. Intense quartz veining forms a lens up to 100 m wide hosted by augite basalt and partly by quartz monzodiorite. Although many explorations have been carried out, but only a few scientific works were done in the Oyu Tolgoi mining area. Therefore the nature of copper-gold mineralization and orgin of the deposit is not fully understood. North Hugo Dummett and South Hugo Dummett porphyry copper-gold deposits are characterized by three mineralized stages based on our study: (1) early stage (2) middle stage and (3) late stage. The main copper- gold mineralization occurs in the early and middle stages, which is related to the quartz monzodiorite and dacitic rocks. Pyrite, chalcopyrite and bornite were continuously crystallized from early to late stage. The early stage of pyrite, chalcopyrite, bornite, molybdenite and sphalerite were replaced by middle stage of minerals. The middle stage minerals are sphalerite, tennantite, tetrahedrite, chalcocite, covellite, eugenite, galena, electrum, and gold, those are dominantly occur in the quartz monzodiorite. Additional pyrite, bornite and chalcopyrite were also deposited during this stage. In the late stage, pyrite, chalcopyrite and bornite are dominantly occurs as veins, veinlets and fracture

  20. Tellurides, selenides and Bi-mineral assemblages from the Río Narcea Gold Belt, Asturias, Spain: genetic implications in Cu-Au and Au skarns

    Science.gov (United States)

    Cepedal, A.; Fuertes-Fuente, M.; Martín-Izard, A.; González-Nistal, S.; Rodríguez-Pevida, L.

    2006-07-01

    Gold ores in skarns from the Río Narcea Gold Belt are associated with Bi-Te(-Se)-bearing minerals. These mineral assemblages have been used to compare two different skarns from this belt, a Cu-Au skarn (calcic and magnesian) from the El Valle deposit, and a Au-reduced calcic skarn from the Ortosa deposit. In the former, gold mineralization occurs associated with Cu-(Fe)-sulfides (chalcopyrite, bornite, chalcocite-digenite), commonly in the presence of magnetite. Gold occurs mainly as native gold and electrum. Au-tellurides (petzite, sylvanite, calaverite) are locally present; other tellurides are hessite, clausthalite and coloradoite. The Bi-bearing minerals related to gold are Bi-sulfosalts (wittichenite, emplectite, aikinite, bismuthinite), native bismuth, and Bi-tellurides and selenides (tetradymite, kawazulite, tsumoite). The speciation of Bi-tellurides with Bi/Te(Se + S) ≤ 1, the presence of magnetite and the abundance of precious metal tellurides and clausthalite indicate fO2 conditions within the magnetite stability field that locally overlap the magnetite-hematite buffer. In Ortosa deposit, gold essentially occurs as native gold and maldonite and is commonly related to pyrrhotite and to the replacement of löllingite by arsenopyrite, indicating lower fO2 conditions for gold mineralization than those for El Valle deposit. This fact is confirmed by the speciation of Bi-tellurides and selenides (hedleyite, joséite-B, joséite-A, ikunolite-laitakarite) with Bi/Te(+ Se + S) ≥ 1.

  1. [Reiner Nürnberg, Ekkehard Höxtermann, Martina Voigt. Elisabeth Schiemann 1881-1972. Vom AußBruch der Genetik und der Frauen in den UmBrüchen des 20. Jahrhunderts] / Monika von Hirschheydt

    Index Scriptorium Estoniae

    Hirschheydt, Monika von

    2015-01-01

    Arvustus: Nürnberg, Reiner, Höxtermann, Ekkehard, Voigt, Martina. Elisabeth Schiemann 1881-1972. Vom AußBruch der Genetik und der Frauen in den UmBrüchen des 20. Jahrhunderts. Beiträge eines Symposiums zum 200. Gründungsjubiläum der Humboldt-Universität Berlin. Rangsdorf: Basilisken-Presse 2014

  2. Radiochemical neutron activation analysis for 36 elements in geological material: Au, Ag, Bi, Br, Cd, Cs, Ge, In, Ir, Ni, Os, Pd, Rb, Re, Sb, Se, Sn, Te, Tl, U, and Zn as well as Sc, Y, and REE

    Energy Technology Data Exchange (ETDEWEB)

    Anders, E; Wolf, R; Morgan, J W; Ebihara, M; Woodrow, A B; Janssens, M J; Hertogen, J

    1988-01-01

    In lunar and terrestrial rocks and in meteorites, the radiochemical neutron activation method decribed here enables determination of the 21 trace and ultratrace elements Ag, Au, Bi, Br, Cd, Cs, Ga, Ge, In, Ir, Ni, Os, Pd, Rb, Re, Sb, Se, Te, Tl, U, Zn, as well as 13 rare earth elements (REE), Sc and Y. Materials, techniques and procedures are discussed. 81 refs.

  3. Adsorption of CO and O{sub 2} on Au{sub m}Cu{sub n} clusters: First principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Kadioglu, Y. [Department of Physics, Adnan Menderes University, 09100 Aydn (Turkey); Gökoğlu, G. [Department of Physics, Karabük University, 78050 Karabük (Turkey); Üzengi Aktürk, O., E-mail: ouzengi@adu.edu.tr [Department of Physics, Adnan Menderes University, 09100 Aydn (Turkey)

    2015-03-31

    The adsorption of CO and O{sub 2} molecules on Au{sub n} (n = 2–5), Cu{sub n}(n = 2–5), and Au{sub m}Cu{sub n} (m = 1, 2, 3; 1 ≤ n ≤ 6) clusters is investigated in the framework of density functional theory. The equilibrium atomic geometry and electronic structure of each cluster are determined. It is found that Au{sub n} (n = 2–5) clusters show strong reactivity toward CO, while they do not bind to molecular oxygen. High adsorption energy values can be obtained for odd number of Cu{sub n} clusters for both CO and O{sub 2} adsorptions. Cu top site is energetically preferred for the adsorption of both CO and O{sub 2} molecules in Au{sub m}Cu{sub n} clusters. The results of electronic density of states show an sp hybridization between Cu and O atoms in O{sub 2} adsorbed Au{sub m}Cu{sub n} clusters. This interaction plays a major role in their binding. The highest occupied molecular orbital and the lowest unoccupied molecular orbital energy gap values and charge density differences are presented. There are charge transfers from s and d orbital electrons of Cu to p orbitals of C and of O atoms. It is observed that O{sub 2} adsorption on some clusters can induce half metallicity which is an ideal property for possible applications in spintronics. - Highlights: • A strong binding is observed between CO/O{sub 2} molecules and AumCun clusters. • The energy gap values exhibit odd–even oscillation in CO adsorbed AumCun clusters. • Au{sub 2}Cu{sub 2} has the highest energy gap value indicating the highest electronic stability. • It is observed that O{sub 2} adsorption on some clusters can induce half metallicity.

  4. Transition metal complexes with thiosemicarbazide-based ligands. Part 60. Reactions of copper(II) bromide with pyridoxal S-methylisothiosemicarbazone (PLITSC). Crystal structure of [Cu(PLITSC–H)H2O]Br·H2O

    National Research Council Canada - National Science Library

    Vukadin M Leovac; Ljiljana S Vojinović-Ješić; Sonja A Ivković; Marko V Rodić; Ljiljana S Jovanović; Berta Holló; Katalin Mészáros Szécsényi

    2014-01-01

    The synthesis and structural characterization of a square-planar copper(II) complex with pyridoxal S-methylisothiosemicarbazone (PLITSC) of the formula [Cu(PLITSC–H)H2O]Br·H2O (1) as the first Cu(II...

  5. Plasmon resonance enhanced photocatalysis under visible light with Au/Cu-TiO2 nanoparticles: Removal Cr (VI) from water as a case of study

    KAUST Repository

    Gondal, M. A.

    2013-12-01

    Gold modified copper doped titania (Au/Cu:TiO2) nanoparticles were synthesized by a modified sol gel method and characterized using XRD, optical and TEM based techniques. The as-prepared material contained anatase phase particles with quasi-spherical morphology, showing enhanced absorption in the visible region and low photoluminescence emission intensity. Photocatalytic reduction of Cr (VI) in aqueous suspension with the Au/Cu:TiO2catalyst under 532 nm laser radiation and a visible broad band lamp source yielded 96% and 45% removal, respectively, without any additives. The enhanced photocatalytic activity can be attributed to the improved plasmonic effect due to gold modification and the expanded visible absorption due to copper doping. Moreover a comparative study of the material properties and catalytic activity of TiO2, Cu-TiO2and Au/Cu-TiO2 was carried out. © 2013 by American Scientific Publishers.

  6. Interacting spin-1/2 tetrahedral system Cu2Te2O5X2 (X = Cl, Br)

    DEFF Research Database (Denmark)

    Jensen, Jens

    2009-01-01

    Magnetic ordering and excitations of Cu2Te2O5Cl2 are analyzed in terms of a tetramerized spin model for the tetrahedral Cu clusters of spin 1/2. The mean-field model is able to account for the main properties of the incommensurable magnetic structure observed by Zaharko et al. [Phys. Rev. B 73, 0...

  7. Impedance investigation of the highly efficient polymer solar cells with composite CuBr2/MoO3 hole transport layer.

    Science.gov (United States)

    Li, Zhiqi; Guo, Wenbin; Liu, Chunyu; Zhang, Xinyuan; Li, Shujun; Guo, Jiaxin; Zhang, Liu

    2017-08-09

    Developing an air-stable, low-cost, non-toxic, and high-transparency charge buffer layer is a critical strategy to achieve the high photoelectric conversion efficiency of polymer photovoltaic cells. This paper reports the remarkable improvement of device performance by employing a combination of copper bromide (CuBr2) and molybdenum trioxide (MoO3) (CuBr2/MoO3) as the hole transport layer (HTL) of inverted-type polymer solar cells (PSCs). The bulk transport processes and resistive capacitance elements in the operating PTB7:PC71BM bulk heterojunction PSCs were characterized using impedance spectroscopy. The impedance response was modeled using two equivalent circuital models, which are the general transmission line circuit (GTLC) model and the electrochemical polarization model. The effective carrier lifetime, conductivity, and mobility for both devices were extracted from the models. The improved hole transport at the anode and the efficient electron transport blocking decreased interface recombination and contact resistance, resulting in improved power conversion efficiency (PCE) values ranging from 7.30% to 9.56%. These results suggest that quantitative interpretation and modeling of the impedance spectroscopy results provide an effective way to unravel the operating mechanism of photovoltaic devices.

  8. Ultrasensitive amperometric immunosensor for PSA detection based on Cu2O@CeO2-Au nanocomposites as integrated triple signal amplification strategy.

    Science.gov (United States)

    Li, Faying; Li, Yueyun; Feng, Jinhui; Dong, Yunhui; Wang, Ping; Chen, Lei; Chen, Zhiwei; Liu, Hui; Wei, Qin

    2017-01-15

    In this work, a novel label-free electrochemical immunosensor was developed for the quantitative detection of prostate specific antigen (PSA). To this end, the amino functionalized cuprous oxide @ ceric dioxide (Cu2O@CeO2-NH2) core-shell nanocomposites were prepared to bond gold nanoparticles (Au NPs) by constructing stable Au-N bond between Au NPs and -NH2. Because the synergetic effect presents in Cu2O@CeO2 core-shell loaded with Au NPs (Cu2O@CeO2-Au), it shows better electrocatalytic activity towards the reduction of hydrogen peroxide (H2O2) than single Cu2O, Au NPs and Cu2O@CeO2. Featured by large specific surface area, good biocompatibility and good electrochemical properties which can greatly improve the electronic transmission rate, Cu2O@CeO2-Au was used as transducing materials to achieve efficiently capture antibodies and triple signal amplification of the proposed immunosensor. Under the optimal conditions, the proposed immunosensor exhibited a wide linear range from 0.1pg/mL to 100ng/mL with a low detection limit of 0.03pg/mL (S/N=3). Furthermore, the proposed label-free immunosensor has been used to determine PSA in human serum with satisfactory results. Meanwhile, it displayed good reproducibility, acceptable selectivity, and long-term stability, which had promising application in bioassay analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Écrire pour vivre, vivre pour écrire: un récit autobiographique au Brésil

    Directory of Open Access Journals (Sweden)

    Maria Luisa Scaramella

    2010-02-01

    Full Text Available Cet article traite du rôle de l’écriture autobiografique dans la vie de Maura Lopes Cançado. Maura a écrit un livre, l´Hospice c´est Dieu, espèce de journal intime autobiographique publiée en 1965 au Brésil. Maura commence sa carrière en écrivant des contes pour le Jornal do Brasil, en 1958, dans le supplément littéraire. Son désir pour être reconnue donne lieu à des crises de nerfs, le conduisant à s´interner en hopitaux psychiatriques. Son livre est le fruit de ses nombreux internements, il fournit un portrait de sa condition: la patiente qui subit les pratiques d´une institution psychiatrique violente et décadente; l´individu qui puise dans l´écriture autobiographique son lien le plus profond avec la vie, son fil d´Ariane, qui le tire du labyrinthe. Cette écriture marquée par la souffrance, sert de pont entre Maura et le monde. Si écrire est le fil qui le relie à la vie, à l’autre, à la société, à mesure que Maura s´éloigne de l´écriture, son histoire devient tragique. Le je et l’autre s´éloignent.

  10. Ab Initio Investigation on Structural, Elastic and Electronic Properties of η-Phase Cu4.5Ni1Au0.5Sn5 and Cu5Ni1Sn4.5In0.5 Intermetallic Compounds

    Science.gov (United States)

    Li, Xuezheng; Ma, Yong; Zhou, Wei; Wu, Ping

    2017-10-01

    The structural, elastic and electronic properties of quaternary intermetallic compounds η-Cu4.5Ni1Au0.5Sn5 and η-Cu5Ni1Sn4.5In0.5 are investigated by an ab initio method. The calculated heat of formation determines preferential occupancy sites for Ni, Au and In atoms which lead to thermodynamically stable compounds. Variation of lattice constants reveals that the change of atomic bonding has a directional discrepancy in η-Cu4.5Ni1Au0.5Sn5; the polycrystalline moduli obtained from single-crystal elastic stiffness show an increase after both Ni/Au and Ni/In additions. Also, the anisotropy of Young's modulus and shear modulus is significantly weakened in η-Cu4.5Ni1Au0.5Sn5. The density of states and maps of charge density distribution suggest that the atomic bonding in the quaternary intermetallic compounds is strengthened by the addition of Ni and Au but weakened by the addition of In.

  11. Fabrication and characterization of copper oxide (CuO)–gold (Au)–titania (TiO{sub 2}) and copper oxide (CuO)–gold (Au)–indium tin oxide (ITO) nanowire heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Chopra, Nitin, E-mail: nchopra@eng.ua.edu [Metallurgical and Materials Engineering, Center for Materials for Information Technology (MINT), Box 870202, The University of Alabama, Tuscaloosa, AL 35487 (United States); Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487 (United States); Shi, Wenwu [Metallurgical and Materials Engineering, Center for Materials for Information Technology (MINT), Box 870202, The University of Alabama, Tuscaloosa, AL 35487 (United States); Lattner, Andrew [NSF-REH, Northridge High School, Tuscaloosa, AL 35487 (United States)

    2014-10-15

    Nanoscale heterostructures composed of standing copper oxide nanowires decorated with Au nanoparticles and shells of titania and indium tin oxide were fabricated. The fabrication process involved surfactant-free and wet-chemical nucleation of gold nanoparticles on copper oxide nanowires followed by a line-of-sight sputtering of titania or indium tin oxide. The heterostructures were characterized using high resolution electron microscopy, diffraction, and energy dispersive spectroscopy. The interfaces, morphologies, crystallinity, phases, and chemical compositions were analyzed. The process of direct nucleation of gold nanoparticles on copper oxide nanoparticles resulted in low energy interface with aligned lattice for both the components. Coatings of polycrystalline titania or amorphous indium tin oxide were deposited on standing copper oxide nanowire–gold nanoparticle heterostructures. Self-shadowing effect due to standing nanowire heterostructures was observed for line-of-sight sputter deposition of titania or indium tin oxide coatings. Finally, the heterostructures were studied using Raman spectroscopy and ultraviolet–visible spectroscopy, including band gap energy analysis. Tailing in the band gap energy at longer wavelengths (or lower energies) was observed for the nanowire heterostructures. - Highlights: • Heterostructures comprised of CuO nanowires coated with Au nanoparticles. • Au nanoparticles exhibited nearly flat and low energy interface with nanowire. • Heterostructures were further sputter-coated with oxide shell of TiO{sub 2} or ITO. • The process resulted in coating of polycrystalline TiO{sub 2} and amorphous ITO shell.

  12. Retrieval of Au, Ag, Cu precious metals coupled with electric energy production via an unconventional coupled redox fuel cell reactor.

    Science.gov (United States)

    Zhang, Hui-Min; Fan, Zheng; Xu, Wei; Feng, Xiao; Wu, Zu-Cheng

    2017-09-15

    The recovery of heavy metals from aqueous solutions or e-wastes is of upmost importance. Retrieval of Au, Ag, and Cu with electricity generation through building an ethanol-metal coupled redox fuel cells (CRFCs) is demonstrated. The cell was uniquely assembled on PdNi/C anode the electro-oxidation of ethanol takes place to give electrons and then go through the external circuit reducing metal ions to metallic on the cathode, metals are recovered. Taking an example of removal of 100mgL-1 gold in 0.5M HAc-NaAc buffer solution as the catholyte, 2.0M ethanol in 1.0M alkaline solution as the anolyte, an open circuit voltage of 1.4V, more than 96% of gold removal efficiency in 20h, and equivalent energy production of 2.0kWhkg-1 of gold can be readily achieved in this system. When gold and copper ions coexist, it was confirmed that metallic Cu is formed on the cathodic electrode later than metallic Au formation by XPS analysis. Thus, this system can achieve step by step electrodeposition of gold and copper while the two metal ions coexisting. This work develops a new approach to retrieve valuable metals from aqueous solution or e-wastes. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Superparamagnetism and different growth mechanisms of Co/Au(111) and Co/Cu(111) multilayers grown by molecular-beam epitaxy

    Science.gov (United States)

    Xu, J.; Howson, M. A.; Hickey, B. J.; Greig, D.; Kolb, E.; Veillet, P.; Wiser, N.

    1997-01-01

    The magnetization of Co/Au(111) and Co/Cu(111) multilayers grown by molecular-beam epitaxy has been measured. For ultrathin Co layers, superparamagnetic behavior is observed, very similar to that reported previously for granular samples. For somewhat thicker Co layers, hysteresis effects occur, indicating the absence of superparamagnetism. The clear transition seen between these two modes of behavior is attributed to the growth of the Co particles from very small superparamagnetic clusters to larger islands and ultimately to a film, as the thickness of the Co layers is increased. Different magnetic properties are found for the Co/Au(111) and the Co/Cu(111) systems during the transition from granular to continuous layers. An investigation by reflection high-energy electron diffraction suggests that this difference is mainly due to the different growth modes of Co on Au(111) and on Cu(111).

  14. Comparative investigation of the coupled-tetrahedra quantum spin systems Cu{sub 2}Te{sub 2}O{sub 5}X{sub 2}, X = Cl, Br and Cu{sub 4}Te{sub 5}O{sub 12}Cl{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Valenti, R. [Institut fuer Theoretische Physik, Universitaet Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt (Germany)], E-mail: valenti@itp.uni-frankfurt.de; Saha-Dasgupta, T. [S.N. Bose National Centre for Basic Sciences, JD Block, Sector 3, Salt Lake City, Kolkata 700 098 (India); Jeschke, H.O. [Institut fuer Theoretische Physik, Universitaet Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt (Germany); Rahaman, B. [S.N. Bose National Centre for Basic Sciences, JD Block, Sector 3, Salt Lake City, Kolkata 700 098 (India); Rosner, H. [MPI-CPS, Noethnitzer Strasse 40, 01187 Dresden (Germany); Lemmens, P. [IPCM, TU Braunschweig, Mendelssohnstrasse 3, 38106 Braunschweig (Germany); Takagi, R.; Johnsson, M. [Department of Inorganic Chemistry, Stockholm University, S-10691 Stockholm (Sweden)

    2007-09-01

    We present a comparative study of the coupled-tetrahedra quantum spin systems Cu{sub 2}Te{sub 2}O{sub 5}X{sub 2}, X = Cl, Br (Cu-2252(X)) and the newly synthesized Cu{sub 4}Te{sub 5}O{sub 12}Cl{sub 4} (Cu-45124(Cl)) based on ab initio density functional theory calculations. The magnetic behavior of Cu-45124(Cl) with a phase transition to an ordered state at a lower critical temperature T{sub c} = 13.6 K than in Cu-2252(Cl) (T{sub c} = 18.2 K) can be well understood in terms of the modified interaction paths. We identify the relevant structural changes between the two systems and discuss the hypothetical behavior of the not yet synthesized Cu-45124(Br) with an ab initio relaxed structure using Car-Parrinello molecular dynamics.

  15. Concealed basalt-matrix diatremes with Cu-Au-Ag-(Mo)-mineralized xenoliths, Santa Cruz Porphyry Cu-(Mo) System, Pinal County, Arizona

    Science.gov (United States)

    Vikre, Peter; Graybeal, Frederick T.; Koutz, Fleetwood R.

    2014-01-01

    The Santa Cruz porphyry Cu-(Mo) system near Casa Grande, Arizona, includes the Sacaton mine deposits and at least five other concealed, mineralized fault blocks with an estimated minimum resource of 1.5 Gt @ 0.6% Cu. The Late Cretaceous-Paleocene system has been dismembered and rotated by Tertiary extension, partially eroded, and covered by Tertiary-Quaternary basin-fill deposits. The mine and mineralized fault blocks, which form an 11 km (~7 miles) by 1.6 km (~1 mile) NE-SW–trending alignment, represent either pieces of one large deposit, several deposits, or pieces of several deposits. The southwestern part of the known system is penetrated by three or more diatremes that consist of heterolithic breccia pipes with basalt and clastic matrices, and subannular tuff ring and maar-fill sedimentary deposits associated with vents. The tephra and maar-fill deposits, which are covered by ~485 to 910 m (~1,600–3,000 ft) of basin fill, lie on a mid-Tertiary erosion surface of Middle Proterozoic granite and Late Cretaceous porphyry, which compose most xenoliths in pipes and are the host rocks of the system. Some igneous xenoliths in the pipes contain bornite-chalcopyrite-covellite assemblages with hypogene grades >1 wt % Cu, 0.01 ounces per ton (oz/t) Au, 0.5 oz/t Ag, and small amounts of Mo (fluid which, based on fluid inclusion populations in mineralized xenoliths, was saline water and CO2. The large vertical extent (~600 m; ~2,000 ft) of basalt matrix in pipes, near-paleosurface matrix vesiculation, and plastically deformed basalt lapilli indicates that diatreme eruptions were predominantly phreatic.Diatreme xenoliths represent crustal stratigraphy and, as in the Santa Cruz system, provide evidence of concealed mineral resources that can guide exploration drilling through cover. Vectors to the source of bornite-dominant xenoliths containing >1% Cu and significant Au and Ag could be determined by refinement of breccia pipe geometries, by reassembly of mineralized fault

  16. $\\phi$ meson production in the forward/backward rapidity region in Cu$+$Au collisions at $\\sqrt{s_{NN}}=200$ GeV

    CERN Document Server

    Adare, A; Ajitanand, N N; Akiba, Y; Akimoto, R; Alexander, J; Alfred, M; Al-Ta'ani, H; Andrews, K R; Angerami, A; Aoki, K; Apadula, N; Appelt, E; Aramaki, Y; Armendariz, R; Asano, H; Aschenauer, E C; Atomssa, E T; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Bai, X; Bandara, N S; Bannier, B; Barish, K N; Bassalleck, B; Basye, A T; Bathe, S; Baublis, V; Baumann, C; Baumgart, S; Bazilevsky, A; Beaumier, M; Beckman, S; Belmont, R; Ben-Benjamin, J; Bennett, R; Berdnikov, A; Berdnikov, Y; Black, D; Blau, D S; Bok, J S; Boyle, K; Brooks, M L; Broxmeyer, D; Bryslawskyj, J; Buesching, H; Bumazhnov, V; Bunce, G; Butsyk, S; Campbell, S; Castera, P; Chen, C -H; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choi, S; Choudhury, R K; Christiansen, P; Chujo, T; Chvala, O; Cianciolo, V; Citron, Z; Cole, B A; del Valle, Z Conesa; Connors, M; Cronin, N; Crossette, N; Csanád, M; Csörgő, T; Dairaku, S; Danley, D; Datta, A; Daugherity, M S; David, G; Dayananda, M K; DeBlasio, K; Dehmelt, K; Denisov, A; Deshpande, A; Desmond, E J; Dharmawardane, K V; Dietzsch, O; Ding, L; Dion, A; Diss, P B; Do, J H; Donadelli, M; D'Orazio, L; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; Efremenko, Y V; Engelmore, T; Enokizono, A; En'yo, H; Esumi, S; Eyser, K O; Fadem, B; Feege, N; Fields, D E; Finger, M; Jr., \\,; Fleuret, F; Fokin, S L; Frantz, J E; Franz, A; Frawley, A D; Fukao, Y; Fusayasu, T; Gainey, K; Gal, C; Gallus, P; Garg, P; Garishvili, A; Garishvili, I; Ge, H; Giordano, F; Glenn, A; Gong, X; Gonin, M; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Perdekamp, M Grosse; Gu, Y; Gunji, T; Guo, L; Guragain, H; Gustafsson, H -Å; Hachiya, T; Haggerty, J S; Hahn, K I; Hamagaki, H; Hamblen, J; Hamilton, H F; Han, R; Han, S Y; Hanks, J; Harper, C; Hasegawa, S; Haseler, T O S; Hashimoto, K; Haslum, E; Hayano, R; He, X; Hemmick, T K; Hester, T; Hill, J C; Hollis, R S; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hori, Y; Hornback, D; Hoshino, T; Hotvedt, N; Huang, J; Huang, S; Ichihara, T; Ichimiya, R; Iinuma, H; Ikeda, Y; Imai, K; Imazu, Y; Inaba, M; Iordanova, A; Isenhower, D; Ishihara, M; Isinhue, A; Issah, M; Ivanishchev, D; Iwanaga, Y; Jacak, B V; Jeon, S J; Jezghani, M; Jia, J; Jiang, X; John, D; Johnson, B M; Jones, T; Joo, K S; Jouan, D; Jumper, D S; Kamin, J; Kanda, S; Kaneti, S; Kang, B H; Kang, J H; Kang, J S; Kapustinsky, J; Karatsu, K; Kasai, M; Kawall, D; Kazantsev, A V; Kempel, T; Key, J A; Khachatryan, V; Khandai, P K; Khanzadeev, A; Kijima, K M; Kim, B I; Kim, C; Kim, D J; Kim, E -J; Kim, G W; Kim, M; Kim, Y -J; Kim, Y K; Kimelman, B; Kinney, E; Kiss, Á; Kistenev, E; Kitamura, R; Klatsky, J; Kleinjan, D; Kline, P; Koblesky, T; Kochenda, L; Kofarago, M; Komkov, B; Konno, M; Koster, J; Kotchetkov, D; Kotov, D; Král, A; Krizek, F; Kunde, G J; Kurita, K; Kurosawa, M; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, D M; Lee, G H; Lee, J; Lee, K B; Lee, K S; Lee, S; Lee, S H; Lee, S R; Leitch, M J; Leite, M A L; Leitgab, M; Lewis, B; Li, X; Lim, S H; Levy, L A Linden; Liu, H; Liu, M X; Love, B; Lynch, D; Maguire, C F; Makdisi, Y I; Makek, M; Manion, A; Manko, V I; Mannel, E; Mao, Y; Maruyama, T; Masui, H; McCumber, M; McGaughey, P L; McGlinchey, D; McKinney, C; Means, N; Meles, A; Mendoza, M; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Miki, K; Milov, A; Mishra, D K; Mitchell, J T; Miyachi, Y; Miyasaka, S; Mizuno, S; Mohanty, A K; Mohapatra, S; Montuenga, P; Moon, H J; Moon, T; Morino, Y; Morreale, A; Morrison, D P; Moskowitz, M; Motschwiller, S; Moukhanova, T V; Murakami, T; Murata, J; Mwai, A; Nagae, T; Nagamiya, S; Nagashima, K; Nagle, J L; Naglis, M; Nagy, M I; Nakagawa, I; Nakagomi, H; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nattrass, C; Netrakanti, P K; Newby, J; Nguyen, M; Nihashi, M; Niida, T; Nishimura, S; Nouicer, R; Novak, T; Novitzky, N; Nyanin, A S; Oakley, C; O'Brien, E; Ogilvie, C A; Oide, H; Oka, M; Okada, K; Koop, J D Orjuela; Osborn, J D; Oskarsson, A; Ouchida, M; Ozawa, K; Pak, R; Pantuev, V; Papavassiliou, V; Park, B H; Park, I H; Park, J S; Park, S; Park, S K; Pate, S F; Patel, L; Patel, M; Pei, H; Peng, J -C; Pereira, H; Perepelitsa, D V; Perera, G D N; Peressounko, D Yu; Perry, J; Petti, R; Pinkenburg, C; Pinson, R; Pisani, R P; Proissl, M; Purschke, M L; Qu, H; Rak, J; Ramson, B J; Ravinovich, I; Read, K F; Reygers, K; Reynolds, D; Riabov, V; Riabov, Y; Richardson, E; Rinn, T; Riveli, N; Roach, D; Roche, G; Rolnick, S D; Rosati, M; Rosendahl, S S E; Rowan, Z; Rubin, J G; Ryu, M S; Sahlmueller, B; Saito, N; Sakaguchi, T; Sako, H; Samsonov, V; Sano, S; Sarsour, M; Sato, S; Sato, T; Savastio, M; Sawada, S; Schaefer, B; Schmoll, B K; Sedgwick, K; Seele, J; Seidl, R; Sekiguchi, Y; Sen, A; Seto, R; Sett, P; Sexton, A; Sharma, D; Shaver, A; Shein, I; Shibata, T -A; Shigaki, K; Shim, H H; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, B K; Singh, C P; Singh, V; Skolnik, M; Slunečka, M; Snowball, M; Sodre, T; Solano, S; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Stankus, P W; Steinberg, P; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Stone, M R; Sugitate, T; Sukhanov, A; Sumita, T; Sun, J; Sziklai, J; Takagui, E M; Takahara, A; Taketani, A; Tanabe, R; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tennant, E; Themann, H; Thomas, D; Tieulent, R; Timilsina, A; Todoroki, T; Togawa, M; Tomášek, L; Tomášek, M; Torii, H; Towell, C L; Towell, R; Towell, R S; Tserruya, I; Tsuchimoto, Y; Utsunomiya, K; Vale, C; van Hecke, H W; Vargyas, M; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Virius, M; Vossen, A; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Wei, R; Wessels, J; Whitaker, S; White, A S; White, S N; Winter, D; Wolin, S; Woody, C L; Wright, R M; Wysocki, M; Xia, B; Xue, L; Yalcin, S; Yamaguchi, Y L; Yang, R; Yanovich, A; Ying, J; Yokkaichi, S; Yoo, J H; Yoo, J S; Yoon, I; You, Z; Young, G R; Younus, I; Yu, H; Yushmanov, I E; Zajc, W A; Zelenski, A; Zhou, S; Zou, L

    2015-01-01

    The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) has measured $\\phi$ meson production and its nuclear modification in asymmetric Cu$+$Au heavy-ion collisions at $\\sqrt{s_{NN}}=200$ GeV at both forward Cu-going direction ($1.2Au-going direction ($-2.2Cu-going direction compared to the Au-going direction. Additionally, the nuclear-modification factor in Cu$+$Au collisions averaged over all centrality is measured to be similar to the previous PHENIX result in $d$$+$Au collisions for these rapidities.

  17. Modulation of luminescence by subtle anion-cation and anion-π interactions in a trigonal Au(I)···Cu(I) complex.

    Science.gov (United States)

    Chen, Kelly; Strasser, Christoph E; Schmitt, Jennifer C; Shearer, Jason; Catalano, Vincent J

    2012-02-06

    The trigonally coordinated [AuCu(PPh(2)py)(3)](BF(4))(2) (1) crystallizes in two polymorphs and a pseudopolymorph, each of which contains a trigonally coordinated cation with short Au(I)-Cu(I) separations of ∼2.7 Å. Under UV illumination, these crystals luminesce different colors ranging from blue to yellow. The structures of these cations are nearly superimposable, and the primary difference resides in the relative placement of the anions and solvate molecules. As confirmed by time-dependent density functional theory calculations, it is these interactions that are responsible for the differential emission properties.

  18. Crystal structure, Hirshfeld surface, physicochemical, thermal and DFT studies of (N1E, N2E)-N1,N2-bis((5-bromothiophen-2-yl)methylene)ethane-1,2-diamine N2S2 ligand and its [CuBr(N2S2)]Br complex

    Science.gov (United States)

    Warad, Ismail; Al-Demeri, Yasmin; Al-Nuri, Mohammed; Shahwan, Said; Abdoh, Muneer; Naveen, Shivalingegowda; Lokanath, Neartur Krishnappagowda; Mubarak, Mohammad S.; Ben Hadda, Taibi; Mabkhot, Yahia N.

    2017-08-01

    A new tetradentate N2S2 Schiff base ligand derived from 5-bromothiophene-2-carbaldehyde and its [CuBr(N2S2)]Br complex were synthesized in good yield. FT-IR was investigated to monitor the condensation reaction during the ligand synthesis process. The ligand, N2S2, and its complex, [CuBr(N2S2)]Br, complex have been characterized with the aid of several spectroscopic techniques such as UV-vis., MS, FT-IR, EA, EDS, NMR (for N2S2), as well as by thermal (TG/DTG) analysis. In addition, cyclic voltammetry has been employed to examine the redox behavior of [CuBr(N2S2)]Br complex in N,N'-dimethylformamide (DMF) containing 0.10 M tetra-n-butylammonium perchlorate (TBAP). The anti-conformation EE isomer of the ligand (N2S2) was confirmed by means of X-ray crystallography; ligand crystallizes in to the monoclinic P21/c space group. N2S2 ligand was subjected to DFT-theoretical calculations and results are consistent with the experimental chemical analysis.

  19. Integrated logic gate for fluorescence turn-on detection of histidine and cysteine based on Ag/Au bimetallic nanoclusters-Cu²⁺ ensemble.

    Science.gov (United States)

    Sun, Jian; Yang, Fan; Zhao, Dan; Chen, Chuanxia; Yang, Xiurong

    2015-04-01

    By means of employing 11-mercaptoundecanoic acid (11-MUA) as a reducing agent and protecting ligand, we present straightforward one-pot preparation of fluorescent Ag/Au bimetallic nanoclusters (namely AgAuNCs@11-MUA) from AgNO3 and HAuCl4 in alkaline aqueous solution at room temperature. It is found that the fluorescence of AgAuNCs@11-MUA has been selectively quenched by Cu(2+) ions, and the nonfluorescence off-state of the as-prepared AgAuNCs@11-MUA-Cu(2+) ensemble can be effectively switched on upon the addition of histidine and cysteine. By incorporating Ni(2+) ions and N-ethylmaleimide, this phenomenon is further exploited as an integrated logic gate and a specific fluorescence turn-on assay for selectively and sensitively sensing histidine and cysteine has been designed and established based on the original noncovalent AgAuNCs@11-MUA-Cu(2+) ensemble. Under the optimal conditions, histidine and cysteine can be detected in the concentration ranges of 0.25-9 and 0.25-7 μM; besides, the detection limits are found to be 87 and 111 nM (S/N = 3), respectively. Furthermore, we demonstrate that the proposed AgAuNCs@11-MUA-based fluorescent assay can be successfully utilized for biological fluids sample analysis.

  20. Facile synthesis, pharmacokinetic and systemic clearance evaluation, and positron emission tomography cancer imaging of ⁶⁴Cu-Au alloy nanoclusters.

    Science.gov (United States)

    Zhao, Yongfeng; Sultan, Deborah; Detering, Lisa; Luehmann, Hannah; Liu, Yongjian

    2014-11-21

    Gold nanoparticles have been widely used for oncological applications including diagnosis and therapy. However, the non-specific mononuclear phagocyte system accumulation and potential long-term toxicity have significantly limited clinical translation. One strategy to overcome these shortcomings is to reduce the size of gold nanoparticles to allow renal clearance. Herein, we report the preparation of (64)Cu alloyed gold nanoclusters ((64)CuAuNCs) for in vivo evaluation of pharmacokinetics, systemic clearance, and positron emission tomography (PET) imaging in a mouse prostate cancer model. The facile synthesis in acqueous solution allowed precisely controlled (64)Cu incorporation for high radiolabeling specific activity and stability for sensitive and accurate detection. Through surface pegylation with 350 Da polyethylene glycol (PEG), the (64)CuAuNCs-PEG350 afforded optimal biodistribution and significant renal and hepatobiliary excretion. PET imaging showed low non-specific tumor uptake, indicating its potential for active targeting of clinically relevant biomarkers in tumor and metastatic organs.

  1. A bi-overlayer type plasmonic photocatalyst consisting of mesoporous Au/TiO2 and CuO/SnO2 films separately coated on FTO.

    Science.gov (United States)

    Naya, Shin-ichi; Kume, Takahiro; Okumura, Nozomi; Tada, Hiroaki

    2015-07-21

    The principal purpose of this study is to present a new design for preparing highly active immobilized gold nanoparticle-based plasmonic photocatalysts. Gold nanoparticles were loaded on rutile TiO2 particles with a mean size of 80 nm (Au/TiO2) by the deposition precipitation method. The surface of SnO2 particles with a mean size of 100 nm was modified by copper(ii) oxide clusters (CuO/SnO2) with the loading amount (Γ/Cu ions nm(-2)) precisely controlled by the chemisorption-calcination cycle technique. Two mesoporous overlayers of Au/TiO2 and CuO/SnO2 were coated side by side on glass substrates with a fluorine-doped tin oxide film (FTO) using the doctor blade method (Au/mp-TiO2|FTO|CuO/mp-SnO2). As test reactions for assessing the visible-light activity, we carried out gas-phase decomposition of acetaldehyde and liquid-phase oxidation of alcohol. In each reaction, this bi-overlayer type catalyst shows a high level of visible-light activity much exceeding those of Au/TiO2 particles and a Au/mp-TiO2|FTO mono-overlayer type catalyst [J. Phys. Chem. C, 2014, 118, 26887]. To confirm the origin of the striking visible-light activity, we studied the electrocatalytic activity of CuO/mp-SnO2|FTO electrodes for the oxygen reduction reaction (ORR). Both the visible-light activity of Au/mp-TiO2|FTO|CuO/mp-SnO2 and the electrocatalytic activity of CuO/mp-SnO2|FTO for ORR strongly depend on the Γ value. A good positive correlation has been found between the visible-light activities and the electrocatalytic activity for ORR. The striking activity of the present bi-overlayer type catalyst can be attributed to the efficient and long-range charge separation by the vectorial electron transport (Au(oxidation sites) → TiO2→ FTO, SnO2→ CuO(reduction sites)) and the excellent electrocatalytic activity of the CuO clusters.

  2. Insulator-metal transitions induced by electric field and photoirradiation in organic Mott insulator deuterated κ-(BEDT-TTF)2Cu[N(CN)2]Br.

    Science.gov (United States)

    Sabeth, Farzana; Iimori, Toshifumi; Ohta, Nobuhiro

    2012-04-25

    The Mott insulator-metal transition induced by an external stimulus such as electric field, pressure, chemical doping, or photoirradiation has received considerable attention because of the potential use in new optoelectronic functional devices. Here we report an abrupt Mott insulator-metal transition observed as a current jump in a molecular-based Mott insulator, namely, deuterated κ-(BEDT-TTF)(2)Cu[N(CN)(2)]Br, where BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene, upon application of a pulsed voltage of certain magnitude (threshold voltage). Furthermore, the threshold voltage needed for the transition is shown to be reduced by photoirradiation. Thus, the Mott insulator-metal transition can be controlled by a combination of an external electric field and photoirradiation.

  3. Luttinger liquid physics in the spin ladder material CuBr{sub 4}(C{sub 5}H{sub 12}N){sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Klanjsek, M. [Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Laboratoire National des Champs Magnetiques Intenses, CNRS, BP 166, 38042 Grenoble (France); Mayaffre, H. [Laboratoire de Spectrometrie Physique, Universite J. Fourier and UMR5588 CNRS, 38402 Saint Martin d' Heres (France); Berthier, C.; Horvatic, M. [Laboratoire National des Champs Magnetiques Intenses, CNRS, BP 166, 38042 Grenoble (France); Chiari, B.; Piovesana, O. [Dipartimento di Chimica, Universita di Perugia, I-06100 Perugia (Italy); Bouillot, P.; Giamarchi, T. [DPMC-MaNEP, University of Geneva, CH-1211 Geneva (Switzerland); Kollath, C. [Centre de Physique Theorique, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex (France); Orignac, E. [LPENSL CNRS UMR 5672, 69364 Lyon Cedex 07 (France); Citro, R. [Dipartimento di Fisica ' ' E. R. Caianiello' ' , Unita CNISM di Salerno, Universita degli Studi di Salerno, I-84081 Baronissi (Sa) (Italy)

    2010-03-15

    We present a {sup 14}N nuclear magnetic resonance study of a single crystal of CuBr{sub 4}(C{sub 5}H{sub 12}N){sub 2} consisting of weakly coupled spin-1/2 Heisenberg antiferromagnetic ladders. When placed in a magnetic field, such a ladder is theoretically predicted to exhibit a quantum critical Luttinger liquid (LL) behaviour in the gapless phase, i.e. between the two critical fields. Treating ladders as LLs and interaction between them as a perturbation, we are indeed able to fully account for (i) the spin dynamics accessed by measuring the spin-lattice relaxation rate T{sub 1}{sup -} {sup 1}, and for (ii) the phase transition to a 3D ordered phase occurring below 110 mK due to the weak interladder coupling. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  4. Platinum-group element geochemistry of the Forest Reef Volcanics, southeastern Australia: Implications for porphyry Au-Cu mineralisation

    Science.gov (United States)

    Lowczak, Jessica N.; Campbell, Ian H.; Cocker, Helen; Park, Jung-Woo; Cooke, David R.

    2018-01-01

    Platinum-group element concentrations in felsic to intermediate rocks from the Forest Reef Volcanics, Cadia-Neville region, southeastern Australia have been analysed by the Ni-S fire assay-isotope dilution method. The Forest Reef Volcanics are shoshonitic to calc-alkaline in composition and fractionated to produce a wide range of compositions, with MgO varying between 9.7 and 1.8 wt.%. The interest in this suite is that it is coeval with Au-Cu porphyry-style mineralisation in the Cadia mineral district. This study uses PGE geochemistry to determine the timing of sulfide saturation, relative to volatile (ore-fluid) saturation, in the magma that gave rise to the Forest Reef Volcanics and, in turn, to assess how this timing affected the mineralisation potential of the evolving magmatic system. The Forest Reef Volcanics can be subdivided, on the basis of their contrasting PGE geochemistry, into high-Mg (>6.8 wt.% MgO) and low-Mg suites (≤6.8 wt.% MgO). Platinum, Pd and Re concentrations increase in the high-Mg samples, whereas Ir and Ru decrease and Rh concentrations remain steady, with decreasing MgO. The coupled Ir, Ru and Rh depletion is attributed to the partitioning of these elements into magnetite. The rate of Pt and Pd enrichment is not possible by closed-system fractional crystallisation alone, which suggests that the parent magma was replenished by a Pt-Pd-rich melt. In contrast, the PGE concentrations in the low-Mg samples decrease with decreasing MgO indicating the onset of sulfide saturation at 6.8 wt.% MgO, which is confirmed by the presence of spheroidal sulfide inclusions in liquidus crystals (i.e. clinopyroxene, plagioclase, magnetite). The rate of Pd depletion is appreciably less than for any other sulfide saturated felsic system for which data are available. This requires either that the amount of sulfide melt to have precipitated was unusually low, or that the rate of Pd depletion was limited by the mass of silicate melt the sulfide melt reached

  5. Porphyry Cu indicator minerals in till as an exploration tool: Example from the giant pebble porphyry Cu-Au-Mo deposit, Alaska, USA

    Science.gov (United States)

    Kelley, Karen D.; Eppinger, Robert G.; Lang, J.; Smith, Steven M.; Fey, David L.

    2011-01-01

    Porphyry Cu indicator minerals are mineral species in clastic sediments that indicate the presence of mineralization and hydrothermal alteration associated with porphyry Cu and associated skarn deposits. Porphyry Cu indicator minerals recovered from shallow till samples near the giant Pebble Cu-Au-Mo porphyry deposit in SW Alaska, USA, include apatite, andradite garnet, Mn-epidote, visible gold, jarosite, pyrite, and cinnabar. Sulphide minerals other than pyrite are absent from till, most likely due to the oxidation of the till. The distribution of till samples with abundant apatite and cinnabar suggest sources other than the Pebble deposit. With three exceptions, all till samples up-ice of the Pebble deposit contain 40grains/10kg) are in close proximity to smaller porphyry and skarn occurrences in the region. The distribution of Mn-epidote closely mimics the distribution of garnet in the till samples and further supports the interpretation that these minerals most likely reflect skarns associated with the porphyry deposits. All but two till samples, including those up-ice from the deposit, contain some gold grains. However, tills immediately west and down-ice of Pebble contain more abundant gold grains, and the overall number of grains decreases in the down-ice direction. Furthermore, all samples in the immediate vicinity of Pebble contain more than 65% pristine and modified grains compared to mostly re-shaped grains in distal samples. The pristine gold in till reflects short transport distances and/or liberation of gold during in-situ weathering of transported chalcopyrite grains. Jarosite is also abundant (1-2 500 grains/10kg) in samples adjacent to and up to 7 km down-ice from the deposit. Most jarosite grains are rounded and preliminary Ar/Ar dates suggest the jarosite formed prior to glaciation and it implies that a supergene cap existed over Pebble West. Assuming this interpretation is accurate, it suggests a shallow level of erosion of the Pebble deposit by

  6. Transverse Momentum Spectra of KS0 and K*0 at Midrapidity in d + Au, Cu + Cu, and p+p Collisions at sNN=200 GeV

    Directory of Open Access Journals (Sweden)

    Bao-Chun Li

    2015-01-01

    Full Text Available We analyze transverse momentum spectra of KS0 and K*0 at midrapidity in d + Au, Cu + Cu, and p+p collisions at sNN=200 GeV in the formworks of Tsallis statistics and Boltzmann statistics, respectively. Both of them can describe the transverse momentum spectra and extract the thermodynamics parameters of matter evolution in the collisions. The parameters are helpful for us to understand the thermodynamics factors of the particle production.

  7. [X-ray excited luminescence property of ZnS : Au, Cu fine particles synthesized by hydrothermal method].

    Science.gov (United States)

    Xin, Mei; Cao, Wang-He

    2009-08-01

    Highly luminescent ZnS : Au, Cu X-ray phosphor fine particles synthesized by hydrothermal method is reported for the first time and its photoluminescence (PL) and X-ray excited luminescence (XEL) properties were studied in detail. With direct hydrothermal treatment at 200 degrees C for 12 h, the average gain size of samples is about 15 nm; the synthesized sphere-like nanocrystals with well dispersity and narrow gain size distribution show cubic structure. After baking in argon at 1 000 degrees C for 1h the sample agglomerate size is about 1-2 microm and the roughly spherical fine particles show pure hexagonal structure. The PL and XEL spectra of all the samples show a broad emission band and an intense emission band in the range of 400-600 nm. The maximum XEL intensity of sample directly synthesized by hydrothermal treatment was observed when Cu/Zn and Cu/Al were 3 x 10(-5) and 2, respectively. In this condition, the strongest PL emission was observed for the direct synthesized sample being further baked in argon at 900 degrees C for 1 h and the PL peak was centered at about 529 nm. The strongest XEL emission was observed for the direct synthesized sample being further baked in argon at 1 000 degrees C for 1h and the XEL peak was centered at about 445 and 513 nm, respectively. In the meantime, the XEL intensity increased about ten times compared with that directly synthesized without baking. The difference between PL and XEL spectra is due to its different excitation mechanism. The luminescence mechanism and different excitation mechanism of PL and XEL were discussed. The red shift of XEL spectrum with directly synthesized sample was observed with increasing the Cu/Zn. The reason can also be explained by the luminescence mechanism and excitation mechanism of XEL.

  8. Measurement of $K_S^0$ and $K^{*0}$ in $p$$+$$p$, $d$$+$Au, and Cu$+$Cu collisions at $\\sqrt{s_{_{NN}}}=200$ GeV

    CERN Document Server

    Adare, A; Aidala, C; Ajitanand, N N; Akiba, Y; Akimoto, R; Al-Bataineh, H; Alexander, J; Alfred, M; Angerami, A; Aoki, K; Apadula, N; Aphecetche, L; Aramaki, Y; Armendariz, R; Aronson, S H; Asai, J; Asano, H; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Baksay, G; Baksay, L; Baldisseri, A; Bandara, N S; Bannier, B; Barish, K N; Barnes, P D; Bassalleck, B; Basye, A T; Bathe, S; Batsouli, S; Baublis, V; Baumann, C; Bazilevsky, A; Beaumier, M; Beckman, S; Belikov, S; Belmont, R; Bennett, R; Berdnikov, A; Berdnikov, Y; Bhom, J H; Bickley, A A; Black, D; Blau, D S; Boissevain, J G; Bok, J; Bok, J S; Borel, H; Boyle, K; Brooks, M L; Bryslawskyj, J; Buesching, H; Bumazhnov, V; Bunce, G; Butsyk, S; Campbell, S; Caringi, A; Chang, B S; Charvet, J -L; Chen, C -H; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J B; Choudhury, R K; Christiansen, P; Chujo, T; Chung, P; Churyn, A; Chvala, O; Cianciolo, V; Citron, Z; Cleven, C R; Cole, B A; Comets, M P; del Valle, Z Conesa; Connors, M; Constantin, P; Csanád, M; Csörgő, T; Dahms, T; Dairaku, S; Danchev, I; Das, K; Datta, A; Daugherity, M S; David, G; Dayananda, M K; Deaton, M B; DeBlasio, K; Dehmelt, K; Delagrange, H; Denisov, A; d'Enterria, D; Deshpande, A; Desmond, E J; Dharmawardane, K V; Dietzsch, O; Ding, L; Dion, A; Do, J H; Donadelli, M; Drapier, O; Drees, A; Drees, K A; Dubey, A K; Durham, J M; Durum, A; Dutta, D; Dzhordzhadze, V; D'Orazio, L; Edwards, S; Efremenko, Y V; Egdemir, J; Ellinghaus, F; Emam, W S; Engelmore, T; Enokizono, A; En'yo, H; Esumi, S; Eyser, K O; Fadem, B; Feege, N; Fields, D E; Finger, M; Jr., \\,; Fleuret, F; Fokin, S L; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fujiwara, K; Fukao, Y; Fusayasu, T; Gadrat, S; Gal, C; Gallus, P; Garg, P; Garishvili, I; Ge, H; Giordano, F; Glenn, A; Gong, H; Gonin, M; Gosset, J; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Grim, G; Perdekamp, M Grosse; Gu, Y; Gunji, T; Guragain, H; Gustafsson, H -Å; Hachiya, T; Henni, A Hadj; Haegemann, C; Haggerty, J S; Hahn, K I; Hamagaki, H; Hamblen, J; Han, R; Han, S Y; Hanks, J; Harada, H; Hartouni, E P; Haruna, K; Hasegawa, S; Haslum, E; Hayano, R; He, X; Heffner, M; Hemmick, T K; Hester, T; Hiejima, H; Hill, J C; Hobbs, R; Hohlmann, M; Hollis, R S; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hornback, D; Hoshino, T; Huang, S; Ichihara, T; Ichimiya, R; Iinuma, H; Ikeda, Y; Imai, K; Imazu, Y; Inaba, M; Inoue, Y; Iordanova, A; Isenhower, D; Isenhower, L; Ishihara, M; Isobe, T; Issah, M; Isupov, A; Ivanischev, D; Ivanishchev, D; Iwanaga, Y; Jacak, B V; Jeon, S J; Jezghani, M; Jia, J; Jiang, X; Jin, J; Jinnouchi, O; Johnson, B M; Jones, T; Joo, E; Joo, K S; Jouan, D; Jumper, D S; Kajihara, F; Kametani, S; Kamihara, N; Kamin, J; Kaneta, M; Kang, J H; Kang, J S; Kanou, H; Kapustinsky, J; Karatsu, K; Kasai, M; Kawall, D; Kawashima, M; Kazantsev, A V; Kempel, T; Key, J A; Khachatryan, V; Khanzadeev, A; Kihara, K; Kijima, K M; Kikuchi, J; Kim, A; Kim, B I; Kim, C; Kim, D H; Kim, D J; Kim, E; Kim, E -J; Kim, H -J; Kim, M; Kim, Y -J; Kim, Y K; Kinney, E; Kiss, Á; Kistenev, E; Kiyomichi, A; Klatsky, J; Klay, J; Klein-Boesing, C; Kleinjan, D; Kline, P; Koblesky, T; Kochenda, L; Kochetkov, V; Kofarago, M; Komkov, B; Konno, M; Koster, J; Kotchetkov, D; Kotov, D; Kozlov, A; Král, A; Kravitz, A; Kubart, J; Kunde, G J; Kurihara, N; Kurita, K; Kurosawa, M; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, D M; Lee, J; Lee, K B; Lee, K S; Lee, M K; Lee, S H; Lee, T; Leitch, M J; Leite, M A L; Leitgab, M; Lenzi, B; Li, X; Lichtenwalner, P; Liebing, P; Lim, S H; Levy, L A Linden; Liška, T; Litvinenko, A; Liu, H; Liu, M X; Love, B; Lynch, D; Maguire, C F; Makdisi, Y I; Makek, M; Malakhov, A; Malik, M D; Manion, A; Manko, V I; Mannel, E; Mao, Y; Mašek, L; Masui, H; Matathias, F; McCumber, M; McGaughey, P L; McGlinchey, D; McKinney, C; Means, N; Meles, A; Mendoza, M; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Mikeš, P; Miki, K; Miller, A J; Miller, T E; Milov, A; Mioduszewski, S; Mishra, D K; Mishra, M; Mitchell, J T; Mitrovski, M; Miyasaka, S; Mizuno, S; Mohanty, A K; Montuenga, P; Moon, H J; Moon, T; Morino, Y; Morreale, A; Morrison, D P; Moukhanova, T V; Mukhopadhyay, D; Murakami, T; Murata, J; Mwai, A; Nagamiya, S; Nagata, Y; Nagle, J L; Naglis, M; Nagy, M I; Nakagawa, I; Nakagomi, H; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nam, S; Nattrass, C; Netrakanti, P K; Newby, J; Nguyen, M; Nihashi, M; Niida, T; Norman, B E; Nouicer, R; Novitzky, N; Nyanin, A S; Oakley, C; O'Brien, E; Oda, S X; Ogilvie, C A; Ohnishi, H; Oka, M; Okada, K; Omiwade, O O; Onuki, Y; Koop, J D Orjuela; Oskarsson, A; Ouchida, M; Ozaki, H; Ozawa, K; Pak, R; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, I H; Park, J; Park, S; Park, S K; Park, W J; Pate, S F; Patel, L; Patel, M; Pei, H; Peng, J -C; Pereira, H; Perepelitsa, D V; Perera, G D N; Peresedov, V; Peressounko, D Yu; Perry, J; Petti, R; Pinkenburg, C; Pinson, R; Pisani, R P; Proissl, M; Purschke, M L; Purwar, A K; Qu, H; Rak, J; Rakotozafindrabe, A; Ravinovich, I; Read, K F; Rembeczki, S; Reuter, M; Reygers, K; Reynolds, D; Riabov, V; Riabov, Y; Richardson, E; Riveli, N; Roach, D; Roche, G; Rolnick, S D; Romana, A; Rosati, M; Rosen, C A; Rosendahl, S S E; Rosnet, P; Rowan, Z; Rubin, J G; Rukoyatkin, P; Ružička, P; Rykov, V L; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakai, S; Sakashita, K; Sakata, H; Sako, H; Samsonov, V; Sano, S; Sarsour, M; Sato, S; Sato, T; Sawada, S; Schaefer, B; Schmoll, B K; Sedgwick, K; Seele, J; Seidl, R; Semenov, V; Sen, A; Seto, R; Sett, P; Sexton, A; Sharma, D; Shein, I; Shevel, A; Shibata, T -A; Shigaki, K; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, B K; Singh, C P; Singh, V; Skutnik, S; Slunečka, M; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Suire, C; Sukhanov, A; Sumita, T; Sun, J; Sziklai, J; Tabaru, T; Takagi, S; Takagui, E M; Takahara, A; Taketani, A; Tanabe, R; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tarján, P; Themann, H; Thomas, D; Thomas, T L; Timilsina, A; Todoroki, T; Togawa, M; Toia, A; Tojo, J; Tomášek, L; Tomášek, M; Torii, H; Towell, M; Towell, R; Towell, R S; Tram, V-N; Tserruya, I; Tsuchimoto, Y; Vale, C; Valle, H; van Hecke, H W; Vargyas, M; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Vinogradov, A A; Virius, M; Vrba, V; Vznuzdaev, E; Wagner, M; Walker, D; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Wei, R; Wessels, J; Whitaker, S; White, S N; Winter, D; Wolin, S; Woody, C L; Wright, R M; Wysocki, M; Xia, B; Xie, W; Xue, L; Yalcin, S; Yamaguchi, Y L; Yamaura, K; Yang, R; Yanovich, A; Yasin, Z; Ying, J; Yokkaichi, S; Yoon, I; You, Z; Young, G R; Younus, I; Yushmanov, I E; Zajc, W A; Zaudtke, O; Zelenski, A; Zhang, C; Zhou, S; Zimányi, J; Zolin, L

    2014-01-01

    The PHENIX experiment at the Relativistic Heavy Ion Collider has performed a systematic study of $K_S^0$ and $K^{*0}$ meson production at midrapidity in $p$$+$$p$, $d$$+$Au, and Cu$+$Cu collisions at $\\sqrt{s_{_{NN}}}=200$ GeV. The $K_S^0$ and $K^{*0}$ mesons are reconstructed via their $K_S^0 \\rightarrow \\pi^0(\\rightarrow \\gamma\\gamma)\\pi^0(\\rightarrow\\gamma\\gamma)$ and $K^{*0} \\rightarrow K^{\\pm}\\pi^{\\mp}$ decay modes, respectively. The measured transverse-momentum spectra are used to determine the nuclear modification factor of $K_S^0$ and $K^{*0}$ mesons in $d$$+$Au and Cu$+$Cu collisions at different centralities. In the $d$$+$Au collisions, the nuclear modification factor of $K_S^0$ and $K^{*0}$ mesons is almost constant as a function of transverse momentum and is consistent with unity showing that cold-nuclear-matter effects do not play a significant role in the measured kinematic range. In Cu$+$Cu collisions, within the uncertainties no nuclear modification is registered in peripheral collisions. In c...

  9. USGS exploration geochemistry studies at the Pebble porphyry Cu-Au-Mo deposit, Alaska-pdf of presentation

    Science.gov (United States)

    Eppinger, Robert G.; Kelley, Karen D.; Fey, David L.; Giles, Stuart A.; Minsley, Burke J.; Smith, Steven M.

    2010-01-01

    From 2007 through 2010, scientists in the U.S. Geological Survey (USGS) have been conducting exploration-oriented geochemical and geophysical studies in the region surrounding the giant Pebble porphyry Cu-Au-Mo deposit in southwestern Alaska. The Cretaceous Pebble deposit is concealed under tundra, glacial till, and Tertiary cover rocks, and is undisturbed except for numerous exploration drill holes. These USGS studies are part of a nation-wide research project on evaluating and detecting concealed mineral resources. This report focuses on exploration geochemistry and comprises illustrations and associated notes that were presented as a case study in a workshop on this topic. The workshop, organized by L.G. Closs and R. Glanzman, is called 'Geochemistry in Mineral Exploration and Development,' presented by the Society of Economic Geologists at a technical conference entitled 'The Challenge of Finding New Mineral Resources: Global Metallogeny, Integrative Exploration and New Discoveries,' held at Keystone, Colorado, October 2-5, 2010.

  10. Spin and orbital magnetism of coinage metal trimers (Cu3, Ag3, Au3: A relativistic density functional theory study

    Directory of Open Access Journals (Sweden)

    Mahdi Afshar

    2013-11-01

    Full Text Available We have demonstrated electronic structure and magnetic properties of Cu3, Ag3 and Au3 trimers using a full potential local orbital method in the framework of relativistic density functional theory. We have also shown that the non-relativistic generalized gradient approximation for the exchange-correlation energy functional gives reliable magnetic properties in coinage metal trimers compared to experiment. In addition we have indicated that the spin-orbit coupling changes the structure and magnetic properties of gold trimer while the structure and magnetic properties of copper and silver trimers are marginally affected. A significant orbital moment of 0.21μB was found for most stable geometry of the gold trimer whereas orbital magnetism is almost quenched in the copper and silver trimers.

  11. Observation of Andreev bound states in YBa2Cu3O7-d/Au/Nb ramp-type Josephson junctions

    NARCIS (Netherlands)

    Chesca, B.; Doenitz, D.; Dahm, T.; Huebener, R.P.; Koelle, D.; Kleiner, R.; Ariando, A.; Smilde, H.J.H.; Hilgenkamp, Johannes W.M.

    2006-01-01

    We report on Josephson and quasiparticle tunneling in YBa2Cu3O7-x(YBCO)/Au/Nb ramp junctions of several geometries. Macroscopically, tunneling is studied in the ab-plane of YBCO either in the (100) or (010) direction, or in the (110) direction. These junctions have a stable and macroscopically well

  12. Molecular adsorption properties of CO and H2O on Au-, Cu-, and AuxCuy-doped MoS2 monolayer

    Science.gov (United States)

    Kadioglu, Yelda; Gökoğlu, Gökhan; Üzengi Aktürk, Olcay

    2017-12-01

    In this study, we investigate the adsorption properties of Au, Cu, and AuxCuy nanoclusters on MoS2 sheet and the interactions of the adsorbed systems with CO and H2O molecules by using first principles calculations. Results indicate that Au, Cu, or AuxCuy strongly binds to MoS2 monolayer resulting in enhanced chemical activity and sensitivity toward CO and H2O molecules compared to bare MoS2 monolayer. Although both CO and H2O molecules bind weakly to pristine MoS2 monolayer, CO strongly binds to MoS2 sheet in the presence of Au, Cu atoms or AuxCuy clusters. Semiconductor MoS2 monolayer turns into metal upon Au or Cu adsorption. AuxCuy nanocluster adsorption decreases the band gap of MoS2 monolayer acting as a n-type dopant. AuxCuy-doped MoS2 systems have improved adsorption properties for CO and H2O molecules, so the conclusions provided in this study can be useful as a guide for next generation device modeling.

  13. Measurements of directed, elliptic, and triangular flow in Cu$+$Au collisions at $\\sqrt{s_{_{NN}}}=200$ GeV

    CERN Document Server

    Adare, A; Ajitanand, N N; Akiba, Y; Akimoto, R; Alexander, J; Alfred, M; Aoki, K; Apadula, N; Asano, H; Atomssa, E T; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Bai, X; Bandara, N S; Bannier, B; Barish, K N; Bathe, S; Baublis, V; Baumann, C; Baumgart, S; Bazilevsky, A; Beaumier, M; Beckman, S; Belmont, R; Berdnikov, A; Berdnikov, Y; Black, D; Blau, D S; Bok, J S; Boyle, K; Brooks, M L; Bryslawskyj, J; Buesching, H; Bumazhnov, V; Butsyk, S; Campbell, S; Chen, C -H; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choi, S; Christiansen, P; Chujo, T; Cianciolo, V; Citron, Z; Cole, B A; Cronin, N; Crossette, N; Csanád, M; Csörgő, T; Danley, D; Datta, A; Daugherity, M S; David, G; DeBlasio, K; Dehmelt, K; Denisov, A; Deshpande, A; Desmond, E J; Ding, L; Dion, A; Diss, P B; Do, J H; D'Orazio, L; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; Engelmore, T; Enokizono, A; Esumi, S; Eyser, K O; Fadem, B; Feege, N; Fields, D E; Finger, M; Jr., \\,; Fleuret, F; Fokin, S L; Frantz, J E; Franz, A; Frawley, A D; Fukao, Y; Fusayasu, T; Gainey, K; Gal, C; Gallus, P; Garg, P; Garishvili, A; Garishvili, I; Ge, H; Giordano, F; Glenn, A; Gong, X; Gonin, M; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Perdekamp, M Grosse; Gu, Y; Gunji, T; Guragain, H; Hachiya, T; Haggerty, J S; Hahn, K I; Hamagaki, H; Hamilton, H F; Han, S Y; Hanks, J; Hasegawa, S; Haseler, T O S; Hashimoto, K; Hayano, R; He, X; Hemmick, T K; Hester, T; Hill, J C; Hollis, R S; Homma, K; Hong, B; Hoshino, T; Hotvedt, N; Huang, J; Huang, S; Ichihara, T; Ikeda, Y; Imai, K; Imazu, Y; Inaba, M; Iordanova, A; Isenhower, D; Isinhue, A; Ivanishchev, D; Jacak, B V; Jeon, S J; Jezghani, M; Jia, J; Jiang, X; Johnson, B M; Joo, K S; Jouan, D; Jumper, D S; Kamin, J; Kanda, S; Kang, B H; Kang, J H; Kang, J S; Kapustinsky, J; Kawall, D; Kazantsev, A V; Key, J A; Khachatryan, V; Khandai, P K; Khanzadeev, A; Kijima, K M; Kim, C; Kim, D J; Kim, E -J; Kim, G W; Kim, M; Kim, Y -J; Kim, Y K; Kimelman, B; Kistenev, E; Kitamura, R; Klatsky, J; Kleinjan, D; Kline, P; Koblesky, T; Kofarago, M; Komkov, B; Koster, J; Kotchetkov, D; Kotov, D; Krizek, F; Kurita, K; Kurosawa, M; Kwon, Y; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, D M; Lee, G H; Lee, J; Lee, K B; Lee, K S; Lee, S; Lee, S H; Leitch, M J; Leitgab, M; Lewis, B; Li, X; Lim, S H; Liu, M X; Lynch, D; Maguire, C F; Makdisi, Y I; Makek, M; Manion, A; Manko, V I; Mannel, E; Maruyama, T; McCumber, M; McGaughey, P L; McGlinchey, D; McKinney, C; Meles, A; Mendoza, M; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Milov, A; Mishra, D K; Mitchell, J T; Miyasaka, S; Mizuno, S; Mohanty, A K; Mohapatra, S; Montuenga, P; Moon, T; Morrison, D P; Moskowitz, M; Moukhanova, T V; Murakami, T; Murata, J; Mwai, A; Nagae, T; Nagamiya, S; Nagashima, K; Nagle, J L; Nagy, M I; Nakagawa, I; Nakagomi, H; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nattrass, C; Netrakanti, P K; Nihashi, M; Niida, T; Nishimura, S; Nouicer, R; Novak, T; Novitzky, N; Nyanin, A S; O'Brien, E; Ogilvie, C A; Oide, H; Okada, K; Koop, J D Orjuela; Osborn, J D; Oskarsson, A; Ozawa, K; Pak, R; Pantuev, V; Papavassiliou, V; Park, I H; Park, J S; Park, S; Park, S K; Pate, S F; Patel, L; Patel, M; Peng, J -C; Perepelitsa, D V; Perera, G D N; Peressounko, D Yu; Perry, J; Petti, R; Pinkenburg, C; Pinson, R; Pisani, R P; Purschke, M L; Qu, H; Rak, J; Ramson, B J; Ravinovich, I; Read, K F; Reynolds, D; Riabov, V; Riabov, Y; Richardson, E; Rinn, T; Riveli, N; Roach, D; Rolnick, S D; Rosati, M; Rowan, Z; Rubin, J G; Ryu, M S; Sahlmueller, B; Saito, N; Sakaguchi, T; Sako, H; Samsonov, V; Sarsour, M; Sato, S; Sawada, S; Schaefer, B; Schmoll, B K; Sedgwick, K; Seele, J; Seidl, R; Sekiguchi, Y; Sen, A; Seto, R; Sett, P; Sexton, A; Sharma, D; Shaver, A; Shein, I; Shibata, T -A; Shigaki, K; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Singh, B K; Singh, C P; Singh, V; Skolnik, M; Slunečka, M; Snowball, M; Solano, S; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Stankus, P W; Steinberg, P; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Stone, M R; Sugitate, T; Sukhanov, A; Sumita, T; Sun, J; Sziklai, J; Takahara, A; Taketani, A; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tennant, E; Tieulent, R; Timilsina, A; Todoroki, T; Tomášek, M; Torii, H; Towell, C L; Towell, R; Towell, R S; Tserruya, I; van Hecke, H W; Vargyas, M; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Virius, M; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Whitaker, S; White, A S; Wolin, S; Woody, C L; Wysocki, M; Xia, B; Xue, L; Yalcin, S; Yamaguchi, Y L; Yanovich, A; Yokkaichi, S; Yoo, J H; Yoon, I; You, Z; Younus, I; Yu, H; Yushmanov, I E; Zajc, W A; Zelenski, A; Zhou, S; Zou, L

    2015-01-01

    Measurements of anisotropic flow Fourier coefficients ($v_n$) for inclusive charged particles and identified hadrons $\\pi^{\\pm}$, $K^{\\pm}$, $p$, and $\\bar{p}$ produced at midrapidity in Cu+Au collisions at $\\sqrt{s_{_{NN}}}=200$ GeV are presented. The data were collected in 2012 by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC). The particle azimuthal distributions with respect to different order symmetry planes $\\Psi_n$, for $n$~=~1, 2, and 3 are studied as a function of transverse momentum $p_T$ over a broad range of collisions centralities. Mass ordering, as expected from hydrodynamic flow, is observed for all three harmonics. The charged-particle results are compared to hydrodynamical and transport model calculations. We also compare these Cu$+$Au results with those in Cu$+$Cu and Au$+$Au collisions at the same $\\sqrt{s_{_{NN}}}$, and find that the $v_2$ and $v_3$, as a function of transverse momentum, follow a common scaling with $1/(\\varepsilon_n N_{\\rm part}^{1/3})$.

  14. Y-Ba-Cu-O/Au/Nb ramp-type Josephson junctions

    NARCIS (Netherlands)

    Smilde, H.J.H.; Hilgenkamp, Johannes W.M.; Gerritsma, G.J.; Blank, David H.A.; Rogalla, Horst

    2001-01-01

    Ramp-type junctions connecting the d-wave superconductor YBazCu307.s and the s-wave superconductor niobium are fabricated using a thin gold layer as a chemical barrier. High critical current densities exceeding 5 kA/cm2 are obtained. The normal state resistivity (R,& values of the junctions are of

  15. A new strategy to construct a C=C-CF3 subunit via CuBr-catalyzed domino reaction of homopropargyl amines: an efficient synthesis of trifluoromethyl containing building blocks 4-trifluoromethyl-2,3-dihydro-pyrroliums.

    Science.gov (United States)

    Ge, Guang-Cun; Huang, Xiao-Jun; Ding, Chang-Hua; Wan, Shi-Li; Dai, Li-Xin; Hou, Xue-Long

    2014-03-21

    A new strategy for the construction of a C=C-CF3 subunit has been developed via CuBr-catalyzed domino cyclization-trifluoromethylation of homopropargyl amines with Umemoto's reagent. 4-Trifluoromethyl-2,3-dihydro-pyrroliums were produced in high yields. The usefulness of these products has been demonstrated by the transformation of them into various other trifluoromethylated molecules.

  16. On the Structural Features of Mechanically Alloyed Cu-Ag and Au-Co by Severe Cold and Cryogenic Plastic Deformation

    Science.gov (United States)

    Tolmachev, T.; Pilyugin, V.; Ancharov, A.; Patselov, A.; Chernyshev, E.; Zolotarev, K.

    The effect of cryogenic temperature on the formation of solid solutions by mechanical alloying (MA) was studied using synchrotron diffraction and some additional methods. Two systems with different positive enthalpy of mixing (Cu-Ag i Au-Co) were involved. MA by severe plastic deformation at 293 K and 80 K leads to the formation of fcc substitutional solid solutions, with the excess of the equilibrium concentration for both systems. The effect of cryogenic deformation consists in smaller dissolution of the original basic element of the charge (Cu) for Cu-Ag solid solution and in increasing of solute (Co) for Au-Co one. Diffraction experiments were performed at the SR beamline №4 of the VEPP-3 storage ring.

  17. Ammonia synthesis on Au modified Fe(111) and Ag and Cu modified Fe(100) surfaces

    DEFF Research Database (Denmark)

    Lytken, Ole; Waltenburg, Hanne Neergaard; Chorkendorff, Ib

    2003-01-01

    and a high-pressure cell. Ammonia was synthesized from a stoichiometric (N-2:3H(2)) gas mixture at a pressure of 2 bar. By deposition of small amounts of An, the ammonia production activity of the Fe(1 1 1) surface can be enhanced. More important, for the gold modified surface, the reaction order in ammonia...... to lifting of the nitrogen induced reconstruction of the Fe(I 11). On the Fe(l 00) surface strong effects were expected from modification with Cu and Ag since the in general more reactive atomic steps always present on such surfaces would be blocked. However, only minor and modest negative effects were found....... The Cu and Ag were found to be inefficient step blockers as they were forced away from the surface by the formation of the much more stable surface nitrogen....

  18. Aide aux femmes ayant survécu à des actes de violence au cours ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les données sur la violence sexuelle à l'égard des femmes et des hommes, tant pendant qu'après les conflits, ont un caractère alarmant dans toutes les régions du monde. D'après ONU Femmes, au moins 200 000 cas de violence sexuelle, la plupart à l'endroit des femmes et des jeunes filles, ont été constatés dans l'est ...

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

    Energy Technology Data Exchange (ETDEWEB)

    Yi Hua Ma; Natalie Pomerantz; Chao-Huang Chen

    2008-09-30

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

  20. Magmatic and structural controls on porphyry-style Cu-Au-Mo mineralization at Kemess South, Toodoggone District of British Columbia, Canada

    Science.gov (United States)

    Duuring, Paul; Rowins, Stephen M.; McKinley, Bradley S. M.; Dickinson, Jenni M.; Diakow, Larry J.; Kim, Young-Seog; Creaser, Robert A.

    2009-05-01

    Kemess South is the only Cu-Au-Mo mine in the Toodoggone district and a major Cu and Au producer in British Columbia. Porphyry-style Cu-Au-Mo mineralization is mainly hosted by the tabular, SW-plunging, 199.6 ± 0.6-Ma Maple Leaf granodiorite, which intrudes tightly folded, SW-dipping, Permian Asitka Group siltstone and limestone and homogeneous Triassic Takla Group basalt. Southwest-dipping 194.0 ± 0.4-Ma Toodoggone Formation conglomerate, volcaniclastic, and epiclastic rocks overlie the granodiorite and Asitka Group rocks. Minor Cu-Au-Mo mineralization is hosted by the immediate Takla Group basalt country rock, whereas low-tonnage high-grade Cu zones occur beneath a 30-m-thick leached capping in supergene-altered granodiorite and in exotic positions in overlying Toodoggone Formation conglomerate. Granodiorite has an intrusive contact with mineralized and altered Takla Group basalt but displays a sheared contact with unmineralized and less altered Asitka Group siltstone. The North Block fault is a deposit-scale, E-striking, steeply S-dipping normal fault that juxtaposes the granodiorite/basalt ore body against unmineralized Asitka Group rocks. Younger NW- and NE-striking normal-dextral faults cut all rock types, orebodies, and the North Block fault with displacements of up to 100 m and result in the graben-and-horst-style block faulting of the stratigraphy and ore body. Both basalt and granodiorite host comparable vein sequence and alteration histories, with minor variations in hydrothermal mineral assemblages caused by differing protolith chemistry. Early potassic alteration (and associated early-stage Cu ± Au ± Mo mineralization) is partly replaced by phyllic and intermediate argillic alteration associated with main-stage Cu-Au-Mo mineralization. Two main-stage veins have Re-Os molybdenite ages of 201.3 ± 1.2 and 201.1 ± 1.2 Ma. These mineralization ages overlap the 199.6 ± 0.6-Ma U-Pb zircon crystallization age for the Maple Leaf granodiorite. Late

  1. Platinum-group element geochemistry used to determine Cu and Au fertility in the Northparkes igneous suites, New South Wales, Australia

    Science.gov (United States)

    Hao, Hongda; Campbell, Ian H.; Park, Jung-Woo; Cooke, David R.

    2017-11-01

    Recent studies have shown that platinum-group elements (PGE) can be used to constrain the timing of sulfide saturation in evolving felsic systems. In this study, we report trace-element, PGE, Re and Au data for the barren and ore-associated suites of intermediate to felsic rocks from the Northparkes Cu-Au porphyry region, emphasizing the timing of sulfide saturation and its influence on the tenor of the associated hydrothermal mineralization. Two barren suites, the Goonumbla and Wombin Volcanics and associate intrusive rocks, are found in the region. Geochemical modelling shows that the barren suites are dominated by plagioclase-pyroxene fractionation, whereas the ore-associated Northparkes Cu-Au porphyry suite is characterized by plagioclase-amphibole fractionation, which requires the ore-bearing suite to have crystallized from a wetter magma than barren suites. The concentrations of PGE, Re and Au in the barren suites decrease continuously during fractional crystallization. This is attributed to early sulfide saturation with the fraction of immiscible sulfide precipitation required to produce the observed trend, being 0.13 and 0.16 wt.% for the Goonumbla and Wombin suites, respectively. The calculated partition coefficients for Au and Pd required to model the observed change in these elements with MgO are well below published values, indicating that R, the mass ratio of silicate to sulfide melt, played a significant role in controlling the rate of decline of these elements with fractionation. Palladium in the ore-associated suite, in contrast, first increases with fractionation then decreases abruptly at 1.2 wt.% MgO. The sharp decrease is attributed to the onset of sulfide precipitation. Platinum on the other hand shows a moderate decrease, starting from the highest MgO sample analysed, but then decreasing strongly from 1.2 wt.% MgO. The initial Pt decrease is attributed to precipitation of a platinum-group mineral (PGM), probably a Pt-Fe alloy, and the sharp

  2. A Au/Cu2O-TiO2 system for photo-catalytic hydrogen production. A pn-junction effect or a simple case of in situ reduction?

    KAUST Repository

    Sinatra, Lutfan

    2015-02-01

    Photo-catalytic H2 production from water has been studied over Au-Cu2O nanoparticle deposited on TiO2 (anatase) in order to probe into both the plasmon resonance effect (Au nanoparticles) and the pn-junction at the Cu2O-TiO2 interface. The Au-Cu2O composite is in the form of ∼10 nm Au nanoparticles grown on ∼475 nm Cu2O octahedral nanocrystals with (111) facets by partial galvanic replacement. X-ray Photoelectron Spectroscopy (XPS) Cu2p and Auger L3M4,5M4,5 lines indicate that the surface of Cu2O is mainly composed of Cu+. The rate for H2 production (from 95 water/5 ethylene glycol; vol.%) over 2 wt.% (Au/Cu2O)-TiO2 is found to be ∼10 times faster than that on 2 wt.% Au-TiO2 alone. Raman spectroscopy before and after reaction showed the disappearance of Cu+ lines (2Eu) at 220 cm-1. These observations coupled with the induction time observed for the reaction rate suggest that in situ reduction from Cu+ to Cu0 occurs upon photo-excitation. The reduction requires the presence of TiO2 (electron transfer). The prolonged activity of the reaction (with no signs of deactivation) despite the reduction to Cu0 indicates that the latter takes part in the reaction by providing additional sites for the reaction, most likely as recombination centers for hydrogen atoms to form molecular hydrogen. This phenomenon provides an additional route for enhancing the efficiency and lifetime of Cu2O-TiO2 photocatalytic systems, beyond the usually ascribed pn-junction effect.

  3. Geology, mineralization, and fluid inclusion characteristics of the Kumbel oxidized W-Cu-Mo skarn and Au-W stockwork deposit in Kyrgyzstan, Tien Shan

    Science.gov (United States)

    Soloviev, Serguei G.

    2015-02-01

    The Kumbel deposit is located within a metallogenic belt of W-Mo, Cu-Mo, Au-W, and Au deposits along the Late Paleozoic active continental margin of Tien Shan. The deposit is related to a Late Carboniferous multiphase pluton, with successive intrusive phases from early olivine monzogabbro through monzonite-quartz monzonite to granodiorite and granite, with the latest monzogabbro-porphyry dikes. The deposit represents an example of a complex W-Cu-Mo-Au magmatic-hydrothermal system related to magnetite-series high-K calc-alkaline to shoshonitic igneous suite. It contains large bodies of W-Cu-Mo oxidized prograde and retrograde skarns, with abundant andradite garnet, magnetite, and especially hematite, as well as K-feldspar, molybdoscheelite, chalcopyrite, and molybdenite, with transitions to zones of intense quartz-K-feldspar (with minor andradite and hematite) veining. The skarns are cut by quartz-carbonate ± adularia ± sericite veins (locally sheeted) and stockworks bearing scheelite and minor Cu, Zn, Pb sulfides, as well as Au, Bi, Te, and As mineralization. The association of these veins with the oxidized skarns and magnetite-series intrusion is consistent with the general oxidized, intrusion-related W-Mo-Cu-Au type of deposit, with an affinity to the alkalic (silica-saturated) Cu-Au ± Mo porphyry deposits. The fluid inclusion data show the predominance of magmatic-hydrothermal aqueous chloride fluid during the formation of skarns and quartz-carbonate-scheelite-sulfide veins. The high fluid pressures (˜1,750 bars), together with their high temperature (up to 600 °C) and high salinity (˜50-60 wt% NaCl-equiv.), suggest the formation of skarns and quartz-K-feldspar-andradite-hematite veins under conditions typical of magmatic-hydrothermal transition (depth of ≥4-5 km) of intrusion-related mineralized system, possibly by exsolution of the fluids from crystallizing magma. The auriferous quartz-carbonate-scheelite-sulfide veins formed from high to moderate

  4. Ab initio molecular dynamics calculations on scattering of hyperthermal H atoms from Cu(111) and Au(111).

    Science.gov (United States)

    Kroes, Geert-Jan; Pavanello, Michele; Blanco-Rey, María; Alducin, Maite; Auerbach, Daniel J

    2014-08-07

    Energy loss from the translational motion of an atom or molecule impinging on a metal surface to the surface may determine whether the incident particle can trap on the surface, and whether it has enough energy left to react with another molecule present at the surface. Although this is relevant to heterogeneous catalysis, the relative extent to which energy loss of hot atoms takes place to phonons or electron-hole pair (ehp) excitation, and its dependence on the system's parameters, remain largely unknown. We address these questions for two systems that present an extreme case of the mass ratio of the incident atom to the surface atom, i.e., H + Cu(111) and H + Au(111), by presenting adiabatic ab initio molecular dynamics (AIMD) predictions of the energy loss and angular distributions for an incidence energy of 5 eV. The results are compared to the results of AIMDEFp calculations modeling energy loss to ehp excitation using an electronic friction ("EF") model applied to the AIMD trajectories, so that the energy loss to the electrons is calculated "post" ("p") the computation of the AIMD trajectory. The AIMD calculations predict average energy losses of 0.38 eV for Cu(111) and 0.13-0.14 eV for Au(111) for H-atoms that scatter from these surfaces without penetrating the surface. These energies closely correspond with energy losses predicted with Baule models, which is suggestive of structure scattering. The predicted adiabatic integral energy loss spectra (integrated over all final scattering angles) all display a lowest energy peak at an energy corresponding to approximately 80% of the average adiabatic energy loss for non-penetrative scattering. In the adiabatic limit, this suggests a way of determining the approximate average energy loss of non-penetratively scattered H-atoms from the integral energy loss spectrum of all scattered H-atoms. The AIMDEFp calculations predict that in each case the lowest energy loss peak should show additional energy loss in the

  5. First-principles investigation of local structure deformation induced by x-ray irradiation in κ -(BEDT-TTF ) 2Cu [N (CN) 2 ] Br

    Science.gov (United States)

    Kang, Lijing; Akagi, Kazuto; Hayashi, Kouichi; Sasaki, Takahiko

    2017-06-01

    We investigated the local structure deformation induced by x-ray irradiation in an organic molecular conductor κ -(BEDT-TTF ) 2Cu [N (CN) 2 ] Br using density-functional-theory (DFT-) based first-principles calculations. Our results demonstrate that the structure change due to x-ray excitation can be predicted by introducing a core hole at specific light atoms of the anion molecules with an infinite lifetime. The formation of a bond-shifted structure triggered by a double excitation was expected as a possible irreversible molecular defect leading to permanent irradiation damage. The calculated change in molecular vibration spectra after irradiation was consistent with the experimental results, and some different vibration modes by further irradiation were also predicted. The calculated local density of states indicates that the bond-shifted structure in the anion layer causes local potential modulation to the carriers (holes) in the cation layer. The introduced potential disorder for the carriers could increase the resistivity due to a localization effect that has been observed experimentally so far.

  6. Frustration and Dzyaloshinsky-Moriya anisotropy in the kagome francisites Cu3Bi (SeO3)2 O2X (X = Br , Cl )

    Science.gov (United States)

    Rousochatzakis, Ioannis; Richter, Johannes; Zinke, Ronald; Tsirlin, Alexander A.

    2015-01-01

    We investigate the antiferromagnetic canting instability of the spin-1/2 kagome ferromagnet, as realized in the layered cuprates Cu3Bi (SeO3)2 O2X (X = Br , Cl ). While the local canting can be explained in terms of competing exchange interactions, the direction of the ferrimagnetic order parameter fluctuates strongly even at short distances on account of frustration which gives rise to an infinite ground state degeneracy at the classical level. In analogy with the kagome antiferromagnet, the accidental degeneracy is fully lifted only by nonlinear 1 /S corrections, rendering the selected uniform canted phase very fragile even for spins-1/2, as shown explicitly by coupled-cluster calculations. To account for the observed ordering, we show that the minimal description of these systems must include the microscopic Dzyaloshinsky-Moriya interactions, which we obtain from density-functional band-structure calculations. The model explains all qualitative properties of the kagome francisites, including the detailed nature of the ground state and the anisotropic response under a magnetic field. The predicted magnon excitation spectrum and quantitative features of the magnetization process call for further experimental investigations of these compounds.

  7. Geochronology and crustal evolution of the deposit area Cu-Au Gameleira, Carajas mineral province, Para state, Brazil; Geocronologia e evolucao crustal da area do deposito de Cu-Au Gameleira, provincia mineral de Carajas (Para), Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Galarza, Marco Antonio; Macambira, Moacir Jose Buenano [Para Univ. (UFPA), Belem (Brazil). Centro de Geociencias. Lab. de Geologia Isotopica (Para-Iso)

    2002-12-15

    The Gameleira Cu-Au deposit is hosted by rocks of the Igarape Pojuca Group, Itacaiunas Supergroup, Carajas Mineral Province, southeastern Amazonian Craton. This group is represented mainly by mafic metavolcanic rocks (MVN), amphibolite, biotite schist, banded iron formation and/or hydrothermalite and cut by intrusive mafic rocks (IMR) as well as by deformed Itacaiunas granites of Archean age (2.56 Ga) and Pojuca and Gameleira granites of Proterozoic age (1.87 and 1.58 Ga). Zircon crystals from a saprolite (2615 {+-} 10 Ma and 2683 {+-} 7 Ma) and from an IMR sample (2705 {+-} 2 Ma) are coeval with those from gabbros of the neighboring Aguas Claras deposit. Pb-Pb dating of whole rock samples and chalcopyrite from the MVR indicated ages of 2245 {+-} 29 Ma and 2419 {+-} 12 Ma, respectively, while leached chalcopyrite yielded ages of 2217 {+-} 19 Ma and 2180 {+-} 84 Ma. These ages are interpreted as due to partial resetting provoked by the Proterozoic granitic intrusions or by tectonic reactivation along the Carajas and Cinzento strike slip systems or alternatively, as due to total resetting provoked by the last one. The T{sub DM} ages between 3.12 and 3.33 Ga for the MVR and IMR, and the initial epsilon{sub Nd} (t) values of -0.89 to -3.26 suggest continental contribution from older crustal material and possibly magma generation in a continental rift or active continental margin environment. (author)

  8. Mass and charge flow in the reaction 7.1 MeV/u197Au+63Cu

    Science.gov (United States)

    Jäckel, B.; Rox, A.; Esterlund, R. A.; Westmeier, W.; Knaack, M.; Patzelt, P.

    1991-12-01

    Mass-yield and angular-distribution data are presented for products from the reaction of 7.1 MeV/ μ 197Au with63Cu. With help from information derived from the latter, the former are classified into components corresponding to quasielastic transfer (580±80 mb), deep-inelastic transfer plus quasifission (1300±130 mb), fusionfission (≦195 mb), and sequential fission (195±45 mb). The fusion excitation function calculated with the Dynamic Capture model standard parameter set reproduces our deduced fusion-fission cross section well. Moreover, using this cross section as well as additional published data for the same reaction system, we extract an s-wave fusion-barrier shift (“extra push”) for this system of 35±7 MeV, which is in good agreement with the systematics derived from other fusion-barrier shifts which have been reported in the literature. Lastly, support is found for the Dissipative Diabatic Dynamics model prediction that dynamically-hindered fusion trajectories are reflected into quasielastic channels.

  9. Mass and charge flow in the reaction 7. 1 MeV/u sup 197 Au+ sup 63 Cu

    Energy Technology Data Exchange (ETDEWEB)

    Jaeckel, B.; Rox, A.; Esterlund, R.A.; Westmeier, W.; Knaack, M.; Patzelt, P. (Marburg Univ. (Germany, F.R.). Fachgebiet Kernchemie)

    1991-08-01

    Mass-yield and angular-distribution data are presented for products from the reaction of 7.1 MeV/u {sup 197}Au with {sup 63}Cu. With help from information derived from the latter, the former are calssified into components corresponding to quasielastic transfer (580+-80 mb), deep-inelastic transfer plus quasifission (1300+-130 mb), fusion-fission ({le}195 mb), and sequential fission (195+-45 mb). The fusion excitation function calculated with the Dynamic Capture model standard parameter set reproduces our deduced fusion-fission cross section well. Moreover, using this cross section as well as additional published data for the same reaction system, we extract an s-wave fusion-barrier shift ('extra push') for this system of 35+-7 MeV, which is in good agreement with the systematics derived from other fusion-barrier shifts which have been reported in the literature. Lastly, support is found for the Dissipative Diabatic Dynamics model prediction that dynamically-hindered fusion trajectories are reflected into quasielastic channels. (orig.).

  10. Geology, mineralization, and fluid inclusion study of the Kuru-Tegerek Au-Cu-Mo skarn deposit in the Middle Tien Shan, Kyrgyzstan

    Science.gov (United States)

    Soloviev, Serguei G.; Kryazhev, Sergey; Dvurechenskaya, Svetlana

    2017-04-01

    The Kuru-Tegerek Cu-Au-Mo deposit is situated in a system of Late Carboniferous subduction-related magmatic arcs of the Middle Tien Shan, which together constitute a metallogenic belt of Cu-Au-Mo (±W) porphyry, with local skarns, deposits. The deposit is related to magnetite-series gabbro-diorite to tonalite intrusion. It contains prograde magnesian and calcic skarns with abundant magnetite, associated with gabbro-diorite, and retrograde skarn with Cu mineralization, formed after intrusion of tonalite. Subsequent propylitic alteration introduced abundant chalcopyrite and pyrrhotite, and native Au culminating in zones overprinting magnetite and garnet skarn. Later quartz-muscovite-carbonate veins, formed after intrusion of late mafic quartz monzogabbro dikes, contain chalcopyrite, pyrite, arsenopyrite and other sulfides and sulfosalts, tellurides, and native Au. The earliest retrograde skarn garnet contains gaseous low-salinity (1.7-3.4 wt.% NaCl eq.) fluid inclusions homogenizing at 460-500 °C into vapor, indicating that the early fluid released from crystallizing magma was a low-density vapor. It was followed by more saline (4.0-5.0 wt.% NaCl eq.), high-temperature (400-440 °C) aqueous fluid, as fluid release from the magma progressed. Boiling of this fluid at temperatures of 420 to 370 °C and a pressure of 350-300 bar produced a low-salinity (0.6-1.2 wt.% NaCl eq.), essentially gaseous, and high-salinity (from 39 to 31 wt.% NaCl eq.) brine, with possible metal (including Cu) partitioning into both gaseous and aqueous-saline phases. Boiling was coeval with sulfide deposition in the retrograde skarn. The latest episode of the retrograde skarn stage included direct separation of saline ( 40-42 wt.% NaCl eq.) fluid from crystallizing magma. The separation of saline ( 40 to 14 wt.% NaCl eq.) fluids from a crystallizing magmatic melt continued during the propylitic stage, when fluid cooling from 370 to 320 °C, together with decreasing fO2, caused Cu and especially

  11. Geology, mineralization, and fluid inclusion study of the Kuru-Tegerek Au-Cu-Mo skarn deposit in the Middle Tien Shan, Kyrgyzstan

    Science.gov (United States)

    Soloviev, Serguei G.; Kryazhev, Sergey; Dvurechenskaya, Svetlana

    2018-02-01

    The Kuru-Tegerek Cu-Au-Mo deposit is situated in a system of Late Carboniferous subduction-related magmatic arcs of the Middle Tien Shan, which together constitute a metallogenic belt of Cu-Au-Mo (±W) porphyry, with local skarns, deposits. The deposit is related to magnetite-series gabbro-diorite to tonalite intrusion. It contains prograde magnesian and calcic skarns with abundant magnetite, associated with gabbro-diorite, and retrograde skarn with Cu mineralization, formed after intrusion of tonalite. Subsequent propylitic alteration introduced abundant chalcopyrite and pyrrhotite, and native Au culminating in zones overprinting magnetite and garnet skarn. Later quartz-muscovite-carbonate veins, formed after intrusion of late mafic quartz monzogabbro dikes, contain chalcopyrite, pyrite, arsenopyrite and other sulfides and sulfosalts, tellurides, and native Au. The earliest retrograde skarn garnet contains gaseous low-salinity (1.7-3.4 wt.% NaCl eq.) fluid inclusions homogenizing at 460-500 °C into vapor, indicating that the early fluid released from crystallizing magma was a low-density vapor. It was followed by more saline (4.0-5.0 wt.% NaCl eq.), high-temperature (400-440 °C) aqueous fluid, as fluid release from the magma progressed. Boiling of this fluid at temperatures of 420 to 370 °C and a pressure of 350-300 bar produced a low-salinity (0.6-1.2 wt.% NaCl eq.), essentially gaseous, and high-salinity (from 39 to 31 wt.% NaCl eq.) brine, with possible metal (including Cu) partitioning into both gaseous and aqueous-saline phases. Boiling was coeval with sulfide deposition in the retrograde skarn. The latest episode of the retrograde skarn stage included direct separation of saline ( 40-42 wt.% NaCl eq.) fluid from crystallizing magma. The separation of saline ( 40 to 14 wt.% NaCl eq.) fluids from a crystallizing magmatic melt continued during the propylitic stage, when fluid cooling from 370 to 320 °C, together with decreasing fO2, caused Cu and especially

  12. A label-free electrochemical immunosensor based on the novel signal amplification system of AuPdCu ternary nanoparticles functionalized polymer nanospheres.

    Science.gov (United States)

    Yan, Qin; Yang, Yuying; Tan, Zhaoling; Liu, Qing; Liu, Hui; Wang, Ping; Chen, Lei; Zhang, Daopeng; Li, Yueyun; Dong, Yunhui

    2018-04-30

    A sensitive label-free electrochemical immunosensor was designed using a novel signal amplification system for quantitative detecting hepatitis B surface antigen (HBsAg). Nitrogen-doped graphene quantum dots (N-GQDs) supported surfactant-free AuPdCu ternary nanoparticles (AuPdCu/N-GQDs), which featured with good conductivity and excellent catalytic properties for the reduction of hydrogen peroxide (H 2 O 2 ), was synthesized by a simple and benign hydrothermal procedure. At the same time, the electroactive polymer nanospheres (PS) was synthesized by infinite coordination polymers of ferrocenedicarboxylic acid, which could play as carrier and electronic mediator to load AuPdCu/N-GQDs. The PS not only improved the ability to load antibodies because of the good biocompatibility, but also accelerated electron transport of the electrode interface attribute to plentiful ferrocene unit. Thus, the prepared AuPdCu/N-GQDs@PS has abilities of good biocompatibility, catalytic activity and electrical conductivity to be applied as transducing materials to amplify electrochemical signal in detection of HBsAg. Under optimal conditions, the fabricated immunosensor exhibited high sensitivity and stability in the detection of HBsAg. A linear relationship between current signals and the concentrations of HBsAg was obtained in the range from 10fg/mL to 50ng/mL and the detection limit of HBsAg was 3.3fg/mL (signal-to-noise ratio of 3). Moreover, the designed immunosensor with excellent selectivity, reproducibility and stability shows excellent performance in detection of human serum samples. Furthermore, this label-free electrochemical immunosensor has promising application in clinical diagnosis of HBsAg. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Data integration modeling applied to drill hole planning through semi-supervised learning: A case study from the Dalli Cu-Au porphyry deposit in the central Iran

    Science.gov (United States)

    Fatehi, Moslem; Asadi, Hooshang H.

    2017-04-01

    In this study, the application of a transductive support vector machine (TSVM), an innovative semi-supervised learning algorithm, has been proposed for mapping the potential drill targets at a detailed exploration stage. The semi-supervised learning method is a hybrid of supervised and unsupervised learning approach that simultaneously uses both training and non-training data to design a classifier. By using the TSVM algorithm, exploration layers at the Dalli porphyry Cu-Au deposit in the central Iran were integrated to locate the boundary of the Cu-Au mineralization for further drilling. By applying this algorithm on the non-training (unlabeled) and limited training (labeled) Dalli exploration data, the study area was classified in two domains of Cu-Au ore and waste. Then, the results were validated by the earlier block models created, using the available borehole and trench data. In addition to TSVM, the support vector machine (SVM) algorithm was also implemented on the study area for comparison. Thirty percent of the labeled exploration data was used to evaluate the performance of these two algorithms. The results revealed 87 percent correct recognition accuracy for the TSVM algorithm and 82 percent for the SVM algorithm. The deepest inclined borehole, recently drilled in the western part of the Dalli deposit, indicated that the boundary of Cu-Au mineralization, as identified by the TSVM algorithm, was only 15 m off from the actual boundary intersected by this borehole. According to the results of the TSVM algorithm, six new boreholes were suggested for further drilling at the Dalli deposit. This study showed that the TSVM algorithm could be a useful tool for enhancing the mineralization zones and consequently, ensuring a more accurate drill hole planning.

  14. The antimony-group 11 chemical bond: dissociation energies of the diatomic molecules CuSb, AgSb, and AuSb.

    Science.gov (United States)

    Carta, V; Ciccioli, A; Gigli, G

    2014-02-14

    The intermetallic molecules CuSb, AgSb, and AuSb were identified in the effusive molecular beam produced at high temperature under equilibrium conditions in a double-cell-like Knudsen source. Several gaseous equilibria involving these species were studied by mass spectrometry as a function of temperature in the overall range 1349-1822 K, and the strength of the chemical bond formed between antimony and the group 11 metals was for the first time measured deriving the following thermochemical dissociation energies (D°(0), kJ/mol): 186.7 ± 5.1 (CuSb), 156.3 ± 4.9 (AgSb), 241.3 ± 5.8 (AuSb). The three species were also investigated computationally at the coupled cluster level with single, double, and noniterative quasiperturbative triple excitations (CCSD(T)). The spectroscopic parameters were calculated from the potential energy curves and the dissociation energies were evaluated at the Complete Basis Set limit, resulting in an overall good agreement with experimental values. An approximate evaluation of the spin-orbit effect was also performed. CCSD(T) calculations were further extended to the corresponding group 11 arsenide species which are here studied for the first time and the following dissociation energies (D°(0), kJ/mol): 190 ± 10 (CuAs), 151 ± 10 (AgAs), 240 ± 15 (AuAs) are proposed. Taking advantage of the new experimental and computational information here presented, the bond energy trends along group 11 and 4th and 5th periods of the periodic table were analyzed and the bond energies of the diatomic species CuBi and AuBi, yet experimentally unobserved, were predicted on an empirical basis.

  15. Synthesis and characterization of the 1.1 adducts of copper(1) halides with bidentatate N,N-bis(benzophenone)-1,2-diiminoethane Schiff bases: Crystal structures of [Cu(bz2en)2][CuX2](X=Br,l) complexes

    NARCIS (Netherlands)

    Kia, Reza; Mirkhani, Valiollah; Harkema, Sybolt; van Hummel, G.J.

    2007-01-01

    1:1 adducts of N,N′-bis(benzophenone)-1,2-diiminoethane (bz2en) with copper(I) chloride, bromide and iodide, [Cu(bz2en)2][CuX2] (X = Cl, Br, and I), have been synthesized and the structures of the solid bromide and iodide adducts were determined by X-ray crystallography from single-crystal data. The

  16. Comparative Study on The Photocatalytic Hydrogen Production from Methanol over Cu-, Pd-, Co- and Au-Loaded TiO2

    Directory of Open Access Journals (Sweden)

    Udani P.P.C.

    2015-09-01

    Full Text Available Photocatalytic hydrogen production from a methanol-water solution was investigated in a semi-continuous reactor over different metal-loaded TiO2 catalysts under UltraViolet (UV light irradiation. The catalysts were mainly prepared by the incipient wetness impregnation method by varying the metal weight ratio in the range of 1-10 wt%. The effects of metal loading and H2 pre-treatment on the photocatalytic activity were investigated. In addition, the activity of the catalysts was also compared with a reference Au-TiO2 catalyst from the World Gold Council (WGC. The photocatalysts were characterized by using X-Ray Diffraction (XRD and N2 physisorption before and after the activity measurements. The photocatalytic activity decreased in the order of Pd > Au > Cu > Co in the comparative study of Cu-TiO2, Co-TiO2, Au-TiO2 and Pd-TiO2. Optimum hydrogen evolution was achieved with 5 wt% Pd-TiO2 and 5 wt% Cu-TiO2.

  17. LDA-Prediction of New Stable Crystal Structures within=0A= the Cu-Au and Ni-Pt Alloy Systems.^*

    Science.gov (United States)

    Sanati, M.; Wang, L.; Zunger, Alex

    2002-03-01

    Cu-Au and Ni-Pt are among the best studied fcc alloy systems, exhibiting the famous L10 (AB) and L12 (A_3B) phases. We were wondering if a complete configurational search of the T=3D0 LDA total energies would reveal any unexpected phases. Total-energy calculations of ~ 30 arbitrarily chosen structures were used to construct a generalized (momentum-space) Ising Hamiltonian containing ~ 20 pair-interactions, ~ 5-10 many-body terms, as well as the long-range strain term. This Hamiltonian was tested carefully as to its ability to predict the LDA energies of other structures. Once accuracy is established, we searched the energies of all fcc configurations with 20 or less atoms per primitive cell ( ~ 2,700,000 structures), finding the known L1_0, L12 plus new, unsuspected structures. The new ground state structures are NiPt_7, Cu_2Au, and Cu_2Au_3. We find that LDA calculations of these structures confirm that they are ground states. We describe the band structure and other properties of these new structures. ^* Supported by DOE, SC-BES-DMS. abstract.

  18. Etude de la succession secondaire dans le cadre de la pratique des cultures sur brûlis au Menabe central, Madagascar

    OpenAIRE

    Raharimalala, Hanitriaina Olga Jeannine; Gobat, Jean-Michel

    2011-01-01

    Madagascar est connu pour ses richesses en biodiversité et ses écosystèmes uniques. Une forte pression d'origine anthropique entraîne pourtant une destruction rapide des habitats naturels et une perte massive de cette biodiversité. La culture sur brûlis est une des causes de cette pression. Il s’agit d’une pratique traditionnelle et prédominante dans plusieurs régions à Madagascar et notamment dans le Sud-Ouest. La végétation secondaire qui s’installe sur les parcelles anciennement brûlées pu...

  19. Les facteurs territoriaux de la compétitivité de la filière soja au Brésil

    Directory of Open Access Journals (Sweden)

    Bertrand Jean-Pierre

    2001-05-01

    Full Text Available Ce papier discute les facteurs de progression du complexe soja dans les régions de Cerrados du Nord du Brésil, proches de la forêt amazonienne. Le Mato Grosso est déjà le premier État producteur de soja du Brésil, tandis que le Para entre dans le processus de production intensif. Les deux États obtiennent des rendements élevés ; mais ils risquent de connaître des problèmes environnementaux du fait d’un usage excessif des pesticides.

  20. Le Brésil au cœur des stratégies spatiales du recrutement des clubs européens de football

    Directory of Open Access Journals (Sweden)

    Bertrand Piraudeau

    2009-10-01

    Full Text Available Depuis la fin des années 1990, le nombre de footballeurs brésiliens évoluant dans les clubs professionnels internationaux augmente constamment. Les principaux championnats européens (Allemagne, Angleterre, Espagne, France, Italie et Portugal sont très courtisés par les joueurs brésiliens. L'histoire des relations entre les territoires et les stratégies spatiales du recrutement développées par les clubs de football européens font apparaître un système productif de joueurs brésiliens et des canaux migratoires très organisés entre l'Europe et le Brésil.Depuis la fin des années 1990, le nombre de footballeurs brésiliens évoluant dans les clubs professionnels internationaux augmente constamment. Les principaux championnats européens (Allemagne, Angleterre, Espagne, France, Italie et Portugal sont très courtisés par les joueurs brésiliens. L'histoire des relations entre les territoires et les stratégies spatiales du recrutement développées par les clubs de football européens font apparaître un système productif de joueurs brésiliens et des canaux migratoires très organisés entre l'Europe et le Brésil.Desde o fim dos anos 1990, o número de jogadores de futebol brasileiros que jogam nos clubes profissionais internacionais aumenta constantemente. Os principais campeonatos europeus (Alemanha, Inglaterra, Espanha, França, Itália e Portugal são  muito procurados pelos jogadores brasileiros. A história das relações entre os territórios e as estratégias espaciais de recrutamento desenvolvidas pelos clubes de futebol europeus indica um sistema produtivo de jogadores brasileiros e canais migratórios muito organizados entre a Europa e o Brasil.Since the end of the 1990s, the number of Brazilian footballers playing in the international professional clubs increases constantly. The principal European championships (Germany, England, Spain, France, Italy and Portugal are very courted by the Brazilian players. The history

  1. Origin of epithermal Ag-Au-Cu-Pb-Zn mineralization in Guanajuato, Mexico

    Science.gov (United States)

    Mango, Helen; Arehart, Greg; Oreskes, Naomi; Zantop, Half

    2014-01-01

    The Guanajuato epithermal district is one of the largest silver producers in Mexico. Mineralization occurs along three main vein systems trending dominantly northwest-southeast: the central Veta Madre, the La Luz system to the northwest, and the Sierra system to the east. Mineralization consists dominantly of silver sulfides and sulfosalts, base metal sulfides (mostly chalcopyrite, galena, sphalerite, and pyrite), and electrum. There is a broad zonation of metal distribution, with up to 10 % Cu+Pb+Zn in the deeper mines along the northern and central portions of the Veta Madre. Ore occurs in banded veins and breccias and as stockworks, with gangue composed dominantly of quartz and calcite. Host rocks are Mesozoic sedimentary and intrusive igneous rocks and Tertiary volcanic rocks. Most fluid inclusion homogenization temperatures are between 200 and 300 °C, with salinities below 4 wt.% NaCl equivalent. Fluid temperature and salinity decreased with time, from 290 to 240 °C and from 2.5 to 1.1 wt.% NaCl equivalent. Relatively constant fluid inclusion liquid-to-vapor ratios and a trend of decreasing salinity with decreasing temperature and with increasing time suggest dilution of the hydrothermal solutions. However, evidence of boiling (such as quartz and calcite textures and the presence of adularia) is noted along the Veta Madre, particularly at higher elevations. Fluid inclusion and mineralogical evidence for boiling of metal-bearing solutions is found in gold-rich portions of the eastern Sierra system; this part of the system is interpreted as the least eroded part of the district. Oxygen, carbon, and sulfur isotope analysis of host rocks, ore, and gangue minerals and fluid inclusion contents indicate a hydrothermal fluid, with an initial magmatic component that mixed over time with infiltrating meteoric water and underwent exchange with host rocks. Mineral deposition was a result of decreasing activities of sulfur and oxygen, decreasing temperature, increasing p

  2. Moderniser la démarche visant la qualité de l'eau au Brésil | CRDI ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    20 sept. 2017 ... Leishmaniose : maladie sans frontières. Une mouche porteuse d'un parasite mortel hante la jungle des chutes d'Iguazu, qui marque la triple frontière entre le Brésil, l'Argentine et le. Voir davantageLeishmaniose : maladie sans frontières ...

  3. Crystal structure and electrical conductivity of {alpha}'''-[BEDT-TTF]{sub 12}[Cu{sub 2}Br{sub 4}]{sub 3} (BEDT-TTF=bis(ethylenedithio)tetrathiafulvalene)

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, Kazuya, E-mail: kkubo@m.tains.tohoku.ac.j [Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, Miyagi 980-8578 (Japan); Miyasaka, Hitoshi; Yamashita, Masahiro [Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, Miyagi 980-8578 (Japan)

    2010-06-01

    A new non-integer valence salt based on bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) with a dianionic dinuclear cupper(I) complex, {alpha}'''-[BEDT-TTF]{sub 12}(Cu{sup I}{sub 2}Br{sub 4}){sub 3}, was selectively synthesized by a diffusion of BEDT-TTF in tetrahydrofurane (THF) and a mixture of Cu{sup II}X{sub 2} (X=Br or Cl) in methanol. An alternating stacking arrangement of the BEDT-TTF layers and inorganic layers of the Cu{sup I}{sub 2}Br{sub 4}{sup 2-} anions is formed, where the BEDT-TTF layer involves six crystallographically independent molecules. Overlap integral calculation among BEDT-TTF donors in the salt suggests the existence of two-dimensional interactions among the donors. The compound exhibits semiconducting behavior in the wide range of temperature of room temperature to 2 K ({rho}{sub r.t.}=0.3 {Omega} cm, E{sub a}=0.08 eV in a crystal) without structural phase transition at ambient pressure.

  4. Magmatic-hydrothermal fluid evolution of the Dalli porphyry Cu-Au deposit; using Amphibole and Plagioclas mineral chemistry

    Directory of Open Access Journals (Sweden)

    Houshang Pourkaseb

    2017-07-01

    Full Text Available Introduction The formation of porphyry copper deposits is attributed to the shallow emplacement, and subsequent cooling of the hydrothermal system of porphyritic intrusive rocks (Titley and Bean, 1981. These deposits have usually been developed along the chain of subduction-related volcanic and calc-alkalin batholiths (Sillitoe, 2010. Nevertheless, it is now confirmed that porphyry copper systems can also form in collisional and post collisional settings (Zarasvandi et al., 2015b. Detailed studies on the geochemical features of ore-hosting porphyry Cu-Mo-Au intrusions indicate that they are generally adakitic, water and sulfur- riched, and oxidized (Wang et al., 2014. For example, high oxygen fugacity of magma has decisive role in transmission of copper and gold to the porphyry systems as revealed in (Wang et al., 2014. In this regard, the present work deals with the mineral chemistry of amphibole and plagioclase in the Dalli porphyry Cu-Au deposit. The data is used to achieve the physical and chemical conditions of magma and its impact on mineralization. Moreover, the results of previous studies on the hydrothermal system of the Dalli deposit such as Raman laser spectroscopy and fluid inclusion studies are included for determination of the evolution from magmatic to hydrothermal conditions. Materials and methods In order to correctly characterize the physical and chemical conditions affecting the trend of mineralization, 20 least altered and fractured samples of diorite and quartz-diorite intrusions were chosen from boreholes. Subsequently, 20 thin-polished sections were prepared in the Shahid Chamran University of Ahvaz. Finally, mineral chemistry of amphibole and plagioclase were determined using electron micro probe analyses (EMPA in the central lab of the Leoben University. Results Amphibole that is one of the the main rock-forming minerals can form in a wide variety of igneous and metamorphic rocks. Accordingly, amphibole chemistry can be

  5. Geology and mineralogy of the Au-As (Ag-Pb-Zn-Cu-Sb polymetallic deposit of Valiña-Azúmara (Lugo, NW Spain

    Directory of Open Access Journals (Sweden)

    Martínez-Abad, I.

    2015-12-01

    Full Text Available Valiña-Azúmara is a polymetallic Au-As (Ag-Pb-Zn-Cu-Sb deposit, located in the province of Lugo (NW Spain, that was mined for arsenic at the beginning of the 20th century. The mineralization is hosted in a Variscan thrust fault with a dip direction of N247-261ºE, and N-S and NE-SW Late-Variscan faults. These structures are hosted in black slates, Cambrian in age. To a lesser extent, the mineralization also occurs disseminated within narrow, weakly silicified and sericited selvages. Mineralization is divided into two hypogene stages. The first consists of quartz, calcite, rutile, sericite, arsenopyrite and pyrite. Two types of pyrite (Py-I and Py-II are defined according to their chemical and textural characteristics. Py-II occurs as overgrowth of previous Py-I crystals. Py-II is As-rich (≤1.7 wt.% and often contains traces of Te, Zn, Cu, Bi, Sb and Au. The mineralized drill core sections show a significant correlation between Au and As. This is due to Au occurring as invisible Au within the Py-II grains, with contents of up to 176 ppm. The Au/As ratios of Py-II indicate that Au was deposited as Au1+, as solid solution within the pyrite structure. The second stage of mineralization is enriched in Ag-Pb-Zn-Cu-Sb, replacing the first stage, and consists of quartz, calcite, chlorite, sphalerite, jamesonite, Ag-rich tetrahedrite, freibergite, chalcopyrite, pyrrhotite and galena. Although jamesonite shows traces of Ag, the Cu-Ag sulfosalts are the main carriers of the Ag mineralization in the deposit, with contents that vary from 13.7 to 23.9 wt.% of Ag. In the most superficial levels of the area, secondary Fe oxide and hydroxide, scorodite and anglesite developed due to the oxidation of the ore.Valiña-Azúmara es un yacimiento filoniano de Au-As (Ag-Pb-Zn-Cu-Sb situado en la provincia de Lugo (NO España, que fue explotado por arsénico a principios del siglo XX. La mineralización se encuentra encajada en un cabalgamiento Varisco de direcci

  6. High temperature gas-solid reactions in calc-silicate Cu-Au skarn formation; Ertsberg, Papua Province, Indonesia

    Science.gov (United States)

    Henley, Richard W.; Brink, Frank J.; King, Penelope L.; Leys, Clyde; Ganguly, Jibamitra; Mernagh, Terrance; Middleton, Jill; Renggli, Christian J.; Sieber, Melanie; Troitzsch, Ulrike; Turner, Michael

    2017-12-01

    The 2.7-3 Ma Ertsberg East Skarn System (Indonesia), adjacent to the giant Grasberg Porphyry Copper deposit, is part of the world's largest system of Cu -Au skarn deposits. Published fluid inclusion and stable isotope data show that it formed through the flux of magma-derived fluid through contact metamorphosed carbonate rock sequences at temperatures well above 600° C and pressures of less than 50 MPa. Under these conditions, the fluid has very low density and the properties of a gas. Combining a range of micro-analytical techniques, high-resolution QEMSCAN mineral mapping and computer-assisted X-ray micro-tomography, an array of coupled gas-solid reactions may be identified that controlled reactive mass transfer through the 1 km3 hydrothermal skarn system. Vacancy-driven mineral chemisorption reactions are identified as a new type of reactive transport process for high-temperature skarn alteration. These gas-solid reactions are maintained by the interaction of unsatisfied bonds on mineral surfaces and dipolar gas-phase reactants such as SO2 and HCl that are continuously supplied through open fractures and intergranular diffusion. Principal reactions are (a) incongruent dissolution of almandine-grossular to andradite and anorthite (an alteration mineral not previously recognized at Ertsberg), and (b) sulfation of anorthite to anhydrite. These sulfation reactions also generate reduced sulfur with consequent co-deposition of metal sulfides. Diopside undergoes similar reactions with deposition of Fe-enriched pyroxene in crypto-veins and vein selvedges. The loss of calcium from contact metamorphic garnet to form vein anhydrite necessarily results in Fe-enrichment of wallrock, and does not require Fe-addition from a vein fluid as is commonly assumed.

  7. LA-ICP-MS U-Th-Pb Dating and Trace Element Geochemistry of Allanite: Implications on the Different Skarn Metallogenesis between the Giant Beiya Au and Machangqing Cu-Mo-(Au Deposits in Yunnan, SW China

    Directory of Open Access Journals (Sweden)

    Yu Fu

    2017-12-01

    Full Text Available The giant Beiya Au skarn deposit and Machangqing porphyry Cu-Mo-(Au deposit are located in the middle part of the Jinshajiang–Ailaoshan alkaline porphyry metallogenic belt. The Beiya deposit is the largest Au skarn deposit in China, whilst the Machangqing deposit comprises a well-developed porphyry-skarn-epithermal Cu-Mo-(Au mineral system. In this paper, we present new allanite U-Th-Pb ages and trace element geochemical data from the two deposits and discuss their respective skarn metallogenesis. Based on the mineral assemblage, texture and Th/U ratio, the allanite from the Beiya and Machangqing deposits are likely hydrothermal rather than magmatic. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS allanite U-Th-Pb dating has yielded Th-Pb isochron ages of 33.4 ± 4.6 Ma (MSWD = 0.22 (Beiya and 35.4 ± 9.8 Ma (MSWD = 0.26 (Machangqing, representing the retrograde alteration and magnetite skarn mineralization age of the two deposits. The Beiya and Machangqing alkali porphyry-related mineralization are synchronous and genetically linked to the magmatic hydrothermal activities of the Himalayan orogenic event. Major and trace element compositions reveal that the Beiya allanite has higher Fe3+/(Fe3+ + Fe2+ ratios, U content and Th content than the Machangqing allanite, which indicate a higher oxygen fugacity and F content for the ore-forming fluids at Beiya. Such differences in the ore-forming fluids may have contributed to the different metallogenic scales and metal types in the Beiya and Machangqing deposit.

  8. Une théorie enracinée du changement stratégique des entreprises réussies dans des environnements hostiles: Le cas de l’embraco au Brésil

    OpenAIRE

    2007-01-01

    Au Brésil, l'étude sur le processus du changement stratégique organisationnel, en général, ne considère pas les implications du changement dans la performance organisationnel. À son tour, les études qui ont comme objectif expliquer les variations de performance ne considèrent pas le processus du changement stratégique sous-jacent. Cette étude essaie de suppléer cette lacune théorique dans la mesure où elle fournit une explication pour le changement stratégique des entreprises qui possèdent l'...

  9. Musique populaire et dictature militaire au Brésil : dynamiques contestataires et logiques de marché (1964-1985)

    OpenAIRE

    Fléchet, Anaïs; Napolitano, Marcos

    2015-01-01

    Souvent présentée comme un symbole de résistance, la Musique Populaire Brésilienne a été investie de multiples significations politiques pendant la dictature militaire (1964-1985). L’examen de la production (disques, spectacles, mais aussi films et fictions télévisées) et des écrits critiques, les archives de la censure et des services chargés de la surveillance politique, ainsi que les sources diplomatiques mettent à jour la complexité des pratiques, des acteurs et des usages politiques de l...

  10. Microstructural, electrical and frequency-dependent properties of Au/p-Cu2ZnSnS4/n-GaN heterojunction.

    Science.gov (United States)

    Rajagopal Reddy, V; Janardhanam, V; Won, Jonghan; Choi, Chel-Jong

    2017-08-01

    An Au/Cu2ZnSnS4 (CZTS)/n-GaN heterojunction (HJ) is fabricated with a CZTS interlayer and probed its chemical states, structural, electrical and frequency-dependent characteristics by XPS, TEM, I-V and C-V measurements. XPS and TEM results confirmed that the CZTS films are formed on the n-GaN surface. The band gap of deposited CZTS film is found to be 1.55eV. The electrical properties of HJ correlated with the Au/n-GaN Schottky junction (SJ). The Au/CZTS/n-GaN HJ reveals a good rectification nature with high barrier height (0.82eV) compared to the Au/n-GaN SJ (0.69eV), which suggests the barrier height is influenced by the CZTS interlayer. The barrier height values assessed by I-V, Cheung's and Norde functions are closely matched with one other, thus the methods used here are reliable and valid. The extracted interface state density (NSS) of Au/CZTS/n-GaN HJ is lower compared to the Au/n-GaN SJ that suggests the CZTS interlayer plays an important role in the reduction of NSS. Moreover, the capacitance-frequency (C-f) and conductance-frequency (G-f) characteristics of SJ and HJ are measured in the range of 1kHz-1MHz, and found that the capacitance and conductance strappingly dependent on frequency. It is found that the NSS estimated from C-f and G-f characteristics is lower compared to those estimated from I-V characteristics. Analysis confirmed that Poole-Frenkel emission dominates the reverse leakage current in both SJ and HJ, probably related to the structural defects and trap levels in the CZTS interlayer. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Control of Surface Plasmon Resonance of Au/SnO2 by Modification with Ag and Cu for Photoinduced Reactions under Visible-Light Irradiation over a Wide Range.

    Science.gov (United States)

    Tanaka, Atsuhiro; Hashimoto, Keiji; Kominami, Hiroshi

    2016-03-18

    Gold particles supported on tin(IV) oxide (0.2 wt% Au/SnO2) were modified with copper and silver by the multistep photodeposition method. Absorption around λ=550 nm, attributed to surface plasmon resonance (SPR) of Au, gradually shifted to longer wavelengths on modification with Cu and finally reached λ=620 nm at 0.8 wt% Cu. On the other hand, the absorption shifted to shorter wavelength with increasing amount of Ag and reached λ=450 nm at 0.8 wt% Ag. These Cu- and Ag-modified 0.2 wt% Au/SnO2 materials (Cu-Au/SnO2 and Ag-Au/SnO2) and 1.0 wt% Au/SnO2 were used for mineralization of formic acid to carbon dioxide in aqueous suspension under irradiation with visible light from a xenon lamp and three kinds of light-emitting diodes with different wavelengths. The reaction rates for the mineralization of formic acid over these materials depend on the wavelength of light. Apparent quantum efficiencies of Cu-Au/SnO2, Au/SnO2, and Ag-Au/SnO2 reached 5.5% at 625 nm, 5.8% at 525 nm, and 5.1% at 450 nm, respectively. These photocatalysts can also be used for selective oxidation of alcohols to corresponding carbonyl compounds in aqueous solution under visible-light irradiation. Broad responses to visible light in formic acid mineralization and selective alcohol oxidation were achieved when the three materials were used simultaneously. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Dinuclear Metallacycles with Single M-X-M Bridges (X = Cl-, Br-; M = Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II)): Strong Antiferromagnetic Superexchange Interactions.

    Science.gov (United States)

    Reger, Daniel L; Pascui, Andrea E; Foley, Elizabeth A; Smith, Mark D; Jezierska, Julia; Wojciechowska, Agnieszka; Stoian, Sebastian A; Ozarowski, Andrew

    2017-03-06

    A series of monochloride-bridged, dinuclear metallacycles of the general formula [M2(μ-Cl)(μ-L)2](ClO4)3 have been prepared using the third-generation, ditopic bis(pyrazolyl)methane ligands L = m-bis[bis(1-pyrazolyl)methyl]benzene (Lm), M = Cu(II), Zn(II), and L = m-bis[bis(3,5-dimethyl-1-pyrazolyl)methyl]benzene (Lm*), M = Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II). These complexes were synthesized from the direct reactions of M(ClO4)2·6H2O, MCl2, and the ligand, Lm or Lm*, in the appropriate stoichiometric amounts. Three analogous complexes of the formula [M2(μ-Cl)(μ-L)2](BF4)3, L = Lm, M = Cu(II), and L = Lm*, M = Co(II), Cu(II), were prepared from the reaction of [M2(μ-F)(μ-L)2](BF4)3 and (CH3)3SiCl. The bromide-bridged complex [Cu2(μ-Br)(μ-Lm*)2](ClO4)3 was prepared by the first method. Three acyclic complexes, [Co2(μ-Lm)μ-Cl4], [Co2(μ-Lm*)Cl4], and [Co2(μ-Lm*)Br4], were also prepared. The structures of all [M2(μ-X)(μ-L)2]3+ (X = Cl-, Br-) complexes have two ditopic bis(pyrazolyl)methane ligands bridging two metals in a metallacyclic arrangement. The fifth coordination site of the distorted trigonal bipyramidal metal centers is filled by a bridging halide ligand that has an unusual linear or nearly linear M-X-M angle. The NMR spectra of [Zn2(μ-Cl)(μ-Lm*)2](ClO4)3 and especially [Cd2(μ-Cl)(μ-Lm*)2](ClO4)3 demonstrate that the metallacycle structure is maintained in solution. Solid state magnetic susceptibility data for the copper(II) compounds show very strong antiferromagnetic exchange interactions, with -J values of 536 cm-1 for [Cu2(μ-Cl)(μ-Lm)2](ClO4)3·xCH3CN, 720 cm-1 for [Cu2(μ-Cl)(μ-Lm*)2](ClO4)3, and 945 cm-1 for [Cu2(μ-Br)(μ-Lm*)2](ClO4)3·2CH3CN. Smaller but still substantial antiferromagnetic interactions are observed with other first row transition metals, with -J values of 98 cm-1 for [Ni2(μ-Cl)(μ-Lm*)2](ClO4)3, 55 cm-1 for [Co2(μ-Cl)(μ-Lm*)2](ClO4)3, and 34 cm-1 for [Fe2(μ-Cl)(μ-Lm*)2](ClO4)3. EPR spectra of [Cu

  13. Engineering of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} grain boundary Josephson junctions by Au nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Michalowski, P.; Schmidt, M.; Schmidl, F.; Grosse, V.; Kuhwald, D.; Katzer, C.; Seidel, P. [Institut fuer Festkoerperphysik, Universitaet Jena, Helmholtzweg 5, 07743 Jena (Germany); Huebner, U. [Institute of Photonic Technology, Albert-Einstein-Strasse 9, 07745 Jena (Germany)

    2011-08-15

    We prepared and investigated grain boundary Josephson junctions based on SrTiO{sub 3} bicrystal substrates. During the deposition of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) gold nanocrystals forming from an intermediate gold layer can modify the crystalline structure and thus the properties of the YBCO grain boundaries. The variation of the film thickness of the Au seed layer changes the growth conditions of the YBCO film and the Au nanocrystals. The values of the characteristic I{sub C}R{sub N} product do not change whereas the values of the critical current I{sub C} decrease. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. The adsorption and diffusion behavior of noble metal adatoms (Pd, Pt, Cu, Ag and Au) on a MoS2 monolayer: a first-principles study.

    Science.gov (United States)

    Wu, Ping; Yin, Naiqiang; Li, Peng; Cheng, Wenjing; Huang, Min

    2017-08-09

    First-principles calculations based on periodic density functional theory (DFT) have been used to investigate the geometries, electronic structures, magnetic properties and diffusion behaviors of different noble metal adatoms (Pd, Pt, Cu, Ag and Au) on MoS2 monolayers. The results demonstrate that these adatoms can chemically adsorb on MoS2 monolayers. The band gaps of MoS2 monolayers with a Pd or Pt atom adsorbed are reduced owing to impurity states that emerge simultaneously within the gap region of the pristine MoS2 monolayer. The unpaired electrons in MoS2 monolayers with a Cu, Ag or Au atom adsorbed are spin polarized, resulting in total magnetic moments of 1.0 μB per supercell, which is caused by the strong hybridization between the metal adatoms and surrounding Mo or S atoms. Long-range antiferromagnetic (AFM) coupling has been observed between group IB metal adatoms. Due to charge transfer between adatoms and the MoS2 host, the work functions were modulated upon adsorption of noble metals. In addition, the diffusion behaviors of noble metal adatoms on the MoS2 monolayer suggest that Cu, Pd and Pt atoms favor the formation of a metal nanotemplate on the MoS2 monolayer, and Ag and Au are likely to form isolated particles in the initial growth stage. These findings may provide useful guidance to extend the potential applications of MoS2 in low-dimensional nanoelectronic and spintronic devices.

  15. A comparative study of Cu, Ag and Au doped CeO{sub 2} in the total oxidation of volatile organic compounds (VOCs)

    Energy Technology Data Exchange (ETDEWEB)

    Aboukaïs, Antoine, E-mail: aboukais@univ-littoral.fr [Unité de Chimie Environnementale et Interactions sur le Vivant EA 4492, ULCO, Equipe de Catalyse-UCEIV, MREI, 59140, Dunkerque (France); Skaf, Mira, E-mail: miraskaf@hotmail.com [Unité de Chimie Environnementale et Interactions sur le Vivant EA 4492, ULCO, Equipe de Catalyse-UCEIV, MREI, 59140, Dunkerque (France); Department of Chemistry, Faculty of Sciences, University of Balamand, P.O. Box 100, Deir El Balamand, Kelhat-Tripoli (Lebanon); Hany, Sara, E-mail: sarahani@hotmail.com [Unité de Chimie Environnementale et Interactions sur le Vivant EA 4492, ULCO, Equipe de Catalyse-UCEIV, MREI, 59140, Dunkerque (France); Cousin, Renaud, E-mail: Renaud.Cousin@univ-littoral.fr [Unité de Chimie Environnementale et Interactions sur le Vivant EA 4492, ULCO, Equipe de Catalyse-UCEIV, MREI, 59140, Dunkerque (France); Aouad, Samer, E-mail: Samer.Aouad@balamand.edu.lb [Department of Chemistry, Faculty of Sciences, University of Balamand, P.O. Box 100, Deir El Balamand, Kelhat-Tripoli (Lebanon); Labaki, Madona, E-mail: mlabaki@ul.edu.lb [Laboratory of Physical Chemistry of Materials (LCPM)/PR2N, Faculty of Sciences, Lebanese University, Fanar, PO Box 90656, Jdeidet El Metn (Lebanon); Abi-Aad, Edmond, E-mail: abiaad@univ-littoral.fr [Unité de Chimie Environnementale et Interactions sur le Vivant EA 4492, ULCO, Equipe de Catalyse-UCEIV, MREI, 59140, Dunkerque (France)

    2016-07-01

    Total oxidation of two Volatile Organic Compounds (VOCs), propylene and toluene, was investigated over M/CeO{sub 2} catalysts, where M is a metal from IB group (i.e. Au, Ag, Cu), prepared by two different methods: the conventional wet impregnation and the deposition-precipitation. The catalysts have been characterized by means of total surface area (BET), X-ray diffraction (XRD), electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), diffuse reflectance ultra-violet-visible spectroscopy (DR-UV/Vis), and temperature-programmed reduction (TPR), in order to explain the differences observed in their catalytic activity towards the studied reactions. By comparing the two different preparation methods, the presence of metal in high oxidation state for gold and silver, and the presence of clusters for copper were the main factors responsible for the high catalytic activity. This latter was also found to be related, when comparing the different IB metals, to the values of the oxidation/reduction potential of the redox couples of the different metals. - Highlights: • IB metals (Au, Ag and Cu) were supported on ceria (CeO{sub 2}) by two different methods. • The solids were tested as catalysts for total oxidation of propylene and toluene. • The deposition-precipitation is better for Au whereas for Ag and Cu it is the impregnation. • High oxidation states of gold and silver and clusters of copper enhanced catalytic behavior. • Catalytic activity is linked to the oxidation/reduction potential of the redox IB couples.

  16. Contrasting Cu-Au and Sn-W Granite Metallogeny through the Zircon Geochemical and Isotopic Record

    Science.gov (United States)

    Gardiner, Nicholas; Hawkesworth, Chris; Robb, Laurence; Whitehouse, Martin; Roberts, Nick; Kirkland, Chris

    2017-04-01

    Magmatic genesis and evolution - mediated by geodynamic setting - exert a primary control on the propensity of granites to be metal fertile. A revolution in our understanding of these petrogenetic processes has been made through a range of mineral-based tools, most notably the common accessory mineral zircon. There is consequently considerable interest in whether the geochemical and isotopic compositions of zircon can be applied to metallogenic problems. The paired magmatic belts of Myanmar have broadly contrasting metallogenic affinities (Sn-W versus Cu-Au), and are interpreted to have formed on the accretionary margin of the subducting Neo-Tethys Ocean. They therefore present the opportunity to geochemically compare and contrast the zircon compositions in two end-member types of granite-hosted mineral deposits generated in collisional settings. We present an integrated zircon isotope (U-Pb, Lu-Hf, O) and trace element dataset that fingerprint: (a) source; (b) redox conditions; and (c) degree of fractionation. These variables all impact on magma fertility, and our key question to address is whether they can be reliably traced and calibrated within the Myanmar zircon record. Granitoid-hosted zircons from the I-type copper arc have juvenile ɛHf (+7 to +12) and mantle-like δ18O (5.3 ‰), whereas zircons from the S-type tin belt have low ɛHf (-7 to -13) and heavier δ18O (6.2-7.7 ‰). Plotting Hf versus U/Yb reaffirms that the tin belt magmas contain greater crustal contributions than the copper arc rocks. Links between whole rock Rb/Sr and zircon Eu/Eu* highlights that the latter can be used to monitor magma fractionation in systems that crystallize plagioclase (low Sr/Y). Ce/Ce* and Eu/Eu* in zircon are thus sensitive to redox and fractionation respectively, and can be used to evaluate the sensitivity of zircons to the metallogenic affinity of their host rocks. Tin contents that exceed the solubility limit are required in order to make a magmatic

  17. Geology and reconnaissance stable isotope study of the Oyu Tolgoi porphyry Cu-Au system, South Gobi, Mongolia

    Science.gov (United States)

    Khashgerel, B.-E.; Rye, R.O.; Hedenquist, J.W.; Kavalieris, I.

    2006-01-01

    The Oyu Tolgoi porphyry Cu-Au system in the South Gobi desert, Mongolia, comprises five deposits that extend over 6 km in a north-northeast-oriented zone. They occur in a middle to late Paleozoic are terrane and are related to Late Devonian quartz monzodiorite intrusions. The Hugo Dummett deposits are the northernmost and deepest, with up to 1,000 m of premineral sedimentary and volcanic cover rock remaining. They are the largest deposits discovered to date and characterized by high-grade copper (>2.5% Cu) and gold (0.5-2 g/t) mineralization associated with intense quartz veining and several phases of quartz monzodiorite intruded into basaltic volcanic host rocks. Sulfide minerals in these deposits are zoned outward from a bornite-dominated core to chalcopyrite, upward to pyrite ?? enargite and covellite at shallower depth. The latter high-sulfidation-state sulfides are hosted by advanced argillic alteration mineral associations. This alteration is restricted mainly to dacitic ash-flow tuff that overlies the basaltic volcanic rock and includes ubiquitous quartz and pyrophyllite, kaolinite, plus late dickite veins, as well as K alunite, Al phosphate-sulfate minerals, zunyite, diaspore, topaz, corundum, and andalusite. A reconnaissance oxygen-hydrogen and sulfur isotope study was undertaken to investigate the origin of several characteristic alteration minerals in the Oyu Tolgoi system, with particular emphasis on the Hugo Dummett deposits. Based on the isotopic composition of O, H, and S (??18O(SO4) = 8.8-20.1???, ??D = -73 to -43???, ??34S = 9.8-17.9???), the alunite formed from condensation of magmatic vapor that ascended to the upper parts of the porphyry hydrothermal system, without involvement of significant amounts of meteoric water. The isotopic data indicate that pyrophyllite (??18O = 6.5-10.9???, ??D = -90 to -106???) formed from a magmatic fluid with a component of meteoric water. Muscovite associated with quartz monzodiorite intrusions occurs in the core

  18. Uranium-lead dating of hydrothermal zircon and monazite from the Sin Quyen Fe-Cu-REE-Au-(U) deposit, northwestern Vietnam

    Science.gov (United States)

    Li, Xiao-Chun; Zhou, Mei-Fu; Chen, Wei Terry; Zhao, Xin-Fu; Tran, MyDung

    2017-06-01

    The Sin Quyen deposit in northwestern Vietnam contains economic concentrations of Cu, Au and LREE, and sub-economic concentration of U. In this deposit, massive and banded replacement ores are hosted in Neoproterozoic metapelite. The paragenetic sequence includes sodic alteration (stage I), calcic-potassic alteration and associated Fe-REE-(U) mineralization (stage II), Cu-Au mineralization (stage III), and sulfide-(quartz-carbonate) veins (stage IV). The Sin Quyen deposit experienced an extensive post-ore metamorphic overprint, which makes it difficult to precisely determine the mineralization age. In this study, zircon and monazite U-Pb geochronometers and the Rb-Sr isochron method are used to constrain the timing of mineralization. Zircon grains in the ore are closely intergrown or texturally associated with hydrothermal minerals of stage II (e.g., garnet, allanite, and hedenbergite). They may contain primary fluid inclusions and display irregular zoning in cathodoluminescence (CL) images. Zircon grains are rich in U (688 to 2902 ppm) and poor in Th (0.2 to 2.9 ppm). Their δ18OV-SMOW values range from 11.9 to 14.0‰, higher than those of typical magmatic zircon. These textural and compositional features imply that zircon precipitated from 18O- and U-rich hydrothermal fluids, coeval with the minerals of stage II. Monazite occurs in close association with stage II magnetite and allanite and has low contents of Th (<2700 ppm), indicative of a hydrothermal origin. Hydrothermal zircon and monazite have indistinguishable U-Pb ages of 841 ± 12 and 836 ± 18 Ma, respectively, representing the timing of Fe-REE mineralization. There is no direct isotopic constraint on the timing of the Cu-Au mineralization, but geological observations suggest that the Cu-Au and Fe-REE ores most likely formed within a single evolved hydrothermal process. In the plot of 87Rb/86Sr vs. 87Sr/86Sr, the composition of bulk-ore and biotite separates from ore lie along a reference line for 30 Ma

  19. Enhanced Ultraviolet Random Lasing from Au/MgO/ZnO Heterostructure by Introducing p-Cu2O Hole-Injection Layer.

    Science.gov (United States)

    Zhang, Cen; Zhang, Juan; Liu, Weizhen; Xu, Haiyang; Hou, Shuai; Wang, Chunliang; Yang, Liu; Wang, Zhongqiang; Wang, Xinhua; Liu, Yichun

    2016-11-23

    Ultraviolet light-emitting devices (LEDs) were fabricated on the basis of Au/MgO/ZnO metal/insulator/semiconductor (MIS) heterostructures. By introducing a thermally oxidized p-type Cu2O hole-injection layer into this MIS structure, enhanced ultraviolet electroluminescence (EL) and random lasing with reduced threshold injection current are achieved. The enhancement mechanism is attributed to effective hole transfer from p-Cu2O to i-MgO under forward bias, which increases the initial carrier concentration of MgO dielectric layer and further promotes "impact-ionization" effect induced carrier generation and injection. The current study proposes a new and effective route to improve the EL performance of MIS junction LEDs via introducing extrinsic hole suppliers.

  20. Substitution of Au or Hg into BaTl2 and BaIn2. New ternary examples of smaller CeCu2-type intermetallic phases.

    Science.gov (United States)

    Dai, Jing-Cao; Corbett, John D

    2006-03-06

    The compounds BaAu(0.40(2))Tl(1.60(7)) (1), BaAu(0.36(4))In(1.64(4)) (2), and BaHg(0.92(2))In(1.08(2)) (3) have been prepared by high-temperature techniques. Single-crystal X-ray diffraction shows that these have the orthorhombic CeCu(2)-type structure, Imma, Z = 4 (a = 5.140(1), 5.104(1), 5.145(1) A; b = 8.317(2), 8.461(2), 8.373(2) A; c = 8.809(2), 8.580(2), 8.715(2) A, respectively). The structure consists of a four-linked honeycomblike polyanion (4(2)6(3)8) of infinity3[Tr2]2- (Tr = In or Tl) with encapsulated Ba2+ cations. The Au or Hg randomly replace Tr in a single type of site. The two gold phases exhibit appreciable nonstoichiometry ranges. Band calculations (EHTB) demonstrate that the three compounds are electron-poor and metallic, and the latter has been confirmed for 1 through resistivity and magnetic susceptibility measurements. The orthorhombic structure of 1 contrasts with the hexagonal structure of BaTl2 (CaIn2-type, P6(3)/mmc), a change that appears to be driven by substitution of the smaller Au atoms into the polyanion network. Relativistic effects for the heavier Au and Hg are evidently responsible for decreases in lattice parameters and bond lengths from BaIn2 to those in isostructural 2 and 3.

  1. Les publics du livre de poche dans la construction du discours sur la démocratisation culturelle au Brésil

    OpenAIRE

    Righini de Souza, Willian Eduardo

    2015-01-01

    Le succès du livre de poche au XXe siècle, avec des collections atteignant des millions d’exemplaires vendus, a fait s’interroger ses partisans tout autant que ses détracteurs sur la possibilité qu’une politique d’encouragement à la lecture passant par une baisse des prix, l’apparition de nouveaux points de vente destinés à toucher ceux qui n’achètent jamais ou rarement des livres, et ainsi susciter l’émergence de nouveaux lecteurs. L’idéal de démocratisation culturelle, qui touchait égalemen...

  2. 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...

  3. Novel metalloantimalarials: Transmission blocking effects of water soluble Cu(I), Ag(I) and Au(I) phosphane complexes on the murine malaria parasite Plasmodium berghei.

    Science.gov (United States)

    Tapanelli, Sofia; Habluetzel, Annette; Pellei, Maura; Marchiò, Luciano; Tombesi, Alessia; Capparè, Ambra; Santini, Carlo

    2017-01-01

    The water soluble phosphane complexes [M(L)4]PF6 (M=Cu(I), Ag(I)) and [Au(L)4]Cl (L=thp (tris(hydroxymethyl)phosphane) or PTA (1,3,5-triaza-7-phosphaadamantane)) showed notable in vitro activity against Plasmodium early sporogonic stages, the sexual forms of the malaria parasite that are responsible for infection of the mosquito vector. Effects varied according to both, the type of metal and phosphane ligands. [Ag(thp)4]PF6 was the best performing complex exhibiting a half inhibitory concentration (IC50) value in the low micromolar range (0.3-15.6μM). The silver complex [Ag(thp)4]PF6 was characterized by X-ray crystallography revealing that the structure comprises the cationic complex [Ag(thp)4]+, the PF6- anion, and a water molecule of crystallization. Our results revealed that Cu(I), Ag(I) and Au(I) phosphanes complexes elicited similar activity profiles showing potential for the development of antimalarial, transmission blocking compounds. Molecules targeting the sexual parasite stages in the human and/or mosquito host are urgently needed to complement current artemisinin based treatments and next generation antimalarials in a vision not only to cure the disease but to interrupt its transmission. Copyright © 2016. Published by Elsevier Inc.

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

    Science.gov (United States)

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

    2003-03-01

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

  5. Geochemical Data for Samples Collected in 2007 Near the Concealed Pebble Porphyry Cu-Au-Mo Deposit, Southwest Alaska

    Science.gov (United States)

    Fey, David L.; Granitto, Matthew; Giles, Stuart A.; Smith, Steven M.; Eppinger, Robert G.; Kelley, Karen D.

    2008-01-01

    In the summer of 2007, the U.S. Geological Survey (USGS) began an exploration geochemical research study over the Pebble porphyry copper-gold-molydenum (Cu-Au-Mo) deposit in southwest Alaska. The Pebble deposit is extremely large and is almost entirely concealed by tundra, glacial deposits, and post-Cretaceous volcanic and volcaniclastic rocks. The deposit is presently being explored by Northern Dynasty Minerals, Ltd., and Anglo-American LLC. The USGS undertakes unbiased, broad-scale mineral resource assessments of government lands to provide Congress and citizens with information on national mineral endowment. Research on known deposits is also done to refine and better constrain methods and deposit models for the mineral resource assessments. The Pebble deposit was chosen for this study because it is concealed by surficial cover rocks, it is relatively undisturbed (except for exploration company drill holes), it is a large mineral system, and it is fairly well constrained at depth by the drill hole geology and geochemistry. The goals of the USGS study are (1) to determine whether the concealed deposit can be detected with surface samples, (2) to better understand the processes of metal migration from the deposit to the surface, and (3) to test and develop methods for assessing mineral resources in similar concealed terrains. This report presents analytical results for geochemical samples collected in 2007 from the Pebble deposit and surrounding environs. The analytical data are presented digitally both as an integrated Microsoft 2003 Access? database and as Microsoft 2003 Excel? files. The Pebble deposit is located in southwestern Alaska on state lands about 30 km (18 mi) northwest of the village of Illiamna and 320 km (200 mi) southwest of Anchorage (fig. 1). Elevations in the Pebble area range from 287 m (940 ft) at Frying Pan Lake just south of the deposit to 1146 m (3760 ft) on Kaskanak Mountain about 5 km (5 mi) to the west. The deposit is in an area of

  6. σ-Aromatic cyclic M3(+) (M = Cu, Ag, Au) clusters and their complexation with dimethyl imidazol-2-ylidene, pyridine, isoxazole, furan, noble gases and carbon monoxide.

    Science.gov (United States)

    Pan, Sudip; Saha, Ranajit; Mandal, Subhajit; Chattaraj, Pratim K

    2016-04-28

    The σ-aromaticity of M3(+) (M = Cu, Ag, Au) is analyzed and compared with that of Li3(+) and a prototype σ-aromatic system, H3(+). Ligands (L) like dimethyl imidazol-2-ylidene, pyridine, isoxazole and furan are employed to stabilize these monocationic M3(+) clusters. They all bind M3(+) with favorable interaction energy. Dimethyl imidazol-2-ylidene forms the strongest bond with M3(+) followed by pyridine, isoxazole and furan. Electrostatic contribution is considerably more than that of orbital contribution in these M-L bonds. The orbital interaction arises from both L → M σ donation and L ← M back donation. M3(+) clusters also bind noble gas atoms and carbon monoxide effectively. In general, among the studied systems Au3(+) binds a given L most strongly followed by Cu3(+) and Ag3(+). Computation of the nucleus-independent chemical shift (NICS) and its different extensions like the NICS-rate and NICS in-plane component vs. NICS out-of-plane component shows that the σ-aromaticity in L bound M3(+) increases compared to that of bare clusters. The aromaticity in pyridine, isoxazole and furan bound Au3(+) complexes is quite comparable with that in the recently synthesized Zn3(C5(CH3)5)3(+). The energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital also increases upon binding with L. The blue-shift and red-shift in the C-O stretching frequency of M3(CO)3(+) and M3(OC)3(+), respectively, are analyzed through reverse polarization of the σ- and π-orbitals of CO as well as the relative amount of OC → M σ donation and M → CO π back donation. The electron density analysis is also performed to gain further insight into the nature of interaction.

  7. Resonant core spectroscopies of the charge transfer interactions between C60 and the surfaces of Au(111), Ag(111), Cu(111) and Pt(111)

    Science.gov (United States)

    Gibson, Andrew J.; Temperton, Robert H.; Handrup, Karsten; O'Shea, James N.

    2017-03-01

    Charge transfer interactions between C60 and the metal surfaces of Ag(111), Cu(111), Au(111) and Pt(111) have been studied using synchrotron-based photoemission, resonant photoemission and X-ray absorption spectroscopies. By placing the X-ray absorption and valence band spectra on a common binding energy scale, the energetic overlap of the unoccupied molecular orbitals with the density of states of the underlying metal surface have been assessed in the context of possible charge transfer pathways. Resonant photoemission and resonant Auger data, measuring the valence region as a function of photon energy for C60 adsorbed on Au(111) reveals three constant high kinetic energy features associated with Auger-like core-hole decay involving an electron transferred from the surface to the LUMO of the molecule and electrons from the three highest occupied molecular orbitals, respectively and in the presence of ultra-fast charge transfer of the originally photoexcited molecule to the surface. Data for the C60/Ag(111) surface reveals an additional Auger-like feature arising from a core-hole decay process involving more than one electron transferred from the surface into the LUMO. An analysis of the relative abundance of these core-hole decay channels estimates that on average 2.4 ± 0.3 electrons are transferred from the Ag(111) surface into the LUMO. A core-hole clock analysis has also been applied to assess the charge transfer coupling in the other direction, from the molecule to the Au(111) and Ag(111) surfaces. Resonant photoemission and resonant Auger data for C60 molecules adsorbed on the Pt(111) and Cu(111) surfaces are shown to exhibit no super-Auger features, which is attributed to the strong modification of the unoccupied molecular orbitals arising from stronger chemical coupling of the molecule to the surface.

  8. Regional setting and characteristics of the Neoproterozoic Wadi Hamama Zn-Cu-Ag-Au prospect: evidence for an intra-oceanic island arc-hosted volcanogenic hydrothermal system

    Science.gov (United States)

    Abd El-Rahman, Yasser; Surour, Adel A.; El-Manawi, Abdel Hamid W.; El-Dougdoug, Abdel-Monem A.; Omar, Sayed

    2015-04-01

    The Wadi Hamama area is a volcanogenic Zn-Cu-Au-Ag prospect. It is hosted by a Neoproterozoic bimodal-mafic sequence, which comprises basalt, dacite and rhyolite along with volcaniclastic rocks. The rocks have a low-K tholeiitic affinity and are enriched in large ion lithophile elements over high field strength elements, which indicated their formation in an intra-oceanic island arc tectonic setting. The area was intruded by a tonalite-trondhjemite body, which has an intra-oceanic island arc affinity and later by diorite, which has a cordilleran-margin geochemical affinity. These rock units were intruded by post-tectonic granite dykes, which have a within-plate geochemical signature. There is a quartz-carbonate horizon extending along the contact between the basalt and the volcaniclastic rocks, mainly banded and lapilli tuffs. This horizon is of exhalative origin and is underlain by a mushroom-shaped alteration zone extending from the horizon down to the massive basalt. The footwall alteration is characterized by a silica-rich core surrounded by a thick chlorite sheath. Both the quartz-carbonate horizon and the footwall-altered rocks enclose historical trenches and pits. Sulfide-rich core samples are enriched in Zn, relative to Cu, and in Ag, which indicates the low-temperature nature of the hydrothermal system. The prospect was affected by supergene processes, which led to the widespread occurrence of secondary copper minerals and gold enrichment relative to the leached base metals, especially Zn. The prospect formed through a limited rifting of an intra-oceanic island arc which resulted in the formation of a small-scale volcanogenic Zn-Cu-Ag-Au prospect.

  9. Saltwater ecotoxicology of Ag, Au, CuO, TiO2, ZnO and C60 engineered nanoparticles: An overview.

    Science.gov (United States)

    Minetto, D; Volpi Ghirardini, A; Libralato, G

    2016-01-01

    This review paper examined 529 papers reporting experimental nanoecotoxicological original data. Only 126 papers referred to saltwater environments (water column and sediment) including a huge variety of species (n=51), their relative endpoints and engineered nanoparticles (ENPs) (n=38). We tried to provide a synthetic overview of the ecotoxicological effects of ENPs from existing data, refining papers on the basis of cross-cutting selection criteria and supporting a "mind the gap" approach stressing on missing data for hazard and risk assessment. After a codified selection procedure, attention was paid to Ag, Au, CuO, TiO2, ZnO and C60 ENPs, evidencing and comparing the observed nanoecotoxicity range of effect. Several criticisms were evidenced: i) some model organisms are overexploited like microalgae and molluscs compared to annelids, echinoderms and fish; ii) underexploited model organisms: mainly bacteria and fish; iii) exposure scenario variability: high species-specific and ENP scenarios including organism life stage and way of administration/spiking of toxicants; iv) scarce comparability between results due to exposure scenario variability; v) micro- and mesocosms substantially unexplored; vi) mixture effects: few examples are available only for ENPs and traditional pollutants; mixtures of ENPs have not been investigated yet; vii) effects of ions and ENPs: nAg, nCuO and nZnO toxicity aetiology is still a matter of discussion; viii) size and morphology effects of ENPs: scarcely investigated, justified and understood. Toxicity results evidenced that: nAu>nZnO>nAg>nCuO>nTiO2>C60. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Prediction of hidden Au and Cu-Ni ores from depleted mines in Northwestern China: four case studies of integrated geological and geophysical investigations

    Science.gov (United States)

    Shen, Ping; Shen, Yuanchao; Liu, Tiebing; Li, Guangming; Zeng, Qingdong

    2008-07-01

    Integrated geological and geophysical investigations were carried out in 26 active mines in Northwestern China during the period 2001-2006 to explore for hidden extensions of known ore bodies and to search for new mineralization. This paper presents four case studies from northwest China: the Kuoerzhenkuoa volcanogenic hydrothermal gold deposit, the Nanjinshan breccia-associated gold deposit, the Duolanasayi deposit, associated with a ductile-shear zone, and the Hulu magmatic Cu-Ni sulfide deposit. In these studies, detailed mine-scale geological studies were carried out to determine the location and controls on ore formation. Based on these investigations and a review of previous exploration data, genetic models for the deposits were evaluated, and specific new targets were generated. These target areas were tested with surface geophysical surveys using the Stratagem EH4 system, a hybrid-source magnetotellurics (MT) method. Analysis of the data obtained in the surveys identified geophysical target anomalies that were subsequently drilled. Many of these test holes demonstrate the presence of Au and Cu-Ni mineralization. Evaluation of the geological models was crucial in developing conceptual targets as a basis for surface geophysical surveys. These models established the most likely target areas where Au and Cu-Ni mineralization could occur, but they did not define the limits or the geometries of the mineralized zones. Hybrid MT surveys played an important role in defining the location of buried mineralized systems and in testing the validity of the conceptual targets. The resistivity cross-sections obtained by imaging the MT data established the boundaries and geometries of the host rocks, including the distribution of lithology, structures, alteration, and mineralization. The four case studies in this paper show how this integrated geological and geophysical approach was used successfully to discover hidden mineral deposits.

  11. Synthesis and characterization in AuCu–Si nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Novelo, T.E., E-mail: tenovelo@hotmail.com [Centro de Investigación en Materiales Avanzados, S.C., Laboratorio Nacional de Nanotecnología, Av. Miguel de Cervantes 120, Complejo Industrial Chihuahua, 31109 Chihuahua, Chihuahua Mexico (Mexico); Amézaga-Madrid, P. [Centro de Investigación en Materiales Avanzados, S.C., Laboratorio Nacional de Nanotecnología, Av. Miguel de Cervantes 120, Complejo Industrial Chihuahua, 31109 Chihuahua, Chihuahua Mexico (Mexico); Maldonado, R.D. [Universidad Anáhuac-Mayab, Carretera Mérida-Progreso Km. 15.5 A.P. 96-Cordemex, CP. 97310 Mérida, Yucatán Mexico (Mexico); Oliva, A.I. [Centro de Investigación y de Estudios Avanzados el IPN Unidad Mérida, Departamento de Física Aplicada, Km 6 Antigua Carretera a Progreso, A.P. 73-Cordemex, 97310 Mérida, Yucatán Mexico (Mexico); Alonzo-Medina, G.M. [Universidad Anáhuac-Mayab, Carretera Mérida-Progreso Km. 15.5 A.P. 96-Cordemex, CP. 97310 Mérida, Yucatán Mexico (Mexico)

    2015-03-15

    Au/Cu bilayers with different Au:Cu concentrations (25:75, 50:50 and 75:25 at.%) were deposited on Si(100) substrates by thermal evaporation. The thicknesses of all Au/Cu bilayers were 150 nm. The alloys were prepared by thermal diffusion into a vacuum oven with argon atmosphere at 690 K during 1 h. X-ray diffraction analysis revealed different phases of AuCu and CuSi alloys in the samples after annealing process. CuSi alloys were mainly obtained for 25:75 at.% samples, meanwhile the AuCuII phase dominates for samples prepared with 50:50 at.%. Additionally, the Au:Cu alloys with 75:25 at.%, produce Au{sub 2}Cu{sub 3} and Au{sub 3}Cu phases. The formed alloys were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) to study the morphology and the elemental concentration of the formed alloys. - Highlights: • AuCu/Si alloy thin films were prepared by thermal diffusion. • Alloys prepared with 50 at.% of Au produce the AuCuII phase. • Alloys prepared with 75 at.% of Au produce Au{sub 3}Cu and Au{sub 2}Cu{sub 3} phases. • All alloys present diffusion of Si and Cu through the CuSi alloy formation.

  12. Selectivity of Ni-Cu and Pt-Au alloys in reactions of butanol and related compounds

    Energy Technology Data Exchange (ETDEWEB)

    Van Der Burg, A.; Doornbos, J.; Kos, N.J.; Ultee, W.J.; Ponec, V.

    1978-09-01

    Experiments on the rates and product distributions of the reactions of cyclopentanone, 1-butanol, and 1-butanal with hydrogen on unsupported 0-100% nickel/copper alloys and silica-supported gold, platinum, 14% Pt/Au, and 98% Pt/Au showed that the addition of copper to nickel and gold to platinum had only a small effect on the hydrogenation and dehydrogenation activity of the catalyst but inhibited the intermolecular and intramolecular dehydration of 1-butanol to olefins and ethers. An analysis of these and available data suggested that the dehydration selectivity is controlled by the availability of ensembles of active sites. The surface mechanism is discussed.

  13. YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} matrix-induced in situ growth of plasmonic Au nanoparticles for biological sensor devices

    Energy Technology Data Exchange (ETDEWEB)

    Katzer, C., E-mail: christian.katzer@uni-jena.de; Grosse, V.; Schmidl, F.; Michalowski, P. [Friedrich-Schiller-Universitaet Jena, Institut fuer Festkoerperphysik (Germany); Schmidl, G.; Mueller, R.; Dellith, J.; Schmidt, C.; Jatschka, J.; Fritzsche, W. [Institute of Photonic Technology (IPHT) (Germany)

    2012-12-15

    The authors present a novel method of fabricating crystalline gold nanoparticles used in plasmonic application. The preparation and characterization of monocrystalline Au nanoparticles with diameters between 10 and 100 nm embedded in an YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} matrix is presented as well as a future vision of structured particle arrangements by photolithographic procedures. To use these particles for biological applications, the matrix may has to be dissolved to obtain extracted nanoparticles on a dielectric substrate. Whether the nanoparticles change their position during the extraction process is investigated and the realized dissolving procedure by citric acid solution is shown. The dissolution of the matrix thereby is investigated by X-ray diffraction experiments and energy-dispersive X-ray spectroscopy. Furthermore, the spectral characterization by particle selection is illustrated based on microspectroscopy.

  14. DISLOCATIONS MOBILITY UNDER THE IMAGE FORCE EFFECT IN BICRYSTALS OF CFC MATERIALS: CU-X, X = PB, AL, AU, AG AND NI

    Directory of Open Access Journals (Sweden)

    A OUCHTATI

    2015-06-01

    Full Text Available The image force undergone by a matrix dislocations close and parallel to an interphase boundary is studied in Cu-X bicrystals (with X = Pb, Al, Au, Ag, Ni for disorientations ranging between 0° and 90°.  Dislocations have a Burgers vector  = a/2 [110]. The elastic energy of dislocation-boundary interaction is calculated within the framework of anisotropic linear elasticity. The elastic energy is related to the difference of the two metals shear moduli. It is about a few hundred pico Joule per meter. The image force can be repulsive or attractive according to the sign and the intensity of shear moduli difference. The isoenergy maps have various symmetries according to the disorientation.

  15. Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains

    Energy Technology Data Exchange (ETDEWEB)

    Lagos, M. J. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, R. Sergio B. de Holanda 777, 13083-859 Campinas-SP (Brazil); Laboratório Nacional de Nanotecnologia-LNNANO, 13083-970 Campinas-SP (Brazil); Autreto, P. A. S.; Galvao, D. S., E-mail: galvao@ifi.unicamp.br; Ugarte, D. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, R. Sergio B. de Holanda 777, 13083-859 Campinas-SP (Brazil); Bettini, J. [Laboratório Nacional de Nanotecnologia-LNNANO, 13083-970 Campinas-SP (Brazil); Sato, F.; Dantas, S. O. [Departamento de Física, ICE, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora-MG (Brazil)

    2015-03-07

    We report here an atomistic study of the mechanical deformation of Au{sub x}Cu{sub (1−x)} atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.

  16. CO Oxidation on the Au15Cu15 Cluster and the Role of Vacancies in the MgO(100) Support

    DEFF Research Database (Denmark)

    Ma, Li; Melander, Marko; Weckman, Timo

    2016-01-01

    , the O2 molecule can be effectively activated upon adsorption and dissociated to 2 × O atoms easily, and the reaction modeling takes into account also the reaction paths with adsorbed O atoms. Overall, CO oxidation has lower reaction barriers on the cluster on the F-center. The microkinetic modeling...... on the F-center. The CO2 production rates are much lower for the defect-free and V-center supports which display similar increased activity at elevated temperatures. In all cases, the right combination of CO and O2 partial pressures is instrumental for CO2 production.......A comprehensive theoretical study of a Au15Cu15 cluster on MgO(100) supports and its catalytic activity for CO oxidation has been performed based on the density functional theory and microkinetic modeling. Molecular adsorption and different reaction paths based on the Langmuir−Hinshelwood (LH...

  17. Plavica epithermal Au-Ag-Cu deposit in eastern Macedonia: Geology and 3D model of valuable component distribution in ore

    Science.gov (United States)

    Serafimovski, T.; Volkov, A. V.; Serafimovski, D.; Tasev, G.; Ivanovski, I.; Murashov, K. Yu.

    2017-07-01

    The Plavica Au-Ag-Cu deposit is related to the large Neogene volcanic center, which complicates the paleocaldera in the central Kratovo-Zletovo ore district of eastern Macedonia. Based on the geology, ore mineralogy, wall-rock alteration, and fluid inclusions, the Plavica deposit has been referred to the epithermal high-sulfidation type. The general 3D model of orebody at this deposit is based on its general geological structure and complex distribution of metal contents. The framework of the 3D model, which has been constructed in the ArcGIS System, comprises 195 exploration boreholes 47295.8 m in total length. The 3D model allows to a better understanding of distribution of mineralization and supplements the geological data on the deposit.

  18. Realization and properties of ramp-type YBa2Cu3O7-delta/Au/Nb junctions

    NARCIS (Netherlands)

    Smilde, H.J.H.; Hilgenkamp, Johannes W.M.; Gerritsma, G.J.; Blank, David H.A.; Rogalla, Horst

    2001-01-01

    All-thin-film ramp type Josephson junctions between YBa2Cu3O7−δ and Nb have been fabricated. This procedure allows connections between high-Tc and low-Tc superconductors at different crystal sides of the high-Tc superconductor on one chip, which is of great interest for novel phase devices. A thin

  19. Fluid Inclusion characteristics of syn-late orogenic Co-Ni-Cu-Au deposits in the Siegerland District of the Rhenish Massif, Germany

    Science.gov (United States)

    Wohlgemuth, Christoph; Hellmann, André; Meyer, Franz Michael

    2013-04-01

    The Siegerland District is located in the fold-and-thrust-belt of the Rhenish Massif and hosts various syn- late orogenic vein-hosted hydrothermal mineralization types. Peak-metamorphism and deformation occurred at 312-316 ± 10 Ma (Ahrendt et al., 1978) at pT-conditions of 280 - 320 °C and 0.7 - 1.4 kbar (Hein, 1993). The district is known for synorogenic siderite-quartz mineralization formed during peak-metamorphic conditions. At least 4 syn-late orogenic mineralization types are distinguished: Co-Ni-Cu-Au, Pb-Zn-Cu, Sb-Au and hematite-digenite-bornite mineralization (Hellmann et al., 2012b). Co-Ni-Cu-Au mineralization of the Siegerland District belongs to the recently defined class of metasediment hosted synorogenic Co-Cu-Au deposits (i.e. Slack et al, 2010). Ore minerals are Fe-Co-Ni sulpharsenides, bearing invisible gold, chalcopyrite, and minor As-bearing pyrite. The gangue is quartz. The alteration mineralogy comprises chlorite, illite-muscovite and quartz. The epigenetic quartz veins are closely related to the formation of reverse faults (Hellmann et al., 2011a). Microthermometric studies of fluid inclusions concerning the relationship between mineralization and microstructures have not been done so far for this deposit-class and this will be addressed here. Fluid inclusions are investigated in hydrothermally formed vein-quartz, selected from Co-Ni-Cu-Au mineralization bearing veins showing only minor overprints by later mineralization types. Two quartz generations are distinguished: subhedral quartz-I showing growth zonation and fine grained, recrystallized- and newly formed quartz-II grains forming irregular masses and fracture fillings in quartz-I. Co-Ni-Fe sulpharsenides and chalcopyrite are closely intergrown with quartz-II, implying their contemperaneous formation. However, fluid inclusions in quartz-II are often small, therefore fluid inclusions in quartz-I have been mostly investigated. In total, 180 inclusions from 4 different deposits have been

  20. Extremely Re-Rich Molybdenite from Porphyry Cu-Mo-Au Prospects in Northeastern Greece: Mode of Occurrence, Causes of Enrichment, and Implications for Gold Exploration

    Directory of Open Access Journals (Sweden)

    Tamara Kartal

    2013-05-01

    Full Text Available Extremely Re-rich molybdenite occurs with pyrite in sodic–calcic, sodic–sericitic and sericitic-altered porphyritic stocks of granodioritic–tonalitic and granitic composition in the Sapes–Kirki–Esymi, Melitena and Maronia areas, northeastern Greece. Molybdenite in the Pagoni Rachi and Sapes deposits is spatially associated with rheniite, as well as with intermediate (Mo,ReS2 and (Re,MoS2 phases, with up to 46 wt % Re. Nanodomains and/or microinclusions of rheniite may produce the observed Re enrichment in the intermediate molybdenite–rheniite phases. The extreme Re content in molybdenite and the unique presence of rheniite in porphyry-type mineralization, combined with preliminary geochemical data (Cu/Mo ratio, Au grades may indicate that these deposits have affinities with Cu–Au deposits, and should be considered potential targets for gold mineralization in the porphyry environment. In the post-subduction tectonic regime of northern Greece, the extreme Re and Te enrichments in the magmatic-hydrothermal systems over a large areal extent are attributed to an anomalous source (e.g., chemical inhomogenities in the mantle-wedge triggered magmatism, although local scale processes cannot be underestimated.

  1. High Resolution Vibrational Spectroscopy at the Atomic Scale: CO on Au(110) and Cu(100), and C2H2 on Cu(100)

    Science.gov (United States)

    Xu, Chen; Jiang, Chilun; Zhang, Yanning; Wu, Ruqian; Ho, Wilson

    2012-11-01

    STM-IETS has been regarded as the ultimate tool to identify and characterize single molecules adsorbed on solid surfaces with atomic spatial resolution. With the improvement of the energy resolution obtained at ˜600 mK, STM-IETS is able to reveal subtle interactions between the molecule and its environment which was previously not possible at higher temperatures. Here we demonstrate the capability of sub-Kelvin STM on detecting the influence of the tip as well as the anisotropy of the reconstructed Au(110) surface on the low energy hindered vibrational motions of single adsorbed CO molecule. In the case of acetylene, more vibrational modes are resolved due to the enhanced spectral resolution. Single molecule vibrational spectroscopy with atomic scale spatial resolution opens new possibilities to probe molecular interactions with high spectral resolution.

  2. Study of the A(e,e'$\\pi^+$) Reaction on $^1$H, $^2$H, $^{12}$C, $^{27}$Al, $^{63}$Cu and $^{197}$Au

    Energy Technology Data Exchange (ETDEWEB)

    Qian, X; Clasie, B; Arrington, J; Asaturyan, R; Benmokhtar, F; Boeglin, W; Bosted, P; Bruell, A; Christy, M E; Chudakov, E; Dalton, M M; Daniel, A; Day, D; Dutta, D; El Fassi, L; Ent, R; Fenker, H C; Ferrer, J; Fomin, N; Gao, H; Garrow, K; Gaskell, D; Gray, C; Huber, G M; Jones, M K; Kalantarians, N; Keppel, C E; Kramer, K; Li, Y; Liang, Y; Lung, A F; Malace, S; Markowitz, P; Matsumura, A; Meekins, D G; Mertens, T; Miyoshi, T; Mkrtchyan, H; Monson, R; Navasardyan, T; Niculescu, G; Niculescu, I; Okayasu, Y; Opper, A K; Perdrisat, C; Punjabi, V; Rauf, A W; Rodriquez, V M; Rohe, D; Seely, J; Segbefia, E; Smith, G R; Sumihama, M; Tadevosyan, V; Tang, L; Villano, A; Vulcan, W F; Wesselmann, F R; Wood, S A; Yuan, L; Zheng, X

    2010-05-01

    Cross sections for the p($e,e'\\pi^{+}$)n process on $^1$H, $^2$H, $^{12}$C, $^{27}$Al, $^{63}$Cu and $^{197}$Au targets were measured at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) in order to extract the nuclear transparencies. Data were taken for four-momentum transfers ranging from $Q^2$=1.1 to 4.8 GeV$^2$ for a fixed center of mass energy of $W$=2.14 GeV. The ratio of $\\sigma_L$ and $\\sigma_T$ was extracted from the measured cross sections for $^1$H, $^2$H, $^{12}$C and $^{63}$Cu targets at $Q^2$ = 2.15 and 4.0 GeV$^2$ allowing for additional studies of the reaction mechanism. The experimental setup and the analysis of the data are described in detail including systematic studies needed to obtain the results. The results for the nuclear transparency and the differential cross sections as a function of the pion momentum at the different values of $Q^2$ are presented. Global features of the data are discussed and the data are compared with the results of model calculations for the p($e,e'\\pi^{+}$)n reaction from nuclear targets.

  3. Improving the mechanical performance of Sn57.6Bi0.4Ag solder joints on Au/Ni/Cu pads during aging and electromigration through the addition of tungsten (W) nanoparticle reinforcement

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yi, E-mail: yili64-c@my.cityu.edu.hk [Department of Electronic Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Luo, Kaiming; Lim, Adeline B.Y.; Chen, Zhong [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Wu, Fengshun [School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan (China); Chan, Y.C. [Department of Electronic Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2016-07-04

    Sn57.6Bi0.4Ag solder has been reinforced successfully through the addition of tungsten (W) nanoparticles at a concentration of 0.5 wt%. With the addition of W nanoparticles, the solder matrix lamellar interphase spacing was reduced by 31.0%. Due to the dispersion of W nanoparticles and the consequently refined microstructure, the mechanical properties of the solder alloy were enhanced, as indicated by a 6.2% improvement in the microhardness. During the reflow of solder on Au/Ni/Cu pads, the entire Au layer dissolved into the molten solder rapidly and a large number of (Au,Ni)(Sn,Bi){sub 4} particles were formed. The fracture path of the as-reflowed joint was within the solder region, showing ductile characteristic, and the shear strength was reinforced by 8.2%, due to the enhanced mechanical properties of the solder. During the subsequent aging process, the Au migrated back towards the interface and a thick layer of interfacial (Au,Ni)(Sn,Bi){sub 4} IMC was formed, leading to the shift of the fracture path to the interfacial IMC region, the transformation to brittle fracture and the deterioration of the strength of the joint, due to Au embrittlement. By adding W nanoparticles, the migration of Au was mitigated and the thickness of the (Au,Ni)(Sn,Bi){sub 4} layer was reduced significantly, which reduced the Au embrittlement-induced deterioration of the strength of the joint. During electromigration, the segregation of the Bi-rich and Sn-rich phases and the accumulation of the (Au,Ni)(Sn,Bi){sub 4} layer at cathode interface were mitigated by the addition of W nanoparticles, which improved the electromigration resistance.

  4. Le CRDI au Brésil

    International Development Research Centre (IDRC) Digital Library (Canada)

    IA. LE. La recherche a pour but de faire en sorte que la croissance économique donne lieu à la création de meilleurs emplois. Les noms et les frontières indiqués sur la carte n'impliquent ni reconnaissance ni acceptation officielle de la part du CRDI. BRÉSIL. Macapá. Manaus. São Paulo. Belém. Fortaleza. Recife. Salvador.

  5. Origin and evolution of mineralizing fluids and exploration of the Cerro Quema Au-Cu deposit (Azuero Peninsula, Panama) from a fluid inclusion and stable isotope perspective

    Science.gov (United States)

    Corral, Isaac; Cardellach, Esteve; Corbella, Merce; Canals, Angels; Griera, Albert; Gomez-Gras, David; Johnson, Craig A.

    2017-01-01

    Cerro Quema is a high sulfidation epithermal Au-Cu deposit with a measured, indicated and inferred resource of 35.98 Mt. @ 0.77 g/t Au containing 893,600 oz. Au (including 183,930 oz. Au equiv. of Cu ore). It is characterized by a large hydrothermal alteration zone which is interpreted to represent the lithocap of a porphyry system. The innermost zone of the lithocap is constituted by vuggy quartz with advanced argillic alteration locally developed on its margin, enclosed by a well-developed zone of argillic alteration, grading to an external halo of propylitic alteration. The mineralization occurs in the form of disseminations and microveinlets of pyrite, chalcopyrite, enargite, tennantite, and trace sphalerite, crosscut by quartz, barite, pyrite, chalcopyrite, sphalerite and galena veins.Microthermometric analyses of two phase (L + V) secondary fluid inclusions in igneous quartz phenocrysts in vuggy quartz and advanced argillically altered samples indicate low temperature (140–216 °C) and low salinity (0.5–4.8 wt% NaCl eq.) fluids, with hotter and more saline fluids identified in the east half of the deposit (Cerro Quema area).Stable isotope analyses (S, O, H) were performed on mineralization and alteration minerals, including pyrite, chalcopyrite, enargite, alunite, barite, kaolinite, dickite and vuggy quartz. The range of δ34S of sulfides is from − 4.8 to − 12.7‰, whereas δ34S of sulfates range from 14.1 to 17.4‰. The estimated δ34SΣS of the hydrothermal fluid is − 0.5‰. Within the advanced argillic altered zone the δ34S values of sulfides and sulfates are interpreted to reflect isotopic equilibrium at temperatures of ~ 240 °C. The δ18O values of vuggy quartz range from 9.0 to 17.5‰, and the δ18O values estimated for the vuggy quartz-forming fluid range from − 2.3 to 3.0‰, indicating that it precipitated from mixing of magmatic fluids with surficial fluids. The δ18O of kaolinite ranges from 12.7 to 18.1‰ and

  6. Formation of a paleothermal anomaly and disseminated gold deposits associated with the Bingham Canyon porphyry Cu-Au-Mo system, Utah

    Science.gov (United States)

    Cunningham, C.G.; Austin, G.W.; Naeser, C.W.; Rye, R.O.; Ballantyne, G.H.; Stamm, R.G.; Barker, C.E.

    2004-01-01

    The thermal history of the Oquirrh Mountains, Utah, indicates that hydrothermal fluids associated with emplacement of the 37 Ma Bingham Canyon porphyry Cu-Au-Mo deposit extended at least 10 km north of the Bingham pit. An associated paleothermal anomaly enclosed the Barneys Canyon and Melco disseminated gold deposits and several smaller gold deposits between them. Previous studies have shown the Barneys Canyon deposit is near the outer limit of an irregular distal Au-As geochemical halo, about 3 km beyond an intermediate Pb-Zn halo, and 7 km beyond a proximal pyrite halo centered on the Bingham porphyry copper deposit. The Melco deposit also lies near the outer limit of the Au-As halo. Analysis of several geothermometers from samples collected tip to 22 km north of the Bingham Canyon porphyry Cu-Au-Mo deposit indicate that most sedimentary rocks of the Oquirrh Mountains, including those at the gold deposits, have not been regionally heated beyond the "oil window" (less than about 150??C). For geologically reasonable heating durations, the maximum sustained temperature at Melco, 6 km north of the Bingham pit, and at Barneys Canyon, 7.5 km north of the pit, was between 100??C and 140??C, as indicated by combinations of conodont color alteration indices of 1.5 to 2, mean random solid bitumen reflectance of about 1.0 percent, lack of annealing of zircon fission tracks, and partial to complete annealing of apatite fission tracks. The pattern of reset apatite fission-track ages indicates that the gold deposits are located approximately on the 120??C isotherm of the 37 Ma paleothermal anomaly assuming a heating duration of about 106 years. The conodont data further constrain the duration of heating to between 5 ?? 104 and 106 years at approximately 120??C. The ??18O of quartzite host rocks generally increases from about 12.6 per mil at the porphyry to about 15.8 per mil approximately 11 km from the Bingham deposit. This change reflects interaction of interstitial clays in

  7. Les usages des technologies de l’information et de la communication dans l’administration judiciaire au Brésil Uses of Information and Communication Technologies in the Brazilian Judicial Administration

    Directory of Open Access Journals (Sweden)

    Alexandre Veronese

    2011-10-01

    Full Text Available Cet article repose sur le postulat selon lequel il faut définitivement abandonner l’idée de neutralité des technologies d’information et de communication et considérer celles-ci non comme des vecteurs et facteurs de transformation systématique des pratiques mais plutôt comme des dispositifs dont le développement repose sur les appropriations et usages sociaux (notamment ceux des utilisateurs qui en sont faits. Dans un premier temps, afin d’aider à la compréhension du phénomène d’informatisation au Brésil, l’article dresse une synthèse du débat portant sur la gouvernance de l’Internet. Puis il propose une discussion théorique à la suite de laquelle il montre la diffusion de l’usage de l’informatique dans les différentes composantes du système judiciaire brésilien entre 2004 et 2010. Enfin, après avoir constaté le développement du recours aux technologies informatiques dans les juridictions, les auteurs ouvrent une réflexion sur les critères et les modalités d’évaluation de l’intégration des systèmes informatiques dans le travail quotidien de la magistrature.The present paper begins with a report of the key questions on the debate about e-government in order to support the understanding of the phenomenon of informatization of the Brazilian courts. The central theme of the paper relies on the conclusion that it is the social use which determines the insertion of the technology in the daily life and not the other way around. In this way, the application of information and communication technologies is not merely marked by the neutral use of new working tools. Therefore, the way in which its social integration occurs will determine whether the consequences of its use will be beneficial or not. Following a theoretical review, the expansion on the period between 2004 and 2010, which clarifies the practical importance of the informatization to the participants of the Brazilian judicial system, is described

  8. van der Waals-corrected Density Functional Theory simulation of adsorption processes on noble-metal surfaces: Xe on Ag(111), Au(111), and Cu(111)

    CERN Document Server

    Silvestrelli, Pier Luigi

    2016-01-01

    The DFT/vdW-WF2s1 method based on the generation of localized Wannier functions, recently developed to include the van der Waals interactions in the Density Functional Theory and describe adsorption processes on metal surfaces by taking metal-screening effects into account, is applied to the case of the interaction of Xe with noble-metal surfaces, namely Ag(111), Au(111), and Cu(111). The study is also repeated by adopting the DFT/vdW-QHO-WF variant relying on the Quantum Harmonic Oscillator model which describes well many-body effects. Comparison of the computed equilibrium binding energies and distances, and the $C_3$ coefficients characterizing the adatom-surface van der Waals interactions, with available experimental and theoretical reference data shows that the methods perform well and elucidate the importance of properly including screening effects. The results are also compared with those obtained by other vdW-corrected DFT schemes, including PBE-D, vdW-DF, vdW-DF2, rVV10, and by the simpler Local Dens...

  9. Les territoires de l´agrobusiness au Brésil Os territórios do agronegócio no Brasil The territories of agrobusiness in Brazil

    Directory of Open Access Journals (Sweden)

    Denise Elias

    2012-06-01

    Full Text Available Les transformations qui se sont produites dans l’activité agricole brésilienne lors de ces quatre dernières décennies, ont eu un impact profond sur la réorganisation du territoire brésilien, donnant lieu à de nouveaux arrangements territoriaux. L’objectif principal de ce texte est de soumettre au débat quelques aspects sur les nouvelles formes d’utilisation et d’organisation du territoire brésilien à partir des processus de diffusion de l’agrobusiness mondialisé. Dans la thèse défendue, on montre qu’au Brésil une partie significative des transformations à la campagne, dans les cinq dernières décennies, est due à la restructuration productive de l’agropastoral - comprise comme une exacerbation du mode capitaliste de produire dans le secteur - et à l’organisation des réseaux agroindustriels, des promoteurs de transformations dans les éléments techniques et sociaux de la structure agraire. En quelques décennies, le pays passe d’un pays éminemment agraire à une des dix économies mondiale. Les réflexes dans la production, dans la société et dans l’espace sont nombreux et complexes. De cette manière, les facteurs de localisation classiques sont redimensionnés, donnant de nouvelles possibilités à la production et, par conséquent, une vraie dispersion spatiale de la production et une réorganisation du territoire. Parmi les principaux vecteurs de cette réorganisation nous aurions la diffusion de l’agrobusiness mondialisé. Tout ceci engendre un attisement de la division territoriale du travail ; une nouvelle distribution des fonctions productives ; une nouvelle géographique économique qui culminent dans un remodelage du territoire et dans de nouveaux découpages spatiaux pour les études géographique. Un de ces découpages spatiaux est totalement pertinent pour analyser l’émergence de nouveaux arrangements territoriaux productifs résultant des dynamiques socio-spatiales inhérentes à la

  10. Mineralization and geophysical exploration by IP/RS and ground magnetic survey in MA-I and surrounding area, Maherabad porphyry Cu-Au prospect area, east of Iran

    Directory of Open Access Journals (Sweden)

    Azadeh Malekzadeh Shafaroudi

    2009-10-01

    Full Text Available Maherabad prospect area, which is studied in detail, is the first porphyry Cu-Au mineralization in the east of Iran. Based on relation of mineralization with subvolcanic intrusive bodies mostly monzonitic with porphyry texture, extent and types of alteration including potassic, sericitic- potassic, quartz- sericite- carbonate- pyrite, quartz- carbonate- pyrite, silicification- propylitic, propylitic, stockwork mineralization, assemblages hypogene mineralization including pyrite, chalcopyrite, bornite and magnetite and high anomalies of Cu and Au, Mineralization is porphyry Cu-Au-type. MA-I area, which is covered by regolith from its surrounding is the most important section of mineralization in the region because of intensive of quartz-sericite-carbonate-pyrite alteration and very high dense quartz-sulfide veinlets. IP/RS and ground magnetic surveys were conducted in the MA-I prospect area and its surrounding plain. Drilling on the IP suede section anomaly resulted to the recognition of sulfide mineralization in on extensive area under the regolith. Surface and underground detailed studies of geology, alteration, mineralization and geochemistry confirm the extension of covered mineralization to the south and west of the area. Based on the ground magnetic anomaly, the center of mineralization system, potassic zone, to the southwest of the area was recognized. Quartz0sericite-carbonate-pyrite alteration zone, which is located around the potassic zone, has very low magnetic response. IP/RS and ground magnetic surveys in a broader area than before are strongly recommended.

  11. Rare Earth Element Fluorocarbonate Minerals from the Olympic Dam Cu-U-Au-Ag Deposit, South Australia

    Directory of Open Access Journals (Sweden)

    Danielle S. Schmandt

    2017-10-01

    Full Text Available Olympic Dam is a world-class breccia-hosted iron-oxide copper-gold-uranium ore deposit located in the Gawler Craton, South Australia. It contains elevated concentrations of rare earth elements (REE which occur as the REE minerals bastnäsite, synchysite, florencite, monazite, and xenotime. This is the first study to focus on the mineralogy and composition of the most abundant REE mineral at Olympic Dam, bastnäsite, and subordinate synchysite. The sample suite extends across the deposit and represents different sulfide mineralization styles (chalcopyrite-bornite and bornite-chalcocite and breccias of various types, ranging from those dominated by clasts of granite, dykes, and hematite. The REE-fluorocarbonates (bastnäsite and synchysite typically occur as fine-grained (<50 μm disseminations in Cu-Fe-sulfides and gangue minerals, and also within breccia matrix. They are also locally concentrated within macroscopic REE-mineral-rich pockets at various locations across the deposit. Such coarse-grained samples formed the primary target of this study. Three general textural groups of bastnäsite are recognized: matrix (further divided into disseminated, fine-grained, and stubby types, irregular (sulfide-associated, and clast replacement. Textures are largely driven by the specific location and prevailing mineral assemblage, with morphology and grain size often controlled by the associated minerals (hematite, sulfides. Major element concentration data reveal limited compositional variation among the REE-fluorocarbonates; all are Ce-dominant. Subtle compositional differences among REE-fluorocarbonates define a spectrum from relatively La-enriched to (Ce + Nd-enriched phases. Granite-derived hydrothermal fluids were the likely source of F in the REE-fluorocarbonates, as well as some of the CO2, which may also have been contributed by associated mafic-ultramafic magmatism. However, transport of REE by Cl-ligands is the most likely scenario. Stubby bastn

  12. Magnetic ordering induced by interladder coupling in the spin-1/2 Heisenberg two-leg ladder antiferromagnet C9H18N2CuBr4

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Tao [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Schmidt, K. P. [Technische Universitat Dortmund, Dortmund (Germany); Coester, K. [Technische Universitat Dortmund, Dortmund (Germany); Awwadi, F. F. [The University of Jordan, Amman (Jordan); Turnbull, M. M. [Clark Univ., Worcester, MA (United States); Qiu, Y. [National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States); Univ. of Maryland, College Park, MD (United States); Rodriguez-Rivera, J. A. [National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States); Univ. of Maryland, College Park, MD (United States); Zhu, M. [Michigan State Univ., East Lansing, MI (United States); Ke, X. [Michigan State Univ., East Lansing, MI (United States); Aoyama, C. P. [Univ. of Florida, Gainesville, FL (United States); Takano, Y. [Univ. of Florida, Gainesville, FL (United States); Cao, Huibo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tian, Wei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ma, Jie [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Custelcean, Radu [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zhou, H. D. [Univ. of Tennessee, Knoxville, TN (United States); Matsuda, Masaaki [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-05-30

    In this article, we present specific-heat and neutron-scattering results for the S=1/2 quantum antiferromagnet (dimethylammonium)(3,5-dimethylpyridinium)CuBr4. The material orders magnetically at TN=1.99(2) K, and magnetic excitations are accompanied by an energy gap of 0.30(2) meV due to spin anisotropy. The system is best described as coupled two-leg spin-1/2 ladders with the leg exchange Jleg=0.60(2) meV, rung exchange Jrung=0.64(9) meV, interladder exchange Jint=0.19(2) meV, and an interaction-anisotropy parameter λ=0.93(2), according to inelastic neutron-scattering measurements. In contrast to most spin ladders reported to date, the material is a rare example in which the interladder coupling is very near the critical value required to drive the system to a Néel-ordered phase without the assistance of a magnetic field.

  13. CuO-induced signal amplification strategy for multiplexed photoelectrochemical immunosensing using CdS sensitized ZnO nanotubes arrays as photoactive material and AuPd alloy nanoparticles as electron sink.

    Science.gov (United States)

    Sun, Guoqiang; Zhang, Yan; Kong, Qingkun; Zheng, Xiaoxiao; Yu, Jinghua; Song, Xianrang

    2015-04-15

    In this work, multiplexed photoelectrochemical (PEC) immunoassays are introduced into an indium tin oxide (ITO) device. Firstly, the ITO device is fabricated using a simple acid etch treatment method. Secondly, AuPd alloy nanoparticles are electro-deposited on ITO working electrodes as electron sink to construct the immunosensor platform. After that, ZnO nanotubes (ZNTs) arrays are synthesized via chemical etching of ZnO nanorods that are grown on AuPd surface by electrochemical deposition method. Subsequently, CdS is electro-deposited on ZNTs arrays and used as photoactive material. Then, CuO nanoseeds are labeled with signal antibodies and firstly used as PEC signal amplification label. The introduction of CuO brings signal amplification because of the conduction band (CB) of both CuO and ZnO are lower than that of CdS, CuO will compete the photo-induced electrons in CB of CdS with ZnO, leading to the decrease of the photocurrent intensity. Using cancer antigen 125, prostate specific antigen and α-fetoprotein as model analytes, the proposed immunoassay exhibits excellent precision and sensitivity. Meanwhile, this work provides a promising, addressable and simple strategy for the multi-detection of tumor markers. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Involvement of magmatic fluids at the Laloki and Federal Flag massive sulfide Cu-Zn-Au-Ag deposits, Astrolabe mineral district, Papua New Guinea: sulfur isotope evidence

    Science.gov (United States)

    Noku, Shadrach K.; Espi, Joseph O.; Matsueda, Hiroharu

    2015-01-01

    We present the first sulfur (S) isotope data of sulfides, sulfates, pyrite in host mudstone, and bulk sulfur of gabbroic rocks from the Laloki and Federal Flag massive Cu-Zn-Au-Ag deposits in the Astrolabe mineral district, Papua New Guinea. Early-stage pyrite-marcasite, chalcopyrite, and sphalerite from Laloki display wide range of δ34S values from -4.5 to +7.0 ‰ ( n = 16). Late-stage pyrite, chalcopyrite, and sphalerite have restricted δ34S values of -1.9 to +4.7 ‰ ( n = 16). The mineralizing stage these correspond to had moderately saline (5.9-8.4 NaCl eq. wt%) mineralizing fluids of possible magmatic origin. A single analysis of late-stage barite has a value of δ34S +17.9 ‰, which is likely similar to coexisting seawater sulfate. Pyrite from the foot-wall mudstone at Laloki has very light δ34S values of -36.1 to -33.8 ‰ ( n = 2), which suggest an organic source for S. Pyrite-marcasite and chalcopyrite from Federal Flag show δ34S values of -2.4 to -1.9 ‰ ( n = 2), consistent with a magmatic origin, either leached from intrusive magmatic rocks or derived from magmatic-hydrothermal fluids. The very narrow range and near-zero δ34S values (-1.0 to +0.6 ‰) of bulk gabbroic samples is consistent with mantle-derived magmatic S. Sulfur isotope characteristics of sulfides and sulfates are, however, very similar to base metal sulfide accumulations associated with modern volcanic arcs and sedimented mid-ocean ridges. The most reasonable interpretation is that the range of the sulfide and sulfate δ34S values from both Laloki and Federal Flag massive sulfide deposits is indicative of the complex interaction of magmatic fluids, seawater, gabbroic rocks, and mudstone.

  15. Integrating Data of ASTER and Landsat-8 OLI (AO for Hydrothermal Alteration Mineral Mapping in Duolong Porphyry Cu-Au Deposit, Tibetan Plateau, China

    Directory of Open Access Journals (Sweden)

    Tingbin Zhang

    2016-10-01

    Full Text Available One of the most important characteristics of porphyry copper deposits (PCDs is the type and distribution pattern of alteration zones which can be used for screening and recognizing these deposits. Hydrothermal alteration minerals with diagnostic spectral absorption properties in the visible and near-infrared (VNIR through the shortwave infrared (SWIR regions can be identified by multispectral and hyperspectral remote sensing data. Six Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER bands in SWIR have been shown to be effective in the mapping of Al-OH, Fe-OH, Mg-OH group minerals. The five VNIR bands of Landsat-8 (L8 Operational Land Imager (OLI are useful for discriminating ferric iron alteration minerals. In the absence of complete hyperspectral coverage area, an opportunity, however, exists to integrate ASTER and L8-OLI (AO to compensate each other’s shortcomings in covering area for mineral mapping. This study examines the potential of AO data in mineral mapping in an arid area of the Duolong porphyry Cu-Au deposit(Tibetan Plateau in China by using spectral analysis techniques. Results show the following conclusions: (1 Combination of ASTER and L8-OLI data (AO has more mineral information content than either alone; (2 The Duolong PCD alteration zones of phyllic, argillic and propylitic zones are mapped using ASTER SWIR bands and the iron-bearing mineral information is best mapped using AO VNIR bands; (3 The multispectral integration data of AO can provide a compensatory data of ASTER VNIR bands for iron-bearing mineral mapping in the arid and semi-arid areas.

  16. The age of Au-Cu-Pb-bearing veins in the poly-orogenic Ubendian Belt (Tanzania): U-Th-total Pb dating of hydrothermally altered monazite

    Science.gov (United States)

    Kazimoto, Emmanuel Owden; Schenk, Volker; Appel, Peter

    2015-01-01

    The age of gold-copper-lead mineralization in the Katuma Block of the Ubendian Belt remains controversial because of the lack of radiometric ages that correlate with the age of tectonothermal events of this poly-orogenic belt. Previous studies reported whole rock and mineral Pb-Pb ages ranging between 1,660 and 720 Ma. In this study, we report U-Th-total Pb ages of monazite from hydrothermally altered metapelites that host the Au-Cu-Pb-bearing veins. Three types of chemically and texturally distinct types of monazite grains or zones of grains were identified: monazite cores, which yielded a metamorphic age of 1,938 ± 11 Ma ( n = 40), corresponding to known ages of a regional metamorphic event, deformation and granitic plutonism in the belt; metamorphic overgrowths that date a subsequent metamorphic event at 1,827 ± 10 Ma ( n = 44) that postdates known eclogite metamorphism (at ca. 1,880 Ma) in the belt; hydrothermally altered poikilitic monazite, formed by dissolution-precipitation processes, representing the third type of monazite, constrain the age of a hydrothermal alteration event at 1,171 ± 17 Ma ( n = 19). This Mesoproterozoic age of the hydrothermal alteration coincides with the first amphibolite grade metamorphism of metasediments in the Wakole Block, which adjoins with a tectonic contact the vein-bearing Katuma Block to the southwest. The obtained distinct monazite ages not only constrain the ages of metamorphic events in the Ubendian Belt, but also provide a link between the metamorphism of the Wakole metasediments and the generation of the hydrothermal fluids responsible for the formation of the gold-copper-lead veins in the Katuma Block.

  17. Pb-Sr-Nd isotopes in surficial materials at the Pebble Porphyry Cu-Au-Mo Deposit, Southwestern Alaska: can the mineralizing fingerprint be detected through cover?

    Science.gov (United States)

    Ayuso, Robert A.; Kelley, Karen D.; Eppinger, Robert G.; Forni, Francesca

    2013-01-01

    The Cretaceous Pebble porphyry Cu-Au-Mo deposit is covered by tundra and glacigenic sediments. Pb-Sr-Nd measurements were done on sediments and soils to establish baseline conditions prior to the onset of mining operations and contribute to the development of exploration methods for concealed base metal deposits of this type. Pebble rocks have a moderate range for 206Pb/204Pb = 18.574 to 18.874, 207Pb/204Pb = 15.484 to 15.526, and 208,Pb/204Pb = 38.053 to 38.266. Mineralized granodiorite shows a modest spread in 87Sr/86Sr (0.704354–0.707621) and 143Nd/144Nd (0.512639–0.512750). Age-corrected (89 Ma) values for the granodiorite yield relatively unradiogenic Pb (e.g., 207Pb/204Pb 87Sr/86Sr, and positive values of ɛNd (1.00–4.52) that attest to a major contribution of mantle-derived source rocks. Pond sediments and soils have similar Pb isotope signatures and 87Sr/86Sr and 143Nd/144Nd values that resemble the mineralized granodiorites. Glacial events have obscured the recognition of isotope signatures of mineralized rocks in the sediments and soils. Baseline radiogenic isotope compositions, prior to the onset of mining operations, reflect natural erosion, transport and deposition of heterogeneous till sheets that included debris from barren rocks, mineralized granodiorite and sulfides from the Pebble deposit, and other country rocks that pre- and postdate the mineralization events. Isotopic variations suggest that natural weathering of the deposit is generally reflected in these surficial materials. The isotope data provide geochemical constraints to glimpse through the extensive cover and together with other geochemical observations provide a vector to concealed mineralized rocks genetically linked with the Pebble deposit.

  18. Geological analysis of aeromagnetic data from southwestern Alaska: implications for exploration in the area of the Pebble porphyry Cu-Au-Mo deposit

    Science.gov (United States)

    Anderson, Eric D.; Hitzman, Murray W.; Monecke, Thomas; Bedrosian, Paul A.; Shah, Anjana K.; Kelley, Karen D.

    2013-01-01

    Aeromagnetic data are used to better understand the geology and mineral resources near the Late Cretaceous Pebble porphyry Cu-Au-Mo deposit in southwestern Alaska. The reduced-to-pole (RTP) transformation of regional-scale aeromagnetic data shows that the Pebble deposit is within a cluster of magnetic anomaly highs. Similar to Pebble, the Iliamna, Kijik, and Neacola porphyry copper occurrences are in magnetic highs that trend northeast along the crustal-scale Lake Clark fault. A high-amplitude, short- to moderate-wavelength anomaly is centered over the Kemuk occurrence, an Alaska-type ultramafic complex. Similar anomalies are found west and north of Kemuk. A moderate-amplitude, moderate-wavelength magnetic low surrounded by a moderate-amplitude, short-wavelength magnetic high is associated with the gold-bearing Shotgun intrusive complex. The RTP transformation of the district-scale aeromagnetic data acquired over Pebble permits differentiation of a variety of Jurassic to Tertiary magmatic rock suites. Jurassic-Cretaceous basalt and gabbro units and Late Cretaceous biotite pyroxenite and granodiorite rocks produce magnetic highs. Tertiary basalt units also produce magnetic highs, but appear to be volumetrically minor. Eocene monzonite units have associated magnetic lows. The RTP data do not suggest a magnetite-rich hydrothermal system at the Pebble deposit. The 10-km upward continuation transformation of the regional-scale data shows a linear northeast trend of magnetic anomaly highs. These anomalies are spatially correlated with Late Cretaceous igneous rocks and in the Pebble district are centered over the granodiorite rocks genetically related to porphyry copper systems. The spacing of these anomalies is similar to patterns shown by the numerous porphyry copper deposits in northern Chile. These anomalies are interpreted to reflect a Late Cretaceous magmatic arc that is favorable for additional discoveries of Late Cretaceous porphyry copper systems in southwestern

  19. Surface acidity scales: Experimental measurements of Brønsted acidities on anatase TiO2 and comparison with coinage metal surfaces

    Science.gov (United States)

    Silbaugh, Trent L.; Boaventura, Jaime S.; Barteau, Mark A.

    2016-08-01

    The first quantitative surface acidity scale for Brønsted acids on a solid surface is presented through the use of titration-displacement and equilibrium experiments on anatase TiO2. Surface acidities of species on TiO2 correlated with gas phase acidities, as was previously observed in qualitative studies of Brønsted acid displacement on Ag(110), Cu(110) and Au(111). A 90% compression of the surface acidity scale relative to the gas phase was observed due to compensation from the covalent component of the conjugate base - surface bond. Adsorbed conjugate bases need not be completely anionic for correlations with gas phase acidities to hold. Positive and negative substituent effects, such as substituted fluorine and hydrocarbon sidechain dispersion interactions with the surface, may modify the surface acidity scale, in agreement with previous experimental and theoretical work on Au(111).

  20. Study of Dielectric Behavior and Charge Conduction Mechanism of Poly(Vinyl Alcohol) (PVA)-Copper (Cu) and Gold (Au) Nanocomposites as a Bio-resorbable Material for Organic Electronics

    Science.gov (United States)

    Mahendia, Suman; Goyal, Parveen Kumar; Tomar, Anil Kumar; Chahal, Rishi Pal; Kumar, Shyam

    2016-10-01

    Poly(vinyl alcohol) (PVA) embedded with varying concentrations of chemically synthesized copper (Cu) and gold (Au) nanoparticles (NPs) were prepared using ex situ sol-gel casting method. The addition of almost the same concentration of CuNPs in PVA improves the conducting properties, while that of AuNPs improves the dielectric nature of composite films. It has been found that addition of AuNPs up to ˜0.4 wt.% concentration enhaneces the capacitive nature due to the formation of small Coulomb tunneling knots as internal capacitors. The dielectric studies suggest the Maxwell-Wagner interfacial polarization as the dominant dielectric relaxation process, whereas the I- V characteristics indicate bulk limited Poole-Frenkel emission at high voltages as the dominant charge transport mechanism operating at room temperature in all specimens. These novel features lead to the conclusion that addition of a small quantity of metal nanoparticles can help tune the properties of PVA for desired applications in bio-compatible polymer-based organic electronic devices.

  1. AVALIAÇÃO DA QUALIDADE DO AR NA ÁREA URBANA DE FREDERICO WESTPHALEN, RS, ATRAVÉS DA DETERMINAÇÃO DE Sr, Zr, Br, Cu E Zn EM AMOSTRAS DE LIQUENS

    Directory of Open Access Journals (Sweden)

    Mariele Fioreze

    2014-05-01

    Full Text Available A utilização de organismos vivos como indicadores da qualidade do ar atmosférico é uma alternativa que vem crescendo e ganhando destaque em diversos trabalhos pelo mundo. Dentre os organismos mais utilizados, estão os liquens, que se destacam pela alta capacidade de acumulação de elementos metálicos e do íon sulfato, gerando respostas significativas quando expostos a ambientes sob influência de agentes contaminantes. O objetivo deste trabalho foi avaliar a qualidade do ar atmosférico da cidade de Frederico Westphalen, RS, através da determinação de Sr, Zr, Br, Cu e Zn em amostras de liquens do gênero Parmotrema. Para tanto, foram comparadas as concentrações das espécies em estudo presentes em liquens que naturalmente se desenvolveram no perímetro urbano do município com as concentrações encontradas em amostras de liquens retiradas de área rural preservada da ação de poluentes urbanos. O uso do gênero Parmotrema como bioindicador da qualidade do ar atmosférico permitiu visualizar o aumento dos níveis de acumulação dos elementos em estudo em liquens da área urbana do município, o que comprova a existência de fontes de poluição que influenciam na qualidade do ar atmosférico nesse local.

  2. In situ major and trace element analysis of amphiboles in quartz monzodiorite porphyry from the Tonglvshan Cu-Fe (Au) deposit, Hubei Province, China: insights into magma evolution and related mineralization

    Science.gov (United States)

    Duan, Deng-Fei; Jiang, Shao-Yong

    2017-05-01

    The Tonglvshan deposit is the largest Cu-Fe (Au) skarn deposit in the Edong district, which is located in the westernmost part of the Middle and Lower Yangtze River metallogenic belt, China. In this study, we performed a detailed in situ analysis of major and trace elements in amphiboles from the ore-related Tonglvshan quartz monzodiorite porphyry using electron microprobe (EMPA) analysis and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Two distinct populations of amphiboles, which can be distinguished by their aluminum content, are found in the quartz monzodiorite porphyry. The low-aluminum (Low-Al) amphiboles are subhedral or anhedral and formed at 46.3-73.5 MPa and 713-763 °C. In contrast, the high-aluminum (High-Al) amphiboles are euhedral and formed at 88-165 MPa and 778-854 °C. Some euhedral amphiboles are partially or completely replaced by Low-Al amphibole. The compositions of parental melts in equilibrium with the High-Al amphibole ( Melt 1) and Low-Al amphibole ( Melt 2) were computed by applying solid/liquid partition coefficients. This modeling shows that magma in equilibrium with High-Al amphibole ( Melt 1) underwent 40% fractional crystallization of amphibole, plagioclase and apatite at a depth of 5 km to evolve to magma in equilibrium with Low-Al amphibole ( Melt 2). Copper enrichment occurred in the magma after undergoing fractional crystallization. The magma had a high oxygen fugacity, increasing from NNO + 1 ( Melt 1) through NNO + 2 to HM ( Melt 2), which could have prevented the loss of Cu (and possibly Au) to sulfide minerals during crystallization. Finally, the evolved magma intruded to shallower depths, where it presumably exsolved aqueous ore-forming fluids. Therefore, the large Cu-Fe-Au reserves of the Tonglvshan deposit can likely be attributed to a combination of controlling factors, including high oxygen fugacity, fractional crystallization, fluid exsolution, and a shallow emplacement depth.

  3. Measurement of cross sections for alpha-induced reactions on 197Au and thick-target yields for the ((alpha),(gamma)) process on 64Zn and 63Cu

    Energy Technology Data Exchange (ETDEWEB)

    Basunia, M S; Shugart, H A; Smith, A R; Norman, E B

    2006-08-14

    We have measured the cross sections for the {sup 197}Au({alpha},{gamma}){sup 201}Tl and {sup 197}Au({alpha},2n){sup 199}Tl reactions in the 17.9- to 23.9-MeV energy range, and {sup 197}Au({alpha},n){sup 200}Tl reaction in the 13.4- to 23.9-MeV energy range using an activation technique. Thick-target yields for the {sup 64}Zn({alpha},{gamma}){sup 68}Ge (7- to 14-MeV) and {sup 63}Cu({alpha},{gamma}){sup 67}Ga (7-MeV) reactions were measured. For all measurements, natural elements were bombarded with He{sup +} beams from the 88'' Cyclotron at the Lawrence Berkeley National Laboratory (LBNL). Irradiated samples were counted using a g-spectrometry system at LBNL's Low Background Facility. Measured {sup 197}Au({alpha},{gamma}){sup 201}Tl cross-sections were compared with the NON-SMOKER theoretical values. The thick-target yields for the {sup 64}Zn({alpha},{gamma}){sup 68}Ge and {sup 63}Cu({alpha},{gamma}){sup 67}Ga reactions are also compared with the theoretical yield, calculated numerically using the energy dependent NON-SMOKER cross section data. In both cases, measured values are found to follow a trend of overlapping the predicted value near the alpha nucleus barrier height and fall below with a slowly widening difference between them in the sub barrier energy points.

  4. Poly (vinyl alcohol)/gum karaya electrospun plasma treated membrane for the removal of nanoparticles (Au, Ag, Pt, CuO and Fe{sub 3}O{sub 4}) from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Padil, Vinod Vellora Thekkae; Černík, Miroslav, E-mail: miroslav.cernik@tul.cz

    2015-04-28

    In the present work, nanofibre membranes composed of polyvinyl alcohol (PVA) and a natural gum karaya (GK) hydrocolloid were prepared using electrospinning. The electrospun membranes of PVA/GK were cross-linked with heat treatment and later methane plasma was used to obtain a hydrophobic membrane. The morphology, characterization and adsorption ability of P-NFM was assessed using scanning electron microscopy, UV–vis spectroscopy, ATR-FTIR techniques, water contact angle and ICP-MS analytical methods. The membrane was employed for the extraction of nanoparticles (Ag, Au, Pt, CuO and Fe{sub 3}O{sub 4}) from water. The nanoparticle extraction kinetic and adsorption isotherm perform the pseudo-second-order model and Langmuir isotherm model, respectively. The adsorption capacities of the membrane for the removal of NPs from water diverge in the order Pt > Au > Ag > CuO > Fe{sub 3}O{sub 4}. The high adsorption efficiency for the removal of NPs from water was compared with an untreated membrane. Physisorption, functional group interactions, complexation reactions between metal/metal oxide nanoparticles with various functional groups present in NFM and modified surface properties such as the balance of hydrophilicity/hydrophobicity, surface free energy, and the high surface area of the plasma treated membrane were possible mechanisms of NPs adsorption onto NFM. The regeneration and reusability were tested in five consecutive adsorption/desorption cycles.

  5. NEAR-ABSOLUTE EQUATIONS OF STATE OF DIAMOND, Ag, Al, Au, Cu, Mo, Nb, Pt, Ta, AND W FOR QUASI-HYDROSTATIC CONDITIONS

    Directory of Open Access Journals (Sweden)

    Peter I. Dorogokupets

    2012-01-01

    Full Text Available Using the modified formalism of [Dorogokupets, Oganov, 2005, 2007], equations of state are developed for diamond, Ag, Al, Au, Cu, Mo, Nb, Pt, Ta, and W by simultaneous optimization of shock-wave data, ultrasonic, X-ray, dilatometric and thermochemical measurements in the temperature range from ~100 K to the melting temperature and pressures up to several Mbar, depending on the substance. The room-temperature isotherm is given in two forms: (1 the equation from [Holzapfel, 2001, 2010] which is the interpolation between the low pressure (x≥1 and the pressure at infinite compression (x=0; it corresponds to the Thomas-Fermi model, and (2 the equation from [Vinet et al., 1987]. The volume dependence of the Grüneisen parameter is calculated according to equations from [Zharkov, Kalinin, 1971; Burakovsky, Preston, 2004] with adjustable parameters, t and δ. The room-temperature isotherm and the pressure on the Hugoniot adiabat are determined by three parameters, K', t and δ, and K0 is calculated from ultrasonic measurements. In our study, reasonably accurate descriptions of all of the basic thermodynamic functions of metals are derived from a simple equation of state with a minimal set of adjustable parameters.The pressure calculated from room-temperature isotherms can be correlated with a shift of the ruby R1 line. Simultaneous measurements of the shift and unit cell parameters of metals are conducted in mediums containing helium [Dewaele et al., 2004b; 2008; Takemura, Dewaele, 2008; Takemura, Singh, 2006], hydrogen [Chijioke et al., 2005] and argon [Tang et al., 2010]. According to [Takemura, 2001], the helium medium in diamond anvil cells provides for quasi-hydrostatic conditions; therefore, the ruby pressure scale, that is calibrated for the ten substances, can be considered close to equilibrium or almost absolute. The ruby pressure scale is given as P(GPa=1870⋅Δλ/λ0⋅(1+6⋅Δλ/λ0. The room-temperature isotherms corrected with regard

  6. Study of the reactions resulting in heavy fragment formation in the collisions {sup 40}Ar + Cu, Ag and Au at 8 to 115 MeV/u; Etude des reactions avec formation d`un fragment lourd dans les collisions {sup 40}Ar + Cu, Ag et Au de 8 a 115 MeV/u

    Energy Technology Data Exchange (ETDEWEB)

    Colin, Eric Yves [Universite Claude Bernard Lyon-1, 69 - Lyon (France)

    1998-11-06

    This work concerns the study of nuclear collisions showing a heavy fragment in {sup 40}Ar + Cu, Ag and Au from 8 A MeV to 115 A MeV. The reactions are classified by centrality or collision violence via the multiplicity of charged particles detected in a 4{pi} array. For the most peripheral reactions (low multiplicities) we always find a projectile-like fragment with velocity near to that of the beam and a heavy target-like fragment with very small velocity. For the more central collisions we find the well-known incomplete fusion reactions at 17 and 27 A MeV. Above 27 A MeV two groups of very dissipative reactions are observed, both with high charged particle multiplicities. The first reaction group forms several fragments with Z {<=} 10 and average longitudinal velocity near to that of c.m. These are very rare, and are found only for the highest 1% of multiplicities. They produce a heavy fragment and a forward spray ({theta}{<=}60 angle) of particles with charge going from 1 to {approx_equal}13. The momentum carried out by the spray is randomly spread over all the particles. In spite of the increase of momentum carried by this spray with increasing beam energy, a heavy emission source is formed with 1 - 2 GeV of excitation energy. After a phase of expansion, especially signaled by Z = 1 particles, this source then evaporates many particles. Finally we observed the remaining heavy residual nucleus. (author) 117 refs., 85 figs., 12 tabs.

  7. Etudes de brûleurs adaptés au fonctionnement à faible excès d'air. Première partie Research on Burners Adapted to Operate with Low Air Express. Part One

    Directory of Open Access Journals (Sweden)

    Droin R.

    2006-11-01

    Full Text Available Cet article constitue la synthèse des résultats acquis dans le cadre de la recherche coopérative EDF-IFP concernant l'étude des paramètres aérodynamiques gouvernant le fonctionnement d'un brûleur à 2 veines d'air avec stabilisateur central à aubages. Après avoir rappelé les motivations de l'étude, et présenté les équipements expérimentaux mis en ceuvre à FIFP et l'EDF, on présente les renseignements significatifs obtenus sur un brûleur de petite échelle (500 à 1000 th/h opérant sous d'excès d'air - influence des paramètres aérodynamiques et géométriques sur les conditions de mélange; - optimisation des conditions de réglages et mise en évidence d'un type de stabilisateur d'intérêt pratique, - influence du recyclage de gaz brûlés sur la structure des flammes. This article is a synthesis of the results obtained in the joint EDF-IFP research project on the aerodynamic parameters governing the operating of a two-airstream burner with a central vane swirler. After reviewing the reasons behind the project and describing the experimental equipment used by IFP and EDF, the significant data are given for a small-scale burner (500,000 ta 1,000,000 kcal/h operating with a 2 % air excess. These data include : - the influence of aerodynamic and geometric parameters on the mixture conditions; - optimizing adjustment conditions and finding a practicable swirler type; - the influence of burned-gas recycling on flame structure.

  8. Rate constant for the reaction SO + BrO yields SO2 + Br

    Science.gov (United States)

    Brunning, J.; Stief, L.

    1986-01-01

    The rate of the radical-radical reaction SO + BrO yields SO2 + Br has been determined at 298 K in a discharge flow system near 1 torr pressure with detection of SO and BrO via collision-free sampling mass spectrometry. The rate constant was determined using two different methods: measuring the decay of SO radicals in the presence of an excess of BrO and measuring the decay of BrO radicals in excess SO. The results from the two methods are in reasonable agreement and the simple mean of the two values gives the recommended rate constant at 298 K, k = (5.7 + or - 2.0) x 10 to the -11th cu cm/s. This represents the first determination of this rate constant and it is consistent with a previously derived lower limit based on SO2 formation. Comparison is made with other radical-radical reactions involving SO or BrO. The reaction SO + BrO yields SO2 + Br is of interest for models of the upper atmosphere of the earth and provides a potential coupling between atmospheric sulfur and bromine chemistry.

  9. A study on 170 MeV Au{sup 13+} irradiated nanostructured metal oxide (Fe{sub 2}O{sub 3} and CuO) thin films for PEC applications

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhary, Yatendra S. [Department of Chemistry, Faculty of Science, Dayalbagh Educational Institute, Dayalbagh, Agra 282 005 (India); Khan, Saif A. [Nuclear Science Centre, P.O. Box 10502, New Delhi 110 067 (India); Tripathi, Chanakya [Department of Chemistry, Faculty of Science, Dayalbagh Educational Institute, Dayalbagh, Agra 282 005 (India); Shrivastav, Rohit [Department of Chemistry, Faculty of Science, Dayalbagh Educational Institute, Dayalbagh, Agra 282 005 (India); Satsangi, Vibha R. [Department of Physics and Computer Science, Faculty of Science, Dayalbagh Educational Institute, Dayalbagh, Agra 282 005 (India); Dass, Sahab [Department of Chemistry, Faculty of Science, Dayalbagh Educational Institute, Dayalbagh, Agra 282 005 (India)]. E-mail: sahabdass@yahoo.com

    2006-03-15

    One hundred and seventy MeV Au{sup 13+} irradiation induced modification in photoelectrochemical (PEC) and structural properties of nanostructured 2%Cr-Fe{sub 2}O{sub 3} and CuO thin films has been investigated. The X-ray diffractogram of both oxides indicated diffused nature of peaks with the appearance of crystalline peaks, indicative of partial amorphization taking place at higher fluence i.e. 10{sup 13} ions cm{sup -2}. Upon irradiation, the band gap energy was found to decrease marginally. The irradiated 2%Cr-Fe{sub 2}O{sub 3} samples (fluence 10{sup 12} ions cm{sup -2}) used as working electrode in the PEC cell showed enhanced photocurrent generation. A decrease in photocurrent generation was recorded in case of irradiated 2%Cr-Fe{sub 2}O{sub 3}/CuO at higher fluence i.e. 10{sup 13} ions cm{sup -2} and irradiated CuO sample at fluence 10{sup 12} ions cm{sup -2}, which may be attributed to the creation of greater number of kink sites/dislocations, that are probably acting as recombination centers for photogenerated electrons.

  10. Des territoires de projet au territoire de vie :<br />la création de la coopérative artisanale féminine de Sefrou<br />comme enjeu de modification des systèmes de valeurs sexués.

    OpenAIRE

    Louargant, Sophie

    2006-01-01

    Actuellement, le Maroc s'inscrit dans un processus de recomposition territoriale (régionalisation) et tend à intégrer les principes de genre dans ses politiques de développement. Portés par ses notions globales, les discours d'innovation, de mobilisation et de valorisation des ressources, (promulgués par les représentants du royaume et les instances décisionnelles) placent au cœur du processus de rénovation, le rôle à jouer pour les Marocaines. Les « femmes » ont donc été nommées au titre de ...

  11. Preparation and characterization of poly(glycidyl methacrylate)-grafted magnetic nanoparticles: Effects of the precursor concentration on polyol synthesis of Fe{sub 3}O{sub 4} and [PMDETA]{sub 0}/[CuBr{sub 2}]{sub 0} ratios on SI-AGET ATRP

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Liping; Zhou, Xuyang; Wei, Guyun; Lu, Xiaoduo; Wei, Weiping; Qiu, Jianhua

    2015-12-01

    Highlights: • The nanoparticle size of Fe{sub 3}O{sub 4} increased from 7.3 to 9.6 nm and the saturation magnetization of nanoparticles increased from 59 to 61 emu g{sup −1} with increasing the metal precursor concentration from 0.1 to 0.8 mol L{sup −1}, respectively. • The grafted content of PGMA increased from 4.1 to 23.1 wt% as the [PMDETA]{sub 0}/[CuBr{sub 2}]{sub 0} ratio decreased from 6:1 to 2:1. The PGMA-grafted Fe{sub 3}O{sub 4}@SiO{sub 2} magnetic microparticles were prepared by SI-AGET ATRP. - Abstract: Polymer brushes based on poly(glycidyl methacrylate) (PGMA) have been successfully grafted from the surface of silica coated iron oxide (Fe{sub 3}O{sub 4}@SiO{sub 2}) nanoparticles via surface-initiated activators generated by electron transfer atom transfer radical polymerization (SI-AGET ATRP). The size of the nanoparticles could be adjusted from 7.3 to 9.6 nm by varying the precursor concentration of iron(III) acetylacetonate. The Fe{sub 3}O{sub 4} nanoparticles possessed a highly crystalline structure, and the saturation magnetization of the as-prepared magnetite was strongly related to the particle size. Furthermore, the grafted PGMA content on the magnetic nanoparticles could be controlled by varying the ligand to transition metal ratio in a N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA)/CuBr{sub 2} catalyst system. The maximum grafted content was 23.1% at a ratio of [PMDETA]{sub 0}/[CuBr{sub 2}]{sub 0} = 2:1.

  12. Strata-bound Fe-Co-Cu-Au-Bi-Y-REE deposits of the Idaho Cobalt Belt: Multistage hydrothermal mineralization in a magmatic-related iron oxide copper-gold system

    Science.gov (United States)

    Slack, John F.

    2012-01-01

    Mineralogical and geochemical studies of strata-bound Fe-Co-Cu-Au-Bi-Y-rare-earth element (REE) deposits of the Idaho cobalt belt in east-central Idaho provide evidence of multistage epigenetic mineralization by magmatic-hydrothermal processes in an iron oxide copper-gold (IOCG) system. Deposits of the Idaho cobalt belt comprise three types: (1) strata-bound sulfide lenses in the Blackbird district, which are cobaltite and, less commonly, chalcopyrite rich with locally abundant gold, native bismuth, bismuthinite, xenotime, allanite, monazite, and the Be-rich silicate gadolinite-(Y), with sparse uraninite, stannite, and Bi tellurides, in a gangue of quartz, chlorite, biotite, muscovite, garnet, tourmaline, chloritoid, and/or siderite, with locally abundant fluorapatite or magnetite; (2) discordant tourmalinized breccias in the Blackbird district that in places have concentrations of cobaltite, chalcopyrite, gold, and xenotime; and (3) strata-bound magnetite-rich lenses in the Iron Creek area, which contain cobaltiferous pyrite and locally sparse chalcopyrite or xenotime. Most sulfide-rich deposits in the Blackbird district are enclosed by strata-bound lenses composed mainly of Cl-rich Fe biotite; some deposits have quartz-rich envelopes.Whole-rock analyses of 48 Co- and/or Cu-rich samples show high concentrations of Au (up to 26.8 ppm), Bi (up to 9.16 wt %), Y (up to 0.83 wt %), ∑REEs (up to 2.56 wt %), Ni (up to 6,780 ppm), and Be (up to 1,180 ppm), with locally elevated U (up to 124 ppm) and Sn (up to 133 ppm); Zn and Pb contents are uniformly low (≤821 and ≤61 ppm, respectively). Varimax factor analysis of bulk compositions of these samples reveals geochemically distinct element groupings that reflect statistical associations of monazite, allanite, and xenotime; biotite and gold; detrital minerals; chalcopyrite and sparse stannite; quartz; and cobaltite with sparse selenides and tellurides. Significantly, Cu is statistically separate from Co and As

  13. {sup 27}Al and {sup 45}Sc NMR spectroscopy on ScT{sub 2}Al and Sc(T{sub 0.5}T{sup '}{sub 0.5}){sub 2}Al (T = T{sup '} = Ni, Pd, Pt, Cu, Ag, Au) Heusler phases and superconductivity in Sc(Pd{sub 0.5}Au{sub 0.5}){sub 2}Al

    Energy Technology Data Exchange (ETDEWEB)

    Benndorf, Christopher [Institut fuer Anorganische und Analytische Chemie, Westfaelische Wilhelms-Universitaet Muenster (Germany); Institut fuer Physikalische Chemie, Westfaelische Wilhelms-Universitaet Muenster (Germany); Niehaus, Oliver; Janka, Oliver [Institut fuer Anorganische und Analytische Chemie, Westfaelische Wilhelms-Universitaet Muenster (Germany); Eckert, Hellmut [Institut fuer Physikalische Chemie, Westfaelische Wilhelms-Universitaet Muenster (Germany)

    2015-02-15

    The intermetallic Heusler compounds with ScT{sub 2}Al and Sc(T{sub 0.5}T{sup '}{sub 0.5}){sub 2}Al composition with T = T{sup '} = Ni, Pd, Pt, Cu, Ag, Au were synthesized from the elements by arc melting. They crystallize in the cubic MnCu{sub 2}Al type structure, space group Fm anti 3m. The unit cell parameters were determined by powder X-ray diffraction and the structure of Sc(Pd{sub 0.5}Au{sub 0.5}){sub 2}Al was refined on the basis of single-crystal X-ray diffraction. While the majority of the compounds show Pauli-paramagnetism, ScAu{sub 2}Al and the newly synthesized solid solution Sc(Pd{sub 0.5}Au{sub 0.5}){sub 2}Al exhibit superconductivity with transition temperatures of T{sub C} = 4.4 K and T{sub C} = 3.0(1) K, respectively. The superconducting state of Sc(Pd{sub 0.5}Au{sub 0.5}){sub 2}Al was also investigated by electrical resistivity measurements. All the synthesized compounds were furthermore studied by {sup 27}Al and {sup 45}Sc MAS-NMR spectroscopy. The resonance shifts of the synthesized compounds were determined and in Sc(Pd{sub 1-x}Au{sub x}){sub 2}Al a linear relationship between the resonance shifts and the composition was found. Line broadening effects and enhanced quadrupolar interaction strengths observed in the mixed samples can be attributed to the effect of Pd/Au mixing on the 8c Wyckoff site. The NMR spectroscopic data give no clear evidence for or against Sc/Al site disordering. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Improved composite targets for small scale {sup 64}Cu production comparing Au- and Pt-foils as {sup 64}Ni backing

    Energy Technology Data Exchange (ETDEWEB)

    Walther, M.; Preusche, S.; Fuechtner, F.; Pietzsch, H. J.; Steinbach, J. [Institute of Radiopharmacy, Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany)

    2012-12-19

    Advantages of a stacked assembly of target support components for {sup 64}Cu production via {sup 64}Ni(p,n){sup 64}Cu reaction were reported recently. The present work shows the applicability of these composite targets for beam currents up to 22 {mu}A. Gold and platinum foils were evaluated as {sup 64}Ni backing. The effective specific activity (ESA) and specific activity (SA) were determined by TETA titration at room temperature and at 80 Degree-Sign C and compared with additional copper quantification results via ICP-MS and stripping voltammetric trace analysis (VA).

  15. Magnetic-field tuning of quantum critical fluctuations in CeCu5.9Au0.1

    DEFF Research Database (Denmark)

    Schröder, A.; Aeppli, G.; McMorrow, D.F.

    2002-01-01

    The magnetic field dependence of the quantum critical fluctuations close to the antiferromagnetic transition in CeCu5.9Au0.1 is investigated directly by neutron scattering at TAS7 in Riso in a horizontal magnet. The butterfly-shaped critical wave vector region in the a*c*-plane persists up to H = 1.......8 T (Hparallel toc) and the magnetic spectrum can be represented by the same function used for 0 T, including the unusual exponent alpha = 0.75. The field only changes the dynamics like an effective temperature T-eff = (T-2 + (muH/k(B))(2))(0.5) with a moment mu = 1.3mu(beta). This result is entirely...

  16. μ-Bromido-dibromido-μ-hydroxido-bis­[(4S)-2-halo-6-(4-isopropyl-4,5-dihydro­oxazol-2-yl)pyridine]dicopper(II) (halo: Cl/Br = 3:1)

    OpenAIRE

    Andy Ch. Laungani; Manfred Keller; Bernhard Breit

    2007-01-01

    The crystal structure of the title complex, [Cu2Br3(OH)(C11H13Br0.5Cl1.5N2O)2], consists of two (2-halo-6-oxazolinyl)pyridine·CuBr units bridged by a Br atom and a hydroxide group. The CuII atoms are five-coordinate with an (N,N)BrCu(Br)(OH) distorted tetragonal–pyramidal core, and relatively short contacts to the bridging atoms (Cu—μ-OH and Cu—μ-Br). There are two symmetry-independent half-molecules in the asymmetric unit, which differ only in the arrangement...

  17. The BR eigenvalue algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Geist, G.A. [Oak Ridge National Lab., TN (United States). Computer Science and Mathematics Div.; Howell, G.W. [Florida Inst. of Tech., Melbourne, FL (United States). Dept. of Applied Mathematics; Watkins, D.S. [Washington State Univ., Pullman, WA (United States). Dept. of Pure and Applied Mathematics

    1997-11-01

    The BR algorithm, a new method for calculating the eigenvalues of an upper Hessenberg matrix, is introduced. It is a bulge-chasing algorithm like the QR algorithm, but, unlike the QR algorithm, it is well adapted to computing the eigenvalues of the narrowband, nearly tridiagonal matrices generated by the look-ahead Lanczos process. This paper describes the BR algorithm and gives numerical evidence that it works well in conjunction with the Lanczos process. On the biggest problems run so far, the BR algorithm beats the QR algorithm by a factor of 30--60 in computing time and a factor of over 100 in matrix storage space.

  18. Chitosan-induced Au/Ag nanoalloy dispersed in IL and application in fabricating an ultrasensitive glucose biosensor based on luminol-H₂O₂-Cu²⁺/IL chemiluminescence system.

    Science.gov (United States)

    Chaichi, M J; Alijanpour, S O

    2014-11-01

    A novel glucose biosensor based on the chemiluminescence (CL) detection of enzymatically generated hydrogen peroxide (H₂O₂) was constructed by one covalent immobilization of glucose oxidase (GOD) in glutaraldehyde-functionalized glass cell. In following, chitosan-induced Au/Ag nanoparticles dispersed in ion liquid (IL) were synthesised and immobilized on it. Herein, chitosan molecules acted as both the reducing and stabilizing agent for the preparation of NPs and also, as a coupling agent GOD and Au/Ag alloy NPs. In addition to catalyze luminol CL reaction, these NPs offered excellent catalytic activity toward hydrogen peroxide generation in enzymatic reaction between GOD and glucose. The used IL in fabrication of biosensor increased its stability. Also, IL alongside Cu(2+) accelerated enzymatic and CL reaction kinetic, and decreased luminol CL reaction optimum pH to 7.5 which would enable sensitive and precision determination of glucose. Under optimum condition, linear response range of glucose was found to be 1.0 × 10(-6)-7.5 × 10(-3)M, and detection limit was 4.0 × 10(-7)M. The CL biosensor exhibited good storage stability, i.e., 90% of its initial response was retained after 2 months storage at pH 7.0. The present CL biosensor has been applied satisfactory to analysis of glucose in real serum and urine samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. 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.

  20. Geological, mineralogical and geochemical characteristics of the Radzimowice Au As Cu deposit from the Kaczawa Mountains (Western Sudetes, Poland): an example of the transition of porphyry and epithermal style

    Science.gov (United States)

    Mikulski, Stanislaw Z.

    2005-03-01

    The sheeted quartz sulfide veins of the Radzimowice Au As Cu deposit in the Kaczawa Mountains are related to Upper Carboniferous post-collisional potassic magmatism of the composite Zelezniak porphyry intrusion. Multiple intrusive activity ranges from early calc-alkaline to sub-alkaline and alkaline rocks and is followed by multiple hydrothermal events. Early crustally derived dacitic magma has low mg# (electrum of two generations, and minor maldonite (Au2Bi). Fluid inclusions from various quartz generations co-genetic with base-metal sulfides and associated with carbonates, tellurides and non-refractory gold indicate fluids with moderate salinity (9 15 wt% NaCl equiv.) and a temperature and pressure drop from 350 to 190°C and 1.2 to 0.8 kbar, respectively. According to the result of the sulfur isotope fractionation geothermometer the temperature of base-metal crystallization was in the range from 322 to 289°C. Preliminary results of oxygen isotope studies of quartz from veins indicate a gradual increase in the proportion of meteoric water in the epithermal stage. The gold to silver ratio in ore samples with >3 ppm Au is about 1:5 (geometric mean). Hydrothermal alteration started with sericitization, pyritization, and kaolinitization in vein selvages followed by alkaline hydrothermal alteration of propylitic character (illitization and chloritization), albitization and carbonatization. The mineralization of the Radzimowice deposit is considered as related to alkaline magmatism and is characterized by the superposition of low-sulfidation epithermal mineralization on higher-temperature and deeper-seated mesothermal/porphyry style.

  1. Les livres d’enfants, des manuels de civilité contemporains entre formel et informel? Un exemple: l’enfant noir dans la littérature de jeunesse au Brésil

    Directory of Open Access Journals (Sweden)

    Valéria Barbosa

    2016-11-01

    Full Text Available This article analyses the use of children's literature that is present in a public school context and has a black child as the main character. As cultural artifacts and pedagogical tools, children's books constitute a means of mediation and interaction at the heart of the class. The underlying hypothesis is that this literature represents and plays the role of "contemporary textbooks on civility" by considering these children's books as crucial mediums in education, while implementing the 2003 and 2004 policies for education on ethnic-racial relations. Which representations of the black child are conveyed in the children's books that the PNBE sends, and how are teachers using them in class? This study is based on two methodologies that complement each other: collective interviews conducted with teachers, and direct observations from a third grade class in primary education. It opens the discussion on the possibilities and limitations of school policies, and on how these books are being used by educators, which constitutes a new modality in education for the learning of ethnic-racial diversity at school. Cet article s’intéresse à la littérature de jeunesse, dont le personnage principal est un enfant noir, utilisée dans l’école publique. En tant qu’objets culturels et outils pédagogiques, les livres pour enfants constituent des supports de médiation et d’interaction au sein de la classe. L’hypothèse sous-jacente est que cette littérature joue le rôle de «manuel de civilité contemporain». On prendra donc au sérieux ces petits livres d’enfants devenus l’un des outils du travail pédagogique pour la mise en œuvre des politiques scolaires de 2003-2004 visant l’éducation aux relations ethno-raciales. Quelles représentations de l’enfant noir sont véhiculées dans ces livres d’enfants envoyés par le PNBE et de quelle manière les enseignants en font-ils usage en classe? Cette étude s’appuie sur deux m

  2. La connaissance du climat au Brésil : entre le vernaculaire et le scientifique O conhecimento do clima no Brasil : Entre o vernacular e o científico The knowledge of the climate in Brazil: Between the vernacular and scientific

    Directory of Open Access Journals (Sweden)

    Francisco Mendonça

    2012-06-01

    Full Text Available La connaissance du climat au Brésil résulte du chevauchement entre le savoir vernaculaire et le savoir scientifique, même si dans le cadre académique la conception scientifique et technique est prédominante. Pour la plus grande partie de la population, le savoir vernaculaire (ou traditionnel sur le climat est plus important que le savoir scientifique. Toutefois, dans le cadre de la science, le développement et la consolidation de la climatologie brésilienne ne se font remarquer qu’autour des 70 dernières années. La diffusion du principe de la météorologie dynamique était un des aspects principaux au développement de l’étude des climats brésiliens. L’analyse rythmique des types de temps et les études du climat urbain sont deux exemples du progrès et de l’originalité de la climatologie brésilienne. La question environnementale, l’utilisation des images de satellite et le débat à propos des changements globaux sont les sujets principaux d’intérêt de la climatologie brésilienne dans le temps présent. Un courant d’études lié à la perception du climat a attribué plus d’importance à la connaissance vernaculaire du climat au Brésil, en inaugurant une nouvelle opportunité à la science, une approche plus ouverte, plurielle et donc plus riche que la science strictement moderne.O conhecimento acerca do clima do Brasil é resultado tanto do conhecimento científico quanto do conhecimento vernacular, mesmo se no âmbito da academia prevaleça a perspectiva cientifico-técnica. Para a maioria da população o saber vernacular (tradicional sobre o clima é mais importante que o saber científico. Todavia, do ponto de vista da ciência, o desenvolvimento e a consolidação da climatologia brasileira só veio a ocorrer nos últimos 70 anos. A difusão do príncipio da meteorologia dinâmica constituiu-se num dos principais aspectos para o desenvolvimento dos estudos dos climas do Brasil. Neste período a

  3. Immobilization of [Cu(bpy){sub 2}]Br{sub 2} complex onto a glassy carbon electrode modified with {alpha}-SiMo{sub 12}O{sub 40}{sup 4-} and single walled carbon nanotubes: Application to nanomolar detection of hydrogen peroxide and bromate

    Energy Technology Data Exchange (ETDEWEB)

    Salimi, Abdollah [Department of Chemistry, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of); Research Center for Nanotechnology, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of)], E-mail: absalimi@uok.ac.ir; Korani, Aazam; Hallaj, Rahman; Khoshnavazi, Roshan [Department of Chemistry, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of); Hadadzadeh, Hasan [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2009-03-02

    A simple procedure has been used for preparation of modified glassy carbon electrode with carbon nanotubes and copper complex. Copper complex [Cu(bpy){sub 2}]Br{sub 2} was immobilized onto glassy carbon (GC) electrode modified with silicomolybdate, {alpha}-SiMo{sub 12}O{sub 40}{sup 4-} and single walled carbon nanotubes (SWCNTs){sub .} Copper complex and silicomolybdate irreversibly and strongly adsorbed onto GC electrode modified with CNTs. Electrostatic interactions between polyoxometalates (POMs) anions and Cu-complex, cations mentioned as an effective method for fabrication of three-dimensional structures. The modified electrode shows three reversible redox couples for polyoxometalate and one redox couple for Cu-complex at wide range of pH values. The electrochemical behavior, stability and electron transfer kinetics of the adsorbed redox couples were investigated using cyclic voltammetry. Due to electrostatic interaction, copper complex immobilized onto GC/CNTs/{alpha}-SiMo{sub 12}O{sub 40}{sup 4-} electrode shows more stable voltammetric response compared to GC/CNTs/Cu-complex modified electrode. In comparison to GC/CNTs/Cu-complex the GC/CNTs/{alpha}-SiMo{sub 12}O{sub 40}{sup 4-} modified electrodes shows excellent electrocatalytic activity toward reduction H{sub 2}O{sub 2} and BrO{sub 3}{sup -} at more reduced overpotential. The catalytic rate constants for catalytic reduction hydrogen peroxide and bromate were 4.5({+-}0.2) x 10{sup 3} M{sup -1} s{sup -1} and 3.0({+-}0.10) x 10{sup 3} M{sup -1} s{sup -1}, respectively. The hydrodynamic amperommetry technique at 0.08 V was used for detection of nanomolar concentration of hydrogen peroxide and bromate. Detection limit, sensitivity and linear concentration range proposed sensor for bromate and hydrogen peroxide detection were 1.1 nM and 6.7 nA nM{sup -1}, 10 nM-20 {mu}M, 1 nM, 5.5 nA nM{sup -1} and 10 nM-18 {mu}M, respectively.

  4. Science Museums and the Popularization of Science in Brazil Les musées des sciences et la popularisation de la science au Brésil Museos de ciencias y la popularización de la ciencia en Brasil Museus de Ciência e a popularização do conhecimento no Brasil

    Directory of Open Access Journals (Sweden)

    Cecilia C.B. Cavalcanti

    2011-11-01

    Full Text Available We analyzed the role and importance of the popularization of science in science museums, and its perspectives in Brazil, from the experience we have developed over the years in the Espaço Ciência Viva ; and our participation, observations and studies related to the popularization of science in other science museums and science centers in Brazil and abroad. From an analysis of the historical environment that started in the early 1980’s, to a new era of popularization of science in Brazil and abroad, we briefly evaluate its current state in Brazil and make some considerations on popularization of science, which we need to support for the future economic and social development of our country.Nous avons analysé le rôle, l'importance et l'avenir de la popularisation de la science à travers les musées des sciences au Brésil, en nous basant sur notre expérience acquise au fil des années au sein de Espaço Ciência Viva, ainsi que sur notre participation, nos observations et nos études sur la popularisation de la science dans d'autres musées ou centres dédiés, au Brésil et ailleurs. En partant du contexte historique au début des années 1980 jusqu'à sa situation actuelle, nous évaluons brièvement la popularisation de la science au Brésil, et commentons ce phénomène qu'il est nécessaire de soutenir pour le développement économique et social de notre pays.Analizamos el papel y la importancia de la popularización de la ciencia en los museos científicos, y sus expectativas en Brasil, basados en la experiencia que hemos obtenido a lo largo de los años en el Espaço Ciência Viva, y en nuestra participación, observaciones y estudios relacionados con la popularización de la ciencia en otros museos científicos y centros científicos en Brasil y en el extranjero. Desde un análisis del entorno histórico que empezó a principios de los años 80, a una nueva era de popularización de la ciencia en Brasil y en el mundo, evaluamos

  5. Museus de Ciência e a popularização do conhecimento no Brasil Science Museums and the Popularization of Science in Brazil Les musées des sciences et la popularisation de la science au Brésil Museos de ciencias y la popularización de la ciencia en Brasil

    Directory of Open Access Journals (Sweden)

    Cecilia C.B. Cavalcanti

    2011-11-01

    Full Text Available We analyzed the role and importance of the popularization of science in science museums, and its perspectives in Brazil, from the experience we have developed over the years in the Espaço Ciência Viva; and our participation, observations and studies related to the popularization of science in other science museums and science centers in Brazil and abroad. From an analysis of the historical environment that started in the early 1980’s, to a new era of popularization of science in Brazil and abroad, we briefly evaluate its current state in Brazil and make some considerations on popularization of science, which we need to support for the future economic and social development of our country.Nous avons analysé le rôle, l'importance et l'avenir de la popularisation de la science à travers les musées des sciences au Brésil, en nous basant sur notre expérience acquise au fil des années au sein de Espaço Ciência Viva, ainsi que sur notre participation, nos observations et nos études sur la popularisation de la science dans d'autres musées ou centres dédiés, au Brésil et ailleurs. En partant du contexte historique au début des années 1980 jusqu'à sa situation actuelle, nous évaluons brièvement la popularisation de la science au Brésil, et commentons ce phénomène qu'il est nécessaire de soutenir pour le développement économique et social de notre pays.Analizamos el papel y la importancia de la popularización de la ciencia en los museos científicos, y sus expectativas en Brasil, basados en la experiencia que hemos obtenido a lo largo de los años en el Espaço Ciência Viva, y en nuestra participación, observaciones y estudios relacionados con la popularización de la ciencia en otros museos científicos y centros científicos en Brasil y en el extranjero. Desde un análisis del entorno histórico que empezó a principios de los años 80, a una nueva era de popularización de la ciencia en Brasil y en el mundo, evaluamos

  6. Insights into electrochemical dealloying of Cu out of Au-doped Pt-alloy nanoparticles at the sub-nano-scale

    Directory of Open Access Journals (Sweden)

    Matija Gatalo

    2018-03-01

    Full Text Available Pt alloy nanoparticles present the most probable candidate to be used as the cathode cathodic oxygen reduction reaction electrocatalyst for achieving commercialization targets of the low-temperature fuel cells. It is therefore very important to understand its activation and degradation processes. Besides the ones known from the pure Pt electrocatalysts, the dealloying phenomena possess a great threat since the leached less-noble metal can interact with the polymer membrane or even poison the electrocatalyst. In this study, we present a solution, supported by in-depth advance electrochemical characterization, on how to suppress the removal of Cu from the Pt alloy nanoparticles.

  7. Probing the antiferromagnetism of Ni{sub x}Mn{sub 100-X} with ferromagnetic Ni in exchange-biased bilayers and trilayers on Cu{sub 3}Au(001)

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Muhammad Yaqoob

    2012-07-11

    In this thesis the antiferromagnetism of Ni{sub x}Mn{sub 100-x} thin films in contact with ferromagnetic Ni film(s) in exchange-biased bilayers and trilayers on Cu{sub 3}Au(001) is investigated by means of magneto-optical Kerr effect (MOKE). Ni{sub x}Mn{sub 100-x} ultrathin films (10{<=}x{<=}77) grow in layer-by-layer mode on Cu{sub 3}Au(001) with face-centered tetragonal structure similar to its bulk form. Ni{sub x}Mn{sub 100-x} can couple to out-of-plane (OoP) as well as in-plane (IP) magnetized Ni films, the latter stabilized by Co under-layer deposition. The antiferromagnetic (AFM) ordering temperature (T{sub AFM}) of Ni{sub x}Mn{sub 100-x} films coupled to IP magnetized Ni increases significantly with decreasing x from {approx} 50 to {approx} 20%, whereas only a slight change in T{sub AFM} is observed for bilayers with OoP magnetized Ni as a function of x. The blocking temperature (T{sub b}) is always higher for the IP case than for the OoP except for Ni{sub 50}Mn{sub 50}, where the reverse is true. The critical thickness of Ni{sub x}Mn{sub 100-x} for the onset of exchange bias (EB) decreases significantly for both coupling directions when decreasing x. These results suggest that for decreasing x, the non-collinear 3Q-like spin structure of Ni{sub x}Mn{sub 100-x} deviates, driven by composition-dependent strain, from a more-OoP to a more-IP configuration with an associated increase in magnetic anisotropic energy to establish EB at smaller Ni{sub x}Mn{sub 100-x} thicknesses. Trilayers of Ni/Ni{sub x}Mn{sub 100-x}/Ni (17{>=}x{>=}25) on Cu{sub 3}Au(001) are studied in detail, while manipulating the easy axis of magnetization of one or both of the FM Ni layers by the deposition of an adjacent Co layer. For the trilayers the exchange bias field H{sub eb} is found to be always smaller than in the corresponding bilayers at similar temperatures. This difference of Heb increases as the thickness of the Ni{sub x}Mn{sub 100-x} layer decreases. At reduced thickness (27 ML

  8. La sous-traitance au Brésil : un phénomène à la fois ancien et nouveau Subcontracting in Brazil: a phenomenon both new and old La subcontratación en Brasil : un fenómeno antiguo y nuevo a la vez

    Directory of Open Access Journals (Sweden)

    Graça Druck

    2009-05-01

    Full Text Available L’objectif de l’article est de discuter la sous-traitance aujourd’hui au Brésil. Nous discutons dans l’article le processus de flexibilisation et de précarisation du travail au Brésil, en prenant comme objet d’étude la sous-traitance, en tant qu’une des principales politiques de gestion et d’organisation du travail dans le cadre de la restructuration productive. Nous présentons une synthèse du processus de sous-traitance observé ces dernières années dans le pays, sous ses anciennes et nouvelles modalités, et nous analysons les résultats empiriques récents sur la sous-traitance dans des entreprises industrielles à haut risque pour l’environnement et la santé des travailleurs, dans la Région Métropolitaine de Salvador/Bahia/Brésil, de même que nous indiquons les principales de formes de résistance et de contre-pouvoirs construits contre la précarisation du travail et la sous-traitance.The purpose of the article is to discuss current subcontracting in Brazil. Our study subject « subcontracting as one of the main work management and organization policies in the framework of productive restructurings » used to discuss the work flexilibization and precarization process in Brazil. We present a synthesis of the subcontracting process observed in recent years in this country, under its old and new conditions, and we analyze the recent empirical results on subcontracting in industrial enterprises at high risk to the environment and workers’ health, in the metropolitan region of Salvador/Bahia, Brazil. We also identify the main forms of resistance and the counterbalances developed against work precarization and subcontracting.El objetivo de este artículo es discutir la tercerización en el Brasil contemporáneo. Se discute el proceso de flexibilización y de precarización del trabajo en Brasil, tomando como objeto de estudio la subcontratación como una de las principales políticas de gestión y de organizaci

  9. Qualité de vie et vécu de la maladie, avant et après hystérectomie vaginale, chez les femmes admises au Centre Hospitalier Universitaire de Brazzaville

    Science.gov (United States)

    Mbongo, Jean Alfred; Mouanga, Alain; Miabaou, Didace Massamba; Nzelie, Aya; Iloki, Léon Hervé

    2016-01-01

    Toute maladie est un mal en soi qu’il faut éradiquer car elle altère souvent de façon significative la qualité de la vie. L’hystérectomie vaginale est indiquée pour les patientes qui présentent certaines affections gynécologiques graves, elle est donc bénéfique mais, peut également avoir une répercussion néfaste sur la qualité de vie de la femme. Ainsi nous avons voulu explorer le vécu de la maladie et de l’hystérectomie vaginale (HV) des femmes avant et après l’intervention chirurgicale. Nous avons effectué une étude prospective qualitative, à recueil clinique sur une période de 12 mois; qui a concerné les femmes, ayant subi une hystérectomie vaginale. Celles n’ayant pas accepté de participer à l’étude, ou n’ayant pas de contact téléphonique n’ont pas été incluses. Pendant la maladie, le vécu des femmes a été: l’inconfort sexuel 26/40 (65%); les saignements génitaux 12/40 (30%); les douleurs pelviennes 13/40 (32,5%). En Post-opératoire, ont été noté les dyspareunies transitoires30/40 (75%) ; les céphalées secondaires à l’anesthésie 4/40 (10%). Le vécu psychologique a été dominé avant l’HV par la peur de la chirurgie chez toutes les patientes, les troubles du sommeil 38/40 (95%), l’angoisse 30 /40(75%), un sentiment de honte lié aux difficultés à accomplir l’acte sexuel en raison du prolapsus 26/40(65%) et/ ou en raison des saignements génitaux, dus au fibrome utérin 14/40(35%). Le sentiment de la perte de féminité était déclaré par 26/40 femmes porteuses de prolapsus utérin (65%), la modification de l’estime de soi 26/40 (65%). Ces appréciations subjectives ont été améliorées avec l’HV, contre balançant la perte de leur organe de reproduction. Aucune information n’a été donnée par les femmes à leurs proches et aux membres de la famille avant la chirurgie, traduisant ainsi leur sentiment de gène ou de honte. L’arrêt des symptômes a été observé dans tous les

  10. Lattice parameter change due to electronic excitation in oxygen-deficient EuBa 2Cu 3O y

    Science.gov (United States)

    Ishikawa, N.; Iwase, A.; Chimi, Y.; Michikami, O.; Wakana, H.; Hashimoto, T.

    2002-05-01

    The films of EuBa 2Cu 3O y (EBCO) having different oxygen contents are irradiated with 125 MeV Br, 200 MeV I and 200 MeV Au, and their irradiation-induced change in c-axis lattice parameter is measured. Although the electrical resistivity of EBCO is drastically changed by varying oxygen content from y=7 to 6.1, almost the same slope of c-axis lattice parameter as a function of fluence is observed. This result shows that the electrical resistivity is not necessarily a dominant parameter that determines the electronic excitation effect.

  11. Photochromic conversions of the Br/sub 2//sup -/ radical ion

    Energy Technology Data Exchange (ETDEWEB)

    Plyusnin, V.F.

    The photolysis of frozen solutions of HBr, containing complexes of FeBr/sub 3/ or CuBr/sub 4//sup 2 -/, is discussed. The primary product of the photoreduction of complexes is the radical ion Br/sub 2//sup -/. Irradiation in the absorption band of this particle leads to its disappearance. However, it can be regulated by photolysis of the sample in a shorter-wave region of the spectrum. The processes leading to this photochrome conversion are discussed.

  12. Synthesis, Crystal Structure, and Electroconducting Properties of a 1D Mixed-Valence Cu(I–Cu(II Coordination Polymer with a Dicyclohexyl Dithiocarbamate Ligand

    Directory of Open Access Journals (Sweden)

    Kenji Nakatani

    2015-04-01

    Full Text Available A new mixed-valence Cu(I–Cu(II 1D coordination polymer, [CuI4CuIIBr4(Cy2dtc2]n, with an infinite chain structure is synthesized by the reaction of Cu(Cy2dtc2 (Cy2dtc− = dicyclohexyl dithiocarbamate, C13H22NS2 with CuBr·S(CH32. The as-synthesized polymer consists of mononuclear copper(II units of CuII(Cy2dtc2 and tetranuclear copper(I cluster units, CuI4Br4. In the cluster unit, all the CuI ions have distorted trigonal pyramidal coordination geometries, and the CuI–CuI or CuI–CuII distances between the nearest copper ions are shorter than the sum of van der Waals radii for Cu–Cu.

  13. μ-Bromido-dibromido-μ-hydroxido-bis-[(4S)-2-halo-6-(4-isopropyl-4,5-dihydro-oxazol-2-yl)pyridine]dicopper(II) (halo: Cl/Br = 3:1).

    Science.gov (United States)

    Laungani, Andy Ch; Keller, Manfred; Breit, Bernhard

    2007-12-06

    The crystal structure of the title complex, [Cu(2)Br(3)(OH)(C(11)H(13)Br(0.5)Cl(1.5)N(2)O)(2)], consists of two (2-halo-6-oxazolin-yl)pyridine·CuBr units bridged by a Br atom and a hydroxide group. The Cu(II) atoms are five-coordinate with an (N,N)BrCu(Br)(OH) distorted tetra-gonal-pyramidal core, and relatively short contacts to the bridging atoms (Cu-μ-OH and Cu-μ-Br). There are two symmetry-independent half-mol-ecules in the asymmetric unit, which differ only in the arrangement of the isopropyl group. The mol-ecules are located on a twofold rotation axes.

  14. Pathways for the OH + Br2 → HOBr + Br and HOBr + Br → HBr + BrO Reactions.

    Science.gov (United States)

    Wang, Hongyan; Qiu, Yudong; Schaefer, Henry F

    2016-02-11

    The OH radical reaction with Br2 and the subsequent reaction HOBr + Br are of exceptional importance to atmospheric chemistry and environmental chemistry. The entrance complex, transition state, and exit complex for both reactions have been determined using the coupled-cluster method with single, double, and perturbative triple excitations CCSD(T) with correlation consistent basis sets up to size cc-pV5Z and cc-pV5Z-PP. Coupled cluster effects with full triples (CCSDT) and full quadruples (CCSDTQ) are explicitly investigated. Scalar relativistic effects, spin-orbit coupling, and zero-point vibrational energy corrections are evaluated. The results from the all-electron basis sets are compared with those from the effective core potential (ECP) pseudopotential (PP) basis sets. The results are consistent. The OH + Br2 reaction is predicted to be exothermic 4.1 ± 0.5 kcal/mol, compared to experiment, 3.9 ± 0.2 kcal/mol. The entrance complex HO···BrBr is bound by 2.2 ± 0.2 kcal/mol. The transition state lies similarly well below the reactants OH + Br2. The exit complex HOBr···Br is bound by 2.7 ± 0.6 kcal/mol relative to separated HOBr + Br. The endothermicity of the reaction HOBr + Br → HBr + BrO is 9.6 ± 0.7 kcal/mol, compared with experiment 8.7 ± 0.3 kcal/mol. For the more important reverse (exothermic) HBr + BrO reaction, the entrance complex BrO···HBr is bound by 1.8 ± 0.6 kcal/mol. The barrier for the HBr + BrO reaction is 6.8 ± 0.9 kcal/mol. The exit complex (Br···HOBr) for the HBr + BrO reaction is bound by 1.9 ± 0.2 kcal/mol with respect to the products HOBr + Br.

  15. Lattice parameter change due to electronic excitation in oxygen-deficient EuBa{sub 2}Cu{sub 3}O{sub y}

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, N. E-mail: ishikawa@popsvr.tokai.jaeri.go.jp; Iwase, A.; Chimi, Y.; Michikami, O.; Wakana, H.; Hashimoto, T

    2002-05-01

    The films of EuBa{sub 2}Cu{sub 3}O{sub y} (EBCO) having different oxygen contents are irradiated with 125 MeV Br, 200 MeV I and 200 MeV Au, and their irradiation-induced change in c-axis lattice parameter is measured. Although the electrical resistivity of EBCO is drastically changed by varying oxygen content from y=7 to 6.1, almost the same slope of c-axis lattice parameter as a function of fluence is observed. This result shows that the electrical resistivity is not necessarily a dominant parameter that determines the electronic excitation effect.

  16. La diffusion du semis direct au Brésil, diversité des pratiques et logiques territoriales : l’exemple de la région d’Itaipu au Paraná A difusão do plantio direto no Brasil, diversidade das práticas e lógicas territoriais : o exemplo da região de Itaipú, Paraná

    Directory of Open Access Journals (Sweden)

    Ivo Mello

    2011-10-01

    Full Text Available Le semis direct est un système de production fondé sur le non-travail du sol. Il intègre une série de pratiques agricoles qui permettent de protéger les sols cultivés de l’érosion, de réduire les consommations de carburants, voire d’augmenter les rendements. Le large succès du semis direct au Brésil, contribue à la compétitivité et à la forte croissance de ses productions tout en préservant les sols. Le système complet du semis direct sous couvert est fondé sur trois principes : le non-labour, la couverture permanente du sol et des rotations culturales. Sur le terrain, les pratiques sont variées et nombre d’agriculteurs n’appliquent pas les deux derniers principes. La technique est le plus souvent associée à l’emploi d’herbicides qui présentent des risques de pollution, encore peu appréhendés au Brésil. Le semis direct s’est implanté dans le Sud du pays dans les années 1970-1990. De là, le système, mis en œuvre par les gaúchos, s’est rapidement étendu dans d’autres régions, particulièrement dans le centre et le nord du pays. Dans ce travail, les pratiques du semis direct sont étudiées à deux échelles. La région du Paraná 3, située en bordure orientale du lac de barrage d’Itaipu, montre que la pratique du semis direct, adoptée par de nombreux agriculteurs intègre également la protection du barrage afin de limiter l’érosion et la pollution de l’eau. A l’échelle des exploitations, des entretiens avec trois producteurs du Paraná et du Rio Grande do Sul, réalisant du semis direct sous couvert, présentent les pratiques et les raisonnements qui leurs sont associés. Ces entretiens nous montrent que l’adoption d’un système d’agriculture de conservation repose sur une révision profonde du mode de production et sur l’appropriation des connaissances relatives aux processus naturels. Si le succès du semis direct s’appuie sur l’augmentation des gains économiques, ce

  17. Low-temperature solution synthesis of the non-equilibrium ordered intermetallic compounds Au3Fe, Au3Co, and Au3Ni as nanocrystals.

    Science.gov (United States)

    Vasquez, Yolanda; Luo, Zhiping; Schaak, Raymond E

    2008-09-10

    Alloys and intermetallic compounds of Au with the 3d transition metals Fe, Co, and Ni are nonequilibrium phases that have many useful potential applications as catalytic, magnetic, optic, and multifunctional magneto-optic materials. However, the atomically ordered Au-M (M = Fe, Co, Ni) intermetallics are particularly elusive from a synthetic standpoint. Here we report the low-temperature solution synthesis of the L12 (Cu3Au-type) intermetallic compounds Au3Fe, Au3Co, and Au3Ni using n-butyllithium as a reducing agent. Reaction pathway studies for the Au3Co system indicate that Au nucleates first, followed by Co incorporation to form the intermetallic. The nonequilibrium intermetallic nanocrystals have been characterized by powder XRD, TEM, EDS, selected area electron diffraction, and nanobeam electron diffraction, which collectively confirm the compositions and superlattice structures.

  18. Gold Nanoparticles with Stably Embedded Cu-64 and Their Use in Nanoparticle Research

    DEFF Research Database (Denmark)

    Jensen, A.I.; Frellsen, Anders Floor; Hansen, A. E.

    2016-01-01

    64Cu is a popular radionuclide for PET imaging and when 64Cu2+ is mixed with gold nanoparticles (AuNPs) it adheres to the gold surface. Taking advantage of this, we developed methods to trap the 64Cu within the AuNPs by embedding under additional layers of gold. This resulted in radiolabeling eff...

  19. Anomalous \\phi Meson Suppression in Au+Au Collisions at \\sqrt{s_{NN}}=200 GeV Measured by the PHENIX Experiment at RHIC

    CERN Document Server

    Naglis, Maxim

    2009-01-01

    The PHENIX experiment at RHIC has measured the \\phi-meson production at mid-rapidity in p+p, d+Au, Cu+Cu and Au+Au collisions at \\sqrt{s_{NN}}=200 GeV via the K^+K^- decay mode. The transverse momentum spectra of the \\phi-meson and the nuclear modification factor as a function of centrality are reviewed here.

  20. Giant magnetoresistance of dissymmetrical Co/Au multilayers

    Science.gov (United States)

    Kolb, E.; Walker, M. J.; Vélu, E.; Howson, M. A.; Veillet, P.; Greig, D.; Renard, J. P.; Dupas, C.

    1996-04-01

    Results are presented for the magnetoresistance (MR) of sapphire/Nb 3/Cu 3/Au 8/(Co/Au 8) n dissymmetrical multilayers built by alternating a 0.3 nm discontinuous Co layer with a 0.7 nm continuous one. The observed enhanced MR is related to a higher spin scattering asymmetry for the granular Co layers.

  1. Changements d’occupation du sol et leurs impacts climatiques au Mato Grosso, Brésil Mudanças no uso da terra e impactos climaticos no Mato Grosso, Brasil Land cover changes and their climatic impacts in Mato Grosso, Brazil

    Directory of Open Access Journals (Sweden)

    Dubreuil

    2010-03-01

    Full Text Available Les changements d’occupation du sol (déforestation, urbanisation en Amazonie brésilienne ont des conséquences sensibles sur les températures à l’échelle locale. Cet article présente une comparaison sur les températures du mois de juillet 2007 entre la zone urbanisée, la zone défrichée au profit de pâturages et celle couverte par la forêt dans la région d’Alta Floresta (Mato Grosso. Ces variations sont marquées en journée mais surtout en début et fin de journée (avec les écarts importants entre les températures de 2°C à 4,3°C entre le secteur forestier et le centre-ville. Le secteur défriché apparaît toujours globalement plus chaud que la région forestière. Une seconde partie de l’article concerne l’étude de l’îlot de chaleur urbain pour 3 villes du Mato Grosso : Rondonopolis, Sorriso et Sinop. Les observations réalisées par la méthode des transects mobiles en juillet 2009 montrent que les températures sont plus élevées dans les secteurs urbanisés denses, même si des différences existent au sein même des villes. L’effet d’îlot de chaleur urbain est particulièrement bien marqué surtout pendant la nuit et la saison sèche mais, localement, le rôle de la topographie et des parcs est bien sensible également (îlots de fraîcheur.Mudanças no uso da terra (desmatamento e urbanização na Amazônia brasileira tem um efeito significativo sobre as temperaturas ao nível local. Este artigo compara as temperaturas de Julho de 2007 entre a área urbana, a área desmatada por pastagem e floresta na região de Alta Floresta (Mato Grosso. Estas diferenças são marcadas durante o dia, mas especialmente no início e no fim do dia (com diferenças significativas entre as temperaturas de 2 ° C a 4,3 ° C entre o setor florestal e o centro da cidade. A área desmatada é geralmente mais quente que a área florestal. A segunda parte do artigo trata-se do estudo da ilha de calor urbano de três cidades

  2. Bréal, un antinaturalisme d’inspiration humboldtienne

    Directory of Open Access Journals (Sweden)

    Babu Jean-Philippe

    2014-07-01

    Full Text Available Dans De la forme et de la fonction des mots, Bréal formulait, dès 1866, outre une critique générale du formalisme de la philologie comparative depuis Bopp, une thèse radicalement opposée à l’orientation naturaliste de l’évolutionnisme linguistique de Schleicher. Cette thèse, que nous prendrons le risque de définir comme thèse du primat de la fonction sur la forme linguistique, est au coeur de ce programme de linguistique générale pour lequel Bréal allait forger, quelques années plus tard, le mot de sémantique. Fortement marqué par la notion humboldtienne d’innere Sprachform, Bréal, contrairement à Saussure, n'abandonnera jamais le changement linguistique au hasard de l'histoire et maintiendra l'intelligence comme premier moteur des langues, quitte à poser la nécessité de repenser cette intelligence.

  3. A spectrophotometric study of aqueous Au(III) halide-hydroxide complexes at 25-80 °C

    Science.gov (United States)

    Usher, Al; McPhail, D. C.; Brugger, Joël

    2009-06-01

    The mobility and transport of gold in low-temperature waters and brines is affected by the aqueous speciation of gold, which is sensitive in particular to pH, oxidation and halide concentrations. In this study, we use UV-Vis spectrophotometry to identify and measure the thermodynamic properties of Au(III) aqueous complexes with chloride, bromide and hydroxide. Au(III) forms stable square planar complexes with hydroxide and halide ligands. Based on systematic changes in the absorption spectra of solutions in three binary systems NaCl-NaBr, NaCl-NaOH and NaBr-NaOH at 25 °C, we derived log dissociation constants for the following mixed and end-member halide and hydroxide complexes: [AuCl 3Br] -, [AuCl 2Br 2] -, [AuBr 3Cl] - and [AuBr 4] -; [AuCl 3(OH)] -, [AuCl 2(OH) 2] -, [AuCl(OH) 3] - and [Au(OH) 4] -; and [AuBr 3(OH)] -, [AuBr 2(OH) 2] - and [AuBr(OH) 3] -. These are the first reported results for the mixed chloride-bromide complexes. Increasing temperature to 80 °C resulted in an increase in the stability of the mixed chloride-bromide complexes, relative to the end-member chloride and bromide complexes. For the [AuCl (4-n)(OH) n] - series of complexes ( n = 0-4), there is an excellent agreement between our spectrophotometric results and previous electrochemical results of Chateau et al. [Chateau et al. (1966)]. In other experiments, the iodide ion (I -) was found to be unstable in the presence of Au(III), oxidizing rapidly to I 2(g) and causing Au to precipitate. Predicted Au(III) speciation indicates that Au(III) chloride-bromide complexes can be important in transporting gold in brines with high bromide-chloride ratios (e.g., >0.05), under oxidizing (atmospheric), acidic (pH hydrometallurgy and medicine.

  4. Au-HKUST-1 Composite Nanocapsules: Synthesis with a Coordination Replication Strategy and Catalysis on CO Oxidation.

    Science.gov (United States)

    Liu, Yongxin; Zhang, Jiali; Song, Lingxiao; Xu, Wenyuan; Guo, Zanru; Yang, Xiaomin; Wu, Xiaoxin; Chen, Xi

    2016-09-07

    A novel coordination replication of Cu2O redox-template strategy is reported to efficiently fabricate Au-HKUST-1 composite nanocapsule, with a HKUST-1 sandwich shell and an embedded Au nanoparticles layer. The novel synthesis procedure involves forming Au nanoparticles on the surface of Cu2O, transforming partial Cu2O into HKUST-1 shell via coordination replication, and removing the residual Cu2O by acid. The as-prepared Au-HKUST-1 composite nanocapsules displayed high catalytic activity on CO oxidation.

  5. Role of Brønsted acid in selective production of furfural in biomass pyrolysis.

    Science.gov (United States)

    Zhang, Haiyan; Liu, Xuejun; Lu, Meizhen; Hu, Xinyue; Lu, Leigang; Tian, Xiaoning; Ji, Jianbing

    2014-10-01

    In this work, the role of Brønsted acid for furfural production in biomass pyrolysis on supported sulfates catalysts was investigated. The introduction of Brønsted acid was shown to improve the degradation of polysaccharides to intermediates for furfural, which did not work well when only Lewis acids were used in the process. Experimental results showed that CuSO4/HZSM-5 catalyst exhibited the best performance for furfural (28% yield), which was much higher than individual HZSM-5 (5%) and CuSO4 (6%). The optimum reaction conditions called for the mass ratio of CuSO4/HZSM-5 to be 0.4 and the catalyst/biomass mass ratio to be 0.5. The recycled catalyst exhibited low productivity (9%). Analysis of the catalysts by Py-IR revealed that the CuSO4/HZSM-5 owned a stronger Brønsted acid intensity than HZSM-5 or the recycled CuSO4/HZSM-5. Therefore, the existence of Brønsted acid is necessary to achieve a more productive degradation of biomass for furfural. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Origin of sulfur and crustal recycling of copper in polymetallic (Cu-Au-Co-Bi-U ± Ag) iron-oxide-dominated systems of the Great Bear Magmatic Zone, NWT, Canada

    Science.gov (United States)

    Acosta-Góngora, P.; Gleeson, S. A.; Samson, I. M.; Corriveau, L.; Ootes, L.; Jackson, S. E.; Taylor, B. E.; Girard, I.

    2017-06-01

    The Great Bear Magmatic Zone, in northwest Canada, contains numerous polymetallic mineral occurrences, prospects, and deposits of the iron oxide copper-gold deposit (IOCG) family. The mineralization is hosted by the Treasure Lake Group and igneous rocks of the Great Bear arc and was deposited concomitantly with the arc magmatism (ca. 1.88 to 1.87 Ga). In situ δ 34S (n = 48) and δ 65Cu (n = 79) analyses were carried out on ore-related sulfides from a number of these systems. The δ 34S values mainly vary between 0 and +5‰, consistent with derivation of sulfur from the mantle. Lower δ 34S values (-7.7 to +1.4‰) from the Sue-Dianne breccia may indicate SO2 disproportionation of a magmatic hydrothermal fluid. The δ 65Cu values vary between -1.2 and -0.3‰, and are lower than the igneous δ 65Cu range of values (0.0 ± 0.27‰). The S and Cu isotopic data are decoupled, which suggests that Cu (and possibly some S) was dissolved and remobilized from supracrustal rocks during early stages of alteration (e.g., sodic alteration) and then precipitated by lower temperature, more oxidizing fluids (e.g., Ca-Fe-K alteration). A limited fluid inclusion dataset and δ 13C and δ 18O values are also presented. The δ 18Ofluid values are consistent with a magmatic origin or a host-rock equilibrated meteoric water source, whereas the δ 13Cfluid values support a marine carbonate source. Combined, the S and Cu isotopic data indicate that while the emplacement of the Great Bear magmatic bodies may have driven fluid convection and may be the source of fluids and sulfur, metals such as Cu could have been recycled from crustal sources.

  7. Magnetic fluctuations near a quantum phase transition in CeCu5.9Au0.1

    DEFF Research Database (Denmark)

    Schröder, A.; Aeppli, G.; Bucher, E.

    1998-01-01

    , most intense at wave vectors Q(1), near(1,0,0), close to the magnetic ordering vector found at higher Au-concentration. The energy dependence can be best described by a modified quasielastic Lorentzian with power alpha = 0.7. Down to the lowest temperature of 0.07 K the relaxation rate Gamma remains...

  8. AuCuZn_2合金のマルテンサイト変態に前駆する異常現象(合金の相変態とその前駆現象,科研費研究会報告)

    OpenAIRE

    中嶋, 貞雄

    1986-01-01

    AuCuZn_2合金β_1相について中性子線及びX線による研究を行い、マルテンサイト変態に前駆して現れる異常散乱ピークの性質を明らかにし、又(110)[110]TA,フォノン分散曲線から(110)面間結合力の性質を解析した。得られた結果は、異なる条件下で出現可能なマルテンサイト構造を示唆している。

  9. μ-Bromido-dibromido-μ-hydroxido-bis[(4S-2-halo-6-(4-isopropyl-4,5-dihydrooxazol-2-ylpyridine]dicopper(II (halo: Cl/Br = 3:1

    Directory of Open Access Journals (Sweden)

    Andy Ch. Laungani

    2008-01-01

    Full Text Available The crystal structure of the title complex, [Cu2Br3(OH(C11H13Br0.5Cl1.5N2O2], consists of two (2-halo-6-oxazolinylpyridine·CuBr units bridged by a Br atom and a hydroxide group. The CuII atoms are five-coordinate with an (N,NBrCu(Br(OH distorted tetragonal–pyramidal core, and relatively short contacts to the bridging atoms (Cu—μ-OH and Cu—μ-Br. There are two symmetry-independent half-molecules in the asymmetric unit, which differ only in the arrangement of the isopropyl group. The molecules are located on a twofold rotation axes.

  10. From the Ternary Eu(Au/In)2 and EuAu4(Au/In)2 with Remarkable Au/In Distributions to a New Structure Type: The Gold-Rich Eu5Au16(Au/In)6 Structure.

    Science.gov (United States)

    Steinberg, Simon; Card, Nathan; Mudring, Anja-Verena

    2015-09-08

    The ternary Eu(Au/In)2 (EuAu(0.46)In(1.54(2))) (I), EuAu4(Au/In)2 (EuAu(4+x)In(2-x) with x = 0.75(2) (II), 0.93(2), and 1.03(2)), and Eu5Au16(Au/In)6 (Eu5Au(17.29)In(4.71(3))) (III) have been synthesized, and their structures were characterized by single-crystal X-ray diffraction. I and II crystallize with the CeCu2-type (Pearson Symbol oI12; Imma; Z = 4; a = 4.9018(4) Å; b = 7.8237(5) Å; c = 8.4457(5) Å) and the YbAl4Mo2-type (tI14; I4/mmm; Z = 2; a = 7.1612(7) Å; c = 5.5268(7) Å) and exhibit significant Au/In disorder. I is composed of an Au/In-mixed diamond-related host lattice encapsulating Eu atoms, while the structure of II features ribbons of distorted, squared Au8 prisms enclosing Eu, Au, and In atoms. Combination of these structural motifs leads to a new structure type as observed for Eu5Au16(Au/In)6 (Eu5Au(17.29)In(4.71(3))) (oS108; Cmcm; Z = 4; a = 7.2283(4) Å; b = 9.0499(6) Å; c = 34.619(2) Å), which formally represents a one-dimensional intergrowth of the series EuAu2-"EuAu4In2". The site preferences of the disordered Au/In positions in II were investigated for different hypothetical "EuAu4(Au/In)2" models using the projector-augmented wave method and indicate that these structures attempt to optimize the frequencies of the heteroatomic Au-In contacts. A chemical bonding analysis on two "EuAu5In" and "EuAu4In2" models employed the TB-LMTO-ASA method and reveals that the subtle interplay between the local atomic environments and the bond energies determines the structural and site preferences for these systems.

  11. Stig Brøgger's Artists' Books

    DEFF Research Database (Denmark)

    Ørum, Tania; Hvis Kromann, Thomas

    Introduction and presentation of the many artist's books made by the Danish artist Stig Brøgger......Introduction and presentation of the many artist's books made by the Danish artist Stig Brøgger...

  12. Brændeovn med autopilot

    DEFF Research Database (Denmark)

    Illerup, Jytte Boll

    2013-01-01

    Ved at sætte brændeovnen på autopilot opnår man en bedre energiudnyttelse og en markant reduktion af luftforurenende stoffer. Automatisk styring af brændeovnen giver lige så lave emissioner hos forbrugeren som på testinstitutter, viser et forskningsprojekt mellem den jyske brændeovnproducent HWAM...

  13. Un nouvel oxyde naturel de Au et Sb

    Science.gov (United States)

    Johan, Zdenek; Šrein, Vladimir

    1998-04-01

    A gold-antimony X-ray amorphous oxide, resulting from a hydrothermal alteration of aurostibite, AuSb 2, occurs in the Krásná Hora gold deposit, Czech Republic. Its reflectivity is close to that of goethite. The average composition obtained by electron microprobe analyses (wt. %) is: Au - 68.32; Cu - 0.10; Sb - 21.26; As - 0.30; Si - 0.21; O - 8.44; total 98.63. This yields the empirical formula (Au 0.677Cu 0.003Sb 0.341As 0.008) 1.029O. The[(Au + Cu)/(Sb + As)] at ratio varies from 1.86 to 1.95. Among possible formulae satisfying the equilibrium of charges, that implying unique valence states for Au and/or Sb was retained. It can be written Au 1+2Sb 3+O 2(OH) with the theoretical composition (wt, %): Au - 69.76; Sb - 21.54; O - 8.50; H - 0.20. This Au- and Sb-bearing oxide is associated with native gold, electrum, aurostibite, arsenopyrite and pyrite in a quartz gangue. The powder pattern of AuSbO 3 was indexedon an orthorhombic unit-cell with a = 5.00(2); b = 12.46(4); c = 5.43(2) Å, Z = 4, Q calc = 7.20 g.cm 3, assuming a replacement of Sb 3+ by Au 3+ in the valentinite-type crystal structure.

  14. The coupled geochemistry of Au and As in pyrite from hydrothermal ore deposits

    Science.gov (United States)

    Deditius, Artur P.; Reich, Martin; Kesler, Stephen E.; Utsunomiya, Satoshi; Chryssoulis, Stephen L.; Walshe, John; Ewing, Rodney C.

    2014-09-01

    The ubiquity of Au-bearing arsenian pyrite in hydrothermal ore deposits suggests that the coupled geochemical behaviour of Au and As in this sulfide occurs under a wide range of physico-chemical conditions. Despite significant advances in the last 20 years, fundamental factors controlling Au and As ratios in pyrite from ore deposits remain poorly known. Here we explore these constraints using new and previously published EMPA, LA-ICP-MS, SIMS, and μ-PIXE analyses of As and Au in pyrite from Carlin-type Au, epithermal Au, porphyry Cu, Cu-Au, and orogenic Au deposits, volcanogenic massive sulfide (VHMS), Witwatersrand Au, iron oxide copper gold (IOCG), and coal deposits. Pyrite included in the data compilation formed under temperatures from ∼30 to ∼600 °C and in a wide variety of geological environments. The pyrite Au-As data form a wedge-shaped zone in compositional space, and the fact that most data points plot below the solid solubility limit defined by Reich et al. (2005) indicate that Au1+ is the dominant form of Au in arsenian pyrite and that Au-bearing ore fluids that deposit this sulfide are mostly undersaturated with respect to native Au. The analytical data also show that the solid solubility limit of Au in arsenian pyrite defined by an Au/As ratio of 0.02 is independent of the geochemical environment of pyrite formation and rather depends on the crystal-chemical properties of pyrite and post-depositional alteration. Compilation of Au-As concentrations and formation temperatures for pyrite indicates that Au and As solubility in pyrite is retrograde; Au and As contents decrease as a function of increasing temperature from ∼200 to ∼500 °C. Based on these results, two major Au-As trends for Au-bearing arsenian pyrite from ore deposits are defined. One trend is formed by pyrites from Carlin-type and orogenic Au deposits where compositions are largely controlled by fluid-rock interactions and/or can be highly perturbed by changes in temperature and

  15. Au/Pd core-shell nanoparticles with varied hollow Au cores for enhanced formic acid oxidation

    Science.gov (United States)

    Hsu, Chiajen; Huang, Chienwen; Hao, Yaowu; Liu, Fuqiang

    2013-03-01

    A facile method has been developed to synthesize Au/Pd core-shell nanoparticles via galvanic replacement of Cu by Pd on hollow Au nanospheres. The unique nanoparticles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, ultraviolet-visible spectroscopy, and electrochemical measurements. When the concentration of the Au solution was decreased, grain size of the polycrystalline hollow Au nanospheres was reduced, and the structures became highly porous. After the Pd shell formed on these Au nanospheres, the morphology and structure of the Au/Pd nanoparticles varied and hence significantly affected the catalytic properties. The Au/Pd nanoparticles synthesized with reduced Au concentrations showed higher formic acid oxidation activity (0.93 mA cm-2 at 0.3 V) than the commercial Pd black (0.85 mA cm-2 at 0.3 V), suggesting a promising candidate as fuel cell catalysts. In addition, the Au/Pd nanoparticles displayed lower CO-stripping potential, improved stability, and higher durability compared to the Pd black due to their unique core-shell structures tuned by Au core morphologies.

  16. L’organizzazione dello spazio e la percezione della paura nelle politiche della sicurezza urbana. Il muro nei processi di inclusione (ed esclusione sociale in Brasile e in Italia / L’organisation de l’espace urbain et la peur du crime dans les politiques de sécurité urbaine. Le mur dans le processus d’inclusion (et d’exclusion sociale au Brésil et en Italie / The organization of urban space and the fear of crime at the level of urban security policies. The wall and the social inclusion (and exclusion processes in Brazil and in Italy

    Directory of Open Access Journals (Sweden)

    Veratti Daniele

    2012-04-01

    Full Text Available In this article, the authors examine the relationship between the wall (real and symbolic and the feeling of urban insecurity.In the course of history, the function of walls was both to protect and to control and segregate.Today, the urban city is a more fluid place, constituted of a network of communications and relationships and devoid of material elements. However, the increase of gated communities represents the return of the concrete wall.In this text, the authors provide some examples of urban and social breakdown regarding some big Brazilian towns. Cet article vise à examiner la relation entre le mur (concret et symbolique et la perception de l'insécurité par les citoyens.Au cours de l'histoire, le mur a eu de nombreuses fonctions : défendre, protéger mais aussi contrôler et séparer.De nos jours, les centres urbains sont constitués par les relations humaines et la communication ; pauvres en éléments concrets, ils sont plus fluides. Néanmoins, la construction d’ensembles résidentiels fermés conduit au retour du mur en béton.Quelques exemples de la désagrégation urbaine et sociale typique des grandes villes brésiliennes seront donnés dans cet article.

  17. Reactivity of Mononuclear and Dinuclear Gold(I Amidinate Complexes with CS2 and CsBr3

    Directory of Open Access Journals (Sweden)

    Andrew C. Lane

    2014-10-01

    Full Text Available To probe the reactivity of gold-nitrogen bonds, we have examined the insertion chemistry with carbon disulfide (CS2 as well as oxidation with cesium tribromide (CsBr3 with Au(I amidinate complexes. The reaction of Ph3PAuCl with Na[(2,6-Me2C6H3N2C(H] yields the mononuclear, two-coordinate gold(I complex, Ph3PAu[κ1-(2,6-Me2C6H3N2C(H], 1. The reactivity of 1 with CS2 produced the mononuclear Au(I compound, Ph3PAu{κ1-S2C[(2,6-Me2C6H3N2C(H]}, 2. In the case of CsBr3 the previously reported dinuclear Au(I complex, Au[(2,6-Me2C6H3N2C(H]2, 3, was isolated with formation of Ph3PBr2. We also compared the reactivity of CS2 and CsBr3 with 3. Carbon disulfide insertion with 3 produces a dimeric product, Aun[CS2(2,6-Me2C6H3NC(H=NC6H3Me2]n, 4, featuring a dinuclear core with linking aurophilic interactions, making it appear polymeric in the solid state. When CsBr3 is reacted with 3 the Au(II,II product is obtained, Au2[(2,6-Me2C6H3N2C(H]2(Br2, 5.

  18. Qualit? de vie et v?cu de la maladie, avant et apr?s hyst?rectomie vaginale, chez les femmes admises au Centre Hospitalier Universitaire de Brazzaville

    OpenAIRE

    Mbongo, Jean Alfred; Mouanga, Alain; Miabaou, Didace Massamba; Nzelie, Aya; Iloki, L?on Herv?

    2016-01-01

    Toute maladie est un mal en soi qu?il faut ?radiquer car elle alt?re souvent de fa?on significative la qualit? de la vie. L?hyst?rectomie vaginale est indiqu?e pour les patientes qui pr?sentent certaines affections gyn?cologiques graves, elle est donc b?n?fique mais, peut ?galement avoir une r?percussion n?faste sur la qualit? de vie de la femme. Ainsi nous avons voulu explorer le v?cu de la maladie et de l?hyst?rectomie vaginale (HV) des femmes avant et apr?s l?intervention chirurgicale. Nou...

  19. Adsorption and dehydrogenation of tetrahydroxybenzene on Cu(111)

    DEFF Research Database (Denmark)

    Bebensee, Fabian; Svane, K.; Bombis, Christian

    2013-01-01

    Adsorption of tetrahydroxybenzene (THB) on Cu(111) and Au(111) surfaces is studied using a combination of STM, XPS, and DFT. THB is deposited intact, but on Cu(111) it undergoes gradual dehydrogenation of the hydroxyl groups as a function of substrate temperature, yielding a pure dihydroxy-benzoq...

  20. Ozone Depletion Potential of CH3Br

    Science.gov (United States)

    Sander, Stanley P.; Ko, Malcolm K. W.; Sze, Nien Dak; Scott, Courtney; Rodriquez, Jose M.; Weisenstein, Debra K.

    1998-01-01

    The ozone depletion potential (ODP) of methyl bromide (CH3Br) can be determined by combining the model-calculated bromine efficiency factor (BEF) for CH3Br and its atmospheric lifetime. This paper examines how changes in several key kinetic data affect BEF. The key reactions highlighted in this study include the reaction of BrO + H02, the absorption cross section of HOBr, the absorption cross section and the photolysis products of BrON02, and the heterogeneous conversion of BrON02 to HOBR and HN03 on aerosol particles. By combining the calculated BEF with the latest estimate of 0.7 year for the atmospheric lifetime of CH3Br, the likely value of ODP for CH3Br is 0.39. The model-calculated concentration of HBr (approximately 0.3 pptv) in the lower stratosphere is substantially smaller than the reported measured value of about I pptv. Recent publications suggested models can reproduce the measured value if one assumes a yield for HBr from the reaction of BrO + OH or from the reaction of BrO + H02. Although the DeAlore et al. evaluation concluded any substantial yield of HBr from BrO + HO2 is unlikely, for completeness, we calculate the effects of these assumed yields on BEF for CH3Br. Our calculations show that the effects are minimal: practically no impact for an assumed 1.3% yield of HBr from BrO + OH and 10% smaller for an assumed 0.6% yield from BrO + H02.

  1. c-Axis correlated extended defects and critical current in YBa{sub 2}Cu{sub 3}O{sub x} films grown on Au and Ag-nano dot decorated substrates

    Energy Technology Data Exchange (ETDEWEB)

    Mikheenko, P., E-mail: p.mikheenko@bham.ac.u [Department of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham, West Midlands B15 2TT (United Kingdom); Sarkar, A.; Dang, V.-S.; Tanner, J.L.; Abell, J.S. [Department of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham, West Midlands B15 2TT (United Kingdom); Crisan, A. [Department of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham, West Midlands B15 2TT (United Kingdom); National Institute of Materials Physics, Bucharest 077125 (Romania)

    2009-07-15

    We report measurements of critical current in YBa{sub 2}Cu{sub 3}O{sub x} films deposited on SrTiO{sub 3} substrates decorated with silver and gold nanodots. An increase in critical current in these films, in comparison with the films deposited on non-decorated substrates, has been achieved. We argue that this increase comes from the c-axis correlated extended defects formed in the films and originated from the nanodots. Additionally to creating extended defects, the nanodots pin them and prevent their exit from the sample during the film growth, thus keeping a high density of defects and providing a lower rate of decrease of the critical current with the thickness of the films. The best pinning is achieved in the samples with silver nanodots by optimising their deposition temperature. The nanodots grown at a temperature of a few hundred deg. C have a small diameter of a few nanometres and a high surface density of 10{sup 11}-10{sup 12} particles/cm{sup 2}. We give evidence of c-axis correlated extended defects in YBa{sub 2}Cu{sub 3}O{sub x} films by planar and cross-sectional atomic force microscopy, transmission electron microscopy and angle-dependent transport measurements of critical current.

  2. Ten metal complexes of vitamin B3/niacin: Spectroscopic, thermal, antibacterial, antifungal, cytotoxicity and antitumor studies of Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Pd(II), Cd(II), Pt(IV) and Au(III) complexes

    Science.gov (United States)

    Al-Saif, Foziah A.; Refat, Moamen S.

    2012-08-01

    Ten coordination compounds, namely Mn(NA)2Cl2·4H2O (1), Fe(NA)Cl3(H2O)2 (2), Co(NA)2(NO3)2·6H2O (3), Ni(NA)Cl2·5H2O (4), Cu(NA)Cl2·3H2O (5), Zn(NA)(NO3)2·H2O (6), Pd(NA)2Cl2·H2O (7), Cd(NA)Cl2·H2O (8), Pt(NA)2Cl4·5H2O (9) and Au(NA)Cl3 (10) were obtained by the reactions of the corresponding transition metal salts with vitamin B3/niacin (NA) in the presence of 1:4 (v:v) distilled water: methanol solvent at 70 °C for about 30 min, and their suggested structures were determined by elemental analyses, molar conductivity, (infrared, UV-vis) spectra, effective magnetic moment in Bohr magnetons, electron spin resonance (ESR), thermal analysis (TG), X-ray powder diffraction (XRD) as well as scanning electron microscopy (SEM). The results revealed that in complexes 1, 3, 7, and 9 both of two NA ligand coordinates one metal ion to form four or six coordinated structures, while in compound 10, one NA ligand coordinate to Au+++ ion to form a square-planar geometry with N-bonded pyridine ligand is suggested, and (2, 4, 5, 6 and, 8) complexes have 1:1 structures. Antimicrobial and antitumor activities were assessment against some kind of (G+ and G-) bacteria, fungi and breast carcinoma cells (MCF-7-cell line).

  3. On the stability of copper overlayers on Au(1 1 1) and Au(1 0 0) electrodes under low potential conditions and in the presence on CO and CO2

    Science.gov (United States)

    Schlaup, Christian; Horch, Sebastian; Chorkendorff, Ib

    2015-01-01

    We have studied the stability of Cu overlayers on Au(1 1 1) and Au(1 0 0) electrodes under low potential conditions and in the presence of CO and CO2 by means of electrochemical STM (EC-STM). For preparation we utilized the well known underpotential deposition (UPD) of copper, which, depending on the electrolyte (HClO4 and H2SO4), leads to Cu coverages in the submonolayer to monolayer range. For a Cu submonolayer on Au(1 1 1) we found that independent from the actual gas coadsorbate its closed film-like structure collapses at low potentials due to the desorption of coadsorbed anions. In contrast we found for a full Cu monolayer on Au(1 1 1) and Au(1 0 0) the formation of an alloy phase under low potential conditions, which also occurs independent from the presence of gas coadsorbates.

  4. Operations and Performance of RHIC as a Cu-Cu Collider

    CERN Document Server

    Pilat, Fulvia Caterina; Bai, Mei; Barton, Donald; Beebe-Wang, Joanne; Blaskiewicz, Michael; Brennan, Joseph M; Bruno, Donald; Cameron, Peter; Connolly, Roger; De Long, Joseph; Drees, Angelika; Fischer, Wolfram; Ganetis, George; Gardner, Chris J; Glenn, Joseph; Harvey, Margaret; Hayes, Thomas; Hseuh Hsiao Chaun; Huang, Haixin; Ingrassia, Peter; Iriso, Ubaldo; Lee, Roger C; Litvinenko, Vladimir N; Luo, Yun; MacKay, William W; Marr, Gregory J; Marusic, Al; Michnoff, Robert; Montag, Christoph; Morris, John; Nicoletti, Tony; Oerter, Brian; Ptitsyn, Vadim; Roser, Thomas; Russo, Thomas; Sandberg, Jon; Satogata, Todd; Schultheiss, Carl; Tepikian, Steven; Tomas, Rogelio; Trbojevic, Dejan; Tsoupas, Nicholaos; Tuozzolo, Joseph; Vetter, Kurt; Zaltsman, Alex; Zeno, Keith; Zhang, S Y; Zhang, Wu

    2005-01-01

    The 5th year of RHIC operations, started in November 2004 and expected to last till June 2005, consists of a physics run with Cu-Cu collisions at 100 GeV/u followed by one with polarized protons at 100 GeV. We will address here overall performance of the RHIC complex used for the first time as a Cu-Cu collider, and compare it with previous operational experience with Au, PP and asymmetric d-Au collisions. We will also discuss operational improvements, such as a ?* squeeze to 85cm in the high luminosity interaction regions from the design value of 1m, system improvements and machine performance limitations, such as vacuum pressure rise, intra-beam scattering, and beam beam interaction.

  5. OPERATIONS AND PERFORMANCE OF RHIC AS A CU-CU COLLIDER.

    Energy Technology Data Exchange (ETDEWEB)

    PILAT, R.; AHRENS, L.; BAI, M.; BARTON, D.S.; ET AL.

    2005-05-16

    The 5th year of RHIC operations, started in November 2004 and expected to last till June 2005, consists of a physics run with Cu-Cu collisions at 100 GeV/u followed by one with polarized protons (pp) at 100 GeV [l]. We will address here the overall performance of the RHIC complex used for the first time as a Cu-Cu collider, and compare it with previous operational experience with Au, PP and asymmetric d-Au collisions. We will also discuss operational improvements, such as a {beta}* squeeze to 85cm in the high luminosity interaction regions from the design value of 1m, system improvements, machine performance and limitations, and address reliability and uptime issues.

  6. Brésil | CRDI - Centre de recherches pour le développement ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les recherches subventionnées par le CRDI au Brésil ont permis d'éclairer les débats sur nombre de questions, dont la démocratie, la croissance économique, la santé, les services sociaux, l'innovation, la foresterie et l'eau. Pendant la dictature militaire, qui a pris fin en 1985, le CRDI s'est employé à assurer la survie de la ...

  7. Atmospheric fate of CF sub 3 Br, CF sub 2 Br sub 2 , CF sub 2 ClBr, and CF sub 2 BrCF sub 2 Br

    Energy Technology Data Exchange (ETDEWEB)

    Burkholder, J.B.; Wilson, R.R.; Gierczak, T.; Talukdar, R.; McKeen, S.A.; Orlando, J.J.; Vaghjiani, G.L.; Ravishankara, A.R. (National Oceanic and Atmospheric Administration, Boulder, CO (USA) Univ. of Colorado, Boulder (USA))

    1991-03-20

    The temperature dependent UV absorption cross sections of the haloalkanes CF{sub 3}Br, CF{sub 2}ClBr, CF{sub 2}Br{sub 2}, and CF{sub 2}BrCF{sub 2} are reported. The UV absorption cross sections were measured over the temperature range 210 to 296 K and the wavelength range 190 to 320 nm. Upper limits of the rate coefficients for the reactions of OH with CF{sub 3}Br, CF{sub 2}Br{sub 2}, CF{sub 2}ClBr, and CF{sub 2}BrCF{sub 2}Br were also determined using both pulsed photolysis and flow tube techniques. The rate coefficients at 296 K were found to be <1.2 {times} 10{sup {minus}16}, <1.5 {times} 10{sup {minus}16}, <5.0 {times} 10{sup {minus}16}, and <1.5 {times} 10{sup {minus}16} cm{sup 3} molec{sup {minus}1} s{sup {minus}1} for CF{sub 3}Br, CF{sub 2}ClBr, CF{sub 2}BrCF{sub 2}Br, respectively. The UV absorption cross-section data and OH reaction rate coefficients of these species were combined with a one-dimensional model to yield atmospheric lifetimes of 65, 16, 3.2, and <20 years for CF{sub 3}Br, CF{sub 2}ClBr, CF{sub 2}Br{sub 2}, and CF{sub 2}BrCF{sub 2}Br, respectively.

  8. Seropositivite au vih et grossesse au Togo: vecu et representation a ...

    African Journals Online (AJOL)

    Introduction : Ce travail avait pour objectifs d'identifier les indicateurs de la représentation et du vécu des femmes enceintes séropositives d'une part, et de rechercher un lien entre ces indicateurs chez ces femmes au sud du Togo. Méthodologie : Le cadre de notre étude ont été l'hôpital de Bè, le centre de santé de Lomé, ...

  9. Ustioni da fuoco / Burn injuries / Les brûlures

    Directory of Open Access Journals (Sweden)

    Liliana Copertino

    2008-04-01

    Full Text Available Severe burn injuries require high specialistic treatment. Burn injuries are common in disasters and war scenarios, so war medicine has been fundamental to improve treatment protocols for burn patients..Burn injuries are classified according to the etiopathogenetic agent (physical, chemical or radiation, that determines different anatomoisthologic aspects.An estimation of the depth and extension are fundamental for defining the gravity of the burn. Critical burn patients have to be transported in specialistic Centers. There they are treated by multispecialistic teams from the resuscitation phase to the reconstructive surgery and specialist rehabilitation.. This process can continue for two years with the objective to return patients to a quiet normal life. Les brûlures sont des lésions traumatiques qui requièrent un traitement spécialisé. Lors de catastrophes et de guerres, les brûlures sont des lésions très fréquentes et la médecine de guerre a contribué à faire avancer la science de manière importante, dans le traitement de cette pathologie.Les brûlures sont classées en fonction de l'agent étiopathogénique (agents physiques, chimiques ou radiations dont le mécanisme d'action qui provoque la lésion cause des aspects anatomohistologiques caractéristiques.Pour définir la sévérité d'une brûlure, il est aussi fondamental d'éstimer l'extension de la surface corporelle et la profondeur de l'épiderme, et éventuellement du derme, atteints. Les patients gravement brûlés doivent être hospitalisés dans des Centres Spécialisés où des équipes multispécialistes les suivent de la phase initiale de la réanimation aux phases de chirurgie reconstructive et au processus de réhabilitation. Ces dernières phases peuvent se prolonger pendant les deux années suivant le traumatisme avant qu'une réintégration dans une vie sociale acceptable ne puisse être faite.

  10. Biblioteca lui Constantin Brâncoveanu de la Hurez în lumina a 300 de ani de la trecerea în nefiinţă a sa

    Directory of Open Access Journals (Sweden)

    Agnes Erich

    2014-01-01

    Full Text Available Bibliotecile care au funcţionat de-a lungul timpului în palatele voievodale, casele boiereşti, şcoli şi mănăstiri au păstrat dovezi scrise de necontestat despre îndeletnicirile intelectuale ale domnitorilor români. Astfel, pasiunea pentru carte, trecută de la generaţie la generaţie în familia Cantacuzinilor, s-a concretizat şi în preocupările spirituale ale lui Constantin Brâncoveanu care va fi crescut de mama sa, Stanca Cantacuzino, fiica postelnicului, şi de unchiul său, stolnicul Constantin Cantacuzino. Deci, va creşte şi se va forma în casele cantacuzineşti de la Filipeşti (Mărgineni şi Bucureşti, unde va fi aflat mari şi preţioase colecţii de cărţi provenind din spaţiul europen. Astfel se explică înfiinţarea Bibliotecii de la Hurez, în aşezământul monahal cu acelaşi nume.

  11. Dissolution de phases minérales MSiO3 ( M Cu, Co, Ni, Zn, Mg) imparfaitement cristallisées au contact de solutions d'agents complexants organiques (porphyrines, amino-acides, asphaltènes)

    Science.gov (United States)

    Bergaya, F.; Perruchot, A.; Van Damme, H.

    1983-05-01

    The kinetic and thermodynamic aspects of the dissolution of ill-organized ("gels") high surface area silicates of general formula MO- SiO2- nH2O( M = Cu, Co, Ni, Zn, Mg) in the presence of the following organic compounds have been investigated: meso-tetraphenylporphyrin (H 2TPP, water insoluble), mesotetra(N-methylpyridyl)porphyrin (H 3TMPyP, water soluble), glycine, and asphaltenes. Kinetic aspects were emphasised in the case of H 2TMPyP. The initial rate of the gross dissolution complexation process followed almost quantitatively (passing from one metal to another) the complexation rate of M2+ ions by H 2TMPyP in a purely homogeneous medium, suggesting that the rate limiting step of the overall process is not related to the chemical or physical processes occurring in the solid particles or at the solid-solution interface, but is simply the complexation, in the solution, of the M2+ ions released by the gel particles. Thermodynamic aspects were emphasised in the case of glycine. The total amount of metal which is extracted at equilibrium can be reasonably well predicted from a simple model which takes into account (i) the stability constant of the metal-glycine complex. (ii) the "solubility product" of the gel particles in water. The results obtained with asphaltones are closer to those obtained with glycine than to those obtained with porphyrins, suggesting that porphyrins represent only a minor population in the complexing functional groups of asphaltenes.

  12. Cd4As2Br3

    Directory of Open Access Journals (Sweden)

    Mohammed Kars

    2014-03-01

    Full Text Available Single crystals of Cd4As2Br3 (tetracadmium biarsenide tribromide were grown by a chemical transport reaction. The structure is isotypic with the members of the cadmium and mercury pnictidohalides family with general formula M4A2X3 (M = Cd, Hg; A = P, As, Sb; X = Cl, Br, I and contains two independent As atoms on special positions with site symmetry -3 and two independent Cd atoms, of which one is on a special position with site symmetry -3. The Cd4As2Br3 structure consists of AsCd4 tetrahedra sharing vertices with isolated As2Cd6 octahedra that contain As–As dumbbells in the centre of the octahedron. The Br atoms are located in the voids of this three-dimensional arrangement and bridge the different polyhedra through Cd...Br contacts.

  13. Dynamics of copper-phthalocyanine molecules on Au/Ge(001)

    NARCIS (Netherlands)

    Sotthewes, Kai; Heimbuch, Rene; Zandvliet, Henricus J.W.

    2015-01-01

    Spatially resolved current-time scanning tunneling spectroscopy combined with current-distance spectroscopy has been used to characterize the dynamic behavior of copper-phthalocyanine (CuPc) molecules adsorbed on a Au-modified Ge(001) surface. The analyzed CuPc molecules are adsorbed in a “molecular

  14. Binary molecular layers of C-60 and copper phthalocyanine on Au(111) : Self-organized nanostructuring

    NARCIS (Netherlands)

    Stöhr, Meike; Wagner, Thorsten; Gabriel, Markus; Weyers, Bastian; Möller, Rolf

    The binary molecular system of C-60 and copper phthalocyanine(CuPc) molecules has been investigated by scanning tunneling microscopy (STM) at room temperature and at 50 K. As substrate Au(111) was chosen. When C-60 and CuPc molecules are sequentially deposited, it is found that well-ordered domains

  15. Electronic structure of square planar bis(benzene-1,2-dithiolato)metal complexes [M(L)(2)](z) (z = 2-, 1-, 0; M = Ni, Pd, Pt, Cu, Au): an experimental, density functional, and correlated ab initio study.

    Science.gov (United States)

    Ray, Kallol; Weyhermüller, Thomas; Neese, Frank; Wieghardt, Karl

    2005-07-25

    The three diamagnetic square planar complexes of nickel(II), palladium(II), and platinum(II) containing two S,S-coordinated 3,5-di-tert-butylbenzene-1,2-dithiolate ligands, (L(Bu))(2-), namely [M(II)(L(Bu))(2)](2-), have been synthesized. The corresponding paramagnetic monoanions [M(II)(L(Bu))(L(Bu)(*))](-) (S = (1)/(2)) and the neutral diamagnetic species [M(II)(L(Bu)(*))(2)] (M = Ni, Pd, Pt) have also been generated in solution or in the solid state as [N(n-Bu)(4)][M(II)(L(Bu))(L(Bu)(*))] salts. The corresponding complex [Cu(III)(L(Bu))(2)](-) has also been investigated. The complexes have been studied by UV-vis, IR, and EPR spectroscopy and by X-ray crystallography; their electro- and magnetochemistry is reported. The electron-transfer series [M(L(Bu))(2)](2-,-,0) is shown to be ligand based involving formally one (L(Bu)(*))(-) pi radical in the monoanion or two in the neutral species [M(II)(L(Bu)(*))(2)] (M = Ni, Pd, Pt). Geometry optimizations using all-electron density functional theory with scalar relativistic corrections at the second-order Douglas-Kroll-Hess (DKH2) and zeroth-order regular approximation (ZORA) levels result in excellent agreement with the experimentally determined structures and electronic spectra. For the three neutral species a detailed analysis of the orbital structures reveals that the species may best be described as containing two strongly antiferromagnetically interacting ligand radicals. Furthermore, multiconfigurational ab initio calculations using the spectroscopy oriented configuration interaction (SORCI) approach including the ZORA correction were carried out. The calculations predict the position of the intervalence charge-transfer band well. Chemical trends in the diradical characters deduced from the multiconfigurational singlet ground-state wave function along a series of metals and ligands were discussed.

  16. buFacile synthesis and characterization of CsPbBr3 and CsPb2Br5 ...

    Indian Academy of Sciences (India)

    65

    CsPb2Br5 powders show a white color. Based on the results of the XRD analysis, it can be seen that the Cs+/Pb2+ mole ratio has the effect on the phase of final product in this synthesis process. Generally speaking, there is a reaction occurring for the formation of CsPbBr3 by CsBr and. PbBr2: CsBr + PbBr2 → CsPbBr3. (1).

  17. Neutron diffraction study of La 4LiAuO 8: Understanding Au 3+ in an oxide environment

    Science.gov (United States)

    Kurzman, Joshua A.; Moffitt, Stephanie L.; Llobet, Anna; Seshadri, Ram

    2011-06-01

    Owing to gold's oxophobicity, its oxide chemistry is rather limited, and elevated oxygen pressures are usually required to prepare ternary and quaternary oxide compounds with gold ions. The Au 3+ oxide, La 4LiAuO 8, is remarkable both because it can be prepared at ambient pressure in air, and because of its unusual stability toward thermal decomposition and reduction. The structure of La 4LiAuO 8 was established by Pietzuch et al. using single crystal X-ray diffraction [1]. The compound adopts an ordered modification of the Nd 2CuO 4 structure, containing two-dimensional sheets in which AuO 4 square planes are separated from one another by LiO 4 square planes. In light of the meager X-ray scattering factors of Li and O, relative to La and Au, we report here a neutron powder diffraction study of La 4LiAuO 8, definitively confirming the structure. To our knowledge, this is the first reported neutron diffraction study of any stoichiometric oxide compound of gold. X- N maps, which make use of nuclear positions obtained from Rietveld refinement of time-of-flight neutron diffraction data and electron densities obtained from synchrotron X-ray powder diffraction data, point to the highly covalent nature of the Au-O bonding in La 4LiAuO 8. This is in good agreement with charge densities and Bader charges obtained from full density functional relaxation of the structure.

  18. Lead Telluride Doped with Au as a Very Promising Material for Thermoelectric Applications

    Directory of Open Access Journals (Sweden)

    Pantelija M. Nikolic

    2015-01-01

    Full Text Available PbTe single crystals doped with monovalent Au or Cu were grown using the Bridgman method. Far infrared reflectivity spectra were measured at room temperature for all samples and plasma minima were registered. These experimental spectra were numerically analyzed and optical parameters were calculated. All the samples of PbTe doped with Au or Cu were of the “n” type. The properties of these compositions were analyzed and compared with PbTe containing other dopants. The samples of PbTe doped with only 3.3 at% Au were the best among the PbTe + Au samples having the lowest plasma frequency and the highest mobility of free carriers-electrons, while PbTe doped with Cu was the opposite. Samples with the lowest Cu concentration of 0.23 at% Cu had the best properties. Thermal diffusivity and electronic transport properties of the same PbTe doped samples were also investigated using a photoacoustic (PA method with the transmission detection configuration. The results obtained with the far infrared and photoacoustic characterization of PbTe doped samples were compared and discussed. Both methods confirmed that when PbTe was doped with 3.3 at% Au, thermoelectric and electrical properties of this doped semiconductor were both significantly improved, so Au as a dopant in PbTe could be used as a new high quality thermoelectric material.

  19. Hausse des taxes sur le tabac et politiques de lutte antitabac au ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Hausse des taxes sur le tabac et politiques de lutte antitabac au Brésil, au Mexique et en Uruguay. Dans de nombreux pays d'Amérique latine, les taux de tabagisme sont élevés chez les garçons, les filles, les hommes et les femmes. Toutefois, la recherche ne s'est pas encore penchée sur les différences entre les taux de ...

  20. Ionothermal synthesis and structural characterization of [Cu ...

    Indian Academy of Sciences (India)

    an oven. The reaction was carried out at 110◦C for 24 h to afford dark blue crystals of Cu(C4H6N2)4Br2 (1) in about 40.7% yield. Pure crystals were obtained by ..... 1006606 for 1 and 1006607 for 2, and is freely avail- able upon request from the following web site: www. ccdc.cam.ac.Uk/data_request/cif. The ORTEP view of.

  1. La comparaison en géographie. Contribution à partir de l'étude de la coopération intercommunale en France et au Brésil. A comparação em Geografia: uma contribuição a partir do estudo das práticas de cooperação intermunicipal na França e no Brasil. Comparative Geography: a contribution from the study of practices of inter-municipal cooperation used in France and in Brazil

    Directory of Open Access Journals (Sweden)

    Juliana Nunes Rodrigues

    2012-11-01

    Full Text Available Ce texte porte sur les processus de coopération intercommunale qui se développe en France et au Brésil. Il prend appui sur des enquêtes de terrain en France (région Rhône-Alpes et au Brésil (État de Rio de Janeiro. Il interroge dans les deux cas l’influence des armatures institutionnelles de l’État français et de l’État brésilien pour comprendre les particularités de la pratique coopérative entre communes dans ces deux pays. L’objectif est de valoriser la méthode comparative dans le débat concernant le renforcement des échelons locaux de gestion et les manières différentes de concevoir la coopération intercommunale dans deux modèles d’État fort différents.Este texto aborda um conjunto de problemáticas que se referem às práticas de cooperação intermunicipal que se desenvolvem na França e no Brasil. Por um lado, trata-se de retomar algumas conclusões de trabalhos de campo realizados na Região Rhône-Alpes, na França, e no Estado federal do Rio de Janeiro, no Brasil. Por outro lado, são discutidas questões relacionadas aos aparatos institucionais do Estado francês e do Estado brasileiro, e a maneira como influenciam a concepção, o formato e o funcionamento das estruturas de cooperação intermunicipal nos dois países. O objetivo é valorizar o método comparativo em um debate acerca dos desdobramentos espaciais da cooperação intermunicipal e da valorização das escalas de gestão local em dois modelos de Estado diferentes.This text discusses a set of issues concerning the processes of inter-municipal cooperation developing in France and in Brazil. On the one hand, it brings back some conclusions explored during the realization of surveys made in the region of Rhône-Alpes, in France, and in the state of Rio de Janeiro, Brazil. On the other hand, it examines the influence of the organization of the French and Brazilian States in order to comprehend the particularities of cooperative practices

  2. AU BURKINA FASO

    African Journals Online (AJOL)

    Les moyennes sur la même ligne et possédant le même indice ne diffèrent pas significativement au seuil de 5 %. ME : mélange fourrager. 10-20-30 % : pourcentage de concentré. GMQ : Gain Moyen Quotidien. L'analyse des résultats des rations. 1 et 2 montre que l'accès au pâturage permet des performances supérieures.

  3. A GREEN CHEMISTRY APPROACH TO PREPARATION OF CORE (FE OR CU)-SHELL (NOBLE METALS) NANOCOMPOSITES USING AQUEOUS ASCORBIC ACID

    Science.gov (United States)

    A greener method to fabricate novel core (Fe or Cu)-shell (noble metals) nanocomposites of transition metals such as Fe and Cu and noble metals such as Au, Pt, Pd, and Ag using aqueous ascorbic acid is described. Transition metal salts such as Cu and Fe were reduced using ascor...

  4. On the stability of copper overlayers on Au(1 1 1) and Au(1 0 0) electrodes under low potential conditions and in the presence on CO and CO2

    DEFF Research Database (Denmark)

    Schlaup, Christian Georg; Horch, Sebastian; Chorkendorff, Ib

    2015-01-01

    We have studied the stability of Cu overlayers on Au(1 1 1) and Au(1 0 0) electrodes under low potential conditions and in the presence of CO and CO2 by means of electrochemical STM (EC-STM). For preparation we utilized the well known underpotential deposition (UPD) of copper, which, depending...

  5. Role of halogen atoms in the formation of one-dimensional Cu(I) coordination polymers based on 2-amino-5-halopyrimidine

    Science.gov (United States)

    Chhetri, Pradhumna Mahat; Chang, Yu-Chia; Hu, Hui-Ling; Chiang, Yen-Hsun; Yang, Xiang-Kai; Chen, Jhy-Der

    2017-09-01

    The reactions of CuCl and CuBr with 2-amino-5-chloropyrimidine (L-Cl), 2-amino-5-bromopyrimidine (L-Br) and 2-amino-5-iodopyrimidine (L-I) in aqueous solutions of HCl and HBr afforded [CuCl2(HL-I) · H2O]n, 1, [CuBr2(HL-I) · H2O]n, 2, [CuCl2(HL-Br) · H2O]n, 3, [CuBr2(HL-Br) · H2O]n, 4, and [CuCl2(HL-Cl) · H2O)n, 5. Complexes 1-5 show 1D zigzag chains due to the zigzag arrangements of the bridging halide atoms. While the iodo atoms of the pyrimidyl rings in 1 and 2 are trans to the bridging halide anions and the Cu(I) ions are in a linear array, the chloro and bromo atoms of the pyrimidyl rings in 3-5 are cis to the bridging halide anions and the Cu(I) ions are in a zigzag fashion. The structural difference can most probably be ascribed to the identity of the halogen atoms. While the chloro and bromo atoms play the same role in the crystal structures, the iodo atom is distinct. X-ray crystallographic study and Hirshfeld surface analysis are invoked to investigate the structural differences.

  6. Cooperative effects of noncovalent bonds to the Br atom of halogen-bonded H3N...BrZ and HCN...BrZ (Z = F, Br) complexes.

    Science.gov (United States)

    McDowell, Sean A C; Joseph, Jerelle A

    2012-08-21

    A series of complexes formed between halogen-bonded H(3)N/HCN...BrZ (Z = Br, F) dimers and H(3)N/HCN...BrZ...XY (XY = HF, ClF, BeH(2), LiF) trimers were investigated at the MP2 and B3LYP levels of theory using a 6-31++G(d,p) basis set. Optimized structures, interaction energies, and other properties of interest were obtained. The addition of XY to the H(3)N/HCN...BrZ dyad leads to enhanced intermolecular binding with respect to the isolated monomers. This enhanced binding receives contributions from the electrostatic and inductive forces between the constituent pairs, with, in some instances, substantial three-body non-additive contributions to the binding energy. It was found that the XY = LiF interaction causes the greatest distortion of the H(3)N/HCN...BrZ halogen bond from the preferred linear orientation and also provides the strongest binding energy via the nonadditive energy.

  7. Systematic hardness measurements on CsClxBr (and NH4ClxBr ...

    Indian Academy of Sciences (India)

    ... Lecture Workshops · Refresher Courses · Symposia. Home; Journals; Bulletin of Materials Science; Volume 25; Issue 1. Systematic hardness measurements on CsClBr(1–x) and NH4ClBr(1–x) mixed crystals. K G Subhadra E Balaiah D B Sirdeshmukh. Mechanical Properties Volume 25 Issue 1 February 2002 pp 31- ...

  8. Effects of Cu{sup 2+} on aggregation behavior of poly (l-Glutamic Acid)-functionalized gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    He Ke; Li Jun; Ni Yuyang; Fu Rao; Huang Zhenzhen; Yang Wensheng, E-mail: wsyang@jlu.edu.cn [Jilin University, State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry (China)

    2013-01-15

    The effect of Cu{sup 2+} ions on aggregation behaviors of poly (l-glutamic acid) (PLGA)-functionalized Au nanoparticles was investigated. It was found that the concentration of Cu{sup 2+} ions had a significant influence on the folding and the formation of intermolecular hydrogen bonding of PLGA and thus the aggregation of the Au nanoparticles. In the absence of Cu{sup 2+} ions, the Au nanoparticles underwent reversible pH-dependent aggregation attributed to the folding/unfolding of PLGA and the formation/breakage of intermolecular hydrogen bonds between PLGA molecules. In the presence of low concentration of Cu{sup 2+} ions (i.e., 10 {mu}M), folding of PLGA and aggregation of the Au nanoparticles were facilitated due to the charge screening effect of Cu{sup 2+} ions, while the reversibility was partly maintained. In the presence of high concentration of Cu{sup 2+} ions (i.e., 50 {mu}M), aggregation of the Au nanoparticles was dominated by the coordination interaction between PLGA and Cu{sup 2+} ions and the aggregation became irreversible due to the blocking of the formation of intermolecular hydrogen bonds by Cu{sup 2+}. These results suggested that Au nanoparticles may be used as a colorimetric probe to monitor the interactions between metal ions and peptides, which are essential for exploring the physiological effect of metals ions.

  9. 11 juillet 2014 - Y. Bréchet Haut-Commissaire à l’énergie atomique et aux énergies alternatives (CEA) en France

    CERN Document Server

    Barnard, Henry

    2014-01-01

    Monsieur Yves Bréchet en visite dans le tunnel du LHC au Point 5 ainsi que la caverne expérimentale de CMS avec T. Camporesi, Porte-parole de la Collaboration CMS. Signature du livre d'or avec F. Bordry, Directeur des accélérateurs et de la technologie.

  10. Reaction of atomic bromine with acetylene and loss rate of atmospheric acetylene due to reaction with OH, Cl, O, and Br

    Science.gov (United States)

    Payne, W. A.; Nava, D. F.; Brunning, J.; Stief, L. J.

    1986-01-01

    The first-order, diffusion, and bimolecular rate constants for the reaction Br + C2H2 yields C2H3Br are evaluated. The rate constants are measured at 210, 248, 298, and 393 K and at pressures between 15-100 torr Ar using flash photolysis combined with time-resolved detection of atomic bromine via Br resonance radiation. It is observed that the reaction is not affected by pressure or temperature and the bimolecular constant = (4.0 + or - 0.8) x 10 to the -15th cu cm/sec with an error of two standard deviations. The C2H2 + Br reaction rates are compared with reactions of C2H2 with Cl, OH, NH2, and H. The loss rates for atmospheric C2H2 for reactions with OH, Cl, O, and Br are calculated as a function of altitude.

  11. Institut brésilien pour la recherche écologique : L'enseignement et l ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    En faisant un retour sur son expérience au FIE 2008, la Dre Suzana Padua, présidente de l'Institut pour la recherche écologique (IPE) du Brésil a déclaré ce qui suit : « Quand on comprend plus l'interconnexion de tout ce qui vit sur la planète, on ne pas faire autrement que d'être touchée d'une certaine façon », a dit la Dre ...

  12. The role of Br2 and BrCl in surface ozone destruction at polar sunrise.

    Science.gov (United States)

    Foster, K L; Plastridge, R A; Bottenheim, J W; Shepson, P B; Finlayson-Pitts, B J; Spicer, C W

    2001-01-19

    Bromine atoms are believed to play a central role in the depletion of surface-level ozone in the Arctic at polar sunrise. Br2, BrCl, and HOBr have been hypothesized as bromine atom precursors, and there is evidence for chlorine atom precursors as well, but these species have not been measured directly. We report here measurements of Br2, BrCl, and Cl2 made using atmospheric pressure chemical ionization-mass spectrometry at Alert, Nunavut, Canada. In addition to Br2 at mixing ratios up to approximately 25 parts per trillion, BrCl was found at levels as high as approximately 35 parts per trillion. Molecular chlorine was not observed, implying that BrCl is the dominant source of chlorine atoms during polar sunrise, consistent with recent modeling studies. Similar formation of bromine compounds and tropospheric ozone destruction may also occur at mid-latitudes but may not be as apparent owing to more efficient mixing in the boundary layer.

  13. Au pair trajectories

    DEFF Research Database (Denmark)

    Dalgas, Karina Märcher

    2015-01-01

    Since 2000, thousands of young Filipino migrants have come to Denmark as au pairs. Officially, they are there to “broaden their cultural horizons” by living temporarily with a Danish host family, but they also conduct domestic labor in exchange for food and money, which allows them to send...

  14. Catalytic behavior of Cu, Ag and Au nanoparticles. A comparison

    NARCIS (Netherlands)

    Lippits, Meindert Jan

    2010-01-01

    Clearly gold deposited as nanoparticles on a support is a very active catalyst in contrast to bulk gold which does not show any catalytic activity. The question arises if this particle size effect is exclusively valid for gold catalysis or can a similar effect be found in other metals? In the

  15. Catalytic activity of Au nanoparticles

    DEFF Research Database (Denmark)

    Larsen, Britt Hvolbæk; Janssens, Ton V.W.; Clausen, Bjerne

    2007-01-01

    Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change with par......Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change...... with particle size. We find that the fraction of low-coordinated Au atoms scales approximately with the catalytic activity, suggesting that atoms on the corners and edges of Au nanoparticles are the active sites. This effect is explained using density functional calculations....

  16. Effects of Au nanoparticle addition to hole transfer layer in organic solar cells based on copper naphthalocyanine and fullerene

    Directory of Open Access Journals (Sweden)

    Akihiko Nagata

    2014-06-01

    Full Text Available Organic solar cells based on copper naphthalocyanine (CuNc and fullerene (C60 were fabricated, and their photovoltaic properties were investigated. C60 and CuNc were used as n-type and p-type semiconductors, respectively. In addition, the effect of Au nanoparticle addition on a hole transfer layer was investigated, and the power conversion efficiency of the devices was improved after blending the Au nanoparticles into the hole transport layer. Nanostructures of Au nanoparticles were investigated by transmission electron microscopy and X-ray diffraction. Energy levels of molecules were calculated by molecular orbital calculations, and the nanostructure and electronic properties were discussed.

  17. Impact of surface roughness of Au core in Au/Pd core-shell nanoparticles toward formic acid oxidation - Experiment and simulation

    Science.gov (United States)

    Hsu, Chiajen; Huang, Chienwen; Hao, Yaowu; Liu, Fuqiang

    2013-12-01

    The Au/Pd core-shell nanoparticles (NPs) were synthesized via galvanic replacement of Cu by Pd on hollow Au cores by adding different concentrations of Na2SO3 solution. It was found that the higher concentration of Na2SO3 that was used, the rougher the Au nanospheres became. However, the rougher Au surface may cause more defects in the Pd layers and decrease the catalytic abilities. The Au/Pd NPs synthesized using 0 M Na2SO3 (denoted as 0 M-Au/Pd NPs) have the smoothest Pd surface and demonstrate higher formic acid oxidation (FAO) activity (0.714 mA cm-2, normalized to the surface area of Pd) than other Au/Pd NPs and commercial Pd black (0.47 mA cm-2). Additional electrochemical characterization of the 0 M-Au/Pd NPs also demonstrated lower CO-stripping onset and peak potentials, higher stability (8× improvement in stabilized oxidation current), and superior durability (by 1.6×) than the Pd black. In addition, a simple simulation of FAO was adopted to predict the anodic curve by including reaction intermediates of formate and hydroxyl. The 0 M-Au/Pd NPs were found to show higher formate and lower hydroxyl coverage than the Pd black.

  18. Ce{sub 2}PdIn{sub 8}, Ce{sub 3}PdIn{sub 11} and Ce{sub 5}Pd{sub 2}In{sub 19}—members of homological series based on AuCu{sub 3}- and PtHg{sub 2}-type structural units

    Energy Technology Data Exchange (ETDEWEB)

    Tursina, A.; Nesterenko, S.; Seropegin, Y. [Department of Chemistry, Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Noël, H. [Laboratoire de Chimie du Solide et Matériaux, UMR6226 CNRS-Université de Rennes 1, Avenue du Général Leclerc, Rennes 30542 (France); Kaczorowski, D., E-mail: D.Kaczorowski@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O.Box 1410, Wrocław 50-950 (Poland)

    2013-04-15

    Crystal structures of three members of a unique homological series with the general formula Ce{sub m}Pd{sub n}In{sub 3m+2n} based on the AuCu{sub 3} and PtHg{sub 2} structure types were studied by single-crystal X-ray diffraction. The compounds crystallize with space group P4/mmm (Z=1) and the lattice parameters: a=4.6900(9) Å, c=12.185(6) Å for Ce{sub 2}PdIn{sub 8}, a=4.6846(8) Å, c=16.846(8) Å for Ce{sub 3}PdIn{sub 11}, and a=4.70120(10) Å, c=29.1359(4) Å for Ce{sub 5}Pd{sub 2}In{sub 19}. The crystal structures of Ce{sub 3}PdIn{sub 11} and Ce{sub 5}Pd{sub 2}In{sub 19} represent new types. The three structures constitute of [CeIn{sub 3}] cuboctahedra layers and [PdIn{sub 2}] rectangular polyhedra layers, alternating along the tetragonal c-axis in accordance with the m:n proportion. The magnetic and electrical transport properties of the novel compounds Ce{sub 3}PdIn{sub 11} and Ce{sub 5}Pd{sub 2}In{sub 19} were investigated down to 1.72 K. Both indides are Curie–Weiss paramagnets due to the presence of fairly well localized 4f electrons of trivalent cerium ions. The electrical resistivity of both materials is dominated over an extended temperature range by strong spin–flip Kondo interactions with the characteristic temperature scale of 20–30 K. - Graphical abstract: TOC Figure Crystal structures of Ce{sub 3}PdIn{sub 11}, Ce{sub 2}PdIn{sub 8}, and Ce{sub 5}Pd{sub 2}In{sub 19}. Highlights: ► Large section of Ce–Pd–In phase diagram was examined. ► Three distinct ternary phases were identified, two of them for the first time. ► Crystal structures of two novel compounds constitute new structure types. ► The determined crystal structures show close mutual relationship. ► Ce{sub 3}PdIn{sub 11} and Ce{sub 5}Pd{sub 2}In{sub 19} are paramagnetic Kondo lattices.

  19. Transition metal complexes with thiosemicarbazide-based ligands. Part 60. Reactions of copper(II) bromide with pyridoxal S-methylisothiosemicarbazone (PLITSC). Crystal structure of [Cu(PLITSC−H)H2O]Br•H2O

    OpenAIRE

    Leovac Vukadin M.; Vojinović-Ješić Ljiljana S.; Ivković Sonja A.; Rodić Marko V.; Jovanović Ljiljana S.; Holló Berta; Mészáros-Szécsényi Katalin

    2014-01-01

    The synthesis and structural characterization of a square-planar copper(II) complex with pyridoxal S-methylisothiosemicarbazone (PLITSC) of the formula [Cu(PLITSC−H)H2O]Br•H2O (1) as the first Cu(II) complex with monoanionic form of this ligand were described. Complex 1 together with two previously synthesized complexes [Cu(PLITSC)Br2] (2) and [Cu(PLITSC)Br(MeOH)]Br (3) were characterized by elemental analysis, IR and electronic spectra and also by the meth...

  20. On forge des partenariats au Brésil | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les partenariats assurent le dialogue entre les disciplines et aident à mettre en valeur des interfaces comme les questions de santé animale et de santé publique. Les partenariats soulignent la ... International Association for Ecology and Health—Cultivating Partnerships and Engaging Members. Dr Peter Daszak and Dr ...

  1. Ex-tuyauteur au CERN, il a eu le coeur brûlé

    CERN Multimedia

    Marendaz, Emmanuelle

    2002-01-01

    Georges Settimo worked at CERN in 1974 as a temporary worker and thinks that, working without any protection and manipulating tins with radioactive matter, his illness is not a pure accident. He never spoke in the past because he didn't seek revenge but after the deaths of two of his colleauges who also worked under the laboratory, he wants to make people aware of teh dangers or radioactivity (1 page)

  2. Electrochemical sensors based on gold nanoparticles modified with rhodamine B hydrazide to sensitively detect Cu(II)

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Donglai; Hu, Bin; Kang, Mengmeng [Henan Provincial Key Laboratory of Surface and Interface Science, Zhengzhou University of Light Industry, No. 136, Science Avenue, Zhengzhou 450001 (China); Wang, Minghua [Henan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration, Zhengzhou University of Light Industry, No.136, Science Avenue, Zhengzhou 450001 (China); He, Linghao [Henan Provincial Key Laboratory of Surface and Interface Science, Zhengzhou University of Light Industry, No. 136, Science Avenue, Zhengzhou 450001 (China); Zhang, Zhihong, E-mail: mainzhh@163.com [Henan Provincial Key Laboratory of Surface and Interface Science, Zhengzhou University of Light Industry, No. 136, Science Avenue, Zhengzhou 450001 (China); Henan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration, Zhengzhou University of Light Industry, No.136, Science Avenue, Zhengzhou 450001 (China); Fang, Shaoming, E-mail: mingfang@zzuli.edu.cn [Henan Provincial Key Laboratory of Surface and Interface Science, Zhengzhou University of Light Industry, No. 136, Science Avenue, Zhengzhou 450001 (China); Henan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration, Zhengzhou University of Light Industry, No.136, Science Avenue, Zhengzhou 450001 (China)

    2016-12-30

    Highlights: • An electrochemical sensor based on gold nanoparticles modified with rhodamine B hydrazide (AuNPs-RBH) was developed. • The sensor was applied in the highly sensitive and selective detection of Cu{sup 2+} in water. • The electrochemical sensor displays excellent regeneration, stability, and practicability for Cu{sup 2+} detection. • EIS was used to determine Cu{sup 2+} ions in an aqueous solution with the developed AuNPs-RBH-based electrochemical sensor. - Abstract: An electrochemical sensor based on gold nanoparticles (Au NPs) modified with rhodamine B hydrazide (RBH) (AuNPs-RBH) was developed and applied in the highly sensitive and selective detection of Cu{sup 2+} in water. RBH molecules were bounded onto the surface of AuNPs via the strong interaction between the amino groups and Au NPs. The chemical structure variations were characterized by X-ray photoelectron spectroscopy and fluoresence spectroscopy. Additionally, electrochemical impedance spectroscopy was used to determine Cu{sup 2+} ions in an aqueous solution with the developed AuNPs-RBH-based electrochemical sensor. Results show that the fabricated sensor exhibits good electrochemical performance because of the presence of Au NPs and high affinity with the Cu{sup 2+} resulting from the strong coordination chemistry between Cu{sup 2+} and RBH. The as-developed sensor towards detecting Cu{sup 2+} has a detection limitation of 12.5 fM within the concentration range of 0.1 pM–1 nM by using the electrochemical impedance technique. It also displays excellent selectivity, regeneration, stability, and practicability for Cu{sup 2+} detection. Therefore, the new strategy of the RBH-based electrochemical sensor exhibits great potential application in environment treatment and protection.

  3. Geoenvironmental Characterisation of Heap Leach Materials at Abandoned Mines: Croydon Au-Mines, QLD, Australia

    OpenAIRE

    Anita Parbhakar-Fox

    2016-01-01

    Heap leaching is a well-established metallurgical technology which allows metal recovery (e.g., Au, Cu, U) from low-grade ores. However, spent heap leach materials remaining at abandoned or historic mine sites may represent a potential source of contamination. At the Croydon Au-mines, heap leaching operations (1984–1985) were performed on mineralized rhyolites hosting sulphides including pyrite, galena, arsenopyrite and minor sphalerite. Characterization of spent heap leach materials (n = 14)...

  4. Postsynthesis Transformation of Insulating Cs4PbBr6 Nanocrystals into Bright Perovskite CsPbBr3 through Physical and Chemical Extraction of CsBr

    OpenAIRE

    Palazon, Francisco; Urso, Carmine; De Trizio, Luca; Akkerman, Quinten; Marras, Sergio; Locardi, Federico; Nelli, Ilaria; Ferretti, Maurizio; Prato, Mirko; Manna, Liberato

    2017-01-01

    Perovskite-related Cs4PbBr6 nanocrystals present a “zero-dimensional” crystalline structure where adjacent [PbBr6]4– octahedra do not share any corners. We show in this work that these nanocrystals can be converted into “three-dimensional” CsPbBr3 perovskites by extraction of CsBr. This conversion drastically changes the optoelectronic properties of the nanocrystals that become highly photoluminescent. The extraction of CsBr can be achieved either by thermal annealing (physical approach) or b...

  5. Elamusturundus: riigi brändimine ja Eesti bränd / Siiri Same

    Index Scriptorium Estoniae

    Same, Siiri

    2015-01-01

    Artikli autor oma 2015. a. Tallinna Tehnikaülikoolis kaitstud doktoritööst "Conceptualization of experience marketing and country branding from a marketing management perspective" ("Elamusturunduse ja riigi brändimise kontseptualiseerimine turunduse juhtimise vaatenurgast")

  6. $^{80m}$Br/$^{80}$Br a new electron-$\\gamma$ - PAC Probe

    CERN Document Server

    Correia, J G; Araújo, J P; Marques, J G; Soares, J C; Melo, A A

    2001-01-01

    Conversion electron-$\\gamma$ PAC measurements of the 49 keV - 37 keV cascade in $^{80}$Br through the intermediate 2$^{-}$ state with T$_{1/2}$=7.4 ns were performed with a system of two magnetic lens spectrometers and two BaF$_{2}$ scintillation detectors. The parent $^{80m}$Br activity with half-life of 4.4 hrs was implanted into Ni, Zn and graphite at the ISOLDE separator at CERN. The observed interaction frequency in the nickel matrix is in good agreement with the known value of the hyperfine field for Br in Ni and the magnetic moment of the 2$^{-}$ state. From the measured quadrupole interaction in Zn and graphite the electric field gradients at Br were obtained.

  7. $^{80}$Br $^{80}$Br-a new electron-gamma PAC probe

    CERN Document Server

    Correia, J G; Araújo, J P; Marques, J G; Soares, J C; Melo, A A

    2001-01-01

    Conversion electron-gamma PAC measurements of the 49-37 keV cascade in /sup 80/Br through the intermediate 2/sup -/ state with T/sub 1/2 /=7.4 ns were performed with a system of two magnetic lens spectrometers and two BaF/sub 2/ scintillation detectors. The parent /sup 80m/Br activity with a halflife of 4.4 hrs was implanted into Ni, Zn and graphite at the ISOLDE separator at CERN. The observed interaction frequency in the nickel matrix is in good agreement with the known value of the hyperfine field for Br in Ni and the magnetic moment of the 2/sup -/ state. From the measured quadrupole interaction in Zn and graphite the electric field gradients at Br were obtained. (7 refs).

  8. {sup 80m}Br/{sup 80}Br - A New Electron-Gamma PAC Probe

    Energy Technology Data Exchange (ETDEWEB)

    Correia, J. G.; Haas, H. [CERN, EP Division (Switzerland); Araujo, J. P. [IFIMUP, Fac. Ciencias (Portugal); Marques, J. G.; Soares, J. C. [Inst. Tecnologico e Nuclear (Portugal); Melo, A. A. [CFNUL (Portugal)

    2001-11-15

    Conversion electron-gamma PAC measurements of the 49-37 keV cascade in {sup 80}Br through the intermediate 2{sup -} state with T{sub 1/2}=7.4 ns were performed with a system of two magnetic lens spectrometers and two BaF{sub 2} scintillation detectors. The parent {sup 80m}Br activity with a halflife of 4.4 hrs was implanted into Ni, Zn and graphite at the ISOLDE separator at CERN. The observed interaction frequency in the nickel matrix is in good agreement with the known value of the hyperfine field for Br in Ni and the magnetic moment of the 2{sup -} state. From the measured quadrupole interaction in Zn and graphite the electric field gradients at Br were obtained.

  9. Préparation et caractérisation de catalyseurs au palladium supporté ...

    African Journals Online (AJOL)

    Les catalyseurs bimétalliques supportés sur alumine et silice palladium-or et palladium-cuivre avec des teneurs Pd-Au et Pd-Cu variant entre 0,85 à 1,42%Pd- 0,14 à 0,29%Au et 0,85 à 1,42% Pd- 0,21 à 0,28%Cu respectivement à partir des sels précurseurs de Pd(NH3)4(NO3)2, tétrachloraurate d'hydrogène, HAuCl4, ...

  10. Controlling the Orbital Sequence in Individual Cu-Phthalocyanine Molecules

    NARCIS (Netherlands)

    Uhlmann, C.; Swart, I.|info:eu-repo/dai/nl/304837652; Repp, J.

    2013-01-01

    We report on the controlled change of the energetic ordering of molecular orbitals. Negatively charged copper(II)phthalocyanine on NaCl/Cu(100) undergoes a Jahn–Teller distortion that lifts the degeneracy of two frontier orbitals. The energetic order of the levels can be controlled by Au and Ag

  11. Stability and Performance of CsPbI2Br Thin Films and Solar Cell Devices.

    Science.gov (United States)

    Mariotti, Silvia; Hutter, Oliver S; Phillips, Laurie J; Yates, Peter J; Kundu, Biswajit; Durose, Ken

    2018-01-18

    In this manuscript, the inorganic perovskite CsPbI2Br is investigated as a photovoltaic material that offers higher stability than the organic-inorganic hybrid perovskite materials. It is demonstrated that CsPbI2Br does not irreversibly degrade to its component salts as in the case of methylammonium lead iodide but instead is induced (by water vapor) to transform from its metastable brown cubic (1.92 eV band gap) phase to a yellow phase having a higher band gap (2.85 eV). This is easily reversed by heating to 350 °C in a dry environment. Similarly, exposure of unencapsulated photovoltaic devices to water vapor causes current (JSC) loss as the absorber transforms to its more transparent (yellow) form, but this is also reversible by moderate heating, with over 100% recovery of the original device performance. NMR and thermal analysis show that the high band gap yellow phase does not contain detectable levels of water, implying that water induces the transformation but is not incorporated as a major component. Performances of devices with best efficiencies of 9.08% (VOC = 1.05 V, JSC = 12.7 mA cm-2 and FF = 68.4%) using a device structure comprising glass/ITO/c-TiO2/CsPbI2Br/Spiro-OMeTAD/Au are presented, and further results demonstrating the dependence of the performance on the preparation temperature of the solution processed CsPbI2Br films are shown. We conclude that encapsulation of CsPbI2Br to exclude water vapor should be sufficient to stabilize the cubic brown phase, making the material of interest for use in practical PV devices.

  12. The role of bromide ions in seeding growth of Au nanorods.

    Science.gov (United States)

    Garg, Niti; Scholl, Clark; Mohanty, Ashok; Jin, Rongchao

    2010-06-15

    We report our findings on the important role of bromide ions in the seeding growth process of Au nanorods. The seed-mediated process constitutes a well-developed method for synthesizing gold nanorods in high yield, which is facilitated by a micelle-forming surfactant, cetyltrimethylammonium bromide (CTA-Br). Despite the tremendous work in recent years, the growth mechanism of Au nanorods has not been fully understood. Contrary to the widely accepted mechanism of CTA(+) micelle-templated growth of Au nanorods, we have identified the critical role of bromide ions in the seeding growth of Au nanorods. We found that even when the micelle-forming agent (CTA(+)) concentration is below its critical micelle concentration (cmc), bromide ions added in the form of NaBr can successfully effect the growth of Au nanorods in good yield. By controlling the concentration of externally added bromide ions, the rod shape and dimensions of the resulting Au nanoparticles can be readily controlled in the presence of only a minimum amount of CTABr (as a steric stabilizer for nanorods). High-resolution TEM studies show that the as-formed nanorods are perfectly single crystalline, instead of penta-twinned ones, and are bound by {111} and {100} facets with a [110] direction as the elongation direction. A mechanism is proposed to account for the seeding growth of single crystalline Au nanorods. Overall, this work explicitly demonstrates that Br(-) indeed serves as an important shape-directing agent for gold nanorod formation in the seed-mediated process.

  13. Mise au point

    African Journals Online (AJOL)

    31 mai 2013 ... laryngocèle interne. Une surinfection a été notée chez trois patients réalisant ainsi le tableau de pyolaryngocèle. Tous les patients ont eu un examen clinique complet comportant un examen OrL et cervico-facial ainsi qu'un examen laryngé au ... pas en communication avec la lumière laryngée. La taille.

  14. Le CRDI au Mali

    International Development Research Centre (IDRC) Digital Library (Canada)

    sur la sécurité alimentaire internationale. Le CRDI continue de soutenir des travaux de recherche au Mali, quoique dans une moindre mesure en raison de la .... souvent tenues à l'écart du processus décisionnel. Les chercheurs tentent de déterminer de quelles manières les jeunes femmes du Mali et des pays avoisinants ...

  15. Mise au point

    African Journals Online (AJOL)

    7 mai 2012 ... Le carcinome folliculaire est la deuxième tumeur maligne la plus fréquente de la thyroïde et l'invasion hématologique est le moyen de propagation le plus courant de ses métastases. Les localisations secondaires à ces cancers siègent principalement au niveau des poumons, suivi par les localisations.

  16. Le CRDI au Maroc

    International Development Research Centre (IDRC) Digital Library (Canada)

    visant à aider les secteurs de l'agriculture et du tourisme à s'adapter aux changements climatiques. Dans le cadre de recherches antérieures sur la mise au point .... France. Les manifestations et protestations survenues après 2010 et auxquelles on a donné le nom de Printemps arabe ont été annonciatrices de profondes ...

  17. Mise au point

    African Journals Online (AJOL)

    7 mai 2012 ... EPIdEMIOlOgIE ET ETIOPAThOgENIE. Les angiodysplasies osseuses des maxillaires sont rares. Les premiers cas rapportés sont ceux de Berard qui a décrit en 1842 une localisation au niveau du maxillaire supérieur et de Stanley qui a rapporté en 1849 une loca- lisation mandibulaire. une prédisposition ...

  18. Le CRDI au Kenya

    International Development Research Centre (IDRC) Digital Library (Canada)

    et de l'agriculture. En produisant des connaissances dans ces secteurs essentiels, le programme contribuera à la sécurité alimentaire et améliorera la santé au Kenya. Les noms et les frontières indiqués sur la carte n'impliquent ni reconnaissance ni acceptation officielle de la part du CRDI. C. U. R. T. C. A. R. N. EM. A. R. K.

  19. Le Brésil et sa généreuse diplomatie : un dragon amical ou un tigre de papier ?

    Directory of Open Access Journals (Sweden)

    Robert Muggah

    2012-04-01

    Full Text Available Jouissant d’une démocratie stable et d’une croissance économique vertigineuse, le Brésil est en passe de devenir une puissance mondiale. Le pays s’attelle aujourd’hui à renforcer ses relations multilatérales et bilatérales en vue de promouvoir le commerce et de réduire sa vulnérabilité à l’étranger et au niveau national. Cet article montre comment le Brésil a progressivement aligné sa politique étrangère sur la coopération Sud-Sud (CSS dans le but d’atteindre ces objectifs parallèles. Si les priorités politiques du Brésil en matière de commerce ont retenu l’attention, il en est tout autrement de ses politiques et de ses pratiques en matière d’aide au développement. En outre, il est surprenant de constater que le lien explicite entre ces deux piliers de la politique étrangère brésilienne que sont le commerce et l’aide ne suscite guère de débat. Le présent article cherche à démontrer que le nouveau programme d’aide du Brésil repose fondamentalement sur des considérations commerciales. Au cours des dix dernières années, le Brésil s’est en effet attaché à positionner son programme de politique étrangère de manière à remodeler les termes mondiaux de l’échange en sa faveur et à diminuer sa dépendance aux niveaux international et national. Les attributions relativement modestes de l’aide au développement du Brésil augmentent avec l’effort plus général de faire progresser le commerce, l’investissement étranger direct et le transfert technologique. En cherchant de nouveaux marchés pour ses produits, services et investissements, le Brésil escompte que sa position en faveur de la coopération pour le développement Sud-Sud (CDSS l’aidera à renforcer son influence dans les organisations bilatérales et multilatérales, y compris au sein de l’Organisation mondiale du commerce (OMC et du Conseil de sécurité de l’ONU.

  20. Small changes in Cu redox state and speciation generate large isotope fractionation during adsorption and incorporation of Cu by a phototrophic biofilm

    Science.gov (United States)

    Coutaud, Margot; Méheut, Merlin; Glatzel, Pieter; Pokrovski, Gleb S.; Viers, Jérôme; Rols, Jean-Luc; Pokrovsky, Oleg S.

    2018-01-01

    Despite the importance of phototrophic biofilms in metal cycling in freshwater systems, metal isotope fractionation linked to metal adsorption and uptake by biofilm remains very poorly constrained. Here, copper isotope fractionation by a mature phototrophic biofilm during Cu surface adsorption and incorporation was studied in batch reactor (BR) and open drip flow reactor (DFR) systems at ambient conditions. X-ray Absorption Spectroscopy (both Near Edge Structure, XANES, and Extended Fine Structure, EXAFS) at Cu K-edge of the biofilm after its interaction with Cu in BR experiments allowed characterizing the molecular structure of assimilated Cu and quantifying the degree of CuII to CuI reduction linked to Cu assimilation. For both BR and DFR experiments, Cu adsorption caused enrichment in heavy isotope at the surface of the biofilm relative to the aqueous solution, with an apparent enrichment factor for the adsorption process, ε65Cuads, of +1.1 ± 0.3‰. In contrast, the isotope enrichment factor during copper incorporation into the biofilm (ε65Cuinc) was highly variable, ranging from -0.6 to +0.8‰. This variability of the ε65Cuinc value was likely controlled by Cu cellular uptake via different transport pathways resulting in contrasting fractionation. Specifically, the CuII storage induced enrichment in heavy isotope, whereas the toxicity response of the biofilm to Cu exposure resulted in reduction of CuII to CuI, thus yielding the biofilm enrichment in light isotope. EXAFS analyses suggested that a major part of the Cu assimilated by the biofilm is bound to 5.1 ± 0.3 oxygen or nitrogen atoms, with a small proportion of Cu linked to sulfur atoms (NS biofilm exhibited a similar trend over time of exposure. Our study demonstrates the complexity of biological processes associated with live phototrophic biofilms, which produce large and contrasting isotope fractionations following rather small Cu redox and speciation changes during uptake, storage or release of

  1. On the evolution of Dipodium R. Br.

    OpenAIRE

    Peter O'byrne

    2014-01-01

    Dipodium R. Br. (Orchidaceae), a genus of ca. 38 species, should be divided into an Australasian clade and a Malesian clade, based on morphological and geographic evidences. Dipodium section Dipodium and section Leopardanthus (Blume) O. Kuntze are re-defined to accommodate this change. An evolutionary scenario that explains this division is proposed. The lack of diversity of floral structure in the genus is probably caused by pollinator-specificity, while the diversity of plant form may be du...

  2. Gold Nanoparticles with Stably Embedded Cu-64 and Their Use in Nanoparticle Research

    DEFF Research Database (Denmark)

    Jensen, A.I.; Frellsen, Anders Floor; Hansen, A. E.

    2016-01-01

    64Cu is a popular radionuclide for PET imaging and when 64Cu2+ is mixed with gold nanoparticles (AuNPs) it adheres to the gold surface. Taking advantage of this, we developed methods to trap the 64Cu within the AuNPs by embedding under additional layers of gold. This resulted in radiolabeling...... onto which they are attached. Radiolabeled 64Cu-AuNPs were prepared in biomedically relevant sizes of 20-30 nm and decorated with three different coatings, in order to investigate their in vivo performance by PET imaging in a murine xenograft model. We found the longest plasma half-life (T½ about 9...... hours) to result from a polyethylene glycol (PEG) coating, while faster elimination from the bloodstream was observed for both a Tween-20 stabilized coating and a zwitterionic coating based on sulfonic acids and quaternary amines. Accordingly, our data concluded the PEG coating to be most benefical...

  3. Protein mediated synthesis of fluorescent Au-nanoclusters for metal sensory coatings

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, Manja; Raff, Johannes [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biogeochemistry

    2017-06-01

    Fluorescent Au-nanocluster were successfully synthesized and used for the selective detection of Cu{sup 2} {sup +}. The synthesized Au-BSA-nanoclusters remain functional also after immobilization and show high thermal stability. Additionally, the transfer of the protein mediated Au-nanocluster synthesis route to S-layer proteins was achieved. (The presented work is part of the project BIONEWS dealing with long-term stable cells for the set-up and regeneration of sensor and actor materials for strategic relevant metals, in particular rare earth elements).

  4. Enhanced bromate formation during chlorination of bromide-containing waters in the presence of CuO: Catalytic disproportionation of hypobromous acid

    KAUST Repository

    Liu, Chao

    2012-10-16

    Bromate (BrO3 -) in drinking water is traditionally seen as an ozonation byproduct from the oxidation of bromide (Br-), and its formation during chlorination is usually not significant. This study shows enhanced bromate formation during chlorination of bromide-containing waters in the presence of cupric oxide (CuO). CuO was effective to catalyze hypochlorous acid (HOCl) or hypobromous acid (HOBr) decay (e.g., at least 104 times enhancement for HOBr at pH 8.6 by 0.2 g L-1 CuO). Significant halate concentrations were formed from a CuO-catalyzed hypohalite disproportionation pathway. For example, the chlorate concentration was 2.7 ± 0.2 μM (225.5 ± 16.7 μg L-1) after 90 min for HOCl (Co = 37 μM, 2.6 mg L-1 Cl2) in the presence of 0.2 g L-1 CuO at pH 7.6, and the bromate concentration was 6.6 ± 0.5 μM (844.8 ± 64 μg L -1) after 180 min for HOBr (Co = 35 μM) in the presence of 0.2 g L-1 CuO at pH 8.6. The maximum halate formation was at pHs 7.6 and 8.6 for HOCl or HOBr, respectively, which are close to their corresponding pKa values. In a HOCl-Br--CuO system, BrO3 - formation increases with increasing CuO doses and initial HOCl and Br- concentrations. A molar conversion (Br - to BrO3 -) of up to (90 ± 1)% could be achieved in the HOCl-Br--CuO system because of recycling of Br - to HOBr by HOCl, whereas the maximum BrO3 - yield in HOBr-CuO is only 26%. Bromate formation is initiated by the formation of a complex between CuO and HOBr/OBr-, which then reacts with HOBr to generate bromite. Bromite is further oxidized to BrO3 - by a second CuO-catalyzed process. These novel findings may have implications for bromate formation during chlorination of bromide-containing drinking waters in copper pipes. © 2012 American Chemical Society.

  5. Determining the storage, availability and reactivity of NH3 within Cu-Chabazite-based Ammonia Selective Catalytic Reduction systems

    NARCIS (Netherlands)

    Lezcano-Gonzalez, I; Deka, U; Arstad, B; Van Yperen-De Deyne, A; Hemelsoet, K; Waroquier, M; Van Speybroeck, V; Weckhuysen, B M; Beale, A M

    2014-01-01

    Three different types of NH3 species can be simultaneously present on Cu(2+)-exchanged CHA-type zeolites, commonly used in Ammonia Selective Catalytic Reduction (NH3-SCR) systems. These include ammonium ions (NH4(+)), formed on the Brønsted acid sites, [Cu(NH3)4](2+) complexes, resulting from NH3

  6. Mise au point

    African Journals Online (AJOL)

    Le forage osseux par des fraises protégées augmente la sécurité du geste, en évitant des brûlures muqueuses res- ponsables de synéchies postopératoires. Le système d'ir- rigation-aspiration associé aux fraises améliore indiscuta- blement le confort visuel de l'opérateur en évitant les pro- jections générées par le forage.

  7. Application of Cu3InSnSe5 Heteronanostructures as Counter Electrodes for Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Lou, Yue; Zhao, Wenjie; Li, Chunguang; Huang, He; Bai, Tianyu; Chen, Cailing; Liang, Chen; Shi, Zhan; Zhang, Dong; Chen, Xiao-Bo; Feng, Shouhua

    2017-05-31

    In this research, we reported the synthesis of quaternary Cu3InSnSe5 nanoparticles with uniform size distribution and morphology for the first time through delicate controls over the chemical reaction kinetics. On the basis of the preparation strategy of Cu3InSnSe5 nanoparticles, Pt-Cu3InSnSe5 and Au-Cu3InSnSe5 heteronanostructures were designed and yielded using a simple and efficient seed growth method. These two heteronanostructures remained monodispersed without presence of any Cu3InSnSe5 nanocrystal impurities. To explore their application potentials for dye-sensitized solar cells, counter electrodes consisting of individual Cu3InSnSe5, Pt-Cu3InSnSe5, or Au-Cu3InSnSe5 constituents were fabricated. Current density-voltage (J-V) characteristics evaluation reveals that Cu3InSnSe5 nanoparticles, Pt-Cu3InSnSe5 and Au-Cu3InSnSe5 heterostructured nanoparticles display a comparative power conversion efficiency (PCE) of 5.8%, 7.6%, and 6.5% to that of a Pt-based counter electrode (7.9%), respectively. As such, we believe that the reported preparation strategy could provide new insights to the design and manufacture of counter electrode materials with controlled structure, morphology, and optimized power conversion efficiency for dye-sensitized solar cells.

  8. Experimental and Mechanistic Understanding of Aldehyde Hydrogenation Using Au25 Nanoclusters with Lewis Acids: Unique Sites for Catalytic Reactions.

    Science.gov (United States)

    Li, Gao; Abroshan, Hadi; Chen, Yuxiang; Jin, Rongchao; Kim, Hyung J

    2015-11-18

    The catalytic activity of Au25(SR)18 nanoclusters (R = C2H4Ph) for the aldehyde hydrogenation reaction in the presence of a base, e.g., ammonia or pyridine, and transition-metal ions M(z+), such as Cu(+), Cu(2+), Ni(2+) and Co(2+), as a Lewis acid is studied. The addition of a Lewis acid is found to significantly promote the catalytic activity of Au25(SR)18/CeO2 in the hydrogenation of benzaldehyde and a number of its derivatives. Matrix-assisted laser desorption ionization (MALDI) and electrospray ionization (ESI) mass spectrometry in conjunction with UV-vis spectroscopy confirm the generation of new species, Au25-n(SR)18-n (n = 1-4), in the presence of a Lewis acid. The pathways for the speciation of Au24(SR)17 from its parent Au25(SR)18 nanocluster as well as its structure are investigated via the density functional theory (DFT) method. The adsorption of M(z+) onto a thiolate ligand "-SR-" of Au25(SR)18, followed by a stepwise detachment of "-SR-" and a gold atom bonded to "-SR-" (thus an "Au-SR" unit) is found to be the most likely mechanism for the Au24(SR)17 generation. This in turn exposes the Au13-core of Au24(SR)17 to reactants, providing an active site for the catalytic hydrogenation. DFT calculations indicate that M(z+) is also capable of adsorbing onto the Au13-core surface, producing a possible active metal site of a different kind to catalyze the aldehyde hydrogenation reaction. This study suggests, for the first time, that species with an open metal site like adducts [nanoparticle-M]((z-1)+) or fragments Au25-n(SR)18-n function as the catalysts rather than the intact Au25(SR)18.

  9. Mise au point

    African Journals Online (AJOL)

    31 mai 2013 ... L'attitude théra- peutique dépend du type de la laryngocèle. en effet, le traitement endoscopique au laser CO2 a gagné beaucoup d'intérêt ces dernières années. MATÉRIEL ET MÉTHOdES. Il s'agit d'une étude rétrospective portant sur 9 patients porteurs d'une laryngocèle colligés sur une période de 14.

  10. Le CRDI au Ghana

    International Development Research Centre (IDRC) Digital Library (Canada)

    poussée en mathématiques aux spécialistes de demain afin qu'ils puissent relever les défis pressants qui se posent en matière d'environnement, de santé et d'économie. La bourse de chercheur invité que le CRDI a octroyée en 2001 au regretté. John Atta-Mills, qui a par la suite été prési- dent du Ghana de 2009 à 2012, ...

  11. Au pairs on Facebook

    DEFF Research Database (Denmark)

    Dalgas, Karina Märcher

    2016-01-01

    Ethnographers are increasingly making use of Facebook to acquire access and general acquaintance with their field of study. However, little has been written on how Facebook is used methodologically in research that does not have social media sites as the main focus of interest. This article argues...... that engagement with Facebook as a methodological tool can be useful in research among migrants in highly politicised fields. Pointing to a discursive construction of Filipina au pairs as victims of labour exploitation, the article shows how fieldwork on Facebook enables the exploration of the ways in which...... and on Facebook....

  12. Mise au point

    African Journals Online (AJOL)

    7 mai 2012 ... acquis et des anomalies génétiques associées ont été aussi incriminés (mutation du gène Fas ou de la p53, délétion au niveau du chromosome 6q, méthylation excessive de la p73) (15,16). Le mode de révélation de ces lymphomes est peu spéci- fique et parfois banal. L'obstruction nasale représente le.

  13. Octadecabromidobis(dicarbidodecadysprosium, [Dy10Br18(C22

    Directory of Open Access Journals (Sweden)

    Kathrin Daub

    2008-01-01

    Full Text Available Single crystals of [Dy10Br18(C22] were obtained during the reaction of DyBr3 with dysprosium metal and graphite in a sealed tantalum container. In the crystal structure, the Dy atoms form dimers of edge-sharing octahedra, each encapsulating a C2 unit. The metal atoms are surrounded by Br atoms above the cluster edges and vertices, respectively. The dimers are connected to each other by Br atoms, leading to a three-dimensional network. [Dy10Br18(C22] is isotypic with its iodido analogue [Dy10I18(C22].

  14. Facet-Dependent Optical Properties Revealed through Investigation of Polyhedral Au-Cu₂O and Bimetallic Core-Shell Nanocrystals.

    Science.gov (United States)

    Huang, Michael H; Rej, Sourav; Chiu, Chun-Ya

    2015-06-01

    The ability to prepare Au-Cu2O core-shell nanocrystals with precise control over particle size and shape has led to the discovery of facet-dependent optical properties in cuprous oxide crystals. The use of Au cores not only allows the successful formation of Au-Cu2O core-shell nanocrystals with tunable sizes, but also enables the observation of facet-dependent optical properties in these crystals through the Au localized surface plasmon resonance (LSPR) absorption band. By tuning the Cu2O shell morphology from rhombic dodecahedral to octahedral and cubic structures, and thus the exposed facets, the Au LSPR band position can be widely tuned. Such facet-dependent optical effects are not observed in bimetallic Au-Ag and Au-Pd core-shell nanocrystals with the same precisely tuned particle sizes and shapes. It is believed that similar facet-dependent optical properties could be observed in other ionic solids and other metal-metal oxide systems. The unusually large degree of plasmonic band tuning covering from the visible to the near-infrared region in this type of nanostructure should be quite useful for a range of plasmonic applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Charged particle density distributions in Au+ Au collisions at ...

    Indian Academy of Sciences (India)

    ... measured in Au + Au collisions using the BRAHMS detector at RHIC. The results are presented as a function of the collision centrality and the center of mass energy. They are compared to the predictions of different parton scattering models and the important role of hard scattering processes at RHIC energies is discussed ...

  16. Solid Inclusions in Au-nuggets, genesis and derivation from alkaline rocks of the Guli Massif, Northern Siberia

    Science.gov (United States)

    Dvorani, Sami N.

    2016-04-01

    A total of 112 Au-nuggets, collected from alluvial placer deposits of the Ingarinda River from the Guli massif, located in northem Siberia, Russia, were investigated. The Guli massif consists of a huge dunite-clinopyroxenite complex (the largest complex in the world), an alkaline to highly alkaline rock suite (melilite, nephelinite, ijolite) enveloping the dunite and carbonatite intrusions, associated with disseminated schlieren type chromitite and Au-Ag, Pt placer deposits. The nuggets are characterized by various sizes and shapes and show chemical compositions Au, Au-Ag and AuCu, typical for a derivate of carbon-atites and/or ultramafic complexes. A great variety of oxide, silicate, REE-minerals, carbonate and sulphide inclusions have been detected in the nuggets, which are identical in mineralogy and chemical composition to mineral constituents of the alkaline to highly alkaline rock suite surrounding the Guli dunite core complex thus, considered as the source for Au-nuggets.

  17. Solid Inclusions in Au-nuggets, genesis and derivation from alkaline rocks of the Guli Massif, Northern Siberia

    Directory of Open Access Journals (Sweden)

    Dvorani Sami N.

    2016-04-01

    Full Text Available A total of 112 Au-nuggets, collected from alluvial placer deposits of the Ingarinda River from the Guli massif, located in northem Siberia, Russia, were investigated. The Guli massif consists of a huge dunite-clinopyroxenite complex (the largest complex in the world, an alkaline to highly alkaline rock suite (melilite, nephelinite, ijolite enveloping the dunite and carbonatite intrusions, associated with disseminated schlieren type chromitite and Au-Ag, Pt placer deposits. The nuggets are characterized by various sizes and shapes and show chemical compositions Au, Au-Ag and AuCu, typical for a derivate of carbon-atites and/or ultramafic complexes. A great variety of oxide, silicate, REE-minerals, carbonate and sulphide inclusions have been detected in the nuggets, which are identical in mineralogy and chemical composition to mineral constituents of the alkaline to highly alkaline rock suite surrounding the Guli dunite core complex thus, considered as the source for Au-nuggets.

  18. Ni- or Cu-catalyzed cross-coupling reaction of alkyl fluorides with Grignard reagents.

    Science.gov (United States)

    Terao, Jun; Ikumi, Aki; Kuniyasu, Hitoshi; Kambe, Nobuaki

    2003-05-14

    n-Octyl fluoride underwent a cross-coupling reaction with n-propylmagnesium bromide in the presence of 1,3-butadiene using NiCl2 as a catalyst at room temperature to give undecane in moderate yields. This alkyl-alkyl cross-coupling proceeded more efficiently when CuCl2 was employed instead of NiCl2. Addition of 1,3-butadiene dramatically improved the yields of the coupling products from primary alkyl Grignard reagents in both Ni- and Cu-catalyzed reactions. Alkyl fluorides efficiently reacted with tertiary alkyl and phenyl Grignard reagents using CuCl2 in the absence of 1,3-butadiene to afford the coupling products in high yields. The competitive reaction of a mixture of alkyl halides (R-X; X = F, Cl, Br) with nC5H11MgBr showed that the reactivities of the halides increase in the order R-Cl R-F R-Br. In contrast, in the Cu-catalyzed reaction with PhMgBr, the reactivities increase in the order R-Cl R-Br R-F.

  19. Prévenir les maladies liées au virus Zika avec de nouvelles ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Ces dernières années, c'est en Amérique latine qu'on a observé le nombre le plus élevé de cas de dengue, soit au Brésil, en Colombie et au Mexique. Ces pays ont aussi été confrontés à des épidémies de chikungunya (2014-2015) et du virus Zika (2015-2016). Les trois infections sont transmises par le même vecteur de ...

  20. Kinetics of the Reactions of O((sup 3)P) and Cl((sup 2)P) with HBr and Br2

    Science.gov (United States)

    Nicovich, J. M.; Wine, P. H.

    1997-01-01

    A laser flash photolysis-resonance fluorescence technique has been employed to study the kinetics of reactions (1)-(4) as a function of temperature. (1) O((sup 3)P) + Br2 yields BrO + Br((sup 2)P(sub 3/2)) at 255-350 K; (2) Cl((sup 2)P) + Br2 yields BrCl + Br((sup 2)P(sub 3/2)) at 298-401 K; (3) O((sup 3)P) + HBr yields OH + Br((sup 2)P(sub J)) at 250-402 K; (4) Cl((sup 2)P) + HBr yields HCl + Br((sup 2)P(sub J)) at 257-404 K. In all cases, the concentration of the excess reagent, i.e, HBr or Br2, was measured in situ in the slow flow system by UV-visible photometry. Heterogeneous dark reactions between XBr (X equals H or Br) and the photolytic precursors for Cl((sup 2)P) and O((sup 3)P) (Cl2 and O3, respectively) were avoided by injecting minimal amounts of precursor into the reaction mixture immediately upstream from the reaction zone. The following Arrhenius expressions summarize our results (errors are 2 sigma and represent precision only, units are cu cm/(molecule.s): k(sub 1) = (1.76 +/- 0.80) x 10(exp -11 exp[(40 +/- 100)/T]; k(sub 2) = (2.40 +/- 1.25) x 12(exp -10) exp[-(144 +/- 176)/T]; k(sub 3) = (5.11 +/- 2.82) x 10(exp -12) exp[-(1450 +/- 160)/T]; k(sub 4) = (2.25 +/- 0.56) x 10(exp -11) exp[-(400 +/- 80)/T]. The consistency (or lack thereof) of our results with those reported in previous kinetics and dynamics studies of reactions (1)-(4) is discussed.

  1. Effects of monolayer Bi on the self-assembly of DBBA on Au(111)

    Science.gov (United States)

    Tian, Guo; Shen, Yixian; He, Bingchen; Yu, Zhengqing; Song, Fei; Lu, Yunhao; Wang, Pingshan; Gao, Yongli; Huang, Han

    2017-11-01

    The initial growth behaviors of nonplanar 10,10‧-dibromo-9,9‧-bianthryl (DBBA) molecules on the Au(111) substrates, which is either pristine or Bi-3 × √3-Au(111), at low deposition rates have been systematically investigated using low temperature scanning tunneling microscopy (LT-STM) and density functional theories (DFT) calculations. The effects of such substrates on the subsequent graphene nanoribbons (GNRs) formation are addressed. On clean Au(111), DBBA molecules self-assemble into highly ordered commensurate single-molecule chains along 11 2 bar >Au at a coverage of 0.8 monolayer (ML), and collectively transit into long-range ordered commensurate double-molecule chains along 1 1 bar 0 >Au but with many single-molecule vacancies at a coverage of 1.2 ML, revealing the delicate competing between intermolecular interactions and molecule-substrate interfacial interactions. The interfacial interactions are further tuned by introducing bismuth to form a Bi-3 × √3-Au(111)surface, where DBBA molecules self-assemble into an unique hexamer phase due to the enhanced intermolecular interactions via Csbnd H…π and halogen bonds. DFT calculations confirm the proposed molecular configuration change of single DBBA molecule when adsorbed on different substrates. The calculated difference in Csbnd Br bond gives further insight into why no GNRs formed on Bi-3 × √3-Au(111).

  2. Modeling of the Radial Heat Flow and Cooling Processes in a Deep Ultraviolet Cu+ Ne-CuBr Laser

    Directory of Open Access Journals (Sweden)

    Iliycho Petkov Iliev

    2009-01-01

    Full Text Available An improved theoretical model of the gas temperature profile in the cross-section of an ultraviolet copper ion excited copper bromide laser is developed. The model is based on the solution of the one-dimensional heat conduction equation subject to special nonlinear boundary conditions, describing the heat interaction between the laser tube and its surroundings. It takes into account the nonuniform distribution of the volume power density along with the radius of the laser tube. The problem is reduced to the boundary value problem of the first kind. An explicit solution of this model is obtained. The model is applied for the evaluation of the gas temperature profiles of the laser in the conditions of free and forced air-cooling. Comparison with other simple models assumed constant volume power density is made. In particular, a simple expression for calculating the average gas temperature is found.

  3. Conductive One- and Two-Dimensional Structures Fabricated Using Oxidation-Resistant Cu-Sn Particles.

    Science.gov (United States)

    Liang, Yujia; Hou, Huilong; Yang, Yong; Glicksman, Howard; Ehrman, Sheryl

    2017-10-11

    Cu-Sn powders are promising alternatives to Ag and Au in applications including printed electronics because of their low cost and high oxidation resistance. Further development requires knowledge of the conductivity of their corresponding one- and two-dimensional structures. Herein, CuSny (y = atom ratio of Sn/Cu) wires and films were produced by direct printing. In situ measurements of structural resistivities with variation of the temperature from 2 to 400 K in oxygen-free conditions revealed that CuSn0.1 wires have resistivities comparable to those of Cu wires. Furthermore, CuSn0.1 films exhibited significantly lower resistivity increases after being heated at 573 K in ambient air, compared with Cu films.

  4. Gang de jeunes et groupes armés dans la Région Métropolitaine de Belo Horizonte, Minas Gerais, Brésil

    OpenAIRE

    Zilli, Luis Felipe; Beato,Cláudio

    2015-01-01

    Cet article prend pour objet les recherches sociologiques traitant de l’implication de jeunes dans des dynamiques de violence et de criminalité des quartiers pauvres et des banlieues de grands centres urbains. Il présente les principaux résultats d’une recherche empirique sur les gangs de jeunes et les groupes armés qui opèrent dans les favelas de la région de Belo Horizonte (RMBH), capitale de l’État de Minas Gerais, au Brésil. Du point de vue théorique, nous adoptons ici le postulat qu’au B...

  5. Hybridization of Single Nanocrystals of Cs4PbBr6 and CsPbBr3

    Science.gov (United States)

    2017-01-01

    Nanocrystals of all-inorganic cesium lead halide perovskites (CsPbX3, X = Cl, Br, I) feature high absorption and efficient narrow-band emission which renders them promising for future generation of photovoltaic and optoelectronic devices. Colloidal ensembles of these nanocrystals can be conveniently prepared by chemical synthesis. However, in the case of CsPbBr3, its synthesis can also yield nanocrystals of Cs4PbBr6 and the properties of the two are easily confused. Here, we investigate in detail the optical characteristics of simultaneously synthesized green-emitting CsPbBr3 and insulating Cs4PbBr6 nanocrystals. We demonstrate that, in this case, the two materials inevitably hybridize, forming nanoparticles with a spherical shape. The actual amount of these Cs4PbBr6 nanocrystals and nanohybrids increases for synthesis at lower temperatures, i.e., the condition typically used for the development of perovskite CsPbBr3 nanocrystals with smaller sizes. We use state-of-the-art electron energy loss spectroscopy to characterize nanoparticles at the single object level. This method allows distinguishing between optical characteristics of a pure Cs4PbBr6 and CsPbBr3 nanocrystal and their nanohybrid. In this way, we resolve some of the recent misconceptions concerning possible visible absorption and emission of Cs4PbBr6. Our method provides detailed structural characterization, and combined with modeling, we conclusively identify the nanospheres as CsPbBr3/Cs4PbBr6 hybrids. We show that the two phases are independent of each other’s presence and merge symbiotically. Herein, the optical characteristics of the parent materials are preserved, allowing for an increased absorption in the UV due to Cs4PbBr6, accompanied by the distinctive efficient green emission resulting from CsPbBr3. PMID:28919935

  6. Magnetoresistance of Au films

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D. L., E-mail: zhangdl@iphy.ac.cn; Song, X. H.; Zhang, X. [Institute of Physics, Chinese Academy of Sciences, Beijing 10081 (China); Zhang, X.-G., E-mail: xgz@ufl.edu [Department of Physics and Quantum Theory Project, University of Florida, Gainesville, Florida 32611 (United States); Center for Nanophase Materials Sciences and Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6493 (United States)

    2014-12-14

    Classical magnetoresistance (MR) in nonmagnetic metals are conventionally understood in terms of the Kohler rule, with violation usually viewed as anomalous electron transport, in particular, as evidence of non-Fermi liquid behavior. Measurement of the MR of Au films as a function of temperature and film thickness reveals a strong dependence on grain size distribution and clear violation of the Kohler rule. Using a model of random resistor network, we show that this result can be explained if the MR arises entirely from inhomogeneity due to grain boundary scattering and thermal activation of grain boundary atoms. Consequently, the Kohler rule should not be used to distinguish normal and anomalous electron transport in solids.

  7. Postsynthesis Transformation of Insulating Cs4PbBr6 Nanocrystals into Bright Perovskite CsPbBr3 through Physical and Chemical Extraction of CsBr

    Science.gov (United States)

    2017-01-01

    Perovskite-related Cs4PbBr6 nanocrystals present a “zero-dimensional” crystalline structure where adjacent [PbBr6]4– octahedra do not share any corners. We show in this work that these nanocrystals can be converted into “three-dimensional” CsPbBr3 perovskites by extraction of CsBr. This conversion drastically changes the optoelectronic properties of the nanocrystals that become highly photoluminescent. The extraction of CsBr can be achieved either by thermal annealing (physical approach) or by chemical reaction with Prussian Blue (chemical approach). The former approach can be simply carried out on a dried film without addition of any chemicals but does not yield a full transformation. Instead, reaction with Prussian Blue in solution achieves a full transformation into the perovskite phase. This transformation was also verified on the iodide counterpart (Cs4PbI6). PMID:29285525

  8. Ozone Depletion Potential of CH3Br. Appendix H

    Science.gov (United States)

    Ko, Malcolm K. W.; Sze, Nien Dak; Scott, Courtney; Rodriguez, Jose M.; Weisenstein, Debra K.; Sander, Stanley P.

    1998-01-01

    The ozone depletion potential (ODP) of methyl bromide (CH3Br) can be determined by combining the model-calculated bromine efficiency factor (BEF) for CH3Br and its atmospheric lifetime. This paper examines how changes in several key kinetic data affect BEF. The key reactions highlighted in this study include the reaction of BrO + HO2, the absorption cross section of HOBr, the absorption cross section and the photolysis products of BrONO2, and the heterogeneous conversion of BrONO2 to HOBr and HNO3 on aerosol particles. By combining the calculated BEF with the latest estimate of 0.7 year for the atmospheric lifetime of CH3Br, the likely value of ODP for CH3Br is 0.39. The model-calculated concentration of HBr (approx. 0.3 pptv) in the lower stratosphere is substantially smaller than the reported measured value of about 1 pptv. Recent publications suggested models can reproduce the measured value if one assumes a yield for HBr from the reaction of BrO + OH or from the reaction of BrO + HO2. Although the evaluation concluded any substantial yield of HBr from BrO + HO2 is unlikely, for completeness, we calculate the effects of these assumed yields on BEF for CH3Br. Our calculations show that the effects are minimal: practically no impact for an assumed 1.3% yield of HBr from BrO + OH and 10% smaller for an assumed 0.6% yield from BrO + HO2.

  9. Semi-Transparent ZnO-CuI/CuSCN Photodiode Detector with Narrow-Band UV Photoresponse.

    Science.gov (United States)

    Yang, Zhi; Wang, Minqiang; Ding, Jijun; Sun, Zhongwang; Li, Le; Huang, Jin; Liu, Jing; Shao, Jinyou

    2015-09-30

    The ZnO homogeneous pn junction photodiode is quite difficult to fabricate due to the absence of stable p-type ZnO. So exploring reliable p-type materials is necessary to build a heterogeneous pn junction with n-type ZnO. Herein, we develop a simple and low-cost solution-processed method to obtain inorganic p-type CuI/CuSCN composite film with compact morphology, high conductivity, and low surface state. The improved performance of CuI/CuSCN composite film can be confirmed based on high-rectification ratio, responsivity, and open voltage of ZnO-CuI/CuSCN photodiode UV detectors. Moreover, photodiodes with novel top electrodes are investigated. Compared with commonly used Au and graphene/Ag nanowire (NWs) electrode, poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) ( PSS) electrode prepared by Meyer rod-coating technique opens one route to obtain a semitransparent photodiode. The photodiode with PSS as the top electrode under reverse illumination has the highest photocurrent density due to higher UV transmittance of PSS transparent electrode compared with ITO glass. The low-energy consumption, and high responsivity, UV to visible rejection ratio and air stability make this ZnO-CuI/CuSCN photodiode quite promising in the UV-A detection field.

  10. Dynamics of copper-phthalocyanine molecules on Au/Ge(001)

    Energy Technology Data Exchange (ETDEWEB)

    Sotthewes, K.; Heimbuch, R.; Zandvliet, H. J. W. [Physics of Interfaces and Nanomaterials, MESA" + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede (Netherlands)

    2015-10-07

    Spatially resolved current-time scanning tunneling spectroscopy combined with current-distance spectroscopy has been used to characterize the dynamic behavior of copper-phthalocyanine (CuPc) molecules adsorbed on a Au-modified Ge(001) surface. The analyzed CuPc molecules are adsorbed in a “molecular bridge” configuration, where two benzopyrrole groups (lobes) are connected to a Au-induced nanowire, whereas the other two lobes are connected to the adjacent nanowire. Three types of lobe configurations are found: a bright lobe, a dim lobe, and a fuzzy lobe. The dim and fuzzy lobes exhibit a well-defined switching behavior between two discrete levels, while the bright lobe shows a broad oscillation band. The observed dynamic behavior is induced by electrons that are injected into the LUMO+1 orbital of the CuPc molecule. By precisely adjusting the tip-molecule distance, the switching frequency of the lobes can be tuned accurately.

  11. Degradation of contaminants by Cu{sup +}-activated molecular oxygen in aqueous solutions: Evidence for cupryl species (Cu{sup 3+})

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Yong, E-mail: fengy@hku.hk [Department of Civil Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong); Lee, Po-Heng, E-mail: phlee@polyu.edu.hk [Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Wu, Deli, E-mail: wudeli@tongji.edu.cn [State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science & Engineering, Tongji University, Shanghai 200092 (China); Zhou, Zhengyuan, E-mail: zzy247@hku.hk [Department of Civil Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong); Li, Hangkong, E-mail: hangkong@hku.hk [Department of Civil Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong); Shih, Kaimin, E-mail: kshih@hku.hk [Department of Civil Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong)

    2017-06-05

    Highlights: • Sulfadiazine and methylene blue were nearly completely degraded by Cu{sup +}-O{sub 2} oxidation. • Reaction of Cu{sup +} and hydrogen peroxide produced Cu{sup 3+} as the major active species. • 5,5-dimethyl-2-hydroxypyrrolidine-N-oxyl (DMPO-OH) was found in the reaction process. • Benzoic acid and electron paramagnetic resonance are not capable to differentiate Cu{sup 3+} and ·OH. - Abstract: Copper ions (Cu{sup 2+} and Cu{sup +}) have shown potential as Fenton-like activators for the circumneutral removal of organic contaminants from aqueous solutions. However, the major active species (cupryl species (Cu{sup 3+}) versus hydroxyl radical (·OH)) produced during the activation of hydrogen peroxide by Cu{sup +} remain unclear. In this study, Cu{sup +}-O{sub 2} oxidation, in which hydrogen peroxide is produced via the activated decomposition of dissolved molecular oxygen, was used to degrade sulfadiazine, methylene blue, and benzoic acid. The results showed that both sulfadiazine and methylene blue could be efficiently degraded by Cu{sup +}-O{sub 2} oxidation in a wide effective pH range from 2.0 to 10.0. Quenching experiments with different alcohols and the effect of Br{sup −} suggested that Cu{sup 3+} rather than ·OH was the major active species. Electron paramagnetic resonance detected 5,5-dimethyl-2-hydroxypyrrolidine-N-oxyl (DMPO-OH), which was probably produced by the oxidation of DMPO by Cu{sup 3+} or ·OH formed as a product of Cu{sup 3+} decomposition. 4-hydroxybenzoic acid was produced during the degradation of benzoic acid by Cu{sup 3+}. The findings of this study may help to explain the inconsistency regarding the dominant active species produced by the interaction of Cu{sup +} and hydrogen peroxide.

  12. Phytostabilisation of a copper contaminated topsoil aided by basic slags: assessment of Cu mobility and phytoavailability

    OpenAIRE

    Le Forestier, Lydie; Motelica-Heino, Mikael; Le Coustumer, Philippe; Mench, Michel

    2017-01-01

    Purpose Basic slags are alkaline by-products of the steel industry with potential properties to ameliorate nutrient supply and metal stabilisation in contaminated soils. This study aimed at investigating the potential of a P-spiked Link Donawitz slag and a conventional basic slag called Carmeuse for the aided phytostabilisation of a Cu-contaminated soil at a wood treatment site. The effects of basic slag addition on Cu fractionation, mobility and (phyto) availability were assessed.[br/] ...

  13. Doping Cu{sub 2}O in Electrolyte Solution: Dopant Incorporation, Atomic Structures and Electrical Properties

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Meng; Zhang, Qiming

    2013-11-24

    We have pursued a number of research activities between April 2010 and April 2011: A detailed study on n-type doping in Cu2O by Br; An analysis of natural resource limitations to terawatt-scale solar cells; Attempt to achieve a 1.4-eV direct band gap in Ni sulfides (NiSx); First-principles studies of doping in Cu2O and electronic structures of NiSx.

  14. De l’art engage à la contre-culture : la scène musicale brésilienne (1969-1974)

    OpenAIRE

    Castro Diniz, Sheyla

    2015-01-01

    Au début des années 1970, le Brésil a vu se développer une production musicale liée aux idéaux de la contre-culture sous la répression politique de la dictature militaire. Paradoxalement, l’État brésilien a, en intervenant massivement dans l’économie, rendu possible l’essor du marché de la musique. Tandis que s’éloignait la perspective d’une révolution sociale, plusieurs musiciens ont assumé des postures hippies, marginales ou desbundadas, en rupture non seulement avec l’ordre établi, mais au...

  15. Discharge flow kinetic study of the reactions of NO sub 3 with Br, BrO, HBr, and HCl

    Energy Technology Data Exchange (ETDEWEB)

    Mellouki, A.; Poulet, G.; Le Bras, G. (C.N.R.S., Orleans (France)); Singer, R.; Burrows, J.P.; Moortgat, G.K. (Max-Planck Institut fuer Chemie, Mainz (Germany, F.R.))

    1989-11-30

    The reactions of NO{sub 3} with Br, BrO, HBr, and HCl have been studied at 298 K by using the discharge-flow EPR method. In the study of the reactions of NO{sub 3} with Br and BrO, where NO{sub 3} and Br or BrO were flowed separately in the presence of excess NO{sub 3}, the following rate constants were found: k{sub 1} = (1.6 {plus minus} 0.7) {times} 10{sup {minus}11} for NO{sub 3} + Br {yields} NO{sub 2} + BrO (1) and 0.3 {times} 10{sup {minus}12} {le} k{sub 3} {le} 3 {times} 10{sup {minus}12} for NO{sub 3} + BrO {yields} Br + NO{sub 2} + O{sub 2} (3). Units are cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}. For the reactions NO{sub 3} + HCl {yields} products (6) and NO{sub 3} + HBr {yields} products (7), the upper limits k{sub 6} {le} 5 {times} 10{sup {minus}17} and k{sub 7} {le} 1 {times} 10{sup {minus}16} were obtained.

  16. 197Au Mössbauer study of copper refinery anode slimes

    Science.gov (United States)

    Sawicki, J. A.; Dutrizac, J. E.; Friedl, J.; Wagner, F. E.; Chen, T. T.

    1993-06-01

    Copper refinery anode slimes are abundantly produced during the electrolytic refining of copper. Although the slimes contain significant and economically recoverable amounts of gold and silver, the chemical state of the gold has not been fully identified. In the present work, the chemical form of gold in a copper anode, in a raw slime, and in slimes treated by different leaching procedures has been investigated by Mössbauer spectroscopy with the 77.3 keV γ-rays of197Au. The Mössbauer spectrum of the anode is typical of a dilute Au:Cu alloy. The spectrum of the raw slime consists of two components, namely, a single, rather broad line with an isomer shift (IS) of about -0.3 mm/s relative to a Pt metal source and a quadrupole doublet with an IS of + 1.2 mm/s and a quadrupole splitting of 5.0 mm/s. The single line component can be attributed to a gold-rich alloy, with an approximate composition of Au60Ag{n40} or Au80Cu20 if it is a binary alloy, or to a ternary Au-Ag-Cu alloy of appropriate composition. The parameters of the quadrupole doublet match those of Ag3AuSe2 (fischesserite) or related Ag2-xAuxSe compounds. In these compounds, the gold atoms are coordinated by two selenium atoms in a linear arrangement, as is typical for Au(I). It was found that the ratio between the concentrations of the metallic phase and the selenide strongly depends on the leaching conditions. The measurement of the Lamb-Mössbauer factor of fischesserite is also reported.

  17. Self-generated etchant for synthetic sculpturing of Cu 2O-Au, Cu 2O@Au, Au/Cu 2O, and 3D-Au nanostructures

    KAUST Repository

    Pang, Maolin

    2012-10-09

    Structures of Gold: A simple transformative method for nanoscale sculpturing has been developed. Five different types of complex nanocomposites of cuprite and gold have been formed by using this self-etching approach (see figure). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Brüssel Euroopa pealinnaks? / Ülar Mark

    Index Scriptorium Estoniae

    Mark, Ülar, 1968-

    2009-01-01

    Brüsseli Euroopa kvartali planeerimisvõistlusest, mille peakorraldaja oli Brüsseli pealinna piirkond koos Brüsseli linna ja Euroopa Komisjoniga. Eestist osales žüriis arhitekt Ülar Mark. Meeskonna Atelier Christian de Portzamparc võidutööst ja teiste teise vooru pääsenud nelja meeskonna (JDS / Julien De Smedt Architects, OMA / Office for Metropolitan Architecture, Xaveer De Geyter Architect, Fletcher Priest Architects) töödest

  19. Multifragmentation in Au + Au collisions studied with AMD-V

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Akira [Tohoku Univ., Sendai (Japan). Faculty of Science

    1998-07-01

    AMD-V is an optimum model for calculation of multifragmentation in Au + Au collisions. AMD-V consider anti-symmetry of incident nucleus, target nucleus and fragments, furthermore, it treat the quantum effect to exist many channels in the intermediate and final state. 150 and 250 MeV/nucleon incident energy were used in the experiments. The data of multifragment atom in {sup 197}Au + {sup 197}Au collisions was reproduced by AMD-V calculation using Gognny force, corresponding to the imcompressibility of nuclear substance K = 228 MeV and its mean field depend on momentum. When other interaction (SKG 2 force, corresponding to K = 373 KeV) was used an mean field does not depend on momentum, the calculation results could not reproduce the experimental values, because nucleus and deuteron were estimated too large and {alpha}-particle and intermediate fragments estimated too small. (S.Y.)

  20. BrO measurements over the Eastern North-Atlantic

    Directory of Open Access Journals (Sweden)

    U. Platt

    2009-12-01

    Full Text Available The aim of the work presented here was to detect BrO in the marine boundary layer over the Eastern North-Atlantic by Multi AXis-Differential Optical Absorption Spectroscopy (MAX-DOAS of scattered sunlight. With this technique, information about the concentration and the vertical profile of trace gases in the atmosphere can be gained. BrO can be formed in the marine atmosphere by degradation of biogenic organohalogens or by oxidation of bromide in sea salt aerosol. BrO influences the chemistry in marine air in many ways, e.g. since it catalytically destroys ozone, changes the NO2/NO-ratio as well as the OH/HO2-ratio and oxidises DMS. However, the abundance and the significance of BrO in the marine atmosphere is not yet fully understood. <br>> We report on data collected during a ship cruise, which took place along the West African Coast in February 2007, within the framework of the Surface Ocean PRocesses in the ANthropocene project (SOPRAN. Tropospheric BrO could be detected during this cruise at peak mixing ratios of (10.2±3.7 ppt at an assumed layer height of 1 km on 18 February 2007. Furthermore, it was found that the mean BrO concentrations increased when cruising close to the African Coast suggesting that at least part of the BrO might have originated from there.

  1. Hurtigste versus mest brændstoføkonomiske ruter

    DEFF Research Database (Denmark)

    Andersen, Ove; Krogh, Benjamin Bjerre; Lahrmann, Harry

    2013-01-01

    Der er stort fokus på at forbedre brændstoføkonomien i transportbranchen generelt. I denne artikel anvendes brændstoftallene fra Controller Area Network Bus (CANBus) kombineret med GPS data til at skabe et digitalt vejkort, hvor det er muligt at sammenligne de hurtigste ruter med de mest...... brændstoføkonomiske ruter. Kortet er baseret på ca. 100 millioner CANBus observationer og ca. 2,1 milliarder GPS observationer. Hovedkonklusionen er, at CANBus data kan anvendes til at estimere brændstofforbruget for en rute. Sammenlignet med estimering af køretider er det mere kompliceret at estimere...

  2. Product vibrational distributions in CH 3Br photodissociation

    Science.gov (United States)

    Escure, Christelle; Leininger, Thierry; Lepetit, Bruno

    2009-09-01

    We performed a theoretical study of the photodissociation dynamics of CH 3Br in the A˜ band using a wavepacket propagation technique on coupled ab initio potential energy surfaces corresponding to the 3Q 1 and 1Q 1 states correlated at large distance with the Br ground spin-orbit state, as well as the 3Q 0 and 4E states correlated to the excited one. The methyl umbrella vibrational product state distributions are found in very good agreement with experimental results. They are hotter for Br than for Br ∗, and this is related to the shapes of the 3Q 0 and 1Q 1 potentials.

  3. Catalytic monolayer voltammetry and in situ scanning tunneling microscopy of copper nitrite reductase on cysteamine-modified Au(111) electrodes

    DEFF Research Database (Denmark)

    Zhang, Jingdong; Welinder, A.C.; Hansen, Allan Glargaard

    2003-01-01

    and the actual rate constant 120-220 s(-1) is much closer to the values in homogeneous solution. The results show that AxCuNiR can be brought to immobilization in a functional state on suitably modified, well-defined, atomically planar Au(111)-electrode surfaces. This would be important for forthcoming......We have studied the adsorption and electrocatalysis of the redox metalloenzyme blue copper nitrite reductase from Achromobacter xylosoxidans (AxCuNiR) on single-crystal Au(111)-electrode surfaces modified by a self-assembled monolayer of cysteamine. A combination of cyclic voltammetry and in situ...

  4. Systèmes d'innovation des pays BRICS (Brésil, Russie, Inde, Chine ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Le Brésil, la Russie, l'Inde, la Chine et l'Afrique du Sud (dits pays BRICS) ont placé l'innovation au coeur de leur stratégie de développement. Toutefois, les chercheurs disposent de très peu de connaissances sur le système d'innovation de chacun de ces pays et sur les répercussions qu'il a sur l'économie. La subvention ...

  5. In situ Spectroscopy of Solid-State Chemical Reaction in PbBr2-Deposited CsBr Crystals

    Science.gov (United States)

    Kondo, Shin-ichi; Matsunaga, Toshihiro; Saito, Tadaaki; Asada, Hiroshi

    2003-09-01

    It is possible to measure the fundamental optical absorption spectra of CsPbBr3 and Cs4PbBr6, whose stability is predicted by the study of phase diagram in the binary system CsBr-PbBr2, by means of in situ optical absorption and reflection spectroscopy of thermally induced solid-state chemical reaction in PbBr2-deposited CsBr crystals. On heavy annealing of the crystals, the Pb2+ ions are uniformly dispersed in the crystal matrix. The present experiment provides a novel method for measuring intrinsic optical absorption of ternary metal halides and also for in situ monitoring of doping metal halide crystal with impurities (metal ions or halogen ions).

  6. Determination of nuclear cross-section of 81Br (n,,,) Br82 reaction by ...

    African Journals Online (AJOL)

    ... flux of 4.2 x 1013 n cm-2 s-1. The BaBr2 was chemically processed and measured as Hydrogen Bromide (HBr82). The value of nuclear cross-section was determined to be 2.1 0.2 barns, which falls within the range of values as previously reported elsewhere. (Journal of Applied Science and Technology: 2001 6(1-2): 4-6) ...

  7. Face au risque

    CERN Document Server

    Grosse, Christian; November, Valérie

    2007-01-01

    Ce volume collectif sur le risque inaugure la collection L'ÉQUINOXE. Ancré dans l'histoire pour mesurer les continuités et les ruptures, il illustre la manière dont les sciences humaines évaluent et mesurent les enjeux collectifs du risque sur les plans politiques, scientifiques, énergétiques, juridiques et éthiques. Puisse-t-il nourrir la réflexion sur la culture et la prévention du risque. Ses formes épidémiques, écologiques, sociales, terroristes et militaires nourrissent les peurs actuelles, structurent les projets sécuritaires et constituent - sans doute - les défis majeurs à notre modernité. Dans la foulée de la richesse scientifique d'Equinoxe, L'ÉQUINOXE hérite de son esprit en prenant à son tour le pari de contribuer - non sans risque - à enrichir en Suisse romande et ailleurs le champ éditorial des sciences humaines dont notre société a besoin pour forger ses repères. Après Face au risque suivra cet automne Du sens des Lumières. (MICHEL PORRET Professeur Ordinaire à la F...

  8. Bernard Maris, Anti-Manuel d'Economie, Bréal, 2003, 359p.

    Directory of Open Access Journals (Sweden)

    Jean Zin

    2004-02-01

    Full Text Available "Il doit être clair au terme de cet Antimanuel que la gratuité et la solidarité font la croissance, l'invention de la richesse malgré la concurrence, essentiellement inefficace". p.349Après l'Antimanuel de philosophie confié à Michel Onfray, les éditions Bréal publient un Antimanuel d'économie par Bernard Maris (l'oncle Bernard de Charlie-Hebdo. En fait, la forme est relativement proche de celle d'un manuel. Ce qui justifie le titre d'Antimanuel, c'est plutôt de dire le contraire de ce que d...

  9. Microwave surface resistance of bulk YBa2Cu3O6+x material

    Science.gov (United States)

    Fathy, A.; Kalokitis, D.; Belohoubek, E.; Sundar, H. G. K.; Safari, A.

    1988-10-01

    Superconducting Y-Ba-Cu-O samples were prepared by conventional solid-state reaction. The microwave surface resistance of 1:2:3 compound superconductor material was measured in a special disk resonator structure at 10 GHz. At liquid-nitrogen temperatures the microwave surface resistance is comparable to that of Au. At lower temperature (~10 K) the surface resistance is an order of magnitude lower than that of Au at the same temperature.

  10. PHENIX results on fluctuations and Bose-Einstein correlations in Au + Au collisions from the RHIC Beam Energy Scan

    Science.gov (United States)

    Garg, Prakhar

    2016-12-01

    The RHIC Beam Energy Scan focuses on mapping the QCD phase diagram and pinpointing the location of a possible critical end point. Bose-Einstein correlations and event-by-event fluctuations of conserved quantities, measured as a function of centrality and collision energy, are promising tools in these studies. Recent lattice QCD and statistical thermal model calculations predict that higher-order cumulants of the fluctuations are sensitive indicators of the phase transition. Products of these cumulants can be used to extract the freeze-out parameters [A. Bazavov et al., Phys. Rev. Lett. 109, 192302 (2012)] and to locate the critical point [M. A. Stephanov, K. Rajagopal and E. V. Shuryak, Phys. Rev. D 60, 114028 (1999)]. Two-pion interferometry measurements are predicted to be sensitive to potential softening of the equation of state and prolonged emission duration close to the critical point [S. Pratt, Phys. Rev. Lett. 53, 1219 (1984)]. We present recent PHENIX results on fluctuations of net-charge using high-order cumulants and their products in Au+Au collisions at √{sNN} = 7.7- 200 GeV, and measurement of two-pion correlation functions and emission-source radii in Cu+Cu and Au+Au collisions at several beam energies. The extracted source radii are compared to previous measurements at RHIC and LHC in order to study energy dependence of the specific quantities sensitive to expansion velocity and emission duration. Implications for the search of a critical point and baryon chemical potentials at various collision energies are discussed.

  11. Exploring Polaronic, Excitonic Structures and Luminescence in Cs4PbBr6/CsPbBr3.

    Science.gov (United States)

    Kang, Byungkyun; Biswas, Koushik

    2018-02-15

    Among the important family of halide perovskites, one particular case of all-inorganic, 0-D Cs 4 PbBr 6 and 3-D CsPbBr 3 -based nanostructures and thin films is witnessing intense activity due to ultrafast luminescence with high quantum yield. To understand their emissive behavior, we use hybrid density functional calculations to first compare the ground-state electronic structure of the two prospective compounds. The dispersive band edges of CsPbBr 3 do not support self-trapped carriers, which agrees with reports of weak exciton binding energy and high photocurrent. The larger gap 0-D material Cs 4 PbBr 6 , however, reveals polaronic and excitonic features. We show that those lattice-coupled carriers are likely responsible for observed ultraviolet emission around ∼375 nm, reported in bulk Cs 4 PbBr 6 and Cs 4 PbBr 6 /CsPbBr 3 composites. Ionization potential calculations and estimates of type-I band alignment support the notion of quantum confinement leading to fast, green emission from CsPbBr 3 nanostructures embedded in Cs 4 PbBr 6 .

  12. Synthesis and infrared characterization of Br-HBr and Br-DBr entrance channel complexes in solid parahydrogen.

    Science.gov (United States)

    Kettwich, Sharon C; Pinelo, Laura F; Anderson, David T

    2008-09-28

    We report high resolution vibrational spectra in the HBr (2560 cm(-1)) and DBr (1840 cm(-1)) stretching regions for Br-HBr and Br-DBr entrance channel complexes isolated in solid parahydrogen (pH2). The Br-HBr complexes are generated by synthesizing solid pH2 crystals doped with trace amounts of HBr/Br2 mixtures followed by 355 nm in situ photodissociation of Br2 to form Br atoms. After photolysis is complete, the solid is warmed from 2 to 4.3 K resulting in the irreversible formation of Br-HBr complexes. The large 36.63 cm(-1) HBr monomer-to-complex induced vibrational shift to lower energy measured in these studies is consistent with the linear Br-HBr hydrogen bonded structure predicted from theory. The 0.02 cm(-1) Br-HBr absorption linewidths indicate a 1 ns vibrational excited state lifetime for these entrance channel complexes in solid pH2.

  13. Elimination of nonspecific radioactivity from [{sup 76}Br]bromide in PET study with [{sup 76}Br]bromodeoxyuridine

    Energy Technology Data Exchange (ETDEWEB)

    Li Lu; Bergstroem, Mats E-mail: Mats.Bergstroem@pet.uu.se; Fasth, Karl-Johan; Wu Feng; Eriksson, Barbro; Laangstroem, Bengt

    1999-10-01

    [{sup 76}Br]Bromodeoxyuridine ([{sup 76}Br]BrdU) might allow a determination of proliferation in vivo using positron emission tomography (PET), but only with consideration of organ nonspecific radioactivity constituted by [{sup 76}Br]bromide. A first study assessed the potential of diuretics to eliminate [{sup 76}Br]bromide. [{sup 76}Br]Bromide was injected in the vein of rats and different diuretic combinations were given. Urine was collected and radioactivity measured. Torasemide plus sodium chloride gave better {sup 76}Br elimination than the other diuretics. In a second experiment, rats were given [{sup 76}Br]BrdU. After the radioactivity injection, the rats of the treatment group were given torasemide plus NaCl. At 44 h after the radioactivity injection, the radioactivity concentration and the fraction incorporated into DNA were measured in different organs. Using diuretics, the elimination of [{sup 76}Br]bromide was increased. The radioactivity decreased 30-50% in most of the organs but the highest radioactivity uptake was found in the organs with more active DNA synthesis. This method may facilitate the use of [{sup 76}Br]BrdU as a tracer for DNA synthesis using PET.

  14. Chiral magnetic effect search in p+Au, d+Au and Au+Au collisions at RHIC

    Science.gov (United States)

    Zhao, Jie; STAR Collaboration

    2017-09-01

    The chiral magnetic effect (CME) is a fundamental property of QCD. A major background source for CME measurements is the intrinsic particle correlations (such as resonances/jets decay) coupled with the azimuthal elliptical anisotropy v2. In heavy-ion collisions, the magnetic field direction and event plane azimuthal angle Ψ2 are correlated, thus the CME and the v2-induced background are entangled. In small system p+Au and d+Au collisions, the Ψ2 is mostly due to geometry fluctuations, and thus magnetic field direction and Ψ2 are uncorrelated. The correlation measurements in small system collisions with respect to Ψ2 are only sensitive to v2-induced background while any CME is averaged to zero. In this talk, we will present the STAR measurements of two-particle correlations with respect to Ψ2 in p+Au, d+Au and Au+Au collisions at √{sNN} = 200 GeV. These results are analyzed as a function of particle multiplicity to shed light on the background contaminations of the CME measurements in heavy-ion collisions. We will also report results from a new analysis approach as a function of the particle pair invariant mass in order to suppress non-CME related physics backgrounds.

  15. Cultura e biodiversidade: uma comparação entre a gestão do Parque Nacional do Cabo Orange, no Brasil, e a do Parque Nacional da Vanoise, na França Culture et biodiversité: une comparaison entre la gestion du Parc National Cabo Orange, au Brésil, et celle du Parc National de la Vanoise, en France Culture and biodiversity: a comparison between the management of Cabo Orange National Park, in Brazil and Vanoise National Park, in France

    Directory of Open Access Journals (Sweden)

    Nádia Bandeira Sacenco Kornijezuk

    2012-11-01

    Full Text Available Este artigo tem como objetivo comparar a gestão de dois parques nacionais: o Parque Nacional do Cabo Orange, no Brasil, e o Parque Nacional da Vanoise, na França. As regiões onde estão localizados esses dois parques nacionais - Amazônia e Alpes, respectivamente - têm um capital ecológico de importância global. O parque Nacional do Cabo Orange é apresentado sob o enfoque do seu contexto regional, das suas particularidades sociais e ambientais e do turismo. O parque Nacional da Vanoise é analisado sob o enfoque do turismo e dos determinantes históricos e geográficos da região onde ele se insere. A comparação entre a gestão do Parque Nacional da Vanoise e a do Parque Nacional do Cabo Orange mostra que tanto seus modelos de gestão quanto seus contextos geopolíticos e ambientais são diversos: a França é mais populosa e sua biodiversidade é antropizada. Já o Brasil é um país de espaços abertos onde a biodiversidade é, em grande parte, resultado do processo evolutivo natural. A metodologia utilizada baseou-se no trabalho de campo e na revisão bibliográfica da literatura. Conclui-se que o Parque Nacional da Vanoise tem sua gestão direcionada à tentativa de conciliação entre o desenvolvimento regional e a preservação dos patrimônios natural e cultural enquanto o Parque Nacional do Cabo Orange é protetor da biodiversidade em sua forma mais prístina possível.L’objectif de cet article consiste à comparer la gestion de deux parcs nationaux : le Parc National de Cabo Orange, au Brésil, et le Parc National de la Vanoise, en France. Les régions dans lesquelles se situent ces deux parcs nationaux – l’Amazonie et les Alpes, respectivement – présentent un capital écologique d’importance globale. Le Parc National de Cabo Orange est présenté sous la perspective de son contexte régional, de ses particularités sociales, environnementales et touristiques. L’analyse du Parc National de la Vanoise traite la

  16. Corrosion related iron oxides: Cu, Mn and Cr doped hematite

    Directory of Open Access Journals (Sweden)

    Pérez, G.

    2003-12-01

    Full Text Available We have obtained Cu, Mn, and Cr doped hematites, by a thermal treatment of doped goethites at 500 and 880 °C in air for 24 h. The goethites were prepared in the laboratory from iron chloride solutions in the presence of Cu2+, Mn2+, and Cr3+ ions. The samples are characterized by Mössbauer spectroscopy and X-ray diffraction. It is found that at 500 °C all the goethites have transformed into hematites. However, the thermal treatment at 880 °C produces hematites with better crystallinity.<br>>Hemos obtenido hematitas dopadas con Cu, Mn y Cr, por un tratamiento térmico de goethitas dopadas a 500 y 880 °C en aire durante 24 h. Las goethitas fueron preparadas en el laboratorio a partir de soluciones de cloruro de hierro en presencia de iones de Cu2+, Mn2+ y Cr3+. Las muestras fueron caracterizadas por espectroscopia Mössbauer y difracción de rayos X. Se encontró que a 500 °C todas las goethitas se han transformado a hematitas. Sin embargo, el tratamiento térmico a 880 °C produce hematitas con mejor cristalinidad.

  17. Transition metal complexes with thiosemicarbazide-based ligands. Part 60. Reactions of copper(II bromide with pyridoxal S-methylisothiosemicarbazone (PLITSC. Crystal structure of [Cu(PLITSC−HH2O]Br•H2O

    Directory of Open Access Journals (Sweden)

    Leovac Vukadin M.

    2014-01-01

    Full Text Available The synthesis and structural characterization of a square-planar copper(II complex with pyridoxal S-methylisothiosemicarbazone (PLITSC of the formula [Cu(PLITSC−HH2O]Br•H2O (1 as the first Cu(II complex with monoanionic form of this ligand were described. Complex 1 together with two previously synthesized complexes [Cu(PLITSCBr2] (2 and [Cu(PLITSCBr(MeOH]Br (3 were characterized by elemental analysis, IR and electronic spectra and also by the methods of thermal analysis, conductometry and magnetochemistry. [Projekat Pokrajisnkog sekretarijata za nauku i tehnoloski razvoj Vojvodine i Ministarstva nauke Republike Srbije, br. 172014

  18. On the evolution of Dipodium R. Br.

    Directory of Open Access Journals (Sweden)

    Peter O'byrne

    2014-12-01

    Full Text Available Dipodium R. Br. (Orchidaceae, a genus of ca. 38 species, should be divided into an Australasian clade and a Malesian clade, based on morphological and geographic evidences. Dipodium section Dipodium and section Leopardanthus (Blume O. Kuntze are re-defined to accommodate this change. An evolutionary scenario that explains this division is proposed. The lack of diversity of floral structure in the genus is probably caused by pollinator-specificity, while the diversity of plant form may be due to long-term environmental factors. An evolutionary explanation is suggested for the complex between Dipodium fevrellii J. J. Sm. and the hybrid D. pandanum Bailey in New Guinea. The complex in Java involving          D. pictum (Lindl. Rchb. f. and D. scandens (Bl. J. J. Sm. is discussed, and the presence of a hybrid noted. In Borneo, the complex taxonomic situation caused by repeated inter-breeding of populations is noted. 

  19. Supramolecular assembly of biphenyl dicarboxylic acid on Au(1 1 1)

    Science.gov (United States)

    Zhu, N.; Osada, T.; Komeda, T.

    2007-04-01

    We investigate the structure of submonolayer film of 4,4'-biphenyl dicarboxylic acid (BDA) molecules on Au(1 1 1)-22 × √3 reconstructed surface with the use of scanning tunneling microscopy (STM). The BDA molecules form ordered structures on Au(1 1 1) surface which are commensurate with the substrate. We have concluded that the molecule-molecule interaction is mainly through hydrogen bonding formed by a straight dimer of BDA molecules. The straight dimer can be expressed as 4 s + 2 t or its six crystallographic equivalents using the unit vectors of the gold substrate of s and t. The length of hydrogen bonding (O-H-O) is estimated to be 0.31 nm assuming nearest neighbor distance of gold atoms of 0.275 nm. The ordering shows a clear contrast with the case of BDA on Cu(1 0 0) surface [S. Stepanow, N. Lin, F. Vidal, A. Landa, M. Ruben, J.V. Barth, K. Kern, Nanoletters 5 (2005) 901] in which a square type of ordering of molecules is observed by the formation of hydrogen bonding between a carboxylate (COO) and a benzene ring. The clear difference of the ordered structure on Cu(1 0 0) and Au(1 1 1) surface demonstrates that the absence (presence) of deprotonation of carboxyl group of BDA molecule on Au(1 1 1) (Cu(1 0 0)) switches the straight and square type ordering of BDA molecules.

  20. Inhibition of tumor angiogenesis by Brahma Rasayana (BR).

    Science.gov (United States)

    Thangapazham, Rajesh L; Sharma, Anuj; Gaddipati, Jaya P; Singh, Anoop K; Maheshwari, Radha K

    2006-01-01

    The current therapy for prostate cancer includes radical prostatectomy, radiation therapy and hormonal ablation. Chemotherapy also provides beneficial results for some patients with advanced prostate cancer but with several harmful side effects. Hence there is a need to identify and develop alternate therapies, which can reduce the disease progression with minimal or few side effects. Earlier studies from our laboratory have shown that a Polyherbal mixture, Brahma Rasayna (BR) rich in anti-oxidant principles has a potential to be an anti-tumor agent. BR treatment of MAT-LyLu cell inoculated Copenhagen rats resulted in a decrease of palpable tumor incidence, delay in tumor occurrence and lower mean tumor volumes. Also, a significant reduction in tumor weight and lung metastasis was observed in BR treated animals in comparison to untreated controls. In the present study, we focused to examine the effect of BR on angiogenesis and regulation of molecular markers involved in angiogenesis using in-vivo and in-vitro models. BR treatment showed a significant reduction in Factor VIII expression compared to control indicating reduced angiogenesis. BR treated tumor specimens showed a decrease in the pro-angiogenic factors like VEGF, MMP-9 and MMP-2. Methanolic extract of BR was found to inhibit the proliferation, tube formation, cell migration and attachment of HUVEC on matrigel in a dose dependant manner. These findings suggest the possible mechanism(s) of action of BR in the reduction of tumor growth and metastatic spread.

  1. Optimisation of the microstructure of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} superconducting ceramics textured by horizontal solidification. Effects of a magnetic field applied vertically during the solidification process; Optimisation de la microstructure de ceramiques supraconductrices texturees YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} par solidification horizontale. Effets de l`application d`un champ magnetique vertical au cours de la croissance

    Energy Technology Data Exchange (ETDEWEB)

    Durand, L.

    1995-12-14

    We have shown that il was possible to disperse in a very homogeneous way, into the 123 matrix, 211 particles regular in size around 1{mu}m, by directional solidification of a mixture of 123 plus 211 sol-gel powders. The addition of 0.5 wt% of Pt lo this precursor mixture has permitted us to refine further the size of the 211 particles. Moreover, we have established that the finer the 123 powder and the faster the heating rate, the smaller the 211 particles. From another hand, we have found that the size and the microstructure of the solidified single domain was dependant upon numerous parameters. In particular, we have noted that if the cold pressed green body was not sintered before being melted, grains of solid CuO appeared into the liquid which next hardly recombined with it, giving rise to a comb like solidification front, witness of a local un-stability. Moreover, in these particular conditions, the 123 formed was found to be understoichiometric in Cu and the single domains severely limited in extension. Finally, we have observed that the application of a 4 T magnetic field during the solidification of a bar the longest axis of which was horizontal tended to align the c axis of the 123 grains parallel to the field. Incidentally, we have discovered that in the same conditions, the 211 particles trapped into the 123 matrix were also preferentially oriented. (author).

  2. Rhodamine B immobilized on hollow Au-HMS material for naked-eye detection of Hg2+ in aqueous media.

    Science.gov (United States)

    Zhang, Na; Li, Gang; Cheng, Zhuhong; Zuo, Xiujin

    2012-08-30

    A simple, effective method has been demonstrated to immobilize Rhodamine B (RhB) probes on mesoporous silica (Au-HMS). The prepared chemosensor (Au-HMS-Probe) was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), UV-vis spectrum and Fourier transform infrared spectroscopy (FT-IR). Further application of Au-HMS-Probe in sensing Hg(2+) was confirmed by fluorescence titration experiment. Au-HMS-Probe afforded "turn-on" fluorescence enhancement and displayed high brightness in water, and it also showed excellent selectivity for Hg(2+) over alkali (Na(+), K(+)), alkaline earth (Mg(2+), Ca(2+)) and other heavy metal ions (Ag(+), Cd(2+), Co(2+), Pb(2+), Ni(2+), Cu(2+), Fe(2+)). Importantly, Au-HMS-Probe could be regenerated by treatment with tetrapropylammonium hydroxide solution. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  3. Corrosion inhibition performance of a ionic liquid surfactant Br

    Directory of Open Access Journals (Sweden)

    Jing LIU

    2016-02-01

    Full Text Available In order to study the novel green organic mercury-substituting inhibitors, the ionic liquid surfactant 1-methyl-3-dodecyl imidazole bromide ( Br is synthesized with N-methyl imidazole and 1-bromodecane as raw materials. The corrosion inhibition of Br for zinc in zinc-manganese batteries is investigated using electrochemical methods and weight loss methods. The results show that corrosion inhibition efficiency increases with the increase of the concentration of Br, and when the concentration is higher than 8×10-3 mol/L, the inhibition efficiency tends to be stable. The polarization curve shows that Br belongs to mixed-type corrosion inhibitor. The thermodynamic parameters show that Br is spontaneously adsorbed on the zinc surface, forming a monomolecular adsorption layer, which fits with Langmuir adsorption isotherm with physical and chemical adsorption mechanism.

  4. Group IB Organometallic Chemistry XIX.Synthesis and characterization of mixed-organocopper cluster compounds R4R'2Cu6 containing aryl and acetylide ligands.

    NARCIS (Netherlands)

    Koten, G. van; Hoedt, R.W.M. ten; Noltes, J.G.

    1977-01-01

    Mixed-organocopper cluster compounds Ar4Cu6(CCR)2 (Ar = 2-Me2NC6H4, R = phenyl, 4-tolyl, 2,4-xylyl or mesityl) have been prepared in high yield by the ligand-substitution reaction of Ar4Cu6Br2 with two equivalents of LiCCR. Ar4Cu6(CCC6H4CH3-4)2 has also been prepared via the aryl¡ªarylacetylide

  5. Fabrication of fine spongy nanoporous Ag-Au alloys with improved catalysis properties

    Directory of Open Access Journals (Sweden)

    Cuiting Li

    2017-12-01

    Full Text Available Fine NP-AgAu (nanoporous AgAu alloys with spongy structure was fabricated by chemical dealloying from rapidly solidified amorphous precursors Ag38.75−xCu38.75Si22.5Aux (x=0, 0.5, 1 and 5. The results indicate that the addition of small content Au in precursor can refine both the ligaments and pores obviously. Among the present components of the precursors, NP-AgAu alloys dealloying from Ag37.75Cu38.75Si22.5Au1 had the finest spongy structure. The size of pores was 5–10 nm and the grain size of ligaments was 10–20 nm. It also had the highest surface area of 106.83 m2g−1 and the best catalytic activity towards electro-oxidation of formaldehyde with the peak current of 665 mA mg−1.

  6. Bimolecular two-dimensional organization of porphyrins on Au(111): site selective, metal ion-dependent adsorption of tetraphenylporphyrin.

    Science.gov (United States)

    Suto, Koji; Yoshimoto, Soichiro; Itaya, Kingo

    2009-01-01

    Adlayers consisting of two components selected from the group of cobalt(II) tetraphenylporphyrin (CoTPP), copper(II) tetraphenylporphyrin (CuTPP), and zinc(II) tetraphenylporphyrin (ZnTPP) were prepared by immersing Au(111) substrate in a benzene solution containing those molecules. The bimolecular adlayers thus prepared were investigated in 0.1 M HClO4 by electrochemical scanning tunneling microscopy (EC-STM). The mixed adlayers consisting of CoTPP and CuTPP formed structurally ordered but compositionally disordered arrays on Au(111). The ratio of CoTPP to CuTPP molecules in the mixed adlayer was proportional to the ratio of CoTPP to CuTPP molecules in the solution phase. Accordingly, the composition of CoTPP and CuTPP in the adlayer on the Au(111) surface was independent of absolute concentrations of these species in the solution and immersion time. In contrast, the structural feature of the mixed adlayer consisting of CoTPP and ZnTPP was similar to that of the mixed adlayer of CoTPP and CuTPP when these adlayers were prepared in solutions containing those mixtures at a total concentration of 100 microM, whereas when the total concentration was lower, adsorption was site-selective depending on the coordinated metal ion. This finding indicates that the herringbone structure of reconstructed Au(111) served as a template for the bimolecular assembly of CoTPP and ZnTPP. The characteristic phase separation of CoTPP and ZnTPP molecules assisted by reconstructed Au(111) surface can be controlled by the subtle balance between kinetics and thermodynamics.

  7. Brändikäsikirjan toteutus Yritys X:n brändin rakentamisen tueksi

    OpenAIRE

    Ahokas, Riikka

    2017-01-01

    Tämän opinnäytetyön tavoitteena oli luoda toimeksiantajayritykselle yhdenmukainen ja kilpailijoista erottuva brändi. Tarkoituksena oli siis selvittää, minkälainen brändi kuvaa yritystä parhaiten sekä eroaa riittävästi yrityksen kilpailijoista. Tämän lisäksi selvitettiin, millainen on hyvä brändikäsikirja. Toimeksiantajayrityksen on tarkoitus käyttää brändikäsikirjaa henkilöstönsä perehdytyksessä. Teoreettisessa viitekehyksessä käsitellään brändiä, sen tärkeimpiä tehtäviä sekä sen merkitys...

  8. Kinetics of the reactions of HBr with O3 and HO2: The yield of HBr from HO2 + BrO

    Science.gov (United States)

    Mellouki, Abdelwahid; Talukdar, Ranajit K.; Howard, Carleton J.

    1994-01-01

    An upper limit on the yield of HBr from reaction (R1) (HO2 + BrO yields products) has been determined by measuring an upper limit for the rate coefficient of the reverse reaction (R1') (HBr + O3 yields HO2 + BrO). The limits measured at 300 and 441 K were extrapolated to low temperatures to determine that the yield of HBr from reaction (R1) is negligible throughout the stratosphere (less than 0.01% of k(sub 1)). An upper limit for the rate coefficient of the reaction of HO2 with HBr was also determined to be very low less than or equal to 3 x 10(exp -17) cu cm/molecule/sec at 300 K and less than or equal to 3 x 10(exp -16) cu cm/molecule/sec at 400 K. The implications of these results to stratospheric chemistry are discussed.

  9. Borophene synthesis on Au(111)

    Science.gov (United States)

    Guisinger, Nathan; Kiraly, Brian; Zhang, Zhuhua; Mannix, Andrew; Hersam, Mark C.; Yakobson, Boris I.

    The recent experimental discovery of borophene, the metallic 2-dimensional allotrope of boron, has sparked tremendous interest in further exploration of this unique material. The initial synthesis of borophene was accomplished on Ag substrates and serves as a quintessential example of predictive modeling to experimental realization. In this talk, we expand the phase-space of borophene synthesis to Au. Borophene synthesis was accomplished by evaporating elemental boron onto a Au(111) substrate. The synthesized borophene retains its metallic character on Au as verified with scanning tunneling spectroscopy. Most fascinating is the difference in growth dynamics on the Au(111) substrate where the reconstructed surface presents a unique energy landscape for borophene nucleation and growth. We find that the initial low-coverage growth of borophene modifies the herringbone reconstruction into a ``trigonal'' network, where the 2D boron islands are uniformly templated across the surface. Increasing coverage results in the increasing size of the templated borophene islands until they coalesce into larger sheets. The observed growth dynamics are supported by the computational modeling of boron nucleation on Au.

  10. L’apprentissage au cern

    CERN Multimedia

    2007-01-01

    pour les professions d’électronicien(ne) et de laborantin(e) en physique L’apprentissage au CERN est régi par les lois, règlements et contrats en vigueur dans le canton de Genève. En cas de réussite à l’examen de fin d’apprentissage, les apprentis obtiennent le Certificat fédéral de capacité suisse (CFC). 6 places au total sont ouvertes au recrutement pour les deux professions. L’apprentissage dure 4 ans. Minima requis pour faire acte de candidature : avoir au moins 15 ans et moins de 21 ans à la date de début de l’apprentissage ; avoir terminé la scolarité obligatoire, au minimum 9e du Cycle d’orientation genevois (3e en France) ; être ressortissant d’un pays membre du CERN (Allemagne, Autriche, Belgique, Bulgarie, Danemark, Espagne, Finlande, France, Grèce, Hongrie, Italie, Norvège, Pays-Bas, Pologne, Portugal, Royaume-Uni, République tchèque, République slovaque , Suède, Suisse) ; pour les résidents en Suisse : être ressortissant su...

  11. Transverse Velocity Scaling in Au+Au Fragmentation

    OpenAIRE

    Lukasik, J.; Hudan, S.; Lavaud, F.; Turzo, K.; Auger, G.; Bacri, Ch.O.; Begemann-Blaich, M.L.; Bellaize, N.; Bittiger, R.; Bocage, F.; Borderie, B.; Buchet, P.; R. Bougault(LPCC); Bouriquet, B.; Charvet, J. L.

    2002-01-01

    Invariant transverse-velocity spectra of intermediate-mass fragments were measured with the 4-pi multi-detector system INDRA for collisions of Au on Au at incident energies between 40 and 150 MeV per nucleon. Their scaling properties as a function of incident energy and atomic number Z are used to distinguish and characterize the emissions in (i) peripheral collisions at the projectile and target rapidities, and in (ii) central and (iii) peripheral collisions near mid-rapidity. The importance...

  12. Trématodes parasites de poissons marins du littoral de Rio de Janeiro, Brésil

    Directory of Open Access Journals (Sweden)

    Martine Wallet

    1987-03-01

    Full Text Available Les Trématodes de 35 espèces de poissons marins, d'importance commerciale, collectés dans le littoral de Rio de Janeiro, ont été étudiés. Dix-sept espèces de Trématodes appartenant à 13 familles ont été recensées. Quatre de ces espèces sont référés pour la première fois au Brésil: Diphtherostomum americanum, Diplomonorchis floridensis, Pancreadium otagoensis et Neomegasolena chaetodipteri, neuf dans de nouveaux hôtes: D. americanum, Diplangus paxillus, Hurleytrema shorti, Lecithochirium microstomum, Morascus filiformis, Neolebouria multilobatus, P. otagoensis, Pleorchis mollis et Opechona bacillaris, une a été recontrée dans un hôte mentionné pour la première fois au Brésil: Vitellibaculum spinosum et cinq autres espècies sont déjà répertoriées: Acanthocollaritrema umbilicatum, Bucephalopsis calliocotyle, Bucephalus varicus, Parahemiurus merus et Tergestia pauca. Tergestia selenei est consideré synonyme de T. pauca. Les principales mesures sont données pour chaque espèce.

  13. Equilibrium reconstruction in the TCA/Br tokamak; Reconstrucao do equilibrio no tokamak TCA/BR

    Energy Technology Data Exchange (ETDEWEB)

    Sa, Wanderley Pires de

    1996-12-31

    The accurate and rapid determination of the Magnetohydrodynamic (MHD) equilibrium configuration in tokamaks is a subject for the magnetic confinement of the plasma. With the knowledge of characteristic plasma MHD equilibrium parameters it is possible to control the plasma position during its formation using feed-back techniques. It is also necessary an on-line analysis between successive discharges to program external parameters for the subsequent discharges. In this work it is investigated the MHD equilibrium configuration reconstruction of the TCA/BR tokamak from external magnetic measurements, using a method that is able to fast determine the main parameters of discharge. The thesis has two parts. Firstly it is presented the development of an equilibrium code that solves de Grad-Shafranov equation for the TCA/BR tokamak geometry. Secondly it is presented the MHD equilibrium reconstruction process from external magnetic field and flux measurements using the Function Parametrization FP method. this method. This method is based on the statistical analysis of a database of simulated equilibrium configurations, with the goal of obtaining a simple relationship between the parameters that characterize the equilibrium and the measurements. The results from FP are compared with conventional methods. (author) 68 refs., 31 figs., 16 tabs.

  14. Chlorination of iodide-containing waters in the presence of CuO: Formation of periodate

    KAUST Repository

    Liu, Chao

    2014-11-18

    It has been shown previously that the disproportionation of halogen-containing oxidants (e.g., HOCl, HOBr, and ClO2) is enhanced by a CuO-catalyzed process. In this study, the transformation of iodine during chlorination in the presence of CuO was investigated. There is no significant enhancement of the disproportionation of hypoiodous acid (HOI) in the presence of CuO. The formation rate of iodate (IO3 -) in the CuO-HOCl-I- system significantly increased when compared to homogeneous solutions, which was ascribed to the activation of HOCl by CuO enhancing its reactivity toward HOI. In this reaction system, iodate formation rates increase with increasing CuO (0-0.5 g L-1) and bromide (0-2 μM) doses and with decreasing pH (9.6-6.6). Iodate does not adsorb to the CuO surfaces used in this study. Nevertheless, iodate concentrations decreased after a maximum was reached in the CuO-HOCl-I-(-Br-) systems. Similarly, the iodate concentrations decrease as a function of time in the CuO-HOCl-IO3 - or CuO-HOBr-IO3 - system, and the rates increase with decreasing pH (9.6-6.6) due to the enhanced reactivity of HOCl or HOBr in the presence of CuO. It could be demonstrated that iodate is oxidized to periodate by a CuO-activated hypohalous acid, which is adsorbed on the CuO surface. No periodate could be measured in filtered solutions because it was mainly adsorbed to CuO. The adsorbed periodate was identified by scanning electron microscopy plus energy dispersive spectroscopy and X-ray photoelectron spectroscopy.

  15. La Alpaca -vaatemerkin brändäys

    OpenAIRE

    Lehtinen, Laura

    2013-01-01

    Tämä opinnäytetyö käsittelee brändin vahvistamista ja brändiohjeiston luomista vaa-tealan yritykselle La Alpacalle. La Alpaca on suomalainen vaatemerkki, joka suunnit-telee, tuottaa ja myy alpakanvillasta valmistettuja tuotteita. Materiaalin ainutlaatuisuus ja hienous ovat olleet osa yrityksen identiteettiä alusta asti. Brändin lisäksi työssä on tutkittu kaupankäynnin rakenteellista muuttumista perinteisestä myymälätoiminnasta verkkomyyntiin. Työn tavoitteena on ollut luoda materiaalin tun...

  16. A questão da participação da comunidade do Distrito de Perus-(São Paulo/Brasil, no projeto MDL Aterro Bandeirantes La question de la participation communautaire dans le district de Perus, (São Paulo / Brésil, au projet MDL Aterro Bandeirantes The issue of community participation in the MDL Aterro Bandeirantes project, District of Perus, São Paulo / Brazil

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Rizzi

    2011-03-01

    petit quartier appelé Perus, dans la zone ouest de São Paulo. Malgré la recommandation des experts et la volonté de la communauté locale d'implanter un parc sur le site d'enfouissement, la municipalité a opté pour une finalité économique: la production d'électricité par combustion de gaz méthane émanant de la décomposition des déchets accumulés. Depuis 2003, avec Unibanco en tant que médiateur en chef, elle a poussé au déploiement,sur l'aire d'enfouissement, d'un projet MDL - Mécanisme de Développement Propre. Ce projet est un instrument opérationnel du Protocole de Kyoto qui appelait à la réduction des émissions de polluants dans l'atmosphère par l'encouragement de pratiques économiques qui génèrent de l'énergie alternative propre et qui vise à convertir les crédits de carbone (certifié en actifs financiers. La proposition serait une excellente idée pour tous les acteurs concernés, si les autorités municipales n'avaient pas oublié d'appeler la communauté locale à participer à la conduite du projet, ce qui est prévu par l'Article 2 de ce traité. Le texte analyse la façon dont la participation locale a été écartée de la conduite du projet et comment a été formé un monopole des grands acteurs hégémoniques dans la capture, la production, la distribution et la consommation d'électricité produite par une activité lucrative alternative, le Consórcio Bandeirantes, qui rassemble des entreprises du Projeto MDL Aterro Bandeirantes.From 2001 began the questioning of municipal government, civil society and experts about the future of the Aterro Bandeirantes, the world's largest landfill, located in a small district called Perus, in the western zone of São Paulo. Although the recommendation of experts and the will of the local community to create a park on the landfill, the municipal government has opted for an economic finality: the generation of electricity by burning methane gas emanating from the decomposition of

  17. Multiscale Modeling of Au-Island Ripening on Au(100

    Directory of Open Access Journals (Sweden)

    Karin Kleiner

    2011-01-01

    Full Text Available We describe a multiscale modeling hierarchy for the particular case of Au-island ripening on Au(100. Starting at the microscopic scale, density functional theory was used to investigate a limited number of self-diffusion processes on perfect and imperfect Au(100 surfaces. The obtained structural and energetic information served as basis for optimizing a reactive forcefield (here ReaxFF, which afterwards was used to address the mesoscopic scale. Reactive force field simulations were performed to investigate more diffusion possibilities at a lower computational cost but with similar accuracy. Finally, we reached the macroscale by means of kinetic Monte Carlo (kMC simulations. The reaction rates for the reaction process database used in the kMC simulations were generated using the reactive force field. Using this strategy, we simulated nucleation, aggregation, and fluctuation processes for monoatomic high islands on Au(100 and modeled their equilibrium shape structures. Finally, by calculating the step line tension at different temperatures, we were able to make a direct comparison with available experimental data.

  18. Experimental and computational investigation of the group 11-group 2 diatomic molecules: first determination of the AuSr and AuBa bond energies and thermodynamic stability of the copper- and silver-alkaline earth species.

    Science.gov (United States)

    Ciccioli, A; Gigli, G; Lauricella, M

    2012-05-14

    The dissociation energies of the intermetallic molecules AuSr and AuBa were for the first time determined by the Knudsen effusion mass spectrometry method. The two species were produced in the vapor phase equilibrated with apt mixtures of the constituent elements, and the dissociation equilibria were monitored mass-spectrometrically in the temperature range 1406-1971 K (AuSr) and 1505-1971 K (AuBa). The third-law analysis of the equilibrium data gives the following dissociation energies (D(0)°, in kJ/mol): 244.4 ± 4.8 (AuSr) and 273.3 ± 6.3 (AuBa), so completing the series of D(0)°s for the AuAE (AE = group 2 element) diatomics. The AuAE species were also studied computationally at the coupled cluster including single, double and perturbative triple excitation [CCSD(T)] level with basis sets of increasing zeta quality, and various complete basis set limit extrapolations were performed to calculate the dissociation energies. Furthermore, the entire series of the heteronuclear diatomic species formed from one group 11 (Cu, Ag) and one group 2 (Be, Mg, Ca, Sr, Ba) metal was studied by DFT with the hybrid meta-GGA TPSSh functional and the def2-QZVPP basis set, selected after screening a number of functional-basis set combinations using the AuAE species as benchmark. Dissociation energies, internuclear distances, vibrational frequencies, and anharmonic constants were determined for the CuAE and AgAE species and their thermal functions evaluated therefrom. On this basis, a thermodynamic evaluation of the formation of these species was carried out under various conditions.

  19. Group IB Organometallic Chemistry XXXIV: Thermal behavior and chemical reactivity of tetranuclear Me2N-substituted diarylpropenylcopper-copper anion (Vi2Cu4X2) and mixed diarylpropenyl/organocopper (Vi2Cu4R2) compounds

    NARCIS (Netherlands)

    Koten, G. van; Hoedt, R.W.M. ten; Noltes, J.G.

    1980-01-01

    Thermal decomposition of configurationally pure 1, 2-diarylpropenylcopper compounds Z-Vi{2}CU{4}Br{2} and Z-Vi{2}Cu{4}R{2} [Vi @? (2-Me{2}NC{6}H{4})C@?C(Me)-(C{6}H{4}Me-4), R @? 2-Me{2}NC{6}H{4} or 4-MeC{6}H{4}C@?C] predominantly results in the formation of ViH. In contrast, only dimers (ViVi) were

  20. Hybridization of Single Nanocrystals of Cs4PbBr6 and CsPbBr3

    OpenAIRE

    Weerd, Chris de; Lin, Junhao; Gomez, Leyre; Fujiwara, Yasufumi; Suenaga, Kazutomo; Gregorkiewicz, Tom

    2017-01-01

    Nanocrystals of all-inorganic cesium lead halide perovskites (CsPbX3, X = Cl, Br, I) feature high absorption and efficient narrow-band emission which renders them promising for future generation of photovoltaic and optoelectronic devices. Colloidal ensembles of these nanocrystals can be conveniently prepared by chemical synthesis. However, in the case of CsPbBr3, its synthesis can also yield nanocrystals of Cs4PbBr6 and the properties of the two are easily confused. Here, we investigate in de...

  1. Elu Brüsselis - teisem kui siin / Juune Holvandus

    Index Scriptorium Estoniae

    Holvandus, Juune

    2000-01-01

    Brüsseli kesklinnas elavast noorpaarist ja nende kodust. Veronique Mägi (isa eestlane) on tõlk. Ettevõtja Frederic Flamand on õppinud antiigindust. 1996. a. elati Eestis. Inimsuhetest Eestis ja Belgias. 11 ill.

  2. GMO konverents Brüsselis / Nastja Pertsjonok

    Index Scriptorium Estoniae

    Pertsjonok, Nastja

    2007-01-01

    Brüsselis toimunud GMO-vabade piirkondade konverentsist, kus räägiti GMO-vabade piirkondade liikumisest, GMO-de lubamisest ja keelamisest ning hoiakutest nende suhtes Euroopa Liidus ja mujal maailmas

  3. Three novel Cu6S6 cluster-based coordination compounds: synthesis, framework modulation and the sensing of small molecules and Fe(3+) ions.

    Science.gov (United States)

    Song, Jiang-Feng; Li, Si-Zhe; Zhou, Rui-Sha; Shao, Jia; Qiu, Xiao-Min; Jia, Ying-Ying; Wang, Jun; Zhang, Xiao

    2016-08-07

    Three novel Cu6S6 cluster-based coordination compounds formulated as [Cu(mpymt)3]2 (1), {(CuBr4)[Cu(mpymt)6]}n (2), and {(CuI6)[Cu(mpymt)6]}n (3) (Hmpymt = 4-methylpyrimidine-2-thione), have been synthesized under solvothermal conditions and characterized by elemental analysis, infrared (IR) spectroscopy, thermal gravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. Structural analysis reveals that compound 1 shows a distorted octahedral core of six copper atoms (Cu6S6) constructed from four α and two β type N[double bond, length as m-dash]C-SH parts from six mpymt(-) anions. Compound 2 displays an interesting 3D framework constructed from Cu6S6 and Cu4Br4 Cu(i) clusters simultaneously, interestingly, six mpymt(-) with α type N[double bond, length as m-dash]C-SH parts are involved in the formation of Cu6S6. Compound 3 displays an infinite 1D framework constructed from Cu6S6 and Cu6I6 Cu(i) clusters, notably, four α and two β type N[double bond, length as m-dash]C-SH parts are involved in the formation of the Cu6S6 cluster, however, only mpymt(-) ligands containing α type N[double bond, length as m-dash]C-SH parts form the bridged Cu6I6 cluster. The experimental results reveal that halogen ions finely modulate the structural features of compounds 1-3. The fluorescent properties of compounds 1-3 in the solid state and in various solvent emulsions were investigated in detail, the results of which indicate that compounds 1-3 are all highly sensitive naked eye colorimetric sensors for NB, 2-NT and Fe(3+) (NB = nitrobenzene and 2-NT = 2-nitrotoluene).

  4. Ternary and quaternary oxides of Bi, Sr and Cu

    Science.gov (United States)

    Casais, M. T.; Millan, P.; Rasines, I.; Campa, J. A.

    1991-01-01

    Before the discovery of superconductivity in an oxide of Bi, Sr, and Cu, the system Bi-Sr-Cu-O had not been studied, although several solid phases had been identified in the two-component regions of the ternary system Bi2O3-Si-O-CuO. The oxides Sr2CuO3, SrCu2O2, SrCuO2, and Bi2CuO4 were then well known and characterized, and the phase diagram of the binary system Bi2O3-SrO had been established in the temperature range 620 to 1000 C. Besides nine solutions of compositions Bi(2-2x) Sr(x) O(3-2x) and different symmetries, this diagram includes three definite compounds of stoichiometries Bi(2)BrO4. Bi2Sr2O5, and Bi2Sr3O6 (x - 0.50, 0.67 and 0.75 respectively), only the second of which with known unit-cell of orthorhombic symmetry, dimensions (A) a = 14.293(2), b = 7.651(2), c = 6.172(1), and z = 4. The first superconducting oxide in the system Bi-Sr-Cu-O was initially formulated as Bi2Sr2Cu2O(7+x), with an orthorhombic unit-cell of parameters (A) a = 5.32, b = 26.6, c = 48.8. In a preliminary study the same oxide was formulated with half the copper content, Bi(2)Sr(2)CuO(6+x), and index its reflections assuming an orthorhombic unit-cell of dimensions (A) a = 5.390(2), b = 26.973(8), c = 24.69(4). Subsequent studies by diffraction techniques have confirmed the composition 2:2:1. A new family of oxygen-deficient perovskites, was characterized, after identifying by x ray diffraction the phases present in the products of thermal treatments of about 150 mixtures of analytical grade Bi2O3, Sr(OH)2-8H2O and CuO at different molar ratios. X ray diffraction data are presented for some other oxides of Bi and Sr, as well as for various quaternary oxides, among them an oxide of Bi, Sr, and Cu.

  5. Kan lignin omdannes til flydende brændstof?

    DEFF Research Database (Denmark)

    Nielsen, Joachim Bachmann; Jensen, Anders; Felby, Claus

    2015-01-01

    Ved en solvolytisk omdannelse af plantematerialet lignin til et flydende brændstof behandles det ved høj temperatur og højt tryk i et passende opløsningsmiddel. En sådan proces kan gennemføres ikke-katalytisk og være med til at skabe flydende brændsler baseret på vedvarende energikilder. Her...

  6. Saltindhold i brød og morgenmadscerealier

    DEFF Research Database (Denmark)

    Trolle, Ellen; Saxholt, Erling; Knuthsen, Pia

    2016-01-01

    Saltindholdet i hvedebrød og rugbrød på de danske supermarkedshylder er faldet fra 2009 til 2014. En tilsvarende trend er ikke registreret i brød fra bagerbutikker. Udviklingen betyder, at en større andel af industrielt fremstillede brød end bagerbrød indsamlet i 2014 overholder Nøglehulsmærkets ...... overstiger Nøglehulsmærkets saltkrav. Saltindholdet er dog faldet i forhold til tidligere....

  7. Structural verification and optical characterization of SiO2–Au–Cu2O ...

    Indian Academy of Sciences (India)

    Then, they were clung to the surface of Au seeds. The morphology of the resultant particles was studied using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Transmission electron microscopy images demonstrate growth of monodispersed gold seeds and Cu2O nanoparticles in narrow ...

  8. Direct jet reconstruction in p + p and Cu + Cu at PHENIX

    CERN Document Server

    Lai, Yue-Shi

    2009-01-01

    The Relativistic Heavy Ion Collider collides heavy nuclei at ultrarelativistic energies, creating a strongly interacting, partonic medium that is opaque to the passage of high energy quarks and gluons. Direct jet reconstruction applied to these collision systems provides a crucial constraint on the mechanism for in-medium parton energy loss and jet-medium interactions. However, traditional jet reconstruction algorithm operating in the large soft background at RHIC give rise to fake jets well above the intrinsic production rate of high-pT partons, impeding the detection of the low cross section jet signal at RHIC energies. We developed a new jet reconstruction algorithm that uses a Gaussian filter to locate and reconstruct the jet energy. This algorithm is combined with a fake jet rejection scheme that provides efficient jet reconstruction with acceptable fake rate in a background environment up to the central Au + Au collision at sqrt(s_NN) = 200 GeV. We present results of its application in p + p and Cu + Cu...

  9. Au36(SPh)23 nanomolecules.

    Science.gov (United States)

    Nimmala, Praneeth Reddy; Dass, Amala

    2011-06-22

    A new core size protected completely by an aromatic thiol, Au(36)(SPh)(23), is synthesized and characterized by MALDI-TOF mass spectrometry and UV-visible spectroscopy. The synthesis involving core size changes is studied by MS, and the complete ligand coverage by aromatic thiol group is shown by NMR.

  10. Density Functional Theory with Modified Dispersion Correction for Metals Applied to Self-Assembled Monolayers of Thiols on Au(111

    Directory of Open Access Journals (Sweden)

    M. P. Andersson

    2013-01-01

    Full Text Available Using sound physical principles we modify the DFT-D2 atom pairwise semiempirical dispersion correction to density functional theory to work for metallic systems and in particular self-assembled monolayers of thiols on gold surfaces. We test our approximation for two functionals PBE-D and revPBE-D for lattice parameters and cohesive energies for Ni, Pd, Pt, Cu, Ag, and Au, adsorption energies of CO on (111 surfaces of Pd, Pt, Cu, Ag, and Au, and adsorption energy of benzene on Ag(111 and Au(111. Agreement with experimental data is substantially improved. We apply the method to self-assembled monolayers of alkanethiols on Au(111 and find reasonable agreement for PBE-D and revPBE-D for both physisorption of n-alkanethiols as well as dissociative chemisorption of dimethyl disulfide as an Au-adatom-dithiolate complex. By modifying the C6 coefficient for Au, we obtain quantitative agreement for physisorption and chemisorption for both PBE-D and revPBE-D using the same set of parameters. Our results confirm that inclusion of dispersion forces is crucial for any quantitative analysis of the thiol and thiolate bonds to the gold surface using quantum chemical calculations.

  11. Effect of low energy electron irradiation on DNA damage by Cu{sup 2+} ion

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Hyung Ah; Cho, Hyuck [Dept. of Physics, Chungnam National University, Daejeon (Korea, Republic of); Park, Yeun Soo [Plasma Technology Research Center, National Fusion Research Institute, Gunsan (Korea, Republic of)

    2017-03-15

    The combined effect of the low energy electron (LEE) irradiation and Cu{sup 2+} ion on DNA damage was investigated. Lyophilized pBR322 plasmid DNA films with various concentrations (1–15 mM) of Cu{sup 2+} ion were independently irradiated by monochromatic LEEs with 5 eV. The types of DNA damage, single strand break (SSB) and double strand break (DSB), were separated and quantified by gel electrophoresis. Without electron irradiation, DNA damage was slightly increased with increasing Cu ion concentration via Fenton reaction. LEE-induced DNA damage, with no Cu ion, was only 6.6% via dissociative electron attachment (DEA) process. However, DNA damage was significantly increased through the combined effect of LEE-irradiation and Cu ion, except around 9 mM Cu ion. The possible pathways of DNA damage for each of these different cases were suggested. The combined effect of LEE-irradiation and Cu ion is likely to cause increasing dissociation after elevated transient negative ion state, resulting in the enhanced DNA damage. For the decrease of DNA damage at around 9-mM Cu ion, it is assumed to be related to the structural stabilization due to DNA inter- and intra-crosslinks via Cu ion.

  12. Synthesis and electron microscopy characterization of bimetallic nanoparticles and atomically controlled Au nanoclusters

    Science.gov (United States)

    Bhattarai, Nabraj

    The properties of metal nanoparticles are controlled by their composition, shape, size and crystalline structure. Nanoparticles and nanoclusters with controlled shape and size were synthesized and investigated using atomic resolution images from aberration corrected scanning/transmission electron microscopy (STEM) and mass spectrometry (MS). Gold-palladium (Au-Pd) core-shell nanocube and triangular nanoparticles were prepared by a seed-mediated growth process and the growth mechanism was studied by varying the volume of Pd precursors added to the Au seed solution. The atomic resolution STEM images revealed that the nanocube is formed from a single-crystal Au seed with rapid growth along directions while the triangular nanoparticles were obtained with growth preferentially along directions rather than direction. The strain generated by the lattice mismatch between fcc-Au and fcc-Pd, is released by Shockley partial dislocations (SPD), combined with stacking faults (SF) that appear at the final (outer) Pd layer. Then, as the shell grows the SPDs and SFs appear at the interface and combine with misfit dislocations, which finally diffuse to the free surfaces due to the alloying of Au into the Pd shell. In related work, magneto-plasmonic gold-cobalt (Au-Co) nanoparticles of diameter 4-nm were generated by a phase-transfer process and investigated by STEM, where the Z-contrast imaging and energy dispersive x-ray spectroscopy (EDS) showed inhomogeneous alloying between Au and Co at the nanoscale. The observed ferromagnetic behavior carries significance in biomedical applications. In addition, selected metallic (Au144(SR)60) and bimetallic (CuAu144) nanoclusters were obtained with thiolate-ligand protection and characterized using optical, MS, and STEM techniques. The optical spectrum and MS results established the monodispersity and purity of the nanoclusters. Another important aspect is that the emergence of broad strong plasmonic band centered near 520 nm (2.3-eV), by

  13. Atmospheric lifetimes and ozone depletion potentials of methyl bromide (CH3Br) and dibromomethane (CH2Br2)

    Energy Technology Data Exchange (ETDEWEB)

    Mellouki, A.; Talukdar, R.K.; Schmoltner, A.; Gierczak, T.; Mills, M.J.; Solomon, S.; Ravishankara, A.R. (NOAA, Boulder, CO (United States))

    1992-10-01

    The rate coefficients for the reactions of OH radical with CH3Br and CH2Br2 were measured as functions of temperature using the laser photolysis - laser induced fluorescence method. This data was incorporated into a semiempirical model (Solomon et al., 1992) and a 2D model to calculate the steady-state ozone depletion potentials (ODP) and atmospheri lifetimes, tau, with greatly improved accuracy as compared to earlier studies. The calculated ODPs and tau are 0.65 and 1.7 years and 0.17 and 0.41 years for CH3Br and CH2Br2, respectively, using the semiempirical model. These lifetimes agree well with those calculated using a 2D model. This study better quantifies the ODPs and tau of these species which are needed inputs for discussion of possible regulation of human emissions currently under international considerations. 29 refs.

  14. n vivo retention of ingested Au NPs by Daphnia magna: No evidence for trans-epithelial alimentary uptake

    Science.gov (United States)

    Khan, Farhan R.; Kennaway, Gabrielle M.; Croteau, Marie-Noële; Dybowska, Agnieszka; Smith, Brian D.; Nogueira, António J.A.; Rainbow, Philip S.; Luoma, Samuel N.; Valsami-Jones, Eugenia

    2014-01-01

    In vivo studies with Daphnia magna remain inconclusive as to whether engineered nanoparticles (NPs) are internalized into tissues after ingestion. Here we used a three-pronged approach to study the in vivo retention and efflux kinetics of 20 nm citrate stabilized Au NPs ingested by this key aquatic species. Daphnids were exposed to suspended particles (600 μg L−1) for 5 h after which they were depurated for 24 h in clean water containing algae. Light microscopy was used to follow the passage of Au NPs through the gastrointestinal tract, Au body burdens were determined by ICP-MS (inductively coupled plasma mass spectrometry), and transmission electron microscopy (TEM) was used to examine the presence and distribution of Au NPs in tissues. Results revealed that the elimination of Au NPs was bi-phasic. The fast elimination phase lasted −1 (±SE) which accounted for ∼75% of the ingested Au. The remaining ∼25% of the ingested Au NPs was eliminated at a 100-fold slower rate. TEM analysis revealed that Au NPs in the midgut were in close proximity to the peritrophic membrane after 1 and 24 h of depuration. There were no observations of Au NP uptake at the microvilli. Thus, although Au NPs were retained in the gut lumen, there was no observable internalization into the gut epithelial cells. Similar to carbon nanotubes and CuO NPs, our findings indicate that in daphnids the in vivo retention of Au NPs does not necessarily result in their internalization.

  15. Física cuántica y objetividad

    Directory of Open Access Journals (Sweden)

    Ferrero Melgar, Miguel

    2000-12-01

    Full Text Available Not available<br>>El mito Einstein se ha formado básicamente en torno a sus teorías relativistas que, entre otras implicaciones, conducían a una original concepción del espacio-tiempo e incluso a una nueva forma de descripción del mundo físico. No obstante, sus contribuciones a la teoría cuántica -aunque no tan divulgadas- son de tal envergadura que por sí solas constituyen un aporte más que suficiente para que su autor ocupara un destacadísimo lugar entre los grandes creadores científicos de todos los tiempos. En el presente trabajo nos proponemos justificar tan categórica afirmación, empleando los medios que la historiografía moderna ofrece e incluyendo también resultados de algunas investigaciones propias.

  16. Global polarization measurement in Au+Au collisions

    Energy Technology Data Exchange (ETDEWEB)

    Abelev, B.I.; Adams, J.; Aggarwal, M.M.; Ahammed, Z.; Amonett,J.; Anderson, B.D.; Anderson, M.; Arkhipkin, D.; Averichev, G.S.; Bai,Y.; Balewski, J.; Barannikova, O.; Barnby, L.S.; Baudot, J.; Bekele, S.; Belaga, V.V.; Bellingeri-Laurikainen, A.; Bellwied, R.; Benedosso, F.; Bhardwaj, S.; Bhasin, A.; Bhati, A.K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L.C.; Blyth, S.-L.; Bonner, B.E.; Botje, M.; Bouchet, J.; Brandin, A.V.; Bravar, A.; Bystersky, M.; Cadman, R.V.; Cai,X.Z.; Caines, H.; Calderon de la Barca Sanchez, M.; Castillo, J.; Catu,O.; Cebra, D.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen,H.F.; Chen, J.H.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Coffin, J.P.; Cormier, T.M.; Cosentino, M.R.; Cramer, J.G.; Crawford,H.J.; Das, D.; Das, S.; Daugherity, M.; de Moura, M.M.; Dedovich, T.G.; DePhillips, M.; Derevschikov, A.A.; Didenko, L.; Dietel, T.; Djawotho,P.; Dogra, S.M.; Dong, W.J.; Dong, X.; Draper, J.E.; Du, F.; Dunin, V.B.; Dunlop, J.C.; Dutta Mazumdar, M.R.; Eckardt, V.; Edwards, W.R.; Efimov,L.G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Filimonov, K.; Filip, P.; Finch,E.; Fine, V.; Fisyak, Y.; Fu, J.; Gagliardi, C.A.; Gaillard, L.; Ganti,M.S.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J.S.; Gorbunov, Y.G.; Gos,H.; Grebenyuk, O.; Grosnick, D.; Guertin, S.M.; Guimaraes, K.S.F.F.; Guo,Y.; Gupta, N.; Gutierrez, T.D.; Haag, B.; Hallman, T.J.; Hamed, A.; Harris, J.W.; He, W.; Heinz, M.; Henry, T.W.; Hepplemann, S.; Hippolyte,B.; Hirsch, A.; Hjort, E.; Hoffman, A.M.; Hoffmann, G.W.; Horner, M.J.; Huang, H.Z.; Huang, S.L.; Hughes, E.W.; Humanic, T.J.; Igo, G.; Jacobs,P.; Jacobs, W.W.; Jakl, P.; Jia, F.; Jiang, H.; Jones, P.G.; Judd, E.G.; Kabana, S.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Khodyrev,V.Yu.; Kim, B.C.; Kiryluk, J.; Kisiel, A.; Kislov, E.M.; Klein,S.R.; Kocoloski, A.; Koetke, D.D.; et al.

    2007-08-02

    The system created in non-central relativisticnucleus-nucleus collisions possesses large orbital angular momentum. Dueto spin-orbit coupling, particles produced in such a system could becomeglobally polarized along the direction of the system angular momentum. Wepresent the results of Lambda and anti-Lambda hyperon global polarizationmeasurements in Au+Au collisions at sqrt sNN=62.4 GeV and 200 GeVperformed with the STAR detector at RHIC. The observed globalpolarization of Lambda and anti-Lambda hyperons in the STAR acceptance isconsistent with zero within the precision of the measurements. Theobtained upper limit, lbar P Lambda, anti-Lambda rbar<= 0.02, iscompared to the theoretical values discussed recently in theliterature.

  17. Synthèse et caractérisation du quaternaire Cu 2 ZnSnS 4 (CZTS ...

    African Journals Online (AJOL)

    Le spectre Raman a indiqué la présence d'un pic kesterite principal à la position 336 cm-1 et l'existence d'un pic étrange à la position 424 cm-1 pouvant correspondre au composé binaire Cu2S. Les couches minces de CZTS ont montrés une transmission d'environ 39% et une absorption optique au dessus de 104 cm-1 ...

  18. Microwave surface resistance of bulk YBa/sub 2/Cu/sub 3/O/sub 6+//sub x/ material

    Energy Technology Data Exchange (ETDEWEB)

    Fathy, A.; Kalokitis, D.; Belohoubek, E.; Sundar, H.G.K.; Safari, A.

    1988-10-01

    Superconducting Y-Ba-Cu-O samples were prepared by conventional solid-state reaction. The microwave surface resistance of 1:2:3 compound superconductor material was measured in a special disk resonator structure at 10 GHz. At liquid-nitrogen temperatures the microwave surface resistance is comparable to that of Au. At lower temperature (approx.10 K) the surface resistance is an order of magnitude lower than that of Au at the same temperature.

  19. A inclusão das TICs na educação brasileira: problemas e desafios (La inclusión de las tecnologías de la información y la comunicación, TIC, en la educación brasileña: problemas y desafíos (The Inclusion of ICTs in Brazilian Education: Issues and Challenges (L′incorporation des TICs (technologies de l′information et la communication dans l′éducation au Brésil: problèmes et défisA inclusão das TICs na educação brasileira: problemas e desafios

    Directory of Open Access Journals (Sweden)

    Werlayne Stuart Soares-Leite

    2012-12-01

    ère critique-réflexif dans laquelle on aborde les principaux problèmes qui sont en rapport à l’usage des Technologies de l’Information et la Communication (TICs dans l’éducation au Brésil et aussi on con- seille un profil possible de l’enseignant qui veut utiliser ces outils dans sa pratique d’enseignement. L’insertion des TICs dans l’éducation peut-être un outil important pour améliorer le processus d’enseignement–appren- tissage. Néanmoins, ce qu’on voit actuellement dans l’éducation au Bré- sil c’est que la plupart d’enseignants n’utilisent pas ces technologies dans son travail d’enseignement.

  20. Finding the Missing Stratospheric Br(sub y): A Global Modeling Study of CHBr3 and CH2Br2

    Science.gov (United States)

    Liang, Q.; Stolarski, R. S.; Kawa, S. R.; Nielsen, J. E.; Douglass, A. R.; Rodriguez, J. M.; Blake, D. R.; Atlas, E. L.; Ott, L. E.

    2010-01-01

    Recent in situ and satellite measurements suggest a contribution of 5 pptv to stratospheric inorganic bromine from short-lived bromocarbons. We conduct a modeling study of the two most important short-lived bromocarbons, bromoform (CHBr3) and dibromomethane (CH2Br2), with the Goddard Earth Observing System Chemistry Climate Model (GEOS CCM) to account for this missing stratospheric bromine. We derive a "top-down" emission estimate of CHBr3 and CH2Br2 using airborne measurements in the Pacific and North American troposphere and lower stratosphere obtained during previous NASA aircraft campaigns. Our emission estimate suggests that to reproduce the observed concentrations in the free troposphere, a global oceanic emission of 425 Gg Br yr(exp -1) for CHBr3 and 57 Gg Br yr(exp -l) for CH2Br2 is needed, with 60% of emissions from open ocean and 40% from coastal regions. Although our simple emission scheme assumes no seasonal variations, the model reproduces the observed seasonal variations of the short-lived bromocarbons with high concentrations in winter and low concentrations in summer. This indicates that the seasonality of short-lived bromocarbons is largely due to seasonality in their chemical loss and transport. The inclusion of CHBr3 and CH2Br2 contributes 5 pptv bromine throughout the stratosphere. Both the source gases and inorganic bromine produced from source gas degradation (BrSLS) in the troposphere are transported into the stratosphere, and are equally important. Inorganic bromine accounts for half (2.5 pptv) of the bromine from the inclusion of CHBr3 and CHzBr2 near the tropical tropopause and its contribution rapidly increases to 100% as altitude increases. More than 85% of the wet scavenging of Br(sub y)(sup VSLS) occurs in large-scale precipitation below 500 hPa. Our sensitivity study with wet scavenging in convective updrafts switched off suggests that Br(sub y)(sup SLS) in the stratosphere is not sensitive to convection. Convective scavenging only

  1. d + Au hadron correlation measurements at PHENIX

    Energy Technology Data Exchange (ETDEWEB)

    Sickles, Anne M., E-mail: anne@bnl.gov

    2014-06-15

    In these proceedings, we discuss recent results from d + Au collisions in PHENIX ridge related measurements and their possible hydrodynamic origin. We present the v{sub 2} at midrapidity and measurements of the pseudorapidity dependence of the ridge, distinguishing between the d-going and Au-going directions. We investigate the possible geometrical origin by comparing v{sub 2} in d + Au to that in p + Pb, Au + Au and Pb + Pb collisions. Future plans to clarify the role of geometry in small collision systems at RHIC are discussed.

  2. Laser ablation of Au–CuO core–shell nanocomposite in water for optoelectronic devices

    Science.gov (United States)

    Ismail, Raid A.; Abdul-Hamed, Ryam S.

    2017-12-01

    Core–shell gold–copper oxide Au–CuO nanocomposites were synthesized using laser ablation of CuO target in colloidal solution of Au nanoparticles (NPs). The effect of laser fluence on the structural, morphological, electrical, and optical properties of Au–CuO nanocomposites was investigated using x-ray diffraction (XRD), atomic force microscope (AFM), scanning electron microscope (SEM), transmission electron microscope (TEM), photoluminescence (PL), Fourier transformed infrared spectroscopy (FTIR), Hall measurement, and UV–vis spectroscopy. X-ray diffraction results confirm the formation of polycrystalline Au–CuO NPs with monoclinic structure. The optical energy gap for CuO was 4 eV and for the Au–CuO core–shell nanocomposites was found to be in the range of 3.4–3.7 eV. SEM and TEM investigations revealed that the structure and morphology of Au–CuO core–shell nanocomposites were strongly depending on the laser fluence. A formation of Au–CuO nanospheres and platelets structures was observed. The photoluminescence data showed an emission of broad visible peaks between 407 and 420 nm. The effect of laser fluence on the dark and illuminated I–V characteristics of Au–CuO/n-Si heterojunction photodetectors was investigated and analyzed. The experimental data demonstrated that the photodetector prepared at optimum laser fluence exhibited photosensitivity of 0.6 AW‑1 at 800 nm.

  3. Decay spectroscopy of $^{178}$Au

    CERN Document Server

    Whitmore, B

    In this thesis, the neutron-deficient nucleus $^{178}$Au is investigated through decay spectroscopy. Si and HPGe detectors were used to analyse the decay radiation of $^{178}$Au and its daughter nuclei. Previous studies have been unable to distinguish decay radiation from different isomeric states of this nucleus. This thesis represents the first time such isomeric discrimination has been achieved, and presents tentative spin assignments of both the ground state and an isomer. The neutron-deficient gold isotopes are an area of interest for the study of shape coexistence. This is the phenomenon exhibited by nuclei able to exist at a number of close lying energy minima, each reflecting a distinct type of deformation. It is hoped that studies such as this can help identify the evolution of nuclear deformation in this region of the nuclear chart.

  4. Electrochemical detection of copper ions leached from CuO nanoparticles in saline buffers and biological media using a gold wire working electrode

    Science.gov (United States)

    Baldisserri, Carlo; Costa, Anna Luisa

    2016-04-01

    We performed explorative cyclic voltammetry in phosphate-buffered saline buffers, Dulbecco's modified Eagle's medium (DMEM), and fetal bovine serum-added DMEM using Au wire as working electrode, both in the absence and in the presence of known nominal concentrations of Cu2+ ions or 15 nm CuO nanoparticles. Addition of either Cu2+ ions or aqueous suspension of CuO nanoparticles caused a single anodic peak to appear in the double-layer region of all three pristine media. The height of the anodic peak was found to increase in a monotonic fashion vs. Cu2+ concentration in Cu2+-added media, and versus time since CuO addition in CuO-added media. Stepwise addition of glycine to Cu2+-added phosphate-buffered saline buffer caused an increasing cathodic shift of the anodic peak accompanied by decreasing peak currents. Results indicate that preparing Cu2+-free suspensions of CuO nanoparticles in such media is difficult, owing to the presence of leached copper ions. The implications on results of experiments in which CuO nanoparticle-added biological media are used as cell culture substrates are discussed. Literature data on the interactions between Cu2+ ions, dissolved carbon dioxide in aqueous CuO suspensions, and amino acids present in such media are compared to our results.

  5. Le CRDI au Costa Rica

    International Development Research Centre (IDRC) Digital Library (Canada)

    La stabilité politique du Costa Rica a fait de ce pays un partenaire essen- tiel du CRDI en Amérique centrale pour la recherche portant sur l'agriculture, les politiques économiques, la démocratisation et la prévention des catastrophes naturelles. Le CRDI a beaucoup contribué à la recherche en agriculture au Costa Rica,.

  6. Cas de Cotonou au Benin

    African Journals Online (AJOL)

    Au nombre de ces nuisances, figurent entre autres, la perte de temps et par ricochet d'importantes recettes .... La méthodologie utilisée est basée sur deux types d'approches : l'approche théorique et celle empirique. Le premier volet de ...... Université de Bordeaux Talence, 456 pages. SEGBEDJI, E. (2001) : Impact du trafic ...

  7. Group ib organometallic chemistry. XXXIV. Thermal behaviour and chemical reactivity of tetranuclear Me2N-substituted diarypropenylcopper-copper anion (Vi2Cu4X2) and mixed diarylpropenyl/organocopper (Vi2Cu4R2) compounds

    NARCIS (Netherlands)

    Hoedt, R.W.M. ten; Koten, G. van; Noltes, J.G.

    1980-01-01

    Thermal decomposition of configurationally pure 1,2-diarylpropenylcopper compounds Z-Vi2CU4Br2 and Z-Vi2Cu4R2 [Vi = (2-Me2NC6H4)C=C(Me)-(C6H4Me-4), R = 2-Me2NC6H4 or 4-MeC6H4CC] predominantly results in the formation of ViH. In contrast, only dimers (ViVi) were formed on thermolysis of (Z-ViCu2OTf)η

  8. Molecular characterization of BrMYB28 and BrMYB29 paralogous transcription factors involved in the regulation of aliphatic glucosinolate profiles in Brassica rapa ssp. pekinensis.

    Science.gov (United States)

    Baskar, Venkidasamy; Park, Se Won

    2015-07-01

    Glucosinolates (GSL) are one of the major secondary metabolites of the Brassicaceae family. In the present study, we aim at characterizing the multiple paralogs of aliphatic GSL regulators, such as BrMYB28 and BrMYB29 genes in Brassica rapa ssp. pekinensis, by quantitative real-time PCR (qRT-PCR) analysis in different tissues and at various developmental stages. An overlapping gene expression pattern between the BrMYBs as well as their downstream genes (DSGs) was found at different developmental stages. Among the BrMYB28 and BrMYB29 paralogous genes, the BrMYB28.3 and BrMYB29.1 genes were dominantly expressed in most of the developmental stages, compared to the other paralogs of the BrMYB genes. Furthermore, the differential expression pattern of the BrMYBs was observed under various stress treatments. Interestingly, BrMYB28.2 showed the least expression in most developmental stages, while its expression was remarkably high in different stress conditions. More specifically, the BrMYB28.2, BrMYB28.3, and BrMYB29.1 genes were highly responsive to various abiotic and biotic stresses, further indicating their possible role in stress tolerance. Moreover, the in silico cis motif analysis in the upstream regulatory regions of BrMYBs showed the presence of various putative stress-specific motifs, which further indicated their responsiveness to biotic and abiotic stresses. These observations suggest that the dominantly expressed BrMYBs, both in different developmental stages and under various stress treatments (BrMYB28.3 and BrMYB29.1), may be potential candidate genes for altering the GSL level through genetic modification studies in B. rapa ssp. pekinensis. Copyright © 2015. Published by Elsevier SAS.

  9. L’apprentissage au CERN

    CERN Multimedia

    Staff Association

    2016-01-01

    En 1961, sur la base du constat que l’évolution du marché du travail nécessitait un besoin croissant de personnel qualifié, le 1er accord entre la République et canton de Genève et le CERN fut signé. Cet accord avait notamment pour objet la formation professionnelle de jeunes électroniciens et techniciens de laboratoires en physique. Le CERN, acteur local économique d’importance, soulignait par cet accord sa volonté de participer au développement économique et social local. Le 1er apprenti arriva au CERN en 1965. En 1971, le centre d’apprentissage fut créé ; il accueille aujourd’hui plus d’une vingtaine d’apprentis au total, à raison d’environ six nouveaux apprentis chaque année. Cet apprentissage est dédié aux jeunes âgés e...

  10. Fabricating a Homogeneously Alloyed AuAg Shell on Au Nanorods to Achieve Strong, Stable, and Tunable Surface Plasmon Resonances

    KAUST Repository

    Huang, Jianfeng

    2015-08-13

    Colloidal metal nanocrystals with strong, stable, and tunable localized surface plasmon resonances (SPRs) can be useful in a corrosive environment for many applications including field-enhanced spectroscopies, plasmon-mediated catalysis, etc. Here, a new synthetic strategy is reported that enables the epitaxial growth of a homogeneously alloyed AuAg shell on Au nanorod seeds, circumventing the phase segregation of Au and Ag encountered in conventional synthesis. The resulting core–shell structured bimetallic nanorods (AuNR@AuAg) have well-mixed Au and Ag atoms in their shell without discernible domains. This degree of mixing allows AuNR@AuAg to combine the high stability of Au with the superior plasmonic activity of Ag, thus outperforming seemingly similar nanostructures with monometallic shells (e.g., Ag-coated Au NRs (AuNR@Ag) and Au-coated Au NRs (AuNR@Au)). AuNR@AuAg is comparable to AuNR@Ag in plasmonic activity, but that it is markedly more stable toward oxidative treatment. Specifically, AuNR@AuAg and AuNR@Ag exhibit similarly strong signals in surface-enhanced Raman spectroscopy that are some 30-fold higher than that of AuNR@Au. When incubated with a H2O2 solution (0.5 m), the plasmonic activity of AuNR@Ag immediately and severely decayed, whereas AuNR@AuAg retained its activity intact. Moreover, the longitudinal SPR frequency of AuNR@AuAg can be tuned throughout the red wavelengths (≈620–690 nm) by controlling the thickness of the AuAg alloy shell. The synthetic strategy is versatile to fabricate AuAg alloyed shells on different shaped Au, with prospects for new possibilities in the synthesis and application of plasmonic nanocrystals.

  11. Phase Control of BR/SBR Blends by Silica Particles

    Science.gov (United States)

    Inai, Motoyuki; Aizawa, Seiji; Ito, Masayoshi

    A phase control of butadiene rubber (BR)/styrene-butadiene rubber (SBR) blends was examined by using silica particles. The phase structure of the blends was qualitatively evaluated from transmission electron microscope (TEM) observation and temperature dependence of mechanical tanδ. It was found that the temperature dependence of tanδ was dependent on the size of agglomerate formed by silica particles in the blend. The vulcanized blends with small agglomerates showed a single tanδ peak suggesting a pseudo-miscible state. The vulcanized blends with large agglomerates showed two tanδ peaks corresponding to the Tgs of BR and SBR. The mutual dissolution of BR and SBR phases above the UCST line where the vulcanization was carried out might be disturbed by large agglomerates formed by silica particles in the blends.

  12. Synthesis and structural chemistry of Au(III)-substituted Ba2YCu3O(7-delta)

    Science.gov (United States)

    Hepp, A. F.; Gaier, J. R.; Pouch, J. J.; Banerjea, A.; Hambourger, P. D.

    1988-01-01

    Gold-substituted superconductors, Ba2Y(Au(x)Cu(1-x))3O(7-delta) (x = 0-0.1) were synthesized. For x = 0.1, there was no change in the a and b lattice parameters (a = 3.826 A and b = 3.889 A) but a 0.06 A c axis expansion to 11.75 A was observed. Substituted gold is found to be trivalent by XPS. Replacing Cu(1) in the copper oxide chain with a slight reordering of oxygen is consistent with c axis expansion. The formal charge of the site remains trivalent; remaining Cu in the chains may be reduced resulting in an oxygen stoichiometry is less than or equal to 7. A small effect on T(sub c)(89 K for x = 0.10) is observed upon gold substitution.

  13. LA RÉCENTE DINAMIQUE GEOECONOMIQUE DE LA CHAINE DE PRODUCTION DE SOJA AU BRÉSIL ET DANS LE MONDE

    Directory of Open Access Journals (Sweden)

    Roberto César Cunha

    2015-07-01

    Full Text Available L’agro-industrie de soja consolidé, au Brésil, à partir des années 1980, se constitue comme une des principales chaînes productives de la structure agricole brésilienne, offrant des grains, son de blé e d’huiles pour l’approvisionnement du marché interne et externe. Dans la récolte 2013/2014, la production a atteint plus de 87 millions de tonnes cultivées en trente millions hectares, qui représentent juste 8,9% dans la domaine cultivées au Bresil. Les exportations de soja em grains couvrent 42 millions de tonnes dans l’année agricole 2012/2013, l’équivalent a U$ 22,8 milliards. Les segments de grains, huile e son de blé ont gagné U$ S 31 milliards, qui signifie 12,8 % de toutes les ventes externes du Brésil et 31 % des exportations de l’agro-industrie brésiliens. Ce texte a pour objectif d’identifier les facteurs responsables de la recente dinamique de cette chaîne productive dans le territoire bresilien et son insertion au marché mondial.

  14. Balloon-borne stratospheric BrO measurements: comparison with Envisat/SCIAMACHY BrO limb profiles

    Directory of Open Access Journals (Sweden)

    M. Dorf

    2006-01-01

    Full Text Available For the first time, results of four stratospheric BrO profiling instruments, are presented and compared with reference to the SLIMCAT 3-dimensional chemical transport model (3-D CTM. Model calculations are used to infer a BrO profile validation set, measured by 3 different balloon sensors, for the new Envisat/SCIAMACHY (ENVIronment SATellite/SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY satellite instrument. The balloon observations include (a balloon-borne in situ resonance fluorescence detection of BrO (Triple, (b balloon-borne solar occultation DOAS measurements (Differential Optical Absorption Spectroscopy of BrO in the UV, and (c BrO profiling from the solar occultation SAOZ (Systeme d'Analyse par Observation Zenithale balloon instrument. Since stratospheric BrO is subject to considerable diurnal variation and none of the measurements are performed close enough in time and space for a direct comparison, all balloon observations are considered with reference to outputs from the 3-D CTM. The referencing is performed by forward and backward air mass trajectory calculations to match the balloon with the satellite observations. The diurnal variation of BrO is considered by 1-D photochemical model calculation along the trajectories. The 1-D photochemical model is initialised with output data of the 3-D model with additional constraints on the vertical transport, the total amount and photochemistry of stratospheric bromine as given by the various balloon observations. Total [Bry]=(20.1±2.5 pptv obtained from DOAS BrO observations at mid-latitudes in 2003, serves as an upper limit of the comparison. Most of the balloon observations agree with the photochemical model predictions within their given error estimates. First retrieval exercises of BrO limb profiling from the SCIAMACHY satellite instrument on average agree to around 20% with the photochemically-corrected balloon observations of the remote sensing instruments (SAOZ

  15. Les séquelles de brûlures en chirurgie pédiatrique au CHU Gabriel ...

    African Journals Online (AJOL)

    In Mali, the care of burned children is ensured in the pediatric surgery department that has no specialist in plastic surgery and burns among its staff. In a study in the service, 47.1% of burns healed with scars [1]. The aim of this work was to describe treatment strategies in our context. It was a retrospective study of 5 years ...

  16. Entrée des jeunes dans l'arène politique au Brésil | CRDI - Centre ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    18 oct. 2010 ... Secundo, la mobilisation est bien réelle : la conférence nationale sur la jeunesse a donné lieu à l'établissement d'un conseil national de la jeunesse grâce auquel des jeunes, des politiciens et des fonctionnaires s'asseoient à la même table. Ces réalisations et d'autres sont relatées dans l'ouvrage intitulé ...

  17. De la Démocratie au Brésil: Tocqueville de novo em missão

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Almeida

    2009-12-01

    Full Text Available O francês Alexis de Tocqueville vem ao Brasil, a serviço do Banco Mundial, para examinar a situação do país do ponto de vista do funcionamento das instituições democráticas e da economia de mercado. Tendo chegado bem intencionado, ele constata irregularidades e aspectos disfuncionais em praticamente todas as instituições que visitou e nos mecanismos políticos e econômicos que examinou. Constata a deterioração da democracia e os avanços do estatismo, aliás apreciado e valorizado no Brasil. Parte de volta a Washington frustrado.

  18. Méga-événements en Inde, au Brésil et en Afrique du Sud: Des ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    13 déc. 2016 ... Dans cet article de 2015, Brij Maharaj de l'Université de Kwazulu-Natal présente une perspective manquante, en examinant trois méga-événements récents dans le Sud Global: les Jeux du Commonwealth 2010 à Delhi, en Inde; La Coupe du Monde de la FIFA 2010 en Afrique du Sud; Et la C