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Sample records for au melange co2-ch4

  1. Reprint of: CO2/CH4, CH4/H-2 and CO2/CH4/H-2 separations at high pressures using Mg-2(dobdc)

    NARCIS (Netherlands)

    Z.R. Herm; R. Krishna; J.R. Long

    2012-01-01

    High-pressure separations of binary and ternary mixtures of CO2, CH4, and H2 are relevant to carbon dioxide capture as well as hydrogen and natural gas purification. Metal-organic frameworks represent a class of porous materials that could be used to accomplish these separations, and Mg2(dobdc) (dob

  2. CO2/CH4, CH4/H-2 and CO2/CH4/H-2 separations at high pressures using Mg-2(dobdc)

    NARCIS (Netherlands)

    Z.R. Herm; R. Krishna; J.R. Long

    2012-01-01

    High-pressure separations of binary and ternary mixtures of CO2, CH4, and H2 are relevant to carbon dioxide capture as well as hydrogen and natural gas purification. Metal-organic frameworks represent a class of porous materials that could be used to accomplish these separations, and Mg2(dobdc) (dob

  3. The incorporation of graphene oxide into polysulfone mixed matrix membrane for CO2/CH4 separation

    Science.gov (United States)

    Zahri, K.; Goh, P. S.; Ismail, A. F.

    2016-06-01

    Carbon dioxide (CO2) is often found as the main impurity in natural gas, where methane (CH4) is the major component. The presence of CO2 in natural gas leads to several problems such as reducing the energy content of natural gas and cause pipeline corrosion. Thus it must be removed to meet specifications (CO2 ≤ 2 mol%) before the gas can be delivered to the pipeline. In this work, hollow fiber mixed matrix membrane (MMM) were fabricated by embedding graphene oxide (GO) into a polysulfone (PSf) polymer matrix to improve membrane properties as well as its separation performance towards CO2/CH4 gas. The membrane properties were investigated for pristine membrane and mixed matrix membrane filled with filler loading of 0.25%. The synthesized GO and properties of fabricated membranes were characterized and studied using TEM, AFM, XRD, FTIR and SEM respectively. The permeance of pure gases and ideal selectivity of CO2/CH4 gas were determined using pure gas permeation experiment. GO has affinity towards CO2 gas. The nanosheet structure creates path for small molecule gas and restricted large molecule gas to pass through the membrane. The incorporation of GO in PSf polymer enhanced the permeance of CO 2 and CO2/CH4 separation from 64.47 to 86.80 GPU and from 19 to 25 respectively.

  4. Flask sample measurements for CO2, CH4 and CO using cavity ring-down spectrometry

    Directory of Open Access Journals (Sweden)

    J.-L. Wang

    2013-08-01

    Full Text Available In recent years, cavity ring-down spectrometry (CRDS has been demonstrated to be a highly sensitive, stable and fast analytical technique for real-time in situ measurements of greenhouse gases. In this study, we propose the technique (which we call flask-CRDS of analyzing whole air flask samples for CO2, CH4 and CO using a custom gas manifold designed to connect to a CRDS analyzer. Extremely stable measurements of these gases can be achieved over a large pressure range in the flask, from 175 to 760 Torr. The wide pressure range is conducive to flask sample measurement in three ways: (1 flask samples can be collected in low-pressure environments (e.g. high-altitude locations; (2 flask samples can be first analyzed for other trace gases with the remaining low-pressure sample for CRDS analysis of CO2, CH4 and CO; and (3 flask samples can be archived and re-analyzed for validation. The repeatability of this method (1σ of 0.07 ppm for CO2, 0.4 ppb for CH4, and 0.5 ppb for CO was assessed by analyzing five canisters filled with the same air sample to a pressure of 200 Torr. An inter-comparison of the flask-CRDS data with in-situ CRDS measurements at a high-altitude mountain baseline station revealed excellent agreement, with differences of 0.10 ± 0.09 ppm (1σ for CO2 and 0.9 ± 1.0 ppb for CH4. This study demonstrated that the flask-CRDS method was not only simple to build and operate but could also perform highly accurate and precise measurements of atmospheric CO2, CH4 and CO in flask samples.

  5. PEBAX®/PAN Hollow Fiber Membranes for CO2/CH4 Separation

    Czech Academy of Sciences Publication Activity Database

    Esposito, E.; Clarizia, G.; Bernardo, P.; Jansen, J. C.; Sedláková, Zuzana; Izák, Pavel; Curcio, S.; de Cindio, B.; Tasselli, F.

    2015-01-01

    Roč. 94, SI (2015), s. 53-61. ISSN 0255-2701. [International Congress of Chemical and Process Engineering CHISA 2014 /21./ and Conference PRES 2014 /17./. Prague, 23.08.2014-27.08.2014] R&D Projects: GA ČR GA14-12695S Grant ostatní: INRP(IT) MicroPERLA:PON01_01840 Institutional support: RVO:67985858 Keywords : composite membrane * hollow fibers * CO2/CH4 separation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.071, year: 2014

  6. Deactivation and Coke Accumulation during CO2/CH4 Reforming over Pt Catalysts

    OpenAIRE

    Bitter, J.H.; Seshan, K.; Lercher, J.A.

    2001-01-01

    The Deactivation of Pt catalysts used in the generation of synthesis gas via CO2/CH4 reforming depends strongly on the support and the metalparticle size. Methods of Physicochemical characterization such as X-ray absorption spectroscopy and hydrogen chemisorption suggest that carbon formation (most likely from methane) rather than sintering is the main cause of catalyst deactivation. The rate of carbon formation decreased in the order Pt/y-Al2O3 >> Pt/TiO2 > Pt/ZrO2. Carbon was formed on the ...

  7. Synergetic effect of carbon nanopore size and surface oxidation on CO2 capture from CO2/CH4 mixtures

    OpenAIRE

    Furmaniak, Sylwester; KOWALCZYK, PIOTR; Terzyk, Artur P.; Gauden, Piotr A.; Harris , P. J. F.

    2013-01-01

    We have studied the synergetic effect of confinement (carbon nanopore size) and surface chemistry (the number of carbonyl groups) on CO2 capture from its mixtures with CH4 at typical operating conditions for industrial adsorptive separation (298 K and compressed CO2CH4 mixtures). Although both confinement and surface oxidation have an impact on the efficiency of CO2/CH4 adsorptive separation at thermodynamics equilibrium, we show that surface functionalization is the most important factor in ...

  8. Phase equilibria for the ionic semiclathrate hydrate formed with tetrabutylphosphonium chloride plus CO2, CH4, or N2

    International Nuclear Information System (INIS)

    Highlights: • Hydrate phase equilibria for CO2, CH4, or N2 + tetrabutylphosphonium chloride. • Range of the equilibrium temperature is from (283.0 to 291.8) K. • The mass fraction of tetrabutylphosphonium chloride aqueous solution is 0.36. • Tetrabutylphosphonium chloride moderated phase equilibrium of CO2, CH4 or N2 hydrate at least 8 K. • The gas separation performance in tetrabutylphosphonium chloride hydrate systems. -- Abstract: This paper presents the phase equilibrium conditions for the semiclathrate hydrates in the systems of (CO2, CH4 or N2 + tetrabutylphosphonium chloride + water). The experiments were performed by isochoric method within the range of temperature from (283.0 to 291.8) K and pressure from (0.19 to 5.02) MPa with mass fraction of tetrabutylphosphonium chloride aqueous solution 0.36. The presence of tetrabutylphosphonium chloride increases the phase equilibrium temperatures of CO2, CH4 or N2 hydrates by at least 8 K at a given pressure. The gas separation performance in tetrabutylphosphonium chloride hydrate systems was compared with that in other semiclathrate hydrate systems, based on the measured phase equilibrium conditions

  9. 金属有机骨架材料在CO2/CH4吸附分离中的研究进展%Progress of adsorption-based CO2/CH4 separation by metal organic frameworks

    Institute of Scientific and Technical Information of China (English)

    张所瀛; 刘红; 刘朋飞; 吴培培; 杨祝红; 阳庆元; 陆小华

    2014-01-01

    CO2/CH4分离能耗高是生物甲烷过程核心难题之一。金属有机骨架材料(metal organic frameworks,MOFs)由于其优异的CO2吸附分离性能,被视为最具潜力的CO2分离捕集材料,近年来引起了广泛的关注。本文结合沼气的特点和MOFs研究的最新进展,对MOFs材料在CO2/CH4吸附分离过程的相关实验研究工作进行了综述。%The high energy penalty of CO2 separation from biogas is a core problem in the biomethane process. Metal organic frameworks (MOFs) have recently attracted intense research interest because of their ultra-high CO2 adsorption capacity and potential applications as novel adsorbents to reduce energy cost. The recent progress of experimental researches on adsorption-based CO2/CH4 separation by MOFs is reviewed.

  10. Screening metal-organic framework-based mixed-matrix membranes for CO2/CH4 separations

    OpenAIRE

    Keskin, Seda; Eruçar, İlknur

    2011-01-01

    1 Screening Metal Organic Framework-based Mixed Matrix Membranes for CO2/CH4 Separations Ilknur Erucar† and Seda Keskin‡* †Department of Computational Sciences and Engineering, Koç University, 34450, Istanbul, Turkey ‡Department of Chemical and Biological Engineering, Koç University, 34450, Istanbul, Turkey Submitted to Ind. Eng. Chem. Res. Abstract In this study, the challenge of selecting metal organic frameworks (MOFs) as filler particles in high performance mixe...

  11. Winter greenhouse gas fluxes (CO2, CH4 and N2O from a subalpine grassland

    Directory of Open Access Journals (Sweden)

    L. Merbold

    2013-05-01

    Full Text Available Although greenhouse gas emissions during winter contribute significantly to annual balances, their quantification is still highly uncertain in snow-covered ecosystems. Here, carbon dioxide (CO2, methane (CH4 and nitrous oxide (N2O fluxes were measured at a subalpine managed grassland in Switzerland using concentration gradients within the snowpack (CO2, CH4, N2O and the eddy covariance method (CO2 during the winter 2010/2011. Our objectives were (1 to identify the temporal and spatial variation of greenhouse gases (GHGs and their drivers, and (2 to estimate the GHG budget of the site during this specific season (1 December–31 March, 121 days. Mean winter fluxes (December–March based on the gradient method were 0.77 ± 0.54 μmol m−2 s−1 for CO2 (1.19 ± 1.05 μmol m−2 s−1 measured by eddy covariance, −0.14 ± 0.09 nmol m−2 s−1 for CH4 and 0.23 ± 0.23 nmol m−2 s−1 for N2O, respectively. In comparison with the CO2 fluxes measured by eddy covariance, the gradient technique underestimated the effluxes by 50%. While CO2 and CH4 fluxes decreased with the progressing winter season, N2O fluxes did not follow a seasonal pattern. The major variables correlating with the fluxes of CO2 and CH4 were soil temperature and snow water equivalent, which is based on snow height and snow density. N2O fluxes were only explained poorly by any of the measured environmental variables. Spatial variability across the valley floor was smallest for CO2 and largest for N2O. During the winter season 2010/2011, greenhouse gas fluxes ranged between 550 ± 540 g CO2 m−2 estimated by the eddy covariance approach and 543 ± 247 g CO2 m−2, −0.4 ± 0.01 g CH4 m−2 and 0.11 ± 0.1 g N2O m−2 derived by the gradient technique. Total seasonal greenhouse gas emissions from the grassland were between 574 ± 276 and 581 ± 569 g CO2 eq. m−2, with N2O contributing 5% to the overall budget and CH4 reducing the budget by 0.1%. Cumulative budgets of CO2 were

  12. Experimental measurements of vapor-liquid equilibria of the H2O + CO2 + CH4 ternary system

    Science.gov (United States)

    Qin, J.; Rosenbauer, R.J.; Duan, Zhenhao

    2008-01-01

    Reported are the experimental measurements on vapor-liquid equilibria in the H2O + CO2 + CH4 ternary system at temperatures from (324 to 375) K and pressures from (10 to 50) MPa. The results indicate that the CH4 solubility in the ternary mixture is about 10 % to 40 % more than that calculated by interpolation from the Henry's law constants of the binary system, H2O + CH4, and the solubility of CO2 is 6 % to 20 % more than what is calculated by the interpolation from the Henry's law constants of the binary mixture, H 2O + CO2. ?? 2008 American Chemical Society.

  13. Fluxes of the greenhouse gases (CO2, CH4 and N2O) above a short-rotation poplar plantation after conversion from agricultural land

    OpenAIRE

    Zona, D.; I. A. Janssens; M. Aubinet; Gioli, B.; Vicca, S.; Fichot, R.; Ceulemans, R.

    2013-01-01

    Abstract: The increasing demand for renewable energy may lead to the conversion of millions of hectares into bioenergy plantations with a possible substantial transitory carbon (C) loss. In this study we report on the greenhouse gas fluxes (CO2, CH4, and N2O) measured using eddy covariance of a short-rotation bioenergy poplar plantation converted from agricultural fields. During the first six months after the establishment of the plantation (JuneDecember 2010) there were substantial CO2, CH4,...

  14. Low temperature diamond growth using CO2/CH4 plasmas: Molecular beam mass spectrometry and computer simulation investigations

    Science.gov (United States)

    Petherbridge, James R.; May, Paul W.; Pearce, Sean R. J.; Rosser, Keith N.; Ashfold, Michael N. R.

    2001-01-01

    Microwave plasma enhanced chemical vapor deposition has been used to grow diamond films at substrate temperatures down to 435 °C using CO2/CH4 gas mixtures. An Arrhenius plot of growth rate as a function of substrate temperature yields a value for the activation energy for the growth step of 28 kJ mol-1. This is lower than that measured previously for CH4/H2 systems and hints at a different gas-surface chemistry when using CH4/CO2 plasmas. Molecular beam mass spectrometry has been used to measure simultaneously the concentrations of the dominant gas phase species present during growth, for a wide range of plasma gas mixtures (0%-80% CH4, balance CO2). The CHEMKIN computer package has also been used to simulate the experimental results in order to gain insight into the major reactions occurring within the microwave plasma. The calculated trends for all species agree well with the experimental observations. Using these data, the model for the gas phase chemistry can be reduced to only four overall reactions. Our findings suggest that CH3 radicals are likely to be the key growth species when using CO2/CH4 plasmas and provide a qualitative explanation for the narrow concentration window for diamond growth.

  15. Fluxes of CO2,CH4 and N2O from alpine grassland in the Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    PEIZhiyong; OUYANGHua; ZHOUCaiping; XUXingliang

    2003-01-01

    Using static chamber technique,fluxes of CO2,CH4 and N2O were measured in the alpine grassland area from July 2000 to July 2001,determinations of mean fluxes showed that CO2 and N2O were generally released from the soil,while the alpine grassland accounted for a weak CH4 sink.Fluxes of CO2,CH4 and N2O ranged widely.The highest CO2 emission occurred in August,whereas almost 90?of the whole year emission occurred in the growing season.But the variations of CH4 and N2O fluxes did not show any clear patterns over the one-year-experiment.During a daily variation,the maximum CO2 emission occurred at 16:00,and then decreased to the minimum emission in the early morning.Daily pattern analyses indicated that the variation in CO2 fluxes was positively related to air temperatures(R2=0.73)and soil temperatures at a depth of 5 cm(R2=0.86),whereas daily variations in CH4 and N2O fluxes were poorly explained by soil temperatures and climatic variables.CO2 emissions in this area were much lower than other grasslands in plain areas.

  16. Plasticization-resistant hollow fiber membranes for CO2/CH4 separation based on a thermally crosslinkable polyimide

    KAUST Repository

    Chen, Chien-Chiang

    2011-10-01

    Decarboxylation-induced thermal crosslinking has been demonstrated to be effective for stabilizing membranes against plasticization in dense films. This study extends this promising crosslinking approach from dense films to industrially relevant asymmetric hollow fiber membranes. Crosslinkable asymmetric hollow fiber membranes were spun from a carboxylic acid containing polyimide, 6FDA-DAM:DABA. Dope and spinning conditions were optimized to obtain fibers with a defect-free selective skin layer. It is found that slightly defective fibers suffered severe selectivity loss after thermal crosslinking, suggesting that defect-free property is essential to the performance of the resulting crosslinked hollow fiber membranes. The crosslinked fibers were tested for CO 2/CH 4 separation. The excellent plasticization resistance under high pressure feeds (with highest CO 2 partial pressure of 400psia) suggests that these robust membranes are promising for aggressive natural gas purification. © 2011 Elsevier B.V.

  17. Molecular simulations on diameter effect of carbon nanotube for separation of CO2/CH4%不同管径碳纳米管中CO2/CH4分离的分子模拟

    Institute of Scientific and Technical Information of China (English)

    曹伟; 吕玲红; 黄亮亮; 王珊珊; 朱育丹

    2014-01-01

    生物甲烷路线在CO2减排和节能方面有很大的应用前景。而对生物沼气的分离是此路线的一个关键问题,特别是在60℃和0.1 MPa下。巨正则Monte Carlo(GCMC)和平衡分子动力学(EMD)的分子模拟方法研究CO2和CH4在不同管径的碳纳米管(CNT)中的吸附和扩散,可以从分子层面研究生物沼气的分离机理。分别计算了CO2/CH4二元混合物吸附量、吸附选择性、自扩散系数和渗透选择性等参数。模拟结果表明:由于碳管的受限空间和CO2与碳纳米管壁面分子之间强相互作用,导致二元等物质的量的混合物CO2/CH4的吸附量和扩散系数的差异。CO2的吸附量和自扩散系数都比CH4的大。渗透选择性在碳管管径达到最接近1 nm时达到最大值,此时混合物的分离过程是吸附控制,而非扩散控制。%Biomethane route has large potential in emission reduction and energy saving. One of the key issues is separation of biogas in operating conditions of 333 K and 0.1 MPa. Grand canonical Monte Carlo (GCMC) and equilibrium molecular dynamics simulations (EMD) were used to compute adsorption loadings and self-diffusivities of CH4/CO2 at various diameters of carbon nanotube (CNT) bundles. Single component and equimolar gases were simulated. CO2 always had larger adsorption loading and diffusion coefficient than CH4 as the result of relatively strong interaction between CO2 molecules and tube walls, due to the confined capacity. The permselectivity reached a maximum in closely 1 nm, and under such conditions the separation process was controlled by adsorption rather than diffusion.

  18. Continuous CO2/CH4/CO measurements (2012-2014) at Beromünster tall tower station in Switzerland

    Science.gov (United States)

    Satar, Ece; Berhanu, Tesfaye A.; Brunner, Dominik; Henne, Stephan; Leuenberger, Markus

    2016-05-01

    The understanding of the continental carbon budget is essential to predict future climate change. In order to quantify CO2 and CH4 fluxes at the regional scale, a measurement system was installed at the former radio tower in Beromünster as part of the Swiss greenhouse gas monitoring network (CarboCount CH). We have been measuring the mixing ratios of CO2, CH4 and CO on this tower with sample inlets at 12.5, 44.6, 71.5, 131.6 and 212.5 m above ground level using a cavity ring down spectroscopy (CRDS) analyzer. The first 2-year (December 2012-December 2014) continuous atmospheric record was analyzed for seasonal and diurnal variations and inter-species correlations. In addition, storage fluxes were calculated from the hourly profiles along the tower. The atmospheric growth rates from 2013 to 2014 determined from this 2-year data set were 1.78 ppm yr-1, 9.66 ppb yr-1 and -1.27 ppb yr-1 for CO2, CH4 and CO, respectively. After detrending, clear seasonal cycles were detected for CO2 and CO, whereas CH4 showed a stable baseline suggesting a net balance between sources and sinks over the course of the year. CO and CO2 were strongly correlated (r2 > 0.75) in winter (DJF), but almost uncorrelated in summer. In winter, anthropogenic emissions dominate the biospheric CO2 fluxes and the variations in mixing ratios are large due to reduced vertical mixing. The diurnal variations of all species showed distinct cycles in spring and summer, with the lowest sampling level showing the most pronounced diurnal amplitudes. The storage flux estimates exhibited reasonable diurnal shapes for CO2, but underestimated the strength of the surface sinks during daytime. This seems plausible, keeping in mind that we were only able to calculate the storage fluxes along the profile of the tower but not the flux into or out of this profile, since no Eddy covariance flux measurements were taken at the top of the tower.

  19. Quantifying Urban-Ecosystem Atmosphere Fluxes of N2O, CO2, CH4 over Denver, Colorado.

    Science.gov (United States)

    Anderson, D. E.; Tindall, J.; Thienelt, T.

    2004-12-01

    Urban ecosystems are complex, rapidly expanding, and the location of strong emissions of greenhouse gases. Ecosystem-atmosphere exchanges of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and water vapor were measured over a ~30 km2 portion of Denver, Colorado. Equipment used in these measurements included eddy covariance sensors at two levels on a tall 120m tower for CO2 flux and evapotranspiration (ET), soil surface chambers for the measurement of CO2, CH4, and N2O fluxes at 33 locations, and direct flux measurements of CO2 and N2O from the water treatment system. Measurement of CO2 flux and ET has been continuous for more than two years (2002-2004). Chamber measurements were conducted on selected dates during two growing seasons. Direct flux measurements from the water treatment system were conducted on a monthly basis in the 2004 summer. Measurements indicate both strong temporal and spatial heterogeneity of fluxes owing to characteristics of natural and anthropogenic ecosystem components. Tower-based eddy covariance measurements indicated that the urban ecosystem was a net CO2 source when measurements were averaged over a day or longer. However, during the majority of mid-day summer hours it was a weak sink, sequestering atmospheric CO2. In this case, the weak sink may indicate that the vegetative sink for CO2 was stronger than anthropogenic emissions of CO2 from heavy traffic on nearby highways in the flux footprint. Chamber-based measurements of CH4 flux over most dry land surfaces with vegetation varied from -0.3 to 2.6mmol/m2/d while the range in N2O flux was ~0 to 0.2\\mu mol/m2/d. For both fluxes, the higher values were observed over wet soils (>20%, volumetric). In contrast, at certain locations over a landfill (closed more than 30years ago) and converted to other uses (light industry, city park and golf course), CO2, CH4 and N2O fluxes were a few orders of magnitude higher than that found anywhere else in the city. However, for the majority

  20. The Cost of Using Global Warming Potentials. Analysing the Trade off Between CO2, CH4 and N2O

    International Nuclear Information System (INIS)

    The metric governing the trade-off between different greenhouse gases in the Kyoto Protocol, the Global Warming Potentials (GWPs), has received ample critique from both scientific and economic points of view. Here we use an integrated climate-economic optimization model to estimate the cost-effective trade-off between CO2, CH4 and N2O when meeting a temperature stabilization target. We then estimate the increased cost from using GWPs when meeting the same temperature target. Although the efficient valuation of the gases differs significantly from their respective GWPs, the potential economic benefit of valuing them in a more correct way amounts to 3.8 percent of the overall costs of meeting the temperature stabilization target in the base case. In absolute value, this corresponds to an additional net present value cost of US$2000 100 billion. To corroborate our findings we perform a Monte Carlo-analysis where several key parameters are randomly varied simultaneously. The result from this exercise shows that our main result is robust to a wide range of changes in the key parameter values, giving a median economic loss from using GWPs of 4.2 percent

  1. Novel preparation of NaA/carbon nanocomposite thin films with high permeance for CO2/CH4 separation

    Institute of Scientific and Technical Information of China (English)

    Zhi Hui Zhou; Jian Hua Yang; Li Feng Chang; Yan Zhang; Wei Guo Sun; Jin Qu Wang

    2007-01-01

    Novel NaA/carbon nanocomposite thin films were successfully prepared on a porous α-Al2O3 substrate by incorporating nanosized NaA zeolite into novolak-type phenolic resin. The prepared films were characterized by XRD, SEM and single gas permeation tests. The NaA zeolite/carbon nanocomposite thin films exhibited that the ideal separation factor of CO2/CH4 was 28.4and the carbon dioxide flux was 3.39 × 10-7 mol/(Pa m2 s) at room temperature and under a pressure difference of 100 kPa, which was two orders of magnitude higher than that of pure carbon membrane prepared at the same procedures and conditions as those of composite films. From the SEM images, the films were continuous and highly intergrown. Compared with carbon membranes, the thickness of nanocomposite films was drastically decreased, which was helpful to reduce the diffusion resistance and increase the flux of gas permeance.

  2. Low-energy regeneration and high productivity in a lanthanide-hexacarboxylate framework for high-pressure CO2-CH4-H-2 separation

    OpenAIRE

    He, Y.; Furukawa, H.; Wu, C.; O'Keeffe, M; Krishna, R.; Chen, B

    2013-01-01

    A porous lanthanide-organic framework UTSA-62a of a jjt-a topology has been synthesized from a hexacarboxylate and structurally characterized, exhibiting significant potential for use in CO2-CH4-H-2 separation (H-2 purification) processes with high productivities and low regeneration costs when operating at high pressure and room temperature.

  3. Thermodynamic stability, spectroscopic identification, and gas storage capacity of CO2-CH4-N2 mixture gas hydrates: implications for landfill gas hydrates.

    Science.gov (United States)

    Lee, Hyeong-Hoon; Ahn, Sook-Hyun; Nam, Byong-Uk; Kim, Byeong-Soo; Lee, Gang-Woo; Moon, Donghyun; Shin, Hyung Joon; Han, Kyu Won; Yoon, Ji-Ho

    2012-04-01

    Landfill gas (LFG), which is primarily composed of CH(4), CO(2), and N(2), is produced from the anaerobic digestion of organic materials. To investigate the feasibility of the storage and transportation of LFG via the formation of hydrate, we observed the phase equilibrium behavior of CO(2)-CH(4)-N(2) mixture hydrates. When the specific molar ratio of CO(2)/CH(4) was 40/55, the equilibrium dissociation pressures were gradually shifted to higher pressures and lower temperatures as the mole fraction of N(2) increased. X-ray diffraction revealed that the CO(2)-CH(4)-N(2) mixture hydrate prepared from the CO(2)/CH(4)/N(2) (40/55/5) gas mixture formed a structure I clathrate hydrate. A combination of Raman and solid-state (13)C NMR measurements provided detailed information regarding the cage occupancy of gas molecules trapped in the hydrate frameworks. The gas storage capacity of LFG hydrates was estimated from the experimental results for the hydrate formations under two-phase equilibrium conditions. We also confirmed that trace amounts of nonmethane organic compounds do not affect the cage occupancy of gas molecules or the thermodynamic stability of LFG hydrates. PMID:22380606

  4. Pure- and mixed-gas CO2/CH4 separation properties of PIM-1 and an amidoxime-functionalized PIM-1

    KAUST Repository

    Swaidan, Raja

    2014-05-01

    The prototypical solution-processable polymer of intrinsic microporosity, PIM-1, and derivatives thereof offer combinations of permeability and selectivity that make them potential candidate materials for membrane-based gas separations. Paramount to the design and evaluation of PIMs for economical natural gas sweetening is a high and stable CO2/CH4 selectivity under realistic, mixed-gas conditions. Here, amidoxime-functionalized PIM-1 (AO-PIM-1) was prepared and examined for fundamental structure/property relationships. Qualitative NLDFT pore-size distribution analyses of physisorption isotherms (N2 at -196 oC; CO2 at 0 oC) reveal a tightened microstructure indicating size-sieving ultra-microporosity (<7Å). AO-PIM-1 demonstrated a three-fold increase in αD(CO2/CH4) over PIM-1, surpassing the 2008 upper bound with P(CO2)=1153Barrer and ideal α(CO2/CH4)=34. Under a 50:50 CO2:CH4 mixed-gas feed, AO-PIM-1 showed less selectivity loss than PIM-1, maintaining a mixed-gas α(CO2/CH4) ~21 across a 20bar pressure range. Conversely, PIM-1 endured up to 60% increases in mixed-gas CH4 permeability over pure-gas values concurrent with a selectivity of only ~8 at 20bar. A pervasive intermolecular hydrogen bonding network in AO-PIM-1 predominantly yields a rigidified microstructure that mitigates CO2-induced matrix dilations, reducing detrimental mixed-gas CH4 copermeation. © 2014 Elsevier B.V.

  5. Fluxes of CO2, CH4 and N2O from soil of burned grassland savannah of central Africa

    Directory of Open Access Journals (Sweden)

    R. Valentini

    2010-06-01

    Full Text Available Grassland savannah ecosystems subject to frequent fires are considered to have an almost neutral carbon balance, as the C released during burning mostly balance the C fixed by the photosynthetic process. However, burning might modify the net soil-atmosphere exchange of GHGs in the post burning phase so that the radiative balance of the site might shift from neutrality. In the present study the impact of fire on soil fluxes of CO2, CH4 and N2O was investigated in a grassland savannah (Congo Brazzaville where high frequency burning is the typical management form of the region. An area was preserved for one season from annual burning and was used as "unburned" treatment. Two field campaigns were carried on at different time length from the fire event, 1 month, in the middle of the dry season, and 8 months after, at the end of the growing season. CO2, CH4 and N2O fluxes, as well as several soil parameters, were measured in each campaign from burned and unburned plots. Rain events were simulated at each campaign to evaluate magnitude and length of the generated GHG flux pulses. In laboratory experiments, on soil samples from the two treatments, microbial biomass, net N mineralization, net nitrification, N2O, NO and CO2 emissions were analyzed in function of soil water and/or temperature variations. Results showed that fire had a significant effect on GHG fluxes but the effect was transient, as after 8 months differences between treatments were no longer significant. One month after burning CO2 soil emissions were significantly lower in the burned plots, CH4 fluxes were dominated by net emissions rather than net consumption in the unburned area and fire shifted the CH4 flux distribution towards more negative values. No significant effect of fire was observed in the field on N2O fluxes. It was assumed that the low water content was the main limiting factor as in fact laboratory data showed that only above 75% of water saturation, N2O emissions

  6. Compact Solar Spectroscopic Column CO2, CH4, H2O and HOD Observations: Performance Evaluation at TCCON Sites

    Science.gov (United States)

    Butterfield, Z.; Lindenmaier, R.; Dubey, M. K.; Hedelius, J.; Wunch, D.; Wennberg, P. O.; Podolske, J. R.; Iraci, L. T.; Hillyard, P. W.; Hase, F.

    2014-12-01

    Monitoring, reporting and verification (MRV) of natural sources and sinks and anthropogenic emission of carbon dioxide (CO2) and methane (CH4) are crucial to predict climate change and develop transparent accounting policies to contain climate forcing. Remote sensing technologies are beginning to monitor CO2 and CH4 from ground and space (OCO-2 and GOSAT) with solar spectroscopy enabling direct MRV. However, current ground based coverage is sparse due to the need for large and expensive high-resolution spectrometers that are part of the Total Column Carbon Observing Network (TCCON, Bruker 125HR). This limits our MRV and satellite validation abilities, both regionally and globally. There are striking monitoring gaps in Asia, South America and Africa where the CO2 emissions are growing and there is a large uncertainty in fluxes from land use change, biomass burning and rainforest vulnerability. To fill this gap we evaluate the precision, accuracy and stability of our new compact, affordable and easy to use low-resolution spectrometer (Bruker EM27SUN) by comparing it with the much larger high-resolution TCCON instruments for column CO2, CH4, H2O and HOD. Results from Four Corners, Los Alamos, Caltech and Dryden-Armstrong sites show that our EM27SUN captures the variability of the aforementioned constituents very well, but has low and high offsets for CO2 and CH4, respectively. These off-the-shelf spectrometers should dramatically expand the coverage of regional column CO2 and CH4 observations, particularly in gap regions that include the rainforest. We will present opportunities that we are exploring to help enable transparent and reliable MRV and measurement of the coupled water-carbon cycle in tropical ecosystems.

  7. Study of Mix CO2/CH4 Hydrate Phase Transitions vs the Thickness of Surrounding Water Film

    Science.gov (United States)

    Kvamme, B.; Baig, K.; Kuznetsova, T.

    2014-12-01

    Conversion of reservoir CH4 hydrate into CO2 hydrate is an interesting option offering a win-win combination of energy production with safe long-term storage of CO2 to minimize the CO2 footprint. As described theoretically and verified experimentally, CO2 is capable of inducing and maintaining a solid state exchange process of conversion. This mechanism will be slow since it is kinetically controlled by solid state mass transport through the hydrate. In parallel to this, the injected CO2 will form new hydrate from free water trapped in pores. Heat released by this process will contribute to dissociation of in situ CH4 hydrate and thus provide a second conversion mechanism with its rate controlled by liquid state transport processes. Understanding the kinetics of gas hydrate formation and dissociation is crucial for the development of theoretical models describing gas exchange processes and providing a basis for efficient design of production schemes. In this work, we combine a non-equilibrium description of hydrate and fluid thermodynamics with the phase field theory (PFT) for simulation of phase transition kinetics. The phase field theory approach allows one to minimize the free energy while taking into account the implicit couplings to mass and heat transport as well as hydrodynamics. The hydrodynamic treatment is important to distinguish between situations when gas released in the course of dissociation will dissolve into surrounding water (slow dissociation), and more rapid dissociation creating dispersed gas bubbles that will affect the available dissociation interface and influence heat transport. We studied the conversion of CH4 hydrate into either CO2 hydrate or mixed CO2-CH4 hydrate to investigate the relative impact of the two mechanisms. The efficiency of mechanism based on formation of new CO2 hydrate will depend on the contact area between injected CO2 and liquid water. We have therefore investigated three CH4 hydrate systems surrounded by varying

  8. Pure- and Mixed-Gas Permeation Properties of Highly Selective and Plasticization Resistant Hydroxyl-Diamine-Based 6FDA Polyimides for CO2/CH4 Separation

    KAUST Repository

    Alaslai, Nasser

    2016-01-05

    The effect of hydroxyl functionalization on the m-phenylene diamine moiety of 6FDA dianhydride-based polyimides was investigated for gas separation applications. Pure-gas permeability coefficients of He, H2, N2, O2, CH4, and CO2 were measured at 35 °C and 2 atm. The introduction of hydroxyl groups in the diamine moiety of 6FDA-diaminophenol (DAP) and 6FDA-diamino resorcinol (DAR) polyimides tightened the overall polymer structure due to increased charge transfer complex formation compared to unfunctionalized 6FDA-m-phenylene diamine (mPDA). The BET surface areas based on nitrogen adsorption of 6FDA-DAP (54 m2g−1) and of 6FDA-DAR (45 m2g−1) were ~18% and 32% lower than that of 6FDA-mPDA (66 m2g−1). 6FDA-mPDA had a pure-gas CO2 permeability of 14 Barrer and CO2/CH4 selectivity of 70. The hydroxyl-functionalized polyimides 6FDA-DAP and 6FDA-DAR exhibited very high pure-gas CO2/CH4 selectivities of 92 and 94 with moderate CO2 permeability of 11 and 8 Barrer, respectively. It was demonstrated that hydroxyl-containing polyimide membranes maintained very high CO2/CH4 selectivity (~ 75 at CO2 partial pressure of 10 atm) due to CO2 plasticization resistance when tested under high-pressure mixed-gas conditions. Functionalization with hydroxyl groups may thus be a promising strategy towards attaining highly selective polyimides for economical membrane-based natural gas sweetening.

  9. Fluxes of CO2, CH4 and N2O from a temperate forest soil: the effects of leaves and humus layers

    OpenAIRE

    Dong, Y.; D. Scharffe; J. M. Lobert; Crutzen, P. J.; Sanhueza, E.

    2011-01-01

    Fluxes of CO2, CH4, and N2O from forest soils were measured with an enclosed chamber technique between October 1990 and December 1991 in a deciduous forest near Darmstadt, Germany. Flux measurements were made before and after the removal of leaves and humus layer from the forest floor, and gas fluxes from the leaves and humus alone were also measured as well as depth profiles of CH4, N2O, and soil moisture. Except for N2O, large seasonal variations were observed with generally higher gas flux...

  10. Role of intrachain rigidity in the plasticization of intrinsically microporous triptycene-based polyimide membranes in mixed-Gas CO2/CH4 separations

    KAUST Repository

    Swaidan, Raja

    2014-11-11

    Based on high-pressure pure- and mixed-gas (50:50) CO2/CH4 separation properties of two intrinsically microporous triptycene-based polyimides (TPDA-TMPD and TPDA-6FpDA), the intrachain rigidity central to "conventional PIM" design principles is not a singular solution to intrinsic plasticization resistance. Despite the significant intrachain rigidity in TPDA-TMPD, a 300% increase in PMIX(CH4), 50% decrease in α(CO2/CH4) from 24 to 12, and continuous increase in PMIX(CO2) occurred from 4 to 30 bar. On the other hand, the more flexible and densely packed TPDA-6FpDA exhibited a slight upturn in PMIX(CO2) at 20 bar similar to a dense cellulose acetate (CA) film, also reported here, despite a 4-fold higher CO2 sorption capacity. Microstructural investigations suggest that the interconnected O2- and H2-sieving ultramicroporosity of TPDA-TMPD is more sensitive to slight CO2-induced dilations and is the physical basis for a more extensive and accelerated plasticization. Interchain rigidity, potentially by interchain interactions, is emphasized and may be facilitated by intrachain mobility.

  11. Adsorption kinetics of CO2, CH4, and their equimolar mixture on coal from the Black Warrior Basin, West-Central Alabama

    Science.gov (United States)

    Gruszkiewicz, M.S.; Naney, M.T.; Blencoe, J.G.; Cole, D.R.; Pashin, J.C.; Carroll, R.E.

    2009-01-01

    Laboratory experiments were conducted to investigate the adsorption kinetic behavior of pure and mixed gases (CO2, CH4, approximately equimolar CO2 + CH4 mixtures, and He) on a coal sample obtained from the Black Warrior Basin at the Littleton Mine (Twin Pine Coal Company), Jefferson County, west-central Alabama. The sample was from the Mary Lee coal zone of the Pottsville Formation (Lower Pennsylvanian). Experiments with three size fractions (45-150????m, 1-2??mm, and 5-10??mm) of crushed coal were performed at 40????C and 35????C over a pressure range of 1.4-6.9??MPa to simulate coalbed methane reservoir conditions in the Black Warrior Basin and provide data relevant for enhanced coalbed methane recovery operations. The following key observations were made: (1) CO2 adsorption on both dry and water-saturated coal is much more rapid than CH4 adsorption; (2) water saturation decreases the rates of CO2 and CH4 adsorption on coal surfaces, but it appears to have minimal effects on the final magnitude of CO2 or CH4 adsorption if the coal is not previously exposed to CO2; (3) retention of adsorbed CO2 on coal surfaces is significant even with extreme pressure cycling; and (4) adsorption is significantly faster for the 45-150????m size fraction compared to the two coarser fractions. ?? 2008 Elsevier B.V.

  12. Ten years of CO2, CH4, CO and N2O fluxes over Western Europe inferred from atmospheric measurements at Mace Head, Ireland

    Directory of Open Access Journals (Sweden)

    S. G. Jennings

    2008-01-01

    Full Text Available We estimated CO2, CH4, CO and N2O emission fluxes over the British Isles and Western Europe using atmospheric radon observations and concentrations recorded at the Mace Head Atmospheric Research Station between 1996 and 2005. We classified hourly concentration data into either long-range European or regional sources from Ireland and UK, by using local wind speed data in conjunction with 222Rn and 212Pb threshold criteria. This leads to the selection of about 7% of the total data for both sectors. We then used continuous 222Rn measurements and assumptions on the surface emissions of 222Rn to deduce the unknown fluxes of CO2, CH4, CO and N2O. Our results have been compared to the UNFCCC, EMEP and EDGAR statistical inventories and to inversion results for CH4. For Western Europe, we found yearly mean fluxes of 4.1±1.5 106 kg CO2 km−2 yr−1 , 11.9±2.0 103 kg CH4 km−2 yr−1, 12.8±4.2 103 kg CO km−2 yr−1 and 520.2±129.2 kg N2O km−2 yr−1, respectively, for CO2, CH4, CO and N2O over the period 1996–2005. The method based upon 222Rn to infer emissions has many sources of systematic errors, in particular its poorly known and variable footprint, uncertainties in 222Rn soil fluxes and in atmospheric mixing of air masses with background air. However, these biases are likely to remain constant in the long-term, which makes the method quite efficient to detect trends in fluxes. Over the last ten years period, the decrease of the anthropogenic CH4, CO and N2O emissions in Europe estimated by inventories (respectively −30%, −35% and −23% is confirmed by the Mace Head data within 2%. Therefore, the 222Rn method provides an independent way of verification of changes in national emissions derived from inventories. Using European-wide estimates of the CO/CO2 emission ratio, we also found that it is possible to separate the fossil fuel CO2 emissions contribution from the one of total CO2 fluxes. The fossil fuel CO2 emissions and their trends

  13. Three years of vertically resolved CO2/CH4/CO measurements at the tallest tower in the Amazon - Amazonian Tall Tower Observatory (ATTO, Brazil)

    Science.gov (United States)

    Valentin Lavrič, Jošt; Winderlich, Jan; Walter, David; Chi, Xuguang; Andreae, Meinrat O.; Heimann, Martin

    2015-04-01

    The 330 m-tall tower that is currently in its final phase of construction at the Amazonian Tall Tower Observatory (ATTO, Brazil; 2° 08'S, 59° 00'W), is the counterpart of the 304 m-tall tower of the Zotino Tall Tower Observatory tower (ZOTTO), located in central Siberia (Russia; 60° 48'N, 89° 21'E). The ATTO tall tower will extend above the atmospheric surface layer and the nocturnal stable boundary layer, and aims at delivering ground breaking findings that will be the basis for improved climate models. While awaiting the completion of the tall tower, a number of campaign or continuous pilot measurements are taking place on the ATTO site at and around the currently tallest Amazonian tower and mast (80 m a.g.l.). Since March 2012, we run continuous high precision CO2/CH4/CO measurements in an air-conditioned container at the foot of the 80 m tower. The sample air inlets are installed at five levels; 79, 53, 38, 24, and 4 m a.g.l. Two frequently calibrated CRDS analyzers (G1301 and G1302; Picarro Inc., USA) are used for measuring CO2/CH4 and CO/CO2, respectively. Even if due to proximity of our measurements to the canopy (~ 35 m a.g.l.) the data is influenced by local sources and sinks, it still provides a valuable insight into the diurnal and seasonal variations of the measured gas species. Additionally, the data set has proven to be also interesting combined with the parameters that are measured by other groups at the site in parallel either continuously or during intensive observation periods (e.g. VOCs, reactive trace gases, aerosols). A first analysis of the available data is presented. Our work was performed within the frame of the German-Brazilian project ATTO and supported by the federal government agencies BMBF and MCT (Grant number BMBF 01LB1001A). We acknowledge the fundamental support by the Max Planck Society, INPA and UEA. Special thanks go to the Amazonas State SDS/CEUC-RDS Uatumã.

  14. Absolute accuracy and sensitivity analysis of OP-FTIR retrievals of CO2, CH4 and CO over concentrations representative of ''clean air'' and ''polluted plumes''

    Directory of Open Access Journals (Sweden)

    D. W. T. Griffith

    2010-08-01

    Full Text Available When compared to established point-sampling methods, Open-Path Fourier Transform Infrared (OP-FTIR spectroscopy can provide path-integrated concentrations of multiple gases simultaneously, in situ and near-continuously. Concentrations can be retrieved from the measured IR spectra using a forward model coupled to a non-linear least squares fitting procedure, without requiring ''background'' spectral measurements unaffected by the gases of interest. However, few studies have investigated the accuracy of such retrievals for CO2, CH4 and CO, particularly across a broad concentration range covering ambient to highly polluted air (e.g. from biomass burning or industrial plumes. Here we perform such an assessment using data collected by a field-portable FTIR spectrometer. The FTIR was positioned to view a fixed IR source placed at the other end of an IR-transparent cell filled with the gases of interest, whose target concentrations were varied by up to two orders of magnitude. Retrievals made using the forward model are complicated by absorption line pressure broadening, the effects of temperature on absorption band shape and by convolution of the gas absorption lines and the instrument line shape (ILS. Despite this, with optimal forward model parameterisation (i.e. the wavenumber range used in the retrieval, gas temperature, pressure and ILS, concentration retrievals for all gases were able to be made to within 5% of the true value. Sensitivity to the aforementioned model inputs was also investigated. CO retrievals were shown to be most sensitive to the ILS (a function of the assumed instrument FOV, which is due to the narrow nature of CO absorption lines and their consequent sensitivity to convolution with the ILS. Conversely, CO2 retrievals were most sensitive to assumed atmospheric parameters, particularly temperature. The analysis suggests that trace gas concentration retrieval errors can remain well below 10%, even with the uncertainties in

  15. Absolute accuracy and sensitivity analysis of OP-FTIR retrievals of CO2, CH4 and CO over concentrations representative of "clean air" and "polluted plumes"

    Directory of Open Access Journals (Sweden)

    D. W. T. Griffith

    2011-01-01

    Full Text Available When compared to established point-sampling methods, Open-Path Fourier Transform Infrared (OP-FTIR spectroscopy can provide path-integrated concentrations of multiple gases simultaneously, in situ and near-continuously. The trace gas pathlength amounts can be retrieved from the measured IR spectra using a forward model coupled to a non-linear least squares fitting procedure, without requiring "background" spectral measurements unaffected by the gases of interest. However, few studies have investigated the accuracy of such retrievals for CO2, CH4 and CO, particularly across broad concentration ranges covering those characteristic of ambient to highly polluted air (e.g. from biomass burning or industrial plumes. Here we perform such an assessment using data collected by a field-portable FTIR spectrometer. The FTIR was positioned to view a fixed IR source placed at the other end of an IR-transparent cell filled with the gases of interest, whose target concentrations were varied by more than two orders of magnitude. Retrievals made using the model are complicated by absorption line pressure broadening, the effects of temperature on absorption band shape, and by convolution of the gas absorption lines and the instrument line shape (ILS. Despite this, with careful model parameterisation (i.e. the optimum wavenumber range, ILS, and assumed gas temperature and pressure for the retrieval, concentrations for all target gases were able to be retrieved to within 5%. Sensitivity to the aforementioned model inputs was also investigated. CO retrievals were shown to be most sensitive to the ILS (a function of the assumed instrument field-of-view, which is due to the narrow nature of CO absorption lines and their consequent sensitivity to convolution with the ILS. Conversely, CO2 retrievals were most sensitive to assumed atmospheric parameters, particularly gas temperature. Our findings provide confidence that FTIR-derived trace gas retrievals of CO2, CH4 and CO

  16. Small scale soil carbon and moisture gradients in a drained peat bog grassland and their influence on CO2, CH4 and N2O fluxes

    Science.gov (United States)

    Leiber-Sauheitl, K.; Fuß, R.; Freibauer, A.

    2012-04-01

    Due to the UNFCCC report requirements of each country on the emissions of greenhouse gases from key sources the joint research project "Organic Soils" was established in Germany. The project's objective is to improve the data set on greenhousegas emissions from organic soils in Germany. Within 12 German Project Catchments emissions from different types of organic soils, e.g. under different land uses and hydrological conditions, are measured. At the location "Großes Moor" near Gifhorn (Lower Saxony) the effects of small-scale soil organic carbon and groundwater level gradients on the GHG fluxes (CO2, CH4 and N2O) are quantified. The study area is located within a former peat bog altered by drainage and peat cutting, which is currently grassland under extensive agricultural use. The focus of the study is on the acquisition of CO2, CH4 and N2O fluxes on six sites via manual closed chambers. In order to calculate the annual CO2 exchange rate, values are interpolated on a 0.5 hour scale between measurement campaigns. In combination with continually logged meteorological parameters, such as the photosynthetic active radiation as well as air and soil temperatures, we calculate the daily CO2 ecosystem exchange of the different sites. During the 2011 campaign, CO2 was determined as the most important greenhouse gas. The groundwater table was the dominant variable influencing gas emissions. Another important factor was the vegetation composition. In detail, highest CO2 emissions occurred with a water table of 40-50 cm below ground level, temperatures above 10°C and low plant biomass amounts. Due to the more complex formation of N2O by a number of processes, each being promoted by different soil conditions, the measurement of N2O fluxes in the field was complemented by a laboratory experiment. In this, the use of stable isotope tracer techniques enabled us to quantify the contribution of single biochemical pathways to the overall formation of N2O under controlled

  17. AC plasma torch with a H2O/CO2/CH4 mix as the working gas for methane reforming

    International Nuclear Information System (INIS)

    This paper presents results of investigations implemented during construction of the three-phase ac plasma torch working on a mixture of steam with carbon dioxide and methane (H2O/CO2/CH4) with power upto 120 kW. Such thermal plasma generators are needed in industrial technologies for methane reforming with the aim of producing the syngas comprising of the hydrogen and carbon mono-oxide (H2/CO). It was shown that during plasma torch work there are two character parts of the high-voltage arc. In these parts, the arc column has a different diameter and temperature about (8.5  −  8.3) · 103 K and (10.5  −  10.0) · 103 K, respectively. The plasma torch output characteristics have been obtained for working regimes with various flow rates of the methane (0.0–0.8 g s−1) in the plasma-forming mix and constant flow rates of the carbon dioxide and water steam (each of 3.0 g s−1). For the mentioned mix of gases, the unit generates plasma with the mass-average temperature ∼(3.2–3.3) · 103K and the thermal efficiency ∼94–96%. This provides effective reforming of methane. (paper)

  18. Frequency Comb Spectroscopy of CO(2), CH(4), H(2)O, and Isotopes Over a 2 km Outdoor Path: Concentration Retrievals Using Different Absorption Models

    Science.gov (United States)

    Rieker, G. B.; Giorgetta, F. R.; Coddington, I.; Swann, W. C.; Zolot, A. M.; Sinclair, L. C.; Baumann, E.; Cromer, C.; Newbury, N.

    2014-06-01

    A dual frequency comb spectrometer is used to make high signal-to-noise measurements of atmospheric absorption from 5990 to 6260 cm-1 with 0.0033 cm-1 point spacing and ˜4·10-8 cm-1 resolution over a 2 km outdoor air path. The spectra, which encompass over 700 absorption features of CO2, CH4, and H2O, are fit with several absorption models to assess the quality of the models and to retrieve the various species concentrations and air temperature. The models tested include the HITRAN 2008 and 2012 spectral databases with Voigt line-shape profiles as well as a recent model for CO2 that includes the effects of line mixing and speed dependence. Residuals are typically less than 2% of the peak absorbance, except for the HITRAN 2012 CH4 model, which exhibits larger residuals. Species concentration retrievals using the models are compared with a calibrated point sensor mounted on a tower near the open air path.

  19. Technical Note: Latitude-time variations of atmospheric column-average dry air mole fractions of CO2, CH4 and N2O

    Directory of Open Access Journals (Sweden)

    M. Rettinger

    2012-08-01

    Full Text Available We present a comparison of an atmospheric general circulation model (AGCM-based chemistry-transport model (ACTM simulation with total column measurements of CO2, CH4 and N2O from the Total Carbon Column Observing Network (TCCON. The model is able to capture observed trends, seasonal cycles and inter hemispheric gradients at most sampled locations for all three species. The model-observation agreements are best for CO2, because the simulation uses fossil fuel inventories and an inverse model estimate of non-fossil fuel fluxes. The ACTM captures much of the observed seasonal variability in CO2 and N2O total columns (~81 % variance, R>0.9 between ACTM and TCCON for 19 out of 22 cases. These results suggest that the transport processes in troposphere and stratosphere are well represented in ACTM. Thus the poor correlation between simulated and observed CH4 total columns, particularly at tropical and extra-tropical sites, have been attributed to the uncertainties in surface emissions and loss by hydroxyl radicals. While the upward-looking total column measurements of CO2 contains surface flux signals at various spatial and temporal scales, the N2O measurements are strongly affected by the concentration variations in the upper troposphere and stratosphere.

  20. Greenhouse Gas Emissions (CO2-CH4 From Municipal Solid Waste Management Using Life Cycle Assessment (LCA in Mahdsht City (IRAN

    Directory of Open Access Journals (Sweden)

    Naderi M

    2014-08-01

    Full Text Available Waste production is inevitable in any society and consequently waste management is one of the main roles of any municipality. Therefore, it is necessary to evaluate different waste management scenarios. According to the amount and composition of the generated waste, considering environmental, economic and technical issues, several options are existed. Life Cycle Assessment (LCA as a decision support tool has been used in several cases to select the most appropriate option. In this paper, production of greenhouse gases (CO2-CH4 in different waste management options in Mahdasht city (Iran has been studied using IWM software and LCA application. Two scenarios has been defined, the first includes direct and complete transferring of waste to the landfill, and the second includes transferring of 76% of total waste to the landfill and recycling 20% and composting 4%. The questionnaires were fulfilled by the staffs and field surveying. The life cycle inventory cataloging was done using the IWM-1model according to environmental point of view. The amount of produced greenhouse gases in the first scenario is about 9,218 tons and in the second scenario is about 6,801 tons. Results indicate that implementing recycling and composting operation can lead to the 26% reduction in greenhouse gas emissions and energy consumption reduction of a waste management system.

  1. Effects of hydroxyl-functionalization and sub-Tg thermal annealing on high pressure pure- and mixed-gas CO2/CH4 separation by polyimide membranes based on 6FDA and triptycene-containing dianhydrides

    KAUST Repository

    Swaidan, Raja

    2015-02-01

    A sub-Tg thermally-annealed (250°C, 24h) ultra-microporous PIM-polyimide bearing a 9,10-diisopropyl-triptycene contortion center and hydroxyl-functionalized diamine (2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane, APAF) exhibited plasticization resistance up to 50bar for a 1:1 CO2/CH4 feed mixture, with a 9-fold higher CO2 permeability (30Barrer) and 2-fold increase in CO2/CH4 permselectivity (~50) over conventional dense cellulose acetate membranes at 10bar CO2 partial pressure. Interestingly, mixed-gas CO2/CH4 permselectivities were 10-20% higher than those evaluated under pure-gas conditions due to reduction of mixed-gas CH4 permeability by co-permeation of CO2. Gas transport, physisorption and fluorescence studies indicated a sieving pore-structure engaged in inter-chain charge transfer complexes (CTCs), similar to that of low-free-volume 6FDA-APAF polyimide. The isosteric heat of adsorption of CO2 as well as CO2/CH4 solubility selectivities varied negligibly upon replacement of OH with CH3 but CTC formation was hindered, CO2 sorption increased, CO2 permeability increased ~3-fold, CO2/CH4 permselectivity dropped to ~30 and CH4 mixed-gas co-permeation increased. These results suggest that hydroxyl-functionalization did not cause preferential polymer-gas interactions but primarily elicited diffusion-dominated changes owing to a tightened microstructure more resistant to CO2-induced dilations. Solution-processable hydroxyl-functionalized PIM-type polyimides provide a new platform of advanced materials that unites the high selectivities of low-free-volume polymers with the high permeabilities of PIM-type materials particularly for natural gas sweetening applications.

  2. Beyond the Methanogenic Black-Box: Greenhouse Gas Fluxes (CO2, CH4, N2O) as Evidence for Wetlands as Dynamic Redox Systems

    Science.gov (United States)

    Mcnicol, G.; Knox, S. H.; Sturtevant, C. S.; Baldocchi, D. D.; Silver, W. L.

    2015-12-01

    Seminal wetland research in the 1990s demonstrated that annual methane (CH4) fluxes scaled positively with ecosystem production across distinctive wetlands globally. This relationship implies a model of flooded wetland ecosystems as 'methanogenic black-boxes'; poised at a low redox state, and tending to release a fixed fraction of incoming annual productivity as CH4. In contrast, recent studies have reported high ratios of carbon dioxide (CO2) to CH4 emissions, and are adding to a body of evidence suggesting wetlands can vary more widely in their redox state. To explore this apparent incongruence we used principles of redox thermodynamics and laboratory experiments to develop predictions of wetland greenhouse gas (GHG) fluxes under different redox regimes. We then used a field study to test the hypothesis that ecosystem seasonality in gross primary productivity (GPP) and temperature would drive changes in GHG emissions, mediated by a dynamic - as opposed to static - redox regime. We estimated wetland GHG emissions from an emergent marsh in the Sacramento Delta, CA from March 2014-2015. We measured CO2, CH4 and N2O emissions via diffusion and ebullition with manual sampling, and whole-ecosystem fluxes of CO2 and CH4 using eddy-covariance. Ebullition and diffusive CH4 fluxes were strongly seasonal, with minimum rates (0.86 and 0.35 mg C-CH­­4 m-2 yr-1, respectively) during winter, and maximum rates (1.3 and 1.8 g C-CH­­4 m-2 yr-1, respectively) during the summer growing season. In contrast, winter diffusive CO2 fluxes (494 g C-CO2 m-2 yr-1) and fall bubble CO2 concentrations (1.49%) were highest, despite being seasons of lower GPP, temperature, and CH4 flux. Further, diffusive and ebullition fluxes of N2O showed zero net flux only during spring and summer months, whereas the wetland was a significant source of N2O during winter (81.2 ± 24.4 mg N-N2O m-2 yr-1). These seasonal flux dynamics contradict a 'methanogenic black box' model of wetland redox, which

  3. Ground-based, integrated path differential absorption LIDAR measurement of CO2, CH4, and H2O near 1.6  μm.

    Science.gov (United States)

    Wagner, Gerd A; Plusquellic, David F

    2016-08-10

    A ground-based, integrated path, differential absorption light detection and ranging (IPDA LIDAR) system is described and characterized for a series of nighttime studies of CO2, CH4, and H2O. The transmitter is based on an actively stabilized, continuous-wave, single-frequency external-cavity diode laser (ECDL) operating from 1.60 to 1.65 μm. The fixed frequency output of the ECDL is microwave sideband tuned using an electro-optical phase modulator driven by an arbitrary waveform generator and filtered using a confocal cavity to generate a sequence of 123 frequencies separated by 300 MHz. The scan sequence of single sideband frequencies of 600 ns duration covers a 37 GHz region at a spectral scan rate of 10 kHz (100 μs per scan). Simultaneously, an eye-safe backscatter LIDAR system at 1.064 μm is used to monitor the atmospheric boundary layer. IPDA LIDAR measurements of the CO2 and CH4 dry air mixing ratios are presented in comparison with those from a commercial cavity ring-down (CRD) instrument. Differences between the IPDA LIDAR and CRD concentrations in several cases appear to be well correlated with the atmospheric aerosol structure from the backscatter LIDAR measurements. IPDA LIDAR dry air mixing ratios of CO2 and CH4 are determined with fit uncertainties of 2.8 μmol/mol (ppm) for CO2 and 22 nmol/mol (ppb) for CH4 over 30 s measurement periods. For longer averaging times (up to 1200 s), improvements in these detection limits by up to 3-fold are estimated from Allan variance analyses. Two sources of systematic error are identified and methods to remove them are discussed, including speckle interference from wavelength decorrelation and the seed power dependence of amplified spontaneous emission. Accuracies in the dry air retrievals of CO2 and CH4 in a 30 s measurement period are estimated at 4 μmol/mol (1% of ambient levels) and 50 nmol/mol (3%), respectively. PMID:27534472

  4. Diffuse soil emission of hydrothermal gases (CO2, CH4, and C6H6) at Solfatara crater (Campi Flegrei, southern Italy)

    International Nuclear Information System (INIS)

    Highlights: • We present the first measurements of soil C6H6 fluxes in a volcanic system. • Methane oxidation rate is controlled by soil gas fluxes. • Benzene oxidation rate is controlled by presence of a SO42-rich aquifer. • Fumarolic emissions cause a strong benzene air contamination at a local scale. • Endogenous monoaromatics are detected in air samples from the whole crater. - Abstract: Measurements of soil fluxes of hydrothermal gases, with special emphasis on C6H6, as well as chemical composition of mono-aromatic compounds in fumaroles and air, were carried out in April 2012 at the Solfatara crater (Campi Flegrei, Southern Italy) to investigate the distribution and behavior of these species as they migrate through the soil from their deep source to the atmosphere. Soil fluxes of CO2, CH4 and C6H6 exhibit good spatial correlation, suggesting that diffuse degassing is mainly controlled by local fractures. The calculated total output of diffuse C6H6 from Solfatara is 0.10 kg day−1, whereas fluxes of CO2 and CH4 are 79 × 103 and 1.04 kg day−1, respectively. A comparison between soil gas fluxes and fumarole composition reveals that within the crater soil CH4 is significantly affected by oxidation processes, which are more efficient for low gas fluxes, being dependent on the residence time of the uprising hydrothermal gases at shallow depth. Benzene degradation, mainly proceeding through oxidation via benzoate, seems to be strongly controlled by the presence of a shallow SO42-rich aquifer located in the central and southwestern sectors of the crater, suggesting that the process is particularly efficient when SO42- acts as terminal electron acceptor (SO4 reduction). Relatively high C6H6/C7H8 ratios, typical of hydrothermal fluids, were measured in air close to the main fumarolic field of Solfatara crater. Here, C6H6 concentrations, whose detection limit is ∼0.1 μg m−3, are more than one order of magnitude higher than the limit value for ambient

  5. Fragilariopsis kerguelensis response to iron enrichment regarding its growth, uptake of nutrients and trace metals, and changes in CO2, CH4, and N2O

    Science.gov (United States)

    Kwon, Young Shin; Rhee, Tae Siek; Kim, Sun Young; Kim, Mi Seon; Choi, Man Sik; Yang, Eun Jin; Kim, Young-Nam

    2014-12-01

    We performed laboratory experiments to investigate the response of Fragilariopsis kerguelensis, a predominant diatom species in the Southern Ocean, to different concentrations of dissolved iron in the culture medium to assess changes in nutrients, trace metals, and greenhouse gases-CO2, CH4, and N2O-during growth. F. kerguelensis was cultured in standard f/2+Si media contained in closed chambers at 2℃, which is a typical surface temperature of the Southern Ocean in summer, under continuous irradiation with ~44 μmol photons m-2 s-1 for 8 days. The media contained 2.2 nM, 7.0 nM, and 10.6 nM of dissolved iron at inoculation. F. kerguelensis grew faster if the initial dissolved iron concentration was higher. Its production rate was ~40 cells mL-1 d-1 with an increase of 10-18 molar dissolved iron on a single cell basis. Fe and Mo were consumed faster than the growth rate at higher dissolved iron concentrations while Mn and Zn were consumed more slowly taking the mean values into account. Nitrate consumption by single cells increased with an increase of dissolved iron in the media, but phosphate and silicate showed a tendency to decrease. Hence, dissolved iron enhanced uptake of nitrate, but not the other nutrients, on a single cell basis. The carbon uptake per cell decreased with an increase in dissolved iron, which is opposite to the growth rate, suggesting that carbon content in single cells could not keep up with the cell growth. The iron efficacy of carbon uptake by single cells, defined as the ratio of the carbon uptake to the iron uptake, also showed a significant reduction with an increase in dissolved iron. This implies the inefficient usage of iron to absorb carbon at a high dissolved iron concentration. CH4 uptake by F. kerguelensis occurred in our experiments, but it was trivial in relation to the overall impact. N2O was consumed at a lower concentration of dissolved iron, but was emitted at a higher dissolved iron concentration, suggesting a facultative

  6. High pressure pure- and mixed-gas separation of CO2/CH4 by thermally-rearranged and carbon molecular sieve membranes derived from a polyimide of intrinsic microporosity

    KAUST Repository

    Swaidan, Raja

    2013-11-01

    Natural gas sweetening, one of the most promising venues for the growth of the membrane gas separation industry, is dominated by polymeric materials with relatively low permeabilities and moderate selectivities. One strategy towards improving the gas transport properties of a polymer is enhancement of microporosity either by design of polymers of intrinsic microporosity (PIMs) or by thermal treatment of polymeric precursors. For the first time, the mixed-gas CO2/CH4 transport properties are investigated for a complete series of thermally-rearranged (TR) (440°C) and carbon molecular sieve (CMS) membranes (600, 630 and 800°C) derived from a polyimide of intrinsic microporosity (PIM-6FDA-OH). The pressure dependence of permeability and selectivity is reported up to 30bar for 1:1, CO2:CH4 mixed-gas feeds at 35°C. The TR membrane exhibited ~15% higher CO2/CH4 selectivity relative to pure-gas feeds due to reductions in mixed-gas CH4 permeability reaching 27% at 30bar. This is attributed to increased hindrance of CH4 transport by co-permeation of CO2. Interestingly, unusual increases in mixed-gas CH4 permeabilities relative to pure-gas values were observed for the CMS membranes, resulting in up to 50% losses in mixed-gas selectivity over the applied pressure range. © 2013 Elsevier B.V.

  7. Fluxes of CO2, CH4 and N2O from alpine grassland in the Tibetan Plateau%青藏高原高寒草原生态系统CO2,CH4和N2O排放通量研究

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Using static chamber technique, fluxes of CO2, CHh and N2O were measured in the alpinegrassland area from July 2000 to July 2001, determinations of mean fluxes showed that CO2 and N2Owere generally released from the soil, while the alpine grassland accounted for a weak CH4 sink.Fluxes of CO2, CH4 and N2O ranged widely. The highest CO2 emission occurred in August, whereasalmost 90% of the whole year emission occurred in the growing season. But the variations of CH4and N2O fluxes did not show any clear patterns over the one-year-experiment. During a dailyvariation, the maximum CO2 emission occurred at 16:00, and then decreased to the minimumemission in the early morning. Daily pattern analyses indicated that the variation in CO2 fluxes waspositively related to air temperatures (R2=0.73) and soil temperatures at a depth of 5 cm (R2=4).86),whereas daily variations in CH4 and N2O fluxes were poorly explained by soil temperatures andclimatic variables. CO2 emissions in this area were much lower than other grasslands in plain areas.

  8. Spatial variability of greenhouse gases emissions (CO2, CH4, N2O) in a tropical hydroelectric reservoir flooding primary forest (Petit Saut Reservoir, French Guiana)

    Science.gov (United States)

    Cailleaud, Emilie; Guérin, Frédéric; Bouillon, Steven; Sarrazin, Max; Serça, Dominique

    2014-05-01

    At the Petit Saut Reservoir (PSR, French Guiana, South America), vertical profiles were performed at 5 stations in the open waters (OW) and 6 stations in two shallow flooded forest (FF) areas between April 2012 and September 2013. Measurements included physico-chemical parameters, ammonium, nitrate and dissolved greenhouse gas (CO2, CH4, N2O) concentrations, dissolved and particulate organic carbon (DOC, POC) and nitrogen (PN), δ13C-POC and δ15N-PN . The diffusive fluxes were calculated from surface concentrations. The aim of this study was to estimate the spatial variations of greenhouse gas emissions at a dentrical hydroelectric reservoir located in the tropics and flooding primary forest. Twenty years after impoundment, the water column of the PSR is permanently and tightly stratified thermally in the FF whereas in the OW, the thermal gradients are not as stable. The different hydrodynamical behaviours between the two different zones have significant consequences on the biogeochemistry: oxygen barely diffuses down to the hypolimnion in the FF whereas destratification occurs sporadically during the rainy season in the OW. Although we found the same range of POC in the FF and the OW (2.5-29 μmol L-1) and 20% more DOC at the bottom of OW than in the FF (229-878 μmol L-1), CO2 and CH4 concentrations were always significantly higher in the FF (CO2: 11-1412 μmol L-1, CH4: 0.001-1015 μmol L-1) than in the OW. On average, the CO2 concentrations were 30-40% higher in the FF than in the OW and the CH4 concentrations were three times higher in the FF than in the OW. The δ13C-POC and C:N values did not suggest substantial differences in the sources of OM between the FF and OW. At all stations, POC at the bottom has an isotopic signature slightly lighter than the terrestrial OM in the surrounding forest whereas the isotopic signature of surface POM would result from phytoplankton and methanotrophs. The vertical profiles of nitrogen compounds reveal that the main

  9. Fluxes of CO2, CH4 and N2O at two European beech forests: linking soil gas production profiles with soil and stem fluxes

    Science.gov (United States)

    Maier, Martin; Machacova, Katerina; Halaburt, Ellen; Haddad, Sally; Urban, Otmar; Lang, Friederike

    2016-04-01

    Soil and plant surfaces are known to exchange greenhouse gases with the atmosphere. Some gases like nitrous oxide (N2O) and methane (CH4) can be produced and re-consumed in different soil depths and soil compartments, so that elevated concentrations of CH4 or N2O in the soil do not necessarily mean a net efflux from the soil into the atmosphere. Soil aeration, and thus the oxygen status can underlay a large spatial variability within the soil on the plot and profile scale, but also within soil aggregates. Thus, conditions suitable for production and consumption of CH4 and N2O can vary on different scales in the soil. Plant surfaces can also emit or take up CH4 and N2O, and these fluxes can significantly contribute to the net ecosystem exchange. Since roots usually have large intercellular spaces or aerenchyma they may represent preferential transport ways for soil gases, linking possibly elevated soil gas concentrations in the subsoil in a "shortcut" to the atmosphere. We tested the hypothesis that the spatial variability of the soil-atmosphere fluxes of CO2, CH4 and N2O is caused by the heterogeneity in soil properties. Therefore, we measured soil-atmosphere gas fluxes, soil gas concentrations and soil diffusivity profiles and did a small scale field assessment of soil profiles on the measurments plots. We further tried to link vertical profiles of soil gas concentrations and diffusivity to derive the production and consumption profiles, and to link these profiles to the stem-atmosphere flux rates of individual trees. Measurements were conducted in two mountain beech forests with different geographical and climatic conditions (White Carpathians, Czech Republic; Black Forest, Germany). Gas fluxes at stem and soil levels were measured simultaneously using static chamber systems and chromatographic and continuous laser analyses. Monitoring simultaneously vertical soil gas profiles allowed to assess the within-soil gas fluxes, and thus to localize the production and

  10. Continuous multi-plot measurements of CO2, CH4, N2O and H2O in a managed boreal forest - The importance of accounting for all greenhouse gases

    Science.gov (United States)

    Vestin, P.; Mölder, M.; Sundqvist, E.; Båth, A.; Lehner, I.; Weslien, P.; Klemedtsson, L.; Lindroth, A.

    2015-12-01

    In order to assess the effects of different management practices on the exchange of greenhouse gases (GHG), it is desirable to perform repeated and parallel measurements on both experimental and control plots. Here we demonstrate how a system system combining eddy covariance and gradient techniques can be used to perform this assessment in a managed forest ecosystem.The net effects of clear-cutting and stump harvesting on GHG fluxes were studied at the ICOS site Norunda, Sweden. Micrometeorological measurements (i.e., flux-gradient measurements in 3 m tall towers) allowed for quantification of CO2, CH4 and H2O fluxes (from May 2010) as well as N2O and H2O fluxes (from June 2011) at two stump harvested plots and two control plots. There was one wetter and one drier plot of each treatment. Air was continuously sampled at two heights in the towers and gas concentrations were analyzed for CH4, CO2, H2O (LGR DLT-100, Los Gatos Research) and N2O, H2O (QCL Mini Monitor, Aerodyne Research). Friction velocities and sensible heat fluxes were measured by sonic anemometers (Gill Windmaster, Gill Instruments Ltd). Automatic chamber measurements (CO2, CH4, H2O) were carried out in the adjacent forest stand and at the clear-cut during 2010.Average CO2 emissions for the first year ranged between 14.4-20.2 ton CO2 ha-1 yr-1. The clear-cut became waterlogged after harvest and a comparison of flux-gradient data and chamber data (from the adjacent forest stand) indicated a switch from a weak CH4 sink to a significant source at all plots. The CH4 emissions ranged between 0.8-4.5 ton CO2-eq. ha-1 yr-1. N2O emissions ranged between 0.4-2.6 ton CO2-eq. ha-1 yr-1. Enhanced N2O emission on the drier stump harvested plot was the only clear treatment effect on GHG fluxes that was observed. Mean CH4 and N2O emissions for the first year of measurements amounted up to 29% and 20% of the mean annual CO2 emissions, respectively. This highlights the importance of including all GHGs when assessing

  11. Greenhouse effect gases sources and sinks (CO2, CH4, N2O) in grasslands and reduction strategies. Greenhouse effect gases prairies. Final report of the second part of the project. April 2004

    International Nuclear Information System (INIS)

    The project 'GES-Prairies' (Greenhouse Gases - Grasslands) had two main objectives: 1. To measure more accurately the fluxes of CO2, CH4 and N2O of French grasslands and determine the greenhouse gas (GHG) balance of these areas. 2. To calculate the net GHG emissions of cattle production farms and finally to propose and evaluate some management scenarios leading to a reduction of GHG emissions. This project deals with three different spatial scales: the field scale, the farm scale and finally, the regional scale. At the field scale, during two years, fluxes of CO2, CH4 and N2O were measured in a mid-mountain permanent grassland, previously managed intensively by cutting and grazing (Laqueuille, Auvergne, France). Results from the first complete year of measurements show that the extensification process (reduction of the stocking rate and stopping N fertilization) allows to stock more carbon in the ecosystem. At the farm scale, We developed a model (FARMSIM, coupled to PASIM) able to simulate the GHG balance of a livestock farm. FARMSIM has been tested with data obtained from a mixed livestock farm in Lorraine (dairy and meat production, annual average stocking rate = 1.3 LU ha-1) of 100 ha (including 76 ha of grasslands and 21 of annual crops). The results indicate a net emission of 175 t equivalent C-CO2 for this farm. If expressed per unit of product, it represents 1.34 t equivalent C-CO2 per LU and per year or 0.54 kg CO2 per kg of milk and per year. At the regional scale/. The PASIM model has been used to simulate the European grasslands with a spatial resolution of 1' (about 200 * 200 km). For each grid cell, a sensibility analysis allowed to determine the N application which correspond to 30% of the N application that would maximize the annual yield of the pasture. Simulation runs on mixed systems (combining grazing and cutting) show that almost one half of the grassland area is, on average, used for cutting. These simulations predict N2O emission factors that

  12. 大气CO2、CH4、CO高精度观测混合标气配制方法%Preparation of mixed standards for high accuracy CO2/CH4/CO measurements

    Institute of Scientific and Technical Information of China (English)

    姚波; 黄建青; 周凌晞; 方双喜; 刘立新; 夏玲君; 李培昌; 王红阳

    2013-01-01

    CO2/CH4/CO mixed standards in dry clean air are critical for high accuracy measurement. Water vapor concentration and 813 C in CO2 can significantly influence optical measurement methods. In this study, a custom-made preparation system was built to prepare the required mixed standards. Ambient air was pressurized into cylinders and target gases were adjusted by filling in high concentration gases or absorption. The absorption efficiencies of ASCARITE Ⅱ and Sofnocat423 were 99.7% and 99. 8% , respectively. Water vapor in the mixing standards was less than 3.7 × 10-6. Seven testing standards were made at Waliguan global background station in Qinghai Province. The deviations of the prepared concentrations from the target concentrations were less than 10 × 10-6, 30 × 10-9 and 30 × 10-9 for CO2, CH4 and CO, respectively. 813 in CO2 was within ambient range in these testing standards. The method has already been employed to produce qualified standards for high accuracy greenhouse gases measurements at Chinese background stations, and these standards met the requirement of World Meteorological Organization/Global Atmosphere Watch ( WMO/ GAW).%高精度、高准确度的大气CO2、CH4、CO浓度观测需使用以干洁大气为底气的标气.标气中水汽含量及CO2的δ13C对基于光学原理的观测系统有不可忽视的影响.本研究利用自组装的混合标气配制系统,以环境大气为底气,并通过添加高浓度气体或利用吸附剂吸附,调节目标物种浓度.CO2和CO吸附效率分别达99.7%和99.8%,标气水汽含量小于3.7×10-6(物质的量分数,下同),可配制不同浓度范围的CO2、CH4、CO混合标气.在青海瓦里关全球大气本底站配制环境大气浓度范围的标气,CO2、CH4、CO实际配制浓度同目标浓度的偏差小于10×10-6、30×10-9、30×10-9,CO2中δ13C同实际大气接近.本方法配制的标气已应用于我国本底站大气CO2、CH4、CO高精度观测,符合世界气象组织/

  13. Aircraft measurements of the concentrations of CO2, CH4, N2O, and CO and the carbon and oxygen isotopic ratios of CO2 in the troposphere over Russia

    Science.gov (United States)

    Nakazawa, Takakiyo; Sugawara, Satoshi; Inoue, Gen; Machida, Toshinobu; Makshyutov, Shamil; Mukai, Hitoshi

    1997-02-01

    About 370 air samples were collected using aircraft in the troposphere over Russia in the summers of 1992, 1993, and 1994. These were then analyzed for the CO2, CH4, N2O and CO concentrations, as well as for δ13C and δ18O of CO2. Measured vertical profiles of tropospheric CO2 showed that the concentration increased with height over all locations. In the lower troposphere over the wetland and taiga regions, extremely low CO2 concentrations of 335-345 parts per million by volume (ppmv) were often observed. Measured values of δ13C and the CO2 concentration were negatively correlated with each other, the rate of change in δ13C with respect to the CO2 concentration being about -0.05‰/ppmv. This implies that the variations in the CO2 concentration observed over Russia in the summer are primarily caused by terrestrial biospheric activities. In the middle and upper troposphere, the CO2 concentration and δ13C showed systematic differences between each other in 1992, 1993, and 1994, probably due to their secular changes. The δ18O and CO2 observed in the lowest part of the troposphere over east and west Siberia were also negatively correlated with each other, with the rate of change in δ18O with respect to CO2 estimated to be about -0.1 l‰/ppmv. This relation may be caused by isotopic equilibrium of oxygen in CO2 with soil water through respiration of living plants and decomposition of organic matter and with chloroplast water in leaves through photosynthesis of living plants. In contrast to CO2, the CH4 concentration decreased with height. Extremely high CH4 concentrations were observed over the west Siberian lowland, owing to a large amount of CH4 emitted from wetlands. The N2O concentrations were fairly constant through the troposphere over all locations covered by this study, with an average value of about 311 parts per billion by volume (ppbv). The CO concentrations also showed vertical profiles, with a small gradient over natural wetlands, taiga, and tundra

  14. Characterization of trace gases measured over Alberta oil sands mining operations: 76 speciated C2–C10 volatile organic compounds (VOCs, CO2, CH4, CO, NO, NO2, NOy, O3 and SO2

    Directory of Open Access Journals (Sweden)

    A. J. Weinheimer

    2010-08-01

    Full Text Available Oil sands comprise 30% of the world's oil reserves and the crude oil reserves in Canada's oil sands deposits are second only to Saudi Arabia. The extraction and processing of oil sands is much more challenging than for light sweet crude oils because of the high viscosity of the bitumen contained within the oil sands and because the bitumen is mixed with sand and contains chemical impurities such as sulphur. Despite these challenges, the importance of oil sands is increasing in the energy market. To our best knowledge this is the first peer-reviewed study to characterize volatile organic compounds (VOCs emitted from Alberta's oil sands mining sites. We present high-precision gas chromatography measurements of 76 speciated C2–C10 VOCs (alkanes, alkenes, alkynes, cycloalkanes, aromatics, monoterpenes, oxygenates, halocarbons, and sulphur compounds in 17 boundary layer air samples collected over surface mining operations in northeast Alberta on 10 July 2008, using the NASA DC-8 airborne laboratory as a research platform. In addition to the VOCs, we present simultaneous measurements of CO2, CH4, CO, NO, NO2, NOy, O3 and SO2, which were measured in situ aboard the DC-8. Methane, CO, CO2, NO, NO2, NOy, SO2 and 53 VOCs (e.g., halocarbons, sulphur species, NMHCs showed clear statistical enhancements (up to 1.1–397× over the oil sands compared to local background values and, with the exception of CO, were higher over the oil sands than at any other time during the flight. Twenty halocarbons (e.g., CFCs, HFCs, halons, brominated species either were not enhanced or were minimally enhanced (4–C9 alkanes, C5–C6 cycloalkanes, C6–C8 aromatics, together with CO; and (2 emissions associated with the mining effort (i.e., CO2, CO, CH4, NO, NO2, NOy, SO2, C2–C4 alkanes, C2–C4 alkenes, C9 aromatics, short-lived solvents such as C2Cl4 and C2HCl3, and longer-lived species such as HCFC-22 and HCFC-142b. Prominent in the second group, SO2 and NO were

  15. Characterization of trace gases measured over Alberta oil sands mining operations: 76 speciated C2-C10 volatile organic compounds (VOCs), CO2, CH4, CO, NO, NO2, NOy, O3 and SO2

    Science.gov (United States)

    Simpson, I. J.; Blake, N. J.; Barletta, B.; Diskin, G. S.; Fuelberg, H. E.; Gorham, K.; Huey, L. G.; Meinardi, S.; Rowland, F. S.; Vay, S. A.; Weinheimer, A. J.; Yang, M.; Blake, D. R.

    2010-12-01

    Oil sands comprise 30% of the world's oil reserves and the crude oil reserves in Canada's oil sands deposits are second only to Saudi Arabia. The extraction and processing of oil sands is much more challenging than for light sweet crude oils because of the high viscosity of the bitumen contained within the oil sands and because the bitumen is mixed with sand and contains chemical impurities such as sulphur. Despite these challenges, the importance of oil sands is increasing in the energy market. To our best knowledge this is the first peer-reviewed study to characterize volatile organic compounds (VOCs) emitted from Alberta's oil sands mining sites. We present high-precision gas chromatography measurements of 76 speciated C2-C10 VOCs (alkanes, alkenes, alkynes, cycloalkanes, aromatics, monoterpenes, oxygenated hydrocarbons, halocarbons and sulphur compounds) in 17 boundary layer air samples collected over surface mining operations in northeast Alberta on 10 July 2008, using the NASA DC-8 airborne laboratory as a research platform. In addition to the VOCs, we present simultaneous measurements of CO2, CH4, CO, NO, NO2, NOy, O3 and SO2, which were measured in situ aboard the DC-8. Carbon dioxide, CH4, CO, NO, NO2, NOy, SO2 and 53 VOCs (e.g., non-methane hydrocarbons, halocarbons, sulphur species) showed clear statistical enhancements (1.1-397×) over the oil sands compared to local background values and, with the exception of CO, were greater over the oil sands than at any other time during the flight. Twenty halocarbons (e.g., CFCs, HFCs, halons, brominated species) either were not enhanced or were minimally enhanced (local background, respectively. These SO2 levels are comparable to maximum values measured in heavily polluted megacities such as Mexico City and are attributed to coke combustion. By contrast, relatively poor correlations between CH4, ethane and propane suggest low levels of natural gas leakage despite its heavy use at the surface mining sites. Instead

  16. CO_2、CH_4和N_2在不同硅铝比β沸石上的吸附分离性能%Adsorption separation of CO_2, CH_4 and N_2 on β-zeolite with different SiO_2/Al_2O_3 ratios

    Institute of Scientific and Technical Information of China (English)

    徐晓亮; 赵兴祥; 孙林兵; 刘晓勤

    2009-01-01

    The adsorption separation of CO_2, CH_4 and N_2 was studied via volumetric measurements of t3-zeolite samples with different SiO_2/Al_2O_3 ratios at 273 and 303 K. Results showed that all the obtained adsorption isotherms are well correlated with the Langmuir-Freundlich model. For a certain sample, the adsorption capacity for CO_2 is much higher than that for CH_4 and N_2. The adsorption capacity for CO_2 increases with the decrease in SiO_2/Al_2O_3 ratio under same temperature and pressure. The Henry law's constant and adsorption equilibrium selectivity of CO_2, CH_4, and N_2 on different β-zeolite samples were calculated via Virial equation, showing that the β-zeolite samples have higher equilibrium selectivity for CO_2 over N_2 and CH_4. The selectivity of CO_2 over N_2 and CH_4 increases with the decrease in SiO_2/Al_2O_3 ratio. Therefore, the β-zeolite sample with a low SiO_2/Al_2O_3 ratio is a good candidate for the separation of carbon dioxide from its mixture with methane and nitrogen. The isosteric adsorption heat for CO_2, CH_4 and N_2 calculated by Clausius-Clapeyron equation is independent with the increase of adsorption loading, which indicates that β-zeolite is an energetically homogenous adsorbent.%采用体积法在273 K和303 K温度下对CO_2,CH_4和N_2在不同硅/铝比的β沸石上的吸附分离性能进行了研究.实验结果表明,Langmuir-Freundlich模型能够较好地拟合吸附实验数据;同一样品上,CO_2的吸附量要大于CH_4和N_2的吸附量;随着硅铝比的减小CO_2的吸附量增加,而硅/铝比对CH_4和N_2的吸附量的影响较小.通过结合Virial方程计算CO_2、CH_4和N_2在不同硅/铝比β沸石上的亨利定律常数和吸附选择性,发现所研究样品对CO_2/CH_4和CO_2/N_2均具有很高的吸附选择性,随着样品硅/铝比的减小,CO_2/CH_4和CO_2/N_2的吸附选择性显著增加,说明较低硅/铝比β沸石有利于分离CO_2.用Clausius-Ciapeyron方程求得CO_2,CH_4和N_2在不

  17. Research on Relationship Among CO2, CH4 and N2O Emission Fluxes in Freshwater Marsh Ecosystem%沼泽湿地生态系统CO2、CH4和N2O排放通量的相互关系研究

    Institute of Scientific and Technical Information of China (English)

    卢妍; 徐洪文; 宋长春

    2011-01-01

    利用静态暗箱/气相色谱法连续两个生长季(2003 -2004年)对三江平原小叶章草甸和毛果苔草沼泽CO2、CH4和N2O的排放通量进行野外原位观测.结果表明:两种类型湿地的生长季均为温室气体的排放源,三种温室气体排放通量之间的关系是,CO2和CH4、CO2和N2O、CH4和N2O排放通量之间均为正相关,但显著性水平视不同湿地类型以及不同年份而异.表明它们之间的相互关系受湿地类型以及环境因素的影响,本研究结果迸一步证明了植物在沼泽湿地温室气体排放中的关键性作用.%CO2, CH4 and N2O fluxes were measured using the technique of closed opaque chamber and gas chromatography system. The experiment was carried out during 2003-2004 growing seasons in field of Calamagrostis angustifoli meadow and Carex lasiocarpa marsh in the Sanjiang Plain. The results showed that the two wetlands both were emission sources of greenhouse gases during growing seasons. There was a positively significant correlation between CO2 and CH4 emission fluxes, CO2 and N2O emission fluxes, and CH4 and N2O emission fluxes. But the level was different in various wetlands or years. It indicated that the relationship was influenced by wetland types and environmental factors. It was proved further that plants played a key role in greenhouse gases emission in freshwater marsh ecosystem.

  18. 北极新奥尔松地区夏季近地面CO2、CH4和N2O浓度的观测研究%SPATIAL AND TEMPORAL VARIATIONS IN CO2, CH4 AND N2O CONCENTRATION IN NY-(A)LESUND, SVALBARD

    Institute of Scientific and Technical Information of China (English)

    陈清清; 朱仁斌; 徐华

    2013-01-01

    not show evidently higher atmospheric concentrations of CO2,CH4 and N2O concentration.%2008和2009年夏在北极新奥尔松地区(Ny-(A)lesund)不同苔原区域(鸟类保护区、海滩苔原、矿区、人类活动区等)监测CO2、CH4和N2O近地面浓度的时空变化并分析其可能的影响因素.2008年7月25日-8月13日和2009年7月13-26日,在不同观测区域设置常规和非常规采样点采集气体样品共239瓶并妥善保存.实验室内使用气相色谱(GC)测定准确真空瓶中温室气体(CO2、CH4和N2O)的浓度.鸟类保护区的日变化中,2008年鸟类保护区CO2和N2O日变化浓度均大于2009年约30 ppm和25 ppb.2008年海滩苔原CO2浓度均高于2009年约30 ppm;N2O浓度低于2009年11 ppb;2008年鸟类保护区CH4浓度低于2009年,而海滩苔原2008年浓度高于2009年,差值均约为0.7 ppm.这些年际变化可能由环境条件(天气变化等)和地表覆盖情况的变化引起.高海鸟活动区(HB) CO2浓度低于海鸟活动较少的区域(MB和LB);鸟类保护区CO2浓度低于海滩苔原,N2O浓度高于海滩苔原,主要原因是海鸟活动和鸟粪增加了土壤营养元素,影响苔藓植被发育并改变苔原土壤上垫面的覆盖状况.综合不同苔原区域:新奥尔松地区CO2和CH4浓度高于ZEP (Zeppelin Station)监测平均浓度,地表向大气输送CO2和CH4;而N2O低于ZEP监测的平均浓度,地表从大气吸收N2O.不同区域影响因素不同:鸟类保护区、海滩苔原和鸟岛主要是受到海鸟活动影响;矿区主要是受水分和土壤基质影响;站区和机场受到人类活动影响但并不明显,总的来说直接原因是由于地表覆盖情况以及地形不同引起.

  19. CO2, CH4 and particles flux measurements in Florence, Italy

    Science.gov (United States)

    Gioli, Beniamino; Toscano, Piero; Zaldei, Alessandro; Fratini, Gerardo; Miglietta, Franco

    2013-04-01

    We report a synthesis of seven years of eddy covariance (EC) flux measurements in the city of Florence, Italy. The measurement site is located in a densely urbanized area in the central city area, where fluxes are governed by anthropogenic emissions, considering the lack of green-space in the flux footprint. EC flux measurements of CO2 are made long-term since seven years, while short-term campaigns have been aimed at measuring CH4 and particles fluxes. CO2 and CH4 densities are measured with fast open-path sensors, while particles in the range 0.32 - 7.00 µm optical diameter are measured with a custom-built optical counter. CO2 long-term fluxes are always a net source, with a small inter-annual variability associated with a high seasonality, ranging from 39 to 172% of the mean annual value in summer and winter respectively. CH4 fluxes to the atmosphere are relevant, representing about 8% of CO2-equivalent emissions, and do not exhibit any significant seasonality. Relative contributions of road traffic and domestic heating to observed emissions has been estimated through multi-variate analysis combined with inventorial data and emission proxies such as traffic counters and gas network flow rates, revealing that domestic heating accounts for more than 80% of observed CO2 fluxes. Heating and road traffic are instead responsible for only 14% of observed CH4 fluxes, while the major residual part is likely dominated by gas network leakages. Particles flux data show a smaller seasonal trend and a pronounced weekend decrease, highlighting that the contribution of heating to particle emissions is relatively small compared to road traffic. Dynamics at hourly time scales during week and week-end days allows the analysis of the coupled role of emission strength and atmospheric processes such as advection and entrainment in regulating atmospheric concentrations. This set of observations highlights the potential of urban EC flux measurements as a validation tool for inventorial based estimates, and as a planning and verification tool for emission reduction policies that may be applied by city administrators. Challenges and limitations of EC in urban environments are finally highlighted.

  20. Etude des melanges co-continus d'acide polylactique et d'amidon thermoplastique (PLA/TPS)

    Science.gov (United States)

    Chavez Garcia, Maria Graciela

    Les melanges co-continus sont des melanges polymeriques ou chaque composant se trouve dans une phase continue. Pour cette raison, les caracteristiques de chacun des composants se combinent et il en resulte un materiau avec une morphologie et des proprietes particulieres. L'acide polylactique (PLA) et l'amidon thermoplastique (TPS) sont des biopolymeres qui proviennent de ressources renouvelables et qui sont biodegradables. Dans ce projet, differents melanges de PLA et TPS a une haute concentration de TPS ont ete prepares dans une extrudeuse bi-vis afin de generer des structures co-continues. Grace a la technique de lixiviation selective, le TPS est enleve pour creer une structure poreuse de PLA qui a pu etre analysee au moyen de la microtomographie R-X et de la microscopie electronique a balayage MEB. L'analyse des images 2D et 3D confirme la presence de la structure co-continue dans les melanges dont la concentration en TPS. se situe entre 66% et 80%. L'effet de deux plastifiants, le glycerol seul et le melange de glycerol et de sorbitol, dans la formulation de TPS est etudie dans ce travail. De plus, nous avons evalue l'effet du PLA greffe a l'anhydride maleique (PLAg) en tant que compatibilisant. On a trouve que la phase de TPS obtenue avec le glycerol est plus grande. L'effet de recuit sur la taille de phases est aussi analyse. Grace aux memes techniques d'analyse, on a etudie l'effet du procede de moulage par injection sur la morphologie. On a constate que les pieces injectees presentent une microstructure heterogene et differente entre la surface et le centre de la piece. Pres de la surface, une peau plus riche en PLA est presente et les phases de TPS y sont allongees sous forme de lamelles. Plus au centre de la piece, une morphologie plus cellulaire est observee pour chaque phase continue. L'effet des formulations sur les proprietes mecaniques a aussi ete etudie. Les pieces injectees dont la concentration de TPS est plus grande presentent une moindre

  1. Estimating ice-melange properties with repeat UAV surveys over Store Glacier, West Greenland

    Science.gov (United States)

    Toberg, Nick; Ryan, Johnny; Christoffersen, Poul; Snooke, Neal; Todd, Joe; Hubbard, Alun

    2016-04-01

    In the past decade, tidewater outlet glaciers of the Greenland ice sheet (GrIS) have thinned and retreated when compared to the 1980s when the ice sheet was in a state of dynamic balance. With a growing amount of ice discharged into the sea by tidewater glaciers as well as more ice melting on the surface, the Greenland Ice Sheet has become the single largest cryospheric source of global sea level rise. Today, the ice sheet causes sea level rise of 1 mm per year, highlighting the need to understand the ice sheet's response to climate change. Atmospheric warming will inevitably continue to increase surface meltwater production, but the dynamic response, which includes hundreds of fast-flowing tidewater glaciers, is largely unknown. To develop new understanding of ice sheet dynamics, we investigated the mechanism whereby icebergs break off tidewater glaciers and form a proglacial ice melange. This melange is rigid in winter when sea ice and friction along the sidewalls of the fjord, or even at the sea floor, hold it together. The result is a resistive force, which reduces the rate of iceberg calving when the ice melange is rigid and is lost when the melange disappears in the summer. From early May to late July 2014, we launched unmanned aerial vehicles (UAVs) from a basecamp on a bluff overlooking the calving front of Store Glacier, a 5 km wide tidewater glacier flowing into Uummannaq Fjord in West Greenland. The Skywalker X8 UAVs had a wing-span of 2.1m and a payload containing a high resolution camera, an autopilot system and a GPS data logger. We generated almost 70,000 georeferenced images during 63 sorties over the glacier during a 10 week field season starting 13 May 2014. The images were used to construct orhorectified mosaics and digital elevation models of the proglacial melange with Photoscan structure-from-motion software. The imagery and the DEMs were analysed statistically to understand the spatial characteristics of the ice melange. By combining the

  2. Controls on accretion of flysch and melange belts at convergent margins: evidence from the Chugach Bay thrust and Iceworm melange, Chugach accretionary wedge, Alaska

    Science.gov (United States)

    Kusky, T.M.; Bradley, D.C.; Haeussler, P.J.; Karl, S.

    1997-01-01

    Controls on accretion of flysch and melange terranes at convergent margins are poorly understood. Southern Alaska's Chugach terrane forms the outboard accretionary margin of the Wrangellia composite terrane, and consists of two major lithotectonic units, including Triassic-Cretaceous melange of the McHugh Complex and Late Cretaceous flysch of the Valdez Group. The contact between the McHugh Complex and the Valdez Group on the Kenai Peninsula is a tectonic boundary between chaotically deformed melange of argillite, chert, greenstone, and graywacke of the McHugh Complex and a less chaotically deformed melange of argillite and graywacke of the Valdez Group. We assign the latter to a new, informal unit of formational rank, the Iceworm melange, and interpret it as a contractional fault zone (Chugach Bay thrust) along which the Valdez Group was emplaced beneath the McHugh Complex. The McHugh Complex had already been deformed and metamorphosed to prehnite-pumpellyite facies prior to formation of the Iceworm melange. The Chugach Bay thrust formed between 75 and 55 Ma, as shown by Campanian-Maastrichtian depositional ages of the Valdez Group, and fault-related fabrics in the Iceworm melange that are cut by Paleocene dikes. Motion along the Chugach Bay thrust thus followed Middle to Late Cretaceous collision (circa 90-100 Ma) of the Wrangellia composite terrane with North America. Collision related uplift and erosion of mountains in British Columbia formed a submarine fan on the Farallon plate, and we suggest that attempted subduction of this fan dramatically changed the subduction/accretion style within the Chugach accretionary wedge. We propose a model in which subduction of thinly sedimented plates concentrates shear strains in a narrow zone, generating melanges like the McHugh in accretionary complexes. Subduction of thickly sedimented plates allows wider distribution of shear strains to accommodate plate convergence, generating a more coherent accretionary style

  3. A measurement system for continuous observations of CO2, CH4, H2O and CO onboard passenger aircraft

    Science.gov (United States)

    Gerbig, Christoph; Filges, Annette; Franke, Harald; Klaus, Christoph; Chen, Huilin

    2013-04-01

    Improved quantification and understanding of surface-atmosphere exchange fluxes of greenhouse gases (GHGs) caused by natural as well as anthropogenic processes is of paramount importance in a world of a changing climate and ever increasing emissions. Top-down estimation of GHG fluxes is traditionally done by inverse transport modeling, using GHG observations from a global network of stations. Uncertainties in modeled vertical transport rates (moist convection, turbulent mixing, stratosphere-troposphere exchange) however greatly affect the quality of flux estimates. More recently, remote sensing of vertical column mole fractions of GHGs have become available for inverse modeling, reducing the impact of vertical transport uncertainties to first order. However, those need validation against in-situ observations. A strategy for regular, global in-situ atmospheric profiling of GHGs, covering at least the troposphere, is thus needed to provide validation of remote sensing and of forward transport modeling of GHGs, to serve as input for inverse modeling, and to reduce the impact of transport uncertainties. IAGOS-ERI (In-service Aircraft for a Global Observing System - European Research Infrastructure) exploits the synergy between globally operating civil aviation and the need for long-term monitoring of atmospheric composition. Within the framework of IAGOS-ERI a cavity ring-down spectroscopy (CRDS) based measurement system for greenhouse gases was designed, tested, and qualified for deployment on commercial airliners. The design meets requirements regarding physical dimensions (size, weight), performance (long-term stability, low maintenance, robustness, full automation) and safety issues (fire prevention regulations, airworthiness). The system uses components of a commercially available CRDS instrument (G2401-m, Picarro Inc.) mounted into a frame suitable for integration in the avionics bay of the Airbus A-340. The first of the IAGOS GHG packages is scheduled for integration in mid 2013. The aim is to have seven systems operational within four years, providing for long-term GHG observations with near-global coverage. To enable robust and automated operation of the IAGOS GHG package over six-month deployment periods, numerous technical issues had to be addressed. An inlet system, designed as virtual impactor to eliminate sampling of larger aerosols, ice particles, and water droplets, provides additional positive ram-pressure to ensure operation without an upstream sampling pump. Furthermore, no sample drying is required, as the simultaneously measured water vapor mole fraction is used to correct for dilution and spectroscopic effects. This also enables the collection of science-quality water vapor measurements throughout the atmosphere. To allow for trace gas measurements to be fully traceable to WMO scales, a two-standard calibration system has been designed and tested that periodically provides calibration gas to the instrument during flight and on ground for each six-month deployment period. We present results from recent test flights and laboratory tests that document the performance for GHG and water vapor measurements. Furthermore, future applications of the IAGOS-GHG data stream, provided in near-real-time via SatCom to the weather prediction centres, will be discussed.

  4. Temporal and spatial variations of soil CO2, CH4 and N2O fluxes at three differently managed grasslands

    Directory of Open Access Journals (Sweden)

    D. Imer

    2013-09-01

    Full Text Available A profound understanding of temporal and spatial variabilities of soil carbon dioxide (CO2, methane (CH4 and nitrous oxide (N2O fluxes between terrestrial ecosystems and the atmosphere is needed to reliably quantify these fluxes and to develop future mitigation strategies. For managed grassland ecosystems, temporal and spatial variabilities of these three soil greenhouse gas (GHG fluxes occur due to changes in environmental drivers as well as fertilizer applications, harvests and grazing. To assess how such changes affect soil GHG fluxes at Swiss grassland sites, we studied three sites along an altitudinal gradient that corresponds to a management gradient: from 400 m a.s.l. (intensively managed to 1000 m a.s.l. (moderately intensive managed to 2000 m a.s.l. (extensively managed. The alpine grassland was included to study both effects of extensive management on CH4 and N2O fluxes and the different climate regime occurring at this altitude. Temporal and spatial variabilities of soil GHG fluxes and environmental drivers on various timescales were determined along transects of 16 static soil chambers at each site. All three grasslands were N2O sources, with mean annual soil fluxes ranging from 0.15 to 1.28 nmol m−2 s−1. Contrastingly, all sites were weak CH4 sinks, with soil uptake rates ranging from −0.56 to −0.15 nmol m−2 s−1. Mean annual soil and plant respiration losses of CO2, measured with opaque chambers, ranged from 5.2 to 6.5 μmol m−2 s−1. While the environmental drivers and their respective explanatory power for soil N2O emissions differed considerably among the three grasslands (adjusted r2 ranging from 0.19 to 0.42, CH4 and CO2 soil fluxes were much better constrained (adjusted r2 ranging from 0.46 to 0.80 by soil water content and air temperature, respectively. Throughout the year, spatial heterogeneity was particularly high for soil N2O and CH4 fluxes. We found permanent hot spots for soil N2O emissions as well as locations of permanently lower soil CH4 uptake rates at the extensively managed alpine site. Including hot spots was essential to obtain a representative mean soil flux for the respective ecosystem. At the intensively managed grassland, management effects clearly dominated over effects of environmental drivers on soil N2O fluxes. For CO2 and CH4, the importance of management effects did depend on the status of the vegetation (LAI.

  5. Quantifying the role of Northern Eurasia in global CO2, CH4, and water dynamics during the 21st Century

    Science.gov (United States)

    Zhuang, Qianlai; Kicklighter, David; Cai, Yongxia; Tchebakova, Nadja; Melillo, Jerry; Reilly, John; Sokolov, Andrei; Sirin, Andrey

    2015-04-01

    The largest increase of surface air temperature and related climate extremes have occurred in Northern Eurasia in recent decades, and are projected to continue during the 21st century. The changing climate will affect biogeography, land cover and biogeochemical cycles in the region, which in turn, will affect how global land use evolves in the future as humans attempt to mitigate and adapt to climate change. Regional land-use changes, however, also depend on pressures imposed by the global economy and environmental changes. Feedbacks from future land-use change will further modify regional and global biogeochemistry and climate. This study uses a suite of linked biogeography, biogeochemical, economic, and climate models to explore how climate-induced vegetation shifts in Northern Eurasia will influence land-use change and carbon cycling across the globe during the 21st century. We find that, at the global scale, while more land will be allocated towards food and biofuel crops due to increasing population and associated economic development, the climate-induced vegetation shifts in Northern Eurasia also significantly affect global land use and result in a global cumulative carbon sink of about 63 Pg C under the policy scenario that limits CO2-equivelent greenhouse gas concentrations to 480 ppmv by the end of the 21st century. In comparison with the policy scenario, under a no-policy scenario where CO2-equivelent greenhouse gas concentrations reach 870 ppmv by the end of 21st century, the global cumulative carbon sink is 11 Pg C less mainly due to carbon lost from global grasslands. Cumulative evapotranspiration from global terrestrial ecosystems considering global land-use changes with vegetation shifts in northern Eurasia is 8.05 and 8.35 million km3 for the policy and no-policy scenarios, respectively. In the presentation, we will also discuss our analysis on CH4 emissions from northern Eurasia in response to the changes of land cover and climate during this century.

  6. Global greenhouse gas (CO2, CH4) and carbon monoxide column data products retrieved from SCIAMACHY/ENVISAT

    International Nuclear Information System (INIS)

    Full text: Carbon dioxide (CO2) and methane (CH4) are the two most important anthropogenic greenhouse gases and carbon monoxide (CO) is an important air pollutant. SCIAMACHY on ENVISAT is the first satellite instrument whose measurements are sensitive to concentration changes of these 'carbon gases' at all atmospheric altitude levels down to the Earth's surface where their source/sink signals are largest. Data products for all three gases covering the first three years of ENVISAT (2003-2005) have been generated using the WFM-DOAS scientific retrieval algorithm developed at the University of Bremen. These data products form part of the ESA PROMOTE and EU GEMS climate change and air quality related services. The data sets will be presented and discussed focusing on a comparison with global model simulations. (author)

  7. Development and performance evaluation of Polydimethyl siloxane/Polysulfone (PDMS/PSF) composite membrane for CO2/CH4 separation

    Science.gov (United States)

    Suleman, M. S.; Lau, K. K.; Yeong, Y. F.

    2016-06-01

    Asymmetric polysulfone (PSF) membrane was developed by phase inversion in this study. Polysulfone (PSF) membrane was modified to develop a composite polymeric membrane. Polydimethyl siloxane (PDMS) was used to modify the PSF membrane. PDMS/PSF composite membrane was developed by dip coating of PDMS over PSF. Developed membranes were characterized in terms of membrane morphology by scanning electron microscope (SEM). Micro structure of polysulfone (PSF) membrane confirmed that developed membrane was asymmetric. Dense PDMS coating in microstructure of composite membrane was observed. Membrane swelling experiments were performed by immersing developed membranes in water for specific time period. PDMS/PSF composite membrane resisted water swelling as compared to PSF membrane. Performance of the membrane was evaluated before and after swelling within the pressure range of 2-10 bar. Reasonable decrement in permeance and selectivity was observed after membrane swelling. Thus, membrane swelling affected the separation performance of both PSF and PDMS/PSF composite membrane by decreasing the permeance and selectivity values.

  8. Thermodynamic and kinetic aspects of CO2 capture by hydrate crystallization: application on a CO2-CH4 mixture

    International Nuclear Information System (INIS)

    The CO2 capture using gas hydrate crystallisation is a rupture technology to recover CO2 from gas emitted by industry. The goal is to find cheaper energy solutions to sequester CO2 than conventional processes (amine absorption and TSA / PSA processes). The objective is to study the thermodynamic and kinetic conditions of a process to capture CO2 by the formation of gas hydrates. Gas hydrates have properties of selectivity and a large storage capacity for a separation of gas. The thermodynamic aspects were to determine the phase diagrams to see the feasibility of this technique. We showed that the operating pressures may be important in cases where the liquid phase is only made up of water. To reduce compression costs, we used the TBAB (Tetra-Butyl-Ammonium-Bromide) as an additive. The use of this additive can reduce considerably the operating pressures by 16. However, this pressure gain is accompanied by a loss of storage capacity. We also showed that the model of Van der Waals and Platteeuw is able to describe the phase diagrams obtained. The effect of TBAB on the gas solubility is also determined with different behaviours depending of the gas. For the kinetic part, we showed experimentally a preferential consumption of CO2 in the first moments of the crystallization. A kinetic model based on material and population balances adapted for gas mixtures is proposed. The model describes well the evolution of total gas consumption and the phenomenon of preferential consumption of CO2 at the beginning of the crystallization. This model with good kinetic parameters is able to monitor the size of crystals which is an important feature for transportation aspects of gas hydrates. (author)

  9. Tiber delta CO2-CH4 degassing: A possible hybrid, tectonically active Sediment-Hosted Geothermal System near Rome

    Science.gov (United States)

    Ciotoli, G.; Etiope, G.; Marra, F.; Florindo, F.; Giraudi, C.; Ruggiero, L.

    2016-01-01

    Fiumicino town in the Tiber River delta, near Rome International Airport (Italy), is historically affected by large amounts of carbon dioxide (CO2) in the ground and gas eruptions triggered by shallow drilling. While it is known that CO2 originates from carbonate thermometamorphism and/or mantle degassing, the origin of methane (CH4) associated with CO2 is uncertain and the outgassing spatial distribution is unknown. Combining isotope gas geochemistry, soil gas, and structural-stratigraphic analyses, we provide evidence for a hybrid fluid source system, classifiable as Sediment-Hosted Geothermal System (SHGS), where biotic CH4 from sedimentary rocks is carried by deep geothermic CO2 through active segments of a half-graben. Molecular and isotopic composition of CH4 and concentration of heavier alkanes (ethane and propane), obtained from gas vents and soil gas throughout the delta area, reveal that thermogenic CH4 (up to 3.7 vol% in soil gas; δ13CCH4: -37 to -40‰ VPDB-Vienna Peedee Belemnite, and δ2HCH4: -162 to -203‰ VSMOW - Vienna Standard Mean Ocean Water in gas vents) prevails over possible microbial and abiotic components. The hydrocarbons likely result from known Meso-Cenozoic petroleum systems of the Latium Tyrrhenian coast. Overmaturation of source rocks or molecular fractionation induced by gas migration are likely responsible for increased C1/C2+ ratios. CO2 and CH4 soil gas anomalies are scattered along NW-SE and W-E alignments, which, based on borehole, geomorphologic, and structural-stratigraphic analyses, coincide with active faults of a half-graben that seems to have controlled the recent evolution of the Tiber delta. This SHGS can be a source of considerable greenhouse gas emissions to the atmosphere and hazards for humans and buildings.

  10. N balance and greenhouse gas emissions (CO2, CH4, N2O) in soil with shallow groundwater

    OpenAIRE

    Cocco, Elisa

    2013-01-01

    The work here presented deals with the effects that N, applied with manure, and the water regimes had in a cropping maize system. The study want to evaluate the N leaching trough groundwater and the potential greenhouse gas emission affecting global warming. Two different water regimes were studied: soil in free drainage conditions with different irrigation levels and two shallow water table conditions. The study was conducted in the Experimental Farm of Padua University. Continuous maize...

  11. Field evidence for fault controlled intrusion of blue-schist-bearing melange into an accretionary wedge, Island Mountain, California

    Energy Technology Data Exchange (ETDEWEB)

    Lamons, R.

    1985-01-01

    Two lithologic units of the Franciscan are well exposed along a loop of the Eel River at Island Mountain. They are 1) zeolite or lower grade lithic graywackes, and 2) a 0.5 km wide band of black shaly melange containing blueschist, chert, greenstone, metagraywacke, and a graywacke-hosted copper deposit. Sedimentary features were not observed in the melange. The graywacke was subdivided on the basis of presence or absence of sodium-cobaltonitrate stained K-spar. Field relationships suggest that the blueschist-bearing melange was emplaced along steep NW-dipping faults in an accretionary wedge. Mapping of S. Jewett Rock and SW Lake Mountain quadrangles show narrow anastomosing bands of the melange following NW-trending faults. East of this band, graywackes without K-spar are folded along NW/SE axes. No folds were found to the west. Other Melange bands pinch out into faults which juxtapose graywackes of different facies. The sheared melange bands are not folded and shale beds in the graywacke show little shear so the melange bands are unlikely to be sheared olistostromes. The areal extent of graywacke is about ten times that of melange shales. Assuming this pattern continues laterally and at depth, the amount of ductile material in the melange is far less than that assumed by Cloos (1982) in his flow model for melange. The ductile melange may have been forced upward by metamorphically produced volatiles, or as a result of relative plate motion. It originated at depth, moved up along the top of a subducting slab, plucking clasts, then splayed upward into pre-existing faults in the accretionary wedge.

  12. elaboration de polymere a empreinte moleculaire destine au developpement d'un capteur des pesticides.

    OpenAIRE

    belladgham, wahiba

    2016-01-01

    Dans le present travail , notre interet s'est porté sur l'elaboration des materiaux a empreinte moleculaire MIP destines au developpement dun capteur des pesticides danc notre cas , la synthese du MIP s'est faite en polymerisant sous irradiation UV , LE MELANGE CONSTITUE .

  13. Supported Pd-Au Membrane Reactor for Hydrogen Production: Membrane Preparation, Characterization and Testing

    Directory of Open Access Journals (Sweden)

    Adolfo Iulianelli

    2016-05-01

    Full Text Available A supported Pd-Au (Au 7wt% membrane was produced by electroless plating deposition. Permeation tests were performed with pure gas (H2, H2, N2, CO2, CH4 for long time operation. After around 400 h under testing, the composite Pd-Au membrane achieved steady state condition, with an H2/N2 ideal selectivity of around 500 at 420 °C and 50 kPa as transmembrane pressure, remaining stable up to 1100 h under operation. Afterwards, the membrane was allocated in a membrane reactor module for methane steam reforming reaction tests. As a preliminary application, at 420 °C, 300 kPa of reaction pressure, space velocity of 4100 h−1, 40% methane conversion and 35% hydrogen recovery were reached using a commercial Ni/Al2O3 catalyst. Unfortunately, a severe coke deposition affected irreversibly the composite membrane, determining the loss of the hydrogen permeation characteristics of the supported Pd-Au membrane.

  14. Late Mesozoic and possible early Tertiary accretion in western Washington State: the Helena-Haystack melange and the Darrington- Devils Mountain fault zone

    Science.gov (United States)

    Tabor, R.W.

    1994-01-01

    The Helena-Haystack melange (HH melange) and coincident Darrington-Devils Mountain fault zone (DDMFZ) in northwestern Washington separate two terranes, the northwest Cascade System (NWCS) and the western and eastern melange belts (WEMB). The two terranes of Paleozoic and Mesozoic rocks superficially resemble each other but record considerable differences in structural and metamorphic history. The HH melange is a serpentinite-matrix melange containing blocks of adjacent terranes but also exotic blocks. The HH melange must have formed between early Cretaceous and late middle Eocene time, because it contains tectonic clasts of early Cretaceous Shuksan Greenschist and is overlain by late middle Eocene sedimentary and volcanic rocks. The possible continuation of the DDMFZ to the northwest as the San Juan and the West Coast faults on Vancouver Island suggests that the structure has had a major role in the emplacement of all the westernmost terranes in the Pacific Northwest. -from Author

  15. Characterization of freeze-dried egg melange long stored after irradiation

    International Nuclear Information System (INIS)

    During the 4-year period of storage at room temperature of the freeze-dried (control group) and the freeze-dried and gamma-irradiated (2.0 and 3.5 kGy) whole hen's egg melange, no significant changes were found into the sensory and functional characteristics till the 28th month. The change in the number of SH groups was not unidirectional up to the 28th month and then it started to decrease in all investigated samples. During the entire period of investigation the amount of malondialdehyde in all three groups of egg melange was considerably below the allowed limit for foodstuffs. The most significant fractions of the protein spectra showed a general tendency of decrease during the storage

  16. Studies on genesis of chromite and PGE in Naein ophiolite melange

    Directory of Open Access Journals (Sweden)

    Reza Shamsipour Dehkordi

    2011-10-01

    Full Text Available Nain ophiolite melange is located 140 Km east of Isfahan. Based on the geological studies, this area belongs to Mesozoic ophiolite of Urumieh – Dokhtar zone, west of central Iran. Country rocks are pridotite and serpentinized pridotite. The pridotite rocks are composed of Harzburgite, Lherzolite and replacement Dunite which is belong to spinel pridotite facies. Paragenesis of ore minerals are Chromite, Irarsite, Magnetite, Hematite, Pentlandite, Millerite, Chalcopyrite, Pyrite, and Covelline. Geochemical surveys of host rock and chromite show tholeiite series of magma and alpine type chromite. PGE (Ir, Pt, Pd, and Os are enriched in chromite. REE spider diagram pattern show the processes of boninitic magma and partial melting.

  17. Comprehensive laboratory and field testing of cavity ring-down spectroscopy analyzers measuring H2O, CO2, CH4 and CO

    Science.gov (United States)

    Yver Kwok, C.; Laurent, O.; Guemri, A.; Philippon, C.; Wastine, B.; Rella, C. W.; Vuillemin, C.; Truong, F.; Delmotte, M.; Kazan, V.; Darding, M.; Lebègue, B.; Kaiser, C.; Xueref-Rémy, I.; Ramonet, M.

    2015-09-01

    To develop an accurate measurement network of greenhouse gases, instruments in the field need to be stable and precise and thus require infrequent calibrations and a low consumption of consumables. For about 10 years, cavity ring-down spectroscopy (CRDS) analyzers have been available that meet these stringent requirements for precision and stability. Here, we present the results of tests of CRDS instruments in the laboratory (47 instruments) and in the field (15 instruments). The precision and stability of the measurements are studied. We demonstrate that, thanks to rigorous testing, newer models generally perform better than older models, especially in terms of reproducibility between instruments. In the field, we see the importance of individual diagnostics during the installation phase, and we show the value of calibration and target gases that assess the quality of the data. Finally, we formulate recommendations for use of these analyzers in the field.

  18. Calculation of CO2,CH4 and H2S Solubilities in Aquenous Electrolyte Solution at High Prssure and High Temperature

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    This paper reports an investigation into the characterisation of liquid-vapor electrolyte solutions at high pressure and high temperature,A procedure to enable calculations of methane,carbon dioxide and hydrogen sulphide solubilities in brines(0-6m.) for temperature from 25 to 350℃ and for pressures from 1 to 1800 bar is presented.The model is based on Helgeson,Kirkham and Flowers modified equations of state(HKF)and on the semi-empirical interaction model introduced by Pitzer,HKF modified equations of state are used to calculate the reference fugacity of gas species,and the Pitzer ionic interaction model is used to calculate the activity coefficient of dissolved species(i.e.ionic or neutral).The efficiency of the combination of the two models is confirmed by several comparisons with data in the literature.

  19. The IAGOS GHG package: a measurement system for continuous airborne observations of CO2, CH4, H2O and CO

    Science.gov (United States)

    Gerbig, C.; Filges, A.; Franke, H.; Klaus, C.; Chen, H.

    2012-12-01

    A cavity ring-down spectroscopy (CRDS) based measurement system for greenhouse gases was designed, tested, and qualified for deployment on commercial airliners within the IAGOS-ERI (In-service Aircraft for a Global Observing System - European Research Infrastructure) project. The design meets requirements regarding physical dimensions (size, weight), performance (long term stability, low maintenance, robustness, full automation) and safety issues (fire prevention regulations). The system uses components of a commercially available CRDS instrument (G2401-m, Picarro Inc.) integrated in a frame suitable for integration in the avionics bay of the Airbus A-340. The first of the IAGOS GHG packages is scheduled for integration in early 2013. The aim is to have seven systems operational within four years, providing for long-term GHG observations with near-global coverage. To enable robust and automated operation of the IAGOS GHG package over six-month deployment periods, numerous technical issues had to be addressed. An inlet system, designed as virtual impactor to eliminate sampling of larger aerosols, ice particles, and water droplets, and provides additional positive ram-pressure. In combination with a lowered sample flow of 0.1 slpm, this ensures a fully controlled sample pressure in the cavity of 140 torr throughout the aircraft altitude operating range up to 12.5 km without the need of an upstream sampling pump. Furthermore, no sample drying is required, as the simultaneously measured water vapor mole fraction is used to correct for dilution and spectroscopic effects. This also enables the collection of science-quality water vapor measurements throughout the atmosphere. To allow for trace gas measurements to be fully traceable to WMO scales, a two-standard calibration system has been designed and tested that periodically provides calibration gas to the instrument during flight and on ground. A targeted six-month deployment cycle followed by maintenance of the package ensures a safe operation. During maintenance, calibration gases are analysed and replenished, and a functional inspection, followed by replacement of depleted or damaged parts, will be undertaken. Spare instrumentation will be used to provide for year-round GHG measurements on board each aircraft. We present results from recent test flights and laboratory tests that document the performance for GHG and water vapor measurements. Furthermore, future applications of the IAGOS-GHG data stream, provided in near-real-time via SatCom to the weather prediction centres, will be discussed, including the improved estimation of GHG budgets at regional to continental scales, the assessment of vertical transport in atmospheric models through comparison with observed vertical tracer distributions, and the validation of remote sensing measurements of GHGs.

  20. Fighting global warming: The potential of photocatalysis against CO2, CH4, N2O, CFCs, tropospheric O3, BC and other major contributors to climate change

    OpenAIRE

    De Richter, Renaud; Caillol, Sylvain

    2011-01-01

    International audience At the laboratory scale, photocatalysis is a promising method to convert many air pollutants such as nitrogen oxides and volatile organic compounds, to safer products for human health but also environmentally more acceptable, such as nitrate and carbon dioxide. Indoor and industrial applications of photocatalysis to remove local air pollutants from the atmosphere are now numerous. Large scale outdoor applications of photocatalysis started with self-cleaning glass, co...

  1. Differences in the Spatial Variability Among CO2, CH 4, and N 2O Gas Fluxes from an Urban Forest Soil in Japan.

    Science.gov (United States)

    Bellingrath-Kimura, Sonoko Dorothea; Kishimoto-Mo, Ayaka Wenhong; Oura, Noriko; Sekikawa, Seiko; Yonemura, Seichiro; Sudo, Shigeto; Hayakawa, Atsushi; Minamikawa, Kazunori; Takata, Yusuke; Hara, Hiroshi

    2015-02-01

    The spatial variability of carbon dioxide (CO(2)), methane (CH(4)), and nitrous oxide (N(2)O) fluxes from forest soil with high nitrogen (N) deposition was investigated at a rolling hill region in Japan. Gas fluxes were measured on July 25th and December 5th, 2008 at 100 points within a 100 × 100 m grid. Slope direction and position influenced soil characteristics and site-specific emissions were found. The CO(2) flux showed no topological difference in July, but was significantly lower in December for north-slope with coniferous trees. Spatial dependency of CH(4) fluxes was stronger than that of CO(2) or N(2)O and showed a significantly higher uptake in hill top, and emissions in the valley indicating strong influence of water status. N(2)O fluxes showed no spatial dependency and exhibited high hot spots at different topology in July and December. The high N deposition led to high N(2)O fluxes and emphasized the spatial variability. PMID:24736940

  2. Tillage and Fertilizer Application Practices Effects on Greenhouse Gas Flux (CO2, CH4 and N2O) and Yield in a Corn Cropping System

    Science.gov (United States)

    Tillage and fertilization practices used in row crop production are thought to alter greenhouse gas emissions from soil. Thus, a field experiment was conducted at the Sand Mountain Research and Extension Center located in the Appalachian Plateau region of Northeast Alabama on a Hartsells fine sandy ...

  3. Geochemical Monitoring Of The Gas Hydrate Production By CO2/CH4 Exchange In The Ignik Sikumi Gas Hydrate Production Test Well, Alaska North Slope

    Science.gov (United States)

    Lorenson, T. D.; Collett, T. S.; Ignik Sikumi, S.

    2012-12-01

    Hydrocarbon gases, nitrogen, carbon dioxide and water were collected from production streams at the Ignik Sikumi gas hydrate production test well (TD, 791.6 m), drilled on the Alaska North Slope. The well was drilled to test the feasibility of producing methane by carbon dioxide injection that replaces methane in the solid gas hydrate. The Ignik Sikumi well penetrated a stratigraphically-bounded prospect within the Eileen gas hydrate accumulation. Regionally, the Eileen gas hydrate accumulation overlies the more deeply buried Prudhoe Bay, Milne Point, and Kuparuk River oil fields and is restricted to the up-dip portion of a series of nearshore deltaic sandstone reservoirs in the Sagavanirktok Formation. Hydrate-bearing sandstones penetrated by Ignik Sikumi well occur in three primary horizons; an upper zone, ("E" sand, 579.7 - 597.4 m) containing 17.7 meters of gas hydrate-bearing sands, a middle zone ("D" sand, 628.2 - 648.6 m) with 20.4 m of gas hydrate-bearing sands and a lower zone ("C" sand, 678.8 - 710.8 m), containing 32 m of gas hydrate-bearing sands with neutron porosity log-interpreted average gas hydrate saturations of 58, 76 and 81% respectively. A known volume mixture of 77% nitrogen and 23% carbon dioxide was injected into an isolated section of the upper part of the "C" sand to start the test. Production flow-back part of the test occurred in three stages each followed by a period of shut-in: (1) unassisted flowback; (2) pumping above native methane gas hydrate stability conditions; and (3) pumping below the native methane gas hydrate stability conditions. Methane production occurred immediately after commencing unassisted flowback. Methane concentration increased from 0 to 40% while nitrogen and carbon dioxide concentrations decreased to 48 and 12% respectively. Pumping above the hydrate stability phase boundary produced gas with a methane concentration climbing above 80% while the carbon dioxide and nitrogen concentrations fell to 2 and 18% respectively. Pumping below the gas hydrate stability phase boundary occurred in two periods with the composition of the produced gases continually increasing in methane reaching an excess of 96%, along with carbon dioxide decreasing to <1% and nitrogen to ~3%. The isotopic composition of all the gases was monitored. Methane carbon and hydrogen isotopic compositions remained stable throughout the test, while the carbon dioxide carbon became isotopically heavier. Nitrogen isotopic composition remained stable or became slightly isotopically depleted at the later phase of the test. These results imply that the produced methane was not isotopically fractionated, whereas carbon dioxide was fractionated becoming isotopically heavier at the end of each production phase. In addition, water samples were analyzed during the production phase documenting an increase in salinity.

  4. Shipborne solar absorption measurements of CO2, CH4, N2O and CO and comparison with SCIAMACHY WFM-DOAS retrievals

    OpenAIRE

    Warneke, T.; De Beek, R.; M. Buchwitz; Notholt, J.; Schulz, A.; V. Velazco; O. Schrems

    2005-01-01

    CO, CH4, N2O and CO2 were retrieved from high resolution solar absorption spectra obtained during a ship cruise from Capetown to Bremerhaven in January/February 2003 by Fourier Transform Infrared (FTIR) spectroscopy. Precisions of better than 0.5% for the column averaged volume mixing ratios (VMR) of CH4 and CO2 are achieved using of O2 as a reference gas. Shipborne FTIR-measurements of CO and data from SCIAMACHY/ENVISAT retrieved by the Weighting Function Modified Different...

  5. Post-synthetic modification of porphyrin-encapsulating metal-organic materials by cooperative addition of inorganic salts to enhance CO 2/CH 4 selectivity

    KAUST Repository

    Zhang, ZhenJie

    2012-08-21

    Keeping MOM: Reaction of biphenyl-3,4\\',5-tricarboxylate and Cd(NO 3) 2 in the presence of meso-tetra(N-methyl-4-pyridyl) porphine tetratosylate afforded porph@MOM-11, a microporous metal-organic material (MOM) that encapsulates cationic porphyrins and solvent in alternating open channels. Porph@MOM-11 has cation and anion binding sites that facilitate cooperative addition of inorganic salts (such as M +Cl -) in a stoichiometric fashion. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Historical contribution by country of three greenhouse gases (CO2, CH4, N2O) to the climate change and Equity principle

    International Nuclear Information System (INIS)

    The historical contribution by country to climate change can be used as a basis of analysis for a second period of commitments to the burden share. The historical greenhouse gases emission inventory is an important tool to evaluate the common but differentiated responsibilities of groups according to the principle of the UN Framework Convention on Climate Convention (1992). This paper aims to discuss the differences among the meaning of the GHG historical emissions in terms of development patterns and suggests that different weights for different sectors should be taken into account. GHG emissions due to enteric fermentation from domestic livestock, for example, are linked to different regional activities such as food production, cultural expression or even religion meaning, depending on the region analyzed. Emissions due to fossil fuel sector represent in the majority a not feasible consumption pattern in terms of sustainable development

  7. Sensitivity of the boreal forest-mire ecotone CO2, CH4, and N2O global warming potential to rainy and dry weather

    Science.gov (United States)

    Ťupek, Boris; Minkkinen, Kari; Vesala, Timo; Nikinmaa, Eero

    2015-04-01

    In a mosaic of well drained forests and poorly drained mires of boreal landscape the weather events such as drought and rainy control greenhouse gas dynamics and ecosystem global warming potential (GWP). In forest-mire ecotone especially in ecosystems where CO2 sink is nearly balanced with CO2 source, it's fairly unknown whether the net warming effect of emissions of gases with strong radiative forcing (CH4 and N2O) could offset the net cooling effect of CO2 sequestration. We compared the net ecosystem CO2 exchange (NEE) estimated from the carbon sequestrations of forest stands and forest floor CO2 fluxes against CH4 and N2O fluxes of nine forest/mire site types along the soil moisture gradient in Finland. The ground water of nine sites changed between 10 m in upland forests and 0.1 m in mires, and weather during three years ranged between exceptionally wet and dry for the local climate. The NEE of upland forests was typically a sink of CO2, regardless the weather. Though, xeric pine forest was estimated to be a source of CO2 during wet and intermediate year and became a weak sink only in dry year. The NEE of forest-mire transitions ranged between a sink in dry year, while increased stand carbon sequestration could offset the reduced forest floor CO2 emission, and a source in wet year. The NEE of two sparsely forested mires strongly differed. The lawn type mire was balanced around zero and the hummock type mire was relatively strong NEE sink, regardless the weather. Generally, nearly zero N2O emission could not offset the cooling effect of net CH4 sink and net CO2 sink of upland forest and forest-mire transitions. However in sparsely forested mires, with N2O emission also nearly zero, the CH4 emission during wet and intermediate year played important role in turning the net cooling effect of NEE into a net warming. When evaluating GWP of boreal landscapes, undisturbed forest-mire transitions should be regarded as net cooling ecosystems instead of hotspots of net warming.

  8. The IAGOS-core greenhouse gas package : a measurement system for continuous airborne observations of CO2, CH4, H2O and CO

    NARCIS (Netherlands)

    Filges, Annette; Gerbig, Christoph; Chen, Huilin; Franke, Harald; Klaus, Christoph; Jordan, Armin

    2015-01-01

    Within the framework of IAGOS-ERI (In-service Aircraft for a Global Observing System - European Research Infrastructure), a cavity ring-down spectroscopy (CRDS)-based measurement system for the autonomous measurement of the greenhouse gases (GHGs) CO2 and CH4, as well as CO and water vapour was desi

  9. Spatial variability and temporal dynamics of greenhouse gas (CO2, CH4, N2O concentrations and fluxes along the Zambezi River mainstem and major tributaries

    Directory of Open Access Journals (Sweden)

    C. R. Teodoru

    2014-11-01

    Full Text Available Spanning over 3000 km in length and with a catchment of approximately 1.4 million km2, the Zambezi River is the fourth largest river in Africa and the largest flowing into the Indian Ocean from the African continent. As part of a~broader study on the riverine biogeochemistry in the Zambezi River basin, we present data on greenhouse gas (GHG, carbon dioxide (CO2, methane (CH4, and nitrous oxide (N2O concentrations and fluxes collected along the Zambezi River, reservoirs and several of its tributaries during 2012 and 2013 and over two climatic seasons (dry and wet to constrain the interannual variability, seasonality and spatial heterogeneity along the aquatic continuum. All GHGs concentrations showed high spatial variability (coefficient of variation: 1.01 for CO2, 2.65 for CH4 and 0.21 for N2O. Overall, there was no unidirectional pattern along the river stretch (i.e. decrease or increase towards the ocean, as the spatial heterogeneity of GHGs appeared to be determined mainly by the connectivity with floodplains and wetlands, and the presence of man-made structures (reservoirs and natural barriers (waterfalls, rapids. Highest CO2 and CH4 concentrations in the mainstream river were found downstream of extensive floodplains/wetlands. Undersaturated CO2 conditions, in contrast, were characteristic for the surface waters of the two large reservoirs along the Zambezi mainstem. N2O concentrations showed the opposite pattern, being lowest downstream of floodplains and highest in reservoirs. Among tributaries, highest concentrations of both CO2 and CH4 were measured in the Shire River whereas low values were characteristic for more turbid systems such as the Luangwa and Mazoe rivers. The interannual variability in the Zambezi River was relatively large for both CO2 and CH4, and significantly higher concentrations (up to two fold were measured during wet seasons compared to the dry season. Interannual variability of N2O was less pronounced but generally higher values were found during the dry season. Overall, both concentrations and fluxes of CO2 and CH4 were well below the median/average values reported for tropical rivers, streams and reservoirs. A first-order mass balance suggests that carbon (C transport to the ocean represents the major component (59% of the budget (largely in the form of DIC, while only 38% of total C yield is annually emitted into the atmosphere, mostly as CO2 (98%, and 3% is removed by sedimentation in reservoirs.

  10. Greenhouse Gas Emissions (CO2-CH4) From Municipal Solid Waste Management Using Life Cycle Assessment (LCA) in Mahdsht City (IRAN)

    OpenAIRE

    Naderi M; Salari Baghon Abad M; Amiri M; Rezazadeh M

    2014-01-01

    Waste production is inevitable in any society and consequently waste management is one of the main roles of any municipality. Therefore, it is necessary to evaluate different waste management scenarios. According to the amount and composition of the generated waste, considering environmental, economic and technical issues, several options are existed. Life Cycle Assessment (LCA) as a decision support tool has been used in several cases to select the most appropriate option. In this paper, pro...

  11. The net GHG (CO2, CH4 and N2O) footprint of a newly impounded subtropical hydroelectric reservoir: Nam Theun 2

    Science.gov (United States)

    Deshmukh, Chandrashekhar; Guérin, Frédéric; Delon, Claire; Pighini, Sylvie; Vongkhamsao, Axay; Descloux, Stéphane; Chanudet, Vincent; Tardif, Raphael; Godon, Arnaud; Guédant, Pierre; Galy-Lacaux, Corinne; Zouiten, Cyril; Oliva, Priscia; Audry, Stéphane; Serça, Dominique

    2013-04-01

    There is a rising concern over the contribution of hydroelectric reservoirs to global anthropogenic greenhouse gases (GHGs) emissions. We present here the first comprehensive assessment of GHGs footprint associated with the creation of the Nam Theun 2 (NT2) hydroelectric reservoir in subtropical region of the Lao People's Democratic Republic. This assessment is the results of a monthly monitoring that have been conducted over 4 year (2008-to date). The carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) sources and sinks were quantified before and after impoundment, which began in May 2008. Before impoundment, the landscape to be flooded was a sink of carbon dioxide (-73 ± 225 Gg CO2eq yr-1),roughly neutral in terms of methane (7 ± 11 Gg CO2eq yr-1), and a source of nitrous oxide (345 ± 158 Gg CO2eq yr-1). After impoundment, total CO2 and CH4 emissions increased and N2O emissions decreased. For the year 2010, CO2 (791 ± 54 Gg CO2eq yr-1) and CH4 (644 ± 124 Gg CO2eq yr-1) contributed equally to the total gross GHG emissions from NT2 (54 and 43% for CO2 and CH4, respectively) whereas N2O contributed only 3% (47 ± 29 Gg CO2eq yr-1). The GHG emissions remained constant in 2011. Our results indicate that most of the GHG (around 90%) were emitted from reservoir water surface and the drawdown area, and only 10% were emitted by degassing at the turbines and from diffusive emissions downstream of the turbines and the dam, a percentage lower than reported for other hydroelectric reservoirs. With a total emissions of 1482 ± 207 and 1298 ± 200 Gg CO2eq yr-1 for year 2010 and 2011, gross NT2 emissions are about an order of magnitude higher than pre-impoundment emissions (276 ± 393 Gg CO2eq yr-1). With a net GHG emissions of 1203 ± 601 (2010) and 1022 ± 594 (2011) Gg CO2eq yr-1, and an annual power generation of about 6 TWh, GHG emission factor equal to 0.20 (2010) and 0.17 (2011) Mg CO2eq MWh-1 for NT2 which is up to five times lower than the emission factor of a thermal power plant (ranging from 0.44 to 1.05 Mg CO2eq MWh-1). Since emissions are supposed to decrease with the age of the reservoir, 2010 emission factor probably corresponds to the maximum value that would be reached for this reservoir. Work is in progress to predict the trends of GHG emissions over the projected life span (e.g. 100 years) of the reservoir. Integration of net GHG emissions at this time scale will allow a better comparison of emission factor of hydropower generation with other alternate energy sources. Keywords: Net GHG emissions, subtropical hydroelectric reservoir, Nam Theun 2

  12. Mise au point de pains composites à base de melanges de farines de sorgho-ble et analyse texturale

    Directory of Open Access Journals (Sweden)

    Blecker C.

    1999-01-01

    Full Text Available Composite breads based on sorghum-wheat flour blends and textural analysis. Breadmaking properties of flour blends containing various levels of sorghum flour with wheat flour were investigated. Good quality bread (loaf volume, crumb structure, external appearance comparable to bread entirely made from wheat flour could be produced with a level of incorporation of sorghum flour up to 30/. Beyond this level, the loaf volume decreases and the internal characteristics of crumb are deteriorated. The staling of bread made with composite flour is also influenced by the level of substitution of sorghum flour: the more important this level, the higher the rate of crumb firming. Addition of 0.5/ emulsiflers, DATEM and SSL, to the sorghum flour blends improves the crumb characteristics and consequently delays the bread firmness.

  13. Redução da emissão de CO2, CH4 e H2S através da compostagem de dejetos suínos Reduction emissions of CO2, CH4 and H2S through composting of swine manure

    Directory of Open Access Journals (Sweden)

    Luana G. Sardá

    2010-09-01

    Full Text Available Em conjunto com o crescente desenvolvimento da tecnologia para a produção de suínos ocorreu uma forte exploração e degradação do ambiente, razão pela qual a atividade se transformou em fonte poluidora das regiões produtoras. Buscam-se, então, alternativas que minimizem o potencial poluidor do atual sistema de produção. O trabalho proposto foi comparar o perfil de emissão de dióxido de carbono (CO2, metano (CH4 e gás sulfídrico (H2S do manejo de dejetos suínos nas formas sólida (compostagem e líquida (esterqueira, e avaliar a eficiência do processo de compostagem através dos parâmetros físico-químicos. O ensaio foi implantado no campo experimental da EMBRAPA Suínos e Aves, localizada no município de Concórdia, SC. Contatou-se, na compostagem, uma redução de 7 vezes na emissão de CH4, com relação à esterqueira; a emissão de CO2 representou 78,5% do carbono total mineralizado. Considerando-se que a emissão de H2S foi expressiva apenas no manejo dos dejetos na forma líquida, pode-se afirmar que o manejo dos resíduos na forma sólida é uma alternativa para a redução dos impactos ambientais pela mitigação do efeito estufa e pela redução de odores.In conjunction with the development of technologies for the production of swine meat, a strong exploration and degradation of the environment occurred and the activity became a source of pollution in the producing regions. Therefore, there is a need for alternative technologies that minimize the pollutant potential of the current system of production. The proposed work was to analyze and to compare the emission of carbon dioxide (CO2, methane (CH4 and hydrogen sulfide (H2S between the management of swine manure in solid form (composting and liquid manure (deep pit, and assess the efficiency of the process of composting through the physical and chemical parameters. The test was implemented in the experimental field of Embrapa Suínos e Aves, located in Concordia (SC. The results have showed that composting reduces 7 times the CH4 emission comparing to deep pit, and emission of CO2 represented 78.5% of total mineralized carbon. Considering that the emission of H2S was significant only in the management of waste in liquid form, then management of waste in solid form can reduce the environmental impacts, which tends to be beneficial in terms of mitigation of greenhouse effect and may contribute to the reduction of odors.

  14. Petrology and structure of greenstone blocks encased in mud-matrix melange of the Franciscan complex near San Simeon, California

    Energy Technology Data Exchange (ETDEWEB)

    Davidsen, R.K.; Cloos, M.

    1985-01-01

    Greenstones comprise about 20% of all mappable (>1 m) blocks encased in blueschist-block-bearing mud-matrix melange exposed in a 10 km-length of sea cliffs near San Simeon. Field and petrographic analysis of 25 blocks show they vary from finely crystalline (<1 mm) locally porphyritic or amygdaloidal, volcanics to coarsely crystalline (1 to 5 mm) diabase. Some are in contact with bedded chert and two have relict pillows. However, most blocks are intensely deformed. Pinch-and-swell and boundinage are recognized on scales from cm to about 10 m. Distortion was accommodated by cataclasis to an aggregate of pieces from mm to m across. Generally, m-sized blocks are pervasively cataclastic whereas larger blocks are crosscut by cataclastic zones that emanate from pervasively cataclastic margins or necked regions of boudins. Discontinuous, cm-thick veins and cavities that are lined by quartz and clacite and rarely, laumontite, prehnite and aragonite locally crosscut all other structures. Relict igneous textures show the primary minerals are plagioclase and clinopyroxene. Abundant secondary minerals, particularly in cataclastic zones, are albite, chlorite, pumpellyite (some have high Al), and calcite. The metamorphic parageneses indicate relatively minor greenschist-facies, sea-floor-type alterations under static conditions followed by lower-temperature alterations synchronous with cataclasis and the development of boudinage. If the blocks are fragments of disrupted ophiolites, only the uppermost section of the suite are present within the mud-matrix melange near San Simeon. The simplest explanation for their crystallization, metamorphism and incorporation into the melange is that they are fragments of seamounts dismembered during subduction.

  15. TECTONIC POSITION OF MARBLE MELANGES IN THE EARLY PALEOZOIC ACCRETION-COLLISIONAL SYSTEM OF THE WESTERN PRIBAIKALIE

    Directory of Open Access Journals (Sweden)

    V. S. Fedorovsky

    2015-09-01

    Full Text Available The Early Paleozoic collisional system located in the Olkhon region at the western shores of Lake Baikal resulted from collision of the Siberian paleocontinent and a complex aggregate composed by fragments of a microcontinent, island arcs, back-arc structures and accretionary prisms. The main events were associated with complete manifestation of shear tectogenesis initiated by oblique collision. The current structure includes tectonically displaced components of ancient geodynamic systems that used to have been located dozens and hundreds of kilometres apart. Horizontal amplitudes of tectonic displacement seem to have been quite high; however, numerical data are still lacking to support this conclusion. Information about the structure of the upper crust in the Paleozoic is also lacking as only deep metamorphic rocks (varying from epidote-amphibolite to granulite facies are currently outcropped. Formations comprising the collisional collage are significantly different in composition and protoliths, and combinations of numerous shifted beds give evidence of a 'bulldozer' effect caused by the collisional shock followed by movements of crushed components of the ocean-continent zone along the margin of the Siberian paleocontinent. As evidenced by the recent cross-section, deep horizons of the Early Paleozoic crust comprise the collisional system between the Siberian craton and the Olkhon composite terrain. A permanent inclusion in the collisional combinations of rocks are unusual synmetamorphic injected bodies of carbonate rocks. Such rocks comprise two groups, marble melanges and crustal carbonate melted rocks. Obviously, carbonate rocks (that composed the original layers and horizons of stratified beds can become less viscous to a certain degree at some locations during the process of oblique collision and acquire unusual properties and can thus intrude into the surrounding rocks of silicate composition. Such carbonate rocks behave as protrusions

  16. The P-T-t history of blocks in serpentinite-matrix melange, west-central Baja California

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, S.L.; Harrison, T.M. [State Univ. of New York, Albany, NY (United States)

    1992-01-01

    Thermochronologic, petrologic, and geochemical analyses of epidote-amphibolite-, amphilbolite-, eclogite-, and blueschist-facies blocks in serpentinite-matrix melanges from East San Benito Island and Cedros Island, west-central Baja California, provide constraints on the P-T-t history of this disrupted terrane. Results of {sup 40}Ar/{sup 39}Ar step heating experiments on minerals separated from these blocks vary according to metamorphic grade and indicate different P-T-t histories. Mid-Jurassic (160-170 Ma) epidote-amphibolite- and amphibolite-facies blocks were probably derived from oceanic crust and associated sediments that were metamorphosed during limitation of subduction. Coarse-grained blueschist blocks were likely metamorphosed during continued subduction in late Early Cretaceous time (that is, 115-100 Ma). Some epidote-amphibolite blocks are partially overprinted by blueschist-facies mineral assemblages and apparently record both metamorphic events. Fission-track analyses of apatites indicate that the blocks underwent significantly different post-metamorphic cooling histories. Epidote-amphilbolite and amphibolite blocks cooled below {approximately}100 {degrees}C form mid-Jurassic to Paleocene time; blueschist blocks cooled below {approximately}100 {degrees}C in Oligocene-Miocene time. In general, mafic blocks have trace-element concentrations and REE patterns characteristic of ocean-flood basalts. This study demonstrates that samples with very different P-T-t histories can evidently occur over relatively small length scales (<<1 km) in serpentinite-matrix melanges. 67 refs., 16 figs., 4 tabs.

  17. Middle Jurassic Radiolaria from a siliceous argillite block in a structural melange zone near Viqueque, Timor Leste: Paleogeographic implications

    Science.gov (United States)

    Haig, David W.; Bandini, Alexandre Nicolas

    2013-10-01

    Thin-bedded siliceous argillite forming a large block within a structural melange zone at Viqueque, Timor Leste, has yielded a Middle Jurassic (late Bathonian-early Callovian) radiolarian assemblage belonging to Unitary Association Zone 7. Fifty-five species are recognized and illustrated, forming the most diverse radiolarian fauna yet documented from the Jurassic of Timor. The fauna shows little similarity in species content to the few other assemblages previously listed from the Middle or Late Jurassic of Timor, and also has few species in common with faunas known elsewhere in the region from Rotti, Sumatra, South Kalimantan, and Sula. Based on lithofacies similarities and age, the siliceous argillite succession in the melange block at Viqueque is included in the Noni Group originally described as the lower part of the Palelo Series in West Timor. In terms of lithofacies, the Noni Group is distinct from other stratigraphic units known in Timor. It may be associated with volcanic rocks but age relationships are uncertain, although some of the radiolarian cherts in the Noni Group in West Timor have been reported to include tuffaceous sediment. The deep-water character of the siliceous hemipelagite-pelagite facies, the probable volcanic association, and an age close to that of continental breakup in the region suggest deposition in a newly rifted Indian Ocean. In Timor's tectonostratigraphic classification scheme, the Noni Group is here placed in the "Indian Ocean Megasequence".

  18. Application of radiolarians and other fossils in non-Smith strata——Exemplified by the A’nyemaqen melange belt in East Kunlun Mts.

    Institute of Scientific and Technical Information of China (English)

    张克信; 黄继春; 殷鸿福; 王国灿; 王永标; 冯庆来; 田军

    2000-01-01

    The main character of melange strata in an erogenic belt is the integration of mixed materials due to the superposition, displacement or loss of various tectonic slices (blocks) of different origins and environments, different scales, different grades of deformation and metamor-phism, and different stages of tectonic evolution. The approach to non-Smith strata in an erogenic belt is to focus on the understanding of the age, facies, tectonic setting of the original formation and the process of deformation-metamorphism of each tectonic slice, reconstruct the history of dispersal and integration of these tectonic slices in time and space, i.e. 4-dimensional. This paper studies the age and facies of the original formation of tectonic slices in the A’nyemaqen melange belt based on new data of radiolarians, sporo-pollen and trace fossils, and cast new lights on the research of the evolution process of that belt.

  19. Seasonal changes of CO2, CH4 and N2O fluxes in relation to land-use change in tropical peatlands located in coastal area of South Kalimantan

    International Nuclear Information System (INIS)

    Tropical peatland could be a source of greenhouse gases emission because it contains large amounts of soil carbon and nitrogen. However these emissions are strongly influenced by soil moisture conditions. Tropical climate is characterized typically by wet and dry seasons. Seasonal changes in the emission of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) were investigated over a year at three sites (secondary forest, paddy field and upland field) in the tropical peatland in South Kalimantan, Indonesia. The amount of these gases emitted from the fields varied widely according to the seasonal pattern of precipitation, especially methane emission rates were positively correlated with precipitation. Converting from secondary forest peatland to paddy field tended to increase annual emissions of CO2 and CH4 to the atmosphere (from 1.2 to 1.5 kg CO2-C m-2 y-1 and from 1.2 to 1.9 g CH4-C m-2 y-1), while changing land-use from secondary forest to upland tended to decrease these gases emissions (from 1.2 to 1.0 kg CO2-C m-2 y-1 and from 1.2 to 0.6 g CH4-C m-2 y-1), but no clear trend was observed for N2O which kept negative value as annual rates at three sites. (Author)

  20. Evaluation of the greenhouse effect gases (CO2, CH4, N2O) in grass land and in the grass breeding. Greenhouse effect gases prairies. report of the first part of the project December 2002

    International Nuclear Information System (INIS)

    In the framework of the Kyoto protocol on the greenhouse effect gases reduction, many ecosystems as the prairies can play a main role for the carbon sequestration in soils. The conservation of french prairies and their management adaptation could allow the possibility of carbon sequestration in the soils but also could generate emissions of CO2 and CH4 (by the breeding animals on grass) and N2O (by the soils). This project aims to establish a detailed evaluation of the contribution of the french prairies to the the greenhouse effect gases flux and evaluate the possibilities of reduction of the emissions by adaptation of breeding systems. (A.L.B.)

  1. "Atmospheric Measurements by Ultra-Light SpEctrometer" (AMULSE) dedicated to vertical profile measurements of greenhouse gases (CO2, CH4) under stratospheric balloons: instrumental development and field application.

    Science.gov (United States)

    Maamary, Rabih; Joly, Lilian; Decarpenterie, Thomas; Cousin, Julien; Dumelié, Nicolas; Grouiez, Bruno; Albora, Grégory; Chauvin, Nicolas; Miftah-El-Khair, Zineb; Legain, Dominique; Tzanos, Diane; Barrié, Joel; Moulin, Eric; Ramonet, Michel; Bréon, François-Marie; Durry, Georges

    2016-04-01

    Human activities disrupt natural biogeochemical cycles such as the carbon and contribute to an increase in the concentrations of the greenhouse gases (carbone dioxide and methane) in the atmosphere. The current atmospheric transport modeling (the vertical trade) still represents an important source of uncertainty in the determination of regional flows of greenhouse gases, which means that a good knowledge of the vertical distribution of CO2 is necessary to (1) make the link between the ground measurements and spatial measurements that consider an integrated concentration over the entire column of the atmosphere, (2) validate and if possible improve CO2 transport model to make the link between surface emissions and observed concentration. The aim of this work is to develop a lightweight instrument (based on mid-infrared laser spectrometry principles) for in-situ measuring at high temporal/spatial resolution (5 Hz) the vertical profiles of the CO2 and the CH4 using balloons (meteorological and BSO at high precision levels (logistics flights. These laser spectrometers are built on recent instrumental developments. Several flights were successfully done in the region Champagne-Ardenne and in Canada recently. Aknowledgments: The authors acknowledge financial supports from CNES, CNRS défi instrumental and the region Champagne-Ardenne.

  2. ÉMISSION DE GAZ A EFFET DE SERRE (CO2, CH4) PAR UNE RETENUE DE BARRAGE HYDROÉLECTRIQUE EN ZONE TROPICALE (PETIT-SAUT, GUYANE FRANÇAISE) :
    EXPÉRIMENTATION ET MODÉLISATION

    OpenAIRE

    Guérin, Frédéric

    2006-01-01

    The emissions of carbon dioxide (CO2) and methane (CH4) and the carbon cycle in the Petit-Saut reservoir and in the Sinnamary River (French Guiana) were studied with an aim of developing a coupled physical/biogeochemical model. The development of this model required the study of three processes controlling these emissions: (i) CO2 and CH4 production during the mineralization in anoxic condition of organic matter (OM) from soils and plants, (ii) aerobic CH4 oxidation in the water column of the...

  3. Long-term measurements of atmospheric trace gases (CO2, CH4, N2O, SF6, CO, H2), O2, and δ13CH4 isotopes at Weybourne Atmospheric Observatory, UK: past, present and future

    Science.gov (United States)

    Manning, Andrew C.; Forster, Grant L.; Oram, David E.; Reeves, Claire E.; Pickers, Penelope A.; Barningham, S. Thomas; Sturges, William T.; Bandy, Brian; Nisbet, Euan G.; Lowry, David; Fisher, Rebecca; Fleming, Zoe

    2016-04-01

    The Weybourne Atmospheric Observatory (WAO) is situated on the north Norfolk Coast (52.95°N, 1.13°E) in the United Kingdom and is run by the University of East Anglia (UEA), with support from the UK National Centre for Atmospheric Science (NCAS). In 2016, the WAO became a UK-ICOS (Integrated Carbon Observing System) monitoring station. Since 2008, we have been collecting high-precision long-term in situ measurements of atmospheric carbon dioxide (CO2), oxygen (O2), carbon monoxide (CO) and molecular hydrogen (H2), as well as regular bag sampling for δ13CH4. In early 2013, the measurement of atmospheric methane (CH4) commenced, and nitrous oxide (N2O) and sulphur hexafluoride (SF6) began in 2014. We summarise the CO2, O2, CH4, N2O, SF6, CO, H2 and δ13CH4 measurements made to date and highlight some key features observed (e.g. seasonal cycles, long-term trends, pollution events and deposition events). We summarise how the long-term measurements fit into other broader projects which have helped to support the long term time-series at WAO over the years, and highlight how we contribute to broader global atmospheric observation networks.

  4. How well can we assess impacts of agricultural land management changes on the total greenhouse gas balance (CO2, CH4 and N2O) of tropical rice-cropping systems with biogeochemical models?

    Science.gov (United States)

    Kraus, David; Weller, Sebastian; Janz, Baldur; Klatt, Steffen; Santabárbara, Ignacio; Haas, Edwin; Werner, Christian; Wassmann, Reiner; Kiese, Ralf; Butterbach-Bahl, Klaus

    2016-04-01

    Paddy rice cultivation is increasingly challenged by physical and economic irrigation water scarcity. This already results in the trend of converting paddy rice to upland crop cultivation (e.g., maize, aerobic rice) in large parts of South East Asia. Such land management change from flooded lowland systems to well-aerated upland systems drastically affects soil C and N cycling and related emissions of greenhouse gases. Emissions of methane (CH4) are expected to decrease, while emissions of nitrous oxide (N2O) will most likely increase. In addition to such fast evolving 'pollution swapping' it is expected that on longer time scales significant amounts of soil organic carbon (SOC) stocks will be lost in form of carbon dioxide (CO2). Within the DFG-funded research unit ICON (Introducing non-flooded crops in rice-dominated landscapes: Impact on carbon, nitrogen and water cycles), we investigated environmental impacts of land management change from historical paddy rice cultivation to the upland crops maize and aerobic rice at experimental sites at the International Rice Research Institute (IRRI), the Philippines. To present, more than three years of continuous measurement data of CH4 and N2O emissions under different fertilization regimes have been collected. In addition, measurements of SOC contents and bulk densities in different soil horizons allow for an overall very good characterization of the environmental impacts of mentioned land management change. In this contribution we will show how well mentioned land management change effects in tropical agricultural systems can be represented and thus better understood by the help of process-based biogeochemical models. Seasonal emissions of CH4 and N2O are simulated with r2 values of 0.85 and 0.78 and average underestimations of 15 and 14 %, respectively. These underestimations predominantly originate from treatments in which no fertilizer is applied (CH4) as well as uncertainties of soil hydrology (N2O). Long-term development of SOC stocks is highly influenced by the soil oxygen status as well as the growth of photosynthetic active aquatic biomass. Moreover, simulation results demonstrate that short-term GHG balances may considerably differ from long-term balances. Simulated total GHG emissions 2.5 years after land management change are highest for upland crop - paddy rice rotations due to pronounced losses of soil organic carbon. In contrast, over a longer period of several decades total GHG emissions are highest for double cropping of paddy rice clearly dominated by CH4 emissions. Simulation results suggest that approx. 2.8 - 3.4 t C ha‑1 yr‑1 residue incorporation after harvest is needed in order to sustain stable SOC stocks in mixed upland crop - paddy rice systems.

  5. High-pressure studies to determine the effects of volume and temperature on the lattice dynamics of molecular solids: N2, CO2, CH4. Final report for period July 1, 1979-August 31, 1981

    International Nuclear Information System (INIS)

    The main goal of the project was to carry out spectroscopic studies at different pressures and temperatures to provide additional information on the intermolecular potentials of simple molecular solids. A new high pressure infrared was specifically designed for the project. ir studies in α-N2 resulted in positive anharmonic self-energy shifts and a Grueneisen parameter of 3. Preliminary analysis of similar studies of solid methane indicate little anharmonicity in phase III and a transition to a phase IV which might explain a previously observed dielectric anomaly. Raman studies in solid CH4 indicate an anisotropic intermolecular potential with a strong volume dependence, again little anharmonicity, and a III-IV phase transition which involves the reorientation of some molecules. In fluids, the density dependence on intramolecular frequencies has a striking resemblance to the intermolecular potential and molecular dynamics calculations of the effect are yet to be completed. Cous oxide was also investigated. The reaction is first order in nitrite ion, second order in hydrogen ion, and between zero and first order in hydroxylamine monosulfonate, depending on the concentration

  6. High-pressure studies to determine the effects of volume and temperature on the lattice dynamics of molecular solids: N2, CO2, CH4. Progress report, July 1, 1980-June 30, 1981

    International Nuclear Information System (INIS)

    Studies summarized in this report on research programs at Northeastern University include: far infrared absorption spectroscopy of solid nitrogen; a study of volume and temperature dependence of the Raman soectrum in phase II of solid methane; the collision-induced light scattering spectrum of fluid methane; the light scattering spectrum of fluid nitrogen at 1570K and densities between 128 and 462 amagat; growth of β-N2 at pressures of 2.7 and 4.6 Kbar on the melting line and cooling to the alpha phase; measurement of the breathing mode frequency of the methane molecule at 2400K up to density of 800 amagat; and growth of samples of solid methane

  7. "Atmospheric Measurements by Ultra-Light SpEctrometer" (AMULSE) dedicated to vertical profile measurements of greenhouse gases (CO2, CH4) under stratospheric balloons: instrumental development and field application.

    Science.gov (United States)

    Maamary, Rabih; Joly, Lilian; Decarpenterie, Thomas; Cousin, Julien; Dumelié, Nicolas; Grouiez, Bruno; Albora, Grégory; Chauvin, Nicolas; Miftah-El-Khair, Zineb; Legain, Dominique; Tzanos, Diane; Barrié, Joel; Moulin, Eric; Ramonet, Michel; Bréon, François-Marie; Durry, Georges

    2016-04-01

    Human activities disrupt natural biogeochemical cycles such as the carbon and contribute to an increase in the concentrations of the greenhouse gases (carbone dioxide and methane) in the atmosphere. The current atmospheric transport modeling (the vertical trade) still represents an important source of uncertainty in the determination of regional flows of greenhouse gases, which means that a good knowledge of the vertical distribution of CO2 is necessary to (1) make the link between the ground measurements and spatial measurements that consider an integrated concentration over the entire column of the atmosphere, (2) validate and if possible improve CO2 transport model to make the link between surface emissions and observed concentration. The aim of this work is to develop a lightweight instrument (based on mid-infrared laser spectrometry principles) for in-situ measuring at high temporal/spatial resolution (5 Hz) the vertical profiles of the CO2 and the CH4 using balloons (meteorological and BSO at high precision levels (authorizations, costs and logistics flights. These laser spectrometers are built on recent instrumental developments. Several flights were successfully done in the region Champagne-Ardenne and in Canada recently. Aknowledgments: The authors acknowledge financial supports from CNES, CNRS défi instrumental and the region Champagne-Ardenne.

  8. Gridino melange zone of the Belomorian eclogite province: Succession of tectonic events and structural position of mafic dyke swarms

    Science.gov (United States)

    Babarina, I. I.; Sibelev, O. S.; Stepanova, A. V.

    2014-07-01

    Based on relationships between Paleoproterozoic mafic dykes, lithotectonic complexes, and tectonic structures of the Gridino Zone in the Belomorian eclogite province of the Fennoscandian Shield, deformations have been divided into groups differing in age and the succession of tectonic events has been reconstructed. The formation of Neoarchean eclogite-bearing melange was related to disintegration of large eclogite sheets in the course of near-horizontal ductile flow accompanied by syntectonic granitoid magmatism, multiple migmatization, and granulite-to amphibolite-facies metamorphism. The exotic blocks, including eclogites, were incorporated into TTG gneisses as sheets and lenses up to a few hundreds of meters in thickness and oriented conformably with gneissic banding. As a result of ductile flow, the lithotectonic complexes were transported at the level of discrete brittle-ductile deformations expressed as strike-slip faults and associated folds. Under conditions of a relatively rigid medium, individual structural elements underwent rotation approximately through 90° in plan view. Under the extension regime in the Early Paleoproterozoic, several swarms of mafic dykes were injected into the already cold framework rocks, as is evident from dyke morphology. The dykes crosscut all predated structures, included turned blocks, and are therefore important reference points for subdivision of Neoarchean and Paleoproterozoic processes. The Svecofennian postdyke tectonic activity was accompanied by local shearing and boudinage of metabasic rocks, development of quartz and pegmatite veins along tension cracks, disharmonic folding, and discrete retrograde metamorphism up to amphibolite-facies conditions. The postdyke deformations did not exert a substantial effect on the previously formed regional structure.

  9. Blueschist Blocks in the Shale-matrix Melange of the Franciscan Complex of California: Metamorphic Aureoles and Subduction Channel Upwelling

    Science.gov (United States)

    Cloos, Mark; Ukar, Estibalitz

    2014-05-01

    The subduction channel concept postulates that where oceanic lithosphere converges faster than ~2 cm/yr, the plate boundary is best approximated as a viscous shear zone. Channel capacity can abruptly decrease where there is a sharp increase in the pressure gradient along the top of the shear zone. Where this occurs, subducted sediment can upwell and flow back towards the inlet. The Central Belt of the Franciscan Complex is up to tens of km wide and extends from where subduction continues in Oregon southwards to the Nacimiento Block, west of the San Andreas fault. The scaly shale matrix outcrops poorly along the 1500+ km belt because it is weakly metamorphosed (blueschists (e.g., Tiburon, Jenner Beach). How these high-T blocks, the oldest metamorphics in the Franciscan and the more voluminous lower-T blueschists became rounded fragments encased in shale-matrix has been the subject of much discussion. Uplift in serpentine diapirs is widely invoked, but the scarcity of these blocks in serpentinite where exposures are good is problematic. Explaining the blocks as sedimentary olistoliths requires both a phantom source terrane and exhumation mechanism. The simplest explanation is that the coarse blueschists are fragments of a metamorphic aureole formed during subduction initiation that were later detached from the base of the ophiolitic leading edge of the North American plate. Later, tectonic melange was generated by subduction-driven shearing that caused upwelling of shale-rich sediment. Slabs of blueschist were boudinaged and mixed with fragments of greenstone and chert detached from seamounts. Blueschist block incorporation into upwelling mélange is a kind of subduction erosion akin to plucking by glaciers. The exposure of the blueschist along the roof of the subduction channel may have been mostly localized to near where normal faults formed in the overriding block as Farallon plate dip flattened from 80 to 40 Ma. Only blocks of the appropriate size and density can

  10. The Mt. Ochi melange (South Evvia Island, Greece): a case study for HP metamorphism and syn-convergent exhumation.

    Science.gov (United States)

    Moustaka, Eleni; Soukis, Konstantinos; Huet, Benjamin; Lozios, Stylianos; Magganas, Andreas

    2014-05-01

    by the mineral assemblage Na-amphibole + lawsonite seen as inclusion in epidote porphyroblasts within the melange. It could represent a structure of the prograde path but it could also have formed during the peak HP event. This is followed by successive folding episodes that are related to axial plane foliations and a ~E-W intersection/stretching lineation formed by typical blueschist- to epidote-blueschist facies mineral assemblages. The main foliation that can be observed in all three units is a greenschist-facies axial plane foliation accompanied by a ~ENE-WSW stretching lineation. The shear sense during the prograde path is constantly towards the WSW. In the greenschists-facies an unambiguous top-to ENE can be observed mostly in mylonitic rocks. The following deformation episodes include semi-brittle to brittle structures (shear bands brittle open folds, crenulation cleavage, and faults with increasingly higher-angle) that are not as penetrative and record the passage of the units through the brittle-ductile transitions and to higher structural levels. The kinematics of these late episodes is also towards the NE. Based on the above, the Mt Ochi HP units exhibit a common tectonometamorphic evolution since at least the early stages of the prograde path. The Ochi Unit/Styra Unit contact is a structure that formed prior to or during peak HP metamorphism and therefore it couldn't have served as the normal fault to an extrusion wedge.

  11. Time evolution of relativistic d + Au and Au + Au collisions

    CERN Document Server

    Wolschin, G; Mizoguchi, T; Suzuki, N; Biyajima, Minoru; Mizoguchi, Takuya; Suzuki, Naomichi; Wolschin, Georg

    2006-01-01

    The evolution of charged-particle production in collisions of heavy ions at relativistic energies is investigated as function of centrality in a nonequilibrium-statistical framework. Precise agreement with recent d + Au and Au + Au data at sqrt(s_NN) = 200 GeV is found in a Relativistic Diffusion Model with three sources for particle production. Only the midrapidity source comes very close to local equilibrium, whereas the analyses of the overall pseudorapidity distributions show that the systems remain far from statistical equilibrium.

  12. Strongly foliated garnetiferous amphibolite clasts in ophiolitic melanges, Yarlung Zangbo Suture Zone, Tibet; Early Cretaceous disruption of a back-arc basin?

    Science.gov (United States)

    Guilmette, C.; Hebert, R.; Wang, C.; Indares, A. D.; Ullrich, T. D.; Dostal, J.; Bedard, E.

    2007-12-01

    Metre to decameter-size clasts of amphibolite are found embedded in ophiolitic melanges underlying the Yarlung Zangbo Suture Zone Ophiolites, South Tibet, China. These ophiolites and melanges occur at the limit between Indian and Tibetan-derived rocks and represent remnants of an Early Cretaceous intraoceanic supra-subduction zone domain, the Neo-Tethys. In the Saga-Dazuka segment (500 km along-strike), we discovered new occurrences of strongly foliated amphibolites found as clasts in the ophiolitic melange. In garnet-free samples, hornblende is green-blue magnesio-hornblende and cpx is low-Al diopside. In garnet- bearing samples, garnet is almandine with a strong pyrope component (up to 30 mol%) whereas coexisting hornblende is brown Ti-rich tschermakite and clinopyroxene is Al-diopside. Plagioclase composition was ubiquitously shifted to albite during a late metasomatic event. Geochemistry of these rocks indicates that their igneous protoliths crystallized from a slightly differentiated tholeiitic basaltic liquid that did not undergo major fractionation. Trace element patterns reveal geochemical characteristics identical to those of the overlying ophiolitic crust. These are 1) trace element abundances similar to that of N-MORBs or BABBs, 2) a slight depletion of LREE and 3) a moderate to strong Ta-Nb negative anomaly and a slight Ti anomaly. Such characteristics suggest genesis over a spreading center close to a subduction zone, possibly a back-arc basin. Step-heating Ar/Ar plateau ages were obtained from hornblende separates. All ages fall in the range of 123-128 Ma, overlapping the crystallization ages from the overlying ophiolite (126-131 Ma). Pseudosections were built with the THERMOCALC software in the system NCFMASH. Results indicate that the observed assemblage Hb+Pl+Gt+Cpx is stable over a wide range of P-T conditions, between 10-18 kbars and at more than 800°C. Measured mineral modes and solid solution compositions were successfully modeled, indicating

  13. Broken formations, melanges and olistostromes in Puerto Plata area (Northern Dominican Republic) as a record of subduction and collisional processes between the Caribbean and North-American plates

    Science.gov (United States)

    Hernaiz Huerta, Pedro Pablo; Valera Fernando, Pérez; de Los Santos Manuel, Abad; Jacques, Monthel; de Neira Alberto, Díaz

    2010-05-01

    The Northern Cordillera of the Dominican Republic records the (oblique) subduction and collisional processes occurred between the Caribbean and North-American plates during Upper Cretaceous to Lower Paleogene times. The boundary between these two plates can be traced within this range disrupted by an Upper Paleogene to present intense left-lateral strike-slip tectonism, onset after collision. In the western part of the range this boundary might be defined by the Camu fault. In the coastal area of Puerto Plata, located on the northern block of the Camu fault, basement rocks belonging to the subducting plate (the Puerto Plata Basement Complex) and several related units probably formed in an accretionary prism, preserve in a large (300 km2) outcrop of chaotic formations presumably formed (and exhumed) during collision. They include from broken formations and tectonic melanges to olistostromes and other coeval sedimentary deposits. The Puerto Plata Basement Complex (PPBC) consists of highly faulted and dismembered blocks formed by discontinuous but sometimes coherent outcrops of serpentinized or massive peridotite, pods of ultramafic cumulates, massive or banded gabbros and Los Caños Fm, a thick sequence of gross bedded volcaniclastic material with interbedded basaltic (sometimes pillowed) or andesitic flows. All these rocks bear low grade metamorphism and lack a general deformation fabric apart from occasional transformation to mylonites due to localized shearing. The PPBC has been interpreted as a fragment of oceanic crust, belonging to the subducting (North-American) slab that has been exhumed as a tectonic melange or a broken complex. The Imbert Fm, of Palaeocene-Eocene age, is formed by a well bedded succession of white very fine grained porcelaneous tuffs, with eventual intercalations of cherts, limestones and marls that, towards the lower part, is interbedded with volcanic-derived graywackes and limolites, and more occasionally, thick beds of conglomerates and

  14. Ultra-relativistic Au+Au and d+Au collisions:

    Science.gov (United States)

    Back, B. 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.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Hauer, M.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; 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.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Seals, H.; Sedykh, I.; Skulski, W.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    In this talk I will review PHOBOS data on charged particle multiplicities, obtained in Au+Au and d+Au collisions at RHIC. The general features of the Au+Au pseudorapidity distributions results will be discussed and compared to those of /line{p}p collisions. The total charged particle multiplicity, scaled by the number of participant pairs, is observed to be about 40% higher in Au+Au collisions than in /line{p}p and d+Au systems, but, surprisingly at the same level of e+e- collisions. Limiting fragmentation scaling is seen to be obeyed in Au+Au collisions.

  15. Collective flow in Au + Au collisions

    International Nuclear Information System (INIS)

    Based on a preliminary sample of Au + Au collisions in the EOS time projection chamber at the Bevalac, we study sideward flow as a function of bombarding energy between 0.25A GeV and 1.2A GeV. We focus on the increase in in-plane transverse momentum per nucleon with fragment mass. We also find event shapes to be close to spherical in the most central collisions, independent of bombarding energy and fragment mass up to 4He

  16. Denmark's national inventory report. Submitted under the United Nations framework convention on climate change, 1990-2001. Emission inventories

    International Nuclear Information System (INIS)

    This report is Denmark's National Inventory Report reported to the Conference of the Parties under the United Nations Framework Convention on Climate Change (UNFCCC) due bye 15 April 2003. The report contains information on Denmark's inventories for all years' from 1990 to 2001 for CO2, CH4, N2O, CO, NMVOC, SO2, HFCs, PFCs and SF6. (au)

  17. Denmark's national inventory report 2006 - Submitted under the United Nations framework convention on climate change, 1990-2004. Emission inventories

    International Nuclear Information System (INIS)

    This report is Denmark's National Inventory Report reported to the Conference of the Parties under the United Nations Framework Convention on Climate Change (UNFCCC) due by 15 April 2006. The report contains information on Denmark's inventories for all years' from 1990 to 2004 for CO2, CH4, N2O, HFCs, PFCs and SF6, CO, NMVOC, SO2. (au)

  18. Denmark's National Inventory Reports. Submitted under the United Nations framework convention on climate change

    International Nuclear Information System (INIS)

    This report is Denmark's National Inventory Report reported to the Conference of the Parties under the United Nations Framework Convention on Climate Change (UNFCCC) due by 15 April 2000. The report contains information on Denmark's inventories for all years from 1990 to 1998 for CO2, CH4, N2O, NOx, CO, NMVOC, SO2, HFCs, PFCs and SF. (au)

  19. Au pair trajectories

    DEFF Research Database (Denmark)

    Dalgas, Karina Märcher

    2015-01-01

    workers from the global South, the first article demonstrates how Facebook can be a fruitful methodological tool in the aspiration to open up the research to new themes of inquiry. However, rather than disregarding the au pairs’ economic problems, the dissertation shows how their family participation and......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...... pair-sending families in the Philippines, this dissertation examines the long-term trajectories of these young Filipinas. It shows how the au pairs’ local and transnational family relations develop over time and greatly influence their life trajectories. A focal point of the study is how au pairs...

  20. Analysis of hydrogen-deuterium mixtures and of mixtures of heavy-water and light-water by means of a mass spectrometer; Analyse des melanges hydrogene-deuterium et des melanges d'eau lourde et d'eau legere au moyen du spectrometre de masse

    Energy Technology Data Exchange (ETDEWEB)

    Chenouard, J.; Gueron, J.; Roth, E

    1951-07-01

    The differences between hydrogen and deuterium with respect to the capture of thermal neutrons (hydrogen = 0.31 barn; deuterium 0.00065 barn) explains the interest of detecting small variations of the isotopic composition of the heavy waters used in the Chatillon nuclear pile. The aim of this report is to describe and discuss the method used since more than a year for the dosimetry of heavy waters. After a recall of the principle of mass spectroscopy analysis of deuterium-hydrogen mixtures, the preciseness of the results is presented and the balancing method used for the determination of the isotopic composition of hydrogen-deuterium mixtures is explained in detail. Finally, a brief comparison of the preciseness of mass spectroscopy measurements with the analyses made with other methods is performed. Some calculations and the tables of results are presented in appendixes. (J.S.)

  1. Electrodisintegration of 197Au

    International Nuclear Information System (INIS)

    Cross sections for the (e, xn) reaction on 197Au have been measured for 1= 4 were calculated by means of an intranuclear cascade model. Good agreement is found for x = 7 is discussed. No evidence is found for giant resonances in regions above the giant dipole resonance. (Auth.)

  2. 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....

  3. Magnetic susceptibilities of liquid Cr-Au, Mn-Au and Fe-Au alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, S.; Shimakura, H. [Niigata University of Pharmacy and Applied Life Sciences, Higashijima, Akiha-ku, Niigata 956-8603 (Japan); Tahara, S. [Faculty of Science, University of the Ryukyus, Nishihara-cho, Okinawa 903-0213 (Japan); Okada, T. [Niigata College of Technology, Kamishin’eicho, Nishi-ku, Niigata 950-2076 (Japan)

    2015-08-17

    The magnetic susceptibility of liquid Cr-Au, Mn-Au, Fe-Au and Cu-Au alloys was investigated as a function of temperature and composition. Liquid Cr{sub 1-c}Au{sub c} with 0.5 ≤ c and Mn{sub 1-c}Au{sub c} with 0.3≤c obeyed the Curie-Weiss law with regard to their dependence of χ on temperature. The magnetic susceptibilities of liquid Fe-Au alloys also exhibited Curie-Weiss behavior with a reasonable value for the effective number of Bohr magneton. On the Au-rich side, the composition dependence of χ for liquid TM-Au (TM=Cr, Mn, Fe) alloys increased rapidly with increasing TM content, respectively. Additionally, the composition dependences of χ for liquid Cr-Au, Mn-Au, and Fe-Au alloys had maxima at compositions of 50 at% Cr, 70 at% Mn, and 85 at% Fe, respectively. We compared the composition dependences of χ{sub 3d} due to 3d electrons for liquid binary TM-M (M=Au, Al, Si, Sb), and investigated the relationship between χ{sub 3d} and E{sub F} in liquid binary TM-M alloys at a composition of 50 at% TM.

  4. Etre touareg au Mali

    OpenAIRE

    Edmond BERNUS

    1992-01-01

    Après une présentation générale de leur espace, de leur culture commune, des stéréotypes dont ils font l'objet, les Touaregs maliens sont décrits dans leurs diversités régionales. Les révoltes passées, celle de Firhoun, le héros de 1916, puis celle de l'Adrar des Iforas en 1963-64 contre le gouvernement de Modibo Keita, précédent la révolte qui s'étend depuis 1990 au Niger et au Mali avec des guerriers sachant manier armes et voitures. Attaques et répression sauvage se succèdent dans une spir...

  5. Introduction au droit commercial

    OpenAIRE

    Thirion, Nicolas; Delvaux, Thierry; Benoit-Moury, Anne

    2009-01-01

    Le cours d'introduction au droit commercial, destiné à des non-juristes, a pour objet de décrire, dans ses grandes lignes, le régime juridique applicable à l'organisation et au fonctionnement de l'économie. Les liens avec des disciplines autres que le droit, notamment l'économie et l'histoire, seront privilégiés, afin d'adapter la matière aux besoins et centres d'intérêts d'étudiants en sciences humaines. Après une introduction générale, le cours s'articule autour de la trilogie fondamentale ...

  6. Antibacterial Au nanostructured surfaces

    Science.gov (United States)

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-01-01

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was information (ESI) available. See DOI: 10.1039/c5nr06157a

  7. Magnetic susceptibilities of liquid Cr-Au, Mn-Au and Fe-Au alloys

    International Nuclear Information System (INIS)

    The magnetic susceptibility of liquid Cr-Au, Mn-Au, Fe-Au and Cu-Au alloys was investigated as a function of temperature and composition. Liquid Cr1-cAuc with 0.5 ≤ c and Mn1-cAuc with 0.3≤c obeyed the Curie-Weiss law with regard to their dependence of χ on temperature. The magnetic susceptibilities of liquid Fe-Au alloys also exhibited Curie-Weiss behavior with a reasonable value for the effective number of Bohr magneton. On the Au-rich side, the composition dependence of χ for liquid TM-Au (TM=Cr, Mn, Fe) alloys increased rapidly with increasing TM content, respectively. Additionally, the composition dependences of χ for liquid Cr-Au, Mn-Au, and Fe-Au alloys had maxima at compositions of 50 at% Cr, 70 at% Mn, and 85 at% Fe, respectively. We compared the composition dependences of χ3d due to 3d electrons for liquid binary TM-M (M=Au, Al, Si, Sb), and investigated the relationship between χ3d and EF in liquid binary TM-M alloys at a composition of 50 at% TM

  8. Des femmes au tribunal

    OpenAIRE

    Le Pape, Marc

    2010-01-01

    Les archives judiciaires constituent une source essentielle pour les études des sociabilités africaines en situation coloniale. Cet article prend appui sur l’analyse des procès tenus, entre 1923 et 1939, au tribunal du premier degré d’Abidjan, il vise à décrire les argumentations contradictoires par lesquelles femmes et hommes expliquent leurs différends dans l’espace du prétoire. Les registres issus des « juridictions indigènes » permettent également d’apprécier sur quels repères se fondent ...

  9. Massignon face au sionisme

    OpenAIRE

    Mayeres, Agathe

    2010-01-01

    En 1916, Louis Massignon participe aux négociations franco-britanniques qui envisagent, dans la perspective de la capitulation probable des empires centraux, le futur partage de l’Empire ottoman. Dans ce contexte, Massignon cherche à se situer face la question sioniste qui, pour lui, est avant tout un problème de politique orientale.Sous l’influence d'Aaron Aaronsohn, l’islamologue éprouve d’abord pour les pionniers d’Eretz Israel, au regard de leurs réalisations agricoles, une sympathie enth...

  10. Des ignames au riz

    OpenAIRE

    Ivanoff, Jacques

    2003-01-01

    L'igname a toujours été une nourriture importante pour les populations littorales et nomades du monde insulindien. Cependant, avec l'installation du héros civilisateur Gaman le Malais chez le peuple de la reine Sibian, le riz va devenir la composante essentielle des repas moken. En intégrant Gaman en son sein, la société moken va devoir répondre au double défi posé par la menace de la riziculture et de l'islam. En donnant femme à Gaman, en adoptant le nomadisme pour échapper à l'islam ...

  11. Vivre, vivre au Japon

    OpenAIRE

    Tardits, Manuel

    2014-01-01

    Comment faire face au caractère récurrent des catastrophes naturelles et liées à l’homme ? À la prévention, on se doit d’adjoindre une vision écologique plus large et renouvelée. Un débat sur le modèle énergétique du nucléaire et sur nos modèles de développement urbains et sociétaux s’impose.

  12. Introduction au titre I

    OpenAIRE

    2015-01-01

    Pline a eu dans sa carrière d’homme public à défendre les intérêts de l’Etat et des particuliers, à épurer des comptes, à juger et arbitrer. Ainsi le voulait l’ordonnancement du cursus honorum du Bas-Empire, héritier sur tous ces points de la tradition des charges publiques de la République. Les premières tâches du petiturus furent essentiellement judiciaires - on songe au vigintivirat - et elles se poursuivirent par des fonctions de moyenne importance (préture consulat) puis de haute adminis...

  13. Vehicle emissions of greenhouse gases and related tracers from a tunnel study: : CO: CO2, N2O: CO2, CH4: CO2, O2: CO2 ratios, and the stable isotopes 13C and 18O in CO2 and CO

    NARCIS (Netherlands)

    Popa, Maria Elena; Vollmer, M. K.; Jordan, A.; Brand, W. A.; Pathirana, S. L.; Rothe, M.; Röckmann, T.

    2014-01-01

    Measurements of CO2, CO, N2O and CH4 mole fractions, O2/N2 ratios and the stable isotopes 13C and 18O in CO2 and CO have been performed in air samples from the Islisberg highway tunnel (Switzerland). The molar CO : CO2 ratios, with an average of (4.15 ± 0.34) ppb:ppm, are lower than reported in prev

  14. 农田土壤主要温室气体(CO2、CH4、N2O)的源/汇强度及其温室效应研究进展%Research advances on source/sink intensities and greenhouse effects of CO2,CH4 and N2O in agricultural soils

    Institute of Scientific and Technical Information of China (English)

    张玉铭; 胡春胜; 张佳宝; 董文旭; 王玉英; 宋利娜

    2011-01-01

    气候变化是当今全球面临的重大挑战,人类社会生产生活引起的温室气体排放是全球气候变暖的主要原因.大气中CO2、CH4和N2O是最重要的温室气体,对温室效应的贡献率占了近80%.据估计,大气中每年有5%~20%的CO2、15%~30%的CH4、80%~90%的N2O来源于土壤,而农田土壤是温室气体的重要排放源.本文重点阐述了农田土壤温室气体产生、排放或吸收机理及其影响因素,指出土地利用方式和农业生产力水平等人为控制因素通过影响土壤和作物生长条件来影响农田土壤温室气体产生与排放或吸收.所以,我们可以从人类活动对农田生态系统的影响着手,通过改善农业生产方式和作物生长条件来探索温室气体减排措施,达到固碳/氨增汇的目的.对国内外关于农田温室气体排放的源/汇强度及其综合温室效应评估的最新研究进展进行了综述,指出正确估算与评价农田土壤温室气体的源/汇强度及其对大气中主要温室气体浓度变化的贡献,有助于为温室气体减排以及减少气候变化预测的不确定性提供理论依据.%Climate change is an increasing global challenge. Greenhouse gas emission via anthropogenic processes is the main cause of global warming. CO3, CH4, and N2O are the main greenhouse gases, accounting for =80% of greenhouse effect. It is estimated that each year, 5%~20% of CO2, 15%-30% of CR, and 80%~90% of N2O in air are emitted from soils. Agricultural soils are the main sources of greenhouse gas emission. This work expatiated the mechanisms and affecting factors of greenhouse gas formation, emission and absorption in agricultural soils. And the contribution of farmland ecosystem to greenhouse effects was discussed. It was indicated that anthropogenic factors such as land use and agricultural activity influenced greenhouse gas formation, emission and absorption in agricultural soils. Because anthropogenic processes affected agricultural ecosystems, greenhouse gas emission reductions for stabilized carbon and nitrogen were possible through improved agricultural cultivation and production systems. This study summarized the latest research advances in source/sink intensities of greenhouse gas emissions from farmlands and how that contributes to greenhouse effect. The study suggested that accurate estimation of source/sink intensities of greenhouse gases and ap-propriate assessments of greenhouse gas effects were the theoretical basis for reducing greenhouse gas emissions and uncertainties inpredicting climate change.

  15. Photoelectrochemical studies of DNA-tagged biomolecules on Au and Au/Ni/Au multilayer nanowires

    Directory of Open Access Journals (Sweden)

    Swaminathan Viswanathan

    2011-01-01

    Full Text Available Abstract The use of nanowires (NWs for labeling, sensing, and sorting is the basis of detecting biomolecules attached on NWs by optical and magnetic properties. In spite of many advantages, the use of biomolecules-attached NWs sensing by photoelectrochemical (PEC study is almost non-existent. In this article, the PEC study of dye-attached single-stranded DNA on Au NWs and Au-Ni-Au multilayer NWs prepared by pulse electrodeposition are investigated. Owing to quantum-quenching effect, the multilayer Au NWs exhibit low optical absorbance when compared with Au NWs. The tagged Au NWs show good fluorescence (emission at 570 nm, indicating significant improvement in the reflectivity. Optimum results obtained for tagged Au NWs attached on functionalized carbon electrodes and its PEC behavior is also presented. A twofold enhancement in photocurrent is observed with an average dark current of 10 μA for Au NWs coated on functionalized sensing electrode. The importance of these PEC and optical studies provides an inexpensive and facile processing platform for Au NWs that may be suitable for biolabeling applications.

  16. Le marketing au concret

    OpenAIRE

    Gaglio, Gérald

    2010-01-01

    Le terme “marketing” suscite généralement la méfiance, car il est spontanément associé à l’idée de manipulation. Au-delà, que font, concrètement, les “gens du marketing” ? Afin d’apporter des pistes de réponse à cette question, nous nous penchons dans cet article sur les enjeux relatifs à un matériau censé alimenter les réflexions et décisions des marketeurs : les études qualitatives de marketing research réalisées dans le cadre de réunions de consommateurs. Cette approche nous conduit à expl...

  17. Introduction au titre II

    OpenAIRE

    2015-01-01

    159. L’objet de notre propos est de démontrer que l’Administration dispose, à la suite du juge, d’un véritable pouvoir normatif. L’admettre suppose d’en identifier les différentes manifestations qui s’expriment essentiellement par voie de circulaires administratives, de réponses ministérielles et d’avis administratifs et qui ne sauraient être assimilées au pouvoir réglementaire que l’Administration détient par ailleurs. L’ordre logique de la démonstration sera donc semblable à celui adopté po...

  18. Introduction au titre I

    OpenAIRE

    2015-01-01

    330. La parenté une construction sociale modelant le donné biologique. Au développement et à la multiplicité des modèles familiaux et conjugaux, correspond inévitablement une pluralité des formes d’expression de la parenté. L’image de l’arbre fait apparaître de manière simple et rapide l’appartenance à la parenté. Clarifier la notion passe par la mise en exergue de ses critères déterminants. Quel lien détermine la continuité généalogique : lien génétique ou lien volontaire ? Le droit doit rép...

  19. Differential systems of flux and concentrations of a mixture in the separation by a plant (1963); Systemes differente des flux et des concentrations d'un melange en separation par une usine etagee (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Bouligand, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-11-15

    The study of transient flux and concentrations of a mixture in the separation by a plant with different interdependent stages leads to an examination of the solutions of certain types of differential systems. These systems are obtained from the representative graph of the plant and have a structural form. By Olga TAUSSKY's theorem and the introduction of steerable distances, the solutions of these systems are chiefly examined in their asymptotic behaviour. The appendix shows that solutions of partial differential equations relative to plants made of cascades with a slight separation have analogous properties. (author) [French] La recherche des regimes transitoires des flux et des concentrations d'un melange en separation par une usine etagee de forme quelconque conduit a etudier les solutions de certains types de systemes differentiels. Ces systemes sont deduits du graphe representatif de l'usine, et apparaissent sous une forme structuree. A l'aide du theoreme d'Olga TAUSSKY et par l'introduction d'ecarts orientes, les solutions de ces systemes sont principalement examinees dans leur comportement asymptotique. Un appendice montre que les solutions des systemes d'equations aux derivees partielles des usines en cascades a tres faible separation admettent des proprietes analogues. (auteur)

  20. Multifragmentation in Au + Au collisions studied with AMD-V

    International Nuclear Information System (INIS)

    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 197Au + 197Au 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 α-particle and intermediate fragments estimated too small. (S.Y.)

  1. 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...

  2. Comparative study of anchoring groups for molecular electronics: structure and conductance of Au-S-Au and Au-NH2-Au junctions

    DEFF Research Database (Denmark)

    Kristensen, Iben Sig; Mowbray, Duncan; Thygesen, Kristian Sommer;

    2008-01-01

    selectivity towards atop-gold configurations, S shows large variability in its bonding geometries. As a result, the conductance of the Au-NH2-Au junction is less sensitive to the structure of the gold contacts than the Au-S-Au junction. These findings support recent experiments which show that amine...

  3. 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...

  4. Flow in Au+Au collisions at RHIC

    Science.gov (United States)

    Belt Tonjes, Marguerite; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; 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, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; 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.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L. H.; Wosiek, B.; Wozniak, K.; Wuosmaa, A. H.; Wyslouch, B.

    2004-08-01

    The study of flow can provide information on the initial state dynamics and the degree of equilibration attained in heavy-ion collisions. This contribution presents results for both elliptic and directed flow as determined from data recorded by the PHOBOS experiment in Au+Au runs at RHIC at \\sqrt{s_{{\\rm NN}}} = 19.6, 130 and 200 GeV. The PHOBOS detector provides a unique coverage in pseudorapidity for measuring flow at RHIC. The systematic dependence of flow on pseudorapidity, transverse momentum, centrality and energy is discussed.

  5. 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.

  6. Relative Distribution of Au48+ ~ Au52+ in Au Plasma by Ionization Dynamics

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhi-Yan; ZHU Zheng-He; JIANG Gang

    2003-01-01

    The present work proposes a theoretical method called ionization dynamics to derive the ionic charge state distribution. Using relativistic quantum mechanics to calculate the energy level lifetime and average ionic lifetime of each ion, the first-order ionization rate constant can be obtained. Based on these data, from the solution of differential equations for consecutive-irreversible ionization reactions, one will be able to derive the ionic charge state distribution.The calculated average positive charge 49.24 of Au48+ ~ Au52+ and their relative distribution are in good agreement with the results of Lawrence Livermore National Laboratory.

  7. Biosynthesis and stabilization of Au and Au-Ag alloy nanoparticles by fungus, Fusarium semitectum

    International Nuclear Information System (INIS)

    Crystallized and spherical-shaped Au and Au-Ag alloy nanoparticles have been synthesized and stabilized using a fungus, F . semitectum in an aqueous system. Aqueous solutions of chloroaurate ions for Au and chloroaurate and Ag+ ions (1 : 1 ratio) for Au-Ag alloy were treated with an extracellular filtrate of F . semitectum biomass for the formation of Au nanoparticles (AuNP) and Au-Ag alloy nanoparticles (Au-AgNP). Analysis of the feasibility of the biosynthesized nanoparticles and core-shell alloy nanoparticles from fungal strains is particularly significant. The resultant colloidal suspensions are highly stable for many weeks. The obtained Au and Au-Ag alloy nanoparticles were characterized by the surface plasmon resonance (SPR) peaks using a UV-vis spectrophotometer, and the structure, morphology and size were determined by Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), and transmission electron microscopy (TEM). Possible optoelectronics and medical applications of these nanoparticles are envisaged.

  8. Onset of nuclear matter expansion in Au+Au collisions

    CERN Document Server

    Crochet, Philippe; Gobbi, A; Donà, R; Coffin, J P; Fintz, P; Guillaume, G; Jundt, F; Kühn, C E; Roy, C; De Schauenburg, B; Tizniti, L; Wagner, P; Alard, J P; Amouroux, V; Andronic, A; Basrak, Z; Bastid, N; Belyaev, I; Best, D; Biegansky, J; Butà, A; Caplar, R; Cindro, N; Dupieux, P; Dzelalija, M; Fan, Z G; Fodor, Z; Fraysse, L; Freifelder, R P; Herrmann, N; Hildenbrand, K D; Hong, B H; Jeong, S C; Kecskeméti, J; Kirejczyk, M; Koncz, P; Korolija, M; Kotte, R; Lebedev, A; Leifels, Y; Man'ko, V I; Moisa, D; Mösner, J; Neubert, W; Pelte, D; Petrovici, M; Pinkenburg, C H; Pras, P; Ramillien, V; Reisdorf, W; Ritman, J L; Sadchikov, A G; Schüll, D; Seres, Z; Sikora, B; Simion, V; Siwek-Wilczynska, K; Sodan, U; Teh, K M; Trzaska, M; Vasilev, M A; Wang, G S; Wessels, J P; Wienold, T; Wisniewski, K; Wohlfarth, D; Zhilin, A V

    1997-01-01

    Using the FOPI detector at GSI Darmstadt, excitation functions of collective flow components were measured for the Au+Au system, in the reaction plane and out of this plane, at seven incident energies ranging from 100AMeV to 800AMeV. The threshold energies, corresponding to the onset of sideward-flow (balance energy) and squeeze-out effect (transition energy), are extracted from extrapolations of these excitation functions toward lower beam energies for charged products with Z>2. The transition energy is found to be larger than the balance energy. The impact parameter dependence of both balance and transition energies, when extrapolated to central collisions, suggests comparable although slightly higher values than the threshold energy for the radial flow. The relevant parameter seems to be the energy deposited into the system in order to overcome the attractive nuclear forces.

  9. Nuclear Modification of Jet Fragmentation in Au+Au Collisions

    Science.gov (United States)

    Rowan, Zachary; Phenix Collaboration

    2015-10-01

    The characterization of energy in the quark gluon plasma is facilitated by measurements of modifications to the observed jet fragmentation. A favorable channel of study relies on direct photons created in the initial parton interactions of heavy ion collisions. Such a photon traverses the created medium unscathed and grants us a proxy for the transverse momentum of an away side jet. PHENIX Au+Au data recorded at √{sNN} = 200 GeV during RHIC run 14 benefit from the background rejection capability of the silicon vertex detector, enabling the extraction of a higher purity hadron signal. This advantage, combined with a larger integrated luminosity, allows previous PHENIX measurements of fragmentation functions to be extended to greater jet energies. In this talk, the status of the analysis of direct photon hadron correlations with the new data set will be discussed.

  10. Global polarization measurement in Au+Au collisions

    CERN Document Server

    Abelev, B I; Ahammed, Z; Anderson, B D; Arkhipkin, D; Averichev, G S; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Baumgart, S; Belaga, V V; Bellingeri-Laurikainen, A; Bellwied, R; Benedosso, F; Betts, R R; Bhardwaj, S; Bhasin, A; Bhati, A K; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Blyth, S L; Bombara, M; Bonner, B E; Botje, M; Bouchet, J; Brandin, A V; Bravar, A; Burton, T P; Bystersky, M; Cai, X Z; Caines, H; Calderón de la Barca-Sanchez, M; Callner, J; Catu, O; Cebra, D; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, J Y; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Chung, S U; Coffin, J P; Cormier, T M; Cosentino, M R; Cramer, J G; Crawford, H J; Das, D; Dash, S; Daugherity, M; De Moura, M M; Dedovich, T G; De Phillips, M; Derevshchikov, A A; Didenko, L; Dietel, T; Djawotho, P; Dogra, S M; Dong, X; Drachenberg, J L; Draper, J E; Du, F; Dunin, V B; Dunlop, J C; Dutta-Majumdar, 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; Feng, A; Filip, P; Finch, E; Fine, V; Fisyak, Yu; Fu, J; Gagliardi, C A; Gaillard, L; Ganti, M S; García-Solis, E; Ghazikhanian, V; Ghosh, P; Gorbunov, Y N; Gos, H; Grebenyuk, O; Grosnick, D; Grube, B; Guertin, S M; Guimaraes, K S F F; Gupta, N; Haag, B; Hallman, T J; Hamed, A; Harris, J W; He, W; Heinz, M; Henry, T W; Heppelmann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffman, A M; Hoffmann, G W; Hofman, D J; Hollis, R S; Horner, M J; Huang, H Z; Hughes, E W; Humanic, T J; Igo, G; Iordanova, A; Jacobs, P; Jacobs, W W; Jakl, P; Jia, F; Jones, P G; Judd, E G; Kabana, S; Kang, K; Kapitan, J; Kaplan, M; Keane, D; Kechechyan, A; Kettler, D; Khodyrev, V Yu; Kiryluk, J; Kisiel, A; Kislov, E M; Klein, S R; Knospe, A G; Kocoloski, A; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kouchpil, V; Kowalik, K L; Kravtsov, P; Kravtsov, V I; Krüger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kurnadi, P; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; La Pointe, S; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Lee, C H; Lehocka, S; Le Vine, M J; Li, C; Li, Q; Li, Y; Lin, G; Lin, X; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, J; Liu, L; Ljubicic, T; Llope, W J; Longacre, R S; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, J G; Ma, Y G; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Melnik, Yu M; Meschanin, A; Millane, J; Miller, M L; Minaev, N G; Mioduszewski, S; Mischke, A; Mitchell, J; Mohanty, B; Morozov, D A; Munhoz, M G; Nandi, B K; Nattrass, C; Nayak, T K; Nelson, J M; Nepali, C; Netrakanti, P K; Nogach, L V; Nurushev, S B; Odyniec, Grazyna Janina; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Pachr, M; Pal, S K; Panebratsev, Yu A; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevozchikov, V; Perkins, C; Peryt, W; Phatak, S C; Planinic, M; Pluta, J; Poljak, N; Porile, N; Poskanzer, A M; Potekhin, M V; Potrebenikova, E V; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Qattan, I A; Raniwala, R; Raniwala, S; Ray, R L; Relyea, D; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M J; Sahoo, R; Sakrejda, I; Sakuma, T; Salur, S; Sandweiss, J; Sarsour, M; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Seger, J; Selyuzhenkov, I; Seyboth, P; Shabetai, A; Shahaliev, E; Shao, M; Sharma, M; Shen, W Q; Shimansky, S S; Sichtermann, E P; Simon, F; Singaraju, R N; Smirnov, N; Snellings, R; Sørensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Staszak, D; Stock, R; Strikhanov, M N; Stringfellow, B C; Suaide, A A P; Suarez, M C; Subba, N L; Sumbera, M; Sun, X M; Sun, Z; Surrow, B; Symons, T J M; Szanto de Toledo, A; Takahashi, J; Tang, A H; Tarnowsky, T J; Thomas, J H; Timmins, A R; Timoshenko, S; Tokarev, M; Trainor, T A; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; Van der Kolk, N; Van Leeuwen, M; Van der Molen, A M; Varma, R; Vasilevski, I M; Vasilev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Wada, M; Waggoner, W T; Wang, F; Wang, G; Wang, J S; Wang, X L; Wang, Y; Webb, J C; Westfall, G D; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wu, J; Wu, Y; Xu, N; Xu, Q H; Xu, Z; Yepes, P; Yoo, I K; Yue, Q; Yurevich, V I; Zawisza, M; Zhan, W; Zhang, H; Zhang, W M; Zhang, Y; Zhang, Z P; Zhao, Y; Zhong, C; Zhou, J; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N; Zuo, J X

    2007-01-01

    The system created in non-central relativistic nucleus-nucleus collisions possesses large orbital angular momentum. Due to spin-orbit coupling, particles produced in such a system could become globally polarized along the direction of the system angular momentum. We present the results of Lambda and anti-Lambda hyperon global polarization measurements in Au+Au collisions at sqrt{s_NN}=62.4 GeV and 200 GeV performed with the STAR detector at RHIC. The observed global polarization of Lambda and anti-Lambda hyperons in the STAR acceptance is consistent with zero within the precision of the measurements. The obtained upper limit, |P_{Lambda,anti-Lambda}| <= 0.02, is compared to the theoretical values discussed recently in the literature.

  11. Global polarization measurement in Au+Au collisions

    Science.gov (United States)

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Averichev, G. S.; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Baumgart, S.; Belaga, V. V.; Bellingeri-Laurikainen, A.; Bellwied, R.; Benedosso, F.; Betts, R. R.; Bhardwaj, S.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Blyth, S.-L.; Bombara, M.; Bonner, B. E.; Botje, M.; Bouchet, J.; Brandin, A. V.; Burton, T. P.; Bystersky, M.; Cai, X. Z.; Caines, H.; Sánchez, M. Calderón De La Barca; Callner, J.; Catu, O.; Cebra, D.; Cervantes, M. C.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Chung, S. U.; Clarke, R. F.; Codrington, M. J. M.; Coffin, J. P.; Cormier, T. M.; Cosentino, M. R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Daugherity, M.; Moura, M. M. De; Dedovich, T. G.; Dephillips, M.; Derevschikov, A. A.; Didenko, L.; Dietel, T.; Djawotho, P.; Dogra, S. M.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, F.; Dunin, V. B.; Dunlop, J. C.; Mazumdar, M. R. Dutta; Edwards, W. R.; Efimov, L. G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Feng, A.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Fu, J.; Gagliardi, C. A.; Gaillard, L.; Ganti, M. S.; Garcia-Solis, E.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y. N.; Gos, H.; Grebenyuk, O.; Grosnick, D.; Grube, B.; Guertin, S. M.; Guimaraes, K. S. F. F.; Gupta, A.; Gupta, N.; Haag, B.; Hallman, T. J.; Hamed, A.; Harris, J. W.; He, W.; Heinz, M.; Henry, T. W.; Heppelmann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffman, A. M.; Hoffmann, G. W.; Hofman, D. J.; Hollis, R. S.; Horner, M. J.; Huang, H. Z.; Hughes, E. W.; Humanic, T. J.; Igo, G.; Iordanova, A.; Jacobs, P.; Jacobs, W. W.; Jakl, P.; Jones, P. G.; Judd, E. G.; Kabana, S.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Kettler, D.; Khodyrev, V. Yu.; Kiryluk, J.; Kisiel, A.; Kislov, E. M.; Klein, S. R.; Knospe, A. G.; Kocoloski, A.; Koetke, D. D.; Kollegger, T.; Kopytine, M.; Kotchenda, L.; Kouchpil, V.; Kowalik, K. L.; Kravtsov, P.; Kravtsov, V. I.; Krueger, K.; Kuhn, C.; Kulikov, A. I.; Kumar, A.; Kurnadi, P.; Kuznetsov, A. A.; Lamont, M. A. C.; Landgraf, J. M.; Lange, S.; Lapointe, S.; Laue, F.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C.-H.; Lehocka, S.; Levine, M. J.; Li, C.; Li, Q.; Li, Y.; Lin, G.; Lin, X.; Lindenbaum, S. J.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Love, W. A.; Lu, Y.; Ludlam, T.; Lynn, D.; Ma, G. L.; Ma, J. G.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Martin, L.; Matis, H. S.; Matulenko, Yu. A.; McShane, T. S.; Meschanin, A.; Millane, J.; Miller, M. L.; Minaev, N. G.; Mioduszewski, S.; Mischke, A.; Mitchell, J.; Mohanty, B.; Morozov, D. A.; Munhoz, M. G.; Nandi, B. K.; Nattrass, C.; Nayak, T. K.; Nelson, J. M.; Nepali, C.; Netrakanti, P. K.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Okorokov, V.; Olson, D.; Pachr, M.; Pal, S. K.; Panebratsev, Y.; Pavlinov, A. I.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S. C.; Planinic, M.; Pluta, J.; Poljak, N.; Porile, N.; Poskanzer, A. M.; Potekhin, M.; Potrebenikova, E.; Potukuchi, B. V. K. S.; Prindle, D.; Pruneau, C.; Pruthi, N. K.; Putschke, J.; Qattan, I. A.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Relyea, D.; Ridiger, A.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M. J.; Sahoo, R.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sarsour, M.; Sazhin, P. S.; Schambach, J.; Scharenberg, R. P.; Schmitz, N.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shabetai, A.; Shahaliev, E.; Shao, M.; Sharma, M.; Shen, W. Q.; Shimanskiy, S. S.; Sichtermann, E. P.; Simon, F.; Singaraju, R. N.; Smirnov, N.; Snellings, R.; Sorensen, P.; Sowinski, J.; Speltz, J.; Spinka, H. M.; Srivastava, B.; Stadnik, A.; Stanislaus, T. D. S.; Staszak, D.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Subba, N. L.; Sumbera, M.; Sun, X. M.; Sun, Z.; Surrow, B.; Symons, T. J. M.; Toledo, A. Szanto De; Takahashi, J.; Tang, A. H.; Tarnowsky, T.; Thomas, J. H.; Timmins, A. R.; Timoshenko, S.; Tokarev, M.; Trainor, T. A.; Trentalange, S.; Tribble, R. E.; Tsai, O. D.; Ulery, J.; Ullrich, T.; Underwood, D. G.; Buren, G. Van; Kolk, N. Van Der; Leeuwen, M. Van; Molen, A. M. Vander; Varma, R.; Vasilevski, I. M.; Vasiliev, A. N.; Vernet, R.; Vigdor, S. E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Wada, M.; Waggoner, W. T.; Wang, F.; Wang, G.; Wang, J. S.; Wang, X. L.; Wang, Y.; Webb, J. C.; Westfall, G. D.; , C. Whitten, Jr.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, J.; Wu, Y.; Xu, N.; Xu, Q. H.; Xu, Z.; Yepes, P.; Yoo, I.-K.; Yue, Q.; Yurevich, V. I.; Zawisza, M.; Zhan, W.; Zhang, H.; Zhang, W. M.; Zhang, Y.; Zhang, Z. P.; Zhao, Y.; Zhong, C.; Zhou, J.; Zoulkarneev, R.; Zoulkarneeva, Y.; Zubarev, A. N.; Zuo, J. X.

    2007-08-01

    The system created in noncentral relativistic nucleus-nucleus collisions possesses large orbital angular momentum. Because of spin-orbit coupling, particles produced in such a system could become globally polarized along the direction of the system angular momentum. We present the results of Λ and Λ¯ hyperon global polarization measurements in Au+Au collisions at sNN=62.4 and 200 GeV performed with the STAR detector at the BNL Relativistic Heavy Ion Collider (RHIC). The observed global polarization of Λ and Λ¯ hyperons in the STAR acceptance is consistent with zero within the precision of the measurements. The obtained upper limit, |PΛ,Λ¯|⩽0.02, is compared with the theoretical values discussed recently in the literature.

  12. Constructing Gold-thiolate Oligomers and Polymers on Au(111) Based on the Linear S-Au-S Geometry

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Deen [ORNL; Dai, Sheng [ORNL

    2009-01-01

    Although neat gold-thiolate oligomers and polymers made of linear S-Au-S bonds have been well-known, observation of RS-Au-SR linear complexes (RS-being an alkylthiolate group) on Au(111) has been reported only recently. On the basis of the unique geometry and bonding of the RS-Au-SR complex on Au(111), we construct simple geometric models of Au-SR oligomers and polymers on Au(111) by fusing linear S-Au-S units matched to the underlying Au(111) surface lattice. We then optimize these models by density functional theory. The hexagonal geometry of the Au(111) lattice determines three possible angles (60{sup o}, 120{sup o}, and 180{sup o}) for connecting two linear S-Au-S units, which lead to isomerism of the Au-SR oligomers and polymer on Au(111). Here we explore open dimers, trimers, and tetramers and cyclic trimers, tetramers, and hexamers of the Au-SR oligomers on Au(111). We also examine four isomers of the Au-SR polymer on Au(111). We find that the 120{sup o} Au-S-Au angle is preferred in constructing both oligomeric and polymeric isomers. The two polymeric isomers with 120{sup o} Au-S-Au angles are found to be energetically competitive with a previous model proposed for the Au-SR polymer on Au(111). We also discuss potential ways to create Au-SR oligomers on Au(111).

  13. Constructing Gold-Thiolate Oligomers and Polymers on Au(111) Based on the Linear S-Au-S Geometry

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Sheng [ORNL; Jiang, Deen [ORNL

    2009-01-01

    Although neat gold-thiolate oligomers and polymers made of linear S-Au-S bonds have been well-known, observation of RS-Au-SR linear complexes (RS- being an alkylthiolate group) on Au(111) has been reported only recently. On the basis of the unique geometry and bonding of the RS-Au-SR complex on Au(111), we construct simple geometric models of Au-SR oligomers and polymers on Au(111) by fusing linear S-Au-S units matched to the underlying Au(111) surface lattice. We then optimize these models by density functional theory. The hexagonal geometry of the Au(111) lattice determines three possible angles (60{sup o}, 120{sup o}, and 180{sup o}) for connecting two linear S-Au-S units, which lead to isomerism of the Au-SR oligomers and polymer on Au(111). Here we explore open dimers, trimers, and tetramers and cyclic trimers, tetramers, and hexamers of the Au-SR oligomers on Au(111). We also examine four isomers of the Au-SR polymer on Au(111). We find that the 120{sup o} Au-S-Au angle is preferred in constructing both oligomeric and polymeric isomers. The two polymeric isomers with 120{sup o} Au-S-Au angles are found to be energetically competitive with a previous model proposed for the Au-SR polymer on Au(111). We also discuss potential ways to create Au-SR oligomers on Au(111).

  14. d + Au hadron correlation measurements at PHENIX

    International Nuclear Information System (INIS)

    In these proceedings, we discuss recent results from d + Au collisions in PHENIX ridge related measurements and their possible hydrodynamic origin. We present the v2 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 v2 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

  15. 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.

  16. Introduction au filtre de Kalman

    OpenAIRE

    Alazard, Daniel

    2006-01-01

    Ce document est une introduction au filtre optimal de Kalman appliquée aux systèmes linéaires. On suppose connues la théorie des asservissements linéaires et du filtrage fréquentiel (continu et discret) ainsi que les notions d'états pour représenter les systèmes dynamiques linéaires.

  17. 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...

  18. 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.

  19. Thin-films interdiffusion Ti/Pd/Au, Ti/Au/Pd

    International Nuclear Information System (INIS)

    Rutherford backscattering spectroscopy (RBS) is used to study the interdiffusion in Ti/Pd/Au and Ti/Au/Pd thin films system. The purpose of our study is to prepare an alloy of high resistance against corrosion, due to its important use in space industries, optical and visual receivers. In addition to another scientific results for future applications. Interdiffusion in the Ti/Pd/Au thin film system is measured using Rutherford backscattering. Interdiffusion rates of Pd/Au for temperatures between 200 and 490 centigrade degree have been correlated with the defect structure of the films. Air, as compared with vacuum, annealing enhances interdiffusion in the Ti/Au couple and inhibits interdiffusion in Ti/Pd, Ti/Pd and Ti/Au interdiffusion in the Ti/Pd/Au and Ti/Au/Pd ternary systems is strongly reduced in comparison with interdiffusion in the corresponding Ti/Pd or Ti/Au couples for vacuum annealing. (Author)

  20. Initial state geometry and fluctuations in Au+Au, Cu+Au and U+U collisions at RHIC

    OpenAIRE

    Schenke, Bjoern; Tribedy, Prithwish; Venugopalan, Raju

    2014-01-01

    We study within the IP-Glasma and two-component MC-Glauber models the effects of initial state geometry and fluctuations on multiplicities and eccentricities for several collision species at the Relativistic Heavy Ion Collider (RHIC). These include copper-gold (Cu+Au), gold-gold (Au+Au), and uranium-uranium (U+U) collisions. The multiplicity densities per participant pair are very similar in all systems studied. Ellipticities vary strongly between collision systems, most significantly for cen...

  1. L’olivier au Maroc

    OpenAIRE

    El Mouhtadi Issam; Agouzzal Mohamed; Guy François

    2014-01-01

    L’olivier est une culture traditionnelle sur le pourtour de la Méditerranée. Il est donc naturel de trouver cet arbre au Maroc où il est présent depuis des siècles. Cultivé surtout traditionnellement jusqu’à ses dernières années, il fait l’objet maintenant d’un plan de valorisation très ambitieux pour non seulement garder le Royaume à son niveau actuel (2e producteur mondial pour l’olive de conserve et 6e pour l’huile d’olive) mais pour conq...

  2. Predicted Habitat Suitability for Porites Corals in the Au'au Channel Region

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This raster denotes predicted habitat suitability for Porites in the Au'au Channel region. Maximum Entropy (MaxEnt) modeling software was used to create this...

  3. Predicted Habitat Suitability for Leptoseris Corals in the Au'au Channel Region

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This raster denotes predicted habitat suitability for Leptoseris in the Au'au Channel region. Maximum Entropy (MaxEnt) modeling software was used to create this...

  4. Predicted Habitat Suitability for All Mesophotic Corals in the Au'au Channel Region

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is located between the islands of Maui, Lanai, Molokai and Kahoolawe, and includes the Au'au Channel as well as parts of the Kealaikahiki, Alalakeiki...

  5. Predicted Habitat Suitability for Porites in the Au'au Channel Region

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This raster denotes predicted habitat suitability for Porites in the Au'au Channel region. Maximum Entropy (MaxEnt) modeling software was used to create this...

  6. Predicted Habitat Suitability for All Mesophotic Corals in the Au'au Channel Region

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This raster denotes predicted habitat suitability for all mesophotic corals in the Au'au Channel region. Maximum Entropy (MaxEnt) modeling software was used to...

  7. Predicted Habitat Suitability for Montipora Corals in the Au'au Channel Region

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This raster denotes predicted habitat suitability for Montipora in the Au'au Channel region. Maximum Entropy (MaxEnt) modeling software was used to create this...

  8. Predicted Habitat Suitability for Leptoseris in the Au'au Channel Region

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This raster denotes predicted habitat suitability for Leptoseris in the Au'au Channel region. Maximum Entropy (MaxEnt) modeling software was used to create this...

  9. A Study of Parton Energy Loss in Au+Au Collisions at RHIC using Transport Theory

    OpenAIRE

    Nara, Y.; Vance, S. E.; Csizmadia, P.

    2001-01-01

    Parton energy loss in Au+Au collisions at RHIC energies is studied by numerically solving the relativistic Boltzmann equation for the partons including $2 \\leftrightarrow 2$ and $2 \\to 2 + final state radiation$ collision processes. Final particle spectra are obtained using two hadronization models; the Lund string fragmentation and independent fragmentation models. Recent, preliminary $\\pi^0$ transverse momentum distributions from central Au+Au collisions at RHIC are reproduced using gluon-g...

  10. Bright, NIR-emitting Au23 from Au25: characterization and applications including biolabeling.

    Science.gov (United States)

    Muhammed, Madathumpady Abubaker Habeeb; Verma, Pramod Kumar; Pal, Samir Kumar; Kumar, R C Arun; Paul, Soumya; Omkumar, Ramakrishnapillai Vyomakesannair; Pradeep, Thalappil

    2009-10-01

    A novel interfacial route has been developed for the synthesis of a bright-red-emitting new subnanocluster, Au(23), by the core etching of a widely explored and more stable cluster, Au(25)SG(18) (in which SG is glutathione thiolate). A slight modification of this procedure results in the formation of two other known subnanoclusters, Au(22) and Au(33). Whereas Au(22) and Au(23) are water soluble and brightly fluorescent with quantum yields of 2.5 and 1.3 %, respectively, Au(33) is organic soluble and less fluorescent, with a quantum yield of 0.1 %. Au(23) exhibits quenching of fluorescence selectively in the presence of Cu(2+) ions and it can therefore be used as a metal-ion sensor. Aqueous- to organic-phase transfer of Au(23) has been carried out with fluorescence enhancement. Solvent dependency on the fluorescence of Au(23) before and after phase transfer has been studied extensively and the quantum yield of the cluster varies with the solvent used. The temperature response of Au(23) emission has been demonstrated. The inherent fluorescence of Au(23) was used for imaging human hepatoma cells by employing the avidin-biotin interaction. PMID:19711391

  11. Initial state geometry and fluctuations in Au+Au, Cu+Au and U+U collisions at RHIC

    CERN Document Server

    Schenke, Bjoern; Venugopalan, Raju

    2014-01-01

    We study within the IP-Glasma and two-component MC-Glauber models the effects of initial state geometry and fluctuations on multiplicities and eccentricities for several collision species at the Relativistic Heavy Ion Collider (RHIC). These include copper-gold (Cu+Au), gold-gold (Au+Au), and uranium-uranium (U+U) collisions. The multiplicity densities per participant pair are very similar in all systems studied. Ellipticities vary strongly between collision systems, most significantly for central collisions, while fluctuation driven odd moments vary little between systems. Event-by-event distributions of eccentricities in mid-central collisions are wider in Cu+Au relative to Au+Au and U+U systems. An anti-correlation between multiplicity and eccentricity is observed in ultra central U+U collisions which is weaker in the IP-Glasma model than the two-component MC-Glauber model. In ultra central Au+Au collisions the two models predict opposite signs for the slope of this correlation. Measurements of elliptic flo...

  12. L’olivier au Maroc

    Directory of Open Access Journals (Sweden)

    El Mouhtadi Issam

    2014-03-01

    Full Text Available L’olivier est une culture traditionnelle sur le pourtour de la Méditerranée. Il est donc naturel de trouver cet arbre au Maroc où il est présent depuis des siècles. Cultivé surtout traditionnellement jusqu’à ses dernières années, il fait l’objet maintenant d’un plan de valorisation très ambitieux pour non seulement garder le Royaume à son niveau actuel (2e producteur mondial pour l’olive de conserve et 6e pour l’huile d’olive mais pour conquérir de nouveaux marchés au niveau mondial et profiter ainsi de l’engouement que connaît cette huile reconnue pour ses bienfaits. Le plan national « Maroc Vert » permet ainsi, grâce à des subventions conséquentes, non seulement de renouveler les vergers existant avec la variété traditionnelle picholine du Maroc, mais également la plantation de nouvelles variétés en super-intensif dans le but d’industrialiser au maximum de nouveaux vergers. Il en est de même pour la transformation des olives en huile de bonne qualité avec la mise en place d’unités de trituration modernes qui doivent supplanter à terme la multitude de « maâsra » et réduire ainsi l’impact environnemental dû aux margines. L’olive ne sera plus dans l’avenir que représentée par son huile et ses formes comestibles, mais les résidus de son extraction seront valorisés soit sous forme de combustible élaboré pour le grignon, soit sous forme d’une base de chimie verte pour les sous-produits du raffinage. D’autres applications sont actuellement à l’étude, car le Maroc à compris, comme tous les autres grands pays producteurs, que l’olive était un nouveau gisement de richesses.

  13. Study of Au+Au relativistic collisions with the Fopi-Phase I detector; Etude des collisions relativistes Au+Au avec le detecteur Fopi-Phase I

    Energy Technology Data Exchange (ETDEWEB)

    Dupieux, P.

    1995-01-01

    Au+Au relativistic collisions, in a 100-1000 MeV energy domain per nucleon, are described. Experiments have been carried out with the SIS accelerator at GSI/Darmstadt. Data are analysed with the FOPI-phase I detector. These data are compared with IQMD model (Isospin Quantum Molecular Dynamics) Predictions. (S.G). 80 refs., 77 figs., 5 tabs.

  14. English for au pairs the au pair's guide to learning English

    CERN Document Server

    Curtis, Lucy

    2014-01-01

    English for Au Pairs has interlinked stories about a group of au pairs new to England. Marta, an 18-year-old from Poland arrives in the UK to work as an au pair. Throughout her year-long stay she has many different experiences - some bad, some good - but with the support of her host family she finds new friends and improves her English. English for Au Pairs offers insight into the joys and difficulties of being an au pair while at the same time reinforcing English language learning through grammar explanations and exercises.

  15. Antiproton Production in Au+Au Collisions at 11.7a GeV/c

    International Nuclear Information System (INIS)

    Antiproton production in 11.7A GeV/c Au+Au collisions over a wide transverse-mass coverage was studied using the AGS-E866 experimental apparatus. The mean transverse kinetic energy increases as a function of centrality and is similar to that of protons. The antiproton yields in Si+Al , Si+Au , and Au+Au collisions are consistent with scaling with the 0.7 power of the number of participant nucleons. Copyright 1998, The American Physical Society

  16. AU-EU “Strategic Partnership”

    DEFF Research Database (Denmark)

    Rodt, Annemarie Peen; Okeke, Jide

    2013-01-01

    This article appraises strategic partnership between the African Union (AU) and European Union (EU). It examines the context and nature of AU and EU security relations and explores the conditions under which partnership has a positive impact in this regard. This includes an evaluation of converge......This article appraises strategic partnership between the African Union (AU) and European Union (EU). It examines the context and nature of AU and EU security relations and explores the conditions under which partnership has a positive impact in this regard. This includes an evaluation...... of convergence between the two organizations and its effect or lack thereof on African security. The article concludes that events leading up to and initiatives following the 2007 Joint Africa–European Union Strategy have produced a degree of AU and EU convergence, which has had limited impact on the efficacy...

  17. Strain distributions of confined Au/Ag and Ag/Au nanoparticles

    Institute of Scientific and Technical Information of China (English)

    黄红华; 章英; 刘晓山; 骆兴芳; 袁彩雷; 叶双莉

    2015-01-01

    The strain distributions of Au/Ag and Ag/Au nanoparticles confined in the Al2O3 matrix with different core sizes are investigated by using the finite element method, respectively. The simulation results clearly indicate that the compressive strains exerted on the Au/Ag and Ag/Au nanoparticles can be induced by the Al2O3 matrix. Moreover, it can be found that the strain gradient existing in a Au/Ag nanoparticle is much larger than that in a Ag/Au nanoparticle, which could be due to the larger Young’s modulus of Au than that of Ag. With the core size increasing, the strain gradient existing in the Au/Ag nanoparticle becomes larger, while the strain gradient existing in the Ag/Au nanoparticle keeps constant. These different strain distributions may have significant infl uences on the structures and morphologies of the Au/Ag and Ag/Au nanoparticles, leading to the different physical properties for potential applications.

  18. Le curriculum scolaire au Chili

    OpenAIRE

    Cox, Cristián

    2012-01-01

    L’article examine l’usage historique du terme « curriculum » au Chili. Il aborde la configuration actuelle de la prescription curriculaire nationale : des « objectifs et contenus minimums », des « programmes d’études », et des « cartes de progrès des apprentissages ». On y décrit les institutions et les processus qui rendent compte de la genèse des définitions curriculaires en vigueur en 2010. Elles sont le résultat de deux étapes de réformes caractérisées par des processus consultatifs et pa...

  19. Des fluides au grand fleuve

    OpenAIRE

    Arrago-Boruah, Émilie

    2016-01-01

    À Guwahati, capitale de l’Assam, le fleuve Brahmapoutre s’inscrit depuis quelques décennies dans le paysage urbain comme un élément essentiellement esthétique. Avant cela, il a été le théâtre de multiples affrontements, comme avec les Moghols au xviie siècle, puis la voie d’acheminement préférée de l’East India Company pour exporter les richesses de la région jusqu’à Calcutta. Pour retracer cette évolution, la lecture d’un texte ancien en sanskrit permet d’établir une comparaison entre le fle...

  20. Portraits de femmes au Biafra

    OpenAIRE

    Ugochukwu, Françoise

    2011-01-01

    Cette étude considère l’impact de la guerre civile nigériane sur la vie quotidienne et les relations interpersonnelles des Biafrais telle qu’elle est présentée dans Femmes en guerre et autres nouvelles d’Achebe et Blow the Fire de Leslie Ofoegbu. Ces deux écrivains, dont l’un, déjà traduit dans plusieurs langues, a été le premier à projeter le pays igbo sur la scène internationale, et dont l’autre est une Écossaise mariée à un Nigérian et qui vécut au Biafra pendant les années de guerre, offr...

  1. Au, Ag and Au:Ag colloidal nanoparticles synthesized by pulsed laser ablation as SERS substrates

    Institute of Scientific and Technical Information of China (English)

    M. Vinod; K.G.Gopchandran

    2014-01-01

    Chemically pure colloidal suspensions of gold and silver nanoparticles were synthesized using pulsed laser ablation. The dependence of laser fluence on the surface plasmon characteristics of the nanoparticles was investigated. Au:Ag colloidal suspensions were prepared by mixing highly monodisperse Au and Ag nanocolloids. The plasmon band of these mixtures was found to be highly sensitive to Au:Ag concentration ratio and wavelength of the laser beam used in the ablation process. The Au:Ag mixture consists of almost spherical shaped nanostructures with a tendency to join with adjacent ones. The surface enhanced Raman scattering activity of the Au, Ag and Au:Ag colloidal suspensions was tested using crystal violet as probe molecules. Enhancement in Raman signal obtained with Au:Ag substrates was found to be promising and strongly depends on its plasmon characteristics.

  2. Au, Ag and Au:Ag colloidal nanoparticles synthesized by pulsed laser ablation as SERS substrates

    Directory of Open Access Journals (Sweden)

    M. Vinod

    2014-12-01

    Full Text Available Chemically pure colloidal suspensions of gold and silver nanoparticles were synthesized using pulsed laser ablation. The dependence of laser fluence on the surface plasmon characteristics of the nanoparticles was investigated. Au:Ag colloidal suspensions were prepared by mixing highly monodisperse Au and Ag nanocolloids. The plasmon band of these mixtures was found to be highly sensitive to Au:Ag concentration ratio and wavelength of the laser beam used in the ablation process. The Au:Ag mixture consists of almost spherical shaped nanostructures with a tendency to join with adjacent ones. The surface enhanced Raman scattering activity of the Au, Ag and Au:Ag colloidal suspensions was tested using crystal violet as probe molecules. Enhancement in Raman signal obtained with Au:Ag substrates was found to be promising and strongly depends on its plasmon characteristics.

  3. Self-assembly of thiolated cyanine aggregates on Au(111) and Au nanoparticle surfaces

    Science.gov (United States)

    Menéndez, Guillermo O.; Cortés, Emiliano; Grumelli, Doris; Méndez de Leo, Lucila P.; Williams, Federico J.; Tognalli, Nicolás G.; Fainstein, Alejandro; Vela, María Elena; Jares-Erijman, Elizabeth A.; Salvarezza, Roberto C.

    2012-01-01

    Heptamethinecyanine J-aggregates display sharp, intense fluorescence emission making them attractive candidates for developing a variety of chem-bio-sensing applications. They have been immobilized on planar thiol-covered Au surfaces and thiol-capped Au nanoparticles by weak molecular interactions. In this work the self-assembly of novel thiolated cyanine (CNN) on Au(111) and citrate-capped AuNPs from solutions containing monomers and J-aggregates has been studied by using STM, XPS, PM-IRRAS, electrochemical techniques and Raman spectroscopy. Data show that CNN species adsorb on the Au surfaces by forming thiolate-Au bonds. We found that the J-aggregates are preferentially adsorbed on the Au(111) surface directly from the solution while adsorbed CNN monomers cannot organize into aggregates on the substrate surface. These results indicate that the CNN-Au interaction is not able to disorganize the large J-aggregates stabilized by π-π stacking to optimize the S-Au binding site but it is strong enough to hinder the π-π stacking when CNNs are chemisorbed as monomers. The optical properties of the J-aggregates remain active after adsorption. The possibility of covalently bonding CNN J-aggregates to Au planar surfaces and Au nanoparticles controlling the J-aggregate/Au distance opens a new path regarding their improved stability and the wide range of biological applications of both CNN and AuNP biocompatible systems.Heptamethinecyanine J-aggregates display sharp, intense fluorescence emission making them attractive candidates for developing a variety of chem-bio-sensing applications. They have been immobilized on planar thiol-covered Au surfaces and thiol-capped Au nanoparticles by weak molecular interactions. In this work the self-assembly of novel thiolated cyanine (CNN) on Au(111) and citrate-capped AuNPs from solutions containing monomers and J-aggregates has been studied by using STM, XPS, PM-IRRAS, electrochemical techniques and Raman spectroscopy. Data show

  4. Controlled Synthesis of Au@AgAu Yolk-Shell Cuboctahedra with Well-Defined Facets.

    Science.gov (United States)

    Londono-Calderon, Alejandra; Bahena, Daniel; Yacaman, Miguel J

    2016-08-01

    The synthesis of Au@AgAu yolk-shell cuboctahedra nanoparticles formed by galvanic replacement in a seed-mediated method is described. Initially, single-crystal Au seeds are used for the formation of Au@Ag core-shell nanocubes, which serve as the template material for the deposition of an external Au layer. The well-controlled synthesis yields the formation of cuboctahedra nanoparticles with smooth inner and outer Au/Ag surfaces. The deposition/oxidation process is described to understand the formation of cuboctahedra and octahedra nanoparticles. The Au core maintains the initial morphology of the seed and remains static at the center of the yolk-shell because of residual Ag. Structural analysis of the shell indicates intrinsic stacking faults (SFs) near the surface. Energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) compositional analysis show an Au-Ag nonordered alloy forming the shell. The three-dimensional structure of the nanoparticles presented open facets on the [111] as observed by electron tomography SIRT reconstruction over a stack of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images. The geometrical model was validated by analyzing the direction of streaks in coherent nanobeam diffraction (NBD). The catalytic activity was evaluated using a model reaction based on the reduction of 4-nitrophenol (4-NTP) by NaBH4 in the presence of Au@AgAu yolk-shell nanoparticles. PMID:27385583

  5. Être notable au Maghreb

    OpenAIRE

    Abouhani, Abdelghani; Amri-Salameh, Nelly; Blili, Leïla; Boubrik, Rahal; Boujarra, Hussein; Cattedra, Raffaele; CATUSSE, Myriam; Cheraï, Ahmed; Ettayeb, Mahmoud; Feneyrol, Olivier; Hénia, Abdelhamid; Jaïdi, Houcine; Kenbib, Mohammed; Khouaja, Ahmed; Lafi, Nora

    2014-01-01

    Le discours dominant dans les pays du Maghreb continue de stigmatiser les figures de notables dits traditionnels au nom de la modernité. L’usage scientifique de la notion de notable n’est pas pour autant disqualifié. Le présent ouvrage s’intéresse au système élitaire au Maghreb sur la longue durée, de l’Antiquité à nos jours. Il en étudie la dynamique en rapport avec les formes historiques du pouvoir et montre comment la notabilité a pris avec le temps des figures changeantes et des nominatio...

  6. Innovation et recomposition territoriale au Maroc

    OpenAIRE

    Boujrouf, Saïd

    2013-01-01

    Introduction Les processus de recomposition territoriale au Maroc se caractérisent par une dynamique continue, reflet des grands changements qui ont affecté les différents secteurs du pays au cours du xxe siècle. Le renouvellement territorial au Maroc est un processus de recomposition permanent, depuis les trames traditionnelles (qu’elles soient tribale, confessionnelle liée aux confréries ou encore « seigneuriale » caïdale) jusqu’aux maillages territoriaux les plus récents en communes et rég...

  7. Au40: A Large Tetrahedral Magic Cluster

    OpenAIRE

    Jiang, De-en; Walter, Michael

    2011-01-01

    40 is a magic number for tetrahedral symmetry predicted in both nuclear physics and the electronic jellium model. We show that Au40 could be such a a magic cluster from density functional theory-based basin hopping for global minimization. The putative global minimum found for Au40 has a twisted pyramid structure, reminiscent of the famous tetrahedral Au20, and a sizable HOMO-LUMO gap of 0.69 eV, indicating its molecular nature. Analysis of the electronic states reveals that the gap is relate...

  8. Au40: A large tetrahedral magic cluster

    Science.gov (United States)

    Jiang, De-En; Walter, Michael

    2011-11-01

    40 is a magic number for tetrahedral symmetry predicted in both nuclear physics and the electronic jellium model. We show that Au40 could be such a a magic cluster from density functional theory-based basin hopping for global minimization. The putative global minimum found for Au40 has a twisted pyramid structure, reminiscent of the famous tetrahedral Au20, and a sizable HOMO-LUMO gap of 0.69 eV, indicating its molecular nature. Analysis of the electronic states reveals that the gap is related to shell closings of the metallic electrons in a tetrahedrally distorted effective potential.

  9. Becoming independent through au pair migration

    DEFF Research Database (Denmark)

    Dalgas, Karina Märcher

    2015-01-01

    article argues that, despite this critique, au pairing does play an important formative role for young Filipinas because it opens up for experiences abroad that enable them to be recognised as independent adults in Philippine society. Rather than autonomy, however, au pairs define their independence in...... terms of their capacity to assume responsibility for others, thereby achieving a position of social respect. Based on ethnographic fieldwork in Denmark and the Philippines, this article explores how young Filipinas use the social, economic, and cultural resources they gain from their au pair stay abroad...

  10. Synthesis of ultrathin face-centered-cubic Au@Pt and Au@Pd core-shell nanoplates from hexagonal-close-packed Au square sheets

    KAUST Repository

    Fan, Zhanxi

    2015-03-17

    The synthesis of ultrathin face-centered-cubic (fcc) Au@Pt rhombic nanoplates is reported through the epitaxial growth of Pt on hexagonal-close-packed (hcp) Au square sheets (AuSSs). The Pt-layer growth results in a hcp-to-fcc phase transformation of the AuSSs under ambient conditions. Interestingly, the obtained fcc Au@Pt rhombic nanoplates demonstrate a unique (101)f orientation with the same atomic arrangement extending from the Au core to the Pt shell. Importantly, this method can be extended to the epitaxial growth of Pd on hcp AuSSs, resulting in the unprecedented formation of fcc Au@Pd rhombic nanoplates with (101)f orientation. Additionally, a small amount of fcc (100)f-oriented Au@Pt and Au@Pd square nanoplates are obtained with the Au@Pt and Au@Pd rhombic nanoplates, respectively. We believe that these findings will shed new light on the synthesis of novel noble bimetallic nanostructures. Phase change: Ultrathin Au@Pt and Au@Pd core-shell nanoplates were prepared from Au square sheets. A phase transformation from hexagonal close-packed (hcp) to face-centered cubic (fcc) is observed upon coating the hcp Au square sheets with Pt or Pd under ambient conditions. The prepared fcc Au@Pt and Au@Pd rhombic nanoplates demonstrate unique (101)f orientation (picture shows a typical fcc Au@Pt rhombic nanoplate). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Et pourquoi pas au CERN ?

    CERN Multimedia

    Staff Association

    2015-01-01

    Télétravail ou travail à distance, aménagement des horaires de travail et autres évolutions favorables à un meilleur équilibre vie privée et vie professionnelle sont adoptés par nombre d’entreprises et d’organisations !   Rendu possible grâce au développement de nouvelles technologies dont Internet, le travail à distance séduit de plus en plus de personnels, ainsi que de plus en plus de sociétés qui y trouvent des avantages en matière de gestion de l’espace, de sécurité (moins de trajets domicile-entreprise), de développement durable (moins de pollution), de motivation et de bien-être de leurs personnels. Les horaires aménagés, voire les « core-hours1 », sont également des pratiques de plus e...

  12. Studying of the photoluminescence characteristics of Au(0)@Au(I)-thiolate core–shell nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Lu; Zhang, Liquan; Wang, Yinghui, E-mail: yinghui-wang@jlu.edu.cn; Yuan, Qilin; Liu, Qinghui [Jilin University, Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics (China); Wang, Yu [Jilin University, State Key Laboratory on Integrated Optoelectronics, and College of Electronic Science and Engineering (China); Sui, Ning; Kang, Zhihui [Jilin University, Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics (China); Liu, Wenyan; Yu, William W.; Zhang, Yu, E-mail: yuzhang@jlu.edu.cn [Jilin University, State Key Laboratory on Integrated Optoelectronics, and College of Electronic Science and Engineering (China); Li, Xuecong [Tianjin Polytechnic University, School of Science (China); Zhang, Hanzhuang, E-mail: zhanghz@jlu.edu.cn [Jilin University, Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics (China)

    2015-12-15

    The photoluminescence characteristics of Au(0)@Au(I)-thiolate Core–shell nanoclusters (Au-NCs), whose size is <2 nm, are investigated. We use the time-resolved single-photon counting technique and the transient absorption technique to distinguish the mechanism of the photoluminescence of Au-NCs. The dynamic spectral data show that the photoluminescence mechanism should be composed of the fluorescence and the phosphorescence. Meanwhile, Au-NCs have the aggregation induced photoluminescence enhancement property, which is attributed to the suppression of conversion from the singlet state to triplet state when they aggregated together. In addition, the photoluminescence characteristics of aggregated Au-NCs should be further improved through infiltrating them into photonic crystals.

  13. A comparative study of Ge/Au/Ni/Au-based ohmic contact on graphene

    International Nuclear Information System (INIS)

    Superior graphene—metal contacts can improve the performance of graphene devices. We report on an experimental demonstration of Ge/Au/Ni/Au-based ohmic contact on graphene. The transfer length method (TLM) is adopted to measure the resistivity of graphene-metal contacts. We designed a process flow, which can avoid residual photoresist at the interface of metal and graphene. Additionally, rapid thermal annealing (RTA) at different temperatures as a post-processing method is studied to improve graphene—metal contact. The results reveal that the contact resistivity of graphene and Ge/Au/Ni/Au can reach 10−5 Ω·cm2 after RTA, and that 350 °C is optimum annealing temperature for the contact of graphene—Ge/Au/Ni/Au. This paper provides guidance for fabrication and applications of graphene devices. (semiconductor technology)

  14. Studying of the photoluminescence characteristics of Au(0)@Au(I)-thiolate core–shell nanoclusters

    International Nuclear Information System (INIS)

    The photoluminescence characteristics of Au(0)@Au(I)-thiolate Core–shell nanoclusters (Au-NCs), whose size is <2 nm, are investigated. We use the time-resolved single-photon counting technique and the transient absorption technique to distinguish the mechanism of the photoluminescence of Au-NCs. The dynamic spectral data show that the photoluminescence mechanism should be composed of the fluorescence and the phosphorescence. Meanwhile, Au-NCs have the aggregation induced photoluminescence enhancement property, which is attributed to the suppression of conversion from the singlet state to triplet state when they aggregated together. In addition, the photoluminescence characteristics of aggregated Au-NCs should be further improved through infiltrating them into photonic crystals

  15. Charged hadron transverse momentum distributions in Au+Au collisions at S=200 GeV

    Science.gov (United States)

    Roland, Christof; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, 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.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2003-03-01

    We present transverse momentum distributions of charged hadrons produced in Au+Au collisions at sqrt(s_NN) = 200 GeV. The evolution of the spectra for transverse momenta p_T from 0.25 to 5GeV/c is studied as a function of collision centrality over a range from 65 to 344 participating nucleons. We find a significant change of the spectral shape between proton-antiproton and peripheral Au+Au collisions. Comparing peripheral to central Au+Au collisions, we find that the yields at the highest p_T exhibit approximate scaling with the number of participating nucleons, rather than scaling with the number of binary collisions.

  16. Comparative efficiencies of photothermal destruction of malignant cells using antibody-coated silica@Au nanoshells, hollow Au/Ag nanospheres and Au nanorods

    Science.gov (United States)

    Cheng, Fong-Yu; Chen, Chen-Tai; Yeh, Chen-Sheng

    2009-10-01

    Three Au-based nanomaterials (silica@Au nanoshells, hollow Au/Ag nanospheres and Au nanorods) were evaluated for their comparative photothermal efficiencies at killing three types of malignant cells (A549 lung cancer cells, HeLa cervix cancer cells and TCC bladder cancer cells) using a CW NIR laser. Photodestructive efficiency was evaluated as a function of the number of nanoparticles required to destroy the cancer cells under 808 nm laser wavelength at fixed laser power. Of the three nanomaterials, silica@Au nanoshells needed the minimum number of particles to produce effective photodestruction, whereas Au nanorods needed the largest number of particles. Together with the calculated photothermal conversion efficiency, the photothermal efficiency rankings are silica@Au nanoshells > hollow Au/Ag nanospheres > Au nanorods. Additionally, we found that HeLa cells seem to present better heat tolerance than the other two cancer cell lines.

  17. Electrical conduction through self-assembled monolayers in molecular junctions: Au/molecules/Au versus Au/molecule/PEDOT:PSS/Au

    International Nuclear Information System (INIS)

    We fabricated and characterized a large number of octanedithiol (denoted as DC8) molecular devices as vertical metal-molecule-metal structure with or without using an intermediate conducting polymer layer of poly (3,4-ethylenedioxythiophene) stabilized with poly(4-styenesulfonic acid) (called as PEDOT:PSS). The electronic transport properties of DC8 molecular devices with and without PEDOT:PSS layer were statistically compared in terms of current density and device yield. The yields of the working molecular devices were found to be ∼ 1.75% (84 out of 4800 devices) for Au/DC8/Au junctions and ∼ 58% (74 out of 128 devices) for Au-DC8/PEDOT:PSS/Au junctions. The tunneling decay constants were obtained with the Simmons tunneling model and a multibarrier tunneling model for two kinds of molecular devices with and without PEDOT:PSS layer.

  18. Proton channeling in Au at low energies

    International Nuclear Information System (INIS)

    The electronic energy loss for low velocity protons channeled in the direction single crystal Au is calculated. The spatial distribution of valence electronic density in Au is calculated using Tight Binding Linear Muffin Tin Method. The proton trajectories are determined by numerical integration of the classical motion equation, and the energy loss is evaluated using the calculated valence electronic density in the friction term. The results allow to describe qualitatively the non linear behavior of energy loss with ion velocity observed experimentally. (author)

  19. Electrochemical Characterization of Protein Adsorption onto YNGRT-Au and VLGXE-Au Surfaces

    OpenAIRE

    Hanna Trzeciakiewicz; Jose Esteves-Villanueva; Rania Soudy; Kamaljit Kaur; Sanela Martic-Milne

    2015-01-01

    The adsorption of the proteins CD13, mucin and bovine serum albumin on VLGXE-Au and YNGRT-Au interfaces was monitored by electrochemical impedance spectroscopy in the presence of [Fe(CN)6]3−/4−. The hydrophobicity of the Au surface was tailored using specific peptides, blocking agents and diluents. The combination of blocking agents (ethanolamine or n-butylamine) and diluents (hexanethiol or 2-mercaptoethanol) was used to prepare various peptide-modified Au surfaces. Protein adsorption onto t...

  20. Apprentissages techniques : L'apprentissage au CERN

    CERN Multimedia

    2004-01-01

    APPRENTISSAGES TECHNIQUES GESTION ET DEVELOPPEMENT DU PERSONNEL HR/PMD L'APPRENTISSAGE AU CERN 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). 7 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 9ème du Cycle d'orientation genevois (3ème en France) • être ressortissant d'un pays membre du CERN (Allemagne, Autriche, Belgiqu...

  1. Evidence of final-state suppression of high-p{_ T} hadrons in Au + Au collisions using d + Au measurements at RHIC

    Science.gov (United States)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Veres, G. I.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wysłouch, B.; Zhang, J.

    Transverse momentum spectra of charged hadrons with pT 2 GeV/c). In contrast, the d + Au nuclear modification factor exhibits no suppression of the high-pT yields. These measurements suggest a large energy loss of the high-pT particles in the highly interacting medium created in the central Au + Au collisions. The lack of suppression in d + Au collisions suggests that it is unlikely that initial state effects can explain the suppression in the central Au + Au collisions. PACS: 25.75.-q

  2. Systematic measurements of identified particle spectra in pp, d+Au, and Au+Au collisions at the STAR detector

    Science.gov (United States)

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Averichev, G. S.; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Baumgart, S.; Beavis, D. R.; Bellwied, R.; Benedosso, F.; Betts, R. R.; Bhardwaj, S.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Biritz, B.; Bland, L. C.; Bombara, M.; Bonner, B. E.; Botje, M.; Bouchet, J.; Braidot, E.; Brandin, A. V.; Bruna, E.; Bueltmann, S.; Burton, T. P.; Bystersky, M.; Cai, X. Z.; Caines, H.; Sánchez, M. Calderón De La Barca; Callner, J.; Catu, O.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, K. E.; Christie, W.; Chung, S. U.; Clarke, R. F.; Codrington, M. J. M.; Coffin, J. P.; Cormier, T. M.; Cosentino, M. R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Daugherity, M.; Silva, C. De; Dedovich, T. G.; Dephillips, M.; Derevschikov, A. A.; de Souza, R. Derradi; Didenko, L.; Djawotho, P.; Dogra, S. M.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, F.; Dunlop, J. C.; Mazumdar, M. R. Dutta; Edwards, W. R.; Efimov, L. G.; Elhalhuli, E.; Elnimr, M.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Eun, L.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Feng, A.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Gagliardi, C. A.; Gaillard, L.; Gangadharan, D. R.; Ganti, M. S.; Garcia-Solis, E.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y. N.; Gordon, A.; Grebenyuk, O.; Grosnick, D.; Grube, B.; Guertin, S. M.; Guimaraes, K. S. F. F.; Gupta, A.; Gupta, N.; Guryn, W.; Haag, B.; Hallman, T. J.; Hamed, A.; Harris, J. W.; He, W.; Heinz, M.; Heppelmann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffman, A. M.; Hoffmann, G. W.; Hofman, D. J.; Hollis, R. S.; Huang, H. Z.; Humanic, T. J.; Igo, G.; Iordanova, A.; Jacobs, P.; Jacobs, W. W.; Jakl, P.; Jin, F.; Jones, P. G.; Joseph, J.; Judd, E. G.; Kabana, S.; Kajimoto, K.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Kettler, D.; Khodyrev, V. Yu.; Kiryluk, J.; Kisiel, A.; Klein, S. R.; Knospe, A. G.; Kocoloski, A.; Koetke, D. D.; Kopytine, M.; Kotchenda, L.; Kouchpil, V.; Kravtsov, P.; Kravtsov, V. I.; Krueger, K.; Krus, M.; Kuhn, C.; Kumar, L.; Kurnadi, P.; Lamont, M. A. C.; Landgraf, J. M.; Lapointe, S.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C.-H.; Levine, M. J.; Li, C.; Li, Y.; Lin, G.; Lin, X.; Lindenbaum, S. J.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Love, W. A.; Lu, Y.; Ludlam, T.; Lynn, D.; Ma, G. L.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Mall, O. I.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Matis, H. S.; Matulenko, Yu. A.; McShane, T. S.; Meschanin, A.; Millane, J.; Miller, M. L.; Minaev, N. G.; Mioduszewski, S.; Mischke, A.; Mitchell, J.; Mohanty, B.; Molnar, L.; Morozov, D. A.; Munhoz, M. G.; Nandi, B. K.; Nattrass, C.; Nayak, T. K.; Nelson, J. M.; Nepali, C.; Netrakanti, P. K.; Ng, M. J.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Okada, H.; Okorokov, V.; Olson, D.; Pachr, M.; Page, B. S.; Pal, S. K.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S. C.; Planinic, M.; Pluta, J.; Poljak, N.; Poskanzer, A. M.; Potukuchi, B. V. K. S.; Prindle, D.; Pruneau, C.; Pruthi, N. K.; Putschke, J.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Reed, R.; Ridiger, A.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M. J.; Rykov, V.; Sahoo, R.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sarsour, M.; Schambach, J.; Scharenberg, R. P.; Schmitz, N.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shabetai, A.; Shahaliev, E.; Shao, M.; Sharma, M.; Shi, S. S.; Shi, X.-H.; Sichtermann, E. P.; Simon, F.; Singaraju, R. N.; Skoby, M. J.; Smirnov, N.; Snellings, R.; Sorensen, P.; Sowinski, J.; Spinka, H. M.; Srivastava, B.; Stadnik, A.; Stanislaus, T. D. S.; Staszak, D.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Subba, N. L.; Sumbera, M.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Symons, T. J. M.; de Toledo, A. Szanto; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Thein, D.; Thomas, J. H.; Tian, J.; Timmins, A. R.; Timoshenko, S.; Tlusty, D.; Tokarev, M.; Tram, V. N.; Trattner, A. L.; Trentalange, S.; Tribble, R. E.; Tsai, O. D.; Ulery, J.; Ullrich, T.; Underwood, D. G.; Buren, G. Van; van Leeuwen, M.; Molen, A. M. Vander; Vanfossen, J. A., Jr.; Varma, R.; Vasconcelos, G. M. S.; Vasilevski, I. M.; Vasiliev, A. N.; Videbaek, F.; Vigdor, S. E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Wada, M.; Waggoner, W. T.; Wang, F.; Wang, G.; Wang, J. S.; Wang, Q.; Wang, X.; Wang, X. L.; Wang, Y.; Webb, J. C.; Westfall, G. D.; Whitten, C., Jr.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xu, N.; Xu, Q. H.; Xu, Y.; Xu, Z.; Yepes, P.; Yoo, I.-K.; Yue, Q.; Zawisza, M.; Zbroszczyk, H.; Zhan, W.; Zhang, H.; Zhang, S.; Zhang, W. M.; Zhang, Y.; Zhang, Z. P.; Zhao, Y.; Zhong, C.; Zhou, J.; Zoulkarneev, R.; Zoulkarneeva, Y.; Zuo, J. X.

    2009-03-01

    Identified charged-particle spectra of π±, K±, p, and pmacr at midrapidity (|y|<0.1) measured by the dE/dx method in the STAR (solenoidal tracker at the BNL Relativistic Heavy Ion Collider) time projection chamber are reported for pp and d+Au collisions at sNN=200 GeV and for Au+Au collisions at 62.4, 130, and 200 GeV. Average transverse momenta, total particle production, particle yield ratios, strangeness, and baryon production rates are investigated as a function of the collision system and centrality. The transverse momentum spectra are found to be flatter for heavy particles than for light particles in all collision systems; the effect is more prominent for more central collisions. The extracted average transverse momentum of each particle species follows a trend determined by the total charged-particle multiplicity density. The Bjorken energy density estimate is at least several GeV/fm3 for a formation time less than 1 fm/c. A significantly larger net-baryon density and a stronger increase of the net-baryon density with centrality are found in Au+Au collisions at 62.4 GeV than at the two higher energies. Antibaryon production relative to total particle multiplicity is found to be constant over centrality, but increases with the collision energy. Strangeness production relative to total particle multiplicity is similar at the three measured RHIC energies. Relative strangeness production increases quickly with centrality in peripheral Au+Au collisions, to a value about 50% above the pp value, and remains rather constant in more central collisions. Bulk freeze-out properties are extracted from thermal equilibrium model and hydrodynamics-motivated blast-wave model fits to the data. Resonance decays are found to have little effect on the extracted kinetic freeze-out parameters because of the transverse momentum range of our measurements. The extracted chemical freeze-out temperature is constant, independent of collision system or centrality; its value is close

  3. Au-Pt alloy nanocrystals incorporated in silica films

    OpenAIRE

    Goutam De; Rao, CNR

    2005-01-01

    Au, Pt and Au-Pt alloy nanocrystals have been prepared in thin SiO2 film matrices by sol-gel spin-coating, followed by heating at 450 uC in 10% $H_{2}$-90% Ar. X-Ray diffraction patterns reveal that the Au and Au-Pt nanocrystals have a preferential (111) orientation. Upon increasing the Pt concentration, part of the Pt does not alloy with Au, but instead forms a shell around the Au-Pt alloy core. The alloy composition itself goes up to Au(50) : Pt(50), and the Pt shells are formed around the ...

  4. XAFS studies of Au nanocrystals passivated by different surfactants

    International Nuclear Information System (INIS)

    The electronic and atomic structures of Au nanocrystals affected by different surfactants (PPh3, PVP, and dodecanethiol) capping were studied by X-ray absorption fine structure (XAFS) at Au L3-edge. For PPh3, PVP, and dodecanethiol-capped Au nanocrystals, the surface Au atoms interact with P, O, and S atoms respectively; however, only for dodecanethiol-capped Au nanocrystals, a significant electron transfer between Au and S atoms is observed. The extend-XAFS results reveal that the atomic structure disorder of Au-Au shell gradually increases from 0.0095 to 0.0152 Å2 when the surfactants goes from PPh3 to dodecanethiol. These results suggest that the surfactants would change the electronic and atomic structures of Au nanocrystals rather than merely passivates on the surface of Au nanocrystals.

  5. Suppression of ϒ production in d+Au and Au+Au collisions at √(sNN)=200 GeV

    International Nuclear Information System (INIS)

    We report measurements of ϒ meson production in p+p, d+Au, and Au+Au collisions using the STAR detector at RHIC. We compare the ϒ yield to the measured cross section in p+p collisions in order to quantify any modifications of the yield in cold nuclear matter using d+Au data and in hot nuclear matter using Au+Au data separated into three centrality classes. Our p+p measurement is based on three times the statistics of our previous result. We obtain a nuclear modification factor for ϒ(1S+2S+3S) in the rapidity range |y|<1 in d+Au collisions of RdAu=0.79±0.24(stat.)±0.03(syst.)±0.10(p+p syst.). A comparison with models including shadowing and initial state parton energy loss indicates the presence of additional cold-nuclear matter suppression. Similarly, in the top 10% most-central Au+Au collisions, we measure a nuclear modification factor of RAA=0.49±0.1(stat.)±0.02(syst.)±0.06(p+psyst.), which is a larger suppression factor than that seen in cold nuclear matter. Our results are consistent with complete suppression of excited-state ϒ mesons in Au+Au collisions. The additional suppression in Au+Au is consistent with the level expected in model calculations that include the presence of a hot, deconfined Quark–Gluon Plasma. However, understanding the suppression seen in d+Au is still needed before any definitive statements about the nature of the suppression in Au+Au can be made

  6. Charged particle density distributions in Au + Au collisions at relativistic heavy-ion collider energies

    Indian Academy of Sciences (India)

    Fauad Rami

    2003-05-01

    Charged particle pseudorapidity distributions have been 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.

  7. Using supported Au nanoparticles as starting material for preparing uniform Au/Pd bimetallic catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Villa, Alberto [Universita di Milano, Italy; Prati, Laura [Universita di Milano, Italy; Su, Dangshen [Fritz Haber Institute of the Max Planck Society, Berlin, Germany; Wang, Di [Fritz Haber Institute of the Max Planck Society, Berlin, Germany; Veith, Gabriel M [ORNL

    2010-01-01

    One of the best methods for producing bulk homogeneous (composition) supported bimetallic AuPd clusters involves the immobilization of a protected Au seed followed by the addition of Pd. This paper investigates the importance of this gold seed in controlling the resulting bimetallic AuPd clusters structures, sizes and catalytic activities by investigating three different gold seeds. Uniform Au-Pd alloy were obtained when a steric/electrostatic protecting group, poly(vinyl alcohol) (PVA), was used to form the gold clusters on activated carbon (AC). In contrast Au/AC precursors prepared using Au nanoparticles with only electrostatic stabilization (tetrakis(hydroxypropyl)phosphonium chloride (THPC)), or no stabilization (magnetron sputtering) produced inhomogeneous alloys and segregation of the gold and palladium. The uniform alloyed catalyst (Pd{at}Au{sub PVA}/AC) is the most active and selective catalyst, while the inhomogenous catalysts are less active and selective. Further study of the PVA protected Au clusters revealed that the amount of PVA used is also critical for the preparation of uniform alloyed catalyst, their stability, and their catalytic activity.

  8. Electrochemical Characterization of Protein Adsorption onto YNGRT-Au and VLGXE-Au Surfaces

    Directory of Open Access Journals (Sweden)

    Hanna Trzeciakiewicz

    2015-08-01

    Full Text Available The adsorption of the proteins CD13, mucin and bovine serum albumin on VLGXE-Au and YNGRT-Au interfaces was monitored by electrochemical impedance spectroscopy in the presence of [Fe(CN6]3−/4−. The hydrophobicity of the Au surface was tailored using specific peptides, blocking agents and diluents. The combination of blocking agents (ethanolamine or n-butylamine and diluents (hexanethiol or 2-mercaptoethanol was used to prepare various peptide-modified Au surfaces. Protein adsorption onto the peptide-Au surfaces modified with the combination of n-butylamine and hexanethiol produced a dramatic decrease in the charge transfer resistance, Rct, for all three proteins. In contrast, polar peptide-surfaces induced a minimal change in Rct for all three proteins. Furthermore, an increase in Rct was observed with CD13 (an aminopeptidase overexpressed in certain cancers in comparison to the other proteins when the VLGXE-Au surface was modified with n-butylamine as a blocking agent. The electrochemical data indicated that protein adsorption may be modulated by tailoring the peptide sequence on Au surfaces and that blocking agents and diluents play a key role in promoting or preventing protein adsorption. The peptide-Au platform may also be used for targeting cancer biomarkers with designer peptides.

  9. Electrochemical Characterization of Protein Adsorption onto YNGRT-Au and VLGXE-Au Surfaces.

    Science.gov (United States)

    Trzeciakiewicz, Hanna; Esteves-Villanueva, Jose; Soudy, Rania; Kaur, Kamaljit; Martic-Milne, Sanela

    2015-01-01

    The adsorption of the proteins CD13, mucin and bovine serum albumin on VLGXE-Au and YNGRT-Au interfaces was monitored by electrochemical impedance spectroscopy in the presence of [Fe(CN)6](3-/4-). The hydrophobicity of the Au surface was tailored using specific peptides, blocking agents and diluents. The combination of blocking agents (ethanolamine or n-butylamine) and diluents (hexanethiol or 2-mercaptoethanol) was used to prepare various peptide-modified Au surfaces. Protein adsorption onto the peptide-Au surfaces modified with the combination of n-butylamine and hexanethiol produced a dramatic decrease in the charge transfer resistance, Rct, for all three proteins. In contrast, polar peptide-surfaces induced a minimal change in Rct for all three proteins. Furthermore, an increase in Rct was observed with CD13 (an aminopeptidase overexpressed in certain cancers) in comparison to the other proteins when the VLGXE-Au surface was modified with n-butylamine as a blocking agent. The electrochemical data indicated that protein adsorption may be modulated by tailoring the peptide sequence on Au surfaces and that blocking agents and diluents play a key role in promoting or preventing protein adsorption. The peptide-Au platform may also be used for targeting cancer biomarkers with designer peptides. PMID:26262621

  10. Au+Au reactions at the AGS: Experiments E866 and E917

    Energy Technology Data Exchange (ETDEWEB)

    Ogilvie, C.A.; Ahle, L. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Physics; Akiba, Y. [KEK, Tanashi (Japan)] [and others; E866 Collaboration; E917 Collaboration

    1997-12-01

    Particle production and correlation functions from Au+Au reactions have been measured as a function of both beam energy (2--10.7 AGeV) and impact parameter. These results are used to probe the dynamics of heavy-ion reactions, confront hadronic models over a wide range of conditions and to search for the onset of new phenomena.

  11. Study of Au+Au relativistic collisions with the Fopi-Phase I detector

    International Nuclear Information System (INIS)

    Au+Au relativistic collisions, in a 100-1000 MeV energy domain per nucleon, are described. Experiments have been carried out with the SIS accelerator at GSI/Darmstadt. Data are analysed with the FOPI-phase I detector. These data are compared with IQMD model (Isospin Quantum Molecular Dynamics) Predictions. (S.G). 80 refs., 77 figs., 5 tabs

  12. Λ production in AuAu collisions at 11.6 GeV/c

    International Nuclear Information System (INIS)

    I present the first measurement at AGS energies of the rapidity and transverse mass distributions for A production with Au beam on Au target. The measurements cover the rapidity region of 2.0 to 3.2 and transverse momenta of 0.0 to 1.4 GeV/c. The results are compared with the predictions of two models

  13. Identified particles in Au+Au collisions at S=200 GeV

    Science.gov (United States)

    Phobos Collaboration; Wosiek, Barbara; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Manly, S.; McLeod, D.; Michałowski, 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.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2003-03-01

    The yields of identified particles have been measured at RHIC for Au+Au collisions at S=200 GeV using the PHOBOS spectrometer. The ratios of antiparticle to particle yields near mid-rapidity are presented. The first measurements of the invariant yields of charged pions, kaons and protons at very low transverse momenta are also shown.

  14. Strangelet search in Au+Au collisions at VsNN=200 GeV

    NARCIS (Netherlands)

    Bai, Y.; Benedosso, F.; Botje, M.A.J.; Grebenyuk, O.; Mischke, A.; Peitzmann, T.; Russcher, M.J.; Snellings, R.J.M.; van der Kolk, N.

    2007-01-01

    We have searched for strangelets in a triggered sample of 61 million central (top 4%) Au+Au collisions at √sNN=200 GeV near beam rapidities at the STAR solenoidal tracker detector at the BNL Relativistic Heavy Ion Collider. We have sensitivity to metastable strangelets with lifetimes of order ⩾0.1 n

  15. First steps of ion beam mixing: study by X-ray reflectometry and neutron diffraction; Premieres etapes du melange par faisceau d`ions: etude par reflectometrie de rayons X et diffraction de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Le Boite, M.G.

    1987-12-01

    There are several processes involved in ion beam mixing: ballistic processes, chemical driving forces and radiation enhanced diffusion. Experiments usually performed on bilayers irradiated with heavy elements and characterized by Rutherford backscattering (R.B.S.), have shown that the measured mixing rate is always higher than the calculated one, taking into account ballistic effects only. Besides classical R.B.S. experiments on NiAu and NiPt bilayers irradiated with Xe, we have used another technique of characterization: X-ray reflectometry and neutron diffraction, performed on multilayers irradiated with He. The systems are NiAu, NiPt, NiPd and NiAg, which behave similarly from the ballistic point of view, but have very different heats of mixing. In these experiments, the range of deposited energy density is very low, in contrast to heavy ions irradiation: this has allowed us to reach very low diffusion coefficent, never observed before. The dependence of the diffusion coefficient on the heat of mixing is in agreement with the one theoretically calculated. For the NiAg system, which has a positive heat of mixing, the measured diffusion coefficient is smaller than the ballistic one: a decrease of the ballistic mixing rate is seen for the first time. In this work, we have shown the interest of the reflectometry techniques (X-ray and neutrons); we have used a simple model to analyze the ion beam mixing, when elementary processes are involved.

  16. Jets and dijets in Au+Au and p+p collisions at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Hardtke, D.; STAR Collaboration

    2002-12-09

    Recent data from RHIC suggest novel nuclear effects in the production of high p{sub T} hadrons. We present results from the STAR detector on high p{sub T} angular correlations in Au+Au and p+p collisions at {radical}S = 200 GeV/c. These two-particle angular correlation measurements verify the presence of a partonic hard scattering and fragmentation component at high p{sub T} in both central and peripheral Au+Au collisions. When triggering on a leading hadron with p{sub T}>4 GeV, we observe a quantitative agreement between the jet cone properties in p+p and all centralities of Au+Au collisions. This quantitative agreement indicates that nearly all hadrons with p{sub T}>4 GeV/c come from jet fragmentation and that jet fragmentation properties are not substantially modified in Au+Au collisions. STAR has also measured the strength of back-to-back high p{sub T} charged hadron correlations, and observes a small suppression of the back-to-back correlation strength in peripheral collisions, and a nearly complete disappearance o f back-to-back correlations in central Au+Au events. These phenomena, together with the observed strong suppression of inclusive yields and large value of elliptic flow at high p{sub T}, are consistent with a model where high p{sub T} hadrons come from partons created near the surface of the collision region, and where partons that originate or propagate towards the center of the collision region are substantially slowed or completely absorbed.

  17. Spectra and ratios of identified particles in Au+Au and d+Au collisions at sqrt(s_NN)=200 GeV

    CERN Document Server

    Adare, A; Aidala, C; Ajitanand, N N; Akiba, Y; Al-Bataineh, H; Alexander, J; Angerami, A; Aoki, K; Apadula, N; Aramaki, Y; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Baksay, G; Baksay, L; Barish, K N; Bassalleck, B; Basye, A T; Bathe, S; Baublis, V; Baumann, C; Bazilevsky, A; Belikov, S; Belmont, R; Bennett, R; Berdnikov, A; Berdnikov, Y; Bhom, J H; Bickley, A A; Blau, D S; Bok, J S; Boyle, K; Brooks, M L; Buesching, H; Bumazhnov, V; Bunce, G; Butsyk, S; Camacho, C M; Campbell, S; Caringi, A; Chen, C -H; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choudhury, R K; Christiansen, P; Chujo, T; Chung, P; Chvala, O; Cianciolo, V; Citron, Z; Cole, B A; del Valle, Z Conesa; Connors, M; Constantin, P; Csanád, M; Csörgő, T; Dahms, T; Dairaku, S; Danchev, I; Das, K; Datta, A; David, G; Dayananda, M K; Denisov, A; Deshpande, A; Desmond, E J; Dharmawardane, K V; Dietzsch, O; Dion, A; Donadelli, M; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; Dutta, D; D'Orazio, L; Edwards, S; Efremenko, Y V; Ellinghaus, F; Engelmore, T; Enokizono, A; En'yo, H; Esumi, S; Fadem, B; 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; Garishvili, I; Glenn, A; Gong, H; Gonin, M; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Grim, G; Perdekamp, M Grosse; Gunji, T; Gustafsson, H -Å; Haggerty, J S; Hahn, K I; Hamagaki, H; Hamblen, J; Han, R; Hanks, J; Hartouni, E P; Haslum, E; Hayano, R; He, X; Heffner, M; Hemmick, T K; Hester, T; Hill, J C; Hohlmann, M; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hornback, D; Huang, S; Ichihara, T; Ichimiya, R; Ide, J; Ikeda, Y; Imai, K; Inaba, M; Isenhower, D; Ishihara, M; Isobe, T; Issah, M; Isupov, A; Ivanischev, D; Iwanaga, Y; Jacak, B V; Jia, J; Jiang, X; Jin, J; Johnson, B M; Jones, T; Joo, K S; Jouan, D; Jumper, D S; Kajihara, F; Kametani, S; Kamihara, N; Kamin, J; Kang, J H; Kapustinsky, J; Karatsu, K; Kasai, M; Kawall, D; Kawashima, M; Kazantsev, A V; Kempel, T; Khanzadeev, A; Kijima, K M; Kikuchi, J; Kim, A; Kim, B I; Kim, D H; Kim, D J; Kim, E; Kim, E -J; Kim, S H; Kim, Y -J; Kim, Y J; Kinney, E; Kiriluk, K; Kiss, Á; Kistenev, E; Kleinjan, D; Kochenda, L; Komkov, B; Konno, M; Koster, J; Kotchetkov, D; Kozlov, A; Král, A; Kravitz, A; 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, J; Lee, K; Lee, K B; Lee, K S; Leitch, M J; Leite, M A L; Leitner, E; Lenzi, B; Li, X; Lichtenwalner, P; Liebing, P; Levy, L A Linden; Liška, T; Litvinenko, A; Liu, H; Liu, M X; Love, B; Luechtenborg, R; Lynch, D; Maguire, C F; Makdisi, Y I; Malakhov, A; Malik, M D; Manko, V I; Mannel, E; Mao, Y; Masui, H; Matathias, F; McCumber, M; McGaughey, P L; McGlinchey, D; Means, N; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Mikeš, P; Miki, K; Milov, A; Mishra, M; Mitchell, J T; Mohanty, A K; Moon, H J; Morino, Y; Morreale, A; Morrison, D P; Moukhanova, T V; Murakami, T; Murata, J; Nagamiya, S; Nagle, J L; Naglis, M; Nagy, M I; Nakagawa, I; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nam, S; Newby, J; Nguyen, M; Nihashi, M; Nouicer, R; Nyanin, A S; Oakley, C; O'Brien, E; Oda, S X; Ogilvie, C A; Oka, M; Okada, K; Onuki, Y; Oskarsson, A; Ouchida, M; Ozawa, K; Pak, R; Pantuev, V; Papavassiliou, V; Park, I H; Park, J; Park, S K; Park, W J; Pate, S F; Pei, H; Peng, J -C; Pereira, H; Peresedov, V; Peressounko, D Yu; Petti, R; Pinkenburg, C; Pisani, R P; Proissl, M; Purschke, M L; Purwar, A K; Qu, H; Rak, J; Rakotozafindrabe, A; Ravinovich, I; Read, K F; Rembeczki, S; Reygers, K; Riabov, V; Riabov, Y; Richardson, E; Roach, D; Roche, G; Rolnick, S D; Rosati, M; Rosen, C A; Rosendahl, S S E; Rosnet, P; Rukoyatkin, P; Ružička, P; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakashita, K; Samsonov, V; Sano, S; Sato, T; Sawada, S; Sedgwick, K; Seele, J; Seidl, R; Semenov, A Yu; Seto, R; Sharma, D; Shein, I; 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; Slunečka, M; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Sparks, N A; Stankus, P W; Stenlund, E; Stoll, S P; Sugitate, T; Sukhanov, A; Sziklai, J; Takagui, E M; 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; Togawa, M; Toia, A; Tomášek, L; Torii, H; Towell, R S; Tserruya, I; Tsuchimoto, Y; Vale, C; Valle, H; van Hecke, H W; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Vinogradov, A A; Virius, M; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Wei, F; Wei, R; Wessels, J; White, S N; Winter, D; Wood, J P; Woody, C L; Wright, R M; Wysocki, M; Xie, W; Yamaguchi, Y L; Yamaura, K; Yang, R; Yanovich, A; Ying, J; Yokkaichi, S; You, Z; Young, G R; Younus, I; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zolin, L

    2013-01-01

    The transverse momentum (p_T) spectra and ratios of identified charged hadrons (\\pi^+/-, K^+/-, p, p^bar) produced in sqrt(s_NN)=200 GeV Au+Au and d+Au collisions are reported in five different centrality classes for each collision species. The measurements of pions and protons are reported up to p_T=6 GeV/c (5 GeV/c), and the measurements of kaons are reported up to p_T=4 GeV/c (3.5 GeV/c) in Au+Au (d+Au) collisions. In the intermediate p_T region, between 2--5 GeV/c, a significant enhancement of baryon to meson ratios compared to those measured in p+p collisions is observed. This enhancement is present in both Au+Au and d+Au collisions, and increases as the collisions become more central. We compare a class of peripheral Au+Au collisions with a class of central d+Au collisions which have a comparable number of participating nucleons and binary nucleon-nucleon collisions. The p_T dependent particle ratios for these classes display a remarkable similarity, which is then discussed.

  18. Rapidity density distributions in Au+Au and Au+Ag interactions at 11.6 A GeV/c

    International Nuclear Information System (INIS)

    Pseudorapidity density distributions of charged particles in heavy-ion collisions have been studied. The results from EMU01 have been compared to the results from the experiments WA80 and E802. The recently obtained pseudorapidity distributions from Au+Au and Au+Ag interactions have been compared to a linear extrapolation from lighter systems. (orig.)

  19. Relative Distribution of Au48+~Au52+ in Au Plasma by Ionization Dynamics

    Institute of Scientific and Technical Information of China (English)

    ZHUZhi-Yan; ZHUZheng-He; JIANGGang

    2003-01-01

    The present work proposes a theoretical method called ionization dynamics to derive the ionic charge state distribution. Using relativistic quantum mechanics to calculate the energy level lifetime and average ionic lifetime of each ion, the first-order ionization rate constant can be obtained. Based on these data, from the solution of differential equations for consecutive-irreversible ionization reactions, one will be able to derive the ionic charge state distribution.The calculated average positive charge 49.24 of Au48+ ~ Au52+ and their relative distribution are in good agreement with the results of Lawrence Livermore National Laboratory.

  20. Polymerase chain reaction of Au nanoparticle-bound primers

    Institute of Scientific and Technical Information of China (English)

    SHEN Hebai; HU Min; YANG Zhongnan; WANG Chen; ZHU Longzhang

    2005-01-01

    Polymerase chain reaction (PCR) is a useful technique for in vitro amplification of a DNA fragment. In this paper, a PCR procedure using Au nanoparticle (AuNP) -bound primers was systemically studied. The 5′-SH- (CH2)6-modified primers were covalently attached to the AuNP surface via Au-S bonds, and plasmid pBluescript SK was used as a template. The effects of the concentration of AuNP-bound primers, annealing temperature and PCR cycles were evaluated, respectively. The results indicate that PCR can proceed successfully under optimized condition, with either forward or reverse primers bound to the AuNP surface or with both the two primers bound to the AuNP surface. Development of PCR procedure based on AuNPs not only makes the isolation of PCR products very convenient, but also provides novel methods to prepare AuNP-bound ssDNA and nanostructured material.

  1. Synthesis and characterization in AuCu–Si nanostructures

    International Nuclear Information System (INIS)

    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 Au2Cu3 and Au3Cu 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 Au3Cu and Au2Cu3 phases. • All alloys present diffusion of Si and Cu through the CuSi alloy formation

  2. 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.

  3. XPS and DFT studies of the electronic structures of AgAuS and Ag3AuS2

    International Nuclear Information System (INIS)

    Highlights: • Photoelectron spectra and DOS were obtained for AgAuS and Ag3AuS2 for the first time. • Essentially higher Au 4f binding energy was found in case of Ag3AuS2. • DFT calculations show a larger overlapping of S 3p and Au 5d valence states for Ag3AuS2. • Energy position of Au 4f levels is mainly influenced by Au–Ag interactions. - Abstract: X-ray photoelectron spectra of core levels and the valence bands were acquired, and the density-of-states (DOS) were calculated using periodic density functional theory (DFT) for synthetic ternary compounds AgAuS and Ag3AuS2, known as minerals petrovskaite uytenbogaardtite, respectively, for the first time. The chemical shift of the Au 4f binding energy as large as 0.65 eV relative to bulk elemental gold was found for Ag3AuS2, in contrast to only about 0.3 eV for AgAuS. The DFT analysis showed, in particular, that the S 3p states are largely pushed out from the Ag 4d and Au 5d bands affording two sub-bands in the valence region of both substances, but the overlapping of the S 3p and Au 5d states is larger for Ag3AuS2. It was demonstrated that the energy position of Au 4f levels is mainly influenced by Au–Ag interaction, and increasing the number of Ag atoms in the first coordination shell of S–Au–S units on going from AgAuS to Ag3AuS2 results in the positive shift of the Au 4f bands consistent with the experimental data

  4. Violence et ordre politique au Nigeria

    OpenAIRE

    Fourchard, Laurent

    2007-01-01

    International audience De nombreuses analyses ont associé le retour d'un régime civil au Nigeria en 1999 au développement d'organisations armées privées et au regain de conflits dits religieux, inter-ethniques ou communautaires. L'application controversée de la charia dans douze Etats du nord et les actions de guérilla dans la région pétrolière du delta ont ainsi largement focalisé l'attention des médias. Le retour de la " démocratie " témoignerait-t-il d'un déclin de l'Etat ? Ces violence...

  5. Au nanoparticles films used in biological sensing

    Energy Technology Data Exchange (ETDEWEB)

    Rosales Perez, M; Delgado Macuil, R; Rojas Lopez, M; Gayou, V L [Centro de Investigacion en BiotecnologIa Aplicada del IPN, Tepetitla Tlaxcala Mexico C.P. 90700 (Mexico); Sanchez Ramirez, J F, E-mail: mrosalespe@ipn.m [CICATA Legaria Instituto Politecnico Nacional, Mexico Distrito Federal (Mexico)

    2009-05-01

    Lactobacillus para paracasei are used commonly as functional food and probiotic substances. In this work Au nanoparticles self-assembled films were used for Lactobacillus para paracasei determination at five different concentrations. Functionalized substrates were immersed in a colloidal solution for one and a half hour at room temperature and dried at room temperature during four hours. After that, drops of Lactobacillus para paracasei in aqueous solution were put into the Au nanoparticles film and let dry at room temperature for another two hours. Infrared spectroscopy in attenuated total reflectance sampling mode was used to observe generation peaks due to substrate silanization, enhancement of Si-O band intensity due to the Au colloids added to silanized substrate and also to observe the enhancement of Lactobacillus para paracasei infrared intensity of the characteristic frequencies at 1650, 1534 and 1450 cm{sup -1} due to surface enhancement infrared absorption.

  6. Au nanoparticles films used in biological sensing

    International Nuclear Information System (INIS)

    Lactobacillus para paracasei are used commonly as functional food and probiotic substances. In this work Au nanoparticles self-assembled films were used for Lactobacillus para paracasei determination at five different concentrations. Functionalized substrates were immersed in a colloidal solution for one and a half hour at room temperature and dried at room temperature during four hours. After that, drops of Lactobacillus para paracasei in aqueous solution were put into the Au nanoparticles film and let dry at room temperature for another two hours. Infrared spectroscopy in attenuated total reflectance sampling mode was used to observe generation peaks due to substrate silanization, enhancement of Si-O band intensity due to the Au colloids added to silanized substrate and also to observe the enhancement of Lactobacillus para paracasei infrared intensity of the characteristic frequencies at 1650, 1534 and 1450 cm-1 due to surface enhancement infrared absorption.

  7. Au nanoparticles films used in biological sensing

    Science.gov (United States)

    Rosales Pérez, M.; Delgado Macuil, R.; Rojas López, M.; Gayou, V. L.; Sánchez Ramírez, J. F.

    2009-05-01

    Lactobacillus para paracasei are used commonly as functional food and probiotic substances. In this work Au nanoparticles self-assembled films were used for Lactobacillus para paracasei determination at five different concentrations. Functionalized substrates were immersed in a colloidal solution for one and a half hour at room temperature and dried at room temperature during four hours. After that, drops of Lactobacillus para paracasei in aqueous solution were put into the Au nanoparticles film and let dry at room temperature for another two hours. Infrared spectroscopy in attenuated total reflectance sampling mode was used to observe generation peaks due to substrate silanization, enhancement of Si-O band intensity due to the Au colloids added to silanized substrate and also to observe the enhancement of Lactobacillus para paracasei infrared intensity of the characteristic frequencies at 1650, 1534 and 1450 cm-1 due to surface enhancement infrared absorption.

  8. Pracovní spokojenost au-pair

    OpenAIRE

    Tomíšková, Tereza

    2013-01-01

    The topic of the following diploma thesis is the explanation of the concept of job satisfaction while holding an au-pair position. The aim of this thesis is to analyze the job satisfaction young women (or men), who go abroad to work as au-pair, can feel. The first part of the analysis consists in a theoretical assessment of the mentioned topic, that is to say provide the reader with basic terminology and information about this area of domestic work; we will also sketch out the main factors in...

  9. Desulfurization of thiophene on Au/TiC(001): Au-C interactions and charge polarization.

    Science.gov (United States)

    Rodriguez, José A; Liu, Ping; Takahashi, Yoshiro; Nakamura, Kenichi; Viñes, Francesc; Illas, Francesc

    2009-06-24

    Photoemission and first-principles DF calculations were used to study the interaction of thiophene with TiC(001) and Au/TiC(001) surfaces. The adsorption strength of thiophene on TiC(001) is weak, and the molecule desorbs at temperatures below 200 K. The molecule binds to Ti centers of TiC(001) through its sulfur atom with negligible structural perturbations. In spite of the very poor desulfurization performance of TiC(001) or Au(111), a Au/TiC(001) system displays a hydrodesulfurization activity higher than that of conventional Ni/MoS(x) catalysts. The AuTiC(001) interactions induce a polarization of electron density around Au which substantially increases the chemical reactivity of this metal. Au nanoparticles drastically increase the hydrodesulfurization activity of TiC(001) by enhancing the bonding energy of thiophene and by helping in the dissociation of H(2) to produce the hydrogen necessary for the hydrogenolysis of C-S bonds and the removal of sulfur. H(2) spontaneously dissociates on small two-dimensional clusters of gold in contact with TiC(001). On these systems, the adsorption energy of thiophene is 0.45-0.65 eV larger than that on TiC(001) or Au(111). Thiophene binds in a eta(5) configuration with a large elongation (approximately 0.2 A) of the C-S bonds. PMID:19530731

  10. Ω production in p+p, Au+Au and U+U collisions at STAR

    International Nuclear Information System (INIS)

    We report STAR's high precision measurements on Ω production at mid-rapidity from √(s)=200 GeVp+p, central √(sNN)=200 GeVAu+Au, and central √(sNN)=193 GeVU+U collisions. With the significantly reduced uncertainty in p+p reference, we observe that the Ω enhancement factors at RHIC are in between SPS and LHC, while enhancement factors are systematically larger in central U+U collisions than in central Au+Au collisions. The ΩRAA is much larger than protons and pions for pT up to 4 GeV/c in central Au+Au collisions. The ratio of ΩRAA in central U+U to that in central Au+Au collisions is above unity for pT up to 6 GeV/c, which indicates coalescence/recombination to be the dominant production mechanism for Ω in these collisions for the measured pT range

  11. Plasmonic Fano resonance and dip of Au-SiO2-Au nanomatryoshka.

    Science.gov (United States)

    Liaw, Jiunn-Woei; Chen, Huang-Chih; Kuo, Mao-Kuen

    2013-01-01

    This study theoretically investigates Fano resonances and dips of an Au-SiO2-Au nanomatryoshka that is excited by a nearby electric dipole. An analytical solution of dyadic Green's functions is used to analyze the radiative and nonradiative power spectra of a radial dipole in the proximity of a nanomatryoshka. From these spectra, the plasmon modes and Fano resonances that accompany the Fano dips are identified. In addition, the scattering and absorption spectra of a nanomatryoshka that is illuminated by a plane wave are investigated to confirm these modes and Fano dips. Our results reveal that a Fano dip splits each of the dipole and quadrupole modes into bonding and anti-bonding modes. The Fano dip and resonance result from the destructive interference of the plasmon modes of the Au shell and the Au core. The Fano factors that are obtained from the nonradiative power spectra of the Au shell and the Au core of a nanomatryoshka are in accordance with those obtained from the absorption cross section spectra. Moreover, these Fano factors increase as the plasmonic coupling of the Au shell with the core increases for both dipole and quadrupole modes. PMID:24206789

  12. Contribution to the study of the biological properties of compounds labeled with radio-chromium {sup 51}Cr; Contribution a l'etude des proprietes biologiques des composes marques au radiochrome {sup 51}Cr

    Energy Technology Data Exchange (ETDEWEB)

    Ingrand, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-15

    Among the radioisotopes commonly used in biology and medicine which are controlled Individually in the Radioelement Departement of the Saclay Nuclear Research Centre before being sent to the users, the author has chosen chromium 51 incorporated in inorganic salts or in organic substrates for a study of the biological properties of the compounds. In the first part, he has compared the pathways followed by the radioactive sodium chromate and chromic chloride mixed with blood or given to the whole animal, the object being to determine whether a reduction of hexavalent chromium occurs, both in vitro and in vivo. In the second part, the author has tried to show the validity of using, various substrates labeled with chromium 51, red cells, haemoglobin, plasma proteins and cytochrome c. The results obtained have contributed to underline the interest of using such compounds for biological applications. (author) [French] Parmi les radioisotopes d'utilisation courants en biologie et en medecine qui sont l'objet d'un controle particulier dans le Departement des Radioelements du Centre d'Etudes Nucleaires de Saclay avant leur diffusion aux utilisateurs, l'auteur a choisi le chrome 51 incorpore a des sels mineraux ou a des substrats organiques, afin d'en etudier les proprietes biologiques. Dans la premiere partie, il a compare le sort du chromate de sodium et du chlorure chromique radioactifs melanges a du sang ou administres a l'animal entier en s'efforcant de mettre en evidence une reduction du chrome hexavalent aussi bien in vitro qu'in vivo. Dans la deuxieme partie, il a cherche a etablir la validite de l'emploi de differents substrats marques au chrome 51, l'hematie, l'hemoglobine, les proteines plasmatiques et le cytochrome c. Les resultats obtenus ont permis de souligner le reel interet des applications biologiques des composes marques par le radioisotope. (auteur)

  13. Azimuthal di-hadron correlations in d+Au and Au+Au collisions at $\\sqrt{s_{NN}}=200$ GeV from STAR

    CERN Document Server

    Aggarwal, M M; Alakhverdyants, A V; Alekseev, I; Alford, J; Anderson, B D; Anson, Daniel; Arkhipkin, D; Averichev, G S; Balewski, J; Barnby, L S; Baumgart, S; Beavis, D R; Bellwied, R; Betancourt, M J; Betts, R R; Bhasin, A; Bhati, A K; Bichsel, H; Bielcik, J; Bielcikova, J; Biritz, B; Bland, L C; Bonner, B E; Bouchet, J; Braidot, E; Brandin, A V; Bridgeman, A; Bruna, E; Bueltmann, S; Bunzarov, I; Burton, T P; Cai, X Z; Caines, H; Calderon, M; Catu, O; Cebra, D; Cendejas, R; Cervantes, M C; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, J Y; Cheng, J; Cherney, M; Chikanian, A; Choi, K E; Christie, W; Chung, P; Clarke, R F; Codrington, M J M; Corliss, R; Cramer, J G; Crawford, H J; Das, D; Dash, S; Leyva, A Davila; De Silva, L C; Debbe, R R; Dedovich, T G; Derevschikov, A A; de Souza, R Derradi; Didenko, L; Djawotho, P; Dogra, S M; Dong, X; Drachenberg, J L; Draper, J E; Dunlop, J C; Mazumdar, M R Dutta; Efimov, L G; Elhalhuli, E; Elnimr, M; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Eun, L; Evdokimov, O; Fachini, P; Fatemi, R; Fedorisin, J; Fersch, R G; Filip, P; Finch, E; Fine, V; Fisyak, Y; Gagliardi, C A; Gangadharan, D R; Ganti, M S; Garcia-Solis, E J; Geromitsos, A; Geurts, F; Ghazikhanian, V; Ghosh, P; Gorbunov, Y N; Gordon, A; Grebenyuk, O; Grosnick, D; Guertin, S M; Gupta, A; Gupta, N; Guryn, W; Haag, B; Hamed, A; Han, L-X; Harris, J W; Hays-Wehle, J P; Heinz, M; Heppelmann, S; Hirsch, A; Hjort, E; Hoffman, A M; Hoffmann, G W; Hofman, D J; Huang, B; Huang, H Z; Humanic, T J; Huo, L; Igo, G; Jacobs, P; Jacobs, W W; Jena, C; Jin, F; Jones, C L; Jones, P G; Joseph, J; Judd, E G; Kabana, S; Kajimoto, K; Kang, K; Kapitan, J; Kauder, K; Keane, D; Kechechyan, A; Kettler, D; Kikola, D P; Kiryluk, J; Kisiel, A; Klein, S R; Knospe, A G; Kocoloski, A; Koetke, D D; Kollegger, T; Konzer, J; Koralt, I; Koroleva, L; Korsch, W; Kotchenda, L; Kouchpil, V; Kravtsov, P; Krueger, K; Krus, M; Kumar, L; Kurnadi, P; Lamont, M A C; Landgraf, J M; LaPointe, S; Lauret, J; Lebedev, A; Lednicky, R; Lee, C-H; Lee, J H; Leight, W; LeVine, M J; Li, C; Li, L; Li, N; Li, W; Li, X; Li, X; Li, Y; Li, Z M; Lin, G; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, J; Ljubicic, T; Llope, W J; Longacre, R S; Love, W A; Lu, Y; Lukashov, E V; Luo, X; Ma, G L; Ma, Y G; Mahapatra, D P; Majka, R; Mall, O I; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Masui, H; Matis, H S; Matulenko, Yu A; McDonald, D; McShane, T S; Meschanin, A; Milner, R; Minaev, N G; Mioduszewski, S; Mischke, A; Mitrovski, M K; Mohanty, B; Mondal, M M; Morozov, B; Morozov, D A; Munhoz, M G; Nandi, B K; Nattrass, C; Nayak, T K; Nelson, J M; Netrakanti, P K; Ng, M J; Nogach, L V; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldag, E W; Olson, D; Pachr, M; Page, B S; Pal, S K; Pandit, Y; Panebratsev, Y; Pawlak, T; Peitzmann, T; Perevoztchikov, V; Perkins, C; Peryt, W; Phatak, S C; Pile, P; Planinic, M; Ploskon, M A; Pluta, J; Plyku, D; Poljak, N; Poskanzer, A M; Potukuchi, B V K S; Powell, C B; Prindle, D; Pruneau, C; Pruthi, N K; Pujahari, P R; Putschke, J; Qiu, H; Raniwala, R; Raniwala, S; Ray, R L; Redwine, R; Reed, R; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Sahoo, R; Sakai, S; Sakrejda, I; Sakuma, T; Salur, S; Sandweiss, J; Sangaline, E; Schambach, J; Scharenberg, R P; Schmitz, N; Schuster, T R; Seele, J; Seger, J; Selyuzhenkov, I; Seyboth, P; Shahaliev, E; Shao, M; Sharma, M; Shi, S S; Sichtermann, E P; Simon, F; Singaraju, R N; Skoby, M J; Smirnov, N; Sorensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stanislaus, T D S; Staszak, D; Stevens, J R; Stock, R; Strikhanov, M; Stringfellow, B; Suaide, A A P; Suarez, M C; Subba, N L; Sumbera, M; Sun, X M; Sun, Y; Sun, Z; Surrow, B; Svirida, D N; Symons, T J M; de Toledo, A Szanto; Takahashi, J; Tang, A H; Tang, Z; Tarini, L H; Tarnowsky, T; Thein, D; Thomas, J H; Tian, J; Timmins, A R; Timoshenko, S; Tlusty, D; Tokarev, M; Trainor, T A; Tram, V N; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; van Leeuwen, M; van Nieuwenhuizen, G; Vanfossen, J A; Jr.,; Varma, R; Vasconcelos, G M S; Vasiliev, A N; Videbaek, F; Viyogi, Y P; Vokal, S; Voloshin, S A; Wada, M; Walker, M; Wang, F; Wang, G; Wang, H; Wang, J S; Wang, Q; Wang, X L; Wang, Y; Webb, G; Webb, J C; Westfall, G D; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wu, Y F; Xie, W; Xu, H; Xu, N; Xu, Q H; Xu, W; Xu, Y; Xu, Z; Xue, L; Yang, Y; Yepes, P; Yip, K; Yoo, I-K; Yue, Q; Zawisza, M; Zbroszczyk, H; Zhan, W; Zhang, J B; Zhang, S; Zhang, W M; Zhang, X P; Zhang, Y; Zhang, Z P; Zhao, J; Zhong, C; Zhou, J; Zhou, W; Zhu, X; Zhu, Y H; Zoulkarneev, R; Zoulkarneeva, Y

    2010-01-01

    Yields, correlation shapes, and mean transverse momenta \\pt{} of charged particles associated with intermediate to high-\\pt{} trigger particles ($2.5 < \\pt < 10$ \\GeVc) in d+Au and Au+Au collisions at $\\snn=200$ GeV are presented. For associated particles at higher $\\pt \\gtrsim 2.5$ \\GeVc, narrow correlation peaks are seen in d+Au and Au+Au, indicating that the main production mechanism is jet fragmentation. At lower associated particle $\\pt < 2$ \\GeVc, a large enhancement of the near- ($\\dphi \\sim 0$) and away-side ($\\dphi \\sim \\pi$) associated yields is found, together with a strong broadening of the away-side azimuthal distributions in Au+Au collisions compared to d+Au measurements, suggesting that other particle production mechanisms play a role. This is further supported by the observed significant softening of the away-side associated particle yield distribution at $\\dphi \\sim \\pi$ in central Au+Au collisions.

  14. Production of omega mesons in p+p, d+Au, Cu+Cu, and Au+Au collisions at sqrt(s_NN)=200 GeV

    CERN Document Server

    Adare, A; Aidala, C; Ajitanand, N N; Akiba, Y; Al-Bataineh, H; Al-Jamel, A; Alexander, J; Angerami, A; Aoki, K; Apadula, N; Aphecetche, L; Aramaki, Y; Armendariz, R; Aronson, S H; Asai, J; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Baksay, G; Baksay, L; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Basye, A T; Bathe, S; Batsouli, S; Baublis, V; Bauer, F; Baumann, C; Bazilevsky, A; Belikov, S; Belmont, R; Bennett, R; Berdnikov, A; Berdnikov, Y; Bhom, J H; Bickley, A A; Bjorndal, M T; Blau, D S; Boissevain, J G; Bok, J S; Borel, H; Boyle, K; Brooks, M L; Brown, D S; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camacho, C M; Campbell, S; Caringi, A; Chai, J -S; 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; Cobigo, Y; 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; David, G; Dayananda, M K; Deaton, M B; Dehmelt, K; Delagrange, H; Denisov, A; d'Enterria, D; Deshpande, A; Desmond, E J; Dharmawardane, K V; Dietzsch, O; Dion, A; Donadelli, M; Drachenberg, J L; 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; Espagnon, B; Esumi, S; Eyser, K O; Fadem, B; Fields, D E; Finger, M; Finger, M; Fleuret, F; Fokin, S L; Forestier, B; Fraenkel, Z; 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; de Cassagnac, R Granier; Grau, N; Greene, S V; Grim, G; Perdekamp, M Grosse; Gunji, T; Gustafsson, H -Å; Hachiya, T; Henni, A Hadj; Haegemann, C; Haggerty, J S; Hagiwara, M N; Hahn, K I; Hamagaki, H; Hamblen, J; Han, R; Hanks, J; Harada, H; Hartouni, E P; Haruna, K; Harvey, M; Haslum, E; Hasuko, K; Hayano, R; He, X; Heffner, M; Hemmick, T K; Hester, T; Heuser, J M; Hiejima, H; Hill, J C; Hobbs, R; Hohlmann, M; Holmes, M; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hornback, D; Huang, S; Hur, M G; Ichihara, T; Ichimiya, R; Ide, J; Iinuma, H; Ikeda, Y; Imai, K; Inaba, M; Inoue, Y; Isenhower, D; Isenhower, L; Ishihara, M; Isobe, T; Issah, M; Isupov, A; Ivanischev, D; Iwanaga, Y; Jacak, B V; Jia, J; Jiang, X; Jin, J; Jinnouchi, O; Johnson, B M; Jones, T; Joo, K S; Jouan, D; Jumper, D S; Kajihara, F; Kametani, S; Kamihara, N; Kamin, J; Kaneta, M; Kang, J H; Kanou, H; Kapustinsky, J; Karatsu, K; Kasai, M; Kawagishi, T; Kawall, D; Kawashima, M; Kazantsev, A V; Kelly, S; Kempel, T; Khanzadeev, A; Kijima, K M; Kikuchi, J; Kim, A; Kim, B I; Kim, D H; Kim, D J; Kim, E; Kim, E J; Kim, S H; Kim, Y -J; Kim, Y -S; Kim, Y J; Kinney, E; Kiriluk, K; Kiss, Á; Kistenev, E; Kiyomichi, A; Klay, J; Klein-Boesing, C; Kochenda, L; Kochetkov, V; Komkov, B; Konno, M; Koster, J; Kotchetkov, D; Kozlov, A; Král, A; Kravitz, A; Kroon, P J; 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; Bornec, Y Le; Leckey, S; Lee, D M; Lee, J; Lee, K; Lee, K B; Lee, K S; Lee, M K; Lee, T; Leitch, M J; Leite, M A L; Leitner, E; Lenzi, B; Li, X; Li, X H; Lichtenwalner, P; Liebing, P; Lim, H; Levy, L A Linden; Liška, T; Litvinenko, A; Liu, H; Liu, M X; Love, B; Luechtenborg, R; Lynch, D; Maguire, C F; Makdisi, Y I; Malakhov, A; Malik, M D; Manko, V I; Mannel, E; Mao, Y; Mašek, L; Masui, H; Matathias, F; McCain, M C; McCumber, M; McGaughey, P L; Means, N; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Mikeš, P; Miki, K; Miller, T E; Milov, A; Mioduszewski, S; Mishra, G C; Mishra, M; Mitchell, J T; Mitrovski, M; Mohanty, A K; Moon, H J; Morino, Y; Morreale, A; Morrison, D P; Moss, J M; Moukhanova, T V; Mukhopadhyay, D; Murakami, T; Murata, J; Nagamiya, S; Nagata, Y; Nagle, J L; Naglis, M; Nagy, M I; Nakagawa, I; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nam, S; Newby, J; Nguyen, M; Nihashi, M; Norman, B E; Nouicer, R; Nyanin, A S; Nystrand, J; Oakley, C; O'Brien, E; Oda, S X; Ogilvie, C A; Ohnishi, H; Ojha, I D; Oka, M; Okada, K; Omiwade, O O; Onuki, Y; Oskarsson, A; Otterlund, I; Ouchida, M; Ozawa, K; Pak, R; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, I H; Park, J; Park, S K; Park, W J; Pate, S F; Pei, H; Peng, J -C; Pereira, H; Peresedov, V; Peressounko, D Yu; Petti, R; Pinkenburg, C; 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; Riabov, V; Riabov, Y; Richardson, E; Roach, D; Roche, G; Rolnick, S D; Romana, A; Rosati, M; Rosen, C A; Rosendahl, S S E; Rosnet, P; Rukoyatkin, P; Ružička, P; Rykov, V L; Ryu, S S; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakai, S; Sakashita, K; Sakata, H; Samsonov, V; Sano, S; Sato, H D; Sato, S; Sato, T; Sawada, S; Sedgwick, K; Seele, J; Seidl, R; Semenov, A Yu; Semenov, V; Seto, R; Sharma, D; Shea, T K; Shein, I; Shevel, A; Shibata, T -A; Shigaki, K; Shimomura, M; Shohjoh, T; 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; Smith, W C; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Sparks, N A; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Suire, C; Sukhanov, A; Sullivan, J P; Sziklai, J; Tabaru, T; Takagi, S; Takagui, E M; Taketani, A; Tanabe, R; Tanaka, K H; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tarján, P; Themann, H; Thomas, D; Thomas, T L; Togawa, M; Toia, A; Tojo, J; Tomášek, L; Torii, H; Towell, R S; Tram, V-N; Tserruya, I; Tsuchimoto, Y; Tuli, S K; Tydesjö, H; Tyurin, N; Vale, C; Valle, H; van Hecke, H W; 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; Wei, F; Wei, R; Wessels, J; White, S N; Willis, N; Winter, D; Wood, J P; Woody, C L; Wright, R M; Wysocki, M; Xie, W; Yamaguchi, Y L; Yamaura, K; Yang, R; Yanovich, A; Yasin, Z; Ying, J; Yokkaichi, S; You, Z; Young, G R; Younus, I; Yushmanov, I E; Zajc, W A; Zaudtke, O; Zhang, C; Zhou, S; Zimányi, J; Zolin, L

    2011-01-01

    The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) has measured omega meson production via leptonic and hadronic decay channels in p+p, d+Au, Cu+Cu, and Au+Au collisions at sqrt(s_NN) = 200 GeV. The invariant transverse momentum spectra measured in different decay modes give consistent results. Measurements in the hadronic decay channel in Cu+Cu and Au+Au collisions show that omega production has a suppression pattern at high transverse momentum, similar to that of pi^0 and eta in central collisions, but no suppression is observed in peripheral collisions. The nuclear modification factors, R_AA, are consistent in Cu+Cu and Au+Au collisions at similar numbers of participant nucleons.

  15. Crystal structure of Au9In4(h) and Au7In3

    International Nuclear Information System (INIS)

    The phase Au9In4(h) crystallizes in the Cu9Al4-type structure and Au7In3 has a hexagonal crystal structure with 60 atoms in the elementary cell. The structure is related to the γ-brass structure but with a different distribution of vacancies and another system of displacements. A spatial correlation of the core electrons with a very simple commensurability may be traced in the structure, together with a valence electron correlation which is geometrically related to the core electron correlation by a factor of 2. This energetically favourable binding relationship provides an argument in favour of the stability of Au7In3. (Auth.)

  16. Revisiting the S-Au(111) interaction: Static or Dynamic?

    Energy Technology Data Exchange (ETDEWEB)

    Biener, M M; Biener, J; Friend, C M

    2004-08-17

    The chemical inertness typically observed for Au does not imply a general inability to form stable bonds with non-metals but is rather a consequence of high reaction barriers. The Au-S interaction is probably the most intensively studied interaction of Au surfaces with non-metals as, for example, it plays an important role in Au ore formation, and controls the structure and dynamics of thiol-based self-assembled-monolayers (SAMs). In recent years a quite complex picture of the interaction of sulfur with Au(111) surfaces emerged, and a variety of S-induced surface structures was reported under different conditions. The majority of these structures were interpreted in terms of a static Au surface, where the positions of the Au atoms remain essentially unperturbed. Here we demonstrate that the Au(111) surface exhibits a very dynamic character upon interaction with adsorbed sulfur: low sulfur coverages modify the surface stress of the Au surface leading to lateral expansion of the surface layer; large-scale surface restructuring and incorporation of Au atoms into a growing two-dimensional AuS phase were observed with increasing sulfur coverage. These results provide new insight into the Au-S surface chemistry, and reveal the dynamic character of the Au(111) surface.

  17. Au-nano-delci in njihova uporaba

    OpenAIRE

    Rudolf, Rebeka; Zorko, Lidija; Anžel, Ivan

    2012-01-01

    Razvoj tehnik za sintezo Au-nano delcev z določeno velikostjo, obliko in sestavo je izziv in pomembno področje raziskav v nanotehnologiji. Zlati nanodelci so namreč atraktivni zaradi potencialne uporabe v elektrokemiji in medicini, kot tudi za proizvodnjo različnih nano-naprav.

  18. 2010 Port-au-Prince, Haiti Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — According to official estimates, 222,570 people killed, 300,000 injured, 1.3 million displaced, 97,294 houses destroyed and 188,383 damaged in the Port-au-Prince...

  19. Didaktik des außerschulischen Lernens

    CERN Document Server

    Sauerborn, Petra

    2012-01-01

    Kernprobleme schulischer Bildung sind die zunehmenden Verluste an Realitäts- und Praxisbezug sowie die einseitige Betonung der fachwissenschaftlichen Kenntnisse. In jüngster Zeit werden insbesondere moderne didaktisch-methodische Konzepte näher diskutiert und praktiziert. So finden sich etwa die Stichwörter Handlungsorientierter Unterricht und Offener Unterricht in der fachdidaktischen Diskussion wieder. Eine wesentlich aktuellere Form stellt das außerschulische Lernen dar. Ein modernes pädagogisches Verständnis sieht den Unterricht heute nicht mehr als ausschließliche Tätigkeit des Lehrers an, sondern als Aktivität der Lernenden. Außerschulisches Lernen beschreibt die originale Begegnung im Unterricht außerhalb des Klassenzimmers. An außerschulischen Lernorten findet eine unmittelbare AuseinanderSetzung des Lernenden mit seiner räumlichen Umgebung statt. Charakteristisch sind hierbei vor allem die aktive(Mit-)Gestaltung sowie die eigenständige Wahrnehmung mehrperspektivischer Bildungsinhalte d...

  20. Interface stress in Au/Ni multilayers

    DEFF Research Database (Denmark)

    Schweitz, K.O.; Böttiger, J.; Chevallier, J.; Feidenhans'l, Robert Krarup; Nielsen, Martin Meedom; Rasmussen, Frank Berg

    2000-01-01

    The effect of intermixing on the apparent interface stress is studied in < 111 >-textured dc-magnetron sputtered Au/Ni multilayers by use of two methods commonly used for determining interface stress. The method using profilometry and in-plane x-ray diffraction does not take intermixing into...

  1. Camus ou l’artiste au travail

    Directory of Open Access Journals (Sweden)

    Inmaculada Cuquerella Madoz

    2015-12-01

    Full Text Available « Camus ou l’artiste au travail » voudrait rappeler quelques aspects du riche parcours vital, littéraire et intellectuel de l’écrivain et penseur français Albert Camus. C’est à partir de la nouvelle « Jonas ou l’artiste au travail », rédigée vers 1953, que ce portrait sera dressé. Camus y propose une satire mordante du milieu artistique et intellectuel parisien où il étouffe et dépérit depuis la controverse, provoquée par la parution de son essai L’Homme révolté, qui l’oppose au cercle sartrien et à la gauche communiste. Ce conte philosophique, assez énigmatique et bien moins connu que les romans majeurs que sont L’Étranger, La Peste ou La Chute, permet cependant de creuser dans l’univers tragique de l’auteur qui, à l’image de ce qui arrive au peintre Jonas (et que l’on retrouve chez l’étranger Meursault, le docteur Rieux et le juge-pénitent Clamence se sent tiraillé entre l’existence solitaire et l’existence solidaire.

  2. Forward-backward multiplicity correlation in Au+Au collisions at RHIC with transport model PACIAE

    CERN Document Server

    Yan, Yu-Liang; Dong, Bao-Guo; Li, Xiao-Mei; Ma, Hai-Liang; Sa, Ben-Hao

    2009-01-01

    We have studied the charged particle forward-backward multiplicity correlation strength in 0-10% most central Au+Au collisions at \\sqrt{s_{NN}}=200 GeV by a parton and hadron cascade model, PACIAE based on PYTHIA. The real (total), statistical, and NBD (Negative Binomial Distribution) correlation strengths are calculated, respectively, with the real events, mixed events, and NBD fitting the charged particle multiplicity distribution. The corresponding STAR data are well reproduced by the real one. If the discrepancy between real and statistical correlation strengths is identified as dynamical correlation strength, the dynamical correlation strength is then just counted few percent of the total correlation strength. In addition, we also calculated the 0-5 and 5% most central Au+Au collisions and turned out that the correlation strength increases monotonously with increasing size of the centrality bin.

  3. Dispersion and STM Characterization of Au-CdSe Nanohybrids on Au(111)

    Institute of Scientific and Technical Information of China (English)

    Bo Gao; Yan-min Kuang; Yuan Liao; Zhen-chao Dong

    2012-01-01

    We report the dispersion and scanning tunneling microscopy (STM) characterization of isolated Au-CdSe nanohybrids on atomically flat Au(111) through surface modifications.The top terminal groups of spacer molecules self-assembled on the surface are found critical for locking the nanohybrids into a well-separated state.The STM results indicate that both thiol and carboxylic terminals are effective in this aspect by making strong interaction with the Au portions of the nanohybrids.An argon ion sputtering technique is also proposed to clean up organic contaminants on the surface for improved STM imaging of individual Au-CdSe nanohybrids.These observations help to enrich technical approaches to dispersing individual nanostructures on the surface and provide opportunities to explore their local electroluminescent and energy transfer properties at the nanoscale.

  4. Co L-edge EXAFS analysis of Au/Co/Au/W(110) magnetic thin films

    International Nuclear Information System (INIS)

    Ultrathin Au/Co/Au is known as a prototypical system which shows perpendicular magnetic anisotropy. Our recent XMCD study of in-situ prepared Au/Co/Au/W(110) showed that, contrary to the widely accepted picture, there is no increase of the Co perpendicular orbital moment that accompanies the in-plane to out-of-plane spin reorientation transition (SRT). We performed an in-situ Co L-edge Extended X-ray Absorption Fine Structure (EXAFS) study of the local structure on the same samples whose magnetic properties were characterized using XMCD and X-ray resonant reflectivity. We applied the Bayes-Turchin approach developed by Krappe and Rossner in analyzing the EXAFS spectra. From this analysis, we obtain quantitative information about the structural strain and disorder of the Co layers. We discuss the role of the local structural modifications among the mechanisms responsible for the occurence of the SRT

  5. Simulation of energy scan of pion interferometry in central Au+Au collisions at relativistic energies

    International Nuclear Information System (INIS)

    We present a systematic analysis of two-pion interferometry for the central Au+Au collisions at √sNN = 3, 5, 7, 11, 17, 27, 39, 62, 130 and 200 GeV/c with the help of a multiphase transport (AMPT) model. Emission source-size radius parameters Rlong, Rout, Rside and the chaotic parameter λ are extracted and compared with the experimental data. Transverse momentum and azimuthal angle dependencies of the HBT radii are also discussed for central Au+Au collisions at 200 GeV/c. The results show that the HBT radii in central collisions do not change much above 7 GeV/c. For central collisions at 200 GeV/c, the radii decrease with the increasing of transverse momentum pT but are not sensitive to the azimuthal angle. These results provide a theoretical reference for the energy scan program of the RHIC-STAR experiment. (authors)

  6. Stability of gold cages (Au16 and Au17) at finite temperature

    Indian Academy of Sciences (India)

    Prachi Chandrachud; Kavita Joshi; Sailaja Krishnamurty; D G Kanhere

    2009-05-01

    We have employed ab initio molecular dynamics to investigate the stability of the smallest gold cages, namely Au16 and Au17, at finite temperatures. First, we obtain the ground state structure along with at least 50 distinct isomers for both the clusters. This is followed by the finite temperature simulations of these clusters. Each cluster is maintained at 12 different temperatures for a time period of at least 150 ps. Thus, the total simulation time is of the order of 2.4 ns for each cluster. We observe that the cages are stable at least up to 850 K. Although both clusters melt around the same temperature, i.e. around 900 K, Au17 shows a peak in the heat capacity curve in contrast to the broad peak seen for Au16.

  7. Three-particle correlations from parton cascades in Au+Au collisions

    International Nuclear Information System (INIS)

    We present a study of three-particle correlations among a trigger particle and two associated particles in Au+Au collisions at sNN=200 GeV using a multi-phase transport model (AMPT) with both partonic and hadronic interactions. We found that three-particle correlation densities in different angular directions with respect to the triggered particle ('center', 'cone', 'deflected', 'near' and 'near-away') increase with the number of participants. The ratio of 'deflected' to 'cone' density approaches to 1.0 with the increasing of number of participants, which indicates that partonic Mach-like shock waves can be produced by strong parton cascades in central Au+Au collisions

  8. Modelling of global crop production and resulting N2O emissions

    OpenAIRE

    Stehfest, Elke

    2005-01-01

    Landwirtschaft spielt eine zentrale Rolle im Erdsystem. Sie trägt durch die Emission von CO2, CH4 und N2O zum Treibhauseffekt bei, kann Bodendegradation und Eutrophierung verursachen, regionale Wasserkreisläufe verändern und wird außerdem stark vom Klimawandel betroffen sein. Da all diese Prozesse durch die zugrunde liegenden Nährstoff- und Wasserflüsse eng miteinander verknüpft sind, sollten sie in einem konsistenten Modellansatz betrachtet werden. Dennoch haben Datenmangel und ungenügendes ...

  9. Some thoughts on di-jet correlation in Au + Au collisions from PHENIX

    CERN Document Server

    Jia, J

    2006-01-01

    PHENIX has measured the two particle azimuth correlation in Au + Au at $\\sqrt{s}$ = 200 GeV. Jet shape and yield at the away side are found to be strongly modified at intermediate and low $p_T$, and the modifications vary dramatically with $p_T$ and centrality. At high $p_T$, away side jet peak reappears but the yield is suppressed. We discuss the possible physics pictures leading to these complicated modifications.

  10. Energy dependence of collective flow of neutrons and charged particles in 197Au+197Au collisions

    International Nuclear Information System (INIS)

    Our contribution focusses on one particular aspect of collective flow of nuclear matter: the so-called ''squeeze-out'', i.e. the preferential emission of mid-rapidity particles perpendicular to the reaction plane. The data were taken for the system 197Au + 197Au at 400, 600 and 800 MeV/u. We cover two topics, the comparison of neutrons and protons, and the bombarding energy dependence of the neutrons' squeeze-out. (orig.)

  11. Charged-particle pseudorapidity distributions in Au+Au collisions at RHIC

    Institute of Scientific and Technical Information of China (English)

    WANG Zeng-Wei; JIANG Zhi-Jin

    2009-01-01

    Using the Glauber model, we present the formulas for calculating the numbers of participants,spectators and binary nucleon-nucleon collisions. Based on this work, we get the pseudorapidity distributions of charged particles as the function of the impact parameter in nucleus-nucleus collisions. The theoretical results agree well with the experimental observations made by the BRAHMS Collaboration in Au+Au collisions at √SNN=200 GeV in different centrality bins over the whole pseudorapidity range.

  12. Hadron yields and spectra in Au+Au collisions at the AGS

    OpenAIRE

    Lacasse, Roger; Collaboration, the E877

    1996-01-01

    Inclusive double differential multiplicities and rapidity density distributions of hadrons are presented for 10.8 A GeV/c Au+Au collisions as measured at the AGS by the E877 collaboration. The results indicate that large amounts of stopping and collective transverse flow effects are present. The data are also compared to the results from the lighter Si+Al system.

  13. Directed Flow of Charged Kaons in Au+Au Collisions from the BES Program at RHIC

    Science.gov (United States)

    Pandit, Yadav; STAR Collaboration

    2015-08-01

    We report the measurement of the directed flow (v1) for charged kaons in Au+Au collisions at =7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV as a function of rapidity and compare these results for pions, protons and antiprotons. These new kaon results may help to constrain the medium properties and collision dynamics including the in-medium kaon potential and baryon number transport in these collisions.

  14. Antiproton production in Au + Au collisions at 11.7 A·GeV/c

    International Nuclear Information System (INIS)

    We investigated the dependence of antiproton yields on the number of wounded projectile nucleons (Nproj). The dN/dy/Nproj of antiprotons with the beam energy correction is almost constant from p+A to Si+A collisions, while it decreases in Au+Au collisions to 30-60% of the constant. Next, we have compared dependence of ratios of dN/dy, p-bar/π-, p/π-, K-/π-, K+/π-, and π+/π- at 1.2proj in Au+Au collisions. Only the ratio of p-bar/π- decreases rapidly, while the ratios of p/π-, K+/π-, and K-/π- increase, and π+/π- stays constant. These observations suggest that in the AGS energy regime, the absorption effect of antiprotons in Au+Au collisions is much stronger than in p+A and Si+A collisions. We have compared the antiproton data with the RQMD model. In RQMD, antiprotons are produced initially from multi-step excitation processes and some of them are absorbed by nucleons with free NN-bar annihilation cross sections. RQMD reproduces overall tendencies of antiproton yields from p+A to Au+Au collisions within 50%. Finally, we explored the relation between baryon densities and antiproton yields in A+A collisions. We used a model in a static participant volume with the RQMD initial production and the absorption length with the free NN-bar annihilation cross section. In the model, only the antiprotons produced around the surface of the participant volume can survive. The model reproduces the scaling of experimental antiproton yields with the 2/3 power of the number of participants. By comparing the model with the experimental data, it is found that the ratio of the mean baryon density to the surface baryon density is 3-4 independent of collision systems. (J.P.N.). 109 refs

  15. Flow and bose-einstein correlations in Au-Au collisions at RHIC

    Science.gov (United States)

    Phobos Collaboration; Manly, Steven; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Henderson, C.; Hofman, D.; Hollis, R. S.; Hołyinski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A.; 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.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2003-03-01

    Argonne flow and Bose-Einstein correlations have been measured in Au-Au collisions at S=130 and 200 GeV using the PHOBOS detector at RHIC. The systematic dependencies of the flow signal on the transverse momentum, pseudorapidity, and centrality of the collision, as well as the beam energy are shown. In addition, results of a 3-dimensional analysis of two-pion correlations in the 200 GeV data are presented.

  16. Results from experiment E917 for Au + Au collisions at the AGS

    International Nuclear Information System (INIS)

    The effects of baryon stopping and its resulting energy deposition on the dynamics of Au + Au collisions at 6, 8 and 10.8 GeV/nucleon are explored with recent results from the AGS experiment E917. Current analyses of stopping, collective flow signals and HBT parameters are presented. Strangeness and anti-baryon production is examined using the yields of anti-lambdas and anti-protons

  17. Nuclear modification factors of phi mesons in d+Au, Cu+Cu and Au+Au collisions at sqrt(S_NN)=200 GeV

    CERN Document Server

    Adare, A; Aidala, C; Ajitanand, N N; Akiba, Y; Al-Bataineh, H; Alexander, J; Al-Jamel, A; Angerami, A; Aoki, K; Aphecetche, L; Aramaki, Y; Armendariz, R; Aronson, S H; Asai, J; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Baksay, G; Baksay, L; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Basye, A T; Bathe, S; Batsouli, S; Baublis, V; Bauer, F; Baumann, C; Bazilevsky, A; Belikov, S; Belmont, R; Bennett, R; Berdnikov, A; Berdnikov, Y; Bhom, J H; Bickley, A A; Bjorndal, M T; Blau, D S; Boissevain, J G; Bok, J S; Borel, H; Borggren, N; Boyle, K; Brooks, M L; Brown, D S; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Campbell, S; Caringi, A; Cassano, N; Chai, J -S; Chang, B S; Charvet, J -L; Chen, C -H; Chernichenko, S; Chiba, J; Chi, C Y; 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; Cobigo, Y; Cole, B A; Comets, M P; del Valle, Z Conesa; Connors, M; Constantin, P; Csanad, M; Csorgo, T; Dahms, T; Dairaku, S; Danchev, I; Das, K; Datta, A; David, G; Dayananda, M K; Deaton, M B; Dehmelt, K; Delagrange, H; Denisov, A; d'Enterria, D; Deshpande, A; Desmond, E J; Dharmawardane, K V; Dietzsch, O; Dion, A; Donadelli, M; Orazio, L D; Drachenberg, J L; Drapier, O; Drees, A; Drees, K A; Dubey, A K; Durham, J M; Durum, A; Dutta, D; Dzhordzhadze, V; Edwards, S; Efremenko, Y V; Egdemir, J; Ellinghaus, F; Emam, W S; Engelmore, T; Enokizono, A; En'yo, H; Espagnon, B; Esumi, S; Eyser, K O; Fadem, B; Fields, D E; Finger, M; Finger, M; Fleuret, F; Fokin, S L; Forestier, B; Fraenkel, Z; 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; de Cassagnac, R Granier; Grau, N; Greene, S V; Grim, G; Perdekamp, M Grosse; Gunji, T; Gustafsson, H -A; Hachiya, T; Henni, A Hadj; Haegemann, C; Haggerty, J S; Hagiwara, M N; Hahn, K I; Hamagaki, H; Hamblen, J; Hanks, J; Han, R; 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; Hiejima, H; Hill, J C; Hobbs, R; Hohlmann, M; Holmes, M; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hornback, D; Huang, S; Hur, M G; Ichihara, T; Ichimiya, R; Iinuma, H; Ikeda, Y; Imai, K; Inaba, M; Inoue, Y; Isenhower, D; Isenhower, L; Ishihara, M; Isobe, T; Issah, M; Isupov, A; Ivanischev, D; Iwanaga, Y; Jacak, B V; Jia, J; Jiang, X; Jin, J; Jinnouchi, O; Johnson, B M; Jones, T; Joo, K S; Jouan, D; Jumper, D S; Kajihara, F; Kametani, S; Kamihara, N; Kamin, J; Kaneta, M; Kang, J H; Kanou, H; Kapustinsky, J; Karatsu, K; Kasai, M; Kawagishi, T; Kawall, D; Kawashima, M; Kazantsev, A V; Kelly, S; Kempel, T; Khanzadeev, A; Kijima, K M; Kikuchi, J; Kim, A; Kim, B I; Kim, D H; Kim, D J; Kim, E J; Kim, E; Kim, Y -J; Kim, Y -S; Kinney, E; Kiss, A; Kistenev, E; Kiyomichi, A; Klay, J; Klein-Boesing, C; Kochenda, L; Kochetkov, V; Komkov, B; Konno, M; Koster, J; Kotchetkov, D; Kotov, D; Kozlov, A; Kral, A; Kravitz, A; Kroon, P J; 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; Le Bornec, Y; Leckey, S; Lee, D M; Lee, J; Lee, K B; Lee, K S; Lee, M K; Lee, T; Leitch, M J; Leite, M A L; Lenzi, B; Lichtenwalner, P; Liebing, P; Lim, H; Levy, L A Linden; Liska, T; Litvinenko, A; Liu, H; Liu, M X; Li, X; Li, X H; Love, B; Lynch, D; Maguire, C F; Makdisi, Y I; Malakhov, A; Malik, M D; Manko, V I; Mannel, E; Mao, Y; Masek, L; Masui, H; Matathias, F; McCain, M C; McCumber, M; McGaughey, P L; Means, N; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Mikes, P; Miki, K; Miller, T E; Milov, A; Mioduszewski, S; Mishra, G C; Mishra, M; Mitchell, J T; Mitrovski, M; Mohanty, A K; Moon, H J; Morino, Y; Morreale, A; Morrison, D P; Moss, J M; Moukhanova, T V; Mukhopadhyay, D; Murakami, T; Murata, J; Nagamiya, S; Nagata, Y; Nagle, J L; Naglis, M; Nagy, M I; Nakagawa, I; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nam, S; Newby, J; Nguyen, M; Nihashi, M; Norman, B E; Nouicer, R; Nyanin, A S; Nystrand, J; Oakley, C; O'Brien, E; Oda, S X; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Oka, M; Omiwade, O O; Onuki, Y; Oskarsson, A; Otterlund, I; Ouchida, M; Ozawa, K; Pak, R; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, I H; Park, J; Park, S K; Park, W J; Pate, S F; Pei, H; Peng, J -C; Pereira, H; Peresedov, V; Peressounko, D Yu; Petti, R; Pinkenburg, C; 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; Riabov, V; Riabov, Y; Richardson, E; Roach, D; Roche, G; Rolnick, S D; Romana, A; Rosati, M; Rosen, C A; Rosendahl, S S E; Rosnet, P; Rukoyatkin, P; Ruzicka, P; Rykov, V L; Ryu, S S; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakai, S; Sakashita, K; Sakata, H; Samsonov, V; Sano, S; Sato, H D; Sato, S; Sato, T; Sawada, S; Sedgwick, K; 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; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, B K; Singh, C P; Singh, V; Skutnik, S; Slunecka, M; Smith, W C; 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; Sullivan, J P; Sziklai, J; Tabaru, T; Takagi, S; Takagui, E M; Taketani, A; Tanabe, R; Tanaka, K H; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tarjan, P; Themann, H; Thomas, D; Thomas, T L; Togawa, M; Toia, A; Tojo, J; Tomasek, L; Torii, H; Towell, R S; Tram, V-N; Tserruya, I; Tsuchimoto, Y; Tuli, S K; Tydesjo, H; Tyurin, N; Vale, C; Valle, H; van Hecke, H W; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vertesi, R; Vinogradov, A A; Virius, M; Vrba, V; Vznuzdaev, E; Wagner, M; Walker, D; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Wei, F; Wessels, J; White, S N; Willis, N; Winter, D; Woody, C L; Wright, R M; Wysocki, M; Xie, W; Yamaguchi, Y L; Yamaura, K; Yang, R; Yanovich, A; Yasin, Z; Ying, J; Yokkaichi, S; Young, G R; Younus, I; You, Z; Yushmanov, I E; Zajc, W A; Zaudtke, O; Zhang, C; Zhou, S; Zimanyi, J; Zolin, L

    2010-01-01

    The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) has performed systematic measurements of phi meson production in the K+K- decay channel at midrapidity in p+p, d+Au, Cu+Cu and Au+Au collisions at sqrt(S_NN)=200 GeV. Results are presented on the phi invariant yield and the nuclear modification factor R_AA for Au+Au and Cu+Cu, and R_dA for d+Au collisions, studied as a function of transverse momentum (1Au+Au collisions, the R_AA of phi exhibits a suppression relative to expectations from binary scaled p+p results. The amount of suppression is smaller than that of the neutral pion and the eta meson in the intermediate p_T range (2--5 GeV/c); whereas at higher p_T the phi, pi^0, and eta show similar suppression. The baryon (protons and anti-protons) excess observed in central Au+Au collisions at intermediate p_T is not observed for the phi meson despite the similar mass of the proton and the phi. This suggests that the excess is lin...

  18. Suppression of Upsilon Production in d+Au and Au+Au Collisions at sqrt(s_NN) = 200 GeV

    CERN Document Server

    Adamczyk, L; Agakishiev, G; Aggarwal, M M; Ahammed, Z; Alekseev, I; Alford, J; Anson, C D; Aparin, A; Arkhipkin, D; Aschenauer, E C; Averichev, G S; Banerjee, A; Beavis, D R; Bellwied, R; Bhasin, A; Bhati, A K; Bhattarai, P; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Bordyuzhin, I G; Borowski, W; Bouchet, J; Brandin, A V; Brovko, S G; Bültmann, S; Bunzarov, I; Burton, T P; Butterworth, J; Caines, H; Sánchez, M Calderón de la Barca; Cebra, D; Cendejas, R; Cervantes, M C; Chaloupka, P; Chang, Z; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, L; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Chwastowski, J; Codrington, M J M; Contin, G; Cramer, J G; Crawford, H J; Cui, X; Das, S; Leyva, A Davila; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; Derevschikov, A A; de Souza, R Derradi; Dhamija, S; di Ruzza, B; Didenko, L; Dilks, C; Ding, F; Djawotho, P; Dong, X; Drachenberg, J L; Draper, J E; Du, C M; Dunkelberger, L E; Dunlop, J C; Efimov, L G; Engelage, J; Engle, K S; Eppley, G; Eun, L; Evdokimov, O; Fatemi, R; Fazio, S; Fedorisin, J; Filip, P; Finch, E; Fisyak, Y; Flores, C E; Gagliardi, C A; Gangadharan, D R; Garand, D; Geurts, F; Gibson, A; Girard, M; Gliske, S; Greiner, L; Grosnick, D; Guo, Y; Gupta, A; Gupta, S; Guryn, W; Haag, B; Hajkova, O; Hamed, A; Han, L-X; Haque, R; Harris, J W; Heppelmann, S; Hill, K; Hirsch, A; Hoffmann, G W; Hofman, D J; Horvat, S; Huang, B; Huang, H Z; Huang, X; Huck, P; Humanic, T J; Igo, G; Jacobs, W W; Jang, H; Judd, E G; Kabana, S; Kalinkin, D; Kang, K; Kauder, K; Ke, H W; Keane, D; Kechechyan, A; Kesich, A; Khan, Z H; Kikola, D P; Kisel, I; Kisiel, A; Koetke, D D; Kollegger, T; Konzer, J; Koralt, I; Kotchenda, L; Kravtsov, P; Krueger, K; Kulakov, I; Kumar, L; Kycia, R A; Lamont, M A C; Landgraf, J M; Landry, K D; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; LeVine, M J; Li, C; Li, W; Li, X; Li, Y; Li, Z M; Lima, L M; Lisa, M A; Liu, F; Ljubicic, T; Llope, W J; Lomnitz, M; Longacre, R S; Luo, X; Ma, G L; Ma, Y G; Don, D M M D Madagodagettige; Mahapatra, D P; Majka, R; Margetis, S; Markert, C; Masui, H; Matis, H S; McDonald, D; McShane, T S; Minaev, N G; Mioduszewski, S; Mohanty, B; Mondal, M M; Morozov, D A; Munhoz, M G; Mustafa, M K; Nandi, B K; Nasim, Md; Nayak, T K; Nelson, J M; Nigmatkulov, G; Nogach, L V; Noh, S Y; Novak, J; Nurushev, S B; Odyniec, G; Ogawa, A; Oh, K; Ohlson, A; Okorokov, V; Oldag, E W; Oliveira, R A N; Pachr, M; Page, B S; Pal, S K; Pan, Y X; Pandit, Y; Panebratsev, Y; Pawlak, T; Pawlik, B; Pei, H; Perkins, C; Peryt, W; Peterson, A; Pile, P; Planinic, M; Pluta, J; Poljak, N; Porter, J; Poskanzer, A M; Pruthi, N K; Przybycien, M; Pujahari, P R; Putschke, J; Qiu, H; Quintero, A; Ramachandran, S; Raniwala, R; Raniwala, S; Ray, R L; Riley, C K; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Ross, J F; Roy, A; Ruan, L; Rusnak, J; Sahoo, N R; Sahu, P K; Sakrejda, I; Salur, S; Sandweiss, J; Sangaline, E; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schmidke, W B; Schmitz, N; Seger, J; Seyboth, P; Shah, N; Shahaliev, E; Shanmuganathan, P V; Shao, M; Sharma, B; Shen, W Q; Shi, S S; Shou, Q Y; Sichtermann, E P; Singaraju, R N; Skoby, M J; Smirnov, D; Smirnov, N; Solanki, D; Sorensen, P; deSouza, U G; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stevens, J R; Stock, R; Strikhanov, M; Stringfellow, B; Suaide, A A P; Sumbera, M; Sun, X; Sun, X M; Sun, Y; Sun, Z; Surrow, B; Svirida, D N; Symons, T J M; de Toledo, A Szanto; Szelezniak, M A; Takahashi, J; Tang, A H; Tang, Z; Tarnowsky, T; Thomas, J H; Timmins, A R; Tlusty, D; Tokarev, M; Trentalange, S; Tribble, R E; Tribedy, P; Trzeciak, B A; Tsai, O D; Turnau, J; Ullrich, T; Underwood, D G; Van Buren, G; van Nieuwenhuizen, G; Vanfossen,, J A; Varma, R; Vasconcelos, G M S; Vasiliev, A N; Vertesi, R; Videbæk, F; Viyogi, Y P; Vokal, S; Vossen, A; Wada, M; Wang, F; Wang, G; Wang, H; Wang, J S; Wang, X L; Wang, Y; Webb, G; Webb, J C; Westfall, G D; Wieman, H; Wimsatt, G; Wissink, S W; Witt, R; Wu, Y F; Xiao, Z; Xie, W; Xin, K; Xu, H; Xu, J; Xu, N; Xu, Q H; Xu, Y; Xu, Z; Yan, W; Yang, C; Yang, Y; Ye, Z; Yepes, P; Yi, L; Yip, K; Yoo, I-K; Yu, N; Zawisza, Y; Zbroszczyk, H; Zha, W; Zhang, J B; Zhang, J L; Zhang, S; Zhang, X P; Zhang, Y; Zhang, Z P; Zhao, F; Zhao, J; Zhong, C; Zhu, X; Zhu, Y H; Zoulkarneeva, Y; Zyzak, M

    2014-01-01

    We report measurements of Upsilon meson production in p+p, d+Au, and Au+Au collisions using the STAR detector at RHIC. We compare the Upsilon yield to the measured cross section in p+p collisions in order to quantify any modifications of the yield in cold nuclear matter using d+Au data and in hot nuclear matter using Au+Au data separated into three centrality classes. Our p+p measurement is based on three times the statistics of our previous result. We obtain a nuclear modification factor for Upsilon(1S+2S+3S) in the rapidity range |y|<1 in d+Au collisions of R_dAu = 0.67 +/- 0.12 (stat.) +/- 0.04 (sys.) +/- 0.08 (pp sys.). A comparison with models including shadowing and initial state parton energy loss indicates the presence of additional cold-nuclear matter suppression. Similarly, in the top 10% most-central Au+Au collisions, we measure a nuclear modification factor of R_AA=0.36 +/- 0.09 (stat.) +/- 0.01 (sys.) +/- 0.04 (pp sys.), which is a larger suppression factor than that seen in cold nuclear matte...

  19. Identified particle distributions in pp and Au+Au collisions atsqrt sNN=200 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Adams, J.; Adler, C.; Aggarwal, M.M.; Ahammed, Z.; Amonett, J.; Anderson, B.D.; Anderson, M; Arkhipkin, D.; Averichev, G.S.; Badyal,S.K.; Balewski, J.; Barannikova, O.; Barnby, L.S.; Baudot, J.; Bekele,S.; Belaga, V.V.; Bellwied, R.; Berger, J.; Bezverkhny, B.I.; Bhardwaj,S.; Bhaskar, P.; Bhati, A.K.; Bichsel, H.; Billmeier, A.; Bland, L.C.; Blyth, C.O.; Bonner, B.E.; Botje, M.; Boucham, A.; Brandin, A.; Bravar,A.; Cadman, R.V.; Cai, X.Z.; Caines, H.; Calderon de la Barca Sanchez,M.; Carroll, J.; Castillo, J.; Castro, M.; Cebra, D.; Chaloupka, P.; Chattopadhyay, S.; Chen, H.F.; Chen, Y.; Chernenko, S.P.; Cherney, M.; Chikanian, A.; Choi, B.; Christie, W.; Coffin, J.P.; Cormier, T.M.; Cramer, J.G.; Crawford, H.J.; Das, D.; Das, S.; Derevschikov, A.A.; Didenko, L.; Dietel, T.; Dong, X.; Draper, J.E.; Du, F.; Dubey, A.K.; Dunin, V.B.; Dunlop, J.C.; Dutta Majumdar, M.R.; Eckardt, V.; Efimov,L.G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Faine, V.; Faivre, J.; Fatemi, R.; Filimonov, K.; Filip, P.; Finch, E.; Fisyak, Y.; Flierl, D.; Foley, K.J.; Fu, J.; Gagliardi, C.A.; Ganti, M.S.; Gutierrez, T.D.; Gagunashvili, N.; Gans, J.; Gaudichet, L.; Germain, M.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J.E.; Grachov, O.; Grigoriev, V.; Cronstal, S.; Grosnick, D.; Guedon, M.; Guertin, S.M.; Gupta, A.; Gushin, E.; Hallman, T.J.; Hardtke, D.; Harris,J.W.; Heinz, M.; Henry, T.W.; Heppelmann, S.; Herston, T.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffmann, G.W.; Horsley, M.; Huang, H.Z.; Huang,S.L.; Humanic, T.J.; Igo, G.; Ishihara, A.; Jacobs, P.; Jacobs, W.W.; Janik, M.; Johnson, I.; Jones, P.G.; Judd, E.G.; Kabana, S.; Kaneta, M.; Kaplan, M.; Keane, D.; Kiryluk, J.; Kisiel, A.; Klay, J.; Klein, S.R.; Klyachko, A.; Koetke, D.D.; Kollegger, T.; Konstantinov, A.S.; Kopytine,S.M.; Kotchenda, L.; Kovalenko, A.D.; Kramer, M.; Kravtsov, P.; Krueger,K.; Kuhn, C.; Kulikov, A.I.; Kumar, A.; et al.

    2003-10-06

    Transverse mass and rapidity distributions for charged pions, charged kaons, protons and antiprotons are reported for {radical}sNN = 200 GeV pp and Au+Au collisions at RHIC. The transverse mass distributions are rapidity independent within |y| < 0.5, consistent with a boost-invariant system in this rapidity interval. Spectral shapes and relative particle yields are similar in pp and peripheral Au+Au collisions and change smoothly to central Au+Au collisions. No centrality dependence was observed in the kaon and antiproton production rates relative to the pion production rate from medium-central to central collisions. Chemical and kinetic equilibrium model fits to our data reveal strong radial flow and relatively long duration from chemical to kinetic freeze-out in central Au+Au collisions. The chemical freeze-out temperature appears to be independent of initial conditions at RHIC energies.

  20. Enhanced strange baryon production in Au+Au collisions compared to p+p at sqrts = 200 GeV

    CERN Document Server

    Abelev, B I; Ahammed, Z; Anderson, B D; Arkhipkin, D; Averichev, G S; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Baumgart, S; Bekele, S; Belaga, V V; Bellingeri-Laurikainen, A; Bellwied, R; Benedosso, F; Betts, R R; Bhardwaj, S; Bhasin, A; Bhati, A K; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Blyth, S L; Bombara, M; Bonner, B E; Botje, M; Bouchet, J; Brandin, A V; Bravar, A; Burton, T P; Bystersky, M; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca-Sanchez, M; Callner, J; 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; Chung, S U; Coffin, J P; Cormier, T M; Cosentino, M R; Cramer, J G; Crawford, H J; Das, D; Das, S; Dash, S; Daugherity, M; De Moura, M M; Dedovich, T G; De Phillips, M; Derevshchikov, A A; Didenko, L; Dietel, T; Djawotho, P; Dogra, S M; Dong, X; Drachenberg, J L; Draper, J E; Du, F; Dunin, V B; Dunlop, J C; Dutta-Majumdar, 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, Yu; Fu, J; Gagliardi, C A; Gaillard, L; Ganti, M S; García-Solis, E; Ghazikhanian, V; Ghosh, P; Gorbunov, Y G; Gos, H; Grebenyuk, O; Grosnick, D; Guertin, S M; Guimaraes, K S F F; Gupta, N; 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; Hofman, D; Hollis, R; Horner, M J; Huang, H Z; Huang, S L; Hughes, E W; Humanic, T J; Igo, G; Iordanova, A; Jacobs, P; Jacobs, W W; Jakl, P; Jia, F; Jones, P G; Judd, E G; Kabana, S; Kang, K; Kapitan, J; Kaplan, M; Keane, D; Kechechyan, A; Kettler, D; Khodyrev, V Yu; Kim, B C; Kiryluk, J; Kisiel, A; Kislov, E M; Knospe, A G; Kocoloski, A; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kouchpil, V; Kowalik, K L; Kravtsov, P; Kravtsov, V I; Krüger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kurnadi, P; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; La Pointe, S; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Lee, C H; Lehocka, S; Le Vine, M J; Li, C; Li, Q; Li, Y; Lin, G; Lin, X; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, J; Liu, L; Liu, Z; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, J G; Ma, Y G; Magestro, D; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Melnik, Yu M; Meschanin, A; Millane, J; Miller, M L; Minaev, N G; Mioduszewski, S; Mironov, C; Mischke, A; Mishra, D K; Mitchell, J; Mohanty, B; Molnár, L; Moore, C F; Morozov, D A; Munhoz, M G; Nandi, B K; Nattrass, C; Nayak, T K; Nelson, J M; Nepali, N S; Netrakanti, P K; Nogach, L V; Nurushev, S B; Odyniec, Grazyna Janina; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Pachr, M; Pal, S K; Panebratsev, Yu A; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevozchikov, V; Perkins, C; Peryt, W; Phatak, S C; Planinic, M; Pluta, J; Poljak, N; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M V; Potrebenikova, E V; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Qattan, I A; Rakness, G; Raniwala, R; Raniwala, S; Ray, R L; Razin, S V; Reinnarth, J; Relyea, D; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M J; Sahoo, R; Sakuma, T; Salur, S; Sandweiss, J; Sarsour, M; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Schweda, K; Seger, J; Selyuzhenkov, I; Seyboth, P; Shabetai, A; Shahaliev, E; Shao, M; Sharma, M; Shen, W Q; Shimansky, S S; Sichtermann, E P; Simon, F; Singaraju, R N; Smirnov, N; Snellings, R; Sørensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Staszak, D; Stock, R; Stolpovsky, A; Strikhanov, M N; Stringfellow, B C; Suaide, A A P; Suarez, M C; Subba, N L; Sugarbaker, E R; Sumbera, M; Sun, Z; Surrow, B; Swanger, M; Symons, T J M; Szanto de Toledo, A; Takahashi, J; Tang, A H; Tarnowsky, T J; Thomas, J H; Timmins, A R; Timoshenko, S; Tokarev, M; Trainor, T A; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; Van der Kolk, N; Van Leeuwen, M; Van der Molen, A M; Varma, R; Vasilevski, I M; Vasilev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Waggoner, W T; Wang, F; Wang, G; Wang, J S; Wang, X L; Wang, Y; Watson, J W; Webb, J C; Westfall, G D; Wetzler, A; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wu, J; Xu, N; Xu, Q H; Xu, Z; Yepes, P; Yoo, I K; Yurevich, V I; Zhan, W; Zhang, H; Zhang, W M; Zhang, Y; Zhang, Z P; Zhao, Y; Zhong, C; Zhou, J; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N; Zuo, J X

    2007-01-01

    We report on the observed differences in production rates of strange and multi-strange baryons in Au+Au collisions at sqrts = 200 GeV compared to p+p interactions at the same energy. The yields in Au+Au collisions, when scaled by the number of participants, are larger than those measured in the p+p data. The magnitudes of the differences grow with the strangeness of the baryon and with increasing centrality. The enhancements of the Au+Au yields are close to those measured in sqrts = 17.3 GeV collisions. Further, when the binary scaled p+p pT spectra are compared to those of Au+Au the heavy-ion yields exceed binary scaling in the pT range 1 < pT< 4 GeV/c.

  1. Bonding, Luminescence, Metallophilicity in Linear Au3 and Au2Ag Chains Stabilized by Rigid Diphosphanyl NHC Ligands.

    Science.gov (United States)

    Ai, Pengfei; Mauro, Matteo; Gourlaouen, Christophe; Carrara, Serena; De Cola, Luisa; Tobon, Yeny; Giovanella, Umberto; Botta, Chiara; Danopoulos, Andreas A; Braunstein, Pierre

    2016-09-01

    The heterofunctional and rigid ligand N,N'-diphosphanyl-imidazol-2-ylidene (PCNHCP; P = P(t-Bu)2), through its phosphorus and two N-heterocyclic carbene (NHC) donors, stabilizes trinuclear chain complexes, with either Au3 or AgAu2 cores, and dinuclear Au2 complexes. The two oppositely situated PCNHCP (L) ligands that "sandwich" the metal chain can support linear and rigid structures, as found in the known tricationic Au(I) complex [Au3(μ3-PCNHCP,κP,κCNHC,κP)2](OTf)3 (OTf = CF3SO3; [Au3L2](OTf)3; Chem. Commun. 2014, 50, 103-105) now also obtained by transmetalation from [Ag3(μ3-PCNHCP,κP,κCNHC,κP)2](OTf)3 ([Ag3L2](OTf)3), or in the mixed-metal tricationic [Au2Ag(μ3-PCNHCP,κP,κCNHC,κP)2](OTf)3 ([Au2AgL2](OTf)3). The latter was obtained stepwise by the addition of AgOTf to the digold(I) complex [Au2(μ2-PCNHCP,κP,κCNHC)2](OTf)2 ([Au2L2](OTf)2). The latter contains two dangling P donors and displays fluxional behavior in solution, and the Au···Au separation of 2.8320(6) Å in the solid state is consistent with metallophilic interactions. In the solvento complex [Au3Cl2(tht)(μ3-PCNHCP,κP,κCNHC,κP)](OTf)·MeCN ([Au3Cl2(tht)L](OTf)·MeCN), which contains only one L and one tht ligand (tht = tetrahydrothiophene), the metal chain is bent (148.94(2)°), and the longer Au···Au separation (2.9710(4) Å) is in line with relaxation of the rigidity due to a more "open" structure. Similar features were observed in [Au3Cl2(SMe2)L](OTf)·2MeCN. A detailed study of the emission properties of [Au3L2](OTf)3, [Au3Cl2(tht)L](OTf)·MeCN, [Au2L2](OTf)2, and [Au2AgL2](OTf)3 was performed by means of steady state and time-resolved photophysical techniques. The complex [Au3L2](OTf)3 displays a bright (photoluminescence quantum yield = 80%) and narrow emission band centered at 446 nm with a relatively small Stokes' shift and long-lived excited-state lifetime on the microsecond timescale, both in solution and in the solid state. In line with the very narrow emission

  2. Charged hadron transverse momentum distributions in Au+Au collisions at √sNN=200 GeV

    Science.gov (United States)

    Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Lee, J. W.; 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.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Veres, G. I.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2004-01-01

    We present transverse momentum distributions of charged hadrons produced in Au+Au collisions at sNN=200 GeV. The spectra were measured for transverse momenta pT from 0.25 to 4.5 GeV/c in a pseudorapidity range of 0.2<η<1.4. The evolution of the spectra is studied as a function of collision centrality, from 65 to 344 participating nucleons. The results are compared to data from proton-antiproton collisions and Au+Au collisions at lower RHIC energies. We find a significant change of the spectral shape between proton-antiproton and semi-peripheral Au+Au collisions. Comparing semi-peripheral to central Au+Au collisions, we find that the yields at high pT exhibit approximate scaling with the number of participating nucleons, rather than scaling with the number of binary collisions.

  3. The effect of Au amount on size uniformity of self-assembled Au nanoparticles

    International Nuclear Information System (INIS)

    The self-assembled fabrication of nanostructure, a dreaming approach in the area of fabrication engineering, is the ultimate goal of this research. A finding was proved through previous research that the size of the self-assembled gold nanoparticles could be controlled with the mole ratio between AuCl4- and thiol. In this study, the moles of Au were fixed, only the moles of thiol were adjusted. Five different mole ratios of Au/S with their effect on size uniformity were investigated. The mole ratios were 1:1/16, 1:1/8, 1:1, 1:8, 1:16, respectively. The size distributions of the gold nanoparticles were analyzed by Mac-View analysis software. HR-TEM was used to derive images of self-assembled gold nanoparticles. The result reached was also the higher the mole ratio between AuCl4- and thiol the bigger the self-assembled gold nanoparticles. Under the condition of moles of Au fixed, the most homogeneous nanoparticles in size distribution derived with the mole ratio of 1:1/8 between AuCl4- and thiol. The obtained nanoparticles could be used, for example, in uniform surface nanofabrication, leading to the fabrication of ordered array of quantum dots

  4. Centrality dependence of direct photon production in (square root)S(NN) = 200 GeV Au + Au collisions.

    Science.gov (United States)

    Adler, S S; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Alexander, J; Amirikas, R; Aphecetche, L; Aronson, S H; Averbeck, R; Awes, T C; Azmoun, R; Babintsev, V; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bazilevsky, A; Belikov, S; Berdnikov, Y; Bhagavatula, S; Boissevain, J G; Borel, H; Borenstein, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Chai, J-S; Chand, P; Chang, W C; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J; Choudhury, R K; Chujo, T; Cianciolo, V; Cobigo, Y; Cole, B A; Constantin, P; d'Enterria, D; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Devismes, A; Dietzsch, O; Drapier, O; Drees, A; du Rietz, R; Durum, A; Dutta, D; Efremenko, Y V; El Chenawi, K; Enokizono, A; En'yo, H; Esumi, S; Ewell, L; Fields, D E; Fleuret, F; Fokin, S L; Fox, B D; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Gogiberidze, G; Gonin, M; Gosset, J; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Perdekamp, M Grosse; Guryn, W; Gustafsson, H-A; Hachiya, T; Haggerty, J S; Hamagaki, H; Hansen, A G; Hartouni, E P; Harvey, M; Hayano, R; Hayashi, N; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Holzmann, W; Homma, K; Hong, B; Hoover, A; Ichihara, T; Ikonnikov, V V; Imai, K; Isenhower, D; Ishihara, M; Issah, M; Isupov, A; Jacak, B V; Jang, W Y; Jeong, Y; Jia, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kametani, S; Kamihara, N; Kang, J H; Kapoor, S S; Katou, K; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, D W; Kim, E; Kim, G-B; Kim, H J; Kistenev, E; Kiyomichi, A; Kiyoyama, K; Klein-Boesing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kopytine, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kuberg, C H; Kurita, K; Kuroki, Y; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Ladygin, V; Lajoie, J G; Lebedev, A; Leckey, S; Lee, D M; Lee, S; Leitch, M J; Li, X H; Lim, H; Litvinenko, A; Liu, M X; Liu, Y; Maguire, C F; Makdisi, Y I; Malakhov, A; Manko, V I; Mao, Y; Martinez, G; Marx, M D; Masui, H; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Messer, F; Miake, Y; Milan, J; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagle, J L; Nakamura, T; Nandi, B K; Nara, M; Newby, J; Nilsson, P; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Ono, M; Onuchin, V; Oskarsson, A; Otterlund, I; Oyama, K; Ozawa, K; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, J; Parmar, A; Pate, S F; Peitzmann, T; Peng, J-C; Peresedov, V; Pinkenburg, C; Pisani, R P; Plasil, F; Purschke, M L; Purwar, A K; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosnet, P; Ryu, S S; Sadler, M E; Saito, N; Sakaguchi, T; Sakai, M; Sakai, S; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Semenov, V; Seto, R; Shaw, M R; Shea, T K; Shibata, T-A; Shigaki, K; Shiina, T; Silva, C L; Silvermyr, D; Sim, K S; Singh, C P; Singh, V; Sivertz, 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; Sullivan, J P; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarján, P; Tepe, J D; Thomas, T L; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tuli, S K; Tydesjö, H; Tyurin, N; van Hecke, H W; Velkovska, J; Velkovsky, M; Veszprémi, V; Villatte, L; Vinogradov, A A; Volkov, M A; Vznuzdaev, E; Wang, X R; Watanabe, Y; White, S N; Wohn, F K; Woody, C L; Xie, W; Yang, Y; Yanovich, A; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zhou, S J; Zolin, L

    2005-06-17

    The first measurement of direct photons in Au + Au collisions at (square root)S(NN) = 200 GeV is presented. The direct photon signal is extracted as a function of the Au + Au collision centrality and compared to next-to-leading order perturbative quantum chromodynamics calculations. The direct photon yield is shown to scale with the number of nucleon-nucleon collisions for all centralities. PMID:16090462

  5. Centrality Dependence of Direct Photon Production in √(SNN)=200 GeV Au+Au Collisions

    International Nuclear Information System (INIS)

    The first measurement of direct photons in Au+Au collisions at √(sNN)=200 GeV is presented. The direct photon signal is extracted as a function of the Au+Au collision centrality and compared to next-to-leading order perturbative quantum chromodynamics calculations. The direct photon yield is shown to scale with the number of nucleon-nucleon collisions for all centralities

  6. Au/Pd core-shell nanoparticles with varied hollow Au cores for enhanced formic acid oxidation

    OpenAIRE

    Hsu, Chiajen; Huang, Chienwen; Hao, Yaowu; Liu, Fuqiang

    2013-01-01

    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 ...

  7. 197Au Moessbauer studies of gold components and γ-ray irradiation effect

    International Nuclear Information System (INIS)

    The 197Au Moessbauer spectra of Au(I) (tmH2) and [Au(III)(tpp)][Au(III)Cl4] were measured. The isomer shifts and quadrupole splittings indicate that the gold compounds are in typical aurous and auric state, respectively. While no γ-ray irradiation effect was found in Au(tmH2), a novel Au(I) species was observed in γ-irradiated [Au(tpp)][AuCl4] by means of Moessbauer spectroscopy. (author)

  8. 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...

  9. Dynamics study of green AuNP formation and their basis for Au-Pt core-shell nanostructure synthesis

    DEFF Research Database (Denmark)

    Engelbrekt, Christian; Seselj, Nedjeljko; Ulstrup, Jens; Zhang, Jingdong

    details of nanoparticle formation has been developed employing readily available electrochemical and optical techniques. The aim is to understand which parameters control the growth and shape and at which stages of the synthesis. The gold nanoparticles (AuNPs) studied are further used as seeds for size...... controlled AuNPs and Au - Pt core - shell NPs with an atomically thin Pt shell...

  10. Spectra and ratios of identified particles in Au+Au and d+Au collisions at sqrt(s_NN)=200 GeV

    OpenAIRE

    Adare, A.; Afanasiev, S.; Aidala, C.; Ajitanand, N. N.; Akiba, Y; Al-Bataineh, H.; Alexander, J.; Angerami, A.(Nevis Laboratory, Columbia University, Irvington, NY, U.S.A.); Aoki, K.; Apadula, N.; Aramaki, Y.; Atomssa, E. T.; Averbeck, R.; Awes, T. C.; Azmoun, B.

    2013-01-01

    The transverse momentum (p_T) spectra and ratios of identified charged hadrons (\\pi^+/-, K^+/-, p, p^bar) produced in sqrt(s_NN)=200 GeV Au+Au and d+Au collisions are reported in five different centrality classes for each collision species. The measurements of pions and protons are reported up to p_T=6 GeV/c (5 GeV/c), and the measurements of kaons are reported up to p_T=4 GeV/c (3.5 GeV/c) in Au+Au (d+Au) collisions. In the intermediate p_T region, between 2--5 GeV/c, a significant enhanceme...

  11. Di-Hadron Correlations with Identified Leading Hadrons in 200 GeV Au+Au and d+Au Collisions at STAR

    CERN Document Server

    Abdelwahab, N M; Adkins, J K; Agakishiev, G; Aggarwal, M M; Ahammed, Z; Alekseev, I; Alford, J; Anson, C D; Aparin, A; Arkhipkin, D; Aschenauer, E C; Averichev, G S; Banerjee, A; Beavis, D R; Bellwied, R; Bhasin, A; Bhati, A K; Bhattarai, P; Bielcik, J; Bielcikova, J; Bland, L C; Bordyuzhin, I G; Borowski, W; Bouchet, J; Brandin, A V; Brovko, S G; Bültmann, S; Bunzarov, I; Burton, T P; Butterworth, J; Caines, H; Sánchez, M Calderón de la Barca; Campbell, J M; Cebra, D; Cendejas, R; Cervantes, M C; Chaloupka, P; Chang, Z; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, L; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Chwastowski, J; Codrington, M J M; Contin, G; Cramer, J G; Crawford, H J; Cui, X; Das, S; Leyva, A Davila; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; Derevschikov, A A; de Souza, R Derradi; di Ruzza, B; Didenko, L; Dilks, C; Ding, F; Djawotho, P; Dong, X; Drachenberg, J L; Draper, J E; Du, C M; Dunkelberger, L E; Dunlop, J C; Efimov, L G; Engelage, J; Engle, K S; Eppley, G; Esha, R; Eun, L; Evdokimov, O; Eyser, O; Fatemi, R; Fazio, S; Fedorisin, J; Filip, P; Fisyak, Y; Flores, C E; Gagliardi, C A; Gangadharan, D R; Garand, D; Geurts, F; Gibson, A; Girard, M; Gliske, S; Greiner, L; Grosnick, D; Gunarathne, D S; Guo, Y; Gupta, A; Gupta, S; Guryn, W; Haag, B; Hamad, A; Hamed, A; Han, L-X; Haque, R; Harris, J W; Heppelmann, S; Hirsch, A; Hoffmann, G W; Hofman, D J; Horvat, S; Huang, B; Huang, H Z; Huang, X; Huck, P; Humanic, T J; Igo, G; Jacobs, W W; Jang, H; Judd, E G; Kabana, S; Kalinkin, D; Kang, K; Kauder, K; Ke, H W; Keane, D; Kechechyan, A; Kesich, A; Khan, Z H; Kikola, D P; Kisel, I; Kisiel, A; Koetke, D D; Kollegger, T; Konzer, J; Koralt, I; Kosarzewski, L K; Kotchenda, L; Kraishan, A F; Kravtsov, P; Krueger, K; Kulakov, I; Kumar, L; Kycia, R A; Lamont, M A C; Landgraf, J M; Landry, K D; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; Li, C; Li, W; Li, X; Li, Y; Li, Z M; Lisa, M A; Liu, F; Ljubicic, T; Llope, W J; Lomnitz, M; Longacre, R S; Luo, X; Ma, G L; Ma, Y G; Mahapatra, D P; Majka, R; Margetis, S; Markert, C; Masui, H; Matis, H S; McDonald, D; McShane, T S; Minaev, N G; Mioduszewski, S; Mohanty, B; Mondal, M M; Morozov, D A; Mustafa, M K; Nandi, B K; Nasim, Md; Nayak, T K; Nelson, J M; Nigmatkulov, G; Nogach, L V; Noh, S Y; Novak, J; Nurushev, S B; Odyniec, G; Ogawa, A; Oh, K; Ohlson, A; Okorokov, V; Oldag, E W; Olvitt, D L; Page, B S; Pan, Y X; Pandit, Y; Panebratsev, Y; Pawlak, T; Pawlik, B; Pei, H; Perkins, C; Pile, P; Planinic, M; Pluta, J; Poljak, N; Poniatowska, K; Porter, J; Poskanzer, A M; Pruthi, N K; Przybycien, M; Putschke, J; Qiu, H; Quintero, A; Ramachandran, S; Raniwala, R; Raniwala, S; Ray, R L; Riley, C K; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Ross, J F; Roy, A; Ruan, L; Rusnak, J; Rusnakova, O; Sahoo, N R; Sahu, P K; Sakrejda, I; Salur, S; Sandacz, A; Sandweiss, J; Sangaline, E; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schmidke, W B; Schmitz, N; Seger, J; Seyboth, P; Shah, N; Shahaliev, E; Shanmuganathan, P V; Shao, M; Sharma, B; Shen, W Q; Shi, S S; Shou, Q Y; Sichtermann, E P; Simko, M; Skoby, M J; Smirnov, D; Smirnov, N; Solanki, D; Sorensen, P; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stevens, J R; Stock, R; Strikhanov, M; Stringfellow, B; Sumbera, M; Sun, X; Sun, X M; Sun, Y; Sun, Z; Surrow, B; Svirida, D N; Symons, T J M; Szelezniak, M A; Takahashi, J; Tang, A H; Tang, Z; Tarnowsky, T; Thomas, J H; Timmins, A R; Tlusty, D; Tokarev, M; Trentalange, S; Tribble, R E; Tribedy, P; Trzeciak, B A; Tsai, O D; Turnau, J; Ullrich, T; Underwood, D G; Van Buren, G; van Nieuwenhuizen, G; Vandenbroucke, M; Vanfossen,, J A; Varma, R; Vasconcelos, G M S; Vasiliev, A N; Vertesi, R; Videbæk, F; Viyogi, Y P; Vokal, S; Vossen, A; Wada, M; Wang, F; Wang, G; Wang, H; Wang, J S; Wang, X L; Wang, Y; Webb, G; Webb, J C; Wen, L; Westfall, G D; Wieman, H; Wissink, S W; Wu, Y F; Xiao, Z; Xie, W; Xin, K; Xu, H; Xu, J; Xu, N; Xu, Q H; Xu, Y; Xu, Z; Yan, W; Yang, C; Yang, Y; Ye, Z; Yepes, P; Yi, L; Yip, K; Yoo, I-K; Yu, N; Zbroszczyk, H; Zha, W; Zhang, J B; Zhang, J L; Zhang, S; Zhang, X P; Zhang, Y; Zhang, Z P; Zhao, F; Zhao, J; Zhong, C; Zhu, X; Zhu, Y H; Zoulkarneeva, Y; Zyzak, M

    2014-01-01

    The STAR collaboration presents new two-dimensional di-hadron correlations with leading hadrons in 200 GeV central Au+Au and minimum bias d+Au collisions to explore hadronization mechanisms in the quark gluon plasma. The enhancement of the jet-like yield for leading pions in Au+Au data with respect to the d+Au reference and the absence of enhancement for leading non-pions (protons and kaons) are discussed within the context of quark recombination. The correlated yield at large angles, specifically in the \\emph{ridge region}, is significantly higher for leading non-pions than pions. The consistencies of the constituent quark scaling, azimuthal harmonic model and a mini-jet modification model description of the data are tested, providing further constraints on hadronization.

  12. Di-hadron correlations with identified leading hadrons in 200 GeV Au+Au and d+Au collisions at STAR

    Directory of Open Access Journals (Sweden)

    L. Adamczyk

    2015-12-01

    Full Text Available The STAR Collaboration presents for the first time two-dimensional di-hadron correlations with identified leading hadrons in 200 GeV central Au+Au and minimum-bias d+Au collisions to explore hadronization mechanisms in the quark gluon plasma. The enhancement of the jet-like yield for leading pions in Au+Au data with respect to the d+Au reference and the absence of such an enhancement for leading non-pions (protons and kaons are discussed within the context of a quark recombination scenario. The correlated yield at large angles, specifically in the ridge region, is found to be significantly higher for leading non-pions than pions. The consistencies of the constituent quark scaling, azimuthal harmonic model and a mini-jet modification model description of the data are tested, providing further constraints on hadronization.

  13. Thermal desorption of Au from W(001) surface

    CERN Document Server

    Blaszczyszyn, R; Godowski, P J

    2002-01-01

    Adsorption of Au on W(001) at 450 K up to multilayer structures was investigated. Temperature programmed desorption technique was used in determination of coverage dependent desorption energy (region up to one monolayer). Results were discussed in terms of competitive interactions of Au-Au and Au-W atoms. Simple procedure for prediction of faceting behavior on the interface, basing on the desorption data, was postulated. It was deduced that the Au/W(001) interface should not show faceting tendency after thermal treatment. (author)

  14. Thermal Desorption of Au from W(001) Surface

    Science.gov (United States)

    Błaszczyszyn, R.; Chrzanowski, J.; Godowski, P. J.

    2000-12-01

    Adsorption of Au on W(001) at 450 K up to multilayer structures was investigated. Temperature programmed desorption technique was used in determination of coverage dependent desorption energy (region up to one monolayer). Results were discussed in terms of competitive interactions of Au--Au and Au--W atoms. Simple procedure for prediction of faceting behavior on the interface, basing on the desorption data, was postulated. It was deduced that the Au/W(001) interface should not show faceting tendency after thermal treatment.

  15. Superconducting Au-YBa2Cu3O7 composites

    International Nuclear Information System (INIS)

    Superconducting Au-YBa2Cu3O7 composites have been fabricated over a Au volume fraction range of 0--100%. Microstructure measurement indicates that Au and YBa2Cu3O7 form well-separated phases. The superconducting transition temperature T/sub c/ was found unaffected by the presence of Au. The composites exhibit low normal state resistivity and much improved ductility. The results suggest that Au is an excellent metal host for making ultrafine YBa2Cu3O7 granular solids

  16. "Dealloying" Phase Separation during Growth of Au on Ni(110)

    DEFF Research Database (Denmark)

    Nielsen, L. Pleth; Besenbacher, Flemming; Stensgaard, I.;

    1995-01-01

    Combined scanning tunneling microscopy and ion-scattering studies have revealed a new "dealloying" phase transition during the growth of Au on Ni(110). The Au atoms, which initially alloy into the Ni(110) surface, phase separate into a vacancy-stabilized Au dimer-trimer chain structure at Au...... coverages larger than 0.4 monolayer. Using the effective-medium theory, we show that the resulting structure as well as the physical mechanism responsible for the phase transition are closely related to the surface stress induced by the substituted Au....

  17. First results on d+Au collisions from PHOBOS

    Science.gov (United States)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Noell, A.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sawicki, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Teng, R.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Veres, G. I.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.; Zhang, J.

    2004-02-01

    We have measured transverse momentum distributions of charged hadrons produced in d+Au collisions at √SNN = 200 GeV, in the range 0.25 < pT < 6.0 GeV/c. With increasing collision centrality, the yield at high transverse momenta increases more rapidly than the overall particle density, leading to a strong modification of the spectral shape. This change in spectral shape is qualitatively different from observations in Au+Au collisions at the same energy. The results provide important information for discriminating between different models for the suppression of high-pT hadrons observed in Au+Au collisions.

  18. On line nuclear orientation of Au isotopes at KOOL

    International Nuclear Information System (INIS)

    The low temperature nuclear orientation facility KOOL was used for a systematical study of the very neutron-deficient Au isotopes where the on-line technique is compulsory due to the short lifetimes involved. The measurement of the magnetic moment of the 4.6 min 189Au 11/2- isomer, a preliminary result on the same state in tsub(1/2) = 0.9 sec 191Au and the moment value of the tsub(1/2) = 10.7 min 186Au 3- ground state is reported. Several spins and mixing ratios in 189Pt, 186Pt and 191Au have been determined as well

  19. Photoswitchable Faraday effect in EuS-Au nanosystems

    Energy Technology Data Exchange (ETDEWEB)

    Kawashima, Akira; Nakanishi, Takayuki; Kitagawa, Yuichi; Fushimi, Koji; Hasegawa, Yasuchika [Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, North-13 West-8, Kita-ku, 060-8628, Sapporo (Japan)

    2016-01-15

    Effective photoswitchable europium sulfide nanocrystals with gold nanoparticles using dithiol (DDT: 1,10-decanedithiol) joint molecules, EuS-Au nanosystems, are demonstrated. The TEM image indicates the formation of EuS-Au nanosystems composed of cube-shaped EuS nanocrystals and spherical Au nanoparticles. Under visible-light irradiation, a drastic change of absorption band of EuS-Au nanosystems at around 600 nm was observed. The Faraday effects of EuS-Au nanosystems were estimated using magnetic circular dichroism (MCD) measurements. The effective change of the MCD spectra of EuS-Au nanosystems under visible-light irradiation was successfully observed at around 670 nm for the first time. The effective reversible changes in MCD spectra with the alternative irradiation cycles of visible light (>440 nm) and dark are also presented. The decrease rate of rotation angle at 670 nm of EuS-Au nanosystems is larger than that of absorbance. These results indicate that the effective change of MCD spectra of EuS-Au nanosystems would be dominated not only by a drastic change of absorption band related to enhanced LSPR of Au nanoparticles but also by specific interaction between EuS and Au in nanosystem under irradiation. Illustration of photoswitch and TEM image of EuS-Au nanosystems. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Synthesis of SERS active Au nanowires in different noncoordinating solvents

    International Nuclear Information System (INIS)

    Au nanowires with length up to micrometers were synthesized through a simple and one-pot solution growth method. HAuCl4 was reduced in a micellar structure formed by 1-octadecylamine and oleic acid in hexane, heptane, toluene and chloroform, respectively. As the non-polarity of noncoordinating solvents can affect the nucleation and growth rates of Au nanostructures, Au nanowires with different diameters could be obtained by changing the noncoordinating solvents in the synthetic process. The influences of the solvents on the morphology of Au nanowires were systematically studied. When using hexane as reaction solvent, the product turned to be high portion of Au nanowires with more uniform size than the others. Furthermore, surface-enhanced Raman scattering (SERS) spectrum of 2-thionaphthol was obtained on the Au nanowire-modified substrate, indicating that the as-synthesized Au nanowires have potential for highly sensitive optical detection application.

  1. Ion beam processing of Au nanowires

    International Nuclear Information System (INIS)

    In nanoelectronics a nanowire forms an elemental building block enabling a charge transfer in complex nanostructures. Ion beam etching has been applied for downsizing of prefabricated Au nanowires in the sub-50 nm linewidth regime, aiming at achieving effective cross sections of less than 10 nm. Low energy Ar+ and Ga+ ions were employed for dry ion beam etching of Au nanowires. Nanometer-precise gradual downsizing to an effective diameter as small as 9 nm has been achieved when using Ar+ ions. In contrast, the chemical nature of Ga and its surface condensation into a nanosized phase turned out to act destructively on the nanowires' morphology, hampering the process of downsizing. In the surface nanocondensate Ga was found to coexist in both solid and liquid states, exhibiting polymorphism and peculiar dynamics under ion irradiation.

  2. Chapitre 1. De la marge au centre

    OpenAIRE

    Guinle, Francis

    2011-01-01

    Une des traductions possibles du terme sīra est « itinéraire de vie ». Le mot « itinéraire » me semble tout à fait approprié car il peut s’appliquer à plusieurs aspects du récit : les itinéraires géographiques, qu’ils soient pris au sens propre ou au sens métaphorique, les itinéraires de la quête initiatique, les itinéraires que suivent certains cycles d’épisodes pour s’imbriquer les uns dans les autres, les itinéraires détournés, etc. Qu’il s’agisse de l’itinéraire de Baybarṣ dans sa montée ...

  3. 2D chemistry on Au(111) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rauls, Eva; Blankenburg, Stephan; Schmidt, Wolf Gero [Theoretische Physik, Universitaet Paderborn (Germany)

    2009-07-01

    The design of functional two-dimensional molecular networks has become an area of intense research. The constraint to 2 in contrast to the availability of 3 dimensions has a large impact on many chemical reactions. Chemical reactions between surface adsorbed molecules may lead to products very different from those obtained in solutions or the gas phase. The imide formation between a diaminoterphenyl (DATP) and a PTCDA molecule is one very interesting example in this respect. In scanning tunneling microscopy (STM) experiments, it has been observed that the Au surface changes both the reaction path and the reaction product compared to 3D. In order to understand these experimental observations, we have studied the chemical reactions both in solution and on the Au(111) surface by density-functional theory calculations in the generalized-gradient approximation.

  4. Materiaux composites courants: Tenue au feu

    OpenAIRE

    Croquette, Jean; Baudin, M.

    1992-01-01

    Dans le cadre du projet national "Composites navals", plusieurs séries d'essais de tenue au feu ont été effectuées sur des tuyauteries en verre époxy bobiné et divers matériaux de structure monolithiques et sandwiches employés couramment en construction navale. Cette communication décrit les matériaux testés et les procédures d'essais employées pour évaluer la réaction au feu: inflammabilité par l'essai à l'épiradiateur (classement M), émission de fumées (classement F), ainsi que la résistanc...

  5. De l’individu postcommuniste au citoyen

    OpenAIRE

    Anna Krasteva

    2013-01-01

    L’article analyse le paradoxe de la conception communiste du citoyen engagé : au niveau idéologique, citoyenneté et engagement sont intrinsèquement liés, au niveau politique ils sont souvent radicalement dissociés. Le citoyen communiste est plus engagé que citoyen. La citoyenneté était dépourvue de plusieurs de ses attributs : de la jouissance de la loi qui établit « l’égalité arithmétique » et minorise les maîtres ; de la citoyenneté active – civile et politique – pour ne jouir que la protec...

  6. D. Marguerat (dir.), Introduction au Nouveau Testament

    OpenAIRE

    Morgen, Michèle

    2015-01-01

    L’introduction au Nouveau Testament dirigée par D. Marguerat est rédigée par une dizaine d’exégètes (C. Combet-Galland, E. Cuvillier, A. Dettwiler, R. Dupont-Roc, J.-D. Kaestli, D. Marguerat, Y. Redalié, J. Schlosser, F. Vouga, J. Zumstein) ; chacun propose une introduction détaillée d’un ou de plusieurs livres bibliques dont il est le spécialiste. E. Steffek a mis au point le travail d’édition, comme dans les éditions précédentes. L’ouvrage en est en effet à sa troisième édition, ce qui soul...

  7. Tunable VO2/Au hyperbolic metamaterial

    Science.gov (United States)

    Prayakarao, S.; Mendoza, B.; Devine, A.; Kyaw, C.; van Dover, R. B.; Liberman, V.; Noginov, M. A.

    2016-08-01

    Vanadium dioxide (VO2) is known to have a semiconductor-to-metal phase transition at ˜68 °C. Therefore, it can be used as a tunable component of an active metamaterial. The lamellar metamaterial studied in this work is composed of subwavelength VO2 and Au layers and is designed to undergo a temperature controlled transition from the optical hyperbolic phase to the metallic phase. VO2 films and VO2/Au lamellar metamaterial stacks have been fabricated and studied in electrical conductivity and optical (transmission and reflection) experiments. The observed temperature-dependent changes in the reflection and transmission spectra of the metamaterials and VO2 thin films are in a good qualitative agreement with theoretical predictions. The demonstrated optical hyperbolic-to-metallic phase transition is a unique physical phenomenon with the potential to enable advanced control of light-matter interactions.

  8. Preparation of Au, U films and Au/U/Au multilayer film by ultra-high vacuum pulsed-laser deposition

    International Nuclear Information System (INIS)

    Metallic uranium has the characteristic of high efficiency of laser to X-ray energy conversion The ultra-high vacuum pulsed-laser deposition (PLD) system was used to prepare Au film, U film and Au/U/Au multilayer film on single Si(100) substrate to prevent the oxidation of uranium. The SEM pictures show that there are spherical metal droplets with diameters less than several microns on the Au and U film surface prepared by PLD under present technology. The surface roughness Ra of less droplet region is less than 1 nm, and the big droplet containing region is less than 15 nm. The amount of droplet on U film surface is much more than Au film surface under the same -deposition condition. The Au/U/Au multilayer film with thickness about 195 nm and Rq between 0.3-1.5 nm was prepared after PLD technology optimization. AES depth profile results reveal that the oxygen content in Au/U/Au multilayer film is less than 5% (atomic percentage), and uranium remains in metal chemical state. It may be effective to reduce the number and size of droplets by reducing the laser power, increasing the distance of target from the substrate and appropriately rising the substrate temperature. (authors)

  9. Transition probability studies in 175Au

    OpenAIRE

    Grahn, Tuomas; Watkins, H.; Joss, David; Page, Robert; Carroll, R. J.; Dewald, A.; Greenlees, Paul; Hackstein, M.; Herzberg, Rolf-Dietmar; Jakobsson, Ulrika; Jones, Peter; Julin, Rauno; Juutinen, Sakari; Ketelhut, Steffen; Kröll, Th

    2013-01-01

    Transition probabilities have been measured between the low-lying yrast states in 175Au by employing the recoil distance Doppler-shift method combined with the selective recoil-decay tagging technique. Reduced transition probabilities and magnitudes of transition quadrupole moments have been extracted from measured lifetimes allowing dramatic changes in nuclear structure within a low excitation-energy range to probed. The transition quadrupole moment data are discussed in terms...

  10. Les entreprises au Royaume-Uni

    OpenAIRE

    Appay, Beatrice

    1987-01-01

    This chapter of the book "Formations et emplois qualifiés. Les transformations dans le Bâtiment en France et au Royaume-Uni" analyses management strategies and organisational changes during a period of continuous crisis. The concept of cascading subcontracting (sous-traitance en cascade) introduced here encapsulates a new phenomenon observed simultaneously in the ever changing organisation of work between and within the firms. This is an important result of a research based on a 34 firm monog...

  11. Auditoire et espace public au CERN

    OpenAIRE

    Schaerrer, Lorène

    1997-01-01

    Un bâtiment comprenant un auditoire de 1200 places, un musée lié à la recherche nucléaire et des surfaces d'exposition. Le bâtiment est en relation avec le nouveau tram périurbain; en particulier par le biais d'un parking d'échange, qui peut servir au bât

  12. Jet structure of baryon excess in Au+Au collisions at √(sNN)=200 GeV

    International Nuclear Information System (INIS)

    Two particle correlations between identified meson and baryon trigger particles with 2.5TT charged hadrons have been measured at midrapidity by the PHENIX experiment at RHIC in p+p,d+Au, and Au+Au collisions at √(sNN)=200 GeV. In noncentral Au+Au collisions, the probability of finding a hadron near in azimuthal angle to the trigger particles is almost identical for mesons and baryons and significantly higher than in p+p collisions. The associated yields for trigger baryons decrease in the most central collisions, consistent with some baryon production by thermal recombination in addition to hard scattering

  13. Analysis of the residual linewidth in electron-paramagnetic resonance of AuEr and AuYb

    Science.gov (United States)

    Spalden, Y. von; Baberschke, K.

    1981-04-01

    For single crystals of AuEr and polycrystalline AuYb the residual EPR linewidth due to inhomogeneous broadening is analyzed. Angular dependent experiments show uniquely that the main contribution is due to internal strain rather than to dipolar interaction. The independent experiments for AuEr and AuYb yield a consistent set of parameters but show a dipolar contribution two to three times smaller than calculated. An explanation for this is given. The very precise determination of Hres yields |Δg | = |ρJ1| AuEr, a vanishing g-shift.

  14. Charge transport through O-deficient Au-MgO-Au junctions

    KAUST Repository

    Fadlallah, M. M.

    2009-12-29

    Metal-oxide heterostructures have been attracting considerable attention in recent years due to various technological applications. We present results of electronic structure and transport calculations for the Au-MgO-Au (metal-insulator-metal) heterostructure based on density-functional theory and the nonequilibrium Green’s functions method. The dependence of the conductance of the heterostructure on the thickness of the MgO interlayer and the interface spacing is studied. In addition, we address the effects of O vacancies. We observe deviations from an exponentially suppressed conductance with growing interlayer thickness caused by Au-O chemical bonds. Electronic states tracing back to O vacancies can increase the conductance. Furthermore, this effect can be enhanced by enlarging the interface spacing as the vacancy induced Mg states are shifted toward the Fermi energy.

  15. Decontamination by fractional distillation of a radioactive mixture of perchlorethylene, bitumen, and sludges from chemical co-precipitations; Decontamination par distillation fractionnee d'un melange radioactif constitue par du perchlorethylene, du bitume et des boues de coprecipitation chimique

    Energy Technology Data Exchange (ETDEWEB)

    Lefillatre, G.; Hullo, R. [Commissariat a l' Energie Atomique, Chusclan (France). Centre de Production de Plutonium de Marcoule

    1969-07-01

    It is not possible to incinerate the contaminated organic waste containing chlorine, produced at the Marcoule Centre. The only valid method for these solvents of average activity is fractional distillation. This report presents a pilot fractional distillation plant designed for decontaminating the residual solvents produced by the Centre's Waste Processing Station. These contaminated solvents come from the decontamination of a screw extrusion apparatus with perchlorethylene; this equipment is used for coating the radioactive sludges with bitumen. The pilot plant operates discontinuously and is used to decontaminate the perchlorethylene, to separate the perchlorethylene from the water, and to process the distillation residue. The electrically heated boiler is fitted with a removable base in the form of a disposable container. The installations decontamination factor is 3.4 x 10{sup 6} when solvents with a specific activity of 0.23 Ci/m{sup 3} are used. The average flow-rate for a distillation run is 10 l/hr at atmospheric pressure, and 21 l/hr at a residual pressure of 40 torr. The decontamination factor for the installation is better at atmospheric pressure than in a vacuum. (authors) [French] Les effluents organiques contamines chlores du Centre de Marcoule ne peuvent etre incineres. Le seul mode de traitement qui s'impose pour ces solvants de moyenne activite s'avere etre la distillation fractionnee. Ce rapport presente une installation pilote de distillation fractionnee qui a ete concue pour decontaminer des solvants residuaires provenant de la Station de Traitement des Effluents du Centre. Ces solvants contamines resultent de la decontamination au moyen de perchlorethylene d'une extrudeuse a vis servant a l'enrobage par le bitume des boues radioactives de cette station. L'installation pilote fonctionne en discontinu et assure a la fois la decontamination du perchlorethylene, la separation du perchlorethylene et de l'eau et le

  16. Synthesis and characterization of Au@Pt nanoparticles

    Institute of Scientific and Technical Information of China (English)

    ZHAO Dan; WU Gang; XU Boqing

    2005-01-01

    Aucore-Ptshell (Au@Pt) nanoparticles were synthesized at room temperature by reducing K2PtCl6 with hydrogen in the solution containing Au colloids and polyvinylpyrrolidone (PVP). The particles obtained were characterized with UV-Vis, TEM and XPS techniques. UV-Vis spectra show that the surface plasmon absorption feature of Au colloids is significantly reduced with increasing the amount of reduced Pt. TEM images that the metals are found always appear as spherical nanoparticles and their sizes grow apparently due to the reduction of PtCl62- ions, indicating that Pt is deposited from solution onto Au particle surface and forms a Pt-layer with uniform thickness. In the XPS spectra, the signals of Au metal decrease due to the reductive deposition of Pt on the surface of the Au colloids. UV-Vis and XPS data are consistent in showing that when the amount of Pt in the AuPt colloids is increased to reach an overall atomic ratio of Pt/Au=2, the Pt deposits form a shell covering completely the surface of Au particles, demonstrating the core-shell structure of the synthesized AuPt particles.

  17. PARTON STRUCTURE THROUGH TWO PARTICLE CORRELATIONS IN AU-AU AT RHIC.

    Energy Technology Data Exchange (ETDEWEB)

    LONGACRE,R.S.

    1999-10-23

    A method for determining the presence of partonic scattering through two-particle correlations is developed and applied to models which have jets and mini-jets in them. We only consider the correlation of mid-rapidity particles because they will be easily measured in large numbers at RHIC. The level of two-particle correlations will be a direct measure of how dense a system is made in Au-Au collisions at RHIC. The STAR TPC will be ideal for making these measurements in the first year of running.

  18. Observation of anisotropic event shapes and transverse flow in ultrarelativistic Au+Au collisions

    International Nuclear Information System (INIS)

    Event shapes for Au + Au collisions at 11.4 GeV/c per nucleon were studied over nearly the full solid angle with the E877 apparatus. The analysis was performed by Fourier expansion of azimuthal distributions of the transverse energy (ET) measured in different pseudorapidity intervals. For semicentral collisions a pronounced event anisotropy is identified with a clear forward-backward anticorrelation. In the forward pseudorapidity interval up to 9% of the ET is in a directed component. The signal decreases for peripheral and very central collisions

  19. Net charge fluctuations in Au + Au interactions at sqrt[s(NN)]=130 GeV.

    Science.gov (United States)

    Adcox, K; Adler, S S; Ajitanand, N N; Akiba, Y; Alexander, J; Aphecetche, L; Arai, Y; Aronson, S H; Averbeck, R; Awes, T C; Barish, K N; Barnes, P D; Barrette, J; Bassalleck, B; Bathe, S; Baublis, V; Bazilevsky, A; Belikov, S; Bellaiche, F G; Belyaev, S T; Bennett, M J; Berdnikov, Y; Botelho, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J; Butsyk, S; Carey, T A; Chand, P; Chang, J; Chang, W C; Chavez, L L; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choudhury, R K; Christ, T; Chujo, T; Chung, M S; Chung, P; Cianciolo, V; Cole, B A; D'Enterria, D G; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Dietzsch, O; Dinesh, B V; Drees, A; Durum, A; Dutta, D; Ebisu, K; Efremenko, Y V; El Chenawi, K; En'yo, H; Esumi, S; Ewell, L; Ferdousi, T; Fields, D E; Fokin, S L; Fraenkel, Z; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Godoi, A L; Goto, Y; Greene, S V; Grosse Perdekamp, M; Gupta, S K; Guryn, W; Gustafsson, H-A; Haggerty, J S; Hamagaki, H; Hansen, A G; Hara, H; Hartouni, E P; Hayano, R; Hayashi, N; He, X; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Ho, D S; Homma, K; Hong, B; Hoover, A; Ichihara, T; Imai, K; Ippolitov, M S; Ishihara, M; Jacak, B V; Jang, W Y; Jia, J; Johnson, B M; Johnson, S C; Joo, K S; Kametani, S; Kang, J H; Kann, M; Kapoor, S S; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D J; Kim, H J; Kim, S Y; Kim, Y G; Kinnison, W W; Kistenev, E; Kiyomichi, A; Klein-Boesing, C; Klinksiek, S; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kotchetkov, D; Kozlov, A; Kroon, P J; Kurita, K; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Lajoie, J G; Lauret, J; Lebedev, A; Lee, D M; Leitch, M J; Li, X H; Li, Z; Lim, D J; Liu, M X; Liu, X; Liu, Z; Maguire, C F; Mahon, J; Makdisi, Y I; Manko, V I; Mao, Y; Mark, S K; Markacs, S; Martinez, G; Marx, M D; Masaike, A; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Merschmeyer, M; Messer, F; Messer, M; Miake, Y; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagasaka, Y; Nagle, J L; Nakada, Y; Nandi, B K; Newby, J; Nikkinen, L; Nilsson, P; Nishimura, S; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Ono, M; Onuchin, V; Oskarsson, A; Osterman, L; Otterlund, I; Oyama, K; Paffrath, L; Palounek, A P T; Pantuev, V S; Papavassiliou, V; Pate, S F; Peitzmann, T; Petridis, A N; Pinkenburg, C; Pisani, R P; Pitukhin, P; Plasil, F; Pollack, M; Pope, K; Purschke, M L; Ravinovich, I; Read, K F; Reygers, K; Riabov, V; Riabov, Y; Rosati, M; Rose, A A; Ryu, S S; Saito, N; Sakaguchi, A; Sakaguchi, T; Sako, H; Sakuma, T; Samsonov, V; Sangster, T C; Santo, R; Sato, H D; Sato, S; Sawada, S; Schlei, B R; Schutz, Y; Semenov, V; Seto, R; Shea, T K; Shein, I; Shibata, T-A; Shigaki, K; Shiina, T; Shin, Y H; Sibiriak, I G; Silvermyr, D; Sim, K S; Simon-Gillo, J; Singh, C P; Singh, V; Sivertz, M; Soldatov, A; Soltz, R A; Sorensen, S; Stankus, P W; Starinsky, N; Steinberg, P; Stenlund, E; Ster, A; Stoll, S P; Sugioka, M; Sugitate, T; Sullivan, J P; Sumi, Y; Sun, Z; Suzuki, M; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Taniguchi, E; Tannenbaum, M J; Thomas, J; Thomas, J H; Thomas, T L; Tian, W; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tsvetkov, A A; Tuli, S K; Tydesjö, H; Tyurin, N; Ushiroda, T; van Hecke, H W; Velissaris, C; Velkovska, J; Velkovsky, M; Vinogradov, A A; Volkov, M A; Vorobyov, A; Vznuzdaev, E; Wang, H; Watanabe, Y; White, S N; Witzig, C; Wohn, F K; Woody, C L; Xie, W; Yagi, K; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, Z; Zhou, S

    2002-08-19

    Data from Au + Au interactions at sqrt[s(NN)]=130 GeV, obtained with the PHENIX detector at the Relativistic Heavy-Ion Collider, are used to investigate local net charge fluctuations among particles produced near midrapidity. According to recent suggestions, such fluctuations may carry information from the quark-gluon plasma. This analysis shows that the fluctuations are dominated by a stochastic distribution of particles, but are also sensitive to other effects, like global charge conservation and resonance decays. PMID:12190459

  20. Elliptic flow in Au+Au collisions at $\\sqrt{S_{NN}}$=130 GeV

    CERN Document Server

    Ackermann, K H; Adler, C; Ahammed, Z; Ahmad, S; Allgower, C; Amsbaugh, J; Anderson, M; Anderssen, E; Arnesen, H; Arnold, L; Averichev, G S; Baldwin, A R; Balewski, J T; Barannikova, O Yu; Barnby, L S; Baudot, J; Beddo, M E; Bekele, S; Belaga, V V; Bellwied, R; Bennett, S; Bercovitz, J; Berger, J; Betts, W; Bichsel, H; Bieser, F; Bland, L C; Bloomer, M A; Blyth, C O; Böhm, J; Bonner, B E; Bonnet, D; Bossingham, R R; Botlo, M; Boucham, A; Bouillo, N; Bouvier, S; Bradley, K; Brady, F P; Braithwaite, E S; Braithwaite, W; Brandin, A B; Brown, R L; Brugalette, G; Byrd, C; Caines, H; Calderón de la Barca-Sanchez, M; Cardenas, A; Carr, L; Carroll, J; Castillo, J; Caylor, B; Cebra, D; Chathopadhyay, S; Chen, M L; Chen, W; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Chrin, J; Christie, W; Coffin, J P; Conin, L; Consiglio, C; Cormier, T M; Cramer, J G; Crawford, H J; Danilov, V I; Dayton, D; De Mello, M; Deng, W S; Derevshchikov, A A; Dialinas, M; Díaz, H; De Young, P A; Didenko, L; Dimassimo, D; Dioguardi, J; Dominik, Wojciech; Drancourt, C; Draper, J E; Dunin, V B; Dunlop, J C; Eckardt, V; Edwards, W R; Efimov, L G; Eggert, T; Emelyanov, V I; Engelage, J; Eppley, G; Erazmus, B; Etkin, A; Fachini, P; Feliciano, C; Ferenc, D; Ferguson, M I; Fessler, H; Finch, E; Fine, V; Fisyak, Yu; Flierl, D; Flores, I; Foley, Kenneth J; Fritz, D; Gagunashvili, N D; Gans, J; Gazdzicki, M; Germain, M; Geurts, F J M; Ghazikhanian, V; Gojak, C; Grabski, J; Grachov, O A; Grau, M; Greiner, D E; Greiner, L; Grigoriev, V; Grosnick, D P; Gross, J; Guilloux, G; Gushin, E M; Hall, J; Hallman, T J; Hardtke, D; Harper, G; Harris, J W; He, P; Heffner, M; Heppelmann, S; Herston, T; Hill, D; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Howe, M; Huang, H Z; Humanic, T J; Hümmler, H; Hunt, W; Hunter, J; Igo, G; Ishihara, A; Ivanshin, Yu I; Jacobs, P; Jacobs, W W; Jacobson, S; Jared, R; Jensen, P; Johnson, I; Jones, P G; Judd, E; Kaneta, M; Kaplan, M; Keane, D; Kenney, V P; Khodinov, A; Klay, J L; Klein, S R; Klyachko, A A; Koehler, G; Konstantinov, A S; Kormilitsyne, V; Kotchenda, L; Kotov, I V; Kovalenko, A D; Krämer, M; Kravtsov, P; Krüger, K; Krupien, T; Kuczewski, P; Kühn, C E; Kunde, G J; Kunz, C L; Kutuev, R K; Kuznetsov, A A; Lakehal-Ayat, L; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lebedev, A; LeCompte, T J; Leonhardt, W; Leontiev, V M; Leszczynski, P; Le Vine, M J; Li, Q; Li, Z; Liaw, C J; Lin, J; Lindenbaum, S J; Lindenstruth, V; Lindstrom, P J; Lisa, M A; Liu, H; Ljubicic, T; Llope, W J; Lo Curto, G; Long, H; Longacre, R S; López-Noriega, M; Lopiano, D; Love, W A; Lutz, Jean Robert; Lynn, D; Madansky, L; Maier, R S; Majka, R; Maliszewski, A; Margetis, S; Marks, K; Marstaller, R; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; Matyushevsky, E A; McParland, C P; McShane, T S; Meier, J; Melnik, Yu M; Meshchanin, A P; Middlekamp, P; Mikhalin, N; Miller, B; Milosevich, Z; Minaev, N G; Minor, B; Mitchell, J; Mogavero, E; Moiseenko, V A; Moltz, D M; Moore, C F; Morozov, V; Morse, R; De Moura, M M; Munhoz, M G; Mutchler, G S; Nelson, J M; Nevski, P; Ngo, T; Nguyen, M; Nguyen, T; Nikitin, V A; Nogach, L V; Noggle, T; Norman, B; Nurushev, S B; Nussbaum, T; Nystrand, J; Odyniec, Grazyna Janina; Ogawa, A; Ogilvie, C A; Olchanski, K; Oldenburg, M; Olson, D; Ososkov, G A; Ott, G; Padrazo, D; Paic, G; Pandey, S U; Panebratsev, Yu A; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Pentia, M; Perevozchikov, V; Peryt, W; Petrov, V; Pinganaud, W; Pirogov, S; Platner, E D; Pluta, J; Polk, I; Porile, N T; Porter, J; Poskanzer, A M; Potrebenikova, E V; Prindle, D J; Pruneau, C A; Puskar-Pasewicz, J; Rai, G; Rasson, J E; Ravel, O; Ray, R L; Razin, S V; Reichhold, D M; Reid, J; Renfordt, R E; Retière, F; Ridiger, A; Riso, J; Ritter, H G; Roberts, J B; Röhrich, D; Rogachevski, O V; Romero, J L; Roy, C; Russ, D; Rykov, V L; Sakrejda, I; Sánchez, R; Sandler, Z; Sandweiss, J; Sappenfield, P; Saulys, A C; Savin, I A; Schambach, J; Scharenberg, R P; Scheblien, J; Scheetz, R; Schlüter, R; Schmitz, N; Schröder, L S; Schulz, M; Schüttauf, A; Sedlmeir, J; Seger, J E; Seliverstov, D M; Seyboth, J; Seyboth, P; Seymour, R; Shakaliev, E I; Shestermanov, K E; Shi, Y; Shimansky, S S; Shuman, D B; Shvetcov, V S; Skoro, G P; Smirnov, N; Smykov, L P; Snellings, R; Solberg, K; Sowinski, J; Spinka, H M; Srivastava, B; Stephenson, E J; Stock, Reinhard; Stolpovsky, A; Stone, N; Stone, R; Strikhanov, M N; Stringfellow, B C; Ströbele, H; Struck, C; Suaide, A A P; Sugarbaker, E R; Suire, C; Symons, T J M; Takahashi, J; Tang, A H; Tarchini, A; Tarzian, J; Thomas, J H; Tikhomirov, V; Szanto de Toledo, A; Tonse, S R; Trainor, T; Trentalange, S; Tokarev, M; Tonjes, M B; Trofimov, V N; Tsai, O; Turner, K; Ullrich, T S; Underwood, D G; Vakula, I; Van Buren, G

    2001-01-01

    Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at sqrt(s_NN)=130 GeV using the STAR TPC at RHIC. The elliptic flow signal, v_2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.

  1. Light Fragment Production and Power Law Behavior in Au + Au Collisions

    International Nuclear Information System (INIS)

    Using charged-particle-exclusive measurements of Au+Au collisions in the LBL Bevalac's EOS time projection chamber, we investigate momentum-space densities of fragments up to 4He as a function of fragment transverse momentum, azimuth relative to the reaction plane, rapidity, multiplicity, and beam energy. Most features of these densities above a transverse momentum threshold are consistent with momentum-space coalescence, and, in particular, the increase in sideward flow with fragment mass is generally well described by a momentum-space power law

  2. Relativistic multireference many-body perturbation theory calculations on Au64+ - Au69+ ions

    Energy Technology Data Exchange (ETDEWEB)

    Vilkas, M J; Ishikawa, Y; Trabert, E

    2006-03-31

    Many-body perturbation theory (MBPT) calculations are an adequate tool for the description of the structure of highly charged multi-electron ions and for the analysis of their spectra. They demonstrate this by way of a re-investigation of n=3, {Delta}n=0 transitions in the EUV spectra of Na-, Mg-, Al-like, and Si-like ions of Au that have been obtained previously by heavy-ion accelerator based beam-foil spectroscopy. They discuss the evidence and propose several revisions on the basis of the multi-reference many-body perturbation theory calculations of Ne- through P-like ions of Au.

  3. On direct photon production in Pb+Pb and Au+Au collisions

    CERN Document Server

    Guptaroy, P

    2003-01-01

    Some aspects of the direct photon production phenomenon are discussed, mainly in the Pb+Pb and Au+Au collisions on the basis of a model for production of the same particle species in PP collisions. The results have, thereafter, been converted to those for a few AB/AA interactions through an appropriate mechanism. Comparison of the theoretical results obtained on the basis of model-based calculations with measured data on the relevant observables leads to a fair agreement between them. This reflects modestly the fair achievements attained by the models that are made use of in the present work. (author)

  4. On direct photon production in Pb+Pb and Au+Au collisions

    International Nuclear Information System (INIS)

    Some aspects of the direct photon production phenomenon are discussed, mainly in the Pb+Pb and Au+Au collisions on the basis of a model for production of the same particle species in PP collisions. The results have, thereafter, been converted to those for a few AB/AA interactions through an appropriate mechanism. Comparison of the theoretical results obtained on the basis of model-based calculations with measured data on the relevant observables leads to a fair agreement between them. This reflects modestly the fair achievements attained by the models that are made use of in the present work. (author)

  5. Narrowing of the balance function with centrality in Au + Au collisions at √sNN

    International Nuclear Information System (INIS)

    The balance function is a new observable based on the principle that charge is locally conserved when particles are pair produced. Balance functions have been measured for charged particle pairs and identified charged pion pairs in Au + Au collisions at √sNN = 130 GeV at the Relativistic Heavy Ion Collider using STAR. Balance functions for peripheral collisions have widths consistent with model predictions based on a superposition of nucleon-nucleon scattering. Widths in central collisions are smaller, consistent with trends predicted by models incorporating late hadronization

  6. Spectator matter fragmentation in Au+Au reactions: Phase space analysis

    CERN Document Server

    Vermani, Yogesh K

    2011-01-01

    Clusterization in phase space has been analyzed for peripheral Au+Au reactions at 1000 AMeV using simulated annealing clusterization algorithm (SACA). We investigate how these fragments are correlated in phase space and compare our model calculations with minimum spanning tree (MST) method. Our theoretical study highlights the importance of binding energy criterion in recognizing the fragment structure. MST method however, fails to break-up the spectator matter effectively and thus under-estimates the multiplicity of intermediate mass fragments (IMFs).

  7. Beam-Energy Dependence of Charge Balance Functions from Au+Au Collisions at RHIC

    OpenAIRE

    STAR Collaboration

    2015-01-01

    Balance functions have been measured in terms of relative pseudorapidity ($\\Delta \\eta$) for charged particle pairs at the Relativistic Heavy-Ion Collider (RHIC) from Au+Au collisions at $\\sqrt{s_{\\rm NN}}$ = 7.7 GeV to 200 GeV using the STAR detector. These results are compared with balance functions measured at the Large Hadron Collider (LHC) from Pb+Pb collisions at $\\sqrt{s_{\\rm NN}}$ = 2.76 TeV by the ALICE Collaboration. The width of the balance function decreases as the collisions beco...

  8. Energy Dependence of Particle Multiplicities in Central Au+Au Collisions

    Science.gov (United States)

    Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Corbo, J.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Henderson, C.; Hicks, D.; Hofman, D.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A.; Mülmenstädt, J.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Rafelski, M.; Rbeiz, M.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2002-01-01

    We present the first measurement of the pseudorapidity density of primary charged particles in Au+Au collisions at (sNN) = 200 GeV. For the 6% most central collisions, we obtain dNch/dη\\|\\|η\\|<1 = 650+/-35(syst). Compared to collisions at (sNN) = 130 GeV, the highest energy studied previously, an increase by a factor of 1.14+/-0.05 at 90% confidence level, is found. The energy dependence of the pseudorapidity density is discussed in comparison with data from proton-induced collisions and theoretical predictions.

  9. Strangelet search in Au+Au collisions at VsNN=200 GeV

    OpenAIRE

    Bai, Y.(Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China); Benedosso, F.; Botje, M.A.J.; Grebenyuk, O.; Mischke, A.; Peitzmann, T.; Russcher, M.J.; Snellings, R.J.M.; van der Kolk, N.

    2007-01-01

    We have searched for strangelets in a triggered sample of 61 million central (top 4%) Au+Au collisions at √sNN=200 GeV near beam rapidities at the STAR solenoidal tracker detector at the BNL Relativistic Heavy Ion Collider. We have sensitivity to metastable strangelets with lifetimes of order ⩾0.1 ns, in contrast to limits over ten times longer in BNL Alternating Gradient Synchrotron (AGS) studies and longer still at the CERN Super Proton Synchrotron (SPS). Upper limits of a few 10-6 to 10-7 ...

  10. Azimuthal Anisotropy of Identified Hadrons in 200 GeV Au+Au Collisions

    CERN Document Server

    Oldenburg, M

    2006-01-01

    The azimuthal anisotropy parameter v2 has been measured with high statistics for identified hadrons in sqrt(s_NN) = 200 GeV Au+Au collisions with the STAR experiment. At high transverse momentum (pT) a strong v2 for pi+ + pi- and p + pbar is observed. In the intermediate pT region, number-of-constituent-quark scaling was tested to high precision. A detailed comparison of v2 for the multi-strange hadrons phi, Xi + anti-Xi, and Omega + anti-Omega with other particle species substantiates the development of collectivity among partons in the early phase of the collisions at RHIC.

  11. Azimuthal di-hadron correlations in d plus Au and Au plus Au collisions at root s(NN)=200 GeV measured at the STAR detector

    Czech Academy of Sciences Publication Activity Database

    Aggarwal, M. M.; Ahammed, Z.; Alakhverdyants, A. V.; Alekseev, I.; Alford, J.; Anderson, B.D.; Arkhipkin, D.; Averichev, G. S.; Balewski, J.; Barnby, L. S.; Baumgart, S.; Beavis, D.R.; Bellwied, R.; Betancourt, M.J.; Betts, R. R.; Bhasin, A.; Bhati, A.K.; Bichsel, H.; Bielčík, Jaroslav; Bielčíková, Jana; Biritz, B.; Bland, L.C.; Bonner, B.E.; Bouchet, J.; Braidot, E.; Brandin, A.V.; Bridgeman, A.; Bruna, E.; Bueltmann, S.; Bunzarov, I.; Burton, T. P.; Cai, X.Z.; Caines, H.; Sanchez, M.C.D.; Catu, O.; Cebra, D.; Cendejas, R.; Cervantes, M.C.; Chajecki, Z.; Chaloupka, Petr; Chattopadhyay, S.; Chen, H.F.; Chen, J.H.; Chen, J.Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, K.E.; Christie, W.; Chung, P.; Clarke, R.F.; Codrington, M.J.M.; Corliss, R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Leyva, A.D.; De Silva, L.C.; Debbe, R.R.; Dedovich, T. G.; Derevschikov, A.A.; de Souza, R.D.; Didenko, L.; Djawotho, P.; Dogra, S.M.; Dong, X.; Drachenberg, J.L.; Draper, J. E.; Dunlop, J.C.; Mazumdar, M.R.D.; Efimov, L.G.; Elhalhuli, E.; Elnimr, M.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Eun, L.; Evdokimov, O.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Fersch, R.G.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Gagliardi, C. A.; Gangaharan, D.R.; Ganti, M. S.; Garcia-Solis, E.J.; Geromitsos, A.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y.N.; Gordon, A.; Grebenyuk, O.; Grosnick, D.; Guertin, S.M.; Gupta, A.; Gupta, N.; Guryn, W.; Haag, B.; Hamed, A.; Han, L.X.; Harris, J.W.; Hays-Wehle, J.P.; Heinz, M.; Heppelmann, S.; Hirsch, A.; Hjort, E.; Hoffmann, A.M.; Hoffmann, G.W.; Hofman, D.J.; Horner, M.J.; Huang, B.; Huang, H.Z.; Humanic, T.J.; Huo, L.; Igo, G..; Jacobs, P.; Jacobs, W.W.; Jena, C.; Jin, F.; Jones, C.L.; Jones, P.G.; Joseph, J.; Judd, E.G.; Kabana, S.; Kajimoto, K.; Kang, K.; Kapitán, Jan; Kauder, K.; Keane, D.; Kechechyan, A.; Kettler, D.; Kikola, D.P.; Kiryluk, J.; Kisiel, A.; Klein, S.R.; Knospe, A.G.; Kocoloski, A.; Koetke, D.D.; Kollegger, T.; Konzer, J.; Koralt, I.; Koroleva, L.; Korsch, W.; Kotchenda, L.; Kushpil, Vasilij; Kravtsov, P.; Krueger, K.; Krus, M.; Kumar, L.; Kurnadi, P.; Lamont, M.A.C.; Landgraf, J.M.; LaPointe, S. (ed.); Lauret, J.; Lebedev, A.; Lednický, Richard; Lee, Ch.; Lee, J.H.; Leight, W.; LeVine, M.J.; Li, C.; Li, L.; Li, N.; Li, W.; Li, X.; Li, Y.; Li, Z.M.; Lin, G.; Lindenbaum, S.J.; Lisa, M.A.; Liu, F.; Liu, H.; Liu, J.; Ljubicic, T.; Llope, W.J.; Longacre, R.S.; Love, W.A.; Lu, Y.; Luo, X.; Ma, G.L.; Ma, Y.G.; Mahapatra, D. P.; Majka, R.; Mall, O.I.; Mangotra, L.K.; Manweiler, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H.S.; Matulenko, Yu.A.; McDonald, D.; McShane, T.S.; Meschanin, A.; Milner, R.; Minaev, N.G.; Mioduszewski, S.; Mischke, A.; Mitrovski, M.K.; Mohanty, B.; Mondal, M.M.; Morozov, B.; Morozov, D.A.; Munhoz, M. G.; Nandi, B.K.; Nattrass, C.; Nayak, T. K.; Nelson, J.M.; Netrakanti, P.K.; Ng, M.J.; Nogach, L.V.; Nurushev, S.B.; Odyniec, G.; Ogawa, A.; Okorokov, V.; Oldag, E.W.; Olson, D.; Pachr, M.; Page, B.S.; Pal, S.K.; Pandit, Y.; Panebratsev, Yu.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S.C.; Pile, P.; Planinic, M.; Ploskon, M.A.; Pluta, J.; Plyku, D.; Poljak, N.; Poskanzer, A.M.; Potukuchi, B.V.K.S.; Powell, C.B.; Prindle, D.; Pruneau, C.; Pruthi, N.K.; Pujahari, P.R.; Putschke, J.; Raniwala, R.; Raniwala, S.; Ray, R.L.; Redwine, R.; Reed, R.; Ritter, H.G.; Roberts, J.B.; Rogachevskiy, O.V.; Romero, J.L.; Rose, A.; Roy, C.; Ruan, L.; Sahoo, R.; Sakai, S.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sangaline, E.; Schambach, J.; Scharenberg, R.P.; Schmitz, N.; Schuster, T.R.; Seele, J.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shahaliev, E.; Shao, M.; Sharma, M.; Shi, S.S.; Sichtermann, E.P.; Simon, F.; Singaraju, R.N.; Skoby, M.J.; Smirnov, N.; Sorensen, P.; Sowinski, J.; Spinka, H.M.; Srivastava, B.; Stanislaus, T.D.S.; Staszak, D.; Stevens, J.R.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M.C.; Subba, N.L.; Šumbera, Michal; Sun, X.M.; Sun, Y.; Sun, Z.; Surrow, B.; Svirida, D.N.; Symons, T.J.M.; de Toledo, A. S.; Takahashi, J.; Tang, A.H.; Tang, Z.; Tarini, L.H.; Tarnowsky, T.; Thein, D.; Thomas, J.H.; Tian, J.; Timmins, A.R.; Timoshenko, S.; Tlustý, David; Tokarev, M. V.; Trainor, T.A.; Tram, V.N.; Trentalange, S.; Tribble, R. E.; Tsai, O.D.; Ulery, J.; Ullrich, T.; Underwood, D.G.; Van Buren, G.; van Leeuwen, M.; van Nieuwenhuizen, G.; Vanfossen, J.A.; Varma, R.; Vasconcelos, G.M.S.; Vasiliev, A. N.; Videbaek, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S.A.; Wada, M.; Walker, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J.S.; Wang, Q.; Wang, X.L.; Wang, Y.; Webb, G.; Westfall, G.D.; Whitten, C.; Wieman, H.; Wissink, S.W.; Witt, R.; Wu, Y.F.; Xie, W.; Xu, N.; Xu, Q.H.; Xu, W.; Xu, Y.; Xu, Z.; Xue, L.; Yang, Y.; Yepes, P.; Yip, K.; Yoo, I.K.; Yue, Q.; Zawisza, M.; Zbroszczyk, H.; Zhan, W.; Zhang, J.B.; Zhang, S.; Zhang, W.M.; Zhang, X.P.; Zhang, Y.; Zhang, Z.P.; Zhao, J.; Zhong, C.; Zhou, J.; Zhou, W.; Zhu, X.; Zhu, Y.H.; Zoulkarneev, R.; Zoulkarneeva, Y.

    2010-01-01

    Roč. 82, č. 2 (2010), 024912/1-024912/14. ISSN 0556-2813 Institutional research plan: CEZ:AV0Z10480505; CEZ:AV0Z10100502 Keywords : AU+AU COLLISIONS * RADIATION * PLASMA Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 3.416, year: 2010

  12. Balance functions from Au+Au, d+Au, and p+p collisions at root s(NN)=200 GeV

    Czech Academy of Sciences Publication Activity Database

    Aggarwal, M. M.; Ahammed, Z.; Alakhverdyants, A. V.; Alekseev, I.; Alford, J.; Anderson, B.D.; Arkhipkin, D.; Averichev, G. S.; Balewski, J.; Barnby, L. S.; Baumgart, S.; Beavis, D.R.; Bellwied, R.; Betancourt, M.J.; Betts, R. R.; Bhasin, A.; Bhati, A.K.; Bichsel, H.; Bielčík, Jaroslav; Bielčíková, Jana; Biritz, B.; Bland, L.C.; Bonner, B.E.; Bouchet, J.; Braidot, E.; Brandin, A.V.; Bridgeman, A.; Bruna, E.; Bueltmann, S.; Bunzarov, I.; Burton, T. P.; Cai, X.Z.; Caines, H.; Sanchez, M.C.D.; Catu, O.; Cebra, D.; Cendejas, R.; Cervantes, M.C.; Chajecki, Z.; Chaloupka, Petr; Chattopadhyay, S.; Chen, H.F.; Chen, J.H.; Chen, J.Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, K.E.; Christie, W.; Chung, P.; Clarke, R.F.; Codrington, M.J.M.; Corliss, R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Leyva, A.D.; De Silva, L.C.; Debbe, R.R.; Dedovich, T. G.; Derevschikov, A.A.; de Souza, R.D.; Didenko, L.; Djawotho, P.; Dogra, S.M.; Dong, X.; Drachenberg, J.L.; Draper, J. E.; Dunlop, J.C.; Mazumdar, M.R.D.; Efimov, L.G.; Elhalhuli, E.; Elnimr, M.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Eun, L.; Evdokimov, O.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Fersch, R.G.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Gagliardi, C. A.; Gangaharan, D.R.; Ganti, M. S.; Garcia-Solis, E.J.; Geromitsos, A.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y.N.; Gordon, A.; Grebenyuk, O.; Grosnick, D.; Guertin, S.M.; Gupta, A.; Gupta, N.; Guryn, W.; Haag, B.; Hamed, A.; Han, L.X.; Harris, J.W.; Hays-Wehle, J.P.; Heinz, M.; Heppelmann, S.; Hirsch, A.; Hjort, E.; Hoffmann, A.M.; Hoffmann, G.W.; Hofman, D.J.; Horner, M.J.; Huang, B.; Huang, H.Z.; Humanic, T.J.; Huo, L.; Igo, G..; Jacobs, P.; Jacobs, W.W.; Jena, C.; Jin, F.; Jones, C.L.; Jones, P.G.; Joseph, J.; Judd, E.G.; Kabana, S.; Kajimoto, K.; Kang, K.; Kapitán, Jan; Kauder, K.; Keane, D.; Kechechyan, A.; Kettler, D.; Kikola, D.P.; Kiryluk, J.; Kisiel, A.; Klein, S.R.; Knospe, A.G.; Kocoloski, A.; Koetke, D.D.; Kollegger, T.; Konzer, J.; Koralt, I.; Koroleva, L.; Korsch, W.; Kotchenda, L.; Kushpil, Vasilij; Kravtsov, P.; Krueger, K.; Krus, M.; Kumar, L.; Kurnadi, P.; Lamont, M.A.C.; Landgraf, J.M.; LaPointe, S. (ed.); Lauret, J.; Lebedev, A.; Lednický, Richard; Lee, Ch.; Lee, J.H.; Leight, W.; LeVine, M.J.; Li, C.; Li, L.; Li, N.; Li, W.; Li, X.; Li, Y.; Li, Z.M.; Lin, G.; Lindenbaum, S.J.; Lisa, M.A.; Liu, F.; Liu, H.; Liu, J.; Ljubicic, T.; Llope, W.J.; Longacre, R.S.; Love, W.A.; Lu, Y.; Luo, X.; Ma, G.L.; Ma, Y.G.; Mahapatra, D. P.; Majka, R.; Mall, O.I.; Mangotra, L.K.; Manweiler, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H.S.; Matulenko, Yu.A.; McDonald, D.; McShane, T.S.; Meschanin, A.; Milner, R.; Minaev, N.G.; Mioduszewski, S.; Mischke, A.; Mitrovski, M.K.; Mohanty, B.; Mondal, M.M.; Morozov, B.; Morozov, D.A.; Munhoz, M. G.; Nandi, B.K.; Nattrass, C.; Nayak, T. K.; Nelson, J.M.; Netrakanti, P.K.; Ng, M.J.; Nogach, L.V.; Nurushev, S.B.; Odyniec, G.; Ogawa, A.; Okorokov, V.; Oldag, E.W.; Olson, D.; Pachr, M.; Page, B.S.; Pal, S.K.; Pandit, Y.; Panebratsev, Yu.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S.C.; Pile, P.; Planinic, M.; Ploskon, M.A.; Pluta, J.; Plyku, D.; Poljak, N.; Poskanzer, A.M.; Potukuchi, B.V.K.S.; Powell, C.B.; Prindle, D.; Pruneau, C.; Pruthi, N.K.; Pujahari, P.R.; Putschke, J.; Raniwala, R.; Raniwala, S.; Ray, R.L.; Redwine, R.; Reed, R.; Ritter, H.G.; Roberts, J.B.; Rogachevskiy, O.V.; Romero, J.L.; Rose, A.; Roy, C.; Ruan, L.; Sahoo, R.; Sakai, S.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sangaline, E.; Schambach, J.; Scharenberg, R.P.; Schmitz, N.; Schuster, T.R.; Seele, J.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shahaliev, E.; Shao, M.; Sharma, M.; Shi, S.S.; Sichtermann, E.P.; Simon, F.; Singaraju, R.N.; Skoby, M.J.; Smirnov, N.; Sorensen, P.; Sowinski, J.; Spinka, H.M.; Srivastava, B.; Stanislaus, T.D.S.; Staszak, D.; Stevens, J.R.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M.C.; Subba, N.L.; Šumbera, Michal; Sun, X.M.; Sun, Y.; Sun, Z.; Surrow, B.; Svirida, D.N.; Symons, T.J.M.; de Toledo, A. S.; Takahashi, J.; Tang, A.H.; Tang, Z.; Tarini, L.H.; Tarnowsky, T.; Thein, D.; Thomas, J.H.; Tian, J.; Timmins, A.R.; Timoshenko, S.; Tlustý, David; Tokarev, M. V.; Trainor, T.A.; Tram, V.N.; Trentalange, S.; Tribble, R. E.; Tsai, O.D.; Ulery, J.; Ullrich, T.; Underwood, D.G.; Van Buren, G.; van Leeuwen, M.; van Nieuwenhuizen, G.; Vanfossen, J.A.; Varma, R.; Vasconcelos, G.M.S.; Vasiliev, A. N.; Videbaek, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S.A.; Wada, M.; Walker, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J.S.; Wang, Q.; Wang, X.L.; Wang, Y.; Webb, G.; Westfall, G.D.; Whitten, C.; Wieman, H.; Wissink, S.W.; Witt, R.; Wu, Y.F.; Xie, W.; Xu, N.; Xu, Q.H.; Xu, W.; Xu, Y.; Xu, Z.; Xue, L.; Yang, Y.; Yepes, P.; Yip, K.; Yoo, I.K.; Yue, Q.; Zawisza, M.; Zbroszczyk, H.; Zhan, W.; Zhang, J.B.; Zhang, S.; Zhang, W.M.; Zhang, X.P.; Zhang, Y.; Zhang, Z.P.; Zhao, J.; Zhong, C.; Zhou, J.; Zhou, W.; Zhu, X.; Zhu, Y.H.; Zoulkarneev, R.; Zoulkarneeva, Y.

    2010-01-01

    Roč. 82, č. 2 (2010), 024905/1-024905/16. ISSN 0556-2813 Institutional research plan: CEZ:AV0Z10480505; CEZ:AV0Z10100502 Keywords : HEAVY-ION COLLISIONS * AU-AU COLLISIONS * TIME PROJECTION CHAMBER Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 3.416, year: 2010

  13. Bridging gold in electron-deficient Al2Au(n)(0/-) and BAlAu(n)(0/-) (n = 1-3) clusters.

    Science.gov (United States)

    Yao, Wen-Zhi; Liu, Bing-Tao; Lu, Zhang-Hui; Li, Si-Dian

    2013-06-20

    The geometrical and electronic structures of the electron-deficient dialuminum aurides Al2Aun(0/-) and hybrid boron-aluminum aurides BAlAun(0/-) (n = 1-3) are systematically investigated based on the density and wave function theories. Ab initio theoretical evidence strongly suggests that bridging gold atoms exist in the ground states of C2v Al2Au(-) ((3)B1), C2v Al2Au ((2)B1), C2v Al2Au2(-) ((2)A1), C2v Al2Au2 ((1)A1), Cs Al2Au3(-) ((1)A'), and D3h Al2Au3 ((2)A1), which prove to possess an Al-Au-Al τ bond. For BAlAun(0/-) (n = 1-3) mixed clusters, bridging B-Au-Al units only exist in Cs BAlAu3(-) ((1)A') and Cs BAlAu3 ((2)A'), whereas Cs BAlAu(-) ((3)A''), Cs BAlAu ((2)A''), Cs BAlAu2(-) ((2)A'), and Cs BAlAu2 ((1)A') do not possess a bridging gold, as demonstrated by the fact that B-Al and B-Au exhibit significantly stronger electronic interaction than Al-Au in the same clusters. Orbital analyses indicate that Au 6s contributes approximately 98%-99% to the Au-based orbital in these Al-Au-Al/B-Au-Al interactions, whereas Au 5d contributes 1%-2%. The adiabatic and vertical detachment energies of Al2Aun(-) (n = 1-3) are calculated to facilitate future experimental characterizations. The results obtained in this work establish an interesting τ bonding model (Al-Au-Al/B-Au-Al) for electron-deficient systems in which Au 6s plays a major factor. PMID:23718624

  14. 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.

  15. Preferential Au precipitation at deformation-induced defects in Fe–Au and Fe–Au–B–N alloys

    International Nuclear Information System (INIS)

    Highlights: • Fe–Au–B–N forms a good model alloy system for self healing of deformation damage. • Solute Au atoms exclusively precipitate at grain boundaries, cracks and cavities. • XPS indicates a strong tendency for Au segregation on free surfaces at 550 °C. • Interstitial B and N form hexagonal BN on free surfaces at 550 °C. • Selective Au precipitation at open volume defects can cause autonomous repair. -- Abstract: The influence of deformation-induced defects on the isothermal precipitation of Au was studied in high-purity Fe–Au and Fe–Au–B–N alloys. Preferential Au precipitation upon annealing at 550 °C is observed at local plastic indentations. In fractured Fe–Au–B–N, solute Au atoms were found to heterogeneously precipitate at grain boundaries and local micro-cracks. This is supported by in-situ creep tests that showed a strong tendency for Au precipitation at cracks and cavities also formed during creep loading at 550 °C. Complementary X-ray photoelectron spectroscopy experiments indicate a strong tendency of Au, B and N segregation onto free surface during aging. The observed site-specific precipitation of Au holds interesting opportunities for defect healing in steels subjected to creep deformation

  16. Thermal stability of Mo/Au bilayers for TES applications

    International Nuclear Information System (INIS)

    Mo/Au bilayers are among the most suitable materials to be used as transition-edge sensors (TES) in cryogenic microcalorimeters and bolometers, developed, among other fields, for space missions. For this purpose the thermal stability of TES at temperatures below 150 °C is a critical issue. We report on the dependence of functional properties (superconducting critical temperature, residual resistance and α) as well as on microstructure, chemical composition and interface quality for optimized high quality Mo/Au bilayers on annealing temperature and time. Data show that the functional properties of the bilayers remain stable at T C at T ≥ 200 °C are mainly due to an increase in the average Au grain size and to Au migration along the Mo grain boundaries at the Au/Mo interface. A way to stabilize the functional properties of the Mo/Au bilayers against temperature enhancements is proposed. (paper)

  17. Les frameworks au coeur des applications web

    OpenAIRE

    Moro, Arielle; Daehne, Peter

    2010-01-01

    Depuis quelques années, Internet est vraiment entré dans les mœurs : tant dans les entreprises qu’au sein de chaque foyer. En effet, Internet permet de communiquer à travers le monde en quelques secondes, de vendre toute sorte de produits en déployant des solutions e-commerce facilement et bien d’autres choses. Internet est donc un véritable vecteur de communication, de commerce et à présent, avec le Web 2.0, un vrai berceau d’informations (tant des informations personnelles que des informati...

  18. Transition probability studies in 175Au

    International Nuclear Information System (INIS)

    Transition probabilities have been measured between the low-lying yrast states in 175Au by employing the recoil distance Doppler-shift method combined with the selective recoil-decay tagging technique. Reduced transition probabilities and magnitudes of transition quadrupole moments have been extracted from measured lifetimes allowing dramatic changes in nuclear structure within a low excitation-energy range to probed. The transition quadrupole moment data are discussed in terms of available systematics as a function of atomic number and aligned angular momentum.

  19. Le risque alimentaire face au consommateur

    OpenAIRE

    Didier Torny

    2005-01-01

    Dans le contexte contemporain de multiplication des crises sanitaires, de nombreux travaux en sciences économiques et sociales ont cherché à décrire et analyser le comportement des consommateurs face au risque alimentaire. Ces travaux partagent globalement deux prémisses : ils considèrent l'acte de consommation comme un comportement individuel et attribuent aux consommateurs des "perceptions du risque" qui orientent leurs choix. Une critique de ces deux axiomes amène à soulever la question de...

  20. Massignon face au sionisme Massignon and Zionism

    OpenAIRE

    Agathe Mayeres

    2010-01-01

    En 1916, Louis Massignon participe aux négociations franco-britanniques qui envisagent, dans la perspective de la capitulation probable des empires centraux, le futur partage de l’Empire ottoman. Dans ce contexte, Massignon cherche à se situer face la question sioniste qui, pour lui, est avant tout un problème de politique orientale.Sous l’influence d'Aaron Aaronsohn, l’islamologue éprouve d’abord pour les pionniers d’Eretz Israel, au regard de leurs réalisations agricoles, une sympathie enth...

  1. Les produits de terroir au Niger

    OpenAIRE

    Luxereau, Anne

    2013-01-01

    Les productions agricoles localisées, bénéficiant de ce fait d’une notoriété particulière, existent depuis longtemps en Afrique. Au Niger, elles sont nombreuses et leur statut est diversifié, entre des produits « patrimoines » et d’autres qui constituent des opportunités économiques récentes. Longtemps ignorés des projets de développement, ils connaissent actuellement des évolutions disparates mais la plupart du temps endogènes, « informelles » et innovantes. Tous commercialisés, ils particip...

  2. Que faisons-nous au CERN ?

    CERN Multimedia

    1999-01-01

    Le CERN a pour vocation la science pure, l'étude des questions les plus fondamentales de la nature:Qu'est-ce que la matière ?D'ou vient-elle ? Comment s'agglomère-t-elle en formes complexes comme les étoiles, les planètes et les êtres humains ? Au CERN, les collisions de particules servent à sonder le coeur de la matière et les chercheurs du Laboratoire étudient ces millions de collisions de particules afin de trouver des réponses à ces questions.

  3. L'adaptation au changement climatique

    OpenAIRE

    Institut National de Recherche Agronomique UAR 0233 Collège de Direction

    2007-01-01

    Il est maintenant admis que l’adaptation demeure tout aussi importante que l’atténuation pour gérer le risque climatique. Mais qu'est-ce que l’adaptation au changement climatique? À travers cet ouvrage de synthèse, Van Gameren V., R. Weikmans et E. Zaccai, chercheurs issus du Centre d’études et du développement durable (CEDD) de l’Université libre de Bruxelles (ULB), y répondent en abordant les enjeux de l’adaptation dans le domaine du changement climatique ainsi que les futures avenues possi...

  4. Compressive mechanical behavior of Au nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Wen Yuhua, E-mail: yhwen@xmu.edu.c [Department of Physics, and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen 361005 (China); Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg, Manitoba, R3T 5V6 (Canada); Wang Quan, E-mail: q_wang@umanitoba.c [Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg, Manitoba, R3T 5V6 (Canada); Liew, Kim Meow [Department of Building and Construction, City University of Hong Kong (Hong Kong); Zhu Zizhong [Department of Physics, and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen 361005 (China)

    2010-06-28

    The structural evolution, deformation mechanism, and failure behavior of Au [001] nanowires with various sizes and slenderness ratios under uniaxial compression have been investigated using molecular dynamics. The results show that the elastic modulus, yield stress, and strain all are dependent on the diameters and slenderness ratios of the nanowires. Buckling behavior is observed in a long nanowire, followed by slips in the {l_brace}111{r_brace} planes. Differences are identified in the failure behavior of a short nanowire and a medium nanowire, although the plastic deformation of both types of nanowire originates from the slips in the {l_brace}111{r_brace} planes.

  5. Compressive mechanical behavior of Au nanowires

    International Nuclear Information System (INIS)

    The structural evolution, deformation mechanism, and failure behavior of Au [001] nanowires with various sizes and slenderness ratios under uniaxial compression have been investigated using molecular dynamics. The results show that the elastic modulus, yield stress, and strain all are dependent on the diameters and slenderness ratios of the nanowires. Buckling behavior is observed in a long nanowire, followed by slips in the {111} planes. Differences are identified in the failure behavior of a short nanowire and a medium nanowire, although the plastic deformation of both types of nanowire originates from the slips in the {111} planes.

  6. Phase behavior of Au and Pt surfaces

    DEFF Research Database (Denmark)

    Grübel, G.; Gibbs, D.; Zehner, D.M.;

    1993-01-01

    We summarize the results of X-ray scattering studies of the Au(001) and Pt(001) surfaces between 300 K and their respective bulk melting temperatures (T(m)). Both surfaces exhibit three distinct structural phases. At high temperatures (0.88T(m) < T < T(m)) both surfaces are disordered. The Pt(001......) surface is rough. At a temperature of T/T(m) almost-equal-to 0.88 there are reversible phase transformations to incommensurate, corrugated-hexagonal phases. Below T/T(m) almost-equal-to 0.8 hexagonal domains rotate with respect to the substrate orientation. In Pt, the rotational transformation is...

  7. Photosynthetic electron transport system promotes synthesis of Au-nanoparticles.

    Science.gov (United States)

    Shabnam, Nisha; Pardha-Saradhi, P

    2013-01-01

    In this communication, a novel, green, efficient and economically viable light mediated protocol for generation of Au-nanoparticles using most vital organelle, chloroplasts, of the plant system is portrayed. Thylakoids/chloroplasts isolated from Potamogeton nodosus (an aquatic plant) and Spinacia oleracea (a terrestrial plant) turned Au³⁺ solutions purple in presence of light of 600 µmol m⁻² s⁻¹ photon flux density (PFD) and the purple coloration intensified with time. UV-Vis spectra of these purple colored solutions showed absorption peak at ∼545 nm which is known to arise due to surface plasmon oscillations specific to Au-nanoparticles. However, thylakoids/chloroplasts did not alter color of Au³⁺ solutions in dark. These results clearly demonstrated that photosynthetic electron transport can reduce Au³⁺ to Au⁰ which nucleate to form Au-nanoparticles in presence of light. Transmission electron microscopic studies revealed that Au-nanoparticles generated by light driven photosynthetic electron transport system of thylakoids/chloroplasts were in range of 5-20 nm. Selected area electron diffraction and powder X-ray diffraction indicated crystalline nature of these nanoparticles. Energy dispersive X-ray confirmed that these nanoparticles were composed of Au. To confirm the potential of light driven photosynthetic electron transport in generation of Au-nanoparticles, thylakoids/chloroplasts were tested for their efficacy to generate Au-nanoparticles in presence of light of PFD ranging from 60 to 600 µmol m⁻² s⁻¹. The capacity of thylakoids/chloroplasts to generate Au-nanoparticles increased remarkably with increase in PFD, which further clearly demonstrated potential of light driven photosynthetic electron transport in reduction of Au³⁺ to Au⁰ to form nanoparticles. The light driven donation of electrons to metal ions by thylakoids/chloroplasts can be exploited for large scale production of nanoparticles. PMID:23976990

  8. Photosynthetic electron transport system promotes synthesis of Au-nanoparticles.

    Directory of Open Access Journals (Sweden)

    Nisha Shabnam

    Full Text Available In this communication, a novel, green, efficient and economically viable light mediated protocol for generation of Au-nanoparticles using most vital organelle, chloroplasts, of the plant system is portrayed. Thylakoids/chloroplasts isolated from Potamogeton nodosus (an aquatic plant and Spinacia oleracea (a terrestrial plant turned Au³⁺ solutions purple in presence of light of 600 µmol m⁻² s⁻¹ photon flux density (PFD and the purple coloration intensified with time. UV-Vis spectra of these purple colored solutions showed absorption peak at ∼545 nm which is known to arise due to surface plasmon oscillations specific to Au-nanoparticles. However, thylakoids/chloroplasts did not alter color of Au³⁺ solutions in dark. These results clearly demonstrated that photosynthetic electron transport can reduce Au³⁺ to Au⁰ which nucleate to form Au-nanoparticles in presence of light. Transmission electron microscopic studies revealed that Au-nanoparticles generated by light driven photosynthetic electron transport system of thylakoids/chloroplasts were in range of 5-20 nm. Selected area electron diffraction and powder X-ray diffraction indicated crystalline nature of these nanoparticles. Energy dispersive X-ray confirmed that these nanoparticles were composed of Au. To confirm the potential of light driven photosynthetic electron transport in generation of Au-nanoparticles, thylakoids/chloroplasts were tested for their efficacy to generate Au-nanoparticles in presence of light of PFD ranging from 60 to 600 µmol m⁻² s⁻¹. The capacity of thylakoids/chloroplasts to generate Au-nanoparticles increased remarkably with increase in PFD, which further clearly demonstrated potential of light driven photosynthetic electron transport in reduction of Au³⁺ to Au⁰ to form nanoparticles. The light driven donation of electrons to metal ions by thylakoids/chloroplasts can be exploited for large scale production of nanoparticles.

  9. Energy level alignment in Au/pentacene/PTCDA trilayer stacks

    OpenAIRE

    Sehati, Parisa; Braun, Slawomir; Fahlman, Mats

    2013-01-01

    Ultraviolet photoelectron spectroscopy is used to investigate the energy level alignment and molecular orientation at the interfaces in Au/pentacene/PTCDA trilayer stacks. We deduced a standing orientation for pentacene grown on Au while we conclude a flat lying geometry for PTCDA grown onto pentacene. We propose that the rough surface of polycrystalline Au induces the standing geometry in pentacene. It is further shown that in situ deposition of PTCDA on pentacene can influence the orientati...

  10. Enhanced Photoresponse of Conductive Polymer Nanowires Embedded with Au Nanoparticles.

    Science.gov (United States)

    Zhang, Junchang; Zhong, Liubiao; Sun, Yinghui; Li, Anran; Huang, Jing; Meng, Fanben; Chandran, Bevita K; Li, Shuzhou; Jiang, Lin; Chen, Xiaodong

    2016-04-01

    A conductive polymer nanowire embedded with a 1D Au nanoparticle chain with defined size, shape, and interparticle distance is fabricated which demonstrates enhanced photoresponse behavior. The precise and controllable positioning of 1D Au nanoparticle chain in the conductive polymer nanowire plays a critical role in modulating the photoresponse behavior by excitation light wavelength or power due to the coupled-plasmon effect of 1D Au nanoparticle chain. PMID:26901850

  11. RHIC performance for FY2011 Au+Au heavy ion run

    International Nuclear Information System (INIS)

    Following the Fiscal Year (FY) 2010 (Run-10) Relativistic Heavy Ion Collider (RHIC) Au+Au run, RHIC experiment upgrades sought to improve detector capabilities. In turn, accelerator improvements were made to improve the luminosity available to the experiments for this run (Run-11). These improvements included: a redesign of the stochastic cooling systems for improved reliability; a relocation of 'common' RF cavities to alleviate intensity limits due to beam loading; and an improved usage of feedback systems to control orbit, tune and coupling during energy ramps as well as while colliding at top energy. We present an overview of changes to the Collider and review the performance of the collider with respect to instantaneous and integrated luminosity goals. At the conclusion of the FY 2011 polarized proton run, preparations for heavy ion run proceeded on April 18, with Au+Au collisions continuing through June 28. Our standard operations at 100 GeV/nucleon beam energy was bracketed by two shorter periods of collisions at lower energies (9.8 and 13.5 GeV/nucleon), continuing a previously established program of low and medium energy runs. Table 1 summarizes our history of heavy ion operations at RHIC.

  12. Kaon production in Au+Au collisions at 11.6A GeV/c

    International Nuclear Information System (INIS)

    A systematic study of the spectra and yields of K+ and K- is reported by experiment E866 as a function of centrality in Au+Au collisions at 11.6A GeV/c. The invariant transverse spectra for both kaon species are well described by exponentials in mt, with inverse slope parameters that are largest at midrapidity and which increase with centrality. The inverse slopes of the K+ spectra are slightly larger than the inverse slopes of the K- spectra. The kaon rapidity density peaks at midrapidity with the K+ distribution wider in rapidity than K-. The integrated total yields of K+ and K- increase nonlinearly and steadily with the number of projectile participants. The yield per participant for kaons is two to three times larger than the yield from N-N collisions. This enhancement suggests that the majority of kaons in central Au+Au reactions are produced in secondary hadronic collisions. There is no evidence for an onset of additional kaon production from a possible small volume of baryon-rich quark-gluon plasma. The differences between K+ and K- rapidity distributions and transverse spectra are consistent with a lower phase space for K- production due to a higher energy threshold. These differences also exclude simple thermal models that assume emission from a common equilibrated system. copyright 1998 The American Physical Society

  13. Atomistic simulations of Au-silica nanocomposite film growth

    Science.gov (United States)

    Khan, Saif A.; Heinig, K.-H.; Avasthi, D. K.

    2011-05-01

    The growth of Au-silica nanocomposite film is simulated in the framework of kinetic three dimensional lattice Monte Carlo simulations considering the basic phenomena in the deposition process. In case of co-sputter deposition, the growth kinetics of nanoparticles has been studied taking into consideration the effect of the energetic sputtered species reaching the surface of the film during deposition. Formation of Au nanorod like structures are predicted under certain growth conditions particularly when surface diffusion assisted phase separation plays the dominant role and bulk kinetics is frozen. The observed dependence of the Au nanoparticle size on Au/silica ratio is in agreement with the experimental results.

  14. The self assembly of thymine at Au(110)/liquid interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Molina Contreras, J.R. [Departamento de Ingenieria Electrica y Electronica, Instituto Tecnologico de Aguascalientes, Mexico (Mexico); Smith, C.I.; Bowfield, A.; Weightman, P. [Physics Department, University of Liverpool (United Kingdom); Tillner, F. [Fachbereich Physik, Universitaet Konstanz (Germany)

    2012-06-15

    We show that thymine self-assembles into an ordered structure when adsorbed at a Au(110)/liquid interface. Reflection anisotropy spectroscopy (RAS) shows that as found for cytosine and adenine the adsorbed thymine molecules are oriented essentially vertically on the Au(110) surface with the molecule aligned along one of the principal axes of the Au(110) surface. Simulations of the RA spectra to an empirical model indicates that as found for adsorbed cytosine and adenine, thymine is aligned along the [1 anti 10] direction on the Au(110) surface. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Nanostructuring thin Au films on transparent conductive oxide substrates

    International Nuclear Information System (INIS)

    Highlights: ► Thermal-induced morphology evolution of Au nanoclusters on ITO is studied. ► Laser irradiation-induced morphology evolution of thin Au film on ITO is studied. ► Au nanorings formation on ITO is presented. ► Au nanoclusters formation on ITO is presented. -- Abstract: Fabrication processes of Au nanostructures on indium-tin-oxide (ITO) surface by simple, versatile, and low-cost bottom-up methodologies are investigated in this work. A first methodology exploits the patterning effects induced by nanosecond laser irradiations on thin Au films deposited on ITO surface. We show that after the laser irradiations, the Au film break-up into nanoclusters whose mean size and surface density are tunable by the laser fluence. A second methodology exploits, instead, the patterning effects of standard furnace thermal processes on the Au film deposited on the ITO. We observe, in this case, a peculiar shape evolution from pre-formed nanoclusters during the Au deposition stage on the ITO, to holed nanostructures (i.e. nanorings), during the furnace annealing processes. The nanorings depth, height, width, and surface density are shown to be tunable by annealing temperature and time

  16. Tailoring the FeRh magnetostructural response with Au diffusion

    OpenAIRE

    Loving, Melissa. L.; De Vries, Mark; Gimenez-Villacorta, Felix; Liu, Xuerong; Langridge, Sean; Heiman, Donald; Marrows, Christopher M.; Lewis, Laura

    2012-01-01

    Factors which contribute to magnetostructural transition control have been demonstrated by study of the effects of Au incorporation on the magnetic and structural character of CsCl-structured equiatomic FeRh thin films. Sputtered films were capped with 2 nm of Au deposited at 873 K and at 323 K and subsequently characterized with magnetometry and synchrotron-based structural probes. Diffusion of Au into the FeRh film layer at 873 K is confirmed by a reduction in the Au capping layer thickness...

  17. Structural and optical studies of Au doped titanium oxide films

    International Nuclear Information System (INIS)

    Thin films of TiO2 were doped with Au by ion implantation and in situ during the deposition. The films were grown by reactive magnetron sputtering and deposited in silicon and glass substrates at a temperature around 150 °C. The undoped films were implanted with Au fluences in the range of 5 × 1015 Au/cm2–1 × 1017 Au/cm2 with a energy of 150 keV. At a fluence of 5 × 1016 Au/cm2 the formation of Au nanoclusters in the films is observed during the implantation at room temperature. The clustering process starts to occur during the implantation where XRD estimates the presence of 3–5 nm precipitates. After annealing in a reducing atmosphere, the small precipitates coalesce into larger ones following an Ostwald ripening mechanism. In situ XRD studies reveal that Au atoms start to coalesce at 350 °C, reaching the precipitates dimensions larger than 40 nm at 600 °C. Annealing above 700 °C promotes drastic changes in the Au profile of in situ doped films with the formation of two Au rich regions at the interface and surface respectively. The optical properties reveal the presence of a broad band centered at 550 nm related to the plasmon resonance of gold particles visible in AFM maps.

  18. Magnetic holes in the solar wind between 0.3 AU and 17 AU

    Directory of Open Access Journals (Sweden)

    K. Sperveslage

    2000-01-01

    Full Text Available Magnetic holes (MHs are depressions of the magnetic field magnitude. Turner et al. (1977 identified the first MHs in the solar wind and determined an occurrence rate of 1.5 MHs/d. Winterhalter et al. (1994 developed an automatic identification criterion to search for MHs in Ulysses data in the solar wind between 1 AU and 5.4 AU. We adopt their criterion to expand the search to the heliocentric distances down to 0.3 AU using data from Helios 1 and 2 and up to 17 AU using data from Voyager 2. We relate our observations to two theoretical approaches which describe the so-called linear MHs in which the magnetic vector varies in magnitude rather than direction. Therefore we focus on such linear MHs with a directional change less than 10º. With our observations of about 850 MHs we present the following results: Approximately 30% of all the identified MHs are linear. The maximum angle between the initial magnetic field vector and any vector inside the MH is 20º in average and shows a weak relation to the depth of the MHs. The angle between the initial magnetic field and the minimum variance direction of those structures is large and very probably close to 90º. The MHs are placed in a high β environment even though the average solar wind shows a smaller β. The widths decrease from about 50 proton inertial length in a region between 0.3 AU and 0.4 AU heliocentric distance to about 15 proton inertial length at distances larger than 10 AU. This quantity is correlated with the β of the MH environments with respect to the heliocentric distance. There is a clear preference for the occurrence of depressions instead of compressions. We discuss these results with regard to the main theories of MHs, the mirror instability and the alternative soliton approach. Although our observational results are more consistent with the soliton theory we favour a combination of both. MHs might be the remnants of initial mirror mode structures which can be described as

  19. Enhanced production of direct photons in Au+Au collisions at sqrt(s_NN)=200 GeV

    CERN Document Server

    Adare, A; 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; Bucher, D; Büsching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Campbell, S; Chai, J S; Chang, B S; Charvet, J L; Chernichenko, S; Chiba, J; Chi, C Y; Chiu, M; Choi, I J; 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; Dahms, T; Das, K; David, o G; Deaton, M B; Dehmelt, K; Delagrange, H; Denisov, A; d'Enterria, D; Deshpande, A; Desmond, E J; Dietzsch, O; Dion, A; Donadelli, M; Drachenberg, J L; Drapier, O; Drees, A; Dubey, A K; Durum, A; 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; Finger, M; Finger, M; Fleuret, F; Fokin, S L; Forestier, B; 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, AT; Hadj Henni, A; Haegemann, C; Haggerty, J S; Hagiwara, M N; Hamagaki, H; Han, R; 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; Hiejima, H; Hill, J C; Hobbs, R; Hohlmann, M; Holmes, M; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hornback, D; Hur, M G; Ichihara, T; Imai, K; Inaba, M; Inoue, Y; Isenhower, D; Isenhower, L; Ishihara, M; Isobe, T; Issah, M; Isupov, A; Jacak, B V; Jia, J; Jin, J; Jinnouchi, O; Johnson, B M; Joo, K S; Jouan, D; Kajihara, F; Kametani, S; Kamihara, N; Kamin, J; Kaneta, M; Kang, J H; Kanou, H; Kawagishi, T; Kawall, D; Kazantsev, A V; Kelly, S; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, E; Kim, Y S; Kinney, E; Kiss, A; Kistenev, E; Kiyomichi, A; Klay, J; Klein-Bösing, C; Kochenda, L; Kochetkov, V; Komkov, B; Konno, M; Kotchetkov, D; Kozlov, A; Krl, A; Kravitz, A; Kroon, P J; Kubart, J; 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, A; Liu, M X; Li, X; Li, X H; Love, s B; Lynch, D; Maguire, C F; Makdisi, Y I; Malakhov, A; Malik, M D; Man'ko, V I; Mao, Y; Maek, L; Masui, H; Matathias, F; McCain, M C; McCumber, M; McGaughey, P L; Miake, Y; Mike, s P; Miki, K; Miller, T E; Milov, A; Mioduszewski, S; Mishra, G C; Mishra, M; Mitchell, J T; Mitrovski, s M; Morreale, A; Morrison, D P; Moss, J M; Moukhanova, T V; Mukhopadhyay, D; 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; Ozawa, K; Pak, R; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, J; Park, W J; Pate, S F; Pei, H; Peng, J C; Pereira, H; Peresedov, V; Peressounko, D Yu; Pinkenburg, C; Pisani, R P; Purschke, M L; Purwar, A K; 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; Sato, H D; Sato, S; Sawada, S; 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, 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; Vale, C; Valle, H; van Hecke, H W; Velkovska, o J; Vertesi, R; Vinogradov, A A; Virius, M; Vrba, V; Vznuzdaev, E; Wagner, M; Walker, D; Wang, X R; Watanabe, Y; Wessels, J; White, S N; Willis, N; Winter, D; 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

    2008-01-01

    The production of low mass e+e- pairs for m_{e+e-} < 300 MeV/c^2 and 1 < p_T <5 GeV/c is measured in p+p and Au+Au collisions at sqrt(s_NN)=200 GeV. Enhanced e+e- pair yield above hadronic sources is observed in Au+Au collisions. Treating the excess as internal conversion of direct photons, the invariant yield of direct photons is deduced. In central Au+Au collisions, the excess over p+p is exponential in p_T}, with inverse slope T = 221 +/- 23 (stat) +/- 18 (syst) MeV. Hydrodynamical models with initial temperatures T_init ~ 300-600 MeV at times of 0.6 - 0.15 fm/c after the collision are in qualitative agreement with the data. Lattice QCD predicts a phase transition at ~ 170 MeV.

  20. Au cœur du Tian Chan : histoire et devenir de la transhumance au Kirghizstan

    OpenAIRE

    Jacquesson, Svetlana

    2009-01-01

    Commençons par un fait évident : le Kirghizstan est un pays de montagnes. Plus de 94 % de son territoire est situé au dessus de 1 000 m et environ 71 % plus haut que 2 000 m. Le lac Ïssïk-köl (1 607 m d’altitude) entouré au nord par le Küngöy Ala-too (4 771 m au sommet Čok-tal) et au sud par le Teskey Ala-too (5 216 m au sommet Karakol) est ce que les Kirghiz appellent « le cœur » de leur pays. Au sud du Teskey Ala-too, les chaînes montagneuses du Tian Chan s’ouvrent sur quelques vallées de s...

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

    KAUST Repository

    Song, HyonMin

    2012-09-27

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

  2. Component conversion from pure Au nanorods to multiblock Ag-Au-Ag nanorods assisted by Pt nanoframe templates

    Science.gov (United States)

    Lee, Sangji; Jang, Hee-Jeong; Jang, Ho Young; Kim, Seong Kyu; Park, Sungho

    2016-06-01

    We developed a new method for synthesizing multiblock Ag-Au-Ag nanorods using Pt nanoframes that had been deposited on the edges of Au nanorod seeds. As a function of Au etching time, the length of the Au nanorod decreased symmetrically starting from the two ends, leading to the formation of empty inner space at the ends. Subsequent reduction of Ag ions could be selectively performed in the inner space confined by Pt nanoframes and the resulting Ag-Au-Ag nanorods exhibited characteristic LSPR modes originating from each block component (in a transverse direction) and SPR coupling (in a longitudinal direction). The high quality of the resulting multiblock nanorods enabled observation of the longitudinal quadrupole mode that was induced by Ag-Au SPR coupling in a long axis. The mode exhibited high sensitivity in accordance with the change in the surrounding media, demonstrating great potential for sensor applications.We developed a new method for synthesizing multiblock Ag-Au-Ag nanorods using Pt nanoframes that had been deposited on the edges of Au nanorod seeds. As a function of Au etching time, the length of the Au nanorod decreased symmetrically starting from the two ends, leading to the formation of empty inner space at the ends. Subsequent reduction of Ag ions could be selectively performed in the inner space confined by Pt nanoframes and the resulting Ag-Au-Ag nanorods exhibited characteristic LSPR modes originating from each block component (in a transverse direction) and SPR coupling (in a longitudinal direction). The high quality of the resulting multiblock nanorods enabled observation of the longitudinal quadrupole mode that was induced by Ag-Au SPR coupling in a long axis. The mode exhibited high sensitivity in accordance with the change in the surrounding media, demonstrating great potential for sensor applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr03484e

  3. Mesomorphic Lamella Rolling of Au in Vacuum

    Directory of Open Access Journals (Sweden)

    Chen Shuei-Yuan

    2009-01-01

    Full Text Available Abstract Lamellar nanocondensates in partial epitaxy with larger-sized multiply twinned particles (MTPs or alternatively in the form of multiple-walled tubes (MWTs having nothing to do with MTP were produced by the very energetic pulse laser ablation of Au target in vacuum under specified power density and pulses. Transmission electron microscopic observations revealed (111-motif diffraction and low-angle scattering. They correspond to layer interspacing (0.241–0.192 nm and the nearest neighbor distance (ca. 0.74–0.55 nm of atom clusters within the layer, respectively, for the lamella, which shows interspacing contraction with decreasing particle size under the influence of surface stress and rolls up upon electron irradiation. The uncapped MWT has nearly concentric amorphous layers interspaced by 0.458–0.335 nm depending on dislocation distribution and becomes spherical onions for surface-area reduction upon electron dosage. Analogous to graphene-derived tubular materials, the lamella-derived MWT of Au could have pentagon–hexagon pair at its zig-zag junction and useful optoelectronic properties worthy of exploration.

  4. Le fonds Gabriel Tarde au CHEVS

    Directory of Open Access Journals (Sweden)

    Louise Salmon

    2005-09-01

    Full Text Available Le fonds d’archives « Gabriel Tarde » déposé au CHEVS nous permet de mieux saisir l’érudit autodidacte que fut Gabriel Tarde. De la genèse de sa pensée à ses réseaux de sociabilité, de l’homme de sciences à l’homme de lettres, ses archives témoignent à la fois des usages et des enjeux des ressources archivistiques en histoire, mais elles permettent surtout un renouvellement du regard sur Gabriel Tarde en l’inscrivant au cœur de son temps que fut la fin du XIXème siècle.At the CHEVS in Paris, Gabriel Tarde’s archives allow us to grasp the self-taught scholar who was Gabriel Tarde. From the genesis of his intellect thought to his circles of sociability, from the scientist to the man of letters, his archives testify to the uses and the stakes of the archivistic resources in history, but they allow especially a renewal of the glance on Gabriel Tarde by inscribing him in his historical time, the end of the XIXth century.

  5. Facet selective etching of Au microcrystallites

    Institute of Scientific and Technical Information of China (English)

    Gangaiah Mettela and Giridhar U. Kulkarni

    2015-01-01

    High-symmetry crystals exhibit isotropic properties. Inducing anisotropy, e.g., by facet selective etching, is considered implausible in face-centered cubic (FCC) metals, particularly gold, which, in addition to being an FCC, is noble. We report for the first time the facet selective etching of Au microcrystals obtained in the form of cuboctahedra and pentagonal rods from the thermolysis of a gold- organic precursor. The selective etching of {111} and {100} facets was achieved using a capping method in which tetraoctylammonium cations selectively cap the {111} facets while Br- ions protect the {100} facets. The exposed facets are oxidized by O2/C1-, yielding a variety of interesting geometries. The facet selective etching of the Au microcrystallites is governed only by the nature of the facets; the geometry of the microcystallite does not appear to play a significant role. The etched surfaces appear rough, but a closer examination reveals well-defined corrugations that are indexable to high hkl values. Such surfaces exhibit enhanced Raman activity.

  6. Apprentissage administratif : L'apprentissage au CERN

    CERN Multimedia

    2004-01-01

    APPRENTISSAGE ADMINISTRATIF FORMATION ET DEVELOPPEMENT HR/PMD/RCC L'APPRENTISSAGE AU CERN pour les professions d'employé(e) de commerce et d'assistant(e) en information documentaire 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). 1 place est offerte pour la formation d'employé(e) de commerce 2 places sont offertes pour la formation d'assistant(e) en information documentaire L'apprentissage dure 3 ans. Minima requis pour faire acte de candidature : • avoir terminé la scolarité obligatoire • être ressortissant d'un pays membre du CERN (Allemagne, Autriche, Belgique, Bulgarie, Danemark, Espagne,Finlande, France, Grèce, Hongrie, Italie, Norvège...

  7. Imaging Prominence Eruptions Out to 1 AU

    CERN Document Server

    Wood, Brian E; Linton, Mark G

    2015-01-01

    Views of two bright prominence eruptions trackable all the way to 1AU are here presented, using the heliospheric imagers on the Solar TErrestrial RElations Observatory (STEREO) spacecraft. The two events first erupted from the Sun on 2011 June 7 and 2012 August 31, respectively. Only these two examples of clear prominence eruptions observable this far from the Sun could be found in the STEREO image database, emphasizing the rarity of prominence eruptions this persistently bright. For the 2011 June event, a time-dependent 3-D reconstruction of the prominence structure is made using point-by-point triangulation. This is not possible for the August event due to a poor viewing geometry. Unlike the coronal mass ejection (CME) that accompanies it, the 2011 June prominence exhibits little deceleration from the Sun to 1 AU, as a consequence moving upwards within the CME. This demonstrates that prominences are not necessarily tied to the CME's magnetic structure far from the Sun. A mathematical framework is developed ...

  8. Modeling the Accretion Structure of AU Mon

    CERN Document Server

    Atwood-Stone, Corwin; Richards, Mercedes T; Budaj, Jan; Peters, Geraldine J

    2012-01-01

    AU Mon is a long-period (11.113 d) Algol-type binary system with a persistent accretion disk that is apparent as double-peaked H-alpha emission. We present previously unpublished optical spectra of AU Mon which were obtained over several years with dense orbital phase coverage. We utilize these data, along with archival UV spectra, to model the temperature and structure of the accretion disk and the gas stream. Synthetic spectral profiles for lines including H-alpha, H-beta, and the Al III and Si IV doublets were computed with the Shellspec program. The best match between the model spectra and the observations is obtained for an accretion disk of inner/outer radius 5.1/23 R_sun, thickness of 5.2 R_sun, density of 1.0e-13 g/cm^3, and maximum temperature of 14000 K, along with a gas stream at a temperature of ~8000 K transferring ~2.4e-9 M_sun/yr. We show H-alpha Doppler tomograms of the velocity structure of the gas, constructed from difference profiles calculated through sequentially subtracting contributions...

  9. Ordered arrays of Au catalysts by FIB assisted heterogeneous dewetting

    Science.gov (United States)

    Benkouider, A.; Ronda, A.; David, T.; Favre, L.; Abbarchi, M.; Naffouti, M.; Osmond, J.; Delobbe, A.; Sudraud, P.; Berbezier, I.

    2015-12-01

    Synthesizing Au0.8Si0.2 nanocatalysts that are homogeneous in size and have controlled position is becoming a challenging and crucial prequisite for the fabrication of ordered semiconductor nanowires. In this study, Au0.8Si0.2 nanocatalysts are synthesized via dewetting of Au layers on Si(111) during thermal annealing in an ultra-high vacuum. In the first part of the paper, the mechanism of homogeneous dewetting is analyzed as a function of the Au-deposited thickness (h Au). We distinguish three different dewetting regimes: (I) for a low thickness ({h}{{Au}}≤slant 0.4 {nm}), a submonolyer coverage of Au is stabilized and there is no dewetting. (II) For an intermediate thickness (0.4 {nm}\\lt {h}{Au}≤slant 5 {nm}), there is both dewetting and Au0.8Si0.2 phase formation. The size and density of the Au0.8Si0.2 clusters are directly related to h Au. When cooling down to room temperature, the clusters decompose and reject the Si at the Au/Si substrate interface. (III) For a large thickness ({h}{{Au}}\\gt 5 {nm}), only dewetting takes place, without forming AuSi clusters. In this regime, the dewetting is kinetically controlled by the self-diffusion of Au (activation energy ∼0.43 eV) without evidence of an Si-alloying effect. As a practical consequence, when relying solely on the homogeneous dewetting of Au/Si(111) to form the Au0.8Si0.2 catalysts (without a supply of Si atoms from vapor), regime II should be used to obtain good size and density control. In the second part of the paper, a process for ordering the catalysts using focused ion beam-(FIB) assisted dewetting (heterogeneous dewetting) is developed. We show that no matter what the FIB milling conditions and the Au nominal thickness are, dewetting is promoted by ion beam irradiation and is accompanied by the formation of Au0.8Si0.2 droplets. The droplets preferentially form on the patterned areas, while in similar annealing conditions, they do not form on the unpatterned areas. This behavior is attributed

  10. Coating of a layer of Au on Al13 : The findings of icosahedral Al@Al12Au20- and Al12Au202- fullerenes using ab initio pseudopotential calculations

    Science.gov (United States)

    Kumar, Vijay

    2009-02-01

    We report results of ab initio pseudopotential calculations on the nanocoating of gold on an icosahedral Al13 cluster and the findings of icosahedrally symmetric endohedral Al@Al12Au20- and empty cage Al12Au202- compound fullerenes formed of metal atoms. Twelve Al atoms cap the pentagonal faces of a dodecahedral Au20 cage in which each Au atom has three Al atoms and three Au atoms as nearest neighbors. Mixing of Al13 and Au20 magic clusters leads to a large heat of formation of 0.55 eV/atom and high stability of the Al@Al12Au20 compound fullerene. The binding energies of Al12Au20 and Al@Al12Au20 are 3.017 and 3.007 eV/atom, respectively, which are much larger than 2.457 eV/atom for Au32 fullerene, leading to the possibility of their high abundance.

  11. 197Au Moessbauer study of the deactivation and reactivation of a carbon-supported AuCl4- hydrochlorination catalyst

    International Nuclear Information System (INIS)

    Acetylene hydrochlorination catalysts consisting of activated carbon impregnated with a solution of HAuCl4.xH2O in aqua regia have been studied by 197Au Moessbauer spectroscopy. The relative amounts of AuCl4-, of Au(0), and of an Au(I) species formed under certain process conditions were determined quantitatively. Deactivation of the catalyst at low and high temperatures was shown to be due to different mechanisms, and the reactivation of the catalyst by Cl2 gas was studied. (orig.)

  12. Ultrafast charge carrier dynamics in Au/semiconductor nanoheterostructures

    Science.gov (United States)

    Lambright, Scott

    The charge carrier dynamics in several Au/semiconductor core/shell heterostructures were examined. Firstly, Au/CdS core/shell nanocomposites were synthesized in a four step procedure culminating in a cation exchange performed on the shell. Previous studies of the ultrafast carrier dynamics in Au/CdS nanocomposites with epitaxial boundary regions reported the suppression of plasmon character in transient absorption spectra accompanied by broadband photoinduced absorption. The coupling of electron wavefunctions with lattice defects at the boundary of the two domains has been blamed for these phenomena. In the current study, transmission electron micrographs of Au/CdS synthesized using cation exchange showed no evidence of strain on the lattice of either component, while femtosecond transient absorption data show the retention of bleach regions attributed to CdS's 1S(e)-1S3/2(h) transition and Au's plasmon resonance. Accelerated rates of bleach recovery for both excitations ( tauexiton ≈ 300 ps, tauplasmon ≈ .7 ps) indicated that the interaction of Au and CdS domains leads to faster relaxation to their respective photoexcitations when compared to relaxation times in isolated Au and CdS nanoparticles. It was believed that the Au/CdS boundary was non-epitaxial in the presented core/shell nanocomposites. Secondly, these non-epitaxial Au/CdS core/shells were subsequently used to demonstrate near-field energy transfer from 5 nm diameter Au cores to CdS-encapsulated CdSe quantum dots. To this end, Au/CdS and CdSe/CdS nanocrystals were embedded in semiconductor-matrix-encapsulated-nanocrystal-arrays (SMENA) together. The encapsulation of both domains in the high band-gap semiconductor CdS was a means to suppress charge transfer between the two nanoparticles. The fluorescence intensity in these films was enhanced 6-fold in some cases as a result of the presence of Au domains. It was also demonstrated that the fluorescence enhancement was independent of the potential

  13. Growth and structure of Co/Au magnetic thin films

    International Nuclear Information System (INIS)

    We have studied the growth and the crystallographic structure of magnetic ultra thin cobalt/gold films (Co/Au), in order to investigate the correlations between their magnetic and structural properties. Room temperature (R.T.) Co growth on Au (111) proceeds in three stages. Up to 2 Co monolayers (ML), a bilayer island growth mode is observed. Between 2 and 5 ML, coalescence of the islands occurs, covering the substrate surface and a Co/Au mixing is observed resulting from the de-construction of the Herringbone reconstruction. Finally, beyond 5 ML, the CoAu mixing is buried and the Co growth continues in a 3-D growth. Annealing studies at 600 K on this system show a smoothing effect of the Co film, and at the same time, segregation of Au atoms. The quality of the Co/Au interface (sharpness) is not enhanced by the annealing. The local order was studied by SEXAFS and the long range order by GIXRD showing that the Co film has a hexagonal close packed structure, with an easy magnetization axis perpendicular to the surface. From a local order point of view, the Co grows with an incoherent epitaxy and keeps its own bulk parameters. The GIXRD analysis shows a residual strain in the Co film of 4%. The difference observed between the local order analysis and the long range order results is explained in terms of the low dimensions of the diffracting domains. The evolution of film strains, as a function of the Co coverage, shows a marked deviation from the elastic strain theory. Modification of the strain field in the Co film as a function of the Au coverage is studied by GIXRD analysis. The Au growth study, at R.T., shows no evidence of a Au/Co mixing in the case of the Au/Co interface. The Au overlayer adopts a twinned face centred cubic structure on the rough Co film surface. (author)

  14. Gas phase selective hydrogenation over oxide supported Ni-Au.

    Science.gov (United States)

    Cárdenas-Lizana, Fernando; Keane, Mark A

    2015-11-14

    The chemoselective continuous gas phase (T = 573 K; P = 1 atm) hydrogenation of nitroarenes (p-chloronitrobenzene (p-CNB) and m-dinitrobenzene (m-DNB)) has been investigated over a series of oxide (Al2O3 and TiO2) supported Au and Ni-Au (1 : 10 mol ratio; 0.1-1 mol% Au) catalysts. Monometallic supported Au with mean particle size 3-9 nm promoted exclusive formation of p-chloroaniline (p-CAN) and m-nitroaniline (m-NAN). Selective hydrogenation rate was higher over smaller Au particles and can be attributed to increased surface hydrogen (from TPD measurements) at higher metal dispersion. (S)TEM analysis has confirmed an equivalent metal particle size for the supported bimetallics at the same Au loading where TPR indicates Ni-Au interaction and EDX surface mapping established Ni in close proximity to Au on isolated nanoparticles with a composition (Au/Ni) close to the bulk value (= 10). Increased spillover hydrogen due to the incorporation of Ni in the bimetallics resulted in elevated -NO2 group reduction rate. Full selectivity to p-CAN was maintained over all the bimetallic catalysts. Conversion of m-DNB over the lower loaded Ni-Au/Al2O3 generated m-NAN as sole product. An increase in Ni content (0.01 → 0.1 mol%) or a switch from Al2O3 to TiO2 as support resulted in full -NO2 reduction (to m-phenylenediamine). Our results demonstrate the viability of Ni-promotion of Au in the continuous production of functionalised anilines. PMID:25752655

  15. Balance functions from Au+Au, d+Au, and p+p collisions at sqrt(s)NN=200 GeV

    OpenAIRE

    Aggarwal, M. M.; Braidot, E.; Mischke, A.; Peitzmann, T.(Institute for Subatomic Physics of Utrecht University, Utrecht, Netherlands); van Leeuwen, M.(Institute for Subatomic Physics of Utrecht University, Utrecht, Netherlands)

    2010-01-01

    Balance functions have been measured for charged-particle pairs, identified charged-pion pairs, and identified charged-kaon pairs in Au+Au, d+Au, and p+p collisions at √sNN=200 GeV at the Relativistic Heavy Ion Collider using the STAR detector. These balance functions are presented in terms of relative pseudorapidity, Δη, relative rapidity, Δy, relative azimuthal angle, Δϕ, and invariant relative momentum, qinv. For charged-particle pairs, the width of the balance function in terms of Δη scal...

  16. Mixed Valent Gold Oxides: Syntheses, Structures, and Properties of Rb 5Au 3O 2, Rb 7Au 5O 2, and Cs 7Au 5O 2

    Science.gov (United States)

    Mudring, Anja-Verena; Nuss, Jürgen; Wedig, Ulrich; Jansen, Martin

    2000-11-01

    The title compounds Rb5Au3O2, Rb7Au5O2, and Cs7Au5O2 are the first examples of mixed valent phases containing gold in the oxidation states +1 and -1. Their crystal structures (Rb5Au3O2, Pbam, a=736.4(1) pm, b=1430.8(2) pm, c=567.9(1) pm, Z=2, R(F)=0.053, 647 reflections; Rb7Au5O2, Immm, a=567.1(2) pm, b=930.1(1) pm, C=1659.4(3) pm, Z=2, R(F)=0.066, 409 reflections; Cs7Au5O2, Immm, a=599.4(1) pm, b=960.6(3) pm, c=1720.8(12) pm, Z=2, R(F)=0.039, 386 reflections) are characterized by the combination of distinctive structural features of gold(I) oxides and aurides: for Au(+1) a typical linear coordination by oxygen is found and the surroundings of Au(-1) bear a close resemblance to the binary 1:1 aurides. In consequence the overall structures of Rb5Au3O2 and M7Au5O2 can be described as intergrowths of M3AuO2 and MAu (M=Rb, Cs), constituting members of a homologous series [MAu]n[M3AuO2] with n=2 and 4, respectively. The crystal chemical evidence for the valence states assumed, also confirmed by Mößbauer spectroscopy, is supported by various band structure calculations (Hartee-Fock and density functional) clearly indicating the coexistence of two different oxidation states. The compounds have been synthesized by reacting binary aurides MAu and alkali monoxides M2O (M=Rb, Cs) with elemental gold in the required stochiometric amounts. Hereby, a further astonishing parallel to the chemistry of halogens is revealed. Like these, gold disproportionates upon interaction with bases.

  17. Resonance production and exotic clusters in Au+Au, d+Au and p+p collisions at √(s) = 200 AGeV

    International Nuclear Information System (INIS)

    The resonance production in Au+Au, d+Au and p+p collisions at √(s) = 200 AGeV are presented. The resonances are used as a sensitive tool to examine the collision dynamics in the hadronic medium through their decay and regeneration. The modification of resonance mass, width, and shape due to phase space and dynamical effects are also discussed. The measurement of resonances provides an important tool for studying the dynamics in relativistic heavy-ion collisions by probing the time evolution of the source from chemical to kinetic freeze-out and the hadronic interactions at later stages

  18. EFFECT OF LASER INPUT ENERGY ON AuSnx INTERMETALLIC COMPOUNDS FORMATION IN SOLDER JOINTS WITH DIFFERENT THICKNESS OF Au SURFACE FINISH ON PADS

    Institute of Scientific and Technical Information of China (English)

    W.Liu; C.Q.Wang; Y.H.Tian; M.Y.Li

    2008-01-01

    Formation of AuSnx intermetallic compounds (IMCs) in laser reflowed solder joints was investigated. The results showed that few IMCs formed at the solder/0.1 μm Au interface. Needlelike AuSn4 IMCs were observed at the solder/0.5 μm Au interface.In Sn-2.0Ag-0.75Cu-3.0Bi and Sn-3.5Ag-O.75Cu solder joints, when the laser input energy was increased, AuSn4 IMCs changed from a layer to needlelike or dendritic distribution at the solder/0.9 μm Au interface. As for the solder joints with 4.0 μm thickness of Au surface finish on pads, AuSn4 , AuSn2, AuSn IMCs, and Au2 Sn phases formed at the interface. Moreover, the content of AuSnx IMCs, such as, AuSn4 and AuSn2, which contained high Sn concentration, would become larger as the laser input energy increased. In the Sn-37Pb solder joints with 0.9 μm or 4.0 μm thickness of the Au surface finish on pads, AuSn4 IMCs were in netlike distribution. The interspaces between them were filled with Pb-rich phases.

  19. Magnetic order of Au nanoparticle with clean surface

    International Nuclear Information System (INIS)

    Au nanoparticles, which are kept in vacuum after the preparation by gas evaporation method, show ferromagnetism even in 1.7 nm in diameter. The intrinsic magnetism is examined by detecting the disappearance of spontaneous magnetization in Au bulk prepared by heating the nanoparticles without exposure to the air. The temperature dependence of spontaneous magnetization is not monotonic and the increase in magnetization is observed after Au nanoparticles are exposed to the air. The magnetic behavior can be interpreted by the ferrimagnetic-like core–shell structure with shell thickness of 0.16±0.01 nm and magnetic moment of (1.5±0.1)×10−2 μB/Au atom, respectively. - Highlights: • Au nanoparticles with clean surface were prepared by the gas evaporation method. • The spontaneous magnetization was observed in Au nanoparticles. • Temperature dependent spontaneous magnetization of smaller Au particles was not monotonic. • The magnetic behavior was interpreted by the ferrimagnetic-like core–shell model. • The shell thickness and the magnetic moment per Au atom were estimated

  20. Lessons learned from AU PSO-missions in Africa

    DEFF Research Database (Denmark)

    Mandrup, Thomas

    The paper deals with the lessons learned from AU's PSO since 2002, and what that entails for the design of future PSO.......The paper deals with the lessons learned from AU's PSO since 2002, and what that entails for the design of future PSO....

  1. MACHINE ELECTRIQUE TOURNANTE POLYPHASEE A AU MOINS CINQ PHASES

    OpenAIRE

    ASLAN, Bassel; SEMAIL, Eric; LEGRANGER, Jerome

    2013-01-01

    Ce brevet s'est opéré dans le cadre de la thèse d'Aslan Bassel au Laboratoire L2EP avec VALEO dans le cadre du projet MHYGALE financé par l'ADEME, avec VALEO responsable du consortium. Le brevet est déposé au nom de VALEO EQUIPEMENTS ELECTRIQUES MOTEUR.

  2. Microstructural evolution of eutectic Au-Sn solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ho Geon

    2002-05-31

    Current trends toward miniaturization and the use of lead(Pb)-free solder in electronic packaging present new problems in the reliability of solder joints. This study was performed in order to understand the microstructure and microstructural evolution of small volumes of nominally eutectic Au-Sn solder joints (80Au-20Sn by weight), which gives insight into properties and reliability.

  3. Magnetic order of Au nanoparticle with clean surface

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Ryuju; Ishikawa, Soichiro; Sato, Hiroyuki; Sato, Tetsuya, E-mail: satoh@appi.keio.ac.jp

    2015-11-01

    Au nanoparticles, which are kept in vacuum after the preparation by gas evaporation method, show ferromagnetism even in 1.7 nm in diameter. The intrinsic magnetism is examined by detecting the disappearance of spontaneous magnetization in Au bulk prepared by heating the nanoparticles without exposure to the air. The temperature dependence of spontaneous magnetization is not monotonic and the increase in magnetization is observed after Au nanoparticles are exposed to the air. The magnetic behavior can be interpreted by the ferrimagnetic-like core–shell structure with shell thickness of 0.16±0.01 nm and magnetic moment of (1.5±0.1)×10{sup −2} μ{sub B}/Au atom, respectively. - Highlights: • Au nanoparticles with clean surface were prepared by the gas evaporation method. • The spontaneous magnetization was observed in Au nanoparticles. • Temperature dependent spontaneous magnetization of smaller Au particles was not monotonic. • The magnetic behavior was interpreted by the ferrimagnetic-like core–shell model. • The shell thickness and the magnetic moment per Au atom were estimated.

  4. Microstructural evolution of eutectic Au-Sn solder joints

    OpenAIRE

    Song, Ho Geon

    2002-01-01

    Current trends toward miniaturization and the use of lead(Pb)-free solder in electronic packaging present new problems in the reliability of solder joints. This study was performed in order to understand the microstructure and microstructural evolution of small volumes of nominally eutectic Au-Sn solder joints (80Au-20Sn by weight), which gives insight into properties and reliability.

  5. Growth and structure of Co/Au magnetic thin films; Croissance et structure des couches minces magnetiques Co/Au

    Energy Technology Data Exchange (ETDEWEB)

    Marsot, N

    1999-01-14

    We have studied the growth and the crystallographic structure of magnetic ultra thin cobalt/gold films (Co/Au), in order to investigate the correlations between their magnetic and structural properties. Room temperature (R.T.) Co growth on Au (111) proceeds in three stages. Up to 2 Co monolayers (ML), a bilayer island growth mode is observed. Between 2 and 5 ML, coalescence of the islands occurs, covering the substrate surface and a Co/Au mixing is observed resulting from the de-construction of the Herringbone reconstruction. Finally, beyond 5 ML, the CoAu mixing is buried and the Co growth continues in a 3-D growth. Annealing studies at 600 K on this system show a smoothing effect of the Co film, and at the same time, segregation of Au atoms. The quality of the Co/Au interface (sharpness) is not enhanced by the annealing. The local order was studied by SEXAFS and the long range order by GIXRD showing that the Co film has a hexagonal close packed structure, with an easy magnetization axis perpendicular to the surface. From a local order point of view, the Co grows with an incoherent epitaxy and keeps its own bulk parameters. The GIXRD analysis shows a residual strain in the Co film of 4%. The difference observed between the local order analysis and the long range order results is explained in terms of the low dimensions of the diffracting domains. The evolution of film strains, as a function of the Co coverage, shows a marked deviation from the elastic strain theory. Modification of the strain field in the Co film as a function of the Au coverage is studied by GIXRD analysis. The Au growth study, at R.T., shows no evidence of a Au/Co mixing in the case of the Au/Co interface. The Au overlayer adopts a twinned face centred cubic structure on the rough Co film surface. (author)

  6. Formation of CuxAu1−x phases by cold homogenization of Au/Cu nanocrystalline thin films

    Directory of Open Access Journals (Sweden)

    Alona Tynkova

    2014-09-01

    Full Text Available It is shown, by using depth profiling with a secondary neutral mass spectrometer and structure investigations by XRD and TEM, that at low temperatures, at which the bulk diffusion is frozen, a complete homogenization can take place in the Cu/Au thin film system, which leads to formation of intermetallic phases. Different compounds can be formed depending on the initial thickness ratio. The process starts with grain boundary interdiffusion, which is followed by a formation of reaction layers at the grain boundaries that leads to the motion of the newly formed interfaces perpendicular to the grain boundary plane. Finally, the homogenization finishes when all the pure components have been consumed. The process is asymmetric: It is faster in the Au layer. In Au(25nm/Cu(50nm samples the final state is the ordered AuCu3 phase. Decrease of the film thicknesses, as expected, results in the acceleration of the process. It is also illustrated that changing the thickness ratio either a mixture of Cu-rich AuCu and AuCu3 phases (in Au(25nm/Cu(25nm sample, or a mixture of disordered Cu- as well as Au-rich solid solutions (in Au(25nm/Cu(12nm sample can be produced. By using a simple model the interface velocity in both the Cu and Au layers were estimated from the linear increase of the average composition and its value is about two orders of magnitude larger in Au (ca. 10−11 m/s than in Cu (ca. 10−13 m/s.

  7. Viscoelastic nature of Au nanoparticle–PDMS nanocomposite gels

    Indian Academy of Sciences (India)

    Ritu Gupta; Hima K Nagamanasa; Rajesh Ganapathy; Giridhar U Kulkarni

    2015-08-01

    A stable gel of Au nanoparticles in polydimethylsiloxane (PDMS) nanocomposite is prepared by employing the curing agent of PDMS elastomer as a reducing agent for the formation of Au nanoparticles by an in-situ process. The viscoelastic nature of these gels is very sensitive to the Au nanoparticle loading and the synthetic temperature conditions. Even a very low Au content of 0.09 wt% is sufficient enough to bring in the transition from sponge state to gel state at room temperature. Higher synthetic temperature also forms sponge formation. Infrared and ultraviolet–visible spectroscopy measurements have provided insight into PDMS crosslinking and nanoparticle formation, respectively. The optimization of the gel properties can have direct influence on the processability of Au nanoparticle–PDMS nanocomposite gels, with interesting implications in electronic, optical and microfluidic devices.

  8. Synthesis and characterization of Au-alumina nanocomposites prepared by atom beam co-sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, Manisha; Annapoorni, S. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Agarwal, D.C.; Avasthi, D.K. [Inter University Accelerator Centre, P.O. Box 10502, New Delhi 110067 (India); Mohapatra, S. [School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Dwarka, New Delhi 110075 (India); Pivin, J.C. [CSNSM, IN2P3-CNRS, Batiment 108, 1405 Orsay Campus (France)

    2012-12-15

    Nanocomposite thin films of Au-alumina with varying Au contents were synthesized by atom beam co-sputtering. The Au content and the thickness of nanocomposite films were determined by Rutherford backscattering spectrometry. Transmission electron microscopy studies reveal the presence of Au nanoparticles with bimodal size distribution in nanocomposites for lower Au content. Overlapping Au nanoparticles were observed for higher Au content. The increase in size of Au nanocrystals is observed with increase in Au concentration as also evident by glancing angle X-ray diffraction studies. Ultraviolet (UV)-visible absorption studies revealed surface plasmon resonance (SPR) peak which showed a red shift from 519 to 602 nm with increasing Au content of the nanocomposites. Preliminary study exploring the interaction between Au nanoparticles in the nanocomposites and bovine serum albumin (BSA) showed the Au nanoparticles to be BSA sensitive, indicating their possible applications in biosensors. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Contribution au SAR spatial distribué

    OpenAIRE

    Maréchal, Rozenn

    2006-01-01

    L'obtention d’images à partir de l'émission, de la réception et du traitement d'impulsions radar (SAR) est soumise à différentes contraintes qui limitent les performances telles que la résolution en distance, la résolution en azimut ou la largeur de la Zone imagée (fauchée). Ces limites sont en partie liées à la dimension finie de l’antenne, en particulier dans le cas du SAR spatial. Pour cette raison, on a cherché à étudier la possibilité de mettre au point des systèmes SAR spatiaux distribué...

  10. The AuScope Geodetic VLBI Array

    CERN Document Server

    Lovell, J E J; Reid, P B; McCulloch, P M; Baynes, B E; Dickey, J M; Shabala, S S; Watson, C S; Titov, O; Ruddick, R; Twilley, R; Reynolds, C; Tingay, S J; Shield, P; Adada, R; Ellingsen, S P; Morgan, J S; Bignall, H E; 10.1007/s00190-013-0626-3

    2013-01-01

    The AuScope geodetic Very Long Baseline Interferometry array consists of three new 12 m radio telescopes and a correlation facility in Australia. The telescopes at Hobart (Tasmania), Katherine (Northern Territory) and Yarragadee (Western Australia) are co-located with other space geodetic techniques including Global Navigation Satellite Systems (GNSS) and gravity infrastructure, and in the case of Yarragadee, Satellite Laser Ranging (SLR) and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) facilities. The correlation facility is based in Perth (Western Australia). This new facility will make significant contributions to improving the densification of the International Celestial Reference Frame in the Southern Hemisphere, and subsequently enhance the International Terrestrial Reference Frame through the ability to detect and mitigate systematic error. This, combined with the simultaneous densification of the GNSS network across Australia will enable the improved measurement of intrapl...

  11. De l’invisible au visible

    OpenAIRE

    Tellier, Thibault

    2009-01-01

    Si la place qu’occupent les jeunes d’origine immigrée dans le traitement médiatique des violences urbaines dans certaines cités HLM n’est plus à démontrer, on connaît en revanche beaucoup moins bien la prise en compte de la  pratique religieuse des populations d’origine immigrée durant les années 1970-1990. Cette communication a donc pour but de montrer, à partir de l’exemple des grands ensembles, comment s’est effectuée au cours des Trente Glorieuses la prise en compte spécifique de cette pr...

  12. La géographie au sommet

    OpenAIRE

    Denise Pumain

    2002-01-01

    Le Ministre de l’Environnement d’Afrique du sud annonçant le sommet de Johannesburg, saluait l’occasion ainsi donnée à l’humanité de revenir au continent de ses origines pour ouvrir une ère nouvelle de solidarité (CityPress du 11 aôut). Quelques jours avant, les géographes de l’Union Géographique Internationale réunis pour leur « conférence régionale » à Durban sur le thème de « la renaissance de la géographie à l’aube du troisième millénaire » avaient invité Nelson Mandela. A cette occasion,...

  13. La Physique au LHC - Partie I

    CERN Document Server

    CERN. Geneva

    2004-01-01

    Le LHC devrait permettre l'observation du boson de Higgs et pouvoir lever le voile sur l'un des scénarios de nouvelle physique présentés dans la cours précédent. Ce cours détaillera les perspectives de physique au LHC (découvertes possibles et mesures de précision) ainsi que les méthodes et difficultés expérimentales. L'accent sera mis sur les problèmes liés à la brisure de la symétrie electrofaible. Les possibilités de développement futur à plus haute luminosité et/ou énergie seront également discutées.

  14. Musique ! : du phonographe au MP3

    OpenAIRE

    Tournès, Ludovic

    2011-01-01

    nouvelle édition revue et augmentée de "Du phonographe au MP3. Une histoire de la musique enregistrée, XIXe-XXIe siècle" [2008] Depuis l'invention du phonographe par Thomas Edison en 1877, jusqu'à la révolution Internet, la musique enregistrée a connu une histoire longue et riche en rebondissements que l'on trouvera retracée de manière claire, synthétique et vivante dans ce livre. A l'heure où l'industrie de la musique est engagée depuis le début des années 2000 dans une mutation historiqu...

  15. Jusqu’au ciel !

    OpenAIRE

    de Coster, Xavier

    2014-01-01

    Le récit biblique de la Tour de Babel (Gn. XI : 1-9) dit que le sommet de celle-ci devait atteindre les cieux. Ce texte a inspiré de nombreux artistes, au premier rang desquels Pieter Bruegel l'Ancien. Cet article s'intéresse à la manière dont parmi eux quelques prédécesseurs de Bruegel, puis lui-même, ont représenté le ciel, lequel joue dans cette histoire un rôle fondamental : non seulement le ciel est le but que se sont assigné les constructeurs de la tour, mais c'est du ciel que vient la ...

  16. TOZY (Mohammed), Monarchie et islam au Maroc

    OpenAIRE

    Elahmadi, Mohsine

    2009-01-01

    114.44 L’auteur de ce livre est professeur de Sciences Politiques à la Faculté de Droit Aïn-Chok à Casablanca. Ancien étudiant et fidèle disciple de Bruno Étienne, il est connu notamment pour sa fameuse thèse de doctorat d’État portant le titre de « Champ et contre-champ politico-religieux au Maroc ». En fait, il faut lire Monarchie et islam politique (désormais : M. I. P.) à la lumière de cette thèse pour suivre le fil conducteur de l’ensemble de ses recherches. En effet, ce livre se divise ...

  17. Incomplete melting of the Au(100) surface

    International Nuclear Information System (INIS)

    We study the high-temperature disordering of the reconstructed Au(100) surface by molecular dynamics simulation using a many-body interatomic potential. We find that the surface deconstructs at 0.8Tm in good agreement with experimental data, but proper surface melting does not occur close to the bulk melting point. Instead there is an in-plane disordering of the two topmost layers. The thickness of the disordered region remains constant with increasing temperature, indicating blocked, or incomplete, melting of the (100) crystalline substrate. An analysis of the structure reveals that crystalline and disordered islands coexist on two first surface layers for temperature between deconstruction and bulk melting. (author). 24 refs, 10 figs

  18. Prominent transverse flow of clusters in stopped Au(150AMeV)+Au reactions

    International Nuclear Information System (INIS)

    Stopped Au(150AMeV)+Au collisions have been measured with the FOPI-Detector at GSI by imposing an upper limit on the ratio of the global longitudinal momentum to the collected charge within an event. The ejectiles, in particular those with Z>3, have a rapidity close to mid-rapidity and exhibit angular distributions in the centre-of-mass strongly peaking around 90 thus suggesting an enhancement of the flow in the transverse direction. Fits to the data and comparisons with QMD calculations indicate an averaged collective velocity in the transverse direction equal to 0.12c. Significance of the determined velocity and temperature values is discussed. ((orig.))

  19. Questions croisées au sujet du documentaire Droit au but

    OpenAIRE

    Bromberger, Christian; Costantini, Philippe; Accolas, Sophie

    2015-01-01

    Sophie Accolas – Comment, à votre avis, le cinéma contemporain aborde‑t‑il le sport au regard de la globalisation ? Christian Bromberger – Il y a deux façons d’envisager la question. Soit l’on englobe dans la production cinématographique les matchs filmés et diffusés à la télévision, soit on ne retient que les films documentaires et de fiction. Dans la première hypothèse, on voit bien quel rôle joue l’image sportive dans le monde contemporain et, comme vous dites, « au regard de la globalisa...

  20. On the thermalization of dense hadronic matter in Au + Au collisions at FAIR

    CERN Document Server

    De, Somnath; Chattopadhyay, Subhasis

    2015-01-01

    The conditions of local thermodynamic equilibrium of baryons (non-strange, strange) and mesons (strange) are presented for central Au + Au collisions at FAIR energies using the microscopic transport model UrQMD. The net particle density, longitudinal-to-transverse pressure anisotropy and inverse slope parameters of the energy spectra of non-strange and strange hadrons are calculated inside a cell in the central region within rapidity window $|y| < 1.0$ at different time steps after the collision. We observed that the strangeness content is dominated by baryons at all energies, however contribution from mesons become significant at higher energies. The time scale obtained from local pressure (momentum) isotropization and thermalization of energy spectra are nearly equal and found to decrease with increase in laboratory energy. The equilibrium thermodynamic properties of the system are obtained with statistical thermal model. The time evolution of the entropy densities at FAIR energies are found very similar...

  1. Propagation of Fluctuations in Au+Au Collisions at FAIR energy

    CERN Document Server

    Ahmad, S; Bashir, S; jahan, H; Ahmad, N; Chattopadhyay, S

    2014-01-01

    Event by event fluctuations of particle multiplicities and their ratios are considered to be sensitive probes to the exotic phenomena in high energy heavy ion collisions like phase transtion or the occurence of critical point. These phenomena might take place at different time after the collision based on fulfilling the required conditions at a particular time. Fluctuations are therefore expected to show non-monotonic behaviour at the of time of occurence of these phenomena. Experimentally, fluctuations are measured at freezeout. In this work, using the hybrid version of the UrQMD event generator, we have investigated the propagation of fluctuations of particle multiplicities, their ratios and the ratio of total positive and negative charges in AuAu collisions at E_{lab} < 90 AGeV. Two commonly used experimental measures i.e., {\\sigma^2}/mean and {\

  2. Nuclear Shadowing Effect on the K Factor in Au-Au Collisions

    Institute of Scientific and Technical Information of China (English)

    侯召宇; 郑乔; 张本爱

    2002-01-01

    We investigate the nuclear shadowing effect on the K factor in the Drell-Yan process by introducing a shadowing factor into the corresponding quantum chromodynamical αs order corrections. K factors for Au-Au collisions are calculated at the centre-of-mass system energies √s = 60, 130 and 200 GeV while the nuclear shadowing factor is taken into account. The numerical results indicate that the nuclear shadowing factor obviously raises the K value in the small x region, and for the same nucleon the K value becomes smaller as the energy increases. The nuclear shadowing effect could be one reason for creating the non-constancy of the K factor.

  3. Musique populaire et musique savante au XIXe siècle. Du "peuple" au "public"

    OpenAIRE

    Leterrier, Sophie-Anne

    2008-01-01

    La production culturelle englobe des formes musicales dont les statuts sont très variés. La chanson du colporteur et la partition symphonique n'appartiennent pas au même "genre" ni par leurs conditions de production, i par leurs formes matérielles, leur circulation, leur public, leur postérité. À ce sujet, l'étude des évolutions en cours au XIXe siècle est intéressante de plusieurs points de vue. D'abord, parce que c'est alors que les institutions destinées à former des "spécialistes" de la m...

  4. Reviewing hadron production at SIS energies featuring the new HADES Au+Au data

    International Nuclear Information System (INIS)

    We present the first preliminary results on the production of hadrons with strangeness content (K+, K−, Ks0, Λ and ϕ) in Au+Au collisions at 1.23 A GeV incident energy measured with HADES. At the corresponding center of mass energy of √(s)=2.4 GeV all hadrons carrying strangeness are produced below their free nucleon–nucleon threshold. While the K−/K+ ratio nicely fits the trend observed at higher energies, we find a strong rise of the ϕ/K− ratio. The presented particle ratios are compared to a statistical model fit and put into the context of previously obtained systematics on strangeness production

  5. Beam Energy Dependence of Dielectron Production in Au+Au Collisions from STAR at RHIC

    CERN Document Server

    Huck, Patrick

    2014-01-01

    We present the energy-dependent study of dielectron production in 0-80% minimum-bias Au+Au collisions at $\\sqrt{s_{NN}}$ energies of 19.6, 27, 39, and 62.4 GeV in STAR. Invariant mass ($M_{ee}$) and transverse momentum ($p_T$) differential measurements of dielectron yields are compared to cocktail simulations of known hadronic sources and semi-leptonic charmed decays. The enhancement (excess yield) prominent in the Low-Mass Region (LMR) over the cocktail at all energies, is further compared to calculations of $\\rho$ in-medium modifications. Within statistical and systematic uncertainties, we find that the model consistently describes this enhancement from SPS up to top RHIC energies in its $M_{ee}$- as well as $p_T$-dependence. Dielectron measurements drive the statistics for the future BES Phase-II program, which promises to improve our understanding of the LMR enhancement's trend with total baryon densities.

  6. Collective effects in Au(100-800 AMeV) + Au semi-central collisions

    International Nuclear Information System (INIS)

    The present work has been carried out in the framework of the experimental program of the FOPI collaboration. It is devoted to a systematic study of the different forms of collective expansion of nuclear matter in semi-central Au+Au collisions at incident energies ranging from 100 AMeV to 800 AMeV. The aim is to investigate the influence of compressional effects, momentum dependence of the nuclear interaction and nucleon-nucleon cross section on the observed phenomena. Important changes in the reaction mechanisms are evidenced, in particular at low incident energies where one observes, on the one hand, a transition from an enhanced in-plane emission to a preferential out-of-plane emission pattern and, on the other hand, a strong reduction of the directed in-plane component. Experimental results are compared to the predictions of the Quantum Molecular Dynamics (QMD) model for different parametrizations of the nuclear interaction. (author)

  7. Dynamical approach to spectator fragmentation in Au+Au reactions at 35 MeV/A

    CERN Document Server

    Vermani, Yogesh K

    2010-01-01

    The characteristics of fragment emission in peripheral $^{197}$Au+$^{197}$Au collisions 35 MeV/A are studied using the two clusterization approaches within framework of \\emph{quantum molecular dynamics} model. Our model calculations using \\emph{minimum spanning tree} (MST) algorithm and advanced clusterization method namely \\emph{simulated annealing clusterization algorithm} (SACA) showed that fragment structure can be realized at an earlier time when spectators contribute significantly toward the fragment production even at such a low incident energy. Comparison of model predictions with experimental data reveals that SACA method can nicely reproduce the fragment charge yields and mean charge of the heaviest fragment. This reflects suitability of SACA method over conventional clusterization techniques to investigate spectator matter fragmentation in low energy domain.

  8. Azimuthal anisotropy in Au+Au collisions at √sNN = 200 GeV

    International Nuclear Information System (INIS)

    The results from the STAR Collaboration on directed flow (v1), elliptic flow (v2), and the fourth harmonic (v4) in the anisotropic azimuthal distribution of particles from Au+Au collisions at √sNN = 200 GeV are summarized and compared with results from other experiments and theoretical models. Results for identified particles are presented and fit with a Blast Wave model. For v2, scaling with the number of constituent quarks and parton coalescence is discussed. For v4, scaling with v22 and quark coalescence predictions for higher harmonic flow is discussed. The different anisotropic flow analysis methods are compared and nonflow effects are extracted from the data. For v2, scaling with the number of constituent quarks and parton coalescence are discussed. For v22 and quark coalescence are discussed

  9. Local structure of disordered Au-Cu and Au-Ag alloys

    International Nuclear Information System (INIS)

    X-ray-absorption fine structure (XAFS) and x-ray-diffraction (XRD) measurements of disordered alloys AuxCu1-x and Au0.5Ag0.5 prepared by melt spinning were performed. In the Au0.5Ag0.5 alloy, no significant local deviations of the atoms from the average fcc lattice were detected while in AuxCu1-x alloys, significant deviations of atoms from the average fcc lattice were found. Mean-square vibrations of the Cu-Cu distances revealed by the XAFS in AuxCu1-x alloys indicate the weakening of contact between Cu atoms in the dilute limit. Our computer simulation for AuxCu1-x clusters of 105 atoms reproduces the main features of both the XAFS and XRD data

  10. On Productions of Net-baryons in Central Au-Au Collisions at RHIC Energies

    CERN Document Server

    Chen, Ya-Hui; Liu, Fu-Hu

    2015-01-01

    The transverse momentum and rapidity distributions of net-baryons (baryons minus anti-baryons) produced in central gold-gold (Au-Au) collisions at 62.4 and 200 GeV are analyzed in the framework of a multisource thermal model. Each source in the model is described by the Tsallis statistics to extract the effective temperature and entropy index from the transverse momentum distribution. The two parameters are used as input to describe the rapidity distribution and to extract the rapidity shift and contribution ratio. Then, the four types of parameters are used to structure some scatter plots of the considered particles in some three-dimensional (3D) spaces at the stage of kinetic freeze-out, which are expected to show different characteristics for different particles and processes. The related methodology can be used in the analyzes of particle production and event holography, which are useful for us to better understand the interacting mechanisms.

  11. Azimuthal anisotropy in Au+Au collisions at sqrtsNN = 200 GeV

    CERN Document Server

    Adams, J; Ahammed, Z; Amonett, J; Anderson, B D; Arkhipkin, D; Averichev, G S; Badyal, S K; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bezverkhny, B I; Bharadwaj, S; Bhasin, A; Bhati, A K; Bhatia, V S; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Brandin, A V; Bravar, A; Bystersky, M; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca-Sanchez, M; Carroll, J; Castillo, J; Cebra, D; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; De Moura, M M; Derevshchikov, A A; Didenko, L; Dietel, T; Dogra, S M; Dong, W J; Dong, X; Draper, J E; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta-Majumdar, M R; Eckardt, V; Edwards, W R; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Faivre, J; Fatemi, R; Fedorisin, J; Filimonov, K; Filip, P; Finch, E; Fine, V; Fisyak, Yu; Foley, K J; Fomenko, K; Fu, J; Gagliardi, C A; Gans, J; Ganti, M S; Gaudichet, L; Geurts, F J M; Ghazikhanian, V; Ghosh, P; González, J E; Grachov, O; Grebenyuk, O; Grosnick, D P; Guertin, S M; Guo, Y; Sen-Gupta, A; Gutíerrez, T D; Hallman, T J; Hamed, A; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Hepplemann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Huang, H Z; Huang Sheng Li; Hughes, E W; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Janik, M; Jiang, H; Jones, P G; Judd, E G; Kabana, S; Kang, K; Kaplan, M; Keane, D; Khodyrev, V Yu; Kiryluk, J; Kisiel, A; Kislov, E M; Klay, J; Klein, S R; Klyachko, A; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Krämer, M; Kravtsov, P; Kravtsov, V I; Krüger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunz, C L; Kutuev, R K; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Lehocka, S; Le Vine, M J; Li, C; Li, Q; Li, Y; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Q J; Liu, Z; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; López-Noriega, M; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, J G; Ma, Y G; Magestro, D; Mahajan, S; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J N; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Meissner, F; Melnik, Yu M; Meschanin, A; Miller, M L; Milosevich, Z; Minaev, N G; Mironov, C; Mischke, A; Mishra, D K; Mitchell, J; Mohanty, B; Molnár, L; Moore, C F; Morozov, D A; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Netrakanti, P K; Nikitin, V A; Nogach, L V; Nurushev, S B; Odyniec, Grazyna Janina; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Pal, S K; Panebratsev, Yu A; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Peitzmann, Thomas; Perevozchikov, V; Perkins, C; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M V; Potrebenikova, E V; Potukuchi, B V K S; Prindle, D; Pruneau, C A; Putschke, J; Rai, G; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D M; Reid, J G; Renault, G; Retière, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Schröder, L S; Schweda, K; Seger, J; Seyboth, P; Shahaliev, E; Shao, M; Shao, W; Sharma, M; Shen, W Q; Shestermanov, K E; Shimansky, S S; Sichtermann, E P; Simon, F; Singaraju, R N; Skoro, G P; Smirnov, N; Snellings, R; Sood, G; Sørensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Stock, R; Stolpovsky, A; Strikhanov, M N; Stringfellow, B C; Suaide, A A P; Sugarbaker, E R; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Tarnowsky, T J; Thein, D; Thomas, J H; Timoshenko, S; Tokarev, M; Trainor, T A; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Urkinbaev, A R; Van Buren, G; Van, M; Leeuwen; Van der Molen, A M; Varma, R; Vasilevski, I M; Vasilev, A N; Vernet, R; Vigdor, S E; Viyogi, V P; Vokal, S; Voloshin, S A; Vznuzdaev, M; Waggoner, W T; Wang, F; Wang, G; Wang, G; Wang, X L; Wang, Y; Wang, Y; Wang, Z M; Ward, H; Watson, J W; Webb, J C; Wells, R; Westfall, G D; Wetzler, A; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yamamoto, E; Yepes, P; Yurevich, V I; Zanevsky, Yu V; Zhang, H; Zhang, W M; Zhang, Z P; Zolnierczuk, P A; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N

    2004-01-01

    The results from the STAR Collaboration on directed flow ($v_1$), elliptic flow ($v_2$), and the fourth harmonic ($v_4$) in the anisotropic azimuthal distribution of particles from Au+Au collisions at $\\sqrtsNN = 200$ GeV are summarized and compared with results from other experiments and theoretical models. Results for identified particles are presented and fit with a Blast Wave model. For $v_2$, scaling with the number of constituent quarks and parton coalescence is discussed. For $v_4$, scaling with $v_2^2$ and quark coalescence predictions for higher harmonic flow is discussed. The different anisotropic flow analysis methods are compared and nonflow effects are extracted from the data.

  12. Directed flow in Au+Au collisions at $\\sqrt{s_{_{NN}}}$ =62 GeV

    CERN Document Server

    Keane, D; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Arkhipkin, D; Averichev, G S; Badyal, S K; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellingeri-Laurikainen, A; Bellwied, R; Berger, J; Bezverkhny, B I; Bharadwaj, S; Bhasin, A; Bhati, A K; Bhatia, V S; Bichsel, H; Bielcik, J; Bielcikova, J; Billmeier, A; Bland, L C; Blyth, C O; Blyth, S L; Bonner, B E; Botje, M; Boucham, A; Bouchet, J; Brandin, A V; Bravar, A; Bystersky, M; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca-Sanchez, M; Castillo, J; Catu, O; Cebra, D; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, Y; Cheng, J; Cherney, M; Chikanian, A; Choi, H 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; De Phillips, M; Dedovich, T G; Derevshchikov, A A; Didenko, L; Dietel, T; Dogra, S M; Dong, W J; Dong, X; Draper, J E; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta-Majumdar, M R; Eckardt, V; Edwards, W R; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Faivre, J; Fatemi, R; Fedorisin, J; Filimonov, K; Filip, P; Finch, E; Fine, V; Fisyak, Yu; Fornazier, K S F; Fu, J; Gagliardi, C A; Gaillard, L; Gans, J; Ganti, M S; Geurts, F; Ghazikhanian, V; Ghosh, P; González, J E; Gos, H; Grachov, O; Grebenyuk, O; Grosnick, D P; Guertin, S M; Guo, Y; Gupta, N; Gutíerrez, T D; Hallman, T J; Hamed, A; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Hepplemann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horner, M J; Huang, H Z; Huang, S L; Hughes, E W; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Jedynak, M; Jiang, H; Jones, P G; Judd, E G; Kabana, S; Kang, K; Kaplan, M; Kechechyan, A; Khodyrev, V Yu; Kim, B C; Kiryluk, J; Kisiel, A; Kislov, E M; Klay, J; Klein, S R; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kowalik, K L; Kravtsov, P; Kravtsov, V I; Krämer, M; Krüger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kutuev, R K; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Laue, F; Lauret, J; Le Vine, M J; Lebedev, A; Lednicky, R; Lee, C H; Lehocka, S; Li, C; Li, Q; Li, Y; Lin, G; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, J; Liu, L; Liu, Q J; Liu, Z; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Love, W A; Lu, Y; Ludlam, T; Lynn, D; López-Noriega, M; Ma, G L; Ma, J G; Ma, Y G; Magestro, D; Mahajan, S; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J N; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Meissner, F; Melnik, Yu M; Meschanin, A; Miller, M L; Minaev, N G; Mironov, C; Mischke, A; Mishra, D K; Mitchell, J; Mohanty, B; Molnár, L; Moore, C F; Morozov, D A; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Netrakanti, P K; Nikitin, V A; Nogach, L V; Nurushev, S B; Odyniec, Grazyna Janina; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Pal, S K; Panebratsev, Yu A; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevozchikov, V; Perkins, C; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M V; Potrebenikova, E V; Potukuchi, B V K S; Prindle, D; Pruneau, C A; Putschke, J; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D M; Reid, J G; Reinnarth, J; Renault, G; Retière, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M J; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Sarsour, M; Savin, I; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Schweda, K; Seger, J; Selyuzhenkov, I; Sen-Gupta, A; Seyboth, P; Shahaliev, E; Shao, M; Shao, W; Sharma, M; Shen, W Q; Shestermanov, K E; Shimansky, S S; Sichtermann, E P; Simon, F; Singaraju, R N; Smirnov, N; Snellings, R; Sood, G; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Stock, R; Stolpovsky, A; Strikhanov, M N; Stringfellow, B C; Suaide, A A P; Sugarbaker, E R; Sumbera, M; Surrow, B; Swanger, M; Symons, T J M; Szanto de Toledo, A; Sørensen, P; Tai, A; Takahashi, J; Tang, A H; Tarnowsky, T J; Thein, D; Thomas, J H; Timmins, A R; Timoshenko, S; Tokarev, M; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; Van Leeuwen, M; Van der Kolk, N; Van der Molen, A M; Varma, R; Vasilev, A N; Vasilevski, I M; Vernet, R; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Waggoner, W T; Wang, F; Wang, G; Wang, X L; Wang, Y; Wang, Z M; Ward, H; Watson, J W; Webb, J C; Westfall, G D; Wetzler, A; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yamamoto, E; Yepes, P; Yoo, I K; Yurevich, V I; Zborovský, I; Zhang, H; Zhang, W M; Zhang, Y; Zhang, Z P; Zhong, C; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N; Zuo, J X; Wang, Gang

    2006-01-01

    We present the directed flow ($v_1$) measured in Au+Au collisions at $\\sqrt{s_{_{NN}}}$ = 62 GeV in the mid-pseudorapidity region $|\\eta|<1.3$ and in the forward pseudorapidity region $2.5 < |\\eta| < 4.0$. The results are obtained using the three-particle cumulant method, the event plane method with mixed harmonics, and for the first time at the Relativistic Heavy Ion Collider (RHIC), the standard method with the event plane reconstructed from spectator neutrons. Results from all three methods are in good agreement. Over the pseudorapidity range studied, charged particle directed flow is in the direction opposite to that of fragmentation neutrons.

  13. Electrochemistry of heparin binding to tau protein on Au surfaces

    International Nuclear Information System (INIS)

    Highlights: • Anionic heparin binds tau protein film on Au • N-terminal of tau protein is critical for heparin binding • Negatively charged heparin binds positively charged tau domains • Heparin binding to tau increases charge transfer resistance - ABSTRACT: The tau protein is a neurodegenerative disease biomarker. The in vitro aggregation of tau is triggered by electrostatic charge imbalance induced by an anionic inducing agent, such as heparin. The binding of the tau-heparin complex is based on electrostatic interactions, but the exact binding mode of heparin to the tau protein has not been fully identified. In this work, the effects of the tau protein orientation on gold (Au) electrode to heparin were explored by the cyclic voltammetry and electrochemical impedance spectroscopy. To modulate the accessibility of N-terminal of the tau to heparin, the tau films on Au surfaces were fabricated in two ways: immobilization of tau via the N-terminal of tau protein (N-tau-Au) or by the Cys291/Cys322 residues, located in the R-repeat domains of the tau protein (Cys-tau-Au). The sulfur-Au bonding was characterized by X-ray photoelectron spectroscopy. The charge transfer resistance was measured for N-tau-Au and Cys-tau-Au as a function of heparin concentration. The heparin concentration range was varied from 0.2 pM to 216 μM with the optimal binding concentration at 21 nM (the highest charge transfer resistance value). The heparin binding to tau films was investigated in the presence of [Fe(CN)6]3−/4− or benzoquinone redox probes. The tau-heparin binding was greater for the Cys-tau-Au surface over N-tau-Au, indicating specific tau domains may be required for optimal heparin binding

  14. Tunneling characteristics of Au-alkanedithiol-Au junctions formed via nanotransfer printing (nTP).

    Science.gov (United States)

    Niskala, Jeremy R; Rice, William C; Bruce, Robert C; Merkel, Timothy J; Tsui, Frank; You, Wei

    2012-07-25

    Construction of permanent metal-molecule-metal (MMM) junctions, though technically challenging, is desirable for both fundamental investigations and applications of molecule-based electronics. In this study, we employed the nanotransfer printing (nTP) technique using perfluoropolyether (PFPE) stamps to print Au thin films onto self-assembled monolayers (SAMs) of alkanedithiol formed on Au thin films. We show that the resulting MMM junctions form permanent and symmetrical tunnel junctions, without the need for an additional protection layer between the top metal electrode and the molecular layer. This type of junction makes it possible for direct investigations into the electrical properties of the molecules and the metal-molecule interfaces. Dependence of transport properties on the length of the alkane molecules and the area of the printed Au electrodes has been examined systematically. From the analysis of the current-voltage (I-V) curves using the Simmons model, the height of tunneling barrier associated with the molecule (alkane) has been determined to be 3.5 ± 0.2 eV, while the analysis yielded an upper bound of 2.4 eV for the counterpart at the interface (thiol). The former is consistent with the theoretical value of ~3.5-5.0 eV. The measured I-V curves show scaling with respect to the printed Au electrode area with lateral dimensions ranging from 80 nm to 7 μm. These results demonstrate that PFPE-assisted nTP is a promising technique for producing potentially scalable and permanent MMM junctions. They also demonstrate that MMM structures (produced by the unique PFPE-assisted nTP) constitute a reliable test bed for exploring molecule-based electronics. PMID:22720785

  15. Autopistas: AU-1 25 de Mayo y AU-6 Perito Moreno

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1981-02-01

    Full Text Available Highways AU-1 and AU-6, approximately 17 km. long, were constructed for the purpose of solving the serious traffic problems in Buenos Aires, a city of nine million inhabitants and an evergrowing number of cars. A computer program was created for the design based on the geometric shape of the highway and the position of the supports. Using this, all elements composing the structure were calculated and the framework was sized. This programme made it possible to complete a stretch of 150 metres per week. The very rapid construction was carried out through self-supporting arches made of metallic beams held in place by brackets. The brackets were fitted in specially designed grooves in the major supports of the highway.

    Las autopistas AU-1 y AU-6, con una longitud aproximada de 17 km, se realizaron con objeto de resolver el grave problema de infraestructura vial del Municipio de Buenos Aires, ciudad de nueve millones de habitantes y con un parque de vehículos en rápido crecimiento. Para el proyecto se creó un programa de ordenador con el que, partiendo de la definición geométrica de la autopista y de la posición de las pilas, se calculan todos los elementos que componen la estructura y se dimensionan las armaduras. Este programa permitió proyectar un tramo (150 m por semana. La construcción, a un ritmo muy rápido, se llevó a cabo mediante cimbras autoportantes compuestas por vigas metálicas apoyadas sobre ménsulas, las cuales a su vez apoyan en unos nichos dejados en las pilas.

  16. Gold surfaces and nanoparticles are protected by Au(0)-thiyl species and are destroyed when Au(I)-thiolates form

    DEFF Research Database (Denmark)

    Reimers, Jeffrey R.; Ford, Michael J.; Halder, Arnab; Ulstrup, Jens; Hush, Noel S.

    2016-01-01

    the noble character of gold and nanoparticle surfaces that destabilizes Au(I)-thiolates. Bonding results from large van der Waals forces, influenced by covalent bonding induced through s-d hybridization and charge polarization effects that perturbatively mix in some Au(I)-thiolate character. A simple...

  17. Charged particle multiplicity fluctuations in Au+Au collisions at \\sqrt{s_{NN}} = 200\\, {\\rm GeV}

    Science.gov (United States)

    Wozniak, Krzysztof; PHOBOS Collaboration; Back, B. 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.; Decowski, M. P.; García, E.; 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, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; 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.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J. L.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L. H.; Wosiek, B.; Wuosmaa, A. H.; Wyslouch, B.

    2004-08-01

    This paper presents the first PHOBOS results on charged particle multiplicity fluctuations measured for Au+Au collisions at the highest RHIC energy within a wide pseudorapidity range of |eegr| < 3. The dependence on collision geometry is removed in the analysis by using the normalized difference between the number of particles in separate eegr bins. We compare our data to HIJING model predictions.

  18. Inclusive cross section and correlations of fully reconstructed jets in 200 GEV Au+Au and p+p collisions

    OpenAIRE

    Ploskon, Mateusz; Collaboration, for the STAR

    2009-01-01

    We present an experimental study of full jet reconstruction in the high multiplicity environment of heavy ion collisions, utilizing 200 GeV p+p and central Au+Au data measured by STAR. Inclusive differential jet production cross sections and ratios are reported, as well as high-pT hadron-jet coincidences.

  19. Electronic and resonance Raman spectra of [Au2(CS3)2]2-. Spectroscopic properties of a "short" Au(I)-Au(I) bond.

    Science.gov (United States)

    Cheng, E C; Leung, K H; Miskowski, V M; Yam, V W; Phillips, D L

    The anion [Au2(CS3)2]2- has an unusually short Au-Au distance (2.80 A) for a binuclear Au(I) complex. We report detailed Raman studies of the nBu4N+ salt of this complex, including FT-Raman of the solid and UV/vis resonance Raman of dimethyl sulfoxide solutions. All five totally symmetric vibrations of the anion have been located and assigned. A band at delta nu = 125 cm-1 is assigned to nu (Au2). The visible-region electronic absorption bands (384 (epsilon 30,680) and 472 nm (epsilon 610 M-1 cm-1)) are attributable to CS3(2-) localized transitions, as confirmed by the dominance of nu sym(C-Sexo) (delta nu = 951 cm-1) in RR spectra measured in this region. An absorption band at 314 nm (22,250 M-1 cm-1) is assigned as the metal-metal 1(d sigma*-->p sigma) transition, largely because nu sym(C-Sexo) is not strongly enhanced in RR involving this band. Observation of the expected strong resonance enhancement of nu (Au2) was precluded as a result of masking by intense solvent Rayleigh scattering in the UV. PMID:11196834

  20. 超声楔键合Au/Al和Al/Au界面IMC演化%Intermetallic Compound Evolution of Ultrasonic Au/Al and Al/Au Wedge Bond

    Institute of Scientific and Technical Information of China (English)

    计红军; 李明雨; 王春青

    2007-01-01

    基于固体相变理论,研究Au丝、Al丝超声楔-楔键合接头的温度长期可靠性.200℃下,存储时间<48 h时,Au/Al接头界面并未发生明显变化;随着接头存储时间增加,界面金属间化合物(IMC)开始由焊盘向引线方向生长(垂直生长);240 h时,Al焊盘完全被消耗,接头连接界面部位生成Au5Al2,周边为Au2Al;继续增加存储时间,IMC向接头水平方向生长(水平生长),Au5Al2向更稳定的Au2Al转变,IMC与引线之间形成严重的Kirkendall孔洞.Al/Au系统相对稳定得多,界面IMC生长缓慢,然而,界面化合物AuAl2导致接头裂纹,而引线内部出现严重的空洞.对比并分析了两种楔焊系统界面演变特点和产生机制.

  1. Effect of Au nano-particle aggregation on the deactivation of the AuCl3/AC catalyst for acetylene hydrochlorination

    OpenAIRE

    Bin Dai; Qinqin Wang; Feng Yu; Mingyuan Zhu

    2015-01-01

    A detailed study of the valence state and distribution of the AuCl3/AC catalyst during the acetylene hydrochlorination deactivation process is described and discussed. Temperature-programmed reduction and X-ray photoelectron spectral analysis indicate that the active Au3+ reduction to metallic Au0 is one reason for the deactivation of AuCl3/AC catalyst. Transmission electron microscopy characterization demonstrated that the particle size of Au nano-particles increases with increasing reaction...

  2. Structure and Mobility of Metal Clusters in MOFs: Au, Pd, and AuPd Clusters in MOF-74

    DEFF Research Database (Denmark)

    Vilhelmsen, Lasse; Walton, Krista S.; Sholl, David S.

    2012-01-01

    Understanding the adsorption and mobility of metal–organic framework (MOF)-supported metal nanoclusters is critical to the development of these catalytic materials. We present the first theoretical investigation of Au-, Pd-, and AuPd-supported clusters in a MOF, namely MOF-74. We combine density...... functional theory (DFT) calculations with a genetic algorithm (GA) to reliably predict the structure of the adsorbed clusters. This approach allows comparison of hundreds of adsorbed configurations for each cluster. From the investigation of Au8, Pd8, and Au4Pd4 we find that the organic part of the MOF is......’s adsorption energy and diffusion barrier is established, confirming that Au clusters are highly mobile in the MOF-74 framework and Pd clusters are less mobile....

  3. Medium-sized Au40(SR)24 and Au52(SR)32 nanoclusters with distinct gold-kernel structures and spectroscopic features

    Science.gov (United States)

    Xu, Wen Wu; Li, Yadong; Gao, Yi; Zeng, Xiao Cheng

    2016-01-01

    We have analyzed the structures of two medium-sized thiolate-protected gold nanoparticles (RS-AuNPs) Au40(SR)24 and Au52(SR)32 and identified the distinct structural features in their Au kernels [Sci. Adv., 2015, 1, e1500425]. We find that both Au kernels of the Au40(SR)24 and Au52(SR)32 nanoclusters can be classified as interpenetrating cuboctahedra. Simulated X-ray diffraction patterns of the RS-AuNPs with the cuboctahedral kernel are collected and then compared with the X-ray diffraction patterns of the RS-AuNPs of two other prevailing Au-kernels identified from previous experiments, namely the Ino-decahedral kernel and icosahedral kernel. The distinct X-ray diffraction patterns of RS-AuNPs with the three different types of Au-kernels can be utilized as signature features for future studies of structures of RS-AuNPs. Moreover, the simulated UV/Vis absorption spectra and Kohn-Sham orbital energy-level diagrams are obtained for the Au40(SR)24 and Au52(SR)32, on the basis of time-dependent density functional theory computation. The extrapolated optical band-edges of Au40(SR)24 and Au52(SR)32 are 1.1 eV and 1.25 eV, respectively. The feature peaks in the UV/Vis absorption spectra of the two clusters can be attributed to the d --> sp electronic transition. Lastly, the catalytic activities of the Au40(SR)24 and Au52(SR)32 are examined using CO oxidation as a probe. Both medium-sized thiolate-protected gold clusters can serve as effective stand-alone nanocatalysts.We have analyzed the structures of two medium-sized thiolate-protected gold nanoparticles (RS-AuNPs) Au40(SR)24 and Au52(SR)32 and identified the distinct structural features in their Au kernels [Sci. Adv., 2015, 1, e1500425]. We find that both Au kernels of the Au40(SR)24 and Au52(SR)32 nanoclusters can be classified as interpenetrating cuboctahedra. Simulated X-ray diffraction patterns of the RS-AuNPs with the cuboctahedral kernel are collected and then compared with the X-ray diffraction patterns of the RS-Au

  4. Medium-sized Au40(SR)24 and Au52(SR)32 nanoclusters with distinct gold-kernel structures and spectroscopic features.

    Science.gov (United States)

    Xu, Wen Wu; Li, Yadong; Gao, Yi; Zeng, Xiao Cheng

    2016-01-21

    We have analyzed the structures of two medium-sized thiolate-protected gold nanoparticles (RS-AuNPs) Au40(SR)24 and Au52(SR)32 and identified the distinct structural features in their Au kernels [Sci. Adv., 2015, 1, e1500425]. We find that both Au kernels of the Au40(SR)24 and Au52(SR)32 nanoclusters can be classified as interpenetrating cuboctahedra. Simulated X-ray diffraction patterns of the RS-AuNPs with the cuboctahedral kernel are collected and then compared with the X-ray diffraction patterns of the RS-AuNPs of two other prevailing Au-kernels identified from previous experiments, namely the Ino-decahedral kernel and icosahedral kernel. The distinct X-ray diffraction patterns of RS-AuNPs with the three different types of Au-kernels can be utilized as signature features for future studies of structures of RS-AuNPs. Moreover, the simulated UV/Vis absorption spectra and Kohn-Sham orbital energy-level diagrams are obtained for the Au40(SR)24 and Au52(SR)32, on the basis of time-dependent density functional theory computation. The extrapolated optical band-edges of Au40(SR)24 and Au52(SR)32 are 1.1 eV and 1.25 eV, respectively. The feature peaks in the UV/Vis absorption spectra of the two clusters can be attributed to the d → sp electronic transition. Lastly, the catalytic activities of the Au40(SR)24 and Au52(SR)32 are examined using CO oxidation as a probe. Both medium-sized thiolate-protected gold clusters can serve as effective stand-alone nanocatalysts. PMID:26676095

  5. Theoretical studies of acrolein hydrogenation on Au20 nanoparticle

    Science.gov (United States)

    Li, Zhe; Chen, Zhao-Xu; He, Xiang; Kang, Guo-Jun

    2010-05-01

    Gold nanoparticles play a key role in catalytic processes. We investigated the kinetics of stepwise hydrogenation of acrolein on Au20 cluster model and compared with that on Au(110) surface. The rate-limiting step barrier of CC reduction is about 0.5 eV higher than that of CO hydrogenation on Au(110) surface. On Au20 nanoparticle, however, the energy barrier of the rate-determining step for CC hydrogenation turns out to be slightly lower than the value for the CO reduction. The selectivity difference on the two substrate models are attributed to different adsorption modes of acrolein: via the CC on Au20, compared to through both CC and CO on Au(110). The preference switch implies that the predicted selectivity of competitive hydrogenation depends on substrate model sensitively, and particles with more low-coordinated Au atoms than flat surfaces are favorable for CC hydrogenation, which is in agreement with experimental result.

  6. Ge-Au eutectic bonding of Ge {100} single crystals

    Science.gov (United States)

    Knowlton, W. B.; Itoh, K. M.; Beeman, J. W.; Emes, J. H.; Loretto, D.; Haller, E. E.

    1993-11-01

    We present preliminary results on the eutectic bonding between two {100} Ge single crystal surfaces using thin films of Au ranging from 900Å/surface to 300Å/surface and Pd (10% the thickness of Au). Following bonding, plan view optical microscopy (OM) of the cleaved interface of samples with Au thicknesses ≤ 500Å/surface show a eutectic morphology more conducive to phonon transmission through the bond interface. High resolution transmission electron microscopy (HRTEM) cross sectional interface studies of a 300Å/surface Au sample show epitaxial growth of Ge. In sections of the bond, lattice continuity of the Ge is apparent through the interface. TEM studies also reveal heteroepitaxial growth of Au with a Au-Ge lattice mismatch of less than 2%. Eutectic bonds with 200Å/surface Au have been attained with characterization pending. An optical polishing technique for Ge has been optimized to insure intimate contact between the Ge surfaces prior to bonding. Interferometry analysis of the optically polished Ge surface shows that surface height fluctuations lie within ±150Å across an interval of 1mm. Characterization of phonon transmission through the interface is discussed with respect to low temperature detection of ballistic phonons.

  7. Tailoring the FeRh magnetostructural response with Au diffusion

    Science.gov (United States)

    Loving, M.; de Vries, M. A.; Jimenez-Villacorta, F.; Le Graët, C.; Liu, X.; Fan, R.; Langridge, S.; Heiman, D.; Marrows, C. H.; Lewis, L. H.

    2012-08-01

    Factors which contribute to magnetostructural transition control have been demonstrated by study of the effects of Au incorporation on the magnetic and structural character of CsCl-structured equiatomic FeRh thin films. Sputtered films were capped with 2 nm of Au deposited at 873 K and at 323 K and subsequently characterized with magnetometry and synchrotron-based structural probes. Diffusion of Au into the FeRh film layer at 873 K is confirmed by a reduction in the Au capping layer thickness relative to the film capped at 323 K. The impact of Au diffusion on the FeRh magnetostructural character is noted by a decrease in the onset of the transition temperature, a thermally broadened first-order transition and an increased sensitivity of the transition to applied magnetic field. Additionally, magnetization data indicate that Au diffusion causes retention of the ferromagnetic phase well below the normal magnetostructural transition temperature. These results are attributed to a multiphase FeRh film layer created by thermally driven Au diffusion.

  8. First principles calculations of the optical and plasmonic response of Au alloys and intermetallic compounds.

    Science.gov (United States)

    Keast, V J; Barnett, R L; Cortie, M B

    2014-07-30

    Pure Au is widely used in plasmonic applications even though its use is compromised by significant losses due to damping. There are some elements that are less lossy than Au (e.g. Ag or Al) but they will normally oxidize or corrode under ambient conditions. Here we examine whether alloying Au with a second element would be beneficial for plasmonic applications. In order to evaluate potential alternatives to pure Au, the density of states (DOS), dielectric function and plasmon quality factor have been calculated for alloys and compounds of Au with Al, Cd, Mg, Pd, Pt, Sn, Ti, Zn and Zr. Substitutional alloying of Au with Al, Cd, Mg and Zn was found to slightly improve the plasmonic response. Of the large number of intermetallic compounds studied, only AuAl2, Au3Cd, AuMg, AuCd and AuZn were found to be suitable for plasmonic applications. PMID:25001413

  9. Structural, electronic and magnetic properties of Au-based monolayer derivatives in honeycomb structure

    Science.gov (United States)

    Kapoor, Pooja; Sharma, Munish; Kumar, Ashok; Ahluwalia, P. K.

    2016-05-01

    We present electronic properties of atomic layer of Au, Au2-N, Au2-O and Au2-F in graphene-like structure within the framework of density functional theory (DFT). The lattice constant of derived monolayers are found to be higher than the pristine Au monolayer. Au monolayer is metallic in nature with quantum ballistic conductance calculated as 4G0. Similarly, Au2-N and Au2-F monolayers show 4G0 and 2G0 quantum conductance respectively while semiconducting nature with calculated band gap of 0.28 eV has been observed for Au2-O monolayer. Most interestingly, half metalicity has been predicted for Au2-N and Au2-F monolayers. Our findings may have importance for the application of these monolayers in nanoelectronic and spintronics.

  10. Energy level alignment in Au/pentacene/PTCDA trilayer stacks

    Science.gov (United States)

    Sehati, P.; Braun, S.; Fahlman, M.

    2013-09-01

    Ultraviolet photoelectron spectroscopy is used to investigate the energy level alignment and molecular orientation at the interfaces in Au/pentacene/PTCDA trilayer stacks. We deduced a standing orientation for pentacene grown on Au while we conclude a flat lying geometry for PTCDA grown onto pentacene. We propose that the rough surface of polycrystalline Au induces the standing geometry in pentacene. It is further shown that in situ deposition of PTCDA on pentacene can influence the orientation of the surface pentacene layer, flipping part of the surface pentacene molecules into a flat lying geometry, maximizing the orbital interaction across the pentacene-PTCDA heterojunction.

  11. AuScope VLBI Project and Hobart 26-m Antenna

    Science.gov (United States)

    Lovell, Jim; Dickey, John; Reid, Brett; McCallum, Jamie; Shabala, Stas; Watson, Christopher; Ellingsen, Simon; Memin, Anthony

    2013-01-01

    This is a report on the activities carried out at the three AuScope VLBI observatories and the Hobart 26-m antenna. In 2012 the three AuScope 12-m antennas at Hobart (Hb), Katherine (Ke), and Yarragadee (Yg) completed their first full year of operations as an array. The Hobart 26-m antenna (Ho) continued to make a contribution to IVS, providing overlap with the Hb time series. In total the AuScope antennas and the Hobart 26 m observed for 146 antenna days in 2012. In this report we also briefly highlight our research activities during 2012 and our plans for 2013.

  12. Optical Behaviour of ZnO/Au Nanojunctions

    Directory of Open Access Journals (Sweden)

    Shital V. Kahane

    2011-01-01

    Full Text Available ZnO/Au nanojunctions were prepared by electrochemical method at room temperature. Nanojunction formation is vivid from appearance of ZnO and Au features in x-ray diffraction pattern. Optical absorption spectra reveal excitonic as well as surface plasmon resonance (SPR feature in case of nanojunctions. Bleaching of the excitonic feature associated with the blue shift, is a signature of charge transfer from Au to ZnO at the interface of nanojunction. An increase in intensity of band edge luminescence and quenching of green emission indicates the passivation of surface defects due to formation of nanojunctions.

  13. Electrochemical Capacitance DNA Sensing at Hairpin-Modified Au Electrodes

    OpenAIRE

    Joel Rivera-Gandía; Maria del Mar Maldonado; Yarimar De La Torre-Meléndez; Edwin O. Ortiz-Quiles; Vargas-Barbosa, Nella M.; Cabrera, Carlos R.

    2011-01-01

    An interfacial capacitance measurement electrochemical technique has been used for the sensing of self-assembled DNA hairpin probes (M. tuberculosis and B. anthracis) attached to Au electrodes. The double-layer capacitance (Cdl) was determined with electrochemical perturbations from 0.2 V to 0.5 V versus Ag/AgCl at a Au/M. tuberculosis DNA hairpin probe at surface coverage Au electrodes. The capacitance study was done at pH 7, which was necessary to maintain the M. tuberculosis and B. anthrac...

  14. Thermodynamic description of Au-Ag-Si ternary system

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on the available experimental information, the Ag-Si binary system was thermodynamically assessed using the CALPHAD method. The solution phases, including liquid, fcc-Al and diamond-A4, were modeled as substitutional solutions, of which the excess Gibbs energies were expressed by Redlich-Kister polynomial functions. Combined with previous assessment of the Ag-Au and Au-Si binary systems, thermodynamic description of the Au-Ag-Si ternary system was performed to reproduce the reported phase equilibria. Thermodynamic properties of liquid alloys, liquidus projection and several vertical and isothermal sections of this ternary system were calculated, which are in reasonable agreement with the reported experimental data.

  15. d+Au Hadron Correlation Measurements from PHENIX

    OpenAIRE

    Sickles, Anne M.; Collaboration, for the PHENIX

    2013-01-01

    Recent observations of extended pseudorapidity correlations at the LHC in p+p and p+Pb collisions are of great interest. Here we present related re- sults from d+Au collisions at PHENIX. We present the observed v2 and discuss the possible origin in the geometry of the collision region. We also present new measurements of the pseudorapidity dependence of the ridge in d+Au collision. Future plans to clarify the role of geometry in small collision systems using 3He+Au collisions are discussed.

  16. Au(111) and Pt(111) surface phase behavior

    DEFF Research Database (Denmark)

    Sandy, A.R.; Mochrie, S.G.J.; Zehner, D.M.;

    1993-01-01

    We describe our recent X-ray scattering studies of the structure and phases of the clean Au(111) and Pt(111) surfaces. Below 0.65 of their respective bulk melting temperatures, the Au(111) surface has a well-ordered chevron reconstruction and the Pt(111) surface is unreconstructed. Above these...... temperatures, both surfaces reconstruct to form layers that are isotropically compresses and have only short-range order. Throughout their reconstructed phases, the densities of the Au and Pt(111) surfaces increase with increasing temperature....

  17. Controlling Au Photodeposition on Large ZnO Nanoparticles.

    Science.gov (United States)

    Fernando, Joseph F S; Shortell, Matthew P; Noble, Christopher J; Harmer, Jeffrey R; Jaatinen, Esa A; Waclawik, Eric R

    2016-06-01

    This study investigated how to control the rate of photoreduction of metastable AuCl2(-) at the solid-solution interface of large ZnO nanoparticles (NPs) (50-100 nm size). Band-gap photoexcitation of electronic charge in ZnO by 370 nm UV light yielded Au NP deposition and the formation of ZnO-Au NP hybrids. Au NP growth was observed to be nonepitaxial, and the patterns of Au photodeposition onto ZnO NPs observed by high-resolution transmission electron microscopy were consistent with reduction of AuCl2(-) at ZnO facet edges and corner sites. Au NP photodeposition was effective in the presence of labile oleylamine ligands attached to the ZnO surface; however, when a strong-binding dodecanethiol ligand coated the surface, photodeposition was quenched. Rates of interfacial electron transfer at the ZnO-solution interface were adjusted by changing the solvent, and these rates were observed to strongly depend on the solvent's permittivity (ε) and viscosity. From measurements of electron transfer from ZnO to the organic dye toluidine blue at the ZnO-solution interface, it was confirmed that low ε solvent mixtures (ε ≈ 9.5) possessed markedly higher rates of photocatalytic interfacial electron transfer (∼3.2 × 10(4) electrons·particle(-1)·s(-1)) compared to solvent mixtures with high ε (ε = 29.9, ∼1.9 × 10(4) electrons·particle(-1)·s(-1)). Dissolved oxygen content in the solvent and the exposure time of ZnO to band-gap, near-UV photoexcitation were also identified as factors that strongly affected Au photodeposition behavior. Production of Au clusters was favored under conditions that caused electron accumulation in the ZnO-Au NP hybrid. Under conditions where electron discharge was rapid (such as in low ε solvents), AuCl2(-) precursor ions photoreduced at ZnO surfaces in less than 5 s, leading to deposition of several small, isolated ∼6 nm Au NP on the ZnO host instead. PMID:27196721

  18. 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.

  19. A simple approach for facile synthesis of Ag, anisotropic Au and bimetallic (Ag/Au) nanoparticles using cruciferous vegetable extracts

    International Nuclear Information System (INIS)

    We present a simple and straightforward approach for the synthesis and stabilization of relatively monodisperse Ag, Au and bimetallic (Ag/Au) nanoparticles by using cruciferous vegetable (green/red) extracts by simply adjusting the pH environment in the aqueous medium. The vegetable extracts act both as reducing and capping agents. The monometallic and bimetallic nanoparticles of Ag and Au so obtained were characterized by UV–visible spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM). It is shown that red cabbage extract can be used for the preparation of anisotropic Au nanoparticles. The formation of Au anisotropic nanoparticles was found to depend on a number of environmental factors, such as the pH of the reaction medium, reaction time, and initial reactant concentrations. Additionally, it is shown that these extract-stabilized Au and Ag nanoparticles can be used as a seed for preparation of bimetallic Au/Ag nanoparticles. For bimetallic alloy nanoparticles the absorption peak was observed between the two maxima of the corresponding metallic particles. The surface plasmon absorption maxima for bimetallic nanoparticles changed linearly with increasing Au mole ratio content in various alloy compositions. It has been shown that the formation of hollow Au spheres depends on the experimental conditions. - Graphical abstract: TEM image of gold nanoparticles at pH 3.27 formed by red cabbage extract. Highlights: ► First report on the reactivity of the extracts toward metal ions using a spectrophotometric technique. ► Red cabbage extract has better reducing properties than green cabbage extract. ► Red cabbage extract can reduce metal ions at any pH. ► Reduction of metal ions can have important consequences in the study of soil chemistry.

  20. A simple approach for facile synthesis of Ag, anisotropic Au and bimetallic (Ag/Au) nanoparticles using cruciferous vegetable extracts

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, Jasmine; Mukherjee, Tulsi; Kapoor, Sudhir, E-mail: sudhirk@barc.gov.in

    2012-10-01

    We present a simple and straightforward approach for the synthesis and stabilization of relatively monodisperse Ag, Au and bimetallic (Ag/Au) nanoparticles by using cruciferous vegetable (green/red) extracts by simply adjusting the pH environment in the aqueous medium. The vegetable extracts act both as reducing and capping agents. The monometallic and bimetallic nanoparticles of Ag and Au so obtained were characterized by UV-visible spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM). It is shown that red cabbage extract can be used for the preparation of anisotropic Au nanoparticles. The formation of Au anisotropic nanoparticles was found to depend on a number of environmental factors, such as the pH of the reaction medium, reaction time, and initial reactant concentrations. Additionally, it is shown that these extract-stabilized Au and Ag nanoparticles can be used as a seed for preparation of bimetallic Au/Ag nanoparticles. For bimetallic alloy nanoparticles the absorption peak was observed between the two maxima of the corresponding metallic particles. The surface plasmon absorption maxima for bimetallic nanoparticles changed linearly with increasing Au mole ratio content in various alloy compositions. It has been shown that the formation of hollow Au spheres depends on the experimental conditions. - Graphical abstract: TEM image of gold nanoparticles at pH 3.27 formed by red cabbage extract. Highlights: Black-Right-Pointing-Pointer First report on the reactivity of the extracts toward metal ions using a spectrophotometric technique. Black-Right-Pointing-Pointer Red cabbage extract has better reducing properties than green cabbage extract. Black-Right-Pointing-Pointer Red cabbage extract can reduce metal ions at any pH. Black-Right-Pointing-Pointer Reduction of metal ions can have important consequences in the study of soil chemistry.

  1. De l’individu postcommuniste au citoyen

    Directory of Open Access Journals (Sweden)

    Anna Krasteva

    2009-11-01

    Full Text Available L’article analyse le paradoxe de la conception communiste du citoyen engagé : au niveau idéologique, citoyenneté et engagement sont intrinsèquement liés, au niveau politique ils sont souvent radicalement dissociés. Le citoyen communiste est plus engagé que citoyen. La citoyenneté était dépourvue de plusieurs de ses attributs : de la jouissance de la loi qui établit « l’égalité arithmétique » et minorise les maîtres ; de la citoyenneté active – civile et politique – pour ne jouir que la protection sociale ; de la participation au profit de l’appartenance. L’individu communiste était engagé, non pas parce qu’il l’avait choisi dans la liberté, mais parce qu’il n’avait pas la liberté de se désengager. L’article compare l’engagement communiste et postcommuniste en analysant le second au croisement de l’individualité et de la citoyenneté et en distinguant trois formes de désengagement – contestataire, « bonapartiste » et individualiste et trois formes d’engagement – mimétique, héroïque, civique.From the postcommunist individual to the citizenThe article analysis the paradox of the communist conception of the engaged citizen: at ideological level, citizenship and participation are closely linked; at political level, they are radically dissociated. The communist citizen is more engaged than citizen. The citizenship is deprived of several of its attributes: of the law which establishes "the arithmetic equality" and minimises the masters; of the active citizenship, civic and political, enjoying just the social one; of the participation for emphasizing on the belonging. The communist individual is engaged not because he has chosen freely to be such, but because he had not the freedom to disengage him/herself. The article compares the communist and the post communist participation analysing the latter at the intersection of individuality and citizenship and distinguishing three forms

  2. Metanephrine neuroendocrine tumor marker detection by SERS using Au nanoparticle/Au film sandwich architecture.

    Science.gov (United States)

    Boca, Sanda; Farcau, Cosmin; Baia, Monica; Astilean, Simion

    2016-02-01

    Neuroendocrine tumors, such as pheochromocytoma or paraganglioma, are dangerous tumors that constitute a potential threat for a large number of patients. Currently, the biochemical diagnosis of neuroendocrine tumors is based on measurement of the direct secretory products of the adrenomedullary-sympathetic system or of their metabolites, such as catecholamines or their metanephrine derivatives, from plasma or urine. The techniques used for analysis of plasma free metanephrines, i.e. high-performance liquid chromatography or high-performance liquid chromatography coupled with mass-spectrometry are technically-demanding and time consuming, which limit their availability. Here we demonstrate a simple, fast and low-cost method for detecting metanephrine by Surface Enhanced Raman Scattering (SERS). The protocol consists in using evaporation-induced self-assembly of gold (Au) nanoparticles incubated with the analyte, on planar gold films. The assembly process produces regions with a dense distribution of both inter-particle gaps and particle-film gaps. Finite-difference time-domain simulations confirm that both kinds of gaps are locations of enhanced electromagnetic fields resulting from inter-particle and particle-film plasmonic coupling, useful for SERS amplification. Metanephrine vibrational bands assignment was performed according to density functional theory calculations. Metanephrine metabolite was detected in liquid at concentration levels lower than previously reported for other similar metabolites. The obtained results demonstrate that the Au nanoparticle/Au film exhibits noticeable SERS amplification of the adsorbed metabolite and can be used in the design of efficient, stable SERS-active substrates for the detection and identification of specific tumor markers. PMID:26820563

  3. Distributions of Charged Hadrons Associated with High Transverse Momentum Particles in pp and Au+Au Collisions at sqrt(s_NN)=200 GeV

    CERN Document Server

    Adams, J; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Arkhipkin, D; Averichev, G S; Badyal, S K; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bezverkhny, B I; Bhardwaj, S; Bhati, A K; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca-Sanchez, M; Carroll, J; Castillo, J; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; Derevshchikov, A A; Didenko, L; Dietel, T; Dong, W J; Dong, X; Draper, J E; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta-Majumdar, M R; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Faine, V; Faivre, J; Fatemi, R; Filimonov, K; Filip, P; Finch, E; Fisyak, Yu; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Gagunashvili, N; Gans, J; Ganti, M S; Gaudichet, L; Geurts, F J M; Ghazikhanian, V; Ghosh, P; González, J E; Grachov, O; Grebenyuk, O; Gronstal, S; Grosnick, D P; Guertin, S M; Sen-Gupta, A; Gutíerrez, T D; Hallman, T J; Hamed, A; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Huang Sheng Li; Hughes, E; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Janik, M; Jiang, H; Johnson, I; Jones, P G; Judd, E G; Kabana, S; Kaplan, M; Keane, D; Khodyrev, V Yu; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kovalenko, A D; Krämer, M; Kravtsov, P; Kravtsov, V I; Krüger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunde, G J; Kunz, C L; Kutuev, R K; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Le Vine, M J; Li, C; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; López-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Ma, Y G; Magestro, D; Mahajan, S; Mangotra, L K; Mahapatra, D P; Majka, R; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Meissner, F; Melnik, Yu M; Meschanin, A; Miller, M L; Milosevich, Z; Minaev, N G; Mironov, C; Mischke, A; Mishra, D; Mitchell, J; Mohanty, B; Molnár, L; Moore, C F; Mora-Corral, M J; Morozov, D A; Morozov, V; De Moura, M M; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Netrakanti, P K; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, Grazyna Janina; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pal, S K; Panebratsev, Yu A; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevozchikov, V; Perkins, C; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M V; Potrebenikova, E V; Potukuchi, B V K S; Prindle, D; Pruneau, C A; Putschke, J; Rai, G; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D M; Reid, J G; Renault, G; Retière, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L J; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schröder, L S; Schweda, K; Seger, J; Seyboth, P; Shahaliev, E; Shao, M; Shao, W; Sharma, M; Shestermanov, K E; Shimansky, S S; Singaraju, R N; Simon, F; Skoro, G P; Smirnov, N; Snellings, R; Sood, G; Sørensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stock, R; Stolpovsky, A; Strikhanov, M N; Stringfellow, B C; Struck, C; Suaide, A A P; Sugarbaker, E R; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thein, D; Thomas, J H; Timoshenko, S; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; Van der Molen, A M; Varma, R; Vasilevski, I; Vasilev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Voloshin, S A; Vznuzdaev, M; Waggoner, W; Wang, F; Wang, G; Wang, X L; Wang, Y; Wang, Z M; Ward, H; Watson, J W; Webb, J C; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yamamoto, E; Yepes, P; Yurevich, V I; Yuting, B; Zanevsky, Yu V; Zhang, H; Zhang, W M; Zhang, Z P; Zhaomin, P; Zizong, Z P; Zolnierczuk, P A; Zoulkarneev, R; Zoulkarneeva, J; Zubarev, A N

    2005-01-01

    Charged hadrons in 0.15 4 GeV/c are reconstructed in pp and Au+Au collisions at sqrt(s_NN)=200 GeV. The associated multiplicity and pt magnitude sum are found to increase from pp to central Au+Au collisions. The associated pt distributions, while similar in shape on the near side, are significantly softened on the away side in central Au+Au relative to pp and not much harder than that of inclusive hadrons. The results, consistent with jet quenching, suggest that the away-side fragments approach equilibration with the medium traversed.

  4. Shadowing effects on the nuclear suppression factor, RdAu, in d+Au interactions

    International Nuclear Information System (INIS)

    We explore how nuclear modifications to the nucleon parton distributions affect production of high transverse momentum hadrons in deuteron-nucleus collisions. We calculate the charged hadron spectra to leading order using standard fragmentation functions and shadowing parameterizations. We obtain the d+Au to pp ratio both in minimum bias collisions and as a function of centrality. The minimum bias results agree reasonably well with the BRAHMS data while the calculated centrality dependence underestimates the data and is a stronger function of pT than the data indicate

  5. Comparison of the space-time extent of the emission source in $d$$+$Au and Au$+$Au 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; Aramaki, Y; Asano, H; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Baksay, G; Baksay, L; Bandara, N S; Bannier, B; Barish, K N; Bassalleck, B; Basye, A T; Bathe, 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; Bok, J; Bok, J S; Boyle, K; Brooks, M L; Bryslawskyj, J; Buesching, H; Bumazhnov, V; Bunce, G; Butsyk, S; Camacho, C M; Campbell, S; Caringi, A; Chen, C -H; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choudhury, R K; Christiansen, P; Chujo, T; Chung, P; Chvala, O; Cianciolo, V; Citron, Z; Cole, B A; 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; DeBlasio, K; Dehmelt, K; Denisov, A; 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; Durham, J M; Durum, A; Dutta, D; D'Orazio, L; Edwards, S; Efremenko, Y V; Ellinghaus, F; Engelmore, T; Enokizono, A; En'yo, H; Esumi, S; 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; Gal, C; Gallus, P; Garg, P; Garishvili, I; Ge, H; Giordano, F; Glenn, A; Gong, H; Gonin, M; 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; Haggerty, J S; Hahn, K I; Hamagaki, H; Hamblen, J; Han, R; Han, S Y; Hanks, J; Hartouni, E P; Hasegawa, S; Haslum, E; Hayano, R; He, X; Heffner, M; Hemmick, T K; Hester, T; Hill, J C; Hohlmann, M; Hollis, R S; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hornback, D; Hoshino, T; Huang, J; Huang, S; Ichihara, T; Ichimiya, R; Ide, J; Ikeda, Y; Imai, K; Imazu, Y; Inaba, M; Iordanova, A; Isenhower, D; 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; Johnson, B M; Jones, T; Joo, E; Joo, K S; Jouan, D; Jumper, D S; Kajihara, F; Kametani, S; Kamihara, N; Kamin, J; Kang, J H; Kang, J S; 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, S H; Kim, Y -J; Kim, Y K; Kinney, E; Kiriluk, K; Kiss, Á; Kistenev, E; Klatsky, J; Kleinjan, D; Kline, P; Koblesky, T; Kochenda, L; Kofarago, M; Komkov, B; Konno, M; Koster, J; Kotchetkov, D; Kotov, D; Kozlov, A; Král, A; Kravitz, A; 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, J; Lee, K; Lee, K B; Lee, K S; Lee, S H; Leitch, M J; Leite, M A L; Leitgab, M; Leitner, E; 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; Luechtenborg, R; Lynch, D; Maguire, C F; Makdisi, Y I; Makek, M; Malakhov, A; Malik, M D; Manion, A; Manko, V I; Mannel, E; Mao, Y; 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; Milov, A; Mishra, D K; Mishra, M; Mitchell, J T; Miyasaka, S; Mizuno, S; Mohanty, A K; Montuenga, P; Moon, H J; Moon, T; Morino, Y; Morreale, A; Morrison, D P; Moukhanova, T V; Murakami, T; Murata, J; Mwai, A; Nagamiya, S; 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; Nouicer, R; Novitzky, N; Nyanin, A S; Oakley, C; O'Brien, E; Oda, S X; Ogilvie, C A; Oka, M; Okada, K; Onuki, Y; Koop, J D Orjuela; Oskarsson, A; Ouchida, M; Ozaki, H; Ozawa, K; Pak, R; 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; Reygers, K; Reynolds, D; Riabov, V; Riabov, Y; Richardson, E; Riveli, N; Roach, D; Roche, G; Rolnick, S D; Rosati, M; Rosen, C A; Rosendahl, S S E; Rosnet, P; Rowan, Z; Rubin, J G; Rukoyatkin, P; Ružička, P; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakashita, K; 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, A Yu; Sen, A

    2014-01-01

    Two-pion interferometry measurements in $d$$+$Au and Au$+$Au collisions at $\\sqrt{s_{{NN}}}=200$ GeV are used to extract and compare the Gaussian source radii R$_{{\\rm out}}$, R$_{{\\rm side}}$, and R$_{{\\rm long}}$, which characterize the space-time extent of the emission sources. The comparisons, which are performed as a function of collision centrality and the mean transverse momentum for pion pairs, indicate strikingly similar patterns for the $d$$+$Au and Au$+$Au systems. They also indicate a linear dependence of R$_{{\\rm side}}$ on the initial transverse geometric size $\\bar{R}$, as well as a smaller freeze-out size for the $d$$+$Au system. These patterns point to the important role of final-state rescattering effects in the reaction dynamics of $d$$+$Au collisions.

  6. Les immigrants dans les regions metropolitaines de recensement au Canada

    OpenAIRE

    Schellenberg, Grant

    2004-01-01

    Dans ce rapport, on examine les facteurs des immigrants dans les regions metropolitaines de recensement (RMR) au Canada, les repercussions sur les services publics offerts dans les regions urbaines et les caracteristiques de l'emploi des immigrants.

  7. EST Table: AU004617 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available AU004617 ws20666 10/09/28 54 %/178 aa ref|XP_002430772.1| tyrosine-protein phosphatase corkscrew..., putative [Pediculus humanus corporis] gb|EEB18034.1| tyrosine-protein phosphatase corkscrew,

  8. Ordered Au Nanodisk and Nanohole Arrays: Fabrication and Applications

    KAUST Repository

    Zheng, Yue Bing

    2010-01-01

    We have utilized nanosphere lithography (NSL) to fabricate ordered Au nanodisk and nanohole arrays on substrates and have studied the localized surface plasmon resonance (LSPR) of the arrays. Through these investigations, we demonstrate that the angle- dependent behavior of the LSPR in the Au nanodisk arrays enables real-time observation of exciton-plasmon couplings. In addition, we show that the NSL-fabricated Au nanohole arrays can be applied as templates for patterning micro-/nanoparticles under capillary force. The unique structural and plasmonic characteristics of the Au nanodisk and nano- hole arrays, as well as the low-cost and high-throughput NSL-based nanofabrication technique, render these arrays excellent platforms for numerous engineering applications. © 2010 by ASME.

  9. Dynamic features of rod-shaped Au nanoclusters

    Science.gov (United States)

    So, Woong Young; Das, Anindita; Wang, Shuxin; Zhao, Shuo; Byun, Hee Young; Lee, Dana; Kumar, Santosh; Jin, Rongchao; Peteanu, Linda A.

    2015-08-01

    Gold nanoclusters hold many potential applications such as biosensing and optics due to their emission characteristics, small size, and non-toxicity. However, their low quantum yields remain problematic for further applications, and their fluorescence mechanism is still unclear. To increase the low quantum yields, various methods have been performed: doping, tuning structures, and changing number of gold atoms. In the past, most characterizations have been performed on spherical shaped nanoclusters; in this paper, several characterizations of various rod-shaped Au nanoclusters specifically on Au25 are shown. It has been determined that the central gold atom in Au25 nano-rod is crucial in fluorescence. Furthermore, single molecule analysis of silver doped Au25 nano-rod revealed that it has more photo-stability than conjugated polymers and quantum dots.

  10. Assembling Bare Au Nanoparticles at Positively Charged Templates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenjie; Zhang, Honghu; Kuzmenko, Ivan; Mallapragada, Surya; Vaknin, David

    2016-05-26

    In-situ X-ray reflectivity (XRR) and grazing incidence X-ray small-angle scattering (GISAXS) reveal that unfunctionalized (bare) gold nanoparticles (AuNP) spontaneously adsorb to a cationic lipid template formed by a Langmuir monolayer of DPTAP (1,2-dihexadecanoyl-3-trimethylammonium-propane) at vapor/aqueous interfaces. Analysis of the XRR yields the electron density profile across the chargedinterfaces along the surface normal showing the AuNPs assemble with vertical thickness comparable to the particle size. The GISAXS analysis indicates that the adsorbed mono-particle layer exhibits shortrange in-plane correlations. By contrast, single-stranded DNA-functionalized AuNPs, while attracted to the positively charged surface (more efficiently with the addition of salt to the solution), display less in-plane regular packing compared to bare AuNPs.

  11. Cent ans d'aller au cinéma

    OpenAIRE

    Arnaud, Pierre,; Augier, Agnès; Augros, Joël; Berthomé, Jean-Pierre; Bertrand, Claude-Jean; Bordat, Francis; Bosséno, Christian-Marc; Dean, John; Etcheverry, Michel; Frey, Nicole Vigouroux; Gomery, Douglas; Masson, Alain; Muraire, André

    2013-01-01

    Aux Etats-Unis plus manifestement encore qu’en Europe, « aller au cinéma » a recouvert des réalités extraordinairement diverses. « Aller au cinéma », en 1902, dans un Hale’s Tours and Scenes of the World n’a rien à voir avec « aller au cinéma » dans un nickelodeon de 1908 ou dans un picture palace de 1925. « Aller au cinéma » dans les années de la Dépression, quand se généralisent les doubles programmes, les primes de fidélité et les loteries, et quand les chômeurs viennent dormir, sinon rêve...

  12. Prolonged reorganization of thiol-capped Au nanoparticles layered structures

    Directory of Open Access Journals (Sweden)

    Sarathi Kundu

    2013-09-01

    Full Text Available Prolonged reorganization behaviour of mono-, di-, tri- and multi-layer films of Au nanoparticles prepared by Langmuir-Blodgett method on hydrophobic Si(001 substrates have been studied by using X-ray scattering techniques. Out-of-plane study shows that although at the initial stage the reorganization occurs through the compaction of the films keeping the layered structure unchanged but finally all layered structures modify to monolayer structure. Due to this reorganization the Au density increases within the nanometer thick films. In-plane study shows that inside the reorganized films Au nanoparticles are distributed randomly and the particle size modifies as the metallic core of Au nanoparticles coalesces.

  13. Electrochemical Tuning of the Dielectric Function of Au Nanoparticles

    OpenAIRE

    Brown, Ana M.; Sheldon, Matthew T.; Atwater, Harry A.

    2015-01-01

    The tunable dielectric response of Au nanoparticles under electrochemical bias can be interpreted in terms of changes in the surface charge density, surface damping, and the near-surface volume fraction of the nanoparticles that experience a modified dielectric function, as well as changes in the index of refraction of the surrounding electrolyte medium. Using experimental bias-dependent extinction measurements, we derive a potential-dependent dielectric function for Au nanoparticles that acc...

  14. Formation, Migration, and Reactivity of Au-CO Complexes on Gold Surfaces.

    Science.gov (United States)

    Wang, Jun; McEntee, Monica; Tang, Wenjie; Neurock, Matthew; Baddorf, Arthur P; Maksymovych, Petro; Yates, John T

    2016-02-10

    We report experimental as well as theoretical evidence that suggests Au-CO complex formation upon the exposure of CO to active sites (step edges and threading dislocations) on a Au(111) surface. Room-temperature scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy, transmission infrared spectroscopy, and density functional theory calculations point to Au-CO complex formation and migration. Room-temperature STM of the Au(111) surface at CO pressures in the range from 10(-8) to 10(-4) Torr (dosage up to 10(6) langmuir) indicates Au atom extraction from dislocation sites of the herringbone reconstruction, mobile Au-CO complex formation and diffusion, and Au adatom cluster formation on both elbows and step edges on the Au surface. The formation and mobility of the Au-CO complex result from the reduced Au-Au bonding at elbows and step edges leading to stronger Au-CO bonding and to the formation of a more positively charged CO (CO(δ+)) on Au. Our studies indicate that the mobile Au-CO complex is involved in the Au nanoparticle formation and reactivity, and that the positive charge on CO increases due to the stronger adsorption of CO at Au sites with lower coordination numbers. PMID:26754257

  15. Study on antibacterial activity of chemically synthesized PANI-Ag-Au nanocomposite

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • New method of synthesizing PANI-Ag-Au nanocomposite. • Surface Plasmon resonance and formation of composite at nano level were analyzed. • HR-TEM study revealed uniform distribution of nanoparticles. • PANI-Ag-Au nanocomposite exhibited good antibacterial activity. - Abstract: Pristine polyaniline (PANI), PANI-Ag, PANI-Au and PANI-Ag-Au nanocomposites have been successfully synthesized by chemical oxidative polymerization method using aniline as monomer, ammonium persulphate as oxidant and metal (Ag, Au and Ag-Au) colloids. UV-Vis analysis exhibited surface Plasmon resonances of Ag, Au, Ag-Au nanoparticles. FT-IR spectra revealed the shift in peak position of N-H stretching. X-ray diffraction (XRD) results confirm the presence of Ag, Au and Au-Ag nanoparticles. HR-TEM images show nanosizes of Ag, Au, Ag-Au and the incorporation of such nanoparticles into the PANI matrix. Pristine PANI, PANI-Ag, PANI-Au and PANI-Ag-Au nanocomposites were tested for antibacterial activity by agar well diffusion method. PANI-Ag-Au nanocomposite exhibited higher antibacterial activity against both gram-positive [Streptococcus sp. (MTCC 890), Staphylococcus sp. (MTCC 96)] and gram-negative bacteria [Escherichia coli (MTCC 1671) and Klebsiella sp. (MTCC 7407)] when compared with PANI-Ag nanocomposite, PANI-Au nanocomposite and pristine PANI. The novelty of this study is the polymer-bimetal synthesis and its antibacterial potential

  16. Study on antibacterial activity of chemically synthesized PANI-Ag-Au nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Boomi, Pandi [Department of Industrial Chemistry, School of Chemical Sciences, Alagappa University, Karaikudi 630 003, Tamil Nadu (India); Prabu, Halliah Gurumallesh, E-mail: hgprabu2010@gmail.com [Department of Industrial Chemistry, School of Chemical Sciences, Alagappa University, Karaikudi 630 003, Tamil Nadu (India); Manisankar, Paramasivam [Department of Industrial Chemistry, School of Chemical Sciences, Alagappa University, Karaikudi 630 003, Tamil Nadu (India); Ravikumar, Sundaram [Department of Oceanography and Coastal Area Studies, School of Marine Sciences, Alagappa University, Thondi Campus 623 409, Tamil Nadu (India)

    2014-05-01

    Graphical abstract: - Highlights: • New method of synthesizing PANI-Ag-Au nanocomposite. • Surface Plasmon resonance and formation of composite at nano level were analyzed. • HR-TEM study revealed uniform distribution of nanoparticles. • PANI-Ag-Au nanocomposite exhibited good antibacterial activity. - Abstract: Pristine polyaniline (PANI), PANI-Ag, PANI-Au and PANI-Ag-Au nanocomposites have been successfully synthesized by chemical oxidative polymerization method using aniline as monomer, ammonium persulphate as oxidant and metal (Ag, Au and Ag-Au) colloids. UV-Vis analysis exhibited surface Plasmon resonances of Ag, Au, Ag-Au nanoparticles. FT-IR spectra revealed the shift in peak position of N-H stretching. X-ray diffraction (XRD) results confirm the presence of Ag, Au and Au-Ag nanoparticles. HR-TEM images show nanosizes of Ag, Au, Ag-Au and the incorporation of such nanoparticles into the PANI matrix. Pristine PANI, PANI-Ag, PANI-Au and PANI-Ag-Au nanocomposites were tested for antibacterial activity by agar well diffusion method. PANI-Ag-Au nanocomposite exhibited higher antibacterial activity against both gram-positive [Streptococcus sp. (MTCC 890), Staphylococcus sp. (MTCC 96)] and gram-negative bacteria [Escherichia coli (MTCC 1671) and Klebsiella sp. (MTCC 7407)] when compared with PANI-Ag nanocomposite, PANI-Au nanocomposite and pristine PANI. The novelty of this study is the polymer-bimetal synthesis and its antibacterial potential.

  17. Catalytic reduction of 4-nitrophenol by magnetically recoverable Au nanocatalyst.

    Science.gov (United States)

    Chang, Yang-Chuang; Chen, Dong-Hwang

    2009-06-15

    A novel magnetically recoverable Au nanocatalyst was fabricated by the simple adsorption-reduction of Au(III) ions on chitosan-coated iron oxide magnetic nanocarrier. Au nanoparticles with a mean diameter of 3.14 nm were well loaded on the surface of magnetic nanocarrier because chitosan layer provided an effective driving force in the formation and stabilization of Au nanoparticles. The resultant magnetically recoverable Au nanocatalyst exhibited excellent catalytic activity to the reduction of 4-nitrophenol (4-NP) with sodium borohydride. The rate constants evaluated in terms of pseudo-first-order kinetic model increased with increasing the amount of Au nanocatalyst, decreasing the initial 4-NP concentration, and increasing the temperature. Also, the kinetic data suggested that this catalytic reaction was diffusion controlled owing to the presence of chitosan layer. In addition, catalyst reuse showed no trace of deactivation or poisoning during the catalytic and separation processes, revealing the stable nature and good catalytic ability of this nanocatalyst. PMID:19022566

  18. Competition between Hexagonal and Tetragonal Hexabromobenzene Packing on Au(111).

    Science.gov (United States)

    Huang, Han; Tan, Zhiyu; He, Yanwei; Liu, Jian; Sun, Jiatao; Zhao, Kang; Zhou, Zhenhong; Tian, Guo; Wong, Swee Liang; Wee, Andrew Thye Shen

    2016-03-22

    Low-temperature scanning tunneling microscope investigations reveal that hexabromobenzene (HBB) molecules arrange in either hexagonally closely packed (hcp) [Formula: see text] or tetragonal [Formula: see text] structure on Au(111) dependent on a small substrate temperature difference around 300 K. The underlying mechanism is investigated by density functional theory calculations, which reveal that substrate-mediated intermolecular noncovalent C-Br···Br-C attractions induce hcp HBB islands, keeping the well-known Au(111)-22×√3 reconstruction intact. Upon deposition at 330 K, HBB molecules trap freely diffusing Au adatoms to form tetragonal islands. This enhances the attraction between HBB and Au(111) but partially reduces the intermolecular C-Br···Br-C attractions, altering the Au(111)-22×√3 reconstruction. In both cases, the HBB molecule adsorbs on a bridge site, forming a ∼15° angle between the C-Br direction and [112̅]Au, indicating the site-specific molecule-substrate interactions. We show that the competition between intermolecular and molecule-substrate interactions determines molecule packing at the subnanometer scale, which will be helpful for crystal engineering, functional materials, and organic electronics. PMID:26905460

  19. On the stability of AuFe alloy nanoparticles

    International Nuclear Information System (INIS)

    AuFe nanoparticles with mean diameters d p = 13.2 nm have been prepared by inert-gas condensation. Conventional and high-resolution transmission electron microscopy and energy-dispersive x-ray spectroscopy investigations show that the particles are mostly icosahedra. Scanning transmission electron microscopy–energy-dispersive x-ray spectroscopy and scanning transmission electron microscopy–electron energy-loss spectroscopy show that the as-grown particles exhibit a core-shell structure. The shell is mainly composed of an amorphous FeO layer. Although Fe and Au are immiscible in the bulk, the particle cores are found to be homogeneously mixed at the atomic level with a local composition of around Au84Fe16 (at.%). AuFe nanoparticles exhibit a complex magnetic structure in which the core behaves as a spin glass with a freezing temperature of 35 K, whereas the amorphous FeO shell behaves as a ferro-ferrimagnetic system. On annealing above 300 °C, the AuFe icosahedra phases separate into their elemental constituents. Hence the as-grown AuFe icosahedra are metastable, thereby implying that the bulk phase diagram also applies for nanoscopic materials. (papers)

  20. Surface segregation phenomena in extended and nanoparticle surfaces of Cu-Au alloys

    Science.gov (United States)

    Li, Jonathan; Wang, Guofeng; Zhou, Guangwen

    2016-07-01

    Using density functional theory (DFT) and Monte Carlo (MC) simulations, we studied the surface segregation phenomena of Au atoms in the extended and nanoparticle surfaces of Cu-Au alloys. Our MC simulations predicted significant Au enrichment in the outermost layer of (111) and (100) extended surfaces, and Au enrichment in the two outermost layers of (110) extended surfaces. The equilibrium Cu-Au nanoparticles were predicted to develop into an Au-enriched shell structure, where Au atoms preferably segregate to the (100) facets while Cu atoms are mainly located on the (111) facet of the nanoparticles. Our simulation predictions agree with experimental measurements.

  1. Fragment production and collective motion in central Au+Au collisions

    International Nuclear Information System (INIS)

    The light charged particles (Z=1,2) and intermediate mass fragments (3 ≤ Z ≤ 15) emitted within the forward cone θ ≤ 30deg in Au+Au collisions at 150 A.MeV beam energy have been measured at SIS-Darmstadt, using the phase I set-up of the 4π detector. The central collisions have been selected by a cut on the total charged-particle multiplicity and a cut on the 'transverse momentum directivity' D, a vector sum of the transverse momenta of the measured charge particles. For the events of the central collisions, large transverse momenta are observed especially for clusters (Z≥3), and the multiplicity of intermediate mass fragments in the acceptance of our setup is about 4. The calculations of a statistical model, a modified version of FREESCO, are compared to the experimental results. A reasonably good agreement has been found between the calculations and the experimental data for the fragment productions and corresponding velocity distributions. The separation of collective and thermal motion for the emitted fragments has been attained. (orig.)

  2. Thermal Description of Particle Production in Au-Au Collisions at STAR Energies

    CERN Document Server

    Tawfik, A

    2013-01-01

    The hadron ratios measured in central Au-Au collisions are analysed by means of Hadron Resonance Gas (HRG) model over a wide range of nucleon-nucleon center-of-mass energies ranging from 7.7 to 200 GeV as offered by the STAR Beam Energy Scan I (BES-I). We restrict the discussion on STAR BES-I, because of large statistics and over all homogeneity of STAR measurements (one detector) against previous experiments. Over the last three decades, various heavy-ion experiments utilizing different detectors (different certainties) have been carried out. Regularities in produced particles at different energies haven been studied. The temperature and baryon chemical potential are deduced from fits of experimental ratios to thermal model calculations assuming chemical equilibrium. We find that the resulting freeze-out parameters using single hard-core value and point-like constituents of HRG are identical. This implies that the excluded-volume comes up with no effect on the extracted parameters. We compare the results wit...

  3. Bimodality in binary Au + Au collisions from 60 to 100 MeV/u

    Energy Technology Data Exchange (ETDEWEB)

    Pichon, M.; Tamain, B.; Bougault, R. [Caen Univ., Lab. de Physique Corpusculaire, IN2P3-CNRS, ISMRA, 14 (France)] [and others

    2003-03-01

    The deexcitation of quasi-projectiles (QP) released in binary Au on Au collisions as been studied from 60 to 100 MeV/u. Bimodality between two different decay patterns has been observed for intermediate violence collisions. The main experimental result is that the system jumps from one mode to the other on a narrow range of energy deposit and/or impact parameter. The sorting of the events (according to the violence of the collision) has been provided by the perpendicular energy of the light charged particles emitted on the quasi-target side. Such a sorting prevents spurious autocorrelation effects between the sorting variable and the observed mechanism. The two modes of the QP decay correspond on the one side to residue or fission fragments production, and on the other side to the multifragmentation channel. A detailed study has been performed in order to try to establish the origin of the observed bimodality in disentangling dynamical or geometrical effects from bulk matter properties linked with a liquid-gas type phase transition. The whole set of data is coherent with a dominant role of the deposited excitation energy as it is expected from theoretical arguments.(lattice gas model) in the framework of a liquid-gas phase transition picture. (authors)

  4. Phospholipid Encapsulated AuNR@Ag/Au Nanosphere SERS Tags with Environmental Stimulus Responsive Signal Property.

    Science.gov (United States)

    Su, Xueming; Wang, Yunqing; Wang, Wenhai; Sun, Kaoxiang; Chen, Lingxin

    2016-04-27

    Surface-enhanced Raman scattering (SERS) tags draw much attention due to the ultrasensitivity and multiplex labeling capability. Recently, a new kind of SERS tags was rationally designed by encapsulating metal nanoparticles with phospholipid bilayers, showing great potential in theranostics. The lipid bilayer coating confers biocompatibility and versatility to changing surface chemistry of the tag; however, its "soft" feature may influence SERS signal stability, which is rarely investigated. Herein, we prepared phospholipid-coated AuNR@Ag/Au nanosphere SERS tags by using three different kinds of Raman reporters, i.e., thio-containing 4-nitrothiophenol (NT), nitrogen-containing hydrophobic chromophore cyanine 7 monoacid (Cy7), and alkyl chain-chromophore conjugate 1,1'-dioctadecyl-3,3,3',3'-tetramethylindodicarbocyanine (DiD). It was found that signal responses were different upon additional stimulation which the tags may encounter in theranostic applications including the presence of detergent Triton X-100, lipid membrane, and photothermal treatment. Living-cell imaging also showed signal changing distinction. The different SERS signal performances were attributed to the different Raman reporter releasing behaviors from the tags. This work revealed that Raman reporter structure determined signal stability of lipid-coated SERS tags, providing guidance for the design of stimulus responsive tags. Moreover, it also implied the potential of SERS technique for real time drug release study of lipid based nanomedicine. PMID:27052206

  5. Reviewing hadron production in the SIS energy regime using new HADES Au+Au data

    International Nuclear Information System (INIS)

    Data on particle production in heavy ion collisions in the energy regime of 1-2 A GeV have been collected over almost three decades now. As most of the newly created hadrons are produced below or slightly above their free NN-thresholds, data are usually interpreted with the help of phenomenological models, rather than comparing to elementary reference measurements. Driven by advance in detector technology, more and more rare and penetrating probes have become accessible, and still keep challenging our knowledge about the properties of the created system and its dynamical evolution. The recently collected HADES data from Au+Au collisions at 1.23 A GeV represents in this energy regime the most advanced sample of heavy ion collisions in terms of precision and statistics (7*109 collected events). Using the yields and spectra of reconstructed hadrons (π+-, K+-, K0s, Λ) provides therefore the optimal bases to test state of the art models and to question the extent of our present understanding of hadron production.

  6. Dielectron production in Au$+$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; Angerami, A; Aoki, K; Apadula, N; Aramaki, Y; Asano, H; Aschenauer, E C; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Bandara, N S; Bannier, B; Barish, K N; Bassalleck, B; Bathe, S; Baublis, V; Baumgart, S; Bazilevsky, A; Beaumier, M; Beckman, S; Belmont, R; Berdnikov, A; Berdnikov, Y; Blau, D S; Bok, J S; Boyle, K; Brooks, M L; Bryslawskyj, J; Buesching, H; Bumazhnov, V; 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; Connors, M; Csanád, M; Csörgő, T; Dairaku, S; Danley, D; Datta, A; Daugherity, M S; David, G; 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; Edwards, S; Efremenko, Y V; 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; Gunji, T; Guo, L; Gustafsson, H -Å; 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; Haslum, E; Hayano, R; He, X; Hemmick, T K; Hester, T; Hill, J C; Hollis, R S; Homma, K; Hong, B; Horaguchi, T; Hori, Y; Hoshino, T; Hotvedt, N; Huang, J; Huang, S; Ichihara, T; Iinuma, H; Ikeda, Y; Imai, K; Imrek, J; Inaba, M; Iordanova, A; Isenhower, D; Issah, M; Ivanishchev, D; Jacak, B V; Javani, M; Jezghani, M; Jia, J; Jiang, X; Johnson, B M; 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; Khanzadeev, A; Kijima, K M; Kim, B I; Kim, C; Kim, D J; Kim, E -J; Kim, G W; Kim, H J; Kim, K -B; 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; Komatsu, Y; Komkov, B; 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, B; Lee, D M; 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, M X; Love, B; Lynch, D; Maguire, C F; Makdisi, Y I; Makek, M; Manion, A; Manko, V I; Mannel, E; Masumoto, S; 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; Miyachi, Y; Miyasaka, S; Mizuno, S; Mohanty, A K; Mohapatra, S; Montuenga, P; Moon, H J; Moon, T; Morrison, D P; Motschwiller, S; 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; Nederlof, A; Netrakanti, P K; Nihashi, M; Niida, T; Nishimura, S; Nouicer, R; Novak, T; Novitzky, N; Nyanin, A S; O'Brien, E; Ogilvie, C A; 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; Reynolds, D; Riabov, V; Riabov, Y; Richardson, E; Rinn, T; Roach, D; Roche, G; Rolnick, S D; Rosati, M; Rowan, Z; Rubin, J G; Sahlmueller, B; Saito, N; Sakaguchi, T; Sako, H; Samsonov, V; Sano, M; Sarsour, M; Sato, S; Sawada, S; Schaefer, B; Schmoll, B K; Sedgwick, K; Seidl, R; Sen, A; Seto, R; Sett, P; Sexton, A; Sharma, D; Shein, I; Shibata, T -A; Shigaki, K; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Sim, K S; Singh, B K; Singh, C P; Singh, V; Slunečka, M; Snowball, M; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Sukhanov, A; Sumita, T; Sun, J; Sziklai, J; Takagui, E M; Takahara, A; Taketani, A; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tennant, E; Themann, H; Tieulent, R; Timilsina, A; Todoroki, T; Tomášek, L; Tomášek, M; Torii, H; Towell, C L; Towell, R; Towell, R S; Tserruya, I; Tsuchimoto, Y; Tsuji, T; 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; White, A S; White, S N; Winter, D; Wolin, S; Woody, C L; Wysocki, M; Xia, B; Xue, L; Yalcin, S; Yamaguchi, Y L; Yang, R; Yanovich, A; Ying, J; 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

    We present measurements of $e^+e^-$ production at midrapidity in Au$+$Au collisions at $\\sqrt{s_{_{NN}}}$ = 200 GeV. The invariant yield is studied within the PHENIX detector acceptance over a wide range of mass ($m_{ee} <$ 5 GeV/$c^2$) and pair transverse momentum ($p_T$ $<$ 5 GeV/$c$), for minimum bias and for five centrality classes. The \\ee yield is compared to the expectations from known sources. In the low-mass region ($m_{ee}=0.30$--0.76 GeV/$c^2$) there is an enhancement that increases with centrality and is distributed over the entire pair \\pt range measured. It is significantly smaller than previously reported by the PHENIX experiment and amounts to $2.3\\pm0.4({\\rm stat})\\pm0.4({\\rm syst})\\pm0.2^{\\rm model}$ or to $1.7\\pm0.3({\\rm stat})\\pm0.3({\\rm syst})\\pm0.2^{\\rm model}$ for minimum bias collisions when the open-heavy-flavor contribution is calculated with {\\sc pythia} or {\\sc mc@nlo}, respectively. The inclusive mass and $p_T$ distributions as well as the centrality dependence are well repr...

  7. A first look at Au + Au collisions at RHIC energies using the PHOBOS detector

    Indian Academy of Sciences (India)

    Birger Back; M D Baker; D S Barton; R R Betts; R Bindel; A Budzanowski; W Busza; A Carroll; J Corbo; M P Decowski; E Garcia; N George; K Gulbrandsen; S Gushue; C Halliwell; J Hamblen; G A Heintzelman; C Henderson; D Hicks; D J Hofman; R Hollis; R Holyńiski; B Holzman; A Iordanova; E Johnson; J L Kane; J Katzy; N Khan; W Kucewicz; P Kulinich; C M Kuo; W T Lin; S Manly; D McLeod; J Michalowski; A C Mignerey; J Mülmenstädt; R Nouicer; A Olszewski; R Pak; I C Park; H Pernegger; M Rafelski; M Rbeiz; C Reed; L P Remsberg; M Reuter; C Roland; G Roland; L Rosenberg; J Sagerer; P Sarin; P Sawicki; W Skulski; S G Steadman; P Steinberg; G S F Stephans; M Stodulski; A Sukhanov; J-L Tang; R Teng; A Trzupek; C Vale; G J van Nieuwenhuizen; R Verdier; B Wadsworth; F L H Wolfs; B Wosiek; K Woźniak; A H Wuosmaa; B Wyslouch

    2003-05-01

    The PHOBOS detector has been used to study Au + Au collisions at $\\sqrt{S_{NN}}=56$, 130, and 200 GeV. Several global observables have been measured and the results are compared with theoretical models. These observables include the charged-particle multiplicity measured as a function of beam energy, pseudo-rapidity, and centrality of the collision. A unique feature of the PHOBOS detector is its almost complete angular coverage such that these quantities can be studied over a pseudo-rapidity interval of ||≤ 5.4. This allows for an almost complete integration of the total charged particle yield, which is found to be about $N^{\\text{tot}}_{\\text{ch}}=4500± 470$ at $\\sqrt{S_{NN}}=130$ GeV and $N^{\\text{tot}}_{\\text{ch}}=5300± 530$ at $\\sqrt{S_{NN}}$ GeV. The ratio of anti-particles to particles emitted in the mid-rapidity region has also been measured using the PHOBOS magnetic spectrometer. Of particular interest is the ratio of anti-protons to protons in the mid-rapidity region, which was found to be $\\overline{p}/p= 0.6± 0.04$(stat) ± 0.06(syst) at $\\sqrt{S_{NN}}=130$ GeV. This high value suggests that an almost baryon-free region has been produced in the collisions.

  8. Azimuthal anisotropy in U+U and Au+Au collisions at RHIC

    CERN Document Server

    Adamczyk, L; Agakishiev, G; Aggarwal, M M; Ahammed, Z; Alekseev, I; Alford, J; Aparin, A; Arkhipkin, D; Aschenauer, E C; Averichev, G S; Bairathi, V; Banerjee, A; Bellwied, R; Bhasin, A; Bhati, A K; Bhattarai, P; Bielcik, J; Bielcikova, J; Bland, L C; Bordyuzhin, I G; Bouchet, J; Brandin, A V; Bunzarov, I; Butterworth, J; Caines, H; Sánchez, M Calderón de la Barca; Campbell, J M; Cebra, D; Cervantes, M C; Chakaberia, I; Chaloupka, P; Chang, Z; Chattopadhyay, S; Chen, J H; Chen, X; Cheng, J; Cherney, M; Christie, W; Contin, G; Crawford, H J; Das, S; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; Derevschikov, A A; di Ruzza, B; Didenko, L; Dilks, C; Dong, X; Drachenberg, J L; Draper, J E; Du, C M; Dunkelberger, L E; Dunlop, J C; Efimov, L G; Engelage, J; Eppley, G; Esha, R; Evdokimov, O; Eyser, O; Fatemi, R; Fazio, S; Federic, P; Fedorisin, J; Feng, Z; Filip, P; Fisyak, Y; Flores, C E; Fulek, L; Gagliardi, C A; Garand, D; Geurts, F; Gibson, A; Girard, M; Greiner, L; Grosnick, D; Gunarathne, D S; Guo, Y; Gupta, A; Gupta, S; Guryn, W; Hamad, A; Hamed, A; Haque, R; Harris, J W; He, L; Heppelmann, S; Hirsch, A; Hoffmann, G W; Hofman, D J; Horvat, S; Huang, B; Huang, H Z; Huang, X; Huck, P; Humanic, T J; Igo, G; Jacobs, W W; Jang, H; Jiang, K; Judd, E G; Kabana, S; Kalinkin, D; Kang, K; Kauder, K; Ke, H W; Keane, D; Kechechyan, A; Khan, Z H; Kikola, D P; Kisel, I; Kisiel, A; Kochenda, L; Koetke, D D; Kollegger, T; Kosarzewski, L K; Kraishan, A F; Kravtsov, P; Krueger, K; Kulakov, I; Kumar, L; Kycia, R A; Lamont, M A C; Landgraf, J M; Landry, K D; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; Li, X; Li, Z M; Li, Y; Li, W; Li, C; Lisa, M A; Liu, F; Ljubicic, T; Llope, W J; Lomnitz, M; Longacre, R S; Luo, X; Ma, G L; Ma, R; Ma, Y G; Ma, L; Magdy, N; Majka, R; Manion, A; Margetis, S; Markert, C; Masui, H; Matis, H S; McDonald, D; Meehan, K; Minaev, N G; Mioduszewski, S; Mishra, D; Mohanty, B; Mondal, M M; Morozov, D A; Mustafa, M K; Nandi, B K; Nasim, Md; Nayak, T K; Nigmatkulov, G; Nogach, L V; Noh, S Y; Novak, J; Nurushev, S B; Odyniec, G; Ogawa, A; Oh, K; Okorokov, V; Olvitt, D; Page, B S; Pak, R; Pan, Y X; Pandit, Y; Panebratsev, Y; Pawlik, B; Pei, H; Perkins, C; Peterson, A; Pile, P; Planinic, M; Pluta, J; Poljak, N; Poniatowska, K; Porter, J; Posik, M; Poskanzer, A M; Putschke, J; Qiu, H; Quintero, A; Ramachandran, S; Raniwala, R; Raniwala, S; Ray, R L; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Roy, A; Ruan, L; Rusnak, J; Rusnakova, O; Sahoo, N R; Sahu, P K; Sakrejda, I; Salur, S; Sandweiss, J; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schmidke, W B; Schmitz, N; Seger, J; Seyboth, P; Shah, N; Shahaliev, E; Shanmuganathan, P V; Shao, M; Sharma, M K; Sharma, B; Shen, W Q; Shi, S S; Shou, Q Y; Sichtermann, E P; Sikora, R; Simko, M; Skoby, M J; Smirnov, N; Smirnov, D; Song, L; Sorensen, P; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stepanov, M; Stock, R; Strikhanov, M; Stringfellow, B; Sumbera, M; Summa, B; Sun, Z; Sun, X M; Sun, Y; Sun, X; Surrow, B; Svirida, N; Szelezniak, M A; Tang, Z; Tang, A H; Tarnowsky, T; Tawfik, A; Thomas, J H; Timmins, A R; Tlusty, D; Tokarev, M; Trentalange, S; Tribble, R E; Tribedy, P; Tripathy, S K; Trzeciak, B A; Tsai, O D; Ullrich, T; Underwood, D G; Upsal, I; Van Buren, G; van Nieuwenhuizen, G; Vandenbroucke, M; Varma, R; Vasiliev, A N; Vertesi, R; Videbæk, F; Viyogi, Y P; Vokal, S; Voloshin, S A; Vossen, A; Wang, G; Wang, H; Wang, J S; Wang, Y; Wang, F; Webb, J C; Webb, G; Wen, L; Westfall, G D; Wieman, H; Wissink, S W; Witt, R; Wu, Y F; Xiao, Z G; Xie, W; Xin, K; Xu, Y F; Xu, Q H; Xu, H; Xu, N; Xu, Z; Yang, Y; Yang, C; Yang, S; Yang, Q; Ye, Z; Yepes, P; Yi, L; Yip, K; Yoo, I -K; Yu, N; Zbroszczyk, H; Zha, W; Zhang, J B; Zhang, Z; Zhang, J; Zhang, S; Zhang, X P; Zhang, Y; Zhao, J; Zhong, C; Zhou, L; Zhu, X; Zoulkarneeva, Y; Zyzak, M

    2015-01-01

    Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, $v_2\\{2\\}$ and $v_2\\{4\\}$, for charged hadrons from U+U collisions at $\\sqrt{s_{\\rm NN}}$ = 193 GeV and Au+Au collisions at $\\sqrt{s_{\\rm NN}}$ = 200 GeV. Nearly fully overlapping collisions are selected based on the amount of energy deposited by spectators in the STAR Zero Degree Calorimeters (ZDCs). Within this sample, the observed dependence of $v_2\\{2\\}$ on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U+U collisions. An initial-state model with gluon saturation describes the slope of $v_2\\{2\\}$ as a function of multiplicity in central collisions better than one based on Glauber with a two-component multiplicity model.

  9. Bimodality in binary Au + Au collisions from 60 to 100 MeV/u

    International Nuclear Information System (INIS)

    The deexcitation of quasi-projectiles (QP) released in binary Au on Au collisions as been studied from 60 to 100 MeV/u. Bimodality between two different decay patterns has been observed for intermediate violence collisions. The main experimental result is that the system jumps from one mode to the other on a narrow range of energy deposit and/or impact parameter. The sorting of the events (according to the violence of the collision) has been provided by the perpendicular energy of the light charged particles emitted on the quasi-target side. Such a sorting prevents spurious autocorrelation effects between the sorting variable and the observed mechanism. The two modes of the QP decay correspond on the one side to residue or fission fragments production, and on the other side to the multifragmentation channel. A detailed study has been performed in order to try to establish the origin of the observed bimodality in disentangling dynamical or geometrical effects from bulk matter properties linked with a liquid-gas type phase transition. The whole set of data is coherent with a dominant role of the deposited excitation energy as it is expected from theoretical arguments.(lattice gas model) in the framework of a liquid-gas phase transition picture. (authors)

  10. Maximization of surface-enhanced transversal magneto-optic Kerr effect in Au/Co/Au thin films

    CERN Document Server

    Herreño-Fierro, César Aurelio

    2014-01-01

    In order to maximize the transversal magneto-optic Kerr effect (T-MOKE) of a Au/Co/Au structure, we propose a method to obtain the optimum thickness values. A criteria based on preserving good plasmonic properties has been included as part of this method. Using the theoretical prediction, we grew Au/Co/Au trilayers and perform optical andMO characterization using the Kretschmann configuration. The results admit very easy interpretation in terms of the interaction between the magneto-optical and plasmonic properties dictating the optimal thicknesses of the structure. Moreover, we have grown and characterized the optimized structure finding good agreement with theory reaching, for a 532nm green laser, amaximal surface magneto-optic (MO) signal enhancement of close to nine folds with respect to the signal without plasmonic excitation.

  11. Scaling properties of proton and antiproton production in sqrt[s(NN)]=200 GeV Au+Au collisions.

    Science.gov (United States)

    Adler, S S; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Alexander, J; Amirikas, R; Aphecetche, L; Aronson, S H; Averbeck, R; Awes, T C; Azmoun, R; Babintsev, V; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bazilevsky, A; Belikov, S; Berdnikov, Y; Bhagavatula, S; Boissevain, J G; Borel, H; Borenstein, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Chai, J-S; Chand, P; Chang, W C; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J; Choudhury, R K; Chujo, T; Cianciolo, V; Cobigo, Y; Cole, B A; Constantin, P; d'Enterria, D G; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Dietzsch, O; Drapier, O; Drees, A; du Rietz, R; Durum, A; Dutta, D; Efremenko, Y V; El Chenawi, K; Enokizono, A; En'yo, H; Esumi, S; Ewell, L; Fields, D E; Fleuret, F; Fokin, S L; Fox, B D; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Gogiberidze, G; Gonin, M; Gosset, J; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grosse Perdekamp, G; Guryn, W; Gustafsson, H-A; Hachiya, T; Haggerty, J S; Hamagaki, H; Hansen, A G; Hartouni, E P; Harvey, M; Hayano, R; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Holzmann, W; Homma, K; Hong, B; Hoover, A; Ichihara, T; Ikonnikov, V V; Imai, K; Isenhower, L D; Ishihara, M; Issah, M; Isupov, A; Jacak, B V; Jang, W Y; Jeong, Y; Jia, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kametani, S; Kamihara, N; Kang, J H; Kapoor, S S; Katou, K; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, D W; Kim, E; Kim, G-B; Kim, H J; Kistenev, E; Kiyomichi, A; Kiyoyama, K; Klein-Boesing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kopytine, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kuberg, C H; Kurita, K; Kuroki, Y; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Ladygin, V; Lajoie, J G; Lebedev, A; Leckey, S; Lee, D M; Lee, S; Leitch, M J; Li, X H; Lim, H; Litvinenko, A; Liu, M X; Liu, Y; Maguire, C F; Makdisi, Y I; Malakhov, A; Manko, V I; Mao, Y; Martinez, G; Marx, M D; Masui, H; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Messer, F; Miake, Y; Milan, J; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagle, J L; Nakamura, T; Nandi, B K; Nara, M; Newby, J; Nilsson, P; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Ono, M; Onuchin, V; Oskarsson, A; Otterlund, I; Oyama, K; Ozawa, K; Pal, D; Palounek, A P T; Pantuev, V S; Papavassiliou, V; Park, J; Parmar, A; Pate, S F; Peitzmann, T; Peng, J-C; Peresedov, V; Pinkenburg, C; Pisani, R P; Plasil, F; Purschke, M L; Purwar, A; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosnet, P; Ryu, S S; Sadler, M E; Saito, N; Sakaguchi, T; Sakai, M; Sakai, S; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Semenov, V; Seto, R; Shaw, M R; Shea, T K; Shibata, T-A; Shigaki, K; Shiina, T; Silva, C L; Silvermyr, D; Sim, K S; Singh, C P; Singh, V; Sivertz, 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; Sullivan, J P; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarján, P; Tepe, J D; Thomas, T L; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tuli, S K; Tydesjö, H; Tyurin, N; Van Hecke, H W; Velkovska, J; Velkovsky, M; Villatte, L; Vinogradov, A A; Volkov, M A; Vznuzdaev, E; Wang, X R; Watanabe, Y; White, S N; Wohn, F K; Woody, C L; Xie, W; Yang, Y; Yanovich, A; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zolin, L

    2003-10-24

    We report on the yield of protons and antiprotons, as a function of centrality and transverse momentum, in Au+Au collisions at sqrt[s(NN)]=200 GeV measured at midrapidity by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider. In central collisions at intermediate transverse momenta (1.5Au+Au, p+p, and e(+)e(-) collisions. This enhancement is limited to p(T)<5 GeV/c as deduced from the ratio of charged hadrons to pi(0) measured in the range 1.5

  12. Fabrication of Au nanostructures in the process of amalgam formation followed by Au-Hg alloy thermal decomposition

    International Nuclear Information System (INIS)

    Au films deposited under ultra-high vacuum conditions on air-cleaved mica substrates were exposed in situ to Hg vapor (residual gas pressure ∼1x10-7 Pa, with Hg vapor pressure of 0.24 Pa). This led to transformation of continuous gold film into isolated amalgam islands of nanometer scale. The changes of Au thin film surface topography caused by amalgamation carried out within ∼40 h were studied by the atomic force microscopy method, while the phase transition in the bulk of Hg-dosed Au films was monitored by means of X-ray diffraction. The island's morphology varies from irregular, ramified structures on terraces to compact shapes along the steps on the mica substrate. After thermal decomposition of the amalgam, thin gold films consisting of isolated Au nanostructures on mica can be obtained

  13. Strangeness Enhancement in Cu+Cu and Au+Au Collisions at \\sqrt{s_{NN}} = 200 GeV

    CERN Document Server

    Agakishiev, H; Ahammed, Z; Alakhverdyants, A V; Alekseev, I; Alford, J; Anderson, B D; Anson, C D; Arkhipkin, D; Averichev, G S; Balewski, J; Barnby, L S; Beavis, D R; Behera, N K; Bellwied, R; Betancourt, M J; Betts, R R; Bhasin, A; Bhati, A K; Bichsel, H; Bielcik, J; Bielcikova, J; Biritz, B; Bland, L C; Borowski, W; Bouchet, J; Braidot, E; Brandin, A V; Bridgeman, A; Brovko, S G; Bruna, E; Bueltmann, S; Bunzarov, I; Burton, T P; Cai, X Z; Caines, H; Sánchez, M Calderón de la Barca; Cebra, D; Cendejas, R; Cervantes, M C; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, J Y; Chen, L; Cheng, J; Cherney, M; Chikanian, A; Choi, K E; Christie, W; Chung, P; Codrington, M J M; Corliss, R; Cramer, J G; Crawford, H J; Dash, S; Leyva, A Davila; De Silva, L C; Debbe, R R; Dedovich, T G; Derevschikov, A A; de Souza, R Derradi; Didenko, L; Djawotho, P; Dogra, S M; Dong, X; Drachenberg, J L; Draper, J E; Dunlop, J C; Efimov, L G; Elnimr, M; Engelage, J; Eppley, G; Estienne, M; Eun, L; Evdokimov, O; Fatemi, R; Fedorisin, J; Fersch, R G; Filip, P; Finch, E; Fine, V; Fisyak, Y; Gagliardi, C A; Gangadharan, D R; Geromitsos, A; Geurts, F; Ghosh, P; Gorbunov, Y N; Gordon, A; Grebenyuk, O; Grosnick, D; Guertin, S M; Gupta, A; Guryn, W; Haag, B; Hajkova, O; Hamed, A; Han, L-X; Harris, J W; Hays-Wehle, J P; Heinz, M; Heppelmann, S; Hirsch, A; Hjort, E; Hoffmann, G W; Hofman, D J; Huang, B; Huang, H Z; Humanic, T J; Huo, L; Igo, G; Jacobs, P; Jacobs, W W; Jones, P G; Jena, C; Jin, F; Joseph, J; Judd, E G; Kabana, S; Kang, K; Kapitan, J; Kauder, K; Ke, H; Keane, D; Kechechyan, A; Kettler, D; Kikola, D P; Kiryluk, J; Kisiel, A; Kizka, V; Knospe, A G; Koetke, D D; Kollegger, T; Konzer, J; Koralt, I; Koroleva, L; Korsch, W; Kotchenda, L; Kouchpil, V; Kravtsov, P; Krueger, K; Krus, M; Kumar, L; Kurnadi, P; Lamont, M A C; Landgraf, J M; LaPointe, S; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; Leight, W; LeVine, M J; Li, C; Li, L; Li, N; Li, W; Li, X; Li, X; Li, Y; Li, Z M; Lisa, M A; Liu, F; Liu, H; Liu, J; Ljubicic, T; Llope, W J; Longacre, R S; Love, W A; Lu, Y; Lukashov, E V; Luo, X; Ma, G L; Ma, Y G; Mahapatra, D P; Majka, R; Mall, O I; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Masui, H; Matis, H S; Matulenko, Yu A; McDonald, D; McShane, T S; Meschanin, A; Milner, R; Minaev, N G; Mioduszewski, S; Mischke, A; Mitrovski, M K; Mohanty, B; Mondal, M M; Morozov, B; Morozov, D A; Munhoz, M G; Naglis, M; Nandi, B K; Nayak, T K; Netrakanti, P K; Nelson, J M; Nogach, L V; Nurushev, S B; Odyniec, G; Ogawa, A; Oh, K; Ohlson, A; Okorokov, V; Oldag, E W; Olson, D; Pachr, M; Page, B S; Pal, S K; Pandit, Y; Panebratsev, Y; Pawlak, T; Pei, H; Peitzmann, T; Perkins, C; Peryt, W; Phatak, S C; Pile, P; Planinic, M; Ploskon, M A; Pluta, J; Plyku, D; Poljak, N; Poskanzer, A M; Potukuchi, B V K S; Powell, C B; Prindle, D; Pruneau, C; Pruthi, N K; Pujahari, P R; Putschke, J; Qiu, H; Raniwala, R; Raniwala, S; Ray, R L; Redwine, R; Reed, R; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Rose, A; Ruan, L; Rusnak, J; Sahoo, N R; Sakai, S; Sakrejda, I; Sakuma, T; Salur, S; Sandweiss, J; Sangaline, E; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schuster, T R; Seele, J; Seger, J; Selyuzhenkov, I; Seyboth, P; Shahaliev, E; Shao, M; Sharma, M; Shi, S S; Shou, Q Y; Sichtermann, E P; Simon, F; Singaraju, R N; Skoby, M J; Smirnov, N; Spinka, H M; Srivastava, B; Stanislaus, T D S; Staszak, D; Steadman, S G; Stevens, J R; Stock, R; Strikhanov, M; Stringfellow, B; Suaide, A A P; Suarez, M C; Subba, N L; Sumbera, M; Sun, X M; Sun, Y; Sun, Z; Surrow, B; Svirida, D N; Symons, T J M; de Toledo, A Szanto; Takahashi, J; Tang, A H; Tang, Z; Tarini, L H; Tarnowsky, T; Thein, D; Thomas, J H; Tian, J; Timmins, A R; Tlusty, D; Tokarev, M; Tram, V N; Trentalange, S; Tribble, R E; Tribedy, P; Tsai, O D; Ullrich, T; Underwood, D G; Van Buren, G; van Nieuwenhuizen, G; Vanfossen, J A; Jr.,; Varma, R; Vasconcelos, G M S; Vasiliev, A N; Videbæk, F; Viyogi, Y P; Vokal, S; Wada, M; Walker, M; Wang, F; Wang, G; Wang, H; Wang, J S; Wang, Q; Wang, X L; Wang, Y; Webb, G; Webb, J C; Westfall, G D; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Witzke, W; Wu, Y F; Xiao, Z; Xie, W; Xu, H; Xu, N; Xu, Q H; Xu, W; Xu, Y; Xu, Z; Xue, L; Yang, Y; Yepes, P; Yip, K; Yoo, I-K; Zawisza, M; Zbroszczyk, H; Zhan, W; Zhang, J B; Zhang, S; Zhang, W M; Zhang, X P; Zhang, Y; Zhang, Z P; Zhao, J; Zhong, C; Zhou, W; Zhu, X; Zhu, Y H; Zoulkarneev, R; Zoulkarneeva, Y

    2011-01-01

    We report new STAR measurements of mid-rapidity yields for the $\\Lambda$, $\\bar{\\Lambda}$, $K^{0}_{S}$, $\\Xi^{-}$, $\\bar{\\Xi}^{+}$, $\\Omega^{-}$, $\\bar{\\Omega}^{+}$ particles in Cu+Cu collisions at \\sNN{200}, and mid-rapidity yields for the $\\Lambda$, $\\bar{\\Lambda}$, $K^{0}_{S}$ particles in Au+Au at \\sNN{200}. We show that at a given number of participating nucleons, the production of strange hadrons is higher in Cu+Cu collisions than in Au+Au collisions at the same center-of-mass energy. We find that aspects of the enhancement factors for all particles can be described by a parameterization based on the fraction of participants that undergo multiple collisions. Such a parameterization may be relevant in the core-corona or string excitation/breaking hadron production schemes.

  14. Charged-Particle Pseudorapidity Density Distributions from Au+Au Collisions at (sNN) = 130 GeV

    Science.gov (United States)

    Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hołyński, R.; Holzman, B.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Mülmenstädt, J.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2001-09-01

    The charged-particle pseudorapidity density dNch/dη has been measured for Au+Au collisions at (sNN) = 130 GeV at RHIC, using the PHOBOS apparatus. The total number of charged particles produced for the 3% most-central Au+Au collisions for \\|η\\|<=5.4 is found to be 4200+/-470. The evolution of dNch/dη with centrality is discussed, and compared to model calculations and to data from proton-induced collisions. The data show an enhancement in charged-particle production at midrapidity, while in the fragmentation regions, the results are consistent with expectations from pp and pA scattering.

  15. Centrality definition using mid-rapidity ET distributions from p+Be to Au+Au at AGS energies

    International Nuclear Information System (INIS)

    Measurements by the E802 Collaboration of the A-dependence and pseudorapidity interval (δη) dependence of mid-rapidity ET distributions in a half-azimuth electromagnetic calorimeter are presented for p+Be, p+Au, O+Cu, Si+Au and Au+Au collisions at the BNL-AGS. The issues addressed are 1) whether the shapes of the upper edges of the ET distributions vary with δη similarly to the variation in shapes of mid-rapidity charged particle distributions and 2) how small a δη interval would still give a meaningful characterization of the 'nuclear geometry' of a reaction. A new way of plotting ET distributions was found from which the reaction dynamics could be read directly

  16. Controlled building of CdSe@ZnS/Au and CdSe@ZnS/ Au2S/Au nanohybrids

    Institute of Scientific and Technical Information of China (English)

    Raquel E. Galian[1; Pilar Diaz[1; Antonio Ribera[1; Alejandro Rincon-Bertolin[1; Said Agouram[2; Julia Perez-Prieto[1

    2015-01-01

    The addition of Au3. to spherical amine-capped CdSe@ZnS nanoparticles in toluene at room temperature and under darkness can lead to ternary CdSe@ZnS/Au nanohybrids. We demonstrate that this happens only when the nanoparticles possess a relatively thin ZnS shell, thus showing that thickness plays a key role in gold deposition on the CdSe@ZnS nanoparticle surface. Our hypothesis is that the amine ligand acts as the reductant of Au3+ ions into Au+ ions, whose affinity for sulfur would keep them at the CdSe@ZnS surface. This interaction stabilizes the Au+ ion, making it less prone to reduction than a non-coordinated Au+ ion. In CdSe@ZnS with a thin shell, Au+ ions at the surface of, or most probably within, the ZnS shell cause the transfer of Cd2+ ions into the solution. Subsequently, the core Se2- anion, which is a better reductant than the shell S2- reduces Au+ ions to Au(0), and large gold nanoparticles (AuNPs) are quickly deposited on the CdSe@ZnS surface in room temperature process, leading to ternary CdSe@ZnS/Au nanohybrids. In solution, these ternary nanohybrids progressively transform into quaternary CdSe@ZnS/Au2S/Au nanohybrids due to the reaction of the shell S2- anion with the remaining Au+ at the CdSe@ZnS surface, thus leading to the growth of Au2S nanoparticles on the CdSe@ZnS surface while Zn concomitantly leaches from the nanohybrid into the solution. Photoirradiation of the heterostructures with visible light enhances their emission efficiency. Comparatively, irradiation of the precursors, i.e., CdSe@ZnS nanoparticles, causes a drastic decrease in their emission accompanied by a blue shift of their emission maximum. The optical properties of these nanohybrids were analyzed by absorption and fluorescence (steady-state and time-resolved) spectroscopy, and the composition of the samples and the chemical states were determined by energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy

  17. Excitonic luminescence of ZnSe single crystals doped with Au

    International Nuclear Information System (INIS)

    Photoluminescence spectra of ZnSe single crystals doped with Au during a long high-temperature treatment of as-grown crystals in Zn+Au or Se+Au melts are investigated in the temperature range from 83 to 300 K. The Au-doping from Zn+Au melt leads to the formation of both simple defects (Aui donors and AuZn acceptors) and acceptor associates (AuZn-Aui). The edge luminescence is attributed to radiative annihilation of Aui and VSe donor-bound excitons. The edge spectra of the crystals doped with Au from Se+Au melt contain the band ascribed to radiative annihilation of AuZn acceptor-bound excitons

  18. Au(n)Hg(m) clusters: mercury aurides, gold amalgams, or van der Waals aggregates?

    Science.gov (United States)

    Zaleski-Ejgierd, Patryk; Pyykkö, Pekka

    2009-11-12

    The class of bimetallic clusters, Au(n)M(m) (M = Zn, Cd, Hg), is calculated at the ab initio level using the DFT, RI-MP2, and CCSD(T) methods. For the triatomic Au2M (M = Zn, Cd), the auride-type linear Au-M-Au structures are preferred; for Au2Hg, the linear Au-Au-Hg "amalgam" is preferred. The mixed cation [HgAuHg]+, an analog of the known solid-state species Hg32+, is predicted. For larger Au(n)Hg(m) clusters, the results are similar to the isoelectronic Au(n)M- anions. Several local minima and transition states are identified. All are found to be planar. PMID:19228004

  19. Elliptic flow of identified hadrons in Au+Au collisions at √(sNN)=200 GeV

    International Nuclear Information System (INIS)

    The anisotropy parameter (v2), the second harmonic of the azimuthal particle distribution, has been measured with the PHENIX detector in Au+Au collisions at √(sNN)=200 GeV for identified and inclusive charged particle production at central rapidities (|η|2 of mesons falls below that of (anti)baryons for pT>2 GeV/c, in marked contrast to the predictions of a hydrodynamical model. A quark-coalescence model is also investigated

  20. Elliptic flow of identified hadrons in Au+Au collisions at sqrt sNN =200 GeV.

    Science.gov (United States)

    Adler, S S; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Alexander, J; Amirikas, R; Aphecetche, L; Aronson, S H; Averbeck, R; Awes, T C; Azmoun, R; Babintsev, V; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bazilevsky, A; Belikov, S; Berdnikov, Y; Bhagavatula, S; Boissevain, J G; Borel, H; Borenstein, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Chai, J-S; Chand, P; Chang, W C; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J; Choudhury, R K; Chujo, T; Cianciolo, V; Cobigo, Y; Cole, B A; Constantin, P; D'Enterria, D G; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Dietzsch, O; Drapier, O; Drees, A; du Rietz, R; Durum, A; Dutta, D; Efremenko, Y V; El Chenawi, K; Enokizono, A; En'yo, H; Esumi, S; Ewell, L; Fields, D E; Fleuret, F; Fokin, S L; Fox, B D; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Gogiberidze, G; Gonin, M; Gosset, J; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grosse Perdekamp, M; Guryn, W; Gustafsson, H-A; Hachiya, T; Haggerty, J S; Hamagaki, H; Hansen, A G; Hartouni, E P; Harvey, M; Hayano, R; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Holzmann, W; Homma, K; Hong, B; Hoover, A; Ichihara, T; Ikonnikov, V V; Imai, K; Isenhower, L D; Ishihara, M; Issah, M; Isupov, A; Jacak, B V; Jang, W Y; Jeong, Y; Jia, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kametani, S; Kamihara, N; Kang, J H; Kapoor, S S; Katou, K; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, D W; Kim, E; Kim, G-B; Kim, H J; Kistenev, E; Kiyomichi, A; Kiyoyama, K; Klein-Boesing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kopytine, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kuberg, C H; Kurita, K; Kuroki, Y; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Ladygin, V; Lajoie, J G; Lebedev, A; Leckey, S; Lee, D M; Lee, S; Leitch, M J; Li, X H; Lim, H; Litvinenko, A; Liu, M X; Liu, Y; Maguire, C F; Makdisi, Y I; Malakhov, A; Manko, V I; Mao, Y; Martinez, G; Marx, M D; Masui, H; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Messer, F; Miake, Y; Milan, J; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagle, J L; Nakamura, T; Nandi, B K; Nara, M; Newby, J; Nilsson, P; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Ono, M; Onuchin, V; Oskarsson, A; Otterlund, I; Oyama, K; Ozawa, K; Pal, D; Palounek, A P T; Pantuev, V S; Papavassiliou, V; Park, J; Parmar, A; Pate, S F; Peitzmann, T; Peng, J-C; Peresedov, V; Pinkenburg, C; Pisani, R P; Plasil, F; Purschke, M L; Purwar, A; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosnet, P; Ryu, S S; Sadler, M E; Saito, N; Sakaguchi, T; Sakai, M; Sakai, S; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Semenov, V; Seto, R; Shaw, M R; Shea, T K; Shibata, T-A; Shigaki, K; Shiina, T; Silva, C L; Silvermyr, D; Sim, K S; Singh, C P; Singh, V; Sivertz, 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; Sullivan, J P; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarján, P; Tepe, J D; Thomas, T L; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tuli, S K; Tydesjö, H; Tyurin, N; van Hecke, H W; Velkovska, J; Velkovsky, M; Villatte, L; Vinogradov, A A; Volkov, M A; Vznuzdaev, E; Wang, X R; Watanabe, Y; White, S N; Wohn, F K; Woody, C L; Xie, W; Yang, Y; Yanovich, A; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zolin, L

    2003-10-31

    The anisotropy parameter (v(2)), the second harmonic of the azimuthal particle distribution, has been measured with the PHENIX detector in Au+Au collisions at sqrt[s(NN)]=200 GeV for identified and inclusive charged particle production at central rapidities (|eta|2 GeV/c, in marked contrast to the predictions of a hydrodynamical model. A quark-coalescence model is also investigated. PMID:14611277

  1. Azimuthally sensitive hanbury brown-twiss interferometry in Au + Au collisions sqrt S sub NN = 200 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Adams, J.; Adler, C.; Aggarwal, M.M.; Ahammed, Z.; Amonett, J.; Anderson, B.D.; Arkhipkin, D.; Averichev, G.S.; Badyal, S.K.; Balewski, J.; Barannikova, O.; Barnby, L.S.; Baudot, J.; Bekele, S.; Belaga, V.V.; Bellwied, R.; Berger, J.; Bezverkhny, B.I.; Bhardwaj, S.; Bhati, A.K.; Bichsel, H.; Billmeier, A.; Bland, L.C.; Blyth, C.O.; Bonner, B.E.; Botje, M.; Boucham, A.; Brandin, A.; Bravar, A.; Cadman, R.V.; Cai, X.Z.; Caines, H.; Calderon de la Barca Sanchez, M.; Carroll, J.; Castillo, J.; Cebra, D.; Chaloupka, P.; Chattopadhyay, S.; Chen, H.F.; Chen, Y.; Chernenko, S.P.; Cherney, M.; Chikanian, A.; Christie, W.; Coffin, J.P.; Cormier, T.M.; Cramer, J.G.; Crawford, H.J.; Das, D.; Das, S.; Derevschikov, A.A.; Didenko, L.; Dietel, T.; Dong, W.J.; Dong, X.; Draper, J.E.; Du, F.; Dubey, A.K.; Dunin, V.B.; Dunlop, J.C.; Dutta Majumdar, M.R.; Eckardt, V.; Efimov, L.G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Faine, V.; Faivre, J.; Fatemi, R.; Filimonov, K.; Filip, P.; Finch, E.; Fisyak, Y.; Flierl, D.; Foley, K.J.; Fu, J.; Gagliardi, C.A.; Gagunashvili, N.; Gans, J.; Gaudichet, L.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J.E.; Grachov, O.; Grebenyuk, O.; Gronstal, S.; Grosnick, D.; Guertin, S.M.; Gupta, A.; Gutierrez, T.D.; Hallman, T.J.; Hamed, A.; Hardtke, D.; Harris, J.W.; Heinz, M.; Henry, T.W.; Heppelmann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffmann, G.W.; Horsley, M.; Huang, H.Z.; Huang, L.S.; Hughes, E.; Humanic, T.J.; Igo, G.; Ishihara, A.; Jacobs, P.; Jacobs, W.W.; Janik, M.; Jiang, H.; Johnson, I.; Jones, P.G.; Judd, E.G.; Kabana, S.; Kaplan, M.; Keane, D.; Khodyrev, V.Yu.; Kiryluk, J.; Kisiel, A.; Klay, J.; Klein, S.R.; Klyachko, A.; Koetke, D.D.; Kollegger, T.; Kopytine, M.; Kotchenda, L.; Kovalenko, A.D.; Kramer, M.; Kravtsov, V.I.; Kravtsov, P.; Krueger, K.; Kuhn, C.; Kulikov, A.I.; Kumar, A.; Kunde, G.J.; Kunz, C.L.; Kutuev, R.Kh.; Kuznetsov, A.A.; Lamont, M.A.C.; et al.

    2004-06-30

    We present the results of a systematic study of the shape of the pion distribution in coordinate space at freeze-out in Au+Au collisions at RHIC using two-pion Hanbury Brown-Twiss (HBT) interferometry. Oscillations of the extracted HBT radii vs. emission angle indicate sources elongated perpendicular to the reaction plane. The results indicate that the pressure and expansion time of the collision system are not sufficient to completely quench its initial shape.

  2. Au - Be/Ru/Au multilayer metallization as a stable ohmic contact scheme to p-type InP

    Science.gov (United States)

    Malina, V.; Moro, L.; Micheli, V.; Mojzes, I.

    1996-07-01

    An attempt has been made to improve the electrical and metallurgical stability of Au - Be alloyed contacts to moderately doped p-type InP by minimizing the thickness of the Au - Be contact layer and using an Ru layer as a new, more effective diffusion barrier between the Au - Be and a thick Au top layer. It was found that the Au - Be contact layer only 40 - 50 nm thick is sufficient to give excellent ohmic contacts with specific contact resistance values as low as 0268-1242/11/7/025/img6 and 0268-1242/11/7/025/img7 (for 0268-1242/11/7/025/img8 and 0268-1242/11/7/025/img9 respectively). When subjected to an aging test at 0268-1242/11/7/025/img10 for 50 h in 0268-1242/11/7/025/img11 gas, the 50 nm Au - Be/50 nm Ru/300 nm Au contacts alloyed at an optimum temperature of about 0268-1242/11/7/025/img12 exhibit good thermal stability and no substantial increase in the specific contact resistance. The remarkable metallurgical stability of such contacts was confirmed by secondary neutral mass spectroscopy (SNMS) in-depth profile measurements. A comparison with the previously investigated diffusion barrier metals (such as Cr, Ti, Pt, etc) shows that the Ru layer is a much better barrier against the migration of Au into the InP substrate and, at the same time, it suppresses the out-diffusion of In and P from the semiconductor.

  3. Pion Interferometry of $\\sqrt{s_{NN}} = 130$ GeV Au+Au Collisions at RHIC

    OpenAIRE

    STAR Collaboration; Adler, C.

    2001-01-01

    Two-pion correlation functions in Au+Au collisions at $\\sqrt{s_{NN}} = 130$ GeV have been measured by the STAR (Solenoidal Tracker at RHIC) detector. The source size extracted by fitting the correlations grows with event multiplicity and decreases with transverse momentum. Anomalously large sizes or emission durations, which have been suggested as signals of quark-gluon plasma formation and rehadronization, are not observed. The HBT parameters display a weak energy dependence over a broad ran...

  4. Quest for toroidal freeze-out configuration in the central 197Au + 197Au collisions at 23 AMeV

    Directory of Open Access Journals (Sweden)

    Najman R.

    2015-01-01

    Full Text Available We present the results of the experiment performed by the CHIMERA collaboration with the 4π CHIMERA array, for the system 197Au+197Au at 23 AMeV. The experimental data are compared with ETNA and QMD model predictions. Efficiency factor is used as an indication of the formation of an exotic freeze-out configuration. Comparison between experimental data and model predictions may indicate the formation of flat/toroidal nuclear systems.

  5. Facile Synthesis of Au Nanoparticles Embedded in an Ultrathin Hollow Graphene Nanoshell with Robust Catalytic Performance.

    Science.gov (United States)

    Liu, Hongyang; Wang, Jia; Feng, Zhenbao; Lin, Yangming; Zhang, Liyun; Su, Dangsheng

    2015-10-01

    Au nanoparticles (NPs) uniformly embedded into an ultrathin hollow graphene nanoshell (Au@HGN) are synthesized using a facile template-based procedure. The obtained Au@HGN catalyst exhibits robust and stable catalytic performance in the reduction of 4-nitrophenol to 4-aminophenol, compared with that of traditional Au/TiO2 and previously reported Au- and Ag-based catalysts. PMID:26280245

  6. Effect of Au nano-particle aggregation on the deactivation of the AuCl3/AC catalyst for acetylene hydrochlorination.

    Science.gov (United States)

    Dai, Bin; Wang, Qinqin; Yu, Feng; Zhu, Mingyuan

    2015-01-01

    A detailed study of the valence state and distribution of the AuCl3/AC catalyst during the acetylene hydrochlorination deactivation process is described and discussed. Temperature-programmed reduction and X-ray photoelectron spectral analysis indicate that the active Au(3+) reduction to metallic Au(0) is one reason for the deactivation of AuCl3/AC catalyst. Transmission electron microscopy characterization demonstrated that the particle size of Au nano-particles increases with increasing reaction time. The results indicated that metallic Au(0) exhibits considerable catalytic activity and that Au nano-particle aggregation may be another reason for the AuCl3/AC catalytic activity in acetylene hydrochlorination. PMID:25994222

  7. Jet-Hadron Correlations in sqrt{s_{NN}} = 200 GeV Au+Au and p+p Collisions

    CERN Document Server

    Adamczyk, L; Agakishiev, G; Aggarwal, M M; Ahammed, Z; Alekseev, I; Alford, J; Anson, C D; Aparin, A; Arkhipkin, D; Aschenauer, E; Averichev, G S; Balewski, J; Banerjee, A; Barnovska, Z; Beavis, D R; Bellwied, R; Betancourt, M J; Betts, R R; Bhasin, A; Bhati, A K; Bhattarai,; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Bordyuzhin, I G; Borowski, W; Bouchet, J; Brandin, A V; Brovko, S G; Bruna, E; Bültmann, S; Bunzarov, I; Burton, T P; Butterworth, J; Caines, H; Sánchez, M Calderón de la Barca; Cebra, D; Cendejas, R; Cervantes, M C; Chaloupka, P; Chang, Z; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, J Y; Chen, L; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Chung, P; Chwastowski, J; Codrington, M J M; Corliss, R; Cramer, J G; Crawford, H J; Cui, X; Das, S; Leyva, A Davila; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; de Souza, R Derradi; Dhamija, S; di Ruzza, B; Didenko, L; Dilks,; Ding, F; Dion, A; Djawotho, P; Dong, X; Drachenberg, J L; Draper, J E; Du, C M; Dunkelberger, L E; Dunlop, J C; Efimov, L G; Elnimr, M; Engelage, J; Engle, K S; Eppley, G; Eun, L; Evdokimov, O; Fatemi, R; Fazio, S; Fedorisin, J; Fersch, R G; Filip, P; Finch, E; Fisyak, Y; Flores, C E; Gagliardi, C A; Gangadharan, D R; Garand, D; Geurts, F; Gibson, A; Gliske, S; Grebenyuk, O G; Grosnick, D; Guo, Y; Gupta, A; Gupta, S; Guryn, W; Haag, B; Hajkova, O; Hamed, A; Han, L-X; Haque, R; Harris, J W; Hays-Wehle, J P; Heppelmann, S; Hirsch, A; Hoffmann, G W; Hofman, D J; Horvat, S; Huang, B; Huang, H Z; Huck, P; Humanic, T J; Igo, G; Jacobs, W W; Jena, C; Judd, E G; Kabana, S; Kang, K; Kauder, K; Ke, H W; Keane, D; Kechechyan, A; Kesich, A; Kikola, D P; Kiryluk, J; Kisel, I; Kisiel, A; Koetke, D D; Kollegger, T; Konzer, J; Koralt, I; Korsch, W; Kotchenda, L; Kravtsov, P; Krueger, K; Kulakov, I; Kumar, L; Kycia, R A; Lamont, M A C; Landgraf, J M; Landry, K D; LaPointe, S; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; Leight, W; LeVine, M J; Li, C; Li, W; Li, X; Li, Y; Li, Z M; Lima, L M; Lisa, M A; Liu, F; Ljubicic, T; Llope, W J; Longacre, R S; Luo, X; Ma, G L; Ma, Y G; Don, D M M D Madagodagettige; Mahapatra, D P; Majka, R; Margetis, S; Markert, C; Masui, H; Matis, H S; McDonald, D; McShane, T S; Mioduszewski, S; Mitrovski, M K; Mohammed, Y; Mohanty, B; Mondal, M M; Munhoz, M G; Mustafa, M K; Naglis, M; Nandi, B K; Nasim, Md; Nayak, T K; Nelson, J M; Nogach, L V; Novak, J; Odyniec, G; Ogawa, A; Oh, K; Ohlson, A; Okorokov, V; Oldag, E W; Oliveira, R A N; Olson, D; Pachr, M; Page, B S; Pal, S K; Pan, Y X; Pandit, Y; Panebratsev, Y; Pawlak, T; Pawlik, B; Pei, H; Perkins, C; Peryt, W; Pile, P; Planinic, M; Pluta, J; Plyku, D; Poljak, N; Porter, J; Poskanzer, A M; Powell, C B; Pruneau, C; Pruthi, N K; Przybycien, M; Pujahari, P R; Putschke, J; Qiu, H; Ramachandran, S; Raniwala, R; Raniwala, S; Ray, R L; Riley, C K; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Ross, J F; Roy, A; Ruan, L; Rusnak, J; Sahoo, N R; Sahu, P K; Sakrejda, I; Salur, S; Sandacz, A; Sandweiss, J; Sangaline, E; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schmidke, B; Schmitz, N; Schuster, T R; Seger, J; Seyboth, P; Shah, N; Shahaliev, E; Shao, M; Sharma, B; Sharma, M; Shen, W Q; Shi, S S; Shou, Q Y; Sichtermann, E P; Singaraju, R N; Skoby, M J; Smirnov, D; Smirnov, N; Solanki, D; Sorensen, P; deSouza, U G; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stevens, J R; Stock, R; Strikhanov, M; Stringfellow, B; Suaide, A A P; Suarez, M C; Sumbera, M; Sun, X M; Sun, Y; Sun, Z; Surrow, B; Svirida, D N; Symons, T J M; de Toledo, A Szanto; Takahashi, J; Tang, A H; Tang, Z; Tarini, L H; Tarnowsky, T; Thomas, J H; Timmins, A R; Tlusty, D; Tokarev, M; Trentalange, S; Tribble, R E; Tribedy, P; Trzeciak, B A; Tsai, O D; Turnau, J; Ullrich, T; Underwood, D G; Van Buren, G; van Nieuwenhuizen, G; Vanfossen,, J A; Varma, R; Vasconcelos, G M S; Vertesi, R; Videbæk, F; Viyogi, Y P; Vokal, S; Voloshin, S A; Vossen, A; Wada, M; Walker, M; Wang, F; Wang, G; Wang, H; Wang, J S; Wang, Q; Wang, X L; Wang, Y; Webb, G; Webb, J C; Westfall, G D; Wieman, H; Wissink, S W; Witt, R; Wu, Y F; Xiao, Z; Xie, W; Xin, K; Xu, H; Xu, N; Xu, Q H; Xu, W; Xu, Y; Xu, Z; Yan,; Yang, C; Yang, Y; Yepes, P; Yi, L; Yip, K; Yoo, I-K; Zawisza, Y; Zbroszczyk, H; Zha, W; Zhang, J B; Zhang, S; Zhang, X P; Zhang, Y; Zhang, Z P; Zhao, F; Zhao, J; Zhong, C; Zhu, X; Zhu, Y H; Zoulkarneeva, Y; Zyzak, M

    2013-01-01

    Azimuthal angular correlations of charged hadrons with respect to the axis of a reconstructed (trigger) jet in Au+Au and p+p collisions at $\\sqrt{s_{NN}} = 200$ GeV in STAR are presented. The trigger jet population in Au+Au collisions is biased towards jets that have not interacted with the medium, allowing easier matching of jet energies between Au+Au and p+p collisions while enhancing medium effects on the recoil jet. The associated hadron yield of the recoil jet is significantly suppressed at high transverse momentum ($p_{T}^{assoc}$) and enhanced at low $p_{T}^{assoc}$ in Au+Au collisions, which is indicative of medium-induced parton energy loss in ultrarelativistic heavy-ion collisions.

  8. Identified hadron transverse momentum spectra in Au+Au collisions at sNN=62.4 GeV

    Science.gov (United States)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Halliwell, C.; Hamblen, J.; Hauer, M.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Seals, H.; Sedykh, I.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; Nieuwenhuizen, G. J. Van; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wysłouch, B.

    2007-02-01

    Transverse momentum spectra of pions, kaons, protons, and antiprotons from Au+Au collisions at sNN = 62.4 GeV have been measured by the PHOBOS experiment at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. The identification of particles relies on three different methods: low momentum particles stopping in the first detector layers; the specific energy loss (dE/dx) in the silicon spectrometer, and time-of-flight measurement. These methods cover the transverse momentum ranges 0.03 0.2, 0.2 1.0, and 0.5 3.0 GeV/c, respectively. Baryons are found to have substantially harder transverse momentum spectra than mesons. The pT region in which the proton to pion ratio reaches unity in central Au+Au collisions at sNN = 62.4 GeV fits into a smooth trend as a function of collision energy. At low transverse mass, the spectra of various species exhibit a significant deviation from transverse mass scaling. The observed particle yields at very low pT are comparable to extrapolations from higher pT for kaons, protons and antiprotons. By comparing our results to Au+Au collisions at sNN = 200 GeV, we conclude that the net proton yield at midrapidity is proportional to the number of participant nucleons in the collision.

  9. Heterojunction metal-oxide-metal Au-Fe3O4-Au single nanowire device for spintronics

    International Nuclear Information System (INIS)

    In this report, we present the synthesis of heterojunction magnetite nanowires in alumina template and describe magnetic and electrical properties from a single nanowire device for spintronics applications. Heterojunction Au-Fe-Au nanowire arrays were electrodeposited in porous aluminum oxide templates, and an extensive and controlled heat treatment process converted Fe segment to nanocrystalline cubic magnetite phase with well-defined Au-Fe3O4 interfaces as confirmed by the transmission electron microscopy. Magnetic measurements revealed Verwey transition shoulder around 120 K and a room temperature coercive field of 90 Oe. Current–voltage (I-V) characteristics of a single Au-Fe3O4-Au nanowire have exhibited Ohmic behavior. Anomalous positive magnetoresistance of about 0.5% is observed on a single nanowire, which is attributed to the high spin polarization in nanowire device with pure Fe3O4 phase and nanocontact barrier. This work demonstrates the ability to preserve the pristine Fe3O4 and well defined electrode contact metal (Au)–magnetite interface, which helps in attaining high spin polarized current

  10. Heterojunction metal-oxide-metal Au-Fe{sub 3}O{sub 4}-Au single nanowire device for spintronics

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, K. M., E-mail: mrkongara@boisestate.edu; Punnoose, Alex; Hanna, Charles [Department of Physics, Boise State University, Boise, Idaho 83725 (United States); Padture, Nitin P. [School of Engineering, Brown University, Providence, Rhode Island 02912 (United States)

    2015-05-07

    In this report, we present the synthesis of heterojunction magnetite nanowires in alumina template and describe magnetic and electrical properties from a single nanowire device for spintronics applications. Heterojunction Au-Fe-Au nanowire arrays were electrodeposited in porous aluminum oxide templates, and an extensive and controlled heat treatment process converted Fe segment to nanocrystalline cubic magnetite phase with well-defined Au-Fe{sub 3}O{sub 4} interfaces as confirmed by the transmission electron microscopy. Magnetic measurements revealed Verwey transition shoulder around 120 K and a room temperature coercive field of 90 Oe. Current–voltage (I-V) characteristics of a single Au-Fe{sub 3}O{sub 4}-Au nanowire have exhibited Ohmic behavior. Anomalous positive magnetoresistance of about 0.5% is observed on a single nanowire, which is attributed to the high spin polarization in nanowire device with pure Fe{sub 3}O{sub 4} phase and nanocontact barrier. This work demonstrates the ability to preserve the pristine Fe{sub 3}O{sub 4} and well defined electrode contact metal (Au)–magnetite interface, which helps in attaining high spin polarized current.

  11. Related power-law growth of particle multiplicities near midrapidity in central Au+Au collisions and in pbar(p)-p collisions

    International Nuclear Information System (INIS)

    A simple power-law growth of charged-particle multiplicities near midrapidity in central Au+Au collisions at √sNN = 56 and 130 GeV, recently measured at RHIC, is derived. We give predictions for the central particle densities up to √sNN = 1800 GeV. A strong growth of the Au+Au densities above those for pbar(p)-p collisions is predicted

  12. Transverse-energy distributions at midrapidity in $p$$+$$p$, $d$$+$Au, and Au$+$Au collisions at $\\sqrt{s_{_{NN}}}=62.4$--200~GeV and implications for particle-production models

    OpenAIRE

    Adler, S. S.; Afanasiev, S.; Aidala, C.; Ajitanand, N. N.; Akiba, Y; Al-Jamel, A.; Alexander, J.; Aoki, K.; Aphecetche, L.; Armendariz, R.; Aronson, S. H.; Averbeck, R.; Awes, T. C.; Azmoun, B.; Babintsev, V.

    2013-01-01

    Measurements of the midrapidity transverse energy distribution, $d\\Et/d\\eta$, are presented for $p$$+$$p$, $d$$+$Au, and Au$+$Au collisions at $\\sqrt{s_{_{NN}}}=200$ GeV and additionally for Au$+$Au collisions at $\\sqrt{s_{_{NN}}}=62.4$ and 130 GeV. The $d\\Et/d\\eta$ distributions are first compared with the number of nucleon participants $N_{\\rm part}$, number of binary collisions $N_{\\rm coll}$, and number of constituent-quark participants $N_{qp}$ calculated from a Glauber model based on th...

  13. Usefulness and performance of the Au-195m generator

    International Nuclear Information System (INIS)

    Clinical usefulness of the Au-195m generator has been confirmed in several countries. The principal advantages are the reduction of patient radiation exposure and the possibilities of multiple, background-free, sequential evaluations of left and right ventricular function, both at rest and during exercise. Gold-195m has a half-life of 30.5 sec and is generator-produced from Hg-195m (T 1/2 = 41.6 hr). Mercury-195m is cyclotron produced from an Au-197 target by the (p,3n) reaction during bombardment with 28.5 Mev protons. Mercury-195m decays by electron capture 45.8% of the time to Au-195m; 262 keV gammas are used for imaging. Breakthrough of the parent Hg-195m has two negative effects, since it increases patient exposure and degrades image quality due to high energy gammas. The breakthrough is 0.75 + or - 0.09 μCi of Hg/mCi of Au-195m. The reproducibility of elution has a coefficient of variation of 2.5 + or - 0.3%. The eluates were sterile and pyrogen-free. The yield of the generator is 20-30 mCi of Au-195m from 155 mCi of Hg-195m generator. The short half-life of Au-195m offers the potential of frequent background-free determinations of left ventricular function which offer additional use for evaluation of left ventricular ejection fraction and volume indices. Rapid acquisition of data from varying levels of exercise, frequent assessment of pharmacologic and physiologic interventions and simultaneous acquisitions of data using more than one radionuclide become readily feasible with agents such as Au-195m

  14. Spin reorientation transition in Co/Au multilayers

    International Nuclear Information System (INIS)

    We report a study about the spin reorientation transition (SRT) from perpendicular easy axis to in-plane easy axis of magnetization in Co/Au multilayers. A series of multilayers of Si/Au(100 Å)/{[Co(tCo)/Au(20 Å)]20}/Au(50 Å) family were studied, with Co layer thickness varying between 6 Å to 30 Å. The thickness of the Au layer was chosen large enough in order to minimize the interlayer exchange coupling between Co layers. In such thick Au-layer samples the magnetic properties are mainly the result of competition between interlayer magnetostatic coupling due to stray field, perpendicular magnetic anisotropy and shape anisotropy. The effective anisotropy constant Keff and the second order anisotropy K2 were deduced from the fit of the resonant magnetic field obtained from out of plane dependence Ferromagnetic Resonance (FMR) experiments. To study the SRT, we have plotted the phase diagram between Keff and K2. The results show that SRT occurs through the metastable region with K2 ≤ −½ Keff, (Keff > 0). It is interesting to note that FMR shows the coexistence of two modes with different anisotropy for small Co thickness, while for thick Co layers the modes have the same anisotropy. Moreover, in thick Co layer samples, volume and surface spin wave resonance (SWR) modes were also excited by the microwave field, around the perpendicular FMR geometry, giving a clear evidence of a magnetic coupling between the Co layers. - Highlights: • Co/Au multilayers with varying Co layer thickness are prepared by DC-magnetron sputtering. • The spin reorientation transition (SRT) and flipping of magnetic moment are studied. • Effective anisotropy constant (K) and 2nd order anisotropy constant (K2) are calculated. • K Vs K2 plot showed that SRT occurs through the metastable region with K2 ≤ −½ K, (K > 0). • Ferromagnetic Resonance spectra showed the coexistence of two resonance modes

  15. Growth and size distribution of Au nanoparticles in annealed Au/TiO2 thin films

    International Nuclear Information System (INIS)

    Nanocomposites consisting of noble metal nanoparticles (NPs) embedded in TiO2 thin films are of great interest for applications in optoelectronics, photocatalysis and solar-cells for which the plasmonic properties of the metal NPs play a major role. This work investigates the first stages of the formation of gold NPs by thermal annealing of Au-doped TiO2 thin films grown by magnetron sputtering. A low concentration of gold in the films is considered (5 at.%) in order to study the first stages of the formation of the NPs. Raman spectroscopy is used to follow the crystallization of TiO2 when increasing the annealing temperature. In addition, low-frequency Raman scattering (LFRS) is used to investigate the formation of gold NPs and to determine their size. Resonant LFRS measurements obtained by using a laser wavelength matching the surface plasmon resonance of the metallic NPs significantly enhances the Raman peak intensity enabling to focus on the first stages of the NPs formation. A double size distribution is observed at Ta = 800 °C calling for additional investigations by transmission electron microscopy (TEM). TEM observations reveal an inhomogeneous in-depth size distribution of gold NPs. The annealed films are structured in two sublayers with bigger NPs at the bottom and smaller NPs at the top. At Ta = 800 °C, a double size distribution is confirmed near the surface. A mechanism is proposed to explain the formation of the sublayers. The modification of the diffusion of gold atoms by stresses in the film near the substrate is assumed to be responsible for the observed two layers structure. - Highlights: • Gold-doped TiO2 thin films were grown by magnetron sputtering. • The first stages of the formation of Au nanoparticles after annealing are studied. • Au nanoparticles and crystallized TiO2 are observed above 400 °C. • The size distribution of the gold nanoparticles is complex and depth-dependent

  16. Efficient H2 production over Au/graphene/TiO2 induced by surface plasmon resonance of Au and band-gap excitation of TiO2

    International Nuclear Information System (INIS)

    Highlights: • Both surface plasmon resonance and band-gap excitation were used for H2 production. • Au/Gr/TiO2 composite photocatalyst was synthesized. • Au/Gr/TiO2 exhibited enhancement of light absorption and charge separation. • H2 production rate of Au/Gr/TiO2 was about 2 times as high as that of Au/TiO2. - Abstract: H2 production over Au/Gr/TiO2 composite photocatalyst induced by surface plasmon resonance of Au and band-gap excitation of TiO2 using graphene (Gr) as an electron acceptor has been investigated. Electron paramagnetic resonance study indicated that, in this composite, Gr collected electrons not only from Au with surface plasmon resonance but also from TiO2 with band-gap excitation. Surface photovoltage and UV–vis absorption measurements revealed that compared with Au/TiO2, Au/Gr/TiO2 displayed more effective photogenerated charge separation and higher optical absorption. Benefiting from these advantages, the H2 production rate of Au/Gr/TiO2 composite with Gr content of 1.0 wt% and Au content of 2.0 wt% was about 2 times as high as that of Au/TiO2. This work represents an important step toward the efficient application of both surface plasmon resonance and band-gap excitation on the way to converting solar light into chemical energy

  17. Structure and Properties of Sr 2Au 3In 4 and Eu 2Au 3In 4

    Science.gov (United States)

    Hoffmann, Rolf-Dieter; Pöttgen, Rainer; Rosenhahn, Carsten; Mosel, Bernd D.; Künnen, Bernd; Kotzyba, Gunter

    1999-06-01

    Sr2Au3In4 was synthesized by reacting the elements in glassy carbon crucibles under an argon atmosphere in a high-frequency furnace. Eu2Au3In4 was obtained in the same way but starting with EuAuIn as a precursor and admixing indium and gold. Both compounds were investigated by X-ray diffraction on powders and single crystals: anti-Hf2Co4P3 type, Poverline62m, a=1501.6(9) pm, c=457.9(2) pm, wR2=0.0734, 1030 F2 values, 45 variables for Sr2Au2.85In4.15 and a=1489.7(3) pm, c= 454.90(7) pm, wR2=0.1222, 1051 F2 values, 45 variables for Eu2Au3In4. One gold site in the strontium compound shows a mixed occupancy with indium atoms indicating a small homogeneity range according to Sr2Au3-xIn4+x. Striking structural motifs of Sr2Au3In4 and Eu2Au3In4 are gold-centered trigonal prisms formed by the strontium (europium) and indium atoms. All gold atoms have coordination number 9 in the form of tricapped trigonal prisms. The indium atoms in Sr2Au3In4 and Eu2Au3In4 occupy the cobalt positions of the Hf2Co4P3 type and the more electronegative gold atoms take the phosphorus positions, indicating that Sr2Au3In4 and Eu2Au3In4 may be considered as ternary aurides. The gold and indium atoms form three-dimensional [Au3In4]4- polyanions in which the divalent strontium and europium atoms occupy distorted hexagonal tubes. Magnetic susceptibility measurements of Eu2Au3In4 show paramagnetic behavior above 50 K with an experimental magnetic moment of 7.88(5) μB/Eu indicating Eu2+. Antiferromagnetic ordering is detected at 9.5(5) K at low external fields. A metamagnetic transition is observed at 2 K at a critical field of 0.5(2) T. The experimental saturation moment at 2 K and 5.5 T is 5.95(5) μB/Eu. Electrical conductivity investigations exhibit metallic behavior with a room temperature value of 75±10 μΩcm for the specific resistivity. 151Eu Mössbauer spectroscopic measurements show a broadened line with an isomer shift of -10.5(5) mm/s at 78 K in accordance with several sites of divalent

  18. Effects of stretching and compression on conducting properties of an Au-alkanedithiol-Au molecular junction

    Science.gov (United States)

    Xie, Fang; Zhang, Xiao-Jiao; Yu, Ji-Hai; Xu, Hua; Chu, Yu-Fang; Fan, Zhi-Qiang

    2016-03-01

    We have studied the effects of stretching and compression on the electronic properties of 7-alkanedithiol covalently linked to two Au electrodes. Results show a progressive increase in conductivity upon molecule compression and decrease with molecule stretching. The notable conductance increase at high compression is attributed to a significant modification of HOMO and LUMO orbitals of the junction, which enhances electron delocalization and promotes tunneling across the junction. More important, the current switching ratios between the various stages of compressed/extended geometries almost maintain the constant values on the bias region from 0 V to 2 V. In other word, the mechanically-induced conductance enhancement and weakening are stable within a large bias voltage range.

  19. Chapitre 5. Robots au Japon : le futur se conjugue au présent

    OpenAIRE

    Barral, Étienne

    2016-01-01

    2015... Les analystes japonais aiment bien projeter leurs lecteurs dans le futur. En 2015 donc, selon le Rapport intérimaire du comité stratégique en robotique du ministère japonais de l’Économie, du Commerce et de l’Industrie, le marché de la robotique au Japon représentera 1,1 billion de yens (7,8 milliards d’euros). Une somme, déjà astronomique, à rapprocher de la production japonaise des ordinateurs personnels en 2005 : 1,6 billion de yens (10,8 milliards d’euros). Dans moins d’une décenn...

  20. Structure investigation of organic molecules on Au(111) surfaces; Strukturuntersuchung organischer Molekuele auf Au(111)-Oberflaechen

    Energy Technology Data Exchange (ETDEWEB)

    Kazempoor, Michel

    2009-02-02

    The present work covers two topics namely the coadsorption of formic acid and water on Au(111) and the structure of biphenylalkanthiole SAMs on Au(111) surfaces. The coadsorption of formic acid and water on Au(111) surfaces has been investigated by means of vibrational and photoelectron spectroscopy (HREELS, XPS). Formic acid adsorbs at 90 K molecularly with vibrational modes characteristic for flat lying zig-zag chains in the mono- and multilayer regime, like in solid formic acid. The structure of the flat lying formic acid chains was determined by low energy electron diffraction (LEED) as a (2r3 x r19) unit cell. Annealing results in a complete desorption at 190 K. Sequential adsorption of formic acid and water at 90 K shows no significant chemical interaction. Upon annealing the coadsorbed layer to 140 K a hydrogenbonded cyclic complex of formic acid with one water molecule could be identified using isotopically labelled adsorbates. Upon further annealing this complex decomposes leaving molecularly adsorbed formic acid on the surface at 160 K, accompanied by a proton exchange between formic acid and water. The influence of the alkane spacer chain length on the structure of biphenylalkanethiols on Au(111) surfaces was investigated as well. A systematic study was done on BPn-SAMs deposited from the gas phase. For every chain length a structure was found by LEED. Furthermore the influence of temperature on the structure was investigated in the range from room temperature up to about 400 K. To obviate influences from different preparation methods BP3 and BP4 was deposited from gas phase and from solution. No LEED spots were observed on BP4 SAMs deposited from solution. For BP3 an influence of the preparation could be excluded. For all BPn-SAMs a good agreement between LEED and STM data's was found. Nevertheless different unit cells were determined by LEED and STM consistent structures could be suggested considering the unit cell size given by LEED and the

  1. Intoxications au dextropropoxyphène et au tramadol: bilan d'un an de recueil

    OpenAIRE

    Cohen, Sabine; Manchon, Monique; Artur, Michèle; Capolaghi, Bernard; Denooz, Raphael; Houdret, Nicole; Jourdil, Nicole; Kergueris, Marie-France; Lamiable, Denis; Mousla, Mustapha; Sadeg, Nouredine; Turcant, Alain

    2006-01-01

    La prescription de plus en plus fréquente du dextropropoxyphène (DP) et du tramadol, deux antalgiques opioïdes, a conduit les membres du groupe de travail "Toxicologie hospitalière" de la Société Française de Toxicologie Analytique (SFTA) à étudier leur toxicité clinique observée. L'étude a consisté en l'analyse des cas où l'une ou l'autre de ces molécules a été identifiée au décours d'un screening toxicologique réalisé durant l'année 2004 dans les laboratoires hospitaliers des membres de ce ...

  2. Phenomenological magnetic modeling of Au:Fe:Au nano-onions

    Science.gov (United States)

    Wiggins, J.; Carpenter, Everett E.; O'Connor, Charles J.

    2000-05-01

    A new type of materials, the nano-onions, has been shown to exhibit GMR. These nanostructured composites consist of a nonmagnetic core coated with a thin layer of a bulk ferromagnet with a passivating nonmagnetic surface layer. The nano-onion investigated had a 3 nm Au core, a 1 nm Fe layer, and a 2 nm Au coating; all values correspond to the radius. The materials were manufactured using a sequential reverse micelle technique, detailed elsewhere. The sample preparation method produces a powder sample was cold pressed into a pellet. Magnetic investigation of the sample indicated that the material was superparamagnetic with a blocking temperature of 52 K for particles approximately 8 nm in diameter. At 10 K, the coercivity was 420 Oe, indicating a large degree of order. The GMR was measured over the entire temperature range available. At 10 K, in 5 T, a 1% MR was observed. The GMR was modeled using a simple phenomenological magnetic model initially used to study GMR granular thin films. To more accurately match the physical parameters of reverse micelles, the conventional log-normal particle size distribution was replaced with a normal distribution. The model suggested that the system consisted of an ensemble of 1.3 nm particles with a standard deviation of 0.07. The model does not detect the entire 8 nm diam, rather it detects the individual walls of the shell. In this context, it has shown that a simple phenomenological model can accurately predict the magnetic and electronic behavior of nano-onions.

  3. Massignon and Zionism Massignon face au sionisme

    Directory of Open Access Journals (Sweden)

    Agathe Mayeres

    2010-03-01

    sioniste qui, pour lui, est avant tout un problème de politique orientale.Sous l’influence de Aaron Aaronsohn, l’islamologue éprouve d’abord pour les pionniers d’Eretz Israel, au regard de leurs réalisations agricoles, une sympathie enthousiaste qui lui fait souhaiter la réussite de l’établissement du Foyer national juif en Palestine. Son engagement l’incite notamment à rédiger, conjointement avec Maritain, un « rapport sur le sionisme », adressé à Pie XI en 1925, dans le but d’obtenir du Saint-Siège un soutien pour les Juifs convertis au catholicisme qui souhaiteraient participer à l’œuvre commune de la résurrection d’Israël. Cependant, les procédés « colonisateurs » et l’athéisme affiché de nombreux dirigeants sionistes, allant à l’encontre des convictions religieuses des Arabes autochtones chrétiens et musulmans, provoquent peu à peu chez Massignon un revirement total qui lui dicte à l’égard des Juifs des « propos excessifs ». Massignon considère qu’en Terre Sainte, il est impossible de séparer le temporel du spirituel et que les faits doivent être lus à la lumière des événements de l’histoire religieuse qui s’y sont déroulés depuis Abraham, « premier héros de l’hospitalité ».La prise de conscience de la pureté de Marie lui paraît la condition nécessaire à une reconnaissance juive dans l’esprit du Patriarche, bien plus, un préalable à toute paix. Massignon voit dans l’Immaculée Conception le « signe marial » de ralliement des diverses confessions de la famille abrahamique.

  4. Massignon face au sionisme Massignon and Zionism

    Directory of Open Access Journals (Sweden)

    Agathe Mayeres

    2010-03-01

    Full Text Available En 1916, Louis Massignon participe aux négociations franco-britanniques qui envisagent, dans la perspective de la capitulation probable des empires centraux, le futur partage de l’Empire ottoman. Dans ce contexte, Massignon cherche à se situer face la question sioniste qui, pour lui, est avant tout un problème de politique orientale.Sous l’influence d'Aaron Aaronsohn, l’islamologue éprouve d’abord pour les pionniers d’Eretz Israel, au regard de leurs réalisations agricoles, une sympathie enthousiaste qui lui fait souhaiter la réussite de l’établissement du Foyer national juif en Palestine. Son engagement l’incite notamment à rédiger, conjointement avec Maritain, un « rapport sur le sionisme », adressé à Pie XI en 1925, dans le but d’obtenir du Saint-Siège un soutien pour les Juifs convertis au catholicisme qui souhaiteraient participer à l’œuvre commune de la résurrection d’Israël. Cependant, les procédés « colonisateurs » et l’athéisme affiché de nombreux dirigeants sionistes, allant à l’encontre des convictions religieuses des Arabes autochtones chrétiens et musulmans, provoquent peu à peu chez Massignon un revirement total qui lui dicte à l’égard des Juifs des « propos excessifs ». Massignon considère qu’en Terre Sainte, il est impossible de séparer le temporel du spirituel et que les faits doivent être lus à la lumière des événements de l’histoire religieuse qui s’y sont déroulés depuis Abraham, « premier héros de l’hospitalité ».La prise de conscience de la pureté de Marie lui paraît la condition nécessaire à une reconnaissance juive dans l’esprit du Patriarche, bien plus, un préalable à toute paix. Massignon voit dans l’Immaculée Conception le « signe marial » de ralliement des diverses confessions de la famille abrahamique.In 1916, facing the probable capitulation of the Central Powers, Louis Massignon participates in French

  5. Relégation au village

    Directory of Open Access Journals (Sweden)

    Nicolas Renahy

    2010-12-01

    Full Text Available Les thèses de l’individualisation des sociétés occidentales, ou de l’exclusion de ceux qui resteraient en marge d’une vaste classe moyenne aux modes de vie homogénéisés, ont sans doute permis de sortir d’une grille de lecture rigide héritée du marxisme. Mais elles résistent aujourd’hui mal aux faits et sont vivement contredites par le renouvellement des études sur les inégalités sociales pensées en termes de stratification. Enquêtant la population ouvrière d’un village industriel de Bourgogne au cours des années 1990, l’auteur a pu mesurer tout autant la force socialisatrice continue du groupe ouvrier sur sa jeunesse que le lent processus de délitement de ses cadres de références, longtemps stabilisés autour d’une mono-industrie métallurgique, provoquant une crise dans la reproduction de ce monde ouvrier. C’est cette crise de reproduction qui est évoquée ici. Dans un premier temps sont explicitées les formes passées de la présence industrielle au village, qui n’a jamais été celle d’un bastion de la grande industrie – la population locale n’est pas structurellement différenciée de celle de son environnement rural immédiat. L’exemple d’une lignée familiale d’artisans montre pour finir l’étroit maillage entre usine et structures sociales plus classiquement rurales, favorisant la constitution d’un capital d’autochtonie, déclinaison populaire du capital social.Relegation to the villageArguments demonstrating the individualisation of western societies, or the exclusion of those who stay on the margins of a vast middle class homogeneous life style, have no doubt allowed the move away from the rigid interpretations inherited from Marxism. However, these arguments resist today in spite of the facts and they are even keenly contradicted by the renewal of stratification studies on social inequalities. Analyzing the working population of an industrial village in Bourgogne during the

  6. Observations of high spin states in {sup 179}Au

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, M.P.; Ahmad, I.; Blumenthal, D.J. [and others

    1995-08-01

    As part of a current study on the properties of the {pi} i{sub 13/2} intruder state in the A = 175-190 region, we conducted an experiment at ATLAS to observe high spin states in {sup 179}Au utilizing the reaction {sup 144}Sm({sup 40}Ar,p4n) at beam energies of 207 MeV and 215 MeV. To aid in the identification of {sup 179}Au, and to filter out the large amount of events from fission by-products, the Fragment Mass Analyzer was utilized in conjunction with ten Compton-suppression germanium detectors. In total, 11 x 10{sup 6} {gamma}-{gamma} and 4 x 10{sup 5} {gamma}-recoil events were collected. By comparing {gamma}-rays in coincidence with an A = 179 recoil mass gate and {gamma}-rays in coincidence with Au K{alpha} and K{beta} X-rays, ten {gamma}-rays were identified as belonging to {sup 179}Au. Based on {gamma}-ray coincidence relationships and on comparisons with neighboring odd-A Au nuclei, we constructed a tentative level scheme and assigned a rotational-like sequence to the {pi} i{sub 13/2} proton configuration.

  7. Exotic high activity surface patterns in PtAu nanoclusters

    KAUST Repository

    Mokkath, Junais Habeeb

    2013-05-09

    The structure and chemical ordering of PtAu nanoclusters of 79, 135, and 201 atoms are studied via a combination of a basin hopping atom-exchange technique (to locate the lowest energy homotops at fixed composition), a symmetry orbit technique (to find the high symmetry isomers), and density functional theory local reoptimization (for determining the most stable homotop). The interatomic interactions between Pt and Au are derived from the empirical Gupta potential. The lowest energy structures show a marked tendency toward PtcoreAushell chemical ordering by enrichment of the more cohesive Pt in the core region and of Au in the shell region. We observe a preferential segregation of Pt atoms to (111) facets and Au atoms to (100) facets of the truncated octahedron cluster motif. Exotic surface patterns are obtained particularly for Pt-rich compositions, where Pt atoms are being surrounded by Au atoms. These surface arrangements boost the catalytic activity by creating a large number of active sites. © 2013 American Chemical Society.

  8. L'APPRENTISSAGE AU CERN - French version only

    CERN Multimedia

    2003-01-01

    APPRENTISSAGES TECHNIQUES FORMATION ET DEVELOPPEMENT HR/TD/AP L'APPRENTISSAGE AU CERN 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). 7 places au total sont ouvertes au recrutement pour les deux professions. L'apprentissage dure 4 ans. Minima requis pour faire acte de candidature : - avoir terminé la scolarité obligatoire - être ressortissant d'un pays membre du CERN (Allemagne, Autriche, Belgique, Bulgarie, Danemark, Espagne, Finlande, France, Grèce, Hongrie, Italie, Norvège, Pays-Bas, Pologne, Portugal, République slovaque, République tchèque, Royaume-Uni, Suède, Suisse) - avoir au moins 15 ans et moins de 21 ans à la date de début de l'apprentissage - avoir un niveau scolaire correspondant à la 9ème générale ou moderne...

  9. Ordered phase formation and diffusion composition path in Cu3Au/Pd couple

    International Nuclear Information System (INIS)

    EDX-TEM technique, IKL-ALCHEMI and Monte Carlo simulation were employed to reveal the relation between diffusion composition path and the ordered structures in Cu3Au/Pd diffusion couple annealed at 573 K. A Cu3Au layer including Pd, a CuAu layer including Pd, a CuPd layer and a Pd layer including Cu existed in sequence between Cu3Au and Pd. The Au concentration increased by up-hill diffusion from the Cu3Au layer to the CuAu layer, whereas Au scarcely diffused from the CuAu into the CuPd layer. The diffusion composition path deviated from the Cu3Au-Pd line in the Cu-Au-Pd Gibbs triangle and exhibited an 'S-shaped' curve through the CuAu and CuPd existence regions. The atomic configurations in the L10-type phase were highly ordered and consistent with the equilibrium state. In the Monte Carlo simulation, diffusion couples were virtually produced. The diffusion composition paths, Fourier power spectra and Warren-Cowley parameters were estimated in this way. The strong ordering interactions of the Cu-Au pair and Cu-Pd pair in the first nearest neighbor and the high activation barrier for migration of Au reproduced experimental results

  10. Study on antibacterial activity of chemically synthesized PANI-Ag-Au nanocomposite

    Science.gov (United States)

    Boomi, Pandi; Prabu, Halliah Gurumallesh; Manisankar, Paramasivam; Ravikumar, Sundaram

    2014-05-01

    Pristine polyaniline (PANI), PANI-Ag, PANI-Au and PANI-Ag-Au nanocomposites have been successfully synthesized by chemical oxidative polymerization method using aniline as monomer, ammonium persulphate as oxidant and metal (Ag, Au and Ag-Au) colloids. UV-Vis analysis exhibited surface Plasmon resonances of Ag, Au, Ag-Au nanoparticles. FT-IR spectra revealed the shift in peak position of N-H stretching. X-ray diffraction (XRD) results confirm the presence of Ag, Au and Au-Ag nanoparticles. HR-TEM images show nanosizes of Ag, Au, Ag-Au and the incorporation of such nanoparticles into the PANI matrix. Pristine PANI, PANI-Ag, PANI-Au and PANI-Ag-Au nanocomposites were tested for antibacterial activity by agar well diffusion method. PANI-Ag-Au nanocomposite exhibited higher antibacterial activity against both gram-positive [Streptococcus sp. (MTCC 890), Staphylococcus sp. (MTCC 96)] and gram-negative bacteria [Escherichia coli (MTCC 1671) and Klebsiella sp. (MTCC 7407)] when compared with PANI-Ag nanocomposite, PANI-Au nanocomposite and pristine PANI. The novelty of this study is the polymer-bimetal synthesis and its antibacterial potential.

  11. Transverse momentum and centrality dependence of high-pt non-photonic electron suppression in Au+Au collisions at $\\sqrt{s_{NN}}$ = 200 GeV

    CERN Document Server

    Abelev, B I; 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; Calderón 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; De Phillips, M; Derevshchikov, 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-Majumdar, 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, Yu; Fu, J; Gagliardi, C A; Gaillard, L; Ganti, M S; Ghazikhanian, V; Ghosh, P; González, J E; Gorbunov, Y G; Gos, H; Grebenyuk, O; Grosnick, D P; Guertin, S M; Guimaraes, K S F F; Guo, Y; Gupta, N; Gutíerrez, 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; 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; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kouchpil, V; Kowalik, K L; Krämer, M; Kravtsov, P; Kravtsov, V I; Krüger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; La Pointe, S; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Lee, C H; Lehocka, S; Le Vine, M J; Li, C; Li, Q; Li, Y; Lin, G; Lin, X; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, J; Liu, L; Liu, Z; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; López-Noriega, M; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, J G; Ma, Y G; Magestro, D; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Melnik, Yu M; Meschanin, A; Miller, M L; Minaev, N G; Mioduszewski, S; Mironov, C; Mischke, A; Mishra, D K; Mitchell, J; Mohanty, B; Molnár, L; Moore, C F; Morozov, D A; Munhoz, M G; Nandi, B K; Nattrass, C; Nayak, T K; Nelson, J M; Netrakanti, P K; Nikitin, V A; Nogach, L V; Nurushev, S B; Odyniec, Grazyna Janina; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Pachr, M; Pal, S K; Panebratsev, Yu A; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevozchikov, V; Perkins, C; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Poljak, N; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M V; Potrebenikova, E V; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rakness, G; Raniwala, R; Raniwala, S; Ray, R L; Razin, S V; Reinnarth, J; Relyea, D; Retière, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M J; Sahoo, R; Salur, S; Sandweiss, J; Sarsour, M; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Schweda, K; Seger, J; Selyuzhenkov, I; Seyboth, P; Shabetai, A; Shahaliev, E; Shao, M; Sharma, M; Shen, W Q; Shimansky, S S; Sichtermann, E P; Simon, F; Singaraju, R N; Smirnov, N; Snellings, R; Sood, G; Sørensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Stock, R; Stolpovsky, A; Strikhanov, M N; Stringfellow, B C; Suaide, A A P; Sugarbaker, E R; Sumbera, M; Sun, Z; Surrow, B; Swanger, M; Symons, T J M; Szanto de Toledo, A; Tai, A; Takahashi, J; Tang, A H; Tarnowsky, T J; Thein, D; Thomas, J H; Timmins, A R; Timoshenko, S; Tokarev, M; Trainor, T A; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; Van der Kolk, N; Van Leeuwen, M; Van der Molen, A M; Varma, R; Vasilevski, I M; Vasilev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Waggoner, W T; Wang, F; Wang, G; Wang, J S; Wang, X L; Wang, Y; Watson, J W; Webb, J C; Westfall, G D; Wetzler, A; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Q H; Xu, Z; Yepes, P; Yoo, I K; Yurevich, V I; Zhan, W; Zhang, H; Zhang, W M; Zhang, Y; Zhang, Z P; Zhao, Y; Zhong, C; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N; Zuo, J X; al, et

    2006-01-01

    The STAR collaboration at RHIC reports measurements of the inclusive yield of non-photonic electrons, which arise dominantly from semi-leptonic decays of heavy flavor mesons, over a broad range of transverse momenta ($1.2 < \\pt < 10$ \\gevc) in \\pp, \\dAu, and \\AuAu collisions at \\sqrtsNN = 200 GeV. The non-photonic electron yield exhibits unexpectedly large suppression in central \\AuAu collisions at high \\pt, suggesting substantial heavy quark energy loss in hot QCD matter. The centrality and \\pt dependences of the suppression provide stringent constraints on theoretical models of suppression.

  12. Atomic and electronic structures of Si(1 1 1)-(√3 x √3)R30°-Au and (6 × 6)-Au surfaces.

    Science.gov (United States)

    Patterson, C H

    2015-12-01

    Si(1 1 1)-Au surfaces with around one monolayer of Au exhibit many ordered structures and structures containing disordered domain walls. Hybrid density functional theory (DFT) calculations presented here reveal the origin of these complex structures and tendency to form domain walls. The conjugate honeycomb chain trimer (CHCT) structure of the [Formula: see text]-Au phase contains Si atoms with non-bonding surface states which can bind Au atoms in pairs in interstices of the CHCT structure and make this surface metallic. Si adatoms adsorbed on the [Formula: see text]-Au surface induce a gapped surface through interaction with the non-bonding states. Adsorption of extra Au atoms in interstitial sites of the [Formula: see text]-Au surface is stabilized by interaction with the non-bonding orbitals and leads to higher coverage ordered structures including the [Formula: see text]-Au phase. Extra Au atoms bound in interstitial sites of the [Formula: see text]-Au surface result in top layer Si atoms with an SiAu4 butterfly wing configuration. The structure of a [Formula: see text]-Au phase, whose in-plane top atomic layer positions were previously determined by an electron holography technique (Grozea et al 1998 Surf. Sci. 418 32), is calculated using total energy minimization. The Patterson function for this structure is calculated and is in good agreement with data from an in-plane x-ray diffraction study (Dornisch et al 1991 Phys. Rev. B 44 11221). Filled and empty state scanning tunneling microscopy (STM) images are calculated for domain walls and the [Formula: see text]-Au structure. The [Formula: see text]-Au phase is 2D chiral and this is evident in computed and actual STM images. [Formula: see text]-Au and domain wall structures contain the SiAu4 motif with a butterfly wing shape. Chemical bonding within the Si-Au top layers of the [Formula: see text]-Au and [Formula: see text]-Au surfaces is analyzed and an explanation for the SiAu4 motif structure is given. PMID

  13. Microstructural dependence on middle eigenvalue in Ti–Ni–Au

    International Nuclear Information System (INIS)

    Highlights: • Lamellar twin density is reduced when λ2 = 1 is approached. • Compound twins are replaced by Type I twins when Au content increases. • Local lattice parameters measured using internal reference of Au particles. -- Abstract: The microstructure of various compounds of the Ti–Ni–Au alloy system is investigated by transmission electron microscopy in relation with changing lattice parameters improving the compatibility conditions between austenite and martensite expressed by the λ2 = 1 equation based on the Geometrically NonLinear Theory of Martensite (GNLTM). Although local differences in microstructure are observed, when increasing the gold content compound twins are replaced by Type I twins, while twinned lamellar structures are replaced by untwinned plates and self-accommodating structures when λ2 = 1 is approached, all confirming the predictions of the GNLTM

  14. Fermi surfaces of surface states on Si(111)-Ag, Au

    Science.gov (United States)

    Crain, J. N.; Altmann, K. N.; Bromberger, C.; Himpsel, F. J.

    2002-11-01

    Metallic surface states on semiconducting substrates provide an opportunity to study low-dimensional electrons decoupled from the bulk. Angle resolved photoemission is used to determine the Fermi surface, group velocity, and effective mass for surface states on Si(111)(3)×(3)-Ag, Si(111)(3)×(3)-Au, and Si(111)(21)×(21)-(Ag+Au). For Si(111)(3)×(3)-Ag the Fermi surface consists of small electron pockets populated by electrons from a few % excess Ag. For Si(111)(21)×(21)-(Ag+Au) the pockets increase their size corresponding to a filling by three electrons per unit cell. The (21)×(21) superlattice leads to an intricate surface umklapp pattern and to minigaps of 110 meV, giving an interaction potential of 55 meV for the (21)×(21) superlattice.

  15. Fabrication of Au/Ni Multilayered Nanowires by Electrochemical Deposition

    International Nuclear Information System (INIS)

    Electrochemical deposition of Au/Ni multilayered nanowires using template-assisted growth technique from electrolyte containing nickel chloride and gold solution was studied in details. 60 μm-thick anodized aluminum oxide (AAO) with pore diameter of 200 nm was used as the template. Chronopotentiometry experiments were first carried out to determine the deposition conditions and the growth rate of individual Au and Ni layers. Scanning electron microscopy results revealed that the pore channels of AAO were completely filled with Au/Ni multisegmented nanowires. By selectively removing the Ni segments in the multilayered nanowires, high-yield of pure gold nanorods were obtained. Detailed studies on the nanostructures obtained were carried out using various microscopy and probe-based techniques for structural, morphological and chemical characterizations.

  16. Des poussins au poivre, volailles aux tables épiques

    OpenAIRE

    Naudet, Valérie

    2014-01-01

    Tout le ciel cette nuit proclameL’hécatombe des rossignolsAragon, Les Poètes Lorsque le héros épique lève les yeux vers l’azur profond du zénith, les seules ailes qu’il y puisse voir sont celles des anges venus à sa rencontre. De vol d’oiseaux, point. Lorsque le héros épique s’éveille, au matin de la bataille, c’est au son des messes chantées et au cliquetis des armes que l’on saisit. De chant d’oiseaux, point. Le fracas des armes et la fureur des