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Sample records for brookhaven ags

  1. Brookhaven highlights

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, M.S.; Cohen, A.; Greenberg, D.; Seubert, L. (eds.)

    1992-01-01

    This publication provides a broad overview of the research programs and efforts being conducted, built, designed, and planned at Brookhaven National Laboratory. This work covers a broad range of scientific disciplines. Major facilities include the Alternating Gradient Synchrotron (AGS), with its newly completed booster, the National Synchrotron Light Source (NSLS), the High Flux Beam Reactor (HFBR), and the RHIC, which is under construction. Departments within the laboratory include the AGS department, accelerator development, physics, chemistry, biology, NSLS, medical, nuclear energy, and interdepartmental research efforts. Research ranges from the pure sciences, in nuclear physics and high energy physics as one example, to environmental work in applied science to study climatic effects, from efforts in biology which are a component of the human genome project to the study, production, and characterization of new materials. The paper provides an overview of the laboratory operations during 1992, including staffing, research, honors, funding, and general laboratory plans for the future.

  2. Longitudinal Flow from 2-8 AGeV Au+Au Collisions at the Brookhaven AGS

    CERN Document Server

    Klay, J L; Alexander, J M; Anderson, M; Best, D; Brady, F P; Case, T; Caskey, W; Cebra, D; Chance, J L; Chung, P; Cole, B; Crowe, K; Das, A C; Draper, J E; Gilkes, M L; Gushue, S; Heffner, M; Hirsch, A S; Hjort, E L; Huo, L; Justice, M; Kaplan, M; Keane, D; Kintner, J C; Krofcheck, D; Lacey, R A; Law, C; Lauret, J; Lisa, M A; Liu, H; Liu, Y M; McGrath, R; Milosevich, Z; Odyniec, Grazyna Janina; Olson, D L; Panitkin, S Y; Pinkenburg, C H; Porile, N T; Rai, G; Ritter, H G; Romero, J L; Scharenberg, R P; Schröder, L; Srivastava, B; Stone, N T B; Symons, T J M; Wang, S; Wells, R; Whitfield, J; Wienold, T; Witt, R; Wood, L; Zhang Wei Ning

    2002-01-01

    Longitudinal flow extracted from the rapidity density distributions of protons from Au + Au collisions measured by the E895 Collaboration in the energy range from 2 to 8 AGeV at the Brookhaven AGS is presented. The almost 4pi coverage provided by the EOS Time Projection Chamber allows reconstruction of proton transverse mass spectra over a broad range of rapidities. The asymptotic slope of each mt-m0 spectrum provides a temperature with which to calculate an expected dN/dy using a thermal model which includes collective longitudinal flow. This expected dN/dy is fit to the data to extract the longitudinal flow. The results show an approximately linear increase in the longitudinal flow velocity, beta*gamma_{L}, as a function of the logarithm of beam energy.

  3. Fibroma induction in rat skin following single or multiple doses of 1.0 GeV/nucleon 56Fe ions from the Brookhaven Alternating Gradient Synchrotron (AGS)

    Science.gov (United States)

    Burns, F. J.; Zhao, P.; Xu, G.; Roy, N.; Loomis, C.

    2001-01-01

    Rat skin was exposed to the plateau region of the 1.0 GeV/nucleon 56Fe beam at the Brookhaven AGS. Rats were irradiated or not with single of split doses of 56Fe or argon; some 56Fe-exposed rats were fed 250 ppm retinyl acetate continuously in the lab chow beginning 1 week before irradiation. All lesions were noted, photographed and identified for eventual histological diagnosis. The preponderance of the tumors so far are fibromas. The data show that single doses of 56Fe ions are 2 or 3 fold more effective than argon in producing tumors at 4.5 Gy but are about equally effective at 3.0 Gy and 9.0 Gy. The presence of 250 ppm retinyl acetate in the lab chow reduced the incidence of tumors by about 50-60% in comparison to groups exposed only to the radiation. These are preliminary findings based on only about one-fourth the eventual number of tumors expected.

  4. Brookhaven highlights - Brookhaven National Laboratory 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    This report highlights research conducted at Brookhaven National Laboratory in the following areas: alternating gradient synchrotron; physics; biology; national synchrotron light source; department of applied science; medical; chemistry; department of advanced technology; reactor; safety and environmental protection; instrumentation; and computing and communications.

  5. Brookhaven Linac Isotope Producer

    Data.gov (United States)

    Federal Laboratory Consortium — The Brookhaven Linac Isoptope Producer (BLIP)—positioned at the forefront of research into radioisotopes used in cancer treatment and diagnosis—produces commercially...

  6. AGS-2000: Experiments for the 21. Century. Proceedings of the workshop held at Brookhaven National Laboratory, May 13--17, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Littenberg, L. [ed.] [Brookhaven National Lab., Upton, NY (United States); Sandweiss, J. [ed.] [Yale Univ., New Haven, CT (United States)

    1996-10-01

    The AGS has a vital and interesting potential for new research. The reasons for this are a fortunate concomitance of the energy chosen for the AGS and the steady stream of technological advances which have both increased the intensity and flexibility of the AGS beams, and the capability of detectors to use these new beam parameters. The physics potentials of the future AGS program can be roughly divided into three broad areas. (1) fundamental elementary particle studies (based on rare kaon decays, rare muon processes and searches for new particles); (2) non-perturbative QCD; and (3) heavy ion physics. The overriding considerations for the operation of the AGS in the next decade must, of course, be the interest and potential of the scientific program. However, once that has been established, there are other aspects of the AGS program which deserve mention. Although experiments at the AGS are of increasing sophistication, they are smaller, less expensive, and more quickly executed than experiments at newer, larger facilities. Finally, the authors note that since the AGS must be maintained as a viable accelerator to serve as an injector to RHIC, the cost of an AGS fixed target experiment need be only the incremental cost of the experiment itself along with some modest additional operating costs. This means that AGS fixed target experiments are substantially cheaper than they would have been before the RHIC era. The remainder of this document contains brief summaries of the experiments considered by the working groups in the AGS-2000 Workshop. These summaries expand on points discussed here.

  7. H particle searches at Brookhaven

    Energy Technology Data Exchange (ETDEWEB)

    Chrien, R.E. [Brookhaven National Lab., Upton, NY (United States). Physics Dept.

    1997-09-01

    Following the suggestion by R.L. Jaffe twenty years ago, researchers have been trying to establish the existence of a six-quark object, termed the H dibaryon, predicted by the phenomenological quark bag model. This object quickly became the focus of experimental searches at several locations, including the AGS. This search still continues, with perhaps the most active program being carried out at the 2.0 GeV/c beam line at the BNL-AGS. The research was considerably enhanced by the writing of two notable papers at BNL by Aerts and Dover, which gave quantitative predictions for H-production cross sections in two very different reaction mechanisms. One of these, the formation of cascade atomic deuterium to form the H by fusion, had been first suggested by P.D. Barnes. The 2.0 GeV/c line at the AGS was specifically designed to provide an adequate kaon flux for double strangeness and charge exchange reactions. It has been used for two H searches, E813 and E836, as well as for several {Lambda}{Lambda} searches, E885 and E906. These four experiments are setting significant limits on H-production. The results of these experiments are discussed, and descriptions of related H searches at Brookhaven are given.

  8. The new Brookhaven $(g-2)_{\\mu}$ experiment

    CERN Document Server

    Hertzog, D W; Bunce, G M; Carey, R M; Cushman, P B; Danby, G T; Debevec, P T; Deng, H; Deninger, W J; Dhawan, S K; Druzhinin, V P; Duong, L; Earle, W; Efstathiadis, E F; Farley, Francis J M; Fedotovich, G V; Giron, S; Gray, F; Grosse-Perdekamp, M; Grossmann, A; Haeberlen, U; Hare, M; Hazen, E S; Hughes, V W; Iwassaki, M; Jungmann, Klaus; Kawall, D; Kawamura, M; Khazin, B I; Kindem, J; Krienen, F; Kronkvist, I J; Larsen, R; Lee, Y Y; Liu, W; Logashenko, I B; McNabb, R; Meng, W; Mi, J L; Miller, J P; Morse, W M; Onderwater, Gerco; Orlov, Yu F; Pai, C; Polly, C; Pretz, J; Prigl, R; zu Putlitz, Gisbert; Redin, S I; Rind, O; Roberts, B L; Ryskulov, N M; Sanders, R; Sedykh, S N; Semertzidis, Y K; Serednyakov, S I; Shatunov, Yu M; Solodov, E P; Sossong, M; Steinmetz, A; Sulak, Lawrence R; Timmermans, C; Trofimov, A V; Urner, D; Warburton, D; Winn, D; Xu, Q; Yamamoto, A; Zimmerman, D

    1999-01-01

    A new assault on the muon's anomalous magnetic moment has begun with a vigorous effort by the Brookhaven E821 collaboration. The present group has refined the design used in a series of successful CERN experiments in order to lower the systematic uncertainties. Consequently it will be possible to take advantage of the greatly increased muon flux provided for at the AGS. Several novel techniques are employed, of which the most significant is a direct muon injection scheme. Upon reaching the goal of the experiment, comparison with theory will offer sensitive teats of both the electroweak corrections and physics beyond the standard model. At the time of this symposium, data from the first engineering run has been analyzed, yielding a result whose precision and value are comparable to those generated by the last CERN effort. (23 refs).

  9. Brookhaven leak reactor to close

    CERN Multimedia

    MacIlwain, C

    1999-01-01

    The DOE has announced that the High Flux Beam Reactor at Brookhaven is to close for good. Though the news was not unexpected researchers were angry the decision had been taken before the review to assess the impact of reopening the reactor had been concluded (1 page).

  10. AGS experiments - 1994, 1995, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1997-01-01

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

  11. Brookhaven Highlights, January 1982-March 1983

    Energy Technology Data Exchange (ETDEWEB)

    Kuper, J.B.H.; Rustad, M.C. (eds.)

    1983-01-01

    Research at Brookhaven National Laboratory is summarized. Major headings are high energy physics, physics and chemistry, life sciences, applied energy science, support activities and administration. (GHT)

  12. BROOKHAVEN NATIONAL LABORATORY WILDLIFE MANAGEMENT PLAN.

    Energy Technology Data Exchange (ETDEWEB)

    NAIDU,J.R.

    2002-10-22

    The purpose of the Wildlife Management Plan (WMP) is to promote stewardship of the natural resources found at the Brookhaven National Laboratory (BNL), and to integrate their protection with pursuit of the Laboratory's mission.

  13. ATLAS Overview Week at Brookhaven

    CERN Multimedia

    Pilcher, J

    Over 200 ATLAS participants gathered at Brookhaven National Laboratory during the first week of June for our annual overview week. Some system communities arrived early and held meetings on Saturday and Sunday, and the detector interface group (DIG) and Technical Coordination also took advantage of the time to discuss issues of interest for all detector systems. Sunday was also marked by a workshop on the possibilities for heavy ion physics with ATLAS. Beginning on Monday, and for the rest of the week, sessions were held in common in the well equipped Berkner Hall auditorium complex. Laptop computers became the norm for presentations and a wireless network kept laptop owners well connected. Most lunches and dinners were held on the lawn outside Berkner Hall. The weather was very cooperative and it was an extremely pleasant setting. This picture shows most of the participants from a view on the roof of Berkner Hall. Technical Coordination and Integration issues started the reports on Monday and became a...

  14. Applied programs at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    1991-09-01

    This document overviews the areas of current research at Brookhaven National Laboratory. Technology transfer and the user facilities are discussed. Current topics are presented in the areas of applied physics, chemical science, material science, energy efficiency and conservation, environmental health and mathematics, biosystems and process science, oceanography, and nuclear energy. (GHH)

  15. Brookhaven highlights, October 1979-September 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    Highlights are given for the research areas of the Brookhaven National Laboratory. These areas include high energy physics, physics and chemistry, life sciences, applied energy science (energy and environment, and nuclear energy), and support activities (including mathematics, instrumentation, reactors, and safety). (GHT)

  16. The Amtex DAMA Project: The Brookhaven contribution

    Energy Technology Data Exchange (ETDEWEB)

    Peskin, A.M.

    1995-01-01

    The Amtex Partnership organized in 1993 as a Technology Transfer Collaboration among members of the integrated textile industry, the DOE National Laboratories, a number of universities, and several research/education/technology transfer organizations (RETTs). Under the Amtex umbrella organization, a number of technology areas were defined and individual projects were launched addressing various aspects of improving the health and competitiveness of the American textile industry. The first and, to date, the largest of these has been the computer-based Demand Activated Manufacturing Architecture (DAMA) project. Brookhaven National Laboratory became involved in DAMA beginning in March of 1993 and remained an active participant through January of 1995. It was staffed almost exclusively with personnel of the Computing and Communications Division. This document summarizes the activities and accomplishments of the Brookhaven team in working with the larger collaboration. Detailed information about the Amtex Partnership, the DAMA Project, and specific BNL contributions are documented elsewhere.

  17. The Brookhaven electron analogue, 1953--1957

    Energy Technology Data Exchange (ETDEWEB)

    Plotkin, M.

    1991-12-18

    The following topics are discussed on the Brookhaven electron analogue: L.J. Haworth and E.L. VanHorn letters; Original G.K. Green outline for report; General description; Parameter list; Mechanical Assembly; Alignment; Degaussing; Vacuum System; Injection System; The pulsed inflector; RF System; Ferrite Cavity; Pick-up electrodes and preamplifiers; Radio Frequency power amplifier; Lens supply; Controls and Power; and RF acceleration summary.

  18. AGS 20th anniversary celebration

    Energy Technology Data Exchange (ETDEWEB)

    Baggett, N.V. (ed.)

    1980-05-22

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

  19. Brookhaven National Laboratory site environmental report for calendar year 1994

    Energy Technology Data Exchange (ETDEWEB)

    Naidu, J.R.; Royce, B.A. [eds.

    1995-05-01

    This report documents the results of the Environmental Monitoring Program at Brookhaven National Laboratory and presents summary information about environmental compliance for 1994. To evaluate the effect of Brookhaven National Laboratory`s operations on the local environment, measurements of direct radiation, and a variety of radionuclides and chemical compounds in ambient air, soil, sewage effluent, surface water, groundwater, fauna and vegetation were made at the Brookhaven National Laboratory site and at sites adjacent to the Laboratory.

  20. Brookhaven highlights, October 1, 1989--September 30, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, M.S.; Cohen, A.; Greenberg, D.; Seubert, L.; Kuper, J.B.H. (eds.)

    1990-01-01

    This report discusses research being conducted at Brookhaven National Laboratory. Highlights from all the department are illustrated. The main topics are on accelerator development and applications. (LSP)

  1. Brookhaven highlights. [Fiscal year 1992, October 1, 1991--September 30, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, M.S.; Cohen, A.; Greenberg, D.; Seubert, L. [eds.

    1992-12-31

    This publication provides a broad overview of the research programs and efforts being conducted, built, designed, and planned at Brookhaven National Laboratory. This work covers a broad range of scientific disciplines. Major facilities include the Alternating Gradient Synchrotron (AGS), with its newly completed booster, the National Synchrotron Light Source (NSLS), the High Flux Beam Reactor (HFBR), and the RHIC, which is under construction. Departments within the laboratory include the AGS department, accelerator development, physics, chemistry, biology, NSLS, medical, nuclear energy, and interdepartmental research efforts. Research ranges from the pure sciences, in nuclear physics and high energy physics as one example, to environmental work in applied science to study climatic effects, from efforts in biology which are a component of the human genome project to the study, production, and characterization of new materials. The paper provides an overview of the laboratory operations during 1992, including staffing, research, honors, funding, and general laboratory plans for the future.

  2. Brookhaven highlights, October 1978-September 1979. [October 1978 to September 1979

    Energy Technology Data Exchange (ETDEWEB)

    1979-01-01

    These highlights present an overview of the major research and development achievements at Brookhaven National Laboratory from October 1978 to September 1979. Specific areas covered include: accelerator and high energy physics programs; high energy physics research; the AGS and improvements to the AGS; neutral beam development; heavy ion fusion; superconducting power cables; ISABELLE storage rings; the BNL Tandem accelerator; heavy ion experiments at the Tandem; the High Flux Beam Reactor; medium energy physics; nuclear theory; atomic and applied physics; solid state physics; neutron scattering studies; x-ray scattering studies; solid state theory; defects and disorder in solids; surface physics; the National Synchrotron Light Source ; Chemistry Department; Biology Department; Medical Department; energy sciences; environmental sciences; energy technology programs; National Center for Analysis of Energy Systems; advanced reactor systems; nuclear safety; National Nuclear Data Center; nuclear materials safeguards; Applied Mathematics Department; and support activities. (GHT)

  3. Brookhaven National Laboratory site environmental report for calendar year 1996

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, G.L.; Paquette, D.E.; Naidu, J.R.; Lee, R.J.; Briggs, S.L.K.

    1998-01-01

    This report documents the results of the Environmental Monitoring Program at Brookhaven National Laboratory and summarizes information about environmental compliance for 1996. To evaluate the effect of Brookhaven National Laboratory`s operations on the local environment, measurements of direct radiation, and of a variety of radionuclides and chemical compounds in the ambient air, soil, sewage effluent, surface water, groundwater, fauna, and vegetation were made at the Brookhaven National Laboratory site and at adjacent sites. The report also evaluates the Laboratory`s compliance with all applicable guides, standards, and limits for radiological and non-radiological emissions and effluents to the environment.

  4. New Brookhaven chief seeks cross-cutting research

    CERN Multimedia

    Jones, D

    2003-01-01

    Brookhaven National Laboratory will pursue opportunities for promoting commercial development of energy systems and other technologies while focusing on the lab's primary mission of basic science research, according to the incoming BNL director, Praveen Chaudhari (1 page).

  5. Geothermal materials development at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Kukacka, L.E. [Brookhaven National Lab., Upton, NY (United States)

    1997-12-31

    As part of the DOE/OGT response to recommendations and priorities established by industrial review of their overall R&D program, the Geothermal Materials Program at Brookhaven National Laboratory (BNL) is focusing on topics that can reduce O&M costs and increase competitiveness in foreign and domestic markets. Corrosion and scale control, well completion materials, and lost circulation control have high priorities. The first two topics are included in FY 1997 BNL activities, but work on lost circulation materials is constrained by budgetary limitations. The R&D, most of which is performed as cost-shared efforts with U.S. geothermal firms, is rapidly moving into field testing phases. FY 1996 and 1997 accomplishments in the development of lightweight CO{sub 2}-resistant cements for well completions; corrosion resistant, thermally conductive polymer matrix composites for heat exchange applications; and metallic, polymer and ceramic-based corrosion protective coatings are given in this paper. In addition, plans for work that commenced in March 1997 on thermally conductive cementitious grouting materials for use with geothermal heat pumps (GHP), are discussed.

  6. Report on the Brookhaven Solar Neutrino Experiment

    Science.gov (United States)

    Davis, R. Jr.; Evans, J. C. Jr.

    1976-09-22

    This report is intended as a brief statement of the recent developments and results of the Brookhaven Solar Neutrino Experiment communicated through Professor G. Kocharov to the Leningrad conference on active processes on the sun and the solar neutrino problem. The report summarizes the results of experiments performed over a period of 6 years, from April 1970 to January 1976. Neutrino detection depends upon the neutrino capture reaction /sup 37/Cl(..nu..,e/sup -/)/sup 37/Ar producing the isotope /sup 37/Ar (half life of 35 days). The detector contains 3.8 x 10/sup 5/ liters of C/sub 2/Cl/sub 4/ (2.2 x 10/sup 30/ atoms of /sup 37/Cl) and is located at a depth of 4400 meters of water equivalent (m.w.e.) in the Homestake Gold Mine at Lead, South Dakota, U.S.A. The procedures for extracting /sup 37/Ar and the counting techniques used were described in previous reports. The entire recovered argon sample was counted in a small gas proportional counter. Argon-37 decay events were characterized by the energy of the Auger electrons emitted following the electron capture decay and by the rise-time of the pulse. Counting measurements were continued for a period sufficiently long to observe the decay of /sup 37/Ar.

  7. Geothermal materials development at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Kukacka, L.E.

    1997-06-01

    As part of the DOE/OGT response to recommendations and priorities established by industrial review of their overall R and D program, the Geothermal Materials Program at Brookhaven National Laboratory (BNL) is focusing on topics that can reduce O and M costs and increase competitiveness in foreign and domestic markets. Corrosion and scale control, well completion materials, and lost circulation control have high priorities. The first two topics are included in FY 1997 BNL activities, but work on lost circulation materials is constrained by budgetary limitations. The R and D, most of which is performed as cost-shared efforts with US geothermal firms, is rapidly moving into field testing phases. FY 1996 and 1997 accomplishments in the development of lightweight CO{sub 2}-resistant cements for well completions; corrosion resistant, thermally conductive polymer matrix composites for heat exchange applications; and metallic, polymer and ceramic-based corrosion protective coatings are given in this paper. In addition, plans for work that commenced in March 1997 on thermally conductive cementitious grouting materials for use with geothermal heat pumps (GHP), are discussed.

  8. Multiple Partial Siberian Snakes in the AGS

    Science.gov (United States)

    Takano, J.; Ahrens, L. A.; Bai, M.; Brown, K.; Courant, E. D.; Gardner, C. J.; Glenn, J. W.; Hattori, T.; Huang, H.; Lin, F.; Luccio, A. U.; MacKay, W. W.; Okamura, M.; Roser, T.; Tepikian, S.; Tsoupas, N.; Yip, K.; Zelenski, A.; Zeno, K.

    2007-06-01

    Polarized protons are accelerated up to 24.3 GeV in the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL). To accelerate the beam with preserving the polarization, two different types of helical dipole partial Siberian snake have been installed to the AGS. One is a superconducting magnet (Cold Snake, CSNK), and the other is a normal conducting one (Warm Snake, WSNK). With these snake magnets, the polarization at the AGS extraction achieved 65%. However, the AGS has spin mismatches at the injection and extraction. This description shows calculated results to have better spin matching with using two or three snakes.

  9. MULTIPLE SINGLE BUNCH EXTRACTION TO THE AGS SWITCHYARD.

    Energy Technology Data Exchange (ETDEWEB)

    BROWN,K.A.; AHRENS,L.; GASSNER,D.; GLENN,J.W.; ROSER,T.; SMITH,G.; TSOUPAS,N.; VAN ASSELT,W.; ZENO,K.

    2001-06-18

    In this report we will describe the multiple single bunch extraction system as utilized to deliver beams to the Brookhaven's Alternating Gradient Synchrotron (AGS) switchyard area. We will describe modifications of the AGS switchyard, necessary to allow it to accept bunched beam, and results of the first commissioning of this system. The AGS Switchyard has for many years been used to simultaneously deliver (unbunched) resonant extracted beam to a set of fixed target experiments. In order to accommodate new fixed target experiments which require bunched beams, a method of sending the bunched beams to the AGS Switchyard was required. In addition, by using the AGS switchyard instead of the upstream section of the Brookhaven's Relativistic Heavy Ion Collider (RHIC) injection line the accelerators can be reconfigured quickly and efficiently for filling RHIC. We will present results of the commissioning of this system, which was done in January 2001.

  10. Brookhaven Lab and Argonne Lab scientists invent a plasma valve

    CERN Multimedia

    2003-01-01

    Scientists from Brookhaven National Laboratory and Argonne National Laboratory have received U.S. patent number 6,528,948 for a device that shuts off airflow into a vacuum about one million times faster than mechanical valves or shutters that are currently in use (1 page).

  11. Vertical velocity variances and Reynold stresses at Brookhaven

    DEFF Research Database (Denmark)

    Busch, Niels E.; Brown, R.M.; Frizzola, J.A.

    1970-01-01

    Results of wind tunnel tests of the Brookhaven annular bivane are presented. The energy transfer functions describing the instrument response and the numerical filter employed in the data reduction process have been used to obtain corrected values of the normalized variance of the vertical wind v...... velocity component....

  12. Brookhaven National Laboratory site environmental report for calendar year 1995

    Energy Technology Data Exchange (ETDEWEB)

    Naidu, J.R.; Paquette, D.E.; Schroeder, G.L. [eds.] [and others

    1996-12-01

    This report documents the results of the Environmental Monitoring Program at Brookhaven National Laboratory and summarizes information about environmental compliance for 1995. To evaluate the effect of Brookhaven National Laboratory`s operations on the local environment, measurements of direct radiation, and of a variety of radionuclides and chemical compounds in the ambient air, soil, sewage effluent, surface water, groundwater, fauna, and vegetation were made at the Brookhaven National Laboratory site and at adjacent sites. The report also evaluates the Laboratory`s compliance with all applicable guides, standards, and limits for radiological and nonradiological emissions and effluents to the environment. Areas of known contamination are subject to Remedial Investigation/Feasibility Studies under the Inter Agency Agreement established by the Department of Energy, Environmental Protection Agency and the New York Department of Environmental Conservation. Except for identified areas of soil and groundwater contamination, the environmental monitoring data has continued to demonstrate that compliance was achieved with the applicable environmental laws and regulations governing emission and discharge of materials to the environment. Also, the data show that the environmental impacts at Brookhaven National Laboratory are minimal and pose no threat to the public nor to the environment. This report meets the requirements of Department of Energy Orders 5484.1, Environmental Protection, Safety, and Health Protection Information reporting requirements and 5400.1, General Environmental Protection Programs.

  13. BROOKHAVEN NATIONAL LABORATORY INSTITUTIONAL PLAN FY2003-2007.

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-06-10

    This document presents the vision for Brookhaven National Laboratory (BNL) for the next five years, and a roadmap for implementing that vision. Brookhaven is a multidisciplinary science-based laboratory operated for the U.S. Department of Energy (DOE), supported primarily by programs sponsored by the DOE's Office of Science. As the third-largest funding agency for science in the U.S., one of the DOE's goals is ''to advance basic research and the instruments of science that are the foundations for DOE's applied missions, a base for U.S. technology innovation, and a source of remarkable insights into our physical and biological world, and the nature of matter and energy'' (DOE Office of Science Strategic Plan, 2000 http://www.osti.gov/portfolio/science.htm). BNL shapes its vision according to this plan.

  14. BROOKHAVEN NATIONAL LABORATORY SITE ENVIRONMENTAL REPORT FOR CALENDAR YEAR 1994.

    Energy Technology Data Exchange (ETDEWEB)

    NAIDU,J.R.; ROYCE,B.A.

    1995-05-01

    This report documents the results of the Environmental Monitoring Program at Brookhaven National Laboratory and presents summary information about environmental compliance for 1994. To evaluate the effect of Brookhaven National Laboratory's operations on the local environment, measurements of direct radiation, and a variety of radionuclides and chemical compounds in ambient air, soil, sewage effluent, surface water, groundwater, fauna and vegetation were made at the Brookhaven National Laboratory site and at sites adjacent to the Laboratory. Brookhaven National Laboratory's compliance with all applicable guides, standards, and limits for radiological and nonradiological emissions and effluents to the environment were evaluated. Among the permitted facilities, two instances of pH exceedances were observed at recharge basins, possibly related to rain-water run-off to these recharge basins. Also, the discharge from the Sewage Treatment Plant to the Peconic River exceeded. on ten occasions, one each for fecal coliform and 5-day Biochemical Oxygen Demand (avg.) and eight for ammonia nitrogen. The ammonia and Biochemical Oxygen Demand exceedances were attributed to the cold winter and the routine cultivation of the sand filter beds which resulted in the hydraulic overloading of the filter beds and the possible destruction of nitrifying bacteria. The on-set of warm weather and increased aeration of the filter beds via cultivation helped to alleviate this condition. The discharge of fecal coliform may also be linked to this occurrence, in that the increase in fecal coliform coincided with the increased cultivation of the sand filter beds. The environmental monitoring data has identified site-specific contamination of groundwater and soil. These areas are subject to Remedial Investigation/Feasibility Studies under the Inter Agency Agreement. Except for the above, the environmental monitoring data has continued to demonstrate that compliance was achieved with

  15. Brookhaven highlights for fiscal year 1991, October 1, 1990--September 30, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, M.S.; Cohen, A.; Greenberg, D.; Seubert, L.; Kuper, J.B.H.

    1991-01-01

    This report highlights Brookhaven National Laboratory's activities for fiscal year 1991. Topics from the four research divisions: Computing and Communications, Instrumentation, Reactors, and Safety and Environmental Protection are presented. The research programs at Brookhaven are diverse, as is reflected by the nine different scientific departments: Accelerator Development, Alternating Gradient Synchrotron, Applied Science, Biology, Chemistry, Medical, National Synchrotron Light Source, Nuclear Energy, and Physics. Administrative and managerial information about Brookhaven are also disclosed. (GHH)

  16. Brookhaven highlights for fiscal year 1991, October 1, 1990--September 30, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, M.S.; Cohen, A.; Greenberg, D.; Seubert, L.; Kuper, J.B.H.

    1991-12-31

    This report highlights Brookhaven National Laboratory`s activities for fiscal year 1991. Topics from the four research divisions: Computing and Communications, Instrumentation, Reactors, and Safety and Environmental Protection are presented. The research programs at Brookhaven are diverse, as is reflected by the nine different scientific departments: Accelerator Development, Alternating Gradient Synchrotron, Applied Science, Biology, Chemistry, Medical, National Synchrotron Light Source, Nuclear Energy, and Physics. Administrative and managerial information about Brookhaven are also disclosed. (GHH)

  17. Brookhaven National Laboratory site report for calendar year 1988

    Energy Technology Data Exchange (ETDEWEB)

    Miltenberger, R.P.; Royce, B.A.; Naidu, J.R.

    1989-06-01

    Brookhaven National Laboratory (BNL) is managed by Associated Universities Inc. (AUI). AUI was formed in 1946 by a group of nine universities whose purpose was to create and manage a laboratory in the Northeast in order to advance scientific research in areas of interest to universities, industry, and government. On January 31, 1947, the contract for BNL was approved by the Manhattan District of the Army Corps of Engineers and BNL was established on the former Camp Upton army camp. 54 refs., 21 figs., 78 tabs.

  18. Brookhaven National Laboratory site environmental report for calendar year 1991

    Energy Technology Data Exchange (ETDEWEB)

    Naidu, J.R.; Royce, B.A.; Miltenberger, R.P.

    1992-09-01

    This publication presents the results of BNL`s environmental monitoring and compliance effort and provides an assessment of the impact of Brookhaven National Laboratory (BNL) operations on the environment. This document is the responsibility of the Environmental Protection Section of the Safety and Envirorunental Protection Division. Within this Section, the Environmental Monitoring Group (EMG) sample the environment, interpreted the results, performed the impact analysis of the emissions from BNL, and compiled the information presented here. In this effort, other groups of the Section: Compliance; Analytical; Ground Water; and Quality played a key role in addressing the regulatory aspects and the analysis and documentation of the data, respectively.

  19. Brookhaven National Laboratory site environmental report for calendar year 1991

    Energy Technology Data Exchange (ETDEWEB)

    Naidu, J.R.; Royce, B.A.; Miltenberger, R.P.

    1992-09-01

    This publication presents the results of BNL's environmental monitoring and compliance effort and provides an assessment of the impact of Brookhaven National Laboratory (BNL) operations on the environment. This document is the responsibility of the Environmental Protection Section of the Safety and Envirorunental Protection Division. Within this Section, the Environmental Monitoring Group (EMG) sample the environment, interpreted the results, performed the impact analysis of the emissions from BNL, and compiled the information presented here. In this effort, other groups of the Section: Compliance; Analytical; Ground Water; and Quality played a key role in addressing the regulatory aspects and the analysis and documentation of the data, respectively.

  20. 1995 Annual epidemiologic surveillance report for Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The US Department of Energy`s (DOE) conduct of epidemiologic surveillance provides an early warning system for health problems among workers. This program monitors illnesses and health conditions that result in an absence of five or more consecutive workdays, occupational injuries and illnesses, and disabilities and deaths among current workers. This report summarizes epidemiologic surveillance data collected from Brookhaven National Laboratory (BNL) from January 1, 1995 through December 31, 1995. The data were collected by a coordinator at BNL and submitted to the Epidemiologic Surveillance Data Center, located at Oak Ridge Institute for Science and Education, where quality control procedures and data analyses were carried out.

  1. Brookhaven National Laboratory Institutional Plan FY2001--FY2005

    Energy Technology Data Exchange (ETDEWEB)

    Davis, S.

    2000-10-01

    Brookhaven National Laboratory is a multidisciplinary laboratory in the Department of Energy National Laboratory system and plays a lead role in the DOE Science and Technology mission. The Laboratory also contributes to the DOE missions in Energy Resources, Environmental Quality, and National Security. Brookhaven strives for excellence in its science research and in facility operations and manages its activities with particular sensitivity to environmental and community issues. The Laboratory's programs are aligned continuously with the goals and objectives of the DOE through an Integrated Planning Process. This Institutional Plan summarizes the portfolio of research and capabilities that will assure success in the Laboratory's mission in the future. It also sets forth BNL strategies for our programs and for management of the Laboratory. The Department of Energy national laboratory system provides extensive capabilities in both world class research expertise and unique facilities that cannot exist without federal support. Through these national resources, which are available to researchers from industry, universities, other government agencies and other nations, the Department advances the energy, environmental, economic and national security well being of the US, provides for the international advancement of science, and educates future scientists and engineers.

  2. Summary of failure analysis activities at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Cowgill, M.G.; Czajkowski, C.J.; Franz, E.M.

    1996-10-01

    Brookhaven National Laboratory has for many years conducted examinations related to the failures of nuclear materials and components. These examinations included the confirmation of root cause analyses, the determination of the causes of failure, identification of the species that accelerate corrosion, and comparison of the results of nondestructive examinations with those obtained by destructive examination. The results of those examinations, which had previously appeared in various formats (formal and informal reports, journal articles, etc.), have been collected together and summarized in the present report. The report is divided into sections according to the general subject matter (for example, corrosion, fatigue, etc.). Each section presents summaries of the information contained in specific reports and publications, all of which are fully identified as to title, authors, report number or journal reference, date of publication, and FIN number under which the work was performed.

  3. High field magnet program at Brookhaven National Laboratory

    CERN Document Server

    Ghosh, A; Muratore, J; Parker, B; Sampson, W; Wanderer, P J; Willen, E

    2000-01-01

    The magnet program at Brookhaven National Laboratory (BNL) is focussed on superconducting magnets for particle accelerators. The effort includes magnet production at the laboratory and in industry, magnet R&D, and test facilities for magnets and superconductors. Nearly 2000 magnets-dipoles, quadrupoles, sextupoles and correctors for the arc and insertion regions-were produced for the Relativistic Heavy Ion Collider (RHIC), which is being commissioned. Currently, production of helical dipoles for the polarized proton program at RHIC, insertion region dipoles for the Large Hadron Collider (LHC) at CERN, and an insertion magnet system for the Hadron-Elektron-Ring- Analage (HERA) collider at Deutsches Elektronen-Synchrotron (DESY) is underway. The R&D effort is exploring dipoles with fields above 10 T for use in post-LHC colliders. Brittle superconductors-Nb/sub 3/Sn or HTS-are being used for these magnets. The superconductor test facility measures short-sample currents and other characteristics of sample...

  4. Deriving cleanup guidelines for radionuclides at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Meinhold, A.F.; Morris, S.C.; Dionne, B.; Moskowitz, P.D.

    1997-01-01

    Past activities at Brookhaven National Laboratory (BNL) resulted in soil and groundwater contamination. As a result, BNL was designated a Superfund site under the Comprehensive Environmental Response Compensation and Liability Act (CERCLA). BNL`s Office of Environmental Restoration (OER) is overseeing environmental restoration activities at the Laboratory. With the exception of radium, there are no regulations or guidelines to establish cleanup guidelines for radionuclides in soils at BNL. BNL must derive radionuclide soil cleanup guidelines for a number of Operable Units (OUs) and Areas of Concern (AOCs). These guidelines are required by DOE under a proposed regulation for radiation protection of public health and the environment as well as to satisfy the requirements of CERCLA. The objective of this report is to propose a standard approach to deriving risk-based cleanup guidelines for radionuclides in soil at BNL. Implementation of the approach is briefly discussed.

  5. WILDLAND FIRE MANAGEMENT PLAN FOR BROOKHAVEN NATIONAL LABORATORY.

    Energy Technology Data Exchange (ETDEWEB)

    ENVIRONMENTAL AND WASTE MANAGEMENT SERVICES DIVISION

    2003-09-01

    This Wildland Fire Management Plan (FMP) for Brookhaven National Lab (BNL) and the Upton Ecological and Research Reserve (Upton Reserve) is based on the U.S. Fish & Wildlife Service (FWS) fire management planning procedures and was developed in cooperation with the Department of Energy (DOE) by Brookhaven Science Associates. As the Upton Reserve is contained within the BNL 5,265-acre site, it is logical that the plan applies to both the Upton Reserve and BNL. The Department of the Interior policy for managing wildland fires requires that all areas managed by FWS that can sustain fire must have an FMP that details fire management guidelines for operational procedures and specifies values to be protected or enhanced. Fire management plans provide guidance on fire preparedness, fire prevention, wildfire suppression, and the use of controlled, ''prescribed'' fires and mechanical means to control the amount of available combustible material. Values reflected in the BNL/Upton Reserve Wildland FMP include protecting life and public safety; Lab properties, structures and improvements; cultural and historical sites; neighboring private and public properties; and endangered and threatened species and species of concern. Other values supported by the plan include the enhancement of fire-dependent ecosystems at BNL and the Upton Reserve. This FMP will be reviewed periodically to ensure the fire program advances and evolves with the missions of FWS, BNL, and the Upton Reserve. This Fire Management Plan is a modified version of the Long Island National Wildlife Refuge Complex Fire plan (updated in 2000), which contains all FWS fire plan requirements and is presented in the format specified by the national template for fire management plans adopted under the National Fire Plan. The DOE is one of the signatory agencies on the National Fire Plan. FWS shall be, through an Interagency Agreement dated November 2000 (Appendix C), responsible for coordinating and

  6. Scientists at Brookhaven contribute to the development of a better electron accelerator

    CERN Multimedia

    2004-01-01

    Scientists working at Brookhaven have developed a compact linear accelerator called STELLA (Staged Electron Laser Acceleration). Highly efficient, it may help electron accelerators become practical tools for applications in industry and medicine, such as radiation therapy (1 page)

  7. Proto-2, an ALICE detector prototype, part of the STAR experiment at the Brookhaven National Laboratory

    CERN Multimedia

    2002-01-01

    Proto-2, an LAICE detector prototype, overcame its prototype status to become a real part of the SDTAR, epxeriment at the US Brookhaven National Laboratory. After more than two years across the ocean, it has just arrived back at CERN.

  8. Tiger Team assessment of the Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    1990-06-01

    This report documents the results of the Department of Energy's (DOE's) Tiger Team Assessment conducted at Brookhaven National Laboratory (BNL) in Upton, New York, between March 26 and April 27, 1990. The BNL is a multiprogram laboratory operated by the Associated Universities, Inc., (AUI) for DOE. The purpose of the assessment was to provide the status of environment, safety, and health (ES H) programs at the Laboratory. The scope of the assessment included a review of management systems and operating procedures and records; observations of facility operations; and interviews at the facilities. Subteams in four areas performed the review: ES H, Occupational Safety and Health, and Management and Organization. The assessment was comprehensive, covering all areas of ES H activities and waste management operations. Compliance with applicable Federal, State, and local regulations; applicable DOE Orders; and internal BNL requirements was assessed. In addition, the assessment included an evaluation of the adequacy and effectiveness of the DOE and the site contractor, Associated Universities, Inc. (AUI), management, organization, and administration of the ES H programs at BNL.

  9. CULTURAL RESOURCE MANAGEMENT PLAN FOR BROOKHAVEN NATIONAL LABORATORY.

    Energy Technology Data Exchange (ETDEWEB)

    DAVIS, M.

    2005-04-01

    The Cultural Resource Management Plan (CRMP) for Brookhaven National Laboratory (BNL) provides an organized guide that describes or references all facets and interrelationships of cultural resources at BNL. This document specifically follows, where applicable, the format of the U.S. Department of Energy (DOE) Environmental Guidelines for Development of Cultural Resource Management Plans, DOE G 450.1-3 (9-22-04[m1]). Management strategies included within this CRMP are designed to adequately identify the cultural resources that BNL and DOE consider significant and to acknowledge associated management actions. A principal objective of the CRMP is to reduce the need for additional regulatory documents and to serve as the basis for a formal agreement between the DOE and the New York State Historic Preservation Officer (NYSHPO). The BNL CRMP is designed to be a ''living document.'' Each section includes identified gaps in the management plan, with proposed goals and actions for addressing each gap. The plan will be periodically revised to incorporate new documentation.

  10. Decommissioning of the high flux beam reactor at Brookhaven Lab

    Energy Technology Data Exchange (ETDEWEB)

    Hu, J.P. [National Synchrotron Light Source, Brookhaven Laboratory, Upton, NY 11973 (United States); Reciniello, R.N. [Radiological Control Div., Brookhaven Laboratory, Upton, NY 11973 (United States); Holden, N.E. [National Nuclear Data Center, Brookhaven Laboratory, Upton, NY 11973 (United States)

    2011-07-01

    The high-flux beam reactor (HFBR) at the Brookhaven National Laboratory was a heavy water cooled and moderated reactor that achieved criticality on Oct. 31, 1965. It operated at a power level of 40 megawatts. An equipment upgrade in 1982 allowed operations at 60 megawatts. After a 1989 reactor shutdown to reanalyze safety impact of a hypothetical loss of coolant accident, the reactor was restarted in 1991 at 30 megawatts. The HFBR was shut down in December 1996 for routine maintenance and refueling. At that time, a leak of tritiated water was identified by routine sampling of groundwater from wells located adjacent to the reactor's spent fuel pool. The reactor remained shut down for almost three years for safety and environmental reviews. In November 1999 the United States Dept. of Energy decided to permanently shut down the HFBR. The decontamination and decommissioning of the HFBR complex, consisting of multiple structures and systems to operate and maintain the reactor, were complete in 2009 after removing and shipping off all the control rod blades. The emptied and cleaned HFBR dome, which still contains the irradiated reactor vessel, is presently under 24/7 surveillance for safety. Detailed dosimetry performed for the HFBR decommissioning during 1996-2009 is described in the paper. (authors)

  11. Decommissioning of the High Flux Beam Reactor at Brookhaven Lab

    Energy Technology Data Exchange (ETDEWEB)

    Hu, J. P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Reciniello, R. N. [Brookhaven National Lab. (BNL), Upton, NY (United States); Holden, N. E. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2011-05-27

    The High Flux Beam Reactor at the Brookhaven National Laboratory was a heavy water cooled and moderated reactor that achieved criticality on October 31, 1965. It operated at a power level of 40 mega-watts. An equipment upgrade in 1982 allowed operations at 60 mega-watts. After a 1989 reactor shutdown to reanalyze safety impact of a hypothetical loss of coolant accident, the reactor was restarted in 1991 at 30 mega-watts. The HFBR was shutdown in December 1996 for routine maintenance and refueling. At that time, a leak of tritiated water was identified by routine sampling of ground water from wells located adjacent to the reactor’s spent fuel pool. The reactor remained shutdown for almost three years for safety and environmental reviews. In November 1999 the United States Department of Energy decided to permanently shutdown the HFBR. The decontamination and decommissioning of the HFBR complex, consisting of multiple structures and systems to operate and maintain the reactor, were complete in 2009 after removing and shipping off all the control rod blades. The emptied and cleaned HFBR dome which still contains the irradiated reactor vessel is presently under 24/7 surveillance for safety. Details of the HFBR cleanup conducted during 1999-2009 will be described in the paper.

  12. Technical Safety Appraisal of the Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-01

    The purpose of the Technical Safety Appraisal (TSA) was to assess the effectiveness of representative safety and health programs at the Brookhaven National Laboratory (BNL) through the evaluation of activities at selected facilities and in selected safety disciplines. The TSA was conducted in accordance with established procedures. The following BNL safety and health program elements were reviewed as a part of this TSA: Organization and Administration, Operations, Maintenance, Training and Certification, Nuclear Criticality Safety, Auxiliary Systems, Technical Support, Site/Facility Safety Review, Emergency Preparedness, Radiological Protection, Industrial Hygiene, Occupational Safety, Fire Protection, Quality Verification, and Medical Services. The TSA was conducted from March 26--April 12, 1990. The evaluation was conducted by a team of experts assembled by EH, Office of Safety Appraisals (OSA). TSAs are operationally focused. As such, in terms of safety, health, and quality verification, the site and selected facilities were appraised relative to operations, and the condition of equipment and facilities. The evaluation thus addresses whether current operations are being conducted within the operational safety procedures established for specific facilities and activities.

  13. Tiger Team assessment of the Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    1990-06-01

    This report documents the results of the Department of Energy's (DOE's) Tiger Team Assessment conducted at Brookhaven National Laboratory (BNL) in Upton, New York, between March 26 and April 27, 1990. The BNL is a multiprogram laboratory operated by the Associated Universities, Inc., (AUI) for DOE. The purpose of the assessment was to provide the status of environment, safety, and health (ES H) programs at the laboratory. The scope of the assessment included a review of management systems and operating procedures and records; observations of facility operations; and interviews at the facilities. Subteams in four areas performed the review: ES H, Occupational Safety and Health, and Management and Organization. The assessment was comprehensive, covering all areas of ES H activities and waste management operations. Compliance with applicable Federal, State, and local regulations; applicable DOE Orders; and internal BNL requirements was assessed. In addition, the assessment included an evaluation of the adequacy and effectiveness of the DOE and the site contractor, Associated Universities, Inc. (AUI), management, organization, and administration of the ES H programs at BNL. This volume contains appendices.

  14. Environmental Survey preliminary report, Brookhaven National Laboratory, Upton, New York

    Energy Technology Data Exchange (ETDEWEB)

    1988-06-01

    This report presents the preliminary findings from the first phase of the Environmental Survey of the United States Department of Energy (DOE) Brookhaven National Laboratory (BNL) conducted April 6 through 17, 1987. The Survey is being conducted by an interdisciplinary team of environmental specialists, led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual team components are being supplied by a private contractor. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with BNL. The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at BNL, and interviews with site personnel. The Survey team developed a Sampling and Analysis Plan to assist in further assessing specific environmental problems identified during its on-site activities. The Sampling and Analysis Plan will be executed by Oak Ridge National Laboratory. When completed, the results will be incorporated into the BNL Environmental Survey Interim Report. The Interim Report will reflect the final determinations of the BNL Survey. 80 refs., 24 figs., 48 tabs.

  15. Design of the beryllium window for Brookhaven Linac Isotope Producer

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Mapes, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Raparia, D. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-11-01

    In the Brookhaven Linac Isotope Producer (BLIP) beam line, there were two Beryllium (Be) windows with an air gap to separate the high vacuum upstream side from low vacuum downstream side. There had been frequent window failures in the past which affected the machine productivity and increased the radiation dose received by workers due to unplanned maintenance. To improve the window life, design of Be window is reexamined. Detailed structural and thermal simulations are carried out on Be window for different design parameters and loading conditions to come up with better design to improve the window life. The new design removed the air gap and connect the both beam lines with a Be window in-between. The new design has multiple advantages such as 1) reduces the beam energy loss (because of one window with no air gap), 2) reduces air activation due to nuclear radiation and 3) increased the machine reliability as there is no direct pressure load during operation. For quick replacement of this window, an aluminum bellow coupled with load binder was designed. There hasn’t been a single window failure since the new design was implemented in 2012.

  16. HOM identification by bead pulling in the Brookhaven ERL cavity

    CERN Document Server

    Hahn, H; Jain, Puneet; Johnson, Elliott C; Xu, Wencan

    2014-01-01

    Exploratory measurements of the Brookhaven Energy Recovery Linac (ERL) cavity at superconducting temperature produced a long list of high order modes (HOMs). The niobium 5-cell cavity is terminated at each end with HOM ferrite dampers that successfully reduce the Q-factors to levels required to avoid beam break up (BBU) instabilities. However, a number of un-damped resonances with Q≥106 were found at 4 K and their mode identification forms the focus of this paper. The approach taken here consists of bead pulling on a copper (Cu) replica of the ERL cavity with dampers involving various network analyzer measurements. Several different S21 transmission measurements are used, including those taken from the fundamental input coupler to the pick-up probe across the cavity, others between beam-position monitor probes in the beam tubes, and also between probes placed into the cells. The bead pull technique suitable for HOM identification with a metallic needle or dielectric bead is detailed. This paper presents the...

  17. Brookhaven National Laboratory 2008 Site Environment Report Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Brookhaven National Laboratory

    2009-10-01

    Brookhaven National Laboratory (BNL) prepares an annual Site Environmental Report (SER) in accordance with DOE Order 231.1A, Environment, Safety and Health Reporting of the U.S. Department of Energy. The report is written to inform the public, regulators, employees, and other stakeholders of the Laboratory's environmental performance during the calendar year in review. Volume I of the SER summarizes environmental data; environmental management performance; compliance with applicable DOE, federal, state, and local regulations; and performance in restoration and surveillance monitoring programs. BNL has prepared annual SERs since 1971 and has documented nearly all of its environmental history since the Laboratory's inception in 1947. Volume II of the SER, the Groundwater Status Report, also is prepared annually to report on the status of and evaluate the performance of groundwater treatment systems at the Laboratory. Volume II includes detailed technical summaries of groundwater data and its interpretation, and is intended for internal BNL users, regulators, and other technically oriented stakeholders. A brief summary of the information contained in Volume II is included in this volume in Chapter 7, Groundwater Protection. Both reports are available in print and as downloadable files on the BNL web page at http://www.bnl.gov/ewms/ser/. An electronic version on compact disc is distributed with each printed report. In addition, a summary of Volume I is prepared each year to provide a general overview of the report, and is distributed with a compact disc containing the full report.

  18. The Founding of the Brookhaven National Laboratory - Associated Universities, Inc.

    Energy Technology Data Exchange (ETDEWEB)

    BROOKHAVEN NATIONAL LABORATORY

    1948-01-15

    At the end of the war it became apparent that the teamwork of government and scientific institutions, which had been so effective in wartime work, must somehow be perpetuated in order to insure the continued progress of nuclear science in peace time. The enormous expense of the tools needed to pursue the next steps in this research -- nuclear reactors and high energy accelerators -- and the shortage of scientifically trained personnel pointed towards the establishment of a cooperative laboratory. Such a laboratory, using government funds, could carry out a comprehensive research program that would benefit the many interested research groups throughout the country. As a result of the wartime programs under the Manhattan District, centers of research in nuclear science were already active at the Radiation Laboratory in Berkeley, California, at Los Alamos in New Mexico, at the Clinton Laboratories in Oak Ridge, Tennessee and at the Argonne Laboratory in Chicago. No analogous nuclear research laboratories, however, had developed in the Northeast, and since so much of the nation's scientific talent and industrial activities are concentrated in the northeastern states, it was proposed that a new laboratory be established near New York City. As a result of this plan, the Brookhaven National Laboratory is now in operation at Upton, Long Island. The work of this Laboratory is performed under a contract between the Atomic Energy Commission (AEC) and a corporation, Associated Universities, Inc. (AUI) , formed by representatives of nine of the larger private universities in the northeast: Columbia, Cornell, Harvard, Johns Hopkins, the Massachusetts Institute of Technology, the University of Pennsylvania, Princeton, the University of Rochester, and Yale. The purpose of this laboratory is the advancement of knowledge in the fundamentals of nuclear science, the extension of its application to other fields, and the training of young scientists in these new subjects. This

  19. Brookhaven National Laboratory site environmental report for calendar year 1993

    Energy Technology Data Exchange (ETDEWEB)

    Naidu, J.R.; Royce, B.A. [eds.

    1994-05-01

    This report documents the results of the Environmental Monitoring Program at BNL and presents summary information about environmental compliance for 1993. To evaluate the effect of BNL operations on the local environment, measurements of direct radiation, and a variety of radionuclides and chemical compounds in ambient air, soil, sewage effluent, surface water, ground water and vegetation were made at the BNL site and at sites adjacent to the Laboratory. Brookhaven National Laboratory`s compliance with all applicable guides, standards, and limits for radiological and nonradiological emissions to the environment were evaluated. Among the permitted facilities, two instances, of pH exceedances were observed at recharge basins, possible related to rain-water run-off to these recharge basins. Also, the discharge from the Sewage Treatment Plant (STP) to the Peconic River exceeded on five occasions, three for residual chlorine and one each for iron and ammonia nitrogen. The chlorine exceedances were related to a malfunctioning hypochlorite dosing pump and ceased when the pump was repaired. While the iron and ammonia-nitrogen could be the result of disturbances to the sand filter beds during maintenance. The environmental monitoring data has identified site-specific contamination of ground water and soil. These areas are subject to Remedial Investigation/Feasibility Studies (RI/FS) under the Inter Agency Agreement (IAG). Except for the above, the environmental monitoring data has continued to demonstrate that compliance was achieved with applicable environmental laws and regulations governing emission and discharge of materials to the environment, and that the environmental impacts at BNL are minimal and pose no threat to the public or to the environment. This report meets the requirements of DOE Orders 5484. 1, Environmental Protection, Safety, and Health Protection Information reporting requirements and 5400.1, General Environmental Protection Programs.

  20. NATURAL RESOURCE MANAGEMENT PLAN FOR BROOKHAVEN NATIONAL LABORATORY.

    Energy Technology Data Exchange (ETDEWEB)

    GREEN,T.ET AL.

    2003-12-31

    Brookhaven National Laboratory (BNL) is located near the geographic center of Long Island, New York. The Laboratory is situated on 5,265 acres of land composed of Pine Barrens habitat with a central area developed for Laboratory work. In the mid-1990s BNL began developing a wildlife management program. This program was guided by the Wildlife Management Plan (WMP), which was reviewed and approved by various state and federal agencies in September 1999. The WMP primarily addressed concerns with the protection of New York State threatened, endangered, or species of concern, as well as deer populations, invasive species management, and the revegetation of the area surrounding the Relativistic Heavy Ion Collider (RHIC). The WMP provided a strong and sound basis for wildlife management and established a basis for forward motion and the development of this document, the Natural Resource Management Plan (NRMP), which will guide the natural resource management program for BNL. The body of this plan establishes the management goals and actions necessary for managing the natural resources at BNL. The appendices provide specific management requirements for threatened and endangered amphibians and fish (Appendices A and B respectively), lists of actions in tabular format (Appendix C), and regulatory drivers for the Natural Resource Program (Appendix D). The purpose of the Natural Resource Management Plan is to provide management guidance, promote stewardship of the natural resources found at BNL, and to integrate their protection with pursuit of the Laboratory's mission. The philosophy or guiding principles of the NRMP are stewardship, adaptive ecosystem management, compliance, integration with other plans and requirements, and incorporation of community involvement, where applicable.

  1. Natural Resource Management Plan for Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    green, T.

    2011-08-15

    This comprehensive Natural Resource Management Plan (NRMP) for Brookhaven National Laboratory (BNL) was built on the successful foundation of the Wildlife Management Plan for BNL, which it replaces. This update to the 2003 plan continues to build on successes and efforts to better understand the ecosystems and natural resources found on the BNL site. The plan establishes the basis for managing the varied natural resources located on the 5,265 acre BNL site, setting goals and actions to achieve those goals. The planning of this document is based on the knowledge and expertise gained over the past 10 years by the Natural Resources management staff at BNL in concert with local natural resource agencies including the New York State Department of Environmental Conservation, Long Island Pine Barrens Joint Planning and Policy Commission, The Nature Conservancy, and others. The development of this plan is an attempt at sound ecological management that not only benefits BNL's ecosystems but also benefits the greater Pine Barrens habitats in which BNL is situated. This plan applies equally to the Upton Ecological and Research Reserve (Upton Reserve). Any difference in management between the larger BNL area and the Upton Reserve are noted in the text. The purpose of the Natural Resource Management Plan (NRMP) is to provide management guidance, promote stewardship of the natural resources found at BNL, and to sustainably integrate their protection with pursuit of the Laboratory's mission. The philosophy or guiding principles of the NRMP are stewardship, sustainability, adaptive ecosystem management, compliance, integration with other plans and requirements, and the incorporation of community involvement, where applicable. The NRMP is periodically reviewed and updated, typically every five years. This review and update was delayed to develop documents associated with a new third party facility, the Long Island Solar Farm. This two hundred acre facility will result in

  2. Wildland Fire Management Plan for Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Green,T.

    2009-10-23

    This Wildland Fire Management Plan (FMP) for Brookhaven National Lab (BNL) updates the 2003 plan incorporating changes necessary to comply with DOE Order 450.1 and DOE P 450.4, Federal Wildland Fire Management Policy and Program Review; Wildland and Prescribed Fire Management Policy and implementation Procedures Reference Guide. This current plan incorporates changes since the original draft of the FMP that result from new policies on the national level. This update also removes references and dependence on the U.S. Fish & Wildlife Service and Department of the Interior, fully transitioning Wildland Fire Management responsibilities to BNL. The Department of Energy policy for managing wildland fires requires that all areas, managed by the DOE and/or its various contractors, that can sustain fire must have a FMP that details fire management guidelines for operational procedures associated with wild fire, operational, and prescribed fires. Fire management plans provide guidance on fire preparedness, fire prevention, wildfire suppression, and the use of controlled, 'prescribed' fires and mechanical means to control the amount of available combustible material. Values reflected in the BNL Wildland FMP include protecting life and public safety; Lab properties, structures and improvements; cultural and historical sites; neighboring private and public properties; and endangered, threatened, and species of concern. Other values supported by the plan include the enhancement of fire-dependent ecosystems at BNL. This FMP will be reviewed periodically to ensure the fire program advances and evolves with the missions of the DOE and BNL. This Fire Management Plan is presented in a format that coverers all aspects specified by DOE guidance documents which are based on the national template for fire management plans adopted under the National Fire Plan. The DOE is one of the signatory agencies on the National Fire Plan. This FMP is to be used and implemented for the

  3. A woman like you: Women scientists and engineers at Brookhaven National Laboratory. Careers in action

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    This publication by the women in Science and Engineering introduces career possibilities in science and engineering. It introduces what work and home life are like for women who have already entered these fields. Women at Brookhaven National Laboratory work in a variety of challenging research roles -- from biologist and environmental scientist to safety engineer, from patent lawyer to technician. Brookhaven National Laboratory is a multi-program laboratory which carries out basic and applied research in the physical, biomedical and environmental sciences and in selected energy technologies. The Laboratory is managed by Associated University, Inc., under contract with the US Department of Energy. Brookhaven and the other national laboratories, because of their enormous research resources, can play a critical role in a education and training of the workforce.

  4. A woman like you: Women scientists and engineers at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Benkovitz, Carmen; Bernholc, Nicole; Cohen, Anita; Eng, Susan; Enriquez-Leder, Rosario; Franz, Barbara; Gorden, Patricia; Hanson, Louise; Lamble, Geraldine; Martin, Harriet; Mastrangelo, Iris; McLane, Victoria; Villela, Maria-Alicia; Vivirito, Katherine; Woodhead, Avril

    1991-01-01

    This publication by the women in Science and Engineering introduces career possibilities in science and engineering. It introduces what work and home life are like for women who have already entered these fields. Women at Brookhaven National Laboratory work in a variety of challenging research roles -- from biologist and environmental scientist to safety engineer, from patent lawyer to technician. Brookhaven National Laboratory is a multi-program laboratory which carries out basic and applied research in the physical, biomedical and environmental sciences and in selected energy technologies. The Laboratory is managed by Associated University, Inc., under contract with the US Department of Energy. Brookhaven and the other national laboratories, because of their enormous research resources, can play a critical role in a education and training of the workforce.

  5. Aberration-Coreected Electron Microscopy at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Zhu,Y.; Wall, J.

    2008-04-01

    The last decade witnessed the rapid development and implementation of aberration correction in electron optics, realizing a more-than-70-year-old dream of aberration-free electron microscopy with a spatial resolution below one angstrom [1-9]. With sophisticated aberration correctors, modern electron microscopes now can reveal local structural information unavailable with neutrons and x-rays, such as the local arrangement of atoms, order/disorder, electronic inhomogeneity, bonding states, spin configuration, quantum confinement, and symmetry breaking [10-17]. Aberration correction through multipole-based correctors, as well as the associated improved stability in accelerating voltage, lens supplies, and goniometers in electron microscopes now enables medium-voltage (200-300kV) microscopes to achieve image resolution at or below 0.1nm. Aberration correction not only improves the instrument's spatial resolution but, equally importantly, allows larger objective lens pole-piece gaps to be employed thus realizing the potential of the instrument as a nanoscale property-measurement tool. That is, while retaining high spatial resolution, we can use various sample stages to observe the materials response under various temperature, electric- and magnetic- fields, and atmospheric environments. Such capabilities afford tremendous opportunities to tackle challenging science and technology issues in physics, chemistry, materials science, and biology. The research goal of the electron microscopy group at the Dept. of Condensed Matter Physics and Materials Science and the Center for Functional Nanomaterials, as well as the Institute for Advanced Electron Microscopy, Brookhaven National Laboratory (BNL), is to elucidate the microscopic origin of the physical- and chemical-behavior of materials, and the role of individual, or groups of atoms, especially in their native functional environments. We plan to accomplish this by developing and implementing various quantitative

  6. Brookhaven highlights, fiscal year 1985, October 1, 1984-September 30, 1985

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    Activities at Brookhaven National Laboratory are briefly discussed. These include work at the National Synchrotron Light Source, the High Flux Beam Reactor, and the Alternating Gradient Synchrotron. Areas of research include heavy ion reactions, neutrino oscillations, low-level waste, nuclear data, medicine, biology, chemistry, parallel computing, optics. Also provided are general and administrative news, a financial report. (LEW)

  7. T.D. LEE: RELATIVISTIC HEAVY ION COLLISIONS AND THE RIKEN BROOKHAVEN CENTER.

    Energy Technology Data Exchange (ETDEWEB)

    MCLERRAN,L.; SAMIOS, N.

    2006-11-24

    This paper presents the history of Professor T. D. Lee's seminal work on the theory of relativistic heavy ion collisions, and the founding and development of the Riken Brookhaven Center. A number of anecdotes are given about Prof. Lee, and his strong positive effect on his colleagues, particularly young physicists.

  8. Brookhaven Lab physicist William Willis wins the 2003 W.K.H. Panofsky prize

    CERN Document Server

    2003-01-01

    William Willis, a senior physicist Brookhaven National Laboratory, has won the American Physical Society's 2003 W.K.H. Panofsky Prize in Experimental Particle Physics. He received the prize, which consists of $5,000 and a certificate citing his contributions to physics, at the APS meeting in Philadelphia on April 6 (1 page).

  9. Laying the groundwork at the AGS Recent results from experiment E895

    CERN Document Server

    Lisa, M A; Alexander, J M; Anderson, M; Best, D; Brady, F P; Case, T; Caskey, W; Cebra, D; Chance, J L; Chung, P; Cole, B; Crowe, K M; Das, A C; Draper, J E; Gilkes, M L; Gushue, S; Heffner, M; Hirsch, A S; Hjort, E L; Huo, L; Justice, M; Kaplan, M; Keane, D; Kintner, J C; Klay, J L; Krofcheck, D; Lacey, R A; Law, C; Lauret, J; Liu, H; Liu, Y M; McGrath, R; Milosevich, Z; Odyniec, Grazyna Janina; Olson, D L; Panitkin, S Y; Pinkenburg, C H; Porile, N T; Rai, G; Ritter, H G; Romero, J L; Scharenberg, R P; Schröder, L; Srivastava, B; Stone, N T B; Symons, T J M; Wang, S; Wells, R; Whitfield, J; Wienold, T; Witt, R; Wood, L; Zhang Wei Ning

    2002-01-01

    The E895 Collaboration at the Brookhaven AGS has performed a systematic investigation of Au+Au collisions at 2-8 AGeV, using a large-acceptance Time Projection Chamber. In addition to extensive measurements of particle flow, spectra, two-particle interferometry, and strangeness production, we have performed novel hybrid analyses, including azimuthally-sensitive pion HBT, extraction of the six-dimensional pion phasespace density, and a first measurement of the Lambda-proton correlation function.

  10. Radiological environmental monitoring report for Brookhaven National Laboratory 1967--1970

    Energy Technology Data Exchange (ETDEWEB)

    Meinhold, C.B.; Hull, A.P.

    1998-10-01

    Brookhaven National Laboratory (BNL) was established in 1947 on the former Army Camp Upton site located in central Long Island, New York. From the very beginning, BNL has monitored the environment on and around the Laboratory site to assess the effects of its operations on the environment. This document summarizes the environmental data collected for the years 1967, 1968, 1969, and 1970. Thus, it fills a gap in the series of BNL annual environmental reports beginning in 1962. The data in this document reflect measurements for those four years of concentrations and/or amounts of airborne radioactivity, radioactivity in streams and ground water, and external radiation levels in the vicinity of BNL. Also included are estimates, made at that time, of BNL`s contribution to radioactivity in the environment. Among the major scientific facilities operated at BNL are the High Flux Beam Reactor, Medical Research Reactor, Brookhaven Graphite Research Reactor, Alternating Gradient Synchrotron, and the 60-inch Cyclotron.

  11. First magnet constructed for the LHC by Brookhaven National Laboratory, USA

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    CERN has taken delivery of the first US-built contribution to the LHC. The 25-tonne interaction-region dipole magnet, which will guide the LHC´s two counter-rotating beams of protons into collision, was built at the US Brookhaven National Laboratory. It is the first of 20 that the laboratory will ultimately provide and took nine months for more than 100 scientists, engineers and technicians to construct. Brookhaven´s Superconducting Magnet Division is now building the remaining 19 magnets, which will be shipped to CERN later this year. They are provided for the LHC under the terms of a 1998 agreement between CERN and the US Department of Energy and National Science Foundation.

  12. 2003 Brookhaven National Laboratory Annual Illness and Injury Surveillance Report, Revised September 2007

    Energy Technology Data Exchange (ETDEWEB)

    U.S. Department of Energy, Office of Health, Safety and Security, Office of Illness and Injury Prevention Programs

    2007-10-02

    Annual Illness and Injury Surveillance Program report for 2003 for Brookhaven National Lab. The U.S. Department of Energy’s (DOE) commitment to assuring the health and safety of its workers includes the conduct of epidemiologic surveillance activities that provide an early warning system for health problems among workers. The IISP monitors illnesses and health conditions that result in an absence of workdays, occupational injuries and illnesses, and disabilities and deaths among current workers.

  13. Qualitative risk evaluation of environmental restoration programs at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Morris, S.C.

    1996-05-01

    This report documents the evaluation of risks associated with environmental restoration activities at Brookhaven National Laboratory using two tools supplied by DOE to provide a consistent set of risk estimates across the DOE complex: Risk Data Sheets (RDS) and Relative Risk Ranking. The tools are described, the process taken characterized, results provided and discussed. The two approaches are compared and recommendations provided for continuing improvement of the process.

  14. Brookhaven highlights. Report on research, October 1, 1992--September 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, M.S.; Belford, M.; Cohen, A.; Greenberg, D.; Seubert, L. [eds.

    1993-12-31

    This report highlights the research activities of Brookhaven National Laboratory during the period dating from October 1, 1992 through September 30, 1993. There are contributions to the report from different programs and departments within the laboratory. These include technology transfer, RHIC, Alternating Gradient Synchrotron, physics, biology, national synchrotron light source, applied science, medical science, advanced technology, chemistry, reactor physics, safety and environmental protection, instrumentation, and computing and communications.

  15. Experimental status of the AGS Relativistic Heavy Ion Program

    Science.gov (United States)

    Sangster, T. Craig

    1994-10-01

    The universal motivation for colliding large nuclei at relativistic energies is the expectation that a small volume of the primordial quark soup, generally referred to as the Quark-Gluon Plasma (QGP), can be created and studied. The QGP is formed via a phase transition caused by either the extreme baryon densities and/or the extreme temperatures achieved in the overlap zone of the two colliding nuclei. Experiments at the Brookhaven National Laboratory Alternating Gradient Synchrotron (AGS) using a beam of Si nuclei at 14.6 GeV per nucleon on various nuclear targets have been completed. These same experiments are now actively searching for signatures of QGP formation using a beam of Au nuclei at 11.7 GeV per nucleon. This paper briefly summarizes some of the key results from the Si beam program and the current status of the experimental Au beam program at the AGS.

  16. Design study of a normal conducting helical snake for AGS

    CERN Document Server

    Takano, Junpei; Okamura, Masahiro; Roser, Thomas; MacKay, William W; Luccio, Alfredo U; Takano, Koji

    2004-01-01

    A new normal conducting snake magnet is being fabricated for the Alternate Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL). In the Relativistic Heavy Ion Collider (RHIC) project, a superconducting type helical dipole magnets had been developed and it performed successfully in high-energy polarized proton acceleration. The new AGS helical snake has the same basic magnetic structure but is more complicated. To achieve no beam shift and no beam deflection in one magnetic device, helical pitches and rotating angles were carefully calculated. Compared to a superconducting magnet, a normal warm magnet must have a large cross- sectional area of conductors which make it difficult to design a magnet with large helical pitch. We developed a modified window frame structure to accommodate the large number of conductors. Its three dimensional magnetic field was simulated by using OPERA3D/TOSCA. 3 Refs.

  17. 1. 5 GeV/c multiturn shaving extraction and its transport line for the Brookhaven AGS

    Energy Technology Data Exchange (ETDEWEB)

    Weng, W.T.; Blumberg, L.N.; Gill, E.; Soukas, A.; Witkover, R.L.; Egleman, E.; LoSecco, J.; Sulak, L.

    1979-01-01

    A system for fast shaving extraction at 1.5 GeV/c is implemented to extract the circulating beam in five turns. A numerical simulation is first carried out to determine the emittance and the rf structure of the extracted beam. This is followed by several machine study sessions which establish the optimal extraction configuration, confirm the emittance, and modify the transport line for low energy beam. Finally, a one-week run for the Neutrino Oscillation experiment demonstrates that the system is very stable and capable of delivering 7.5 x 10/sup 12/ p/sec with 70% extraction efficiency and 95% transport efficiency.

  18. Laser ion source with solenoid for Brookhaven National Laboratory-electron beam ion source.

    Science.gov (United States)

    Kondo, K; Yamamoto, T; Sekine, M; Okamura, M

    2012-02-01

    The electron beam ion source (EBIS) preinjector at Brookhaven National Laboratory (BNL) is a new heavy ion-preinjector for relativistic heavy ion collider (RHIC) and NASA Space Radiation Laboratory (NSRL). Laser ion source (LIS) is a primary ion source provider for the BNL-EBIS. LIS with solenoid at the plasma drift section can realize the low peak current (∼100 μA) with high charge (∼10 nC) which is the BNL-EBIS requirement. The gap between two solenoids does not cause serious plasma current decay, which helps us to make up the BNL-EBIS beamline.

  19. Laser ion source with solenoid for Brookhaven National Laboratory-electron beam ion sourcea)

    Science.gov (United States)

    Kondo, K.; Yamamoto, T.; Sekine, M.; Okamura, M.

    2012-02-01

    The electron beam ion source (EBIS) preinjector at Brookhaven National Laboratory (BNL) is a new heavy ion-preinjector for relativistic heavy ion collider (RHIC) and NASA Space Radiation Laboratory (NSRL). Laser ion source (LIS) is a primary ion source provider for the BNL-EBIS. LIS with solenoid at the plasma drift section can realize the low peak current (˜100 μA) with high charge (˜10 nC) which is the BNL-EBIS requirement. The gap between two solenoids does not cause serious plasma current decay, which helps us to make up the BNL-EBIS beamline.

  20. Assessment of Energy Efficiency Project Financing Alternatives for Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, W. D.; Hail, John C.; Sullivan, Gregory P.

    2000-02-14

    This document provides findings and recommendations that resulted from an assessment of the Brookhaven National Laboratory by a team from Pacific Northwest National Laboratory to assess the site's potential for various alternative financing options as a means to implement energy-efficiency improvements. The assessment looked for life-cycle cost-effective energy-efficiency improvement opportunities, and through a series of staff interviews, evaluated the various methods by which these opportunities may be financed, while considering availability of funds, staff, and available financing options. This report summarizes the findings of the visit and the resulting recommendations.

  1. Summary of proposed approach for deriving cleanup guidelines for radionuclides in soil at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Meinhold, A.F.; Morris, S.C.; Dionne, B.; Moskowitz, P.D.

    1996-11-01

    Past activities at Brookhaven National Laboratory (BNL) resulted in soil and groundwater contamination. As a result, BNL was designated a Superfund site under the Comprehensive Environmental Response Compensation and Liability Act (CERCLA). BNL`s Office of Environmental Restoration (OER) is overseeing environmental restoration activities at the Laboratory, carried out under an Interagency Agreement (IAG) with the United States Department of Energy (DOE), the United States Environmental Protection Agency (EPA) and the New York State Department of Environmental Conservation (NYSDEC). The objective of this paper is to propose a standard approach to deriving risk-based cleanup guidelines for radionuclides in soil at BNL.

  2. Applications of nuclear techniques for in vivo body composition studies at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Cohn, S.H.; Ellis, K.J.; Vartsky, D.; Vaswani, A.N.; Wielopolski, L.

    1981-01-01

    A series of technical developments and their clinical applications in various nuclear technologies at Brookhaven National Laboratory is described. These include the development of a portable neutron activation facility for measuring cadmium in vivo in kidney and liver, a technique for the measurement of body iron utilizing nuclear resonant scattering of gamma rays, a non-invasive measure of the skeletal levels of lead by an x-ray fluorescence technique, and the development of a pulsed Van de Graaff generator as a source of pulsed neutrons for the measurement of lung silicon. (ACR)

  3. Risk-based priority scoring for Brookhaven National Laboratory environmental restoration programs

    Energy Technology Data Exchange (ETDEWEB)

    Morris, S.C.; Meinhold, A.F.

    1995-05-01

    This report describes the process of estimating the risk associated with environmental restoration programs under the Brookhaven National Laboratory Office of Environmental Restoration. The process was part of an effort across all Department of Energy facilities to provide a consistent framework to communicate risk information about the facilities to senior managers in the DOE Office of Environmental Management to foster understanding of risk activities across programs. the risk evaluation was a qualitative exercise. Categories considered included: Public health and safety; site personnel safety and health; compliance; mission impact; cost-effective risk management; environmental protection; inherent worker risk; environmental effects of clean-up; and social, cultural, political, and economic impacts.

  4. Proceedings of Brookhaven National Laboratory's fusion/synfuel workshop

    Energy Technology Data Exchange (ETDEWEB)

    Fillo, J.A.; Powell, J.R. (eds.)

    1979-01-01

    The fusion synfuels workshop held at Brookhaven National Laboratory (BNL) on August 27-29, 1979 examined the current status of candidate synfuel processes and the R and D required to develop the capability for fusion synfuel production. Participants divided into five working groups, covering the following areas: (1) economics and applications; (2) high-temperature electrolysis; (3) thermochemical processes (including hybrid thermo-electrochemical); (4) blanket and materials; and (5) high-efficiency power cycles. Each working group presented a summary of their conclusions and recommendations to all participants during the third day of the Workshop. These summaries are given.

  5. Is Overeating Behavior Similar to Drug Addiction? (427th Brookhaven Lecture)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Gene-Jack

    2007-09-27

    The increasing number of obese individuals in the U.S. and other countries world-wide adds urgency to the need to understand the mechanisms underlying pathological overeating. Research by the speaker and others at Brookhaven National Laboratory and elsewhere is compiling evidence that the brain circuits disrupted in obesity are similar to those involved in drug addiction. Using positron emission tomography (PET), the speaker and his colleagues have implicated brain dopamine in the normal and the pathological intake of food by humans. During the 427th Brookhaven Lecture, speaker will review the findings and implications of PET studies of obese subjects and then compare them to PET research involving drug-addicted individuals. For example, in pathologically obese subjects, it was found that reductions in striatal dopamine D2 receptors are similar to those observed in drug-addicted subjects. The speaker and his colleagues have postulated that decreased levels of dopamine receptors predisposed subjects to search for strongly rewarding reinforcers, be it drugs for the drug-addicted or food for the obese, as a means to compensate for decreased sensitivity of their dopamine-regulated reward circuits. As the speaker will summarize, multiple but similar brain circuits involved in reward, motivation, learning and inhibitory control are disrupted both in drug addiction and obesity, resulting in the need for a multimodal approach to the treatment of obesity.

  6. Doing More with Less: Cost-effective, Compact Particle Accelerators (489th Brookhaven Lecture)

    Energy Technology Data Exchange (ETDEWEB)

    Trbojevic, Dejan [BNL Collider-Accelerator Department

    2013-10-22

    Replace a 135-ton magnet used for cancer-fighting particle therapies with a magnet that weighs only two tons? Such a swap is becoming possible thanks to new particle accelerator advances being developed by researchers at Brookhaven Lab. With an approach that combines techniques used by synchrotron accelerators with the ability to accept more energy, these new technologies could be used for more than fighting cancer. They could also decrease the lifecycle of byproducts from nuclear power plants and reduce costs for eRHIC—a proposed electron-ion collider for Brookhaven Lab that researchers from around the world would use to explore the glue that holds together the universe’s most basic building blocks and explore the proton-spin puzzle. During this lecture, Dr. Trbojevic provides an overview of accelerator technologies and techniques—particularly a non-scaling, fixed-focused alternating gradient—to focus particle beams using fewer, smaller magnets. He discusses how these technologies will benefit eRHIC and other applications, including particle therapies being developed to combat cancer.

  7. Manipulating Light to Understand and Improve Solar Cells (494th Brookhaven Lecture)

    Energy Technology Data Exchange (ETDEWEB)

    Eisaman, Matthew [BNL, Sustainable Energy Technologies Department

    2014-04-16

    Energy consumption around the world is projected to approximately triple by the end of the century, according to the 2005 Report from the U.S. Department of Energy's Basic Energy Sciences Workshop on Solar Energy Utilization. Much will change in those next 86 years, but for all the power the world needs—for everything from manufacturing and transportation to air conditioning and charging cell phone batteries—improved solar cells will be crucial to meet this future energy demand with renewable energy sources. At Brookhaven Lab, scientists are probing solar cells and exploring variations within the cells—variations that are so small they are measured in billionths of a meter—in order to make increasingly efficient solar cells and ultimately help reduce the overall costs of deploying solar power plants. Dr. Eisaman will discuss DOE's Sunshot Initiative, which aims to reduce the cost of solar cell-generated electricity by 2020. He will also discuss how he and collaborators at Brookhaven Lab are probing different material compositions within solar cells, measuring how efficiently they collect electrical charge, helping to develop a new class of solar cells, and improving solar-cell manufacturing processes.

  8. Optimization of AGS Polarized Proton Operation with the Warm Helical Snake

    CERN Document Server

    Takano, Junpei; Bai, Mei; Brown, Kevin A; Gardner, Chris J; Glenn, Joseph; Hattori, Toshiyuki; Huang, Haixin; Luccio, Alfredo U; MacKay, William W; Okamura, Masahiro; Roser, Thomas; Tepikian, Steven; Tsoupas, Nicholaos

    2005-01-01

    A normal conducting helical dipole partial Siberian snake (Warm Snake) has been installed in the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL) for overcoming all of imperfection depolarizing resonances and reducing the transverse coupling resonances caused by the solenoidal Siberian snake which had been operated in AGS before the last polarized run. The polarized proton beam has been accelerated successfully with the warm snake and the polarization at extraction of the AGS was increased to 50% as opposed to 40% with the solenoidal snake. The magnetic field and beam trajectory in the warm snake was calculated by using the OPERA-3D/TOSCA software. We present optimization of the warm snake with beam during RUN5.

  9. Brookhaven Lab physicists Edward Beebe and Alexander Pikin win 'Brightness Award' for achievement in ion source physics and technology

    CERN Multimedia

    2003-01-01

    "Edward Beebe and Alexander Pikin, physicists at the U.S. Department of Energy's Brookhaven National Laboratory, have been awarded the Ion Source Prize, known as the "Brightness Award," which recognizes and encourages innovative and significant recent achievements in the fields of ion source physics and technology" (1 page).

  10. Brookhaven National Laboratory/Dale W. Jorgenson Associates long-term energy/economy reference projection

    Energy Technology Data Exchange (ETDEWEB)

    Dorosh, P.A.; Groncki, P.J.; Goettle, R.J. IV; Hudson, E.A.; Lewis, J.A.; Tingley, R.M.; Van Valkenburg, K.

    1981-07-01

    This report summarizes a detailed projection of the growth and structure of the US energy and economic systems for the period 1980 to 2000. The projection originates through use of a combined model system that simulates energy and economic activity under a comprehensive set of assumptions. These assumptions cover a range of demographic, economic, and energy conditions that define the circumstances and constraints influencing the directions of private and public decisions. Accordingly, many of the provisions of current public policy are included among these inputs. The framework employed in this analysis is provided by the linked energy-economy model system of Brookhaven National Laboratory (BNL) and Dale W. Jorgenson Associates (DJA). This projection provides a point of reference for the quantitative analysis of proposed policy measures, research directions, and possible energy and economic contingencies.

  11. Highway accident involving radiopharmaceuticals near Brookhaven, Mississippi on December 3, 1983

    Energy Technology Data Exchange (ETDEWEB)

    Mohr, P.B.; Mount, M.E.; Schwartz, M.W.

    1985-04-01

    A rear-end collision occurred between a passenger automobile and a luggage trailer carrying 84 packages, 76 of which contained radiopharmaceuticals, on US Highway 84 near Brookhaven, Mississippi on the afternoon of December 3, 1983. The purpose of this report is to document the mechanical circumstances of the accident, confirm the nature and quantity of radioactive materials involved, and assess the nature of the physical environment to which the packages were exposed and the response of the packages. The report consists of three major sections. The first deals wth the nature and circumstances of the accident and findings of fact. The second gives an accounting and description of the materials involved and the consequences of their exposure. The third gives an assessment and analysis of the mechanisms of damage and the conclusions which may be drawn from the investigation. 4 refs., 24 figs., 4 tabs.

  12. Structural biology facilities at Brookhaven National Laboratory`s high flux beam reactor

    Energy Technology Data Exchange (ETDEWEB)

    Korszun, Z.R.; Saxena, A.M.; Schneider, D.K. [Brookhaven National Laboratory, Upton, NY (United States)

    1994-12-31

    The techniques for determining the structure of biological molecules and larger biological assemblies depend on the extent of order in the particular system. At the High Flux Beam Reactor at the Brookhaven National Laboratory, the Biology Department operates three beam lines dedicated to biological structure studies. These beam lines span the resolution range from approximately 700{Angstrom} to approximately 1.5{Angstrom} and are designed to perform structural studies on a wide range of biological systems. Beam line H3A is dedicated to single crystal diffraction studies of macromolecules, while beam line H3B is designed to study diffraction from partially ordered systems such as biological membranes. Beam line H9B is located on the cold source and is designed for small angle scattering experiments on oligomeric biological systems.

  13. Radiation dosimetry for NCT facilities at the Brookhaven Medical Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Holden, N.E.; Hu, J.P.; Greenberg, D.D.; Reciniello, R.N.

    1998-12-31

    Brookhaven Medical Research Reactor (BMRR) is a 3 mega-watt (MW) heterogeneous, tank-type, light water cooled and moderated, graphite reflected reactor, which was designed for medical and biological studies and became operational in 1959. Over time, the BMRR was modified to provide thermal and epithermal neutron beams suitable for research studies. NCT studies have been performed at both the epithermal neutron irradiation facility (ENIF) on the east side of the BMRR reactor core and the thermal neutron irradiation facility (TNIF) on the west side of the core. Neutron and gamma-ray dosimetry performed from 1994 to the present in both facilities are described and the results are presented and discussed.

  14. Physics design for the Brookhaven Medical Research Reactor epithermal neutron source.

    Science.gov (United States)

    Wheeler, F J; Parsons, D K; Nigg, D W; Wessol, D E; Miller, L G; Fairchild, R G

    1990-01-01

    A collaborative effort by researchers at the Idaho National Engineering Laboratory and the Brookhaven National Laboratory has resulted in the design and implementation of an epithermal-neutron source at the Brookhaven Medical Research Reactor (BMRR). Large aluminum containers, filled with aluminum oxide tiles and aluminum spacers, were tailored to pre-existing compartments on the animal side of the reactor facility. A layer of cadmium was used to minimize the thermal-neutron component. Additional bismuth was added to the pre-existing bismuth shield to minimize the gamma component of the beam. Lead was also added to reduce gamma streaming around the bismuth. The physics design methods are outlined in this paper. Information available to date shows close agreement between calculated and measured beam parameters. The neutron spectrum is predominantly in the intermediate energy range (0.5 eV - 10 keV). The peak flux intensity is 6.4E + 12 n/(m2.s.MW) at the center of the beam on the outer surface of the final gamma shield. The corresponding neutron current is 3.8E + 12 n/(m2.s.MW). Presently, the core operates at a maximum of 3 MW. The fast-neutron KERMA is 3.6E-15 cGy/(n/m2) and the gamma KERMA is 5.0E-16 cGY/(n/m2) for the unperturbed beam. The neutron intensity falls off rapidly with distance from the outer shield and the thermal flux realized in phantom or tissue is strongly dependent on the beam-delimiter and target geometry.

  15. Twenty years of space radiation physics at the BNL AGS and NASA Space Radiation Laboratory.

    Science.gov (United States)

    Miller, J; Zeitlin, C

    2016-06-01

    Highly ionizing atomic nuclei HZE in the GCR will be a significant source of radiation exposure for humans on extended missions outside low Earth orbit. Accelerators such as the LBNL Bevalac and the BNL AGS, designed decades ago for fundamental nuclear and particle physics research, subsequently found use as sources of GCR-like particles for ground-based physics and biology research relevant to space flight. The NASA Space Radiation Laboratory at BNL was constructed specifically for space radiation research. Here we review some of the space-related physics results obtained over the first 20 years of NASA-sponsored research at Brookhaven.

  16. OVERCOMING DEPOLARIZING RESONANCES IN THE AGS WITH TWO HELICAL PARTIAL SNAKES

    Energy Technology Data Exchange (ETDEWEB)

    HUANG,H.; AHRENS, L.; BAI, M.; BROWN, K.A.; GARDNER, C.J.; ET AL.

    2007-06-25

    Dual partial snake scheme has provided polarized proton beams with 1.5 x 10{sup 11} intensity and 65% polarization for the Relativistic Heavy Ion Collider (RHIC) spin program. To overcome the residual polarization loss due to horizontal resonances in the Brookhaven Alternating Gradient Synchrotron (AGS), a new string of quadrupoles have been added. The horizontal tune can then be set in the spin tune gap generated by the two partial snakes, such that horizontal resonances can also be avoided. This paper presents the accelerator setup and preliminary results.

  17. Interactive radiopharmaceutical facility between Yale Medical Center and Brookhaven National Laboratory. Progress report, October 1976-June 1979

    Energy Technology Data Exchange (ETDEWEB)

    Gottschalk, A.

    1979-01-01

    DOE Contract No. EY-76-S-02-4078 was started in October 1976 to set up an investigative radiochemical facility at the Yale Medical Center which would bridge the gap between current investigation with radionuclides at the Yale School of Medicine and the facilities in the Chemistry Department at the Brookhaven National Laboratory. To facilitate these goals, Dr. Mathew L. Thakur was recruited who joined the Yale University faculty in March of 1977. This report briefly summarizes our research accomplishments through the end of June 1979. These can be broadly classified into three categories: (1) research using indium-111 labelled cellular blood components; (2) development of new radiopharmaceuticals; and (3) interaction with Dr. Alfred Wolf and colleagues in the Chemistry Department of Brookhaven National Laboratory.

  18. Superconducting Helical Snake Magnet for the AGS

    CERN Document Server

    Willen, Erich; Escallier, John; Ganetis, George; Ghosh, Arup; Gupta, Ramesh C; Harrison, Michael; Jain, Animesh K; Luccio, Alfredo U; MacKay, William W; Marone, Andrew; Muratore, Joseph F; Okamura, Masahiro; Plate, Stephen R; Roser, Thomas; Tsoupas, Nicholaos; Wanderer, Peter

    2005-01-01

    A superconducting helical magnet has been built for polarized proton acceleration in the Brookhaven AGS. This "partial Snake" magnet will help to reduce the loss of polarization of the beam due to machine resonances. It is a 3 T magnet some 1940 mm in magnetic length in which the dipole field rotates with a pitch of 0.2053 degrees/mm for 1154 mm in the center and a pitch of 0.3920 degrees/mm for 393 mm in each end. The coil cross-section is made of two slotted cylinders containing superconductor. In order to minimize residual offsets and deflections of the beam on its orbit through the Snake, a careful balancing of the coil parameters was necessary. In addition to the main helical coils, a solenoid winding was built on the cold bore tube inside the main coils to compensate for the axial component of the field that is experienced by the beam when it is off-axis in this helical magnet. Also, two dipole corrector magnets were placed on the same tube with the solenoid. A low heat leak cryostat was built so that t...

  19. Department of Energy’s ARM Climate Research Facility External Data Center Operations Plan Located At Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Cialella, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gregory, L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Lazar, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Liang, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ma, L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tilp, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wagener, R. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-05-01

    The External Data Center (XDC) Operations Plan describes the activities performed to manage the XDC, located at Brookhaven National Laboratory (BNL), for the Department of Energy’s Atmospheric Radiation Measurement (ARM) Climate Research Facility. It includes all ARM infrastructure activities performed by the Data Management and Software Engineering Group (DMSE) at BNL. This plan establishes a baseline of expectation within the ARM Operations Management for the group managing the XDC.

  20. In-situ containment of buried waste at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Dwyer, B.P. [Sandia National Labs., Albuquerque, NM (United States); Heiser, J. [Brookhaven National Lab., Upton, NY (United States); Stewart, W.; Phillips, S. [Applied Geotechnical Engineering and Construction, Inc., Richland, WA (United States)

    1997-12-31

    The primary objective of this project was to further develop close-coupled barrier technology for the containment of subsurface waste or contaminant migration. A close-coupled barrier is produced by first installing a conventional cement grout curtain followed by a thin inner lining of a polymer grout. The resultant barrier is a cement polymer composite that has economic benefits derived from the cement and performance benefits from the durable and chemically resistant polymer layer. The technology has matured from a regulatory investigation of issues concerning barriers and barrier materials to a pilot-scale, multiple individual column injections at Sandia National Labs (SNL) to full scale demonstration. The feasibility of this barrier concept was successfully proven in a full scale {open_quotes}cold test{close_quotes} demonstration at Hanford, WA. Consequently, a full scale deployment of the technology was conducted at an actual environmental restoration site at Brookhaven National Lab (BNL), Long Island, NY. This paper discusses the installation and performance of a technology deployment implemented at OU-1 an Environmental Restoration Site located at BNL.

  1. Effect of the solenoid in various conditions of the laser ion source at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, S., E-mail: ikeda.s.ae@m.titech.ac.jp [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Yokohama, Kanagawa 216-8502 (Japan); Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0108 (Japan); Kumaki, M. [Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0108 (Japan); Kanesue, T.; Okamura, M. [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)

    2016-02-15

    In the laser ion source (LIS) at the Brookhaven National Laboratory (BNL), a solenoid is used to guide the laser ablation plasma and modulate the extracted beam current. Many types of ion species are guided. In some cases, the plasma plume is injected into the solenoid away from the solenoidal axis. To investigate the effects of the solenoid on the beam extracted from the plasma that has different properties, the beam current was measured in the setup of the LIS at the BNL. The beam current of Li, Al, Si, Fe, and Au increased when the magnetic field was applied. For most of the species the peak current and the total charge within a single beam pulse increased around 10 times with a magnetic field less than 100 G. In addition, for some species the rate of increase of the peak currents became smaller when the magnetic flux densities were larger than certain values depending on the species. In this case, the current waveforms were distorted. At the same magnetic field value, the field was more effective on lighter species than on heavier ones. When plasma was injected offset from the axis of the solenoid, peak current and total charge became half of those without offset. The experimental data are useful for the operation of the LIS at the BNL.

  2. Effect of the solenoid in various conditions of the laser ion source at Brookhaven National Laboratory

    Science.gov (United States)

    Ikeda, S.; Kumaki, M.; Kanesue, T.; Okamura, M.

    2016-02-01

    In the laser ion source (LIS) at the Brookhaven National Laboratory (BNL), a solenoid is used to guide the laser ablation plasma and modulate the extracted beam current. Many types of ion species are guided. In some cases, the plasma plume is injected into the solenoid away from the solenoidal axis. To investigate the effects of the solenoid on the beam extracted from the plasma that has different properties, the beam current was measured in the setup of the LIS at the BNL. The beam current of Li, Al, Si, Fe, and Au increased when the magnetic field was applied. For most of the species the peak current and the total charge within a single beam pulse increased around 10 times with a magnetic field less than 100 G. In addition, for some species the rate of increase of the peak currents became smaller when the magnetic flux densities were larger than certain values depending on the species. In this case, the current waveforms were distorted. At the same magnetic field value, the field was more effective on lighter species than on heavier ones. When plasma was injected offset from the axis of the solenoid, peak current and total charge became half of those without offset. The experimental data are useful for the operation of the LIS at the BNL.

  3. Reliable operation of the Brookhaven EBIS for highly charged ion production for RHIC and NSRL

    Science.gov (United States)

    Beebe, E.; Alessi, J.; Binello, S.; Kanesue, T.; McCafferty, D.; Morris, J.; Okamura, M.; Pikin, A.; Ritter, J.; Schoepfer, R.

    2015-01-01

    An Electron Beam Ion Source for the Relativistic Heavy Ion Collider (RHIC EBIS) was commissioned at Brookhaven in September 2010 and since then it routinely supplies ions for RHIC and NASA Space Radiation Laboratory (NSRL) as the main source of highly charged ions from Helium to Uranium. Using three external primary ion sources for 1+ injection into the EBIS and an electrostatic injection beam line, ion species at the EBIS exit can be switched in 0.2 s. A total of 16 different ion species have been produced to date. The length and the capacity of the ion trap have been increased by 20% by extending the trap by two more drift tubes, compared with the original design. The fraction of Au32+ in the EBIS Au spectrum is approximately 12% for 70-80% electron beam neutralization and 8 pulses operation in a 5 Hertz train and 4-5 s super cycle. For single pulse per super cycle operation and 25% electron beam neutralization, the EBIS achieves the theoretical Au32+ fractional output of 18%. Long term stability has been very good with availability of the beam from RHIC EBIS during 2012 and 2014 RHIC runs approximately 99.8%.

  4. Doses delivered to normal brain under different treatment protocols at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Capala, J.; Coderre, J.A.; Liu, H.B. [and others

    1996-12-31

    As of October 31, 1996, 23 glioblastoma multiforme patients underwent BNCT under several treatment protocols at the Brookhaven Medical Research Reactor. For treatment planning and dosimetry purposes, these protocols may be divided into four groups. The first group comprises protocols that used an 8-cm collimator and allowed a peak normal brain dose of 10.5 Gy-Eq to avolume of 1 cm{sup 3} were the thermal neutron flux was maximal (even if it happened to be in the tumor volume). The second group differs from the first in that it allowed a peak normal brain dose of 12.6 Gy-Eq. The protocols of the third and fourth groups allowed the prescribed peak normal brain dose of 12.6 Gy-Eq to be outside of the tumor volume, used a 12-cm collimator and, respectively, uni- or bilateral irradiations. We describe the treatment planning procedures and report the doses delivered to various structures of the brain.

  5. Reliable operation of the Brookhaven EBIS for highly charged ion production for RHIC and NSRL

    Energy Technology Data Exchange (ETDEWEB)

    Beebe, E., E-mail: beebe@bnl.gov; Alessi, J., E-mail: beebe@bnl.gov; Binello, S., E-mail: beebe@bnl.gov; Kanesue, T., E-mail: beebe@bnl.gov; McCafferty, D., E-mail: beebe@bnl.gov; Morris, J., E-mail: beebe@bnl.gov; Okamura, M., E-mail: beebe@bnl.gov; Pikin, A., E-mail: beebe@bnl.gov; Ritter, J., E-mail: beebe@bnl.gov; Schoepfer, R., E-mail: beebe@bnl.gov [Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2015-01-09

    An Electron Beam Ion Source for the Relativistic Heavy Ion Collider (RHIC EBIS) was commissioned at Brookhaven in September 2010 and since then it routinely supplies ions for RHIC and NASA Space Radiation Laboratory (NSRL) as the main source of highly charged ions from Helium to Uranium. Using three external primary ion sources for 1+ injection into the EBIS and an electrostatic injection beam line, ion species at the EBIS exit can be switched in 0.2 s. A total of 16 different ion species have been produced to date. The length and the capacity of the ion trap have been increased by 20% by extending the trap by two more drift tubes, compared with the original design. The fraction of Au{sup 32+} in the EBIS Au spectrum is approximately 12% for 70-80% electron beam neutralization and 8 pulses operation in a 5 Hertz train and 4-5 s super cycle. For single pulse per super cycle operation and 25% electron beam neutralization, the EBIS achieves the theoretical Au{sup 32+} fractional output of 18%. Long term stability has been very good with availability of the beam from RHIC EBIS during 2012 and 2014 RHIC runs approximately 99.8%.

  6. The Shape and Flow of Heavy Ion Collisions (490th Brookhaven Lecture)

    Energy Technology Data Exchange (ETDEWEB)

    Schenke, Bjoern [BNL Physics Department

    2014-12-18

    The sun can’t do it, but colossal machines like the Relativistic Heavy Ion Collider (RHIC) at Brookhaven Lab and Large Hadron Collider (LHC) in Europe sure can. Quarks and gluons make up protons and neutrons found in the nucleus of every atom in the universe. At heavy ion colliders like RHIC and the LHC, scientists can create matter more than 100,000 times hotter than the center of the sun—so hot that protons and neutrons melt into a plasma of quarks and gluons. The particle collisions and emerging quark-gluon plasma hold keys to understanding how these fundamental particles interact with each other, which helps explain how everything is held together—from atomic nuclei to human beings to the biggest stars—how all matter has mass, and what the universe looked like microseconds after the Big Bang. Dr. Schenke discusses theory that details the shape and structure of heavy ion collisions. He will also explain how this theory and data from experiments at RHIC and the LHC are being used to determine properties of the quark-gluon plasma.

  7. A Really Good Hammer: Quantification of Mass Transfer Using Perfluorocarbon Tracers (475th Brookhaven Lecture)

    Energy Technology Data Exchange (ETDEWEB)

    Watson, Tom [BNL Environmental Sciences, Tracer Technology Group

    2012-02-15

    Brookhaven Lab’s perfluorocarbon tracer (PFT) technology can be viewed as a hammer looking for nails. But, according to Tom Watson, leader of the Lab’s Tracer Technology Group in the Environmental Research and Technology Division (ERTD), “It’s a really good hammer!” The colorless, odorless and safe gases have a number of research uses, from modeling how airborne contaminants might move through urban canyons to help first responders plan their response to potential terrorist attacks and accidents to locating leaks in underground gas pipes. Their extremely low background level — detectable at one part per quadrillion — allows their transport to be easily tracked. Lab researchers used PFTs during the 2005 Urban Dispersion Program field studies in New York City, gathering data to help improve models of how a gas or chemical release might move around Manhattan’s tall buildings and canyons. Closer to home, scientists also used PFTs to make ventilation measurements in Bldg. 400 on the Lab site to provide data to test air flow models used in determining the effects of passive and active air exchange on the levels of indoor and outdoor air pollution, and to determine the effects of an accidental or intentional release of hazardous substances in or around buildings.

  8. Status of high current R&D Energy Recovery LINAC at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Kayran, D.; Altinbas Z.; Beavis D.; Ben-Zvi I.; Calaga R.; Gassner D.M.; Hahn H.; Hammons L.; Jain A.; Jamilkowski J.; Lambiase R.; Lederle D.; Litvinenko V.N.; Laloudakis N.; Mahler G.; McIntyre G.; Meng W.; Oerter B.; Pate D.; Phillips D.; Reich J.; Roser T.; Schultheiss C.; Seda T.; Sheehy B.; Srinivasan-Rao T.; Than R.; Tuozzolo J.; Weiss D.; Xu W.; Zaltsman A.

    2011-03-28

    An ampere class 20 MeV superconducting Energy Recovery Linac (ERL) is under construction at Brookhaven National Laboratory (BNL) for testing of concepts relevant for high-energy coherent electron cooling and electron-ion colliders. One of the goals is to demonstrate an electron beam with high charge per bunch ({approx} 5 nC) and low normalized emittance ({approx} 5 mm-mrad) at an energy of 20 MeV. Flexible lattice of ERL loop provides a test-bed for investigating issues of transverse and longitudinal instabilities, and diagnostics for intense CW e-beam. The superconducting 703 MHz RF photoinjector is considered as an electron source for such a facility. We will start with a straight pass (gun - 5 cell cavity - beam stop) test for the SRF Gun performance studies. Later, we will install and test a novel injection line concept for emittance preservation in a lower energy merger. In this paper we present the status and our plans for construction and commissioning of this facility.

  9. Brookhaven solar-heat-pump simulator: technical description and experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Catan, M.

    1982-07-01

    The series solar-assisted heat pump (SAHP) system has the potential to deliver heat with very high seasonal coefficients of performance (coefficient of performance or COP is the ratio of useful heat delivered to electrical power consumed). This potential rests on the ability of the heat-pump component to use the high source temperatures available from the solar-collector component to deliver heat with a COP which rises monotonically with source temperature. The Brookhaven National Laboratory (BNL) Heat Pump Simulator has played an important role in a program aimed at demonstrating the feasibility of building simple potentially inexpensive heat pumps for use in SAHP systems. Basically the work described here consists of the following: (1) The construction and testing of a laboratory heat pump built from conventional components and characterized by a very desirable COP versus source temperature profile. (2) The testing of two prototype SAHPs built by heat-pump manufacturers under contract to DOE. (3) Detailed component and control tests aimed at establishing improvements in the SAHP prototypes. The paper describes, in some detail, the BNL Heat Pump Simulator, a versatile instrument used to test heat pumps and heat-pump subcomponents under transient and steady-state conditions.

  10. What Goes Up Must Come Down: The Lifecycle of Convective Clouds (492nd Brookhaven Lecture)

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Michael [BNL Environmental Sciences

    2014-02-19

    Some clouds look like cotton balls and others like anvils. Some bring rain, some snow and sleet, and others, just shade. But, whether big and billowy or dark and stormy, clouds affect far more than the weather each day. Armed with measurements of clouds’ updrafts and downdrafts—which resemble airflow in a convection oven—and many other atmospheric interactions, scientists from Brookhaven Lab and other institutions around the world are developing models that are crucial for understanding Earth’s climate and forecasting future climate change. During his lecture, Dr. Jensen provides an overview of the importance of clouds in the Earth’s climate system before explaining how convective clouds form, grow, and dissipate. His discussion includes findings from the Midlatitude Continental Convective Clouds Experiment (MC3E), a major collaborative experiment between U.S. Department of Energy (DOE) and NASA scientists to document precipitation, clouds, winds, and moisture in 3-D for a holistic view of convective clouds and their environment.

  11. 915-MHz Wind Profiler for Cloud Forecasting at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Bartholomew, M. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Giangrande, S. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-03-01

    When considering the amount of shortwave radiation incident on a photovoltaic solar array and, therefore, the amount and stability of the energy output from the system, clouds represent the greatest source of short-term (i.e., scale of minutes to hours) variability through scattering and reflection of incoming solar radiation. Providing estimates of this short-term variability is important for determining and regulating the output from large solar arrays as they connect with the larger power infrastructure. In support of the installation of a 37-MW solar array on the grounds of Brookhaven National Laboratory (BNL), a study of the impacts of clouds on the output of the solar array has been undertaken. The study emphasis is on predicting the change in surface solar radiation resulting from the observed/forecast cloud field on a 5-minute time scale. At these time scales, advection of cloud elements over the solar array is of particular importance. As part of the BNL Aerosol Life Cycle Intensive Operational Period (IOP), a 915-MHz Radar Wind Profiler (RWP) was deployed to determine the profile of low-level horizontal winds and the depth of the planetary boundary layer. The initial deployment mission of the 915-MHz RWP for cloud forecasting has been expanded the deployment to provide horizontal wind measurements for estimating and constraining cloud advection speeds. A secondary focus is on the observation of dynamics and microphysics of precipitation during cold season/winter storms on Long Island. In total, the profiler was deployed at BNL for 1 year from May 2011 through May 2012.

  12. 915-Mhz Wind Profiler for Cloud Forecasting at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, M. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Bartholomew, M. J. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Giangrande, S. [Brookhaven National Laboratory (BNL), Upton, NY (United States)

    2016-03-01

    When considering the amount of shortwave radiation incident on a photovoltaic solar array and, therefore, the amount and stability of the energy output from the system, clouds represent the greatest source of short-term (i.e., scale of minutes to hours) variability through scattering and reflection of incoming solar radiation. Providing estimates of this short-term variability is important for determining and regulating the output from large solar arrays as they connect with the larger power infrastructure. In support of the installation of a 37-MW solar array on the grounds of Brookhaven National Laboratory (BNL), a study of the impacts of clouds on the output of the solar array has been undertaken. The study emphasis is on predicting the change in surface solar radiation resulting from the observed/forecast cloud field on a 5-minute time scale. At these time scales, advection of cloud elements over the solar array is of particular importance. As part of the BNL Aerosol Life Cycle Intensive Operational Period (IOP), a 915-MHz Radar Wind Profiler (RWP) was deployed to determine the profile of low-level horizontal winds and the depth of the planetary boundary layer. The initial deployment mission of the 915-MHz RWP for cloud forecasting has been expanded the deployment to provide horizontal wind measurements for estimating and constraining cloud advection speeds. A secondary focus is on the observation of dynamics and microphysics of precipitation during cold season/winter storms on Long Island. In total, the profiler was deployed at BNL for 1 year from May 2011 through May 2012.

  13. Radar Wind Profiler for Cloud Forecasting at Brookhaven National Laboratory (BNL) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, M. P. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Giangrande, S. E. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Bartholomew, M. J. [Brookhaven National Laboratory (BNL), Upton, NY (United States)

    2016-04-01

    The Radar Wind Profiler for Cloud Forecasting at Brookhaven National Laboratory (BNL) [http://www.arm.gov/campaigns/osc2013rwpcf] campaign was scheduled to take place from 15 July 2013 through 15 July 2015 (or until shipped for the next U.S. Department of Energy Atmospheric Radiation Measurement [ARM] Climate Research Facility first Mobile Facility [AMF1] deployment). The campaign involved the deployment of the AMF1 Scintec 915 MHz Radar Wind Profiler (RWP) at BNL, in conjunction with several other ARM, BNL and National Weather Service (NWS) instruments. The two main scientific foci of the campaign were: 1) To provide profiles of the horizontal wind to be used to test and validate short-term cloud advection forecasts for solar-energy applications and 2) to provide vertical profiling capabilities for the study of dynamics (i.e., vertical velocity) and hydrometeors in winter storms. This campaign was a serendipitous opportunity that arose following the deployment of the RWP at the Two-Column Aerosol Project (TCAP) campaign in Cape Cod, Massachusetts and restriction from participation in the Green Ocean Amazon 2014/15 (GoAmazon 2014/15) campaign due to radio-frequency allocation restriction for international deployments. The RWP arrived at BNL in the fall of 2013, but deployment was delayed until fall of 2014 as work/safety planning and site preparation were completed. The RWP further encountered multiple electrical failures, which eventually required several shipments of instrument power supplies and the final amplifier to the vendor to complete repairs. Data collection began in late January 2015. The operational modes of the RWP were changed such that in addition to collecting traditional profiles of the horizontal wind, a vertically pointing mode was also included for the purpose of precipitation sensing and estimation of vertical velocities. The RWP operated well until the end of the campaign in July 2015 and collected observations for more than 20 precipitation

  14. Study of quark flow in exclusive reactions at 90 degrees in the center of mass (AGS E838)

    Science.gov (United States)

    Appel, R.; White, C.; Courant, H.; Fang, G.; Heller, K. J.; Johns, K.; Marshak, M. L.; Shupe, M.; Barton, D. S.; Bunce, G.; Carroll, A. S.; Gushue, S.; Kmit, M.; Lowenstein, D. I.; Makdisi, Y. I.; Heppelmann, S.; Ma, X.; Russell, J. J.

    1995-07-01

    We report a study of quark flow in 20 exclusive reactions measured at Brookhaven National Laboratory's AGS with a beam momentum of 5.9 GeV/c at 90° in the center of mass. This experiment confirms the strong quark flow reaction mechanism dependence of two-body hadron scattering at large angles seen at 9.9 GeV/c. Large differences in cross sections for different reactions are consistent with the dominance of quark interchange in these 90° reactions, and indicate that pure gluon exchange and quark/antiquark annihilation diagrams are less important.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-12-15

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

  16. SIMULATIONS OF THE AGS MMPS STORING ENERGY IN CAPACITOR BANKS

    Energy Technology Data Exchange (ETDEWEB)

    MARNERIS,I.; BADEA, V.S.; BONATI, R.; ROSER, T.; SANDBERG, J.

    2007-06-25

    The Brookhaven AGS Main Magnet Power Supply (MMPS) is a thyristor control supply rated at 5500 Amps, +/-9000 Volts. The peak magnet power is 50 MWatts. The power supply is fed from a motor/generator manufactured by Siemens. The generator is 3 phase 7500 Volts rated at 50 MVA. The peak power requirements come from the stored energy in the rotor of the motor/generator. The motor generator is about 45 years old, made by Siemens and it is not clear if companies will be manufacturing similar machines in the future. We are therefore investigating different ways of storing energy for future AGS MMPS operations. This paper will present simulations of a power supply where energy is stored in capacitor banks. Two dc to dc converters will be presented along with the control system of the power section. The switching elements will be IGCT's made by ABB. The simulation program used is called PSIM version 6.1. The average power from the local power authority into the power supply will be kept constant during the pulsing of the magnets at +/-50 MW. The reactive power will also be kept constant below 1.5 MVAR. Waveforms will be presented.

  17. Proceedings of RIKEN BNL Research Center Workshop: Brookhaven Summer Program on Nucleon Spin Physics

    Energy Technology Data Exchange (ETDEWEB)

    Aschenauer, A.; Qiu, Jianwei; Vogelsang, W.; Yuan, F.

    2011-08-02

    Understanding the structure of the nucleon is of fundamental importance in sub-atomic physics. Already the experimental studies on the electro-magnetic form factors in the 1950s showed that the nucleon has a nontrivial internal structure, and the deep inelastic scattering experiments in the 1970s revealed the partonic substructure of the nucleon. Modern research focuses in particular on the spin and the gluonic structure of the nucleon. Experiments using deep inelastic scattering or polarized p-p collisions are carried out in the US at the CEBAF and RHIC facilities, respectively, and there are other experimental facilities around the world. More than twenty years ago, the European Muon Collaboration published their first experimental results on the proton spin structure as revealed in polarized deep inelastic lepton-nucleon scattering, and concluded that quarks contribute very little to the proton's spin. With additional experimental and theoretical investigations and progress in the following years, it is now established that, contrary to naive quark model expectations, quarks and anti-quarks carry only about 30% of the total spin of the proton. Twenty years later, the discovery from the polarized hadron collider at RHIC was equally surprising. For the phase space probed by existing RHIC experiments, gluons do not seem to contribute any to the proton's spin. To find out what carries the remaining part of proton's spin is a key focus in current hadronic physics and also a major driving force for the new generation of spin experiments at RHIC and Jefferson Lab and at a future Electron Ion Collider. It is therefore very important and timely to organize a series of annual spin physics meetings to summarize the status of proton spin physics, to focus the effort, and to layout the future perspectives. This summer program on 'Nucleon Spin Physics' held at Brookhaven National Laboratory (BNL) on July 14-27, 2010 [http://www.bnl.gov/spnsp/] is the

  18. AGS experiments: 1993 - 1994 - 1995

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1996-04-01

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

  19. Summary update of the Brookhaven tritium toxicity program with emphasis on recent cytogenetic and lifetime-shortening studies

    Energy Technology Data Exchange (ETDEWEB)

    Carsten, A.L.; Benz, R.D.; Hughes, W.P.; Ichimasa, Yusuke; Ikushima, Takaji; Tezuka, Hideo

    1988-01-01

    A number of years ago a multiparameter program to evaluate the toxicity of tritiated water (HTO) was undertaken in the Medical Department at Brookhaven National Laboratory. The results of most of these studies have been published and will receive brief attention. Emphasis will be placed on the unpublished studies involving the induction of sister chromatid exchanges (SCE's) in bone marrow of mice, new biochemical information, and preliminary results on lifetime-shortening and carcinogenesis. In brief, male Hale-Stoner Brookhaven (HSB) mice maintained on HTO concentrations ranging from 3.0 to 30.0 ..mu..Ci/ml exhibited essentially the same number of SCE's per cell throughout their lifetime. Control mice showed a decrease in number of SCE's with age. The lack of a dose-response effect and the constant level of SCE's in HTO mice as compared to controls will be discussed. In the carcinogenesis study C57BL/6J male mice received various x-ray or HTO regimens. Mortality data from these and other studies in which CBA/Ca/BNL mice received single x-ray exposures or equivalent integrated dose exposures by single HTO injections will be discussed. 25 refs., 4 figs.

  20. Direct Comparison of Brookhaven Reflectivity Measurements with Free-Electron Theory

    Energy Technology Data Exchange (ETDEWEB)

    Bane, Karl L.F.

    2010-12-13

    The reflectivity at normal incidence of copper and aluminum samples was recently measured over a large frequency range at Brookhaven by one of us (JT). Then using the Kramers-Kroning integrals, and assuming the free-electron model of conductivity, the dependence of conductivity on frequency was obtained. The results seemed to suggest, for example, that the dc conductivities of the copper and evaporated aluminum samples are a factor of 3 lower than expected. We propose in this report, instead, directly fitting the free-electron model to the low frequency end of the reflectivity data. This fitting does not depend on the higher frequency results and on Kramers-Kronig integrations, but it does assume that the data at the low frequency end is sufficiently accurate. Note that for our LCLS wakefield studies, it is only over these (relatively) low frequencies that we need to know the electrical properties of the metals. The equations that relate reflectivity R with the free electron parameters dc conductivity {sigma} and relaxation time {tau} are: (1) {tilde {sigma}} = {sigma}/1-ikc{tau}; (2) {tilde n} = {radical} {tilde {epsilon}} = {radical}(1+4{pi}i{tilde k}c/{omega}); and (3) R = |{tilde n}-1/{tilde n} + 1|{sup 2}. The parameters are ac conductivity {tilde {sigma}}, index of refraction {tilde n}, dielectric constant {tilde {epsilon}}, and wave number k = {omega}/c, with {omega} frequency and c the speed of light. In Fig. 1 we show the ideal behavior of R for a reasonably good conducting metal, where {sigma} = 0.12 x 10{sup 17}/s and {tau} = 0.55 x 10{sup -14} s (solid line); these parameters are, respectively, 2% ({sigma}) and 20% ({tau}) of the nominal values for copper. The parameters were chosen so that the important features of R(k) could be seen easily in one plot. We see 3 distinct regions: (1) for low frequencies, k {approx}< 1/c{tau}, R continually decreases, with positive curvature, and with a low frequency asymptote of (1 - {radical}2kc/{pi}{sigma}); (2) for

  1. Ground-water quality and geochemical processes at a municipal landfill, Town of Brookhaven, Long Island, New York

    Science.gov (United States)

    Pearsall, Kenneth A.; Aufderheide, Mary Jean

    1995-01-01

    The principal geochemical process within a plume of leachate-contaminated ground water downgradient from the municipal landfill in the Town of Brookhaven is the oxidation of organic matter. Concurrent reducing processes are the reduction of iron and manganese oxyhydroxides to soluble ferrous and manganous forms, of nitrate and nitrite to nitrogen and ammonia, of sulfate to sulfide (sulfide precipitates from solution as iron and manganese sulfides), and, under extreme conditions, of some organic matter to methane. Secondary processes unrelated to bacterial activity and redox processes are the exchange of dissolved sodium and potassium for calcium and magnesium at ion-exchange sites and the dissolution of calcium and magnesium silicate minerals; these processes cause sodium and potassium concentrations to decrease with depth and with distance from the landfill and cause calcium, magnesium, and silica concentrations to increase.

  2. Optimization of the Epithermal Neutron Beam for Boron Neutron Capture Therapy at the Brookhaven Medical Research Reactor

    Science.gov (United States)

    Hu, Jih-Perng; Rorer, David C.; Reciniello, Richard N.; Holden, Norman E.

    2003-06-01

    Clinical trials of Boron Neutron Capture Therapy for patients with malignant brain tumor had been carried out for half a decade, using an epithermal neutron beam at the Brookhaven Medical Reactor. The decision to permanently close this reactor in 2000 cut short the efforts to implement a new conceptual design to optimize this beam in preparation for use with possible new protocols. Details of the conceptual design to produce a higher intensity, more forward-directed neutron beam with less contamination from gamma rays, fast and thermal neutrons are presented here for their potential applicability to other reactor facilities. Monte Carlo calculations were used to predict the flux and absorbed dose produced by the proposed design. The results were benchmarked by the dose rate and flux measurements taken at the facility then in use.

  3. Optimization of the epithermal neutron beam for Boron Neutron Capture Therapy at the Brookhaven Medical Research Reactor.

    Science.gov (United States)

    Hu, Jih-Perng; Reciniello, Richard N; Holden, Norman E

    2004-05-01

    The use of epithermal neutron beam in clinical trials of Boron Neutron Capture Therapy for patients with malignant brain tumors had been carried out for half a decade at the Brookhaven's Medical Reactor. The decision to permanently close this reactor in 2000 cut short the efforts to implement a new conceptual design to optimize this beam in preparation for use with possible new BNCT protocols. Details of the conceptual design to produce a highly intensified and focused neutron beam with less gamma and neutron contamination in tissues are presented here for their potential applicability to other reactor facilities. Neutron-photon coupled Monte Carlo calculations were used to predict the flux, current, heating, and absorbed dose produced by the proposed design. The results were benchmarked by the dose rate and flux measurements taken at the facility then in use.

  4. Risk assessment and optimization (ALARA) analysis for the environmental remediation of Brookhaven National Laboratory`s hazardous waste management facility

    Energy Technology Data Exchange (ETDEWEB)

    Dionne, B.J.; Morris, S.C. III; Baum, J.W. [and others

    1998-01-01

    The Department of Energy`s (DOE) Office of Environment, Safety, and Health (EH) sought examples of risk-based approaches to environmental restoration to include in their guidance for DOE nuclear facilities. Extensive measurements of radiological contamination in soil and ground water have been made at Brookhaven National Laboratory`s Hazardous Waste Management Facility (HWMF) as part of a Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) remediation process. This provided an ideal opportunity for a case study. This report provides a risk assessment and an {open_quotes}As Low as Reasonably Achievable{close_quotes} (ALARA) analysis for use at other DOE nuclear facilities as an example of a risk-based decision technique. This document contains the Appendices for the report.

  5. Risk assessment and optimization (ALARA) analysis for the environmental remediation of Brookhaven National Laboratory`s hazardous waste management facility

    Energy Technology Data Exchange (ETDEWEB)

    Dionne, B.J.; Morris, S. III; Baum, J.W. [and others

    1998-03-01

    The Department of Energy`s (DOE) Office of Environment, Safety, and Health (EH) sought examples of risk-based approaches to environmental restoration to include in their guidance for DOE nuclear facilities. Extensive measurements of radiological contamination in soil and ground water have been made at Brookhaven National Laboratory`s Hazardous Waste Management Facility (HWMF) as part of a Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) remediation process. This provided an ideal opportunity for a case study. This report provides a risk assessment and an {open_quotes}As Low as Reasonably Achievable{close_quotes} (ALARA) analysis for use at other DOE nuclear facilities as an example of a risk-based decision technique.

  6. A service-based SLA (Service Level Agreement) for the RACF (RHIC and ATLAS computing facility) at brookhaven national lab

    Science.gov (United States)

    Karasawa, Mizuka; Chan, Tony; Smith, Jason

    2010-04-01

    The RACF provides computing support to a broad spectrum of scientific programs at Brookhaven. The continuing growth of the facility, the diverse needs of the scientific programs and the increasingly prominent role of distributed computing requires the RACF to change from a system to a service-based SLA with our user communities. A service-based SLA allows the RACF to coordinate more efficiently the operation, maintenance and development of the facility by mapping out a matrix of system and service dependencies and by creating a new, configurable alarm management layer that automates service alerts and notification of operations staff. This paper describes the adjustments made by the RACF to transition to a service-based SLA, including the integration of its monitoring software, alarm notification mechanism and service ticket system at the facility to make the new SLA a reality.

  7. Design and Fabrication of a Highly Integrated Silicon Detector for the STAR Experiment at Brookhaven National Laboratory

    CERN Document Server

    Buck, Benjamin; Bessuille, Jason; Cepeda, Mario; Johnson, Thomas; Kelsey, James; van Nieuwenhuizen, Gerrit; Visser, Gerard

    2014-01-01

    We present the design of a detector used as a particle tracking device in the STAR experiment at the RHIC collider of Brookhaven National Laboratories. The "stave," 24 of which make up the completed detector, is a highly mechanically integrated design comprised of 6 custom silicon sensors mounted on a Kapton substrate. 4608 wire bonds connect these sensors to 36 analog front-end chips which are mounted on the same substrate. Power and signal connectivity from the hybrid to the front-end chips is provided by wire bonds. The entire circuit is mounted on a carbon fiber base co-cured to the Kapton substrate. We present the unique design challenges for this detector and some novel techniques for overcoming them.

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

    Science.gov (United States)

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

    2013-03-01

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

  9. The first moment of azimuthal anisotropy in nuclear collisions from AGS to LHC energies

    CERN Document Server

    Singha, Subhash; Keane, Declan

    2016-01-01

    We review topics related to the first moment of azimuthal anisotropy ($v_1$), commonly known as directed flow, focusing on both charged particles and identified particles from heavy-ion collisions. Beam energies from the highest available, at the CERN LHC, down to projectile kinetic energies per nucleon of a few GeV per nucleon, as studied in experiments at the Brookhaven AGS, fall within our scope. We focus on experimental measurements and on theoretical work where direct comparisons with experiment have been emphasized. The physics addressed or potentially addressed by this review topic includes the study of Quark Gluon Plasma, and more generally, investigation of the Quantum Chromodynamics phase diagram and the equation of state describing the accessible phases.

  10. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

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

  11. AGS Booster prototype magnets

    Energy Technology Data Exchange (ETDEWEB)

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

    1987-03-19

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1994-04-01

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

  13. AGS experiments -- 1995, 1996 and 1997

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-12-01

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

  14. Design of a high-flux epithermal neutron beam using 235U fission plates at the Brookhaven Medical Research Reactor.

    Science.gov (United States)

    Liu, H B; Brugger, R M; Rorer, D C; Tichler, P R; Hu, J P

    1994-10-01

    Beams of epithermal neutrons are being used in the development of boron neutron capture therapy for cancer. This report describes a design study in which 235U fission plates and moderators are used to produce an epithermal neutron beam with higher intensity and better quality than the beam currently in use at the Brookhaven Medical Research Reactor (BMRR). Monte Carlo calculations are used to predict the neutron and gamma fluxes and absorbed doses produced by the proposed design. Neutron flux measurements at the present epithermal treatment facility (ETF) were made to verify and compare with the computed results where feasible. The calculations indicate that an epithermal neutron beam produced by a fission-plate converter could have an epithermal neutron intensity of 1.2 x 10(10) n/cm2.s and a fast neutron dose per epithermal neutron of 2.8 x 10(-11) cGy.cm2/nepi plus being forward directed. This beam would be built into the beam shutter of the ETF at the BMRR. The feasibility of remodeling the facility is discussed.

  15. Comparative Analysis of Brookhaven National Laboratory Nuclear Decay Data and Super-Kamiokande Neutrino Data: Indication of a Solar Connection

    CERN Document Server

    Sturrock, P A

    2015-01-01

    An experiment carried out at the Brookhaven National Laboratory from February 1982 to December 1989 acquired 364 measurements of the beta-decay rates of a sample of 36Cl and of a sample of 32Si. The experimenters reported finding small periodic annual deviations of the data points from an exponential decay - of uncertain origin. We here analyze this dataset by power spectrum analysis and by forming spectrograms and phasegrams. We confirm the occurrence of annual oscillations but we also find evidence of oscillations in a band of frequencies appropriate for the internal rotation of the Sun. Both datasets show clear evidence of a transient oscillation with a frequency of 12.7 cycles per year that falls in the range of rotational frequencies for the solar radiative zone. We repeat these analyses for 358 neutrino measurements acquired by Super-Kamiokande over the interval May 1986 to August 2001. Spectrogram analysis yields a strong and steady oscillation at about 9.5 cycles per year and an intermittent oscillati...

  16. Ag transport in CrN-Ag nanocomposite coatings

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-09-01

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

  17. THE AGS-BASED SUPER NEUTRINO BEAM FACILITY CONCEPTUAL DESIGN REPORT

    Energy Technology Data Exchange (ETDEWEB)

    WENG,W.T.; DIWAN,M.; RAPARIA,D.

    2004-10-08

    After more than 40 years of operation, the AGS is still at the heart of the Brookhaven hadron accelerator complex. This system of accelerators presently comprises a 200 MeV linac for the pre-acceleration of high intensity and polarized protons, two Tandem Van der Graaffs for the pre-acceleration of heavy ion beams, a versatile Booster that allows for efficient injection of all three types of beams into the AGS and, most recently, the two RHIC collider rings that produce high luminosity heavy ion and polarized proton collisions. For several years now, the AGS has held the world intensity record with more than 7 x 10{sup 13} protons accelerated in a single pulse. The requirements for the proton beam for the super neutrino beam are summarized and a schematic of the upgraded AGS is shown. Since the present number of protons per fill is already close to the required number, the upgrade is based on increasing the repetition rate and reducing beam losses (to avoid excessive shielding requirements and to maintain activation of the machine components at workable level). It is also important to preserve all the present capabilities of the AGS, in particular its role as injector to RHIC. The AGS Booster was built not only to allow the injection of any species of heavy ion into the AGS but to allow a fourfold increase of the AGS intensity. It is one-quarter the circumference of the AGS with the same aperture. However, the accumulation of four Booster loads in the AGS takes about 0.6 s, and is therefore not well suited for high average beam power operation. To minimize the injection time to about 1 ms, a 1.2 GeV linac will be used instead. This linac consists of the existing warm linac of 200 MeV and a new superconducting linac of 1.0 GeV. The multi-turn H{sup -} injection from a source of 30 mA and 720 {micro}s pulse width is sufficient to accumulate 9 x 10{sup 13} particle per pulse in the AGS[10]. The minimum ramp time of the AGS to full energy is presently 0.5 s; this must

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

    Science.gov (United States)

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

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

  19. CSEWG SYMPOSIUM, A CSWEG RETROSPECTIVE. 35TH ANNIVERSARY CROSS SECTION EVALUATION WORKING GROUP, NOV. 5, 2001, BROOKHAVEN NATIONAL LABORATORY.

    Energy Technology Data Exchange (ETDEWEB)

    DUNFORD, C.; HOLDEN, N.; PEARLSTEIN, S.

    2001-11-05

    This publication has been prepared to record some of the history of the Cross Section Evaluation Working Group (CSEWG). CSEWG is responsible for creating the evaluated nuclear data file (ENDF/B) which is widely used by scientists and engineers who are involved in the development and maintenance of applied nuclear technologies. This organization has become the model for the development of nuclear data libraries throughout the world. The data format (ENDF) has been adopted as the international standard. On November 5, 2001, a symposium was held at Brookhaven National Laboratory to celebrate the 50 th meeting of the CSEWG organization and the 35 th anniversary of its first meeting in November 1966. The papers presented in this volume were prepared by present and former CSEWG members for presentation at the November 2001 symposium. All but two of the presentations are included. I have included an appendix to list all of the CSEWG members and their affiliations, which has been compiled from the minutes of each of the CSEWG meetings. Minutes exist for all meetings except the 4 th meeting held in January 1968. The list includes 348 individuals from 71 organizations. The dates for each of the 50 CSEWG meetings are listed. The committee structure and chairmen of all committees and subcommittees are also included in the appendix. This volume is dedicated to three individuals whose foresight and talents made CSEWG possible and successful. They are Henry Honeck who lead the effort to develop the ENDF format and the CSEWG system, Ira Zartman, the Atomic Energy Commission program manager who provided the programmatic direction and support, and Sol Pearlstein who led the development of the CESWG organization and the ENDF/B evaluated nuclear data library.

  20. Ag-Air Service

    Science.gov (United States)

    1981-01-01

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

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

    Science.gov (United States)

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

    2016-11-01

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

  2. AGS experiments: 1984, 1985, 1986. Third edition

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1986-02-01

    Brief summaries are given of 44 different experiments either running or scheduled to run at the Brookhaven National Laboratory Alternating Gradient Synchrotron, as well as the experiment schedules. The beam parameters and fluxes are tabulated. Illustrations are given of both the experimental area layouts and the apparatus for each experiment. (LEW)

  3. Multiple species beam production on laser ion source for electron beam ion source in Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Sekine, M., E-mail: sekine.m.ae@m.titech.ac.jp [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Meguro, Tokyo (Japan); Riken, Wako, Saitama (Japan); Ikeda, S. [Riken, Wako, Saitama (Japan); Department of Energy Science, Tokyo Institute of Technology, Yokohama, Kanagawa (Japan); Hayashizaki, N. [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Meguro, Tokyo (Japan); Kanesue, T.; Okamura, M. [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2014-02-15

    Extracted ion beams from the test laser ion source (LIS) were transported through a test beam transport line which is almost identical to the actual primary beam transport in the current electron beam ion source apparatus. The tested species were C, Al, Si, Cr, Fe, Cu, Ag, Ta, and Au. The all measured beam currents fulfilled the requirements. However, in the case of light mass ions, the recorded emittance shapes have larger aberrations and the RMS values are higher than 0.06 π mm mrad, which is the design goal. Since we have margin to enhance the beam current, if we then allow some beam losses at the injection point, the number of the single charged ions within the acceptance can be supplied. For heaver ions like Ag, Ta, and Au, the LIS showed very good performance.

  4. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

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

  5. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

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

  6. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

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

  7. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

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

  8. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

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

  9. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

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

  10. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

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

  11. AGS Experiments: 1989, 1990, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1992-02-01

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

  12. AGS Experiments: 1989, 1990, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1992-02-01

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

  13. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

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

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

    Science.gov (United States)

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

    2017-02-01

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

  15. Energy-related perturbations of the northeast coastal zone: five years (1974-1979) of oceanographic research at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, J.J.

    1980-03-01

    Since inception of oceanographic research at Brookhaven National Laboratory in 1974, over 75 cruises and 150 papers and reports have been completed. In comparison of shelf ecosystems at high, mid, and low latitudes, an understanding of the natural variability of US coastal waters has been derived. Annual carbon and nitrogen budgets suggest that the energy flow is diverted to a pelagic food web in summer-fall and a demersal food web in winter-spring within the Mid-Atlantic Bight. The impact of energy-related perturbations can now be assessed within the context of natural oscillation of the coastal food web.

  16. Application of the SmartSampling Methodology to the Evaluation of Contaminated Landscape Soils at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    RAUTMAN,CHRISTOPHER A.

    2000-08-01

    Portions of the SmartSampling{trademark} analysis methodology have been applied to the evaluation of radioactive contaminated landscape soils at Brookhaven National Laboratory. Specifically, the spatial, volumetric distribution of cesium-137 ({sup 137}Cs) contamination within Area of Concern 16E-1 has been modeled probabilistically using a geostatistical methodology, with the purpose of identifying the likelihood of successfully reducing, with respect to a pre-existing, baseline remediation plan, the volume of soil that must be disposed of offsite during clean-up. The principal objective of the analysis was to evaluate the likelihood of successful deployment of the Segmented Gate System (SGS), a novel remediation approach that emphasizes real-time separation of clean from contaminated materials during remediation operations. One primary requirement for successful application of the segmented gate technology investigated is that a variety of contaminant levels exist at the deployment site, which would enable to the SGS to discriminate material above and below a specified remediation threshold value. The results of this analysis indicate that there is potential for significant volume reduction with respect to the baseline remediation plan at a threshold excavation level of 23 pCi/g {sup 137}Cs. A reduction of approximately 50%, from a baseline volume of approximately 1,064.7 yd{sup 3} to less than 550 yd{sup 3}, is possible with acceptance of only a very small level of engineering risk. The vast majority of this volume reduction is obtained by not excavating almost all of levels 3 and 4 (from 12 to 24 inches in depth), which appear to be virtually uncontaminated, based on the available data. Additional volume reductions related to soil materials on levels 1 (depths of 0--6 inches) and 2 (6--12 inches) may be possible, specifically through use of the SGS technology. Level-by-level evaluation of simulation results suggests that as much as 26 percent of level 1 and as

  17. Proceedings of RIKEN BNL Research Center Workshop: Brookhaven Summer Program on Quarkonium Production in Elementary and Heavy Ion Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Dumitru, A.; Lourenco, C.; Petreczky, P.; Qiu, J., Ruan, L.

    2011-08-03

    Understanding the structure of the hadron is of fundamental importance in subatomic physics. Production of heavy quarkonia is arguably one of the most fascinating subjects in strong interaction physics. It offers unique perspectives into the formation of QCD bound states. Heavy quarkonia are among the most studied particles both theoretically and experimentally. They have been, and continue to be, the focus of measurements in all high energy colliders around the world. Because of their distinct multiple mass scales, heavy quarkonia were suggested as a probe of the hot quark-gluon matter produced in heavy-ion collisions; and their production has been one of the main subjects of the experimental heavy-ion programs at the SPS and RHIC. However, since the discovery of J/psi at Brookhaven National Laboratory and SLAC National Accelerator Laboratory over 36 years ago, theorists still have not been able to fully understand the production mechanism of heavy quarkonia, although major progresses have been made in recent years. With this in mind, a two-week program on quarkonium production was organized at BNL on June 6-17, 2011. Many new experimental data from LHC and from RHIC were presented during the program, including results from the LHC heavy ion run. To analyze and correctly interpret these measurements, and in order to quantify properties of the hot matter produced in heavy-ion collisions, it is necessary to improve our theoretical understanding of quarkonium production. Therefore, a wide range of theoretical aspects on the production mechanism in the vacuum as well as in cold nuclear and hot quark-gluon medium were discussed during the program from the controlled calculations in QCD and its effective theories such as NRQCD to various models, and to the first principle lattice calculation. The scientific program was divided into three major scientific parts: basic production mechanism for heavy quarkonium in vacuum or in high energy elementary collisions; the

  18. Self-Assembly by Instruction: Designing Nanoscale Systems Using DNA-Based Approaches (474th Brookhaven Lecture)

    Energy Technology Data Exchange (ETDEWEB)

    Gang, Oleg [Center for Functional Nanomaterials

    2012-01-18

    In the field of nanoscience, if you can control how nanoparticles self-assemble in particular structures — joining each other, for example, as molecules can form, atom-by-atom — you can design new materials that have unique properties that industry needs. Nature already uses the DNA genetic code to instruct the building of specific proteins and whole organisms in both plants and people. Taking a cue from nature, scientists at BNL devised a way of using strands of synthetic DNA attached to the surface of nanoparticles to instruct them to self-assemble into specific nanoscale structures, clusters, and three-dimensional organizations. Novel materials designed and fabricated this way promise use in photovoltaics, energy storage, catalysis, cell-targeted systems for more effective medical treatments, and biomolecular sensing for environmental monitoring and medical applications. To find out more about the rapid evolution of this nanoassembly method and its applications, join Physicist Oleg Gang of the Center for Functional Nanomaterials (CFN) as he gives the 474th Brookhaven Lecture, titled “Self-Assembly by Instruction: Designing Nanoscale Systems Using DNA-Based Approaches." Gang, who has led this work at the CFN, will explain the rapid evolution of this nanoassembly method, and discuss its present and future applications in highly specific biosensors, optically active nano-materials, and new ways to fabricate complex architectures in a rational manner via self-assembly. Gang and his colleagues used the CFN and the National Synchrotron Light Source (NSLS) facilities to perform their groundbreaking research. At the CFN, the scientists used electron microscopes and optical methods to visualize the clusters that they fabricated. At the NSLS, they applied x-rays to study a particles-assembly process in solution, DNA’s natural environment. Gang earned a Ph.D. in soft matter physics from Bar-Ilan University in 2000, and he was a Rothschild Fellow at Harvard

  19. Brookhaven National Laboratory

    Science.gov (United States)

    ... Superconducting Magnet RIKEN BNL Research Center Computational Sciences Computer Science and Mathematics BNL Scientific Data and Computing Center ... 631) 344-8000 Contact us Our Science About History Leadership Visiting the Lab Site Index Staff Directory ...

  20. Brookhaven highlights 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    Established in 1947 on Long Island, New York, on the site of the former army Camp Upton, BNL is a multidisciplinary laboratory that carries out basic and applied research in the physical, biomedical and environmental sciences and in selected energy technologies. The Laboratory is managed by Associated Universities, Inc., under contract to the US Department of Energy. BNL`s annual budget is about $400 million, and the Laboratory`s facilities are valued at replacements cost in excess of over $2.8 billion. Employees number around 3,300,and over 4,000 guests, collaborators and students come each year to use the Laboratory`s facilities and work with the staff. Scientific and technical achievements at BNL have made their way into daily life in areas as varied as health care, construction materials and video games. The backbone of these developments is fundamental research, which is and always will be an investment in the future.

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

    Science.gov (United States)

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

    2010-12-22

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

  2. Bioceres: AG Biotechnology from Argentina

    Directory of Open Access Journals (Sweden)

    Roberto Feeney

    2016-04-01

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

  3. Spectroscopy of {sup 96}Ag.

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  4. Incorporated Organic Modified Ag Nanoparticles in Ormocer

    Institute of Scientific and Technical Information of China (English)

    Haiping XIA; Jianli ZHANG; Jinhao WANG; Qiuhua NIE

    2004-01-01

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

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

    Lifescience Database Archive (English)

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

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

    Lifescience Database Archive (English)

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

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

    Lifescience Database Archive (English)

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

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

    Lifescience Database Archive (English)

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

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

    Lifescience Database Archive (English)

    Full Text Available His.Dig.05.AllAg.AGS hg19 Histone Digestive tract AGS SRX482980,SRX482979,SRX482981...,SRX482978,SRX482984,SRX482982,SRX482985,SRX482983 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Dig.05.AllAg.AGS.bed ...

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

    Lifescience Database Archive (English)

    Full Text Available ALL.Dig.10.AllAg.AGS hg19 All antigens Digestive tract AGS SRX367641,SRX367642,SRX3...X482983 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Dig.10.AllAg.AGS.bed ...

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

    Lifescience Database Archive (English)

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

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

    Lifescience Database Archive (English)

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

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

    Lifescience Database Archive (English)

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

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

    Lifescience Database Archive (English)

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

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

    Lifescience Database Archive (English)

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

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

    Lifescience Database Archive (English)

    Full Text Available His.Dig.10.AllAg.AGS hg19 Histone Digestive tract AGS SRX482979,SRX482980,SRX482981...,SRX482984,SRX482978,SRX482982,SRX482985,SRX482983 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Dig.10.AllAg.AGS.bed ...

  17. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

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

  18. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

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

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

    Science.gov (United States)

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

    2016-09-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

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

  1. Functional Ag porous films prepared by electrospinning

    Science.gov (United States)

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

    2009-06-01

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

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

    Science.gov (United States)

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

    2015-12-01

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

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

    KAUST Repository

    Pang, Maolin

    2010-08-11

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-02-15

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

  5. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

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

  6. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

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

  7. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-04-15

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

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

    Science.gov (United States)

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

    2017-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1993-04-01

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

  11. AGS experiments, 1988, 1989, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1991-04-01

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

  12. AGS experiments: 1985, 1986, 1987

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1987-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

  14. Direct electrospinning of Ag/polyvinylpyrrolidone nanocables

    DEFF Research Database (Denmark)

    Chen, Menglin; Havelund, Rasmus; Li, Qiang

    2011-01-01

    Core-sheath silver nanowire/polyvinylpyrrolidone (AgNW/PVP) nanocables have been fabricated via an efficient single-spinneret electrospinning method. The core-sheath structure is revealed by combining several characterization methods. A possible formation mechanism of the AgNW/PVP nanocable...... involving a strong stretching during the electrospinning process is proposed. Further, electrical measurements were performed on AgNW/PVP nanocables as well as bare AgNWs, which indicated the nanocables became insulating due to the isolation of highly conductive AgNWs by insulating PVP sheath. Therefore...

  15. Realization of Ag-S codoped p-type ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tian Ning, E-mail: xtn9886@zju.edu.cn [Department of Science, Zhijiang College of Zhejiang University of Technology, Hangzhou, Zhejiang 310024 (China); Department of Physics, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Li, Xiang; Lu, Zhong [Department of Science, Zhijiang College of Zhejiang University of Technology, Hangzhou, Zhejiang 310024 (China); Chen, Yong Yue [Department of Physics, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Sui, Cheng Hua [Department of Science, Zhijiang College of Zhejiang University of Technology, Hangzhou, Zhejiang 310024 (China); Wu, Hui Zhen [Department of Physics, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang 310027 (China)

    2014-10-15

    Highlights: • Ag-S codoped p-type ZnO thin films have been fabricated. • The films exhibit low resistivity and high Hall mobility and hole concentration. • A ZnO:(Ag, S)/i-ZnO/ZnO:Al homojunction has been fabricated and shows rectifying behaviors. - Abstract: Ag-S codoped ZnO films have been grown on quartz substrates by e-beam evaporation at low temperature (100 °C). The effects of Ag{sub 2}S content on the structural and electrical properties of the films were investigated. The results showed that 2 wt% Ag{sub 2}S doped films exhibited p-type conduction, with a resistivity of 0.0347 Ω cm, a Hall mobility of 9.53 cm{sup 2} V{sup −1} s{sup −1}, and a hole concentration of 1.89 × 10{sup 19} cm{sup −3} at room temperature. The X-ray photoelectron spectroscopy measurements showed that Ag and S have been incorporated into the films. To further confirm the p-type conduction of Ag-S codoped ZnO films, a ZnO:(Ag, S)/i-ZnO/ZnO:Al homojunction was fabricated and rectifying behaviors of which was measured. High electrical performance and low growth temperature indicate that Ag{sub 2}S is a promising dopant to fabricate p-type Ag-S codoped ZnO films.

  16. Polymorphism of LiAg

    Science.gov (United States)

    Pavlyuk, V. V.; Dmytriv, G. S.; Tarasiuk, I. I.; Chumak, I. V.; Pauly, H.; Ehrenberg, H.

    2010-02-01

    A phase transition from the cubic CsCl-type structure (Pm-3m space group) into a tetragonal UPb-type structure (I4 1/amd) is observed for the LiAg binary compound at ambient conditions. The crystal structure of the tetragonal modification of the LiAg binary compound was solved by direct methods in SHELXS on the base of structure factors which were extracted from a powder diffraction pattern and refined by SHELXL and the Rietveld method ( a = 3.9605(1), c = 8.2825(2) Å, Bragg R-factor = 4.81, Rf-factor = 4.87). Elevated temperatures and/or a small Li-excess versus the equimolar composition favour the cubic structure whereas ambient and lower temperatures and/or a small Li-deficiency stabilize the tetragonal structure. This reconstructive transition is reversible but proceeds slowly.

  17. Flower-like Ag/AgCl microcrystals: Synthesis and photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Daupor, Hasan; Wongnawa, Sumpun, E-mail: sumpun.w@psu.ac.th

    2015-06-01

    Silver/silver chloride (Ag/AgCl) composites with a novel flower-like morphology were prepared via a hot precipitation assisted by the vinyl acetate monomer (VAM) route. An aqueous solution of AlCl{sub 3} was mixed with the vinyl acetate monomer and acetic acid before adding a AgNO{sub 3} solution at a temperature of 100 °C. The octapod shaped flower-like Ag/AgCl particles (or “flower-like Ag/AgCl” hereinafter) has eight petals each of which was about 7–11 μm in length. The flower-like octapods were formed by preferential overgrowth along the <111> directions of the cubic seeds. Detailed studies of the growth process at different AlCl{sub 3} concentrations revealed that the concave cube developed into a Rubik's cube where eight corners grew further into the flower-like structures. The VAM and acetic acid concentration strongly affected the growth of the Ag/AgCl to the flower-like structure and their optimum concentrations were determined. The morphologies of these particles were carefully examined by scanning electron microscopy (SEM). The crystal structures and orientation relationship were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–visible diffused reflectance spectroscopy (DRS). The flower-like Ag/AgCl microcrystals were tested for their photocatalytic degradation of orange G dye (OG) catalyzed by visible light. From comparative test runs, the flower-like Ag/AgCl exhibited better photocatalytic activity than simple and commercial Ag/AgCl particles. - Highlights: • Interesting transformation of microcrystals Ag/AgCl from concave cube via Rubik's cube to flower-like shape. • The first to use VAM as morphology control reagent. • High photocatalytic activity under visible light irradiation.

  18. Capacitive deionization of seawater effected by nano Ag and Ag@C on graphene.

    Science.gov (United States)

    Cai, P-F; Su, C-J; Chang, W-T; Chang, F-C; Peng, C-Y; Sun, I-W; Wei, Y-L; Jou, C-J; Wang, H Paul

    2014-08-30

    Drinking water shortage has become worse in recent decades. A new capacitive deionization (CDI) method for increasing water supplies through the effective desalination of seawater has been developed. Silver as nano Ag and Ag@C which was prepared by carbonization of the Ag(+)-β-cyclodextrin complex at 573 K for 30 min can add the antimicrobial function into the CDI process. The Ag@C and Ag nanoparticles dispersed on reduced graphene oxide (Ag@C/rGO and nano Ag/rGO) were used as the CDI electrodes. The nano Ag/rGO and Ag@C/rGO electrodes can reduce the charging resistant, and enhance the electrosorption capability. Better CDI efficiencies with the nano Ag/rGO and Ag@C/rGO electrodes can therefore be obtained. When reversed the voltage, the electrodes can be recovered up to 90% within 5 min. This work presents the feasibility for the nano Ag and Ag@C on rGO electrodes applied in CDI process to produce drinking water from seawater or saline water.

  19. Facile synthesis of S-Ag nanocomposites and Ag2S short nanorods by the interaction of sulfur with AgNO3 in PEG400

    Science.gov (United States)

    Zhang, Yan-Li; Xie, Xin-Yuan; Liang, Ming; Xie, Shu-Ming; Chen, Jie-Mei; Zheng, Wen-Jie

    2016-06-01

    A facile, eco-friendly and inexpensive method to prepare Ag2S short nanorods and S-Ag nanocomposites using sublimed sulfur, AgNO3, PVP and PEG400 was studied. According to x-ray diffraction and scanning electron microscopy of the Ag2S, the products are highly crystalline and pure Ag2S nanorods with diameters of 70-160 nm and lengths of 200-360 nm. X-ray diffraction of the S-Ag nanocomposites shows that we obtained cubic Ag and S nanoparticles. Transmission electron microscopy shows that the molar ratio of PVP to Ag+ plays an important role in controlling the size and morphology of the S-Ag nanocomposites. When the molar ratio of PVP to Ag+ was 10:1, smaller sizes, better dispersibility and narrower distribution of S-Ag nanocomposites with diameters of 10-40 nm were obtained. The formation mechanism of the S-Ag nanocomposites was studied by designing a series of experiments using ultraviolet-visible measurement, and it was found that S nanoparticles are produced first and act as seed crystals; then Ag+ becomes Ag nanocrystals on the surfaces of the S nanoparticles by the reduction of PVP. PEG400 acts as a catalyzer, accelerating the reaction rate, and protects the S-Ag nanocomposites from reacting to produce Ag2S. The antimicrobial experiments show that the S-Ag nanocomposites have greater antimicrobial activity on Staphylococcus aureus, Aspergillus niger and blue mold than Ag nanoparticles.

  20. A Fast, Versatile Nanoprobe for Complex Materials: The Sub-micron Resolution X-ray Spectroscopy Beamline at NSLS-II (491st Brookhaven Lecture)

    Energy Technology Data Exchange (ETDEWEB)

    Thieme, Juergen [BNL Photon Sciences Directorate

    2014-02-06

    Time is money and for scientists who need to collect data at research facilities like Brookhaven Lab’s National Synchrotron Light Source (NSLS), “beamtime” can be a precious commodity. While scanning a complex material with a specific technique and standard equipment today would take days to complete, researchers preparing to use brighter x-rays and the new sub-micron-resolution x-ray spectroscopy (SRX) beamline at the National Synchrotron Light Source II (NSLS-II) could scan the same sample in greater detail with just a few hours of beamtime. Talk about savings and new opportunities for researchers! Users will rely on these tools for locating trace elements in contaminated soils, developing processes for nanoparticles to deliver medical treatments, and much more. Dr. Thieme explains benefits for next-generation research with spectroscopy and more intense x-rays at NSLS-II. He discusses the instrumentation, features, and uses for the new SRX beamline, highlighting its speed, adjustability, and versatility for probing samples ranging in size from millimeters down to the nanoscale. He will talk about complementary beamlines being developed for additional capabilities at NSLS-II as well.

  1. The Relativistic Heavy Ion Collider (rhic) Cryogenic System at Brookhaven National Laboratory: Review of the Modifications and Upgrades Since 2002 and Planned Improvements

    Science.gov (United States)

    Than, R.; Tuozzolo, J.; Sidi-Yekhlef, A.; Ganni, V.; Knudsen, P.; Arenius, D.

    2008-03-01

    Brookhaven National Laboratory continues its multi-year program to improve the operational efficiency, reliability, and stability of the cryogenic system, which also resulted in an improved beam availability of the Relativistic Heavy Ion Collider (RHIC). This paper summarizes the work and changes made after each phase over the past four years to the present, as well as proposed future improvements. Power usage dropped from an initial 9.4 MW to the present 5.1 MW and is expected to drop below 5 MW after the completion of the remaining proposed improvements. The work proceeded in phases, balancing the Collider's schedule of operation, time required for the modifications and budget constraints. The main changes include process control, compressor oil removal and management, elimination of the use of cold compressors and two liquid-helium storage tanks, insulation of the third liquid-helium storage tank, compressor-bypass flow reduction and the addition of a load turbine (Joule-Thomson expander) with associated heat exchangers at the cold end of the plant. Also, liquid helium pumps used for forced circulation of the sub-cooled helium through the magnet loops were eliminated by an accelerator supply flow reconfiguration. Planned future upgrades include the resizing of expanders 5 and 6 to increase their efficiencies.

  2. Ag nanoprisms with Ag₂S attachment.

    KAUST Repository

    Xiong, Shenglin

    2013-01-01

    Triangular Ag nanoprisms are a type of most-studied noble-metal nanostructures over the past decade owing to their special structural architecture and outstanding optical and catalytic properties for a wide range of applications. Nevertheless, in contrast to active research for the synthesis of phase-pure Ag nanoprisms, no asymmetric heterodimers containing Ag prisms have been developed so far, probably due to lack of suitable synthetic methods. Herein, we devise a simple ion-exchange method to synthesize Ag2S/Ag heterodimers at room temperature, through which Ag nanoprisms with controllable size and thickness can be fabricated. Formation chemistry and optical properties of the heterodimers have been investigated. These semiconductor/metal heterodimers have exhibited remarkable bactericidal activity to E. coli cells under visible light illumination.

  3. A Study of Surfactant-Induced Growth of Ag on Ag (111)

    Institute of Scientific and Technical Information of China (English)

    WU Li-Li; HU Juan-Mei; WU Feng-Min

    2008-01-01

    A new growth model is introduced to describe surfactant-induced growth of Ag on Ag (111) with realistic physical parameters. In this model, the A-S exchange mechanism is considered for the first time. Using the Monte Carlo simulations, the influence of exchange mechanism, surface temperature T, the exchange barrier Eex, and the coverage of surfactant θM on the growth mode and morphology during multilayer film growth of Ag/Ag (111) are studied in detail. Both the referenced value of surfactant coverage and the method to obtain perfect layer-by-layer film in surfactant-induced Ag/Ag (111) system are provided. Our simulation results are consistent with many experimental observations for surfactant-induced growth of Ag on Ag (111).

  4. Transformation from Ag@Ag3PO4 to Ag@Ag2SO4 hybrid at room temperature: preparation and its visible light photocatalytic activity

    Science.gov (United States)

    Wei, Ting; Gao, Shanmin; Wang, Qingyao; Xu, Hui; Wang, Zeyan; Huang, Baibiao; Dai, Ying

    2017-02-01

    In the present study, Ag/Ag2SO4 hybrid photocatalysts were obtained via a facile redox-precipitation reaction approach by using Ag@Ag3PO4 nanocomposite as the precursor and KMnO4 as the oxidant. Multiple techniques, such as X-ray diffraction pattern (XRD), transmission electron microscope (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS) and Brunauer-Emmett-Teller (BET), photocurrent and electrochemical impedance spectroscopy (EIS), were applied to investigate the structures, morphologies, optical, and electronic properties of as-prepared samples. The photocatalytic activities were evaluated by photodegradation of organic rhodamine B (RhB) and methyl orange (MO) under visible light irradiation. It was found that pure Ag2SO4 can partially transform into metallic Ag during the photocatalytic degradation of organic pollutants, but the Ag/Ag2SO4 hybrids can maintain its structure stability and show enhanced visible light photocatalytic activity because of the surface plasma resonance effect of the metallic Ag.

  5. Highly efficient visible light plasmonic photocatalyst Ag@Ag(Br,I).

    Science.gov (United States)

    Wang, Peng; Huang, Baibiao; Zhang, Qianqian; Zhang, Xiaoyang; Qin, Xiaoyan; Dai, Ying; Zhan, Jie; Yu, Jiaoxian; Liu, Haixia; Lou, Zaizhu

    2010-09-03

    The new plasmonic photocatalyst Ag@Ag(Br,I) was synthesized by the ion-exchange process between the silver bromide and potassium iodide, then by reducing some Ag(+) ions in the surface region of Ag(Br,I) particles to Ag(0) species. Ag nanoparticles are formed from Ag(Br,I) by the light-induced chemical reduction reaction. The Ag@Ag(Br,I) particles have irregular shapes with their sizes varying from 83 nm to 1 mum. The as-grown plasmonic photocatalyst shows strong absorption in the visible light region because of the plasmon resonance of Ag nanoparticles. The ability of this compound to reduce Cr(VI) under visible light was compared with those of other reference photocatalyst. The plasmonic photocatalyst is shown to be highly efficient under visible light. The stability of the photocatalyst was examined by X-ray diffraction and X-ray photoelectron spectroscopy. The XRD pattern and XPS spectra prove the stability of the plasmonic photocatalyst Ag@Ag(Br,I).

  6. Visible light driven photocatalysis and antibacterial activity of AgVO{sub 3} and Ag/AgVO{sub 3} nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Anamika [Department of Life Sciences, University of Mumbai, Santacruz (E), Mumbai 400 098 (India); Dutta, Dimple P., E-mail: dimpled@barc.gov.in [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Ballal, A. [Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Tyagi, A.K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Fulekar, M.H. [School of Environment and Sustainable Development, Central University of Gujarat, Gandhinagar 382 030, Gujarat (India)

    2014-03-01

    Graphical abstract: - Highlights: • Ag/AgVO{sub 3} and pure AgVO{sub 3} nanowires synthesized by sonochemical process. • Characterization done using XRD, SEM, TEM, EDX and BET analysis. • Visible light degradation of RhB by Ag/AgVO{sub 3} within 45 min. • Antibacterial activity of Ag/AgVO{sub 3} demonstrated. - Abstract: Ag/AgVO{sub 3} nanowires and AgVO{sub 3} nanorods were synthesized in aqueous media via a facile sonochemical route. The as-synthesized products were characterized by X-ray diffraction, Brunauer–Emmett–Teller surface area analysis, scanning electron microscopy together with an energy dispersion X-ray spectrum analysis, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy. The results revealed that inert atmosphere promotes the formation of Ag/AgVO{sub 3} nanowires. The photocatalytic studies revealed that the Ag/AgVO{sub 3} nanowires exhibited complete photocatalytic degradation of Rhodamine B within 45 min under visible light irradiation. The antibacterial activity of Ag/AgVO{sub 3} nanowires was tested against Escherechia coli and Bacillus subtilis. The minimum growth inhibitory concentration value was found to be 50 and 10 folds lower than for the antibiotic ciprofloxacin for E. coli and B. subtilis, respectively. The antibacterial properties of the β-AgVO{sub 3} nanorods prove that in case of the Ag dispersed Ag/AgVO{sub 3} nanowires, the enhanced antibacterial action is also due to contribution from the AgVO{sub 3} support.

  7. Effects of soil and dietary exposures to Ag nanoparticles and AgNO₃ in the terrestrial isopod Porcellionides pruinosus.

    Science.gov (United States)

    Tourinho, Paula S; van Gestel, Cornelis A M; Jurkschat, Kerstin; Soares, Amadeu M V M; Loureiro, Susana

    2015-10-01

    The effects of Ag-NPs and AgNO3 on the isopod Porcellionides pruinosus were determined upon soil and dietary exposures. Isopods avoided Ag in soil, with EC50 values of ∼16.0 and 14.0 mg Ag/kg for Ag-NPs and AgNO3, respectively. Feeding inhibition tests in soil showed EC50s for effects on consumption ratio of 127 and 56.7 mg Ag/kg, respectively. Although similar EC50s for effects on biomass were observed for nanoparticulate and ionic Ag (114 and 120 mg Ag/kg dry soil, respectively), at higher concentrations greater biomass loss was found for AgNO3. Upon dietary exposure, AgNO3 was more toxic, with EC50 for effects on biomass change being >1500 and 233 mg Ag/kg for Ag-NPs and AgNO3, respectively. The difference in toxicity between Ag-NPs and AgNO3 could not be explained from Ag body concentrations. This suggests that the relation between toxicity and bioavailability of Ag-NPs differs from that of ionic Ag in soils.

  8. Kinetics of Ag-rich precipitates formation in Cu-Al-Ag alloys

    Energy Technology Data Exchange (ETDEWEB)

    Adorno, A.T.; Guerreiro, M.R.; Silva, R.A.G

    2004-06-15

    The kinetics of Ag-rich precipitates formation in the Cu-2 wt.% Al alloy with additions of 2, 4, 6, 8, 10 and 12 wt.% Ag was studied using microhardness changes with temperature and time, differential scanning calorimetry (DSC), differential thermal analysis (DTA), scanning electron microscopy (SEM), optical microscopy (OM), energy dispersive X-ray analysis (EDX) and X-ray diffractometry (XRD). The results indicated that an increase in the Ag content decreases the activation energy for Ag-rich precipitates formation, and that it is possible to estimate the values of the diffusion and nucleation activation energies for the Ag precipitates.

  9. Photocatalytic oxidation removal of Hg0 using ternary Ag/AgI-Ag2CO3 hybrids in wet scrubbing process under fluorescent light

    Science.gov (United States)

    Zhang, Anchao; Zhang, Lixiang; Chen, Xiaozhuan; Zhu, Qifeng; Liu, Zhichao; Xiang, Jun

    2017-01-01

    A series of ternary Ag/AgI-Ag2CO3 photocatalysts synthesized using a facile coprecipitation method were employed to investigate their performances of Hg0 removal in a wet scrubbing reactor. The hybrids were characterized by N2 adsorption-desorption, XRD, SEM-EDS, HRTEM, XPS, DRS and ESR. The photocatalytic activities of Hg0 removal were evaluated under fluorescent light. The results showed that AgI content, fluorescent light irradiation, reaction temperature all showed significant influences on Hg0 removal. NO exhibited significant effect on Hg0 removal in comparison to SO2. Among these ternary Ag/AgI-Ag2CO3 hybrids, Ag/AgI(0.1)-Ag2CO3 showed the highest Hg0 removal efficiency, which could be ascribed to the effective separation of photogenerated electron-hole pairs between AgI and Ag2CO3 and the surface plasmon resonance (SPR) effect in the visible region by metallic silver nanoparticles (Ag0 NPs). The trapping studies of reactive radicals showed that the superoxide radicals (rad O2-) may play a key role in Hg0 removal under fluorescent light. According to the experimental and characterization results, a possible photocatalytic oxidation mechanism for enhanced Hg0 removal over Ag/AgI(0.1)-Ag2CO3 hybrid under fluorescent light was proposed.

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

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The experimental investigations on the interaction between Ag-nanocrystal particles (Ag-NCPs) and carbon nanotubes (CNTs) in Ag-nanocrystal particles/carbon nanotubes (Ag-NCPs/CNTs) hybrid structures were reported. The growth of Ag-NCPs on multiwalled carbon nanotubes (MWCNTs) was carried out by thermal evaporation deposition. High-resolution transmission electron microscopy and X-ray diffraction analyses revealed that Ag-NCPs had the crystal lattice feature of face-centered cube (fcc). The growth of Ag-NCPs on MWCNTs induced the cross-section deformation of MWCNT. The experimental results also showed that the synthesized Ag-NCPs/CNTs hybrid structure appeared as quasi-one dimensional nanowires containing the Ag-NCP/CNT hetero-junction. There was local cross-section deformation on MWCNTs at the interface of hetero-junction. These results involve the important topic about fundamental and practical studies for structure of MNCPs on CNTs and also find clues to further research of Ag nanocrystal growing on MWCNTs and related Ag-CNT interaction.

  11. 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.

  12. Label-Free Detection of Ag+ Based on Gold Nanoparticles and Ag+-Specific DNA.

    Science.gov (United States)

    Pu, Wendan; Zhao, Zhao; Wu, Liping; Liu, Yue; Zhao, Huawen

    2015-08-01

    A sensitive label-free method was presented for the determination of silver ion (Ag+) in this paper. Cytosine-rich DNA (C-DNA) was used as Ag+ specific DNA. Without Ag+ in the solution, fluorescence of fluorescein (FAM) is quenched by C-DNA stabilized gold nanoparticles (AuNPs) in high salt environment. When Ag+ is present in the solution, however, Ag+-mediated cytosine-Ag+-cytosine (C-Ag+-C) base pairs induced the C-DNA folding into a hairpin structure, which can not stabilize AuNPs in high salt environment, thus causing AuNPs aggregation. After centrifugation to remove the aggregated AuNPs, the quenching ability of the supernatant for FAM is decreased and the fluorescence intensity of solution increases with increasing the Ag+ concentration. Due to the highly specific interaction of the C-DNA towards Ag+ and the strong fluorescent quenching ability of AuNPs for FAM, the method has high selectivity and sensitivity for Ag+. Under the optimal conditions, the fluorescence intensity at 515 nm increased linearly with the concentration of Ag+ ranging from 15 nM to 700 nM, and the detection limit was determined as 6 nM based on 3 σ/slope. This method is simple, sensitive, and may be applied to other detection systems by selecting the appropriate DNA sequences.

  13. 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.

  14. 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.

  15. Identification of Ag-acceptor related photoluminescence in $^{111}\\!$Ag doped CdTe

    CERN Document Server

    Hamann, J; Deicher, M; Filz, T; Ostheimer, V; Schmitz, C; Wolf, H; Wichert, T

    1998-01-01

    Bridgman-grown, nominally undoped CdTe crystals were doped with Ag by implanting radioactive $^{111}\\!$Ag. Photoluminescence spectra of the crystals show a donor-acceptor pair (DAP) line at 1.491 eV. The decrease of the intensity of this line with a half life of T$_{1/2}$=(7.2$\\pm$0.4) d is in good agreement with the half life of the $\\beta\\!^{-}$-decay of $^{111}\\!$Ag to $^{111}\\!$Cd of 7.45 d. This decrease is not caused by the aging behavior of Ag which was reported in the literature. The data show that the involved acceptor defect contains exactly one Ag atom and confirm the earlier assignment of the acceptor to the AgCd defect. Based on the DAP line at 1.491 eV, the spectra did not reveal a contamination of the CdTe crystals by stable Ag.

  16. Ligand and counterion control of Ag(I) architectures: assembly of a {Ag8} ring cluster mediated by hydrophobic and Ag...Ag interactions.

    Science.gov (United States)

    Fielden, John; Long, De-liang; Slawin, Alexandra M Z; Kögerler, Paul; Cronin, Leroy

    2007-10-29

    A strategy combining ligand design and counterion variation has been used to investigate the assembly of silver(I) complexes. As a result, dinuclear, octanuclear, and polymeric silver(I) species have been synthesized by complexation of the rigid aliphatic amino ligands cis-3,5-diamino-trans-hydroxycyclohexane (DAHC), cis-3,5-diamino-trans-methoxycyclohexane (DAMC), and cis-3,5-diamino-trans-tert-butyldimethylsilylanyloxycyclohexane (DATC) with silver(I) triflate, nitrate, and perchlorate. The compositions of these aggregates, established by X-ray crystallography and elemental analysis, are [{Ag(DAHC)}2](CF3SO3)2 (1), [{Ag(DAMC)}2](CF3SO3)2 (2), [{Ag(DAMC)}2](NO3)2 (3), [{Ag(DATC)}6{Ag(DAHC)}2](NO3)8 (4), and [{Ag(DATC}n](NO3)n (5), where the DAHC present in 4 is formed by in situ hydrolysis of the acid labile silyl ether group. The type of aggregate formed depends both upon the noncoordinating O-substituent of the ligand and the (also noncoordinating) counterion, with the normal preference of the ligand topology for forming Ag2L2 structures being broken by introduction of the bulky, lipophilic O-tert-butyldimethylsilyl (TBDMS) group. Of particular note is the octanuclear silver ring structure 4, which is isolated only when both the O-TBDMS group and the nitrate counteranion are present and is formed from four Ag2L2 dimers connected by Ag...Ag and hydrogen-bonding interactions. Diffusion rate measurement of this {Ag8} complex by 1H NMR (DOSY) indicates dissociation in CD3OD and CD3CN, showing that this supramolecular ring structure is formed upon crystallization, and establishing a qualitative limit to the strength of Ag...Ag interactions in solution. When solutions of the {Ag8} cluster in methanol are kept for several days though, a new UV-vis absorption is observed at around 430 nm, consistent with the formation of silver nanoparticles.

  17. Preparation and Characterization of γ-AgI in Superionic Composite Glasses (AgIx(AgPO31-x

    Directory of Open Access Journals (Sweden)

    S. Suminta

    2007-07-01

    Full Text Available The γ-AgI phase was stabilized at room temperature in the composites glasses (AgIx(AgPO31-x with x = 0.6 and 0.7 via rapid quenching of their molten mixture. The measurement of the crystal structure has been carried out using an X-ray Difractometer at the Physics Departement of Ibaraki University, Japan. The micro strain and crystal size are derived from Hall’s equation. The X-ray diffraction pattern shows some Bragg peaks that correspond to the crystalline γ-AgI. By increasing the concentration of AgI, the peak width becomes more narrow and the position shifts to the higher angle. This indicates that the crystalline size and microstrain are increasing. The increase of micro strain (η, and particle size (D will increase the ionic mobility, thus increasing the ionic conductivity. It is concluded that solidification process on melt AgI into glass matrix AgPO3 not only decreases the micro strain and the particle size, but it also increases the ionic conductivity.

  18. Spectroscopic Study on Eu3+ Doped Borate Glasses Containing Ag Nanoparticles and Ag Aggregates.

    Science.gov (United States)

    Fu, Shaobo; Zheng, Hui; Zhang, Jinsu; Li, Xiangping; Sun, Jiashi; Hua, Ruinian; Dong, Bin; Xia, Haiping; Chen, Baojiu

    2015-01-01

    Transparent Eu(3+)-doped borate glasses containing Ag nanoparticles and Ag aggregates with composition (40 - x) CaO-59.5B2O3-0.5Eu2O3-xAgNO3 were prepared by a simple one-step melt-quenching technique. The X-ray diffraction (XRD) patterns of the glasses reveal amorphous structural properties and no diffraction peaks belonging to metal Ag particles. Ag particles and Ag aggregates were observed from the absorption spectra. Effective energy transfers from the Ag aggregates to the Eu3+ ions were observed in the excitation spectra from monitoring the intrinsic emission of Eu3+x .5D0 --> 7F2. The glasses with higher Ag content can be effectively excited by light in a wide wavelength region, indicating that these glasses have potential application in the solid state lighting driven by semiconductor light emitting diodes (LEDs). The emission spectra of the samples with higher Ag contents exhibit plenteous spectral components covering the full visible region from violet to red, thus indicating that these glass materials possess an excellent and tunable color rendering index. The color coordinates for all the glass samples were calculated by using the intensity-corrected emission spectra and the standard data issued by the CIE (Commission International de l' Eclairage) in 1931. It was found that the color coordinates for most samples with higher Ag contents fall into the white region in the color space.

  19. Study of antibacterial activity of Ag and Ag2CO3 nanoparticles stabilized over montmorillonite.

    Science.gov (United States)

    Sohrabnezhad, Sh; Pourahmad, A; Mehdipour Moghaddam, M J; Sadeghi, A

    2015-02-05

    Silver carbonate and silver nanoparticles (NPs) over of stabilizer montmorillonite (MMT) have been synthesized in aqueous and polyol solvent, respectively. Dispersions of silver nanoparticles have been prepared by the reduction of silver nitrate over of MMT in presence and absence of Na2CO3 compound in ethylene glycol. It was observed that montmorillonite was capable of stabilizing formed Ag nanoparticles through the reduction of Ag(+) ions in ethylene glycol. Na2CO3 was used as carbonate source in synthesis of Ag2CO3 NPs in water solvent and also for controlling of Ag nanoparticles size in ethylene glycol medium. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and ultraviolet-visible diffuse reflectance spectroscopy (DRS). The TEM images showed that Ag NPs size in presence Na2CO3 salts was smaller than without that. The results indicated intercalation of Ag and Ag2CO3 nanoparticles into the montmorillonite clay layers. The diffuse reflectance spectra exhibited a strong surface plasmon resonance (SPR) adsorption peak in the visible region, resulting from Ag nanoparticles. The antibacterial testing results showed that the Ag2CO3-MMT nanocomposite exhibited an antibacterial activity higher than Ag-MMT sample against Escherichia coli.

  20. Ag nanoparticle/polymer composite barcode nanorods

    Institute of Scientific and Technical Information of China (English)

    Hongxu Chen[1; Tieqiang Wang[2; Huaizhong Shen[1; Wendong Liu[1; Shuli Wang[1; Kun Liu[1; Junhu Zhang[1; Bai Yang[1

    2015-01-01

    We demonstrate a facile method combining colloidal lithography, selective ion-exchange, and the in situ reduction of Ag ions (Ag+) for the fabrication of multi-segmented barcode nanorods. First, polymer multilayer films were prepared by spin-coating alternating thin films of polystyrene and polyacrylic acid (PAA), and then multi-segmented polymer nanorods were fabricated via reactive ion etching with colloidal masks. Second, Ag nanoparticles (Ag NPs) were incorporated into the PAA segments by an ion exchange and the in situ reduction of the Ag~. The selective incorporation of the Ag NPs permitted the modification of the specific bars of the nanorods. Lastly, the Ag NP/polymer composite nanorods were released from the substrate to form suspensions for further coding applications. By increasing the number of segments and changing the length of each segment in the nanorods, the coding capacity of nanorods was improved. More importantly, this method can easily realize the density tuning of Ag NPs in different segments of a single nanorod by varying the composition of the PAA segments. We believe that numerous other coded materials can also be obtained, which introduces new approaches for fabricating barcoded nanomaterials.

  1. A FLYING WIRE SYSTEM IN THE AGS.

    Energy Technology Data Exchange (ETDEWEB)

    HUANG,H.; BUXTON,W.; MAHLER,G.; MARUSIC,A.; ROSER,T.; SMITH,G.; SYPHERS,M.; WILLIAMS,N.; WITKOVER,R.

    1999-03-29

    As the AGS prepares to serve as the injector for RHIC, monitoring and control of the beam transverse emittance become a major and important topic. Before the installation of the flying wire system, the emittance was measured with ionization profile monitors in the AGS, which require correction for space charge effects. It is desirable to have a second means of measuring profile that is less depend on intensity. A flying wire system has been installed in the AGS recently to perform this task. This paper discusses the hardware and software setup and the capabilities of the system.

  2. Optical properties of AgI/Ag infrared hollow fiber in the visible wavelength region.

    Science.gov (United States)

    Sui, Ke-Rong; Shi, Yi-Wei; Tang, Xiao-Li; Zhu, Xiao-Song; Iwai, Katsumasa; Miyagi, Mitsunobu

    2008-02-15

    We report on AgI/Ag infrared hollow fiber with low-loss in visible region. Improved methods of silver plating and iodination were proposed to fabricate the hollow fiber. The surface roughness of the silver layer and the silver iodide layer was reduced by the pretreatment with an SnCl2 solution and low iodination temperature. Losses for the Er:YAG and green laser light were 0.4 and 7dB/m. The loss property of green laser beam was low to deliver a pilot beam for the invisible infrared laser light. Owing to the smooth and uniform AgI film, the loss spectrum of the hollow fiber showed clear interference peaks in the visible region. An empirical formula for AgI material dispersion was derived, which is of special importance for the design of high-performance AgI/Ag hollow fiber.

  3. Theoretical Investigation on the Adsorption of Ag+ and Hydrated Ag+ Cations on Clean Si(111)Surface

    Institute of Scientific and Technical Information of China (English)

    SHENG Yong-Li; LI Meng-Hua; WANG Zhi-Guo; LIU Yong-Jun

    2008-01-01

    In this paper,the adsorption of Ag+ and hydrated Ag+ cations on clean Si(111)surface were investigated by using cluster(Gaussian 03)and periodic(DMol3)ab initio calculations.Si(111)surface was described with cluster models(Si14H17 and Si22H21)and a four-silicon layer slab with periodic boundary conditions.The effect of basis set superposition error(BSSE)was taken into account by applying the counterpoise correction.The calculated results indicated that the binding energies between hydrated Ag+ cations and clean Si(111)surface are large,suggesting a strong interaction between hydrated Ag+ cations and the semiconductor surface.With the increase of number,water molecules form hydrogen bond network with one another and only one water molecule binds directly to the Ag+ cation.The Ag+ cation in aqueous solution will safely attach to the clean Si(111)surface.

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

    Energy Technology Data Exchange (ETDEWEB)

    Silva, R.A.G., E-mail: galdino.ricardo@gmail.com [Departamento de Ciências Exatas e da Terra, UNIFESP, 09972-270 Diadema, SP (Brazil); Paganotti, A.; Jabase, L. [Departamento de Ciências Exatas e da Terra, UNIFESP, 09972-270 Diadema, SP (Brazil); Adorno, A.T.; Carvalho, T.M.; Santos, C.M.A. [Departamento de Físico-Química, Instituto de Química, UNESP, 14801-970 Araraquara, SP (Brazil)

    2014-12-05

    Highlights: • Cu-rich nanoprecipitates are formed in the presence of Ag. • Bainite precipitation is shifted to higher temperatures in the Cu–11%Al–10%Mn–3%Ag alloy. • The eutectoid α phase and bainite α{sub 1} phase compete by the Cu atoms during precipitation process. - Abstract: The formation of Ag-rich precipitates in the Cu–11%Al–10%Mn–3%Ag alloy initially quenched from 1123 K was analyzed. The results showed that nanoprecipitates of a Cu-rich phase are produced at about 523 K. In higher temperatures these nanoparticles grow and the relative fraction of Ag dissolved in it is increased, thus forming the Ag-rich phase.

  5. Comparative toxicity study of Ag, Au, and Ag-Au bimetallic nanoparticles on Daphnia magna.

    Science.gov (United States)

    Li, Ting; Albee, Brian; Alemayehu, Matti; Diaz, Rocio; Ingham, Leigha; Kamal, Shawn; Rodriguez, Maritza; Bishnoi, Sandra Whaley

    2010-09-01

    A comparative assessment of the 48-h acute toxicity of aqueous nanoparticles synthesized using the same methodology, including Au, Ag, and Ag-Au bimetallic nanoparticles, was conducted to determine their ecological effect in freshwater environments through the use of Daphnia magna, using their mortality as a toxicological endpoint. D. magna are one of the standard organisms used for ecotoxicity studies due to their sensitivity to chemical toxicants. Particle suspensions used in toxicity testing were well-characterized through a combination of absorbance measurements, atomic force or electron microscopy, flame atomic absorption spectrometry, and dynamic light scattering to determine composition, aggregation state, and particle size. The toxicity of all nanoparticles tested was found to be dose and composition dependent. The concentration of Au nanoparticles that killed 50% of the test organisms (LC(50)) ranged from 65-75 mg/L. In addition, three different sized Ag nanoparticles (diameters = 36, 52, and 66 nm) were studied to analyze the toxicological effects of particle size on D. magna; however, it was found that toxicity was not a function of size and ranged from 3-4 μg/L for all three sets of Ag nanoparticles tested. This was possibly due to the large degree of aggregation when these nanoparticles were suspended in standard synthetic freshwater. Moreover, the LC(50) values for Ag-Au bimetallic nanoparticles were found to be between that of Ag and Au but much closer to that of Ag. The bimetallic particles containing 80% Ag and 20% Au were found to have a significantly lower toxicity to Daphnia (LC(50) of 15 μg/L) compared to Ag nanoparticles, while the toxicity of the nanoparticles containing 20% Ag and 80% Au was greater than expected at 12 μg/L. The comparison results confirm that Ag nanoparticles were much more toxic than Au nanoparticles, and that the introduction of gold into silver nanoparticles may lower their environmental impact by lowering the amount

  6. Epigallocatechin-3-gallate-capped Ag nanoparticles: preparation and characterization.

    Science.gov (United States)

    Hussain, Shokit; Khan, Zaheer

    2014-07-01

    We used an aqueous leaf extract of Camellia sinensis to synthesize Ag nanoparticles (AgNPs). A layer of ca. 6 nm around a group of the AgNPs in which the inner layer is bound to the AgNPs surface via the hydroxyl groups of catechin has been observed. TEM analysis of AgNPs showed the formation of truncated triangular nanoplates and/or nanodisks and spherical with some irregular-shaped polydispersed nanoparticles in absence and presence of shape-directing cetyltrimethylammonium bromide. The polyphenolic groups of epigallocatechin-3-gallate (EGCG) are responsible for the rapid reduction of Ag(+) ions into metallic Ag(0). The free -OH groups are able to stabilize AgNPs by the interaction between the surface Ag atoms of AgNPs and oxygen atoms of EGCG molecules.

  7. AgSat Imagery Collection Footprints

    Data.gov (United States)

    Farm Service Agency, Department of Agriculture — The AgSat Imagery Collection Footprints map shows the imagery footprints which have been collected under the USDA satellite blanket purchase agreement. Click on a...

  8. AgSat Areas of Interest

    Data.gov (United States)

    Farm Service Agency, Department of Agriculture — The AgSat Areas of Interest map contains area polygons where satellite imagery will be collected for the Farm Service Agency (FSA) to provide imagery coverage for...

  9. Redetermination of AgPO(3).

    Science.gov (United States)

    Terebilenko, Katherina V; Zatovsky, Igor V; Ogorodnyk, Ivan V; Baumer, Vyacheslav N; Slobodyanik, Nikolay S

    2011-02-09

    Single crystals of silver(I) polyphosphate(V), AgPO(3), were prepared via a phospho-ric acid melt method using a solution of Ag(3)PO(4) in H(3)PO(4). In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779-784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO(5)] polyhedra, giving rise to multidirectional ribbons, and from two types of PO(4) tetra-hedra linked into meandering chains (PO(3))(n) spreading parallel to the b axis with a repeat unit of four tetra-hedra. The calculated bond-valence sum value of one of the two Ag(I) ions indicates a significant strain of the structure.

  10. Redetermination of AgPO3

    Science.gov (United States)

    Terebilenko, Katherina V.; Zatovsky, Igor V.; Ogorodnyk, Ivan V.; Baumer, Vyacheslav N.; Slobodyanik, Nikolay S.

    2011-01-01

    Single crystals of silver(I) polyphosphate(V), AgPO3, were prepared via a phospho­ric acid melt method using a solution of Ag3PO4 in H3PO4. In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779–784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO5] polyhedra, giving rise to multidirectional ribbons, and from two types of PO4 tetra­hedra linked into meandering chains (PO3)n spreading parallel to the b axis with a repeat unit of four tetra­hedra. The calculated bond-valence sum value of one of the two AgI ions indicates a significant strain of the structure. PMID:21522230

  11. Temperature stability of AgCu nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Sopoušek, Jiří, E-mail: sopousek@mail.muni.cz; Zobač, Ondřej; Vykoukal, Vít [Masaryk University, Department of Chemistry, Faculty of Science (Czech Republic); Buršík, Jiří; Roupcová, Pavla [Institute of Physics of Materials ASCR (Czech Republic); Brož, Pavel; Pinkas, Jiří [Masaryk University, Department of Chemistry, Faculty of Science (Czech Republic); Vřešťál, Jan [Masaryk University, Central European Institute of Technology, CEITEC (Czech Republic)

    2015-12-15

    The colloidal solutions of the Ag–Cu nanoparticles (NPs, 10–32 nm) were prepared by solvothermal reactions. The samples of dried AgCu NPs and the resulting microstructures after heat treatment in air were investigated by various methods including electron microscopy (TEM, SEM) and high-temperature X-ray powder diffraction (HTXRD). The AgCu randomly mixed, Cu-rich, and Ag-rich face centred cubic crystal lattices were detected during the experiments. The temperature induced sintering was observed experimentally by HTXRD at 250 °C. The phase transformations at high temperatures were monitored by differential scanning calorimetry. The formation of the Ag-rich grains during heating in air and evolution of copper oxide microstructure were detected.Graphical abstract.

  12. Brookhaven superconducting cable test facility

    Energy Technology Data Exchange (ETDEWEB)

    Forsyth, E.B.; Gibbs, R.J.

    1976-08-17

    Construction has started on an outdoor testing station for flexible ac superconducting power transmission cables. It is intended to serve as an intermediate step between laboratory-scale experiments and qualification testing of prototype-scale cables. The permanent equipment includes a 500 W supercritical helium refrigerator using a screw compressor and multistage turbine expanders. Helium storage for 250,000 cu ft of helium at 250 psi is provided. Initially, the cables will be tested in a horizontal cryostat some 250 ft long. High-voltage 60 Hz tests will be performed with the cable in a series resonant mode with a maximum line to ground capability of 240 kV, this is adequate for a 138 kV system design. Impulse testing up to about 650 kV is planned. The cable conductor will be energized by current transformers, initially at about 4 kA and later up to fault levels of 40 kA. The refrigerator is now at the site and testing on a dummy load will commence in the Fall of 1976. The cryostat will be installed in 1977 followed about a year later by the first cable tests.

  13. HBsAg, HBcAg, and combined HBsAg/HBcAg-based therapeutic vaccines in treating chronic hepatitis B virus infection

    Institute of Scientific and Technical Information of China (English)

    Sheikh Mohammad Fazle Akbar; Mamun Al-Mahtab

    2013-01-01

    BACKGROUND: As  the  host  immunity  is  diminished  in patients with chronic hepatitis B (CHB), different approaches have  been  used  to  up-regulate  their  immune  responses  to produce therapeutic effects. But, cytokines, growth factors and polyclonal  immune  modulators  could  not  exhibit  sufficient therapeutic  effects  in  these  patients.  Immune  therapy  with HBV-related antigens (vaccine therapy) has been used in CHB patients. But there is a paucity of information about the design of HBV antigen-based immune therapy in these patients. DATA  SOURCE: Preclinical  and  clinical  studies  on  immune therapy with HBsAg-based vaccine, HBcAg and combination of HBsAg/HBcAg-based vaccines have been discussed. RESULTS: HBsAg-based  prophylactic  vaccine  was  used  as an  immune  therapeutic  agent  in  CHB  patients;  however, monotherapy  with  HBsAg-based  immune  therapy  could not  lead  to  sustained  control  of  HBV  replication  and/or  liver damages.  HBsAg-based  vaccine  was  used  as  a  combination therapy  with  cytokines,  growth  factors,  and  antiviral  drugs. HBsAg-based  vaccine  was  also  used  for  cell-based  therapy. However,  satisfactory  therapeutic  effects  of  HBsAg-based vaccine could not be documented in CHB patients. In the mean time, evidences have supported that HBcAg-specific immunity is  endowed  with  antiviral  and  liver  protecting  capacities  in CHB  patients.  Recent  data  concentrate  on  the  clinical  use  of combined HBsAg- and HBcAg-based vaccines in CHB patients. CONCLUSION: Antigen-based  immune  therapy

  14. Monolayer solid of N-2/Ag(111)

    DEFF Research Database (Denmark)

    Bruch, L.W.; Hansen, Flemming Yssing

    1998-01-01

    An incommensurate monolayer solid of N-2/Ag(111) is modeled using extensive molecular-dynamics simulations. The conditions treated range from the low-temperature orientationally ordered solid to the melting of the solid. The properties are evaluated as a function of spreading pressure. Comparison...... is made to recent experimental data for N-2/Ag(111) and to results for N-2 adsorbed on graphite. Cu(110), and MgO(001). [S0163-1829(98)02715-5]....

  15. Antibacterial Ag/a-C nanocomposite coatings: The influence of nano-galvanic a-C and Ag couples on Ag ionization rates

    Energy Technology Data Exchange (ETDEWEB)

    Manninen, N.K., E-mail: nora.sousa@dem.uc.pt [SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); GRF-CFUM, Physics Department, University of Minho, Campus of Azurém, 4800-058 Guimarães (Portugal); Calderon, S. [SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); GRF-CFUM, Physics Department, University of Minho, Campus of Azurém, 4800-058 Guimarães (Portugal); Carvalho, I. [GRF-CFUM, Physics Department, University of Minho, Campus of Azurém, 4800-058 Guimarães (Portugal); CEB—Centre of Biological Engineering, LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, 4710-057 Braga (Portugal); Henriques, M. [CEB—Centre of Biological Engineering, LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, 4710-057 Braga (Portugal); Cavaleiro, A. [SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); Carvalho, S. [SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); GRF-CFUM, Physics Department, University of Minho, Campus of Azurém, 4800-058 Guimarães (Portugal)

    2016-07-30

    Highlights: • Amorphous carbon (a-C), Ag/a-C and Ag coatings were deposited by magnetron sputtering. • a-C/Ag coating shows antibacterial activity against S. epidermidis. • The formation of nano-galvanic couples in a-C/Ag enhances the Ag{sup +} ionization rate. • The Ag{sup +} ionization occurs along with Ag nanoparticles agglomeration in 0.9% NaCl. - Abstract: Biofilm formation has been pointed as a major concern in different industrial applications, namely on biomedical implants and surgical instruments, which has prompted the development of new strategies for production of efficient antimicrobial surfaces. In this work, nano-galvanic couples were created to enhance the antibacterial properties of silver, by embedding it into amorphous carbon (a-C) matrix. The developed Ag/a-C nanocomposite coatings, deposited by magnetron sputtering, revealed an outstanding antibacterial activity against Staphylococcus epidermidis, promoting a total reduction in biofilm formation with no bacteria counts in all dilution. The open circuit potential (OCP) tests in 0.9% NaCl confirmed that a-C shows a positive OCP value, in contrast to Ag coating, thus enhancing the ionization of biocidal Ag{sup +} due to the nano-galvanic couple activation. This result was confirmed by the inductively coupled plasma-optical emission spectroscopy (ICP-OES), which revealed a higher Ag ionization rate in the nanocomposite coating in comparison with the Ag coating. The surface of Ag/a-C and Ag coatings immersed in 0.9% NaCl were monitored by scanning electron microscopy (SEM) over a period of 24 h, being found that the Ag ionization determined by ICP-OES was accompanied by an Ag nanoparticles coalescence and agglomeration in Ag/a-C coating.

  16. Acceleration of polarized protons in the AGS

    Energy Technology Data Exchange (ETDEWEB)

    Tsoupas, N.; Ahrens, L.; Bai, M.; Brown, K.; Courant, E.; Glenn, J.W.; Huang, H.; Luccio, A.; MacKay, W.W.; Roser, T.; Schoefer, V.; Zeno, K.

    2010-02-25

    The high energy (s{sup 1/2} = 500 GeV) polarized proton beam experiments performed in RHIC, require high polarization of the proton beam. With the AGS used as the pre-injector to RHIC, one of the main tasks is to preserve the polarization of the proton beam, during the beam acceleration in the AGS. The polarization preservation is accomplished by the two partial helical magnets [1,2,3,4,5,6,7] which have been installed in AGS, and help overcome the imperfection and the intrinsic spin resonances which occur during the acceleration of protons. This elimination of the intrinsic resonances is accomplished by placing the vertical tune Q{sub y} at a value close to 8.98, within the spin-tune stop-band created by the snake. At this near integer tune the perturbations caused by the partial helical magnets is large resulting in large beta and dispersion waves. To mitigate the adverse effect of the partial helices on the optics of the AGS, we have introduced compensation quads[2] in the AGS. In this paper we present the beam optics of the AGS which ameliorates this effect of the partial helices.

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

    Directory of Open Access Journals (Sweden)

    Hui Ma

    2016-01-01

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

  18. Synthesis, structure, and magnetic properties of EuAgCd and YbAgCd

    Energy Technology Data Exchange (ETDEWEB)

    Fickenscher, T.; Kotzyba, G.; Hoffmann, R.D.; Poettgen, R. [Ludwig-Maximilians-Univ. Muenchen (Germany). Dept. Chemie

    2001-07-01

    New intermetallic compounds EuAgCd and YbAgCd were synthesized in quantitative yield by reaction of the elements in sealed tantalum tubes in a high-frequency furnace. Both compounds were investigated by X-ray diffraction on powders and single crystals: KHg{sub 2} type, Imma, a = 490.41(8), b = 771.0(1), c = 834.4(2) pm, wR2 = 0.0624, 255 F{sup 2} values, 12 variables for EuAgCd, and MgZn{sub 2} type, P6{sub 3}/mmc, a = 584.66(5), c = 946.83(9) pm, wR2 = 0.0502, 187 F{sup 2} values, 11 variables for YbAgCd. Owing to the very small difference in scattering power, no long range ordering of the silver and cadmium atoms is evident from the X-ray data, although Ag-Cd ordering is expected. The silver and cadmium atoms randomly occupy the mercury and zinc positions of the KHg{sub 2} and MgZn{sub 2} type structures, respectively. In EuAgCd the [AgCd] substructure consists of strongly puckered, orthorhombically distorted Ag{sub 3}Cd{sub 3} hexagons, while a three-dimensional network of face- and corner-sharing tetrahedra is observed in YbAgCd. The rare earth atoms fill the space between the Ag{sub 3}Cd{sub 3} hexagons (EuAgCd) or within the three-dimensional tetrahedral network (YbAgCd). Magnetic susceptibility measurements indicate Pauli paramagnetism for YbAgCd and Curie-Weiss behavior above 60 K for EuAgCd with an experimental magnetic moment of 7.82(3) {mu}{sub B}/Eu indicating divalent ytterbium and europium. Ferromagnetic ordering at T{sub C} = 28.0(5) K is observed for EuAgCd. At 2 K and 5 T the saturation magnetization is 5.85(5) {mu}{sub B}/Eu. (orig.)

  19. High Visible Photoelectrochemical Activity of Ag Nanoparticle-Sandwiched CdS/Ag/ZnO Nanorods.

    Science.gov (United States)

    Yang, Xu; Li, Hui; Zhang, Wu; Sun, Mingxuan; Li, Lequn; Xu, Ning; Wu, Jiada; Sun, Jian

    2017-01-11

    We report on the sensitizing of CdS-coated ZnO (CdS/ZnO) nanorods (NRs) by Ag nanoparticles (NPs) embedded between the CdS coating and the ZnO nanorod and the improved optical and photoelectrochemical properties of the Ag NP-sandwiched nanostructure CdS/Ag/ZnO NRs. The CdS/Ag/ZnO NRs were fabricated by growing Ag NPs on hydrothermally grown ZnO NRs and subsequently depositing CdS coatings followed by subsequent N2 annealing. The structure of the fabricated CdS/Ag/ZnO NRs was characterized by field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman backscattering, revealing that the ZnO NRs and the CdS coatings are both structured with hexagonal wurtzite and the Ag NPs contact well with ZnO and CdS. Optical properties were evaluated by measuring optical absorption and photoluminescence, showing that the Ag NPs behave well as sensitizers for optical property improvement and the CdS/Ag/ZnO NRs exhibit better photoresponse in a wide spectral region than CdS/ZnO because of plasmon-enhanced absorption due to the embedment of Ag NPs. The Ag NPs also serve as electron relays from CdS to ZnO, facilitating electron transfer from the CdS coatings to the ZnO NRs. The excellent photoresponse and efficient electron transfer make the CdS/Ag/ZnO NRs highly photoelectrochemically active. The CdS/Ag/ZnO NRs fabricated on indium-tin oxide present much better photoelectrochemical performance as photoanodes working in the visible region than CdS/ZnO NRs without Ag NPs. Under visible illumination, a maximum optical-to-chemical conversion efficiency of 3.13% is obtained for CdS/Ag/ZnO NR photoanodes against 1.35% for CdS/ZnO NR photoanodes.

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

    NARCIS (Netherlands)

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

    1986-01-01

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

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

    Science.gov (United States)

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

    2016-10-01

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

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  3. Beet Juice-Induced Green Fabrication of Plasmonic AgCl/Ag Nanoparticles

    Science.gov (United States)

    A simple, green, and fast approach (complete within 5 min) was explored for the fabrication of hybrid AgCl/Ag plasmonic nanoparticles under microwave (MW) irradiation. In this method, beet juice served as a reducing reagent, which is an abundant sugar-rich agricultural produce. I...

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

    Directory of Open Access Journals (Sweden)

    Takeo Ohno

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-01

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

  6. Effects of Ag nanomaterials (NM300K) and Ag salt (AgNO3) can be discriminated in a full life cycle long term test with Enchytraeus crypticus

    DEFF Research Database (Denmark)

    Bicho, Rita C; Ribeiro, Tânia; Rodrigues, Natália P;

    2016-01-01

    . Results showed that effects were higher compared to the standard reproduction test, which is shorter and does not cover the FLC. Both Ag forms caused a reduction on hatching success, juvenile and adult survival and reproduction with similar ECx. Differences between AgNO3 and Ag NM300K could...

  7. Determination of isothermal section of Ag-Ti-Zr ternary system at 1 023 K

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The isothermal section of Ag-Ti-Zr ternary system at 1023 K was determined by diffusion triple and electron probe microanalysis. The results indicate that four binary intermetallic phases of AgTi, AgTi2, AgZr and AgZr2 are found in Ag-Ti-Zr ternary system at 1 023 K. AgZr2 and AgTi2 form a continuous solid solution, namely Ag(Ti,Zr)2. Four three-phase regions: AgTi+AgZr + Ag, AgTi +AgZr + Ag (Ti, Zr)2, α-Zr +β3(Ti, Zr)+ Ag (Ti, Zr)2 and α-Ti +β(Ti, Zr)+ Ag (Ti, Zr)2 exist in the isothermal section. No ternary compound is observed.

  8. Noble-metal Ag nanoparticle chains: annealing Ag/Bi superlattice nanowires in vacuum

    Science.gov (United States)

    Xu, Shao Hui; Fei, Guang Tao; You, Qiao; Gao, Xu Dong; Huo, Peng Cheng; De Zhang, Li

    2016-09-01

    One-dimensional noble-metal Ag nanoparticle chains have been prepared by electrodepositing Ag/Bi superlattice nanowires in a porous anodic alumina oxide (AAO) template and following an annealing process in vacuum. It is found that Bi, as a sacrificial metal, can be removed completely after annealing at 450 °C with a vacuum degree of 10-5 Torr. The regulation of particle size, shape and interparticle spacing of Ag NP chains has been realized by adjusting the segment length of the Ag/Bi superlattice nanowires and the annealing condition. With an extension of the annealing time, it is observed that Ag particles display the transform trend from ellipsoid to sphere. Our findings could inspire further investigation on the design and fabrication of metal nanoparticle chains.

  9. Observation of nonvolatile resistive memory switching characteristics in Ag/graphene-oxide/Ag devices.

    Science.gov (United States)

    Venugopal, Gunasekaran; Kim, Sang-Jae

    2012-11-01

    In this paper, we report highly stable and bipolar resistive switching effects of Ag/Graphene oxide thinfilm/Ag devices. The graphene-oxide (GO) thinfilms were prepared on Ag/SiO2/Si substrates by spin-coating technique. The Ag/GO/Ag devices showed a steady and bipolar resistive switching characteristic. The resistance switching from low resistance state (LRS) and high resistance state (HRS) with the resistance ratio of HRS to LRS of about 10 which was attained at a voltage bias of 0.1 V. Based on the filamentary conduction model, the dominant conduction mechanism of switching effect was well explained. Our results show GO can be a promising candidate for future development of nonvolatile memory devices.

  10. Abnormal growth of Ag3Sn intermetallic compounds in Sn-Ag lead-free solder

    Institute of Scientific and Technical Information of China (English)

    SHEN Jun; LIU Yongchang; GAO Houxiu

    2006-01-01

    The abnormal growth of Ag3Sn intermetallic compounds in eutectic Sn-3.5% Ag solder was investigated through high-temperature aging treatment. Microstructural evolutions of this solder before and after the aging treatment were observed by optical microscopy and scanning electron microscopy. Precise differential thermal analysis was made to study the changes in enthalpies of the solder under different conditions. The results reveal that the water-cooled solder is in metastable thermodynamic state due to the high free energy of Ag3Sn nanoparticles, which sporadically distribute in the matrix as second-phase. The second-phase Ag3Sn nanoparticles aggregate rapidly and grow to form bulk intermetallic compounds due to the migration of grain boundary between primary Sn-rich phase and the Ag3Sn nanoparticles during high temperature aging treatment.

  11. Comparative Study on Performance of Engineering Ag/AgC1 Reference Electrode%工程用Ag/AgCl参比电极性能对比研究

    Institute of Scientific and Technical Information of China (English)

    尹鹏飞; 马长江; 许立坤

    2011-01-01

    使用热浸涂法和粉压法制备了工程用Ag/AgCl参比电极.电化学性能测试表明热浸涂法和粉压法制备的Ag/AgCl参比电极的电位稳定性都比较好,但热浸涂法制备的Ag/AgCl参比电极的耐极化性能优于粉压法制备的Ag/AgCl参比电极.热浸涂法和粉压法制备的Ag/AgCl参比电极的温度系数都比较小,温度响应特性较好.海水流速对热浸涂法和粉压法制备的Ag/AgCl参比电极的电位有明显影响,参比电极封装外壳可改善电极在流动海水中的电位稳定性能.%Ag/AgCl reference electrodes for engineering were prepared with powder press and thermal dip-coating method. The electrochemical test result showed that the potential stability of them were both good; the Ag/AgCl reference electrode prepared with thermal dip-coating method has smaller polarization resistance than the one prepared with powder press method; the temperature coefficient of Ag/AgCl reference electrodes prepared with thermal dip-coating and powder press method are both small. It showed that the relative flow velocity of seawater has obvious effect on the electrode potential; encapsulation of reference electrodes can- improve their potential stability in flowing seawater.

  12. Facile synthesis of AgCl/polydopamine/Ag nanoparticles with in-situ laser improving Raman scattering effect

    Science.gov (United States)

    Zhang, Yan; Zhang, Wenqi; Wang, Lin; Wang, Feng; Yang, Haifeng

    2017-01-01

    We reported a simple and fast method to prepare a composite material of polydopamine (PDA) adlayer covered cubic AgCl core, which was inlaid with Ag nanoparticles (NPs), shortly named as AgCl/PDA/AgNPs. The resultant AgCl/PDA/AgNPs could be employed as surface-enhanced Raman scattering (SERS) substrate for in-situ detection and the SERS activity could be further greatly improved due to the production of more AgNPs upon laser irradiation. With 4-mercaptopyridine (4-Mpy) as the probe molecule, the enhancement factor could reach 107. Additionally, such SERS substrate shows good reproducibility with relative standard deviation of 7.32% and long term stability (after storage for 100 days under ambient condition, SERS intensity decay is less than 25%). In-situ elevating SERS activity of AgCl/PDA/AgNPs induced by laser may be beneficial to sensitive analysis in practical fields.

  13. Comp ositionally Graded Microstructure for Ag-Fe Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Chandan Srivastava∗; K. V. L. Sushma

    2012-01-01

    Ag-Fe nanoparticles with a highly Ag rich average composition were synthesized by the sono-chemical route. Silver-iron system exhibits a wide miscibility gap in the bulk materials. Interestingly, a graded compositional profile along the nanoparticle radius was observed. Regions at and near the surface of the nanoparticle contained both Ag and Fe atoms. The composition got relatively deficient Fe towards the center of the particle with particle core made up of pure Ag. Alloying of Ag and Fe is confirmed by the absence of diffraction signal corresponding to pure Fe phase and presence of a paramagnetic phase in nanoparticles containing a diamagnetic (Ag) and ferromagnetic (Fe) elements.

  14. Enhanced Raman scattering of graphene on Ag nanoislands

    Institute of Scientific and Technical Information of China (English)

    HU Wei; HUANG ZhiYi; ZHOU YingHui; CAI WeiWei; KANG JunYong

    2014-01-01

    The effect of Ag nanoislands on the Raman of graphene was investigated in this work.Compared with that on the bare silicon wafer,Raman enhancement was observed in the graphene film that covered on Ag/Si surface with nanoscale Ag islands,which would be induced by the localized plasmon resonance in Ag nanostructures.The interaction between the graphene sheet and Ag/Si substrate was further studied.The peak shift and line shape of Raman spectroscopy indicated a nonuniform strain distribution in the Ag/Si supported graphene film.

  15. Synthesis, characterization and antimycobacterial activity of Ag(I)-aspartame, Ag(I)-saccharin and Ag(I)-cyclamate complexes.

    Science.gov (United States)

    Cavicchioli, Maurício; Leite, Clarice Q F; Sato, Daisy N; Massabni, Antonio C

    2007-10-01

    The present work describes the synthesis and antimycobacterial activity of three Ag(I)-complexes with the sweeteners aspartame, saccharin, and cyclamate as ligands, with the aim of finding new candidate substances for fighting tuberculosis and other mycobacterial infections. The minimal inhibitory concentration of these three complexes was investigated in order to determine their in-vitro antimycobacterial activity against Mycobacterium tuberculosis, Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium malmoense, and Mycobacterium kansasii. The MIC values were determined using the Microplate Alamar Blue Assay. The best MIC values found for the complexes were 9.75 microM for Ag(I)-aspartame against M. kansasii and 15.7 microM for Ag(I)-cyclamate against M. tuberculosis.

  16. BiPO4 photocatalyst employing synergistic action of Ag/Ag3PO4 nanostructure and graphene nanosheets

    Science.gov (United States)

    Mohaghegh, N.; Rahimi, E.

    2016-06-01

    Graphene-supported BiPO4/Ag/Ag3PO4 photocatalyst has been fabricated by simple hydrothermal and impregnation reaction. In BiPO4/Ag/Ag3PO4 based on Reduced Graphene Oxide (RGO), this network renders numerous pathways for rapid mass transport, strong adsorption and multireflection of incident light; meanwhile, the interface between BiPO4/Ag/Ag3PO4 and RGO increases the active sites and electron transfer rate. BiPO4/Ag/Ag3PO4 based on RGO noticeably exhibited high photocatalytic activity than that of BiPO4/Ag/Ag3PO4 and P25 under visible light irradiation for cationic dye (Rhodamine B), anionic dye (methyl orange) and 4-chlorophenol (4-CP) as a neutral pollutant, which are usually difficult to be degraded over the other catalysts. This enhanced photocatalytic activity of Graphene-supported BiPO4/Ag/Ag3PO4 for all pollutants could be mainly ascribed to the reinforced charge transfer from BiPO4/Ag/Ag3PO4 to RGO, which suppresses the recombination of electron/hole pairs. Besides that, this photocatalyst can be used repetitively with a high photocatalytic activity and no apparent loss of activity occurs. The results reveal that the RGO nanosheets work as a photocatalyst promoter during the photocatalytic reaction, leading to an improved photocatalytic activity.

  17. Template synthesis of Ag/AgCl microrods and their efficient visible light-driven photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hua; Xiao, Liang; Huang, Jianhua, E-mail: jhhuang@zstu.edu.cn

    2014-09-15

    Highlights: • Preparation ofAg/AgCl microrods by reaction of Ag{sub 2}WO{sub 4} microrods with NaCl solution. • Generation of metallic Ag is induced by the ambient light in the synthesis process. • Ag/AgCl shows excellent visible light-driven photodegradation of organic dyes. - Abstract: Ag/AgCl microrods, aggregated by nanoparticles with a diameter ranging from 100 nm to 2 μm, were prepared by an ion-exchange reaction at 80 °C between Ag{sub 2}WO{sub 4} template and NaCl solution. The existence of metallic Ag species was confirmed by XRD, DRS and XPS measurements. Ag/AgCl microrods showed excellent photocatalytic activity for the degradation of rhodamine B and methylene blue under visible light irradiation. The degradation rate constants of rhodamine B and methylene blue are 0.176 and 0.114 min{sup −1}, respectively. The cycling photodegradation experiments suggest that Ag/AgCl microds could be employed as stable plasmonic photocatalysts for the degradation of organic dyes under visible light irradiation.

  18. Effect of cysteine and humic acids on bioavailability of Ag from Ag nanoparticles to a freshwater snail

    Science.gov (United States)

    Luoma, Samuel N.; Tasha Stoiber,; Croteau, Marie-Noele; Isabelle Romer,; Ruth Merrifeild,; Lead, Jamie

    2016-01-01

    Metal-based engineered nanoparticles (NPs) will undergo transformations that will affect their bioavailability, toxicity and ecological risk when released to the environment, including interactions with dissolved organic material. The purpose of this paper is to determine how interactions with two different types of organic material affect the bioavailability of silver nanoparticles (AgNPs). Silver uptake rates by the pond snail Lymnaea stagnalis were determined after exposure to 25 nmol l-1 of Ag as PVP AgNPs, PEG AgNPs or AgNO3, in the presence of either Suwannee River humic acid or cysteine, a high-affinity thiol-rich organic ligand. Total uptake rate of Ag from the two NPs was either increased or not strongly affected in the presence of 1 – 10 mg 1-1 humic acid. Humic substances contain relatively few strong ligands for Ag explaining their limited effects on Ag uptake rate. In contrast, Ag uptake rate was substantially reduced by cysteine. Three components of uptake from the AgNPs were quantified in the presence of cysteine using a biodynamic modeling approach: uptake of dissolved Ag released by the AgNPs, uptake of a polymer or large (>3kD) Ag-cysteine complex and uptake of the nanoparticle itself. Addition of 1:1 Ag:cysteine reduced concentrations of dissolved Ag, which contributed to, but did not fully explain the reductions in uptake. A bioavailable Ag-cysteine complex (> 3kD) appeared to be the dominant avenue of uptake from both PVP AgNPs and PEG AgNPs in the presence of cysteine. Quantifying the different avenues of uptake sets the stage for studies to assess toxicity unique to NPs.

  19. Isomorphism and solid solutions among Ag- and Au-selenides

    Energy Technology Data Exchange (ETDEWEB)

    Palyanova, Galina A.; Seryotkin, Yurii V. [Sobolev Institute of Geology and Mineralogy, Novosibirsk (Russian Federation); Novosibirsk State University (Russian Federation); Kokh, Konstantin A., E-mail: k.a.kokh@gmail.com [Sobolev Institute of Geology and Mineralogy, Novosibirsk (Russian Federation); Novosibirsk State University (Russian Federation); Tomsk State University (Russian Federation); Bakakin, Vladimir V. [Nikolaev Institute of Inorganic Chemistry, Novosibirsk (Russian Federation)

    2016-09-15

    Au-Ag selenides were synthesized by heating stoichiometric mixtures of elementary substances of initial compositions Ag{sub 2−x}Au{sub x}Se with a step of x=0.25 (0≤x≤2) to 1050 °C and annealing at 500 °C. Scanning electron microscopy, optical microscopy, electron microprobe analysis and X-ray powder diffraction methods have been applied to study synthesized samples. Results of studies of synthesized products revealed the existence of three solid solutions with limited isomorphism Ag↔Au: naumannite Ag{sub 2}Se – Ag{sub 1.94}Au{sub 0.06}Se, fischesserite Ag{sub 3}AuSe{sub 2} - Ag{sub 3.2}Au{sub 0.8}Se{sub 2} and gold selenide AuSe - Au{sub 0.94}Ag{sub 0.06}Se. Solid solutions and AgAuSe phases were added to the phase diagram of Ag-Au-Se system. Crystal-chemical interpretation of Ag-Au isomorphism in selenides was made on the basis of structural features of fischesserite, naumannite, and AuSe. - Highlights: • Au-Ag selenides were synthesized. • Limited Ag-Au isomorphism in the selenides is affected by structural features. • Some new phases were introduced to the phase diagram Ag-Au-Se.

  20. Luminescent Property of a Supramolecular Silver(I)-Thiolate Complex Based on Secondary Ag-S Interactions and Hydrogen Bonds

    Institute of Scientific and Technical Information of China (English)

    SU,Wei-Pinga(苏伟平); SU,Wei-Ping; HONG,Mao-Chun(洪茂椿); HONG,Mao-Chun; CAO,Rong (曹荣); CAO,Rong; WENG,Jia-Bao(翁家宝); WENG,Jia-Bao; ZHOU,Zhong-Yuan(周忠远); ZHOU,Zhong-Yuan; CHAN,S.C.Albert(陈新滋); CHAN,S.C.Albert

    2001-01-01

    The supramolecular silver(I)-thiolate complex [Ag(μ2-SC4N2I4)2(SCN)]n has been prepared from the reaction of AgSCN and p iyrimidine-2-thiol in DMF. X-ray diffraction analysis shows that the supramolecular structure exhibits onedimemional chain through the secondary Ag-S interactions and the chains are further linked by strong hydrogen bonds to form a three dimensional network. The luminescenee effect from the silver-centered state of SAg LMCT in solid state is different from that in solution due to the secondary Ag-S interactions.

  1. Bipolar Ag-Zn battery

    Science.gov (United States)

    Giltner, L. John

    1994-02-01

    The silver-zinc (AgZn) battery system has been unique in its ability to safely satisfy high power demand applications with low mass and volume. However, a new generation of defense, aerospace, and commercial applications will impose even higher power demands. These new power demands can be satisfied by the development of a bipolar battery design. In this configuration the power consuming, interelectrode current conductors are eliminated while the current is then conducted via the large cross-section electrode substrate. Negative and positive active materials are applied to opposite sides of a solid silver foil substrate. In addition to reducing the weight and volume required for a specified power level, the output voltage performance is also improved as follows. Reduced weight through: elimination of the plastic cell container; elimination of plate leads and intercell connector; and elimination of internal plate current collector. Increased voltage through: elimination of resistance of current collector; elimination of resistance of plate lead; and elimination of resistance of intercell connector. EPI worked previously on development of a secondary bipolar silver zinc battery. This development demonstrated the electrical capability of the system and manufacturing techniques. One difficulty with this development was mechanical problems with the seals. However, recent improvements in plastics and adhesives should eliminate the major problem of maintaining a seal around the periphery of the bipolar module. The seal problem is not as significant for a primary battery application or for a requirement for only a few discharge cycles. A second difficulty encountered was with activation (introducing electrolyte into the cell) and with venting gas from the cell without loss of electrolyte. During previous work, the following projections for energy density were made from test data for a high power system which demonstrated in excess of 50 discharge/charge cycles. Projected

  2. Spectrophotometry of the shell around AG Carinae

    Science.gov (United States)

    Mitra, P. Mila; Dufour, Reginald J.

    1990-01-01

    Spatially-resolved long-slit spectrophotometry are presented for two regions of the shell nebula around the P-Cygni variable star AG Carinae. The spectra cover the 3700-6800 A wavelength range. Emission-line diagnostics are used to derive extinction, electron temperatures, and densities for various positions in the nebula. The chemical abundances and ionization structure are calculated and compared with other types of planetary nebulae and shells around other luminous stars. It is found that the N/O and N/S ratios of Ag Car are high compared to solar neighborhood ISM values. The O/H depletion found for the AG Car shell approaches that found in the condensations of the Eta Car system.

  3. 异常核型者的Ag-NOR和Ag-AA分析%Analysis of Ag-NOR-Ag-AA for patients with chromosome anomalies

    Institute of Scientific and Technical Information of China (English)

    彭惠民; 唐吟宇; 郭玉萍; 张静

    2000-01-01

    为了解异常核型者的rRNA基因活性及近端着丝粒染色体联合频率的变化规律,用硝酸银染色法对14例染色体罗伯逊易位携带者,26例klinefelter综合征患者,16例Turner综合征患者及30名正常对照,进行银染核仁组织者区(Ag-NOR)和银染近端着丝粒染色体联合(Ag-AA)频率的研究.发现Kinefelter综合征和Turner综合征患者的Ag-NOR/细胞(6.93、6.49)及Ag-AA细胞(1.02、1.05)均显著高于对照(5.30、0.60).罗伯逊易位携带者Ag+NOR/细胞(5.10)与对照无显著性差异,Ag-AA/细胞(1.21)显著高于对照.提示罗伯逊易位丢失的rRNA基因可由其他近端着丝粒染色体上的rRNA基因增加转录活性来补偿,近端着丝粒染色体联合频率的增加可能与染色体不分离或易位的形成有关.

  4. Optical absorption spectra of Ag-11 isomers

    DEFF Research Database (Denmark)

    Martinez, Jose Ignacio; Fernandez, E. M.

    2009-01-01

    The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground-stale confi......The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground...

  5. Effect of Ag shapes and surface compositions on the photocatalytic performance of Ag/ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jia [Hubei Collaborative Innovation Center for High-efficiency Utilization of Solar Energy, Hubei University of Technology, Wuhan (China); School of Mechanical Engineering, Hubei University of Technology, Wuhan (China); Hubei Provincial Key Laboratory of Green Materials for Light Industry, Hubei University of Technology, Wuhan (China); Wang, Huihu, E-mail: wanghuihu@mail.hbut.edu.cn [Hubei Collaborative Innovation Center for High-efficiency Utilization of Solar Energy, Hubei University of Technology, Wuhan (China); School of Mechanical Engineering, Hubei University of Technology, Wuhan (China); Hubei Provincial Key Laboratory of Green Materials for Light Industry, Hubei University of Technology, Wuhan (China); Dong, Shijie [School of Mechanical Engineering, Hubei University of Technology, Wuhan (China); Hubei Provincial Key Laboratory of Green Materials for Light Industry, Hubei University of Technology, Wuhan (China); Wang, Fanqiang; Dong, Yifan [School of Mechanical Engineering, Hubei University of Technology, Wuhan (China)

    2014-12-25

    Highlights: • Ag/ZnO nanorods were synthesized via photoreduction and hydrothermal methods. • Ag presents nanosheet and nanoparticle shapes in different synthesis methods. • SPR effect and Ag{sup +} is observed only for Ag/ZnO prepared by hydrothermal method. • Ag nanosheets modified ZnO shows the high activity under UV–Vis. irradiation. • Only Ag nanoparticles modified ZnO nanorods has the visible-light-driven activity. - Abstract: Photoreduction and hydrothermal methods were used respectively to prepare Ag surface modified ZnO nanorods in this paper. The surface microstructure and photocatalytic performance of Ag/ZnO nanorods for methyl orange degradation were evaluated in detail. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS) and UV–Vis. diffuse reflectance spectroscopy (DRS) were used for microstructure analysis of as-prepared Ag/ZnO nanorods. FESEM images showed that Ag presented nanosheets in Ag/ZnO sample (AZP) prepared by photoreduction method, while it exhibited nanoparticles in the sample (AZH) using hydrothermal method. DRS studies clearly displayed surface plasmon resonance (SPR) effect of Ag in AZH samples. Furthermore, there was a red shift on absorption edge for AZH samples compared with bare ZnO and AZP samples. The XPS results revealed that Ag{sup +} ions existed on the surface of AZH samples. In contrast to AZH sample, AZP sample demonstrated the higher photocatalytic activity under UV–Vis. light illumination. However, it was interesting that AZH samples exhibited the visible-light-driven photocatalytic activity, which may be due to the cooperation role of the existence of Ag{sup +} ions and SPR effect of Ag nanoparticles. All these results illustrated that the shapes and surface compositions of Ag may be important factors that influence the photocatalytic performance of Ag/ZnO nanorods. The surface microstructure related photocatalytic mechanism was finally

  6. Hierarchical Ag mesostructures for single particle SERS substrate

    Science.gov (United States)

    Xu, Minwei; Zhang, Yin

    2017-01-01

    Hierarchical Ag mesostructures with highly rough surface morphology have been synthesized at room temperature through a simple seed-mediated approach. Electron microscopy characterizations indicate that the obtained Ag mesostructures exhibit a textured surface morphology with the flower-like architecture. Moreover, the particle size can be tailored easily in the range of 250-500 nm. For the growth process of the hierarchical Ag mesostructures, it is believed that the self-assembly mechanism is more reasonable rather than the epitaxial overgrowth of Ag seed. The oriented attachment of nanoparticles is revealed during the formation of Ag mesostructures. Single particle surface enhanced Raman spectra (sp-SERS) of crystal violet adsorbed on the hierarchical Ag mesostructures were measured. Results reveal that the hierarchical Ag mesostructures can be highly sensitive sp-SERS substrates with good reproducibility. The average enhancement factors for individual Ag mesostructures are estimated to be about 106.

  7. Preparation and Characterization of Highly Efficient and Stable Visible-Light-Responsive Photocatalyst AgBr/Ag3PO4

    Directory of Open Access Journals (Sweden)

    Zhang Jinfeng

    2013-01-01

    Full Text Available AgBr/Ag3PO4 photocatalyst was synthesized using a facile coprecipitation method. The photocatalyst was characterized by X-ray powder diffraction (XRD, UV-Vis diffuse reflectance spectroscopy (DRS, scanning electron microscopy (SEM, Brunauer-Emmett-Teller (BET surface areas, and photoluminescence (PL technique. The activity of the photocatalyst was evaluated by the degradation of methyl orange (MO and rhodamine B (RhB. The results showed that the prepared AgBr/Ag3PO4 exhibited excellent performance and much higher photocatalytic activity than the single one under visible-light irradiation. The optimum mole ratio of Br/P in AgBr/Ag3PO4 samples is 0.3. The prepared AgBr/Ag3PO4 photocatalyst was transformed to Ag/AgBr/Ag3PO4 system with excellent property and good stability in the photocatalytic process. The possible mechanisms of the enhanced photocatalytic activity for the AgBr/Ag3PO4 were also discussed in detail.

  8. Bifunctional AgCl/Ag composites for SERS monitoring and low temperature visible light photocatalysis degradation of pollutant

    Science.gov (United States)

    Dong, Lihong; Zhu, Junyi; Xia, Guangqing

    2014-12-01

    With the assistance of Polyvinylpyrrolidone (PVP), AgCl/Ag composites were fabricated in N, N-Dimethylformamide (DMF) solvent via a photoactivated route. The size of AgCl particles was in the range of 500 nm to 1 μm and the Ag particle's diameter was about 10-20 nm. Different from those core-shell structures reported before, the Ag nanoparticles were dispersed uniformly both on the surface and in the body of AgCl particles. The generation of such kind of composites was resulted from the reducing ability of DMF and light irradiation during the formation of AgCl particles. The as-obtained AgCl/Ag composites presented great activity for both surface-enhanced Raman scattering (SERS) detection and visible light photocatalytic degradation of organic dyes. Additionally, the AgCl/Ag composites could maintain high photocatalytic activity even though the ambient temperature was as low as 15 °C and recycle photocatalysis experiments indicated that the photocatalyst exhibited higher stability. Such kind of AgCl/Ag composites holds great potential for environmental monitoring devices and pollutant treatments.

  9. Effect of Ag in structural, electrical and magnetic properties of Ag-sheated Bi-2223 wires

    Directory of Open Access Journals (Sweden)

    D Sohrabi

    2009-08-01

    Full Text Available  In this study, the superconducting properties of Bi-2223/Ag wires, made by the PIT method have been studied. Powder samples were prepared using conventional solid state reaction method. After calcination, samples with different Ag percent (0, 5, 10, 15, 20, and 25 prepared and sintered at 830 °C. It was shown that Ag addition has not only affected the formation of the desired Bi-2223 phase and the microstructure of these wires, but also influenced on the critical current density (JC and critical temperature.

  10. A multi-wire beam profile monitor in the AGS

    Energy Technology Data Exchange (ETDEWEB)

    Huang, H.; Buxton, W.; Castillo, V.; Glenn, J.W. [and others

    1997-07-01

    A multi-wire beam profile monitor which can be used to directly monitor and control the optical matching between the Booster and AGS rings has been installed and tested in the AGS. Placement of a multi-wire monitor directly in the AGS provides profile measurements taken upon injection and the first two or more revolutions of the beam. The data from such measurements can be used to determine the optical properties of the beam transport line leading into the AGS.

  11. Effect of Ag+ and PO43- ratios on the microstructure and photocatalytic activity of Ag3PO4

    Science.gov (United States)

    Qin, Jiaqian; Zhang, Xinyu; Yang, Chengwu; Song, Aijun; Zhang, Bing; Rajendran, Saravanan; Ma, Mingzhen; Liu, Riping

    2016-09-01

    In this work, the catalyst silver phosphate (Ag3PO4) with different initial ratios of Ag+ and PO43- in aqueous solution was synthesized by a simple precipitation method from AgNO3 and NH4H2PO4 which were used as the precursor. After that, the prepared samples were characterized by different techniques such as field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy (UV-DRS) and decomposition evolution of rhodamine B (RhB) solution. The results indicate that the initial ratios of Ag+/PO43- in aqueous solution can modify the morphology and also it can significantly affect the photocatalytic performance. During photocatalytic process, the rich Ag+ ion Ag3PO4 can form the surface plasmon resonance (SPR) of Ag nanoparticles, which inhibit the reduction of Ag3PO4 resulting in higher photocatalytic activity and stability.

  12. Analysis of the complexation reaction between Ag+ and ethylene

    NARCIS (Netherlands)

    Nymeijer, Kitty; Visser, Tymen; Brilman, Wim; Wessling, Matthias

    2004-01-01

    In the present work the reversible, bimolecular (1,1) reaction between ethylene and Ag+ in concentrated AgNO3(aq) solutions is analyzed. Due to interactions between the positively charged Ag+ ions and the negatively charged NO3- ions, the silver nitrate is not completely dissociated and the actual f

  13. AGS experiments -- 1996, 1997, 1998, 1999. Fifteenth edition

    Energy Technology Data Exchange (ETDEWEB)

    Lo Presti, P.

    1999-03-01

    This report is a compilation of two-page summaries for AGS experiments for FY 1996, FY 1997, FY 1998, FY 1999. The bulk of the experiments are for high energy physics and nuclear physics programs. Also included are the run schedules for the AGS for each of those years and a listing of publications of AGS experiments for 1982--1999.

  14. Thermal stability of substitutional ag in CdTe

    NARCIS (Netherlands)

    Jahn, SG; Hofsass, H; Restle, M; Ronning, C; Quintel, H; BharuthRam, K; Wahl, U

    1996-01-01

    The thermal stability of substitutional Ag in CdTe was deduced from lattice location measurements at different temperatures. Substitutional Ag probe atoms were generated via transmutation doping from radioactive Cd isotopes. The lattice sites of Ag isotopes were determined by measuring the channelin

  15. Antibacterial Ag/a-C nanocomposite coatings: The influence of nano-galvanic a-C and Ag couples on Ag ionization rates

    Science.gov (United States)

    Manninen, N. K.; Calderon, S.; Carvalho, I.; Henriques, M.; Cavaleiro, A.; Carvalho, S.

    2016-07-01

    Biofilm formation has been pointed as a major concern in different industrial applications, namely on biomedical implants and surgical instruments, which has prompted the development of new strategies for production of efficient antimicrobial surfaces. In this work, nano-galvanic couples were created to enhance the antibacterial properties of silver, by embedding it into amorphous carbon (a-C) matrix. The developed Ag/a-C nanocomposite coatings, deposited by magnetron sputtering, revealed an outstanding antibacterial activity against Staphylococcus epidermidis, promoting a total reduction in biofilm formation with no bacteria counts in all dilution. The open circuit potential (OCP) tests in 0.9% NaCl confirmed that a-C shows a positive OCP value, in contrast to Ag coating, thus enhancing the ionization of biocidal Ag+ due to the nano-galvanic couple activation. This result was confirmed by the inductively coupled plasma-optical emission spectroscopy (ICP-OES), which revealed a higher Ag ionization rate in the nanocomposite coating in comparison with the Ag coating. The surface of Ag/a-C and Ag coatings immersed in 0.9% NaCl were monitored by scanning electron microscopy (SEM) over a period of 24 h, being found that the Ag ionization determined by ICP-OES was accompanied by an Ag nanoparticles coalescence and agglomeration in Ag/a-C coating.

  16. Evidence for enhancement of critical current by intergrain Ag in YBaCuO-Ag ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Dwir, B.; Affronte, M.; Pavuna, D.

    1989-07-24

    We report the evidence for enhancement of critical current density /ital J//sub /ital c// by /similar to/50%, which occurs when /similar to/10 wt. % Ag is added to Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7/minus//delta// ceramics. The maximal /ital J//sub /ital c// (/similar to/700 A/cm/sup 2/ at /ital T/=77 K) appears simultaneously with maximum YBaCuO compactness in the samples. The silver fills the intergranular space (holes) without Cu substitution, and the critical temperature /ital T//sub /ital c// is not reduced from the bulk value (/similar to/91 K). Normal-state resistivity of Ag-YBaCuO samples is decreased by an order of magnitude, and samples exhibit improved contact resistance and resistance to water. While the critical density is improved by adding /similar to/10 wt. % Ag, it decreases at higher Ag concentrations.

  17. Surface-enhanced Raman scattering from AgNP-graphene-AgNP sandwiched nanostructures.

    Science.gov (United States)

    Wu, Jian; Xu, Yijun; Xu, Pengyu; Pan, Zhenghui; Chen, Sheng; Shen, Qishen; Zhan, Li; Zhang, Yuegang; Ni, Weihai

    2015-11-07

    We developed a facile approach toward hybrid AgNP-graphene-AgNP sandwiched structures using self-organized monolayered AgNPs from wet chemical synthesis for the optimized enhancement of the Raman response of monolayer graphene. We demonstrate that the Raman scattering of graphene can be enhanced 530 fold in the hybrid structure. The Raman enhancement is sensitively dependent on the hybrid structure, incident angle, and excitation wavelength. A systematic simulation is performed, which well explains the enhancement mechanism. Our study indicates that the enhancement resulted from the plasmonic coupling between the AgNPs on the opposite sides of graphene. Our approach towards ideal substrates offers great potential to produce a "hot surface" for enhancing the Raman response of two-dimensional materials.

  18. Biochemical Synthesis of Ag/AgCl Nanoparticles for Visible-Light-Driven Photocatalytic Removal of Colored Dyes

    OpenAIRE

    Xiyun Zhao; Jie Zhang; Binsong Wang; Amir Zada; Muhammad Humayun

    2015-01-01

    Photocatalytic removal of organic pollution such as waste colored dyes was a promising technique for environment technique. However, effective photocatalysts were needed to enhance the photocatalytic efficiency. Ag/AgCl was regarded as high performance catalyst for photocatalytic degradation. Ag/AgCl nanoparticles were biochemically prepared with metabolin of living fungi which was used as reductant and characterized by X-Ray diffraction (XRD), UV-visible spectroscopy and transmission electro...

  19. High-Reliability Low-Ag-Content Sn-Ag-Cu Solder Joints for Electronics Applications

    Science.gov (United States)

    Shnawah, Dhafer Abdulameer; Said, Suhana Binti Mohd; Sabri, Mohd Faizul Mohd; Badruddin, Irfan Anjum; Che, Fa Xing

    2012-09-01

    Sn-Ag-Cu (SAC) alloy is currently recognized as the standard lead-free solder alloy for packaging of interconnects in the electronics industry, and high- Ag-content SAC alloys are the most popular choice. However, this choice has been encumbered by the fragility of the solder joints that has been observed in drop testing as well as the high cost of the Ag itself. Therefore, low-Ag-content SAC alloy was considered as a solution for both issues. However, this approach may compromise the thermal-cycling performance of the solders. Therefore, to enhance the thermal-cycling reliability of low-Ag-content SAC alloys without sacrificing their drop-impact performance, alloying elements such as Mn, Ce, Ti, Bi, In, Sb, Ni, Zn, Al, Fe, and Co were selected as additions to these alloys. However, research reports related to these modified SAC alloys are limited. To address this paucity, the present study reviews the effect of these minor alloying elements on the solder joint reliability of low-Ag-content SAC alloys in terms of thermal cycling and drop impact. Addition of Mn, Ce, Bi, and Ni to low-Ag-content SAC solder effectively improves the thermal-cycling reliability of joints without sacrificing the drop-impact performance. Taking into consideration the improvement in the bulk alloy microstructure and mechanical properties, wetting properties, and growth suppression of the interface intermetallic compound (IMC) layers, addition of Ti, In, Sb, Zn, Al, Fe, and Co to low-Ag-content SAC solder has the potential to improve the thermal-cycling reliability of joints without sacrificing the drop-impact performance. Consequently, further investigations of both thermal-cycling and drop reliability of these modified solder joints must be carried out in future work.

  20. Electron beam induced evolution in Au, Ag, and interfaced heterogeneous Au/Ag nanoparticles.

    Science.gov (United States)

    Liu, Yuzi; Sun, Yugang

    2015-08-28

    A sintering process of nanoparticles made of Ag, Au, and interfaced Ag/Au heterodimers was investigated by in situ transmission electron microscopy at room temperature. Such a process is driven by the illumination of a high-energy electron beam accelerated at 200 kV that promotes atom diffusion in the nanoparticles that are in physical contact. Upon electron illumination, adjacent Au nanoparticles gradually merge together to form a larger particle along with the reduction of the surface area despite the fact that orientated attachment is not observed. According to the detailed analysis of the size change of the particles and the contact area, it was found that the nanoparticle fusion process is significantly different from the well-established thermal diffusion mechanism. In addition to the similar fusion process of Au nanoparticles, Ag nanoparticles undergo apparent sublimation induced by knock on damage because the transferred energy from the electron beam to nanoparticles is higher than the surface binding energy of Ag atoms when the electron scattering angle is larger than 112°. The particles with a smaller size diffuse faster. Surface diffusion dominates at the beginning of the fusion process followed by slower lattice diffusion. Electron beam illumination can transform the interfaced Au/Ag dimers to Au@Ag core-shell particles followed by a slow removal of the Ag shells. This process under normal electron beam illumination is a lot faster than the thermally driven process. Both diffusion and sublimation of Ag atoms are dependent on the intensity of the electron beam, i.e., a higher beam intensity is favorable to accelerate both the processes.

  1. Surface-enhanced Raman scattering from AgNP-graphene-AgNP sandwiched nanostructures

    Science.gov (United States)

    Wu, Jian; Xu, Yijun; Xu, Pengyu; Pan, Zhenghui; Chen, Sheng; Shen, Qishen; Zhan, Li; Zhang, Yuegang; Ni, Weihai

    2015-10-01

    We developed a facile approach toward hybrid AgNP-graphene-AgNP sandwiched structures using self-organized monolayered AgNPs from wet chemical synthesis for the optimized enhancement of the Raman response of monolayer graphene. We demonstrate that the Raman scattering of graphene can be enhanced 530 fold in the hybrid structure. The Raman enhancement is sensitively dependent on the hybrid structure, incident angle, and excitation wavelength. A systematic simulation is performed, which well explains the enhancement mechanism. Our study indicates that the enhancement resulted from the plasmonic coupling between the AgNPs on the opposite sides of graphene. Our approach towards ideal substrates offers great potential to produce a ``hot surface'' for enhancing the Raman response of two-dimensional materials.We developed a facile approach toward hybrid AgNP-graphene-AgNP sandwiched structures using self-organized monolayered AgNPs from wet chemical synthesis for the optimized enhancement of the Raman response of monolayer graphene. We demonstrate that the Raman scattering of graphene can be enhanced 530 fold in the hybrid structure. The Raman enhancement is sensitively dependent on the hybrid structure, incident angle, and excitation wavelength. A systematic simulation is performed, which well explains the enhancement mechanism. Our study indicates that the enhancement resulted from the plasmonic coupling between the AgNPs on the opposite sides of graphene. Our approach towards ideal substrates offers great potential to produce a ``hot surface'' for enhancing the Raman response of two-dimensional materials. Electronic supplementary information (ESI) available: Additional SEM images, electric field enhancement profiles, Raman scattering spectra, and structure-dependent peak ratios. See DOI: 10.1039/c5nr04500b

  2. Ag/AgCl Loaded Bi2WO6 Composite: A Plasmonic Z-Scheme Visible Light-Responsive Photocatalyst

    Directory of Open Access Journals (Sweden)

    Xiangchao Meng

    2016-01-01

    Full Text Available Hierarchical flower-like Bi2WO6 was successfully synthesized by facile hydrothermal method at low pH. And Ag/AgCl was loaded by photoreduction on its surface. As-prepared photocatalysts were characterized by various techniques. Bi2WO6 was successfully synthesized at a size of 2-3 μm. Depositing Ag/AgCl did not destroy the crystal structure, and both Ag+ and metallic Ag0 were found. The band gap of the composite was 2.57 eV, which indicates that visible light could be the activating irradiation. In the photocatalytic activity test, the composite with 10 wt% Ag/AgCl boasted the highest removal efficiency (almost 100% in 45 min. The significant enhancement can be attributed to the surface plasmon resonance (SPR effect and the establishment of heterostructures between Ag/AgCl and Bi2WO6. A possible mechanism of photocatalytic oxidation in the presence of Ag/AgCl-Bi2WO6 was proposed. This work sheds light on the potential applications of plasmonic metals in photocatalysis to enhance their activities.

  3. Hexagonally arranged arrays of urchin-like Ag hemispheres decorated with Ag nanoparticles for surface-enhanced Raman scattering substrates

    Institute of Scientific and Technical Information of China (English)

    Haibin Tang[1; Guowen Meng[1,2; Zhongbo Li[1; Chuhong Zhu[1; Zhulin Huang[1; Zhaoming Wang[1; Fadi Li[1

    2015-01-01

    The surface topography of noble metal particles is a significant factor in tailoring surface-enhanced Raman scattering (SERS) properties. Here, we present a simple fabrication route to hexagonally arranged arrays of surface-roughened urchin- like Ag hemispheres (Ag-HSs) decorated with Ag nanoparticles (Ag-NPs) for highly active and reproducible SERS substrates. The urchin-like Ag-HS arrays are achieved by sputtering Ag onto the top surface of a highly ordered porous anodic aluminum oxide (AAO) template to form ordered arrays of smooth Ag-HSs and then by electrodepositing Ag-NPs onto the surface of each Ag-HS. Owing to the ordered arrangement of the Ag-HSs and the improved surface roughness, the urchin-like hierarchical Ag-HS arrays can provide sufficient and uniform "hot spots" for reproducible and highly active SERS effects. Using the urchin-like Ag-HS arrays as SERS substrates, 10-7 M dibutyl phthalate (a member of plasticizers family) and 1.5 × 10-5 M PCB-77 (one congener of polychlorinated biphenyl, a notorious class of pollutants) are identified, showing promising potential for these substrates in the rapid recognition of organic pollutants.

  4. Biochemical Synthesis of Ag/AgCl Nanoparticles for Visible-Light-Driven Photocatalytic Removal of Colored Dyes

    Directory of Open Access Journals (Sweden)

    Xiyun Zhao

    2015-04-01

    Full Text Available Photocatalytic removal of organic pollution such as waste colored dyes was a promising technique for environment technique. However, effective photocatalysts were needed to enhance the photocatalytic efficiency. Ag/AgCl was regarded as high performance catalyst for photocatalytic degradation. Ag/AgCl nanoparticles were biochemically prepared with metabolin of living fungi which was used as reductant and characterized by X-Ray diffraction (XRD, UV-visible spectroscopy and transmission electron microscopy (TEM. The Ag/AgCl nanoparticle composites showed spherical aggregation shape with an average size of about 3–5 nm which is well inside the quantum regime. The UV-visible study showed that Ag/AgCl nanoparticles had strong visible light absorption and exhibited excellent visible-light-driven photocatalytic performance. Photocatalytic results indicated that the obtained Ag/AgCl nanoparticles were suitable for photocatalytic removal of RhB dye under visible light irradiation. The excellent photocatalytic activities could be attributed to the quantum size nanoparticles and the Plasmon resonance of Ag/AgCl composites.

  5. New insight into daylight photocatalysis of AgBr@Ag: synergistic effect between semiconductor photocatalysis and plasmonic photocatalysis.

    Science.gov (United States)

    Jiang, Jing; Li, Hao; Zhang, Lizhi

    2012-05-14

    Noble metal nanoparticles (NPs) are often used as electron scavengers in conventional semiconductor photocatalysis to suppress electron-hole (e(-)-h(+) ) recombination and promote interfacial charge transfer, and thus enhance photocatalytic activity of semiconductors. In this contribution, it is demonstrated that noble metal NPs such as Ag NPs function as visible-light harvesting and electron-generating centers during the daylight photocatalysis of AgBr@Ag. Novel Ag plasmonic photocatalysis could cooperate with the conventional AgBr semiconductor photocatalysis to enhance the overall daylight activity of AgBr@Ag greatly because of an interesting synergistic effect. After a systematic investigation of the daylight photocatalysis mechanism of AgBr@Ag, the synergistic effect was attributed to surface plasmon resonance induced local electric field enhancement on Ag, which can accelerate the generation of e(-)-h(+) pairs in AgBr, so that more electrons are produced in the conduction band of AgBr under daylight irradiation. This study provides new insight into the photocatalytic mechanism of noble metal/semiconductor systems as well as the design and fabrication of novel plasmonic photocatalysts.

  6. Detection of HBsAg, HBcAg, and HBV DNA in ovarian tissues from patients with HBV infection

    Institute of Scientific and Technical Information of China (English)

    Li-Zhang Chen; Xue-Gong Fan; Jian-Ming Gao

    2005-01-01

    AIM: To investigate the presence of HBsAg, HBcAg, and HBV DNA in ovarian tissues from patients with HBV infection.METHODS: HBsAg and HBcAg were examined in ovarian biopsy tissues from 26 patients with HBV infection by immunocytochemistry, and HBV DNA was detected in ovarian tissues by PCR.RESULTS: HBsAg and HBcAg were present with the same positive rate of 34.6% (9/26). The total positive rate was 46.2% (12/26). HBsAg and HBcAg were positive in 6 (23.1%) of the 26 patients. Brown positive particles were diffusely distributed in ovarian cells. The positive rate of HBV DNA was 58.3% (7/12).CONCLUSION: HBsAg, HBcAg, and HBV DNA can be detected in ovarian tissues from patients with HBV infection. The presence of HBsAg and HBcAg in ovarian tissues does not correlate with the HBV markers in serum.

  7. A dry method to synthesize dendritic Ag2Se nanostructures utilizing CdSe quantum dots and Ag thin films

    Science.gov (United States)

    Hu, Lian; Zhang, Bingpo; Xu, Tianning; Li, Ruifeng; Wu, Huizhen

    2015-01-01

    Dendritic Ag2Se nanostructures are synthesized in a dry environment by UV irradiating the hybrids composed of CdSe quantum dots (QDs) and silver (Ag). UV irradiation on CdSe QDs induces a photooxidation effect on the QD surface and leads to the formation of SeO2 components. Then SeO2 reacts with the Ag atoms in either Ag film or QD layer to produce the Ag2Se. The growth mechanism of Ag2Se dendrites on solid Ag films is explored and explained by a diffusion limited aggregation model in which the QD layer provides enough freedom for Ag2Se motion. Since the oxidation of the CdSe QDs is the critical step for the Ag2Se dendrites formation this dry chemical interaction between QDs and Ag film can be applied in the study of the QD surface chemical properties. With this dry synthesis method, the Ag2Se dendrites can also be facilely formed at the designed area on Ag substrates.

  8. A comparative study about electronic structures at rubrene/Ag and Ag/rubrene interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Sumona, E-mail: sumona.net.09@gmail.com; Mukherjee, M. [Saha Institute of Nuclear Physics, 1/AF, Bidhan Nagar, Kolkata 700064 (India)

    2015-10-15

    The contact between the electrode and the organic semiconductor is one of the most crucial factors in determining the organic device performance. The development and production technology of different organic devices require the understanding of different types of metal/organic semiconducting thin film interfaces. Comparisons about the electronic structures at Rubrene/Ag and Ag/Rubrene interfaces have been studied using photoemission spectroscopy. The Ag on rubrene interfaces is found to show more interesting and complex natures than its counterpart. The vacuum level (VL) was shifted about 0.51 eV from push back effect for deposition of 5 Å rubrene onto Ag film whereas the electronic features of silver was only suppressed and no energy shift was resulted. While the deposition of 5 Å Ag onto rubrene film leads to the diffusion of the Ag atoms, as a cluster with quantum size effect, inside the film. Angle dependent XPS measurement indicates that diffused metal clusters were present at entire probed depth of the film. Moreover these clusters dope the uppermost surface of the rubrene film which consequences a shift of the electronic states of thick organic film towards higher binding energy. The VL was found to shift about 0.31 eV toward higher binding energy whereas the shift was around 0.21 eV for the electronic states of rubrene layer.

  9. AKTIVITAS ANTIBAKTERI KAIN KASA TERLAPISI TiO¬2/Ag AMORF, Ag, DAN KITOSAN/Ag TERHADAP BAKTERI GRAM NEGATIF DAN POSITIF (The Antibacterial Activity of Gauze Coated by Tio¬2/Ag Amorphous, Ag, and Chitosan/Ag Against Gram Negative and Positive Bacteria)

    OpenAIRE

    Purnawan, Candra; Martini, Tri; Rawiningtyas, Sotya; Zidny, Zidny Z.S.R.A.

    2014-01-01

    ABSTRAKPelapisan kain kasa dengan komposit TiO2/Ag amorf, kitosan/Ag, dan Ag telah dilakukan menggunakan metode dip coating dengan variasi urutan pelapisan. Komposit TiO2/Ag amorf disintesis dengan metode sol gel dalam pelarut etanol. Hasil sintesis dikarakterisasi menggunakan FTIR dan XRD. Kain kasa hasil pelapisan dikarakterisasi menggunakan XRD dan dilakukan uji antibakteri menggunakan metode optical density pada λ 600nm terhadap aktivitas bakteri Eschericia coli dan Stapylococcus aureus. ...

  10. The strange diffusivity of Ag atoms in CdTe

    CERN Document Server

    Wolf, H; Ostheimer, V; Schachtrup, A R; Stolwijk, N A; Wichert, T

    2001-01-01

    The diffusion of Ag atoms in CdTe was investigated using the radiotracer $^{111}\\!$Ag, which was introduced by implantation with an energy of 60 or 80 keV. The measured diffusion profiles are explained by assuming the existence of a repulsive interaction between Ag and residual Cu atoms causing a drift of the Ag atoms towards the centre of the crystal, which supposes the diffusion in a concentration gradient. This effect vanishes if the Ag concentration is increased and becomes more pronounced if the crystals are simultaneously co- doped with Cu. (11 refs).

  11. Thickness-dependent spontaneous dewetting morphology of ultrathin Ag films.

    Science.gov (United States)

    Krishna, H; Sachan, R; Strader, J; Favazza, C; Khenner, M; Kalyanaraman, R

    2010-04-16

    We show here that the morphological pathway of spontaneous dewetting of ultrathin Ag films on SiO2 under nanosecond laser melting is dependent on film thickness. For films with thickness h of 2 nm intermolecular forces, we have estimated the morphological transition thickness for the intermolecular forces for Ag on SiO2. The theory predictions agree well with observations for Ag. These results show that it is possible to form a variety of complex Ag nanomorphologies in a consistent manner, which could be useful in optical applications of Ag surfaces, such as in surface enhanced Raman sensing.

  12. Microstructure evolution during 300 °C storage of sintered Ag nanoparticles on Ag and Au substrates

    Energy Technology Data Exchange (ETDEWEB)

    Paknejad, S.A. [King’s College London, Physics Department, Strand, London WC2R 2LS (United Kingdom); Dumas, G. [Eltek Semiconductors Ltd, Nelson Road Industrial Estate, Dartmouth, Devon TQ6 9LA (United Kingdom); West, G. [Loughborough University, Materials Department, Loughborough LE11 3TU (United Kingdom); Lewis, G. [Eltek Semiconductors Ltd, Nelson Road Industrial Estate, Dartmouth, Devon TQ6 9LA (United Kingdom); Mannan, S.H., E-mail: samjid.mannan@kcl.ac.uk [King’s College London, Physics Department, Strand, London WC2R 2LS (United Kingdom)

    2014-12-25

    Highlights: • Shear strength of pressure-free sintered Ag found to increase during ageing at 300 °C on Ag substrate. • Rapid collapse of void number density after 24 h ageing in the sintered Ag layer. • Higher porosity at edge of joint compared to the middle. • Shear strength of pressure-free sintered Ag decreases during ageing at 300 °C due to high porosity layer growth. • Void free layer and high porosity layer growth explained in terms of atomic diffusion and grain boundary migration. - Abstract: A silver nanoparticle based die attach material was used in a pressure free process to bond 2.5 mm square Ag plated Si die to Ag and Au plated substrates. The assemblies were stored at 300 °C for up to 500 h and the morphology of the sintered Ag and the shear strength were monitored as a function of time. On Ag substrate it was found that die shear strength increased and that the Ag grains grew in size and porosity decreased over time. There was also a clear difference in morphology between sintered Ag at the die edge and centre. On Au substrate, it was observed that the initially high die shear strength decreased with storage time and that voids migrated away from the Ag/Au interface and into the Ag joint. This has led to the formation of a void free layer at the interface followed by a high porosity region, which weakened the joint. The microstructure reveals a high density of grain and twin boundaries which facilitate the Ag and Au atomic diffusion responsible. The grain structure of the plated Au led to diffusion of Au into the Ag via high-angle tilt grain boundaries, and grain boundary migration further dispersed the Au into the Ag layer.

  13. Biotic and abiotic interactions in aquatic microcosms determine fate and toxicity of Ag nanoparticles: part 2-toxicity and Ag speciation.

    Science.gov (United States)

    Bone, Audrey J; Colman, Benjamin P; Gondikas, Andreas P; Newton, Kim M; Harrold, Katherine H; Cory, Rose M; Unrine, Jason M; Klaine, Stephen J; Matson, Cole W; Di Giulio, Richard T

    2012-07-03

    To study the effects of complex environmental media on silver nanoparticle (AgNP) toxicity, AgNPs were added to microcosms with freshwater sediments and two species of aquatic plants (Potamogeton diversifolius and Egeria densa), followed by toxicity testing with microcosm surface water. Microcosms were designed with four environmental matrices in order to determine the contribution of each environmental compartment to changes in toxicity: water only (W), water + sediment (WS), water + plants (WP), and water + plants + sediment (WPS). Silver treatments included AgNPs with two different coatings, gum arabic (GA-AgNPs) or polyvinylpyrollidone (PVP-AgNPs), as well as AgNO(3). Water samples taken from the microcosms at 24 h postdosing were used in acute toxicity tests with two standard model organisms, early life stage zebrafish (Danio rerio) and Daphnia magna. Speciation of Ag in these samples was analyzed using Ag L3-edge X-ray absorption near edge spectroscopy (XANES). Silver speciation patterns for the nanoparticle treatments varied significantly by coating type. While PVP-AgNPs were quite stable and resisted transformation across all matrices (>92.4% Ag(0)), GA-AgNP speciation patterns suggest significantly higher transformation rates, especially in treatments with plants (Ag(0) in WP and WPS, respectively) and moderately increased transformation with sediments (Ag(0)). Additionally, the presence of plants in the microcosms (with and without sediments) reduced both the concentration of Ag in the water column and toxicity for all Ag treatments. Reductions in toxicity may have been related to decreased water column concentrations as well as changes in the surface chemistry of the particles induced by organic substances released from the plants.

  14. An Efficient Ag+ Ionophore Based on Thiacalix[4]arene

    Institute of Scientific and Technical Information of China (English)

    LI Xiong; GONG Shu-Ling; YANG Wei-Ping; CHEN Yuan-Yin

    2008-01-01

    A novel Ag+ ionophore, p-tert-butyi-tetrakis(hydrazinocarbonylmethoxy)thiacalix[4]arene in 1,3-alternate conformation (thiacalix[4]arene tetrahydrazide, 1) was synthesized. Its binding properties towards alkali and transition metal cations were studied by noncompetitive liquid-liquid extraction of alkali metal (Li+, Na+, K+ and Cs+)and transition metal (Co2+, Ni2+, Cu2+, Zn2+, Ag+) picrates. It was found that the thiacalix[4]arene tetrahydrazide exhibited high extractability towards Ag+, lower percent extraction towards Cu2+, and little or no extraction ability towards the others. The selectivity towards Ag+ was further evaluated by competitive Ag+ extraction experiments in the mixture of the above-mentioned nine cations, the concentration of which was monitored with ICP-OES. 1HNMR titration experiments and ESI-MS proved the stoichiometry of 1 to Ag+ was 1 : 1, and the 'N-Ag+' interaction with the assistance of thiacalixarene skeleton was primarily involved in the complexation.

  15. Ag3Sn plate formation in the solidification of near-ternary eutectic Sn-Ag-Cu

    Science.gov (United States)

    Kang, Sung K.; Shih, Da-Yuan; Donald, Ny.; Henderson, W.; Gosselin, Timothy; Sarkhel, Amit; Charles Goldsmith, Ny.; Puttlitz, Karl J.; Choi, Won Kyoung

    2003-06-01

    Near-ternary eutectic Sn-Ag-Cu alloys are leading lead-free candidate solders for various applications. These alloys yield three phases upon solidification: β-Sn,Ag3Sn, and Cu6Sn5. Large, plate-like, pro-eutectic Ag3Sn structures can grow rapidly within the liquid phase, potentially adversely affecting the mechanical behavior and reducing the fatigue life of solder joints. This article reports on the formation of such plates in Sn-Ag-Cu solder balls and joints and demonstrates how large Ag3Sn plate formation can be minimized.

  16. Shell Thickness-Dependent Strain Distributions of Confined Au/Ag and Ag/Au Core-Shell Nanoparticles

    OpenAIRE

    Feng Liu; Honghua Huang; Ying Zhang; Ting Yu; Cailei Yuan; Shuangli Ye

    2015-01-01

    The shell thickness-dependent strain distributions of the Au/Ag and Ag/Au core-shell nanoparticles embedded in Al2O3 matrix have been investigated by finite element method (FEM) calculations, respectively. The simulation results clearly indicate that there is a substantial strain applied on both the Au/Ag and Ag/Au core-shell nanoparticles by the Al2O3 matrix. For the Au/Ag nanoparticles, it can be found that the compressive strain existing in the shell is stronger than that on the center of ...

  17. Mechanical and electrical properties of In-Bi solder at Bi2212 superconductor interface with annealed Ag spray layers and Ag precoating layers

    Institute of Scientific and Technical Information of China (English)

    Seung-Yong SHIN; Ji-Hyun LEE; Hai-Woong PARK

    2009-01-01

    The electrical properties of solder contact layers between Cu-Ni shunt metal and tube type Bi2212 superconductor that is applied in superconducting fault current limiter were studied. The contact properties of the solders are improved not only by Ag precoating layers, but also by the pre-sprayed Ag layer and subsequent Ag precoating layers. The annealed Ag sprayed layers onto Bi2212 superconductor prior to Ag electroplating work as protecting layers for the superconductor from plating solutions. The contact angle of the electroplated Ag layer is 42.91- and decreases to 15.25- and 5.88- with Ag sprayed layer and additional Ag electroplated layers. The Ag sprayed layer with suitable annealing prior to Ag electroplating improves contact strength of the Ag electroplated layer by about 12% due to denser microstructure of the Ag electroplated layers.

  18. Sequestration of Ag(I) from aqueous solution as Ag(0) nanostructures by nanoscale zero valent iron (nZVI)

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yalei, E-mail: zhangyalei2003@163.com [Tongji University, State Key Laboratory of Pollution Control and Resources Reuse (China); Yan, Jing [Tongji University, Modern Agricultural Science and Engineering Institute (China); Dai, Chaomeng, E-mail: daichaomeng@163.com, E-mail: daichaomeng@tongji.edu.cn [Tongji University, College of Civil Engineering (China); Li, Yuting; Zhu, Yan [Tongji University, Modern Agricultural Science and Engineering Institute (China); Zhou, Xuefei [Tongji University, State Key Laboratory of Pollution Control and Resources Reuse (China)

    2015-11-15

    This study investigates the application of nanoparticle zero valent iron (nZVI) to sequester Ag(I) as Ag(0) nanostructures from aqueous solution. Batch experiments were performed with nZVI exposed to aqueous Ag(I) to investigate the effects of environmental parameters, including nZVI dose, temperature and pH. High temperature facilitates Ag(I) sequestration, and the rate constants are determined to be 0.02, 0.12, and 0.31 mg L/m{sup 2} at 30, 50, and 60 °C, respectively. Ag(I) sequestration was adversely affected by adding nitric acid to the solution due to significant acid washing, decreasing the available nZVI active sites. Characterization techniques including TEM, XRD, and HR-XPS revealed that nZVI is oxidized to lepidocrocite and magnetite/maghemite and confirmed the formation of nanocrystalline silver. HR-XPS analysis indicated that Ag{sub 2}O forms rapidly as an intermediate due to Ag(I) adsorption onto the FeOOH layer. The Ag(0) nanostructures that are formed are fractal, spherical, and dendritic or rod-like, respectively, in morphology by FE-TEM images at different Ag/Fe mass ratios. A general reaction model for the interaction Ag(I) with nZVI is proposed. Our results suggest that nZVI is effective for Ag(I) removal.

  19. New frontiers in water purification: highly stable amphopolycarboxyglycinate-stabilized Ag-AgCl nanocomposite and its newly discovered potential

    Science.gov (United States)

    Krutyakov, Yurii A.; Zherebin, Pavel M.; Kudrinskiy, Alexey A.; Zubavichus, Yan V.; Presniakov, Mikhail Yu; Yapryntsev, Alexey D.; Karabtseva, Anastasia V.; Mikhaylov, Dmitry M.; Lisichkin, Georgii V.

    2016-09-01

    A simple synthetic procedure for high-stable dispersions of porous composite Ag/AgCl nanoparticles stabilized with amphoteric surfactant sodium tallow amphopolycarboxyglycinate has been proposed for the first time. The prepared samples were characterized by UV-vis spectroscopy, x-ray powder diffraction (XRD), x-ray photoelectron spectroscopy, small area electron diffraction (SAED), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and electron probe micro-analysis. In addition, measurements (carried out at the Kurchatov synchrotron radiation source stations) of the Ag K-edge extended x-ray absorption fine structure (EXAFS) and x-ray absorption near edge structure (XANES) spectra and XRD of the prepared nanoparticles have been performed. The obtained results suggest that small-sized Ag clusters are homogeneously distributed in the mass of the AgCl nanoparticle (~80 nm) formed during the synthesis. The Ag/AgCl dispersion demonstrates photocatalytic activity (with respect to methyl orange) and high bactericidal activity against E. coli. This activity is superior to the activity of both Ag and AgCl nanoparticles stabilized by the same surfactant. Thus, porous composite Ag/AgCl nanoparticles can be used as a multifunctional agent that is able to remove both pollutants and bacterium from water.

  20. Size-dependent transformation from Ag templates to Au-Ag nanoshells via galvanic replacement reaction in organic medium

    Energy Technology Data Exchange (ETDEWEB)

    Karvianto; Chow, G. M., E-mail: msecgm@nus.edu.sg [National University of Singapore, Department of Materials Science and Engineering (Singapore)

    2012-10-15

    The transformation from Ag templates to Au-Ag nanoshells via galvanic replacement reaction with HAuCl{sub 4} was systematically studied in an organic medium in the presence of oleylamine. Decahedral ({approx}43 nm in size) and triangular prism ({approx}53 nm in edge length) Ag templates transformed into equiaxed and triangular prismatic Au-Ag nanoshells, respectively. The first step involved structural and morphological changes from Ag templates to Au-Ag nanoshells with an interior cavity. In the second step, the growth of the shells continued through the deposition of Au. The shell thickness increased from {approx}5 to {approx}10 nm for the equiaxed Au-Ag nanoshells ({approx}39-nm interior cavity) and {approx}5 to {approx}8 nm for the triangular prismatic Au-Ag nanoshells ({approx}52-nm interior edge length). Oleylamine not only served as a surfactant but also removed AgCl precipitates and reduced HAuCl{sub 4}. For the nanoshells derived from the {approx}20-nm Ag decahedrons, further reaction in excess HAuCl{sub 4} collapsed the nanoshells into Au-rich solid fragments. However, the nanoshells derived from the {approx}43-nm Ag decahedrons, the nanoshell structure not only persisted in excess HAuCl{sub 4}, but its shell thickness also increased. The size-dependent transformation of these nanoshells is discussed.

  1. An EBIS-based heavy ion injector for the AGS

    Energy Technology Data Exchange (ETDEWEB)

    Kponou, A.; Alessi, J.; Beebe, E.; Brennan, J.M.; Hershcovitch, A.; Prelec, K.; Raparia, D.

    1994-09-01

    An electron beam ion source (EBIS), followed by a heavy ion RFQ and superconducting linac, can be considered as a heavy ion injector for high energy accelerators, such as the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. A test EBIS, on long term loan from Sandia National Laboratory, is presently being commissioned at BNL. Experiments on this source will be used in evaluating the parameters for an EBIS-based RHIC injector. Some results of this commissioning, as well as the conceptual designs of the RFQ and linac, are presented.

  2. Mechanisms of Toxicity of Ag Nanoparticles in Comparison to Bulk and Ionic Ag on Mussel Hemocytes and Gill Cells.

    Science.gov (United States)

    Katsumiti, Alberto; Gilliland, Douglas; Arostegui, Inmaculada; Cajaraville, Miren P

    2015-01-01

    Silver nanoparticles (Ag NPs) are increasingly used in many products and are expected to end up in the aquatic environment. Mussels have been proposed as marine model species to evaluate NP toxicity in vitro. The objective of this work was to assess the mechanisms of toxicity of Ag NPs on mussel hemocytes and gill cells, in comparison to ionic and bulk Ag. Firstly, cytotoxicity of commercial and maltose stabilized Ag NPs was screened in parallel with the ionic and bulk forms at a wide range of concentrations in isolated mussel cells using cell viability assays. Toxicity of maltose alone was also tested. LC50 values were calculated and the most toxic Ag NPs tested were selected for a second step where sublethal concentrations of each Ag form were tested using a wide array of mechanistic tests in both cell types. Maltose-stabilized Ag NPs showed size-dependent cytotoxicity, smaller (20 nm) NPs being more toxic than larger (40 and 100 nm) NPs. Maltose alone provoked minor effects on cell viability. Ionic Ag was the most cytotoxic Ag form tested whereas bulk Ag showed similar cytotoxicity to the commercial Ag NPs. Main mechanisms of action of Ag NPs involved oxidative stress and genotoxicity in the two cell types, activation of lysosomal AcP activity, disruption of actin cytoskeleton and stimulation of phagocytosis in hemocytes and increase of MXR transport activity and inhibition of Na-K-ATPase in gill cells. Similar effects were observed after exposure to ionic and bulk Ag in the two cell types, although generally effects were more marked for the ionic form. In conclusion, results suggest that most observed responses were due at least in part to dissolved Ag.

  3. The Y-Ag-Al system

    Energy Technology Data Exchange (ETDEWEB)

    Gumenyuk, T.M.; Kuz' ma, Yu.B.; Stel' makhovych, B.M. [L' vov State Univ. (Ukraine). Dept. of Anal. Chem.

    2000-03-14

    The interaction between the components in the Y-Ag-Al system at 870 K has been studied using X-ray analysis. The phase diagram in the region up to 50 at.% of yttrium has been constructed. The limits of the solid solution regions of the binary compounds and the homogeneity ranges of the ternary ones have been determined. The crystal structures of the ternary aluminides Y{sub 3}Ag{sub 2}Al{sub 7} (Ca{sub 3}Cu{sub 2}Al--type structure, space group R anti 3m, a=0.55422(2), c=2.6259(1) nm) and YAg{sub 0.6}Al{sub 1.4} (KHg{sub 2}-type structure, space group Imma, a=0.45399(2), b=0.71551(3), c=0.78712(4) nm) have been studied for the first time. (orig.)

  4. Enhanced Visible Light Photocatalytic Degradation of Organic Pollutants over Flower-Like Bi2O2CO3 Dotted with Ag@AgBr

    Directory of Open Access Journals (Sweden)

    Shuanglong Lin

    2016-10-01

    Full Text Available A facile and feasible oil-in-water self-assembly approach was developed to synthesize flower-like Ag@AgBr/Bi2O2CO3 micro-composites. The photocatalytic activities of the samples were evaluated through methylene blue degradation under visible light irradiation. Compared to Bi2O2CO3, flower-like Ag@AgBr/Bi2O2CO3 micro-composites show enhanced photocatalytic activities. In addition, results indicate that both the physicochemical properties and associated photocatalytic activities of Ag@AgBr/Bi2O2CO3 composites are shown to be dependent on the loading quantity of Ag@AgBr. The highest photocatalytic performance was achieved at 7 wt % Ag@AgBr, degrading 95.18% methylene blue (MB after 20 min of irradiation, which is over 1.52 and 3.56 times more efficient than that of pure Ag@AgBr and pure Bi2O2CO3, respectively. Bisphenol A (BPA was also degraded to further demonstrate the degradation ability of Ag@AgBr/Bi2O2CO3. A photocatalytic mechanism for the degradation of organic compounds over Ag@AgBr/Bi2O2CO3 was proposed. Results from this study illustrate an entirely new approach to fabricate semiconductor composites containing Ag@AgX/bismuth (X = a halogen.

  5. Effect of Nanoscale Ag Film Thickness on the Electrical and Optical Properties of Transparent IZTO/Ag/IZTO Multilayer Films Deposited on Glass Substrates.

    Science.gov (United States)

    Oh, Dohyun; Lee, Nam Hyun; Cho, Woon-Jo; Kim, Tae Whan

    2015-07-01

    The effect of nanoscale Ag film thickness on the electrical and optical properties in transparent conducting oxide films consisting of an IZTO/Ag/IZTO multilayer were investigated. The homoge- neous morphologies of the Ag films sandwiched between the IZTO films affected the optical and electrical properties of the IZTO/Ag/IZTO multilayer films. The transmittance and resistivity of the IZTO/Ag/IZTO multilayer films decreased with increasing Ag film thickness. The resistivities of the IZTO/Ag/IZTO multilayer films grown on glass substrates were decreased by using an Ag thin inter- layer in comparison with that of the IZTO single layer.

  6. Orientation of nickelocene on Ag(100)

    Science.gov (United States)

    Pugmire, D. L.; Woodbridge, C. M.; Langell, M. A.

    1998-08-01

    High-resolution electron-energy-loss spectroscopy has been used to study the molecular adsorption of nickelocene, Ni(C 5H 5) 2, on Ag(100). Results indicate that at up to one monolayer coverage, nickelocene adsorbs molecularly with its axis approximately perpendicular to the surface. At very high coverages, the molecular axis is not exclusively oriented along the surface normal. This is possibly due to randomization of the metallocene orientation as multilayers are formed.

  7. Results from the AGS Booster transverse damper

    Energy Technology Data Exchange (ETDEWEB)

    Russo, D.; Brennan, M.; Meth, M.; Roser, T.

    1993-01-01

    To reach the design intensity of 1.5 [times] 10[sup 13] protons per pulse in the AGS Booster, transverse coupled bunch instabilities with an estimated growth rate of 1500s[sup [minus]1] have to be dampened. A prototype transverse damper has been tested successfully using a one turn digital delay and closed orbit suppression implemented in a programmable gate array. An updated damper, which includes an algorithm to optimize damping for a changing betatron rune, will also be presented.

  8. Results from the AGS Booster transverse damper

    Energy Technology Data Exchange (ETDEWEB)

    Russo, D.; Brennan, M.; Meth, M.; Roser, T.

    1993-06-01

    To reach the design intensity of 1.5 {times} 10{sup 13} protons per pulse in the AGS Booster, transverse coupled bunch instabilities with an estimated growth rate of 1500s{sup {minus}1} have to be dampened. A prototype transverse damper has been tested successfully using a one turn digital delay and closed orbit suppression implemented in a programmable gate array. An updated damper, which includes an algorithm to optimize damping for a changing betatron rune, will also be presented.

  9. Identification of Ag and Cd photoluminescence in $^{111}$Ag-doped GaN

    CERN Document Server

    Stötzler, A; Deicher, M

    1999-01-01

    In order to unambiguously identify the chemical nature of Cd and Ag related optical transitions in GaN, epitaxial GaN layers were implanted with the radioactive isotope $^{111}$Ag which decays into stable $^{111}$Cd. This chemical transmutation was monitored by photoluminescence (PL) spectroscopy. Being an element specific property, the half-life of this decay was used to establish the chemical assignment of the optical transitions to a specific defect. We found that the Ag related transitions consist of a series of four single lines (1.610, 1.600, 1.594, and 1.573 eV), each accompanied by two phonon replicas separated by 63 meV. Cd produces two PL bands centered at 2.7 and 3.2 eV. Additional Cd-related single transitions at 3.341, 3.328, and 3.249 eV have been observed. Exponential fits to the PL intensities yield half-lives of $t_{1/2}^{Ag}$= (7.61$\\pm$0.27) d and $t_{1/2}^{Cd}$=(7.60$\\pm$0.27) d, respectively, in good agreement with the half-life of $^{111}$Ag of 7.45 d. (13 refs).

  10. Electrochemical detection of aqueous Ag+ based on Ag+-assisted ligation reaction

    Science.gov (United States)

    Miao, Peng; Han, Kun; Wang, Bidou; Luo, Gangyin; Wang, Peng; Chen, Mingli; Tang, Yuguo

    2015-03-01

    In this work, a novel strategy to fabricate a highly sensitive and selective biosensor for the detection of Ag+ is proposed. Two DNA probes are designed and modified on a gold electrode surface by gold-sulfur chemistry and hybridization. In the presence of Ag+, cytosine-Ag+-cytosine composite forms and facilitates the ligation event on the electrode surface, which can block the release of electrochemical signals labeled on one of the two DNA probes during denaturation process. Ag+ can be sensitively detected with the detection limit of 0.1 nM, which is much lower than the toxicity level defined by U.S. Environmental Protection Agency. This biosensor can easily distinguish Ag+ from other interfering ions and the performances in real water samples are also satisfactory. Moreover, the two DNA probes are designed to contain the recognition sequences of a nicking endonuclease, and the ligated DNA can thus be cleaved at the original site. Therefore, the electrode can be regenerated, which allows the biosensor to be reused for additional tests.

  11. The Y-Ag-Ga system

    Energy Technology Data Exchange (ETDEWEB)

    Krachan, T.; Stel' makhovych, B.; Kuz' ma, Yu

    2005-01-11

    The isothermal section at 670 K of the Y-Ag-Ga system in the region of 0-33 at.% Y has been constructed using X-ray diffraction data. The existence of earlier known ternary gallides has been confirmed. Their homogeneity regions, atomic coordinates and distribution of atoms in the structures have been determined: Y{sub 3}Ag{sub 2.55}Ga{sub 8.45} (La{sub 3}Al{sub 11}-type structure, a 0.4310(1) nm, b = 1.2865(3) nm, c = 0.9552(3) nm, R{sub F} = 0.043), YAg{sub 0.22}Ga{sub 1.78} (CaIn{sub 2}-type structure, a = 0.44565(1) nm, c 0.72032(2) nm, R{sub I} = 0.081), YAg{sub 0.74}Ga{sub 1.26} (KHg{sub 2}-type structure, a 0.45302(2) nm, b = 0.70805(3) nm, c = 0.78056(3) nm, R{sub I} = 0.059). The crystal structure of the new ternary compound YAg{sub 1.1}Ga{sub 1.9} ({beta}-YbAgGa{sub 2}-type structure, Pnma, a = 0.69654(3) nm, b = 0.43391(2) nm, c = 1.02126(5) nm, R{sub I} = 0.087) has been studied for the first time.

  12. Multifunction of Ni/Ag Nanocompound Fluid

    Directory of Open Access Journals (Sweden)

    Mu-Jung Kao

    2013-01-01

    Full Text Available An arc-submerged nanoparticle synthesis system (ASNSS is proposed and developed for fabricating Ni/Ag nanocompound fluid. In the development process, the positive and negative electrodes in the system are Ni and Ag, respectively. Applied electrical energy then produces heating source by generating an adequate arc with a high temperature that can melt and vaporize the two electrodes. The nanocompound fluid that is generated by the synthesis system is analyzed by morphological analysis, Zeta potential analysis, heat conductivity analysis, magnetic characteristic analysis, and UV-Vis absorption spectra analysis. Experimental results show that increasing the concentration of added particles and the higher temperature can be helpful to the enhancement of thermal conductivity. The Ni/Ag nanofluid not only preserves the magnetic character of the nickel and the ability of silver to absorb visible light but also enhances the thermal conductivity. The absorption occurs at 406 nm wavelength (redshift from 396 nm to 406 nm, which means that, under the excitement of visible light range (400~700 nm, it can let more easy electrons jump to the conductivity zone from the valence electron zone.

  13. Highly efficient and stable Ag-AgBr/TiO2 composites for destruction of Escherichia coli under visible light irradiation.

    Science.gov (United States)

    Wang, Xiaoping; Lim, Teik-Thye

    2013-08-01

    A series of Ag-AgBr/TiO2 composites were prepared by a sol-gel method followed by photoreduction. Effect of Ag-AgBr content on the physicochemical properties and antibacterial activities of the Ag-AgBr/TiO2 composites was investigated. These composites showed intrinsic antibacterial activities against Escherichia coli (E. coli) in the dark attributed to the Ag nanoparticles dispersed in the composites. Under visible light irradiation, inactivation of E. coli over these Ag-AgBr/TiO2 composites was attributed to both their photocatalytic disinfection activities and intrinsic antibacterial properties. The Ag-AgBr/TiO2 with an optimum Ti/Ag atomic ratio of 10 exhibited superior visible-light photocatalytic activities for ibuprofen degradation and mineralization as compared to the other Ag-AgBr/TiO2 composites and also Ag-AgBr/P25, Ag/TiO2 and TiO2. It is probably because of the coexistence of two visible-light active components (AgBr and Ag nanoparticles) and the most effective separation of photogenerated electrons and holes in this photocatalyst. Correspondingly, the photocatalyst achieved a much higher efficiency of E. coli destruction than Ag-AgBr/P25 and TiO2. E. coli was almost completely inactivated (7-log reduction) within 60 min by the photocatalyst with a rather low dosage of 0.05 g L(-1) under white LED irradiation. Furthermore, the Ag-AgBr/TiO2 showed high stability for photocatalytic destruction of E. coli and the dark repair and photoreactivation did not occur after the photocatalytic process. Finally, the action spectrum of this photocatalyst for E. coli inactivation and the influence of several inorganic ions present in surface water were also investigated.

  14. Electrical and optical investigations in Te–Ge–Ag and Te–Ge–AgI chalcogenide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Cui, S. [Glass and Ceramic Laboratory, Institute of Chemical Sciences of Rennes, UMR-CNRS 6226, University of Rennes 1, 35042 Rennes cedex (France); Department of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou 310027 (China); Le Coq, D., E-mail: david.lecoq@univ-rennes1.fr [Glass and Ceramic Laboratory, Institute of Chemical Sciences of Rennes, UMR-CNRS 6226, University of Rennes 1, 35042 Rennes cedex (France); Boussard-Plédel, C.; Bureau, B. [Glass and Ceramic Laboratory, Institute of Chemical Sciences of Rennes, UMR-CNRS 6226, University of Rennes 1, 35042 Rennes cedex (France)

    2015-08-05

    Highlights: • Evolution of the electrical conductivities in Ag and AgI-GeTe{sub 4} glasses. • We demonstrate a change of a conductivity type (electronic vs ionic) in AgI–GeTe{sub 4} glasses. • A structural model for Ag and AgI–GeTe{sub 4} glasses is proposed. • The role of Ag in the structure of the Ag and AgI–GeTe{sub 4} glasses is described. - Abstract: (GeTe{sub 4}){sub 100−x}Ag{sub x} and (GeTe{sub 4}){sub 100−x}(AgI){sub x} glasses were prepared by a melting-quenching method. The glass electrical conductivity was investigated by both electrochemical impedance spectroscopy at different temperatures from 283 K to 333 K and four-probe method at room temperature (293 K). Meanwhile, as a major factor determining the electrical conductivity of a solid, optical band gap was also studied. By comparing the electrical conductivity values and glass optical band gap evolution, it was found that (GeTe{sub 4}){sub 100−x}Ag{sub x} glasses are mainly electronic conductive. On the other hand, the electrical conductivities of (GeTe{sub 4}){sub 100−x}(AgI){sub x} glasses firstly show a monotonic decrease by increasing AgI up to 15 mol.%, and then an increase when the AgI content is higher than 15 mol.%. The activation energy E{sub a} and the pre-exponential factor σ{sub 0} show apparent turning point when AgI content is 15 mol.%, signifying a conductivity mechanism change. In this paper, correlations between the conductivity and hypothetical structures in (GeTe{sub 4}){sub 100−x}Ag{sub x} and (GeTe{sub 4}){sub 100−x}(AgI){sub x} glasses are done and the importance of the Ag role is underlined.

  15. SPIN TRANSPORT FROM AGS TO RHIC WTIH TWO PARTIAL SNAKES IN AGS.

    Energy Technology Data Exchange (ETDEWEB)

    MACKAY, W.W.; LUCCIO, A.U.; TSOUPAS, N.; TAKANO, J.

    2006-06-23

    The stable spin direction in the RHIC rings is vertical. With one or two partial helical Siberian snakes in the AGS, the stable spin direction at extraction is not vertical. Interleaved vertical and horizontal bends in the transport line between AGS and the RHIC rings also tend to tip the spin away from the vertical. In order to maximize polarization in RHIC, we examined several options to improve the matching of the stable spin direction during beam transfer from the AGS to each of the RHIC rings. While the matching is not perfect, the most economical method appears to be a lowering of the injection energy by one unit of G{gamma} from 46.5 to 45.5.

  16. Heterojunction double dumb-bell Ag2Te-Te-Ag2Te nanowires

    Science.gov (United States)

    Som, Anirban; Pradeep, T.

    2012-07-01

    Growth of isolated axial heterojunction nanowires by a solution phase growth process is reported. The dumb-bell shaped nanowires contain two silver telluride sections at the extremes joined by a tellurium section. Reaction of silver nitrate with tellurium NWs in aqueous solution at a molar ratio of 1 : 1 leads to the formation of amorphous partially silver reacted Te NWs. Low temperature (75 °C) solution phase annealing of these silver deficient NWs results in phase segregation producing crystalline Ag2Te and Te phases with clear phase boundaries along the wire axis. Structural characterization of these dumb-bell shaped NWs was performed with different microscopic and spectroscopic tools. Solution phase silver concentration over the course of annealing indicated leaching of silver into the solution during the formation of biphasic NWs. Similar Ag : Te ratios were observed in both partially silver reacted Te NWs and phase segregated Ag2Te-Te-Ag2Te NWs and this was attributed to redeposition of leached silver on the amorphous NW tips which eventually resulted in complete phase segregation. Successful integration of different chemical components in single NWs is expected to open up new application possibilities as physical and chemical properties of the heterostructure can be exploited.Growth of isolated axial heterojunction nanowires by a solution phase growth process is reported. The dumb-bell shaped nanowires contain two silver telluride sections at the extremes joined by a tellurium section. Reaction of silver nitrate with tellurium NWs in aqueous solution at a molar ratio of 1 : 1 leads to the formation of amorphous partially silver reacted Te NWs. Low temperature (75 °C) solution phase annealing of these silver deficient NWs results in phase segregation producing crystalline Ag2Te and Te phases with clear phase boundaries along the wire axis. Structural characterization of these dumb-bell shaped NWs was performed with different microscopic and spectroscopic

  17. Dissociation energies of Ag-RG (RG = Ar, Kr, Xe) and AgO molecules from velocity map imaging studies.

    Science.gov (United States)

    Cooper, Graham A; Kartouzian, Aras; Gentleman, Alexander S; Iskra, Andreas; van Wijk, Robert; Mackenzie, Stuart R

    2015-09-28

    The near ultraviolet photodissociation dynamics of silver atom-rare gas dimers have been studied by velocity map imaging. Ag-RG (RG = Ar, Kr, Xe) species generated by laser ablation are excited in the region of the C ((2)Σ(+))←X ((2)Σ(+)) continuum leading to direct, near-threshold dissociation generating Ag* ((2)P3/2) + RG ((1)S0) products. Images recorded at excitation wavelengths throughout the C ((2)Σ(+))←X ((2)Σ(+)) continuum, coupled with known atomic energy levels, permit determination of the ground X ((2)Σ(+)) state dissociation energies of 85.9 ± 23.4 cm(-1) (Ag-Ar), 149.3 ± 22.4 cm(-1) (Ag-Kr), and 256.3 ± 16.0 cm(-1) (Ag-Xe). Three additional photolysis processes, each yielding Ag atom photoproducts, are observed in the same spectral region. Two of these are markedly enhanced in intensity upon seeding the molecular beam with nitrous oxide, and are assigned to photodissociation of AgO at the two-photon level. These features yield an improved ground state dissociation energy for AgO of 15 965 ± 81 cm(-1), which is in good agreement with high level calculations. The third process results in Ag atom fragments whose kinetic energy shows anomalously weak photon energy dependence and is assigned tentatively to dissociative ionization of the silver dimer Ag2.

  18. Preparation of mesoporous Ag/AgBr/TiO2 nanocomposites with comb-type polymer as template

    Directory of Open Access Journals (Sweden)

    Li XU

    Full Text Available The mesoporous TiO2 nanocomposites were fabricated in a water bath at lower temperatures using the sol-gel method with a comb-type polymer as template and tetrabutyl titanate as Ti source. The Ag/AgBr/TiO2 nanocomposites with higher specific surface areas were obtained by the introduction of Ag/AgBr on the surface of the mesoporous TiO2 using a deposition-precipitation method. The as-prepared nanocomposites were characterized by X-ray diffraction (XRD, N2 sorption analysis, transmission electron microscope (TEM and UV-vis diffuse reflectance spectroscopy (UV-vis DRS. The results showed that both the as-prepared TiO2 and Ag/AgBr/TiO2 exhibited mesoporous structure. The introduction of Ag/AgBr not only decreased the specific surface area of the mesoporous TiO2 from 346 m2/g to 253 m2/g, but also significantly increased its visible light photocatalytic activity. The degradation rate of methyl orange under visible light irradiation over Ag/AgBr/TiO2 was 145 and 60 times of those over the commercial TiO2 P25 and the mesoporous TiO2, respectively.

  19. Ag surface diffusion and out-of-bulk segregation in CrN-Ag nano-composite coatings.

    Science.gov (United States)

    Incerti, L; Rota, A; Ballestrazzi, A; Gualtieri, E; Valeri, S

    2011-10-01

    CrN-Ag nanocomposite coatings are deposited on Si(100) wafers and 20MnCr5 steel disks in a mixed Ar+N2 atmosphere by reactive magnetron sputtering. Structure, composition and morphology were investigated by Scanning Electron Microscopy (SEM), Auger Electron Spectroscopy (AES), X-ray Photoemission Spectroscopy (XPS), X-ray Diffraction (XRD) and Focused Ion Beam (FIB) cross sectional analysis. The as deposited film matrix is mainly composed by CrN phase (78%), but a relevant part (28%) is composed by Cr2N. Ag agglomerates in the CrN matrix forming elongated grains 200-400 nm wide and 50-100 nm high, which extends on the top of CrN columns. At the surface Ag aggregates into two different structures: large tetrahedral crystalline clusters, with typical dimension ranging from 200 to 500 nm, and smaller Ag nanoparticles with diameter of 15-25 nm. The annealing in N2 atmosphere up to 500 degrees C does not affect size and distribution of the Ag grains in the sub-surface region, while it induces a size increase of the bigger Ag clusters on the surface, mainly related to Ag surface diffusion and clusters coalescence. Annealing at higher temperature leads to an evident Ag out-of-bulk segregation, generating Ag depleted voids in the near-surface region, and further increasing of the Ag clusters size at the surface. Tribological tests on as deposited CrN-Ag film reveal a coefficient of friction against a steel ball reduced with respect to CrN film, probably related to the presence of Ag which acts as solid lubricant, but the coating is removed after a very short sliding distance. The poor mechanical properties of the realized Ag-based coatings are confirmed by lower hardness and Young modulus values with respect to pure CrN.

  20. Chronically Implanted, Nafion-Coated Ag/AgCl Reference Electrodes for Neurochemical Applications.

    Science.gov (United States)

    Hashemi, Parastoo; Walsh, Paul L; Guillot, Thomas S; Gras-Najjar, Julie; Takmakov, Pavel; Crews, Fulton T; Wightman, R Mark

    2011-11-16

    Fast-scan cyclic voltammetry (FSCV) at carbon fiber microelectrodes can be used to measure behaviorally correlated dopamine changes in the extracellular fluid of the brain of freely moving rats. These experiments employ a chronically implanted Ag/AgCl reference electrode. When dopamine measurements are taken 4 days after implantation, there is often a potential shift, typically greater than +0.2 V, in the anodic and cathodic peaks in the cyclic voltammogram for dopamine. In this work, we optimized a method to coat sintered Ag/AgCl reference electrodes with the perfluorinated polymer, Nafion, to prevent this shift. We find that we can stabilize reference electrodes for up to 28 days. Immunohistochemistry of the tissue around the implant site shows extensive glial encapsulation around both bare and Nafion-coated devices. However, the lesion around bare electrodes has a rough texture implying that these cells are strongly adsorbed onto the bare reference electrode, while the lesion around a Nafion-coated electrode shows that cells are more intact implying that they adsorb less strongly. EDS and SEM analysis of the surface of the electrodes confirms this by visualizing a heavy build up of plaques, organic in nature, only on bare electrodes. Impedance spectroscopy indicates no difference between the impedance of bare and Nafion-coated Ag/AgCl electrodes, indicating that glial encapsulation does not lead to an increase in uncompensated resistance between the working and reference electrodes. The electrochemical shift therefore must be due to the unique chemical microenvironment around the reference electrode that alters the chloride equilibrium, a process that the Nafion coating prevents.

  1. Mechanical Properties of (Bi,Pb)-2223 Multifilament Tapes with Ag-Alloy Sheath

    Institute of Scientific and Technical Information of China (English)

    LIANG Ting; QU Ti-Ming; LI Pei; HAN Zheng-He

    2006-01-01

    @@ Ag-Mg-V alloy is prepared and investigated to develop a new sheath alloy used for BSCCO tapes. Bi-2223 Ag/AgMgV and Bi-2223 AgMgV/AgMgV tapes are studied with the help of stress-strain measurement, optical microstructure and critical current Ic.

  2. High Activity of Hexagonal Ag/Pt Nanoshell Catalyst for Oxygen Electroreduction

    Directory of Open Access Journals (Sweden)

    Lee Chien-Liang

    2008-01-01

    Full Text Available Abstract Hexagonal Ag/Pt nanoshells were prepared by using a hexagonal Ag nanoplate as the displacement template and by introducing Pt ions. The prepared Ag/Pt nanoshells played the role of an electrocatalyst in an oxygen reduction process. Compared to spherical Pt and Ag/Pt nanoparticles, the hexagonal Ag/Pt nanoshells showed higher activity for oxygen electroreduction.

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

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

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

  4. Strongly visible-light responsive plasmonic shaped AgX:Ag (X = Cl, Br) nanoparticles for reduction of CO2 to methanol.

    Science.gov (United States)

    An, Changhua; Wang, Jizhuang; Jiang, Wen; Zhang, Meiyu; Ming, Xijuan; Wang, Shutao; Zhang, Qinhui

    2012-09-21

    Plasmonic shaped AgX:Ag (X = Cl, Br) nanoparticles have been synthesized by a facile and versatile glycerol-mediated solution route. The as-prepared AgX:Ag nanoparticles exhibit regular shapes, i.e., cube-tetrapod-like AgCl:Ag nanoparticles and AgBr:Ag nanoplates. Compared with the pristine AgX, AgX:Ag nanocomposites display stronger absorption in the visible region due to the surface plasmon resonance of silver nanoparticles. The calculation of bandgaps and band positions indicates the as-achieved AgX:Ag nanoparticles can be used as a class of potential photocatalyst for the reduction of CO(2). For example, reduction of CO(2) under visible light irradiation with the assistance of the anisotropic AgX:Ag nanoparticles yields as much as 100 μmol methanol in the products. Furthermore, the AgX:Ag nanoparticles can maintain its structure and activity after 3 runs of reactions. Therefore, the present route opens an avenue to acquire plasmonic photocatalysts for conversion of CO(2) into useful organic compounds.

  5. Nano Ag@AgBr surface-sensitized Bi{sub 2}WO{sub 6} photocatalyst: oil-in-water synthesis and enhanced photocatalytic degradation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Shuanglong; Liu, Li; Hu, Jinshan; Liang, Yinghua, E-mail: liangyh@heuu.edu.cn; Cui, Wenquan, E-mail: wkcui@163.com

    2015-01-01

    Graphical abstract: - Highlights: • The plasmatic Ag@AgBr surface-sensitized Bi{sub 2}WO{sub 6} composite photocatalysts. • Ag@AgBr greatly increased visible-light absorption for Bi{sub 2}WO{sub 6}. • The plasmonic photocatalysts exhibited enhanced activity for the degradation of MB, phenol and salicylic acid. - Abstract: Nano Ag@AgBr decorated on the surface of flower-like Bi{sub 2}WO{sub 6} (hereafter designated Ag@AgBr/Bi{sub 2}WO{sub 6}) were prepared via a facile oil-in-water self-assembly method. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectroscopy (DRS), etc. The characterization results indicated that nano Ag@AgBr was observed to be evenly dispersed on the surface of Bi{sub 2}WO{sub 6}, and was approximately 20 nm in size. Ag@AgBr/Bi{sub 2}WO{sub 6} composites exhibited excellent UV–vis absorption, due to quantum dimension effect of Ag@AgBr, the surface plasmonic resonance (SPR) of Ag nanoparticles and the special flower-like structure of Bi{sub 2}WO{sub 6}. The photoelectrochemical measurement verified that the suitable band potential of Ag@AgBr and Bi{sub 2}WO{sub 6} and the existence of metal Ag resulted in the high efficiency in charge separation of the composite. The photocatalytic activities of the Ag@AgBr/Bi{sub 2}WO{sub 6} samples were examined under visible-light irradiation for the degradation of methylene blue (MB). The composite presented excellent photocatalytic activity due to the synergetic effect of Bi{sub 2}WO{sub 6}, AgBr, and Ag nanoparticles. The Ag@AgBr(20 wt.%)/Bi{sub 2}WO{sub 6} sample exhibited the best photocatalytic activity, degrading 95.03% MB after irradiation for 2 h, which was respectively 1.29 times and 1.28 times higher than that of Ag@AgBr and Bi{sub 2}WO{sub 6} photocatalyst. Meanwhile, phenol and salicylic acid were degraded to further prove the degradation ability of Ag@AgBr/Bi{sub 2

  6. KOEKSISTENSI HBsAg DAN ANTI-HBs DI MAKASSAR

    OpenAIRE

    uleng, -

    2015-01-01

    - Infeksi virus hipatitis B (VHB) merupakan penyakit endemik dengan insidensi tinggi di indonesia dan merupakan persoalan kesehatan global. Virus hepatitis B adalah suatu virus DNA yang berlapis ganda (double shelled) yang terdiri dari bagian luar yang dikenal sebagai hepatitis B surface antigen (HbsAG) dan bagian dalam atau hepatitis core antigen (HbcAg). Keberadaan HbsAg dalam serum merupakan tanda infeksi VHB. pembersihan VHB ditandai dengan didapatkannya anti-HBs dalam serum. Anti...

  7. Transport of silver nanoparticles (AgNPs) in soil.

    Science.gov (United States)

    Sagee, Omer; Dror, Ishai; Berkowitz, Brian

    2012-07-01

    The effect of soil properties on the transport of silver nanoparticles (AgNPs) was studied in a set of laboratory column experiments, using different combinations of size fractions of a Mediterranean sandy clay soil. The AgNPs with average size of ~30nm yielded a stable suspension in water with zeta potential of -39mV. Early breakthrough of AgNPs in soil was observed in column transport experiments. AgNPs were found to have high mobility in soil with outlet relative concentrations ranging from 30% to 70%, depending on experimental conditions. AgNP mobility through the column decreased when the fraction of smaller soil aggregates was larger. The early breakthrough pattern was not observed for AgNPs in pure quartz columns nor for bromide tracer in soil columns, suggesting that early breakthrough is related to the nature of AgNP transport in natural soils. Micro-CT and image analysis used to investigate structural features of the soil, suggest that soil aggregate size strongly affects AgNP transport in natural soil. The retention of AgNPs in the soil column was reduced when humic acid was added to the leaching solution, while a lower flow rate (Darcy velocity of 0.17cm/min versus 0.66cm/min) resulted in higher retention of AgNPs in the soil. When soil residual chloride was exchanged by nitrate prior to column experiments, significantly improved mobility of AgNPs was observed in the soil column. These findings point to the importance of AgNP-soil chemical interactions as a retention mechanism, and demonstrate the need to employ natural soils rather than glass beads or quartz in representative experimental investigations.

  8. Rare and forbidden kaon decays at the AGS

    Energy Technology Data Exchange (ETDEWEB)

    Kettell, S.

    1997-12-09

    An overview of the Rare Kaon Decay program at the AGS is presented, with particular emphasis on the three major experiments currently running and analyzing data. A brief overview of earlier kaon decay experiments and of the AGs performance improvements is also provided. This review concludes with a discussion of proposed and developing experiments planned to run in the year 2000 and beyond (AGS-2000).

  9. The Multiplication Group of an AG-group

    OpenAIRE

    Shah, Muhammad; Ali, Asif; Ahmad, Imtiaz; Sorge, Volker

    2014-01-01

    We investigate the multiplication group of a special class of quasigroup called AG-group. We prove some interesting results such as: the multiplication group of an AG-group of order n is non-abelian group of order 2n and its left section is an abelian group of order n. The inner mapping group of an AG-group of any order is a cyclic group of order 2.

  10. Ag/AgCl纳米枝状结构的制备及其光催化性能研究%Synthesis of dendritic Ag/AgCl nanostructures and their photocatalytic properties

    Institute of Scientific and Technical Information of China (English)

    李高英; 刘颖; 母建林; 任卫安; 刘鹏; 文晓刚

    2012-01-01

    In this article, a novel surfactant-free method to synthesize Ag/AgCl dendrite nanostructures. In this method, we used DESs as solvent, sodium citrate as reducing agent, chloroauric acid as seed, silver nitrate as silver source respectively. The products were characterized by SEM, XRD, EDS and their photocatalytic property was measured. It was found that the perfect nanodendrites could be obtained at 160℃ after 24h reaction. The formation of final dendrite nanostructures can be explained by a trans-formation process from AgCl to Ag. Companying the increasing reaction time, the decrease of AgCl and increase of Ag could be found. Due to the presense of AgCl, the products have good photocatalytic performance.%采用离子液体法,以离子液体(DESs)为溶剂,柠檬酸三钠为还原剂,氯金酸为晶种,硝酸银为银源,制备了Ag/AgCl纳米枝状结构。利用SEM、XRD、EDS对样品的形貌、成分、结构进行了表征分析,并测试了样品的光催化性能。结果表明,当反应温度为160℃,反应时间为24h时,可获得完整的Ag/AgCl纳米枝状结构;枝状结构的形成是基于AgCl在还原剂作用下不断向Ag转换过程的结果;产物具有较好的光催化效果,并且随着反应时间的延长,产物的光催化性能减弱。

  11. AG Pegasi - now a classical symbiotic star in outburst?

    Science.gov (United States)

    Tomov, T. V.; Stoyanov, K. A.; Zamanov, R. K.

    2016-11-01

    Optical spectroscopy study of the recent AG Pegasi (AG Peg) outburst observed during the second half of 2015 is presented. Considerable variations of the intensity and the shape of the spectral features as well as the changes of the hot component parameters, caused by the outburst, are discussed and certain similarities between the outburst of AG Peg and the outburst of a classical symbiotic stars are shown. It seems that after the end of the symbiotic nova phase, AG Peg became a member of the classical symbiotic stars group.

  12. Critical current and electronic properties of YBCO-Ag compounds

    Energy Technology Data Exchange (ETDEWEB)

    Dwir, B.; Affronte, M.; Pavuna, D. (Physics Dept., Swiss Federal Inst. of Tech., Lausanne (Switzerland))

    1989-12-01

    We have found that in YBCO-Ag ceramic compounds Ag fills the intergranular space (''holes'') without affecting Tc. Normal-state resistivity is decreased by {approx equal} x 100 when adding up to 50 wt% Ag. Percolation analysis shows that the critical indices t,s are in agreement with 3D theoretical values, but p{sub c} is higher than expected. The critical current density J{sub c} is enhanced by up to 50% in the samples containing {approx equal} 10 wt% Ag, this enhancement corresponds to a maximum YBCO compactness in the samples. (orig.).

  13. RHIC FY15 pp Run RHIC and AGS polarization analysis

    Energy Technology Data Exchange (ETDEWEB)

    Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Adams, P. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-02-20

    The polarization information is important for the spin physics program in Relativistic Heavy Ion Collider (RHIC). There are discrepancies between AGS and RHIC polarization measurements. First, the face value of AGS polarization is higher than RHIC ones in general. Second, the measured polarization profile (described by the profile ratio R) is stronger in AGS than in RHIC. This note analyzes the polarization data from FY15 pp run period. The results show that the differences between AGS and RHIC polarization measurements are reasonable, but the R value difference is puzzling. The difference between blue and yellow ring is worth of spin simulation to explain.

  14. Phytotoxicity of Ag nanoparticles prepared by biogenic and chemical methods

    Science.gov (United States)

    Choudhury, Rupasree; Majumder, Manna; Roy, Dijendra Nath; Basumallick, Srijita; Misra, Tarun Kumar

    2016-06-01

    Silver nanoparticles (Ag NPs) are now widely used as antibacterial and antifungal materials in different consumer products. We report here the preparation of Ag NPs by neem leaves extract ( Azadirachta) reduction and trisodium citrate-sodium borohydride reduction methods, and study of their phytotoxicity. The nanoparticles were characterized by UV-Vis spectroscopy, FTIR, and atomic force microscopy (AFM) techniques. Both neem-coated and citrate-coated Ag NPs exhibit surface plasmon around 400 nm, and their average sizes measured by AFM are about 100 and 20 nm, respectively. Antibacterial and antifungal activities of these nanomaterials have been studied by simple pea seed germination and disk diffusion methods. It has been observed from the growth of root and shoot, citrate-coated Ag NPs significantly affect seedling growth, but neem-coated Ag NPs exhibit somehow mild toxicity toward germination process due to the nutrient supplements from neem. On the other hand, antifungal activity of neem-coated Ag NPs has been found much higher than that of citrate-coated Ag NPs due to the combined effects of antifungal activity of neem and Ag NPs. Present research primarily indicates a possible application of neem-coated Ag NPs as a potential fungicide.

  15. Zwitterionic phosphorylcholine-protected water-soluble Ag nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The water-soluble Ag nanoparticles capped with novel zwitterionic thioalkylated phosphorylcholine were synthesized.The Ag nanoparticles showed remarkable stability in saline media with salt concen-trations as high as 2.0 mol/L and plasma using UV-vis absorption spectroscopy.Similarly,compared with tiopronin and citrate-protected Ag nanoparticles,the zwitterionic phosphorylcholine Ag nanopar-ticles did not precipitate out of solution when charged polyelectrolytes or biopolymers were added.The zwitterionic phosphorylcholine might be a better ligand for stabilizing metal nanoparticles.

  16. Electrochemical behavior of cast Ti-Ag alloys.

    Science.gov (United States)

    Takahashi, Masatoshi; Kikuchi, Masafumi; Takadai, Yukyo; Okabe, Toru; Okuno, Osamu

    2006-09-01

    Anodic polarization tests were performed in 0.9% NaCl and 1% lactic acid solutions to characterize the relationship between the corrosion behavior and the microstructures of cast Ti-Ag (5-40% Ag) alloys. The anodic polarization curves for the Ti-Ag alloys up to 17.5% Ag were similar to those for pure titanium in both solutions. On the other hand, an abrupt increase in the current density was observed for the alloys with more than 20% Ag in the NaCl solution and with more than 27.5% Ag in the lactic acid solution. The microstructures of the corroded alloy surfaces indicated the deterioration of precipitated intermetallic compounds along the grain boundaries. The Ti-Ag alloys up to 17.5% Ag had excellent corrosion resistance similar to that of pure titanium. The alloys with 20-25% Ag may be also used as dental alloys, since they passivated again immediately after preferential dissolution in the NaCl solution.

  17. Molecular dynamics study of nanojoining between axially positioned Ag nanowires

    Science.gov (United States)

    Cui, Jianlei; Theogene, Barayavuga; Wang, Xuewen; Mei, Xuesong; Wang, Wenjun; Wang, Kedian

    2016-08-01

    The miniaturization of electronics devices into nanometer scale is indispensable for next-generation semiconductor technology. Ag nanowires (Ag NWs) are considered to be the promising candidates for future electronic circuit owing to the excellent electrical and thermal properties. The nanojoining of axially positioned Ag NWs was performed by molecular dynamics simulation. Through the detailed atomic evolution during the nanojoining, the results indicate that the temperature and the distance between Ag NWs in axial direction have a great impact on nanojoining effect. When the nanojoining temperature is relatively high, the atoms are disordered and the atomic queues become to distort with strong thermodynamic properties and weak effect of metal bonds. At the relatively low temperature, the Ag NWs can be well connected with good junction quality and their own morphology, which is similar to the cold welding without fusion, while the distance between Ag NWs should be controlled for interaction and diffusion of interfacial atoms at nanowires head. When the Ag NWs are placed on Si and SiO2 substrate, because the atomic species and lattice structure of substrate material can differently affect the motions of Ag atoms through the interactive force between the atoms, the nanojoining quality of Ag NWs on Si substrate is better than that on the SiO2 substrate. So, for getting effective and reliable nanojoining without nanosolders and other materials, the temperature, distance and substrate surface should be reasonably controlled and selected, providing helpful theoretical guidance for experiment and application of nanojoining.

  18. Safe and Effective Ag Nanoparticles Immobilized Antimicrobial NanoNonwovens

    DEFF Research Database (Denmark)

    Song, Jie; Chen, Menglin; Regina, Viduthalai R.

    2012-01-01

    and possibility of introduction of secondary pollution. Here, we present a novel strategy to produce a safe and effective antimicrobial nanononwoven material by immobilizing AgNPs on a rigid polymer nanofibrous matrix through simple co-electrospinning of pre-prepaired AgNPs and polystyrene (PS). Distribution...... of the AgNPs on the surface of PS fibers was achieved by tuning fiber diameters during electrospinning. Atomic force microscopy (AFM) analysis revealed that the AgNPs distributed at the fiber surface were still covered by a layer of polymer, which inhibited their antimicrobial activity. UV/ozone treatment...

  19. Research on the Preparation,Property and Application of the Coated Wire Ag-Ag2S Ion Selective Electrode%涂丝Ag-Ag2S电极的制备、性能与应用研究

    Institute of Scientific and Technical Information of China (English)

    董红霞; 杜宝中; 姚秉华; 薛力

    2004-01-01

    介绍了涂丝Ag-Ag2S电极的响应机理及其制备方法,并测试了其电化学性能.结果表明,涂丝Ag-Ag2S电极与商品固膜硫离子选择电极具有同等的灵敏度、准确度和精密度,而且其制备方法简便,再生性好,造价低廉.

  20. Plasmon-assisted degradation of methylene blue with Ag/AgCl/montmorillonite nanocomposite under visible light.

    Science.gov (United States)

    Sohrabnezhad, Sh; Zanjanchi, M A; Razavi, M

    2014-09-15

    Metal-semiconductor compounds, such as Ag/AgX (X=Cl, Br, I), enable visible light absorption and separation of photogenerated electron-hole through surface plasmon resonance (SPR) effect. However, the electron-hole generated and separated by light are vulnerable in Ag/AgX phase because of the occurrence of secondary recombined. In order to more effectively utilize the SPR photocatalytic effect, nanoparticles are located in a matrix. In this article, Ag/AgCl nanoparticles were synthesized in montmorillonite (MMT) matrix using dispersion method and light irradiation. The structure, composition and optical properties of such material were investigated by transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), X-ray diffraction (XRD) and FTIR. Powder X-ray diffraction showed intercalation of Ag/AgCl nanoparticles into the clay layers. The as-prepared plasmonic photocatalyst exhibited an enhanced and stable photoactivity for the degradation of methylene blue (MB) under visible light. The high activity was attributed to the surface plasmon resonance (SPR) exhibited by Ag nanoparticles on the surface of AgCl. The detection of reactive species by radical scavengers displays that O2- and OH- are the main reactive species for the degradation of MB under visible light irradiation. The studies showed that 20 min illumination under visible light can complete degradation of methylene blue (MB), and indicate a high stability of photocatalytic degradation. The mechanism of separation of the photo-generated electrons and holes at the Ag/AgCl-MMT nanocomposite was discussed.

  1. Plasmon-assisted degradation of methylene blue with Ag/AgCl/montmorillonite nanocomposite under visible light

    Science.gov (United States)

    Sohrabnezhad, Sh.; Zanjanchi, M. A.; Razavi, M.

    2014-09-01

    Metal-semiconductor compounds, such as Ag/AgX (X = Cl, Br, I), enable visible light absorption and separation of photogenerated electron-hole through surface plasmon resonance (SPR) effect. However, the electron-hole generated and separated by light are vulnerable in Ag/AgX phase because of the occurrence of secondary recombined. In order to more effectively utilize the SPR photocatalytic effect, nanoparticles are located in a matrix. In this article, Ag/AgCl nanoparticles were synthesized in montmorillonite (MMT) matrix using dispersion method and light irradiation. The structure, composition and optical properties of such material were investigated by transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), X-ray diffraction (XRD) and FTIR. Powder X-ray diffraction showed intercalation of Ag/AgCl nanoparticles into the clay layers. The as-prepared plasmonic photocatalyst exhibited an enhanced and stable photoactivity for the degradation of methylene blue (MB) under visible light. The high activity was attributed to the surface plasmon resonance (SPR) exhibited by Ag nanoparticles on the surface of AgCl. The detection of reactive species by radical scavengers displays that rad O2- and rad OH- are the main reactive species for the degradation of MB under visible light irradiation. The studies showed that 20 min illumination under visible light can complete degradation of methylene blue (MB), and indicate a high stability of photocatalytic degradation. The mechanism of separation of the photo-generated electrons and holes at the Ag/AgCl-MMT nanocomposite was discussed.

  2. AgPi: Agents on Raspberry Pi

    Directory of Open Access Journals (Sweden)

    Tushar Semwal

    2016-10-01

    Full Text Available The Raspberry Pi and its variants have brought with them an aura of change in the world of embedded systems. With their impressive computation and communication capabilities and low footprint, these devices have thrown open the possibility of realizing a network of things in a very cost-effective manner. While such networks offer good solutions to prominent issues, they are indeed a long way from being smart or intelligent. Most of the currently available implementations of such a network of devices involve a centralized cloud-based server that contributes to making the necessary intelligent decisions, leaving these devices fairly underutilized. Though this paradigm provides for an easy and rapid solution, they have limited scalability, are less robust and at times prove to be expensive. In this paper, we introduce the concept of Agents on Raspberry Pi (AgPi as a cyber solution to enhance the smartness and flexibility of such embedded networks of physical devices in a decentralized manner. The use of a Multi-Agent System (MAS running on Raspberry Pis aids agents, both static and mobile, to govern the various activities within the network. Agents can act autonomously or on behalf of a human user and can collaborate, learn, adapt and act, thus contributing to embedded intelligence. This paper describes how Tartarus, a multi-agent platform, embedded on Raspberry Pis that constitute a network, can bring the best out of the system. To reveal the versatility of the concept of AgPi, an application for a Location-Aware and Tracking Service (LATS is presented. The results obtained from a comparison of data transfer cost between the conventional cloud-based approach with AgPi have also been included.

  3. METAL MEDIA FILTERS, AG-1 SECTION FI

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D.

    2012-05-23

    One application of metal media filters is in various nuclear air cleaning processes including applications for protecting workers, the public and the environment from hazardous and radioactive particles. To support this application the development of the ASME AG-1 FI Standard on Metal Media has been under way for more than ten years. Development of the proposed section has required resolving several difficult issues associated with operating conditions (media velocity, pressure drop, etc.), qualification testing, and quality acceptance testing. Performance characteristics of metal media are dramatically different than the glass fiber media with respect to parameters like differential pressures, operating temperatures, media strength, etc. These differences make existing data for a glass fiber media inadequate for qualifying a metal media filter for AG-1. In the past much work has been conducted on metal media filters at facilities such as Lawrence Livermore National Laboratory (LLNL) and Savannah River National Laboratory (SRNL) to qualify the media as High Efficiency Particulate Air (HEPA) Filters. Particle retention testing has been conducted at Oak Ridge Filter Test Facility and at Air Techniques International (ATI) to prove that the metal media meets or exceeds the 99.97% particle retention required for a HEPA Filter. Even with his testing, data was lacking to complete an AG-1 FI Standard on metal media. With funding secured by Mississippi State University (MSU) from National Nuclear Security Administration (NNSA), a research test stand is being designed and fabricated at MSU's Institute for Clean Energy Technology (ICET) Facility to obtain qualification data on metal media. This in turn will support required data needed for the FI Standard. The paper will discuss in detail how the test stand at MSU will obtain the necessary data to complete the FI Standard.

  4. Nano-galvanic coupling for enhanced Ag+ release in ZrCN-Ag films : Antibacterial application

    NARCIS (Netherlands)

    Calderon, S.; Ferreri, I.; Henriques, M.; De Hosson, J. T. M.; Cavaleiro, A.; Carvalho, S.

    2016-01-01

    The antibacterial properties of materials developed for medical devices with embedded silver nanoparticles are enhanced by controlling the release of silver ions. In this study, a simple experimental procedure for the augmentation of the silver ion release from ZrCN-Ag coatings is described. The sil

  5. Fabrication of antimicrobial bacterial cellulose-Ag/AgCl nanocomposite using bacteria as versatile biofactory

    Energy Technology Data Exchange (ETDEWEB)

    Liu Chuang [Tianjin University, Key Laboratory for Green Technology, School of Chemical Engineering and Technology (China); Yang Dong; Wang Yuangui [Tianjin University, Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of Ministry of Education, School of Chemical Engineering and Technology (China); Shi Jiafu; Jiang Zhongyi, E-mail: zhyjiang@tju.edu.cn [Tianjin University, Key Laboratory for Green Technology, School of Chemical Engineering and Technology (China)

    2012-08-15

    In nature, a number of nanocomposites are formed through biomineralization-relevant processes under mild conditions. In the present study, a total 'biologic' route to fabricate nanocomposite is reported. Non-pathogenic bacteria, Gluconacetobacter xylinum, was utilized as a versatile biofactory, which produced biopolymer bacterial cellulose (BC) and induced the formation of Ag/AgCl nanoparticles, yielding BC-Ag/AgCl nanocomposite. Scanning electron microscopy revealed that nanoparticles with average size of 17.4 nm were randomly embedded into the BC network; transmission electron microscopy and X-ray diffraction confirmed that the nanoparticles were mixtures of face-centered cubic silver and silver chloride nanoparticles. Moreover, the content of silver in the BC nanocomposite is around 0.05 wt%, determined by atomic absorption spectrometry and X-ray photoelectron spectroscopy analysis. The entire process of nanocomposite fabrication was conducted at ambient environment without utilizing toxic agents or producing hazardous products, which is not only environmentally friendly but also with less chances to generate harmful products to human bodies as biomedical materials. The resultant nanocomposite displayed the desirable activity in inhibiting bacterial growth of both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli microorganisms on agar plate and in liquid culture, indicating the potential of the material as antimicrobial wound dressing materials. This work demonstrated the feasibility of using microorganism to fabricate nanocomposite, especially for biomedical materials.

  6. Ag/AgBr/Co-Ni-NO3 layered double hydroxide nanocomposites with highly adsorptive and photocatalytic properties.

    Science.gov (United States)

    Fan, Hai; Zhu, Jianying; Sun, Jianchao; Zhang, Shenxiang; Ai, Shiyun

    2013-02-11

    A facile anion-exchange precipitation method was used to synthesize bifunctional Ag/AgBr/Co-Ni-NO(3) layered double hydroxide (LDH) nanocomposites by adding AgNO(3) solution to a suspension of Co-Ni-Br LDH. The Ag/AgBr nanoparticles were highly dispersed on the sheets of Co-Ni-NO(3) LDH. The prepared nanocomposites were used to adsorb and photocatalytically degrade organic pollutants from water. Without light illumination, the nanocomposites quickly adsorbed methyl orange, and the adsorptive capacity, which can reach 230 mg g(-1), is much higher than those of Co-Ni-Br LDH, Ag/AgBr, and activated carbon. The photocatalytic activities of the nanocomposites for the removal of dyes and phenol are higher than those of Co-Ni-Br LDH and Ag/AgBr. The proposed method can be applied to prepare other LDH/silver salt composites. The high absorptive capacity and good photocatalytic activity of such nanostructures could have wide applications in wastewater treatment.

  7. Comparison of antibacterial activities of Ag@TiO2 and Ag@SiO2 core-shell nanoparticles

    Science.gov (United States)

    Dhanalekshmi, K. I.; Meena, K. S.

    2014-07-01

    Core-shell type Ag@TiO2 nanoparticles were prepared by one pot simultaneous reduction of AgNO3 and hydrolysis of Ti (IV) isopropoxide and Ag@SiO2 core-shell nanoparticles were prepared by Stober's method. They were characterized by absorption, XRD, and HR-TEM techniques. XRD patterns show the presence of anatase form of TiO2 and amorphous form of SiO2 and the noble metal (Ag). High resolution transmission electron microscopy measurements revealed that their size is below 50 nm. The antibacterial properties of Ag@TiO2 and Ag@SiO2 core-shell nanoparticles against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were examined by the agar diffusion method. As a result E. coli and S. aureus were shown to be substantially inhibited by Ag@TiO2 and Ag@SiO2 core-shell nanoparticles. These results demonstrated that TiO2 and SiO2 supported on the surface of Ag NPs without aggregation was proved to have enhanced antibacterial activity.

  8. Comparison of antibacterial activities of Ag@TiO2 and Ag@SiO2 core-shell nanoparticles.

    Science.gov (United States)

    Dhanalekshmi, K I; Meena, K S

    2014-07-15

    Core-shell type Ag@TiO2 nanoparticles were prepared by one pot simultaneous reduction of AgNO3 and hydrolysis of Ti (IV) isopropoxide and Ag@SiO2 core-shell nanoparticles were prepared by Stober's method. They were characterized by absorption, XRD, and HR-TEM techniques. XRD patterns show the presence of anatase form of TiO2 and amorphous form of SiO2 and the noble metal (Ag). High resolution transmission electron microscopy measurements revealed that their size is below 50 nm. The antibacterial properties of Ag@TiO2 and Ag@SiO2 core-shell nanoparticles against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were examined by the agar diffusion method. As a result E. coli and S. aureus were shown to be substantially inhibited by Ag@TiO2 and Ag@SiO2 core-shell nanoparticles. These results demonstrated that TiO2 and SiO2 supported on the surface of Ag NPs without aggregation was proved to have enhanced antibacterial activity.

  9. Identification of Ag-acceptors in $^{111}Ag^{111}Cd$ doped ZnTe and CdTe

    CERN Document Server

    Hamann, J; Deicher, M; Filz, T; Lany, S; Ostheimer, V; Strasser, F; Wolf, H; Wichert, T

    2000-01-01

    Nominally undoped ZnTe and CdTe crystals were implanted with radioactive /sup 111/Ag, which decays to /sup 111/Cd, and investigated by photoluminescence spectroscopy (PL). In ZnTe, the PL lines caused by an acceptor level at 121 meV are observed: the principal bound exciton (PBE) line, the donor-acceptor pair (DAP) band, and the two-hole transition lines. In CdTe, the PBE line and the DAP band that correspond to an acceptor level at 108 meV appear. Since the intensities of all these PL lines decrease in good agreement with the half-life of /sup 111/Ag of 178.8 h, both acceptor levels are concluded to be associated with defects containing a single Ag atom. Therefore, the earlier assignments to substitutional Ag on Zn- and Cd-lattice sites in the respective II-VI semiconductors are confirmed. The assignments in the literature of the S/sub 1/, S /sub 2/, and S/sub 3/ lines in ZnTe and the X/sub 1//sup Ag/, X/sub 2 //sup Ag//C/sub 1//sup Ag/, and C/sub 2//sup Ag/ lines in CdTe to Ag- related defect complexes are ...

  10. Micro-PIXE study of Ag in digestive glands of a nano-Ag fed arthropod ( Porcellio scaber, Isopoda, Crustacea)

    Science.gov (United States)

    Tkalec, Živa Pipan; Drobne, Damjana; Vogel-Mikuš, Katarina; Pongrac, Paula; Regvar, Marjana; Štrus, Jasna; Pelicon, Primož; Vavpetič, Primož; Grlj, Nataša; Remškar, Maja

    2011-10-01

    Micro-proton induced X-ray emission (micro-PIXE) method was applied to study the micro-localization of silver (Ag) in digestive glands of a terrestrial arthropod (Porcellio scaber) after feeding on silver nanoparticles (nano-Ag) dosed food. The aim of our work was to assess whether feeding on nano-Ag results in the assimilation of silver (Ag) in digestive gland cells. To study micro-localization and elemental distribution of Ag, the animals were fed on food dosed with nanoparticles for 14 days under controlled laboratory conditions. At the end of the feeding exposure, the animals were dissected and digestive glands prepared for micro-PIXE analyses and TEM investigation. The results obtained by micro-PIXE documented high amounts of Ag inside S-cells of the digestive gland epithelium; however, TEM investigation did not show particle aggregates inside digestive gland cells. Also no adverse effect on feeding behavior was recorded what is a measure of toxic effects. We explain the presence of Ag inside the cells as a result of the assimilation of dissoluted Ag ions from ingested nano-Ag particles. Assimilation of excessive amounts of ingested metal ions in S-cells is a well known metal detoxification mechanism in isopods. We discuss the advantages of using micro-PIXE for the micro-localization of elements in biological tissue in studies of interactions between nanoparticles and biological systems.

  11. Micro-PIXE study of Ag in digestive glands of a nano-Ag fed arthropod (Porcellio scaber, Isopoda, Crustacea)

    Energy Technology Data Exchange (ETDEWEB)

    Tkalec, Ziva Pipan [Department of Biology, University of Ljubljana, Vecna pot 111, SI- 1000 Ljubljana (Slovenia); Drobne, Damjana [Department of Biology, University of Ljubljana, Vecna pot 111, SI- 1000 Ljubljana (Slovenia); Centre of Excellence, Advanced Materials and Technologies for the Future (CO NAMASTE), Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Vogel-Mikus, Katarina [Department of Biology, University of Ljubljana, Vecna pot 111, SI- 1000 Ljubljana (Slovenia); Pongrac, Paula [Department of Biology, University of Ljubljana, Vecna pot 111, SI- 1000 Ljubljana (Slovenia); Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Regvar, Marjana; Strus, Jasna [Department of Biology, University of Ljubljana, Vecna pot 111, SI- 1000 Ljubljana (Slovenia); Pelicon, Primoz, E-mail: primoz.pelicon@ijs.si [Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Vavpetic, Primoz; Grlj, Natasa [Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Remskar, Maja [Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Centre of Excellence, Advanced Materials and Technologies for the Future (CO NAMASTE), Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia)

    2011-10-15

    Micro-proton induced X-ray emission (micro-PIXE) method was applied to study the micro-localization of silver (Ag) in digestive glands of a terrestrial arthropod (Porcellio scaber) after feeding on silver nanoparticles (nano-Ag) dosed food. The aim of our work was to assess whether feeding on nano-Ag results in the assimilation of silver (Ag) in digestive gland cells. To study micro-localization and elemental distribution of Ag, the animals were fed on food dosed with nanoparticles for 14 days under controlled laboratory conditions. At the end of the feeding exposure, the animals were dissected and digestive glands prepared for micro-PIXE analyses and TEM investigation. The results obtained by micro-PIXE documented high amounts of Ag inside S-cells of the digestive gland epithelium; however, TEM investigation did not show particle aggregates inside digestive gland cells. Also no adverse effect on feeding behavior was recorded what is a measure of toxic effects. We explain the presence of Ag inside the cells as a result of the assimilation of dissoluted Ag ions from ingested nano-Ag particles. Assimilation of excessive amounts of ingested metal ions in S-cells is a well known metal detoxification mechanism in isopods. We discuss the advantages of using micro-PIXE for the micro-localization of elements in biological tissue in studies of interactions between nanoparticles and biological systems.

  12. Accelerator Mass Spectrometry Analysis of Ultra-Low-Level 129I in Carrier-Free AgI-AgCl Sputter Targets

    DEFF Research Database (Denmark)

    Liu, Qi; Hou, Xiaolin; Zhou, Weijian;

    2015-01-01

    mass spectrometry (AMS) for accurate determination of ultra-low-level 129I in carrier-free AgI-AgCl sputter targets. Copper instead of aluminum was selected as the suitable sample holder material to avoid the reaction of AgI-AgCl powder with aluminum. Niobium powder was selected as thermally...

  13. 11th AG STAB/DGLR Symposium

    CERN Document Server

    Heinemann, Hans-Joachim; Hilbig, Reinhard

    1999-01-01

    This volume contains the papers of the 11th Symposium of the AG STAB (German Aerospace Aerodynamics Association). In this association those scientists and engineers from universities, research-establishments and industry are involved, who are doing research and project work in numerical and experimental fluid mechanics and aerodynamics for aerospace and other applications. Many of the contributions are giving results from the "Luftfahrtforschungsprogramm der Bundesregierung (German Aeronautical Research Programme). Some of the papers report on work sponsored by the Deutsche Forschungsgemeinschaft, DFG, which also was presented at the symposium. The volume gives a broad overview over the ongoing work in this field in Germany.

  14. Magnetic phase diagram of Ho-Ag

    Energy Technology Data Exchange (ETDEWEB)

    Paul-Boncour, V [Chimie Metallurgique des Terres Rares, ICMPE, CNRS, 2 rue H Dunant, 94320 Thiais (France); Hoser, A; Stuesser, N [Hahn-Meitner Institut, Glienicker Strasse 100, 14109, Berlin (Germany); Hense, K; Gratz, E [Institute for Experimental Physics, Technical University Vienna, Wiedner Hauptstrasse 8-10, A-1040 (Austria); Rotter, M [Institut fuer Physikalische Chemie, Universitaet Wien, Waehringerstrasse 42, 1090 Wien (Austria)], E-mail: paulbon@glvt-cnrs.fr

    2008-03-12

    The magnetic phase diagram of Ho-Ag has been established using magnetoresistance, magnetostriction and neutron diffraction experiments versus applied field and temperature. Three different magnetic phases were observed: an incommensurate antiferromagnetic phase (IC) below T{sub N} = 33 K, a commensurate antiferromagnetic phase (C) above 5 T and below T{sub 1} (5-8 K) and a ferromagnetic component above 3 T. The IC phase undergoes spin reorientations around 5 T (IC') and 13 T (IC'')

  15. Modelling of the AGS using Zgoubi - Status

    Energy Technology Data Exchange (ETDEWEB)

    Meot F.; Ahrens, L.; Dutheil, Y.; Glenn, J.; Huang, H.; Roser, T.; Schoefer, V.; Tsoupas, N.

    2012-05-20

    This paper summarizes the progress achieved so far, and discusses various outcomes, regarding the development of a model of the Alternating Gradient Synchrotron at the RHIC collider. The model, based on stepwise ray-tracing methods, includes beam and polarization dynamics. This is an on-going work, and a follow-on of code developments and particle and spin dynamics simulations that have been subject to earlier publications at IPAC and PAC [1, 2, 3]. A companion paper [4] gives additional informations, regarding the use of the measured magnetic field maps of the AGS main magnets.

  16. Three proton hole structure in 106Ag

    Science.gov (United States)

    Das, B.; Rather, N.; Chattopadhyay, S.; Rajbanshi, S.; Goswami, A.; Datta, P.; Roy, S.; Palit, R.; Pal, S.; Saha, S.; Sethi, J.; Biswas, S.; Singh, P.; Jain, H. C.

    2016-06-01

    The negative parity non-yrast band of 106Ag has been studied to investigate the falling trend in magnetic dipole transition rates. In this context, the level lifetimes of the excited levels of this band have been measured using the Doppler shift attenuation method. The comparison of the experimental Routhian and the transition rates with the numerical results of the shears mechanism with the principal axis cranking calculation indicates that this band is generated due to the shears mechanism involving the three proton hole configuration.

  17. Design, construction, system integration, and test results of the 1 MW CW RF system for the e-gun cavity in the energy recovery LINAC at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Lenci,S.J.; Eisen, E. L.; Dickey, D. L.; Sainz, J. E.; Utay, P. F.; Zaltsman, A.; Lambiase, R.

    2009-05-04

    Brookhaven's ERL (Energy Recovery LINAC) requires a 1 MW CW RF system for the superconducting electron gun cavity. The system consists primarily of a klystron tube, transmitter, and High-Voltage Power Supply (HVPS). The 703.75 MHz klystron made by CPl, Inc. provides RF power of 1MW CW with efficiency of 65%. It has a single output window, diode-type electron gun, and collector capable of dissipating the entire beam power. It was fully factory tested including 24-hour heat run at 1.1 MW CWo The solid state HVPS designed by Continental Electronics provides up to 100 kV at low ripple and 2.1 MW CW with over 95% efficiency. With minimal stored energy and a fast shut-down mode no crowbar circuit is needed. Continental 's transmitter includes PLC based user interface and monitoring, RF pre-amplifier, magnet and Vac-Ion pump supplies, cooling water instrumentation, and integral safety interlock system. BNL installed the klystron, HVPS, and transmitter along with other items, such as circulator, water load, and waveguide components. The collaboration of BNL, CPI, and Continental in the design, installation, and testing was essential to the successful operation of the 1MW system.

  18. Comparative Analyses of Brookhaven National Laboratory Nuclear Decay Measurements and Super-Kamiokande Solar Neutrino Measurements: Neutrinos and Neutrino-Induced Beta-Decays as Probes of the Deep Solar Interior

    Science.gov (United States)

    Sturrock, P. A.; Fischbach, E.; Scargle, J. D.

    2016-12-01

    An experiment carried out at the Brookhaven National Laboratory over a period of almost 8 years acquired 364 measurements of the beta-decay rates of a sample of {}^{32}Si and, for comparison, of a sample of {}^{36}Cl. The experimenters reported finding " small periodic annual deviations of the data points from an exponential decay … of uncertain origin". We find that power-spectrum and spectrogram analyses of these datasets show evidence not only of the annual oscillations, but also of transient oscillations with frequencies near 11 year-1 and 12.5 year-1. Similar analyses of 358 measurements of the solar neutrino flux acquired by the Super-Kamiokande neutrino observatory over a period of about 5 years yield evidence of an oscillation near 12.5 year-1 and another near 9.5 year-1. An oscillation near 12.5 year-1 is compatible with the influence of rotation of the radiative zone. We suggest that an oscillation near 9.5 year-1 may be indicative of rotation of the solar core, and that an oscillation near 11 year-1 may have its origin in a tachocline between the core and the radiative zone. Modulation of the solar neutrino flux may be attributed to an influence of the Sun's internal magnetic field by the Resonant Spin Flavor Precession (RSFP) mechanism, suggesting that neutrinos and neutrino-induced beta decays can provide information about the deep solar interior.

  19. The high-temperature modification of LuAgSn and high-pressure high-temperature experiments on DyAgSn, HoAgSn, and YbAgSn

    Energy Technology Data Exchange (ETDEWEB)

    Heying, B.; Rodewald, U.C.; Hermes, W.; Schappacher, F.M.; Riecken, J.F.; Poettgen, R. [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Heymann, G.; Huppertz, H. [Muenchen Univ. (Germany). Dept. fuer Chemie und Biochemie; Sebastian, C.P. [Max-Planck-Institut fuer Chemische Physik Fester Stoffe, Dresden (Germany)

    2008-02-15

    The high-temperature modification of LuAgSn was obtained by arc-melting an equiatomic mixture of the elements followed by quenching the melt on a water-cooled copper crucible. HT-LuAgSn crystallizes with the NdPtSb-type structure, space group P6{sub 3}mc: a = 463.5(1), c = 723.2(1) pm, wR2 = 0.0270, 151 F{sup 2}, and 11 variables. The silver and tin atoms build up two-dimensional, puckered [Ag{sub 3}Sn{sub 3}] networks (276 pm Ag-Sn) that are charge-balanced and separated by the lutetium atoms. The Ag-Sn distances between the [Ag{sub 3}Sn{sub 3}] layers of 294 pm are much longer. Single crystals of isotypic DyAgSn (a = 468.3(1), c = 734.4(1) pm, wR2 = 0.0343, 411 F{sup 2}, and 11 variables) and HoAgSn (a = 467.2(1), c = 731.7(2) pm, wR2 = 0.0318, 330 F{sup 2}, and 11 variables) were obtained from arc-melted samples. Under high-pressure (up to 12.2 GPa) and high-temperature (up to 1470 K) conditions, no transitions to a ZrNiAl-related phase have been observed for DyAgSn, HoAgSn, and YbAgSn. HT-TmAgSn shows Curie-Weiss paramagnetism with {mu}{sub eff} = 7.53(1) {mu}{sub B}/Tm atom and {theta}P = -15.0(5) K. No magnetic ordering was evident down to 3 K. HT-LuAgSn is a Pauli paramagnet. Room-temperature {sup 119}Sn Moessbauer spectra of HT-TmAgSn and HT-LuAgSn show singlet resonances with isomer shifts of 1.78(1) and 1.72(1) mm/s, respectively. (orig.)

  20. The role of reduction extent of graphene oxide in the photocatalytic performance of Ag/AgX (X = Cl, Br)/rGO composites and the pseudo-second-order kinetics reaction nature of the Ag/AgBr system.

    Science.gov (United States)

    Gao, Weiyin; Ran, Chenxin; Wang, Minqiang; Li, Le; Sun, Zhongwang; Yao, Xi

    2016-07-21

    Although reduced graphene oxide (rGO)-based photocatalyst composites have been intensively developed during the past few years, the influence of reduction extent of rGO on the photocatalytic performance of the rGO-based composite has virtually not been investigated due to some technical limitations, such as the poor water dispersibility of rGO and low reduction selectivity of the hydrothermal method, which make it difficult to control the reduction extent of rGO in these composites. Herein, we used a facile room-temperature method to synthesize Ag/AgX (X = Cl, Br)/rGO photocatalyst composites as a model to study the effect of reduction extent of rGO on the photocatalytic performance of the photocatalyst. It was found that the photocatalytic activities of both Ag/AgCl/PrGO and Ag/AgBr/PrGO systems had an optimized threshold of the reduction extent of photoreduced GO (PrGO). More importantly, due to the different conductive band values of AgCl and AgBr, the optimized thresholds in the two systems were at different PrGO reduction extents, based on which we proposed that the favorable energy band matching between AgX and PrGO in the two systems played a crucial role in obtaining high photocatalysis performance. Besides, the photocatalytic reaction of the Ag/AgBr based system was confirmed to be a pseudo-second-order kinetics reaction rather than pseudo-first-order kinetics reaction. The new insights presented in this work provided useful information on the design and development of a more sophisticated photocatalyst, and can also be applied to many other applications.

  1. RRR and thermal conductivity of Ag and Ag0.2wt%Mg alloy in Ag/Bi-2212 wires

    Energy Technology Data Exchange (ETDEWEB)

    Li, Pei [Fermilab; Ye, L. [North Carolina State U.; Jiang. J., Jiang. J. [Natl. High Mag. Field Lab.; Shen, T. [Fermilab

    2015-08-19

    The residual resistivity ratio (RRR) and thermal conductivity of metal matrix in metal/superconductor composite wires are important parameters for designing superconducting magnets. However, the resistivity of silver in reacted Ag/Bi-2212 wires has yet to be determined over temperature range from 4.2 K to 80 K because Bi-2212 filaments have a critical transition temperature Tc of ~ 80 K, and because it is unknown whether the RRR of Ag/Bi-2212 degrades with Cu diffusing from Bi-2212 filaments into silver sheathes at elevated temperatures and to what degree it varies with heat treatment. We measured the resistivity of stand-alone Ag and AgMg (Ag-0.2wt%Mg) wires as well as the resistivity of Ag and Ag- 0.2wt%Mg in the state-of-the-art Ag/Bi-2212 round wires reacted in 1 bar oxygen at 890 °C for 1, 8, 24 and 48 hours and quickly cooled to room temperature. The heat treatment was designed to reduce the critical current Ic of Bi-2212 wires to nearly zero while allowing Cu loss to fully manifest itself. We determined that pure silver exhibits a RRR of ~ 220 while the oxide-dispersion strengthened AgMg exhibits a RRR of ~ 5 in stand-alone samples. A surprising result is that the RRR of silver in the composite round wires doesn’t degrade with extended time at 890 °C for up to 48 hours. This surprising result may be explained by our observation that the Cu that diffuses into the silver tends to form Cu2O precipitates in oxidizing atmosphere, instead of forming Ag-Cu solution alloy. We also measured the thermal conductivity and the magneto-resistivity of pure Ag and Ag-0.2 wt%Mg from 4.2 K to 300 K in magnetic fields up to 14.8 T and summarized them using a Kohler plot.

  2. Properties of Ag+ Ions Alloyed Chalcohalide Glasses in GeS2-Ga2S3-AgI-Ag System

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Jing; YAN; Qiqi; REN; Jing; YANG; Yunxia; CHEN; Guorong

    2015-01-01

    The thermal, physical and optical properties as well as chemical stability of Ag+ alloyed chalcohalide glasses in the Ge S2-Ga2S3-Ag I-Ag system were investigated via the Archimedes method, differential scanning calorimetry, infrared and visible transmission spectroscopy, respectively. The glass composition can be adjusted in a large range without any devitrification. These chalcohalide glasses are optically transparent in both visible and infrared regions. They also have an improved chemical stability in deionized water, compared to other chalcohalide glasses containing halides such as CsI.

  3. Properties of Ag+ Ions Alloyed Chalcohalide Glasses in GeS2-Ga2S3-AgI-Ag System

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing; YAN Qiqi; REN Jing; YANG Yunxia; CHEN Guorong

    2015-01-01

    The thermal, physical and optical properties as well as chemical stability of Ag+ alloyed chalcohalide glasses in the GeS2-Ga2S3-AgI-Ag system were investigatedvia the Archimedes method, differential scanning calorimetry, in-frared and visible transmission spectroscopy, respectively. The glass composition can be adjusted in a large range with-out any devitrification. These chalcohalide glasses are optically transparent in both visible and infrared regions. They also have an improved chemical stability in deionized water, compared to other chalcohalide glasses containing halides such as CsI.

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

    OpenAIRE

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

    2014-01-01

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

  5. Functional analysis of the α-1,3-glucan synthase genes agsA and agsB in Aspergillus nidulans: agsB is the major α-1,3-glucan synthase in this fungus.

    Directory of Open Access Journals (Sweden)

    Akira Yoshimi

    Full Text Available Although α-1,3-glucan is one of the major cell wall polysaccharides in filamentous fungi, the physiological roles of α-1,3-glucan remain unclear. The model fungus Aspergillus nidulans possesses two α-1,3-glucan synthase (AGS genes, agsA and agsB. For functional analysis of these genes, we constructed several mutant strains in A. nidulans: agsA disruption, agsB disruption, and double-disruption strains. We also constructed several CagsB strains in which agsB expression was controlled by the inducible alcA promoter, with or without the agsA-disrupting mutation. The agsA disruption strains did not show markedly different phenotypes from those of the wild-type strain. The agsB disruption strains formed dispersed hyphal cells under liquid culture conditions, regardless of the agsA genetic background. Dispersed hyphal cells were also observed in liquid culture of the CagsB strains when agsB expression was repressed, whereas these strains grew normally in plate culture even under the agsB-repressed conditions. Fractionation of the cell wall based on the alkali solubility of its components, quantification of sugars, and (13C-NMR spectroscopic analysis revealed that α-1,3-glucan was the main component of the alkali-soluble fraction in the wild-type and agsA disruption strains, but almost no α-1,3-glucan was found in the alkali-soluble fraction derived from either the agsB disruption strain or the CagsB strain under the agsB-repressed conditions, regardless of the agsA genetic background. Taken together, our data demonstrate that the two AGS genes are dispensable in A. nidulans, but that AgsB is required for normal growth characteristics under liquid culture conditions and is the major AGS in this species.

  6. Functional analysis of the α-1,3-glucan synthase genes agsA and agsB in Aspergillus nidulans: agsB is the major α-1,3-glucan synthase in this fungus.

    Science.gov (United States)

    Yoshimi, Akira; Sano, Motoaki; Inaba, Azusa; Kokubun, Yuko; Fujioka, Tomonori; Mizutani, Osamu; Hagiwara, Daisuke; Fujikawa, Takashi; Nishimura, Marie; Yano, Shigekazu; Kasahara, Shin; Shimizu, Kiminori; Yamaguchi, Masashi; Kawakami, Kazuyoshi; Abe, Keietsu

    2013-01-01

    Although α-1,3-glucan is one of the major cell wall polysaccharides in filamentous fungi, the physiological roles of α-1,3-glucan remain unclear. The model fungus Aspergillus nidulans possesses two α-1,3-glucan synthase (AGS) genes, agsA and agsB. For functional analysis of these genes, we constructed several mutant strains in A. nidulans: agsA disruption, agsB disruption, and double-disruption strains. We also constructed several CagsB strains in which agsB expression was controlled by the inducible alcA promoter, with or without the agsA-disrupting mutation. The agsA disruption strains did not show markedly different phenotypes from those of the wild-type strain. The agsB disruption strains formed dispersed hyphal cells under liquid culture conditions, regardless of the agsA genetic background. Dispersed hyphal cells were also observed in liquid culture of the CagsB strains when agsB expression was repressed, whereas these strains grew normally in plate culture even under the agsB-repressed conditions. Fractionation of the cell wall based on the alkali solubility of its components, quantification of sugars, and (13)C-NMR spectroscopic analysis revealed that α-1,3-glucan was the main component of the alkali-soluble fraction in the wild-type and agsA disruption strains, but almost no α-1,3-glucan was found in the alkali-soluble fraction derived from either the agsB disruption strain or the CagsB strain under the agsB-repressed conditions, regardless of the agsA genetic background. Taken together, our data demonstrate that the two AGS genes are dispensable in A. nidulans, but that AgsB is required for normal growth characteristics under liquid culture conditions and is the major AGS in this species.

  7. Microwave-assisted solvothermal synthesis of flower-like Ag/AgBr/BiOBr microspheres and their high efficient photocatalytic degradation for p-nitrophenol

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tingting, E-mail: tingtingli1983@hotmail.com [Department of Chemistry and Chemical Engineering, Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Changsha 410082 (China); State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Department of Environment and Chemical Engineering, Key Laboratory of Jiangxi Province for Ecological Diagnosis, Remediation and Pollution Control, Nanchang Hangkong University, Nanchang 330063 (China); Luo, Shenglian, E-mail: sllou@hnu.edu.cn [Department of Chemistry and Chemical Engineering, Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Changsha 410082 (China); State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Department of Environment and Chemical Engineering, Key Laboratory of Jiangxi Province for Ecological Diagnosis, Remediation and Pollution Control, Nanchang Hangkong University, Nanchang 330063 (China); Yang, Lixia [Department of Environment and Chemical Engineering, Key Laboratory of Jiangxi Province for Ecological Diagnosis, Remediation and Pollution Control, Nanchang Hangkong University, Nanchang 330063 (China)

    2013-10-15

    Flower-like Ag/AgBr/BiOBr microspheres were successfully fabricated by the approach of microwave-assisted solvothermal and in situ photo-assisted reduction. A reactive ionic liquid 1-hexadecyl-3-methylimidazolium bromide ([C{sub 16}mim]Br) was employed as Br source in the presence of surfactant polyvinylpyrrolidone (PVP). The photocatalytic activity of Ag/AgBr/BiOBr towards the decomposition of p-nitrophenol under visible light irradiation was evaluated. The results indicated that Ag/AgBr/BiOBr showed enhanced photocatalytic activity towards p-nitrophenol, comparing with P25, BiOBr and Ag/AgBr. More than 96% of p-nitrophenol was decomposed in 3.5 h under visible-light irradation. The excellent photocatalytic activity of flower-like Ag/AgBr/BiOBr microspheres can be attributed to the large specific surface area, strong visible-light absorption, suitable energy band structure and surface plasmon resonance effect of Ag nanoparticles. The possible photocatalytic mechanism was proposed based on the active species test and band gap structure analysis. - Graphical abstract: The photocatalytic reaction mechanisms of the as-prepared Ag/AgBr/BiOBr. Display Omitted - Highlights: • Successful synthesis of flower-like Ag/AgBr/BiOBr microspheres. • The Ag/AgBr/BiOBr showed much higher photocatalytic activity towards p-nitrophenol as compared to BiOBr and Ag/AgBr. • The reasons for the excellent photocatalytic activity are the large specific surface area, strong visible-light absorption and surface plasmon resonance effect of Ag nanoparticles. • The O{sub 2}·{sup −}, Br{sup 0} and photogenerated h{sup +} play key roles in the photocatalytic degradation process.

  8. Synthesis, characterization and optical properties of low nuclearity liganded silver clusters: Ag31(SG)19 and Ag15(SG)11

    Science.gov (United States)

    Bertorelle, Franck; Hamouda, Ramzi; Rayane, Driss; Broyer, Michel; Antoine, Rodolphe; Dugourd, Philippe; Gell, Lars; Kulesza, Alexander; MitrićPresent Address: Institut Für Physikalische Und Theoretische Chemie, Julius-Maximilians Universität Würzburg, Emil-Fischer-Straße 42, 97074 Würzburg, Germany, Roland; Bonačić-Koutecký, Vlasta

    2013-05-01

    We report a simple synthesis of silver:glutathione (Ag:SG) clusters using a cyclic reduction under oxidative conditions. Two syntheses are described which lead to solutions containing well-defined Ag31(SG)19 and Ag15(SG)11 clusters that have been characterized by mass spectrometry. The optical properties of silver:glutathione (Ag:SG) cluster solutions have been investigated experimentally. In particular, the solution containing Ag15(SG)11 clusters shows a bright and photostable emission. For Ag31(SG)19 and Ag15(SG)11 clusters, the comparison of experimental findings with DFT and TDDFT calculations allowed us to reveal the structural and electronic properties of such low nuclearity liganded silver clusters.We report a simple synthesis of silver:glutathione (Ag:SG) clusters using a cyclic reduction under oxidative conditions. Two syntheses are described which lead to solutions containing well-defined Ag31(SG)19 and Ag15(SG)11 clusters that have been characterized by mass spectrometry. The optical properties of silver:glutathione (Ag:SG) cluster solutions have been investigated experimentally. In particular, the solution containing Ag15(SG)11 clusters shows a bright and photostable emission. For Ag31(SG)19 and Ag15(SG)11 clusters, the comparison of experimental findings with DFT and TDDFT calculations allowed us to reveal the structural and electronic properties of such low nuclearity liganded silver clusters. Electronic supplementary information (ESI) available: Optimal settings for the MS instrument; schematic diagrams for syntheses A and B; ESI mass spectra of silver clusters from ``synthesis A'' in different solvent mixtures, at different pH values and with different synthesis protocols; excitation and emission spectra of clusters from ``synthesis B'' in water and of the separated band after PAGE separation; lifetime measurements of silver clusters from a solution of ``synthesis B'' in water; the structure and absorption spectrum of the two lowest-energy isomers

  9. Strategic Risk Management and it applications to Porsche AG

    OpenAIRE

    Oláh, Róbert

    2009-01-01

    The main objective of this thesis is not only to describe and categorize risk but also to look at Porsche AG and determine how they deal with strategic risks. Primary focus is on the description and categorization of risks, strategic risks, importance of Risk Management and strategic risks faced by Porsche AG and their mitigation.

  10. AGS vertical beta function measurements for Run 15

    Energy Technology Data Exchange (ETDEWEB)

    Harper, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ahrens, L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Schoefer, V. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-10-07

    One key parameter for running the AGS efficiently is by maintaining a low emittance. To measure emittance, one needs to measure the beta function throughout the cycle. This can be done by measuring the beta function at the ionization profile monitors (IPM) in the AGS. This tech note delves into the motivation, the measurement, and some strides that were made throughout Run15.

  11. Antibacterial activities of PHU - AgNO{sub 3} nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Panzaru, Carmen; Danciu, M; Mihailovici, Maria-Sultana [' Gr.T.Popa' University of Medicine and Pharmacy, Iasi (Romania)], E-mail: carmenpanzaru@yahoo.com; Ciobanu, C [' Petru Poni' Institute of Macromolecular Chemistry, Iasi (Romania)

    2009-05-01

    Objective was to characterize the antibacterial action for six combination of PHU-AgNO{sub 3} synthesized in 'Petru Poni' Institute of Macromolecular Chemistry, Iasi, Romania. The advantages of Ag nanoparticles are durability, heat resistant, low toxicity. Silver is known for its antibacterial qualities for a long time and has been used in medicine in topical treatment.

  12. Conduction Band of the Photographic Compound AgCl

    NARCIS (Netherlands)

    Boer, P.K. de; Groot, R.A. de

    1999-01-01

    Electronic structure calculations on the photographic compound AgCl are reported. It is shown that the conduction band has a large Cl-4s character, contrary to the common picture of the conduction band being derived from Ag-5s states. Possible consequences for the photographic process are discussed.

  13. Study of Ag and PE interface after plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Mackova, A.; Malinsky, P. [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske mladeze 8, 400 96 Usti nad Labem (Czech Republic); Bocan, J. [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, 250 68 Rez (Czech Republic); Department of Physics, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Brehova 7, 11519 Praha 1 (Czech Republic); Svorcik, V. [Department of Solid State Engineering, Institute of Chemical Technology, Technicka 5, 166 28 Prague (Czech Republic); Pavlik, J.; Stryhal, Z. [Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske mladeze 8, 400 96 Usti nad Labem (Czech Republic); Sajdl, P. [Department of Inorganic Chemistry, Institute of Chemical Technology, Technicka 5,166 28 Prague (Czech Republic)

    2008-07-01

    In this study, the effect of simultaneous plasma treatment and thermal annealing on the diffusion of Ag in low and high-density polyethylene (LDPE and HDPE) and on intermixing at the metal/polymer interface is examined. Metal layers were deposited onto 50 {mu}m thick LDPE and HDPE foils using diode sputtering. Concentration profiles of Ag were determined by Rutherford backscattering spectrometry (RBS). Ag diffusion coefficients in LDPE and HDPE were extracted from measured Ag depth profiles. Diffusion coefficients 5.05 x 10{sup -14}-6.78 x 10{sup -14} cm{sup 2}.s{sup -1} and 2.44 x 10{sup -14}-4.66 x 10{sup -14} cm{sup 2}.s{sup -1} were found for Ag in HDPE and Ag in LDPE, respectively. Morphology changes after the plasma treatment were determined using atomic force microscopy (AFM) and from RBS measurements as well. Surface fraction of Ag and plasma induced surface chemistry modification was investigated using XPS analysis. The signal of Ag bonded on polymer structure was identified and degradation of polymer substrate was observed in XPS spectra. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Coupling of Er ions to surface plasmons on Ag

    NARCIS (Netherlands)

    Kalkman, J.; Kuipers, L.; Gersen, H.; Polman, A.

    2005-01-01

    Er3+ ions located 100 nm beneath the surface of silica glass show an enhanced photoluminescence decay rate when the glass is covered with Ag. Correcting for concentration quenching effects, the decay rate is enhanced by 70%, compared to the case without Ag. The data are in agreement with a model th

  15. Quantification of HBsAg: basic virology for clinical practice.

    Science.gov (United States)

    Lee, Jung Min; Ahn, Sang Hoon

    2011-01-21

    Hepatitis B surface antigen (HBsAg) is produced and secreted through a complex mechanism that is still not fully understood. In clinical fields, HBsAg has long served as a qualitative diagnostic marker for hepatitis B virus infection. Notably, advances have been made in the development of quantitative HBsAg assays, which have allowed viral replication monitoring, and there is an opportunity to make maximal use of quantitative HBsAg to elucidate its role in clinical fields. Yet, it needs to be underscored that a further understanding of HBsAg, not only from clinical point of view but also from a virologic point of view, would enable us to deepen our insights, so that we could more widely expand and apply its utility. It is also important to be familiar with HBsAg variants and their clinical consequences in terms of immune escape mutants, issues resulting from overlap with corresponding mutation in the P gene, and detection problems for the HBsAg variants. In this article, we review current concepts and issues on the quantification of HBsAg titers with respect to their biologic nature, method principles, and clinically relevant topics.

  16. Microstructure and optical properties of nano Ag-ITO films

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Nano Ag-ITO films with Ag volume fraction of 0.3%-1.0% were prepared by radio-frequency magnetron co-sputtering and analyzed by X-ray diffraction,scanning electron microscopy and ultraviolet-visible spectroscopy.Microstructure analysis shows that the films are composed of polycrystalline ITO matrix embedded with Ag nanoparticles with a mean size of 60-100 nm.Transmissivity spectra of Ag-ITO films indicate that the visible light transmissivity of the films decreases with increasing the Ag fraction.The transmissivity of the annealed films is higher than that of the as-deposited films.The volume 0.3% Ag-ITO films have the highest light reflectance.The annealed films exhibit lower light absorptance than as-deposited films.A surface plasmon resonance(SPR) peak of volume 0.3% Ag-ITO films is located around 510 nm.Compared with the annealed ITO film,the annealed volume 0.3% Ag-ITO film shows 10% higher reflectivity,while its transmittance is almost the same as that of the annealed ITO film,indicating its potential application in new-type transflective displays.

  17. Early invasive prenatal diagnosis in HBsAg-positive women

    NARCIS (Netherlands)

    P.M. Grosheide (Pia Maria); H.W.P. Quartero (H. W P); S.W. Schalm (Solko); R.A. Heijtink; C.G.M.L. Christiaens

    1994-01-01

    textabstractFrom 1982 to 1989, pregnant women in two large city hospitals in The Netherlands had serum samples screened for hepatitis B surface antigen (HBsAg). Infants of mothers found to be HBsAg-positive received hepatitis B immune globulin immediately after birth and hepatitis B vaccine in the f

  18. Laser Direct Writing of Ag Films from Solution on Si Substrate

    Institute of Scientific and Technical Information of China (English)

    Ke SUN; Caibei ZHANG; Yan ZHAO

    2003-01-01

    Pulsed Nd:YAG laser was used to irradiate Si substrate immersed in AgNO3 ethylene glycol solution to deposit Ag films along the lines scanned by laser on the substrate, which is a photo-thermal decomposing process. The decomposed Ag atoms congregate and form polycrystalline Ag particles. The Ag concentration changes greatly with the total laser energy4absorbed by substrate. Transmission electron microscopy (TEM) observation shows the Ag particles are inlaid in the Si substrate. Auger electron spectrum (AES) shows that the Ag concentration decreases with the increase of the sputtering depth, and there is no oxygen element on the surface of the deposited Ag films.

  19. Fabrication of graphene oxide enwrapped Z-scheme Ag2SO3/AgBr nanoparticles with enhanced visible-light photocatalysis

    Science.gov (United States)

    Wan, Yujuan; Liang, Chunyan; Xia, Yue; Huang, Wei; Li, Zelin

    2017-02-01

    A novel graphene oxide (GO) enwrapped Ag2SO3/AgBr (GO/Ag2SO3/AgBr) composite was fabricated through a facile solution approach via electrostatic interaction and precipitation transformation reaction for the first time. The results of XRD, Raman, SEM, TEM and XPS confirmed the structure, morphology and composition of the GO/Ag2SO3/AgBr composite very well. The Ag2SO3/AgBr nanoparticles were found to be encapsulated by GO sheets. The photocatalytic activity of the composite was investigated by the degradation of methyl orange (MO), rhodamine B (RhB) and methylene blue (MB) in water under visible light. The incorporation of GO sheets not only significantly enhanced the photocatalytic activity but also improved the reusability of Ag2SO3/AgBr nanoparticles. The photocatalytic ability of GO/Ag2SO3/AgBr can be maintained at a high level for 4 times cycle experiments. The trapping experiments confirmed that holes and superoxide ion radicals were the main active species responsible for the degradation reaction. A plasmonic Z-scheme photocatalytic mechanism was proposed to illustrate the possible transferred and separated behavior of electron-hole pairs among Ag, Ag2SO3, AgBr and GO quaternary system under visible light irradiation.

  20. Embedment of nano-sized Ag layer into Ag-doped In2O3 films for use as highly transparent and conductive anode in organic solar cells

    Science.gov (United States)

    Cho, Da-Young; Na, Seok-In; Chung, Kwun-Bum; Kim, Han-Ki

    2015-08-01

    By inserting a nano-sized Ag layer between bottom Ag-doped In2O3 (AIO) and a top AIO layer, we were able to control the sheet resistance and optical transmittance of AIO films for application in organic solar cells (OSCs) as a transparent electrode. To optimize the AIO/Ag/AIO multilayer, we investigated the electrical, optical, structural and morphological properties of the AIO/Ag/AIO multilayer as a function of Ag interlayer thickness with a constant bottom and top AIO thickness of 35 nm. The optimized AIO/Ag/AIO multilayer showed a much lower resistivity of 3.988 × 10-5 Ω cm and a higher optical transmittance of 84.79% than the values (4.625 × 10-4 Ω cm and 78.36%) of the single AIO film, due to the high conductivity of the metallic Ag layer and the antireflection effect of the symmetric AIO/Ag/AIO structure. In addition, we investigated the performances of OSCs with AIO/Ag/AIO electrodes as a function of Ag interlayer thickness to determine the optimal Ag thickness to produce a high power conversion efficiency (PCE) of the OSCs. Based on the PCE of the OSCs, we correlated the performance of the OSCs with the Ag interlayer thickness in the AIO/Ag/AIO multilayer and suggested a possible mechanism to explain the dependency of PCE on Ag thickness in AIO/Ag/AIO multilayer electrodes.

  1. Underlayer Roughness Influence on the Properties of ag Thin Film

    Science.gov (United States)

    Zhao, Pei; Wang, Reng; Liu, Dingquan; Zhang, Fengshan; Su, Weitao; Xu, Xiaofeng

    The effects of the roughness of ZnS underlayer on the microstructure, optical, and electrical properties of nanometer Ag thin film have been investigated in this paper. Nanometer Ag thin films in glass/ZnS/7.5 nm Ag/30 nm ZnS stacks have been deposited and analyzed. In the stacks, the underlayers of ZnS have been sputtered with various thicknesses to generate various surface roughnesses. The X-ray diffraction (XRD) has been used to study the crystal structure of Ag films. The surface topography and the roughness of ZnS underlayer have been analyzed by atomic force microscopy. The sheet resistant will become larger as the increasing of the roughness. The optical constants can be derived by fitting the transmission and reflectance spectrum. From optical constants comparison of Ag films, with the surface of the stack becoming rougher, it was found that the refractive index will increase but the extinction coefficient will decrease.

  2. Synthesis of Ag@Silica Nanoparticles by Assisted Laser Ablation

    Science.gov (United States)

    González-Castillo, Jr.; Rodriguez, E.; Jimenez-Villar, E.; Rodríguez, D.; Salomon-García, I.; de Sá, Gilberto F.; García-Fernández, T.; Almeida, DB; Cesar, CL; Johnes, R.; Ibarra, Juana C.

    2015-10-01

    This paper reports the synthesis of silver nanoparticles coated with porous silica (Ag@Silica NPs) using an assisted laser ablation method. This method is a chemical synthesis where one of the reagents (the reducer agent) is introduced in nanometer form by laser ablation of a solid target submerged in an aqueous solution. In a first step, a silicon wafer immersed in water solution was laser ablated for several minutes. Subsequently, an AgNO3 aliquot was added to the aqueous solution. The redox reaction between the silver ions and ablation products leads to a colloidal suspension of core-shell Ag@Silica NPs. The influence of the laser pulse energy, laser wavelength, ablation time, and Ag+ concentration on the size and optical properties of the Ag@Silica NPs was investigated. Furthermore, the colloidal suspensions were studied by UV-VIS-NIR spectroscopy, X-Ray diffraction, and high-resolution transmission electron microscopy (HRTEM).

  3. Antifungal Applications of Ag-Decorated Hydroxyapatite Nanoparticles

    Directory of Open Access Journals (Sweden)

    C. A. Zamperini

    2013-01-01

    Full Text Available Pure hydroxyapatite (HA and hydroxyapatite decorated with silver (HA@Ag nanoparticles were synthesized and characterized. The antifungal effect of HA@Ag nanoparticles in a distilled water solution was evaluated against Candida albicans. The origin of the antifungal activity of the HA@Ag is also discussed. The results obtained showed that the HA nanorod morphology remained the same with Ag ions decorations on the HA structure which were deposited in the form of nanospheres. Interaction where occurred between the structure and its defect density variation in the interfacial HA@Ag and intrafacial HA region with the fungal medium resulted in antifungal activity. The reaction mechanisms involved oxygen and water adsorption which formed an active complex cluster. The decomposition and desorption of the final products as well as the electron/hole recombination process have an important role in fungicidal effects.

  4. Preparation and Activity of Photocatalytic Composite Ag-AgCl/Graphene%复合光催化材料Ag-AgCl/石墨烯的制备及性能

    Institute of Scientific and Technical Information of China (English)

    褚亮亮; 董斌; 周建伟; 王储备

    2013-01-01

    以原位化学沉淀-光还原法制备了Ag-AgCl/石墨烯复合光催化材料.以罗丹明B为模型降解物,研究了其可见光催化性能.实验结果表明:石墨烯的引入使Ag-AgCl/石墨烯催化剂催化活性提高;当初始罗丹明B质量浓度为5 mg/L时,可见光照射60 min后罗丹明B的降解率可达99%;降解率随初始罗丹明B质量浓度的增加而减小.Ag-AgCl/石墨烯具有很高的可见光催化活性和稳定性.%Abstacrt:The photocatalytic composite Ag-AgCl/grapheme was prepared by in-situ chemical precipitation-photoreduction method and its visible-light photocatalytic activity was studied using Rhodamine B as degradation substrate.The experimental results show that:The catalytic activity of the catalyst is improved with the introduction of grapheme; When the initial mass concentration of Rhodamine B is 5 mg/L,its degradation rate can reach 99% after 60 min of visible-light irradiation; The degradation rate is decreased with the increasing of the initial mass concentration of Rhodamine B.The visible-light photocatalytic activity and stability of Ag-AgCl/grapheme are high.

  5. Screening different Brassica spp. germplasm for resistance to Rhizoctonia solani AG-2-1 and AG-8

    Science.gov (United States)

    Poor stands of canola seedlings in Pacific Northwest (PNW) have been associated with Rhizoctonia solani AG-2-1 and AG-8. A total of eighty five genotypes of Brassica napus, B. rapa, B. carinata, B. juncea and Sinapsis alba were evaluated in the growth chamber for their resistance to both R. solani A...

  6. Difference in hTERT Gene Expressions between HbsAg-Positive and HbsAg-Negative Hepatocellular Carcinoma

    Institute of Scientific and Technical Information of China (English)

    GUO Yueqing; ZHOU Xu; LIU Enyu; LI Xingrui; LIU Jinwen; YANG Zhifang; YI Jilin

    2005-01-01

    Summary: To investigate the difference in expression of hTERT gene between HbsAg-positive human hepatocellular carcinoma (HCC) and HbsAg-negative HCC and to explore the relationship between HBV infection and hTERT gene expression in HCC. The expression of hTERT protein in 30 cases of HbsAg positive HCC and 17 cases of HbsAg negative HCC was detected by immunohistochemistry (SP method), and the expression of hTERT mRNA was analyzed by reverse transcription polymerase chain reaction (RT-PCR). t-test, Chi-squared test and cochran- armitage trend test were used to see whether there was an interrelation between HBsAg and hTERT gene in HCC. The expression of hTERT protein was mostly located in plasm and occasionally in the nucleus of liver cancer cells. The positive rate of hTERT protein and hTERT mRNA in HbsAg positive HCC- 93.33 % (28/30) and 83.33 % (25/30) respectively which were much higher than those in HbsAg negative HCC- 52.94 % (9/17), 47.06 % (8/17) (P<0.01) respectively. HbsAg is related to hTERT gene expression in human hepatocellular carcinoma. The hTERT gene activated by the efficacious ingredient of HBV may play an important role in hepatocellular transformation and carcinogenesis.

  7. Dissociation energies of AgRG (RG = Ar, Kr, Xe) and AgO molecules from velocity map imaging studies

    CERN Document Server

    Cooper, Graham A; Gentleman, Alexander S; Iskra, Andreas; van Wijk, Robert; Mackenzie, Stuart R

    2015-01-01

    The near ultraviolet photodissociation dynamics of silver atom rare gas dimers have been studied by velocity map imaging. AgRG (RG = Ar, Kr, Xe) species generated by laser ablation are excited in the region of the C <- X continuum leading to direct, near threshold dissociation generating Ag* (2P3/2) + RG (1S0) products. Images recorded at excitation wavelengths throughout the C <- X continuum, coupled with known atomic energy levels, permit determination of the ground X (2SIGMA+) state dissociation energies of 85.9 +/- 23.4 cm-1 (AgAr), 149.3 +/- 22.4 cm-1 (AgKr) and 256.3 +/- 16.0 cm-1 (AgXe). Three additional photolysis processes, each yielding Ag atom photoproducts, are observed in the same spectral region. Two of these are markedly enhanced in intensity upon seeding the molecular beam with nitrous oxide, and are assigned to photodissociation of AgO at the two photon level. These features yield an improved ground state dissociation energy for AgO of 15965 +/- 81 cm-1, which is in good agreement with ...

  8. The large 1 1Ag - 2 1Ag C=C stretching vibronic interaction in all-trans polyenes

    NARCIS (Netherlands)

    Buma, W.J.; Zerbetto, F.

    1998-01-01

    An ab initio theoretical approach at several levels of theory is employed to calculate the 11Ag--21Ag- (non)adiabatic vibronic couplings induced by the completely in-phase C=C and C-C bond stretching vibrations of five all-trans polyenes (from butadiene to dodecahexaene). The nonadiabatic couplings

  9. Recyclable and visible light sensitive Ag-AgBr/TiO2: Surface adsorption and photodegradation of MO

    Science.gov (United States)

    Liu, Xinxin; Zhang, Dong; Guo, Biao; Qu, Yue; Tian, Ge; Yue, Huijuan; Feng, Shouhua

    2015-10-01

    A range of highly efficient nanoheterojunction structured Ag-AgBr/TiO2 photocatalysts have been synthesized by CTAB-assisted method and characterized by X-ray diffraction (XRD), focused ion beam scanning electron microscopy (FIB-SEM), energy-dispersive spectroscopy (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL). The results demonstrated that Ag-AgBr nanoparticles were successfully deposited on the surface of anatase TiO2 hierarchical spheres. The remarkable adsorptive removal of methyl orange (MO) by the uncalcined samples was investigated before evaluating its photocatalytic ability. All the calcined three-component catalysts possessed excellent photocatalytic activities for degrading MO under visible light, in which, 162.4% Ag-AgBr/TiO2 exhibited highest efficiency. The greatly enhanced activity can be attributed to the well combination of surface plasmons photocatalyst Ag-AgBr and TiO2, which can simultaneously inhibit the photo-generated electrons and holes recombination. The nanoheterojunctions architecture catalyst also showed high stability even after five consecutive cycles. Meanwhile, the possible mechanism and interpretation of the photocatalytic process were also proposed.

  10. Highly sensitive and selective electrochemical determination of dopamine and ascorbic acid at Ag/Ag{sub 2}S modified electrode

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chen-Yan [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Cai, Ying-Jie [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Yang, Chien-Hsin [Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung 81148, Taiwan (China); Wu, Chen-Hao [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Wei, Yen [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Department of Chemistry, Drexel University, Philadelphia, PA 19104 (United States); Wen, Ten-Chin, E-mail: tcwen@mail.ncku.edu.t [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Wang, Tzong-Liu; Shieh, Yeong-Tarng [Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung 81148, Taiwan (China); Lin, Wen-Churng [Department of Environmental Engineering, Kun Shan University, Tainan 71016, Taiwan (China); Chen, Wen-Janq [Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung 81148, Taiwan (China)

    2011-02-01

    A biosensor electrode possessing highly sensitive and selective determination of dopamine (DA) is fabricated. This electrode, a silver (Ag) thin film on indium-tin-oxide glass, is treated with a silver sulfide (Ag{sub 2}S) film using electrochemical deposition. Active Ag ion is easier to form on Ag{sub 2}S than on pristine Ag, which prefers to attract ascorbic acid (AA). The Ag{sub 2}S layer reduces the oxidation potential of AA due to the electrostatic interaction, which results in well-separation of mixed oxidation responses to both of DA and AA. Besides, the Ag{sub 2}S-modified electrode exhibits dramatic electrocatalytic effect on the oxidation of DA in the presence of AA. In 0.1 M phosphate buffer solution at pH {approx} 7.0, the differential pulse voltammetric peak intensity linearly correlates with DA concentration in two regions, viz. 1.0-10, and 10-100 {mu}M, with correlation coefficient of 0.998 and 0.995, respectively. The lowest concentration limit of 1.0 {mu}M DA can be detected. The interference of AA effectively diminishes in the mixed solution. These features make the Ag{sub 2}S significant for selective and sensitive measurement of DA in the presence of excess AA.

  11. Durable antibacterial Ag/polyacrylonitrile (Ag/PAN) hybrid nanofibers prepared by atmospheric plasma treatment and electrospinning

    Science.gov (United States)

    Durable antibacterial Ag/polyacrylonitrile (Ag/PAN) hybrid nanofibers were prepared by atmospheric plasma treatment and electrospinning. Atmospheric helium plasma treatment was first used to reduce the silver nitrate precursor in pre-electrospinning solutions into metallic silver nanoparticles, foll...

  12. Nano Ag@AgBr surface-sensitized Bi2WO6 photocatalyst: oil-in-water synthesis and enhanced photocatalytic degradation

    Science.gov (United States)

    Lin, Shuanglong; Liu, Li; Hu, Jinshan; Liang, Yinghua; Cui, Wenquan

    2015-01-01

    Nano Ag@AgBr decorated on the surface of flower-like Bi2WO6 (hereafter designated Ag@AgBr/Bi2WO6) were prepared via a facile oil-in-water self-assembly method. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS), etc. The characterization results indicated that nano Ag@AgBr was observed to be evenly dispersed on the surface of Bi2WO6, and was approximately 20 nm in size. Ag@AgBr/Bi2WO6 composites exhibited excellent UV-vis absorption, due to quantum dimension effect of Ag@AgBr, the surface plasmonic resonance (SPR) of Ag nanoparticles and the special flower-like structure of Bi2WO6. The photoelectrochemical measurement verified that the suitable band potential of Ag@AgBr and Bi2WO6 and the existence of metal Ag resulted in the high efficiency in charge separation of the composite. The photocatalytic activities of the Ag@AgBr/Bi2WO6 samples were examined under visible-light irradiation for the degradation of methylene blue (MB). The composite presented excellent photocatalytic activity due to the synergetic effect of Bi2WO6, AgBr, and Ag nanoparticles. The Ag@AgBr(20 wt.%)/Bi2WO6 sample exhibited the best photocatalytic activity, degrading 95.03% MB after irradiation for 2 h, which was respectively 1.29 times and 1.28 times higher than that of Ag@AgBr and Bi2WO6 photocatalyst. Meanwhile, phenol and salicylic acid were degraded to further prove the degradation ability of Ag@AgBr/Bi2WO6. Additionally, studies performed using radical scavengers indicated that O2-•, •OH and Br0 acted as the main reactive species. Based on above, a photocatalytic mechanism for organics degradation over Ag@AgBr/Bi2WO6 was proposed.

  13. Study of Ag and Au Nanoparticles Synthesized by Arc Discharge in Deionized Water

    Directory of Open Access Journals (Sweden)

    Der-Chi Tien

    2010-01-01

    Full Text Available The paper presents a study of Ag and Au nanofluids synthesized by the arc discharge method (ADM in deionized water. The metallic Ag nanoparticle (Ag0 and ionic Ag (Ag+ have played an important role in the battle against germs which are becoming more drug-resistant every year. Our study indicates that Ag nanoparticle suspension (SNPS fabricated by using ADM without added surfactants exclusively contains the metallic Ag nanoparticle and ionic Ag. Besides that, the ADM in deionized water has also been employed for the fabrication process of Au nanoparticles. The experimental results indicate that the prepared Ag nanoparticles can react with the dissolved H2CO3 in deionized water, leading to the formation of Ag2CO3. Significantly different to Ag, the prepared Au nanoparticles with their surfaces bonded by oxygen are suspended in deionized water by the formation of hydrogen bonded with the neighboring water molecules.

  14. The study on interfacial bonding strength of Ag-Ni, Ag-Cu in cold pressure welding

    Institute of Scientific and Technical Information of China (English)

    李云涛; 杜则裕; 陈丽萍

    2003-01-01

    The area of combination actually is a kind of interfacial phenomena that exist on the surface or thin film. The properties of interface have important effect on the whole welded joint, even decide directly the interfacial bonding strength. The bonding strength of metals in cold pressure welding such as Ag-Ni (they are hardly mutual soluble) and Ag-Cu(they are limited soluble) are discussed in this paper. The results of the tensile test suggest that two kinds of welded joints have enough strength to satisfy with the demand for being used. Moreover, thermodynamics, crystal logy, physics and metal electronic microscopic analysis etc are adopted to further calculate the bonding strength. The results of test and theoretical analyses prove that Ag-Ni, Ag-Cu, especially, for Ag-Ni can form strong welded joint which is higher than that of the relative soft base metals in cold pressure welding.

  15. Microwave switching behaviors of Fe/Ag/Fe/Ag epitaxial films

    Energy Technology Data Exchange (ETDEWEB)

    Hung, D.-S. [Department of Information and Telecommunications Engineering, Ming Chuan University, Taipei, Taiwan (China)]. E-mail: dshung@mcu.edu.tw; Tsai, C.S. [Department of Electrical and Computer Engineering, University of California, Irvine, CA (United States); Yu, C.-C. [Institute of Physics, Academia Sinica, Taipei, Taiwan (China); Liou, Y. [Institute of Physics, Academia Sinica, Taipei, Taiwan (China); Lee, Shang-Fan [Institute of Physics, Academia Sinica, Taipei, Taiwan (China); Chiang, P.-C. [Department of Chemical Engineering, Tunghai University, Taichung, Taiwan (China); Ho, C.-S. [Department of Chemical Engineering, Tunghai University, Taichung, Taiwan (China); Yao, Y.-D. [Institute of Physics, Academia Sinica, Taipei, Taiwan (China)

    2006-09-15

    In this study, Fe/Ag/Fe/Ag ferromagnetic structures were epitaxially grown on a GaAs(1 0 0) substrate. Using the Network Analyzer (Agilent 8510C), FMR (ferromagnetic resonant) signals were observed in samples as the in-plane magnetic field was applied to either hard- or easy-axes. Of interest was that our sample demonstrated a FMR-switching behavior in hard-axis but not in easy-axis. The detecting data showed that the switch magnetic field was much smaller than what has been stated previously in Fe/Cu/Fe systems by other laboratories. In addition to the frequency switch in FMR, we also observed a magnetic reversal behavior in its M-H curve. Data presented that both of the FMR and magnetic reverse took place in the same direction (hard-axis)

  16. AgSbSe{sub 2} and AgSb(S,Se){sub 2} thin films for photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Garza, J.G. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Shaji, S. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Facultad de Ingenieria Mecanica y Electrica, CIIDIT - Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico); Rodriguez, A.C.; Das Roy, T.K. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Krishnan, B., E-mail: kbindu_k@yahoo.com [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Facultad de Ingenieria Mecanica y Electrica, CIIDIT - Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico)

    2011-10-01

    Silver antimony selenide (AgSbSe{sub 2}) thin films were prepared by heating sequentially deposited multilayers of antimony sulphide (Sb{sub 2}S{sub 3}), silver selenide (Ag{sub 2}Se), selenium (Se) and silver (Ag). Sb{sub 2}S{sub 3} thin film was prepared from a chemical bath containing SbCl{sub 3} and Na{sub 2}S{sub 2}O{sub 3}, Ag{sub 2}Se from a solution containing AgNO{sub 3} and Na{sub 2}SeSO{sub 3} and Se thin films from an acidified solution of Na{sub 2}SeSO{sub 3}, at room temperature on glass substrates. Ag thin film was deposited by thermal evaporation. The annealing temperature was 350 deg. C in vacuum (10{sup -3} Torr) for 1 h. X-ray diffraction analysis showed that the thin films formed were polycrystalline AgSbSe{sub 2} or AgSb(S,Se){sub 2} depending on selenium content in the precursor films. Morphology and elemental analysis of these films were done using scanning electron microscopy and energy dispersive X-ray spectroscopy. Optical band gap was evaluated from the UV-visible absorption spectra of these films. Electrical characterizations were done using Hall effect and photocurrent measurements. A photovoltaic structure: glass/ITO/CdS/AgSbSe{sub 2}/Al was formed, in which CdS was deposited by chemical bath deposition. J-V characteristics of this structure showed V{sub oc} = 435 mV and J{sub sc} = 0.08 mA/cm{sup 2} under illumination using a tungsten halogen lamp. Preparation of a photovoltaic structure using AgSbSe{sub 2} as an absorber material by a non-toxic selenization process is achieved.

  17. In situ scanning tunneling microscopy investigation of sulfur oxidative underpotential deposition on Ag(100) and Ag(110).

    Science.gov (United States)

    Lastraioli, E; Loglio, F; Cavallini, M; Simeone, F C; Innocenti, M; Carlà, F; Foresti, M L

    2010-11-16

    Underpotential (UPD) deposition of sulfur from Na(2)S solution in 0.1 M NaOH was studied on Ag(100) and Ag(110) using in situ scanning tunneling microscopy (STM). The cyclic voltammogram on Ag(100) presents two broad peaks, whereas three partial overlapping peaks and a sharper one are observed on Ag(110). STM measurements carried out during the whole UPD process show that progressively more compact structures are formed as the applied potential is scanned toward more positive potentials. More precisely, p(2×2), c(2×6), and c(2×2) were found on Ag(100) at E = -1.25, -1.0, and -0.9 V, respectively. Less definite conclusions can be drawn for the structures of S overlayers on Ag(110). However, the experimental findings are consistent with an incomplete p(2×1) at potentials preceding the sharp peak, and with a c(2×2) structure at E = -0.9 V vs Ag/AgCl, KCl(sat). The coverage values calculated on the basis of the hypothesized structures have been compared with the values obtained from chronocoulometric measurements at the most positive potentials investigated. Thus, the experimental coverage θ = 0.5 coincides with the coverage calculated for the c(2×2) structure found on Ag(110) at E = -0.9 V by STM, whereas the experimental coverage θ = 0.42 suggests that a mixture of structures c(2×6) and c(2×2) is formed on Ag(100).

  18. Synthesis and characterization of Ag-containing calcium phosphates with various Ca/P ratios

    Energy Technology Data Exchange (ETDEWEB)

    Gokcekaya, Ozkan, E-mail: gokcekaya@dc.tohoku.ac.jp [Department of Materials Processing, Tohoku University, 6-6-02 Aza Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Ueda, Kyosuke; Narushima, Takayuki [Department of Materials Processing, Tohoku University, 6-6-02 Aza Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Ergun, Celaletdin [Faculty of Mechanical Engineering, Istanbul Technical University, 65 Inonu Street, Gumussuyu, Istanbul 34437 (Turkey)

    2015-08-01

    Ag-containing calcium phosphate (CaP) powders were synthesized by a precipitation method using aqueous solutions of calcium nitrate, silver nitrate, and ammonium phosphate. The powders were sintered at temperatures ranging from 1173 to 1473 K. The charged atomic ratios of (Ca + Ag)/P and Ag/(Ca + Ag) in solution were varied from 1.33 to 1.67 and from 0 to 0.30, respectively. The Ag content in the as-precipitated CaP powders increased with the charged Ag/(Ca + Ag) atomic ratio in solution and was lower than the charged Ag/(Ca + Ag) value. The as-precipitated CaP powders consisted of hydroxyapatite (HA) as the main phase. Ag nanoparticles were observed on the as-precipitated HA particles under all conditions of Ag addition. After the sintering, HA, β-TCP (tricalcium phosphate), α-TCP, and β-CPP (calcium pyrophosphate) were mainly detected as CaPs on the basis of the Ca/P atomic ratio of the as-precipitated powders. The addition of Ag stabilized the β-TCP phase, and the distribution of Ag in β-TCP was homogeneous. A metallic Ag phase coexisted with HA. The solubility of Ag in HA was estimated to be 0.0019–0.0061 (Ag/(Ca + Ag)) atomic ratio, which was lower than that in β-TCP (higher than 0.0536) and higher than that of β-CPP (below the detection limit of analyses). - Highlights: • The HA powders with Ag nanoparticles were synthesized by a precipitation method. • Metallic Ag particles were detected with the HA phase after sintering. • The distribution of Ag in β-TCP was homogeneous after sintering. • The addition of Ag stabilized the β-ΤCP phase. • β-TCP exhibited higher solubility of Ag than HA and β-CPP.

  19. Inbuilt Potential of YEM Medium and Its Constituents to Generate Ag/Ag2O Nanoparticles

    OpenAIRE

    Yamal, G.; Sharmila, P.; Rao, K. S.; Pardha-Saradhi, P.

    2013-01-01

    We discovered that Yeast Extract Mannitol (YEM) medium possessed immense potential to generate silver nanoparticles from AgNO3 upon autoclaving, which was evident from (i) alteration in color of the medium; (ii) peak at ∼410 nm in UV-Vis spectrum due to surface plasmon resonance specific to silver nanoparticles; and (iii) TEM investigations. TEM coupled with EDX confirmed that distinct nanoparticles were composed of silver. Yeast extract and mannitol were key components of YEM medium responsi...

  20. Fabrication of plasmonic AgBr/Ag nanoparticles-sensitized TiO2 nanotube arrays and their enhanced photo-conversion and photoelectrocatalytic properties

    Science.gov (United States)

    Wang, Qingyao; Qiao, Jianlei; Jin, Rencheng; Xu, Xiaohui; Gao, Shanmin

    2015-03-01

    Plasmonic photosensitizer AgBr/Ag nanospheres supported on TiO2 nanotube arrays (TiO2 NTs) are prepared by successive ionic layer adsorption and reaction (SILAR) technique followed by photoreduction methods. The structural and surface morphological properties of AgBr/Ag nanoparticles sensitized TiO2 NTs and their photoelectrochemical performance are investigated and discussed. A detailed formation mechanism of the TiO2 NTs/AgBr/Ag is proposed. The TiO2 NTs/AgBr/Ag exhibit excellent photocurrent and photoelectrocatalytic activities under visible light irradiation. Efficient utilization of solar energy to create electron-hole pairs is attributed to the significant visible light response and surface plasmon resonance of Ag nanoparticles. This finding indicates that the high photosensitivity of the TiO2 NTs-based surface plasmon resonance materials could be applied toward the development of new plasmonic visible-light-sensitive photovoltaic fuel cells and photocatalysts.

  1. Pulsed laser deposition of nanostructured Ag films

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, Tony [School of Physics, Trinity College, Dublin 2 (Ireland); Doggett, Brendan [School of Physics, Trinity College, Dublin 2 (Ireland); Lunney, James G. [School of Physics, Trinity College, Dublin 2 (Ireland)]. E-mail: jlunney@tcd.ie

    2006-04-30

    Ultra-thin (0.5-5 nm) films of Ag have been prepared by pulsed laser deposition in vacuum using a 26 ns KrF excimer laser at 1 J cm{sup -2}. The deposition was controlled using a Langmuir ion probe and a quartz crystal thickness monitor. Transmission electron microscopy showed that the films are not continuous, but are structured on nanometer size scales. Optical absorption spectra showed the expected surface plasmon resonance feature, which shifted to longer wavelength and increased in strength as the equivalent film thickness was increased. It is shown that Maxwell Garnett effective medium theory can be used to calculate the main features of optical absorption spectra.

  2. Incoherent Ag islands growth on Ni(100)

    Science.gov (United States)

    Marie, J. B.; Braems, I.; Bellec, A.; Chacon, C.; Creuze, J.; Girard, Y.; Gueddani, S.; Lagoute, J.; Repain, V.; Rousset, S.

    2017-02-01

    Growth of two-dimensional superstructure and island morphologies of silver atoms evaporated on a nickel (100) surface are studied by scanning tunneling microscopy. Near-equilibrium islands form at moderate annealing temperature (lower than 500 K) and present two kinds of morphologies. While they share a common monolayer c(2×8) superstructure, two distinct populations of islands coexist: rounded islands grown on the surface and spindle-shaped islands grown inside the Ni surface. The latter present a clear saturation of their density with increasing coverage. These shapes are mostly dominated by boundary energies as confirmed by a simple two-dimensional Wulff model whose parameters are derived using molecular statics simulations. Further annealing to 700 K leads to long Ag strips decorating the Ni step edges.

  3. Biomedical Potential of Ultrafine Ag/AgCl Nanoparticles Coated on Graphene with Special Reference to Antimicrobial Performances and Burn Wound Healing.

    Science.gov (United States)

    Zhou, Yazhou; Chen, Ru; He, Tingting; Xu, Kai; Du, Dan; Zhao, Nan; Cheng, Xiaonong; Yang, Juan; Shi, Haifeng; Lin, Yuehe

    2016-06-22

    In recent years, researchers have proven the release of silver ions (Ag(+)) from silver nanoparticles (Ag NPs) significantly affects their toxicity to bacteria and other organisms. Due to the difficulty in maintaining a steady flux of a high concentration of Ag(+), it is still challenging to develop a highly efficient, stable, and biocompatible Ag NP-based antimicrobial material. To circumvent this issue, we developed a new Ag-based bactericide through the fabrication of sunlight-driven and ultrafine silver/silver chloride anchored on reduced graphene oxide (Ag/AgCl/rGO). This stable Ag/AgCl nanophotocatalyst with negligible release of Ag(+) generated a high amount of oxidative radicals, killing the bacteria, thus achieving both high bactericidal efficiency and stability. Moreover, functionalization of the nanomaterial with poly(diallyldimethylammonium chloride) (PDDA) gives it a highly adsorptive capacity, which allows it to capture the bacteria and possibly enhances the bactericidal activity. In vivo histopathological studies showed that the Ag/AgCl/rGO nanomaterial could obviously promote the regeneration of the epidermis, which indicated the good biomedical potential of Ag/AgCl/rGO nanomaterial in burn wound healing.

  4. Evidence for improvement of critical current by Ag in YBaCuO-Ag thick films

    Science.gov (United States)

    Dwir, B.; Kellett, B.; Mieville, L.; Pavuna, D.

    1991-04-01

    The evidence is reported for enhancement of critical current density J(c) in YBa2Cu3O(7-delta) thick films with the addition of Ag, which is correlated with improvements in structural properties. An improvement of 50 percent in J(c) (up to about 500 A/sq cm at T = 4.2 K) was obtained in films made from YBCO + 60 wt pct Ag powder, fabricated by the spin-on technique on (100) SrTiO3, which is correlated with improvements in structure. The resulting films are 10 microns thick, uniform, partially textured, and show good adherence. The critical temperature Tc is improved by the addition of Ag, and a reduction in the density of microcracks and in the amount of secondary phases in the sintered films was observed. Normal-state resistivity is reduced by almost three orders of magnitude, making these films potentially useful for electronic applications in interconnects and novel hybrid circuits.

  5. Evidence for improvement of critical current by Ag in YBaCuO-Ag thick films

    Energy Technology Data Exchange (ETDEWEB)

    Dwir, B.; Kellett, B.; Mieville, L.; Pavuna, D. (Institute of Micro- and Opto-electronics, Department of Physics, Swiss Federal Institute of Technology, CH-1015 Lausanne, Switzerland (CH))

    1991-04-15

    The evidence is reported for enhancement of critical current density {ital J}{sub {ital c}} in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thick films with the addition of Ag, which is correlated with improvements in structural properties. An improvement of 50% in {ital J}{sub {ital c}} (up to {similar to}500 A/cm{sup 2} at {ital T}=4.2 K) was obtained in films made from YBCO+60wt % Ag powder, fabricated by the spin-on technique on (100) SrTiO{sub 3}, which is correlated with improvements in structure. The resulting films are 10 {mu}m thick, uniform, partially textured, and show good adherence. The critical temperature {ital T}{sub {ital c}} is improved by the addition of Ag, and a reduction in the density of microcracks and in the amount of secondary phases in the sintered films was observed. Normal-state resistivity is reduced by almost three orders of magnitude, making these films potentially useful for electronic applications in interconnects and novel hybrid circuits.

  6. Electronic structure of LaAg{sub 5} alloy films on Ag(111)

    Energy Technology Data Exchange (ETDEWEB)

    Seibel, Christoph; Bentmann, Hendrik; Forster, Frank [Universitaet Wuerzburg, Experimentelle Physik VII, Am Hubland, D-97074 Wuerzburg (Germany); Moreschini, Luca [Ecole Polytechnique Federale de Lausanne (EPFL), Institut de Physique des Nanostructures, CH-1015 Lausanne (Switzerland); Bihlmayer, Gustav [Institut fuer Festkoerperforschung, Forschungszentrum Juelich, D-52425 Juelich (Germany); Reinert, Friedrich [Universitaet Wuerzburg, Experimentelle Physik VII, Am Hubland, D-97074 Wuerzburg (Germany); Forschungszentrum Karlsruhe, Gemeinschaftslabor fuer Nanoanalytik, D-76021 Karlsruhe (Germany)

    2010-07-01

    We have characterized the growth of La on Ag(111) by UPS, XPS and LEED. At La coverages of about 4 ML or higher and subsequent annealing we observe an ordered (2x2) surface structure that is rotated by 30 with respect to the substrate. In analogy to the well-studied system CePt{sub 5}, we identify our system as a LaAg{sub 5} alloy in a CaCu{sub 5}-type structure. Employing angle-resolved photoelectron spectroscopy (ARPES) we measured the band structure along high symmetry lines and the Fermi surface (FS) of the LaAg{sub 5} films. We find several sharp bands near the Fermi level and a high anisotropy in the FS. Our results are compared to ARPES results on CePt{sub 5} and LaPt{sub 5} as well as first-principles calculations. The system shall serve as a reference for iso-structural alloys composed of other lanthanoids, such as Ce or Gd, potentially showing Kondo physics or other magnetic effects.

  7. Structure and Property of AgLaY Alloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The structure of RE-Ag alloy was observed and analyzed using electron probe. The property changes of the alloy containing two rare earth elements AgLaY during cold forming and the high temperature softening-resistance during annealing were studied using Vickers hardness tester. The distribution and action of the rare earth elements in Ag-alloy were also analyzed. Experimental results show that AgLaY alloy has more remarkable work-hardening effect than AgLa and pure silver, and it also has better thermal-resistance. The effects of RE elements, La and Y, on the properties of Ag-alloy are attributable to their symbiotic distribution and complementary function. Because of the common properties of La and Y as RE elements, they have the completely similar distribution in Ag-alloy. At the same time, La and Y make full use of complementary role in the alloy since they belong to different periods in periodic table and have differences in atomic structure and properties.

  8. Emission mechanism of radiophotoluminescence in Ag-doped phosphate glass

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, Y., E-mail: miyamoto-y@c-technol.co.j [Oarai Research Center, Chiyoda Technol Corpration, 3681 Narita-cho, Oarai-machi Higashi-ibaraki-gun, Ibaraki-ken 311-1313 (Japan); Yamamoto, T., E-mail: yamamoto-ta@c-technol.co.j [Oarai Research Center, Chiyoda Technol Corpration, 3681 Narita-cho, Oarai-machi Higashi-ibaraki-gun, Ibaraki-ken 311-1313 (Japan); Kinoshita, K. [Advanced Materials, Science Research, Development Center, Kanazawa Institute of Technology, 3-1 Yatsukaho, Hakusann-shi, Ishikawa-ken 924-0838 (Japan); Koyama, S., E-mail: s-koyama@neptune.kanazawa-it.ac.j [Advanced Materials, Science Research, Development Center, Kanazawa Institute of Technology, 3-1 Yatsukaho, Hakusann-shi, Ishikawa-ken 924-0838 (Japan); Takei, Y., E-mail: takei@neptune.kanazawa-it.ac.j [Advanced Materials, Science Research, Development Center, Kanazawa Institute of Technology, 3-1 Yatsukaho, Hakusann-shi, Ishikawa-ken 924-0838 (Japan); Nanto, H., E-mail: hnanto@neptune.kanazawa-it.ac.j [Advanced Materials, Science Research, Development Center, Kanazawa Institute of Technology, 3-1 Yatsukaho, Hakusann-shi, Ishikawa-ken 924-0838 (Japan); Shimotsuma, Y., E-mail: yshimo@collon1.kuic.kyoto-u.ac.j [Department of Materials Chemistry, Graduate School of Engineering, Kyoto University, A3-119 Katsura, Kyoto-University, Nishikyo-ku, Kyoto-shi, Kyoto-hu 615-8510 (Japan); Sakakura, M., E-mail: masa@collon1.kuic.kyoto-u.ac.j [Department of Materials Chemistry, Graduate School of Engineering, Kyoto University, A3-119 Katsura, Kyoto-University, Nishikyo-ku, Kyoto-shi, Kyoto-hu 615-8510 (Japan); Miura, K., E-mail: kmiura@collon1.kuic.kyoto-u.ac.j [Department of Materials Chemistry, Graduate School of Engineering, Kyoto University, A3-119 Katsura, Kyoto-University, Nishikyo-ku, Kyoto-shi, Kyoto-hu 615-8510 (Japan)

    2010-03-15

    The objective of this study is to investigate the emission mechanism of radiophotoluminescence (RPL) in the Ag{sup +}-doped phosphate glass (glass dosimeter), which is now used as individual radiation dosimeter, because the emission mechanism of RPL in glass dosimeter was not fully understood. Optical properties such as optical absorption spectrum, RPL spectrum and change of RPL spectrum as a function of X-ray irradiation dose were measured for commercially available glass dosimeter. In this study, we discuss the emission mechanism of two RPL peaks at 460 nm and 560 nm, based on the fact that electrons and holes produced by X-ray irradiation are trapped at Ag{sup +} ions to produce Ag{sup 0} and Ag{sup 2+} ions, respectively, when the Ag{sup +}-doped phosphate glass is exposed to X-ray. We would like to propose the emission mechanism of RPL peaks at 460 nm and 560 nm, concerning with Ag{sup 2+} and Ag{sup 0} ions.

  9. Gamma Radiolytic Formation of Alloyed Ag-Pt Nanocolloids

    Directory of Open Access Journals (Sweden)

    M. K. Temgire

    2011-01-01

    Full Text Available Colloidal dispersions of Ag-Pt composite nanoparticles were prepared by gamma radiolysis technique in the presence of nonionic surfactant Brij'97. Simultaneous as well as sequential reduction methods were employed in order to study the structural formation of Ag-Pt bimetallic clusters. Similar shape and trend was observed in optical spectra for both methods. Radiolysis yielded nearly spherical Ag-Pt bimetallic clusters by use of AgNO3 instead of AgClO4. The disappearance of the silver resonance and the simultaneous growth of the 260 nm resonance are independent of cluster structure and degree of alloying. To understand formation of Ag-Pt aggregate, the optical studies were also done as a function of amount of dose absorbed, concentration of surfactant, that is, Brij'97. The shape of the absorption spectrum did not change with increase in gamma radiation dose. TEM analysis exhibited fine dispersions of Ag-Pt clusters surrounded by a mantle when capped with Brij'97. The particle size obtained was in the range of 5–9 nm. On the basis of optical, XRD, and TEM analysis, alloy formation is discussed.

  10. [Clinical evaluation of a novel HBsAg quantitative assay].

    Science.gov (United States)

    Takagi, Kazumi; Tanaka, Yasuhito; Naganuma, Hatsue; Hiramatsu, Kumiko; Iida, Takayasu; Takasaka, Yoshimitsu; Mizokami, Masashi

    2007-07-01

    The clinical implication of the hepatitis B surface antigen (HBsAg) concentrations in HBV-infected individuals remains unclear. The aim of this study was to evaluate a novel fully automated Chemiluminescence Enzyme Immunoassay (Sysmex HBsAg quantitative assay) by comparative measurements of the reference serum samples versus two independent commercial assays (Lumipulse f or Architect HBsAg QT). Furthermore, clinical usefulness was assessed for monitoring of the serum HBsAg levels during antiviral therapy. A dilution test using 5 reference-serum samples showed linear correlation curve in range from 0.03 to 2,360 IU/ml. The HBsAg was measured in total of 400 serum samples and 99.8% had consistent results between Sysmex and Lumipulse f. Additionally, a positive linear correlation was observed between Sysmex and Architect. To compare the Architect and Sysmex, both methods were applied to quantify the HBsAg in serum samples with different HBV genotypes/subgenotypes, as well as in serum contained HBV vaccine escape mutants (126S, 145R). Correlation between the methods was observed in results for escape mutants and common genotypes (A, B, C) in Japan. Observed during lamivudine therapy, an increase in HBsAg and HBV DNA concentrations preceded the aminotransferase (ALT) elevation associated with drug-resistant HBV variant emergence (breakthrough hepatitis). In conclusion, reliability of the Sysmex HBsAg quantitative assay was confirmed for all HBV genetic variants common in Japan. Monitoring of serum HBsAg concentrations in addition to HBV DNA quantification, is helpful in evaluation of the response to lamivudine treatment and diagnosis of the breakthrough hepatitis.

  11. Cyclic voltammetry and near edge X-ray absorption fine structure spectroscopy at the Ag L3-edge on electrochemical halogenation of Ag layers on Au(111)

    Science.gov (United States)

    Endo, Osamu; Nakamura, Masashi

    2011-05-01

    One to three layers of Ag grown on a Au(111) electrode were studied by cyclic voltammetry in chloride and bromide solutions and by ex-situ near-edge X-ray absorption fine structure spectroscopy at the Ag L3-edge (Ag L3-NEXAFS). The one and two layers obtained by underpotential deposition exhibited reduced intensity at the absorption edge in the Ag L3-NEXAFS spectra, which suggests the gain of d-electrons in these layers. The cyclic voltammograms and the Ag L3-NEXAFS spectra indicate that the second and third layers of Ag halogenated at positive potentials, whereas the first layer remained in metallic form.

  12. Structural and optical properties of Si-doped Ag clusters

    KAUST Repository

    Mokkath, Junais Habeeb

    2014-03-06

    The structural and optical properties of AgN and Ag N-1Si1 (neutral, cationic, and anionic) clusters (N = 5 to 12) are systematically investigated using the density functional based tight binding method and time-dependent density functional theory, providing insight into recent experiments. The gap between the highest occupied and lowest unoccupied molecular orbitals and therefore the optical spectrum vary significantly under Si doping, which enables flexible tuning of the chemical and optical properties of Ag clusters. © 2014 American Chemical Society.

  13. Novel fluorescent chemosensor for Ag+ based on coumarin fluorophore

    Institute of Scientific and Technical Information of China (English)

    Mao Xiang Wang; Xiang Ming Meng; Man Zhou Zhu; Qing Xiang Guo

    2008-01-01

    A novel chemosensor 1 (CS1) bearing one coumarin and two carbodithioate groups was synthesized and its fluorescent sensing behavior toward metal ions was investigated. Ag+ addition to a CH3COCH3/H20 (3:7, v:v) solution of CS1 gave a significantly quenched fluorescence. Other ions including Pb2+, Zn2+, Cu2+, Ca2+, Cd2+, Co2+, Mg2+, Mn2+, Hg2+, Ag+, Ni2+ induced no or much smaller spectral changes. This constitutes an ON-OFF Ag+-selective fluorescent chemosensor.

  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. Large-Scale Self-Assembled Ag Nanotubes

    Institute of Scientific and Technical Information of China (English)

    WEI Guodan; NAN Cewen; YU Dapeng

    2005-01-01

    A high yield of silver nanotubes with large aspect ratio were conveniently synthesized via an organic-assist solvothermal preparation technique using polyvinyl pyrrolidone (PVP) as a capping reagent and architecture soft-template. The molecular ratio between the repeating unit of PVP and AgNO3 plays a crucial role in determining the geometric shape of the product. Such novel-type Ag nanotubes were self-assembled by Ag nanoparticles, which had largely similar crystallographic orientation, forming a texture. The fact that nanoparticles without anisotropic crystal structures can form such superstructures by self-assembly may open a window for understanding a range of nanotube formation processes.

  16. Effect of Sequential Ions Implantation on Structure of Cu, Ag Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    XIAO Xiang-heng; LU Zhuo-yu; GUO Li-ping; REN Feng; CHEN Dong-liang; WU Zi-yu; JIA Quan-jie

    2007-01-01

    The preparation of metal nanoparticles composites by Cu, Ag ions sequential implantation is studied. The formation of Cu, Ag nanoparticles has been evidenced by grazing incidence X-ray diffraction, extended x-ray absorption fine structure and transmission electron microscopy. With the increase of Ag ion implantation dose, the size and density of Ag nanoparticles increase significantly.

  17. 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.

  18. Prevalence of hepatitis B surface antigen (HBsAg) in blood donors from Bombay.

    Science.gov (United States)

    Satoskar, A; Ray, V

    1992-01-01

    Analysis of serum samples from 3104 blood donors from Bombay screened for hepatitis B surface antigen (HBsAg) by ELISA. HBsAg was detected in 4.7% of the subjects. Relatives showed a significantly higher prevalence of HBsAg than volunteer donors. There was no significant association between HBsAg positivity and a particular blood group.

  19. Development of heat resistant Pb-free joints by TLPS process of Ag and Sn-Bi-Ag alloy powders

    Directory of Open Access Journals (Sweden)

    Ohnuma I.

    2012-01-01

    Full Text Available TLPS (Transient Liquid Phase Sintering process is a candidate method of heat-resistant bonding, which makes use of the reaction between low-melting temperature powder of Sn-Bi base alloys and reactive powder of Ag. During heat treatment above the melting temperature of a Sn-Bi base alloy, the molten Sn-Bi reacts rapidly with solid Ag particles, which results in the formation of heat-resistant intermetallic compound (IMC. In this study, the TLPS properties between Sn-17Bi-1Ag (at.% powder with its liquidus temperature of 200°C and pure Ag powder were investigated. During differential scanning calorimetry (DSC measurement, an exothermic reaction and an endothermic reaction occurred, which correspond to the formation of the e-Ag3Sn IMC phase and the melting of the Sn-17Bi-1Ag alloy, respectively. After the overall measurement, the obtained reactant consists of the Ag3Sn-IMC and Bi-rich phases, both of which start melting above 250°C, with a small amount of the residual Sn-Bi eutectic phase. These results suggest that the TLPS process can be applied for Pb-free heatresistant bonding.

  20. Identification of Ag-acceptors in $^{111}\\!$Ag $^{111}\\!$Cd doped ZnTe and CdTe

    CERN Document Server

    Hamann, J; Deicher, M; Filz, T; Lany, S; Ostheimer, V; Strasser, F; Wolf, H; Wichert, T

    2000-01-01

    Nominally undoped ZnTe and CdTe crystals were implanted with radioactive $^{111}\\!$Ag, which decays to $^{111}\\!$Cd, and investigated by photoluminescence spectroscopy (PL). In ZnTe, the PL lines caused by an acceptor level at 121 meV are observed: the principal bound exciton (PBE) line, the donor-acceptor pair (DAP) band, and the two-hole transition lines. In CdTe, the PBE line and the DAP band that correspond to an acceptor level at 108 meV appear. Since the intensities of all these PL lines decrease in good agreement with the half-life of $^{111}\\!$Ag of 178.8 h, both acceptor levels are concluded to be associated with defects containing a single Ag atom. Therefore, the earlier assignments to substitutional Ag on Zn- and Cd-lattice sites in the respective II-VI semiconductors are confirmed. The assignments in the literature of the S$_1$, S$_2$, and S$_3$ lines in ZnTe and the X$\\scriptstyle^\\textrm{Ag}_{1}\\,\\,,$ X$\\scriptstyle^\\textrm{Ag}_{2}$/ C$\\scriptstyle^\\textrm{Ag}_{1}\\,$ and C$\\scriptstyle^\\textrm{...

  1. Silver bioaccumulation dynamics in a freshwater invertebrate after aqueous and dietary exposures to nanosized and ionic Ag

    Science.gov (United States)

    le Croteau, Marie-Noe; Misra, Superb K.; Luoma, Samuel N.; Valsami-Jones, Eugenia

    2011-01-01

    We compared silver (Ag) bioavailability and toxicity to a freshwater gastropod after exposure to ionic silver (Ag+) and to Ag nanoparticles (Ag NPs) capped with citrate or with humic acid. Silver form, exposure route, and capping agent influence Ag bioaccumulation dynamics in Lymnaea stagnalis. Snails efficiently accumulated Ag from all forms after either aqueous or dietary exposure. For both exposure routes, uptake rates were faster for Ag+ than for Ag NPs. Snails efficiently assimilated Ag from Ag NPs mixed with diatoms (assimilation efficiency (AE) ranged from 49 to 58%) and from diatoms pre-exposed to Ag+ (AE of 73%). In the diet, Ag NPs damaged digestion. Snails ate less and inefficiently processed the ingested food, which adversely impacted their growth. Loss rates of Ag were faster after waterborne exposure to Ag NPs than after exposure to dissolved Ag+. Once Ag was taken up from diet, whether from Ag+ or Ag NPs, Ag was lost extremely slowly. Large Ag body concentrations are thus expected in L. stagnalis after dietborne exposures, especially to citrate-capped Ag NPs. Ingestion of Ag associated with particulate materials appears as the most important vector of uptake. Nanosilver exposure from food might trigger important environmental risks.

  2. Influence of the surface properties on bactericidal and fungicidal activity of magnetron sputtered Ti–Ag and Nb–Ag thin films

    Energy Technology Data Exchange (ETDEWEB)

    Wojcieszak, D., E-mail: damian.wojcieszak@pwr.edu.pl [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wrocław (Poland); Mazur, M.; Kaczmarek, D. [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wrocław (Poland); Mazur, P. [Institute of Experimental Physics, University of Wrocław, Max Born 9, 50-204 Wrocław (Poland); Szponar, B. [Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Rudolfa Weigla 12, 53–114 Wrocław (Poland); Domaradzki, J. [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wrocław (Poland); Kepinski, L. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław (Poland)

    2016-05-01

    In this study the comparative investigations of structural, surface and bactericidal properties of Ti–Ag and Nb–Ag thin films have been carried out. Ti–Ag and Nb–Ag coatings were deposited on silicon and fused silica substrates by magnetron co-sputtering method using innovative multi-target apparatus. The physicochemical properties of prepared thin films were examined with the aid of X-ray diffraction, grazing incidence X-ray diffraction, scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy methods. Moreover, the wettability of the surface was determined. It was found that both, Ti–Ag and Nb–Ag thin films were nanocrystalline. In the case of Ag–Ti film presence of AgTi{sub 3} and Ag phases was identified, while in the structure of Nb–Ag only silver occurred in a crystal form. In both cases the average size of crystallites was ca. 11 nm. Moreover, according to scanning electron microscopy and atomic force microscopy investigations the surface of Nb–Ag thin films was covered with Ag-agglomerates, while Ti–Ag surface was smooth and devoid of silver particles. Studies of biological activity of deposited coatings in contact with Bacillus subtilis, Pseudomonas aeruginosa, Enterococcus hirae, Klebisiella pneumoniae, Escherichia coli, Staphylococcus aureus and Candida albicans were performed. It was found that prepared coatings were bactericidal and fungicidal even in a short term-contact, i.e. after 2 h. - Highlights: • Surface and biological properties of Ti–Ag and Nb–Ag thin films were examined. • Ag content was related to sputtering yields and nucleation of Ti and Nb. • For Nb–Ag film the agglomeration of silver at the surface was observed. • Composition and surface topography had an impact on antimicrobial properties. • Fine-grained surface was important in Ag ions release process.

  3. The Ratio of 2-AG to Its Isomer 1-AG as an Intrinsic Fine Tuning Mechanism of CB1 Receptor Activation

    Science.gov (United States)

    Dócs, Klaudia; Mészár, Zoltán; Gonda, Sándor; Kiss-Szikszai, Attila; Holló, Krisztina; Antal, Miklós; Hegyi, Zoltán

    2017-01-01

    Endocannabinoids are pleiotropic lipid messengers that play pro-homeostatic role in cellular physiology by strongly influencing intracellular Ca2+ concentration through the activation of cannabinoid receptors. One of the best-known endocannabinoid ‘2-AG’ is chemically unstable in aqueous solutions, thus its molecular rearrangement, resulting in the formation of 1-AG, may influence 2-AG-mediated signaling depending on the relative concentration and potency of the two isomers. To predict whether this molecular rearrangement may be relevant in physiological processes and in experiments with 2-AG, here we studied if isomerization of 2-AG has an impact on 2-AG-induced, CB1-mediated Ca2+ signaling in vitro. We found that the isomerization-dependent drop in effective 2-AG concentration caused only a weak diminution of Ca2+ signaling in CB1 transfected COS7 cells. We also found that 1-AG induces Ca2+ transients through the activation of CB1, but its working concentration is threefold higher than that of 2-AG. Decreasing the concentration of 2-AG in parallel to the prevention of 1-AG formation by rapid preparation of 2-AG solutions, caused a significant diminution of Ca2+ signals. However, various mixtures of the two isomers in a fix total concentration – mimicking the process of isomerization over time – attenuated the drop in 2-AG potency, resulting in a minor decrease in CB1 mediated Ca2+ transients. Our results indicate that release of 2-AG into aqueous medium is accompanied by its isomerization, resulting in a drop of 2-AG concentration and simultaneous formation of the similarly bioactive isomer 1-AG. Thus, the relative concentration of the two isomers with different potency and efficacy may influence CB1 activation and the consequent biological responses. In addition, our results suggest that 1-AG may play role in stabilizing the strength of cannabinoid signal in case of prolonged 2-AG dependent cannabinoid mechanisms. PMID:28265242

  4. Ethylene glycol-based Ag plating for the wet chemical fabrication of one micrometer Cu/Ag core/shell particles

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Eun Byul; Lee, Jong-Hyun, E-mail: pljh@snut.ac.kr

    2015-09-15

    Highlights: • Cu@Ag particles less than one micrometer were fabricated through Ag polyol-plating. • Ag polyol-plating was tried without using additional reagents on Cu core particles. • Continuity, uniformity, and thickness of the Ag shell depended on plating conditions. • The sample showed an excellent oxidation initiation temperature of 280 °C. • Anti-oxidation properties of Cu@Ag powders strongly depend on the Ag shell thickness. - Abstract: With the aim of preparing an inexpensive metal filler that can be added to conductive adhesives used in fine-pitch electronic applications, a polyol solution was used to fabricate Ag-coated Cu (Cu@Ag) particles with a size on the order of one micron without the need for additional reagents. The continuity, uniformity, and thickness of the Ag shell were found to be strongly dependent on the plating conditions, particularly the reaction temperature. The Ag shell prepared at a peak temperature of 180 °C from a precursor with an initial Ag concentration of 15 wt.% was judged to be an optimum one. This same sample also showed an excellent oxidation initiation temperature of approximately 280 °C. It was inferred that the oxidation resistance of the Cu@Ag powder is largely determined by the continuity, uniformity and thickness of the Ag shell.

  5. Degradation of microcystin-LR by highly efficient AgBr/Ag3PO4/TiO2 heterojunction photocatalyst under simulated solar light irradiation

    Science.gov (United States)

    Wang, Xin; Utsumi, Motoo; Yang, Yingnan; Li, Dawei; Zhao, Yingxin; Zhang, Zhenya; Feng, Chuanping; Sugiura, Norio; Cheng, Jay Jiayang

    2015-01-01

    A novel photocatalyst AgBr/Ag3PO4/TiO2 was developed by a simple facile in situ deposition method and used for degradation of mirocystin-LR. TiO2 (P25) as a cost effective chemical was used to improve the stability of AgBr/Ag3PO4 under simulated solar light irradiation. The photocatalytic activity tests for this heterojunction were conducted under simulated solar light irradiation using methyl orange as targeted pollutant. The results indicated that the optimal Ag to Ti molar ratio for the photocatalytic activity of the resulting heterojunction AgBr/Ag3PO4/TiO2 was 1.5 (named as 1.5 BrPTi), which possessed higher photocatalytic capacity than AgBr/Ag3PO4. The 1.5 BrPTi heterojunction was also more stable than AgBr/Ag3PO4 in photocatalysis. This highly efficient and relatively stable photocatalyst was further tested for degradation of the hepatotoxin microcystin-LR (MC-LR). The results suggested that MC-LR was much more easily degraded by 1.5 BrPTi than by AgBr/Ag3PO4. The quenching effects of different scavengers proved that reactive h+ and •OH played important roles for MC-LR degradation.

  6. Investigation of Ag-TiO2 Interfacial Reaction of Highly Stable Ag Nanowire Transparent Conductive Film with Conformal TiO2 Coating by Atomic Layer Deposition.

    Science.gov (United States)

    Yeh, Ming-Hua; Chen, Po-Hsun; Yang, Yi-Ching; Chen, Guan-Hong; Chen, Hsueh-Shih

    2017-03-20

    The atomic layer deposition (ALD) technique is applied to coat Ag nanowires (NWs) with a highly uniform and conformal TiO2 layer to improve the stability and sustainability of Ag NW transparent conductive films (TCFs) at high temperatures. The TiO2 layer can be directly deposited on Ag NWs with a surface polyvinylpyrrolidone (PVP) coat that acts a bed for TiO2 seeding in the ALD process. The ALD TiO2 layer significantly enhances the thermal stability at least 100 fold when aged between 200-400 °C and also provides an extra function of violet-blue light filtration for Ag NW TCFs. Investigation into the interaction between TiO2 and Ag reveals that the conformal TiO2 shell could effectively prevent Ag from 1D-to-3D ripening. However, Ag could penetrate the conformal TiO2 shell and form nanocrystals on the TiO2 shell surface when it is aged at 400 °C. According to experimental data and thermodynamic evaluation, the Ag penetration leads to an interlayer composed of mixed Ag-Ag2O-amorphous carbon phases and TiO2-x at the Ag-TiO2 interface, which is thought to be caused by extremely high vapor pressure of Ag at the Ag-TiO2 interface at a higher temperature (e.g., 400 °C).

  7. Influence of the surface properties on bactericidal and fungicidal activity of magnetron sputtered Ti-Ag and Nb-Ag thin films.

    Science.gov (United States)

    Wojcieszak, D; Mazur, M; Kaczmarek, D; Mazur, P; Szponar, B; Domaradzki, J; Kepinski, L

    2016-05-01

    In this study the comparative investigations of structural, surface and bactericidal properties of Ti-Ag and Nb-Ag thin films have been carried out. Ti-Ag and Nb-Ag coatings were deposited on silicon and fused silica substrates by magnetron co-sputtering method using innovative multi-target apparatus. The physicochemical properties of prepared thin films were examined with the aid of X-ray diffraction, grazing incidence X-ray diffraction, scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy methods. Moreover, the wettability of the surface was determined. It was found that both, Ti-Ag and Nb-Ag thin films were nanocrystalline. In the case of Ag-Ti film presence of AgTi3 and Ag phases was identified, while in the structure of Nb-Ag only silver occurred in a crystal form. In both cases the average size of crystallites was ca. 11 nm. Moreover, according to scanning electron microscopy and atomic force microscopy investigations the surface of Nb-Ag thin films was covered with Ag-agglomerates, while Ti-Ag surface was smooth and devoid of silver particles. Studies of biological activity of deposited coatings in contact with Bacillus subtilis, Pseudomonas aeruginosa, Enterococcus hirae, Klebisiella pneumoniae, Escherichia coli, Staphylococcus aureus and Candida albicans were performed. It was found that prepared coatings were bactericidal and fungicidal even in a short term-contact, i.e. after 2 h.

  8. Growth Kinetic of Ag Clots Created by Laser Light of Various Wavelength on Microcrystals AgBr

    Directory of Open Access Journals (Sweden)

    Yu.М. Lopatkin

    2013-03-01

    Full Text Available In this paper the kinetics of the growth of Ag clusters in AgBr microcrystals of the photographic emulsion SP-1 with sensitivity 6 units GOST during illuminating with laser radiation λ = 490 nm, Р = 10 mW; λ = 633 nm, Р = 10 mW, Р = 2.5 mW, Р = 0.98 mW; λ = 850 nm, Р = 10 mW; λ = 325 nm, Р = 3 mW was investigated using the computer model and found that the influence of the laser light power on the growth of Ag clusters more efficiently than the photon energy.

  9. Speciation and Lability of Ag-, AgCl- and Ag2S-Nanoparticles in Soil Determined by X-ray Absorption Spectroscopy and Diffusive Gradients in Thin Films

    Science.gov (United States)

    Long-term speciation and lability of silver (Ag-), silver chloride (AgCl-) and silver sulfide nanoparticles (Ag2S-NPs) in soil were studied by X-ray absorption spectroscopy (XAS), and newly developed "nano" Diffusive Gradients in Thin Films (DGT) devices. These nano-D...

  10. OXIDATION AND CHARACTERIZATION OF ACTIVE CARBON AG-5

    Directory of Open Access Journals (Sweden)

    Tatiana Goreacioc

    2015-06-01

    Full Text Available The surface chemistry of the commercial active carbon AG-5 has been modified by oxidation with concentrated nitric acid. The structural changes caused by oxidative treatment were estimated on the basis of nitrogen adsorption-desorption isotherms and thermal analysis. Boehm titration method and infrared spectral analysis have been used in order to evaluate surface chemistry characteristics of active carbon samples. After oxidation process the amount of total acidic groups on oxidized active carbon surface (AG-5ox increases by about 6 times in comparison with unmodified sample (AG-5. The concentration of the acidic groups on the oxidized active carbon surface (AG-5ox was in the following order: strong acidic >>> weak acidic > phenolic.

  11. Zoning Districts, ag-res, Published in 2008, Duchesne County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Zoning Districts dataset, was produced all or in part from Other information as of 2008. It is described as 'ag-res'. Data by this publisher are often provided...

  12. Design and status of the AGS booster accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Forsyth, E.B.; Lee, Y.Y.

    1987-01-01

    Comments are given on some areas of the design considered for the AGS Booster Accelerator, including lattice design, energy and repetition rate, injection, radio frequency system, and the vacuum system. The current status is then briefly described. (LEW)

  13. Communication: UV photoionization of cytosine catalyzed by Ag+

    Science.gov (United States)

    Taccone, Martín I.; Féraud, Geraldine; Berdakin, Matías; Dedonder-Lardeux, Claude; Jouvet, Christophe; Pino, Gustavo A.

    2015-07-01

    The photo-induced damages of DNA in interaction with metal cations, which are found in various environments, still remain to be characterized. In this paper, we show how the complexation of a DNA base (cytosine (Cyt)) with a metal cation (Ag+) changes its electronic properties. By means of UV photofragment spectroscopy of cold ions, it was found that the photoexcitation of the CytAg+ complex at low energy (315-282) nm efficiently leads to ionized cytosine (Cyt+) as the single product. This occurs through a charge transfer state in which an electron from the p orbital of Cyt is promoted to Ag+, as confirmed by ab initio calculations at the TD-DFT/B3LYP and RI-ADC(2) theory level using the SV(P) basis set. The low ionization energy of Cyt in the presence of Ag+ could have important implications as point mutation of DNA upon sunlight exposition.

  14. Communication: UV photoionization of cytosine catalyzed by Ag(+).

    Science.gov (United States)

    Taccone, Martín I; Féraud, Geraldine; Berdakin, Matías; Dedonder-Lardeux, Claude; Jouvet, Christophe; Pino, Gustavo A

    2015-07-28

    The photo-induced damages of DNA in interaction with metal cations, which are found in various environments, still remain to be characterized. In this paper, we show how the complexation of a DNA base (cytosine (Cyt)) with a metal cation (Ag(+)) changes its electronic properties. By means of UV photofragment spectroscopy of cold ions, it was found that the photoexcitation of the CytAg(+) complex at low energy (315-282) nm efficiently leads to ionized cytosine (Cyt(+)) as the single product. This occurs through a charge transfer state in which an electron from the p orbital of Cyt is promoted to Ag(+), as confirmed by ab initio calculations at the TD-DFT/B3LYP and RI-ADC(2) theory level using the SV(P) basis set. The low ionization energy of Cyt in the presence of Ag(+) could have important implications as point mutation of DNA upon sunlight exposition.

  15. Metal enhanced fluorescence of Ag-nanoshell dimer

    Science.gov (United States)

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

    2014-04-01

    The plasmon modes of Ag-nanoshell dimer on metal enhanced fluorescence (MEF) are studied theoretically. The amplified excitation rate of a dimer (two identical Ag nanoshells) illuminated by a plane wave for exciting a molecule located at the gap center is calculated. Subsequently, the apparent quantum yield of the emission of the excited molecule affected by the dimer is investigated. The multiple multipole method is used for the both simulations. Finally, the enhancement factor of the dimer on the overall photoluminescence of the molecule in terms of the two parameters is evaluated. Our results show that Ag-nanoshell dimer is a dual-band photoluminescence enhancer for MEF at the bonding dipole and quadrupole modes. The former is broadband, and the latter narrowband. Both bands depend on the gap size. Moreover, the average enhancement factor of Ag-nanoshell dimer for MEF with a Stokes shift is discussed.

  16. Plasma-induced formation of flower-like Ag{sub 2}O nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zen-Hung; Ho, Chun-Hsien; Lee, Szetsen, E-mail: slee@cycu.edu.tw

    2015-09-15

    Graphical abstract: Flower-like Ag{sub 2}O nanostructures. - Highlights: • Flower-like Ag{sub 2}O nanostructures were synthesized from Ag colloids using plasma. • XPS was used to monitor plasma treatment effect on Ag colloids. • SERS of methyl orange was used to monitor the plasma oxidation–reduction processes. • Photocatalytic degradation of methylene blue was performed using Ag{sub 2}O. • Ag{sub 2}O is a more efficient visible light photocatalyst than Ag colloids. - Abstract: Plasma treatment effect on Ag colloids was investigated using X-ray photoelectron spectroscopy (XPS) and surface-enhanced Raman scattering (SERS) techniques. XPS showed that O{sub 2} plasma was critical in removing organic residues in Ag colloids synthesized using citric acid as a reducing agent. With O{sub 2} plasma treatment, Ag colloids were also oxidized to form flower-like Ag{sub 2}O nanostructures. The formation mechanism is proposed. The SERS spectral intensity of methyl orange (MO) adsorbed on Ag surface became deteriorated with O{sub 2} plasma treatment. Followed by H{sub 2} plasma treatment, the SERS intensity of MO on Ag regained, which indicated that Ag{sub 2}O has been reduced to Ag. Nonetheless, the reduction by H{sub 2} plasma could not bring Ag back to the original as-synthesized nanoparticle morphology. The flower-like nanostructure morphology still remained. The photocatalytic degradation reactions of methylene blue (MB) aqueous solutions were carried out using Ag colloids and Ag{sub 2}O nanostructures. The results show that Ag{sub 2}O is more efficient than Ag colloids and many other metal oxides for the photocatalytic degradation of MB in solution when utilizing visible light.

  17. Bioavailability of Ag(I) with Arthrobacter oxidas and Arthrobacter globiformis

    CERN Document Server

    Gelagutashvili, E; Ginturi, E; Bagdavadze, N; Kuchava, N; Tsakadze, K; Janjalia, M

    2012-01-01

    The biosorption of Ag(I)_ Arthrobacter species (Arthrobacter globiformis 151B and Arthrobacter oxidas 61B) was studied at simultaneous application of dialysis and atomic absorption analysis. The biosorption constants and nature of interaction for Ag(I) -Arthrobacter oxidas and Ag(I) -Arthrobacter globiformis were determined. The biosorption constants for Ag(I)- -Arthrobacter globiformis and for Ag(I) -Arthrobacter oxidas equal to 65.0 x10-4 and 35.0 x10-4 respectively.

  18. Microstructure, mechanical properties, bio-corrosion properties and antibacterial properties of Ti–Ag sintered alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Mian [Key Lab. for Anisotropy and Texture of Materials, Education Ministry of China, Northeastern University, Shenyang 110819 (China); Zhang, Erlin, E-mail: zhangel@atm.neu.edu.cn [Key Lab. for Anisotropy and Texture of Materials, Education Ministry of China, Northeastern University, Shenyang 110819 (China); Zhang, Lan [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)

    2016-05-01

    In this research, Ag element was selected as an antibacterial agent to develop an antibacterial Ti–Ag alloy by a powder metallurgy. The microstructure, phase constitution, mechanical properties, corrosion resistance and antibacterial properties of the Ti–Ag sintered alloys have been systematically studied by X-ray diffraction (XRD), scanning electron microscope (SEM), compressive test, electrochemical measurements and antibacterial test. The effects of the Ag powder size and the Ag content on the antibacterial property and mechanical property as well as the anticorrosion property have been investigated. The microstructure results have shown that Ti–Ag phase, residual pure Ag and Ti were the mainly phases in Ti–Ag(S75) sintered alloy while Ti{sub 2}Ag was synthesized in Ti–Ag(S10) sintered alloy. The mechanical test indicated that Ti–Ag sintered alloy showed a much higher hardness and the compressive yield strength than cp-Ti but the mechanical properties were slightly reduced with the increase of Ag content. Electrochemical results showed that Ag powder size had a significant effect on the corrosion resistance of Ti–Ag sintered alloy. Ag content increased the corrosion resistance in a dose dependent way under a homogeneous microstructure. Antibacterial tests have demonstrated that antibacterial Ti–Ag alloy was successfully prepared. It was also shown that the Ag powder particle size and the Ag content influenced the antibacterial activity seriously. The reduction in the Ag powder size was benefit to the improvement in the antibacterial property and the Ag content has to be at least 3 wt.% in order to obtain a strong and stable antibacterial activity against Staphylococcus aureus bacteria. The bacterial mechanism was thought to be related to the Ti{sub 2}Ag and its distribution. - Highlights: • Ti–Ag alloy with up to 99% antibacterial rate was developed by powder metallurgy. • The effects of the Ag powder size and the Ag content on the

  19. Hepatocellular carcinoma HBsAg positive in pregnancy.

    Science.gov (United States)

    Gonçalves, C S; Pereira, F E; de Vargas, P R; Ferreira, L S

    1984-01-01

    The authors present a case of hepatocellular carcinoma diagnosed in a pregnant woman (four months pregnancy). The clinical evolution was complicated because of a severe hypoglicemia and the patient died 12 weeks after admission. The fetus died before a tentative of surgical delivery. The patient was HBsAg positive and five out of eight sons (inclusively the fetus), were HBsAg positive. There was not indication that the pregnancy had enhanced the tumor evolution.

  20. Quadratite, AgCdAsS3

    DEFF Research Database (Denmark)

    Bindi, Luca; Spry, Paul G.; Bonazzi, Paola;

    2013-01-01

    A re-investigation of the crystal structure of quadratite, ideally AgCdAsS3, was undertaken using a single crystal from the type locality, Lengenbach, Binntal, Switzerland. The average of five electron microprobe analyses led to the empirical formula (Ag0.994Cd0.738Pb0.231Cu0.006Tl0.005Mn0.003Fe0...

  1. Antibacterial effect assessment of ZnS: Ag nanoparticles

    OpenAIRE

    Najme Parvin; Gholamreza Amiri; Vajihe Karbasizadeh

    2016-01-01

    Objective(s): A large ratio of surface to volume of nanoparticles in comparison with bulk ones, will increase the cell penetration and therefore their toxicity. Materials and Methods: Chemical precipitation method was used in order to synthesis of ZnS:Ag quantum dots. Their Physical properties and characteristics were assessed by X-ray diffraction, Ultra Violet-Visible Spectrophotometer, Transmission Electron Microscope and it was shown that the obtained ZnS:Ag quantum dots are cubic with hig...

  2. AGS vertical beta function measurements for Run 15

    Energy Technology Data Exchange (ETDEWEB)

    Harper, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ahrens, L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Schoefer, V. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-10-07

    One key parameter for running the AGS e ciently is by maintaining a low emit- tance. To measure emittance, one needs to measure the beta function throughout the cycle. This can be done by measuring the beta function at the ionization pro le mon- itors (IPM) in the AGS. This tech note delves into the motivation, the measurement, and some strides that were made throughout Run15.

  3. Wetting of Au and Ag particles on monocrystalline graphite substrates

    Institute of Scientific and Technical Information of China (English)

    Joonho Lee; Toshihiro Tanaka; Kazufumi Seo; Nobumitsu Hirai; Jung-Goo Lee; Hirotaro Mori

    2006-01-01

    The wetting behavior of Au and Ag particles on a monocrystalline graphite substrate was investigated using the microscopic sessile drop method under a purified Ar atmosphere at 1300 K. The measured contact angles of the liquid Au and Ag on monocrystalline graphite substrates of (0001) face were 129° and 124°, respectively. It is believed that the interaction at the interface is dominated by the physical bonding (van der Waal's interaction).

  4. Lattice Dynamic of Ag8SnSe6 Crystal

    Directory of Open Access Journals (Sweden)

    I.V. Semkiv

    2016-10-01

    Full Text Available The synthesis and structure properties of Ag8SnSe6 argyrodite are described. Argyrodite belongs to the orthorhombic space group Pmn21 with 15 atoms per primitive cell. Classification of the main phonon modes of crystal carried out. First-principles phonon-dispersion curves for argyrodite Ag8SnSe6 are calculated. Peak position in Raman spectra and IR-spectra was clarified.

  5. Phase-dependent corrosion of titanium-to-stainless steel joints brazed by Ag-Cu eutectic alloy filler and Ag interlayer

    Science.gov (United States)

    Lee, M. K.; Park, J. J.; Lee, J. G.; Rhee, C. K.

    2013-08-01

    The electrochemical corrosion properties of Ti-STS dissimilar joints brazed by a 72Ag-28Cu alloy filler and an Ag interlayer were studied in a 3.5% NaCl solution using potentiodynamic polarization and ac impedance spectroscopy. For a joint with a layered structure of Ti(base)/TiAg/Ag solid solution/Ag-Cu eutectic/STS(base), galvanic corrosion mostly occurred in the TiAg phase with a severe material loss, indicating that the TiAg layer acted as an anode in the galvanic couple in the layered joint. The Ag-rich solid solution layer was also corroded to a certain extent, but the corrosion in this layer was dominated by the selective pitting corrosion of the eutectic Cu-rich phase. With an increase in the brazing temperature, the Cu-rich phases disappeared owing to the enhanced isothermal solidification effect, leading to an improvement of the corrosion resistance.

  6. Super-SERS-active and highly effective antimicrobial Ag nanodendrites

    Science.gov (United States)

    Li, H. B.; Liu, P.; Liang, Y.; Xiao, J.; Yang, G. W.

    2012-07-01

    We have developed simple and green electrochemistry to synthesize Ag nanostructures with high purity, good crystallinity and smooth surface for applications as super-SERS (surface-enhanced Raman scattering), SERS-active substrates and with highly effective antimicrobial activities. This synthesis takes place in a clean and slow reaction environment without any chemical additives, which ensures an ultrahigh active surface of the as-synthesized Ag nanostructures owing to their purity, good crystallinity and smooth morphology. Using this method, we synthesized nearly perfect Ag nanodendrites (NDs), which exhibit super-SERS sensitivity when they are used to detect the SERS spectra of rhodamine 6G at concentrations as low as 5 × 10-16 M, and have an ultrahigh electromagnetic (EM) enhancement factor of the order of 1013, breaking through the theoretical limit of EM enhancement. Meanwhile, the as-synthesized Ag NDs possess highly effective antimicrobial activities for Escherichia coli, Candida albicans and Staphylococcus aureus, which are over 10 times that of silver nanoparticles. Additionally, the basic physics and chemistry involved in the fabrication of Ag nanostructures are pursued. These investigations show that silver nanostructures with highly active surfaces can make the most of Ag nanostructures functioning as super-SERS-active substrates and multiple antibiotics.

  7. Quantifying the origin of released Ag+ ions from nanosilver.

    Science.gov (United States)

    Sotiriou, Georgios A; Meyer, Andreas; Knijnenburg, Jesper T N; Panke, Sven; Pratsinis, Sotiris E

    2012-11-13

    Nanosilver is most attractive for its bactericidal properties in modern textiles, food packaging, and biomedical applications. Concerns, however, about released Ag(+) ions during dispersion of nanosilver in liquids have limited its broad use. Here, nanosilver supported on nanostructured silica is made with closely controlled Ag size both by dry (flame aerosol) and by wet chemistry (impregnation) processes without any surface functionalization that could interfere with its ion release. It is characterized by electron microscopy, atomic absorption spectroscopy, and X-ray diffraction, and its Ag(+) ion release in deionized water is monitored electrochemically. The dispersion method of nanosilver in solutions affects its dissolution rate but not the final Ag(+) ion concentration. By systematically comparing nanosilver size distributions to their equilibrium Ag(+) ion concentrations, it is revealed that the latter correspond precisely to dissolution of one to two surface silver oxide monolayers, depending on particle diameter. When, however, the nanosilver is selectively conditioned by either washing or H(2) reduction, the oxide layers are removed, drastically minimizing Ag(+) ion leaching and its antibacterial activity against E. coli . That way the bactericidal activity of nanosilver is confined to contact with its surface rather than to rampant ions. This leads to silver nanoparticles with antibacterial properties that are essential for medical tools and hospital applications.

  8. Polymorphism of Ag{sub 3}VO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Dinnebier, R.E.; Jansen, M. [Max-Planck-Inst. for Solid State Research, Stuttgart (Germany); Reichert, H. [Max-Planck-Inst. for Metal Research, Stuttgart (Germany); Kowalevsky, A.

    2007-07-01

    The polymorphism of Ag{sub 3}VO{sub 4} was investigated with temperature dependent synchrotron powder diffraction, and differential scanning calorimetry in the temperature range 295 K {<=} T {<=} 893 K. Three crystal structures of Ag{sub 3}VO{sub 4} were identified and determined from powder diffraction data: a-Ag{sub 3}VO{sub 4} (T = 295 K, C2/c, a = 10.2672(2) Aa, b = 4.9814(1) Aa, c = 10.2240(2) Aa, {beta} = 116.0(1) , V = 470.0(2) Aa{sup 3}), {beta}-Ag{sub 3}VO{sub 4} (T = 423 K, I anti 42m, a = 4.9968(1) Aa, c = 9.6911(3) Aa, V = 241.97(1) Aa{sup 3}), and {gamma}-Ag{sub 3}VO{sub 4} (T = 703 K, Fm anti 3m, a = 7.8386(1) Aa, V = 481.62(1) Aa{sup 3}). The crystal structures of all three phases of Ag{sub 3}VO{sub 4} can be described as cubic closed packed arrangements of [VO{sub 4}]{sup 3-} anions with the silver cations occupying all octahedral and tetrahedral voids. (orig.)

  9. Antibacterial activity of graphene supported FeAg bimetallic nanocomposites.

    Science.gov (United States)

    Ahmad, Ayyaz; Qureshi, Abdul Sattar; Li, Li; Bao, Jie; Jia, Xin; Xu, Yisheng; Guo, Xuhong

    2016-07-01

    We report the simple one pot synthesis of iron-silver (FeAg) bimetallic nanoparticles with different compositions on graphene support. The nanoparticles are well dispersed on the graphene sheet as revealed by the TEM, XRD, and Raman spectra. The antibacterial activity of graphene-FeAg nanocomposite (NC) towards Bacillus subtilis, Escherichia coli, and Staphylococcus aureus was investigated by colony counting method. Graphene-FeAg NC demonstrates excellent antibacterial activity as compared to FeAg bimetallic without graphene. To understand the antibacterial mechanism of the NC, oxidative stress caused by reactive oxygen species (ROS) and the glutathione (GSH) oxidation were investigated in the system. It has been observed that ROS production and GSH oxidation are concentration dependent while the increase in silver content up to 50% generally enhances the ROS production while ROS decreases on further increase in silver content. Graphene loaded FeAg NC demonstrates higher GSH oxidation capacity than bare FeAg bimetallic nanocomposite. The mechanism study suggests that the antibacterial activity is probably due to membrane and oxidative stress produced by the nanocomposites. The possible antibacterial pathway mainly includes the non-ROS oxidative stress (GSH oxidation) while ROS play minor role.

  10. Spectroscopic studies of jet-cooled CuAg

    Science.gov (United States)

    Bishea, Gregory A.; Marak, Ninette; Morse, Michael D.

    1991-10-01

    Resonant two-photon ionization spectroscopy has been applied to jet-cooled diatomic CuAg. Four band systems have been observed, three of which have been rotationally resolved and analyzed. The ground state is X 1Σ+ in symmetry, deriving from the 3d10Cu4d10Agσ2 molecular configuration. Its bond length has been determined as r0=2.3735±0.0006 Å (1σ error limits). Based on an analysis of the possible separated atom limits, three of the excited states observed (A 0+, A' 1, and B' 0+ ) are assigned as primarily 3d9Cu4d10Agσ2σ* in character. The observation of unusually large electronic isotope shifts in the A-X, A'-X, and B'-X band systems, similar in magnitude to those previously observed in the A-X and B-X systems of Cu2 and the s←d excitations in atomic copper, provides further confirmation that these excited states derive from the 3d9Cu4d10Agσ2σ* molecular configuration. Finally, the highest energy state observed in this work is argued to be primarily ion pair in character, and is expected to have significant contributions from both the Cu+Ag- and Cu-Ag+ ion pair states.

  11. β - Ag2Te: A topological insulator with strong anisotropy

    Science.gov (United States)

    Wang, Lan; Sulaev, Azat; Ren, Peng; Xia, Bin; Lin, Qinghua; Yu, Ting; Qiu, Caiyu; Zhang, Shuang-Yuan; Han, Ming-Yong; Li, Zhipeng; Zhu, Wei Guang; Wu, Qingyu; Feng, Yuan Ping; Shen, Lei; Shen, Shun-Qing

    2013-03-01

    We present evidence of topological surface states in β-Ag2Te through first-principles calculations, periodic quantum interference effect and ambipolar electric field effect in single crystalline nanoribbon. Our first-principles calculations show that β-Ag2Te is a topological insulator with a gapless Dirac cone with strong anisotropy. To experimentally probe the topological surface state, we synthesized high quality β-Ag2Te nanoribbons and performed electron transport measurements. The coexistence of pronounced Aharonov-Bohm oscillations and weak Altshuler-Aronov-Spivak oscillations clearly demonstrates coherent electron transport around the perimeter of β-Ag2Te nanoribbon and therefore the existence of topological surface states, which is further supported by the ambipolar electric field effect for devices fabricated by β-Ag2Te nanoribbons. The experimentally confirmed topological surface states and the theoretically predicted isotropic Dirac cone of β-Ag2Te suggest that the material may be a promising material for fundamental study and future spintronic devices. RCA-08/018 (Singapore), MOE2010-T2-2-059 (Singapore), HKU705150P (Hong Kong), NTU-SUG M4080513

  12. Integrated mRNA and micro RNA profiling reveals epigenetic mechanism of differential sensitivity of Jurkat T cells to AgNPs and Ag ions.

    Science.gov (United States)

    Eom, Hyun-Jeong; Chatterjee, Nivedita; Lee, Jeongsoo; Choi, Jinhee

    2014-08-17

    In our previous in vitro study of the toxicity on silver nanoparticles (AgNPs), we observed a dramatically higher sensitivity of Jurkat T cells to AgNPs than to Ag ions, and DNA damage and apoptosis were found to be involved in that toxicity. In this study, to understand underlying mechanism of different sensitivity of Jurket T cells to AgNPs and Ag ions, mRNA microarray and micro RNA microarray were concomitantly conducted on AgNPs and Ag ions exposed Jurkat T cells. Surprisingly only a small number of genes were differentially expressed by exposure to each of the silver (15 altered mRNA by AgNPs exposure, whereas 4 altered mRNA by Ag ions exposure, as determined 1.5-fold change as the cut-off value). miRNA microarray revealed that the expression of 63 miRNAs was altered by AgNPs exposure, whereas that of 32 miRNAs was altered by Ag ions exposure. An integrated analysis of mRNA and miRNA expression revealed that the expression of hsa-miR-219-5p, was negatively correlated with the expression of metallothionein 1F (MT1F) and tribbles homolog 3 (TRIB3), in cells exposed to AgNPs; whereas, the expression of hsa-miR-654-3p was negatively correlated with the expression of mRNA, endonuclease G-like 1 (EDGL1) in cells exposed to Ag ions. Network analysis were further conducted on mRNA-miRNA pairs, which revealed that miR-219-5p-MT1F and -TRIB3 pairs by AgNPs are being involved in various cellular processes, such as, oxidative stress, cell cycle and apoptosis, whereas, miR-654-3p and ENDOGL1 pair by Ag ions generated a much simpler network. The putative target genes of AgNPs-induced miR-504, miR-33 and miR-302 identified by Tarbase 6.0 are also found to be involved in DNA damage and apoptosis. These results collectively suggest that distinct epigenetic regulation may be an underlying mechanism of different sensitivity of Jurkat T cells to AgNPs and Ag ion. Further identification of putative target genes of DE miRNA by AgNPs and Ag ions may provide additional clues for the

  13. A novel P/Ag/Ag2O/Ag3PO4/TiO2 composite film for water purification and antibacterial application under solar light irradiation.

    Science.gov (United States)

    Zhu, Qi; Hu, Xiaohong; Stanislaus, Mishma S; Zhang, Nan; Xiao, Ruida; Liu, Na; Yang, Yingnan

    2017-01-15

    TiO2-based thin films have been intensively studied in recent years to develop efficient photocatalyst films to degrade refractory organics and inactivate bacteria for wastewater treatment. In the present work, P/Ag/Ag2O/Ag3PO4/TiO2 composite films on the inner-surface of glass tube were successfully prepared via sol-gel approach. P/Ag/Ag2O/Ag3PO4/TiO2 composite films with 3 coating layers, synthesized at 400°C for 2h, showed the optimal photocatalytic performance for rhodamine B (Rh B) degradation. The results indicated that degradation ratio of Rh B by P/Ag/Ag2O/Ag3PO4/TiO2 composite film reached 99.9% after 60min under simulated solar light, while just 67.9% of Rh B was degraded by pure TiO2 film. Moreover, repeatability experiments indicated that even after five recycling runs, the photodegradation ratio of Rh B over composite film maintained at 99.9%, demonstrating its high stability. Photocatalytic inactivation of E. coli with initial concentration of 10(7)CFU/mL also showed around 100% of sterilization ratio under simulated solar light irradiation in 5min by the composite film. The radical trapping experiments implied that the major active species of P/Ag/Ag2O/Ag3PO4/TiO2 composite films were photo-generated holes and O2(-) radicals. The proposed photocatalytic mechanism shows that the transfer of photo-induced electrons and holes may reduce the recombination efficiency of electron-hole pairs and potential photodecomposition of composite film, resulting in enhanced photocatalytic ability of P/Ag/Ag2O/Ag3PO4/TiO2 composite films.

  14. Synthesis, characterization and excellent photocatalytic activity of Ag/AgBr/MoO{sub 3} composite photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jimei; Shi, Yali; Ren, Mingsong; Hu, Gang [Anhui University, Key Laboratory of Functional Inorganic Materials Chemistry of Anhui Province, College of Chemistry and Chemical Engineering, Hefei, Anhui (China)

    2014-09-15

    A novel composite photocatalyst Ag/AgBr/MoO{sub 3} was successfully synthesized via a simple precipitation method at room temperature. The obtained products were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy and UV-vis diffuse reflectance spectroscopy in detail. The photocatalytic activity of the samples was evaluated by monitoring the degradation of rhodamine B (RhB) solution under visible-light irradiation. The results showed that the photocatalytic activity of Ag/AgBr/MoO{sub 3} composite significantly enhanced and the degradation ratio of RhB reached 97.7 % after 15 min only. The excellent photocatalytic activity might be closely related to the large surface area, porosity structure and efficient separation of photoinduced electron-hole pairs. The possible reaction mechanism was also discussed. (orig.)

  15. Comparison of Ag/Al2O3 and Ag-ZSM5 catalysts for the selective reduction of NO with propylene in the presence of oxygen

    NARCIS (Netherlands)

    Furusawa, Takeshi; Lefferts, Leon; Seshan, Kulathuiyer; Aika, Ken-ichi

    2003-01-01

    The selective reduction of NO (0.1%) with propylene (0.1%) in the presence of oxygen (5%) was studied using two Ag catalysts (Ag-ZSM5, Ag/Al2O3) in view of the reaction mechanism within the temperature range of 473¿773 K. Ag/Al2O3 showed high and stable activity more than 24 h, while the activity of

  16. 2005 AG20/20 Annual Review

    Science.gov (United States)

    Ross, Kenton W.; McKellip, Rodney D.

    2005-01-01

    Topics covered include: Implementation and Validation of Sensor-Based Site-Specific Crop Management; Enhanced Management of Agricultural Perennial Systems (EMAPS) Using GIS and Remote Sensing; Validation and Application of Geospatial Information for Early Identification of Stress in Wheat; Adapting and Validating Precision Technologies for Cotton Production in the Mid-Southern United States - 2004 Progress Report; Development of a System to Automatically Geo-Rectify Images; Economics of Precision Agriculture Technologies in Cotton Production-AG 2020 Prescription Farming Automation Algorithms; Field Testing a Sensor-Based Applicator for Nitrogen and Phosphorus Application; Early Detection of Citrus Diseases Using Machine Vision and DGPS; Remote Sensing of Citrus Tree Stress Levels and Factors; Spectral-based Nitrogen Sensing for Citrus; Characterization of Tree Canopies; In-field Sensing of Shallow Water Tables and Hydromorphic Soils with an Electromagnetic Induction Profiler; Maintaining the Competitiveness of Tree Fruit Production Through Precision Agriculture; Modeling and Visualizing Terrain and Remote Sensing Data for Research and Education in Precision Agriculture; Thematic Soil Mapping and Crop-Based Strategies for Site-Specific Management; and Crop-Based Strategies for Site-Specific Management.

  17. Synthesis and properties of calix[4]arene telluropodant ethers as Ag+ selective sensors and Ag+, Hg2+ extractants

    Directory of Open Access Journals (Sweden)

    Yang Lu

    2009-10-01

    Full Text Available Three novel phenyltelluroalkoxyl functionalized tweezer-like calix[4]arenes 6–8 and two monophenyltelluropropoxyl functionalized calix[4]arenes 10 (cone conformer and 12 (partial cone conformer were synthesized and characterized. They are good Ag+-selective ionophores in ion-selective electrodes evaluated by electromotive force measurements of polymer membrane electrodes. The tweezer-like ionophores 6–8 showed excellent extraction ability towards Ag+ and Hg2+.

  18. Plasticity and microstructure of epitaxial Ag/Ni multilayers; Mechanische Eigenschaften und Mikrostruktur epitaktischer Ag/Ni-Multilagenschichten

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Tobias K.

    2007-10-15

    To meet the still increasing technical demands of new materials, it is required to improve basic knowledge of thin films and multilayers. This thesis describes the microstructure and mechanical behaviour of thin epitaxial Ag/Ni-multilayers. Former investigations were only done on polycrystalline multilayers or epitaxial single layers. The manufacture of epitaxial Ag/Ni-multilayers on (111) orientated Si-substrates was performed by a magnetron sputtering technique under ultra high vacuum (UHV). The thickness of the alternating Ag- and Ni-layers varies between 100 and 400 nm, the thickness of the whole film varies between 200 and 800 nm. Hardness and flow stress of Ag/Ni-multilayers were measured with a nanoindentation technique, a substrate curvature method and by X-ray diffraction. The hardness of these multilayers varies between 1.5 and 2.0 GPa. The Ag single film hardness is 0.5 GPa and Ni film 1.8 GPa. The flow stress of the Ag/Ni-multilayers varies between 350 and 800 MPa. The Ag single layer shows a flow stress of 100 MPa and Ni of 450 MPa. Both hardness and flow stress increase with decreasing layer thickness. In situ TEM and HRTEM experiments showed a semicoherent Ag/Ni-interface. It was observed that these interfaces act as sources and sinks. Dislocation loops formed at the interface expand and shrink according to the stress state. They combine with loops from the opposite interface or with the interface itself and form threading dislocations. Dislocation loops penetrating an interface were not observed. Results were compared with various models which simulate flow stress in thin films and multilayers. The most important models are calculated by Nix-Freund, the Source-model after von Blanckenhagen and the Hall-Petch-model. (orig.)

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

    Science.gov (United States)

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

    2016-08-17

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

  20. Calculation of thermodynamic functions of saturated solid solution of AgIn2Te3I compound in the Ag-In-Te-I system

    Science.gov (United States)

    Moroz, Mykola; Prokhorenko, Sergiy; Prokhorenko, Myroslava; Reshetnyak, Oleksandr

    2016-12-01

    Triangulation of Ag-In-Te-I system in the vicinity of AgIn2Te3I compound was investigated by X-ray diffraction and differential thermal analysis methods. The spatial position of the phase region AgIn2Te3I-InTe-Ag2Te-AgI regarding the figurative point of silver was used in order to write the equation of virtual potential-forming reaction. Potential-forming reaction was performed in electrochemical cell (ECC) of the type (-) C | Ag | Ag3GeS3I(Br) glass | D | C (+) where C are inert (graphite) electrodes; Ag and D are the electrodes of the ECC; D represents the alloy of four-phase region; Ag3GeS3I glass is a membrane with purely ionic Ag+ conductivity). Linear dependence of the EMF of cell on temperature in the range of 440-480 K was used to calculate the standard thermodynamic functions of saturated solid solution of AgIn2Te3I compound in Ag-In-Te-I system.

  1. Ultrasonic-assisted preparation of plasmonic ZnO/Ag/Ag2WO4 nanocomposites with high visible-light photocatalytic performance for degradation of organic pollutants.

    Science.gov (United States)

    Pirhashemi, Mahsa; Habibi-Yangjeh, Aziz

    2017-04-01

    In this work, plasmonic ternary ZnO/Ag/Ag2WO4 nanocomposites as efficient visible-light-driven photocatalysts prepared by a facile ultrasonic-irradiation method. The as-prepared samples were characterized by XRD, SEM, TEM, EDX, XPS, UV-vis DRS, FT-IR, and PL techniques. The photocatalytic performance of the prepared ZnO/Ag/Ag2WO4 nanocomposites were evaluated by photodegradations of rhodamine B, methylene blue, methyl orange, and fuchsine under visible-light irradiation. The optimal nanocomposite with 15wt% of Ag/Ag2WO4 to ZnO showed the highest photocatalytic activity for RhB degradation, which is about 95 and 19 times higher than those of the Ag/Ag2WO4 and ZnO samples, respectively. The highly enhanced activity of the ZnO/Ag/Ag2WO4 (15%) nanocomposite was attributed to the surface plasmon resonance effect of metallic silver and the formation of heterojunctions between the counterparts, which effectively suppresses recombination of the photogenerated charge carriers. Lastly, the plasmon-enhanced photocatalytic mechanism associated with the ZnO/Ag/Ag2WO4 nanocomposites was discussed.

  2. Catalytic synthesis of matchstick-like Ag2Se-ZnSe hetero-nanorods using Ag2S nanocrystals as seeds

    Science.gov (United States)

    Fan, Weiling; Yu, Huan; Lu, Chunhua; Wang, Lin; Long, Lingliang; Wu, Yanjun; Wang, Junli

    2015-04-01

    In nanowire catalytic growth, the catalyst particles usually remain at the tip of as-grown nanowires, which can be utilized to prepare matchstick-like heterostructures at the nanoscale. Based on this feature and a solution-phase catalytic growth route, we herein report the synthesis of Ag2Se-ZnSe matchstick-like hetero-nanorods, consisting of Ag2Se head and ZnSe rod-like stem. Three different kinds of silver sources, including Ag(0), Ag2S, and Ag2Se, are selected as initial seeds for growing ZnSe crystalline nanowire/rods. By comparison with the case of Ag(0) or Ag2Se, the use of Ag2S nanoparticles, which alter the chemical composition of catalytic particles and convert to Ag2Se catalyst after adding Se precursor (SeO2), is highly effective for the formation of uniform Ag2Se-ZnSe hetero-nanorods. The reason for this result may be attributed to a synergistic effect between the size of catalyst particles and the chemical conversion of Ag2S to Ag2Se.

  3. Effect of thermal annealing on the microstructures and photocatalytic performance of silver orthophosphate: The synergistic mechanism of Ag vacancies and metallic Ag

    Science.gov (United States)

    Yan, Tingjiang; Guan, Wenfei; Xiao, Ying; Tian, Jun; Qiao, Zheng; Zhai, Huishan; Li, Wenjuan; You, Jinmao

    2017-01-01

    In this work, a simple thermal annealing route has been developed to improve the photocatalytic performance of silver orthophosphate (Ag3PO4) photocatalyst toward organic pollutants degradation under visible light irradiation. The experimental results indicated that thermal treatment of Ag3PO4 led to an obvious lattice shift towards right and significantly narrowed band gap energies due to the formation of Ag vacancies and metallic Ag during Ag3PO4 decomposition. These structural variations notably affected the photocatalytic performance of Ag3PO4 photocatalysts. The activity of the annealed samples was found to be significantly enhanced toward the degradation of MO dye. The highest activity was observed over the sample annealed at 400 °C, which exceeded that of pristine Ag3PO4 by a factor of about 21 times. By means of photoluminescence spectroscopy and photoelectrochemical measurements, we propose that the enormous enhancement in activity was mainly attributed to the efficient separation of photogenerated electrons and holes driven by the synergistic effect of Ag vacancies and metallic Ag. The strong interaction between annealed particles also inhibited the dissolution of Ag+ from Ag3PO4 into aqueous solution, contributing to an improved photocatalytic stability. The strategy presented here provides an ideal platform for the design of other highly efficient and stable Ag-based photocatalysts for broad applications in the field of photocatalysis.

  4. Response properties of AgCl and AgBr under an external static electric field: A density functional study

    Science.gov (United States)

    Praveen, C. S.; Kokalj, A.; Rérat, M.; Valant, M.

    2012-10-01

    Density functional theory has been applied to investigate the effect of electric field on the electronic properties of AgCl and AgBr crystals using a static electric field perturbation. A reduction in the band gap value and widening of the band widths are observed with increase in the macroscopic field value indicating a considerable red shift in the absorption spectrum of AgCl and AgBr in the presence of an external electric field. Further, dielectric properties and lattice vibrations at the gamma point are calculated with three different functionals using the CPKS and the Berry phase approach as implemented in CRYSTAL09 code. Finally, the breakdown strength of AgCl and AgBr crystal is evaluated using Callen's equation. In contrast to the case of alkali halides, it is found that the inclusion of the numerically calculated effective mass ratio into the Callen's equation considerably improves the agreement between the calculated dielectric strength and the available experimental datum.

  5. Ozone decomposition on Ag/SiO{sub 2} and Ag/clinoptilolite catalysts at ambient temperature

    Energy Technology Data Exchange (ETDEWEB)

    Nikolov, Penko, E-mail: penmail@mail.bg [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Genov, Krassimir; Konova, Petya [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Milenova, Katya; Batakliev, Todor; Georgiev, Vladimir [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Kumar, Narendra [Laboratory of Industrial Chemistry, Process Chemistry Centre, Abo Akademi University, Biskopsgatan 8, 20500 Abo/Turku (Finland); Sarker, Dipak K. [School of Pharmacy and Biomolecular Sciences, University of Brighton, Lewes Road, Brighton BN2 4GJ (United Kingdom); Pishev, Dimitar [University of Chemical Technology and Metallurgy, 1756 Sofia (Bulgaria); Rakovsky, Slavcho [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

    2010-12-15

    Silver modified zeolite (Bulgarian natural clinoptilolite) and Ag/silica catalysts were synthesized by ion exchange and incipient wet impregnation method respectively and characterized by different techniques. DC arc-AES was used for Ag detection. XRD spectra show that Ag is loaded over the surface of the SiO{sub 2} sample and that after the ion-exchange process the HEU type structure of clinoptilolite is retained. UV-VIS (specific reflection at 310 nm) and IR (band at 695 cm{sup -1}) spectroscopy analysis proved that silver is loaded as a T-atom into zeolite channels as Ag{sup +}, instead of Na{sup +}, Ca{sup 2+}, or K{sup +} ions, existing in the natural clinoptilolite form. The samples Ag/SiO{sub 2} and Ag-clinoptilolite were tested as catalysts for decomposition of gas phase ozone. Very high catalytic activity (up to 99%) was observed and at the same time the catalysts remained active over time at room temperature.

  6. Size effects of Ag nanoparticles on plasmon-induced enhancement of photocatalysis of Ag-α-Fe₂O₃ nanocomposites.

    Science.gov (United States)

    Zhang, Shaofeng; Ren, Feng; Wu, Wei; Zhou, Juan; Sun, Lingling; Xiao, Xiangheng; Jiang, Changzhong

    2014-08-01

    Composite photocatalysts that consist of semiconductor and noble metal nanostructures have been considered to be the promising and crucial materials for straightforward improving the efficiency in photocatalytic process and for the conversion of solar to chemical energy. In this work, we fabricated Ag-α-Fe2O3 hybrid composites through a self-catalytic growth method by using the aldehyde-modified spindle α-Fe2O3 nanoparticles (NPs) as supports. The size of supported Ag NPs can be directly controlled on the surface of α-Fe2O3. The morphology and structure of the resulting Ag-α-Fe2O3 hybrid composites were studied by various techniques, including SEM, TEM, and XRD. The distinct photocatalytic behaviors were examined through the photodegradation of RhB dye. It was found that with the Ag NPs, the photocatalytic activities were enhanced greatly and the size of the Ag NPs played a crucial influence on the photocatalytic behaviors of the Ag-α-Fe2O3 composites.

  7. Localised Ag(+) vibrations at the origin of ultralow thermal conductivity in layered thermoelectric AgCrSe2.

    Science.gov (United States)

    Damay, F; Petit, S; Rols, S; Braendlein, M; Daou, R; Elkaïm, E; Fauth, F; Gascoin, F; Martin, C; Maignan, A

    2016-03-22

    In materials science, the substructure approach consists in imagining complex materials in which a particular property is associated with a distinct structural feature, so as to combine different chosen physical characteristics, which otherwise have little chance to coexist. Applied to thermoelectric materials, it has been used to achieve simultaneously phonon-glass and electron-crystal properties. Mostly studied for its superionic conductivity, AgCrSe2 is a naturally layered compound, which achieves very low thermal conductivity, ~0.4 W.K(-1).m(-1) at RT (room temperature), and is considered a promising thermoelectric. The Cr atoms of the [CrSe2]∞ layer bear a spin S = 3/2, which orders below TN = 55 K. Here we report low temperature inelastic neutron scattering experiments on AgCrSe2, alongside the magnetic field evolution of its thermal and electrical transport. We observe a very low frequency mode at 3 meV, ascribed to large anharmonic displacements of the Ag(+) ions in the [Ag]∞ layer, and 2D magnetic fluctuations up to 3 TN in the chromium layer. The low thermal conductivity of AgCrSe2 is attributed to acoustic phonon scattering by a regular lattice of Ag(+) oscillating in quasi-2D potential wells. These findings highlight a new way to achieve localised phonon modes in a perfectly crystalline solid.

  8. The Effect of Cu:Ag Atomic Ratio on the Properties of Sputtered Cu–Ag Alloy Thin Films

    Directory of Open Access Journals (Sweden)

    Janghsing Hsieh

    2016-11-01

    Full Text Available Cu–Ag thin films with various atomic ratios were prepared using a co-sputtering technique, followed by rapid thermal annealing at various temperatures. The films’ structural, mechanical, and electrical properties were then characterized using X-ray diffractometry (XRD, atomic force microscopy (AFM, FESEM, nano-indentation, and TEM as functions of compositions and annealing conditions. In the as-deposited condition, the structure of these films transformed from a one-phase to a dual-phase state, and the resistivity shows a twin-peak pattern, which can be explained in part by Nordheim’s Rule and the miscibility gap of Cu–Ag alloy. After being annealed, the films’ resistivity followed the mixture rule in general, mainly due to the formation of a dual-phase structure containing Ag-rich and Cu-rich phases. The surface morphology and structure also varied as compositions and annealing conditions changed. The recrystallization of these films varied depending on Ag–Cu compositions. The annealed films composed of 40 at % to 60 at % Cu had higher hardness and lower roughness than those with other compositions. Particularly, the Cu50Ag50 film had the highest hardness after being annealed. From the dissolution testing, it was found that the Cu-ion concentration was about 40 times higher than that of Ag. The galvanic effect and over-saturated state could be the cause of the accelerated Cu dissolution and the reduced dissolution of the Ag.

  9. Системи AgInSe2 – AgGaSe2 та AgInSe2 – Ag9GaSe6

    OpenAIRE

    Олексеюк, І. Д.; Іващенко, І. А.; Данилюк, І. В.; Olekseyuk, I. D.; I. A. Ivashchenko; Danylyuk, I. V.

    2010-01-01

    Враховуючи дані, отримані за результатами РФА, МСА, ДТА та поміру мікротвердості, було побудовано діаграми стану систем AgInSe2 – AgGaSe2 та AgInSe2 – Ag9GaSe6. У системі AgInSe2 – AgGaSe2 існує евтектична точка LE ↔ α + β при 1030 К та 24 мол. % AgGaSe2, де α – тверді розчини на основі високотемпературної модифікації (ВТМ) AgInSe2, β – тверді розчини на основі сполуки AgGaSe2 та низькотемпературної модифікації (НТМ) AgInSe2. Нескінченний ряд β-твердих розчинів кристалізується в с...

  10. Application of a newly developed high-sensitivity HBsAg chemiluminescent enzyme immunoassay for hepatitis B patients with HBsAg seroclearance.

    Science.gov (United States)

    Shinkai, Noboru; Matsuura, Kentaro; Sugauchi, Fuminaka; Watanabe, Tsunamasa; Murakami, Shuko; Iio, Etsuko; Ogawa, Shintaro; Nojiri, Shunsuke; Joh, Takashi; Tanaka, Yasuhito

    2013-11-01

    We modified and automated a highly sensitive chemiluminescent enzyme immunoassay (CLEIA) for surface antigen (HBsAg) detection using a combination of monoclonal antibodies, each for a specific epitope of HBsAg, and by improving an earlier conjugation technique. Of 471 hepatitis B virus (HBV) carriers seen in our hospital between 2009 and 2012, 26 were HBsAg seronegative as determined by the Abbott Architect assay. The Lumipulse HBsAg-HQ assay was used to recheck those 26 patients who demonstrated seroclearance by the Abbott Architect assay. The performance of the Lumipulse HBsAg-HQ assay was compared with that of a quantitative HBsAg detection system (Abbott Architect) and the Roche Cobas TaqMan HBV DNA assay (CTM) (lower limit of detection, 2.1 log copies/ml) using blood serum samples from patients who were determined to be HBsAg seronegative by the Abbott Architect assay. Ten patients had spontaneous HBsAg loss. Of 8 patients treated with nucleotide analogues (NAs), two were HBsAg seronegative after stopping lamivudine therapy and 6 were HBsAg seronegative during entecavir therapy. Eight acute hepatitis B (AH) patients became HBsAg seronegative. Of the 26 patients, 16 were HBsAg positive by the Lumipulse HBsAg-HQ assay but negative by the Abbott Architect assay. The differences between the two assays in terms of detectable HBsAg persisted over the long term in the spontaneous loss group (median, 10 months), the NA-treated group (2.5 months), and the AH group (0.5 months). In 9 patients, the Lumipulse HBsAg-HQ assay detected HBsAg when HBV DNA was negative by the CTM assay. HBsAg was also detected by the Lumipulse HBsAg-HQ assay in 4 patients with an anti-HBs concentration of >10 mIU/ml, 3 of whom had no HBsAg escape mutations. The automatic, highly sensitive HBsAg CLEIA Lumipulse HBsAg-HQ is a convenient and precise assay for HBV monitoring.

  11. Interface between C60 and Ag on nanostructured plasmonic Ag gratings: A SERS study

    Science.gov (United States)

    Khosroabadi, Akram A.; Matz, Dallas L.; Gangopadhyay, Palash; Pemberton, Jeanne E.; Norwood, Robert A.

    2013-09-01

    Nanostructured electrodes and interfaces can enhance light absorption in organic solar cells due to efficient light harvesting. Ultrathin films of an active layer (C60) deposited on nanostructured grating electrodes show more absorption as a result of increased light trapping. Plasmonic nanostructured electrodes with various geometries and dimensions have been fabricated on printed polyacrylonitrile (PAN) and subsequently characterized. Surface enhanced Raman scattering (SERS) measurements show significant signal enhancement (over two orders of magnitude) on nanostructured samples when compared to planar Ag substrates due to local electromagnetic field enhancement. Furthermore, conversion of PAN to graphitic carbon is evidenced in SERS spectra. The surface area was determined using underpotential deposition (UPD) of thallium and agrees with the geometric surface area calculated from SEM images. The FDTD simulated electric field distribution inside the samples confirms the experimental results. A 60 fold increase in the electric field results in three to four orders of magnitude enhancement in the SERS signal depending on the dimensions of the pillars and gratings. Further study of the interaction between a top organic layer (C60) and the Ag electrode will help us to understand the nanoscale charge transfer rate critical to optimization and design of efficient organic solar cells.

  12. Low temperature properties of organicinorganic Ag/p-CuPc/n-GaAs/Ag photoelectric sensor

    Institute of Scientific and Technical Information of China (English)

    Kh.; S.; KARIMOV; I.; QAZI; T.; A.; KHAN; M.; I.; FEDOROV

    2008-01-01

    A thin organic film of p-type semiconducting copper phthalocynanine (CuPc) was deposited by vacuum evaporation on an n-type GaAs single-crystal semiconductor substrate. The fabricated Ag/p-CuPc/n-GaAs/Ag sensor was carried through an ageing process to stabilize the parameters. Voltage-current characteristics and photoelectrical response of the sensor were investigated at a wide temperature range of 82 to 350 K. Photoelectric characteristics were measured under non-modulated filament-lamp illumination. It was observed that such sensor parameters as rectification ratio,threshold voltage,junction,shunt and series resistances,open-circuit voltage and short circuit current are temperature-dependent. It was found that wide-range voltage-current characteristics of the sensor may be de-scribed similarly to that of a Schottky barrier diode. Using the experimental data on voltage-current characteristics and absorbance of the CuPc films,the energy-band diagram of the p-CuPc/n-GaAs heterojunction was developed. It was shown that data obtained from simulation of an equivalent circuit of photoelectric sensor agreed with experimental results.

  13. Half-life determination for {sup 108}Ag and {sup 110}Ag

    Energy Technology Data Exchange (ETDEWEB)

    Zahn, Guilherme S.; Genezini, Frederico A. [Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP, P.O. Box 11049, São Paulo, 05422-970 (Brazil)

    2014-11-11

    In this work, the half-life of the short-lived silver radionuclides {sup 108}Ag and {sup 110}Ag were measured by following the activity of samples after they were irradiated in the IEA-R1 reactor. The results were then fitted using a non-paralizable dead time correction to the regular exponential decay and the individual half-life values obtained were then analyzed using both the Normalized Residuals and the Rajeval techniques, in order to reach the most exact and precise final values. To check the validity of dead-time correction, a second correction method was also employed by means of counting a long-lived {sup 60}Co radioactive source together with the samples as a livetime chronometer. The final half-live values obtained using both dead-time correction methods were in good agreement, showing that the correction was properly assessed. The results obtained are partially compatible with the literature values, but with a lower uncertainty, and allow a discussion on the last ENSDF compilations' values.

  14. Brookhaven highlights, July 1976-September 1978

    Energy Technology Data Exchange (ETDEWEB)

    1979-11-01

    Some of the most significant research accomplishments during this 27-month period are presented. Although some data are given, this report is primarily descriptive in outlook; detailed information on completed work should be sought from the references cited herein or from the usual sources of physics research information. The report is organized as follows: High-energy Physics (general introduction, physics research, accelerators, ISABELLE); Nuclear and Solid State Physics, and Chemistry; Life Sciences (biology, medicine); Applied Energy Science (energy and the environment, reactor systems and safety, National Nuclear Data Center, nuclear materials safeguards); Support Activities (applied mathematics, instrumentation, reactors, safety and environmental protection); and General and Administrative. 117 figures, 16 tables, 315 references. (RWR)

  15. Morphology Control and Optical Absorption Properties of Ag Nanoparticles by Ion Implantation

    Institute of Scientific and Technical Information of China (English)

    G.X. Cai; F. Ren; X.H. Xiao; L.X. Fan; X.D. Zhou; C.Z. Jiang

    2009-01-01

    Ion implantation is a powerful method for fabricating nanoparticles in dielectric. For the actual application of nanoparticle composites, a careful control of nanoparticles has to be achieved. In this letter, the size, distribution and morphology of Ag nanoparticles are controlled by controlling the ion current density, ion implantation sequence and ion irradiation dose. Single layer Ag nanoparticles are formed by Ag~+ ion implantation at current density of 2.5 μA/cm~2. By Ag and Cu ions sequential implantation, the size of single layer Ag nanoparticles increases. While, by Cu and Ag ions sequential implantation, uniform Ag nanoparticles with wide distribution are formed. The morphology of Ag nanoparticles changes to hollow and sandwiched nanoparticles by Cu~+ ion irradiation to doses of 3×10~(16) and 5×10~(16) ions/cm~2. The optical absorption properties of Ag nanoparticles are also tailored by these ways.

  16. Transformation of AgCl nanoparticles in a sewer system — A field study

    Energy Technology Data Exchange (ETDEWEB)

    Kaegi, Ralf, E-mail: ralf.kaegi@eawag.ch [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf (Switzerland); Voegelin, Andreas; Sinnet, Brian [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf (Switzerland); Zuleeg, Steffen [KUSTER + HAGER Group, Oberstrasse 222, 9014 St. Gallen (Switzerland); Siegrist, Hansruedi [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf (Switzerland); Burkhardt, Michael [HSR University of Applied Sciences, Institute of Environmental and Process Engineering (UMTEC), Oberseestrasse 10, 8640 Rapperswil (Switzerland)

    2015-12-01

    Silver nanoparticles (Ag-NP) are increasingly used in consumer products and their release during the use phase may negatively affect aquatic ecosystems. Research efforts, so far, have mainly addressed the application and use of metallic Ag(0)-NP. However, as shown by recent studies on the release of Ag from textiles, other forms of Ag, especially silver chloride (AgCl), are released in much larger quantities than metallic Ag(0). In this field study, we report the release of AgCl-NP from a point source (industrial laundry that applied AgCl-NP during a piloting phase over a period of several months to protect textiles from bacterial regrowth) to the public sewer system and investigate the transformation of Ag during its transport in the sewer system and in the municipal wastewater treatment plant (WWTP). During the study period, the laundry discharged ~ 85 g of Ag per day, which dominated the Ag loads in the sewer system from the respective catchment (72–95%) and the Ag in the digested WWTP sludge (67%). Combined results from electron microscopy and X-ray absorption spectroscopy revealed that the Ag discharged from the laundry to the sewer consisted of about one third AgCl and two thirds Ag{sub 2}S, both forms primarily occurring as nanoparticles with diameters < 100 nm. During the 800 m transport in the sewer channel to the nearby WWTP, corresponding to a travel time of ~ 30 min, the remaining AgCl was transformed into nanoparticulate Ag{sub 2}S. Ag{sub 2}S-NP also dominated the Ag speciation in the digested sludge. In line with results from earlier studies, the very low Ag concentrations measured in the effluent of the WWTP (< 0.5 μg L{sup −1}) confirmed the very high removal efficiency of Ag from the wastewater stream (> 95%). - Highlights: • First field study on the transformation of AgCl nanoparticles released from a point source into the municipal sewer system. • Transformation of AgCl-NP into Ag{sub 2}S already occurred during 30-min transport in the

  17. Microstructure and Raman spectra of Ag-MgF2 cermet films

    Institute of Scientific and Technical Information of China (English)

    Shouhua Shi(史守华); Zhuoliang Cao(曹卓良); Zhaoqi Sun(孙兆奇)

    2003-01-01

    Ag-MgF2 cermet films with different Ag fractions were prepared by vacuum evaporation. The microstruc-ture of the films was examined by Raman scattering technique. The surface-enhanced Raman spectrumfor MgF2 molecules in the cermet film strongly suggests the existence of Ag nanoparticles dispersed inMgF2 matrix. The intensities of the Raman spectra of Ag-MgF2 cermet films increase with Ag fraction.The enhancement of Raman scattering disappears when Ag content reaches wt.20%. The analyses withthe transmission electron microscopy showed that Ag-MgF2 cermet films are mainly composed of amor-phous MgF2 matrix with embedded faced-center-cubic Ag nanoparticles. It suggests that the percolationthreshold should be around wt.20% of Ag content.

  18. Reversible emission evolution from Ag activated zeolite Na-A upon dehydration/hydration

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Hui, E-mail: linh8112@163.com, E-mail: fujii@eedept.kobe-u.ac.jp; Imakita, Kenji; Fujii, Minoru, E-mail: linh8112@163.com, E-mail: fujii@eedept.kobe-u.ac.jp [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, Rokkodai, Nada, Kobe 657-8501 (Japan)

    2014-11-24

    Reversible emission evolution of thermally treated Ag activated zeolite Na-A upon dehydration/hydration in vacuum/water vapor was observed. The phenomenon was observed even for the sample with low Ag{sup +}-Na{sup +} exchanging (8.3%), indicating that the emission from Ag activated zeolites may not come from Ag clusters while from the surrounding coordinated Ag{sup +} ions or Ag{sup 0} atoms. It was disclosed that the characteristic yellow-green emission at ∼560 ± 15 nm is strongly associated with the coordinating water molecules to the Ag{sup +} ions or Ag{sup 0} atoms, which is clear evidence for that the efficient emission from Ag activated zeolites may not originate from the quantum confinement effect.

  19. Corrosion behavior of Ti-Ag alloys used in dentistry in lactic acid solution

    Science.gov (United States)

    Takahashi, Masatoshi; Kikuchi, Masafumi; Takada, Yukyo

    2011-02-01

    The purpose of this study was to evaluate the corrosion resistance of experimental Ti-Ag alloys used as dental materials. An elution test and a rest-potential measurement of alloys with 5-30 mass.% Ag were performed in a 1 % lactic acid solution. The amount of Ti ions released from the α phase of the Ti-Ag alloys decreased as the Ag concentration increased. TiAg present in the alloys dissolved preferentially, but Ti2Ag did not. The rest potentials of the Ti-Ag alloys were significantly higher than that of pure titanium. The elution test and the rest-potential measurement revealed that the Ti-Ag alloys, which formed a single α-titanium structure or contained a titanium and Ti2Ag, had excellent corrosion resistance that was comparable or superior to that of pure titanium.

  20. The role of exopolymeric substances in the bioaccumulation and toxicity of Ag nanoparticles to algae

    Science.gov (United States)

    Zhou, Kaijun; Hu, Yi; Zhang, Luqing; Yang, Kun; Lin, Daohui

    2016-09-01

    Exopolymeric substances (EPS) have an important role in bioaccumulation and toxicity of nanoparticles (NPs) to algae, which warrants specific studies. The interaction of EPS with citrate and polyvinyl pyrrolidone (PVP) coated AgNPs (C-AgNPs and P-AgNPs, respectively) and its roles in bioaccumulation and toxicity of the AgNPs to Chlorella pyrenoidosa were investigated. The amino and aromatic carboxylic groups in the EPS were involved in the EPS-AgNP interactions. Compared with Ag+, C-AgNPs had comparable total bioaccumulation but greater absorption by intact algae with EPS; P-AgNPs had the smallest total bioaccumulation and were mainly adsorbed on algal surfaces. With EPS removed, the total bioaccumulations and surface adsorptions for the three Ag species decreased but the cell internalizations increased; the 96 h half growth inhibition concentrations decreased, indicating EPS alleviated the algal toxicity of Ag. The cell-internalized but not the adsorbed AgNPs could contribute to the nanotoxicity. The EPS could bind both AgNPs and Ag+, and thus inhibited the cell internalization and the nanotoxicity. However, the EPS-bound Ag on the cell surfaces would migrate along with the algae and be biologically amplified in the aquatic food chains, presenting ecological risks. These results are helpful for understanding the fate and ecological effects of NPs.

  1. Distinct metal-exchange pathways of doped Ag25 nanoclusters

    KAUST Repository

    Bootharaju, Megalamane Siddaramappa

    2016-09-09

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

  2. Immunization with HBsAg-Fc fusion protein induces a predominant production of Th1 cytokines and reduces HBsAg level in transgenic mice

    Institute of Scientific and Technical Information of China (English)

    MENG Zhe-feng; WANG Hua-jing; YAO Xin; WANG Xuan-yi; WEN Yu-mei; DAI Jian-xin; XIE You-hua; XU Jian-qing

    2012-01-01

    Background The Fc receptor associated pathway might improve the immune responses against hepatitis B virus (HBV) as previously described by us.In addition,the Flt3 ligand (FL) has been reported to potentiate antigen presenting cells in vivo and may act as a potential adjuvant to boost antigen-specific immune responses.In this study,the immune efficacies of a set of fusion proteins of HBsAg and Fc and/or FL were evaluated in HBsAg transgenic mice.Methods The fusion proteins composed of HBsAg and the Fc domain of murine IgG1 (HBsAg-Fc) and/or the Flt3 ligand,and yeast-derived recombinant HBsAg were used as immunogen to immunize HBsAg transgenic mice,respectively.Serum and liver HBsAg levels,serum anti-HBsAg and cytokine profile,and the activities of alanine aminotransferase (ALT)/AST were investigated after immunization.Results After six injections,the most pronounced decrease in serum and liver HBsAg levels was observed in the HBsAg-Fc immunized group.In addition,serum Th1 cytokines and ALT/AST activities were highest in this group,indicating an effective induction of a favorable cellular immune response.Interestingly,the fusion protein containing HBsAg-Fc and the Flt3 ligand stimulated an alternative Th1-type immune response featured with high level productions of tumor necrosis factor α (TNF- α) and monocyte chemoabstractant protein 1 (MCP-1),causing a more severe cytotoxicity in hepatocytes while showed less effective in reducing serum HBsAg level.Conclusion HBsAg-Fc is effective in eliciting both the humoral and cellular immune responses against HBsAg in HBsAg transgenic mice,which makes it a potential immunogen for the immunotherapy of chronic hepatitis B.

  3. Adsorption and visible light-driven photocatalytic degradation of Rhodamine B in aqueous solutions by Ag@AgBr/SBA-15

    Science.gov (United States)

    Hu, Longxing; Yuan, Hang; Zou, Lianpei; Chen, Feiyan; Hu, Xing

    2015-11-01

    A novel composite, Ag@AgBr/SBA-15, was successfully synthesized by dispersion of AgBr on mesoporous silica SBA-15, characterized by several techniques, such as XRD, N2 adsorption-desorption, SEM & EDS, UV-vis spectrum and XPS, and utilized for visible light photocatalytic degradation of dye Rhodamine B (RhB) in aqueous solutions. The results showed that for the various AgBr loadings in the composites, RhB photocatalytic degradation efficiency arrived at the maximum of 77% at 50% loading, or with 50Ag@AgBr/SBA-15. Under the combined mode, the RhB removal reached 88% at 0.3 g/L of 50Ag@AgBr/SBA-15 dosage, 20 mg L-1 of initial RhB concentration, 4.28 of unadjusted initial pH and 20 °C. The RhB photocatalytic degradation followed well with the second-order kinetics, and the increase of the 50Ag@AgBr/SBA-15 dosage, the decrease of the initial RhB concentration and the optimal initial solution pH would be favorable to RhB photocatalytic degradation. The quenching tests demonstrated that the RhB photocatalytic degradation was mainly attributed to the generation of active species such as O2-,bigdot OH and h+. Moreover, the adsorption characteristics of 50Ag@AgBr/SBA-15 were investigated, with its pHpzc of 6.21 acquired and the conclusion that the RhB adsorption isotherm well followed Langmuir model drawn. Additionally, photocatalyst 50Ag@AgBr/SBA-15 can be effectively regenerated with the H2O2 solutions under visible light irradiation, and reused for up to five runs for the degradation of RhB in the presence of visible light, with RhB removal more than 75% and Ag+ leaching undetected for each run.

  4. AgBr/Ag2CO3异质结光催化剂的制备及其可见光响应活性%Preparation of AgBr/Ag2 CO3 Hybrids Photocatalyst and Its Visible-light-resonsive Photocatalytic Activity

    Institute of Scientific and Technical Information of China (English)

    戴杨叶; 张栌予; 尹玲玲; 陈健; 徐秀泉

    2016-01-01

    以硝酸银、碳酸钠为原料,通过共沉淀法获得Ag2 CO3纳米粒,并以该纳米粒为前体化合物,采用原位离子交换法合成系列AgBr/Ag2 CO3异质结可见光催化剂。采用XRD、 SEM测定了抑制结的组成和形貌。同时考察了该催化剂在可见光下(λ>420 nm)的光催化降解盐酸莫西沙星性能。结果表明AgBr与Ag2 CO3摩尔比为0.6时AgBr/Ag2 CO3有最高的光催化活性, AgBr/Ag2 CO3异质结光催化剂可有效提高Ag2 CO3光催化剂降解盐酸莫西沙星的活性和稳定性。%A series of AgBr/Ag2 CO3 hybrids with visible-light responsive using Ag 2 CO3 via in situ anion-exchange method were obtained.The composites were characterized by means of XRD and SEM .The hybridized composites displayed highest photocatalytic activity for the photodegradation of moxifloxacin hydrochloride pollutant under visible -light irradiation when the composites with the proportion 0.6 of AgBr to Ag2 CO3.AgBr/Ag2 CO3 hybrids can enhance the phtocatalytic activity and stability of Ag 2 CO3 for phtodegradation MX.

  5. Performance of the new AGS RFQ preinjector

    Energy Technology Data Exchange (ETDEWEB)

    Alessi, J.G.; Brennan, J.M.; Brodowski, J.; Brown, H.N.; Kponou, A.; LoDestro, V.; Montemurro, P.; Prelec, K.; Witkover, R.; Gough, R.; Staples, J.

    1989-01-01

    In the fall of 1988, the 750 keV Cockcroft-Walton (C-W) preinjector for the AGS 200 MeV H/sup /minus// linac was replaced by an RFQ, in what has proved to be a very successful upgrade. The motivations for the upgrade included improved reliability, simpler maintenance, and the added convenience of having the ion source located at nearly ground potential. At the same time, the controls and instrumentation in the preinjector area were modernized. The linac has been operating full time with this RFQ preinjector since January 1, 1989, and the reliability has been excellent. The source, RFQ, and linac operate at a 5 Hz repetition rate, and the beam pulse width is approximately 450 ..mu..s. At this time, the H/sup /minus// current at 200 MeV is typically 23-25 mA, the same as previous operation with the C-W, although the capability is there to reach higher currents in the future. The layout of the new preinjector is shown in Figure 1. An important consideration in the layout of this line was the decision to leave the final 2.4 m section before the linac intact, so the optics of a second C-W injector line and polarized H/sup /minus// injection from another RFQ remained the same. The resulting line has a distance of almost 6 m from the RFQ to the linac, and there are three ''rebuncher'' cavities to maintain the bunching of the beam from the RFQ. The following sections will describe some details of the preinjector line, and then discuss the installation and performance.

  6. Fabrication of a novel visible-light-driven photocatalyst Ag-AgI-TiO{sub 2} nanoparticles supported on carbon nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Dandan; Bai, Jie, E-mail: baijie@imut.edu.cn; Liang, Haiou; Wang, Junzhong; Li, Chunping

    2015-09-15

    Graphical abstract: - Highlights: • Visible-light-induced Ag-AgI-TiO{sub 2}/CNFs nanocomposites had been successfully prepared. • Ag-AgI-TiO{sub 2}/CNFs could be easily separated and recycled from an aqueous solution. • The application of CNFs acting as supporters made the photocatalysts have high adsorption capacity. • Ag-AgI-TiO{sub 2}/CNFs could efficiently degrade different organic dyes. - Abstract: Novel visible-light-driven photocatalysts Ag-AgI-TiO{sub 2} nanoparticles embedded onto carbon nanofibers were successfully prepared. Electrospinning technology followed by high-temperature calcination was adopted for the fabrication of carbon nanofibers (CNFs) acting as a supporter. Ag-TiO{sub 2}/CNFs nanocomposites were prepared by combining in situ reduction with physical adsorption process. Ag-AgI-TiO{sub 2}/CNFs were synthesized by oxidizing some silver nanoparticles (Ag NPs) contained in Ag-TiO{sub 2}/CNFs to silver iodine (AgI) via chemical oxidation method using iodine (I{sub 2}) as oxidation agents. The as-prepared nanocomposites were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectra (DRS), and Fourier transform infrared spectroscopy (FTIR). The as-fabricated Ag-AgI-TiO{sub 2}/CNFs showed high efficient adsorption and photocatalytic activity for decomposition of methyl orange (MO), acid red 18 (AR18), methylene blue (MB), and fluorescence sodium under visible light irradiation, which were attributed to the synergistic effects between the high adsorption capacity, good conductivity of carbon nanofibers, and the extraordinary plasma effect of Ag-AgI nanoparticles. In addition, the as-prepared composites could be easily separated from the solution phase due to the large length–diameter ratio of CNFs. The mechanism for the enhanced photocatalytic activity concerned with Ag-AgI-TiO{sub 2}/CNFs was proposed.

  7. Primary immunization-like response without hepatitis following transfusion of HBeAg-positive blood

    DEFF Research Database (Denmark)

    Gluud, C; Aldershvile, J; Kryger, P;

    1983-01-01

    An accidental transfusion of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) positive whole blood was given to a 19-yr-old male, bleeding after tonsillectomy. Serum obtained from the patient before the transfusion revealed no hepatitis B antigens or antibodies. After...... the transfusion the patient became HBsAg-positive, cleared this antigen and developed antibodies to both HBsAg and HBeAg. The transfusion blood was positive for total antibody and IgM antibody to hepatitis B core antigen (HBcAg). The patient's blood became positive for these antibodies after the transfusion...

  8. Thermal properties of radiolytically synthesized PVA/Ag nanocomposites

    Directory of Open Access Journals (Sweden)

    Krklješ Aleksandra N.

    2007-01-01

    Full Text Available The radiolytic method was used to synthesize two types of nanocomposites with silver, PVA/Ag by film casting and PVA hydrogel/Ag nanocomposites. This method is particularly suitable for generating metal nanoparticles in solution. The radiolytic species (solvated electrons and secondary radicals exhibit strong reducing properties such that metal ions are reduced at each encounter. Metal atoms then tend to grow into larger clusters. It was found that solid or swollen polymers are able to stabilize small crystallites against spontaneous growth via aggregation. Using differential scanning calorimetry (DSC, the melting behavior and kinetics of the PVA/Ag nanocomposites were investigated and compared to those of pure PVA. The melting as well as crystallization behavior of polymers is crucial because it governs the thermal properties, impact resistance and stress strain properties. Understanding the melting behavior is significant not only to tailor the properties of nanocomposites but to investigate the interactions between the constituents. The DSC curves of pure PVA and prepared nanocomposites show only one melting peak between 175 and 230°C, indicating that the melting behavior of these two systems are analogous. In both cases, with increasing heating rate, the melting peak shifts to a higher temperature, but with increasing Ag content the peak melting temperature is lower. When specimens are heated at high heating rate, the motion of PVA molecular chains cannot follow the heating temperature on time due to the influence of heat hysteresis, which leads to a higher peak melting temperature. When Ag nanoparticles are added they increase the heat transfer among the PVA molecular chains decreasing the melting temperature. The Ag content is a major factor affecting the degree of crystallinity. It was observed that at low nanofiller content, up to the 0.5 wt%, the degree of crystallinity of the nanocomposites increased, while at a higher content the

  9. Synthesis of photoactive AgCl/SBA-15 by conversion of silver nanoparticles into stable AgCl nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zienkiewicz-Strzalka, M., E-mail: gosiazienkiewicz@wp.pl [Department of Crystallography, Faculty of Chemistry, Maria Curie-Sklodowska University, sq. Maria Curie-Sklodowska 3, 20-031 Lublin (Poland); Pikus, S. [Department of Crystallography, Faculty of Chemistry, Maria Curie-Sklodowska University, sq. Maria Curie-Sklodowska 3, 20-031 Lublin (Poland)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer A new material AgCl/SBA-15 was synthesized and characterized. Black-Right-Pointing-Pointer New simple and effective approach of preparation was proposed. Black-Right-Pointing-Pointer AgCl/SBA-15 material was tested as an active agent during photodegradation of phenol and its photoactivity was confirmed. Black-Right-Pointing-Pointer The photoactive properties depend on AgCl nanoparticles present in the composite. - Abstract: In this work the results of synthesis the ordered mesoporous silica (SBA-15) in the presence of stable silver nanoparticles were presented. It has been proven that the proposed method leads to the synthesis of SBA-15 nanocomposite containing silver chloride nanoparticles, formed by the transformation of silver nanoparticles in the acidic conditions. Proposed one-pot procedure is simple and the one requirement is to prepare a stable solution of silver nanoparticles. In this work, silver nanoparticles were obtained during chemical reduction of [Ag(NH{sub 3}){sub 2}]{sup +} ions by formaldehyde. Silver nanoparticles solution can be used as a silver chloride source due to the application of the same polymer as a stabilizer of nanocrystals and structure directing agent of SBA-15. The final AgCl/SBA-15 materials show excellent structural ordering characteristic for this type of materials confirmed by diffraction measurements in range of small angles 2{theta}, transmission electron microscopy (TEM) and nitrogen adsorption/desorption measurements. AgCl nanoparticles were identified by diffraction measurements as chlorargyrite phase. The presence of silver nanoparticles in initial solution and their absence after synthesis were confirmed by UV-vis measurements. The photoactivity of obtained AgCl/SBA-15 composite was tested in reaction of organic impurities photodegradation.

  10. Influence of Ag contents on structure and tribological properties of TiSiN-Ag nanocomposite coatings on Ti-6Al-4V

    Science.gov (United States)

    Dang, Chaoqun; Li, Jinlong; Wang, Yue; Yang, Yitao; Wang, Yongxin; Chen, Jianmin

    2017-02-01

    TiSiN-Ag nanocomposite coatings with different Ag contents were deposited on Ti-6Al-4V using reactive co-sputtering in multi-arc ion plating system. Influence of Ag contents on structure and tribological properties of TiSiN-Ag nanocomposite coatings was investigated. The TiSiN-Ag coatings were found to have unique nanocomposite structures composed of nanocrystallite and amorphous nc-TiN/nc-Ag/a-Si3N4. When the silver content was 1.4 at.%, the coating exhibited high hardness (36 GPa), but poor wear resistance. When the silver content was increased from 5.3 to 8.7 at.%, the coatings possessed homogeneous distribution and small variation in hardness. Although these coatings revealed obvious decrease in hardness, significantly reduced in the friction coefficient and possessed excellent tribological properties, besides, the coating with the Ag content of 5.3 at.% showed best wear resistance in artificial seawater and the coating (7.9 at.% Ag) revealed the best wear resistance in ambient air. However, with a further increased incorporation of Ag into the TiSiN-Ag coating (17.0 at.%) resulted in the formation of a large volume fraction of metallic silver, which caused a decrease both in hardness and wear resistance. The coating containing highest Ag concentration (21.0 at.%) exhibited low friction coefficient both in ambient air and artificial seawater, although possessing low hardness.

  11. Asymmetrical Precipitation of Ag3Sn Intermetallic Compounds Induced by Thermomigration of Ag in Pb-Free Microbumps During Solid-State Aging

    Science.gov (United States)

    Su, Yu-Ping; Wu, Chun-Sen; Ouyang, Fan-Yi

    2016-01-01

    Three-dimensional integrated circuit technology has become a major trend in electronics packaging in the microelectronics industry. To effectively remove heat from stacked integrated circuitry, a temperature gradient must be established across the chips. Furthermore, because of the trend toward higher device current density, Joule heating is more serious and temperature gradients across soldered joints are expected to increase. In this study we used heat-sink and heat-source devices to establish a temperature gradient across SnAg microbumps to investigate the thermomigration behavior of Ag in SnAg solder. Compared with isothermal conditions, small Ag3Sn particles near the hot end were dissolved and redistributed toward the cold end under a temperature gradient. The results indicated that temperature gradient-induced movement of Ag atoms occurred from the hot side toward the cold side, and asymmetrical precipitation of Ag3Sn resulted. The mechanism of growth of the intermetallic compound (IMC) Ag3Sn, caused by thermomigration of Ag, is discussed. The rate of growth Ag3Sn IMC at the cold side was found to increase linearly with solid-aging time under a temperature gradient. To understand the force driving Ag diffusion under the temperature gradient, the molar heat of transport ( Q*) of Ag in Sn was calculated as +13.34 kJ/mole.

  12. Effect of Cu Addition on the Microstructure of Ag-Ce Alloys%Cu对Ag-Ce合金组织与结构之影响

    Institute of Scientific and Technical Information of China (English)

    俞建树; 贺晓燕; 周世平; 卢绍平; 安盈志; 王佳丽; 王健

    2013-01-01

    The effects of Cu addition on the microstructure of Ag-Ce alloy were studied by SEM and EDS. The results showed that the main body of Ag-Cu-Ce alloys is silver-copper solid solution with smaller crystal grains, in which many symbiotically separated β-Cu and Ag4Ce particles were distributed diffusively. Cu addition segregation. Tensile fracture of Ag-Ce and Ag-Cu-Ce alloys was shown cone and left distinct tough pit, which is typical tough break.%利用扫描电子显微镜和能谱仪分析Cu对Ag-Ce合金组织与结构的影响。结果表明:Ag-Cu-Ce合金基体为银铜固溶体,晶粒较小,基体上弥散分布着恀多共生析出的β-Cu和Ag4Ce颗粒,Cu的加入改善了Ag4Ce的偏析现象。Ag-Ce和Ag-Cu-Ce合金的拉伸断口呈锥形,有明显的韧窝组织,为典型的韧性断裂。

  13. Fabrication, characterization and photocatalytic properties of Ag/AgI/BiOI heteronanostructures supported on rectorite via a cation-exchange method

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yunfang [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Fang, Jianzhang, E-mail: fangjzh@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou 510006 (China); Lu, Shaoyou [Shenzhen Center for Disease Control and Prevention, Shenzhen 518055 (China); Wu, Yan; Chen, Dazhi; Huang, Liyan [Institute of Engineering Technology of Guangdong Province, Key Laboratory of Water Environmental Pollution Control of Guangdong Province, Guangzhou 510440 (China); Xu, Weicheng; Zhu, Ximiao [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Fang, Zhanqiang [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou 510006 (China)

    2015-04-15

    Highlights: • Ag/AgI/BiOI-rectorite was prepared by twice cation-exchange process. • Ag/AgI/BiOI-rectorite photocatalyst possessed SPR and adsorption capacity. • Ag/AgI/BiOI-rectorite exhibited highly photocatalytic activity. • Trapped holes and ·O{sub 2}{sup −} were formed active species in the photocatalytic system. - Abstract: In this work, a new plasmonic photocatalyst Ag/AgI/BiOI-rectorite was prepared via a cation exchange process. The photocatalyst had been characterized by X-ray powder diffraction (XRD), Raman spectra, nitrogen sorption (BET), field-emission scanning electron microscope (FE-SEM), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectroscopy (DRS). The photocatalytic activity, which was evaluated by degradation of rhodamine B (RhB) and bisphenol A (BPA) under visible light irradiation, was enhanced significantly by loading Ag/AgI/BiOI nanoparticles onto rectorite. The photogenerated holes and superoxide radical (·O{sub 2}{sup −}) were both formed as active species for the photocatalytic reactions under visible light irradiation. The existence of metallic Ag particles, which possess the surface plasmon resonance effect, acted as an indispensable role in the photocatalytic reaction.

  14. TRIBOLOGICAL PROPERTIES OF CrAgN THIN FILMS

    Directory of Open Access Journals (Sweden)

    Peter Jurči

    2013-04-01

    Full Text Available CrN and CrAgN thin films were magnetron sputtered onto the substrate made from Vanadis 6 cold work tool steel. The films were examined on tribological properties using a high temperature Pin-on-disc tribometer. Obtained results show that there is almost no effect of Ag addition on the friction coefficient when tested at a room temperature against alumina. The testing against the same counterpart at higher temperature gave positive effect of the silver addition on the friction coefficient. The testing against 100Cr6 ball bearing steel gave higher friction coefficient than that against alumina while the testing against CuSn6-bronze led to much lower μ. When tested at a room temperature, the wear performance of the films was positively affected only in the case of the CrAg3N film developed at 500 °C. On the other hand, addition of 3 wt% Ag into the CrN increased the wear performance at elevated temperatures while the addition of 15 wt% Ag has made the film too soft and sensitive to wear.

  15. Tribological properties of CrAgN thin films

    Directory of Open Access Journals (Sweden)

    Peter Jurči

    2013-02-01

    Full Text Available CrN and CrAgN thin films were magnetron sputtered onto the substrate made from Vanadis 6 cold work tool steel. The films were examined on tribological properties using a high temperature Pin-on-disc tribometer. Obtained results show that there is almost no effect of Ag addition on the friction coefficient when tested at a room temperature against alumina. The testing against the same counterpart at higher temperature gave positive effect of the silver addition on the m. The testing against 100Cr6 ball bearing steel gave higher friction coefficient than that against alumina while the testing against CuSn6-bronze led to much lower m. When tested at a room temperature, the wear performance of the films was positively affected only in the case of the CrAg3N film developed at 500 oC. On the other hand, addition of 3 wt% Ag into the CrN increased the wear performance at elevated temperatures while the addition of 15 wt% Ag has made the film too soft and sensitive to wear.

  16. Pirquitasite, Ag2ZnSnS4

    Directory of Open Access Journals (Sweden)

    Benjamin N. Schumer

    2013-02-01

    Full Text Available Pirquitasite, ideally Ag2ZnSnS4 (disilver zinc tin tetrasulfide, exhibits tetragonal symmetry and is a member of the stannite group that has the general formula A2BCX4, with A = Ag, Cu; B = Zn, Cd, Fe, Cu, Hg; C = Sn, Ge, Sb, As; and X = S, Se. In this study, single-crystal X-ray diffraction data are used to determine the structure of pirquitasite from a twinned crystal from the type locality, the Pirquitas deposit, Jujuy Province, Argentina, with anisotropic displacement parameters for all atoms, and a measured composition of (Ag1.87Cu0.13(Zn0.61Fe0.36Cd0.03SnS4. One Ag atom is located on Wyckoff site Wyckoff 2a (symmetry -4.., the other Ag atom is statistically disordered with minor amounts of Cu and is located on 2c (-4.., the (Zn, Fe, Cd site on 2d (-4.., Sn on 2b (-4.., and S on general site 8g. This is the first determination of the crystal structure of pirquitasite, and our data indicate that the space group of pirquitasite is I-4, rather than I-42m as previously suggested. The structure was refined under consideration of twinning by inversion [twin ratio of the components 0.91 (6:0.09 (6].

  17. The AGS Ggamma Meter and Calibrating the Gauss Clock

    Energy Technology Data Exchange (ETDEWEB)

    Ahrens, Leif [Brookhaven National Laboratory (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-03-31

    During AGS Polarized Proton acceleration periods, one output from the AGS Ggamma Meter, namely the energy (or Ggamma) calculated from the magnetic field in the AGS main magnets and the beam radius- both measured in particular instant, is used to figure out the times in the AGS magnet acceleration cycle when the beam passes through a particular set of depolarizing resonances. The resonance set occur whenever a particle’s Ggamma (energy*(G/m) becomes nearly equal to n*Qx (i.e. any integer multiplied by the horizontal betatron tune). This deliverable is why the machinery is referred to as the ''Ggamma Meter'' rather than the AGS energy meter. The Ggamma Meter takes as inputs a set of measurements of frequency (F(t)), radius (r(t)), and gauss clock counts (GCC(t)). The other energy (GgammaBr) assumes the field when the gauss clock starts counting is known. The change in field to time t is given by the measured accumulated gauss clock counts multiplied by the gauss clock calibration (gauss/GCC). In order to deal with experimental data, this calibration factor gets an added ad hoc complication, namely a correction dependent on the rate of change the counting rate. The Ggamma meter takes GCC(t) and together with the past history for this cycle calculates B(t).

  18. AgMIP Training in Multiple Crop Models and Tools

    Science.gov (United States)

    Boote, Kenneth J.; Porter, Cheryl H.; Hargreaves, John; Hoogenboom, Gerrit; Thornburn, Peter; Mutter, Carolyn

    2015-01-01

    The Agricultural Model Intercomparison and Improvement Project (AgMIP) has the goal of using multiple crop models to evaluate climate impacts on agricultural production and food security in developed and developing countries. There are several major limitations that must be overcome to achieve this goal, including the need to train AgMIP regional research team (RRT) crop modelers to use models other than the ones they are currently familiar with, plus the need to harmonize and interconvert the disparate input file formats used for the various models. Two activities were followed to address these shortcomings among AgMIP RRTs to enable them to use multiple models to evaluate climate impacts on crop production and food security. We designed and conducted courses in which participants trained on two different sets of crop models, with emphasis on the model of least experience. In a second activity, the AgMIP IT group created templates for inputting data on soils, management, weather, and crops into AgMIP harmonized databases, and developed translation tools for converting the harmonized data into files that are ready for multiple crop model simulations. The strategies for creating and conducting the multi-model course and developing entry and translation tools are reviewed in this chapter.

  19. Ag/AgBr/TiO2/AC复合光催化剂的制备及其性能研究%Preparation and Characterization of Ag/AgBr/TiO2/AC Photocatalyst

    Institute of Scientific and Technical Information of China (English)

    叶芳云; 杨露; 刘鹏

    2011-01-01

    针对TiO光催化剂目前在实际应用中所面临的可见光利用率低及悬浮体系中光催化剂易失活、难回收的问题,我们将TiO的改性与固定结合,首先利用溶胶-凝胶方法将TiO光催化剂负载在多孔性载体活性炭上,然后再通过沉积-沉淀法将AgBr沉积于TiO表面,得到最终产物Ag/AgBr/TiO复合物光催化剂,同时利用溶胶-凝胶法在相同条件下合成纯TiO.通过XRD、SEM和光催化降解次甲基蓝溶液来对比两者的性能.结果显示Ag/AgBr/TiO/AC具有较好的可见光催化活性,三小时内次甲基蓝溶液的降解率达81.63%,而纯TiO三小时内只降解了15.74%.

  20. Chestnut extract induces apoptosis in AGS human gastric cancer cells.

    Science.gov (United States)

    Lee, Hyun Sook; Kim, Eun Ji; Kim, Sun Hyo

    2011-06-01

    In Korea, chestnut production is increasing each year, but consumption is far below production. We investigated the effect of chestnut extracts on antioxidant activity and anticancer effects. Ethanol extracts of raw chestnut (RCE) or chestnut powder (CPE) had dose-dependent superoxide scavenging activity. Viable numbers of MDA-MD-231 human breast cancer cells, DU145 human prostate cancer cells, and AGS human gastric cancer cells decreased by 18, 31, and 69%, respectively, following treatment with 200 µg/mL CPE for 24 hr. CPE at various concentrations (0-200 µg/mL) markedly decreased AGS cell viability and increased apoptotic cell death dose and time dependently. CPE increased the levels of cleaved caspase-8, -7, -3, and poly (ADP-ribose) polymerase in a dose-dependent manner but not cleaved caspase-9. CPE exerted no effects on Bcl-2 and Bax levels. The level of X-linked inhibitor of apoptosis protein decreased within a narrow range following CPE treatment. The levels of Trail, DR4, and Fas-L increased dose-dependently in CPE-treated AGS cells. These results show that CPE decreases growth and induces apoptosis in AGS gastric cancer cells and that activation of the death receptor pathway contributes to CPE-induced apoptosis in AGS cells. In conclusion, CPE had more of an effect on gastric cancer cells than breast or prostate cancer cells, suggesting that chestnuts would have a positive effect against gastric cancer.