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Sample records for ag samples show

  1. File list: Unc.Kid.20.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Kid.20.AllAg.Nephrectomy_sample hg19 Unclassified Kidney Nephrectomy sample htt...p://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Kid.20.AllAg.Nephrectomy_sample.bed ...

  2. File list: DNS.Kid.20.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Kid.20.AllAg.Nephrectomy_sample hg19 DNase-seq Kidney Nephrectomy sample http:/.../dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/DNS.Kid.20.AllAg.Nephrectomy_sample.bed ...

  3. File list: DNS.Kid.50.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Kid.50.AllAg.Nephrectomy_sample hg19 DNase-seq Kidney Nephrectomy sample http:/.../dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/DNS.Kid.50.AllAg.Nephrectomy_sample.bed ...

  4. File list: DNS.Kid.05.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Kid.05.AllAg.Nephrectomy_sample hg19 DNase-seq Kidney Nephrectomy sample http:/.../dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/DNS.Kid.05.AllAg.Nephrectomy_sample.bed ...

  5. File list: Unc.Kid.10.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Kid.10.AllAg.Nephrectomy_sample hg19 Unclassified Kidney Nephrectomy sample htt...p://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Kid.10.AllAg.Nephrectomy_sample.bed ...

  6. File list: Pol.Kid.50.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Kid.50.AllAg.Nephrectomy_sample hg19 RNA polymerase Kidney Nephrectomy sample h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Kid.50.AllAg.Nephrectomy_sample.bed ...

  7. File list: Unc.Kid.50.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Kid.50.AllAg.Nephrectomy_sample hg19 Unclassified Kidney Nephrectomy sample htt...p://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Kid.50.AllAg.Nephrectomy_sample.bed ...

  8. File list: Pol.Kid.05.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Kid.05.AllAg.Nephrectomy_sample hg19 RNA polymerase Kidney Nephrectomy sample h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Kid.05.AllAg.Nephrectomy_sample.bed ...

  9. File list: Pol.Dig.50.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Dig.50.AllAg.Gastric_primary_sample hg19 RNA polymerase Digestive tract Gastric... primary sample http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Dig.50.AllAg.Gastric_primary_sample.bed ...

  10. File list: Pol.Dig.20.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Dig.20.AllAg.Gastric_primary_sample hg19 RNA polymerase Digestive tract Gastric... primary sample http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Dig.20.AllAg.Gastric_primary_sample.bed ...

  11. File list: DNS.Dig.50.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Dig.50.AllAg.Gastric_primary_sample hg19 DNase-seq Digestive tract Gastric prim...ary sample SRX201807,SRX201812 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/DNS.Dig.50.AllAg.Gastric_primary_sample.bed ...

  12. File list: Pol.Dig.05.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Dig.05.AllAg.Gastric_primary_sample hg19 RNA polymerase Digestive tract Gastric... primary sample http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Dig.05.AllAg.Gastric_primary_sample.bed ...

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

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.50.AllAg.Gastric_primary_sample hg19 TFs and others Digestive tract Gastric... primary sample http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Dig.50.AllAg.Gastric_primary_sample.bed ...

  14. File list: Unc.Dig.05.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Dig.05.AllAg.Gastric_primary_sample hg19 Unclassified Digestive tract Gastric p...rimary sample http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Dig.05.AllAg.Gastric_primary_sample.bed ...

  15. File list: Unc.Dig.50.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Dig.50.AllAg.Gastric_primary_sample hg19 Unclassified Digestive tract Gastric p...rimary sample http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Dig.50.AllAg.Gastric_primary_sample.bed ...

  16. File list: Oth.Dig.05.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.05.AllAg.Gastric_primary_sample hg19 TFs and others Digestive tract Gastric... primary sample http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Dig.05.AllAg.Gastric_primary_sample.bed ...

  17. File list: DNS.Dig.05.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Dig.05.AllAg.Gastric_primary_sample hg19 DNase-seq Digestive tract Gastric prim...ary sample SRX201807,SRX201812 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/DNS.Dig.05.AllAg.Gastric_primary_sample.bed ...

  18. File list: DNS.Dig.20.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Dig.20.AllAg.Gastric_primary_sample hg19 DNase-seq Digestive tract Gastric prim...ary sample SRX201807,SRX201812 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/DNS.Dig.20.AllAg.Gastric_primary_sample.bed ...

  19. File list: DNS.Dig.10.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Dig.10.AllAg.Gastric_primary_sample hg19 DNase-seq Digestive tract Gastric prim...ary sample SRX201807,SRX201812 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/DNS.Dig.10.AllAg.Gastric_primary_sample.bed ...

  20. File list: Unc.Dig.20.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Dig.20.AllAg.Gastric_primary_sample hg19 Unclassified Digestive tract Gastric p...rimary sample http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Dig.20.AllAg.Gastric_primary_sample.bed ...

  1. File list: Oth.Dig.20.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.20.AllAg.Gastric_primary_sample hg19 TFs and others Digestive tract Gastric... primary sample http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Dig.20.AllAg.Gastric_primary_sample.bed ...

  2. File list: Oth.Dig.10.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.10.AllAg.Gastric_primary_sample hg19 TFs and others Digestive tract Gastric... primary sample http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Dig.10.AllAg.Gastric_primary_sample.bed ...

  3. File list: Pol.Dig.10.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Dig.10.AllAg.Gastric_primary_sample hg19 RNA polymerase Digestive tract Gastric... primary sample http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Dig.10.AllAg.Gastric_primary_sample.bed ...

  4. File list: NoD.Kid.10.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Kid.10.AllAg.Nephrectomy_sample hg19 No description Kidney Nephrectomy sample h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/NoD.Kid.10.AllAg.Nephrectomy_sample.bed ...

  5. File list: InP.Kid.10.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Kid.10.AllAg.Nephrectomy_sample hg19 Input control Kidney Nephrectomy sample SR...90,SRX1037589,SRX1037588,SRX1037582 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.Kid.10.AllAg.Nephrectomy_sample.bed ...

  6. File list: InP.Kid.50.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Kid.50.AllAg.Nephrectomy_sample hg19 Input control Kidney Nephrectomy sample SR...84,SRX1037589,SRX1037590,SRX1037583 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.Kid.50.AllAg.Nephrectomy_sample.bed ...

  7. File list: His.Kid.50.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Kid.50.AllAg.Nephrectomy_sample hg19 Histone Kidney Nephrectomy sample SRX95646...X1037580,SRX1037579,SRX956473 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Kid.50.AllAg.Nephrectomy_sample.bed ...

  8. File list: His.Kid.05.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Kid.05.AllAg.Nephrectomy_sample hg19 Histone Kidney Nephrectomy sample SRX95646...1037579,SRX1037580,SRX1037585 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Kid.05.AllAg.Nephrectomy_sample.bed ...

  9. File list: His.Kid.10.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Kid.10.AllAg.Nephrectomy_sample hg19 Histone Kidney Nephrectomy sample SRX95646...1037587,SRX1037586,SRX1037580 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Kid.10.AllAg.Nephrectomy_sample.bed ...

  10. File list: InP.Kid.20.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Kid.20.AllAg.Nephrectomy_sample hg19 Input control Kidney Nephrectomy sample SR...83,SRX1037590,SRX1037588,SRX1037582 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.Kid.20.AllAg.Nephrectomy_sample.bed ...

  11. File list: His.Kid.20.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Kid.20.AllAg.Nephrectomy_sample hg19 Histone Kidney Nephrectomy sample SRX95646...1037587,SRX1037580,SRX1037579 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Kid.20.AllAg.Nephrectomy_sample.bed ...

  12. File list: Oth.Kid.10.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Kid.10.AllAg.Nephrectomy_sample hg19 TFs and others Kidney Nephrectomy sample h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Kid.10.AllAg.Nephrectomy_sample.bed ...

  13. File list: Oth.Kid.20.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Kid.20.AllAg.Nephrectomy_sample hg19 TFs and others Kidney Nephrectomy sample h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Kid.20.AllAg.Nephrectomy_sample.bed ...

  14. File list: NoD.Kid.20.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Kid.20.AllAg.Nephrectomy_sample hg19 No description Kidney Nephrectomy sample h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/NoD.Kid.20.AllAg.Nephrectomy_sample.bed ...

  15. File list: Oth.Kid.05.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Kid.05.AllAg.Nephrectomy_sample hg19 TFs and others Kidney Nephrectomy sample h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Kid.05.AllAg.Nephrectomy_sample.bed ...

  16. File list: Oth.Kid.50.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Kid.50.AllAg.Nephrectomy_sample hg19 TFs and others Kidney Nephrectomy sample h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Kid.50.AllAg.Nephrectomy_sample.bed ...

  17. File list: InP.Kid.05.AllAg.Nephrectomy_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Kid.05.AllAg.Nephrectomy_sample hg19 Input control Kidney Nephrectomy sample SR...84,SRX1037590,SRX1037588,SRX1037589 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.Kid.05.AllAg.Nephrectomy_sample.bed ...

  18. File list: His.Dig.05.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Dig.05.AllAg.Gastric_primary_sample hg19 Histone Digestive tract Gastric primar...105,SRX369094,SRX369095 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Dig.05.AllAg.Gastric_primary_sample.bed ...

  19. File list: His.Dig.20.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Dig.20.AllAg.Gastric_primary_sample hg19 Histone Digestive tract Gastric primar...096,SRX369094,SRX369095 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Dig.20.AllAg.Gastric_primary_sample.bed ...

  20. File list: His.Dig.10.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Dig.10.AllAg.Gastric_primary_sample hg19 Histone Digestive tract Gastric primar...095,SRX369094,SRX369099 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Dig.10.AllAg.Gastric_primary_sample.bed ...

  1. Amperometric detection of Sudan I in red chili powder samples using Ag nanoparticles decorated graphene oxide modified glassy carbon electrode.

    Science.gov (United States)

    Prabakaran, E; Pandian, K

    2015-01-01

    A simple and sensitive electrochemical method was developed to determine the concentration of Sudan I in chili powder based on silver nanoparticles decorated graphene oxide modified glassy carbon electrode (AgNPs@GO/GCE). The voltammetry behaviour of Sudan I on modified GCE was investigated in phosphate buffer medium (PBS) with various pH ranges and the electron transfer properties were studied. It is found that the AgNPs@GO/GCE can catalyse the reduction of azo group, -N=N- followed by electrochemical oxidation of (-)OH group present in Sudan I dye molecule. Quantitative detection of Sudan I present in food products was carried out by amperometry method in which reduction potential was fixed at -0.77 V vs. Ag/AgCl. The amperometry method showed an excellent performance with a sensitivity of 6.83 μA mM(-1) and a detection limit of 11.4 × 10(-7)ML(-1). A linear calibration graph was constructed in the ranging 3.90 × 10(-6) to 3.19 × 10(-5)ML(-1). The method was successfully applied for the determination of Sudan I in red chili powder samples.

  2. File list: InP.Dig.10.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Dig.10.AllAg.Gastric_primary_sample hg19 Input control Digestive tract Gastric ...369082 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.Dig.10.AllAg.Gastric_primary_sample.bed ...

  3. File list: NoD.Dig.50.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Dig.50.AllAg.Gastric_primary_sample hg19 No description Digestive tract Gastric...X190784,SRX270966,SRX190796,SRX136952 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/NoD.Dig.50.AllAg.Gastric_primary_sample.bed ...

  4. File list: InP.Dig.20.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Dig.20.AllAg.Gastric_primary_sample hg19 Input control Digestive tract Gastric ...369070 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.Dig.20.AllAg.Gastric_primary_sample.bed ...

  5. File list: NoD.Dig.05.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Dig.05.AllAg.Gastric_primary_sample hg19 No description Digestive tract Gastric...X136952,SRX136976,SRX347263,SRX190796 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/NoD.Dig.05.AllAg.Gastric_primary_sample.bed ...

  6. File list: NoD.Dig.10.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Dig.10.AllAg.Gastric_primary_sample hg19 No description Digestive tract Gastric...X347274,SRX347263,SRX190796,SRX270966 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/NoD.Dig.10.AllAg.Gastric_primary_sample.bed ...

  7. File list: NoD.Dig.20.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Dig.20.AllAg.Gastric_primary_sample hg19 No description Digestive tract Gastric...X347263,SRX190784,SRX270966,SRX190796 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/NoD.Dig.20.AllAg.Gastric_primary_sample.bed ...

  8. File list: InP.Dig.50.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Dig.50.AllAg.Gastric_primary_sample hg19 Input control Digestive tract Gastric ...369070 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.Dig.50.AllAg.Gastric_primary_sample.bed ...

  9. File list: InP.Dig.05.AllAg.Gastric_primary_sample [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Dig.05.AllAg.Gastric_primary_sample hg19 Input control Digestive tract Gastric ...369082 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.Dig.05.AllAg.Gastric_primary_sample.bed ...

  10. Occupied and unoccupied band structure of Ag(100) determined by photoemission from Ag quantum wells and bulk samples

    International Nuclear Information System (INIS)

    Angle-resolved photoemission spectra taken from atomically uniform films of Ag on Fe(100) show layer-resolved quantum-well peaks. The measured peak positions as a function of film thickness permit a unique determination of the initial band dispersion via the Bohr-Sommerfeld quantization rule. This information, combined with normal-emission data taken from a single crystal Ag(100), leads to a unique determination of the final band dispersion. In this study, we employ a two-band model with four adjustable parameters for a simultaneous fit to these experimental results. The initial and final band dispersions deduced from the fit are accurate to better than 0.03 eV at any wave vector k within the range of measurement. The analytic formula for the band dispersions and the parameters for the best fit are given for future reference. The Fermi wave vector along [100], normalized to the Brillouin-zone size, is determined to be kF/kΓX=0.828±0.001, which is more accurate than the de Haas-van Alphen result. The corresponding Fermi velocity is νF=1.06 in units of the free-electron value. The combined reflection phase for the electron wave at the two boundaries is also deduced and compared with a semiempirical formula. This comparison allows us to deduce the edges of the hybridization gap in the Fe substrate. (c) 2000 The American Physical Society

  11. Ag2S/CdS/TiO2 Nanotube Array Films with High Photocurrent Density by Spotting Sample Method

    OpenAIRE

    Sun, Hong; Zhao, Peini; Zhang, Fanjun; Liu, Yuliang; Hao, Jingcheng

    2015-01-01

    Ag2S/CdS/TiO2 hybrid nanotube array films (Ag2S/CdS/TNTs) were prepared by selectively depositing a narrow-gap semiconductor—Ag2S (0.9 eV) quantum dots (QDs)—in the local domain of the CdS/TiO2 nanotube array films by spotting sample method (SSM). The improvement of sunlight absorption ability and photocurrent density of titanium dioxide (TiO2) nanotube array films (TNTs) which were obtained by anodic oxidation method was realized because of modifying semiconductor QDs. The CdS/TNTs, Ag2S/TNT...

  12. Selective and sensitive optical chemosensor for detection of Ag(I) ions based on 2(4-hydroxy pent-3-en-2-ylideneamine) phenol in aqueous samples.

    Science.gov (United States)

    Mirzaei, Mohammad; Saeed, Jaber

    2011-11-01

    A selective and sensitive chemosensor, based on the 2(4-hydroxy pent-3-en-2-ylideneamine) phenol (HPYAP) as chromophore, has been developed for colorimetric and visual detection of Ag(I) ions. HPYAP shows a considerable chromogenic behavior toward Ag(I) ions by changing the color of the solution from pale-yellow to very chromatic-yellow, which can be easily detected with the naked-eye. The chemosensor exhibited selective absorbance enhancement to Ag(I) ions in water samples over other metal ions at 438 nm, with a linear range of 0.4-500 μM (r(2)=0.999) and a limit of detection 0.07 μM of Ag(I) ions with UV-vis spectrophotometer detection. The relative standard deviation (RSD) for 100 μM Ag(I) ions was 2.05% (n=7). The proposed method was applied for the determination Ag(I) ions in water and waste water samples.

  13. 23 CFR Appendix C to Subpart D of... - Sample Show Cause Rescission

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Sample Show Cause Rescission C Appendix C to Subpart D... Appendix C to Subpart D of Part 230—Sample Show Cause Rescission Certified Mail, Return Receipt Requested...-day show cause notice from this office for failing to implement the required contract...

  14. 23 CFR Appendix A to Subpart D of... - Sample Show Cause Notice

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Sample Show Cause Notice A Appendix A to Subpart D of... to Subpart D of Part 230—Sample Show Cause Notice Certified Mail, Return Receipt Requested Date... skilled categories of employees. The Department of Labor regulations (41 CFR 60) implementing...

  15. Solvent-dependent turn-on probe for dual monitoring of Ag+ and Zn2+ in living biological samples

    International Nuclear Information System (INIS)

    Highlights: • A solvent-dependent probe was presented for dual monitoring of Ag+ and Zn2+. • The probe exhibited special selectivity and sensitivity at physiological range. • The mechanism was investigated both experimentally and computationally. • The probe was highly suitable for mapping Ag+ and Zn2+ in biological samples. - Abstract: A novel, solvent-dependent “off–on” probe with benzoylthiourea moiety as the functional receptor and fluorescein as the fluorophore was designed for monitoring of Ag+ in EtOH–H2O (2:8, v/v) solution and Zn2+ in CH3CN–H2O (2:8, v/v) solution at physiological range with sufficient selectivity and sensitivity. The Ag+ promoted desulfurization of thiosemicarbazide functionality in formation of the 1,3,4-oxadiazole and the coordination of Zn2+ to the O atom and N atom of the spoirolactam moiety and the S atom of the benzoylthiourea moiety were investigated to be the power that promoted the fluorescent enhancement. This probe was tested highly suitable for mapping Ag+ and Zn2+ in living human osteosarcoma MG-63 cells and microbial cell–EPS–mineral aggregates, thus, providing a wonderful candidate for tracking Ag+ and Zn2+ in biological organisms and processes

  16. Hydrophobic dipeptide crystals: a promising Ag-free class of ultramicroporous materials showing argon/oxygen adsorption selectivity.

    Science.gov (United States)

    Afonso, R; Mendes, A; Gales, L

    2014-09-28

    The adsorption isotherms of nitrogen, oxygen and argon in four VA-class hydrophobic dipeptides are presented. Isotherms were determined at 5, 20 and 35 °C, for a pressure range of 0-6 bar. Under these conditions, adsorption is still in the Henry region. For all materials and temperatures, the sequence of preferential adsorption is Ar > O2 > N2, a highly abnormal result. At 5 °C, the dipeptide with the smallest pores, VI, has Ar/O2 adsorption equilibrium selectivities up to 1.30, the highest ever measured in Ag-free adsorbents. Gas uptakes, at 1 bar and 20 °C, are ∼0.05 mol kg(-1), very low relative values that are partially explained by the low porosity of the solids (materials for the process of O2 generation by pressure swing adsorption (PSA) is discussed. The results indicate some of the structural and chemical properties that prospective Ag-free adsorbents should have in order to have Ar/O2 selectivity, hydrophobic pores, less than 0.5 nm-wide, and porosity of, at least, 20%.

  17. The selective VEGFR1-3 inhibitor axitinib (AG-013736) shows antitumor activity in human neuroblastoma xenografts.

    Science.gov (United States)

    Rössler, Jochen; Monnet, Yann; Farace, Francoise; Opolon, Paule; Daudigeos-Dubus, Estelle; Bourredjem, Abderrahmane; Vassal, Gilles; Geoerger, Birgit

    2011-06-01

    Tumor angiogenesis in childhood neuroblastoma is an important prognostic factor suggesting a potential role for antiangiogenic agents in the treatment of high-risk disease. Within the KidsCancerKinome project, we evaluated the new oral selective pan-VEGFR tyrosine kinase inhibitor axitinib (AG-013736) against neuroblastoma cell lines and the subcutaneous and orthotopic xenograft model IGR-N91 derived from a primary bone marrow metastasis. Axitinib reduced cell proliferation in a dose-dependent manner with IC(50) doses between 274 and >10,000 nmol/l. Oral treatment with 30 mg/kg BID for 2 weeks in advanced tumors yielded significant tumor growth delay, with a median time to reach five times initial tumor volume of 11.4 days compared to controls (p = 0.0006) and resulted in significant reduction in bioluminescence. Simultaneous inhibition of VEGFR downstream effector mTOR using rapamycin 20 mg/kg q2d×5 did not statistically enhance tumor growth delay compared to single agent activities. Axitinib downregulated VEGFR-2 phosphorylation resulting in significantly decreased microvessel density (MVD) and overall surface fraction of tumor vessels (OSFV) in all xenografts as measured by CD34 immunohistochemical staining (mean MVD ± SD and OSFV at 14 days 21.27 ± 10.03 in treated tumors vs. 48.79 ± 17.27 in controls and 0.56% vs. 1.29%; p = 0.0006, respectively). We further explored the effects of axitinib on circulating mature endothelial cells (CECs) and endothelial progenitor cells (CEPs) measured by flow cytometry. While only transient modification was observed for CECs, CEP counts were significantly reduced during and up to 14 days after end of treatment. Axitinib has potent antiangiogenic properties that may warrant further evaluation in neuroblastoma. PMID:20715103

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

    Science.gov (United States)

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

    2014-02-01

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

  19. 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

  20. Polygenic Scores Predict Alcohol Problems in an Independent Sample and Show Moderation by the Environment

    Directory of Open Access Journals (Sweden)

    Jessica E. Salvatore

    2014-04-01

    Full Text Available Alcohol problems represent a classic example of a complex behavioral outcome that is likely influenced by many genes of small effect. A polygenic approach, which examines aggregate measured genetic effects, can have predictive power in cases where individual genes or genetic variants do not. In the current study, we first tested whether polygenic risk for alcohol problems—derived from genome-wide association estimates of an alcohol problems factor score from the age 18 assessment of the Avon Longitudinal Study of Parents and Children (ALSPAC; n = 4304 individuals of European descent; 57% female—predicted alcohol problems earlier in development (age 14 in an independent sample (FinnTwin12; n = 1162; 53% female. We then tested whether environmental factors (parental knowledge and peer deviance moderated polygenic risk to predict alcohol problems in the FinnTwin12 sample. We found evidence for both polygenic association and for additive polygene-environment interaction. Higher polygenic scores predicted a greater number of alcohol problems (range of Pearson partial correlations 0.07–0.08, all p-values ≤ 0.01. Moreover, genetic influences were significantly more pronounced under conditions of low parental knowledge or high peer deviance (unstandardized regression coefficients (b, p-values (p, and percent of variance (R2 accounted for by interaction terms: b = 1.54, p = 0.02, R2 = 0.33%; b = 0.94, p = 0.04, R2 = 0.30%, respectively. Supplementary set-based analyses indicated that the individual top single nucleotide polymorphisms (SNPs contributing to the polygenic scores were not individually enriched for gene-environment interaction. Although the magnitude of the observed effects are small, this study illustrates the usefulness of polygenic approaches for understanding the pathways by which measured genetic predispositions come together with environmental factors to predict complex behavioral outcomes.

  1. 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.

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

    Science.gov (United States)

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

    2006-03-01

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

  3. 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.

  4. Preoperative tumor localization of primary hyperparathyroidism. Comprehensive study of ultrasonography (US), scintigraphy (RI), arteriography (AG) and venous sampling (VS)

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Yutaka; Shinohara, Masahiro; Ito, Kazuo; Imamura, Fumimoto; Kasai, Yoichi (Hokkaido Univ., Sapporo (Japan). School of Medicine); Ishizuka, Reiki

    1983-02-01

    The diagnostic rate of each methods were discussed in thirty six cases and the following conclusions were made. (1.) The diagnostic rate of US, RI, AG and VS was 64.7%, 50%, 57.9%, 60.7% respectively. (2.) Ultrasonography and subtruction-scintigraphy were useful for screening examination for localization of parathyroid tumor. (3.) The reasonable diagnostic procedures were as follows: (1) In the cases of palpable, reno-uretrolithiasic type, and biochemical type: US ..-->.. RI ..-->.. VS. (2) In the cases of nonpalpable osteolytic type, and previous neck surgery: US ..-->.. RI ..-->.. AG ..-->.. VS. These results indicate that the systemic diagnoses are useful to predict localization of parathyroid tumors.

  5. 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.

  6. 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.).

  7. Decay of linkage disequilibrium within genes across HGDP-CEPH human samples: most population isolates do not show increased LD

    Directory of Open Access Journals (Sweden)

    Navarro Arcadi

    2009-07-01

    Full Text Available Abstract Background It is well known that the pattern of linkage disequilibrium varies between human populations, with remarkable geographical stratification. Indirect association studies routinely exploit linkage disequilibrium around genes, particularly in isolated populations where it is assumed to be higher. Here, we explore both the amount and the decay of linkage disequilibrium with physical distance along 211 gene regions, most of them related to complex diseases, across 39 HGDP-CEPH population samples, focusing particularly on the populations defined as isolates. Within each gene region and population we use r2 between all possible single nucleotide polymorphism (SNP pairs as a measure of linkage disequilibrium and focus on the proportion of SNP pairs with r2 greater than 0.8. Results Although the average r2 was found to be significantly different both between and within continental regions, a much higher proportion of r2 variance could be attributed to differences between continental regions (2.8% vs. 0.5%, respectively. Similarly, while the proportion of SNP pairs with r2 > 0.8 was significantly different across continents for all distance classes, it was generally much more homogenous within continents, except in the case of Africa and the Americas. The only isolated populations with consistently higher LD in all distance classes with respect to their continent are the Kalash (Central South Asia and the Surui (America. Moreover, isolated populations showed only slightly higher proportions of SNP pairs with r2 > 0.8 per gene region than non-isolated populations in the same continent. Thus, the number of SNPs in isolated populations that need to be genotyped may be only slightly less than in non-isolates. Conclusion The "isolated population" label by itself does not guarantee a greater genotyping efficiency in association studies, and properties other than increased linkage disequilibrium may make these populations interesting in

  8. Recidivism in female offenders: PCL-R lifestyle factor and VRAG show predictive validity in a German sample.

    Science.gov (United States)

    Eisenbarth, Hedwig; Osterheider, Michael; Nedopil, Norbert; Stadtland, Cornelis

    2012-01-01

    A clear and structured approach to evidence-based and gender-specific risk assessment of violence in female offenders is high on political and mental health agendas. However, most data on the factors involved in risk-assessment instruments are based on data of male offenders. The aim of the present study was to validate the use of the Psychopathy Checklist Revised (PCL-R), the HCR-20 and the Violence Risk Appraisal Guide (VRAG) for the prediction of recidivism in German female offenders. This study is part of the Munich Prognosis Project (MPP). It focuses on a subsample of female delinquents (n = 80) who had been referred for forensic-psychiatric evaluation prior to sentencing. The mean time at risk was 8 years (SD = 5 years; range: 1-18 years). During this time, 31% (n = 25) of the female offenders were reconvicted, 5% (n = 4) for violent and 26% (n = 21) for non-violent re-offenses. The predictive validity of the PCL-R for general recidivism was calculated. Analysis with receiver-operating characteristics revealed that the PCL-R total score, the PCL-R antisocial lifestyle factor, the PCL-R lifestyle factor and the PCL-R impulsive and irresponsible behavioral style factor had a moderate predictive validity for general recidivism (area under the curve, AUC = 0.66, p = 0.02). The VRAG has also demonstrated predictive validity (AUC = 0.72, p = 0.02), whereas the HCR-20 showed no predictive validity. These results appear to provide the first evidence that the PCL-R total score and the antisocial lifestyle factor are predictive for general female recidivism, as has been shown consistently for male recidivists. The implications of these findings for crime prevention, prognosis in women, and future research are discussed.

  9. Negative Temperature Coefficient of Resistivity in Bulk Nanostructured Ag

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@The change of the temperature coefficient of resistivity (α) with the particle size, dp, and the grain size, dc, in the nanostructured Ag bulk samples was investigated, dp and de were controlled by heating the nano-Ag powders over the temperature range from 393 to 453 K. The electrical resistance measurements of the nanostructured Ag bulk samples obtained by compacting the Ag powders after heat treatments showed a change in the sign of α with dp and dc. When dp and dc are smaller or equal to 18 and 11 nm below room temperature or 20 and 12 nm above room temperature, respectively, the sign of the temperature coefficient of resistivity changes from positive to negative. The negative α arises mainly from the high resistivity induced by the particle interfaces with very lowly ordered or even disordered structure, a large volume fraction of interfaces and impurities existing in the interfaces, and the quantum size effect appearing in the nano-Ag grains.

  10. Reduced Magnetization and Loss in Ag-Mg Sheathed Bi2212 Wires: Systematics With Sample Twist Pitch and Length

    International Nuclear Information System (INIS)

    Suppression of magnetization and effective filament diameter (deff) with twisting was investigated for a series of recent Bi2212 strands manufactured by Oxford Superconducting Technologies. We measured magnetization as a function of field (out to 14 T), at 5.1 K, of twisted and nontwisted 37 x 18 double restack design strands. The samples were helical coils 5-6 mm in height and approximately 5 mm in diameter. The strand diameter was 0.8 mm. The magnetization of samples having twist pitches of 25.4, 12.7, and 6.35 mm were examined and compared to nontwisted samples of the same filament configuration. The critical state model was used to extract the 12-T deff from magnetization data for comparison. Twisting the samples reduced deff by a factor of 1.5-3. The deff was shown to increase both with L and Lp. Mathematical expressions, based upon the anisotropic continuum model, were fit to the data, and a parameter γ2, which quantifies the electrical connectivity perpendicular to the filament axis, was extracted. The bundle-to-bundle connectivity along the radial axis was found to be approximately 0.2%. The deff was substantially reduced with Lp. In addition, the importance of understanding sample length dependence for quantitative measurements is discussed

  11. 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.

  12. Two different mechanisms on UV emission enhancement in Ag-doped ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Linhua, E-mail: congyu3256@tom.com [School of Physics and Optoelectronic Engineering, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Optics and Photonic Technology Laboratory, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Zheng, Gaige; Zhao, Lilong; Pei, Shixin [School of Physics and Optoelectronic Engineering, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Optics and Photonic Technology Laboratory, Nanjing University of Information Science and Technology, Nanjing 210044 (China)

    2015-02-15

    Ag-doped ZnO thin films were prepared by a sol–gel method. The structural, morphological and optical properties of the samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV–vis and photoluminescence spectra. The results show that the Ag in the ZnO thin films annealed at 500 °C for 1 h substitutes for Zn and exists in the form of Ag{sup +} ion (Ag{sub Zn}) while the Ag in the ZnO thin films without a post-annealing mainly exists in the form of simple substance (Ag{sup 0}). The incorporation of Ag indeed can improve the ultraviolet emission of ZnO thin films and suppress the visible emissions at the same time. However, the mechanisms on the ultraviolet emission enhancement in the annealed and unannealed Ag-doped ZnO thin films are very different. As for the post-annealed Ag-doped ZnO thin films, the UV emission enhancement maybe mainly results from more electron–hole pairs (excitons) due to Ag-doping while for the unannealed Ag-doped ZnO thin films; the UV emission enhancement is attributed to the resonant coupling between exciton emission in ZnO and localized surface plasmon in Ag nanoparticles. - Highlights: • Ag-doped ZnO thin films have been prepared by the sol–gel method. • Ag-doping can enhance ultraviolet emission of ZnO thin films and depress the visible emissions at the same time. • There are two different mechanisms on UV emission enhancement in Ag-doped ZnO thin films. • The UV emission enhancement from the resonant coupling between excitonic emissions and localized surface plasmon in Ag nanoparticle is very attractive.

  13. Modification of polyamide-CdS-CdSe composite material films with Ag using a cation–cation exchange reaction

    Energy Technology Data Exchange (ETDEWEB)

    Krylova, V.; Žalenkienė, S.; Dukstienė, N. [Department of Physical and Inorganic Chemistry, Kaunas University of Technology, Radvilenu st. 19, LT-50254, Kaunas (Lithuania); Baltrusaitis, J., E-mail: job314@lehigh.edu [Department of Chemical and Biomolecular Engineering, Lehigh University, B336 Iacocca Hall, 111 Research Drive, Bethlehem, PA 18015 (United States)

    2015-10-01

    Highlights: • We investigated deposition of a mixed CdSe-CdS-Ag{sub 2}Se-Ag{sub 2}S on polyamide. • A single chalcogen precursor – K{sub 2}SeS{sub 2}O{sub 6} – was used. • AAS showed five- to ten-fold excess of chalcogens diffused into PA. • Addition of AgNO{sub 3} resulted in subsurface Ag{sub 2}Se–Ag{sub 2}S formation. - Abstract: Thin mixed CdSe-CdS-Ag{sub 2}Se-Ag{sub 2}S films were deposited on a polyamide 6 (PA) surface by successfully using a cation-exchange reaction between Cd{sup 2+} and Ag{sup +} to convert CdSe-CdS into Ag{sub 2}Se-Ag{sub 2}S. These were deposited using a K{sub 2}SeS{sub 2}O{sub 6} precursor solution at 60 °C followed by cadmium acetate (Cd(CH{sub 3}COO){sub 2}). An aqueous AgNO{sub 3} solution was used as the Ag source. XRD patterns showed a complex PA-Cd-S-Se-Ag film crystalline composition with CdS, CdSe, Ag{sub 2}S and Ag{sub 2}Se peaks. Calculated dislocation density ranged within 5–15 × 10{sup 13} lines·m{sup −2} indicating high quality atomic layers. Atomic Absorption Spectroscopy (AAS) showed five- to ten-fold excess of chalcogens to metals in the thin films formed. No chalcogenides were observed on the sample surface during XPS analysis after Ag exchange due to the desorption of CdS and CdSe layers, not diffused into the bulk of the polymer suggesting that silver chalcogenides were located subsurface, as opposed to the outermost layer, likely comprised of Ag{sub 2}O.

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

    Science.gov (United States)

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

    2015-05-01

    Separation of carrier-free iodine from low-level iodine samples and accurate measurement of ultra-low-level 129I in microgram iodine target are essential but a bottleneck in geology and environment research using naturally produced 129I. This article presents a detection technique of accelerator 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 and electrically conductive matrix to be mixed with AgI-AgCl powder, in order to obtain and maintain a stable and high iodine ion current intensity, as well as less memory effect and low background level of 129I. The most optimal ratio of the Nb matrix to the AgI-AgCl powder was found to be 5:1 by mass. The typical current of 127I5+ using AgI-AgCl targets with iodine content from 5 to 80 μg was measured to be 5 to 100 nA. Four-year AMS measurements of the 129I/127I ratios in standards of low iodine content and the machine blanks showed a good repeatability and stability.

  15. Accelerator mass spectrometry analysis of ultra-low-level (129)I in carrier-free AgI-AgCl sputter targets.

    Science.gov (United States)

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

    2015-05-01

    Separation of carrier-free iodine from low-level iodine samples and accurate measurement of ultra-low-level (129)I in microgram iodine target are essential but a bottleneck in geology and environment research using naturally produced (129)I. This article presents a detection technique of accelerator mass spectrometry (AMS) for accurate determination of ultra-low-level (129)I 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 and electrically conductive matrix to be mixed with AgI-AgCl powder, in order to obtain and maintain a stable and high iodine ion current intensity, as well as less memory effect and low background level of (129)I. The most optimal ratio of the Nb matrix to the AgI-AgCl powder was found to be 5:1 by mass. The typical current of (127)I(5+) using AgI-AgCl targets with iodine content from 5 to 80 μg was measured to be 5 to 100 nA. Four-year AMS measurements of the (129)I/(127)I ratios in standards of low iodine content and the machine blanks showed a good repeatability and stability. PMID:25743113

  16. [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.

  17. (RE)BaCuO/Ag Composites: The Role of Silver in Bulk Materials and Joints

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    We have investigated the phase equilibria in (RE)BaCuO/Ag systems, the influence of Ag on the processing of (RE)BaCuO/Ag composites and the resulting properties. YBaCuO/Ag composites have been grown by the modified melt crystallization process with YBa2Cu3O7, Y2O3, Pt and Ag2O in the precursor. The improved strength of the YBaCuO/Ag composites compared with the conventional YBaCuO bulk material permitted us to magnetize these materials to achieve trapped fields up to 16 T (at 24 K) in the gap of a mini-magnet. The investigation of the microstructure revealed a remarkable increase of the spacing between micro-cracks especially of those perpendicular to a/b-planes when 12 wt% Ag was added. In the case of SmBaCuO/Ag composites, Ag has a strong influence on processing and causes interactions between RE123 seeds and the sample. We show the growth of single-grain SmBaCuO/Ag composites in air and discuss the influence of post-annealing on increasing Tc and Jc. Furthermore, YBaCuO/Ag composites have been shown to be appropriate materials used as a solder to join large single grains to large arrays or to "repair" grain boundaries in arrays grown by a multiseeding technique.

  18. Studies on properties of Ag/Co0.05Ti0.95O2 random nanocomposite as metamaterials

    Science.gov (United States)

    Khorshidi, Zahra; Gholipur, Reza; Bahari, Ali

    2016-10-01

    In this work, random metal-dielectric nanocomposites consisting of Ag nanorods embedded in Co0.05Ti0.95O2 are studied. The aspect ratio of Ag nanorods is about 15, and different contents of Ag nanorods are investigated. The nanocomposites with Ag content exceeding its percolation threshold, show metal-like behavior with negative permittivity. Moreover, in these nanocomposites, Ag nanorods form silver networks with diamagnetic response which combine with the magnetic resonance of ferromagnetic Co0.05Ti0.95O2 particles. The permeability spectra show that CTO-Ag15 33% nanocomposite has strongest diamagnetic behavior. These results indicate that the CTO-Ag15 33% sample is a promising candidate for the double negative materials.

  19. Sampling

    CERN Document Server

    Thompson, Steven K

    2012-01-01

    Praise for the Second Edition "This book has never had a competitor. It is the only book that takes a broad approach to sampling . . . any good personal statistics library should include a copy of this book." —Technometrics "Well-written . . . an excellent book on an important subject. Highly recommended." —Choice "An ideal reference for scientific researchers and other professionals who use sampling." —Zentralblatt Math Features new developments in the field combined with all aspects of obtaining, interpreting, and using sample data Sampling provides an up-to-date treat

  20. 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.

  1. Oil-in-Water Self-Assembled Synthesis of Ag@AgCl Nano-Particles on Flower-like Bi2O2CO3 with Enhanced Visible-Light-Driven Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Shuanglong Lin

    2016-06-01

    Full Text Available In this work, a series of novel flower-like Ag@AgCl/Bi2O2CO3 were prepared by simple and feasible oil-in-water self-assembly processes. The phase structures of as-prepared samples were examined by X-ray diffraction (XRD, Scanning electron microscopy (SEM, Transmission electron microscopy (TEM, UV-vis diffuse reflectance spectroscopy (DRS, X-ray fluorescence spectrometer (XRF, etc. The characterization results indicated that the presence of Ag@AgCl did not affect the crystal structure, but exerted a great influence on the photocatalytic activity of Bi2O2CO3 and enhanced the absorption band of pure Bi2O2CO3. The photocatalytic activities of the Ag@AgCl/Bi2O2CO3 samples were determined by photocatalytic degradation of methylene blue (MB under visible light irradiation. The Ag@AgCl (10 wt %/Bi2O2CO3 composite showed the highest photocatalytic activity, degrading 97.9% MB after irradiation for 20 min, which is over 1.64 and 3.66 times faster than that of pure Ag@AgCl (calculated based on the equivalent Ag@AgCl content in Ag@AgCl (10 wt %/Bi2O2CO3 and pure Bi2O2CO3, respectively. Bisphenol A (BPA was also degraded to further prove the degradation ability of Ag@AgCl/Bi2O2CO3. Photocurrent studies indicated that the recombination of photo-generated electron–hole pairs was decreased effectively due to the formation of heterojunctions between flower-like Bi2O2CO3 and Ag@AgCl nanoparticles. Trapping experiments indicated that O2−, h+ and Cl° acted as the main reactive species for MB degradation in the present photocatalytic system. Furthermore, the cycling experiments revealed the good stability of Ag@AgCl/Bi2O2CO3 composites. Based on the above, a photocatalytic mechanism for the degradation of organic compounds over Ag@AgCl/Bi2O2CO3 was proposed.

  2. Ag layer thickness dependence of magnetic properties in Fe/Ag superlattices

    International Nuclear Information System (INIS)

    The magnetic properties of [Fe(20 A)/Ag(t)]20 superlattices with Ag film thickness varying from 7 to 20 A, prepared by molecular beam epitaxy on (0 0 1)MgO substrate, are presented. The epitaxial growth and the quality of layered structure of the samples were controlled by RHEED and X-ray diffraction techniques. Magnetic hysteresis loops with the magnetic field applied parallel and perpendicular to the plane of the films were determined by vibrating sample magnetometer and superconducting quantum interference device (SQUID) magnetometer at 4.2 K. Magnetotransport properties were measured by conventional DC four terminal method with the magnetic field applied parallel to the plane of the films at 4.2 K. The analysis of the hysteresis loops indicates an in plane easy magnetization axis and shows a dependence of the interface anisotropy on the Ag film thickness

  3. Enhanced visible-light photocatalytic performances of Ag3PO4 surface-modified with small amounts of TiO2 and Ag

    Science.gov (United States)

    Wang, Desong; Li, Lei; Luo, Qingzhi; An, Jing; Li, Xueyan; Yin, Rong; Zhao, Mangmang

    2014-12-01

    A novel approach has been developed to prepare an efficient visible-light photocatalyst using Ag3PO4 and TiO2 sol as precursors. First, Ag3PO4 particles were dipped into TiO2 sol for 5 min and were filtered quickly. Second, Ag3PO4 particles adsorbing a small amount of TiO2 sol were aged for 24 h to form TiO2 gel on their surface. Finally, Ag3PO4 particles covered by TiO2 gel were calcined at 450 °C for 2 h to obtain the surface-modified Ag3PO4 sample. The surface-modified Ag3PO4 was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, UV-vis diffuse reflection spectroscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. The visible-light photocatalytic performances of the surface-modified Ag3PO4 were evaluated by the photodegradation of methyl orange or phenol solution. The results showed that the surface-modified Ag3PO4 exhibited much higher visible-light photocatalytic activity and stability than pure Ag3PO4. As the amount of TiO2 gel on the Ag3PO4 surface increased, the visible-light photocatalytic activity increased first and then decreased. The surface-modification of Ag3PO4 obviously decreased its solubility in water environment due to the protection of TiO2 and Ag nanocrystals on the surface. The visible-light photocatalytic mechanism of the surface-modified Ag3PO4 has been discussed.

  4. Microstructural study of Y1Ba2Cu3O7-x/Ag samples irradiated with 60Co γ rays at high doses

    International Nuclear Information System (INIS)

    We have investigated the damage induced by irradiation in Y1Ba2Cu3O7-x silver added samples. The samples were prepared with 0 and 6.5 wt% of silver and irradiated by high-energy γ irradiation (50-150 Mrad). The roles of silver and dosage irradiation are discussed in terms of their effects on microstructure, crystallinity, critical temperature (Tc) and zero-resistance temperature (T0). After irradiation, Tc decreased while the room-temperature electrical resistance increased by a factor of 8 for some of the samples. The difference in T0 between irradiated and non-irradiated YBCO samples was of the order of 10 K. We have found that the difference is bigger for silver-added samples. We have also observed several changes in diffraction patterns of YBCO and YBCO-silver samples. SEM images, EDS and XPS analysis showed that silver resided inside the grains as single atoms and as metallic clusters. The relative concentrations of the elements in samples were quantified by Auger electron spectroscopy. The values showed a gradual increase for radiation doses ranging between 0 and 100 Mrad. For doses up to 100 Mrad, Jc decreased because of the weak-link breakage induced by high doses of γ rays. (author)

  5. Facile Preparation of Ag/NiO Composite Nanosheets and Their Antibacterial Activity

    Science.gov (United States)

    Shi, Cui-E.; Pan, Lu; Wang, Cheng-Run; He, Yi; Wu, Yong-Feng; Xue, Sai-Sai

    2016-01-01

    Sheet-like precursors of NiO and Ag/NiO with different Ag contents were synthesized by a facile and easily controlled hydrothermal method. The NiO and Ag/NiO composite nanosheets were prepared by calcination of the corresponding precursors at 400°C for 3 h. The as-synthesized samples were characterized by thermogravimetric analysis, x-ray diffraction, transmission electron microscopy, and scanning electron microscopy. The antibacterial activity of NiO and Ag/NiO composites to several gram-positive and gram-negative bacteria was examined. Results showed that NiO nanosheets hardly exhibited antibacterial activity; however, Ag/NiO composites displayed higher activity even with low Ag content.

  6. 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.

  7. 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.

  8. Enhanced photoelectrochemical performance of Ag-ZnO thin films synthesized by spray pyrolysis technique

    International Nuclear Information System (INIS)

    Highlights: → Synthesis of Ag-ZnO nanocomposites by spray pyrolysis technique. → Examine the effect of Ag doping on the structural, morphological optical, and photoelectrochemical properties. → Surface Plasmon Resonance phenomenon of the spray deposited Ag-ZnO nanocomposites. → Enhancement in photoelectrochemical performance of ZnO thin films after Ag doping. - Abstract: Silver doped zinc oxide (Ag-ZnO) thin films were deposited on glass and tin doped indium oxide (ITO) coated glass substrates by using pneumatic spray pyrolysis technique (SPT) at 450 deg. C from aqueous solutions of zinc acetate and silver nitrate precursors. The effect of silver doping on structural, morphological and optical properties of films was studied. The XRD spectra of the Ag-ZnO films indicate the polycrystalline nature having hexagonal crystal structure. SEM micrographs show the uniform distribution of spherical grains of about 80-90 nm grain size for the pure ZnO thin films. The Ag nanoparticles are clearly visualized in SEM images of Ag-ZnO samples. The optical band gap energy decreases as the percentage of silver doping increases. Surface Plasmon Resonance (SPR) related phenomena are observed and correlated to the optical properties of Ag-ZnO thin films. The overall photoelectrochemical (PEC) performance of the samples was investigated and discussed. Moreover, the samples are more photoactive as compare to the pure ZnO sample and the sample ZnOAg15 shows the highest current. The photocurrent increases upto 249 μA cm-2 and 303 μA cm-2 in visible light and in UV illumination, respectively, and then decreases as the Ag doping increases into the film.

  9. Synthesis, structural characterisation and antibacterial activity of Ag+-doped fluorapatite nanomaterials prepared by neutralization method

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • The neutralization method has been used for synthesis of silver-doped fluorapatite powders. • Particles of silver-doped fluorapatite samples are of nano size and homogenous in composition. • The Ag+-doped fluorapatite samples showed antibacterial effect against Kllebsiela pneumoniae, Staphylococcus aureus and Micrococcus luteus. • AFM studies showed that silver-doped sample causes considerable morphological changes of tested bacterial cells. - Abstract: Silver doped fluorapatite nanopowders were synthesised by neutralization method, which consists of dissolving Ag2O in solution of HF and H3PO4 and addition to suspension of Ca(OH)2. The powder XRD, SEM and FTIR studies indicated the formation of a fluorapatite nanomaterials with average length of the particles is about 80 nm and a width of about 15 nm. The FTIR studies show that carbonate content in samples is very small and carbonte ions substitute both phosphate and hydroxyl groups in the crystal structure of samples, forming AB-type fluorapatite. Antibacterial studies have demonstrated that all Ag+-doped fluorapatite samples exhibit bactericidal effect against pathogens: Staphylococcus aureus, Micrococcus luteus and Kllebsiela pneumoniae. Antibacterial activity increased with the increase of Ag+ in the samples. The atomic force microscopy studies revealed extensive damage to the bacterial cell envelops in the presence of Ag+-doped fluorapatite particles which may lead to their death. The synthesized Ag+-doped fluorapatite nanomaterials are promising as antibacterial biomaterials in orthopedics and dentistry

  10. CrN-Ag nanocomposite coatings: Control of lubricant transport by diffusion barriers

    Energy Technology Data Exchange (ETDEWEB)

    Papi, P.A. [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); 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); Gall, D., E-mail: galld@rpi.edu [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

    2012-12-01

    1-{mu}m-thick self-lubricating CrN-Ag composite coatings containing 16 at.% Ag were deposited on Si substrates by reactive co-sputtering at T{sub s} = 400 Degree-Sign C, and were covered with CrN cap layers with a columnar microstructure and a thickness d = 0-1000 nm. Vacuum annealing at T{sub a} = 500 and 600 Degree-Sign C for 1 h causes Ag transport to the sample surface and the formation of Ag surface grains. Quantitative scanning electron microscopy and energy dispersive spectroscopy analyses show that increasing d from 0 to 10 to 100 nm for T{sub a} = 500 Degree-Sign C leads to a decrease in the areal density of Ag surface grains from 0.86 to 0.45 to 0.04 {mu}m{sup -2}, while their lateral size remains constant at 360 {+-} 60 nm. However, increasing T{sub a} to 600 Degree-Sign C causes a doubling of the Ag grain size, and a 4-30 times larger overall Ag transport. These results are explained by kinetic barriers for Ag diffusion through the porous cap layer with a porosity that decreases with increasing d, resulting in an effective activation barrier for Ag transport that increases from 0.78 eV in the absence of a cap layer to 0.89 eV for d = 10 nm and 1.07 eV for d = 30 nm. Auger electron spectroscopy depth profile analyses of annealed layers reveal no detectable Ag within the CrN cap layer and a uniform depletion of the Ag reservoir throughout the composite coating thickness, indicating unhindered Ag transport within the composite. The overall results show that a CrN diffusion barrier cap layer is an effective approach to control Ag lubricant transport to the surface of CrN-Ag composite coatings. - Highlights: Black-Right-Pointing-Pointer CrN-Ag composite coatings are capped with CrN diffusion barriers. Black-Right-Pointing-Pointer Ag diffuses to the surface during annealing at 500 or 600 Degree-Sign C. Black-Right-Pointing-Pointer The Ag transport is controlled by the cap thickness d = 0-1000 nm. Black-Right-Pointing-Pointer The activation energy for Ag

  11. NMR investigation of Ag nanoparticles

    Science.gov (United States)

    Son, Kwanghyo; Jang, Zeehoon

    2013-01-01

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

  12. 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.

  13. 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.)

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

    Science.gov (United States)

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

    2016-05-24

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

  15. The Structure and Emission Properties of SiO2 Nanometer Film Containing Ag

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Colloidal silver particles are formed on float glass by heat treatment with coated silica film containing Ag by sol-gel process.The Sn2+on surface of float glass influences the formation of colloidal Ag particles.The microstructure of the film and the granularity of silver particles were studied by TEM and HEED.The emission property of the samples was measured.The results show that aggregation of metal particles degrades emission intensity,and that content of Ag,withdrawing speed and heat treatment temperature of samples has a greater effect on photoluminescence.

  16. No evidence of association between 118A>G OPRM1 polymorphism and heroin dependence in a large Bulgarian case-control sample.

    Science.gov (United States)

    Nikolov, Momchil A; Beltcheva, Olga; Galabova, Antoaneta; Ljubenova, Anna; Jankova, Elena; Gergov, Galin; Russev, Atanas A; Lynskey, Michael T; Nelson, Elliot C; Nesheva, Eleonora; Krasteva, Dorita; Lazarov, Philip; Mitev, Vanio I; Kremensky, Ivo M; Kaneva, Radka P; Todorov, Alexandre A

    2011-08-01

    The μ-opioid receptor is the primary site of action of most opioids. The 118A>G (rs1799971) polymorphism in exon 1 of the μ-opioid receptor gene (OPRM1) leads to an Asn40Asp amino acid change that affects a putative N-glycosylation site. It has been widely investigated for association with alcohol and drug dependence and pain sensitivity, with mixed results. The aim of the current study was to examine whether this polymorphism was associated with heroin dependence in a large Bulgarian cohort of 1842 active users and 1451 population controls. SNP genotyping was done using Real-Time PCR TaqMan technology. Association analyses were conducted, separately for Roma and non-Roma participants. Our results suggest that there is no direct effect of 118A>G genotype on the risk for heroin dependence among active heroin users.

  17. In silico sampling reveals the effect of clustering and shows that the log-normal rank abundance curve is an artefact

    OpenAIRE

    Neuteboom, J.H.; Struik, P. C.

    2005-01-01

    The impact of clustering on rank abundance, species-individual (S-N)and species-area curves was investigated using a computer programme for in silico sampling. In a rank abundance curve the abundances of species are plotted on log-scale against species sequence. In an S-N curve the number of species (S) is plotted against the log of the total number of individuals (N) in the sample, in a species-area curve S is plotted against log-area. The results from in silico sampling confirm the general ...

  18. Morphology-controlled synthesis of Ag3PO4 nano/microcrystals and their antibacterial properties

    International Nuclear Information System (INIS)

    Graphical abstract: The Ag3PO4 with rhombic dodecahedral, spherical and small size particles were controllable fabricated just by changing the types of the solvent. The materials possess good antibacterial properties toward different kinds of bacteria. - Highlights: • The Ag3PO4 with three morphologies were controllable fabricated. • The Ag3PO4 as-prepared possess obvious antibacterial properties in the dark. • The antibacterial ability of Ag3PO4 could be greatly improved under the visible light irradiation. - Abstract: We reported the controllable fabrication of Ag3PO4 nano/microcrystals through a simple solution-based precipitation reaction. The samples were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy and infrared spectroscopy. The results indicated that the Ag3PO4 crystals with three different morphology, including the rhombic dodecahedron of 500 nm, the sphere of 100 nm and the particles with small-size of 20 nm, could be obtained in the solvents of water, ethylene glycol (EG) and dimethyl sulfoxide (DMSO). The antibacterial assay showed that all samples possess obvious antibacterial properties. In addition, the Ag3PO4 with small size of 20 nm showed better activity due to their high specific surface areas. Notably, we have found that the antibacterial ability of Ag3PO4 could be greatly improved under the visible light irradiation, which are superior to that in the dark and commercial streptomycin

  19. Sample preparation strategies for food and biological samples prior to nanoparticle detection and imaging

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Löschner, Katrin

    2014-01-01

    microscopy (TEM) proved to be necessary for trouble shooting of results obtained from AFFF-LS-ICP-MS. Aqueous and enzymatic extraction strategies were tested for thorough sample preparation aiming at degrading the sample matrix and to liberate the AgNPs from chicken meat into liquid suspension. The resulting...... for the meat sample extracts and the corresponding neat AgNP suspension, and rendered sizing by way of calibration with AgNPs as sizing standards inaccurate. In order to gain further insight into the sizes of the separated AgNPs, or their possible dissolved state, fractions of the AFFF eluate were collected......-ICP-MS analysis of their content of gold nanoparticles (AuNPs) was tested and compared with enzymatic sample preparation [3]. The results showed that the same results, with respect to the obtained number-based size distribution for AuNPs, were obtained for the two preparation methods. In contrast, the alkaline...

  20. Show Time

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正> Story: Show Time!The whole class presents the story"Under the Sea".Everyone is so excited and happy.Both Leo and Kathy show their parentsthe characters of the play."Who’s he?"asks Kathy’s mom."He’s the prince."Kathy replies."Who’s she?"asks Leo’s dad."She’s the queen."Leo replieswith a smile.

  1. Snobbish Show

    Institute of Scientific and Technical Information of China (English)

    YIN PUMIN

    2010-01-01

    @@ The State Administration of Radio,Film and Television (SARFT),China's media watchdog,issued a new set of mles on June 9 that strictly regulate TV match-making shows,which have been sweeping the country's primetime programming. "Improper social and love values such as money worship should not be presented in these shows.Humiliation,verbal attacks and sex-implied vulgar content are not allowed" the new roles said.

  2. Blood Staions’ Study on the Correlation between HBsAg detection via ELISA and the Reactive Samples with PCR%血站HBsAg反应性样本的ELISA与PCR法检测结果的相关性

    Institute of Scientific and Technical Information of China (English)

    冯娟

    2016-01-01

    Objective To explore the agreement between the testing results of reactive samples by ELISA for HBsAg and HBV DNA by PCR,so as that a more accurate testing may be provided for the donors.Methods PCR was apply to the reactive samples from volunteer donors who had been tested by ELISA for HBsAg to make a comparison between the results. Results By employing two ELISA reagents,698 samples are tested to be reacted positively in the total of122,675. Among the698 samples, there are382 have been equally detected positive by the two ELISA reagents.203 cases were found PCR positive, account for29.08%.179 cases are PCR negative, account for25.64%. Among the204 positive samples tested by one ELISA reagent,8 cases are found PCR positive, account for1.15%;196 negative cases existed, account for28.08%. By employing two ELISA reagents,5 samples were within the gray area. None of them were positive for PCR, account for0%; while5 negative were observed, account for0.72%; by employing one single ELISA reagent,107 cases were within the gray area and5 cases were PCR positive, comprise0.72%;102 are negative, account for14.61 %.Conclusion In the HBsAg blood screening, different ELISIA reagents showed different degrees of sensitivity and specificity. If double reagents are applied, the positive reaction results are more likely to be consistent with the results from HBV DNA. A few cases within gray area are also identical with them, but the development of HBV DNA should be closely observed and followed-up.%目的:探讨无偿献血者ELISA法检测HBsAg反应性样本与PCR检测HBV DNA结果的符合程度,为献血者提供更为准确的检测结果;并探讨新模式下,两种检测方法的结果报告及血源的召回制度。方法对无偿献血者ELISA法检测HBsAg反应性样本,采用PCR检测,并进行结果比较。结果122657份献血者样本中,2种ELISA试剂共检测出反应性样本698例,其中2种ELISA试剂检测均为阳性样本382

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

    Directory of Open Access Journals (Sweden)

    Petr Suchomel

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

  4. In silico sampling reveals the effect of clustering and shows that the log-normal rank abundance curve is an artefact

    NARCIS (Netherlands)

    Neuteboom, J.H.; Struik, P.C.

    2005-01-01

    The impact of clustering on rank abundance, species-individual (S-N)and species-area curves was investigated using a computer programme for in silico sampling. In a rank abundance curve the abundances of species are plotted on log-scale against species sequence. In an S-N curve the number of species

  5. Synthesis, characterization and multifunctional properties of plasmonic Ag-TiO2 nanocomposites.

    Science.gov (United States)

    Prakash, Jai; Kumar, Promod; Harris, R A; Swart, Chantel; Neethling, J H; van Vuuren, A Janse; Swart, H C

    2016-09-01

    We report on the synthesis of multifunctional Ag-TiO2 nanocomposites and their optical, physio-chemical, surface enhanced Raman scattering (SERS) and antibacterial properties. A series of Ag-TiO2 nanocomposites were synthesized by sol-gel technique and characterized by x-ray diffraction, scanning and transmission electron microscopy, energy-dispersed x-ray analysis, photoluminescence, UV-vis, x-ray photoelectron and Raman spectroscopy and Brunauer-Emmett-Teller method. The Ag nanoparticles (NPs) (7-20 nm) were found to be uniformly distributed around and strongly attached to TiO2 NPs. The novel optical responses of the nanocomposites are due to the strong electric field from the localized surface plasmon (LSP) excitation of the Ag NPs and decreased recombination of photo-induced electrons and holes at Ag-TiO2 interface providing potential materials for photocatalysis. The nanocomposites show enhancement in the SERS signals of methyl orange (MO) molecules with increasing Ag content attributed to the long-range electromagnetic enhancement from the excited LSP of the Ag NPs. To further understand the SERS activity, molecular mechanics and molecular dynamics simulations were used to study the geometries and SERS enhancement of MO adsorbed onto Ag-TiO2 respectively. Simulation results indicate that number of ligands (MO) that adsorb onto the Ag NPs as well as binding energy per ligand increases with increasing NP density and molecule-to-surface orientation is mainly flat resulting in strong bond strength between MO and Ag NP surface and enhanced SERS signals. The antimicrobial activity of the Ag-TiO2 nanocomposites was tested against the bacterium Staphylococcus aureus and enhanced antibacterial effect was observed with increasing Ag content explained by contact killing action mechanism. These results foresee promising applications of the plasmonic metal-semiconductor based nano-biocomposites for both chemical and biological samples. PMID:27456278

  6. Synthesis, characterization and multifunctional properties of plasmonic Ag-TiO2 nanocomposites

    Science.gov (United States)

    Prakash, Jai; Kumar, Promod; Harris, R. A.; Swart, Chantel; Neethling, J. H.; Janse van Vuuren, A.; Swart, H. C.

    2016-09-01

    We report on the synthesis of multifunctional Ag-TiO2 nanocomposites and their optical, physio-chemical, surface enhanced Raman scattering (SERS) and antibacterial properties. A series of Ag-TiO2 nanocomposites were synthesized by sol-gel technique and characterized by x-ray diffraction, scanning and transmission electron microscopy, energy-dispersed x-ray analysis, photoluminescence, UV-vis, x-ray photoelectron and Raman spectroscopy and Brunauer-Emmett-Teller method. The Ag nanoparticles (NPs) (7-20 nm) were found to be uniformly distributed around and strongly attached to TiO2 NPs. The novel optical responses of the nanocomposites are due to the strong electric field from the localized surface plasmon (LSP) excitation of the Ag NPs and decreased recombination of photo-induced electrons and holes at Ag-TiO2 interface providing potential materials for photocatalysis. The nanocomposites show enhancement in the SERS signals of methyl orange (MO) molecules with increasing Ag content attributed to the long-range electromagnetic enhancement from the excited LSP of the Ag NPs. To further understand the SERS activity, molecular mechanics and molecular dynamics simulations were used to study the geometries and SERS enhancement of MO adsorbed onto Ag-TiO2 respectively. Simulation results indicate that number of ligands (MO) that adsorb onto the Ag NPs as well as binding energy per ligand increases with increasing NP density and molecule-to-surface orientation is mainly flat resulting in strong bond strength between MO and Ag NP surface and enhanced SERS signals. The antimicrobial activity of the Ag-TiO2 nanocomposites was tested against the bacterium Staphylococcus aureus and enhanced antibacterial effect was observed with increasing Ag content explained by contact killing action mechanism. These results foresee promising applications of the plasmonic metal-semiconductor based nano-biocomposites for both chemical and biological samples.

  7. EROBATIC SHOW

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    Visitors look at plane models of the Commercial Aircraft Corp. of China, developer of the count,s first homegrown large passenger jet C919, during the Singapore Airshow on February 16. The biennial event is the largest airshow in Asia and one of the most important aviation and defense shows worldwide. A number of Chinese companies took part in the event during which Okay Airways, the first privately owned aidine in China, signed a deal to acquire 12 Boeing 737 jets.

  8. Functional behavior of the anomalous magnetic relaxation observed in melt-textured YBa2Cu3O7-δ samples showing the paramagnetic Meissner effect

    Science.gov (United States)

    Dias, F. T.; Vieira, V. N.; Garcia, E. L.; Wolff-Fabris, F.; Kampert, E.; Gouvêa, C. P.; Schaf, J.; Obradors, X.; Puig, T.; Roa, J. J.

    2016-10-01

    We have studied the functional behavior of the field-cooled (FC) magnetic relaxation observed in melt-textured YBa2Cu3O7-δ (Y123) samples with 30 wt% of Y2Ba1Cu1O5 (Y211) phase, in order to investigate anomalous paramagnetic moments observed during the experiments. FC magnetic relaxation experiments were performed under controlled conditions, such as cooling rate and temperature. Magnetic fields up to 5T were applied parallel to the ab plane and along the c-axis. Our results are associated with the paramagnetic Meissner effect (PME), characterized by positive moments during FC experiments, and related to the magnetic flux compression into the samples. After different attempts our experimental data could be adequately fitted by an exponential decay function with different relaxation times. We discuss our results suggesting the existence of different and preferential flux dynamics governing the anomalous FC paramagnetic relaxation in different time intervals. This work is one of the first attempts to interpret this controversial effect in a simple analysis of the pinning mechanisms and flux dynamics acting during the time evolution of the magnetic moment. However, the results may be useful to develop models to explain this interesting and still misunderstood feature of the paramagnetic Meissner effect.

  9. Highly luminescent material based on Alq3:Ag nanoparticles.

    Science.gov (United States)

    Salah, Numan; Habib, Sami S; Khan, Zishan H

    2013-09-01

    Tris (8-hydroxyquinoline) aluminum (Alq3) is an organic semiconductor molecule, widely used as an electron transport layer, light emitting layer in organic light-emitting diodes and a host for fluorescent and phosphorescent dyes. In this work thin films of pure and silver (Ag), cupper (Cu), terbium (Tb) doped Alq3 nanoparticles were synthesized using the physical vapor condensation method. They were fabricated on glass substrates and characterized by X-ray diffraction, scanning electron microscope (SEM), energy dispersive spectroscopy, atomic force microscope (AFM), UV-visible absorption spectra and studied for their photoluminescence (PL) properties. SEM and AFM results show spherical nanoparticles with size around 70-80 nm. These nanoparticles have almost equal sizes and a homogeneous size distribution. The maximum absorption of Alq3 nanoparticles is observed at 300 nm, while the surface plasmon resonant band of Ag doped sample appears at 450 nm. The PL emission spectra of Tb, Cu and Ag doped Alq3 nanoparticles show a single broad band at around 515 nm, which is similar to that of the pure one, but with enhanced PL intensity. The sample doped with Ag at a concentration ratio of Alq3:Ag = 1:0.8 is found to have the highest PL intensity, which is around 2 times stronger than that of the pure one. This enhancement could be attributed to the surface plasmon resonance of Ag ions that might have increased the absorption and then the quantum yield. These remarkable result suggest that Alq3 nanoparticles incorporated with Ag ions might be quite useful for future nano-optoelectronic devices. PMID:23653126

  10. Hydroxyapatite supported Ag3PO4 nanoparticles with higher visible light photocatalytic activity

    Science.gov (United States)

    Hong, Xiaoting; Wu, Xiaohui; Zhang, Qiuyun; Xiao, Mingfeng; Yang, Gelin; Qiu, Meirong; Han, Guocheng

    2012-03-01

    Hydroxyapatite supported Ag3PO4 nanocomposites have been synthesized by a wet impregnation process. UV-vis absorption spectra show a red shift of the absorption edges for the composite systems compared to pure hydroxyapatite support. The surface structure and morphology of the nanocomposites were characterized by Brunauer-Emmett-Teller (BET) apparatus, X-ray diffraction (XRD), transmission electron microscopy (TEM). The results suggest that Ag3PO4 nanoparticles (6-17 nm in diameter) are well dispersed on the hydroxyapatite support and Ag3PO4 nanoparticles density is larger for the higher Ag+ loading sample. The as-prepared nanocomposite photocatalysts showed a pronounced photocatalytic activity upon decomposition of methylene blue dye in aqueous solution under both visible light (wavelength > 400 nm) and UV-vis light irradiation. A synergic mechanism of inherent photocatalytic capability of Ag3PO4 and the accelerated electron/hole separation resulting from the photoinduced electrons captured by the slow-released Ag+ at the interface of Ag3PO4 and hydroxyapatite is proposed for the nanocomposites on the enhancement of photocatalytic performance in comparison to that of pure Ag3PO4 nanoparticles. The support of hydroxyapatite may also act as an absorbent which favors the mass transfer in heterogeneous photocatalysis reaction.

  11. Reduction of conductivity and ferromagnetism induced by Ag doping in ZnO:Co

    Energy Technology Data Exchange (ETDEWEB)

    Bieber, H.; Colis, S.; Schmerber, G.; Pierron-Bohnes, V. [Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504 UDS-CNRS (UDS-ECPM), 23 Rue du Loess, BP 43, F-67034 Strasbourg Cedex 2 (France); Boukhvalov, D.W., E-mail: danil@kias.re.kr [School of Computational Sciences, Korea Institute for Advanced Study (KIAS), Hoegiro 87, Dongdaemun-Gu, Seoul 130-722 (Korea, Republic of); Kurmaev, E.Z.; Finkelstein, L.D. [Institute of Metal Physics, Russian Academy of Sciences—Ural Division, 620990 Yekaterinburg (Russian Federation); Bazylewski, P.; Moewes, A.; Chang, G.S. [Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, SK S7N 5E2 (Canada); Dinia, A., E-mail: aziz.dinia@ipcms.u-strasbg.fr [Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504 UDS-CNRS (UDS-ECPM), 23 Rue du Loess, BP 43, F-67034 Strasbourg Cedex 2 (France)

    2013-10-31

    Cobalt and silver co-doping has been undertaken in ZnO thin films grown by pulsed laser deposition in order to investigate the ferromagnetic properties in ZnO-based diluted magnetic materials and to understand the eventual relation between ferromagnetism and charge carriers. Hall transport measurements reveal that Ag doping up to 5% leads to a progressive compensation of the native n-type carriers. The magnetization curves show ferromagnetic contributions for all samples at both 5 K and room temperature, decreasing with increasing the Ag concentration. First principles modeling of the possible configurations of Co–Ag defects suggests the formation of nano-clusters around interstitial Co impurity as the origin of the ferromagnetism. The Ag co-doping results in a decrease of the total spin of these clusters and of the Curie temperature. - Highlights: • We fabricate ZnO:Co films co-doped by Ag. • Reduction of the number of charge carriers in co-doped samples is observed. • Decrease of magnetic moment per Co in Ag-rich samples is observed. • Theoretical calculations support suppression of ferromagnetism in Ag-doped ZnO:Co.

  12. 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)

  13. Sodium cholate-templated blue light-emitting Ag subnanoclusters: in vivo toxicity and imaging in zebrafish embryos.

    Science.gov (United States)

    Chandirasekar, Shanmugam; Chandrasekaran, Chandramouli; Muthukumarasamyvel, Thangavel; Sudhandiran, Ganapasam; Rajendiran, Nagappan

    2015-01-28

    We report a novel green chemical approach for the synthesis of blue light-emitting and water-soluble Ag subnanoclusters, using sodium cholate (NaC) as a template at a concentration higher than the critical micelle concentration (CMC) at room temperature. However, under photochemical irradiation, small anisotropic and spherically shaped Ag nanoparticles (3-11 nm) were obtained upon changing the concentration of NaC from below to above the CMC. The matrix-assisted laser desorption ionization time-of-flight and electrospray ionization mass spectra showed that the cluster sample was composed of Ag4 and Ag6. The optical properties of the clusters were studied by UV-visible and luminescence spectroscopy. The lifetime of the synthesized fluorescent Ag nanoclusters (AgNCs) was measured using a time-correlated single-photon counting technique. High-resolution transmission electron microscopy was used to assess the size of clusters and nanoparticles. A protocol for transferring nanoclusters to organic solvents is also described. Toxicity and bioimaging studies of NaC templated AgNCs were conducted using developmental stage zebrafish embryos. From the survival and hatching experiment, no significant toxic effect was observed at AgNC concentrations of up to 200 μL/mL, and the NC-stained embryos exhibited blue fluorescence with high intensity for a long period of time, which shows that AgNCs are more stable in living system.

  14. Ag nanoparticle/ZnO nanorods nanocomposites derived by a seed-mediated method and their photocatalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Yin Xingtian [Electronic Materials Research Laboratory, School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an 710049, Shaanxi (China); Que Wenxiu, E-mail: wxque@mail.xjtu.edu.cn [Electronic Materials Research Laboratory, School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an 710049, Shaanxi (China); Fei Duan; Shen Fengyu; Guo Qiushi [Electronic Materials Research Laboratory, School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an 710049, Shaanxi (China)

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer Hedgehog-like Ag nanoparticle/ZnO nanorods (Ag NP/ZnO NRs) core/shell nanocomposites were prepared by a seed-mediated method. Black-Right-Pointing-Pointer ZnO NRs can grow directly on the surface of the Ag NPs without any other ancillary seed-assisted process. Black-Right-Pointing-Pointer The volume content ratio of the Ag NPs colloids and the ZnO precursory solution is crucial for the morphology of the resulted samples. Black-Right-Pointing-Pointer Both the heterostructure and the smaller size of resulted crystals contribute to the enhanced photocatalytic performance. - Abstract: Ag nanoparticle/ZnO nanorods (Ag NP/ZnO NRs) nanocomposites with a core/shell structure were prepared by a seed-mediated method, which contains a polyol synthesis of Ag NPs and an overgrowth process of ZnO NRs on the surface of Ag NPs. Compared with the previously reported Ag/ZnO nanocomposites which were mostly constructed by a ZnO core and a Ag shell, the nanocomposites reported in this article showed a novel structure that contained a Ag NP core and ZnO NRs shell, resulting a hedgehog-like morphology. Electron microscope images reveal that the volume content ratio of Ag NPs colloids and the ZnO precursory solution is crucial for the morphology of the resulted samples and a well-constructed Ag NP/ZnO NRs core/shell nanocomposite can be easily obtained when their volume content ratio is set at a proper value. X-ray diffraction analysis shows a good crystalline property of both Ag NPs and ZnO NRs. The relationship between the growing temperature and the morphology of the resulted samples was investigated and a possible growing mechanism of the Ag NP/ZnO NRs nanocomposites was also proposed and discussed. Furthermore, photocatalytic activities of the resulting samples with different morphologies were also studied.

  15. Nonlinear optical properties and optical limiting measurements of graphene oxide - Ag@TiO2 compounds

    Science.gov (United States)

    Ebrahimi, M.; Zakery, A.; Karimipour, M.; Molaei, M.

    2016-07-01

    In this work Graphene Oxide (GO), Ag@TiO2 core-shells and GO-Ag@TiO2 compounds were prepared and experimentally verified. Using a low power laser diode with 532 nm wavelength, the magnitude and the sign of the nonlinear refractive index and nonlinear absorption were determined by the Z-scan technique. It was observed that the nonlinear absorption of GO-Ag@TiO2 mixture was higher than pure GO. The optical limiting effect of these samples was also investigated using the 2nd harmonics of a pulsed Nd-YAG laser at 532 nm. Our results showed that the sole Ag@TiO2 didn't show any appreciable optical limiting effect, however after just mixing with graphene oxide the threshold of optical limiting was increased and the compound showed an enhancement of optical limiting behavior compared to GO itself. The presented results are discussed and compared with other literature reports.

  16. Fuzzy Cosets and Quotient Fuzzy AG-subgroups

    OpenAIRE

    Amanullah,; Ahmad, Imtiaz; Shah, Muhammad

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Riemawati A. Lesmana

    2015-10-01

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

  18. The optical and mechanical properties of PVA-Ag nanocomposite films

    International Nuclear Information System (INIS)

    Highlights: • We prepared PVA -Ag composite films which used in different filed of applications. • The XRD results showed Ag nanoparticles entering the polymer PVA matrix. • Optical band gap as a result of doping has been found to be reduced significantly. • Young's modulus increases while the strain decreases due to increasing Ag content. -- Abstract: Poly (vinyl alcohol) (PVA) loaded silver (Ag) nanoparticles were successfully prepared by chemical reduction methods. The synthesized nanoparticles are characterized using UV–visible spectrophotometer, X-ray diffractometer (XRD) and Transmission electron microscope (TEM). The contents of the inorganic phase in the nanocomposites were determined by using atomic absorption spectroscopy (AA) for silver, and were found to be 0.2, 0.4, 0.8 and 1.5 wt.%. Optical absorption studies in the wavelength range 190–900 nm showed additional peak at 420 nm for differently doped films, in addition to the peak at 200 nm for undoped PVA film. There is observable change in the absorbed intensity at 420 nm with filling levels. This is due to the link between the Ag metal ion and the polymer OH- groups. The indirect energy gaps were calculated. It was found that Young’s modulus and the strength at the break increase, while the energy gaps and the strain decrease as the concentration of Ag content is increased. The XRD results showed that the Ag nanoparticles entering the polymer PVA matrix and the crystallinity was strongly influenced by the amount of Ag nanoparticles. The electron diffraction image for the highest concentration sample shows the crystalline nature of the silver metal nanoparticles. TEM of the nanocomposite films revealed the presence of Ag particles with average diameter of 12 nm

  19. Sensitive electrochemical sensor of tryptophan based on Ag-C core-shell nanocomposite modified glassy carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mao Shuxian [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Li Weifeng, E-mail: liweifeng@suda.edu.cn [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Long Yumei, E-mail: yumeilong@suda.edu.cn [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Tu Yifeng; Deng, Anping [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China)

    2012-08-13

    Graphical abstract: Ag-C and Colloidal carbon sphere modified glassy carbon electrodes were prepared. It was clear that the Ag-C/GCE exhibited enhanced electrocatalytic activity towards Trp, which could result from the synergistic effect between Ag core and carbon shell. The Ag-C/GCE showed excellent analytical properties in the determination of Trp. Highlights: Black-Right-Pointing-Pointer The electrochemical behavior of Ag-C core-shell nanocomposite was firstly proposed. Black-Right-Pointing-Pointer Ag-C/GC electrode exhibited favorable electrocatalytic properties towards Trp. Black-Right-Pointing-Pointer The good electrocatalysis was due to the synergistic effect of Ag-core and C-shell. Black-Right-Pointing-Pointer The Ag-C/GC electrode displayed excellent analytical properties in determining Trp. - Abstract: We here reported a simple electrochemical method for the detection of tryptophan (Trp) based on the Ag-C modified glassy carbon (Ag-C/GC) electrode. The Ag-C core-shell structured nanoparticles were synthesized using one-pot hydrothermal method and characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), and Fourier transform-infrared spectroscopy (FTIR). The electrochemical behaviors of Trp on Ag-C/GC electrode were investigated and exhibited a direct electrochemical process. The favorable electrochemical properties of Ag-C/GC electrode were attributed to the synergistic effect of the Ag core and carbon shell. The carbon shell cannot only protect Ag core but also contribute to the enhanced substrate accessibility and Trp-substrate interactions, while nano-Ag core can display good electrocatalytic activity to Trp at the same time. Under the optimum experimental conditions the oxidation peak current was linearly dependent on the Trp concentration in the range of 1.0 Multiplication-Sign 10{sup -7} to 1.0 Multiplication-Sign 10{sup -4} M with a detection limit of 4.0 Multiplication-Sign 10{sup -8} M (S/N = 3). In addition

  20. Fabrication of AgX-loaded Ag2CO3 (X = Cl, I) composites and their efficient visible-light-driven photocatalytic activity

    International Nuclear Information System (INIS)

    Highlights: • The novel AgX/Ag2CO3 composites have been synthesized by ion exchange reaction. • AgX/Ag2CO3 exhibit higher photoactivity and stability than that of Ag2CO3. • The band structure of AgX/Ag2CO3 is beneficial to improve the photoactivity. - Abstract: The novel visible-light-driven AgX/Ag2CO3 (X = Cl, I) hybrid materials were synthesized by ion exchange reaction. The physical and chemical properties of the catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), diffuse-reflection spectra (DRS) and photocurrent techniques. The as-prepared AgX/Ag2CO3 (X = Cl, I) composites showed higher photocatalytic activity than that of the pure Ag2CO3 photocatalyst under visible light irradiation (λ ⩾ 400 nm) in the process of methylene blue (MB) degradation. The optimal mass percentage of AgCl and AgI in the AgX/Ag2CO3 (X = Cl, I) composite was 20.54 wt% and 40 wt%, respectively. The enhancement of photocatalytic activity was attributed to the suitable band potential between AgX and Ag2CO3, which was beneficial to increase the separation efficiency of electrons and holes. Besides, the photocatalytic mechanism of AgX/Ag2CO3 (X = Cl, I) composites was also proposed

  1. 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.

  2. 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...

  3. Low-energy neutron irradiation on Bi-based (2223 Ag superconductors

    Directory of Open Access Journals (Sweden)

    H Najafpour

    2009-08-01

    Full Text Available  Bi-based and Ag-doped superconductors were irradiated by neutrons. Experimental result showed that XRD patern-intensity of irradiated Bi-based sample was decreased and The Tc of these samples were decreased by 7-10 K. The neutron irradiated sample was also found to decrease by 50% the normal state resistivity of samples. Therefore, neutron irradiation is a useful method to improve the superconductivity behavior of Bi-based materials.

  4. Hydroxyapatite supported Ag{sub 3}PO{sub 4} nanoparticles with higher visible light photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Hong Xiaoting, E-mail: hanren.xiaoting@gmail.com [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Wu Xiaohui; Zhang Qiuyun; Xiao Mingfeng; Yang Gelin; Qiu Meirong; Han Guocheng [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China)

    2012-03-01

    Hydroxyapatite supported Ag{sub 3}PO{sub 4} nanocomposites have been synthesized by a wet impregnation process. UV-vis absorption spectra show a red shift of the absorption edges for the composite systems compared to pure hydroxyapatite support. The surface structure and morphology of the nanocomposites were characterized by Brunauer-Emmett-Teller (BET) apparatus, X-ray diffraction (XRD), transmission electron microscopy (TEM). The results suggest that Ag{sub 3}PO{sub 4} nanoparticles (6-17 nm in diameter) are well dispersed on the hydroxyapatite support and Ag{sub 3}PO{sub 4} nanoparticles density is larger for the higher Ag{sup +} loading sample. The as-prepared nanocomposite photocatalysts showed a pronounced photocatalytic activity upon decomposition of methylene blue dye in aqueous solution under both visible light (wavelength > 400 nm) and UV-vis light irradiation. A synergic mechanism of inherent photocatalytic capability of Ag{sub 3}PO{sub 4} and the accelerated electron/hole separation resulting from the photoinduced electrons captured by the slow-released Ag{sup +} at the interface of Ag{sub 3}PO{sub 4} and hydroxyapatite is proposed for the nanocomposites on the enhancement of photocatalytic performance in comparison to that of pure Ag{sub 3}PO{sub 4} nanoparticles. The support of hydroxyapatite may also act as an absorbent which favors the mass transfer in heterogeneous photocatalysis reaction.

  5. Synthesis of Diverse Ag2O Crystals and Their Facet-Dependent Photocatalytic Activity Examination.

    Science.gov (United States)

    Chen, Ying-Jui; Chiang, Yun-Wei; Huang, Michael H

    2016-08-01

    Sub- to micrometer-sized Ag2O cubes, great rhombicuboctahedra, cuboctahedra, corner-truncated octahedra, octahedra, and rhombic dodecahedra have been synthesized at room temperature using simple molar ratios of NH4NO3, NaOH, and AgNO3 solutions with a short reaction time. In addition, tuning the concentration of NH3 in the solution can provide more particle morphologies including edge- and corner-truncated cubes, small rhombicuboctahedra, and edge-truncated octahedra to enrich Ag2O shape diversity. X-ray photoelectron spectroscopy (XPS) spectra indicate surface composition of various crystals as pure Ag2O. Diffuse reflectance spectra have been used to determine the band gap of Ag2O cubes. Ag2O cubes, octahedra, and rhombic dodecahedra having the same total particle surface area were used for facet-dependent photocatalytic activity comparison in the degradation of methyl orange. Cubes are comparably highly active for this reaction, while octahedra and rhombic dodecahedra give moderate and low catalytic activities, respectively. Electron paramagnetic resonance (EPR) measurements confirm this reactivity order. Although all Ag2O samples show significant etching during photocatalysis, metallic silver is not produced. PMID:27411371

  6. Synthesis and characterization of Fe 3 O 4 @C@Ag nanocomposites and their antibacterial performance

    Science.gov (United States)

    Xia, Haiqing; Cui, Bin; Zhou, Junhong; Zhang, Lulu; Zhang, Ji; Guo, Xiaohui; Guo, Huilin

    2011-09-01

    We synthesized Fe 3O 4@C@Ag nanocomposites through a combination of solvothermal, hydrothermal, and chemical redox reactions. Characterization of the resulting samples by X-ray diffraction, Fourier-transform infrared spectroscopy, field-emission scanning and transmission electron microscopy, and magnetic measurement is reported. Compared to Fe 3O 4@Ag nanocomposites, the Fe 3O 4@C@Ag nanocomposites showed enhanced antibacterial activity. The Fe 3O 4@C@Ag nanocomposites were able to almost entirely prevent growth of Escherichia coli when the concentration of Ag nanoparticles was 10 μg/mL. Antibacterial activity of the Fe 3O 4@C@Ag nanocomposites was maintained for more than 40 h at 37 °C. The intermediate carbon layer not only protects magnetic core, but also improves the dispersion and antibacterial activity of the silver nanoparticles. The magnetic core can be used to control the specific location of the antibacterial agent (via external magnetic field) and to recycle the residual silver nanoparticles. The Fe 3O 4@C@Ag nanocomposites will have potential uses in many fields as catalysts, absorbents, and bifunctional magnetic-optical materials.

  7. Optical properties of silver sulphide thin films formed on evaporated Ag by a simple sulphurization method

    Energy Technology Data Exchange (ETDEWEB)

    Barrera-Calva, E., E-mail: ebc@xanum.uam.m [Departamento de Ingenieria de Procesos e hidraulica, Universidad Autonoma Metropolitana - Iztapalapa, Av. Purisima Esq. Michoacan, Col. Vicentina, Mexico, D.F., 09340 (Mexico); Ortega-Lopez, M.; Avila-Garcia, A.; Matsumoto-Kwabara, Y. [Departamento de Ingenieria Electrica, Centro de Investigacion y de Estudios Avanzados del IPN, Mexico DF 07360 (Mexico)

    2010-01-31

    Silver sulphide (Ag{sub 2}S) thin films were grown on the surface of silver films (Ag) deposited on glass substrate by using a simple chemical sulphurization method. According to X-ray diffraction analysis, the Ag{sub 2}S thin films display low intensity peaks at 34.48{sup o}, 36.56{sup o}, and 44.28{sup o}, corresponding to diffraction from (100), (112) and (103) planes of the acanthite phase (monoclinic). A model of the type Ag{sub 2}S/Ag/glass was deduced from spectroscopic ellipsometric measurements. Also, the optical constants (n, k) of the system were determined. Furthermore, the optical properties as solar selective absorber for collector applications were assessed. The optical reflectance of the Ag{sub 2}S/Ag thin film systems exhibits the expected behavior for an ideal selective absorber, showing a low reflectance in the wavelength range below 2 {mu}m and a high reflectance for wavelengths higher than that value. An absorptance about 70% and an emittance about 3% or less were calculated for several samples.

  8. Microstructures and magnetic properties of [SiO2/FePt]5/Ag thin films

    Institute of Scientific and Technical Information of China (English)

    FAN Jiu-ping; XU Xiao-hong; JIANG Feng-xian; TIAN Bao-qiang; WU Hai-shun

    2008-01-01

    [SiO2/FePt]5/Ag thin films were deposited by RF magnetron sputtering on the glass substrates and post annealing at 550 ℃for 30 min in vacuum. Vibrating sample magnetometer and X-ray diffraction analyser were applied to study the magnetic properties and microstructures of the films. The results show that without Ag underlayer [SiO2/FePt]5 films deposited onto the glass are FCC disordered; with the addition of Ag underlayer [SiO2/FePt]5/Ag films are changed into L10 and (111) mixed texture. The variation of the SiO2 nonmagnetic layer thickness in [SiO2/FePt]5/Ag films indicates that SiO2-doping plays an important role in improving the order parameter and the perpendicular magnetic anisotropy, and reducing the grain size and intergrain interactions. By controllingSiO2 thickness the highly perpendicular magnetic anisotropy can be obtained in the [SiO2 (0. 6nm)/FePt (3 nm)]5/Ag (50 nm) films and highly (001)-oriented films can be obtained in the [SiO2 (2 nm)/FePt (3 nm)]5/Ag (50 nm) films.

  9. A sensitive glucose biosensor based on Ag@C core–shell matrix

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xuan; Dai, Xingxin; Li, Jianguo [College of Chemistry, Chemical engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123 (China); Long, Yumei, E-mail: yumeilong@suda.edu.cn [College of Chemistry, Chemical engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123 (China); The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou (China); Li, Weifeng, E-mail: liweifeng@suda.edu.cn [College of Chemistry, Chemical engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123 (China); Tu, Yifeng [College of Chemistry, Chemical engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123 (China); The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou (China)

    2015-04-01

    Nano-Ag particles were coated with colloidal carbon (Ag@C) to improve its biocompatibility and chemical stability for the preparation of biosensor. The core–shell structure was evidenced by transmission electron microscope (TEM) and the Fourier transfer infrared (FTIR) spectra revealed that the carbon shell is rich of function groups such as − OH and − COOH. The as-prepared Ag@C core–shell structure can offer favorable microenvironment for immobilizing glucose oxidase and the direct electrochemistry process of glucose oxidase (GOD) at Ag@C modified glassy carbon electrode (GCE) was realized. The modified electrode exhibited good response to glucose. Under optimum experimental conditions the biosensor linearly responded to glucose concentration in the range of 0.05–2.5 mM, with a detection limit of 0.02 mM (S/N = 3). The apparent Michaelis–Menten constant (K{sub M}{sup app}) of the biosensor is calculated to be 1.7 mM, suggesting high enzymatic activity and affinity toward glucose. In addition, the GOD-Ag@C/Nafion/GCE shows good reproducibility and long-term stability. These results suggested that core–shell structured Ag@C is an ideal matrix for the immobilization of the redox enzymes and further the construction of the sensitive enzyme biosensor. - Highlights: • Enhanced direct electrochemistry of GOD was achieved at Ag@C modified electrode. • A novel glucose biosensor based on Ag@C core–shell structure was developed. • The designed GOD-Ag@C/Nafion/GCE biosensor showed favorable analysis properties. • The biosensor is easy to prepare and can be applied for real sample assay.

  10. A sensitive glucose biosensor based on Ag@C core–shell matrix

    International Nuclear Information System (INIS)

    Nano-Ag particles were coated with colloidal carbon (Ag@C) to improve its biocompatibility and chemical stability for the preparation of biosensor. The core–shell structure was evidenced by transmission electron microscope (TEM) and the Fourier transfer infrared (FTIR) spectra revealed that the carbon shell is rich of function groups such as − OH and − COOH. The as-prepared Ag@C core–shell structure can offer favorable microenvironment for immobilizing glucose oxidase and the direct electrochemistry process of glucose oxidase (GOD) at Ag@C modified glassy carbon electrode (GCE) was realized. The modified electrode exhibited good response to glucose. Under optimum experimental conditions the biosensor linearly responded to glucose concentration in the range of 0.05–2.5 mM, with a detection limit of 0.02 mM (S/N = 3). The apparent Michaelis–Menten constant (KMapp) of the biosensor is calculated to be 1.7 mM, suggesting high enzymatic activity and affinity toward glucose. In addition, the GOD-Ag@C/Nafion/GCE shows good reproducibility and long-term stability. These results suggested that core–shell structured Ag@C is an ideal matrix for the immobilization of the redox enzymes and further the construction of the sensitive enzyme biosensor. - Highlights: • Enhanced direct electrochemistry of GOD was achieved at Ag@C modified electrode. • A novel glucose biosensor based on Ag@C core–shell structure was developed. • The designed GOD-Ag@C/Nafion/GCE biosensor showed favorable analysis properties. • The biosensor is easy to prepare and can be applied for real sample assay

  11. Synthesis and characterization of nanostructured Ag on porous titania

    International Nuclear Information System (INIS)

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

  12. 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...

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  14. 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.

  15. Spin coating of Ag nanoparticles: Effect of reduction

    Energy Technology Data Exchange (ETDEWEB)

    Ansari, A. A., E-mail: sdsartale@physics.unipune.ac.in; Sartale, S. D., E-mail: sdsartale@physics.unipune.ac.in [Thin Films and Nanomaterials Laboratory, Department of Physics, University of Pune, Pune - 411007 (India)

    2014-04-24

    A surfactant free method for the growth of Ag nanoparticles on glass substrate by spin coating of Ag ions solution followed by chemical reduction in aqueous hydrazine hydrate (HyH) solution has been presented. Appearance of surface plasmon resonance confirms the formation of Ag nanoparticles. Morphology and absorbance spectra of Ag nanoparticles films are used to examine effect of hydrazine concentration on the growth of Ag nanoparticles. SEM images show uniformly distributed Ag nanoparticles. Rate constant was found to be dependent on HyH concentration as a consequence influence particle size.

  16. 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.

  17. Effect of MnO2 morphology on the catalytic oxidation of toluene over Ag/MnO2 catalysts

    Science.gov (United States)

    Li, Jiamin; Qu, Zhenping; Qin, Yuan; Wang, Hui

    2016-11-01

    The Ag/MnO2 catalysts with different morphologies (wire-like, rod-like and tube-like) are used as toluene oxidation catalysts in an attempt to investigate how the structures of support affect the interaction of Ag and MnO2, and thus the toluene catalytic activity. Analysis by TEM, H2-TPR and XPS measurements reveals that the structures of MnO2 influence the particle size and dispersion of silver particles and the combination of silver particles with MnO2. Meanwhile, the addition of Ag regulates the performance of MnO2. The small particle size and hemispherically shaped Ag particles are easily to form and homogeneously dispersed on the surface of wire-like MnO2. And this specific form of Ag shows the strongest interaction with MnO2, which promotes the low-temperature reducibility of support and generated more lattice oxygen in metal oxides. The Ag/MnO2 nanowires sample exhibits the highest reactivity for toluene oxidation with a complete conversion at 220 °C. Therefore, the excellent catalytic performance of Ag/MnO2 nanowires catalyst for toluene oxidation is clearly connected with the interaction between the Ag and MnO2, which is determined by the morphology of MnO2 support.

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

    Science.gov (United States)

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

    2015-09-01

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

  19. 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.

  20. Detection of Ag(+) using graphite carbon nitride nanosheets based on fluorescence quenching.

    Science.gov (United States)

    Bian, Wei; Zhang, Hao; Yu, Qing; Shi, Meijuan; Shuang, Shaomin; Cai, Zongwei; Choi, Martin M F

    2016-12-01

    The graphite carbon nitride (g-C3N4) nanosheets were synthesized and applied for the detection of Ag(+) ion in aqueous solutions. Transmission electron microscopy, Fourier infrared spectroscopy, x-ray diffraction, ultraviolet/visible and photoluminescence spectroscopy were used for characterization of g-C3N4 nanosheets. The fluorescence intensity of g-C3N4 nanosheets decreases with the increase in the concentration of Ag(+). The fluorescence probe can be applied for detection of Ag(+). The results show that it has high selectivity to Ag(+) and exhibits a good linearity over the concentration range 0.020-2.0μM with a detection limit of 27nM. Most cations do not have any interference on the detection of Ag(+). The quenching process is assessed and discussed. Finally, the g-C3N4 nanosheets have been successfully used for the detection of Ag(+) in real water samples. The recoveries of spiked water samples are >97%. PMID:27348047

  1. Short Communication: Reassessing the Origin of the HIV-1 CRF02_AG Lineages Circulating in Brazil.

    Science.gov (United States)

    Delatorre, Edson; Velasco-De-Castro, Carlos A; Pilotto, José H; Couto-Fernandez, José Carlos; Bello, Gonzalo; Morgado, Mariza G

    2015-12-01

    HIV-1 CRF02_AG is responsible for at least 8% of the HIV-1 infections worldwide and is distributed mainly in West Africa. CRF02_AG has recently been reported in countries where it is not native, including Brazil. In a previous study including 10 CRF02_AG Brazilian samples, we found at least four independent introductions and two autochthonous transmission networks of this clade in Brazil. As more CRF02_AG samples have been identified in Brazil, we performed a new phylogeographic analysis using a larger dataset than before. A total of 20 Brazilian (18 from Rio de Janeiro and two from São Paulo) and 1,485 African HIV-1 CRF02_AG pol sequences were analyzed using maximum likelihood (ML). The ML tree showed that the Brazilian sequences were distributed in five different lineages. The Bayesian phylogeographic analysis of the Brazilian and their most closely related African sequences (n = 212) placed the origin of all Brazilian lineages in West Africa, probably Ghana, Senegal, and Nigeria. Two monophyletic clades were identified, comprising only sequences from Rio de Janeiro, and their date of origin was estimated at around 1985 (95% highest posterior density: 1979-1992). These results support the existence of at least five independent introductions of the CRF02_AG lineage from West Africa into Brazil and further indicate that at least two of these lineages have been locally disseminated in the Rio de Janeiro state over the past 30 years.

  2. Fabrication of porous 3D flower-like Ag/ZnO heterostructure composites with enhanced photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Yimai; Guo, Na; Li, Linlin; Li, Ruiqing; Ji, Guijuan, E-mail: juanziji@126.com; Gan, Shucai, E-mail: gansc@jlu.edu.cn

    2015-03-30

    Graphical abstract: Porous 3D flower-like Ag/ZnO heterostructural composites were fabricated by hydrothermal and photochemical deposition methods. Such the unique porous 3D structure of Ag/ZnO composites displays excellent photocatalytic activity on Rhodamine B. And the composite of Ag/ZnO is a promising candidate material for future treatment of contaminated water. - Highlights: • Unique porous 3D flower-like Ag/ZnO composites were successfully synthesized. • No pore-directing reagents or surfactants are used in the synthesis of the Ag/ZnO. • Compared with Degussa P25, the Ag/ZnO exhibited superior photocatalytic activity. - Abstract: Porous 3D flower-like Ag/ZnO heterostructural composites were fabricated by hydrothermal and photochemical deposition methods, without using any pore-directing reagents and surfactants. The obtained samples were characterized by XRD, SEM, TEM, XPS, BJH, DRS, and PL spectrum. The experiment results show that the silver nanoparticles successfully load on the surface of assembled ZnO flowers. The TEM and SEM morphologies demonstrated unique porous 3D flower-like structure of Ag/ZnO. Such special structure makes larger surface area and more active sites exposed during the reaction, facilitating the transportation of reactants and products and increasing the reaction rate. The photocatalytic degradation experiments under UV irradiation using Rhodamine B (RhB) as a model dye were executed. The relative results demonstrate that the photocatalytic activity of Ag/ZnO is obviously improved compared with the pure ZnO and the commercial TiO{sub 2} (Degussa P25), the AZ-15 sample has the highest photocatalytic activity. The Ag/ZnO heterostructure composites promoted the separation of photo-induced electrons and holes, which was proved by photoluminescence spectra (PL)

  3. 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.

  4. 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

  5. 超声微乳液法制备Ag/AgCl复合纳米颗粒及其光催化性能研究%Preparation of Ag/AgCl from Ultrasonic Microemulsion and Its Photocatalytic Activity

    Institute of Scientific and Technical Information of China (English)

    胡荣; 任志敏; 陈超; 王智宇

    2012-01-01

    设计了一种全新的微乳液体系,以十二烷基磺酸钠(SDS)、乙醇、正丁醇和异辛烷的混合物作为复合乳化剂,采用超声微乳液法制备了Ag/AgCl复合纳米颗粒.利用SEM和EDS研究样品的形貌、尺寸及表面组成,通过研究样品对甲基橙降解过程的催化作用证明了样品在可见光下的催化活性.重点研究了反应物浓度对Ag/AgCl颗粒尺寸及形貌的影响,结果表明,Ag/AgCl复合纳米颗粒尺寸主要由微乳液尺寸决定,受反应物浓度的影响较小,反映出本工作提出的超声微乳液制备技术具有较高的工艺稳定性.%A new microemulsion system whose emulsifier comprised sodium dodecyl sulfonate, ethanol, n-buta-nol and isooctane was represented firstly. In the new system, a facile, novel ultrasonic microemulsion method was used to prepare Ag/AgCl composite nanoparticles. The morphologies and size and surface composition of the samples were characterized by SEM and EDS. The catalytic activity under visible light of the composite nanoparticles was proved in the process of the decomposition of methyl orange dye. The effects of concentrations of various reactants on the particle size and morphology were investigated primarily. The results show that the sample size and morphology are determined mainly by the size of microemulsion and not particularly sensitive to the variation of the ratio of various reactants, from which we can see that the ultrasonic microemulsion method has a high stability.

  6. Preparation of Ag2O/Ag2CO3/MWNTs composite photocatalysts for enhancement of ciprofloxacin degradation

    Science.gov (United States)

    Wang, Huiqin; Li, Jinze; Huo, Pengwei; Yan, Yongsheng; Guan, Qingfeng

    2016-03-01

    The Ag2O/Ag2CO3/multi-walled carbon nanotube (MWNTs) composite photocatalysts were prepared by calcination of the obtained precipitate. The structures and morphology of as-prepared composite photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, X-ray photoelectron spectroscopy (XPS). The Ag2O/Ag2CO3/MWNTs composite photocatalysts exhibit higher degradation rate of ciprofloxacin (CIP) than the pure Ag2CO3, Ag2O/Ag2CO3 and Ag2CO3/MWNTs under visible light irradiation. The amount of loaded Ag2CO3 onto MWNTs and calcined time for Ag2CO3/MWNTs were systematically investigated, and the optimal amount of loaded Ag2CO3 and calcined time of Ag2CO3/MWNTs are 150 wt% and 10 min, respectively. The highest photocatalytic degradation rate of CIP could reach 76% under optimal conditions. The active species trapping experiments were also analyzed, the results show that the holes are main contributor for the degradation processes of CIP, furthermore the electrons, rad O2- and rad OH are also crucially influenced the photocatalytic degradation processes of CIP. The possible photocatalytic processes of CIP with Ag2O/Ag2CO3/MWNTs composite photocatalyst are also proposed.

  7. Ultrasonic-assisted preparation of novel ternary ZnO/Ag3VO4/Ag2CrO4 nanocomposites and their enhanced visible-light activities in degradation of different pollutants

    Science.gov (United States)

    Pirhashemi, Mahsa; Habibi-Yangjeh, Aziz

    2016-05-01

    Novel ternary ZnO/Ag3VO4/Ag2CrO4 nanocomposites were successfully fabricated via preparation of ZnO/Ag3VO4 followed by coupling of it with Ag2CrO4 through facile ultrasonic-assisted method. The resultant samples were carefully characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive analysis of X-rays, UV-vis diffuse reflectance spectroscopy, Fourier transform-infrared spectroscopy, and photoluminescence techniques. Photocatalytic activity for degradation of organic dyes, including rhodamine B, methylene blue, and methyl orange was examined under visible-light irradiation. Among the prepared samples, the ternary nanocomposite with 20% of Ag2CrO4 demonstrated the superior activity. This nanocomposite showed 10.6, 2.9, and 3.0-folds greater activity compared to ZnO, ZnO/Ag2CrO4, and ZnO/Ag3VO4, respectively. The enhanced activity was attributed to more harvesting of the visible-light irradiation and efficiently separation of the photogenerated charge carriers in the ternary nanocomposites. To understand efficiently separation of the charge carriers, a plausible diagram was proposed based on formation of tandem n-n heterojunctions.

  8. 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.

  9. Preparation of CdS/Ag2 S Composite Photocatalyst and Its Photocatalytic Performance%CdS/Ag2S复合光催化剂的制备及其光催化性能的研究

    Institute of Scientific and Technical Information of China (English)

    艾东; 赵荣祥; 李秀萍; 徐铸德

    2015-01-01

    采用沉积-沉淀法制备了一系列不同 Ag2 S 负载量的 CdS/Ag2 S 复合光催化剂,通过 X 射线衍射、扫描电镜、紫外-可见光谱等手段对催化剂进行了表征。结果表明,CdS/Ag2 S 系列样品的颗粒粒径小于 CdS 的颗粒粒径。以可见光为光源,考察了 Ag2 S 负载量对 CdS/Ag2 S 系列样品的光催化性能的影响。结果表明,当 Ag2 S 负载量为10.0%、反应时间为220 min 时,罗丹明 B 的降解率达到最高,为71%。CdS/Ag2 S 复合光催化剂能够显著减少光生电子-空穴对的重新结合次数,因此其光催化降解罗丹明 B 的能力要高于 CdS。%Series of CdS/Ag2 S composite photocatalysts with different Ag2 S concentrations were prepared by the precipitation-grinding method.The prepared samples were characterized by X-ray diffraction,scanning electron microscopy,UV-visible spectroscopy,and photoluminescence spectroscopy.The catalyst particle size of CdS/Ag2 S was proved to be smaller than the catalyst particle size of CdS.The reaction system was set under visible light irradiation to study the influence to the photocatalytic performance of CdS/Ag2 S with different condentration of Ag2 S.The CdS/Ag2 S composite photocatalyst with the weight of 10.0% concentration of Ag2 S showed the highest photocatalytic activity and the degradation of Rhodamine B was 71%.The presence of Ag2 S also restrained the recombination rate of e-/h+ pairs.The photocatalytic activity of degradation of Rhodamine B was significantly improving.

  10. Photo-enhanced salt-water splitting using orthorhombic Ag8SnS6 photoelectrodes in photoelectrochemical cells

    Science.gov (United States)

    Cheng, Kong-Wei; Tsai, Wei-Tseng; Wu, Yu-Hsuan

    2016-06-01

    Orthorhombic Ag8SnS6 photoelectrodes are prepared on various substrates via reactive sulfurization using the radio-frequency magnetron sputtering of silver-tin metal precursors. Evaluations of the photoelectrochemical performances of Ag8SnS6 photoelectrodes with various levels of silver content are carried out in various aqueous solutions. X-ray diffraction patterns and Hall measurements of samples after a three-stage sulfurization process show that all samples are the pure orthorhombic Ag8SnS6 phase with n-type conductivity. The energy band gaps, carrier concentrations, and mobilities of samples on glass substrates are 1.31-1.33 eV, 7.07 × 1011-8.52 × 1012 cm-3, and 74.9-368 cm2 V-1 s-1, respectively, depending on the [Ag]/[Ag+Sn] molar ratio in samples. The highest photoelectrochemical performances of orthorhombic Ag8SnS6 photoelectrodes in aqueous 0.35 M Na2S + 0.25 M K2SO3 and 0.5 M NaCl solutions are respectively 2.09 and 2.5 mA cm-2 at an applied voltages of 0.9 and 1.23 V vs. a reversible hydrogen electrode under light irradiation with a light intensity of 100 mW cm-2 from a 300-W Xe lamp.

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

    Institute of Scientific and Technical Information of China (English)

    胡鹏; 谭浩; 龚沈光

    2011-01-01

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

  12. Magnetic anisotropy studies on pulsed electrodeposited Ni/Ag/Ni trilayer

    Energy Technology Data Exchange (ETDEWEB)

    Dhanapal, K.; Revathy, T.A.; Raj, M. Anand [Materials Science Centre, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai 600 025 (India); Narayanan, V. [Department of Inorganic Chemistry, University of Madras, Guindy Campus, Chennai 600 025 (India); Stephen, A., E-mail: stephen_arum@hotmail.com [Materials Science Centre, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai 600 025 (India)

    2014-09-15

    Highlights: • Ni/Ag/Ni layered film has been prepared using pulsed electrodeposition method. • Crystalline nature of layered films is confirmed using XRD. • Magnetic easy axis is observed to be parallel to the plane of the film. • Magnetic anisotropy change is dependent on number of layers. • Ni/Ag/Ni layered film shows higher anisotropy energy than pure Ni film. - Abstract: The pulsed electrodeposition method was employed for the deposition of pure Ni, Ni/Ag and Ni/Ag/Ni films due to its greater advantages while comparing with other methods. The X-ray diffraction pattern confirms the formation of fcc structure for both nickel and silver. The cross sectional scanning electron microscopy shows the layer formation in Ni/Ag and Ni/Ag/Ni films. The metallic nature of the nickel and silver were also confirmed using X-ray photoelectron spectroscopy. The magnetic anisotropy behaviour was studied using vibrating sample magnetometer which gives that the easy axis is in plan of the film for all the film.

  13. Ag/CdS heterostructural composites: Fabrication, characterizations and photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yang [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan, Shanxi 030024 (China); College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024 (China); Chi, Mei [Institute of Metal Research, Chinese Academy of Sciences, Shenyang, Liaoning 110016 (China); Dong, Hailiang; Jia, Husheng; Xu, Bingshe [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan, Shanxi 030024 (China); College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024 (China); Zhang, Zhuxia, E-mail: zhangzhuxia@tyut.edu.cn [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan, Shanxi 030024 (China); College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024 (China)

    2014-09-15

    Highlights: • Novel Ag/CdS core–shell heterostructural composites were fabricated using a two-step chemical method. • A formation mechanism of Ag/CdS heterostructural composites. • The photocatalytic activity of Ag/CdS heterostructural composites was found to be improved. • PL emissions are markedly quenched in the Ag/CdS composites than in CdS nanoparticles. - Abstract: Ag/CdS heterostructural materials were successfully synthesized by ultrasound-assisted polyols and hydrothermal method. Under hydrothermal condition, thiourea adsorbed on Ag nanowires releases S{sup 2−} ions, which react with vicinal Cd{sup 2+} ions to form CdS clusters on Ag nanowires. Thereafter, the Ag/CdS composites grow into core–shell structure through CdS aggregation, Ostwald ripening, and preferential growth. The obtained core–shell structures and morphologies were investigated by XRD, SEM, and TEM; the experimental results indicate that the composites are composed of Ag nanowires serving as the core and CdS particles as the shell. The photocatalytic property of Ag/CdS core–shell materials was then investigated in detail. Comparing studies on the degradation of methylene blue were employed by using pure CdS, pure Ag, and Ag/CdS composites, respectively. The results show that the Ag/CdS composites possess higher photocatalytic degradation efficiency. Moreover, the Ag/CdS composites show improved stability, and the photocatalytic activity remains almost unchanged after four recycles. The enhanced photocatalytic effect for Ag/CdS composites is mainly attributed to the photogenerated electron transfer from CdS to Ag nanowire, while photogenerated holes still remain in CdS's valence band. Consequently, the effective separation of photogenerated electrons and holes and the resulting OH radicals improve the photocatalytic efficiency of Ag/CdS composites greatly.

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

    Science.gov (United States)

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

    2006-05-01

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

  15. Antibacterial biodegradable Mg-Ag alloys

    Directory of Open Access Journals (Sweden)

    D Tie

    2013-06-01

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

  16. AGS experiments -- 1991, 1992, 1993

    International Nuclear Information System (INIS)

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

  17. AGS experiments - 1994, 1995, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Depken, J.C.

    1997-01-01

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

  18. AGS experiments - 1994, 1995, 1996

    International Nuclear Information System (INIS)

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

  19. structural and magnetic properties of Fe(20Å /Ag(xÅ/Fe(20Å hetro-multilayers

    Directory of Open Access Journals (Sweden)

    P Ghahramaninezhad

    2015-07-01

    Full Text Available We have deposited Fe/Ag/Fe multilayer by physical vapor deposition (PVDmethod in different Ag thickness as spacer working in a vacuum of 2×10-6mbar. The structural properties , magnetic response of the samples at low temperatures and room temperature was investigated by XRD, physical properties measurement system (PPMS and vibrating sample magnetometer (VSM respectively. Hysteresis loops show that the easy axis of magnetization is in plane of the film . Also the magnetization and Hc of samples decrease with increasing temperature.

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

    Science.gov (United States)

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

    2015-03-01

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

  1. Study on Amorphous Ionic Conductors of AgI-Ag2WO4 Material%AgI-Ag2WO4非晶离子导体材料的研究

    Institute of Scientific and Technical Information of China (English)

    王禹; 陈旻; 郜嘉平; 李云鹏; 胡行方

    2001-01-01

    通过淬火工艺制备了4AgI.Ag2WO4材料,并使用X射线衍射、热示差等分析方法研究了该种材料的结构和导电性。结果表明,4AgI.Ag2WO4材料是非晶态的玻璃,并具有很高的离子导电率。%Amorphous AgI.Ag2WO4 material in the silver salt-silverorthooxysalt systems was prepared by using quenching method and studied by using RAX-10 X-Ray diffractometer and conductance bridge . DTA was also used to assist in characterizing this material. The results show that 4AgI.Ag2WO4 material is amorphous glass and is passessed of very high ionic couductivity.

  2. Oxidative Stress Mechanisms Caused by Ag Nanoparticles (NM300K are Different from Those of AgNO3: Effects in the Soil Invertebrate Enchytraeus Crypticus

    Directory of Open Access Journals (Sweden)

    Maria J. Ribeiro

    2015-08-01

    Full Text Available The mechanisms of toxicity of Ag nanoparticles (NPs are unclear, in particular in the terrestrial environment. In this study the effects of AgNP (AgNM300K were assessed in terms of oxidative stress in the soil worm Enchytraeus crypticus, using a range of biochemical markers [catalase (CAT, glutathione peroxidase (GPx, glutathione S-transferase (GST, glutathione reductase (GR, total glutathione (TG, metallothionein (MT, lipid peroxidation (LPO]. E. crypticus were exposed during 3 and 7 days (d to the reproduction EC20, EC50 and EC80 levels of both AgNP and AgNO3. AgNO3 induced oxidative stress earlier (3 d than AgNP (7 d, both leading to LPO despite the activation of the anti-redox system. MT increased only for AgNP. The Correspondence Analysis showed a clear separation between AgNO3 and AgNP, with e.g. CAT being the main descriptor for AgNP for  7 d. LPO, GST and GPx were for both 3 and 7 d associated with AgNO3, whereas MT and TG were associated with AgNP. These results may reflect a delay in the effects of AgNP compared to AgNO3 due to the slower release of Ag+ ions from the AgNP, although this does not fully explain the observed differences, i.e., we can conclude that there is a nanoparticle effect.

  3. 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.

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

    International Nuclear Information System (INIS)

    Highlights: • Cu-rich nanoprecipitates are formed in the presence of Ag. • Bainite precipitation is shifted to higher temperatures in the Cu–11%Al–10%Mn–3%Ag alloy. • The eutectoid α phase and bainite α1 phase compete by the Cu atoms during precipitation process. - Abstract: The formation of Ag-rich precipitates in the Cu–11%Al–10%Mn–3%Ag alloy initially quenched from 1123 K was analyzed. The results showed that nanoprecipitates of a Cu-rich phase are produced at about 523 K. In higher temperatures these nanoparticles grow and the relative fraction of Ag dissolved in it is increased, thus forming the Ag-rich phase

  5. X-ray irradiation-induced changes in (PVA-PEG-Ag) polymer nanocomposites films

    Science.gov (United States)

    Nouh, S. A.; Benthami, K.; Abutalib, M. M.

    2016-02-01

    The effects of X-ray irradiation on the structural, thermal and optical properties of polyvinyl alcohol-polyethylene glycol-silver (PVA-PEG-Ag) nanocomposites have been investigated. The samples of nanocomposites were prepared by adding Ag nanoparticles with 5 wt% to the (PVA-PEG) blend. The films of 0.05 mm thickness were prepared by the casting method. These films were irradiated with X-ray doses ranging from 20 to 200 kGy. The resultant effect of X-ray irradiation on the structural properties of PVA-PEG-Ag has been investigated using X-ray diffraction and Fourier transform infrared spectroscopy. Also, thermal property studies were carried out using thermogravimetric analysis. Further, the transmission of the PVA-PEG-Ag samples and any color changes were studied. Fourier transform infrared spectroscopy measurements showed that the crosslinking is the dominant mechanism at the dose range 50-200 kGy. This led to a more compact structure of PVA-PEG-Ag samples, which resulted in an improvement in its thermal stability with an increase in the activation energy of thermal decomposition. Moreover, the color intensity ΔE was greatly increased with an increase in the dose, and was accompanied by a significant increase in the yellow color component.

  6. Tailoring the size and distribution of Ag nanoparticles in silica glass by defects

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yitao, E-mail: yangyt@impcas.ac.cn [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhang, Chonghong; Song, Yin; Gou, Jie; Zhang, Liqing [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhang, Hengqing; Liu, Juan; Xian, Yongqiang [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Ma, Yizhun [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2014-02-15

    The composites embedded with metallic nanoparticles show large nonlinear optical susceptibility and strong surface plasmon resonance absorption, which enable potential application in opto-electronics. Ion implantation has been proven to be a powerful technique of synthesis of metallic nanoparticles due to its versatility and compatibility. However, the synthesis of nanoparticles by ion implantation inevitably leads to a broad size distribution due to Ostwald ripening process. The broad size distribution has a negative effect on improving the figure of merits for nonlinear optics. In this paper, we tried to introduce defects in silica glass to act as pre-nucleation centers to mediate the size and distribution of Ag nanoparticles. In experiment, the silica glass samples were pre-irradiated by 200 keV Ar ions to fluences of 0.8, 2.0 and 5.0 × 10{sup 16} ions/cm{sup 2}, and then 200 keV Ag ions were implanted into the pre-irradiated samples to fluence of 2.0 × 10{sup 16} ions/cm{sup 2}. UV–VIS results show that the absorbance intensity of Ag SPR peak initially increases and then decreases with pre-irradiation fluence, which implies the change in size and density of Ag nanoparticles in samples. TEM results verify that Ag nanoparticles in the sample pre-irradiated to the fluence of 0.8 × 10{sup 16} ions/cm{sup 2} grow bigger and distribute in a relatively narrow region comparing with that without pre-irradiation. With further increase of pre-irradiation fluence, the size of Ag nanoparticles shows a depth dependent distribution. A boundary can be clear seen at the depth of 110 nm, larger Ag nanoparticles disperse in region shallower than 110 nm, and smaller Ag nanoparticles disperse in the region deeper than 110 nm. The average size of Ag nanoparticles initially increases and then decreases with pre-irradiation fluence. Therefore, the introduction of defects by pre-irradiation could be an effective way to tailor the size and distribution of metallic nanoparticles in

  7. 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.

  8. Morphological and optical data of AgNW embedded transparent conductive layer.

    Science.gov (United States)

    Kim, Hong-Sik; Patel, Dipal B; Patel, Malkeshkumar; Kim, Joondong

    2016-12-01

    In this data article, morphological and optical data of AgNW encapsulated between ITO layers are presented to get insights into our article (DOI:10.1016/j.solmat.2016.04.038; Hong-Sik Kim, Pankaj Yadav, Malkeshkumar Patel, Hyunki Kim, Kavita Pandey, Joondong Kim, 2016) [1]. SEM images for the formation of AgNWs networks by number of spin coating are also presented. SEM photographs showing the surface morphologies before and after rapid thermal treatment of prepared samples have been presented. Apart from morphological data set, optical characteristics of this type of samples are given. The comparison plots of optical reflectance from AgNW encapsulated between ITO layers and bare ITO are given between the wavelength ranges from 300 to 1100 nm. At the end, transmittance and reflectance curves of native glass substrates used in this study are presented. PMID:27656670

  9. Synthesis and Characterization of Ag2S Layers Formed on Polypropylene

    Directory of Open Access Journals (Sweden)

    Valentina Krylova

    2013-01-01

    Full Text Available Silver sulphide, Ag2S, layers on the surface of polypropylene (PP film was formed by chemical bath deposition method (CBD. Film samples were characterised by X-ray photoelectron spectroscopy (XPS, attenuated total reflection Fourier transform infrared (ATR-FTIR spectroscopy, scanning electron microscopy (SEM, atomic force microscopy (AFM, and X-ray diffraction analysis (XRD. The surface morphology, texture, and uniformity of the silver sulphide layers were formed on PP surface dependent on the number of polymer immersions in the precursor solution. XPS analysis confirmed that on the surface of the polypropylene film, a layer of Ag2S was formed. ATR-FTIR and FTIR spectra analysis showed that the surface of Ag2S layers is slightly oxidized. All prepared layers gave multiple XRD reflections, corresponding to monoclinic Ag2S (acanthite. The Ag2S layer on polypropylene was characterized as an Ag+ ion selective electrode in terms of potential response and detection limit. The electrode was also tested as an end-point electrode for argentometric titration of thiamine hydrochloride.

  10. Synthesis of Ag nanoparticles for the electrochemical detection of anticancer drug flutamide

    Institute of Scientific and Technical Information of China (English)

    Farzaneh Ahmadi; Jahan Bakhsh Raoof; Reza Ojani; Mehdi Baghayeri; Moslem Mansour Lakouraj; Hamed Tashakkorian

    2015-01-01

    Ag nanoparticles were synthesized on the surface of a glassy carbon electrode modified with p‐tert‐butylcalix[4]arene and p‐tert‐butylcalix[6]arene by the deposition of Ag+at an open circuit potential followed by the electrochemical reduction of the Ag+. The presence of the calixarene layer on the electrode surface controlled the particle size and prevented agglomeration. Cyclic voltam‐metry showed that the Ag nanoparticles on the modified glassy carbon electrode had good catalytic ability for the reduction of flutamide. The effects of calixarene concentration, potential applied for the reduction of Ag+, number of calixarene layers, and pH value on the electrocatalytic activity of the Ag nanoparticles were investigated. The modified electrode had a linear range in differential pulse voltammetry of 10−1000 µmol/L with a detection limit of 9.33 µmol/L for flutamide at an S/N=3. The method was applied to the detection of flutamide in practical samples.

  11. On the long-term behaviour of 110mAg in the soil-plant system and its transfer from feed to pig

    International Nuclear Information System (INIS)

    The long-term transfer of radiosilver from soil to pasture grass was investigated over 5 years on an undisturbed pasture using stable silver (109Ag) isotope as a tracer. The silver content of all the samples was determined by neutron activation analysis. The temporal change of the Ag+ uptake into forage was negligible mainly due to the low mobility of silver in the soil (orthi-humic-gleysol). The mean grass/soil concentration factor levelled out at 1.3±0.5x10-2 during the 59-month observation period. In a 30-day feeding experiment with pigs, 110mAg was used to determine distribution and retention. The internal distribution of 110mAg showed the liver to be the most contaminated tissue. The highest 110mAg retention was found in the brain. The biological half-lives obtained for the liver and the brain were 35 and 136 days, respectively

  12. Preparation and antibacterial activity of titanium nanotubes loaded with Ag nanoparticles in the dark and under the UV light

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chanjuan; Feng, Bo, E-mail: fengbo@swjtu.edu.cn; Li, Yiting; Tan, Jing; Lu, Xiong; Weng, Jie

    2013-09-01

    Highly ordered anatase-type titanium nanotubes (TNTs) arrays were prepared on the surface of titanium by anodization and subsequently heat treatment at 450 °C for 5 h. Three different diameters of TNTs (50 nm, 75 nm, 100 nm) were fabricated via the voltage changed. Then Ag was loaded on these TNTs through a photo-reduction method of AgNO{sub 3} solution. Ag particles with the size of approximately 10 nm were uniformly distributed on the surface of TNTs. Samples were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, atomic absorption spectrometry and contact angle test. Meanwhile, the antibacterial activities of Ag-loaded TiO{sub 2} nanotubes (TNTs-Ag) were evaluated through antibacterial experiment against both Escherichia coli and Staphylococcus aureus in the dark and under the UV light (λ = 365 nm) irradiation respectively. The results indicated that under the UV light TNTs-Ag had higher antibacterial activities to the two bacteria than TNTs, though the later also showed antibacterial ability. While in the dark environment, the loading of Ag nanoparticles largely enhanced the antibacterial activities of the titanium nanotubes. In addition, the antibacterial efficiencies of all samples increased with increase of nanotube diameters both in the dark and under the UV light. Therefore, TNTs loaded with Ag nanoparticles are expected to be well suited for endo-prosthetic applications due to their excellent antibacterial activities in the dark. And their antibacterial efficiencies can be controlled by adjusting diameters of TNTs, distribution and size of Ag nanoparticles.

  13. Visible-light photoactive Ag-AgBr/α-Ag3VO4 nanostructures prepared in a water-soluble ionic liquid for degradation of wastewater

    Science.gov (United States)

    Padervand, Mohsen

    2016-03-01

    Ag-AgBr/α-Ag3VO4 photocatalysts, prepared by an ionic liquid-assisted precipitation method, were used as an efficient visible light-driven photocatalytic system for removal of wastewater and pathogenic bacteria from the aqueous medium. X-ray diffraction powder, diffuse reflectance spectroscopy, Fourier transform infrared, scanning electron microscopy, and nitrogen adsorption-desorption isotherm (BET) analysis methods were used to characterize the nanostructures. Photodegradation mechanism was investigated and the results showed that the prepared samples were too efficient for the degradation of Acid Blue 92 (AB92) azo dye, and E. coli cells under visible light. The photogenerated electron-hole pairs reacted with the species in the solution and produced super active radicals such as {{O}}{{{H}}^ \\cdot } , {{H}}{{{O}}^ \\cdot }_{{2}} , and {{{O}}^{ \\cdot - }}_{{2}} which are responsible for the degradation of the environmental pollutions. TEM images were used to clarify the antibacterial activity of the products. Finally, as a practical application of the prepared photocatalysts, their ability evaluated for degradation of a real wastewater sample which was provided from the textile industries.

  14. Geochemistry of the Patricia Zn-Pb-Ag Deposit (paguanta, NE Chile)

    Science.gov (United States)

    Chinchilla Benavides, D.; Merinero Palomares, R.; Piña García, R.; Ortega Menor, L.; Lunar Hernández, R.

    2013-12-01

    The Patricia Zn-Pb-Ag ore deposit is located within the Paguanta mining project, situated at the northern end of the Andean Oligocene Porphyry Copper Belt of Chile. The sulfide mineralization occurs as W-E oriented veins hosted in volcanic rocks, mainly andesite (pyroclastic, ash and lavas), of Upper Cretaceous to Middle Tertiary age. The ore mineralogy (obtained by EMPA analyses) comprises in order of abundance, pyrite, sphalerite (5.5 - 10.89 wt % Fe, 9.8-19 % molar FeS and 0.52 wt % Cd), galena, arsenopyrite, chalcopyrite and Ag-bearing sulfosalts. The veins show a zoned and banded internal structure with pyrite at the edges and sphalerite in the center. The Ag occurs mostly as Ag-Cu-Sb sulfosalts, in order of abundance: series freibergite - argentotennantite -polybasite and stephanite. Other minor Ag phases such as argentite, pyrargirite and diaphorite were also identified. These Ag phases are typically associated with the base-metal sulfides. Freibergite occurs filling voids within sphalerite, chalcopyrite and at the contact between sphalerite and galena. Polybasite, stephanite, pyrargirite and argentite are mostly in close association with freibergite. In the case of diaphorite, it commonly occurs filling voids between galena crystals or as inclusions within galena. Some minor Ag-bearing sulfosalts are also identified between pyrite crystals. The alteration minerals are dominated by chlorite, illite and kaolinite. The gangue minerals consist of quartz and carbonates identified by XRD as kutnahorite. We obtained linear correlation statistically significant only for Ag, As Au, Cd, Cu, Pb, Sb and Zn and therefore we generated an enhanced scatter plot matrix of these elements. Bulk rock analyses (ICP/MS and XRF) of drill cores show that Ag is strongly and positively correlated with Pb and As, moderately with Cd, Sb, Au and Zn and weakly with Cu, while Au is moderately and positively correlated with Ag, As, Cd, Sb and Zn and weakly with Cu and Pb. These results

  15. Synthesis, structural characterisation and antibacterial activity of Ag{sup +}-doped fluorapatite nanomaterials prepared by neutralization method

    Energy Technology Data Exchange (ETDEWEB)

    Stanić, Vojislav, E-mail: voyo@vinca.rs [University of Belgrade, Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia); Radosavljević-Mihajlović, Ana S. [University of Belgrade, Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia); Živković-Radovanović, Vukosava [University of Belgrade, Faculty of Chemistry, P.O. Box 51, 11158 Belgrade (Serbia); Nastasijević, Branislav; Marinović-Cincović, Milena; Marković, Jelena P.; Budimir, Milica D. [University of Belgrade, Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia)

    2015-05-15

    Graphical abstract: - Highlights: • The neutralization method has been used for synthesis of silver-doped fluorapatite powders. • Particles of silver-doped fluorapatite samples are of nano size and homogenous in composition. • The Ag{sup +}-doped fluorapatite samples showed antibacterial effect against Kllebsiela pneumoniae, Staphylococcus aureus and Micrococcus luteus. • AFM studies showed that silver-doped sample causes considerable morphological changes of tested bacterial cells. - Abstract: Silver doped fluorapatite nanopowders were synthesised by neutralization method, which consists of dissolving Ag{sub 2}O in solution of HF and H{sub 3}PO{sub 4} and addition to suspension of Ca(OH){sub 2}. The powder XRD, SEM and FTIR studies indicated the formation of a fluorapatite nanomaterials with average length of the particles is about 80 nm and a width of about 15 nm. The FTIR studies show that carbonate content in samples is very small and carbonte ions substitute both phosphate and hydroxyl groups in the crystal structure of samples, forming AB-type fluorapatite. Antibacterial studies have demonstrated that all Ag{sup +}-doped fluorapatite samples exhibit bactericidal effect against pathogens: Staphylococcus aureus, Micrococcus luteus and Kllebsiela pneumoniae. Antibacterial activity increased with the increase of Ag{sup +} in the samples. The atomic force microscopy studies revealed extensive damage to the bacterial cell envelops in the presence of Ag{sup +}-doped fluorapatite particles which may lead to their death. The synthesized Ag{sup +}-doped fluorapatite nanomaterials are promising as antibacterial biomaterials in orthopedics and dentistry.

  16. 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.

  17. 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...

  18. A highly sensitive non-enzymatic glucose sensor based on bimetallic Cu-Ag superstructures.

    Science.gov (United States)

    Li, Hua; Guo, Chun-Yan; Xu, Cai-Ling

    2015-01-15

    Bimetallic Cu-Ag superstructures were successfully fabricated for the first time by using the natural leaves as reducing agent through a facile one-step hydrothermal process. Morphology, structure and composition of the Cu-Ag superstructures were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and inductively coupled plasma-optical emission spectroscopy (ICP-OES), respectively. The results reveal that the Cu-Ag superstructure is bimetallic nanocomposite constructed by nanoparticles with low Ag content and shows a rough surface and porous flexural algae-like microstructure. By using a three-dimensional nickel foam as the scaffold, a novel non-enzymatic glucose sensor based on Cu-Ag nanocomposites has been fabricated and applied to non-enzymatic glucose detection. The as-prepared Cu-Ag nanocomposites based glucose sensor displays distinctly enhanced electrocatalytic activity compared to those obtained with pure Cu nanomaterials prepared with a similar procedure, revealing a synergistic effect of the matrix Cu and the doped Ag. Cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy indicate that the Cu-Ag superstructures based glucose sensor displays a fascinating sensitivity up to 7745.7 μA mM(-1) cm(-2), outstanding detection limit of 0.08 μM and fast amperometric response (glucose detection. Furthermore, the sensor also exhibits significant selectivity, excellent stability and reproducibility, as well as attractive feasibility for real sample analysis. Because of its excellent electrochemical performance, low cost and easy preparation, this novel electrode material is a promising candidate in the development of non-enzymatic glucose sensor. PMID:25113052

  19. 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.

  20. Microstructural study of Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-x}/Ag samples irradiated with {sup 60}Co {gamma} rays at high doses

    Energy Technology Data Exchange (ETDEWEB)

    Rangel, R. [Programa de Postgrado en Fisica de Materiales, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Apartado Postal 2681, CP 22800, Ensenada, BC (Mexico); Galvan, D.H. [CECIMAC-UNAM, Apartado Postal 2681, CP 22800, Ensenada, BC (Mexico); Adem, E. [Instituto de Fisica-UNAM, Apartado Postal 20-364, CP 01000, Mexico DF (Mexico); Bartolo-Perez, P. [CINVESTAV-IPN Unidad Merida, Departamento de Fisica Aplicada, Merida, Yucatan (Mexico); Maple, M.B. [Physics Department and Institute for Pure and Applied Physical Sciences, La Jolla, CA (United States)

    1998-06-01

    We have investigated the damage induced by irradiation in Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-x} silver added samples. The samples were prepared with 0 and 6.5 wt% of silver and irradiated by high-energy {gamma} irradiation (50-150 Mrad). The roles of silver and dosage irradiation are discussed in terms of their effects on microstructure, crystallinity, critical temperature (T{sub c}) and zero-resistance temperature (T{sub 0}). After irradiation, T{sub c} decreased while the room-temperature electrical resistance increased by a factor of 8 for some of the samples. The difference in T{sub 0} between irradiated and non-irradiated YBCO samples was of the order of 10 K. We have found that the difference is bigger for silver-added samples. We have also observed several changes in diffraction patterns of YBCO and YBCO-silver samples. SEM images, EDS and XPS analysis showed that silver resided inside the grains as single atoms and as metallic clusters. The relative concentrations of the elements in samples were quantified by Auger electron spectroscopy. The values showed a gradual increase for radiation doses ranging between 0 and 100 Mrad. For doses up to 100 Mrad, J{sub c} decreased because of the weak-link breakage induced by high doses of {gamma} rays. (author)

  1. Fabrication of AgAu alloy-TiO2 core-shell nanoparticles and their photocatalytic properties

    Science.gov (United States)

    Zhang, Xiao-yu; Yuan, Shu-long; Yuan, Yu-zhen; Li, Xue

    2015-01-01

    In this paper, for improving the photocatalytic efficiency of titania (TiO2) nanoparticles (NPs), AgAu alloy-TiO2 core-shell NPs are fabricated via a sol-gel (SG) process in the presence of AgAu alloy NPs with block copolymer shells as templates. The photocatalytic activities of the AgAu-TiO2 NPs on the photodecomposition of methylene blue (MB) are investigated. The AgAu-TiO2 composite NPs coated with 5.0% titania related to block copolymers show higher photocatalytic activity than the other samples in which the titania contents are larger than 5.0%. The results indicate that the increase of the thickness of the TiO2 shell leads to the decrease of the photocatalytic activity.

  2. Electroless Deposition of W-doped Ag Dendrites from HF Solution

    Institute of Scientific and Technical Information of China (English)

    YE Wei-Chun; MA Chuan-Li; CHANG Yan-Long; WANG Chun-Ming

    2008-01-01

    A simple method was developed for the preparation of W-doped Ag dendrites by using electroless deposition from hydrofluoride solution. The samples characterized by XPS, XRD, SEM and TEM techniques, show that the growth of silver is leading and can not be changed essentially by tungstate ions in the Ag-W binary system. A doping mode of W element was proposed, i.e., the doping of W may occur during silver deposition through chemi-sorption-chemical bonding of oxygen atoms of tungstate dimer with silver. Cyclic voltammetry was employed to determine the chemical bonding energy between silver and oxygen.

  3. 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.

  4. 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.

  5. Lattice location of implanted Ag in Si

    CERN Document Server

    Wahl, U; Vantomme, A

    2002-01-01

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

  6. Ti{sub 1−x}Ag{sub x} electrodes deposited on polymer based sensors

    Energy Technology Data Exchange (ETDEWEB)

    Marques, S.M., E-mail: mariana.marques@fisica.uminho.pt [GRF-CFUM, Physics Department, University of Minho, 4800-058 Guimarães (Portugal); Manninen, N.K. [SEG-CEMUC Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); Ferdov, Stanislav [GRF-CFUM, Physics Department, University of Minho, 4800-058 Guimarães (Portugal); Lanceros-Mendez, S. [Physics Department, University of Minho, 4700-057 Braga (Portugal); Carvalho, S. [GRF-CFUM, Physics Department, University of Minho, 4800-058 Guimarães (Portugal); SEG-CEMUC Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal)

    2014-10-30

    Graphical abstract: - Highlights: • Ti{sub 1−x}Ag{sub x} thin films with diverse Ag/Ti ratios were deposited by sputtering on piezoelectric PVDF. • The deposition conditions do not promote changes on the polymer structure. • The coatings do not change the piezoelectric properties of the polymer. • Sheet resistivity values show a typical behavior of a binary alloy system. • The deposited films are suitable for the development of functional electrodes. - Abstract: Piezoelectric materials are interesting for the development of sensors and actuators for biomedical applications in areas such as smart prosthesis, implantable biosensors and biomechanical signal monitoring, among others. For acquiring or applying the electrical signal from/to the piezoelectric material, suitable electrodes can be produced from Ti based coatings with tailored multifunctional properties: conductivity and antibacterial characteristics through Ag inclusions. This work reports on Ti{sub 1−x}Ag{sub x} electrodes with different Ag/Ti atomic ratios deposited by dc and pulsed magnetron sputtering at room temperature on poly(vinylidene fluoride), PVDF. The X-ray diffraction (XRD) results revealed that the deposition conditions preserve the polymer structure and suggested the presence of crystalline Tiβ phase in pure titanium coating and fcc-Ag phase in pure silver coating. According to the results obtained from scanning electron microscopy (SEM) analysis, the coatings are homogeneous and no clusters were found; since β-PVDF is anisotropic, the deposited coatings replicate the underlying substrate surface. Sheet resistivity values show a typical behavior of a binary alloy system, with low resistivity values for coatings of zone 1 (Ti rich) and zone 3 (Ag rich) and a slightly higher resistivity values in zone 2. The piezoelectricity of the different samples show similar values.

  7. Reducing strength prevailing at root surface of plants promotes reduction of Ag+ and generation of Ag(0/Ag2O nanoparticles exogenously in aqueous phase.

    Directory of Open Access Journals (Sweden)

    Peddisetty Pardha-Saradhi

    Full Text Available Potential of root system of plants from wide range of families to effectively reduce membrane impermeable ferricyanide to ferrocyanide and blue coloured 2,6-dichlorophenol indophenol (DCPIP to colourless DCPIPH2 both under non-sterile and sterile conditions, revealed prevalence of immense reducing strength at root surface. As generation of silver nanoparticles (NPs from Ag+ involves reduction, present investigations were carried to evaluate if reducing strength prevailing at surface of root system can be exploited for reduction of Ag+ and exogenous generation of silver-NPs. Root system of intact plants of 16 species from 11 diverse families of angiosperms turned clear colorless AgNO3 solutions, turbid brown. Absorption spectra of these turbid brown solutions showed silver-NPs specific surface plasmon resonance peak. Transmission electron microscope coupled with energy dispersive X-ray confirmed the presence of distinct NPs in the range of 5-50 nm containing Ag. Selected area electron diffraction and powder X-ray diffraction patterns of the silver NPs showed Bragg reflections, characteristic of crystalline face-centered cubic structure of Ag(0 and cubic structure of Ag2O. Root system of intact plants raised under sterile conditions also generated Ag(0/Ag2O-NPs under strict sterile conditions in a manner similar to that recorded under non-sterile conditions. This revealed the inbuilt potential of root system to generate Ag(0/Ag2O-NPs independent of any microorganism. Roots of intact plants reduced triphenyltetrazolium to triphenylformazon and impermeable ferricyanide to ferrocyanide, suggesting involvement of plasma membrane bound dehydrogenases in reduction of Ag+ and formation of Ag(0/Ag2O-NPs. Root enzyme extract reduced triphenyltetrazolium to triphenylformazon and Ag+ to Ag(0 in presence of NADH, clearly establishing potential of dehydrogenases to reduce Ag+ to Ag(0, which generate Ag(0/Ag2O-NPs. Findings presented in this manuscript put

  8. Structural and superconducting properties of YBa2Cu3-xMxOy (M=Ag, Al

    Directory of Open Access Journals (Sweden)

    S Falahati

    2009-08-01

    Full Text Available   Samples of YBa2Cu3-xAgxOy with x=0, 0.1, 0.15, 0.2, 0.3 and samples of YBa2Cu3-xAlxOy with x=0, 0.01, 0.02, 0.03 and 0.045 are prepared by the sol-gel method. Structural and superconducting properties of samples are studied by electrical resistivity (R-T, X-ray diffraction (XRD and scanning electron microscopy (SEM. All the samples show transition to superconducting state and the transition temperatures of the samples increased with increasing Ag doping up to x=0.15. R-T measurements show a small decrease of TC (zero with increasing Al doping up to x=0.02, and followed by a faster decrease with increasing doping concentration. YBCO grains are better linked with increasing Ag doping. So, Ag has positive effects in superconducting properties of YBCO. The crystal structure of samples was refined by MAUD. These results show tha, Ag is substituted for Cu(1 in YBCO. According to these analysis, we introduce x=0.15 as the optimum value for doping concentration .

  9. Microwave-assisted solvothermal synthesis of flower-like Ag/AgBr/BiOBr microspheres and their high efficient photocatalytic degradation for p-nitrophenol

    International Nuclear Information System (INIS)

    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 ([C16mim]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 O2·−, Br0 and photogenerated h+ play key roles in the photocatalytic degradation process

  10. 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.

  11. 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.

  12. The Antimicrobial Properties of Silver Nanoparticles in Bacillus subtilis Are Mediated by Released Ag+ Ions.

    Directory of Open Access Journals (Sweden)

    Yi-Huang Hsueh

    Full Text Available The superior antimicrobial properties of silver nanoparticles (Ag NPs are well-documented, but the exact mechanisms underlying Ag-NP microbial toxicity remain the subject of intense debate. Here, we show that Ag-NP concentrations as low as 10 ppm exert significant toxicity against Bacillus subtilis, a beneficial bacterium ubiquitous in the soil. Growth arrest and chromosomal DNA degradation were observed, and flow cytometric quantification of propidium iodide (PI staining also revealed that Ag-NP concentrations of 25 ppm and above increased membrane permeability. RedoxSensor content analysis and Phag-GFP expression analysis further indicated that reductase activity and cytosolic protein expression decreased in B. subtilis cells treated with 10-50 ppm of Ag NPs. We conducted X-ray absorption near-edge structure (XANES and extended X-ray absorption fine structure (EXAFS analyses to directly clarify the valence and fine structure of Ag atoms in B. subtilis cells placed in contact with Ag NPs. The results confirmed the Ag species in Ag NP-treated B. subtilis cells as Ag2O, indicating that Ag-NP toxicity is likely mediated by released Ag+ ions from Ag NPs, which penetrate bacterial cells and are subsequently oxidized intracellularly to Ag2O. These findings provide conclusive evidence for the role of Ag+ ions in Ag-NP microbial toxicity, and suggest that the impact of inappropriately disposed Ag NPs to soil and water ecosystems may warrant further investigation.

  13. A binary functional substrate for enrichment and ultrasensitive SERS spectroscopic detection of folic acid using graphene oxide/Ag nanoparticle hybrids.

    Science.gov (United States)

    Ren, Wen; Fang, Youxing; Wang, Erkang

    2011-08-23

    Herein graphene oxide/Ag nanoparticle hybrids (GO/PDDA/AgNPs) were fabricated according to a self-assembly procedure. Using the obtained GO/PDDA/AgNPs as SERS substrates, an ultrasensitive and label-free detection of folic acid in water and serum was demonstrated based on the inherent SERS spectra of folic acid. The modified graphene oxide exhibited strong enrichment of folic acid due to the electrostatic interaction, and the self-assembled Ag nanoparticles greatly enhanced the SERS spectra of folic acid, both of which led to an ultrahigh sensitivity. Therefore, although the SERS enhancement of p-ATP on GO/PDDA/AgNPs was weaker than that on Ag nanoparticles, the SERS signals of folic acid on GO/PDDA/AgNPs were much stronger than that on Ag nanoparticles. To improve the detection, the concentration of GO/PDDA/AgNPs was optimized to reduce background of the graphene oxide. The SERS spectra of the folic acid showed that the minimum detected concentration of folic acid in water was as low as 9 nM with a linear response range from 9 to 180 nM. To estimate the feasibility of the detection method based on GO/PDDA/AgNPs for the practical applications, diluted serum containing different concentrations of folic acid was taken as real samples. It was established that the sensitivity and the linear range for the folic acid in serum were comparable to that in water. This ultrasensitive and label-free SERS detection of folic acid based on GO/PDDA/AgNPs offers great potential for practical applications of medicine and biotechnology.

  14. 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.

  15. Control of Ag nanoparticle distribution influencing bioactive and antibacterial properties of Ag-doped mesoporous bioactive glass particles prepared by spray pyrolysis.

    Science.gov (United States)

    Shih, Shao-Ju; Tzeng, Wei-Lung; Jatnika, Rifqi; Shih, Chi-Jen; Borisenko, Konstantin B

    2015-05-01

    Mesoporous bioactive glasses (MBGs) have become important bone implant materials because of their high specific surface area resulting in high bioactivity. Doping MBGs with Ag removes one of the remaining challenges to their applications, namely their lack of intrinsic antibacterial properties. In present work we demonstrate that Ag-doped MBGs can be prepared in one-step spray pyrolysis (SP) process. The SP preparation method offers the advantages of short processing times and continuous production over the sol-gel method previously used to prepare MBGs. Using scanning electron microscopy, transmission electron microscopy, and selected area electron diffraction we demonstrate that the synthesized MBG particles have amorphous structure with nanocrystalline Ag inclusions. The scanning transmission electron microscopy-X-ray energy dispersive spectrometry of cross-sectional samples shows that the distribution of the Ag dopant nanoparticles within MBGs can be controlled by using the appropriate formulation of the precursors. The distribution of the Ag dopant nanoparticles within the MBG particles was found to affect their surface areas, bioactivities and antibacterial properties. Based on the observations, we propose a mechanism describing MBG particle formation and controlling dopant distribution. PMID:25171327

  16. Facile synthesis of ternary Ag/AgBr-Ag2CO3 hybrids with enhanced photocatalytic removal of elemental mercury driven by visible light.

    Science.gov (United States)

    Zhang, Anchao; Zhang, Lixiang; Lu, Hao; Chen, Guoyan; Liu, Zhichao; Xiang, Jun; Sun, Lushi

    2016-08-15

    A novel technique for photocatalytic removal of elemental mercury (Hg(0)) using visible-light-driven Ag/AgBr-Ag2CO3 hybrids was proposed. The ternary Ag/AgBr-Ag2CO3 hybrids were synthesized by a simple modified co-precipitation method and characterized by N2 adsorption-desorption, scanning electron microscope (SEM), X-ray diffraction (XRD), UV-vis diffused reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) techniques. The effects of AgBr content, fluorescent lamp (FSL) irradiation, solution temperature, SO2 and NO on Hg(0) removal were investigated in detail. Furthermore, a possible reaction mechanism for higher Hg(0) removal was proposed, and the simultaneous removal of Hg(0), SO2 and NO was studied. The results showed that a high efficiency of Hg(0) removal was obtained by using Ag/AgBr-Ag2CO3 hybrids under fluorescent lamp irradiation. The AgBr content, FSL irradiation, solution temperature, and SO2 all exhibited significant effects on Hg(0) removal, while NO had slight effect on Hg(0) removal. The addition of Ca(OH)2 demonstrated a little impact on Hg(0) removal and could significantly improve the SO2-resistance performance of Ag/AgBr(0.7)-Ag2CO3 hybrid. The characterization results exhibited that hydroxyl radical (OH), superoxide radical (O2(-)), hole (h(+)), and Br(0), were reactive species responsible for removing Hg(0), and the h(+) played a key role in Hg(0) removal. PMID:27135702

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-01-01

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

  18. AGS experiments: 1993 - 1994 - 1995

    International Nuclear Information System (INIS)

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

  19. 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.

  20. The AGS CNI polarimeter

    International Nuclear Information System (INIS)

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

  1. [From JSLH (The Japanese Society for Laboratory Hematology): An Active Team Approach to Medicine as Laboratory Technologists, through Showing Bone Marrow and Peripheral Blood Samples Directly to Patients with Hematological Malignancy].

    Science.gov (United States)

    Shimizu, Sanae; Kojima, Yukari; Saito, Kyoko; Wada, Hisako; Yamamoto, Masahiro; Morinaga, Koji; Kawai, Yasukazu; Haba, Toshihiro

    2014-11-01

    The clinical path for the treatment of acute myeloid leukemia (AML) patients has been in practice in our hospital since 2003. In the clinical path, laboratory technologists take on the role of explaining the microscopic findings in bone marrow and peripheral blood samples to patients (with or without their families) using the view-sharing microscope in our laboratory. From July 2003 to October 2014, 56 patients were enrolled in the AML clinical path and given an explanation of their bone marrow and peripheral blood samples. The patients' median age was 62, and the median time spent for explanation was 40 minutes. We conducted a questionnaire feedback survey involving those who enrolled, and the results showed significant improvement in the recognition of the disease pathophysiology, treatment efficacy, and the importance of precautions against infectious diseases. Based on the feedback, we have made marked efforts to provide patients with an improved environment during the explanatory session. This includes installing a special display for the patients, drawing a schematic illustration that shows how the blood cells differentiate, and putting them into operation in a hematology ward to promote patient privacy and precautions against infectious diseases. Hematological laboratory technologists have played an important role in patient care in our hospital. To perform their role as effectively as possible, hematological laboratory technologists participate in the conferences of the Department of Hematology and Oncology regularly, in which medical staff members can discuss the conditions and clinical courses of patients. We aim to contribute to patient satisfaction by sophisticating specialized knowledge as hematological laboratory technologists and cooperate with other medical staff members.

  2. Microstructure, mechanical properties, bio-corrosion properties and antibacterial properties of Ti-Ag sintered alloys.

    Science.gov (United States)

    Chen, Mian; Zhang, Erlin; Zhang, Lan

    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 Ti2Ag 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 3wt.% in order to obtain a strong and stable antibacterial activity against Staphylococcus aureus bacteria. The bacterial mechanism was thought to be related to the Ti2Ag and its distribution.

  3. Microstructure, mechanical properties, bio-corrosion properties and antibacterial properties of Ti-Ag sintered alloys.

    Science.gov (United States)

    Chen, Mian; Zhang, Erlin; Zhang, Lan

    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 Ti2Ag 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 3wt.% in order to obtain a strong and stable antibacterial activity against Staphylococcus aureus bacteria. The bacterial mechanism was thought to be related to the Ti2Ag and its distribution. PMID:26952433

  4. Speciation analysis of 129I in seawater by carrier-free AgI-AgCl coprecipitation and accelerator mass spectrometric measurement

    DEFF Research Database (Denmark)

    Luo, Maoyi; Hou, Xiaolin; He, Chaohui;

    2013-01-01

    A rapid and simple method was developed for speciation analysis of 129I in seawater by selective coprecipitation of carrier-free iodide and accelerator mass spectrometry (AMS) measurement of 129I. Iodide was separated from seawater and other species of iodine by coprecipitation of AgI with Ag2SO3...... is higher than 70%. Six seawater samples collected from the Norwegian Sea were analyzed by this method as well as a conventional anion-exchange chromatographic method; the results from the two methods show no significant difference (p = 0.05). Because only one separation step and fewer chemicals...... are involved in the procedure, this method is suitable for operation on board sampling vessels, as it avoids the transport of samples to the laboratory and storage for a longer time before analysis, therefore significantly improving the analytical capacity and reliability of speciation analysis of 129I...

  5. Synthesis and thermoluminescent characterization of LiF doped with Ag; Sintesis y caracterizacion termoluminiscente de LiF dopado con Ag

    Energy Technology Data Exchange (ETDEWEB)

    Encarnacion, E. K.; Reyes, J.; Guerrero, Z. [Universidad Autonoma de Santo Domingo, Facultad de Ciencias, Ciudad Universitaria, Santo Domingo (Dominican Republic); Sosa, M. A.; Vallejo, M. A.; Rivera P, E., E-mail: emma.kee@gmail.com [Universidad de Guanajuato, Campus Leon, Division de Ciencias e Ingenierias, Loma del Bosque 103, Col. Lomas del Campestre, 37150 Leon, Guanajuato (Mexico)

    2015-10-15

    Full text: In this paper the synthesis and characterization of lithium fluoride (LiF) crystals pure and activated with silver (Ag) is reported. The synthesis was carried out by the method of co-precipitation; three samples were obtained one of pure LiF and two were activated with 0.02 and 0.04% of Ag. All samples were subjected to X-ray emission and the results were analyzed. The synthesized samples were characterized by X-ray diffraction, thermoluminescence and X-ray fluorescence. The XRD results show complete crystal structures. The radiation dosimetry responses are discussed. These are the first results of a research conducted at the Universidad Autonoma de Santo Domingo in collaboration with the Universidad de Guanajuato. (Author)

  6. Soldering of Bi-2223/Ag high temperature superconducting tapes with Sn-Pb-Bi-Ag alloy paste

    Science.gov (United States)

    Wei, Guo; Guisheng, Zou; Aiping, Wu; Hailin, Bai; Jialie, Ren

    2010-01-01

    Soldered joints of Bi-2223/Ag-sheathed high temperature superconducting multifilamentary tapes were fabricated using 63 wt.%Sn-34 wt.%Pb-1 wt.%Bi-2 wt.%Ag paste. The soldered joints were observed by scanning electron microscope (SEM) and X-ray diffraction (XRD). Moreover, the electrical properties of joints were evaluated by current-voltage curves, and the tensile strengths of the joints were also tested. The results show that the soldered joint consists of Ag sheath - Ag 3Sn compound layer - PbSn 2 and Ag 3Sn solder layer - Ag 3Sn compound layer - Ag sheath. The joints are obeyed with Ohms Law and the magnitude of the joint resistance, which deceases with the increase of the overlap length, can reach the order of 10 -8 Ω. The tensile strength of the joints with a brittle fracture mode is a little lower than that of the original tapes.

  7. Ag(+)-mediated assembly of 5'-guanosine monophosphate.

    Science.gov (United States)

    Loo, Kristine; Degtyareva, Natalya; Park, Jihae; Sengupta, Bidisha; Reddish, Michaeal; Rogers, Christopher C; Bryant, Andrea; Petty, Jeffrey T

    2010-04-01

    Polymorphic forms of nucleic acids provide platforms for new nanomaterials, and transition metal cations give access to alternative arrangements of nucleobases by coordinating with electron-rich functional groups. Interaction of Ag(+) with 5'-guanosine monophosphate (5'-GMP) is considered in this work. Ag(+) promotes nucleotide stacking and aggregation, as indicated by the increased viscosity of 5'-GMP solutions with Ag(+), magnification of the circular dichroism response of guanine by Ag(+), and exothermic reactions between Ag(+) and guanine derivatives. Isothermal titration calorimetry studies show that the reaction is favored starting at 10 microM 5'-GMP. Utilizing the exothermic heat change associated with reaction of Ag(+) with 5'-GMP, local structure within the aggregate was assessed. On the basis of the salt dependence of the reaction and comparison with the corresponding nucleoside, the dianionic phosphate of 5'-GMP is one binding site for Ag(+), although this electrostatic interaction is not a dominant contribution to the overall heat change. Another binding site is the N7 on the nucleobase, as determined via studies with 7-deazaguanosine. Besides this binding site, Ag(+) also associates with the O6, as earlier studies deduced from the shift in the carbonyl stretching frequency associated with adduct formation. With these two binding sites on the nucleobase, the empirical stoichiometry of approximately 1 Ag(+):nucleobase derived from the calorimetry studies indicates that Ag(+) coordinates two nucleobases. The proposed structural model is a Ag(+)-mediated guanine dimer within a base stacked aggregate. PMID:20205377

  8. 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.

  9. 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.

  10. 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.

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

    Science.gov (United States)

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

    2016-03-14

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

  12. 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.

  13. High-Quality AgGaTe2 Layers on Si Substrates with Ag2Te Buffer Layers

    Science.gov (United States)

    Uruno, Aya; Kobayashi, Masakazu

    2016-09-01

    AgGaTe2 layers were successfully grown on Si substrates by the close-spaced sublimation method. The Si substrates were confirmed to be etched during AgGaTe2 layer growth when the layer was grown directly on the substrate. To eliminate melt-back etching, a buffer layer of Ag2Te was introduced. It was found that the Ag2Te buffer layer changed into the AgGaTe2 layer during the growth process, and a uniform AgGaTe2 layer with an abrupt interface was formed. Both the diffusion of Ga into Ag2Te and the growth of AgGaTe2 occurred simultaneously. It was confirmed that uniform AgGaTe2 layers could be formed without any traces of the Ag2Te layer or melt-back etching by tuning the growth parameters. A solar cell was also fabricated using the p-AgGaTe2/n-Si heterojunction. This solar cell showed conversion efficiency of approximately 3%.

  14. Evaluation of cysticercus-specific IgG (total and subclasses and IgE antibody responses in cerebrospinal fluid samples from patients with neurocysticercosis showing intrathecal production of specific IgG antibodies

    Directory of Open Access Journals (Sweden)

    Lisandra Akemi Suzuki

    2013-02-01

    Full Text Available In the present study, an enzyme-linked immunosorbent assay (ELISA standardized with vesicular fluid of Taenia solium cysticerci was used to screen for IgG (total and subclasses and IgE antibodies in cerebrospinal fluid (CSF samples from patients with neurocysticercosis showing intrathecal production of specific IgG antibodies and patients with other neurological disorders. The following results were obtained: IgG-ELISA: 100% sensitivity (median of the ELISA absorbances (MEA=1.17 and 100% specificity; IgG1-ELISA: 72.7% sensitivity (MEA=0.49 and 100% specificity; IgG2-ELISA: 81.8% sensitivity (MEA=0.46 and 100% specificity; IgG3-ELISA: 63.6% sensitivity (MEA=0.12 and 100% specificity; IgG4-ELISA: 90.9% sensitivity (MEA=0.85 and 100% specificity; IgE-ELISA 93.8% sensitivity (MEA=0.60 and 100% specificity. There were no significant differences between the sensitivities and specificities in the detection of IgG-ELISA and IgE-ELISA, although in CSF samples from patients with neurocysticercosis the MEA of the IgG-ELISA was significantly higher than that of the IgE-ELISA. The sensitivity and MEA values of the IgG4-ELISA were higher than the corresponding values for the other IgG subclasses. Future studies should address the contribution of IgG4 and IgE antibodies to the physiopathology of neurocysticercosis.

  15. The effect of AgNO3 concentration on formation of Ag nanoparticles in Sol-Gel derived Ag-SiO2 thin films

    Directory of Open Access Journals (Sweden)

    A Babapour

    2007-12-01

    Full Text Available   In this investigation, Ag-SiO2 thin films with different concentrations of Ag (0.2, 0.4, 1.6 and 8% has been fabricated on soda-lime glass substrate using sol-gel method. After an annealing process, physical and chemical properties of the deposited silica films containing Ag nanoparticles have been studied including optical, topographical structural, morphological and size of the nanoparticle as well as their distribution using UV-visble spectrophotometery, atomic force microscopy (AFM, scanning electron microscopy (SEM, and transmission electron microscopy (TEM techniques, respectively. Based on our data analysis, the Ag nanoparticles did not form in the samples with low (0.2% and high Ag concentrations (8%, without any suitable annealing process. Instead, the nanoparticles were formed easily for the intermediate Ag concentrations. In fact, for the the low and high Ag concentration, the Ag nanoparticles formed at the annealing temperature of 200 º C. In addition, according to TEM observations, the minimum average size of the synthesized particles were determined about 4 hm for the thin films containing 0.2% Ag concentration.

  16. Surface-enhanced Raman scattering detection of silver nanoparticles in environmental and biological samples.

    Science.gov (United States)

    Guo, Huiyuan; Xing, Baoshan; Hamlet, Leigh C; Chica, Andrea; He, Lili

    2016-06-01

    Growing concerns over the potential release and threat of silver nanoparticles (AgNPs) to environmental and biological systems urge researchers to investigate their fate and behavior. However, current analytical techniques cannot meet the requirements for rapidly, sensitively and reliably probing AgNPs in complex matrices. Surface-enhanced Raman spectroscopy (SERS) has shown great capability for rapid detection of AgNPs based on an indicator molecule that can bind on the AgNP surface. The objective of this study was to exploit SERS to detect AgNPs in environmental and biological samples through optimizing the Raman indicator for SERS. Seven indicator molecules were selected and determined to obtain their SERS signals at optimal concentrations. Among them, 1,2-di(4-pyridyl)ethylene (BPE), crystal violet and ferric dimethyl-dithiocarbamate (ferbam) produced the highest SERS intensities. Further experiments on binding competition between each two of the three candidates showed that ferbam had the highest AgNPs-binding ability. The underlying mechanism lies in the strong binding affinity of ferbam with AgNPs via multiple sulfur atoms. We further validated ferbam to be an effective indicator for SERS detection of as low as 0.1mg/L AgNPs in genuine surface water and 0.57 mg/L in spinach juice. Moreover, limited interference on SERS detection of AgNPs was found from environmentally relevant inorganic ions, organic matter, inorganic particles, as well as biologically relevant components, demonstrating the ferbam-assisted SERS is an effective and sensitive method to detect AgNPs in complex environmental and biological samples. PMID:26956173

  17. Surface-enhanced Raman scattering detection of silver nanoparticles in environmental and biological samples.

    Science.gov (United States)

    Guo, Huiyuan; Xing, Baoshan; Hamlet, Leigh C; Chica, Andrea; He, Lili

    2016-06-01

    Growing concerns over the potential release and threat of silver nanoparticles (AgNPs) to environmental and biological systems urge researchers to investigate their fate and behavior. However, current analytical techniques cannot meet the requirements for rapidly, sensitively and reliably probing AgNPs in complex matrices. Surface-enhanced Raman spectroscopy (SERS) has shown great capability for rapid detection of AgNPs based on an indicator molecule that can bind on the AgNP surface. The objective of this study was to exploit SERS to detect AgNPs in environmental and biological samples through optimizing the Raman indicator for SERS. Seven indicator molecules were selected and determined to obtain their SERS signals at optimal concentrations. Among them, 1,2-di(4-pyridyl)ethylene (BPE), crystal violet and ferric dimethyl-dithiocarbamate (ferbam) produced the highest SERS intensities. Further experiments on binding competition between each two of the three candidates showed that ferbam had the highest AgNPs-binding ability. The underlying mechanism lies in the strong binding affinity of ferbam with AgNPs via multiple sulfur atoms. We further validated ferbam to be an effective indicator for SERS detection of as low as 0.1mg/L AgNPs in genuine surface water and 0.57 mg/L in spinach juice. Moreover, limited interference on SERS detection of AgNPs was found from environmentally relevant inorganic ions, organic matter, inorganic particles, as well as biologically relevant components, demonstrating the ferbam-assisted SERS is an effective and sensitive method to detect AgNPs in complex environmental and biological samples.

  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. Toluene removal by sequential adsorption-plasma catalytic process: Effects of Ag and Mn impregnation sequence on Ag-Mn/γ-Al2O3.

    Science.gov (United States)

    Qin, Caihong; Huang, Xuemin; Dang, Xiaoqing; Huang, Jiayu; Teng, Jingjing; Kang, Zhongli

    2016-11-01

    A series of Ag-Mn/γ-Al2O3 were prepared under different Ag/Mn impregnation sequence and tested in the sequential adsorption-plasma catalytic removal of toluene. When Mn was impregnated first, the resulting catalyst, Ag-Mn(F)/γ-Al2O3, had longer breakthrough time, gave less emission of toluene, had higher CO2 selectivity, and had better carbon balance and COx yield compared to catalysts prepared via other impregnation sequences. After 120 min of NTP treatment, the carbon balance of Ag-Mn(F)/γ-Al2O3 was 91%, with 87% as COx contributions. A Brunauer-Emmett-Teller (BET) analysis and X-ray photoelectron spectroscopy (XPS) results show that, the impregnation sequence impacts the BET surface area and the ratio and existing state of Ag on the surface of the catalysts. The longer breakthrough time when using Ag-Mn(F)/γ-Al2O3 as catalyst is attributed to the large amount of Ag(+) on the surface. Ag(+) is a new active site for toluene adsorption. When Ag was impregnated first (Ag(F)-Mn/γ-Al2O3) or Ag and Mn co-impregnated (Ag-Mn-C/γ-Al2O3), the predominant specie was Ag(+). Both Ag(0) and Ag(+) species were detected on Ag-Mn(F)/γ-Al2O3. Ag(0) cooperation with MnOx may promote the migration of surface active oxygen. This would facilitate the oxidation of adsorbed toluene with CC bond already weakened by Ag(+) and would result in higher CO2 selectivity and better carbon balance as seen in the Ag-Mn(F)/γ-Al2O3 system. PMID:27494312

  20. 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.

  1. Core-shell AgSiO2-protoporphyrin IX nanoparticle: Effect of the Ag core on reactive oxygen species generation

    Science.gov (United States)

    Lismont, M.; Pá; ez-Martinez, C.; Dreesen, L.

    2015-03-01

    Photodynamic therapy (PDT) for cancer is based on the use of a light sensitive molecule to produce, under specific irradiation, toxic reactive oxygen species (ROS). A way to improve the therapy efficiency is to increase the amount of produced ROS near cancer cells. This aim can be achieved by using a metal enhanced process arising when an optically active molecule is located near a metallic nanoparticle (NP). Here, the coupling effect between silver (Ag) NPs and protoporphyrin IX (PpIX) molecules, a clinically approved photosensitizer, is studied compared first, to PpIX fluorescence yield and second, to ROS production efficiency. By applying a modified Stöber process, PpIX was encapsulated into a silica (SiO2) shell, surrounding a 60 nm sized Ag core. We showed that, compared to SiO2-PpIX NPs, Ag coated SiO2-PpIX NPs dramatically decreased PpIX fluorescence together with singlet oxygen production efficiency. However, after incubation time in the dark, the amount of superoxide anions generated by the Ag doped sample was higher than the control sample one.

  2. Titanium dioxide encapsulation of supported Ag nanoparticles on the porous silica bead for increased photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hui, E-mail: liuhui@sust.edu.cn; Deng, Lu, E-mail: 734217000@qq.com; Sun, Chaochao, E-mail: 596527138@qq.com; Li, Junqi, E-mail: 846119802@qq.com; Zhu, Zhenfeng, E-mail: 329317644@qq.com

    2015-01-30

    Graphical abstract: - Highlights: • A novel Ag-loading and TiO{sub 2}-coating technique was used to prepare samples. • The photocatalytic activity of the product was evaluated by removing of Rh B. • The as-synthesized samples showed an excellent photocatalytic activity. - Abstract: A new synthetic strategy has been developed to encapsulate Ag nanoparticles in heterogeneous catalysts to prevent their dropping and sintering. Ag nanoparticles with diameters about 5–10 nm were first supported on the porous silica bead. These were then covered with a fresh layer of titanium dioxide with the thickness about 5 nm. SEM and TEM images were used to confirm the success of each synthesis step, and the photocatalytic activity of the as-synthesized samples was evaluated by photocatalytic decolorization of Rhodamine B (Rh B) aqueous solution at ambient temperature under both UV and visible light irradiation. The resulting titanium dioxide encapsulated Ag nanoparticles exhibited an enhanced photocatalytic activity under both UV and visible light irradiation, this can be attributed to effective charge separation and light harvesting of the plasmonic silver nanoparticles decoration, even the reducing of the exciton recombination rate caused by the small grain size of anatase TiO{sub 2} nanocrystals.

  3. Fabrication of worm-like Ag2S nanocrystals under mediation of protein

    Indian Academy of Sciences (India)

    Dezhi Qin; Li Zhang; Xian Du; Guangrui Yang; Qiuxia Zhang

    2015-10-01

    A simple protein-assisted method was reported to synthesize pepsin-conjugated Ag2S nanocrystals in aqueous solution. The morphology, composition and structure of the products were characterized by transmission electron microscopy, high-resolution transmission electron microscopy, energy-dispersive spectroscopy, selected area electron diffraction and X-ray diffraction measurements. The results showed that as-prepared monoclinic Ag2S nanocrystals are worm-like nanochains in shape with sizes about 25 nm in diameter and up to hundreds of nanometres in length. The multiple coordinate bonds of pepsin molecules to the surface of Ag2S nanocrystals make as-prepared samples have good colloidal stability and biocompatibility as elucidated by Fourier transform infrared examination. Thermogravimetry–differential scanning calorimetry analysis indicated that the obtained products are inorganic–organic nanocomposites and there is strong interaction between Ag2S and pepsin. This interaction could result in the change of hydrophilic environment of pepsin and consequently intrinsic fluorescence of protein was quenched by Ag2S nanocrystals. Furthermore, the nanochains assembly of particle–particle and rod–rod oriented attachment was discussed to investigate the growth mechanism.

  4. Preparation and antibacterial activity of Fe{sub 3}O{sub 4}-Ag nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Gong Ping [State Key Laboratory of Chemo/Biosensing and Chemometrics, Biomedical Engineering Centre, College of Chemistry and Chemical Engineering, Hunan University, Research Centre for Bio-Nanotechnology Engineering of Hunan Province, Changsha 410082 (China); Li Huimin [Biomedical Engineering Center, College of Material Science and Technology, Hunan University, Changsha, 410082 (China); He Xiaoxiao [State Key Laboratory of Chemo/Biosensing and Chemometrics, Biomedical Engineering Centre, College of Chemistry and Chemical Engineering, Hunan University, Research Centre for Bio-Nanotechnology Engineering of Hunan Province, Changsha 410082 (China)] (and others)

    2007-07-18

    Bifunctional Fe{sub 3}O{sub 4}-Ag nanoparticles with both superparamagnetic and antibacterial properties were prepared by reducing silver nitrate on the surface of Fe{sub 3}O{sub 4} nanoparticles using the water-in-oil microemulsion method. Formation of well-dispersed nanoparticles with sizes of 60 {+-} 20 nm was confirmed by transmission electron microscopy and dynamic light scattering. X-ray diffraction patterns and UV-visible spectroscopy indicated that both Fe{sub 3}O{sub 4} and silver are present in the same particle. The superparamagnetism of Fe{sub 3}O{sub 4}-Ag nanoparticles was confirmed with a vibrating sample magnetometer. Their antibacterial activity was evaluated by means of minimum inhibitory concentration value, flow cytometry, and antibacterial rate assays. The results showed that Fe{sub 3}O{sub 4}-Ag nanoparticles presented good antibacterial performance against Escherichia coli (gram-negative bacteria), Staphylococcus epidermidis (gram-positive bacteria) and Bacillus subtilis (spore bacteria). Furthermore, Fe{sub 3}O{sub 4}-Ag nanoparticles can be easily removed from water by using a magnetic field to avoid contamination of surroundings. Reclaimed Fe{sub 3}O{sub 4}-Ag nanoparticles can still have antibacterial capability and can be reused.

  5. Electrical and photoconductivity studies on AgSbSe2 thin films

    Science.gov (United States)

    Namitha Asokan, T.; Urmila, K. S.; Pradeep, B.

    2015-02-01

    Silver antimony selenide thin films have been deposited on ultrasonically cleaned glass substrate at a vacuum of 10-5 torr using reactive evaporation technique. The preparative parameters like substrate temperature and incident fluxes have been properly controlled in order to get highly reproducible compound films. The polycrystalline nature of the sample is confirmed using XRD. The dependence of the electrical conductivity on the temperature has also been studied. The prepared AgSbSe2 samples show p-type conductivity. The samples show a little photoresponse.

  6. Synthesis of biocompatible AuAgS/Ag2S nanoclusters and their applications in photocatalysis and mercury detection

    International Nuclear Information System (INIS)

    In this paper, a facile approach for preparation of AuAgS/Ag2S nanoclusters was developed. The unique AuAgS/Ag2S nanoclusters capped with biomolecules exhibit interesting excellent optical and catalytic properties. The fluorescent AuAgS/Ag2S nanoclusters show tunable luminescence depending on the nanocluster size. The apoptosis assay demonstrated that the AuAgS/Ag2S nanoclusters showed low cytotoxicity and good biocompatibility. Therefore, the nanoclusters can be used not only as a probe for labeling cells but also for their photocatalytic activity for photodegradation of organic dye. Moreover, a highly selective and sensitive assay for detection of mercury including Hg2+ and undissociated mercury complexes was developed based on the quenching fluorescent AuAgS/Ag2S nanoclusters, which provides a promising approach for determining various forms of Hg in the mercury-based compounds in environment. These unique nanoclusters may have potential applications in biological labeling, sensing mercury, and photodegradation of various organic pollutants in waste water.Graphical Abstract

  7. Synthesis of biocompatible AuAgS/Ag{sub 2}S nanoclusters and their applications in photocatalysis and mercury detection

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Qian; Chen, Shenna; Zhang, Lingyang; Huang, Haowen, E-mail: hhwn09@163.com; Liu, Fengping [Hunan University of Science and Technology, Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Hunan Provincial University Key Laboratory of QSAR/QSPR, School of Chemistry and Chemical Engineering (China); Liu, Xuanyong, E-mail: xyliu@mail.sic.ac.cn [Chinese Academy of Sciences, State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics (China)

    2014-12-15

    In this paper, a facile approach for preparation of AuAgS/Ag{sub 2}S nanoclusters was developed. The unique AuAgS/Ag{sub 2}S nanoclusters capped with biomolecules exhibit interesting excellent optical and catalytic properties. The fluorescent AuAgS/Ag{sub 2}S nanoclusters show tunable luminescence depending on the nanocluster size. The apoptosis assay demonstrated that the AuAgS/Ag{sub 2}S nanoclusters showed low cytotoxicity and good biocompatibility. Therefore, the nanoclusters can be used not only as a probe for labeling cells but also for their photocatalytic activity for photodegradation of organic dye. Moreover, a highly selective and sensitive assay for detection of mercury including Hg{sup 2+} and undissociated mercury complexes was developed based on the quenching fluorescent AuAgS/Ag{sub 2}S nanoclusters, which provides a promising approach for determining various forms of Hg in the mercury-based compounds in environment. These unique nanoclusters may have potential applications in biological labeling, sensing mercury, and photodegradation of various organic pollutants in waste water.Graphical Abstract.

  8. Enhanced ultraviolet photocatalytic activity of Ag/ZnO nanoparticles synthesized by modified polymer-network gel method

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Y. H.; Xu, M., E-mail: hsuming-2001@aliyun.com [Southwest University for Nationalities, Key Laboratory of Information Materials of Sichuan Province, School of Electrical and Information Engineering (China); Xu, L. X. [Nanyang Technological University, Plasma Sources and Applications Center, NIE (Singapore); Zhang, C. L.; Zhang, Q. P.; Xu, X. N. [Southwest University for Nationalities, Key Laboratory of Information Materials of Sichuan Province, School of Electrical and Information Engineering (China); Xu, S. [Nanyang Technological University, Plasma Sources and Applications Center, NIE (Singapore); Ostrikov, K., E-mail: kostya.ostrikov@qut.edu.au [Queensland University of Technology, Institute for Future Environments and School of Chemistry, Physics, and Mechanical Engineering (Australia)

    2015-09-15

    Ag/ZnO nanoparticle (NP) heterostructures are synthesized through a modified polymer-network gel method in which glucose is added to the precursor solution to prevent the gel from drastically shrinking during drying of the aqueous solution. Structural and optical properties of the samples are characterized by a range of techniques including XRD, SEM, TEM, XPS, UV–Vis, and PL. The high-quality Ag-ZnO heterostructure is evidenced clearly by high-resolution TEM. The Ag/ZnO heterostructure nanocomposites exhibit a higher photocatalytic activity in the degradation of methyl orange than pure ZnO. Especially, Ag/ZnO NP heterostructures with the Ag/Zn molar ratio of 5:95 (sample ZA-5) show the highest degradation efficiency, which is 11 times higher compared with pure ZnO. The photoluminescence properties of the heterostructures and O defect states are studied to well explain the observed photocatalytic effects. ZA-5 also exhibits competitive photocatalytic activity for the degradation of other pollutant dyes such as Methylene blue and Rhodamine B compared with the recently reported techniques, while showing excellent catalyst photostability as well as offering simplicity and reliability.

  9. Synergistic bactericidal effect by combined exposure to Ag nanoparticles and UVA

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xiaoxu; Toyooka, Tatsushi; Ibuki, Yuko, E-mail: ibuki@u-shizuoka-ken.ac.jp

    2013-08-01

    Broad and strong antimicrobial properties of silver (Ag) have been used for biomedical applications, water treatment, etc. In this study, a synergistic antibacterial effect between Ag nanoparticles (AgNPs) and ultraviolet (UV) light was examined. AgNPs (< 0.1 μm) with subsequent exposure to UVA (320–400 nm) showed pronounced toxicity in Escherichia coli, but micro-sized Ag particles (> 1 μm) with UVA and AgNPs with UVB (280–325 nm) did not. As significant bactericidal activity was also exhibited by hydrogen peroxide-treated AgNPs, the surface oxidation of AgNPs caused by UVA irradiation was considered to contribute to the enhanced antibacterial effect. Although no difference in NP-incorporation rates was observed with or without the surface oxidation of AgNPs, a particle size of less than 0.1 μm was a factor for AgNPs uptake and an essential requirement for the antimicrobial function of Ag particles. Incorporated AgNPs oxidized by UVA irradiation released larger amounts of Ag ion inside cells than reduced AgNPs, which reacted with intercellular molecules having –SH groups such as glutathione. The synergistic use of AgNPs and UVA could become a powerful tool with broad antimicrobial applications. Highlights: • Combined treatment with AgNPs and UV achieved a remarkable antibacterial effect in E. coli. • For the antibacterial effect, it is necessary to satisfy the following requirements: • 1) Translocation of nano-sized Ag particles inside E. coli. • 2) Oxidation of AgNPs by UVA, and extensive and persistent release of Ag{sup +} inside E. coli. • Ag{sup +} released inside cells reacted with intercellular molecules having –SH groups such as GSH.

  10. Modeling the AgInSbTe Memristor

    OpenAIRE

    Yu, J.; Li, Y.; X. Mu; J. Zhang; Miao, X.; Wang, S.

    2015-01-01

    The AgInSbTe memristor shows gradual resistance tuning characteristics, which makes it a potential candidate to emulate biological plastic synapses. The working mechanism of the device is complex, and both intrinsic charge-trapping mechanism and extrinsic electrochemical metallization effect are confirmed in the AgInSbTe memristor. Mathematical model of the AgInSbTe memristor has not been given before. We propose the flux-voltage controlled memristor model. With piecewise linear approximation...

  11. 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.

  12. Feasibility study of CaSO4:Eu, CaSO4:Eu,Ag and CaSO4:Eu,Ag(NP) as thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    This work evaluates the dosimetric properties of crystals of CaSO4 doped with unusual elements, such as europium (Eu) and silver (Ag), including their nanoparticle forms, after the incorporation of glass or Teflon and compares them with well-known thermoluminescent dosimeters (TLD). X-ray diffraction analyses showed that samples of doped CaSO4 exhibit only a single phase corresponding to the crystal structure of anhydrite. Optical spectroscopy confirmed the presence of Eu3+ in the crystal matrix and a luminescent gain due the presence of silver nanoparticles. The composites showed thermoluminescent emission glow curves, with a single peak centered at approximately 200 °C for pellets with Teflon and at 230 °C for pellets with glass. The dosimeters based on calcium sulfate doped with europium and silver nanoparticles provided the most intense thermoluminescent (TL) emission of the composites studied. In comparison with commercial TLD, such as LiF:Mg,Ti and CaSO4:Dy, the CaSO4:Eu,Ag(NP)+glass produced in this work presented similar low detection limits and higher sensitivity. The new methods for the preparation of dosimeters and the incorporation of glass are shown to be viable because all of the samples presented a linear, reproducible and first order kinetic TL emission. - Highlights: • Thermoluminescent properties of CaSO4 doped with Eu, Ag and Ag nanoparticles were evaluated. • Crystals were grown using a production route based in the Yamashita method. • Glass or Teflon was incorporate to the crystals in order to obtain composites. • The TL responses of the composites are proportional to the dose absorbed. • The CaSO4:Eu,Ag(NP) + glass has potential to be used as a thermoluminescent dosimeter

  13. An Echinococcus multilocularis Antigen B3 Proteoform That Shows Specific Antibody Responses to Active-Stage Alveolar Echinococcosis.

    Science.gov (United States)

    Ahn, Chun-Seob; Cai, Huixia; Kim, Jeong-Geun; Han, Xiumin; Ma, Xiao; Bae, Young-An; Yang, Hyun-Jong; Kang, Insug; Wang, Hu; Kong, Yoon

    2015-10-01

    Alveolar echinococcosis (AE), caused by the Echinococcus multilocularis metacestode, represents one of the most frequently fatal zoonoses. Early diagnosis significantly reduces morbidity and mortality associated with AE. Diagnosis of AE largely depends on a combination of imaging and serological tests due to its minimal clinical manifestations. Several antigens derived from the whole worm and protoscolex have been targeted for AE serodiagnosis, while the antigenic properties of E. multilocularis hydatid fluid (EmHF) are unclear. We observed two AE-specific 6- and 8-kDa antigen proteoforms through an immunoproteome array of the EmHF. We identified these proteins as representing an E. multilocularis antigen B3 (EmAgB3) isoform, and the proteins were shown to be encoded by the same gene. We cloned the gene and expressed the recombinant EmAgB3 protein (rEmAgB3) in Escherichia coli. rEmAgB3 exhibited sensitivity of 90.9% (80/88 cases) and specificity of 98.5% (597/606 samples) by immunoblotting. The positive and negative predictive values were 89.9% and 98.6%, respectively. The protein did not show antibody responses to 33 AE sera collected during posttreatment follow-up monitoring. Mouse sera experimentally infected with AE protoscoleces began to demonstrate specific antibody responses to native and recombinant EmAgB3 6 months after infection. At that stage, fully mature metacestode vesicles that harbored the brood capsule, primary cell, and protoscolex were observed within an AE mass(es). The response declined along with worm degeneration. Our results demonstrate that the immune responses to this EmAgB3 isoform were highly correlated with worm viability accompanied with AE progression. rEmAgB3 is a promising biomarker for serological assessment of AE patients. PMID:26269620

  14. Effects of Rapid Recurrent Thermal Annealing on Giant Magnetoresistance NiFe/Ag Multilayers

    Institute of Scientific and Technical Information of China (English)

    文岐业; 张怀武; 蒋向东; 唐晓莉; 张万里

    2003-01-01

    NiFe/Ag multilayers were prepared by dc sputtering onto glass-ceramic substrates directly at room temperature.The samples were thermally processed by rapid recurrent thermal anneal (RRTA). We studied the effects of RRTA on giant magnetoresistance (GMR) NiFe/Ag multilayer by controlling the anneal temperature as well as the rapid anneal cycle. The samples after three RRTA cycles have a similar annealing temperature dependence of GMR responses to the ordinary annealed samples. With the increasing anneal cycle, the GMR response improved at first and then reached an unexpected high value of 9% before descent rapidly. Microstructure study shows that this effect is ascribed to the transformation of continuous NiFe layer into discontinuous one, and then into a granular like film in a step-by-step way.

  15. Effect of Sugar Beet Variety and Nonhost Plant on Rhizoctonia solani AG2-2IIIB Soil Inoculum Potential Measured in Soil DNA Extracts.

    Science.gov (United States)

    Schulze, Sascha; Koch, Heinz-Josef; Märländer, Bernward; Varrelmann, Mark

    2016-09-01

    A direct soil DNA extraction method from soil samples (250 g) was applied for detection of the soilborne sugar-beet-infecting pathogen Rhizoctonia solani anastomosis group (AG) 2-2IIIB using a newly developed real-time polymerase chain reaction assay that showed specificity to AG2-2IIIB when tested against various R. solani AG. The assay showed a good relation between cycle threshold and amount of AG2-2IIIB sclerotia detected in three spiked field soils and was also able to detect the pathogen in naturally infested field soil samples. A field trial was conducted to quantify R. solani AG2-2IIIB soil inoculum potential (IP) before and after growing a susceptible and a resistant sugar beet variety as well as after subsequent growth of an expected nonhost winter rye. Plants of the susceptible sugar beet variety displayed a higher disease severity. A more than sixfold increase of the R. solani AG2-2IIIB soil IP was observed in contrast to the resistant variety that resulted in a constant IP. Growing winter rye significantly reduced soil IP to the initial level at sowing. Further research is required to better understand the interaction between disease occurrence and soil IP as well as the environmental influence on IP development. PMID:27143412

  16. 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.

  17. Synthesis and properties of the metallo-supramolecular polymer hydrogel poly[methyl vinyl ether-alt-mono-sodium maleate]·AgNO3: Ag+/Cu2+ ion exchange and effective antibacterial activity

    KAUST Repository

    Xu, Feng

    2014-01-01

    The commercial polymeric anhydride poly(methyl vinyl ether-alt-maleic anhydride) (PVM/MA) is converted by reaction with NaOH to give poly(methyl vinyl ether-alt-mono-sodium maleate) (PVM/Na-MA). By addition of AgNO 3-solution, the formation of the silver(i) supramolecular polymer hydrogel poly[methyl vinyl ether-alt-mono-sodium maleate]·AgNO 3 is reported. Freeze-dried samples of the hydrogel show a mesoporous network of polycarboxylate ligands that are crosslinked by silver(i) cations. In the intact hydrogel, ion-exchange studies are reported and it is shown that Ag+ ions can be exchanged by copper(ii) cations without disintegration of the hydrogel. The silver(i) hydrogel shows effective antibacterial activity and potential application as burn wound dressing. © the Partner Organisations 2014.

  18. Ag decorated 3D urchin-like TiO{sub 2} microstructures synthesized via a one-step solvothermal method and their photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peng; Peng, Chaohao; Yang, Mu, E-mail: yangmu@ustb.edu.cn

    2015-11-05

    Novel 3D urchin-like TiO{sub 2} microstructures decorated with Ag nanoparticles were successfully fabricated by one-step solvothermal method with the mixed solution of ethylene glycol, AgNO{sub 3} and tetrabutyl titanate. The morphology, microstructure, crystalline and composition of the composite materials could be adjusted through changing the content of AgNO{sub 3}, solvothermal temperature and time. The obtained samples were characterized by TEM, XRD and XPS. The formation mechanism of these microstructures was proposed. The Ag nanoparticle-decorated 3D urchin-like TiO{sub 2} microstructures showed excellent photocatalytic activity for the degradation of Rhodamine B under UV–Vis irradiation, which was attributed to their special 3D superstructure, crystalline composition and Ag nanoparticle decorated as well. - Graphical abstract: One-step solvothermal method synthesis of Ag decorated 3D urchin-like TiO{sub 2} microstructures with excellent photocatalytic activity. - Highlights: • A simple approach for Ag decorated 3D urchin-like TiO{sub 2} microstructures. • Simultaneously form, array, and decorate of TiO{sub 2} nanofibers. • Special morphology and composition for excellent photocatalytic activity.

  19. High activity of Ag-doped Cd0.1Zn0.9S photocatalyst prepared by the hydrothermal method for hydrogen production under visible-light irradiation

    Directory of Open Access Journals (Sweden)

    Leny Yuliati

    2014-05-01

    Full Text Available Background: The hydrothermal method was used as a new approach to prepare a series of Ag-doped Cd0.1Zn0.9S photocatalysts. The effect of Ag doping on the properties and photocatalytic activity of Cd0.1Zn0.9S was studied for the hydrogen production from water reduction under visible light irradiation.Results: Compared to the series prepared by the co-precipitation method, samples prepared by the hydrothermal method performed with a better photocatalytic activity. The sample with the optimum amount of Ag doping showed the highest hydrogen production rate of 3.91 mmol/h, which was 1.7 times higher than that of undoped Cd0.1Zn0.9S. With the Ag doping, a red shift in the optical response was observed, leading to a larger portion of the visible light absorption than that of without doping. In addition to the larger absorption in the visible-light region, the increase in photocatalytic activity of samples with Ag doping may also come from the Ag species facilitating electron–hole separation.Conclusion: This study demonstrated that Ag doping is a promising way to enhance the activity of Cd0.1Zn0.9S photocatalyst.

  20. CHEMICALLY MODIFIED FIELD-EFFECT TRANSISTORS - POTENTIOMETRIC AG+ SELECTIVITY OF PVC MEMBRANES BASED ON MACROCYCLIC THIOETHERS

    NARCIS (Netherlands)

    BRZOZKA, Z; COBBEN, PLHM; REINHOUDT, DN; EDEMA, JJH; KELLOGG, RM

    1993-01-01

    A chemically modified field-effect transistor (CHEMFET) with satisfactory Ag+ selectivity is described. The potentiometric Ag+ selectivities of CHEMFETs with plasticized PVC membranes based on macrocyclic thioethers have been determined. All the macrocyclic thioethers tested showed silver response a

  1. Photocatalytic activity of ZnO doped with Ag on the degradation of endocrine disrupting under UV irradiation and the investigation of its antibacterial activity

    Energy Technology Data Exchange (ETDEWEB)

    Bechambi, Olfa [Université de Tunis El Manar, Faculté des Sciences de Tunis, Laboratoire de Chimie des Matériaux et Catalyse, 2092, Tunis (Tunisia); Chalbi, Manel [Laboratoire de Bioprocédés Environnementaux, Centre de Biotechnologie de Sfax, B.P. 1177, 3018 Sfax (Tunisia); Najjar, Wahiba, E-mail: najjarwahiba2014@gmail.com [Université de Tunis El Manar, Faculté des Sciences de Tunis, Laboratoire de Chimie des Matériaux et Catalyse, 2092, Tunis (Tunisia); Sayadi, Sami [Laboratoire de Bioprocédés Environnementaux, Centre de Biotechnologie de Sfax, B.P. 1177, 3018 Sfax (Tunisia)

    2015-08-30

    Graphical abstract: - Highlights: • A series of Ag-doped ZnO were synthesized via hydrothermal method. • Effect of doping with silver on the textural, structural optical properties of ZnO. • The photocatalytic activity has been tested using bisphenol A and nonylphenol. • The highest degradation efficiency was obtained with 1% Ag. • Ag doping enhances the photocatalytic and antibacterial activities of ZnO. - Abstract: Ag-doped ZnO photocatalysts with different Ag molar content (0.0, 0.5, 1.0, 2.0 and 4.0%) were prepared via hydrothermal method. The X-ray diffraction (XRD), Nitrogen physisorption at 77 K, Fourier transformed infrared spectroscopy (FTIR), UV–-Visible spectroscopy, Photoluminescence spectra (PL) and Raman spectroscopy were used to characterize the structural, textural and optical properties of the samples. The results showed that Ag-doping does not change the average crystallite size with the Ag low content (≤1.0%) but slightly decreases with Ag high content (>1.0%). The specific surface area (S{sub BET}) increases with the increase of the Ag content. The band gap values of ZnO are decreased with the increase of the Ag doping level. The results of the photocatalytic degradation of bisphenol A (BPA) and nonylphenol (NP) in aqueous solutions under UV irradiation and in the presence of hydrogen peroxide (H{sub 2}O{sub 2}) showed that silver ions doping greatly improved the photocatalytic efficiency of ZnO. The TOC conversion BPA and NP are 72.1% and 81.08% respectively obtained using 1% Ag-doped ZnO. The enhancement of photocatalytic activity is ascribed to the fact that the modification of ZnO with an appropriate amount of Ag can increase the separation efficiency of the photogenerated electrons-holes in ZnO. The antibacterial activity of the catalysts which uses Escherichia coli as a model for Gram-negative bacteria confirmed that Ag-doped ZnO possessed more antibacterial activity than the pure ZnO.

  2. 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.

  3. Bulk eutectic Cu–Ag alloys with abundant twin boundaries

    International Nuclear Information System (INIS)

    Abundant growth twin boundaries are found and characterized in two bulk eutectic Cu–Ag alloys that can be obtained conveniently. The statistical electron backscattering diffraction results show that both hetero-twin and cube-on-cube orientation relationships coexist in the eutectic Cu–Ag alloy. The tensile strength of the eutectic alloy increases with a decrease in the layer thickness of the Cu/Ag phase. This study provides a potential way to produce bulk eutectic Cu–Ag alloy with abundant twin boundaries that offers a combination of high strength and high ductility.

  4. 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.

  5. The enhancement for SCR of NO by NH3 over the H2 or CO pretreated Ag/γ-Al2O3 catalyst.

    Science.gov (United States)

    Yu, Lemeng; Zhong, Qin; Zhang, Shule

    2014-06-28

    H2 or CO pretreatment had been processed on the Ag/γ-Al2O3 catalyst which significantly enhanced its NH3-SCR activity. The main purpose of this study was to prove that the impacts of pretreatment on silver species caused the enhancement. XRD, UV-vis, XPS, in situ FTIR and NO-TPD results showed the relationship between pretreatment, Ag species, NOX adsorption and NOX conversion. Extra nitrates were adsorbed on the Ag clusters which were produced by the pretreatment, thereby enhancing the activity. The reactivities between NO and NH3 had been studied. The difference between CO-pretreatment and H2-pretreatment had also been discussed. Furthermore, the durability and stability of the pretreated sample were tested. Therefore, a modified Ag2O/Al2O3 catalyst for NH3-SCR was researched.

  6. Synthesis and thermoelectric properties of Mn-doped AgSbTe2 compounds

    Institute of Scientific and Technical Information of China (English)

    Zhang He; Luo Jun; Zhu Hang-Tian; Liu Quan-Lin; Liang Jing-Kui; Li Jing-Bo; Liu Guang-Yao

    2012-01-01

    Polycrystalline p-type Ag0.9Sb1.1-xMnx Te2.05 (x =0.05,0.10,and 0.20) compounds have been prepared by a combined process of melt-quenching and spark plasma sintering.The sample composition of Ag0.9Sb1.1-xMnx Te2.05 has been specially designed in order to achieve the doping effect by replacing part of Sb with Mn and to present the uniformly dispersed Ag2 Te phase in the matrix by adding insufficient Te,which is beneficial for optimizing the electrical transport properties and enhancing the phonon scattering effect.All the samples have the NaCl-type structure according to our X-ray powder diffraction analysis.After the treatment of spark plasma sintering,only the sample with x =0.20 has a small amount of MnTe2 impurities.The thermal analysis indicates that a tiny amount of Ag2Te phase exists in all these samples.The presence of the MnTe2 impurity with high resistance and high thermal conductivity leads to the deteriorative thermoelectric performance of the sample with x =0.20 due to the decreased electrical transport properties and the increased thermal conductivity.In contrast,the sample with x =0.10 exhibits enhanced thermoeletric properties due to the Mn-doping effect.A dimensionless thermoelectric figure of merit of 1.2 is attained for the sample with x =0.10 at 573 K,showing promising thermoelectric properties in the medium temperature range.

  7. 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.

  8. Increased spectral sensitivity of Si photodetector by surface plasmon effect of Ag nanowires

    Science.gov (United States)

    Kim, Hong-Sik; Kumar, Melvin David; Kim, Hyunki; Kim, Joondong

    2016-05-01

    Highly-sensitive Si photodetectors were prepared by using Ag nanowires (AgNWs). A transparent indium-tin-oxide (ITO) coating was coated on a Si substrate followed by spin-coating of AgNWs-containing solution. AgNWs having average length of 5-20 μm with a diameter of about 40-60 nm were observed in FESEM images. The haze effect of AgNWs was totally avoided because of the optimum value of diameter. The transmittance of above 85% was shown by AgNWs over a broad spectral range due to surface plasmon resonance effect. The AgNW-coated device showed an excellent rectifying ratio of 288. Under light illumination, AgNWs-coated device exhibited a significant photoresponse ratio of 5373. This advanced feature of AgNWs-templated method would be applied in broadband wavelength photodetection devices.

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

    Science.gov (United States)

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

    2016-08-17

    Hydrogen is regarded as a future sustainable and clean energy carrier. Formic acid is a safe and sustainable hydrogen storage medium with many advantages, including high hydrogen content, nontoxicity, and low cost. In this work, a series of highly active catalysts for hydrogen production from formic acid are successfully synthesized by controllably depositing Pd onto Ag nanoplates with different Ag nanofacets, such as Ag{111}, Ag{100}, and the nanofacet on hexagonal close packing Ag crystal (Ag{hcp}). Then, the Pd-Ag nanoplate catalysts are supported on Vulcan XC-72 carbon black to prevent the aggregation of the catalysts. The research reveals that the high activity is attributed to the formation of Pd-Ag alloy nanofacets, such as Pd-Ag{111}, Pd-Ag{100}, and Pd-Ag{hcp}. The activity order of these Pd-decorated Ag nanofacets is Pd-Ag{hcp} > Pd-Ag{111} > Pd-Ag{100}. Particularly, the activity of Pd-Ag{hcp} is up to an extremely high value, i.e., TOF{hcp} = 19 000 ± 1630 h(-1) at 90 °C (lower limit value), which is more than 800 times higher than our previous quasi-spherical Pd-Ag alloy nanocatalyst. The initial activity of Pd-Ag{hcp} even reaches (3.13 ± 0.19) × 10(6) h(-1) at 90 °C. This research not only presents highly active catalysts for hydrogen generation but also shows that the facet on the hcp Ag crystal can act as a potentially highly active catalyst. PMID:27454194

  10. Photoelectron Imaging of AgOCH3- and Ag-(CH3OH)x (x=1, 2)

    Institute of Scientific and Technical Information of China (English)

    Chao-xian Chi; Hua Xie; Ran Cong; Zi-chao Tang; Ming-fei Zhou

    2011-01-01

    The AgOCH3- and Ag-(CH3OH)x (x=1,2) anions are studied by photoelectron imaging as well as ab initio calculations.The adiabatic and vertical detachment energies (ADE and VDE) of AgOCH3- are determined as 1.29(2) and 1.34(2) eV,respectively,from the vibrational resolved photoelectron spectrum.The Ag-(CH3OH)1,2 anionic complexes are characterized as metal atomic anion solvated by the CH3OH molecules with the electron mainly localized on the metal.The photoelectron spectra of Ag-(CH3OH)x (x=0,1,2)show a gradual increase in VDE with increasing x,due to the solvent stabilization.Evidence for the methanol-methanol hydrogen bonding interactions appears when the Ag- is solvated by two methanol molecules.

  11. Urchin-like m-LaVO4 and m-LaVO4/Ag microspheres: Synthesis and characterization

    International Nuclear Information System (INIS)

    The semiconductor nanostructures decorated with noble metals have attracted increasing attention due to their interesting physical and chemical properties. In this work, urchin-like monoclinic (m-) LaVO4 microspheres were prepared by a hydrothermal method and used as a template to fabricate Ag nanoparticle-decorated m-LaVO4 composites. The morphology and structure were characterized by transmission electron microscope, high-resolution transmission electron microscope, scanning electron microscope, and energy-dispersive X-ray. It was found that Ag nanoparticles with narrow size distribution were uniformly loaded on urchin-like m-LaVO4 microspheres, and the resulted composite microspheres showed distinct surface plasmon absorption band compared to pure m-LaVO4 microspheres. Photocatalytic activities of as-prepared samples were examined by studying the degradation of methyl orange solutions under visible-light irradiation (> 400 nm). Results clearly showed that urchin-like m-LaVO4/Ag microspheres possess much higher photocatalytic activity than pure m-LaVO4 microspheres and P25. - Highlights: • m-LaVO4/Ag composites microspheres were fabricated by a hydrothermal method. • m-LaVO4 microspheres show higher photocatalytic activity than m-LaVO4 microspheres. • m-LaVO4/Ag microspheres exhibit a good stability

  12. Large transport current density in bulk oriented-grained 123/Ag composites

    International Nuclear Information System (INIS)

    This paper reports on ceramic high temperature superconductors (HTS) that are inherently inferior in their mechanical properties. Addition of silver in bulk HTS has been shown to improve their mechanical properties. However, these HTS/Ag composites possess low transport critical current density typical of polycrystalline HTS. This paper deals with the development of a liquid-phase processing method that results in oriented-grained 123/Ag composites with large current carrying capability and enhanced mechanical properties. In this method, composites of 123 superconductor with up to 25 wt.% Ag addition are subjected to liquid-phase processing in air. Oriented-grained samples up to 10 mm long are obtained with Ag particles dispersed throughout the composites. Measurements on these oriented-grained samples using continuous direct current at 77K and zero applied magnetic field routinely give a transport critical current density in excess of 15,000 A/cm2. Magnetization measurements, however, show a Jc of 30,000 A/cm2 at 2 tesla. These results along with improved mechanical properties make these composites promising for bulk superconductivity applications. This work is supported by DARPA and the state of Texas

  13. Phase transitions in CuS-Ag2S nanoparticle system

    Science.gov (United States)

    Sheela Christy, R.; Thanka Kumaran, J. T.; Bansal, C.; Brightson, M.

    2016-02-01

    (Ag2)xCu1-xS, x = .2, .4, .6 and .8 nanoparticles were synthesized by the solvothermal method. The as-synthesized nanoparticles were characterized by X-ray diffraction to study the crystal structure and size. The surface morphologies of the above samples were studied using scanning electron microscope. As there is continuous shift in the lower wavelength absorption edge of the UV-VIS spectrum of these samples with concentration, (Ag2)xCu1-xS nanoparticles can be tuned to different band gap energies by varying the composition. The D.C. electrical resistance was measured in the temperature range 310-485 K. As Ag2S transforms from monoclinic to bcc at around 450 K, copper sulfide nanoparticles also shows a phase transition at around 470 K, the effects of these two transitions are seen in the resistance measurements and in the UV-VIS spectra of the entire system. The electrical resistance of (Ag2)xCu1-xS nanoparticles rapidly reduces as more and more copper sulfide is added.

  14. Magnetic microstructures from magnetic force microscopy and Monte Carlo simulation in CoFe-Ag-Cu granular films

    OpenAIRE

    Batlle Gelabert, Xavier; Valencia, A.; Labarta, Amílcar; O'Grady, K; Watson, M L

    1998-01-01

    CoFe-Ag-Cu granular films, prepared by rf sputtering, displayed magnetic domain microstructures for ferromagnetic concentrations above about 32% at, and below the percolation threshold. All samples have a fcc structure with an (111) texture perpendicular to the film plane. Magnetic force microscopy (MFM) showed a variety of magnetic domain microstructures, extremely sensitive to the magnetic history of the sample, which arise from the balance of the ferromagnetic exchange, the dipolar interac...

  15. Development of Ag dendrites-reduced graphene oxide composite catalysts via galvanic replacement reaction

    Science.gov (United States)

    Fu, Li; Sokiransky, Mika Matsunaka; Wang, James; Lai, Guosong; Yu, Aimin

    2016-09-01

    Silver dendrites/reduced graphene oxide (AgD/RGO) composites were synthesized via a facile galvanic replacement method. The successful formation of Ag dendrites and the graphene oxide reduction were proved by a series of characterization techniques. The possible formation mechanism of Ag dendrites during the galvanic replacement reaction was discussed. The catalytic activity of the as-synthesized AgD/RGO composite was evaluated by its performance on the chemical reduction of an organic dye methylene blue. The AgD/RGO composite showed a much higher catalytic performance and stability than that of Ag dendrites.

  16. Exposure Medium: Key in Identifying Free Ag+ as the Exclusive Species of Silver Nanoparticles with Acute Toxicity to Daphnia magna

    Science.gov (United States)

    Shen, Mo-Hai; Zhou, Xiao-Xia; Yang, Xiao-Ya; Chao, Jing-Bo; Liu, Rui; Liu, Jing-Fu

    2015-04-01

    It is still not very clear what roles the various Ag species play in the toxicity of silver nanoparticles (AgNPs). In this study, we found that traditional exposure media result in uncontrollable but consistent physicochemical transformation of AgNPs, causing artifacts in determination of median lethal concentration (LC50) and hindering the identification of Ag species responsible for the acute toxicity of AgNPs to Daphnia magna. This obstacle was overcome by using 8 h exposure in 0.1 mmol L-1 NaNO3 medium, in which we measured the 8-h LC50 of seven AgNPs with different sizes and coatings, and determined the concentrations of various Ag species. The LC50 as free Ag+ of the seven AgNPs (0.37-0.44 μg L-1) agreed very well with that of AgNO3 (0.40 μg L-1), and showed the lowest value compared to that as total Ag, total Ag+, and dissolved Ag, demonstrating free Ag+ is exclusively responsible for the acute toxicity of AgNPs to D. magna, while other Ag species in AgNPs have no contribution to the acute toxicity. Our results demonstrated the great importance of developing appropriate exposure media for evaluating risk of nanomaterials.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kumaran, R.; Alagar, M. [Polymer Composite Laboratory, Department of Chemical Engineering, Anna University, Chennai 600 025 (India); Dinesh Kumar, S.; Subramanian, V. [Microwave Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India); Dinakaran, K., E-mail: kdinakaran.tvu@gmail.com [Department of Chemistry, Thiruvalluvar University, Serkkadu, Vellore 632115 (India)

    2015-09-14

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

  18. Ag nanoparticles formed by femtosecond pulse laser ablation in water: self-assembled fractal structures

    Energy Technology Data Exchange (ETDEWEB)

    Santillán, Jesica M. J. [CONICET La Plata-CIC, Centro de Investigaciones Ópticas (CIOp) (Argentina); Fernández van Raap, Marcela B., E-mail: raap@fisica.unlp.edu.ar; Mendoza Zélis, Pedro; Coral, Diego [CONICET, Instituto de Física La Plata (IFLP) (Argentina); Muraca, Diego [Universidade Estadual de Campinas, Instituto de Física “Gleb Wataghin” (IFGW) (Brazil); Schinca, Daniel C.; Scaffardi, Lucía B., E-mail: lucias@ciop.unlp.edu.ar [CONICET La Plata-CIC, Centro de Investigaciones Ópticas (CIOp) (Argentina)

    2015-02-15

    We report for the first time on the formation of self-assembled fractals of spherical Ag nanoparticles (Nps) fabricated by femtosecond pulse laser ablation of a solid silver target in water. Fractal structures grew both in two and three Euclidean dimensions (d). Ramified-fractal assemblies of 2 nm height and 5–14 μm large, decorated with Ag Nps of 3 nm size, were obtained in a 2d geometry when highly diluted drops of colloidal suspension were dried at a fast heating rate over a mica substrate. When less-diluted drops were dried at slow heating rate, isolated single Nps or rosette-like structures were formed. Fractal aggregates about 31 nm size in 3d geometry were observed in the as-prepared colloidal suspension. Electron diffraction and optical extinction spectroscopy (OES) analyses performed on the samples confirmed the presence of Ag and Ag{sub 2}O. The analysis of the optical extinction spectrum, using the electrostatic approximation of Mie theory for small spheres, showed the existence of Ag bare core, Ag–Ag{sub 2}O and air–Ag core–shell Nps, Ag–Ag{sub 2}O being the most frequent type [69 % relative abundance (r.a.)]. Core-size and shell-thickness distribution was derived from OES. In situ scattering measurements of the Ag colloidal suspension, carried out by small-angle X-ray scattering, indicate a mass fractal composed of packaged 〈D{sub SAXS}〉 = (5 ± 1) nm particles and fractal dimension d{sub f} = 2.5. Ex situ atomic force microscopy imaging displayed well-ramified structures, which, analyzed with box-counting method, yield a fractal dimension d{sub f} = 1.67. The growing behavior of these 2d and 3d self-assembled fractals is consistent with the diffusion-limited aggregation model.

  19. 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.

  20. The role of Ag in (Ag,Cu)2ZnSnS4 thin film for solar cell application

    International Nuclear Information System (INIS)

    Highlights: • (Ag,Cu)2ZnSnS4 thin film was synthesized through metallic stacking layers. • Ag incorporation reduces the size and amount of voids at back contact. • Less planar defects and Cu vacancy are formed in the (Ag,Cu)2ZnSnS4. • Solar cell performance was improved with Ag incorporation. - Abstract: Recently, Ag incorporation into Cu(In,Ga)Se2 structure was found to benefit the solar cell performance. However, (Ag,Cu)2ZnSnS4 used as the solar cell absorber is not widely reported even though Ag2ZnSnS4 has shown much better photocatalysts activity for H2 evolution than Cu2ZnSnS4. In this paper, (Ag,Cu)2ZnSnS4 thin film solar cell was synthesized through sulfurization of Ag/Zn/Cu/Sn metallic stacked layers. In order to understand the actual role of Ag in the Cu2ZnSnS4 structure, the changing chemical environment, microstructure and intragrain defect due to the Ag incorporation, were studied by X-ray photoelectron spectroscopy and transmission electron microscopy. After sulfurization, Ag is uniformly distributed in the absorber and is incorporated into Cu2ZnSnS4 crystal structure but no obvious change of the Cu2ZnSnS4 chemical environment is detected. A large density of voids is formed at the Cu2ZnSnS4/Mo interface and some of these voids are found to be coated with CdS which is believed to be detrimental to Cu2ZnSnS4 device performance. In contrast, Ag incorporation reduces the size and amount of voids and thus effectively eliminates CdS deposited at back contact region. Moreover, fewer planar defects and Cu vacancies are formed in the (Ag,Cu)2ZnSnS4 sample than Cu2ZnSnS4 sample as suggested by electron diffraction patterns. Therefore, improved solar cell performance should result from the formation of (Ag,Cu)2ZnSnS4 structure

  1. Synthesis and Characterization of High Efficiency and Stable Spherical Ag3PO4 Visible Light Photocatalyst for the Degradation of Methylene Blue Solutions

    Directory of Open Access Journals (Sweden)

    Liqin Qin

    2015-01-01

    Full Text Available A facile method for the synthesis of Ag3PO4 visible light photocatalyst has been developed to improve the photocatalytic activity and stability. The as-prepared samples are investigated by X-ray powder diffraction, scanning electron microscopy, infrared spectroscopy, photoluminescence (PL spectroscopy, and UV-Vis diffuse reflectance spectroscopy techniques. The results reveal that the prepared Ag3PO4 has cube structure with a band gap of 2.26 eV. The as-prepared samples show higher photocatalytic activity for methylene blue (MB degradation than that of N-TiO2 under visible light irradiation.

  2. Geometry optimization and structural distribution of silver clusters from Ag 170 to Ag 310

    Science.gov (United States)

    Shao, Xueguang; Yang, Xiaoli; Cai, Wensheng

    2008-07-01

    Silver clusters in the size range of 170-310 were optimized with a modified dynamic lattice search (DLS) method. Considering the computational complexity, only 21 clusters of several tens and magic numbers of atoms were investigated. The interaction of silver atoms is modeled by the Gupta potential. Results show that, between the 21 clusters, nine fcc and twelve m-Dh structures are obtained. Compared with the structures adopted by Ag 13 to Ag 160, the main motif is still m-Dh in the range of Ag 170-Ag 310, but the ratio of fcc structures obviously increases. It can, therefore, be deduced that the fcc motif is more stable for larger size silver clusters.

  3. Ferromagnetic resonance of ultrathin Co /Ag superlattices on Si(111)

    Science.gov (United States)

    Kakazei, G. N.; Martin, P. P.; Ruiz, A.; Varela, M.; Alonso, M.; Paz, E.; Palomares, F. J.; Cebollada, F.; Rubinger, R. M.; Carmo, M. C.; Sobolev, N. A.

    2008-04-01

    Ferromagnetic resonance (FMR) is used to probe the magnetic properties of Co /Ag superlattices (SLs) with ultrathin Co layers (2-6Å). Different series of 5×[Ag/Co] multilayers have been grown by molecular beam epitaxy on Si(111) substrates, monitoring the growth by reflection high energy electron diffraction. Cross-section transmission electron microscopy confirms the growth of local areas with the designed SL periodicity, a sharp compositional modulation, well defined Ag-Co interfaces, and a perfect fcc (111) stacking. FMR spectra have been recorded at various polar angles in the 0°-90° range. A single and extremely broad resonance peak is observed in all cases. While SLs with Ag layers thinner than 10Å exhibit similar values of the perpendicular anisotropy, a clear reduction is observed for samples with Ag layers about 14Å thick. Possible causes for this change are discussed.

  4. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

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

  5. Irradiation induced dissolution of Cu and growth of Ag nanoclusters in Cu/Ag ion-exchanged soda-lime glass

    CERN Document Server

    Manikandan, D; Magudapathy, P; Nair, K G M

    2002-01-01

    Complex metal nanoclusters of Cu/Ag are formed in a soda-lime glass matrix by sequential copper and silver ion-exchange followed by ion irradiation. Optical absorption measurements showed signature of copper clusters alone in the Cu/Ag ion-exchanged sample. Irradiation of the ion-exchanged sample with He sup + ions of energy 100 keV of different fluences resulted in the growth of the silver clusters with, the optical absorption spectrum exhibiting two peaks corresponding to the surface plasmon resonance of copper and silver in the same matrix. It was found that with increase in fluence the silver clusters begin to grow while the already formed copper clusters segregate, which can be visualized from the absorption spectra, where the copper band disappears while the silver band grows with the increase in dose. Vacuum annealing of the Cu/Ag ion-exchanged samples resulted in complete disappearance of copper clusters while the silver clusters grew till they attained saturation. The glancing incidence X-ray diffrac...

  6. Ag-SBA-15抗菌剂的制备及其性能研究%Studies on the preparation and performance of Ag-SBA-15 antibacterial agent

    Institute of Scientific and Technical Information of China (English)

    丁志杰; 马忠友; 郭雨; 郭腾; 陈君华

    2016-01-01

    以板状和纤维状SBA-15为载体,采用正己烷为疏水溶剂、硝酸银的水溶液为亲水溶剂的双溶剂法制备了广谱抗菌剂板状Ag-SBA-15和纤维状Ag-SBA-15。以X射线衍射、扫描电子显微镜、透射电子显微镜和X射线能谱等手段表征了抗菌剂的结构和特性。通过试管稀释法考察了抗菌剂抗菌性能。结果显示,两种形貌SBA-15为载体制得的Ag-SBA-15都保持高度有序的二维六方相介孔结构,银颗粒在载体中均匀分散。试管稀释法测得由板状SBA-15制得抗菌剂对金黄色葡萄球菌的最小抑菌浓度达8ug/mL,而相应条件下由传统纤维状SBA-15为载体制得的抗菌剂最小抑菌浓度为32ug/mL。%Using platelet SBA-15 and fiber SBA-15 as carriers,platelet Ag-SBA-15 and fiber Ag-SBA-15 with the broad-spectrum antibacterial activity were prepared by a double solvent technique,in which n-hexane is used as a hydrophobic solvent and AgNO3 solution is used as a hydrophilic solvent. The structure of samples was investigated by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and energy dispersive spectrometer(EDS). The antibacterial effect of Ag-SBA-15 was investigated by the tube dilution method. The results showed that Ag-SBA-15 with highly ordered two-dimensional hexagonal structure was synthesized using platelet and fiber SBA-15 as support respectively. Silver nanoparticles were uniformly loaded on the porous support. The tube dilution method showed the minimal inhibitory concentration( MIC) of platelet Ag-SBA-15 for Staphylococcus? aureus is 8ug/mL,whereas the MIC of conventional fiber Ag-SBA-15 is 32ug/mL.

  7. [Study on the development of Ag-nano-hydroxyapatite/polyamide66 porous scaffolds with surface mineralization].

    Science.gov (United States)

    Fan, Jianbo; Chang, Shan; Dong, Mina; Huang, Di; Li, Jidong; Jiang, Dianming

    2012-12-01

    Bacterial infection after implantation of bone tissue engineering scaffolds is still a serious clinical problem. Ag-nano-hydroxyapatite/polyamide66 (Ag-nHA/PA66) antibacterial composite scaffold were prepared with phase-inversion method in this study. The scaffolds were mineralized in saturated calcium phosphate solution at 37 degrees C for 1 day. The microstructure and the newly formed nano-apatite deposition on the scaffolds before and after mineralization were observed using scanning electron microscopy (SEM). In order to investigate the release behaviors of Ag+, the Ag-nHA/PA66 scaffolds were immersed into 5 ml PBS at 37 degrees C for a different period between 3 h and 168 h before and after mineralization. Then the samples were cultured with E. coli (8099) to test the antibacterial effect of the scaffolds. The results showed that, after mineralization, Ag-nHA/PA66 porous scaffolds still possessed a good inter-connection and a new apatite layer was formed on the surface of the scaffolds. The average macropore size was 626.61 +/- 141.94 microm, the porosity was 76.89 +/- 8.21% and the compressive strength was 2.94 +/- 1.12 MPa. All these physical parameters had no significant difference from those of the un-mineralized scaffolds. The Ag+ release of the scaffolds with and without mineralization was fast within 1 day and then kept slow and stable after 1 day. The antibacterial test confirmed that after mineralization the scaffolds had good antibacterial effects on E. coli. PMID:23469542

  8. Heavy metal tolerance (Cr, Ag and Hg in bacteria isolated from sewage

    Directory of Open Access Journals (Sweden)

    Agostinho A. de Lima e Silva

    2012-12-01

    Full Text Available Samples of sewage from a university hospital and a chemistry technical school were analysed for the percentage of bacterial tolerance to chromium (Cr, silver (Ag and mercury (Hg. Additionally, we investigated the effect of these metals on pigmentation and on some enzymatic activities of the metal tolerant strains isolated, as well as antimicrobial resistance in some metal tolerant Enterobacteriaceae strains. Tolerance to Cr was observed mainly in Gram positive bacteria while in the case of Ag and Hg the tolerant bacteria were predominately Gram negative. Hg was the metal for which the percentage of tolerance was significantly higher, especially in samples from the hospital sewage (4.1%. Mercury also had the most discernible effect on color of the colonies. Considering the effect of metals on the respiratory enzymes, one strain of Ag-tolerantBacillus sp. and one of Hg-tolerant P. aeruginosa were unable to produce oxidase in the presence of Ag and Hg, respectively, while the expression of gelatinase was largely inhibited in various Gram negative strains (66% by Cr. Drug resistance in Hg-tolerant Enterobacteriaceae strains isolated from the university hospital sewage was greater than 80%, with prevalence of multiple resistance, while the Ag-tolerant strains from the same source showed about 34% of resistance, with the predominance of mono-resistance. Our results showed that, despite the ability of metal tolerant strains to survive and grow in the presence of these elements, the interactions with these metals may result in metabolic or phisiological changes in this group of bacteria.

  9. Heavy metal tolerance (Cr, Ag AND Hg) in bacteria isolated from sewage.

    Science.gov (United States)

    Lima de Silva, Agostinho A; de Carvalho, Márcia A Ribeiro; de Souza, Sérgio A L; Dias, Patrícia M Teixeira; da Silva Filho, Renato G; de Meirelles Saramago, Carmen S; de Melo Bento, Cleonice A; Hofer, Ernesto

    2012-10-01

    Samples of sewage from a university hospital and a chemistry technical school were analysed for the percentage of bacterial tolerance to chromium (Cr), silver (Ag) and mercury (Hg). Additionally, we investigated the effect of these metals on pigmentation and on some enzymatic activities of the metal tolerant strains isolated, as well as antimicrobial resistance in some metal tolerant Enterobacteriaceae strains. Tolerance to Cr was observed mainly in Gram positive bacteria while in the case of Ag and Hg the tolerant bacteria were predominately Gram negative. Hg was the metal for which the percentage of tolerance was significantly higher, especially in samples from the hospital sewage (4.1%). Mercury also had the most discernible effect on color of the colonies. Considering the effect of metals on the respiratory enzymes, one strain of Ag-tolerant Bacillus sp. and one of Hg-tolerant P. aeruginosa were unable to produce oxidase in the presence of Ag and Hg, respectively, while the expression of gelatinase was largely inhibited in various Gram negative strains (66% by Cr). Drug resistance in Hg-tolerant Enterobacteriaceae strains isolated from the university hospital sewage was greater than 80%, with prevalence of multiple resistance, while the Ag-tolerant strains from the same source showed about 34% of resistance, with the predominance of mono-resistance. Our results showed that, despite the ability of metal tolerant strains to survive and grow in the presence of these elements, the interactions with these metals may result in metabolic or phisiological changes in this group of bacteria.

  10. Curve thermoluminescent analysis of ZrO{sub 2} doped with nanoparticles and Ag nano fibers; Analisis de la curva termoluminiscente de la ZrO{sub 2} dopada con nanoparticulas y nanofibras de Ag

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza A, D.; Villa S, G.; Gutierrez W, C.; Perez H, R.; Gonzalez M, P. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico)

    2008-07-01

    This paper presents the results obtained from the analysis of the high temperature thermoluminescence response induced by UV radiation in pure zirconium (ZrO{sub 2}) and doped with Ag nanoparticles and Ag nano fibers. The zirconium samples were obtained by the sol-gel method and irradiated with a UV lamp for different times. The results showed that the presence of the dopants change the characteristics of the traps associated with the high temperature peak which is located at 230 C for pure zirconium, and that the greater influence is due the presence of Ag nano fibers, inducing a shift to lower temperatures. It also presents the thermoluminescence response as a function of irradiation time. (Author)

  11. AGS experiments: 1990, 1991, 1992

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Bicho, Rita C; Ribeiro, Tânia; Rodrigues, Natália P; Scott-Fordsmand, Janeck J; Amorim, Mónica J B

    2016-11-15

    Information on effects of silver nanoparticles on soil invertebrates, especially using long-term exposures, is scarce. In this study we investigated the effects of the reference Ag (NM300K) (compared to AgNO3) using the full life cycle test (FLCt) of the soil invertebrate Enchytraeus crypticus. 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 be discriminated using the FLCt: AgNO3 decreased hatching success was shown to be a delay in the process, whereas Ag NM300K caused irreversible effects during the same time frame. These effects may have occurred during the embryo development, hatching (inhibition) or survival of hatched juveniles. Ag NM300K caused non-monotonic concentration-response effect as observed by the high effect of the lowest concentration (20mgkg-1). It is known that dispersion is higher at lower concentrations - this could explain the increased effect at low concentration. Non monotonic responses are well described in the literature, where effects of high cannot predict for low concentrations, hence special attention should be given for NMs low concentration effects. PMID:27474850

  13. Room Temperature Synthesis and Catalytic Properties of Surfactant-Modified Ag Nanoparticles

    Directory of Open Access Journals (Sweden)

    Weihua Li

    2012-01-01

    Full Text Available Well-dispersed Ag nanoparticles with size of 20–30 nm were synthesized in water at room temperature with a self-made novel imidazoline Gemini surfactant quaternary ammonium salt of di (2-heptadecyl-1-formyl aminoethyl imidazoline hexanediamine. Transmission electron microscopy, X-ray powder diffraction, ultraviolet-visible absorption spectra, and Fourier transform infrared ray were used to characterize the Ag nanoparticles. Results showed that the micellized aggregation of imidazoline Gemini surfactant in water, the growth of Ag initial particles, and the interaction (adsorption and coordination between surfactant and Ag+/Ag nanoparticles took place simultaneously to form the well-dispersed Ag nanoparticles. Catalytic results show that the surface-modified Ag product was an active metal catalyst for methyl orange reduction reaction due to the effective adsorption between Ag nanoparticles and methyl orange molecules, which was of promising application in environmental protection.

  14. An oil-in-water self-assembly synthesis, characterization and photocatalytic properties of nano Ag@AgCl surface-sensitized K{sub 2}Ti{sub 4}O{sub 9}

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Yinghua; Lin, Shuanglong; Liu, Li, E-mail: chemll@126.com; Hu, Jinshan; Cui, Wenquan, E-mail: wkcui@163.com

    2014-12-15

    Highlights: • The plasmatic Ag@AgCl surface-sensitized K{sub 2}Ti{sub 4}O{sub 9} composite photocatalysts. • Ag@AgCl greatly increased visible light absorption for K{sub 2}Ti{sub 4}O{sub 9}. • The photocatalysts exhibited enhanced photocatalytic dye degradation. - Abstract: Nano-sized plasmonic Ag@AgCl surface-sensitized K{sub 2}Ti{sub 4}O{sub 9} composite photocatalysts (hereafter designated as Ag@AgCl/K{sub 2}Ti{sub 4}O{sub 9}) was synthesized via a facile oil-in-water self-assembly method. The photocatalytic activity of the prepared materials for RhB (Rhodamine B) degradation was examined under visible light irradiation. The results reveal that the size of Ag@AgCl, which evenly dispersed on the surface of K{sub 2}Ti{sub 4}O{sub 9}, distributes about 20–50 nm. The UV–vis diffuse reflectance spectra indicate that Ag@AgCl/K{sub 2}Ti{sub 4}O{sub 9} samples have a significantly enhanced optical absorption in 380–700 nm. The photocatalytic activities of the Ag@AgCl/K{sub 2}Ti{sub 4}O{sub 9} samples increase first and then decrease with increasing amount of loading Ag@AgCl and the Ag@AgCl(20 wt.%)/K{sub 2}Ti{sub 4}O{sub 9} sample exhibits the best photocatalytic activity and 94.47% RhB was degraded after irradiation for 2 h. Additionally, studies performed using radical scavengers indicated that O{sub 2}·{sup −} and Cl{sup 0} acted as the main reactive species. The electronic interaction was systematically studied and confirmed by the photo-electrochemical measurements.

  15. In situ growth of Ag nanoparticles on α-Ag2WO4 under electron irradiation: probing the physical principles.

    Science.gov (United States)

    San-Miguel, Miguel A; da Silva, Edison Z; Zannetti, Sonia M; Cilense, Mario; Fabbro, Maria T; Gracia, Lourdes; Andrés, Juan; Longo, Elson

    2016-06-01

    Exploiting the plasmonic behavior of Ag nanoparticles grown on α-Ag2WO4 is a widely employed strategy to produce efficient photocatalysts, ozone sensors, and bactericides. However, a description of the atomic and electronic structure of the semiconductor sites irradiated by electrons is still not available. Such a description is of great importance to understand the mechanisms underlying these physical processes and to improve the design of silver nanoparticles to enhance their activities. Motivated by this, we studied the growth of silver nanoparticles to investigate this novel class of phenomena using both transmission electron microscopy and field emission scanning electron microscopy. A theoretical framework based on density functional theory calculations (DFT), together with experimental analysis and measurements, were developed to examine the changes in the local geometrical and electronic structure of the materials. The physical principles for the formation of Ag nanoparticles on α-Ag2WO4 by electron beam irradiation are described. Quantum mechanical calculations based on DFT show that the (001) of α-Ag2WO4 displays Ag atoms with different coordination numbers. Some of them are able to diffuse out of the surface with a very low energy barrier (less than 0.1 eV), thus, initiating the growth of metallic Ag nanostructures and leaving Ag vacancies in the bulk material. These processes increase the structural disorder of α-Ag2WO4 as well as its electrical resistance as observed in the experimental measurements. PMID:27114472

  16. In situ growth of Ag nanoparticles on α-Ag2WO4 under electron irradiation: probing the physical principles

    Science.gov (United States)

    San-Miguel, Miguel A.; da Silva, Edison Z.; Zannetti, Sonia M.; Cilense, Mario; Fabbro, Maria T.; Gracia, Lourdes; Andrés, Juan; Longo, Elson

    2016-06-01

    Exploiting the plasmonic behavior of Ag nanoparticles grown on α-Ag2WO4 is a widely employed strategy to produce efficient photocatalysts, ozone sensors, and bactericides. However, a description of the atomic and electronic structure of the semiconductor sites irradiated by electrons is still not available. Such a description is of great importance to understand the mechanisms underlying these physical processes and to improve the design of silver nanoparticles to enhance their activities. Motivated by this, we studied the growth of silver nanoparticles to investigate this novel class of phenomena using both transmission electron microscopy and field emission scanning electron microscopy. A theoretical framework based on density functional theory calculations (DFT), together with experimental analysis and measurements, were developed to examine the changes in the local geometrical and electronic structure of the materials. The physical principles for the formation of Ag nanoparticles on α-Ag2WO4 by electron beam irradiation are described. Quantum mechanical calculations based on DFT show that the (001) of α-Ag2WO4 displays Ag atoms with different coordination numbers. Some of them are able to diffuse out of the surface with a very low energy barrier (less than 0.1 eV), thus, initiating the growth of metallic Ag nanostructures and leaving Ag vacancies in the bulk material. These processes increase the structural disorder of α-Ag2WO4 as well as its electrical resistance as observed in the experimental measurements.

  17. 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.

  18. 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.

  19. A novel green synthesis of Fe{sub 3}O{sub 4}-Ag core shell recyclable nanoparticles using Vitis vinifera stem extract and its enhanced antibacterial performance

    Energy Technology Data Exchange (ETDEWEB)

    Venkateswarlu, Sada; Natesh Kumar, B.; Prathima, B. [Analytical and inorganic Division of Chemistry, S.V. University, Tirupati-517502, Andhra Pradesh (India); Anitha, K. [Department of Chemistry, S.K. University, Anantapur-515003, Andhra Pradesh (India); Jyothi, N.V.V., E-mail: nvvjyothi01@gmail.com [Analytical and inorganic Division of Chemistry, S.V. University, Tirupati-517502, Andhra Pradesh (India)

    2015-01-15

    We described a novel and eco-friendly method for preparing Fe{sub 3}O{sub 4}-Ag core shell nanoparticles (CSNPs) with high magnetism and potent antibacterial activity. The Fe{sub 3}O{sub 4}-Ag CSNPs were obtained using waste material of Vitis vinifera (grape) stem extract as the green solvent, reducing and capping agent. The result recorded from X-ray powder diffraction (XRD), UV–vis spectrum, energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR) supports the biosynthesis and characterization of Fe{sub 3}O{sub 4}-Ag CSNPs. From transmission electron microscopy (TEM) the size of the Fe{sub 3}O{sub 4}-Ag nanoparticles was measured below 50 nm; high-resolution TEM (HRTEM) indicates the core shell structure; and selected area electron diffraction (SAED) has revealed polycrystalline nature. Vibrating sample magnetometer (VSM) shows the ferromagnetic nature of Fe{sub 3}O{sub 4}-Ag CSNPs at room temperature with saturation magnetization of 15.74 emu/g. Further, these biogenic nanoparticles were highly hazardous to microorganisms. The antibacterial activity of biogenic Fe{sub 3}O{sub 4}-Ag CSNPs showed potent inhibitory activity against both Gram-positive and Gram-negative pathogens. These nanoparticles may also be reusable because of its excellent ferromagnetic property.

  20. Improved nonlinear optical and optical limiting properties in non-covalent functionalized reduced graphene oxide/silver nanoparticle (NF-RGO/Ag-NPs) hybrid

    Science.gov (United States)

    Sakho, El hadji Mamour; Oluwafemi, Oluwatobi S.; Sreekanth, P.; Philip, Reji; Thomas, Sabu; Kalarikkal, Nandakumar

    2016-08-01

    Nonlinear optical (NLO) response under near infrared (800 nm) and visible (532 nm) laser excitations, of 100 fs (fs) and 5 ns (ns) pulse durations respectively, of reduced graphene oxide (RGO), non-covalent functionalized reduced graphene oxide (NF-RGO) and NF-RGO decorated with various concentration of silver nanoparticles (NF-RGO/Ag-NPs) have been investigated using the Open-aperture Z-Scan technique. For both femtosecond and nanosecond laser excitations, the studied graphene-based materials exhibit good nonlinear optical power limiting properties (OL), with NF-RGO/Ag-NPs sample prepared with 0.1 M AgNO3 showing the best nonlinear optical properties. For the ns regime, the optical limiting threshold decreased from 8.3 J/cm2 in NF-RGO to 4.3 J/cm2 in NF-RGO/Ag-NPs, while at fs regime, the nonlinear absorption coefficient (β) was found to increase with decrease in concentration of Ag-NPs in the hybrid. Two-photon absorption (2 PA) in combination with saturable absorption (SA) in femtosecond regime, and reverse saturable absorption (RSA) along with saturable absorption (SA) in the nanosecond regime, are responsible for the observed nonlinear optical absorption (NLA) behavior in these materials. These findings show that the as-synthesized NF-RGO/Ag-NPs hybrid is a relatively better material for nonlinear optical limiting applications.

  1. A low proportion of HBeAg among HBsAg-positive pregnant women with known HIV status could suggest low perinatal transmission of HBV in Cameroon

    Directory of Open Access Journals (Sweden)

    Kfutwah Anfumbom KW

    2012-03-01

    Full Text Available Abstract Background Transmission of hepatitis B virus (HBV from HBV-positive mothers to their infants is common and usually occurs when the mother is hepatitis B e antigen (HBeAg positive and/or has a high HBV DNA load. In this study, we determined the prevalence of hepatitis B surface antigen (HBsAg and HBeAg among pregnant women with known HIV status. Findings A total of 650 pregnant women with a mean age of 26.2 years including 301 HIV-positives and 349 HIV-negatives were screened for HBsAg (Monolisa AgHBs Plus Biorad, France. Among the HBsAg-positives, HBeAg and anti-HBe were tested (Monolisa Ag HBe Plus Biorad, France. Overall, 51 (7.85% were positive for HBsAg. The prevalence of HBsAg was not statistically different between HIV-positive and HIV-negative pregnant women [28/301 (9.3% vs 23/349 (6.59%; p = 0.2]. None of the 45 HBsAg-positive samples was reactive for HBeAg. Conclusions Our study indicates a high prevalence of HBsAg with very low proportion of HBeAg in Cameroonian pregnant women. Since perinatal transmission of HBV is mostly effective when the mother is also HBeAg-positive, our data could suggest that perinatal transmissions play a minor role in HBV prevalence in Cameroon. In line with previous African studies, these findings further suggests that horizontal transmission could be the most common mechanism of HBV infections in Cameroon.

  2. Synthesis and properties of polyamide–Ag2S composite based solar energy absorber surfaces

    NARCIS (Netherlands)

    Krylovaa, Valentina; Baltrusaitis, Jonas

    2013-01-01

    Silver sulfide (Ag2S), an efficient solar light absorber, was synthesized using a modified chemical bath deposition (CBD) method and polyamide 6 (PA) as a host material via solution phase reaction between AgNO3 and Na2S2O3. X-ray diffraction (XRD) data showed a single, α-Ag2S (acanthite), crystallin

  3. Hepatitis B Virus DNA in Blood Samples Positive for Antibodies to Core Antigen and Negative for Surface Antigen

    Science.gov (United States)

    Gutiérrez, C.; León, G.; Loureiro, C. L.; Uzcátegui, N.; Liprandi, F.; Pujol, F. H.

    1999-01-01

    Anti-hepatitis B core antigen (HBcAg)-positive hepatitis B surface antigen (HBsAg)-negative plasma samples from blood donors were tested by nested PCR. DNA positivity was more significantly associated with high levels of anti-HBcAg than with low levels of anti-HBsAg antibodies. Analysis of a dilution of anti-HBcAg antibodies might result in a more rational exclusion of anti-HBcAg-positive HBsAg-negative samples, reducing the number of donations discarded and enabling more countries to incorporate anti-HBcAg testing. PMID:10473534

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

    Science.gov (United States)

    Sinha, Sumona; Mukherjee, M.

    2015-10-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Sumona Sinha

    2015-10-01

    Full Text Available 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.

  6. 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.

  7. Breaking tolerance in hepatitis B surface antigen (HBsAg) transgenic mice by vaccination with cross-reactive, natural HBsAg variants

    DEFF Research Database (Denmark)

    Schirmbeck, Reinhold; Dikopoulos, Nektarios; Kwissa, Marcin;

    2003-01-01

    Processing exogenous hepatitis B surface antigen (HBsAg) of the hepatitis B virus (HBV) generates the K(b)-binding S(208-215) epitope 1; processing endogenous HBsAg generates the K(b)-binding S(190-197) epitope 2. Cross-reactive CD8(+) T cell responses were primed to epitope 1 but not epitope 2......-tg mice by HBsAg(adw2); these specific CD8(+) T cells cross-reacted with epitope 1 processed from the transgene-encoded HBsAg(ayw). The liver of vaccinated HBsAg(ayw) transgenic mice showed severe histopathology and contained functional (IFNgamma-producing), cross-reactive CD8(+) T cells, and vaccinated...... HBs-tg mice showed reduced antigenemia. Hence, vaccination with natural HBsAg variants from different HBV sero/genotypes can prime cross-reactive, specific CD8(+) T cell immunity that breaks tolerance to HBsAg....

  8. 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.

  9. Television Quiz Show Simulation

    Science.gov (United States)

    Hill, Jonnie Lynn

    2007-01-01

    This article explores the simulation of four television quiz shows for students in China studying English as a foreign language (EFL). It discusses the adaptation and implementation of television quiz shows and how the students reacted to them.

  10. AGS experiments - 1995, 1996 and 1997

    International Nuclear Information System (INIS)

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

  11. 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.

  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. Catalytic cracking of 1-butene to propylene by Ag modified HZSM-5

    Institute of Scientific and Technical Information of China (English)

    Rongrong Zhang; Zhengbao Wang

    2015-01-01

    Silver modified HZSM-5 (AgHZ) zeolite catalysts were prepared by ion exchange method and their catalytic properties in the 1-butene cracking reaction were measured. The catalysts were characterized by infrared spec-troscopy with pyridine adsorption (Py-IR), N2 adsorption and X-ray diffraction (XRD). The effects of Ag loading and steaming treatment on catalytic performances were studied. It is found that the activity of HZSM-5 (HZ) cat-alyst significantly decreases with the steaming time, whereas AgHZ catalysts show stable activity in the steaming time of 24–48 h and their activities increase with the Ag loading. When the steaming time is 24–48 h, the yield of propylene over HZ catalyst significantly decreases, whereas it is stable over AgHZ catalysts. The AgHZ catalysts with Ag loadings of 0.28%–0.43%(by mass) show similar propylene yields (~30%), which are higher than that over the AgHZ catalyst with a Ag loading of 0.55%(by mass). These results indicate that the steam-treated AgHZ catalysts with optimum Ag loadings have higher yield of propylene and are more stable than the steam-treated HZ catalyst. The regeneration stability measurement in butene cracking also shows that the AgHZ catalyst steam-treated under a suitable condition has better stability than the HZ catalyst.

  14. Structural, morphological and catalytic characterization of neutral Ag salt of 12-tungstophosphoric acid: Influence of preparation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Holclajtner-Antunović, Ivanka; Bajuk-Bogdanović, Danica [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade (Serbia); Popa, Alexandru [Institute of Chemistry Timişoara, Bl. Mihail Viteazul 24, 300223 Timişoara (Romania); Nedić Vasiljević, Bojana [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade (Serbia); Krstić, Jugoslav [Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11001 Belgrade (Serbia); Mentus, Slavko [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade (Serbia); Uskoković-Marković, Snežana, E-mail: snezaum@pharmacy.bg.ac.rs [Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade (Serbia)

    2015-02-15

    Graphical abstract: - Highlights: • Preparation conditions influence to self-assembly of nanocrystallites of Ag{sub 3}PW{sub 12}O{sub 40}. • Ag{sub 3}PW{sub 12}O{sub 40} obtained by filtration is microporous, Ag{sub 3}PW{sub 12}O{sub 40} obtained by evaporation is non-porous. • Thermal properties of Ag{sub 3}PW{sub 12}O{sub 40}, H{sub 3}PW{sub 12}O{sub 40} and its soluble salts are similar. - Abstract: The objective of this study is the structural and morphological characterization of the Ag{sub 3}PW{sub 12}O{sub 40} salts (AgWPA) of 12-tungstophosphoric acid (WPA) obtained under different preparation conditions and testing of their acid catalytic activity in dehydration of ethanol. The structure, morphology and physicochemical characteristics were determined by Fourier transform infrared (FT-IR) and Raman spectroscopy, X-ray diffraction (XRD), nitrogen physisorption at −196 °C, scanning electron microscopy (SEM) and differential thermal (DTA) and thermogravimetric analysis (TGA). It is shown that the preparation process has a significant influence on the morphological properties of the obtained materials which may be explained by the supposed mechanism of the formation of nanocrystallite′s aggregates with more or less epitaxial connection. Neutral AgWPA obtained by filtration from supernatant forms porous aggregates of a symmetric dodecahedral shape, having average sizes about 2 μm. This sample shows higher specific area in comparison with the salt obtained by evaporation due to the higher micropore volume, while mesopore volumes are the same for both salts. Thus conversion of ethanol and selectivities of the main products, ethylene and diethyl ether, are almost the same and constant for both prepared salts, while their values are changed over the reaction time for the parent WPA acid.

  15. Ag-loaded TiO2/reduced graphene oxide nanocomposites for enhanced visible-light photocatalytic activity

    Science.gov (United States)

    Vasilaki, E.; Georgaki, I.; Vernardou, D.; Vamvakaki, M.; Katsarakis, N.

    2015-10-01

    In this work, Ag nanoparticles were loaded by chemical reduction onto TiO2 P25 under different loadings ranging from 1 up to 4 wt% and hydrothermally deposited on reduced graphene oxide sheets. Chemical reduction was determined to be an effective preparation approach for Ag attachment to titania, leading to the formation of small silver nanoparticles with an average diameter of 4.2 nm. The photocatalytic performance of the hybrid nanocomposite materials was evaluated via methylene blue (MB) dye removal under visible-light irradiation. The rate of dye decolorization was found to depend on the metal loading, showing an increase till a threshold value of 3 wt%, above which the rate drops. Next, the as prepared sample of TiO2/Ag of better photocatalytic response, i.e., at a 3 wt% loading value, was hydrothermally deposited on a platform of reduced graphene oxide (rGO) of tunable content (mass ratio). TiO2/Ag/rGO coupled nanocomposite presented significantly enhanced photocatalytic activity compared to the TiO2/Ag, TiO2/rGO composites and bare P25 titania semiconductor photocatalysts. In particular, after 45 min of irradiation almost complete decolorization of the dye was observed for the TiO2/Ag/rGO nanocatalyst, while the respective removal efficiency was 92% for TiO2/Ag, 93% for TiO2/rGO and only 80% for the bare TiO2 nanoparticles. This simple step by step preparation strategy allows for optimum exploitation of the advanced properties of metal plasmonic effect and reduced graphene oxide as the critical host for boosting the overall photocatalytic activity towards visible-light.

  16. 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

  17. Electrical and optical characteristics of Ag/CdTe thin film structures

    International Nuclear Information System (INIS)

    Effect of Ag diffusion on electrical, optical and structural properties of Ag/CdTe structures have been investigated. In the range of 280-420 degrees Celsius the effective coefficient of thermal diffusion and photodiffusion are described. The acceleration of Ag diffusion under illumination was tentatively attributed to photoionization of Ag increasing the interstitial flux of silver. Ag/CdTe structures exposed to annealing were characterized by X-ray diffraction, conductivity-temperature and optical transmission measurements. In XRD patterns of annealed Ag/CdTe structures, besides the intensive peak of cubic CdTe, the weak peaks of Ag2Te phase are also present. The temperature dependence of conductivity and the absorption spectra of annealed Ag/CdTe structures showed the energy levels 0.13 eV and 0.10 eV respectively and nature of these levels were discussed

  18. Electrical and optical characteristics of Ag/CdTe thin film structures

    International Nuclear Information System (INIS)

    Full text : Effect of Ag diffusion on electrical, optical and structural properties of Ag/CdTe structures have been investigated. In the range of 280-420 degrees Celsius the effective coefficient of thermal diffusion and photodiffusion are described. The acceleration of Ag diffusion under illumination was tentatively attributed to photoionization of Ag increasing the interstitial flux of silver. Ag/CdTe structures exposed to annealing were characterized by X-ray diffraction (XRD), conductivity-temperature and optical transmission measurements. In XRD patterns of annealed Ag/CdTe structures, besides the intensive peak of cubic CdTe, the weak peaks of Ag2Te phase are also present. The temperature dependence of conductivity and the absorption spectra of annealed Ag/CdTe structures showed the energy levels 0.13 eV and 0.10 eV respectively and nature of these levels were discussed

  19. Transparent Conductive AGZO/Ag/AGZO Multilayers on PET Substrate by Roll-to-Roll Sputtering.

    Science.gov (United States)

    Kim, Taehoon; Park, Kwangwon; Kim, Jongsu

    2016-02-01

    Indium-free Al and Ga-codoped ZnO (AGZO) multilayer films with nanoscale Ag interlayer were deposited by dual target roll-to-roll RF for AGZO and DC sputtering systems for Ag at room temperature for a large scale. The thicknesses of AGZO/Ag/AGZO multilayer were optimized by changing the roll speed: 0.15/1.1/0.15 m/min for AGZO/Ag/AGZO multilayers, respectively. The optimum thicknesses of AGZO/Ag/AGZO multilayer are 9.21, 8.32 and 8.04 nm, respectively. Optimized AGZO/Ag/AGZO multilayer films showed an excellent transparency (84% at 550 nm) and a low sheet resistance (9.2 omega/sq.) on PET substrates for opto-electronic applications. The effects of nanoscale Ag interlayer on optical and electrical properties of AGZO/Ag/AGZO multilayer films were discussed.

  20. Fabrication and characterization of spark plasma sintered Ce:LuAG ceramic for scintillation application

    Science.gov (United States)

    Kumar, S. Arun; Senthilselvan, J.

    2016-05-01

    Rare earth Cerium doped Lutetium Aluminum Garnet (Ce:LuAG) ceramics are widely used as phosphor material in medical imaging and high-energy physics. Due to its technological importance, an attempt has been made to fabricate Ce:LuAG ceramics by using spark plasma sintering (SPS) technique. XRD patterns of SPS sintered Ce:LuAG ceramics reveals a mixed LuAG and CeO2 (antisite defect) phases. The microstructures of SPS sintered Ce:LuAG ceramics shows limited densification, inappropriate compaction of particles and existence of residual pores, voids between the grain boundaries affects the transparency of Ce:LuAG ceramics. Relative density and hardness of post sintered Ce:LuAG ceramic is also determined. The effect of Ce3+ doping concentration and sintering temperature on optical luminescence behavior of Ce:LuAG ceramic is presented.

  1. Tunable Visible Emission of Ag-Doped CdZnS Alloy Quantum Dots

    Directory of Open Access Journals (Sweden)

    Sethi Ruchi

    2009-01-01

    Full Text Available Abstract Highly luminescent Ag-ion-doped Cd1−xZnxS (0 ≤ x ≤ 1 alloy nanocrystals were successfully synthesized by a novel wet chemical precipitation method. Influence of dopant concentration and the Zn/Cd stoichiometric variations in doped alloy nanocrystals have been investigated. The samples were characterized by X-ray diffraction (XRD and high resolution transmission electron microscope (HRTEM to investigate the size and structure of the as prepared nanocrystals. A shift in LO phonon modes from micro-Raman investigations and the elemental analysis from the energy dispersive X-ray analysis (EDAX confirms the stoichiometry of the final product. The average crystallite size was found increasing from 1.0 to 1.4 nm with gradual increase in Ag doping. It was observed that photoluminescence (PL intensity corresponding to Ag impurity (570 nm, relative to the other two bands 480 and 520 nm that originates due to native defects, enhanced and showed slight red shift with increasing silver doping. In addition, decrease in the band gap energy of the doped nanocrystals indicates that the introduction of dopant ion in the host material influence the particle size of the nanocrystals. The composition dependent bandgap engineering in CdZnS:Ag was achieved to attain the deliberate color tunability and demonstrated successfully, which are potentially important for white light generation.

  2. Nitrogen- Doped Graphene Quantum Dots: "Turn-off" Fluorescent Probe for Detection of Ag(+) Ions.

    Science.gov (United States)

    Tabaraki, Reza; Nateghi, Ashraf

    2016-01-01

    Highly luminescent nitrogen-doped graphene quantum dots (N-GQDs) were prepared from glucose and ammonia as carbon and nitrogen sources, respectively. The N-GQDs showed a strong emission at 458 nm with excitation at 360 nm. The N-GQDs exhibited analytical potential as sensing probes for silver ions determination. Factors affecting the fluorescence sensing of Ag(+) ions such as pH, N-GQDs concentration and incubation time were studied using Box-Behnken experimental design. The optimum conditions were determined as pH 7, N-GQDs concentration 1 mg/mL and time 60 min. It suggested that N-GQDs exhibited high sensitivity and selectivity toward Ag(+). The linear range of N-GQDs and the limit of detection (LOD) were 0.2-40 μM and 168 nM, respectively. The N-GQDs-based Ag(+) ions sensor was successfully applied to the determination of Ag(+) in tap water and real river water samples.

  3. Controlled growth of standing Ag nanorod arrays on bare Si substrate using glancing angle deposition for self-cleaning applications

    Science.gov (United States)

    Singh, Dhruv P.; Singh, J. P.

    2014-03-01

    A facile approach to manipulate the hydrophobicity of surface by controlled growth of standing Ag nanorod arrays is presented. Instead of following the complicated conventional method of the template-assisted growth, the morphology or particularly average diameter and number density (nanorods cm-2) of nanorods were controlled on bare Si substrate by simply varying the deposition rate during glancing angle deposition. The contact angle measurements showed that the evolution of Ag nanorods reduces the surface energy and makes an increment in the apparent water contact angle compared to the plain Ag thin film. The contact angle was found to increase for the Ag nanorod samples grown at lower deposition rates. Interestingly, the morphology of the nanorod arrays grown at very low deposition rate (1.2 Å sec-1) results in a self-cleaning superhydrophobic surface of contact angle about 157° and a small roll-off angle about 5°. The observed improvement in hydrophobicity with change in the morphology of nanorod arrays is explained as the effect of reduction in solid fraction within the framework of Cassie-Baxter model. These self-cleaning Ag nanorod arrays could have a significant impact in wide range of applications such as anti-icing coatings, sensors and solar panels.

  4. Synthesis and Characterisation of Silver(I)-Bioglues and Assessment of Biological Activity of AgNO3 Against Staphylococcus aureus

    OpenAIRE

    Smith, Alanna

    2012-01-01

    Bioglue samples prepared in the absence and in the presence of Ag(I) ions (using AgNO3 and [Ag2(3,6,9-tdda)].2H2O (tddaH2 = trioxaundecanedioic acid)) were thermally stable and had the ability to swell in the presence of water. Generally, for the Ag(I)-Bioglues, as the amount of added Ag(I) ions decreased the degree of swelling increased. The surface morphology of the Bioglue without Ag(I) ions was very porous in comparison to the smooth surface of the Ag(I)-Bioglues. In tests using wood and ...

  5. Maps showing distribution of copper, lead, zinc, cadmium, and silver in samples of minus-60-mesh (0.25-MM) stream sediment and nonmagnetic heavy-mineral concentrate, Walker Lake 1 degree by 2 degrees Quadrangle, California and Nevada

    Science.gov (United States)

    Chaffee, M.A.; Hill, R.H.; Sutley, S.J.

    1988-01-01

    This report is part of a folio of maps of the Walker Lake 1o x 2o quadrangle, California and Nevada, prepared under the Conterminous United States Mineral Assessment Program. The folio includes geological, geochemical, and geophysical maps, as well as mineral resources assessment maps, which identify selected known or possible mineral-deposit environments in the quadrangle. The geochemical maps show the distributions of selected individual elements (Chaffee and others, 1988 a, b, c) and the distributions of selected groups of elements (Chaffee, 1988a, b, c). Discussions accompanying the individual element maps are restricted to mineral residences of the individual elements as well as to what types of mineral deposits and environments may be represented by anomalies of a particular element. Discussions accompanying the multielemental maps describe the types of mineral deposits that may be related to each element group and indicate the most favorable localities for these deposits. 

  6. Study on Synthesis and Antibacterial Properties of Ag NPs/GO Nanocomposites

    Directory of Open Access Journals (Sweden)

    Lei Huang

    2016-01-01

    Full Text Available Using graphene oxide as substrate and stabilizer for the silver nanoparticles, silver nanoparticles-graphene oxide (Ag NPs/GO composites with different Ag loading were synthesized through a facile solution-phase method. During the synthesis process, AgNO3 on GO matrix was directly reduced by NaBH4. The structure characterization was studied through X-ray diffraction (XRD, atomic force microscopy (AFM, high-resolution transmission electron microscope (HRTEM, ultraviolet-visible spectroscopy (UV-Vis, and selected area electron diffraction (SAED. The results show that Ag nanoparticles (Ag NPs with the sizes ranging from 5 to 20 nm are highly dispersed on the surfaces of GO sheets. The shape and size of the Ag NPs are decided by the volume of initial AgNO3 solution added in the GO. The antibacterial activities of Ag NPs/GO nanocomposites were investigated and the result shows that all the produced composites exhibit good antibacterial activities against Gram-negative (G− bacterial strain Escherichia coli (E. coli and Gram-positive (G+ strain Staphylococcus aureus (S. aureus. Moreover, the antibacterial activities of Ag NPs/GO nanocomposites gradually increased with the increasing of volume of initial AgNO3 solution added in the GO and this improvement of the antibacterial activities results from the combined action of size effect and concentration effect of Ag NPs in Ag NPs/GO nanocomposites.

  7. Ag recovery from copper anode slime by acid leaching at atmospheric pressure to synthesize silver nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Atefeh Khaleghi; Sattar Ghader; Dariush Afzali

    2014-01-01

    In this paper, recovery of silver from anode slime of Sarcheshmeh copper complex in Iran and subsequent synthesis of silver nanoparticles from leaching solution is investigated. Sarcheshmeh anode slime is mainly consisted of Cu, Ag, Pb and Se. Amount of Ag in the considered anode slime was 5.4%(by weight). The goal was to recover as much as possible Ag from anode slime at atmospheric pressure to synthesize Ag nanoparticles. Therefore, acid leaching was used for this purpose. The anode slime was leached with sulfuric and nitric acid from room to 90 ?C at different acid concentrations and the run which yielded the most recovery of Ag was selected for Ag nanoparticles synthesis. At this condition, Cu, Pb and Se are lea-ched as well as Ag. To separate Ag from leach solution HCl was added and silver was precipitated as AgCl which were then dissolved by ammonia solution. The Ag nanoparticles are synthesized from this solution by chemical reduction method by aid of sodium borohydride in the presence of PVP and PEG as stabiliz-ers. The synthesized Ag nanoparticles showed a peak of 394 nm in UV-vis spectrum and TEM images showed a rather uniform Ag nanoparticles of 12 nm.

  8. Growth Mechanism of Vertically Aligned Ag(TCNQ) Nanowires

    Institute of Scientific and Technical Information of China (English)

    叶春暖; 曹冠英; 莫晓亮; 方方; 邢晓艳; 陈国荣; 孙大林

    2004-01-01

    Highly oriented Ag(TCNQ) nanowires have been prepared on Si(111) wafer at 100 ℃ by the vapour-transport reaction between silver and TCNQ without any other catalyst. X-ray diffraction analysis shows that the composition and crystal structure of the obtained nanostructure were Ag(TCNQ) crystalline. Most Ag(TCNQ) nanowires were grown uniformly and vertically on the substrate with diameters ranging from 50 to 300nm and the lengths measuring from 2 to 50 μm by scanning electron microscopy. Ag particles were observed on the substrate from pure thin Ag film heated under the same conditions as used in synthesizing the nanowires. Nucleation and short Ag(TCNQ) nanowires were prepared by controlling the reaction time, providing direct evidence of the growth mechanism in a nanometre scale. The growth process was explained according to the vapour-liquid-solid model.The gradient of temperature and the densely distributed Ag particles may contribute to the vertically aligned growth. These results will be helpful for the controllable synthesis of Ag(TCNQ) nanowires.

  9. Voestalpine AG : equity valuation

    OpenAIRE

    Shamuradov, Rustam

    2014-01-01

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

  10. Equity valuation Siemens AG

    OpenAIRE

    Silva, Bernardo Santos

    2015-01-01

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

  11. AG mod rovet

    DEFF Research Database (Denmark)

    Storm, Rasmus K.

    2010-01-01

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

  12. Chromatographic analysis of phytochemicals components present in mangifera indica leaves for the synthesis of silver nanoparticles by AgNO3 reduction

    Science.gov (United States)

    Martínez-Bernett, D.; Silva-Granados, A.; Correa-Torres, S. N.; Herrera, A.

    2016-02-01

    It was studied the green synthesis of silver nanoparticles (AgNPs) from the reduction of a silver nitrate solution (1 and 10mM) in the presence of an extract of mangifera indica leaves. Phytochemicals components present in extracts of mango leaves were determined using a GC-MS chromatograph. The results showed the presence of the phenolic compound pyrogallol (26.9% wt/5mL of extract) and oleic acid (29.1% wt/5mL of extract), which are useful for the reduction of the metallic salt AgNO3 and the stabilization of silver nanoparticles. The synthesized nanoparticles were characterized by UV visible spectroscopy (UV-vis), evidencing absorbances at wavelengths of 417nm (AgNPs-1) and 414nm (AgNPs- 10), which are characteristic peaks of this metallic nanoparticles. Scanning Electron Microscopy (SEM) was used to determine the size of the synthesized nanoparticles. A particle size of about 28±7nm was observed for the AgNPs-1 sample and 26±5nm for the AgNPs-10. This suggests the advantages of green chemistry to obtain silver nanoparticles with a narrow size distribution.

  13. Effect of Graphene Nanoplatelets on Wetting, Microstructure, and Tensile Characteristics of Sn-3.0Ag-0.5Cu (SAC) Alloy

    Science.gov (United States)

    Sharma, Ashutosh; Sohn, Heung-Rak; Jung, Jae Pil

    2016-01-01

    The effect of graphene nanoplatelets (GNPs) on the wettability, microstructure, and tensile properties of Sn-3.0Ag-0.5Cu (SAC 305) was studied using melting and casting route. The microstructure of the bulk solder is observed with a scanning electron microscope and transmission electron microscope, and the intermetallic compound (IMC) phases are identified by electron probe micro-analyzer. The solderability of the samples is assessed by spreading and wetting tests on a Cu substrate. The experimental results indicate that an addition of 0.05 wt pct GNPs in Sn-3Ag-0.5Cu solder improves the spreading and wettability significantly compared to monolithic SAC. It is also revealed that the thickness of the Ag3Sn IMCs is reduced as compared to the monolithic SAC alloy. Tensile results show that the composite solder exhibits the 13.9 pct elongation and 17 pct increase in the ultimate tensile strength when 0.05 wt pct GNPs in Sn-3Ag-0.5Cu alloy are added. This may be due to the refinement of the IMCs in composite solders compared to the same in Sn-3Ag-0.5Cu alloy brought about by the uniform dispersion of graphene nanoplatelets. It is suggested in this study that the amount of GNPs in Sn-3Ag-0.5Cu alloy should not exceed 0.05 wt pct as it may degrade the desired properties due to the agglomeration of GNPs.

  14. Assessing the Effect of PVP of Various Molecular Weight (MW in PES-Ag Membranes: Antimicrobial Study Using E.Coli

    Directory of Open Access Journals (Sweden)

    Hatijah Basri

    2011-12-01

    Full Text Available New polymeric silver (Ag composites were prepared using polyethersulfone (PES as polymer material, N-Methyl-2-pyrrolidone (NMP as solvent and polyvinylpyrollidone (PVP of various molecular weight (MW as organic fillers. Silver nitrate (AgNO3 was added by various loading in order to impart an antibacterial property to the composites. The miscibility of PES/Ag/fillers composites were characterized using TGA and any changes in chemical bonding were characterized using ATR-FTIR techniques. The XPS results showed high intensity in Eb(Ag3d range of 378.1-378.5 and 372.2-372.5 for the highest Ag loading with PVP with the highest MW. This phenomenon had altered the hydrophilicity property of composites. In this study, composites have undergone a bacteria rejection test from E.coli suspension and a domestic waste sample. Composites with highest loading of silver and highest MW of PVP (PES-Ag2P360 was observed for significantly high bacteria rejection, log reduction value (LRV~3. Therefore, PES-silver nanocomposites is a potential membrane for bacteria removal, disinfection and maybe effective for overcoming biofouling problems.

  15. 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.

  16. 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.

  17. Thermal Annealing Effect on Structural, Morphological, and Sensor Performance of PANI-Ag-Fe Based Electrochemical E. coli Sensor for Environmental Monitoring

    Directory of Open Access Journals (Sweden)

    Norshafadzila Mohammad Naim

    2015-01-01

    Full Text Available PANI-Ag-Fe nanocomposite thin films based electrochemical E. coli sensor was developed with thermal annealing. PANI-Ag-Fe nanocomposite thin films were prepared by oxidative polymerization of aniline and the reduction process of Ag-Fe bimetallic compound with the presence of nitric acid and PVA. The films were deposited on glass substrate using spin-coating technique before they were annealed at 300°C. The films were characterized using XRD, UV-Vis spectroscopy, and FESEM to study the structural and morphological properties. The electrochemical sensor performance was conducted using I-V measurement electrochemical impedance spectroscopy (EIS. The sensitivity upon the presence of E. coli was measured in clean water and E. coli solution. From XRD analysis, the crystallite sizes were found to become larger for the samples after annealing. UV-Vis absorption bands for samples before and after annealing show maximum absorbance peaks at around 422 nm–424 nm and 426 nm–464 nm, respectively. FESEM images show the diameter size for nanospherical Ag-Fe alloy particles increases after annealing. The sensor performance of PANI-Ag-Fe nanocomposite thin films upon E. coli cells in liquid medium indicates the sensitivity increases after annealing.

  18. Oscillatory exchange coupling and strong direct tunnelling with AgCl based heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Vlaic, P., E-mail: vlaic_pc@yahoo.com [Faculty of Physics, Babes-Bolyai University, 400084 Cluj-Napoca (Romania); University of Medicine and Pharmacy “Iuliu Hatieganu”, Biophysics Department, 400023 Cluj-Napoca (Romania); Burzo, E. [Faculty of Physics, Babes-Bolyai University, 400084 Cluj-Napoca (Romania); Carva, K. [Department of Condensed Matter Physics, Charles University in Prague, Faculty of Mathematics and Physics, Ke Karlovu 5, CZ-12116 Prague 2 (Czech Republic)

    2015-05-05

    Highlights: • Structural and electronic properties of Fe/AgCl/Fe (0 0 1) junctions are studied. • Total energy calculations show that Fe/AgCl/Fe (0 0 1) heterostructures are stable. • The exchange coupling across AgCl spacer shows unexpected oscillations. • Strong direct tunnelling of Δ{sub 1} states across AgCl barrier is evidenced. • High tunnelling magnetoresistance ratios are predicted. - Abstract: The structural stability and ground state electronic properties of Fe/AgCl/Fe (0 0 1) junctions with c(2 × 2) Fe/AgCl (0 0 1) heterointerfaces are studied by means of ab initio surface Green’s function technique for surface and interfaces. The spin-resolved ballistic conductances across Fe/AgCl/Fe (0 0 1) heterojunctions are determined by using Kubo–Landauer approach. Total energy calculations show that sharp Fe/AgCl (0 0 1) interfaces are possible. The interfacial charge transfer is interface sensitive and generates electrostatic interactions that contribute to the stabilization of Fe/AgCl (0 0 1) interfaces. The magnetism of interfacial Fe layers is robust but is responsive to the interfacial structure. The exchange coupling between Fe electrodes across AgCl barriers shows unexpected oscillations with respect to the spacer thickness that may be related in part with the amount of metal induced gap states in AgCl spacers. A powerful Δ{sub 1} spin filter effect is evidenced across AgCl barriers. Depending on the interface structure, large magnetoresistance ratios, above 3100%, are predicted. Interfacial interdiffusion may affect the magnetoresistive properties. The lower lattice mismatch at c(2 × 2) Fe/AgCl (0 0 1) interfaces combined with the strong Δ{sub 1} direct tunnelling across AgCl barriers make Fe/AgCl (0 0 1) interfaces attractive in the context of magnetoelectronics.

  19. Thermopower of YBa2Cu3O7-δ-Ag composites

    International Nuclear Information System (INIS)

    This paper reports on the percolation behavior of normal-state thermopower, resistivity, and superconductivity that have been studied in YBa2Cu3O7-δ-Ag (YBCO-Ag) composite systems. The normal-state resistivity and thermopower show a percolation threshold at a Ag volume fraction (VAg) of 20% to 30%, whereas the superconducting network shows a threshold at a VAg of ∼70% to 80%. The results obtained from this study show that the YBCO-Ag composite obtained from Ag2O and YBCO powders is uniformly distributed with Ag and YBCO remaining as separate phases without changing their characteristics. The measurements of thermopower indicate that the normal-state thermopower and phonon-drag thermopower are affected by the Ag addition. The stability of YBCO is increased when it is in composite form

  20. Atomic mechanisms of. gamma. ' precipitate plate growth in the Al-Ag system

    Energy Technology Data Exchange (ETDEWEB)

    Howe, J.M.

    1985-03-01

    Energy-dispersive x-ray spectroscopy results that the precipitates have the composition Ag/sub 2/Al. High-resolution electron microscopy of ..gamma..' precipitates in both <110>//<1120> and <111>//<0001> orientations shows that all interfaces of the precipitate are largely coherent with the matrix and are faceted along low-energy (111) and (110) matrix plans, due to the influence of surface and elastic strain energies on the transformation. Further comparison between experimental and calculated high-resolution images of the precipitate/matrix interface and of Shockley partial dislocation ledges on the precipitate faces demonstrates that both thickening and lengthening of ..gamma..' precipitate plates occurs by the passage of the Shockley partial dislocations along alternate (111) matrix planes by a terrace-ledge-kink mechanism. These images and electron diffraction information also indicate that the ..gamma..' precipitates are ordered, where the A-planes in the precipitate contain nearly pure Ag and the B-planes have the composition Al/sub 2/Ag, and that the limiting reaction in the growth process is the substitutional diffusion of Ag cross kinks in the Shockley partial dislocations, which terminate in the Ag-rich A-planes. The terraces between ledges are atomically flat and ledges are uniformly stepped-down from the centers to the edges of isolated precipitates. Convergent-beam electron diffraction (CBED) analyses of ..gamma..' precipitates indicate that they have the space group P6/sub 3//mmc. Effect of specimen thickness on symmetry determinations by CBED was also examined for an ..cap alpha..-titanium sample. Results show that the symmetries observed in CBED patterns from thin specimens may be due to the limited thickness of the specimen, rather than to the actual space group of the material.

  1. Atomic mechanisms of γ' precipitate plate growth in the Al-Ag system

    International Nuclear Information System (INIS)

    Energy-dispersive x-ray spectroscopy results that the precipitates have the composition Ag2Al. High-resolution electron microscopy of γ' precipitates in both // and // orientations shows that all interfaces of the precipitate are largely coherent with the matrix and are faceted along low-energy (111) and (110) matrix plans, due to the influence of surface and elastic strain energies on the transformation. Further comparison between experimental and calculated high-resolution images of the precipitate/matrix interface and of Shockley partial dislocation ledges on the precipitate faces demonstrates that both thickening and lengthening of γ' precipitate plates occurs by the passage of the Shockley partial dislocations along alternate (111) matrix planes by a terrace-ledge-kink mechanism. These images and electron diffraction information also indicate that the γ' precipitates are ordered, where the A-planes in the precipitate contain nearly pure Ag and the B-planes have the composition Al2Ag, and that the limiting reaction in the growth process is the substitutional diffusion of Ag cross kinks in the Shockley partial dislocations, which terminate in the Ag-rich A-planes. The terraces between ledges are atomically flat and ledges are uniformly stepped-down from the centers to the edges of isolated precipitates. Convergent-beam electron diffraction (CBED) analyses of γ' precipitates indicate that they have the space group P63/mmc. Effect of specimen thickness on symmetry determinations by CBED was also examined for an α-titanium sample. Results show that the symmetries observed in CBED patterns from thin specimens may be due to the limited thickness of the specimen, rather than to the actual space group of the material

  2. Posintro™-HBsAg, a modified ISCOM including HBsAg, induces strong cellular and humoral responses

    DEFF Research Database (Denmark)

    Schiött, Asa; Larsson, Kristina; Manniche, Søren;

    2011-01-01

    To improve the hepatitis B vaccines on the market new adjuvant systems have to substitute aluminium. In this study the hepatitis B surface antigen (HBsAg) was incorporated into a novel adjuvant system, the Posintro™, a modification of the traditional immune stimulatory complexes (ISCOMs). This new...... HBsAg vaccine formulation, Posintro™-HBsAg, was compared to two commercial hepatitis B vaccines including aluminium or monophosphoryl lipid A (MPL) and the two adjuvant systems MF59 and QS21 in their efficiency to prime both cellular and humoral immune responses. The Posintro™-HBsAg induced....... The results demonstrate that this novel experimental vaccine formulation, the Posintro™-HBsAg, is strongly immunogenic and can induce both class I and class II responses in experimental animals. This shows promise both for the protection against hepatitis B virus infection and as a potential therapeutic...

  3. A Holographic Road Show.

    Science.gov (United States)

    Kirkpatrick, Larry D.; Rugheimer, Mac

    1979-01-01

    Describes the viewing sessions and the holograms of a holographic road show. The traveling exhibits, believed to stimulate interest in physics, include a wide variety of holograms and demonstrate several physical principles. (GA)

  4. Photoelectron spectroscopy study of thin Ag films deposited on to amorphous In–Ga–Zn–O surface

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Se Jun [Department of Physics, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Baik, Jaeyoon; Ha, Taekyun; Park, Chong Do [Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Shin, Hyun-Joon, E-mail: shj001@postech.ac.kr [Department of Physics, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Chung, JaeGwan; Lee, Jaecheol [A E Group, Samsung Advanced Institute of Technology, Giheung-Gu, Yongin-Si, GyeingGi-Do 449-712 (Korea, Republic of)

    2014-11-03

    Ag was thermally evaporated onto amorphous In–Ga–Zn–O (a-IGZO) thin film, and the Ag-thickness (< 0.3 nm)-dependent chemical states of the Ag-deposited a-IGZO thin-film surfaces were investigated by high-resolution X-ray photoelectron spectroscopy. As Ag layer thickness increased, Ag 3d shifted towards the lower binding energy (BE) side and In 3d developed a lower-BE component; however, O 1s, Ga 3d, and Zn 3d showed much smaller spectral feature changes than Ag 3d or In 3d. The analysis suggests that Ag atoms preferentially interact and share electrons with In atoms. The Ag 4d split feature at the valence band and the metallic states near the Fermi edge were noticeably visible when the Ag thickness was greater than 0.1 nm. - Highlights: • Ag was deposited on a-IGZO thin film using thermal evaporation method. • Chemical state changes of Ag-deposited a-IGZO were investigated by XPS. • As Ag layer thickness increased, In 3d developed a lower-BE component. • As Ag layer thickness increased, Ag 3d shifted towards the lower BE side. • Ag atoms preferentially interact and share electrons with In atoms.

  5. Ag-TiO2纳米棒阵列的抗菌性和光催化性能研究%Antibacterial and Photocatalytic Properties of Ag-TiO2 Nanorod Arrays

    Institute of Scientific and Technical Information of China (English)

    李萌; 贺晓静; 王会珍; 杭瑞强; 黄晓波; 张翔宇; 唐宾

    2016-01-01

    目的:制备一种高抗菌性和高光催化活性的Ag掺杂TiO2(Ag-TiO2)纳米棒阵列。方法通过磁控溅射与水热复合处理法,在钛箔片表面制备出Ag掺杂TiO2(Ag-TiO2)纳米棒阵列,酸化处理过的试样在500℃下煅烧2 h。采用X射线衍射(XRD)进行物相分析,利用场发射扫描电子显微镜(SEM)、场发射透射电子显微镜(TEM)、能量分散谱仪(EDS)观察试样的表面、截面形貌、微观结构和组成,并探究其对大肠杆菌和金黄色葡萄球菌的杀菌性能和对亚甲基蓝的光催化降解能力。结果该工艺下制备的 Ag-TiO2纳米棒大小均匀,取向明显,主要由锐钛矿型 TiO2相组成。Ag-TiO2纳米棒对大肠杆菌和金黄色葡萄球菌具有优异的杀菌效果,杀菌率几乎达到100%。Ag-TiO2纳米棒能有效地提高亚甲基蓝的降解率。结论磁控溅射与水热复合处理法在钛箔片表面成功制备出Ag-TiO2纳米棒阵列,此阵列具有优异的杀菌能力、高抗菌和光催化降解性能。%Objective To prepare Ag-TiO2 nanorod arrays with excellent antibacterial activity and photocatalytic perfor-mance.Methods The Ag-TiO2 nanorod arrays were synthesized directly on Ti foils by magnetron sputtering and hydrothermal treatment method. The acid treated sample was calcined at 500 degrees for 2 hours. The phase composition of the synthesized samples was analyzed by X-ray diffraction (XRD), Surface cross sectional morphology microstructure and chemical elements were observed by scanning electron Microscope (SEM), transmission electron microscope (TEM) and Energy Dispersive Spec- troscopy(EDS). The photocatalytic antibacterial performance after contact with S. aureus and E. coli was assessed. And the pho-tocatalytic degradation of methylene blue was measured under visible light.ResultsThe results showed that the anatase TiO2 phase nanorods had uniform size and obvious orientation. The Ag-TiO2 nanorod arrays

  6. Ionic Conductivity and Phase Transition Behaviour in 4AgI-(1-PbI2-2CuI System

    Directory of Open Access Journals (Sweden)

    Mohammed Hassan

    2008-01-01

    Full Text Available Samples of general formula 4AgI-(1-PbI2-2CuI, =0-0.4, have been prepared and investigated by XRD, DSC, and temperature-dependent conductivity studies. X-ray diffractograms showed the presence of binary system consisting of AgI and PbI2 in the sample =0. Cu-substituted samples showed very similar diffractograms to that of the pure compound which indicates that no effect for the substitution on the nature of the binary system. DSC curves showed the presence of phase transition whose temperature increased with Cu+ ratio in the system. Ionic conductivity measurements confirmed the occurrence of the phase transition and showed that the high temperature phase is superionic conducting, whose conductivity increases with the increasing Cu+ amount in the system.

  7. 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.

  8. Polypyrrole microspheroidals decorated with Ag nanostructure: Synthesis and their characterization

    International Nuclear Information System (INIS)

    In this work, polypyrrole (PPy) microspheroidals were synthesized by chronopotentiometry on conducting indium tin oxide (ITO) substrate. These prepared PPy microspheroidals were subjected to surface modification by Ag nanostructures using cyclic voltammetery (CV). The decoration of Ag nanostructures on PPy surface was characterized by UV–visible spectroscopy (UV–vis), X-ray diffraction (XRD), Fourier transform infrared (FTIR), energy dispersion X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). SEM images show nanostar like structures with slight aggregation of Ag nanostructures on the PPy surface. The average particle size of PPy was found to increase from 7.3 to 30 nm after decoration with Ag nanostructure. Further, the XRD patterns shows a decrease in interchain separation and inter planar distance after the impregnation of Ag nanostructures in the PPy film when compared with pure PPy film. FTIR and Raman spectra displayed main vibrational bands; including the characteristic peaks. Raman spectra also show the signature of polaron and bipolaron states. Electrical conductivity of the Ag nanostructure decorated PPy microspheroidals has been measured by the two probe method. A possible mechanism for the formation of Ag-PPy nanostructure has been proposed.

  9. 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.

  10. 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.

  11. Show-Bix &

    DEFF Research Database (Denmark)

    2014-01-01

    made from digital scans of the original dias slides located in the collection of the Museum of Contemporary Art in Roskilde. In front of the audience entering the space and placed on it’s own stand, is an original 60s style telephone with turning dial. Action begins when the audience lift the phone and......The anti-reenactment 'Show-Bix &' consists of 5 dias projectors, a dial phone, quintophonic sound, and interactive elements. A responsive interface will enable the Dias projectors to show copies of original dias slides from the Show-Bix piece ”March på Stedet”, 265 images in total. The copies are...... dial a number. Any number will make the Dias change. All numbers are also assigned to specific sound documents: clips form rare interviews and the complete sound-re-enactment of the Show-Bix piece ‘Omringning’ (‘Surrounding’) in five channels (a quintophonie). This was originally produced in...

  12. Honored Teacher Shows Commitment.

    Science.gov (United States)

    Ratte, Kathy

    1987-01-01

    Part of the acceptance speech of the 1985 National Council for the Social Studies Teacher of the Year, this article describes the censorship experience of this honored social studies teacher. The incident involved the showing of a videotape version of the feature film entitled "The Seduction of Joe Tynan." (JDH)

  13. A Visionary Show

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Seduction. Distinction. Relax. Pulsation. These are the "style universes" on display at Première Vision, heralded as "The World’s Premiere Fabric Show." Started more than 35 years ago by 15 French weavers, Première Vision has expanded beyond its

  14. Violence and TV Shows

    OpenAIRE

    ÖZTÜRK, Yrd. Doç. Dr. Şinasi

    2008-01-01

    This study aims to discuss theories on theviolent effects of TV shows on viewers, especiallyon children. Therefore, this study includes a briefdiscussion of definitions of violence, discussionof violence theories, main results of researcheson televised violence, measuring TV violence,perception of televised violence, individualdifferences and reactions to TV violence,aggressiveness and preferences for TV violence.

  15. Obesity in show cats.

    Science.gov (United States)

    Corbee, R J

    2014-12-01

    Obesity is an important disease with a high prevalence in cats. Because obesity is related to several other diseases, it is important to identify the population at risk. Several risk factors for obesity have been described in the literature. A higher incidence of obesity in certain cat breeds has been suggested. The aim of this study was to determine whether obesity occurs more often in certain breeds. The second aim was to relate the increased prevalence of obesity in certain breeds to the official standards of that breed. To this end, 268 cats of 22 different breeds investigated by determining their body condition score (BCS) on a nine-point scale by inspection and palpation, at two different cat shows. Overall, 45.5% of the show cats had a BCS > 5, and 4.5% of the show cats had a BCS > 7. There were significant differences between breeds, which could be related to the breed standards. Most overweight and obese cats were in the neutered group. It warrants firm discussions with breeders and cat show judges to come to different interpretations of the standards in order to prevent overweight conditions in certain breeds from being the standard of beauty. Neutering predisposes for obesity and requires early nutritional intervention to prevent obese conditions. PMID:24612018

  16. Characterization of AZO and Ag based films prepared by RF magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Dagang [Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong (China); Jiang, Shouxiang, E-mail: kinor.j@polyu.edu.hk [Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong (China); Zhao, Hongmei [Department of Prosthodontics, The Affiliated Hospital of Qingdao University, Qingdao (China); Shang, Songmin; Chen, Zhuoming [Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong (China)

    2014-12-15

    Highlights: • Highly infrared reflective AZO and Ag based films were prepared. • Ag showed better crystallization on AZO film than on glass substrate. • Infrared reflection rate was inversely proportional to the film sheet resistance. • Film with infrared reflection of 97% in FIR region was acquired. - Abstract: Ag, AZO/Ag, Ag/AZO and AZO/Ag/AZO films were prepared on glass substrates by radio frequency (RF) magnetron sputtering technology. The prepared films were systematically investigated by X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), UV–visible spectrophotometer, a four-point probe system and Fourier Transform Infrared Spectroscopy. The results indicated that Ag inner layer starts forming a continuous film at the thickness of 10 nm and Ag layer presents superior crystallization on AZO substrate than that on glass substrate. The continuous Ag inner layer film provided the highest average visible transmittance of 85.4% (AZO/Ag/AZO). The lowest sheet resistance of 3.21 Ω/sq and the highest infrared reflection rate of 97% in FIR region can be obtained on AZO/Ag (15 nm)/AZO film. The high infrared reflection property of the AZO/Ag/AZO coating makes it a promising candidate for solar control films.

  17. Synthesis and characterization of Ag nanoparticles decorated mesoporous sintered activated carbon with antibacterial and adsorptive properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenxia; Xiao, Kaijun, E-mail: fekjxiao@scut.edu.cn; He, Tinglin; Zhu, Liang, E-mail: zhuliang@scut.edu.cn

    2015-10-25

    In this study, the sliver nanoparticles (AgNPs) immobilized on the sintered activated carbon (Ag/SAC) were synthesized by the ultrasonic-assisted impregnation method and were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and nitrogen adsorption. SEM showed that the AgNPs were well embedded in the SAC and immersion time had an important influence on final morphologies of AgNPs. Longer immersing duration caused significant aggregation of the AgNPs. The XRD data revealed that the successful synthesis of AgNPs on the SAC and immobilizing AgNPs on sintered active carbon did not change the crystalline degree of SAC. Texture characteristics were determined by analysis of the N{sub 2}/77 K isotherms. The minimum inhibitory concentration (MIC) of Ag/SAC against Escherichia coli (DH5α) and Staphyloccocus aureus (ATCC 29213) was evaluated by a broth dilution method. MICs such as 5 mg/L (against E. coli) and 10 mg/L (against S. aureus) suggest that Ag/SAC have predominant antibacterial activity compared to active carbon. - Highlights: • Sintered active carbon (SAC) was coated with Ag via a facile approach. • The Ag/SAC exhibit good adsorption properties and excellent antibacterial effects. • The Ag/SAC was durable and stable in the application of water purification.

  18. The Optical Nonlinearity of Au and Ag Nanoparticle Prepared by the Γ-Radiation Method

    Directory of Open Access Journals (Sweden)

    Esmaeil Shahriari

    2010-01-01

    Full Text Available Problem statement: The third order nonlinear optical properties of metal nanoparticles have been of interest in physical chemistry, medical diagnostics and optical devices. Gold colloidal nanoparticles are responsible for the brilliant reds seen in stained glass windows and silver particles are typically yellow. The purpose of the study was to determine the nonlinear refraction and absorption coefficient of the Au and Ag nanoparticles in PVP solution. Approach: The samples were prepared by Γ-radiation method and the nonlinear optical properties of the composites were investigated using a single beam Z-scan technique with a beam power of 40 mW and operated at wavelength of 532 nm. The measurements were carried out for both Open and closed aperture Z-scan arrangements. Results: For both Au/PVP and Ag/PVP samples the results exhibited reverse saturable absorption. The closed aperture Z-scan of the nano-fluid samples revealed self-defocusing effect while the open aperture Z-scan of the samples show a reversible saturable absorption. Conclusion: The Z-scan measurement showed that silver and gold nano-fluid prepared by gamma radiation exhibited large thermal nonlinear refractive index n2 as -8.78×10-7 and -2.478×10-6 cm2/W, respectively. We have also investigated nonlinear absorption of these samples and we found a large value of nonlinear absorption for Ag nanoparticle and a weak absorption for Au nanoparticle. In conclusion, the experimental result shows a good nonlinear refractive index at low laser power in which encouraging for possible applications in nonlinear optical devices.

  19. Ag Nanoparticles (Ag NM300K in the Terrestrial Environment: Effects at Population and Cellular Level in Folsomia candida (Collembola

    Directory of Open Access Journals (Sweden)

    Luís André Mendes

    2015-10-01

    Full Text Available The effects of nanomaterials have been primarily assessed based on standard ecotoxicity guidelines. However, by adapting alternative measures the information gained could be enhanced considerably, e.g., studies should focus on more mechanistic approaches. Here, the environmental risk posed by the presence of silver nanoparticles (Ag NM300K in soil was investigated, anchoring population and cellular level effects, i.e., survival, reproduction (28 days and oxidative stress markers (0, 2, 4, 6, 10 days. The standard species Folsomia candida was used. Measured markers included catalase (CAT, glutathione reductase (GR, glutathione S-transferase (GST, total glutathione (TG, metallothionein (MT and lipid peroxidation (LPO. Results showed that AgNO3 was more toxic than AgNPs at the population level: reproduction EC20 and EC50 was ca. 2 and 4 times lower, respectively. At the cellular level Correspondence Analysis showed a clear separation between AgNO3 and AgNP throughout time. Results showed differences in the mechanisms, indicating a combined effect of released Ag+ (MT and GST and of AgNPs (CAT, GR, TG, LPO. Hence, clear advantages from mechanistic approaches are shown, but also that time is of importance when measuring such responses.

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

    Science.gov (United States)

    Huo, Pengyun; Rey-Stolle, Ignacio

    2016-06-01

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

  1. 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.

  2. Vancomycin-functionalised Ag-TiO{sub 2} phototoxicity for bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Wan Yi [Chinese Academy of Sciences, Key Lab of Corrosion Science, Shandong Province, Institute of Oceanology, 7 Nanhai Road, Qingdao 266071 (China); Zhang Dun, E-mail: zhangdun@ms.qdio.ac.cn [Chinese Academy of Sciences, Key Lab of Corrosion Science, Shandong Province, Institute of Oceanology, 7 Nanhai Road, Qingdao 266071 (China); Wang Yi; Qi Peng; Wu Jiajia; Hou Baorong [Chinese Academy of Sciences, Key Lab of Corrosion Science, Shandong Province, Institute of Oceanology, 7 Nanhai Road, Qingdao 266071 (China)

    2011-02-15

    Research highlights: {yields} A multivalent interaction between Van-Ag-TiO{sub 2} and SRB. {yields} Van-Ag-TiO{sub 2} allow for selective photokilling of pathogen. {yields} Van-Ag-TiO{sub 2} show certain bactericidal property in dark. - Abstract: This study reports on the synthesis of vancomycin (Van)-functionalised Ag-TiO{sub 2} nanoparticles and their enhanced bactericidal activities. Van-Ag-TiO{sub 2} nanoparticles were prepared by nanoparticle deposition and chemical cross-linking reactions. The catalysts showed high efficiency for the degradation of methylene blue under ultraviolet (UV) illumination. The photocatalytic inactivation of the sulphate-reducing bacteria, Desulfotomaculum, was also studied under UV light irradiation and in the dark using aqueous mixtures of Ag, Ag-SiO{sub 2}, Ag-TiO{sub 2}, and Van-Ag-TiO{sub 2}. The Van-Ag-TiO{sub 2} nanoparticles showed a capacity to target Van-sensitive bacteria. They also effectively prevented bacterial cell growth through the functionalised nanoparticles under UV irradiation for 1 h. To investigate the specificity of the catalyst phototoxicity, a Van-resistant bacteria, Vibrio anguillarum, was used as the negative control. The results indicated that Van-Ag-TiO{sub 2} nanoparticles had a higher selective phototoxicity for Van-sensitive bacteria. Therefore, the antibiotic molecule-functionalised core-shell nanoparticles allow for selective photokilling of pathogenic bacteria.

  3. Nano-Ag complexes prepared by γ-radiolysis and their structures and physical properties

    International Nuclear Information System (INIS)

    In this study, nano-silver (nano-Ag) complexes showing different properties have been synthesized as follows. Polypyrrolidone (PVP)-stabilized silver colloids (NAg), nano-Ag bound to silica (SiO2) (NSS), and nano-Ag bound to a complex of SiO2 and polyaniline (PANI) (NSSPAI) were prepared via γ-irradiation at room temperature. NAg and NSS used PVP as a colloidal stabilizer, while NSSPAI did not use PVP as a colloidal stabilizer. Interesting bonding properties occurred in the nano-Ag complex and anticipated structural changes were clearly shown through a surface analysis of x-ray photoelectron spectroscopy (XPS). The morphologies by field emission-scanning electron microscopy (FE-SEM) analysis showed that nano-Ag complexes have various particle sizes ranging from 10 to 30 nm. NSS (average, 10 nm) and NSSPAI (average, 30 nm) showed a uniformly spherical shape and size, while NAg did not. From the reflection peaks in the x-ray diffraction (XRD) patterns, surface crystallinity of the nano-Ag complexes was indicated to be in the same degree as that of NSSPAI>NSS>NAg. Also, in the contact angle (CA) determination, surface hydrophobicity of NSSPAI was stronger than those of NSS and NAg, relatively. The different nano-Ag complexes prepared by γ-irradiation can be applicable in various industry fields due to the increase in specific property. - Highlights: ► Nano-Ag complexes showing different properties have been synthesized via γ-irradiation. ► Nano-Ag colloid (NAg), nano-Ag bound to SiO2 (NSS), nano-Ag bound to SiO2 and PANI complex (NSSPAI). ► Nano-Ag complexes were the same based on Ag metal. ► Results clearly showed fascinating/different physical properties. ► Different nano-Ag complexes can be applicable in various industry fields.

  4. The preparation and antibacterial effects of dopa-cotton/AgNPs

    Energy Technology Data Exchange (ETDEWEB)

    Xu Hong, E-mail: hxu@dhu.edu.cn [Key Lab of Science and Technology of Eco-textile, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Shi Xue; Ma Hui; Lv Yihang; Zhang Linping [Key Lab of Science and Technology of Eco-textile, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Mao Zhiping, E-mail: zhpmao@dhu.edu.cn [Key Lab of Science and Technology of Eco-textile, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China)

    2011-05-15

    Silver nanoparticles (AgNPs) have been known to have powerful antibacterial activity. In this paper, in situ generation of AgNPs on the surface of dopamine modified cotton fabrics (dopa-cotton/AgNPs) in aqueous solution under room temperature is presented. X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscope (FE-SEM) were used to analyze the surface chemical composition and the morphology of the modified cotton fabrics, respectively. The results indicated that the surface of cotton fabrics was successfully coated with polydopamine and AgNPs. The cotton fabrics with AgNPs showed durable antibacterial activity.

  5. Microstructure and tribological properties of NbN-Ag composite films by reactive magnetron sputtering

    Science.gov (United States)

    Ju, Hongbo; Xu, Junhua

    2015-11-01

    Recently, the chameleon thin films were developed with the purpose of adjusting their chemistry at self-mating interfaces in response to environmental changes at a wide temperature range. However, very few studies have focused on what state the lubricious noble metal exists in the films and the tribological properties at room temperature (RT). Composite NbN-Ag films with various Ag content (Ag/(Nb + Ag)) were deposited using reactive magnetron sputtering to investigate the crystal structure, mechanical and tribological properties. A combination of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM) analyses showed that face-centered cubic (fcc) NbN, hexagonal close-packed (hcp) NbN and fcc silver coexisted in NbN-Ag films. The incorporation of soft Ag into NbN matrix led to the hardness decrease from 29.6 GPa at 0 at.% Ag to 11.3 GPa at 19.9 at.% Ag. Tribological properties of NbN-Ag films performed using dry pin-on-disc wear tests against Al2O3 depended on Ag content to a large extent. The average friction coefficient and wear rate of NbN-Ag films decreased as Ag content increased from 4.0 to 9.2 at.%. With a further increase of Ag content, the average friction coefficient further decreased, while the wear rate increased gradually. The optimal Ag content was found to be 9.2-13.5 at.%, which showed low average friction coefficient values of 0.46-0.40 and wear rate values of 1.1 × 10-8 to 1.7 × 10-8 mm3/(mm N). 3D Profiler and Raman spectroscopy measurements revealed that the lubricant tribo-film AgNbO3 detected on the surface of the wear tracks could lead to the friction coefficient curve stay constant and decrease the average friction coefficients. The decrease of wear rate was mainly attributed to the lubricant tribo-film AgNbO3 as Ag content increased from 4.0 to 9.2 at.%; with a further increase in Ag content, the wear rate increased with increasing Ag content in NbN-Ag films because a

  6. Shanghai Shows Its Heart

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The city known as China’s economic powerhouse showed a more caring face as host of the Special Olympic Games Between October 2 and 11,the Special Olympics Summer Games were hosted in Shanghai,the first time the 40-year-old athletic com- petition for people with intellectual disabilities came to a developing country. This Special Olympics was also larger than all previous games in temps of the number of athletes.

  7. Dependence of SERS enhancement on the chemical composition and structure of Ag/Au hybrid nanoparticles.

    Science.gov (United States)

    Chaffin, Elise; O'Connor, Ryan T; Barr, James; Huang, Xiaohua; Wang, Yongmei

    2016-08-01

    Noble metal nanoparticles (NPs) such as silver (Ag) and gold (Au) have unique plasmonic properties that give rise to surface enhanced Raman scattering (SERS). Generally, Ag NPs have much stronger plasmonic properties and, hence, provide stronger SERS signals than Au NPs. However, Ag NPs lack the chemical stability and biocompatibility of comparable Au NPs and typically exhibit the most intense plasmonic resonance at wavelengths much shorter than the optimal spectral region for many biomedical applications. To overcome these issues, various experimental efforts have been devoted to the synthesis of Ag/Au hybrid NPs for the purpose of SERS detections. However, a complete understanding on how the SERS enhancement depends on the chemical composition and structure of these nanoparticles has not been achieved. In this study, Mie theory and the discrete dipole approximation have been used to calculate the plasmonic spectra and near-field electromagnetic enhancements of Ag/Au hybrid NPs. In particular, we discuss how the electromagnetic enhancement depends on the mole fraction of Au in Ag/Au alloy NPs and how one may use extinction spectra to distinguish between Ag/Au alloyed NPs and Ag-Au core-shell NPs. We also show that for incident laser wavelengths between ∼410 nm and 520 nm, Ag/Au alloyed NPs provide better electromagnetic enhancement than pure Ag, pure Au, or Ag-Au core-shell structured NPs. Finally, we show that silica-core Ag/Au alloy shelled NPs provide even better performance than pure Ag/Au alloy or pure solid Ag and pure solid Au NPs. The theoretical results presented will be beneficial to the experimental efforts in optimizing the design of Ag/Au hybrid NPs for SERS-based detection methods.

  8. Controlled formation of ag nanoparticles by means of long-chain sodium polyacrylates in dilute solution.

    Science.gov (United States)

    Huber, Klaus; Witte, Thomas; Hollmann, Jutta; Keuker-Baumann, Susanne

    2007-02-01

    A new tool is presented to control formation of Ag nanoparticles. Small amounts of silver ions were added to dilute solutions of long-chain sodium polyacrylates (NaPA). Four NaPA samples covering a molar mass regime of 97 kD polyacrylate coils toward compact structures. Coil shrinking and aggregation was revealed by means of time-resolved static light scattering. If exposed to UV-radiation, small Ag particles formed within the shrunken anionic polyacrylate coils. The Ag nanoparticles were identified by means of an enhanced light scattering and a characteristic plasmon absorption band around 410 nm. No such Ag particle formation could be observed even at 5 times larger concentrations of Ag(+) and NaPA if the two smallest polyacrylate samples have been used under otherwise equal conditions. This molar mass sensitive response of NaPA to Ag(+)-addition suggests an interesting phenomenon: if the coil size of the NaPa chains, which act as Ag(+) collectors, is large enough, local Ag(+) concentration in these coil-shaped Ag(+) containers exceeds a critical value, and irradiation with UV generates Ag nanoparticles. PMID:17263389

  9. SERS-active Ag, Au and Ag–Au alloy nanoparticles obtained by laser ablation in liquids for sensing methylene blue

    Energy Technology Data Exchange (ETDEWEB)

    Olea-Mejía, Oscar, E-mail: oleaoscar@yahoo.com.mx [Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Universidad Autónoma del Estado de México, km 14.5 Carretera Toluca-Atlacomulco, San Cayetano 50200, México (Mexico); Fernández-Mondragón, Mariana; Rodríguez-de la Concha, Gabriela [Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Universidad Autónoma del Estado de México, km 14.5 Carretera Toluca-Atlacomulco, San Cayetano 50200, México (Mexico); Camacho-López, Marco [Laboratorio de Investigación y Desarrollo de Materiales Avanzados, Universidad Autónoma del Estado de México, Km 14.5 Carretera Toluca-Atlacomulco, San Cayetano 50925, México (Mexico)

    2015-09-01

    Highlights: • We synthesized Ag/Au nanoparticles by laser ablation in liquids. • We characterized such particles by UV–vis, TEM and EDS/STEM. • The SERS effect was studied for the obtained nanoparticles. • Pure silver nanoparticles showed the highest SERS signals. • We can sense methylene blue at a concentration of 10{sup −10} mole/L. - Abstract: We have synthesized Ag–Au nanoparticles by laser ablation in liquids using five different targets: 100% Ag, 80%Ag/20%Au, 50%Ag/50%Au, 20%Ag/80%Au and 100% Au (weight percentages). We used ethanol and methylene blue solutions in ethanol as the liquid media. The nanoparticles were mostly spherical with diameters 15, 19, 18, 23 and 11 nm, respectively. When alloyed targets were used, the resulting nanoparticles were completely alloyed forming solid solutions as evidenced by UV–vis Spectroscopy and Scanning Transmission Electron Microscopy. The obtained nanoparticles were employed to study the SERS effect of the methylene blue molecule. All the samples showed good SERS activity, however the ones composed of pure silver showed the greatest Raman signal enhancement. Finally, pure Ag nanoparticles were used for sensing methylene blue at different concentrations. While almost no signal can be discerned from the Raman spectrum when no particles are used at a concentration of methylene blue of 1 × 10{sup −2} M (∼3000 ppm), when Ag nanoparticles are used one can observe the characteristic peak of the molecule at concentrations as low as 1 × 10{sup −10} M (∼3 × 10{sup −5} ppm)

  10. Effects of Ag + and Au 3+ ion implantation of lithium niobate

    Science.gov (United States)

    Amolo, G. O.; Comins, J. D.; Naidoo, S. R.; Connell, S. H.; Witcomb, M. J.; Derry, T. E.

    2006-09-01

    The optical effects of implantation of lithium niobate crystals with 100 keV Ag + and 8 MeV Au 3+ ions with fluences of 1 × 10 17 ions/cm 2 have been investigated. Metal nanoparticle formation has been studied as a function of annealing temperature, and the resulting optical extinction curves have been simulated by the Mie theory in the small particle limit. Transmission electron microscopy (TEM) has provided direct evidence for the MNP sizes allowing comparison with the calculated results. A TEM study of an X-cut sample implanted with Ag + ions show that the implanted region is partially amorphised. The differences in the temperature of Au colloid development in X- and Y-cut faces of the lithium niobate crystal are attributed to restoration of crystallinity as a result of annealing.

  11. Synthesis of Ag clusters in microemulsions: A time-resolved UV vis and fluorescence spectroscopy study

    Science.gov (United States)

    Ledo, Ana; Martínez, F.; López-Quintela, M. A.; Rivas, J.

    2007-09-01

    The combined use of the microemulsion technique and the kinetic control allows the preparation of small silver clusters. By using UV-vis and fluorescence spectroscopy the main stages by which the clusters grow, before the formation of nanoparticles, were elucidated. Transmission electron microscopy (TEM) and scanning tunnelling microscopy (STM) were used to further characterize the samples. Two main stages were clearly identified, which are associated with: (1) the formation of Ag n clusters with n<10, which self-aggregate into one atom high 2D nanodiscs of 3.2 nm size and (2) Ag n clusters, which self-aggregate into 3D nanostructures of 1.5 nm in size. The fluorescence properties observed with both stages show that the formed clusters are small enough to display a molecule-like behaviour.

  12. Structural, optical and electrical characterization of ITO, ITO/Ag and ITO/Ni transparent conductive electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Ahmad Hadi, E-mail: ahadi@uthm.edu.my [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, Penang (Malaysia); Science Department, Faculty of Science, Technology and Human Development, Universiti Tun Hussein Onn Malaysia, Johor (Malaysia); Shuhaimi, Ahmad [Low Dimensional Materials Research Centre, Department of Physics, Faculty of Science, Universiti Malaya, Kuala Lumpur (Malaysia); Hassan, Zainuriah [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, Penang (Malaysia)

    2014-01-01

    We report on the transparent conductive oxides (TCO) characteristics based on the indium tin oxides (ITO) and ITO/metal thin layer as an electrode for optoelectronics device applications. ITO, ITO/Ag and ITO/Ni were deposited on Si and glass substrate by thermal evaporator and radio frequency (RF) magnetron sputtering at room temperature. Post deposition annealing was performed on the samples in air at moderate temperature of 500 °C and 600 °C. The structural, optical and electrical properties of the ITO and ITO/metal were characterized using X-ray diffraction (XRD), UV–Vis spectrophotometer, Hall effect measurement system and atomic force microscope (AFM). The XRD spectrum reveals significant polycrystalline peaks of ITO (2 2 2) and Ag (1 1 1) after post annealing process. The post annealing also improves the visible light transmittance and electrical resistivity of the samples. Figure of merit (FOM) of the ITO, ITO/Ag and ITO/Ni were determined as 5.5 × 10{sup −3} Ω{sup −1}, 8.4 × 10{sup −3} Ω{sup −1} and 3.0 × 10{sup −5} Ω{sup −1}, respectively. The results show that the post annealed ITO with Ag intermediate layer improved the efficiency of the transparent conductive electrodes (TCE) as compared to the ITO and ITO/Ni.

  13. Effect of Ag doping on opto-electrical properties of CdS thin films for solar cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Nazir, Adnan, E-mail: adnan.nazir@iit.it [Istituto Italiano di Tecnologia, Via Morego 30, I-16163 Genova (Italy); School of Chemical and Materials Engineering, National University of Sciences and Technology, Islamabad (Pakistan); Toma, Andrea [Istituto Italiano di Tecnologia, Via Morego 30, I-16163 Genova (Italy); Shah, Nazar Abbas [Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Panaro, Simone [Istituto Italiano di Tecnologia, Via Morego 30, I-16163 Genova (Italy); Butt, Sajid [Department of Materials Science and Engineering, Institute of Space Technology (IST), Islamabad 44000 (Pakistan); School of Chemical and Materials Engineering, National University of Sciences and Technology, Islamabad (Pakistan); Sagar, Rizwan ur Rehman [Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Raja, Waseem [Istituto Italiano di Tecnologia, Via Morego 30, I-16163 Genova (Italy); Rasool, Kamran [Micro and Nano Devices Group, Department of Metallurgy and Materials Engineering Pakistan, Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad 45650 (Pakistan); Maqsood, Asghari [Department of Physics, Air University, Islamabad (Pakistan)

    2014-10-01

    Highlights: • Polycrystalline CdS thin films are fabricated by means of Close Spaced Sublimation technique. • Ag is doped by simple ion-exchange technique in order to reduce resistivity of CdS thin films. • Remarkable reduction in resistivity without introducing many transparency losses. - Abstract: Cadmium sulfide (CdS) polycrystalline thin films of different thicknesses (ranging from 370 nm to 750 nm) were fabricated on corning glass substrates using Close Spaced Sublimation (CSS) technique. Optical and electrical investigation revealed that CdS thin films show an appreciable transparency (50–70% transmission) in visible range and a highly resistive behavior (10{sup 6} Ω cm). Samples were doped by silver (Ag) at different concentrations, using ion exchange technique, in order to reduce the resistivity of CdS thin films and to improve their efficiency as a window layer for solar cell application. The doping of Ag in pure CdS thin films resulted into an increase of surface roughness and a decrease both in electrical resistivity and in transparency. By optimizing annealing parameters, we were able to properly control the optical properties of the present system. In fact, the Ag doping of pure CdS films has led to a decrease of the sample resistivity by three orders of magnitude (10{sup 3} Ω cm) against a 20% cut in optical transmission.

  14. Effect of Ag doping on opto-electrical properties of CdS thin films for solar cell applications

    International Nuclear Information System (INIS)

    Highlights: • Polycrystalline CdS thin films are fabricated by means of Close Spaced Sublimation technique. • Ag is doped by simple ion-exchange technique in order to reduce resistivity of CdS thin films. • Remarkable reduction in resistivity without introducing many transparency losses. - Abstract: Cadmium sulfide (CdS) polycrystalline thin films of different thicknesses (ranging from 370 nm to 750 nm) were fabricated on corning glass substrates using Close Spaced Sublimation (CSS) technique. Optical and electrical investigation revealed that CdS thin films show an appreciable transparency (50–70% transmission) in visible range and a highly resistive behavior (106 Ω cm). Samples were doped by silver (Ag) at different concentrations, using ion exchange technique, in order to reduce the resistivity of CdS thin films and to improve their efficiency as a window layer for solar cell application. The doping of Ag in pure CdS thin films resulted into an increase of surface roughness and a decrease both in electrical resistivity and in transparency. By optimizing annealing parameters, we were able to properly control the optical properties of the present system. In fact, the Ag doping of pure CdS films has led to a decrease of the sample resistivity by three orders of magnitude (103 Ω cm) against a 20% cut in optical transmission

  15. Biocompatible synthesis of silver nanoparticles (AgNPs using marine Vibrio sp. and study their pharmacological applications

    Directory of Open Access Journals (Sweden)

    M. Surya

    2015-09-01

    Full Text Available This report presents a rapid and a green biogenic approach for the biosynthesis of silver nanoparticles using marine bacteria such as Vibrio sp. The bioactive compounds of Vibrio sp. induced the reduction of Ag+ ions from AgNO3, which resulted in the formation of bacterial mediated silver nanoparticles (AgNPs. The reduction of Ag+ ions to elemental silver was characterized by UV-vis spectroscopy, Fourier transform infra-red spectroscopy (FTIR, Scanning electron microscopy (SEM and Dynamic light scattering (DLS. The nanoparticles show maximum absorbance at 421 nm on ultraviolet-visible spectra. The presence of biomolecules were identified by Fourier transform–infrared spectroscopy. The bioactive compounds and nanoparticles were found to direct different shape and sized and their size/ shape were varied. The silver nanoparticle synthesized were spherical, in the range of 40-80 nm in size. In antimicrobial screening, all the pathogens were fairly affected and nil effect was not observed in the test samples, In bacteria, the test sample was most effective against Enterococcus faecalis B2 and Salmonella typhimurium B5. In fungi, which was effective against Candida albicans F1, Microsporum canis F3 and Trichophyton rubrum F4.

  16. Show and Tell

    DEFF Research Database (Denmark)

    2013-01-01

    /DK), Pernille With Madsen, Emil Alenius, Andrés Galeano (E/DE), Kasper Vang & Mads Forsby, Nanna Lysholt Hansen og Molly & Me (Molly Haslund & Catherine Hoffmann (UK)) Kurateret af Judith Schwarzbart og Sanne Krogh Groth Produceret af studerende ved Performance-design Programmet var støttet af Statens Kunstråd...... og studienævnet på Performance-design. Show & Tell - Performance program: kl. 16.30-19 Adresse: Kunsthal Charlottenborg, Nyhavn 2, 1051 København K...

  17. Formation and properties of hyaluronan/nano Ag and hyaluronan-lecithin/nano Ag films.

    Science.gov (United States)

    Khachatryan, Gohar; Khachatryan, Karen; Grzyb, Jacek; Fiedorowicz, Maciej

    2016-10-20

    A facile and environmentally friendly method of the preparation of silver nanoparticles embedded in hyaluronan (Hyal/Ag) and hyaluronan-lecithin (Hyal-L/Ag) matrix was developed. Thin, elastic foils were prepared from gels by an in situ synthesis of Ag in an aqueous solution of sodium hyaluronate (Hyal), using aq. d-(+)-xylose solution as a reducing agent. The gels were applied to a clean, smooth, defatted Teflon surface and left for drying in the air. The dry foils were stored in a closed container. UV-vis spectroscopy, transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectra confirmed formation of about 10nm ball-shaped Ag nanoparticles situated within the polysaccharide template. Thermal properties of the composites were characterized involving differential scanning calorimetry (DSC) and thermogravimetric (TGA) analyses, whereas molecular weights of polysaccharide chains of the matrix were estimated with the size exclusion chromatography coupled with multiangle laser light scattering and refractometric detectors (HPSEC-MALLS-RI). An increase in the molecular weight of the hyaluronate after generation of Ag nanoparticles was observed. The foils showed specific properties. The study confirmed that silver nanoparticles can be successfully prepared with environmentally friendly method, using hyaluronan as a stabilizing template. Hyaluronan and hyaluronan-lecithin matrices provide nanocrystals uniform in size and shape. The composites demonstrated a bacteriostatic activity. PMID:27474588

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

    NARCIS (Netherlands)

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

    1997-01-01

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

  19. 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.

  20. Obesity in show dogs.

    Science.gov (United States)

    Corbee, R J

    2013-10-01

    Obesity is an important disease with a growing incidence. Because obesity is related to several other diseases, and decreases life span, it is important to identify the population at risk. Several risk factors for obesity have been described in the literature. A higher incidence of obesity in certain breeds is often suggested. The aim of this study was to determine whether obesity occurs more often in certain breeds. The second aim was to relate the increased prevalence of obesity in certain breeds to the official standards of that breed. To this end, we investigated 1379 dogs of 128 different breeds by determining their body condition score (BCS). Overall, 18.6% of the show dogs had a BCS >5, and 1.1% of the show dogs had a BCS>7. There were significant differences between breeds, which could be correlated to the breed standards. It warrants firm discussions with breeders and judges in order to come to different interpretations of the standards to prevent overweight conditions from being the standard of beauty. PMID:22882163

  1. Tunable Fano resonances in heterogenous Al-Ag nanorod dimer

    CERN Document Server

    Ci, Xueting; Song, Min; Liu, Yan; Chen, Gengxu; Wu, E; Zeng, Heping

    2013-01-01

    We theoretically investigate the plasmonic coupling in heterogenous Al-Ag nanorod dimer. A pronounced Fano dip is found in the extinction spectrum produced by the destructive interference between the bright dipole mode from a short Al nanorod and the dark quadrupole mode from a long Ag nanorod nearby. This Fano resonance can be widely tuned in both wavelength and amplitude by varying the rod dimensions, the separation distance and the local dielectric environment. The Al-Ag heterogeneous nanorod dimer shows a high sensitivity to the surrounding environment with a local surface plasmon resonance figure of merit of 7.0, which enables its promising applications in plasmonic sensing and detection.

  2. Adsorption of Ag on Ge(100)-(2 x 1)

    Energy Technology Data Exchange (ETDEWEB)

    Miller, T.; Rosenwinkel, E.; Chiang, T.C.

    1984-01-01

    The initial stages of interface formation of Ag deposited onto Ge(100)-(2 x 1) were studied with high-energy electron diffraction and high-resolution photoemission. The surface core-level energies for clean Ge(100)-(2 x 1) were not changed with the deposition of about one monolayer of Ag, indicating that there was no chemical reaction or atomic intermixing. The Ag nucleated at a coverage of about 1/3 monolayer and showed three-dimensional growth for higher coverages. 13 references, 3 figures.

  3. On the heterostructured photocatalysts Ag{sub 3}VO{sub 4}/g-C{sub 3}N{sub 4} with enhanced visible light photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Si-Zhan [School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640 (China); Institute of Materials Science and Chemical Industry, Tongren University, 103 Qingshui Road, Tongren 554300 (China); Li, Kui [School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640 (China); Zhang, Wei-De, E-mail: zhangwd@scut.edu.cn [School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640 (China)

    2015-01-01

    Highlights: • Novel Ag{sub 3}VO{sub 4}/g-C{sub 3}N{sub 4}-VN composite photocatalysts were prepared by a simple method. • Ag{sub 3}VO{sub 4}/g-C{sub 3}N{sub 4}-VN showed high activity toward degradation of RhB. • Ag{sub 3}VO{sub 4}/g-C{sub 3}N{sub 4}-VN composite with large surface area exhibited excellent stability. - Abstract: Heterostructured photocatalysts Ag{sub 3}VO{sub 4}/g-C{sub 3}N{sub 4} were prepared by deposition-precipitation method in order to anchor Ag{sub 3}VO{sub 4} on the surface of N-vacancy g-C{sub 3}N{sub 4} (g-C{sub 3}N{sub 4}-VN). The photocatalytic activity of the samples was evaluated by degrading rhodamine B (RhB) in aqueous solution. Compared with the pure Ag{sub 3}VO{sub 4} and g-C{sub 3}N{sub 4}-VN, the heterojuncted photocatalyst 65 wt% Ag{sub 3}VO{sub 4}/g-C{sub 3}N{sub 4}-VN exhibits the best activity under visible light irradiation. The photodegradation rate constant of 65 wt% Ag{sub 3}VO{sub 4}/g-C{sub 3}N{sub 4}-VN is 0.0556 min{sup −1}, which is 23.4, 5.8 and 6.4 times of that of pure Ag{sub 3}VO{sub 4}, pure g-C{sub 3}N{sub 4}-VN and P25, respectively. The excellent photocatalytic performance of the Ag{sub 3}VO{sub 4}/g-C{sub 3}N{sub 4}-VN catalysts can be ascribed to the matched band structures of Ag{sub 3}VO{sub 4} and g-C{sub 3}N{sub 4}, which strengthened the formation of the heterojuncted photocatalyst. The unique heterostructured photocatalyst is favorable for retarding the recombination of photogenerated electrons and holes, thus the photocatalytic activity is significantly increased. Further experiment also reveals that the • O{sub 2}{sup −} and h{sup +} are the major active species in the degradation of RhB.

  4. Visible light driven Ag/Ag3PO4/AC photocatalyst with highly enhanced photodegradation of tetracycline antibiotics

    Science.gov (United States)

    Wang, Huiqin; Ye, Zhefei; Liu, Chun; Li, Jinze; Zhou, Mingjun; Guan, Qingfeng; Lv, Peng; Huo, Pengwei; Yan, Yongsheng

    2015-10-01

    Ag/Ag3PO4/active carbon (AC) composite photocatalysts were successfully synthesized using the simple deposition and photoinduced methods. The structures, morphology and photocatalytic properties of as-prepared photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, X-ray photoelectron spectroscopy (XPS). The Ag/Ag3PO4/AC composite photocatalysts exhibited a conspicuously improved photocatalytic performance for tetracycline (TC) degradation. The optimal conditions of loaded dosage and photoinduced time were investigated, and the results showed that the photoinduced time played an important role in prepared processes, and also that for the loaded dosage of Ag3PO4. The DRS analysis showed that the composite photocatalysts exhibited strong absorption ability in the visible light range. The radicals trap experiments demonstrated that there were multiple active species during the degrading process of TC. The possible mechanism of improved photocatalytic activity of Ag-Ag3PO4/AC composite was also proposed.

  5. Not a "reality" show.

    Science.gov (United States)

    Wrong, Terence; Baumgart, Erica

    2013-01-01

    The authors of the preceding articles raise legitimate questions about patient and staff rights and the unintended consequences of allowing ABC News to film inside teaching hospitals. We explain why we regard their fears as baseless and not supported by what we heard from individuals portrayed in the filming, our decade-long experience making medical documentaries, and the full un-aired context of the scenes shown in the broadcast. The authors don't and can't know what conversations we had, what documents we reviewed, and what protections we put in place in each televised scene. Finally, we hope to correct several misleading examples cited by the authors as well as their offhand mischaracterization of our program as a "reality" show. PMID:23631336

  6. Not a "reality" show.

    Science.gov (United States)

    Wrong, Terence; Baumgart, Erica

    2013-01-01

    The authors of the preceding articles raise legitimate questions about patient and staff rights and the unintended consequences of allowing ABC News to film inside teaching hospitals. We explain why we regard their fears as baseless and not supported by what we heard from individuals portrayed in the filming, our decade-long experience making medical documentaries, and the full un-aired context of the scenes shown in the broadcast. The authors don't and can't know what conversations we had, what documents we reviewed, and what protections we put in place in each televised scene. Finally, we hope to correct several misleading examples cited by the authors as well as their offhand mischaracterization of our program as a "reality" show.

  7. Surface plasmon enhanced photoluminescence in amorphous silicon carbide films by adjusting Ag island film sizes

    International Nuclear Information System (INIS)

    Ag island films with different sizes are deposited on hydrogenated amorphous silicon carbide (α-SiC:H) films, and the influences of Ag island films on the optical properties of the α-SiC:H films are investigated. Atomic force microscope images show that Ag nanoislands are formed after Ag coating, and the size of the Ag islands increases with increasing Ag deposition time. The extinction spectra indicate that two resonance absorption peaks which correspond to out-of-plane and in-plane surface plasmon modes of the Ag island films are obtained, and the resonance peak shifts toward longer wavelength with increasing Ag island size. The photoluminescence (PL) enhancement or quenching depends on the size of Ag islands, and PL enhancement by 1.6 times on the main PL band is obtained when the sputtering time is 10 min. Analyses show that the influence of surface plasmons on the PL of α-SiC:H is determined by the competition between the scattering and absorption of Ag islands, and PL enhancement is obtained when scattering is the main interaction between the Ag islands and incident light. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  8. Fate of Ag-NPs in Sewage Sludge after Application on Agricultural Soils.

    Science.gov (United States)

    Pradas del Real, Ana E; Castillo-Michel, Hiram; Kaegi, Ralf; Sinnet, Brian; Magnin, Valérie; Findling, Nathaniel; Villanova, Julie; Carrière, Marie; Santaella, Catherine; Fernández-Martínez, Alejandro; Levard, Clément; Sarret, Géraldine

    2016-02-16

    The objective of this work was to investigate the fate of silver nanoparticles (Ag-NPs) in a sludge-amended soil cultivated with monocot (Wheat) and dicot (Rape) crop species. A pot experiment was performed with sludges produced in a pilot wastewater treatment plant containing realistic Ag concentrations (18 and 400 mg kg(-1), 14 mg kg(-1) for the control). Investigations focused on the highest dose treatment. X-ray absorption spectroscopy (XAS) showed that Ag2S was the main species in the sludge and amended soil before and after plant culture. The second most abundant species was an organic and/or amorphous Ag-S phase whose proportion slightly varied (from 24% to 36%) depending on the conditions. Micro and nano X-ray fluorescence (XRF) showed that Ag was preferentially associated with S-rich particles, including organic fragments, of the sludge and amended soils. Ag was distributed as heteroaggregates with soil components (size ranging from ≤0.5 to 1-3 μm) and as diffused zones likely corresponding to sorbed/complexed Ag species. Nano-XRF evidenced the presence of mixed metallic sulfides. Ag was weakly exchangeable and labile. However, micronutrient mobilization by plant roots and organic matter turnover may induce Ag species interconversion eventually leading to Ag release on longer time scales. Together, these data provide valuable information for risk assessment of sewage sludge application on agricultural soils. PMID:26756906

  9. Structural studies on the substitution of Ag, Na doped LCSMO CMR manganites

    Science.gov (United States)

    Subhashini, P.; Munirathinam, B.; Krishnaiah, M.; Venkatesh, R.; Venkateswarlu, D.; Ganesan, V.

    2016-05-01

    Synthesis and characterization of colossal magnetoresistance (CMR) materials has been a subject of scientific research due to the unique transport, magnetotransport, and magnetic properties. The single phase polycrystalline La0.7Ca0.1Sr0.1M0.1MnO3 (LCSMO) (M=Ag and Na) samples prepared using nitrate route method. The structural properties are studied at different dopants by X-ray diffraction. The surface morphology and elemental analysis of both samples were carried out by scanning electron microscopy (SEM) and energy dispersive X-ray technique (EDAX) respectively. The structural analysis shows that the LCSMO is crystallized in an orthorhombic perovskite structure belonging to Pnma space group. The crystal size of the sample is calculated using Scherrer formula. The SEM images show that the polycrystalline grains are observed to be near spherical shape and uniform in size. EDAX spectra taken from the surface of the synthesized powders show a nominal composition near the desired one for M=Na sample where as some vacancies are present in the A-site in the case of Ag substitution as will be discussed in this paper.

  10. Polar Kerr spectroscopic magneto-optics in Au/Co-Ag/Ag granular thin films on glass: Experiments and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Borcia, I.D. [Faculty of Physics, Alexandru Ioan Cuza University, 6600 Iasi (Romania); Beauvillain, P. [Institut d' Electronique Fondamentale, Universite Paris-Sud, UMR CNRS 8622, 91405 Orsay Cedex (France)]. E-mail: Pierre.Beauvillain@ief.u-psud.fr; Bartenlian, B. [Institut d' Electronique Fondamentale, Universite Paris-Sud, UMR CNRS 8622, 91405 Orsay Cedex (France); Gogol, P. [Institut d' Electronique Fondamentale, Universite Paris-Sud, UMR CNRS 8622, 91405 Orsay Cedex (France); Megy, R. [Institut d' Electronique Fondamentale, Universite Paris-Sud, UMR CNRS 8622, 91405 Orsay Cedex (France)

    2006-06-15

    In Au/Co-Ag/Ag granular thin films, linear polar magneto-optical Kerr spectra were measured in the 250-800 nm wavelength range. These experimental spectra were compared to magneto-optical (MO) simulations using an optical multilayer model based on matrix formalism. MO simulations using homogenous layers of uniform thickness led to a great difference of amplitude and shape between the measured and simulated curves. Atomic force microscopy and scanning electron microscopy images were used to estimate the granular structure of the samples and determine the mean diameter and height, respectively of the Ag and Ag-Co islands of each layer. Using this granular structure in our MO simulations, a reasonable agreement between the simulations and MO experiments was obtained for both the Kerr rotation and ellipticity spectra.

  11. Enhanced HBsAg synthesis correlates with increased severity of fibrosis in chronic hepatitis B patients.

    Directory of Open Access Journals (Sweden)

    Mei-Zhu Hong

    Full Text Available BACKGROUND AND AIMS: Little is known about whether low serum HBsAg levels result from impaired HBsAg synthesis or a reduced number of hepatocytes caused by advanced liver fibrosis. Therefore, we investigated the capacity for HBsAg synthesis in a cross-sectional cohort of treatment-naïve chronic hepatitis B patients. METHODS: Chronic hepatitis B patients (n = 362 were enrolled; liver biopsies were performed and liver histology was scored, and serum HBsAg and HBV DNA levels were investigated. In the enrolled patients, 183 out of 362 have quantitative serum HBsAg levels. Tissue HBsAg was determined by immunohistochemistry. RESULTS: A positive correlation between serum HBsAg and HBV DNA levels was revealed in HBeAg(+ patients (r = 0.2613, p = 0.0050. In HBeAg(+ patients, serum HBsAg and severity of fibrosis were inversely correlated (p = 0.0094, whereas tissue HBsAg levels correlated positively with the stage of fibrosis (p = 0.0280. After applying the mean aminopyrine breath test as a correction factor, adjusted serum HBsAg showed a strong positive correlation with fibrosis severity in HBeAg(+ patients (r = 0.5655, p<0.0001. The adjusted serum HBsAg values predicted 'moderate to severe' fibrosis with nearly perfect performance in both HBeAg(+ patients (area under the curve: 0.994, 95% CI: 0.983-1.000 and HBeAg(- patients (area under the curve: 1.000, 95% CI: 1.000-1.000. CONCLUSIONS: Although serum HBsAg levels were negatively correlated with fibrosis severity in HBeAg(+ patients, aminopyrine breath test-adjusted serum HBsAg and tissue HBsAg, two indices that are unaffected by the number of residual hepatocytes, were positively correlated with fibrosis severity. Furthermore, adjusted serum HBsAg has an accurate prediction capability.

  12. Enhanced formation of silver nanoparticles in Ag+-NOM-iron(II, III) systems and antibacterial activity studies.

    Science.gov (United States)

    Adegboyega, Nathaniel F; Sharma, Virender K; Siskova, Karolina M; Vecerova, Renata; Kolar, Milan; Zbořil, Radek; Gardea-Torresdey, Jorge L

    2014-03-18

    This work reports the role of iron redox pair (Fe(3+)/Fe(2+)) in the formation of naturally occurring silver nanoparticles (AgNPs) in the aquatic environment. The results showed that Fe(3+) or Fe(2+) ions in the mixtures of Ag(+) and natural organic matter enhanced the formation of AgNPs. The formation of AgNPs depended on pH and types of organic matter. Increase in pH enhanced the formation of AgNPs, and humic acids as ligands showed higher formation of AgNPs compared to fulvic acids. The observed results were described by considering the potentials of redox pairs of silver and iron species and the possible species involved in reducing silver ions to AgNPs. Dynamic light scattering and transmission electron microscopy measurements of AgNPs revealed mostly bimodal size distribution with decrease in size of AgNPs due to iron species in the reaction mixture. Minimum inhibitory concentration of AgNPs needed to inhibit the growth of various bacterial species suggested the role of surfaces of tested Gram-positive and Gram-negative bacteria. Stability study of AgNPs, formed in Ag(+)-humic acid/fulvic acids-Fe(3+) mixtures over a period of several months showed high stability of the particles with significant increase in surface plasmon resonance peak. The environmental implications of the results in terms of fate, transport, and ecotoxicity of organic-coated AgNPs are briefly presented. PMID:24524189

  13. Immobilization of Highly Dispersed Ag Nanoparticles on Carbon Nanotubes Using Electron-Assisted Reduction for Antibacterial Performance.

    Science.gov (United States)

    Yan, Xiaoliang; Li, Sha; Bao, Jiehua; Zhang, Nan; Fan, Binbin; Li, Ruifeng; Liu, Xuguang; Pan, Yun-Xiang

    2016-07-13

    Silver nanoparticles (Ag NPs) supported on certain materials have been widely used as disinfectants. Yet, to date, the antibacterial activity of the supported Ag NPs is still far below optimum. This is mainly associated with the easy aggregation of Ag NPs on the supporting materials. Herein, an electron-assisted reduction (EAR) method, which is operated at temperatures as low as room temperature and without using any reduction reagent, was employed for immobilizing highly dispersed Ag NPs on aminated-CNTs (Ag/A-CNTs). The average Ag NPs size on the EAR-prepared Ag/A-CNTs is only 3.8 nm, which is much smaller than that on the Ag/A-CNTs fabricated from the traditional thermal calcination (25.5 nm). Compared with Ag/A-CNTs fabricated from traditional thermal calcination, EAR-prepared Ag/A-CNTs shows a much better antibacterial activity to E. coli/S. aureus and antifouling performance to P. subcordiformis/T. lepidoptera. This is mainly originated from the significantly enhanced Ag(+) ion releasing rate and highly dispersed Ag NPs with small size on the EAR-prepared Ag/A-CNTs. The findings from the present work are helpful for fabricating supported Ag NPs with small size and high dispersion for efficient antibacterial process. PMID:27327238

  14. Direct observation of Ag filament growth and unconventional SET-RESET operation in GeTe amorphous films

    Science.gov (United States)

    Imanishi, Yusuke; Kida, Shimon; Nakaoka, Toshihiro

    2016-07-01

    We report on the direct observation of Ag filament growth and a peculiar resistance switching in amorphous GeTe films with a lateral electrode geometry. The Ag filament growth was monitored by in-situ optical microscopy. The resistance switching was studied in three electrode pairs, Ag-Ag, Pt-Ag, and Pt-Ag/Pt (Ag electrode covered with Pt). In all the three electrode pairs, similar dendritic Ag filaments were clearly observed growing along both directions from one electrode to the other, according to the applied bias polarity. However, the SET and RESET processes are quite different. The Ag-Ag pair produces a unipolar clockwise switching. The Pt-Ag pair shows a bipolar counter-clockwise switching, as predicted in the basic electrochemical metallization theory, but the observed switching polarity is exactly opposite to the basic theory prediction. The Pt-Ag/Pt pair produces a unipolar counter-clockwise switching. The peculiar SET/RESET processes are explained on the basis of strong Ag diffusion into GeTe matrix resulting in an asymmetric effective electrode pair. The findings suggest that the SET/RESET processes are controlled by the amount of Ag and the electrode geometry.

  15. Critical interparticle distance for the remarkably enhanced dielectric constant of BaTiO3-Ag hybrids filled polyvinylidene fluoride composites

    Science.gov (United States)

    Luo, Suibin; Yu, Shuhui; Fang, Fang; Lai, Maobai; Sun, Rong; Wong, Ching-Ping

    2014-06-01

    Discrete nano Ag-deposited BaTiO3 (BT-Ag) hybrids with varied Ag content were synthesized, and the hybrids filled polyvinylidene fluoride (PVDF) composites were prepared. The effect of Ag content on the dielectric properties of the composites were analyzed based on the diffused electrical double layer theory. Results showed that with a higher Ag content in BT-Ag hybrids, the dielectric constant of BT-Ag/PVDF composites increases fast with the filler loading, while the dielectric loss and conductivity showed a suppressed and moderate increase. The dielectric constant of BT-0.61Ag/PVDF (61 wt. % of Ag in BT-Ag hybrid) composites reached 613, with the dielectric loss of 0.29 at 1 kHz. It was deduced that remarkably enhanced dielectric constant appeared when the interparticle distance decreased to a critical value of about 20 nm.

  16. Showing Value (Editorial

    Directory of Open Access Journals (Sweden)

    Denise Koufogiannakis

    2009-06-01

    Full Text Available When Su Cleyle and I first decided to start Evidence Based Library and Information Practice, one of the things we agreed upon immediately was that the journal be open access. We knew that a major obstacle to librarians using the research literature was that they did not have access to the research literature. Although Su and I are both academic librarians who can access a wide variety of library and information literature from our institutions, we belong to a profession where not everyone has equal access to the research in our field. Without such access to our own body of literature, how can we ever hope for practitioners to use research evidence in their decision making? It would have been contradictory to the principles of evidence based library and information practice to do otherwise.One of the specific groups we thought could use such an open access venue for discovering research literature was school librarians. School librarians are often isolated and lacking access to the research literature that may help them prove to stakeholders the importance of their libraries and their role within schools. Certainly, school libraries have been in decline and the use of evidence to show value is needed. As Ken Haycock noted in his 2003 report, The Crisis in Canada’s School Libraries: The Case for Reform and Reinvestment, “Across the country, teacher-librarians are losing their jobs or being reassigned. Collections are becoming depleted owing to budget cuts. Some principals believe that in the age of the Internet and the classroom workstation, the school library is an artifact” (9. Within this context, school librarians are looking to our research literature for evidence of the impact that school library programs have on learning outcomes and student success. They are integrating that evidence into their practice, and reflecting upon what can be improved locally. They are focusing on students and showing the impact of school libraries and

  17. 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

  18. 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

  19. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

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

  20. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

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

  1. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

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

  2. 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-

  3. 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

  4. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

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

  5. AGS Experiments: 1989, 1990, 1991

    International Nuclear Information System (INIS)

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

  6. 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.

  7. 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.

  8. Investigation of the chaperone function of the small heat shock protein — AgsA

    Directory of Open Access Journals (Sweden)

    Nagamune Hideaki

    2010-07-01

    Full Text Available Abstract Background A small heat shock protein AgsA was originally isolated from Salmonella enterica serovar Typhimurium. We previously demonstrated that AgsA was an effective chaperone that could reduce the amount of heat-aggregated proteins in an Escherichia coli rpoH mutant. AgsA appeared to promote survival at lethal temperatures by cooperating with other chaperones in vivo. To investigate the aggregation prevention mechanisms of AgsA, we constructed N- or C-terminal truncated mutants and compared their properties with wild type AgsA. Results AgsA showed significant overall homology to wheat sHsp16.9 allowing its three-dimensional structure to be predicted. Truncations of AgsA until the N-terminal 23rd and C-terminal 11th amino acid (AA from both termini preserved its in vivo chaperone activity. Temperature-controlled gel filtration chromatography showed that purified AgsA could maintain large oligomeric complexes up to 50°C. Destabilization of oligomeric complexes was observed for N-terminal 11- and 17-AA truncated AgsA; C-terminal 11-AA truncated AgsA could not form large oligomeric complexes. AgsA prevented the aggregation of denatured lysozyme, malate dehydrogenase (MDH and citrate synthase (CS but did not prevent the aggregation of insulin at 25°C. N-terminal 17-AA truncated AgsA showed no chaperone activity towards MDH. C-terminal 11-AA truncated AgsA showed weak or no chaperone activity towards lysozyme, MDH and CS although it prevented the aggregation of insulin at 25°C. When the same amount of AgsA and C-terminal 11-AA truncated AgsA were mixed (half of respective amount required for efficient chaperone activities, good chaperone activity for all substrates and temperatures was observed. Detectable intermolecular exchanges between AgsA oligomers at 25°C were not observed using fluorescence resonance energy transfer analysis; however, significant exchanges between AgsA oligomers and C-terminal truncated AgsA were observed at 25

  9. The Great Cometary Show

    Science.gov (United States)

    2007-01-01

    its high spatial and spectral resolution, it was possible to zoom into the very heart of this very massive star. In this innermost region, the observations are dominated by the extremely dense stellar wind that totally obscures the underlying central star. The AMBER observations show that this dense stellar wind is not spherically symmetric, but exhibits a clearly elongated structure. Overall, the AMBER observations confirm that the extremely high mass loss of Eta Carinae's massive central star is non-spherical and much stronger along the poles than in the equatorial plane. This is in agreement with theoretical models that predict such an enhanced polar mass-loss in the case of rapidly rotating stars. ESO PR Photo 06c/07 ESO PR Photo 06c/07 RS Ophiuchi in Outburst Several papers from this special feature focus on the later stages in a star's life. One looks at the binary system Gamma 2 Velorum, which contains the closest example of a star known as a Wolf-Rayet. A single AMBER observation allowed the astronomers to separate the spectra of the two components, offering new insights in the modeling of Wolf-Rayet stars, but made it also possible to measure the separation between the two stars. This led to a new determination of the distance of the system, showing that previous estimates were incorrect. The observations also revealed information on the region where the winds from the two stars collide. The famous binary system RS Ophiuchi, an example of a recurrent nova, was observed just 5 days after it was discovered to be in outburst on 12 February 2006, an event that has been expected for 21 years. AMBER was able to detect the extension of the expanding nova emission. These observations show a complex geometry and kinematics, far from the simple interpretation of a spherical fireball in extension. AMBER has detected a high velocity jet probably perpendicular to the orbital plane of the binary system, and allowed a precise and careful study of the wind and the shockwave

  10. 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.

  11. Failure Mechanism of Ag/AgCl Reference Electrode Due to Current Leakage%银/氯化银参比电极漏电流情况下的失效机理

    Institute of Scientific and Technical Information of China (English)

    陆文萍; 尹鹏飞; 许立坤; 辛永磊

    2013-01-01

    采用热浸涂-电化学还原方法制备了Ag/AgCl参比电极,通过加速极化试验方法研究了电极失效过程及机理.采用扫描电子显微镜(SEM)、能谱仪(EDX)和电化学阻抗(EIS)测试手段研究了电极失效过程中表面状态、形貌及性能的变化.结果表明,Ag/AgCl参比电极失效后电极电位出现大幅波动,电极表面呈疏松多孔结构,AgC1完全转化为银,Ag/AgCl参比电极在漏电流情况下失效的主要原因是电极中AgC1被还原为银所致.%A Ag/AgCl reference electrode was prepared by thermal-dip coating followed by electrochemical reduction. The failure mechanism of the electrode was studied by accelerated polarization method. The microstructure and performance of the electrode were analyzed by scanning electron microscopy (SEM), energy dispersed X-ray spectroscopy(EDX), and electrochemical impedance spectroscopy(EIS). After the acceleration test, the potential of the Ag/AgCl reference electrode fluctuated grjeatly, and the electrode surface showed a morphology of porous structure. EDX results indicate that AgCl transformed into Ag completely on the electrode surface. So, the failure of Ag/AgCl reference electrode could be attributed to the complete transformation of AgCl into Ag.

  12. Single-molecule conductance with nitrile and amino contacts with Ag or Cu electrodes

    International Nuclear Information System (INIS)

    The single-molecule conductance of 1,4-dicyanobenzene (DCB), 1,4-benzenediamine (BDA) and 4,4'-biphenyldicarbonitrile (BPDC) with Ag and/or Cu electrodes is measured by electrochemical jump-to-contact STM-break junction. All single-molecule junctions present three sets of conductance values revealing different contact geometries. We observe that the single-molecule conductance of Ag-BDA-Ag junction is larger that of Ag-DCB-Ag junction, and DCB with Ag contacts are more conductive than that with Cu ones. This is related to a different electronic coupling between the molecules and the electrodes. Tunneling decay constants of 1.70 and 1.68 per phenyl group were found for Ag and Cu electrodes, respectively. The present study therefore shows that nitrile and amino groups can also be used as effective anchors for other metals than gold

  13. Low emissivity Ag/Ta/glass multilayer thin films deposited by sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sun Ho [Division of Advanced Materials Engineering, Kongju National University, Budaedong, Cheonan City (Korea, Republic of); Lee, Kee Sun [Division of Advanced Materials Engineering, Kongju National University, Budaedong, Cheonan City (Korea, Republic of); Green Home Energy Technology Center, Cheonan City (Korea, Republic of); Sivasankar Reddy, A. [Green Home Energy Technology Center, Cheonan City (Korea, Republic of)

    2011-09-15

    Ta is deposited on a glass substrate as an interlayer for the two-dimensional growth of Ag thin films because Ta has good thermal stability and can induce a negative surface-energy change in Ag/glass. From the transmission electron microscopy results, we concluded that the Ag crystals in the bottom layer (seemingly on Ag/Ta) were flattened; this was rarely observed in the three-dimensional growth mode. Comparing Ag/Ta/glass with Ag/glass, we found that the Ta interlayer was effective in reducing both the resistance and the emissivity, accompanied by the relatively high transmittance in the visible region. In particular, Ag(9 nm)/Ta(1 nm)/glass film showed 0.08 of the emissivity, including {approx}61% of the transmittance in the visible region (wavelength: 550 nm).

  14. Low emissivity Ag/Ta/glass multilayer thin films deposited by sputtering

    International Nuclear Information System (INIS)

    Ta is deposited on a glass substrate as an interlayer for the two-dimensional growth of Ag thin films because Ta has good thermal stability and can induce a negative surface-energy change in Ag/glass. From the transmission electron microscopy results, we concluded that the Ag crystals in the bottom layer (seemingly on Ag/Ta) were flattened; this was rarely observed in the three-dimensional growth mode. Comparing Ag/Ta/glass with Ag/glass, we found that the Ta interlayer was effective in reducing both the resistance and the emissivity, accompanied by the relatively high transmittance in the visible region. In particular, Ag(9 nm)/Ta(1 nm)/glass film showed 0.08 of the emissivity, including ∼61% of the transmittance in the visible region (wavelength: 550 nm).

  15. Enhanced photocatalytic, electrochemical and photoelectrochemical properties of TiO2 nanotubes arrays modified with Cu, AgCu and Bi nanoparticles obtained via radiolytic reduction

    Science.gov (United States)

    Nischk, Michał; Mazierski, Paweł; Wei, Zhishun; Siuzdak, Katarzyna; Kouame, Natalie Amoin; Kowalska, Ewa; Remita, Hynd; Zaleska-Medynska, Adriana

    2016-11-01

    TiO2 nanotubes arrays (NTs), obtained via electrochemical anodization of Ti foil, were modified with monometallic (Cu, Bi) and bimetallic (AgCu) nanoparticles. Different amounts of metals' precursors were deposited on the surface of NTs by the spin-coating technique, and the reduction of metals was performed via gamma radiolysis. Surface modification of titania was studied by EDS and XPS analysis. The results show that AgCu nanoparticles exist in a Agcore-Cushell form. Photocatalytic activity was examined under UV irradiation and phenol was used as a model pollutant of water. Over 95% of phenol degradation was achieved after 60 min of irradiation for almost all examined samples, but only slight difference in degradation efficiency (about 3%) between modified and bare NTs was observed. However, the initial phenol degradation rate and TOC removal efficiency was significantly enhanced for the samples modified with 0.31 and 0.63 mol% of Bi as well as for all the samples modified with Cu and AgCu nanoparticles in comparison with bare titania nanotubes. The saturated photocurrent, under the influence of simulated solar light irradiation, for the most active Bi- and AgCu-modified samples, was over two times higher than for pristine NTs. All the examined materials were resistant towards photocorrosion processes that enables their application for long term processes induced by light.

  16. Single-step solvothermal synthesis of mesoporous Ag-TiO2-reduced graphene oxide ternary composites with enhanced photocatalytic activity

    Science.gov (United States)

    Arif Sher Shah, Md. Selim; Zhang, Kan; Park, A. Reum; Kim, Kwang Su; Park, Nam-Gyu; Park, Jong Hyeok; Yoo, Pil J.

    2013-05-01

    of AgNO3 and graphene oxide and the hydrolysis of titanium tetraisopropoxide were spontaneously performed in a mixed solvent system of ethylene glycol, N,N-dimethylformamide and a stoichiometric amount of water without resorting to the use of typical reducing agents. The nanocomposites were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, along with different microscopic and spectroscopic techniques, enabling us to confirm the successful reduction of AgNO3 and graphite oxide to metallic Ag and reduced graphene oxide, respectively. Due to the highly facilitated electron transport of well distributed Ag nanoparticles, the synthesized ternary nanocomposite showed enhanced photocatalytic activity for degradation of rhodamine B dye under visible light irradiation. Electronic supplementary information (ESI) available: XRD of GO, EDX analysis of AgTG composites, tables show the size of graphitic domains and peak area analysis, dye adsorption plot, UV-visible absorption spectra of dye at different times, and plots of ln(Ct/C0) vs. time with the corresponding fitting curves of different samples. See DOI: 10.1039/c3nr00579h

  17. Density functional theory study on the structural and electronic properties of Ag-adsorbed (MgO)n clusters

    Institute of Scientific and Technical Information of China (English)

    GE GuiXian; JING Qun; LUO YouHua

    2009-01-01

    Equilibrium geometries, charge distributions, stabilities and electronic properties of the Ag-adsorbed (MgO)n(n=1-8) clusters have been investigated by density functional theory (DFT)with generalized gradient approximation (GGA) for exchange-correlation functional. The results show that hollow site is energetically preferred for n≥4, and the incoming Ag atoms tend to cluster on the existing Ag cluster.The Mulliken populations indicate that the interaction between the Ag atom and Magnesia clusters is mainly induced by a weak atomic polarization. The adsorbed Ag atom only causes charge redistributions of the atoms near itself. The effect of the adsorbed Ag atom on the bonding natures and structural features of Magnesia clusters is minor. Furthermore, the investigations on the first energy difference,fragmentation energies and electron affinities show that the Ag(MgO)4 and Ag(MgO)6 are the most stable among studied clusters.

  18. Density functional theory study on the structural and electronic properties of Ag-adsorbed (MgO)_n clusters

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Equilibrium geometries, charge distributions, stabilities and electronic properties of the Ag-adsorbed (MgO)n (n = 1-8) clusters have been investigated by density functional theory (DFT) with generalized gradient approximation (GGA) for exchange-correlation functional. The results show that hollow site is energetically preferred for n≥4, and the incoming Ag atoms tend to cluster on the existing Ag cluster. The Mulliken populations indicate that the interaction between the Ag atom and Magnesia clusters is mainly induced by a weak atomic polarization. The adsorbed Ag atom only causes charge redistributions of the atoms near itself. The effect of the adsorbed Ag atom on the bonding natures and structural features of Magnesia clusters is minor. Furthermore, the investigations on the first energy difference, fragmentation energies and electron affinities show that the Ag(MgO)4 and Ag(MgO)6 are the most stable among studied clusters.

  19. Height preference and strain in Ag islands on Si(111)-(7x7)

    OpenAIRE

    Goswami, D. K.; Bhattacharjee, K.; Satpati, B.; Roy, S; Kuri, G.; Satyam, P. V.; Dev, B. N.

    2003-01-01

    Growth and strain behavior of thin Ag films on Si substrate have been investigated by scanning tunneling microscopy, cross-sectional transmission electron microscopy and high resolution x-ray diffraction studies. Ag islands formed on Si at room temperature growth show strongly preferred heights and flat top. At low coverage, islands containing two atomic layers of Ag are overwhelmingly formed. At higher coverages island height distribution shows strong peaks at relative heights corresponding ...

  20. Novel Mn3 [Co(CN)6]2@SiO2@Ag Core-Shell Nanocube: Enhanced Two-Photon Fluorescence and Magnetic Resonance Dual-Modal Imaging-Guided Photothermal and Chemo-therapy.

    Science.gov (United States)

    Wang, Dongdong; Guo, Zhen; Zhou, Jiajia; Chen, Jian; Zhao, Gaozheng; Chen, Ruhui; He, Mengni; Liu, Zhenbang; Wang, Haibao; Chen, Qianwang

    2015-11-25

    The versatile Mn3[Co(CN)6]2@SiO2@Ag core-shell NCs are prepared by a simple coprecipitation method. Ag nanoparticles with an average diameter of 12 nm deposited on the surface of Mn3[Co(CN)6]2@SiO2 through S-Ag bonding are fabricated in ethanol solution by reducing silver nitrate (AgNO3 ) with NaBH4 . The NCs possess T1 -T2 dual-modal magnetic resonance imaging ability. The inner Prussian blue analogs (PBAs) Mn3[Co(CN)6]2 exhibit bright two-photon fluorescence (TPF) imaging when excited at 730 nm. Moreover, the TPF imaging intensity displays 1.85-fold enhancement after loading of Ag nanoparticles. Besides, the sample also has multicolor fluorescence imaging ability under 403, 488, and 543 nm single photon excitation. The as-synthesized Mn3[Co(CN)6]2@SiO2@Ag NCs show a DOX loading capacity of 600 mg g(-1) and exhibit an excellent ability of near-infrared (NIR)-responsive drug release and photothermal therapy (PTT) which is induced from the relative high absorbance in NIR region. The combined chemotherapy and PTT against cancer cells in vitro test shows high therapeutic efficiency. The multimodal treatment and imaging could lead to this material a potential multifunctional system for biomedical diagnosis and therapy. PMID:26437078

  1. 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+.

  2. 马铃薯黑痣病菌AG2-1和AG3融合群分析%Analysis on Anastomosis Groups of Rhizoctonia solani AG2-1 and AG3 from Potato(Solanum tuberosum)

    Institute of Scientific and Technical Information of China (English)

    王宇; 杨志辉; 秦宇轩; 朱杰华

    2013-01-01

    Current classification within Rhizoctonia solani is largely based on grouping of the population into anastomosis groups (AG), but does not always appear to accurately reflect the genetic variability among population. Hyphal anastomosis reactions and internal transcribed spacer (ITS) sequences were integrated to evaluate the genetic diversity of isolates Rhizoctonia solani AG2-1 and AG3 from potato (Solanum tuberosum). Anastomosis reactions indicated that the complete fusion reaction occurred among the different isolates of AG3. Either the complete fusion reaction or incomplete one occurred among the traditionally defined isolates of AG2-1. Therefore, AG2-1 was grouped into two sub-groups by incomplete fusion reaction. Phylogenetic tree constructed by ITS sequences showed that the AG3 formed only one separated clade, whereas AG2-1 clustered into the two different sub-clades. The horizontal lengths of the branches indicated that AG2-1 has been appearing obvious genetic differentiation because the relative genetic diversity of AG2-1 or the two subgroup AG2-1-1 and AG2-1-2 were higher than that of AG3. Based on ITS sequences, the two sub-clades within AG2-1 were consistent with the two sub-groups based on the incomplete anastomosis reaction. So the incomplete fusion reaction can be used as a referent character for genetic differentiation within an anastomosis group of Rhizoctonia solani.%采用菌丝融合分类法对立枯丝核菌进行融合群的划分,有时不能准确地反映该菌群体间的遗传变异.本研究通过菌丝融合反应、ITS序列分析对马铃薯黑痣病菌(Rhizoctonia solani)AG2-1和AG3两个融合群进行了遗传变异研究.对马铃薯黑痣病菌AG2-1和AG3融合反应测定表明,AG3融合群菌株间为完全融合,而AG2-1菌株间存在完全融合和不完全融合现象,根据不完全融合现象可将AG2-1划分为两组.通过ITS序列构建的系统发育树表明,AG3形成单一的分支,而AG2-1可分为明显的两个分支,并且AG

  3. The Kv channel blocker 4-aminopyridine enhances Ag+ uptake: A scanning electrochemical microscopy study of single living cells

    OpenAIRE

    Zhan, Dongping; Fan, Fu-Ren F.; Bard, Allen J.

    2008-01-01

    We report that silver ion (Ag+) uptake is enhanced by 4-aminopyridine (4-AP), a well known voltage-sensitive potassium ion channel (Kv) blocker. Both bacterial (Escherichia coli) and mammalian (3T3 fibroblast) cells were used as model systems. Ag+ uptake was monitored with a scanning electrochemical microscope with an amperometric Ag+ ion-selective electrode (Ag+-ISE) and the respiration rates of E. coli cells were measured by oxygen reduction at an ultramicroelectrode. The results showed tha...

  4. Structure and magnetic properties of [FePt/Ag]10 multilayer films

    Institute of Scientific and Technical Information of China (English)

    XU Xiaohong; WANG Fang; WU Haishun

    2004-01-01

    [FePt/Ag]10 multilayers were deposited on glass substrates by magnetron sputtering. After being annealed at 550℃ for 30 min, the coercivities of [FePt/Ag]10 multilayer films were observably improved. Magnetic properties of [FePt/Ag]10 multilayer films are influenced by the Ag content. The highest coercivity is obtained for those multilayer films that the Ag content is about 25%. The analysis for the remanence curves shows that the lower FePt layer thickness is favorable for decreasing the intergranular interaction. Result of XRD shows that a thick Ag layer can enhance the intensity of FePt(001) peak. A magnetic activation volume of the order of 10-24 m3 is obtained by the measurement of magnetic viscosity, showing that it is promising to be ultrahigh density recording media.

  5. SHOW

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    鞋如其人,由一个人对鞋的选择,便可知道他的兴趣与品位所在。无论是球星、艺人还是任何一位你可以叫得出名字的人,无论是在球场上、秀场上还是随处可以偶遇的街头巷尾,你都可以见到NIKE、adidas抑或是奢侈的LV.

  6. SHOW

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    鞋如其人,由一个人对鞋的选择,便可知道他的兴趣与品位所在。无论是球星、艺人还是任何一位你可以叫得出名字的人,无论是在球场上、秀场上还是随处可以偶遇的等着巷尾,你都可以见到NIKE、adidas抑或是奢侈的LV.

  7. SHOW

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    鞋如其人,由一个人对鞋的选择,便可知道他的兴趣与品位所在。无论是球星、艺人还是任何一位你可以叫得出名字的人,无论是在球场上、秀场上还是随处可以偶遇的街头巷尾,你都可以见到NIKE、adidas抑或是奢侈的LV。

  8. Facile synthesis of Ag-reduced graphene oxide hybrids and their application in electromagnetic interference shielding

    Science.gov (United States)

    Long, Tao; Hu, Li; Dai, HongXia; Tang, YuXia

    2014-07-01

    A fast and environmentally friendly method was proposed toward one-pot synthesis of Ag-reduced graphene oxide (Ag-RGO) hybrids by a chemical reduction method assisted by microwave irradiation treatment with the use of sodium citrate as green reductant. The as-synthesized samples were characterized systematically, and the results indicated the successful synthesis of Ag-RGO. Ag-RGO was further applied as filler in polymethyl methacrylate (PMMA) matrix polymer composites, and their electromagnetic interference (EMI) shielding performance was investigated. The prepared Ag-RGO/PMMA composites with 3.0 vol% Ag-RGO exhibited an excellent EMI shielding effectiveness (EMI SE) of average 26.8 dB in the 8-12 GHz X-band range, which outperformed the RGO/PMMA composites (18.4 dB) with bare RGO as fillers.

  9. Ag Nanoparticles (Ag NM300K) in the Terrestrial Environment: Effects at Population and Cellular Level in Folsomia candida (Collembola).

    Science.gov (United States)

    Mendes, Luís André; Maria, Vera L; Scott-Fordsmand, Janeck J; Amorim, Mónica J B

    2015-10-01

    The effects of nanomaterials have been primarily assessed based on standard ecotoxicity guidelines. However, by adapting alternative measures the information gained could be enhanced considerably, e.g., studies should focus on more mechanistic approaches. Here, the environmental risk posed by the presence of silver nanoparticles (Ag NM300K) in soil was investigated, anchoring population and cellular level effects, i.e., survival, reproduction (28 days) and oxidative stress markers (0, 2, 4, 6, 10 days). The standard species Folsomia candida was used. Measured markers included catalase (CAT), glutathione reductase (GR), glutathione S-transferase (GST), total glutathione (TG), metallothionein (MT) and lipid peroxidation (LPO). Results showed that AgNO₃ was more toxic than AgNPs at the population level: reproduction EC₂₀ and EC₅₀ was ca. 2 and 4 times lower, respectively. At the cellular level Correspondence Analysis showed a clear separation between AgNO₃ and AgNP throughout time. Results showed differences in the mechanisms, indicating a combined effect of released Ag⁺ (MT and GST) and of AgNPs (CAT, GR, TG, LPO). Hence, clear advantages from mechanistic approaches are shown, but also that time is of importance when measuring such responses. PMID:26473892

  10. 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.

  11. 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.

  12. Modeling the AgInSbTe Memristor

    Directory of Open Access Journals (Sweden)

    J. Yu

    2015-09-01

    Full Text Available The AgInSbTe memristor shows gradual resistance tuning characteristics, which makes it a potential candidate to emulate biological plastic synapses. The working mechanism of the device is complex, and both intrinsic charge-trapping mechanism and extrinsic electrochemical metallization effect are confirmed in the AgInSbTe memristor. Mathematical model of the AgInSbTe memristor has not been given before. We propose the flux-voltage controlled memristor model. With piecewise linear approximation technique, we deliver the flux-voltage controlled memristor model of the AgInSbTe memristor based on the experiment data. Our model fits the data well. The flux-voltage controlled memristor model and the piecewise linear approximation method are also suitable for modeling other kinds of memristor devices based on experiment data.

  13. Communication: UV photoionization of cytosine catalyzed by Ag+

    International Nuclear Information System (INIS)

    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. 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.

  15. 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.

  16. Preparation of Ag/HBP/PAN Nanofiber Web and Its Antimicrobial and Filtration Property

    Directory of Open Access Journals (Sweden)

    Li-Rong Yao

    2016-01-01

    Full Text Available To widen the application of nanofibers web in the field of medical health materials, a new Ag/amino-terminated hyperbranched polymer (HBP/polyacrylonitrile (PAN nanofiber web with excellent antimicrobial activity and filtration property was produced with Ag/HBP dispersion solution and PAN nanofiber. Ag/HBP dispersion solution was prepared with HBP as reducer and stabilizer, and Ag/HBP/PAN nanofiber was prepared by modifying electrospun PAN nanofiber with Ag/HBP aqueous solution. The characterization results showed that spherical Ag nanoparticles were prepared and they had a narrow distribution in HBP aqueous solution. The results of Ag/HBP/PAN nanofiber characterized with SEM and EDS showed that the content of silver nanoparticles on the surface of PAN nanofiber was on the increase when the treating temperature rose. The bacterial reduction rates of HBP-treated PAN nanofiber against S. aureus and E. coli were about 89%, while those of the Ag/HBP/PAN nanofiber against S. aureus and E. coli were 99.9% and 99.96%, respectively, due to the cooperative effects from the amino groups in HBP and Ag nanoparticles. Moreover, the small pores and high porosity in Ag/HBP/PAN nanofiber web resulted in high filtration efficiency (99.9% for removing smaller particles (0.1 μm~0.7 μm, which was much higher than that of the gauze mask.

  17. AgII doped MIL-101 and its adsorption of iodine with high speed in solution

    Science.gov (United States)

    Mao, Ping; Qi, Bingbing; Liu, Ying; Zhao, Lei; Jiao, Yan; Zhang, Yi; Jiang, Zheng; Li, Qiang; Wang, Jinfeng; Chen, Shouwen; Yang, Yi

    2016-05-01

    In order to improve the adsorption speed of iodine from water, MIL-101 with extra-large specific surface area (3054 m2/g) was chosen as a base material, and then, Ag was doped into MIL-101 to enhance its adsorption capacity through an incipient-wetness impregnation method. With the characterization of SEM-EDS, TEM, XRD, XPS, TGA, IR, and BET techniques, the resulting Ag was identified to be stay in the framework of MIL-101 stably in the form of AgII (generally, AgII cation is not stable). However, after the adsorption of I- anions, AgII stay in the cages of MIL-101 in the form of AgI/AgI3. It is important to note that, all adsorbents show high adsorption speed of iodine in solution. The equilibrium adsorption time of the adsorbents were acquired by only a few minutes, which can be attributed to its large BET surface area. An interesting note is that, when the doping amount of Ag is less than 9%, the iodine anions adsorption capacity of Ag@MIL-101 is greater than its theoretical adsorption capacity. It shows that both physical adsorption and chemical adsorption are existed in the adsorption process. This study hopefully leads to a new and highly efficient Ag-based adsorbent for iodide adsorb from solutions.

  18. Ag@AgCl-TiO2-粉煤灰微珠复合光催化剂的制备及其可见光光催化性能%Preparation of Ag@AgCl-TiO2-Flyash Microspheres Composite Photocatalyst and Its Photocatalytic Property under Visible Light

    Institute of Scientific and Technical Information of China (English)

    郭凌坤; 吕珺; 周嵩; 汪冬梅; 徐光青; 郑治祥; 吴玉程

    2012-01-01

    Ag@AgCl nanoparticles were loaded on the surface of flyash microspheres (FMS) by ion-exchange method to prepare Ag@AgCl-FMS composite support, then nano-TiO2 thin film was coated on it by hydrolysis precipitation with TiCl4 solution as precursor. After annealing at 500℃ for 2 h, the Ag@AgCl-FMS-TiO2 composite photocatalyst was obtained. Its microstructure, crystalline structure and photocatalytic properties under visible light were characterized. The results show that the TiO2 thin film on the substrate is uniform and complete. After calcining at 500℃, the material contains of 90% anatase phase and 10% rutile. The composite modified by Ag@AgCl nanoparticles exhibits high photocatalytic activity under visible light, which is caused by the surface plasmon resonance effect of Ag@AgCl. The degradation rate of methyl orange solution can reach 99% after 80 min irradiation under 250 W metal halide lamp. The photocatalyst also shows great stability. Repeated experiments show that the degradation rate of methyl orange solution can still reach 85% after 5 times of using.%采用离子交换法在粉煤灰微珠(FMS)表面沉积Ag@AgCl纳米颗粒,制备Ag@AgCl-FMS复合基底,采用水解-沉淀工艺,以TiCl4为钛源在复合基底表面再包覆纳米TiO2薄膜,经500℃煅烧2h后得到Ag@AgCl- FMS-TiO2复合光催化剂.对材料微观形貌、晶体结构、可见光光催化性能进行了表征与测试.结果表明,复合基底表面包覆的TiO2薄膜均匀完整.500℃煅烧后的物相为90%锐钛矿型TiO2和10%金红石型TiO2.复合催化剂料在Ag@AgCl等离子共振效应的作用下,表现出明显的可见光响应,经可见光照射80 min后对甲基橙的降解率达99%,5次重复使用对甲基橙的降解率保持在85%.

  19. Multifunctional Fe{sub 3}O{sub 4}@C@Ag hybrid nanoparticles: Aqueous solution preparation, characterization and photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Hongxia [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Niu, Helin, E-mail: niuhelin@ahu.edu.cn [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Li, Ping; Tao, Zhiyin; Mao, Changjie; Song, Jiming; Zhang, Shengyi [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China)

    2013-07-15

    Highlights: ► Ag-loaded Fe{sub 3}O{sub 4}@C magnetic-optical bifunctional materials have been investigated. ► The magnetism was studied at the room temperature. ► The photocatalytic activity was evaluated under visible light irradiation. ► Ag-loaded Fe{sub 3}O{sub 4}@C nanocomposites show superior magnetism and photocatalytic activity. ► A simple synthetic process was discussed. - Abstract: The paper describes a kind of multifunctional Fe{sub 3}O{sub 4}@C@Ag hybrid nanoparticles, which can be successfully synthesized using a simple route based on directly adsorption and spontaneous reduction of silver ions onto the surface shell of carbon-coated magnetic nanoparticles. The as-prepared samples have been characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectrum, vibrating sample magnetometer (VSM) and UV–vis spectrum (UV–vis). The Ag nanocrystals loaded on the surface shell of carbon-coated magnetic nanoparticles are nearly spherical with an average diameter of 10 nm. And the carbonaceous polysaccharides shell obtained using an glucose hydrothermal reaction act as a role of a bridge between magnetic Fe{sub 3}O{sub 4} core and noble metallic Ag nanocrystals. The as-prepared samples can be used as an effective catalyst for the photodegradation of organic dyes (neutral red) under the exposure of visible light. Results show that the as-prepared samples have a degradation rate of 93.7% for dyes within 30 min, which indicates their high-efficiency and rapid photocatalytic activity.

  20. 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 ...

  1. 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 ...

  2. 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 ...

  3. 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 ...

  4. 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 ...

  5. 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 ...

  6. 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 ...

  7. 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 ...

  8. 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 ...

  9. 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 ...

  10. 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 ...

  11. 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 ...

  12. Spin dynamics simulations at AGS

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-05-23

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

  13. Self-Depolarization Studies on Some Fast Ag+ Ion Conducting Glasses

    Science.gov (United States)

    Agrawal, R. C.; Verma, M. L.; Bhatt, A.

    2002-12-01

    A novel technique based on the dc polarization method is being reported to study polarization/self-depolarization phenomenon in some fast Ag+ ion conducting glass systems viz.: 0.8[0.75AgI: 0.25AgCl]: 0.2[Ag2O: MoO3] & 0.7[0.75AgI: 0.25AgCl]: 0.3[Ag2O: WO3]. These superionic glasses were prepared recently in the present laboratory using an alternate host: "a quenched [0.75AgI: 0.25AgCl] mixed system/solid solution" in place of the traditional host AgI. An extensive investigation on ion transport behavior of these systems has been done which appeared elsewhere in the literature. In the present study, the sample pallet, placed in between two blocking (graphite) electrodes, was initially polarized with the help of an external d. c. potential (~ 0.5 V) for sufficient long time ensuring that the system attained the state of complete polarization. This resulted into a build up of a potential gradient across the two faces of the sample pallet, which can be measured instantly on removal of the external dc potential. This has been be referred to as an 'Instant Peak Potential (Vp)'. The magnitude of 'Vp' gives the quantitative information regarding the number of mobile Ag+ ions present in the system at a given temperature. 'Vp' measurements were carried out extensively on the sample pallets of different thickness as a function of time and temperature. The log Vp - 1/T variations for these systems were found to be almost analogous to log n - 1/T plots, reported earlier.

  14. Enhanced hydrogen evolution from water splitting using Fe-Ni codoped and Ag deposited anatase TiO{sub 2} synthesized by solvothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Tao [School of Chemical Engineering, Northwest University, No. 229 Taibai North Road, Xi’an, Shaanxi 710069 (China); School of Chemistry & Chemical Engineering, Nanjing University, No. 22 Hankou Road, Nanjing, Jiangsu 210093 (China); Liu, Enzhou; Liang, Xuhua [School of Chemical Engineering, Northwest University, No. 229 Taibai North Road, Xi’an, Shaanxi 710069 (China); Hu, Xiaoyun [Department of Physics, Northwest University, No. 229 Taibai North Road, Xi’an, Shaanxi 710069 (China); Fan, Jun, E-mail: fanjun@nwu.edu.cn [School of Chemical Engineering, Northwest University, No. 229 Taibai North Road, Xi’an, Shaanxi 710069 (China)

    2015-08-30

    Graphical abstract: - Highlights: • Fe-Ni/Ag/TiO{sub 2} nanocomposites displayed a higher hydrogen evolution rate. • TiO{sub 2} showed well optical property of light absorption by Fe, Ni and Ag modified. • More surface vacancies on TiO{sub 2} generated by the low cost metal introduced. • The separation rate of photoinduced electro-hole pairs was considerable improved. - Abstract: In this paper, the Fe-Ni co-doped and Ag deposited anatase TiO{sub 2} (Fe-Ni/Ag/TiO{sub 2}) nanocomposites were successfully prepared by a simple one-pot solvothermal approach. The investigations indicated that all as-prepared TiO{sub 2} samples were single anatase phase, and the impurity level was generated due to the Fe{sup 3+} or Ni{sup 2+} being located in the intrinsic band gap of TiO{sub 2}, while the Ag{sup +} ions could be transformed into metallic silver due to the reduction reaction and then loaded onto the surface of TiO{sub 2}. Compared with pure TiO{sub 2}, Fe-Ni/Ag/TiO{sub 2} composites with the sizes of Ag nanoparticles from 1.0 to 3.0 nm displayed the well optical property including higher visible light absorption activity and lower electron-hole pair recombination rate, and its absorption wavelength edge moved remarkably with a red shift to 700 nm. The photocatalytic water splitting was performed to produce H{sub 2} over the samples, and the experimental results indicate that Fe-Ni/Ag/TiO{sub 2} composites presented the highest H{sub 2} evolution rate, it can reach up to 793.86 μmol h{sup −1} g{sub cat}{sup −1} (λ > 400 nm for 6 h, energy efficiency is 0.25%), which was much higher than that of pure TiO{sub 2} for 9.57 μmol h{sup −1} g{sub cat}{sup −1}. In addition, a tentative photocatalytic mechanism is proposed to understand the enhancement mechanism over Fe-Ni codoped and Ag deposited anatase TiO{sub 2}.

  15. Direct in situ activation of Ag0 nanoparticles in synthesis of Ag/TiO2 and its photoactivity

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Ag0 loaded on TiO2 was prepared by a direct in situ electrochemical method. • 5 wt% Ag–TiO2 demonstrated the best photocatalytic degradation of 2-CP. • Isomorphous substitution of Ag with Ti occurred to form Ti−O−Ag bonds. • Ag0 and oxygen vacancies trapped electrons to enhance e–H+ separation. • Substitution of Ag in the TiO2 structure decreased the number of oxygen vacancies. - Abstract: Metallic Ag nanoparticles (Ag0) were successfully activated using a direct in situ electrochemical method before being supported on TiO2. Catalytic testing showed that 5 wt% Ag–TiO2 gave the highest photodegradation (94%) of 50 mg L−1 2-chlorophenol (2-CP) at pH 5 using 0.375 g L−1 catalyst within 6 h, while under similar conditions, 1 wt% and 10 wt% Ag–TiO2 only gave 75% and 78% degradation, respectively. Characterization results illustrated that the photoactivity was affected by the amount of Ag0 and oxygen vacancies which act as an electrons trap to enhance the electron–hole separation. While, the Ag−O−Ti bonds formation reduced the photoactivity. The degradation followed a pseudo-first order Langmuir–Hinshelwood model where adsorption was the controlling step. Study on the effect of scavengers showed that the hole (H+) and hydroxyl radical (OH·) play important roles in the photodegradation. The regenerated photocatalyst was still stable after five cycling runs

  16. Influence of particle coating and matrix constituents on the cloud point extraction efficiency of silver nanoparticles (Ag-NPs) and application for monitoring the formation of Ag-NPs from Ag(+).

    Science.gov (United States)

    Hartmann, Georg; Baumgartner, Tanja; Schuster, Michael

    2014-01-01

    For the quantification of silver nanoparticles (Ag-NPs) in environmental samples using cloud point extraction (CPE) for selective enrichment, surface modification of the Ag-NPs and matrix effects can play a key role. In this work we validate CPE with respect to the influence of different coatings and naturally occurring matrix components. The Ag-NPs tested were functionalized with inorganic and organic compounds as well as with biomolecules. Commercially available NPs and NPs synthesized according to methods published in the literature were used. We found that CPE can extract almost all Ag-NPs tested with very good efficiencies (82-105%). Only Ag-NPs functionalized with BSA (bovine serum albumin), which is a protein with the function to keep colloids in solution, cannot be extracted. No or little effect of environmentally relevant salts, organic matter, and inorganic colloids on the CPE of AgNPs was found. Additionally we used CPE to observe the in situ formation of Ag-NPs produced by the reduction of Ag(+) with natural organic matter (NOM).

  17. Characterizing the economic value of an epithermal Au-Ag ore with Laser Induced Breakdown Spectroscopy (LIBS)

    NARCIS (Netherlands)

    Dalm, M.; Buxton, M.W.N.

    2016-01-01

    LIBS was applied to 19 Au-Ag ore samples to investigate if this technique can be used to distinguish between economic and sub-economic ore either by direct detection of these elements or by using other elements as indicators. However, the Au and Ag grades of the samples are below the detection limit

  18. 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

  19. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

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

  20. Sunlight-Responsive Ag2 S/Ag3 PO4 Composite Preparation and Degradation of Salicylic Acid%太阳光响应型 Ag2S/Ag3PO4复合材料的制备及催化降解水杨酸

    Institute of Scientific and Technical Information of China (English)

    朱遂一; 徐东方; 方帅; 耿直; 杨霞

    2014-01-01

    An efficient sunlight responsive Ag2 S / Ag3 PO4 composite was prepared by co-precipitation method combined with hydrothermal treatment. The morphology, composition, surface physical and chemical property and optical absorption property were characterized by scanning electron microscope(SEM), X-ray powder dif-fraction(XRD), X-ray photoelectron spectroscopy ( XPS) and ultraviolet-visible diffuse reflection ( UV-Vis DR). The 1% Ag2 S / Ag3 PO4 composite has rough surface with smaller particle size less than 0. 8 μm and wider bandgap(2. 24 eV) compared to Ag3 PO4 . The photocatalytic activity of Ag2 S / Ag3 PO4 was evaluated by degradation of salicylic acid which is a typical material in pharmaceuticals and personal care products(PPCPs) and harmful to human health and ecosystems. The results show that Ag2 S / Ag3 PO4 composite doped 1% Ag2 S with hydrothermal treated at 120 ℃ for 4 h exhibits excellent salicylic acid degradation efficiency reached to 88. 2% under simulated sunlight irradiation for 60 min and the light source current intensity is 15 A, when Ag2 S / Ag3 PO4 used 0. 15 g, the initial concentration of salicylic acid is 10 mg / L and pH is 6. 0, respectively. The contribution of various parameters for the enhanced photocatalytic activities is revealed in detail. The pri-mary reasons for the increased simulated sunlight photocatalyst activity are contribution to the perfect cubic crystal structure, smaller particle size and broaden the visible spectral response. Doping sulfide is benefit to absorb sunlight and separate the electron-hole effectively.%以 AgNO3, Na2 HPO4和硫粉为原料,采用共沉淀-水热法合成了具有太阳光响应型 Ag2 S/ Ag3 PO4复合材料,运用扫描电子显微镜(SEM)、 X 射线粉末衍射(XRD)、 X 射线光电子能谱(XPS)和紫外-可见漫反射(UV-Vis DR)光谱等方法对样品进行了表征,并在模拟太阳光条件下,考察了 Ag2 S/ Ag3 PO4对水杨酸的光催化降解效率.结果表明,与 Ag3 PO4

  1. Molecular-dynamics study of ionic motions and neutron inelastic scattering in α-AgI

    Science.gov (United States)

    Chiarotti, Guido L.; Jacucci, G.; Rahman, A.

    1986-11-01

    Contrary to the current interpretation of inelastic-neutron-scattering data on α-AgI, molecular-dynamics calculations show that inelastic neutron scattering is dominated by coherent scattering from Ag+ ions. The calculations agree with the available data. Ag+ ions diffuse by jumps between tetrahedral sites, the consequences being in complete accord with the Chudley-Elliot model only if the full geometrical complexity of these sites is included. Phonon modes due to I- motions are predicted for certain wave vectors.

  2. Study of boron implantation in Ag-Si layer structures

    Energy Technology Data Exchange (ETDEWEB)

    Pelikan, L. (Ceske Vysoke Uceni Technicke, Prague (Czechoslovakia). Fakulta Elektrotechnicka); Rybka, V.; Krejci, P. (Tesla, Prague (Czechoslovakia). Vyzkumny Ustav pro Sdelovaci Techniku); Hnatowicz, V.; Kvitek, J. (Ustav Jaderneho Vyzkumu CSKAE, Rez (Czechoslovakia))

    1982-07-16

    The implanted boron depth profiles in samples comprising Si wafers covered with Ag films of various thicknesses are determined experimentally as well as by Monte-Carlo simulation. A complex shape of depth profiles is revealed, which is well reproduced by the calculation.

  3. Slow positron studies on single crystals of Ag(100), Ag(111) and Cu(111)

    International Nuclear Information System (INIS)

    Monoenergetic positrons were employed to examine positronium formation as a function of sample temperature (300 to 1200 K) and incident energy (0 to 5 keV) on Ag(100), Ag(111) and Cu(111) surfaces with submonolayer contamination. In these metals at the higher temperatures, positronium formation becomes the dominant process. A one-dimensional diffusion model is fit to the data as a function of incident energy. Th positronium fraction is found to be an activated process and is identified as detrapping from a surface state and an estimate of the depth of this trap is extracted. The diffusion length is found to be temperature independent before the onset of vacancy trapping. At the higher temperatures vacancy trapping is observed by the decrease in the positron diffusion length at the higher incident voltages. A vacancy formation energy is extracted from the data and is generally lower than the accepted bulk values. 18 references

  4. Toxic effects and bioaccumulation of nano-, micron- and aqueous-Ag in the estuarine polychaete, Nereis (Hediste) diversicolor

    DEFF Research Database (Denmark)

    cong, Yi

    diameter and zeta potential was only carried out on nano-Ag in stock suspension (deionized water). However, we observed a clear difference of particle sizes between the manufacturer’s information and what we measured for both nano- and micron-Ag samples. In toxicity experiment I, toxic effects of sediment...... size of particles, or other characteristics (i.e., ion release). The nominal concentrations used in all exposure scenarios were 0, 1, 5, 10, 25 and 50 µg Ag/g dry weight (dw) sediment. In toxicity experiment II, toxic effects of sediment-spiked nano-Ag20, nano-Ag80 or aqueous-Ag (AgNO3) on N...... concern about the fate and potential risks of nanosilver for the aquatic environment after its eventual release via wastewater discharges. In this thesis, dispersion and stability tests of commercially available nano (particles in two media (deionized water vs...

  5. Synthesis, characterization and application of ZnO-Ag as a nanophotocatalyst for organic compounds degradation, mechanism and economic study.

    Science.gov (United States)

    Mohammadzadeh, S; Olya, M E; Arabi, A M; Shariati, A; Khosravi Nikou, M R

    2015-09-01

    The current work deals with ZnO-Ag nanocomposites (in the wide range of x in the Zn1-xO-Agx chemical composition) synthesized using microwave assisted solution combustion method. The structural, morphological and optical properties of the samples were characterized by XRD (X-ray diffraction), FTIR (Fourier transform infrared spectrometry), SEM (scanning electron microscopy technique), EDX (energy dispersive X-ray spectrum), ICP (inductively coupled plasma technique), TEM (transmission electron microscopy), BET (Brunauer-Emmett-Teller method), UV-Vis (ultraviolet-visible spectrophotometer) and photoluminescence spectrophotometer. The photocatalytic activity of the ZnO-Ag was investigated by photo-degradation of Acid Blue 113 (AB 113) under UV illumination in a semi-batch reactor. This experiment showed that ZnO-Ag has much more excellent photocatalytic properties than ZnO synthesized by the same method. The enhanced photocatalytic activity was due to the decrease in recombination of photogenerated electron-holes. The results showed the improvement of ZnO photocatalytic activity and there is an optimum amount of Ag (3.5mol%) that needs to be doped with ZnO. The effect of operating parameters such as pH, catalyst dose and dye concentration were investigated. The reaction byproducts were identified by LC/MS (liquid chromatography/mass spectrometry) analysis and a pathway was proposed as well. Kinetic studies indicated that the decolorization process follows the first order kinetics. Also, the degradation percentage of AB 113 was determined using a total organic carbon (TOC) analyzer. Additionally, cost analysis of the process, the mechanism and the role of Ag were discussed. PMID:26354709

  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. 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.

  8. Stabilization and immune response of HBsAg encapsulated within poly(lactic-co-glycolic acid) microspheres using HSA as a stabilizer.

    Science.gov (United States)

    Xu, Wenjuan; He, Jintian; Wu, Guanghao; Xiong, Fangfang; Du, Huijuan; Wang, Gaizhen

    2015-12-30

    The aim of this study was to prepare poly(lactic-co-glycolic acid) (PLGA) microspheres containing hepatitis B virus surface antigen (HBsAg) using human serum albumin (HSA) as a stabilizer. Lyophilization and emulsification of HBsAg solution with dichloromethane caused a considerable loss of HBsAg antigenicity. Thus, the effects of HSA and trehalose on HBsAg recovery during lyophilization and emulsification were investigated. Adding HSA to HBsAg solutions significantly improved antigen recovery to >90% during lyophilization and emulsification. The effects of co-encapsulated HSA on the characteristics of the PLGA microspheres and stability of HBsAg released from the microspheres were also investigated. The in vitro release test showed that HBsAg was released from the PLGA microspheres continuously over seventy days. A large amount of released HBsAg was inactive without co-encapsulation of HSA. On the contrary, with HSA co-encapsulation, the released HBsAg retained approximately 90% of its antigenicity. The single injection of the HBsAg-HSA-loaded PLGA microspheres in rats resulted in higher anti-HBsAg IgG and Th1 cytokine levels than the single injection of the HBsAg-loaded microspheres or two injections of the conventional aluminum-adjuvanted HBsAg vaccine. Based on these findings, the HBsAg-HSA-loaded PLGA microspheres could be an effective carrier for HBsAg and form a promising depot system.

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

    Science.gov (United States)

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

    2013-07-01

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

  10. Mechanism of strong visible light photocatalysis by Ag2O-nanoparticle-decorated monoclinic TiO2(B) porous nanorods

    Science.gov (United States)

    Paul, Kamal Kumar; Ghosh, Ramesh; Giri, P. K.

    2016-08-01

    We report on the ultra-high rate of photodegradation of organic dyes under visible light illumination on Ag2O-nanoparticle-decorated (NP) porous pure B-phase TiO2 (TiO2(B)) nanorods (NRs) grown by a solvothermal route. The as-grown TiO2(B) NRs are found to be nanoporous in nature and the Ag2O NPs are uniformly decorated over its surface, since most of the pores work as nucleation sites for the growth of Ag2O NPs. The effective band gap of the TiO2(B)/Ag2O heterostructure (HS), with a weight ratio of 1:1, has been significantly reduced to 1.68 eV from the pure TiO2(B) band gap of 2.8 eV. Steady state and time-resolved photoluminescence (PL) studies show the reduced intensity of visible PL and slower recombination dynamics in the HS samples. The photocatalytic degradation efficiency of the TiO2(B)/Ag2O HS has been investigated using aqueous methyl orange and methylene blue as reference dyes under visible light (390-800 nm) irradiation. It is found that photodegradation by the TiO2(B)/Ag2O HS is about one order of magnitude higher than that of bare TiO2(B) NRs and Ag2O NPs. The optimized TiO2(B)/Ag2O HS exhibited the highest photocatalytic efficiency, with 88.2% degradation for 30 min irradiation. The corresponding first order degradation rate constant is 0.071 min-1, which is four times higher than the reported values. Furthermore, cyclic stability studies show the high stability of the HS photocatalyst for up to four cycles of use. The major improvement in photocatalytic efficiency has been explained on the basis of enhanced visible light absorption and band-bending-induced efficient charge separation in the HS. Our results demonstrate the long-term stability and superiority of the TiO2(B)/Ag2O HS over the bare TiO2(B) NRs and other TiO2-based photocatalysts for its cutting edge application in hydrogen production and environmental cleaning driven by solar light photocatalysis.

  11. Differential protein expression in mussels Mytilus galloprovincialis exposed to nano and ionic Ag

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Tânia; Pereira, Catarina G.; Cardoso, Cátia; Bebianno, Maria João, E-mail: mbebian@ualg.pt

    2013-07-15

    protein involved in cytoskeleton and cell structure (paramyosin), while exposure to Ag{sup +} had a strong influence in one protein related to stress response (putative c1q domain containing protein) and two proteins involved in cytoskeleton and cell structure (actin and α-tubulin). Protein identification showed that Ag NPs toxicity is mediated by oxidative stress-induced cell signalling cascades (including mitochondria and nucleus) that can lead to cell death. This toxicity represents the cumulative effect of Ag{sup +} released from the particles and other properties as particle size and surface reactivity. This study helped to unravel the molecular mechanisms that can be associated with Ag NPs toxicity; nevertheless, some additional studies are required to investigate the exact interaction between these NPs and cellular components.

  12. Establishment and identification of OVA-HBsAg transgenic mice regulated by Cre recombinase

    Directory of Open Access Journals (Sweden)

    Xiu-mei LI

    2015-06-01

    Full Text Available Objective To breed OVA-HBsAg transgenic mice regulated by Cre recombinase in order to provide a better animal model for the study of HBV prevention and therapy. Methods The OVA-HBsAg transgenic mice were generated by microinjection of OVA-HBsAg gene with LoxP sites into the pronucleus of C57BL/6J×DBA zygotes. Pups of F1 OVA-HBsAg female mice cross-fertilized with Alb-Cre male mice were assayed for the expression of HBsAg induced by Cre recombinase. PCR, ELISA and immunohistochemical methods were used to detect the integration and expression of HBsAg gene and Cre gene in the transgenic mice. Results 491 fertilized eggs were injected and a total of 337 survived. The survival rate of injection was 68.6%. 29 F0 pups were produced with 4 PCR-positive mice, and the positive rate was 13.8%. Up to now, F4 pups were obtained. The positive rates from F1 to F4 were 27.5%, 32.0%, 22.9% and 25.0%, respectively. No HBsAg-positive mice were found among these pups. Furthermore, among 16 pups of F1 OVA-HBsAg female mice crossed with Alb-Cre male mice, 6 were positive for both HBsAg and Cre as detected by PCR. There were 2 pups showed positive HBsAg by ELISA assay. The expression rate of HBsAg after Cre recombinase induction was 33.3%. Conclusion OVA-HBsAg transgenic mice has been reproduced successfully, and it can be stably passaged. Cre recombinase can induce the expression of HBsAg in vivo. DOI: 10.11855/j.issn.0577-7402.2015.05.08

  13. Microstructure and properties of Bi-2223/Ag/Ni tapes

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    To reduce the production cost of Bi-2223 superconducting tapes, Bi-2223/Ag/Ni tapes were fabricated by the powder-in-tube process. The effect of heat treatment on the microstructure and critical current of the Bi-2223/Ag/Ni tapes were studied. The phase compositions of the samples were characterized using XRD. The microstructure was observed using SEM. Experimental results indicate that higher temperature is more conducive to the formation of Bi-2223 phase at an atmosphere of 8.5% O 2 . After the two-step h...

  14. EDDY CURRENT EFFECT OF THE BNL-AGS VACUUM CHAMBER ON THE OPTICS OF THE BNL-AGS SYNCHROTRON.

    Energy Technology Data Exchange (ETDEWEB)

    TSOUPAS,N.; AHRENS,L.; BROWN,K.A.; GLENN,J.W.; GARDNER,K.

    1999-03-29

    During the acceleration cycle of the AGS synchrotron, eddy currents are generated within the walls of the vacuum chambers of the AGS main magnets. The vacuum chambers have elliptical cross section, are made of inconel material with a wall thickness of 2 mm and are placed within the gap of the combined-function main magnets of the AGS synchrotron. The generation of the eddy currents in the walls of the vacuum chambers, creates various magnetic multipoles, which affect the optics of the AGS machine. In this report these magnetic multipoles are calculated for various time interval starting at the acceleration cycle, where the magnetic field of the main magnet is {approx}0.1 T, and ending before the beam extraction process, where the magnetic field of the main magnet is almost constant at {approx}1.1 T. The calculations show that the magnetic multipoles generated by the eddy-currents affect the optics of the AGS synchrotron during the acceleration cycle and in particular at low magnetic fields of the main magnet. Their effect is too weak to affect the optics of the AGS machine during beam extraction at the nominal energies.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-15

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

  16. Comparative study of methods of detection of hepatitis ′B′ surface antigen (HBsAg.

    Directory of Open Access Journals (Sweden)

    Parab V

    1989-04-01

    Full Text Available The serum samples were collected from 52 patients of acute viral hepatitis and 235 hospital staff from Kasturba Hospital for Infectious Diseases. HBsAg was detected in their sera by counter-immuno-electrophoresis (CIEP, reverse passive hemogglutination (RPHA and by micro-enzyme-linked-immunosorbent assay (ELISA technique. Among the patients, HBsAg was detected in 12 cases (23% by CIEP, in 18 cases (34% by RPHA and in 23 patients (45% by ELISA. In the hospital staff, HBsAg was detected in 4 samples (1.7% by CIEP, in 8 samples (3.5% by RPHA and in 32 samples (13.5% by ELISA. Thus ELISA was found to be the most sensitive technique in detecting HBsAg.

  17. Synthesis of a new molecularly imprinted polymer for sorption of the silver ions from geological and antiseptic samples for determination by flame atomic absorption spectrometry.

    Science.gov (United States)

    Hashemi-Moghaddam, Hamid; Yahyazadeh, Faegheh; Vardini, Mohammad Taghi

    2014-01-01

    A new molecularly imprinted polymer (MIP) was synthesized using methacrylic acid (functional monomer), ethylene glycol dimethacrylate (crosslinker), 2,2'-azobisisobutironitril (initiator), silver (Ag) dithizone complex (template), and chloroform (porogenic solvent). This process was a noncovalent, bulk, thermal radical-polymerization. To compare the performance of this polymer, control polymer (nonimprinted polymer) was prepared under well-defined conditions without the use of a template. Extraction experiments were performed on the MIP and a nonimprinted polymer. Then, various parameters were optimized, such as pH, time, concentration of sample, and type of eluent for elution of Ag from polymer. In addition, interfering effects were investigated on the absorption of Ag by the MIP. This polymer was used for the rapid extraction and preconcentration of Ag from an antiseptic and geological sample. Finally, the amount of Ag was measured by flame atomic absorption spectrometry after preconcentration by the synthesized MIP, and results were compared with a direct inductively coupled plasma method. The results showed high performance of this method in preconcentration of Ag. PMID:25902996

  18. Electrocatalytic simultaneous determination of ascorbic acid, uric acid and L-Cysteine in real samples using quercetin silver nanoparticles-graphene nanosheets modified glassy carbon electrode

    Science.gov (United States)

    Zare, Hamid R.; Jahangiri-Dehaghani, Fahime; Shekari, Zahra; Benvidi, Ali

    2016-07-01

    By immobilizing of quercetin at the surface of a glassy carbon electrode modified with silver nanoparticles and graphene nanosheets (Q-AgNPs-GNs-GCE) a new sensor has been fabricated. The cyclic voltammogram of Q-AgNPs-GNs-GCE shows a stable redox couple with surface confined characteristics. Q-AgNPs-GNs-GCE demonstrated a high catalytic activity for L-Cysteine (L-Cys) oxidation. Results indicated that L-Cys peak potential at Q-AgNPs-GNs-GCE shifted to less positive values compared to GNs-GCE or AgNPs-GCE. Also, the kinetic parameters such as the electron transfer coefficient,, and the heterogeneous electron transfer rate constant, k‧, for the oxidation of L-Cys at the Q-AgNPs-GNs-GCE surface were estimated. In differential pulse voltammetric determination, the detection limit of L-Cys was obtained 0.28 μM, and the calibration plots were linear within two ranges of 0.9-12.4 μM and 12.4-538.5 μM of L-Cys. Also, the proposed modified electrode is used for the simultaneous determinations of ascorbic acid (AA), uric acid (UA), and L-Cys. Finally, this study has demonstrated the practical analytical utility of the sensor for determination of AA in vitamin C tablet, L-Cys in a milk sample and UA in a human urine sample.

  19. Self-healing of cracks in Ag joining layer for die-attachment in power devices

    Science.gov (United States)

    Chen, Chuantong; Nagao, Shijo; Suganuma, Katsuaki; Jiu, Jinting; Zhang, Hao; Sugahara, Tohru; Iwashige, Tomohito; Sugiura, Kazuhiko; Tsuruta, Kazuhiro

    2016-08-01

    Sintered silver (Ag) joining has attracted significant interest in power devices modules for its ability to form stable joints with a porous interconnection layer. A function for the self-healing of cracks in sintered porous Ag interlayers at high temperatures is discovered and reported here. A crack which was prepared on a Ag joining layer was closed after heating at 200 °C in air. The tensile strength of pre-cracked Ag joining layer specimens recovers to the value of non-cracked specimens after heating treatment. Transmission electron microscopy (TEM) was used to probe the self-healing mechanism. TEM images and electron diffraction patterns show that a large quantity of Ag nanoparticles formed at the gap with the size less than 10 nm, which bridges the crack in the self-healing process. This discovery provides additional motivation for the application of Ag as an interconnection material for power devices at high temperature.

  20. Particle placement and sheet topological control in the fabrication of Ag-hexaniobate nanocomposites.

    Science.gov (United States)

    Adireddy, Shiva; Rostamzadeh, Taha; Carbo, Cecilia E; Wiley, John B

    2015-01-01

    Synthetic methods are demonstrated that allow for the fabrication of Ag-hexaniobate nanocomposites with directed nanoparticle (NP) placement and nanosheet morphological control. The solvothermal treatment of exfoliated nanosheets (NSs) in the presence of Ag NPs leads to a high yield of Ag nanocomposites. This approach is quite flexible and, with control of time and temperature, can be used to produce nanocomposites with specific architectures; Ag NPs can be attached to nanosheets, attached to the surfaces of nanoscrolls, or at higher temperatures, captured within nanoscrolls to form nanopeapod (NPP) structures. The decorated nanosheets and nanoscrolls show surface plasmon resonance (SPR) maxima similar to that of free Ag NPs, while the Ag NPPs exhibit a red shift of about 10 nm. PMID:25531945

  1. AG, TL, and IRSL dosimetric properties in X-ray irradiated HPHT diamond crystals

    Energy Technology Data Exchange (ETDEWEB)

    Gil-Tolano, M.I. [Programa de Posgrado, Departamento de Investigacion en Fisica, Universidad de Sonora, A. P. 5-088, Hermosillo, Sonora, 83190, Mexico (Mexico); Melendrez, R.; Lancheros-Olmos, J.C.; Soto-Puebla, D.; Chernov, V.; Pedroza-Montero, M.; Barboza-Flores, M. [Departamento de Investigacion en Fisica, Universidad de Sonora, A. P. 5-088, Hermosillo, Sonora, 83190, Mexico (Mexico); Castaneda, B. [Departamento de Fisica, Universidad de Sonora, Blvd. Luis Encinas y Rosales S/N, Hermosillo, Sonora, 83000, Mexico (Mexico)

    2014-10-15

    HPHT diamonds have been studied for several years for their potential in different applications. In previous studies it has been found that the thermoluminescence (TL) glow curves of ''as-grown'' HPHT diamonds are non-reproducible. In this work, we study the afterglow (AG), thermoluminescent (TL), and optically stimulated luminescence (OSL) response of commercial samples of synthetic HPHT type-Ib diamond crystals exposed to X-ray irradiation (0.75 mA, 35 kV) at a dose rate of 0.624 Gy/s, after a high gamma ({sup 60}Co) dose irradiation of 500 kGy followed by a thermal treatment at 1073 K for 1 h in nitrogen atmosphere. Deconvolution of the TL glow curves shows four peaks, located around 379, 509, 561, and 609 K. The crystals exhibit evident AG recorded for 300 s immediately after X-ray irradiation, due to the thermal emptying of the traps responsible for the low-temperature TL peaks (below 400 K). The stimulation of irradiated crystals with 870-nm light, creates pronounced OSL and destroys all TL peaks with the exception of the high-temperature peak at 609 K. The dose responses of the integrated AG, TL, and OSL are linear in the range of 0.6-5 Gy and saturated at higher doses. The reproducibility of AG, TL, and OSL measurements is about 5%. The fading in the first hour of storage in dark conditions at RT of TL signal of HPHT diamond is mainly associated to the emptying of the traps responsible for the 379-K TL peaks. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Cellular Energy Allocation to Assess the Impact of Nanomaterials on Soil Invertebrates (Enchytraeids: The Effect of Cu and Ag

    Directory of Open Access Journals (Sweden)

    Susana I. L. Gomes

    2015-06-01

    Full Text Available The effects of several copper (Cu and silver (Ag nanomaterials were assessed using the cellular energy allocation (CEA, a methodology used to evaluate the energetic status and which relates with organisms’ overall condition and response to toxic stress. Enchytraeus crypticus (Oligochatea, was exposed to the reproduction effect concentrations EC20/50 of several Cu and Ag materials (CuNO3, Cu-Field, Cu-Nwires and Cu-NPs; AgNO3, Ag NM300K, Ag-NPs Non-coated and Ag-NPs PVP-coated for 7 days (0-3-7d. The parameters measured were the total energy reserves available (protein, carbohydrate and lipid budgets and the energy consumption (Ec integrated to obtain the CEA. Results showed that these parameters allowed a clear discrimination between Cu and Ag, but less clearly within each of the various materials. For Cu there was an increase in Ec and protein budget, while for Ag a decrease was observed. The results corroborate known mechanisms, e.g., with Cu causing an increase in metabolic rate whereas Ag induces mitochondrial damage. The various Cu forms seem to activate different mechanisms with size and shape (e.g., Cu-NPs versus Cu-Nwires, causing clearly different effects. For Ag, results are in line with a slower oxidation rate of Ag-NMs in comparison with Ag-salt and hence delayed effects.

  3. Synthesis, Antibacterial and Thermal Studies of Cellulose Nanocrystal Stabilized ZnO-Ag Heterostructure Nanoparticles

    Directory of Open Access Journals (Sweden)

    Mohd Zobir Hussein

    2013-05-01

    Full Text Available Synthesis of ZnO-Ag heterostructure nanoparticles was carried out by a precipitation method with cellulose nanocrystals (CNCs as a stabilizer for antimicrobial and thermal studies. ZnO-Ag nanoparticles were obtained from various weight percentages of added AgNO3 relative to Zn precursors for evaluating the best composition with enhanced functional properties. The ZnO-Ag/CNCs samples were characterized systematically by TEM, XRD, UV, TGA and DTG. From the TEM studies we observed that ZnO-Ag heterostructure nanoparticles have spherical shapes with size diameters in a 9–35 nm range. The antibacterial activities of samples were assessed against the bacterial species Salmonella choleraesuis and Staphylococcus aureus. The CNC-stabilized ZnO-Ag exhibited greater bactericidal activity compared to cellulose-free ZnO-Ag heterostructure nanoparticles of the same particle size. The incorporation of ZnO-Ag hetreostructure nanoparticles significantly increased the thermal stability of cellulose nanocrystals.

  4. Isothermal decomposition kinetics in the Cu-9%Al-4%Ag alloy

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-07-28

    The influence of 4 wt.%Ag addition on the isothermal decomposition kinetics of the {beta}' phase in the Cu-9 wt.%Al alloy was studied by microhardness measurements, optical and scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, and X-ray diffractometry. The results showed that the presence of Ag decreases the {beta}'{yields}({alpha}+{gamma}{sub 1}) decomposition reaction rate in the Cu-9%Al-4%Ag alloy, an effect that may be associated to the {gamma}{sub 1} phase which catalyses the Ag precipitation, making it faster than the decomposition reaction, and thus, stabilizing the martensitic phase.

  5. Optical Limiting Properties of Ag-Cu Metal Alloy Nanoparticles Analysis by using MATLAB

    International Nuclear Information System (INIS)

    Ag-Cu alloy nanoparticles were formed by sequential ion implantation (Ag and Cu) in silica using a metal vapor vacuum arc (MEVVA) ion source. Third-order nonlinear optical properties of the nanoparticles were measured at 1064 nm excitations using the Z-scan technique. Curve fitting analysis, based on the MATLAB features for Ag-Cu alloy nanoparticle optical limiting experiments, is used. The results show that Ag-Cu alloy nanoparticles display a refractive optical limiting effect at 1064nm. (condensed matter: structure, mechanical and thermal properties)

  6. Effects of Excess Cu Addition on Photochromic Properties of AgCl-Urethane Resin Composite Films

    Directory of Open Access Journals (Sweden)

    Hidetoshi Miyazaki

    2013-01-01

    Full Text Available AgCl-resin photochromic composite films were prepared using AgNO3, HCl-EtOH, CuCl2 ethanol solutions, and a urethane resin as starting materials. The AgCl particle size in the composite films, which was confirmed via TEM observations, was 23–43 nm. The AgCl composite films showed photochromic properties: coloring induced by UV-vis irradiation and bleaching induced by cessation of UV-vis irradiation. The coloring and bleaching speed of the composite film increases with increasing CuCl2 mixing ratio.

  7. Bicomponent AgCl/PVP nanofibre fabricated by electrospinning with gel–sol method

    Indian Academy of Sciences (India)

    Jie Bai; Yaoxian Li; Lei Sun; Chaoqun Zhang; Qingbiao Yang

    2009-04-01

    A new series of poly(vinyl pyrrolidone) (PVP) and silver chloride nanoparticles (AgCl) composite fibres have been synthesized by electrospinning and gel–sol technology. We used sol–gel process to prepare AgCl nanoparticles in the PVP solution, and then the solutions were electrospun to obtain AgCl/PVP composite nanofibres. The final products were thoroughly characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and field-emission scanning electron microscopy (FESEM), which showed the formation of AgCl nanoparticles/PVP composite nanofibres.

  8. 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.

  9. Novel Ag/Kaolin Nanocomposite as Adsorbent for Removal of Acid Cyanine 5R from Aqueous Solution

    OpenAIRE

    Saeedeh Hashemian; Mohammad Reza Shahedi

    2013-01-01

    Ag/kaolin nanocomposite was prepared by reduction of Ag+ ion with ethanol at alkaline condition on kaolin surface. Nanocomposite was characterized by FTIR, XRD, TEM, and BET methods. Results showed the Ag/kaolin composite has particle size 50 nm. The surface area was increased from kaolin to Ag/kaolin from 1.0215 to 7.409 m2 g−1, respectively. Ag/kaolin nanocomposite was used for adsorption of acid cyanine 5R (AC5R) from aqueous solution. The effect of parameters such as contact time, pH, an...

  10. Synthesis of Ag@TiO2 core-shells using a rapid microwave irradiation and study of their nonlinear optical properties

    Science.gov (United States)

    Karimipour, M.; Ebrahimi, M.; Abafat, Z.; Molaei, M.

    2016-07-01

    Ag@TiO2 core-shells were synthesized by employing oleylamine as capping agent and using a rapid microwave method. The shell growth was optimized first based on the variation of oleylamine content in the reaction solution. Thereafter the shell thickness was varied just by varying titanium isopropoxide (TiTP) with 25, 50, 100 and 200 μl as TiO2 precursor. The prepared core-shells were characterized by means of XRD, FTIR spectroscopy, transmission electron microscopy, and UV-Vis spectroscopy. XRD analysis revealed a cubic crystal structure for Ag and Anatase phase for TiO2. TEM images clearly indicated that the size of Ag core is roughly 15 nm and with the increase of TiTP, the shell thickness increases and varies between 5 nm and 15 nm. UV-Vis spectroscopy indicated that the plasmon resonance of Ag nanoparticles shifts from 407 nm up to 454 nm with the increase of TiTP precursor. Using a low power laser diode at a 532 nm wavelength, the magnitude and the sign of the nonlinear refractive index were determined by the Z-scan technique and Sheik-Bahae model. The results show that the enhancement of nonlinear optical properties originates from the quality of TiO2 shell growth. The highest nonlinearity belongs to the sample synthesized with 100 μlit TiTP. Generally all the prepared Ag@TiO2 core-shells show both saturable and reverse saturable absorption. They exhibit also a considerable nonlinear absorption and nonlinear refractive index ranging from -4.21 × 10-7 to -3.51 × 10-6 which are comparable to the sole Ag and TiO2 nanoparticles.

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

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

  12. Coating of hydroxyapatite doped Ag on commercially pure titanium surface

    International Nuclear Information System (INIS)

    This paper presents results of bioactive coating on commercially pure titanium surface (CpTi) doped with Ag ions. The coating consists of 3 steps, in step 1- surface chemical treatment of the samples with NaOH, step 2 - immersing the substrate in question in a sodium silicate solution (SS) to the nucleation and step 3 - reimmersion these substrates in synthetic solution that simulates the blood serum for precipitation and growth of apatite layer. After the coating step the AgNO3 substrates were immersed in solutions with concentrations of 20 ppm and 100 ppm at 37 ° C for 48h. The substrates were characterized by scanning electron microscopy (SEM), infrared spectroscopy (IR) and X-ray diffraction (XRD). By the results verified the formation of an apatite layer with aspects of cells, on the surface of CpTi. The increase in Ag concentration causes an increase in Ag amount doped in apatite layer. With the results we concluded that it is possible to obtain an apatite layer on a metal surface as the CpTi doped with Ag ions

  13. Fractal pattern formation in thermal grooving at grain boundaries in Ag films on Si(111) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Roy, A. [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Sundaravel, B. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Batabyal, R. [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Dev, B.N., E-mail: msbnd@iacs.res.in [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)

    2012-05-31

    Growth of Ag films on Br- and H-passivated Si(111) surfaces and the annealing behaviour have been investigated by Rutherford backscattering spectrometry, scanning electron microscopy and photoemission electron microscopy techniques. Upon annealing the phenomenon of thermal grooving was observed in the Ag films. Depending on the annealing temperature, at an intermediate annealing time Ag depletion (evaporation) from the grain boundaries produces fractal patterns of Ag-depleted regions. Continued annealing eventually produces a percolated network of Ag-depleted regions (thermal grooves) along the grain boundaries and isolated Ag grains appear as the depth of the grooves reaches the substrate. For the fractal structures produced by thermal grooving, the fractal dimension has been estimated to be 1.60 {+-} 0.04. Observation of a fractal pattern in thermal grooving was not hitherto reported. A thorough analysis of the experimental results has been carried out in the context of current theories. These theories are inadequate to describe the experimental results. - Highlights: Black-Right-Pointing-Pointer Thermal grooving in Ag films grown on Si(111) surfaces has been investigated. Black-Right-Pointing-Pointer At appropriate temperatures short annealing shows partly depleted grain boundaries. Black-Right-Pointing-Pointer Depleted grain boundaries reveal a fractal pattern with a fractal dimension of 1.60. Black-Right-Pointing-Pointer Long annealing produces percolated Ag-depleted regions with isolated Ag grains. Black-Right-Pointing-Pointer A thorough analysis shows that current theories are unable to explain the results.

  14. Ag/ZnO Nanoparticles as Novel Antibacterial Agent against of Escherichia coli infection, in vitro & in vivo

    Directory of Open Access Journals (Sweden)

    Masoomeh Afzali Poor Khoshkbejari

    2015-09-01

    Full Text Available Urinary tract infection has change a basic challenge in human population. Antibacterial nanoparticles have turned over the new leaf in scientist's research.Ag/ZnO nanoparticleis synthesis in high temperature (5000C.FT-IR, XRD, SEM and TEM were used for determination of spectroscopic, structural and morphology of samples, respectively. Also the nanoparticle was digested and analyzed by ICP-AES for determining the presence of residual chemical element in the nanoparticle. Bacterial sensitivity to nanoparticle was commonly tested using by MIC and MBC tests. For achievement of in vivo tests, the renal of rats were injected and then were infected with E.coli. After that, animals were divided to 9 treatment group and the effect of three concentrations of MIC and MBC; also intermediate concentrations of MIC and MBC and each as a separate group, were studied.The particles size was less of 12nm, approximately. The MIC and MBC observed for Ag/ZnO were 32µgml-1and 512µgml-1 for E.coli, respectively.Treatment with a concentration 512µgml-1ofAg/ZnO nanoparticle in combination with Ciprofloxacin reduced severity of renal cortical thickness of pyelonephrit is rats.The microscopic pathological examination indicated that there was no any severe Inflammation of renal tubules in the groups that had been treated with 512µgml-1concentration of Ag/ZnO nanoparticlein combination with ciprofloxacin. In compared with the control groups.This study showed thatthe Ag/ZnO nanoparticle in cooperation with ciprofloxacin has great antimicrobial effect against E.coli on renal damage of Pyelonephritis.

  15. CTAB-mediated synthesis and characterization of ZnO/Ag core–shell nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Majid; Wei, Chengsha; Chen, Mingming; Tao, Jiaojiao; Huang, Ningdong; Qi, Zeming, E-mail: zmqi@ustc.edu.cn; Li, Liangbin

    2014-11-05

    Graphical abstract: Simplified schematic process for ZnO NRs/Ag nanocomposites. - Highlights: • A new simple and facile approach to synthesize ZnO NRs/Ag core–shell nanocomposite. • The annealing improves the crystallinity and bond strength between Ag and ZnO. • CTAB and AgNO3 greatly affect the formation of ZnO NRs/Ag core–shell. • Strong interfacial interaction between Ag nanoparticles and ZnO nanorods. - Abstract: In this paper, ZnO/Ag core–shell hybrid nanocomposites have been prepared by a very simple chemical methodology. ZnO nanorods were employed as core material for Ag seeds, and subsequent nucleation and growth of Ag nanoparticle by a cationic surfactant cetyltrimethylammonium bromide (CTAB) formed the ZnO NRs/Ag core–shell nanocomposites. In addition, their morphology, microstructure and optical properties have been characterized by X-ray diffraction, Raman Spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, UV–Vis absorption and photoluminescence spectroscopy. It was found that face-center-cubic Ag nanoparticles with an average diameter of 20 nm were coated onto the surface of hexagonal phase ZnO nanorods with a minimum of 0.09 mmol concentration of CTAB. The excitonic absorption band and surface plasmon absorption band of the ZnO NRs/Ag nanocomposites revealed red-shifts relative to pure ZnO nanorods and metallic Ag nanoparticles. The coating of Ag nanoparticles onto the ZnO nanorods show red-shift in the near band edge (NBE) luminescence spectra and a reasonable detraction in the deep level emission (DLE) spectra compared with the pure ZnO nanorods. These interpretations demonstrated the strong interfacial interaction between Ag nanoparticles and ZnO nanorods. Furthermore, the annealing of ZnO NRs/Ag nanocomposite at 200 °C was done and improvement occurs in the crystallinity and binding strength of Ag nanoparticles.

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

    Science.gov (United States)

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

    2012-10-01

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

  17. Comparison of serum HBsAg quantitation by four immunoassays, and relationships of HBsAg level with HBV replication and HBV genotypes.

    Directory of Open Access Journals (Sweden)

    Edouard Tuaillon

    Full Text Available BACKGROUND: The decline in hepatitis B virus surface antigen (HBsAg may be an early predictor of the viral efficacy of Hepatitis B virus (HBV therapy. The HBsAg levels obtained by different immunoassays now need comparing and the relationships between levels of HBsAg and HBV DNA alongside HBsAg and genotype must be evaluated. METHODOLOGY/PRINCIPAL FINDINGS: HBsAg levels were compared among 80 patients using the Abbott Architect assay, a commercial immunoassay approved for HBsAg detection and quantitation, and three other assays derived from immunoassays approved for HBsAg detection (manufactured by Diasorin, Bio-Rad and Roche. Good correlation was found between the Abbot vs. Diasorin, Bio-Rad and Roche assays with narrow 95% limits of agreement and small mean differences: -0.06 to 0.11, -0.09 log(10 IU/mL; -0.57 to 0.64, -0.04 log(10 IU/mL; -0.09 to 0.45, -0.27 log(10 IU/mL, respectively. These agreements were not affected by genotypes A or D. HBsAg was weakly correlated with HBV DNA, whatever the HBsAg assay used: Abbott, ρ = 0.36 p = 0.001, Diasorin ρ = 0.34, p = 0.002; Bio-Rad ρ = 0.37, p<0.001; or Roche ρ = 0.41, p<0.001. This relationship between levels of HBsAg and HBV DNA seemed to depend on genotypes. Whereas HBsAg (Abbott assay tended to correlate with HBV DNA for genotype A (ρ = 0.44, p = 0.02, no such correlation was significant for genotypes D (ρ = 0.29, p = 0.15. CONCLUSION/SIGNIFICANCE: The quantitation of HBsAg in routine clinical samples is comparable between the reference assay and the adapted assays with acceptable accuracy limits, low levels of variability and minimum discrepancy. While HBsAg quantitation is not affected by HBV genotype, the observed association between levels of HBsAg and HBV DNA seems genotype dependent.

  18. The preparation and visible- light photocatalysis of Ag3PO4/TiOxNy%Ag3PO4/TiOxNy的制备及可见光催化性能

    Institute of Scientific and Technical Information of China (English)

    郑华荣; 刘长安; 苏文悦; 王绪绪

    2011-01-01

    采用溶胶-凝胶法制备Ag3 PO4/TiOxNy催化剂,运用低温N2吸附、X射线粉末衍射、紫外可见漫反射、程序升温脱附-质谱联用和电子自旋共振谱等测试手段对催化剂的理化性质和活性物种等进行详细表征,并以苯的可见光催化降解为反应模型考察样品的光催化活性.结果表明,Ag3PO4修饰改善了TiOxNy的结构和可见光催化活性,与TiOxNy相比,Ag3PO4/TiOxNy催化剂的的BET比表面积大、光谱吸收边红移、锐钛矿向金红石的相转化被抑制,对苯的吸附显著增强,光生电子和空穴得到有效分离,具有良好的可见光催化活性.%Ag3PO4/TiOxNγ photocatalysts are prepared by a sol -gel method. The physical properties and active species of the as - prepared samples are characterized by N2 sorption analysis, X - ray dif fraction (XRD) , UV - Vis diffuse reflectance spectroscopy ( UV - Vis DRS), TPD - MS and ESR. Visible -light photocatalytic decomposition of gaseous benzene over the Ag3PO4/TiOxNr catalysts was investigated. The results showed that the catalytic and structural properties of TiO,,Nr were improved by Ag3PO4 modifying. When compared to unmodified TiO,,Nr, the Ag3PO4/TiO,Nr exhibited higher re sistance to crystal phase transformation from anatase to rutile, bigger BET specific area, the red - shif ted band edge of adsorption spectra, and higher photocatalytic activities because of the adsorption en richment of benzene and of the effective photogenerated electron - hole pair' s separation.

  19. Probable metal-insulator transition in Ag4SSe

    International Nuclear Information System (INIS)

    Highlights: • New phase transition in Ag4SSe was discovered with scanning calorimetry and supported with X-ray powder diffraction. • The thermal effect relates to the anomaly in electrical and thermal conductivity of Ag4SSe. • Similar thermal and electrical effects in K3Cu8S6 are explained with the metal-insulator transition. - Abstract: New phase transition (285 K) in low-temperature monoclinic Ag4SSe was found out below the α-β transition (358 K) after the measurements with differential scanning calorimetry. The transition reveals significant hysteresis (over 30 K). X-ray powder diffraction shows that the superlattice with doubled a and b parameters of the unit cell exists below the new transition point. The signs of this new phase transition can be found in thermal and electrical conductivity of Ag4SSe published in literature. Elusive phase transition in Ag2Se shows similar properties. The new transition is likely related to the metal-insulator type transition, like K3Cu8S6

  20. 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

  1. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

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

  2. About AgEcon Search

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

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

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

    International Nuclear Information System (INIS)

    Ag/Ag2S heterojunction nanowires (HJNWs) have been successfully fabricated through one-pot solution-phase method, which were transferred into Ag/CdS HJNWs by cation exchange. The synthesis involved a template-less, non-seed, and one-pot solution-phase process to high-quality Ag/Ag2S HJNWs. The sizes, positions, and spacing distances between the Ag2S or CdS NPs of the growing Ag2S and CdS NPs in the Ag/Ag2S and Ag/CdS HJNWs could be finely tailored by reaction temperatures and PVP concentrations. By varying reaction temperature, the sizes and positions (tip or surface) of the growing Ag2S and CdS NPs in the Ag/Ag2S and Ag/CdS HJNWs could be effectively controlled while PVP concentration could tailor the sizes and spacing distances between the Ag2S or CdS NPs of the growing Ag2S and CdS NPs in the Ag/Ag2S and Ag/CdS HJNWs. We also proposed a primary experimental model to illustrate the growth mechanism of the Ag/Ag2S and Ag/CdS HJNWs

  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. The Effect of (Ag, Ni, Zn-Addition on the Thermoelectric Properties of Copper Aluminate

    Directory of Open Access Journals (Sweden)

    Jianxiao Xu

    2010-01-01

    Full Text Available Polycrystalline bulk copper aluminate Cu1-x-yAgxByAlO2 with B = Ni or Zn were prepared by spark plasma sintering and subsequent thermal treatment. The influence of partial substitution of Ag, Ni and Zn for Cu-sites in CuAlO2 on the high temperature thermoelectric properties has been studied. The addition of Ag and Zn was found to enhance the formation of CuAlO2 phase and to increase the electrical conductivity. The addition of Ag or Ag and Ni on the other hand decreases the electrical conductivity. The highest power factor of 1.26 × 10-4 W/mK2 was obtained for the addition of Ag and Zn at 1,060 K, indicating a significant improvement compared with the non-doped CuAlO2 sample.

  6. Enhanced Thermoelectric Performance of Bi2O2Se with Ag Addition

    Directory of Open Access Journals (Sweden)

    Bin Zhan

    2015-04-01

    Full Text Available Polycrystalline Bi2O2Se/Ag nanocomposites were synthesized by spark plasma sintering process. Their thermoelectric properties were evaluated from 300 to 673 K. With the addition of silver, the conductive second phase Ag2Se and Ag can be observed, which results in a significant enhancement of electrical conductivity. The maximum conductivity is 691.8 S cm−1 for Bi2O2Se/20 vol.% Ag, which increased nearly 500 higher times than the pure Bi2O2Se bulk. ZT value can be enhanced greatly, ~0.07, for Bi2O2Se/5 vol.% Ag at 673 K, which is two times larger than the pure sample.

  7. Bio-inspired sustainable and green synthesis of plasmonic Ag/AgCl nanoparticles for enhanced degradation of organic compound from aqueous phase.

    Science.gov (United States)

    Devi, Th Babita; Ahmaruzzaman, M

    2016-09-01

    In the current study, we report the utilization of the biogenic potential of Benincasa hispida (ash gourd) peel extract for the synthesis of Ag embedded AgCl nanoparticles nanoparticles (Ag/AgCl NPs) without the use of any external organic solvents. The appearance of dark brown color from the pale yellow color confirmed the formation of Ag/AgCl nanoparticles which was further validated by absorbance peak using UV-visible spectroscopy. The phytochemicals (flavones) present in the B. hispida peel extract acts as a reducing/stabilizing agents. The morphology and size of the synthesized NPs were characterized by transmission electron microscope (TEM), selected area electron microscope (SAED) and high resolution transmission electron microscope (HR-TEM). FT-IR spectra of the B. hispida peel extract and after the development of nanoparticles are determined to identify the functional groups responsible for the conversion of metal ions to metal nanoparticles. The synthesized nanoparticles showed an excellent photocatalytic property in the degradation of toxic dye like malachite green oxalate under sunlight irradiation. For the first time, malachite green oxalate dye was degraded by Ag/AgCl nanoparticles under sunlight irradiation. PMID:27246560

  8. Bio-inspired sustainable and green synthesis of plasmonic Ag/AgCl nanoparticles for enhanced degradation of organic compound from aqueous phase.

    Science.gov (United States)

    Devi, Th Babita; Ahmaruzzaman, M

    2016-09-01

    In the current study, we report the utilization of the biogenic potential of Benincasa hispida (ash gourd) peel extract for the synthesis of Ag embedded AgCl nanoparticles nanoparticles (Ag/AgCl NPs) without the use of any external organic solvents. The appearance of dark brown color from the pale yellow color confirmed the formation of Ag/AgCl nanoparticles which was further validated by absorbance peak using UV-visible spectroscopy. The phytochemicals (flavones) present in the B. hispida peel extract acts as a reducing/stabilizing agents. The morphology and size of the synthesized NPs were characterized by transmission electron microscope (TEM), selected area electron microscope (SAED) and high resolution transmission electron microscope (HR-TEM). FT-IR spectra of the B. hispida peel extract and after the development of nanoparticles are determined to identify the functional groups responsible for the conversion of metal ions to metal nanoparticles. The synthesized nanoparticles showed an excellent photocatalytic property in the degradation of toxic dye like malachite green oxalate under sunlight irradiation. For the first time, malachite green oxalate dye was degraded by Ag/AgCl nanoparticles under sunlight irradiation.

  9. Contact geometry and electronic transport properties of Ag–benzene–Ag molecular junctions

    International Nuclear Information System (INIS)

    Highlights: ► We simulate Ag–benzene–Ag junctions with different contact geometries. ► Moderate benzene–Ag interactions can be realized for adsorptions through Ag adatoms. ► Molecular orbitals dominating the low-bias conductance match the contact symmetry. ► Three contact geometries deliver similar conductance consistent with the experiments. - Abstract: Contact geometry and the electronic transport properties of Ag–benzene–Ag molecular junctions have been investigated by using first-principles quantum transport simulations. Our calculations show that a moderate benzene–silver interaction can be achieved when benzene is adsorbed on the Ag(1 1 1) surface through adatoms. In this case three symmetric Ag–benzene–Ag junction models can be constructed, in which the molecule is connected to the electrodes through one or two Ag adatoms on each side. Although the contribution to the transmission around the Fermi level made by the benzene molecular orbitals depends on the number of Ag adatoms and the detailed binding configuration, the transmission coefficients at the Fermi level of the three junctions are calculated to be respectively 0.20, 0.18 and 0.16. These values are well consistent with the experimental ones of 0.24 ± 0.08. Our results thus demonstrate that the conductance of Ag–benzene–Ag junctions is rather stable regardless of the molecule/electrode contact geometry.

  10. Spatial and temporal variation of surface-enhanced Raman scattering at Ag nanowires in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Clayton, Daniel A.; McPherson, Tyler; Pan, Shanlin; Chen, Mingyang; Dixon, David A.; Hu, Dehong

    2012-12-13

    We present surface enhanced Raman spectroscopy (SERS) and Raman imaging of small organic molecules at well-defined nanostructures formed by single silver nanowires (NWs). We show that SERS can be obtained at single, crossed, and bundled Ag NWs for mercaptopyridine, adenine, cytosine, guanine, and thymine. Crossed wires and parallel Ag NWs have SERS enhancement factors much higher than single Ag NWs. New additional junctions formed by a silver nanoparticle and a single Ag NW, and bundled NWs provide SERS intensity higher than a single Ag NW. The SERS signal of single Ag NWs can be further enhanced by decorating the Ag NW surface with gold nanoparticles using electroless deposition. Single Ag NW Raman imaging with a 10 ms time resolution when compared with photoluminescence (PL) imaging results reveal a different dynamic response of SERS and PL under steady state laser excitation. Dynamic photoluminescence blinking activities are suppressed in the presence of the surface coating of Raman active molecules (e.g., mercaptopyridine) and the SERS signal is quite stable in a wide field excitation configuration. The Discrete Dipole Approximation (DDA) method was used to calculate the local field intensity that can be applied to help understand the enhanced PL and SERS at the junction of Ag NWs

  11. Preparation and properties of nano-sized Ag and Ag2S particles in biopolymer matrix

    Science.gov (United States)

    Božanić, D. K.; Djoković, V.; Blanuša, J.; Nair, P. S.; Georges, M. K.; Radhakrishnan, T.

    2007-01-01

    Silver (Ag) and silver sulfide (Ag2S) nanoparticles were synthesized in a sago starch matrix. The resulting nanocomposites were investigated using structural, optical and thermal methods. XRD spectra of the nanocomposites confirmed the presence of nanostructured silver (cubic phase) and silver sulfide (monoclinic phase) in the matrix. TEM micrographs showed that the nanoparticles are mostly spherical in shape. Analyzes of the optical properties of the silver nanocomposite aqueous dispersions/solutions of various concentrations were carried out. The results and the theoretical considerations suggested that at high concentrations there is a release of silver nanoparticles from the composite in the water environment. Further dilution produces homogeneous solution in which silver nanoparticles are capped with starch macromolecules. TGA analysis revealed reduced thermal stability of the nanocomposites with respect to pure starch matrix.

  12. Current-perpendicular-to-the-plane giant magnetoresistance in spin-valves with AgSn alloy spacers

    Energy Technology Data Exchange (ETDEWEB)

    Read, J. C.; Nakatani, T. M.; Smith, Neil; Choi, Y.-S.; York, B. R.; Brinkman, E.; Childress, J. R. [San Jose Research Center, HGST, a Western Digital Company, San Jose, California 95135 (United States)

    2015-07-28

    We investigate the use of AgSn alloys as the spacer layer in current-perpendicular-to-the-plane magnetoresistance devices. Alloying with Sn increases resistivity but results in a reasonably long (>10 nm) spin-diffusion length, so large magnetoresistance can be achieved with thin AgSn spacers. Compared to Ag thin films, AgSn forms smaller grain sizes, reduced roughness, and exhibits less interdiffusion upon annealing, resulting in decreased interlayer magnetic coupling in exchange biased spin-valves. AgSn also shows improved corrosion resistance compared to Ag, which is advantageous for nanofabrication, including magnetic recording head sensors. Combining a AgSn spacer with Co-based Heusler alloy ferromagnet in an exchange biased, polycrystalline trilayer thinner than 12 nm results in magnetoresistance values up to 15% at room temperature.

  13. Current-perpendicular-to-the-plane giant magnetoresistance in spin-valves with AgSn alloy spacers

    Science.gov (United States)

    Read, J. C.; Nakatani, T. M.; Smith, Neil; Choi, Y.-S.; York, B. R.; Brinkman, E.; Childress, J. R.

    2015-07-01

    We investigate the use of AgSn alloys as the spacer layer in current-perpendicular-to-the-plane magnetoresistance devices. Alloying with Sn increases resistivity but results in a reasonably long (>10 nm) spin-diffusion length, so large magnetoresistance can be achieved with thin AgSn spacers. Compared to Ag thin films, AgSn forms smaller grain sizes, reduced roughness, and exhibits less interdiffusion upon annealing, resulting in decreased interlayer magnetic coupling in exchange biased spin-valves. AgSn also shows improved corrosion resistance compared to Ag, which is advantageous for nanofabrication, including magnetic recording head sensors. Combining a AgSn spacer with Co-based Heusler alloy ferromagnet in an exchange biased, polycrystalline trilayer thinner than 12 nm results in magnetoresistance values up to 15% at room temperature.

  14. D.C. conductivity and spectroscopic studies of polyaniline doped with binary dopant ZrOCl2/AgI

    Indian Academy of Sciences (India)

    Kiran Kumari; Vazid Ali; Anand Kumar; Sushil Kumar; M Zulfequar

    2011-10-01

    Aqueous binary dopant (ZrOCl2/AgI) is used in different ratios such as 1:1, 1:2 and 2:1 (w/w) for chemical doping to enhance the conductivity of synthesized polyaniline (PANI). The doping of polyaniline is carried out using tetrahydrofuran as a solvent. Doped samples are characterized using various techniques such as – characteristics, UV-visible spectroscopy, X-ray diffractometry (XRD), FTIR and photoluminescence (PL) studies. A significant enhancement in d.c. conductivity has been observed with the introduction of binary dopant. UV-visible study shows that optical parameters change considerably after doping. Interestingly, both direct and indirect bandgaps are observed in the doped samples. XRD patterns show the semi-crystalline nature of doped polyaniline. FTIR study shows structural modifications in functional groups with doping in PANI. Photoluminescence spectra exhibit emission properties of the samples.

  15. Accumulation of Ag and Cu in Amanita strobiliformis and characterization of its Cu and Ag uptake transporter genes AsCTR2 and AsCTR3.

    Science.gov (United States)

    Beneš, Vojtěch; Hložková, Kateřina; Matěnová, Michaela; Borovička, Jan; Kotrba, Pavel

    2016-04-01

    Macrofungi can accumulate in their sporocarps remarkably high concentrations of Cu and Ag. We have previously demonstrated that the non-essential Ag is in the ectomycorrhizal, Ag-hyperaccumulating Amanita strobiliformis sequestered by 3.4-kDa metallothioneins (MTs) produced as AsMT1a, 1b and 1c isoforms. Here, we describe two populations of wild-grown A. strobiliformis sporocarps, which showed certain correlation between the concentrations of accumulated Ag (284 ± 64 and 67 ± 15 mg kg(-1)) and Cu (76 ± 13 and 30 ± 12 mg kg(-1)), suggesting that an overlap may exist in the cell biology of Ag and Cu in this species. Metal speciation analysis revealed that the intracellular Cu in the sporocarps of both populations was, like Ag, associated with the 3.4-kDa MTs. A search of A. strobiliformis transcriptome for sequences encoding proteins of the Cu transporter (CTR) family identified four AsCTR cDNAs, which were, like AsMT1s, confirmed in both populations. The predicted AsCTR proteins showed homology to vacuolar (AsCTR1 and AsCTR4) and plasma membrane (AsCTR2 and AsCTR3) CTRs. Heterologous expression of AsCTR2, AsCTR3 and their translational fusions with green fluorescent protein (GFP) in Cu uptake-deficient S. cerevisiae indicated that both AsCTRs are functional Cu and Ag uptake transporters: recombinant genes complemented growth defects and increased Cu and Ag uptake rates in yeasts and the GFP-tagged protein localized to the cell periphery. Site directed mutagenesis revealed the importance of the conserved-among-CTRs M-X3-M motif for the AsCTR2- and AsCTR3-mediated transport of both Cu and Ag. These results provide the first evidence that fungal CTRs can recognize Ag for transport. PMID:26862109

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

    Science.gov (United States)

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

    2015-06-01

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

  17. 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.

  18. 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.

  19. 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.

  20. Quaternized chitosan/rectorite/AgNP nanocomposite catalyst for reduction of 4-nitrophenol

    Energy Technology Data Exchange (ETDEWEB)

    Ling, Yunzhi [State Key Laboratory of Pulp & Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Zeng, Xianjie [School of Business Administration, South China University of Technology, Guangzhou 510640 (China); Tan, Weirui [State Key Laboratory of Pulp & Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Luo, Jiwen, E-mail: holdit@126.com [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); State Key Laboratory of Pulp & Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Liu, Shijie, E-mail: sjliu@163.com [State Key Laboratory of Pulp & Paper Engineering, South China University of Technology, Guangzhou 510640 (China); China Department of Paper and Bioprocess Engineering, State University of New York, College of Environmental Science and Forestry, 1 Forestry Drive, Syracuse, NY 13210 (United States)

    2015-10-25

    This study investigated a one-step green fabrication of exfoliated quaternized chitosan/rectorite/AgNP nanocomposites under microwave radiation method. The nanocomposites were characterized by FT-IR, XRD, XPS and TEM. The results revealed that quaternized chitosan and rectorite acted as reducing and stabilizing agents, spherical AgNPs were synthesized greenly and rapidly, meanwhile the layers of rectorite were exfoliated, and when the ratio of quaternized chitosan, rectorite and silver nitrate was 100 mg: 10 mg: 2 mmol, the AgNP content reached the maximum of 2.73%. Then, the quaternized chitosan/rectorite/AgNP nanocomposite was fabricated as a film, which was used in the catalytic reduction from 4-nitrophenol to 4-aminophenol by NaBH{sub 4}. The film showed excellent catalytic efficiency with an activation energy of 29.76 kJ mol{sup −1} and outstanding reusable performance even after catalysis for 10 times. - Graphical abstract: Quaternized chitosan/rectorite/AgNP nanocomposite catalyst was prepared greenly in one pot and fabricated as a film, which showed excellent catalytic efficiency and reusable performance. - Highlights: • Quaternized chitosan and rectorite acted as reducing and stabilizing agents. • Spherical Ag NPs were synthesized greenly and rapidly. • AgNP dispersed well on the surface and the interlayer of exfoliated rectorite. • Quaternized chitosan/rectorite/AgNP nanocomposite was prepared as a film. • The film showed excellent catalytic efficiency and reusable performance.