• 한국재료학회지
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• 제8권5호
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• pp.394-398
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• 1998

은(Ag)의 첨가가$ YBa_{2}$$Cu_{3}$$O_{7-\delta}$ (YBCO) 고온초전도체의 미세조직, 기계적 및 전기적 성질에 미치는 효과를 연구하였다. 소량의 Af(5, 10, 15 vol.%)는 각각 금속분말상태와 질산염인 $AgNO_{3}$초전도체의 강도와 인성값이 Ag의 함량이 증가할수록 높게 나타났으며, 이는 Ag입자에 의해 야기되는 강화기루에 의한 것으로 생각된다. 또한 Ag를 질산염의 분말상태로 첨가하여 만든 YBCO-Ag 복합재료가 금속분말상태로 첨가하여 만들었을 때보다 강도 및 인성값이 더 우수한 것으로 나타났다. $AgNO_{3}$를 첨가한 복합체가 상대적으로 더 우수한 기계적 성질을 가지는 것은 Ag 입자가 더 미세하고 균일하게 분포되었기 때문으로 판단된다. Ag 첨가로 인해 YBCO 복합초전도체의 전류밀도값은 미세하게 증가하는 것으로 관찰되었다.

• Elastomers and Composites
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• 제57권1호
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• pp.1-8
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• 2022

In this study, the photo-deposition method was used to introduce Ag onto the surface of TiO₂ to synthesize an Ag-TiO₂ composite. The effects of the varying amounts of AgNO₃ precursor and annealing time periods on the Ag content in the composites, as well as their antibacterial characteristics under visible light conditions were studied. SEM analysis revealed the spherical morphology of the Ag-TiO₂ composite. Compared with TiO₂, the Ag particles were too small to be observed. An XPS analysis of the Ag-TiO₂ surface confirmed the Ag content and showed the peak intensities for elements such as Ag, Ti, O, C, and Si. The highest Ag content was observed when 33.3 wt.% of AgNO₃ and an annealing time of 6 h were employed; this was the optimum annealing time for Ti-Ag-O bonding, in that the lowest number of O bonds and the highest number of Ag bonds were confirmed by XPS analysis. Superior antibacterial properties against Bacillus and Escherichia coli, in addition to the widest inhibition zones were exhibited by the Ag-TiO₂ composite with an increased Ag content in a disk diffusion test, the bacterial reduction rate against Staphylococcus aureus and Escherichia coli being 99.9%.

• 한국전기전자재료학회논문지
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• 제20권6호
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• pp.561-565
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• 2007

Because of a good wear resistance and a stable contact resistance, Ag-CdO is widely used as electrical contact material. But, the Cd-oxide mainly exists as a coarse particle and adversely affected to environment. As a reason, $Ag-SnO_2$ alloy has been developed. The Sn-oxide maintains stable and fine particle even at high temperature. In order to investigate the effect of Misch metal (Mm) additional that affects the formation of the oxide and the formation of fine matrix Ag, we studied the microstructures and properties of Ag-Sn-In(-Mm) material fabricated by rapid solidification process. The experimental procedure were melting using high frequency induction, melt spinning, and internal oxidation. The Mm addition makes Ag matrix more fine than no Mm addition. The reason is that the addition of Misch metal decreased a latent heat of fusion of alloy, as a result the rapid solidification effect of alloy is increased. The maximum hardness shows at 0.3 wt%Mm. after that the hardness is decreased until 0.4 wt% Mm, but still larger than no Mm addition alloy. At 0.5 wt% Mm alloy, the precipitation of Misch metal causes a decrease of hardness than no Mm addition alloy.

• 멤브레인
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• 제27권4호
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• pp.313-318
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• 2017

올레핀/파라핀 분리를 위해 $Poly(ethylene oxide)(PEO)/AgBF_4/Al(NO_3)_3/Ag_2O$ 복합막이 제조되었으며, $Ag_2O$가 도입되었을 때, 복합체 분리막의 초기성능은 선택도 13.7과 투과도 21.7 GPU로 관찰되었다. $PEO/AgBF_4/Al(NO_3)_3$ 분리막의 성능(선택도 13와 투과도 7.5 GPU)에 비해서 초기성능이 증가한 이유는 $Ag_2O$의 첨가로 인한 Ag ion의 활성도 증가로 생각되었다. 하지만 시간에 따른 성능저하 현상이 관찰되었는데 이는 고분자 matrix인 PEO 때문인 것으로 생각되었다. PEO 고분자는 $Ag_2O$ 입자를 안정화 시킬 수 없기 때문에 용매가 증발하면서 $Ag_2O$ 입자끼리 뭉치게 되고, $Ag_2O$가 barrier 역할을 하게 돼서 시간이 지나면 투과도가 감소하는 것으로 분석되었다.

• 멤브레인
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• 제28권4호
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• pp.260-264
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• 2018

올레핀/파라핀 분리를 위해 poly(ethylene oxide)(PEO)/Ag nanoparticles (AgNPs)(전구체: $AgBF_4$)/p-benzoquinone (p-BQ) 복합막이 제조되었으며, 이 복합체 분리막의 성능은 100시간까지 선택도 10과 투과도 15 GPU로 유지되는 것이 관찰되었다. 분리막의 성능이 100시간까지 유지할 수 있었던 이유는 p-BQ의 첨가로 인해 Ag ion이 안정적으로 Ag nanoparticles로 형성될 수 있었을 뿐더러 전자수용체인 p-BQ으로 인해 표면이 부분 양극성화 되어 올레핀 운반체로서 역할을 성공적으로 수행한 결과라 생각되었다. 본 연구에서는 Ag nanoparticles의 전구체로 사용된 $AgBF_4$의 가격이 고가이기 때문에 가격 측면에서 유리한 $AgNO_3$ Ag nanoparticles의 전구체로 사용하여 실험을 진행하였다. 그 결과로서 $AgNO_3$의 경우에는 앞선 $AgBF_4$과는 다르게 안정적으로 은 나노입자가 형성되지 못하고 이로 인하여 좋은 성능을 내지 못하는 것으로 분석되었다.

• 한국분말재료학회지
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• 제5권2호
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• pp.139-144
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• 1998

We have evaluated the role of Ag additions on the strength, fracture toughness, elastic modulus and resistance to thermal shock of $YBa_2Cu_3O_{7-x}$(YBCO) superconductor. Addition of 10 vol.% Ag improved strength and fracture toughness, whereas, decreased elastic modulus of YBCO. In addition, YBCO-Ag composites improved resistance to thermal shock probably due to enhanced strength, fracture toughness and thermal conductivity as a result of Ag addition. It is to be noted that YBCO-Ag made by mixing with $AgNO_3$ solution showed slightly higher strength, fracture toughness and resistance to thermal shock, compared to that made by mixing with metallic Ag powder. These improvements are believed to be due to the microstructure of more finely and uniformly distributed Ag particles.

• 한국표면공학회지
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• 제42권1호
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• pp.47-52
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• 2009

Cu-Ag powder having Core-Shell structure was prepared from by electroless plating method using agents such as $AgNO_3$, $NH_{4}OH$, Hydroquinone. Ag coated copper powders were analyzed using scanning electron microscopy(SEM) and energy dispersive X-ray spectrometer(EDX). The silver coating layer of copper powder was affected from various reaction conditions such as molar ratio of $NH_{4}OH$, $AgNO_3$, and pulp density. Free silver was generated below 0.1M or 0.3M and above of $NH_{4}OH$ mole ratio. Silver coating layer thickened as addition of $AgNO_3$. When the pulp density reached 12% with 0.2M $NH_{4}OH$, and 0.15M $AgNO_3$ at $4^{\circ}C$, silver was homogeneously distributed around the copper particles and free silver particles were not generated.

• 공업화학
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• 제16권3호
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• pp.328-336
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• 2005

본 연구에서는 배출가스 중에 포함된 NO를 비선택적 촉매환원법으로 환원시켜 제거하기 위하여 Ag와 V의 함량을 여러 가지로 달리하여 ${\gamma}-Al_2O_3$에 담지한 촉매를 제조하였고, 제조한 촉매에 대하여 온도, 산소농도, 아황산가스농도의 변화에 따른 $NO_x$의 전환율에 대하여 연구하였다. 또한 제조한 촉매의 물성분석을 통하여 촉매의 상태와 $NO_x$의 전환율과의 관계를 알아보았다. $AgV/{\gamma}-Al_2O_3$ 촉매의 경우에는 고온에서는 $Ag/{\gamma}-Al_2O_3$ 촉매보다 낮은 $NO_x$ 전환율을 나타내는 반면에 저온에서는$Ag/{\gamma}-Al_2O_3$ 촉매보다 높은 $NO_x$ 전환율을 나타내었고, 반응가스 중에 $SO_2$가 함유되어 있어도 $NO_x$의 전환율이 낮아지지 않았다. 반응실험 전 후의 촉매에 대하여 X-ray Diffraction, X-ray Photo electron Spectroscopy, Temperature Programmed Reduction, Ultraviolet-Visible Diffuse Reflectance Spectroscopy 등의 분석결과와 반응실험 결과를 비교하여 볼 때 V가 포함됨으로 인하여 Ag의 산화상태가 잘 유지되지 못하여 고온에서는 $NO_x$ 전환율이 낮아지며, $300^{\circ}C$ 이하의 저온에서는 V의 촉매작용으로 인하여 $NO_x$ 전환율이 높아진 것으로 나타났다.

• 한국분말재료학회지
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• 제11권6호
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• pp.477-485
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• 2004

Monodispersed flaky silver powder was obtained by controlling the ratios of $H_{2}O_{2}/NH_{3}$ and Agin in a mixed solution of ethylene glycol and ammonia with an addition of PVP. The effects of $NH_{3}/Ag,\; H_{2}O_{2}/Ag\;and\;H_{2}PtCl_{6}/Ag$ on its morphology and size were investigated. In $H_{2}O_{2}-NH_{3}-AgNO_{3}\;system,\;NH_{3}/Ag$ molar ratio was found to be an important reaction factor for the nucleation and crystal growth of Ag powder. The synthesis of flaky powder was optimized at over 6 of $NH_{3}/Ag \;and\;5\;of\;H_{2}O_{2}/Ag\;under\;1.0{\times}10^{-3}\;of\;Pt/Ag.\;Moreover,\;as\;the\; NH_{3}/Ag$ molar ratio increased, the size of precipitates was increased regardless of the amount of Pt. In the absence of $H_{2}PtCI$, the morphology and size of reduced Ag powder were found to be irregular in shape $2-4{\mu}m$ in diameter. However, homogenized fine Ag powder was obtained due to heterogeneous nucleation when $H_{2}PtCI$ used as a cat-alyst, and flaky one was synthesized with the addition of Pt over $1.0{\times}10^{-3}$ of Pt/Ag.

• 생명과학회지
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• 제10권6호
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• pp.558-563
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• 2000

Effect of inhibitors on Vibrio parahaemolyticus cell growth and its urease activity was studied. The growth of the bacterium and the enzyme activity were inhibited by the addition of 0.02% p-hydroxymercuric benzoate, $HgCl_2$and $AgNO_3$. However, same concentration of boric acid, thallium acetate and $Pb(NO_3)_2$ did not affect the cell growth but inhibited urease activity by 25%, 29%, and 38%, respectively. Acetohydroxamic acid was the most potent inhibitor on cell growth by inhibiting 40% but did not affect urease activity. To investigate the effect of inhibitors on urease activity, urease was purified and confirmed on SDS-PAGE. The purified urease was inhibited 100% by the addition of 1 mM acetohydroxamic acid and $AgNO_3$but no inhibition was occurred by the addition of the same concentration of thallium acetate. and the addition of 0.01 mM of $HgCl_2$ and acetohydroxamic acid inhibited the purified urease activity by 39% and 24%, respectively. On 0.1 millimolar basic, acetohydroxamic acid and $HgCl_2$inhibited 4 times more active in urease inhibition than p-hydroxymercuric benzoate whereas no inhibition was occurred either thallium acetate or $Pb(NO_3)_2$.