• 제목/요약/키워드: silver

검색결과 3,468건 처리시간 0.061초

A Facile Preparation of Silver Nanocolloids by Hydrogen Reduction of a Silver Alkylcarbamate Complex

  • Hong, Hyun-Ki;Gong, Myoung-Seon;Park, Chan-Kyo
    • Bulletin of the Korean Chemical Society
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    • 제30권11호
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    • pp.2669-2674
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    • 2009
  • Controlled reduction of silver alkylcarbamate complexes with hydrogen gas was investigated as a facile synthetic method for high concentrations of silver nanocolloids in organic solvent. Polyvinylpyrrolidone (PVP) was used to stabilize the silver colloids obtained from the chemical reduction. To determine optimum conditions for preparation of the stable and controlled silver colloids with the narrowest particle size and distribution, a large number of experiments were carried out involving variations in the concentrations of the silver 2-ethylhexylcarbamate (Ag-EHCB) complex, PVP, and 2-propanol. The initial colloid had a mean particle diameter between 5$\sim$50 nm, as measured by transmission electron microscopy, and exhibited a sharp absorption band in the UV region with a maximum size near 420 nm. After treatment with a reducing agent, the colloids were characterized by ultraviolet-visible spectroscopy, X-ray diffraction, and high-resolution transmission electron microscopy.

Silver-polyner 적합도전류물에서 은립자의 분석상태가 전기운도에 미치는 영향 (Effect of Dispersion of Silver Particles on the Electrical Conduction in Silver-Polymer Composites.)

  • 김한성;김재호
    • 대한전기학회논문지
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    • 제37권1호
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    • pp.55-62
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    • 1988
  • The variation of electrical resistivity of silver particle-filled polymers with the volume percent of silver particles was investigated. Also, the relationships between the surface tension of polymer and dispersion effect of silver particles were studied to find the steep drop of electrical resisivity, in view of agglomerate morphology. The critical volume precent of silver particles varied depending on the polymer species and increased with the increasing surface tension of polymer. The steep variation of resistivity with the increasing temperature was explained with the expansion of polymer at the melting temperature of polymer. The conductive break down current increased with the increasing volume percent of silver particles in the Ag/LDPE system and that was attributed to heat of Joule taken througn the contact area between the silver particle.

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Adsorption and Desorption Characteristics of Methyl iodide on Silver ion-Exchanged Synthetic Zeolite at High Temperature

  • Park, Geun-Il;Park, Byung-Sun;Cho, Il-Hoon;Kim, Joon-Hyung;Ryu, Seung-Kon
    • Nuclear Engineering and Technology
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    • 제32권5호
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    • pp.504-513
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    • 2000
  • The adsorption characteristics of methyl iodide generated from the simulated off-gas stream on various adsorbents such as silver ion-exchanged zeolite (AgX), zeocarbon and activated carbon were investigated. An extensive evaluation was made on the optimal silver ion-exchanged level for the effective removal of methyl iodide at temperature up to 38$0^{\circ}C$. The degree of adsorption efficiency of methyl iodide on silver ion-exchanged zeolite is strongly dependent of silver ion-amount and process temperature. The influence of temperature, methyl iodide concentration and silver ion-exchanged level on the adsorption efficiency is closely related to the pore characteristics of adsorbents. It would be facts that the effective silver ion-exchanged level was about 10 wt%, based on the degree of silver utilization for the removal of methyl iodide.

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은 박막이 코팅된 베어링강의 마찰거동에 미치는 마모입자의 영향에 대한 실험적 고찰 (An Experimental Study on the Effect of Wear Particles on the Sliding Behavior of Silver-Coated Bearing Steels)

  • 양승호;공호성;윤의성;김대은
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
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    • pp.59-66
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    • 2000
  • An experimental study on the effect of silver particles on the sliding behavior of bearing steels was performed by using a ball-on-disk tribometer. Tests were carried out in ambient air, dry and vacuum. Disks of AISI 52100 were silver-coaled by a thermal evaporation method, and the effects of silver particle transfer on friction were firstly analyzed. In order to understand further the mechanism of silver particles transfer and its effect on friction and wear, pre-compressed silver particles were artificially introduced into the friction interface and the results were compared to those of silver-coated specimens. Results showed that the introduced silver particles produced transfer layers and resulted in low friction. It also showed that this low friction is closely related to the characteristic behavior of transfer layers. Shakedown and rachetting occurred at the friction interface and affected the friction and wear.

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나노 크기의 실버 및 글래스 분말로부터 형성된 실버 전극의 특성 (Characteristics of Silver Electrode Formed from Nano-Sized Silver and Glass Powders)

  • 구혜영;김정현;이장희;고유나;강윤찬
    • 대한금속재료학회지
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    • 제48권6호
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    • pp.570-574
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    • 2010
  • Silver conducting films were formed from nano-sized silver powders and glass frits prepared by flame spray pyrolysis. The mean sizes of the silver powders and glass frits were 73 and 63 nm, respectively. Nano-sized glass frits improved the adhesion strength of the silver conducting film to the glass substrate. The densities of the silver conducting films increased by increasing the glass contents of the films at firing temperatures of 400 and $500{^{\circ}C}$. The specific resistances of the silver conducting films with 5 wt.% glass of silver component were 7.8, 4.2 and 2.4 cm at firing temperatures of 400, 450 and $500{^{\circ}C}$.

Chloride ion removal effect for the ACF electrochemically treated with silver

  • Oh, Won-Chun;Park, Choung-Sung;Bae, Jang-Soon
    • 분석과학
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    • 제19권4호
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    • pp.316-322
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    • 2006
  • The removal efficiencies of silver-ACFs were associated with their surface properties such as surface area, porosity, and the electro-chemical reaction time for the silver treatments. X-ray diffraction patterns of fibers electrochemically treated with silver display diffraction peaks for metallic silver and kinds of silver chloride complexes on the fiber surface after electrochemical adsorption. The results of SEM and EDX indicate that surface reaction motive of silver-ACF prepared by electrochemical reaction are depend on time function for the chloride ion removal efficiency. Finally, Cl ion adsorbed by the silver-ACFs from the ICP analysis seems to show an excellent removal effect.