• Journal of the Korean Electrochemical Society
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• v.8 no.1
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• pp.17-23
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• 2005

The electrochemical behaviors of polycrystalline silver electrodes in 8M KOH solutions containing $Bi_2O_3$ were studied under various conditions by cyclic voltammetry, potentiostatic and galvanostatic techniques as well as the morphology of the silver oxide structures by SEM. It was found that three new compounds comprising silver, bismuth, and oxygen as well as $Bi_2O_3$, $Ag_2O$ and AgO were formed during the electrochemical oxidation of silver. In addition, the potentiostatic current transients were characterized by the appearances of the first current peaks corresponding to the formation of silver oxides, and the second current peaks corresponding to the Ag-Bi-O compounds, indicating the presence of the nucleation and 3D growth mechanism, in the potential regions of $Ag_2O$ and AgO, respectively. Microscopic examinations showed that two types of silver (I) oxide morphologies are formed in the potential region of $Ag_2O$.

• Journal of the Korean Chemical Society
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• v.17 no.5
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• pp.319-323
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• 1973

The state of carrier-free silver-111 has been studied by applying filtration method. The studies involved that the effects of pH and concentration of silver-111 in aqueous solution have been determined with membrane filters. The present studies revealed that the retainment of silver-111 on membrane filters followed Freundlish adsorption isotherm, and the adsorbed state of silver-111 was present in the form of AgOH. Also it was supposed that the formation of the non-adsorbed hydroxide of$Ag(OH)_{2}-$ may prohibit the existance of AgOH at higher pH, and it seems to be valid that the carrier-free silver-111 in aqueous solution exists in$Ag^+$state.

• Journal of Powder Materials
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• v.12 no.1
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• pp.56-63
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• 2005

Ag powder was prepared from $AgNO_3$ by wet chemical reduction method using various reduction agent system involving $AgNO_3$, $AgNO_2$(AgCl) and Ag complex ion aqueous solution. The pure Ag powder could be prepared regardless of reaction system but the particle shape and distribution were affected very much according to the kind of reduction agents and reaction systems. The optimum reaction system for the preparation of the silver powder having the uniform particle shape and size distribution was Ag complex ion aqueous solution-reduction agent system and in particular, $H_2O_2$ and $C_6H_8O_6$as a reduction agent leaded the more uniform particle shape and size distribution.

• Journal of the Korean Chemical Society
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• v.30 no.6
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• pp.500-509
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• 1986

For the development of new type cell, a study on new electrolyte, $AgI-Ag_8S_3SO_4$ system has been carried out by using electrical conductivity measurement, DTA and X-ray powder diffraction method. From both X-ray powder diffraction and DTA method, it is clearly known that 20mole% $ Ag_8S_3SO_4$-AgI system forms single phase, having monoclinic structure. It is also found that 20mole% $Ag_8S_3SO_4$-AgI system is purely $ Ag^+ $cation conduction from results of conductivity measurement by applying 4-probe method.

• Resources Recycling
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• v.5 no.1
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• pp.29-33
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• 1996

The cominnn plocesses lor rccoremg silver irom silvcr conlaincd waster are the lcachmg silver hy HNO;. the srlcctive precipilillion of sliver ion lo AgCl and thc rcduchon of Ag wrfh ;I proper reductant. In this sludy, thc reduction of AgCI lo Ag was invesllngated by using Na, CO, as a rcd\icta~lt. The variations wcic reaction time. ttmpcrarure thc amount of NalCO, . and the resulls %, ere analyzcd by using sialist~c:d tecl~niques such as the ]polynomial rcgressiun analysis and the response surh~ce method. More than Yh% Ag analyzed was rcduced 1rtm AgCI at 62UT. I hour ullder condillon of 2 stnlchio~nctric ratio of Na iCO, !AgCI.

• Bulletin of the Korean Chemical Society
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• v.21 no.10
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• pp.953-954
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• 2000

The equilibrium geometrical structures of silver atom clusters at their electronic ground states have been theo-retically determined by using the nonrelativistic semiempirical INDO/1 method. The clusters investigated are Agn, Agn+, and Agn- (n = 7 , 8, 9). In order to find the most stable structure, i.e., the global minimum in energy hypersurface, geometry optimization and energy calculation processes have been repeatedly performed for all the possible graphical models by changing the bond parameters (resonance integral values). The heptamers are pentagonal bipyramidal-Ag7(D5h), Ag7+ (D5h), Ag7- (D5h); the octamers are pentagonal bipyramidal with one atom capped-Ag8(D2d), Ag8+ (Cs), Ag8- (D2d); the nonamers are pentagonal bipyramidal with two atoms capped -Ag9(C2v), Ag9+ (C2v), Ag9- (C2v). Our structures are in good agreement with those by ab initio calculations ex-cept for the anionic Ag9- cluster. And it is noted that the INDO/1 method can accurately predict the Ag cluster geometries when a proper set of bond parameters is used.

• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.100-104
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• 2019

The 'ITO/Ag/ITO' multilayers as a highly conductive and transparent electrode, even with the optimum thickness conditions, the transmittances were much lower than those of a single ITO layer on some ranges of the visible wavelength. In order to improve the transmittance, Ag layer was formed with mesh structure. Where, the thickness of the Ag layer was about 10 nm and the space between the Ag lines was varied from 2.9 ㎛ to 19.6 ㎛ with the fixed Ag width of about 1.2 ㎛ in order to vary an open ratio of the Ag mesh structure. The transmittance and sheet resistance in the ITO/Mesh-Ag/ITO multilayer structure were analyzed depending on the open ratio. As a result, a trade off in the open ratio was necessary in order to obtain the transmittance as high as possible and the sheet resistance as possible low. By the open ratio of about 86%, in the ITO/Mesh-Ag/ITO multilayer structure, the transmittance was nearly same as the single ITO layer and the sheet resistance was about 62.3 Ω/.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.4
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• pp.65-71
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• 2017

To prepare the Cu-based filler material indicating enhanced oxidation resistance property and Ag content, Ag-coated Cu particles was fabricated by Ag plating of 40 wt % on the spherical Cu particles with an average size of $2{\mu}m$ and their oxidation behavior was also evaluated. In the case that ethylenediaminetetraacetic acid was used alone, the fabricated particles frequently showed broken structures such as delamination at Ag shell/core Cu interface and hollow structure that are induced by excessive galvanic displacement reaction. As a result, fraction of defect particles increased up to 19.88% after the Ag plating of 40 wt.%. However, the fraction in the 40 wt.% Ag-coated Cu particles decreased to 9.01% and relatively smooth surface and dense microstructure in the Ag shell were also observed with additional usage of hydroquinone as a complexing agent. Ag-coated Cu particles having the enhanced microstructure did not show any weight increase by oxidation for exposure to air at $160^{\circ}C$ for 2 h, indicating increased oxidation resistance property.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.1
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• pp.1-9
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• 2005

A stoichiometric mixture of evaporating materials for AgGaS₂ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, AgGaS₂ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were 590℃ and 440℃, respectively. The temperature dependence of the energy band gap of the AgGaS₂ obtained from the absorption spectra was well described by the Varshni's relation, E/sub g/(T) = 2.7284 eV - (8.695×10/sup -4/ eV/K)T²/(T + 332 K). After the as-grown AgGaS₂ single crystal thin films was annealed in Ag-, S-, and Ga-atmospheres, the origin of point defects of AgGaS₂ single crystal thin films has been investigated by the photoluminescence (PL) at 10 K. The native defects of V/sub Ag/, V/sub s/, Ag/sub int/, and S/sub int/ obtained by PL measurements were classified as a donors or accepters type. And we concluded that the heat-treatment in the Ag-atmosphere converted AgGaS₂ single crystal thin films to an optical n-type. Also, we confirmed that Ga in AgGaS₂/GaAs crystal thin films did not form the native defects because Ga in AgGaS₂ single crystal thin films existed in the form of stable bonds.

• Korean Journal of Environmental Biology
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• v.20 no.2
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• pp.136-145
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• 2002

A laboratory microcosm experiment was conducted to evaluate a major metal uptake route as well as chronic toxic effects of the clam, Macoma balthica exposed to Ag and Cu contaminated sediments. Twenty five clams were exposed to the sediments contaminated with four levels of Ag $Ag(0.01-0.87\mu{mol}\;g^{-1})$ and $Cu(0.75-5.55\mu{mol\;g^{-1})$ for 90 days. AVS (acid volatile sulfide) concentration in the sediments, considered as major factor controlling metal geochemistry and bioavailability, was manipulated to evaluate its effects on Ag and Cu bioaccumulation in M. balthica. Following 90-d exposure, the tissue Ag and Cu in M. balthica increased linearly with the Ag and Cu concentrations in sediments extracted with 1 N HCI (SEM, simultaneously extracted metals with AVS). The bioaccumulation of Ag and Cu in M. balthica was little influenced by difference in [SEM] - [AVS] values, suggesting a minor contribution of pore water metals to bioaccumulation. Tissue Ag and Cu concentrations directly influenced on the clearance rate and glycogen content of the clams. The clams with highest tissue Ag $(1.0\pm{0.2}\mu{mol}\;g^{-1})$ and Cu concentrations $(2.7\pm{0.3}\;\mu{mol}\;g^{-1})$ had only 18-43% of clearance of the clams exposed to uncontaminated sediments. Similarly, glycogen content of the exposed clams had a inverse relationship with tissue Ag and Cu concentrations. These results suggest that M. balthica exposed to Ag and Cu contaminated sediments accumulates metals largely by ingestion of contaminated sediments and can display chronic effects as reduced clearance rate and glycogen content.