• Journal of the Microelectronics and Packaging Society
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• v.23 no.3
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• pp.51-56
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• 2016

To fabricate a copper (Cu)-based fine conductive filler having antioxidation property, submicron silver (Ag)-coated Cu particles were fabricated and their antioxidation property was evaluated. After synthesizing the Cu particles of $0.705{\mu}m$ in average diameter by a wet-reduction process, Ag-coated Cu particles were fabricated by successive Ag plating using ethylene grycol solvent. Main process parameters in the Ag plating were the concentration of reductant (ascorbic acid), the injection rate of Ag precursor solution, and the stirring rate in mixed solution. Thus, Ag plating characteristics and the formation of separate fine pure Ag phase were observed with different combinations of process parameters. As a result, formation of the separate pure Ag phase and aggregation between Ag-coated Cu particles could be suppressed by optimization of the process parameters. The Ag-coated Cu particles which were fabricated using optimal conditions showed slight aggregation, but excellent antioxidation property. For example, the particles indicated the weight gain not exceeding 0.1% until $225^{\circ}C$ when they were heated in air at the rate of $10^{\circ}C/min$ and no weight gain until 75 min when they were heated in air at $150^{\circ}C$.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.7
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• pp.665-675
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• 2010

The effects of chemical binders (ladle slag, ordinary portland cement (OPC), hydroxyapatite and calcium hydroxide) on the solidification/stabilization of heavy metals (Cd, Cu, Ni, Pb, Zn) in sewage sludge were evaluated by chemical leaching tests such as EDTA extraction, TCLP and sequential extraction. The results of EDTA extraction showed that heavy metal concentrations in sewage sludge were highly reduced after solidification/stabilization with slag, cement or calcium hydroxide. However, EDTA interrupted solidification/stabilization of heavy metals by hydroxyapatite. The TCLP-extracted heavy metal concentrations in sewage sludge after solidification/stabilization with chemical amendments were highly reduced. However, Cu concentration in the sewage sludge solidified/stabilized with slag, cement or calcium hydroxide increased because the pH of TCLP solution was higher than 7. Mixtures of sludge 1 : slag 0.2 : calcium hydroxide 0.1 (wt ratio) showed the least leachability in batch TCLP and EDTA extraction. The results of sequential extraction (SM&T, formaly BCR) indicated that the distribution of heavy metals changed from exchangable and carbonate fractions to strongly bound organic fraction. It was found that maximum leachate concentrations of Ba, Cd, Cr and Pb from sewage sludge amended with slag and calcium hydroxide were far below US EPA TCLP regulations.

• Microbiology and Biotechnology Letters
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• v.18 no.5
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• pp.466-470
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• 1990

Aflatoxin $B_1$ ($AFB_1$) was reacted with ascorbic acid (AA) alone, with AA plue cysteine and with AA plus cupric ion for 5 days (at $37^{\circ}C$ and pH 5), and the mutagenicity of the reaction products was tested with Salmonella typhimurium TA 100. About 10% of AFBl induced mutagenesis was reduced when $AFB_1$ reacted with AA. This decreasing effect was more severe when $AFB_1$ reacted with AA plus cysteine. The mutagenicity of $AFB_1$ when reacted with AA plus cupric ion was almost completely inhibited, however, eupric ion itself was shown to enhance the mutagenicity of $AFB_1$. Therefore, $AFB_1$ may be degraded in the presence of AA under the given reaction condition and the reaction products was observed to have nonmutagenic effects on the bacterial mutagenecity trials.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.398-399
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• 2001

A fungus. Penicillium sp. PS-113. with high phosphate-solubilizing activities was isolated from soil and tested the viability in POA medium supplemented with various concentrations of Trio in order to develop a dispersing agent for liquid formulation. Moreover, the number of Penicillium sp. PS-113 conidia, stored at $4^{\circ}C$ and $25^{\circ}C$ with Trio(0.1%) and various concentrations of additives($Cu^{++}$ $Mo^{++}$, bio-ceramic, Tween 80, PEG 200. diatomite. SDS), was counted on PDA at the intervals of 2 weeks. As a result, the liquid formulation containing 0.1 %( v/v) Trio was remarkably improved in dispersing ability and the viability of the conidia, and each of the supplements (0,01% $Mo^{++}$, 0.5% bio-ceramic. 1.0% Tween 80, 1.0% PEG 200) was similar to the 0.1% Trio.

• Korean Journal of Materials Research
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• v.7 no.1
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• pp.81-88
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• 1997

Vanadate glasses using $B_2O_3$ as a network former and with CuO additive were mainly investigated in relation to electrical properties. Crystalline phases formed by heat-treatment in each composition were examined and dc electrical conductivity changes of the glasses were analyzed. Crystalline phases were identified as $V_3O_5,\;a-CuV_2O_6\;and\;{\beta}-CuV_2O_6$ by XRD analysis. Crystallization degrees of $V_2O_5$ and ${\beta}-CuV_2O_6$ were little changed with heat-treatment time, but those of ${\alpha}u-CuV_2O_6$ were changed sharply with heat-treatment time. The more crystallization of ${\alpha}u-CuV_2O_6$ occurred, the higher electrical conductivity was observed. Electrical conductivities with $10^{-2}~10^{-4}/{\Omega}/cm$ at room temperature(303K) could be obtained by controlling the glass compositions. The electrical conductivities were increased with increasing of $V_20_5$ content and decreasing of alkality($CuO/B_2O_3$). In this study, electron was proved to be charge carrier by seebeck coefficient measurement. Accordingly, the glasses are believed to be n-type semiconductor. Calculated activation energies for the conduction were in the range 0.098-0.124 eV. Electrical conduction mechanism was small polaron hopping without showing variable range hopping in the temperature range $30~200^{\circ}C$.

• Nuclear Engineering and Technology
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• v.8 no.2
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• pp.89-99
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• 1976

The grafting of acrylic acid in aqueous solution to polyvinyl chloride fibers tab been studied in the presence of ferrous, ferric, and cupric salts, The mutual irradiation technique was adopted using a Co-60 source or a Van do Graaff accelerator. The grafting and homopolymerization were suppressed by the cations. Particularly the grafting was suppressed by the cations in the following order of effectiveness : $Cu^{2+}$>$Fe^{2+}$>$Cu^{3+}$. The rate of grafting (in %/hr) was proportional to the 0.76th power of the dose rate over the range from 8.5f $10^3$ rad/hr to $1.4\times10^5$ rad/dr. The apparent activation energy for the grafting was determined to be 6.1 Kcal/mole between $25^{\circ}$ and $75^{\circ}C$ for the mixture of AA-HaO-$(CH_2Cl)_2$, containing Mohr's salt, $4\times10^{-3}$ mole/l. The increase of the grafting was observed when total dose and dose intensity were raised, or when ethylene dichloride as a swelling agent was saturated in the monomer mixture. The grafted polyvinyl chloride fibers showed considerable improvement in moisture regain, heat shrinkage, and melting properties, but tensile properties were not significantly affected by grafting.

• Journal of Conservation Science
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• v.35 no.5
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• pp.508-517
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• 2019

This study analyzed on alloys and by-product samples produced through the reproduction experiment of bronze mirror with geometric designs. The alloy ratio used in the first and second reproduction experiments was based on the analysis results of bronze mirror with geometric designs(Cu 61.68%, Sn 32.25%, Pb 5.46%) which is the national treasure No. 141. As a result of portable X-ray fluorescence analysis on the raw materials used in the reproduction experiment, the contents of copper raw materials were 98.85 wt% for Cu, tin raw materials were 99.03 wt% for Sn, and lead raw materials were 70.19 wt% for Pb, and 21.81 wt% for Sn. Sn and Pb were added 5 wt% more considering the evaporation amount of tin and lead during alloy melting. The result produced by the first reproduction experiment were 58.75 wt% for Cu, 36.87 wt% for Sn, 4.39 wt% for Pb, and the other result produced by the second reproduction experiment were 58.66 wt% for Cu, 35.89 wt% for Sn, and 5.50 wt% for Pb. The composition of the components was about 3.00 wt% in Cu and Sn respectively, and the microstructure was similar to the previous studies because the δ phase was observed mainly. The results of this study will be used as basic data for the materialistic characteristics of ancient bronze mirror in the future.

• Journal of the Korean Chemical Society
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• v.37 no.4
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• pp.416-422
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• 1993

As a result of adsorbing phthalocyanine (metal free, ${\alpha}\;and\;{\beta}$-Cu) on zinc oxide in aqueous solution using nonionic surfactant, all of the added dye was adsorbed and Na salt of sulfonated phthalocyanine showed the Langmuir monolayer adsorption. To analyze the effect of adsorption on zinc oxide, photovoltage was measured using surface photovoltmeter. The high photovoltaic effect was observed at intrinsic wavelength of zinc oxide and wavelength of adsorbed phthalocyanine dye. Metal free phthalocyanine, ${\alpha}$-copper phthalocyanine and ${\beta}$-copper phthalocyanine showed the highest photovoltaic effect when the percentage of coverage (${\theta}_{BET}$) for zinc oxide is about 80, while sulfonated phthalocyanine showed the highest photovoltaic effect when the percentage of coverage for zinc oxide is about 30.

• Journal of Surface Science and Engineering
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• v.43 no.1
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• pp.41-45
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• 2010

The effect of $MoS_2$ and graphite content on wear resistance and mechanical properties of Cu/Sn bonded diamond micro blades was comparatively investigated in terms of volume and weight fraction. For the evaluation of endurance and cutting performance, instantaneous electric power consumption and cumulative wear loss during cutting glass work piece at constant velocity were measured with the micro blades of the wide range of lubricant content. The energy consumption of blades for glass cutting decreased with the content of lubricants. Wear amount of blade in volume increased with the amount of lubricant addition. It was found to be relevant to the decrease in flexural strength and hardness with the amount of lubricants. With the same amount of lubricant content in volume fraction $MoS_2$ showed superiority in mechanical properties and cutting performance than graphite while graphite could result in stronger effect on lowering electric consumption during cutting work piece for the same weight percent fraction than $MoS_2$ because of lower density.

• Journal of Environmental Health Sciences
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• v.33 no.1 s.94
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• pp.75-81
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• 2007

This research was conducted to estimate the effect of sonication and reducing agent addition on soil washing of heavy metals-contaminated soil. Sonication trained in soil washing did not significantly increased extraction efficiency of heavy metal compared to soil washing only. The extraction efficiency of sonication trained in soil washing was 12% increased for Pb in 0.01M EDTA leaching solution. Pb and Cd showed higher extraction efficiency in case of reducing agent treatment with mechanical shaking than that with sonication. However, the extraction efficiency of Cu and Zn in case of reducing agent treatment with sonication was over 2 times higher than that in with soil washing. Therefore, application of reducing agent addition with sonication or mechanical shaking should be decided differently for pretreatment of soil washing, according to the kind of heavy metal. It was estimated that sonication after adding reducing agent could increase removal efficiency of Zn or Cu-contaminated soil and shorten the treatment time.