• Journal of the Korean Applied Science and Technology
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• v.25 no.2
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• pp.168-174
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• 2008

This study is focused on the antimicrobial activity of cyanobacteria Microcystis aeruginosa by the reduction and oxidation reaction of copper and zinc alloy metal fiber filter. Cu/Zn ion is easily makes radicals with molecular hydroperoxide. Especially, hydroperoxide radical shows strong toxicity to the strains. Plasma membrane causes conformational change when hydroperoxide radical binds to plasma membrane. Elution of copper ion from copper and zinc alloy metal fiber is detected in the cyanobacteria solution as 0.5 ppm, and that of zinc ion is 0 ppm respectively. Zinc ion is figured to form a hydroxide in the cyanobacteria solution and precipitated to form a sludge. The concentration of chlorophyll-a in the cyanobacteria solution was proved to be the index of antimicrobial level of Microcystis aeruginosa.

• Journal of the Korean Society for Heat Treatment
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• v.26 no.4
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• pp.173-177
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• 2013

Separation and recovery of valuable metals such as zinc, nickel or tin from copper alloy dross has recently attracted from the viewpoints of environmental protection and resource recycling. In this report, preliminary study on concentration and separation of tin from copper alloy dross using selective dissolution method was performed. The tin in the copper alloy dross did not dissolve in the nitric acid solution which could allow the concentration and separation of the tin from the copper alloy dross. Precipitation of tin as $H_2SnO_3$ (metastannic acid) occurred in the solution and transformed to tin dioxide ($SnO_2$) after drying process. The dried sample was heat-treated at low temperature and its phase characteristics, surface morphology and chemical composition were investigated.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.2
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• pp.84-87
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• 2014

Separation/recovery of valuable metals such as zinc, nickel or tin from copper alloy dross has recently attracted from the viewpoints of environmental protection and resource recycling. In this study, preliminary investigation on separation of tin (Sn) from copper alloy dross using selective dissolution method was performed. The tin in the copper alloy dross did not dissolve in an aqueous nitric acid solution which could allow the concentration/separation of tin from the copper alloy dross. Precipitation of tin as $H_2SnO_3$ (meta stannic acid)occurred in the solution and transformed to tin dioxide ($SnO_2$) after drying process. The dried sample was heat-treated at low temperature and its crystal structure, surface morphology and chemical composition were investigated.

• The Korean Journal of Malacology
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• v.30 no.4
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• pp.353-361
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• 2014

In order to investigate the effects of copper alloy on abalone physiology, we studied survival rate, respiration, excretion rate, and heavy metal accumulation in each organ of adults and spats. The survival rate of spats and adults showed 27-60% and 63-83% respectively, higher survival rate in adults. In particular, 100% of copper panel led to lowest survival rate and there was no sharp distinction according to copper alloy composition. The respiration rate and excretion rate of ammonia nitrogen was $1.81mgO_2/g$ D.W./h and 0.43 mg $NH_4-N/g$ D.W./h respectively at 100% of copper panel. In other words, there was a high significant difference at the level, but no significant difference at other test levels (P < 0.05). The atomic ratio (0: N) hit the lowest at the 100% of copper panel showing 3.79 and no significant differences were seen among other test groups with 6.57-7.18 of a very low range. This means that the species might have undergone nutritional stress. In case of copper accumulation, the 100% copper panel group showed the highest level in hepatopancreas and muscle showing 6.91 mg/kg and 1.60 mg/kg respectively but the rest of groups showed similar levels. Zinc accumulation raised at Cu-Zn alloy panel had high significance showing 18.50 mg/kg and 1.10 mg/kg in hepatopancreas and muscle respectively (P < 0.05). To sum up, a cage net made of 100% pure copper is expected to have a negative effect on abalone in light of survival rate, heavy metal accumulation, and atomic ratio (0: N). Moreover, given that the substratum used for the high adhesive species and nutritious stress that is represented through the atomic ratio need to be considered, the copper alloy net is thought not to be suitable for abalone aquaculture.

• Corrosion Science and Technology
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• v.15 no.6
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• pp.311-313
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• 2016

The anodic dissolution behavior of copper and brass in an electrolyte solution of 0.5M NaCl containing 0.5 mM $NaHCO_3$ was investigated by electrochemical impedance spectroscopy. The Nyquist plots of the copper impedance described a small loop in the high-frequency range and a large locus in the low-frequency range. Additionally, the features of the impedance spectrum of the brass were similar to those of the copper. This indicates that the copper-enriched layer formed on the brass surface due to the selective dissolution of the zinc from the surface. In addition, the rest potential and the anodic polarization curve for each sample were measured in order to discuss the selective dissolution of the zinc from the brass surface.

• Korean Journal of Ichthyology
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• v.26 no.3
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• pp.159-170
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• 2014

The effect of substances discharged from copper alloy mesh on the survival rate, growth, and health status of Sebastes schlegeli was investigated. Survival rate of experimental group was 10% higher than control group. There was no significant difference in weight gain and SGR between control group and experiment group (P<0.05). Glucose concentration was lower in the experimental group than that in the control group. GOT and GPT contents did not show significant difference during experiment except for the early three months of experiment (P<0.05). Ammonia concentration had not significantly changed in the experimental group, but it had increased until four months of experiment and then decreased afterwards in the control group. TCHO had decreased in the experiment group compared with that of control group. Copper and zinc contents had increased as compared with those in the initial stage of experiment with no significant difference between experiment group and control group (P<0.05). Histological analysis for the liver revealed that liver tissues were not particularly different from those in control group. There were no significant differences in survival rate, growth, and hematological characteristic between control group and experiment group (P<0.05). Though copper and zinc were accumulated as compared with those during the initial stage of experiment, the levels were lower than permissible levels for copper and zinc. As a result, copper alloy mesh would not adversely affect on the survival rate, growth, and health status of fishes.

• Journal of Adhesion and Interface
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• v.24 no.3
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• pp.105-111
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• 2023

Recently, there has been a growing interest in low biofouling coatings for various industrial applications including precious metal and jewelry applications. Contaminations including cells and bacteria of the metallic substrates (i.e., accessories, earring, and piercings) may irritate the contacted tissue surfaces or induce an abnormal reaction. In this study, catechol-conjugated polyethylene glycol (PEG-C) was synthesized as low bio-fouling coating materials inspired by mussel-adhesion. PEG-C-coated copper-zinc alloy surfaces showed excellent cell viability and significant inhibitions of protein and cell adhesions to metal surfaces. Thus, PEG-C coating methods and PEG-C-coated metallic substrates can be usefully exploited for versatile industrial applications, particularly for precious metal and jewelry industries.

• Korean Journal of Heritage: History & Science
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• v.52 no.3
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• pp.38-55
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• 2019

The purpose of this study is to clarify the historical flow of baekdong alloy's usage according to the alloying materials mentioned in document records. For this purpose, we first overviewed the use of copper as a base material for white copper alloys and other types of copper alloys. Baekdong is an alloy of copper and other metals and is currently defined as an alloy of copper and nickel. However, depending on the research subjects and time of the scholars, baekdong may be defined as a metal with over a certain percentage of tin added to copper, or as an alloy of tin, zinc, and lead with copper. There is disagreement regarding the interpretation of this term. Baekdong, which started to appear in the literature of the Three Kingdoms Period, has been steadily seen through the Goryeo and Chosun Dynasties to the modern period. It has been used in various ways, according to each age and culture, from the symbol of the office to trading goods, daily life goods, and money. In the literature, baekdong's alloying material is not only copper and nickel, which are currently defined as alloys, but it is the same in that copper is used as the base metal of the alloy, although it varies slightly from generation to generation. In addition to copper, tin, zeolite, and emerald, zinc and lead also appeared. It was found that baekdong, which means alloy, and baekdong, which means white metal, were mixed. Nickel, which is the alloy material of baekdong as it is currently defined, is a metal with a relatively high discovery time and is widely used as a material for modern industrial fields. Nickel was introduced into Korea at the end of the Joseon Dynasty, but its use is not known in detail. In this study, we examined the acceptance and use of nickel-based baekdong in articles of modern newspapers and in statistical data. Based on the experience of craftsmen, we estimated the period when nickel-based alloys were used in crafts. Material is a direct factor in the development and deterioration of technology, and the development of technology is the basis for the changing of civilizations and cultures. In this context, this study was to investigate baekdong with the material of alloys as a starting point.

• Corrosion Science and Technology
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• v.7 no.2
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• pp.125-129
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• 2008

Results of corrosion testing for different grades of titanium, copper, zinc, alluminium alloys and steels after two years of outdoor exposure under humid tropical urban and marine conditions have been presented and discussed. Mass loss and corrosion product characteristics for the exposed specimens at Hanoi testing site with high humidity and Nhatrang marine stations (at 100 and 1,000 meters distances from sea) with different airborne salinities (35.9 and $90.0mg/m^2.d$ respectively) have been selected for investigation. From time dependence of the specimen mass loss and corrosion product characteristics, the strong influence of environmental parameters upon durability for the investigated metals and alloys has been demonstrated. Only titanium alloys show high resistance to the marine conditions. All the other specimens (copper, zinc, alluminium alloys and steels) have been underwent strong deterioration under influence of aerosol salinity. Results of corrosion products analysis have been also presented for characterization of environmental impact on the metal degradation processes.

• Journal of Conservation Science
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• v.36 no.3
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• pp.178-186
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• 2020

Verdigris is a traditional artificial pigment reported on old research papers and according to the methods mentioned in the literature, it is manufactured by the corrosion of copper or copper alloys using vinegar and by further scraping the generated rust. Since the Three Kingdoms Period, various household products with copper alloys, such as bronze and brass, have been used, and pigment analysis of these cultural heritage items has revealed the presence of tin, zinc, lead, and copper in green pigments. Based on these data, five types of verdigris were prepared from copper and copper alloys, and analyzed. the analysis results revealed a bluish green pigmentation, and the chromaticity, particle shape, and oil absorption quantity of each verdigris differed based on the type of copper alloy used in its preparation. The main components of verdigris are Cu, Sn, Zn and Pb, and their proportions depended on the type of copper alloy used during manufacturing. However, the main constituent mineral of the pigments is the same as 'hoganite[Cu(CH₃COO)₂·H₂O]', regardless of the copper alloy used. The result of accelerated weathering test for stability evaluation revealed that verdigris was discolored rapidly, thereby indicating that its stability was low, in particular, the pigments comprising lead presented relatively lower stability.