• Journal of Korean Society on Water Environment
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• v.20 no.3
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• pp.265-268
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• 2004

Larva of Carassius auratus and Pungtungia herzi were exposed to mercury ($HgCl_2$), lead ($PbCl_2$) and copper ($CuSO_4$) to determine acute toxicity. The toxicity tests were conducted triplicate and the $LC_{50}$ values (24, 48, 72 and 96 hours) were determined for two species. Data obtained from the toxicity tests were evaluated using the probit analysis. Although sensitivities of two species to mercury were relatively similar, C. auratus was more susceptible than P. herzi to the exposure of lead but P. herzi was more sensitive than C. auratus on copper. The sensitivity on three metals tested may be ranked in the following order from highest to lowest toxicity on larval stage of these fish: mercury > copper > lead. It is suggested that acute toxic test at the larval stage of C. auratus and P. herzi, indigenous species in Asia area, is an important part of the ecotoxicological assessment of some heavy metals.

• Journal of Environmental Health Sciences
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• v.19 no.3
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• pp.22-28
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• 1993

In order to investigate the hygienic chemical conditions of farm waters used as the potable and cleaning water for cow, we examined the pH, turbidity, KMnO$_4$ consumption, total hardness, chlorine, sulfate, NH$_3$-N, NO$_3$-N, lead, maganese, copper, zinc, fluoride and chrome for 78 farm waters around Kyunggi Province. Of 78 farm waters tested, average pH was 6.70+_0.06, turbidity 0.724 $\pm$ 0.081, KMnO$_4$ consumption 4.200 $\pm$ 0.256 mg/l, total hardness 107.46 $\pm$ 6.90 mg/l, NH$_3$-N 0.043 $\pm$ 0.037 mg/l, NO$_3$-N 8.096 $\pm$ 0.652 mg/l, chlorine 21.414 $\pm$ 2.187 mg/l, sulfate 12.737 $\pm$ 1.511 mg/l, lead 0.076 $\pm$ 0.001 mg/l, manganese 0.029 $\pm$ 0.004 mg/l, copper 0.018 $\pm$ 0.002 mg/l, zinc 0.055 $\pm$ 0.005 mg/l, chrome 0.048 $\pm$ 0.002 mg/l and fluorine 0.011 $\pm$ 0.001 mg/l. According to the geological characteristics, the concentrations of total hardness, NO$_3$-N, pH and chlorine in farm waters of Hwasung gun were higher than those in Yangpyung and Kwangju gun. In hygienic chemical items tested, there were high significanc among NO$_3$-N, total hardness, sulfate and chlorine. KMnO$_4$ consumption was significant with NH$_3$-N, sulfate and pH. But in heavy metals, there were significance between lead and copper, copper and chrome, and copper and fluorine.

• The Korean Journal of Ecology
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• v.23 no.1
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• pp.59-64
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• 2000

Heavy metal concentrations in surface sediments, seawater and oysters (Crassostrea gigas) were determined to assess heavy metal contamination in the Jinhae Bay. The ranges of cadmium, cobalt, copper, nickel, lead and zinc concentration in surface sediments were 0.1∼2.4, 12.6∼14.4, 25.3∼ 92.3, 32.4∼ 93.5, 24. 1∼81.2, 124∼477 ㎍/g, respectively. The concentrations of cadmium, copper, lead and zinc which were influenced by industrial activity were the highest in the inside of Masan Bay. Dissolved concentrations of cadmium, cobalt, copper, nickel, lead and zinc in seawater were <0.010∼0.043, 0.008∼0.120, 0.31∼0.90, 0.25∼3.10, 0.010∼0.142, 0.27∼9.04 ㎍/L, respectively. The concentrations of cadmium, cobalt, copper, nickel, lead and zinc in seawater were also the highest inside of Masan Bay, suggesting that Masan Bay is the major source of heavy metal input to the Jinhae Bay. Bioconcentration factors (BCF) of zinc, copper, cadmium, lead, cobalt and nickel in C. gigas were 647373, 280861, 145069, 44559, 13524, 2745, respectively, showing C gigas is a stronger accumulator than other bivalves.

• Journal of Korea Foundry Society
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• v.20 no.1
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• pp.3-12
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• 2000

The lead content of drinking water has been restricted to less than 15 ppb by Environmental Protection Agency (EPA) in USA. This has led to extensive research and development work at the Materials Technology Laboratory (MTL) of CANMET, a Canadian Government research laboratory, on the development of low-lead and lead-free copper alloys for plumbing applications. Attentionhas also been focused on the environmentally friendly and energy efficient permanent mold casting process to minimize the disposal of foundry sand contaminated by lead due to the use of leaded alloys in the non-ferrous foundries. A new series of alloys called SeBiLOY contaning Bi and Se been introduced to replace lead in the leaded alloys. This paper addresses some important casting characteristics such as fluidity, hot tear resistance, mechanical properties and microstructure of lead-free alloys such as SeBiLOY III and low-lead alloys such as silicon brass, silicon bronze and yellow brass in gravity permanent mold casting.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.131-136
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• 2001

In this paper, a high-temperature superconductor(HTS) current lead operating in current sharing mode is described. The minimum heat dissipation and the optimum safety factor(cross-sectional area) is obtained analytically for partial current sharing HTS leads. It is assumed that the current lead is in conduction cooled state, and the sheath material is the alloy of silver and gold. The reduced cross-sectional area results partial current sharing state, and consequently reduces conduction heat transfer, but the Joule heat generation is increased. The optimized HTS current lead is different from the conventional copper leads. In the copper leads, the minimum heat dissipation is obtained for the zero gradient of temperature at warm end. However, the temperature gradient at warm end is not zero when the HTS lead operates at minimum dissipation state.

• Korean Journal of Veterinary Research
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• v.25 no.2
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• pp.145-148
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• 1985

Nickel toxicity and interactions of nickel with zinc, copper, and lead were studied in glowing chicks fed supplemented diet. Feed intake and growth rate of the chick were reduced by 250mg nickel as a sulfate salt per kg of feed. The toxicity of nickel was decreased by zinc or copper supplementation, but not lead. High nickel feed increased nickel level in kidney and decreased zinc levels in tibia and plasma. However, low zinc levels in tibia and in plasma were reversed by zinc supplementation. Hemoglobin, packed cell volume, and aortic elastin content were increased in chicks fed nickel. These results suggest that nickel toxicity is induced by interference with zinc metabolism.

• Tribology and Lubricants
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• v.21 no.2
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• pp.71-76
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• 2005

This paper compares of mechanical tensile properties of 6 kinds of copper foil. The beam lead made with copper foil. Different from other package type such as plastic package, Chip Size Package has a reliability problem in beam lead rather than solder joint in board level. A new tensile loading system was developed using voice-coil actuator. The new tensile loading system has a load cell with maximum capacity of 20 N and a non-contact position measuring system based on the principle of capacitance micrometry with 0.1nm resolution for displacement measurement. Strain was calculated from the measured displacement using FE analysis. The comparison of mechanical properties helps designer of package to choose copper for ensuring reliability of beam lead in early stage of semiconductor development.

• Journal of Environmental Science International
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• v.16 no.6
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• pp.725-733
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• 2007

The contents of five heavy metals such as lead, cadmium, zinc, copper and manganese in soil and vegetables collected from four sites in Busan district with composite sampling method were determined with ICP emission spectrometer. The ranges of their contents in soil were lead, $1.65\sim4.36ppm;$ cadmium, $0.05\sim0.09ppm;$ zinc, $6.33\sim11.09ppm;$ copper, $0.44\sim1.35ppm;$ manganese, $8.40\sim19.39ppm$, respectively. These contents were lower than the Clarke number. The range of heavy metal contents in four vegetables such as lettuce, radish and its roots, spinach and cabbage were lead, $0.09\sim0.48ppm;$ cadmium, $0.01\sim0.08ppm;$ zinc, $1.81\sim14.62ppm;$ copper, $0.14\sim1.87ppm;$ manganese, $0.71\sim14.5$ 5ppm with the order of Zn(7.30 ppm)>Mn(4.35 ppm)>Cu(0.53 ppm)>Pb(0.19 ppm)>Cd(0.04 ppm) in average contents. The average transfer ratio of metals from soil to vegetables was order of Zn(77.8 %)> Cd(37.5 %)>Cu(34.5 %)>Mn(18.6 %)>Pb(6.7 %). In case of the same cultivating soil, the transfer ratio could be expected to the order of spinach$lettuce{\approx}cabbage$

• Journal of Welding and Joining
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• v.30 no.3
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• pp.32-37
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• 2012

Lead frame which has a high thermal conductivity and high mechanical strength is one of core technology for ultra-thin electronics such as LED lead frames, memory devices of semiconductors, smart phone, PDA, tablet PC, notebook PC etc. In this paper, we fabricated a Cu/STS/Cu 3-layered clad metal for lead frame packaging materials and characterized the mechanical properties and thermal conductive properties of the clad metal lead frame material. The clad metal lead frame material has a comparable thermal conductivity to typical copper alloy lead frame materials and has a reinforced mechanical tensile strength by 1.6 times to typical pure copper lead frame materials. The thermal conductivity and mechanical tensile strength of the Cu/STS/Cu clad metal are 284.35 W/m K and $52.78kg/mm^2$, respectively.

• Journal of Environmental Health Sciences
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• v.8 no.1
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• pp.31-43
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• 1982

Seventy-seven Mugil cephalus of spinal deformation, living in Hanam, Nogsan, and Myeongji area, the downstreams of the Nagdong River, were collected in order to determine their forms and the levels of heavy metal contamination between March and October, 1981. The specimens were examined by X-ray and content of cadmium, lead, copper, and zinc by atomic absorption spectrophotometer. The results were summarized as follows: 1. The rate of appearance of deformational fish to the total Mugil cephflus were 4.3% (13 fish), 5.7% (17 fish), relatively high in May and June (dry season). Meanwhile during March and October they were low by 1.0% (3 fish), 2.0% (6 fish). As far as the research areas are concerned, they appeared in larger numbers in downstreams than in upper streams Myeongji (39), Nogsan (25), and Hanam (13). 2. Concerning with fractured parts of vertebraes,86 percent (66 out of 77) had their caudal regions fractured and 72 percent (55) their first to seventh caudal regions fractured. 3. The average levels of cadmium, lead, copper, zinc detected from flesh were 0.26ppm, 2.06ppm, 6.35ppm, 0.85ppm on the other hand, they were 0.22ppm, 1.84ppm, 5.03ppm, 0.93ppm in normal fish. 4. The average levels of cadmium, lead, copper, zinc measured in the bones were 0.39ppm, 2.55ppm, 8.97ppm, 2.73ppm. Meanwhile, from normal fish they were 0.33ppm, 2.25ppm, 7.24ppm, 2.42ppm. 5. Compared with regional heavy metal contamination such as cadium, lead, zinc, Myeongji area had higher contamination content than Nogsan area Nogsan area than Hanam area. 6. Compared with heavy metal contamination level in their tissues, cadmium was highly found in bones Lead and copper were highly detected in viscera. Particularly in skeleton cadmium was 560 times, zinc 160 times in proportion to those in the downstreams of the Nagdong River.