• 한국재료학회지
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• 제33권5호
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• pp.214-221
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• 2023

As a filler metal for lowering the melting point of Ag, many alloy metal candidates have emerged, such as cadmium, with zinc, manganese, nickel, and titanium as active metals. However, since cadmium is known to be harmful to the human body, Cd-free filler metals are now mainly used. Still, no study has been conducted comparing the characteristics of joints prepared with and without cadmium. In addition, studies have yet to be conducted comparing the typical characteristics of brazing filler metals with special structures, and the joint characteristics of brazing filler metals with available frames. In this study, the characteristics of junctions of silver-based intercalation metals were compared based on the type of filler metal additives, using a special structure, a filler metal sandwich structure, to protect the internal base metal. The general filler metal was compared using the structure, and the thickness of the filler metal according to the thickness was reached. A comparison of the characteristics of the junction was conducted to identify the characteristics of an intersection of silver-based brazing filler metal and the effect on joint strength. Each filler metal's collective tensile strength was measured, and the relationship between joint characteristics and tensile joint strength was explored. The junction was estimated through micro strength measurement, contact angle measurement with the base metal when the filler metal was melted, XRD image observation, composition analysis for each phase through SEM-EDS, and microstructure phase acquisition.

• Environmental Analysis Health and Toxicology
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• 제11권3_4호
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• pp.23-32
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• 1996

In this study, we investgated the uptake capacity of several water plants for heavy metals (lead and cadmium) in soil of rivers where are adjacent to a industrial complex in Chun-An city and in A-San city. We also examined the deposition pattern of heavy metal in plants. The results are as follows: 1. The soil of river in Chun-An city was polluted more serious than that of A-San city. In Chun-An city, mean values of lead and cadmium contents in soil were 26.224 $\pm$ 28.037 $\mu$g/g, and 0.854 $\pm$ 1. 127 $\mu$g/g, respectively. 2. Water plants examined in this study were Slum suave KITAGAWA, Persicaria thunbergii H. GROSS, Phragmiles japonica STEUD, Echinochloa crus-galli var. frumentacea WIGHT and Persicaria hydropiper SPACH. Both metal contents of several water plants distributed in Chun-An city were higher than those in A-San city. In these plants, Slum suave showed the highest uptake capacity for lead and cadmium. The mean values of lead and cadmium contents in Slum suave were 40.957 $\pm$ 29.577 $\mu$g/g and 1. 930 $\pm$ 1. 076 $\mu$g/g, respectively. Persicaria thunbergii also showed a relatively high uptake capacity for both metal. 3. Correlation between metal contents in soil and water plants was high. In both cases of Sium suave and Persicaria thunbergii correlation coefficients were 0.605 and 0.549, respectively. 4. We analyzed lead and cadmium contents in root, stem and leaf of several water plants. Both metals were mostly deposited in root. Much of both metals were also deposited in leaf. From the results, we suggest that Slum suave KITAGAWA and Persicaria thunbegii H. GROSS can be used to reduce heavy metals from industrial waste water.

• The Korean Journal of Ecology
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• 제23권1호
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• pp.59-64
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• 2000

진해만의 중금속 오염도를 평가하기 위해 해저퇴적물, 해수 및 참굴의 중금속 농도를 측정하였다. 해저퇴적물내 카드뮴, 코발트, 구리, 니켈, 납, 아연의 농도범위는 0.1∼2.4, 12.6∼14.4, 25.3∼92.3, 32. 4∼93.5, 24.1∼81.2, 124∼477 ㎍/g 으로 나타났다. 인간의 산업활동과 관련된 카드뮴, 구리, 납, 아연의 농도는 마산 내만에서 높게 나타났다. 해수내의 용존성 카드뮴, 코발트, 구리, 니켈, 납, 아연의 농도범위는 ＜0.010∼0.043, 0.008∼0.120,0.31∼0.90,0.25∼3.10, 0.010∼0.142,0.27∼9.04 ㎍/L로 나타났다. 해수의 카드뮴, 구리, 납, 아연의 농도도 퇴적물에서처럼 마산 내만에서 높게 나타났으므로 마산만이 진해만의 주오염원임을 알 수 있었다. 참굴의 아연, 구리, 카드뮴, 납, 코발트, 니켈 둥의 생물농축계수(BCF)는 647373, 280861, 145069, 44559, 13524, 2745 순으로 나타났으며, 다른 이매패류에 비해 강한 중금속 축적종으로 나타났다.

• 한국환경보건학회지
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• 제23권2호
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• pp.98-105
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• 1997

The study on the cytotoxicity of heavy metals was carried out to evaluate the cytotoxic effect of those on mouse L929 fibroblast cell in 96-well microtiter plates. The cytotoxicity was assayed by the neutral red, tetrazolium MTT, total protein, micronuclei test. The cytotoxicity of the heavy metals by neutral red and tetrazolium MTT was showed in order, cadmium > zinc > nickel for the cationic metals tested. The effect of metal-metal interaction on the cytotoxicity showed a marked reduction of cadmium toxicity by zinc, to a lesser degree, by nickel. The amount of total protein in treated group added heavy metals was less than that of the control and treated cadmium alone was less than those of combination with nickel or zinc. At midpoint cytotoxicity values of heavy metals, the frequency of micronuclei on the cell treated heavy metals was more than that of control and treated cadmium alone was more than those of combination with nickel or zinc. From those results, it could be suggested that the heavy metals decreased the viability of mouse fibroblast L929 cells in a concentration-dependent manner and have cytogenic toxic effects, but mixed group decreased the cytotoxic and cytogenic toxicity on L929 cells.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 학술논문집
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• pp.337-337
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• 2004

As one of researches for the P ＆ T purposes, a basic experiment on the recovery of actinide elements from the mixture with rare earth elements by means of electrorefining using a liquid cadmium cathode in the LiCl-KC1 eutectic melt was carried out. In order to examine the behaviors of electrodeposition of metal ions on a liquid electrode, recovery experiments of rare earth metals resulting from forming electrodeposits were performed by a galvanostatic electrolysis method at various current densities. A cyclic voltammetric technique was applied to determine reduction-oxidation potential of each metal element in the melt and to detect the changes of the multi component melt composition for on-line monitoring. Also, a collaboration study with RIAR was completed to test the preliminary feasibility on a recovery of actinide elements from the mixture with rare earth elements using a liquid cadmium cathode and actinide metals. Experimental results showed that the ratio of actinides to rare earths, 9: 0.5∼1 led to the rare earth content of about 5∼10 wt% in the deposit.

• 약학회지
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• 제40권5호
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• pp.501-506
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• 1996

This study was conducted to investigate on the changes of copper and zinc concentration in rat's tissues and urine after cadmium administration with atomic absorption spectroph otometric method. It is found that cadmium appeared to cause a change in the behavior of copper and zinc in vivo system even during 1 month after cadmium treatment.

• 한국환경보건학회지
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• 제12권1호
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• pp.47-54
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• 1986

The purpose of the study is to determine the effects of sodium alginate on the suppression of organ accumulation of heavy metals were tested by mice. The seventy mice were divided into the control group and the experimental groups. The mice of cadmium group were subdivided into three groups by dose of 10 ppm cadmium group, adding 1% sodium alginate to the diets contaminated with 10 ppm cadmium group and adding 10% sodium alginate to the diets contaminated with 10 ppm cadmium group. The mice of copper group were subdivided into three groups by dose of 10 ppm copper group, adding 1% sodium alginate to the diets contaminated with 10 ppm copper group, and adding 10% sodium alginate to the diets contaminated with 10 ppm copper group. After the series of feeding of twenty-one days, the mice were killed and examined. Organs and feces were removed and analyzed for cadmium and copper amounts. The results obtained were as follows 1. As for average body weight gains, those of control group mice were the highest than heavy metal group and those of adding 10% sodium alginate to the diets contaminated with 10 ppm copper group the lowest. 2. The amount of cadmium accumulated in liver and kidney was higher than blood. The amount of cadmium in organs was higher in cadmium group than adding sodium alginate to the diets contaminated with cadmium group. 3. The amount of copper in liver was the highest, and that of copper in blood was the lowest. 4. The excretion of heavy metals was promotioned by adding 10% sodium alginate to the diets contaminated with 10 ppm heavy metal. ( P < 0.05 ).

• 농촌의학ㆍ지역보건
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• 제18권2호
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• pp.153-160
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• 1993

Health complaints among vinylhouse workers in Sungjoo county, Kyungpook province led to the investigation of heavy metal levels of air, soil and humans as well as physical conditions of the vinylhouse. The average temperature and humidity inside the vinylhouse were 8 higher and 10% point lower, respectively, as compared to the outside. While discomfort index(D. I.) outside was pleasant level(69.2), D. I. inside was 82 at which point 100% of people feels discomfort. Cadmium concentration of soils inside the vinylhouse(0.116 mg/kg) was 1.8 times higher than the soils outside. Arsenic concentration of soils inside the vinylhouse(4.882 mg/kg) was only slightly higher than the soils outside(4.182 ng/kg). However, both heavy metal concentrations detected in soils inside or outside the vinylhouse were within the normal range. Analysis of 10 air samples taken inside the vinylhouse showed that only one sample had a cadmium concentration above the detectable level and the rest of samples were below the detectable levels. While there were no difference of arsenic concentrations in urine between male and female, cadmium concentrations in urine samples of female (3.31 ug/l) was slightly higher than male(2.38 ug/l). Age-dependent increases of cadmium concentrations in urine samples were also observed. However, there was no concentration difference of these heavy metals in urine between vinylhouse workers and non-vinylhouse workers. Urine concentrations of cadmium and arsenic detected from vinylhouse workers or non-vinylhouse workers were within the normal range. The present study represents a first attempt to evaluate physical and environmental risk factors of the vinylhouse affecting the vinylhouse farmer's health. The study revealed that, while physical conditions of the vinylhouse such as temperature and humidity are the possible factors associated with the farmer's complaints, environmental contamination as judged from heavy metal levels in soil, air and humans is not a risk factor contributing to the vinylhouse farmer's health problem.

• 한국환경과학회지
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• 제19권9호
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• pp.1177-1185
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• 2010

To examine the potency of biosorbent, the adsorption capacity of Pseudomonas cepacia H42 isolated from fresh water plant root was compared with Saccharomyces cerevisiae SEY2102 on bases of biomass, concentration of heavy metal, presence of light metals, immobilized cell, and ion exchange resin. P. cepacia H42 biomass of 0.05-0.5 g/L increased adsorption and above 1.0 g/L of yeast biomass was the most effective in adsorption. By applying the same amount of biomass, lead showed the highest adsorption on two strains and the adsorption strength was lead>copper>cadmium on both strains. The high heavy metal concentration induced the high adsorption capacity. P. cepacia H42 adsorption was in the order of copper>lead>cadmium and lead>copper>cadmium by yeast in 10 mg/L. Both strain showed same adsorption strength in the order of lead>copper>cadmium in 100 mg/L and 1000 mg/L. The adsorption capacity of both yeast and P. cepacia H42 was decreased in the presence of light metals and the order of cadmium>copper>lead. $Mg^{2+}$ induced the least adsorption while $Na^+$ induced highest adsorption. The adsorption capacity of immobilized yeast and P. cepacia H42 was detected between 200-400 mL in flow volume and decreased in the presence of light metals. Ion exchange containing light metals caused 30-50% adsorption reduction on both strains.

• 미생물학회지
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• 제38권1호
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• pp.26-30
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• 2002

담수식물 수초의 근계 에 부착하는 미생물의 자정력을 탐색하기 위하여 분리된 세균인 Pseudomonas cepacia KH410 을 대상으로 중금속인 납과 구리, 카드뮴이온에 대한 영향을 조사하였다. 이 균의 최적 배지로 Nutrient기본배지를 사용하였고 최대 균체 생산을 위하여 yeast extract, soytone을 각각 1%씩 첨가하였고, NaCl은 0.5%, 초기 pH는 7.0 그리고 배양은 $28^{\circ}C$에서 24 시간 진탕 배양하였다. 이러한 배양 조건하에서 얻어진 최대 균체는 2.72 g DCW/ι-medium이었다. 각각의 100 mg/ι중금속 첨가에 따른 균체 생산은 납은 1.98 g/ι, 구리는 1.58g/ι, 카드뮴은 0.2 g/ι로 세가지 중금속 첨가에 따른 균체 생산이 낮아졌으며 중금속별로 균체 생산량에 차이를 나타내었다. 균의 생육에 영향을 미치는 각각의 중금속 농도를 비교하여 본 결과 최저생육저지농도 (MIC)가 납은 1.3 mM, 구리는 0.8 mM, 카드윰은 0.4 mM로써 카드윰이 균체에 미치는 영향이 가장 높게 나타났다. 동일 농도인 100 mg/ι용액 내에서의 세가지 중금속에 대한 균체의 변화는 균체끼리의 응집 현상이 광학현미경하에서 1 일에서 4 일 사이에 관찰되었고 전자현미경하에서는 각각의 중금속을 10분 노출시킨 후부터 세포벽 쪽으로 이온들이 이동되는 것이 관찰되었고 2 시간 후에는 세포외피, 원형질분리 및 세포내부로 침적된 양상이 각각 다르게 나타났으며 균체의 손상은 카드뮴이 가장 높았고 그 정도는 카드뮴>구리>납의 순이었다.