• The Journal of Engineering Geology
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• v.33 no.1
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• pp.39-49
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• 2023

Soil contaminants measured and managed in Korea include those of geologic origin such as arsenic, cadmium, copper, lead, zinc, nickel, mercury, and fluoride. This study identifies the distribution of these contaminants using GIS modeling to analyze the spatial probability of soil contamination originating from geology. The modeling found that cadmium, copper, lead, nickel, and mercury often exceed the regulated standard by <1%. Concentrations of arsenic and zinc greatly exceeded the standard in the vicinity of mines and industrial complexes: mining and industry seemed to have substantial effects on the concentrations of these metals. Although fluoride was sampled at the lowest number of points, its frequency of exceeding the standard was the highest. No obvious source of artificial contamination has been identified, and fluoride's distribution characteristics showed continuity over a wide area, suggesting a strong correlation between geological characteristics and fluoride concentration. The highest frequencies of fluoride exceeding the standard were in Jurassic granite (40.00%) and Precambrian banded gneiss (34.12%). As these rocks contributed to the formation of soil through their weathering, high fluoride concentrations can be expected in soil in areas where these rocks are distributed.

• Economic and Environmental Geology
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• v.40 no.3 s.184
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• pp.277-293
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• 2007

Seasonal and spatial variations in the concentrations of trace elements, pH and Eh were found in a creek watershed affected by mine drainage and leachate from several waste rock dumps within the As-Pb-rich Indae mine site. Because of mining activity dating back to about 40 years ago and rupture of the waste rock dumps, this creek was heavily contaminated. Due to the influx of leachate and mine drainage, the water quality of upstream reach in this creek was characterized by largest seasonal and spatial variations in concentrations of Zn(up to $5.830 mg/{\ell}$), Cu(up to $1.333 mg/{\ell}$), Cd(up to $0.031 mg/{\ell}$) and $SO_4^{2-}$(up to $173 mg/{\ell}$), relatively acidic pH values (3.8-5.1) and highly oxidized condition. The most abundant metals in the leachate samples were in order of Zn($0.045-13.909 mg/{\ell}$), Fe($0.017-8.730mg/{\ell}$), Cu($0.010-4.154mg/{\ell}$) and Cd($n.d.-0.077mg/{\ell}$), with low pH(3.1-6.1), and high $SO_4^{2-}$(up to $310 mg/{\ell}$). The mine drainage also contained high concentrations of Zn, Cu, Cd and $SO_4^{2-}$ and remained constantly near-neutral pH values(6.5-7.0) in all the year. While the leachate and mine drainage might not affect short-term fluctuations in flow, it may significantly influence the concentrations of chemicals in the stream. The abundance and chemistry of Fe-(oxy)hydroxide within this creek indicated that the Fe-(oxy)hydroxide formation could be responsible for some removal of trace elements from the creek waters. Spatial and seasonal variations along down-stream reach of this creek were caused largely by the influx of water from uncontaminated tributaries. In addition, the trace metal concentrations in this creek have been decreased nearly down to the background level at a short distance from the discharge points without any artificial treatments after hydrologic mixing in a tributary. The nonconservative(i.e. precipitation, adsorption, oxidation, dissolution etc.) and conservative(hydrologic mixing) reactions constituted an efficient mechanism of natural attenuation which reduces considerably the transference of trace elements to rivers.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.4
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• pp.333-339
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• 2008

Densification behavior of copper powder was investigated to study the effect of an aluminum mold under warm pressing. The low flow stress of an aluminum mold is appropriate to apply hydrostatic stress to powder compacts during compaction under high temperature. The suggested powder metallurgy process is very useful under high temperature since copper powder compacts have higher relative density over axial stress of 100 MPa and show more homogeneity as compared with conventional warm pressing. Elastoplastic constitutive equation proposed by Shima and Oyane was implemented into a finite element program (ABAQUS) for densification behavior under warn pressing by using a metal mold. Finite element results agreed well with experimental data for densification and deformation of copper powder compacts in the mold.

• Proceedings of the KIEE Conference
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• 2001.11a
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• pp.9-11
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• 2001

차세대 고속 DRAM기술에 사용될 금속인 Cu의 확산 방지막(diffusion harrier) 물질로는 Ta 또는 W 같은 Refractory metal 이 융점(melting point)이 높고 저항값이 낮아 많이 연구 보고되고 있으나, 본 논문에서는 초고주파 소자에서 Au의 확산 방지 막으로 많이 사용되고 있으며. 선택적 증착이 용이한 Pt과 Ni를 MOS 소자의 Cu 확산 방지 막으로 적용하며 어닐링한 후 소자의 게이트 산화막 누설전류($I_{leak}$), 그리고. Si/$SiO_2$ 계면의 trap density 등의 변이를 측정하여 Cu가 소자의 특성 열화에 미치는 영향을 연구하였다. 실험 결과 Pt/Ti($200{\AA}/100{\AA}$)를 적용한 경우 소자 측성 열화가 가장 적었으며. 이는 Copper의 확산 방지막으로 Pt/Ti를 사용하여 전기적 특성 및 계면 특성을 개선시킬 수 있음을 보여 주었다. 이는 SIMS Profile을 통해서도 확인하였다.

• Corrosion Science and Technology
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• v.12 no.5
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• pp.253-258
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• 2013

Effects of copper hydroxide(II) on the curing and the corrosion resistance of electrocoating were investigated by MEK rubbing test, electrochemical impedance spectroscopy (EIS) and Thermo-gravimetric analysis (TGA). Curing performance of electrocoating was lowered with increasing the content of copper hydroxide(II) as evidenced by the MEK rub performance which decreased with increasing the content of copper hydroxide(II). This indicates copper hydroxide(II) affected the blocked isocyanate reaction in the coatings, by the decomposition of copper hydroxide(II) to CuO and $H_2O$ during reaction of isocyanate with nuclephiles. Corrosion resistance of coatings also decreased with the content of copper hydroxide. This reflects the higher barrier property in coatings with higher curing performance.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2000.05a
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• pp.195-200
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• 2000

Chitin과 탈아세틸화된 chitosan은 중금속 제거에 효과적인 생물흡착제로 잘 알려져 있다. 그러나 본 연구의 결과 crab shell에 있어서의 중금속 제거효율이 순수 chitin과 chitosan에서 보다 더 뛰어남을 알 수가 있었다. 납, 카드뮴, 망간이온 제거실험에서 crab shell은 초기 2시간 이내에 모두 제거되었으나, chitin과 chitosan의 흡착 실험에선 14시간이 경과되어도 이들 중금속의 대부분 수용액 내에서 거의 제거되지 않았다. 구리의 경우 염의 형태에 따른 흡착의 영향을 chitosan에선 제거된 량이 Cu($SO_{4})_{2}$ > Cu($NO_{3})_{2}$ > Cu($Cl_{2}$)의 순으로 나타났으나 chitin에선 모두 흡착이 거의 안된 상태로 나타났다. 주사현미경 분석 결과 crab shell의 표면에 납이 축적되어 있는 상태를 확인하였다.

• Journal of the Korean Society of Safety
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• v.8 no.3
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• pp.56-63
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• 1993

In this study the ultrasound which has the properties of mixing, surface cleaning effect, increasing of the effective reaction surface area and increasing of the effective collision frequency, was used to enhance the recovering efficiency of Cu from the Cu-ion containning waste water. The ultrasonic reactor used in this study was dsigned and constructed for improving the disadvantage of the existing ultrasonic reactor From the experimental result and its analysis. we obtained following conclusions. 1. The ultrasound increased the rate of electrochemical deposition to 582.2% in maximum at the Condition of 0.1M-CuSO$_4$and 2.1V-overpotential. 2. This study gave the possibility of the scale-up of ultrasonic reactor and In particular, ultrasonic reactor would be effective in treatment of waste water contains a low concentration of Cu ion.

• Journal of Powder Materials
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• v.16 no.2
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• pp.131-137
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• 2009

This paper deals with the effects of the surfactant and preplate process (sensitization and activation) on electroless copper plating on carbon nano-fiber (CNF). Ultrasonic irradiation was applied both during dispersion of CNF and during electroless plating containing preplate process. The dispersion of CNF and flatness of the plated copper film were discussed based on the changes in surfactant concentration and preplate process time. It was clearly shown that high concentration of surfactant and long time of preplate process could promote the agglomeration of CNF and uneven copper plating on CNF.

• Solar Energy
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• v.10 no.1
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• pp.57-62
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• 1990

The influence of substrate materials on the thermal stability of black chrome coating was investigated by Rutherford backscattering spectrometry(RBS). In order to study thermal degradation the sample were annealed in air for 24 hour at temperature of 450. Cu, Ni, and S.S(Stainless steel 304) were used as substrate for selective coating. The experimental results of substrate diffusion was discussed. It was found that little diffusion of substrate material occurred for the sample pre. pared on stainless steel.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1069-1071
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• 1999

Closing switch는 여러 가지가 있으나, 방전시 발생하는 Z-pinch로 인한 전극의 손상으로 수명이 짧고, 소음, 열 발생 등으로 소형화가 문제점으로 되어왔다. Inverse pinch현상을 이용하여 기존의 closing switch보다 전류밀도가 1/62, 주울열의 발생, 인덕턴스가 작다. INPIStron의 수명에 영향을 미치는 절연물질은 세라믹을, 도전체로서는 경제성을 감안하여 쉽게 구할 수 있는 구리를 이용하여 제작하였고, 트리거는 gas-puffing방식을 사용하였다. 또한 이렇게 제작된 INPIStron을 이용하여 2MJ-500kA급 pulsed power 전원 장치를 개발하였다.