• Journal of Environmental Health Sciences
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• v.16 no.2
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• pp.83-87
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• 1990

This study was carried out to investigate the pollution of heavy metals in soil of seven stations from the upper spot (Yeungchun Dam) of Kumho River to the downstream(Gangchang Bridge). The results obtained were as follows: 1. The content of heavy metals in soil of Kumho River basin was highest at Gangchang Bridge [expresed in $\mu$g/g : Mn(246.0), Cd(1.90), Fe(551.2), Cu(108.2), Zn(86.4), Cr(80.2), respectively]. Whereas, the content of heavy metals expect for Mn, Cu was lowest at Yeungchun Dam [Cd(0.40), Fe(548.0), Zn(30.7), Cr(6.2), respectively] Also, the content of Cr, Zn was increased when the sampling areas are changed from upstream to downstream except for Hayang Bridge, and Hayang Bridge was the diverging point of the heavy metals content. 2. There were relatively correlated between Mn : FE, Cu, Zn, Cr, Fe : Cu, Zn, Cr(0.40 < $\left$\mid${r}\right$\mid$$ < 0.70), and were high correlated between Cd : Mn, Fe, Cu, Zn, Cu : Zn, Zn : Cr(0.70 < $\left$\mid${r}\right$\mid$$ < 0.90). Particularly, there was higest correlated between Cd : Cr, Cu : Cr(0.90< $\left$\mid${r}\right$\mid$$ < 1.0)

• Biotechnology and Bioprocess Engineering:BBE
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• v.2 no.2
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• pp.126-131
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• 1997

The biosorption and desorption of Cr, Cu and Al were carried out using brown marine algae Sargassum fluitans biomass, known as the good biosorbent of heavy metals. The content of alginate bound to light metals could be changed by physical and chemical pretreatment. The maximum uptake of Cr, Cu and Al was independent of the alginate content. The maximum uptaker of Al was two times(mole basis) than those of Cu and Cr. The aluminum-alginate complex was found in the sorption solution of raw and protonated biomass. Most of Cu, Al and light metals sorbed in the biomass were eluted at pH 1.1. However, only 5 to 10% of Cr sorbed was eluted at pH 1.1. The stoiceometric ion exchange between Cu and Ca ion was observed on Cu biosorption with Ca-loaded biomass. A part of Cr ion was bound to biomass as Cr(OH)2+ or Cr(OH)2+. Al was also bound to biomass as multi-valence ion and interfered with the desorbed Ca ion. The behavior of raw S. fluitans in ten consecutive sorption-desorption cycles has been investigated in a packed bed flow-through-column during a continuous removal of copper from a 35 mg/L aqueous solution at pH 5. The eluant used was a 1%(w/v) CaCl2/HC solution at pH 3.

• Journal of the Korean Magnetics Society
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• v.20 no.1
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• pp.8-12
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• 2010

The magnetostriction and stress of multilayer $NiFeCr/(Cu/Co_{90}Fe_{10}){\times}N/NiFeCr$ films were investigated. As the number of Cu $15{\AA}$/CoFe $15{\AA}$ bilayers was increased, the saturation magnetostriction decreased from $-5.6\times10^{-6}$ at 2 bilayers to $-8.5\times10^{-6}$ at 20 bilayers. A change of CoFe thickness from 10 to $20{\AA}$ caused a decrease in the magnitude of tensile stress from 980MPa to 590MPa as the number of Cu $15{\AA}$/CoFe $15{\AA}$ bilayers increased from 2 to 20. The maximum magnetostrictive anisotropy field that could be developed due to nonzero magnetostriction and stress is calculated to be 135.7 Oe when the number of Cu $15{\AA}$/CoFe $15{\AA}$ bilayers is 10.

• Proceedings of the KAIS Fall Conference
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• 2000.10a
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• pp.34-35
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• 2000

용접기의 전극에 사용되는 크롬동합금은 일반적으로 높은 전기전도도와 고온강도가 요구되어진다. 크롬동합금은 대표적인 시효경화합금으로 용체화처리와 시효처리를 통하여 최적의 성질들이 얻어진다. 본 연구에서는 Cu-0.6wt%Cr, Cu-1.2wt%Cr 합금을 이용하여 용체화처리온도, 시효처리온도 및 시간 등을 변화시켜 실험하였다. 각 열처리에 따른 전기전도도와 경도를 측정하고 미세구조를 조사하여 최적의 공정조건을 구하였다. Cr이 적은 Cu-0.6wt%Cr 합금이 경도의 큰 감소없이 더 높은 전기전도도를 나타내었다.

• Proceedings of the Korean Magnestics Society Conference
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• 1996.05a
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• pp.48-49
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• 1996

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.05a
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• pp.35-35
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• 1994

• Journal of Welding and Joining
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• v.19 no.5
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• pp.534-539
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• 2001

The formation mechanism of microconstituents in brazed joints of duplex stainless steel and Cr-Cu alloy which is an essential process of rocket engine manufacturing was investigated using Cu base insert metal. $SUS329J_3L$ and C18200 were used for base metal and AMS 4764 was used for insert metal. The brazing was carried out under various conditions. There were various phases in the joints, because of reaction between liquid insert metal and base metals. Since liquid insert metal reacts with duplex stainless steel, liquid Cu from insert metal infiltrated into the $\alpha/\beta$ interface of duplex stainless steel. Through the process of Cu infiltration, isolated stainless steel pieces come into the liquid insert metal. Since liquid insert metal reacts with Cr-Cu alloy. Cr precipitates from C18200 come into the liquid insert metal. With increment of bonding temperature and holding time, amounts and sizes of phases increased. but Cr-Mn compounds decreased at 1303k for 1.2ks and Mn-rich phases disappeared Fe-Cr compounds formed.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1643-1645
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• 2000

The effects of pre-sintering and infiltration conditions on the electrical and physical properties of Cu-Cr contact material have been studied. Specimens were prepared by infiltration technique, aiming at the final composition of Cu50w%Cr, with varying pre-sintering and infiltration conditions. It showed that increased pre-sintering temperature had a little influence on the final microstructure of Cu-Cr contact material, but improved the surface morphology of Cr-skeleton resulting in better wettability in the followed infiltration process. It also showed that Cr grain growth and gram shape change became prominent with increasing infiltration temperature and time.

• Journal of Korea Soil Environment Society
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• v.3 no.1
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• pp.45-54
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• 1998

The riverbed structures and heavy metal concentrations of the sediments in the Naktong River, Western Naktong River, and Suyoung Stream were investigated, and then the correlationships between heavy metals were examined. Naktong River was the deepest among the three streams. The deepest and the shallowest sites were site 11(11.58m) and 9(3.35m) in Naktong River, site 7(6.25m) and 4(2.06m) in Western Naktong River, add site 8(2.89m) and 1(0.61m) in Suyoung Stream, respectively. The mean concentration of Cd(45.79ppm) was higher in the sediment of Western Naktong River than in other two streams and those of Pb(76.25ppm), Cr(48.13ppm), and Cu(77.50ppm) were higher in the sediment of Suyovng Stream than in other two streams. The analytical results for correlationships between heavy metals showed that Cu was highly correlated with Cr and Pb was very highly correlated with Cr and Cu in Naktong River. Cu was relatively highly correlated with Cd and Cr and Cr was highly correlated with Pb in Western Naktong River Cd was relatively higlky correlated with Pb and Cu and Cr and Cd, Pb, Cu and Pb, Cr were highly correlated in Suyoung Stream.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.6
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• pp.446-452
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• 2000

This study was carried out to investigate the effect of mine activity on paddy fields, agricultural water, and plants in the ruined Oksung Cu-Zn mine area. Soil samples collected from paddy fields adjacent to the Cu-Zn mine sites were sequentially extracted and determined the contents of heavy metals such as Cd, Zn, Cu, Pb, Cr and Ni. Distribution of exchangeable heavy metals in soils was 30.2% of Cd, 11.3% of Zn, 2.2% of Cu, 4.6% of Cr, 0.6% of Pb and 3.9% of Ni. Water soluble heavy metals were only detected with Zn. The contents of heavy metals in water collected from the mine were 0.01 of Cd, 27.35 of Zn, 4.86 of Cu, 1.04 of Pb, 0.03 of Cr and $0.08mg\;L^{-1}$ of Ni. while the contents in waler collected out of the mine were 16.67 of Zn, 0.59 of Cu, 0.49 of Pb, 0.05 of Cr and $0.06mg\;L^{-1}$ of Ni. On the other hand, agricultural water near mine area were 1.26 of Zn, 0.05 of Cu, 0.05 of Pb and $0.02mg\;L^{-1}$ of Ni. Both Cd and Cr were not detected in the agricultural water.