• Journal of the Korean Society for Heat Treatment
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• v.20 no.5
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• pp.243-249
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• 2007

The age hardening behavior and mechanical properties of an extruded Al-Zn-Mg-(Cu)-0.1 wt.%Sc alloy were investigated with the Sc addition and ageing temperature. The results showed that the $Al_3Sc$ compounds were formed by Sc addition and distributed preferentially along the extrusion direction. The age hardening of Al-Zn-Mg-Cu-0.1 wt.%Sc alloy which was treated by T6 process was more significant than that of Al-Zn-Mg-0.1 wt.%Sc alloy. The tensile property of Al-Zn-Mg-Cu+0.1 wt.%Sc alloy was also higher than that of Al-Zn-Mg-0.1 wt.%Sc alloy, which is 691 MPa and 584 MPa in strength and 9% and 11% in elongation, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.22-25
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• 2000

ZnS:Cu,Cl 형광체의 여기 및 발광 스펙트럼 측정 결과 주게인 $Cl^-$ 이온과 받게인 $Cu^+$ 이온 사이의 흡수와 발광에 기인하는 peak과 국소화된 발광 중심인 $(CU_2)^{2+}$ 이온의 흡수와 발광에 기인하는 peak이 관측되었다. CuCl의 첨가량이 증가함에 따라 $Cu^+$ 이온의 농도가 증가하게 되어 $(Cu_2)^{2+}$ 이온에 기안하는 발광으로부터 공명 에너지 전달 (Resonant Energy Transfer)의 확률이 높아지기 때문에 513 nm를 중심으로 하는 발광의 세기가 증가하게 된다. 자체 제작한 ZnS:Cu,Cl 형광체를 이용하여 제작한 소자의 휘도 측정결과 400 Hz, 100 V 에서 CuCl 의 첨가량이 0.2 mole% 일 때 휘도가 최대였고, 진동수가 증가함에 따라 휘도가 포화되는 현상이 나타났다. CuCl의 첨가량이 증가함에 따라 513 nm를 중심으로 하는 발광이 강해지고 CIE 좌표값이 녹색영역으로 이동하게 된다. 진동수가 증가하면 인가된 전압의 유지 시간이 짧아지게 되어 발광의 감쇄시간이 긴 513 nm를 중심으로 하는 발광보다 감쇄시간이 짧은 458 nm를 중심으로 하는 발광이 강해지게 되고, CIE 좌표값이 청색영역으로 이동하게 된다.

• Korean Journal of Materials Research
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• v.13 no.8
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• pp.503-508
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• 2003

The purpose of this study is to investigate the effect of $V_2$$O_{5}$ addition on the Ag and Cu precipitation in the NiCuZn ferrite layers of 7.7${\times}$4.5${\times}$1.0 mm sized multi-layer chip inductors prepared by the screen printing method using 0∼0.5 wt% $V_2$$O_{5}$ -doped ferrite pastes. With increasing the $V_2$$O_{5}$ content and sintering temperature, Ag and Cu oxide coprecipitated more and more at the polished surface of ferrite layers during re-annealing at $840^{\circ}C$. It was thought that during the sintering process, V dissolved in the NiCuZn ferrite lattice and the Ag-Cu liquid phase of low melting point was formed in the ferrite layers due to the Cu segregation from the ferrite lattice and Ag diffusion from the internal electrode. During re-annealing at $840^{\circ}C$, the Ag-Cu liquid phase came out the polished surface of ferrite layers, and was decomposed into the isolated Ag particles and the Cu oxide phase during the cooling process.

• Applied Microscopy
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• v.27 no.3
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• pp.235-241
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• 1997

The microstructure of intermixed $Zn_{1-x}Fe_xSe$ layers in the (ZnSe/FeSe) superstrates grown on (00l) GaAs substrates has been investigated by high -resolution transmission electron microscopy and computer simulations of lattice images. Computer image simulations have been performed by the multislice method under various sample thicknesses and defocusing conditions. The simulated lattice images were compared with the experimental lattice images. Also, CuAu-I type ordering was often observed in the intermixed $Zn_{1-x}Fe_xSe$ alloys. This CuAu-I type ordered structure consists of alternating ZnSe and FeSe monolayers along the <100> and <110> directions.

• 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)

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1488-1490
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• 2000

ZnO:Cu thin films are deposited by using an RF magnetron co-sputtering system with Cu chips attached on ZnO target. Structural and electrical properties are analyzed as a function of deposition conditions, such as Cu chip areas, $O_2/(Ar+O_2)$ ratios, and working pressures, The results show that a higher electrical resistivity above $10^{10}$ ${\Omega}cm$ along with an excellent c-axial growth can be easily achieved by Cu-doping. SAW filters based on the ZnO:Cu films are also fabricated to estimate the electric-mechanical coupling coefficient($K^{2}_{eff}$). Higher $K^{2}_{eff}$ and lower insertion losses are observed for ZnO:Cu films, compared with those for ZnO films.

• Advances in materials Research
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• v.13 no.1
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• pp.55-62
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• 2024

Cu-based sulfides have recently emerged as promising thermoelectric (TE) materials due to their low cost, non-toxicity, and abundance. In this research, point defect structure of Cu_2-xZnSnS₄ (x=0.1, 0.2, 0.3) samples were synthesized by the mechanical alloying method. Mixed powders of Cu, Zn, Sn and S were milled using high energy ball milling at a rotation speed of 300 rpm in Ar atmosphere. The milled Cu_2-xZnSnS₄ powders were heat-treated at 723 K for 24 h, and subsequently consolidated using spark plasma sintering (SPS) under an applied pressure of 60 MPa for 15 min. The thermal conductivity of the sintered Cu_2-xZnSnS₄ samples was evaluated. A well-defined Cu_2-xZnSnS₄ powders were successfully formed after milling for 16 h, with the particle sizes mostly distributed in the range of 60-100 nm. The lattice constants of aand cdecreased with increasing composition value x. The thermal conductivity of sintered x=0.1 sample exhibited the lowest value and attained 0.93 W/m K at 673 K.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.3
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• pp.183-191
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• 1991

A study was conducted to determine the influence of soil chemical properties on the distribution and forms of cadmium (Cd), lead (Pb), copper(Cu) and Zinc(Zn) in paddy soils near zinc mines. A sequential extraction procedure was used to fractionate the heavy metals in soils into the designated from of water soluble, exchangeable, organically bound, oxide/carbonate, and sulfide/residual. The predominant form of Cd, Pb, Cu and Zn in the soils was found to be sulfide/residual form. Oxide/carbonate Cd and Pb and organically bound Cu were high, while exchangeable Pb and Cu were very low. Water soluble Cd, Pb and Cu were not detected in the soils. The percentages of the heavy metals content in exchangeable fractions were inversely correlated with those in sulfide/residual fractions in the soils. Exchangeable Cd and Zn and the oxide/carbonate Pb were shifting to the sulfide/residual form with soil depth and the chemical forms of Cu were not changed. Organically bound Cu was positively correlated with soil organic matter content but Cd, Pb and Zn were not. The percentages of Cd, Pb and Zn content in exchangeable forms decreased with soil pH, while those in oxide/carbonate and sulfide/residual forms increased with soil pH. The amounts of oxide/carbonate and sulfide/residual forms of pb were higher than those of Cd and Zn at same soil pH.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.4
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• pp.249-252
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• 1993

Water culture studies were conducted in the greenhouse with mulberry plants to investigate the nutrient uptake, especially Zn and Cu, under high phosphrous concentration. Mulberry plants were grown with five phosphorus levels(0, 0.2, 0.5, 2.0, 5.0 mM). Leaves and roots were analyzed for water content, total nitrogen, P, K, Ca, Mg, Fe, Mn, total Zn, soluble Zn, Cu, Cl, $NO_3HPO_4$ and $SO_4$. Dry matter increased upto 2.0mM phosphorus level, and then decreased. Water content, total nitrogen, P, K, and Fe in leaves increased with increasing phosphorus level. Total Zn content in leaves showed little change, whereas soluble Zn increased and Cu decreased with increasing phosphorus level. With increasing phosphous level. $SO_4$ and Cl decreased and then sharply increased above 2.0mM phosphorus. Lower uptake of Cu and higher uptake of $SO_4$ and Cl suggest a cause of mulberry yield decline with high accumulation of soil phosphorus.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.11
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• pp.1616-1620
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• 2001

Two feeding trials were conducted to study the effects of different chelated copper and zinc compounds on the performance and fecal excretions of weanling pigs. In Exp. 1, 150 weanling pigs ($L{\times}Y{\times}D$, $12.30{\pm}2.07kg$) were randomly assigned to five dietary treatments: 170 ppm Cu from $CuSO_4$, 85 ppm Cu from Cu amino-chelate (CAC), 170 ppm Cu from CAC, 85 ppm Cu from Cu-Lysine (CL), and 170 ppm Cu from CL. In Exp. 2, 150 weanling pigs ($L{\times}Y{\times}D$, $12.52{\pm}1.80kg$) were randomly assigned to five dietary treatments: 120 ppm Zn from $ZnSO_4$, 60 ppm Zn from Zn-amino-chelate (ZAC), 120 ppm Zn from ZAC, 60 ppm Zn from Zn-Methionine (ZM), and 120 ppm Zn from ZM. In both experiments, pigs were randomly distributed to the treatments following a randomized complete block design on the basis of body weight as the blocking variable. Each experiment was conducted for 28 days. Blood and fecal samples were collected to determine mineral contents as affected by the dietary treatments. There was no difference (p>0.05) in ADG and ADFI among treatments, but F/G was improved (p<0.05) in pigs fed diet with 170 ppm CAC than 85 ppm CL but not different (p>0.05) to the control (170 ppm $CuSO_4$). Regardless of copper source, concentration of Cu in serum and feces were higher in pigs fed diet with 170 ppm Cu than pigs fed diet with 85 ppm Cu (Exp 1). In Exp 2 the ADG was higher (p<0.05) in pigs fed diet with 120 ppm ZM than in pigs fed diets with 120 ppm $ZnSO_4$ and 60 ppm ZAC and ZM. The serum zinc concentration was generally higher (p<0.05) in pigs fed diet with organic source than the control group ($ZnSO_4$). Also, there was a trend towards a decrease in fecal excretions of zinc when dietary zinc level was low. The efficacy of the two chelated copper and zinc sources is similar in terms of growth performance. The fecal excretions for Cu and Zn could be reduced in pigs fed low level of these minerals using organic sources.