• Journal of Korea Soil Environment Society
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• v.1 no.2
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• pp.23-34
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• 1996

The biological magnification of Pb, Cu, Zn and Fe in vascular plant, Persicaria thunbergii, Trapa japonica and Nymphoides peltata natually grown at the river and riverside and relationship between the concentration of heavy metals in these vascular plants and in the soil were investigated in the Chonju river, Chonju city. The biological magnification values of these metals in P thunbergii were founded as follows ; Pb, Cu, Zn and Fe were 80.4~254.6$mu\textrm{g}$/g, 284.6~688.4$mu\textrm{g}$/g, 635.5~1979.4$mu\textrm{g}$/g and 1160.0~3590.9$mu\textrm{g}$/g respectively. In the case of T. japonica, Pb, Cu, Zn and Fe were 107.8~306.0$mu\textrm{g}$/g, 282.7~963.0p$mu\textrm{g}$/g, 1328.3~3546.$mu\textrm{g}$/g and 656.8~9944.0$mu\textrm{g}$/g and in N. peltata, 140.1~ 193.9$mu\textrm{g}$/g, 187.7~327.3$mu\textrm{g}$/g, 1126.6~1723.6$mu\textrm{g}$/g and 611.7~1914.6$mu\textrm{g}$/g respectively. The amount of the biological magnification of heavy metals in the leaf, stem and root of these plants was generally increased in the sequence of leaf

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.05a
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• pp.225-231
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• 2006

.고상반응법 (solid state reaction)합성된 ZnS:Mn,Cu,Cl 형광체는 약 $20^{\sim}25{\mu}m$ 의 구형이고, Cubic/hexagonal 구조를 보였다. Electroluminescent device(ELD)는 실크 스크린된 형광층(ZnS:Mn,Cu,Cl)/유전체층 ($BaTiO_3$)으로 구성되었으며, 각층은 $30^{\sim}50{\mu}m,\;50^{\sim}60{\mu}m$ 정도로 도포 하였다. 100 V-400 Hz 의 구동조건에서, ELD 의 백색 발광은 450 nm, 480 nm 픽에서 각각 $Cl_s{\to}Cu^{+}\;_{Zn},\;Cl_s{\to}Cu^{2+}\;_{Zn}$ 전이에 의해 중첩된 청색, 녹색 밴드의 발광과, 580 nm 픽에서 Mn 의 $^{4}T_1{\to}^{6}A_1$ 전이에 의한 황색 밴드의 발광으로 이루어진다. Cu 농도의 증가에 따라 450 nm 의 발광 밴드의 휘도는 감소하며 580 nm 의 발광 밴드의 휘도가 증가하였고 발광 휘도가 향상되었다. 즉, 색온도가 높은 cold white(10000 K)에서 색온도가 낮은 Warm white(3000 K) 로 변한다. 이것은 450 nm 의 발광 밴드가 580 nm 의 발광 밴드에 흡수되는 에너지 전이 (Energy transfer) 현상에 기인한다. ZnS:Mn,Cu,Cl 의 Mn 1.5 wt %, Cu 2.5 wt.% 에서 최적 발광 휘도를 보이며, 100 V-400 Hz 에서 약 $12cd/cm^2$이였다.

• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.141-146
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• 2014

A series of bimetallic Cu-Zn/$SiO_2$ catalysts were prepared via thermal decomposition of the as-synthesized $CuZn(OH)_4(H_2SiO_3)_2{\cdot}nH_2O$ hydroxides precursors. This highly dispersed Cu-solid base catalyst is extremely effective for hydrogenation of ethyl acetate to ethanol. The reduction and oxidation features of the precursors prepared by coprecipitation method and catalysts were extensively investigated by TGA, XRD, TPR and $N_2$-adsorption techniques. Catalytic activity by ethyl acetate hydrogenation of reaction temperatures between 120 and $300^{\circ}C$, different catalyst calcination and reduction temperatures, different Cu/Zn loadings have been examined extensively. The relation between the performance for hydrogenation of ethyl acetate and the structure of the Cu-solid base catalysts with Zn loading were discussed. The detected conversion of ethyl acetate reached 81.6% with a 93.8% selectivity of ethanol. This investigation of the Cu-Zn/$SiO_2$ catalyst provides a recently proposed pathway for ethyl acetate hydrogenation reaction to produce ethanol over Cu-solid base catalysts.

• Clean Technology
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• v.9 no.4
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• pp.189-196
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• 2003

ZnO-CuO mixed sorbents for desulfurization in hot gas cleaning process Were prepared and investigation on their characteristics was performed in this study. The rate of sulfidation increased as the amount of copper oxide in the composite sorbent was raised. TPO experiments were carried out to investigate the characteristics of the regeneration of the sorbents with severa1 different ratios of Zno to CuO. Copper sulfate was formed at temperatures above $400^{\circ}C$, while it was decomposed by pyrolysis above $700^{\circ}C$. $SO_2$ slippage due to $CuSO_4$ was observed in the sorbent regenerated at temperatures above $600^{\circ}C$. However, it was not observed when regenerated above $700^{\circ}C$. It was confirmed in the ZnO-CuO mixed sorbent system that CuO suppressed the vaporization of ZnO on the one hand and Zno minimized the $SO_2$ slippage due to CuO on the other hand.

• Korean Journal of Ichthyology
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• v.18 no.4
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• pp.293-299
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• 2006

Copper,zinc superoxide dismutase (Cu,Zn-SOD) plays a key role to the first antioxidant defense system against oxidative stress in diverse aerobic organisms. Due to the housekeeping action of Cu,Zn-SOD, it was reported that the structure and function have been conserved during evolution. In this study Cu,Zn-SOD from cloudy catshark Scyliorhinus torazame was subjected to phylogenetic analyses to know its evolutionary relationship in the vertebrate lineage. Molecular phylogenetic trees inferred by NJ, MP, ML and/or Bayesian analyses showed two shark species, Prionace glauca and S. torazame grouped together with high statistical supports. In general, they placed at the separated position from bony vertebrates. Thereafter, bony vertebrates composed of teleosts and birds/mammals (amniotes) formed a monophyletic group. Each teleost and amniote clade was also supported by relatively high statistical values. These phylogenetic relationships are well congruent with the phylogenetic hypothesis of the ancestral position of cartilaginous fishes to bony vertebrates.

• Journal of Sensor Science and Technology
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• v.29 no.3
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• pp.156-161
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• 2020

In this study, hierarchical mesoporous CuO spheres, ZnO flowers, and heterojunction CuO/ZnO nanostructures were fabricated via a facile hydrothermal method. The as-prepared materials were characterized in detail using various analytical methods such as powder X-ray diffraction, micro Raman spectroscopy, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, and transmission electron microscopy. The obtained results are consistent with each other. The H₂S-sensing characteristics of the sensors fabricated based on the CuO spheres, ZnO flowers, and CuO/ZnO heterojunction were investigated at different temperatures and gas concentrations. The sensor based on ZnO flowers showed a maximum response of ~141 at 225 ℃. The sensor based on CuO spheres exhibited a maximum response of 218 at 175 ℃, whereas the sensor based on the CuO/ZnO nano-heterostructure composite showed a maximum response of 344 at 150 ℃. The detection limit (DL) of the sensor based on the CuO/ZnO heterojunction was ~120 ppb at 150 ℃. The CuO/ZnO sensor showed the maximum response to H₂S compared with other interfering gases such as ethanol, methanol, and CO, indicating its high selectivity.

• Journal of the Korean institute of surface engineering
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• v.56 no.6
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• pp.451-456
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• 2023

Transparent conducting films having a three layered structure of ZnO/Cu/ZnO (ZCZ) were deposited onto the glass substrates by using RF and DC magnetron sputtering at room temperature. The emissivity and opto-electrical properties of the films were investigated with a varying thickness(5, 10, 15 nm) of the Cu interlayer. With increasing the Cu thickness to 15 nm, the films showed a enhanced electrical properties. Although ZnO 30/Cu 15/ZnO 30 nm film shows a lower resistivity of 5.2×10^-5 Ωcm, it's visible transmittance is deteriorated by increased optical absorbtion of the films. In addition, X-ray diffraction patterns indicated that the insertion of Cu interlayer improve the grain size of ZnO films, which is favor for the electrical and optical properties of transparent conducting films. From the observed low emissivity of the films, it is concluded that the ZCZ thin films with optimal thickness of Cu interlayer can be applied effectively for the car's window coating materials.

• Journal of Korea Foundry Society
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• v.22 no.2
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• pp.89-96
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• 2002

This study examined the effects of adding Zn to Sn-3.5Ag solder on the microstructure changes and behavior of interface reaction of the solder joint with Cu substrate. The solder/Cu joints were examined with microscope to observe the characteristics of microstructure changes and interfacial reaction layer with aging treatment for up to 120 days at $150^{\circ}C$. Results of the microstructure changes showed that the microstructures were coarsened with aging treatment, while adding 1%Zn suppresses coarsening microstructures. The Sn-3.5Ag/Cu had a fast growth rate of the reaction layer in comparison with the Sn-3.5Ag-1Zn at the aging temperature of $150^{\circ}C$. Through the SEM/EDS analysis of solder joint, it was proved that intermetallic layer was $Cu_6Sn_5$ phase and aged specimens showed that intermetallic layer grew in proportion to $t^{1/2}$, and the precipitate of $Ag_3Sn$ occur to both inner layer and interface of layer and solder. In case of Zn-containing composite solder, $Cu_6Sn_5$ phase formed at the side of substrate and Cu-Zn-Sn phase formed at the other side in double layer. It seems that Cu-Zn-Sn phase formed at solder side did a roll of banrier to suppress the growth of the $Cu_6Sn_5$ layer during the aging treatment.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.199-199
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• 2013

최근 단파장 광전 소자와 고출력 고주파 전자 소자에 대한 수요 때문에 넓은 밴드갭 에너지를 갖는 반도체에 관심이 많다. 이중에서, ZnO는 우수한 화학 및 역학적 안정성, 수소 플라즈마 내구성과 저가 제조의 장점 때문에 광전자 소자 개발 분야에 적합한 산화물 투명 전극으로 관심을 끌고 있다. 불순물이 도핑되지 않은 ZnO는 본질적으로 산소 빈자리 (vacancy)와 아연 격자틈새 (interstitial)와 같은 자체의 결함으로 말미암아 n형의 극성을 갖기 때문에, 반도체 소자로 응용하기 위해서는 도핑 운반자의 농도와 전도성을 제어하는 것이 필요하다. 본 연구에서는 박막 제조시 제어성, 안정성과 용이하게 성장이 가능한 졸겔 (sol-gel) 방법을 사용하여 사파이어와 석영 기판 위에 Cu가 도핑된 ZnO 박막을 성장시켰으며, 그것의 구조, 표면 형상, 평균 투과율, 광학 밴드갭 에너지를 계산하였다. 특히, Cu의 몰 비를 0, 0.01, 0.03, 0.05, 0.07, 0.1 mol로 변화시키면서 ZnO:Cu 박막을 성장시켰다. ZnO:Cu 졸은 zinc acetate dihydrate, 2-methoxyethanol (용매), momoethanolamine (MEA, 안정제)을 사용하여 제조하였다. 상온에서 2-methoxyethanol과 MEA가 혼합된 용액에 zinc acetate dihydrate (Zn)을 용해시켰다. 이때 MEA와 Zn의 몰 비는 1로 유지하였다. 이 용액을 $60^{\circ}C$ 가열판 (hot plate)에서 24 h 동안 자석으로 휘젓으며 혼합하여 맑고 균일한 용액을 얻었다. 이 용액을 3000 rpm 속도로 회전하는 스핀 코터기의 상부에 장착된 사파이어와 석영 기판 위에 주사기 (syringe)를 사용하여 한 방울 떨어뜨려 30 s 동안 스핀한 다음에, 용매를 증발시키고 유기물 찌꺼기를 제거하기 위하여 $300^{\circ}C$에서 10분 동안 건조시킨다. 기판 위에 코팅하는 작업에서 부터 건조 작업까지를 10회 반복한 다음에, 1 h 동안 전기로에 장입하여 석영 기판 위에 증착된 시료는 $550^{\circ}C$에서, 사파이어 기판은 $700^{\circ}C$에서 열처리를 수행하였다. Cu의 몰 비 0, 0.01, 0.03, 0.05, 0.07, 1로 성장된 ZnO:Cu 박막에 대한 x선 회절 분석의 결과에 의하면, 모든 ZnO:Cu 박막의 경우에 관측된 34.3o의 피크는 ZnO (002) 면에서 발생된 회절 패턴을 나타낸다. 이것은 JCPDS #80-0075에 제시된 회절상과 일치하였으며, ZnO:Cu 박막이 기판에 수직인 c-축을 따라 우선 배향됨을 나타낸다. 사파이어 기판 위에 증착된 박막의 경우에, Cu의 몰 비가 점점 증가함에 따라(002)면 회절 피크의 세기는 전반적으로 증가하여 0.07 mol에서 최대를 나타내었으나, 석영 기판 위에 증착된 박막의 경우에는 0.05 mol에서 최대를 보였다. 외선-가시광 분광계를 사용하여 서로 다른 Cu의 몰 비로 성장된 ZnO:Cu 박막에서 광학 흡수율 (absorbance) 스펙트럼을 측정하였으며, 이 데이터를 사용하여 평균 투과율을 계산한 결과, 투과율은 Cu의 몰 비에 따라 현저한 차이를 나타내었다. Cu의 몰 비가 0.07 mol일 때 평균 투과율은 80%로 가장 높았으며, 0.03 mol에서는 30%로 최소이었다. 광학밴드갭 에너지는 Tauc 모델을 사용하여 계산하였고, 결정 입자의 형상과 크기와의 상관 관계를 조사하였다.

• Economic and Environmental Geology
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• v.47 no.4
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• pp.405-420
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• 2014

To investigate geochemical characteristics of soil and atmospheric environments by anthropogenic source, we have analyzed and determined heavy metal concentrations of the surface soils beneath roadside trees and leaves of Platanus occidentalis from 52 points in Seoul during autumn 2001. For comparison of the contents of heavy metal for the soil and leaf, we have analyzed heavy metal contents of the surface soils beneath roadside trees and leaves from 2 points in rural area of Yesan during the same time period. The composition of heavy metals of soils are relatively high for Cd, Co, Cr and Ni in industrial area (IA, Industrial Area) and high for Cu, Pb and Zn in heavy traffic area (HTA, Heavy Traffic Area). The heavy metal contents of rural area in Seoul are higher than those in Yesan. The differences of chemical compositions between the washed and unwashed leaves are high for Cd, Cu, Pb and Zn in the HTA. The element couples of Cd-Co, Cr-Ni and Pb-Zn for the soils had shown a good correlation and their contamination sources could be similar. The relationship for Pb-Cu and Cu-Zn showed good correlation in Platanus leaves. The relationship between soils and unwashed leaves show a good correlation for Cr, Cu, Pb and Zn but low correlation for Cd, Co, Fe, Mn and Ni. It is thought that the Cr, Cu, Pb and Zn were derived from contaminants of soils, whereas Cd, Co, Fe, Mn and Ni were originated from atmospheric source. From the spatial variations of elements for soils and leaves, Ni and Cr were dominant in the soils of IA and Cd, Cu and Zn were dominant in those of HTA. The Contamination by Cd-Pb and Cu-Zn in unwashed leaves were analyzed to show similar patterns. Using the enrichment factors (EF) of heavy metals in unwashed leaves, the EF sequences were to be Cu, Zn, Pb, Mn, Co, Ni, Cd and Cr. We identified that Cu, Zn, Pb and Mn were most problematic of environmental hazard in Seoul.