• Title/Summary/Keyword: CD7

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ZnTe:O/CdS/ZnO intermediate band solar cells grown on ITO/glass substrate by pulsed laser deposition

  • Lee, Kyoung Su;Oh, Gyujin;Kim, Eun Kyu
    • Proceedings of the Korean Vacuum Society Conference
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    • 2015.08a
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    • pp.197.2-197.2
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    • 2015
  • Low-cost, high efficiency solar cells are tremendous interests for the realization of a renewable and clean energy source. ZnTe based solar cells have a possibility of high efficiency with formation of an intermediated energy band structure by impurity doping. In this work, the ZnTe:O/CdS/ZnO structure was fabricated by pulsed laser deposition (PLD) technique. A pulsed (10 Hz) Nd:YAG laser operating at a wavelength of 266 nm was used to produce a plasma plume from an ablated a ZnTe target, whose density of laser energy was 4.5 J/cm2. The base pressure of the chamber was kept at a pressure of approximately $4{\times}10-7Torr$. ZnO thin film with thickness of 100 nm was grown on to ITO/glass, and then CdS and ZnTe:O thin film were grown on ZnO thin film. Thickness of CdS and ZnTe:O were 50 nm and 500 nm, respectively. During deposition of ZnTe:O films, O2 gas was introduced from 1 to 20 mTorr. For fabricating ZnTe:O/CdS/ZnO solar cells, Au metal was deposited on the ITO film and ZnTe:O by thermal evaporation method. From the fabricated ZnTe:O/CdS/ZnO solar cell, current-voltage characteristics was measured by using HP 4156-a semiconductor parameter analyzer. Finally, solar cell performance was measured using an Air Mass 1.5 Global (AM 1.5 G) solar simulator with an irradiation intensity of 100 mW cm-2.

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Immunotoxicological Investigation of 1-furan-2-yl-3-pyridin-2-yl-propenone in Female BALB/c Mice

  • Jeon, Tae-Won;Kim, Chun-Hwa;Lee, Sang-Kyu;Ko, Gyu-Sub;Yoo, Jin-Woo;Ha, Hyun-Woo;Kang, Won-Ku;Jeong, Hye-Gwang;Kang, Mi-Jeong;Lee, Eung-Seok;Jeong, Tae-Cheon
    • Biomolecules & Therapeutics
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    • v.17 no.4
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    • pp.446-454
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    • 2009
  • 1-Furan-2-yl-3-pyridin-2-yl-propenone (FPP-3) has recently been synthesized and characterized to have an anti-inflammatory activity through the inhibition of the production of nitric oxide and tumor necrosis factor-$\alpha$. In the present study, adverse effects of FPP-3 on immune functions were determined in female BALB/c mice. When mice were administered orally with FPP-3 at 125, 250 or 500 mg/kg for 7 consecutive days, FPP-3 suppressed the number of antibody-forming cells and reduced thymus weight at 500 mg/kg. In addition, FPP-3 administered mice exhibited reduced splenic cellularity and numbers of splenocyte subsets, such as $CD3^+$ cells, $CD3^+CD4^+$ cells, $CD3^+CD8^+$ cells and macrophages. IL-4 mRNA expression was significantly suppressed by FPP-3 treatment. Moreover, the number of $CD4^+IL-4^+$ cells was reduced following the treatment of mice with 500 mg/kg of FPP-3. These results suggested that FPP-3 at 500 mg/kg might be immunotoxic, and that FPP-3-induced immunotoxicity might be mediated, at least in part, through the inhibition of cytokine production, such as IL-4.

Flexible CdS Films for Selective control of Transmission of Electromagnetic Wave (유연성 기판위에 스퍼터링법으로 제조한 CdS 박막의 전자파차폐 특성평가)

  • Hur, Sung-Gi;Cho, Hyun-Jin;Jung, Hyun-Jun;Ahn, Jun-Ku;Yoon, Soon-Gil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.27-27
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    • 2009
  • Non-stochiometric CdS:H films grown on polyethersulfon (PES) flexible polymer substrates at room temperature by R.F. sputtering technique. They exhibited a dark- and photo-sheet resistance of $2.7\times10^5$ and $\sim\;50\;{\Omega}$/square, respectively. These values were realized by an optimum control of both hydrogen doping-levels and the surface morphologies of the films. The comparison between the real and the simulated results for the shielding and the transmission by the free space measurement system in the X-band frequency range (8.2 - 12.4 GHz) was also addressed in this study. Samples overlapped with 13 layers of CdS:H/PES were consistent with the transmission results of pure aluminum metal films ($0.1\;{\Omega}$/square) deposited on PES substrates. As a result, by the simples tacking of the CdS:H/PES layers, the perfect control of the shielding and the transmission of the EM wave in the range of X-band frequency is possible by avisible light alone, and their results are especially very outstanding findings in the stealth function of the radome(Radar+Dome) such as aircrafts, ships, and missiles.

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A Study on the Electrochemical Deposition and p-Type Doping of ZnTe Films as a Back Contact Material for CdTe Photovoltaic Solar Cells (CdTe계 태양전지에 응용되는 ZnTe 박막의 전기화학적 제조 및 Cu 도핑 연구)

  • Kim, Dong-Hwan;Jeon, Yong-Seok;Kim, Gang-Jin
    • Korean Journal of Materials Research
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    • v.7 no.10
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    • pp.856-862
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    • 1997
  • 박막형 CdTe/CdS 태양전지의 배면전극(back contacts)물질로서 Cu도핑된 ZnTe 박막(ZnTe:Cu)을 전착법(electroplating)으로 제조하는 연구를 수행하였다. Sulfate계의 전해질 수용액에서 CdTe 기판과 투명전극으로 코팅된 유리(In$_{2}$O$_{3}$: Sn, ITO)기판 위에 ZnTe 박막을 코팅하는 방법으로써 potentiostat와 기판(cathode), Pt counter electrode, Ag/AgCI 표준전극으로 구성된 장치를 사용하여 pH=2.5-4, T=70-8$0^{\circ}C$, 0.02M $Zn^{2+}$ 1x$10^{-4}$M TeO$_{2}$, 0.2M $K_{2}$SO$_{4}$조건에서 -0.800 Vs~-0.975 V 범위의 전압(V$_{a}$ )에 걸쳐 실험하였다. ITO박막을 기판으로 사용하여 cyclic voltammogram을 작성한 결과 약 -0.50 V 에서 Te환원 peak이 나타났다. Auger electron spectroscopy (AES)로 조성분석한 결과 표면에서 Zn signal이 강하게 나왔고 시편의 두께에 따라 Zn의 signal감소하는 반면 Cd signal은 증가하는 것이 확인되었다. SEM 사진으로부터 ZnTe의 표면이 작은 입자 (0.2$\mu\textrm{m}$ 이하)로 구성되어 있으며 낮은 V$_{a}$ 에서는 입자가 작아지면서 조직이 치밀해짐이 관찰되었다. Optical transmission방법에 의하여 ITO기판위에 입혀진 박막의 밴드갭은 2.5 eV으로 측정되었다. 수용액중의 Cu$_{2+}$와 triethanolamine(TEA)은 산성용액에서 착물형성이 이루어지지 않았으며 1,10-phenanthroline과는 pH=2에서도 착물이 형성되었다.

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Extraction of Cd and Pb from Soil by Anionic Surfactant and Ligand NaI (NaI 리간드화 계면활성제에 의한 토양내 Cd과 Pb 추출 연구)

  • Heo, Jung-Hyun;Jeong, Seung-Woo
    • Journal of Soil and Groundwater Environment
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    • v.13 no.5
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    • pp.74-80
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    • 2008
  • Heavy metals, Cd and Pb, in soil were extracted by using anionic surfactants such as AOS (alpha olefin sulfonate), SDS (sodium dodecyl sulfate), and LAS (linear alkyl benzene sulfonic acid). Metal extractability from soil was affected by the carbon number and solution pH of surfactants. LAS showed higher metal extractability due to the acidic solution condition. Although SDS has a fewer carbon number than AOS, it would produce smaller micelles and resulted in more efficient extraction of metals by increased soil contact. Cd extractability of surfactant was twice enhanced by adding NaI as a ligand. However, Pb extractability of surfactant was sometimes reduced by adding NaI. Those ligand effects were dependent on solubility of metal-ligand. The column experiment also showed that SDS having smaller micelles resulted in higher metal extractability than AOS.

Application of Practical Immobilizing Agents for Declining Heavy Metal (loid)s Accumulation by Agricultural Crop (Allium wakegi Araki)

  • Seo, Byoung-Hwan;Kim, Hyun-Uk;Lwin, Chaw Su;Kim, Hyuck Soo;Kim, Kwon-Rae
    • Korean Journal of Soil Science and Fertilizer
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    • v.50 no.4
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    • pp.226-234
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    • 2017
  • In order to reduce the accumulation of toxic metals (As, Cd and Pb) in the chives, various immobilizing agents such as a soil pH change-inducing immobilizing agent (lime), sorption agent (compost, spent mushroom compost), soil pH change and sorption agent (biochar) and, dissolved organic carbon (DOC) coagulator (gypsum) and uncontaminated soil were applied to the contaminated soils in isolation and in combination. Then chives were grown and determined for As, Cd and Pb concentrations accumulated in the edible part at harvest. The Cd and Pb concentrations of the chive plant grown in the contaminated soil (no treatment) exceeded the legislated Korean guideline values (Cd: $0.05mg\;kg^{-1}$, Pb $0.1mg\;kg^{-1}$) and As concentration ($21mg\;kg^{-1}$) was 1,000 times higher than chives plant grown in uncontaminated environment in Korea. Application of lime and gypsum significantly reduced As, Cd and Pb concentrations in all chives examined, due to the increased soil pH and decreased soil DOC. Also, application of combination treatments involving DOC coagulator such as gypsum together with lime decreased As, Cd and Pb concentrations from 21, 1.3 and $9.7mg\;kg^{-1}$ to 2.1, 0.1 and $1.1mg\;kg^{-1}$, respectively. Consequently, it was concluded that pH change-inducing immobilizing agent (lime) which was already well known and DOC coagulator such as gypsum could be used as a promising immobilizing agent for safer chives plant production.

Fabrication and characterization of CdS photoconductive cell by the print/sintering method (인쇄/소결 방법에 의한 CdS 광전도 셀 제작과 특성)

  • Jeong, Tae-Soo;Kim, Taek-Sung;Jeong, Cheol-Hoon;Lee, Hoon;Shin, Yeong-Jin;Hong, Kwang-Joon;Yu, Pyeong-Yeol
    • Journal of Sensor Science and Technology
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    • v.7 no.5
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    • pp.350-355
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    • 1998
  • We fabricated a photoconductive cell made of polycrystalline CdS thick film which has high photo-sensitivity using a print/sintering method. The resultant grain size is about $4\;{\mu}m$. When $CuCl_2$ of 0.06 to 0.12 mg is added, the sensitivity and the ratio of photocurrent to dark current are 0.8 and $10^5$, respectively. The response wavelength is 511 nm. The rise and decay response times are 50 and 20 ms, respectively. In addition, the maximum power dissipation is beyond 80mW. We noticed that the addition of $CuCl_2$ between 0.06 and 0.12 mg to 1g of CdS results in a reliable formation of photoconductive sensor.

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Photocurrent Study on the Splitting of the Valence Band and Growth of $CdIn_2S_4$/GaAs Single Crystal Thin Film by Hot Wall Epitaxy (Hot Wall Epitaxy(HWE)법에 의해 성장된 $CdIn_2S_4$ 단결정 박막의 가전자대 갈라짐에 대한 광전류 연구)

  • Baek, Seung-Nam;Hong, Kwang-Joon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.79-80
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    • 2006
  • A stoichiometric mixture of evaporating materials for $CdIn_2S_4$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $CdIn_2S_4$ mixed crystal was deposited on thoroughly etched semi-Insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The temperature dependence of the energy band gap of the $CdIn_2S_4$ obtained from the absorption spectra was well described by the Varshni's relation. $E_g(T)=2.7116 eV-(7.74{\times}10^{-4} eV)T^2/(T+434)$. The crystal field and the spin-orbit splitting energies for the valence band of the $CdIn_2S_4$ have been estimated to be 0.1291 eV and 0.0248 eV, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}_5$ states of the valence band of the $AgInS_2$/GaAs epilayer. The three photocurrent peaks observed at 10K are ascribed to the $A_1-$, $B_1-$, and C1-exciton peaks for n = 1.

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Growth and Optical Properties for $CdGa_2Se_4$ epilayer by Hot Wall Epitaxy (Hot Wall Epitaxy (HWE)에 의한 $CdGa_2Se_4$ 박막 성장과 광학적 특성)

  • Hong, Myoung-Seok;Hong, Kwamg-Joon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.125-126
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    • 2006
  • The stochiometric mix of evaporating materials for the $CdGa_2Se_4$ single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films. $CdGa_2Se_4$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were $630^{\circ}C$ and $420^{\circ}C$, respectively. The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CdGa_2Se_4$ single crystal thin films measured from Hall effect by van der Pauw method are $8.27{\times}10^{17}cm^{-3}$. $345cm^2/V{\cdot}s$ at 293 K, respectively. From the photoluminescence measurement on $CdGa_2Se_4$ single crystal thin film, we observed free excition ($E_x$) existing only high quality crystal and neutral bound exiciton ($D^{\circ},X$) having very strong peak intensity. Then. the full-width-at -half-maximum(FWHM) and binding energy of neutral donor bound excition were 8 meV and 13.7 meV, respectivity. By Haynes rule. an activation energy of impurity was 137 meV.

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A Survey of Soil Pollution in Pusan City Area (부산시 일원의 토양 오염도 조사)

  • Chung, In-Kyo;Hong, Seong-Soo;Yun, Il
    • YAKHAK HOEJI
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    • v.38 no.6
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    • pp.725-732
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    • 1994
  • To provide a basis for setting up an environmental pollution policy of Pusan, an investigation of metal contents in the soil of Pusan was carried out from May, 1993 to April, 1994. Soil was sampled from 10 sites of industrial area,8 sites of commercial area, 8 sites of residential area, 8 sites of green area and 8 sites of agricultural area. The industrial area was the most heavily polluted and the average contents of Cd, Cu, Zn, Mn, Pb and As were 0.580, 19.377, 67.348, 59.638, 58.555 and 1.006 ppm, respectively. In the soil of commercial area, the average contents of Cd, Cu, Zn, Mn, Pb and As were 0.453, 19.110, 63.384, 56.006, 37.466 and 0.578 ppm, respectively, and the average contents of Cd, Cu, Zn, Mn, Pb and As were 0.289, 10.312, 55.246, 55.536, 17.695 and 0.610 ppm, respectively, in the soil of residential area. The green area was the least polluted and the average contents of Cd, Cu, Zn, Mn, Pb and As were 0.215, 5.949, 19.366, 37.244, 6.856 and 0.295 ppm, respectively. In the soil of agricultural area, the average contents of Cd, Cu, Zn, Mn, Pb and As were 0.160, 7.077, 25.365, 51.485, 10.607 and 0.499 ppm, respectively The fact that the Cd content of agricultural area was lower than that of green area is remarkable.

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