• Title/Summary/Keyword: PbSe

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A Study of Preparation of Antiferroelectric PbZrO3 Thin Films by Sol-Gel Processing (Sol-gel법에 의한 반강유전성 PbZrO3 박막 제작에 관한 연구)

  • Jeon, Kie-Beom;Bae, Se-Hwan
    • Journal of Korean Ophthalmic Optics Society
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    • v.3 no.1
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    • pp.15-19
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    • 1998
  • The purpose of this study, when one prepared lead zirconate thin films by sol-gel method, was to find the preferred direction of crystal growth and dielectric characteristics for ratio of Pb and Zr. We used the Pt/Ti/$SiO_2$/Si substrate, and annealing condition was $800^{\circ}C$ for lminute. When Pb was deficient, preferred direction was <221>. And when it was stoichiometric ratio, they were grown <200> and <221> direction. But they have antiferroelectric properties, they don't appear distinct domain switching.

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Geology and Ore Deposits of Yeonhwa Mine (연화광산(蓮花鑛山)의 지질광상(地質鑛床))

  • Han, Kap Soo
    • Economic and Environmental Geology
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    • v.2 no.3
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    • pp.47-57
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    • 1969
  • The Yeonhwa Lead and Zinc Mine is located in northern part of Kyeongsang-Buk-Do, Korea, and is economically most important mine because it produces most part of the output of lead and zinc minerals in the country. Ore deposits of the mine are localized in the Pungchon Formation and several limestone seams of upper Myobong Formation in Cambrian Age. Ore solution ascended along the fractures of N-S, NE-SW or NW-SE trends and along slate and limestone boundary, and then replaced selectively limestone to make ore bodies. Skarn minerals are consisted of hedenbergite, diopside, and main sulfide mineral orebodies are composed of galena, zincblende, pyrrhotite, pyrite and a minor amounts of arsenopyrite and chalcopyrite. Metal ratio, ${\rho}_{Pb}={\frac{Pb(%)}{Pb(%)+Zn(%)}}{\times}100$, illustrates the zona I arrangements of some ore bodies. It will be inferred the flow trending of ore solution and the process reaction with adjacent country rocks. The sub-divided formations of the Pungchon limestone and Myobong slate are very useful as a criteria for detecting probable ore location. Rhodochrosite veins are good evidence for searching of ore location, especially on Pb-rich ore bodies.

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A Study on the Mineral Contents in Edible Mushrooms Produced in Korea (한국산 식용버섯의 무기성분 함량에 관한 연구)

  • 안장수;이규한
    • Journal of Food Hygiene and Safety
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    • v.1 no.2
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    • pp.177-179
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    • 1986
  • ABSTRACT$.$Seven species of mushrooms (Sarcodon asparatus, Agaricus bisporus. Calocybe gambosa, Len tin us ,edodes.Ramariabotrytis.Pleurotus ostreatus and Tricholoma matsutake) produced in Korea were investigated on their mineral contents mainly by using Inductively coupled plasma-technique. The obtained results are summerized as follows: 1) Fe, N a and Zn are relativel highly contained in almost all mushrooms tested in this study. 2) Harmful elements such as Cd, Hg. Pb and As, were found only in trace amounts. 3) Sb, Se and Sn were not detected in all mushrooms.hrooms.

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Se Electrode for Low Surge Vacuum Circuit Breaker (저surge 진공 차단기용 Se 전극 제조)

  • Kim, Bong-Seo;Woo, Byung-Chul;Byun, Woo-Bong;Lee, Hee-Woong
    • Proceedings of the KIEE Conference
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    • 1996.07c
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    • pp.1651-1653
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    • 1996
  • As electrode materials like as Cu-Pb, Cu-Bi, WC-Ag, W-Ag for vacuum circuit breaker have high chopping current or bad insulation-recovery characteristics, it can affect induction machinery like as transformer and motor. To produce low surge electrode material, it have been suggested Co-Ag-Se electrode which were infiltrated with Ag-Se intermetallic compound into sintered Co matrix. In this study, we would like to represent that production method and microstructure of Co-Ag-Se electrode material. The microstructure and characteristics of Ag-Se intermetallic compound and Co-(Ag-Se) electrode were investigated by using SEM, XRD, EPMA.

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Trace metals and selenium in organs and tissues of the striped field mice, Apodemus agratius, collected from Korea (한국산 등줄쥐 각 조직에 분포하는 미량금속류 및 셀레늄에 관한 연구)

  • 윤명희;노영희
    • Journal of Environmental Science International
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    • v.8 no.4
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    • pp.515-523
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    • 1999
  • Nine trace metals (Zn, Fe, Al, Pb, Mn, Cu, Ni, Cr, and Cd) and Se concentrations were determined in organs and tissues(muscle, bone, kidney, liver and skin) of the striped field mice, Apodemus agrarius collected at Daejeo-dong, Pusan city and the Sorak Mt., Kangwon Province. All the trate elements were detected from all the mice examined. As for the metal concentrations in the mice from Daejeo-dong, Zn, Fe, Al, Mn, Ni and Cr were significantly higher than those in Sorak Mt.(p<0.05), suggesting that pesticides including Zn and factory wastes containing several metals might contaminated the environment of Daejeo-dong. As regards the element concentrations in each organ and tissue, Fe, Al, Pb, Mn, Cu, Cr and Cd concentrations were high in liver or kidney; Zn in skin and bone; Ni in bone, skin and kidney; and Se in muscle, liver and skin in all the mice examined. There were significant differences(p<0.05) between juveniles and adults in average concentration of metals(Zn, Fe, Pb, Mn, Ni, and Cd) in every organs and tissues of mice collected at Daejeo-dong. Much higher average levels of metals in juveniles indicate that considerable burdens fo metals might be transferred through the placenta. However, there were no significant differences between males and females, and between young and old adults in average metal concentrations, which suggests that the mice might accumulate the metals during their life time, although they might excrete the metals not only through reproductive activities, such as parturition, lactation and ejaculation of semen, but also through molting, judging from higher accumulating ratios of most metals in skin of adults than of juveniles.

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Development and Properties of Carbon monoxide Detector for Ambient Air monitoring (대기오염 측정용 일신화 탄소 검출기의 제작 및 특성)

  • Cho, Kyung-Haeng;Lee, Sang-Wha;Lee, Joung-Hae;Choi, Kyong-Sik
    • Analytical Science and Technology
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    • v.13 no.2
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    • pp.222-228
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    • 2000
  • A detector for monitoring carbon monoxide (CO) in ambient air by nondispersive infrared (NDIR) spectroscopy has been developed and investigated its sensitivity and stability. The essential parts of the absorption cell are three spherical concave mirrors so as to improve the sensitivity by increasing the light path length in the cell. The radius and center of curvature of mirrors and position in the cell was calculated by computer simulation in order that the light path length may be 16m into the 50cm cell. The number of traversals and optical path properties were confirmed by laser beam alignment in transparent absorption cell. The photoconductive type lead selenide (PbSe) was used as CO sensing material, which was cooled to increase the responsibility by thermoelectric cooling method. The detection limit and span drift of the developed CO detector was 0.24ppm and 0.03ppm(v/v) respectively.

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$3^{rd}$ Overtone Mode Energy-Trapped Filter Using $PbTiO_{3}$ System Ceramics ($PbTiO_{3}$계 조성 세라믹스를 이용한 3차 진동모드 에너지 트랩형 필터에 관한 연구)

  • Oh, Dong-On;Yoo, Ju-Hyun;Park, Chang-Yub;Yoon, Hyun-Sang;Lee, Su-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.11a
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    • pp.83-86
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    • 2002
  • In this paper, $3^{rd}$ overtone mode energy-trapped filter using modified $PbTiO_3$ system ceramics was manufactured to apply for intermediate frequency SMD-type filter with the variations of splitted electrode size. To investigate the effects of splitted electrode size on filter characteristics of $3^{rd}$ overtone mode energy-trapped filter, ceramic wafers were fabricated by etching splitted rectangular electrode size($b{\times}d$) of b=0.4, 0.6, 0.8, 1mm, d=0.3, 0.4, 0.5mm, respectively. And then, SMD-type ceramic filter were fabricated with the size of $3.7{\times}3.1mm$. With the variations of b size, insertion loss, 3dB bandwidth and 25dB stop bandwidth showed nearly constant value, but with the variations of d size, insertion loss, 3dB bandwidth, selectivity(shape factor) decreased.⨀؀က?⨀Ⴣ?⨀਀Ⴣ?⨀ꞻꎀ̀ကꮻꎀༀ뮻ꎀ᠀Ȁ햻ꎀĀힻꎀȀ?ꎀ̀?ꎀȀꎀĀꎀĀꎀĀꎀĀꎀЀȀꎀࠀꎀഀڼꎀഀᒼꎀ؀ᮼꎀ䈀ȀȀ悼ꎀऀ檼ꎀഀȀ禼ꎀഀ螼ꎀऀȀȀ鎼ꎀഀȀꊼꎀഀ낼ꎀࠀ즼ꎀԀ쾼ꎀ܀ힼꎀ

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Comparison of the Heavy Metal Analysis in Soil Samples by Bench-Top ED-XRF and Field-Portable XRF (Bench-Top ED-XRF 및 휴대용 XRF를 이용한 토양 시료 중의 중금속 비교 분석)

  • Choi, Soo-Jung;Kim, Chong-Hyeak;Lee, Sueg-Geun
    • Analytical Science and Technology
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    • v.22 no.4
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    • pp.293-301
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    • 2009
  • As a basic research for development of the domestic field-portable XRF spectrometer, we discussed the analytical results of bench-top ED-XRF and field-portable XRF method for polluted heavy metals such as Cr, As, Se, Hg, Pb, Cd in soil samples. To obtain the best performance of the XRF spectrometer, the instrumental parameters of X-ray tube-voltage and measurement time were optimized for 6 heavy-metal elements in soil using certified reference material. The quantitative analysis of Cr, As, Se, Hg, Pb, Cd concentration in certified reference materials and soil samples were compared by empirical method and fundamental parameter method.

Removal Effects of Pb(II) using Natural Clays from Domestic (국내산 천연점토를 이용한 Pb(II)의 제거효과)

  • Oh, Se-Young;Hwang, Seong-Kwy;Yoon, Cheol-Hun;Lee, Ki-Chang;Jang, Kwan-Sik
    • Journal of the Korean Applied Science and Technology
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    • v.15 no.3
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    • pp.13-19
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    • 1998
  • This study was carried out to investigate characteristics and Pb(II) removal effect of natural Muan, Seosan, Kangjin clays in the batch mode test to develope the low-priced treatment agent of wastewater which contain heavy metals in order structural, optical properties and chemical compositions of natural clays from domestic have been investigated to have high specific surface area and have minerals such as $SiO_2$ and $Al_2O_3$. As a result, removal effects of Pb(II) ions on clays were reached at equilibrium in aqueous solutions by stirring about 20minutes. The removal effect of Pb(II) ions was best for Seosan clay than Muan or Kangjin clays in terms of fixed time. The results show the possibility of continuous treatment system of wastewater which contain heavy metals by using natural clays from domestic.