• 한국초전도ㆍ저온공학회논문지
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• 제14권4호
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• pp.12-15
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• 2012

$MgB_2$ superconductor is highly sensitive to the Mg content. Even if the samples are synthesized with the appropriate looking stoichiometric ratio, the heat treatment leads to the loss of Mg either to ambiance or to MgO. To avoid it, either excess Mg is added in the starting powder or sealed ampoule annealing is employed. In this paper the effect of open Mg sintering ambiance on the ex-situ $MgB_2$ was studied to enhance its superconducting properties. The open Mg ambiance was created to avoid any overpressure of Mg by providing a hole in Fe tube used as sample holder. The decrease in resistivity of the synthesized sample was observed through the increased temperature dependence of electron-phonon interactions. A clear enhancement in the superconducting cross-sectional area and hence the in-field critical current density is obtained.

• 공업화학
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• 제25권4호
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• pp.374-379
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• 2014

기록물 보존을 위한 탈산처리 완료 후 탈산제 성분인 MgO 입자가 기록물 표면에 미세 입자 형태로 남아있는 일명 백화현상이 나타나고 있다. 이 MgO 미세입자에 의한 백화현상은 MgO 입자가 분산되어 종이의 섬유질에 흡착함으로써 탈산효과를 나타내야 하나, MgO 입자의 농도와 입자크기가 적합하지 않을 경우 분산이 잘 이루어지지 않아 종이표면에 과량 흡착됨으로써 흰색인 MgO 미세입자로 입혀지는 현상이다. 이는 작업환경의 저해를 가져오고 또한 탈산처리 시 작업자 건강에 대한 우려가 증대되고 있으나, 이에 대한 원인 규명 및 대책은 없는 상황이다. 따라서 백화현상의 원인 규명 및 향후 대책을 수립하기 위하여 국내외에서 널리 사용되는 탈산제의 물성분석과 탈산제의 주요성분인 MgO 입자 크기 및 함량 변화에 따른 탈산 실험을 수행하였다. 탈산 실험은 산성지와 백상지를 사용하였으며, 탈산처리 후 SEM 기기분석으로 MgO 입자의 산성지 및 백상지의 지류 표면 흡착정도를 비교하였다. 실험결과 MgO 입자크기가 847 nm 크기로 유지되는 경우 실험한 두 종류의 지류 모두에서 백화현상이 현저하게 감소되는 것을 확인하였으며, MgO 입자크기가 백화현상의 주요 원인이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 학술대회 논문집 전문대학교육위원
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• pp.72-74
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• 2002

In this paper, we showed the erosion characteristics of MgO protector layer releated to lifetime of plasma display panel(PDP). We observed MgO erosion characteristic as a functions of deposition conditions. In RIE condition of Xe gas, the lowest erosion rate appears in the conditions of no heating, bias voltage -30V and pressure 5mtorr. In general. as deposition rate increases, erosion rate decreases.

• Journal of Advanced Marine Engineering and Technology
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• 제9권3호
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• pp.240-249
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• 1985

This paper presents the results of the galvanic anode's characteristicsin the Al-Zn-In-Mg and Al-Zn-In-Mg system anodes used aluminium ingot of low purity, 99.5% grade. The results of thses performance tests are as follows: 1) Zn, In and Mg are an available elements to improve the performance of Aluminium alloy anodes. 2) When the range of zinc content in the Al-Zn-In-Mg system anode is 2-5% the more zinc content, the more improve the anode performance. 3) Al-Zn-In-Mg system anode requires a long term over 50 days for the performance test. 4) The composition of Al-Zn-In-Mg system anode which shows the most excellent performance is Al-(2-3%) Zn-(0.02%) In-(1.0%) Mg. 5) When the Al-Zn-In-Mg system anode is annealed for an hour in 500 to 550 .deg. C, the anode performance is improved. 6) The lower average potential and the better corrosion pattern in the Al-Zn-Mg, Al-Zn-In and Al-Zn-In-Mg system anodes, the more current efficiency is improved.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1388-1390
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• 2007

This paper investigates how various concentrations of lithium ion influence on crystallization of MgO in thin films formed by spin coating and an the discharge characteristic in a flat fluorescent lamp structure. The XRD results indicate $Li^+$ ion enhances the growth of MgO crystal in a spin coated thin film. The discharge property with the $Li^+$ ion doped MgO films show the lithium ion in MgO film clearly reduce the initial discharge voltages of test devices. Interestingly, the test panels with various doped MgO film have somewhat higher static memory margin of than that of pure-MgO owing probably to the pore structure of spin coated MgO films. The CL spectra, which confirm that the doping creates defects energy levels in the band gap of MgO, show the $F^+$ center is the main defects in doped MgO films.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.307-310
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• 1998

In this paper, $Al_2$O$_3$/MgO belayer was prepared with Electron-beam evaporation and the properties of the film was investigated in order to improve the property of MgO film, which is used for the protection layer in PDP(Plasma Display Panel). $Al_2$O$_3$/MgO belayer were improved of roughness and it were condensed by annealing, and the result of XPS analysis for $Al_2$O$_3$/MgO belayer unchanged binding energy. To investigate electric characteristics, discharge properties of $Al_2$O$_3$/MgO belayer were compared with discharge minimum voltage for MgO monolayer through Ar discharge experiments.

• Tribology and Lubricants
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• 제20권2호
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• pp.97-101
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• 2004

This paper reports the studies on the wear-corrosion behavior of Al-Mg alloy in various pH environments. In various pH of sea water, corrosion and wear-corrosion loss of Al-Mg alloy were investigated. Also, the polarization test of Al-Mg alloy using potentiostat/galvanostat was carried out. And the rubbed surface of Al-Mg alloy using scanning electron micrographs after wear-corrosion test was examined in various pH values of sea water. The main results are as following : The polarization resistance of Al-Mg alloy in pH 4 solution is higer than that in pH 6.7 solution, and the corrosion current density in pH 4 is controlled than in pH 6.7 solution. The wear-corrosion loss of Al-Mg alloy with lowering pH becomes sensitive. As the oxide product of Al-Mg alloy appears granular structure and exholiation phenomenon, wear-corrosion loss of Al-Mg alloy increases.

• 한국해양학회지
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• 제12권1호
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• pp.41-47
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• 1977

The present paper deals with nine kinds of trace metal contents among 79 samples, more than 20 species of edible marine algae collected during 1973∼1975 along the coasts of Korea. Among the metals detected by the atomic absorption spectrometer, Mg content is variable in 2.09∼13.84mg/g-dry on an average and 5.31mg/g-dry in a mean of green, brown and red algae, whereas Fe is 0.148∼2.343 and 0.747mg/g-dry; Mn 0.015∼0.191 and 0.063mg/g-dry; Zn 0.007∼0.082 and 0.030 mg/g-dry; Cu 0.005∼0.054 and 0.017mg/g-dry; Pb 0.0017∼0.082 and 0.0043mg/g-dry Co 0.0009∼0.0024 and 0.0016mg/g-dry; Cd 0.0002∼0.0034 and 0.0011mg/g-dry, and Cr is 0.0007∼0.0074 and 0.0021mg/g-dry, both on an average and in a mean respectively. The trace metal contents in the seaweeds investigated are variable according to species, collecting seasons, places and kinds of metal It is interesting that in Sargassum thunbergii some metal contents such as Fe, Mn, and Zn are specially high in September1974 through the year investigated.

• 동아시아식생활학회지
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• 제17권5호
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• pp.696-702
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• 2007

The purpose of this paper is to describe the differences in mineral, ascorbic acid, and total polyphenol content, and also the relationship between polyphenol content and antioxidant activity(DPPH radical scavenging, FTC, and TBA methods) in three sizes of Cudrania tricuspidata leaves. For the mineral contents of the leaves, Ca was highest(17.26 mg/g.d.w.), followed by K(15.53 mg), P(2.61 mg), and Mg(1.99 mg). Ascorbic acid was found to be slightly higher(43.4 mg/100g.f.w.) in the basal parts of the medium size leaves and lowest in the whole parts(9.9 mg) of the small size leaves. Total polyphenol content was highest($1,384{\sim}1,258mg/100g.f.w.$) in the leaves, for all sizes, when extracted with 80% ethanol, followed by the stem bark(543 mg%), roots(369 mg%), stems(243 mg%), and thorns(223 g%). By determining DPPH activity, we found that antioxidant activity was higher in the ethanol extracts of the leaves than in the ethanol extracts of the thorns, stems, roots, and stem bark. While in the tea, no differences were found between the ethanol and water extracts.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1631-1635
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• 2002

In order to be good display, the ac PDP lifetime should be guaranteed over 30000 hours. Therefore, to satisfy these demands, it is need to find out main factors in ac PDP affecting the lifetime. In this paper, the characteristics of lifetime as a parameter of the MgO deposition rate conditions is investigated. MgO protective layers is fabricated by E-beam. Before measuring the lifetime we have carefully peformed high temperature evacuation and aging procedure, which is essential for providing the initial condition of our experiment. If MgO deposition rate increased, MgO film becomes dense and an adhesive power of MgO film gets better and because occurrence rate of the MgO cluster decreases, lifetime of MgO will be improved. As a result, ac PDP lifetime can be improved due to the improvement of MgO by MgO preparation conditions.