• Progress in Superconductivity and Cryogenics
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• v.14 no.4
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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.

• Applied Chemistry for Engineering
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• v.25 no.4
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• pp.374-379
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• 2014

After completing deacidification process and evacuating rest of solvent, white fine particles of MgO are found on the surface of archival materials, such as books and documents. When MgO particles remain on the surface of archives, instead of being well dispersed and absorbed into cellulose fiber of archives, such white fine particles are found. These particles have raised concerns for employees' deacidification environment and their health; however, the concerns have not been addressed. To find the cause of white fine particles on the surface of archives after deacidification process and to propose the its solution, an acidic paper and wood free paper were applied with deacidifying chemicals. We analyzed the domestic and abroad deacidifying chemicals' physical properties and conducted deacidifcation processes to find effects of different contents and sizes of MgO on white fine particles. When the size of MgO particle was 847 nm, there was significantly less amount of white fine particles on the surface of archival materials. This means that the size of MgO particle plays a significant role in producing white fine particles on the surface of archives.

• Proceedings of the KIEE Conference
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• 2002.06a
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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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• v.9 no.3
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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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• 2007.08b
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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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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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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• v.20 no.2
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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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• v.12 no.1
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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.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.5
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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.

• Proceedings of the KIEE Conference
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• 2002.07c
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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.