• Proceedings of the Korean Ceranic Society Conference
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• 2000.10a
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• pp.165.2-165
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• 2000

• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.160-160
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• 2005

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.124-124
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• 2014

Plasma Electrolytic Oxidation(PEO)를 적용하여 두께 $120{\mu}m$의 알루미늄 판에 $Al_2O_3$ 산화피막을 형성하였다. 전해액의 주성분 KOH 와 $Na_2SiO_3$에 $Na_3P_2O_7$, $H_3PO_4$의 첨가제를 넣어 산화피막을 분석하였다. 첨가제 $Na_3P_2O_7$ 을 넣었을 때 치밀한 구조를 갖는 산화피막이 형성됨을 알 수 있었다. 특히 KOH, $Na_2SiO_3$, $Na_3P_2O_7$의 비율이 5:5:2 일때 가장 치밀하고 균질한 구조를 갖는 산화피막이 형성되었다.

• Journal of the Korean Ceramic Society
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• v.49 no.2
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• pp.146-150
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• 2012

The effects of $Al_2O_3$ on the crystallization behavior of glass compositions in the $Na_2O$-CaO-$SiO_2$ system were investigated by differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The effect of $Al_2O_3$ content on the mechanical properties, density, phase formation, and microstructures of $Na_2O$-CaO-$P_2O_5$-$SiO_2$ glass ceramics were studied. The thermal parameters of each glass were studied by DTA. The density of the glass ceramic samples was measured by Archimedes' method. It was found that the glass-ceramic containing 2.0 molar percent $Al_2O_3$ had desirable sintering behavior and reached an acceptable density. Phase investigation and micro-structural analysis were performed by XRD and SEM, respectively.

• Bulletin of the Korean Chemical Society
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• v.31 no.10
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• pp.2961-2966
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• 2010

Reduction of carbonyl compounds such as aldehydes, ketones, $\alpha,\beta$-unsaturated enals and enones, $\alpha$-diketones and acyloins was carried out readily with $NaBH_3CN$ in the presence of wet $SiO_2$ as a neutral media. The reactions were performed at solvent-free conditions in oil bath (70 - $80^{\circ}C$) or under microwave irradiation (240 W) to give the product alcohols in high to excellent yields. Regioselective 1,2-reduction of conjugated carbonyl compounds took place in a perfect selectivity without any side product formation.

• Journal of the Korean Ceramic Society
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• v.20 no.2
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• pp.147-152
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• 1983

For $Na_2O-BaO-SiO_2$ system glass the pelletizing conditions of the disk type equipment were investigated. The effects of the pelletized batch on melting were also examined. Through the experiment the optimum conditions for pelletizing the batch were found as follows. Revolving speed of the pan 30rpm pan angle 40-35 degree Water content 12-13% Drying temperature $200^{\circ}C$ Preheating temperature $650^{\circ}C$ The molten glass of the pelletized batch was refined better than that of the loose batch.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.4
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• pp.328-331
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• 1991

LiF(Mg,Cu,Na,Si) 형광체의 ${\gamma}$선과 $\beta$선에 대한 TSEE 특성을 조사하였다. 상(60)Co ${\gamma}$선에 대한 감도는 약 450 counts/mR이었고, 여러 가지 $\beta$선에 대한 TSEE 에너지 의존성은 $\beta$입자의 평균에너지 0.02MeV에서 0.8MeV 사이에서 $\pm$10%이었다. 그리고 제작된 형광체 앞면에 7mg.cm 상(-2)의 인체 등가물질을 두 면 입사 $\beta$입자의 에너지에 무관하게 피부 흡수 선량을 측정할 수 있었다.

• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.577-581
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• 2011

Silicon nanoparticles have attracted a great deal of scientific interests due to its intense photoluminescence in the visible spectral region and its potential applications in biological fluorescence maker, RGB (red, green, blue) display, photonics and photovoltaics etc. Practical applications making use of optical and physicochemical properties of Si nanoparticles requires an efficient synthetic method which allows easy modulation of their size, size distribution as well as surface functionalities etc. In this study, a one-pot solution reduction scheme is attempted to prepare alkyl-terminated Si nanoparticles (<10 nm) with Si precursors, (Octyl)$SiCl_3$ or mixture of (Octyl)$SiCl_3$ and $SiCl_4$, containing alkyl-groups using Na(naphthalide) as reducing agent. The surface capping of Si nanoparticles with octyl-groups as well as Si nanoparticle formation was achieved in one-pot reaction. The hexane soluble Si nanoparticles with octyl-termination were in the range of 2-10 nm by TEM and some oxide groups (Si-O-Si) was present on the surface by EDS/FTIR analyses. The optical properties of Si nanoparticles measured by UV-vis and PL evidenced that photoluminescent Si nanoparticles with alkyl-termination was successfully synthesized by solution reduction of alkyl-containing Si precursors in one-pot reaction.

• Journal of the Korean Ceramic Society
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• v.21 no.3
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• pp.217-220
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• 1984

The leaching of Na-fluor-tetrasilicic mica $NaMg_{2.5}(Si_4O_{10})F_2$ (Na-TSM) in the deionized water was investigated by measuring the pH released Na and Mg contents in the suspension. According to the results it was found that $Na^+$ ions of interlayer in the Na-TSM were easily replaced by $H^+$ ions from the deionized water because $Na^+$ ions of I were repidly diffused to form a large hydrated electric double layer in the suspension.

• Journal of the Korean Ceramic Society
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• v.49 no.3
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• pp.241-246
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• 2012

Physical properties of plasma electrolytic oxidized layers of 8 different kinds of Al alloys, A-1100, A-2024, A-5052, A-6061, A-6063, A-7075, ACD-7B and ACD-12 were investigated. The electrolyte for plasma electrolytic oxidation was mixture of distilled water, $Na_2P_2O_7$, KOH and some metal salts. Growth rate of oxide layer was slower in $Na_2P_2O_7$ electrolyte system than in $Na_2SiO_3$ system, and Ra50 surface roughness of oxidized layer was below $1.2{\mu}m$. Surface hardness in $Na_2P_2O_7$ electrolyte system is higher than in $Na_2SiO_3$ system, and roughness was lower in $Na_2P_2O_7$ electrolyte system than in $Na_2SiO_3$ system.