• 보존과학연구
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• s.21
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• pp.57-75
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• 2000

We performed the scientific analysis through composition analysis, micro-structure investigation, melting point and hardness test to the glass beads excavated at Naesanri in Gosung. Through this investigation, we could examine closely the characterization of raw materials and manufacture technique As a result of micro-structure investigation of glass beads, it appeared that the bubbles in glass beads have remained. Coloring agents of yellow glass bead was remained to the shape of inclusion. And on observing the transparent solid particle, we can know that these do not melt the raw materials because of low melting temperature of a crucible. The result of composition analysis of all glass beads using ICP, these were classified as $Na_2O_2$-$SiO_2$ type of glass. Also, these added to $AI_2O_3$ to improve the durability. The value of Vickers hardness of glass beads appeared the HV 490-530. The HV 1,440 of the transparent solid particle was much more than that of inner glass bead. This means that raw materials do not melt because of a low melting temperature of a crucible. The result of melting temperature analysis of glass beads using DSC/TGA, it was measured about $1,250^{\circ}C$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.4
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• pp.190-195
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• 2009

Na-tetrasilicic fluorine mica powders were synthesized by skull melting method. The staring materials having chemical composition of $Mg_3(OH)_2Si_4O_{10}:Na_2SiF_6:SiO_2=8.3:24.8:66.9$ mol% were charged into a cold crucible of 13 cm in diameter and 14cm in height and heated by R.F. generator at working frequency of 2.84 MHz. The materials were maintained for 1hr as a molten state and cooled down in the container. In this study, the specific electric resistance of mica was estimated and the columnar and plate shaped mica were synthesized.

• Journal of the Korean Ceramic Society
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• v.43 no.3 s.286
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• pp.173-176
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• 2006

${Sr_{1-x}Ba_xNb_2O_6$(SBN) have been obtained in Pt crucible by melting and cooling in air atmosphere. Some SBNs being at the bottom of the crucible are black and transparent, and the other SBNs colorless. The black SBN became to be colorless by oxidation heat treatment $1,300^{\circ}C$ for 4 h, Curie temperature is changed by colorless change of black SBN. The reason seems to be $Nb^{5+}$ oxidation of some $Nb^{4+}$ ions in SBN or effect of unknown impurities. Diffused Phase Transition (DPT) was appeared during heating and cooling process. Various sintered SBN ceramics specimen showed relaxor characteristics.

• Journal of the Korean Ceramic Society
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• v.43 no.3 s.286
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• pp.148-151
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• 2006

In order to examine the process parameters for the vitrification of Low and Intermediate Level radioactive Waste (LILW) generated from nuclear power plants, measurements of several melt properties was performed for four selected glasses containing simulated waste. Electrical conductivity and viscosity were determined at temperatures ranging from 1123 to $1673^{\circ}C$. The temperature dependences of both properties in the molten state showed a similar behavior in which their values decrease as the temperature increases. The values of the electrical conductivity and viscosity at a temperature of 1423K adopted in an induction cold crucible melter process were $0.27{\sim}0.42$ S/cm and $9.8{\sim}42$ dPas, respectively.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.4
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• pp.141-148
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• 2006

Skull melting method can be a good candidate for growing oxide single crystals with high quality and for mass production because of its low production costs and high yield through recycling of crust. In this study, rutile single crystals were frown by the skull melting method and ingot characteristics with the variation of different growth conditions has been investigated. Conditions for high quality rutile ingot growth were used for producing cold-crucible size of ${\Phi}12cm{\times}H14cm$, capacity of 3000 pF tank condenser, work frequency of 2.84 MHz, melt-dwelling time of 9hrs and growing speed of 2 mm/h.

• Journal of Mechanical Science and Technology
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• v.20 no.7
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• pp.1089-1097
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• 2006

The market demand of display devices is drastically increasing in the information technology age. The research on OLED (Organic Light Emitting Diodes) display with the luminescence in itself is being more paid attention than LCD (Liquid Crystal display) with the light source from the back. The vapor deposition process is most essential in manufacturing OLED display. The temperature distribution of the linear cell in this process is closely related to securing the uniformity of organic materials on the substrate. This work analyzed the temperature distribution depending on the intervals between the crucible and the heating band as well as on the amount of the heat flux from the heating band. Moreover, the roles of the water jacket and the configuration of the cover within the linear cell were examined through the temperature analysis for six configurations of the linear cell. Under the above temperature analysis, the variations in the intervals and the amount of the heat flux were considered to have an effect on building the uniform temperature distribution within the crucible. It is predicted that the water jacket and the adequate configuration of the cover will prevent the blowout and clogging phenomena, respectively. The results can be used as the fundamental data for designing the optimal linear cell.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.719-724
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• 2001

The objective of this investigation was to separate silicon and silica for recycling by the liquid-liquid separation technique. In the preparation of silicon (Si) single crystal, a small amount of silicon is fixed on the surface of silica (quartz, $SiO_2$) crucible. The used crucible is crushed for recycling both silicon and silica in a high purity from the mixed powder. Zeta-potential of silicon and silica are almost the same at pH higher than 3. Their separation by simple flotation is ruled out. However, their hydrophobic characteristics are different in several different organic solvent from the measurement of contact angle. Therefore, the liquid-liquid extraction is employed to separate silicon and silica. The result indicates that the organic solvent mixed with dodecyl ammonium acetate could extracted the silicon powder at high purity (97-100%) with high recovery from the silica powder in the water phase.

• Journal of Microbiology and Biotechnology
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• v.23 no.6
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• pp.779-784
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• 2013

Leptospirosis is a worldwide zoonosis of global concern caused by Leptospira interrogans. The availability of ligand libraries has facilitated the search for novel drug targets using chemogenomics approaches, compared with the traditional method of drug discovery, which is time consuming and yields few leads with little intracellular information for guiding target selection. Recent subtractive genomics studies have revealed the putative drug targets in peptidoglycan biosynthesis pathways in Leptospira interrogans. Aligand library for the murD ligase enzyme in the peptidoglycan pathway has also been identified. Our approach in this research involves screening of the pre-existing ligand library of murD with related protein family members in the putative drug target assembly in the peptidoglycan biosynthesis pathway. A chemogenomics approach has been implemented here, which involves screening of known ligands of a protein family having analogous domain architecture for identification of leads for existing druggable protein family members. By means of this approach, one murC and one murF inhibitor were identified, providing a platform for developing an anti-leptospirosis drug targeting the peptidoglycan biosynthesis pathway. Given that the peptidoglycan biosynthesis pathway is exclusive to bacteria, the in silico identified mur ligase inhibitors are expected to be broad-spectrum Gram-negative inhibitors if synthesized and tested in in vitro and in vivo assays.

• New & Renewable Energy
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• v.1 no.4 s.4
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• pp.6-11
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• 2005

본 고에서는 태양전지 모듈 원가의 60% 이상을 차지하는 실리콘 기판의 생산성을 향상시키고 그에 따라 제조단가를 저감시키기 위한 일환으로 최근 들어 일본과 프랑스를 중심으로 중점적으로 기술개발이 이루어지고 있는 EMCC법 (Electro Magnetic Continuous Casting)에 의한 다결정 실리콘 잉고트의 제조기술에 관하여 연구하였다. 특히, 태양전지급의 고순도 잉고트로 제조하기 위해 높은 용융점과 낮은 전기전도도를 갖는 실리콘의 용해 및 주조 공정이 수냉되는 cold crucible 내에서 이루어지게 됨에 따라 발생하는 종래의 EMCC법의 문제점을 해결하고자, 코일전류 및 도가니 구조 등이 Joule 가열 효과 및 pinch 효과에 미치는 영향을 체계적으로 조사하였다. 연구 결과 대용량의 전원장치나 별도의 2차 가열원을 사용하지 않고서도 실리콘 원료의 가열 및 용해 효율을 현격히 향상시키며 용탕의 전 구간에 걸쳐 전자기력을 용탕의 정수압보다 큰 상태로 유지할 수 있는 EMCC용 무접촉성 도가니의 설계기술 및 이를 활용하는 전자기연주공정기술을 확립하였으며, 그 결과 직경 5cm의 실리콘 잉고트를 1,5mm/min의 속도로 무접촉 조건에서 연속주조할 수 있었다.

• Journal of Korea Foundry Society
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• v.31 no.5
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• pp.288-292
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• 2011

In order to complement the drawbacks of quartz crucible such as fragile-like break and melt-leakage through open slit nozzle, a new PFC system has been developed using a common graphite crucible and plugging system. The u melt is fed on to the rotating a roll through slit nozzle by self-gravity. The new equipment was designed and manufactured successfully. An effort for optimizing all related parameter has been made. Then using the optimized parameters about 10 meters u foil having very thin thickness, which meets the target thickness of 130 ${\mu}m$ and enough width more than 60 mm could be made. The thickness homogeneity set improved, due to the lower eddy flowing of the melt flow the self-gravity feeding system.