• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.44-45
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• 2001

실리카 마이크로 스피어는 손실이 대단히 적은 초고품위 공진기로 알려져 있다. 최근의 실험들에 의하면 실리카 마이크로 스피어는 공진기 Q 값이 $10^{9-10}$ 정도인데, 이는 현재까지 만들어진 마이크로 공진기들 중에서 가장 높은 값이다. 최근 마이크로 스피어는 저손실의 공진기로서 문턱조건이 없는 레이저 연구에 활용되고 있으며, 레이저와 좁은 공명 모드 선폭을 이용하여 레이저 주파수 안정화 및 광섬유 결합기 등에 활용되고 있다. 또한 Cavity-QED 연구와 Cavity-QED 효과를 이용한 소수의 양자점 레어저 연구에도 활용도고 있다. (중략)략)

• Resources Recycling
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• v.30 no.2
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• pp.68-74
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• 2021

This study investigated formaldehyde (HCHO) removal by preparing porous supports using domestic low-grade silica coated with Co-ZSM5 and Cu-ZSM5 as the catalysts. First, the sample of the raw material for the support contained 90% silica with quartz crystal phase, which was confirmed as low-grade silica. According to Energy-dispersive X-ray spectroscopy (EDS) and Fourier-transform infrared spectroscopy (FT-IR) analyses, the catalysts, Co-ZSM5 and Cu-ZSM5, were successfully coated on the surface of the porous silica supports. During the removal test of HCHO using the prepared Co-ZSM5 and Cu-ZSM5 coated beads, depending on the reaction temperature, the Co-ZSM5 coated beads exhibited higher removal efficiencies (>97%) than the Cu-ZSM5 beads at 200 ℃. The higher efficiency of the Co-ZSM5 coating may be attributed to its superior surface activity properties (BET surface area and pore volume) that lead to the favorable HCHO decomposition. Therefore, Co-ZSM5 was determined to be the suitable catalyst for removing HCHO as a coating on a porous support fabricated using domestic low-grade silica.

• Korean Journal of Materials Research
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• v.8 no.10
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• pp.879-883
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• 1998

In the vacuum casting process for superalloys, molten metal are poured into the heated ceramic mold up to $1000^{\circ}C~1700^{\circ}C$. The mold has to have the high temperature strength during casting and made by hlgh purity alumina. In this sturdy, the mold was made by low purity alumina and changed silica contents intended to have high strength The 7.7wt.% SiOz specimens have 10- 55% higher strength than others in room and high temp. Therefore, the cast mold has been developed in this study for single crystal vacuum cast by controlling the ratio of fused alumina and colloidal silica which are used commercially for conventional casting in industries.