• Bulletin of the Korean Chemical Society
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• v.24 no.4
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• pp.499-503
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• 2003

Encapsulation of L-ascorbic acid (vitamin C) within a bio-compatible layered inorganic material was achieved by coprecipitation reaction, in which the layered inorganic lattice and its intercalate of vitamin C are simultaneously formed. The nano-meter sized powders of vitamin C intercalate thus prepared was again encapsulated with silica nano-sol to form a nanoporous shell structure. This ternary nanohybrid of vitamin Clayered inorganic core-$SiO_2$ shell exhibited an enhanced storage stability and a sustained releasing of vitamin C. Furthermore, the nano-encapsulation of vitamin C with inorganic mineral was very helpful in delivering vitamin C molecules into skin through stratum corneum, facilitating transdermal penetration of vitamin C in topical application.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.106-106
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• 2003

최근 집적형 광소자, 레이저 재료, 자료 저장 또는 통신 기술부문에서 제어된 광학적 성질을 갖는 유기-무기 나노 복합체를 만드는 연구가 많은 관심과 주목을 받고 있다. 유기물인 PEG는 대다수의 금속염을 고정시키는 용매 역할을 하는 polymer로써 액체와 같은 특징을 나타내며 무기물인 silica의 network는 순수한 PEG 시스템보다 좋은 기계적 물성을 나타내며, 투명한 물질을 얻을 수 있게 해 준다. 이에 본 연구에서는 SiO2-PEG의 matrix에 우수한 광학적 성질을 지닌 europium을 doping하여 유기-무기 나노 복합막을 합성하여 europium의 농도와 PEG 분자량에 따른 구조적 및 광학적 성질을 알아보고자 한다.

• Advances in environmental research
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• v.6 no.4
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• pp.255-264
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• 2017

This work investigated the use of sugarcane bagasse ash (SCBA) generated by an energy cogeneration process in sugarcane mill as an alternative raw material in soil-cement brick. The SCBA obtained from a sugarcane mill located in southeastern Brazil was characterized with respect to its chemical composition, organic matter content, X-ray diffraction, plasticity, and pozzolonic activity. Soil-cement bricks were prepared by pressing and curing. Later, they were tested to determine technical properties (e.g., volumetric shrinkage, apparent density, water absorption, and compressive strength), present crystalline phases, and microstructural evolution. It was found that the SCBA contains appreciable amounts of silica ($SiO_2$) and organic matter. The results showed that the SCBA could be used in soil-cement bricks, in the range up to 30 wt.%, as a partial replacement for Portland cement. These results suggest that the SCBA could be valorized for manufacturing low-cost soil-cement bricks.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.171-174
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• 1995

Space charge formation in epoxy loaded with silica and calcium carbonate has been studied. The epoxy itself showed almost no charge at up to 40 kV/mm. The addition of fillers such as SiO$_2$and CaCO$_3$resulted in homocharge formation, which was attributed to the interfacial trapping of injected charge at epoxy/filler interfaces. The amount of charge showed a maximum at 20-40 parts per hundred resin above which the charge decreased gradually. This was tentatively attributed to the enhanced interconection of charge transport path by an increased filler content

• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.871-874
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• 2014

Monodispersed carbon nanospheres (CNSs) were fabricated by a novel method and their structural properties were investigated. CNSs were prepared by the pyrolysis of nanospherical polystyrenes (PS). With the coating of $SiO_2$ shell, PS particles were effectively separated during pyrolysis process which resulted to CNSs with an average diameter of 40 nm. Moreover, CNSs could be crosslinked with each other through the bondings between the functional groups on their surfaces. Morphology of the fabricated carbon spheres and their crosslinked form were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and fourier transform infrared spectroscopy (FT-IR).

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.52-57
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• 1999

The aimed of this study is to analyze the qualities of foundry waste sand and the basic physic of the concrete mixed with the foundry waste sand, as a way of study for reusing the foundry waste sand disused in the foundry as the fine aggregate for concrete. According to the experimental results, the foundry waste sand is composed of silica ore whose main ingredient is SiO2 and doesn't produce harmful objects of hydration reaction, and the fluidity of concrete shows a decline with the increase of replacement ratio of foundry waste sand, and the compress strength, the tensile strength, the elastic modulus of concrete containing foundry waste sand are improved at the replacement rate of 25%.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.155-155
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• 1999

반도체 소자의 초고집적화와 고속화에 따라 최소 선폭이 급격히 줄어듬에 따라 현재 사용되고 있는 다층금속배선의 층간절연막 0.18$\mu\textrm{m}$ 급 이상의 소자에 적용할 경우 기생정전용량이 증가하여 신호의 지연 및 금속배선간에 상호간섭현상으로 반도체 소자의 동작에 심각한 문제가 대두되고 있다. 이러한 물제를 해결하기 위하여 nonoporous silica, fluorinated amorphous carbon, polyimides, poly(arylene)ether, parylene, AF4, poly(tetrafluoroethylene), divinyl siloxane bisbenzocyclobutene, Silk, 그리고 유무기 hybrid nanofoam 등이 저유전물질로 각광을 받고 있으며, 여기에 대한 연구가 우리나라를 비롯하여 미국, 일본 등에서 많은 연구가 이루어지고 있다. 따라서 본 연구에서는 2003년에 개발될 0.13$\mu\textrm{m}$급 이상의 차세대 반도체 소자에 적용될 수 있는 저유전물질 개발현황과 이들 물질 중 4GDRAM 급이상의 소자에 적용가능성이 가장 높은 유무기 hybrid nanofoam, a-C:F와 C:F-SiO2 박막에 대한 특성에 대하여 소개하고자 한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.18-22
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• 2002

CMP(chemical mechanical polishing) process has attracted as an essential technology of multilevel interconnection. However, the COO(cost of ownership) is very high, because of high consumable cost. Especially, among the consumables, slurry dominates more than 40%. So, we focused that it has how to reduce the consumption of raw slurry. In this paper, we presented the pH changes of diluted slurry and pH control as a function of KOH contents. Also, the removal rates of slurry with different dilution ratio was investigated. Finally, CMP the characteristics as a function of silica($SiO_2$) abrasive contents were discussed.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.156-157
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• 2000

낮은 도핑의 silicon은 광통신에서 사용하는 1.3 및 1.55 um의 광파장 영역에서 0.01dB/cm 이하의 낮은 흡수 손실을 가짐으로 인해, core 층으로 silicon을 사용하며 상부 및 하부 cladding 층으로 SiO$_2$와 같은 유전체 박막 구조를 갖는 SOI (Silicon on Insulator)를 사용한 수동광소자에 대한 연구가 1990년대부터 진행되고 있다. 또한 silicon의 특성상 SOI는strain에 의한 영향이 낮고, 광학적 비등방성이 적어서 polymer 및 silica를 이용한 광소자에 비해 편광의존도가 낮은 광소자를 구현할 수 있는 장점이 있다. 현재까지 연구되어온 SOI 수동광소자의 연구결과는 TE/TM 편광차에 따른 채널분리도가 약 0.04nm, 누화특성이 23dB 인 8채널 AWG의 연구결과가 있었으며, 스위칭시간 < 1msec, 소광비 17 dB의 광결합기와 마하젠더가 혼합된 광변조기 및 Bookham사에서 개발한 RX/TX 양방향 송수신 광모듈에 적용된 1.3/l.55 um 파장선택적 분리기, Silicon-CMOS 증폭기와 집적화된 4channel 광다중 수신기등에 대한 연구결과가 있었다. (중략)

• Transactions on Electrical and Electronic Materials
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• v.5 no.6
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• pp.233-236
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• 2004

Copper metallization has been used in high-speed logic ULSI devices instead of the conventional aluminum alloy metallization. One of the key issues in copper CMP is the development of slurries that can provide high removal rates. In this study, the effects of slurry chemicals and pH for slurry dispersion stability on Cu CMP process characteristics have been performed. The experiments of copper slurries containing each different alumina and colloidal silica particles were evaluated for their selectivity of copper to TaN and $SiO_{2}$ films. Furthermore, the stability of copper slurries and pH are important parameters in many industries due to problems that can arise as a result of particle settling. So, it was also observed about several variables with various pH.