• 반도체디스플레이기술학회지
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• 제6권4호
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• pp.33-38
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• 2007

Quartz glass panel was prepared by a colloidal silica through the heat-treatment only without any additives in wet-chemical method. This colloidal silica used in slurry process has the uniform distribution of particle size and lower cost. The results show that 6N as a degree of purity and the 86 percentage of violet transmittance in 1mm thickness. AFM(Atomic Force Microscopy) pattern shows that the surface roughness are less than lnm. Also, we investigated the characteristic of quartz panel according to the concentration and distribution of hydroxyl group, viscosity and thermal expansion coefficient.

• 한국세라믹학회지
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• 제25권6호
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• pp.655-664
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• 1988

As a part of study to establish the industrial process for manufacturing high purity alumina powder which is largely used as fine ceramics, an adsorption method using a silica-containing material which can absorb to eliminate a major impurity, Na in aluminum hydroxide as a raw material has been studied. It is confirmed that the primary property of powder such as the particle size of raw material and that of silica-containing material plays a great important role in the purification process.

• 한국세라믹학회지
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• 제55권6호
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• pp.562-569
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• 2018

We propose an economic and facile method for the preparation of silica nanoparticles through a two-step process utilizing chlorosilane residues. Mixed chlorosilane residue was alcoholized with absolute ethanol as a first step to form tetraethoxysilane (TEOS). The TEOS was then utilized as a silicon source to synthesize silica nanoparticles in a sol-gel method. The alcoholysis process was designed and optimized utilizing the Taguchi experimental design method and the yield of TEOS was as high as 82.2% under optimal synthetic conditions. Similarly, the Taguchi method was also utilized to study the effects of synthesis factors on the particle size of silica nanoparticles. The results of statistical analysis indicate that the concentration of ammonia has a greater influence on particle size compared to the mass fractions of TEOS and polyethylene glycol (4.6% and 9.7%). The purity of the silica particles synthesized in our experiments is high, but the specific surface area and pore volume are small.

• Nuclear Engineering and Technology
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• 제38권5호
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• pp.423-426
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• 2006

A developed neutron activation analysis(NAA) and gamma-spectrometry were applied to improve the analytical sensitivity and precision of impurities in electronic-circuit raw materials. It is well known that soft errors in high precision electronic circuits can be induced by alpha particles emitted from naturally occurring radioactive impurities such as U and Th. As electronic circuits have recently become smaller in dimension and higher in density, these alpha-particle emitting radioactive impurities must be strictly controlled. Therefore, new NAA methods have been established using a HTS(Hydraulic Transfer System) irradiation facility and a background reduction method. For eliminating or stabilizing fluctuated background caused by Rn-222 and its progeny nuclides in air, a nitrogen purging system is used. Using the developed NAA and gamma-spectrometry, ultra trace amounts of U(0.1ng/g) and Th(0.01ng/g) in an alumina ball and high purity silica used for an epoxy molding compound (EMC) could be determined.

• 한국세라믹학회지
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• 제45권2호
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• pp.87-89
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• 2008

A nano structured silica aerogel thin film was manufactured from inexpensive sodium silicate (water glass) using an ambient pressure drying method. High purity silicic sol was prepared by passing a water glass solution through an ion exchange resin, and the gel films were prepared on a modified glass substrate via dip coating. The dip coating conditions, such as coating time and solvent, were optimized. The optical and physical properties of the obtained silica aerogel thin film were characterized using a UV-visable spectrometer and a scanning electron microscope.

• Journal of Ceramic Processing Research
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• 제20권spc1호
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• pp.109-112
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• 2019

γ-dicalcium silicate(γ-C2S) is known as a polymorphism of belite. Due to its high CO2 fixed capacity and the low CO2 emission production process, γ-C2S has attracted more and more attention of researchers. For the further development of application of γ-C2S in building construction industry. In this study, we aim to investigate the method for synthesizing high purity of γ-C2S. The influence of different raw materials and calcination temperatures on the purity of γ-C2S was also evaluated. Several Ca bearing materials were selected as the calcium source, the materials which' s main component is SiO2 were used as the silicon source. Raw materials were mixed and were calcined under different temperatures. The results reveal that the highest purity could be obtained using Ca(OH)2 and SiO2 powder as raw materials. And for the practical application, a relatively economic synthesis method using natural mineral materials- limestone and silica sand as raw materials was developed, by this method, the purity of the synthetic γ-C2S was 77.6%.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.78-83
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• 2009

In general, Light-hardening polymer was used UV nanoimprint technology. A light-hardening polymer was had the problem of poor hardness, durability. In order to overcome the problem of polymer, inter change optical glass. However glass is very manufacture and a lowering of standars transmittance. In order to glass recover was necessary polishing process. The process is magnetorheological fluids polishing. MR polishing has been developed as a new precision finishing technique to obtain a fine surface. Hence, Magnetorheological fluids has been used for micro polishing to get micro parts. This polishing process guarantees high polishing quality by controlling the fluid density electrically. The applied material in experiments is fused silica glass. Fused silica glass is widely used in the optical field because of high degree of purity. For MR polishing experiments, MR fluid was composed with DI-water, carbonyl iron and nano slurry ceria. The wheel speed and electric current were chosen as the variables for analyzing the characteristics of MR polishing process. Outstanding surface roughness of Ra=1.58nm was obtained on the fused silica glass specimen. And originally glass transmittance was recover on the fused silica glass.

• 공업화학
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• 제7권5호
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• pp.823-831
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• 1996

본 연구는 [$H_2O$]/[TEOS]=1.7에서 산촉매를 첨가한 부분가수분해를 행하여 졸을 합성하였다. 최적의 방사성을 갖는 졸을 결정하기 위하여 부분가수분해에 의하여 합성된 졸을 trimethylsilylation하여 안정화시킨 후에 반응시간에 따르는 분자량과 점도의 변화를 관찰하였다. 최적조건하에서 제조된 졸용액에서 용매를 제거한 후 겔섬유를 제조하였고 이를 $1,000^{\circ}C$에서 열처리하여 실리카섬유를 제조하였다. 제조된 섬유는 단면적이 원형이며 인장강도는 $83{\pm}20kg/mm^2$이었고, 순도는 약 99.997%이었다.

• 자원리싸이클링
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• 제26권4호
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• pp.19-25
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• 2017

금속실리콘을 제조하는 방법에는 탄소환원법, 플라즈마환원법, 테르밋반응 등이 있다. 상업용 금속실리콘을 대량 생산하는 방법으로 탄소환원법에 의한 아크전기로가 일반적으로 많이 사용되고 있다. 아크전기로를 이용한 생산시스템이 극복해야 할 문제로는 제조원가 중 전력비 비율이 30%를 차지할 정도로 높은 전기에너지 비용과 환경방지 시설구축 및 유지관리비용이다. 이러한 이유로 국내에서는 아직 아크전기로를 이용한 생산시스템이 상용화 제조시스템으로 구축되지 못하고 있다. 기업 및 연구기관에서 탄소환원법의 아크전기로를 이용하여 최적 생산시스템을 연구하고 있다. 세 가지 유형의 이산화규소를 테르밋반응을 통하여 순도변화를 알 수 있었다. 그리고 실험분석에서 테르밋반응을 사용하여 이산화규소 순도로 금속실리콘 순도 변화를 분석하였다. 이산화규소 순도와 금속실리콘 순도는 밀접한 관계가 있음을 알 수 있었다.

• 자원리싸이클링
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• 제13권2호
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• pp.33-38
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• 2004

제철산업에서 발생되는 고로수재슬래그로부터 고순도 질산칼슘을 회수할 수 있는 독창적인 자원화 공정을 위한 개념과 실험결과를 수록하였다. 먼저 고로수재슬래그를 질산과 반응시킨 후, 불용성의 실리카를 분리하였고, 생석회를 첨가하여 여액의 pH를 6∼8범위로 조절하여 Fe, Al, Mg등의 불순물을 침전, 여과 분리시켰으며, 고농도의 질산칼슘여액을 결정화시킴으로써 비료 등으로 활용될 수 있는 순도가 98% 이상인 고부가 가치성 질산칼슘 4수화물 결정을 회수하였다.