• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
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• pp.107-110
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• 2002

The optical memory devices of BST thin films to composite $(Ba_{0.7}\;Sr_{0.3})TiO_{3}$ using sol-gel method were fabricated by changing of the depositing layer number on $Pt/Ti/SiO_{2}/Si$ substrate. The structural properties of optical memory devices to be ferroelectric was investigated by fractal analysis and 3-dimension image processing. The thickness of BST thin films at each coating numbers 3, 4 and 5 times was $2500[\AA]$, $3500[\AA]$ and $3800[\AA]$. BST thin films exhibited the most pronounced grain growth. The surface morphology image was roughness with coating numbers. The thin films increasing with coating numbers shows a more textured and complex configuration.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 추계학술대회 논문집 학회본부
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• pp.143-149
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• 1990

A sol-gel processing of $YBa_2Cu_3O_{7-x}$ superconductor using metal nitrate salts and sodium hydroxide as the starting materials has been investigated because of the need to produce pure, hompgeneous superconducting materials. Since the precipitation of barium hydroxides can be obtained only at high basicities, the process has to be carried out Ca. pH 13 to get the simultaneous coprecipitation with the other metal hydroxides. The involved reaction mechanisms were investigated and intermediate and final products were characterized by means of thermogravimetric analysis(TGA), infra-red(IR) spectroscopy, X-ray diffraction(XRD) analysis, scanning electron microscopy(SEM), thermal mechanical analysis(TMA) and electrical measurement.

• 한국세라믹학회지
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• 제32권2호
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• pp.197-208
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• 1995

${\gamma}$-LiAlO2 fibers for fiber reinforced molten carbonate fuel cell (MCFC) matrix have been produced from LiAlO2 complex polymeric sols using the sol-gel process. The stable and spinnable LiAlO2 sols could be synthesized by mixing LiNO3 alcohol solutions in aluminum complex polymeric sols prepared through the condensationpolymerization reaction of 1 more of aluminum tri-sec-butoxide with 0.55 mole of mixed chelates (mole ratio of acetylaceton/triethanolamine=0.25/0.3). It was found that the viscosity range for fiber-spinning should be higher than 30 poise. The defect-free flexible ${\gamma}$-LiAlO2 fibers with the average tensile strength of 350 MPa could be obtained when the spinned fibers were heat-treated to 120$0^{\circ}C$ on the specified heating schedule after dried at room temperature.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.220-220
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• 2003

The microencapsulation of droplets or particles within a solid shell leads to the formation of core-shell particles. Microencapsulation provides protection and controlled release of core materials such as drugs, vitamins, enzymes, perfumes, and the like. Such particles have, therefore, found a diverse range of applications in the pharmaceutical, agricultural, cosmetic, and food industries. UV absorbers are widely used for cosmetics to screen out ultra violet (UV) rays which have side effects on human skin. The absorbers are made generally from synthetic organic compounds, which can stimulate the human skins to develop allergic phenomena.

• 한국세라믹학회지
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• 제30권3호
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• pp.189-198
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• 1993

A new pressurized sol-gel coating technique forming membrane layers inside pores of the porous support by the simple operation has been developed. Crack-free and reproducible nanoparticulate silica membranes supported on the porous $\alpha$-alumina tube are synthesized by pressurized coating at 600kPa for 2hr. The pore radius and N2 gas permiability at the room temperature of silica membrane layers are 8$\AA$ and 7.0$\times$10-7mol/$m^2$.s.Pa, respectively. The mechanism of N2 gas transfer through synthesized membrane layers is the perfect Knudeen flow, and the thermal stability of the silica composite membranes is excellent upto 40$0^{\circ}C$.

• 한국응용과학기술학회지
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• 제24권3호
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• pp.246-252
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• 2007

$BaTiO_3$ powders were prepared by sol-gel method from different concentration of KOH aqueous solution and Ba/Ti molar ratio. Particle shape, size and crystal structure of prepared $BaTiO_3$ powders were analyzed by SEM, XRD, and FT-IR. As the result of KOH concentration changing, spherical particles were obtained by condition more than 3 M and particle size decreased as concentration increasing. Different appearance showed between dried and sintered powders against changing of Ba/Ti molar ratio. In case of dried powders, the crystallinity decreased as molar ratio increasing. On the other hand, increased as molar ratio increasing in case of sintered powders.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.137-137
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• 2006

본 연구에서는 FeRAM 적용을 위한 BLT 캐패시터 제조시 CMP 공정압력 변화에 따른 Leakage Current의 특성에 대해서 연구하였다. 6-inch Pt/Ti/Si 웨이퍼를 사용하였으며, 기판 위에 졸-겔(Sol-Gel)법으로 모든 BLT를 스핀코팅을 이용하여 증착시켰다. 증착된 BLT는 $200^{\circ}C$에서 기본 열처리 후 다시 $700^{\circ}C$에서 후속 열처리 하였다. 이러한 과정을 두번 반복하였며, FeRAM 적용을 위한 BLT 캐패시터 제조시 CMP 공정 중 압력 변화를 달리하여 BLT 캐패시터를 제조한 후 Leakage Current를 측정하였다. 결과적으로 CMP 공정 시 압력의 증가에 따라 Leakage Current값이 증가하였다. CMP 공정시 압력과 박막 표면의 스크레치로 증가로 인해 Leakage Current의 증가하였다고 판단된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.299-301
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• 1989

This study presents a method of preparing $YBa_2Cu_3O_{7-x}$ ceramic and chlorine doping in it for the purpose of Jc enhancement us ins sol-gel process.Tetramethylammonium-hydroxide and pottasium carbonate solution were added to the aqueous solution of Yttrium nitrate, Barium chloride and Copper nitrate for pH control as well as forming hydroxy-carbonate precipitation. Instead of Barium nitrate, Barium chloride was used for doping chloride impurities in the specimen. The resulted materal showed good high Tc-superconductivity after calcination. Tc and Jc value are 92 K and 120.8 $A/cm^2$ respectively.

• 한국세라믹학회지
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• 제38권2호
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• pp.122-127
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• 2001

수열법으로 합성한 헥토라이트 점토(SHC), 아크릴 라텍스 및 코팅첨가제들을 배합하여 성분이 다른 수성코팅제(WBC-0, WBC-1, WBC-2) 3종류를 제조하였다. 제조한 수성코팅제(WBC)의 pH, 용액점도 및 고형분을 조사하였고, 전단력에 따른 유동성을 레오메타로 측정하였다. 또한 WBC로부터 주조된 필름의 열안정성과 투명성을 각각 TGA와 UV-VIS 분광광도계로 조사하였다. SHC가 8 phr 포함된 WBC-2는 전단력에 따라 졸과 겔의 상전이 현상, 즉 요변성을 나타내었으며 이로 인해 저장안정성이 우수하였다. 주조한 WBC-1과 WBC-2 필름의 초기분해온도와 투명성은 시판 WBC(OP-55W)의 필름보다 각각 99.6~110.2$^{\circ}C$와 20.9~21.7%의 범위로 증가하였다. 결과적으로, SHC가 함유된 WBC는 수팽윤성 점토에 의해 내열성과 용액점도의 증대효과가 나타났다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 영호남 합동 학술대회 및 춘계학술대회 논문집 센서 박막 기술교육
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• pp.31-34
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• 2006

In this study, $(Ba_{0.7}\;Sr_{0.3})TiO_3$ was coated on Pt/Ti/$SiO_2$/Si wafer by using Sol-Gel method. Coating process was repeated 3~5 times and then sintered at 750[$^{\circ}C$] for 1 hour. Each specimen was analyzed structure and electrical characteristics. In structure characteristics, EDX analyzed the samples ratio of the formation on the structural property. Thermal behavior was observed with TG-DTA and concluded that the heat-treatment of the samples was degreed 750[$^{\circ}C$]. Surface and section of thin films were observed with SEM.