• 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.

• 한국세라믹학회지
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• 제34권9호
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• pp.941-948
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• 1997

CuCl nanocrystallites dispersed nonlinear optical silica and borosilicate glasses were fabricated by sol-gel process. CuCl powder was dissolved in TEOS(Si(OC2H5)4) and TMB((CH3O)3B), precursors of silica and borosilicate glasses, with ethanol, water and HCl, and precipitated through the heat treatment in the matrix glass. The optical properties of CuCl doped glasses were measured using the spectrophotometer at room temperature and low temperature(77K); Z1, 2 and Z3 exciton peaks from the absorption spectra, were observed at about 370 nm and 380 nm, respectively. The average radius of nanocrystallites, calculated from the blue shift of Z3 excitons, was measured according to annealing temperature and time. The precipitation temperature of CuCl nanocrystallites was decreased when boron was added to silica glass. Increase of annealing temperature and time made average radius of nanocrystallites saturated about 2 nm.

• 한국세라믹학회지
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• 제29권5호
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• pp.403-409
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• 1992

The titania membrane thickness coated on the porous alumina support by the sol-gel method was analyzed using the slipcasting model. The thickness of calcined membrane layers increased linearly from 1.3 to 3.8 ${\mu}{\textrm}{m}$ with the square root of the dipping time (4~40 min). Growth rates of the thickness of wet gels and calcined layers were well described quantitatively by the slipcasting model. Through the regression of experimental data using model equations, the permeability and the pressure drop across wet gels, and the thickness and their growth rate constants of wet gels and calcined layers could be determined. It was also known that the gellation concentration of the TiO2 sol used in this work and the porosity of wet gel layes were 25 mol/ι and 0.53, respectively.

• 한국응용과학기술학회지
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• 제17권2호
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• pp.144-148
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• 2000

A modification of the sol-gel method to obtain phase pure superconducting oxides is described. The method starts from organic salts of yttrium, barium and copper, such as acetates, and avoids the sudden and uncontrollable decomposition of the organic fraction which occurs if nitrates are used as starting materials. The aqueous solution obtained with citric acid in an alkaline medium is concentrated under vacuum. The solid so prepared is decomposed at about $300^{\circ}C$ thus giving an oxide precursor containing well dispersed yttrium, barium and copper. Pyrolysis at 850 - $920^{\circ}C$ followed by oxygen annealing gives the superconducting orthorhombic 123 phase. The results of TGA/DTA of the precursor, as well as XRD, electrical and magnetic property measurements on the pyrolysis products are presented and discussed.

• 한국광학회지
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• 제11권4호
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• pp.255-260
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• 2000

유기 금속화합물을 출발물질로 이용하는 졸-겔 방법으로 균열이 없는 유기-무기 복합 실리카 박막을 제작하였으며, 코팅방법, 조성비, prebake, postbake 온도 등의 제작조건에 따른 박막의 두께 및 굴절률의 변화를 체계적으로 조사하여 재현성 있는 제작조건을 확립하였다. 특히 광개시제를 첨가하였을 때 자외선 노광량에 따른 광학적 성질변화를 세 가지 광개시제에 대하여 측정, 비교하였다. 또한 졸-겔 박막으로 다중모드 간섭을 이용한 광 파워 분배기를 제작하여 광소자로의 응용 가능성을 살펴보았다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1146-1149
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• 2006

In this study, nanocomposite layer composed of PMMA-co-MMA and $TiO_2$ was prepared by sol-gel process using TTIP as a precursor and was utilized as a gate insulator of OTFTs. The composite insulator provides the lower threshold voltage and the enhanced sub threshold slope of OTFTs mainly due to its higher dielectric constant than that of the bare PMMA-co-MMA. Consequently, it is demonstrated that the sol-gel process can open an interesting direction for the fabrication of high-performance OTFTs, and contribute for OTFTs to be feasible for real applications.

• Transactions on Electrical and Electronic Materials
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• 제1권1호
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• pp.17-21
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• 2000

In order to investigate the dependence of a content in lead lanthanum titanate (PLT) films and heat treatment, sol-gel process has been used. Four types of PLT thin films with the chemical formula, Pb$\_$1-x/ La$\_$x/Ti$\_$1-x/4/O$_3$(X=18, 21, 24 and 28 mole %) have been fabricated on Pt/Ti/SiO$_2$/Si multi-layers and ITO/glass substrates, The post-annealing temperature in the range of 400~700 $\^{C}$ is applied for the formation of perovskite structure in PLT films. The structureal, electrical and optical properties of PLT film with the addition of La content are estimated. The films orientation and surface structure of films are studied by XRD (X-ray diffraction) and SEM(scanning electron microscopy). The P-E hysteresis loop become narrower with increasing La content. The average transmittance of the films is about 80%.

• Carbon letters
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• 제10권2호
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• pp.123-130
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• 2009

Multi-elements doped $TiO_2$ was prepared as a new photocatalyst in order to decrease the band gap of $TiO_2$ by sol-gel process which can provide the large active sites of $TiO_2$. Multi-elements were doped by using a single precursor, tetraethylammonium tetrafluoroborate (TEATFB). By the benefit of large specific surface area of $TiO_2$ prepared by sol-gel process, catalysts showed initial fast removal of dye. The photoactivity showed that the doped catalysts significantly promote the light reactivity than undoped $TiO_2$. The commendable photoactivity of prepared catalysts is predominantly attributable to the doping of anions which may reduce the band gap.

• 한국응용과학기술학회지
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• 제20권4호
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• pp.346-352
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• 2003

BaTiO$_3$, powders were prepared by sol-gel process from different aging time and reaction temperature. Particle shape, size and crystal structure of prepared $BaTiO_3$ powders were analyzed by SEM, XRD and FT-IR. Effect of aging time alternation didn't particularly show up. Spherical nano-sized $BaTiO_3$ powders were obtained from condition more than reaction temperature $55^{\circ}C$, and obtained sintered $BaTiO_3$ powders of tetragonal phase from heat-treatment at $1,100^{\circ}C$.

• 한국세라믹학회지
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• 제37권10호
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• pp.981-986
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• 2000

Er(NO$_3$)$_3$.5$H_2O$, Mn($CH_3$$CO_2$)$_2$.4$H_2O$를 출발원료로 사용하여 졸-겔법으로 제조한 ErMnO$_3$박막의 열처리 온도 및 기판 배향성에 따른 박막 배향성과 누설 전류 특성에 관하여 연구하였다. ErMnO$_3$박막은 75$0^{\circ}C$ 이하의 온도에서 1시간 열처리 시비정질상태였으나, 78$0^{\circ}C$ 이상의 온도에서 hexagonal pahse인 ErMnO$_3$로 결정화되었다. 열처리 온도가 증가할수록 기판 배향성과 무관하게 모든 방향으로 결정이 성장함을 알 수 있었다. 결정화 정도와 결정 성장 축에 따라 누설 전류 값이 변화함을 알 수 있었고, 80$0^{\circ}C$에서 열처리한 시편에서는 누설 전류 변화가 비선형적인 경향으로 증가하였으며, $10^{-5}$ A/$ extrm{cm}^2$ 이하로 유지되었다.