• Journal of the Korean Electrochemical Society
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• v.3 no.1
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• pp.11-14
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• 2000

Transparent conducting ITO thin films have been studied and developed for the solar cell substrate or LCD substrate. ITO thin film has been mostly fabricated by high cost sputtering method. In this research, sol-gel method is applied to fabricate ITO thin film at lower cost. The research is focused on the establishment of process condition and development of precursor. Organic sol was made of indium tri-isopropoxide dissolved in ethylene glycol monoethyl ether. The hydrolysis was controled by addition of acetyl acetone. Tin(IV) chloride was added as dopant. Inorganic sol was made of indium acetate dissolve din normal propanol. Spin coating technique was applied to coat ITO on borosilicate glass. The resistivity of ITO thin film was approximately $0.01\Omega{\cdot}cm$ and the transmittance is higher than $90\%$ in a visible range.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.196-200
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• 2018

In this study, the intermediate layer in Pd-based hydrogen separation membrane was synthesized to minimize the surface roughness and defects using powder-type and sol-type metal oxides. The surface properties and gas permeation characteristics were analysed by SEM and $N_2$ gas permeation test. The coating layer composed of sol type metal oxides has smooth surface, especially the layer coated by $TiO_2$ sol has little pin holes, cracks and defects. The binary layer composed of powder type and sol type metal oxides has similar flux characteristics to a single sol type layer. The Pd-based composite membrane improved by the binary intermediate layer exhibited $0.32mol/m^2s$ of the hydrogen permeation flux with a selectivity ($H_2/N_2$) of ~10,890 at 672 K and a pressure difference of 1 bar.

• Journal of the Korean Mathematical Society
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• v.52 no.6
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• pp.1209-1251
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• 2015

The purpose of this paper is to classify all compact manifolds modeled on the 4-dimensional solvable Lie group $Sol_1^4$, and more generally, the crystallographic groups of $Sol_1^4$. The maximal compact subgroup of Isom($Sol_1^4$) is $D_4={\mathbb{Z}}_4{\rtimes}{\mathbb{Z}}_2$. We shall exhibit an infra-solvmanifold of $Sol_1^4$ whose holonomy is $D_4$. This implies that all possible holonomy groups do occur; the trivial group, ${\mathbb{Z}}_2$ (5 families), ${\mathbb{Z}}_4$, ${\mathbb{Z}}_2{\times}{\mathbb{Z}}_2$ (5 families), and ${\mathbb{Z}}_4{\rtimes}{\mathbb{Z}}_2$ (2 families).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.640-643
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• 2001

Perdeuterated hexaflouroacetylacetonato-ytterbium [Yb(SOL-D)$_3$] complexes were synthesized by the keto-enol tautomerism reaction of Yb(SOL-H)$_3$in methanol-d$_4$in order to reduce the radiationless transition to the ligands. The luminescence properties of Yb(SOL-D)$_3$complex were measured in the following anhydrous deuterated organic solvents ; Methanol-d$_4$, THF-d$_{8}$, PO(O$CH_3$)$_3$and DMSO-d$_{6}$. The intensity, lifetime and quantum efficiency of the luminescence in DMSO-d$_{6}$ were superior to those in other deuterated solvents. It was suggested that the anhydrous DMSO-d$_{6}$ might be the most appropriate solvent for the liquid laser material of Yb(SOL-D)$_3$complex.complex.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.11
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• pp.511-516
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• 2002

$TiO_2-SnO_2$ thin films are fabricated using sol-gel method. In case the amount of water required hydrolysis smaller than that for stoichiometry, Ti sol forms clear sol which has normal chain structure. On the contrary, in case the amount of water required hydrolysis larger than that for stoichiometry, Ti sol forms suspended sol which has cluster structure. The thickness of thin films increase about $0.03{\sim}0.04{\mu}m$ every a dipping. The permittivity and dissipation factor of $TiO_2-SnO_2$ thin films decrease with increasing frequency. Thin films show semiconductive characteristics above $400^{\cric}C$.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.11a
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• pp.137-138
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• 2012

ZnO 박막을 Sol-gel용액을 이용한 스핀코팅 방법으로 석영기판 위에 성장하였고 Sol-gel 용액의 온도 변화에 따른 구조적, 광학적 특성을 분석하였다. ZnO 박막의 구조적, 광학적 특성을 조사하기 위해 field-emission scanning electron microscopy, X-ray diffraction (XRD), photoluminescence (PL), 그리고 ultraviolet-visible (UV) spectroscopy을 사용하였다. PL 분석에서 ZnO 박막은 orange 계열의 발광을 하였으며, PL spectra는 3.3 eV 부근의 near-band edge emission (NBE) 피크와 2.0 eV 부근의 deep-level emission (DLE) 피크로 이루어져있다. 모든 sol-gel 용액 온도에서, DLE 피크가 NBE 피크보다 더 우세하고 이 DLE 피크는 sol-gel 용액의 온도가 증가함에 따라 점점 증가하다가 감소하는 것을 알 수 있다. 이런 DLE 피크는 산소 공공, 아연 공공, 침입형 산소, 침입형 아연 등과 같은 결함에 의한 것이며, ZnO 박막은 sol-gel 용액의 온도에 따라 결함의 특성이 변화하였다.

• Journal of the Korean Ceramic Society
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• v.28 no.1
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• pp.60-66
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• 1991

The polymeric alumina sol was prepared by partial hydrolysis of aluminum sec-butoxide reacted with acetylacetone and its characteristics was investigated. The effects of alcohol solvent, acetylacetone, and acid concentration to the sol were investigated. FT-IR and Al27-MASNMR were used to study hydrolysis and polymerization reaction of aluminum complex. Synthesized sol showed the characteristics of polymeric alumina sol. To make a clear polymeric alumina sol, the optimum contents of acetylacetone, H2O and alcohol solvent were 0.4-0.6 mole, 0.25-1.25 mole, 3-5 mole per one mole alkoxide respectively. As a result of the Al27-MASNMR analysis, it was noted that hexa-penta-coordinated Al were main structure.

• Bulletin of the Korean Space Science Society
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• 2006.04a
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• pp.47-47
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• 2006

• Bulletin of the Korean Mathematical Society
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• v.57 no.4
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• pp.909-919
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• 2020

The 4-dimensional solvable Lie group Sol₀⁴ does not admit a lattice. The purpose of this paper is two-fold. We study poly-crystallographic groups of Sol₀⁴, and then we study Nielsen fixed point theory on the spaces modeled on Sol₀⁴.

• Journal of the Korean Ceramic Society
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• v.28 no.2
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• pp.153-159
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• 1991

Polymeric alumina sol and polymeric silica sol were synthesized from aluminum sec-butoxide and tetraethyl orthosilicate, respectively as starting materials. A clear mullite sol was obtained by mixing these sols. When the mullite sol had a proper viscosity which was dependent on drying time, the fibers were fabricated by spinning. The optimum viscosity for fabrication of mullite fibers was 103-104 cps, and the fibers with various sizeswere made using the sols. The mullite was a major phase of the calcined fibers and the diameters of the fibers were about 50$\mu\textrm{m}$.