• Journal of Information Display
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• 제8권3호
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• pp.17-21
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• 2007

We introduce a new electrode structure for the patterned vertical alignment (PVA) mode, which has a lower color-shift at large viewing angle than the one-domain VA mode. By manipulating the period of electrode structure, we can make more multi-domains and use the existing fabrication processes without having to use additional materials.

• Elastomers and Composites
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• 제29권3호
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• pp.226-233
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• 1994

The properties of the mixed prepolymer-urethane in the range of 10-40 phr were observed. LBR and LCR have same functional group but different in structure of molecular. The viscosity of mixture depending on content of rubber, adhesive strength, thermal property and compatibility with a diluted solvent are as follows: 1. The viscosity of the mixture was influenced by solubility of the diluent for urethane resin and liquid rubber. 2. Adhesive strength showed the highest value at 30phr rubber, decreased gradually at above 30phr rubber. And LBR revealed better physical property than that of LCR. 3. The most effective factors affecting adhesive strength are molecular structure of rubber, the type of solvent, and volatility. 4. Urethane resin containing LBR showed better compatibility for solvent and faster drying velocity. 5. LBR showed more favorable compatibility and dispersion state than those of LCR by analyzing the results of SEM.

• 대한화학회지
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• 제11권3호
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• pp.105-110
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• 1967

액체구조의 천이상태이론을 아산화질소($N_2O$)와 사산화질소($N_2O_4$)에 적용하여 이 액체들의 상태합을 유도하였다. 이상태합들을 써서 각 액체의 몰부피, 증기압, 증발엔트로피, 임계점에서의 성질 등, 여러가지 열역학적양들을 계산한 결과 모두 실험치와 좋은 일치를 얻었다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.1137-1141
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• 2004

In this paper, we have improved a novel ECB mode using bend structure with high tilt angle in the unique condition by Hot plate equipment. The new control of tilt angle for nematic liquid crystal (NLC) with negative and positive dielectric anisotropy on the rubbed homeotropic polyimide (PI) using baking method by Hot plate equipment was investigated. LC tilt angle decreased with increasing baking temperature and time. We suggest that the development of the novel ECB cell using control of tilt angle on the homeotropic surface is a promising technique for the achievement of fast response time and high contrast ratio.

• 한국염색가공학회지
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• 제2권4호
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• pp.237-244
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• 1990

Syntheses and liquid-Crystallinites of thermotropic copoly (ester amide)s were investigated. The three components melt polycondensation of 4,4'-dicarboxy-$\alpha$, $\omega$-diphenoxyalkane as an A component, 4-4'diacetoxybiphenyl as a B, and p-N-acetoxy-aminobenzoic acid as a C gave the thrmotropic copoly(ester amide)s containing a flexible splacer in the polymer backbone. Diacetylated hydroquinone, methyl hydroquinone, chlorohydroquinone, and phenyl hydroquinone were used as anther B components. A polymer(6BPAB) having 10 mol% of C component and hexamethylene space. showed a typical nematic texture between $245^{\circ}C(T_m)\; and\; more\; than\; 360^{\circ]C(T_i)$. The melting points of the members of this series of polymers increased with decreasing methylene spacer. The polymer structure and mesomorphic nature were examined by solid and solution ^{13}C-NMR4 spectroscopy, cross polarizing microscopy with a hot stage, and X-ray diffactometry.

• 한국인쇄학회지
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• 제13권1호
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• pp.1-12
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• 1995

Polymeric mesogens having a regularly alternating rigid-flexible repeating structure in the main-chain polymer exhibit distinct even-odd oscillation in their thermodynamic quantities with respect to the number of methylene units in the spacer. The even-odd oscillation depends on the number of methylene groups in the spacer the entropy change at the NI(nematic-isotropic) phase transition becomes less distinct when the linking group is replaced by the carbonate. In our previous work, we have suggested that the characteristics arise from the geometrical arrangement of the linkage. In this work, we have prepared a series of carbonate-type monomer and dimer liquid crystals. The thermodynamic behaviors at the NI phase transition have been compared with those previous reported for the ether- or ester-type liquid crystals. For the dimer series, the orientational order parameter of the mesogenic core was determined by using H-NMR technique. The origin of the difference observed among linking groups was found to the geometrical characteristics of chemical structure.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.33-35
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• 2012

This study has been mainly motivated to numerically model the supercritical mixing and combustion processes encountered in the liquid propellant rocket engines. In the present approach, turbulence is represented by the extended k-e model. To account for the real fluid effects, the propellant mixture properties are calculated by using generalized cubic equation of state. In order to realistically represent the turbulence-chemistry interaction in the turbulent nonpremixed flames, the flamelet approach based on the real fluid flamelet library has been adopted. Based on numerical results, the detailed discussions are made for the effects of swirl number on flame structure of supercritical kerosene/LOx double swirl coaxial injector.

• 한국재료학회지
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• 제13권5호
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• pp.285-291
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• 2003

The nanosized silver and gold particles are prepared by ERC method in which metal vapors with high temperature is rapidly quenched by coolants such as liquid nitrogen or liquid argon. In order to monitor the crystal structural changes on the internal and the surface of the nanosized noble metal particles, lattice parameter, internal strain and Debye-Waller factor are investigated, and the calculation of X-ray diffraction scattering intensity is performed. The lattice parameters of silver and gold particles agree with those of bulk materials, and crystal internal strain of the metal particles is not changed by rapid cooling. The Debye-Waller factor of gold particles is increased with decreasing particle size because of the surface softening phenomenon of nanosized particles, but the crystal structural change on the surface of the particles is not detected from the comparison the calculated X-ray diffraction profile with the experimental profile on gold particles with the particle size of 4 nm.

• Journal of Information Display
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• 제9권2호
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• pp.22-27
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• 2008

We propose an optical configuration of a vertical alignment (VA) liquid crystal (LC) cell to eliminate the light leakage in the diagonal direction. VA LC cell has an excellent contrast ratio in the normal direction due to the no phase-retardation. However, change of the phase-retardation occurs in all directions, which causes the light leakage and deteriorates the characteristics of the dark state. We designed the LC cell structure composed of multiple combinations with two A-plates and two C-plates in order to achieve wide viewing property on the Poincare sphere. From calculations, we show that the proposed structure can improve the viewing angle characteristics by compensating for the light leakage in all directions.

• 한국세라믹학회지
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• 제44권8호
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• pp.412-418
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• 2007

The atomic scale details of the melting of solid argon were monitored with the aid of molecular dynamics simulations. The potential energy distribution is substantially disturbed by an increase in the interatomic distance and the random of set distance from the lattice points, with increasing temperature. The potential energy barriers between the lattice points decrease in magnitude with the temperature. Eventually, at the melting point, these barriers can be overcome by atoms that are excited with the entropy gain acquired when the atoms obtain rotational freedom in their atomic motion, and the rotational freedom leads to the collapse of the crystal structure. Furthermore, it was found that the surface of crystals plays an important role in the melting process: the surface eliminates the barrier for the nucleation of the liquid phase and facilitates the melting process. Moreover, the atomic structure of the surface varies with increasing temperature, first via surface roughening and then, before the bulk melts, via surface melting.