• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.198-201
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• 2004

We have developed a multi-domain vertically aligned liquid crystal display (MVA-LCD) that produces natural gray-scale images even at high viewing angles. We divided each pixel into two areas and set different threshold voltages for each sub-area. A transparent electrode in a sub-area is not connected directly to the source electrodes but via the capacitance of the SiN layer. In particular, light-orange skin color appears very natural, even at a high inclination angle. The contrast ratio is over 500 in the normal direction and over 10 from any viewing angle.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권5호
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• pp.203-210
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• 2003

This paper describes high voltage and high energy density capacitor developed for pulsed power applications. The rated voltage of the developed capacitor is DC 22 [kV], the capacitance is 206 [$\mu$F] and the energy density is about 0.7 [kJ/kg]. Polypropylene film and kraft paper were used as the dielectrics. The ratio of the thickness of each dielectric material which consists of the composite dielectric structure, stacking factor and the termination method were determined by the charging and discharging tests on model capacitors. In terms of energy density, the developed capacitor has higher energy density compared with the products of foreign leading companies. In addition, it has been proved that the life expectancy can be more over 2000 shots through the charging and discharging test. The voltage reversal factor was 20%. This capacitor can be used as numerous discharge applications such as military, medical, industrial fields.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권3호
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• pp.104-109
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• 1999

In order to design and predict the performance of the harmonic side drive motor, it is necessary to analyze the torque generated by the structure. In this paper, an analytical model is proposed for design. Conformal mapping is used to model the capacitance and torque of the motor as a function of the rotor angular position with two-dimensional approximation. Then the result of conformal mapping analysis is verified with F.E.M result.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.434-436
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• 1996

This paper investigates the optimal design of an electronic ballast of half bridge inverter type in consideration of the variation of ambient temperatures for a 15[W] triple-type compact fluorescent lamp. The performances of electronic ballasts under different values or the capacitance ratio in the resonant tank circuit are compared with each other in the practical temperature range between 15[$^{\circ}C$] and 35[$^{\circ}C$] to determine its optimum value. As a result, the optimum value is found to be such that $C_1/C_2=10$ at which value starting of the lamp is most stable and light output reaches its maximum value with lowest variation.

• Journal of Mechanical Science and Technology
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• 제17권11호
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• pp.1650-1658
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• 2003

This paper deals with a novel shunt circuit, which is capable of suppressing multimode vibration amplitudes by using a pair of piezoceramic patches. In order to describe the characteristic behaviors of a piezoelectric damper connected with a series and a parallel resistor-negative capacitor branch circuit, the stiffness ratio and loss factor with respect to the non-dimensional frequency are considered. The mechanism of the shunt damper is also described by considering a shunt voltage constrained by shunt impedance. To obtain a guideline model of the piezo/beam system with a negative capacitive shunting, the governing equations of motion are derived through the Hamilton's principle and a piezo sensor equation as well as a shunt-damping matrix is developed. The theoretical analysis shows that the piezo/beam system combined with a series and a parallel resistor-negative capacitor branch circuit developed in this study can significantly reduce the multiple-mode vibration amplitudes over the whole structural frequency range.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.569-572
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• 2009

In this study, HFC ORCs (Organic Rankine Cycles) are investigated for a low-temperature geothermal power generation by a simulation method. A steady-state simulation model is developed to analyze and optimize cycle's performance. The model contains a turbine, a pump, an expansion valve and heat exchangers. The turbine and pump are modelled by an isentropic efficiency. Simulations were carried out for the given heat source and sink inlet temperatures, and given flow rate that is based on the typical power plant thermal-capacitance-rate ratio. 3 HFC fluids are considered as a candidate for a working fluid of low-temperature ORCs. In this study, all optimized HFC ORCs are shown to yield almost the same performance in terms of power for a low-temperature heat source of about $100^{\circ}C$.

• 한국진공학회지
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• 제4권S1호
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• pp.145-150
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• 1995

PZT thin films were fabricated on Pt/Ti/SiO2/Si substrates at $500^{\circ}C$ by ECR-PECVD for the application to the charge storage capacitor of ULSI DRAMs. Perovskite single phase PZT films were obtained by controling the film compositional ratio Pb/(Zr+Ti) close to 1. The anion concentrations in the PZT films were successfully controlled by adjusting the flow rates of each MO sources. Capacitance of a typical 94 nm thick PZT film prepared at $500^{\circ}C$ in this work was about 5.3 uF/$\textrm{cm}^2$, which corresponds to the equivalent SiO2 thickness of 0.65nm.

• 한국진공학회지
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• 제5권3호
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• pp.223-228
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• 1996

$SiO_2$ insulator layers on InSb have been prepared by remote PECVD system a low temperature below $200^{\circ}C$. The effects of deposition pressure, temperature, and gas flow ratio on the physical and electrical characteristics of the $SiO_2$ were studied. The InSb MIS device using $SiO_2$ was fabricated and measured its current-voltage and capacitance-voltage characteritance-voltage charateristics at 77K. The films evaluated Auger electron spectroscopy showed that composition atoms were distributed uniformaly throughout the oxide film and the outdiffusion of substrate atoms into the oxide were few. The leakage current density of the MIS device was about 6.26nA/$\textrm{cm}^2$ at 0.75MV/cm , and the breakdown voltage was about 1MV/cm. The interface-stage density at mid-bandgap extracted from 1MHz C-V measurement was $54\times 10^{11}\textrm{cm}^2-2V^{-1}$.

• 한국전기전자재료학회논문지
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• 제14권10호
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• pp.802-807
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• 2001

The (S $r_{0.85}$C $a_{0.15}$)Ti $O_{3}$(SCT) thin films are deposited on Pt-coated electrode (Pt/TiN/ $SiO_2$/Si) using RF sputtering method. The composition of SCT thin films deposited on Si substrate at woom temperature is close to stoichiometry(1.102 in A/B ratio). The maximum dielectric constant of SCT thin films is obtained by annealing at 600[$^{\circ}C$]. The capacitance characteristics had a stable value within $\pm$4[%]. The drastic decrease of dielectric constant and increase of dielectric loss in SCT thin films is observed above 200[kHz]. SCT thin films used in this study show the phenomena of dielectric relaxation with the increase of frequencey.cey.

• 한국자기학회지
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• 제1권1호
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• pp.30-36
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• 1991

전기용량법에 의한 자기이방성 측정장치를 설계 제작하였다. 균이자기장 속에서 원판 또는 구형의 시료가 자기이방성에 의해 받는 토오크를 평행판 축전기의 미소용량 변화로 변환하여, 그것을 변압기 부리지 로 검출하였다. 3% Si-Fe 단결정의(100)면에 대한 입방 이방성 $K_{1}$은 $3.3{\times}10^{4}\;J/m^{3}$가 얻어졌으며, 교정에는 Ni선의 형상이방성을 이용하였다. 기타 수종의 시료에 대한 결과도 기존치와 좋은 일치를 보였다.