• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1077-1079
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• 2000

In this paper. the design procedure of the inverter output filter is described. The transfer function of the filter output voltage to the load current is described with the capacitor value and the system time constant including the controller. This means that the relation between the filter capacitor value and the system time constant is given as the closed form. By using the above closed form. the capacitor value can be calculated with the system time constant which can be implemented practically not using the try and error method. And as the effect of the load current to the voltage distortion can be calculated from the closed form, it can be verified how much the voltage distortion is effected when the nonlinear load is connected.

• 센서학회지
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• 제23권2호
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• pp.114-121
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• 2014

We report a polysilicon active area membrane field effect transistor (PSAFET) pressure sensor for low stress deflection of membrane. The PSAFET was produced in conventional FET semiconductor fabrication and backside wet etching. The PSAFET located at the front side measured pressure change using 300 nm thin-nitride membrane when a membrane was slightly strained by the small deflection of membrane shape from backside with any physical force. The PSAFET showed high sensitivity around threshold voltage, because threshold voltage variation was composed of fractional function form in sensitivity equation of current variation. When gate voltage was biased close to threshold voltage, a fractional function form had infinite value at $V_{tn}$, which increased the current variation of sensitivity. Threshold voltage effect was dominant right after the PSAFET was turned on. Narrow transistor channel established by small current flow was choked because electron could barely cross drain-source electrodes. When gate voltage was far from threshold voltage, threshold voltage effect converged to zero in fractional form of threshold voltage variations and drain current change was mostly determined by mobility changes. As the PSAFET fabrication was compatible with a polysilicon FET in CMOS fabrication, it could be adapted in low pressure sensor and bio molecular sensor.

• 대한전자공학회논문지SD
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• 제44권7호통권361호
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• pp.16-23
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• 2007

본 논문에서는 완전 공핍된 SOI형 대칭 이중게이트 MOSFET의 문턱 전압에 대한 간단한 해석적 모델을 제시하고자 실리콘 몸체 내의 전위 분포를 근사적으로 채널에 수직한 방향의 좌표에 대해 4차 다항식으로 가정하였다. 이로써 2차원 포아송 방정식을 풀어 표면 전위의 표현식을 도출하고, 이 결과로부터 드레인 전압 변화에 의한 문턱 전압의 roll-off를 비교적 정확하게 기술할 수 있는 문턱 전압의 표현식을 closed-form의 간단한 표현식으로 도출하였다. 도출된 표현식으로 모의 실험을 수행한 결과 $0.01\;[{\mu}m]$의 실리콘 채널 길이 범위까지 채널 길이에 지수적으로 감소하는 것을 보이는 비교적 정확한 결과를 얻을 수 있음을 확인하였다.

• 한국전자통신학회논문지
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• 제8권9호
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• pp.1307-1312
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• 2013

본 논문에서는 알칼리성 또는 산성을 띠는 특정 용액 내에서 전기분해 원리를 이용하여 금속 표면을 산화시켜 절연피막을 형성하는 장치를 개발한다. 기존에는 주로 양극에만 펄스 형태로 전압을 인가하는 단극성(unipolar) 방식이지만 본 논문에서는 H-브리지를 이용하여 양극에 양(+)전압과 음(-)전압을 번갈아 가면서 전압을 공급하는 양극성(bipolar) 장치를 제작하였으며, 금속 시편의 특성에 맞는 다양한 전기적인 조건을 가지고 산화피막을 형성할 수 있는 장치를 개발하였다. 공급전류 가변은 PWM 변조를 이용하였으며, (+)와 (-)의 극성변화는 H-브리지를 이용하여 양극성 펄스전압을 공급할 수 있도록 하였다. 그 결과로써 단극성보다 균일한 기공을 갖는 피막이 형성되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.33-35
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• 2004

The secondary voltage control is the method the pilot bus controls the voltage of the voltage control area sufficiently uncoupled form its neighbours within a area to k slightly influenced by the actions carried out in the other areas. This paper presents the comparison of three methods which determines the voltage control area for the secondary voltage control in power system. Additionally, this paper selects the fitted thing of three methods determining the voltage control area, VSSA, and using it applies the procedure determining the voltage control area to KEPCO system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.904-906
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• 1998

PD pulses have about one nanosecond rise time in the $SF_6$ gas insulation. These pulses propagate in the apparatus to PD sensors in the form of the voltage oscillation, high frequency current and the electromagnetic radiation. In this paper, we investigated the characteristics of two types of PD sensors, by putting high frequency signals in the form of sine waves and pulse into the test apparatus in air. Also, we measured PD quantity from the needle electrode and the sensitivity of the sensors. We found that PD of 70pC could be detected with this method and the study in $SF_6$ gas should be carried out for application to $SF_6$ GIS.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.748-751
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• 2000

in this paper the design procedure of three phase voltage source inverter output filter is described. The 'd' axis transfer function of the filter output voltage to the load current is described with the capacitor value and the system time constant including the controller. This means that the relation between the filter capacitor value and the system time constant is given as the closed form. By using the above closed form the capacitor value can be calculated with the system time constant is given as the closed,. form the capacitor value can be calculated with the system time constant which can be implemented practically not using the try and error method. And as the effect of the load is connected.

• 한국정밀공학회지
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• 제13권1호
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• pp.22-28
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• 1996

From the experimental study of Wire-Cut Electric Discharge Machining of STD-11 alloy steel and P-20 tungsten carbide, the characteristics such as hand drum form and discharge gap have been observed and evaluated for various conditions. Hand drum form can be improved when gap have been observed and evaluated for various conditions. Hand drum form can be improved when gap voltage and spark cycle become smaller, thickness become thinner, wire tension become larger and the no of cutting increases. When 60mm thickness tungsten carbide is cut in normal condition, hand drum form becomes larger due to the low conductivity machining allowance become slightly larger when peak discharge current and gap voltage become larger, or wire tension becomes smaller. Under the same condition, machining allowance of tungsten carbide is larger than alloyed steel by 1/100mm.

• 전기학회논문지P
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• 제56권2호
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• pp.83-89
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• 2007

The LC filter design procedure of the inverter output filter is described. The transfer function of the filter output voltage to the load current is described with the capacitor value and the system time constant considering the system controller. By using the closed form of the relation between the filter capacitor value and the system time constant, the capacitor value can be calculated with the given system time constant and vice versa. It is more practical for the implementation of power and control circuit of inverter. And as the effect of the load current to the voltage distortion can be calculated from the closed form, it is possible to analyze the system how much the voltage waveform is distorted in case of the nonlinear load. All the proposed design procedure is verified with the simulation and experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 전문대학교육위원
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• pp.206-211
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• 2005

The LC filter design procedure of the inverter output filter is described. The transfer function of the filter output voltage to the load current is described with the capacitor value and the system time constant considering the system controller. By using the closed form of the relation between the filter capacitor value and the system time constant, the capacitor value can be calculated with the given system time constant and vice versa. It is more practical for the implementation of power and control circuit of inverter. And as the effect of the load current to the voltage distortion can be calculated from the closed form, it is possible to analyze the system how much the voltage waveform is distorted in case of the nonlinear load. All the proposed design procedure is verified with the simulation and experimental results.