• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 춘계학술대회 논문집
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• pp.35-38
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• 1995

Indium Tin Oxide(ITO) thin film is transparent to visible ray and conductive in electricity. It is seen that the samples made by the sputtering process have high transmission rate to visible ray and high adhesion , but the planar type magnetron sputtering process with is very well known in industrial region have a defect of partial erosion on the surface of target and a high loss of target and also since the substrate is positioned in plasma, the damage on thin film surface is caused by the reaction with plasma. In cylindrical magnetron sputtering system. it is known that the loss of target is little , the damage of thin film is very little and the adhesion of thin film with substrate is strong. In this study, we have made ITO thin film in the cylindrical DC magnetron system with the variable of substrate temperature , magnetic field, vacuum condution and the applied voltage. The general temperature for formation on ITO is asked at 350 $^{\circ}C$~400$^{\circ}C$ but we have made ITO is low temperature(80-150$^{\circ}C$) By studing electrical and optical properties of ITO thin fims made by varing several condition, we have searched the optimal condition for formation in the best ITO in low temperature.

• 한국안전학회지
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• 제21권4호
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• pp.25-32
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• 2006

LonWorks over IP(LonWorks-IP) virtual device network(VDN) is an integrated form of LonWorks device network and IP data network. In especially real-time distributed servo applications on the factory floor, timely response is essential for predictive and preventive maintenance. The time delay in servo control on LonWorks-IP based VDN has highly stochastic nature. LonWorks-IP based VDN induced transmission delay deteriorates the performance and stability of the real-time distributed control system and can't give an effective preventive and predictive maintenance. In order to guarantee the stability and performance of the system, and give an effective preventive and predictive maintenance, LonWorks-IP based VDN induced time-varying uncertain time delay needs to be predicted and compensated. In this paper new Pill control scheme based on Smith predictor, disturbance observer and band pass filter is proposed and tested through computer simulation about position control of DC servo motor. It is shown that how can the proposed control scheme be designed to minimize the effects of uncertain varying time delay and model uncertainties. The validity of the proposed control scheme is compared and demonstrated with the comparison of internal model controllers(IMC) based on Smith predictor with and without disturbance observer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1369-1372
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• 1999

We investigated the current limiting characteristics of resistive and inductive SFCLs with 100${\Omega}$ of Quench impedance for a double line-to-ground fault, in the 154 kV transmission system. The fault simulation at the phase angles $0^{\circ}$, $45^{\circ}$, and $90^{\circ}$ showed that the resistive SFCL limited the fault current less than 17 kA without any DC component after one half cycle from the instant of the fault. On the other hand, the inductive SFCL suppressed the current below 12 kA, but with 3$\sim$5 kA of DC component which decreased to zero in 6 cycles. We concluded that the inductive SFCL had higher performance in current limiting but the resistive SFCL was better from the view point of DC components.

• 전자공학회논문지D
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• 제36D권6호
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• pp.87-96
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• 1999

협대역 마이크로파 아날로그 광전송을 위한, 이중 변조구조를 이용한 새로운 전광 전계흡수 광변조기의 선형화 방법이 제안되었으며, 이론적으로 고찰되었다. 주-변조기와 소자 길이, 흡수층의 밴드갭 파장 그리고 DC 바이어스 전압을 달리하는 부-변조기의 주-변조기와의 이중 변조구조를 적용하여, 주-변조기의 3차 비선형 왜곡 성분인 CTB(composite triple beat distortion)를 최소화하는 동작점이 작은 바이어스전압으로 이동함과 더불어 ~30dB의 CYB의 억제효과를 얻을 수 있었다. CTB의 억제에 따라 협대역 채널 대역에서의 ~20dB 동작영역의 향상을 이룰 수 있었다.

• 한국전자파학회논문지
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• 제29권4호
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• pp.285-289
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• 2018

본 논문에서는 지능적인 원거리 무선전력전송의 방식으로 시간 역전(time reversal) 기반 전파 집속 방법을 제시하였다. 시간 역전 기반의 무선전력전송은 복잡한 전파환경에서도 기기의 위치에 상관없이 전파를 선택적으로 집속하여 높은 peak 전력을 전달할 수 있다. 현실과 가까운 전파환경 시뮬레이션을 통하여 시간 역전 기반의 시 공간 전파 집속 현상을 검증하였고, 집속된 RF를 정류하여 전달된 DC 전압을 확인하였다. 또한 일반적인 협대역 신호(CW) 대비 시간 역전 신호의 peak 향상률과 정류 전력비를 확인한 결과, 최대 12 dB 향상된 peak 전력이 전송되었으며, 따라서 보다 높은 효율로 전력전송이 이루어짐을 확인하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.327-327
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• 2013

본 연구에서는 $SiO_2$ Target과 $In_2O_3$ Target으로 co-sputtering방법을 이용해 증착한 Si-doped $In_2O_3$ (ISO) 박막의 Si 도핑 농도에 따른 전기적, 광학적, 구조적 특성에 대해 연구하였고, 이를 유기태양 전지(OPVs) 에 적용함으로써 그 가능성을 타진하였다. $In_2O_3$ target의 DC power를 100 W로 고정시킨 채 $SiO_2$ target의 RF power 크기를 20~60 W 변화시키면서 상온에서 실험을 진행한 결과 최적 조건은 박막의 두께가 200 nm일 때 Working pressure는 3 mTorr이고, RF power는 50 W이었다. 이 조건으로 제작된 ISO 박막은 550 nm에서 81.51%의 광투과율과 51.91 Ohm/sq.의 비교적 낮은 면저항이 나타남을 Hall measurement 및 UV/Vis spectroscopy 분석을 통해 알 수 있었다. 또한 X-ray diffraction 분석법과 Transmission Electron Microscope 분석법을 통해 $SiO_2$ 도핑 power가 50 W 이상으로 증가할 경우 ISO 박막의 결정성이 감소하여 완벽한 비정질상의 ISO 투명박막이 형성됨을 확인할 수 있었다. 비정질 특성을 갖는 ISO 투명 전극을 이용하여 유기 박막형 태양전지를 제작한 결과 Voc (0.576 V), Jsc (7.671 mA/$cm^2$), FF (62.96%), PCE (2.78%)의 특성을 나타냄으로서 co-sputtering 공정을 통해 최적화된 ISO 박막을 유기 박막형 태양전지에 적용함으로써 광전소자로의 적용 가능성을 확인할 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.500-501
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• 2005

Aluminum doped zinc oxide films (ZnO:Al) were deposited on glass substrate by DC magnetron sputtering from a ZnO target mixed with 2 wt% $Al_2O_3$. The effects of substrate bias on the electrical properties and film structure were studied. Films deposited with positive bias have been annealed at $600^{\circ}C$ using rapid thermal anneal (RTA) process. The effects of RTA on the evolution of film microstructure are to be also studied using X-ray diffraction, transmission electron microscopy, and atomic force microscopy. Positive bias sputtering may induce lattice defects caused by electron bombardments during deposition. The as-deposited film microstructure evolves from the film with high defect density to more stable film condition. The electrical properties of the films after RTA process were also studied and the results were correlated with the evolution of film microstructures.

• 대한전기학회논문지
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• 제41권9호
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• pp.973-983
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• 1992

A very fast algorithm, using fast Haar transformation with half a cycle dc-offset free data, to extract the power frequency components and to detect faults in power systems is proposed. For the speed-up, two important techniques are used. First, according to the symmetric characteristics of sine and cosine functions, fundamental frequency components are calculated with only half a cycle sample data. For using these characteristics, post-fault de-offset components must be removed beforehand. Therefore, secondly, a newly designed digital filter is used to remove exponentially decaying dc-offset from the post-fault signal. In accordance with series simulations, transmission line faults can be detected in around half a cycle after faults.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.161-165
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• 2003

In this paper, A new controller for power factor and harmonics compensation of a single-phase PWM converter is described. The proposed controller requires only the dc voltage sensor and the at current sensor to compensate the power factor and harmonics. Detail simulation model with EMTBC (Electro-Magnetic Transient program for DC transmission) including power circuit and controller was developed to verify the operation of proposed controller. The application feasibility of the proposed controller was verified through experimental works with a prototype. The proposed controller has a simple structure in the point of hardware implementation, and shows excellent performance in normal operation as well as in sudden load change.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권10호
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• pp.618-624
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• 2004

In this paper, a new controller for a single-phase PWM converter is described, which requires only two input parameters, the dc voltage and the ac current. Detail simulation model with EMTDC(Electro-Magnetic Transient program for DC transmission) including power circuit and controller was developed to verify the operation of proposed controller. The application feasibility of the proposed controller was verified through experimental works with a prototype. The proposed controller has a simple structure in the point of hardware implementation, and shows excellent performance in normal operation as well as in sudden load change.