• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.48-50
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• 2001

This paper presents the switching angle and the 1/2-phase hybrid exciting method to minimize torque ripple in the 6/4 Switched Reluctance Motor (SRM). The inductance in SRM is dependent on rotor position and current. Therefore, the inductance profile is expressed as an approximate function based on FEM data. And then, the dynamic characteristics are simulated by Matlab simulink using the derived inductance function. The torque ripple resulting from single phase exciting and 1/2-phase hybrid exciting is compared.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.634-643
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• 2011

The neutral section was installed in order to prevent conflict with different phase angle source in electric railway catenary system. The speed of electric train reduced due to coasting operation by notch off when it passed the neutral section. And, the catenary wire was damaged and the accident might be happened because of the arc generation when the electric train passed the neutral section with notch off condition. The inrush current of main transformer installed tiling train is analyzed during the operation of MCB(main circuit break) passing through the neutral section. The instantaneous waveform of load current were analyzed in case of powering and regenerative braking. Inrush current waveform with run of AC railway train showed that inrush current waveform and harmonics, the inrush current generated from main transformer in train has bad effects on power quality problem. In order to reduce these inrush currents, the MCB is connected when the phase angle of voltage is 90 degree. This paper is to measure inrush current and harmonics in main transformer of high speed train in neutral section of electric railway. This measurement report is used to control minimum inrush current in algorithm and power phase angle.

• 한국정밀공학회지
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• 제30권12호
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• pp.1335-1340
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• 2013

Herein the water film was introduced to the hydrophilic area on the line patterned surface to solve the contradiction caused by surface roughness (high different wettability has advantage to control the droplet but high roughness for that high wettability difference causes obstruction of droplet moving). Thus the droplet on the water film could not be hindered to line direction but restricted to orthogonal direction, effectively. In addition, droplet behaviors according to droplet volume and line thickness were studied. Droplet fell off the line with narrowing the interface between the droplet and the water film on the line. When the droplet fell off the line, the plate angle was designated as a critical plate angle and it used as an indicator of surface capability to control the droplet. As a result critical plate angle increases as droplet volume decreases and line thickness increases.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권11호
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• pp.575-582
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• 2001

This paper presents a calculating method of switching angle for adaptive switched reluctance motor (SRM) drive of a drill. The operation of the SRM is completely characterized by the flux linked by one phase winding which depends only on the current in that same phase winding and the rotor position. An efficiently adaptive SRM drive is possible on appropriately scheduling the commutation angles with accurate rotor position, supplied current value and speed information. An adaptive SRM drive with reduction torque ripple should be controlled by an optimized phase current control along with rotor position. Therefore, we are suggested a computing method of switching turn-on and off angles for adaptationally SRM operation with varied rotor speed and load. To probe the computing method, we have some simulation and experiment, it is shown a good result that can be computing the optimized switching angles for an electric drill motor.

• 한국통신학회논문지
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• 제28권10C호
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• pp.949-957
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• 2003

본 논문은 이동통신 환경하에서 각도퍼짐(Angle Spread)이 증가하여도 우수한 성능을 유지하는 그래디언트 온-오프 빔형성 알고리즘을 제안한다. 제안된 방법은 수신 벡터신호의 자기상관행렬의 최대 고유치에 대응하는 고유벡터를 이용하되 상대적으로 큰 고유치에 대응하는 2개 고유벡터를 이용하여 다이버시티 이득을 얻음으로써 하나의 고유벡터 하나만 이용하는 방법[1]보다 우수한 성능을 나타난다. 본 제안된 방법을 IS-2000 1X신호환경에서 모의실험 결과 각도퍼짐이 증가하여도 기존의 하나의 고유벡터 하나를 사용하는 알고리즘보다 성능이 우수함을 확인 하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제26권1호
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• pp.10-13
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• 2024

We performed angle-resolved Raman spectroscopy experiments on lead-doped and undoped Bi₂Sr₂CaCu₂O_8+δ(Bi2212) samples using a 660 nm laser and analyzed the Raman tensor of the phonon modes. The phonon mode was clearly observed at the 60, 103, and 630 cm^-1 Raman shifts. The 60, 630 cm^-1 peaks were only clearly observed when the incident and scattered light polarizations were configured to be parallel. The polarization angle dependence of the amplitude of the 60, 630 cm^-1 peak on the parallel configuration shows a twofold symmetry; therefore, both peaks originate from Ag phonons and the crystal structure of Bi2212 should be considered orthorhombic. On the other hand, the 103 cm^-1 peak is clearly observed in both parallel and perpendicular configurations. Remarkably, the off-diagonal component of the Raman tensor of the 103 cm^-1 peak showed an anti-symmetry that could not be realized within the known crystal structure of Bi2212. The implications of our findings are discussed.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.459-462
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• 2002

We report viewing angle characteristics of the Ultra-FFS TFT-LCD. The FFS mode is known to exhibit both a wide viewing angle and high transmittance, owing to the approximated in-plane rotation of the LC director. Nevertheless, in the bright state, the device shows bluish and yellowish color parallel and perpendicular to the LC director at off-normal directions since the LC director rotates onl.v in one direction, and in addition, the grey scale inversion exists in large oblique viewing angle. However, the Ultra-FFS shows no grey scale inversion and no color shift in wide viewing angle range.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.231-234
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• 2001

The torque of SRM depends on phase current and the derivative of inductance. But the inductance of SRM is nonlinearly changed according to rotor position angle and phase current because of saturation in magnetic circuit. Therefore this has a concern in torque ripple and speed variation, and it is difficult to control the desired torque The torque of SRM depends on phase current and the derivative of inductance. But the inductance of SRM is nonlinearly changed according to rotor position angle and phase current because of saturation in magnetic circuit, and it is difficult to control the desired torque. This paper proposes an optimization control scheme by adjusting both the turn-on and turn-off angle according to high efficiency points which are simulated by GA-Neural Network, which is used to simulate the reasonable switching angle which is nonlinearly varied with rotor speed and load.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.74.2-74
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• 2002

$\textbullet$ Roll Control $\textbullet$ Switched Reluctance Motor $\textbullet$ Field Programmable Gate Array $\textbullet$ Single Pulse Mode Current Control $\textbullet$ OR/Off Angle Control

• 한국광학회지
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• 제30권1호
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• pp.8-14
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• 2019

본 논문에서는 추가적인 광학부품 및 조립공정 없이 차량용 헤드램프의 cut-off line에서 발생하는 색수차를 보정하는 방법과 이를 평가하는 방법을 제안한다. 기하학적인 방법으로 색수차를 보정하기 위해 비구면 프로젝션 렌즈의 볼록면에 tilt를 적용하여 파장별 최대 출사각도의 차이를 줄였으며, 색수차를 평가하기 위한 위치와 광도를 정하고 색 좌표를 통해 색수차 기준을 제시하였다. 이러한 기하학적인 방법을 이용하여 설계된 자동차용 헤드램프를 평가한 결과 cut-off line의 색수차가 상당히 감소되었음을 확인할 수 있었다.