• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2326-2328
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• 1999

Developments of effective and economic diagnostic apparatus for industrial plastic insulated high voltage power cables are in discontented condition still. Some report told that DC high voltage was damaged plastic insulation of a partially aged power cable to lead breakdown easily. But now, we have no alternative tools of DC diagnostic apparatus, and we try to reduce a possibility of hazard DC diagnosis. DC diagnostic apparatus still have many advantages to field cable engineer like low price, portability easy applications and sufficient data. Main hazard of DC diagnosis is excessive hight of applied voltage Recent developments for DC diagnosis use considerably low voltage. But new test methods need special measuring device and manipulator, like high input impedance voltmeter, low leakage current high voltage switches, etc. So that reason, new DC diagnostic devices are normally very expensive and have low efficiency, economically. We try to design a composite test device for 3$\sim$4 newly developed method, have economical benefit th industrial engineer.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 영호남 합동 학술대회 및 춘계학술대회 논문집 센서 박막 기술교육
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• pp.74-76
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• 2006

An external electrode fluorescent lamp (EEFL) has an advantage of a long lifetime in the ear1y stages of the study on plasma discharge, interest in the lamp continues. Researches on the operation of external electrode fluorescent lamps have focused mainly on its use of a type of high frequency (MHz). By performing high brightness using a square wave operation method with the low frequency below 100kHz, which is applied to a narrowed tube type lamp that has several mm of lamp diameter, EEFL presented the possibility of using it as a light source for back-lights. However, because EEFL generates plasma using wall charges, which considers the impedance characteristics of glass based on the structural principle in discharge, it can be significant1y affected by frequency. Thus, this study verified the change in the characteristics of electromagnetic fields according to the change in frequency through a Maxwell's electromagnetic field simulation and examined the relationship between the change in the EEFL frequency and brightness by measuring the optical characteristics. In addition, the characteristics of the transformation of energy orbits were verified by investigating the characteristics of the wavelength according to the change in frequency through the OES.

• Macromolecular Research
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• 제13권6호
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• pp.514-520
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• 2005

Composite membranes of Nafion and sulfonated poly(arylene ether sulfone) were prepared. Sulfonated poly(arylene ether sulfone)s with different degrees of sulfonation were blended with Nafion to reduce the methanol crossover. The morphology, proton conductivity and methanol permeability of the resulting composite membranes were investigated by SEM, EDAX, AC impedance spectroscopy and permeability measuring instrument. The cross­sections of the composite membranes showed a phase separated morphology. The morphology and phase separation mechanism could be controlled by varying the blend ratio and the degree of sulfonation of poly(arylene ether sulfone). These complex morphologies can be applied for reducing methanol crossover. The methanol permeability and proton conductivity of the composite membranes were lower than those of Nafion 117 membrane since the development of an ionic pathway in the blend membrane was more difficult than that in Nafion itself.

• Macromolecular Research
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• 제16권5호
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• pp.457-466
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• 2008

The relation between the phase separated morphologies and their transport properties in the polymer blend membrane for direct methanol fuel cell application was studied. In order to enhance the proton conductivity and reduce the methanol crossover, sulfonated poly(arylene ether sulfone) copolymer, with a sulfonation of 60 mol% (sPAES-60), was blended with nonsulfonated poly(ether sulfone) copolymer (RH-2000, Solvay). Various morphologies were obtained by varying the drying condition and the concentration of the casting solution (10, 15, 20 wt%). The transport properties of proton and methanol molecule through the polymer blend membranes were studied according to the absorbed water. AC impedance spectroscopy was used to measure the proton conductivity and a liquid permeability measuring instrument was designed to measure the methanol permeability. The state of water in the blend membranes was confirmed by differential scanning calorimetry and was used to correlate the morphology of the membrane with the membrane transport properties.

• 한국인터넷방송통신학회논문지
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• 제15권6호
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• pp.239-244
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• 2015

최근들어 임펄스 레이더에서 거리를 측정하기위한 센서로서 또는 비 압축 고속 영상데이터의 전송용으로 UWB 기술이 활발히 응용되고 있다. 그러나 UWB 기술은 대역이 옥타브 밴드로 매우 넓어서 시스템을 설계하기가 쉽지 않다. 특히 광대역 임피던스를 정합해야하는 안테나를 비롯한 RF분야에서 더욱 그렇다. 본 연구에서는 이러한 3~6GHz 옥타브 대역에서 사용할 수 있는 시뉴어스 안테나를 설계하고 제작하였다. 그리고 유전체 렌즈를 설계하여 부착하여 이득을 높이는 실험한 결과 3~6GHz 사용대역에서 6~10dBi의 높은 이득을 얻을 수 있었다. 제작된 유전체 부착 시뉴어스 안테나를 HD 비디오 데이터 전송에 사용하였다. 전송 결과 10mW의 무선전력으로 최대 전송 거리는 90m였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.475-476
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• 2007

Electroglottography (EGG) is a technique used to register laryngeal behavior indirectly by a measuring the change in electrical impedance across the throat during speaking. However, EGG waveform is affected by laryngeal muscles which fluctuate the vocal cords, and which result in baseline wander. It is required to reduce baseline wander in EGG waveform, because EGG waveform is used for input signal of nonlinear speech synthesizer in next chapter. In vocal cords, the abduction-adduction of glottis is mainly controlled by the posterior cricoarytenoid (abductor) and interarytenoid (adductor) muscles respectively. Empirical Mode Decomposition method was adopted in cancellation of EGG waveform baseline wandering, and showd better performance than that of high pass filter with 500 order.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.779-785
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• 2006

본 논문은 고속선에 사용 중인 UM71-C 궤도회로의 결함진단을 위한 내부 모델링 결과를 나타낸다. 실제, 고속선 운행선상의 샘플개소를 선정하여 환경에 따른 선로정수를 구하고 전송라인의 특성임피던스와 전파정수를 반영시켜 단락전류에 대한 시뮬레이션을 수행하였으며, 임의의 지점에 결함을 발생시켜 측정한 결과와 시뮬레이션 수행한 결과를 비교하였다. 이러한 모델링 작업은 궤도회로 구성요소의 기능저하를 사전 예측하여 열차의 안전운행을 확보하기 위한 기초자료로 사용되어 질 수 있으며, 차상 검측시스템에서 얻어진 검측데이터와의 비교를 통해 유지보수에 활용 가능한 활용지침 및 분석기준을 작성하기 위해 필요하다.

• 한국산학기술학회논문지
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• 제3권1호
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• pp.63-68
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• 2002

본 연구는 산업용 전력계통에서의 전기 품질을 개선하기 위한 고조파 진단 툴의 개발에 대한 것이다. 이 시스템은 계통의 다양한 운전상태에서 시뮬레이션과 계측을 통한 전기품질 분석에 적합하도록 구성하였다. 시뮬레이션은 PTW(Power Tools for Windows)를 이용하였고, 고조파 측정에는 Dranetz사의 PP-4300 장비가 RS-232를 통해 개인용 컴퓨터와 연결되어 시뮬레이션과 실측 데이터를 비교분석 할 수 있게 하였다. 케이블의 영상분 임피던스 등 미진한 입력자료는 수정된 T&D와 BICC를 이용하였고, IEEE표준 데이터가 변압기 입력자료 측정에 적용되었다. 제안된 시스템은 대규모 실제 산업용 수변전 계통에 적용한 결과 고조파 진단의 유연성과 효율성을 입증할수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 광주전남지부
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• pp.75-78
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• 2006

An external electrode fluorescent lamps (EEFLs) have the advantage of a long lifetime in the early stages of the study on plasma discharge, interest in the lamp continues. Studies on the operation of external electrode fluorescent lamps have focused mainlyon its use of a type of high frequency (MHz). By performing high brightness using a square wave operation method with the low frequency below 100kHz, which is applied to a narrowed tube type lamp that has several mm of lamp diameter, an EEFL presented the possibility of using it as a light source for backlights. However, because an EEFL generates plasma using wall charges, which considers the impedance characteristics of glass based on the structural principle in discharge, it can be significantly affected by frequency. Thus, this study verifies the change in the characteristics of electromagnetic fields according to the change in frequency through a Maxwell's electromagnetic field simulation and examines the relationship between the change in the EEFL frequency and brightness by measuring the optical. characteristics. In addition, the characteristics of the transformation of energy orbits were verified by investigating the characteristics of the wavelength according to the change in frequency through the OES.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.281-284
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• 2004

In Recent, it became necessary to envelope the technology about electrodeless fluorescent lamp according to demand of the electrodeless fluorescent lamp system that used higher efficiency and advantage of long-lifetime. Especially, in the electrodeless fluorescent lamp which used H-mode, efficiency of lamp is decided from matching parameter of antena and inverter So it is of the utmost importance to design antena and inverter. Therefore, this paper used a transformer principle for efficiency rising of electrodeless fluorescent lamp and interpreted an equivalent circuit, used an impedance analyzer in order to confirm a performance enhancement of lamp along design of antenna, and confirmed parameter characteristic of R, L, C, Z, Phase, Q-factor along a change of magnetic flux density. Also, this paper confirmed a luminance characteristic of electrodeless lamp along parameter change with measuring optical characteristic along a change of magnetic flux density.