• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권12호
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• pp.620-625
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• 2004

In this paper, we studied the emissive electric field due to the communication signal and the noise in medium voltage power-line. There are many types of conductive noise in power-line channel, which gives rise to radiation. And if the DMT carrier signal was excited, the current by this term was added to the current by noise and, generate radiation. We calculated input impedance by means of signal input network model of medium voltage power-line channel for calculating these currents. We calculated currents by input impedance and, calculated the emissive electric field by this calculated currents. From the measurement results, we knew that the measured results are very similar to the calculated results and if the input signal power level was higher than -40 dBm, the emissive electric field exceeds FCC radiation limit level 69.5 dB$\mu$V/m.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.968-971
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• 2002

Two decisive mechanisms of the electrorhological polishing for a small part(for example, a aspherical surface in a micro lens) are explained. Firstly, non-uniform electric field generated in the polishing structure increases a shear stress of ER fluids which is maximized dramatically near the tool, therefore, substrate adjacent to the tool can be removed effectively by mixed abrasives in the ER fluid. Secondly, abrasives in a non-uniform electric field are governed by the dielectrophoretic phenomena. Abrasives move toward the tool because the field gradient is highest near the tool and then abrasives are actively holded in that area. This phenomena is observed and evaluated by the optical measurement.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1871-1873
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• 1997

The conventional current transformers are often take faults and out of order that for detect to over current of electric power lines because electromagnetic interference. But, it is possible to implement protection relay of high reliability using optical magnetic field sensor which are immunity and small size. The optical magnetic field sensor is possible to rapidly detect to over current and recover when electric power line have fault. And it is not necessary to make with capacitance of electric power lines as optical magnetic field sensor is have linearity from 0 to about 20kA. In this study, we designed and constructed compensative feedback circuit in order to minimize of optical power intensity variation with environ- mental variations(temperature, drive current) of light source. And this system have highest optical advantages and reliability.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 A
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• pp.97-99
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• 1997

For two decades and more, a lot of research work on the biological effects of EMF (Electromagnetic Field) on human health have been reported. Electric facilities in a typical substation are the main source of magnetic field. This paper presents the measurement and analysis of magnetic field in 345/154KV outdoor substation. The magnetic field depends on the currents which distributed by electric facilities. The result of this paper will be able to be used as basic informations to reduce the level of EMF from the electric utility facilities.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.177-180
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• 2006

This study is to make a basic study if solid zinc (Zn) can be used for buried reference electrode, so we examined the adequacy of zinc as reference electrode by using zinc which showed regular electrode for buried period. The deference of electric potential if zinc electrode for corrosion factor such as soil resistivity or pH didn't show fixed trend and there was no clear trend on the change of measurement period. From field test, it is known that the natural electric potential difference of CSE electrode and zinc electrode is 1,100mV, but the electric potential of zinc electrode for CSE electrode in the natural soil and copying soil was 1,094~1,158mV. There was no fixed trend on the change of measurement period and electric potential difference of zinc electrode for corrosion factors such as soil resistivity or pH. Consequently, there was 40~60mV of electric potential difference in every copying soil during the experiment measurement.

• 센서학회지
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• 제10권4호
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• pp.250-258
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• 2001

본 연구에서는 지상에서 전장의 세기를 측정하는 것에 의해 낙뢰 예측이 가능한 뇌경보시스템을 개발하였다. 뇌경보시스템은 전장센서로써 회전형 필드밀, 임피던스변환기, 2단 증폭기 및 마이크로프로세서로 구성되어 있다. 교정 실험결과로부터 뇌경보시스템의 주파수대역과 최대 분해능은 각각 $DC{\sim}200\;[Hz]$, 73[V/m]이었으며, 뇌운에 의한 대지전장의 세기를 18.7 [kV/m]까지 측정할 수 있음을 확인하였다. 실제 상황에서 본 뇌경보시스템의 감지능력을 평가하기 위하여 뇌운의 모델을 이용한 컴퓨터 시뮬레이션을 수행하였으며. 그 결과 관측점으로부터 6 [km] 이내에 접근하는 뇌운의 움직임을 관측할 수 있었다.

• Journal of Magnetics
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• 제12권4호
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• pp.156-160
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• 2007

In this paper, we analyze the errors associated with magnetic field interference for fiber-optic current sensors working in a three-phase electric system and provide a solution to compensate the interference. For many practical conductor arrangements, the magnetic filed interference may cause errors unacceptable for the accuracy requirements of the sensors. We devised a real time compensation method for the interference by introducing geometric and weight factors. We realized the method using simple electronic circuits and obtained the real time compensated outputs with errors of ${\pm}1%$.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 춘계학술대회
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• pp.179-182
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• 1995

Although air, water, and noise pollutions have been widely recognized, electromagnetic forces(EMF) hazard has been rarely recognized as a pollution and very little studies has been done in this country. Thus, in this study electromagnetic forces radiated by various home appliances, once machines, and communication equipments were measured and so were several places radiating strong EMF such as subway stations and electric substations. Among the home appliances microwave oven senates lots of magnetic field and microwaves, and electric mattress does strong magnetic field. In video game room strong magnetic and considerable electric fields were measured. It was observed strong magnetic field inside of electric powered train and very strong magnetic and electric fields on some platforms. Hand-phone and car-phone radiate very hazardous level of microwaves to brain and that they rapidly come into wide use. In this study data base for various electric machines and places radiating strong EMFs were constructed and could be used for future epidemiological studies.

• 조명전기설비학회논문지
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• 제12권3호
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• pp.14-21
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• 1998

본 논문에서는 평판형 전장센서와 멀티턴 루우프형 자장센서를 이용하여 2회선 345[kV] 송전선로에서 발생하 는 극저주파 영역(ELF)의 전장과 자장의 값을 측정하고, 이들의 크기를 3차원 그립으로 나타내었다. 또한, 자장 은 부하전류에 비례하므로 부하변동에 따른 자장의 값올 예측할 수 있도록 그 송전선로의 대표적인 일부하 전류 곡선을 나타내었다 선로 중심점으로부터 횡방향 거리에 대한 측정값을 FIELDS 프로그램에 의해 계산된 이론 값과 비교하였다. 전장의 세기는 송전 철탑 내부와 주변에서 낮게 나타났고, 자장의 경우 최대값이 나타난 지점 은 중부하 회선쪽으로 이동하였으나, 대체로 철탑의 중심부분에서 최대치가 나타나는 경향을 보였다. 송전철탑 주변에서 최대 전장과 자장의 값은 각각 3.5[kV/m]와 $20[{\mu}T]$ 를 초과하지 않았으며, 본 연구에서 측정된 전장과 자장의 값은 관련 여러 국제기관에서 제시한 제한.권고치를 만족시키고 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1331-1333
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• 2001

In this study a measurement equipment was designed and made for the nonlinear dielectric constants in dielectrics. The determining method of the nonlinear dielectric constants also was proposed. The measurement equipment was consisted of the wave generation part, the high voltage amplifier part, the measurement part and the data acquisition part. In this equipment the measurement control and the data processing could be conducted by computer. In order to determine the nonlinear dielectric constants alternating sign-wave electric fields are applied to dielectrics with different magnitude and the waves of the electric fields and the response from dielectrics are stored in computer memories. The harmonics of dielectric displacement are obtained by the Fourier transformation of these waves. The nonlinear dielectric constants are determined at the relatively low-field region. The experiment for PZT ceramic samples was done by the equipment and the determining method and as the result meaningful data were obtained.