• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.369-370
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• 2008

This paper describes the electric field distribution of high voltage polymer bushing with inner field shaper designs. The field control can be achieved by means of the designs of such internal field shaper. But high electric stress occurred between field shaper and central conductor by the closely space. In accordance, the floating and ring shield designs was importance for electric stress grading at critical parts of the bushing. The bushing has a central conductor, and internal ring shield or floating shield, gaps are formed between field shaper and ring shield. Accordance equipotential lines extend through gaps. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymer bushing.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권11호
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• pp.616-621
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• 2002

With biological effects by ELF (Extremely Low Frequency) magnetic field generated from power system, the transient magnetic field from electric appliances is a major issue presently. Because the transient magnetic field induces higher current than the power frequency field inside living bodies, transient magnetic field exposure has been much focused. In this paper, it is shown that transient magnetic field from electric home appliances can be characterized as magnetic dipole moment. In this method, the dipole moment vector is assumed by allowing an uncertainty of 6dB in the estimated field. A parameter M that represents biological interaction was applied also. The proposed method was applied to 7 types of appliances (hair drier, heater, VDT, etc.) and their equivalent magnetic dipole moment and harmonic components were estimated. As the results, the useful data for quantifying magnetic field distribution around electric appliances were obtained.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 방전 플라즈마 유기절연재료 초전도 자성체연구회
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• pp.104-108
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• 2004

The effect of magnetic field was measured on NOx removal for cylinder-wire plasma reactor with magnetic field applied to electric field vertically. Power was supplied to plasma reactor using rotating spark gap switch. Consumption power increased with increasing discharge voltage. When magnetic field was applied to electric field vertically, consumption power was less than that without magnetic field because of lorenz's force. NOx removal rate of plasma reactor with magnetic field were higher, 10-15%, than that of plsama reactor without magnetic field. And NOx removal rate decreased with increasing gas flow rate.

• 한국전기전자재료학회논문지
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• 제14권6호
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• pp.491-498
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• 2001

The relationship between electrical properties of YBaCuO superconductor and externally applied magnetic field was studied to develop a magnetic field apolarity sensor. The electrical resistance of the superconductor was increased by applying external magnetic field and even after removal of the magnetic field. The behavior was related to the magnetic flux trapped in the superconductor, which penetrates through the materials by the external magnetic field. Some portion of the superconductor was changed to a normal state by the trapped magnetic flux. The appearance of the normal state yielded to enhance the electrical resistance. Electrical characteristics of the superconductor with trapped magnetic flux were extremely sensitive to the external magnetic field and showed different responses depending on the direction of the magnetic field. Considering the observed properties of the superconductor with trapped magnetic flux, a magnetic sensor was fabricated to detect simultaneously both the intensity and the direction of the magnetic field.

• 한국전기전자재료학회논문지
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• 제30권3호
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• pp.148-151
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• 2017

This research concerns field rings for 3.3kV planar gate power insulated-gate bipolar transistors (IGBTs). We design an optimal field ring for a 3.3kV power IGBT and analyze its electrical characteristics according to field ring parameters. Based on this background, we obtained 3.3kV high breakdown voltage and a 2.9V on state voltage drop. To obtain high breakdown voltage, we confirmed that the field ring count was 23, and we obtained optimal parameters. The gap distance between field rings $13{\mu}m$ and the field ring width was $5{\mu}m$. This design technology will be adapted to field stop IGBTs and super junction IGBTs. The thyristor device for a power conversion switch will be replaced with a super high voltage power IGBT.

• 한국농공학회지
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• 제39권4호
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• pp.64-74
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• 1997

The purpose of this study is to analyze hydraulic characteristics of surface irrigation in a paddy field of direct seeding culture. Field experiment was performed in the paddy field of ridge direct dry seeding. Simulation by a numerical model was also accomplished with the data obtained from the field experiment. The model was developed by one dimensional zero-inertia equation and finite difference method. From the result of the field observation, the furrows of the experimental field were found to have various geometric characteristics. Advance distance and time were measured both in the field and by the model simulation for various furrow lengths and irrigation discharges. Roughness coefficients of each furrow were also estimated by the model.

• 전기학회논문지
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• 제56권5호
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• pp.921-925
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• 2007

Gas removal characteristics of an air clean system, consisted of a filter and a nonthermal discharge plasma reactor with a magnetic field, have been investigated with emphasis on the enhancing gas removal efficiency of the applied magnetic field. It is found that the magnetic field influenced significantly to the corona discharge characteristics, decreasing the corona onset voltage and increasing the corona current. As a result, the proposed air clean system with the magnetic field showed the higher removal efficiency of the gas (e.g., trimethlyamine) than that of without the magnetic field. This would be because the magnetic field applied to the discharge plasma reactor of the air clean system can elevate the corona characteristics, and activate the generation of ozone, thus the removal efficiency of the gas was concurrently enhanced. This reveals that the proposed air clean system with the magnetic field could be used as an effective means of removal an indoor pollutant gas.

• 대한전기학회논문지
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• 제43권6호
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• pp.1001-1009
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• 1994

The present paper deals with a new developed sensor for measuring the time-varying magnetic fields and describes the experimental results of trasient magnetic field that takes place during the operations of electric appliance. The operation principle of the self-integrating magnetic field sensor by using coaxial cable is analyzed and a calibration investigation is carried out. The frequency bandwidth of the magnetic field measurement system is from 40 Hz to about 300 kHz. The magnetic field induced by the starting and/or operation of electric appliance mainly includes the odd harmonics such as the third, the fifth and the seventh harmonics. The magnetic field intensity caused during the operation of ultrasonic washer is inversely proportional to distance, this correspodns to induction component. As a result, it was known that the odd harmonics of magnetic field in the desing of electromagnetic shield employed for protecting electronic circuit and control devices have to be considered.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.279-280
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• 2005

We have designed a single gap transflective liquid crystal display (LCD) driven by a fringe electric field and vertical field. The conventional FFS mode does not have an electrode on top substrate, it shows not only slow response time due to weak electric field but also slow discharging problem when electrostatic field is generated after fabricating the cell. To solve these problems, transflective LCD with ITO coated upper substrate was suggested but the transmittance was reduced significantly due to effects from vertical field. Hence, in the present paper, new transflective LCD with ITO coating only in the reflective region was characterized.

• 대한전기학회논문지
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• 제39권9호
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• pp.964-975
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• 1990

This paper aims at the design of high voltage electrode contour under specified field condition. Defining the contour with B-Spline curve, the number of contour variables can be reduced and very smooth electrode can be obtained. For the analysis of the electric field, Surface Charge Method which has advantages in practical model has been used. As an initial contour, the rod-plane gap has been used since the difference between maximum and minimum field value is relatively large. Various field conditions including uniform field condition are given to the end of the rod electrode. Under uniform field condition, authors designed an electrode whose field-deviation was under 0.5%. Finally, the relation between the curvature and field of the electrode has been checked, which showed that B-Spline curve is appropriate for the shape function.