• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1161-1162
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• 2012

• NEWSLETTER 전기공업
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• no.91-26 s.39
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• pp.1-17
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• 1991

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1614-1616
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• 2011

지중송전라인에서 전압등급의 상승은 선로손실을 줄이면서 밀집된 전력수요에 대응하거나 특별히 고전압 수요를 맞추기 위한 것으로 이것은 XLPE Cable의 제조기술이 향상되면서 지속적으로 진행되어온 초고압송전계통의 일반적 추세이다. 이러한 경향으로 해외에서는 케이블 도체의 송전용량을 증대시킬 수 있는 방법으로 케이블 도체에 에나멜 코팅을 하여 집합을 한다. 그러므로써 기존 케이블에서 발생되는 표피현상 및 근접효과에 의한 AC 저항 요소를 줄여 요구하는 전류용량을 기존 비소선절연 케이블에 비해 더 많이 송전할 수 있다. 하지만, 소선절연 케이블이 전류 용량을 증대 시킬 수 있는 장점은 있으나 접속재의 경우 도체의 에나멜 코팅을 제거해야 하는 문제점이 있다. 당사는 에나멜 코팅을 제거하는 방법을 개발 완료함으로써 본 접속재의 개발을 앞당길 수 있었다. 당사는 쿠웨이트 400kV MEW/C/3931 Project에 400kV XLPE 1C${\times}$2500SQ 소선절연 초고압송전라인을 적용하였는데 본고에서는 여기에 적용된 400kV XLPE 1C${\times}$25000SQ 소전절연 케이블 부속재의 신뢰성을 높이기 위한 설계방법, 시험 및 시공에 대하여 요약하였다.

• Journal of the Korean Magnetics Society
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• v.24 no.3
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• pp.76-80
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• 2014

Toroidal cores made of metallic powder requires large magnetic field strength up to few decade kA/m to obtain major hysteresis loop. To overcome thermal heat generation problem from large exciting current during measurement, we have employed a real time hysteresis loop tracer which can digitize and calculate B-H signals in personal computer as real time. For example, when we magnetize specimen at 10 Hz frequency, we could display hysteresis loops 10 times per second. Using the real time hysteresis loop tracer, we could measure major hysteresis loop of toroidal shape metallic powder core at maximum flux density or maximum magnetic field strength to be measured within 5 second not to significant increasement of specimen temperature due to the heat dissipation from coil windings. For the constructed hysteresis loop tracer, we could measure hysteresis loop at magnetic field strength higher than 50 kA/m for the toroidal shape specimen.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.2
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• pp.61-68
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• 2004

Electric stimulation of teeth has been used for assessing pulp vitality. The principle is based upon the assumption that a subject feels the pain produced by electrical current stimulation of intradental nerve. Because of very high and wide range of impedance of the enamel, it is very difficult to determine stimulation levels regardless of teeth status. Most pulp testers adopt voltage stimulation method and thus, their stimulating threshold levels significantly depend on each individual. Therefore, a constant current stimulator is necessary to minimize the effect of wide variation due to different enamel thickness. And it is also necessary to test teeth vitality with a wide current range regardless of tooth impedance. In this study, we constructed a burst-wave type pulp tester to reduce the pain using a current stabilizing circuit with the maximum current of 150 uA.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.151-151
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• 2009

A enameled wire may have better corona-resistance when its coating material contains nano-sized inorganic particles. However, industrial applications are still limited because an aggregation between nanofillers may happen during coating processes. In this study we use a novel scheme of surface modification with silane on silica nanoparticles using sonochemical reaction where composition and surface density of silanes can be controlled in order to reduce particle-particle attractive interaction. Functionalized nanoparticles are evenly dispersed in the matrix confirmed by SEM and energy dispersive x-ray analysis. Dielectric strength and thermal resistance of the nanocomposite wires are improved while flexibility of the wire maintains.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.10
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• pp.1712-1720
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• 2016

AC and DC insulation breakdown voltage was studied for magnet wire coated with double layers of high flexural PAI layer and high anti-corona PAI/nanosilica (15 wt%) layer. The specimens were prepared at various drying temperatures (T/D): $22^{\circ}C$, $240^{\circ}C$, and $260^{\circ}C$, respectively. The increase effects of nanosilica on AC and DC insulation breakdown voltage were not so significant compared to that of magnet wire coil coated with original PAI. And the AC and DC insulation breakdown voltage was improved by decreasing diameter of winding coil. As T/D temperature increased, AC and DC insulation breakdown voltage decreased.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.123-125
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• 2008

Enamel layer consists of carbonated hydroxyapatite of 85%, water of 12% and protein of 3% and lipid and tentin consists of carbonated hydroxyapatite of 47%, water of 20% and protein of 33% and lipid so if heat is increased in teeth and then teeth color is discolor. In case high temperature is applied in teeth, teeth color changed quality is measured about change of time for minimize teeth change of color. Spectroscopic light intensity special quality by change of time rise at specification temperature.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1903-1904
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• 1997

This paper was dealt with the experiments of the traverse flow and excited CW $CO_2$ Laser. The discharge and laser output characteristics of CW $CO_2$ laser has been investigated. A stable resonator was adopted for the power extraction from the length of 0.9m discharge region with the gap length of 15mm. The maximum output power of about 100W was obtained at the first experiment with the total filling pressure of 30torr, $CO_2$ : $N_2$ : He = 1:3:16.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.12
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• pp.829-834
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• 2016

Coil specimens were prepared by continuous coating on a copper wire with flexible PAI (polyamideimide) and PAI/nanosilica (5 wt%) varnish and thermally aged at 150, 200 and $250^{\circ}C$ for 5, 10 and 15 days, respectively. AC insulation breakdown voltage was investigated under inverter surge condition at 60 Hz and 1,000 Hz and insulation breakdown voltage decreased with increasing aging temperature and aging time at each 60 and 1,000 Hz.