• Corrosion Science and Technology
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• 제13권4호
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• pp.125-129
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• 2014

Shinning spot defects on galvanized steel sheets were studied by optical microscope, scanning electron microscope(SEM), Energy Dispersive Spectrometer (EDS) and Laser-Induced Breakdown Spectroscopy Original Position Statistic Distribution Analysis (LIBSOPA) in this study. The research shows that the coating thickness of shinning spot defects which caused by the substrate defect is much lower than normal area, and when skin passed, the shinning spot defect area can not touch with skin pass roll which result in the surface of shinning spot is flat while normal area is rough. The different coating morphologies have different effects on the reflection of light, which cause the shinning spot defects more brighter than normal area.

• 한국신뢰성학회지:신뢰성응용연구
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• 제15권4호
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• pp.276-281
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• 2015

Purpose : The purpose of this study is to propose that domestic rail must the work to be done in the RCM system and railway operators are to present a direction to establish the efficient and systematic system based on this. Methods : In recent years, domestic railway accidents has decreased year rapidly every year. In particular, suicidal ideation was greater than 50% of the accidents is showing a larger decrease in the influence of the screen-door construction. However, the train delay has been maintained without major changes since 2010. The most important cause of the delay operation is a vehicle breakdown. This fact demonstrates that effective maintenance of the most important activities in the railway accident prevention activities. So we have to build a RCM system in which the characteristics of the domestic railway accident. Conclusion : We proposed what is necessary functionality and the function requires a railway operators in RCM railway systeml.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 추계학술대회 논문집
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• pp.349-352
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• 2007

It is impossible to database(DB) the patterns of cable events and cause analysis of faulted cable because the product liability(PL) law have been enforced in Korea, since 2002. In additions, simulation and pattern of cable events are needed for DB system under accelerated deterioration. In this paper, we tested for resistance to nicking of cable below the 22.9kV class due to thermal stresses. This method of exam is following IEC 60811-3-1(Common test methods for insulating and sheathing materials of electric cables). First of all, set the cable in the thermal stress instrument, temperature changed from -20 degree to 120 degree. After thermal stress, we observed a surface crack of cable through microscope and carried out AC withstand voltage test.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.547-549
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• 2004

This system is monitors the degree of aging happened at the electric machine. It detects electromagnetic wave generated from the insulator when the voltage is applied to the machine. By analyzing the internal and external factors make the electric, mechanic, or thermal characteristics of the electric machinery deteriorate the electric insulation and eventually cause the partial electric discharge. The continuous partial electric charge accelerates the insulation aging and the insulation breakdown happens at last. This system consists of the relays connected with 10 sensors (40 total) detecting the partial electric discharge ans the temperature, the server, ans the program analyzing and storing the data.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.232-234
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• 1996

As a building is getting large-scale, composition and intelligence, it is required the stability of building electrical facilities. And it is very difficult of rapidly repair on a breakdown of building electrical facilities. Therefore high-reliability and efficiency of building safety is required. And thus, this study presents the repair-maintenance support program for preventive maintenance on a builing electrical facilities. This program makes offer some functions, facilities history input mode, checking and result mode. User can be made offer the cause and effect information of facilities-faults by this preventive maintenance program.

• 대한한의학원전학회지
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• 제22권2호
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• pp.107-126
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• 2009

King Seonjo, the second son of King Jeongjo, is the twenty-third King of the Joseon Dynasty. He suffered mainly from spleen-stomach weakness syndrome[脾胃虛弱], neurasthenic neurosis and abscess according to the Annals of the Joseon Dynasty[朝鮮王朝實錄]. He experienced chicken pox at the age of twelve, measles at thirteen, smallpox at sixteen. In his twenties he was ill with chronic breakdown due to the spleen-stomach weakness[脾胃虛弱], accompanied by neurasthenia. Abscess occurred during his twenties and the septicemia induced by abscess worsening led him to death. Most treatments were herb-extract medication taken orally, and to some extent ointment care was applied as a cure for abscess.

• 조명전기설비학회논문지
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• 제21권9호
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• pp.18-24
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• 2007

When faults occur in the power equipment that is used a great deal in industrial sites, it may lead to fatal accidents that cause losses both economically and in manpower. In this paper, the effect of particle impact on the partial discharge of $SF_6$ gas was measured by simulating a partial discharge following the type of fault found in the GIS using $SF_6$ insulating gas as the insulating material. A spectrum analysis was performed on the radiate electromagnetic waves emitted upon partial discharge by using the UHF insulation diagnosis method. This subject of this study is insulation diagnosis by the measurement of radiate electromagnetic waves when particles exist in the GIS and power equipment insulated with $SF_6$ gas.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.907-910
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• 1992

This paper deals with the mesurement and the analysis by means of EMTP simulation for the fast-rising switching surges. The fast-rising surges having up to 180ns of front time and 3.42 p.u of peak value were measured at the 154KV substations. The fast-rising surges are expected to cause electric breakdown because the penetrating surges to the transformers result in the higher stress in the winding end than the average stress along the winding.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.179-182
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• 1988

This study is to investigate the adhesive strength of composite material's interface on the experimental methode of tree growth in the material. The results are as fellows 1) The irradiations of ultrasonic energy cause the mechanical vibration in the polymer composite materials of fluid state, so then bring about physical dispersion and heat form inorganic materials, being supposed to produce chemical crosslinking reaction, decreasing of voids between filler and matrix. 2) The characterics of the breakdown are increased by using coupling agent in the composite material. 3) As the intensity of ultrasonic energy and its irradiated time are larger, the tree inception and break-down voltages increase and the tree growing is slower. so we obtain that the interface adhesive force tan be strengthened by the irradiation of ultrasonic energy.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.346-349
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• 1997

It is well known that water treeing is one of the main cause of breakdown in underground power cables, but water tree is not easy to observe. This aging phenomenon was resulted in effect of water and electric field and so on. In this paper, Distilled water was used as water electrode to observe the water treeing in XLPE(cross-linked polyethylene). To observe easily, sample was made of pallet types so water tree was able to show by microscope. As a result, electrical tree appears at niddle electrode tip which was concentrated electric field, but water tree was shown up different types that were appealed in total area of water electrode as well as water electrode tip.