• Transactions on Electrical and Electronic Materials
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• 제7권5호
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• pp.262-266
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• 2006

The insulation diagnostic test and the AC breakdown test were performed under off-line using the 3.3 kV class induction motor which have been served for 10 years. These tests were conducted in means of nondestructive and destructive test. In this paper, we compared the correlation between the nondestructive and destructive test. Furthermore we setup an experimental condition with moisture and compared the insulation characteristics between moist and dry sample. From the results of the nondestructive and destructive test, it was found that the second AC current, which is the previous step of insulation breakdown, suddenly increased at a point of around 8.5 kV. The insulation breakdown of moist sample occurred at 12-14 kV, which is 4-5 kV lower than dry sample.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.285-285
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• 2009

Due to a development of a modem technology as Power Line Communication(PLC) over 200 Mbps, the high-speed multi-media data trasmission could be currently possible. In This paper we develop a high quality media transmitter-receiver based on merging the HomePlug AV, which is 200 Mbps class PLC technology and HDMI Interface technology. Smart Live 6 software were used for the assessment of audio property. As the result of measurement of the HD class images by capturing from the receiver of the PLC, the quality of images couldn't be confirm any deterioration, which has compared with original reflections. In case of audio part as the result of confirmation of the Phase, Magnitude, it has been confirmed that over 90% of nomal transmition and receiving of acoustic signal.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2118-2122
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• 2005

This test was performed to assess the corelation of insulation deterioration condition with breakdown voltage of the stator winding of 3.3kV class induction motors which have been in service for 10 years after being installed in 1993. The insulation diagnostic tests include resistance, polarization index(P.I), dissipation factor$({\Delta}tan{\delta})$, maximum partial discharges (Qmax) and AC breakdown test. we evaluated the corelation of insulation diagnostic test with AC breakdown test for stator wilding of high voltage induction motor.

• 전기학회논문지
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• 제59권1호
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• pp.192-196
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• 2010

Due to a development of a modem technology as Power Line Communication(PLC) over 200 Mbps, the high-speed multi-media data trasmission could be currently possible. The strength of the PLC has no more additional wiring work. PLC has also possible to high quality data transmission with currently electrical cable. It has a various strong point campare with existing wire and wireless communication technologies. In This paper we develop a high quality media transmitter-receiver based on merging the HomePlug AV, which is 200 Mbps class PLC technology and HDMI Interface technology. The video function was used for the VEDEO TEST GENERATOR in order to a property valuation. Smart Live 6 software were used for the assessment of audio property. As the result of measurement of the HD class images by capturing from the receiver of the PLC, the quality of images couldn't be confirm any deterioration, which has compared with original reflections. In case of audio part as the result of confirmation of the Phase, Magnitude, it has been confirmed that over 90% of nomal transmition and receiving of acoustic signal. It can be possible to have HD class Media service through the PLC.

• KEPCO Journal on Electric Power and Energy
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• 제2권3호
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• pp.421-424
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• 2016

In order to evaluate the insulation deterioration in the stator windings of air-cooled gas turbine generators(119.2 MVA, 13.8 kV) which has been operating for more than 15 years, diagnostic test and AC dielectric breakdown test were performed on phases A, B and C. Diagnostic test included measurements of AC current, dissipation factor, partial discharge (PD) magnitude and capacitance. ${\Delta}I$ and ${\Delta}tan{\delta}$ in all three phases (A, B, and C) of generator stator windings showed that they were in good condition but PD magnitude indicated marginally serviceable condition. After the diagnostic test, an AC overvoltage test was performed by gradually increasing the voltage applied to the generator stator windings until electrical insulation failure occurred, in order to determine the breakdown voltage. Although phase A of generator stator windings failed at breakdown voltage of 29.0 kV, phases B and C endured the 29.0 kV. The breakdown voltage in all three phases was higher than that expected for good-quality windings (28.6 kV) in a 13.8 kV class generator.

• 대한조선학회 특별논문집
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• 대한조선학회 2009년도 특별논문집
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• pp.18-23
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• 2009

After the installation of electric cables at block, PE(pre-erection) and hull stages, the coating stains on the electric cable sheath were unavoidably occurred by additional painting process. According to class rules paint or coating applied on the electric cables shall not adversely affect the mechanical, chemical of fire resistant characteristics of the electric cable sheath. However, there has not been quantitatively studied about the effect of coating stains on properties of sheath materials. In this study, we tried to investigate the effect of coating stains on the performance and deterioration of sheath materials by using FTIR, SEM analysis, flame retardant, high potential voltage and tensile test. The results sowed that coating stains, which were occurred during painting work on site could not adversely affect on the performance and deterioration of sheath materials.

• 한국안전학회지
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• 제30권6호
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• pp.102-109
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• 2015

In this study, on the basis of the results of the field survey and the theoretical consideration for Korean Standard Specification for concrete durability and maintenance, the following conclusions are derived. From the survey, the prediction equation of carbonation depth for the southwest region in Korea is experimentally proposed, $y_p=5.865{\sqrt{t}}$, which predicts about 60mm of the carbonation depth for the concrete structures of 100 years, a 1st class of target endurance period, under a combined deterioration environment like a marine environment. Considering that the marginal value for a carbonation depth limitation under very severely marine environment is 25mm, in accordance with the Specification, it is found that the predicting carbonation depth for the concrete cover depths, 100mm and 60mm are 63mm and 29.4mm, respectively. In conclusion, according to the equation and the Specification, it is strongly required that the reinforced concrete structures with the cover depth under 100mm have to make a protection from combined deterioration factors by any methods like a surface coating, an increment of cover depth or an application of a special concrete.

• 한국환경생태학회지
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• 제9권2호
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• pp.211-220
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• 1996

오대산 국립공원의 5개 주요 등산로에 대해 이용강도에 따른 등산로 및 주변 환경훼손상태를 조사하였다. 총 22km, 120개 지점에서 등산로 상태를 조사한 바 등산로폭, 나지노출폭, 최대침식깊이 및 등산로물매는 이용강도에 따른 차이가 인정되었다. 훼선유형의 출혈빈도는 뿌리노출, 암석노출, 종침식, 분기 등의 순이었으며 이들 지점의 등산로상태는 건전한 지점과 뚜렷한 차이를 보였다. 등산로 주변의 환경피해도 4등급 이상인 나지의 변적은 전체 379m/km이며, 상원사 등산로가 1,196m$^{2}$/km로서 가장 많이 발생되어 있었다. 주연부 상층식생의 우점종은 신갈나무였고, 하층식생은 사면에서 철쭉꽃, 능선부에서 다래가 우점종이었다. 주연부 하층식생의 피도 및 개체수는 이용강도가 높은 상원사 등산로에서 가장 낮았으며, 등산로간의 하층식생의 종구성은 대체로 이질적이었다.

• 한국수산과학회지
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• 제28권6호
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• pp.770-778
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• 1995

Anchovy Engraulis japonica boiled and dried was stored at $20^{\circ}C$ for 5 months after that treatment of sodium-erythorbate (Na-ery) or deoxygenizer (Deoxy). During storage, peroxide value (POV), thiobarbituric acid (TBA) value, lipid content, and lipid class compositions were determined to evaluate the quality of the samples. pay was decreased rapidly for the first 3 months storage and its decrease was Deoxy group>Control group>Na-ery group in that order. TBA values increased for the first 4 months and then decreased rapidly, and it's increase was the highest in Control group, followed by Na-ery and Deoxy group. Total lipid contents in all samples declined during storage. Especially, phospholipid decreased mainly in Na- ery and Deoxy group, while neutral lipid mainly in Control group. Triglyceride (TG), phosphatidylethanolamine(PE), and phosphatidylcholine(PC) decreased, while free fatty acid (FFA) and lyso-PC (LPC) increased during storage. The decrease of TG was the highest in Control group and that of PE and PC was higher in Na-ery group than in other sample. The decrease of PE in all samples (except Deoxy group) was higher than that of pc. The increase of FFA and LPC were higher in Control and Na-ery group than in Deoxy group. These results indicated that the lipid deterioration of the boiled and dried-anchovy was effectively suppressed by the enclosed deoxygenizer during storage at $20^{\circ}C$.

• 한국환경생태학회지
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• 제7권2호
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• pp.241-251
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• 1994

덕유산 국립공원 등산로 및 야영장과 주변환경의 훼손에 대한 이용영향을 파악하기 위하여 4개의 주요 등산로와 덕유대야영장을 대상으로 1993년에 조사를 실시하였다. 등산로폭, 나지노출폭, 최대 깊이 및 등산로물매는 이용강도에 따른 차이가 인정되었다. 총 28km, 106개 조사지점에서 관찰된 훼손형태는 암석노출, 종침식, 뿌리노출등의 비율이 높았고 훼손된 지점의 등산로상태는 건전한 지점과 뚜렷한 차이를 나타내었다. 백련등산로가 가장 훼손이 심화되고 있으며 환경피해도 4등급 이상의 면적이 910$m^2$/km에 이르며 야영장에서도 이용압력과 훼손이 증가하고 있었다. 주연부의 상층 및 하층수관의 우점수종은 백련등산로에서 졸참나무 및 당단풍, 나머지 등산로에서는 모두 신갈나무 및 미역줄나무였으며, 이용강도의 차이가 있는 등산로간의 하층수종을 비교할 때 당단풍, 졸참나무, 개옻나무, 쇠물푸레나무, 조록싸리, 국수나무, 노린재나무 등이 이용영향에 대한 내성이 큰 수종으로 나타났다.