• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2402-2404
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• 1999

In this study, we measured the PD pattern with multiple voids in PET film. The analysis of PD pattern was employed the statistical factor such like CCF(cross correlation factor), asymmetry, kurtosis and etc. The difference of PD patterns caused by arrangement of voids, even if the same size and numbers of void in PET film. Such result of experiment will be used to know the PD source in the real equipment about arrangement and numbers of the defect in insulator.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.505-508
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• 2005

Concrete has a void, which exists as one of defect in concrete. If the porosity of concrete increases, durability of concrete decreases. In this paper, to improve surface void of concrete, surface penetration sealers are applied to specimen. And it were investigated that the resistances of chloride penetration and freezing and thawing for concrete with surface penetration sealer of two types. According to the results, surface penetration sealer has not show a harmful influence on strength and resistance of freezing and thawing. Also, B type surface penetration sealer was more superior in resistance of chloride penetration.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.241-244
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• 2006

It is essential to develop a large capacity, non-contact nondestructive inspection system having high reliability to investigate repaired and strengthened structures. Nowadays, an infrared camera is widely used in non-contact nondestructive inspection system. Because an infrared camera is sensitive to the surrounding environment, it is necessary to improve a sensitivity of thermal image information and a relationship between defects and thermal image information. In this papaer, presented is an optimum void detection chart for the optimum conditions to detect infrared rays from inside and outside defects like voids and cracks in concrete structures using extensive computer simulation. Sensitivity studies are performed with respect to variables influencing the temperature distribution such as heating temperature, heating time, and geometries of defect, etc. It may be stated that it could be successfully utilized for the non-contact nondestructive inspection system to detect defects in concrete structures.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1624-1626
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• 1999

PD in defect of solid insulation system is very harmful since It often leads to deterioration of insulation by the combined action of the discharge ions bombarding the surface and the action of chemical compounds that are formed by the discharge. PD can indicate incipient failure, so it has been used to determine degradation of insulation. In this paper. we investigated PD in defects of solid insulation by using statical method and classified PD patterns with surface discharge, electrical tree and void discharge by using Kohonen network. we used peak charge, average discharge power, average discharge current, repetition rate, skewness, kurtosis, QN of the max pulse height vs. repetition rate $H_q(n)$ for analysis and classification.

• 전기학회논문지
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• 제61권2호
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• pp.251-256
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• 2012

This study deals with the location of partial discharges(PDs) for power cables and GIS using 2 PD sensors and long coaxial signal cables. Throughout the experiments by use of simulated PD pulses and corona discharges in the power cable system, it is found out that the impedance matching between the coaxial signal cable and the measuring equipment should be done for good S/N ratio and the on-site measurement using more than 100m-long coaxial signal cable is possible. In addition, new PD location algorithm with the polarities of PD pulses and the arrival time difference between two pulses was proposed and was proved through the partial discharge experiments for the cable joint defect and artificial void defect.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.397-398
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• 2009

In oder to investigate of partial discharge of nano-composites materials, we have studied partial discharge appling voltage from 5 to 30 [kV] to make an artificial defect with the epoxy adding to 0, 0.4, 0.8, and 1.6 [wt%], respectively. The experimental result, we have found that $SiO_2$ of 0.4 (wt%] was superior to others also, it is found that the effect of isolate diagnosis to get the slope for the discharged electric charge distribution.

• KIEE International Transactions on Electrophysics and Applications
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• 제2C권5호
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• pp.239-245
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• 2002

In this work, in order to realize the possible defects at the cable joint interface, four different types of artificial defects are provided : conducting, insulating substances, void and scratches. The analysis related to the PD patterns has been performed by means of conventional Phase Resolved Partial Discharge Analysis (PRPDA) and Chaotic Analysis of Partial Discharge (CAPD) as well which was proposed by our previous communication. As a result, it could be pointed out that each defect has shown particular characteristics in its pattern respectively and that the nature of defect causing partial discharge could be identified more distinctively when the CAPD is combined with the conventional statistic method, PRPDA.

• 전기학회논문지P
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• 제57권1호
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• pp.56-59
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• 2008

We have designed 4 types(void in insulation paper, protrusion electrode, floating electrode, surface discharge) of partial discharge(PD) defect to simulate typical faults found in oil filled power transformers. Ultra-high frequency(UHF) radiation due to PD was measured using a UHF measuring system and a conventional PD measuring system, simultaneously. Electromagnetic radiation spectra of these defects show UHF radiation up to about 1.5-2 GHz range. The phase resolved partial discharge(PRPD) patterns of UHF radiation from the PD defects were also measured and the pattern reveals distinct feature for each defect types. The UHF measuring could be used to detect PDs in oil filled transformers and analysis of the PRPD pattern should provide useful information on origin of PD signal.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2007년도 추계학술대회 논문집
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• pp.27-27
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• 2007

Cu via fill 도금 시, void, seam과 같은 내부 defects는 공정 중 신뢰성을 떨어뜨리며, 전기신호 전달속도를 느리게 한다. 또한 Cu via fell 도금 공정 중 발생하는 과도한 Cu 표면 도금층은 wafer thenning 공정의 생산성 저하와 공정 비용 상승을 유발한다. 3D Interconnection용 직경 30${\mu}$m, 깊이 120${\mu}$m (Aspect Ratio : 4) Via를 이용하여 정류방법, 전류 parameter, 첨가제 조성에 따른 Cu via felling 특성과 overburden두께 변화를 실험적으로 검증하였다.

• 비파괴검사학회지
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• 제30권3호
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• pp.271-281
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• 2010

Brazing fitting which is one of the aircraft hydraulic power system components is widely used for saving weight and achieving higher reliability. Any inherent defects or damage of fitting can cause system failure and/or physical damage of human body due to highly pressurized fluid. Radiographic testing(RT) technique and additional micro-structure investigation on cut-away surfaces have been accomplished to find out some defect-like-inhomogeneity in the fittings. The radiography results showed that some defect-like-inhomogeneity existed inside body. Additional micro-structure investigation on cut-away surface reveals that the inhomogeneity is due to internal voids. In this study, it can be is said that RT technique can be a useful tool for field acceptance test of hydraulic brazing fitting in short time.