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원전 저압케이블 열화도 평가를 위한 초음파 음속계측에 관한 연구
김경조,강석철,구철수,김진호,박재석,주금종,박치승 한국비파괴검사학회 2004 한국비파괴검사학회지 Vol.24 No.4
원자력발전소에는 여러 종류의 케이블이 전력공급, 감시 및 제어신호의 전달을 위해 열악한 환경하에서 이용되고 있다. 발전소의 안전한 운전을 위해서 이 케이블이 어느 정도 열화 되었는지 확인할 필요가 있다. 특히, 원자력발전소의 수명 연장과 더불어 저압 케이블을 장기간 사용함에 따라서 저압케이블의 열화를 평가하기 위한 방법이 필요하게 되었다. 저압케이블의 열화를 측정하는 파라미터로는 주변 온도, 절연재질의 경도, 파단시 연신률(EAB, Elongation At Breaking Point)등이 있다. 그러나, 온도나 경도를 계측하는 검사는 정량적인 판단기준의 설정이 곤란하고 진단의 정밀도가 낮으며, 부분적으로 샘플링하는 방법은 샘플링되는 케이블에 연결된 부하를 정전시켜야 하고 장소와 시간적인 제약이 있으며, 전기적 측정법은 노화 초기부터 중기까지의 열화정도를 확인하기 어렵다. 본 연구에서는 재료의 열화에 따라서 초음파의 음속이 변화한다는 이론적인 배경 [1,2]를 바탕으로 저압 케이블 재료의 열화에 따른 초음파의 음속을 측정하였다. 이를 위해, 원자력발전소에서 사용되는 저압케이블을 가속 열화시켰으며, 저압케이블의 피복재에서 초음파의 음속을 측정할 수 있는 장비를 개발하여, 초음파의 음속측정 후 인장시험을 통해 파단시 연신률을 측정하였다. 파단시 연신률이 증가함에 따라서 음속이 선형적으로 감소 하였으며, 초음파의 음속은 열화의 정량적 평가 파라미터로서의 사용 가능성을 확인할 수 있었다. Several kinds of low voltage cables have been used in nuclear power plants for the supply of electric power, supervision, and the propagation of control signals. These low voltage cables must be inspected for safe and stable operation of nuclear power plants. In particular, the degradation diagnosis to estimate the integrity of low voltage cables have recently been emphasized according to the long use of nuclear power plants. In order to evaluate their degradation, the surrounding temperature or hardness is not useful because of the absence of quantitative criteria; the inspection of a sample requires turning off of the power plant power; and, the electrical inspection method is not sufficiently sensitive from the initial through the middle stage of degradation. In this research, based on the theory that the ultrasonic velocity changes with relation to the degradation of the material, we measured the ultrasonic velocity as low voltage cables were degraded. To this end, an ultrasonic degradation diagnosis device was developed and used to measure the ultrasonic velocity with the clothing on the cable, and it was confirmed that the ultrasonic velocity changes according to the degradation of low voltage cables. The low voltage cables used in nuclear power plants were degraded at an accelerated rate, and EAB was measure in a tensile test conducted after the measurement of ultrasonic velocity. With the increasing degradation degree, the ultrasonic velocity decreased, whose potential as a useful parameter for the quantitative degradation evaluation was thus confirmed.
Bile Acid-induced JNK Activation Directly Initiates Mitochondrial Cytochrome C Release
( Geum Youn Gwak ),( Jung Hwan Yoon ),( Kang Mo Kim ),( Hyo Suk Lee ),( Chung Yong Kim ) 대한소화기학회 2003 대한소화기학회 추계학술대회 Vol.2003 No.-
<Background & Aims> In cholestasis, elevated bile acid concentrations within the liver promote liver injury by inducing hepatocyte apoptosis. Bile acid-induced apoptotic process primarily involves death receptor-mediated signaling cascades. Bile acids can
The Epidermal Growth Factor Receptor Signalings in Human Cholangiocarcinomas
( Geum Youn Gwak ),( Jung Hwan Yoon ),( Kang Mo Kim ),( Hyo Suk Lee ),( Chung Yong Kim ) 대한소화기학회 2003 대한소화기학회 추계학술대회 Vol.2003 No.-
<Background & Aims> We have recently demonstrated that bile acids appear to participate in the genesis and progression of cholangiocarcinoma via activation of the epidermal growth factor receptor (EGFR). However, the characteristics of EGFR signaling in c
절임 방법과 소금 종류를 달리하여 제조한 절임 배추의 품질특성 비교
최금혜(Geum-Hye Choi),이가영(Ga-Yeung Lee),봉연주(Yeon-Ju Bong),정지강(Ji-Kang Jeong),문숙희(Suk-Hee Moon),박건영(Kun-Young Park) 한국식품영양과학회 2014 한국식품영양과학회지 Vol.43 No.7
This study compared quality changes among brined baechu cabbages manufactured by various salting methods and types of salt. Brine, brine and dry salting, and dry salting were used as salting methods. When baechu cabbages were salted by dry salting method, the salinity of brined baechu cabbage increased compared to salting by other methods, even though the quantity of salt used was small. In addition, salinities of leaf and stem were relatively equal among brined baechu cabbages using dry salting method compared to those of other methods. When baechu cabbages were salted using dry method at different salt concentrations (3%, 5%, and 10% of weight of baechu), brined baechu cabbage showed suitable salinity (1.41~1.42%) at 5% salt concentration. Among brined baechu cabbages prepared using dry salting method with different types of salt (purified salt, solar salt, and bamboo salt), bamboo salt produced the highest salinity. Brined baechu cabbages with solar salt and bamboo salt showed significantly lower counts of total aerobic bacteria and higher counts of lactic acid bacteria than others. These results indicate that baechu cabbage can be salted equally, and the amount of salt used can be reduced when baechu cabbage is salted using dry salting method. In addition, using solar salt and bamboo salt can increase the quality of brined baechu cabbage.