• Journal of Magnetics
• /
• v.15 no.4
• /
• pp.204-208
• /
• 2010

Local wall thinning in pipelines affects the structural integrity of industries like nuclear power plants (NPPs). In the present study, a pulsed eddy current (PEC) differential probe with two excitation coils and two Hall-sensors was fabricated to measure the wall thinning in insulated pipelines. A stainless steel test sample was prepared with a thickness that varied from 1 mm to 5 mm and was laminated by plastic insulation to simulate the pipelines in NPPs. The excitation coils in the probe were driven by a rectangular current pulse, the difference of signals from two Hall-sensors was measured as the resultant PEC signal. The peak value of the detected signal is used to describe the wall thinning. The peak value increased as the thickness of the test sample increased. The results were measured at different insulation thicknesses on the sample. Results show that the differential PEC probe has the potential to detect wall thinning in an insulated NPP pipelines.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.26 no.6
• /
• pp.403-410
• /
• 2006

Eddy current testing (ECT) signals produced by a differential bobbin coil probe vary according to probe design parameters such as the number of turns, geometry and coil gap size. In the present study, the characteristics of a differential bobbin coil probe signals are investigated by numerical simulation in order to determine the optimum coil gap. For verification of numerical simulation accuracy, a specially designed bobbin probe of which the coil gap can be adjusted is fabricated and a series of experiments to acquire signals from two kinds of standard tubes with the variation in coil gap is performed. Then, the experimental signals are compared to the simulation results. Based on this investigation, a decision on the optimum range of coil gap is made. The theoretically predicted signals agree very well to the experimental signals. In fact, this excellent agreement demonstrates a high potential of the simulation as a design optimization tool for ECT bobbin probes.

• The Korean Journal of Zoology
• /
• v.37 no.2
• /
• pp.240-248
• /
• 1994

골격근 세포는 미분화 단핵 근원세포로부터 신장과 융합을 거쳐 다핵 횡문근섬유로 분화되어 가며 동시에 근특이 유전자의 발현이 선택적으로 일어난다. 본 연구에서는 계배 배양 근원세포의 분화동안 유전자 발현 조절 양상에 대한 연구를 위해, 계배 근원세포를 72시간 배양한 근섬유로부터 CDNA 라이브러리를 제작하였다. 이 cDNA 라이브러리를 미분화 단핵 근원세포(배양 36시간)와 분화된 다핵 근섬유(배양 72시간)의 poly(A)+ RNA 주형에서 합성된 [32P〕cDNA를 Probe로 사용한 differential plaque hybridization 방법으로 스크리닝하였다 분화된 다핵 근섬유 CDNA probe에 강한게 흔성화되는 CDNA clone을 선별하여 클로닝하였다. 선별한 CDNA clone 들 중 하나는 약 1.3 Kb 크기의 삽입절편을 갖고 있는 것으로 나타났고, 이 CDNA를 probe로 사용하여 northern blotting 한 결과, 이 CDNA엑 대한 유전자는 미분화 단핵 근원세포에서 분화된 다핵 근섬유로 분화가 진행됨에 따라 유전자 산물인 RNA 양이 증가되는 것으로 나타났다 또한 이 1.3 Kb CDNA에 대한 RNA의 크기는 약 2 7 Kb로 확인되었다.

• Biomedical Science Letters
• /
• v.10 no.2
• /
• pp.75-84
• /
• 2004

Massive identification of differentially expressed patterns has been used as a tool to detect genes that are involved in disease related process. We employed circular single stranded sense molecules as probe DNA for a DNA chip. The circular single stranded DNAs derived from 1,152 unigene cDNA clones were purified in a high throughput mode from the culture supernatant of bacterial transformants containing recombinant phagemids and arrayed onto silanized slide glasses. The DNA chip was examined for its utility in detection of differential expression profile by using cDNA hybridization. Hybridization of the single stranded probe DNA were performed with Cy3- or Cy5-labeled target cDNA preparations at $60^\circ$C. Dot scanning performed with the hybridized slide showed 29 up-regulated and 6 down-regulated genes in a cancerous liver tissue when compared to those of adjacent noncancerous liver tissue. These results indicate that the circular single stranded sense molecules can be employed as probe DNA of arrays in order to obtain a precious panel of differentially expressed genes.

• Journal of the Korean Magnetics Society
• /
• v.15 no.5
• /
• pp.292-297
• /
• 2005

Steam generator of a nuclear power plant has important rolls for the heat transfer and the isolation of radioactive materials. So bursting of the steam generator tube is directly related to the accident of nuclear power plants. Incone1600 has been used for the steam generator tube material. The material shows non-magnetic and metallic properties, eddy current NDT method has been employed for defects detection. In this work, a differential type of eddy current probe was developed to improve resolution of defect detection. To verify properties of the developed differential type eddy current probe, we have made reference material with SUS304 which has similar magnetic and electrical properties of Inconel600. Using the developed differential type eddy current probe, we can detect defect size of 0.25 mm in diameter and 0.2 mm in depth (volume of $1{\times}10^{-3}\;mm^3$) with the reference material.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.21 no.5
• /
• pp.561-564
• /
• 2001

The cladding area of HANARO Research Reactor fuel rods should be checked not to have any defects larger than the size required at QA documents by using eddy torrent testing method doting fabrication process. To apply eddy current testing inspection to the fuel rods, encircling differential probes and standard specimen were designed and fabricated. The impedance of the fabricated probes was measured with impedance analyzer in order to cheek that the probe has a suitable impedance for the inspection frequency, and with this probe and MIZ-40A eddy current equipment, the detectability of this probes was investigated. The developed probes could detect artificial notch with 2mm length 10% depth of cladding thickness in cladding area. In addition, the probe was successfully applied to detect the defects in cladding area doting fabrication of the research reactor rods.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.27 no.2
• /
• pp.89-96
• /
• 2007

The bobbin probe examination is basic and the important method among other ECT techniques for the steam generator tube integrity assesment that is practiced during each plant outage. The bobbin probe is one of the essential components which consist of the whole ECT examination system, and provides us a decisive data for the evaluation of tube integrity in compliance with acceptance criteria described in specific procedures. The selection of examination probe is especially important because the quality of acquired ECT data is determined by the probe design characteristics, such as geometry and operation frequency, and has enormous effects on examination results. In this study, An optimal differential bobbin probe is designed for the steam generator tube inspection in nuclear power plants(NPPs). Based on the test results for electrical and ECT signal characteristics, the prototype bobbin probe satisfies all the criteria.

• The Journal of Natural Sciences
• /
• v.12 no.1
• /
• pp.49-59
• /
• 2002

Exponential decrease of saturation absorption signal was reported in pump beam spacially keeping off from probe beam. Optimum angle between pump beam and probe beam in the differential-velocity-selective saturation absorption spectroscopy was computed theoretically, $1.33^{\circ}$ in cesium atoms and $1.08^{\circ}$ in Rb 87 atoms, and was good agreement with the experimental results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.06a
• /
• pp.398-399
• /
• 2009

본 논문에서는 XLPE 전력케이블 접속부의 부분방전을 측정하기 위한 Ferrite 형상에 따른 EM Probe를 설계하였다. 부분방전 펄스의 검출대역를 넓이기 위해 투자율이 2400인 페라이트코어를 사용하여 센서를 제작하였고 형상에 따른 특성을 비교하기위하여 실린더형 Ferrite와 말굽형 Ferrite를 적용하였다. 또한 부분방전 검출능력을 확인하기 위해 상용 HFCT센서의 비교 실험을 통하여 위상특성과 주파수 특성을 분석하였다.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1998.10a
• /
• pp.302-302
• /
• 1998