• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.2
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• pp.149-154
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• 2012

The size and distribution of welding residual stress and welding deformation in welding structures have an effect on various sorts of damage like brittle failure, fatigue failure and stress corrosion cracking. So, research for this problem is necessary continuously. In this study, non-destructive technique using laser electronic speckle pattern interferometry, plate of welding specimen according to the external load on the entire behavior of residual stress are presented measurement techniques. Once, welding specimen force tensile loading, using electronic speckle pattern interferometry is measured. welding specimen of base metal and weld zone measure strain from measured result, this using measure elastic modulus. In this study, electronic speckle pattern interferometry use weld zone and base metal parts of the strain differences using were presented in residual stress calculated value, This residual stress value were calculated by numerical calculation. Consequently, weld zone of modulus high approximately 3.7 fold beside base metal and this measured approximately 8.46 MPa.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.1
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• pp.1-8
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• 2008

The object of this study is to develop the examination technique for measuring the O-ring deformation behavior under the pressure and the squeezed condition simultaneously. The O-ring deformation measuring device in which two grooves were dug to insert the two O-rings was manufactured to be not deformed under the high pressure and the 1 mm and 0.1 mm gap were designed to measure the extrusion lengths under the internal pressure. The beam hardening correction, the histogram analysis and the dead zone correction were executed to exactly measure the shape of O-ring deformation and the lengths of the O-ring deformation were measured by the LSF and the ERF. The computed tomography applied the pressure of 0, 1.378, 4.902, 9.804, 15.692 MPa at 22.3% squeezed condition and the expanded diameter, contact length and extrusion depth were measured in each pressure. The shape of O-ring deformation was evaluated by the FEM to verify the results of measuring by the computed tomography and the area of O-ring was mutually compared to the area measured by the computed tomography.

• ETRI Journal
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• v.13 no.2
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• pp.54-61
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• 1991

에피택시층의 두께는 푸리에변환적외선분광분석(FTIR)을 이용하여 간단하고 비파괴적으로 측정할 수 있음이 알려져 있다. 본고에서는 측정법의 기본적인 배경을 살펴보고 실제 시편의 측정결과를 제시하며 본 두께 측정법의 적용 가능성 및 문제점에 대해 논의한다.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.4
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• pp.361-367
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• 2013

Many of the nuclear power plant pipe is used in high temperature and high pressure environment. Wall thinning frequently caused by the corrosion. These wall thinning in pipe is expected gradually increase as nuclear power become superannuated. Therefore there is need to evaluate wall thinning in pipe and corrosion defect by non-destructive method to prevent the accident of the nuclear power facility due to pipe corrosion. Especially for real-time assessment of the wall thinning that occurs in nuclear power plant pipe, the laser ultrasonic technology can be measured even in hard-to-reach areas, beyond the limits of earlier existing contact methods. In this study, the optical method using laser was applied for non-destructive and non-contact evaluation. Ultrasonic signals was acquired through generating ultrasonic by pulse laser and using laser interferometer. First the ultrasonic signal was detected in no wall thinning in pipe, then a longitudinal wave velocity was measured inside of pipe. Artificial wall thinning specimen compared to 20, 30, 40 and 50% of thickness of the pipe was produced and the longitudinal wave velocity was measured. It was possible to evaluate quantitatively the wall thinning area(internal defect depth) cause it was able to calculate the thickness of each specimen using measured longitudinal wave velocity.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.5
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• pp.532-537
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• 2004

FEF(Focused Electromagnetic Field) technique was newly developed that is based on the induction principle exciting electromagnetic field. The technique consists of an induction wire and a sensor for detecting electromagnetic field, and is applied in a non-contact mode. In this study, the technique was applied to the evaluation of EDM slits in some conductive materials - aluminum alloy, stainless steel and Inconel alloy. The voltage in the non-defect region is depended upon the measurement lift-off. The voltage signals on defects are measured with peak values, and the peak values changed with the depth of defects. The voltage distributions for all conductive materials are the same trend.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.5
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• pp.341-348
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• 2015

Active infrared thermography methods have been known to possess good fault detection capabilities for the detection of defects in materials compared to the conventional passive thermal infrared imaging techniques. However, the reliability of the technique has been under scrutiny. This paper proposes the lock-in thermography technique for the detection and estimation of artificial subsurface defect size and depth with uncertainty measurement.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.2
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• pp.107-115
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• 2003

Nondestructive testing was carried out in order to evaluate the structural integrity and construction quality of the slurry wall of the underground LNG storage tank. 9 test points were selected, and the wall thickness, rebar spacing, and compressive strength of the slurry wall were evaluated by stress wave impact-resonance method, GPR, sonic velocity, and rebound testing, respectively. As results, the wall thickness, rebar sparing and estimated compressive strength satisfy the design criteria.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.10
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• pp.1595-1600
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• 2013

In the present study,effect of natural mulbelly leaf tea on DMEM MDCK cell line. Mulbelly leaf teas inhibited the proliferation in primery MDCK cells in a dose dependent manner. These results show that mulbelly teas potent inhibits the reactive oxygen species (ROS) and not destruction a component. Therefore, mulbelly teas might improve overall quality of the color and taste. And might be applied newly to development of componant mulbelly teas quality and biochemical change by ROS in living things.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.2
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• pp.163-168
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• 1989

In this paper, Rayleigh wave velocity has been measured by detecting the backscattered signal generating near the Rayleigh critical angle in the elastic medium. The rotating system has been made for the measurment of Rayleigh angle. It has been shown that the measured velocity for the stainless steel, brass aluminum, copper has been good agreement with the theoretical value. The method of non-destructive evaluation using backscattering signal has been presented and the c-scan acoustic image for internal of IC sample has been displayed.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11b
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• pp.769-774
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• 1996

DUPIC 공정은 재처리공정과는 달리 공정의 전ㆍ후를 통하여 사용후핵연료의 양이 변하지 않기 때문에 시설이 원활히 운전되기 위해서는 사용후핵연료가 결손 또는 전용되지 않았음을 증명할 수 있어야 한다. 따라서, 핵투명성(nuclear transparency)을 보장할 수 있는 DUPIC 핵연료 보장조치용 비파괴측정 장치의 개발이 요구되었으며 $^3$He tube, 폴리에칠렌(CH$_2$)감속재, 텅스텐 차폐체 그리고 PSR(portable shift register) 등으로 구성된 측정 시스템을 제작하였다. 본 장치를 사용하여 사용후핵연료에서 검출되는 중성자중에서, $^{244}$ Cm의 자발핵분열중성자 수를 분석할 수 있으며 이를 이용하여 사용후핵연료를 계량관리 할 수 있다. 현재 측정시스템에 대한 성능시험등을 수행하고 있는 중이며 향후 DUPIC 연구용 고준위방사성물질취급시설(hot-cell)에 설치할 예정이다.