• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.109-112
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• 1996

The more integrated and smaller SMD are needed, new solder joints packaging technologies are developed in these days such as BGA(Ball Grid Array), Flip Chip, J-lead etc. But, it's unable to inspect solder joints in those devices by visual inspection methods, because they are hided by it's packages. To inspect those new SMD packages, an X-ray system for acquiring a cross-sectional image of a arbitrary plane is necessary. In this paper, an analysis for designing X-ray cross sectional imaging system is presented including the way for correcting the distortion of image intensifier. And we show computer simulation of that system with a simple PCB model to show it's usefulness in applying PCB solder joint inspection.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.117-120
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• 1996

In this paper, a new approach to acquire the cross-sentional image for automatic solder joint inspection of double-sided PCB using X-ray source is presented. We designed the apparatus with fixed X-ray source to realize the cross-sectional image by tunning object and detector synchronously. The cross-sectional images are captured at several view angle of X-ray source, the geometric image distortions caused by view angle and the shape of image intensifier are compensated. The precision variation of cross-sectional image by the change of view angle was investigated. Also we acquired the cross-sectional image to the solder joint of double-sided PCB and reconstructed the shape of solder joint.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.917-921
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• 1991

Hydraulic fitting impulse tester is equipment which produce impulse pressure waveform that specified foreign standard of SAE, JIS etc. Test conditions of SAE J1453 about waveform standard indicates frequency of 35-70 cycle/min, pressure of 560 bar, oil temperature of 93 .+-.3.deg. C etc. and required cycle is a million over. In additions, Test condition operated continuously equipment. This development item adopted new pattern method such as intensifier and rotary distributor is different from already established fitting impulse tester applied servo valve and high pressure direct directional control valve. Therefore, this development item which compares already established item is good reliability, low cost of manufacture and save of electric energy. especially, Domestic small and medium enterprise uses this tester because of economical cause. We develope appropriateness tester which conforms to demand of user.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.3
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• pp.36-42
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• 2000

A fundamental experimental study for an alternative proposal to super-speed craft propulsion system called underwater ram-jet propulsion by high pressure air ejection as driving force was investigated. For basic study of the effects of ram-jet propulsion performance, a simple underwater ram-jet flow field was established and PIV(Particle Image Velocimetry) method was adopted to analyse the jet-induced flow appearing at ram intake, mixing chamber and nozzle. Some flow dynamics relating to the high-speed ram-jet effect were discussed for the basic understanding of the its propulsion principle.

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.302-304
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• 2004

Nuclear fuel elements containing dry recycling nuclear fuel pellets for the irradiation test in a reactor were remotely fabricated from spent PWR fuel materials in a hot cell. End closure welding as well as seal tube welding for thermal sensor of the elements was performed by Nd:YAG laser. The soundness of the end closure welds and seal tube welds for the elements were evaluated by a precise X-ray inspection system composed of a micro-focus X-ray generator with an image intensifier and a real time camera system. Then, helium leak test was performed for the elements. The soundness of the welds of the fuel elements was confirmed by the X-ray inspection and helium leak test. The irradiation test for the fuel elements were successfully completed at the HANARO research reactor.

• Journal of Welding and Joining
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• v.19 no.1
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• pp.88-94
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• 2001

DUPIC (Direct use of spent PWR fuel in CANDU reactors) nuclear fuel is a CANDU fuel fabricated remotely from spent PWR fuel materials in a hot cell. The soundness of the end closure welds of nuclear fuel elements is an important factor for the safety and performance of nuclear fuel. To evaluate the soundness of the end closure welds of DUPIC fuel element, a precise X-ray inspection system is developed using a micro-focus X-ray generator with an image intensifier and a real time camera system. The fuel elements made of Zircaloy-4 and stainless steel by an Nd:YAG laser welding and a TIG welding aye inspected by the developed inspection system. The soundness of the welds of the fuel elements was confirmed by the X-ray inspection process, and the irradiation test of DUPIC fuel elements has been successfully completed at the HANARO research reactor.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.484-485
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• 1987

The characteristics of leader development in rod -to- plane air gap (20cm gap length) under positive impulse potentials have been studied by means of 2-photomultiplier technique and image intensifier camera. It was shown that the streamers radiate relatively short wavelength light (${\sim}340nm$) while the leaders radiate a plenty of long wave length light ($400{\sim}800nm$). It was also known that the streamers propagate very fast with a velocity of $6{\times}l0^7cm/sec$ but the leaders have average velocity of $5{\times}10^6cm/sec$ and they proceed gradually fast by step-wise development.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.294-296
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• 1996

The process of detecting edge in an image is an important component of many Pattern Recognition and Computer Vision applications. In many practical cases, there exist blurred images due to defocussing, movement of an object and so on. In addition, local perturbation noise can be added to the images. We propose the edge detection technique in blurred and noisy image. For this, we use Fuzzy pyramid linking mothod to remove noise and enhance the edge in images. We develop contrast intensifier using the concept of Fuzzy sets as a postprocessing.

• The Korean Journal of Pain
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• v.7 no.1
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• pp.59-64
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• 1994

Splanchnic nerve block is effective in relief of upper abdominal cancer pain. But we often get confused at the unexpected complaints of pain accompanying a metastatic of referred origin in spite of the precise block under image intensifier. We could found aut a thermographic change from the diffuse hyperemission state of abdomen before the block to the localized state after the block. It may be helpful in differentiating objectively the accuracy of the block at the unexpected complaints of pain by using thermography before and after the block.

• The Korean Journal of Pain
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• v.7 no.1
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• pp.116-118
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• 1994

Neurolytic splanchnic nerve block is effective for treatment of intractable upper abdominal cancer in. The possibility of neurologic complication cannot be completely precluded. A 53 year-old female patient with hepatoma and lung metastasis was submitted for splanchnic nerve block with alcohol. Splanchnic nerve block was performed under radiologic control by image intensifier without any difficulty during procedure. One day after the block, she complained of numbness with sensory deficit in bilateral inguinal area. Neurologic examination revealed that asymmetrical anesthesia, hypoesthesia at $T_{12}-L_2$. She was discharged 70 days after the block with partial improvement. The possibility of alcohol spreading to the low theracic and upper lumbar somatic nerves cannot be excluded.