• Annals of Clinical Neurophysiology
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• v.4 no.1
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• pp.78-80
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• 2002

A 32-year-old man who had worked at aluminum processing plant for 4 months visited us. He complained of numbness and paresthesia of both foot and hands and weakness of all extremities. Electrophysiologic study showed motorsensory polyneuropathy of diffuse axonal type with focal conduction block. And we discovered higher concentration of n-Hexane in his workplace. On sural nerve biopsy, bubbly enlarged nerve fibers in light microscope and thick myelin sheath and axonal degeneration on electron microscope were found. We diagnosed it as n-Hexane induced neuropathy.

• Macromolecular Research
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• v.14 no.6
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• pp.610-616
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• 2006

An azoinitiator linked to an epoxy oligomer, which could easily diffuse into the organoclay gallery and swell it, was used as an initiator to enhance the delamination of an organoclay, Cloisite 25A, in a matrix of styrenic polymers, poly(styrene-co-acrylonitrile) and polystyrene, during the preparation of a nanocomposite via an in-situ polymerization method. X-ray diffraction results and transmission electron microscopic observation of the morphology showed that the epoxy segment enhanced not only the delamination but also the extrication of ammonium cations from the organoclay gallery into the polymer matrix. The latter phenomenon induced the structural change of the alkyl group of ammonium cations in the gallery from a bilayer to monolayer structure, and also decreased the glass-rubber transition temperature as measured by a differential scanning calorimeter and dynamic mechanical analyzer.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.1
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• pp.27-34
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• 2010

To dissipate the heat generated from the switching devices in the inverter system of HEV, the water cooling structure is proposed. The bolt type cooling structure has a problem such as water leakage for high pressure of water, therefore the proposed cooling structure applied pipe structure in the heat sink. The heat dissipation characteristics for various structures of water channel and distance between heat source and water channel was analyzed through the simulation. heat dissipation effect for two types of water cooling structures was investigated. Based on the simulation results, two types of water cooling system for 30kW inverter system of HEV were manufactured and the heat dissipation effect was verified.

• Proceedings of the KOSOMBE Conference
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• v.1991 no.11
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• pp.142-144
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• 1991

In this study, we have developed 64 channel computerized cardiac mapping system using micro-computer for basic research of electrophysiology and electrical propagation in cardiac arrhythmias. The significant problems of this study are the simultaneous acquisition of large amount data at 64 sites, the need of accurate and rapid analysis, and the effective display of the analyzed data. To solve these problems, we made 64 channel signal pre-processing board in order to amplify and filter the raw signals. And the software for cardiac isochronous mapping which were presented immediately via computer-generated graphics has been developed. This system is expected to enable us to study pathophysiology of cardiac arrhythmia and to improve the results of diagnosis and surgical treatment for cardiac arrhythmia.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.8
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• pp.84-91
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• 2005

An experimental investigation has been carried out to examine heat-transfer characteristics of an axisymmetric, under-expanded, sonic jet impinging on a flat plate and the local measurement of surface pressures and heat transfer coefficients on a plate have been achieved together with a visualization test of shock structure in a jet. Heat transfer coefficients on a plate have been found to be changed significantly depending on the under-expansion ratio as much as the nozzle-to-plate distance. These phenomena could be explained by the wall pressure measurement and the shock visualization.

• Textile Coloration and Finishing
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• v.26 no.2
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• pp.106-113
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• 2014

Work-related falls are a major problem in the construction and roofing industries. To avoid serious injury to the worker caused by high decelerations or forces, different systems to absorb the energy of a fall are implemented in personal protective equipment. In this study, shock energy absorber lanyard protection tube was prepared using high tenacity PET fiber, P-aramid fiber, and UHMWPE fiber, respectively. Dynamic load test and static load test, bursting strength test based on the Korea fall protection equipment standard(Korea Occupational Safety & Health Agency standard 2013-13) or conformity European safety test(CE : EN355) were conducted. Especially maximum arrest force by dynamic load test of energy absorber showed below 6,000N.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.1053-1059
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• 2009

In this study, slope hazards mitigation methods for a natural terrain are systematically classified to survey the mitigation methods and develop a data base system. Also, field survey sheets which can be recorded the features of mitigation methods installed in the natural slope are developed. The slope hazards mitigation methods in the natural slope are classified as hillside part method and valley part method. The slope part sheet and the valley part sheet are also drawn up for field survey. As the result of the filed survey of mitigation methods about 50 points in Muju and Jangsu area, grass painting and slope covering methods are dominant in case of slopes part. In case of valley part, slit dam, concrete check dam and slope foot barrier are applied simultaneously.

• Korean Journal of Ichthyology
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• v.26 no.4
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• pp.336-339
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• 2014

The spadenose shark, Scoliodon laticaudus, belongs to the family carcharhinidae was described as the first record from Korea based on a single specimen collected from the South Sea of Korea. The species is characterized by having a greatly depressed and trowel-shaped head, a depressed and long snout, triangular pectoral fins, and posterior tip of the first dorsal fin reaching the middle of pelvic fin. We propose a new Korean names of the genus Scoliodon and the species S. laticaudus as "Nab-jag-ju-dung-i-sang-eo sog" and "Nab-jag-ju-dung-i-sang-eo", respectively.

• Tribology and Lubricants
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• v.27 no.6
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• pp.326-331
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• 2011

The purpose of this paper is to analyze and discuss the effects of surface roughness by comparing the elastohydrodynamic lubrication(EHL) analysis of smooth surface and rough surface as the ball bearing. In order to do this, The average flow model is adapted for the interaction of the flow rheology of lubricant and surface roughness. The average Reynolds equation and the related flow factor which describes the coupled effects of surface roughness and flow rheology, the viscosity-pressure and density-pressure relations equations, the elastic deformation equation, and the force balance equation are solved simultaneously. The results show that effects of surface roughness on the film thickness and pressre distribution should be considered especially in EHL contact problems.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.343-344
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• 2010

화석연료의 고갈로 인하여 친환경 자동차에 대한 연구와 상용화가 급속도로 진행되면서 점점 대형 차종으로 그 범위가 넓어지고 있다. 대형 차종에 적용되는 전기동력 시스템의 MCU(Motor Control Unit), GCU(Generator Control Unit), DC/DC 컨버터 등과 같은 전장품도 그 용량이 커지면서 상용화를 위해 효율적인 측면도 많이 부각되지만 스위칭 소자, 변압기, 초크, 다이오드 등에서 동작으로 인해 열이 발생하고 제품의 구조상 밀폐된 공간에 장착이 되기 때문에 발열로 인한 동작의 신뢰성과 제품의 내구성에 큰 영향을 미치게 된다. 그중 가장 발열이 심한 IGBT(Insulated Gate Bipolar Transistor) 등과 같은 스위칭 소자에서 발생하는 열을 효과적으로 냉각시키기 위해 수냉구조가 필수적이며 동일한 조건의 수압, 유량에 보다 높은 방열특성을 가지기 위해 냉각구조에 대한 해석이 제품을 개발 전에 선행되어야 한다. 본 논문에서는 유로의 냉각핀 형상과 유로 구조에 따라 방열특성이 어떠한 차이가 있는지 시뮬레이션 프로그램을 통하여 비교하고, 모사발열체를 이용한 방열부의 냉각 성능 시험과 다이나모 환경의 최대 출력 시험을 통하여 방열 특성을 확인하였다.