• 제목/요약/키워드: 김대현

검색결과 798건 처리시간 0.023초

고주파 진동 측정을 위한 FBG 센서 시스템 개발 및 복합재 시편의 고유진동수 측정 (Development of FBG sensor System for Measuring the High Frequent Vibration of Structures and the Natural Frequency of Composites)

  • 김대현;구본용;김천곤;홍창선;이인
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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    • pp.159-162
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    • 2002
  • We introduce a simple optically passive detection scheme for Bragg grating sensors. This detection scheme is based on two cavity lengths in Fabry-Perot read-out interferometers to produce two quadrature phase shifted signals from the Bragg grating sensor. The passive detection technique is demonstrated by the use of Bragg grating sensors in measuring the dynamic vibrations of the composites.

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모울드 금형의 무인가공을 위한 자동공정계획 몇 지능형 NC 데이터 생성 (Automated process plan and an intelligent NC data generation for unmaned machining of mould die)

  • 유우식;김대현
    • 산업경영시스템학회지
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    • 제19권40호
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    • pp.143-155
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    • 1996
  • Presented in this paper are a CAPP(Computer Automated Process Planning) scheme and a generating method of intelligent NC data for unmaned machining of mold die. Mold die surfaces usually have free-formed geometry of complex shapes. So it is easy to overcut the die surface and to overload the cutting tools. It takes tens of hours to prepare process plans and to generate NC data for each processes. Therefore a classification of unit machining operation(UMO) for mold die manufacture, a backward recursive capp algorithm and a generating method of intelligent NC data are presented in this paper in order to provide a unmaned machining architecture of mold die.

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루프형 열사이폰을 이용한 열전발전 시스템 (Thermoelectric Power Generation System with Loop Thermosyphon)

  • 김선국;이석호;원병철;김대현;이충구
    • 대한기계학회논문집B
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    • 제33권9호
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    • pp.718-721
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    • 2009
  • A new progressive advanced approach (Loop thermosyphon Thermoelectric Power generation System) is suggested to optimize heat recovery ability from vehicle exhaust gas. As an initial look at device feasibility, the present new TE system adopted the loop thermosyphon as a cooling heat exchanger. The TE system with loop thermosyphon was investigated in terms of working fluids, instability of system, amount of working fluid, and so on. Basically, the present experimental works have been focused on finding the optimum working condition of the system to improve thermoelectric power output and to obtain stable power generation to operate hybrid vehicles. The present experimental results with the loop thermosyphon TE module shows possibilities as an improved TE system for future thermoelectric hybrid vehicles.

하이퍼스펙트럴 위성영상을 이8한 연안지역의 수심산정 (Estimation of Water Depth in Coastal Area Using Hyperspectral Satellite Imagery)

  • 이종출;김대현;이영도;유영화
    • 한국측량학회:학술대회논문집
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    • 한국측량학회 2006년도 춘계학술발표회 논문집
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    • pp.165-169
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    • 2006
  • Purpose of this research is estimation of water depth by hyperspectral remote sensing in area that access of ship is difficult This research used EO-1 Hyperion satellite imagery. Atmospheric and geometric correction is executed. Compress of band used MNF transforms. Diffuse Attenuation Coefficient of target area is decided in imagery for water depth estimation. Determination of Emdmember in pixel is using Linear Spectral Unmixing techniques. Water depth estimated using this result.

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파두전탕액(巴豆煎湯液)이 흰쥐의 혈액(血液)에 미치는 실험적(實驗的) 연구(硏究) (Experimental study of Triglii semen(巴豆) on the blood in Rats)

  • 김대현;정찬길;김광호;소경순
    • 대한약침학회지
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    • 제8권3호
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    • pp.21-29
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    • 2005
  • In order to Experimental study effects of ${\ulcorner}Triglii\;Semen{\lrcorner}$ on the blood in Rats, we have made rats by administering Animal control chamber for two weeks, then have administered. The results is were summerized as follows: 1. The total cholesterol, triglyceride and Hct, Hb by generally rats oral ingestion by Triglii semen of the sample group were decreased as compared with those of the control group. 2. GOT, GPT by generally rats oral ingestion were increased as compared those of control group. According to the above results, Triglii Semen showed inhibition on decrease of serum total cholesterol and Hb, Hct, WBC, RBC contents as well as inhibition on increase of GOT, GPT.

750kw급 직접 구동형 풍력 발전기의 제어 시스템 개발 (Control System Development of 750kW Direct Drive Wind Turbine Generator)

  • 김대현;황진수;이승훈;장성태;류지윤
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2005년도 춘계학술대회
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    • pp.55-58
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    • 2005
  • 풍력발전기에 있어서 보호 및 제어 시스템은 그 효율, 성능, 안전 및 수명까지도 영향을 미칠 수 있는 중요한 구성요소이다 따라서 제어 시스템은 풍력발전기의 최대 효율 및 가동률을 확보하여야 하며 풍력발전기에 문제가 발생할 경우 즉시 가동을 정지할 수 있도록 안전성을 확보할 수 있도록 설계되어야 한다. 본 연구에서는 "750kw급 Gearless형 풍력발전시스템 개발" 과제의 일환으로 수행되었던 풍력발전기용 제어시스템의 설계 및 제작 과정과 상용제품으로서의 본 제어 시스템을 소개하고자 한다.

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마찰감쇠기-가새 시스템의 등가선형화 기법에 관한 연구 (Equivalent linearization of a Friction Damper and Brace System)

  • 민경원;박지훈;김대현;김형섭;문병욱;강상훈
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2005년도 춘계학술대회논문집
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    • pp.750-753
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    • 2005
  • An equivalent linearization technique based on Rayleigh peak distribution for friction damper and brace system (FDBS) under stochastic excitation is proposed. For verification, shaking table test of a small scale 3-story building model with the FDBS is conducted for various slip moment levels. Using experimental result, equivalent linearization of the FDBS is conducted based on Rayleigh peak distribution, which is compared with measured peak distribution. For comparative study, model updating technique is applied based on identified modal properties. Finally, complex modal analysis and time history analysis for the obtained equivalent linear systems are conducted and compared with experimental result

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750kW Gearless형 풍력발전시스템 국산화 개발

  • 류지윤;김두훈;박진일;황진수;변철진;김대현;방조혁;장성태;정진화;전중환;김동언;오종석
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2005년도 제17회 워크샵 및 추계학술대회
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    • pp.229-243
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    • 2005
  • 본 연구는 2001년 12월부터 2004년 12월까지 정부지원으로 유니슨(주)가 개발을 주관하고 포항공과대학교 및 국내 관련 기업이 참여한 콘소시엄에서 개발한 750kW Gearless형 풍력발전시스템의 국산화 개발에 관한 연구결과로서 풍력발전 시스템의 하중평가, 구성요소품의 설계 결과와 블레이드, 발전기 및 전력변환장치 등 개발요소품의 성능시험결과와 국제 설계인증 추진 및 시제품 제작에 대한 내용을 포함하고 있다.

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Bacteria를 이용한 연약한 흙의 고결화 가능성 (Possibility of cementation of soft soil using Bacteria)

  • 김대현;김호철;박경호
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2010년도 추계 학술발표회
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    • pp.379-391
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    • 2010
  • In order to understand the mechanism of cementation of soft soils treated with bacteria, three types of specimens(untreated, normal bacteria concentration treated, and high bacteria concentration treated) were made. Scanning Electron Microscope(SEM), EDX and X-ray diffraction(XRD) analyses were performed on the soft silt and loose sand specimens. Compared with the untreated specimen, a clearer cementation between particles was observed in the high bacteria concentration treated specimen. Based on the scanning electron microscope(SEM) EDX analyses, more calcium carbonate was observed in the specimen treated with high bacteria concentration than other specimens. On the basis of the preliminary results, it appears that microbial cementation can occur in the soft soil. Further study on the cementation of soils using bacteria is necessary to validate this result.

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원발성 식도 악성 흑색종 -1례 보고- (Primary Malignant Melanoma of the Esopahgus -A Case Report-)

  • 이응배;김대현;박태인
    • Journal of Chest Surgery
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    • 제35권4호
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    • pp.322-324
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    • 2002
  • 2개월동안의 연하곤란으로 입원한 56세남자 환자로 술전 원발성 식도 악성 흑색 종으로 판명되었으며 수술을 시행한 증례를 보고한다. 술전 식도내시경상 폴립(용종)양 종양이었으며 우측개흉술을 통해 식도 전절제술 및 위를 사용한 식도 재건술을 시행하였다. 종양은 술후 시행한 조직검사 및 면역조직화학검사상 원발성 식도 악성 흑색종이었다. 병리학적 병기는 IIa였고, 술후 다른 보조요법은 받지 않았다. 환자는 간전이에 의해 술후 8개월에 사망하였다.