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오스템퍼링한 구상흑연주철의 마모특성에 미치는 기지조직의 영향에 관한 연구
김윤복,김창규,최창옥 ( Yun Bog Kim,Chang Gyu Kim,Chang Ock Choi ) 한국주조공학회 1990 한국주조공학회지 Vol.10 No.3
N/A This study hay been carried out to investigate into the rolling wear characteristics of austempered ductile iron under unlubricated dry rolling condition by Amsler type test with 9.09% sliding ratio. Wear amount is increased with increasing of ferrite and retained austenite and it has been found that the amount of rolling wear is decreased when the hardness of matrix are higher. The rolling life up to generation of abnormal condition is conspicusly increased and amount of rolling wear is increased asrolling revolutionis increased and wear of austempered ductile ironunder dry rolling condition. Matrix has been obtained to upper bainite, low bainite at heat treatment, obtained to bull`s eye structure at as cast. It has been found that the amount of rolling wear is decreased when the tensile strength of the casting are increased and then the rolling life up to generation of abnormal wear in conspicuously increased and amount of wear was intend to graphite content.
김윤복(Yoon -Bok Kim) 산업기술교육훈련학회 2010 산업기술연구논문지 (JITR) Vol.15 No.4
This paper is purposed to analyze current and voltage waveforms and thermal characteristic for poor contact of electrical connector(breaker load connector). In this paper, current and voltage waveforms by loads(lamp, drill and electric heater) and thermal data by poor contact are analyzed distinguishing data for normal state. The current and voltage waveforms can not easily distinguish between poor contact and normal state. Thermal characteristic without vibration is generated thermal energy different then normal state and after 20 minute, breaker load connector is generated high thermal energy of over 210℃. Therefore, the poor contact data are referred and applied by poor contact basic data of current and voltage waveforms and thermal data.
김윤복(Yoon-Bok Kim),송성호(Sung-Ho Song) 산업기술교육훈련학회 2009 산업기술연구논문지 (JITR) Vol.14 No.2
The paper considers the electrical shock risk of the human body due to underwater leakage current in electric field. The characteristics of electric shock in fresh water due to the leakage of submerged electric facility in the bathtub in public baths were conducted. The exposed live electrode is modeled as a point source of electric current source. It is assumed that divergent monopole field exists in the vicinity of the current source, regardless of the presence of return electrode and insulating boundary. Diesen and Mole equations are measured according to the distance from leakage source. The results show that the increased shock risk and safe distance are estimated by the bathtub of limited width and the voltage calculated on the basis of a divergent monopole field concept is compared with the measured value.
초등학교 저학년과 미취학 아동을 위한 로봇 활용 교수ㆍ학습 프로그램 개발에 관한 연구
김동연(Kim, Dong Yeon),김윤복(Kim, Yoon Bok),박정호(Park, Jung Ho),김진수(Kim, Jin Soo) 한국실과교육학회 2007 한국실과교육학회지 Vol.20 No.2
This research is thing about teaching·learning program development which using robot to elementary school lower classes (1, 2, 3 years) and preschool(6, 7 age) child(K-3rd graders). That is, robot specialist, machine specialist, electricity electron specialist, design specialist, education and environment specialists develop(2004-2006) research about 3 years. Main contents of this research are as follows. First, study straight and rear guard teaching·learning program that using robot. Second, that using robot fixing from right left teaching·learning program study. Third, study draw a diagram teaching·learning program that using robot. Fourth, study application teaching·learning program that using robot. Fifth, study English word teaching·learning program that using robot. Sixth, study Chinese character teaching·learning program that using robot. Together, consider enough affective domain, cognitive domain, psychomotor domain that is elementary school lower classes and each domain special quality of preschool children in this research, study and developed teaching·learning program which utilize robot and robot. Therefore, investigators expect that this research contributes greatly in elementary school lower classes students robot education activation.
김윤호(Yoon-Ho Kim),김윤복(Yun-Bok Kim),류홍우(Hong-Woo Ryu),김찬기(Chan-Ki Kim) 전력전자학회 1997 전력전자학술대회 논문집 Vol.1997 No.-
MCT는 MOS-게이트형 사이리스터로써 MOS-게이트형 턴-온 및 턴-오프 특성과 낮은 도통전압을 나타내는 소자이다. 그러나 SOA(Safe Operation Area)가 상대적으로 작기 때문에 스너버 회로를 필요로 한다. 본 논문에서는 간단한 MCT PSPICE 모델을 사용하여 스위칭 특성과 RCD 스너버의 특성을 분석하였고 스너버 회로 설계방식을 제안하였다.
태양광 발전 PCS 구성부품에 대한 열적특성 및 고장모드영향분석
김두현 ( Doo-hyun Kim ),김성철 ( Sung-chul Kim ),김윤복 ( Yoon-bok Kim ) 한국안전학회(구 한국산업안전학회) 2018 한국안전학회지 Vol.33 No.4
This paper is analyzed for the thermal characteristics(1 year) of the 6 components(DC breaker, DC filter(including capacitor and discharge resistance), IGBT(Insulated gate bipolar mode transistor), AC filter, AC breaker, etc.) of a photovoltaic power generation-based PCS(Power conditioning system) below 20 ㎾. Among the modules, the discharge resistance included in the DC filter indicated the highest heat at 125℃, and such heat resulting from the discharge resistance had an influence on the IGBT installed on the rear side the board. Therefore, risk priority through risk priority number(RPN) of FMEA(Failure modes and effects analysis) sheet is conducted for classification into top 10 %. According to thermal characteristics and FMEA, it is necessary to pay attention to not only the in-house defects found in the IGBT, but also the conductive heat caused by the discharge resistance. Since it is possible that animal, dust and others can be accumulated within the PCS, it is possible that the heat resulting from the discharge resistance may cause fire. Accordingly, there are two options that can be used: installing a heat sink while designing the discharge resistance, and designing the discharge resistance in a structure capable of avoiding heat conduction through setting a separation distance between discharge resistance and IGBT. This data can be used as the data for conducting a comparative analysis of abnormal signals in the process of developing a safety device for solar electricity-based photovoltaic power generation systems, as the data for examining the fire accidents caused by each module, and as the field data for setting component management priorities.
소프트 스위칭 보조 스위치를 가지는 ZVT-PWM 부스트 컨버터
김윤호(Yoon Ho Kim),김윤복(Yun Bok Kim),정재웅(Jai Woong Jeong) 전력전자학회 1998 전력전자학술대회 논문집 Vol.- No.-
This paper presents a soft-switching average current control PWM high power factor boost converter. Conventional boost ZVT-PWM converter has a disadvantage of hard-switching for auxiliary switch at turn-off A soft switched auxiliary switch is proposed to achieve a !ugh performance ZVT - PWM boost rectifier. The simulation and experimental results show that soft switching operation can be maintained for wide line and load range, which in turn improves the converter performance in terms of efficiency, switching noise and circuit reliability.<br/> <br/>