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30 W COB LED광원의 효율 개선을 위한 방열설계에 관한 연구
서범식,이기정,조영식,박대희,Seo, BumSik,Lee, KiJoung,Cho, Young Seek,Park, Dae-Hee 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.2
In this paper, thermal analysis of heatsink for 30 W class Chip-on-Board (COB) LED light source is performed by using SolidWorks Flow Simulation package. In order to increase the convection heat transfer, number of fin and shape of the heatsink is optimized. Furthermore, a copper spread is applied between the COB LED light source and the heatsink to mitigate the heat concentration on the heatsink. With the copper spread, the junction temperature between the COB LED light source and the heatsink is $50.9^{\circ}C$, which is $5.4^{\circ}C$ lower than the heatsink without the copper spread. Due to the improvement of the junction temperature, the light output is improved by 5.8% when the LED light source is stabilized. The temperature difference between the simulation and measured result of the heatsink with the copper spread is within $2^{\circ}C$, which verifies the validity of the thermal design method using a simulation package.
서범식(Beom-Sik Seo) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.7
블렌디드러닝(e러닝과 집합교육의 혼합교육)의 개념과 모델, 장점, 동향, 사례를 살펴보고, 전력사업 교육에 적용가능한 내용을 접목시켜 활성화하는 방안을 모색하고자 한다.
이기정,서범식,양종석,성백룡,박대희,Lee, Ki-Joung,Seo, Bum-Sik,Yang, Jong-Seok,Seong, Baeg-Yong,Park, Dae-Hee 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.1
In this paper, semiconducting shield specimens for a DC cable os fabricated and characterized by measurement of volume resistance, tensile strength, and the coefficient of expansion to show the electrical and mechanical characteristics of the semiconducting shield. Due to the PTC phenomenon, the volume resistance at $25^{\circ}C$ increases rapidly in comparison to the volume resistance at $90^{\circ}C$. Since the compounding ration of carbon black is low, the tensile strength and density become lower and the coefficient of expansion is increased. As the general specification of the tensile strength and density is $0.8kgf/mm^2$ and 150%, respectively, the fabricated specimen in this paper has excellent mechanical characteristic.
이기정,서범식,양종석,성백룡,박대희,Lee, Ki-Joung,Seo, Bum-Sik,Yang, Jong-Seok,Seong, Baeg-Yong,Park, Dae-Hee 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.2
In this paper, semiconducting shield specimens for a DC cable is fabricated and characterized by measurement of volume resistance, tensile strength, and the coefficient of expansion to show the electrical and mechanical characteristics of the semiconducting shield. Due to the PTC phenomenon, the volume resistance at $25^{\circ}C$ increases rapidly in comparison to the volume resistance at $90^{\circ}C$. Since the compounding ratio of carbon black is low, the tensile strength and density become lower and the coefficient of expansion is increased. As the general specification of the tensile strength and density is $0.8kgf/mm^2$ and 150%, respectively, the fabricated specimen in this paper has excellent mechanical characteristic.