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Push-Push FET DRO에 부가된 유전체 공진기의 전력 증강 역할에 관한 분석
박승욱,김인석 한국전자파학회 2003 한국전자파학회논문지 Vol.14 No.11
본 논문에서는 Push-Push FET DRO회로의 게이트단에서 이용했던 동일한 유전체 공진기를 드레인단에 추가하면 출력이 증강되는 현상을 이론적으로 해석하였다. 본 해석은 두 개의 마이크로스트립 선로 사이에 위치한 유전체 공진기가 두개의 FET 출력 의 위상차를 고정시켜서 Push-Push FET DRO의 출력이 증가되는 것을 보인다. 이 영향을 Push-Push FET DRO 발진기 제작에서 발생할 수 있는 두 개의 FET 출력회로 사이의 임피던스 차이와 전력결합기의 전기적인 길이 오차를 수정하기 위해 사용할 수 있기 때문에 유전체 공진기가 부가된 Push-Push FET DRO는 발진기 제작에 유용한 구조가 될 것이다. In this paper, the output power improvement of Push-Push FET DRO by adding the identical DR at the drain port as one used in the gate port, has been theoretically investigated. The investigation shows that the DR located between two microstrip lines locks the phase difference of two FET's outputs at 180 degree and improves the output power of Push-Push FET DRO. Since this effect can be used for correcting the impedance difference between two FETs output circuits and the electrical length error of the power combiner at the output circuit of Push-Push DRO, which may occur when fabricate the oscillator, the oscillator with an additional DR can be useful structure for fabricating oscillator.
박승욱,홍진원,김미화,Park, Seung-Wook,Hong, Jin-Won,Kim, Mee-Hwa 한국벤처창업학회 2010 벤처창업연구 Vol.5 No.2
The National Research and Development(R&D) has put a greater emphasis on development of a market- and customer-oriented technology and its commercialization in the market. To promote commercialization of technologies invented through the national R&D, many governmental and public organizations have been offering various assistance programs. In spite of these assistance programs, the commercialization rate of the Korean national R&D outcomes is relatively lower than other advanced countries including the United States and European countries. Thus, this paper analyzed 24 R&D commercialization assistance programs which are provided by several institutions in the four different nations. As a result of analysis, we recommended the areas for improvement in the Korean R&D commercialization assistance programs. Also we suggested a framework driving an effective collaboration among the institutions assisting commercialization, the institutions funding and managing R&D, and the people performing R&D.
전산유체역학을 이용한 용접흄농도 간접적 예측가능성 연구
박승욱,김태형,서정윤,허영빈,임정호,강대웅,하현철,Piao, Cheng Xu,Kim, Tae Hyeung,Seo, Jeoung Yoon,He, Rong Bin,Lim, Jung Ho,Kang, Dae Woong,Ha, Hyun Chul 한국산업보건학회 2009 한국산업보건학회지 Vol.19 No.4
There are various methods for welding fume control. These methods can be divided into local exhaust system, general ventilation system and integrated control system. With the general ventilation system, we should have a good prediction tool for testing various appropriate control options. But, until now there are not many studies about how to predict the welding fume concentrations. Especially, the prediction of welding fume concentration is not a very easy task because welding fume is the particulate matters. In this study, we tried to measure $CO_2$ concentrations and welding fume concentrations in a small single room with a small ventilation opening. Using commercially available CFD (Computational Fluid Dynamics) software, we tried to predict $CO_2$ concentrations under the exactly same conditions. Then, we tried to compare the numerical $CO_2concentrations$ with the experimental results to know whether we could predict $CO_2$ concentrations. Then we tried to compare $CO_2$ concentrations with experimental welding fume concentrations to know whether we can use the numerical $CO_2concentrations$ to predict the welding fume concentration indirectly.
국가 R&D 사업의 계획단계 강화를 위한 분석 및 제언
박승욱,홍진원,김미화,Park, Seung-Wook,Hong, Jin-Won,Kim, Mee-Hwa 한국벤처창업학회 2010 벤처창업연구 Vol.5 No.3
In spite of increased R&D budget, the government has not produced outstanding and notable outcomes that have widespread effects on industries and economies. Lacking of solid planning for the R&D projects before they implement is one of the leading reasons. This study conducted case studies for the R&D projects implemented in Korea and other foreign countries, and made suggestion on how to improve the planning practices for the large-scale governmental R&D projects. The purpose of this study is to provide an implications on the policies about the nation-wide R&D planning system.