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Spill-over 억제를 위한 X-band 카세그레인 안테나 설계 연구
이우상,장원,이병무,양기주,이상흔,윤영중,Lee Woo-Sang,Jang Won,Lee Byoung-Moo,Yang Gi-Joo,Lee Sang-Heun,Yoon Young-Joong 한국전자파학회 2006 한국전자파학회논문지 Vol.17 No.9
본 논문에서는 초고출력용 X-band 카세그레인 반사판 안테나 시스템에서 반사판의 표면 형상을 변형시켜 spill-over가 효과적으로 감소하는 현상에 대하여 이론적인 고찰을 수행하였다. 이러한 구조는 이중의 쌍곡면 부 반사판을 적용함으로써 주 반사판의 크기를 확장하지 않고 급전 혼 안테나에서 방사된 전파 패턴의 확장각을 증가시켜 spill-over특성이 감소되도록 설계하였다. 결과적으로 본 논문에서 제안된 카세그레인 반사판 안테나가 기존의 설계 방법에 의한 반사판 안테나에 비해 약 9 %의 효율 향상과 10 dB의 부엽 레벨 감소가 구현됨을 이론적으로 확인하였다. In this paper, new structure of the Cassegrain reflector antenna whose spill-over is efficiently reduced by modified reflectors is proposed for high power. It can be achieved by designing the geometry of subreflector in Cassegrain system using two hyperbolic curves in order to be suitable a lager beamwidth of feeding pattern without broadening main reflector. Finally, radiation efficiency and side lobe level of the proposed Cassegrain reflector antenna can be improved respectively 9 %, 10 dB than conventional one.
교량 상시계측시스템을 이용한 실시간 안전성평가시스템 구축 방안
이우상,주봉철,박기태,Lee. Woo-Sang,Joo. Bong-Chul,Park. Ki-Tae 한국방재학회 2008 한국방재학회 학술발표대회논문집 Vol.2008 No.1
The research was carried out to suggest the bridge health monitoring systems that have been composed damage detection algorithm and a system for evaluation load carrying capacity of bridge by traffic loads for the purpose of safety management of bridge structure in efficient and economic.
유동법에 의한 용융 ZnCl<sub>2</sub> 및 FeCl<sub>2</sub>의 증기압 측정
이우상,김원용,정우광,Lee, Woo-Sang,Kim, Won-Yong,Jung, Woo-Gwang 한국재료학회 2010 한국재료학회지 Vol.20 No.3
Chloride-based fluxes such as NaCl-KCl are used in the refining of Al melt. The vapor pressure of the chloride is one of the fundamental pieces of information required for such processes, and is generally high at elevated temperatures. In order to measure the vapor pressure for chlorides, the apparatus for the transpiration method was assembled in the present study. The vapor pressure of $ZnCl_2$ and $FeCl_2$, which is related with the process of aluminum refining and the recovery of useful elements from iron and steel industry by-products, was also measured. In the measurement of vapor pressure by the transpiration method, the powder of $ZnCl_2$ or $FeCl_2$ in a alumina boat was loaded in the uniform zone of the furnace with a stream of Ar. The weight loss of $ZnCl_2$ and $FeCl_2$ after holding was measured by changing the flow rate of Ar gas (10 sccm -230 sccm), and the partial pressures of $ZnCl_2$ and $FeCl_2$ were calculated. The partial pressures within a certain range were found to be independent of the flow rate of Ar at different temperatures. The vapor pressures were measured in the temperature range of 758-901K for $ZnCl_2$ and 963-983K for $FeCl_2$. The measured results agreed well with those in the literature.