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액체산소/케로신 가스발생기 사이클 액체로켓엔진 터빈 노즐목 면적 변화 추정 방법
남창호(Chang-Ho Nam),문윤완(Yoonwan Moon),박순영(Soon Young Park),김진한(Jinhan Kim) 한국추진공학회 2019 한국추진공학회지 Vol.23 No.5
Carbon deposition on the turbine nozzle throat of a LO<SUB>x</SUB>/kerosene gas generator cycle(open cycle) engine causes performance reduction of the engine. Estimation methods for a turbine nozzle throat area are proposed. The discharge coefficient of the turbine nozzle was estimated with the turbine gas properties such as gas constant, specific heat ratio, and temperatures. The pressure ratio and temperature ratio of the turbine nozzle throat, was utilized to estimate the discharge coefficient also. Estimated discharge coefficient of turbine nozzle throat of KSLV-II 1st stage engine shows the carbon deposition effects on the turbine nozzle throat of a LOx/kerosene open cycle engine.
액체산소/케로신 가스발생기 사이클 액체로켓엔진 터빈 노즐목 면적 변화 추정 방법
남창호(Chang-Ho Nam),문윤완(Yoonwan Moon),박순영(Soon Young Park),김진한(Jinhan Kim) 한국추진공학회 2019 한국추진공학회 학술대회논문집 Vol.2019 No.5
액체산소/케로신 가스발생기 사이클 엔진의 터빈 노즐목 수트(soot) 침착 특성을 파악하기 위한 변수를 정의하고 한국형발사체 1단 엔진 시험결과에 적용하였다. 터빈 가스의 물성치를 이용한 노즐목의 분출 계수 정의를 하는 방법이 있고 터빈 노즐목 전단과 터빈 배기 노즐목 전단의 압력비와 온도비를 이용하여 분출계수를 정의할 수 있다. 한국형발사체 1단 엔진 시험 결과를 분석한 결과 터빈 노즐목의 분출계수(discharge coefficient)는 시간에 따라 감소하며 동일 엔진에 대한 누적 연소시간에 대해서도 감소하는 경향을 보인다. 누적 시험 초기에는 터빈 노즐목 감소가 그 다음 시험과 연계되지만 일정 시간 이후에는 일정 범위에서 등락을 거듭하는 듯한 특성을 보인다. Carbon deposition on the turbine nozzle throat of a LOx/kerosene gas generator cycle(open cycle) engine causes performance reduction of the engine. Estimation methods for a turbine nozzle throat area are proposed. The discharge coefficient of the turbine nozzle can be formulated theoretically with the turbine gas properties such as gas constant, specific heat ratio, and temperatures. The pressure ratio and temperature ratio of the turbine nozzle throat, can be utilized to estimate the discharge coefficient also. Estimated discharge coefficient of turbine nozzle throat of KSLV-II 1<SUP>st</SUP> stage engine shows the carbon deposition effects on the turbine nozzle throat of a LOx/kerosene open cycle engine.
Mobile IPv6 환경에서 신뢰성 있는 TCP 프로토콜의 성능향상에 관한 연구
姜昊錫,金南昌,沈永喆 弘益大學校 科學技術硏究所 2003 科學技術硏究論文集 Vol.14 No.-
There are three methods for improving performance of TCP Protocol in the Mobile IPv6 Environment. Those methods are link layer protocol method, end-to-end protocol method and split-connection method. It's a link layer protocol method among these to be applied without any changes of wired network environment. Snoop module is one of link layer protocol methods for improving performance of TCP Protocol. We apply snoop module to Mobile IPv6 and improve Mobile IPv6 with snoop module by changing some feature of Mobile IPv6 which reduces its performance. Based on these improvement of Mobile IPv6, We simulate it by ns2 and mobiwan comparing original Mobile IPv6 and our Mobile IPv6 with snoop module. Simulation of ours is better than original.
울/텐셀 혼방직물의 표면가공처리에 따른 감성에 대한 연구
홍철재,남창일,김정규 한국섬유공학회 2000 한국섬유공학회지 Vol.37 No.8
The trend of fashion, which was affected by historical event and culture, plays an important role in determining textile fabrication. The fabrication has been made not only by introducing the newly developed fiber but also by modifying the existing textile materials to impart sensibility to them. In this research, focusing on the latter case, we carried out the fabrication of women clothes specially for fall and winter. A survey on fashion trend through 1990s was made to forecast the fashion trend of 2000 years. Based on the forecasted trend, the fabrication in 2000 was expected to mostly use angora wool that possesses high luster, highly soft touch and highly wet look. However, angora wool is very expensive and thus, it is needed to introduce other fibers the properties of which are almost similar to those of angora. In this research, tencel fiber was introduced to substitute for angora wool. Tencel fabrics prepared were finished chemically with enzyme treatment and phsically with surface raising in a bid to impart to them sensitivity peculiar to angora. In order to characterize the imparted sensitivity, physical properties measured are compressibility, bending, tensile strain, surface properties, and etc. Result showed that the enzyme treated tencel fabric was much closer to the angora fabric than the enzyme untreated tencel fabric.
시간이력 해석법을 사용한 교량의 지반-구조물 상호작용해석
김운학,유영화,김남창 안성산업대학교 2002 論文集 Vol.33 No.-
A response analysis of bridge subjected to seismic forces is performed by applying seismic input motion at the base defined in Free Field to the footing, under the usual assumptions that the base is rigid body and the superstructure is rigidly connected to the base. Seismic design of bridge is required to consider the facts that the base has flexibility and this property may give an effect on the seismic response of superstructure. In this paper, the effects specified above have been considered in soilstructure interaction(SSI) time history analysis by SAP2000, where instead of conventional seismic design concept which uses a site coefficient and a assumption of rigid footing, substructure method has been incorporated into the analysis after evaluating the equivalent spring constant representing those properties. An artificial earthquake simulated from the design spectrum specified in Guideline for Highway Bridges was used throughout the 3-D analysis. Using equivalent spring constant representing the base footing makes it possible to predict more realistic behavior, which was not found in conventional analysis.
강호석(Hoseok Kang),김남창(Namchang Kim),심영철(Youngchul Shim),이진석(Jinseok Lee),장인숙(Insook Jang) 한국정보과학회 2003 한국정보과학회 학술발표논문집 Vol.30 No.2Ⅰ
표준으로 정의된 IT제품의 보안성 평가 방안들은 CC나 ITSEC, TCSEC과 같이 많이 나와있다. 그러나 이러한 표준은 너무 추상적이고 소프트웨어의 각 단계에 따른 보안성을 측정하는데 불충분한다. 또 SSE-CMM같은 프로세스를 평가하는 방법의 경우 역시 너무 추상적이고 포괄적인 연만을 설명하였고 프로세스 자체에 대한 평가에 중점을 두었을 뿐 각 단계의 보안강도를 평가하는데는 부족하다. 이 논문에서는 이러한 단점을 보안하고자 각 공정단계에서, 특히 제품을 계획하는 단계인 요구분석단계와 디자인 단계에서 그래프 모델링과 모듈 다이어그램 통한 검증방법을 제시하였다. 여기서는 보안 운영체계라고 특정 제품을 명시하였지만 실제로 다양한 IT제품에 적용될 수 있다.
한국형발사체 액체로켓엔진 개발 현황 - 7톤급 및 75톤급 엔진
문윤완(Yoonwan Moon),남창호(Chang-Ho Nam),박순영(Soon-Young Park),김진한(Jinhan Kim),고정환(Jeonghwan Ko) 한국추진공학회 2019 한국추진공학회 학술대회논문집 Vol.2019 No.5
한국형발사체는 1, 2단에 75톤급 액체로켓엔진의 지상용과 고공용 모델이 각각 장착되고 3단에는 7톤급 엔진이 장착된다. 2018년 TLV 발사 성공에 따라 75톤급 엔진의 지상용 모델은 강건성이 입증되었고, 연소기의 확대 노즐을 제외한 동일한 구성품으로 이뤄진 2단용 엔진은 2019년 연말까지 엔진 인증 시험을 수행할 예정이다. 7톤급의 3단용 엔진은 각 구성품의 특성을 파악하기 위해 지상 시험용 모델을 주로 제작하고 시험하였고 결과를 바탕으로 설계 수정을 진행하여 2019년부터 2020년 상반기까지 실제 비행용 모델과 동일한 고공용 엔진의 검증 시험과 엔진 인증 시험을 수행할 예정이다. The ground and altitude models of 75 tonf class LRE are installed in the first stage and second stage of KSLV-II. Also in the third stage of KSLV-II 7 tonf class LRE is assembled. The robustness of 75 tonf LRE was proved in accordance with successful launching of TLV in 2018. The LRE of the second stage which is commonly used components of 1<SUP>st</SUP> stage LRE will be qualified by test until the end of 2019. Until now, the ground model of 7 tonf LRE was mainly tested to investigate the characteristics of newly developed small engine. Through the analysis of 7 tonf LRE test results the modified engine design of 7 tonf LRE is applied to the altitude model which is idnetical with a flight model. Then the altitude model of 7 tonf LRE will be verified and qualified from 2019 to the first half of 2020.