http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Seiya Watanabe (검색결과 3 건)
- 무료
- 기관 내 무료
- 유료
-
Seiya Ueno,Ryuichi Watanabe 한국항공우주학회 2008 한국항공우주학회 학술발표회 논문집 Vol.- No.-
This paper treats with the calculation procedure of reference trajectory to be applied to emergency guidance and control law for future reusable space transportation systems, such as spaceplane. The reusable transportation system is required to return to the landing area safely even if unexpected malfunction causes and the mission is aborted. Low computational load is necessary lor the emergency guidance law because reference trajectory must be calculated through an onboard computer within a short time. And also the reference trajectory is required to be followed by a spaceplane with low performance in maneuver. Thus it is desired that the reference trajectory is provided as a solution of minimum curvature problem, which is an optimal control problem. This paper proposes the calculation procedure of optimal control problem without iterative calculation. Homotopy method is applied to solve optimal control problems. Numerical results show that calculation of define integral provides three dimensional optimal trajectory.
-
Lubricating property of cyano-based ionic liquids against hard materials
Shouhei Kawada,Keisuke Sato,Seiya Watanabe,Shinya Sasaki 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.12
Ionic liquids are expected to be used as a new lubricants and lubricant additives because of their unique properties. However, cyanobased ionic liquids have exhibited poor lubricating property with steel/steel contacts. We evaluated the lubricating properties of cyanobased ionic liquids with steel/hard materials contacts. TiO 2 , Al 2 O 3 , and tetrahedral amorphous carbon (ta-C) DLC were used as hard materials. Six types of ionic liquids, as combination of two types of cations ([EMIM], [BMPL]) and three types of cyanide anions ([DCN], [TCC] and [TCB]), were selected. In sliding tests of steel/TiO 2 and steel/Al 2 O 3 lubricated with [EMIM][DCN], [BMPL][DCN], [EMIM][TCC], [BMPL][TCC] exhibited low friction coefficients of less than 0.1. In addition, steel/Al 2 O 3 and steel/ta-C DLC lubricated with [BMPL][TCB] exhibited very low friction coefficients less than 0.05. On the other hand, high friction coefficients were observed at steel/TiO 2 and steel/Al 2 O 3 contacts lubricated with [EMIM][TCB] and steel/ta-C DLC contact lubricated with [EMIM] cation group. Peeling of the ta-C DLC was observed when [EMIM] cation group was used. ToF-SIMS analysis indicated that the anion was adsorbed on the worn surfaces in the case of low frictional conditions. However, both ions were hardly observed in the case of high frictional conditions. It is considered that the ionic liquids underwent tribo-decomposition on the worn surfaces at low friction coefficient. To evaluate the degree of tribo-decomposition, Thermogravimetric analysis (TGA) was used. TGA results indicated that [EMIM][TCB], which exhibited high friction coefficient, had the most highest stability among all ionic liquids. Low stability ionic liquids, however, showed a tendency for low friction coefficient. These results suggest that lubricating properties are related to the stability of ionic liquids.
-
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
