中国科学院机构知识库网格系统: 检索

浏览/检索结果: 共4条，第1-4条

帮助

条数/页：排序方式：
	Structural design of primary mirror subassembly for space telescope (EI CONFERENCE) 会议论文 OAI收割 2nd International Conference on Mechatronics and Applied Mechanics, ICMAM 2012, December 8, 2012 - December 9, 2012, Taiwan 作者: Xu H. 收藏 \| 浏览/下载：66/0 \| 提交时间：2013/03/25 In order to design a large aperture primary mirror with the diameter of 1150 mm the parameters impacting on gravity deformation of the mirror were analyzed and discussed in detail including material selection diameter-thickness ratio the number of the support points location selection and lightweight structure etc. A novel space mirror structure system was put forward and its back was opened and supported by six points on back. The dynamic and static and thermal characteristics were analyzed based on the finite element method. Analysis results showed the surface figure accuracy reached to RMS 14.5nm under the action of gravity load along the optical axis direction and the first-order natural frequency was 214Hz which met to the designed indexes requirements. (2013) Trans Tech Publications Switzerland.
	Tracking error modeling of the theodolite based on GRNN method (EI CONFERENCE) 会议论文 OAI收割 2nd International Conference on Frontiers of Manufacturing and Design Science, ICFMD 2011, December 11, 2011 - December 13, 2011, Taichung, Taiwan 作者: Li M. 收藏 \| 浏览/下载：28/0 \| 提交时间：2013/03/25 To meet the requirement of high tracking accuracy as well as develop more reasonable evaluation method in this paper the General Regression Neural Network (GRNN) has been applied to build the tracking error model of the theodolite. First we analyze the nonlinear factors in the theodolite. Second we discuss the principle of GRNN including its structure the function as well as its priors. Third we build the tracking error model based on GRNN and verify the model through the different parameters. The result indicated that the network model based on GRNN has high accuracy and good generalization ability. It could instead the real system to a certain extent. The research in this paper has important value to the engineering practice.
	Design of optical elements for imaging the earth's plasmasphere (EI CONFERENCE) 会议论文 OAI收割 International Symposium on Photoelectronic Detection and Imaging, ISPDI 2007: Optoelectronic System Design, Manufacturing, and Testings, September 9, 2007 - September 12, 2007, Beijing, China 作者: Chen B.; Chen B.; Wang X.-K. 收藏 \| 浏览/下载：37/0 \| 提交时间：2013/03/25 Studying the distribution of He+ in Earth's plasmasphere by detecting its resonantly-scattered emission at 304A will record the structure and dynamics of the cold plasma in Earth's plasmasphere on a global scale. EUV imaging systems usually utilizes near normal incidence optics including multilayer mirror and filter. In this paper the space condition of the Earth's plasmasphere to confirm the expected performance of mirror and filter for this task were analyzed and some guidelines for the design of the optical elements were introduced. In order to achieve higher response at 304A and reduce 584A radiation for the optical system a new multilayer coating of Mo/Si with UOx (x=2-3) was developed and it is indicated that promising filter material is Al/C with a nickel mesh. In addition we compute the reflectance of multilayer mirror based on optical constants and the transmission of the filter based on atomic scattering factor. The results show the multilayer mirror has high reflectance of 26.27% at 304 Aand low reflectance of 0.60% at 584A. Finally the conversion efficiency of mirror coupled with filter is 6.88% at 304A and 0.01% at 584 A.
	Support technique of ultra thin mirror in space optics (EI CONFERENCE) 会议论文 OAI收割 2nd International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, November 2, 2005 - November 5, 2005, Xian, China 作者: Ren J.-Y.; Gao M.-H. 收藏 \| 浏览/下载：36/0 \| 提交时间：2013/03/25 With the development of space optical system the technique of ultra thin mirror come forth and is paid more attention because of less difficulty in machining low cost lightweight no disassembly during detecting and maintaining. The key technique takes advantage of deformation of ultra thin mirror as the influence of environment to adjust the surface figure. Its accuracy meets requirement. An analysis method is based on finite element analysis (FEA) and many items including the amount of support points the way of arrangement the optimum design of support component are studied. The finite element method was used to analyze the mirror and some different mirror support schemes. The principal aim of the mirror analysis is to get numbers of support points and the ways of the support. There are three schemes including 12-6-1 12-8-1 and 16-8-1 models. Deformation of deadweight is calculated under the three conditions. The way of 16-8-1 is more suitable than the designs of other two. The support subassembly is amended to meet with the mirror surface RMS in the range of 30m. Deformation of the mirror with support structure has been calculated. The result is 16.52nm lower than a quarter of the wavelength which indicates the feasibility of the support scheme applied to mirror. Theoretical result for the best way of support is presented. The result of analysis shows that requirement surface figure could be met through adjusting support points. It predicts feasibility of the support technique and provides theoretical value for active adjustment in the laboratory. At present support and adjusting experiment of ultra thin mirror is being carried on.