中国科学院机构知识库网格系统: 检索

浏览/检索结果: 共8条，第1-8条

帮助

条数/页：排序方式：
	A systematic study on linear thermal expansion coefficient of metals based on interferometric measurement with Fresnel bimirror 期刊论文 OAI收割 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, 2024, 卷号: 66, 期号: 5 作者: Lu, Sifan; Zhao, Wenyu; Lin, Jia; Zhao, Xiaorui; Xu, Ruoyu \| 收藏 \| 浏览/下载：13/0 \| 提交时间：2024/08/19 Fresnel bimirror interference linear thermal expansion coefficient self-programming the finite-method simulation
	On the time evolution of brightness, volume and height of a coronal source in an M-class flare 期刊论文 OAI收割 ASTROPHYSICS AND SPACE SCIENCE, 2017, 卷号: 362, 期号: 6, 页码: 10 作者: Firoz, Kazi A.; Gan, W. Q.; Li, Y. P.; Rodriguez-Pacheco, J.; Su, Y. \| 收藏 \| 浏览/下载：14/0 \| 提交时间：2019/04/08 Solar flares Area/volume of the flare Volume and mean intensity Heights of the coronal sources Total Thermal electrons in high-temperature plasma in the corona contribution into the flare process Adiabatic expansion Theoretical model for thermal source RHESSI X-ray GOES X-ray SDO/AIA images Spatial and temporal evolution of the coronal source RHESSI image reconstruction algorithm
	Study on ultra-light secondary baffle for coaxial two-mirror telescope (EI CONFERENCE) 会议论文 OAI收割 2012 9th IEEE International Conference on Mechatronics and Automation, ICMA 2012, August 5, 2012 - August 8, 2012, Chengdu, China 作者: Zhang L.; Zhang L. 收藏 \| 浏览/下载：62/0 \| 提交时间：2013/03/25 The coaxial two-mirror telescope consists of two mirrors facing each other. Classical two-mirror arrangements are Gregorian and Cassegrain. These systems are usually applied to space telescopes and often have optical baffles to prevent stray light from entering the focal plane. The optical baffles consist of concentric rings suspended between the secondary and the primary mirror. The secondary baffle for a large two-mirror optical system is designed and analyzed in this paper. According to mission of a telescope the structure should have high stiffness and high reliability and light weight. Compared with invar aluminum alloy and titanium alloy carbon fiber composite is currently the best material in terms of weight-to-strength ratio. It also has advantages of high temperature tolerance and low thermal expansion. So carbon fiber composite is chosen as material to meet requirements of the coaxial telescope. In this paper optimization method based on finite element analysis (FEA) is used for design the secondary baffle. Minimum weight of the baffle is chosen as an objective function. Thicknesses of former tube and vanes are chosen as variables. Analysis results show that the designed secondary baffle has maximum diameter of 180mm total length of 120mm and weighs 142g. And its fundamental frequency reaches 651Hz. Therefore the baffle has many advantages such as ultra-light weight high stiffness and dimensional stability etc. The optimization method and the baffle design can be helpful to other coaxial telescopes such as Cassegrain Gregorian and their subdivisions. 2012 IEEE.
	Design and test of pointing mirror assembly for spaceborne remote sensing camera (EI CONFERENCE) 会议论文 OAI收割 2011 International Conference on Electronics, Communications and Control, ICECC 2011, September 9, 2011 - September 11, 2011, Ningbo, China 作者: Chen W. 收藏 \| 浏览/下载：35/0 \| 提交时间：2013/03/25 In order to ensure the surface figure of the pointing mirror (460mm long 290mm wide) in spaceborne remote sensing camera Silicon Carbide was selected as the mirror material. The form of composite triangular and rectangular and the combination of open and closed back was explored in the lightweight design. A new kinematic mount and flexible structure in axis is used to hold the mirror around the lateral surface. The structure can minimize distortions induced by coefficient of thermal expansion mismatch among the materials. This eliminates the bending of the integral mount under the weight of the mirror. Optical performance of the mirror was analyzed under gravity load and temperature load using finite element method. Predicted surface figure error based on the removal of bias tilt and power was calculated using an in-house Matlab script for mirrors. The pointing mirror assembly was tested using open loop servo control. And the surface figure was checked using interferometer. Surface figure accuracy is better than 1/30 ( 632.8nm rms). The results show that the kinematic mount induces minimal figure error on the optical surface. 2011 IEEE.
	Application of particulate reinforced aluminum matrix composite in airborne photoelectric turret (EI CONFERENCE) 会议论文 OAI收割 2011 International Conference on Electric Information and Control Engineering, ICEICE 2011, April 15, 2011 - April 17, 2011, Wuhan, China 作者: Wang P. 收藏 \| 浏览/下载：24/0 \| 提交时间：2013/03/25 In order to design and manufacture more excellent airborne photoelectric stable turret modulus of elasticity of 213 GPa and thermal expansion coefficient of 7.9106/K. The frame has decreased the maximum deformation by by 60% and increased the fundamental frequency by 65% as compared with those of aluminum alloy materials a new type of aeronautical material-particulate reinforced aluminum matrix composite (SiC/Al composite) is investigated. Several crucial technologies respectively as shown by finite element analysis results. Those are confirmed by vibration test furthermore. Therefore such as pressureless infiltration technology a significant lightening effect is achieved and the thermal control load is also reduced. The test result indicates that the stable accuracy of the system achieves 19.8rad and the optical-axis parallelism of pay load is 0.1mrad. The research applies the SiC/Al composites to airborne photoelectric platforms interface reaction controls and plate's welding are systematically studied. Then which makes a effective exploration for the new aeronautical material's application. 2011 IEEE. using SiC/Al composites the airborne photoelectric stable turret frame is successfully prepared in density of 2.94 g/ cm3
	Thermal difference analysis and athermalization design of infrared optical system (EI CONFERENCE) 会议论文 OAI收割 Optical Design and Testing IV, October 18, 2010 - October 20, 2010, Beijing, China 作者: Zhang X.; Zhang X.; Zhang X. 收藏 \| 浏览/下载：32/0 \| 提交时间：2013/03/25 When infrared optical system works in a large temperature range the thermal effect of optical lens and optical tube will produce image plane shift and lead to imaging quality deterioration. In order to eliminate the thermal aberration the athermalization design principles of infrared optical system were introduced and some commonly used methods of thermal difference compensation were described. Proceeding from single lens the thermal difference caused by temperature changing was analyzed and the relationship between temperature and focus shift was obtained. Considering optical tube thermal expansion a set of equations to estimate the thermal difference of lens group was given. Finally an infrared optical imaging system that can work under the temperature range of -40C to 60C was design according to athermal technique in which a new mechanical passive temperature compensation was proposed. Through simulation the athermalization design could make imaging plane shift the smallest. The simulation results coincided with the theoretical formula and the design had reference value in engineering. 2010 Copyright SPIE - The International Society for Optical Engineering.
	Growth, thermal and spectroscopic characteristics of LiNd(WO4)(2) crystal 期刊论文 OAI收割 Optical Materials, 2009, 卷号: 32, 期号: 1, 页码: 69-74 X. Y. Huang, G. F. Wang, X. X. Li, Q. M. Yu and X. D. Lu 收藏 \| 浏览/下载：15/0 \| 提交时间：2012/11/06 LiNd(WO4)(2) crystal Czochralski technique Optical characteristics Thermal properties The specific heat The thermal expansion rare-earth ions laser applications nd-yag fluorescence intensities absorption
	Fabrication technique of large-scale lightweight SiC space mirror (EI CONFERENCE) 会议论文 OAI收割 3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies, AOMATT 2007: Large Mirrors and Telescopes, July 8, 2007 - July 12, 2007, Chengdu, China 作者: Zhang G.; Zhang G.; Zhang G. 收藏 \| 浏览/下载：20/0 \| 提交时间：2013/03/25 Silicon carbide (SiC) is a new type candidate material for large-scale lightweight space mirror. Its low thermal distortion high stiffness high optical quality and its dimensional stability are better than other traditional optical substrate materials such as ULE Zerodure Beryllium (Be) and so on. In this paper the lightweight silicon carbide space mirror blank was fabricated by reaction sintering. As a space born mirror material silicon carbide must be an optical grade ceramic. So we prepared the silicon carbide green body with gel-casting method. Then some carbon materials were supplemented into the green body which will bring reaction-sintering with silicon in a vacuum furnace during 1500-1600C ultimately the reaction bonded silicon carbide was made. The diameter of SiC space mirror blank we have made is 680mm. If expanding the size of the vacuum furnace bigger mirror blank can be obtained. The test results show that the mechanical and thermal properties of RB-SiC are excellent with bending strength of 350MPa fracture toughness of 4.1 MPa·m1/2 and coefficient of thermal expansion(CET) of 2.6710-6/K. The surface roughness(RMS) could be better than 3nm.