CORC

在结果中检索

CORC

浏览/检索结果: 共9条，第1-9条 帮助

限定条件        
已选(0)清除 条数/页：   排序方式：
Fabrication technique of large-scale lightweight SiC space mirror (EI CONFERENCE) 会议论文
3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies, AOMATT 2007: Large Mirrors and Telescopes, July 8, 2007 - July 12, 2007, Chengdu, China
Zhang G.; Zhao R.; Zhao W.
收藏  |  浏览/下载：13/0  |  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.  
Design of dual-FOV refractive/diffractive LWIR optical system (EI CONFERENCE) 会议论文
3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies, AOMATT 2007: Advanced Optical Manufacturing Technologies, July 8, 2007 - July 12, 2007, Chengdu, China
Zhang J.-P.; Wang L.-J.; Zhang X.
收藏  |  浏览/下载：19/0  |  提交时间：2013/03/25
An infrared-optical zoom system using binary element is proposed in this paper. The two main advantages of the zoom system introducing here are: bigger F-number and lower cost. The primary optical properties are: F/#=1  Second  Others  zoom ratio =1:4  binary element is used to correct the chromatical aberration by taking the advantage of negative dispersion characteristics and the cost of the system is lower than that of conventional ones with Zinc Selenide (Znse) material at the same level. In the binary element is rotational symmetric with one step which is easy to fabricate  in order to balance 5th spherical aberration  and dual field are 26.6 and 5.6respectively. Wider field of view is used for search and the smaller one is used for imaging details. This system uses un-cooled infrared detector with 320240 pixels and 45m pixel size. The F-number matches the sensitivity range of the detector array. Three aspects are considered during design process to make the system more satisfactory and more achievable. First  5th coma aberration and 5th astigmatic aberration  the manner of zoom is accomplished by exchanging tow lenses into the smaller field of view system layout. The lens exchange manner faces the requirement of simple system structure and good image quality in both focal points. It can also make the system more feasible in the alignment process than mechanical-zooming manner and optical-zooming manner  high-order asphere surfaces with 2th order to 10 th order are also hired in the system. Asphere surface is useful in compressing the system and improving optical system transmittance. This kind asphere surface is on industrial level featuring low cost and easy to fabricate. It is shown that good image quality can achieved by implementing five Germanium lenses and the transmittance of system is 72%. All aberrations are diffraction-limited  both spherical aberration and astigmatic aberration are corrected. When the field of view(FOV) is 26.6 and the focal length is 152mm  MTF at Nyquist frequency(11lp/mm) is great than 0.7. The spherical aberration is -0.0073. The coma aberration is 0.0978 and the astigmatic aberration is -0.013. When the field of view(FOV) is 5.6 and the focal length is 38mm  MTF at Nyquist frequency is great than 0.8 with spherical aberration -0.0046  the coma aberration 0.055 and astigmatic aberration 0.034.  
Influences of ball-milled time on properties and microstructure of ultrafine WC-10Co cemented carbide 会议论文
China International Conference on Nanoscience and Technology (ChinaNANO 2005), Beijing, PEOPLES R CHINA, JUN 09-11, 2005
作者:  Shi, X. L.*;  Shao, G. Q.;  Duan, X. L.
收藏  |  浏览/下载：6/0  |  提交时间：2019/12/04
Effects of preparation processing on mechanical properties of TiAl intermetallic 会议论文
作者:  Chen, Wenzhe;  Peng, Kaiping;  Qian, Kuang-Wu
收藏  |  浏览/下载：2/0  |  提交时间：2019/11/26
Study of Cu addition on precipitation behaviors and mechanical properties in AA6082 Al-Mg-Si alloy 会议论文
2006 BIMW: 2006 Beijing International Materials Week, Pts 1-4: MAGNESIUM - ALUMINIUM MATERIALS - AEROSPACE MATERIALS - SUPERCONDUCTING AND FUNCTIONAL MATERIALS
作者:  Jin, Man[1];  Li, Jing[2];  Shao, Guangjie[3]
收藏  |  浏览/下载：3/0  |  提交时间：2019/05/10
Effect of iron on the microstructure and mechanical properties of Al-Si alloys 会议论文
TMS 2007 Annual Meeting and Exhibition, 2007-02-25
作者:  Zhang, Henghua[1]
收藏  |  浏览/下载：4/0  |  提交时间：2019/05/10
Nanoindentation characterization of mechanical properties of ferrite and austenite in duplex stainless steel 会议论文
PRICM 6: The 6th Pacific Rim International Conference on Advanced Materials and Processing, 2007-11-05
作者:  Xiufang, Wang[1];  Xiaoping, Yang[2];  Zhendan, Guo[3];  Yinchang, Zhou[4];  Hongwei, Song[5]
收藏  |  浏览/下载：8/0  |  提交时间：2019/05/10
Effect of whisker orientation on mechanical properties of hydroxyapatite-SiCw composite bioceramics 会议论文
5th Asian/Australasian Conference on Composite Materials (ACCM-5), NOV 27-30, 2006
作者:  Niu, Zongwei;  Li, Li
收藏  |  浏览/下载：2/0  |  提交时间：2019/12/31
Effect of superplastic deformation on the properties of zirconia dispersed alumina nanocomposite 会议论文
9th International Conference on Superplasticity in Advanced Materials, Chengdu, PEOPLES R CHINA, 2007-01-01
作者:  Chen, G. Q.;  Sui, S. H.;  Wang, X. D.;  Han, W. B.
收藏  |  浏览/下载：2/0  |  提交时间：2019/12/27

©版权所有 ©2017 CSpace - Powered by CSpace