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人文与经济地理学的发展和展望 期刊论文  OAI收割
地理学报, 2020, 卷号: 75, 期号: 12, 页码: 2570
作者:  
陆大道;  刘彦随;  方创琳;  陈明星;  王姣娥
  |  收藏  |  浏览/下载:28/0  |  提交时间:2021/03/15
人文与经济地理学的发展和展望 期刊论文  OAI收割
地理学报, 2020, 卷号: 75, 期号: 12, 页码: 2570
作者:  
  |  收藏  |  浏览/下载:32/0  |  提交时间:2021/03/15
Chinese human geography and its contributions SCI/SSCI论文  OAI收割
2016
作者:  
Fan J.
收藏  |  浏览/下载:36/0  |  提交时间:2016/12/16
Chinese human geography and its contributions SCI/SSCI论文  OAI收割
2016
作者:  
Fan J.
  |  收藏  |  浏览/下载:28/0  |  提交时间:2017/11/09
Effect of gimbal point displacement on optical axis pointing precision in an image seeker (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:  
Zhang X.;  Zhang X.;  Zhang X.
收藏  |  浏览/下载:39/0  |  提交时间:2013/03/25
A concentric glass spherical dome was usually chosen as the transparent window mounted in front of the optical lens in an image seeker. However  optical ray had to change its direction when propagating through the dome due to refraction unless passing through the center of the dome  which demanded gimbal point coincide with the center of the dome exactly. In fact  gimbal point displacement could not be eliminating due to fabrication  assembly and vibration  therefore the optical axis pointing error generated. In this paper  the effect of gimbal point displacement on optical axis pointing precision in an image seeker was analyzed  and the theoretical expression of the optical axis pointing error was derived based on geometric optics  and the error dynamics was explored by numerical. Take a visible light image seeker as a case  the thickness of concentric glass spherical dome was 8mm and the inner radius was 72mm  and the optical axis pointing errors varying dynamically with the look angle and the gimbal point displacement were shown in graph. When the gimbal displacement was 0.11mm  the maximum optical axis pointing error was 0.054mrad that is equal to the instantaneous field of view (IFOV) corresponding to the camera system whose focal length was 120mm and pixel size was 6.5m. Furthermore  with the gimbal displacement increasing  the optical axis pointing error increased linearly. The analyzed results provided a theoretical basis for the displacement range  which had to be limited strictly in the gimbal design process. 2011 IEEE.  
Design of ground-based physical simulation system for satellite-borne TDI-CCD dynamic imaging (EI CONFERENCE) 会议论文  OAI收割
Optoelectronic Imaging and Multimedia Technology, October 18, 2010 - October 20, 2010, Beijing, China
作者:  
Zhang L.;  Zhang L.;  Sun Z.
收藏  |  浏览/下载:25/0  |  提交时间:2013/03/25
As we know  the existence of image motion has a bad effect on the image quality of satellite-borne TDI CCD camera. Although many theories on image motion are proposed to cope with this problem  few simulations are done to justify the proposed theories on ground. And thus  in this paper  a ground-based physical simulation system for TDI CCD imaging is developed and specified  which consists of a physical simulation subsystem for precise satellite attitude control based on a 3-axis air bearing table  and an imaging and simulation subsystem utilizing area-array CCD to simulate TDI CCD. The designed system could realize not only a precise simulation of satellite attitude control  whose point accuracy is above 0.1 and steady accuracy above 0.01/s  but also an imaging simulation of 16-stage TDI CCD with 0.1s its integration time. This paper also gives a mathematical model of image motion of this system analogous with satellite-borne TDI CCD  and detailed descriptions on the principle utilizing area-array CCD to simulate TDI CCD. It is shown that experiment results are in accordance with mathematical simulation  and that the image quality deteriorate seriously when the correspondence between the image velocity and signal charges transfer velocity is broken out  which suggest not only the validity of the system design but also the validity of the proposed image motion theory of TDI CCD. 2010 SPIE.  
Novel method for optimizing polishing tool-path in CCOS based on weighted-iterative algorithm (EI CONFERENCE) 会议论文  OAI收割
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies, November 19, 2008 - November 21, 2008, Chengdu, China
作者:  
Zhang X.-J.;  Wang X.;  Wang X.;  Wang X.;  Wang X.-K.
收藏  |  浏览/下载:47/0  |  提交时间:2013/03/25
In Computer Controlled Optical Surfacing (CCOS)  polishing tool-path is the base of solving other control parameters such as dwell time. In order to improve the fabrication results of polishing off-axis aspheric  a novel method to optimize the tool-path is discussed in this paper. The optimizing method named weighted-iterative algorithm is according to the balance principle of the particle system. The power factor of each dwell point represents the requirement of dwell density. Considering the factors which influence the polishing result  the power factors cosist of three elements include constant  error distribution and dwell distance of workpiece edge. The tool-path is solved by numerical iterative method. In the end  an error data is simulated with actual parameters using the matrix-based algorithm with two different tool-paths. The one is X-Y uniform spacing model and the other one is to optimize it based on the first. The comparison shows that the results of the optimized one are much better than traditional one  especially the rms convergence rate. Theory of the algorithm is simple and exercisable  and it satisfies practical requirement as well. 2009 SPIE.