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The fundamental plane with radiatively efficient blazars 期刊论文  OAI收割
ASTROPHYSICS AND SPACE SCIENCE, 2018, 卷号: 363, 期号: 12, 页码: 6
作者:  
Zhang, Xu;  Zhang HJ(张皓晶);  Zhang X(张雄)
  |  收藏  |  浏览/下载:24/0  |  提交时间:2019/01/14
A fundamental plane with blazar and gamma-ray burst 期刊论文  OAI收割
ASTROPHYSICS AND SPACE SCIENCE, 2017, 卷号: 362, 期号: 12
作者:  
Zhang X(张旭);  Zhang, Haojing;  Zhang, Xiong;  Xiong DR(熊定荣)
  |  收藏  |  浏览/下载:37/0  |  提交时间:2018/06/04
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:60/0  |  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.  
A design on a control method of a new type of focal plane shutter (EI CONFERENCE) 会议论文  OAI收割
2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China
Xue L.; Ming L.; Zheng L.-N.; Zhou J.-F.; Zhang H.-W.; Zhang J.-C.
收藏  |  浏览/下载:33/0  |  提交时间:2013/03/25
In order to ensure appropriate exposure time  and no exposure while electric charge is transferring after taking a photograph  it is necessary to have the shutter mechanism cooperate with CCD for area CCD aerial cameras. The ground object illumination has a wide range which is from 4000Lx to 100000Lx  so a shutter which is high efficient and a continuous stepless adjustment are also required. This paper introduces the fundamental principle  structural design and control procedure about this new focal plane shutter. Under the control of DSP  the velocity of shutter curtain governed by the shutter motor can be not only precisely controlled  but also the durability and the reliability are increased. The experiment results have shown that this new shutter has the higher stability of movement  long life span with more than 105 operating times  a wide range of exposure time from1/ 50s to 1/ 320s(depending on the slit width)and the exposure error is less than 10%. With the CCD gain adjustment  the performance of this shutter is fully satisfied with the requirements of area CCD aerial cameras. 2010 IEEE.