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浏览/检索结果: 共22条，第1-10条 帮助

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C-13 signatures of aerosol organic and elemental carbon from major combustion sources in China compared to worldwide estimates 期刊论文  OAI收割
SCIENCE OF THE TOTAL ENVIRONMENT, 2022, 卷号: 810, 页码: 14
作者:  Yao, Peng;  Huang, Ru-Jin;  Ni, Haiyan;  Kairys, Norbertas;  Yang, Lu
  |  收藏  |  浏览/下载：24/0  |  提交时间：2023/12/29
Spatiotemporal Trends of Elemental Carbon and Char/Soot Ratios in Five Sediment Cores from Eastern China Marginal Seas: Indicators of Anthropogenic Activities and Transport Patterns 期刊论文  OAI收割
ENVIRONMENTAL SCIENCE & TECHNOLOGY, 2018, 卷号: 52, 期号: 17, 页码: 9704-9712
作者:  Fang, Yin;  Chen, Yingjun;  Lin, Tian;  Hu, Limin;  Tian, Chongguo
  |  收藏  |  浏览/下载：23/0  |  提交时间：2020/07/08
Influence of low temperature on the surface deformation of deformable mirrors 期刊论文  OAI收割
Chinese Physics B, 2017, 卷号: 26, 期号: 5, 页码: 054215
作者:  You, Juncheng;  Guan, Chunlin;  Zhou, Hong
  |  收藏  |  浏览/下载：25/0  |  提交时间：2018/11/20
Reconstruction of atmospheric soot history in inland regions from lake sediments over the past 150 years 期刊论文  OAI收割
SCIENTIFIC REPORTS, 2016, 卷号: 6, 期号: 0, 页码: 19151
作者:  Xu, BQ (Xu, B. Q.);  Gao, SP (Gao, S. P.);  Tie, XX (Tie, X. X.);  An, ZS (An, Z. S.);  Wilcke, W (Wilcke, W.)
  |  收藏  |  浏览/下载：28/0  |  提交时间：2017/11/10
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：63/0  |  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.  
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 of heliostats field for the scale of 1MW solar power tower plant (EI CONFERENCE) 会议论文  OAI收割
2012 Asia-Pacific Power and Energy Engineering Conference, APPEEC 2012, March 27, 2012 - March 29, 2012, Shanghai, China
作者:  Zhang H.;  Wang Z.;  Wang Z.;  Zhang H.
收藏  |  浏览/下载：32/0  |  提交时间：2013/03/25
The development in basic technology and market strategy of solar thermal power techniques is booming rapidly due to the limited fossil resources and severe environmental problems all over the world. In this paper  the design method of heliostats field for the scale of 1MW solar power tower plant with latitude of 40.4N at the design point of the noon of spring equinox is introduced  which uses the multiplication of three efficiencies of cosine  atmospheric transmittance and intercept as the preliminary boundary limit to locate heliostats  while the spacing between heliostats is set not only for less shading and blocking  but also for the availability of installation and maintenance of heliostats. Furthermore  its optical performance tested by the software HFLD  is quite good  which has annual average efficiency of 71.36% and design point efficiency of 80%. 2012 IEEE.  
Space optical remote sensor of the CAE thermal control index calculation method (EI CONFERENCE) 会议论文  OAI收割
2011 International Conference on Advanced Design and Manufacturing Engineering, ADME 2011, September 16, 2011 - September 18, 2011, Guangzhou, China
作者:  Li L.
收藏  |  浏览/下载：28/0  |  提交时间：2013/03/25
The thermal control indicators CAE methods of Space optical remote sensor are analyzed in the presented work. We sat up a thermal optical analysis model for space optical remote sensor. By assuming fully covered by in-orbit temperature load  and using the finite element method for thermal deformation analysis  we obtained the optical remote sensor surface deformation and displacement under various thermal loading. Using ZERNIKE polynomial  wave was fitted to obtain ZERNIKE polynomial coefficients which were incorporated into the optical system design. Using CODE V optical calculation software  heat-ray machines under elastic deformation of the system point spread function  transfer function (MTF)  wave front differential (WFE) etc. were calculated. Image quality changes of remote sensors are discussed in variety assumed cases such as temperature loads of quality change. By repeated iteration  critical value of temperature fields meeting the design requirements are obtained for the optical system. Optical indicators were converged to the temperature field indicator  then reasonable indicators of thermal control for remote sensors were obtained. For the thermal control design  this method provided a reliable basis for design. (2011) Trans Tech Publications  Switzerland.  
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.  
New phase measurement method for laser rangefinder (EI CONFERENCE) 会议论文  OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, April 26, 2010 - April 29, 2010, Dalian, China
作者:  Meng Z.;  Meng Z.
收藏  |  浏览/下载：27/0  |  提交时间：2013/03/25
A new phase measurement method is designed and presented by using the technique of signal shifting phase and the technique of signal multiplication for laser rangefinder. The intensity of laser light is modulated by cosine circuit signal  at the same time the cosine circuit signal is thansformed sine signal by the shifting phase technique. Two signals mentioned above are multiplied by received signal from the target respectively  then being transmitted into signal processor after passing through low band filter respectively. The result of phase-shift between the received signal and sent signal is calculated by means of signal processor and time-counter with double frequency of modulation signal. The proposed system is composed of four units such as control and count unit  emitting and receiving unit of laser light  signal processing unit and result display unit. The two most advantages of proposed system over others are its ability of proper isolation which reduces crosstalk and its independency thermal drift. Theoretical calculations and experimental results have shown the accuracy better than 2 mm. 2010 Copyright SPIE - The International Society for Optical Engineering.