中国科学院机构知识库网格
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Lightweight design of large scale theodolite's turntable based on topology optimization of continuum structure (EI CONFERENCE) 会议论文  OAI收割
2012 International Conference on Optoelectronics and Microelectronics, ICOM 2012, August 23, 2012 - August 25, 2012, Changchun, China
作者:  
Wang Y.;  Wang Y.;  Wang Y.;  Wang Y.;  Wang Y.
收藏  |  浏览/下载:29/0  |  提交时间:2013/03/25
In order to solve the problem that the weight of large scale theodolite's casting or steel plate welded structure is too heavy  lightweight design of large scale turntable based on topology optimization of continuum structure is investigated. Topology optimization could have better optimization efficiency because it can provide the optimized distribution of material and gain optimized structure in conceptual design phase of the structural design. In order to obtain lightweight and high stiffness structure  a truss turntable based on topology optimization of continuum structure is presented  and the validity of this lightweight structure is examined by finite element analysis. Comparing to the traditional welding steel turntable  the lightweight turntable  without changing the static displacement  can lose 386.48 kg(lightweight ratio is 26.7%)  and its first-order natural frequency raises from 167.02Hz to 173.71Hz. Meanwhile  in other aspects this turntable also has better performance than traditional structure. 2012 IEEE.  
The aircraft autopilot design of parameters changing in a wide range (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
Zhen D.; Yue Z.
收藏  |  浏览/下载:28/0  |  提交时间:2013/03/25
Autopilot is an important part of aircraft  Under the action of the disturbance torque  for the flight parameters of aircraft Changing in a wide range  the range was about 16km  on the basic of analyzing the typical trajectory  the max height was about 5100m  the trajectory of feature points were selected  the deviation of lateral was about 12m  taking pitch control loop for example  the maximum angle of attack was about 3.6  a sub- PID autopilot was designed using classical control theory  the maximum elevator deflection was less than 5  using single-mode Transient suppression method  the maximum aileron deflection was less than 2  the overload due to control surface transition deflection was avoided when control parameters changing  the maximum roll was less than 5  the verification was done by non-linear simulation. The result showed that: the phase margin of autopilot was greater than 30  the response of overload can accurately track the given overload instruction. An autopilot design method of aircraft of parameter changes in a wide range was provided. 2011 IEEE.  the bandwidth was more than 14rad / s  the settling time was less than 0.7s  the maximum overshoot was 23.3%  
Phase characteristics of laser beam in fibers (EI CONFERENCE) 会议论文  OAI收割
5th International Workshop on Adaptive Optics for Industry and Medicine, August 29, 2005 - September 1, 2005, Beijing, China
作者:  
Wang L.;  Wang L.;  Liu J.;  Liu J.;  Liu J.
收藏  |  浏览/下载:30/0  |  提交时间:2013/03/25
The phase changing rates1 of laser beam in single mode polarization maintaining fiber (PMF)  Yb-doped rectangular inner cladding dual-clad fiber (DCF) and Yb-doped large-mode-area dual-clad fiber (LMF) are investigated by means of interference under situations with different exterior disturbance  for situations that all the fibers are used as transmission medium only  as well as amplifying medium with the last two. In this paper  phase fluctuation characteristics of the beam transmitted through the fibers with no amplification are presented. The results show that the phase fluctuation frequencies of the laser beam transmitted through these three kinds of fibers are mainly in the range of 100-200Hz  100-300Hz and 80-400Hz respectively in normal laboratory environment. The phase fluctuation frequencies of the laser beam transmitted through the DCF  in cases of when the environment temperature is changing  a constant pressure is applied to the fiber and when vibration is applied  are mainly in the range of 100-600Hz  100Hz-300Hz and 100-500Hz respectively. In the same cases  for the LMF  the phase fluctuation frequencies are mainly in the range of 150-600Hz  100-400Hz and 100-1000Hz  respectively. It indicates that for realizing phase stabilization  the bandwidth of any potential phase control2 system has to be in the range of a few kilohertz.  
Theoretical frame of the saturated freezing soil 期刊论文  iSwitch采集
COLD REGIONS SCIENCE AND TECHNOLOGY, 2002, 卷号: 35, 期号: 2, 页码: 73-80
作者:  
Li, N;  Chen, FX;  Su, B;  Cheng, GD
收藏  |  浏览/下载:32/0  |  提交时间:2019/10/08
The coupled heat-moisture-mechanic model of the frozen soil 期刊论文  iSwitch采集
COLD REGIONS SCIENCE AND TECHNOLOGY, 2000, 卷号: 31, 期号: 3, 页码: 199-205
作者:  
Li, N;  Chen, B;  Chen, FX;  Xu, XZ
收藏  |  浏览/下载:44/0  |  提交时间:2019/10/08