中国科学院机构知识库网格系统: 检索

C:N:P stoichiometric characteristics and drivers of surface soil in the drylands of China 期刊论文 OAI收割
ENVIRONMENTAL EARTH SCIENCES, 2024, 卷号: 83, 期号: 9, 页码: 14
作者: Zhang, Shihang; Chen, Yusen; Lu, Yongxing; Guo, Hao; Guo, Xing

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收藏 | 浏览/下载：39/0 | 提交时间：2024/05/28

Nutrient stoichiometry Aridisols Non-linear relationships Spatial distribution Main factors

A catastrophic landslide triggered debris flow in China's Yigong: factors, dynamic processes, and tendency 期刊论文 OAI收割
EARTH SCIENCES RESEARCH JOURNAL, 2020, 卷号: 24, 期号: 1, 页码: 71-82
作者: Li Jun; Chen Ningsheng; Zhao Yuandi; Liu Mei; Wang Weiyu

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收藏 | 浏览/下载：28/0 | 提交时间：2020/04/29

Catastrophic landslide triggered debris flow Dynamic process Main controlling factors Tendency analysis Yigong

Research and optimization on media access control delay of CAN (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Information Technology and Management Innovation, ICITMI 2012, November 10, 2012 - November 11, 2012, Guangzhou, China
作者: Zhang H.; Zhang W.; Zhang W.; Zhang H.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

With data quantity increasing dramatically and signal transmission period becoming more and more fast the media access control delay has proved to be one of the main influence factors of CAN network real-time. Firstly an equivalent numerical simulation model of CAN bus network is built to derivate the mathematical expression of media access control delay. Secondly optimization measures are further proposed to improve the data communication real-time. At last the optimization measures tested by experiments are proved to be correct and effective. (2013) Trans Tech Publications Switzerland.

Precision analysis of simulation systems with hardware-in-loop caused by performance of three-Axis virtual flight motion simulator (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Manufacturing Science and Technology, ICMST 2011, September 16, 2011 - September 18, 2011, Singapore, Singapore
Wang T.; Zhu M.-C.; Yin S.-L.; Jia H.-G.

收藏 | 浏览/下载：54/0 | 提交时间：2013/03/25

Simulation systems with hardware-in-loop are composed by three-Axis virtual flight motion simulator simulation computer load torque simulator and visual simulation systems. Three-Axis Virtual Flight Motion Simulator are used to simulate the attitude of missile in simulation system with hardware-in-loop so its performance influenced the result of simulation directly. This paper mainly analyzed the factors which influenced the performance of a three-Axis virtual flight motion simulator which we are used now in the lab then analyzed the entire simulation system's error caused by these factors through numerical simulation method. By analysis we can see that bandwidth is the main factor influenced the precision of simulation systems with hardware-in-loop mechanical device installation error and measurement error may also cause some errors of the systems at the same time.

Stabilization and tracking precision improved based on disturbance observer (EI CONFERENCE) 会议论文 OAI收割
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011, July 15, 2011 - July 17, 2011, Inner Mongolia, China
Sun G.; Zhu M.; Jia H.

收藏 | 浏览/下载：36/0 | 提交时间：2013/03/25

Based on the kinematics of semi-strapdown seeker the framework coordinate of the semi-strapdown seeker is established and the optical axis stabilization equation of semistrapdown seeker is deduced based on product of exponential (POE) formula. The stabilization control principle block diagram of semi-strapdown seeker is shown based on the stabilization equation. The main influence factors of the stability precision are pointed out such as friction disturbance velocity measurement noise and missile disturbance. For the sake of improving the stabilization precision and tracking precision disturbance observer was proposed in the inner loop of semi-strapdown seeker servo-control system. The low frequency external disturbance and high frequency velocity measurement noise are effectively restrained by the disturbance observer as shown in hardware-in-loop simulation and optical axis stabilization precision and tracking precision are greatly improved. 2011 IEEE.

Optical axis stabilization of semi-strapdown seeker based on disturbance observer (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Information and Automation, ICIA 2011, June 6, 2011 - June 8, 2011, Shenzhen, China
Sun G.; Zhu M.; Yin S.; Jia H.

收藏 | 浏览/下载：28/0 | 提交时间：2013/03/25

Based on the kinematics of semi-strapdown seeker the framework coordinate of the seeker is established. The optical axis stability equation of semi-strapdown seeker is deduced by using attitude transformation matrix. Then the stability control principle block diagram of semi-strapdown seeker is shown based on the stability equation. The main factors that influence the stabilization precision are pointed out such as friction disturbance velocity-measuring noise and missile disturbance. In order to improve the stabilization precision disturbance observer was proposed in semi-strapdown seeker stability control. The low frequency external disturbance and high frequency velocity measurement noise are effectively restrained by the disturbance observer as shown in hardware-in-loop simulation and optical axis stabilization precision is improved nearly 20 times and 5 times due to two different frequencies with same amplitude. 2011 IEEE.

Nonlinear analysis method for predicting optical surface deformations resulted from assembly process (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, April 26, 2010 - April 29, 2010, Dalian, China
Dong W.; Yong Y.; Guang J.

收藏 | 浏览/下载：28/0 | 提交时间：2013/03/25

There are three main nonlinear elements in the large mirror assemblies which are screw pretension adhesive stress and state changes in the assembly process. The optical shape will be influenced seriously by these factors. But the impacts will not be shown in linear analysis results because as the simplification these factors have been ignored. The nonlinear analysis method for predicting optical surface deformations resulted from assembly process is discussed in detail. Take a typical mirror support structure for example the nonlinear analysis model was established. Comparing the calculation results with the optical shape test it is illustrated that nonlinear analysis is more accurate and closer to the test result. And according to the simulation result the bowl-shaped depression which was discovered in the test can also be explained reasonably. 2010 Copyright SPIE - The International Society for Optical Engineering.

Position servo control of a DC electromotor using a hybrid method based on model reference adaptive control (MRAC) (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
作者: Chen J.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

This paper dealed with position control problems of a DC motor servo system that had nonlinear friction and was subject to parametric uncertainties external disturbances etc. In order to overcame those unfavourable factors mentioned above a model reference adaptive control method was proposed to regulate the important and main speed loop in the positioning system which was designed with three closed control loop where a compensatory measure was given so as to counterbalance the friction torque disturbances. In addition the other two close loops were built in adjusting the position and the current of the servo system respectively that aimed to achieve the fast and precise positioning and increase dynamic stiffness against load disturbances. Experimental results illustrate satisfactory performances in steady state error load capability high rapidity and so on. 2010 IEEE.

The automatic photoresist coating machine on the spherical surface (EI CONFERENCE) 会议论文 OAI收割
2009 IEEE International Conference on Mechatronics and Automation, ICMA 2009, August 9, 2009 - August 12, 2009, Changchun, China
作者: Li Y.; Li Y.; Li Y.; Li Y.; Wang H.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

The photoresist coating is an important micro machining process widely applied in engineering. The formed film should be uniform and enough thin to assure the quality of final pattern whose line width is micrometer or nanometer. It is more difficult to process it on the spherical surface than on the flat. In this work mathematic model of film thickness on the spherical surface is proposed by using hydromechanics. The key factors that influence the film thickness are obtained from the analysis of coating process. Then the rational parameters which be controlled by the automatic photoresist coating machine can be final set up according to the result of the coating experiments. And the accuracy analysis of the key part which is used for the main process is performed by the error analytics. This machine not only makes the whole coating process automation but also monitors the film quality in real time. It is adequate for aspheric surface also. 2009 IEEE.

Tectonic subsidence of Qiongdongnan Basin and its main control factors 期刊论文 OAI收割
CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION, 2008, 卷号: 51, 期号: 2, 页码: 376-383
作者: Yuan Yu-Song; Yang Shu-Chun; Hu Sheng-Biao; He Li-Juan

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收藏 | 浏览/下载：24/0 | 提交时间：2018/09/26

Northern South China Sea Qiongdongnan Basin tectonic subsidence main control factors Red River Fault