中国科学院机构知识库网格系统: 检索

Study on the sensitivity of temperature gradient for large aperture SiC lightweight mirror based on active optics 会议论文 OAI收割
7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, AOMATT 2014, April 26, 2014 - April 29, 2014, Harbin, China
作者: Li J.; Zhang J.; Li J.; Li J.; Zhang J.

收藏 | 浏览/下载：14/0 | 提交时间：2015/04/27

Luminescence and energy transfer in Ca3Sc2Si 3O12:Ce3+,Mn2+ white LED phosphors 会议论文 OAI收割
P.O. Box 211, Amsterdam, 1000 AE, Netherlands
作者: Zhang X.; Liu Y.; Zhang J.; Zhang J.; Zhang J.

收藏 | 浏览/下载：36/0 | 提交时间：2014/05/15

Luminescence and energy transfer in Ca3Sc2Si 3O12:Ce3+,Mn2+ white LED phosphors (EI CONFERENCE) 会议论文 OAI收割
作者: Luo Y.; Zhang J.; Zhang J.; Zhang J.; Wang X.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

Expanded emission spectra ranging from green to red are reported in Ca 3Sc2Si3O12 (CSS):Ce 3+ Mn2+ silicate garnets. Mn2+ may occupy Ca2 site (Mn2+(I)) to generate a yellow emission band at 574 nm or Sc3 site (Mn2+(II)) with red emission band at 680 nm. Efficient energy transfers from the green emitting Ce3+ to both Mn2+(I) and Mn2+(II) occur upon blue excitation into Ce3+. Concentration dependence of Mn2+ emission is analyzed based on Ce3+-Mn2+ energy transfer steady state rate equations and fluorescence lifetimes. Energy transfer efficiency (nT) and rate (W) are calculated with values as high as 45% and 14.01106 s-1 respectively. 2011 Elsevier B.V.

Energy transfer from CdSe quantum dots to porphyrin via two-photon excitation 会议论文 OAI收割
25650 North Lewis Way, Stevenson Ranch, California, 91381-1439, United States
An L.; Chao K.; Zeng Q.; Han X.; Yuan Z.; Xie F.; Fu X.; An W.

收藏 | 浏览/下载：10/0 | 提交时间：2014/05/15

Research on satellite platform vibration compensation method based on liquid crystal steering system (EI CONFERENCE) 会议论文 OAI收割
2011 SSITE International Conference on Future Material Research and Industry Application, FMRIA 2011, December 1, 2011 - December 2, 2011, Macau, China
作者: Wen M.

收藏 | 浏览/下载：9/0 | 提交时间：2013/03/25

This paper presents the disturbance compensation scheme based on liquid crystal steering system according to the problem that satellite platform vibration affects the tracking and pointing accuracy in space optical communication. The mathematical model of liquid crystal steering system is built. For improving convergence speed the adaptive controller based on posteriori estimation errors RLS lattice filter is designed which not only achieves fast adaptation but also reaches optimal steady-state disturbance compensation. Finally the simulation results show that this control scheme is valid and feasible. (2012) Trans Tech Publications Switzerland.

Performance test of steel tube enclosed thermistors in air temperature measurements (EI CONFERENCE) 会议论文 OAI收割
3rd International Conference on Measuring Technology and Mechatronics Automation, ICMTMA 2011, January 6, 2011 - January 7, 2011, Shanghai, China
作者: Yang H.; Yan F.; Yan F.; Peng J.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

The performances of two steel tube enclosed precision thermistors are tested in a well controlled air environment to determine if the thermistors have enough accuracy for 0.01C levels of air temperature gradient measurement. Three Fluke's 5641 and three 5610 thermistors were tested for 24 hours in Fluke's 7008 calibration bath in the first step. In the second step the performances of these two thermistors in steady state and transient state air temperature environments were tested for 8 hours separately. The results illustrate that two of the 5641s were airproofed in a temperature well controlled tube when steel tube enclosed precision thermistors are used in air temperature measurement there are unstable departures from each other with a maximum 8.8 mC in constant air medium and 27 mC in temperature changing air medium. The transient-time errors are too large to show the true amounts of temperature changes for air temperature measurement. 2011 IEEE.

The application of the discrete sliding mode control based on state observer in aerial camera (EI CONFERENCE) 会议论文 OAI收割
2nd Annual Conference on Electrical and Control Engineering, ICECE 2011, September 16, 2011 - September 18, 2011, Yichang, China
作者: Zhang X.; Zhang X.; Zhang X.

收藏 | 浏览/下载：10/0 | 提交时间：2013/03/25

A discrete sliding mode control scheme based on state observer is designed for DC torque motor. Aim on the problem of control chattering and steady-state chattering caused by discrete sliding mode control method adaptive reaching law is proposed Non-chattering and stability are made an analysis. The aerial camera is chosen as an experimental platform and the discrete sliding mode controller with adaptive reaching law is applied to the drawtube system the value of acceleration can be observed on line. The experiment results show the control scheme can effectively eliminate chattering and also make the drawtube system achieve better dynamical performance. 2011 IEEE.

An information theoretic approach to model reduction based on frequency-domain Cross-Gramian information (EI CONFERENCE) 会议论文 OAI收割
2010 8th World Congress on Intelligent Control and Automation, WCICA 2010, July 7, 2010 - July 9, 2010, Jinan, China
作者: Zhou J.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

We focused our attention on model reduction for linear time invariant (LTI) continuous time systems with single input and single output (SISO). We analyzed the strongpoint and shortcoming of an information theoretic approach called minimum information loss method for model reduction. We explained relationships between the steady-state information entropy and controllability information for the Gaussian systems. The controllability observability and Cross-Gramian information were analyzed in the time-domain. The frequency-domain Cross-Gramian information (FCGI) was defined based on Cross-Gramian matrix containing information associated with both controllability and observability. Furthermore a valuable application of the frequency-domain Cross-Gramian information to model reduction (FCGMIL) was developed by using the concept and properties of frequency-domain Cross-Gramian information. The performance index of FCGMIL is to minimize the frequency-domain Cross-Gramian information loss caused by eliminating the state variables with weak contributions to Cross-Gramian information over some frequency band. Two numerical examples are illustrated to verify the efficiency of FCGMIL. 2010 IEEE.

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：14/0 | 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 research of control strategy on AOD furnace tilting system (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Logistics Systems and Intelligent Management, ICLSIM 2010, January 9, 2010 - January 10, 2010, Harbin, China
Ma H. T.; You W.; Chen T.

收藏 | 浏览/下载：12/0 | 提交时间：2013/03/25

In view of the low speed the heavy load reversing the frequently brake the intense impact characteristics of AOD furnace tilting system The double closed-loop with feedforward is used. Position regulator and speed regulator use PID algorithm.And the speed loop is designed based on vector control. This control system was simulated by MATLAB Simulink software. The simulation result showed: Adjustment time is 8s the position steady-state error is 0 so it has achieved the demanded target of 0.12 radian static error fully. 2010 IEEE.