中国科学院机构知识库网格系统: 检索

Effect of Zn doping on the hydrogenolysis of glycerol over ZnNiAl catalyst 期刊论文 OAI收割
journal of molecular catalysis a-chemical, 2014, 卷号: 395, 页码: 1-6
Li, Xiaoru; Zhang, Chao; Cheng, Haiyang; He,Limin; Lin,Weiwei; Yu,Yancun; Zhao,Fengyu

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Nickel based catalyst is of interest in the industrial catalytic processes and it is always modified by doping a second element to improve its catalytic properties. Understanding the role of dopant is extremely helpful in tailoring the active centers. In this work Zn could induce a significant improvement of the catalytic performance of NiAl for the hydrogenolysis of glycerol. The Zn doped ZnNiAl catalysts exhibited high activity and the improved selectivity to 1 2-propanediol it was about 2 times higher than the original ones. The ZnNi alloy formed in ZnNiAl was responsible for the noticeable catalytic performance. They preferred to coordinate with the end hydroxyl group of glycerol promoted the cleavage of C-O bond in glycerol and resulted in the dominant formation of 1 2-propanediol. The findings described here will provide a useful knowledge for rational design of nickel-based catalysts as well as reveal a new reaction model for the hydrogenolysis of glycerol. (C) 2014 Elsevier B.V. All rights reserved.

Tracking Control of a Closed-Chain Five-Bar Robot With Two Degrees of Freedom by Integration of an Approximation-Based Approach and Mechanical Design 期刊论文 OAI收割
IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART B-CYBERNETICS, 2012, 卷号: 42, 期号: 5, 页码: 1470-1479
作者: Cheng, Long; Hou, Zeng-Guang; Tan, Min; Zhang, W. J.

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Adaptive backstepping closed-chain robot design neural network tracking transient performance.

Trajectory tacking control of a quad-rotor based on active disturbance rejection control (EI CONFERENCE) 会议论文 OAI收割
2012 IEEE International Conference on Automation and Logistics, ICAL 2012, August 15, 2012 - August 17, 2012, Zhengzhou, China
Gong X.; Tian Y.; Bai Y.; Zhao C.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

The objective of this paper is to deal with a trajectory tracking of a Quad-rotor unmanned aerial vehicle (UAV). For the model uncertainty the external disturbance and the coupling factor are considered an active disturbance rejection control (ADRC) algorithm is introduced into the designing procedure. The aircraft dynamic model is proposed in this article based on which the closed-loop control system is divided into four independent channels with the coupling factor compensated by the extended state observer (ESO). The nonlinear state error feedback (NLSEF) algorithm is designed in each channel to improve the closed-loop dynamics. In this article the ADRC controller is expressed in the discrete form. And finally the simulation results show that the proposed control algorithm achieves a favourable tracking performance. 2012 IEEE.

Trajectory tracking control for mobile robot based on the fuzzy sliding mode (EI CONFERENCE) 会议论文 OAI收割
10th World Congress on Intelligent Control and Automation, WCICA 2012, July 6, 2012 - July 8, 2012, Beijing, China
Xie M.-J.; Li L.-T.; Wang Z.-Q.

收藏 | 浏览/下载：26/0 | 提交时间：2013/03/25

The trajectory tracking control problem of the uncertain mobile robot with nonholonomic constraints is analyzed. Sliding mode control is presented based on the kinematics models analysis. Switching function of sliding model control is designed according to back-stepping method. Trending law control is selected to improve the system dynamic performance. In order to solve the constant speed problem caused by conventional trending law control fuzzy control is used to adjust trending speed in the real time. The simulation results demonstrate that the fuzzy sliding mode controller improves the rapidity of trajectory tracking and reduces the tracking error and the chattering of the control output. 2012 IEEE.

AUTONOMOUS INTEGRATED NAVIGATION USING X-RAY PULSARS AND ASTEROIDS 会议论文 OAI收割
63rd International Astronautical Congress 2012, IAC 2012, Naples, Italy, 2012
Yang Chengwei; Gao Dong; Zheng Jianhua

收藏 | 浏览/下载：39/0 | 提交时间：2014/04/30

To improve the navigation performance of the spacecraft during interplanetary cruise a novel integrated navigation system is proposed. For X-ray pulsar navigation (XNAV) is a hot and prospective research subject and the optical navigation using asteroids is practical in space engineering we designed an autonomous navigation system using one X-ray detector and one navigation camera. The measurement models of the XNAV based on the time difference of arrival and the optical navigation based on the images of asteroids are presented. To enhance practicality the X-ray pulsars and asteroids are observed by turns. The batch least square filter used by Deep Space I is adopted to estimate the system state. The numerical simulation results show that the integrated navigation is feasible on the interplanetary cruise orbit. Moreover compared with the XNAV and the optical navigation the integrated navigation system can provide higher navigation performance.

A hybrid median filter for enhancing dim small point targets and its fast implementation (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Multimedia and Signal Processing, CMSP 2011, May 14, 2011 - May 15, 2011, Guilin, Guangxi, China
Yang Q.

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Weak stars and middle altitude orbit satellites or high altitude orbit satellites are presented as dim point targets in images of astronomical observation. They have low intensity and occupy few pixels in image. In most situations the background of sky is always ununiform and there exists pulse noises. Thus results in targets submerging in background noises and low signal noise ratio (SNR). Median filter is an effective method for removing pulse noise. But it can blur image after modifying gray of non-noise pixels when image has low SNR. A hybrid median filter algorithm is proposed to process low SNR dim point targets image. The newly proposed method can suppress the pulse noises also can increase target $SNR$ and does not add extra fake targets. The time complexity of median filter is O(N2)(N is the widow size) and is difficult to implement in hardware. For quasi real time application a fast implementation of our hybrid median filter is proposed to reduce the time complexity to O(N). Experimental results show that the newly proposed algorithm is superior to ordinary median filter and fast median filter by comparing visual effect and performance. 2011 IEEE.

Design and simulation of CMOS star sensor lens with large relative aperture and wide field (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Electronic and Mechanical Engineering and Information Technology, EMEIT 2011, August 12, 2011 - August 14, 2011, Harbin, China
Zhong X.; Jin G.

收藏 | 浏览/下载：60/0 | 提交时间：2013/03/25

A 50mm focal length F/1.25 Gaussian type optical system is designed in this paper which has 20field of view. Actual star image adding optical cross-talk effect of CMOS(Complementary Metal Oxide Semiconductor) detector is simulated by non-sequential ray tracing in ZEMAX optical design and analysis software to evaluate its performance. The distortion relative to image spot centriod is introduced and calculated by simulated star images which is less than 0.03% of lens in this paper. Thermal adaptability is discussed by opt-mechanic thermal analysis which shows the RMS spot radius of marginal filed changes less than 0.7m under 10C temperature gradient and changes less than 1m during homogeneous temperature changing from 40C to 40C. The results of analyses and simulations show the design of this lens can achieve the requirement of high precision CMOS star sensor well. 2011 IEEE.

The parameter optimization of missile actuator based on spatial RSSR linkage mechanism (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
Ge M.; Han X.; Jia H.

收藏 | 浏览/下载：16/0 | 提交时间：2013/03/25

Analyzed the forms of movement of missile actuator based on spatial RSSR linkage mechanism. To achieve synchronic output of each axis applied the multi-body dynamic application ADAMS to realize its parametric modeling and optimization finally got the appropriate parameters to satisfy the performance. Then researched the parameters affection to synchronic performance completed the initial design of the actuator transmission system. 2011 IEEE.

Energy-consumption-related robust optimization scheduling strategy for elevator group control system (EI CONFERENCE) 会议论文 OAI收割
2011 IEEE 5th International Conference on Cybernetics and Intelligent Systems, CIS 2011, September 17, 2011 - September 19, 2011, Qingdao, China
作者: Wang F.; Wang F.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

Group elevator scheduling (GES) problem is an optimization problem. In this work a robust optimization scheduling method is proposed to solve elevator group control system problem with passenger traffic flow uncertainty. An uncertain optimization model of elevator group scheduling is set up based on considering both energy consumption and waiting time. When considering the uncertainty of passenger traffic flow the model is an uncertain optimization problem. It is tuned into its robust counterpart (RC) based on robust optimization theory. The simulation experiment presents the proposed scheduling method's scheduling performance. 2011 IEEE.

The new approach for infrared target tracking based on the particle filter algorithm (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China
作者: Sun H.

收藏 | 浏览/下载：59/0 | 提交时间：2013/03/25

Target tracking on the complex background in the infrared image sequence is hot research field. It provides the important basis in some fields such as video monitoring precision and video compression human-computer interaction. As a typical algorithms in the target tracking framework based on filtering and data connection the particle filter with non-parameter estimation characteristic have ability to deal with nonlinear and non-Gaussian problems so it were widely used. There are various forms of density in the particle filter algorithm to make it valid when target occlusion occurred or recover tracking back from failure in track procedure but in order to capture the change of the state space it need a certain amount of particles to ensure samples is enough and this number will increase in accompany with dimension and increase exponentially this led to the increased amount of calculation is presented. In this paper particle filter algorithm and the Mean shift will be combined. Aiming at deficiencies of the classic mean shift Tracking algorithm easily trapped into local minima and Unable to get global optimal under the complex background. From these two perspectives that "adaptive multiple information fusion" and "with particle filter framework combining" we expand the classic Mean Shift tracking framework.Based on the previous perspective we proposed an improved Mean Shift infrared target tracking algorithm based on multiple information fusion. In the analysis of the infrared characteristics of target basis Algorithm firstly extracted target gray and edge character and Proposed to guide the above two characteristics by the moving of the target information thus we can get new sports guide grayscale characteristics and motion guide border feature. Then proposes a new adaptive fusion mechanism used these two new information adaptive to integrate into the Mean Shift tracking framework. Finally we designed a kind of automatic target model updating strategy to further improve tracking performance. Experimental results show that this algorithm can compensate shortcoming of the particle filter has too much computation and can effectively overcome the fault that mean shift is easy to fall into local extreme value instead of global maximum value.Last because of the gray and fusion target motion information this approach also inhibit interference from the background ultimately improve the stability and the real-time of the target track. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).