Theoretical Study on the Excited-state Intramolecular Hydrogen Abstraction Reactions of Butanal

The excited-state intramolecular hydrogen abstraction reactions of butanal have been investigated using the CAS-MP2/6-311＋G^＊//CASSCF/6-31G^＊ methods. Calculated results show that the hydrogen transfer induced fluorescence quenching of the n,π^＊-excited state of covalent butanal with three paths： （1） The first path corresponds to direct S0-react reconstitution, which involves the first S1 decay by partial hydrogen atom transfer. （2） The second stepwise mechanism can be viewed as a full hydrogen atom transfer followed by a partial hydrogen atom back transfer, electron transfer （near S1/S0 or S0-TS） and finally a proton transfer to S0-react. （3） On the triplet surface, the surface crossing to the singlet state would be clearly much efficient at the T1/S0 region due to the large SOC value of 8.3 cm^-1. The S0-react decay route from T1/S0 was studied with an intrinsic reaction coordinate （IRC） calculation at the CASSCF level, resulting in the S0-React minimum.

Contents and Abstracts of Journal of Mechanical Engineering ISSN 0577-6686,CN 11-2187/TH

Cooperative Reconfiguration for a Reconfigurable Mobile Robot LIU Tonglin, WU Chengdong, LI Bin, LIU Jinguo （1. State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China; 2. Graduate School, Chinese Academy of Sciences, Beijing 100049, China; 3. School of Information Science ＆ Engineering, Northeast University, Shenyang 110004, China）Abstract： A main characteristic of the reconfigurable mobile robot AMOEBA-1 is that it has diverse configurations, but some reconfigurations are difficult to realize under the influence of ground conditions. A cooperative reconfiguration method is proposed to reduce reconfiguration resistance and enhance the adaptability of the robot to the environment. The mathematical model is established correspondingly. The kinematics and mechanical properties of each section of the robot are analyzed. A part of resistance is transformed into active force of reconfiguration, and transforms are actualized among five specific configurations. Further, the linearization of model based on a perturbation analysis method is used to reduce the computational complexity. Finally, an evaluation criterion is proposed for AMOEBA-I＇s cooperative reconfiguration performance. The validity of the cooperative reconfiguration method is proved by simulations and experiments.

Contents and Abstracts of Chinese Journal of Mechanical Engineering (Chinese Edition),ISSN 0577-6686,CN 11-2187/TH

Vol.43,No.7,2007 NOVEL RECOATING PROCESS WITH DYNAMIC OPTIMIZED BLADE SPEED XU Guangshen ZHAO Wanhua LU Bingheng (1.Department of Mechanical Engineering, Xi’an Polytechnic University,Xi’an 710048,China; 2.Institute of Advanced Manufacturing Technology, Xi’an Jiaotong University,Xi’an 710049,China) In order to improve the recoating quality of piston recoating system and resolve the problem that resin layer thickness increases with the height of object during building process in high-resolution stereolitho- graphy system,a novel recoating process whose blade speed is dynami- cally optimized during building process is proposed.Experiments are carried out to investigate the influence of blade speed and object height on the thickness of resin layer.The mathematical model describing the rela- tionship of recoating layer thickness with object height and blade speed is

Contents and Abstracts of Chinese Journal of Mechanical Engineering (Chinese Edition),ISSN 0577-6686,CN 11-2187/TH Vol. 43,No. 5,2007

EMBEDDED-BASED NETWORK NUMERICAL CONTROL TECHNOLOGY AND SYSTEM ZHOU Zude LONG Yihong LIU Quan (Hubei Digital Manufacturing Key Laboratory, Wuhan University of Technology, Wuhan 430070, China) 1 Abstract:It is indicated that the general-purposed PC-based numerical control (NC) technology suffers from a number of problems, such as mis-match between system resources and application needs, unsuitability of the operating system to real-time control, lack of self-owned

Contents and Abstracts of Chinese Journal of Mechanical Engineering(Chinese Edition),ISSN 0577-6686,CN 11-2187/TH

Method of Conceptual Design of Mechanic Product Driven by Generalized Performance WEI Zhe TAN Jianrong FENG Yixiong (State Key Laboratory of CAD&CG,Zhejiang University, Hangzhou 310027,China) Generalized performance of product is used as an effective tool to drive the whole process of conceptual design of mechanical product. Generalized performance of product is defined by utilizing the deduction of axiom of"object structure"which is combined with"P-E"system.And

Contents and Abstracts of Journal of Mechanical Engineering Vol. 45,No.3～4,2009

Effect of Particles Clustering on the Thermal Properties and Thermal Processes of Dilute Nanofluids WANG Buxuan （The Department of Thermal Engineering, Tsinghua University, Beijing 100084, China）

Contents and Abstracts of Chinese Journal of Mechanical Engineering(Chinese Edition),ISSN 0577-6686,CN 11-2187/TH

Vol.44,No.3,2008 Investigation into Mechanism of Initial Rail Corrugation Formation at a Curved Track JIN Xuesong WEN Zefeng XIAO Xinbiao (Traction Power State Key Laboratory,Southwest Jiaotong University, Chengdu 610031,China) The mechanism of initial rail corrugation formation at a curved track is analyzed with a numerical method.The numerical method consid- ers a combination of a coupling dynamic model of a half railway vehicle and a finite length curved track, Kalker′s theory of three-dimensional elastic bodies in rolling contact,and a material wear model,The Hertzian contact non-linear spring with a unilateral restrain and the non-linear tan- gent creep-force model by SHEN-Elkins-Hydrick are used to couple the vehicle model with the track model.Through the detailed analysis on the dynamic behavior of the vehicle curving and the transient contact geome- try of the wheelset and track,the normal forces,the creepases,the contact point positions,and the contact geometry parameters of the wheels and the rails are obtained.According to the known numerical results the

Contents and Abstracts of Chinese Journal of Mechanical Engineering (Chinese Edition),ISSN 0577-6686,CN 11-2187/TH

Vol.44,No.9,2008 The end effect of empirical mode decomposition that appears when using spline interpolation to get two envelops of the data is dis- cussed.The shortage of ordinary end extending methods is pointed out.An extending method based on trigonometric functions is improved,and the influence of different extending periods,length and value of end point of the data is discussed.A comparison with mirror extending method is made and analyzed.On the basis of the improved method,a new method with exponent sine function extending approach is proposed,which decreases the envelop emanation of end points of extending data,so it can improve the speed and precision of EMD,and simulation is used to prove the effec- tiveness.Results show that the proposed improved extending method can restrain the end effect effectively.

Contents and Abstracts of Chinese Journal of Mechanical Engineering(Chinese Edition),ISSN 0577-6686,CN 11-2187/TH Vol.44,No.5,2008

Vol.44,No.3,2008 Investigation into Mechanism of Initial Rail Corrugation Formation at a Curved Track JIN Xuesong WEN Zefeng XIAO Xinbiao (Traction Power State Key Laboratory,Southwest Jiaotong University, Chengdu 610031,China) The mechanism of initial rail corrugation formation at a curved track is analyzed with a numerical method.The numerical method consid- ers a combination of a coupling dynamic model of a half railway vehicle and a finite length curved track, Kalker′s theory of three-dimensional elastic bodies in rolling contact,and a material wear model,The Hertzian contact non-linear spring with a unilateral restrain and the non-linear tan- gent creep-force model by SHEN-Elkins-Hydrick are used to couple the vehicle model with the track model.Through the detailed analysis on the dynamic behavior of the vehicle curving and the transient contact geome- try of the wheelset and track,the normal forces,the creepases,the contact point positions,and the contact geometry parameters of the wheels and the rails are obtained.According to the known numerical results the rolling

Contents and Abstracts of Journal of Mechanical Engineering ISSN 0577-6686, CN 11-2187/TH

Analysis of Dynamic Performance of 2-RUUS Mechanism,Five-finger Dextrous Robot Hand DLR/HIT Hand II,Orthogonal Experimental Design to Synthesize the Accuracy of Robotic Mechanism

Contents and Abstracts of Journal of Mechanical Engineering ISSN 0577-6686, CN 11-2187/TH

Through the development in the past 20 years, the compliant mechanism has become an important branch of modern mechanisms and is widely applied in such fields as precision engineering and robotics. Although a series of design methods and theories of compliant mechanism have emerged, its design problem is still facing challenge. A comprehensive overview of design methods is provided for compliant mechanisms used for precision applications, usually called flexure mechanisms. Several main approaches to analysis and design of flexure mechanisms, including pseudo-rigid-body model, structural matrix model,

Contents and Abstracts of Journal of Mechanical Engineering ISSN 0577-6686, CN 11-2187/TH

Abstract： There are no closed-form inverse displacement solutions for 6R robots with offset wrists. These robotic offset wrists are classified as side offset, top offset, and front offset. To solve the problem of inverse displacement analysis of 6R robots with front offset wrists, according to the geometric character of robotic mechanisms, the robotic kinematic chain is cut into two branches at the origin of the joint coordinate or at the intersection point of the axes of the adjacent coordinates. In this way, one component of degrees of freedom for the two branches becomes decoupled at the cutoff point, so the relationships among the joint variables can be easily deduced. The transcendental equations containing 6 variables are turned into a nonlinear equation containing 1 variable, and the numerical solution for the inverse displacement analysis is obtained by using one dimensional iterative search,

Contents and Abstracts of Journal of Mechanical Engineering ISSN 0577-6686,CN 11-2187/TH

Review on Key Technology of Hydrodynamic and Hydrostatic High-frequency Motor Spindles XIONG Wanli YANG Xuebing LV Lang YUAN Julong （National Research Center for High Efficiency Grinding, Hunan University, Changsha 410082, China） Abstract： High-speed spindles supported by hydrodynamic and hydrostatic hybrid bearings are widely applied in the field of high-speed precision machine tools due to highrotation accuracy, high dynamic stiffness, high vibration damping and long life. But some technical problems caused by integrated structure and high speed, including temperature rise control and motor performance optimization, are yet to be resolved when the integration of hybrid bearings and motor are developed to meet the requirements of ultra-high speed and ultra-precision machining Also major scientific problems involved in the dynamic and thermal characteristics of hybrid journal bearings and the mechanism of electromagnetic losses of high-frequency motor are to be further studied.

Contents and Abstracts of Chinese Journal of Mechanical Engineering (Chinese Edition),ISSN 0577-6686,CN 11-2187/TH Vol.43,No.9,2007

APPLICATION OF GENERALIZED DYNAMIC MATRIX CONTROL WITH STATE OBSERVER IN POSITION SERVO SYSTEM OF STRIP MILL WANG Yiqun SUN Menghui ZHANG Wei LIU Jian(College of Mechanical Engineering,Yanshan University,Qinhuangdao 066004,China) The structure of the strip mill is complicated,and its control sys- tem becomes more and more precise and intellective.But the PID control strategy,being comprehensively used in the locale,is difficult to satisfy the request of improving the control precision of the strip mill,because the ro- bust is not very well.So the generalized dynamic matrix control was applied to design the predictive controllers in position servo system of strip mill,and strategy of the receding-horizon optimization,and the feedback correction were adopted.The state observer was constructed,which made the control

Contents and Abstracts of Journal of Mechanical Engineering ISSN 0577-6686,CN 11-2187/TH

Recent Research Advances and Expectation of Mechanical Engineering Science in China;Research Progress of Friction Behavior during Powder Forming;Review of Vehicle State Estimation Problem under Driving Situation;Fault Diagnosis Method Based on Acoustic Holography;Effect of Track Structure Parameters on Rolling Contact Stresses of Wheel-rail

Contents and Abstracts of Journal of Mechanical Engineering ISSN 0577-6686, CN 11-2187/TH

Effect of Kinematic Behavior of Caudal Fin on Fishlike Robot Propulsion during Steady Swimming CHEN Weishan XIA Dan LIU Junkao SHI Shengjun （State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150080, China）Abstract： The speed convergence algorithm is applied in the numerical simulation of a fishlike robot in self-propelled swimming. All simulations are started with the body at rest, the swimming speed is dynamically modified to converge to the steady value by verifying the fluid forces during the swimming process. The effects of kinematic behavior of caudal fin on fishlike robot propulsion are numerical investigated in the converged steady speed, while the propulsive mechanism and flow field structure are revealed. The results show that the steady speed can be predicted validly by using the speed convergence algorithm, while the relation between the kinematic behavior and the propulsion, power consumption and propulsive efficiency can be obtained through varying the phase difference and the maximum angle of attack. The effects of kinematic behavior of caudal fin on the wake structure and wake strength are clearly reflected in the three dimensional flow field structures. The fmdings are of great significance to the swimming speed prediction, effect of kinematic behavior on fishlike robot propulsion as well as the motion narameter design for fishlike robot

Contents and Abstracts of Journal of Mechanical Engineering ISSN 0577-6686,CN 11-2187/TH

Research on Environment Test Voltage Loading Method of Electrical Connector in Vacuum For problems that different voltage loading method of electrical connector produces different electric field, the calculation model and method of electric field are set up with the electrostatic field theory in view that the decrease or breakdown of insulation resistance and dielectric strength induced by surface fiashover cause failure of electrical connector in vacuum. Then in order to quickly and accurately evaluate the insulation life of electrical connector in vacuum environment, the optimized mathe- matical model of electric field is established nnder the condition of rated voltage by regarding the largest electric field and the most uniform electric field as objectives. Through extracting comprehensive evaluation function from the objectives by using signal-to-noise ratio of electric field, genetic algorithm is used to optimize the voltage loading method by converting multi objective to single objective. The optimal results show that the electric field not only increases about 50%, but also is more uniform, which provides the reference for the reliability evaluation of electrical connector in vacuum.

Contents and Abstracts of Journal of Mechanical Engineering ISSN 0577-6686, CN 11-2187/TH

Sensitivity Analysis of Cup-shaped Flexible Gear Parameters to Its Stress Based on ANSYS