The words---coordination, coordination abilities and coordination training are getting more and more popular among the coaches in different sports. The rhythm makes the movement logical, easy and correct done. The pur...The words---coordination, coordination abilities and coordination training are getting more and more popular among the coaches in different sports. The rhythm makes the movement logical, easy and correct done. The purpose of this study is to determine any difference between the coordination abilities of 10-11 years old gifts practicing basketball and rhythmic gymnastics. In that study, we have tested 40 girls at the age of 10-11 years practicing basketball and rhythmic gymnastic. We have tested them by 7 coordination tests. The results from the tests have been calculated in math-statistic methods and we have used descriptive statistic and t-test by Student with guaranteed probability Pt 〉 95 %. Ten-eleven old girls practicing rhythmic gymnastic have advantage against the girls practicing basketball in all 7 tests examining coordination abilities. The girls practicing rhythmic gymnastic, guaranteed by statistic, have better results in the balance and rhythmic abilities than the girls practicing basketball game. That statement is showing us that at this age the rhythmic gymnastic or elements from rhythmic gymnastic should be used for developing balance and rhythmic ability, which are very important for the basketball game.展开更多
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, Changsh...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.展开更多
Vol.43,No.3,2007 NEXT GENERATION LITHOGRAPHY——IMPRINT LITHOGRAPHY DING Yucheng LIU Hongzhong LU Bingheng LI Dichen (State Key Laboratory of Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 71004...Vol.43,No.3,2007 NEXT GENERATION LITHOGRAPHY——IMPRINT LITHOGRAPHY DING Yucheng LIU Hongzhong LU Bingheng LI Dichen (State Key Laboratory of Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China) 1展开更多
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 mode...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.展开更多
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 Technol...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展开更多
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;Fau...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展开更多
Vol. 47, No. 11, 2011 DOI: 10.3901/JME.2011.11.001 Linear Motion Control of Two-pendulums- driven Spherical Robot 1 ZHAO Bo WANG Pengfei SUN Lining LI Mantian (State Key Laboratory of Robotics and System, Harbin Inst...Vol. 47, No. 11, 2011 DOI: 10.3901/JME.2011.11.001 Linear Motion Control of Two-pendulums- driven Spherical Robot 1 ZHAO Bo WANG Pengfei SUN Lining LI Mantian (State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150080, China)展开更多
Basic Principles, Main Characteristics and Development Tendency of Methods for Robot Mechanism Structure Synthesis Abstract： Basic principles and characteristics of three structural synthesis methods （based on scre...Basic Principles, Main Characteristics and Development Tendency of Methods for Robot Mechanism Structure Synthesis Abstract： Basic principles and characteristics of three structural synthesis methods （based on screw theory, displacement subgroup and position orientation characteristics（POC） respectively） for robot mechanism are described and compared. This comparative study shows that the method based on POC has the following notable advantages：展开更多
Kenya Airways is the pride of the whole African continent.Recently,Kenya Airways announced its after-tax profits for the 2010-11 fiscal yearincreased 73 percent.The airline’s CEO and General Manager Titus Naikuni att...Kenya Airways is the pride of the whole African continent.Recently,Kenya Airways announced its after-tax profits for the 2010-11 fiscal yearincreased 73 percent.The airline’s CEO and General Manager Titus Naikuni attributes the greatest part of展开更多
文摘The words---coordination, coordination abilities and coordination training are getting more and more popular among the coaches in different sports. The rhythm makes the movement logical, easy and correct done. The purpose of this study is to determine any difference between the coordination abilities of 10-11 years old gifts practicing basketball and rhythmic gymnastics. In that study, we have tested 40 girls at the age of 10-11 years practicing basketball and rhythmic gymnastic. We have tested them by 7 coordination tests. The results from the tests have been calculated in math-statistic methods and we have used descriptive statistic and t-test by Student with guaranteed probability Pt 〉 95 %. Ten-eleven old girls practicing rhythmic gymnastic have advantage against the girls practicing basketball in all 7 tests examining coordination abilities. The girls practicing rhythmic gymnastic, guaranteed by statistic, have better results in the balance and rhythmic abilities than the girls practicing basketball game. That statement is showing us that at this age the rhythmic gymnastic or elements from rhythmic gymnastic should be used for developing balance and rhythmic ability, which are very important for the basketball game.
文摘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.
文摘Vol.43,No.3,2007 NEXT GENERATION LITHOGRAPHY——IMPRINT LITHOGRAPHY DING Yucheng LIU Hongzhong LU Bingheng LI Dichen (State Key Laboratory of Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China) 1
文摘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.
文摘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
文摘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
文摘Vol. 47, No. 11, 2011 DOI: 10.3901/JME.2011.11.001 Linear Motion Control of Two-pendulums- driven Spherical Robot 1 ZHAO Bo WANG Pengfei SUN Lining LI Mantian (State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150080, China)
文摘Basic Principles, Main Characteristics and Development Tendency of Methods for Robot Mechanism Structure Synthesis Abstract： Basic principles and characteristics of three structural synthesis methods （based on screw theory, displacement subgroup and position orientation characteristics（POC） respectively） for robot mechanism are described and compared. This comparative study shows that the method based on POC has the following notable advantages：
文摘Kenya Airways is the pride of the whole African continent.Recently,Kenya Airways announced its after-tax profits for the 2010-11 fiscal yearincreased 73 percent.The airline’s CEO and General Manager Titus Naikuni attributes the greatest part of
