To study the effect of speed on the biomechanics of a knee joint during running, a biomechanical model of human lower limb joints is established based on the Kane method and semi-physical simulation. Experiments on th...To study the effect of speed on the biomechanics of a knee joint during running, a biomechanical model of human lower limb joints is established based on the Kane method and semi-physical simulation. Experiments on the running process were made at different speeds for healthy young men. The influence of running speed on knee Joint motion is analyzed quantitatively and a mathematical model of the knee angle is established with speed as the independent variable. Results show that, at the moment of the heel contacting with theground, with the increase of speed, the more, and the calf and thigh are closer to the same line. In the middle stage of a gait cycle, the thigh stretches back, and then the calf and thigh are close to collineation. At that moment, the stretch of the posterior cruciate ligament is the largest, and the slower the speed, the more obvious the collineation. The maximal joint angle of the calf relative to the thigh appears in the later stage, and themaximal joint angle increases with the increase of the velocity. With the increase of the running speed, the phase of the cure of knee angle moves forward. The results can be used in the field of rehabilitation robotics and humanoid robot.展开更多
Purpose： The purpose of this study was to determine the effect of horizontal and vertical velocities at the landing of the last step of approach run on the performance and optimal phase ratio of the triple jump. Meth...Purpose： The purpose of this study was to determine the effect of horizontal and vertical velocities at the landing of the last step of approach run on the performance and optimal phase ratio of the triple jump. Methods： Three-dimensional kinematic data of 13 elite male triple jumpers were obtained during a competition. Computer simulations were performed using a biomechanical model of the triple jump to determine the longest actual distance using the optimal phase ratio with altered horizontal and vertical velocities at the landing of the last step of approach run. Results： The actual distance obtained using the optimal phase ratio significantly increased as the horizontal velocity at the landing of the last step of approach run increased （p = 0.001） and the corresponding downward vertical velocity decreased （p = 0.001）. Increasing horizontal velocity at the landing of the last step of approach run decreased optimal hop percentage and increased optimal jump percentage （p = 0.001）, while decreasing corresponding downward vertical velocity increased optimal hop percentage and decreased optimal jump percentage （p = 0.001）. Conclusion： The effects of the velocities at the landing of the last step of approach run on the optimal phase ratio were generally small and did not qualitatively alter optimal techniques.展开更多
In this paper, the authors try to export an equation which describes the variation of kinematic viscosity in blends of diesel fuel with biodiesel. Using specific volume of these blends, the authors determine kinematic...In this paper, the authors try to export an equation which describes the variation of kinematic viscosity in blends of diesel fuel with biodiesel. Using specific volume of these blends, the authors determine kinematic viscosity via method ASTM D 445-06 using a capillary glass viscometer in order to study the contribution of quantity of biodiesel and convert the statistical data into mathematic relation as a specific formula, attempting to achieve an empirical evaluation. Trying to accomplish this, the authors studied the way how the values of variables are changed and whether a relation exists using dispersion diagrams. From the graphic depiction, the authors realized that the relation is linear and they proceeded to regression analysis. The analysis extracted the conclusion that the relation was strong and the values of the dependent variable kinematic viscosity was depended on a large percentage of the values of the mixture of fuels.展开更多
In this paper, the consequences of cilia motion are reflected by the CNTs nanoparticles. The problem is expressed in a symmetric channel with ciliated walls. Exact solutions of the governing flow problem are obtained ...In this paper, the consequences of cilia motion are reflected by the CNTs nanoparticles. The problem is expressed in a symmetric channel with ciliated walls. Exact solutions of the governing flow problem are obtained for pressure gradient, temperature and velocities of the fluid. Streamlines for the velocity profile are plotted to discuss the trapping phenomenon.展开更多
基金The National Natural Science Foundation of China(No.51405095)the Fundamental Research Funds for the Central Universities(No.HEUCF160706)the Technological Innovation Talent Special Fund of Harbin(No.2014RFQXJ037)
文摘To study the effect of speed on the biomechanics of a knee joint during running, a biomechanical model of human lower limb joints is established based on the Kane method and semi-physical simulation. Experiments on the running process were made at different speeds for healthy young men. The influence of running speed on knee Joint motion is analyzed quantitatively and a mathematical model of the knee angle is established with speed as the independent variable. Results show that, at the moment of the heel contacting with theground, with the increase of speed, the more, and the calf and thigh are closer to the same line. In the middle stage of a gait cycle, the thigh stretches back, and then the calf and thigh are close to collineation. At that moment, the stretch of the posterior cruciate ligament is the largest, and the slower the speed, the more obvious the collineation. The maximal joint angle of the calf relative to the thigh appears in the later stage, and themaximal joint angle increases with the increase of the velocity. With the increase of the running speed, the phase of the cure of knee angle moves forward. The results can be used in the field of rehabilitation robotics and humanoid robot.
基金partially supported by a research grant from China Sport Administration (No. 2014B057)
文摘Purpose： The purpose of this study was to determine the effect of horizontal and vertical velocities at the landing of the last step of approach run on the performance and optimal phase ratio of the triple jump. Methods： Three-dimensional kinematic data of 13 elite male triple jumpers were obtained during a competition. Computer simulations were performed using a biomechanical model of the triple jump to determine the longest actual distance using the optimal phase ratio with altered horizontal and vertical velocities at the landing of the last step of approach run. Results： The actual distance obtained using the optimal phase ratio significantly increased as the horizontal velocity at the landing of the last step of approach run increased （p = 0.001） and the corresponding downward vertical velocity decreased （p = 0.001）. Increasing horizontal velocity at the landing of the last step of approach run decreased optimal hop percentage and increased optimal jump percentage （p = 0.001）, while decreasing corresponding downward vertical velocity increased optimal hop percentage and decreased optimal jump percentage （p = 0.001）. Conclusion： The effects of the velocities at the landing of the last step of approach run on the optimal phase ratio were generally small and did not qualitatively alter optimal techniques.
文摘In this paper, the authors try to export an equation which describes the variation of kinematic viscosity in blends of diesel fuel with biodiesel. Using specific volume of these blends, the authors determine kinematic viscosity via method ASTM D 445-06 using a capillary glass viscometer in order to study the contribution of quantity of biodiesel and convert the statistical data into mathematic relation as a specific formula, attempting to achieve an empirical evaluation. Trying to accomplish this, the authors studied the way how the values of variables are changed and whether a relation exists using dispersion diagrams. From the graphic depiction, the authors realized that the relation is linear and they proceeded to regression analysis. The analysis extracted the conclusion that the relation was strong and the values of the dependent variable kinematic viscosity was depended on a large percentage of the values of the mixture of fuels.
文摘In this paper, the consequences of cilia motion are reflected by the CNTs nanoparticles. The problem is expressed in a symmetric channel with ciliated walls. Exact solutions of the governing flow problem are obtained for pressure gradient, temperature and velocities of the fluid. Streamlines for the velocity profile are plotted to discuss the trapping phenomenon.
