BIOMECHANICAL STUDY OF THE TRANSmON TECHNIQUE OF EXCELLENT MALE SHOT-PUTTERS

All sports events have undergone many innovations during the 100 years development of Olympic Games. In particular track and field events, ,in which skill development is much more obvious, have been characterized by rapid improvements in human performance. Within the field events, the shot put is a complex event that has prompted many skill innovations from throwing in place to side sliding shot putting, to back sliding throwing, and to rotational shot putting. The outcomes of all these innovations seem to add to the duration of the acceleration phase, which then increase the velocity of release. Because shot put belongs to "cast events", According to trajectory principles, its descriptive mechanical formula is S = v02Sin2a/g with S being affected by the velocity of release. So the key to improving performance in the shot put is to increase its velocity of release. Building of the velocity of the shot begins at the slide stage, and then it passes to the transition stage to transform the velocity into motion of the shot put at release. So skill in the transition phase is very important during throwing the shot put. How to minimize the loss of velocity during the throw is the aim of the present study with a particular emphasis on the transition skill

STUDY ON EQUIPMENT FOR SHOT PUT SOUND SIGNAL FEEDBACK

There are not many articles about the structure of putting, especially on the dynamic study. At present nobody applies instruments and equipments to measure dynamic parameters in the course of putting. The result of this study is to make an electronic pressure device fixed inside a shot. According to non-electric measuring principles, a computer is used to analyze the acquired signals after their amplification, taking sample and NO transmission so as to measure the dynamic parameters that shot-putters have strength on their arms. They may work as theoretical basis of teaching and training. In the meantime they can also help coaches to give technological diagnosis of shot-putters and make a scientific plan of training. Only in this way can shot-putters in China catch the advanced level of the world and win good scores at the Olympic Games

Deformation Analysis of the Glass Preform in the Progress of Precision Glass Molding for Fabricating Chalcogenide Glass Diffractive Optics with the Finite Element Method

Precision glass molding (PGM) technology is a cost-efficient process for the production of micro/nanostructured glass components with complex surface geometries. The stress distribution, surface profile, and reduced refractive index of the molded lens are based on the lens being fully formed. The process of the deformation of the glass preform is rarely discussed, especially in the case of multi-machining parameters in the experiment. The finite element method (FEM) was adopted to analyze the glass preform deformation. Due to the phenomenon of incomplete deformation of the glass preforms in the experiments, two groups of finite element simulations with different boundary conditions were carried out with MSC.Marc software, to reveal the relationship between the deformation progress and the parameters settings. Based on the simulation results, a glass preform deformation model was established. The error between the model result and the simulation result was less than 0.16. The establishment method of the glass preform deformation model and the established model can be used as a reference in efficiently optimizing PGM processing parameters when the designed lens has two different base radii of curvature