Jet dispenser is widely used in microelectronic packaging, semiconductor industry, life science, and rapid manufacturing fields. As the requirement for dispensing accuracy and speed become higher and higher, especially for viscous materials, the traditional mechanisms cannot meet the high precision dispensing. This paper presents a new jetting dispenser using the complaint mechanism with amplifier components to design the dispenser, which gain the motion and force from the elastic deformation of flexible hinges. To describe the mechanical property of the jetting dispenser, the model of the jetting dispenser was built by employing a pseudo-rigid-body method. To predict accurately droplet volume, we established the model by describing the forming process of droplet. Furthermore, the errors of the droplet volume were analyzed based on the model. The prototype of the dispenser was built and the effects of driving voltage, radius of spray chamber, glue supply pressure, glue viscosity, and turn-on time of hammer on the droplet were analyzed experimentally. The analytical results are in good agreement with experimental results, which the advantages of the presented jetting dispenser with a new design concept are validated. This research provided a new idea and modeling method for the future application of the dispensing system.

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At present top coal caving is done by workers at the fully mechanized top-coal caving face, where the production rate is low and the workers' safety is under threat. In order to reduce the casualties, realize "less people" even "no people" and the high-efficient and high-yield of coal mine, the coal and rock character recognition was researched on underground, the method based on the wavelet packet frequency band energy analysis, for coal and rock identification was proposed. Using the self-developed mine portable vibration data recorder to pick up the vibration signals at the hydraulic support tail beam under the different conditions of coal caving, gangue caving and roof rock caving in the fully mechanized top-coal caving face. The conclusion has been drawn after analyzing the vibration signals by the wavelet packet frequency band energy: When coal caving, the Edge band focus on 1250 Hz~1562.5 Hz and 2187.5 Hz~2500 Hz, when gangue caving, the Edge band focus on 0~625 Hz and 937.5~1250 Hz, when roof rock caving, the Edge band focus on 1875~2187.5 Hz and 3750~4062.5 Hz. The result shows that different edge bands under the different conditions can be used as the criterion for the coal and rock character recognition in the fully mechanized top-coal caving face. And research results could provide a new idea and the method for the coal and rock character recognition.

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Abstract. In high-speed train, since parts of driving medium are not fully rigid, it is common to have fluctuation of rotating speed in different sizes and phase leading to shaft torsional vibration in driving devices for kinds of reasons. Slight vibration can change the torsional stress on axis, which aggravate axial fatigue damage and decrease the service life, severe vibration may result in shaft damage, which have effect on operation security of the train. This paper firstly established two-mass model of drive system and got the transfer function, introduced the mechanism of torsional vibration through theoretical analysis, which proved that torsional vibration is a system stability problem. Then the author established the Simulink model of traction drive system, which proved unstable factor like speed step and load disturbance can result in shaft torsional vibration phenomenon. Finally analyzes influence parameters of vibration frequency and amplitude by simulation.