Advanced Materials Research Vol. 1014

Abstract: In view of the high efficiency modernization coal demand, in this paper, the hydraulic support moving velocity influence factors were studied. Building simulation model of the thrust jack of hydraulic support with the simulation software AMESim, and run the simulation. Comparing the simulation results by setting different parameters value. It is concluded that the rated flow of pump station and hydraulic controlled check valve opening quantity will affect the speed of hydraulic support moving frame. This result provides reference for the optimal design of hydraulic support and improving the efficiency of coal mining. Key words: Moving velocity of hydraulic support; Rated flow; Hydraulic controlled check valve; AMESim 1 Tntroduction In the process of coal mining,the movement of hydraulic support needs in a timely manner with coal mining progresses, thrust jack plays a vital role for the movement of the hydraulic support. Therefore, it is very meaningful to research the influence factors of hydraulic support moving velocity With thrust control loop as the breakthrough point . 2 The working principle of the thrust control loop The movement of the hydraulic support and push the slide are achieved by thrust jack. Thrust jack is located in the middle part of the base of the hydraulic support, its end hinged with the base of the hydraulic support, the other end is connected with flexible scraper conveyor. When the hydraulic support moving, uninstall first, then the hydraulic controlled check valve make high pressure liquid into the piston rod cavity of thrust jack, the liquid in piston chamber flow back. At the same time, make thrust jack cylinder to move forward with the support of conveyor, thus, the whole hydraulic support is pulled to the coal wall, to complete the move. when pushing the slide, make high pressure liquid into the piston chamber , the liquid in piston rod cavity flow back, and, make the piston rod out with the support of hydraulic support. so,the conveyor is pushed to the coal wall,it is completed.

Abstract: Water hammer can occur in any fluid pipeline systems. The pressure caused by water hammer are far exceeding the pressure range of the pipe limit, and it can lead to the failure or fracture of the pipeline. Since a great loss has been caused by that, two influence factors (flow velocity and roughness of the pipe-wall) associated with water hammer have been performed by using the numerical simulation software CFX. Analysis of the results show that each factor effects differently in waveform, amplitude, period, attenuation of the water hammer wave. The different velocities only influences the peak of pressure wave but not the waveform and period. The pressure reduction as the increase of roughness can be neglected compared to the normal pressure.

Abstract: This paper used software Solidworks to build 3-D model of a certain Heavy Vehicle Part, then analyzed the model strain state under typical operation condition by ANSYS. The simulation of the part provides the basis for the structural design.

Abstract: This article addresses the design of ROPS model with energy absorbing structure based on dimensions of cross-section, mechanic properties and deformation pattern of ROPS. Afterwards, optimized buffer and energy-absorbing elements are installed on hexastyle ROPS of certain loader where roll-over accident can be simulated. Results indicate such structure can offer significantly improved protection. Installation of buffer and energy absorbing elements will not only absorb vast amount of motion during roll-over, but also will reduce deformation to ROPS. This has well coordinated the conflict between required rigidity and energy absorbing.

Abstract: In the paper, the three-dimension model of the naval gun including barrel, cradle, bracket .etc has been built in the environment of Pro/E, which Provides the necessary conditions for the building of the dynamics equivalent mode. Then, finite element analysis software ABAQUS had been used to create the finite element model of the naval gun. Apply the above model to simulate the process of shooting with an angular altitude of zero. The characteristics of structural dynamics response of the gun are obtained through analysis. Through the comparison from the result, the stiffness and strength of the naval gun is verified and the basis to improve the firing accuracy is provided. With the method of this thesis, much work such as verifying scheme, finding design bug, verifying firing accuracy, evaluating stiffness and strength of the gun can be done through simulation in the stage of gun design, then period of design is shorted and cost of design is also reduced.

Abstract: When the missiles which were located along ship broadsides were firing, high-temperature and high-pressure jet gas was generated. Because of the limit space of ship, gas jet impact on the deck and hull. It’s very important to avoid or mitigate the influence. This article simulates the jet gas’s impact and ablation on hull and deck and then calculates heat transfer effects on deck. The result can offer certain reference data to optimal design and protection of deck.

Abstract: This article puts forward improved hill-climbing algorithm based on the problems that exist in wind power system compared with traditional hill-climbing searching MPPT control algorithm.In order to obtain optimum power curve,the improved algorithm finds the maximum power point when wind speed is steady firstly,then estimating torque loss accurately of motor to calculate system power loss indirectly when system is in the state of maximum power point.At last,the disturbance step is adjusted in real time based on distance between actual work point and optimum power curve.The improved hill-climbing algorithm does not exist the phenomenon that there is concussion near the maximum power point.What is more, the tracking direction could not be misled and tracking speed is sooner for tracking maximum power point when wind speed changes rapidly.By using Matlab for algorithm simulation,the result shows that improved hill-climbing algorithm could make up for the deficiency of traditional algorithm effectively.

Abstract: Germanium-rich silicon-germanium (Si_1-xGe_x: 0.98≤x≤1) films were epitaxially grown on Si (001) substrate by reactive thermal chemical vapor deposition at low temperature. Si₂H₆ and GeF₄ were used as source gases. The effect of gas flow ratio between Si₂H₆ and GeF₄ was studied to optimize the film quality. The results indicated that Si_1-xGe_x (x≥0.99) epilayer can be prepared directly on Si wafer at 350°C with a threading dislocation density of ~7×10⁵/cm² and surface RMS roughness of 1.0 nm. Hall-effect and conductivity measurements revealed that the epilayer was p-type conduction with the hall mobility of 767 cm²/Vs and the hole concentration of 6.08×10¹⁶/cm³. Those results indicated the Ge-rich Si_1-xGe_x was an excellent candidate for bottom cells of multijunction solar cells.

Abstract: In this paper, an automatic testing platform was developed. A complete charging and discharging cycle for the series-connected lead-acid batteries is carried out by the testing platform to record the capacity, charging efficiency, and other relative data of the batteries. A microcontroller unit (MCU) is used to replace the common DAQ card for cost reduction. The voltage and current of the batteries are sampled by the MCU and saved by the software LabVIEW on the personal computer. The charging and discharging procedures are automatically switched by the software LabVIEW according to the state of the batteries. A complete testing data can be provided by the LabVIEW at the end of the testing cycle. New and old battery modules are both tested with the proposed platform and another reliable testing system to evaluate the validity of the proposed system.

Abstract: Different heating has an important influence on the efficiency of the production casting. Electromagnetic induction heating technology is a new heating technology. Metallic materials is heated itself directly through the Eddy current effect with the high-frequency electric heating principle. Because of its concentrated heat, high power density and high thermal efficiency, it has more superiority than the current conventional electric furnace heating technology. In this paper, the electromagnetic induction heating system has been designed, and this heating method is applied to the casting production. The results show that the electromagnetic induction heating is very suitable for casting production, which can greatly shorten the production time and improve productivity.