Applied Mechanics and Materials Vols. 110-116

Abstract: The complexity of the video background of moving target tracking algorithm led to the robustness of the important reasons is not high for the limitations of existing algorithms, a framework based on the movement of particle filter tracking algorithm. In order to reduce the impact of occlusion for the algorithm, the algorithm of moving objects make full use of color and motion characteristics of moving target detection, and to avoid the interference of the complex background, within the framework of particle filter in the object color histogram analysis. Finally, given an effective comparison of the calculation. Experimental results show that particle filter based target tracking algorithm can effectively remove the interference of the complex background, the context for any trace detection of high robustness.

Abstract: The principle of wedge-crystal depolarizer was introduced and an optimal parameters combination of polarization direction, wedge angle, pupil size was obtained by using Mueller matrix. The design of depolarizer should be determined by crystal refraction index, wavelength, and incident pupil size. Calculation and simulation based on software show that degree of polarization (DOP) can be improved by increasing pupil size and wedge angle. Some significant conclusions for the optimized design of parameters were gained for fabricating crystal depolarizers.

Abstract: In order to improve the pyroelectric properties of nanograded ferroelectric films (NGFF), and provide a theoretical reference for practical applications, the generalized Ginzburg-Landau-Denvonshire (GLD) theory is adopted to investigate the pyroelectric properties of the NGFF. A function is introduced to characterize the local structure in nanograded films. Influence of the local structure, film thickness and external electric field on the polarization distribution and pyroelectric properties are mainly discussed. The numerical results show that parameterand film thickness are two very important factors that influence the film properties, larger values lead to smaller spontaneous polarization and lower pyroelectric peak. Different directions of the external electric field can lead to greatly different effects on pyroelectric behaviors, whose effects is to expand the working temperature region, or else, change the order of phase transition.

Abstract: Vertical-Cavity Surface-Emitting Lasers (VCSELs) are a new generation of semiconductor lasers that have many advantages. In this paper, we present a comprehensive circuit-level VCSEL model that addresses the spatial and thermal behavior of VCSELs including turn on delay based on the rate equations without sacrificing the numerical efficiency demanded by the circuit-level simulation of optoelectronic systems. It is implemented into SPICE-like simulators to simulate the dc, ac and transient features (including turn-on delay and turn-off effect) of VCSELs. The simulated results exhibit good agreements with references.

Abstract: Grain size refinement by using equal channel angular Extrusion (ECAE) is an effective way to improve workability and strength of the magnesium alloys. Round workpieces of ECAE processes for AZ31 magnesium alloy are investigated by using numerical simulations and experimental studies in this paper. The processing of ECAE is simulated in order to study the influence of the processing on the deformation behavior of the workpiece and extruding load. The variation trends of the effective strain distributions in the workpiece are changed little for different cross-section. Punch load for extrusion is the major factor to be considered while designing a sound ECAE die. The deformation mechanism of ECAE for grain refinement is obtained. In addition, the experimental finally workpieces shapes and extruding load results are also consistent with FE analysis results.

Abstract: Metal-supported solid oxide fuel cell (SOFC) has a varieties of potential advantages compared to the traditional ceramic supported SOFC. However, degradation issue of metal-supported SOFC is seriously impeding its further development, in particular, the inter-diffusion and interaction of iron, chromium and nickel at substrate/anode interface is known to be a key issue responsible for cell rapid degradation. With respect to the complexity and nonlinearity of degradation mechanism, multi-scale modeling and simulation is regarded as one powerful method to gain a deep insight on degradation mechanism. In present work, multi-scale models were presented to investigate multi-scale physicochemical phenomena happening at interface of anode/substrate, with the attempt to reveal degradation mechanism. The research procedure for the above goal was addressed in detail as well.

Abstract: In this paper, we investigate a delayed three-species food chain model. The existence and stability of equilibria are obtained. A explicit algorithm for determining the direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions are derived by using the normal form and the center manifold theory.

Abstract: In the paper a new method is presented to simulate the course of light output from organic light emitting device. The method uses optical transmission matrix to deal with multiple layers. To confirm the validity of our theories, a comparison of the theoretic analysis with testing results is given. The calculated curve consistented with the experimental value. By this methoed the Commission Internationale de L'Eclairage （CIE） coordinates of device were simulated. By adjusting the thickness of each layer in organic light emission diode (OLED) we obtained different CIE coordinates. When thickness becomes thicker the CIEX becomes bigger on the other hand CIEY become smaller.

Abstract: Erosive burning usually refers to the increase in the propellant burning rate caused by high velocity combustion gasses flowing over the propellant surface. It may seriously affect the performance of solid-propellant rocket motors [1]. A series of experiments had been made to study the effects of length to the diameter ratio in a single tubular propellant grain on the erosive burning phenomenon. In the same combustion pressure and different grain geometries, the burning pattern of AP¹based propellant were recorded. Furthermore, pressure-time curve for each condition was obtained. The mean velocity gradient is obtained by some thermo-gas-dynamical analysis on experimental data. The results can be used for preliminary design of AP based tubular propellant rocket motors. This method may be used for other types of tubular solid propellants which defer in chemical formulation.

Abstract: To introduce a novel method of driving robot move. This method is to use the force-line model to drive the limbs of the robot inspired from the skeleton movement driven by muscle. A humanoid robot with the force-line model has been constructed. New software for muscle force estimation has been developed. The solution of the parameters which are the input of the software has been statement. Finally, the input parameters have been obtained by experiment and calculation. The humanoid robot can be driven to imitate human walking by the force which along the force-line. It will provide wide insight in developing new type robot for complex motion and applying the technology of force-line driving model in other filed.