Advanced Materials Research Vols. 418-420

Abstract: Most narrow-gauge vehicles driven by DC motor now, as DC drive due to power constraints and high maintenance costs, most of them will gradually be replaced by AC drives. But VVVF(Variable Voltage Variable Frequency) control method adopt in some running narrow-track traction locomotives, that can reduce over-current with load starting and should be compensated at low frequency. Based on study the Control strategies of narrow-track locomotives, comparing with the characteristics of power distribution of dual-motor drive system. The motor ought to have the same mechanical feature in dual-motor drive system, vector control strategy select in the control system. Experiments prove the system has good performance of stability, reliability, and good control performance, which can meet the narrow-track traction locomotive control requirements.

Abstract: All the construction methods of subway stations are firstly reviewed in the world, which are cut and cover method, mine tunneling method, tunnel boring machine method and combination methods of them. Finally characteristics of various construction methods are analyzed in detail.

Abstract: Study of the electrochmeical biosensor has become a new interdisciplinary frontier between biological detection and material science due to their excellent prospects for interfacing biological recognition events with electronic signal transduction. Nanomaterials provided a significant platform for designing a new generation of bioelectronic devices exhibiting novel functions due to their high surface-to-volume ratio, good stability, small dimension effect, good compatibility and strong adsorption ability. In this paper, we review the development of electrochemical biosensors fabricated with various nanoscale materials, also highlight the analytical applications in terms of biochemistry.

Abstract: Based on the analysis of the structure, function and transmission ways of polar coordinates wafer-handling robot, the radial liner stretching kinematics model of wafer-handling robot is established, and the kinematics character of the robot is analyzed, the kinematics equations of the robot is established. Finally, based on Microsoft Visual Studio 2008 and Pro/toolkit, the dynamic simulation of polar coordinates wafer-handling robot is realized.

Abstract: Based on the principle of magnetic flux leakage, this paper researches and develops the steel cord belt online testing real-time monitoring system. It take magnetizing and receiving sensor in integrated intensive arrangement, adopt mining intrinsic safe single box-type structure, the temperature is adaptive, free maintenance and avoid debugging. The master control board has two kinds of media communication interface; the transmission distance can be 20km. This system has self-check, parameter setting, data analysis and inquires, report printing, and other functions. Field application show that the system realized high speed, online testing and accurate positioning in steel cord rusting in belt, rope breaking, joint twitch, shifting, zinc coating aging etc. conditions, the judge accuracy rate is more than 99.9 percent.

Abstract: Stiffness and damping of hydrostatic guideways are calculated by small perturbation method based on Reynolds equation in dynamic regime. The hydrostatic guideway is considered as a system which consists of the mass, the spring and the damper. The effects of some main parameters on stiffness, damping and damping ratio are analyzed which include the supply pressure, the film thickness, the pad dimension, the pressure ratio, the lubricating oil volume and the lubricating oil viscosity. The relationships between the settling time of the hydrostatic guideways and these parameters are investigated under a step load. It is shown that the slide block returns to equilibrium without overshooting under a step load, and the amplitude of the block vibration has not a maximum value under a cyclic load, due to the large damping effect( ξ>1). In addition, the settling time can be shorten with the increase of the supply pressure, the film thickness and the lubricating oil volume, and also with the decrease of the pressure ratio and the lubricating oil viscosity. The settling time get the shortest value when recess parameter( α) is 0.55.

Abstract: A body fitted based finite volume method (FVM) model of aluminum extrusion processes was established in this paper. The basic theories and rigid-plastic flow theories of this model were researched and built. Body fitted grids were used to match complex geometric boundaries and local refinement of grids was also realized. Plastic shear friction model was applied on body fitted grids. A typical then walled profile extrusion process was simulated using the program developed in this paper. The simulation results were also compared with that simulated by FEM software Deform in the same process, material and die conditions. The feasibility and efficiency of the mathematic model built in this paper was demonstrated by the simulation results and the comparison.

Abstract: Lagrange-Maxwell equations and Park transform are adopted based on electrical and mechanical energy equations consisting of servomotor parameters. Lagrange-Maxwell equations are transformed from three-phase stator reference coordinates to two-phase rotor reference coordinates. Electromechanical coupling dynamics equations of permanent magnet synchronous servomotor in two-phase reference coordinates are obtained. In this dynamical modeling method of electromechanical coupling system, to establish dynamical differential equations needs to measure amplitude of the flux induced by the permanent magnets and the winding's inductance in dq0 reference of the motor but needs not to measure the size of magnetic circuit. The equations deduced is terse, efficient, and the equations easy to use. Electromechanical coupling dynamics system, servomotor is simulated. Simulation results show that the electromechanical coupling dynamics equations deduced for servomotor are correct, and current control schemes are reasonable.

Abstract: With the unique function of simulating a combined environment of high static fields and shaking load, centrifugal shakers can provide an effective and advanced testing method to dynamic characteristics and failure mechanism of reduced scale structure models and materials. Their construction has begun both at home and abroad, whereas waveform distortion and instability often happen to the perfect shakers after installed on a centrifuge in the process of their construction. The knowledge about this phenomenon is difficult to find and systems theory is absolutely blank. Practically the construction of centrifugal shakers is still in an exploratory stage. This paper analyses coupling control of shakers on a centrifuge in three aspects of installation method, bucket deformation and arm deformation. Simultaneously corresponding analytical models is also established, aim to guide theory study and equipment design.

Abstract: A new annual runoff prediction model was proposed by combining the least squares support vector machines and markov chains named LSSVM-MC. Firstly, adopt the least squares support vector machines to predict annual runoff as the first step prediction. Then regarding the series of prediction errors as a process of Markov chain, adopt Markov chain method to predict the potential error as the second step prediction. At last, subtract the two-step prediction results to get the final prediction value. The case study shows that the combined model effectively improves the annual runoff prediction accuracy.