Advanced Materials Research Vols. 466-467

Abstract: Shaft guide is detected mainly by a static test method ,but it need much time to detect and practical experience of the technical person for most of the mine. This paper designs a testing system based on matlab to solve this problem and introduces the system’s survey principle. The dynamic parameters of shaft is measured by tilt sensors, acceleration transducer and displacement sensor separately, the relations between the shaft rigid’s parameters and breakdown is analysed. The selection and design of hardware system is rational as well as software’s function, the system has strong practicability.

Abstract: In order to investigate the drag characteristics of high speed projectile in the states of supercavitation shape, this article presents the shape design’s method and gist of the underwater high-speed projectile. The first, the shape model is presented that is based on the potential panel method to the slender axisymmetric body. The second, the effect is analyzed comparatively that is from the difference shape to the supercavitation. The simulation results show that smaller drag coefficient of the projectile can be obtained by increasing the slenderness ratio and the barycenter position.

Abstract: This paper pointed out the importance of safety prediction, introduced system dynamics into coal mine safety prediction, analyzed main controllable safety factors in coalmine and causality diagram, established the system dynamics flow chart model and used the method of simulation data to demonstrate the theoretical effectiveness which provided a reference for safety managers to make decision.

Abstract: Product image retrieval using content of the image is valuable for E-commerce application. But both search efficiency and accuracy are challenging the implementation of content-based image retrieval in large product image database. We present a two-stage product image retrieval method, with fully consideration of individual features of product images. In the initial pruning stage, shape feature based on salient edges of product object is used to generate a moderate number of candidates; in the second stage, the proposed detail feature combined with color and texture features is used for fully retrieval. Experiments show that this two-stage retrieval method accelerates search process with a high accuracy.

Abstract: This paper first introduces the recent development of the popular hysteroscopy, the international minimally invasive diagnosis instrument, and then analyzes the lighting and video of hysteroscopy. According to high energy consumption of common hysteroscopy, front located hysteroscopy system is put forward. The principles, the lens structure, the manufacture process of lens prototype, the trial manufacturing process of power box are all discussed in this paper. It is the first time that prototype has been design and tested in domestic. In the normal conditions, the energy consumption decreased by 299/300. And the volume, the weight, and the price of the designed front located hysteroscopy are greatly reduced. Moreover, tests show that it can apply to special conditions such as the disaster relief field and field operation.

Abstract: National University of Defense Technology has begun a research program to investigate and test ducted-fan propeller architecture for UAV designing. Development of a prototype continues to support ongoing research in the area of autonomous systems. In this paper, we build a nonlinear dynamic model of Ducted-Fan UAV for verifying appropriate controller behavior, and design a hierarchical controller for hovering flight of the UAV.

Abstract: Design proposal of reconfigurable shift unit based on multilevel interconnect barrel shifter is presented, which can support 8~32 bit wide and any variable length between 1 bit and 31 bit. Through adding expander circuit, the width of this unit can broaden to 8~128bit. The design has been realized using Altera’s FPGA and synthetized and optimized on Synopsys’s Design Compiler. The result proves that the maximum frequency can achieve 400MHz on 0.13µm CMOS technology.

Abstract: To get a better understanding of tracking capability and accuracy of the equipments onboard space tracking ships, it is necessary to perform precision evaluation. In order to achieve satisfactory results, dynamic flight experiment is organized, during which a series of new methods and technologies are applied, with GPS carrier wave phase difference technology as the center, among which GPS data processing technology is empathized. Based on above, a set of complete GPS data processing models for precision evaluation are established

Abstract: A new Electromagnetic Heating System for riveting is designed bascd on the electromagnetic heating theory which centers on TMS320LF2407. The design philosophy, working principle, the hardware and software of system arc presented. Moreover, the basis of design and parameters of application arc introduced in details. The application shows that the system is rcliable, efficient and convenient.

Abstract: Photovoltaic (PV) grid-connected system requires the inverter possesses excellent dynamic and static characteristics. In the view of the mathematical model of the inverter is nonlinear, we will adopt a kind of nonlinear control strategy called Passivity–Based Control (PBC). First we establish the standard Euler – Lagrange (EL) mode for inverter, then we also prove that this inverter is strictly passive. Based on passivity of inverter, we can redistribute the system energy, and adopt the approaches of injecting damping and decoupling to improve system performance. In this paper, we can control the active and reactive power of system to make system can fast track the PV array maximum power point, and possess the capacity of compensating the reactive power. Simulation results show that passivity-based control method can make the inverter possess better robustness and dynamic.