Advanced Materials Research Vols. 181-182

Abstract: Monodisperse nanowires of rare earth phosphates were synthesized by chemical precipitation method using anodic aluminum oxide (AAO) template. Scanning electron microscope (SEM) images indicated that rare earth phosphate nanowires are parallelly arranged in AAO template, all of which are in uniform diameter of about 50 nm. X-ray diffraction (XRD) patterns and high magnification transmission electron microscopy (HRTEM) images showed that the nanowires were polycrystal structure.

Abstract: The long term oxidation test of FeCrAl substrate treated by ultrasonic and electroplating methods was performed at 9000C in air environment for 100 hours. The purpose of this paper is to show the nickel layer evolution of that substrate. Oxide scale and layer evolution were assessed on specimens using scanning electron microscope (SEM) coupled with energy dispersive X-ray spectroscopy (EDX). The nickel layer disappeared and fully converted to be nickel oxide on FeCrAl treated using ultrasonic and nickel electroplating after oxidation exposure at 9000 C in air for 100 hours. In this condition, the nickel oxide still existed. Not only nickel oxide and Al2O3 were occurred when oxidation exposure at this condition but also Cr2O3 and Fe2O3. The lowest parabolic rate constant was obtained from FeCrAl ultrasonic treatment with SiC for 50 minutes at 1.21 x 10-4 mg2mm4h-1, and FeCrAl ultrasonic treatment with Al2O3 for 30 minutes at 1.15 x 10-4 mg2mm4h-1. The lower parabolic rate constant indicated the higher long time to failure of the FeCrAl substrate.

Abstract: In the actual course of commercial operations, governance mode is mainly divided into two categories: alliance mode, leading by real estate developer, and integrated mode, leading by commercial operators. The transaction efficiency and cost vary corresponding to the different mode. In this paper, based on the traditional market, hybrid and hierarchical mode framework in transaction cost theory, inframarginal theory and the actual Chinese commercial management, the author discusses the existing conditions of market, hybrid and hierarchical mode, verifies that the complete market mode in the actual operation process does not exist, at the same time, deeply analyses boundary conditions for the existence and basis for decision making of the alliance mode and integration mode.

Abstract: A new type of hybrid cubic manipulator with six degree of freedom(DOF) suggested based on traditional serial manipulator and parallel manipulator, three dimensional translation and rotation of output shaft obtained through lineal driving. Define the description of spacial moving capability of common couples and translation base and rotation base of mechanism, based on the fact of mechanism consists of components, a new description method by topological graph theory of components relationship suggested, new description of serial mechanism and parallel mechanism and hybrid mechanism obtained with this method, description elements include component pane and constrained component pane and component relationship line and constrained component relationship line and spacial relative moving capability between adjacent components. DOF(degree of freedom) of hybrid mechanism analysised with example based on the definition of dimensionity of branch spacial moving capability and mechanism spacial moving capability, necessary and sufficient condition of nonsingularity of mechanism presented. Method of analytic geometry used to find the regular cuboid of the reachable working space shape of mechanism, the volume of the reachable working space rest with the limit of translation of couplers, its influential factors obtained, still the rotational angle limits of output shaft at given configuration analysised through the method of drawing, and limit length of guideway etc. are the primary influential factors.

Abstract: Design of magnetic circuit is the key for disk MRF brake and has an important effect on brake torque per unit mass. In this paper structure and working principle of disk MRF brake are introduced, and magnetic circuit is designed by using engineering magnetic field method, and main technologies are introduced in detail, and its magnetic field is analyzed based on finite element method. This is benefit for structure optimization of the magnetic circuit. The feather of the magnetic circuit is received by numerical analysis method, and magnetic saturation and leakage phenomenon are found at the circuit, and these problems should be paid attention especially.

Abstract: The aim of this paper is to study mobile geographic information system (mobile-GIS) technology to design an asking for direction multimedia system, by applying ArcGIS Engine developer kit, Database Management System (DBMS) and Winsock mechanism in Microsoft Visual Basic 6.0 computer programming environment, to help mobile telephone users find right target location in short time in secondary development. Databases store various types of geographic data with location information. The prototype system developed implements the function of asking for direction. After the Multimedia Message Service (MMS) request is sent, the multimedia message in picture format with detailed map information through wireless network will be received, which can be displayed on mobile telephones. According to the map instruction, mobile users can find the correct destination and a lot of time can also be saved. The result shows that the prototype system runs relatively stable. As a kind of value-added service of China mobile, the prototype system is worthy to popularize.

Abstract: The effect of curing pressure, curing temperature and curing time on the mechanical properties of the adhesively bonded composite structure of CFRP and Al are studied by means of the Orthogonal Test. Indexed by the fatigue life of the composite structure of CFRP and Al in room temperature environment and by making the direct, variance and effect analysis for the test data, we have obtained the optimal curing technology scheme within the test range. Because the optimal scheme isn’t included in the orthogonal table, we make the point estimation in order to get the fatigue life corresponding to this scheme. At last, the fatigue life under the optimal scheme is obtained by adding a test, the result of which is consistent with that of the theoretical analysis.The effect of curing pressure, curing temperature and curing time on the mechanical properties of the adhesively bonded composite structure of CFRP and Al are studied by means of the Orthogonal Test. Indexed by the fatigue life of the composite structure of CFRP and Al in room temperature environment and by making the direct, variance and effect analysis for the test data, we have obtained the optimal curing technology scheme within the test range. Because the optimal scheme isn’t included in the orthogonal table, we make the point estimation in order to get the fatigue life corresponding to this scheme. At last, the fatigue life under the optimal scheme is obtained by adding a test, the result of which is consistent with that of the theoretical analysis.

Abstract: In this paper, we investigate the radial compression and inflation of a spherical shell composed of two compressible hyperelastic materials. We first establish the mathematical model of this problem as a second order nonlinear differential equation with two boundary conditions, and then transform it into a system of first order nonlinear differential equations. By using dimensionless transformation, we obtain the parametrical analytic solution. Finally, the results of the numerical simulation are given. We analyze the influence of the material parameters and the structure parameters on radial deformation of the spherical shell. These results well fit the practical phenomena.

Abstract: The fuzzy clustering algorithm is sensitive to the m value and the degree of membership. Because of the deficiencies of traditional FCM clustering algorithm, we made specific improvement. Through the calculation of the value of m, the amendments of degree of membership to the discussion of issues, effectively compensate for the deficiencies of the traditional algorithm and achieve a relatively good clustering effect. Finally, through the analysis of temperature observation data of the three northeastern province of china in 2000, the reasonableness of the method is verified.

Abstract: PWM inverter, as the main part of wind power grid-connected system, directly determines the quality of the power sent finally to grid. It has become the focus of research to develop a high-performance inverter control system. Based on the analysis and establishment of the mathematical model of the grid inverter system, the vector control strategy based on the voltage directional technique is analyzed in this paper. It consists of two closed loops. The fluctuation of direct voltage is suppressed due to the existence of voltage outer loop. Current inner loop realizes the independent control over meritorious electric current and reactive current through the feedforward of grid voltage and the decoupling of grid-connected current, which makes the inverter power factor close to 1.