Applied Mechanics and Materials Vols. 143-144

Abstract: This article describes a solution of the Profibus-DP bus system of intelligent circuit breaker based on introduction of Profibus fieldbus. The design of hardware and software of intelligent slave station interface based on intelligent communication chip SPC3 was intrduced in detail, at the same time, master and slave station are combined adjusting. The experimental results proved that the system could be worked properly.

Abstract: In the power electronic circuits, AC chopping control voltage regulation circuit through change the chopped device conduction time, it can easily change output voltage size. Load currents do not include low-order harmonic, they contain only higher harmonic which are relevant to the switch period , they are easy to filter out. So the power efficiency is high and it is characterized of high performance. This paper introduces a kind of widely used AC chopping control voltage regulation circuit and we simulate it by simulink. The result fully embodies the superiority of this kind of circuit.

Abstract: The grid-connected photovoltaic system is a trend of photovoltaic system development. According to the character of solar array,we designed a novel grid-connected photovoltaic inverter with the function of Maximum Power Point Tracking.The inverter consist s of a DC-DC converter and a DC-AC inverter and the two parts are combined by a Dclink. The part of control achieve synchronization sinusoidal current output with the network voltage.

Abstract: This paper focused on a novel three-level SVPWM algorithm. Traditional three-level SVPWM algorithm is very complex and it can’t be used in multi-level SVPWM easily. The algorithm proposed in this paper is easy to realize based on that of two-level SVPWM algorithm. Based on this algorithm, voltage reconstruction algorithm for three-level converter is first proposed in this paper. All algorithms can reach good performances according to simulation and experiment results.

Abstract: The field angle of TMA (three mirrors aberration) optical system is larger than coaxial optical system and more susceptible to the structure deformation. Thermal optical analysis is proposed for evaluating the optical MTF (module transform function). Temperature loads, such as X axial, Y axial and Z axial temperature gradients, are put on the optical system. The thermal elasticity deformations of reflector mirror surfaces made by frame deformation are computed. The deformations of reflector mirror surfaces are expressed in Zernike polynomial. With the optical design software optical MTF is computed. The results show that the X axial temperature gradient causes the MTF of optical system reduced furthest, the Y axial temperature gradient causes the minor MTF change, and the Z axial temperature gradient causes the least change of MTF. The research jobs could give some guidance and reference for the thermal design for TMA optical system.

Abstract: Aiming at how to detect evaporation duct environment accurately in real time, method of detecting atmospheric duct by using laser technique was put forward. From the model of air refractive index of radar band, theoretical relationship between laser scattering properties of aerosol over the ocean and vertical change characteristics of the air humidity was established; judge whether to produce evaporation duct, through using laser to detect the echo signal characteristics of aerosol. The research content is an important complement for methods of atmospheric duct detection, and it can solve several common problems that atmospheric duct forecasting methods needs rigorous measuring conditions, its measurement results delay, it need be estimated by experience and detecting precision is not high, which has higher military application value.

Abstract: Zn1_-xCo_xO nano powders have been successfully prepared by ball milling and have been annealing at 600°C. The crystal structure and optical properties of sample were characterized by X-ray diffraction (XRD), photoluminescence spectra (PL) and ultraviolet visible light absorption spectra (UV), and the formation mechanism was discussed. Co-doped ZnO nano powders exhibit wurtzite (hexagonal) structure. Co²⁺ enters into ZnO crystal structure and substitutes for Zn²⁺. All samples show typical luminescence behavior with about 396nm UV emission peak. In addition, the about 450nm and 470nm blue emission peaks are found in photoluminescence spectra. Before the doped content is within 8at%, the band edge of ultraviolet absorption appears red shift phenomenon with the increase of doping content. The peak position was shifted from 362nm (3.43eV) to 367nm (3.38eV). Annealing is in favor of the replacement that Co²⁺ enters into ZnO crystal structure and substitutes for Zn²⁺

Abstract: The study proposes a robust method to extract the line structured light stripes in industrial environments. The line structured light stripe is projected onto the laser weld seam to be measured by a projector, and deformation of the stripe is detected by a CCD camera with industrial microscope lens. An image processing method that can efficiently locate the deformation of the stripe in the image plane is presented. Finally, the method is applied to two kinds of laser weld seam specimen applications, and excellent performance is shown by some experimental results.

Abstract: Transparent conductive ZnGa₂O₄ thin films were prepared by magnetron sputtering. The chemical state of O, Zn and Ga in the deposited films was investigated by X-ray photoelectron spectroscopy (XPS), and the optical properties were characterized by optical transmittance spectra. The XPS studies reveal that no metallic Zn and Ga were detected in the ZnGa₂O₄ thin films, and Zn and Ga exist only in oxidized state. The optical bandgap was calculated by Tauc's theory and the optical constants were determined using Swanepoel's method. Furthermore, the dispersion behavior of the refractive index was studied by means of single-oscillator model, and the physical parameters and the refractive index dispersion parameter were obtained. The results provide some useful references for the potential application of the ZnGa₂O₄ thin films in optoelectronic devices.

Abstract: The concept of vectorial nonparaxial cosh-squared-Gaussian (ChsG) beams is introduced and their free space propagation equations are derived analytically by using the vectorial Rayleigh-Sommerfeld diffraction integrals, and far-field expressions as well as paraxial propagation formula are obtained in free space. Numerical calculations and analysis show that, the f-parameter and decentered parameter plays an important role in determining the far-field properties of the vectorial nonparaxial ChsG beams.