Advanced Materials Research Vols. 998-999

Abstract: The flow field of a cruciform finned guided projectile with and without fin slot was simulated by the mean of CFD(computational fluid dynamic) numerical method. The characteristics of pressure field distribution without and different widths slots were calculated and compared. The influence of fin slot to the aerodynamic characteristics such as drag, lift, roll moment, pitch moment static aerodynamic characteristics as well as pitch, roll damping moment dynamic aerodynamic characteristics were emphasized in different angle of attack. The numerical results were certified by the good agreement between the wind tunnel test results. Important reference was provided to theoretical research and engineering for guided projectile shape design.

Abstract: In order to guarantee the safe and efficient production of coal mine of Huoerxinhe Company, for the problems of gas exceeding limitation, excavating replacement tension, resource waste air leaking and so on, the ventilation mode was optimized and Y type ventilation mode was adopted. Practices indicate that this ventilation mode is entirely feasible on working face of Huoerxinhe Company. Through this mode, we can (1) decrease the tunneling engineering quantity, improve the excavating replacement tension of double U type mode; (2) reduce the protective coal pillars to cut down resource waste; (3) solve the problem of gas exceeding limitation on upper corner thoroughly.

Abstract: Paper presents a practical circuit topology and analyzes the converter working process. The converter leading pipe is used MOSFET to achieve a zero voltage turn-on and turn-off, and lagging using is used IGBT to achieve a zero current turn-on and turn-off. After the topology circuit parameters selected by the relevant waveform acquisition, the converter design is verified correct. By running on the power supply operation, converter excellent performance meets the market requirements.

Abstract: This paper realized the 3-dimension model for helical intake port and simulated the different kinds of position deviations by the application of reverse engineering. The three-dimensional flow field in port-cylinder was numerically simulated by the use of CFD software FIRE to verify how the position deviations affect the performance of the helical intake port. The result shows that the slanting and translational position deviations have the marked effect on the swirl ratio of the helical intake port and the strict control of production precision is needed.

Abstract: The method of day-ahead dynamic economic dispatch is applied to the micro-grid composed of photovoltaic (PV) generation system and batteries to make its operational cost minimized. The battery life was converted cost and added to the objective function. Micro-grid’s mathematical model of economic dispatch was set up. Mathematical model of economic dispatch was solved by using the method of real population genetic algorithm. The charge and discharge plan of battery in micro-grid and buying or selling electricity plan between micro-grid and State Grid was established at the same time. Taking real data of Shanghai Electric Group’s micro-grid for case study, the dynamic economic dispatch is compared with traditional dispatch strategy. The results verify the effectiveness of the dynamic economic.

Abstract: This paper starts from the micro-film platform-new media and explores features of the micro-film by analyzing the characteristics. It takes this point as the center of the paper, combining the integration of the tri-networks as well as the status of the new and old media. Finally the author raises some strategies for the development of marketing mode for the micro-film.

Abstract: According to the development requirements of CAD/CAM numerical control processing simulation software, now take the simulation of milling whorl processing as an example. Based on AutoCAD application platform, and the theory of whorl milling processing, LISP is used for programming, and the simplified ball three-dimensional entity model of the disc cutter is shown. Through object boolean operation, the milling simulation program is called, finally realizing the dynamic 3D simulation of whorl milling processing, providing technical support for the real-time observation of numerical control milling.

Abstract: An intelligent rolling bearing fault diagnosis method is proposed using empirical mode decomposition (EMD)–Teager energy operator (TEO) and Mahalanobis distance. EMD can adaptively decompose vibration signals into a series of intrinsic mode functions (IMFs), which are zero mean monocomponent AM–FM signals. TEO can estimate the total mechanical energy required to generate signals. Thus, TEO exhibits good time resolution and self-adaptive ability with regard to the transient components of the signal, which is an advantage in detecting signal impact characteristics. With regard to the impulse feature of the bearing fault vibration signals, TEO can be used to detect the cyclical impulse characteristic caused by bearing failure, gain an instantaneous amplitude spectrum for each IMF component, and then identify the characteristic frequency of a single, interesting IMF component in the bearing fault by means of the Teager energy spectrum. The amplitude of the Teager energy spectrum in the inner race and outer race fault frequencies, as well as the ratio of the energy of the resonance frequency band to the total energy, were extracted as feature vectors, which were then separately used as training samples and test samples for fault diagnosis. Thereafter, the Mahalanobis distances between the real measure and the different overall types of fault samples were calculated to classify the real condition of the rolling bearing. Finally, the Mahalanobis distances were converted into CV values, which assessed the current health state of the rolling bearing. Experimental results prove that this method can accurately identify and diagnose different fault types of rolling bearings.

Abstract: Power amplifier is an important part of maglev control system and it may need lots of time and manpower at regulating PI parameters. To solve this problem, an equivalent model was proposed to simplify the parameter adjustment. In this paper, firstly, mathematical model of the power amplifier was proposed and the Simulink model was built in Matlab software. Then the experimental platform was established and dynamic properties of the power amplifier were studied by simulation and experiment. The results show that the overshoot and rise time of experiment and simulation results matches well and the error of cut-off frequency is less than 10%. Therefore, it has instructional significance for parameters design.

Abstract: In order to obtain higher levels of surface form accuracy, it adopted rotational averaging method, analyzed the supporting position and rotation-angle deviation of the model via the finite element analysis technology. You can see that the mirror surface Peak Valley Value and Root Mean Square Value, increase with the increase of supporting and angle deviation. Thus, to realize high precision mirror surface detection, it should guarantee the supporting position and rotation-angle deviation of the model at the same time. The measurement precision of rotational averaging method absolute measurement can achieve one percent wavelength (λ=632.8nm),it is far superior to the other detection technology in absolute measurement.