Applied Mechanics and Materials Vols. 602-605

Abstract: The paper first introduced the magnetic coupling resonance wireless power transfer system principle, the coupling model theory, etc. Through matab program, the paper could get advice system parameters according to the specific load, the needed transmission distance and transmit power of the system. These parameters give guidance to the system design, which is verified through examples.

Abstract: According to analyzing the basic principle of intrinsically safe output quasi-Z-source Boost Converter, this topology can be modeled. When the quasi-Z-source network parameters L_z and C_z are much smaller than conventional converter parameter LC, transfer function can be order-reduced. Design the close-loop controller after the simplified transfer function model. Finally use the traditional cut-off output protection circuit to verify the theoretical analysis.

Abstract: With the further promotion of electric enterprise information construction, industrialization and informationization have been deeply integrated. Power system safety and stability is highly dependent upon electric information system. However, as the electric business higher integrated, data more interactive, and structures more complex, electric information system would face serious security risks. Any simple system may become the "short board" of enterprise information security protection architecture, and any vulnerability may bring serious consequences. In this paper, we propose an information security framework for electric system lifecycle based on typical information security model. As the framework widely applied, the overall safety capacity of electric enterprise has increased substantially.

Abstract: For a long period, the sky-wave over-the-horizon radar (OTHR) has difficulty in detecting ship under the background of sea clutter, and it is difficult to apply the existing sea clutter model established in surface wave propagation mode to the sky-wave OTHR sea clutter suppression. Therefore, the difference between surface wave and sky wave propagation mode is analyzed firstly, then the scope of grazing angle about sky wave beam is calculated, finally the backscattering coefficients of sky wave from sea surface are derived by perturbation method and the backscattering mechanisms of sky wave from sea surface are analyzed. Results show that the mechanisms observe Bragg scattering mechanism. The backscattering coefficients of sky wave from sea surface which are given in this paper for the first time are significant for sky-wave OTHR sea clutter suppression.

Abstract: LED has been regarded as the next generation lighting source. As for high power LED lamps, heat accumulation will cause a series of problems. Therefore, thermal management is very important for designing a high power LED lamp. Three types of heat sinks are designed by using the finite element analysis (FEA) method for an 180W high power LED lamp. Then the optimized heat sinks are developed and experiments are performed to demonstrate the simulated results. At the same time, the thermal performances with different working angles are investigated experimentally. The heat sink with heat pipe has a better heat dissipation performance than the conventional heat sink under the same input power. The working angles of the lamps greatly influence the thermal performance of each heat sink. For the same heat sink, the temperature varies with different install directions and working angles. Finally, the heat sink with the best thermal performance is recommended. The results have practical significance in designing high power LED lamps.

Abstract: We investigate the output characteristics of Smith-Purcell free electron laser based on an all-feedback resonator by theoretic analysis and particle-in-cell simulation method. The simulation results show that the output power spectrum density is different with different azimuthal angle range in this device. The output power spectrum density on azimuthal angle curve is a nonlinear curve. This output characteristics is important to design the port of this device.

Abstract: There are different magnetic property of materials mixed in the mechanical wear of abrasive and powder processing. Depending on different alloy and magnetized material with different magnetic saturation characteristics, some substances reach the magnetic saturation in the magnetization processing soon, while some substances must be in a strong magnetic field to reach saturation, resulting in the magnetic property of combination material mixed with multi-component metal abrasive has multi-ingredient combination characteristics. Based on the PQ excitation measurement method, we analyze the magnetic property between the typical magnetic abrasive individual and combinations. We also build the magnetic spectral characteristics of the mixture which is made up of materials with different magnetic property, and finish the establishment of two mixtures mapping. This paper aims to explore the magnetic spectral analysis method of ferromagnetic mixture from the theory and experiment, and propose the magnetic spectrum analysis and calculation method of the mixture.

Abstract: Surface plasmonic waveguides usually only support one mode called TM (transverse magnetic) mode. Recently, one waveguide structure that can propagate both TE (transverse electric) and TM mode was proposed. However, the large propagation loss of the plasmonic waveguides with low polarization dependence is still a problem. In order to make loss compensation to solve the problem, this paper makes improvements to decrease the loss of this kind of waveguide. Simulations have been made to prove the feasibility; as respected, low loss or even 0dB can be reached at both modes when low and high index materials are added. The improved plasmonic waveguide has a potential application in guiding and processing of light from a fiber with a random polarization state in low-loss condition and also can be applied to integrated optics devices.

Abstract: Using a two-dimensional ensemble Monte Carlo (EMC) method, the noise spectrum of a InGaAs-based nanoFET is studied in detail. Simulation results show that the noise spectrum consists of two maxima at frequencies of about 0.7 THz and 2 THz. The lower-frequency maximum is sensitive to the source-drain voltage, while that of the higher frequency one is not. These achievements are coincident with experimental results. Moreover, based on Dyakonv-Shur’s theory, the emergence of noise maxima is explained as the excitation of 2D plasma waves in the device.

Abstract: In order to collect and process data effectively, express the advantage of LabVIEW, this paper presents a design method for collecting and processing data in more channel using PXI-5922 and PXI-6733 based on LabVIEW. The system can realize two channel signals generation, data collection and signal analysis.