Advanced Materials Research Vols. 712-715

Abstract: In the process of gear grinding, the grinding worm profile was modified with the wear of grinding worm, which has an important influence on machining accuracy. In this paper, the profile of grinding worm was calculated and simulated according to the tooth contact analysis. The profile error was analyzed according to the outer diameter of grinding worm. With the wear of grinding worm from outer diameter 400mm to 380mm, the grinding worm profile was recalculated after being redressed to ensure grinding accuracy.

Abstract: In order to make the substituted circular arc generating lines be a series easily, based on the principles of cutting hypoid gears by generating-line method and the pinion generating lines substituting method, an optimization which the objective was to make the substituted circular arc generating lines radiuses of pinion be integers or approximate integers was proposed. The feasibility of this optimization method was verified by the calculating example of a pair of hypoid gears.

Abstract: Against defects of three-roll fixed axis rolling mill caused by rolled piece rotating in process of rolling, presented three-roll planetary rolling scheme, designed the planetary transmission system structure, expounded planetary mill rolling process, analyzed movement relationship between planet carrier, roll and rolled piece according to planetary gear train transmission principle. The rolls do planetary motion and spinning motion both, the former acts on the rolled piece to make it do clockwise rotation movement, the latter acts on the rolled piece to make it do anti-clockwise rotation. The actual movement of rolled piece is combination of the two motions. The theoretical analysis and calculation shows that in rolling process of planetary mill, the speeds of above two kinds of motions are very close, directions are opposite. Due to rolls are inclined compare to the rolled piece, as a result rolled piece does axial movement with a speed of vsinα, radial rotation speed is 0.0029 times of planet carrier rotational speed. Thanks to complexity of extrusion and friction between rolls and rolled piece, the actual speed of rolled piece is approximately zero. Prototype rolling test has verified correctness of theoretical analysis and calculation.

Abstract: For solving the continuous and integer variable optimization problems in gear transmission, this article to establish a gear transmission optimization mathematical model, study the influence of modulus, tooth width, helix angle and tooth number on objective function by genetic algorithm, and the digit results is well.

Abstract: On the basis of the carrier has a low frequency in underwater electric current communication, carrier phase shift network, low frequency wide band phase shift network and multiplier circuit were designed to realize the single side-band (SSB) modulation. The circuits were designed and debugged. Through testing the actual circuits, sideband suppression ratio obtains 36dB which can satisfy the underwater electric current communication system. It will be stated reference on actual application for SSB modulation with low carrier frequency using phase shift method.

Abstract: Based on the special correlation of antennas and the power delay profile (PDP) of the cluster model, six models of A-F have been established by the TGn task-group in total. On the basis of the new broadband wireless local area network (WLAN) standard--IEEE 802.11ac with larger bandwidth and multi-user requirements drawn up by the TGac task-group, in this paper, the IEEE 802.11ac channel model is set up by means of improving and simulating the indoor MIMO channel.

Abstract: Now Z-Source inverter is replacing traditional inverter and becoming a research focus. But traditional Z-source inverters bring high voltage stress both in DC input and the Z-source network, which restricts its wide application. In order to solve this problem, a new type Z-source structure with third harmonic injection control strategy is proposed in this paper. The principle and operation models are analyzed. Compared with traditional boost-type Z-Source topologies, the proposed topology offers lower voltage stress, whats more, soft-start strategy can be implemented to suppress the inrush surge arising in the start process. Finally, simulation results demonstrate the good performance of the proposed inverter.

Abstract: A new type of the two dimensional photonic filter which includes two in-line waveguides and a circular ring resonant cavity is presented in this paper. By using Finite Difference Time Domain (FDTD) method, we calculated and demonstrated the broadband frequency response of the filter and analyzed the impact of changing the dielectric constant of the inner rods on the transmission characteristics of the filter. Compared with the transmission characteristics of a micro-cavity,our numerical results show that such a filter can transmit multiple narrowband signals simultaneously. The number of the passbands of the filter increases with the rings of inner dielectric rods in the cavity. The center wavelength of the passbands can be tuned by adjusting the dielectric constant of the whole rods and inner rods without changing the size of the cavity..

Abstract: Design of a digitally tunable tracking preselected filter for improving anti-interference for Ultra Short Wave receiver front-end is proposed in this paper and the characteristics of the preselected filter circuit are analyzed. Then we mainly discuss an inductor-coupled dual resonant structure with better selectivity and anti-jamming and its implementation. Finally, test results are provided, shown the specifications of the circuit are in great agreement with the simulation and design requirements.

Abstract: The elementary structure and operation principle of the VSC are introduced. Detailed analysis of the PWM control principle and the steady-state mathematical model. And a steady-state controller design scheme based on the PID control principle is also proposed. The simulation results show that the method have good control ability, quick response to breakdown and good stability.