Advanced Materials Research Vols. 383-390

Abstract: Based on the platform of laser-triggered surface flashover in pulsed voltage, experiment of laser-triggered surface flashover switch is carried out in vacuum condition with pulsed voltage. The switch consists of flat electrodes and columned insulator. A single/double harmonic, with wavelength λ of 1064/532 nm, Q-switched Nd: YAG laser is applied to trigger the switch. The results of experiment show that switch delay time and jitter time decrease with increase of pulsed voltage and laser energy density. Based on the waveforms of switch voltage and switch current, the circuit model of laser-trigger flashover switch is set up by circuit method in the paper. The parameters of the circuit model are calculated through the waveforms of the experiment, and the waveforms of switch voltage and switch current are obtain through circuit simulation. The simulation waveforms of the switch model are consistent with the waveforms of the experiment.

Abstract: The electroexplosive devices(EED) are widely used in the core system of rocket, missile and nuclear weapons. Hazard analysis and measurement of electromagnetic pulse is of great importance to the security and reliability of EED. In this article, an optical-fiber fluorescence temperature sensor is proposed for analyzing hazard induced by electromagnetic pulse of EED. The temperature of EED can be measured through the fluorescence lifetime, then the induced current is obtained, and thereby the electromagnetic pulse induced hazard can be draw. The experiments show that, the set-up of this proposal can works with high precision and fast response, and immune to the electromagnetic interference.

Abstract: This paper analyzed the automobile defects and its risk characteristics; the Event Tree Analysis (ETA) method was introduced to determine the risk flow route of automobile defects. According to the scattered of automobile, a risk forecast method based on the Weibull distribution is established. Based on the thousand vehicle breakdown number for risk probability forecast, propose a risk assessment model of automobile defect. The results indicate that on gathering actual failure data from after-sales service, the Weibull distribution model has a favorable applicability for forecasting risk possibility.

Abstract: In this paper, through a series of experiments in steam generator, which located in the simulation platform of nuclear power, the model of the water position of the Nuclear Steam generator is concluded. Comparing with traditional PID control, adoption of fuzzy immune control strategies gets better results. The thesis also verifies the excellent self-adaptive ability the fuzzy immune PID control possesses.

Abstract: Aircraft is more light than usual because of using the material of carbon fiber, which can make aircraft lighter than metal materials. But the shielding effectiveness of carbon fiber is worse than metal materials. First, This paper explains the direct effect and the indirect effect which aircraft suffer of the lightning strike. And then this paper analysis and imitates the carbon fiber cabin struck by lightning. And then, at two circumstance of indirect effect, this paper gives the result of electric field, magnetic field and surface current. Finally, this paper gives some advice for defending outside the carbon fiber cabin and electromagnetic compatibility (EMC) inside the carbon fiber cabin.

Abstract: This paper proposes a novel control approach for single phase active power filter (APF) based on switched system theory, since the switching performance of APF. The switched model of APF is established by means of switching function. On this basis, the switched system error model is obtained. After that, a quadratic Lyapunov function is design to determine the switched control law. The switched control can make the switched system asymptotically stable and compensate the distorted current caused by the nonlinear load current. The effectiveness and rationality of the proposed approach is confirmed by the simulation result compared with the linear voltage control approach.

Abstract: Induced eddy currents in can cause loss when the canned motor runs, the loss make the motor`s temperature rise, directly affect the canned motor pump and the entire transmission system security. Empirical formula estimates eddy current losses which has a big error, it is difficult to meet the engineering requirements. For the canned motor with Hastelloy-C alloy or Sus316L cans, analyzed electromagnetic field and calculated can loss using a finite element method of Ansoft. The paper developed four prototypes, and obtained the experimental value of can loss via simple no-load experiment by the loss separation method. The results are compared with simulation value show that the accuracy of FEM is higher accurately than empirical formula; Analysis shows that dimension of a model and can material characteristic parameters such as the resistivity influence on the calculated error of FEM, the paper proposes to correct the error in the case of considering can material characteristic parameters.

Abstract: The voltage harmonic is an important indicator to evaluate the power quality of PM wind generator. Voltage waveform is closely related to the degree of the air-gap magnetic field waveforms sinusoidal in the motor, so generator structure optimization to improve the degree of air-gap magnetic field sinusoidal is an effective method to improve the quality of generator voltage waveform. This paper presents a method called pole width modulation method to reduce voltage harmonic of wind permanent magnet generator. Do respectively finite element analysis to traditional surface permanent magnet generator and a new very wide modulation permanent-magnet generator; and then develop two structure prototypes and build voltage waveform experimental equipment to study them. Finite element analysis and prototype experiments show that the pole width modulation method is one of the effective and feasible technologies on reducing the voltage harmonic of PM Wind Generator.

Abstract: Wedge/aspheric lens element is a combination of wedge prism and aspheric lens as a single piece component forming a decentred lens, which plays an important role in the fields of liquid crystal projection display, laser fusion, high-energy laser, satellite optical system and large astronomical telescope, etc. Wedge/aspheric lens element are primarily manufactured by CNC machining, especially 3-axis CNC grinding. This paper presents a facile tool path generation approach based on space coordinate transformation. The proposed method can be used to improve and automate three-axis Wedge/aspheric lens element machining for CAD/CAM systems. As part of the validation process, the tool paths generated are analyzed to compare with the desired part.

Abstract: When the dirt was cleaning away by the ultrasonic cleaning device, the insulating layer of the motor winding would be destroyed and the motor safety would be affect. The destructive effect mechanism is analyzed, a enameled wire-based destructive experiment method was designed. Finally the selection of cleaning power and time were realized. It was indicated by the motor experiments that the cleaning parameters selected in this way didn’t destroy the insulating layer of the motor winding, and was an excellent method to ensure the safety and reliability of the designed ultrasonic cleaning method.