High current pulse forming network switched by static induction thyristor

A high-current pulse forming network (PFN) has been developed for applications to artificial solar-wind generation. It is switched by staticinduction thyristor (SIThy) and is capable of generating pulsed current of ~9.7 kA for a time duration of ~1 ms. The SIThy switch module ismade that it can be controlled by an optical signal and it can be operated at elevated electrical potential. The experiments reported in this paperused two switch modules connected in series for maximum operating voltage of 3.5 kV. The experimental results have demonstrated a pulsedhigh-current generator switched by semiconductor devices, as well as the control and operation of SIThy for pulsed power application.

Optimization of press bend forming path of aircraft integral panel

In order to design the press bend forming path of aircraft integral panels,a novel optimization method was proposed, which integrates FEM equivalent model based on previous study,the artificial neural network response surface,and the genetic algorithm.First,a multi-step press bend forming FEM equivalent model was established,with which the FEM experiments designed with Taguchi method were performed.Then,the BP neural network response surface was developed with the sample data from the FEM experiments.Furthermore,genetic algorithm was applied with the neural network response surface as the objective function. Finally,verification was carried out on a simple curvature grid-type stiffened panel.The forming error of the panel formed with the optimal path is only 0.098 39 and the calculating efficiency has been improved by 77%.Therefore,this novel optimization method is quite efficient and indispensable for the press bend forming path designing.

Characteristics of road network forms in historic districts of Japan

This study focused on the structure and the platform of the road space of historic districts. We analyzed the road networks of 16 historic districts in Japan from the perspectives of circularity, accessibility and indirection based on graph theory. By calculatin8 and comparing the indexes of each road network （NW1 and NW2） forms, we quantitatively describe the effects of the main prefectural roads （more than 4 m in width） and narrow streets （less than 4 m in width） on the spatial characteristics. And it turned out that we could divided the 16 objective historic districts into 4 types. Moreover, we qualitatively studied the characteristics of each type of historic districts based on their development background and the structure of road network.

Design of Pulse Power Supply for CSNS Extraction Kicker Magnet

A 40kV/6kA pulsed power supply was designed for the Rapid Cycling Synchrotron(RCS)extraction kicker magnet of the China Spallation Neutron Source.The calculation of the pulsed power supply's parameters,the design of power supply's system,the optimization of pulse forming network(PFN)are introduced in this paper.The magnet current pulse waveform is simulated by PSpice program in the situation of 36.5kV charging voltage.The simulation explains the influence of the PFN section number and the transmission cable length on the magnet current pulse.

Investigation of Marx-PFN

The principle of Marx-pulse forming networks(PFN)is introduced in this paper.The PSpice simulation result of the Marx-PFN is presented and a smooth waveform is obtained in the condition of equal capacitance.Through optimizing the parameters of the networks,a 4-stage Marx-PFN has been built,a 40kV output with a FWHM of 3μs and a fiat-top of 2μs is obtained on the marched resistance of 18Ωwhen the Marx-PFN is changed to 20kV.