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Designed for 6500V 4H-SiC JBS diodes, a highly-efficient termination structure of a non-uniform multiple floating field limiting rings (MFFLR) featuring with a non-uniform ring spacing and a multiple region division is studied and purposed. For each region, ring spacing is modulated independently by a multiplication factor and a linear increment factor. The non-uniform MFFLR structure is simulated and optimized for a better electric field distribution and a higher breakdown voltage. Based on the simulation results, 4H-SiC JBS diodes with the optimized non-uniform termination designs are fabricated. Experimental results show that the SiC JBS diode with optimized non-uniform MFFLR termination structure can achieve a breakdown voltage of up to 7800 V, and its termination efficiency is about 94% of an ideal parallel-plane junction’s. Our results demonstrate that the optimized non-uniform MFFLR termination structure is capable for SiC JBS diodes with breakdown voltage of 6500V and above. Our results can provide a valuable design methodology of edge termination structures for other high-voltage SiC devices.

70-um thick homoepitaxial layers with very low defect density were grown on 6-inch 4° off-axis wafers using hot-wall chemical vapor deposition (CVD). Process optimization resulted in reduction of the density of triangular defects from 1.01 cm-2 to 0.14 cm-2. The treatment of wafer (CMP or selection) was essential. The in-situ etch process was optimized prior to the epitaxial growth. Junction Barrier Schottky diodes fabricated on the epitaxial films presented a typical I–V characteristic and a block voltage of 6500 V.

The practice of artificial tracheal prosthesis has been a major challenge to the entire surgical field worldwide until now. The previously applied prosthesis is “inner stent” type, which is unable to heal biologically with native trachea.[1] The newly developed design, the Zhao's artificial trachea, uses a memory alloy mesh combined with traditional operation procedures. Following a 2-year experimental period, the device has been applied to seven patients with satisfying results. We believe this to be a successful artificial trachea that is capable of complete biologically healing with the native trachea. No rejection, infection, or major complications were present in the seven patients, and the Zhao's artificial trachea may be considered a real part of the trachea.

This article establishes a model of industrial structures evolution law by sustainable development method. Making use of the data from 1993 to 2012 in China, the author simulates the evolution of three industries outputs. Then, the author analyses the law and inducement of industry structures evolution in China, and gives advices on sustainable development of industrial structure upgrading.

The course PLC has the characteristics of strong applicability and practicality. Currently, in the course of teaching it exits many shortcomings such as the single teaching form, having less intuitive and vivid, contacting with the other professional courses not closely and so on. Based on this, the paper proposes a project-driving teaching method using the multimedia technology integrating with much knowledge of the professional courses. The teaching method can melt the boring theory learning to the specific project to enrich teaching content, enhance students' learning interest and improve the comprehensive application ability of specialized knowledge of students. Index Terms - PLC, the project-driving teaching, integration of multi professional courses

In view of the serious misalignment, the mathematical model's uncertainty, the characteristic of the system operating point changing fiercely of the heating furnace temperature control system, this paper designed a new type of intelligent control system - PID neural network system (PIDNN) which melt the PID control rule in the neural network. This system has the quick reasoning speed and the strong anti-interference ability.

In this study, blind source separation (BSS) method was applied to separate the multi-channel fault vibration signals generated by a rotor. As the signals were non-stationary, an algorithm based on spatial time-frequency distributions was applied to the experimental vibration signals to obtain the non-stationary vibration sources that were mutually independent. Further, AR modeling estimates of these sources were calculated with BURG method. A neural network was applied to the AR modeling parameters to perform the fault classification. The separation results of an experiment on a rotor’s multi-fault show that this method is feasible for fault diagnosis.

Objective To observe the effects of bloodletting puncture at Jing-Well points in the distal ends of the finger and toe on survival rate, survival time, and brain edema in rats with cerebral ischemia. Methods Fifty-four male Sprague-Dawley rats were randomly divided into five groups: normal, sham operation, model, bloodletting puncture at Jing-Well points in distal ends of finger and toe, and puncture without bloodletting at these points. Middle cerebral artery occlusion models were established according to Longa's method. The brains were taken 48 h after the model was established. Brain water content, brain density, brain coefficient, survival rate, and survival time in each group were measured. Results After bloodletting puncture, the survival time of the rats was prolonged, their brain water content and brain coefficient were reduced, and brain density was increased. Conclusion Bloodletting puncture at Jing-Well points in the distal ends of the finger and toe can improve function in ischemic brain edema.