Nowadays, the power semiconductor devices have been used in many fields like wind power generation systems, the rail transit. Bipolar junction transistors (BJTs) and metal-oxide-semiconductor field-effect transistors (MOSFETs) as well as some other devices are the dominating the market. The insulated gate bipolar transistor (IGBT) as a mixed device of the BJT and the MOSFET, has a preeminent performance. In this paper, the characteristics of the punch through IGBT (PT-IGBT), the MOSFET and the BJT will be investigated by TCAD. Then the PT-IGBT is compared with the BJT and the MOSFET, for concluding its advantages. According to the simulation result, the PT-IGBT has the on-state current of 9*10-4A and the forward blocking voltage of 1200V, which are much higher than the other two devices. In the end of the paper, the development of the semiconductor devices is predicted, about the research trends.

In the process of Heavy NC machine tool design, the combination of static, dynamic characteristics directly determines and influences stiffness, damping, machining precision and work efficiency, Therefore the research on the combination of the characteristics become extremely important to the success of machine tool design. This study mainly studies the dynamic and static characteristic parameters of heavy machine tool guide way joint. And put forward a practical machine tool combining surface analysis method according to the experimental verification. How to obtain the analysis and test of the dynamic parameters to the combination is introduced. It is presented that small linear guide as a scale model based on similarity theory. And make a research on the static and dynamic characteristics of small guide joint and the conclusion extended to heavy machine set of faces. And the conclusion is extended to the heavy machine set of faces. It is introduced the spring damping unit of combined surface characteristics simulation during a small test about guide way dynamic performance analysis. Thus it can more effective simulate influence of combination of surface characteristics to components of the overall structure.The study analyze the dynamic performance of machine tool bed rail section by the verification and treat extraction of the first five modes as the analysis and forecast of the models of guide-way joint dynamic performance. The results can be used as reference data about structure and design of the machine tool due to the similarity principle and error range.

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