Power dissipation characteristics of great power and super high speed semiconductor switch

The power dissipation characteristics of pulsed power switch reversely switched dynistors （RSDs） are investigated in this paper. According to the expressions of voltage on RSD, derived from the plasma bipolar drift model and the RLC circuit equations of RSD main loop, the simulation waveforms of current and voltage on RSD are acquired through iterative calculation by using the fourth order Runge-Kutta method, then the curve of transient power on RSD versus time is obtained. The result shows that the total dissipation on RSD is trivial compared with the pulse discharge energy and the commutation dissipation can be nearly ignored compared with the quasi-static dissipation. These characteristics can make the repetitive frequency of RSD increase largely. The experimental results prove the validity of simulation calculations. The influence factors on power dissipation are discussed. The power dissipation increases with the increase of the peak current and the n-base width and with the decrease of n-base doping concentration. In order to keep a low power dissipation, it is suggested that the n-base width should be smaller than 320μm when doping concentration is 1.0×10^14cm^-3 while the doping concentration should be higher than 5.8×10^13cm^-3 when n-base width is 270μm.     

利用线阵CCD测量液体折射率实验研究

提出一种利用线阵CCD测量液体折射率的方案,平行光束经过透镜汇聚,在汇聚点处设置线阵CCD检测光束直径大小,在透镜后加入液体,光束发生折射,利用线阵CCD测量出光束直径变化量,即可测量得液体的折射率。实验测量得蒸馏水、乙醇液体的折射率与标准值吻合,相对误差小于0.4%。对不同折射率的液体,只需测量出光束直径变化量即可测量出折射率。本方案结构简单、测量操作简化、测量准确,在物理实验教学和折射率测量仪研制中具有应用价值。