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基于生物受激发光与流场机械刺激间的相关性,构建了库埃特流场刺激下的生物受激发光实验平台,分析了影响生物发光的水动力因素剪应力。实验结果显示:引起多边膝沟藻受激发光的剪应力阈值为0.1 N/m2;当流场中的剪应力大于发光阈值后,生物发光强度随着剪应力的增大而增强。采用FLUENT软件模拟计算了不同航速下某潜艇尾流场中的剪应力,计算结果表明:剪应力随着尾流长度的增加而减小,在近场区域剪应力出现了类似正弦波振荡的减小,且航速越大减幅越大,减速越快;当潜艇航速大于4.1 m/s航行时, 2 000 m处尾流的剪应力仍然大于引起生物发光的剪应力阈值。 相似文献
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为了了解激光声在液体中的传输特性,理论分析了激光声的传输特性,并采用高速照相机、光纤MEMS水听器对激光声进行了实验研究,利用小波变换对采集的不同位置上的激光声信号各级频谱特性进行了分析。结果表明:激光声属于一种脉动球源,激光声信号传输过程中幅度与距离成反比关系;激光声的分析频带内存在明显的优势频率,峰值频率稳定在3.1 kHz,带宽稳定在3 kHz;低频信号的能量占总能量的70%以上,高频部分主要是噪声;从功率谱波形分析看,低频信号的强度幅值随时间、距离变化衰减较慢,而高频噪声随时间、距离变换衰减较快。 相似文献
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The changes of performence of AlGaAs/GaAs heteroface solar cell after 1 -MeV electron irradiation has been studied by the experimental and numerical fitting. Using an improved damped least square method, the spectral response and dark J-V characteristic of the cells are fitted according to the various theoretical formulas. From the fitting calculation, a number of materials, structural and electric parameters of the cell are obtained. The experimental data and calculated results show that the critical irradiation flux of the cell is about 2.2×1014 cm-2, the damge constant KL for the minority carrier diffusion length in n-GaAs layer due to irradiation is found to be larger than that in p-GaAs, layer, they are about 7.0×10-3 and 2.2×10-7, respectively, the degradation of the minority carrier diffusion length in p-GaAs layer and the increase in the recombination velocity at interfaec are the majar reasons for the cell performence degradation. The cell with a shallow junction has higher irradiation resistance than the one with a deep junction. Based on the studies, the method for improving the irradiation resistance of the cell is discussed. 相似文献
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