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为了研究起爆偏心对聚能射流的影响,运用有限元软件LS-DYNA模拟了不同起爆偏心量(0.025Dk~0.125Dk,Dk为装药直径)下射流成型及其破甲过程,探究了药型罩非对称压垮程度、射流形态以及横向速度的变化规律,建立了理论模型以分析不同偏心量下射流横向速度分布情况,并基于正交试验设计理论和方差分析法揭示了各因素对评价指标影响程度的显著差异。结果表明:药型罩非对称压垮程度及射流横向速度均与偏心量呈正相关变化趋势。偏心量为0.025Dk时,射流侵彻深度仅下降0.7%;偏心量为0.050Dk时,侵彻深度下降突跃为12.4%;随着偏心量的增加,侵彻深度继续下降。此外,适当增大壁厚、罩顶装药高度可削弱起爆偏心对射流横向速度的影响。 相似文献
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大视场星敏感器标定技术研究 总被引:7,自引:1,他引:6
大视场星敏感器光学系统,由于畸变量较大,在轨标定过程中,直接采用最小二乘最优估计(LMS)或扩展卡尔曼滤波方法(EKF)无法精确求解其标定参数。在深入分析星敏感器测量误差因素的基础上,对考虑畸变和不考虑畸变两种情况的在轨标定结果进行了仿真对比;指出了标定焦距之前需先标定光学畸变的必要性,并介绍了4种可用于在轨校正光学畸变的方法;提出先标定主点偏差,再标定光学畸变参数,最后标定焦距的标定方法。仿真结果表明,可以采用像面旋转法求取主点偏差,利用高阶多项式方法求取光学畸变参数,畸变校正后,采用LMS和EKF标定算法估计焦距,标定精度达到了3.1μm和2.2μm。对100幅模拟星图处理后,星间角距统计偏差约为传统在轨标定方法的1/10~1/8。 相似文献
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The modulation effect of substrate doping on multi-node charge collection and single-event transient propagation in 90-nm bulk complementary metal-oxide semiconductor technology 下载免费PDF全文
Variation of substrate background doping will affect the charge collection of active and passive MOSFETs in complementary metal-oxide semiconductor (CMOS) technologies, which are significant for charge sharing, thus affecting the propagated single event transient pulsewidths in circuits. The trends of charge collected by the drain of a positive channel metal-oxide semiconductor (PMOS) and an N metal-oxide semiconductor (NMOS) are opposite as the substrate doping increases. The PMOS source will inject carriers after strike and the amount of charge injected will increase as the substrate doping increases, whereas the source of the NMOS will mainly collect carriers and the source of the NMOS can also inject electrons when the substrate doping is light enough. Additionally, it indicates that substrate doping mainly affects the bipolar amplification component of a single-event transient current, and has little effect on the drift and diffusion. The change in substrate doping has a much greater effect on PMOS than on NMOS. 相似文献
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New insight into the parasitic bipolar amplification effect in single event transient production 下载免费PDF全文
In this paper, a new method is proposed to study the mechanism of charge collection in single event transient (SET) production in 90 nm bulk complementary metal oxide semiconductor (CMOS) technology. We find that different from the case in the pMOSFET, the parasitic bipolar amplification effect (bipolar effect) in the balanced inverter does not exist in the nMOSFET after the ion striking. The influence of the substrate process on the bipolar effect is also studied in the pMOSFET. We find that the bipolar effect can be effectively mitigated by a buried deep P+-well layer and can be removed by a buried SO2 layer. 相似文献
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Temperature and drain bias dependence of single event transient in 25-nm FinFET technology 下载免费PDF全文
In this paper,we investigate the temperature and drain bias dependency of single event transient(SET) in 25-nm fin field-effect-transistor(FinFET) technology in a temperature range of 0-135°C and supply voltage range of 0.4 V-1.6 V.Technology computer-aided design(TCAD) three-dimensional simulation results show that the drain current pulse duration increases from 0.6 ns to 3.4 ns when the temperature increases from 0 to 135°C.The charge collected increases from 45.5 fC to 436.9 fC and the voltage pulse width decreases from 0.54 ns to 0.18 ns when supply voltage increases from 0.4 V to 1.6 V.Furthermore,simulation results and the mechanism of temperature and bias dependency are discussed. 相似文献
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室温和低热固相反应在合成化学中的应用 总被引:16,自引:0,他引:16
介绍了室温和低热固相反应的监测手段和影响因素。总结了它在金属原子簇化合物、多酸、简单配位化合物、亚稳态化合物合成以及材料化学和生产实际中的应用。 相似文献
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