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991.
According to the parameters of a Brown Big-eared bat’s pinna,a simple obliquely truncated bat ear model that made by line and plane was designed,which was numerically simulated with finite element method.The change of far-field directivity was analyzed in elevation and azimuth as the frequency increased.The results show that,compared with the pinna of the Brown big-eared bat,the present model has the advantages in wider bandwidth of frequency driven scanning,better directivity in azimuth and larger angle scales in elevation. In addition,a wireless positioning method based on single base station could be achieved by using a frequency driven scanning antenna. 相似文献
992.
The superconducting spoke cavity has been proposed to accelerate the proton in the low energy section of high power proton linac for an Accelerator Driven Sub-critical System (ADS). Considering that the High Order Modes (HOMs) in the superconducting cavity have far reaching influence on power dissipation and beam stability, the analysis of HOMs of the spoke cavity is needed. In this paper, we put emphasis on the analysis of HOMs of the spoke cavity and the HOMs coupler design. 相似文献
993.
The evolution of nuclear disintegration mechanisms with increasing excitation energy, from compound nucleus to multifragmentation, has been studied by using the Statistical Multifragmentation Model (SMM) within a micro-canonical ensemble. We discuss the observable characteristics as functions of excitation energy in multifragmentation, concentrating on the isospin dependence of the model in its decaying mechanism and break-up fragment configuration by comparing the A0=200, Z0=78 and A0=200, Z0=100 systems. The calculations indicate that the neutron-rich system (Z0=78) translates to a fission-like process from evaporation later than the symmetric nucleus at a lower excitation energy, but gets a larger average multiplicity as the excitation energy increases above 1.0 MeV/u. 相似文献
994.
在航空航天领域,为了加速系统设计及测试进度,通常需要进行半实物实时仿真,即控制器用实物,受控对象采用数学模型。本文开发出了基于Matlab/Simulink的两相传热模块,并用其搭建了某机械泵驱动两相回路的实时动态模型。通过与实验的对比,验证了模型的可靠性,表明该模型满足实时要求,可以在下一步用于半实物仿真。 相似文献
995.
介绍了将 3-dB 功率分配器、模式转化器、耦合器、水负载等常规波导器件发展为单元模块集成部件的基于 PAM 概念的新一代低杂波天线,利用耦合模理论分析设计了TE10 模过渡段的结构参数,使用高频电磁场仿真软件 HFSS 进行结构仿真和参数优化,得到了过渡段长度为 370mm,驻波比为 1.0012、反射损耗为-65.... 相似文献
996.
1提出问题在讲授高中静摩擦力的概念时,许多教师会向学生强调:"受静摩擦力的物体一定是静止的"这种说法是错误的,原因是没有指定参考系,只能根据教材上的摩擦力概念,加上"相对"二字,即"产生静摩擦力的两个物体一定是相对静止的"这才是正确的.但是,汽车在不打滑的情况下,驱动轮所受的摩擦力为静摩擦力,而此时受静摩擦力的物体——汽 相似文献
997.
998.
Marek Szczotka 《Acta Mechanica Sinica》2011,27(1):44-55
A system designed for a rigid and flexible pipe laying purposes is presented in the paper.Mathematical and numerical models are developed by using the rigid finite element method(RFEM).The RFEM is an efficient solution in the time domain.Static and dynamic problems related to pipe installation are solved by taking the advantage of simple interpretation and implementation of the method.Large deformations of the pipe during spooling and when it is reeled out at sea are considered.A material model implemented is used to take into consideration nonlinear material properties.In particular,the full elasto-plastic material characteristics with hardening and Bauschinger effect are included.Dynamic analyses are performed and the results attached in this work demonstrates how the sea conditions influence the machinery and pipeline,assuming a passive reel drive system. The influence of several other operational parameters on dynamic loads is verified.An active system,implemented as a part of the mathematical model,improves the system performance.Some results are presented as well. 相似文献
999.
1000.
本文建立辐射驱动小收缩比(5至10倍)的内爆靶丸的设计方法,并利用辐射流体力学程序Multi-1d对神光Ⅱ和神光Ⅲ原型装置的辐射驱动小收缩比内爆靶丸进行模拟计算,设计出小收缩比内爆靶丸的构形,计算结果给出压缩比、中子产额、压缩面密度随燃料压力变化等内爆物理参量.神光Ⅱ装置上的内爆靶燃料分别采用DD气体和DT气体两种;神光Ⅲ原型装置的内爆靶燃料采用DD气体.神光Ⅱ上小收缩比内爆实验结果与模拟结果基本一致,表明Multi-1d用于设计此类实验的可靠性.
关键词:
辐射驱动
小收缩比
内爆
面密度 相似文献