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151.
152.
A variational inhomogeneous image segmentation model based on fuzzy membership functions and Retinex theory is proposed by introducing the fuzzy membership function.The existence of the solution of the proposed model is proved theoretically.A valid algorithm is designed to make numerical solution of the model under the framework of alternating minimization.The last experimental results show that the model can make segmentation of the real image with intensity inhomogeneity effectively. 相似文献
153.
Jian-hao Dou Xin Jia Zheng-xiang Huang Xiao-hui Gu Ying-min Zheng Bin Ma Qiang-qiang Xiao 《防务技术》2021,17(3):846-858
The use of a shaped liner driven by electromagnetic force is a new means of forming jets. To study the mechanism of jet formation driven by electromagnetic force, we considered the current skin effect and the characteristics of electromagnetic loading and established a coupling model of"Electric—Magnetic—Force"and the theoretical model of jet formation under electromagnetic force. The jet formation and penetration of conical and trumpet liners have been calculated. Then, a numerical simulation of liner collapse under electromagnetic force, jet generation, and the stretching motion were performed using an ANSYS multiphysics processor. The calculated jet velocity, jet shape, and depth of penetration were consistent with the experimental results, with a relative error of less than 10%. In addition, we calculated the jet formation of different curvature trumpet liners driven by the same loading condition and ob-tained the influence rule of the curvature of the liner on jet formation. Results show that the theoretical model and the ANSYS multiphysics numerical method can effectively calculate the jet formation of liners driven by electromagnetic force, and in a certain range, the greater the curvature of the liner is, the greater the jet velocity is. 相似文献
154.
This work provides a method to predict the three-dimensional equivalent elastic properties of the filament-wound composites based on the multi-scale homogenization principle.In the meso-scale,a representative volume element(RVE)is defined and the bridging model is adopted to establish a theoretical predictive model for its three-dimensional equivalent elastic constants.The results obtained through this method for the previous experimental model are compared with the ones gained respec-tively by experiments and classical laminate theory to verify the reliability of this model.In addition,the effects of some winding parameters,such as winding angle,on the equivalent elastic behavior of the filament-wound composites are analyzed.The rules gained can provide a theoretical reference for the optimum design of filament-wound composites. 相似文献
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157.
Bin Ma Zheng-xiang Huang Zhong-wei Guan Xin Jia Xu-dong Zu Qiang-qiang Xiao 《防务技术》2021,17(5):1722-1730
The influence of a magnetic field on the stability of a shaped charge jet is experimentally investigated at standoffs of 490, 650 and 800 mm. The experimental results without and with the magnetic field are compared in terms of the shaped charge jet form, stability and penetration ability. A theoretical model based on one-dimension fluid dynamics is then developed to assess the depth of penetration of the shaped charge at those three standoffs and magnetic conditions. The results show that the penetration capability can be enhanced in more than 70% by the magnetic field. The theoretical calculations are compared with the experimental results with reasonably good correlation. In addition, the parameters introduced in the theory are discussed together with the experiments at three standoffs studied. 相似文献
158.
介绍了一种新颖ZCT推挽正激软开关升压电源主电路,对该主电路工作原理进行了详细分析,并对辅助谐振电路参数进行公式推导。利用MATLAB/ SIMULINK软件搭建了仿真模型,优化了主电路参数,记录了电路关键参数波形图。通过电路仿真验证了该电路工作原理分析的正确性,同时为ZCT推挽正激软开关升压电源的研制奠定了理论基础。首次提出了坦克炮控系统软开关技术。 相似文献
159.
坦克稳定器的神经滑模控制方法 总被引:1,自引:0,他引:1
针对坦克稳定器这一类非线性和不确定性的复杂控制对象,提出一种神经滑模控制方法。该方法将滑模控制与神经网络相结合,解决了控制系统跟踪性能和鲁棒性能之间的矛盾。系统中的滑模控制器保证了系统的快速跟踪性能;而神经网络具有很强的自学习功能,通过学习能够保证系统的稳定性,同时可对扰动和参数变化进行有效的抑制补偿,从而在不牺牲系统鲁棒性的同时达到削弱抖振的目的。从理论上证明了滑动平面的稳定性,并且通过仿真验证了该结果。仿真结果表明该设计方法优于经典设计,为实际设计提供了一种可行的新方法。 相似文献
160.
排队论在导弹防御体系射击效能中的应用 总被引:6,自引:0,他引:6
针对当前空袭手段多样化、综合化和一体化的特点,运用排队论方法,设计了一种基于排队论的射击效能评估模型。该模型综合考虑了各种因素对舰空导弹射击效能的影响,当编队的配置(如防御层数、通道数量)有所变化时,依然可以灵活运用上述模型对编队射击效能做出准确评估。 相似文献