Research on the influences of confining pressure and strain rate on NEPE propellant: Experimental assessment and constitutive model

In order to study the influences of confining pressure and strain rate on the mechanical properties of the Nitrate Ester Plasticized Polyether (NEPE) propellant, uniaxial tensile tests were conducted using the self-made confining pressure system and material testing machine. The stress-strain responses of the NEPE propellant under different confining pressure conditions and strain rates were obtained and analyzed. The results show that confining pressure and strain rate have a remarkably influence on the mechanical responses of the NEPE propellant. As confining pressure increases (from 0 to 5.4 MPa), the maximum tensile stress and ultimate strain increase gradually. With the coupled effects of confining pressure and strain rate, the value of the maximum tensile stress and ultimate strain at 5.4 MPa and 0.0667 s⁻¹ is 2.03 times and 2.19 times of their values under 0 MPa and 0.00333 s⁻¹, respectively. Afterwards, the influence mechanism of confining pressure on the NEPE propellant was analyzed. Finally, based on the viscoelastic theory and continuous damage theory, a nonlinear constitutive model considering confining pressure and strain rate was developed. The damage was considered to be rate-dependent and pressure-dependent. The constitutive model was validated by comparing experimental data with predictions of the constitutive model. The whole maximum stress errors of the model predictions are lower than 4% and the corresponding strain errors are lower than 7%. The results show that confining pressure can suppress the damage initiation and evolution of the NEPE propellant and the nonlinear constitutive model can describe the mechanical responses of the NEPE propellant under various confining pressure conditions and strain rates. This research can lay a theoretical foundation for analyzing the structural integrity of propellant grain accurately under working pressure loading.     

Maneuvering target tracking of UAV based on MN-DDPG and transfer learning

Tracking maneuvering target in real time autonomously and accurately in an uncertain environment is one of the challenging missions for unmanned aerial vehicles(UAVs).In this paper,aiming to address the control problem of maneuvering target tracking and obstacle avoidance,an online path planning approach for UAV is developed based on deep reinforcement learning.Through end-to-end learning powered by neural networks,the proposed approach can achieve the perception of the environment and continuous motion output control.This proposed approach includes:(1)A deep deterministic policy gradient(DDPG)-based control framework to provide learning and autonomous decision-making capa-bility for UAVs;(2)An improved method named MN-DDPG for introducing a type of mixed noises to assist UAV with exploring stochastic strategies for online optimal planning;and(3)An algorithm of task-decomposition and pre-training for efficient transfer learning to improve the generalization capability of UAV's control model built based on MN-DDPG.The experimental simulation results have verified that the proposed approach can achieve good self-adaptive adjustment of UAV's flight attitude in the tasks of maneuvering target tracking with a significant improvement in generalization capability and training efficiency of UAV tracking controller in uncertain environments.     

基于构件的软件复用技术在防化软件中的应用

软件复用是在软件开发过程中避免重复劳动的解决方案。通过构件的形式来实现软件复用,可以提高开发的效率和质量。以核侦察处理模块的实现和集成为例,介绍了基于构件的复用技术在目前信息化建设中的使用手段和方法。     

甲基三硫代膦酸二乙酯合成反应液的气相色谱-质谱分析

在OPCW第18次水平考试土样中检测到一未知化合物,经多种分析技术测定,判断可能是甲基三硫代膦酸二乙酯．对合成甲基三硫代膦酸二乙酯的反应液进行了气相色谱一质谱测定,并对此反应液中的部分产物进行了质谱解析．     

论陈毅军旅诗的人格魅力

陈毅素有“一代儒将”,“元帅诗人”之美誉,他的诗作多达350余篇,在社会上广为流传,其作品以大气磅礴的风格和正直不阿的人格著称。本文撷取陈毅军旅诗的名篇,从坚贞不渝的革命气节、不畏艰险的英雄气概、爱憎分明的坦荡胸怀等三个方面阐发陈毅诗词的人格魅力。     

非线性评估中权重的敏感性分析

分析了非线性评估中权重的敏感性问题,给出了分析的思路和计算方法,并得出判断权重敏感的方法,定义了多维权重的敏感度,并由算例说明评价值的敏感性和权重的关系.     

采用VXI总线研制电路板故障诊断系统

利用VXI总线技术研制了电路板故障诊断系统 ,并就其硬件和软件的组成进行了较详细的探讨 ,建立软件核心部分的测试诊断数据库时采用了一种全新的方法———离散事件系统法     

加入世贸组织对军队思想政治教育的新挑战

加入世界贸易组织直接影响的是经济领域 ,而透过经济框架 ,必将对置于经济生活之上的民族心理和情感、人们的思维方式、政治构架、思想政治教育等多方面产生深刻影响 ,并使之发生渐变和突变。军队作为社会的一部分 ,官兵的思想观念也必然会受到影响。如何使付出的“代价”最小 ,有效地减缓可能带来的冲击 ,使军队这个武装集团保持稳定 ,并能“打得赢”、“不变色” ?对此 ,必须及时进行研究 ,拿出对策。     

军人非正式群体心理探讨

本文运用社会学、社会心理学的非正式群体理论 ,分析了军人非正式群体的心理特征、心理作用 ,探讨了军人非正式群体良好心理的培养方式及不良心理的矫正问题 ,对军队思想政治工作与军队心理建设有启示     

渡海登陆战役中的心理战初探

在我军未来可能实施的渡海登陆战役作战中 ,心理战将成为现代战争的一种作战形式。渡海登陆战役中在军事心理上具有复杂性 ,对我军官兵的意志和士气提出了更高的要求 ,我军必须抢占政治制高点 ,构筑强大的精神支柱 ,主动对敌实施心理战。