Damage mechanics and energy absorption capabilities of naturalfiber reinforced elastomeric based bio composite for sacrificial structural applications

The present study deals with the experimental, finite element (FE) and analytical assessment of low ballistic impact response of proposedflexible'green' composite make use of naturally available jute and rubber as the constituents of the composite with stacking sequences namely jute/rubber/jute (JRJ), jute/rubber/rubber/jute (JRRJ) and jute/rubber/jute/rubber/jute (JRJRJ). Ballistic impact tests were carried out by firing a conical projectile using a gas gun apparatus at lower range of ballistic impact regime. The ballistic impact response of the proposed flexible composites are assesses based on energy absorption and damage mechanism. Results revealed that inclusion of natural rubber aids in better energy ab-sorption and mitigating the failure of the proposed composite. Among the three different stacking se-quences of flexible composites considered, JRJRJ provides better ballistic performance compared to its counterparts. The damage study reveals that the main mechanism of failure involved in flexible com-posites is matrix tearing as opposed to matrix cracking in stiff composites indicating that the proposedflexible composites are free from catastrophic failure. Results obtained from experimental, FE and analytical approach pertaining to energy absorption and damage mechanism agree well with each other. The proposed flexible composites due to their exhibited energy absorption capabilities and damage mechanism are best suited as claddings for structural application subjected to impact with an aim of protecting the main structural component from being failed catastrophically.     

Investigate the effects of magnetic fields on the penetration ability of a shaped charge jet at different standoffs

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.     

某供弹机构现存问题动力学分析及参数优化探讨

介绍了环形杠杆供弹机构的工作原理及其在实际使用中常见的问题,建立了机构的动力学模型,对模型进行动态求解,模拟了机构的工作过程。借助求解结果,针对问题产生的原因进行了动力学分析,在理论上找到了问题产生的根源。在此基础上建立了机构的最优化数学模型,给出了优化方案,最后对优化方案和现有结构进行了比较。     

射频识别系统的多目标识别-反碰撞算法

对多目标识别技术的二进制搜索算法、时隙ALOHA算法进行了剖析,并对ALOHA算法用概率论和数理统计的方法进行了深入的理论分析,得出要根据所设计的射频识别系统的特点合理采用各种算法方可得到良好的效果.该算法的实现对提高高速公路上自动收费系统、人员和物流管理等各领域的工作效率具有一定的指导意义.     

论军队院校科研管理资源配置机制建设

分析了目前军队院校科研管理资源配置机制中存在的问题及原因,提出了军队院校建立科学高效优化合理的科研管理资源配置机制的基本思路:建立基于学科的资源优化配置机制;建立和完善资源开放平台和共享机制;建立尊重和适应市场规律、科学合理的人才资源配置机制。     

氧化钨薄膜电致变色机理的探讨

研究磁控溅射生成的氧化钨薄膜处于电解液系列中的循环伏安特性,充电电流及光学特性.采用配体场理论来解释氧化钨薄膜在电场作用下,锂离子注入引起薄膜变色的现象,认为注入的锂离子破坏了薄膜界面层内氧化钨分子的八面体结构的对称性,在内部静电场和外部电场的共同作用下,钨离子d轨道的五重简并能级分裂,从而使得薄膜对可见光产生d-d吸收,导致氧化钨薄膜变色.     

面向决策的一体化建模方法及其在兵力筹划中的应用

在对军事决策问题的主要特点进行分析的基础上,提出从军事概念模型到数学模型再到定性推理模型的一体化建模思想.以空军航空兵遂行直接航空火力支援任务为想定背景,根据EATI模板,利用基于UML的Rose工具依次对想定任务的实体、任务、交互等进行分析;对于兵力筹划中的结构化问题建立了机会约束多目标规划数学模型;对于非结构化问题则构造了推理机,推理机体现了定量与定性相结合的决策分析思想.最后,以一个实例验证文章思路的可行性.     

潜艇运动对被动声纳浮标搜索的影响

由于被动声纳浮标隐蔽持续探测,潜艇可能由于机动进入浮标探测范围,从而增加了被探测概率。首先,在分析已有模型局限性的基础上,从潜艇运动对浮标搜索影响的原理出发,建立单枚浮标新增搜索区域模型,分析了单枚浮标搜索概率的影响因素,然后建模分析了潜艇运动对浮标拦截线搜索概率的影响因素,得出了影响作用仅对浮标作用距离、间距和航向敏感的结论,并对作战使用方法提出相关建议。     

阈下知觉研究的三个层面

阈下知觉的研究有三个层面,第一是阈下知觉的存在及影响效果研究;第二是阈下知觉的心理机制的研究;第三是阈下知觉的应用研究.在这三个层面中,阈下知觉的存在及影响效果研究最为成熟,实验范式最为完善,数据最有说服力;阈下知觉的心理机制研究属于偏理论性的研究,争议还比较多,需要进一步探讨;阈下知觉的应用研究具有广阔的发展前景,社会价值高.基于这三个层面建立阈下知觉研究的体系不仅具有理论研究的意义,也具有实践应用的意义.     

兵团音乐的创作机制、题材类型与思想教育功能

"兵团音乐"这一语辞包含区域、主题、风格、功能、情感等多重属性。本论文尝试从兵团音乐的特质、兵团音乐创作机制的类型、兵团音乐创作主题的类型三方面来阐释兵团音乐的思想教育功能。