Thermal explosion of a reactive gas mixture at constant pressure for non-uniform and uniform temperature systems

In this study, the approximate and exact solutions for the stationary-state of the solids model with neglecting reactant consumption for both non-uniform and uniform temperature systems were applied on gas ignition under a constant pressure condition. The criticality conditions for a slab, an infinite cylinder, and a sphere are determined and discussed using dimensionless temperatures under constant ambient and surface temperatures for a non-uniform temperature system. Exact solution for a Semenov model with convection heat loss was also presented. The solution of the Semenov problem for constant volume or density as a solid and constant pressure were compared. The critical parameter δ is calculated and compared with those of Frank-Kamenetskii solution values. The validation of the calculated ignition temperatures with other exact solution and experimental results were offered. The relation between critical parameters form Semenov and F.K. models solution was introduced.     

A study on the surface overpressure distribution and formation of a double curvature liner under a two-point initiation

The formation mechanism of an EFP(explosively formed projectile) using a double curvature liner under the overpressure effect generated by a regular oblique reflection was investigated in this paper.Based on the detonation wave propagation theory,the change of the incident angle of the detonation wave collision at different positions and the distribution area of the overpressure on the surface of the liner were calculated.Three-dimensional numerical simulations of the formation process of the EFP with tail as well as the ability to penetrate 45# steel were performed using LS-DYNA software,and the EFP ve-locity,the penetration ability,and the forming were assessed via experiments and x-ray photographs.The experimental results coincides with those of the simulations.Results indicate that the collision of the detonation wave was controlled to be a regular oblique reflection acting on the liner by setting the di-mensions of the unit charge and maintaining the pressure at the collision point region at more than 2.4 times the CJ detonation when the incident angle approached the critical angle.The distance from the liner midline to the boundary of the area within which the pressure ratio of the regular oblique reflection pressure to the CJ detonation pressure was greater than 2.5,2,and 1.5was approximately 0.66 mm,1.32 mm,and 3.3 mm,respectively.It is noted that pressure gradient caused the liner to turn inside out in the middle to form the head of the EFP and close the two tails of the EFP at approximately 120μs.The penetration depth of the EFP into a 45# steel target exceeded 30 mm,and there was radial expansion between the head and tail of the EFE increasing the penetration resistance of the EFP.Therefore,the structural size of the unit charge and the liner can be further optimized to reduce resistance to increase the penetration ability of the EFP.     

Terrorism research: should we focus on the opponent or on our own people?

In terrorism research, three different sources of information and data exist: the terrorists and their environment; the incidents; and the population. This article discusses the strengths and weaknesses of research that is concerned with, or relies on, any of the mentioned sources. An in-depth understanding of the methodological issues that come with these sources is important to correctly interpret results from scientific studies. It is highlighted how the different scientific approaches add to a holistic view of terrorism as a phenomenon. Furthermore, the double-edged sword of information in the field of terrorism is discussed. From these deliberations, guidance concerning the future work of both scholars and decision-makers can be deducted.     

非对称相互依赖下的美日军事同盟机制分析——以奥巴马政府“重返亚太”为视角

2012年1月5日,美国国防部发表了《保持美国的全球领导地位:21世纪的防务重点计划报告》,在"重返亚太"战略的战略背景下,重点针对美国未来的军事力量结构、全球部署态势、军事战略目标等进行了重新规划。新军事战略调整对整个国际格局和地区性大国产生深远影响。随着美国重返亚太的战略调整,军事上的相互依赖程度体现在美日同盟之间尤为突出。本文仅从军事战略角度,运用《权力与相互依赖》中部分理论对其调整下的美日军事同盟机制进行分析。     

试论科技进步与中国国际责任的现实担当

当代科技进步不仅影响着世界格局的变革,也深刻影响着国家的外交行为。随着中国经济实力和科技实力的快速发展,中国更为主动、自信地以大国身份融入国际社会,在几乎所有重要的全球性国际机制中都发挥着积极作用,遵守和履行相应的规则和义务,承担为国际社会提供公共产品以及维护正常合理的国际秩序等国际责任。但随着全球问题的不断增多,国际社会对中国承担更多国际责任的期待也在增多,有些西方国家甚至要求中国承担超出能力的国际责任。面对错综复杂的新形势,中国应该清醒认识自身的国际角色定位,在确保自身崛起的前提下,以科技实力和综合国力承担起力所能及的国际责任,为中国的和平发展提供更广泛的认同基础。     

推进国防动员军民融合深度发展的对策思考

军民融合式发展是实现富国与强军相统一的必由之路,也是增强国防动员潜力、提高国防动员能力的有效途径。在新的形势下推进国防动员建设,必须进一步强化军民融合观念,完善军民融合机制,提高军民融合层次,增强军民融合实效,努力促进动员潜力随经济实力同步增长、动员能力随需求拓展不断提升,实现经济效益、社会效益与国防效益有机统一。     

量子保密通信技术前沿述评

量子保密通信是利用量子力学的基本原理来实现信息无条件安全传递的一种全新密码方法,其核心是量子密钥分发。2014年正好是量子保密通信的第一个协议—BB84协议提出30周年。经过30年的发展,量子保密通信在理论和实验上都得到了快速发展,实际工程应用也初具规模。文章对量子保密通信的历史发展及研究现状进行了简要回顾,特别介绍了基于实际量子保密通信系统的量子黑客和防御。最后,对未来的几个研究方向进行了简要讨论。     

多样化军事任务舆情演化及引导的仿真

针对海军遂行多样化军事任务所面临的日益复杂的社会舆论环境,采用基于Agent的建模理论与方法,建立了舆情演化过程的模型,并对其进行了仿真和分析。首先,提出了个体间观点交互的规则,建立了个体观点交互的舆情演化模型。其次,基于所建模型对不同条件下的舆情演化及引导进行了仿真实验与分析。仿真结果表明,模型的统计结果与实际舆情演化情况相符,具有较强的实际性。     

径向载荷作用下管道挤压变形过程数值模拟

野外埋地敷设的长距离输油管道发生断裂等较大事故时,采用管道局部挤压的方式可以在较短时间内将管道快速压扁以截断流油。为设计管道挤压截流装置,运用ANSYS Workbench建立上下压头加载作用下管道挤压的有限元模型,完成对ф159 mm×5 mm的45号钢挤压变形模拟仿真,得到管道挤压的等效应力、位移分布、变形范围和载荷-位移曲线等。将模拟数据与实验数据进行对比,两者结果比较吻合,可以为管道泄漏抢修提供理论和实践参考。     

未来数字化战场中的指挥控制语言研究

针对未来数字化战场中机器人部队指挥控制与协同作战这一新兴研究领域需解决的机-机协同和人-机智能融合等问题,综述国内外相关领域的研究现状,分析了构建我军指挥控制语言的必要性,研究了机器人部队指挥控制语言的技术架构与关键技术,并提出了指挥控制语言的一种形式化语法和语义标注方法和通信协议,并结合海军舰艇作战示例分析了指挥控制语言的可行性及有效性。