火灾区域模拟原理及CFAST软件应用

分析火灾区域模型的理论基础 ,介绍CFAST软件的功能及操作 ,并应用该软件对某建筑物二楼舞厅的火灾安全性进行评估     

舰舰协同防空的舰空导弹杀伤区分析

针对舰艇编队协同防空时的耦合杀伤区形状及纵深等问题进行了研究,以定量地对编队耦合杀伤区进行简化描述。分析了单舰对典型目标的杀伤区特性,探讨了舰艇编队的典型防空队形,研究了纵向上递阶多层次、横向上同阶耦合的"递阶封闭圈原理"。以一阶耦合杀伤区为重点,依据攻击目标的不同,将其分成相对航路捷径为零和相对航路捷径均非零两类情况建立了耦合杀伤区纵深的计算模型,并扩展到了高阶耦合的情况。研究了耦合杀伤区与舰舰间距和来袭目标进攻舷角等参数的相互关系以及灵敏度。结果表明建立的模型符合实际,具有一定的指导意义。     

Effects of nano-sized aluminum on detonation characteristics and metal acceleration for RDX-based aluminized explosive

Nano-sized aluminum(Nano-Al)powders hold promise in enhancing the total energy of explosives and the metal acceleration ability at the same time.However,the near-detonation zone effects of reaction between Nano-Al with detonation products remain unclear.In this study,the overall reaction process of 170 nm Al with RDX explosive and its effect on detonation characteristics,detonation reaction zone,and the metal acceleration ability were comprehensively investigated through a variety of experiments such as the detonation velocity test,detonation pressure test,explosive/window interface velocity test and confined plate push test using high-resolution laser interferometry.Lithium fluoride(LiF),which has an inert behavior during the explosion,was used as a control to compare the contribution of the reaction of aluminum.A thermochemical approach that took into account the reactivity of aluminum and ensuing detonation products was adopted to calculate the additional energy release by afterburn.Combining the numerical simulations based on the calculated afterburn energy and experimental results,the param-eters in the detonation equation of state describing the Nano-Al reaction characteristics were calibrated.This study found that when the 170 nm Al content is from 0％to 15％,every 5％increase of aluminum resulted in about a 1.3％decrease in detonation velocity.Manganin pressure gauge measurement showed no significant enhancement in detonation pressure.The detonation reaction time and reaction zone length of RDX/Al/wax/80/15/5 explosive is 64 ns and 0.47 mm,which is respectively 14％and 8％higher than that of RDX/wax/95/5 explosive(57 ns and 0.39 mm).Explosive/window interface velocity curves show that 170 nm Al mainly reacted with the RDX detonation products after the detonation front.For the recording time of about 10 μs throughout the plate push test duration,the maximum plate velocity and plate acceleration time accelerated by RDX/Al/wax/80/15/5 explosive is 12％and 2.9 μs higher than that of RDX/LiF/wax/80/15/5,respectively,indicating that the aluminum reaction energy significantly increased the metal acceleration time and ability of the explosive.Numerical simulations with JWLM explosive equation of state show that when the detonation products expanded to 2 times the initial volume,over 80％of the aluminum had reacted,implying very high reactivity.These results are significant in attaining a clear understanding of the reaction mechanism of Nano-Al in the development of aluminized explosives.     

防空目标分配中雷达遮蔽区问题研究

目标分配是防空指挥控制的主要任务,而目标相对于防空导弹火力单元的遮蔽判断是目标分配必须考虑的重要因素。分析了目标遮蔽区的判断条件,推导出目标在遮蔽区飞行时间的计算方法,提出了一种快速表示遮蔽区域图的离散处理方法,并研究了考虑目标遮蔽区影响的目标分配问题。通过实例计算,验证了目标遮蔽计算判断和分配方法的合理性,研究结果对实时指挥控制有应用价值。     

抗滑短桩与桩周土共同作用的探讨

根据某工程的应力监测结果和ANSYS计算结果,就抗滑短桩与桩周土共同作用进行探讨,得出了两点认识：第一,考虑桩土接触带贡献作用和桩-土共同工作是更趋于实际情况的,也是更经济合理的;考虑比不考虑桩土接触带的贡献,作用在抗滑短桩上的剩余水平下滑力约小10%。第二,接触带采用合适的弹性模量和厚度进行计算的结果与监测结果相当接近(相差≯5%)。     

Killing Your Own: Confronting Desertion and Cowardice in the British Army During the Two World Wars

Military units can become to some extent self-governing in war-time battle. At times, they may take the discipline of their soldiers into their own hands and such discipline may be severe. This paper examines incidents in the British military, in both World Wars, where British soldiers were killed by their comrades because they would not fight in the heat of battle. The judicial execution by the military authorities of deserters in the First World War led to much controversy in Britain. It may be much less well-known that in both World Wars there was, on occasion, an extra-judicial practice within the British military of executing soldiers who would not fight in the heat of battle. In such situations ethical dilemmas become very difficult indeed and some of the relevant issues are examined here.     

Hybrid War and Its Countermeasures: A Critique of the Literature

This article examines critically the literature of hybrid war and evaluates the countermeasures often proposed. It explains the concept of hybrid warfare and its varied interpretations, illustrating how it is a manifestation of current anxieties in armed conflict. The selection of the literature is based on works that are referenced, that offer a scientific approach, and which review either the phenomenon of hybrid warfare or its countermeasures empirically. Unscientific works have been omitted. The analysis of the literature presented here shows that the antidotes to ‘hybridity’ lie not in the operational or tactical sphere but in strategic and political domains.     

超声速燃烧火焰放热区结构CH-PLIF成像技术

超燃冲压发动机是吸气式高超声速飞行器的关键部件之一,超燃冲压发动机燃烧室内火焰结构的研究对揭示超声速燃烧的稳焰机理具有重要意义。利用平面激光诱导荧光（Planar Laser-Induced Fluorescence,PLIF）技术测量了超声速燃烧直连式试验台燃烧过程中重要自由基CH的二维分布,实现了超声速燃烧火焰放热区结构的可视化。在开敞空间的低速射流火焰炉中使用甲烷/空气预混火焰对CH-PLIF技术进行了初步验证和系统优化,再利用CH-PLIF技术在凹腔稳焰的超燃直连台上实现了超声速燃烧火焰放热区结构的二维可视化,并与OH-PLIF和CH自发辐射测量结果进行了对比。实验结果表明,在开敞空间的低速射流预混火焰中,火焰放热区会发生扭曲、褶皱和分裂等现象,随着雷诺数的增大,火焰锋面褶皱程度更加显著;在凹腔稳焰的超声速燃烧中,火焰放热区高度褶皱和破碎,放热区结构的厚度为0.5～6.5 mm,同时也存在放热区的分裂与剥离等现象。CH-PLIF技术能够以较高的空间分辨率更准确地呈现凹腔超声速火焰放热区的结构,其在凹腔稳焰的超声速燃烧诊断中具有重要的应用价值。     

非均匀焊接接头的力学建模与断裂分析

建立了非均匀焊接接头"4区连接"的新模型,并利用积分变换-奇异积分方程的方法,研究了焊缝区的反平面断裂问题。数值计算表明:增大界面区的刚度或者适当地增大焊缝区、热影响区和界面区的宽度都有利于降低焊缝区裂纹的应力强度因子;相对于高匹配情形而言,低匹配焊接接头焊缝区的抗断裂能力明显较高。     

城市区域消防安全评估方法研究

城市区域消防安全评估是科学有效地进行城市消防规划、部署和消防法规的制定的重要依据 ,对于城市建设和社会经济的协调发展具有保证和促进作用。根据《中华人民共和国消防法》及《机关、团体、企业、事业单位消防安全管理规定》(6 1号令 )对消防管理对象的界定标准 ,提出两种不同的分类方法 ,确定了城市区域消防安全体系的组成要素 ,采用层次分析法确定了各要素的权重 ,应用多层次多目标系统模糊优选理论 ,建立了城市区域消防安全评价模型 ,对城市区域消防安全评估进行了方法研究和具体计算 ,并应用所设计的模型对北京市宣武区的区域消防安全状况进行了两种方法的分析评估。计算结果证明了方法的有效性 ,用两种不同的分类方法所做出的结果 ,显示了不同分类的一致性。