火灾情况下地铁通风系统运行模式分析

分析了地铁在火灾情况下区间隧道和站台各种通风系统运行模式,以及通风系统有效运行所需达到的物理参数。对通风模式进行了分析,确定了火灾情况下最佳的通风方式。分析现行规范规定的数据,用临界风速公式进行计算得出区间隧道风速不满足通风要求。     

通风条件对测试厂房内推进剂毒气扩散影响的数值仿真

为获得某型导弹在测试厂房内发生推进剂泄漏后,推进剂蒸发产生毒气的扩散规律,开展了测试厂房通风条件对偏二甲肼泄漏蒸发形成蒸气的扩散过程数值研究,分析了通风风速5m/s时,测试厂房内有毒气体的浓度分布情况,以及不同进风风速、进风方向对偏二甲肼蒸气扩散的影响。研究结果表明,在所设定的泄漏状态下,通风系统以5m/s进风风速和水平进风风向工作时,有利于室内偏二甲肼蒸气的排出。     

某型旋翼无人机极限风速下运动失稳及失能特性研究

抗风能力是决定无人机应用范围和生存能力的关键.以某型旋翼无人机为研究对象,利用风洞试验设备和双目视觉非接触式测量系统,对无人机极限风速下的失稳特性(姿态或速度)以及动力组件的失能特性开展了精细化测量和研究,获得了某型旋翼无人机的临界失稳条件和特性以及易损部组件的失能特性.结果 表明:17 m/s为无人机的临界失稳风速,...     

基于Davenport风速谱的火箭及其发射平台风致响应分析

基于Davenport风速谱,采用M.Shinozuka法计算得到了三种不同基本风速下火箭芯级和助推器不同站点的风荷载时程样本,并调用MSC.Nastran软件对火箭及发射平台进行了瞬态响应分析,得到了停靠时不同基本风速下火箭及发射平台的位移响应。随着高度的增加,火箭芯级上各点的位移响应随之增加;不同基本风速下同一节点的最大位移之比约等于不同基本风速的平方之比。同时在脐带塔上设计了一个横拉减载结构,相同基本风速下的火箭位移响应明显减小,火箭及发射平台的抗风能力得到提高,对工程实际有较大的参考价值。     

高空风场条件风速概率分布与正态分布差异分析

在飞行器多学科优化设计中,高空风场是有重要影响的不确定性因素,需要准确获取其统计特性。高空风场条件风速的概率分布是特定的,为了便于将高空风场概率模型用于不确定性设计,减少计算量,提出了高空风场条件风速概率分布与正态分布差异的分析方法,给出了将高空风场条件风速概率分布简化为正态分布的适用条件。数值仿真结果表明:在纬度为24.3°N～42.2°N范围内,不同地区高空风场条件风速概率密度与正态分布概率密度的差异在海拔2～30 km范围内呈喇叭形分布,在海拔15 km附近,高空风场条件风速概率密度与正态分布概率密度最接近,高空风场条件风速的概率分布可近似假设为正态分布。综合以上工作,给出了在飞行器不确定性设计中考虑条件风速不确定性时,生成随机样本方法的选择建议。     

某轮式装甲车辆悬架系统改进及其仿真

某轮式装甲车辆悬架系统缓和、衰减冲击效果不佳,影响车辆战术性能发挥。提出了简单有效的改进方案,并应用AMESim软件对悬架原系统与改进系统进行了建模仿真。通过仿真结果分析,验证了改进方案的可行性。为装备的技术改造提供了一个简单有效的可选方案。     

排烟口设计对排烟效果影响的研究

排烟口是火灾发生时烟气排出的出口,排烟口高度和位置对排烟效果具有重要影响。运用FDS数值模拟方法,以实验台为依据建立数值模型,针对排烟口高度和排烟口位置的改变对排烟效果的影响进行分析,结果表明:随着排烟口高度的升高,各种排烟风速下的排烟效果都得到了改善。在排烟口风速较高的情况下,排烟口的高度变化对烟气溢出厚度的影响更大,采用大风速的控烟效果要优于小风速。侧排方式的排烟效果低于顶排方式,远壁排烟方式要优于近壁排烟方式。     

军事及武器系统发展的PSI战略

本文提出了系统通过逐渐的有计划的改进,以适应系统面临的威胁、技术、任务不断变化的需求的PSI战略;论述了系统可改进性理论(PSI)的基本原理;分析了RSI战略在军事系统中将发挥的重要作用;并建议在国防科工委系统推动PSI战略的应用与研究。     

一种改进AHP方法及其在C3I系统效能分析中的应用

针对Satty教授提出的传统AHP方法在实际应用中存在的缺陷,给出了标度改进的合理性原则,并基于该原则提出了标度改进的方法、改进权值的计算原理及计算方法。运用改进AHP方法,对防空C3I系统的效能度量进行了定量分析和计算。结果表明该方法易于理解和计算,适用于系统分析和系统评价。     

机械加压送风防烟设施探讨

阐述了建筑物机械加压送风防烟设施设置部位,讨论了几种特殊情况,对比压差法和风速法送风量计算存在的主要问题,指出风速法开门数量应取4个,建议送风机出口设置压力调节阀,以确保压差值满足规范要求.     

Putin – the masked nemesis of the strategy of ambiguity

Recent events demonstrate the complex and adaptive approach employed by Russia to reassert influence in Europe. The changing face of Russia’s strategy commenced in 2007 when it launched a crippling cyber-attack against Estonia. This was followed by a large Russian conventional attack against Georgia in 2008, occupying two large areas of the nation. 2014 witnessed the Russian annexation of Crimea where in just a week, Russia seized control of Crimea “without firing a shot.” The annexation of Crimea was rapidly followed by a Russian inspired and led subversive war in eastern Ukraine. The common thread among these diverse Russian operations is its use of ambiguity to confound and confuse decision makers in the West.     

India's counter-insurgency experience: the ‘trust and nurture’ strategy

The Indian Army, a force trained primarily for conventional warfare, has been engaged in internal counter-insurgency operations since the 1950s. Despite such a long innings on a counter-insurgency mode, little attention has been accorded within military circles to doctrinal innovation for waging sub-conventional warfare in India's democratic political context. At best, the Army continues to view counter-insurgency duty as secondary to its primary duty of defending India from external conventional threats. By conceptualizing a counter-insurgency strategy of ‘trust and nurture’, this article aims to fill this critical doctrinal gap in India's military policy. The author argues that a counter-insurgency strategy of ‘trust and nurture’ based on democratic political culture, measured military methods, special counter-insurgency forces, local social and cultural awareness and an integrative nation-building approach will result in positive handling of India's internal security problems. The author utilizes India's counter-insurgency experiences in Assam, Mizoram, Nagaland, Punjab, and Operation ‘Sadhbhavana’ in Jammu and Kashmir as illustrative empirical indicants in order to validate the ‘trust and nurture’ strategy.     

An Unlikely Alliance: Portuguese and South African Airpower in Angola, 1968–1974

The war that Portugal was obliged to fight in Africa began in 1961 and immediately stretched the resources of its armed forces. Nowhere was this thinness more apparent than in policing the vast territory of Angola. The east and southeast of Angola were particularly vulnerable, as the area was a vast, sparsely populated region characterised by enormous featureless plains or chanas covered in tall grass and broken by an extensive river system and mountainous forests. The only military solution to policing these immense spaces was aviation and specifically the helicopter that could carry troops into battle, protect them with a gunship and bring them home when the operation was concluded. The immediate problem for the Portuguese Air Force (Força Aérea Portuguesa or FAP) in Angola and elsewhere was a scarcity of helicopters. The solution was an alliance with South Africa, which had a strong inventory of Alouette IIIs, to help in policing the east. This move was likewise in the interest of South Africa, as its threat came from Zambia through south-eastern Angola. This article examines the strategic and tactical development of this unusual, cross-cultural alliance and the symbiotic relationship that resulted in destruction of the enemies of both in Angola.     

Helping hands: civil–military cooperation and Italy's military operation abroad

In the Post-Bipolar Era the growing complexity of the military operations requires a new approach for the resolution of international crises. Since the end of the Cold War, peace support operations (PSO) have become the mainstay and principal occupation of most Western armies. At the same time, Italy has been one of the most important actors in such an area. The article focuses on the cooperation between military and civil components (a process called CIMIC) as a key variable in the Italian PSOs. We will analyse in detail the main lessons learned from past military interventions as well as the general context in which new tendencies are taking place. The maintaining of a minimum security frame becomes essential to fulfil activities ‘collateral’ to the mission: reconstructing services and infrastructure, food distribution, water and medication, law and order, de-mining, training of local forces, and supporting local institutions. These are the main tasks to obtain thrust and support from the population.     

Terrorism,insurgency, kidnapping,and security in Africa's energy sector

Energy continues to serve as the bedrock of modern economies and the main driver of modern society. For Africa, the production and supply of energy resources such as crude oil, natural gas, uranium, coal, biomass, biofuels and other renewables are an important source of employment, rents, taxes, royalties and profits. This sector brings in several tens of billions of dollars of revenue annually. The production and delivery of such resources, however, depend on critical infrastructures such as pipelines, refineries, processing plants, terminals, rigs, electrical energy pylons, substations, pump stations, vessels, and tankers. These infrastructures have been attacked by terrorists, insurgents, vandals and saboteurs, all of whom see them as targets against which to register their grievances and extract concessions from the state. This paper is a chronological account of some of the documented incidents of terrorism, insurgency, kidnapping, destruction, sabotage, and human casualties suffered in the oil and gas sectors in Africa between 1999 and 2012. It is based on data extracted from the databases of the RAND Database of World Terrorism Incidents and the University of Maryland's Global Terrorism Database (GTD).     

国内外结构钢焊条研究的现状与发展

本文主要介绍了国外焊条的现状和发展趋势,包括焊条的高韧性、高效率、低尘低毒和耐吸潮性能,为国内的焊条研究提供了参考依据。     

A Sign of Victory?: ‘Scottish Swords’ and Other Weapons in the Possession of the ‘Auld Innemie’

Many late medieval documents, notably inventories of arms and armour, of Englishmen contain references to ‘Scottish swords’ and other weapons. What did the compilers of these documents mean when they described a weapon as ‘Scottish’? How did such weapons come to be in the possession of these men? This article will attempt to explain this phenomenon drawing on primary documentary sources and surviving material culture from Glasgow Museums’ collections and others, as well as artworks from the period.     

Tacit support for terrorism: The rapprochement between the USSR and Palestinian guerrilla organizations following the 1967 war

This article demonstrates the inconsistent and wavering Soviet attitude towards national liberation movements in general and the Palestinian organizations in particular. Until the late 1960s, the Soviets viewed these organizations with suspicion, hesitating to engage in political dialogue with them. However, in the 1970s, political and military events in the region, as well as modifications in the Kremlin's Cold War strategies, led to a general shift towards the Middle East in Soviet foreign policy. Soviet leaders showed increased willingness to provide certain Palestinian organizations with arms with which to conduct terrorist activities against Israeli, pro-Israeli, Jewish and Western targets. The article explores the complex relations between Palestinian organizations and the USSR in the field of international terror. The study also exposes and analyzes the nature and content of Soviet–Palestinian arms dialogues and transactions. It provides clear evidence that Soviet policymakers and other luminaries were fully informed of, and sometimes directly involved in, these transactions and dialogues at the highest levels.     

A1 Qaeda and the radical Islamic challenge to western strategy

The September 11 global crisis prompted by the attacks on the World Trade Center and the Pentagon raises major questions concerning the nature and trajectory of terrorism in the post-Cold War global order. Hitherto, terrorism has been largely debated by analysts at the level of nation states. Terrorist and insurgent movements have also been largely anchored in nationalist and ethnic power bases even when they have sought to mobilise a transnational ideological appeal on religious or class grounds. There have been a few exceptions to this pattern such as the alliance between the German Baader-Meinhof group and the Japanese Red Army Faction, but even such international alliances as this did not, until at least the 1980s, presage anything like a global terrorist network necessitating a global strategic response. This study examines terrorism and global strategic responses.