排序方式: 共有164条查询结果,搜索用时 0 毫秒
61.
小水线面四体船的阻力特点分析 总被引:2,自引:1,他引:1
从粘性阻力、兴波阻力和旋涡阻力3个方面分析小水线面四体船(以SLICE为代表)的阻力特点,讨论了浮体横向错位、支柱和潜体形状、航速和吃水对兴波阻力的影响.结果表明,在浅水中一定航速范围内,与等排水量的小水线面双体船(SWATH)相比,SLICE有一定优势. 相似文献
62.
为了研究尾流模拟火箭弹的空中弹道特性对模拟尾流区域的影响,建立火箭弹质点外弹道模型、阻力板和发动机空间运动微分方程以及连接绳的受力模型,得到火箭弹无控飞行、空中转向、空中分离至爆索展开入水全过程的空间运动微分方程。对尾流模拟火箭弹全程弹道进行仿真分析,着重分析不同初始射击诸元对爆索空中弹道的影响,探究初始发射角、脉冲发动机的喷管数量、点火时间以及火箭弹空中分离时间对模拟尾流生成区域的影响。仿真结果表明:初始发射角为15°时火箭弹射程和最大射高相对比较合理;火箭弹空中转向角度依赖于脉冲发动机总冲量,与点火时刻无关;空中分离时刻对爆索入水发泡区域影响不太明显,在满足转向要求和发泡区域要求的情况下应该尽早完成空中转向和分离。 相似文献
63.
Jonathan Colman 《战略研究杂志》2013,36(2):285-307
The article explores the 1950 ‘Ambassador's Agreement’ (named after US Ambassador Lewis Douglas) about establishing long-term US air bases in the UK. During the discussions British representatives expressed resentment of American pressure and were concerned about the expense that developing the bases for American purposes might entail. There were even fears that Washington might use the airfields to launch an atomic bomb attack on the USSR without regard to the views of the UK government. The British consented to providing the bases because they wanted to enmesh the US further in UK and Western European defence. For their part American negotiators had wanted to further US atomic strategy without delay. Although the agreement imposed no restriction on the use of the airfields, some US officials believed that in a crisis the UK government might try to prevent them being used for atomic bombing missions. 相似文献
64.
Douglas Porch 《Small Wars & Insurgencies》2013,24(2):239-257
Counterinsurgency (COIN) has again emerged as a topic of both contemporary and historical interest in the age of what has been called a global counterinsurgency. However, little attention is being paid to the historical lineage of a COIN doctrine that is being rediscovered and promoted by an enthusiastic group of military intellectuals and commanders as the basis for US Army and Marine Corps doctrine. This article argues that historical claims for COIN success, based on courting popular gratitude by improving economic conditions, are at best anchored in selective historical memory, when not fantasy fabrications. The first argument of this article is that COIN does not constitute a distinct form of warfare, but merely a sub-set of minor tactics. Second, ‘hearts and minds’, so-called population-centric warfare, has seldom been a recipe for lasting stability. Rather, historically counterinsurgency succeeded when it has shattered and divided societies by severely disrupting civilian life. In fact, COIN is a nineteenth century legacy of empire whose uniqueness and impact was mythologized in its own day, and that is unlikely to prove a formula for strategic success in the twenty-first century. 相似文献
65.
66.
设计了一种目标凝视自适应姿态控制方法,可以实现未知目标位置和未标定相机参数条件下的目标凝视控制。根据运动学方程提取出恰当的未知参数,从而将参数进行线性化表示;引入关于未知参数的势函数,确保参数矩阵的秩满足稳定性要求;采用了一个参数自更新律在线估计未知参数,提出了基于估计参数的自适应控制律。采用李雅普诺夫稳定性理论和芭芭拉特引理,证明了目标成像位置与期望成像位置的误差可以渐近收敛到零。仿真结果表明:目标位置未知且相机参数存在偏差的情况下,该自适应控制器能〖BHDWG8,WK10YQ,DK1*2,WK1*2D〗〖XCSC.TIF;%129%129〗听语音 聊科研与作者互动 够有效地对深空目标进行凝视观测。 相似文献
67.
68.
69.
Martin Rink 《Small Wars & Insurgencies》2014,25(4):828-842
In the Age of Napoleon, ‘small wars’ and ‘revolutionary war’ were closely connected. There were, however, different strands of this phenomenon: speaking professionally, conservative officers condemned small wars as an irregular regression to previous less disciplined forms of warfare. The Prussian state continually tried to discipline and regulate spontaneous risings. Yet the irregular character of small wars offered the opportunities for a less complex way of fighting, thus enabling the arming of the ‘people’ to fight. Individual undertakings, such as Ferdinand von Schill's doomed campaign in 1809, were designed to spark off a general popular uprising. But they were cheered by many and supported by few. Meanwhile, Neidhardt von Gneisenau conceived guerrilla-style Landsturm home-defence forces, which were designed for an irregular people's war. These concepts were put into practice in the ‘war of freedom’ – or ‘war of liberation’ – in 1813. Eventually both the mobilisation and the tactics remained regular, however, despite the emphatic appeal to a national ‘people's war’. 相似文献
70.
面向脉冲压缩雷达的灵巧噪声干扰方法研究与仿真分析 总被引:2,自引:0,他引:2
针对脉冲压缩雷达,研究了基于卷积调制、乘积调制的灵巧噪声干扰仿真分析方法。该方法基于数字射频存储(DRFM)技术,将干扰机接收并存储的雷达发射信号与噪声信号进行卷积、乘积调制后转发出去,为干扰信号的产生提供了有效途径。仿真实验证明该方法能有效干扰脉冲压缩雷达,同时具有压制性干扰和欺骗性干扰的效果。 相似文献