排序方式: 共有43条查询结果,搜索用时 15 毫秒
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在横流理论和wardlaw集中涡法的基础上,通过采用一组合适的自由参数,用半经验半理论的方法计算了无安定器航弹在大攻角情况下的气动特性。计算过程中考虑了不同转速对力与力矩的影响,并对结果作出了分析。 相似文献
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When considering the bomb explosion damage effect, the air shock wave and high-speed fragments of the bomb case are two major threats. In experiments, the air shock wave was studied by the bare ex-plosives superseding the real cased bomb; in contrast, the bomb case influence was ignored to reduce risk. The air explosion simulations of the MK84 warhead with and without the case were conducted. The numerical simulation results showed that the bomb case significantly influenced the shock wave generated by the bomb: the spatial distribution of shock wave in the near field changed, and the peak value of shock wave was reduced. Breakage of the case and kinetic energy of the fragmentation consumed 3 and 38% of the explosion energy, respectively. The increasing factors of the peak over-pressure induced by the bare explosive on the ground and in the air were 1.43-3.04 and 1.37-1.57, respectively. Four typical stages of case breakage were defined. The mass distribution of the fragments follows the Mott distribution. The initial velocity distribution of the fragments agreed well with the Gurney equation. 相似文献
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Toshihiro Higuchi 《战略研究杂志》2013,36(1):83-116
The idea of ‘clean’ bombs, nuclear weapons with a reduced amount of radioactive fallout resulting from their fission part, has met much ridicule since its public inauguration in 1956. Many scholars have regarded the bombs as a propaganda tool, stopping short of analyzing their role in the transformative phase of US nuclear strategy in the 1950s. This paper reexamines the clean bomb episode through 1958, shedding light upon the dynamic relationship between the development of nuclear weapons technology and the evolution of nuclear strategy from massive retaliation to flexible response. It also discusses the mechanism and momentum of nuclear weapons technology innovation until the US suspended nuclear testing in late 1958. 相似文献
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In the aftermath of September 11, 2001 and Hurricane Katrina, the United States government has spent tens of billions of dollars to improve the nation's ability to respond to a natural disaster or terrorist attack, but the emphasis on immediate first response has left many long-term environmental, political, and technological challenges unaddressed. Although a dirty bomb attack is unlikely to yield the same amount of physical devastation and death as caused by Katrina or a nuclear weapon, the social, psychological, and economic impact would be enormous. At present, however, the United States lacks the technology necessary to decontaminate a large, densely populated urban area under time, political, and economic constraints. This article reviews past cleanup experiences and current decontamination capabilities to consider the long-term implications of a dirty bomb, identifies weaknesses in America's existing response capabilities, notes possible areas of political friction, and considers the implications of the failure to adequately prepare. Having the appropriate decontamination techniques established and long-term plans in place before an incident occurs will significantly improve the government's ability to protect public and environmental security, establish a viable decontamination strategy, allow residents to return to their homes, and get the local economy back on its feet. 相似文献
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Based on the first-person account of coauthor Pierre Billaud, a prominent French participant, this article describes for the first time in such detail the history of the development of the French hydrogen bomb in the 1960s and the organization of military nuclear research in France. The authors illustrate the extent to which French defense and governmental authorities did not support research on thermonuclear weapons until 1966. Billaud, a project insider, relates the historical episodes that led to France's successful 1968 thermonuclear test, including the names of the individuals involved and how a timely tip from a foreign source hastened the success of the first H-bomb test. 相似文献
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《防务技术》2014,10(2):106-110
Microcellular combustible objects for application of combustible case, caseless ammunition or combustible detonator-holding tubes are fabricated through one-step foaming process, in which supercritical CO2 is used as foaming agent. The formulations consist of inert polymer binder and ultra fine RDX. For the inner porous structures of microcellular combustible objects, the cell sizes present a unimodal or bimodal distribution by adjusting the foaming conditions. Closed bomb test is to investigate the influence of both porous structure style and RDX content on burning behavior. The sample with bimodal distribution of cell sizes burns faster than that with unimodal distribution, and the concentration of RDX can influence the burning characteristics in a positive manner. In addition, the translation of laminar burning to convective burning is determined by burning rate versus pressure curves of samples at two different loading densities, and the resulting transition pressure is 30 MPa. Moreover, the samples with bigger sample size present higher burning rate, resulting in providing deeper convective depth. Dynamic vivacity of samples is also studied. The results show that the vivacity increases with RDX content and varies with inner structure. 相似文献
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针对自导深弹自导系统设计过程中,面临的简化目标探测系统和弹体姿态控制系统的要求,设计采用自动调整提前角导引算法作为自导策略;操极限舵,采用直接由导引算法得出舵角值的弹体姿态控制方法.给出了纵平面内深弹运动学模型、目标运动学模型、深弹与目标相对运动模型的数学描述,并在Matlab/Simulink 环境下完成了以上三个模型的实现和子模块封装, 编制了描述深弹整个自导过程的Simulink模块化程序;给出了自导深弹自动调整提前角导引方法的实现原理,并基于Simulink/StateFlow工具箱建立了该导引算法的图形化程序进行了仿真研究,验证了导引方法的有效性. 相似文献