An air cavity method for increasing the underwater acoustic targets strength of corner reflector

In order to improve the underwater acoustic target strength of corner reflectors, according to the principle of acoustic impedance mismatch of the boundary layer, the method of using air cavity to increase the underwater acoustic target strength of corner reflectors is proposed. The acoustic reflection coefficients of underwater air layer and single layer metal sheet are calculated and compared. The results show that the reflection coefficient of single layer metal sheet is greatly affected by frequency and incidence angle, and the reflection coefficient of air layer in water is large and little affected by frequency and incidence angle. On this basis, a new kind of airfilled cavity corner reflector is designed. The acoustic scattering characteristics of underwater airfilled cavity corner reflector are calculated cumulatively, and the results are compared with the monolayer metal sheet corner reflector. The simulation results show that the acoustic reflection effect of the airfilled cavity corner reflector is better. In order to verify the correctness of the method, the test was carried out in the silencing tank. The experimental results show that the simulation results are in good agreement with the experimental results, and the airfilled cavity can improve on acoustic reflection performance of the underwater corner reflector.     

吸气式远程超声速防空导弹一体化外形设计的几个重大技术问题

根据国外吸气式超声速战术导弹一体化外形设计取得的最新进展 ,着重分析了这类导弹外形设计的特点和技术关键 ,提出了吸气式远程超声速防空导弹一体化外形设计中应解决好的几个重大技术问题 ,以期引起各方对吸气式防空导弹总体设计中有关问题的关注和讨论 ,共同寻找解决这些技术问题的有效途径     

Peacetime military innovation through inter-service cooperation: The unique case of the U.S. Air Force and Battlefield Air Interdiction

ABSTRACT

Military doctrine assures a nation’s survival. Yet even when faced with a security threat that requires change, militaries rarely innovate but instead adhere to old doctrines that enhance autonomy, reduce uncertainty and claim resources. Existing theories cannot explain an important case of peacetime military innovation when the U.S. Air Force adopted Battlefield Air Interdiction to support the Army’s AirLand Battle doctrine. A revised theory of peacetime military innovation through inter-service cooperation resulting from external and internal threats explains not only why innovation occurred with Battlefield Air Interdiction but also why such successful cases are so rare.     

无人机对未来防空作战的影响及对策研究

未来防空战场中,无人机已成为一种重要的空中威胁。阐述了无人机的现实威胁,分析了无人机对防空作战的影响,探讨了抗击无人机的对策及措施。     

从美国三大主力战斗机发展看战斗机的发展动向

以美国 2 1世纪列装的三大主力战斗机为背景 ,介绍了主力战斗机的研制情况 ,并对战斗机发展动向作了分析 ,指出以战斗机为主的飞机机群仍将是防空体系的主要威胁之一。     

防空导弹武器装备备件优化模型

根据防空导弹武器装备使用保障的特点 ,确定了影响备件配置的主要因素。采用装备战备可靠度和经济因素相结合的方法 ,研究并提出了备件优化模型。最后就其实际应用作了说明 ,以便于在实际装备中采用。