Impact of atmospheric turbulence on coherent beam combining for laser weapon systems

The performance of a laser weapon system based on coherent beam combining (CBC) depends on its propagation properties in the atmosphere. In this study, an analytical model based on partial coherent beam combining (PCBC) for assumed coherence coefficients between beams in a CBC lattice was developed. The Kolmogorov model of atmospheric turbulence and the Hufnagel-Valley model of Cn2 dependence on atmospheric parameters were implemented. Novel simplified metrics were proposed to assess the CBC performance. Several beam profiles (super-Gaussian, truncated Gaussian, etc.) and ge-ometries were analyzed in terms of maximal intensity in the far field. An approximate formula for PCBC efficiency dependent on the Fried radius was proposed. The results of CBC modeling were compared to those of the Gaussian beam propagation model in a turbulent atmosphere. The dependence of CBC performance on the Cn2 parameter, range, and elevation angle was analyzed. It could be concluded that the application of CBC for medium and long range propagation is impractical without an effective adaptive optics system.     

Damage to aircraft composite structures caused by directed energy system: A literature review

This paper presents a comprehensive review of the research studies on direct energy system effect on aircraft composite structures to develop a good understanding of state-of-the-art research and devel-opment in this area. The review begins with the application of composite materials in the aircraft structures and highlights their particular areas of application and limitations. An overview of directed energy system is given. Some of the commonly used systems in this category are discussed and the working principles of laser energy systems are described. The experimental and numerical studies re-ported regarding the aircraft composite structures subject to the effect of directed energy systems, especially the laser systems are reviewed in detail. In particularly, the general effects of laser systems and the relevant damage mechanisms against the composite structures are reported. The review draws attention to the recent research and findings in this field and is expected to guide engineers/researchers in future theoretical, numerical, and experimental studies.     

今天和明天的潜艇作战系统

今天典型的作战系统综合了潜艇上所有的传感器系统和武器系统。主要传感器设备通常由许多声呐系统构成,包括中频被动声呐、低频被动声纳和被动测距声呐。除声呐系统外,综合到作战系统的还有两个潜望镜、ESM接收机、各种电罗经和计程仪以及无线电导航辅助的导航系统和导航雷达。 目前潜艇上的主要武器是线导鱼雷,某些艇上还载有导弹。作战系统的典型功能包括传感器综合、决策/咨询支持以及武器使用。     

美高度关注中国高超音速武器研发

美国五角大楼称,中国军队上周首次试射了一种新型高超音速滑翔飞行器,该飞行器能够携带弹头突破美国导弹防御系统。此次试射表明,中国的战略核和常规武器建设取得了重大进展。美国军方发言人则表示,     

三封来信促整改 凝心聚力结硕果

正六月的树,葱葱郁郁,闪着绿色的光芒;六月的花,生机勃勃,浸润盛夏的希望;六月的风,柔和温馨,吹来沃野的清香;六月的雨,缠绵多情,挥洒丰收的印象。6月9日,记者迎着一阵阵扑面而来的热浪,来到距离博乐市以东40公里的五师八十一团。树木茂盛,鲜花盛开,芳草碧绿,俨然一帧花红叶茂的水墨长卷绵延于六月的天地之间。在八十一团广场的树荫下,职工李翠兰等人正在休息乘凉,当记者上前问及"三封信"时,他们皆点头示意了解此事。     

年轻干部应主动修炼定力

所谓“定力”,就是一个人在动态环境中要有稳定自己心态、稳定自己行为、干好本职工作的能力。简言之,就是定心定行之力。也可以有另一种解释,即一个人在工作和生活中所表现出来的不为繁杂现象所惑,坚忍不拔、执着追求的个性与品格。通俗地讲,就是使自己聚精会神专一做事的力量。     

2011年度美国参谋长联席会议主席指南

美国参谋长联席会议主席指南是指导联合参谋部工作和联合部队建设的年度文件.2011年度指南提出的优先任务与战略目标有3个:在大中东和中南亚捍卫美国的重要国家利益,改善部队的健康问题,平衡全球战略风险.指南还提出确保联合部队执行新的、废止"不问,不说"的政策,确保整个废止过程有序引导,保持部队的战备.