基于转盘爬虫法的雷达地形遮蔽盲区快速计算

为解决飞机在低空突防过程中的雷达地形遮蔽盲区快速计算问题,提出了一种基于转盘爬虫对象的快速算法。首先介绍了雷达盲区产生的因素,分析了地形遮蔽和地球曲率盲区的计算模型,然后定义了转盘及爬虫对象,并设计了基于转盘爬虫对象的地形遮蔽盲区计算方法和流程。在此基础上,将雷达地形遮蔽盲区计算结果进行三维建模及可视化,通过典型算例对算法进行对比测试和实验,得到不同高度的雷达地形遮蔽盲区分布图及三维可视化模型,证明了算法的快速性和可行性。     

Influence of thickness and projectile shape on penetration resistance of the compliant composite

The present study deals with development of conceptual proof for jute rubber basedflexible composite block to completely arrest the projectile impacting the target at high velocity impact of 400 m/s through numerical simulation approach using finite element (FE) method. The proposed flexible composite blocks of repeating jute/rubber/jute (JRJ) units are modelled with varying thickness from 30 mm to 120 mm in increments of 30 mm and impacted by flat (F), ogival (O) and hemispherical (HS) shaped projectiles. All the considered projectiles are impacted with proposed flexible composite blocks of different thicknesses and the penetration behaviour of the projectile in each case is studied. The penetration depth of the projectile in case of partially penetrated cases are considered and the effect of thickness and projectile shape on percentage of penetration depth is statistically analyzed using Tagu-chi's design of experiments (DOE). Results reveal that the though proposedflexible composite block with thickness of 90 mm is just sufficient to arrest the complete penetration of the projectile, considering the safety issues, it is recommended to use theflexible composite with thickness of 120 mm. The nature of damage caused by the projectile in the flexible composite is also studied. Statistical studies show that thickness of the block plays a prominent role in determining the damage resistance of the flexible composite.     

几种防锈液对T52钢在酸性介质中耐蚀性的影响

研究了几种防锈液对T52(10Ti热)钢在Ph=5.0酸性水溶液中耐蚀性能的影响.用线性极化和交流阻抗法对这些防锈液的耐蚀性能进行了综合评估,试验结果表明:亚硝酸钠类、含氨基和羧基的有机化合物类两种防锈液的耐蚀性能较好;并用动电位扫描法对上述防锈液的作用机理进行了初步探讨,试验表明:上述防锈液主要是抑制电极的阳极过程.     

线型数据通道高层综合的运算单元优化分配算法

运算单元分配是高层综合的关键算法之一。采用了一种面向数字信号处理应用、规则的线型数据通道模型,其中心思想是全局互联的最小化。以最小着色算法构造的一个初始分配为起点,采用随机进化算法对其进行迭代改善,以减小数据寄存器数和运算单元之间的数据交换。最后还给出了典型实例的实验结果。     

低阶高精度单元的发展

综述了四节点等参单元存在的问题，以及提高其精度的途径，并对这些方法略做评述，且探讨了发展高精度单元的方法。     

利用2006-2012年北半球冬季无线电探空站及MACC再分析数据对COSMIC GPS RO 反演的水汽廓线进行质量分析

为了验证COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate, COSMIC) GPS (Global Positioning System, GPS) 掩星（Radio Occultation, RO）反演的水汽廓线的质量,同时也为了验证水汽对COSMIC GPS RO反演结果的影响,利用2006-2012年北半球冬季（12月、1月及2月）低纬度地区（30°S-30°N）无线电探空站数据及全球MACC再分析数据对1000 hpa-200 hpa 高度层的COSMIC GPS RO 反演的比湿廓线进行了精度和可靠性验证。这里分析了无线电探空比湿数据及MACC-Reanalysis数据相对于COSMIC GPS RO反演的比湿数据的相对误差在不同高度,不同比湿值的分布情况,发现在对流层中上层出现比湿相对误差极端值概率较大,在500 hpa -600 hpa高度层出现比湿相对误差极端值最大。在低纬度地区,无线电探空站比湿数据与COSMIC GPS RO反演的比湿数据之间的相对误差要小于20%,标准偏差也小于20%。通过统计比较低纬度地区及全球范围MACC再分析数据相对与COSMIC GPS RO数据的相对误差与标准偏差,发现低纬度地区COSMIC GPS RO 反演的比湿廓线精度要比全球范围要差,同时分析了两者之间的相对误差Re(q)在不同区间（-100%相似文献   

基于群体协同的驱护编队中近程防空的系统效能

针对中近程反导的具体要求,分析了典型的驱护编队反导模式下编群队形特点,研究了指挥舰与护卫舰的队形关联性,探讨了基于信息化作战模式的抗饱和攻击能力,建立了基于多目标优化的最保守与最乐观情况下的抗饱和攻击模型,得到舰艇编队协同防空的系统效能,对驱护编队防空反导指挥决策具有很强的参考价值。     

基于GA-ML-PMHT的多基站无源协同定位方法

针对无源协同定位系统中低可观测目标的航迹初始及维持问题,提出一种基于遗传算法的极大似然概率多假设的多基站无源协同定位方法。首先,建立多基站无源协同定位系统数学模型。其次,提出基于极大似然概率多假设的无源协同定位航迹初始算法,并首次利用遗传算法解决极大似然概率多假设中的优化求解问题,以提高目标检测跟踪性能。最后,通过滑窗法实现航迹维持。仿真结果表明,所提方法能够有效解决多基站无源协同定位系统中低可观测目标的航迹初始及维持问题。     

Resistance through Islamic clerics against Boko Haram in northern Nigeria

Islamic clerics and scholars constitute one of the community actors affected by the Boko Haram crisis in northern Nigeria. This group is also one that is most familiar with the essential doctrinal elements required to deconstruct the narrative pushed by Boko Haram in a crisis where ideology represents a vital aspect. While not undermining the bearing which socio-economic and political issues have on the crisis, this paper frames the focus to emphasise the long-term battle where Islamic clerics are involved in winning hearts and minds. Drawing upon fieldwork conducted in Sokoto State and Borno State, this paper highlights the influential role of clerics in communal mobilisation and resistance against Boko Haram. It is suggested that a deeper integration of this community actor into the broader counter-insurgency struggle in northern Nigeria would be beneficial.     

中小型客车用钢──水热管式采暖装置工作温度控制研究

讨论了影响热管工作温度ｔｖ的主要因素,提出了控制钢──水热管工作温度（采暖装置的工作温度）的管长参数的确定原则,介绍了用于客车上的实例。