基于深度学习的目标跟踪技术及其多波段应用研究

目标跟踪是计算机视觉领域中最具挑战性的领域之一。首先，回顾了目标跟踪技术发展现状并总结出目标跟踪的一般流程；其次，分析了卡尔曼滤波、粒子滤波等传统目标跟踪方法的优缺点；再次，依次重点介绍了固定窗跟踪等相关滤波目标跟踪方法，以及全网络自适应目标跟踪等高性能目标跟踪方法；最后，总结了目标跟踪在红外、毫米波、太赫兹等波段的应用，并对多波段融合目标跟踪进行了展望。     

表面组装技术的应用与发展（下）

本文主要对表面组装技术的特点、表面组装工艺和表面组装技术的现状及发展趋势进行了全面的介绍，并分析了贴片机、网板印刷机、回流焊、波峰焊对表面组装工艺的影响。     

蜡纸存贮法在高超声速脉冲风洞舵-锥干扰流场显示中的应用

简述了蜡纸存贮法在高超声速脉冲风洞锥—舵干扰流场显示中的应用，给出了迎风面内舵周围干扰区立体和平面展开两种油流谱图，揭示了其三维干扰流动的特征。     

Critical phenomenon,crisis and transition to spatiotemporal chaos in plasmas

In a driven/damped drift-wave system a steady wave induces nonlinear variation of the dispersion of a perturbation wave (PW). Competition between the nonlinear dispersion with self-nonlinearity of the PW results in rich wave dynamic behaviors. In particular, a steady wave at the negative tangency slope of a hysteresis becomes unstable due to a saddle instability. It is found that such saddle steady wave (SSW) plays an important role in the discontinuous transition from a spatially coherent state to spatiotemporal chaos (STC). The transition is caused by a crisis due to a collision of the PW attactor to an unstable orbit of the SSW. In the time evolution, it is a ‘pattern resonance’ of the realized wave with the virtual SSW that triggers the crisis. The transition also displays as a critical phenomenon in parameter space, which is related to the change in the symmetry property of the motion of master mode (k = 1) of the PW with respect to that of SSW. In the spatially coherent state the former is trapped by the SSW partial wave, while in the STC it can become free from the latter, its trajectory crosses two unstable orbits of the SSW frequently, causing very turbulent behavior. This revised version was published online in August 2006 with corrections to the Cover Date.     

带减阻杆高超声速飞行器外形气动特性研究

采用高超声速风洞测力试验方法测量钝头飞行器头部减阻杆的高超声速气动特性,研究减阻杆的气动减阻原理,分析了多组不同构型减阻杆的减阻效果。结果表明,减阻杆显著减少了钝头飞行器高超声速的阻力,最大的减阻率达到60％之多;减阻效果与减阻杆构型和迎角状态密切相关;减阻杆会诱发稳定性、“热斑”以及非定常脉动等不利问题。     

基于叶尖定时技术分析叶片非整阶次振动

介绍了非接触叶尖定时技术分析航空发动机转子叶片非整阶次振动,通过数值仿真结果与实测结果对比,验证了相关分析方法可有效的分析叶片非整阶次振动。详细介绍了某发动机台架试车转子叶片非整阶次振动测量实例。     

基于LES方法的平板非定常激波/湍流边界层干扰研究

以高超声速发动机进气道湍流分离控制为应用背景,采用大涡模拟(LES)方法进行马赫数为3.0(唇口附近马赫数约为3.0)的激波/湍流边界层干扰(SWTBLI)流场机理研究.利用扰动循环引入的方法,先得到充分发展湍流场,然后根据斜激波关系式引入激波的方法进行激波/湍流干扰模拟.研究结果显示:充分发展湍流场在激波作用下产生逆...     

轴的扭转振动分析

用波方程描述轴的扭转振动，轴的振劝用空间与时间坐标来描述的，运动方程是偏微分方程。     

多层太阳大气模式中Alfven波的传播

将实际的太阳大气划分为多个等温层次，导出了均匀倾斜磁场下线性Alfven波通过任意多等温层的能量透射率，结果表明，两等温层模式与三等温层模式的结果存在本质的区别。在两等温层中，温度的跃变式增高对Alfven波起着高通滤波的作用，而三等温层中在高频端Alfven波的透射率显示为振荡形态，对实际大气温度模式的计算结果表明，太阳低层大气更适合于周期为数秒的Alfven波的能量传输。     

Scaling of interaction lengths for hypersonic shock wave/turbulent boundary layer interactions

The interaction length induced by Shock Wave/Turbulent Boundary-Layer Interactions (SWTBLIs) in the hypersonic flow was investigated using a scaling analysis, in which the interaction length normalized by the displacement thickness of boundary layer was correlated with a corrected non-dimensional separation criterion across the interaction after accounting for the wall temperature effects. A large number of hypersonic SWTBLIs were compiled to examine the scaling analysis over a wide range of Mach numbers, Reynolds numbers, and wall temperatures. The results indicate that the hypersonic SWTBLIs with low Reynolds numbers collapse on the supersonic SWTBLIs, while the hypersonic cases with high Reynolds numbers show a more rapid growth of the interaction length than that with low Reynolds numbers. Thus, two scaling relationships are identified according to different Reynolds numbers for the hypersonic SWTBLIs. The scaling analysis provides valuable guidelines for engineering prediction of the interaction length, and thus, enriches the knowledge of hypersonic SWTBLIs.