Electrochemical trepanning with uniform electrolyte flow around the entire blade profile

In the traditional machining process for diffusers, blades are easily deformed, and methods suffer from high tool wear and low efficiency. Electrochemical machining(ECM) possesses unique advantages when applied to these difficult-to-machine materials. In the ECM process, theflow field plays a crucial role. Here, an electrolyte flow mode that supplies uniform flow around the entire blade profile was adopted for electrochemical trepanning of diffusers. Various flow rates were employed to obtain the optimal flow field. Simulations were conducted using ANSYS software, and results indicated that increasing the flow rate substantially afforded a more uniform flowfield. A series of experiments was then performed, and results revealed that increasing the flow rate greatly improved both the machining efficiency and the surface quality of the diffusers. The maximum feeding rate of the cathode reached 4 mm/min, the blade taper of the concave part decreased to 0.02, and the blade roughness was reduced to 1.216 lm. The results of this study demonstrated the high feasibility of this method and its potential for machining other complex components for engineering applications.     

磁选态单束铯束管束光学参数的模拟计算和设计

为提高铯束管跃迁信号强度,在束光学参数设计中,用蒙特卡罗方法模拟计算铯原子通过率和未跃迁比例。通过改变模拟计算中的束光学参数,分析铯原子通过率、未跃迁比例和倍增器首极电流的变化趋势,得到了主要束光学参数的合理取值范围。在铯束管实际装配和试验中使用束光学参数设计结果,有效地增加了倍增器首极电流。     

表面介质阻挡放电对扩散火焰燃烧特性的影响

针对表面介质阻挡放电（SDBD）在激发等离子体时具有显著的气动效应和化学活化效应，为分析表面介质阻挡放电对空气/甲烷同轴剪切扩散燃烧的助燃效果，实验使用高频交流电源，基于等离子体诱导射流逆向激励对火焰施加控制。根据获取的射流流场纹影图像、火焰图像和CH*自发辐射，研究了等离子体对不同燃烧条件下火焰燃烧特性的影响。结果表明:受等离子体气动激励作用，火焰上游细长剪切层的空气/甲烷掺混得到增强，从而扩大了剪切层燃烧宽度，同时燃烧释热速率会明显提高，这主要与等离子体活化效应有关，并且该效应显著增强了位于喷嘴出口火焰基的燃烧强度。在空气流量较低时，等离子体气动激励可有效增大火焰下游湍流度和射流角，使火焰高度降低、宽度增大，且作用效果随放电电压提高逐渐增强。      

基于层次分析法的综合射频架构选取技术研究

综合射频系统是作战飞机航空电子系统的重要组成部分，它们是作战飞机通过无线电方式感知外界信息的重要系统。系统架构的选取直接影响了飞机的作战性能，针对以往架构选取依赖大量定性分析而缺乏定量对比问题，提出了基于层次分析法的综合射频架构选取技术，该技术能够有效地根据不同的任务需求和平台需求，综合考虑定量和定性因素，给出更为合理对比分析结果，为综合射频系统的系统设计提供技术支撑。该技术也可推广到航空领域其他多目标决策问题的应用。     

数字全息测量超高速撞击碎片云实验研究

在中国空气动力研究与发展中心(CARDC)超高速碰撞中心(HIRC)7.6 mm超高速碰撞设备的基础上，搭建纳秒级脉冲激光数字全息系统。提出滤波片和衰减片组合布置，减弱超高速碰撞等离子体自发光、提高信噪比的方法。实验获得了2.25 mm铝球弹丸以4.0 km/s的速度撞击0.5 mm厚铝板形成碎片云的全息图。采用小波变换算法对碎片云全息图进行重建，得到超高速撞击碎片云的三维结构和碎片大小。碎片云的轮廓呈椭球型，分为碎片云的前端、核心和外壳，碎片主要分布在弹丸破碎形成的碎片云核心，存在大碎片，且分布较集中，对后板的损伤也严重     

低速大转矩永磁游标电机在发酵罐中的应用

采用秸秆生产丁醇时,为了达到高效率发酵,需要使发酵液中菌体分布均匀,所加物料需要及时搅拌。工业化生产丁醇的发酵罐尺寸较大,搅拌过程对驱动电机的输出转矩要求较高,因此高效率、小体积、低速大转矩的秸秆发酵搅拌电机对工业化发酵生产丁醇意义重大。设计了一种定转子永磁游标电机用于发酵液搅拌,并对电机的槽极数、电磁性能进行了具体的研究。制造样机并采用滞环控制实现了对液态发酵对象的快速响应,且实现了低能耗、高效率的发酵过程。     

基于ANSYS Workbench的行星滚柱丝杠动态特性分析

通过Pro/Engineer建立行星滚柱丝杠三维模型，基于ANSYS Workbench有限元分析技术进行模态与谐响应分析，得到前六阶固有频率与各阶模态振型，确定共振频率，掌握对应频率下的位移峰值响应，并研究螺母处于不同工作位置时对固有频率的影响，为基于行星滚柱丝杠传动的舵系统抗振设计提供数据支撑。     

Real-time object tracking via least squares transformation in spatial and Fourier domains for unmanned aerial vehicles

This paper addresses the problem of real-time object tracking for unmanned aerial vehicles. We consider the task of object tracking as a classification problem. Training a good classifier always needs a huge number of samples, which is always time-consuming and not suitable for realtime applications. In this paper, we transform the large-scale least-squares problem in the spatial domain to a series of small-scale least-squares problems with constraints in the Fourier domain using the correlation filter technique. Then, this problem is efficiently solved by two stages. In the first stage, a fast method based on recursive least squares is used to solve the correlation filter problem without constraints in the Fourier domain. In the second stage, a weight matrix is constructed to prune the solution attained in the first stage to approach the constraints in the spatial domain. Then, the pruned classifier is used for tracking. To evaluate proposed tracker's performance, comprehensive experiments are conducted on challenging aerial sequences in the UAV123 dataset. Experimental results demonstrate that proposed approach achieves a state-ofthe-art tracking performance in aerial sequences and operates at a mean speed of beyond 40 frames/s. For further analysis of proposed tracker's robustness, extensive experiments are also performed on recent benchmarks OTB50, OTB100, and VOT2016.