Prospects of using a permanent magnetic end effector to despin and detumble an uncooperative target

Space debris, such as defunct satellites and upper stages of rockets, becomes an uncooperative target after losing its attitude control and communication ability. In addition, tumbling motion can occur due to environmental perturbations and residual angular momentum prior to the object’s end-of-mission. To minimize the collision risk during docking and capturing of the tumbling target, a non-contact method based on the eddy current effect is put forward to transmit the control torque to the tumbling target. The main idea is to induce a controllable torque on the conducting surface of the tumbling target using a rotational magnetic field generated by a Halbach rotor. The radial and axial Halbach rotors are used to damp the spinning and nutation motions of the target, respectively. The normal and tangential force are evaluated concerning the relative pose between the chaser and the target. A simplified dynamic model of the nutation damping and despinning processes is developed and the influences of the asymmetrical principal moments of inertia and transverse angular velocity are discussed. The numerical simulation results show that the designed Halbach rotor stabilized the target attitude within an acceptable time. The electromagnetic nutation damping and despinning method provides new solutions for the development of on-orbit capture technology.     

复杂群塔风荷载试验研究

介绍了一复杂群塔结构节段刚性测压试验概况和主要试验结果,讨论了结构典型部位风压分布的基本特征和结构风压分布的基本规律.试验结果表明,由于该结构由多个单体高耸塔结构组成,相互干扰严重,风压的分布相当复杂.根据风压试验结果得到了风力沿各塔高度的分布,并讨论了分布规律,进一步得出基底剪力系数和基底弯矩系数,分析了最危险风向,给出了用于结构设计的荷载建议.     

星用非金属材料出气物成分及污染光学测试分析

文章利用新研制的分子污染出气物成分检测分析设备,对空间辐射致冷器用的几种星用非金属材料的出气污染物进行测试,分析鉴定材料出气物的成分,确定材料在真空烘烤过程中观察到的各种物质源。利用试验获得的材料出气污染物对光学参数的影响数据,并结合光学效应试验研究结果,进一步得到材料出气引起透镜光学参数变化的结果,为型号设计师提供直接的污染控制依据。     

旋转式战术导弹马格努斯效应的实验研究

本文介绍了旋转弹在低速风洞中 Magnus 效应的实验研究结果。通过不同组合体的实验,如光弹,“一”字型前翼+强身,弹身+“十”字型尾翼,“一”字型前翼+弹身+“十”字型尾翼,分别研究了旋转对弹纵向气动特性的影响及弹的 Magnus 效应特性。     

双天线对旁瓣匿影雷达相参干扰的应用技术

双天线干扰体制是一部干扰机采用两部干扰天线同时对目标实施干扰，可以实现对旁瓣匿影雷达的干扰。重点研究采用双天线相参干扰对抗旁瓣匿影雷达的方法，分析了干扰效果。计算和仿真的结果表明当干扰对准雷达主瓣方向的偏角不大于10°，两天线相距大于500m时对雷达有显著的（压制性的）干扰效果。     

Effect of evaporation and solutocapillary-driven flow upon motion and resultant deposition of suspended particles in volatile droplet on solid substrate

Particle motion in a volatile droplet on a solid surface, especially the behavior of particles depositing in the vicinity of a solid–liquid–gas boundary line (contact line) is focused. This phenomenon is called the ‘coffee stain problem’. Motion and deposition of the particles suspended in distilled water droplets and distilled water–ethanol mixture droplets are discussed. The spatio-temporal particle motion is analyzed by the three-dimensional particle tracking velocimetry (3D PTV). A discussion of the morphology of the particles stuck to the solid surface after the dryout of the droplet is also given.     

武汉城市圈建设中的产业政策选择——从产业集聚效应的角度分析

武汉城市圈虽然城市密集，基础较好，但是城市圈内各城市间没有形成良好的分工合作，产业低水平重复，资源配置效率低下。通过运用计量经济学工具，建立集聚经济的分析框架，测算武汉城市圈内各城市的产业集聚效应，来探讨武汉城市圈建设中的产业政策选择问题。通过分析我们发现，在武汉城市圈中，黄冈市、成宁市和天门市不适合优先发展工业．因此未来要增强自身经济集聚能力，加快经济发展速度，与武汉城市圈整体发展水平相协调；武汉市和仙桃市适合优先发展轻工业；黄石市、鄂州市、孝感市和潜江市适合优先发展重工业。     

Aeroelastic effect on aerothermoacoustic response of metallic panels in supersonic flow

A finite element formulation is presented for the analysis of the aeroelastic effect on the aerothermoacoustic response of metallic panels in supersonic flow. The first-order shear deforma-tion theory (FSDT) and the von Karman nonlinear strain-displacement relationships are employed to consider the geometric nonlinearity induced by large deflections. The piston theory and the Gaus-sian white noise are used to simulate the mean flow aerodynamics and the turbulence from the boundary layer. The thermal loading is assumed to be steady and uniformly distributed, and the material properties are assumed to be temperature independent. The governing equations of motion are firstly formulated in structural node degrees of freedom by using the principle of virtual work, and then transformed and reduced to a set of coupled nonlinear Duffing oscillators in modal coor-dinates. The dynamic response of a panel is obtained by the Runge-Kutta integration method. The results indicate that the increasing aeroelastic effect can lead the panel vibration from a random motion to a highly ordered motion in the fashion of diffused limit cycle oscillations (LCOs), and remarkably alter the stochastic bifurcation and the spectrum of the aerothermoacoustic response. On the other hand there exists a counterbalance mechanism between the external random loading and the aeroelastic effect, which mainly functions through the nonlinear frequency-amplitude response. It is surmised that the aeroelastic effect must be considered in sonic fatigue analysis for panel structures in supersonic flow.     

正确理解光电效应中的阈能

本简要叙述了光电效应产生的微观机理，用反证法证明了光子与自由电子之间不能发生光电效应，从而说明了影响光电效应截面的因素，指出电子的束缚能越大，光电效应截面就越大，并指出阈能只具有统计意义。     

一种分数间隔解相关修正判决反馈盲均衡算法研究

以消除多径效应对传输信号的影响、提高信号传输的效率为背景,在介绍基于CMA算法的判决反馈盲均衡算法(DFE算法)的基础上,提出了改进的分数间隔判决反馈盲均衡算法。通过实验仿真结果的分析表明,改进方法在收敛速度、剩余误差等方面取得明显改善,具有一定的实际应用价值。