无人机航迹规划技术研究及发展趋势

通过对无人机航迹规划的研究,构建了无人机航迹规划的结构框架;分析了无人机系统约束及威胁场约束,探讨了无人机航迹几何建模方法及规划算法的国内外研究概况;并着重分析了规划算法。最后,阐述了无人机航迹规划面临的关键问题及发展趋势。     

Synoptic studies of the middle atmosphere using balloons

During the Middle Atmosphere Program, 1982–1985, balloons will play a central role in gathering stratospheric, chemical, and dynamical data. This paper discusses some of the unique aspects of balloons as tools for probing the middle atmosphere, and suggests some directions for future projects and enhanced capabilities that would improve their utility in future investigations.     

Rocket measurements of mesospheric ionization irregularities

The Langmuir-probe technique for measurement of electron concentration in the mesosphere is capable of excellent altitude resolution, of order 1 m. Measurements from nine rocket flights frequently show small-scale ionization structures in the altitude region 60–90 km. These are believed to be identical with regions of strong coherent backscatter seem by VHF radars at Jicamarca, Peru and Urbana, Illinois. They are believed to represent intermittent turbulence attributable to nonlinear interaction of waves in the mesosphere. Parameters of the turbulent regions are estimated.     

对接综合试验台轨迹规划算法研究

为实现模拟空间两飞行器对接动力学过程的对接综合试验台的平稳对接，提出了一种基于加速度控制的轨迹规划算法。给出了不同初始条件下的规划方法，以及时转动自由度的特殊处理。物理试验结果表明，规划模型能精确控制平台从初始零位运动到主被动对接机构初次接触位置，且最后时刻平台姿态与对接试验的初始条件完全吻合。该算法可直接用于对接综合试验台的控制。     

加工复杂零件的高端技术

瑞士加工中心制造商威力铭-马科黛尔公司着重于质量和生产效率,主要活跃于航空/航天、精密机械、钟表和医疗行业,并以其为用户提供的高性能交钥匙解决方案而著称.     

对接综合试验台控制系统软件快速原型开发技术

对基于快速原型设计睁对接综合试验台控制系统软件开发进行了研究。介绍了根据系统方案进行的中央控制台软件设计和模型计算机软件开发等。给出了快速原型设计,以及包括接口设计、配置管理、文档管理等软件工程化管理等关键技术。     

Observations of solar-flare ionization in the mesosphere using coherent-scatter radar

Observations of solar-flare ionization in the mesosphere can be made using coherent-scatter radar systems. The scattered power profiles they measure in the 60–90 km altitude region is a function of the ion concentration gradient and the intensity of turbulent mixing at each atltitude. By comparing the power profiles before, during and after a solar flare, it is possible to estimate the ion production rate during the flare as a function of altitude and time. This analysis is used to compare the ion production rates with generally accepted ion-chemical models. Comparisons are made with ion production rates estimated from the solar X-ray flux for the same flare made by geostationary satellites.     

Heusler合金M2CoA(M=Mn,Ti;A=Al,Si)的第一性原理

采用基于密度泛函理论(DFT)的第一性原理计算方法,研究了M₂CoA型Heusler合金Mn₂CoAl、Mn₂CoSi、Ti₂CoAl和Ti₂CoSi的电子结构和磁学性质。发现Heusler合金Mn₂CoAl是亚铁磁性自旋无带隙半导体,Mn₂CoSi与Ti₂CoAl是亚铁磁性自旋半金属,而Ti₂CoSi是铁磁性自旋半金属。它们的总自旋磁矩均为整数,符合Slater-Pauling规则。然后,在分析电子能带结构和态密度的基础上,探讨了自旋无带隙半导体与半金属性的根源。最后,声子谱和弹性常数计算结果表明所有M₂CoA型Heusler合金在晶格动力学和力学上均是稳定的。