Dynamic Response of Truss Adaptive Structures

It is pointed out that the damping matrix deduced by active members in the finite element vibration equation of a truss adaptive structure generally can not be decoupled, which leads to the difficulty in the process of modal analysis by classical superposition method. This paper focuses on the computational method of the dynamic response for truss adaptive structures. Firstly, a new technique of state vector approach is applied to study the dynamic response of truss adaptive structures. It can make the coeffic lent matrix of first derivative of state vector a symmetric positive definite matrix, and particularly a diagonal matrix provided that mass matrix is derived by lumped method, so the coefficient matrix of the first derivative of state vector can be exactly decomposed by CHOLESKY method. In this case, the proposed technique not only improves the calculation accuracy, but also saves the computing time. Based on the procedure mentioned above, the mathematical formulation for the system response of truss adaptive structures is systematically derived in theory. Thirdly, by using FORTRAN language, a program system for computing dynamic response of truss adaptive structures is developed. Fourthly, a typical 18 bar space truss adaptive structure has been chosen as test numerical examples to show the feasibility and effectiveness of the proposed method. Finally, some good suggestions, such as how to choose complex mode shapes practically in determining the dynamic response are also given. The new approach can be extended to calculate the dynamic response of general adaptive structures.

双三角翼布局歼击教练飞机的概念优化设计(英文)

双三角翼气动布局比三角翼飞机具有更好的大攻角空气动力特性。引入了评估教练机训练效能的作战分析法 ,研究了双三角机翼布局飞机空气动力特性的工程计算途径以及飞机性能指标的确定方法。以训练效能作为目标函数并选取机翼平面形状的几何参数为设计变量 ,采用多变量数值寻优方法 ,在战术技术指标及相关几何约束条件下 ,对某高级教练机的双三角机翼气动布局方案进行了优化选择。算例表明最优方案不仅比原准方案具有更高的训练效能 ,还改善了结构的受力情况 ,与工程实践吻合。

Research on the transfers to Halo orbits from the view of invariant manifolds

This paper discusses the evolutions of invariant manifolds of Halo orbits by low-thrust and lunar gravity.The possibility of applying all these manifolds in designing low-thrust transfer,and the presence of single-impulse trajectories under lunar gravity are also explained.The relationship between invariant manifolds and the altitude of the perigee is investigated using a Poincaré map.Six types of single-impulse transfer trajectories are then attained from the geometry of the invariant manifolds.The evolutions of controlled manifolds are surveyed by the gradient law of Jacobi energy,and the following conclusions are drawn.First,the low thrust(acceleration or deceleration) near the libration point is very inefficient that the spacecraft free-flies along the invariant manifolds.The purpose is to increase its velocity and avoid stagnation near the libration point.Second,all controlled manifolds are captured because they lie inside the boundary of Earth's gravity trap in the configuration space.The evolutions of invariant manifolds under lunar gravity are indicated from the relationship between the lunar phasic angle and the altitude of the perigee.Third and last,most of the manifolds have preserved their topologies in the circular restricted three-body problem.However,the altitudes of the perigee of few manifolds are quite non-continuous,which can be used to generate single-impulse flyby trajectories.

The causal sequence investigation of the ring current ion-flux increasing and the magnetotail ion injection during a major storm

全面记录在 NUADU 仪器在主要磁性的暴风雨期间在 2005 年 5 月 15 日在 TC-2 上记录的戒指水流活动的 ENA 数据是可得到的(它合并了一系列 substorms ) 。在时间的分辨率在 5081 和 81158 keV 与相比的精力范围从 ENA 数据导出的 4-min 的离子流动在 situ ，粒子流动在 LANL-01 上由 LANL-SOPA 仪器测量了， LANL-02 ， LANL-97 ，并且 LANL-84 (环绕的一系列地球同步的卫星在~的赤道的飞机 6.6 R E )。另外，磁场在 GOES-10 和 GOES-12 上由 magetometers 同时测量了(它也是地球同步的卫星) 与粒子数据相比。在戒指水流的离子流动在在 substorms 而非在向地的指导 dipolarization 事件以后的生长阶段拉长的地磁气的地 tailward 期间被提高，这被表明。这观察，它质问戒指水流粒子被注射的存在概念从 magnetotail 追随者 dipolarization 事件向地，用很多磁性的暴风雨事件要求进一步的调查。

Influence of Participating Media on the Radiation Thermometry for Surface Temperature Measurement

为参与媒介盖住的表面的放射计温的一个温度测量模型被开发。模型基于参与放射高温计的媒介和原则的放射热转移，并且由分离纵标方法的不可分的明确的表达解决了在上光谱 waveband。Raytek MR1SB 一 / 二颜色高温计的显示的温度上的水薄雾的影响被讨论。Mie 理论被用来计算水薄雾的放射的性质。为了验证模型，，一个实验室温度测量实验被执行。放射计温的温度对敏感的结果表演光谱高温计的反应波长，和高温计的模仿的温度与试验性的大小同意合适的波长很好。模仿的温度是比为一个颜色高温计的表面的真实温度低的，并且它能比为有参与媒介的影响的二颜色的高温计的真实的更高或低。关键词参与媒介 - 放射计温 - 表面温度测量 - 分离纵标方法 CLC 数字 O551.

Porous cobalt oxide nanowires: Notable improved gas sensing performances

The porous Co3O4 nanowires have been successfully synthesized via modified template method. A possible growth mechanism governing the formation of such 1D nanowires is proposed. The as-prepared products have been characterized by X-ray Powder Diffraction (XRD), Extended X-ray Absorption Fine-structure (EXAFS), High-resolution Transmission Electron Microscopy (HRTEM) and N2 adsorption/desorption analysis. Our systematic studies have revealed that the porous Co3O4 nanowires show excellent gas sensing performances, which demonstrate the potential application of the 1D nanostructured Co3O4 in the detection of the ethanol gas as a sensor material. The improved performances are owing to its large specific surface area and porous morphology.

Coating metals on micropowders by magnetron sputtering

Magnetron sputtering was used to coat various metals on micropowder surfaces. By using this method, the fine particles are better dispersed and can therefore be coated more homogeneously. The micro-powders used include cenospheres from fly ash of coal-burning electric power plants （diameter 40-200 μm and particle density 0.7 ± 0.1 g/cm^3）, as well as carborundum particles of different sizes. Aluminum, silver, copper, cobalt and nickel were used as the coating metals. Tests showed that the coated metal film was compact adhering tightly on the base powders, and the coated powders possess adequate flow properties.