PDM技术及其在直升机研制中的作用

本文首先分析了当前直升机在运用CAD/CAE/CAM技术进行研制中存在的一些问题,接着提供了解决的方法,介绍了PDM的概念、构成、主要功能。最后简述了PDM技术在直升机研制中的作用,以及企业在实施PDM当中应注意的一些问题。     

一种卫星间跟瞄方向的控制策略与实现

进行自由空间的光通信或空间对抗，需要在卫星间实现精确的跟踪与瞄准。因为地面测控站的设置非常有限，指令与数据注入的范围受到很多限制，所以要求这种跟瞄在很多时候是无主控制状态下完成的。提出了一种利用在地面测控站的范围内向星上数管中心注入目标卫星、本体卫星的轨道参数，其它时间依靠自主导航飞行和GPS修正的方法，结合本体星的姿态测量、振动测量实现卫星瞄准指向的方位角与俯仰角的精确控制的方法，提高了在地面站无法注入指令与数据时卫星的捕获概率。通过仿真，将计算结果与卫星仿真工具软件STK的数据进行比较，结果一致。最后在嵌入式DSP平台上实现了这一策略。     

中小外贸企业经营机制创新分析

经营机制创新是中小型外贸企业摆脱困境的必由之路。针对目前面临的主要问题，从外部环境及企业自身经营机制缺陷方面对中小型外贸企业生存环境进行分析，并从实现经营机制创新角度探讨改善现状的方法，力图找出中小型外贸企业经营机制创新的突破点。     

Ту-154М变稳飞机空中飞行模拟试验评述

依据Ту－１５４М变稳飞机的特点，主要进行了不同操纵器、不同控制律和不同显示画面的飞行试验研究。特别是通过中央杆和侧杆、电传系统不同控制律飞行品质特性之间、两种先进控制方案及不同显示方式的比较，不仅掌握了这方面的试飞技术和评定技术，还亲身体验到变稳飞机在发展仿真技术，新机预研及提高试飞员试飞技术和评定技术等方面的巨大作用。     

Calculation of the transonic dip of airfoils using viscous-inviscid aerodynamic interaction method

A numerical procedure for the calculation of the transonic dip of airfoils in the time domain is presented. A viscous-inviscid aerodynamic interaction method is taken to calculate the unsteady aerodynamic loads. In the present case the integral boundary layer equations are coupled with the Transonic Small Disturbance (TSD) Potential Equation. The coupling between structural motion and aerodynamic loads is carried out using State Space equation. It is solved by State Transition Matrix technique. Results are presented for NACA 64A010 and NLR 7301 airfoils with structural data from Isogai and DLR, respectively. Comparisons show good agreement with other numerical results. Certain deviations of experimental data taken from literature need more insight in the detailed test conditions.     

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with primary goat embryonic fibroblast showed no difference from traditional feederlayer-based culture method used in mouse and human. The putative primary EG colonies were multilayer clumps ofcompact cel     

改进的次时间最优控制

本文在[1][2]基础上进一步探讨了次时间最优控制的改进问题,深入地阐明了次时间最优控制的某些特性后,提出了一个新的改进的设计方法。按照这种方法设计控制系统,不但实用而且可以大幅度提高次时间最优控制的最优性。并用实例比较了各种方法,证明了本文提出的方法的优越性。本文提出的方法应用于工程设计,对于提高系统的最优性是非常有效的。     

一万氧压机轴振动控制分析与实践

本文介绍了一种非常规的高速轴振动抑制方法，主要是用振源分析技术，通过确诊设备故障原因来分析影响轴振动的主要因素，调节机器的系统刚度，再通过理论计算修订安装参数，制定设备故障处理对策，在涟源钢铁集团有限公司一万氧压机组上的实践取得了相当满意的效果，很有推广价值。     

What Determines the Composition of SEPs in Gradual Events?

Gradual solar energetic particle (SEP) events are evidently accelerated by coronal/interplanetary shocks driven by coronal mass ejections. This talk addresses the different factors which determine the composition of the accelerated ions. The first factor is the set of available seed populations including the solar wind core and suprathermal tail, remnant impulsive events from preceding solar flares, and remnant gradual events. The second factor is the fractionation of the seed ions by the injection process, that is, what fraction of the ions are extracted by the shock to participate in diffusive shock acceleration. Injection is a controversial topic since it depends on the detailed electromagnetic structure of the shock transition and the transport of ions in these structured fields, both of which are not well understood or determined theoretically. The third factor is fractionation during the acceleration process, due to the dependence of ion transport in the turbulent electromagnetic fields adjacent to the shock on the mass/charge ratio. Of crucial importance in the last two factors is the magnetic obliquity of the shock. The form of the proton-excited hydromagnetic wave spectrum is also important. Finally, more subtle effects on ion composition arise from the superposition of ion contributions over the time history of the shock along the observer’s magnetic flux tube, and the sequence of flux tubes sampled by the observer.