基于IPSec的VPN技术原理与实现

描述了VPN技术的基本原理以及IPSec规范，通过基本原理详细介绍了对数据包进行加密和认证原理。逐一介绍了IPSec主要协议，通过IPSec协议的论证说明了安全通信的原理，论证了VPN系统设计，在此基础上介绍了VPN技术的实现方法和几种典型应用方案。最后，作者对VPN技术的推广与应用提出了自己的看法。     

英汉口译中笔记的特点及其方法

口译笔记在接续翻译过程中起着重要的作用，它不同于速记或听写，有其自身的特点和规律。本文着重论述了接续翻译笔记的特点和记录过程中的技巧。     

空中客车公司的数字化维修技术

数字化维修是航空维修的大势所趋，空中客车公司是这一领域的先拓者。空中客车公司发展的数字化维修技术，主要可以分为3部分：第1部分是机载自检、显示、打印和空地传输维修信息数据的设备；第2部分是对机载维修信息进行分析和电子排故的软件；第3部分是将各种与维修相关的数据进行数字化管理的电子数据处理工具。采用这些技术，可大大缩短飞机的排故和维修时间。     

电离层CT变换重建方法中的小波外推技术

电离层ＣＴ技术由于数据采集系统结构的局限性，致使所得数据不完全，伪投影中采样不均匀，频域谱值不完全若用直接Ｆｏｕｒｉｅｒ方法重建，必须对伪投影采样施以均匀化和有二维频域内进行估值。本文参照已有的Ｆｏｕｒｉｅｒ外推技术，提出小波外推技术。理论分析和重建结果都说明小波外推技术具有较多优越性。     

MHD numerical simulations of proto-stellar jets

We will summarize in this paper the effects that the presence of the magnetic field can cause to proto-stellar jet dynamics, structure and emission line properties, and the differences between two- and three-dimensional numerical simulations will be emphasized. This revised version was published online in August 2006 with corrections to the Cover Date.     

高温TiAl合金热成形技术研究进展

γ-TiAl合金具有优异的高温性能,是航空发动机650~900℃服役温度区间的重要候选材料。在回顾TiAl合金发展过程与应用现状的基础上,主要介绍了TiAl合金铸锭熔炼、铸造、包套等温锻造、包套热挤压等热加工技术的研究进展,提出了TiAl合金低成本近净成形技术面临的机遇和挑战。     

Coupling Magneto-Electro-Elastic node-based smoothed radial point interpolation method for free vibration and transient analysis of Functionally Graded Magneto-Electro-Elastic structures

A Coupling Magneto-Electro-Elastic (MEE) Node-based Smoothed Radial Point Interpolation Method (CM-NS-RPIM) was proposed to solve the free vibration and transient responses of Functionally Graded Magneto-Electro-Elastic (FGMEE) structures. By introducing the modified Newmark method, the displacement, electrical potential and magnetic potential of the structures under transient mechanical loading were obtained. Based on G space theory and the weakened weak (W²) formulation, the equations of the multi-physics coupling problems were derived. Using triangular background elements, the free vibration and transient responses of three numerical examples were studied. Results proved that CM-NS-RPIM performed better than the standard FEM by reducing the overly-stiff of structures. Moreover, CM-NS-RPIM could reduce the number of nodes while guaranteeing the accuracy. Besides, triangular elements could be generated automatically even for complex geometries. Therefore, the effectiveness and validity of CM-NS-RPIM were demonstrated, which were valuable for the design of intelligence devices, such as energy harvesters and sensors.     

端壁抽吸控制下攻角对压气机叶栅叶尖泄漏流动的影响

为减少叶尖泄漏损失并改善由泄漏涡造成的叶尖流道堵塞,对端壁流向开槽抽吸方案对扩压叶栅叶尖泄漏流动的控制效果进行了数值模拟研究,重点分析了来流攻角对流动控制效果的影响。结果表明:端壁抽吸方案通过直接影响叶尖泄漏流的发展,减弱泄漏涡强度,减小了泄漏损失;抽吸对负攻角和小攻角下叶栅流场的影响范围仅局限于叶尖区域。但在大的正攻角下,抽吸使得低叶展区域的附面层分离提前,且叶背分离涡脱落位置升高至约70%叶高处,端壁抽吸对叶栅的整体影响由泄漏损失降低和分离损失增大综合决定。抽吸量为07%时,抽吸后叶栅总体总压损失系数分别在-8°、0°和+4°攻角下降低约90%、108%和68%,而在+8°攻角下增大约57%。     

Reliability and Sensitivity Analysis of Transonic Flutter Using Improved Line Sampling Technique

The improved line sampling (LS) technique, an effective numerical simulation method, is employed to analyze the probabilistic characteristics and reliability sensitivity of flutter with random structural parameter in transonic flow. The improved LS technique is a novel methodology for reliability and sensitivity analysis of high dimensionality and low probability problem with implicit limit state function, and it does not require any approximating surrogate of the implicit limit state equation. The improved LS is used to estimate the flutter reliability and the sensitivity of a two-dimensional wing, in which some structural properties, such as frequency, parameters of gravity center and mass ratio, are considered as random variables. Computational fluid dynamics (CFD) based unsteady aerodynamic reduced order model (ROM) method is used to construct the aerodynamic state equations. Coupling structural state equations with aerodynamic state equations, the safety margin of flutter is founded by using the critical velocity of flutter. The results show that the improved LS technique can effectively decrease the computational cost in the random uncertainty analysis of flutter. The reliability sensitivity, defined by the partial derivative of the failure probability with respect to the distribution parameter of random variable, can help to identify the important parameters and guide the structural optimization design.     

基于靶标实现光电经纬仪伺服系统的室内检测

为解决靶场光电经纬仪伺服系统的检测,在原有检测设备的基础上,对动态精度靶标的计算机系统增加引导数据输出功能,并以异步串行通讯的方式发送给光电经纬仪伺服系统,通过接收引导跟踪完成伺服控制系统的室内检测。该方法可用于靶场光电经纬仪伺服控制系统跟踪性能和跟踪精度的检测,具有较高的实用价值。