高超声速尖双锥流动高精度数值模拟

以25°/55°尖双锥外形的高超声速低焓层流流动模拟为例,对高阶加权紧致非线性格式模拟激波/边界层干扰流动的能力进行验证和确认。空间离散采用二阶MUSCL和三阶、五阶加权紧致非线性格式,时间离散采用二阶精度双时间步方法,通量函数采用混合Roe-Rusanov,AUSMPW+,Van Leer等,对比了不同精度空间离散格式对时间、网格收敛特性和通量函数耗散特性的影响。数值模拟结果表明采用高精度空间离散格式能在较疏的网格上获得收敛解,并能消除结果对通量函数的敏感性,但收敛需要推进更久的计算时间。数值模拟结果与实验测量结果吻合良好,满足工程精度要求。     

独特的微机正弦扫频振动控制技术

以通用微机为主控单元进行正弦扫频振动控制的独特之处在于驱动信号的生成、修正,响应信号的采样、分析以及系统传递函数计算等控制功能均主要由微机软件完成。本文主要介绍上述控制功能的软件设计原理,并给出相应的实验结果。     

TERRORISM AND TOURISM: THE CASE OF TURKEY

Using a time series method called ‘transfer function’, this paper examines the effect of terrorism on tourism in Turkey. The results indicate that there exists a negative but small impact of terrorism, which is observed within approximately one year. However, terrorist attacks in Turkey have accounted for a reduction of six million foreign tourists over the last nine years. Moreover, the economic cost of terrorism in the tourism industry was more than $700 million in 2006. However, terrorist attacks in continental Europe and America, and an active war involving a neighboring country, had no effects on tourism in Turkey.     

Remaking the military industrial relationship: A French‐American comparison

Defense industrial complexes in leading Cold War nations have downsized and reallocated resources to other productive activities in the 1990s. In this paper, we analyze the experience of two key countries ‐ the US and France. Comparing the two countries, we find similar outcomes in budgetary retrenchment and large firm restructuring but marked differences in the pace of downsizing and diversification among small and medium‐sized firms. We hypothesize that three sets of contextual differences may explain these differences: 1) institutional differences in the way that the State bureaucracies ‐ the Pentagon and the French Délégation générale pour l'armement (DGA) ‐ oversee defense industrial matters, 2) differences in military industry ownership and firm size patterns, and 3) differences in the regional distribution of defense industrial capacity and associated regional policies. In closing, we note that the two countries’ defense industrial complexes are becoming more alike and speculate on the significance of invidious competition and interactions between them. We address briefly the future of French/American arms industrial competition and cooperation, given the trend towards transnational security arrangements and defense industry globalization     

差分GPS导航系统的设计

本文详细地介绍了差分GPS导航系统的设计方法。试验结果证明了该方法是正确可行的。     

基于ADAMS／Car与MATLAB的液压主动悬架平顺性仿真研究

利用ADAMS/Car建立了传统被动弹簧与液压缸串联的主动悬架模型,与其它子系统装配组成整车仿真模型,并在MATLAB/SIMULINK的环境下建立主动悬架的PID控制系统,实现了与整车机械模型的联合仿真。仿真结果表明,采用液压主动悬架系统后,车辆在通过路面凸起处时车体质心垂向加速度得到了有效抑制,从而提高了车辆的行驶平顺性和乘坐舒适性。     

RTDX与Matlab实现基于DSP的FIR滤波器设计

介绍了一种RTDX与Matlab结合设计基于DSP的FIR数字滤波器的方法.在VB中调用Matlab进行指定特性FIR数字滤波器设计,获得各阶权系数,然后调用RTDX,实时地向目标硬件传递该系数,从而实现了基于DSP的FIR数字滤波器精确设计,提高了DSP算法软件的设计效率.并对TI的RTDX技术及使用方法作了相关介绍.     

军用多波段数字接收机研究

本文结合软件无线电设计思想 ,研究了一种HF/VHF数字接收机 ;并从系统的角度 ,分析了各关键部件的设计 ,特别是SSB(单边带 )波形和FM (调频 )波形的数字化解调。最后给出了系统实现的硬件平台。     

Shock-induced reaction behaviors of functionally graded reactive material

In this paper, the ballistic impact experiments, including impact test chamber and impact double-spaced plates, were conducted to study the reaction behaviors of a novel functionally graded reactive material (FGRM), which was composed of polytetrafluoroethylene/aluminum (PTFE/Al) and PTFE/Al/bismuth trioxide (Bi₂O₃). The experiments showed that the impact direction of the FGRM had a significant effect on the reaction. With the same impact velocity, when the first impact material was PTFE/Al/Bi₂O₃, compared with first impact material PTFE/Al, the FGRM induced higher overpressure in the test chamber and larger damaged area of double-spaced plates. The theoretical model, which considered the shock wave generation and propagation, the effect of the shock wave on reaction efficiency, and penetration behaviors, was developed to analyze the reaction behaviors of the FGRM. The model predicted first impact material of the FGRM with a higher shock impedance was conducive to the reaction of reactive materials. The conclusion of this study provides significant information about the design and application of reactive materials.     

机载电子设备I/O装置测试系统设计

为了在复杂环境下对某飞机的机载电子设备进行功能测试和故障定位,提出了一种基于PXI总线技术的测试系统,可以在各种环境下实现整机联合测试,也可实现该机载电子设备场外可更换组件的单件测试,实现的I/O单件测试.新的测试系统对原有检测平台进行了合理的借鉴,使得检测程序化、系统化、智能化.