基于RTW与RTX的三轴转台仿真系统

应用Matlab/simulink的RTW工具箱将Matlab中设计的模型快速生成实时目标机可以运行的程序代码,并下载到实时目标机中运行.实时目标机采用Vxworks实时操作系统确保仿真模型的实时解算、控制与通讯.同时,三轴转台控制计算机利用RTX实时扩展子系统确保其Windows平台下的实时性,从而实现三轴转台仿真系统的半实物仿真试验.     

计算机病毒FUNLOVE的解析与清除

计算机病毒被定义为：“指编制或者在计算机程序中插入的破坏计算机功能或者破坏数据，影响计算机使用并且能够自我复制的一组计算机指令或者程序代码。”计算机病毒如恐怖分子，总是利用计算机系统和管理的漏洞贸然潜入，潜伏一段时期后在某个时刻突然发难，这些恶性病毒将造成不可逆转的损失。     

软件文档的数据库设计

本文讨论了在计算机辅助软件工程（ＣＡＳＥ）环境中，数据库管理系统（ＤＢＭＳ）的数据结构特征框架。较为详细的探讨了数据结构三个主要的数据库模式设计。讨论了软件工程（ＳＥ）文档以及ＳＥ中的数据种类：正文的、表格的、图形的以及无结构数据类。分析了程序代码数据结构以及ＣＡＳＥ在程序代码上的操作     

ASP．NET中TreeView控件与数据库结合创建动态目录树

介绍了在ASP.NET中使用TreeView控件和数据库技术创建网页程序中的动态目录树,避免了数据源经常性改变时频繁修改程序代码;并着重阐述其具体实现方法和步骤。     

飞机电气设计系统网络化的研究

通过可视化编程工具VB和关系型数据管理系统SQLServer实现了飞机电气信息集成系统的设计系统网络化 ,提高了工作效率 ,本文针对在设计系统网络化中出现的一些问题 ,提出了解决的办法 ,并对部分程序细节给出了程序代码。     

应用神经网络的手写体数字识别算法研究

结合程序代码论述了1个手写体数字识别程序的原理。该识别程序应用了神经网络来实现其功能,采用BP网络。主要论及了关于BP网络的3个问题:反向传播算法;提高BP网络收敛速度的算法;以及文中提出的对网络进行修剪以期能改善其推广能力的1种算法。     

二维图象编程系统GRNC2D

目前,CAD 和 CAM 技术在各自的领域都有日新月异的进展,但是往往嫌两者之间的联系不够密切,因此填充两者之间的沟壑或架筑两者之间的桥梁是十分育意义的。目前都在发展计算机辅助数控编程系统,可以借助于某种适用的编程语言,诸如 APT 之类,免去了人和数控机床程序代码之间的纠缠。尽管如此,仍然     

TMS320C6678多核DSP的加载配置和实现方法

程序代码正确的固化加载运行是多核DSP应用的前提和基础.简要介绍了DSP的加载器和加载过程,阐述了多核处理器件的加载配置管理方法.以TI公司的多核DSP TMS320C6678为例,介绍了多核DSP的加载模式和流程,详细阐述了EMIF16的Nor FLASH加载实现方法,可以实现多核DSP软件的正确、可靠加载运行.     

一种增强虚拟仪器软件数据共享性的方法

在介绍虚拟仪器及其开发环境LabVIEW的特点的基础上，分析了LabVIEW与外部程序代码接口的途径，并着重实现了将LabVIEW与外部代码进行连接的高级技术之一——动态链接库机制。实践表明，此机制高效、易行，是增强LabVIEW与其它Windows应用程序之间数据共享能力的一条很好的途径。     

修正的条件/判定覆盖相关的问题

通过讨论进行修正的条件/判定覆盖(MC/DC)分析时可能会遇到的问题,明确所有布尔表达式、按位运算等程序代码结构均需要满足MC/DC,并证明如果将一个判定分解为多个等价的判定,对各个部分满足MC/DC的测试集,对整个判定并不一定满足MC/DC。同时指出汇编语言程序同样需要考虑MC/-DC问题,提出MC/DC分析发现问题的方式,以及对问题的处理建议。     

内套筒对预紧力齿连接接头预紧力的影响

为了研究内套筒材料性能与几何尺寸等参数对预紧力影响规律，本文首先通过实验对不同内套筒材料与壁厚对预紧力的影响规律进行研究。然后通过有限元软件ANSYS建立了接头预紧力施加的数值模型，模拟结果与实验实测值吻合较好，并通过有限元对实验现象进行了分析。结果表明：相同挤压量下，接头壁厚越高，所产生预紧力越高；对于塑性材料的内套筒接头，当外部挤压量超过一定值时，塑性材料完全进入塑性，变形增加，但应力值不再显著增长，预紧力趋于稳定；而对于弹性材料的内套筒接头，弹性材料应力一直随着应变线性增长，因此预紧力随着挤压量增加不断增加。     

航空电子系统综合技术的发展与模块化趋势

在系统阐述了航空电子综合技术及系统结构发展的基础上,全面论述了综合化及模块化的含义,指出了综合化系统及模块化在大系统结构中的层次关系。最后,提出了我国发展综合化系统应采取的策略。     

The Formation Of The First Stars In The Universe

In this review, I survey our current understanding of how the very first stars in the universe formed, with a focus on three main areas of interest: the formation of the first protogalaxies and the cooling of gas within them, the nature and extent of fragmentation within the cool gas, and the physics – in particular the interplay between protostellar accretion and protostellar feedback – that serves to determine the final stellar mass. In each of these areas, I have attempted to show how our thinking has developed over recent years, aided in large part by the increasing ease with which we can now perform detailed numerical simulations of primordial star formation. I have also tried to indicate the areas where our understanding remains incomplete, and to identify some of the most important unsolved problems.     

The rings of Saturn

This paper reviews observations of the rings of Saturn at visual, infrared, and radio wave-lengths. Critical assessments are made of attempts to derive the physical characteristics of the rings from these measurements. A discussion is also given of the origin and evolution of the rings.     

录音机外语学习附加器的设计

本文介绍了录音机外语学习附加器的设计思想、工作原理以及独特的语音存储和各种重放功能。     

The aerodynamics of propellers

The theory and the design of propellers of minimum induced loss is treated. The pioneer analysis of this problem was presented more than half a century ago by Theodorsen, but obscurities in his treatment and inaccuracies and limited coverage in his tables of the Goldstein circulation function for helicoidal vortex sheets have not been remedied until the present work which clarifies and extends his work. The inverse problem, the prediction of the performance of a given propeller of arbitrary form, is also treated. The theory of propellers of minimum energy loss is dependent on considerations of a regular helicoidal trailing vortex sheet; consequently, a more detailed discussion of the dynamics of vortex sheets and the consequences of their instability and roll up is presented than is usually found in treatments of propeller aerodynamics. Complete and accurate tables of the circulation function are presented. Interference effects between a fuselage or a nacelle and the propeller are considered. The regimes of propeller, vortex ring, and windmill operation are characterized.     

The atmosphere of Jupiter

Current information on the neutral atmosphere of Jupiter is reviewed, with approximately equal emphasis on composition and thermal structure on the one hand, and markings and dynamics on the other. Studies based on Pioneer 10 and 11 data are used to refine the atmospheric model. Data on the interior are reviewed for the information they provide on the deep atmosphere. The markings and dynamics are discussed with emphasis on qualitative relationships and analogies with phenomena in the Earth's atmosphere.Contribution No. 2652 of the Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, Calif. 91125, U.S.A.     

The atmosphere of Venus

The investigations of Venus take a special position in planetary researches. It was just the atmosphere of Venus where first measurements in situ were carried out by means of the equipment delivered by a space probe (Venera 4, 1967). Venus appeared to be the first neighbor planet whose surface had been seen by us in the direct nearness made possible by means of the phototelevision device (Venera 9 and Venera 10, 1975). The reasons for the high interest in this planet are very simple. This planet is like the Earth by its mass, size and amount of energy obtained from the Sun and at the same time it differs sharply by the character of its atmosphere and climate. We hope that the investigations of Venus will lead us to define more precisely the idea of complex physical and physical-chemical processes which rule the evolution of planetary atmospheres. We hope to learn to forecast this evolution and maybe, in the far future, to control it. The last expeditions to Venus carried out in 1978 — American (Pioneer-Venus) and Soviet (Venera 11 and 12) — brought much news and it is interesting to sum up the results just now. The contents of this review are:

1. The planet Venus — basic astronomical data.
2. Chemical composition.
3. Temperature, pressure, density (from 0 to 100 km).
4. Clouds.
5. Thermal regime and greenhouse effect.
6. Dynamics.
7. Chemical processes.
8. Upper atmosphere.
9. Origin and evolution.
10. Problems for future studies

Here we have attempted to review the data published up to 1979 and partly in 1980. The list of references is not exhaustive. Publications of special issues of magazines and collected articles concerning separate space expeditions became traditional last time. The results obtained on the Soviet space probes Venera 9, 10 (the first publications) are collected in the special issues of Kosmicheskie issledovanija (14, Nos. 5, 6, 1975), analogous material about Venera 11, 12 is given at Pis'ma Astron. Zh. (5, Nos. 1 and 5, 1978), and in Kosmicheskie issledovanija (16, No. 5, 1979). The results of Pioneer-Venus mission are represented in two Science issues (203, No. 4382; 205, No. 4401) and special issue of J. Geophys. Res. (1980). We shall mention some articles to the same topic among previous surveys: (Moroz, 1971; Sagan, 1971; Marov, 1972; Hunten et al., 1977; Hoffman et al., 1977) and also the books by Kuzmin and Marov (1974) and Kondrat'ev (1977). Some useful information in the part of ground-based observations may be found in the older sources (for example, Sharonov, 1965; Moroz, 1967). For briefness we shall use as a rule the abbreviations of space missions names: V4 instead of Venera 4, M10 instead of Mariner 10 and so on. The first artificial satellites of Venus in the world (orbiters Venera 9 and 10) we shall mark as V9-O, V10-O unlike the descent probes V9, V10. Fly-by modules of Venera 11 and Venera 12 we shall mark as V11-F and V12-F. Pioneers descent probes — Large (Sounder), Day, Night and North — will be marked as P-L, P-D, P-Ni, P-No, orbiter as P-O, and bus as P-B.     

The problem of tektites

Tektites are bodies of natural glass of limited size and of typical shape and sculpturing. They occur in relatively large numbers in limited strewn-fields, each formed by a single event in the geological past. Three (perhaps four) tektite fields are known, all of different age. Perhaps only the youngest-the indoaustralian strewn-field, reaching from Thailand to Tasmania — in its original extension, the others having suffered from erosion.Many tektites from Indonesia and all from Australia show two periods of melting, which must be regarded as proof of extraterrestrial origin. These secondary forms with rims or flanges, developed by ablation in the earth's atmosphere, probably depend upon a low entry angle and are therefore only represented from certain regions.Tektites consist for about 70–80% of silica, show fluidal texture, no traces of crystallization and a remarkably low water content. From a chemical point of view they resemble certain terrestrial rocks more than true meteorites. Probably they represent molten parts from the moon's surface, which were thrown into space after the impact of large meteorites.