ERJ145飞机电源系统的设计分析

ERJ-145支线飞机广泛应用在国际航空领域，其电源系统设计安全可靠。对该飞机电源系统的构成及功能进行了深入分析，介绍了飞机主电源、二次电源、应急电源、地面电源等组成及飞机电源系统构型，并详细阐述了电源控制系统的逻辑。     

三相交流陀螺马达电源的研究

本文讨论了三相交流陀螺马达电源的工作原理，根据主要技术指标的要求，设计陀螺马达电源，给出了该电源各个组成部分的线路设计，解决了研制出现的电源振荡问题。论述了该电源的设计特点，并给出了使用结论。     

便携式计算机电源的系统适应性研究

从便携式计算机的电源能否接在飞机电源系统这个实际问题出发．研究了便携式电子设备的电源及其充电器的适应性问题。首先根据整流理论进行了适应性论证，然后进行了计算机电源在400Hz频率系统的空载和加载试验，理论分析及试验数据结果表明，这种装置对400Hz电源系统是适应的，输出参数符合原设计要求．没有发热、振动等不良现象，可以使用。因此在新设计的飞机上，供旅客使用的电源，不必专门提供工频电源系统接口。     

微机数控智能化线切割加工脉冲电源的设计研究

本文在分析了现有线切割加工脉冲电源的局限性和研制新型线切割加工脉冲电源的必要性后，介绍了作者研制成功的单片机控制和微机控制的数字化线切割加工脉冲电源。这种电源摆脱了传统的用阻容元件来决定脉宽、脉间的方法，实现了电源脉冲参数的数字化。该电源具有调节精度高、调节范围广、能够实现用计算机在线设置和调节粗、中、精加工参数的特点。电源性能稳定可靠，操作使用十分方便。文章最后给出了该电源的工艺效果。     

三相方波电源

本文叙述了三相方波电源的原理，介绍了由Ｄ触发器组成分配器，到用集成酚器构成方波电源，并提出一个实用三相方波电源。     

柴油发电机组控制箱的应用

一、概述 在现代机场中，为大型飞机提供地面电源的电源车被广泛使用，采用柴油发电机组控制箱对电源车的柴油发电机组实现自动化控制，大大提高了电源车供电的可靠性，保证输出电压、电流的稳定性。     

模糊层次分析法在机场备用电源选择中的应用

传统观念认为只有柴油发电机组才适合作机场备用电源，其实国际民航组织并没有对备用电源采用何种设备做出具体限制，备用电源的选择面很广。结合当前新兴的微型燃气轮机发电技术和燃料电池发电技术，采用模糊层次分析法(Fuzzy AHP)，对这三种电源进行综合性能评价，把难以量化的因素数字化，做出了具体的方案排序向量，为设计人员在实际工程中选用备用电源提供了参考。     

航空惯导系统电源及其小型化

本文介绍了航空惯导系统电源的组成及工作原理，详细地介绍了设计ＡＣ／ＤＣ变换器的几种可供选择的方案，论述了惯导计算机电源、平台电源的特殊要求，以及实现这些要求的部分原理电路，指出惯导电源发展的趋势是高频化、小型化、模块化、生产专业化。     

大型民用飞机电源系统的现状与发展

飞机电源系统经历了由低压直流、恒速恒频交流、变速恒频交流、变速变频交流和高压直流的发展过程，本文在分析了各种电源系统的特点以及飞机电源系统发展方向的基础上，分析了新型民用和军用飞机的特点。最后结合我国飞机电源系统的发展现状和研究水平，提出了一些看法。     

对歼七系列飞机预防空中断电工作的探讨

为了保证歼七系列飞机电源系统正常，可靠地工作，确保飞机使用安全。本文根据该系统飞机电源系统的结构特点，分析探讨了影响电源系统正常工作的主要因素，提出了在生产装配和使用维护中预防空中断电的主要做法。     

英语中的两类汉语借词分析

英语作为国际性的语言从各国语言中吸收了大量借词。英语中存在汉语借词有多种原因,汉语借词对英语语言做出了贡献,丰富了英语词汇与表达方式,同时也传递了中国文化信息。     

Satellite communication system integrated into terrestrial ISDN

This paper presents an advanced satellite communication system named DYANET II. This system uses satellite channels as subscriber lines for ISDN customers as well as trunk circuits for overflow traffic. The system can offer the same ISDN services to satellite customers as those available to terrestrial subscribers in terms of numbering, signaling, and charging systems as well as user-network interfaces. It can also set up satellite channels on a demand assignment basis to achieve efficient satellite channel utilization, and to connect customers by single-hop satellite connections. A compact, lightweight Earth station has been developed for remote customers and temporary demands such as exhibitions.     

语篇连贯解读与构建中的推理过程

语篇连贯既是一种语言现象,又可以被看作是一种心理行为。看一个语篇是否连贯是离不开依据语篇的呈现方式进行的逻辑推理以及世界知识的记忆和调取等心理活动。连贯在很大程度上是来自于理解者在对语篇加工时所产生的推导过程。以回指推理以及主题推理为例,通过对语篇推理过程的论述具体说明了阅读者是怎样通过推理过程在自己的认知中做出语篇是否连贯的判断的,从而促进阅读者更好地理解语篇的连贯。     

一种基于DEA方法的反潜巡逻机综合效能评估研究

介绍了武器系统效能分析的相关方法和DEA方法的基本原理,将DEA方法引入固定翼反潜巡逻机效能评价中,针对四种型号的固定翼反潜巡逻机进行了分析评估。还讨论了有效性的含义、效能因素的选择以及评价结果的意义。     

A direct test of the Lorentz length contraction

One of the most basic tenets of special relativity is the concept of length contraction as seen by an observer in motion. Yet this aspect of relativity has never been tested directly, due to the negligible size of the effect when applied to most situations. However, as the Earth orbits the Sun, any two stars located out of the plane of the ecliptic will appear to change their angle of separation as viewed during three-month intervals. This is due to the fact that at one instant the motion of the Earth lies in the same direction as a line joining the two stars, while three months later the Earth's motion is perpendicular to that line. At a velocity of 30 km/sec, the expected length contraction would be approximately 18 micro-arcseconds (μas) per degree of separation. The Space Interferometry Mission (SIM) promises a resolution of ±1 μas in a field of view of one degree. Special relativity claims that this level of precision has no meaning, or only limited operational meaning, as it is smaller than the anticipated seasonal Lorentz contraction effects. Either, as the author believes, this level of precision is attainable, and special relativity is completely invalid, or the promised sensitivity level cannot be achieved without compensating for length contraction as well as aberration in published star charts     

微小型转台控制器的SOPC实现

微小型转台控制器通常利用嵌入式系统,尽可能减小控制系统的体积。SOPC技术的不断发展,实现了在FPGA芯片嵌入内核处理器,将其作为控制器具有很大优势。使用Altera公司的FPGA作为控制器开发平台,完成了控制器硬件开发,并且利用Nios II作为嵌入式内核,开发了基于Avalon总线的IP核。开发的控制器应用到微小型转台控制中,提高了控制器的集成度。     

尾支撑喷流试验技术研究

本文以喷流模拟、柱体环形喷管喷流对模型底压影响、以及尾支撑和侧支撑对模型底压影响为基础,从定性、定量得出,用尾支撑作喷流试验,支撑干扰小,可做到既经济又可靠,数据准度较高。     

论微电子机械系统MEMS

简介了微电子机械系统MEMS的基本概念、构成及显著特点 ,并对微电子机械系统的典型器件如传感器 ,执行器等作了介绍与分析 ,提出了微系统之间要研究的问题 ;探讨了微电子机械系统的发展应用前景     

Changes to vascular biometric system security & performance

When considering biometrics for a Personal Identification System, different modalities can be considered. The final selection will depend on specific application requirements. From the several modalities existing nowadays, vascular systems have appeared on the scene lately. Vein-based identification is claimed to be as reliable as fingerprint or iris identification, but with the usability of hand geometry or even the face. As with any other biometric modalities, vascular solutions have to be deeply analyzed for all relevant factors that could affect their performance or the security level achieved. This will show the analysis of the performance and security achieved by a commercial vascular biometric system, when being applied in several real-world scenarios. These scenarios will cover typical office environments to the more extreme environments, such as extreme light and temperatures, as those suffered in a banking ATM, or with high humidity such as in a gym. The results will show the strengths of this modality, as well as those points where further improvements are needed.