一种新型的数字编码轨道电路

基于现有UM71无绝缘轨道电路的传输通道,讨论了各种传输方案,提出了一种采用模拟调频方式的32位数字编码轨道电路,选用TMS320C32作为CPU,设计了发送和接收子系统,最后给出了室内仿真试验及其结果.     

Constructing Space for Science at the Royal Institution of Great Britain

Those who have worked in the Royal Institution of Great Britain have, since its foundation in 1799, made significant contributions to scientific knowledge, to its practical application, and to its communication to a wide variety of audiences. Such work cannot be carried out in an architectural vacuum, and in this paper we examine how the buildings of the Royal Institution, 20 and 21 Albemarle Street in central London, have shaped the work undertaken within its walls and how, on a number of occasions, the buildings have been reconfigured to take account of the evolving needs of scientific research and communication. This paper is based on the Conservation Plan of the Royal Institution that we wrote during 2003. The Conservation Plan did not examine the land owned by the Royal Institution to the north (i.e., 22 and 23 Albemarle Street; for this area see Richard Garnier, “Grafton Street, Mayfair,” Georgian Group Journal 13 (2003), 210–272), but it did discuss 18 and 19 Albemarle Street. In this paper we concentrate on the core Royal Institution buildings at 20 and 21 Albemarle Street. Other studies of the relationship of architecture,space, and science include Crosbie Smith and Jon Agar, ed., Making Space for Science: Territorial Themes in the Shaping of Knowledge (Basingstoke: Macmillan, 1997); Peter Galison and Emily Thompson, ed., The Architecture of Science (Cambridge, Mass.: MIT Press, 1999); and Sophie Forgan,“The architecture of science and the idea of a university,” Studies in History and Philosophy of Science 20 (1989), 405–434. Frank A.J.L. James is Professor of the History of Science at the Royal Institution; he has written widely on the history of nineteenth-century science in its social and cultural contexts and is editor of the Correspondence of Michael Faraday. He is President of the British Society for the History of Science. Anthony Peers is an Associate of Rodney Melville and Partners where he works in the field of building conservation as an architectural historian. He is a Council member of the Ancient Monument Society.     

The Problem of Capacity Addition in Multi-user Elastic Demand Communication Networks

In this paper we consider some properties on prices under flow control in a network that is to be shared by noncooperative users. Each user is faced with an optimization problem which is formulated as the minimization of its own criterion subject to constraint on the flows of the other users. The operating points of the network are the Nash equilibria of the underlying routing game. Our objective is to study the behavior of prices of all users when the network designer needs to allocate capacities to network links. For parallel links topologies, we show that degradation of the performances such as prices will not take place, as well as the users may find it beneficial to improve their requests     

掺铒光纤放大器中上转换过程的影响

掺杂浓度的提高影响了掺铒光纤放大器(EDFA)的性能,对经典Giles模型提出了新的要求。首先研究了高掺杂下铒离子距离较小引起的上转换过程的机理,通过优化速率方程模型分析了上转换过程对EDFA的影响,得出了在泵浦光和信号光远远大于ASE光的假设下泵浦光和信号光沿光纤长度变化的近似表达式,并将该近似分析解与解析解进行了比较。仿真结果表明上转换过程会降低随光纤传输的信号光和泵浦光,影响EDFA的放大性能,并得出了当掺铒浓度大于2.95×1025m-3时,上转换过程的影响不能忽略的结论。     

汉英成语和中西民族文化心理

成语的产生本质上也是一种化现象。它承载着民族化特色和化信息，包括民族化心理的信息。通过汉英成语看中西民族化心理的主要特征，并在进行比较的基础上，论述在跨化交际中成语与民族化心理的价值取向问题。     

对嗜好品风险认知的国际比较

对北京，大阪，洛杉矶3城市的市民就香烟和毒品的风险认知进行了抽样调查，并对其结果进行比较分析，主要结果如下：（1）中日美3国大约4／5的人对吸烟持负面性风险认知和评价，在3国中，美国人对吸烟的风险认知和危害性估计最高，中国居中，日本最低；（2）总体而言，中日美3国约9成以上的人对毒品持负面性风险认识和评价，在3国中，日本人对毒品的风险认知不安感最高，比较而言，美国人对毒品却表现出相对宽容的态度；（3）在3国中，日本人对香烟的社会容纳最高， 而对毒品的容纳度最低；美国人对毒品的社会容纳度远高于中国和日本；中国对香烟和毒品的社会容纳度都相对较低，这将有利于禁烟和禁毒。     

Pattern时延差编码四信道水声通信技术研究

本文所研究的是基于Pattern时延差编码（PDS）体制下的水声通信技术.PDS水声编码体制利用Pattern码片出现在码元窗的时延差值进行时延编码,通过码元分割,有效的降低了水声信道的多途干扰;通过频率分割划分四个通信信道,增加通信速率至1000bit/s.在接收端利用带通滤波器来实现通信信道分割,每个信道再应用拷贝相关器实现码元分割并估计出时延差值,完成译码.仿真实验表明,该系统适合于大量不同水声信道高可靠性工作,为水声通信网络化打下坚实基础.     

用正弦变频滤波器抑制孤子间的相互作用

提出用正统变频滤波器抑制孤子间的相互作用，并对上变频滤波器、下变频滤波器、交叉变频滤波器在抑制孤子相互作用方面的效应进行了数值研究。结果表明，正弦变频滤波器是最为有效的。     

基于EPP协议的便携机数据采集系统

设计了基于EPP协议的便携机数据采集系统 ,给出了技术解决方案。方案具有软硬件设计简捷、无需插卡等优点 ,可使外设工作于PC并行口的多种模式下。解决了线阵CCD图像采集系统与笔记本电脑之间的数据通讯 ,达到了便携数据采集的目的。     

平面机构运动数字化控制系统的设计

介绍了平面机构运动数字化控制系统的设计，其设计主要是对机械原理实验室中平面机构运动演示板进行改进，从原来的以单片机为控制核心到以微机系统为核心，系统控制本质是通过对解说语音文件的操作来达到对126个机构进行任意的操作，并且在性能上实现了易调试、可视化、多媒体等特点和功能，使教学效果得到显著提高，同时对于工业网络控制也具有一定的借鉴作用。