Rain induced cross polarization at millimeter waves in a Xi'an environment

The rainfall intensity accumulative distribution, raindrop size and canting angle distributions in Xi'an(108.9 E, 34.3 N) have been obtained from data measured over a long period of time. Rain induced crose polarization in this environment has been studied. The crose polarization discrimination, XPD, was compu ted over a frequency range of 19.3 to 300 GHz for non spherical drops. The variations of XPD with frequency, rainfall rate and copolar attenuation, CPA, were investigated. The computational resulte are in good agreement with experimental data. A mathematical relationship was established between the XPD and CPA, raindrop canting angle, which result is in good agreement with experimental data. The cumulative distribution of rain induced cross polarization for eleven years and in month have been ob tained with the cumulative distribution of the rain rate from the data measured from 1975 to 1985. The role of multiple scattering also has been discussed, it is shown that the multiple scattering play an important part in short millimeter wave.     

微带印刷天线辐射与散射的全波分析方法

本文给出了一种分析微带印刷天线辐射与散射的数值方法。此方法将印刷天线按三角网格剖分，在导体表面建立积分方程，用全波离散镜像理论给出微带结构的空域格林函数的闭合表达式，未知电流用三角网格上的矢量电流基函数展开并用矩量法求解。与以往的矩形网格上基函数展开相比，此方法能更有效地逼近任意形状的微带结构，最后给出了几个数值结果     

LIGA技术的掩模制造

ＬＩＧＡ技术是近几年才发展起来的一门新的技术，包括光刻、电铸和塑铸。由于要进行深度Ｘ光曝光，所用的同步辐射Ｘ光较硬，这一曝光条件相应就需要Ｘ光掩模吸收全有较大厚度和较高的加工精度，这样才能够阻档住Ｘ光，同时保证较高的光刻精度。     

A fault-tolerant protocol for election in chordal-ring networkswith fail-stop processor failures

In a distributed computer system, a group of processors is connected by communication links into a network. Each processor (node) of the network has an identity (a unique integer value) that is not related to its position in the network (its address). A processor's identity is known only to the processor. In the problem of leader election, exactly one processor among a network of processors has to be distinguished as the leader. Previously, many efficient election protocols have been proposed for networks with a sense of direction. In particular, the sequential search is used for election in a reliable complete network, and a multi-token search method is used in a faulty complete network. However, election protocols on a faulty ChRgN (chordal ring network) have not been investigated by other researchers. This paper addresses this issue by: studying the problem of leader election in an asynchronous ChRgN with a sense of direction and with the presence of undetectable fail-stop processor failures; proposing a new election protocol which (a) combines the concept of sequential search and multi-token search techniques, and (b) uses an efficient routing algorithm to reduce the total number of messages used; presenting a protocol for a ChRgN of n processors with I chords/processor and at most f fail-stop faulty processors, with message complexity O(n+(n/l)log(n)+k·f), where k is the number of processors starting the election process spontaneously and at most f相似文献   

交互电视与应用

交互电视（ITV）是一种基础结构。这种结构提供了为数众多的硬件、软件和应用平台，这一点很像INTERNET。INTERNET也是一种结构，在它的上面有很多的硬件（服务器、客户机、调制解调器）、软件（WWW浏览器、WWW服务器程序、电子邮件服务器、通讯协议）和服务（FTP、电子邮件、新闻组、WWW）。     

纳米金刚石用做润滑添加剂的研究进展

纳米粒子做润滑油添加剂表现出良好的摩擦学性能。纳米金刚石由于同时具备金刚石和纳米材料的双重优异特性,很多研究人员将其作为新型减摩抗磨添加剂应用于润滑剂。应用中的关键问题是对纳米金刚石团聚体进行表面改性,实现纳米金刚石在油体系中的解团聚和稳定分散。文章综述了对纳米金刚石进行表面改性的研究进展,总结了纳米金刚石作为润滑添加剂的特点及其摩擦学机理,提出了需要更进一步深入研究的方面。     

我国 FFS 袋用吹塑薄膜发展动态

介绍了生产连续性一次自动成型-开口充料-加热封口（FFS）袋用吹塑薄膜的平膜法和管膜法工艺及三层共挤膜技术，概述了国内FFS袋用吹塑薄膜的生产企业和原料使用情况。FFS袋用吹塑薄膜具有包装速度快、洁净、环保、美观等优势，随着国内合成树脂装置生产规模的扩大，FFS袋用吹塑薄膜将替代传统复合编织袋成为合成树脂包装领域的主导产品。     

单井注水吞吐在塔河油田的应用

在塔河油田开发生产过程中，个别油井在修井作业中出现先漏后喷的现象。在修井完成后，产量较前期有大幅增加。针对这类油井进行单井注水吞吐采油试验，研究发现钻遇定容封闭性油藏的油井适合单井注水吞吐开采。一方面利用油水重力分异，抬升油水界面，增加采出量；另一方面注水补充地层能量，恢复地层压力。该方法在塔河油田实际应用中，取得了较好的效果和较高的经济效益，也为提高定容封闭性油藏油井的采收率提供了一个较好的方法。     

火成岩油藏特征及其测井响应

系统的阐述了火成岩的生成机制及其构造,结合其石油储存条件,分析得出火成岩油气藏的分布特征,成藏机制。并以塔里木油田和辽河油田对火成岩的勘探为实例,从测井分析角度阐述了火成岩的油气藏的勘探开发成果,尤其是塔里木油田的英买地区及辽河坳陷都在火成岩的部分岩层见到良好的油气显示。这说明与火成岩相关的油气聚集将成为石油勘探开发的一个具有很大潜力的新领域。