基于测量的接纳控制研究

与传统的接纳控制算法相比,基于测量的纳控制有诸多优点,首先它无需知识应用的流量模型,其次它能动态适应网络的负载变化,提高网络资源的利用率。文中分析了基于测量的接纳控制的基本思想,并在此基础上提出和实现了一种自适应的接纳控制算法（Adaptive Measurement-Based Admission Control,AMBAC).作者通过实验对该算法进行了验证,发现在系统资源利用率（或接纳能力）接近的情况下,与传统的（固定时间窗口的）,MBAC相比,AMBAC能达到更低的平均分组丢失率。     

空间元数据研究及应用

分布式地理空间数据的快速导航一直是分布式GIS研究的重点。针对地理空间数据的特点,在已有空间元数据标准的基础上,构造了一个分层空间元数据库框架,设计实现了不同级别的空间元数据库,很好地组织和管理了分布在网络上的地理空间数据库及其数据;在分层空间元数据库的支持下,基于地图（图层）的4个基本要素（专题、空间范围、地层、时间）,设计了一个面向用户的地理空间数据请求描述规范,并据此实现了一个基于多Agent的分布工地理空间数据查找策略,该策略能够很好地确定性或非确定性地理空间数据快速导航的要求。     

用VB实现Windows壁纸的自动更换

现给大家介绍一种户动更换壁纸的方法,它能使我们的桌面每次启动后都有“新感觉”。 我们知道注册表中关于壁纸的主键为ＨＫＥＹ　ＣＵＲ－ＲＥＮＴ　ＵＳＥＲ＼Ｃｏｎｔｒｏｌ Ｐａｎｅｌ＼Ｄｅｓｋｔｏｐ,相关键值名有三个,即Ｗａｌｌｐａｐｅｒ：设置壁纸,其值为壁纸图像文件名;Ｗａｌｌｐａｐｅｒ－Ｓｔｙｌｅ：设置用于填充壁纸周围剩余空间的Ａｃｔｉｖｅ Ｄｅｓｋｔｏｐ样式;Ｔｉｌｅ　Ｗａｌｌｐａｐｅｒ：设置壁纸的显示方式。 更换壁纸只需更改相应的键值即司。实际上,Ｗａｌｌｐｐａ－ｐｅｒＳｔｙｌｅ和ＴｉｌｅＷａｌｌ…     

基于Web的数据库应用系统的接口技术探讨

本文对目前流行的几中Ｗｅｂ数据库接口方式作了较深入的分析,并给出了一般性的选择建议,最后对Ｗｅｂ ＤＢ系统的发展邮自己的看法。     

Analysis of a mixed mode fracture specimen: the asymmetric double cantilever beam

An asymmetric double cantilever beam (ADCB) is a simple but effective specimen for the measurement of polymer/polymer and polymer/non-polymer bimaterial interface fracture toughness. In order to characterize fully the bimaterial interface strength, and to control the crack trajectory, the critical energy release rate, G _c, and the phase angle, , of the applied stress field as functions of loading and geometry of the specimen should be obtained. For most practical cases, has to be evaluated numerically. In this work, a boundary element analysis is carried out to obtain G and for the ADCB specimen at different material and geometry combinations. An expression for the energy release rate, G, based on Kanninen's beam on elastic foundation model is compared with the numerical results. Limitations on the use of the ADCB specimen are also discussed.     

Initial high beta operation of the HBT-EP Tokamak

HBT-EP is a new research tokamak designed and built to investigate passive and active feedback techniques to control MHD instabilities. In particular, HBT-EP will be able to test techniques to control fast MHD instabilities occurring at high Troyon-normalized beta, _N Ba/I_p [Tm/MA], since it is equipped with a thick, close-fitting, and adjustable conducting shell. The major goals of the initial operation of HBT-EP have been the achievement of high beta operation (_N 3) using only ohmic heating and the observation of MHD instabilities. By using a unique fast startup technique, we have successfully achieved these goals. A variety of MHD phenomena were observed during the high beta operation of HBT-EP. At modest beta (_N 2), discharges have been maintained for more than 10 msec, and these discharges exhibit saturated resistive instabilities. When _N approaches 3, major disruptions occur preceded by oscillating, growing precursors. During start-up, one or more minor disruptions are usually observed. A 1-D transport code has been used to simulate the evolution of the current profile, and these early minor instabilities are predicted to be double tearing modes. The simulation also reproduces the observed high beta operation when saturated neo-Alcator energy confinement scaling is assumed.     

盘/轴系统瀑布图的仿真

介绍了以MATLABV5 2为平台开发的盘 /轴系统瀑布图的仿真程序 ,仿真的结果可为设计和调整系统参数提供直观 ,可靠的依据。     

近期美国乙烯市场综述

综述了近期美国乙烯的供应与需求状况，回顾了近期乙烯价格走势，分析了美国乙烯市场变化的影响因素。     

石榴石中Cr^3＋的电子结构与晶场强度的关系

本文对掺铬的GGG(Ca,Mg,Zr),GGG,YGG和YAG四种晶体进行了自旋极化的SCC-DV-X_α计算。首次报道了它们的10Dq计算值,与实验值符合得很好,并讨论了中心离子和配位体之间的距离与该计算值的关系。还计算得到了二重态~2E_3的能量值,从而阐明了YAG_2cr~(3+)只能发射窄带荧光,而GGG(Ca,Mg,Zr):Cr~(3+)能发射强的宽带荧光的机理。     

纳米粉体在涂料中的应用(Ⅰ)

简述了纳米微粒的基本性质,初步探究了纳米粉体应用在涂料中对其性能的改善,介绍了几种特殊功能的纳米涂料,提出了纳米粉体在涂料应用中存在的一些问题,如纳米微粒的表面改性、添加量的影响、成本的降低等。