网络计费系统的主要技术及ASP实现——LAN用户基于IP流量上网计费

介绍了开放实验室实现网络计费的背景和网络计费的解决方案,着重介绍了网络计费软件的主要组成部分及其关键技术,并探讨了开发针对局域网用户帐户按照IP流量进行上网计费系统的有关问题。     

Overview of a Modal-Based Condition Assessment Procedure

Condition assessment is a term that is used to describe the process of characterizing the physical condition of constructed systems. This paper summarizes a condition assessment (CA) procedure based on a complete system of field-testing, finite element (FE) modeling, and load rating. Experimental techniques, including both modal testing and truckload testing, are used to collect measurements of the constructed systems. The basic mechanism and procedure of the FE modeling and calibration are presented. Different physical parameters of FE models are adjusted during the calibration process using both static and dynamic responses as criteria to achieve convergence between experimental measurements and analytical results using carefully developed objective functions. Finally, a bridge load rating is completed on the basis of the calibrated model. These developments are described and illustrated using a representative bridge as an example.     

电网联合反事故演习技术支持系统

从调度运行的角度介绍了陕西省电力调度中心参加2002年西北电网联合反事故演习中技术支持系统(电网仿真系统、网上直播系统、通讯系统、视频系统)各部分的功能及配置.     

Photoreflectance Spectroscopy for Study of Si/SiGe/Si Heterostructure

UHVCVD-grown Si/Si1- xGex/Si heterostructure was investigated by Photoreflectance spectroscopy (PR). The principle of PR used in semiconductor film was thoroughly described. According to the E1 transition energy in the Si1- xGex alloy, the Ge content in SiGe film with constant composition can be accurately characterized. In this study, determine the composition uniformity of larger diameter SiGe epiwafer by PR mapping technique was determined. These results show PR is very promising for Si1- xGex epilayer characterization with constant Ge content and can provide film measurements for production-worthy line monitor.     

Effect of Ion Dose on Growth of Relaxed SiGe Layer on Ion Implantation Si Substrate

Thin strain-relaxed Si0.8Ge0.2 films (57.6 nm) on the 30 keV Ar ion implantation Si substrates for different dose (1 × 1014, 5 × 1014, 3 × 1015 cm-2) were grown by ultra high vacuum chemical vapor deposition (UHVCVD) system.Rutherford backscattering/ion channeling (RBS/C), high resolution X-ray diffraction (HRXRD), Raman spectra as well as atomic force microscopy (AFM) were used to characterize these SiGe films. Investigations by RBS/C as well as HRXRD demonstrate that these thin Sio.8Geo.2 films could indeed epitaxially grow on the Ar ion implantation Si substrates. Under low dose ( 1 × 1014 cm-2) and medium dose (5 × 1014 cm-2) implantation conditions, the relaxation extents of SiGe films are 60.6% and 63.6%, respectively. However, high dose implantation (3 × 1015 cm-2) prompt the strain in epitaxial SiGe film to be close to full relaxation status (relaxation extent of 96.6% ). On the other hand, determinations of RBS/C also indicate the crystalline quality of SiGe film grown on high dose implantation Si substrate is nearly identical to that grown on low dose (1 × 1014 cm-2) implantation Si substrate.     

行人惯性导航系统平台设计与实现

为了满足日益迫切的个人自主导航需求,设计具有实时导航功能的行人惯性导航系统平台。系统平台由搭载低成本MEMS(Micro Electro Mechanic System)惯性器件的硬件平台和基于VC编写的上位机软件平台组成。重点研究行人导航算法、系统平台搭建、传感器在线标定和信息实时处理。多次行走实验的实时导航误差均在2%以内,证明该导航系统平台在不依赖于外界信息的情况下具有良好的实时自主导航性能。     

基于ARM的PCMCIA接口设计

嵌入式系统在网络控制和通信领域有着越来越广泛的应用。本文通过分析PC卡时序,利用ARM处理器S3C4510B和外部电路设计PCMCIA接口,实现与无线网卡的软、硬件接口,从而可以使用基于ARM的嵌入式系统来开发无线网络产品。     

Na0.5Bi2.5Nb2O9-Na0.5Bi4.5Ti4O15材料的微观结构及电性能

采用固相烧结法制备了铋层结构铁电材料(1-x)Na0.5Bi2.5Nb₂O₉-xNa0.5Bi4.5Ti₄O₁₅(NBNO-NBT-x)。结合XRD、SEM以及电子能谱分析推测NBNO-NBT-0.5陶瓷主要为2-4层的共生结构NaBi₇Ti₄Nb₂O₂₄,由Na0.5Bi2.5Nb₂O₉和Na0.5Bi4.5-Ti₄O₁₅沿c轴交替排列。晶格结构的不对称性增加导致晶格应力增大,而NBNO和NBT两种单体系的复合将进一步加大离子无序和结构无序,从而使该组成的陶瓷表现出不同于两种单体系的微观结构和电性能。NBNO-NBT-0.5陶瓷的晶粒长度大于20 μm,厚度小于2 μm,晶粒长径比明显高于NBNO和NBT;而相比于两种单体其居里温度TC降低,居里峰宽化,高温介电损耗增大,电导激活能减小,铁电、压电性能降低。     

基于支持向量机的模拟电路故障诊断研究

针对模拟电路的故障诊断问题,详细介绍了支持向量机算法,由于它在非线性映射、小样本学习方面的独特优势,故将它引用到模拟电路的故障诊断过程中.并提出了一种基于支持向量机的诊断方法,该算法能够对被测电路的故障进行有效并且精确地分类.以折线逼近平方曲线的近似测量电路为例,设计了基于支持向量机的模拟电路故障诊断系统.以实际测试数据作为训练样本进行学习训练后,对其它实际测量数据进行诊断,其结果正确,验证了算法的有效性.     

基于抗扰动-模糊PID的污水处理控制方法研究

针对序批式活性污泥法(SBR,Sequencing Batch Reactor)污水处理过程具有的非线性、时变、强耦合等特性,并考虑污水处理过程控制存在入水水质流量等干扰量,进一步加大控制难度等问题,本文提出1种扰动观测器与模糊PID结合的污水处理控制方法。首先分析扰动观测器结构特点以及核心部分低通滤波器的选择,设计扰动观测器对控制过程常见干扰量进行预测,并根据预测扰动信号在控制系统输入端进行有效补偿,达到抵消干扰的效果:同时在此基础上结合模糊PID控制方法,自适应整定PID控制器参数,实现溶解氧DO的优化控制。最后建立仿真模型进行实验,并与常规PID控制和模糊PID控制效果进行对比,结果表明该组合控制方法能有效克服干扰,控制精度较高,具有较强的适应性和鲁棒性。