宽带接入服务器的选择配置和应用

本文主要分析了影响宽带接入服务器性能的各种因素，介绍了如何选择宽带接入服务器，并针对REDBACK公司的SMS1800和UNISPHERE公司的ERX1400两种典型宽带接入服务器说明如何进行配置，为应用宽带接入服务器提供参考。     

Hankel transform-domain analysis of scattered fields in multilayer planar waveguides and lasers with circular gratings

Radiation patterns of scattered fields with arbitrary azimuthal orders in multilayer planar waveguides and laser cavities with circularly symmetric gratings are formulated based on the volume current method. Full-wave Green's function analysis based on the integral transform method lies at the heart of this approach. Unlike the conventional approach, the dyadic Green's function relates some auxiliary fields to some auxiliary sources in the spectral domain. These auxiliary functions are defined to facilitate the spectral domain formulation in the cylindrical coordinate system and the use of transfer matrix method for obtaining a closed-form solution of the spectral Green's function in multilayer planar structures. More importantly, it is shown that the far-field pattern of the scattered field can be expressed directly in terms of the auxiliary fields in the Hankel transform domain.     

走向IMS的PS域核心网规划建设方案

在3G牌照正式发放之前，我们仍然需要为新一轮大规模网络建设继续做准备。3G网络和现有2G网络如何互连互通，数据用户如何在3G网络和2G网络之间进行无缝连接，如何使系统网络方便地演进到IMS构架，这些问题都需要大家思考。一个经济有效且易于演进的网络结构，将对运营商顺利开展新一代移动业务，快速抢占发展的制高点，起到相当关键的作用。     

用两亲聚合物制备大颗粒苯丙乳液

分别以两亲聚合物P(C9-AA)和P(DCPD-St-α-St-AA)作乳化荆，研究了制备大颗粒(约1μm)及具有一定稳定性的苯丙乳液的方法，讨论了乳化剂，温度及引发剂用量对乳液性能的影响。结果表明，以P(C9-AA)作乳化剂时，引发剂用量为单体质量的1．2％，90℃时可以合成性能良好的苯丙乳液；以P(DCPD-St-α-St-AA)作乳化荆时，引发剂用量为单体质量的1．2％，80℃时可以合成性能良好的苯丙乳液。     

基于智能模糊控制策略的有源消声

有源消声是一种有效的低频噪声控制方法，由于空间有源消声过程具有时变性和非线性，传统的自适应算法不能进行很有效的控制。本文采用智能模糊控制策略，建立了基于智能模糊控制策略的有源消声系统，通过实验与传统自适应控制算法的消声效果作对比分析，证明智能模糊控制器不但控制速度快，易于实现，而且消声效果明显优于后者，具有较大的应用推广价值。     

High concentration erbium doping of silicon-rich SiO2 thin films on silicon

In this work, high concentration erbium doping in silicon-rich SiO₂ thin films is demonstrated. Si plus Er dual-implanted thermal SiO₂ thin films on Si substrates have been fabricated by using a new method, the metal vapor vacuum arc ion source implantation with relatively low ion energy, strong flux and very high dose. X-Ray photoelectron spectroscopy measurement shows that very high Er concentrations on the surfaces of the samples, corresponding to 10 at.% or the doping level of 10²¹ atoms cm⁻³, are achieved. This value is much higher than that obtained by using other fabrication methods such as the high-energy ion implantation and molecular beam epitaxy. Reflective high-energy electron diffraction, atomic force microscopy and cross-section high-resolution transmission electron microscopy observations show that the excess Si atoms in SiO₂ matrix accumulate to form Si clusters and then crystallize gradually into Si nanoparticles embedded in SiO₂ films during dual-ion implantation followed by rapid thermal annealing. Er segregation and precipitates are not formed. Photoluminescence at the wavelength of 1.54 μm exhibits very weak temperature dependence due to the introduction of Si nanocrystals into the SiO₂ matrix. The 1.54-μm light emission signals from annealed samples decrease by less than a factor of 2 when the measuring temperature increases from 77 K to room temperature.     

机车紧急制动装置使用中的几个问题

针对机车紧急制动装置使用中出现的问题进行了分析，并提出了几点解决问题的方法，对今后紧急制动装置的设计和使用具有一定的参考价值。     

RBF neural networks-based robust adaptive tracking control for switched uncertain nonlinear systems

In this paper, a robust adaptive H∞ control scheme is presented for a class of switched uncertain nonlinear systems. Radical basis function neural networks (RBF NNs) are employed to approximate unknown nonlinear functions and uncertain terms. A robust H∞ controller is designed to enhance robustness due to the existence of the compound disturbance which consists of approximation errors of the neural networks and external disturbance. Adaptive neural updated laws and switching signals are deducted from multiple Lyapunov function approach. It is proved that with the proposed control scheme, the resulting closed-loop switched system is robustly stable and uniformly ultimately bounded (UUB) such that good capabilities of tracking performance is attained and H∞ tracking error performance index is achieved. A practical example shows the effectiveness of the proposed control scheme.     

评《清闲供、小蓬莱》

我国古典园林论著,现在常见的有计成的《园冶》、李笠翁的《一家言居室器玩部》以及明人程荩臣的《清闲供》书中的《小蓬莱》共三种,其余零星散见于古人笔记的不计。《清闲供》一书,计有不同内容的短篇十四篇,《小蓬莱》谈造园艺术,只是书中的一项内容,全文短。《清闲供》毫无现实的积极意义,经过时代的淘汰更失去其效用,成为了糟粕。