支持下一代无线宽带应用自适应QoS模型的研究

作为真正完整的下一代网络 ( NGN,Next Generation Network)解决方案 ,NGN需要在固定通信领域和移动通信领域都能够支持综合多媒体特性。NGN中的新一代移动通信网承载在开放式、层次化结构的分组交换网络之上 ,能够为用户提供端到端的 Qo S解决方案。本文分析了下一代移动通信系统中多媒体宽带应用的 Qo S问题 ,从无线通信系统的多层次结构出发 ,建立了业务流的 Qo S指标评判体系 ,为下一代网络中的无线宽带应用提供了一种自适应Qo S控制模型     

中国药典2005年版二部与2000年版收载眼科用药的对比

对比中国药典2005年版二部与2000年版二部中有关眼科用药方面的内容,简要归纳新增或未收载的品种与修改的内容。     

Decreasing miscibility with greater heterogeneity in ternary polymer blend: poly(cyclohexyl methacrylate), poly(α‐methyl styrene) and poly(4‐methyl styrene)

A ternary blend system comprising poly(cyclohexyl methacrylate) (PCHMA), poly(α‐methyl styrene) (PαMS) and poly(4‐methyl styrene) (P4MS) was investigated by thermal analysis, optical and scanning electron microscopy. Ternary phase behaviour was compared with the behaviour for the three constituent binary pairs. This study showed that the ternary blends of PCHMA/PαMS/P4MS in most compositions were miscible, with an apparent glass transition temperature (T_g) and distinct cloud‐point transitions, which were located at lower temperatures than their binary counterparts. However, in a closed‐loop range of compositions roughly near the centre of the triangular phase diagram, some ternary blends displayed phase separation with heterogeneity domains of about 1 µm. Therefore, it is properly concluded that ternary PCHMA/PαMS/P4M is partially miscible with a small closed‐loop immisciblity range, even though all the constituent binary pairs are fully miscible. Thermodynamic backgrounds leading to decreased miscibility and greater heterogeneity in a ternary polymer system in comparison with the binary counterparts are discussed. © 2003 Society of Chemical Industry     

灞河生态治理工程模型试验研究

通过模型试验 ,对位于西安市东郊因采沙使河道破坏严重的灞河河段进行了复现试验和研究 ,并以此为依据 ,通过优化比较为设计部门提供了合理的橡胶坝坝址和坝座高程。在此基础上 ,又对建坝后橡胶坝对上下游冲淤变化的影响进行了试验研究和分析 ,解决了工程设计中的一些关键技术问题     

Characterization of charge trapping in submicrometer NMOSFET's bygate capacitance measurements

Trapping of net positive charge at low gate stress voltage, and of net negative charge at high gate stress voltage, is observed through changes in the gate-to-drain capacitance of the stressed junction. These observations can be explained in terms of electron trapping, hole trapping, and generation of acceptor-like interface states located in the upper half of the bandgap. Channel shortening is also observed and found to exhibit a logarithmic time dependence     

微机传真系统

本文介绍了集传真技术、通信技术、微型计算机技术于一体的微机传真系统，提出了微机传真系统在硬件接口及报表识别上的实现方法。     

T_C≥400°C高温PTC陶瓷的研制

利用国产原料，采用传统的陶瓷材料制备工艺，研制了居里温度ＴＣ≥４００°Ｃ的高温ＰＴＣ陶瓷，制成了居里温度ＴＣ＝４１２°Ｃ，电阻Ｒ≤１０３Ω，ｌｇ（Ｒｍａｘ／Ｒｍｉｎ）＝４的高性能ＰＴＣ热敏陶瓷材料     

Urban radiowave propagation: a 3-D path-integral wave analysis

A discussion concerning the need for three-dimensional (3-D) urban radiowave propagation models is presented and followed by a review of previously published work on this topic using the asymptotic path-integral technique. The limitations and advantages of this technique are explained and it is applied to study diffraction by a small number of canonical geometries. The validity of this technique is verified by comparison with controlled laboratory measurements taken at millimetric wave frequencies. Finally, its ability to classify field components according to their distribution in space is employed in order to analyze the observed field strength distributions in the model environments