宽带接入的春天还有多远

中国宽带业务的发展面临诸多问题:内容建设严重滞后于网络建设、缺少盈利的“杀手”业务、服务水平尚未达到宽带需求、恶性竞争产生网络泡沫以及产业环境尚不完善等。要想改善现状,宽带接入建设应采取下列措施:借助政府力量、联合社会力量、准确定位市场、丰富接入手段以及加强技术培训等。     

基于SIP协议的IP电话增值业务实现技术

讨论了SIP协议以及基于SIP协议的IP电话增值业务实现技术 ,并对SIPCGI、CPL、SIPServlets、JAINAPIs等几种SIP编程技术进行了分析与比较 ,归纳总结了开发IP电话增值业务的一般方法     

Ubiquitous Information Services with JAIN Platform

To provide responsive information services in a ubiquitous computing environment, service software and system development are indispensable. A component-based ubiquitous information system with a JAIN (Java APIs for Integrated Networks) platform to achieve seamless transmissions and reach-everywhere communications was designed in our research. In this development, numerous ubiquitous service modules were identified: location management, roaming, mobile IP and WAP networking. These component-based network modules were constructed using a component composition language with component specification and interface definition, running on top of a distributed service architecture using a JAIN platform to distribute the ubiquitous information services to mobile users. Two applications, Wireless-Application-Protocol (WAP) Mail and Video-on-Demand (VoD) services, show that the JAIN-like platform with the developed networking components effectively fills the gap for application developers between mobile appliances and various kinds of ubiquitous information services.     

奥地利移动通信市场

移动通信市场已经成为奥地利竞争程度较高的市场,主要的4家移动运营商分别是Mobilkom,Max.Mobil,Connect Austria和Tele.ring,其中Mobilkom占有的市场份额最大,奥地利政府于2000年11月拍卖了6张国内3G许可证,除了上述4家运营商获得3G许可证之外,奥地利Hutchison 3G和3G Mobile也得到了3G牌照.     

CDMA位置服务系统的本地定位平台建设

移动位置业务是移动通信网络的一项特色增值业务．将成为今后几年的业务增长亮点之一。中国联通总部的增值业务部于2002年采用集中设置方案，进行了CDMA位置服务系统一期工程的建设。本地定位平台建立于中国联通CDMA位置服务系统基础之上．其功能由以下的一项或多项组合而成：门户功能、中间件功能、GIS系统的的功能和对本地的CP进行管理和计费的功能。     

对高校图书馆参考咨询服务的探讨

面对现代信息时代的挑战，高校图书馆参考咨询服务进行着深刻的变革，其系统化、网络化、合作化、社会化、高效化是这种变革的集中体现。     

New intramolecular effect observed for polyesters: An anomeric effect

A series of polyesters was prepared to evaluate hydrolytic stability as a function of cyclohexyl dibasic acid content. The three cyclohexyl dibasic acids: 1,2; 1,3; and 1,4 were formulated into polyesters with two glycols. The proportion of cis and trans isomers was evaluated via ¹H NMR. The hydrolytic stability of short chain polyesters was evaluated in an acetone/water mixture which solubilized the polyesters to mimic oligoester behavior within a thermosetting polyester coating environment. The rate of hydrolysis was monitored by acid titration and corroborated by GPC. Surprisingly, 1,2-cylohexyl diacid-based polyesters were robust, and 1,3-cyclohexyl diacid-based polyesters were the most susceptible to hydrolysis. Evidently, a 1,2-anchimeric effect for cyclohexyl dibasic acid polyesters was not an important consideration, while the 1,3-cyclohexyl ester interaction was. Consequently, an anomeric effect was proposed. Presented at the 81st Annual Meeting of the Federation of Societies for Coatings Technology, November 12–14, 2003, in Philadelphia, PA.     

标准咨询服务探讨

通过对标准化咨询服务各种模式的具体阐述，论证了其对企业发展的重要作用，以及信息化在标准服务中的的重要地位。