一种拨号接入Internet的技术方案

本文分析了拨号接入Ｉｎｅｔｎｅｔ方式的优点，核心技术和软件要求，介绍了北方电讯Ｒａｐｐｏｒｔ拨号接入交换机系列ＤＳ８Ｅ／８Ｔ、ＤＳ１１２和ＤＳ６７０的功能和应用。     

浅谈中国电信网络管理

本文介绍了全国电话网管系统及各专业网管系统的和实施情况，分析了中国电信网管系统的特点，现状和走向，指出了网管在整个电信网运行维护管理工作中的龙头地位。     

设计模式在软交换软件系统中的应用

设计模式针对面向对象系统中重复出现的设计问题，提出一个通用的设计方案并予以系统化，其具体种类包括Abstract Factory,Chain of Responsibility,Iterator,Observer,State,Strategy等，一旦设计模式应用到软交换软件系统设计中，就可以在寻找合适的对象，指定对象接口，运用复用机制，支持设计变化等方面提供帮助，设计模式在软交换软件系统中的具体应用包括通过Strategy实现计费策略等。     

青海省电信公司普遍服务概况

青海省电信公司一直担负着青海省的普遍服务义务,多年来取得了一定的成绩。如已具备较为齐全的业务种类、遍布全省的服务网点、多样化服务手段和低廉的服务资费等,也达到了一定的电信服务普及率。但由于青海地处边陲,经济发展相对落后,实施普遍服务也有许多困难。如消费水平低、运营商长期亏损;投入大、回收慢;线路长、维护成本高等。运营商的意愿是尽快建立普遍服务补偿机制、取消不对称管制、在资费上给于一定的自主权等。     

南京公共宽带IP城域网建设实践

为了突破信息高速公路最后一公里的瓶颈,南京电信局于１９９９年建设成了“超级金陵热线”宽带ＩＰ试验网,目前已完成了网络架构的搭建、设备的互通性测试、应用业务的测试、小区的规划与设备改造以及网络安全策略的确立。在此基础上,南京电信局确立了２０００年宽带ＩＰ网建设项目ＢＩＰ－２０００,建设南京公众宽带ＩＰ城域网。     

具有无损耗缓冲电路的软开关双管正激式变换器

介绍了一种具有无损耗缓冲电路的软开关双管正激式变换器。它采用无损耗缓冲技术,使开关管工作在软开关状态,抑制了dv/dt,使开关管的开关损耗下降一半左右。同时缓冲电路本身并不消耗能量,而是将能量返回到系统中,提高了整机效率。文中对其工作原理,缓冲电路的能量转换过程进行了分析,并给出了实验结果及波形。     

谈谈智能化通信用开关电源与蓄电池的检测

市电中断后,正确预告蓄电池放电的剩余容量,一直是电信运行部门追求的目标。文中主张在通用高频开关电源中增加蓄电池监测设备,组成一个智能化的电源系统,能够在市电中断时预告蓄电池的放电剩余容量。这在实际应用中可以提高系统的可靠性并方便使用。     

浅谈通信电源的浪涌抑制

通信电源设备因浪涌造成损坏（特别是模块级SPD损坏）的比例仍较高,尽管大多数通信电源系统安装了SPD,但从实际使用情况来看不够理想。因此,针对目前通信电源防雷方案在实际使用中出现的问题,分析原因,并提出了改进方法。     

Metal compound-mediated hydrolytic cleavage of oxidized insulin B chain:Regioselectivity and influence of peptide secondary structure

The interaction of oxidized insulin B chain(B)with cis-[Pd-(en)Cl2](en=ethylenediamine),cis-[Pd-(dtco-3-OH)Cl2](dtco-3-OH=dithiacyclooctan-3-ol)and CuCl2 was studied by electrospray inass spectrometry.It is discovered that the binding of Pd(Ⅱ)complexes and the sites of cleavage are highly dependent on the secondary structure and local environment of B.The hydrolytic cleavage of denatured B by Pd(Ⅱ)complexes was monitored by HPLC.The reaction is regioselective and follows first order kinetics with half-life of 4.8 days at 40℃.Two amide bonds,i.e.at Leu6-Cys7 and at Gly8-Ser9,which are close to the two potential Pd(Ⅱ)binding sites His5 and His10,are selectively cleaved.In the case of Cu(Ⅱ)ion as promoter,only one cleavage site was observed which is located at Gly8-Ser9 bond.These results provide improved understanding on the design of artificial metallopeptidase.     

Structure and electrospray mass spectrometry studies on dithiacyclooctan-3-ol-containing palladium (II) complex of trans -[Pd(dtco-3-OH)_2](ClO_4)_2·2DMSO

The structure of trans-[Pd(dtco-3-OH)2] (ClO4)2·2DMSO, in which dtco-3-OH is dithiacyclooctan-3-ol and DMSO is dimethyl sulfoxide, was determined by X-ray crystallographic analysis. The crystal data: space group pi, a = 0.7077(2) nm, b = 1.0788(1) nm, c = 1.1111(1) nm, α=67.710(8)°, β = 73. 59(2)°, γ = 85. 39(2)°,R1 = 0 . 0368 and Rw = 0.0998. The palladium (II) is coordinated by four sulfur atoms with a regular square planar configuration. The Pd-S distances are 0.2314(1) and 0.2317(1) nm, respectively. Both dtco-3-OH ligands are in the boat-chair configuration and two hydroxyl groups are on the opposite sites of the PdS4 coordination plane and are towards Pd(II). The Pd-O distance is 0. 285 nm, indicating a weak interaction between them. A typical hydrogen bond between the hydroxyl group of dtco-3-OH ligand and DMSO was observed in the crystal structure. An aqueous solution prepared with the crystals of the complex was used for the investigation of electrospray mass spectrometry ( ESMS ). Besid