三、分组交换与路由 1.广域网的结构 2.编址与分组交换 3.路由问题 4.常用广域网

1.广域网的通信线路与接入技术 2.包交换机与路由器工作原理 3.再谈网络的灵魂,网络的语言——协议(实现异构网络的连接)

1.不同类型的局域网,不同的用途Ethernet; FDDI; ATM; 无线网 2.不同类型的局域网,异构的;如何连接? 3.如何构造Ethernet局域网?总线式集线器 交换式集线器; 4.Ethernet的工作原理(CSMA/CD)组建后的局域网,如何应用?

数字声音的特点：是一种连续媒体，传输与播放有实时性要求数据量大，对存储和传输的要求很高。数字声音的类型：

一. 二进制 1.二.八.十六及各种进制.进制的本质?为什么要用二(八.十六)进制？ 2.各种进制之间的转换 (2,8,16,x)进制转换为10进制 10进制转换为(2,8,16,x)进制

一、组成： 计算机系统由硬件与软件组成 硬件：物理装置的总称 软件：程序+数据+文档

There is a group of compounds in which carbon forms only two bonds. These neutral divalent carbon compounds are called carbenes. Most carbenes are highly unstable compounds that are capable of only fleeting existence. Soon after carbenes are formed they usually react with another molecule

1. The experimental conditions — temperature and acid concentration — that are required to being about dehydration are closely related to the structure of the individual alcohol. The relative ease with which alcohols undergo dehydration is in the following order:

SN2 reactions are highly useful in organic synthesis because they enable use to convert one functional group into another —— functional group transformation (functional group interconversion)

The C—X bond of alkyl halides is polarized. The carbon atom bears a partial positive charge, The halogen atom a partial negative charge