运动系统由骨、骨连接和骨骼肌组成。运动中,骨起杠杆作用,关节是运动的枢纽,骨骼肌是动力器官。骨和关节是运动系统中的被动部分,骨骼肌是运动系统的主动部分

• 7.1 金属的塑性成形工艺基础 • 7.1.1 金属的塑性成形 • 7.1.2 加工硬化和再结晶 • 7.1.3 塑性变形使金属形成纤维组织 • 7.1.4 金属的可锻性 • 7.2 金属的锻造 • 7.2.1 金属的锻前加热和锻成后冷却 • 7.2.2 自由锻造 • 7.2.3 模型锻造 • 7.2.4 胎模锻造 • 7.2.5 锻压零件的结构工艺性 • 7.3 板料冲压 • 7.3.1 冲压设备 • 7.3.2 板料冲压基本工序 • 7.3.3 冲模 • 7.3.4 冲压件的工艺性要求 • 7.4 金属的其它塑性成型方法 • 7.4.1 零件的轧制 • 7.4.2 零件的挤压 • 7.4.3 精密模锻 • 7.4.4 多向模锻 • 7.4.5 锻压新工艺技术简介

改善金属材料的性能,主要可以通过如下几种途径:合金化即加入合金元素,调整材料的化学成分。可显著媞高钢的强度、硬度和韧性,并使其具有耐蚀、耐热等特殊性热处理即金属材料通过不同的加热、保温和冷却的方式。使基内部的組结构发生变化,以达到改善加工工艺性前和强化力学性能的目的。 5.1 金属材料的改性处理理论基础 5.2 钢的热处理 5.3 钢的表面强化处理

Chapter Electronic Payment systems 10.1 Traditional Electronic Payment Systems for Electronic Commerce In electronic commerce, the challenges of payment transactions were initially underestimated Business via the internet and mobile telephony has so far been dominated by the methods of payment customary in traditional business. However, in light of technological progress

Chapter 12 Management of Electronic Commerce Security The business world has taken this to heart when it has come to the Internet. Companies have ventured onto the Information Superhighway in increasing numbers to \reduce distribution and marketing costs, eliminate the middleman, increase efficiency, promote impulse transactions and streamline distribution to far-flung locales\as well as to \connect directly with consumers at home, streamline operations and internal

Chapter 3 Technology of Electronic Commerce 3.1 A short history of the Internet and the web The Internet was the result of some visionary thinking by people in the early 1960s who saw great potential value in allowing computers to share information on research and development in scientific and military fields. J CR Licklider of MIT, first proposed a global network of computers in 1962, and moved over to the Defense Advanced Research Projects Agency(DARPA) in late 1962 to head the work to develop it Leonard Kleinrock of MIT and later UCLA developed

Chapter 5 Electronic commerce information's search and selection In physical markets, consumer search activities include reading advertisements, calling endors, and visiting stores. In a virtual marketplace, all these activities seem to converge into Web searches and Web browsing. Not surprisingly, search services are the first market infrastructure to be built in the electronic marketplace

Chapter 7 Internet marketing 7.1. Introduction of internet marketing 7.1.1 Internet marketing defined What is internet marketing? Internet marketing or internet-based marketing can be defined as the use of the Internet and related digital technologies to achieve marketing objectives and support the modern marketing concept. These technologies include the Internet media and other digital

Chapter 9 The principle of ebXML 9.1 The introduction of ebXML 9.1.1 What is ebXML? ebXML is a global electronic business standard that is sponsored by UN/CEFACT(United Nations Center For Trade Facilitation And Electronic Business)and OASIS(Organization for the Advancement of Structural Information Standards). ebXML thus defines a framework for global

浏览WWW World Wide Web简称W,也称万维网。 网页(Web页):浏览器中所看到的画面 Web站点:多个相关的Web页组合 Web服务器:放置Web站点的计算机