Electronic Commerce Prentice Hall © 2006 2 Learning Objectives 1. Describe the B2B field. 2. Describe the major types of B2B models. 3. Discuss the characteristics of the sell-side marketplace, including auctions. 4. Describe the sell-side intermediary models. 5. Describe the characteristics of the buy-side marketplace and e-procurement. 6. Explain how reverse auctions work in B2B

Electronic Commerce Prentice Hall © 2006 2 Learning Objectives 1. Define e-marketplaces and list their components. 2. List the major types of e-marketplaces and describe their features. 3. Describe the various types of EC intermediaries and their roles. 4. Describe electronic catalogs, shopping carts, and search engines

核酸是遗传物质 1868 年瑞士Miesher.从脓细胞的细胞核中分离出可溶于碱而不溶于稀酸的酸性物质。 间接证据：同一种生物的不同种类的不同生长期的细胞，DNA含量基本恒定。 直接证据：T2噬菌体DNA 感染E.coli 用 35S 标记噬菌体蛋白质，感染E.coli，又用 32P 标记噬菌体核酸，感染 E.coli DNA、RNA的分布（DNA 在核内，RNA 在核外）

E.使用UIDL在ANSYS主菜单中增加一个菜单项，点击后可以出现一个子菜单或激活一个对话框。 APDL E. 使用APDL编制一个可以读写有限元模型的小程序，要求读出所有节点号和单元号，节点坐标以 及单元节点列表。 E. 使用DNSOL，DESOL定义计算结果

一、消去反应机制 消去反应的机理 —— E1, E2, and E1cB

z 无向图(undirected graph) 哥尼斯堡七桥 Euler 图 无向图，简称图，是一个用线（边）连接在一起的节点（顶点）的集合。严 格地说，图是一个三元组 G=( V, E, I ), 其中，V 是顶点的集合，E 是边的集 合，而 I 是关联关系，它指明了 E 中的每条边与 V 中的每个顶点之间的关联关 系：每条边必定连接两个而且只有两个顶点，它们称为该边的端点

1 The eigenvalue distribution function For an N × N matrix AN , the eigenvalue distribution function 1 (e.d.f.) F AN (x) is defined as F AN (x) = Number of eigenvalues of AN ≤ x . (1) N As defined, the e.d.f. is right continuous and possibly atomic i.e. with step discontinuities at discrete points. In practical terms, the derivative of (1), referred to as the (eigenvalue) level density, is simply the

Theory of Equivalence Relations (A, R) (E1) For all x : xRx. (E2) For all x, y : If xRy then yRx. (E3) For all x, y, z : If xRy and yRz then xRz. Logic in Computer Science – p.2/16

I．Choose the Correct Answer 1. A disturbance can be written x b xt b t a y(x,t) (e e e ) 2 2 −( / ) 2 / − = . This disturbance is （ D ） (A) Not a traveling wave. (B) A traveling wave with speed v = a. (C) A traveling wave with speed v = a/b. (D) A traveling wave with speed v = b

第7章图 7.1图的定又和木语 1、图、顶点、边 图G是由集合V(G)和E(G)组成,记为G=e),其中V(G)是顶点的非空有限集合,E(G)是边的有限集合,边是点的无序对或有序对