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ch04-活动目录的逻辑结构和物理结构

2019/12/13
第四章活动目录的逻辑结构和物理结构
5
网络构建与管理
4.1.1 活动目录的基本概念
目录服务的由来目录服务是基于X.500的规范的。用于存储、分发和访问用户信息。采用分布式信息存储。将物理位置分散的网络资源集中起来进行管理。
2019/12/13
第四章活动目录的逻辑结构和物理结构
15
网络建与管理
4.1.1 活动目录的基本概念
属性属性用来描述对象。每一个属性都拥有它自己的
定义，定义则描述了特定于该属性的信息类型。架构中的每一个属性都可以在“AttributeSchema”分类中指定，该分类决定了每一个属性定义所必须包含的信息。
注意：每一个属性仅仅定义一次，但是可以在多个分类中使用。
6
网络构建与管理
4.1.1 活动目录的基本概念
目录服务的特点目录数据库是以树状的层次结构来描述数据信息的。由于与关系数据库相比，目录数据库更擅长查询，且目录数据库中的数据读取和查询效率非常高，比关系型数据库还要快得多，因此目录数据库非常适合于管理网络中的资源。
2019/12/13
2019/12/13
第四章活动目录的逻辑结构和物理结构
8
网络构建与管理
4.1.1 活动目录的基本概念
“活动”说明这个目录是动态的、可以扩展的，具体体现如下：
活动目录中对象的数目是没有限制的。活动目录中对象的属性是可以增加的。可以方便地添加或删除域。
2019/12/13
第四章活动目录的逻辑结构和物理结构
2019/12/13
第四章活动目录的逻辑结构和物理结构
11
网络构建与管理

机器人机构学【ch04】串联机器人机构拓扑结构特征与综合培训教学课件

3)同一连杆上两运动副轴线平行，两者之间用“//”表示，如R//R，R//P，R//H， P//P等。
串联机器人机构拓扑结构特征
4)同一连杆上两运动副轴线相交于一点，两者共用“⌒”表示。
5)若干个P副平行于同一平面，用 (-P-P-…-P-)表示。
“
6)同一连杆上两运动副轴线垂直，两者之间用“⊥”表示。
i(扭角)：两相邻运动副轴线之间的夹角，即按右手坐标系，绕xi轴线由zi到zi+1的转角。
串联机器人机构拓扑结构特征
1)两运动副轴线重合，即 αi=0，ai=0。
2)两运动副轴线平行，即 αi=0，ai≠0。
上述机器人连杆的关节运动副可特殊配置
如下：
3)两运动副轴线相交于一点，即αi≠0，ai=0。
”
串联机器人机构拓扑结构特征
串联机器人机构的活动度公式
串联机器人机构的活动度公式为
m
F fi i1
式中，F为机构活动度；m为机构运动副数；fi为第i个运动副自由度数。
串联机器人机构拓扑结构特征
串联机器人机构运动输出特征矩阵
串联机器人机构的位移输出与速度输出
串联机器人机构的位移输出是末端连杆的位置与方向(位姿)，为机构运动输入的函数。串
串联机器人机构运动输出特征方程
4)相互平行(重合)的两个转动必相关，只对应一个独立转动输出。
5)平行于同一平面的三个转动必相关。
“ 6)不平行于同一平面的四个转动必相关，三维空间内最多有三个独立的转动输出。 ”
03
串联机器人机构运动输出特征矩阵运算
串联机器人机构运动输出特征矩阵运算运动输出特征矩阵运算规则
步骤1 选定单开链的运动输出特征矩阵MS。

中级财务会计英文ch04-文档资料

Chapter 4-7
Cash
Overdraft
Negative bank account balance reported as a current liability.
Compensating balance
Minimum balance that must be maintained in a company’s account as support for funds borrowed from the bank.
Travel Expenses Customer Business Lunches Express Mail Postage Miscellaneous Office Supplies
$79.30 93.42 55.00 32.48
Prepare the journal entry to record replenishing fund if the balance on July 31 was $137.80.
中级财务会计英文ch04-文档资料
点击此处可添加副标题
Cash and Receivables
Chapter
4
Intermediate Accounting 12th Edition
Kieso, Weygandt, and Warfield
Chapter 4-2
Prepared by Coby Harmon, University of California, Santa Barbara
balances. Permit reconciliation of ledger and bank cash
account balances. Result in the physical control of cash.

ch04-指令系统

把累加器A中的内容与源操作数所指的数
据相互交换。（5条）
– – – – – XCH A, Rn XCH A, @Ri XCH A, direct XCHD A, @Ri SWAP A
堆栈操作指令
– PUSH direct • 先将堆栈指针SP的内容加1, 然后将direct 所指字节单元的内容送入SP所指内部RAM 单元;
40
逻辑与指令
用法（格式）：ANL Dest , Source
– ANL A, Rn
– – – – – ANL ANL ANL ANL ANL A, direct A, @Ri A, ＃data direct, A direct, ＃data
A
B
Y
0
0 1
0
1 0
0
0 0
功能：Dest Dest & Source。
程序存储器数据传送指令
（1）指令格式 – 格式：MOVC A，[源字节] – MOVC A, @A+DPTR – MOVC A, @A+PC （2）操作数：目的操作数只能是累加器
A，源操作数则采用变址寻址方式。寄存器间接地址只能是 @A+DPTR 和 @A+PC 。
数据交换类指令
内部RAM之间的数据传送指令
共5条： – MOV direct1, direct2 – MOV direct , Rn – MOV Rn , direct – MOV direct ,@Ri – MOV @Ri ,direct
与累加器A有关的数据传送指令
共6条： – MOV A，Rn – MOV Rn ， A – MOV A，direct – MOV direct ， A – MOV A，@Ri – MOV @Ri ， A

Ch04 一阶过程和二阶过程的动态特性

峰值时间最大超调nput Signals
Ramp function
xi
a
a=1 称为单位斜坡函数
0
1
t
Sinusoidal function
§4-1 Typical Input Signals
究竟采用哪种典型信号？
取决于系统在正常工况下最常见的输入信号形式斜坡信号阶跃信号脉冲信号正弦信号随时间逐渐变化的输入突然的扰动量、突变的输入冲击输入随时间往复变化的输入
1 0
5
wnt
10
15
阻尼系数、特征根与二阶系统单位阶跃响应
阻尼系数特征根
[s]
二阶系统单位阶跃响应
[s]
[s]
阻尼系数、特征根与二阶系统单位阶跃响应
阻尼系数特征根
[s]
二阶系统单位阶跃响应
[s]
[s]
§5-4 Time-domain Performance Specifications
时域分析性能指标是以系统对单位阶跃输入的瞬态响应形式给出的。

§4-3 Transient Response of Second-order Systems
二阶系统：
能够用二阶微分方程描述的系统。它的典型形式是二阶振荡环节。
形式一：
形式二：
二阶系统的单位阶跃响应
单位阶跃输入
则：
根据二阶系统的极点分布特点，分五种情况进行讨论。
欠阻尼临界阻尼过阻尼零阻尼负阻尼
t
瞬态响应
稳态响应

——动态性能描述
——稳态性能描述
标准过程输入一阶系统的瞬态响应二阶系统的瞬态响应

离散数学ch04图论根树(课件)

04
根树的性质与算法
根树的性质
根树的定义
根树的性质1
根树的性质2
根树的性质3
根树是一种有向无环图，其中有一个节点被指定为根节点，其他节点按层次结构排列，从根节点出发，每个节点恰好有一条有向边指向其子节点。
根树的节点数等于其子树的节点数之和加一。
根树的深度等于其最深叶子节点的深度加一。
路径与回路
总结词
路径与回路是图论中重要的概念，路径是指一系列连续的边和顶点，回路是指起点和终点相同的路径。
详细描述
在图论中，路径是指从起始顶点到终止顶点的一系列连续的边和顶点。每个顶点和边在路径中只出现一次，且顺序必须一致。回路则是指起点和终点相同的路径，即路径中存在一个顶点，通过一系列的边回到该顶点。回路在图论中具有重要意义，如在欧拉路径。
图论的重要性
图论在计算机科学、电子工程、交通运输、生物信息学等领域有
广泛应用。
图论为复杂系统提供了统一的数学框架，使得可以运用数学方法和计算机技术来分析和优化这些
系统。
图论在解决实际问题中发挥了关键作用，如路由优化、社交网络分析、蛋白质相互作用网络等。
算法效率和复杂性的优化
在解决实际问题时，算法的效率和复杂性是关键因素。如何优化图论和根树的算法，提高其计算效率和降低其计算复杂性，是一个具有挑战性的问题。
THANKS
感谢观看
低运输成本。
交通控制
03
根树可以用于构建交通信号灯的控制逻辑，提高道路的通行效
率。
06
总结与展望
图论与根树的重要性和发展前景
重要应用领域
图论和根树在计算机科学、电子工程、交通运输、生物信息学等领域有广泛的应用，对解决实际问题具有重要意义。

ch04弹性理论

弹性公式

弧弹性公式
ΔQ/（Qa+Qb）/2 ΔQ Pa+Pb Ed = -———————— 或 =- — × —— ΔP/（Pa+Pb）/2 ΔP Qa+Qb

点弹性公式与计算
dQ/Q dQ P Ed =- —— 或 = -—×— dP/P dP Q
弹性计算

某杂志价格为2元时销售量为5万册，价格为3元时销售量为3万册，则需求价格弹性为多少？
以大幅度减少，税收就主要由生产者承当。

对食盐、香烟、汽油征税和娱乐产业征税的不同效果
练习回复

在竞争性商品X市场中，有10000个相同的个人，每个人的需求函数都是 Qd＝12 －2P，同时又有1000个相同的生产者，每个生产者的供给函数都是Qs＝20P. 1）求商品X的市场需求函数和市场供给函数。 2）在同一坐标系中，绘出商品X 的市场需求曲线和市场供给曲线，并表示出均衡点。 3）求均衡价格和均衡产销量。
影响需求价格弹性的因素

商品的可替代性商品用途的广泛性

商品对消费者的重要程度
商品的消费支出在消费总支出中所占的比重
消费者调节需求量的时间。
需求收入弹性

定义：需求收入弹性是指某种商品需求量变动的百分比与收入变动的百分比之比。

公式：ΔQ/Q
ΔY/Y
ΔQ Y
ΔY Q
Ey = —— 或 = —× —
解：P=1，则Qs = c+d，另dQ/dP= d dQ P 1 d Es = —×— = d × —— = —— dP Q c+d c+d
分类及影响因素

①Es=0，供给完全无弹性 ②0<Es<1，供给缺乏弹性

ch04-1(补充)逻辑符号的等效变换

A B & C ≥1 L A B & C ≥1 L
3．一端消去或加上小圆圈，同时将相应变量取反，其逻辑关系不变。
A B & L B A & L B A & L
三、逻辑门等效符号的应用
利用逻辑门等效符号，可实现对逻辑电路进行变换，以简化电路，能减少实现电路的门的种类。
A
A B A B & & ≥1 L
A B
A B
≥1
L A B AB
L A B AB
A B ≥1 L = A+ B A B &
L AB A B
二. 逻辑小圆圈，其逻辑关系不变。
C A B & ≥1 L A B & C ≥1 L
2．任一条线一端上的小圆圈移到另一端，其逻辑关系不变。
4-1(补充) 基本逻辑门电路的等效符号及其应用一、基本逻辑门电路的等效符号
L AB A B
L AB
A B
&
L AB
A B
≥1
与非门及其等效符号
L A B AB
或非门及其等效符号
L A B
A B
≥1
A B
&
L AB
L AB A B
& L = AB
& ≥1 & L
B A B
A B A B
& & & L
P Q
&
L P Q

ch04-1水分及水分活度的测定

第1节概述
四、水分含量测定的重要性 (二)水分含量测定的重要性水分含量在产品保藏中是一个关键的质量因素,可以直接影响一些产品质量的稳定性。如： ①脱水蔬菜和水果； ②奶粉； ③鸡蛋粉水分含量是产品的一个质量因素。如： ①在果酱和果冻中,防止糖结晶； ②常规加工过的谷物,水分含量为4%~8%；吸潮中的水
第1节概述
一、水的作用 ①水是生物体的重要组成部分,是维持动、植物和人类生存必不可少的物质之一。除谷物和豆类等的种子类食品（一般水分在12~16%）以外,作
为食品的许多动植物一般含有60~90%水分,有的甚至更高,水是许多食品组戊戊分中数量最多的组分。如蔬菜含水分85~97%、水果80~90%、鱼类 67~81%、蛋类73~75%、乳类87~89%、猪肉43~59%,即使是干态食品,也含有少量水分,如面粉12~14%、饼干2.5~4.5%。 ②在动、植物体内,水分不仅以纯水状态存在,而且常常是溶解那些可溶
滞化水
毛细管水
自由流水
第1节概述
三、水分在食品中的存在形式 (一)体相水 2.截留水 Entrapped water that occupies positions furthest removed from
nonaqueous constituents; water-water hydrogen bonds predominate; has properties similar to water in a dilute salt solution, except macroscopic flow is impeded by matrix of gel or tissue. 能结冰,但冰点有所下降；溶解溶质的能力强,干燥时易被除去,冷冻时易结冰；与纯水分子平均运动接近；适合微生物生长和大多数的化学反应 ,易引起食品的腐败变质,但与食品的风味和功能性紧密相关。如：当组织状食品被切割或跺碎时水分不会流出,这部分水的整体流动收到严格限制,但各个分子分子运动基本与在稀盐溶液中的水分子运动相同。截留水的损害对食品质量会有很大影响：凝胶脱水收缩、冷冻食品的解冻渗出等

ch04国际经济学课后答案与习题（萨尔瓦多）

ch04国际经济学课后答案与习题（萨尔⽡多）*CHAPTER 4(Core Chapter)THE HECKSCHER-OHLIN AND OTHER TRADE THEORIESOUTLINE4.1 Introduction4.2 Factor Endowments and the Heckscher-Ohlin Theory4.3 The Formal Heckscher-Ohlin ModelCase Study 4-1 The Revealed Comparative Advantage of Various Countries and Regions4.4 Factor-Price Equalization and Income DistributionCase Study 4-2 Has International Trade Increased U.S. Wage Inequalities?4.5 Empirical Tests of the Heckscher-Ohlin Theory4.6 Economies of Scale and International TradeCase Study 4-3 The New International Economies of Scale4.7 Trade Based on Product DifferentiationCase Study 4-4 Growth of Intra-Industry Trade4.8 Technological Gap and Product Cycle ModelsCase Study 4-5: The United States as the Most Competitive Economy in the World4.9 Transportation Costs and International Trade4.10 Environmental Standards and International TradeAppendix The Specific-Factors Model and Intra-Industry Trade ModelsA4.1 The Specific-Factors ModelA4.2 A Model of Intra-Industry TradeKey TermsInternationalofscaleeconomies pricesRelativefactorproducts Heckscher–Ohlin (H–O) theory DifferentiatedtradeIntra-industryHeckscher–Ohlintheorem(H–O)Factor-proportions or factor-endowment theory Technological gap modelcyclemodelProductFactor–price equalization theoremcostsTransportationStolper-Samuelsontheoremmodel Nontraded goods and services Specific-factorsparadox Environmental standardsLeontiefMonopolisticcompetitionscalereturnsIncreasingtoLecture Guide1. This is one of the most important and difficult chapters in the book. It is also a long chapter andrequires four lectures to cover adequately.2. In the first lecture, I would cover sections 1-3. Section 3 is one of the most important sections inthe book because it presents the H-O model. I would proceed slowly and carefully in explaining Figure 4.1 and compare it to the standard trade model of Figure 3.4.3. In the second lecture, I would cover sections 4 and 5. Section 4 on the factor-price equalizationtheorem and income distribution is a difficult section. Case Study 4-2 should be of great interest to the students and give rise to a great deal of class discussion.4. In third lecture, I would cover sections sections 6-7, paying a great deal of attention to section 7on trade in differentiated products.5. In fourth lecture, I would cover the rest of the chapter.Answers to Review Questions and Problems1. a. The Heckscher–Ohlin (H-0) theorem postulates that a nation will export those commodi- ties whose production requires the intensive use of the nation’s relatively abundant and cheap factor and import the commodities whose production requires the intensive useof the nation’s relatively scarce and expensive factor. In short, the relatively labor-richnation exports relatively labor-intensive commodities and imports the relativelycapital-intensive commodities.b. Heckscher and Ohlin identify the relative difference in factor endowments amongnations as the basic determinant of comparative advantage and international trade.c. The H-O Theory represent an extension of the standard trade model because it explains the basis for comparative advantage (classical economists, such as Ricardo had assumed it) and examines the effect of international trade on factor prices and income distribution (which classical economists had left unanswered).2. See Figure 1 on the next page.3. a. The factor–price equalization theorem postulates that international trade will bring about the equalization of the returns to homogeneous or identical factors across nations.b. The Stopler-Samuelson theorem postulates that free international trade reduces the realincome of the nation’s relatively scarce factor and increases the real income of the nation’s relatively abundant factor.Fig 4.1Fig 4.2XXb. The specific-factors model postulates that the opening of trade (1) benefits the specific factorused in the production of the nation’s export commodity, (2) harms the specific factor used in the production of the nation’s import-competing industry, and (3) leads to an ambiguouseffect (i.e., it may benefit or harm) the mobile factor.c. Trade acts as a substitute for the international mobility of factors of production in itseffect on factor prices. With perfect mobility, labor would migrate from the low-wagenation to the high-wage nation until wages in the two nations are equalized. Similarly,capital would move from the low-interest to the high-interest nation until the rate ofinterest was equalized in the two nations.4. a. The Leontief paradox refers to the original Leontief’s finding that U.S. import substituteswere more K-intensive than U.S. exports. This was the opposite of what the H-O theorempostulated.b. The Leontief paradox was resolved by including human capital into the calculations andexcluding industries based on natural resources. Recent research using data on many sectors, for many countries, over many years, and considering that countries could specialize in aparticular subset or group of commodities that were best suited to their specific factorendowments, provides strong support for the H-O theorem.c. The Hecksher-Olhin theory remains the centerpiece of modern trade theory for explaininginternational trade today. To be sure, there are other forces (such as economies of scale,product differentiation, and technological differences across countries) that provide additional reasons and explanations for some international trade not explained by the basic H-O model.These other trade theories complement the basic H-O model in explaining the pattern ofinternational trade in the world today.5. International trade with developing economies, especially newly industrializing economies (NIEs), contributed in two ways to increased wage inequalities between skilled and unskilled workers in the United States during the past two decades. Directly, by reducing the demand for unskilledworkers as a result of increased U.S. imports of labor-intensive manufactures and, indirectly, byspeeding up the introduction of labor-saving innovations, which further reduced the U.S.demand for unskilled workers. International trade, however, was only a small cause of increased wage inequalities in the United States. The most important cause was technological change.6. a. Economies of scale refer to the production situation where output grows proportionatelymore than the increase in inputs or factors of production. For example, output may morethan double with a doubling of inputs.b. Even if two nations were identical in every respect, there is still a basis for mutually bene-ficial trade based on economies of scale. When each nation specializes in the production of one commodity, the combined total world output of both commodities will be greater thanthan without specialization when economies of scale are present. With trade, each nationthen shares in these gains.c. The new international economies of scale refers to the increase in productivity resultingfrom firms purchasing parts and components from nations where they are made cheaperand better, and by establishing production facilities abroad-26-7. a. Product differentiation refers to products that are similar, but not identical. Intra-industrytrade refers to trade in differentiated products, as opposed to inter-industry trade incompletely different products.b. Intra-industry trade arises in order to take advantage of important economies of scale inproduction. That is, with intra-industry trade each firm or plant in industrial countries canspecialize in the production of only one, or at most a few, varieties and styles of the sameproduct rather than many different varieties and styles of a product and achieve economies of scale.c. With few varieties and styles, more specialized and faster machinery can be developedfor a continuous operation and a longer production run. The nation then imports othervarieties and styles from other nations. Intra-industry trade benefits consumers because ofthe wider range of choices (i.e., the greater variety of differentiated products) available atthe lower prices made possible by economies of scale in production.8. a. According to the technological gap model, a firm exports a new product until imitators incountries take away its market. In the meantime, the innovating firm will have introduced a new product or process. b. The criticism of the technological gap model are that it does not explain the size of techno- logical gaps and does not explore the reason for technological gaps arising in the first place, or exactly how they are eliminated over time.c. The five stages of the product cycle model are: the introduction of the product, expansion of production for export, standardization and beginning of production abroad through imitation, foreign imitators underselling the nation in third markets, and foreigners underselling theinnovating firms in their home market as well.9. See Figure 2 on page 25.10. A nation with lower environmental standards can use the environment as a resource endow-ment or as a factor of production in attracting polluting firms from abroad and achieving acomparative advantage in the production of polluting goods and services. This can lead totrade disputes with nations with more stringent environmental standards.-27-Multiple-Choice Questions1. The H-O model extends the classical trade model by:a. explaining the basis for comparative advantageb. examining the effect of trade on factor prices*c. both a and bd. neither a nor b2. A nation is said to have a relative abundance of K if it has a:a. greater absolute amount of Kb. smaller absolute amount of Lc. higher L/K ratio*d. lower price of K in relation to the price of L3. A difference in relative commodity prices between nations can be based on a difference in:a. technologyb. factor endowmentsc. tastes*d. all of the above4. In the H-O model, international trade is based mostly on a difference in:a. technology*b. factor endowmentsc. economies of scaled. tastes5. According to the H-O theory, trade reduces international differences in:a. commodity pricesb. in factor prices*c. both commodity and factor pricesd. neither relative nor absolute factor prices6. According to the Stolper-Samuelson theorem, international trade leads toa. reduction in the real income of the nation’s relatively abundant factor*b. reduction in the real income of the nation’s relatively scarce factorc. increase in the real income of the nation’s relatively scarce factord. none of the above7. Which of the following is false with regard to the specific factors theorem, international trade *a. harms the immobile factors that are specific to the nation’s export commodities or sectorsb. harms the immobile factors that are specific to the nation’s import-competing commoditiesc. has an ambiguous effect on the nation’s mobile factorsd. may benefit or harm the nation’s mobile factors8. Perfect international mobility of factors of productiona. leads to a reduction in international differences in the returns to homogenous factorsb. acts as a substitute for international trade in its effects on factor pricesc. operates on the supply of factors in affecting factor prices*d. all of the above9. The Leontief paradox refers to the empirical finding that U.S.*a. import substitutes were more K-intensive than exportsb. exports were more L-intensive than importsc. exports were more K-intensive than import substitutesd. all of the above10. From empirical studies, we conclude that the H-O theory:a. must be rejectedb. must be accepted without reservations*c. can generally be acceptedd. explains all international trade11. International trade can be based on economies of scale even if both nations have identical:a. factor endowmentsb. tastesc. technology*d. all of the above12. A great deal of international trade:a. is intra-industry tradeb. involves differentiated productsc. is based on monopolistic competition*d. all of the above13. Intra-industry trade takes place:a. because products are homogeneous*b. in order to take advantage of economies of scalec. because perfect competition is the prevalent form of market organizationd. all of the above14. Which of the following statements is true with regard to the product-cycle theory?a. it depends on differences in technological changes over time among countriesb. it depends on the opening and the closing of technological gaps among countriesc. it postulates that industrial countries export more advanced products to lessadvanced countries*d. all of the above15. Transport costs:a. increase the price in the importing countryb. reduces the price in the exporting countryc. falls less heavily on the nation with the more elastic demand and supply curves of the traded commodity*d. all of the above-30-ADDITIONAL ESSAYS AND PROBLEMS FOR PART ONE1. Assume that both the United States and Germany produce beef and computer chips with the following costs: United States Germany(dollars) (marks)Unit cost of beef (B) 2 8Unit cost of computer chips (C) 1 2(a) What is the opportunity cost of beef (B) and computer chips (C) in each country?(b) In which commodity does the United States have a comparative cost advantage?What about Germany?(c) What is the range for mutually beneficial trade between the United States and Germanyfor each computer chip traded?(b) How much would the United States and Germany gain if 1 unit of beef is exchangedfor 3 chips?Answ. (a) In the United States:the opportunity cost of one unit of beef is 2 chips;the opportunity cost of one chip is 1/2 unit of beef.In Germany:the opportunity cost of one unit of beef is 4 chips;the opportunity cost of one chip is 1/4 unit of beef.(b) The United States has a comparative cost advantage in beef with respect to Germany,while Germany has a comparative cost advantage in computer chips.(c) The range for mutually beneficial trade between the United States and Germany foreach unit of beef that the United States exports is2C < 1B < 4C(d) Both the United States and Germany would gain 1 chip for each unit of beef traded.2. Given: (1) two nations (1 and 2) which have the same technology but different factor costs conditions, and (3) no transportation costs, tariffs, or other obstructions to trade.Prove geometrically that mutually advantageous trade between the two nations is possible.Note: Your answer should show the autarky (no-trade) and free-trade points of production and consumption for each nation, the gains from trade of each nation, and express the equilibrium condition that should prevail when trade stops expanding.) Ans.: See the figure below.Fig 4.3Fig 4.4Nations 1 and 2 have different production possibilities curves and different community indifference maps. With these, they will usually end up with different relative commodity prices in autarky, thus making mutually beneficial trade possible.In the figure, Nation 1 produces and consumes at point A and Px/Py=P A in autarky, while Nation 2 produces and consumes at point A' and Px/Py=P A'. Since P A < P A', Nation 1 has a comparative advantage in X and Nation 2 in Y. Specialization in production proceeds until point B in Nation 1 and point B' in Nation 2, at which P B =P B' and the quantity supplied for export of each commodity exactly equals the quantity demanded for import.Thus, Nation 1 starts at point A in production and consumption in autarky, moves to point B in production, and by exchanging BC of X for CE of Y reaches point E in consumption. E > A since it involves more of both X and Y and lies on a higher community indifference curve.Nation 2 starts at A' in production and consumption in autarky, moves to point B' in production, and by exchanging B'C' of Y for C'E' of X reaches point E'in consumption (which exceeds A').At Px/Py=P B =P B', Nation 1 wants to export BC of X for CE of Y, while Nation 2 wants to export B'C' (=CE) of Y for C'E' (=BC) of X. Thus, P B =P B' is the equilibrium relative commodity price because it clears both (the X and Y) markets.3. (a) Identify the conditions that may give rise to trade between two nations. (b) What aresome of the assumptions on which the Heckscher-Ohlin theory is based? (c) What does this theory say about the pattern of trade and effect of trade on factor prices?Ans. (a) Trade can be based on a difference in factor endowments, technology, or tastesbetween two nations. A difference either in factor endowments or technology results in a different production possibilities frontier for each nation, which, unlessneutralized by a difference in tastes, leads to a difference in relative commodity price and mutually beneficial trade. If two nations face increasing costs and have identical production possibilities frontiers but different tastes, there will also be a differencein relative commodity prices and the basis for mutually beneficial trade between the two nations. The difference in relative commodity prices is then translated into adifference in absolute commodity prices between the two nations, which is the immediate cause of trade.(b) The Heckscher-Ohlin theory (sometimes referred to as the modern theory – asopposed to the classical theory - of international trade) assumes that nations have the same tastes, use the same technology, face constant returns to scale (i.e., a givenpercentage increase in all inputs increases output by the same percentage) but differ widely in factor endowments. It also says that in the face of identical tastes or demand conditions, this difference in factor endowments will result in a difference in relative factor prices between nations, which in turn leads to a difference in relativecommodity prices and trade. Thus, in the Heckscher-Ohlin theory, the internationaldifference in supply conditions alone determines the pattern of trade. To be noted is that the two nations need not be identical in other respects in order for internationaltrade to be based primarily on the difference in their factor endowments.(c) The Heckscher-Ohlin theorem postulates that each nation will export the commodityintensive in its relatively abundant and cheap factor and import the commodityintensive in its relatively scarce and expensive factor. As an important corollary, itadds that under highly restrictive assumptions, trade will completely eliminate thepretrade relative and absolute differences in the price of homogeneous factors amongnations. Under less restrictive and more usual conditions, however, trade will reduce, but not eliminate, the pretrade differences in relative and absolute factor prices among nations. In any event, the Heckscher-Ohlin theory does say something very useful onhow trade affects factor prices and the distribution of income in each nation. Classical economists were practically silent on this point.4. Suppose that tastes change in Nation 1 (the L-abundant and L-cheap nation) so that consumers demand more of commodity X (the L-intensive commodity) and less of commodity Y (the K- intensive commodity). Suppose that Nation 1 is India, commodity X is textiles, and commodi- ty Y is food. Starting from the no-trade equilibrium position and using the Heckscher-Ohlinmodel, trace the effect of this change in tastes on India's (a) relative commodity prices anddemand for food and textiles, (b) production of both commodities and factor prices, and(c) comparative advantage and volume of trade. (d) Do you expect international trade to leadto the complete equalization of relative commodity and factor prices between India and theUnited States? Why?Ans. (a) The change in tastes can be visualized by a shift toward the textile axis in India'sindifference map in such a way that an indifference curve is tangent to the steepersegment of India's production frontier (because of increasing opportunity costs) after the increase in demand for textiles. This will cause the pretrade relative commodity price of textiles to rise in India.(b) The increase in the relative price of textiles will lead domestic producers in India toshift labor and capital from the production of food to the production of textiles. Since textiles are L-intensive in relation to food, the demand for labor and therefore the wage rate will rise in India. At the same time, as the demand for food falls, thedemand for and thus the price of capital will fall. With labor becoming relative more expensive, producers in India will substitute capital for labor in the production of both textiles and food.(c) Even with the rise in relative wages and in the relative price of textiles, India stillremains the L-abundant and low-wage nation with respect to a nation such as theUnited States. However, the pretrade difference in the relative price of textilesbetween India and the United States is now somewhat smaller than before the change in tastes in India. As a result the volume of trade required to equalize relativecommodity prices and hence factor prices is smaller than before. That is, India need now export a smaller quantity of textiles and import less food than before for therelative price of textiles in India and the United States to be equalized. Similarly, the gap between real wages and between India and the United States is now smaller and can be more quickly and easily closed (i.e., with a smaller volume of trade).(d) Since many of the assumptions required for the complete equalization of relativecommodity and factor prices do not hold in the real world, great differences can be expected and do in fact remain between real wages in India and the United States.Nevertheless, trade would tend to reduce these differences, and the H-O model does identify the forces that must be considered to analyze the effect of trade on thedifferences in the relative and absolute commodity and factor prices between Indiaand the United States.5. (a) Explain why the Heckscher-Ohlin trade model needs to be extended. (b) Indicate in what important ways the Heckscher-Ohlin trade model can be extended. (c) Explain what ismeant by differentiated products and intra-industry trade.Ans. (a) The Heckscher-Ohlin trade model needs to be extended because, while generallycorrect, it fails to explain a significant portion of international trade, particularly the trade in manufactured products among industrial nations.(b) The international trade left unexplained by the basic Heckscher-Ohlin trade model canbe explained by (1) economies of scale, (2) intra-industry trade, and (3) trade based on imitation gaps and product differentiation.(c) Differentiated products refer to similar, but not identical, products (such as cars,typewriters, cigarettes, soaps, and so on) produced by the same industry or broadproduct group. Intra-industry trade refers to the international trade in differentiated products.。

机械制造基础ch04机床基本知识

5 . 按机床主要工作部件的数目可分为：
单轴（single axle）多轴（multi spindle）单刀（single-tool）多刀机床（multi-cutter machine tool）
机床数控化引起机床传统分类方法发生变化，主要表现在机床品种不是越分越细，而应是趋向综合。
二、机床型号编制方法: （regimentation method of machine tool’s model number）
其中：
1）有（）的代号或数字，当无内容时则不表示，若有内容则不带括号；
2）有○符号者，为大写的汉语拼音字母；
3）有△符号者，为阿拉伯数字；
4）有 ○△ 符号者，为大写的汉语拼音字母或者为阿
拉伯数字、或两者兼有之。
通用机床型号辅助部分:
基本部分/ （ Δ ）（- Δ ）
其它特性代号企业代号
例1： CA6140型卧式车床
2、
联系复合运动之内的各个分解部分，因而传动链所联系的执行件相互之间的相对速度（相对位移量）有严格的要求，以保证运动的轨迹。
在内联系传动链中，不应有摩擦传动或是瞬时传动比变化的传动件（如链传动）。
注：
有几个简单运动就有几个外联系传动链，它们可以有各自的运动源，也可共用一个运动源。内联系传动链本身不能提供运动，需要有外联系传动链将运动源传到内联系传动链上来。如果外联系传动链与内联系传动链有公用段，内、外传动链的换置器官（机构）不应布置在公共段。
三、传动原理图
定比机构：传动比固定的传动机构。换置机构：变换传动比的传动机构。
用一些简明的符号把传动原理和传动路线表示出来，就是传动原理图。
例：卧式车床的传动原理图

张量分析与弹性力学：ch04-exercises

其中 k, a, b 是远小于 1 的常数。
张
(武汉大学)
张量分析与
学
2016 年 4 月 6 日 2 / 4
1 习题
张
(武汉大学)
张量分析与
学
2016 年 4 月 6 日 3 / 4
习题 1
x2 1 (1)
(1, 1)
O (a)
x2 1 (2)
x1 1
(1, 1)
x1
O
1
(a)
张
(武汉大学)
x2 1.2
+ e2)
上线元的变Байду номын сангаас长度比与
变形后的新方向。
张量分析与
学
2016 年 4 月 6 日 3 / 4
习题 2
在图示的四面体 OABC 中，已
知 OA = OB = OC，D 是 AB 的中点。设柯西应变张量为
0.010
(εij) = −0.005
.
−0.005 0.020 0.010
. 0.010
所发布文档来源于互联网和个人收集仅用于分享交流使用版权为原作者所有
第四章应变分析
习题
武汉大学测绘学院张
2016 年 4 月 6 日
张
(武汉大学)
张量分析与
学
2016 年 4 月 6 日 1 / 4
习题
试分析以下应变状态是否存在。 1 εx = k(x2 + y2)z, εy = ky2z, εz = 0; γxy = 2kxyz, γyz = γzx = 0； 2 εx = k(x2 + y2), εy = ky2, εz = 0; γ = 2kxy, γyz = γzx = 0； 3 εx = axy2, εy = ax2y, εz = axy; γxy = 0, γyz = az2 + by2, γxz = ax2 + by2。

(完整版)ch04_-_the_electronic_structure_of_atoms

11
New Way Chemistry for Hong Kong A-Level Book 1
4.1 The Electromagnetic Spectrum (SB p.96)
How can we know the energy levels are getting closer and closer together?
Niels Bohr
Bohr’s Model of H atom
3
New Way Chemistry for Hong Kong A-Level Book 1
4.1 The Electromagnetic Spectrum (SB p.91)
The Electromagnetic Spectrum
bright lines
c
c
4
New Way Chemistry for Hong Kong A-Level Book 1
4.1 The Electromagnetic Spectrum (SB p.92)
Continuous spectrum of white light
Fig.4-5(a)
5
New Way Chemistry for Hong Kong A-Level Book 1
8
New Way Chemistry for Hong Kong A-Level Book 1
4.1 The Electromagnetic Spectrum (SB p.94)
Interpretation of the Atomic Hydrogen Spectrum
9
New Way Chemistry for Hong Kong A-Level Book 1

ch04-1电力系统故障分析及计算

Uq Eq jxd Id
Ud jxq Iq
U Ud Uq Eq jxq Iq jxd Id U Eq j(xq xd )Iq jxd I
id’
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+
uq
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1、暂态电抗和暂态电势
id )
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f xadid x f i f xad (i f id ) xf i f
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无阻尼绕组Park方程的等值电路
25
戴维南定理 id’
Eq’
xd’
+
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+
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1、暂态电抗和暂态电势
从 d , f 方程中消去 i f ，得
)
ic
X
R' X' R' X'
i ip ia 强制分量自由分量
ip
Im
sin(t
)
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sin(t
)
ia Ce pt C exp( t / Ta )
Ta
L R
Z R2 X 2
arctg X
R
8
i (0)
i(0_)
Im(0) sin( (0) )
Im(0) sin( (0) ) Im sin( ) C
△ifa
△if
定转子子各各绕绕组组磁磁链量变保化持为初零始值定子转三子相绕绕组组磁的链磁变链化保持为21初零值
（三）忽略阻尼绕组同步电机突然三相短路的物理分析

长虹CPU对照及代换--厂方资料

长虹系列彩电微处理与机型对照表—厂方资料（F04）PF2163（F04）PF2163PF216522CH05T1611TDA9373PS-N223CH05T1621OM8373PS CH-16DPF3495PF2995PF2595PF25156PF25118PF2588（F6）SF2588（F6）SF2583（F05）SF2598（F06）SF2539（F05）SF2511（F06）PF29008PF29118PF2985（F06）PF2983（F05）SF2911（FB0）SF2911F （FB0）PF2992（FB0）PF2939（F05）SF3488（F06）SF3411（FB0）SF3411F （FB0）24CHT0606MN1873287CN-1125E1828E18PF209E25CHT0807TMP87CM38N-3529CN-9R2112T R2113T R2115T BT R2116BT R2117T BT R2118T BT 14B2721B33PF21B826CHT0808TMP87CM38N-3593CH-1029D8327CHT0818TMP87CM38N-1A22CH-1029SD8329D85R2518AE （D ）2625FD29D83D298328CHT0819TMP87CM38N-3673CN-9G2510（B ）G2521G2526G2526（B ）G2929G253929CH0827TMP87CM38N CN-9G2923D29D3B C2985B C2929B G2125PF21B8PF29B830CH08T0601TMPA8803CN-18A SF2168E SF2170E SF1498E31CH08T060432CH08T0609TMPA8823CN-18EAPF2193E PF2118E PF2191E SF2193E SF2118E SF2191E PF2193E （F18）SF2191E （F08）SF1498E （A ）SF2191E（G ）33CH08T060234CH08T0608PF2591E SF2991E SF2918E PF2518E SF2591E SF2991EF SF3418EF SF2918EF SF2518E SF2991E HD25933HD29933PF2918E PF3418E PF2991E PF2918E （N ）PF3418E （N ）SF2591EGPF2593E PF2518E （N ）PF29S1835CH08T0607PF2955E HD29966SF2566E SF2966ESF3466E H29D80E H34D80E 36CH08T0610TMPA8829CN-18EDPF2993E PF3493E HD29988HD3498837TMP87CP38NCN-6G2966A B C G2967A G3898R2916C2917G 2918G 2919G R3818G 38TMP87CM38N CN-7T2981/A/C T2982/A CT3418/A C3419T/PT R2916T/17T/18T/19TR3415T/16T 39CHT1201S3C8837D37G2573G2585G2983G2983A PF29D9PF29D1840CHT1202S3C8837D3741KS88P8324NCH-10DG298525D85PF29D934D88G2988G2585G29D9G29D66G3478G3480G3488G298D PF299D H34D80H3489DH29D80H2919D G299D G29D9（A）PF2519D H29S86（D）PF29D9（A）42CH12T1004S3C8849X24CH-10D PF3489D G3578H2519D PF29D18（A）PF2989D PF2589D H2589D PF348DH34D80H29S96D43CH78T0601P87C766DT-6DP2998（01）DP3488DP3498长虹新机型微处理器的带换一.CN-12机心微处理器的带换1.CH0406-5M18为最早状态，100套节目豫置，存储器为24C04；2.CH0410-5P78可以带换CH0406-5M18，但存储器需更换为24C08，重新进行ROM校正；3.CHT0416-5V58可以直接带换CH0410-5P78，CHT0416-5V58本身无需ROM校正；4.CHT0416-52D9与CHT0416-5V58，可以直接带换；5.CH04T1218-5W60可以直接带换CHT0416-5V58、CHT0416-52D9、CHT0410-5P78、CH0406-5M18，但总线数据需做调整；其它CPU不允许带换CH04T1218-5W60；6.CH0410-5P78也可以替换CHT0416-5V58、CHT0416-52D9，由于存储器需进行ROM校正一般情况下不推荐；7.CH04T1229-51V9与以上CPU管脚兼容，但遥控器不同（CH04T1229-51V9为长虹统一编码），不允许互换；特殊情况下，若的确相互换，需将遥控器、存储器一并更换，同时需正得用户同意，因为相互带换后，屏幕显示内容完全发生了变化。

CH-04-1电弧理论

电气运行
1.吹弧
电气运行
2.采用多断口灭弧
电气运行
3.短电弧灭弧
这种灭弧方法是近阴极效应的利用。当触点间发生电弧后，由于磁场的作用，把电弧吸引到栅片内，将长弧分割成一串短电弧。电弧过零时，每个短电弧的阴极附近立即出现 150 一 250V 的介质电强度。如果触点间的电压小于各个间隙介质电强度的总和，电弧将会熄灭。这种灭弧方法在低压开关电器中效果显著。
电气运行
弧隙介质强度的恢复过程是指在电弧电流过零时电弧熄灭，而弧隙的绝缘能力要经过一定时间恢复到绝缘的正常状态的过程。影响弧隙介质恢复的因素，除了介质的种类、状态、电极材料、形状等外，还有近阴极效应。
电气运行
近阴极效应：
但电流过零极性改变是，弧隙中剩余带电粒子的运动方向也随之改变，由于电子的质量比正离子小得多，弧隙极性改变时，电子能迅速地向相反方向运动，而正离子却几乎不动，这样，在新阴极附近形成了只有正离子的离子空间。其电导很低，显示出一定的介质电强度，约在0.1~1微秒的短暂时间内有150~250V的起始介质电强度。这种现象有利于电弧的熄灭。随后，弧隙介质电强度恢复的快慢，主要取决于冷却条件。
电气运行
开关电器
开关电器是用来接通或切断电路的电气设备。发电厂、变电站中的设备的投入或退出、系统运行方式的改变都必须用开关电器进行。
开关电器主要是指断路器、隔离开关、熔断器、负荷开关、闸刀开关、接触器、起动器等电气设备。
电气运行
开关电器分类
根据开关电器在电路中担负的任务，可分为：（1）仅用来正常工作情况下，断开或闭合工作电流。如高压负荷开关、低压闸刀开关、接触器、磁力启动器。（2）仅用来断开故障情况下的过负荷电流或短路电流。若高、低压熔断器。（3）既用来断开或闭合工作电流，也用来断开或闭合过负荷电流或短路电流。如高压断路器、低压自动空气断路器等。（4）不要求断开或闭合工作电流，但具备一定的切、合电容电流和环流的能力，在检修时则用来隔离电压。如隔离开关等。

《传感器与检测技术》胡向东ch04-1

f 20kHz T 30 C
15
例：差动式电感测厚仪
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电感式接近传感器
一、工作原理
两种状态：振荡、停振
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二、特性及工作方式
1、检测距离与被测体尺寸的关系
1 2
3 4
1
L
S
L > 30mm，S 与 L 无关。检测距离 S 因金属材料的不同而不同。
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2、检测距离与被测体厚度的关系铝材料：被测体厚度 > 1mm 时，检测距离稳定。
3、机械手的限位
23
4、生产工件加工定位
5、时序控制
24
股道占用智能判别系统
1、股道占用
2、股道占用已有判别方法及不足：轨道电路
3、股道占用智能判别系统
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电感接近开关的涡流工作原理？根据差动式电感测厚仪的原理，说明如何判定铁心移动方向？用电感接近传感器设计股道占用智能判别系统。（1）系统组成、工作原理及过程。（2）传感器选型：型号、主要技术参数（动作距离：20mm）（3）传感器在轨道上的安装方式。（4）如何判断行进方向？
0 AW 2 2 0 1 2 0 2( 0 ) L0 0 L1 1 ( ) L 0 0 1 0 0
L
0

3
L1 当 1时， ...... L0 0 0 0 0
忽略高次项：
S
2 L0
0
提高一倍
5
3、螺管式自感传感器
4AW 2 L 107 ( H ) l
特点：测量范围大，数百毫米，灵敏度低，大量程直线位移。 4、差动螺管式自感传感器