Chapter3新-1
chapter3-1 roots,stem and leaf
3.1.3 emergence and growth of roots 1.) emergence of roots
（1）实生根系(seedling root system)：由种子胚根发育
而来的根。 radicle→ the primary root→ lateral roots (or secondary roots).
须根的分类
按其功能和结构分为四类
生长根：或称轴根，是根系向 远处扩展部分，一般白色，具 吸收功能。
吸收根：主要功能是吸收以及 将吸收到的物质转化为有机物 质或运输到地上部，多为白色。
过渡根：由吸收根转化而来， 一部分转化为输导根，部分死 去。
输导根：主要功能是运送各种 营养物质和输导水分的作用。
2.) types of root system
The tap root system, also called the primary root system, is characterized by a large central axis that is larger than the lateral roots that develop from it.
主根发达，根生活力强。 绝大多数蔬菜和种子繁殖的 花卉、果树砧木多为实生根系。
（2）茎源根系(cutting root system)：利用植物营养器 官具有的再生能力，采用枝条扦插或压条繁殖，使茎上 产生不定根，由此发育成的根系称为茎源根系。茎源根 系无主根，生活力相对较弱，常为浅根。
（3）根蘖根系(layering root system)：果树中的枣、山 楂及香椿等和部分宿根花卉的根系通过产生不定芽可以 形成植株，其根系称根蘖根系。
【固定收益证券】Chapter3-1
银行利率
活期存款按季复利 定期存款存期内单利 贷款按季复利 年利率/12（月）＝月利率 月利率/30（天）＝日利率 年利率/360（天）＝日利率
n FV = (1 + r ) A (1 + r ) − 1 r
A为每期期末收付的金额，Fk为金额A在k 期后的终值，n为复利期数，r为每期利 率
0 1 2 n-1 n
年金终值：FV=F0+F1+F2+…+Fn-1 Fk=A(1+r)k FV=A+A(1+r)+A(1+r)2+…+A(1+r)n-1 FV(1+r)=A(1+r)+A(1+r)2+…+A(1+r)n FV(1+r)-FV= FV×r=A(1+r)n-A
现值与终值
终值的计算 单利终值、复利终值、年金终值 年金：在相同的间隔时间内陆续收到或付出相同 年金 金额的款项（分期付款买房、养老金发放等）。 1）普通年金（后付年金）：在各期期末收入或 付出的年金
(1 + r )n − 1 r FV = A 2）预付年金：在各期期初收入或付出的年金
例3：银行提供一笔200,000元的住房按 揭贷款，期限30年，每月月末等额还款， 年利12％，每月还款额？ 解：期数为30×12＝360 每期利率12％/12=1% 200000=A[1-(1+1%)-360]/1% A=2057.23（元）
景区开发与管理英文版Chapter 3(1)
Brand extension
9. Packaging
1
2
3
4
Providing information and signposting to help visitors find the Attraction.
Attractive entrances to attract passing trade
8. Branding
Kotler defines a brand as ‘a name, sign, symbol, or design or combination of them intended to identify the goods or services of one seller or group of sellers and to differentiate them from those of competitors’. But branding is weaker in attraction sector because: 1
Explore three levels of product Attraction and the product life cycle
Trends in attraction product
1. What is product
Product
A product is anything that can be offered to a market for attention, acquisition, use, or consumption that might satisfy a want or need. It includes phsical objects, services, persons, • The product/service mix is the combination of products and services, aimed at Product -- expanding • Product/service mix
chapter-3-1
经营负债会使使用中的自有经营资产减少而提高 RNOA. 一个公司能在多大程度上获得无息贷款用于营业 活动，它就能够在多大程度上减少其净经营资产 上的投资，从而提高其RNOA。 供应方提供的无息占款并非无成本，为什么?
2007-10-15 UIBE-BUSINESSCHOOL LEIGY 17
计算经营资产回报率ROOA：
将总资产报酬率剔除经营杠杆的影响后，就可以得 到净经营资产的报酬率（RNOA）。 在不考虑 经营杠杆的前提下，总资产报酬率就是净经营资产 报酬率。
总资产报酬率的进一步运用：对资产收益率进 行分解——杜邦分析法的核心
净收益＋利息费用＋所得税 总资产报酬率＝ 资产平均总额 销售净额 净收益＋利息费用＋所得税 = × 资产平均总额 销售净额 = 总资产周转率 × 销售收益率
金融资产报酬率：反映财务活动的盈利能力 净金融资产：用于金融投资活动的资产大于因融资
活动产生的金融负债的差额。
净金融负债：金融资产与金融负债之差
金融资产报酬率实际上是由财务杠杆效应来实现的。 财务杠杆反映了经营资产在多大程度上是由净金融 负债或普通权益融资形成的。
财 务 杠 杆 (FLEV) = 净 金 融 负 债 NFO = 普 通 股 东 权 益 C SE
金融资产报酬率
第二层次
营业边际利润率
总资产周转率
第三层次
销售毛利率
费用比率
各项资产周转率
2007-10-15
UIBE-BUSINESSCHOOL LEIGY
7
财务比率的英文缩写
财务报表项目： 收益＝综合收益 CSE＝普通股东权益 OI＝经营收益（税后） NOA＝净经营资产 NFE＝净财务费用 NFO＝净金融负债 财务比率
新思维朗文3B chapter3(1)
朗文3B Chapter3(1) Campingi.Words and phrases1.stay in a tent呆在家stay _________ _________呆在学校________ ________ _________2.cook a meal做午饭________ ________煮面条________ ________3.play hide-and-seek踢足球________ ________玩球________ ________4.boil water5.pick up rubbish捡起这本书pick up ________ ________捡起它pick ________ up捡起他们_____________________6.wash outside7.plant trees种花plant _________8.make a fire with banana leaves一片香蕉叶a banana _________生火________________________9.find more firewoodfind a book ________________look for a book __________________10.help to prepare lunch帮忙找盘子help _________ _________ ________ plates11.cook the noodles12.open the tin of pork一听 a _________ _______两听可乐two _________ _________ cola13.take out14.a strong winda heavy rain15.blow away16.taste yummy尝起来很好taste _________ii.Sentences1.Was camp fun? Yes, it was.2.We stayed in a tent.3.What did you do? We cooked a meal.4.There’s not enough firewood for tonight.5.What a lot of firewood!6.Judy and Dad bring a lot of firewood back to the camp.iii.Grammar1.Be动词过去式is-was are-were句型转换：肯定句：It was great fun.There were many books yesterday.否定句：It _________ great fun.There ________ many books yesterday.一般疑问句：_________ it great fun?________ there many books yesterday?练习：①It was rained yesterday.________________________________________________________②We were happy last summer holiday.________________________________________________________2.实义动词过去式stay-stayed cook-cooked句型转换：We cooked a meal.否定(借助助动词did+not，原来动词要还原)We cooked a meal. →We didn’t cook a meal.He stayed at home last Sunday. →一般疑问句(借助助动词did提前，原来动词还原)We cooked a meal. →Did you cook a meal? Yes, we did. No, we didn’t. He stayed at home last Sunday. →练习：①I looked for my books yesterday. (改为否定句和一般疑问句)________________________________________________________________________________________________________________②He started reading when he was five. (改为一般疑问句并作否定回答)________________________________________________________③Mr Green stopped talking just now. (对画线部分提问)________________________________________________________3.感叹句What +How +There are a lot of firewood.→What a lot of fire wood!The dog is very cute.→What a cute dog!→How cute the dog is!练习：She is a beautiful girl. (改为感叹句)____________________________________________________________4.with①和play with friends②用make a fire with banana leaves5.bring sb. sth = bring sth to sb./sp.Dad brings some firewood to the camp. =My mum brings me some presents. =这样句型结构还有：6.顺序词First Next Then Finally7.windwind 风（不可数）a strong wind 一阵大风rain 雨水（不可数）a heavy rain 一场大雨8.What shall we do now?shall为情态动词+ 动词原形Shall we go?Shall I use your pen?Shall用于第一人称9.taste +形容词(尝起来…)look +形容词(看起来)The food taste good.Your friend looks nice.Exercise1.What did you do? We __________(look) for our books.2.I __________(cook) fish yesterday.3.He __________(be) short ten years old.4.We __________(plant) trees on the 21st of January.5.Please __________(pick) up rubbish.6.__________ you happy last winter holiday? Yes, I __________.7.Beeno __________(be) little when he __________(be) a child.8.What __________ he __________(play) with last night?He __________(play) with his toys.9.I cooked the noodles and the vegetables. (改为否定句和一般疑问句)________________________________________________________________________________________________________________________10.Mum only open the tin of pork. (对画线部分提问)____________________________________________________________11.Where did you collected it? (改错)____________________________________________________________12.Judy bring a lot of firewood back to the camp. (改错)____________________________________________________________13.Mark played with Cindy. (对画线部分提问)____________________________________________________________14.完形填空I am Nancy Black. I___1__a brother, Mike. My father is a doctor and my mother is a bus driver. They don't ___2____ on Saturdays and Sundays. They sweep the floor _____3___ Saturday morning. ___4_____ Mike and I like ____5__ some magazines. Sometimes we watch TV, but my father ___6_____, he ___7__ reading a newspaper__8___my mother.( )1. A. am B. have C. has( )2. A. sleep B. work C. like( )3. A. in B. under C. on( )4. A. and B. so C. But( )5. A. reading B. looking C. buy( )6. A. don't B.doesn't C. isn't( )7. A. is B. like C. likes( )8. A. with B. and C. /。
Chapter 3-1 晶体缺陷-点缺陷、位错
杂质（异类）原子
定义： 任何纯金属中都或多或少会存在杂质, 即其它
元素, 这些原子称杂质（异类）原子
热缺陷： 热起伏促使原子脱离点阵位置而形成的点缺陷。 热缺陷的两种基本形式
弗伦克尔缺陷
肖特基缺陷
热缺陷示意图
弗兰克尔缺陷
肖特基缺陷
化合物离子晶体中的两种点缺陷
金属晶体：弗兰克尔缺陷比肖特基缺陷少得多 离子晶体：结构配位数低-弗兰克尔缺陷较常见
ρ理论
=
n理论 NA
V
M
=
4 6.022 1023
26.98
4.049 10-8 3
g
cm 3 = 2. 6997g
cm 3
空位数 cm3
ρ ρ theoretical
observed
NA
M 4.620 10 20 cm 3 Al
例5 MgO晶体的肖特基缺陷生成能为84KJ/mol，计算该晶体 1000K和1500K的缺陷浓度
平移对称性的示意图
平移对称性的破坏
②分类
点缺陷（零维缺陷）--原子尺度的偏离.
按
例：空位、间隙原子、杂质原子等
缺
陷 线缺陷（一维缺陷）--原子行列的偏离.
的
例：位错等
几 何
面缺陷（二维缺陷）--表面、界面处原子排列混乱.
形
例：表面、晶界、堆积层错、镶嵌结构等
态 体缺陷（三维缺陷）--局部的三维空间偏离理想晶体的周期性
CV ,1000
n N
exp( ΔGS RT
)
exp(
84000 8.3145 1000
) 4.096 10-5
CV ,1500
n N
ρ
( 单位晶胞原子数n )( 55.847g / mol ) ( 2.866 108 cm )3 ( 6.02 1023 / mol )
化工热力学3-1Chapter3纯流体的热力学性质计算
T T 1
p 1
T T 1
注意:可观察附录的水蒸汽表中水在恒温下H,S随p的变化
*
20
§3.2 热力学性质的计算
3.2.2 直接应用Maxwell关系式和微分能量方程求解H,S 3.2.2.3工质为理想气体时 1)H*、 S*普遍式
∵pV=RT，当p为常数时两边对T求导 p(dV/dT)=R(V/T)p=R/p V－T(V/T)p=V－TR/p=0
H T T 1 2c p d T p p 1 2 V T V T p d p(3 1 8 ) 的 积 分 式 ,P 3 2
ST T 1 2c T pd T p p 1 2 V T pd p(3 1 5 )的 积 分 式 ,P 3 1
H*
T2 T1
Esys=U+Ek+Ep=UU=Q+W、dU=dQ+dW 对于可逆过程: dQR=TdS、dWR=－pdVdU=TdS－pdV （3-1）
*
9
§3.1 热力学性质间的关系
Chapter3．纯流体的热力学性质计算
3.1.1 单相流体系统基本方程——微分能量表达式 (2)复习H、A、G定义，推导dH、dA、dG
dU = dH = dA = dG = 0
Chapter3．纯流体的热力学性质计算 概述
二、本章要解决的主要问题 1.通过学习热力学性质的基本微分方程解决可直 接测量的状态函数与不可直接测量的状态函数之 间的关系； 2.纯物质的热力学性质的计算，重点为H、S的 计算； 3.常用热力学性质数据图表的应用。
(3-8) (3-9) (3-10) (3-11)
“TV”在同一边,等式带
*
“”
14
§3.1 热力学性质间的关系
英语写作基础教程(chapter 3)01
and arranges his history books accordingly. It is odd,
but it is convenient. #
.
Assignments
Reading:
pp 41-45
Exercises:
pp 49-54 ▪ Exercise 1: Chronological order ▪ Exercise 2: Process ▪ Exercise 3: Space
(ways of developing paragraphs)
Development by Time
In telling a story or recounting an event, the easiest and clearest way is to describe things in order of time; earlier things are mentioned before later things, the first thing first and the last thing last. This method is also called chronological sequencing.
An effective paragraph
❖ 3 features of an effective paragraph: 1. A paragraph should have one, and only
one, central idea. 2. The main idea is generally expressed in
Example:
In the old days, train travel was not much fun. Back in the 1830’s, passenger coaches on western and southern roads looked like cabins on wheels. Until late in the 1840’s, passengers who wanted heat bought heated bricks from boys at the stations. There were no sleeping cars, either, until 1859, when George R. Pullman remodeled two day coaches into sleeping cars, to run from Chicago to Bloomington, Illinois. They were lighted by candles and heated by wood-burning stoves. Passengers near the stoves were too hot, and those far away were too cold. Even years later, after trains had better heating systems, passengers were often most uncomfortable. Open windows let in showers of soot and cinders; and closed windows meant stifling temperatures. Travelers reached their destinations in those days sooty, jostled, and travel-worn. #
材料力学第26讲 Chapter3-1第三章 能量法(应变能 余能)
能量方法是用有限元法解固体力学问题的重要基础。
4
能量方法用途很广：
不仅适用于线弹性问题； 也可用于非线性弹性问题； 曲杆问题；
5
本章要介绍的几种能量方法：
应变能原理－卡氏第一定理 余能原理－卡氏第二定理 虚位移原理及单位力法
6
§3–2 应变能 余能
应变能的计算：
I. 应变能
外力缓慢做功W ，无损失地转化为应变能 （不
转化成动能、热能） ，贮存于弹性体内部。
V W
7
一、 线弹性问题
1. 轴向拉压杆件应变能的计算
W 1 Fl
2
l Fl
W F 2l 2EA
F
EA
W＝V 功能原理
V
EAl2
2l
F 2l V 2 EA
5P1P2l3 48EI
23
进一步分析
21
P1
P2
12
l
l
2
2
21P16(E 2l)Il2(3l2l)458P1E l3I
l
l
2
2
12P26(E 2l)Il2(3l2l)4 58 P2 E lI3
P112 P221 ====== 功的互等定理 ======
第一组力在第二组力作用所产生位移上做的功 等于第二组力在第一组力作用所产生位移上做的功。
17
4.3 弯曲杆件应变能的计算
V
V vdV
V
1 2
dV
V
1 2E
2dV
l
A21E(M Izy)2dAdl l
A21E(M Iz )2y2dAdl
d l dx M 2 l 2EIz
八年级英语上册Chapter3DealingwithtroubleReading教案1牛津沈阳版(1)
Chapter3 Dealing with trouble Reading一、章节分析（Reading section ）（一）综述（二）本单元的阅读部分是以日记的形式讲述了一起抢劫案。
作者和他的父亲在了解案情的情况下，报警抓罪犯的过程，可以让学生得到两个启示：一、我们要在别人危难之际，勇于帮助他人。
二、危及时刻，可以尽快通知有关部门，我们无须把自己陷入困境中。
本篇阅读中还出现了一些核心词汇如： argue, deal with, dial, robbery, steal, trouble ,等也是教师教学的重点。
（二）阅读目标1知识目标学习课文中重点词、词组、句型和语法。
能力目标掌握英语日记格式和地址写法。
2情感目标教育学生遇到突发事件，要沉着冷静，有勇有谋。
（三）教学方法采用任务型教学法组织教学，通过听说，讨论等具体活动，达到教学效果。
（四）重点和难点1词汇学习1)核心词汇argue (v )争吵,争论 empty (a.) 空的crowd (n) 人群 stare (n)&(v) 瞪视,盯着看notice (v) 注意到 follow (v) 跟从,跟随action (n) 行为,举动 report (v)&(n) 报道,报告dial (v) 拨号 rob (v) 抢劫detail (n) 细节 steal (v) 偷 (steal---stole—stolen)拓展词汇argument (n)争吵 purse (n) (女用)钱包robbery (n.) 抢劫案 ) 手铐noisily (ad)吵闹地 railing (n) 栏杆permission (n)许可 aboard (adv) 在船上,到船上(火车上,飞机上等) definitely (ad)明确地2)词组：shout at 对…大喊deal with 处理、应付tourists 女游客（复数）go on 发生 at first 起先away 逃跑go down onto the ferry 走下到渡船上be afraid of 害怕get off 下（船）车well done 干得好 shop assistant 营业员教学设计（Teaching Designs）教学内容教学实施建议教学资源参考Pre-reading 1利用图片学习新单词 [链接1]2．通过讨论报纸上的抢劫案件引发学生的讨论。
Chapter3Ourschoolevents背诵总结(知识清单)-新思维小学英语三年级上册
3A Chapter 3 背诵内容一、单词：序数词1.first 第一2.second 第二3.third 第三4.fourth 第四5.fifth 第五6.eighth 第八7.ninth 第九8.tenth 第十9.eleventh 第十一10.twelfth 第十二11.thirteenth 第十三12.fourteenth 第十四13.fifteenth 第十五14.sixteenth 第十六15.seventeenth第十七16.eighteenth 第十八17.nineteenth 第十九18.twentieth 第二十19.twentyfirst 第二十一20.twentysecond 第二十二21.twentythird 第二十三22.twentyfourth 第二十四23.twentyfifth 第二十五24.twentysixth 第二十六25.twentyseventh 第二十七26.twentyeighth 第二十八27.twentyninth 第二十九28.thirtieth 第三十29.thirty first 第三十一月份1.January 一月2.February 二月3.March 三月4.April 四月5.May 五月6.June 六月7.July 七月8.August 八月9.September 九月10.October 十月11.November 十一月12.December 十二月其它1.event 事件2.webpage 网页3.diary 日记4.concert 演唱会，音乐会5.speech 演讲6.picnic 野餐7.fair 市场8.invitation 邀请（n.名词）invite 邀请（v.动词）9.calendar 日历10.both (两个)都11.stick v. 粘、贴12.still 仍然13.return 返回二、词组和句型：1.our school events 我们学校的大事2.make a webpage 做网页3.help sb. (somebody) do sth.(something) 帮助某人做某事4.an invitation for Parents’ Day 家长会的邀请（函）5.feel bad 感觉糟糕6.give the cards to Mum and Dad = give Mum and Dad the cards把卡片给爸爸妈妈7.Parents’ Day at Sunny Girls’ School 阳光女子学校的音乐会8.half past three 三点半four o’clock9.Our school fair is on the twentyfirst of December, from nine o’clockin the morning to four o’clock in the afternoon. 我们学校的义卖在12月21号，从早上9点到下午4点。
chapter3(第一课)
Lesson 5 General Enquiry & Reply 1
Specimen Letter 1 An Enquiry for Sports Shoes
Lesson 5 General Enquiry & Reply 1
At present, we are particularly interested in sports shoes. We would appreciate it if you could send us your 2015 catalogue of sports shoes in various colors, sizes and styles. Please advise us the details of your terms of payment and any special discount you are offering. And also we shall be grateful if you would send us some sample cuttings of the vamp material for our reference.
Introduction and Writing Skill
3. Indicate terms of payment, shipment, packing, quantity ,etc. Example: Terms of payment: L/C at sight.
Shipment: During September and October. 4. State validity of the offer. Example: This offer is valid for a week from today.
chapter3-1
③高聚物聚集态
晶态
非极性
因此高分子溶解比小分子要复杂得多。
极性
聚合物溶解过程的特点
a 溶解过程缓慢，且先溶胀再溶解 b 非晶态聚合物比结晶聚合物易于溶解
c 交联聚合物只溶胀，不溶解
18
3.1.1 溶解过程 3.1.1.1非晶态聚合物的溶胀和溶解
线形非晶态聚合物溶解过程分两步进行：首先溶胀(溶剂分子 和高分子的某些链段混合），然后溶解（溶剂分子和整个高 分子链的混合）。 溶解度与分子量有关。通常分子量大的，溶解度小；分子量 小的，溶解度大。 提高温度一般可以增加其溶解度；降低温度则减小其溶解度。
第3章 高分子溶液
高分子溶液：聚合物以分子状态分散在溶剂中所形 成的均相体系。 高分子溶液的分类： (A)稀溶液：浓度＜ 1%，粘度小且稳定性好，处 于热力学平衡态的真溶液； (B)高分子浓溶液：一般浓度＞ 5% ； (C)高分子的亚浓溶液 对于稀溶液，随着浓度的提高，孤立存在的无规线 团分子开始相互接触，继而交叠，形成所谓的“亚 浓溶液”。
例：聚丙烯腈
混合溶剂的选择：
单一组分的溶剂对高聚物的溶解效果 不好，可以考虑使用混合溶剂： δ混＝δ1Φ1＋δ2Φ2 Φ1，Φ2：两种纯溶剂的体积分数； δ1, δ2：两种纯溶剂的溶度参数。
(三) “高分子－溶剂相互作用参数 1小于 1/2 ” 原则
高分子－溶剂相互作用参数 1反映高分子 与溶剂混合时相互作用能的变化。
1 ＜ 1/2 聚合物在溶剂中溶解 1 =1/2 θ溶液状态
1 2
1 ＞ 1/2 聚合物在溶剂中不溶解, 或者会从溶液中 沉淀析出
小结
1名词：高分子溶液；溶度参数 。 2掌握聚合物溶解过程的特点，以及典 型的几种聚合物的良溶剂。 3掌握溶度参数的测定方法以及选择混 合溶剂溶解聚合物的计算。 4熟练掌握对聚合物溶解能力的判定原 则。
Chapter 3-1(week 3-1)解
Chapter 3-1一. 选择题：1. 在1:100万航图上，10cm相当于地面长（ A ）A. 100kmB. 10kmC. 1km2. 地图比例尺有哪三种表示形式？（ B ）A. 数字、文字、分式B. 数字、文字、图解C. 数字、分式、图解3. 地图存在的三种失真是（ C ）A. 角度、长度、体积B. 角度、面积、体积C. 角度、长度、面积4. Lambert conformal conic projection charts are the charts without the distortion of（ A ）.A. angleB. distanceC. area5. 没有距离失真的航图叫做（ A ）A. 等距投影图B. 等角投影图C. 等积投影图6. On Lambert chars, can a straight line be flown without changing heading at regular intervals?（ B ）A. YesB. NoC. I don’t know.7. 墨卡托投影图属于（ B ）A. 等距投影图B. 等角投影图C. 等积投影图8. 世界航图的比例尺是（ C ）A. 1:10万B. 1:50万C. 1:100万二. 填空题：1. 地图三要素指的是地图比例尺、地图投影、地图符号。
2. 某跑道长2km，画到1:10万地图上的长度是2cm 。
3. 1:100万世界航图不存在角度失真。
4. The Lambert Conformal Conic projection is used widely for the production of WAC.5. WAC stands for World Aeronautical Chart .WCA stands for Wind Correction Angle .6. On Lambert Charts, a straight line drawn between any two points represent a great circle ,while on Mercator Charts, it represents a rhumb line .三. 问答题：1. 请简述兰伯特投影的特点。
Chapter 3_1
Chapter 3TOM presented himself before Aunt polly, who was sitting by an open window in a pleasant rearward apartment, which was bedroom, breakfast-room, dining-room, and library, combined. The balmy summer air, the restful quiet, the odor of the flowers, and the drowsing murmur of the bees had had their effect, and she was nodding over her knitting -- for she had no company but the cat, and it was asleep in her lap. Her spectacles were propped up on her gray head for safety. She had thought that of course Tom had deserted long ago, and she wondered at seeing him place himself in her power again in this intrepid way. He said: "Mayn't I go and play now, aunt?""What, a'ready? How much have you done?""It's all done, aunt.""Tom, don't lie to me -- I can't bear it.""I ain't, aunt; it is all done."Aunt polly placed small trust in such evidence. She went out to see for herself; and she would have been content to find twenty per cent. of Tom's statement true. When she found the entire fence whitewashed, and not only whitewashed but elaborately coated and recoated, and even a streak added to the ground, her astonishment was almost unspeakable. She said: "Well, I never! There's no getting round it, you can work when you're a mind to, Tom." And then she diluted the compliment by adding, "But it's powerful seldom you're a mind to, I'm bound to say. Well, go 'long and play; but mind you get back some time in a week, or I'll tan you."She was so overcome by the splendor of his achievement that she took him into the closet and selected a choice apple anddelivered it to him, along with an improving lecture upon the added value and flavor a treat took to itself when it came without sin through virtuous effort. And while she closed with a happy Scriptural flourish, he "hooked" a doughnut.Then he skipped out, and saw Sid just starting up the outside stairway that led to the back rooms on the second floor. Clods were handy and the air was full of them in a twinkling. They raged around Sid like a hail-storm; and before Aunt polly could collect her surprised faculties and sally to the rescue, six or seven clods had taken personal effect, and Tom was over the fence and gone. There was a gate, but as a general thing he was too crowded for time to make use of it. His soul was at peace, now that he had settled with Sid for calling attention to his black thread and getting him into trouble.Tom skirted the block, and came round into a muddy alleythat led by the back of his aunt's cow-stable. He presently got safely beyond the reach of capture and punishment, and hastened toward the public square of the village, where two "military" companies of boys had met for conflict, according to previous appointment. Tom was General of one of these armies, Joe Harper (a bosom friend) General of the other. These two great commanders did not condescend to fight in person -- that being better suited to the still smaller fry -- but sat together on an eminence and conducted the field operations by orders delivered through aides-de-camp. Tom's army won a great victory, after a long and hard-fought battle. Then the dead were counted, prisoners exchanged, the terms of the next disagreement agreed upon, and the day for the necessary battle appointed; after which the armies fell into line and marched away, and Tom turned homeward alone.As he was passing by the house where Jeff Thatcher lived, he saw a new girl in the garden -- a lovely little blue-eyed creature with yellow hair plaited into two long-tails, white summer frock and embroidered pantalettes. The fresh-crowned hero fell without firing a shot. A certain Amy Lawrence vanished out of his heart and left not even a memory of herself behind. He had thought he loved her to distraction; he had regarded his passion as adoration; and behold it was only a poor little evanescent partiality. He had been months winning her; she had confessed hardly a week ago; he had been the happiest and the proudest boy in the world only seven short days, and here in one instant of time she had gone out of his heart like a casual stranger whose visit is done.He worshipped this new angel with furtive eye, till he saw that she had discovered him; then he pretended he did not knowshe was present, and began to "show off" in all sorts of absurd boyish ways, in order to win her admiration. He kept up this grotesque foolishness for some time; but by-and-by, while he was in the midst of some dangerous gymnastic performances, he glanced aside and saw that the little girl was wending her way toward the house. Tom came up to the fence and leaned on it, grieving, and hoping she would tarry yet awhile longer. She halted a moment on the steps and then moved toward the door. Tom heaved a great sigh as she put her foot on the threshold. But his face lit up, right away, for she tossed a pansy over the fence a moment before she disappeared.The boy ran around and stopped within a foot or two of the flower, and then shaded his eyes with his hand and began to look down street as if he had discovered something of interest going on in that direction. presently he picked up a straw and begantrying to balance it on his nose, with his head tilted far back; and as he moved from side to side, in his efforts, he edged nearer and nearer toward the pansy; finally his bare foot rested upon it, his pliant toes closed upon it, and he hopped away with the treasure and disappeared round the corner. But only for a minute -- only while he could button the flower inside his jacket, next his heart -- or next his stomach, possibly, for he was not much posted in anatomy, and not hypercritical, anyway. He returned, now, and hung about the fence till nightfall, "showing off," as before; but the girl never exhibited herself again, though Tom comforted himself a little with the hope that she had been near some window, meantime, and been aware of his attentions. Finally he strode home reluctantly, with his poor head full of visions.All through supper his spirits were so high that his auntwondered "what had got into the child." He took a good scolding about clodding Sid, and did not seem to mind it in the least. He tried to steal sugar under his aunt's very nose, and got his knuckles rapped for it. He said:"Aunt, you don't whack Sid when he takes it.""Well, Sid don't torment a body the way you do. You'd be always into that sugar if I warn't watching you."presently she stepped into the kitchen, and Sid, happy in his immunity, reached for the sugar-bowl -- a sort of glorying over Tom which was wellnigh unbearable. But Sid's fingers slipped and the bowl dropped and broke. Tom was in ecstasies. In such ecstasies that he even controlled his tongue and was silent. He said to himself that he would not speak a word, even when his aunt came in, but would sit perfectly still till she asked who did the mischief; and then he would tell, and therewould be nothing so good in the world as to see that pet model "catch it." He was so brimful of exultation that he could hardly hold himself when the old lady came back and stood above the wreck discharging lightnings of wrath from over her spectacles. He said to himself, "Now it's coming!" And the next instant he was sprawling on the floor! The potent palm was uplifted to strike again when Tom cried out:"Hold on, now, what 'er you belting me for? -- Sid broke it!"Aunt polly paused, perplexed, and Tom looked for healing pity. But when she got her tongue again, she only said:"Umf! Well, you didn't get a lick amiss, I reckon. You been into some other audacious mischief when I wasn't around, like enough."Then her conscience reproached her, and she yearned to saysomething kind and loving; but she judged that this would be construed into a confession that she had been in the wrong, and discipline forbade that. So she kept silence, and went about her affairs with a troubled heart. Tom sulked in a corner and exalted his woes. He knew that in her heart his aunt was on her knees to him, and he was morosely gratified by the consciousness of it. He would hang out no signals, he would take notice of none. He knew that a yearning glance fell upon him, now and then, through a film of tears, but he refused recognition of it. He pictured himself lying sick unto death and his aunt bending over him beseeching one little forgiving word, but he would turn his face to the wall, and die with that word unsaid. Ah, how would she feel then? And he pictured himself brought home from the river, dead, with his curls all wet, and his sore heart at rest. How she would throw herself upon him, and how her tears wouldfall like rain, and her lips pray God to give her back her boy and she would never, never abuse him any more! But he would lie there cold and white and make no sign -- a poor little sufferer, whose griefs were at an end. He so worked upon his feelings with the pathos of these dreams, that he had to keep swallowing, he was so like to choke; and his eyes swam in a blur of water, which overflowed when he winked, and ran down and trickled from the end of his nose. And such a luxury to him was this petting of his sorrows, that he could not bear to have any worldly cheeriness or any grating delight intrude upon it; it was too sacred for such contact; and so, presently, when his cousin Mary danced in, all alive with the joy of seeing home again after an age-long visit of one week to the country, he got up and moved in clouds and darkness out at one door as she brought song and sunshine in at the other.He wandered far from the accustomed haunts of boys, and sought desolate places that were in harmony with his spirit.A log raft in the river invited him, and he seated himself on its outer edge and contemplated the dreary vastness of the stream, wishing, the while, that he could only be drowned, all at once and unconsciously, without undergoing the uncomfortable routine devised by nature. Then he thought of his flower. He got it out, rumpled and wilted, and it mightily increased his dismal felicity. He wondered if she would pity him if she knew? Would she cry, and wish that she had a right to put her arms around his neck and comfort him? Or would she turn coldly away like all the hollow world? This picture brought such an agony of pleasurable suffering that he worked it over and over again in his mind and set it up in new and varied lights, till he wore it threadbare. At last he rose up sighing anddeparted in the darkness.About half-past nine or ten o'clock he came along the deserted street to where the Adored Unknown lived; he paused a moment; no sound fell upon his listening ear; a candle was casting a dull glow upon the curtain of a second-story window. Was the sacred presence there? He climbed the fence, threaded his stealthy way through the plants, till he stood under that window; he looked up at it long, and with emotion; then he laid him down on the ground under it, disposing himself upon his back, with his hands clasped upon his breast and holding his poor wilted flower. And thus he would die -- out in the cold world, with no shelter over his homeless head, no friendly hand to wipe the death-damps from his brow, no loving face to bend pityingly over him when the great agony came. And thus she would see him when she looked out upon the glad morning, and oh! would shedrop one little tear upon his poor, lifeless form, would she heave one little sigh to see a bright young life so rudely blighted, so untimely cut down?The window went up, a maid-servant's discordant voice profaned the holy calm, and a deluge of water drenched the prone martyr's remains!The strangling hero sprang up with a relieving snort. There was a whiz as of a missile in the air, mingled with the murmur of a curse, a sound as of shivering glass followed, and a small, vague form went over the fence and shot away in the gloom. Not long after, as Tom, all undressed for bed, was surveying his drenched garments by the light of a tallow dip, Sid woke up; but if he had any dim idea of making any "references to allusions," he thought better of it and held his peace, for there was danger in Tom's eye.Tom turned in without the added vexation of prayers, and Sid made mental note of the omission.。
chapter3-1电力系统的频率特性
f
A
C
fe f1
B
1
P2
PL
P1 P'
P2
P
P
' 2
P2 o
P1
P
' 1
图 3-6 两台发电机并联运行情况
P1 P2 PL
第一节 电力系统的频率特性
系统频率稳定在 f 1 ： 1 号机组的负荷增加了 P1 2 号机组的负荷增加了 P 2 两台机组增量之和等于 P L 可得
解 由（3-3）式可求出当频率下降到 47Hz 时 系统的负荷为
Pl* a0 a1 f * a2 f * an f *
2 n
0.3 0.4 0.94 0.1 0.942 0.2 0.943
0.3 0.376 0.088 0.166 0.930
P 1 G* R f *
K G* ——发电机的功率-频率特性系数，或原动机的单位调节功率。
一般发电机的调差系数或单位调节功率，可采用下列数值： 对汽轮发电机组 对水轮发电机组
R* (4 ~ 6)% 或 K G* 16.6 ~ 25 ； R* (2 ~ 4)% 或 K G* 25 ~ 50 。
第三章 电力系统频率及有功功率的自动调节
（1）频率对电力用户的影响 1）电力系统频率变化会引起异步电动机转速变化，这会使得电动 机所驱动的加工工业产品的机械的转速发生变化。有些产品（如纺织和 造纸行业的产品）对加工机械的转速要求很高，转速不稳定会影响产品 质量，甚至会出现次品和废品。 2） 系统频率波动会影响某些测量和控制用的电子设备的准确性和性 能， 频率过低时有些设备甚至无法工作。 这对一些重要工业和国防是不能 允许的。 3） 电力系统频率降低将使电动机的转速和输出功率降低， 导致其所 带动机械的转速和出力降低，影响电力用户设备的正常运行。
Chapter 3 Unit 1-Liaison Interpreting
B: Excellent! What about visits to Shanghai Free Trade Zone? A: 根据您的要求，我们把您访问中国（上海）自由贸易试验区的时间安排在后
天上午。届时您可以有充足的时间了解洽谈。而您的回城飞机正好在后天晚上， 到时候我们直接把您送到机场。
9
© ZHU Peifen, ZHOU Yuan
INTERPRETING PRACTICE
场景一：机场迎宾 Greetings at the Airport A: 先生，请问您是从西雅图来的琼斯先生吗？
B: Yes, I am David Jones from Seattle, U.S.A.. If I'm not mistaken, you must be Miss Zhou from Datong Group.
BUSINESS ENGLISH INTERPRETING 商务英语口译
朱佩芬 周媛
CHAPTER THREE
UNIT ONE
Liaison Interpreting
© ZHU Peifen, ZHOU Yuan
LEARNING OBJECTIVES
After learning this chapter, students should be able to: know different categories of liaison interpreting know the requirements for interpreters be familiar with key words and phrases do liaison interpreting
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传感器测量动态信号的能力用动态特性表示。动态
特性是指传感器测量动态信号时，输出对输入的响应特
性。传感器动态特性的性能指标可以通过时域、频域以
及试验分析的方法确定，其动态特性参数如：最大超调
量、上升时间、调整时间、频率响应范围、临界频率等。
开始 前页 后页 结束
动特性中输出量与输入量的关系不是一个定值，而是时间的函
随着微电子学、微细加工技术和集成化工艺等方面的
发展，出现了多种集成化传感器。这类传感器或是同一功 能的多个敏感元件排列成线性、面型的阵列型传感器；或 是多种不同功能的敏感元件集成一体，成为可同时进行多 种参数测量的传感器；或是传感器与放大、运算、温度补
偿等电路集成一体具有多种功能——实现了横向和纵向的
接对运动部件的实际位置进行检测。
位置控制单元 CNC 插补 指令 + 位置控制调节器
速度控制单元 +
-
速度控制 调节与驱动
机械执行部件
实际位 置反馈
实际速 度反馈
电机
检测与反馈单元
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3.1 传感器组成、分类及特性
1、定义：能够感受规定的被测量并按一定规律转换成可用
输出信号的器件或装置。（GB7665—87）
电阻应变计的结构
电阻应变计主要由电阻敏感栅、基底和面胶（或覆盖层）、 粘结剂、引出线五部分组成。电阻应变计的结构如图所示。
4 2
5
3 1
图 电阻应变计的构造 1—敏感栅；2—引出线；3—粘结剂（未示出）；4—覆盖层；5—基底
二、传感器的基本特性
(3)、迟滞 传感器在正（输入量增大）反（输入量减小）行 程中，输出——输入特性曲线不重合的程度称为迟滞， 迟滞误差一般以满量程输出的百分数表示
Hm 100 %
H
yFS
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迟滞大小用最大偏差或最大偏差的一半与满量程输出值
的百分比表示
H (1 / 2)( H max / y FS ) 100 %
由于空间的限制或者其他原因,转换电路常装入电箱中。 然而，因为不少传感器要在通过转换电路后才能输出电 信号，从而决定了转换电路是传感器的组成环节之一。
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由于机电一体化产品系统中的信号传输与处理都
是采用电子元器件来实现的，因此，传感器的作用
是敏感与变换：对被测对象敏感，以完成对被测对
态特性的主要技术指标有：线性度、灵敏度、迟滞
和重复性等。
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取决于传感器本身，可通过传感器本身的改善来加以抑 制，有时也可以对外界条件加以限制。
外界影响
冲击与振动 电磁场 输入 温度 供电
传感器
输出
线性 滞后
各种干扰稳定性 温漂 稳定性(零漂) 分辨率
重复性 灵敏度
衡量传感器特 性的主要技术 指标
转换元件：敏感元件的输出就是它的输入，它把输入 转换成电路参量。 基本转换电路：上述电路参数接入基本转换电路（简 称转换电路），便可转换成电量输出。 开始 前页 后页 结束
实际上，有些传感器很简单，有些则较复杂，大多数 是开环系统，也有些是带反馈的闭环系统。 最简单的传感器由一个敏感元件(兼转换元件)组成，它 感受被测量时直接输出电量，如热电偶。有些传感器由 敏感元件和转换元件组成，没有转换电路，如压电式加 速度传感器，其中质量块m是敏感元件，压电片（块） 是转换元件。有些传感器，转换元件不只一个，要经过 若干次转换。
误差因素
开始 前页 后页 结束 传感器输入输出作用图
二、传感器的基本特性
(1)、线性度
传感器的线性度是指传感器实际输出—输入 特性曲线与理论直线之间的最大偏差与输出满度 值之比，即
γL Δmax 100% yFS
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几种直线拟合方法 (a) 理论拟合 (b) 过零旋转拟合 (c) 端点连线拟合 (d) 端点平移拟合
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实例一 电阻应变计
电阻应变计是根据应变—电阻效应，将给测试件的应变
量转换成电阻变化量的敏感元件。它不仅直接作为应力、应
变测量的传感器而且可以与弹性元件组合构成力、压力、称
重、位移、扭矩、振动、加速度等多种专用式传感器，广泛 应用于机械、交通、建筑、化工和电力等行业。
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感应式 流量表
称重 传感器
CCD 传感 器
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压阻式液位 传感器
温度传感器
光敏传感器
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风力参数 传感器
地震检波器
反射式光 敏传感器
超声 传感器
磁、气、力 敏传感器
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例
粮仓温度、湿度检测
无论是金属粮仓还是土仓，为防止霉变，粮食都是分 层存放，仓内温度和湿度不能过高，为此，需在各层安放 温湿度传感器进行检测。装有温湿度探头的粮仓示意图如 下。 将各层探头输出接至温湿度巡检仪上，通过巡检仪监 视器监视各点温湿度情况。通过通风口保持温湿度在要求 范围内。
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重复性指在同一工作条件下，输入量按同一方向在全测量范围 内连续变动多次所得特性曲线的不一致性。重复性误差属于随机误
差, 常用标准偏差表示, 也可用正反行程中的最大偏差表示, 即
( 2 ~ 3) rR 100 % YFS 1 Rmax rR 100 % 2 YFS
机电一体化技术
胡红生 邮箱：hhs999@
第3章 传感与检测系统设计
知识点：
传感器的组成、分类、发展趋势及选用原则 常见信号转换和放大电路 信号处理电路
信号接口电路设计
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在像我们人类这样的生物系统中，动作控制过程如图所 示。先是通过眼、耳、皮肤等感觉器官从外界接受各种各样的
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即使是同类传感器, 拟合直线不同, 其线性度也是
不同的。 选取拟合直线的方法很多, 用最小二乘法求
取的拟合直线的拟合精度最高。
（1） 拟合直线方程
y=k+b x
设有n对测量数据（xi,yi）, 用直线方程y= k +bx 拟合, 根据测量数据值, 求方程中系数k 、b的最佳 估计值。 可应用最小二乘法原理, 使各测量数据点yi与直 线输出偏差的平方和为最小。
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能将各种非电物理量转换成电量的传感器及其信
号处理技术、接口技术已成为机电一体化技术系统中
不可缺少的组成部分。
检测传感器种类很多，而在机电一体化产品中，
控制系统的控制对象主要是伺服驱动单元和执行机构，
传感器主要用于检测位移、速度、加速度、运动轨迹
以及机器操作与加工过程参数等机械运动参数。
材料、采用新工艺，并以此研制出具有新原理的新型
物性型传感器，这是发展高性能、多功能、低成本和 小型化传感器的重要途径。
在半导体硅材料发现力、热、光、磁、气体等物理量都会使 其性能改变,制成力敏、热敏、光敏、磁敏气敏等敏感元件。
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三、传感器的发展方向
2. 传感器的集成化和多功能化
感器在机电一体化设备中是不可缺少的组成却分。它是整个设备
的感觉器官，监视监测着整个设备的工作过程，使其保持最佳工 作状况，同时可用作数显装置。
在闭环伺服系统中，传感器又用作位置环的检测反馈元件， 其性能直接影响到工作机械的运动性能、控制精度和智能水平， 因而要求传感器灵敏度高、动态特性好、特别要求其稳定可靠、 抗干扰性强且能适应不同环境。
装置(常用伺服电机)或丝杠引出，采样旋转角度进
行检测，不是直接检测运动部件的实际位置。
位置控制单元 CNC 插补 指令 + 位置控制调节器
速度控制单元 +
-
速度控制 调节与驱动
机械执行部件
实际位 置反馈
实际速 度反馈
电机
检测与反馈单元
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全闭环数控系统
全闭环数控系统的位置采样点如图的虚线所示，直
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装有温湿度探头的粮仓示意图
探 头 通 风 口 通 风 口 通 风 口
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2 传感器的组成
通常传感器有敏感元件、转换元件和转换电路三部分组成。
被测量
敏感元件
转换元件 辅助电源
基本转换电路
电量
敏感元件是直接感受被测量，并输出与被测量成确定 关系的某一物理量的元件。
传感器
二值型
电阻型（电位器，电阻应变片）
电量 模拟型 电压，电流型（热电偶,太阳能电池）
电感，电容型（可变电容）
计数型（二次型+计数型）
数字型
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代码型（旋转编码器，磁尺）
二、传感器的基本特性
1. 传感器的静态特性
传感器的静态特性是指当被测量处于稳定状态 下，传感器的输入与输出值之间的关系。传感器静
数。输出量随输入量的频率的变化而变化。表征传感器动特性输 入量与输出量的关系方法是微分方程和传递函数。
标准输入有三种：
正弦变化的输入 阶跃变化的输入 线性输入
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三、传感器的发展方向
1. 新型传感器的开发
鉴于传感器的工作机理是基于各种效应和定律，由 此启发人们进一步发现新现象、采用新原理、开发新
象的信号采取；将被测非电量变换成电量。传感器
输出的电信号经过调理和接口输入微机分析处理， 提取有用的信息，再通过控制系统、驱动系统与执 行机构，对机电一体化产品系统实施自动控制。
பைடு நூலகம்
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3、分类