简明教程-第6章

理论力学简明教程第六章答案

第六章分析力学滔滔长江东逝水，浪花淘尽英雄。

达朗贝尔，拉格朗日，哈密顿等许多前贤相聚于此“力学论剑”，其“冲击波”使非线性问题也不攻自破。

长江后浪推前浪，你或许在此能够加倍“忘乎因此‘。

微分方程将叱咤风云。

[要点分析与总结]1虚功原理：（平稳时）理想条件下，力学系的平稳条件是各质点上的主动力所作的虚功之和为零：10ni i i W F r δδ==•=∑用广义坐标来表述：310n ii i x W F q q ααδδ=∂==∂∑ 2达朗贝尔原理（动力学下的虚功原理）： 1()0ni i i i i W F m r r δδ==-•=∑〈析〉r δ，W δ均是在时刻未转变（0dt =）时所假想的量，而广义坐标a q 能够是角度，长度或其它的独立的坐标变量。

3拉格朗日方程()d T TQ dt q q ααα∂∂-=∂∂ (1,2,3,,)a s =在保守力下，取拉氏数 L T V =-方程为：()0d L L dt q q αα∂∂-=∂∂ 假设拉氏数中L 不显含广义坐标q β，那么：0Lq β∂=∂ 即循环积分： Lp const q ββ∂==∂ 4微振动非线性系统在小角度近似下，对拉氏方程的应用 5哈密顿函数与正那么方程（1）哈密顿函数1(,,)sH p q t L p q ααα==-+∑式中T Lp q q ααα∂∂==∂∂为广义坐标动量（2）正那么方程Hq P Hp q H Lt tαααα∂=∂∂=-∂∂∂=-∂∂ (1,2,3,,)a s =假设哈氏函数H 中不显含广义坐标q β，那么：0Hp q ββ∂=-=∂ 即：循环积分 Tp const q ββ∂==∂ 在稳固条件下（H 中不显含t ），12sp q T ααα==∑那么有能量积分：H T V =+6泊松括号1[,]()sG H G HG H q p p q ααααα=∂∂∂∂=-∂∂∂∂∑ 7哈密顿原理与正那么变换（1）哈密顿原理保守力系下：210t t Ldt δ=⎰概念：21t t S Ldt =⎰为主函数（3）正那么变换通过某种变数的变换，找到新的函数*H ，使正那么方程的形式不变（相当于坐标变换）。

《证券投资学简明教程》练习题及参考答案第6章

一、判断题1．债券是发行人筹措资金的重要手段，投资债券的投资者与发行人之间是债权债务关系。

答案：是2．地方政府债券具有本金平安、收益稳定的特点，投资地方政府债券的投资者是不用承当信用风险的。

答案：非3．任何公司债券都存在着信用风险，但也有某些公司债券的平安性不低于地方政府债券甚至高于某些政府债券。

答案：是4．投资者投资于某固定利率债券，那么在投资时就能确定未来现金流的数量。

答案：是5．债券的定价模型尽管因债券类型不同而有不同的形式，但定价的原理都是一样的。

答案：是6．债券的票面利率与市场利率之间的关系对债券发行价格的影响为：假设债券发行时，债券的票面利率低于市场利率，债券将溢价发行。

答案：非7．在经济高速开展阶段，企业既是债券的供给者，又是债券的需求者，所以这个阶段的债券价格变动方向很难确定。

答案：非8．债券的市场价格与到期收益率之间是反方向变动的关系，对于投资者来说，当预期市场利率将下降时，应该及时将债券售出。

答案：非9．当债券的市场价格大于债券的内在价值时，投资者应该选择卖出该债券。

答案：是10．债券信用评级的对象很广泛，包括在国内市场发行的中央政府债券、地方政府债券、金融债券和公司债券等。

答案：非12．期限结构预期说认为利率的期限结构是由人们对未来市场利率变动的预期决定的，并认为市场一致预期的利率是实际利率。

答案：非13、股票价格指数是反映股票市场价格平均水平和变动趋势的指标，是灵敏反映社会经济形势的指示器。

答案：是14．股票的市场价值一定大于股票的票面价值。

答案：非15．公司的经营状况应该与公司股票的市场价格成正相关的关系，即公司经营好的，股票价格一定上升。

答案：非16．股价平均数反映市场股票价格的相对水平。

答案：非17．应用简单算术股价平均数计算平均股价，当发生样本股拆股、送股等情况时，股价平均数就会失去真实性、连续性和时间数列上的可比性。

答案：是18．股价指数用以反映市场股票价格的相对水平，它先确定一个基期，将基期股价或市价总值作为基期值，并据此计算以后各期股价或市价总值的指数值。

物理化学简明教程习题答案

第一章气体的pVT性质1.1 物质的体膨胀系数与等温压缩率的定义如下试推出理想气体的，与压力、温度的关系。

解：根据理想气体方程1.2 0℃，101.325kPa的条件常称为气体的标准状况，试求甲烷在标准状况下的密度。

解：将甲烷(Mw =16.042g/mol)看成理想气体： PV=nRT , PV =mRT/ Mw甲烷在标准状况下的密度为=m/V= PMw/RT=10116.042/8.314515(kg/m3)=0.716 kg/m31.3 一抽成真空的球形容器，质量为25.0000g充以4℃水之后，总质量为125.0000g。

若改充以25℃，13.33 kPa的某碳氢化合物气体，则总质量为 25.0163g。

试估算该气体的摩尔质量。

水的密度1g·cm3计算。

解：球形容器的体积为V=（125-25）g/1 g.cm-3=100 cm3将某碳氢化合物看成理想气体：PV=nRT , PV =mRT/ MwMw= mRT/ PV=(25.0163-25.0000)×8.314×298.15/(13330×100×10-6)M w =30.31(g/mol)1.4 两个容积均为V的玻璃球泡之间用细管连结，泡内密封着标准状态下的空气。

若将其中的一个球加热到 100℃，另一个球则维持 0℃，忽略连接细管中气体体积，试求该容器内空气的压力。

解：由题给条件知，（1）系统物质总量恒定；（2）两球中压力维持相同。

标准状态：因此，1.5 0℃时氯甲烷（CH 3Cl ）气体的密度ρ随压力的变化如下。

试作p p-ρ图，用外推法求氯甲烷的相对分子质量。

1.6 今有20℃的乙烷－丁烷混合气体，充入一抽成真空的200 cm3容器中，直至压力达101.325 kPa，测得容器中混合气体的质量为0.3897 g。

试求该混合气体中两种组分的摩尔分数及分压力。

解：将乙烷(M w=30g/mol,y1),丁烷(M w=58g/mol,y2)看成是理想气体:PV=nRT n=PV/RT=8.3147⨯10-3mol(y1⨯30+(1-y1) ⨯58)⨯8.3147⨯10-3=0.3897y1=0.401 P1=40.63kPay2=0.599 P2=60.69kPa1.7 如图所示，一带隔板的容器内，两侧分别有同温同压的氢气与氮气，二者均可视为理想气体。

物理学简明教程马文蔚等高教出版社

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简明英语语言学教程第二版第6章答案

Chapter 6 PRAGMATICS1. What does pragmatics study? How does it differ from traditional semantics?答：Generally speaking, pragmatics is the study of meaning in the context. It studies meaning in a dynamic way and as a process. In order to have a successful communication, the speaker and hearer must take the context into their consideration so as to effect the right meaning and intention. The development and establishment pragmatics in 1960s and 1970s resulted mainly from the expansion of the study semantics. However, it is different from the traditional semantics. The major difference between them lies in that pragmatics studies meaning in a dynamic way, while semantics studies meaning in a static way. Pragmatics takes context into consideration while semantics does not. Pragmatics takes care of the aspect of meaning that is not accounted for by semantics.2. Why is the notion of context essential in the pragmatic study of linguistic communication? 答：The notion of context is essential to the pragmatic study of language. It is generally considered as constituted by the knowledge shared by the speaker and the hearer. Various continents of shared knowledge have been identified, e.g. knowledge of the language they use, knowledge of what has been said before, knowledge about the world in general, knowledge about the specific situation in which linguistic communication is taking place, and knowledge about each other. Context determines the speaker's use of language and also the heater's interpretation of what is said to him. Without such knowledge, linguistic communication would not be possible, and without considering such knowledge, linguistic communication cannot be satisfactorily accounted for in a pragmatic sense. Look at the following sentences:(1) How did it go?(2) It is cold in hem.(3) It was a hot Christmas day so we went down to the beach in the afternoon and had agood time swimming and surfing.Sentence (1) might be used in a conversation between two students talking about an examination, or two surgeons talking about an operation, or in some other contexts; (2) might be said by the speaker to ask the hearer to turn on the heater, or leave the place, or to put on more clothes, or to apologize for the poor condition of the room, depending on the situation of context; (3) makes sense only ii the hearer has the knowledge that Christmas falls in summer in the southern hemisphere.3. How are sentence meaning and utterance meaning related, and how do they differ?答： A sentence is a grammatical concept, and the meaning of a sentence is often studied as the abstract, intrinsic property of the sentence itself in terms of predication. But if we think of a sentence as what people actually utter in the course of communication, it becomes an utterance, and it should be considered in the situation in which it is actually uttered (or used). So it is impossible to tell if “The dog is barking” is a sentence or an utterance. It can be either. It all depends on how we look at it and how we are going to analyze it. If we take it as a grammatical unit and consider it as a self-contained unit in isolation from context, then we are treating it as a sentence. If we take it as something a speaker utters in a certain situation with a certain purpose, then we are treating it as an utterance.Therefore, while the meaning of a sentence is abstract, and decontextualized, that of anutterance is concrete, and context-dependent. The meaning of an utterance is based on sentence meaning; it is the realization of the abstract meaning of a sentence in a real situation of communication, or simply in a context. Now, take the sentence "My bag is heavy" as an example. Semantic analysis of the meaning of the sentence results in the one-place predication BAG (BEING HEA VY). Then a pragmatic analysis of the utterance meaning of the .sentence varies with the context in which it is uttered. For example, it could be uttered by a speaker as a straightforward statement, telling the hearer that his bag is heavy. It could also be intended by the speaker as an indirect, polite request, asking the hearer to help him carry the bag. Another possibility is that the speaker is declining someone's request for help. All these are possible interpretations of the same utterance “M y bag is heavy”. How it is to be underst ood depends on the context in which it is uttered and the purpose for which the speaker utters it.While most utterances take the form of grammatically complete sentences, some utterances do not, and some cannot even be restored to complete sentences.4. Try to think of contexts in which the following sentences can be used for other purposes than just stating facts:a) The room is messy.b) Oh, it is raining!c) The music of the movie is good.d) You have been keeping my notes for a whole week now.答：a) A father entered his son’s room and found it is very messy. Then when he said, “The room is messy,” he was blaming his son for not tidying it up.b) A son asked his father to play with him outside. So when the father said, “Oh, it’s raining”,he meant they couldn’t play outside.c) Two persons just watched a movie and had a discussion of it. One person sai d, “The story ofthe movie is very moving”, so wh en the other person sai d, “The music of the movie is good”, he me ant he didn't think the story of the movie was good.d) A person wanted his notes bac k, so when he said, “you ha ve been keeping my notes for awhole wee k now”, he was demanding the return of his notes.5. According to Austin, what are the three acts a person is possibly performing while making an utterance. Give an example.答：According to Austin's new model, a speaker might be performing three acts simultaneously when speaking: locutionary act, illocutionary act, and perlocutionary act.A locutionary act is the act of uttering words, phrases, clauses. It is the act of conveying literal meaning by means of syntax, lexicon and phonology. An illocutionary act is the act of expressing the speaker’s intention; it is the act performed in saying something. A perlocutionary act is the act performed by or resulting from saying something; it is the consequence of, or the change brought about by the utterance; it is the act performed by saying something. Let's look at an example:You have left the door wide open.The locutionary act performed by the speaker is his utterance of the wo rds “you”, “have”, “door”, “open”, etc. thus expressing what the words literally mean.The illocutionary act performed by the speaker is that by making such an utterance he has expressed his intention of speaking, i.e. asking someone to close the door, or making acomplaint, depending on the context.The perlocutionary act refers to the effect of the utterance. If the hearer gets the speaker's message and sees that the speaker means to tell him to close the door, the speaker has successfully brought about the change in the real world he has intended to; then the perlocutionary act is successfully performed.6. What are the five types of illocutionary speech acts Searle has specified? What is theillocutionary point of each type?答：(1) representatives: stating or describing, saying what the speaker believes to be true(2) directives: trying to get the hearer to do something(3) commissives: committing the speaker himself to some future course of action(4) expressives: expressing feelings or attitude towards an existing(5) declarations: bringing about immediate changes by saying somethingThe illocutionary point of the representatives is to commit the speaker to something's being the case, to the truth of what has been said, in other words, when performing an illocutionary act of representative, the speaker is making a statement or giving a description which he himself believes to be true. Stating, believing, sweating, hypothesizing are among the most typical of the representatives.Directives ate attempts by the speaker to get the hearer to do some- thing. Inviting, suggesting, requesting, advising, wanting, threatening and ordering are all specific instances of this class.Commissives are those illocutionary acts whose point is to commit the speaker to some future course of action, i.e. when speaking the speaker puts himself under a certain obligation. Promising, undertaking, vowing are the most typical ones.The illocutionary point of expressives is to express the psychological state specified in the utterance. The speaker is expressing his feelings or attitudes towards an existing state of affairs, e.g. apologizing, thanking, congratulating.The last class “declarations” has the characteristic that the successful performance of an act of this type brings about the correspondence between what is said and reality.7. What is indirect language use? How is it explained in the light of speech act theory?答：When someone is not saying I an explicit and straightforward manner what he means to say, rather he is trying to put across his message in an implicit, roundabout way, we can say he is using indirect language.Explanation (略) (见教材p.84-85)8. What are the four maxims of the CP? Try to give your own examples to show how floutingthese maxims gives rise to conversational implicature?答：Cooperative Principle, abbreviated as CP. It goes as follows:Make your conversational contribution such as required at the stage at which it occurs by the accepted purpose or direction of the talk exchange in which you are engaged.To be more specific, there are four maxims under this general principle:(1) The maxim of quantity①Make your contribution as informative as required (for the current purpose of theexchange).②Do not make your contribution more informative than is required.(2) The maxim of quality①Do not say what you believe to be false.②Do not say that for which you lack adequate evidence.(3) The maxim of relationBe relevant.(4) The maxim of manner①Avoid obscurity of expression.②Avoid ambiguity.③Be brief (avoid unnecessary prolixity).④Be orderly.9. What is pragmatic failure? Try to find instances of pragmatic failure in the English usedby Chinese learners of English.答：The technical term for breakdowns in the course of communication is pragmatic failure.Pragmatic failure occurs when the speaker fails to use language effectively to achieve a specific communication purpose, or when the hearer fails to recognize the intention or the illocutionary force of the speaker’s utterance in the context of communication.Instances (略) (见教材p.89)。

证券投资学-06章简明教程PPT课件

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证券投资学第6章 8
证券投资学第6章 9
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证券投资学第6章 2
典型的投资者：在不确定性决策的环境中，不但希望投资收益最大化，还要求投资风险最小化，其决策是实现两个相互制约目标之间的某种平衡。
马柯维茨的思路：分别用期望收益率和收益率的方差来衡量
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型来阐述如何全盘考虑上述两个目标，从而进行投资决策。结论：投资者应该通过同时购买多种证券而不是一种证券，进行分散化投资。
证券投资学第6章 5
第一节
单个资产的收益和风险
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生化简明教程章节习题集第六章

第六章生物氧化与氧化磷酸化一、练习题目(一)名词解释1．生物氧化2．高能磷酸化合物3．电子传递链4．磷酸原5．电子传递抑制剂6．氧化磷酸化作用7．底物水平磷酸化作用8．解偶联作用9．磷氧比(P／O)10．穿梭作用(二)问答题1．何谓生物氧化?它有何特点?其作用的关键是什么?生物氧化的方式?2．举例说明高能化合物可分为哪几种键型。

3．影响ATP水解时自由能释放的重要因素是什么?4．电子传递链上有哪几类电子传递体?各作用如何?5．如何证明电子传递链各组分的排列顺序和方向?6．写出电子传递链的排列顺序。

7．在电子传递链上可拆离成哪几个电子传递复合物?各复合物作用是什么?8．电子传递抑制剂主要有哪几种?其毒害作用机理是什么?9．谷氨酸十丙酮酸α酮戊二酸十丙氨酸：已知25℃时丙氨酸合成的Keq为1．107，试计算该反应的ΔG0’值。

10．计算下列各反应的ΔG0’值：(1)ATP+GDP→GTP+ADP；(2)3—磷酸甘油酸+ATP→1.3—二磷酸甘油酸+ADP；(3)NADH氧化生成水11．在真核生物中，指出下列各反应中P/O比的理论值：(1)3—磷酸甘油醛→1，3—二磷酸甘油酸；(2)琥珀酸—延胡索酸；(3)异柠檬酸→α→酮戊二酸；(4) α—酮戊二酸→琥珀酸12．真核生物细胞质内形成的NADH+H+，当其电子传递给氧时，为什么只产生2ATP?13．关于氧化磷酸化机理有哪几种主要学说，其中目前较为公认的是哪一种，其主要内容是什么?其实验证明是什么?14．在真核生物中，根据化学历程计算lmol葡萄糖彻底氧化能产生多少ATP?(三)填空题1．自由能的单位是______________。

当△G>0时，则反应____________自发进行，此反应称为__________反应，其Keq__________1。

2．标准自由能变化与标准氧化还原电势变化的关系为____________。

3．在标准条件下，一般将水解时释放以上自由能的化合物称为高能化合物。

电工学简明教程完整版

PLC 的程序有系统程序和用户程序两种。系统程序用户不能修改。
用户程序是用户根据控制要求，利用 PLC 厂家提供的程序编制语言和指令编写的应用程序。
6.2.1 可编程控制器的编程语言
PLC 的编程语言以梯形图语言和指令语句表语言最为常用，并且两者之间一一对应，可以相互转换。
1．梯形图
梯形图是一种从继电接触器控制电路图演变而来的图形语言。它是借助于继电器的动合触点、动断触点、线圈以及串联与并联等术语和符号，根据控制要求连接而成的表示 PLC 输入和输出之间逻辑关系的图形。
6．外部设备接口
外部设备接口将外部设备与主机相连，以完成相应操作。
第6章可编程控制器
6.1.2 可编程控制器的工作方式
PLC 采用“顺序扫描、不断循环”的方式进行工作。其工作过程分为输入取样、程序执行和输出刷新三个阶段，并进行周期循环。示意图如下：
输
输
入
入
端
接
子
口
输入状态寄存
读
程序执行
CPU 是 PLC 的核心，主要用来运行用户程序，监控输入/输出接口状态。
系统程序存储器 PLC 内部存储器用户程序及数据存储器
系统程序存储器，主要存放系统管理和监控程序及对用户程序作编译处理的程序。用户不得更改。
用户程序及数据存储器，主要存放用户编制的应用程序输入输出变量及各种暂存数据和中间结果。

第6章可编程控制器 PLC 硬件系统结构图
编程器
打印机
计算机磁带机扫描仪
外
部
PL主C机
设
备
存储器
接口
系统用户数程序程序据
按钮

动画速写第6章简明教程PPT课件

二、比例任何事物都有其正常的比例，而在创意速写的画面中我们可以任意改变这些比例，从而产生意想不到的视觉效果。例如常规的写实速写训练在构图上有严格的要求，要通过控制画面的上下、左右空间来控制画面的平衡。在创意速写的绘画过程中则可以与之相反，在构图上可采用求险、求满、求空、求偏、求局部等方式。这样，在画面构图的选择上可获得全新的效果（如图6-10、图611所示）。
7.1.2创意速写的创造性思维创意速写强调“创意”，创意是设计过程的本质，也是最重要的生产力，而创意的产生和表现则依赖于创造性思维的发散。创造性思维是思维的高级形式，是指人们在创新意识驱动下，通过各种思维方式对头脑中的信息和认知进行新的整合和加工，从而形成新意念、新思想、新观点的思维过程。也就是说，凡是打破传统模式而形成的思维活动，就可以称之为创造性思维。创造性思维是一种突破常规的思维方式，它在很大程度上是以感性直觉为基础而进行一种思维活动。因此，创意速写不能机械地摹写对象，而应主动地从多角度、多视点对物象进行观察、分析和表现，力求在真实表现对象的基础上创造出新的形象。从某种程度上说，设计是把不可能变成可能的创作过成，在速写训练的基础阶段，学生应有意识地培养创造性思维和表现力。如果速写训练仅仅止步于对客观物象形态进行观察和临摹，那么思维只能停留在经验的表层，从而阻碍创造力的发挥（如图6-1所示）。
图6-2 创意速写（学生作业）
二、简化简化是指将自然物象简化，以主观的态度进行取舍，去掉非本质的细节，从而达到造型的单纯化、意味化和抽象化。一般来说，简化的手法有两种，一是从意象形态出发，用简单的形象表现复杂的物体和情绪；二是从几何形态出发，将物象概括为球形、圆锥形、圆柱形、方形等几何形，反映出物象的本质；三是从心灵意识出发，排除自然物象琐碎的表象，进而创作出最直观的作品（如图6-3所示）。

材料力学简明教程(景荣春)课后答案第六章

( ) wA
= − q0l 4 30EI
↓
，θB
= q0l3 24EI
（顺）
讨论：请读者按右手坐标系求 wA ，θB 并与以上解答比较。
(c)
(c1)
解图(c1)
( ) ∑ M B = 0 ， FC
= − Me l
↓
CA 段
M
=
−
Me l
x1
⎜⎛ 0 ⎝
≤
x1
<
l 2
⎟⎞ ⎠
AB 段
M
=
−
Me l
l 2
≤
x2
≤
l ⎟⎞ ⎠
Ew1′′
=
3 8
qlx1
−
1 2
qx12
EIw1′
=
3 16
qlx12
−
1 6
qx13
+
C1
EIw1
=
1 16
qlx13
−
1 24
qx14
+
C1 x1
+
D1
EIw′2′
=
3 8
qlx2
−
ql 2
⎜⎛ ⎝
x2
−
l ⎟⎞ 4⎠
EIw′2
=
3 16
qlx22
−
ql 4
⎜⎛ ⎝
x2
24
EIw′(l) = 0 ，− q l 3 + 3Al 2 + 2Bl = 0
6
解式（a），（b）得
A = ql ， B = − ql 2
12
24
即挠曲线方程为
EIw = − q x4 + ql x3 − ql 2 x2 24 12 24

理论力学简明教程(第二版)课后答案

第零章数学准备一泰勒展开式1 二项式的展开()()()()()m 23m m-1m m-1m-2f x 1x 1mx+x x 23=+=+++！！2 一般函数的展开()()()()()()()()230000000f x f x f xf x f x x-x x-x x-x 123!''''''=++++！！特别:00x =时,()()()()()23f 0f 0f 0f x f 0123!x x x ''''''=++++！！3 二元函数的展开(x=y=0处)()()00f f f x y f 0x+y x y ⎛⎫∂∂=++ ⎪∂∂⎝⎭，22222000221f f f x 2xy+y 2x x y y ⎛⎫∂∂∂++ ⎪ ⎪∂∂∂∂⎝⎭！评注：以上方法多用于近似处理与平衡态处的非线性问题向线性问题的转化。

在理论力问题的简单处理中，一般只需近似到三阶以内。

二常微分方程1 一阶非齐次常微分方程： ()()x x y+P y=Q通解：()()()P x dx P x dx y e c Q x e dx -⎛⎫⎰⎰=+ ⎪⎝⎭⎰注：()()(),P x dx P x dx Q x e dx ⎰±⎰⎰积分时不带任意常数，()x Q 可为常数。

2 一个特殊二阶微分方程2y A y B =-+ 通解：()02B y=K cos Ax+Aθ+注：0,K θ为由初始条件决定的常量 3 二阶非齐次常微分方程 ()x y ay by f ++=通解：*y y y =+；y 为对应齐次方程的特解，*y 为非齐次方程的一个特解。

非齐次方程的一个特解（1）对应齐次方程0y ay by ++=设x y e λ=得特征方程2a b 0λλ++=。

解出特解为1λ，2λ。

*若12R λλ≠∈则1x 1y e λ=，2x 2y e λ=；12x x 12y c e c e λλ=+*若12R λλ=∈则1x 1y e λ=，1x 2y xe λ=； 1x 12y e (c xc )λ=+*若12i λαβ=±则x 1y e cos x αβ=，x 2y e sin x αβ=；x 12y e (c cos x c sin x)αββ=+（2）若()2000x f a x b x c =++为二次多项式*b 0≠时，可设*2y Ax Bx C =++ *b 0≠时，可设*32y Ax Bx Cx D =+++注：以上1c ,2c ,A,B,C,D 均为常数，由初始条件决定。

弹性力学简明教程第四版徐芝纶第六章

解题的具体步骤单元的划分计算成果的整理
第十节
计算实例
第十一节应用变分原理导出有限单元法的基本方程例题习题的提示与答案教学参考资料
第六章用有限单元法解平面问题
FEM
第六章
用有限单元法解平面问题
概述
1.有限元法(Finite Element Method，简称 FEM) —是弹力的一种近似解法。首先将连续体变换为离散化结构，然后再应用结力方法或变分法进行求解。 2. FEM的特点（1）具有通用性和灵活性。
e
e
e
第六章用有限单元法解平面问题
结力法求解
归纳起来，FEM分析的主要内容：
1. 将连续体变换为离散化结构。 2.应用结构力学方法求解离散化结构, 对单元进行分析：求出（1）单元的位移模式，（2）单元的应变和应力列阵，（3）单元的结点力列阵，（4）单元的结点荷载列阵。整体分析：建立结点平衡方程组，求解各结点的位移。
5 3Leabharlann 5 3u u0 y, v v0 x,
可见刚体位移项在式（a）中均已反映。
第六章用有限单元法解平面问题
收敛性条件
对式（a）求应变，得
x 2 , y 6 , xy 3 5 , 可见常量应变也已反映。
（3）位移模式应尽可能反映位移的连续性。即应尽可能反映原连续体的位移连续性。在三角形单元内部，位移为连续；在两单元边界ij 上，和δ 之间均为线 δi j 性变化，也为连续。
FEM是取结点位移 δi 为基本未知数的。但其中每一个单元仍是连续体，所以按弹力公式求应变、应力时，必须首先解决：如何由单元的结点位移 δe (δi δ j δm T 来求出单元的 T 位移函数d (u( x, y) v( x, y) 。应用插值公式，可由δ e 求出位移d。这个插值公式表示了单元中位移的分布形式，因此称为位移模式。

简明英语语言学教程第二版第6章答案

Chapter 6 PRAGMATICS1. What does pragmatics study? How does it differ from traditional semantics?答：Generally speaking, pragmatics is the study of meaning in the context. It studies meaning in a dynamic way and as a process. In order to have a successful communication, the speaker and hearer must take the context into their consideration so as to effect the right meaning and intention. The development and establishment pragmatics in 1960s and 1970s resulted mainly from the expansion of the study semantics. However, it is different from the traditional semantics. The major difference between them lies in that pragmatics studies meaning in a dynamic way, while semantics studies meaning in a static way. Pragmatics takes context into consideration while semantics does not. Pragmatics takes care of the aspect of meaning that is not accounted for by semantics.2. Why is the notion of context essential in the pragmatic study of linguistic communication? 答：The notion of context is essential to the pragmatic study of language. It is generally considered as constituted by the knowledge shared by the speaker and the hearer. Various continents of shared knowledge have been identified, e.g. knowledge of the language they use, knowledge of what has been said before, knowledge about the world in general, knowledge about the specific situation in which linguistic communication is taking place, and knowledge about each other. Context determines the speaker's use of language and also the heater's interpretation of what is said to him. Without such knowledge, linguistic communication would not be possible, and without considering such knowledge, linguistic communication cannot be satisfactorily accounted for in a pragmatic sense. Look at the following sentences:(1) How did it go?(2) It is cold in hem.(3) It was a hot Christmas day so we went down to the beach in the afternoon and had agood time swimming and surfing.Sentence (1) might be used in a conversation between two students talking about an examination, or two surgeons talking about an operation, or in some other contexts; (2) might be said by the speaker to ask the hearer to turn on the heater, or leave the place, or to put on more clothes, or to apologize for the poor condition of the room, depending on the situation of context; (3) makes sense only ii the hearer has the knowledge that Christmas falls in summer in the southern hemisphere.3. How are sentence meaning and utterance meaning related, and how do they differ?答： A sentence is a grammatical concept, and the meaning of a sentence is often studied as the abstract, intrinsic property of the sentence itself in terms of predication. But if we think of a sentence as what people actually utter in the course of communication, it becomes an utterance, and it should be considered in the situation in which it is actually uttered (or used). So it is impossible to tell if “The dog is barking” is a sentence or an utterance. It can be either. It all depends on how we look at it and how we are going to analyze it. If we take it as a grammatical unit and consider it as a self-contained unit in isolation from context, then we are treating it as a sentence. If we take it as something a speaker utters in a certain situation with a certain purpose, then we are treating it as an utterance.Therefore, while the meaning of a sentence is abstract, and decontextualized, that of anutterance is concrete, and context-dependent. The meaning of an utterance is based on sentence meaning; it is the realization of the abstract meaning of a sentence in a real situation of communication, or simply in a context. Now, take the sentence "My bag is heavy" as an example. Semantic analysis of the meaning of the sentence results in the one-place predication BAG (BEING HEA VY). Then a pragmatic analysis of the utterance meaning of the .sentence varies with the context in which it is uttered. For example, it could be uttered by a speaker as a straightforward statement, telling the hearer that his bag is heavy. It could also be intended by the speaker as an indirect, polite request, asking the hearer to help him carry the bag. Another possibility is that the speaker is declining someone's request for help. All these are possible interpretations of the same utterance “M y bag is heavy”. How it is to be underst ood depends on the context in which it is uttered and the purpose for which the speaker utters it.While most utterances take the form of grammatically complete sentences, some utterances do not, and some cannot even be restored to complete sentences.4. Try to think of contexts in which the following sentences can be used for other purposes than just stating facts:a) The room is messy.b) Oh, it is raining!c) The music of the movie is good.d) You have been keeping my notes for a whole week now.答：a) A father entered his son’s room and found it is very messy. Then when he said, “The room is messy,” he was blaming his son for not tidying it up.b) A son asked his father to play with him outside. So when the father said, “Oh, it’s raining”,he meant they couldn’t play outside.c) Two persons just watched a movie and had a discussion of it. One person sai d, “The story ofthe movie is very moving”, so wh en the other person sai d, “The music of the movie is good”, he me ant he didn't think the story of the movie was good.d) A person wanted his notes bac k, so when he said, “you ha ve been keeping my notes for awhole wee k now”, he was demanding the return of his notes.5. According to Austin, what are the three acts a person is possibly performing while making an utterance. Give an example.答：According to Austin's new model, a speaker might be performing three acts simultaneously when speaking: locutionary act, illocutionary act, and perlocutionary act.A locutionary act is the act of uttering words, phrases, clauses. It is the act of conveying literal meaning by means of syntax, lexicon and phonology. An illocutionary act is the act of expressing the speaker’s intention; it is the act performed in saying something. A perlocutionary act is the act performed by or resulting from saying something; it is the consequence of, or the change brought about by the utterance; it is the act performed by saying something. Let's look at an example:You have left the door wide open.The locutionary act performed by the speaker is his utterance of the wo rds “you”, “have”, “door”, “open”, etc. thus expressing what the words literally mean.The illocutionary act performed by the speaker is that by making such an utterance he has expressed his intention of speaking, i.e. asking someone to close the door, or making acomplaint, depending on the context.The perlocutionary act refers to the effect of the utterance. If the hearer gets the speaker's message and sees that the speaker means to tell him to close the door, the speaker has successfully brought about the change in the real world he has intended to; then the perlocutionary act is successfully performed.6. What are the five types of illocutionary speech acts Searle has specified? What is theillocutionary point of each type?答：(1) representatives: stating or describing, saying what the speaker believes to be true(2) directives: trying to get the hearer to do something(3) commissives: committing the speaker himself to some future course of action(4) expressives: expressing feelings or attitude towards an existing(5) declarations: bringing about immediate changes by saying somethingThe illocutionary point of the representatives is to commit the speaker to something's being the case, to the truth of what has been said, in other words, when performing an illocutionary act of representative, the speaker is making a statement or giving a description which he himself believes to be true. Stating, believing, sweating, hypothesizing are among the most typical of the representatives.Directives ate attempts by the speaker to get the hearer to do some- thing. Inviting, suggesting, requesting, advising, wanting, threatening and ordering are all specific instances of this class.Commissives are those illocutionary acts whose point is to commit the speaker to some future course of action, i.e. when speaking the speaker puts himself under a certain obligation. Promising, undertaking, vowing are the most typical ones.The illocutionary point of expressives is to express the psychological state specified in the utterance. The speaker is expressing his feelings or attitudes towards an existing state of affairs, e.g. apologizing, thanking, congratulating.The last class “declarations” has the characteristic that the successful performance of an act of this type brings about the correspondence between what is said and reality.7. What is indirect language use? How is it explained in the light of speech act theory?答：When someone is not saying I an explicit and straightforward manner what he means to say, rather he is trying to put across his message in an implicit, roundabout way, we can say he is using indirect language.Explanation (略) (见教材p.84-85)8. What are the four maxims of the CP? Try to give your own examples to show how floutingthese maxims gives rise to conversational implicature?答：Cooperative Principle, abbreviated as CP. It goes as follows:Make your conversational contribution such as required at the stage at which it occurs by the accepted purpose or direction of the talk exchange in which you are engaged.To be more specific, there are four maxims under this general principle:(1) The maxim of quantity①Make your contribution as informative as required (for the current purpose of theexchange).②Do not make your contribution more informative than is required.(2) The maxim of quality①Do not say what you believe to be false.②Do not say that for which you lack adequate evidence.(3) The maxim of relationBe relevant.(4) The maxim of manner①Avoid obscurity of expression.②Avoid ambiguity.③Be brief (avoid unnecessary prolixity).④Be orderly.9. What is pragmatic failure? Try to find instances of pragmatic failure in the English usedby Chinese learners of English.答：The technical term for breakdowns in the course of communication is pragmatic failure.Pragmatic failure occurs when the speaker fails to use language effectively to achieve a specific communication purpose, or when the hearer fails to recognize the intention or the illocutionary force of the speaker’s utterance in the context of communication.Instances (略) (见教材p.89)。

模拟电子技术简明教程第三版第六章放大电路中的反馈

Io Aii I i
反馈系数： Fii I f R3 Io R3 RF
21
第二节
负反馈的四种组态和反馈的一般表达式
四种反馈类型的比较
输出信号反馈信号电压串联式电压并联式电流串联式电流并联式放大倍数反馈系数
o U
f U
Auu
Uo U i
Uf Fuu Uo
负反馈的四种组态和反馈的一般表达式
Rb + C1
Rc1
Re2
Rc3
+VCC C2
U be U i U f
电流串联负反馈
Re3 If Io RF Re3 Re1
-
+
Ui
-
U be + U f Re1 减小
+
VT1 +
VT2 +
Io If
VT3 +
+
Rc2
RF
Uo
-
Re3
断开VT1发射极不计IE对Uf的贡献
反馈回路F
X X 放大： Ao o' 反馈： F f X X i o 'X X 叠加： X i i f
5
第一节
反馈的基本概念
二、反馈的分类
1. 正反馈和负反馈
正反馈：使放大电路净输入量增大的反馈。负反馈：使放大电路净输入量减小的反馈。判断方法：瞬时极性法。
二、减小非线性失真和抑制干扰
A
无反馈大小
小
大大
A
大
小
小
F
引入负反馈
负反馈减小了波形失真同样道理，负反馈可抑制放大电路内部噪声。

简明英语测试教程第三版课后答案第六章课后题答案

简明英语测试教程第三版课后答案第六章课后题答案1、Allen is looking forward to _______ his American partner at the trade fair. [单选题] *A. meetB. meeting(正确答案)C. be meetingD. having meeting2、I do not have my own room,_____. [单选题] *A. neither does Tom(正确答案)B. neither has TomC. so does TomD. so has Tom3、I passed the test, I _____ it without your help. [单选题] *A.would not passB. wouldn't have passed(正确答案)C. didn't passD.had not passed4、I think _______ is nothing wrong with my car. [单选题] *A. thatB. hereC. there(正确答案)D. where5、Where have you _______ these days? [单选题] *A. been(正确答案)B. beC. isD. are6、I tell my mother not ______ me.（）[单选题] *A. worry aboutB. to worry about(正确答案)C. worry withD. to worry with7、73．（）about the man wearing sunglasses during night that he was determined to follow him．[单选题] *A. So curious the detective wasB.So curious was the detective(正确答案)C.How curious was the detectiveD.How curious the detective was8、What’s the point of going to school when I can’t do anything there? [单选题] *A. 时间B. 意义(正确答案)C. 方向D. 目标9、I hope to see you again _______. [单选题] *A. long long agoB. long beforeC. before long(正确答案)D. long10、Every means _____ but it's not so effective. [单选题] *A. have been triedB. has been tried(正确答案)C. have triedD. has tried11、—Is this Tony’s history book?—No, it isn’t ______.（）[单选题] *A. himB. his(正确答案)C. heD. himself12、65．There is a big sale on in the shop! Every-thing is ________ price. [单选题] * A．bigB．fullC．zeroD．half(正确答案)13、She works in a hospital. She is a(n) _______. [单选题] *A. managerB. engineerC. doctor(正确答案)D. patient14、She passed me in the street, but took no（）of me. [单选题] *Attention (正确答案)B. watchC. careD. notice15、I saw the boy _______?the classroom. [单选题] *A. enter intoB. enter(正确答案)C. to enter intoD. to enter16、( ). I’m _____ in that ______ film [单选题] *A. interesting interestedB. interested interesting(正确答案)C. interested interestedD. interesting interesting17、I am so excited to receive a _______ from my husband on my birthday. [单选题] *A. present(正确答案)B. percentC. parentD. peace18、76．AC Milan has confirmed that the England star David Beckham （）the team soon. [单选题] *A. has rejoinedB. was going to rejoinC. rejoinedD. is to rejoin(正确答案)19、—_____ are the Olympic Games held? —Every four years [单选题] *A. How longB. How often(正确答案)C. How soonD. How far20、54．—________?—Yes, please. I'd like some beef. [单选题] *A．What do you wantB．May I try it onC．Can I help you(正确答案)D．What else do you want21、—The weather in Shanghai is cool now, ______ it? —No, not exactly. （）[单选题] *A. doesn’tB. isC. isn’t(正确答案)D. does22、The house is well decorated _____ the disarrangement of a few photos. [单选题] *A. exceptB. besidesC. except for(正确答案)D. in addition to23、11．________ big furniture shop it is! [单选题] *A．HowB．WhatC．What a (正确答案)D．What an24、—Tony, it’s cold outside. ______ wear a jacket?—OK, mom.（）[单选题] *A. Why not(正确答案)B. Why don’tC. Why did youD. Why do you25、You can buy some pieces of bread from "_______". [单选题] *A. Bakery(正确答案)B. Travel AgencyC. LaundryD. Ticket Office26、I arrived _____ the city _____ 9:00 am _______ April [单选题] *A. at, in, atB. to, on, atC. in, or, atD. in, at, on(正确答案)27、25．—I ______ Beijing for a holiday.—________. [单选题] * A．will go；GoodbyeB．will go；Have a good time(正确答案)C．will go to；Have a good timeD．am going to；Have a fun28、I have seldom seen my father（）pleased with my progress as he is now. [单选题] *A. so(正确答案)B. veryC. tooD. rather29、I paid twenty yuan _______ the book. [单选题] *A. offB. backC. for(正确答案)D. with30、Although the story is written for children, it can be read by adult, _____. [单选题] *A. alsoB. eitherC. as wellD. too(正确答案)。

《普通物理学简明教程》(第2版) 下第六章 6-7

在实际熔解过程中，冰须从高于0°C的环境中吸热。冰增加的熵超过环境损失的熵，所以，若将系统和环境作为一个整体来看，在这过程中熵也是增加的。
如让这个过程反向进行，使水结成冰，将要向低于0°C 的环境放热。对于这样的系统，同样导致熵的增加。
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例题6-9 有一热容为C1、温度为T1的固体与热容为 C2、温度为T2的液体共置于一绝热容器内。
，总是由概率小的状态向概率大的状态进行，由包含
微观状态数目少的宏观状态向包含微观状态数目多的
宏观状态进行，这是热力学第二定律的统计意义。
如气体的绝热自由膨胀、热量从高温物体向低温物
体的自发传递、热功转换等过程。数学描述:
因系为统某S一b 状态Sa的≥熵k值l越n大W W，ba
所以 Wb Wa
它所对应的宏观状态
能量不仅有形式上的不同，而且还有质的差别。机械能和电磁能是可以被全部利用的有序能量，而内能是不能全部转化的无序能量。熵增加意味着系统能量中成为不可用能量的程度在增大，这叫做能量的退化。
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物质或能量转化问题的三条基本规律：
(1)物质守恒定律物质可以从一种形式转化为另一种形式，但它既不能产生，也不能消灭。
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*四、熵增和热寂
热寂：19世纪的一些物理学家，把热力学第二定律推广到整个宇宙，认为宇宙的熵将趋于极大，因此一切宏观的变化都将停止，宇宙将进入“一个永恒的死寂状态”，这就是热寂说。而现实的宇宙并没有达到热寂状态。有人认为热寂说把热力学第二定律推广到整个宇宙是不对的，因为宇宙是无限的，不是封闭的。现代宇宙学认为，目前的宇宙是处于不断膨胀的状态，对于一个膨胀的宇宙，其每一瞬时熵可能达到的极大值Sm是与时俱增的，实际上宇宙的熵值的增长, 将落后于Sm的增长，二者的差距越来越大。因此，宇宙的熵虽然在不断增大，但是它离平衡态却愈来愈远, 宇宙充满了由无序向有序的发展变化，呈现在我们面前的是一个丰富多彩、千差万别、生气勃勃的世界。

理论力学简明教程第六章答案

《证券投资学简明教程》 练习题及参考答案 第6章

物理化学简明教程习题答案

物理学简明教程 马文蔚等 高教出版社

简明英语语言学教程第二版第6章答案

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电工学简明教程完整版

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材料力学简明教程(景荣春)课后答案第六章

理论力学简明教程(第二版)课后答案

弹性力学简明教程 第四版 徐芝纶第六章

简明英语语言学教程第二版第6章答案

模拟电子技术简明教程第三版第六章放大电路中的反馈

简明英语测试教程第三版课后答案第六章课后题答案

《普通物理学简明教程》(第2版) 下 第六章 6-7

《证券投资学简明教程》练习题及参考答案第6章

物理学简明教程马文蔚等高教出版社

弹性力学简明教程第四版徐芝纶第六章

《普通物理学简明教程》(第2版) 下第六章 6-7