生物聚合物波谱学导论((英)琼斯(D.W.Jones)主编;江丕栋等译)思维导图
高分子导论
高分子化学：Polymer Chemistry,
• 通过化学合成或改性制备具有一定结构 的聚合物。主要研究聚合反应和高分子 化学反应的原理，过程及控制工艺条件。
1，高分子化合物的含义
• 许多原子以一定规律由共价键连接而组 成的分子量很大（104-107 g/mol）的 化合物。
1920年德国Staudinger首先提出现代高 分子的概念 Macromolecule, Polymer, High Polymer.Supramolecule: 超分子化合 物
Mw> Mη> Mn 用Mw或Mη来描述高分子的分子量更准确。
聚合物分子量分布指数（polydispersity）d= Mw/ Mn一般情况下d>1.5 （凝胶渗透色谱GPC 测 定）
单分散聚合物（monodisperse polymer）
Mw/Mn= M η/Mw= 1
• 举 例: 假设某一聚合物样品中，分子量为104 的M1分子有10 mol，分子量为105的M2分子有 5 mol，分子量为5*105的M3分子有5 mol, 则：
• 假设某一聚合物样品中所含聚合物分子 总数为n，总质量为w，其中，分子量为 Mi的分子有ni摩尔，所占分子总数的数 量分数为Ni，则Ni = ni/n，其质量为wi = niMi，其质量分数为Wi = wi/w， ∑ni = n, ∑wi = w, ∑Ni =1, ∑Wi =1。
数均分子 量按分子数统计平均，定义为聚合物中分子量 为Mi的分子的数量分数Ni与其分子量Mi乘 积的总和, 以 Mn 表示。
1998 • “Principles of Polymerization”G. Odian, 4rdEd.
John Wiley & Sons, 2004 • “Polymer Chemistry, an introduction”M.P. Stevens,
材料导论_北京化工大学中国大学mooc课后章节答案期末考试题库2023年
材料导论_北京化工大学中国大学mooc课后章节答案期末考试题库2023年1.MSE involves the generation and application of knowledge relating _____ totheir _______ and uses, having interdisciplinary and multidisciplinarycharacteristics.答案:Composition, structure, and processing of materials, properties2. A concept that place recycling at the beginning or design stage of thematerials cycle to ensure that waste going into municipal landfills will beminimized.答案:Design for disassembly3.If there are components in the center of each face in addition to those at thecorners of the cube, then the unit cell is called.答案:Face Centered Cubic4.Which one typically has the largest thermal expansion?答案:Polymer5.Metals are good conductors of both_______________.答案:Electricity and heat6.The fiber reinforcement becomes more effective, when ____答案:the fiber length is larger than critical fiber length7.The hollow parts such as tanks can be produced by _______答案:Filament Winding8.Which one is the expression for the rule of mixture?答案:Ec=EmVm+EfVf9.________ experiment is carried out outside of the organism, usually in a testtube or petri dish.答案:In vitro10.Nanomaterials are generally defined as any particulate material with the sizeof __ nm in at least one dimension.答案:1-10011.The properties of crosslinked hydrogels depend on .答案:Crosslinking Density12.The cost of a finished piece includes _______.答案:The cost of raw materialsAny expense incurred during fabrication13.What are the characters of stiff materials?答案:High Bonding Energy within the MaterialHigh Elastic Modulus14.How to increase transition temperature range of brittle to ductile?答案:Increase grain sizeAdding certain elementsStrain hardening15.What are the factors influencing creep resistance of polycrystalline materials?答案:TemperatureStructures like Grain Types16.Sintering is a heat treatment applied to a powder compact toimpart _____________答案:IntegrityStrength17.LLDPE and LDPE have lower density than HDPE, because ______.答案:LLDPE and LDPE contains branchesHDPE is primarily a linear polymerThe formation of side branches will reduce the packing efficiency18. is an elastomer having physical cross-links in the “network” structure.答案:SISSBS19.Ceramics have the excellent properties as following:答案:Corrosion resistanceExtreme hardness20.Which can be selected as matrix materials for composites?答案:PolymerCeramicMetal21.The reinforcing effect of carbon black in tires is the result of the ______ of itsparticles.答案:Uniform DistributionGood adhesive bonding with the rubber molecules22.The additives used in polymer nanocomposites can be _____答案:NanofibersNanotubesNanoparticlesNanoclays23.Why fiberglass-reinforced composites are used extensively.答案:These composites have relatively high specific strengths.Glass fibers are very inexpensive to produce.They are chemically inert in a wide variety of environments.24.Materials science involves investigating the relationships that exist betweenthe structures and properties of materials.答案:正确25.Tensile strength can be estimated from the hardness reading.答案:正确26.Natural rubber usually is much stronger and harder than vulcanized rubber.答案:错误27.The modulus of crystalline polymers is higher than the modulus of anamorphous polymer答案:正确28.Viscoelasticity is a combination of elasticity and viscosity答案:正确29.Ceramics are crystalline compounds that combine metallic and nonmetallicelements.答案:正确30.Traditional ceramic materials include clays, refractories, glass, cement andabrasives.答案:正确31. A composite is composed of two (or more) individual materials, which comefrom metals, ceramics, and polymers.答案:正确32.Carbon-carbon composite is based on carbon fibers答案:正确33.Surface erosion could be characterized as zero order release.答案:正确。
谱学导论第二版习题答案
谱学导论第二版习题答案谱学导论第二版习题答案谱学导论是一门研究光谱学原理和应用的学科。
通过对物质与光的相互作用进行研究，谱学导论可以揭示物质的组成、结构和性质。
谱学导论第二版是该学科的经典教材，其中的习题对于学生来说是非常重要的学习资源。
下面将对该教材中的一些习题进行解答，帮助读者更好地理解光谱学的基本原理。
习题一：什么是光谱学？它的应用领域有哪些？光谱学是研究物质与光的相互作用的学科。
它通过分析物质与光的相互作用过程中产生的光信号，来研究物质的组成、结构和性质。
光谱学的应用领域非常广泛，包括但不限于以下几个方面：1. 化学分析：通过分析物质的光谱特征，可以确定物质的组成和浓度，用于化学分析和质量控制等领域。
2. 物质结构研究：通过分析物质的光谱数据，可以揭示物质的分子结构和化学键的性质，用于有机化学、无机化学等领域的研究。
3. 天文学研究：通过观测天体的光谱，可以了解宇宙中物质的组成和演化过程，揭示宇宙的奥秘。
4. 环境监测：通过分析环境中物质的光谱特征，可以监测和评估环境中的污染物，用于环境保护和治理。
习题二：什么是原子光谱？它的分类有哪些？原子光谱是研究原子与光的相互作用的光谱学分支。
原子光谱可以分为发射光谱和吸收光谱两类。
1. 发射光谱：当原子受到能量激发后，电子从高能级跃迁到低能级时，会辐射出特定波长的光。
这些特定波长的光可以通过光谱仪进行分析，得到原子的发射光谱。
发射光谱可以用于原子的定性和定量分析。
2. 吸收光谱：当原子受到外界光的照射时，电子会吸收与其能级差相等的能量，从基态跃迁到激发态。
吸收光谱是通过测量原子吸收光的强度和波长来研究原子的能级结构和物理性质的。
吸收光谱可以用于原子的定性和定量分析。
习题三：什么是分子光谱？它的分类有哪些？分子光谱是研究分子与光的相互作用的光谱学分支。
分子光谱可以分为振动光谱和旋转光谱两类。
1. 振动光谱：分子由于其振动和转动而具有一系列能级。
当分子受到外界光的照射时，分子的振动能级会发生跃迁，产生特定波长的光谱。
凝聚态物理导论00
From Complexity to Simplicity (continued) Each stage of reduction is marked by the appearance of quasistable particles which had been mistakenly identified as “elementary” particles. With each stage of reduction, the length scale drastically decreases, while the energy scale drastically increases (see Fig. 1).
(in Chinese),《凝聚态物理学新论》(上海科技出版社)
New systematics was thoroughly discussed and illustrated with various current topics in this field National Award of Science and Technology Progress, 1997, in China
Electromagnetic Force is Ubiquitous
the sole fundamental force responsible for various complicated phenomena in condensed matter physics
3. Historical Track of Scientific Development
A brief overview of condensed matter physics
• The Position of Condensed Matter Physics in Physics • From Solid State Physics to Condensed Matter Physics • The Theoretical Framework of Condensed Matter Physics
全套课件 聚合物物理学
❖可用来测分子量
（4）侧基 (side group)
由单体带入的与主链相接的基团
例：－(CH2－CH)－
聚苯乙烯中的苯环
CH3 ｜ －(CH2－C)－ ｜
C=O ｜
OCH3
聚甲基丙烯酸酯中的甲基和酯基 (C4H9)
（5）支链 branch
由聚合生成：结构与主链相同 与侧基的区分:侧基化学结构与主链不同
O
O
O
N
R
N
O
O
O
O NO O NO O NO
R
R
R
OO
OO
N
N
N
梯形聚合物示例
1.4.2 聚合物网络
简单 网络
互接 网络
互穿 网络
半互穿 网络
S S S
CH2-CH-CH-CH2 -CH2-CH=CH-CH2 -CH2-CH-CH-CH2
S S S S 互接网络示例：硫化橡胶 S S
CH2-CH-CH-CH2 -CH2-CH=CH-CH2 -CH2-CH-CH-CH2
1.6 平均分子量
分子量与聚合度
分子量：分子的质量 g/mol 聚合度：分子链中结构单元的个数
500 (CH2 CH)n
聚合
(CH2 CH)500
乙烯 + 丁烯-1 共聚
-CH2-CH3 -CH2-CH3
-CH2-
-CH2-
CH2-
-CH2-CH3
-CH2-
POE
乙烯 + 辛烯-1 共聚
-CH2-
-CH2 -CH2 -CH2 -CH2 -CH2 -CH3 -CH2 -CH2 -CH2 -CH2 -CH2 -CH3
CH2-
第三课：表面电子结构
For z << L: If we integrate ρ-(z)- ρ0- from z=0 to z=, we find:
拓展到三维情况
有表面存在情况下的动量空间
Assuming the electrons are bounded in z-direction by impenetrable potential at z=0 and z=L, and free to move in xy-direction:
一维线性链模型
考虑由N个原子组成的线性链，原子间距为a：
a 1 2 a 3 a 5 a 6
……..
N
体系的周期性势场为VL(r)为各格点原子势场Va(r-na)之和：
VL (r ) Va (r na)
n 1 N
其中孤立原子的薛定谔方程为：
[2 Va (r ) Ea ] (r ) 0
Ves(r)
下一次课
Remarks
• The jellium model description of a metal surface neglects the details of the electron-ion interaction and emphasizes the nature of the smooth surface barrier. • The nearly free electron model emphasizes the lattice aspects of the problem and simplifies the form of the surface barrier.
波函数在表面处的连续性
E 3 2
Shockley state Vg<0
《谱学导论》各章习题+参考答案
第一章 习 题1.127I 35Cl 的转动常数是0.1142 cm -1，计算ICl 的键长。
2. 12C 16O 2的转动常数是0.39021 cm -1。
计算分子的键长。
3. 已知14N 16O 的键长是115 pm 。
计算该分子23←=J 跃迁的纯转动光谱的频率。
4. 计算12C 16O 分子12←=J 纯转动跃迁的频率。
已知分子的键长是112.81 pm 。
5. 已知35Cl 19F 转动常数是1.033 cm -1，计算分子的转动惯量和键长。
6. 下列那些分子有纯转动光谱？H 2、HCl 、CH 4、CH 3Cl 。
7. 下列那些分子有红外吸收光谱？O 2、CCl 3-CCl 3、HF 、CO 2。
8.35Cl 2的振动基频是564.9 cm -1，计算分子化学键的力常数。
9. 79Br 81Br 振动基频是323.2 cm -1。
计算分子化学键的力常数。
10. 拉曼光谱的入射频率是20487 cm -1，计算O 2分子02←=J 的Stokes 线的波数。
11. 拉曼光谱的入射频率是20623 cm -1，计算N 2分子24←=J 的Stokes 线的波数。
12. 实验测定得到H 2和D 2在入射波长为488.0 nm 的激光照射下的大拉曼位移分别是612.1 nm 和571.4 nm 。
计算他们的力常数并说明力常数变化不大的原因。
13. 对下列点群，写出给定直积表示的特征标，并约化成不可约表示的直和：（1） C 2h 点群：g u B A ⊗（2） C 4v 点群：E B A ⊗⊗2214. 求积分⎰ΓΓτψψd F j i ˆ不等于零时，F ˆ应该属于那些不可约表示？ （1）D 3点群：2A i =Γ，E j =Γ （2） C 2v 点群：2A i =Γ，2B j =Γ15. 画出乙炔分子所有可能的简正振动方式，并指出哪些是有红外活性的，哪些没有？16. 写出下列分子的基态和第一激发态的电子谱项，并根据选律判断，哪些跃迁是允许的，哪些是禁阻的？（1）H 2；（2）LiH ；（3）N 217. HCl 分子的光谱学解离能e D =5.33eV ，7.2989~=νcm -1，νχ~e=52.05 cm -1。
生命科学导论知到章节答案智慧树2023年同济大学
生命科学导论知到章节测试答案智慧树2023年最新同济大学第一章测试1.生物信息学与转化医学是课程的重要内容之一。
（）参考答案:对第二章测试1.生命的特征和本质包括（）。
参考答案:新陈代谢;生长;运动;能量传递2.生命现象是（）这些量综合运动和传递的表现。
参考答案:能量;物质;信息3.细胞命运决定本质上是基因的程序性表达和调控机制。
（）参考答案:对4.2005年，由日本科学家Shinya Yamanaka发现的体细胞重编程技术可使得体细胞转变成为诱导多能干细胞。
（）参考答案:错5.经典的Yamanaka因子包括哪些？（）参考答案:c-Myc;Klf4;Sox2;Oct46.以下关于体细胞基因组的说法错误的是（）。
参考答案:同一个人不同体细胞的基因表达水平是相同的7.人胚胎干细胞走向临床应用的主要障碍包括（）。
参考答案:伦理限制;免疫排斥8.John Gurdon通过将羊分化细胞中的细胞核，利用核移植的方式引入到卵母细胞质中，继而发育获得了成年子代。
（）参考答案:错9.美国干细胞生物学家James Thomson在2008年建立了世界上第一个人类胚胎干细胞系。
（）参考答案:错10.英国发育生物学家John Gurdon首次证明了细胞基因组是可以逆转变化的。
（）参考答案:对第三章测试1.成体小鼠骨髓中，100万个血细胞里大概包含多少造血干细胞（）。
参考答案:70~802.造血干细胞最早由哪一类细胞转化而来（）。
参考答案:生血内皮细胞3.检测造血干细胞功能的体内移植实验包括（）。
参考答案:限制性稀释移植实验;竞争性移植实验4.造血干细胞的定义是（）。
参考答案:自我更新;分化为下游所有类型的血液细胞5.以下哪个特性能够体现骨髓间充质干细胞的自我更新能力（）。
参考答案:克隆集落的形成6.人的造血干细胞和小鼠的造血干细胞细胞表面标记物不同，但是体内重建血液系统地能力是相同的。
（）参考答案:对7.造血干细胞的表面标记物在任何情况下都是不变的。
Chapter1-introduction
材料物理导论Fundamentals of Materials Science andEngineering (MSE)孟凡研Monday: Jiaoxue Building 101 (9:55-11:30) Wednesday: Jiaoxue Building 101 (9:55-11:30)Email: meng7707@理化楼 2351Materials Science and Engineering:An Introduction, 6th editionWilliam D. Callister Jr., John Wiley & Sons, Inc. Reference材料科学基础，余永宁主编，高等教育出版社 Assessment method40% from attendance, quizs , homework, case study60% from final examTextbook2Course objective…Introduce fundamental concepts in MSE…You will learn about…• Material structure• How structure dictates properties • How processing can change structure3 scheduleWEEKTOPICCHAPTERS1 General introduction; atomic bonding 1,2 1 Crystalline structure; crystallographic direction; plane, miller-index3 2 Miller-bravas-index, interstice, 3 2 Imperfection; vacancies; interstitials, impurities, solid solution, edge, dislocation4 3 Grain boundary, staking fault, diffusion4, 5 3 Mechanical properties6 4Dislocation motion, plastic deformation, slip system, twinning74scheduleWEEK TOPICCHAPTERS4 Strengthening mechanism:refining grains;7 5Failure85Phase diagram86 Fe-C alloy phase diagram 9 6 Phase transformation in metals 107 Application and Processing of Metal Alloys11 7 Review 1-108Final examination5 6北京科技大学课程中心平台7 Chapter 1Introduction89MetalGlassPlasticsBeverage containerIntroductionHistorical perspective Stage 1: materials that exist naturally, such as stone, wood, clay, and skin.Stage 3: materials that are modified by heat treatment and addition of other substances, such as steel and AlCu (bronze). Stage 2: materials that are produced by humans, such as pottery and metals.Stage 4: advanced materials that are made based on knowledge of processing - structure - property - performance relationship, such as metals, plastics, glasses, and fibers.10IntroductionMaterials Science and Engineering•Materials science involves investigation of relationship between structures and properties of materials•Materials engineering involves designing and engineering the structure of materials to produce desired properties11IntroductionWhat is structure?On an atomic level, structure encompasses the organization of atoms or molecules relative to one another.Subatomic structure is arrangement of electrons within each individual atoms, and their interactions with nuclei 12IntroductionIn brief, the structure of a material usually relates to the arrangement of its internal components.Microscopic : larger structural realm is subject to direct observation using some type of microscope.Macroscopic : structural elements may be viewed with the naked eye.Structure has many dimensions13 IntroductionWhat is properties?•Property is a trait in terms of the kind and magnitude of response to a specific imposed stimulus.• 6 groups mechanical, electrical, thermal, magnetic, optical, deteriorative14IntroductionprocessingperformanceWhat determines structure ?What does property affect ?15Introductionfour basic elementsSynthesis-Processing Composition-StructurepropertiesPerformance/Application16IntroductionThe material selection process1. Pick Application (performance) Determine required properties (6)2. Properties3. MaterialIdentify candidate materialMaterial: structure, compositionIdentify required processingProcessing: changes structure and overall shape Ex: casting, sintering, vapor deposition, doping , forming, joining, annealing17IntroductionStructure, processing, properties184wt%C compositionexample: hardness vs. structure of steelProperties dependon structureProcessing can change structureexample: structure vs. cooling rate of steelIntroduction19 Introduction 20Introduction21 Introduction 22Introduction23 IntroductionWhy study MSE?How does one select “proper” materials ?How can one know the selection criteria?An engineer has to select materials at various stages of his/her engineering24IntroductionHow does one select ‘proper’ materials? •Fit the in-service condition•resist deterioration•Economical•Recycling, without pollutionPerformance ApplicationDurability, reliability, environmental compliance costecomaterial25A reasonable compromise may be necessary! Introduction four basic elementsSynthesis-Processing Composition-StructurepropertiesPerformance/Application26Introductionknowledgeable in materials science and engineeringHow can one know the selection criteria?five basic elements propertiescompositionstructuretheory, modeling,material andtechnology designsynthesis/processing performanceenvironment (T, pressure, ambient, medium) 27IntroductionBasic classification of Materials (3) contain large numbers of nonlocalized electrons, good conductors of electricity and heat, not transparent to light, lustrous appearance, strong yet deformable. CeramicsCompounds between metallic and nonmetallic elements, oxides, nitrides, and carbides, insulative to electricity and heat, resistant to high T and harsh environments, hard but brittle.PolymersOrganic compounds that are chemically based on C, H, and other nonmetallic elements, with large molecular structure. Low density, extremely flexible. steelglass, cement, clay mineralsrubber, plasticMetals28IntroductionOther groups of important engineering materials (3) composites semiconductors biomaterials Combination of materials, designed to display a combination of the bestcharacteristics of each of the componentmaterialsfiberglass: glass fibers (strength) embedded in polymer (flexibility)electrical properties sensitive to smallamount of impurity, key elements ofintegrated circuitry.silicon, carbonEmpolyed in components implanted intothe human body for replacement ofdiseased or damaged body parts, notproduce toxic substances, compatible with body tissuesmetal, ceramics, polymers, composites, semiconductors29IntroductionAdvanced Material•electronic equipment (VCR, CD players, LCDs) •computers•fiber-optic systems•spacecraft •aircraft •military rocketryUtilized in high-tech applications expensivecomplicate to make 30IntroductionShape memory alloys (SMA): shape changes in response to temperature changes;Piezoelectric ceramics: shape changes in response to an applied electrical field (or voltage);Magnetostrictive materials : shape changes in response to an applied magnetic field;Electrorheological/magnetorheological fluids: viscosity changes in response to changes in electric or magnetic field.Future materials （1）“Smart Materials”: sense and respond to changes in environment.31IntroductionFuture materials （2） NanotechnologyThe general procedure has been to begin by studying large and complex structures, and then to investigate the fundamental building blocks of these structures that are smaller and simpler.32Introduction“Top down” Science“Bottom -up” approachIt has been possible to manipulate and move atoms and molecules to form new structures and, thus, design new materials that are built from simple atomic level constituents. This ability to carefully arrange atoms provides opportunities to develop mechanical, electrical, magnetic, and other properties that are not otherwise possible.CoalGraphiteDiamonds33 Introduction34Is it possibleto handle atoms ? Yes !NanotechnologyIntroduction35•What have been done… Micro-chipsMicro-motorsNanotechnologyIntroductionEngr Mater: 0136Dreams…Nano-pumpNano-bearingsNano-armNano-chips ?NanotechnologyIntroduction37 •Reading: Richard P. Feynman’ s talk: “There's Plenty of Room at the Bottom”at /nanotech/feynman.htmlAnother very fun book to read: 'Surely You're Joking, Mr. Feynman!‘NanotechnologyIntroductionFuture materials （3）BiotechnologyApply mechanical/physical/chemical principles to biotechnology38Introduction39 BiotechnologyWhy can gecko walk on the wall without difficulties? Introduction40BiotechnologyWhy can gecko walk on the wall without difficulties?Introduction41 BiotechnologyWhy can water skipper walk on the water?Introduction42BiotechnologyShoes for mountain climbing, adhensive tape, adhensive paper, recycling.They are masters majored in applied physics! Nanostructure!Van Der Waals ForceIntroduction43 壁虎脚底的粘着力究竟是怎样产生的呢？美国加利福尼亚大学伯克利分校的科学家罗伯特·福尔等人经过研究发现看上去不起眼的壁虎，居然是自然界数一数二的“应用物理大师”。
Introduction to VLSI Physical Design
Chapter1: Introduction to VLSI PhysicalDesignSadiq M.Sait&Habib YoussefKing Fahd University of Petroleum&MineralsCollege of Computer Sciences&EngineeringDepartment of Computer EngineeringSeptember2003IntroductionPresent day VLSI technology permits us to build systems with hundreds of thousands of transistors on a single chip.For example:•the Intel80286microprocessor has over105transistors,•the80386has275,000transistors,•the80486has approximately106,transistors.•The RISC processor from National SemiconductorNS32SF641has over106transistors.•The Pentium processor has over3×106transistors.ICs of this complexity would not have been possible without computer programs which automate most design tasks.•Designing a VLSI chip with the help of computerprograms is known as CAD.•Design Automation(DA),on the other hand,refers toentirely computerized design process with no or verylittle human intervention.•CAD and DA research has a long history of over threedecades.As technology has changed from SSI to VLSI,•The demand for DA has escalated.•The types of DA tools have multiplied due to changing needs.•There has been a radical change in design issues.•Due to sustained research by a number of groups,sophisticated tools are available for designing ICs,and we are briskly moving towards complete DA.Physical Design•Physical design is the process of generating thefinallayout for the circuit.•This is a very complex task.•In order to reduce the complexity several intermediatelevels of abstractions are introduced.•More and more details are introduced as the designprogresses from highest to lowest levels of abstractions.•Typical levels of abstractions together with theircorresponding design steps are illustrated in Figure.Levels of abstractionCAD subproblem level Behavioral/Architectural Register transfer/logic Cell/maskGeneric CAD toolsBehavioral modeling andSimulation toolTools for partitioning,placement, routing, etc.Functional and logic minimization,logic fitting and simulation tools IdeaArchitectural designLogical designPhysical designFabricationNew chipFigure1:Levels of abstraction&corresponding de-sign stepLogical&Architectural Design •As indicated the design is taken from specs to fabricationstep by step with the help of CAD tools.•Architectural design of a chip is carried out by experthuman engineers.•Decisions made at this stage affect the cost andperformance of the design significantly.•Once the system architecture is defined,it is necessary tocarry out two things:(a)Detailed logic design of individual circuit modules.(b)Derive the control signals necessary to activate and deactivate thecircuit modules.•Thefirst step is known as data path design.•The second step is called control path design.ExampleIt is required to design an 8-bit adder.The two operands are stored in two 8-bit shift registers A and B .At the end of the addition operation,the sum must be stored in A .The contents of B must not be destroyed.The design must be as economical as possible in terms of hardware.MUX AMUX B Q DS A S M AB M Bin D FA C out S B M M A S B Read A Read B R C R D Add load B load A Clock Start in C (a)(b)AS Figure 2:Organization of a serial adder:(a)Data Path•There are numerous ways to design the above circuit,•Since it is specified that the hardware cost must beminimum,it is perhaps best to design a serial adder.•The organization of such an adder is shown infigure.•The relevant control signals are tabulated below.S A Shift the register A right by one bitS B Shift the register B right by one bitM A Control multiplexer AM B Control multiplexer BR D Reset the Dflip-flopR C Reset the counterST ART A control input,which&commences the addition•The control algorithm for adding A and B is given below. forever dowhile(START=0)skip;Reset the Dflip-flop and the counter;Set M A and M B to0;repeatShift registers A and B rightby one;counter=counter+1;until counter=8;High-level Synthesis•Several observations can be made by studying theexample of the serial-adder.•First,note that designing a circuit involves a trade-offbetween cost,performance,and testability.•The serial adder is cheap in terms of hardware,but slowin performance.•It is also more difficult to test the serial adder,since it is asequential circuit.•The parallel8-bit CLA is likely to be fastest in terms ofperformance,but costliest in hardware.•All the different ways that we can think of to build an 8-bit adder constitute what is known as the design space (at that particular level of abstraction).•Each method of implementation is called a point in the design space.•There are advantages and disadvantages associated with each design point.•When we try optimizing the hardware cost,we usually lose out on performance,and vice versa.•There are many more design aspects,such as power dissipation,fault tolerance,ease of design,and ease of making changes to the design.•A circuit specification may pose constraints on one or more aspects of thefinal design.•For example,when the specification says that the circuit operate at a minimum of15MHz,we have a constraint on the timing performance.•Given a specification,the objective is to arrive at a design which meets all the constraints posed by the specification, and optimizes on one or more of the design aspects.•This problem is also known as hardware synthesis.•Computer programs have been developed for data path synthesis as well as control path synthesis.•The automatic generation of data path and control path is known as high-level synthesis.Logic Design•The data path and control path will have componentssuch as arithmetic/logic units,shift registers,multiplexers,buffers,etc.•Further design steps depend on the following factors.(1)How is the circuit to be implemented,on a PCB or asa VLSI chip?(2)Are all the components available as off-the-shelf ICscircuits or as predesigned modules?•If the circuit must be implemented on a PCB usingoff-the-shelf components,then the next stage is to selectthe components.Logic Design-contd•Following this,the ICs are placed on boards and thenecessary interconnections are established.•A similar procedure may be used in case the circuit isimplemented on a VLSI.•These modules are also known as macro-cells.•The cells must be placed on the layout surface and wiredtogether using metal and polysilicon(poly)interconnections.Physical Design•Physical design of a circuit is the phase that precedes thefabrication of a circuit.•In most general terms it refers to all synthesis stepssucceeding logic design and preceding fabrication.•These include all or some of the following steps:1.Circuit Partitioning.2.Floorplanning and Channel Definition.3.Circuit Placement.4.Global Routing.5.Channel Ordering.6.Detailed routing of power and ground nets.7.Channel and Switchbox Routing.Physical Design-contd•The performance of the circuit,its area,its yield,and itsreliability depend on the layout.•Long wires and vias affect the performance and area ofthe circuit.•The area of a circuit also has a direct influence on theyield of the manufacturing process.Layout Styles•These approaches differ mainly in the structuralconstraints they impose on the layout elements and thelayout surface.•They belong to two general classes:(a)The full-custom layout approach.(b)The semi-custom approaches.•Current layout styles are:1.Full-custom;2.Gate-array design style;3.Standard-cell design style;4.Macro-cell(Building block layout);5.PLA(Programmable Logic Array);and6.FPGA(Field Programmable Gate-Array)layout.Full-Custom Layout•Full-custom layout refers to manual layout design.•Full-custom design is a time-consuming and difficult task.•Gives full control to the artwork designer inplacing/interconnecting.•A high degree of optimization in both the area andperformance is possible.•Takes several man-months to layout a chip.•Therefore is used only for circuits that are mass produced(microprocessors).•For circuits which will be reproduced in millions,it isimportant to optimize on the area as well as performance.•Designers productivity is increased with the help of aGate-Array Layout•A gate-array(MPGAs)consists of transistorsprefabricated on a wafer in the form of a regular2-Darray.•Initially the transistors in an array are not connected toone another.•In order to realize a circuit on a gate-array,metalconnections must be placed using the usual process ofmasking(personalizing).•Short fabrication time,(only four processing steps).•Low cost of production due to yield.•Limited wiring space,therefore present difficulties to automatic layout generator.•A special case of the gate-array architecture is when routing channels are very narrow,or virtually absent.is called Sea of Gates(Channel-less Gate-Arrays).•A typical gate-array cell personalized as a two-input NAND gate is shown in Figure.nMOS pMOS GND Vdd nMOS pMOSGND Vdd A BB Aout (a)(b)Figure 3:(a)Example of a basic cell in a gate array (b)Cell personalized as a two-input NAND gateVertical channelHorizontal channelGatePad Switch boxFigure 4:A gate array floor plan•A standard cell,known also as a polycell,is a logic that performs a standard function.•Examples of standard-cells are two-input NAND gate, two-input XOR gate,Dflip-flop,two-input multiplexer.•A cell library is a collection of information pertaining to standard-cells.•The relevant information about a cell consists of its name, functionality,pin structure,and a layout for the cell in a particular technology such as2µm CMOS.•Cells in the same library have standardized layouts,i.e., all cells are constrained to have the same height.•Description of an inverter logic module named i1s. Focus only on the profile,termlist,andcell begin i1s generic=i1primitive=INVarea=928.0transistors=2function="q=INV((a))"logfunction=invertprofile top(-1,57)(15,57);profile bot(-1,-1)(15,-1);termlista{(1-4,-1)(1-4,57)}pintype=inputrise\_delay=0.35rise\_fan=5.18fall\_delay=0.28fall\_fan=3.85loads=0.051unateness=INV;q{(9-12,-1)(9-12,57)}pintype=output;siglist GND Vdd a q;translist m0a GND q length=2000width=7000 type=n m1a Vdd q length=2000width=13000type=p;caplist c0Vdd GND 2.000f c1q GND 5.000f c2Vdd a 2.000f c3a GND11.000f; cell end i1sLayout-Inverter Standard Cell Figure5:Layout of a standard-cell i1sCell-Based Design•Similar to designing a circuit using SSI and MSIcomponents.•Selection is now from a cell-library,and components areplaced in silicon instead of PCB.•Advantage:Designs can be completed rapidly.•The Layout program will only be concerned with:(1)the location of each cell;and(2)interconnection of the cells.•Placement and routing is again simplified using astandardfloorplan(see Figure).•The disadvantage in relation to gate-array is that all thefabrication steps are necessary to manufacture.Cell-Based Design-contdWasted spaceFeedthrough cell Routing channelPadABFigure 6:Floorplan of a standard-cell layoutMacro-cell Layout•No restrictions as in gate-array and standard-cell design.•The cells can no longer be placed in a row-basedfloorplan.•This design style is called macro-cell design style,orbuilding-block design style.Macro-cell Layout-contd12345 67213456(a)(b)7Figure7:(a)Cells of varying heights and widths placed in a row-basedfloorplan(b)A more compactMacro-cell Layout-contd Advantages:•Cells of significant complexity are permitted in the library(registers, ALUs,etc).•Building-block layout(BBL)comes closest to full-custom layout.•Like standard-cell layout style,all the processing steps are required to manufacture a BBL chip.Disadvantages:•It is much more difficult to design layout programs for the BBL design style.•This is because there is no standardfloorplan to adhere to.As a result, the routing channels are not predefined either.•Floorplanning and channel definition are additional steps required in a BBL layout system.FPGA layout•Similar to an MPGA,an FPGA also consists of a2-Darray of logic blocks.•Each logic block(CLB)can be programmed toimplement any logic function of its inputs.•In addition to this,the channels or switchboxes containinterconnection resources.•They contain programmable switches that serve toconnect the logic blocks to the wire segments,or one wiresegment to another.•Furthermore,I/O pads are also programmable to be eitherinput or output pads.Logic blocks InterconnectPadsFigure8:Diagram of a typical FPGA•The main design steps when using FPGAs to implement digital circuits are:1.Technology Mapping,2.Placement,3.Routing,andfinally,4.Generating the bit patterns.•The main disadvantages are their lower speed of operations and lower gate density.•FPGAs are most ideally suited for prototyping applications,and implementation of random logic using PALs.Difficulties in Physical Design •Physical design is a complex optimization problem,involving several objective functions.•Some of these objectives are conflicting.•It is therefore customary to adopt a stepwise approach and subdivide the problem(e.g.,Circuit Partitioning,Floorplanning,etc.,).•All of the aforementioned subproblems are constrained optimization problems.•Unfortunately these layout subproblems(even simplified versions)are NP-Hard.•Therefore,instead of optimal enumerative techniques,heuristics are used.•Solution quality of heuristics is determined using artificial inputs whose optimal solutions are known or using test inputs comprising of realcircuits,called benchmarks,(MCNC,ISCAS).Terminology and Definitions•A cell.•A macro-cell.•The aspect ratio of a cell.•Logic module,or module,refers to macro or standard cells.•A module interfaces to other modules through pins.•A signal net,or simply net,is a collection of pins.•A netlist description is,as the name suggests,a list of all the nets in the circuit.•A graph is an abstract representation.•The connectivity information can be represented in the form of an n×n matrix C.Full-AdderA B C AND[1]AND[2]OR3[1]3AND[ ]ZFigure9:Logic diagram of’full-adder carry’circuitAND[1]AND[2]AND[3]1 42 5 7 83 6ABCOR3[1]ZFigure 10:The connectivity graph for the full-adder carry circuit12345678100010100200011000300001100411001110501110110610111010700011101800000010Figure11:The connectivity matrix for the full-adder carry circuit•Manhattan distance between the two pins located at coordinates (x 1,y 1)and (x 2,y 2),is given by d 12=|x 1−x 2|+|y 1−y 2|(1)AB (5,12)C (10,7)A (5,2)5,7B C(a)(b)Figure 12:(a)A minimum spanning tree (b)Steiner•In this session we introduced the basic concepts of VLSI physical design and Design Automation.•In order to automate the layout procedure,it is common to impose restrictions on the layout architecture.•Several layout architectures are popular.•In order to reduce the complexity the layout process is broken into a sequence of physical design phases.•The important design phases were presented.•Each of these phases amounts to solving a combinatorial optimization problem.•Table below assesses and compares several aspects of the various layout styles.Comparison of Layout styles.The number in parentheses indicates a rank to grade the layout style in comparison to others in the same category.Design Appl Design Fab Cost PerformanceStyle time EffortHighF-Custom volume High(4)High(2)High(4)High(4)Gate-array ASICs Low(2)Low(1)Low(2)Low(4)Stan-cell ASICs Low(3)High(2)Low(3)High(1)Macro-cell General High(1)High(2)Low(3)High(2)FPGA ASICs Low(1)Nil Low(1)Low(1)。
聚合物材料介绍书籍
聚合物材料介绍书籍
以下是有关聚合物材料介绍的书籍：
1. 《聚合物科学与工程导论》：该书详细介绍了聚合物化学、物理、力学和工程等方面的基本概念和知识，是聚合物树脂领域的入门教材。
2. 《聚合物化学和物理》：本书从分子结构、物理性质和化学反应等多个方面介绍了聚合物化学和物理的基础知识，深入浅出地讲解了聚合物的各种性质和应用。
3. 《高分子材料科学与工程》：该书系统地介绍了聚合物材料的制备、性质、结构和物理化学特性。
4. 《聚合物复合材料》：本书为高分子材料科学与工程本科以上的专业教材。
聚合物复合材料是一门内容广阔、与其他许多学科交叉渗透、互相关联的综合性学科。
本书主要讲解以聚合物为基体，与其他增强材料和填充材料复合而成的多组分、多相体系，具有优异力学性能。
此外，还可以查阅一些国内外知名大学的教材，例如：清华大学出版社出版的《高分子化学与物理》、北京大学出版社出版的《高分子科学导论》等。
这些书籍都有较为系统的介绍和阐述，有助于更好地了解聚合物材料。
改变世界的物理学_哈尔滨工业大学中国大学mooc课后章节答案期末考试题库2023年
改变世界的物理学_哈尔滨工业大学中国大学mooc课后章节答案期末考试题库2023年1.晶体三极管中有几个PN结？参考答案:22.在光纤通信中，下列哪一个激光器得到广泛应用？参考答案:砷化镓激光器3.生物学为物理学启示了（）定律参考答案:能量守恒4.下列哪个铁块的熵较小（）参考答案:所有电子自旋排列都是指向一个方向5.薛定谔的贡献，不仅仅在于引入物理学的概念来解释生命，更深远的意义是他开创了用（）的理论、方法和实验手段去研究生物学的先河。
参考答案:物理学_化学6.继人类基因组计划后又一个庞大计划，人类肝脏（），汇集全球16个国家和地区80多个研究室数千位科学家共同攻关，全面解读肝脏的奥秘。
参考答案:蛋白质计划7.薛定谔提出把探测物质结构的X射线衍射技术用到对生命物质的有机结构研究，将可使生物学从定性描述推向（）研究。
参考答案:定量8.相对而言，熵对下列哪种学科影响较小（）参考答案:心理学9.在光子计算机中，和电子计算机中“电子”功能类似的粒子是（）。
参考答案:光子10.材料在压力作用下产生电极化的现象称为（）参考答案:压电效应11.如今，物理学新概念、新技术催生了（）、量子生物学等学科，使生物大分子晶体结构、生物控制论等的研究范围和水平不断加宽加深。
参考答案:生物物理学12.当用X射线照射生命体系时，发现引起了遗传的突变。
这说明，生命以（）规律为基础。
参考答案:量子13.10个经典比特能同时存储（）个10位二进制数。
参考答案:114.强子（参与强相互作用的粒子，质子、中子属于强子）由（）组成。
参考答案:夸克15.从最大到最小排列这三种射线穿透纸张的能力参考答案:射线，射线，射线，16.应用于变压器中的磁性材料为（）。
参考答案:软磁材料17.在量子力学里，当几个粒子在彼此相互作用后，各个粒子所拥有的特性综合成为整体性质，无法单独描述各个粒子的性质，只能描述整体系统的性质，则称这现象为（）。
参考答案:量子纠缠18.x射线的波长范围是（）参考答案:0.0110纳米范围19.激光按输出方式又可分为（）参考答案:连续激光器_脉冲激光器20.全息成像是利用（）的原理将携带信息的光波以干涉图的形式记录下来。
量子物理基础鲁维
这时正值英国科学促进会在牛津开会。戴维森随里查森参加了会议。 在1926 年8月10日的会议上，他听到了著名的德国物理学家玻恩（M.Born） 讲到，戴维森和康斯曼从金属表面反射的实验有可能是德布罗意波动理论 所预言的电子衍射的证据。
液体的原子排列及其分子结构，对研究材料的应力分布和电阻，有 重要作用。
一、1921年，戴维森和助手康斯曼（C.H.Kunsman ）在用电子束轰击镍靶 的实验中偶然发现，镍靶上发射的“二次电子”竟有少数具有与轰击镍靶 的一次电子相同的能量，显然是在金属反射时发生了弹性碰撞，他们特别 注意到“二次电子”的角度分布有两个极大值，不是平滑的曲线。他们仿 照卢瑟福α散射实验试图用原子核对电子的静电作用力解释这一曲线。显 然，他们没有领悟到这是一种衍射现象。
汤姆孙用磁场将电子束偏向一方，发现整个图像平移，保留原来的 花样。由此肯定是带电粒子的射线，而不是X射线。 G.P.汤姆孙在他的正式论文中宣布：他得到的电子衍射图形与X射线
“粉末法”所得图形非常相似。这些图形的大小与德布罗意波动力 学理论预计的结果在5％的范围内相符。
（一）中华民族在人类 历史上曾经几度辉煌
1932
86
2003
7
王永志
1932
71
地球环境科学家 航空技术专家
2004
空缺
8
叶笃正
1916
பைடு நூலகம்89
世界气象学家
2005
9
吴孟超
1922
83
世界肝脏外科专家
10
2013PhysRevLett.107.137401Optically Controllable Photonic Structures with Zero Absorption
Optically Controllable Photonic Structures with Zero AbsorptionChris O’Brien*and Olga KocharovskayaDepartment of Physics and Astronomy and Institute for Quantum Studies,Texas A&M University,College Station,Texas77843-4242,USA(Received27May2011;revised manuscript received11August2011;published21September2011) We show the possibility to periodically modulate the refractive index in a homogeneous resonant atomic medium in space or/and time while simultaneously keeping vanishing absorption or gain.Such modulation is based on periodic resonant enhancement of the refractive index,controlled by an external opticalfield,and opens the way to produce coherently controllable photonic structures.We suggest the possible implementation of the proposed scheme in rare-earth doped crystals with excited state absorption.DOI:10.1103/PhysRevLett.107.137401PACS numbers:78.20.Ci,42.50.Gy,42.65.AnOne,two,or three-dimensional periodic heterostructures made of two dielectric materials with different refractive indices,such as distributed Bragg reflectors(DBRs),holey fibers,or photonic crystalsfind many applications,includ-ing reflective coatings,distributed feedback lasers,and optical cavities.Different technologies such as photoli-thography,etching,drilling,and self-assembling are used for construction of such structures.We suggest a method to produce transparent photonic structures in a homogeneous resonant atomic media,such as dielectrics with homogeneously distributed impurities, atomic,or molecular gases,simply by illuminating these materials with standing waves of a laserfield.Such opti-cally produced photonic structures could easily be con-trolled(including switching on or off,changing amplitude and period of modulation)and would be highly selective in frequency,naturally limited by the width of the optical resonance.Refractive index(RI)is strongly enhanced near atomic resonances.However,that enhancement is accompanied by enhancement of ly,when the maximal contribution from the atomic resonance to the RI is reached,the contribution to the absorption is on the same order which prevents the usage of obtained RI.There have been several proposals on how to resonantly enhance the refractive index while at the same time eliminating reso-nant absorption.One approach is based on interference effects in multilevel atomic systems driven by coherent resonantfields[1–5].Another suggestion is to compensate absorption with resonant gain from an inverted transition [6].Such a situation could be realized either in a mixture of two two-level atomic species,or in a single atomic species possessing simultaneously both noninverted and inverted transitions with slightly shifted frequencies[7].Proof of principle experiments were done in hot Rb vapors in which enhancement of the refractive indexÁn$10À4was achieved under negligible absorption[8,9].An enhance-ment up to the valueÁn$10À2is expected with an increase of density to N¼6Â1016cmÀ3.The further increase of the refractive index in room-temperature gases is not feasible due collisional broadening becoming the dominant contribution to the linewidth.Much higher reso-nant additions to the background index are anticipated in transition element doped crystals due to the essentially higher density of the ions which does not in general result in proportional line broadening[7,10,11].In all of these proposals the RI was uniform in space. Moreover,an enhancement of the RI with vanishing reso-nant absorption was achieved only at a particular detuning of the probefield from atomic resonance and was accom-panied by either absorption or gain at the neighboring detunings.Thus,none of those proposals were suitable for achieving spatial modulation of the refractive index with zero absorption.Our proposal is based on spatial modulation of the energy of a populated intermediate state in a nearly degenerate ladder configuration via the ac-Stark effect in a standing wavefield which results in a spatially dependent detuning leading to a periodic resonant increase and decrease of the refractive index in space while simul-taneously keeping transparency of the medium. Consider the interaction of a probefield with a medium of three level atoms in a ladder configuration such that the probefield interacts with both transitions as illustrated in the inset of Fig.1.The transition frequencies!21and!32 are close to each other so that the probefield with fre-quency!p interacts simultaneously with both transitions and for a weak probe Rabi frequency p( 21, 32the susceptibility is defined as the sum of the susceptibilities of two two-level transitions:¼3N38rad21ð 1À 2Þ21Ài 21þrad32ð 2À 3Þ32Ài 32:(1)Here N is the atomic density,the detunings are defined as 21¼!21À!p and 32¼!32À!p, is the probefield wavelength in the medium, rad ij is the radiative decay rate for the i to j transition, ij is the total decoherence rate,and i is the population in the i th energy level.We assume thatthe amplitudes of both transitions are matched but of opposite sign:rad 21ð 1À 2Þ¼À rad32ð 2À 3Þ;(2)which means that one of the two transitions is inverted.Letit be transition 2-1,i.e. 2À 1>0.We also assume the widths of the transitions are equal 21¼ 32and the probe field is tuned to two-photon resonance,i.e.!p ¼!31=2.Thus for arbitrary position of level 2the blue detuning of the probe field from one of two two-level transitions is equal to the red detuning from the other,i.e., 32¼À 21¼ ,leading to the remarkable property that gain at one transition and absorption at another one cancel each other while the real part of susceptibility is doubled.So,the susceptibility is purely real:¼3N 3 rad 21ð 1À 2Þ8 22 2þ 221:(3)It means that the probe field neither experiences absorptionnor gain independently of level 2’s energy,i.e.,for arbitrary values of .At the same time the resonant susceptibility varies from the minimum to the maximum value as is shifted from À to as shown in Fig.1.If the energy of the intermediate level is modulated in space along the direction of propagation of the probe field,the refractive index is also modulated.Such spatial modulation can be produced along the optical axis via the ac-Stark shift.A control laser field E s cos ð!s t Þapplied at the 0-2transition adjacent to the 1-2transition and far detuned from this transition Ás ¼!s À!20) 20would result in a split-ting of the intermediate state 2into two ac-Stark sublevels shifted in frequency by Àj s j 2=Ás and Ás þj s j 2=Ás ,respectively,where s is the associated Rabi frequency.The probe field is far out of resonance with the transitions from the second Stark sublevel from both level 1and level 3and,therefore its interaction with these transitions is neg-ligible while the first Stark sublevel is slightly shifted fromthe original level 2and strongly interacts with the probefield.In other words,the susceptibility at each transition (2-1or 2-3),which in general consists of two terms asso-ciated with the one-photon and two-photon resonances is reduced to the one-photon contribution and has the same form as given by Eq.(3),just with shifted transition frequencies.If the control field represents itself as a standing wave such that the Rabi frequency is a function of position inside the medium, s ðz Þ¼ s cos ðk s z Þ,then the ac-Stark shift of level 2is given by:ÁE ¼À@j s j 2s À@j s j 2scos ð2k s z Þ:(4)Thus it consists of a constant shift,j s j 2=2Ás ,and a sinu-soidal modulation,ðj s j 2=2Ás Þcos ð2k s z Þ.If the difference between the atomic transition frequencies !32À!21is chosen to be equal to Àj s j 2=Ás then the susceptibility is described by Eq.(3)with ¼ðj s j 2=2Ás Þcos ð4 z= s Þ(where s is the wavelength of the control field in the medium).Hence the refractive index will be modulated symmetrically with respect to its background value as shown in Fig.2.The spacial period s =2is defined by the wavelength,while the modulation depth Àj s j 2=Ás is defined by the Rabi frequency of the modulating field s .To provide the maximum amplitude of refractive index modulation the Rabi frequency of the control field should meet the condition 2s ¼2 Ás .With a strong enough index variation a transparent for a particular frequency 1-D photonic crystal can be created with properties that are optically controlled.Similarly a 2D or 3D photonic structure can be produced by application of 2or 3orthogonal modulating control fields.Even for index variations much smaller than the background RI the me-dium will behave as a distributed Bragg reflector if s ’ p specifically,when the wavelength mismatch is within the width of the Bragg band gap, s À p < s Án=ð n bg Þ.Since the medium remains transparent,many periods of spatial RI structures can be used as needed to achieve the required reflection coefficient.When the probe field is detuned from two-photon reso-nance with 1-3transition it will experience either gain or0.51.01.52.0zs1.00.50.51.0ReMaxFIG.2(color online).Real part of the susceptibility plotted as a function of position along the opticalaxis.21Re MaxFIG.1(color online).Real part of the susceptibility as a function of the level shift .Note that the imaginary part is identically zero.Inset:the energy level diagram for the corre-sponding three-level scheme.absorption.The question arises if such gain may result in the building up of a spontaneously amplified field empty-ing the inverted transition and limiting the propagation length of the probe field in the medium with periodic refractive index.Fortunately,this is not the case.Indeed,since the position of the intermediate level is periodically modulated in space,then a detuned probe field experiences periodically interchanging regions of gain and absorption suppressing the development of such an instability as can be seen in Fig.3.In fact averaging the absorption over a wavelength s shows that the medium is effectively trans-parent even when the probe field is detuned from resonance.The simple model of a ladder system previously dis-cussed assumed the existence of two transitions possessing equal linewidths,equal products of transition strength and population difference,and nearly degenerate (on the scale of the linewidth)frequencies.It is difficult if not impos-sible to meet these conditions in a real atomic system.However,it is possible to construct an effective ladder system whose upper transition has controllable parameters which could be optically tuned to satisfy these conditions.It can be accomplished by adding to the original simple ladder system along with the modulating control field E s coupled to an adjacent transition 0-2(as discussed above)a second control field E c coupling the excited state 3to an additional unpopulated level 4as shown in Fig.4.This second far-detuned control field (Ác ) rad 32, c where Ác ¼!43À!c and c is the control field Rabi fre-quency)is chosen to satisfy approximately the two-photon resonance condition:!c À!p ¼!42,forming together with the probe field a far-detuned lambda scheme.A strong far-detuned field results in an ac-Stark splitting of level 3and the response to the probe field consists of two terms representing one-photon (upper Stark sublevel)and two-photon (lower Stark sublevel)contributions in the same way as previously discussed.But now it is the two-photon contribution which plays a dominant role due to the two-photon resonance condition [7,12].As a result,the total five level system under the formu-lated above conditions is reduced to an effective three-level ladder system with the lower transition 1-2’’and the upper transition 2’’-3’.Its susceptibility takes the form:res¼3N 38 2rad 21p=ð2Àp Þ p þ 2s 2Ás þ Ài 21þ rad32=½ð2Àp Þð1þ2 Þ p À!32þ!21À 2s 2ÁsÀ þÁc ð1þ À 2ÞÀi ½ 42ð1À Þþ 32:(5)Where we assume incoherent pumping (not shown in Fig.4)which provides the necessary population inversion,represented by the pumping factor p ¼ð 2À 1Þ= 2.We also assume level 3is empty and introduce a control field parameter ¼j c j 2=Á2c ,as well as the one-photon detun-ing p ¼!21À!p .Now the parameters of the effective upper 2’’-3’and lower 1-2’’transitions defined by the control fields can easily be matched.We choose s ¼ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi2 21Ás p to provide the maximum range of refractive index modulation.Matching the line-width of 3’-2’’transition to that of 2’’-1defines the control field parameter :¼21À 4232À 42:(6)It implies a larger linewidth of the upper 2’’-3’transition as compared to the lower transition 1-2’’, 32> 21,and relatively slow decay of the coherence at the 4-2’’0.51.01.52.0zs0.50.5ImMaxFIG.3(color online).Imaginary part of the susceptibility for a probe field detuned from resonance by 21=20(solid line)and 21(dashed line)plotted as a function of position along the optical axis.FIG.4(color online).Energy level diagram for the 5-level system coupled with two control fields s and c leading in ac-Stark splitting of levels 2and 3and resulting in an effective ladder system 1-2’’-3’in the dressed state basis.transition: 42< 32, 21.Matching the amplitudes de-fines the pump parameter as:p ¼ rad 32rad 211þ2 :(7)We take the probe field to be resonant with the dressedtransition 2’’-1such that p ¼À 2s =2Ás .Then matching the frequencies of the transitions defines the required de-tuning of the control field Ác :Ác ¼!32À!21þ2 211þ À :(8)This implies that Ác will be on the same order as !32À!21.Since j c j ¼ffiffiffi p Ác and Ác %!32À!21,it is important to have 1-2and 2-3transitions with close frequencies in order to reduce the required control field intensity.Under the above conditions the susceptibility given by Eq.(5)takes the same form as in Eq.(3).Thus,it becomes possible to realize resonant modulation of the refractive index with zero absorption or gain in the realistic system.As an example we consider Er 3þ:YAG (n bg ¼1:82)where the 4I 9=2to 4I 15=2( rad 21¼45Hz )transition at 813.2nm (transition 2-1in Fig.4)has a closely matched excited state absorption transition (transition 2-3in Fig.4)from 4I 9=2to 4G 9=2( rad 32¼15Hz )with !32À!21¼20GH z [13,14].Coherent driving of the transition be-tween the next Stark level of the ground state and 4I 9=2level (transition 2-0in Fig.4)can be used for modulation of level 2position,while coherent driving of 4I 15=2and 4G 9=2can be used for matching of the parameters of the upper and lower transitions in the effective ladder system.Taking N ¼1:4Â1021cm À3and low enough temperature to limit phonon broadening we assume 32¼0:8GHz , 21¼0:3GHz ,and 42¼0:2GHz .Choosing pump pa-rameter p ¼0:035and the following parameters of the driving fields: s ¼2:45GHz ,Ás ¼10GHz , c ¼7:449GHz ,and Ác ¼17:893GHz ,we obtain 3.3%re-fractive index modulation with respect to background value (Á 0¼0:22)with a periodically modulated practi-cally vanishing absorption (max j 00j <0:0033)as shown in Fig.5.This result follows from the numerical analysis of the 5level system driven with two coherent fields,and is well approximated by the analytical formula in Eq.(5).We note that the chosen wavelength mismatch, s À p ¼1:45nm ,is much smaller than the width of the Bragg band gap, Án=ð n bg Þ,which in our case is equal to 8nm.Already a relatively thin medium with L ¼100 m (which corresponds to 245periods of modulation)provides a quite high reflection coefficient,R ¼0:99998.As the probe field is detuned from atomic resonance there will be absorption or gain which alternates on the scale of thewavelength as shown in Fig.3,resulting in zero net ab-sorption or gain.The produced DBR has a very narrow bandwidth of 0.6GHz (defined by the linewidth of atomic resonance)and may be used as a frequency selective reflector.In conclusion,we proposed a method to produce peri-odic modulation of the refractive index while keeping zero net absorption or gain.The method is based on spatial modulation of the energy of the populated intermediate state in an effective three-level system with matched tran-sition properties by an external strong control field via the ac-Stark effect.Possible implementation of this technique in Er 3þ:YAG is suggested,where a 3%modulation of the refractive index with vanishing absorption is possible.The proposed method may find useful applications for the creation of optically controllable photonic structures such as distributed Bragg reflectors,holey fibers,photonic crystals,etc.A major advantage of these structures as compared to traditional photonic structures is that they can be easily manipulated (including switching on or off,changing the amplitude and period of modulation)by varying the parameters of the optical control fields.This research was supported by NSF Grant No.0855688.*cobrien.physics@[1]M.O.Scully,Phys.Rev.Lett.67,1855(1991).[2]U.Rathe,M.Fleischhauer,S.Y .Zhu,T.W.Hansch,andM.O.Scully,Phys.Rev.A 47,4994(1993).[3]M.D.Lukin,S.F.Yelin,A.S.Zibrov,and M.O.Scully,Laser Phys.9,759(1999).[4]J.P.Dowling and C.M.Bowden,Phys.Rev.Lett.70,1421(1993).[5]M.Fleischhauer,C.H.Keitel,M.O.Scully,C.Su,B.T.Ulrich,and S.Y .Zhu,Phys.Rev.A 46,1468(1992).[6] D.D.Yavuz,Phys.Rev.Lett.95,223601(2005).z nm0.100.050.050.102004006008001000FIG.5(color online).Real (dashed line)and imaginary (solid line)part of the susceptibility as a function of distance along the optical axis for implementation of a optically controlled distrib-uted Bragg grating in Er 3þ:YAG with the parameters listed in the Letter.[7] C.O’Brien and O.Kocharovskaya,J.Mod.Opt.56,1933(2009).[8] A.S.Zibrov,M.D.Lukin,L.Hollberg,D.E.Nikonov,M.O.Scully,H.G.Robinson,and V.L.Velichansky,Phys.Rev.Lett.76,3935(1996).[9]N.A.Proite,B.E.Unks,J.T.Green,and D.D.Yavuz,Phys.Rev.Lett.101,147401(2008).[10]M.E.Crenshaw,C.M.Bowden,and M.O.Scully,J.Mod.Opt.50,2551(2003).[11] A.K.Rebane,C.W.Thiel,R.K.Mohan,and R.L.Cone,Bull.Russ.Acad.Sci.Phys.74,891(2010).[12]P.Anisimov and O.Kocharovskaya,J.Mod.Opt.55,3159(2008).[13] D.K.Sardar,C.C.Russell,J.B.Gruber,and T.H.Allik,J.Appl.Phys.97,123501(2005).[14]J.B.Gruber,J.R.Quagliano,M.F.Reid,F.S.Richardson,M.E.Hills,M.D.Seltzer,S.B.Stevens,C.A.Morrison, and T.H.Allik,Phys.Rev.B48,15561(1993).。
材料导论习题2有答案(英文版)
材料科学与工程导论1 Polymerization (聚合作用) is the process by which small molecules (分子) consisting of one unit or a few units are chemically joined to create these giant molecules. Those small molecule units are called______A) polymers B) monomers (单体)C) oligomers D)elastomers2 Choose the type of polymer material you might select for the following applications: an automobile bumper (保险杠), a mineral water bottle, and an insulating (绝热的) cable.A) For automobile bumper, the best choice of polymer is Natural Rubber.B) For mineral water bottle, the best choice of polymer is Low-Density（密度）Polyethylene (聚乙烯)C) For insulating cable, the best choice of polymer is polystyrene (聚苯乙烯).D) For mineral water bottle, the best choice of polymer is Polyethylene Terephthalate.3) In general, for a given type of thermoplastic (热塑性塑胶) the tensile (可延展的) strength, creep resistance impact toughness, wear resistance, and melting temperature all increase with______A) degree of polymerization B)density of branching C)tacticity D) crystallinity4) ABS, composed of acrylonitrile, butadiene, and styrene (苯乙烯), is one of the most common polymer materials. Styrene and acrylonitrile form a liner copolymer (异量分子聚合物) (SNA) that serves as a matrix. Styrene and butadiene also form a liner copolymer, BS rubber, which acts as the ______ material.A) fire retardant B) filler C) cross-linking D)plasticizer5) Epoxies （环氧树脂）are thermosetting polymers formed from molecules containing a tight C-O-C ring. During polymerization, the C-O-C rings are opened and the bonds are rearranged to join the molecules. If epoxy is used as an adhesive (粘剂) for a variety of applications, which kind of adhesives does it belong to?A) Chemically Reactive AdhesivesB) Evaporation or Diffusion AdhesivesC) Hot-Melt Adhesives D) Pressure-Sensitive Adhesives6) What area the major advantages associated with plastic compared to ceramics(陶瓷), glasses, and metallic materials?A) lightweight and corrosion(铁锈，腐蚀)-resistantB) high strength and high-temperature resistantC) high-temperature resistant and insulatingD) high stiffness and corrosion-resistant7) Which one is not a thermoset polymer?A) Polyethylene B) Natural Rubber C) Epoxy D) Phenolic8) Depending on the degree of cross-linking, the polyurethanes behave as thermosetting polymers, thermoplastics (热塑性塑胶), or elastomers. These polymers find application as fibers, coatings, and foams for furniture, mattress, and insulation. Why polyurethanes are versatile?A) for their polar repeat unit B) for their linear structureC) for their multi-functional monome r D) for their tactictity structure9) Liquid Crystalline(透明的) Polymers are polymers which behave as ______A) liquid B) thermoplastic C) thernoset D) oriented(取向) rods10) The glass temperature (Tg) is typically about ______ times the absolute melting temperature (Tm).A) 0.2 to 0.3 B) 0.5 to 0.7C) 0.8 to 1.0 D) 1.0 to 2.011) Most thermoplastic exhibit a non-Newtonian and visicoelastic behavior. The stress and train are not linearly related for most parts of the stress-strain curve. The viscoelastic behavior means when an external (外部的) force is applied to a thermoplastic _______ deformation occurs.A) only elastic B) both elastic and plastic (塑性)C) only plastic D) neither elastic nor plastic12) Compare the tensile strength of LDPE, HDPE, PVE, PP, and arrange them in sequence(顺序) from high strength to low tensile strength.A) LOPE>HDPE>PVE>PP B) LDPE>HDPE>PP>PVCC) PVC>PP>HDPE>LDPE D) PVC>HDPE>PP>LDPE13) Degree of polymerization is usually used to characterize ________A) cross-linking network B) thermosetting polymerC) polymer degradation D) thermoplastic polymer14) Silicones(硅) are important elastomer based on chains composed of silicon and oxygen atoms. The silicone rubbers provide high-temperature resistance, permitting use of the elastomer at temperature as high as _____℃. Low molecular weight silicones form liquids and are known as silicon oils.A) 100 B) 150 C) 200 D) 30015) There are a lot of thermoplastic processing methods, typical forming process includes: extrusion, blow molding, injection molding, thermoforming, calendaring and spinning. If we want to produce sping water bottles, which processing way is best choice?A) extrusion B) blow molding C) injection molding D) thermoforming16) The recycling of thermoplastics is relatively easy and practiced widely. Many of the everyday plastic products you encounter (bags, soda bottles, yogurt containers, etc.) have numbers stamped on them. For PRT products, the number is 1. For HDPE and LDPE, the numbers are_______, respectively. Other plastics are marked number 7,A) 3 and 4 B) 4 and 5 C) 2 and 4D) 2 and 317) The temperature above which a polymer burns, chars, or decompose. Which team is appropriately used in describing the remperature.A) Tg B) Td C) Tm D) HDT18) Which forming process is not a best choice for thermosetting polymers.A) Compression molding B)transfer moldingC) reaction injection D) spinning19) Elastomers are thermoplastics or lightly cross-linked thermosets that exhibit greater than _______ elastic deformation.A) 0.2% B ) 2% C) 20% D)200%20) Thermoplastic elastomers combine feature of both thermoplastics and elastomers.At high temperature, these polymers behave as ________ and are plastically into shapes, at how temperature, they behave as _________A) thermoplastics; elastomers B) thermoplastics; thermosetting polymersC) elastomers; thermoplastic D) elastomers; thermosetting polymers21 Define (a) a thermoplastic, (b) thermosetting plastics, (c) elastomers, and (d) thermoplastic elastomers.22) Explain what the following terms mean in polymer materials: decompositions temperate (Td), heat distortion temperature (HDT), glass temperature (Tg), and melting temperature (Tm).23) Typical forming processes for thermoplastic are schematicly shown blew, give each forming process a name and explain what kind of plastic products can be made by corresponding forming process.挤出吹塑延展喷涂…………24) The molecular weight of polymethyl methacrylate (PMMA) is 250,000g/mol. If all of the polymer chains are the same length.a) calculate the degree of polymerization, andb) the number of chains in 1g of the polymers.25) Explain why low-density polyethylene is good to make grocery bags, however, ultra-high molecular weight polyethylene must be used where strength and very high wear resistance is needed.26) How do the glass temperature of polyethylene, polypropylene, and polymethyl methacrylate compare? Explain their difference, based on the structure of the monomer?27) Give a materials example in your everyday life, explain the relationship of their structure and properties.bdada aacdb bcddb cbdda。
量子物理简介
p = mv = 2kg ⋅ m ⋅ s
−4
−1
∆p = 0.01% × p = 2 × 10 kg ⋅ m ⋅ s
位置的不确定量范围
−1
h 6.63 × 10 −34 −30 ∆x ≥ = m = 3.3 × 10 m −4 ∆p 2 × 10
青岛科技大学 大学物理讲义
的速率, 例4 一电子具有 200m ⋅ s -1 的速率 动量的不确 这也是足够精确的了) 范围为动量的 0.01% (这也是足够精确的了 , 则该 这也是足够精确的了 电子的位置不确定范围有多大? 电子的位置不确定范围有多大 解 电子的动量
青岛科技大学 大学物理讲义
在一束电子中， 例1 在一束电子中，电子的动能为 200 eV ，求 此电子的德布罗意波长 λ ？
1 2 解 v << c, Ek = m0v 2
−19
v=
2 Ek m0
2 × 200 × 1.6 × 10 −1 6 -1 v= m ⋅ s = 8.4 × 10 m ⋅ s −31 9.1× 10 h 6.63 ×10−34 = ∴λ = nm Q v << c −31 6 m0 v 9.1×10 × 8.4 ×10
青岛科技大学 大学物理讲义
四
薛定谔方程
..
薛定谔 (Erwin Schrodinger， 1887~1961)奥地利物理学家。1926 奥地利物理学家。 奥地利物理学家 年建立了以薛定谔方程为基础的波 动力学,并建立了量子力学的近似 动力学 并建立了量子力学的近似 方法 。 正如经典粒子的运动用牛顿公式描述一样， 正如经典粒子的运动用牛顿公式描述一样，微观粒子 的运动也必须用一个公式描述。 的运动也必须用一个公式描述。薛定谔提出了描述微 观粒子运动的方程，称为薛定谔方程。 观粒子运动的方程，称为薛定谔方程。 h 其中 h =
the_historical_development_of_quantum_theory__概述说明
the historical development of quantum theory 概述说明1. 引言1.1 概述量子理论是现代物理学中的一项重要学科，它描述了微观世界中的粒子行为和能量传递机制。
自从19世纪末以来，人们对物质本质的认识逐渐深入，并通过对光的波粒二象性以及原子内部结构的研究，揭开了一个个科学谜团。
量子力学的形成和发展使得我们对微观世界有了更准确和全面的认识，同时也带来了许多新颖而令人惊叹的应用领域。
1.2 文章结构本文将按照时间顺序，详细介绍量子理论的历史发展。
首先，我们将回顾古代人们对物质本质的认识，并探讨光的波粒二象性启示了何种突破。
接着我们将深入探索揭开原子内部结构之谜所进行的关键实验和发现。
随后，我们会详细介绍20世纪初波动力学和矩阵力学之间激烈竞争所导致的薛定谔方程产生以及其重要意义。
然后我们会讨论量子理论中的不确定性原理，揭示微观世界的局限性。
最后，我们将探讨量子力学在原子物理学、分子物理学、核物理学以及高能物理学等领域中的重要应用，并展望了量子信息科学和量子计算机的崛起。
1.3 目的本文旨在对量子理论的历史发展进行系列概述，并突出其在现代物理学中的重要性和广泛应用。
通过深入了解和思考过去的里程碑事件，我们可以更好地认识到科学研究发展的脉络，并有助于对未来量子理论发展和应用前景进行展望和思考。
2. 量子理论的历史发展2.1 古代对物质本质的认识在远古时代，人们对物质本质有着一些基本的认识。
早期的哲学家和科学家相信自然界由离散的、不可再分割的微粒组成，这种理论被称为原子论。
然而，在缺乏实验证据的情况下，这一观点往往只是纯粹的哲学推断。
2.2 光的波粒二象性的启示到了17世纪末，牛顿提出了光是由微小粒子组成并按直线传播的粒子理论。
但是，随后哈耳发现了光具有干涉和衍射等波动现象，这引起了人们对光性质的重新思考。
19世纪初期，杨振宁实验证明了光波动性质，并进一步证明了光在传播过程中存在干涉现象。
材料物理课件 (2)原子的波动理论
1) statistical hypothesis ∶
dw | |2 dV dV
dw dV Where | ψ | 2 is equal to the chance of finding the subject at a certain time and position.
Based the duality of light ， in 1926, Erwin Schrodinger(薛定谔)from Austria，Werner Karl Heisenberg(海森 伯)and Max Born(马克斯〃玻恩) from German built the quantum mechanics that is theory to help peoples understand the atom s34 x 1.321032 m mV 0.01 500 0.0001
IV、Wave function (波函数)
A wave function or wavefunction is a mathematical tool used in quantum mechanics to describe the momentary states of subatomic particles.
[Example 3] A ball with mass of0.01kg moves at
the velocity about 500m/s 。 If the deviation of the velocity is 0.01% ， what is the deviation of the ball’s position:
A
C
xp x pa sin
h