Chapter1.2-Properties-and-Changes-of-Matter (1)
感受数学之美的给孩子看的英文书
感受数学之美的给孩子看的英文书全文共3篇示例，供读者参考篇1Title: Exploring the Beauty of MathematicsIntroductionMathematics is more than just numbers and equations, it is a fascinating and intricate puzzle that challenges our minds and shapes the world around us. In this book, we will delve into the beauty of mathematics and explore its endless possibilities. Through engaging stories, colorful illustrations, and interactive activities, children will discover the magic of numbers and the wonders of geometry, algebra, and more.Chapter 1: The Power of PatternsFrom the mesmerizing spiral of a seashell to the symmetrical petals of a flower, patterns are everywhere in nature. In this chapter, children will learn how to recognize and create patterns using basic shapes and colors. Through hands-on activities such as drawing and coloring, they will develop a keen eye for symmetry and repetition.Chapter 2: The Joy of GeometryGeometry is the study of shapes and their properties, and it is the foundation of many mathematical concepts. In this chapter, children will explore the world of polygons, circles, and angles. They will learn how to measure and calculate areas and perimeters, and discover the beauty of tessellations and fractals.Chapter 3: The Wonder of NumbersNumbers are the building blocks of mathematics, and they hold endless mysteries waiting to be uncovered. In this chapter, children will learn about the history of numbers, from the ancient civilizations to modern mathematicians. They will explore the concepts of prime numbers, fractions, and decimals, and engage in fun games and puzzles to sharpen their numerical skills.Chapter 4: The Magic of AlgebraAlgebra is the language of equations and variables, and it is crucial for solving complex problems. In this chapter, children will embark on a journey through algebraic expressions, equations, and inequalities. They will learn how to simplify expressions, solve equations, and graph functions, giving them the tools to tackle real-world challenges with confidence.Chapter 5: The Beauty of CalculusCalculus is the study of change and motion, and it is a powerful tool for understanding the world around us. In this chapter, children will be introduced to the concepts of derivatives, integrals, and limits. They will explore the connection between calculus and physics, biology, and other sciences, and witness the beauty of mathematical modeling in action.ConclusionMathematics is a treasure trove of beauty and wonder, waiting to be explored by curious minds. By diving into the world of patterns, geometry, numbers, algebra, and calculus, children can unlock the secrets of the universe and unleash their creativity and problem-solving skills. This book is just the beginning of their mathematical journey, and I hope it inspires them to continue exploring the infinite possibilities of this fascinating field.篇2Title: Exploring the Beauty of Mathematics: A Book for ChildrenIntroductionMathematics is a beautiful and fascinating subject that is often misunderstood and feared by many children. However, it isessential to teach children about the beauty and wonders of mathematics from a young age to foster a love and appreciation for the subject. This book aims to introduce children to the beauty of mathematics in a fun and engaging way, helping them see the world through the lens of mathematics.Chapter 1: The Magic of NumbersIn this chapter, children will learn about the magic of numbers and how they are used in everyday life. From counting to discovering patterns and sequences, numbers are all around us. Children will explore the concept of symmetry, prime numbers, and the Fibonacci sequence, opening their minds to the beauty of mathematics.Chapter 2: The Language of ShapesShapes are everywhere, from the geometry of buildings to the symmetry of nature. In this chapter, children will learn about different geometric shapes, such as circles, squares, triangles, and polygons. They will discover the beauty of symmetry and tessellations, as well as the concept of fractals and the golden ratio.Chapter 3: The Art of Problem SolvingMathematics is not just about numbers and shapes but also about problem-solving. In this chapter, children will learn about different problem-solving strategies, such as breaking down a problem, looking for patterns, and using logical reasoning. They will explore puzzles, riddles, and games that challenge their minds and nurture their problem-solving skills.Chapter 4: The Power of PatternsPatterns are an essential part of mathematics, helping us make sense of the world around us. In this chapter, children will learn about different types of patterns, such as number patterns, shape patterns, and symmetry. They will discover how patterns are used in mathematics, art, music, and nature, showing them the interconnectedness of the world.Chapter 5: The Beauty of InfinityThe concept of infinity is both mind-boggling and beautiful. In this chapter, children will learn about different types of infinity, such as countable and uncountable infinity. They will explore the concept of limits, sequences, and series, as well as the infinite nature of fractals and the Mandelbrot set. Children will be amazed by the endless possibilities of infinity and its presence in mathematics and beyond.ConclusionMathematics is a subject full of wonder, beauty, and creativity. By introducing children to the beauty of mathematics at a young age, we can help them develop a love and appreciation for the subject. This book aims to inspire children to see the world through the lens of mathematics, encouraging them to explore, discover, and create with confidence and curiosity. Let's unlock the beauty of mathematics together and open the doors to endless possibilities.篇3Title: Discovering the Beauty of Mathematics: A Children's BookIntroduction:Mathematics is often seen as a difficult and intimidating subject, but in reality, it is a beautiful and fascinating field of study. Through this children's book, we aim to help young readers discover the beauty of mathematics and develop a deeper appreciation for the subject.Chapter 1: Introduction to MathematicsIn this chapter, we introduce the basic concepts of mathematics, such as numbers, shapes, and patterns. We explain how mathematics is all around us, from the natural world to the technology we use every day.Chapter 2: The Beauty of SymmetrySymmetry is a key concept in mathematics and can be found in nature, art, and architecture. In this chapter, we explore different types of symmetry and how they can be used to create beautiful designs.Chapter 3: Exploring PatternsMathematics is all about finding and understanding patterns. In this chapter, we look at different types of patterns, such as geometric patterns, number patterns, and fractals. We show how patterns can be both simple and complex, and how they can be found in nature and art.Chapter 4: The Magic of NumbersNumbers are the building blocks of mathematics, and they have many fascinating properties. In this chapter, we explore the beauty of numbers, from prime numbers to Fibonacci sequences. We also look at how numbers are used in everyday life, from telling time to measuring distances.Chapter 5: The Language of MathematicsMathematics has its own language, with symbols and equations that help us solve problems and communicate ideas. In this chapter, we introduce young readers to some basic mathematical symbols and show how they are used in equations.Chapter 6: The World of ShapesGeometry is a branch of mathematics that studies shapes and their properties. In this chapter, we explore different types of shapes, such as polygons, circles, and solids. We also look at how shapes are used in art and design.Conclusion:By the end of this book, we hope that young readers will have a better understanding of the beauty of mathematics and be inspired to explore the subject further. Mathematics is not just about solving equations - it is a way of thinking and seeing the world in a new light. We encourage children to embrace the beauty of mathematics and enjoy the journey of discovery that it offers.。
英语语言学概论
英语语言学概论GE GROUP system office room 【GEIHUA16H-GEIHUA GEIHUA8Q8-Chapter 1 Language语言1.Design feature (识别特征) refers to the defining properties of humanlanguage that distinguish it from any animal system of communication.2.Productivity (能产性) refers to the ability that people have in makingand comprehending indefinitely large quantities of sentences in their native language.3.arbitrariness (任意性) Arbitrariness refers to the phenomenon thatthere is no motivated relationship between a linguistic form and its meaning.4.symbol (符号) Symbol refers to something such as an object, word, orsound that represents something else by association or convention.5.discreteness (离散性) Discreteness refers to the phenomenon that thesounds in a language are meaningfully distinct.6.displacement (不受时空限制的特性) Displacement refers to the fact thathuman language can be used to talk about things that are not in theimmediate situations of its users.7.duality of structure (结构二重性) The organization of language into twolevels, one of sounds, the other of meaning, is known as duality ofstructure.8.culture transmission (文化传播) Culture transmission refers to the factthat language is passed on from one generation to the next throughteaching and learning, rather than by inheritance.9.interchangeability (互换性) Interchangeability means that any humanbeing can be both a producer and a receiver of messages.1.★What is language?Language is a system of arbitrary vocal symbols used for humancommunication. This definition has captured the main features of language.First, language is a system.Second, language is arbitrary in the sense.The third feature of language is symbolic nature.2.★What are the design features of language?Language has seven design features as following:1) Productivity.2) Discreteness.3) Displacement4) Arbitrariness.5) Cultural transmission6) Duality of structure.7) Interchangeability.3.Why do we say language is a system?Because elements of language are combined according to rules, and every language contains a set of rules. By system, the recurring patterns or arrangements or the particular ways or designs in which a languageoperates. And the sounds, the words and the sentences are used in fixed patterns that speaker of a language can understand each other.4.★ (Function of language.) According to Halliday, what are the initialfunctions of children’s language? And what are the three functional components of adult language?I.Halliday uses the following terms to refer to the initial functionsof children’s language:1) Instrumental function. 工具功能2) Regulatory function. 调节功能3) Representational function. 表现功能4) Interactional function. 互动功能5) Personal function. 自指性功能6) Heuristic function. 启发功能 [osbQtq`kf`h]7) Imaginative function. 想象功能II.Adult language has three functional components as following:1) Interpersonal components. 人际2) Ideational components.概念3) Textual components.语篇Chapter 2 Linguistics语言学1.general linguistics and descriptive linguistics (普通语言学与描写语言学)The former deals with language in general whereas the latter isconcerned with one particular language.2.synchronic linguistics and diachronic linguistics (共时语言学与历时语言学) Diachronic linguistics traces the historical development of thelanguage and records the changes that have taken place in it betweensuccessive points in time. And synchronic linguistics presents anaccount of language as it is at some particular point in time.3.theoretical linguistics and applied linguistics (理论语言学与应用语言学)The former copes with languages with a view to establishing a theory of their structures and functions whereas the latter is concerned with the application of the concepts and findings of linguistics to all sorts of practical tasks.4.microlinguistics and macrolinguistics (微观语言学与宏观语言学) Theformer studies only the structure of language system whereas the latter deals with everything that is related to languages.ngue and parole (语言与言语) The former refers to the abstractlinguistics system shared by all the members of a speech communitywhereas the latter refers to the concrete act of speaking in actualsituation by an individual speaker.petence and performance (语言能力与语言运用) The former is one’sknowledge of all the linguistic regulation systems whereas the latter is the use of language in concrete situation.7.speech and writing (口头语与书面语) Speech is the spoken form oflanguage whereas writing is written codes, gives language new scope.8.linguistics behavior potential and actual linguistic behavior (语言行为潜势与实际语言行为) People actually says on a certain occasion to acertain person is actual linguistics behavior. And each of possiblelinguistic items that he could have said is linguistic behaviorpotential.9.syntagmatic relation and paradigmatic relation (横组合关系与纵聚合关系)The former describes the horizontal dimension of a language while the latter describes the vertical dimension of a language.10.verbal communication and non-verbal communication (言语交际与非言语交际) Usual use of language as a means of transmitting information iscalled verbal communication. The ways we convey meaning without using language is called non-verbal communication.1.★How does John Lyons classify linguistics?According to John Lyons, the field of linguistics as a whole can be divided into several subfields as following:1) General linguistics and descriptive linguistics.2) Synchronic linguistics and diachronic linguistics.3) Theoretical linguistics and applied linguistics.4) Microlinguistics and macrolinguistics.2.Explain the three principles by which the linguist is guided:consistency, adequacy and simplicity.1) Consistency means that there should be no contradictions betweendifferent parts of the theory and the description.2) Adequacy means that the theory must be broad enough in scope to offersignificant generalizations.3) Simplicity requires us to be as brief and economic as possible.3.★What are the sub-branches of linguistics within the language system?Within the language system there are six sub-branches as following:1) Phonetics. 语音学 is a study of speech sounds of all human languages.2) Phonology. 音位学 studies about the sounds and sound patterns of aspeaker’s native language.3) Morphology. 形态学 studies about how a word is formed.4) Syntax. 句法学 studies about whether a sentence is grammatical or not.5) Semantics. 语义学studies about the meaning of language, includingmeaning of words and meaning of sentences.6) Pragmatics. 语用学★The scope of language: Linguistics is referred to as a scientific study of language.★The scientific process of linguistic study: It involves four stages: collecting data, forming a hypothesis, testing the hypothesis and drawing conclusions.Chapter 3 Phonetics语音学1.articulatory phonetics(发音语音学) The study of how speech organsproduce the sounds is called articulatory phonetics.2.acoustic phonetics (声学语音学) The study of the physical properties andof the transmission of speech sounds is called acoustic phonetics.3.auditory phonetics (听觉语音学) The study of the way hearers perceivespeech sounds is called auditory phonetics.4.consonant (辅音) Consonant is a speech sound where the air form thelanguage is either completely blocked, or partially blocked, or where the opening between the speech organs is so narrow that the air escapes with audible friction.5.vowel (元音) is defined as a speech sound in which the air from thelungs is not blocked in any way and is pronounced with vocal-cordvibration.6.bilabials (双唇音) Bilabials means that consonants for which the flow ofair is stopped or restricted by the two lips. [p] [b] [m] [w]7.affricates (塞擦音) The sound produced by stopping the airstream andthen immediately releasing it slowly is called affricates. [tX] [dY] [tr] [dr]8.glottis (声门) Glottis is the space between the vocal cords.9.rounded vowel (圆唇元音) Rounded vowel is defined as the vowel soundpronounced by the lips forming a circular opening. [u:] [u] [OB] [O]10.diphthongs (双元音) Diphthongs are produced by moving from one vowelposition to another through intervening positions.[ei][ai][Oi] [Qu][au]11.triphthongs (三合元音) Triphthongs are those which are produced bymoving from one vowel position to another and then rapidly andcontinuously to a third one. [eiQ][aiQ][OiQ] [QuQ][auQ]x vowels (松元音) According to distinction of long and short vowels,vowels are classified tense vowels and lax vowels. All the long vowels are tense vowels but of the short vowels,[e] is a tense vowel as well, and the rest short vowels are lax vowels.1. ★How are consonants classified in terms of different criteria?The consonants in English can be described in terms of four dimensions.1)The position of the soft palate.2)The presence or the absence of vocal-cord vibration.3)The place of articulation.4)The manner of articulation.2.★How are vowels classified in terms of different criteria?Vowel sounds are differentiated by a number of factors.1)The state of the velum2)The position of the tongue.3)The openness of the mouth.4)The shape of the lips.5)The length of the vowels.6)The tension of the muscles at pharynx.3.★What are the three sub-branches of phonetics? How do they differ fromeach other?Phonetics has three sub-branches as following:1)Articulatory phonetics is the study of how speech organs produce thesounds is called articulatory phonetics.2)Acoustic phonetics is the study of the physical properties and ofthe transmission of speech sounds is called acoustic phonetics.3)Auditory phonetics is the study of the way hearers perceive speechsounds is called auditory phonetics.4.★What are the commonly used phonetic features for consonants andvowels respectively?I. The frequently used phonetic features for consonants include thefollowing:1)Voiced.2)Nasal.3)Consonantal.4)Vocalic.5)Continuant.6)Anterior.7)Coronal.8)Aspirated.II. The most common phonetic features for vowels include the following:1)High.2)Low.3)Front.4)Back.5)Rounded.6)Tense.Chapter 4 Phonology 音位学1.phonemes (音位) Phonemes are minimal distinctive units in the soundsystem of a language.2.allophones (音位变体) Allophones are the phonetic variants andrealizations of a particular phoneme.3.phones (单音) The smallest identifiable phonetic unit found in a streamof speech is called a phone.4.minimal pair (最小对立体) Minimal pair means words which differ fromeach other only by one sound.5.contrastive distribution (对比分布) If two or more sounds can occur inthe same environment and the substitution of one sound for anotherbrings about a change of meaning, they are said to be in contrastive distribution.plementary distribution (互补分布) If two or more sounds neverappear in the same environment ,then they are said to be incomplementary distribution.7.free variation (自由变异) When two sounds can appear in the sameenvironment and the substitution of one for the other does not cause any change in meaning, then they are said to be in free variation.8.distinctive features (区别性特征) A distinctive feature is a featurewhich distinguishes one phoneme from another.9.suprasegmental features (超切分特征) The distinctive (phonological)features which apply to groups larger than the single segment are known as suprasegmental features.10.tone languages (声调语言) Tone languages are those which use pitch tocontrast meaning at word level.11.intonation languages (语调语言) Intonation languages are those whichuse pitch to distinguish meaning at phrase level or sentence level.12.juncture (连音) Juncture refers to the phonetic boundary featureswhich may demarcate grammatical units.1. ★What are the differences between English phonetics and English phonology?1)Phonetics is the study of the production, perception, and physicalproperties of speech sounds, while phonology attempts to account for how they are combined, organized, and convey meaning in particularlanguages.2)Phonetics is the study of the actual sounds while phonology isconcerned with a more abstract description of speech sounds and tries to describe the regularities of sound patterns.2.Give examples to illustrate the relationship between phonemes, phonesand allophones.When we hear [pit],[tip],[spit],etc, the similar phones we have heard are /p/. And /p/ and /b/ are separate phonemes in English, while [ph] and [p] are allophones.3.How can we decide a minimal pair or a minimal set?A minimal pair should meet three conditions:1)The two forms are different in meaning.2)The two forms are different in one sound segment.3)The different sounds occur in the same position of the two strings.4.★Use examples to explain the three types of distribution.1)Contrastive distribution. Sounds [m] in met and [n] in net are incontrastive distribution because substituting [m] for [n] willresult in a change of meaning.2)Complementary distribution. The aspirated plosive [ph] and theunaspirated plosive [p] are in complementary distribution becausethe former occurs either initially in a word or initially in astressed syllable while the latter never occurs in such environments.3)Free variation. In English, the word “direct” may be pro nounce intwo ways: /di’rekt/ and /dia’rekt/, and the two different sounds/i/ and /ai/ can be said to be in free variation.5.What’s the difference between segmental features and suprasegmentalfeatures? What are the suprasegmental features in English?I. 1) Distinctive features, which are used to distinguish one phonemefrom another and thus have effect on one sound segment, are referred to as segmental features.2) The distinctive (phonological) features which apply to groupslarger than the single segment are known as suprasegmental features.3) Suprasegmental features may have effect on more than one soundsegment. They may apply to a string of several sounds.II.The main suprasegmental features include stress, tone, intonation and juncture.6.What’s th e difference between tone languages and intonation language?Tone languages are those which use pitch to contrast meaning at word level while intonation languages are those which use pitch todistinguish meaning at phrase level or sentence level7.★What’s th e difference between phonetic transcriptions and phonemictranscriptions?The former was meant to symbolize all possible speech sounds, including even the most minute shades of pronunciation, while the latter wasintended to indicate only those sounds capable of distinguishing one word from another in a given language.Chapter 5 Morphology 形态学1.morphemes (语素) Morphemes are the minimal meaningful units in thegrammatical system of a language.allomorphs (语素变体) Allomorphs are the realizations of a particular morpheme.morphs (形素) Morphs are the realizations of morphemes in general and are the actual forms used to realize morphemes.2.roots (词根) Roots is defined as the most important part of a word thatcarries the principal meaning.affixes (词缀) Affixes are morphemes that lexically depend on roots and do not convey the fundamental meaning of words.free morphemes (自由语素) Free morphemes are those which can exist as individual words.bound morphemes (粘着语素) Bound morphemes are those which cannot occur on their own as separate words.3.inflectional affixes (屈折词缀) refer to affixes that serve to indicategrammatical relations, but do not change its part of speech.derivational affixes (派生词缀) refer to affixes that are added to words in order to change its grammatical category or its meaning.4.empty morph (空语子) Empty morph means a morph which has form but nomeaning.zero morph (零语子) Zero morph refers to a morph which has meaning but no form.5.IC Analysis (直接成分分析) IC analysis is the analysis to analyze alinguistic expression (both a word and a sentence) into a hierarchically defined series of constituents.6.immediate constituents (直接成分) A immediate constituent is any one ofthe largest grammatical units that constitute a construction. Immediate constituents are often further reducible.ultimate constituents (最后成分) Ultimate constituents are thosegrammatically irreducible units that constitute constructions.7.morphological rules (形态学规则) The principles that determine howmorphemes are combined into new words are said to be morphological rules.8.word-formation process (构词法) Word-formation process mean the rule-governed processes of forming new words on the basis of already existing linguistic resources.1. ★What is IC Analysis?IC analysis is the analysis to analyze a linguistic expression (both a word and a sentence) into a hierarchically defined series of constituents.2.How are morphemes classified?1)Semantically speaking, morphemes are grouped into two categories:root morphemes and affixational morphemes.2)Structurally speaking, they are divided into two types: freemorphemes and bound morphemes.3.★Explain the interrelations between semantic and structuralclassifications of morphemes.a)All free morphemes are roots but not all roots are free morphemes.b)All affixes are bound morphemes, but not all bound morphemes areaffixes.4.What’s the difference between an empty morph and a zero morph?a)Empty morph means a morph that has form but no meaning.b)Zero morph refers to a morph that has meaning but no form.5.Explain the differences between inflectional and derivational affixesin term of both function and position.a)Functionally:i.Inflectional affixes sever to mark grammatical relations and nevercreate new words while derivational affixes can create new words.ii.Inflectional affixes do not cause a change in grammatical class while derivational affixes very often but not always cause a change in grammatical class.b)In term of position:i.Inflectional affixes are suffixes while derivational affixes can besuffixes or prefixes.ii.Inflectional affixes are always after derivational affixes if both are present. And derivational affixes are always before inflectional suffixes if both are present.6.What are morphological rules? Give at least four rules with examples.The principles that determine how morphemes are combined into new words are said to be morphological rules.For example:a)un- + adj. ->adj.b)Adj./n. + -ify ->v.c)V. + -able -> adj.d)Adj. + -ly -> adv.Chapter 6 Syntax 句法学1.syntagmatic relations (横组关系) refer to the relationships betweenconstituents in a construction.paradigmatic relations (纵聚合关系) refer to the relations between the linguistic elements within a sentence and those outside the sentence.hierarchical relations (等级关系) refer to relationships between any classification of linguistic units which recognizes a series of successively subordinate levels.2.IC Analysis (直接成分分析) is a kind of grammatical analysis, which makemajor divisions at any level within a syntactic construction.labeled IC Analysis(标记法直接成分分析) is a kind of grammatical analysis, which make major divisions at any level within a syntactic construction and label each constituent.phrase markers (短语标记法) is a kind of grammatical analysis, which make major divisions at any level within a syntactic construction, and label each constituent while remove all the linguistic forms.labeled bracketing(方括号标记法) is a kind of grammatical analysis, which is applied in representing the hierarchical structure of sentences by using brackets.3.constituency (成分关系)dependency (依存关系)4.surface structures (表层结构)refers to the mental representation of alinguistic expression, derived from deep structure by transformational rules.deep structures (深层结构) deep structure of a linguistic expression isa theoretical construct that seeks to unify several related structures.5.phrase structure rules(短语结构规则)are a way to describe a givenlanguage's syntax. They are used to break a natural language sentence down into its constituent parts.6.transformational rules (转换规则)7.structural ambiguity (结构歧义)1.What are the differences between surface structure and deep structure?They are different from each other in four aspects:1)Surface structures correspond directly to the linear arrangements ofsentences while deep structures correspond to the meaningful grouping of sentences.2)Surface structures are more concrete while deep structures are moreabstract.3)Surface structures give the forms of sentences whereas deepstructures give the meanings of sentences.4)Surface structures are pronounceable but deep structures are not.2.Illustrate the differences between PS rules and T-rules.1) PS rules frequently applied in generating deep structures.2) T-rules are used to transform deep structure into surface structures.3.What’s the order of generating sentences? Do we start with surfacestructures or with deep structures? How differently are they generated?To generate a sentence, we always start with its deep structure, and then transform it into its corresponding surface structure.Deep structures are generated by phrase structure rules (PS rules) while surface structures are derived from their deep structures by transformational rules (T-rules).4.What’s the difference between a compulsory constituent and an optionalone?Optional constituents may be present or absent while compulsory constituents must be present.5.What are the three syntactic relations? Illustrate them with examples.1) Syntagmatic relations2) Paradigmatic relations.3) Hierarchical relations.Chapter 7 Semantics 语义学1.Lexical semantics (词汇语义学) is defined as the study of word meaningin language.2.Sense (意义) refers to the inherent meaning of the linguistic form.3.Reference(所指) means what a linguistic form refers to in the realworld.4.Concept (概念) is the result of human cognition, reflecting theobjective world in the human mind.5.Denotation(外延) is defined as the constant ,abstract, and basicmeaning of a linguistic expression independent of context and situation.6.Connotation(内涵) refers to the emotional associations which aresuggested by, or are part of the meaning of, a linguistic unit.ponential analysis (成分分析法) is the way to decompose the meaningof a word into its components.8.Semantic field(语义场) The vocabulary of a language is not simply alisting of independent items, but is organized into areas, within which words interrelate and define each other in various ways. The areas are semantic fields.9.Hyponymy (上下义关系) refers to the sense relation between a moregeneral, more inclusive word and a more specific word.10.Synonymy (同义关系) refers to the sameness or close similarity ofmeaning.11.Antonymy (反义关系) refers to the oppositeness of meaning.12.Lexical ambiguity (词汇歧义)13.Polysemy (多义性) refers to the fact that the same one word may havemore than one meaning.14.Homonymy(同音(同形)异义关系) refers to the phenomenon that wordshaving different meanings have the same form.15.Sentence semantics(句子语义学) refers to the study of sentencemeaning in language.1.What’s the criterion of John Lyons in classifying semantics into itssub-branches? And how does he classify semantics?In terms of whether it falls within the scope of linguistics, John Lyons distinguishes between linguistic semantics and non-linguistic semantics.According John Lyons, semantics is one of the sub-branches of linguistics; it is generally defined as the study of meaning.2.What are the essential factors for determining sentence meaning?1) Object, 2) concept, 3) symbol, 4) user, 5) context.3.What is the difference between the theory of componential analysis andthe theory of semantic theory in defining meaning of words?。
胶体化学专业英语
C. Properties of the solutions like colloids.
such as optical（光学的）, rheological（流变 的） properties.
(2) Lyophobic colloids： There is a interface between dispersed phase and continuous phase, the colloids are unstable thermodynamically.
From thermodynamics that spontaneous process occur in the direction of decreasing Gibbs free energy. Therefore， the separation of a two-phase dispersion system to form distinct（明显 不同的） layers（层） is a change in the direction of decreasing Gibbs free energy.
(2) Kinetic stability(动力稳定性)
Kinetic stability： The separation rate of two phases is slow enough that the thermodynamic instability is of very little. Two-phase dispersions will always spontaneously change into a smaller number of larger particles given sufficient time. (unstable)
专业英语电子版教材
Chapter 3 Inorganic Chemistry (28)3.1 The Atomic Nature of Matter (28)3.2 Electronic Structure of Atoms (30)3.3 Periodicity of Atomic Properties (32)3.5 Molecular Geometry and Bonding Theories......................................................... 错误！未定义书签。
3.6 Chemical Reactions................................................................................................. 错误！未定义书签。
3.7 The Behavior of Gases ............................................................................................ 错误！未定义书签。
3.8 Aqueous Reactions and Solution Stoichiometry................................................... 错误！未定义书签。
3.9 Chemical Equilibrium ............................................................................................ 错误！未定义书签。
3.10 Thermochemistry.................................................................................................. 错误！未定义书签。
伍德里奇《计量经济学导论--现代观点》1
T his appendix derives various results for ordinary least squares estimation of themultiple linear regression model using matrix notation and matrix algebra (see Appendix D for a summary). The material presented here is much more ad-vanced than that in the text.E.1THE MODEL AND ORDINARY LEAST SQUARES ESTIMATIONThroughout this appendix,we use the t subscript to index observations and an n to denote the sample size. It is useful to write the multiple linear regression model with k parameters as follows:y t ϭ1ϩ2x t 2ϩ3x t 3ϩ… ϩk x tk ϩu t ,t ϭ 1,2,…,n ,(E.1)where y t is the dependent variable for observation t ,and x tj ,j ϭ 2,3,…,k ,are the inde-pendent variables. Notice how our labeling convention here differs from the text:we call the intercept 1and let 2,…,k denote the slope parameters. This relabeling is not important,but it simplifies the matrix approach to multiple regression.For each t ,define a 1 ϫk vector,x t ϭ(1,x t 2,…,x tk ),and let ϭ(1,2,…,k )Јbe the k ϫ1 vector of all parameters. Then,we can write (E.1) asy t ϭx t ϩu t ,t ϭ 1,2,…,n .(E.2)[Some authors prefer to define x t as a column vector,in which case,x t is replaced with x t Јin (E.2). Mathematically,it makes more sense to define it as a row vector.] We can write (E.2) in full matrix notation by appropriately defining data vectors and matrices. Let y denote the n ϫ1 vector of observations on y :the t th element of y is y t .Let X be the n ϫk vector of observations on the explanatory variables. In other words,the t th row of X consists of the vector x t . Equivalently,the (t ,j )th element of X is simply x tj :755A p p e n d i x EThe Linear Regression Model inMatrix Formn X ϫ k ϵϭ .Finally,let u be the n ϫ 1 vector of unobservable disturbances. Then,we can write (E.2)for all n observations in matrix notation :y ϭX ϩu .(E.3)Remember,because X is n ϫ k and is k ϫ 1,X is n ϫ 1.Estimation of proceeds by minimizing the sum of squared residuals,as in Section3.2. Define the sum of squared residuals function for any possible k ϫ 1 parameter vec-tor b asSSR(b ) ϵ͚nt ϭ1(y t Ϫx t b )2.The k ϫ 1 vector of ordinary least squares estimates,ˆϭ(ˆ1,ˆ2,…,ˆk ),minimizes SSR(b ) over all possible k ϫ 1 vectors b . This is a problem in multivariable calculus.For ˆto minimize the sum of squared residuals,it must solve the first order conditionѨSSR(ˆ)/Ѩb ϵ0.(E.4)Using the fact that the derivative of (y t Ϫx t b )2with respect to b is the 1ϫ k vector Ϫ2(y t Ϫx t b )x t ,(E.4) is equivalent to͚nt ϭ1xt Ј(y t Ϫx t ˆ) ϵ0.(E.5)(We have divided by Ϫ2 and taken the transpose.) We can write this first order condi-tion as͚nt ϭ1(y t Ϫˆ1Ϫˆ2x t 2Ϫ… Ϫˆk x tk ) ϭ0͚nt ϭ1x t 2(y t Ϫˆ1Ϫˆ2x t 2Ϫ… Ϫˆk x tk ) ϭ0...͚nt ϭ1x tk (y t Ϫˆ1Ϫˆ2x t 2Ϫ… Ϫˆk x tk ) ϭ0,which,apart from the different labeling convention,is identical to the first order condi-tions in equation (3.13). We want to write these in matrix form to make them more use-ful. Using the formula for partitioned multiplication in Appendix D,we see that (E.5)is equivalent to΅1x 12x 13...x 1k1x 22x 23...x 2k...1x n 2x n 3...x nk ΄΅x 1x 2...x n ΄Appendix E The Linear Regression Model in Matrix Form756Appendix E The Linear Regression Model in Matrix FormXЈ(yϪXˆ) ϭ0(E.6) or(XЈX)ˆϭXЈy.(E.7)It can be shown that (E.7) always has at least one solution. Multiple solutions do not help us,as we are looking for a unique set of OLS estimates given our data set. Assuming that the kϫ k symmetric matrix XЈX is nonsingular,we can premultiply both sides of (E.7) by (XЈX)Ϫ1to solve for the OLS estimator ˆ:ˆϭ(XЈX)Ϫ1XЈy.(E.8)This is the critical formula for matrix analysis of the multiple linear regression model. The assumption that XЈX is invertible is equivalent to the assumption that rank(X) ϭk, which means that the columns of X must be linearly independent. This is the matrix ver-sion of MLR.4 in Chapter 3.Before we continue,(E.8) warrants a word of warning. It is tempting to simplify the formula for ˆas follows:ˆϭ(XЈX)Ϫ1XЈyϭXϪ1(XЈ)Ϫ1XЈyϭXϪ1y.The flaw in this reasoning is that X is usually not a square matrix,and so it cannot be inverted. In other words,we cannot write (XЈX)Ϫ1ϭXϪ1(XЈ)Ϫ1unless nϭk,a case that virtually never arises in practice.The nϫ 1 vectors of OLS fitted values and residuals are given byyˆϭXˆ,uˆϭyϪyˆϭyϪXˆ.From (E.6) and the definition of uˆ,we can see that the first order condition for ˆis the same asXЈuˆϭ0.(E.9) Because the first column of X consists entirely of ones,(E.9) implies that the OLS residuals always sum to zero when an intercept is included in the equation and that the sample covariance between each independent variable and the OLS residuals is zero. (We discussed both of these properties in Chapter 3.)The sum of squared residuals can be written asSSR ϭ͚n tϭ1uˆt2ϭuˆЈuˆϭ(yϪXˆ)Ј(yϪXˆ).(E.10)All of the algebraic properties from Chapter 3 can be derived using matrix algebra. For example,we can show that the total sum of squares is equal to the explained sum of squares plus the sum of squared residuals [see (3.27)]. The use of matrices does not pro-vide a simpler proof than summation notation,so we do not provide another derivation.757The matrix approach to multiple regression can be used as the basis for a geometri-cal interpretation of regression. This involves mathematical concepts that are even more advanced than those we covered in Appendix D. [See Goldberger (1991) or Greene (1997).]E.2FINITE SAMPLE PROPERTIES OF OLSDeriving the expected value and variance of the OLS estimator ˆis facilitated by matrix algebra,but we must show some care in stating the assumptions.A S S U M P T I O N E.1(L I N E A R I N P A R A M E T E R S)The model can be written as in (E.3), where y is an observed nϫ 1 vector, X is an nϫ k observed matrix, and u is an nϫ 1 vector of unobserved errors or disturbances.A S S U M P T I O N E.2(Z E R O C O N D I T I O N A L M E A N)Conditional on the entire matrix X, each error ut has zero mean: E(ut͉X) ϭ0, tϭ1,2,…,n.In vector form,E(u͉X) ϭ0.(E.11) This assumption is implied by MLR.3 under the random sampling assumption,MLR.2.In time series applications,Assumption E.2 imposes strict exogeneity on the explana-tory variables,something discussed at length in Chapter 10. This rules out explanatory variables whose future values are correlated with ut; in particular,it eliminates laggeddependent variables. Under Assumption E.2,we can condition on the xtjwhen we com-pute the expected value of ˆ.A S S U M P T I O N E.3(N O P E R F E C T C O L L I N E A R I T Y) The matrix X has rank k.This is a careful statement of the assumption that rules out linear dependencies among the explanatory variables. Under Assumption E.3,XЈX is nonsingular,and so ˆis unique and can be written as in (E.8).T H E O R E M E.1(U N B I A S E D N E S S O F O L S)Under Assumptions E.1, E.2, and E.3, the OLS estimator ˆis unbiased for .P R O O F:Use Assumptions E.1 and E.3 and simple algebra to writeˆϭ(XЈX)Ϫ1XЈyϭ(XЈX)Ϫ1XЈ(Xϩu)ϭ(XЈX)Ϫ1(XЈX)ϩ(XЈX)Ϫ1XЈuϭϩ(XЈX)Ϫ1XЈu,(E.12)where we use the fact that (XЈX)Ϫ1(XЈX) ϭIk . Taking the expectation conditional on X givesAppendix E The Linear Regression Model in Matrix Form 758E(ˆ͉X)ϭϩ(XЈX)Ϫ1XЈE(u͉X)ϭϩ(XЈX)Ϫ1XЈ0ϭ,because E(u͉X) ϭ0under Assumption E.2. This argument clearly does not depend on the value of , so we have shown that ˆis unbiased.To obtain the simplest form of the variance-covariance matrix of ˆ,we impose the assumptions of homoskedasticity and no serial correlation.A S S U M P T I O N E.4(H O M O S K E D A S T I C I T Y A N DN O S E R I A L C O R R E L A T I O N)(i) Var(ut͉X) ϭ2, t ϭ 1,2,…,n. (ii) Cov(u t,u s͉X) ϭ0, for all t s. In matrix form, we canwrite these two assumptions asVar(u͉X) ϭ2I n,(E.13)where Inis the nϫ n identity matrix.Part (i) of Assumption E.4 is the homoskedasticity assumption:the variance of utcan-not depend on any element of X,and the variance must be constant across observations, t. Part (ii) is the no serial correlation assumption:the errors cannot be correlated across observations. Under random sampling,and in any other cross-sectional sampling schemes with independent observations,part (ii) of Assumption E.4 automatically holds. For time series applications,part (ii) rules out correlation in the errors over time (both conditional on X and unconditionally).Because of (E.13),we often say that u has scalar variance-covariance matrix when Assumption E.4 holds. We can now derive the variance-covariance matrix of the OLS estimator.T H E O R E M E.2(V A R I A N C E-C O V A R I A N C EM A T R I X O F T H E O L S E S T I M A T O R)Under Assumptions E.1 through E.4,Var(ˆ͉X) ϭ2(XЈX)Ϫ1.(E.14)P R O O F:From the last formula in equation (E.12), we haveVar(ˆ͉X) ϭVar[(XЈX)Ϫ1XЈu͉X] ϭ(XЈX)Ϫ1XЈ[Var(u͉X)]X(XЈX)Ϫ1.Now, we use Assumption E.4 to getVar(ˆ͉X)ϭ(XЈX)Ϫ1XЈ(2I n)X(XЈX)Ϫ1ϭ2(XЈX)Ϫ1XЈX(XЈX)Ϫ1ϭ2(XЈX)Ϫ1.Appendix E The Linear Regression Model in Matrix Form759Formula (E.14) means that the variance of ˆj (conditional on X ) is obtained by multi-plying 2by the j th diagonal element of (X ЈX )Ϫ1. For the slope coefficients,we gave an interpretable formula in equation (3.51). Equation (E.14) also tells us how to obtain the covariance between any two OLS estimates:multiply 2by the appropriate off diago-nal element of (X ЈX )Ϫ1. In Chapter 4,we showed how to avoid explicitly finding covariances for obtaining confidence intervals and hypotheses tests by appropriately rewriting the model.The Gauss-Markov Theorem,in its full generality,can be proven.T H E O R E M E .3 (G A U S S -M A R K O V T H E O R E M )Under Assumptions E.1 through E.4, ˆis the best linear unbiased estimator.P R O O F :Any other linear estimator of can be written as˜ ϭA Јy ,(E.15)where A is an n ϫ k matrix. In order for ˜to be unbiased conditional on X , A can consist of nonrandom numbers and functions of X . (For example, A cannot be a function of y .) To see what further restrictions on A are needed, write˜ϭA Ј(X ϩu ) ϭ(A ЈX )ϩA Јu .(E.16)Then,E(˜͉X )ϭA ЈX ϩE(A Јu ͉X )ϭA ЈX ϩA ЈE(u ͉X ) since A is a function of XϭA ЈX since E(u ͉X ) ϭ0.For ˜to be an unbiased estimator of , it must be true that E(˜͉X ) ϭfor all k ϫ 1 vec-tors , that is,A ЈX ϭfor all k ϫ 1 vectors .(E.17)Because A ЈX is a k ϫ k matrix, (E.17) holds if and only if A ЈX ϭI k . Equations (E.15) and (E.17) characterize the class of linear, unbiased estimators for .Next, from (E.16), we haveVar(˜͉X ) ϭA Ј[Var(u ͉X )]A ϭ2A ЈA ,by Assumption E.4. Therefore,Var(˜͉X ) ϪVar(ˆ͉X )ϭ2[A ЈA Ϫ(X ЈX )Ϫ1]ϭ2[A ЈA ϪA ЈX (X ЈX )Ϫ1X ЈA ] because A ЈX ϭI kϭ2A Ј[I n ϪX (X ЈX )Ϫ1X Ј]Aϵ2A ЈMA ,where M ϵI n ϪX (X ЈX )Ϫ1X Ј. Because M is symmetric and idempotent, A ЈMA is positive semi-definite for any n ϫ k matrix A . This establishes that the OLS estimator ˆis BLUE. How Appendix E The Linear Regression Model in Matrix Form 760Appendix E The Linear Regression Model in Matrix Formis this significant? Let c be any kϫ 1 vector and consider the linear combination cЈϭc11ϩc22ϩ… ϩc kk, which is a scalar. The unbiased estimators of cЈare cЈˆand cЈ˜. ButVar(c˜͉X) ϪVar(cЈˆ͉X) ϭcЈ[Var(˜͉X) ϪVar(ˆ͉X)]cՆ0,because [Var(˜͉X) ϪVar(ˆ͉X)] is p.s.d. Therefore, when it is used for estimating any linear combination of , OLS yields the smallest variance. In particular, Var(ˆj͉X) ՅVar(˜j͉X) for any other linear, unbiased estimator of j.The unbiased estimator of the error variance 2can be written asˆ2ϭuˆЈuˆ/(n Ϫk),where we have labeled the explanatory variables so that there are k total parameters, including the intercept.T H E O R E M E.4(U N B I A S E D N E S S O Fˆ2)Under Assumptions E.1 through E.4, ˆ2is unbiased for 2: E(ˆ2͉X) ϭ2for all 2Ͼ0. P R O O F:Write uˆϭyϪXˆϭyϪX(XЈX)Ϫ1XЈyϭM yϭM u, where MϭI nϪX(XЈX)Ϫ1XЈ,and the last equality follows because MXϭ0. Because M is symmetric and idempotent,uˆЈuˆϭuЈMЈM uϭuЈM u.Because uЈM u is a scalar, it equals its trace. Therefore,ϭE(uЈM u͉X)ϭE[tr(uЈM u)͉X] ϭE[tr(M uuЈ)͉X]ϭtr[E(M uuЈ|X)] ϭtr[M E(uuЈ|X)]ϭtr(M2I n) ϭ2tr(M) ϭ2(nϪ k).The last equality follows from tr(M) ϭtr(I) Ϫtr[X(XЈX)Ϫ1XЈ] ϭnϪtr[(XЈX)Ϫ1XЈX] ϭnϪn) ϭnϪk. Therefore,tr(IkE(ˆ2͉X) ϭE(uЈM u͉X)/(nϪ k) ϭ2.E.3STATISTICAL INFERENCEWhen we add the final classical linear model assumption,ˆhas a multivariate normal distribution,which leads to the t and F distributions for the standard test statistics cov-ered in Chapter 4.A S S U M P T I O N E.5(N O R M A L I T Y O F E R R O R S)are independent and identically distributed as Normal(0,2). Conditional on X, the utEquivalently, u given X is distributed as multivariate normal with mean zero and variance-covariance matrix 2I n: u~ Normal(0,2I n).761Appendix E The Linear Regression Model in Matrix Form Under Assumption E.5,each uis independent of the explanatory variables for all t. Inta time series setting,this is essentially the strict exogeneity assumption.T H E O R E M E.5(N O R M A L I T Y O Fˆ)Under the classical linear model Assumptions E.1 through E.5, ˆconditional on X is dis-tributed as multivariate normal with mean and variance-covariance matrix 2(XЈX)Ϫ1.Theorem E.5 is the basis for statistical inference involving . In fact,along with the properties of the chi-square,t,and F distributions that we summarized in Appendix D, we can use Theorem E.5 to establish that t statistics have a t distribution under Assumptions E.1 through E.5 (under the null hypothesis) and likewise for F statistics. We illustrate with a proof for the t statistics.T H E O R E M E.6Under Assumptions E.1 through E.5,(ˆjϪj)/se(ˆj) ~ t nϪk,j ϭ 1,2,…,k.P R O O F:The proof requires several steps; the following statements are initially conditional on X. First, by Theorem E.5, (ˆjϪj)/sd(ˆ) ~ Normal(0,1), where sd(ˆj) ϭ͙ෆc jj, and c jj is the j th diagonal element of (XЈX)Ϫ1. Next, under Assumptions E.1 through E.5, conditional on X,(n Ϫ k)ˆ2/2~ 2nϪk.(E.18)This follows because (nϪk)ˆ2/2ϭ(u/)ЈM(u/), where M is the nϫn symmetric, idem-potent matrix defined in Theorem E.4. But u/~ Normal(0,I n) by Assumption E.5. It follows from Property 1 for the chi-square distribution in Appendix D that (u/)ЈM(u/) ~ 2nϪk (because M has rank nϪk).We also need to show that ˆand ˆ2are independent. But ˆϭϩ(XЈX)Ϫ1XЈu, and ˆ2ϭuЈM u/(nϪk). Now, [(XЈX)Ϫ1XЈ]Mϭ0because XЈMϭ0. It follows, from Property 5 of the multivariate normal distribution in Appendix D, that ˆand M u are independent. Since ˆ2is a function of M u, ˆand ˆ2are also independent.Finally, we can write(ˆjϪj)/se(ˆj) ϭ[(ˆjϪj)/sd(ˆj)]/(ˆ2/2)1/2,which is the ratio of a standard normal random variable and the square root of a 2nϪk/(nϪk) random variable. We just showed that these are independent, and so, by def-inition of a t random variable, (ˆjϪj)/se(ˆj) has the t nϪk distribution. Because this distri-bution does not depend on X, it is the unconditional distribution of (ˆjϪj)/se(ˆj) as well.From this theorem,we can plug in any hypothesized value for j and use the t statistic for testing hypotheses,as usual.Under Assumptions E.1 through E.5,we can compute what is known as the Cramer-Rao lower bound for the variance-covariance matrix of unbiased estimators of (again762conditional on X ) [see Greene (1997,Chapter 4)]. This can be shown to be 2(X ЈX )Ϫ1,which is exactly the variance-covariance matrix of the OLS estimator. This implies that ˆis the minimum variance unbiased estimator of (conditional on X ):Var(˜͉X ) ϪVar(ˆ͉X ) is positive semi-definite for any other unbiased estimator ˜; we no longer have to restrict our attention to estimators linear in y .It is easy to show that the OLS estimator is in fact the maximum likelihood estima-tor of under Assumption E.5. For each t ,the distribution of y t given X is Normal(x t ,2). Because the y t are independent conditional on X ,the likelihood func-tion for the sample is obtained from the product of the densities:͟nt ϭ1(22)Ϫ1/2exp[Ϫ(y t Ϫx t )2/(22)].Maximizing this function with respect to and 2is the same as maximizing its nat-ural logarithm:͚nt ϭ1[Ϫ(1/2)log(22) Ϫ(yt Ϫx t )2/(22)].For obtaining ˆ,this is the same as minimizing͚nt ϭ1(y t Ϫx t )2—the division by 22does not affect the optimization—which is just the problem that OLS solves. The esti-mator of 2that we have used,SSR/(n Ϫk ),turns out not to be the MLE of 2; the MLE is SSR/n ,which is a biased estimator. Because the unbiased estimator of 2results in t and F statistics with exact t and F distributions under the null,it is always used instead of the MLE.SUMMARYThis appendix has provided a brief discussion of the linear regression model using matrix notation. This material is included for more advanced classes that use matrix algebra,but it is not needed to read the text. In effect,this appendix proves some of the results that we either stated without proof,proved only in special cases,or proved through a more cumbersome method of proof. Other topics—such as asymptotic prop-erties,instrumental variables estimation,and panel data models—can be given concise treatments using matrices. Advanced texts in econometrics,including Davidson and MacKinnon (1993),Greene (1997),and Wooldridge (1999),can be consulted for details.KEY TERMSAppendix E The Linear Regression Model in Matrix Form 763First Order Condition Matrix Notation Minimum Variance Unbiased Scalar Variance-Covariance MatrixVariance-Covariance Matrix of the OLS EstimatorPROBLEMSE.1Let x t be the 1ϫ k vector of explanatory variables for observation t . Show that the OLS estimator ˆcan be written asˆϭΘ͚n tϭ1xt Јx t ΙϪ1Θ͚nt ϭ1xt Јy t Ι.Dividing each summation by n shows that ˆis a function of sample averages.E.2Let ˆbe the k ϫ 1 vector of OLS estimates.(i)Show that for any k ϫ 1 vector b ,we can write the sum of squaredresiduals asSSR(b ) ϭu ˆЈu ˆϩ(ˆϪb )ЈX ЈX (ˆϪb ).[Hint :Write (y Ϫ X b )Ј(y ϪX b ) ϭ[u ˆϩX (ˆϪb )]Ј[u ˆϩX (ˆϪb )]and use the fact that X Јu ˆϭ0.](ii)Explain how the expression for SSR(b ) in part (i) proves that ˆuniquely minimizes SSR(b ) over all possible values of b ,assuming Xhas rank k .E.3Let ˆbe the OLS estimate from the regression of y on X . Let A be a k ϫ k non-singular matrix and define z t ϵx t A ,t ϭ 1,…,n . Therefore,z t is 1ϫ k and is a non-singular linear combination of x t . Let Z be the n ϫ k matrix with rows z t . Let ˜denote the OLS estimate from a regression ofy on Z .(i)Show that ˜ϭA Ϫ1ˆ.(ii)Let y ˆt be the fitted values from the original regression and let y ˜t be thefitted values from regressing y on Z . Show that y ˜t ϭy ˆt ,for all t ϭ1,2,…,n . How do the residuals from the two regressions compare?(iii)Show that the estimated variance matrix for ˜is ˆ2A Ϫ1(X ЈX )Ϫ1A Ϫ1,where ˆ2is the usual variance estimate from regressing y on X .(iv)Let the ˆj be the OLS estimates from regressing y t on 1,x t 2,…,x tk ,andlet the ˜j be the OLS estimates from the regression of yt on 1,a 2x t 2,…,a k x tk ,where a j 0,j ϭ 2,…,k . Use the results from part (i)to find the relationship between the ˜j and the ˆj .(v)Assuming the setup of part (iv),use part (iii) to show that se(˜j ) ϭse(ˆj )/͉a j ͉.(vi)Assuming the setup of part (iv),show that the absolute values of the tstatistics for ˜j and ˆj are identical.Appendix E The Linear Regression Model in Matrix Form 764。
Oracle Fusion Middleware监控与管理：使用Java EE管理API为Oracl
Oracle® Fusion MiddlewareMonitoring and Managing With the Java EE Management APIs for Oracle WebLogic Server11g Release 1 (10.3.3)E13736-03April 2010This document describes the Java EE Management APIs which enable a softwaredeveloper to create a single Java program that can discover and browse resources,such as JDBC connection pools and deployed applications, on any Java EE Webapplication server.1Introduction and RoadmapThe Java EE Management specification describes a standard data model formonitoring and managing the runtime state of any Java EE Web application server andits resources. It includes standard mappings of the model through a Java EEManagement EJB Component (MEJB).The following sections describe the contents and organization of thisguide—Monitoring and Managing With the Java EE Management APIs for Oracle WebLogicServer:■Section1.1, "Document Scope and Audience"■Section1.2, "Guide to This Document"■Section1.3, "Related Documentation"1.1Document Scope and AudienceThis document is a resource for software developers who develop managementservices for Java EE applications and for software vendors who developJMX-compatible management systems. It also contains information that is useful forbusiness analysts and system architects who are evaluating WebLogic Server orconsidering the use of JMX for a particular application.The information in this document is relevant during the design and developmentphases of a software project. The document does not address production phaseadministration, monitoring, or performance tuning topics. For links to WebLogicServer documentation and resources for these topics, see Section1.3, "RelatedDocumentation".It is assumed that the reader is familiar with Java EE and general applicationmanagement concepts. This document emphasizes a hands-on approach to developinga limited but useful set of JMX management services. For information on applyingJMX to a broader set of management problems, refer to the JMX specification or otherdocuments listed in Section1.3, "Related Documentation".1.2Guide to This DocumentThis document is organized as follows:■This chapter, Section1, "Introduction and Roadmap," describes the scope and organization of this guide.■Section2, "Using the Java EE Management APIs on WebLogic Server," introduces JMX and describes common ways to use it in conjunction with other WebLogic Server management features.1.3Related DocumentationThe Sun Developer Network includes a Web site that provides links to books, white papers, and additional information on JMX:/javase/technologies/core/mntr-mgmt/javamanag ement/.To view the JMX 1.2 specification and API documentation, download it from/aboutJava/communityprocess/final/jsr003/index3.ht ml.To view the JMX Remote API 1.0 specification and API documentation, download it from/aboutJava/communityprocess/final/jsr160/index.htm l.For guidelines on developing other types of management services for WebLogic Server applications, see the following documents:■Using WebLogic Logging Services for Application Logging describes WebLogic support for internationalization and localization of log messages, and shows you how to use the templates and tools provided with WebLogic Server to create or editmessage catalogs that are locale-specific.■Configuring and Using the WebLogic Diagnostic Framework describes how system administrators can collect application monitoring data that has not been exposed through JMX, logging, or other management facilities.For guidelines on developing and tuning WebLogic Server applications, see the following documents:■Developing Applications with WebLogic Server is a guide to developing WebLogic Server applications.■Developing Manageable Applications with JMX describes how to create and register custom MBeans.2Using the Java EE Management APIs on WebLogic ServerThe Java EE Management APIs enable a software developer to create a single Java program that can discover and browse resources, such as JDBC connection pools and deployed applications, on any Java EE Web application server. The APIs are part of the Java EE Management Specification, which requires all Java EE Web application servers to describe their resources in a standard data model.The following sections describe how to use the Java EE Management APIs on WebLogic Server:■Section2.1, "Understanding the Java EE Management Model and APIs"■Section2.2, "The Java EE Management Model on WebLogic Server"■Section2.3, "Accessing the MEJB on WebLogic Server"2.1Understanding the Java EE Management Model and APIsIn the Java EE Management data model, each instance of a Web application server resource type is represented by a Java EE Managed Object (JMO). The Java EE Management Specification describes exactly which types of resources must be represented by a JMO. JMOs themselves contain only a limited set of attributes, which are used to describe the location of the object in the data model.Download the Java EE Management Specification from/aboutJava/communityprocess/final/jsr077/index.htm l.2.1.1JMO HierarchyThe data model organizes JMOs hierarchically in a tree structure. The root JMO isJ2EEDomain, which represents a collection of Web application server instances that are logically related. J2EEDomain contains the object names for all instances of theJ2EEServer JMO, each of which represents a server instance in the collection.Java applications can browse the hierarchy of JMOs, recursively querying for object names and looking up the JMOs that are named by the query results.2.1.2JMO Object NamesEach JMO instance is identified by a unique object name of typejavax.management.ObjectName. The names follow this pattern:domain:name=j2eeType=value,name=value,parent-j2eeType[,property=value]*For example, mydomain:J2EEtype=J2EEDomain,name=mydomainThe Java EE Management Specification describes exactly which name/value pairs must be in the object names for each JMO type.The object name for each child JMO contains name/value pairs from its parent JMO's object name. For example, if the JMO for a server instance is namedmydomain:j2eeType=J2EEServer,name=myserverthen the JMO for a servlet that is part of an application deployed on that server instance would be named:mydomain:J2EEApplication=myapplication,J2EEServer=myserver,WebModule=myapp_ mywebmodule,j2eeType=Servlet,name=myservlet_nameThe name/value pairs can appear in any order.2.1.3Optional Features of JMOsThe Java EE Management Specification, version 1.0, requires only that Web application servers implement JMOs and provide API access to the JMOs.Optionally, you can implement the JMOs to provide performance statistics, management operations, and to emit notifications when specified events occur.2.1.4Accessing JMOsA Java application accesses the JMOs throughjavax.management.j2ee.Management, which is the remote interface for the Management Enterprise Java Bean (MEJB).The Java EE Management Specification requires that the MEJB's home interface be registered in a server's JNIDI tree as ejb.mgmt.MEJB.See the API Reference for the javax.management.j2ee package:/javaee/6/docs/api/javax/management/j2ee/pack age-summary.html.2.2The Java EE Management Model on WebLogic ServerAs of version 9.0, WebLogic Server implements only the required features of the Java EE Management Specification, version 1.1. Therefore, the following limitations are in place:■None of the JMOs provide performance statistics, management operations, or emit notifications.■There are no mappings to the Common Information Model (CIM).■There are no mappings to an SNMP Management Information Base (MIB).The MEJB and JMOs are available only on the Administration Server. This is consistent with the Java EE Management Model, which assumes that most Java EE Web servers exist within some logically connected collection and that there is a central point within the collection for accessing or managing the server instances. From the Administration Server, a Java application can browse to the JMO that represents any resource on any server instance in the WebLogic Server domain.Because WebLogic Server implements its JMOs as a wrapper for its MBeans, any changes in a WebLogic Server MBean that corresponds to a JMO is immediately available through the Java EE Management APIs.For all JMO object names on WebLogic Server, the domain: portion of the object name corresponds to the name of the WebLogic Server domain.2.3Accessing the MEJB on WebLogic ServerTo retrieve monitoring data through the MEJB:1.Look up the javax.management.j2ee.ManagementHome interface throughthe Administration Servers JNDI tree under the name ejb.mgmt.MEJB.e ManagementHome to construct an instance ofjavax.management.j2ee.Management, which is the MEJB's remote interface.2.3.1Example: Querying Names of JMOsThe example class in accesses the MEJB for a WebLogic Server domain and invokes javax.management.j2ee.Management.queryNames method. This method returns the object name for all JMOs in the domain.Example 1Querying Names of JMOsimport java.io.IOException;import .MalformedURLException;import java.util.Iterator;import java.util.Set;import java.util.Properties;import javax.management.j2ee.Management;import javax.management.j2ee.ManagementHome;import javax.management.AttributeNotFoundException;import javax.management.InstanceNotFoundException;import javax.management.ObjectName;import javax.management.QueryExp;import javax.naming.Context;import javax.naming.InitialContext;import javax.naming.NamingException;import javax.ejb.CreateException;public class GetJMONames {static String url = "t3://localhost:7001";static String user = "weblogic";static String password = "weblogic";public static void main(String[] args) {try {getAllJMONames();}catch(Exception e){System.out.println(e);}}public static Management getMEJBRemote()throws IOException, MalformedURLException,NamingException,CreateException{Context context = getInitialContext();ManagementHome home = (ManagementHome)context.lookup("ejb.mgmt.MEJB");Management bean = home.create();return bean;}public static Context getInitialContext()throws NamingException{Properties p = new Properties();p.put(Context.INITIAL_CONTEXT_FACTORY,"weblogic.jndi.WLInitialContextFactory");p.put(Context.PROVIDER_URL, url);if (user != null) {p.put(Context.SECURITY_PRINCIPAL, user);if (password == null)password = "";p.put(Context.SECURITY_CREDENTIALS, password); }return new InitialContext(p);}public static void getAllJMONames(){try {Management rhome = getMEJBRemote();String string = "";ObjectName name = new ObjectName(string);QueryExp query = null;Set allNames = rhome.queryNames(name, query);Iterator nameIterator = allNames.iterator();while(nameIterator.hasNext()) {ObjectName on = (ObjectName)nameIterator.next();System.out.println(on.getCanonicalName() + "\n");}} catch (Exception ex) {ex.printStackTrace();}}}3ConventionsThe following text conventions are used in this document:4Documentation AccessibilityOur goal is to make Oracle products, services, and supporting documentation accessible to all users, including users that are disabled. 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Oracle USA, Inc., 500 Oracle Parkway, Redwood City, CA 94065.This software is developed for general use in a variety of information management applications. It is not developed or intended for use in any inherently dangerous applications, including applications which may create a risk of personal injury. If you use this software in dangerous applications, then you shall be responsible to take all appropriate fail-safe, backup, redundancy, and other measures to ensure the safe use of this software. Oracle Corporation and its affiliates disclaim any liability for any damages caused by use of this software in dangerous applications.Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners.This software and documentation may provide access to or information on content, products, and services from third parties. 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斯蒂芬·威廉森-宏观经济学第五版答案chapter5
Chapter 5A Closed-Economy One-PeriodMacroeconomic Model⏹Teaching GoalsThere are three key points to be learned from this chapter. The first point is that when we allow the consumers and firms that we studied in Chapter 4 to interact with each other and with the government, the economy is able to achieve equilibrium through price adjustment. In this particular case, the “price” is the relative price of leisure, the real wage. The second important point is that the equilibrium that markets settle upon is a favorable one, in the sense of Pareto optimality. This point is in keeping with Adam Smith’s notion that the “invisible hand” of self-interested individuals, meeting in a competitive market, can work for the common good. The third point is that we can directly discover the equilibrium position of a market economy by solving an economic planner problem. Although students may find this point to be somewhat arcane, stress the point that it will be much simpler to solve problems (e.g., exam problems) by working with a planner problem as opposed to directly solving general equilibrium problems. The students, however, need to be aware when this solution method is not applicable. The section about the Laffer curve is a good way to show when social and private optima do not coincide.Once students have mastered the mechanics of the model, the two problems for which this model is best suited are the analyses of changes in government spending and total factor productivity. In working these problems, stress the applicability of these results to historical applications and as a guide to understanding current events.A key tactic of the textbook’s approach is the critical assessment of the usefulness and credibility of competing models. Therefore, it is important to stress the extent to which models fit the facts. Does this model fit the facts of long-run growth? Does this model fit the facts of the typical business cycle? These kinds of questions come up again and again in the course of macroeconomic study. Stress again and again that scientific study needs to relate to observations, in our case the stylized facts of Chapter 2.⏹Classroom Discussion TopicsAn alternative approach to this material is to start with the example of Robinson Crusoe (or Castaway, Gilligan’s Island, etc.). Does an isolated individual have any economic choices? What would guide these choices? Would you rather be on an island with a more plentiful food supply? A pure income effect can then be presented in the form of extra food (or a volleyball) washing up on shore, or in the form of “pirates” (government?) demanding tribute. An increase in total factor productivity can be in the form of obtaining a fishing net or a ladder to climb coconut trees. A change in capital can be the consequence of a hurricane, etc. The next step would be to ask the students about the likely consequences of additional individuals on the island. If they are all identical, and there are no economies to team production, will there be any reason for markets to exist? Could a market improve things? How and why? Typically, markets improve things onlyChapter 5 A Closed-Economy One-Period Macroeconomic Model 39 to the extent that people are different. However, these types of differences are what we are willing toignore when we adopt the fiction of a representative consumer.OutlineI. Competitive EquilibriumA. A One-Period Model1. No Borrowing or Lending2. G = TB. Equilibrium Modeling1. Endogenous Variables2. Exogenous Variables3. Hypothetical ExperimentsC. Properties of a Competitive Equilibrium1. Representative Consumer Maximizes Utility Subject to Budget Constraint2. Representative Firm Maximizes Profits3. Markets Clear4. Government Budget Constraint Satisfied5. ,,l C l CN w MRS MRT MP === II. OptimalityA. Pareto OptimalityB. Welfare Theorems1. 1st Theorem: A Competitive Equilibrium Can Be Pareto Optimal2. 2nd Theorem: A Pareto Optimum Can Be a Competitive EquilibriumC. Inefficiencies1. Externalities2. Distorting Taxes3. Monopoly PowerD. Using the Second Theorem1. Pareto Optima Are Easier to Identify2. Effects of Disturbances on Pareto OptimaIII. Effects of an Increase in Government SpendingA. Impact Effect1. Parallel Downward Shift in PPF2. Pure Income EffectB. Equilibrium Effects1. Reduced Consumption2. Reduced Leisure and Increased Hours of Work3. Increased Output4. Lower Real WageC. Crowding-OutD. Government Spending a Source of Business Cycles?40 Williamson • Macroeconomics, Fifth Edition1. Government Spending Shocks Wrongly Predict Countercyclical Consumption2. Government Spending Shocks Wrongly Predict Countercyclical Real WagesIV. Effects of an Increase in Total Factor ProductivityA. Impact Effect1. Upward Shift in PPF2. Steeper PPF3. Income and Substitution EffectsB. Equilibrium Effects1. Increased Consumption2. Leisure and Hours Worked May Rise or Fall3. Increased Output4. Higher Real WageC. Productivity and Long-Run Growth1. Consumption Grows over Time2. Hours Worked Remain about Constant3. Output Increases over Time4. Real Wages Rise over TimeD. Productivity as Source of Business Cycles?1. Consumption Is Procyclical2. Cyclical Properties of Hours Workeda. Procyclical Hours Worked Is a Business Cycle Factb. Need Strong Substitution Effect to Predict Procyclical Hoursc. Intertemporal Substitution of Leisure3. Increased Output Defines the Cycle4. Procyclical Real Wage RateV. Income Tax Revenue and the Laffer CurveA. Tax Revenue1. The Tax Base Depends on the Proportional Tax Rate2. The Laffer Curve Measures Tax Revenue as a Function of the Tax Rate3. Unless the Tax Rate Is Optimal, Two Tax Rates Yield the Same Tax Revenue4. Supply-Side Economists Claim the U.S. Economy Is at the Bad Tax Rate5. Empirical Evidence Tends to Prove Supply-Side Economists WrongVI. A Model of Public Goods: How Large Should the Government Be?A. Effects of higher GDP on optimal government spending.B. Better government technology: what happens to optimal government spending and private spending?Chapter 5 A Closed-Economy One-Period Macroeconomic Model 41 Solutions to End-of-Chapter Problems1. Although we often think about the negative externalities of congestion and pollution in cities, theremay also be some positive externalities. A concentrated population is better able to support the arts and professional sports; cities typically have a greater variety of good restaurants, etc. Perhaps a more basic issue is that there may be some increasing returns to scale at low output levels that makeindustrial production more costly in small towns. There may also be externalities in production in being located close to other producers. One example would be the financial industry in financialcenters like New York, London, Tokyo, etc. Another example would be large city medical centers that enhance coordination between primary physicians and specialists.One market test of whether productivity is higher in cities would be to look at the wages in cities versus the wages in smaller towns and rural areas. Wages are often higher in cities for individuals of comparable skills. Market efficiency suggests that the higher wages be reflective of a higher marginal product of labor, and that the higher wages compensate those choosing to live in cities for thenegative externalities that they face.2. In a one period model, taxes must be exactly equal to government spending. A reduction in taxes istherefore equivalent to a reduction in government spending. The result is exactly opposite of the case of an increase in government spending that is presented in the text. A reduction in governmentspending induces a pure income effect that induces the consumer to consume more and work less. At lower employment, the equilibrium real wage is higher because the marginal product of labor rises when employment falls. Output falls, consumption rises, employment falls and the real wage rises. 3. The only impact effect of this disturbance is to lower the capital stock. Therefore, the productionpossibility frontier shifts down and the marginal product of labor falls (PPF is flatter).(a) The reduction in the capital stock is depicted in the figure below. The economy starts at point Aon PPF1. The reduction in the capital stock shifts the production possibilities frontier to PPF2.Because PPF2 is flatter, there is a substitution effect that moves the consumer to point D. Theconsumer consumes less of the consumption good and consumes more leisure. Less leisure alsomeans that the consumer works more. Because the production possibilities frontier shifts down,there is also an income effect. The income effect implies less consumption and less leisure (more work). On net, consumption must fall, but leisure could decrease, remain the same, or increase,depending on the relative strengths of the income and substitution effect. The real wage must also fall. To see this, we must remember that, in equilibrium, the real wage must equal the marginalrate of substitution. The substitution effect implies a lower marginal rate of substitution. Theincome effect is a parallel shift in the production possibilities frontier. As the income effectincreases the amount of employment, marginal product of labor must fall from point D topoint B. This reinforces the reduction in the marginal rate of substitution from point A to point D.42 Williamson • Macroeconomics, Fifth Edition(b) Changes in the capital stock are not likely candidates for the source of the typical businesscycle. While it is easy to construct examples of precipitous declines in capital, it is more difficult to imagine sudden increases in the capital stock. The capital stock usually trends upward, and this upward trend is important for economic growth. However, the amount of new capital generatedby a higher level of investment over the course of a few quarters, of a few years, is very small in comparison to the existing stock of capital. On the other hand, a natural disaster that decreasesthe stock of capital implies lower output and consumption, and also implies lower real wages,which are all features of the typical business cycle contraction.4. Government Productivity. First consider the benchmark case in which 1,z = and there is no effect ofchanges in z on government activities. Now suppose that z increases. This case of an increase in z is depicted in the figure below. The original production possibilities frontier is labeled PPF 1 and the competitive equilibrium is at point A. If the increase in z only affects the economy through thechange in (,),zF K N then the new production possibilities frontier is PPF 2. The diagram shows a case in which the income and substitution effects on leisure exactly cancel out, and the economy moves to point B. The equation for the production possibilities frontier is (,).C zF K h l T =−− In the benchmark case, T G = and so we have (,).C zF K h l G =−− For this problem, /,T G z = and so the production possibilities frontier is given by (,)/.C zF K h l G z =−− When 1,z = the two PPFscoincide. When z increases, the vertical intercept of the PPF increases by /.G z ∆ Therefore, the new PPF is PPF 3 in the figure below. The competitive equilibrium is at point C . There is an additional income effect that provides an additional increase in equilibrium consumption, and a reinforcedincome effect that tend to make leisure increase. Therefore, relative to the benchmark case, there is a larger increase in consumption, and either a smaller decrease in leisure or a larger increase in leisure.Chapter 5 A Closed-Economy One-Period Macroeconomic Model 435. Change in preferences.(a) At the margin, the consumer decides that leisure is more preferred to consumption. That is, theconsumer now requires a bigger increase in consumption to willingly work more (consume less leisure). In more intuitive language, the consumer is lazier.(b) To work out the effects of this change in tastes, we refer to the figure below. The productionpossibility frontier in this example is unchanged. The consumer now picks a new point at which one of the flatter indifference curves is tangent to the production possibilities frontier. That is,equilibrium will shift from point A to point B. Consumption falls and leisure rises. Therefore, the consumer works less and produces less. Because employment has fallen, it also must be the case that the real wage increases.44 Williamson • Macroeconomics, Fifth Edition(c) This disturbance, which some might characterize as a contagious outbreak of laziness, wouldhave the appearance of a recession, as output and employment both fall. The consequentreduction in consumption is also consistent with a typical recession. However, in this case thereal wage would rise, which is inconsistent with the business cycle facts. Therefore, this type of preference change is not a cause of recessions.6. Production-enhancing aspects of government spending.(a) The increase in government spending in this example has two separate effects on the productionpossibilities frontier. First, the increase in government spending from G1 to G2 implies a parallel downward shift in the production possibilities frontier. Second, the productive nature ofgovernment spending is equivalent to an increase in total factor productivity that shifts theproduction possibilities frontier upward and increases its slope. The figure below draws theoriginal production possibilities frontier as PPF1 and the new production possibilities frontier as PPF2. If the production-enhancing aspects of the increase in government spending are largeenough, representative consumer utility could rise, as in this figure.Chapter 5 A Closed-Economy One-Period Macroeconomic Model 45(b) There are three effects at work in this example. First, there is a negative income effect from theincrease in taxes needed to pay for the increased government spending. This effect tends to lower both consumption and leisure. Second, there is a substitution effect due to the productive effect of the increase in G, which is drawn as the movement from point A to point D. This effect tends to increase both consumption and leisure. Third, there is a positive income effect from the increase in G on productivity. This effect tends to increase both consumption and leisure. In the figure above, the movement from point D to point B is the net effect of the two income effects. Ingeneral, consumption may rise or fall, and leisure may rise or fall. The overall effect on output is the same as in any increase in total factor productivity. Output surely rises.46 Williamson • Macroeconomics, Fifth Edition7. (a) If households dedicate a hours to education today, it reduces the hours available for leisure andwork to h−a. The PPF has to start form point (−G, h−a). Graphically, this corresponds to thefigure in the answer of question 6(b). The consequence is thus a reduction in consumption,leisure, employment, aggregate output, but an increase in the real wage.(b) In the future, workers will be more efficient, which corresponds to an increase in total factorproductivity. Thus we have the case described in Figure 5.9 of the textbook. There is an increase in future consumption, aggregate output and the real wage. Changes in employment and leisureare ambiguous.(c) An increase in education leads to an immediate loss in welfare, as both leisure and consumptionare reduced. But this is compensated by an increase in future consumption, and possibly ofleisure, too. Whether this is worth doing depends on the preferences of households over currentand future utility.8. We need to analyze each case separately. Start with the good equilibrium. As government expensesincrease, more tax revenue needs to be raised, and thus the tax rate needs to be increased. As shown in the figure below, this tilts down the linear PPF. The new equilibrium leads to a lower indifferencecurve. This leads to a negative income effect and a lower wage (remember, it is z(1 − t)), thus asubstitution effect. The income effect lowers consumption and leisure, the substitution effectdecreases consumption and increases leisure. All in all, consumption is lower and leisure is higher, as we know that the substitution effect dominates the income effect. This means that the labor supply is reduced, and thus equilibrium labor and output.The story is different in the bad equilibrium. To increase tax revenue, one needs to reduce the tax rate. Then all the changes discussed above are exactly in the opposite direction.9. We know from previous analysis that an improvement in total factor productivity pushes up the PPF,and thus leads to an increase in consumption, a decrease in leisure, and thus an increase in thequantity of labor supplied. This increases the tax base, and thus allows a reduced tax rate to achieve the same tax revenue, or in other words, it pushes the left portion of the Laffer curve to the left. The reduction in the tax rate has then a further impact on the variables of interest: as we saw in question 7, first part with a reversal of all signs: consumption increases even more and leisure decrease yet more, leading to an even higher quantity of labor. All in all, as both labor and total factor productivityincrease, output increases.Chapter 5 A Closed-Economy One-Period Macroeconomic Model 47 10. a) With perfect substitutes preferences, indifference curves are straight lines with slope –b, where b is the marginal rate of substitution. If b > 1/q, so that the indifference curves are steeper than the PPF, then the optimal choice for the government is G=qY, so that C = 0. Thus if b is relatively large (the consumer cares relatively more about public goods relative to private goods) and q is relatively large (the government is relatively efficient), then all production should be carried on by the government. Alternatively if b < 1/q, then G = 0 and C = Y, so that government is inactive. Thus, if b increases or q increases, this makes it more likely that b > 1/q and we have the first case, where all production comes from the government.b) With perfect complements, indifference curves are as depicted in Figure 10.1, and the initial equilibrium is at point A. If a increases, then the equilibrium shifts from A to B in Figure 10.2. An increase in a represents a greater preference for private goods relative to public goods, and in Figure 10.2, this results in less public goods and more private consumption in equilibrium. If q increases, this shifts the PPF out as in Figure 10.3, and the equilibrium shifts from A to B. Both C and G increase, driven by income effects.Figure 10.1Figure 10.248 Williamson • Macroeconomics, Fifth Edition ©2014 Pearson Education, Inc.Figure 10.311. (a) If public goods and private goods are perfect substitutes, then the consumer always chooses C and l so that C = dl , and so given the production possibilities frontier, we must haveC C h G d =−− and so()1d h G C d −=+ and 1h G l d −=+ Therefore, consumption and leisure both decrease when government spending increases – a pure incomeeffect.(b) However, suppose that public goods and private goods are perfect complements. As in part (a), it is always optimal for the consumer to choose C and l so that C = dl. But the consumer faces a tax T = G , and the wage is w=1. So, if the consumer chooses the C = dl and the budget constraint is satisfied, then ()1d h G C d −=+ and1h G l d −=+,just as in part (a). This is the only optimum if,C aG ≤orChapter 5 A Closed-Economy One-Period Macroeconomic Model 49 ©2014 Pearson Education, Inc.(1)dh G a d d ≥++ But, if (1)dh G a d d≤++ Then, it is optimal for the consumer to chooseC aG = and aG l d=. In this case, the consumption bundle of the consumer actually lies inside the production possibilitiesfrontier, and government spending has a Keynesian effect. More government spending implies greater consumption.。
材料成型及控制工程专业英语- 1.MATERIALS AND THEIR PROPERTIES
但是由于材料的塑性好，金属可以在这些位置产生塑性变形， 即：裂纹尖端产生硬化，会推迟断裂过程的产生。
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CHAPTER 1 MATERIALS AND THEIR PROPERTIES
This does not occur in non-metals．They are uncapable of plastic deformation and self-strengthening. Therefore, fracture（断裂） will occur as soon as the stresses at the tip of a defect exceed a definite value．
The majority of engineering designs that require structural load support or power transmission involve ferrous alloys．
工程设计中主要要求铁合金能够承受结构载荷或进行能量传 输。
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人类所用的金属材料中90％的都为铁合金。这则说明功能材 料种类繁多，其组织和性能也各种各样。
Note：the long sentence should be decomposed into clause ( short sentence).
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CHAPTER 1 MATERIALS AND THEIR PROPERTIES
由于各种关键零部件的可靠性要求高，均用金属而不是玻璃、 塑料或石头制造。
is required 翻译时将英文中的被动语态，改译为汉语中的主 动语态。
材料成型及控制工程专业英语--1.MATERIALS-AND-THEIR-PROPERTIES解析
1.1 Metals and Non-metalsWords and termsdefinite－确定的、明确的defect－缺陷plastic deformation塑性变形stress concentrator 应力集中点self-strengthening自强化the tip of a crock裂纹尖端☐Among numerous properties possessed by materials，their mechanical properties，in the majority of cases，are the most essential and therefore，they will be given much consideration in the book．☐在一些主要应用场合，机械性能是材料的各种性能中最重要的性能，因此，本书中将重点讨论。
▪consideration 考虑，需要考虑的事项，报酬☐All critical parts and elements，of which a high reliability （可靠性）is required，are made of metals, rather than of glass，plastics or stone.☐由于各种关键零部件的可靠性要求高，均用金属而不是玻璃、塑料或石头制造。
▪is required 翻译时将英文中的被动语态，改译为汉语中的主动语态。
▪rather than 而不是☐As has been given in Sec.1-1，metals are characterized by the metallic bond（金属键），where positive ions （正离子）occupy the sites of the crystal lattice （晶格）and are surrounded by electron gas（电子云）．☐正如Sec1-1中所说，金属主要由金属键组成（其特征主要……）。
初三化学第一章知识点总结
初三化学第一章知识点总结Chapter 1: XXX ChemistryTopic 1: Changes and Properties of MatterI。
Changes of Matter1.n: Physical change - a change that does not XXX: melting of wax。
freezing of water。
and n of gasoline。
Chemical change - a change that XXX: n of coal。
rusting of iron。
food spoilage。
and n.2.Criteria for judging changes: XXX are generated。
If yes。
it is a chemical change。
if not。
it is a physical change.3.nship een changes: XXX changes。
but physical changes do not XXX.4.XXX panying chemical changes: Release of heat。
n of heat。
n of light。
change of color。
n of gas。
and n of precipitate.XXX1.Physical properties: XXX。
These include color。
state。
odor。
melting point。
boiling point。
density。
hardness。
XXX。
XXX。
etc.2.Chemical properties: XXX。
acidity。
etc.III。
Differences and ns een physical changes。
chemical changes。
physical properties。
化工热力学导论英文课件1Introduction to chemical and engineering thermodynamics
It is very important to remember the conversion factors between different units system.
EMPHASES Notions of various thermodynamic properties and functions
DIFFICULIES Dimensions and units, the conversions and conversion factors
between the units
SI: (International system of units)
In this system:
The second, symbol s, is the duration of 9,192,632,770 cycles of radiation associated with a specified transition of the cesium( 铯) atom.
化工热力学英文版 chemical and engineering thermodynamics
Introduction to chemical and engineering thermodynamics
goals
Enforce your understanding of some notions of physical chemistry and principles of chemical engineering Improve your reading, comprehension and grasp of book with English version Cultivate your ability in doing assignment, answering question in English Make you familiar with English expression of technology Make you more fluently to communicate with the people with the same studying background
大学热动专业英语1-2章翻译
Specialized English for Thermal Energy & Power EngineeringCOURSE OUTLINETextbook: 热能与动力工程专业英语（Specialized English for Thermal Energy & Power Engineering）(3th) 阎维平，中国电力出版社（第三版）COURSE OUTLINECourse Goals:1.To understand the basic characteristics of Specialized English.2.To recognize some technical words in thermal energy and power engineering.3.To know how to write the abstract for a paper or a thesis (P155).Grading:Exercises in the class 20%Final exam 80%ContentsChapter 1 Introduction to Thermal Sciences1.1 Fundamental of engineering thermodynamics1.2 Fundamental of fluid mechanics1.3 Fundamental of heat transferChapter 2 Boiler2.1 Introduction2.2 Development of utility boiler2.3 Fuel and combustion2.4 Pulverizing system2.5 System arrangement and key components2.6 On-load cleaning of boilers2.7 Energy balanceChapter 1 Introduction to Thermal Sciences1.1 Fundamental of engineering thermodynamics•Thermodynamics is a science in which the storage, transformation, and transfer of energy are studied. Energy is stored as internal energy( associated with temperature), kinetic energy( due to motion), potential energy (due to elevation) and chemical energy( due tochemical composition); it is transformed from one of these forms to another; and it is transferred across a boundary as either heat or work.第一章热科学介绍1.1 工程热力学基础热力学是一门研究能量储存、转换及传递的科学。
流体力学(英文资料)
A380 73×79.8× 24.2 (m)
An-225 84×88.4×18.1 (m)
How can an airplane fly?
A turbofan(涡扇) jet engine
；
CFM56 in MTU
What is Fluid Mechanics ?
Fluid Mechanics is the study of fluid either in motion (Fluid Dynamics 流体动力学) or at rest(Fluid Statics 流 体静力学) and subsequent effects of the fluid upon the boundaries, which may be either solid surfaces or interfaces with other fluids.
Ludwig Prandtl (1875-1953)
Boundary layer theory(1904)
To be the single most important tool in modern flow analysis.
The father of modern fluid mechanics
19th century
Navier (1785-1836) & Stokes (1819-1905)
N-S equation
Reynolds (1842-1912) Turbulence Famous experiment on transition Reynolds Number
20th century
Any shear stress applied to a fluid, no matter how small, will result in motion of that fluid. The fluid moves and deforms continuously as long as the shear is applied.
Quantitative Genetics
Genetic constitution of a population
Chapter 2
Changes of gene frequency
Chapter 3
Change of gene frequency in small populations -----The idealized population
If the gene frequencies among males and among females are different , the population is not equilibrium. The gene frequency in the population as a whole does not change ,but its distribution between the two sexes oscillates as the population approaches equilibrium.如果在男性和女性之间的不同基因的频率，人口不平衡。在种
The genetic constitution of population ,referring to the genes it carries ,is described by the array of gene frequency ;that is ,by specification of the alleles present at every locus and the numbers or proportions of the different of alleles at each locus. 群体的遗传体质，参照它所携带的基因，通过基因 频率的阵列中所述的，也就是说，通过规范存在于每个基因座和等位基 因的不同的数字或比例在每个基因座上的等位基因。
Chapter 01 An Introduction to Machine Design 机械设计课件
Chapter 1 An Introduction to Machine Design
17
1.1.2 Function Composition of Machines 机器的功能组成
作为一部完整的机器，仅具有上述的机械部分是不够的， 它不能完成预期的工作。从功能和系统的角度来看，机器一 般主要由五部分组成，如下图所示。
1
Chapter 1 An Introduction to Machine Design
Chapter 1 An Introduction to Machine Design
内燃机车 高速列车
Chapter 1 An Introduction to Machine Design
4
Chapter 1 An Introduction to Machine Design
1.2.1 Contents of the Course
机械设计课程是一门研究机械基本理论和设计技术的课 程。本课程研究的对象是机器和机构,课程的主要内容有以下 几个方面。
(1) Basic Theory for Design
主要介绍机械设计的要求和设计的一般过程，机构结构 学、运动学和动力学的基础知识，机械零部件的工作能力和 设计准则，机械零件的强度理论，摩檫、磨损和润滑理论， 机械结构设计准则、方法以及零件材料选用等。另外，扼要 地介绍现代机械设计思想和方法。
1. Modern Machines and their Compositions
随着伺服驱动技术、检测传感技术、自动控制技术、信息 处理技术、材料及精密机械技术、系统总体技术等的飞速发展， 使传统机械在产品结构和生产系统结构等方面发生了质的变化， 形成了一个崭新的现代机械工业。现代机器已经成为一个以机 械技术为基础，以电子技术为核心的高新技术综合系统。
chapter 1 introduction
经过近80年的研究改进，汽车阻力系数从 0.8降至0.137，阻力减小为原来的1/5 。
3. How can the airplane fly?
Boeing 747 70.7×64.4× 19.41 (m)
An-225 84×88.4×18.1 (m) 600,000kg
395 000kg
机翼升力：来自下部还是上部？ 人们的直观印象是空气从下面冲击着鸟的翅膀 ，把鸟托在空中。19世纪初建立的流体力学环 量理论彻底改变了人们的传统观念。
20世纪30年代起，人们开始运用流体力学原理改进 汽车尾部形状，出现甲壳虫型，阻力系数降至0.6。
20世纪50－60年代改进为船型，阻力系数为0.45。
80年代经过风洞(wind tunnel experiments) 实验 系统研究后，又改进为鱼型，阻力系数为0.3 。
以后进一步改进为楔型，阻力系数为0.2。
MБайду номын сангаасst engineering problems are concerned with physical dimensions much larger than this limiting volume.
The elemental volume must be small enough in macroscope
g
Viscosity
Reconsider flow between fixed and moving parallel plates (Couette flow)
Note: u(0)=0 and u(h)=U i.e., satisfies noslip boundary condition
1. 2. 3. 4.
5.
Ruijie Reyee RG-RAP2260(E) 无线AP 硬件安装和参考指南说明书
Ruijie Reyee RG-RAP2260(E) Access Point Hardware Installation and Reference GuideCopyright statementRuijie Networks©2021Ruijie Networks reserves all copyrights of this document. Any reproduction, excerption, backup, modification, transmission, translation or commercial use of this document or any portion of this document, in any form or by any means, without the prior written consent of Ruijie Networks is prohibited.Exemption statementThis document is provided “as is”. The contents of th is document are subject to change without any notice. Please obtain the latest information through the Ruijie Networks website. Ruijie Networks endeavors to ensure content accuracy and will not shoulder any responsibility for losses and damages caused due to content omissions, inaccuracies or errors.·PrefaceThank you for using our products. This manual will guide you through the installation of the access point.ScopeIt is intended for the users who have some experience in installing and maintaining network hardware. At the same time, itis assumed that the users are already familiar with the related terms and concepts.Obtaining Technical Assistance●Ruijie Networks Website: https:///●Technical Support Website: https:///support●Case Portal: https://●Community: https://●Technical Support Email: *****************************●Skype: *****************************Related DocumentsDocuments DescriptionConfiguration Guide Describes network protocols and related mechanisms that supported by the product, with configuration examples.Command Reference Describes the related configuration commands, including command modes, parameter descriptions, usage guides, and related examples.Documentation ConventionsThe symbols used in this document are described as below:This symbol brings your attention to some helpful suggestions and references.This symbol means that you must be extremely careful not to do some things that may damage the device or cause data loss.·1 Product OverviewFeaturing leading 802.11a/b/g/n/ac/ax and MU-MIMO, Ruijie RG-RAP2260(E) supports 4 spatial streams and delivers upto 800Mbps at 2.4G and 2400Mbps at 5G. The overall dual-band performance speeds up to 3200Mbps per device, totallyeliminating Gigabit wireless bottlenecks. RG-RAP2260(E) adopts either local power supply or PoE power supply, andprovides two Ethernet ports, making it possible connect a camera or switch device to adapt to challenges in a wide varietyof deployment scenarios.1.1 Technical SpecificationsTable 1-1 RG-RAP2260(E) Technical SpecificationsModel RG-RAP2260(E)RF Four-stream and dual-bandTransmissionProtocolSupport concurrent 802.11ax, 802.11ac wave2/wave1, 802.11a/b/g/nOperating Bands 802.11b/g/n: 2.4 GHz to 2.4835 GHz802.11a/n/ac/ax: 5.150 GHz to 5.250 GHz, 5.250 GHz to 5.350 GHz, 5.470 GHz to 5.725 GHz, 5.725 GHz to 5.850 GHz (Country-specific)Antenna Array antenna (2.4G: 3dBi, 5G: 3dBi)Spatial Streams 2.4G: 4 x 4 MIMO5G: 4 x 4 MIMOMax Throughput 2.4G: up to 800 Mbps5G: up to 2400 MbpsUp to 3200 Mbps per APModulation OFDM: BPSK@6/9Mbps, QPSK@12/18Mbps, 16QAM@24Mbps, 64QAM@48/54Mbps DSSS:DBPSK@1Mbps,DQPSK@2Mbps,**********/11MbpsMIMO-OFDM: BPSK, QPSK, 16QAM , 64QAM, 256QAM and1024QAMOFDMAReceive Sensitivity 11b: -91dBm(1Mbps), -90dBm(5Mbps), -87dBm(11Mbps)11a/g: -89dBm(6Mbps), -82dBm(24Mbps), -78dBm(36Mbps), -72dBm(54Mbps) 11n: -85dBm(MCS0), -67dBm(MCS7)11ac: 20MHz: -85dBm(MCS0), -60dBm(MCS9)11ac: 40MHz: -82dBm(MCS0), -57dBm(MCS9)11ac: 80MHz: -79dBm(MCS0), -53dBm(MCS9)11ax: 80MHz: -79dBm(MCS0), -53dBm(MCS9),-52dBm(MCS11)Transmit Power ≤100mw(20dBm) (adjustable)Transmit PowerAdjustment1 dBmDimensions(W x D x H)220 mm x 220 mm x 35 mm (8.7 in. x 8.7 in. x 1.4 in.) (excluding brackets)Weight ≤ 1.05 kg (excluding brackets)Service Ports One 10/100/1000BASE-T Ethernet uplink port, one 10/100/2500BASE-T Ethernet uplink port,·LAN1/2.5G/PoE port is PoE+-capableManagement Ports N/ALED1 LED (green)Power Supply Adapter: DC 12 V/2.5 A (optional) PoE: IEEE 802.3at-compliant (PoE+). Power Consumption < 25.4WTemperatureOperating: 0°C to 40°C (32°F to 104°F) Storage: –40°C to 70°C (–40°F to 158°F) Humidity Operating: 5% to 95% RH (non-condensing) Storage: 5% to 95% RH (non-condensing) Installation Ceiling/wall mount Safety StandardsGB4943 IEC60950-1 EMC StandardsGB9254EN301 489 EN50155 EN50121Mechanical Vibration IEC61373Radio China Radio Transmission Equipment Type Approval Certificate EN300 328 EN301 893 MTBF> 400,000 HWeight refers to the weight of host.1.2 Product ImageThe AP provides two Ethernet ports (LAN1/2.5G/PoE port is PoE+-capable), and one power port for an external power supply.Figure 1-1 Appearance of RG-RAP2260(E)1.3 LED Indicator and ButtonLEDIndicatorand ButtonStateFrequency MeaningLED IndicatorOff N/A The AP is NOT receiving power. Blinking0.5HzNormal operation, but there is an alarm. Fast blinking10HzPossible cases:1. Restoring the factory default settings2. Upgrading the firmware3. Restoring the image file4. Initializing the deviceSolid greenN/ANormal operation. Reset ButtonPress for less than 2 seconds Restart the device.Press for more than 5 secondsRestore the factory settings.1.4 Power SourcesThe AP can be powered either with a power adapter or through Power over Ethernet (PoE).The power adapter is customer-supplied.To use a PoE device, make sure that it supports the IEEE 802.3at standard.1.5 Cooling SolutionThe AP features a fanless design.Leave sufficient space surrounding the AP when installing the AP to permit proper airflow for ventilation.2 Preparing for InstallationTo prevent device damage and physical injury, please read the safety recommendations carefully as described in this chapter.Recommendations do not cover all possible hazardous situations.2.1 InstallationThe AP must be installed indoors. To ensure normal operation, the installation site must meet the following requirements.●Install the AP in a well-ventilated environment. If it is installed in a closed room, make sure there is a good coolingsystem.●Make sure the site is sturdy enough to support the AP and its accessories.●Make sure the site has enough space for installing the AP and leave sufficient room around the AP for ventilation.●Do not expose the AP to high temperature, dust, or harmful gases.●Do not install the AP in an area prone to fire or explosions.●Keep the AP away from EMI sources such as large radar stations, radio stations, and substations.●Do not subject the AP to unstable voltage, vibration, and noises.●Keep the AP at least 500 meters away from the ocean and do not face it towards the sea breeze.●The installation site should be free from water including possible flooding, seepage, dripping, or condensation.●The installation site should be selected according to network planning and communications equipment features, andconsiderations such as climate, hydrology, geology, earthquake, electrical power, and transportation.Please follow the correct method described in the installation guide to install and remove the device.2.2 Movement●Avoid frequently moving the device.●Turn off all power supplies and unplug all power cables before you remove the device.2.3 EMI●Please observe local regulations and specifications when performing electrical operations. Relevant operators mustbe qualified.●Carefully check for any potential hazards in the working area such as damp/wet ground or floors.●Find the location of the emergency power supply switch in the room before installation. Cut off the power supply firstin case of an accident.●Be sure to make a careful check before shutting down the power supply.●Do not place the device in a damp/wet location. Do not let any liquid enter the chassis.·●Keep the AP far away from grounding or lightning protection devices for power equipment.●Keep the AP away from radio stations, radar stations, high-frequency high-current devices, and microwave ovens.Any nonstandard and inaccurate electrical operation can cause an accident such as fire or electric shock, thuscausing severe even fatal damages to humans and devices.Direct or indirect contact with a wet object (or your finger) on the high voltage and power line can be fatal.2.4 VentilationFor proper ventilation, leave sufficient space around the AP.2.5 Temperature and HumidityTo ensure the normal operation and equipment service life, maintain appropriate temperature and humidity levels in theequipment room. See Table 2-1. Improper room temperature and humidity can cause damage to the device.●High relative humidity may affect insulation materials, resulting in poor insulation and even electrical leakage.Sometimes it may lead to changes in the mechanical properties of materials and corrosion of metal parts.●Low relative humidity can dry and shrink insulation sheets and cause static electricity that can damage the circuitry.●High temperatures greatly reduce device reliability and shorten service life.Table 2-1 Required Temperature and Humidity for the RG-RAP2260(E)Temperature Relative Humidity0ºC to 40ºC (32°F to 104°F) 5% to 95%2.6 CleannessDust poses a serious threat to device operation. Dust on the surface of the device can be absorbed onto metal contactpoints by static electricity causing poor contact. Electrostatic absorption of dust occurs more easily when the relativehumidity is low, and might shorten the equipment service life and cause communication failures. Table 2-2 shows themaximum concentration and diameter of dust allowed in the equipment room.Table 2-2Maximum d iameter (μm)0.5 1 3 5Maximum concentration1.4×1077×1052.4×105 1.3×105(Particles/m3)The amount of salt, acids and sulfides in the air are also strictly limited for the equipment room. These substances canaccelerate metal corrosion and aging of some parts. Table 2-3 describes the limits of some hazardous gases such as SO2,H2S, NO2 and Cl2 in the equipment room.Table 2-3Gas Average (mg/m3) Maximum (mg/m3)·SO20.2 1.5H2S 0.006 0.03NO20.04 0.15NH30.05 0.15Cl20.01 0.32.7 Power Supply●DC power adapter:Input voltage: 12VRated current: 2.5A●PoE+ injector: IEEE 802.3at compliantTechnical Specifications of the DC ConnectorInner DiameterOuter DiameterInsertionDepthConductorImpedanceVoltage-enduranceImpedanceVoltage-endurance(Insulator andConductor)Polarity 2.10+/-0.05mm 5.50+/-0.05mm 9mm 5Ω100MΩ1000VInner pole:positiveOuter pole:negativeThe DC input power should be greater than the power actually consumed by the system.Use DC power adapters with specifications recommended by Ruijie.Please use Ruijie certified PoE injectors.Warning：802.3af or non-standard POE adapter may cause unknown issues. Please use Ruijie POE+ switch or 802.3at POE adapter as power supplier2.8 Installation ToolsCommon Tools Phillips (crosshead) screwdriver, copper and fiber cables, bolts, diagonal pliers, cable ties Special Tools Wire stripper, crimping pliers, RJ-45 crimping pliers, punch down toolMeter Multimeter, bit error rate tester (BERT)The tools listed above are customer supplied.2.9 Unpacking the Access PointPackage Contents·ItemsVerify that all parts are installed and debugged. ScrewsMounting bracketsProduct quick installation guide Packing listThe above listed items are for general situations, and contents may vary in the actual shipment. The purchasing ordershall prevail in any case. Please check each item carefully according to the packing list or purchasing order. If any item is damaged or missing, notify your sales representative.·3 Installing the Access PointThe RG-RAP2260(E) series must be fixed and installed indoors.Before installing the AP, make sure you have carefully read the requirements described in Chapter 2.3.1 Installation Flowchart3.2 Before You BeginBefore installing the AP, verify that:●The installation site provides sufficient ventilation for the AP.●The installation site meets temperature and humidity requirements.●The installation site is equipped with a proper power supply.●Network cables are in place.●The installation site meets all described requirements.●The custom AP meets customer requirements.3.3 PrecautionsTo avoid damage to the AP, observe the following safety precautions:●Do not power on the device during installation.●Install the device in a well-ventilated location.●Do not subject the device to high temperatures.●Keep away from high voltage cables.●Install the device indoors.●Do not expose the device in a thunderstorm or strong electric field.●Keep the device clean and dust-free.●Disconnect the device before cleaning it.●Do not wipe the device with a damp cloth.·●Do not wash the device with liquid.●Do not open the enclosure when the AP is working.●Fasten the device tightly.3.4 Installing the Access PointPlease install the AP in the method with a larger antenna coverage area.The antenna coverage area of ceiling-mounting is larger than that of wall-mounting indoors. Please select the formermethod.The installation process below is just for reference. The actual product prevails.●Ceiling Mount1. Attach the mounting bracket on the ceiling or wall, as shown in Figure 3-1.Figure 3-1 Attaching the Mounting Bracket on the Ceiling/Wall2. Connect the Ethernet cable to the LAN1 port. See Figure 3-2.Figure 3-2 Connecting the Ethernet Cable to the LAN1 Port3. Align the square feet on the rear of the AP over the mounting holes on the bracket. Slide the AP into the holes until itclicks into place, as shown in Figure 3-3.Figure 3-3 Fastening the AP·Install the Ethernet cables before mounting the AP on the bracket.The AP can be installed in any of four directions on the mounting bracket depending on how you route the Ethernetcable.The square feet should fit easily into the mounting slots. Do not forcibly push the AP into the slots.After installation, verify that the AP is securely fastened.3.5 Removing the Access PointHold the AP in your hands and push it upward and away from the bracket in the arrow direction, as shown in Figure 3-1.3.6 Connecting CablesConnect the UTP/STP to the LAN1 port on the AP. See Appendix A for the supported wiring for twisted pairs.Avoid bending the cable in a small radius close to the connector.Ruijie recommends that you do not use Ethernet cables with protective sleeves as they could make installation ofEthernet cables more difficult.3.7 Bundling CablesPrecautions●Make sure the cable bundles are neat and orderly.●Bend twisted pairs naturally or in a large radius close to the connector.●Do not over tighten a cable bundle as it may reduce cable life and performance.Bundling Steps1. Bundle the drop UTP/STP cables and route them to the LAN1/2.5G/PoE port.2. Attach the cables in the cable tray of the rack.3. Extend the cables under the AP and run in a straight line.·3.8 Checking after InstallationChecking the Cabinet●Make sure the external power supply matches the patch panel specifications for the cabinet.●After installation, make sure that the front and rear cabinet doors easily close.●Make sure the cabinet is stable and level.●Make sure the device and all cables are securely fastened in the rack.Checking Cable Connection●Make sure the UTP/STP cable matches the interface type.●Make sure cables are properly bundled.Checking the Power Supply●Make sure all power cables are properly connected and safe.●Make sure the AP is operational after powering on.4 System Debugging4.1 Setting up a Debugging EnvironmentUse a power adapter or PoE to power the AP.Setting up the Environment●Verify that the AP is properly connected to the power source.●Connect the AP to a wireless controller through a twisted pair cable.●When the AP is connected to a PC for debugging, verify that the PC and PoE switch are properly grounded.4.2 Powering up the AP4.2.1 Checking before power-up●Verify that the power supply is properly connected.●Verify that the input voltage matches the specification of the AP.4.2.2 Checking after power-up (recommended)After powering up, it is recommended that you check the following to ensure normal operation of the AP.●Check if any message is displayed on the Web-based configuration interface for the wireless controller.●Check if the LED works normally.5 Monitoring and Maintenance5.1 MonitoringLEDYou can observe the LED to monitor the AP in operation.5.1.1 Hardware MaintenanceIf the hardware is faulty, please contact our Technical Assistance Center (TAC) for help.6 Troubleshooting6.1 Troubleshooting Flowchart6.2 TroubleshootingLED does not light up after the AP is powered on1. If you use PoE power supply, verify that the power source is IEEE 802.11at compliant; then verify that the cable is properly connected.2. If you use a power adapter, verify that the power adapter is connected to an active power outlet; then verify that the power adapter works properly.Ethernet port is not working after the Ethernet port is connectedVerify that the device at the other end of the Ethernet cable is working properly. And then verify that the Ethernet cable is capable of providing the required data rate and is properly connected.Wireless client cannot find the AP1. First, follow the two steps above.·2. Verify that the AP is correctly configured.3. Adjust the angle of the antennas.4. Move the client device to adjust the distance between the client and the AP.·Hardware Installation and Reference Guide Appendix A Connectors and MediaAppendix A Connectors and Media1000BASE-T/100BASE-TX/10BASE-TThe 1000BASE-T/100BASE-TX/10BASE-T is a 10/100/1000 Mbps auto-negotiation port that supports auto MDI/MDIX. Compliant with IEEE 802.3ab, 1000BASE-T requires Category 5e 100-ohm UTP or STP (STP is recommended) with a maximum distance of 100 meters (328 feet).1000BASE-T requires all four pairs of wires be connected for data transmission, as shown in Figure A-1.Figure A-1 1000BASE-T Connection10BASE-T uses Category 3, 4, 5 100-ohm UTP/STP and 1000BASE-T uses Category 5 100-ohm UTP/STP for connections. Both support a maximum length of 100 meters. Table A-1 shows 100BASE-TX/10BASE-T pin assignments. Table A-1 100BASE-TX/10BASE-T Pin AssignmentsFigure A-2 shows wiring of straight-through and crossover cables for 100BASE-TX/10BASE-T.Figure A-2 100BASE-TX/10BASE-T Connection。
最新USP-1092-溶出度方法的开发和验证(中英文对照版)第一部分(1)
最新USP <1092>：溶出度方法的开发与验证(中英文对照)-开发部分2015-2020 USP通则-制剂专家委员会修订了USP 41溶出度方法的开发与验证<1092>通则，全文内容发表在PF46(6)，最后的评论限期为2019年1月31日。
主要修改部分如下：1.1.2节中溶解度测试和原料药在不同介质中的稳定性分为了两部分：1.2.1溶解度和1.2.2稳定性，这样可以讨论地更加清楚。
在修订部分给到了溶出方法数据库的参考文献，供使用者参考。
同时修订内容中提到了参考文献：溶解度测试通则<1236>，该通则在PF44(5)中被提出，是溶解度测试的指南。
2．1.3节中介质和体积的选择包含了USP对于漏槽条件新的描述。
修订部分中更加清楚的阐述了与体积的关系。
3．2.4.1节更新了“取样时间点部分”，以呼应最近的FDA指南更新的“取样时间点部分”。
4．2.5数据处理章节引用了一篇新的参考文献。
该文献中提到了一种情形：低溶解度的口服溶液在展示生物利用度时也许不合适。
文献提到了一种方法即用体外溶出曲线的方法初步评估体内溶出。
5．3.4分析方法章节加入了一个新图，用来描述在溶出样品分析时遇到的情形:溶出成分有全部或者部分进行了衍生化者降解。
6．5.3准确性和回收率章节中加入了延迟缓释制剂中原料药成分在酸性阶段测试时释放至酸性介质中，溶出后成分有降解发生的情况。
这种情形在验证时必须考虑到，需要提示的是，该情况在溶出<711>接受标准表3中没有被认识到。
7．在6.5.2延迟制剂章节更新部分，讨论了耐酸的延迟制剂在酸性阶段的测试结果，不仅要考虑溶出的原料药成分，降解物也需要考虑到。
限于译者水平有限，有不足的地方或者不正确的地方还请读者包涵，谢谢批评与指正。
<1092>THE DISSOLUTION PROCEDURE: DEVELOPMENT ANDVALIDATION<1092>溶出度试验的开发和验证INTRODUCTION前言Purpose目的The chapter provides a comprehensive approach covering items to consider for developing and validating dissolution procedures and the accompanying analytical procedures. It addresses the use of automation throughout the test and provides guidance and criteria for validation. It also addresses the treatment of the data generated and the interpretation of acceptance criteria for immediate- andmodified-release solid oral dosage forms.该通则提供了在溶出度方法开发和验证过程中，以及采用相应分析方法时需要考虑的因素。
1.2 - Statements, Properties, and Operations
Show What You Know
Write a program to display a text window and perform the following steps:
Set the top position of the text window to 100, and set its left position to 200. Write a statement that makes “Small Basic Programming” appear in the title bar of the text window. Set the top position of the cursor to 10 and left position to 20. Set the foreground color of the text to yellow. Display the sentence, “Welcome to the world of Small Basic programming.”
The Pause and Clear Operations
If you use the Pause operation, the computer waits for user input before returning the final output. If you use the Clear operation, the computer clears all text from the text window. Let’s write a program to better understand these operations.
Writing Text in the Text Window
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Learning Check
Identify each of the following as either chemical changes or physical changes of the substance. a. A match lights when struck. b. Air is squeezed by a pump and forced into o tire. c. A lump of gold is pounded into a large, thin sheet. d. Baking powder bubbles and gives off CO2 when it is moistened. e. A pan of water boils on the stove. f. Hydrogen sulfide gas causes silver to tarnish. Solution: physical changes: b, c, e chemical changes: a, d, f
physical properties
chemical properties
Physical Properties: can be observed or measured without
changing the composition of matter.
Chemical Properties: can be observed only when there is a Physical Change: are changes affecting the form of a
States of Matter
gas solid liquid
About 70% of Earth’s surface
States of Matter
gas
volatile
eg. alcohol gasoline
solid
melting freezing
liquid
Melting point = Freezing point
Chapter 1
Chemistry: The Science of Matter
Section 1.2 Properties and changes of Matter
Characteristic
Height Weight Age Sex Appearance Nationality Color of hair ……
chemical substance, but do not change the chemical composition of that substance.
changing in the composition of matter.
Chemical Change: can be observed only when there is a (Chemical reaction)changing in the composition of matter.
A person
Properties
?
Matter
Identifying Matter by Its Properties
Pure Iron(铁)
State（状态）: solid color: silvery-gray density: 7.86g/mL melting point: 1536°C boiling point: 2861°C physical properties
Chemical Reaction and Energy
Energy: is the capacity to do work
Chemical Reaction and Energy
Energy: is the capacity to do work
heat, light
give off heat energy
Can you give some examples foቤተ መጻሕፍቲ ባይዱ physical and chemical change ?
Learning Check
Identify each of the following as either chemical properties or physical properties of the substance. a. Aluminum bends easily. b. Magnesium burns in air. c. Gold jewelry is unaffected by perspiration（汗水）. d. Baking soda is a white powder. e. Fluorine is a highly reactive element. Solution: physical properties: a, d chemical properties: b, c, e
absorb heat energy
exothermic reactions
endothermic reactions
What are you able to do now!
Distinguish between physical and chemical properties. Contrast chemical and physical changes. Apply the law of conservation of matter to chemical changes.
Physical Properties: can be observed or measured without
Grind（研磨） bluestone（胆矾）
Fry egg
Iron rusts
Water is boiling
Electrolyze water
CaCO3 reacts with HCl
Boiling point = Condensation point
Atoms and Chemical Change
Law of conservation of mass: in a chemical change ,matter is neither created nor destroyed.
Rusts（铁锈） (oxidizes) in damp air dissolves quickly in dilute（稀释的） acids chemical properties
changing the composition of matter. can be observed only when there is a Chemical Properties: changing in the composition of matter. eg. : eg. : qualitative state, smile, taste, Nitrogen does not burn; odor, color Sodium reacts with water; …… High reactivity（高反 density, hardness, 应性）; quantitativ melting point, Instability（不稳定性） e boiling point, of a substance solubility in water …… ……