Tracing large-scale structure at high redshift with Lyman-alpha emitters the effect of pecu

小学上册英语第6单元期中试卷英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.What is the name of the famous character who is a yellow sponge?A. SpongeBob SquarePantsB. Patrick StarC. Squidward TentaclesD. Mr. Krabs2.What do you call a person who studies the environment?A. EcologistB. BiologistC. GeologistD. EnvironmentalistA3. A ______ (野花) can add color to a meadow.4. A ______ (刺猬) has a spiky exterior for defense.5.He is a firefighter, ______ (他是一名消防员), who responds to emergencies.6.The ancient Romans held _______ to celebrate victories. (游行)7. A ______ (城市花园) can beautify neighborhoods.8.We will have _____ (fun/work) at the park.9.What is the name of the cosmic event that marks the end of a star's life?A. SupernovaB. Black HoleC. White DwarfD. Neutron Starbustion reactions require fuel and _____.11.The chemical formula for potassium iodide is ______.12.In which month do we celebrate Christmas?What is the capital of France?A. LondonB. ParisC. Rome13.Hydrochloric acid is found in our ______.14.Mercury is the ______ planet from the Sun.15.She is ______ her toys in the box. (putting)16. A frog's color helps it stay ______ (隐蔽).17.The ____ is a noisy bird that mimics sounds.18.We are going to ___ a festival. (attend)19.My brother loves to __________ (参加) local sports events.20. (52) contains many islands. The ____21.She wears a _____ (红色的) dress.22.What do you call a book that tells real-life events?A. FictionB. NonfictionC. BiographyD. FantasyB23.My pet parrot can _________ (说话).24. A __________ is formed by the accumulation of organic matter.25.The ________ is the smallest continent.26.Which fruit is known for having seeds on the outside?A. BlueberryB. StrawberryC. RaspberryD. Blackberry27.We celebrate New Year in ______ (一月).28.The frog is _____ (jumping/sitting) on the lily pad.29.The chemical symbol for indium is ______.30.What do we call the process of animals sleeping through the winter?A. MigrationB. HibernationC. EstivationD. DormancyB Hibernation31.The city of Wellington is the capital of _______.32.The chemical symbol for sodium is _______.33.What do we call a person who studies the weather?A. MeteorologistB. ClimatologistC. GeographerD. Environmentalist34.I want to ___ a comic book. (read)35.What shape has three sides?A. SquareB. RectangleC. TriangleD. CircleC36. A kangaroo's strong hind legs enable it to travel long ________________ (距离).37.The city of Beijing is the capital of _______.38.What do we call a large-scale farming operation?A. PlantationB. RanchC. OrchardD. GardenA39.What sound does a cow make?A. MeowB. BarkC. MooD. QuackC40.My dog loves to play with a ______ (球) in the park.41.I love to ______ (分享) my toys.42.Which month has Halloween?A. SeptemberB. OctoberC. NovemberD. December43.In winter, some plants _______ their leaves.44.What do you call a large area of rock and soil that is elevated?A. HillB. MountainC. PlateauD. CliffB45.I go to the library to _____ (read/study).46.What is the chemical formula for table salt?A. NaClB. KClC. MgCl2D. CaCl247.The __________ (历史的探索) continues to reveal new truths.48. A _______ (鳄鱼) has sharp teeth.49.The ______ (植物的生长) can be influenced by climate change.50.My cousin is learning to _______ (动词). 她对这个很 _______ (形容词).51.The ______ helps with the sense of smell.52.The main gas that contributes to the greenhouse effect is __________.53.She has a ___ (beautiful/ugly) dress.54.The Earth's tilt affects the changing of the ______.55.We have a ______ in our garden. (fountain)56.The first president of the United States was _______ (George Washington).57.I enjoy ______ (画画) in my sketchbook.58. A _____ (园艺书籍) can provide useful tips for gardeners.59.I saw a rainbow after the ______ (雨). It was very ______ (绚丽).60.The _____ (teacher/student) is helpful.61.I enjoy going outside when it’s __________. (阳光明媚的)62.How many days are in a week?A. FiveB. SixC. SevenD. Eight63. A ______ is a summary of experimental procedures.64.I have a special ________ that makes me happy.65.I saw a _______ (bird/fish) in the tree.66.The city of Istanbul is located in ________ (伊斯坦布尔位于________).67. A __________ (无机化合物) does not primarily contain carbon.68.What is the capital of Australia?A. SydneyB. MelbourneC. CanberraD. BrisbaneC69.What is 5 x 3?A. 10B. 15C. 20D. 2570.What is the largest ocean on Earth?A. AtlanticB. IndianC. ArcticD. Pacific71.Which instrument is used to measure temperature?A. BarometerB. ThermometerC. RulerD. ClockB72.I enjoy _____ (reading/playing) books at home.73.The __________ (历史的影响) can create change.74.The ice cream is ________ cold.75.I saw a _____ (鳄鱼) at the zoo.76.I love to watch ________ (科幻电影) in the theater.77.What do we call the science of classifying living things?A. BotanyB. TaxonomyC. ZoologyD. AnatomyB Taxonomy78.What do you call a large, flightless bird?A. EagleB. OstrichC. SparrowD. FalconB79.My mom makes _____ for breakfast. (pancakes)80.What is the name of the famous American singer known for her powerful voice?A. Whitney HoustonB. Mariah CareyC. Aretha FranklinD. AdeleA81.We have a ______ (快乐的) family dinner every Sunday.82.I like to ________ (network) with professionals.83.________ (植物迁徙) occurs naturally.84.Many animals hibernate during the ______.85.The process by which plants make their food is called _______.86.I write stories in my ______.87. A ______ (青蛙) can jump very high and far.88.The _____ (兔子) is known for its long ears.89.What is the name of the famous tower in Pisa, Italy?A. Tower of LondonB. Leaning Tower of PisaC. Eiffel TowerD. CN Tower90.In the garden, I saw a _______ (小鸟) singing happily on a branch.91.What do we call the person who leads a country?A. PresidentB. Prime MinisterC. MonarchD. All of the above92.My uncle is very _______ (形容词) about his job. 他总是 _______ (动词).93. A compound that can act as both an acid and a base is called an ______.94.I like to _____ (参观) historical sites.95.The _______ (Fourteenth Amendment) grants citizenship to all born in the US.96.The process of making biodiesel involves transesterification of _______ oils.97.What do we call the art of folding paper?A. PaintingB. OrigamiC. SculptureD. Drawing98.The __________ is a region known for its diplomatic relations.99.The ancient Egyptians invented _______ for writing. (象形文字)100. A _______ is a type of mixture where the components are not uniformly mixed.。

Evolution Unit 5 Overview - MARRIC5概述-马立克进化单元Name:____________________________________ Date:_____________Period:_____ Evolution Unit 5 – OverviewSchedule – February 11, 2009 through March 27, 2009; Unit Exam Tuesday 3/23/09Unit 5. Evolution Key Standards (2nd Semester)5a. The frequency of an allele in a gene pool of a populationdepends on many factors and may be stable or unstable over time.Students will apply how natural selection affects the characteristics of an organism and how mutations are maintained within a gene pool. (7a, 7b, 7c) Key Elements:1. Define the following concepts: natural selection, mutation, gene pool2. Describe the process of natural selection.3. Give an example of natural selection in nature.4. Explain how natural selection affects the characteristics of an organism.5. Explain how a mutation is formed.6. Discuss how a mutation is maintained within a gene pool.5b. The frequency of an allele in a gene pool of a populationdepends on many factors and may be stable or unstable over time. Evolution is the result of genetic changes that occur in constantlychanging environments. Students will describe how greater variationwithin a species may lead to greater survival of that species. (7d, 8b) Key Elements:1. Define variation, species.2. Explain how variation affects a species survival.3. Give a realistic example of how variation in a species has leadto its greater survival.5c. Evolution is the result of genetic changes that occur in constantly changing environments. Students will evaluate the effects of genetic drift and geographic isolation on a species. (8c, 8d) Key Elements:1. Define the following: genetic drift, gene pool, geographic isolation, and species2. Evaluate how genetic drift will affect a species, its gene pool, and its survival.3. Evaluate how geographic isolation will affect a species, its gene pool, and its survival. 5d. Evolution is the result of genetic changes that occur in constantly changing environments. Students will identify that analysis of fossil, DNA, and anatomical evidence supports evolution. (8e, 8f) Key Elements:1. Define the following: fossil, DNA, anatomical evidence, evolution, homologous structures, andanalogous structures.Evolution Unit Overview 12. Describe how fossil evidence supports evolution.3. Describe how DNA evidence supports evolution.4. Describe how anatomical evidence supports evolution.5. Give a realistic example of how all of the following support evolution: fossil evidence, DNA,and anatomical evidence.Note: The abbreviation CCS stands for California Content Standards referenced below.California Standards Evolution7. The frequency of an allele in a gene pool of a population depends on many factors and may be stable or unstable over time. As a basis for understanding this concept:a) Students know why natural selection acts on the phenotype rather than the genotype of anorganism.b) Students know why alleles that are lethal in a homozygous individual may be carried in aheterozygote and thus maintained in a gene pool.c) Students know new mutations are constantly being generated in a gene pool. d) Students know variation within a species increases the likelihood that at least some members ofa species will survive under changed environmental conditions.8. Evolution is the result of genetic changes that occur in constantly changing environments. As a basis for understanding this concept:a) Students know how natural selection determines the differential survival of groups oforganisms.b) Students know a great diversity of species increases the chance that at least some organismssurvive major changes in the environment.c) Students know the effects of genetic drift on the diversity of organisms in a population. d) Students know reproductive or geographic isolation affects speciation.e) Students know how to analyze fossil evidence with regard to biological diversity, episodicspeciation, and mass extinction.Textbook – Chapters 14 History of Life (pg 390 – 415) 15 Evolution (pg 416-449).Class Website – /teaching;Resources -, May 1998Tentative ScheduleWeek 1: 2/16 - 2/20 –President’s Day Holiday 2/16 Chapter 14 History of Life (due 2/23),Week 2: 2/23 - 2/27 –Unit 5 Quiz 1, Chapter 15 Evolutionary Processes (due on 3/5)Week 3: 3/2 - 3/6 – Unit 5 Quiz 2, Chapter 15 Evolution and Natural SelectionWeek 4: 3/9 - 3/13 – Unit 5 Quiz 3, Chapter 17 Classification and Review for ExamWeek 5: 3/16 - 3/20 – Breeding Bunnies and Molecular Clocks and Review for ExamWeek 6: 3/23 – 3/27 – Unit 5 Exam 3/24/00; Portfolio preparation Evolution Unit Overview 2"In the broadest sense, evolution is merelychange, and so is all-pervasive; galaxies,languages, and political systems all evolve.Biological evolution ... is change in theproperties of populations of organisms thattranscend the lifetime of a single individual. 1The ontogeny of an individual is notconsidered evolution; individual organisms donot evolve. The changes in populations thatare considered evolutionary are those thatare inheritable via the genetic material fromone generation to the next. Biologicalevolution may be slight or substantial; itembraces everything from slight changes inthe proportion of different alleles within apopulation (such as those determining bloodtypes) to the successive alterations that led 2from the earliest protoorganism to snails,bees, giraffes, and dandelions." Douglas J.Futuyma in Evolutionary BiologyWhat changes in evolution? Actually whatchanges is the frequency of an allele. Thefrequency of an allele in the gene pool of apopulation is how often an allele occurs inthe genotypes of individuals of the samespecies that are in the same area - thesame population. How often the alleleoccurs depends on lots of factors such as 1) what the allele codesfor - is it a critical trait for survival and 2) is the allele a dominant or a recessive allele. These factors determine whether the allele will be present for a long time or a short time. Naturalselection acts on population by changing the frequency of different alleles. If an allele is harmful, it will be eliminated from the population or reduced in its frequency because those individuals in the population exhibiting the trait will not survive. This leads to a fine difference between genotype and phenotype. Remember genotype is the kinds of genes an individual has and phenotype is its observable traits. It is the observable traits that are selected for or against resulting in increased allele frequency or reduced allele frequency, respectively. Since we are also considering genotypes, recall that the three ways that mutations happen most often are changes in the DNA (deoxyribonucleic acid) sequence due to insertions, deletions, or substitutions. It is very easy to get overly concerned about evolution if the focus is on human evolution. If instead the focus is on the mechanisms of how organisms change over time, a lot of emotional distress can be avoided. Being a Roman Catholic and believing that God created the Universe does not necessarily conflict with evolutionary theory. Evolution can be thought of as an accumulation of changes that occur within a population resulting from genetic and environmental changes. Within a population oforganisms of the same species there are differences between the individuals (variation). A species is a group of individuals that can interbreed and produce fertile offspring (offspring that can reproduce). The greater the variation between individuals the greater the likelihood that the species will survive if the environment changes.1 Ontogeny: the development of an individual from the moment the egg is fertilized up till adulthood.2 Protoorganisms: bacteria.Evolution Unit Overview 3Since the Earth was created, many environmental changes haveoccurred and some species have become extinct and others have apparently changed into different species. If an environment changes too much and there is not enough variation within the population, few if any individuals will survive the change, resulting in the species becoming extinct. But if there is sufficient variation so that some “weirdoes” can survive, then those will be the ones that can reproduce and their characteristic genes transmitted to the next generation. If there were a few before the change, then after the change they will be the majority apparently evolving into another species. Looking at fossils (mineralized remains of organisms) similarities can be observed. Paleontologists and evolutionary biologists have developed relationships between existing and extinct species by tracing anatomical and genetic similarities and differences.Besides mutations and large scale environmental changes, more minor changes can result in speciation. Speciation is the formation of a newspecies or group of organisms that can no longer interbreed with an original species population. These organisms no longer interbreed because their characteristics (either biological or behavioral) have become too different. This can happen randomly and by geographicisolation of a species. A random change in the kinds of genes in a population is called genetic drift. When populations of interbreeding individuals of the same species are large, the the allele frequency of each successive population is expected to vary little from the frequency of its parent population unless there are adaptive advantages associated with the alleles. But with a small breeding population (a group separated by geography), a change in even one individual can cause a disproportionately greater change in the population’s gene pool. Thereforesmall populations are more subject to genetic drift effects thanlarge populations. A situation exists when large populations are quickly reduced. This population reduction is called a population bottleneck. Like a bottleneck that is narrower than the bottle genetic variation is reduced. The reduced variation results in sudden changes in the allele frequency within the gene pool, and of the population’s characteristics. These type of changes are not gradual and called punctuated because sudden and drastic changes can occur. So evolutionary changes are not always slow (gradualism) or always rapid (punctuated equilibrium).Vocabulary1.Adaptation______________________________________________________________ ______________________________________________________________________ ____2. Analogousstructures________________________________________________________ ____________________________________________________________________ ____3. Anatomicalevidence_________________________________________________________4. ArtificialSelection__________________________________________________________ ____________________________________________________________________ ____5. DNA____________________________________________________________________6. Evolution_________________________________________________________________7.Embryology______________________________________________________________ _____________________________________________________________________ ____Evolution Unit Overview 48.Era_____________________________________________________________________ 9.Extinct_________________________________________________________________ __ 10. Fitness_________________________________________________________________ ____________________________________________________________________ ____ 11. Fossil___________________________________________________________________ ____________________________________________________________________ ____ 12. Foundereffect_____________________________________________________________ ____________________________________________________________________ ____ 13. Gene Pool________________________________________________________________ 14. GeneticDrift______________________________________________________________ ____________________________________________________________________ ____ 15. GeographicIsolation_________________________________________________________ 16. Geologic TimeScale_________________________________________________________ 17.Gradualism______________________________________________________________ ______________________________________________________________________ ____ 18.Interbreeding___________________________________________________________ __ 19. Homologousstructures_______________________________________________________ ____________________________________________________________________ ____ 20. MassExtinction____________________________________________________________ 21.Mimicry_________________________________________________________________ _ 22.Mutation________________________________________________________________ _ 23. Natural selection___________________________________________________________ ____________________________________________________________________ ____ 24.Paleontology____________________________________________________________ ___ 25.Period__________________________________________________________________ _ 26. Phenotype________________________________________________________________ 27.Population______________________________________________________________ _______________________________________________________________________ ____ Evolution Unit Overview 528. Punctuatedequilibrium_______________________________________________________ ____________________________________________________________________ ____ 29. Radioactive (radiometric)dating____________________________________________________________________________________________________________________ ____ 30. Relativedating_____________________________________________________________ ____________________________________________________________________ ____ 31. Reproductiveisolation________________________________________________________ ____________________________________________________________________ ____ 32. Survival of thefitness_______________________________________________________ ____________________________________________________________________ ____ 33.Speciation______________________________________________________________ ______________________________________________________________________ ____ 34.Species_________________________________________________________________ _ 35.Theory__________________________________________________________________ _ 36. Vestigial Structure(organ)____________________________________________________ ____________________________________________________________________ ____ 37.Variation_______________________________________________________________ __ 38.Darwin__________________________________________________________________ _ 39.Diversity_______________________________________________________________ __ 40. Indexfossil_______________________________________________________________ ____________________________________________________________________ ____ 41.Niche___________________________________________________________________ _ 42.Pesticide_______________________________________________________________ __ 43.Resistant_______________________________________________________________ __ 44.Variation_______________________________________________________________ __ 45. GalapagosIslands___________________________________________________________ Steps of Natural SelectionEvolution Unit Overview 6Evolution Unit Study Guide1. Evolution can be defined as any change in the relative frequency of alleles in the gene pool of a_____________________2. Differences between the members of a population will most likely be passed onto futuregenerations if they are3. Mutations that are lethal in homozygous individuals can survivein a population by being carriedbyA population of land snails colonized a field of yellow grass. At first, thepopulation contained two types of snails, one with brown bands on their shellsand another with yellow bands on their shells, as shown in thefigure below.After 10 years, most of the snails had shells with yellow bands.4. What process most likely led to an increase in the number ofsnails with yellow bands?5. What is the most likely reason that there are more yellow-banded snails present in thegrassland?A field of crops was sprayed with pesticides to control a population of insects that was eating the crop. Only 1% of the insects survived. The same amount and type of pesticide was sprayed on the field each year for the next 4 years. The graph below shows the percentage of insects that survived each year after the pesticide was used.6. Why was the pesticide less effective each year in its ability to control the target population ofinsects?7. change over evolutionary time.Evolution Unit Overview 78. In a species of plant, the sudden appearance of one plant with a different leaf structure wouldmost likely be the result of9. What would cause a mutation?10. In carrier pigeons there is a rare inherited condition that causes the death of the chicksbefore hatching. In order for this disease to be passed from generation to generation theremust be parent birds that11. Describe natural selection.12. The idea that evolution takes place at a continuous but very slow rate is knows as ______13. The idea that evolution takes place at one point in time, followed by a long period withoutchange is14. A genetic change will be maintained in a population if the change15. According to Darwin’s theory of natural selection, individuals who survive are the ones bestadapted for their environment. Their survival is due to the____________________________________________________________________ _16. When mountain lions prey on a herd of deer, some deer are killed and some escape. Which partof Darwin’s concept of natural selection might be used to describe this situation?17. A change in a sequence of DNA is called a18. Natural selection acts directly on19. If a mutation introduces a new skin color in a lizard population, what factor might determinewhether the frequency of the new allele will increase?_____________________________________________________________________20. genetic diversity provides a species with a higher probabilityof survivingchanges to its environment.21. The difference in the fur color of the individual species in a population is described as___________________________22. Two animals of different species would not be able to23. Spraying DDT to kill mosquitoes became less effective each year the pesticide was used. Thisdecrease in the effectiveness was probably caused by the fact that ______24. When penicillin was first introduced it was very effective in destroying most of the bacteriathat cause gonorrhea. Today, certain varieties of this bacterium are resistant to penicillin.Explain the presence of these penicillin resistant bacteria.Evolution Unit Overview 825. Although similar in many respects, two species of organisms exhibit differences that makeeach well adapted to the environment in which it lives. The process of change that may accountfor these differences is26.27. A random change in gene frequency in a small population is called28. Genetic drift is most likely to effect29. Geographic and reproductive isolation can result in30. A species of finch (a type of bird) has been studied on one of the geographically isolatedGalapagos Islands for many years. Since the island is small, the lineage of every bird forseveral generations is known. This allows a family tree of each bird to be developed. Somefamily groups have survived and others have died out. The groupsthat survive probably have31. A single species of squirrel evolved over time into two species, each on opposite sides of theGrand Canyon. This change was most likely due to32. All the genes of all members of a particular population make up the population’s ___________.33. Describe a gene pool.34. In genetic drift, allele frequencies change because of35. Genetic drift tends to occur in populations thatEvolution Unit Overview 936. A small population of chimpanzees lives in a habitat that undergoes no change for a long period.How will genetic drift probably affect this population?________________37. The separation of populations by barriers such as rivers, mountains, or bodies of water is called38. The geographic isolation of two populations of a species tends to increase differences betweentheir gene pools because it39. What kind of animal would be best adapted to survive extreme change in temperature?Comparisons are made between two different organisms by finding the place where the two lines intersect. The number where the columns and rows intersect shows how many amino acids are different in the cytochrome c of both organisms. For example, the number of amino acids that are different when comparing a rabbit's cytochrome c with a tuna's cytochrome c is 17. The larger thenumber, the greater the difference in the structure of the cytochrome c molecules of the twoorganisms.40. According to the table, which pair of organisms is least closely related?41. According to the table, which pair of organisms is most closely related?42. In a certain area of undisturbed layers of rock, fossils of horseshoe crabs may be found in theupper layer, and a lower layer contains fossils of trilobites. Trilobites are extinct aquaticarthropods resembling modern horseshoe crabs. This information suggests thatEvolution Unit Overview 1043. In the early stages of development, the embryos of dogs, pigs, and humans resemble eachother. This observation suggests that these animals may have44. An example of a structure that would be homologous to a birdwing would be a45. Fossil trees are petrified when the wood is replaced with46. The long, slow process of change in species over time is47. In humans, the pelvis and femur, or thigh bone, are involved in walking. In whales, the pelvisand femur shown in the figure above are48. Modern sea star larvae resemble some primitive vertebrate larvae. This similarity may suggestthat primitive vertebrates49. The number and location of bones of many fossil vertebrates are similar to those in livingvertebrates. Most biologists would probably explain this fact on the basis of __________________________________________________________________________ ___50. Individuals within a population of rabbits have different colors of fur as shown in the diagrambelow. The difference in the fur color of the individual rabbits is described as_____________________.51. What are three types of mutation?Sunny says Hi and Good Luck on your studies. Bunny out.Evolution Unit Overview 11。

第 39 卷第 3 期2023 年6 月结构工程师Structural Engineers Vol. 39 ， No. 3Jun. 2023考虑混凝土徐变收缩的超高层偏心核心筒-框架结构水平变形和结构内力分析鲁正1，*周映旻1王远航2王超3张富文3（1.同济大学结构防灾减灾工程系，上海 200092； 2.中建三局集团第一建设有限责任公司，武汉 266100；3.上海市建筑科学研究院有限公司，上海 200032）摘要核心筒偏置的框架-核心筒结构在平面上不对称，可能在水平方向产生较大的不利变形。

采用混凝土徐变收缩B3模型，在ETABS中对某偏心核心筒-框架结构进行施工分析，计算了结构在不同时期的水平变形，并分析了水平变形对结构内力的影响。

计算中考虑了钢管混凝土柱中钢管的环箍效应，以及钢管与混凝土的应力重分布、施工工序等因素。

计算结果表明，偏心核心筒-框架结构的水平变形沿结构高度呈“中间大、两头小”分布。

研究结果显示徐变和收缩引起的水平变形随时间明显增加，部分幅值在后期大于弹性变形；合理规划施工顺序可有效降低结构构件内力。

通过与实测数据的对比，验证了所用模型的准确性。

关键词高层结构，水平变形，徐变收缩，施工分析Analysis of Horizontal Deformation and Internal Force of Super High-Rise Frame-Eccentrical Core Tube StructureConsidering Creep and Shrinkage of ConcreteLU　Zheng1，*ZHOU　Yingmin1WANG　Yuanhang2WANG　Chao3ZHANG　Fuwen3（1.Department of Disaster Mitigation for Structures，Tongji University， Shanghai 200092， China；2.The First Construction Co.，Ltd.， of China Construction Third Engineering Bureau Group， Wuhan 266100， China；3.Shanghai Research Institute of Building Sciences Co.，Ltd.， Shanghai 200032， China）Abstract The frame-eccentrical core tube structure is asymmetric in plane and may produce large adverse deformation in horizontal direction. The B3 model of concrete is used to analyze the construction of a frame-eccentrical core tube structure in ETABS. The structural horizontal deformation in different periods is calculated and the influence of horizontal deformation on the internal force of the structure is analyzed. The hoop effect of steel tube in CFST column，the stress redistribution between steel tube and concrete and the construction sequences are considered. The calculation results show that the horizontal deformation of the eccentric core-frame structure is large in the middle and small at both ends along the structural height. The results show that the horizontal deformation caused by creep and shrinkage increases obviously with time， and their amplitude will be larger than the elastic deformation in partial components in the later stage； besides， the results also show that reasonable planning for construction sequence can effectively alleviate the internal force of structural members. The accuracy of the model is verified by comparing with the measured data.收稿日期：2022-05-20基金项目：国家重点研发项目（2020YFB1901402），上海市优秀学术带头人计划（20XD1423900），中央高校基本科研业务费专项资金资助（11080）* 联系作者：鲁正（1982-），男，汉族，浙江上虞人，工学博士，教授，主要从事高层建筑抗震性能研究。

易错点17 阅读理解主旨大意题目录01 易错陷阱（3大陷阱）02 举一反三【易错点提醒一】标题类易混易错点【易错点提醒二】段落大意类易混易错点【易错点提醒三】文章大意类易混易错点03 易错题通关养成良好的答题习惯，是决定高考英语成败的决定性因素之一。

做题前，要认真阅读题目要求、题干和选项，并对答案内容作出合理预测;答题时，切忌跟着感觉走，最好按照题目序号来做，不会的或存在疑问的，要做好标记，要善于发现，找到题目的题眼所在，规范答题，书写工整;答题完毕时，要认真检查，查漏补缺，纠正错误。

易错陷阱1：标题类易混易错点。

【分析】标题类是对中心思想的加工和提炼，可以是单词、短语、也可以是句子。

她的特点是短小精悍，多为短语；涵盖性、精确性强；不能随意改变语言表达的程度和色彩。

如果是短语类选项，考生容易混淆重点，此时应当先划出选项的关键词。

此类题和文章的中心主题句有很大关系。

中心主题句一般出现在第一段，有时第一段也可能引出话题，此时应当重点关注第二段和最后一段，看看是否会出现首尾呼应。

易错陷阱2：段落大意类易混易错点。

【分析】每个段落都有一个中心思想，通常会在段落的第一句或最后一句体现，这就是段落主题句。

如果没有明显的主题句时，应当根据段落内容概括处段落大意。

有时考生还会找错文章对应位置，盲目选词文中相同的词句，而出现文不对题的现象。

易错陷阱3：文章大意类易混易错点。

【分析】确定文章主旨的方法是：先看首尾段或各段开头再看全文找主题句，若无明显主题句，就通过关键词句来概括。

如，议论文中寻找表达作者观点态度的词语，记叙文中寻找概括情节和中心的动词或反映人物特点的形容词。

文中出现不同观点时，要牢记作者的观点彩色体现全文中心的。

此时，要注意转折词，如：but, however, yet, in spite of, on the contrary等。

【易错点提醒一】标题类易混易错点【例1】（浙江省义乌五校2023-2024学年高三联考试题）The scientist’s job is to figure out how the world works, to “torture (拷问)” Nature to reveal her secrets, as the 17th century philosopher Francis Bacon described it. But who are these people in the lab coats (or sports jackets, or T-shirts and jeans) and how do they work? It turns out that there is a good deal of mystery surrounding the mystery-solvers.“One of the greatest mysteries is the question of what it is about human beings — brains, education, culture etc. that makes them capable of doing science at all,” said Colin Allen, a cognitive scientist at Indiana University.Two vital ingredients seem to be necessary to make a scientist: the curiosity to seek out mysteries and the creativity to solve them. “Scientists exhibit a heightened level of curiosity,” reads a 2007 report on scientific creativity. “They go further and deeper into basic questions showing a passion for knowledge for its own sake.” Max Planck, one of the fathers of quantum physics, once said, the scientist “must have a vivid and intuitive imagination, for new ideas are not generated by deduction (推论), but by an artistically creative imagination.”......ong as our best technology for seeing inside the brain requires subjects to lie nearly motionless while surrounded by a giant magnet, we’re only going to make limited pro gress on these questions,” Allen said.What is a suitable title for the text?A．Who Are The Mystery-solversB．Scientists Are Not Born But MadeC．Great Mystery: What Makes A ScientistD．Solving Mysteries: Inside A Scientist's Mind【答案】C【解析】文章标题。

JOURNAL OF HYDRAULIC ENGINEERINGVol.47No.8，2016（Monthly）C O N TEN TSOptimal operation of flood control for cascade reservoirs based on Parallel Chaotic Quantum Particle Swarm Optimization……ZOU Qiang WANG Xuemin LI Anqiang HE Xiaocong LUO Bin（967）Slope stability analysis by considering rainfall infiltration in multi-layered unsaturated soils…………SHI Zhenming SHEN Danyi PENG Ming ZHANG Lulu ZHANG Fawang ZHENG Xiaozhan（977）Mesoscale numerical analysis on moisture transportin in cracked concrete subjected to drying-wetting cycles………………………………………………………………WANG Licheng BAO Jiuwen（986）Characteristics of Nitrate-N losses through runoff and hydrological tracing in subtropical agricultural catchments……………………………………………………………………………………………………………WANG Rui TANG Jialiang ZHANG Xifeng SHEN Dong ZHAI Longbo ZHU Bo（996）Contribution of hydrological and biological processes to nutrient retentionin an agricultural headwater stream predominated by Phragmites australis…………………………………………………………………………………LI Ruzhong CAO Jingcheng HUANG Qingfei YIN Xiaoxi YAN Xiaosan（1005）Changes in the turbulent characteristics for sediment bed coated by biofilm…………………………………………………CHENG Wei FANG Hongwei HUANG Lei LAI Haojie HE Guojian（1017）Research on river health assessment based on different biological assessmblages………………………………………………………………LI Yanli LI Yanfen ZHAO Li XU Zongxue SUN Wei（1025）Mechanism of the intermittent motion of two-phase debris flows head and the energy character……………………………………………………………………LÜLiqun WANG Zhaoyin CUI Peng（1035）Investigation on hydraulic transients in tailrace tunnel with air inlet and release from the vent………………………………………………………………………………YU Xiaodong ZHANG Jian（1045）Investigating the circle pipe’s roughness with the fractal geometry theory and the practical application ……………………………………………………………………………………ZHANG Landing（1054）Fracture toughness of concrete after carbonation and wet-dry cycle of sulfate solution……………………………………………………ZHANG Tingyi WANG Zili ZHENG Guanghe ZHU Haitang（1062）Bearing mechanism of reinforced concrete penstock with steel liner considering friction-contact behav⁃ior…………………………………………SU Kai ZHANG Wei WU Hegao SHI Changzheng（1070）Discrete and continuous coupling numerical simulation of the impact loading……………………………………………………………………………………JIA Mincai CHEN Chun WU Shaohai（1079）Finite-element simulation and experiment on polymer directional fracturing and grouting for dykes and dams………………………SHI Mingsheng WANG Fuming LIU Heng GUO Chengchao（1087）985 976 99510161016 1024 1034 1044 1053 1061 1069 1078 1086 1092 Page Number in This File水利学报SHUILI XUEBAO 第47卷2016年第8期（月刊）目次［期刊基本参数］CN11-1882/TV *1956*m *A4*128*zh *P *￥30.00*1200*14*2016-08基于并行混沌量子粒子群算法的梯级水库群防洪优化调度研究………………………………………………………………………………………………邹强王学敏李安强何小聪罗斌（967）考虑多层非饱和土降雨入渗的边坡稳定性分析………………………………………………………………………………………………………石振明沈丹祎彭铭张璐璐张发旺郑小站（977）干湿交替下开裂混凝土中水分传输的细观数值分析…………………………王立成鲍玖文（986）亚热带农业小流域暴雨过程硝态氮迁移特征及水文示踪研究………………………………………………………………………………………王芮唐家良章熙锋申东翟龙波朱波（996）芦苇占优势农田溪流营养盐滞留的水文和生物贡献分析………………………………………………………………………………………………………李如忠曹竟成黄青飞殷晓曦严小三（1005）生物膜泥沙床面对水体紊动影响的实验研究…程伟方红卫黄磊赖豪杰何国建（1017）基于不同生物类群的河流健康评价研究………李艳利李艳粉赵丽徐宗学孙伟（1025）两相泥石流龙头的非恒定运动过程及能量特征……………………吕立群王兆印崔鹏（1035）尾水隧洞通气孔进排气瞬态过程研究…………………………………………俞晓东张健（1045）用分形几何理论研究圆管糙率及其实用意义……………………………………………张兰丁（1054）碳化与硫酸盐溶液干湿循环后混凝土断裂韧度…………张廷毅汪自力郑光和朱海堂（1062）考虑摩擦接触特性的钢衬钢筋混凝土管道承载机理研究…………………………………………………………………………………………………………………苏凯张伟伍鹤皋石长征（1070）冲击荷载作用的离散-连续耦合数值模拟……………………………贾敏才陈纯吴邵海（1079）堤坝高聚物定向劈裂注浆试验与有限元模拟……………石明生王复明刘恒郭成超（1087）EDITORIAL BOARDHONORARY PRESIDENTSSUO Lisheng HU Siyi LIU NinCONSULTANTSLU Youmei ZHU Erming GAO Anze ZHANG Zezhen CHEN Bingxin GAO JizhangPRESIDENTKUANG Shang-fuVICE PRESIDENTSWU Hongwei YU Qiyang JIA Jinsheng YANG XiaodongMEMBERSCAI Xuming（U.S.A）CAI Yuebo Chandra Madramootoo（Canada）CHEN Jin CHEN Houqun CHEN Qiuwen CHEN Minjian CHEN Shengshui CHEN Zuyu CHENG Guoyin CHENG Xiaotao DENG Jiaquan Desmond Walling（UK）DU Leigong FANG Hongwei FENG Ping FENG Shaoyuan FNEG Shurong GAN Hong GAO Zhanyi GU Hong GUO Jun GUO Qizhong（U.S.A）GUO Shenglian HAN Qiwei HE Jianbing HU Chunhong HUAI Wenxin HUANG Jiesheng HUANG Qiang HU Zuoliang Hyo-Seop Woo（Korea）JIA Jinsheng James Yang（Sweden）JIANG Naiqian JIE Yuxin JIN Juliang KANG Shaozhong KONG Xianjing KUANG Shangfu LI Jiren LI Jia LI Jiusheng LI Wanhong LI Yun LI Yuanyuan LI Zantang LIAN Jijian Xu Liang（U.S.A）LIU Handong LIU Xiaoyan LIU Yulong LIU Zhiping LU Jinyou LU Wenxi MA Hongqi MA Jianhua NI Jinren NIU Xinqiang Norihisa Matsumoto（Japan）PENG Caide QIN Boqiang Roger Falconer（UK）SHEN Zhenzhong SHU Longcang TIAN Bin WANG Fujun WANG Guangqian WANG Hao WANG Lizhong WANG Renkun WANG Wensheng WANG Xiaohong WANG Yicheng WANG Xiaogang WEI Qiwei WU Hongwei WU Pute WU Zhongru XIA Jun XU Zeping XU Zongxue XU Weilin YANG Dawen YANG Kailin YANG Xiaodong YAO Shuanxi YAO Wenyi YU Qiyang ZHANG Chaoran ZHANG Chunsheng ZHANG Guoxin ZHANG Limin ZHANG Jian ZHANG Jianmin ZHANG Jianyun ZHANG Yongbo ZHANG Zongliang ZHENG Peiming ZHONG Denghua ZHONG Pingan ZHONG Zhiyu ZHOU Xiaoguang ZHU Bofang ZHU Xingming ZUO QitingCHIEF EDITORCHENG XiaotaoDEPUTY CHIEF EDITORSLI Zantang GAN Hong XU ZepingOptimal operation of flood control for cascade reservoirs based on Parallel Chaotic QuantumParticle Swarm OptimizationZOU Qiang，WANG Xuemin，LI Anqiang，HE Xiaocong，LUO Bin（Changjiang Institute of Survey Planning Design and Research，Wuhan430074，China）Abstract：The optimal operation of flood control for cascade reservoirs is a huge-scale complex nonlinear problem，involving a large number of decision variables and complicated constraints，and there are complex coupling relationship among water level and flow rate in each reservoir and each time with high dimension，nonlinear，strong constraint characteristics.Therefore，the evolution with traditional methods are difficult to directly solve or have low computational efficiency with premature convergence.This research tried to adopt Quantum Particle Swarm Optimization（QPSO）for cascade reservoirs optimal operation of flood control，and in order to improve the convergence effect and global search capability of QPSO，three improvements were presented for QPSO，such as population initialization with chaotic theory，adaptive activation mechanism and chaotic local search for elite particles.Furthermore，with the aim of reducing the computational time，a multi-core parallel computation technology was also employed.Overall，on the basis of above three im⁃provements and multi-core parallel computation technology，Parallel Chaotic Quantum Particle Swarm Optimi⁃zation（PCQPSO）was proposed in the paper.Then test function demonstrated the practicability，stability and high effectiveness of PCQPSO.Finally，the case study based on PCQPSO shows that PCQPSO is fast convergence efficiency，high precision，and the outcomes of this research based on PCQPSO offer new in⁃sights to carry out an efficient strategy for optimal operation of cascade reservoirs flood control.Key words：cascade reservoirs；flood control optimal operation；Quantum Particle Swarm Optimization；cha⁃otic search；multi-core parallel computationSlope stability analysis by considering rainfall infiltration in multi-layered unsaturated soils SHI Zhenming1，2，SHEN Danyi1，2，PENG Ming1，2，ZHANG Lulu3，4，ZHANG Fawang5，ZHENG Xiaozhan6（1.Department of Geotechnical Engineering，Tongji University，Shanghai200092，China；2.Ministry of Education Key Laboratory of Geotechnical and Underground Engineering，Tongji University，Shanghai200092，China；3.State Key Laboratory Ocean Engineering，Shanghai Jiaotong University，Shanghai200240，China；4.Department of Civil Engineering，Shanghai Jiaotong University，Shanghai200240，China；5.Institute of karst geology，CAGS，Guilin541004，China；6.Guangdong Geologic Survey Institute，Guangzhou510440，China）Abstract：Rainfall is one of the major causes for slope failures.Rainfall infiltration reduces the slope resis⁃tance by largely lowering the matrix suction.The paper presents a method slope stability analysis of multi-layered unsaturated soils.Firstly，the Green-Ampt infiltration model is improved to calculate the infil⁃tration depth in multi-layered unsaturated soils.Then，the soil strength parameters are estimated with con⁃sideration of rain infiltration.Finally，stability analysis is conducted by using of strength reduction method with ABAQUS.The method is applied to the case study of the Dafushan landslide in Guanzhou and found that the shallow slip surface in the simulation is close to the real case.Slope stability analyses are further conducted with different rainfall intensity and lasting period.It is found from the analysis that the slide sur⁃face is most probably located in wetting front or at the interface between the soils and bedrock.The long term and low density antecedent rainfall makes larger infiltration depth and deep seated slope failure；the short term and high density antecedent rainfall usually cause smaller infiltration depth and shallow seated slope failure；with the increase of rainfall intensity，rainfall duration，the infiltration depth increases，and then aggravate the slope failure.Key words：rainfall infiltration；unsaturated soils；infiltration depth；strength parameters；slope stabilityMesoscale numerical analysis on moisture transportin cracked concrete subjected to drying-wetting cyclesWANG Licheng，BAO Jiuwen（State Key Laboratory of Coastal and Offshore Engineering，Dalian University of Technology，Dalian116024，China）Abstract：For the splash and tidal zone of marine concrete structures，there are two main existing forms of the moisture involving both gas and liquid phases，which exist within the pores of concrete.Based on the unsaturated flow theory of capillary absorption by concrete，the one-dimensional nonlinear differential equation for moisture transport in cracked concrete subjected to drying-wetting cycles is developed.With consideration of the transport hysteresis during drying and wetting period，the models accounting for moisture transport coefficients during this process in an individual crack are respectively proposed.In terms of the mesoscale methodology that the cracked concrete is treated as a four-phase composite material consisting of coarse aggregate，mortar，interfacial transition zone（ITZ）and crack，the two-dimensional lattice network model with a single crack is adopted to conduct the numerical simulation of moisture transport in cracked concrete subjected to drying-wetting pared with the existing experimental results，the proposed models are utilized to verify the transport theory of drying-wetting cycle in cracked concrete.Furthermore，by means of the above numerical models，the effect of drying-wetting cyclic mechanism（i.e.，the ratio of drying-wetting time and cyclic times）and crack width on water distribution of cracked concrete are numeri⁃cally carried out and reasonably analyzed.The numerical results suggest that water content distribution pro⁃files within the crack and in the location perpendicular to crack direction depend on the ratio of drying-wet⁃ting time and cycles for the constant crack width.For the crack width ranging between0.05-0.3mm，water content within the crack and perpendicular to crack direction decreases with the increase of crack width.Key Words：drying-wetting cycles；cracked concrete；moisture；mesoscale lattice model；crack widthContribution of hydrological and biological processes to nutrient retentionin an agricultural headwater stream predominated by Phragmites australisLI Ruzhong，CAO Jingcheng，HUANG Qingfei，YIN Xiaoxi，YAN Xiaosan （School of Resources and Environmental Engineering，Hefei University of Technology，Hefei230009，China）Abstract：To examine the contribution of hydrological and biological processes to nutrient retention in a headwater stream with growing lots of aquatic macrophytes，eight field tracer experiments were conducted at an agricultural headwater stream reach，predominated by Phragmites australis，in the Nanfeihe River from September2014to June2015.Such three typical hydrodynamic parameters as Reynolds numbers（Re），Froude numbers（Fr），and Manning roughness coefficient（n）of stream flows were calculated firstly accord⁃ing to the hydraulic data.Subsequently，both the practical and relative contributions of hydrological and bio⁃logical processes to NH4+and PO43-retention as well as the total retention ratios of the two nutrients were estimated quantitatively.Study results show that the stream reach displayed striking turbulence characteris⁃tics over the eight tracer experiments and its flow status belonged to subcritical flow.The values of n ranged from0.066to0.112，with a mean value of0.089.The proportional NH4+and PO43-retention ranged from9.17%to28.27%and5.75%to17.79%，with the averages of14.68%and12.53%，respectively.The practical contribution rates of hydrological and biological factors to NH4+retention were10.12%and4.57%，respectively，and10.12%and2.41%for PO43-，respectively.The relative contributions of hydrological and biological processes to NH4+retention were72.51%and27.49%，respectively，and81.42%and18.58%for PO43-，respectively.The findings mentioned above indicate that hydrological process has a greater impact on the retention of NH4+and PO43-for the studied stream reach.Moreover，relationship between the hydrody⁃namic parameters（i.e.Q，Re and Fr）and the Manning roughness coefficient（n）could be expressed by using power functions，but no obvious relationship has been found between the practical retention ratio（i.e.ηNH4，ηPO4）and the following hydrodynamic parameters as n and Re.Key words：agricultural stream；nutrient retention；aquatic macrophyte；tracer experiment；hydrodynamic parameterCharacteristics of Nitrate-N losses through runoffand hydrological tracing in subtropical agricultural catchments WANG Rui1，2，TANG Jialiang1，ZHANG Xifeng1，SHEN Dong1，ZHAI Longbo1，2，ZHU Bo1（1.Institute of Mountain Hazards and Environment，Chinese Academy of Sciences，Chengdu610041，China；2.University of Chinese Academy of Sciences，Beijing100049，China）Abstract：In order to understand the hydrological pathways of nitrate-N in subtropical agricultural catch⁃ments，this study was carried out at a nested agricultural headwater catchment in Hilly area of purple soil. Rainfall，discharge，δ18O，nitrate-N were monitored continuously in two storms.End member mixing analy⁃sis（EMMA）model was applied to quantify the contributions from different water sources.The results show that：（1）Surong catchment has the highest nitrate-N concentrations，while Wanan has the lowest nitrate-N，indicating that nitrate-N decreased with lager catchment size attribute to water dilution effect from other small watersheds which are dominated by woodland;（2）Subsurface flow from sloped croplands contributes to peak nitrate-N concentrations increased during the recession period of storm flow.The results of EMMA show that bothδ18O and nitrate-N successfully traced subsurface flow replenishment process during the flow recession period.But intense human activity might lead a certain deviation.In sum，nitrate-N has the poten⁃tial to be environmental indicator and hydrologic tracer simultaneously during storm events for small agricul⁃tural catchments.But its application in more storm events at multiple sites remains to be further validated. Key words：agricultural catchments；nitrate-N；storms runoff；hilly area of purple soil；hydrological tracingChanges in the turbulent characteristics for sediment bed coated by biofilm CHENG Wei1，2，FANG Hongwei1，2，HUANG Lei1，2，LAI Haojie1，2，HE Guojian1，2（1.Department of Hydraulic Engineering，Tsinghua University，Beijing100084，China；2.State Key Laboratory of Hydroscience and Engineering，Tsinghua University，Beijing100084，China）Abstract：Biofilm growth on the sediment bed will change the turbulent characteristics and influence the sediment incipient，suspension and transportation.In this study，sediment with median size d50<0.1mm is used to investigate the change of turbulent characteristics with and without biofilm coating on the bed un⁃der the same discharge.Acoustic Doppler Velometer（ADV）is used to obtain the instantaneous velocity in the vertical direction.Mean velocity，Reynold stress，turbulent intensity distribution and bursting events above the bed are analyzed and compared between the biofilm-coated bed and the bed without biofilm，the influence of which on the sediment transportation is also discussed.Results show that with biofilm coated，the mean velocity in vertical direction increase and the bed resistance decrease，Reynold stress and turbu⁃lent intensity also decrease near the bed，which may change the vertical distribution of suspended sedi⁃ment.Bursting events analysis shows a disadvantage of sediment incipient by the coated biofilm.Key words：sediment transport；biofilm；turbulent characteristicResearch on river health assessment based on different biological assessmblages LI Yanli1，LI Yanfen2，ZHAO Li1，XU Zongxue3，SUN Wei1（1.Institute of Resources&Environment，Henan Polytechnic University，Jiaozuo454000，China；2.Institute of Chemical and Environment Engineering，Jiaozuo College，Jiaozuo454000，China；3.College of Water Sciences，Beijing Normal University，Beijing100875，China）Abstract：In this study，a multimetric index based on fish and macroinvertebrate at the levels of communi⁃ty structure and function for the Hun-Taizi River basin（MMI-HT）was developed to assess river health. First，an index of land use，water and habitat quality（ILWHQ）was calculated to evaluate the environmen⁃tal quality in the studied sites.Then，core metrics were selected using a stepwise procedure（the analysis of the range of index value distribution，stepwise regression analysis，Pearson correlation）that evaluated metric stability，responsiveness to stressors.Finally，ration scoring method was used to score multimetric in⁃dex in the Hun-Taizi River（MMI-HT）.Eight metrics（Cyprinidae species，Proportion of benthic species，Proportion of omnivore species，Proportion of individuals as tolerant species，Proportion of demersal eggs species，Proportion of individuals as demersal eggs species，EPT，Proportion of clingers）were selected to construct MMI-HT.Generally，macroinvertebrate metrics were more sensitive to coarse substrate，electric conductivity and suspended solid，whereas，fish metrics were more sensitive to fine substrate，dissolved oxy⁃gen，chloride，nitrogen，Permanganate index，water temperature，land use and perturbations of hydrological processes.Two groups responded differently to multiple stressors.The results showed that nine sites were in excellent condition，six were in good condition，seven in normal condition，seven in poor condition，and six in very poor condition in the Taizi River basin.There was no site in excellent condition，five in good condition，four in normal condition，five in poor condition，and five in very poor condition in the Hun Riv⁃er basin.These findings indicate that ecosystem health is worse in the Hun River than that in the Taizi River.Key words：multimetric assessment；fish；macroinvertebrate；land use index；riverMechanism of the intermittent motion of two-phase debris flows headand the energy characterLÜLiqun1，WANG Zhaoyin1，CUI Peng2（1.State Key Laboratory of Hydroscience and Engineering，Tsinghua University，Beijing100084，China；2.Mountain Hazard and the Earth's Surface Processes Key Laboratory，Institute of Mountain Hazards and Environment，Chinese Academy of Sciences，Chengdu610041，China）Abstract：A typical two-phase debris flow exhibits a high and steep flow head consisting of rolling boul⁃ders and cobbles and intermittent or fluctuating moving velocity.The relative motion between the solid phase and the liquid phase is obvious.The motion of a two-phase debris flow depends on not only the rhe⁃ological properties of the flow，but also the energy transmission between the solid and liquid phases.In ad⁃dition to the rheological characteristics of two-phase debris flow，energy transfer between liquid phase and solid phase plays an important role.Energy analysis method was used to study the energy transfer mecha⁃nism between the two phase flows and simulate the motion of two-phase flow.This paper analyzed the inter⁃mittent feature of two-phase debris flows based on videos of field debris flows and flume experiments.The experiments showed that the height of the head of the two-phase debris flow increased gradually at the initi⁃ation stage and reached equilibrium at a certain distance.The height growth and the velocity of the flow head showed fluctuating characteristics.Physical equations were established and the analyses proved that the average velocity of the two-phase debris flow head was proportional to the gully slope and flood discharge，and inversely proportional to the volume of the debris flow head.Key words：two-phase debris flow；intermittent motion；unsteady flow；flow power；energy dissipation.Investigation on hydraulic transientsin tailrace tunnel with air inlet and release from the ventYU Xiaodong1，2，ZHANG Jian2（1.State Key Laboratory of Water Resources and Hydropower Engineering Science，Wuhan430072，China；2.College of Water Conservancy and Hydropower Engineering，Hohai University，Nanjing210098，China）Abstract：Based on the one-dimensional hydraulic transients and the method of characteristics（MOC），the mathematical model of the vent in the tail race tunnel is established by using the Discrete Free-Gas Cavity Model（DGCM），and the thermodynamic properties of the gas is taking into account as well.A cor⁃responding numerical model has been developed using the data of a real hydropower station，and the phe⁃nomenon of air inlet-two phase flow-air releases is investigated during transient process.The results show that air inlet can effectively relieve the negative pressure in the tunnel，but air releases can lead to a large impact pressure，which comes from the water column rejoin after the separation by the air，resulting in the direct water hammer.When the area of the vent is large，the impact pressure decreases with the in⁃crease of the area，when the area of the vent is small，the impact pressure increases with the increase of the area.According to its characteristics，the structure of a new type of vent is presented，i.e.，the vent is fully open when the air flows in，and the vent is partly open when the air flows out.When the air re⁃leases area is about10%of the air inlet area，the pressure oscillation is small.Key words：hydropower station；hydraulic transients；vent；tailrace tunnel；air pocketInvestigating the circle pipe’s roughness withthe fractal geometry theory and the practical applicationZHANG Landing（Nanjing Hydraulic Research Institute，Nanjing210029，China）Abstract：The author analyzes the important effects of equivalent roughness K S in calculating the friction losses of turbulent flow，based on the existing theoretical and experimental research achievements of resis⁃tance laws，as well as depicts the situation of calculating the friction losses and applicationin China’s hy⁃draulic engineering.For the case of circle pipe’s roughness，the author researches on the fractal characteris⁃tics of roughness of pipe’s inner wall with the fractal geometry theory，and gives the mathematical model of the fractal dimension and numerical examples.The author also demonstrates the relationship between the fractal dimension and equivalent roughness K S，the calculation methods of fractal dimension of pipe rough⁃ness in longitudinal and transverse are discussed respectively，then gives way to apply the turbulent resis⁃tance laws and research achievements provided by the former to engineering practice directly.Key words：fractal geometry；circle pipe；equivalent roughness；fractal dimension；friction lossesFracture toughness of concrete after carbonation andwet-dry cycle of sulfate solutionZHANG Tingyi1，2，WANG Zili1，2，ZHENG Guanghe1，2，ZHU Haitang3（1.Yellow River Institute of Hydraulic Research，Zhengzhou450003，China；2.Research Center on Levee Safety&Disaster Prevention，the Ministry of Water Resources，Zhengzhou450003，China；3.School of Water Conservancy and Environment Zhengzhou University，Zhengzhou450002，China）Abstract：In this paper，the effects of deteriorations is studied，such as carbonation and wet-dry cycle in sulfate solution，upon fracture toughness of concrete.Through the three-point bending test on the notched beams of concrete after carbonation and wet-dry cycle in sulfate solution，the effects of carbon⁃ation time（t）and wet-dry cycle number（n）upon the fracture toughness of concrete were studied.The re⁃sults show that carbonation and wet-dry cycle deteriorate the fracture toughness to some extent.Degradation factor（R）is less than1.Fracture toughness decreases as t（or n）increases.R significantly decreases as（or n）increases，and statistical analysis indicates that t and n meet the relation of exponential function with R respectively.Because of the obvious interaction between carbonation and wet-dry cycle，the individual ef⁃fect of carbonation（or wet-dry cycle）is more serious than the alternate one.Based on the test results，the calculation model is established for calculating fracture toughness of concrete deterioration.This model is helpful to analyze the crack propagation and fracture toughness of concrete deterioration.Key words：carbonation；sulfate solution；wet-dry cycle；concrete；fracture toughnessBearing mechanism of reinforced concrete penstock with steel liner consideringfriction-contact behaviorSU Kai1，ZHANG Wei2，WU Hegao1，SHI Changzheng1（1.State Key Laboratory of Water Resources and Hydropower Engineering Science，Wuhan University，Wuhan430072，China；2.Civil Engineering and Architecture College of Guangxi University，Nanning530004，China）Abstract：Coulomb friction model is employed to simulate the friction-contact behavior between steel liner and reinforced concrete when a numerical model of reinforced concrete penstock with steel liner located on the downstream surface of concrete dam is built up.The critical pressure of concrete crack initiation，con⁃crete crack propagation law，penstock deformation characteristic and stresses distribution of steel are ana⁃lyzed upon the friction-contact model（FCM）.Some impressive conclusions can be achieved from the re⁃sults：the concrete crack propagation law of FCM meets the experiments’results well；the differences of tensile stress of the steel liner between the crown and the bottom are less than the traditional node shared model when FCM model is adopted；the width of the concrete crack of FCM model ranges from0.3to 0.4，larger than traditional node shared model；non-uniformities of both the displacement around the pen⁃stock crown and the steel liner tensile stresses increase with the friction while tensile stresses values and strain non-uniformities of the cross-crack-reinforcement decrease when the friction are larger.The results in⁃dicate that the rebar stresses are less while the non-uniform of liner stresses are greater when the combina⁃tions between steel liner and surrounding concrete are enhanced.Key words：penstock；reinforced concrete penstock with steel liner；friction-contact behavior；bearing mechanismDiscrete and continuous coupling numerical simulation of the impact loadingJIA Mincai1，2，CHEN Chun1，2，WU Shaohai3（1.Department of Geotechnical Engineering，Tongji University，Shanghai200092，China；2.Key Laboratory of Geotechnical and Underground Engineering.of Education Ministry，Tongji University，Shanghai200092，China；3.China Railway Eryuan Engineering Group Co.Ltd.，Chengdu610031，China）Abstract：Dynamic compaction and impact rolling have been widely used in hydraulic engineering（e.g. port engineering and dam engineering）.The research about complex dynamic characteristics mainly depends on laboratory model tests and engineering experience，while the numerical method was rarely bin⁃ing the discrete element method（DEM）and finite difference method（FDM），a discrete and continuous coupling model was established to simulate dynamic compaction.The hysteretic damping model of the PFC2D is used in the important area，while the surrounding area is simulated with Mohr-Coulomb model of FLAC2D.According to the force equilibrium principle，the resultant force and bending moment acting on the boundary wall are distributed to the boundary node of continuous model.Due to the fact that the coupled boundary could not bear tensile stress，adjustment is made to transfer the boundary surface stresses，and the velocity of boundary wall is determined by the velocity of boundary node.The numerical results were compared with those of laboratory tests and the feasibility of the coupling simulation was validated，which provides a new method for dynamic improvement and stability analysis of dam and port.Key words：impact load；discrete element method；finite difference method；discrete and continuous cou⁃pling；dynamic characteristics。

2020年杭州育才中学高三英语一模试卷及参考答案第一部分阅读（共两节，满分40分）第一节（共15小题；每小题2分，满分30分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项AHow to Look at ShapeTake a seat at the virtual(虚拟的) table. At our new, monthly membership program, you'll join MoMA staff and fellow members for lively discussions about our collection and exhibitions. Ask questions, share your thoughts, and broaden the mind. A live Q&A, with Michelle Kuo and Anny Aviram, about shape and its role in MoMA's collection is also arranged.Draw, Write, and Connect with OthersExperiment with drawing and writing exercises as ways to connect with others, even when physically distant, in this 45-minute online workshop. This workshop is part of the Creativity Lab at Home plan. This session is led by Francis Estrada, Assistant Educator, and Hannah Fagin, Coordinator. Ifs open to anyone, but registration is limited and space is available on a first-come, first-served basis.Storytelling Through ArtThere are many ways to tell a story — through words through theater and dance, or through visual art, for example. Discover how artist Jacob Lawrence shared the history of an important event by combining words and art in a series of paintings calledThe Migration Series. For kids ages seven to fourteen. Parent participation is encouraged in this online event. Don' miss the opportunity to spend meaningful time with them.The Human ShelterIn 2016, MoMA opened Insecurities: Tracing Displacement and Shelter, an exhibition that examined how contemporary architecture arid design addressed ideas of shelter in light of global refugee(难民) emergencies. Danish Boris Benjamin Bertram documented the exhibition, and the result is a movie by him asking what makes a home, and, perhaps more importantly, when shelter becomes home. This online event is part of Member events.1.What is special about How to Look at Shape?A.It provides an interactive part.B.It is accessible to everyone.C.It is organized by Michelle Kuo.D.It focuses on MoMA's new collection.2.Which event is family-friendly?A.The Human Shelter.B.How to Look at Shape.C.Storytelling Through Art.D.Draw, Write, and Connect with Others.3.In which aspect might Bertram do well?A.Shelter design.B.Storytelling.C.Art education.D.Film-making.BWhen almost everyone has a mobile phone, why are more than half of Australian homes still paying for a landline（座机）?These days you’d be hard pressed to find anyone in Australia over the age of 15 who doesn’t own a mobile phone. In fact plenty of younger kids have one in their pocket. Practically everyone can make and receive calls anywhere, anytime.Still, 55 percent of Australians have a landline phone at home and only just over a quarter（29%）rely only on their smartphones according to a survey（调查）. Of those Australians who still have a landline, a thirdconcedethat it’s not really necessary and they’re keeping it as a security blanket — 19 percent say they never use it while a further13 percent keep it in case of emergencies. I think my home falls into that category.More than half of Australian homes are still choosing to stick with their home phone. Age is naturally a factor （因素）— only 58 percent of Generation Ys still use landlinesnow and then, compared to 84 percent of Baby Boomers who’ve perhaps had the same home number for 50 years. Age isn’t the only factor; I’d say it’s also to do with the makeup of your household.Generation Xers with young families, like my wife and I, can still find it convenient to have a home phone rather than providing a mobile phone for every family member. That said, to be honest the only people who ever ring our home phone are our Baby Boomers parents, to the point where we play a game and guess who iscalling before we pick up the phone（using Caller ID would take the fun out of it）.How attached are you to your landline? How long until they go the way of gas street lamps and morning milk deliveries?4. What does paragraph 2 mainly tell us about mobilephones?A. Their target users.B. Their wide popularity.C. Their major functions.D. Their complex design.5. What does the underlined word “concede” in paragraph 3 mean?A. Admit.B. Argue.C. Remember.D. Remark.6. What can we say about Baby Boomers?A. They like smartphone games.B. They enjoy guessing callers’ identity.C. They keep using landline phones.D. They are attached to their family.7. What can be inferred about the landline from the last paragraph?A. It remains a family necessity.B. Itwill fall out of use some day.C. It may increase daily expenses.D. It is as important as the gas light.CThe far side of the moonis a strange and wild region, quite different from the familiar and mostly smooth face we see nightly from our planet. Soon this rough space will have even stranger features: it will be crowded with radio telescopes.Astronomers are planning to make the moon's distant side our newest and best window on the cosmic(宇宙的) dark ages, a mysterious era hiding early marks of stars and galaxies. Our universe was not always filled with stars. About 380,000 years after the big bang, the universe cooled, and the first atoms of hydrogen formed. Gigantic hydrogen clouds soon filled the universe. But for a few hundred million years, everything remained dark, without stars. Then came the cosmic dawn: the first stars flickered, galaxies came into existence and slowly the universe's large­scale structure took shape.The seeds of this structure must have been present in the dark­age hydrogen clouds, but the era has been impossible toprobeusing optical(光学的) telescopes—there was no light. And although this hydrogen produced long­wavelength(or low­frequency) radio emissions,radio telescopes on Earth have found it nearly impossible to detect them. Our atmosphere either blocks or disturbs these faint signals; those that get through are drowned out by humanity's radio noise.Scientists have dreamed for decades of studying the cosmic dark ages from the moon's far side. Now multiple space agencies plan lunar missions carrying radio­wave­detecting instruments—some within the next three years—and astronomers' dreams are set to become reality.“If I were to design an ideal place to do low­frequency radio astronomy, I would have to build the moon,”says astrophysicist Jack Burns of the University of Colorado Boulder. “We are just now finally getting to the place where we're actually going to be putting these telescopes down on the moon in the next few years.”8. What's the purpose of building radio telescopes on the moon?A To research the big bang. B. To discover unknown stars.C. To study the cosmic dark ages.D. To observe the far side of the moon.9. What does the underlined word “probe” in Paragraph 3 possibly mean?A. Explore.B. Evaluate.C. Produce.D. Predict.10. Hydrogen radio emissions can't be detected on Earth because ________．A. there was no light in the dark agesB. they cannot possibly get through our atmosphereC. gigantic hydrogen clouds no longer fill the universeD. radio signals on Earth cause too much interference11. What can we infer from theunderlined sentence in the last paragraph?A. Scientists have to rebuild the moon.B. We will finally get to the moon's distant side.C. The moon is a perfect place to set up radio telescopes.D. A favorable research environment will be found on the moon.DThe Nez Perce Indians are a tribe that lived in the Pacific Northwest of theUnited States. At the time of the Lewis and Clark expedition (探险队) , which was one of the first journeys by Americans from the Atlantic coast to the Pacific coast and back again, the Nez Perce territory (领土) covered about 17 million acres, covering parts of Washington, Oregon, and Idaho. Butthat was a brief sweet history.In September 1805, when Lewis and Clark came off theRockieson their westward journey, the entire exploring party was hungry and ill -- too weak to defend themselves.Had the Nez Perce chosen to attack them, they could have put an end to the Lewis and Clark expedition there on the banks ofClearwater River. Instead the Nez Perce welcomed the white Americans and looked after them until they made a full recovery. Thus began a long friendship between the Nez Perce and white Americans. But white men’s greed for land and gold finally broke the friendship.In 1855 Governor Isaac Stevens ofWashingtonTerritoryinvited the Nez Perce to a peace conference. He said there were a great many white people in the country, and many more would come. But the Chief of the tribe at that time, Old Joseph, replied, “Take away your paper. I will not touch it with my hand.”Things were quiet for a while after that, but not for long. When Old Joseph died, the chiefship was passedonto Young Joseph. In the late 1870s, government officials came to order the Nez Perce to leave theWallowaValleyand then began hard battles between the Nez Perce and the white soldiers. After the tribe had fought thirteen battles and moved 1,600 miles to-wards Canada in an attempt to retreat(撤退) north, Young Joseph, gave in to the United States Army. Here was his famous statement, “Hear me my chiefs. I am tired; my heart is sick and sad. From where the sun now stands I will fight no more forever.”In 1885, Chief Joseph was sent along with manyof his band to the Colville Reservation inWashingtonwhere Joseph continued to lead his band for another 25 years, at times coming into conflict with the leaders of 11 other tribes living on the reservation.(保留地，居留地)12. What isTRUEabout the Lewis andClark expedition?A. They were well cared for by the Nez Perce.B. They ended their expedition on the banks ofClearwater River.C. They started the first battle with the Nez Perce.D. They were the first Americans to travel from theAtlanticto the Pacific.13. What ended the friendship between the Nez Perce and the Whites?A. Old Joseph’s proud mannerB. White men’s increasing demand for land and goldC. A growing number of white men in the landD The breakdown of the peace talk14. Young Joseph gave in at last because ________.A. he grew olderB. he was terribly illC. he hated the warD. he lost other chiefs’ support15. The passage might be followed by a paragraph about ________.A. the customs and traditions of the Nez Perce IndiansB. the last years of Chief Joseph in the Colville ReservationC. lasting fights between the Nez Perce and the whitesD. constant conflicts between the Nez Perce and other tribes第二节（共5小题；每小题2分，满分10分）阅读下面短文，从短文后的选项中选出可以填入空白处的最佳选项。

CameraFrom Wikipedia, the free encyclopediaJump to: navigation, searchFor other uses, see Camera (disambiguation).Section through a modern single-lens reflex cameraLeft to right: an Agfa box camera, a Polaroid Land camera, and a Yashica 35 mm SLR A camera is a device that records images, either as a still photograph or as movingimages known as videos or movies. The term comes from the camera obscura (Latin for "dark chamber"), an early mechanism of projecting images where an entire room functioned as a real-time imaging system; the modern camera evolved from the camera obscura.Cameras may work with the light of the visible spectrum or with other portions of the electromagnetic spectrum. A camera generally consists of an enclosed hollow with an opening (aperture) at one end for light to enter, and a recording or viewing surface for capturing the light at the other end. A majority of cameras have a lens positioned in front of the camera's opening to gather the incoming light and focus all or part of the image on the recording surface. The diameter of the aperture is often controlled by a diaphragm mechanism, but some cameras have a fixed-size aperture.A typical still camera takes one photo each time the user presses the shutter button. A typical movie camera continuously takes 24 film frames per second as long as the user holds down the shutter button.Contents[hide]∙ 1 History∙ 2 Mechanicso 2.1 Image captureo 2.2 Lenso 2.3 Focuso 2.4 Exposure controlo 2.5 Shutters∙ 3 Film formats∙ 4 Camera designso 4.1 Plate camerao 4.2 Large formatcamerao 4.3 Folding camerao 4.4 Box camerao 4.5 Rangefindercamerao 4.6 Single-lens reflexo 4.7 Twin-lens reflexo 4.8 Ciné camera∙ 5 Image gallery∙ 6 See alsoo 6.1 Typeso 6.2 Brandso 6.3 Other∙7 References8 External links[edit] HistoryMain article: History of the cameraCamera obscura.The forerunner to the camera was the camera obscura.[1]The camera obscura is an instrument consisting of a darkened chamber or box, into which light is admittedthrough a convex lens, forming an image of external objects on a surface of paper or glass, etc., placed at the focus of the lens.[2] The camera obscura was first invented by the Iraqi scientist Ibn al-Haytham(Alhazen) as described in his Book of Optics (1015-1021).[3]Irish scientist Robert Boyle and his assistant Robert Hooke later developed a portable camera obscura in the 1660s.[4]The first camera that was small and portable enough to be practical for photography was built by Johann Zahn in 1685, though it would be almost 150 years before technology caught up to the point where this was practical. Early photographic cameras were essentially similar to Zahn's model, though usually with the addition of sliding boxes for focusing. Before each exposure, a sensitized plate would be inserted in front of the viewing screen to record the image. Jacques Daguerre's popular daguerreotype process utilized copper plates, while the calotype process invented by William Fox Talbot recorded images on paper.The first permanent colour photograph, taken by James Clerk Maxwell in 1861.The first permanent photograph was made in 1826 by Joseph Nicéphore Niépce usinga sliding wooden box camera made by Charles and Vincent Chevalier in Paris. Niépce built on a discovery by Johann Heinrich Schultz (1724): a silver and chalk mixture darkens under exposure to light. However, while this was the birth of photography, the camera itself can be traced back much further. Before the invention of photography, there was no way to preserve the images produced by these cameras apart from manually tracing them.The development of the collodion wet plate process by Frederick Scott Archer in 1850 cut exposure times dramatically, but required photographers to prepare and develop their glass plates on the spot, usually in a mobile darkroom. Despite their complexity, the wet-plate ambrotype and tintype processes were in widespread use in the latter half of the 19th century. Wet plate cameras were little different from previous designs, though there were some models, such as the sophisticated Dubroni of 1864, where the sensitizing and developing of the plates could be carried out inside the camera itself rather than in a separate darkroom. Other cameras were fitted with multiple lenses for making cartes de visite. It was during the wet plate era that the use of bellows for focusing became widespread.The first colour photograph was made by Scottish physicist James Clerk Maxwell, with the help of English inventor and photographer Thomas Sutton, in 1861[5][edit] Mechanics[edit] Image capturesee also Photographic lens design19th century studio camera, with bellows for focusing.Traditional cameras capture light onto photographic film or photographic plate. Video and digital cameras use electronics, usually a charge coupled device(CCD) or sometimes a CMOS sensor to capture images which can be transferred or stored in tape or computer memory inside the camera for later playback or processing. Cameras that capture many images in sequence are known as movie cameras or as ciné cameras in Europe; those designed for single images are still cameras. However these categories overlap. As still cameras are often used to capture moving images in special effects work and modern digital cameras are often able to trivially switch between still and motion recording modes. A video camera is a category of movie camera that captures images electronically (either using analogue or digital technology).[edit] LensMain article: Photographic lensMain article: Photographic lens designThe lens of a camera captures the light from the subject and brings it to a focus on the film or detector. The design and manufacture of the lens is critical to the quality of the photograph being taken. The technological revolution in camera design in the 18th century revolutionised optical glass manufacture and lens design with great benefits for modern lens manufacture in a wide range of optical instruments from reading glasses to microscopes. Pioneers included Zeiss and Leitz.[edit] FocusAuto-focus systems can capture a subject a variety of ways; here, the focus is on the person's image in the mirror.Due to the optical properties of photographic lenses, only objects within a limited range of distances from the camera will be reproduced clearly. The process of adjusting this range is known as changing the camera's focus. There are various ways of focusing a camera accurately. The simplest cameras have fixed focus and use a small aperture and wide-angle lens to ensure that everything within a certain range of distance from the lens, usually around 3 metres (10 ft) to infinity, is in reasonable focus. Fixed focus cameras are usually inexpensive types, such as single-use cameras. The camera can also have a limited focusing range or scale-focus that is indicated on the camera body. The user will guess or calculate the distance to the subject and adjust the focus accordingly. On some cameras this is indicated by symbols (head-and-shoulders; two people standing upright; one tree; mountains). Rangefinder cameras allow the distance to objects to be measured by means of a coupled parallax unit on top of the camera, allowing the focus to be set with accuracy. Single-lens reflex cameras allow the photographer to determine the focus and composition visually using the objective lens and a moving mirror to project the image onto a ground glass or plastic micro-prism screen. Twin-lens reflex cameras use an objective lens and a focusing lens unit (usually identical to the objective lens.) in a parallel body for composition and focusing. View cameras use a ground glass screen which is removed and replaced by either a photographic plate or a reusable holder containing sheet film before exposure. Modern cameras often offer autofocus systems to focus the camera automatically by a variety of methods e.g. by fishing.[6][edit] Exposure controlThe size of the aperture and the brightness of the scene controls the amount of light that enters the camera during a period of time, and the shutter controls the length of time that the light hits the recording surface. Equivalent exposures can be made with a larger aperture and a faster shutter speed or a corresponding smaller aperture and with the shutter speed slowed down.[edit] ShuttersMain article: Shutter (photography)Although a range of different shutter devices have been used during the development of the camera only two types have been widely used and remain in use today.The focal plane shutter operates as close to the film plane as possible and consists of cloth curtains that are pulled across the film plane with a carefully determined gap between the two curtains or consisting of a series of metal plates moving either vertically or horizontally across the film plan. As the curtains or blades move at a constant speed, exposing the whole film plane can takes much longer than the exposure time. For example an exposure of 1/1000 second may be achieved by the shutter curtains moving across the film plane in 1/50th of a second but with the twocurtains only separated by 1/20th of the frame width. When photographing rapidly moving objects, the use of a focal plane shutter can produce some unexpected effects. Focal plane shutters are also difficult to synchronise with electronic flash and it is often only possible to use flash at shutter speeds below 1/60th second although in some modern cameras that can be as fast as 1/100second/The Copal shutter or more precisely the in-lens shutter is a shutter contained within the lens structure, often close to the diaphragm consisting of a a number of metal leaves which are maintained under spring tension and which are opened and then closed when the shutter is released. The exposure time is determined by the interval between opening and closing. In this shutter design, the whole film frame is exposed at one time. This makes flash synchronisation much simpler as the flash only needs to fire once the shutter is fully open. This disadvantage of such shutters is their inability to reliably produce very fast shutter speeds and the additional cost and weight of having to include a shutter mechanism for every lens.[edit] Film formatsMain article: Film formatsA wide range of film and plate formats have been used by cameras. In the early history plate sizes were often specific for the make and model of camera although there quickly developed some standardisation for the more popular cameras. Theintroduction of roll-film drove the standardisation process still further so that by the 1950s only a few standard roll films were in use. These included 120 film providing 8, 12 or 16 exposures, 220 film providing 16 or 24 exposures, 127 film providing 8 exposures , principally in Brownie 125 cameras and 35mm film providing 12, 20 or 36 exposures - or up to 72 exposures in bulk cassettes for the Leica range.For cine cameras, 35mm film was the original film format but 16mm film soon followed produced by cutting 35mm in two. An early amateur format was 9.5mm. Later formats included 8mm film and Super 8.[edit] Camera designs[edit] Plate cameraThe earliest cameras produced in significant numbers used sensitised glass plates and are now termed plate cameras. Light entered a lens mounted on a lens board which was separated from the plate by an extendible bellows. Many of these cameras, had controls to raise or lower the lens and to tilt it forwards or backwards to control perspective . Focussing of these plate cameras was by the use of a ground glass screen at the point of focus. Because lens design only allowed rather small aperture lenses, the image on the ground glass screen was faint and most photographers had a darkcloth to cover their heads to allow focussing and composition to be carried out more easily. When focus and composition were satisfactory, the ground glass screen was removed and a sensitised plate put in its place protected by a dark slide (photography) . To make the exposure, the dark slide was carefully slid out and the shutter opened and then closed and the dark-slide replaced. In current designs the plate camera is best represented by the view camera.[edit] Large format cameraMain article: View cameraThe large format camera is a direct successor of the early plate cameras and remain in use for high quality photography and for technical, architectural and industrialism photography. There are three common types, the monorail camera, the field camera and the press camera. All use large format sheets of film and have an extensible bellows with the lens and shutter mounted on a lens plate at the front. These cameras have a wide range of movements allowing very close control of focus and perspective. Some single lens reflex cameras and twin lens reflex cameras using film larger than 35 mm are also termed "large format " cameras, especially in the photographic press, to distinguish them from their smaller 35 mm cousins.[edit] Folding cameraThe introduction of films enabled the existing designs for plate cameras to be made much smaller and for the base-plate to be hinged so that it could be folded up compressing the bellows. These designs were very compact and small models were dubbed Vest pocket cameras.[edit] Box cameraBox cameras were introduced as a budget level camera and had few if any controls. The original box Brownie models had a small reflex viewfinder mounted on the top of the camera and had no aperture or focussing controls and just a simple shutter. Later models such as the Brownie 127 had larger direct view optical viewfinders together with a curved film path to help compensate for the imperfections of the simple lens system. Despite their lack of controls, box cameras sold in large numbers and helped to popularise photography for the wider public.[edit] Rangefinder cameraMain article: Rangefinder cameraAs camera and lens technology developed and wide aperture lenses became more common range-finder cameras were introduced to make focussing more precise. Therange finder had two separated viewfinder windows one of which was linked to the focusing mechanisms and moved right or left as the focussing ring was turned. The two separate images were brought together on a ground glass viewing screen. When vertical lines in the object being photographed met exactly in the combined image, the object was in focus. A normal composition viewfinder was also provided.[edit] Single-lens reflexMain article: Single-lens reflex cameraIn the single-lens reflex camera the photographer see the scene through the camera lens. This avoids the problems of parallax which occurs when the viewfinder or viewing lens is separated from the taking lens. Single-lens reflex cameras have been made in several formats including 220/120 taking 8, 12 or 16 photographs on a 120 roll and twice that number of a 220 film. These correspond to 6x9, 6x6 and 6x4.5 respectively (all dimensions in cm). Notable manufacturers of large format SLR include Hasselblad, Mamiya, Bronica and Pentax. However the most common format of SLRs has been 35 mm and subsequently the migration to digital SLRs, using almost identical sized bodies and sometimes using the same lens systems.Almost all SLR used a front surfaced mirror in the optical path to direct the light from the lens via a viewing screen and pentaprism to the eyepiece. At the time of exposure the mirror flipped up out of the light path before the shutter opened. Some earlycameras experimented other methods of providing through the lens viewing including the use of a semi transparent pellicle as in the Canon Pellix[7] and others with a small periscope such as in the Corfield Periflex series[8][edit] Twin-lens reflexMain article: Twin-lens reflex cameraTwin-lens reflex cameras used a pair of nearly identical lenses, one to form the image and one as a viewfinder. The lens were arranged with the viewing lens immediately above the taking lens. The viewing lens projects an image onto a viewing screen which can be seen from above. Some manufacturers such as Mamiya also provided a reflex head to attach to the viewing screen to all the camera to be held to the eye when in use. The advantage of a TLR was that it could be easily focussed using the viewing screen and that under most circumstances the view seen in the viewing screen was identical to that recorded on film. At close distances however, parallax errors were encountered and some cameras also included an indicator to show what part of the composition would be excluded.Some TLR had interchangeable lenses but as these had to be paired lenses they were relatively heavy and did not provide the range of focal lengths that the SLR could support. Although most TLRs used 120 or 220 film some used 127 film.[edit] Ciné cameraMain article: Movie cameraA ciné camera or movie camera is a type of photographic camera which takes a rapid sequence of photographs on strips of film. In contrast to a still camera, which captures a single snapshot at a time, the ciné camera takes a series of images, each called a "frame" through the use of an intermittent mechanism. The frames are later played back in a ciné projector at a specific speed, called the "frame rate" (number of frames per second). While viewing, a person's eyes and brain merge the separate pictures together to create the illusion of motion. The first ciné camera was built around 1888 and by 1890 several types were being manufactured. The standard film size for cinécameras was quickly established as 35mm film and this remains in use to this day. Other professional standard formats include 70 mm film and 16mm film whilst amateurs film makers have used 9.5 mm film, 8mm film or Standard 8 and Super 8 before the move into digital format. The size and complexity of ciné cameras varies greatly depending on the uses required of the camera. Some professional equipment is very large and too heavy to be hand held whilst some amateur cameras were designed to be as small and light as possible enabling single-handed operation.[edit] Image gallery1921 KodakOpened up CineKodak, used35mm movie filmSilvestriFlexicamV oigtländer Brillant twin-lensreflex camera.Contax S of 1949 —the world's first pentaprism SLR1952 V oigtlanderVito IIAsahiflex IIaof 1955Kodak Retina IIIC of 1957Nikon F of 1959 —the first 35mm system camera V oigtländerVitoret of 19621988 ASoviet-eraLOMOLC-Acamera2003 —Canon EOS 300D, amodel that sparked thepopularity of consumer-levelDSLRs。