Chemical Enrichment and the Origin of the Colour-Magnitude Relation of Elliptical Galaxies

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应用地球化学元素丰度数据手册-原版

应用地球化学元素丰度数据手册-原版

应用地球化学元素丰度数据手册迟清华鄢明才编著地质出版社·北京·1内容提要本书汇编了国内外不同研究者提出的火成岩、沉积岩、变质岩、土壤、水系沉积物、泛滥平原沉积物、浅海沉积物和大陆地壳的化学组成与元素丰度,同时列出了勘查地球化学和环境地球化学研究中常用的中国主要地球化学标准物质的标准值,所提供内容均为地球化学工作者所必须了解的各种重要地质介质的地球化学基础数据。

本书供从事地球化学、岩石学、勘查地球化学、生态环境与农业地球化学、地质样品分析测试、矿产勘查、基础地质等领域的研究者阅读,也可供地球科学其它领域的研究者使用。

图书在版编目(CIP)数据应用地球化学元素丰度数据手册/迟清华,鄢明才编著. -北京:地质出版社,2007.12ISBN 978-7-116-05536-0Ⅰ. 应… Ⅱ. ①迟…②鄢…Ⅲ. 地球化学丰度-化学元素-数据-手册Ⅳ. P595-62中国版本图书馆CIP数据核字(2007)第185917号责任编辑:王永奉陈军中责任校对:李玫出版发行:地质出版社社址邮编:北京市海淀区学院路31号,100083电话:(010)82324508(邮购部)网址:电子邮箱:zbs@传真:(010)82310759印刷:北京地大彩印厂开本:889mm×1194mm 1/16印张:10.25字数:260千字印数:1-3000册版次:2007年12月北京第1版•第1次印刷定价:28.00元书号:ISBN 978-7-116-05536-0(如对本书有建议或意见,敬请致电本社;如本社有印装问题,本社负责调换)2关于应用地球化学元素丰度数据手册(代序)地球化学元素丰度数据,即地壳五个圈内多种元素在各种介质、各种尺度内含量的统计数据。

它是应用地球化学研究解决资源与环境问题上重要的资料。

将这些数据资料汇编在一起将使研究人员节省不少查找文献的劳动与时间。

这本小册子就是按照这样的想法编汇的。

乙酸蒸汽催化重整制氢的研究进展

乙酸蒸汽催化重整制氢的研究进展

CHEMICAL INDUSTRY AND ENGINEERING PROGRESS 2017年第36卷第5期·1658·化 工 进展乙酸蒸汽催化重整制氢的研究进展王东旭1,肖显斌2,李文艳1(1华北电力大学能源动力与机械工程学院,北京 102206;2华北电力大学生物质发电成套设备国家工程实验室,北京 102206)摘要:通过生物油蒸汽重整制备氢气可以减少环境污染,降低对化石燃料的依赖,是一种极具潜力的制氢途径。

乙酸是生物油的主要成分之一,常作为模型化合物进行研究。

镍基催化剂是乙酸蒸汽重整过程中常用的催化剂,但容易因积炭失去活性,降低了制氢过程的经济性。

本文首先分析了影响乙酸蒸汽重整制氢过程的各种因素,阐述了在这一过程中镍基催化剂的积炭原理,讨论了优化镍基催化剂的方法,包括优化催化剂的预处理过程、添加助剂和选择合适的载体,最后对乙酸蒸汽重整制氢的热力学分析研究进展进行了总结。

未来应重点研究多种助剂复合使用时对镍基催化剂积炭与活性的影响,分析多种助剂的协同作用机理,得到一种高活性、高抗积炭能力的用于生物油蒸汽重整制氢的镍基催化剂。

关键词:生物油;乙酸;制氢;催化剂;热力学中图分类号:TK6 文献标志码:A 文章编号:1000–6613(2017)05–1658–08 DOI :10.16085/j.issn.1000-6613.2017.05.014A review of literatures on catalytic steam reforming of acetic acid forhydrogen productionWANG Dongxu 1,XIAO Xianbin 2,LI Wenyan 1(1 School of Energy ,Power and Mechanical Engineering ,North China Electric Power University ,Beijing 102206,China ;2 National Engineering Laboratory for Biomass Power Generation Equipment ,North China Electric PowerUniversity ,Beijing 102206,China )Abstract :Hydrogen production via steam reforming of bio-oil ,a potential way to produce hydrogen , can reduce environmental pollution and dependence on fossil fuels. Acetic acid is one of the main components of bio-oil and is often selected as a model compound. Nickel-based catalyst is widely used in the steam reforming of acetic acid ,but it deactivates fast due to the carbon deposition. In this paper ,the affecting factors for the steam reforming of acetic acid are analyzed. The coking mechanism of nickel-based catalyst in this process is illustrated. Optimization methods for nickel-baed catalyst are discussed ,including optimizing the pretreatment process ,adding promoters ,and choosing appropriate catalyst supports. Research progresses in the thermodynamics analyses for steaming reforming of acetic acid are summarized. Further studies should be focused on the effects of a combination of a variety of promoters on carbon deposition. Catalytic activity and the synergy mechanism should be analyzed to produce a novel nickel-based catalyst with high activity ,high resistance to caborn deposition for hydrogen production via steam reforming of bio-oil. Key words :bio-oil ;acetic acid ;hydrogen production ;catalyst ;thermodynamics第一作者:王东旭(1994—),男,硕士研究生,从事生物质能利用技术研究。

棕榈油脱臭馏出物中生育酚及生育三烯酚的富集

棕榈油脱臭馏出物中生育酚及生育三烯酚的富集

收稿日期:2019-06-05;修回日期:2019-07-05作者简介:蒋一鸣(1971),男,工程师,硕士,主要从事油脂副产物综合利用技术研究工作(E-mail )jiangym@cofco.com ;宋佳(1986),女,工程师,硕士,主要从事油脂副产物综合利用技术研究及产品质量管理工作(E-mail )454741824@qq.com 。

蒋一鸣与宋佳并列为第一作者。

应用研究棕榈油脱臭馏出物中生育酚及生育三烯酚的富集蒋一鸣1,宋佳1,史宣明2,曹玉平1,周学晋1,武文华1(1.中粮天科生物工程(天津)有限公司,天津300457;2.西安中粮工程研究设计院有限公司,西安710082)摘要:采用工业化从大豆油脱馏出物中富集维生素E 的工艺,对棕榈油脱臭馏出物中生育酚及生育三烯酚进行了富集。

结果表明,采用酯化、酯交换、一次分子蒸馏、冷析、树脂吸附分离、二次分子蒸馏的工艺,可将棕榈油脱臭馏出物中生育酚及生育三烯酚含量从1.29%浓缩到95%以上,收率可达70%以上。

关键词:棕榈油脱臭馏出物;生育酚;生育三烯酚中图分类号:TS229;TS202.3文献标识码:B文章编号:1003-7969(2019)09-0147-03Enrichment of tocopherol and tocotrienol from palm oil deodorizer distillateJIANG Yiming 1,SONG Jia 1,SHI Xuanming 2,CAO Yuping 1,ZHOU Xuejin 1,WU Wenhua 1(1.COFCO TECH Bioengineering (Tianjin )Co.,Ltd.,Tianjin 300457,China ;2.Xi'an COFCO EngineeringResearch and Design Institute Co.,Ltd.,Xi'an 710082,China )Abstract :The industrial production process of enriching vitamin E from soybean oil deodorizer distillate was carried out to enrich the tocopherol and tocotrienol in palm oil deodorizer distillate.The results showed that the tocopherol and tocotrienol in palm oil deodorizer distillate could be concentrated from 1.29%to over 95%by esterification ,transesterification ,primary molecular distillation ,crystallization ,resin adsorption and secondary molecular distillation.The yield of tocopherol and tocotrienol could reach more than 70%.Key words :palm oil deodorizer distillate ;tocopherol ;tocotrienol 维生素E 是一类具有生物活性、化学结构相似的酚类化合物的总称,包括生育酚(Tocopherol ,T )和生育三烯酚(Tocotrienol ,T 3)。

大学英语四级模拟试卷一及参考答案

大学英语四级模拟试卷一及参考答案

大学英语四级模拟试卷一及参考答案Part I Writing(30 minutes)Directions: For this part, you are allowed 30 minutes to write a composition on the topic Choosing an Occupation. You should write at least 120 words following the outline given below in Chinese:1. 选择职业是一个人要面对的众多难题之一。

2. 需要花时间去选择职业。

3. 选择职业时可以向多人寻求建议和帮助。

Choosing an OccupationPart II Reading Comprehension (Skimming and Scanning)(15 minutes) Directions:In this part, you will have 15 minutes to go over the passage quickly and answer the questions on Answer Sheet 1.For questions 1-7,choose the best answer from the four choices marked[A],[B],[C]and [D]. For questions 8-10,complete the sentences with the information given in the passage.Will We Run Out of Water?Picture a “ghost ship” sinking into the sand, left to rot on dry land by a receding sea. Then imagine dust storms sweeping up toxic pesticides and chemical fertilizers from the dry seabed and spewing them across towns and villages.Seem like a scene from a movie about the end of the world? For people living near the Aral Sea in Central Asia, it’s all too real. Thirty years ago, government planners diverted the rivers that flow into the sea in order to irrigate(provide water for)farmland. As a result, the sea has shrunk to half its original size, stranding ships on dry land. The seawater has tripled in salt content and become polluted, killing all 24 native species of fish.Similar large-scale efforts to redirect water in other parts of the world have also ended in ecological crisis, according to numerous environmental groups. But many countries continue to build massive dams and irrigation systems, even though such projects can create more problems than they fix. Why? People in many parts of the world are desperate for water, and more people will need more water in the nextcentury.“Growing populations will worsen problems with water,” says Peter H. Gleick, an environmental scientist at the Pacific Institute for studies in Development, Environment, and Security, a research organization in California. Hefears that by the year 2025, as many as one third of the world’s projected 8.3 billion people will suffer from water shortages.Where Water GoesOnly 2.5 percent of all water on Earth is freshwater, water suitable for drinking and growing food, says Sandra Postel, director of the Global Water Policy Project in Amherst, Mass. Two-thirds of this freshwater is locked in glaciers and ice caps.In fact, only a tiny percentage of freshwater is part of the water cycle, in which water evaporates and rises into the atmosphere, then condenses and falls back to Earth as precipitation(rain or snow).Some precipitation runs off land to lakes and oceans, and some becomes groundwater, water that seeps into the earth. Much of this renewable freshwater ends up in remote places like the Amazon river basin in Brazil, where few people live.In fact, the world’s population has access to only 12,500 cubic kilometers of freshwater—about the amount of water in Lake Superior. And people use half of this amount already. “If water demand continues to climb rapidly,” says Postel, “t here will be severe shortages and damage to the aquatic environment.”Close to HomeWater woes may seem remote to people living in rich countries like the United States. But Americans could face serious water shortages, too especially in areas that rely on groundwater. Groundwater accumulates in aquifers, layers of sand and gravel that lie between soil and bedrock. (For every liter of surface water, more than 90 liters are hidden underground.)Although the United States has large aquifers, farmers, ranchers, and cities are tapping many of them for water faster than nature can replenish it. In northwest Texas, for example, over pumping has shrunk groundwater supplies by 25 percent, according to Postel.Americans may face even more urgent problems from pollution. Drinking water in the United States is generally safe and meets high standards. Nevertheless, one in five Americans every day unknowingly drinks tap water contaminated with bacteria and chemical wastes, according to the Environmental Protection Agency. In Milwaukee, 400,000 people fell ill in 1993 after drinking tap water tainted with cryptosporidium, a microbe that causes fever, diarrhea and vomiting.The SourceWhere do contaminants come from? In developing countries, people dump raw sewage into the same streams and rivers from which they draw water for drinking and cooking; about 250 millionpeople a year get sick from water borne diseases.In developed countries, manufacturers use 100,000 chemical compounds to make a wide range of products. Toxic chemicals pollute water when released untreated into rivers and lakes. (Certain compounds, such as polychlorinated biphenyls, or PCBs, have been banned in the United States.)But almost everyone contributes to water pollution. People often pour household cleaners, car antifreeze, and paint thinners down the drain; all of these contain hazardous chemicals. Scientists studying water in the San Francisco Bay reported in 1996 that 70 percent of the pollutants could be traced to household waste.Farmers have been criticized for overusing herbicides and pesticides, chemicals that kill weeds and insects but that pollute water as well. Farmers also use nitrates, nitrogen-rich fertilizer that help plants grow but that can wreak havoc on the environment. Nitrates are swept away by surface runoff to lakes and seas. Too many nitrates “over enrich” these bodies of water, encouraging the buildup of algae, or microscopic plants that live on the surface of the water. Algae deprive the water of oxygen that fish need to survive, at times choking off life in an entire body of water.What’s the Solution?Water expert Gleick advocates conservation and local solutions to water-related problems; governments, for instance, would be better off building small-scale dams rather than huge and disruptive projects like the one that ruined the Aral Sea. “More than 1 billion people worldwide don’t have access to basic clean drinking water,” says Gleick. “There has to be a strong push on the part of everyone—governments and ordinary people—to make sure we have a resource so fundamental to life.”1.What caused the Aral Sea to shrink?[A]The rivers flowing into it have been diverted.[B]Farmers used its water to irrigate their farmland.[C]Government planners over-pumped its water.[D]High temperature made its water badly evaporate.2.The construction of massive dams and irrigation projects .[A]does more good than harm[B]solves more problems than what they created[C]does more harm than good[D]brings more water to people than expected3.The chief causes of water shortage include .[A]population growth and water waste[B]water pollution and dry weather[C]water waste and pollution[D]population growth and water pollution4.Americans could suffer from greatly serious water shortages?[A]living in rich areas[B]living in big cities but poor condition[C]depending on groundwater[D]bearing high standards of safe drinking water in mind5.What is the main pollutant in developed countries?[A]Untreated toxic chemicals from manufacturers.[B]Raw sewage into rivers and streams.[C]Herbicides and pesticides used by farmers.[D]Household cleaners poured down the drain.6.How does algae make threats to life of a body of water?[A]By covering the whole surface of the water.[B]By competitively using oxygen life in water needs.[C]By living more rapidly than other life in water .[D]By releasing hazardous chemicals into water.7.According to Gleick, who should be responsible for solving water-related problems?[A]government and housewives.[B]farmers and manufacturers.[C]ordinary people and manufacturers.[D]government and every person.8. According to Peter H. Gleick, by the year 2025, as many as of the world’s people will suffer from water shortages.9.Two thirds of the freshwater on Earth is locked in.10.In developed countries, before toxic chemicals are released into rivers and lakes, they should be treated in order to avoid.Part III Listening Comprehension(35 minutes)Section ADirections: In this section, you will hear 8 short conversations and 2 long conversations. At the end of each conversation, one or more questions will be asked about what was said. Both the conversation and the questions will be spoken only once. After each question there will be a pause. During the pause, you must read the four choices marked [A],[B],[C]and[D], and decide which is the best answer. Then mark the corresponding letter on Answer Sheet 2 with a single line through the centre.11.[A]Wait for the sale to start.[B]Get further information about the sale.[C]Call the TV station to be sure if the ad is true.[D]Buy a new suit.12.[A]He doesn’t think that John is ill.[B]He thinks that perhaps John is not in very good health.[C]He is aware that John is ill.[D]He doesn’t think that John has a very good knowledge of physics.13.[A]Before six.[B]At six.[C]After six.[D]After seven.14.[A]It is bigger.[B]It has a prettier color.[C]It has a larger yard.[D]It is brighter.15.[A]Australian and American.[B]Guest and host.[C]Husband and wife.[D]Professor and student.16.[A]1∶30.[B]11∶00.[C]9∶30.[D]10∶00.17.[A]He prefers staying at home because the bus is too late. [B]He prefers staying at home because he doesn’t like to travel.[C]He prefers taking a bus because the plane makes him nervous.[D]He prefers traveling with the woman.18.[A]He thinks she should visit her cousin. [B]Her cousin doesn’t visit very often.[C]Her cousin is feeling a lot better today.[D]He doesn’t think her cousin has been at home today.Questions 19 to 22 are based on the conversation you have just heard.19.[A]Two different types of bones in the human body.[B]How bones help the body move.[C]How bones continuously repair themselves.[D]The chemical composition of human bones.20.[A]They defend the bone against viruses.[B]They prevent oxygen from entering the bone.[C]They break down bone tissue.[D]They connect the bone to muscle tissue.21.[A]They have difficulty identifying these cells.[B]They aren’t sure how these cells work.[C]They’ve learned how to reproduce these cells.[D]They’ve found similar cells in other species.22.[A]To learn how to prevent a bone disease.[B]To understand differences between bone tissue and other tissue.[C]To find out how specialized bone cells have evolved.[D]To create artificial bone tissue.Questions 23 to 25 are based on the conversation you have just heard.23.[A]A new fuel for buses.[B]The causes of air pollution.[C]A way to improve fuel efficiency in buses.[D]Careers in environmental engineering.24.[A]Her car is being repaired. [B]She wants to help reduce pollution.[C]Parking is difficult in the city.[D]The cost of fuel has increased.25.[A]A fuel that burns cleanly.[B]An oil additive that helps cool engines.[C]A material from which filters are made.[D]An insulating material sprayed on engine partsSection BDirections:In this section, you will hear 3 short passages. At the end of each passage, you will hear some questions. Both the passage and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked [A], [B], [C]and [D].Then mark the corresponding letter on Answer Sheet 2 with a single line through the centre.Passage OneQuestions 26 to 28 are based on the passage you have just heard.26.[A]From three to five months.[B]Three months. [C]Five months.[D]Four months.27.[A]Watch traffic.[B]Obey commands.[C]Cross streets safely.[D]Guard the door.28.[A]Three weeks. [B]Two weeks. [C]Four weeks. [D]Five weeks.Passage TwoQuestions 29 to 31 are based on the passage you have just heard.29.[A]Two to four times.[B]Four to six times.[C]Four to eight times.[D]Six to ten times.30.[A]Sleeping pills made people go into REM sleep quickly.[B]People had more dreams after they took sleeping pills.[C]People became angry easily because they didn’t take sleeping pills.[D]Sleeping pills prevented people from going into REM sleep.31.[A]People dream so as to sleep better.[B]People dream in order not to go into REM sleep.[C]Because they may run into difficult problems in their dreams.[D]Because in their dreams they may find the answers to their problems.Passage ThreeQuestions 32 to 35 are based on the passage you have just heard.32.[A]A sales representative.[B]A store manager.[C]A committee chairperson.[D]A class president.33.[A]To determine who will graduate this year.[B]To discuss the seating arrangement.[C]To choose the chairperson of the ceremonies.[D]To begin planning the graduation ceremonies.34.[A]Their names, phone numbers and job preference.[B]The names and addresses of their guests.[C]The names of the committee they worked on last year.[D]Their dormitory name, address and phone number.35.[A]In an hour.[B]Next week.[C]In one month.[D]Next year.Section CDirections:In this section, you will hear a passage three times. When the passage is read for the first time, you should listen carefully for its general idea. When the passage is read for the second time, you are required to fill in the blanks numbered from 36 to 43 with the exact words you have just heard. For blanks numbered from 44 to 46 you are required to fill in the missing information. For these blanks,you can either use the exact words you have just heard or write down the main points in your own words. Finally, when the passage is read for the third time, you should check what you have written.In the English (36)system, students take three very important examinations. The first is the eleven-plus, which is (37) at the age of eleven or a little past. At one time the (38)or (39) shown on the eleven-plus would have (40)if a child stayed in school. Now, however, all children continue in (41) schools, and the eleven-plus determines which courses of study the child will follow. At the age of fifteen or sixteen, the students are (42)for the Ordinary (43)of the General Certificate of Education. (44). Once students have passed this exam, they are allowed to specialize, so that two thirds or more of their courses will be in physics, chemistry, classical languages, or whatever they wish to study at greater length. (45). Evenat the universities, students study only in their concentrated area, and very few students ever venture out-side that subject again. (46).Part Ⅳ Reading Comprehension(Reading in Depth)(25 minutes)Section ADirections: In this section, there is a passage with ten blanks. You are required to select one word for each blank from a list of choices given in a word bank following the passage. Read the passage through carefully before making your choices. Each choice in the bank is identified by a letter. Please mark the corresponding letter for each item on Answer Sheet 2 with a single line through the centre. You may not use any of the words in the bank more than once.Questions 47 to 56 are based on the following passage.Shopping habits in the United States have changed greatly in the last quarter of the 20th century. Early in the 1900s most American towns and cities had a Main Street. Main Street was always the 47 of a town. This street was lined on the both sides with many48 businesses. Here, shoppers walked into stores to look at all sorts of merchandise: clothing, furniture, hardware, groceries. In addition, some shops offered49 . There shops included drugstores, restaurants, shoe repair stores, and barber or hairdressing shops. But in the 1950s, a change began to50 place. Too many automobiles had crowded into Main Street while too few parking placeswere51 to shoppers. Because the streets were crowded, merchants began to look with interest at the open spaces outside the city limits. Open space is what their car drivingcustomers52 . And open space is what they got when the first shopping centre was built. Shopping centers, or rather malls,53 as a collection of small new stores away from crowded city centers. Attracted by hundreds of free parking space, customers were drawn away from 54areas to outlying malls. And the growing55of shopping centers led in turn to the building of bigger and better stocked stores. By the late 1970s, many shopping malls had almost developed into small cities themselves. In addition to providing the 56 of the stop shopping, malls were transformed into landscaped parks, with benches, fountains, and outdoor entertainment.[A]designed [F]convenience [K]cosmetics[B]take [G]services [L]started[C]heart [H]fame [M]downtown[D]needed [I]various [N]available [C]though [H]popularity [M]cheapnessSection BDirections: There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked [A], [B], [C]and [D].You should decide on the best choice and mark the corresponding letter on Answer Sheet 2 with a single line through the centre.Passage OneQuestions 57 to 61 are based on the following passage.Culture is one of the most challenging elements of the international marketplace. This system of learned behavior patterns characteristic of the members of a given society is constantly shaped by a set of dynamic variables: language, religion, values and attitudes, manners and customs, aesthetics, technology, education, and social institutions. To cope with this system, an international manager needs both factual and interpretive knowledge of culture. To some extent, the factual knowledge can be learned; its interpretation comes only through experience.The most complicated problems in dealing with the cultural environment stem from the fact that one cannot learn culture—one has to live it. Two schools of thought exist in the business world on how to deal with cultural diversity. One is that business is business the world around, following the model of Pepsi and McDonald’s. In some cases, globalizationis a fact of life; however, cultural differences are still far from converging.The other school proposes that companies must tailor business approaches to individual cultures. Setting up policies and procedures in each country has been compared to an organ transplant; the critical question centers around acceptanceor rejection. The major challenge to the international manager is to make sure that rejection is not a result of cultural myopia or even blindness. Fortune examined the international performance of a dozen large companies that earn 20 percent or more of their revenue overseas. The internationally successful companies all share an important quality: patience. They have not rushed into situations but rather built their operations carefully by following the most basic business principles. These principles are to know your adversary, know your audience, and know your customer.57.According to the passage, which of the following is true?[A]All international managers can learn culture.[B]Business diversity is not necessary.[C]Views differ on how to treat culture in business world.[D]Most people do not know foreign culture well.58.According to the author, the model of Pepsi.[A]is in line with the theories that the business is business the world around [B]is different from the model of McDonald’s[C]shows the reverse of globalization[D]has converged cultural differences59.The two schools of thought.[A]both propose that companies should tailor business approaches to individual cultures[B]both advocate that different policies be set up in different countries [C]admit the existence of cultural diversity in business world[D]both A and B60.This article is supposed to be most useful for those.[A]who are interested in researching the topic of cultural diversity[B]who have connections to more than one type of culture[C]who want to travel abroad[D]who want to run business on International Scale61.According to Fortune, successful international companies.[A]earn 20 percent or more of their revenue overseas[B]all have the quality of patience[C]will follow the overseas local cultures[D]adopt the policy of internationalizationPassage TwoQuestions 62 to 66 are based on the following passage.There are people in Italy who can’t stand soccer. Not all Canadians love hockey. A similar situation exists in America, where there are those individuals you may be one of them who yawn or even frown when somebody mentions baseball. Baseball to them means boring hours watching grown men in funny tight outfits standing around in a field staring away while very little of anything happens. They tell you it’s a game better suited to the 19th century, slow, quiet, and gentlemanly. These are the same people you may be one of them who love football because there’s the sport that glorifies “the hit”.By contrast, baseball seems abstract, cool, silent, still. On TV the game is fractured into a dozen perspectives, replays, close-ups. The geometry of the game, however, is essential to understanding it. You will contemplate the game from one point as a painter does his subject; you may, of course, project yourself into the game. It is in this projection that the game affords so much space and time for involvement. The TV won’t do it for you.Take, for example, the third baseman. You sit behind the third base dugout and you watch him watching home plate. His legs are apart, knees flexed. His arms hang loose. He does a lot of this. The skeptic still cannot think of any other sports so still, so passive. But watch what happens every time the pitcher throws: the third baseman goes up on his toes, flexes his arms or brings the glove to a point in front of him, takes a step right or left, backward or forward, perhaps he glances across the field to check his first baseman’s position. Suppose the pitch is a ball. “Nothing happened,” you say. “I could have had my eyes closed.”The skeptic and the innocent must play the game. And this involvement in the stands is no more intellectual than listening to music is. Watch the third baseman. Smooth the dirt in front of you with one foot; smooth the pocket in your glove; watch the eyes of the batter, the speedof the bat, the sound of horsehide on wood. If football is a symphony of movement and theatre, baseball is chamber music, a spacious interlocking of notes, chorus and responses.62.The passage is mainly concerned with .[A]the different tastes of people for sports[B]the different characteristics of sports[C]the attraction of football[D]the attraction of baseball63.Those who don’t like baseball may complain that. [A]it is only to the taste of the old[B]it involves fewer players than football[C]it is not exciting enough[D]it is pretentious and looks funny64.The author admits that.[A]baseball is too peaceful for the young[B]baseball may seem boring when watched on TV[C]football is more attracting than baseball[D]baseball is more interesting than football65.By stating “I could have had my eyes closed.” the author means (4th paragraph last sentence).[A]the third baseman would rather sleep than play the game[B]even if the third baseman closed his eyes a moment ago, it could make no difference to the result[C]the third baseman is so good at baseball that he could finish the game with eyes closed all the time and do his work well[D]the consequence was so bad that he could not bear to see it66.We can safely conclude that the author.[A]likes football[B]hates football[C]hates baseball[D]likes baseballPart Ⅴ Cloze (15 minutes)Directions: There are 20 blanks in the following passage. For each blank there are four choices marked [A], [B], [C]and [D]on the right side of the paper. You should choose the ONE that best fits into the passage. Then mark the corresponding letter on Answer Sheet 2 with a single line through the centre.Who won the WorldCup 1994 football game? What happened at the United Nations? How did the critics like the new play?67 an event takes place, newspapers are on the streets68 the details. Wherever anything happens in the world, reports are on the spot to69 the news. Newspapers have one basic70 , to get the news as quickly as possible from its source, from those who make it to those who want to71 it. Radio, telegraph, television, and 72inventions brought competition for newspapers. So did the development of magazines and other means of communication.73 , this competition merely spurred the newspapers on. They quickly made use of the newer and faster means of communication to improve the74and thus the efficiency of their own operations.Today more newspapers are75 and read than ever before. Competition also led newspapers to branch out to many other fields. Besides keeping readers76 of the latest news, today’s newspapers77 and influence readers about politics and othe r important and serious matters. Newspapers influence readers’economic choices78 advertising. Most newspapers depend on advertising for their very79 . Newspapers are sold at a price that80 even a small fraction of the cost of production. The main81 of income for most newspapers is commercial advertising. The82in selling advertising depends on a newspaper’s value to advertisers. This83 in terms of circulation. How many people read the newspaper? Circulation depends84on the work of the circulation department and on the services or entertainment85 in a newspaper’s pages. But for the most part, circulation depends on a newspaper ’ s value to readers as a source of information 86 the community, city, country, state, nation, and world—and even outer space.67.[A]Just when[B]While[C]Soon after[D]Before68.[A]to give[B]giving[C]given[D]being given69.[A]gather[B]spread[C]carry[D]bring70.[A]reason[B]cause[C]problem[D]purpose71.[A]make[B]publish[C]know[D]write72.[A]another[B]other[C]one another[D]the other73.[A]However[B]And[C]Therefore[D]So74.[A]value[B]ratio[C]rate[D]speed75.[A]spread[B]passed[C]printed[D]completed76.[A]inform[B]be informed[C]to informed[D]informed77.[A]entertain[B]encourage[C]educate[D]edit78.[A]on[B]through[C]with[D]of79.[A]forms[B]existence[C]contents[D]purpose80.[A]tries to cover[B]manages to cover[C]fails to cover[D]succeeds in81.[A]source [B]origin[C]course[D]finance82.[A]way[B]means[C]chance [D]success83.[A]measures[B]measured[C]is measured[D]was measured84.[A]somewhat [B]little[C]much[D]something85.[A]offering[B]offered[C]which offered[D]to be offered86.[A]by [B]with[C]at[D]aboutPart Ⅵ Translation(5 minutes)Direction: Complete the sentences on Answer Sheet 2 by translating into English the Chinese given in brackets.87.There’s a man at the reception desk who seems very angry and I think he means (想找麻烦).88.Why didn’t you tell me you could lend me the money? I (本来不必从银行借钱的).89.(正是由于她太没有经验) that she does not know how to deal with the situation.90.I (将做实验) from three to five this afternoon.91.If this can’t be settled reasonably, it may be necessary to (诉诸武力).参考答案及解析Part I Writing【写作思路】本文是一篇关于择业的议论文。

训诂学 英语

训诂学 英语

训诂学英语The Significance of Etymology in the English LanguageThe study of etymology, the origin and history of words, plays a crucial role in understanding the complexities and nuances of the English language. As an integral part of linguistics, etymology provides valuable insights into the evolution of language, the cultural influences that have shaped it, and the deeper meanings that lie beneath the surface of the words we use daily.One of the primary benefits of studying etymology is the ability to trace the origins of words. By examining the root words, prefixes, and suffixes that make up a term, we can uncover the etymological lineage and gain a deeper appreciation for the word's evolution. This knowledge can be particularly useful when encountering unfamiliar or obscure vocabulary, as it allows us to decipher the meaning based on the word's constituent elements.Moreover, the study of etymology can shed light on the cultural and historical contexts that have influenced the development of the English language. Many words in the English lexicon have their roots in other languages, reflecting the diverse linguistic and culturalinfluences that have shaped the language over time. For instance, the word "restaurant" is derived from the French word "restaurer," meaning "to restore," which reflects the origin of the modern restaurant as a place where weary travelers could restore their strength. Understanding these linguistic connections can provide valuable insights into the cultural exchange and interactions that have occurred throughout history.Beyond the historical and cultural significance, the study of etymology can also enhance our understanding of the nuanced meanings and connotations of words. By tracing the evolution of a word's meaning, we can gain a deeper appreciation for the subtle differences and shades of meaning that exist within the language. This knowledge can be particularly valuable in fields such as literature, where the precise use of language is crucial for conveying complex ideas and emotions.Furthermore, the study of etymology can have practical applications in language learning and acquisition. By understanding the root words and patterns that underlie the English language, students can more effectively learn and retain new vocabulary, as well as develop a better understanding of the language's structure and grammar. This knowledge can also assist in the translation and interpretation of texts, as it allows for a more nuanced understanding of the original meaning and context.In the realm of professional and academic writing, the knowledge of etymology can be a valuable asset. Writers and researchers can use their understanding of word origins to craft more precise and evocative language, selecting words that convey the desired meaning and tone with greater accuracy. This attention to linguistic detail can enhance the clarity, persuasiveness, and overall impact of written communication.Beyond its academic and professional applications, the study of etymology can also be a source of personal enrichment and intellectual curiosity. Exploring the origins and evolution of words can be a fascinating journey, revealing the hidden stories and cultural connections that lie within the language we use every day. This pursuit can foster a greater appreciation for the complexity and beauty of the English language, and inspire a lifelong fascination with the power of words.In conclusion, the study of etymology is a vital component of understanding the English language. By tracing the origins and evolution of words, we can gain valuable insights into the cultural, historical, and linguistic forces that have shaped the language we use today. Whether in the classroom, the workplace, or our personal lives, the knowledge of etymology can enhance our understanding,communication, and appreciation for the richness and nuance of the English language.。

The Chemistry of Green Synthesis and Catalysis

The Chemistry of Green Synthesis and Catalysis

The Chemistry of Green Synthesis andCatalysisIntroductionThe modern world is facing many environmental problems caused by human activities. Environmental pollution, climate change, and depletion of natural resources are the major concerns. To address these issues, scientists are exploring ways to develop sustainable technologies and practices. The field of green chemistry aims to reduce the environmental impact of chemical processes by minimizing waste, using renewable resources, and reducing toxic substances. Green synthesis and catalysis are two important subfields of green chemistry, which have great potential for sustainable development.What is Green Synthesis?Green synthesis refers to the development of chemical reactions that are environmentally benign and sustainable. It involves using renewable resources, reducing the use of hazardous chemicals, and minimizing waste. Green synthesis is important because traditional chemical processes are often resource-intensive, produce large amounts of waste, and use toxic solvents, which can have adverse effects on human health and the environment.Green synthesis can be achieved by several methods, including using bio-based feedstocks, replacing hazardous solvents with benign ones, using microwave or ultrasound-assisted reactions, and using catalysts. Catalysts are an important tool in green synthesis, as they often allow the reaction to proceed more efficiently and with fewer environmental impacts.What is Catalysis?Catalysis is the process of accelerating a chemical reaction by adding a substance known as a catalyst. A catalyst works by lowering the activation energy required for the reaction to occur. It does not affect the thermodynamics of the reaction and is notconsumed in the reaction. Therefore, catalysts can be used repeatedly to speed up reactions without being depleted.Catalysis plays a crucial role in many industrial processes, including the production of fuels, polymers, and pharmaceuticals. However, traditional catalytic processes often use high temperatures and pressures, require toxic solvents, and produce hazardous waste. This is where green catalysis comes in.What is Green Catalysis?Green catalysis is a branch of green chemistry that focuses on developing sustainable catalysts and catalytic processes. Its goal is to reduce the environmental impact of catalytic reactions by using renewable resources, minimizing waste and toxicity, and improving efficiency.Green catalysis has many benefits over traditional catalysis. For example, it can reduce energy consumption and therefore lower greenhouse gas emissions. It can also use non-toxic and renewable resources, which can reduce the environmental impact of the reaction. In addition, green catalysis often uses less hazardous solvents, which improves the safety of the reaction for workers and reduces the risk of contaminated waste.Green Synthesis and Catalysis in ActionThere are many examples of green synthesis and catalysis being used in industrial processes. For example, the production of biodiesel is a green synthesis process that uses vegetable oil or animal fat as a renewable feedstock. The reaction is catalyzed by sodium hydroxide or potassium hydroxide, which are both inexpensive and non-toxic catalysts.Another example is the production of pharmaceuticals using enzyme catalysis. Enzymes are biocatalysts that work under mild conditions of temperature and pressure and produce little or no waste. Their use in the production of pharmaceuticals can reduce the environmental impact of the process and improve the safety for workers.ConclusionGreen synthesis and catalysis are two important subfields of green chemistry that have great potential for sustainable development. By using renewable resources, minimizing waste and toxicity, and improving efficiency, these processes can reduce the environmental impact of chemical reactions. Green synthesis and catalysis are already being used in many industrial processes, and their use is likely to increase in the future as the demand for sustainable technologies and practices grows.。

地球化学资料1

地球化学资料1

地球化学资料1地球化学资料(1120101)第⼀章地球化学定义DefinitionB.И.韦尔纳茨基(1922):地球化学科学地研究地壳中的化学元素(chemical elements),即地壳的原⼦,在可能的范围内也研究整个地球的原⼦。

地球化学研究原⼦的历史、它们在时间和空间上的运动(movement)和分配(partitioning),以及它们在整个地球上的成因(origin)关系。

V.M.费尔斯曼(1922):地球化学研究地壳中化学元素---原⼦的历史及其在⾃然界各种不同的热⼒学(thermodynamical)与物理化学条件(physical-chemical conditions)下的⾏为。

V.M.哥尔德施密特(1933):地球化学是根据原⼦和离⼦的性质,研究化学元素在矿物、矿⽯、岩⽯、⼟壤、⽔及⼤⽓圈中的分布和含量以及这些元素在⾃然界中的迁移。

地球化学的主要⽬的,⼀⽅⾯是要定量地确定地球及其各部分的成分,另⼀⽅⾯是要发现控制各种元素分配的规律(laws governing element distribution and partitioning)。

V.V.谢尔宾娜(1972):研究地球的化学作⽤的科学---化学元素的迁移、它们的集中和分散,地球及其层圈的化学成分、分布、分配和化学元素在地壳中的结合。

(地球化学基础)涂光炽(1985):地球化学是研究地球(包括部分天体celestial bodies)的化学组成(chemical composition)、化学作⽤(chemical process)和化学演化(chemical evolution)的科学。

刘英俊等(1987):地球化学研究地壳(尽可能整个地球)中的化学成分和化学元素及其同位素在地壳中的分布、分配、共⽣组合associations、集中分散enrichment-dispersion及迁移循徊migration cycles规律、运动形式forms of movement和全部运动历史的科学。

【四六级】TPO 07阅读详细解析——【英语阅读提高TPO 阅读详细解析】

【四六级】TPO 07阅读详细解析——【英语阅读提高TPO 阅读详细解析】

TPO 07 Paragraph 11.The wordin thepassage is closest in meaning to○achievement○requirement○purpose○feature2.Which of the following is NOT mentioned in paragraph 1 as a change that occurred in the fauna of the Mediterranean?○Most invertebrate species disappeared during a wave ofextinctions.○A few hardy species wiped out many of the Mediterranean’sinvertebrates.○Some invertebrates migrated to Atlantic Ocean.○New species of fauna populated the Mediterranean whenThe Geologic History ofthe MediterraneanIn 1970 geologists Kenneth J. Hsu and William B.F. Ryan were collecting research data while aboard the oceanographicresearch vessel Glomar Challenger. An of this particular cruise was to investigate the floor of the Mediterranean and to resolve questions about its geologic history. One question was related to evidence that the invertebrate fauna (animals without spines) of the Mediterranean had changed abruptly about 6 million years ago. Most of the older organisms were nearly wiped out, although a few hardy species survived. A few managed to migrate into the Atlantic. Somewhat later, the1the old migrants returned.Paragraph 33.What does the author imply by○The most obvious explanation for the origin of the pebbles was not migrants returned, bringing new species with them. Why did the near extinction and migrations occur?■Another task for the Glomar Challenge r’s scientists was to try to determine the origin of the domelike masses buried deep beneath the Mediterranean seafloor. ■These structures had been detected years earlier by echo-sounding instruments, but they had never been penetrated in the course of dri lling. ■Were they salt domes such as are common along the United States Gulf Coast, and if so, why should there have been so much solid crystalline salt beneath the floor of the Mediterranean? ■With question such as these clearly before them, the scientists2supported by the evidence.○The geologists did not find as many pebbles as they expected.○The geologists were looking for a particular kind of pebble.○The different pebbles could not have come from only one source.4.Which of the following can be inferred from paragraph 3 about the solid gypsum layer?○It did not contain any marine fossil.○It had formed in open-ocean conditions.○It had once been soft, deep-sea mud.○It contained sediment from nearby deserts.5. Select the TWO answer choice from paragraph 3 that identify materials discovered in the deepest part of the Mediterranean basin. To receive credit aboard the Glomar Challenger processed to the Mediterranean to search for the answers. On August 23, 1970, they recovered a sample. The sample consisted of pebbles of gypsum and fragments of volcanicIn the days following, samples of solid gypsum were repeatedly brought on deck as drilling operations penetrated the seafloor. Furthermore, the gypsum was found to possess peculiarities of composition and structure that suggested it had formed on desert flats. Sediment above and below the gypsum layer contained tiny marine fossils, indicating open-ocean conditions. As they drilled into the central and deepest part of the Mediterranean basin, the3you must select TWO answers.○Volcanic rock fragments.○This silt layers○Soft, deep-sea mud○Crystalline salt6. What is the main purpose of paragraph 3?○To describe the physical evidence collected by Hsu and Ryan.○To explain why some of the questions posed earlier in the passage could not be answered by the findings of the Glomar Challenger.○To evaluate techniques used by Hsu and Ryan to explore the sea floor.○To describe the most difficult problems faced by the GlomarChallenger expedition.Paragraph 47. According to paragraph 4, which of the following was responsible for the evaporation of the Mediterranean’s scientists took solid, shiny, crystalline salt from the core barrel. Interbedded with the salt were thin layers of what appeared to be windblown silt.The time had come to formulate a hypothesis. The4waters?○The movements of Earth’s crust○The accumulation of sediment layers○Changes in the water level of the Atlantic Ocean○Changes in Earth’s temperature8. The word “scores” in the passage is closest in meaning to○members○large numbers○populations○different types9. According to paragraph 4, what caused most invertebrate species in the Mediterranean to become extinct?○The evaporation of chemicals necessary for their survival○Crustal movements that connected the Mediterranean to the investigators theorized that about 20 million years ago, the Mediterranean was a broad seaway linked to the Atlantic by two narrow straits. Crustal movements closed the straits, and the landlocked Mediterranean began to evaporate. Increasing salinity caused by the evaporation resulted in the extermination ofof invertebrate species. Only a few organisms especially tolerant of very salty conditions remained. As evaporation continued, the remaining brine (salt water) became so dense that the calcium sulfate of the hard layer was precipitated. In the central deeper part of the basin, the last of the brine evaporated to precipitate more soluble sodium chloride (salt). Later, under the weight of overlying sediments, this salt flowed plastically upward to5saltier Atlantic○The migration of new species through the narrow straits○Their inability to tolerate the increasing salt content of theMediterranean10. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.○The strait of Gibraltar reopened when the Mediterranean and the Atlantic became connected and the cascades of water from one sea to the other caused crustal adjustments and faulting.○The Mediterranean was dramatically refilled by water from the Atlantic when crustal adjustments and faulting opened the Strait of Gibraltar, the place where the two seas are joined.○The cascades of water from the form salt domes. Before this happened, however, the Mediterranean was a vast desert 3,000 meters deep. Then, about 5.5 million years ago came the deluge.tore into the hardened salt flats, broke them up, and ground them into the pebbles observed in the first sample taken by the Challenger. As the basin was refilled, normal marine organisms returned. Soon layer of oceanic ooze began to accumulate above the old hard layer.The salt and gypsum, the faunal changes, and the unusual gravel provided abundant6Atlantic to the Mediterranean were not as spectacular as the crustal adjustments and faulting that occurred when the Strait of Gibraltar was connected to those seas.○As a result of crustal adjustments and faulting and the creation of the Strait of Gibraltar, the Atlantic and Mediterranean were connected and became a single sea with spectacular cascades of water between them.11. The word “Turbulent” in the passage is closest in meaning to○fresh○deep○violent○temperateParagraph 212. Look at the four squares ■ that indicate where the following sentence could be added to the passage.Thus, scientists had information about the shape of the domes but not evidence that the Mediterranean was once a desert.gypsum: a mineral made of calcium sulfate and water7about their chemical composition and origin.Where would the sentence best fit?13.An expedition to the Mediterranean answered some long-standing questions about the ocean’s history.●●●Answer choices1. The Glomar Challenger expedition investigated changes in invertebrate fauna and some unusual geologic features.2. Researchers collected fossils to determine which new species migrated from the Atlantic with older species.3. Scientists aboard the Glomar Challenger were the first to discover the existence of domelike masses underneath the seafloor.4. Samples recovered from the■Another task for the Glomar Challenger’s scientists was to try to determine the origin of the domelike masses buried deep beneath the Mediterranean seafloor. ■These structures had been detected years earlier by echo-sounding instruments, but they had never been penetrated in the course of drilling. ■Were they salt domes such as are common along the United States Gulf Coast, and if so, why should there have been so much solid crystalline salt beneath the floor of the Mediterranean? ■8旗开得胜expedition revealed importantdifferences in chemical composition andfossil distribution among the sedimentlayers.5. Evidence collected by the GlomarChallenger supports geologists' beliefsthat the Mediterranean had evaporatedand become a desert, before it refilledwith water.6. Mediterranean salt domes formedafter crustal movements opened thestraits between the Mediterranean andthe Atlantic, and the Mediterraneanrefilled with water.9旗开得胜10Paragraph 11. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.○The regularity and power of stone walls inspired Romans attempting to unify the parts of their realm.○Although the Romans used different types of designs when building their walls, they used regular controls to maintain their realm.○Several types of control united the Roman realm, just as design and cement held Roman walls together.○Romans built walls to unite the various parts of their realm into a single entity, which was controlled by powerful laws.2. According to paragraph 1, all of the following are controls that held together the roman world EXCEPTAncient Rome and GreeceThere is a quality of cohesiveness about the Roman world that applied neither to Greece nor perhaps to any other civilization, ancient or modern. Like the stone of Roman wall, which were held together both by the regularity of the design and by that peculiarly powerful Roman cement, so the various parts of the Roman realm were bonded into a massive, monolithic entity by physical, organizational, and psychological controls. The physical bonds included the network of military garrisons, which were stationed in every province, and the network of stone-built roads that linked the provinces with Rome. The organizational bonds were based on the common principles of law and administration and on the universal army of officials who enforced common standards of conduct. The psychological controls were built on fear and punishment —on the absolute certainty○administrative and legal systems○the presence of the military○a common language○transportation networksParagraph 23.The phrase “obsession with” in the passage is closest in meaning to○thinking about○fixation on○interest in○attitude toward4.According to paragraph 2, which of the following was NOT characteristic of Rome’s early development?○Expansion by sea invasion○T erritorial expansion○Expansion from one original settlement ○Expansion through invading armies5.Why does the author mention “Alexander the Great” in the passage?○T o acknowledge that Greek civilization that anyone or anything that threatened the authority of Rome would be utterly destroyed.The source of Roman obsession with unity and cohesion may well have lain in the pattern of Rome’s early development. Whereas Greece had grown from scores of scattered cities, Rome grew from one single organism. While the Greek world had expanded along the Mediterranean seas lanes, the Roman world was assembled by territorial conquest. Of course, the contrast is not quite so stark: in Alexander the Great the Greeks had found the greatest territorial conqueror of all time; and the Romans, once they moved outside Italy, did not fail to learn the lessons of sea power. Yet the essential difference is undeniable. The Key to the Greek world lay in its high-11also expanded by land conquest○T o comp are Greek leaders to Roman leaders○T o give an example of Greek leader whom Romans studied○T o indicate the superior organization of the Greek militaryParagraph 36.is closest in meaning to○accepted○combined○introduced○encouraged7.Paragraph 3 suggests which of thefollowing about the people of Latium?○Their economy was based on trade relations with other settlements.○They held different values than the people of Rome.○Agriculture played a significant r ole in the society. powered ships; the key to Roman power lay in its marching legions. The Greeks were wedded to the sea; the Romans, to the land. The Greek was a sailor at heart; the Roman, a landsman.Certainly, in trying to explain the Roman phenomenon, one would have to place great emphasis on this almost instinct for the territorial imperative. Roman priorities lay in the organization, exploitation, and defense of their territory. In all probability it was the fertile plain of Latium, where the Latins who founded Rome originated, that created the habits and skills of landed settlement, landed property, landed economy, landed administration, and a12○They possessed unusual knowledge of animal instinctsParagraph 48.Paragraph 4 indicates that somehistorians admire Roman civilization because of○the diversity of cultures within Roman society○its strength○its innovative nature○the large body of literature that it developed9.In paragraph 4, the author develops adescription of Roman civilization by○comparing the opinions of Roman intellectuals to Greek intellectuals○identifying which characteristics of roman civilization were copied from Greece○explaining how the differences between Roman and Greece developed as time passed○contrasting characteristics of Roman land-based society. From this arose the Roman genius for military organization and orderly government. In turn, a deep attachment to the land, and to the stability which rural life engenders,the Roman virtues: gravitas, a sense of responsibility, peitas, a sense of devotion to family and country, and iustitia, a sense of the natural order.Modern attitudes to Roman civilization range from the infinitely impressed to the thorough disgusted. ■As always, there are the power worshippers, especially among historians, who are predisposed to admire whatever is strong, who feel more attracted to the might of Rome than to the subtlety of Greece. ■At the same time, there is a solid body of opinion that dislikes Rome. ■For many, Rome is at best the imitator and the continuator of Greece on a larger scale. ■Greek civilization had quality; Rome,13civilization with characteristics of Greek civilization10.According to paragraph 4, intellectual Romans such as Horace held which of the following opinions about their civilization?○Ancient works of Greece held little value in the Roman world.○The Greek civilization had been surpassed by the Romans.○Roman civilization produced little that was original or memorable.○Romans valued certain types of innovations that had been ignored by ancient Greeks.Paragraph 5mere quantity. Greece was the inventor; Rome, the research and development division. Such indeed was the opinion of some of the more intellectual Romans.” had the Greeks held novelty in such disdain as we,” asked Ho race in his Epistle, “what work of ancient date would now exist?”Rome’s debt to Greece was enormous. The Romans adopted Greek14Paragraph 611.The wordin thepassage is closest in meaning to○abilities○areas○combinations○models12.Which of the following statements about leading Roman soldiers and statesmen is supported by paragraphs 5 and 6?○They could read and write the Greek language.○They frequently wrote poetry and plays.○They focused their writing on military matters.○They wrote according to the philosophical laws of the Greeks.Paragraph 413.Look at the four squares ■ that religion and moral philosophy. In literature, Greek writers were consciously used as models by their Latin successors. It was absolutely accepted that an educated Roman should be fluent in Greek. In speculative philosophy and the sciences, the Romans made virtually no advance on early achievements.Yet it would be wrong to suggest that Rome was somehow a junior partner in Greco-Roman civilization. The Roman genius was projected into newespecially into those of law, military organization, administration, and engineering. Moreover, the tensions that arose within the Roman state produced literary and artistic sensibilities of the highest order. It was no accident that many leading Roman soldiers and statesmen were writers of high caliber.15indicate where the following sentence could be added to the passage.They esteem symbols of Roman power, such as the massive Colosseum. Where would the sentence best fit?14.The Roman world drew its strength from several important sources●●●Answer choices1. Numerous controls imposed by Roman rulers held its territory together.2. The Roman military was organized differently from older military organizations.3. Romans valued sea power as did the Latins, the original inhabitants of Rome.4. Roman values were rooted in a strong attachment to the land and the stability of rural life.5. Rome combined aspects of ancient Greek civilization with its own contributions in new areas. civilization range from the infinitely impressed to the thorough disgusted. ■As always, there are the power worshippers, especially among historians, who are predisposed to admire whatever is strong, who feel more attracted to the might of Rome than to the subtlety of Greece. ■At the same time, there is a solid body of opinion that dislikes Rome. ■For many, Rome is at best the imitator and the continuator of Greece on a larger scale. ■Greek civilization had quality; Rome, mere quantity. Greece was the inventor; Rome, the research and development division. Such indeed was the opinion of some of the more intellectual Romans.” had the Greeks held novelty in such166. Educated Romans modeled their own literature and philosophy on the ancient Greeks disdain as we,” asked Horace in his Epistle, “what work of ancient date wo uld now exist?”17Paragraph 11.The wordin thepassage is closest in meaning to○emerged○was understood○spread○developed2.According to paragraph 1, why do researchers doubt that agriculture developed independently in Africa?○African lakes and rivers already provided enough food for people to survive without agriculture.○The earliest examples of cultivated plants discovered in Africa are native to Asia.○Africa’s native plants are very difficult to domesticate.○African co mmunities were not large enough to support agriculture.无老师网站:ibtsat3.In paragraph 1, what does theAgriculture, Iron, andthe Bantu PeoplesThere is evidence of agriculture in Africa prior to 3000 B.C. It may have developed independently, but many scholars believe that the spread of agriculture and iron throughout Africa linked it to the major centers of the Near East and Mediterranean world. The drying up of what is now the Sahara desert had pushed many peoples to the south into sub-Sahara Africa. These peoples settled at first in scattered hunting-and-gathering bands, although in some places near lakes and rivers, people who fished, with a more secure food supply, lived in larger population concentrations. Agriculture seems to have reached these people from the Near East, since the first domesticated crops were millets and sorghums whose18author imply about changes in the African environment during this time period?○The climate was becoming milder, allowing for a greater variety of crops to be grown.○Although periods of drying forced people south, they returned once their food supply was secure.○Population growth along rivers and lakes was dramatically decreasing the availability of fish.○A region that had once supported many people was becoming a desert where few could surviveParagraph 24.According to paragraph 2,camels were important because they ○were the first domesticated animal to be introduced to Africa○allowed the people of the West African savannahs to carve out large empires origins are not African but west Asian. Once the idea of plantingtheir own crops, such as certain varieties of rice, and they demonstrated a continued receptiveness to new imports. The proposed areas of the domestication of African crops lie in a band that extends from Ethiopia across southern Sudan to West Africa. Subsequently, other crops, such as bananas, were introduced from Southeast Asia.Livestock also came from outside Africa. Cattle were introduced from Asia, as probably were domestic sheep and goats.19○helped African peoples defend themselves against Egyptian invaders○made it cheaper and easier to cross the Sahara5.According to paragraph 2, which of the following were subjects of rock paintings in the Sahara?○Horses and chariots○Sheep and goats○Hyksos invaders from Egypt○Camels and cattleParagraph 36.What function does paragraph 3 serve in the organization of the passage as a whole○It contrasts the development of iron technology in West Asia and West Africa. Horses were apparently introduced by the Hyksos invaders of Egypt (1780-1560 B.C.) and then spread across the Sudan to West Africa. Rock paintings in the Sahara indicate that horses and chariots were used to traverse the desert and that by 300-200 B.C., there were trade routes across the Sahara. Horses were adopted by peoples of the West African savannah, and later their powerful cavalry forces allowed them to carve out large empires. Finally, the camel was introduced around the first century A.D. This was an important innovation, because the camel’s abilities to thrive in harsh desert conditions and to carry large loads cheaply made it an effective and efficient means of transportation. The camel transformed the desert from a barrier into a still difficult, but more20○It discusses a non-agricultural contribution to Africa from Asia.○It introduces evidence that a knowledge of copper working reached Africa and Europe at the same time.○It compares the rates at which iron technology developed in different parts of Africa.Paragraph 47.The wordin thepassage is closest in meaning to ○fascinating○far-reaching○necessary○temporary8.Theword in thepassage is closest in meaning to ○military○physical○ceremonial accessible, route of trade and communication.Iron came from West Asia, although its routes of diffusion were somewhat different than those of agriculture. Most of Africa presents a curious case in which societies moved directly from a technology of stone to iron without passing through the intermediate stage of copper or bronze metallurgy, although some early copper-working sites have been found in West Africa. Knowledge of iron making penetrated into the forest and savannahs of West Africa at roughly the same time that iron making was reaching Europe. Evidence of iron making has been found in Nigeria, Ghana, and Mali.This technological shift causein the complexity of African societies. Iron21○permanent9.According to paragraph 4, all of the following were social effects of the new metal technology in Africa EXCEPT: ○Access to metal tools and weapons created greater social equality.○Metal weapons increased the power of warriors.○Iron tools helped increase the food supply.○T echnical knowl edge gave religious power to its holders.Paragraph 510.Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.○While American iron makers developed the latest furnaces, African iron makers continued using earlier represented power. In West Africa the blacksmith who made tools and functions. Iron hoes, which made the land more productive, and iron weapons, which made the warrior more powerful, had symbolic meaning in a number of West Africa societies. Those who knew the secrets of making ironand sometimes political power.22techniques.○Africans produced iron much earlier than Americans, inventing technologically sophisticated heating systems.○Iron making developed earlier in Africa than in the Americas because of the ready availability of carbon and iron ore.○Both Africa and the Americas developed the capacity for making iron early, but African metallurgy developed at a slower rate.Paragraph 611.The wordin thepassage is closest in meaning to○afraid of○displaced by○running away from○responding to12.Paragraph 6 mentions all of the following as possiblecauses of theright into the Iron Age, taking the basic technology and adapting it to local; conditions and resources.The diffusion of agriculture and later of iron was accompanied by a great movement of people23“Bantu explosion” EXCEPT○superior weapons○better hunting skills○peaceful migra tion○increased populationParagraph 613.Look at the four squares ■ that indicate where the following sentence could be added to the passage.T hese people had a significant linguistic impact on the continent as well.Where would the sentence best fit?14.Agriculture and iron working probably spread to Africa from neighboring regions.●●●Answer choices who may have carried these innovations. These people probably originated in eastern Nigeria. ■Their migration may have been set in motion by an increase in population caused by a movement ofthe desiccation, or drying up, of the Sahara. ■They spoke a language, prior-Bantu (“Bantu” means “the people”), which is the parent tongue of a language of a large number of Bantu languages still spoken throughout sub-Sahara Africa. Why and how these people spread out into central and southern Africa remains a mystery, but archaeologists believe that their iron weapons allowed them to conquer their hunting-gathering opponents, who still used stone implements. ■Still, the process is uncertain, and peaceful migration—or simply rapid241 .Once Africans developed their own crops, they no longer borrowed from other regions.2. The harshness of the African climate meant that agriculture could not develop until after the introduction of iron tools.3. The use of livestock improved transportation and trade and allowed for new forms of political control.4. As the Sahara expanded, the camel gained in importance, eventually coming to have religious significance.5. The spread of iron working had far-reaching effects on social, economic, and political organization in Africa.6. Today's Bantu-speaking peoples are descended from a technologically advanced people who spread throughout Africa. demographic growth—may have also caused the Bantu explosion. ■25。

应用化学专业英语第一单元The-Roots-Of-Chemistry

应用化学专业英语第一单元The-Roots-Of-Chemistry

The Roots Of ChemistryChemistry can be broadly defines as the science of molecules and their transformations.化学可以广泛地定义为科学的分子和他们的转换。

In contrast to mathematics,chemistry is older than people. 与数学不同,化学比人类更久远。

The appearance of life and people on our planet (earth) is most probably the end result of specific chemical processes .生命的出现和人类生活在我们地球上都最可能是特殊化学过程的结果。

Chemical processes have been present in the lives of people from the dawn of history until the present time .化学过程存从古至今存在人们的生活中。

Initially ,these processes were not under our control 最初,这些过程不受我们的控制,,for instance ,the fermentation of fruit juice,the rotting of meat and fish ,and the burning of wood .例如,果汁的发酵,肉和鱼的腐烂,木材的燃烧。

Later on we learned to control chemical processes and to use them to prepare a variety of different products such as food ,metals ,ceramics and leather .后来,我们学着控制化学过程,用它们来准备一系列不同的产品例如食物。

2023届四川省成都市第七中学高三下学期热身考试英语试题

2023届四川省成都市第七中学高三下学期热身考试英语试题

2023届四川省成都市第七中学高三下学期热身考试英语试题学校:___________姓名:___________班级:___________考号:___________一、阅读理解Summer ProgramsISSOSThe ISSOS summer school program offers high school students the opportunity to combine learning, creative enrichment and action-packed adventure in the historic campus of Yale University. Our three-week program welcomes students from over 60 nationalities, and limits the number of students from one nationality to 10% in order to guarantee a truly international experience.Students choose from a variety of academic and elective subjects and benefit from full activities, cultural trip and workshop program. In addition, students are supervised(指导)by summer school advisors who make sure the summer school is fun and that all students make friends from around the world.Summer Institute for the GiftedThe Summer Institute for the Gifted(SIC) is a program of the AlFS Foundation, a not-for-profit organization. At Yale, SIG offers a 3-week summer academic program for gifted and academically talented students aged 13- 17. At SIC students take 4 classes from the subject areas of STEAM, arts, and recreation.A+Summer ProgramEducation Unlimited is a privately held California Corporation with the mission of giving every high school student the best possible chance of gaining acceptance into the college of their choice.Their unique summer offerings include the A + Summer Program hosted at Yale, which is a one-of-a-kind opportunity to be involved in an environment that encourages advanced thinking, creative problem solving, and a lifelong love of learning.Capitol DebateThe 2023 Summer Debate Camp will be held at Yale University from June 28 to July 9. Students will build public speaking, research, writing, and critical thinking skills, leading to better academic performance. The two-week program will provide students with the proper mindset, skillset, toolset and critical communication skills needed for success in many fieldsof speech.1.What can people do in ISSOS summer school program?A.Lear to speak a foreign language.B.Make friends with native students.C.Engage in cultural and academic activities.D.Take elective courses given by supervisors.2.Which program can help students gain admission into university?A.ISSOS summer school program.B.A+Summer Program.C.Summer Institute for the GiftedD.Capitol Debate.3.What do the listed summer programs have in common?A.They target at undergraduates.B.They last for the whole summer.C.They focus on academic lectures.D.They are hosted at Yale University.I never imagined that someone telling me I looked skinny would anger me. And yet, I was made very angry when a colleague pinched (捏) my waist and screamed, “Rosa, you’ve lost weight. You look great!” The truth is that I was tired and not taking care of myself. I decided to start a proper weight-loss program.The first to go would be road rage (路怒). I am in far less control of this weight than any other. Every time something gets in the way, I fly off the handle. I need to lose the road rage! No, no more speed. Instead, I now repeat the words, “I am not in a hurry.” This year, I will drive safely, allowing the “stupid” to happen all around me. From that, I hope to gain patience.Next is guilt. When guilt drives my conscience to do better, it’s functional. But when it presents itself as an internal dialogue that goes nowhere, it’s useless. This year, I want to stop feeling guilty for not keeping a cleaner house, for spending time away from my children to be with friends, for not attending every party because I’d rather be at home, or for watching TV when I should be reading. My image and performance are not at the back of anyone else’s mind but my own. From this, I hope to gain freedom to be myself.The last is fear. Fear has held me back. Fear of failure has prevented me from being a writer. Fear of embarrassment has prevented me from giving an opinion. Fear of being rejected has stopped me from aiming higher in my life. Fear of regret has led me into situations that made me uncomfortable. If I can lose any one of these fears, I stand to gain experience.So, if I can lose the rage, shake off some guilt, and take fear off my plate, I stand to gain patience, freedom, and experience. Pound for pound I have not lost a thing but I will be much lighter. Next time, I hope my colleague looks me in the eye to see my glow instead of pinching part of me that has nothing to do with how great I really look.4.What does the underlined part “fly off the handle” in Paragraph 2 probably mean? A.Pick up speed.B.Drive off.C.Desert the car.D.Lose control of anger.5.What has made the author feel guilty before?A.Attending too many parties.B.Reading much with her children.C.Wasting her time in watching TV.D.Spending little time with her friends.6.How has fear affected the author?A.It has prevented her achieving her goals.B.It has made situations complicated for her.C.It has stopped her furthering her education.D.It has made it difficult for her to make friends.7.Which of the following may be the best title?A.Stop Body Shaming B.Lighten You MindC.Watch Your Weight D.Avoid Body ContactIs it true that our brain alone is responsible for human cognition (认知)? What about our body? Is it possible for thought and behaviour to originate from somewhere other than our brain? Psychologists who study Embodied Cognition (EC) ask similar questions. The EC theory suggests our body is also responsible for thinking or problem-solving. More precisely, the mind shapes the body and the body shapes the mind in equal measure.If you think about it for a moment, it makes total sense. When you smell something goodor hear amusing sounds, certain emotions are awakened. Think about how newborns use their senses to understand the world around them. They don’t have emotions so much as needs — they don’t feel sad, they’re just hungry and need food. Even unborn babies can feel their mothers’ heartbeats and this has a calming effect. In the real world, they cry when they’re cold and then get hugged. That way, they start to associate being warm with being loved.Understandably, theorists have been arguing for years and still disagree on whether the brain is the nerve centre that operates the rest of the body. Older Western philosophers and mainstream language researchers believe this is fact, while EC theorises that the brain and body are working together as an organic supercomputer, processing everything and forming your reactions.Further studies have backed up the mind-body interaction. In one experiment, test subjects were asked to judge people after being handed a hot or a cold drink. They all made warm evaluations when their fingertips perceived warmth rather than coolness. And it works the other way too. In another study, subjects’ fingertip temperatures were measured after being “included” in or “rejected” from a group task. Those who were included felt physically warmer.For further proof, we can look at the metaphors (比喻) that we use without even thinking.A kind and sympathetic person is frequently referred to as one with a soft heart and someone who is very strong and calm in difficult situations is often described as solid as a rock. And this kind of metaphorical use is common across languages.Now that you have the knowledge of mind-body interaction, why not use it? If you’re having a bad day, a warm cup of tea will give you a flash of pleasure. If you know you’re physically cold, warm up before making any interpersonal decisions.8.According to the author, what is the significance of EC?A.It brings us closer to the truth in human cognition.B.It offers a clearer picture of the shape of human brain.C.It reveals the major role of the mind in human cognition.D.It facilitates our understanding of the origin of psychology.9.Where does the newborns’ understanding of their surroundings start from?A.Their personal looks.B.Their mental needs.C.Their inner emotions.D.Their physical feelings.10.What does the author intend to prove by citing the metaphors in Paragraph 5?A.Human speech is alive with metaphors.B.Human senses have effects on thinking.C.Human language is shaped by visual images.D.Human emotions are often compared to natural materials.11.What is the author’s purpose in writing the last paragraph?A.To deepen the readers’ understanding of EC.B.To encourage the reader to put EC into practice.C.To guide the reader onto the path to career success.D.To share with the reader ways to release their emotions.When I mentioned to some friends that we all have accents, most of them proudly replied, “Well, I speak perfect English/Chinese/etc.” But this kind of misses the point.More often than not, what we mean when we say someone “has an accent” is that their accent is different from the local one, or that pronunciations are different from our own. But this definition of accents is limiting and could give rise to prejudice. Funnily enough, in terms of the language study, every person speaks with an accent. It is the regular differences in how we produce sounds that define our accents. Even if you don’t hear it yourself, you speak with some sort of accent. In this sense, it’s pointless to point out that someone“has an accent“. We all do!Every person speaks a dialect (方言), too. In the field of language study, a dialect is a version of a language that is characterized by its variations of structure, phrases and words. For instance,” You got eat or not? “(meaning “Have you eaten?” ) is an acceptable and understood question in Singapore Oral English. The fact that this expression would cause a standard American English speaker to take pause doesn’t mean that Singapore Oral English is “wrong” or “ungrammatical”. The sentence is well-formed and clearly communicative, according to native Singapore English speakers’ solid system of grammar. Why should it be wrong just because it’s different?We need to move beyond a narrow conception of accents and dialects — for the benefit of everyone.Language differences like these provide insights into people’s cultural experiences and backgrounds. In a global age, the way one speaks is a distinct part of one’s identity. Most people would be happy to talk about the cultures behind their speech. We’d learn more aboutthe world we live in and make friends along the way.12.What does the author think of his/ her friends’ response in paragraph 1?A.It reflects their self confidence.B.It reflects their language levels.C.It misses the point of communication.D.It misses the real meaning of accents.13.Why does the author use the example of Singapore Oral English?A.To justify the use of dialects.B.To show the diversity of dialects.C.To correct a grammatical mistake.D.To highlight a traditional approach.14.What does the author recommend us to do in the last paragraph?A.Learn to speak with your local dialect.B.Seek for an official definition of accents.C.Appreciate the value of accents and dialects.D.Distinguish our local languages from others’.15.What can be a suitable title for this passage?A.Everyone Has an AccentB.Accents Enhance Our IdentitiesC.Dialects Lead to MisunderstandingD.Standard English Is at Risk二、七选五You know you really want to do well in your study. Your parents have put the pressureproblem? The following tips may give you a hand.Find a place that makes you want to study. If the books and seriousness of the library put you in the mood for focusing on study, go for it. If the comfortable chairs and coffee at your local café are what you need to get through your reading for English, go there. 17 Set a study schedule. When you have many subjects to study, it can seem hard to get through everything. Give yourself a schedule where you set specific times to study particularsubjects. 18 Besides, change subjects every two hours. A little variety keeps you refreshed and focused.19 If you find yourself distracted from studying by thoughts about something else, spend 5 minutes thinking about them, but then tell yourself studying is your main task now. If you are tired of study, step away from it. A short break helps refresh you so that you can stay focused when you come back to studying.Turn off the electronic devices. Texting, social media, calls and other distractions that come from your electronic devices are some of the biggest barriers to staying focused when you are studying. 20 Turn off the distracting electronic devices!A.Give yourself a brief study break.B.Get yourself clear about the study task.C.But you keep getting distracted!D.Luckily, the fix is easy and totally within your control.E.There’s no doubt that a library is the best place for studying well.F.This makes studying seem less difficult, helping you stay on task.G.The most important thing is that the location motivates you to study.三、完形填空health wasn’t the only 34 of the class. During breaks, people often chatted about family news. Some 35 shared their nearby bird sightings. Whenever people were 36 , we asked around. We signed get-well cards for those who were ill and sympathy cards for those who had 37 loved ones.As I’d hoped, I’m in better 38 now than when I started. But the 39 gift of joining the aerobics class is gaining new 40 and feeling more connected to my local community.21.A.visited B.called C.examined D.told 22.A.cautiously B.punctually C.impatiently D.enthusiastically 23.A.passed by B.broke into C.stared at D.headed for 24.A.greeted B.treated C.stopped D.accompanied 25.A.boring B.creative C.strange D.familiar 26.A.limited B.reduced C.set D.applied 27.A.recommended B.selected C.composed D.recognized 28.A.hits B.plays C.films D.musicals 29.A.entertainment B.workout C.performance D.competition 30.A.fed up B.cast off C.woke up D.cut down 31.A.amused B.hooked C.puzzled D.convinced 32.A.ranged B.ranked C.listed D.divided 33.A.command B.interpretation C.assistance D.trouble 34.A.lesson B.type C.focus D.attention 35.A.still B.even C.almost D.just 36.A.absent B.free C.busy D.glad 37.A.missed B.lost C.ignored D.hurt 38.A.preparation B.protection C.shape D.touch 39.A.unknown B.undesired C.unpacked D.unexpected 40.A.friendship B.independence C.experience D.reputation四、用单词的适当形式完成短文阅读下面短文,在空白处填入1个适当的单词或括号内单词的正确形式。

国庆节英语介绍短文超长版

国庆节英语介绍短文超长版

国庆节英语介绍短文超长版篇1National Day is a significant and joyous occasion in the history of our country. It marks the beginning of a new era and the liberation of the people. The origin of National Day can be traced back to the momentous events that led to the founding of the People's Republic of China.In 1949, after years of arduous struggle and sacrifice, the Chinese people finally achieved victory. The establishment of New China was a turning point that filled the hearts of every citizen with hope and pride! How could we forget those crucial moments? The heroic efforts of countless individuals, their unwavering determination and spirit of self-sacrifice, paved the way for our present and future.Over the years, the celebration of National Day has undergone remarkable changes and enrichment. In the early days, it might have been simple parades and gatherings. But as time went on, it has evolved into a grand spectacle. There are magnificent fireworks displays that light up the night sky, colorful cultural performances that showcase the diversity and unity of our nation, and various exhibitions that tell the story of our progress and achievements.Today, National Day is not just a day of celebration; it is a reminder of our past, a recognition of our present, and a promise for the future. Itbrings people from all walks of life together, united in their love and dedication to the country. Isn't it amazing to see how far we have come? Let us continue to strive for a better tomorrow on this special day and always!篇2National Day is a significant event that holds immense importance for every citizen of a country. It is not merely a day of celebration but a symbol of unity, progress, and national pride.Think about it! Every year on this special day, people come together, hearts filled with joy and a sense of belonging. It serves as a reminder of the hard work and sacrifices made by our forefathers to build a prosperous and peaceful nation. How inspiring is that?The sense of national pride that National Day evokes is truly remarkable. It makes us stand tall and be proud of our rich history, diverse culture, and remarkable achievements. We look back at our journey and marvel at how far we have come. Isn't it a cause for celebration and gratitude?Moreover, National Day has a profound impact on the economy. During this period, there is a boost in domestic tourism. People travel within the country, spending money and contributing to local businesses. This not only promotes economic growth but also strengthens the bonds between different regions. Isn't it wonderful how a single day can havesuch a positive effect on the economy?In terms of cultural exchange, National Day provides a platform for people to showcase and share their unique traditions and customs. It allows for a greater understanding and appreciation of the diversity within our nation. We get to experience different cultures, foods, and art forms. How amazing is it to have such an opportunity to broaden our horizons and celebrate our unity in diversity?In conclusion, National Day is much more than just a holiday. It is a day that unites us, fills us with pride, and drives our nation forward. Let us cherish and celebrate this day with all our hearts, for it is a testament to our collective strength and the bright future that lies ahead!篇3During the National Day, the entire country is immersed in an atmosphere of joy and celebration! It is a time when the nation comes together to showcase its prosperity and unity.The grand military parade is undoubtedly one of the most spectacular events. The neatly arranged troops, the advanced weapons and equipment, all these demonstrate the powerful strength of our country. How magnificent it is! How proud we are! The soldiers' firm steps and resolute expressions seem to tell the world that our country is strong and unbeatable.The rich and varied artistic performances are also very eye-catching. The stage is full of brilliant lights and wonderful music. Dancers show theirgraceful postures, and singers sing passionate songs. Isn't it a wonderful feast for the eyes and ears? These performances not only bring joy to people but also convey the spirit and culture of our nation.In different regions, there are various unique ways of celebration. In some places, there are large-scale folk dance performances. The colorful costumes and vigorous dances reflect the local customs and traditions. In other places, there are magnificent fireworks displays. The night sky is illuminated by brilliant fireworks. How beautiful and breathtaking it is!All these celebrations show that our country is making continuous progress and development. We are proud of our motherland and look forward to its brighter future. Let's celebrate this great festival together and work hard for a better tomorrow of our country!篇4National Day is a significant and remarkable event that holds great influence and prestige on the global stage. It is not just a celebration within the boundaries of China, but a phenomenon that attracts the attention and interest of people from all over the world.Each year, as the date of National Day approaches, the anticipation builds up. The streets and cities of China are adorned with colorful decorations and flags, creating a festive atmosphere that is simply contagious. This vibrant and joyous scene not only delights the hearts of the Chinese people but also beckons foreign tourists to come andexperience the unique charm of this special occasion. They are drawn by the warmth and excitement, eager to immerse themselves in the rich cultural traditions and the spirit of unity that permeates the air.Countless foreign tourists flock to China during this period, marveling at the grand parades, spectacular fireworks, and various cultural performances. They are astounded by the scale and splendor of the celebrations, and they carry back with them memories that last a lifetime. Isn't it wonderful how a single event can bridge the gap between nations and cultures?Moreover, the attention and congratulatory messages from other countries further emphasize the significance of China's National Day. Diplomatic envoys convey their best wishes, and international media cover the event extensively. This shows that China's progress and achievements on this day are recognized and respected by the global community. How amazing is it to see such widespread recognition and appreciation?In conclusion, China's National Day is not just a domestic celebration; it is a global spectacle that showcases the nation's strength, unity, and rich cultural heritage. It serves as a reminder of the remarkable journey China has undertaken and the bright future that lies ahead. So, let us celebrate this glorious day with pride and enthusiasm!篇5National Day is not just a celebration; it is a moment of reflection, atime to look back on the journey a nation has taken and to envision the path ahead. It is a day when the entire country comes together, united by a sense of pride and belonging.Think about it! How does this annual event bring people from all walks of life, from different regions and backgrounds, under one banner? It's the power of shared history, values, and aspirations. The parades, the fireworks, the cultural shows - they aren't just spectacles; they are manifestations of the collective spirit that drives a nation forward.Isn't it remarkable how National Day serves as a reminder of past achievements? It instills in us a sense of confidence and determination to overcome future challenges. But the question is, how do we translate this spirit into concrete actions for the betterment of our country?We can use this occasion to foster unity and cooperation. By coming together, we can pool our resources and talents to address pressing issues such as environmental protection, social equality, and technological innovation. Isn't it inspiring to think that through collective efforts, we can build a more prosperous, sustainable, and inclusive society?Let's not forget the role of education on National Day. It's a perfect opportunity to teach future generations about the significance of our history and the responsibilities they bear. This will ensure that the spirit of National Day lives on and continues to inspire.So, as we celebrate National Day, let's not just enjoy the festivities.Let's use this moment to recommit ourselves to the progress and development of our nation. Let's ask ourselves: What can I do to contribute? How can we, as a nation, keep moving forward? The future is ours to shape, and National Day gives us the impetus to do just that!。

山东省部分名校2024届高三下学期2月大联考英语试卷(含答案)

山东省部分名校2024届高三下学期2月大联考英语试卷(含答案)

山东省部分名校2024届高三下学期2月大联考英语试卷学校:___________姓名:___________班级:___________考号:___________一、阅读理解2024 Hot List: The Best New Restaurants in the World Restaurants are some of the most amazing destinations around the whole world. Here are some of the best for you to have a unique eating experience.Place des Fêtes —New York CityThis famous wine bar provides a spot with a rare sweet and warm atmosphere. For date night, go to the bar with views of the open kitchen, or fill up the large table in the back with a group and taste the entire 20-item menu. Either way, do not miss the famous mushroom soup. Le Doyenné—Saint-Vrain, FranceAustralian chefs James Henry and Shaun Kelly transformed the former stables(马厩)of a 19th-century private estate(庄园)into a working farm, restaurant, and guesthouse driven by the principles of regenerative agriculture. More than one hundred varieties of fruits, vegetables, and herb s make their way into Henry’s cooking after being carefully nurtured by Kelly.Mi Compa Chava —Mexico CitySeafood is a hangover cure in Mexico, and almost everyone eating here is devoted to fixing last night’s damage from drunkenness and getting a head start on creating today’s. On the sidewalk, crowds of locals and tourists alike line up for fisherman Salvador Orozco’s creative takes on Sinalo a and Baja seafood. Anything from the raw half of the menu is a sure bet, though cooked dishes like fish can help fill out a meal.Vilas—BangkokCan a dish inspired by a Spanish recipe using Japanese ingredients(原料)still be considered Thai? For Chef Prin Polsuk, one of Bangkok’s most famous Thai chefs, it most certainly can. At his latest restaurant, a small dining r oom at the base of Bangkok’s landmark King Power Mahanakho n Tower, he draws inspiration from King Chulalongkorn’s 1897 journey around Europe and the foreign ingredients and cooking techniques he added to the royal cookbooks.1.Which of the following restaurants follows the principle of regenerative agriculture?A. Place des Fêtes.B. Le Doyenné.C. Mi Compa Chava.D. Vilas.2.What does the fisherman Salvador Orozco specialize in?A. Delicious seafood soup.B. Distinct foreign flavors.C. Innovative seafood cooking.D. A treatment for drunkenness.3.Where does the text probably come from?A. A travel magazine.B. A scientific report.C. An advertisement.D. A textbook.Recently, a set of video clips (片段) featuring a man showcasing umbrellas with various creative designs has gone viral on the Internet, even spreading overseas and attracting foreign netizens with the unimaginable “Chinese creativity”, CCTV news reported.In the clips, there are shining laser (激光) reflective umbrellas to dispel darkness, umbrellas with floor-length plastic curtains to prevent one’s clothes from getting wet, twin umbrellas specially designed for couples and many others. All of them are made by the man in the clips, Lei Penglin. 38-year-old Lei has operated an umbrella factory in Shaoxing, Zhejiang Province. Netizens affectionately call him “uncle” due to his performances in the clips.In 2014, Lei established his own factory. At first, his factory received thousands of orders. However, as the competition intensified, Lei had to explore new opportunities. He found thatinto the products and, in 2022, his umbrella with an attached flashlight gained popularity. “Consumers pursue person alized products. So the umbrellas have to function as decorations aside from just preventing sunshine and rain,” Lei said.In the comment section of the product videos, Lei noticed an interesting request with many likes, suggesting to him to make a reflective umbrella for walking in the dark. Following the advice, Lei created the “laser reflective umbrella”, selling over 70,000 units once upon release. From then on, Lei started to attach great importance to comments to absorb new ideas.Presently, Lei spend s several hours reading comments every day. “Basically 300 to 500 comments a day, I will read and reply to them all by myself. Only by carefully observing can I know everyone’s need, and solve the after-selling problems on time,” he said. Several products developed based on the comments have been on shelf. “Almost all the umbrellas made so far can be sold; none have suffered loss,” Lei introduced.In the future, Lei hopes to make some Chinese-style umbrellas that can be paired with Han-style clothing. “I want to try something new and also advocate for our Chinese culture,”Lei added.4.What is the feature of Lei’s umbrellas?A. Conventional.B. Innovative.C. Unimaginative.D. Durable.5.What does the underlined word “infuse” in paragraph 3 mean?A. Divide.B. Burst.C. Integrate.D. Emerge.6.What is Lei’s attitude towards his future career?A. Uncertain.B. Indifferent.C. Dissatisfied.D. Optimistic.7.What contributes most to Lei’s success according to the author?A. Promoting his products through social media.B. Paying attention to customers’ comments and needs.C. Seeking uniqueness to compete with other producers.D. Adding elements of traditional culture to his products.Fountains of lava erupted from the Sundhnúkur volcanic system in southwest Iceland on January 14th, 2024. Lava flows welled up from a new gap, attacking the suburbs of Grindavík with at least three houses in their path burnt down. Nearby, construction vehicles that had been working for weeks to build large earthen dams in an attempt to divert(使转向)the lava’s flow had to pull back.Lava is subject to gravity like other fluids, so it will flow down along a path of steepest descent(斜坡). With the temperature of its molten rock often well above 1,000 degrees Celsius, not much can stand in its way. Humans have tried many ways to stop lava in the past, from attempting to freeze it in place by cooling it with sea water, to using explosive s to cut off its supply. However, no attempt was successful.Most recent efforts have focused instead on building dams in an attempt to divert the lava’s flow toward a different path of steepest descent into a different “lavashed,” where lava would naturally flow. Results have been mixed, but diversion can be successful if the lava flow can be clearly diverted into a distinct area where lava would naturally flow — without threatening a different community in the process. Many attempts to divert lava have failed, however. Barriers built in Italy to stop Mt. Etna’s lava flows in 1992 slowed the flow, but the lava eventually over topped each one.Diverting lava in Grindavík is difficult, in part because the land around Grindavík is relatively flat, making it harder to identify a clear alternative path of steepest descent for redirecting the lava. Icelandic official s reported on January 15th that most of the lava from the main fissure had flowed along the outside the barrier, however a new gap had also openedinside the perimeter(外围), sending lava into a neighborhood. Unfortunately, that implies that Grindavík remains at risk.8.What do we know about the lava erupting from the Sundhnúkur volcanic system?A. It severely affected the downtown area of Grindavík.B. It forced the construction of large earthen dams to suspend.C. It was successfully redirected by the earthen barriers:D. It completely buried a residential area.9.How many ways are mentioned to stop the lava?A. Five.B. Four.C. Three.D. Two.10.The lava flow in Grindavík remains a risk because ________.A. the lava has destroyed many buildingsB. there is no suitable dam to divert the lavaC. the land around Grindavík is relatively flatD. the lava has already entered a populated area11.What is the text mainly about?A. How earthen barrier functions.B. What can be done to prevent lava.C. Why volcanic lava is so hard to stop.D. What lava has brought about in Iceland.At ancient sites across the Amazon River basin, mysterious plots of unusually rich soil dot (点缀) the landscape. Scientists have long debated the origin of this “dark earth”, which is darker in color than surrounding soils and richer in carbon. Some people think this dark earth formed naturally, but the latest research has shown that modern Kuikuro people in Brazil create similar soil around their villages on purpose, which adds evidence to the idea that long-ago Amazons deliberately made such soil too. Perron, an earth scientist at MIT, reviewed interviews of Kuikuro people conducted by a Kuikuro filmmaker in 2018 and found that Kuikuro villagers actively make dark earth by using ash, food bits and controlled burns. “When you plant in hilly land, the soil is weak,” explained elder Kanu Kuikuro in one of the interviews. That is why we throw the ash, manioc peelings and manioc pulp. When comparing soil samples from ancient and modern sites, resear chers found “striking similarities” — both were far less acidic than surrounding soils and contained higher levels of plant-friendly nutrients.Analyses also revealed that dark earth holds twice the amount of carbon as surrounding soils on average. Scans (扫描) of the Xingu region suggest that the area is dotted with dark earth, and that hold as much as about 9 million tons of carbon — the annual carbon emissionsof a small, industrialized country. “This number could roughly equal the annual carbon emissions of the United States when all dark earth across the Amazon is taken into consideration,” Perron says.Figuring out the true value of carbon stored in the Amazon’s dark earth will require more data. Still, the research has significant influences on the Amaz on’s future. The technique highlights how ancient people were able to live in the Amazon by developing sustainable farming that doubled as a carbon-storing technique. With more and more greenhouse gases entering the atmosphere, it could also provide a blueprint for developing methods of sustainably locking atmospheric carbon in the soil, helping fight climate change.12.What can we infer from the dark earth across the Amazon River basin?A. They are more acidic than surrounding soils.B. They contain more organic nutrients.C. They formed naturally.D. They contain less carbon.13.Why does the author mention the annual carbon emissions of the US?A. To explain the difficulty of protecting dark earth.B. To show the wide distribution of dark earth in Amazon.C. To stress the huge carbon-storing capability of dark earth.D. To reveal the large carbon emissions of the United States.14.What does the author stress in the last paragraph?A. The importance of developing sustainable farming.B. The advanced farming technology in ancient tomes.C. A possible solution to climate change.D. A way of green agriculture.15.Which is the best title of the text?A. Urgency of Sustainable DevelopmentB. Facts About the Dark EarthC. Advantages of the Dark EarthD. Wisdom of Ancient Amazons二、七选五16.“Second place is just the first loser.” is a well-known saying from the NASCAR champion Dale Earnhardt.We may not want others to know our thoughts, but many of us think this way, because we are born to compete with each other. ①________ Fortunately, there is a way to solve this problem: instead of always going for gold, aim for the bronze.To expand on the wisdom of Earnhardt, although second place may be the first loser, third place can be the real winner, at least when it comes to happiness and longevity. A 1995 study discovered that bronze winners appeared consistently happier on average than silver medalists, while another research in 2018 studied US athletes in the Olympics from 1904 to 1936 and found that those whose best performance was silver lived to 72 on average. Gold medalists beat this by living to 76. ②________③________ Silver medalists see themselves as the first loser because they compare themselves only with the champions. In contrast, the bronze winners compare downwards with those who have never made it onto the podium at all. ④________ The emotion shows up in improved health and longevity.The worldly happiness strategy of working for gold every day is foolish. Stop spending most of your time feeling like a silver medalist: always pursuing and relying your happiness on a single outcome. ⑤________A. But the first prize went to the bronze winners, who lived to 78.B. Therefore, they feel better about themselves and thus, happier.C. However, if left uncontrolled, this can create conflicts between ourselves and others.D. The social concepts of upward and downward comparison help explain the difference.E. The comparison is not from a feeling of ill will, but because rewards in life are relative.F. Comparing ourselves with the unlucky is a reliable technique for reducing a negative mood.G. Rather, aim for health y competitions where you do your best without expecting to be the absolute winner.三、完形填空(15空)Ashoka, an association founded by Bill Drayton, has fought to end poverty (贫困) and sickness, promoted education and encouraged small businesses. To support these worthyimprove social conditions. An excellent example is an Ashoka project started in 1995 inan income for local farmers there.When Masqsood and Iftekhar from Ashoka began to study the problem of all thepractical progress in bringing about social change by changing the way we look at economic development.17.A. plans B. causes C. attempts D. events18.A. right B. confidence C. permission D. praise19.A. in particular B. in fact C. on purpose D. in turn20.A. avoid B. decline C. accept D. appreciate21.A. professional B. generous C. contributing D. innocent22.A. ambition B. definition C. advice D. purpose23.A. water B. resource C. rubbish D. traffic24.A. attacking B. charging C. counting D. inviting25.A. employ B. create C. leave D. send26.A. hope B. market C. desire D. way27.A. expensive B. effective C. affordable D. profitable28.A. refused B. recognised C. confused D. surprised29.A. permit B. order C. advise D. persuade30.A. set off B. took off C. picked up D. put up31.A. uncertain B. doubtful C. pessimistic D. optimistic四、短文填空32.What’s the first thing ①________ comes into your mind when you think of w heat straw (麦秆)? Most people would probably just see it as a pile of waste in a farmer’s field. However, WuCui, an intangible (非物质的) cultural inheritor, can turn the straw into beautiful and eye-catching ②________ (function) artworks.The earliest straw-weaving products ③________ (discover) at Hemudu Cultural Ruins, a Neolithic cultural site located in eastern China’s Zhejiang Province. The Book of Rites, one ofthe classical ④________ (work) of Confucianism, also records that there were already mats made of cattail grass and professional straw-weaving craftsmen during the Zhou Dynasty. Straw weaving was listed ⑤________ a national intangible cultural heritage in 2008.Straw weaving is a time-consuming process that can take weeks, ⑥________ even months, to complete. Later, industrial goods have taken ⑦________ place of such products, which make low profits, and there are only about 100 individuals ⑧________ (involve) in the work across the country. “The world has changed, and craftsmen need to overstep practicality and pursue the beauty and artistry of straw culture ⑨________ (help) the craft survive and thrive,” Wu says.From her viewpoint, straw weaving should respond to people’s needs and preferences, while still ⑩________ (draw) inspiration from traditional culture.五、书面表达33.上周五晚上你校邀请了一位心理学专家做了一个主题为“珍爱生命,直面挫折”的心理健康讲座活动。

传统音乐鉴赏英语作文初一

传统音乐鉴赏英语作文初一

传统音乐鉴赏英语作文初一传统音乐鉴赏。

Music is an integral part of human culture, withdiverse genres reflecting various cultures and traditions. Traditional music, in particular, holds a special place in preserving heritage and expressing the essence of a society. In this essay, we will delve into the realm of traditional music appreciation, exploring its significance, characteristics, and the profound impact it has on individuals and communities.To appreciate traditional music effectively, one must first understand its historical and cultural context. Traditional music often originates from specific regions or communities and is passed down through generations orallyor through written scores. It embodies the values, beliefs, and emotions of the people, serving as a means of communication and storytelling. For instance, the haunting melodies of Celtic folk music recount tales of ancientheroes and mythical creatures, while the rhythmic beats of African drumming convey messages of unity and celebration within tribal communities.One of the distinguishing features of traditional music is its authenticity and simplicity. Unlike modern commercialized music, which often relies on complex production techniques and technology, traditional music relies on raw talent and craftsmanship. Instruments such as the violin, flute, tabla, or guzheng are commonly used, each producing unique sounds that resonate with thecultural identity of the music. Moreover, traditional music often incorporates elements of improvisation, allowing musicians to express themselves freely and create spontaneous moments of beauty and emotion.Another aspect of traditional music appreciation is understanding the role it plays in society. Traditional music is more than just entertainment; it serves as a unifying force that brings people together and strengthens social bonds. In many cultures, music accompanies significant life events such as weddings, funerals, andreligious ceremonies, imparting meaning and significance to these occasions. Moreover, traditional music fosters a sense of belonging and pride among community members, preserving cultural heritage and identity in an ever-changing world.In addition to its cultural significance, traditional music offers numerous benefits to individuals' well-being and mental health. Studies have shown that listening to traditional music can reduce stress, anxiety, and depression, promoting relaxation and emotional healing. Moreover, actively participating in traditional music-making, whether through singing, dancing, or playing instruments, enhances cognitive function, memory retention, and social skills. By engaging with traditional music, individuals can connect with their roots, gain a deeper understanding of their cultural heritage, and develop a greater appreciation for diversity and inclusivity.Furthermore, traditional music appreciation fosters cross-cultural understanding and appreciation. In an increasingly globalized world, where cultures are becomingmore interconnected, traditional music serves as a bridge that transcends language barriers and fosters mutualrespect and understanding. Through music festivals, workshops, and cultural exchanges, people from different backgrounds can come together to celebrate their shared humanity and learn from one another's traditions. In this way, traditional music becomes a powerful tool forpromoting peace, harmony, and cooperation on a global scale.In conclusion, traditional music appreciation is not merely an academic pursuit but a journey of discovery and enlightenment. By immersing oneself in the rich tapestry of traditional music from around the world, one can gaininsight into the collective human experience and appreciate the beauty of cultural diversity. Whether through listening, performing, or studying, traditional music offers endless opportunities for exploration and enrichment, enriching our lives and enriching our understanding of the world we inhabit. As we continue to navigate the complexities of the modern world, let us not forget the timeless wisdom and beauty of traditional music, which has the power to uplift, inspire, and unite us all.。

关于百家姓中蔡姓的作文素材

关于百家姓中蔡姓的作文素材

关于百家姓中蔡姓的作文素材示例回答如下1:In the book "Bai Jia Xin" (百家姓), the surname Cai (蔡) holds a significant position. The Cai surname is one of the most common surnames in China, with a long history and rich cultural heritage.The origin of the Cai surname can be traced back to ancient times. According to historical records, during the Zhou Dynasty, there was a state called Cai (蔡国), which was located in present-day Henan Province. The descendants of the rulers of this state adopted "Cai" as their surname to honor their ancestors.Throughout history, the Cai surname has produced many prominent figures in various fields. One of the most famous is Cai Lun (蔡伦), who is credited with inventing paper during the Eastern Han Dynasty. His invention revolutionized the way information was recorded and transmitted, and it had a profound impact on the development of civilization.In addition to Cai Lun, there have been numerous otherinfluential individuals with the Cai surname. Cai Wenji (蔡文姬), also known as Cai Yan, was a talented poet and musician during the Three Kingdoms period. Her literary works are still admired today for their beauty and depth.Furthermore, the Cai surname is not limited to China. It has spread to other parts of the world through migration and cultural exchange. Many overseas Chinese with the surname Cai have made significant contributions in their adopted countries, especially in the fields of business, academia, and politics.The Cai surname also carries symbolic meanings in Chinese culture. The character "蔡" consists of two parts: "艹" (cao), which represents plants or vegetation, and "才" (cai), which means talent or ability. Therefore, the surname Cai is often associated with qualities such as intelligence, creativity, and success.In conclusion, the Cai surname in the "Bai Jia Xin" holds a special place in Chinese history and culture. It represents a long lineage of accomplished individuals who have left their mark on various fields. The Cai surname's significance goesbeyond borders, as it has spread to different parts of the world. Its rich history and symbolic meanings make it a fascinating subject for further exploration and study.在《百家姓》这本书中,蔡姓在其中占据了重要的位置。

化学耕作还是有机耕作英语作文

化学耕作还是有机耕作英语作文

化学耕作还是有机耕作英语作文英文回答:Chemical farming and organic farming are two distinct approaches to agricultural cultivation, each with its own advantages and disadvantages. Chemical farming, also known as conventional farming, relies on synthetic fertilizers, pesticides, and herbicides to improve crop yields and protect plants from pests and diseases. Organic farming, on the other hand, eschews synthetic inputs in favor of natural methods, such as crop rotation, composting, and biological pest control.Chemical farming.Pros:Increased crop yields: Synthetic fertilizers provide essential nutrients that plants need to grow, leading to higher productivity.Pest and disease control: Pesticides and herbicides effectively target harmful organisms, reducing crop damage and improving quality.Time-saving: Chemical inputs can simplify farming practices, reducing the labor and time required for cultivation.Cons:Environmental pollution: Synthetic fertilizers and pesticides can leach into soil and water, contaminating ecosystems and harming wildlife.Health concerns: Residues of pesticides and herbicides on food products can pose potential health risks to consumers.Soil degradation: Overuse of synthetic chemicals can deplete soil fertility and disrupt natural nutrient cycles.Organic farming.Pros:Reduced environmental impact: Organic farming minimizes pollution and protects biodiversity by avoiding synthetic inputs.Enhanced soil health: Natural methods, such as crop rotation and composting, improve soil structure and fertility, promoting plant health.Improved food quality: Organic produce is often perceived as being more nutritious and flavorful due to the absence of chemical treatments.Cons:Lower crop yields: Organic farming practices may result in lower yields compared to chemical farming, especially in the short term.Increased labor costs: Organic farming requires more labor-intensive methods, such as manual weeding and pest monitoring.Pest and disease susceptibility: Organic crops may be more vulnerable to pests and diseases without the use of synthetic pesticides or herbicides.The choice between chemical and organic farming depends on several factors, including the specific crop, soil conditions, and societal values. Both approaches have their merits, and farmers must carefully weigh the potential benefits and risks before making a decision.中文回答:化学耕作。

文物渴望归家作文英文

文物渴望归家作文英文

文物渴望归家作文英文The desire for cultural relics to return home is a sentiment that speaks to the deep connection between a country and its heritage. 文物渴望回家的渴望彰显了一个国家与其遗产之间深厚的联系。

The significance of these artifacts to a nation's identity and history cannot be overstated. 这些文物对一个国家的身份和历史的意义不可高估。

When cultural relics are displaced or taken away from their place of origin, a sense of loss and longing permeates through the fabric of society. 当文物被转移或带离它们的原产地时,一种失落和渴望的感觉渗透到社会的结构之中。

It is the duty of every individual to advocate forthe return of these treasures to their rightful home. 每个人都有责任倡导这些珍宝回到它们应在的家园。

The repatriation of cultural relics is not only a legal and ethical issue, but also a moral imperative. 文物的归还不仅仅是一个法律和道德问题,更是一种道义责任。

These artifacts are not commodities to be bought, sold, or traded at the whims of collectors or institutions. 这些文物不是应该让收藏家或机构任意买卖或交易的商品。

云南文化多样性的英文作文

云南文化多样性的英文作文

云南文化多样性的英文作文From the perspective of ethnic origin and language family. The ethnic minorities in Yunnan mainly developed from the diqiang, Pu and Baiyue ethnic groups that lived in the pre-Qin period after two or three thousand years of ethnic integration and ethnic differentiation. The Di-Qiang groups gradually formed the Bai, Yi, Hani, Lahu and Achang groups in Tibetan and Burmese languages; the Baiyue groups gradually formed the Zhuang and Dai and Shui groups; and the Pu gradually formed the Brown, Deang and Wa groups in Meng-Khmer languages. In addition, there were also the Tibetan, Miao, Yao, Buyi, Mongolian, Hui and Pumi people who gradually moved to Yunnan from the Tang, Song Dynasties to the Yuan, Ming and Qing Dynasties. Up to now, Yunnan is a province with the largest number of ethnic groups living in the world. Due to the different ethnic sources and the different historical changes, each ethnic group has deposited and carried different cultures into Yunnan, making the Yunnan ethnic culture show the characteristics ofmulti-source. These different languages, diet, architecture, clothing, culture and art, festivals, life etiquette and other cultural landscapes, which laid the foundation of Yunnan ethnic and cultural diversity. At the same time, our variousnationalities in the constant communication and integration, form weal, sharing weal and woe, life and death, destiny community, "I, I have you", close, to create a colorful, magical and gorgeous Chinese nation culture, in China and the world to form a unique diversity of cultural landscape. Yunnan is not only a treasure land of biodiversity enrichment in China, but also one of the model areas where biodiversity and cultural diversity complement each other.From yak grazing to paddy field farming, diversified production and life style.Yunnan special geographical location and complex natural conditions, for the origin, evolution and reproduction of various organisms provides the suitable environment, with complex and diverse ecosystem, species resources and genetic resources, biodiversity in the first of the country, is 17 key biodiversity areas in China and one of the richest 34 species hotspots, known as the "animal and plant kingdom" "species gene pool", "herbs" "spices" reputation. Such an ecological basis encourages all ethnic groups to accumulate and form their own distinctive ways of production and life in the long period of time due to their different environments.。

微生物名词解释

微生物名词解释

GlossaryActinomycetes(放线菌,放线菌属)A group of filamentous, funguslike bacteria.active transport (主动运输)Nutrient transport method that requires carrier proteins in the membranes of the living cells and the expenditure of energy.adenovirus Noenveloped DNA virus; means of transmission is human-to-human via respiratory and ocular secretions.aerobe(需氧微生物)A microorganism that lives and grows in the presence of free gaseous oxygen (O2).aerobic respiration(需氧呼吸)Respiration in which the final electron acceptor in the electron transport chain is oxygen (O2).agar(琼脂)A polysaccharide found in seaweed and commonly used to prepare solid culture media.AIDS(艾滋病)Acquired immunodeficiency syndrome. The complex of signs and symptoms characteristic of the late phase of human immunodeficiency virus (HIV) infection.algae(藻类)Photosynthetic, plant-like organisms which generally lack the complex structure of plants; they may be single-celled or multicellular, and inhabit diverse habitats such as marine and freshwater environments, glaciers, and hot springs.Ames test(艾姆斯氏试验)A method for detecting mutagenic and potentially carcinogenic agents based upon the genetic alteration of nutritionally defective bacteria.ammonification(氨化作用)Phase of the nitrogen cycle in which ammonia is released from decomposing organic material.anaerobe(厌氧性微生物,厌氧菌)A microorganism that grows best, or exclusively, in the absence of oxygen.anaerobic respiration(无氧呼吸)Respiration in which the final electron acceptor in the electron transport chain is an inorganic molecule containing sulfate, nitrate, nitrite, carbonate, etc. antagonism(拮抗作用)Relationship in which microorganisms compete for survival in a common environment by taking actions that inhibit or destroy another organism.antibiotic(抗生素)A chemical substance from one microorganism that can inhibit or kill another microbe even in minute amounts.archaea(古生菌)Prokaryotic single-celled organisms of primitive origin that have unusual anatomy, physiology and genetics, and live in harsh habitats; when capitalized (Archaea) the term refers to one of the three domains of living organisms as proposed by Woese. arthrospore(分节孢子)A fungal spore formed by the septation and fragmentation of hyphae. ascospore (囊孢子,子囊孢子)A spore formed within a saclike cell (ascus) of Ascomycota following nuclear fusion and meiosis.ascus(子囊)Special fungal sac in which haploid spores are created.autoclave(高压锅)A sterilization chamber which allows the use of steam under pressure to sterilize materials. The most common temperature/pressure combination for an autoclave is 121℃and 15 psi.autotroph(自养生物)A microorganism that requires only inorganic nutrients and whose sole source of carbon is carbon dioxide.Bacillus(芽孢杆菌)Bacterial cell shape that is cylindrical (longer than it is wide).back-mutation(回复突变)A mutation which counteracts an earlier mutation, resulting in therestoration of the original DNA sequence.bacteria (细菌)Category of prokaryotes with peptidoglycan in their cell wails and a single, circular chromosome. This group of small cells is widely distributed in the earth’s habitats. Bacteria (plural of bacterium) When capitalized can refer to one of the three domains of living organisms proposed by Woese, containing all non- archaea prokaryotes.bacterial chromosome 细菌染色体A circular body in bacteria that contains the primary genetic material. Also called nucleoid.Bacteriophage噬菌体A virus that specifically infects bacteria.bacterium 杆菌属A tiny unicellular prokaryotic organism that usually reproduces by binary fission and usually has a peptidoglycan cell wall, has various shapes, and can be found in virtually any environment.basidiospore(芽孢)A sexual spore that arises from a basidium. Found in basidiomycota fungi. Bdellovibrio(蛭弧菌属)A bacterium that preys on certain other bacteria. It bores a hole into a specific host and inserts itself between the protoplast and the cell wall. There it elongates before subdividing into several cells and devouring the host cell.capsule蒴果In bacteria, the loose, gel-like covering or slime made chiefly of simple polysaccharides. This layer is protective and can be associated with virulence. Chemoautotroph华能自养生物An organism that relies upon inorganic chemicals for its energy and carbon dioxide for its carbon. Also called a chemolithotroph.chemoheterotroph华能异养生物Microorganisms that derive their nutritional needs from organic compounds.chemotaxis趋化性The tendency of organisms to move in response to a chemical gradient (toward an attractant or to avoid adverse stimuli).chitin 几丁质A polysaccharide similar to cellulose in chemical structure. This polymer makes up the horny substance of the exoskeletons of arthropods and certain fungi.chromosome染色体The tightly coiled bodies in cells that are the primary sites of genes.Clone无性繁殖A colony of cells (or group of organisms) derived from a single cell (or single organism) by asexual reproduction. All units share identical characteristics. Also used as a verb to refer to the process of producing a genetically identical population of cells or genes. colony菌落A macroscopic cluster of cells appearing on a solid medium, each arising from the multiplication of a single cell.commensalism共栖An unequal relationship in which one species derives benefit without harming the other.conjugation结合作用In bacteria, the contact between donor and recipient cells associated with the transfer of genetic material such as plasmids. Can involve special (sex) pili. Also a form of sexual recombination in ciliated protozoans.death phase死亡期End of the cell growth due to lack of nutrition, depletion of environment, and accumulation of wastes. Population of cells begins to die.decomposition分解The breakdown of dead matter and wastes into simple compounds, that can be directed back into the natural cycle of living things.diffusion扩散The dispersal of molecules, ions, or microscopic particles propelled down a concentration gradient by spontaneous random motion to achieve a uniform distribution. diploid 二倍体Somatic cells having twice the basic chromosome number. One set in the pair is derived from the father, and the other from the mother.direct, or total cell count 细胞计数1. Counting total numbers of individual cells being viewed with magnification. 2. Counting isolated colonies of organisms growing on a plate of mediaas a way to determine population size.endospore内生孢子A small, dormant, resistant derivative of a bacterial cell that germinates under favorable growth conditions into a vegetative cell. The bacterial genera Bacillus and Clostridium are typical sporeformers.eubacteria 真细菌Term used for non-archaea prokaryotes, stands for "true bacteria" eukaryotic cell真核细胞A cell that differs from a prokaryotic cell chiefly by having a nuclear membrane (a well-defined nucleus), membrane-bounded subcellular organelles, and mitotic cell division.Eukarya真核生物One of the three domains (sometimes called superkingdoms) of living organisms, as proposed by Woese; contains all eukaryotic organisms.eutrophication富营养化The process whereby dissolved nutrients resulting from natural seasonal enrichment or industrial pollution of water cause overgrowth of algae and cyanobacteria to the detriment of fishand other large aquatic inhabitants.fermentation 发酵The extraction of energy through anaerobic degradation of substrates into simpler, reduced metabolites. In large industrial processes, fermentation can mean any use of microbial metabolism to manufacture organic chemicals or other products.fimbria 菌毛A short, numerous surface appendage on some bacteria that provides adhesion but not locomotion.flagellum鞭毛A structure that is used to propel the organism through a fluid environment. gene基因A site on a chromosome that provides information for a certain cell function. A specific segment of DNA that contains the necessary code to make a protein or RNA molecule. generation time代时Time required for a complete fission cycle-from parent cell to two new daughter cells. Also called doubling time.genome 基因组染色体组The complete set of chromosomes and genes in an organism. Genotype 基因型The genetic makeup of an organism. The genotype is ultimately responsible for an organism's phenotype, or expressed characteristics.Gram stain革兰氏染色剂A differential stain for bacteria useful in identification and taxonomy.Gram-positive organisms appear purple from crystal violet- mordant retention, whereas gram-negative organisms appear red after loss of crystal violet and absorbance of the safranin counterstain.growth curve生长曲线A graphical representation of the change in population size over time.This graph has four periods known as lag phase, exponential or log phase, stationary phase, and death phase.growth factor生长因子An organic compound such as a vitamin or amino acid that must be provided in the diet to facilitate growth. An essential nutrient.halophile好盐菌 A microbe whose growth is either stimulated by salt or requires a high concentration of salt for growth.haploid 单倍体Having a single set of unpaired chromosomes, such as occurs in gametes and certain microbes.host 宿主Organism in which smaller organisms or viruses live, feed, and reproduce.human immunodeficiency virus (HIV)艾滋病病毒 A retro virus that causes acquired immunodeficiency syndrome (AIDS).intron 内含子The segments on split genes of eucaryotes that do not code for polypeptide. They can have regulatory functions. See exon.in vitro离体Literally means "in glass," signifying a process or reaction occurring in an artificial environment, as in a test tube or culture medium.in vivo生物体内Literally means “in a living being,” signifying a process or react ion occurring ina living thing.Koch’s postulates科赫法则A procedure to establish the specific cause of disease. In all cases of infection: ( 1 ) The agent must be found; (2) inoculations of a pure culture must reproduce the same disease in animals; (3) the agent must again be present in the experimental animal: and (4) a pure culture must again be obtained.lag phase延迟期The early phase of population growth during which no signs of growth occur.L form 缺壁细菌L-phase variants; wall-less forms of some bacteria that are induced by drugs or chemicals. These forms can be involved in infections.lipopolysaceharide 脂多糖 A molecular complex of lipid and carbohydrate found in the bacterial cell wall. The lipopolysaccharide (LPS) of gram-negative bacteria is an endotoxin with generalized pathologic effects such as fever.log phase指数期Maximum rate of cell division during which growth is geometric in its rate of increase. Also called exponential growth phase.Meiosis 减数分裂The type of cell division necessary for producing gametes in diploid organisms. Two nuclear divisions in rapid succession produce four gametocytes, each containing a haploid number of chromosomes.minimum inhibitory concentration (MIC) 最低抑菌浓度The smallest concentration of drug needed to visibly control microbial growth.minimum temperature 最低温度The lowest temperature at which an organism will grow. missense mutation错义突变A mutation in which a change in the DNA sequence results in a different amino acid being incorporated into a protein, with varying results.mitosis 有丝分裂Somatic cell division that preserves the somatic chromosome number. mycelium 菌丝菌丝体The filamentous mass that makes up a mold. Composed of hyphae. Mycorrhizae 菌根Various species of fungi adapted in an intimate, mutualistic relationship to plant roots.nitrification硝化作用Phase of the nitrogen cycle in which ammonium is oxidized.nitrogen fixation固氮作用A process occurring in certain bacteria in which atmospheric N2 gas is converted to a form (NH4) usable by plants.nonsense mutation 无义突变A mutation that changes an amino acid-producing codon into a stop codon, leading to premature termination of a protein.nucleus 细胞核The central core of an atom, composed of protons and neutrons.obligate专性Without alternative; restricted to a particular characteristic. Example: An obligate parasite survives and grows only in a host; an obligate aerobe must have oxygen to grow; an obligate anaerobe is destroyed by oxygen.optimum temperature最适温度The temperature at which a species shows the most rapid growth rate.parasite 寄生虫An organism that lives on or within another organism (the host), from which it obtains nutrients and enjoys protection. The parasite produces some degree of harm in the host.passive transport 被动运输Nutrient transport method that follows basic physical laws and does not require direct energy input from the cell.pasteurization 巴斯消毒法Heat treatment of perishable fluids such as milk, fruit juices, or wine to destroy heat-sensitive vegetative cells, followed by rapid chilling to inhibit growth of survivors and germination of spores. It prevents infection and spoilage.pathogen 病原体Any agent, usually a virus, bacterium, fungus, protozoan, or helminth, thatcauses disease.phage 噬菌体A bacteriophage; a virus that specifically parasitizes bacteria.phenotype表型The observable characteristics of an organism produced by the interaction between its genetic potential (genotype) and the environment.photoautotroph 光合自养生物An organism that utilizes light for its energy and carbon dioxide chiefly for its carbon needs.pill Small, stiff filamentous appendages in gram-negative bacteria that function in DNA exchange during bacterial conjugation.plasmids质粒Extrachromosomal genetic units characterized by several features. A plasmid is a double-stranded DNA that is smaller than and replicates independently of the cell chromosome; it bears genes that are not essential for cell growth; it can bear genes that code for adaptive traits; and it is transmissible to other bacteria.polysaccharide多糖A carbohydrate that can be hydrolyzed into a number of monosaccharides.Examples: cellulose, starch, glycogen.prion朊病毒A concocted word to denote “proteinaceous infectious agent”; a cytopathic protein associated with the slow-virus spongiform encephalopathies of humans and animals. prophage 原噬菌体A lysogenized bacteriophage; a phage that is latently incorporated into the host chromosome instead of undergoing viral replication and lysis.protoplast原生质体A bacterial cell whose cell wall is completely lacking and that is vulnerable to osmotic lysis.protozoa 原生动物A group of single-celIed, eucaryotic organisms.pseudohypha 假菌丝 A chain of easily separated, spherical to sausage-shaped yeast cells partitioned by constrictions rather than by septa.pure culture 纯培养A container growing a single species of microbe whose identity is known. Retrovirus逆转录酶病毒A group of RNA viruses (including HIV) that have the mechanisms for converting their genorne into a double strand of DNA t hat can be inserted on a host’s chromosome.reverse transcriptase逆转录酶The enzyme possessed by retrovimses that carries out the reversion of RNA to DNA a form of reverse transcription.rhizobia 根瘤菌Bacteria that live in plant roots and supply supplemental nitrogen that boosts plant growth.rhizosphere 根际The zone of soil, complete with microbial inhabitants, in the immediate vicinity of plant roots.rickettsias 立克次体Medically important family of bacteria, commonly carried by ticks, lice, and fleas. Significant cause of important emerging diseases.root nodules 根瘤Small growths on the roots of legume plants that arise from a symbiotic association between the plant tissues and bacteria (Rhizobia). This association allows fixation of nitrogen gas from the air into a usable nitrogen source for the plant.silent mutation同义突变A mutation that, because of tire degeneracy of the genetic code, results in a nucleotide change in both the DNA and mRNA but not the resultant amino acid and thus, not the protein.spore孢子A differentiated, specialized cell form that can be used for dissemination, for adverse conditions, and/or for reproduction.Spores are usually unicellular and may develop into gametes or vegetative organisms.stationary growth phase 稳定期Survival mode in which cells either stop growing or grow very slowly.sterilization 灭菌Any process that completely removes or destroys all viable microorganisms, including viruses, from an object or habitat. Material so treated is sterile.strict, or obligate anaerobe严格厌氧微生物An organism which does not use oxygen gas in metabolism and cannot survive in oxygen’s presence.symbiosis共生An intimate association between individuals from two species; used as a synonym for mutualism.synergism协同作用The coordinated or correlated action by two or more drugs or microbes that results in a heightened response or greater activity.temperate phage 温和噬菌体A bacteriophage that enters into a less virulent state by becoming incorporated into the host genome as a prophage instead of in the vegetative or lytic form that eventually destroys the cell.template 模板The strand in a double stranded DNA molecule which is used as a model to synthesize a complementary strand of DNA or RNA during replication or transcription. thermal death point致死温度The lowest temperature that achieves sterilization in a given quantity of broth culture upon a 10-minute exposure. Examples: 55℃for Escherichia coli, 60℃for Mycobacterium tuberculosis, and 120℃for spores.thermal death time热致死时间The least time required to kill all cells of a culture at a specified temperature.thermophile 嗜热生物A microorganism that thrives at a temperature of 50℃or higher. transcription转录mRNA synthesis; the process by which a strand of RNA is produced against a DNA template.transduction转导The transfer of genetic material from one bacterium to another by means of a bacteriophage vector.transformation转化In microbial genetics, the transfer of genetic material contained in “naked”DNA fragments from a donor cell to a competent recipient cell.transposon转位子A DNA segment with an insertion sequence at each end, enabling it to migrate to another plasmid, to the bacterial chromosome, or to a bacteriophage.Vibrio弧菌A curved, rod-shaped bacterial cell.virulence 毒性In infection, the relative capacity of a pathogen to invade and harm host cells. zygospore 接合孢子A thick-walled sexual spore produced by the zygomycete fungi. It develops from the union of two hyphae, each bearing nuclei of opposite mating types.。

Immigrants Contributing to Society

Immigrants Contributing to Society

Immigrants Contributing to Society Immigrants have always been an essential part of society, contributing to the cultural, economic, and social fabric of their new homes. From the earliest waves of migration to the present day, immigrants have brought their skills, knowledge, and unique perspectives to enrich the countries they settle in. While some may argue that immigrants are a burden on society, the reality is that they play a crucial role in driving innovation, filling labor shortages, and revitalizing communities. One of the most significant contributions that immigrants make to society is through their labor force participation. Immigrants often take on jobs that native-born workers are unwilling to do, such as agricultural work, construction, and caregiving. In doing so, they help fill critical labor shortages and keep essential industries running. Without immigrant workers, many sectors of the economy would struggle to find the manpower they need to function effectively. This, in turn, would have a negative impact on the overall economic health of the country. Moreover, immigrants are also significant contributors to entrepreneurship and innovation. Many immigrants come to their new countries with a strong entrepreneurial spirit, starting their own businesses and creating jobs for both immigrants and native-born citizens. In fact, immigrants are more likely to start businesses than native-born individuals, and these businesses often bring new ideas, products, and services to the market. This not only stimulates economic growth but also fosters a culture of innovation and diversity that benefits society as a whole. Furthermore, immigrants bring a rich diversity of cultures, traditions, and perspectives to their new communities. This diversity adds vibrancy and vitality to society, enriching the cultural landscape and broadening the horizons of the people they encounter. Immigrants often introduce new foods, music, art, and traditions that enhance the cultural tapestry of their adopted country. This cross-pollination of ideas and customs fosters greater understanding and appreciation among different groups, ultimately strengthening social cohesion and harmony. In addition to their economic and cultural contributions, immigrants also play a vital role in addressing demographic challenges. Many developed countries are facing aging populations and declining birth rates, leading to concerns about the sustainability of social welfare systems and the futureworkforce. Immigration helps to mitigate these demographic challenges by bringingin younger, working-age individuals who can support the aging population and contribute to the tax base. Without immigration, many countries would struggle to maintain the levels of economic growth and social stability necessary for a high quality of life for their citizens. Despite these significant contributions, immigrants often face numerous challenges and barriers as they seek to integrate into their new societies. Language barriers, cultural differences, and discrimination can make it difficult for immigrants to fully participate and contribute. This can lead to feelings of isolation, exclusion, and frustration, hindering their ability to realize their full potential and make the most significant possible impact on their new communities. As a society, it isessential to recognize and address these challenges, ensuring that immigrants are given the support and opportunities they need to thrive and contribute fully. In conclusion, immigrants are an indispensable part of society, bringing a wealth of skills, talents, and perspectives that enrich and strengthen their new communities. From their contributions to the labor force and entrepreneurship to their cultural enrichment and role in addressing demographic challenges, immigrants play a vital role in driving progress and prosperity. As a society, it is crucial to recognize and appreciate the valuable contributions of immigrants, while also working to address the barriers and challenges they face in their integration. By doing so, we can build more inclusive, dynamic, and resilient communities that benefit all members, regardless of their background or origin.。

英语作文英语的由来

英语作文英语的由来

英语作文英语的由来Title: The Origin of the English Language。

English, as we know it today, has a rich and intricate history that spans over centuries. Its evolution is a fascinating journey, shaped by diverse influences from various cultures and historical events. In this essay, we will delve into the origins of the English language,tracing its development from its earliest roots to its global prominence in the modern world.The story of English begins over a millennium ago, with the arrival of Germanic tribes to the British Isles in the early Middle Ages. These tribes, including the Angles, Saxons, and Jutes, brought with them their own dialects, which laid the foundation for Old English. 。

Old English, spoken from around the 5th to the 11th century, was heavily influenced by the languages of the indigenous Celtic peoples already inhabiting the BritishIsles. Additionally, Norse invaders, particularly the Vikings, left their mark on the language through trade, conquest, and settlement, introducing words and grammatical structures that enriched the linguistic landscape.The Norman Conquest of 1066 was a pivotal moment in the history of English. Following William the Conqueror's victory at the Battle of Hastings, French became the language of the ruling elite in England. This led to a significant influx of French vocabulary into English, particularly in areas related to government, law, and culture. The resulting blend of Anglo-Saxon and Norman French, known as Middle English, marked a period of linguistic transition and innovation.Middle English literature flourished during the High Middle Ages, producing timeless works such as Geoffrey Chaucer's "Canterbury Tales" and Sir Thomas Malory's "Le Morte d'Arthur." These literary masterpieces not only reflected the linguistic diversity of the time but also contributed to the standardization and enrichment of the English language.The invention of the printing press by Johannes Gutenberg in the 15th century revolutionized communicationin Europe and facilitated the spread of the English language. The publication of influential texts such as the King James Bible and William Shakespeare's plays helped to establish English as a dominant literary and cultural force.The Age of Exploration and Colonialism further expanded the influence of English across the globe. British colonization led to the spread of English to North America, the Caribbean, Africa, Asia, and the Pacific, where it coexisted and intermingled with indigenous languages, creoles, and pidgins. This global diffusion laid the groundwork for the emergence of Modern English as a truly international language.In the modern era, English has become the lingua franca of the global community, serving as the primary means of communication in fields such as science, technology, business, and diplomacy. The rise of the internet anddigital media has further accelerated the spread of English,breaking down linguistic barriers and connecting people from diverse cultural backgrounds.Today, English continues to evolve and adapt, absorbing new words, expressions, and influences from around the world. Its resilience and versatility are testament to its status as a living, breathing language, constantly shaped by the dynamic forces of history, society, and culture.In conclusion, the English language has a complex and multifaceted origin, shaped by a myriad of historical, cultural, and linguistic factors. From its humble beginnings as a Germanic dialect spoken by Anglo-Saxon tribes to its current status as a global language of communication and commerce, English has undergone a remarkable journey of transformation and expansion. As we look to the future, the story of English remains an enduring testament to the power of language to unite, inspire, and transcend boundaries.。

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a r X i v :a s t r o -p h /9704148v 1 15 A p r 1997Chemical Enrichment and the Origin of theColour-Magnitude Relation of Elliptical Galaxies in aHierarchical Merger ModelGuinevere Kauffmann 1&St´e phane Charlot 21Max-Planck Institut f¨u r Astrophysik,D-85740Garching,Germany 2Institut d’Astrophysique du CNRS,98bis Boulevard Arago,Paris,France Abstract In this paper,we present a model of the formation and chemical enrichment of elliptical galaxies that differs from the conventional picture in two fundamental ways:1.Ellipticals do not form in a single monolithic collapse and burst of star formation at high redshift.Instead,most of their stars form at modest rates in disk galaxies,which then merge to form the ellipticals.2.Galaxies do not undergo “closed-box”chemical evolution.Instead,metals can be transferred between the stars,cold gas and the hot gas halos of the galaxies.It is assumed that metals are ejected out of disk galaxies during supernova explosions and these metals enter the hot gas component.The fact that metals are more easily ejected from small galaxies leads to the establishment of a mass-metallicity relation for the disk systems.Big ellipticals are more metal rich because they are formed from the mergers of bigger disks.We use semi-analytic techniques to follow the formation,evolution,and chemical enrich-ment of cluster elliptical galaxies in a merging hierarchy of dark matter halos.The in-clusion of the new metallicity-dependent spectral synthesis models of Bruzual &Charlotenable us to compute the colours,line indices and mass-to-light ratios of these galaxies.We find that with physically realistic parameters and with the assumption that feedback is efficient,even in massive galaxies,we are able to reproduce the slope and scatter of the colour-magnitude and the Mg 2−σrelations.We are not able to match the increase in M/L for bright ellipticals if we assume their mass to measure purely the total quantity of stars in the galaxy.We also study the evolution of these relations to high redshift.We show that the luminosity-metallicity relation does not change with redshift,but the mean stellar age of the galaxies scales with the age of the Universe.This is why the evolution of cluster ellipticals appears to be well described by simple passive evolution.Finally,we study the enrichment history of the intracluster gas.Our models predict that more than 80%of the metals were ejected by galaxies with circular velocities less than 250km s −1at redshifts greater than 1.The metallicity of the ICM is thus predicted to evolve very little out to z >1.Keywords:galaxies:formation,evolution;galaxies:elliptical and lenticular;galaxies:stellar content1IntroductionThe relationship between the colours,line strengths and luminosities of elliptical galaxies is potentially a source of information about physical processes important during their formation. The conventional interpretation of the colour-magnitude relation of ellipticals is that it is primarily a metallicity effect(Faber1977;Dressler1984;Vader1986).It is often assumed that elliptical galaxies form monolithically in a single giant burst of star formation at high redshift.Supernova explosions heat the gas,and when its thermal energy exceeds its binding energy,a galactic wind is produced,which is assumed to interrupt further star formation and enrichment.Since the binding energy per unit mass of gas is higher in more massive galaxies,these are able to retain their gas for much longer times and so to reach higher metallicities than less massive galaxies(Larson1974;Matteuci&Tornamb´e1987;Arimoto& Yoshii1987;Bressan et al1996).This interpretation is not unique,however,because colours and line strengths are degenerate in age and metallicity.As a result,the colour-magnitude relation of local ellipticals can also be interpreted as an increase in mean stellar age with luminosity(Worthey1996).In recent work,Kodama&Arimoto(1997)have pointed out that the evolution of the colour-magnitude relation to high redshift does not support the hypothesis that age effects alone are responsible for the redder colours of the brighter ellipticals.Following this,Charlot,Ferreras&Silk(1997,in preparation)have explored models where both age and metallicity are important,and have shown that several of these can provide equally good fits to the data.An alternative approach to interpreting the spectra of ellipticals is to begin with a more realistic dynamical picture for the formation of these objects,and then to study the properties of their stellar populations by applying spectral synthesis techniques.Recently,there has been considerable progress in modelling the observed properties of ellipticals in a scenario where they are formed by the merging of disk galaxies in a universe where structure is built through hierarchical clustering(Kauffmann1996b,Baugh,Cole&Frenk1996).This work has,for the first time,placed the theory of the formation and evolution of elliptical galaxies in a proper cosmological context.In these models,star formation takes place mainly in centrifugally-supported disks,formed when gas cools and condenses at the centres of virialized halos of dark matter.A self-regulated balance between cooling and feedback from supernova explosions maintains star formation at a roughly constant rate in these disks.If two disk galaxies merge once their surrounding halos have coalesced,an elliptical galaxy is formed and all cold gas present in the merger remnant is transformed instantaneously into stars in a“burst”. Kauffmann(1996b)showed that although ellipticals are predicted to have been assembled by relatively recent mergers(z<1)in a standard cold dark matter(CDM)cosmology,most of their stars form at considerably higher redshift in their disk-galaxy progenitors.The V-band luminosity-weighted stellar age of cluster ellipticals was shown to vary between8and12Gyears and the scatter in the predicted V−K and U−V colours was of order0.04,consistent with the small observed scatter of Virgo and Coma cluster elliptical colours(Bower,Lucey&Ellis1992). The model presented in that paper did not include any scheme for the chemical enrichment of galaxies and it was unable to reproduce the slope of the observed colour-magnitude relation. An important conclusion of this work was that age effects in hierarchical models could not alone account for the redder colours of the more massive ellipticals.We have now included a simple prescription for chemical evolution in our semi-analyticgalaxy formation scheme in order to analyze the effect of variations in metallicity on the observed properties of ellipticals.Supernovae take place in stars forming disk galaxies and the explosions cause cold gas and metals to be ejected into the halo,where the metals are mixed with the hot halo gas.The efficiency with which this process occurs depends on the potential well depth,so that less massive galaxies eject more material and hence produce fewer stars and metals per unit mass of available cold gas.The metallicity of disk galaxies thus increases as a function of their mass.We then show that in a hierarchical merger picture, bright ellipticals form from mergers of substantially more massive disks than faint ellipticals. This lays the theoretical groundwork for understanding the origin of a mass-metallicity relation for elliptical galaxies.We then compare the predictions of the model with observational data.To do this,we make use of the new stellar population synthesis models of Bruzual&Charlot(1997,in preparation);these enable us to compute the colours and spectral line indices of evolving stellar populations of different metallicities.We show that with physically reasonable choices for the free parameters in our model,we are able to reproduce both the slope and the scatter of the U−V and V−K colour-magnitude relations of cluster ellipticals.In addition,we obtain a goodfit to the slope of observed relation between the Mg2index and the stellar velocity dispersionσ,where it is assumed thatσsimply scales in proportion to the circular velocity of the halo in which the elliptical galaxy formed.We also examine the evolution of these relations to high redshift and show that out to a redshift of1in a standard CDM cosmology, the slopes change very little and the colours and index values atfixed luminosity shift to lower values as expected for a passively evolving population of stars.At redshifts greater than one, there is a slightflattening in the slopes of the relations,caused by the slightly younger mean ages of the bright ellipticals relative to the faint ones.Although the colour-magnitude relations are reproduced very well by our model,we can-not account for the observed increase in the mass-to-light ratios of bright elliptical galaxies if we assume the mass,estimated using the central line-of-sight velocity dispersionσ,is purely a measure of the total quantity of stars in the galaxy.We hypothesize that since massive ellipticals are built up through a greater number of mergers than their less massive counter-parts,more dark matter may end up being mixed with their stars.Finally,since our chemical evolution model tracks the recycling of heavy elements between stars,cold gas,and the hot intergalactic medium,we are able to study the enrichment history of the hot gas in clusters. With a Sn Ia+Sn II yield of twice solar,we are able to reproduce the observed ratio of iron mass to total blue luminosity in nearby clusters(Renzini et al1993).We show that80%of the metals are produced at redshifts greater than1in galaxies with circular velocities less than 250km s−1.The metallicity of rich clusters is predicted to evolve very little out to redshifts of1and beyond.2Modelling the Formation and Chemical Enrichment of Elliptical Galaxies2.1Semi-analytic models of elliptical galaxy formation in a hierar-chical UniverseThe semi-analytic model we employ is the same as that used by Kauffmann(1996b)to compute the stellar ages of elliptical galaxies and bulges formed by mergers in a cold dark matter universe.The reader is referred to that paper for more background.The new material in the present paper is a prescription for chemical enrichment and the transfer of metals between stars,cold galactic gas and hot halo gas.We describe this in detail in the next section. More details about semi-analytic techniques may be found in Kauffmann&White(1993), Kauffmann,White&Guiderdoni(1993,KWG),Cole et al(1994)and Baugh,Cole&Frenk (1996).To summarize:An algorithm based on an extension of the Press-Schechter theory due to Bower(1991)and to Bond et al(1991)is used to generate Monte Carlo realizations of the merging paths of dark matter halos from high redshift until the present.This algorithm allows all the progenitors of a present-day object,such as a cluster,to be traced back to arbitrarily early times.Dark matter halos are modelled as truncated isothermal spheres and it is assumed that as the halo forms,the gas relaxes to a distribution that exactly parallels that of the dark matter. Gas then cools and condenses onto a central galaxy at the core of each halo.Star formation and feedback processes take place as described in KWG(see also below).In practice,star formation in central galaxies takes place at a roughly constant rate of a few solar masses per year,in agreement with the rates derived by Kennicutt(1983)for normal spiral galaxies.As time proceeds,a halo will merge with a number of others,forming a new halo of larger mass.All gas which has not already cooled is assumed to be shock heated to the virial temperature of this new halo.This hot gas then cools onto the central galaxy of the new halo,which is identified with the central galaxy of its largest progenitor.The central galaxies of the other progenitors become satellite galaxies,which are able to merge with the central galaxy on a dynamical friction timescale.If a merger takes place between two galaxies of roughly comparable mass,the merger remnant is labelled as an“elliptical”and all cold gas is transformed instantaneously into stars in a“starburst”.Note that the infall of new gas onto satellite galaxies is not allowed,and star formation will continue in such objects only until their existing cold gas reservoirs are exhausted.Thus the epoch at which a galaxy is accreted by a larger halo delineates the transition between active star formation in the galaxy and passive evolution of its stellar population.The stellar populations of elliptical merger remnants in clusters hence redden as their stellar populations age.Central galaxy merger remnants in the“field”are able to accrete new gas in the form of a disk to form a“spiral”galaxy consisting of both a spheroidal bulge and a disk component.Note that as in KWG, we suppress the formation of visible stars in coolingflows within halos with V c>500km s−1 in order to avoid producing central cluster galaxies that are too bright and too blue.The cosmological initial conditions used in this paper are aσ8=0.67CDM universe withΩ=1and H0=50km s−1Mpc−1.Although this model does not match the COBE measurements of the amplitude of the microwave backgroundfluctuations,it has become the de facto standard for galaxy formation studies,since it provides a reasonablefit to observed small-scale galaxy clustering.2.2The chemical enrichment of galaxies in a hierarchical Universe In simple closed-box models of chemical evolution,all metals produced by stars are retained within the galaxy.After all the gas has been converted into stars,the metallicity of the galaxy is then simply given by the mass of metals produced per solar mass of long-lived stars that are formed.In our model,metals are exchanged between three components:stars,cold galactic gas,and hot halo gas.The routes through which this exchange may take place are the following:1.Stars−→hot and cold gas As decribed in KWG,the star formation rate in disk galaxiesis given by˙Mstars=αM cold/t dyn,(1) where M cold is the mass of cold gas in the galaxy,t dyn=R vir/10V c is a measure of the dynamical time of the galaxy(this assumes that the galaxy collapses by a factor10from the virial radius of the halo),andαis a free parameter.We assume that stars form witha standard Scalo(1986)IMF truncated at0.1and100M⊙and use the instantaneousrecycling approximation(e.g.Tinsley1980)to compute the amount of gas and metals returned to the interstellar medium and halo.A yield y of heavy elements is produced per solar mass of gas converted into stars.A fraction f of this yield is uniformly mixed with the hot gas in the halo,and the rest is uniformly mixed with the cold gas in the galaxy.The parameter f is introduced to allow for the possibility that heavy elements may be ejected directly into the halo in galactic fountains or chimneys resulting from the simultaneous explosions of tens or hundreds of supernovae(see Spitzer1990for a review).The gas fraction returned by evolved stars is estimated from the population synthesis models to be25%and is roughly independent of metallicity.This material is added to the cold gas component of the galaxy.2.Cold gas−→hot gas In our models,it is postulated that supernova explosions canrelease enough energy to drive cold gas into the halo.For a standard Scalo IMF,the number of supernovae expected per solar mass of stars formed isηSN≃5×10−3M−1⊙.The kinetic energy of the ejecta from each supernova is1051ergs.If a fractionǫof this energy is used to reheat cold gas to the virial temperature of the halo,the amount of cold gas lost to the intergalactic medium in time∆t may be estimated from simple energy balance arguments as∆M reheat=ǫ4V2c∆t(2)Hereǫis a free parameter controlling the efficiency of the feedback process.When cold gas is returned to the halo,it is assumed that its metals are uniformly mixed with the halo gas.3.Hot gas−→cold gas Metals present in hot halo gas may incorporated into a galaxywhen that gas is able to cool and condense at the centres of halos.The cooling rates in halos are calculated as described in KWG and are based on the model by White& Frenk(1991).The cooling functions vary according to the metallicity of the hot gas and are interpolated from Figure9.9of Binney&Tremaine(1987).4.Mixing during halo mergers As structure in the Universe builds up through hierarchicalclustering,dark matter halos merge and the metals contained in their hot gas compo-nents are mixed together.In this way,metals ejected by star-forming galaxies in the “field”at high redshift may end up contributing to the metals in the gas in rich clusters at z=0.5.Mixing during galaxy mergers When two galaxies merge within a common dark matterhalo,the metals contained in the cold gas and stars of both objects will be mixed in the merger remnant.We divide galaxy-galaxy merging events into two different classes:a) accretion events–this is when one galaxy is less than a third of the mass of the other one.b)major mergers–the galaxies are within a factor of three in mass.Major mergers are assumed to lead to the formation of elliptical galaxies.All the cold gas contained in the galaxies is turned into stars instantaneously in a“burst”and the enrichment during this phase is assumed to be a closed-box process,i.e.no metals escape from the galaxy.Accretion events do not induce any extra star formation.The metals present in the cold gas and stellar component of the satellite are simply added to the metals in the cold gas and stars of the central galaxy.Note that the factor of three is chosen so that the central galaxies of halos of circular velocity∼200km s−1will,on average,have bulge-to-disk ratios consistent with an Sbc-type spiral galaxy(see KWG).Our rules about star formation and enrichment during mergers and accretion events have been chosen for the sake of simplicity.They do not affect the results presented in this paper because,as we have mentioned,most stars in ellipticals do not form in these phases.To summarize,the main parameters of our model that control the metallicities of the stellar,cold gas and hot gas components in galaxies are the following:•Ωb the density of the Universe in baryons•αthe star formation efficiency•ǫthe feedback efficiency•y the yield of heavy elements(instantaneous recycling assumed)•f the fraction of heavy elements ejected directly into the hot halo gas withoutfirst being mixed with the cold gasAs in previous work(see KWG),we have adopted a“Milky Way”normalization,i.e.we tune the parameters so that the properties of the central galaxy in a halo of V c=220km s−1 match those of our own Galaxy.In practice,the tuning procedure operates as follows.Wefirst choose a value ofΩb.αandǫcontrol the luminosity and cold gas mass of the galaxy and are adjusted to obtain a B-band absolute magnitude of∼−20.5and a cold gas mass of6×109M⊙. The yield is chosen so that the galaxy has a V-light weighted mean metallicity of0.7solar,a value consistent with the mean observed metallicity of stars in the solar neighbourhood(see Tinsley1980and references therein).It should be noted that in our model,since metals are driven out of a galaxy by winds and diluted in the surrounding gas,the mean metallicity of the stars in a galaxy will always be lower than the yield y.The higher the feedback efficiency,the higher the value of y required to obtain a metallicity of0.7solar.The parameter f controls thetotal mass of metals contained in the hot halo gas.Since there are no reliable measurements of the metallicities of galactic halo gas(indeed,X-ray emission from hot gas around spiral galaxies has yet to be detected),we tune f to match the abundance of metals observed in the intracluster medium.A compilation of data by Arnaud et al(1992)shows that the Fe abundance in a sample of nearby clusters is∼0.3solar,with substantial scatter.We have thus chosen f so that the metallicity of the hot gas in halos of circular velocity1000km s−1 matches this value.Note that the properties of a Milky Way-type disk galaxies were explored in detail in a paper by Kauffmann(1996a)using a chemical evolution model very similar to the one described above.In that paper,it was demonstrated that the classic G-dwarf problem was solved by rapid early enrichment in the low mass objects that later merged to form the Galaxy,and that the predicted age-metallicity distribution of the stars in the Galactic disk agreed rather well with a recent compilation of data on solar neighbourhood stars.In Table1,we list parameter values for two representative models.Model A(or the strong feedback model)hasΩb=0.1.For our adopted Hubble Constant of50km s−1Mpc−1,this value lies at the upper end of the permitted range ofΩb according to current constraints from models of Big Bang nucleosynthesis(see Turner1996for a review),but at the lower end of measurements the fraction of baryons in rich clusters(White et al1993;White&Fabian 1995).Model A also has a high supernova feedback efficiency.The value of the yield(twice solar)is rather high,but still roughly consistent with theoretical calculations of the mass of different types of heavy elements ejected during Type II and Type Ia supernova explosions assuming a standard Salpeter IMF(Tsujimoto et al1995).Model B(or the weak feedback model)hasΩb=0.06.It has a considerably smaller feedback efficiency and yield.3The New Spectral Synthesis ModelsWe compute the spectrophotometric properties of model galaxies using new population synthe-sis models by Bruzual&Charlot(1997,in preparation).These span the range of metallicities 5×10−3≤Z/Z⊙≤5and include all phases of stellar evolution from the zero-age main sequence to supernova explosions for progenitors more massive than8M⊙,or the end of the white dwarf cooling sequence for less massive progenitors.The models are based on recent stellar evolutionary tracks computed by Alongi et al.(1993),Bressan et al.(1993),Fagotto et al.(1994a,b,c),and Girardi et al.(1996),supplemented with prescriptions for upper-AGB and post-AGB evolution.The radiative opacities are taken from Iglesias et al.(1992).In the version used here,we adopt the library of synthetic stellar spectra compiled by Lejeune et al. (1997b,in preparation;see also1997a)for all metallicities.This library is based on spectra by Kurucz(1995,private communication;see also Kurucz1992)for the hotter(O-K)stars, Bessell et al.(1989,1991)and Fluks et al.(1994)for M giants,and Allard&Hauschildt (1995)for M dwarfs.The Lejeune et al.spectral library also includes semi-empirical correc-tions for blanketing,a well-known limitation of synthetic spectra(see,for example,Charlot, Worthey&Bressan1996,and references therein).The resulting model spectra computed for stellar populations of various ages and metallicities have been checked against observed spectra of star clusters and galaxies(Bruzual&Charlot1997;Bruzual et al.1997).In addition,the models predict the strengths of21stellar absorption features,including the Mg2index near5000˚A that is often used as a spectral diagnostic in early-type galaxies.The predictions are computed using the Worthey et al.(1994)analyticfitting functions for index strength as a function of stellar temperature,gravity and metallicity that are calibrated empirically on a sample of460Galactic stars.This constitutes the standard“Lick/IDS”system,in which each index is defined by a central bandpass bracketted by two pseudo-continuum bandpasses.The integrated index of a stellar population is then computed by weighting the contributions from individual stars by their level of continuum(see Worthey et al.1994,and Bressan et al.1996for more detail).It is worth noting that the most massive elliptical galaxies exhibit[Mg/Fe]ratios in excess of that found in the most metal-rich stars in the solar neighborhood(by∼0.2−0.3dex;see Worthey,Faber,&Gonzalez1992).While this may limit the accuracy of the predicted Mg2indices of bright elliptical galaxies,the recent models of Bressan et al.(1997,in preparation)show convincingly that an enhancement in light elements atfixed total metallicity has virtually no effect on the other spectrophotometric properties of model stellar populations.A complete discussion of the differences between the spectrophotometric predictions of these models with those in previous studies will be presented in Bruzual&Charlot(1997). The typical discrepancies between the properties of stellar populations of the same input age and metallicity that are obtained by using the spectral synthesis models constructed by different groups of scientists,have already been illustrated by Charlot,Worthey&Bressan (1996).These can reach up to0.05mag in rest-frame B−V,0.25mag in rest-frame V−K and a25%dispersion in the V-band mass-to-light ratio.With these uncertainties in mind,we will concentrate more on understanding the trends seen in the observations than on obtaining exactfits to the data.4Theory of the origin of a mass-metallicity relation for ellipticalsAs was discussed previously,the assumption that supernova feedback ejects cold gas and metals from galaxies and that the efficiency of this process scales as1/V2c,where V c is the circular velocity of the galaxy,means that more massive and luminous disk galaxies will be more metal rich.Because of the1/V2c scaling,the metallicity-luminosity relation will saturate at large V c when the feedback efficiency becomes negligible and all gas and metals are retained in the galaxy.For large V c,galaxies are effectively closed boxes.Thus in our scenario,metals in the hot gas component,including the gas in rich clusters,are produced primarily by low-mass galaxies since these lose their gas very easily.In clusters,most of the enrichment takes place at high redshift before the cluster has assembled(see section8).Infigure1,we show the metallicity-luminosity relation for disk galaxies at z=0in our model.We have plotted the V-light weighted mean metallicities of the stars in these disks. The result for model A is shown as a solid line and that for B as a dashed line.As expected the relation rises much more steeply for model A,which has much more efficient feedback. In model B,the relation saturates at V-absolute magnitudes of around−20.The model A relation is in better qualitative agreement with the observed metallicity-luminosity relation of spiral galaxies(measured using emission lines from the gas in HII regions)since this shows no turnover(Roberts&Haynes1994).In the merger model,it is not a priori clear that ellipticals should also obey a metallicity-Figure1:The metallicity-luminosity relation for disk galaxies in the model:the V-luminosity weighted mean metallicity of the stars is plotted as a function of V-band absolute magnitude. The solid line is for the high feedback model A and the dashed line is for the low feedback model B.luminosity relation.For this to be the case,bright ellipticals have to be formed from the mergers of systematically bigger disks than faint ellipticals.Figure2demonstrates that this is indeed the case.We plot the mean progenitor mass of ellipticals in present-day clusters of circular velocity1000km s−1versus their stellar mass.The mean progenitor mass is computed by weighting each star in the galaxy by the mass of the disk-galaxy progenitor in which it formed and is expressed in units of the total mass of the elliptical.As can be seen, the progenitors of elliptical galaxies of2×1011M⊙are typically10times more massive than those of1010M⊙ellipticals.The error bars show the5th to95th percentile spread in mean progenitor mass among ellipticals in each mass bin.Infigure3,we show the metallicity-luminosity and age-luminosity relations for present-day cluster ellipticals.The left panel is for model A and the right panel is for model B.We plot V-light weighted stellar quantities as before.Note that the ages differ somewhat from those given in Kauffmann(1996b),because the V-light weighting has changed as a result of the implementation of the new spectral synthesis models.The rms scatter in age is1.2Gyear and the scatter in metallicity atfixed luminosity is0.14in solar units.Model A again has a much steeper metallicity-luminosity relation than model B.Both models show very little trend in age with luminosity.If anything,the brighter ellipticals have somewhat younger ages. We conclude,therefore,that in the hierarchical merger model,the observed colour-magnitude relation for elliptical galaxies must arise as a metallicity effect.。

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