A note on synchronization of a fractional order Coullet chaotic system
高级英语Book5学习资料lesson1
LessonOne Salvation1. 课文译文救赎兰斯顿.休斯在我快13岁那年,我的灵魂得到了拯救,然而并不是真正意义上的救赎。
事情是这样的。
那时我的阿姨里德所在的教堂正在举行一场盛大的宗教复兴晚会。
数个星期以来每个夜晚,人们在那里讲道,唱诵,祈祷。
连一些罪孽深重的人都获得了耶稣的救赎,教堂的成员一下子增多了。
就在复兴晚会结束之前,他们为孩子们举行了一次特殊的集会——把小羊羔带回羊圈。
里德阿姨数日之前就开始和我提这件事。
那天晚上,我和其他还没有得到主宽恕的小忏悔者们被送去坐在教堂前排,那是为祷告的人安排的座椅。
我的阿姨告诉我说:“当你看到耶稣的时候,你看见一道光,然后感觉心里似乎有什么发生。
从此以后耶稣就进入了你的生命,他将与你同在。
你能够看见、听到、感受到他和你的灵魂融为一体。
”我相信里德阿姨说的,许多老人都这么说,似乎她们都应该知道。
尽管教堂里面拥挤而闷热,我依然静静地坐在那里,等待耶稣的到来。
布道师祷告,富有节奏,非常精彩。
呻吟、喊叫、寂寞的呼喊,还有地狱中令人恐怖的画面。
然后他唱了一首赞美诗。
诗中描述了99只羊都安逸的待在圈里,唯有一只被冷落在外。
唱完后他说道:“难道你不来吗?不来到耶稣身旁吗?小羊羔们,难道你们不来吗?”他向坐在祷告席上的小忏悔者们打开了双臂,小女孩们开始哭了,她们中有一些很快跳了起来,跑了过去。
我们大多数仍然坐在那里。
许多长辈过来跪在我们的身边开始祷告。
老妇人的脸像煤炭一样黑,头上扎着辫子,老爷爷的手因长年的劳作而粗糙皲裂。
他们吟唱着“点燃微弱的灯,让可怜的灵魂得到救赎”的诗歌。
整个教堂里到处都是祈祷者的歌声。
最后其他所有小忏悔者们都去了圣坛上,得到了救赎,除了一个男孩和依然静静地坐着等侯的我。
那个男孩是一个守夜人的儿子,名字叫威斯特里。
在我们的周围尽是祈祷的修女、执事。
教堂里异常闷热,天色也越来越暗了。
最后威斯特里小声对我说:“去他妈的上帝。
我再也坐不住了,我们站起来吧,就可以得到救赎了。
高三英语艺术批评方法科学严谨运用单选题30题
高三英语艺术批评方法科学严谨运用单选题30题1. The artist's work is often described as _____, showing a unique blend of styles.A. revolutionaryB. conventionalC. mundaneD. derivative答案:A。
本题中,“revolutionary”意为“革命性的”,符合描述独特风格融合的艺术作品;“conventional”表示“传统的”,与独特风格不符;“mundane”意思是“平凡的,世俗的”,不能体现作品的独特;“derivative”指“模仿的,派生的”,不符合独特融合的特点。
2. The painting is criticized for being too _____, lacking depth and complexity.A. superficialB. profoundC. intricateD. elaborate答案:A。
“superficial”表示“肤浅的”,符合缺乏深度和复杂性的批评;“profound”意为“深刻的”,与批评内容相反;“intricate”指“复杂精细的”,不符合题意;“elaborate”意思是“精心制作的”,也不符合缺乏深度的描述。
3. The sculpture is praised for its _____ form, which catches theviewer's eye immediately.A. amorphousB. symmetricalC. asymmetricalD. chaotic答案:B。
“symmetrical”表示“对称的”,能让人眼前一亮;“amorphous”意为“无定形的”,通常不具备吸引眼球的特点;“asymmetrical”指“不对称的”,可能不够直接吸引;“chaotic”意思是“混乱的”,不符合吸引人的描述。
象征主义文学简介
象征主义文学简介阿洲整理象征主义文学是起源于19世纪中叶的法国,并于20世纪初期扩及欧美各国的一个文学流派,是象征主义思潮在文学上的体现,也是现代主义文学的一个核心分支,主要涵盖诗歌和戏剧两大领域,其影响力一直持续到今天。
西方主流学术界认为象征主义文学的诞生是古典文学和现代文学的分水岭。
法国诗人夏尔·波德莱尔和美国诗人爱伦·坡是象征主义的先驱。
尽管“象征主义”一词最早出现于1886年,但波德莱尔和爱伦·坡早在19世纪中叶的创作就最初涉及到了一些象征主义的理念。
一、概述(一)、什么是象征:象征(Symbol),在古希腊是指“拼凑”、“类比”。
最早指一块书板的两个半块,互相各取半块,作为信物。
逐渐用来指那些参加神秘活动的人借以互相秘密认识的一种标志、秘语或仪式。
象征就是指甲事物与乙事物有着重要的密切的关系,甲事物代表、暗示着乙事物。
在象征活动中,象征是用小事物来暗示、代表一个远远超出其自身涵义的大事物,如十字架-基督,用具体的人的感觉可以感知的物象来暗指某种抽象的不能感知的人类情感或观念,如狼-贪婪。
神话世界就是象征的世界,又因为神话是文学之母,所以文学与象征不可分离。
(二)、什么是象征主义:作为一种创作美学,象征主义古已有之,与浪漫主义、现实主义一道,是文学史上具有原型意义的三种基本创作美学。
始于柏拉图,他不统一的物质世界分为二元的现象世界和本体世界,现象世界是本体世界的模本。
欧美现代主义文学中最早出现的一个流派。
产生于19世纪中叶的法国,然后波及欧洲其他国家,至20世纪20年代,有了进一步发展,成为国际性文学流派。
反对肤浅的抒情和直露的说教,主张情与理的统一,通过象征、暗示、意象、隐喻、自由联想和语言的音乐性去表现理念世界的美和无限性,曲折地表达作者的思想和复杂微妙的情绪、感受。
(三)、概述:19世纪80年代中期在法国正式打出旗号的象征主义是对以孔德为代表的实证主义哲学和以左拉为代表的自然主义文学的反拨。
全程检测英语七年级上册a版
全程检测英语七年级上册a版全文共3篇示例,供读者参考篇1English Class and the Full Blast TextbookHey there! Let me tell you about my experience with the English textbook we're using this year - Full Blast 7 Student's Book A. As a seventh grader, learning English is pretty important, and this textbook has been quite a journey so far.When I first got my hands on the Full Blast book, I'll admit I was a bit intimidated. It's a thick book with a lot of pages and content. But as I started flipping through it, I realized it's actually really well-organized and engaging. The layouts are colorful and visually appealing, with lots of pictures, illustrations, and graphics that make it fun to work through.One thing I really like about Full Blast is how it's structured into units with different themes. Each unit covers a particular topic, like sports, technology, or the environment. This helps keep things interesting because you're always learning about something new. And within each unit, there's a good variety ofactivities - reading passages, listening exercises, grammar practice, writing tasks, and more.The reading texts are probably my favorite part. They're just the right level of challenge for a seventh grader like me. Not too easy, but also not mind-bendingly difficult. The topics are pretty cool too, ranging from articles about extreme sports to stories set in different cultures around the world. After the readings, there are comprehension questions to test how well you understood, as well as vocabulary exercises to build your word power.The listening portions are great for practicing thoseall-important listening skills. There are recordings of conversations, announcements, and other audio material. Sometimes it's tricky to catch everything at first, but the exercises allow you to listen multiple times and really train your ear. My teacher is good about going over the tough parts too.For grammar, the book covers all the basics like verb tenses, parts of speech, and sentence structure. But it doesn't just throw a bunch of boring grammar rules at you. There are lots of examples, practice activities, and even some fun comics to illustrate the concepts. The writing sections build on thegrammar, giving you frameworks for different types of writing like emails, stories, and persuasive essays.What I maybe like least are the speaking exercises because, you know, as a shy seventh grader the idea of talking out loud in English is still pretty nerve-wracking! But I know it's important practice. The role-plays and dialogues in the book do start to make it feel more natural over time.There are also sections focused on developing broader skills like critical thinking, research, note-taking, and giving presentations. These are hard but useful skills to work on. And I appreciate that the book has a multi-skillssection in each unit that combines reading, writing, listening, and speaking into bigger projects.Overall, I'd say Full Blast does a good job of making English class engaging while still covering all the key skills we need to learn. Is it always easy? No way. Is it always fun? Well, it's still school. But the textbook makes the journey of learning English about as enjoyable as it could be.There's a nice mix of interactive material, clear instruction, real-world topics and themes, and lots of opportunity to practice.I feel like I've improved my English abilities quite a bit since starting the book. And hey, even if English class can be a grindsometimes, at least I'm getting a solid education about the language.I've got to wrap this up because I've got English homework to do (shocking, I know!) But that's my take on the Full Blast 7 textbook we're using. It's a quality resource that makes the most of seventh grade English instruction. Until next time!篇2My Journey with the "All-through English" TextbookAs a seventh-grader, the "All-through English for Grade 7, Volume A" textbook has been my constant companion in navigating the exciting, yet sometimes daunting, world of English language learning. This textbook, with its vibrant colors and engaging illustrations, has not only been a source of knowledge but also a gateway to broadening my horizons and fostering a deeper appreciation for diverse cultures.From the moment I cracked open its pages, I was immediately captivated by the well-structured layout and the thoughtful organization of the units. Each unit presents a central theme, skillfully woven through a variety of engaging tasks, vocabulary exercises, and stimulating reading passages. The themes range from exploring different hobbies and interests todelving into environmental issues and appreciating cultural diversity – all of which have been instrumental in expanding my understanding of the world around me.One aspect that truly sets this textbook apart is the emphasis on developing all four language skills: listening, speaking, reading, and writing. The listening exercises, accompanied by authentic dialogues and narratives, have honed my ear for different accents and intonations, preparing me for real-life conversations. The speaking activities, ranging from role-plays to group discussions, have given me the confidence to express myself freely and articulately in English.The reading passages have been a treasure trove of knowledge, introducing me to a myriad of topics, from ancient civilizations to cutting-edge technologies. Each passage is meticulously crafted, with a gradual increase in complexity, ensuring that my reading comprehension skills are continuously challenged and refined. The accompanying questions and exercises have taught me valuable strategies for understanding complex texts, such as identifying main ideas, making inferences, and drawing conclusions.However, it is the writing section that has truly transformed my relationship with the English language. The textbookprovides a structured approach to developing writing skills, guiding me through the process of brainstorming, organizing ideas, and composing coherent and well-structured pieces. From crafting persuasive essays to creative narratives, I have learned to express my thoughts and emotions with clarity and precision.Moreover, the textbook's emphasis on grammar and vocabulary has been invaluable. The dedicated grammar sections have demystified the intricacies of English syntax, while the vocabulary exercises have enriched my lexical repertoire, enabling me to communicate with greater precision and nuance.Beyond academics, this textbook has also fostered a deeper appreciation for cultural diversity. The inclusion of authentic texts, dialogues, and cultural notes has exposed me to various traditions, customs, and perspectives from around the globe. This exposure has not only broadened my understanding but has also instilled in me a profound respect for different ways of life.As I near the end of this textbook, I can't help but reflect on the incredible journey it has taken me on. From the initial trepidation of tackling a new language to the current confidence and proficiency I possess, this textbook has been an indispensable companion. It has not only equipped me with the necessary skills to excel in English but has also cultivated a lovefor language learning and a curiosity to explore the world beyond my immediate surroundings.Looking ahead, I eagerly anticipate the next volume of the "All-through English" series, as it promises to take me on yet another exhilarating adventure in the realm of language and culture. With this textbook by my side, I am confident that my English proficiency will continue to soar, opening doors to new opportunities and enabling me to communicate effectively in an increasingly interconnected world.篇3Ah, the dreaded English textbook series we all love to hate –Full-term English Detection. As a bright-eyed and bushy-tailed 7th grader just starting out on this multi-year journey, I can already feel the impending sense of dread creeping up my spine. But alas, such is the life of a middle schooler trying to trudge through the murky waters of mandatory English education.Volume 1, Version A was our first introduction to this tome of torment. It came adorned with a snazzy cover depicting students in varied states of engagement and disengagement, no doubt foreshadowing the emotional rollercoaster we were all about to embark upon. The first few units started off relativelytame, easing us in with simple conversational phrases and vocabulary fitting for pre-teens. Fodder for starting to "detect" English, I suppose.But then the real fun began. Suddenly we were bombarded with increasingly complex grammar rules, tenses, and structure –all looming like a thick fog of confusion ready to envelop our pubescent minds. The examples progressively became more obscure and irrelevant to our actual lived experiences as middle schoolers. When would we really need to discuss negotiating trade deals or the migratory patterns of arctic waterfowl?The reading comprehension passages were a beast all their own. What sadistic collector of literature decided that snippets about defunct Mesopotamian civilizations or the contributing factors behind the Dissolution of the Monasteries would be appropriate for 12-year-old non-native speakers? These intense bouts of highly scholastic content were then followed up with even more grammar analysis and rote memorization of vocabulary lists spanning multiple pages. It was a vicious cycle not for the faint of heart.Group activities and pairwork exercises did provide a brief reprise from the onslaught of deluge. At least we could struggle and stumble through the nonsensical dialogues together,giggling at our botched pronunciations and inevitable failures to grasp the material fully. These tiny shreds of social interaction scattered around the units acted as life rafts, keeping our motivation for continuing semi-afloat.The workbooks, oh those thrice-damned workbooks, were their own recurring nightmare. Rows upon rows ofmind-numbing fill-in-the-blanks and mad-lib styled sentence completions. Had we been enrolled in an English cloistered monastery training to become grammarian-linguists, such an intense paper ration may have been justified. But for the rest of us mere temporarily-perceived laypeople, it always felt like an exercise in excessive academic flagellation.Don't even get me started on the audio materials, which always seemed to feature an overenthusiastic and gratingly cheery British narrator spouting off these inane dialogues with her wildly affected accent at a pace far too rapid for our underdeveloped auditory processing skills. The recordings may as well have been beamed in from an alternate universe.It's hard to articulate the true anguish and sense of helplessness we felt slogging through each chapter of Full-term English Detection Grade 7 Volume 1 Version A. The tears, thetantrums, the crushing blows to our fragile pre-teen egos – all seemingly par for the course with this curriculum.Yet, as much as we cringed, cried, and wanted to take that cursed textbook out behind the bike shed for a Old Yeller-style termination of its misery, I must admit there was a tadbit of backhanded merit to the approach. Nobody could accuse it of being an "easy A" - we certainly had to work our little buns off. And I'd be lying if I said my English language foundations and fundamentals didn't level up at least a smidge after completing that inaugural volume.Perhaps the real value of such a mentally груелинговый experience was theitud tempering it produced within us former students. Not only did we build up our lingual core strength through Volume 1's exercises, but we also developed a ferocious sense of determination and grit. If we could persevere through that convoluted and unnecessarily elevated curriculum, then we could withstand pretty much any intellectual hazing the future had in store.So love it or hate it (and most of us vacillated between those two poles on an hourly basis), Full-term English Detection Grade 7 Volume 1 Version A was the trial by fire that molded us. We may have emerged from that first textbook frazzled, frayed, andquestioning all our life choices, but goddammit we made it through to the other side. Battered, bruised, but never broken – a badge of honor we semi-literate anglophiles would wear forever after.。
托福阅读TPO14答案解析
托福阅读答案1.prestige威望,声望,所以B的status正确。
原句说在很多地方马已经成为了什么的象征,后面一个让步说尽管牛羊也很重要,应该是说马更重要才对,所以兴趣的动物,利益的动物和要求的动物都不对。
2.以most mobile and most militarilistic做关键词定位至倒数第三句,说以马匹做运输工具和福利使得Inner Eurasia pastoralism最mobile,答案是B,C虽然提到了welfare,但不是 borrow的,所以不选。
3.profound深远的,所以答案far-reaching正确,选D。
原句说pastoralism的出现和发展对欧亚大陆内部有什么样的影响,后面又加了这个区域之外的欧洲和亚洲,所以应该是影响范围广大,所以答案是D。
C说反,后面都说了indirect;A奇特的B正面的没说。
4.首先找到对比,本段前两句分别说了游牧民族和定居民族的特点,一是依靠动物及其食物,一是驯养动物。
紧接着说了这种对比的结果,也就是作者做这个对比的目的。
游牧民族就像食肉动物一样,在食物链中占据了较高的等级,所以需要更多地盘。
所以对比的目的就是解释为什么游牧民族需要占领更多地方,答案是A。
此题特殊,修辞目的在修辞点所在句子后面,需要多加注意。
5.问题当中关键词难找,但可以从上题pastoralist和agriculturalist的对比,也就是本段的第一二两句中得出答案D,说游牧民族经常四处游走。
A和C原文都没说,B项与原文说反,原文第四句说游牧民族必须四处走以保证同样量的food and clothing,所以B错。
6.首先以Eastern Europe和Mongolia做关键词定位至第四句,原句单纯讲述了一个例子,所以往前看,前句说由于游牧民族的存在,出现了很大一块地域范围内共享相似的生态上的,文化上的甚至语言上的特点。
紧接着就说了语言上的一个例子,所以语言的这个例子是为了证明前文的,答案是D。
剑桥雅思阅读10真题解析(test2)
剑桥雅思阅读10真题解析(test2)雅思阅读部分的真题资料,同学们需要进行一些细致的总结,比如说解析其实就是很重要的内容,接下来就是店铺给同学们带来的关于剑桥雅思阅读10真题解析(test2)的内容,一起来详细的分析一下吧,希望对你们的备考有所帮助。
剑桥雅思阅读10原文(test2)READING PASSAGE 1You should spend about 20 minutes on Questions 1-13, which are based on Reading Passage 1 on the following pages.Questions 1-7Reading Passage 1 has seven paragraphs, A-G.Choose the correct heading for each paragraph from the list of headings below.Write the correct number,i-ix,in boxes 1-7 on your answer sheetList of Headingsi The search for the reasons for an increase in populationii Industrialisation and the fear of unemploymentiii The development of cities in Japaniv The time and place of the Industrial Revolutionv The cases of Holland, France and Chinavi Changes in drinking habits in Britainvii Two keys to Britain’s industrial revolutionviii Conditions required for industrialisationix Comparisons with Japan lead to the answer1 Paragraph A2 Paragraph B3 Paragraph C4 Paragraph D5 Paragraph E6 Paragraph F7 Paragraph GTea and the Industrial RevolutionA Cambridge professor says that a change in drinking babits was the reason for the Industrial Revolution in Britain. Anjana Abuja reportsA Alan Macfarlane, professor of anthropological science at King’s College, Cambridge, has, like other historians, spent decades wrestling with the enigma of the Industrial Revolution. Why did this particular Big Bang — the world-changing birth of industry — happen in Britain? And why did it strike at the end of the 18th century?B Macfarlane compares the puzzle to a combination lock. ‘There are about 20 different factors and all of them need to be present before the revolution can happen,’ he says. For industry to take off, there needs to be the technology and power to drive factories, large urban populations to provide cheap labour, easy transport to move goods around, an affluent middle-class willing to buy mass-produced objects, a market-driven economy and a political system that allows this to happen. While this was the case for England, other nations, such as Japan, the Netherlands and France also met some of these criteria but were not industrialising. ‘All these factors must have been necessary but not sufficient to c ause the revolution,’ says Macfarlane. ‘After all, Holland had everything except coal while China also had many of these factors. Most historians are convinced there are one or two missing factors that you need to open the lock.’C The missing factors, he proposes, are to be found in almost even kitchen curpboard. Tea and beer, two of the nation’sfavourite drinks, fuelled the revolution. The antiseptic properties of tannin, the active ingredient in tea, and of hops in beer — plus the fact that both are made with boiled water — allowed urban communities to flourish at close quarters without succumbing to water-borne diseases such as dysentery. The theory sounds eccentric but once he starts to explain the detective work that went into his deduction, the scepticism gives way to wary admiration. Macfarlane’s case has been strengthened by support from notable quarters — Roy Porter, the distinguished medical historian, recently wrote a favourable appraisal of his research.D Macfarlane had wondered for a long time how the Industrial Revolution came about. Historians had alighted on one interesting factor around the mid-18th century that required explanation. Between about 1650 and 1740,the population in Britain was static. But then there was a burst in population growth. Macfarlane says: ‘The infant mortality rate halved in the space of 20 years, and this happened in both rural areas and cities, and across all classes. People suggested four possible causes. Was there a sudden change in the viruses and bacteria around? Unlikely. Was there a revolution in medical science? But this was a century before Lister’s revolution_ Was there a change in environmental conditions? There were improvements in agriculture that wiped out malaria, but these were small gains. Sanitation did not become widespread until the 19th century. The only option left is food. But the height and weight statistics show a decline. So the food must have got worse. Efforts to explain this sudden reduction in child deaths appeared to draw a blank.’E This population burst seemed to happen at just the right time to provide labour for the Industrial Revolution. ‘When youstart moving towards an industrial revolution, it is economically efficient to have people living close together,’ says Macfarlane. ‘But then you get disease, particularly from human waste.’ Some digging around in historical records revealed that there was a change in the incidence of water-borne disease at that time, especially dysentery. Macfarlane deduced that whatever the British were drinking must have been important in regulating disease. He says, ‘We drank beer. For a long time, the English were protected by the strong antibacterial agent in hops, which were added to help preserve the beer. But in the late 17th century a tax was introduced on malt, the basic ingredient of beer. The poor turned to water and gin and in the 1720s the mortality rate began to rise again. Then it suddenly dropped again. What caused this?’F Macfarlane looked to Japan, which was also developing large cities about the same time, and also had no sanitation. Water-borne diseases had a much looser grip on the Japanese population than those in Britain. Could it be the prevalence of tea in their culture? Macfarlane then noted that the history of tea in Britain provided an extraordinary coincidence of dates. Tea was relatively expensive until Britain started a direct clipper trade with China in the early 18th century. By the 1740s, about the time that infant mortality was dipping, the drink was common. Macfarlane guessed that the fact that water had to be boiled, together with the stomach-purifying properties of tea meant that the breast milk provided by mothers was healthier than it had ever been. No other European nation sipped tea like the British, which, by Macfarla ne’s logic, pushed these other countries out of contention for the revolution.G But, if tea is a factor in the combination lock, why didn’tJapan forge ahead in a tea-soaked industrial revolution of its own? Macfarlane notes that even though 17th-century Japan had large cities, high literacy rates, even a futures market, it had turned its back on the essence of any work-based revolution by giving up labour-saving devices such as animals, afraid that they would put people out of work. So, the nation that we now think of as one of the most technologically advanced entered the 19th century having ‘abandoned the wheel’._oseph Lister was the first doctor to use antiseptic techniques during surgical operations to prevent infections.Questions 8-13Do the following statements agree with the information given in Reading Passage 1?In boxes 8-13 on your answer sheet, writeTRUE if the statement agrees with the informationFALSE if the statement contradicts the informationNOT GIVEN if there is no information on this8 China’s transport system was not suitable for industry in the 18th century.9 Tea and beer both helped to prevent dysentery in Britain.10 Roy Porter disagrees with Professor Macfarlane’s findings.11 After 1740,there was a reduction in population in Britain.12 People in Britain used to make beer at home.13 The tax on malt indirectly caused a rise in the death rate.READING PASSAGE 2You should spend about 20 minutes on Questions 14-26, which are based on Reading Passage 2 below.Gifted children and learningA Internationally, ‘giftedness’ is most frequentlydetermined by a score on a general intelligence test, known as an IQ test, which is above a chosen cutoff point, usually at around the top 2-5%. Children’s educational environment contributes to the IQ score and the way intelligence is used. For example, a very close positive relationship was found when children’s IQ scores were compared with their home educational provision (Freeman, 2010). The higher the children’s IQ scores, especially over IQ 130, the better the quality of their educational backup, measured in terms of reported verbal interactions with parents, number of books and activities in their home etc. Because IQ tests are decidedly influenced by what the child has learned, they are to some extent measures of current achievement based on age-norms; that is, how well the children have learned to manipulate their knowledge and know-how within the terms of the test. The vocabulary aspect, for example, is dependent on having heard those words. But IQ tests can neither identify the processes of learning and thinking nor predict creativity.B Excellence does not emerge without appropriate help. To reach an exceptionally high standard in any area very able children need the means to learn, which includes material to work with and focused challenging tuition — and the encouragement to follow their dream. There appears to be a qualitative difference in the way the intellectually highly able think, compared with more average-ability or older pupils, for whom external regulation by the teacher often compensates for lack of internal regulation. To be at their most effective in their self-regulation, all children can be helped to identify their own ways of learning —metacognition —which will include strategies of planning, monitoring, evaluation, and choice of what to learn. Emotional awareness is also part of metacognition, so children should behelped to be aware of their feelings around the area to be learned, feelings of curiosity or confidence, for example.C High achievers have been found to use self-regulatory learning strategies more often and more effectively than lower achievers, and are better able to transfer these strategies to deal with unfamiliar tasks. This happens to such a high degree in some children that they appear to be demonstrating talent in particular areas. Overviewing research on the thinking process of highly able children, (Shore and Kanevsky, 1993) put the instructor’s problem succinctly: ‘If they [the gifted] merely think mo re quickly, then we need only teach more quickly. If they merely make fewer errors, then we can shorten the practice’. But of course, this is not entirely the case; adjustments have to be made in methods of learning and teaching, to take account of the many ways individuals think.D Yet in order to learn by themselves, the gifted do need some support from their teachers. Conversely, teachers who have a tendency to ‘overdirect’ can diminish their gifted pupils’ learning autonomy. Although ‘spoon-feeding’ can produce extremely high examination results, these are not always followed by equally impressive life successes. Too much dependence on the teachers risks loss of autonomy and motivation to discover. However, when teachers help pupils to reflect on their own learning and thinking activities, they increase their pupils’ self-regulation. For a young child, it may be just the simple question ‘What have you learned today?’ which helps them to recognise what they are doing. Given that a fundamental goal of education is to transfer the control of learning from teachers to pupils, improving pupils’ learning to learn techniques should be a major outcome of the school experience,especially for the highly competent. There are quite a number of new methods which can help, such as child-initiated learning, ability-peer tutoring, etc. Such practices have been found to be particularly useful for bright children from deprived areas.E But scientific progress is not all theoretical, knowledge is a so vital to outstanding performance: individuals who know a great deal about a specific domain will achieve at a higher level than those who do not (Elshout, 1995). Research with creative scientists by Simonton (1988) brought him to the conclusion that above a certain high level, characteristics such as independence seemed to contribute more to reaching the highest levels of expertise than intellectual skills, due to the great demands of effort and time needed for learning and practice. Creativity in all forms can be seen as expertise mixed with a high level of motivation (Weisberg, 1993).F To sum up, learning is affected by emotions of both the individual and significant others. Positive emotions facilitate the creative aspects of learning and negative emotions inhibit it. Fear, for example, can limit the development of curiosity, which is a strong force in scientific advance, because it motivates problem-solving behaviour. In Boekaerts’ (1991) review of emotion the learning of very high IQ and highly achieving children, she found emotional forces in harness. They were not only curious, but often had a strong desire to control their environment, improve their learning efficiency and increase their own learning resources.Questions 14-17Reading Passage 2 has six paragraphs, A-F.Which paragraph contains the following information?Write the correct letter, A-F, in boxes 14-17 on your answersheet.NB You may use any letter more than once.14 a reference to the influence of the domestic background on the gifted child15 reference to what can be lost if learners are given too much guidance16 a reference to the damaging effects of anxiety17 examples of classroom techniques which favour socially-disadvantaged childrenQuestions 18-22Look at the following statements (Questions 18-22) and the list of people below.Match each statement with the correct person or people, A-E.Write the correct letter, A-E, in boxes 18-22 on your answer sheet.18 Less time can be spent on exercises with gifted pupils who produce accurate work.19 Self-reliance is a valuable tool that helps gifted students reach their goals.20 Gifted children know how to channel their feelings to assist their learning.21 The very gifted child benefits from appropriate support from close relatives.22 Really successful students have learnt a considerable amount about their subject.List of PeopleA FreemanB Shore and KanevskyC ElshoutD SimontonE BoekaertsQuestions 23-26Complete the sentences below.Choose NO MORE THAN TWO WORDS from the passage for each answer.Write your answers in boxes 23-26 on your answer sheet23 One study found a strong connection between children’s IQ and the availability of andat home.24 Children of average ability seem to need more direction from teachers because they do not have25 Metacognition involves children understanding their own learning strategies, as well as developing26 Teachers who rely on what is known as often produce sets of impressive grades in class tests.READING PASSAGE 3You should spend about 20 minutes on Questions 27-40, which are based on Reading Passage 3 below.Museums of fine art and their publicThe fact that people go to the Louvre museum in Paris to see the original painting Mona Lisa when they can see a reproduction anywhere leads us to question some assumptions about the role of museums of fine art in today’s worldOne of the most famous works of art in the world is Leonardo da Vinci’s Mona Lisa. Nearly everyone who goes to see the original will already be familiar with it from reproductions, but they accept that fine art is more rewardingly viewed in its original form.However, if Mona Lisa was a famous novel, few people wouldbother to go to a museum to read the writer’s actual manuscript rather than a printed reproduction. This might be explained by the fact that the novel has evolved precisely because of technological developments that made it possible to print out huge numbers of texts, whereas oil paintings have always been produced as unique objects. In addition, it could be argued that the practice of interpre ting or ‘reading’ each medium follows different conventions. With novels, the reader attends mainly to the meaning of words rather than the way they are printed on the page, whereas the ‘reader’ of a painting must attend just as closely to the material form of marks and shapes in the picture as to any ideas they may signify.Yet it has always been possible to make very accurate facsimiles of pretty well any fine art work. The seven surviving versions of Mona Lisa bear witness to the fact that in the 16th century, artists seemed perfectly content to assign the reproduction of their creations to their workshop apprentices as regular ‘bread and butter’ work. And today the task of reproducing pictures is incomparably more simple and reliable, with reprographic techniques that allow the production of high-quality prints made exactly to the original scale, with faithful colour values, and even with duplication of the surface relief of the painting.But despite an implicit recognition that the spread of good reproductions can be culturally valuable, museums continue to promote the special status of original work.Unfortunately, this seems to place severe limitations on the kind of experience offered to visitors.One limitation is related to the way the museum presents its exhibits. As repositories of unique historical objects, art museumsare often called ‘treasure houses’. We are reminded of this even before we view a collection by the presence of security guards, attendants, ropes and display cases to keep us away from the exhibits. In many cases, the architectural style of the building further reinforces that notion. In addition, a major collection like that of London’s National Gallery is housed in numerous rooms, each with dozens of works, any one of which is likely to be worth more than all the average visitor possesses. In a society that judges the personal status of the individual so much by their material worth, it is therefore difficult not to be impressed by one’s own relative ‘worthlessness’ in such a n environment.Furthermore, consideration of the ‘value’ of the original work in its treasure house setting impresses upon the viewer that, since these works were originally produced, they have been assigned a huge monetary value by some person or institution more powerful than themselves. Evidently, nothing the viewer thinks about the work is going to alter that value, and so today’s viewer is deterred from trying to extend that spontaneous, immediate, self-reliant kind of reading which would originally have met the work.The visitor may then be struck by the strangeness of seeing such diverse paintings, drawings and sculptures brought together in an environment for which they were not originally created. This ‘displacement effect’ is further heightened by the sheer volume of exhibits. In the case of a major collection, there are probably more works on display than we could realistically view in weeks or even months.This is particularly distressing because time seems to be a vital factor in the appreciation of all art forms. A fundamental difference between paintings and other art forms is that there isno prescribed time over which a painting is viewed. By contrast, the audience encounters an opera or a play over a specific time, which is the duration of the performance. Similarly, novels and poems are read in a prescribed temporal sequence, whereas a picture has no clear place at which to start viewing, or at which to finish. Thus art works themselves encourage us to view them superficially, without appreciating the richness of detail and labour that is involved.Consequently, the dominant critical approach becomes that of the art historian, a specialised academic approach devoted to ‘discovering the meaning’ of art within the cultural context of its time. T his is in perfect harmony with the museum’s function, since the approach is dedicated to seeking out and conserving ‘authentic’, ‘original’ readings of the exhibits. Again, this seems to put paid to that spontaneous, participatory criticism which can be found in abundance in criticism of classic works of literature, but is absent from most art history.The displays of art museums serve as a warning of what critical practices can emerge when spontaneous criticism is suppressed. The museum public, like any other audience, experience art more rewardingly when given the confidence to express their views. If appropriate works of fine art could be rendered permanently accessible to the public by means of high-fidelity reproductions, as literature and music already are, the public may feel somewhat less in awe of them. Unfortunately, that may be too much to ask from those who seek to maintain and control the art establishment.Questions 27-31Complete the summary using the list of words, A-L, below.Write the correct letter, A-L, in boxes 27-31 on your answersheet.The value attached to original works of artPeople go to art museums because they accept the value of seeing an original work of art. But they do not go to museums to read original manuscripts of novels, perhaps because the availability of novels has depended on 27 for so long, and also because with novels, the 28 are the most important thing.However, in historical times artists such as Leonardo were happy to instruct 29 to produce copies of their work and these days new methods of reproduction allow excellent replication of surface relief features as well as colour and 30It is regrettable that museums still promote the superiority of original works of art, since this may not be in the interests of the 31A institutionB mass productionC mechanical processesD publicE paintsF artistG size H underlying ideas I basic technologyJ readers K picture frames L assistantsQuestions 32-35Choose the correct letter, A, B, C or D.Write the correct letter in boxes 32-35 on your answer sheet32 The writer mentions London’s National Gallery to illustrateA the undesirable cost to a nation of maintaining a huge collection of art.B the conflict that may arise in society between financial and artistic values.C the n egative effect a museum can have on visitors’ opinions of themselves.D the need to put individual well-being above large-scaleartistic schemes.33 The writer says that today, viewers may be unwilling to criticise a work becauseA they lack the knowledge needed to support an opinion.B they fear it may have financial implications.C they have no real concept of the work’s value.D they feel their personal reaction is of no significance.34 According to the writer, the ‘displacement effect’ on the visitor is caused byA the variety of works on display and the way they are arranged.B the impossibility of viewing particular works of art over a long period.C the similar nature of the paintings and the lack of great works.D the inappropriate nature of the individual works selected for exhibition.35 The writer says that unlike other forms of art, a painting does notA involve direct contact with an audience.B require a specific location for a performance.C need the involvement of other professionals.D have a specific beginning or end.Questions 36-42Do the following statements agree with the views of the writer in Reading Passage 3?In boxes 36-40 on your answer sheet, writeYES if the statement agrees with the views of the writerNO if the statement contradicts the views of the writerNOT GIVEN if it is impossible to say what the writer thinksabout this36 Art history should focus on discovering the meaning of art using a range of media.37 The approach of art historians conflicts with that of art museums.38 People should be encouraged to give their opinions openly on works of art.39 Reproductions of fine art should only be sold to the public if they are of high quality.40 In the future, those with power are likely to encourage more people to enjoy art.剑桥雅思阅读10原文参考译文(test2)Passage 1参考译文:茶与工业革命一个剑桥教授称英国工业革命的导火索是饮水习性的改变。
the nature of scientific reasoning
本次翻译练习的难度比较大,文章出自北京师范大学研究生英语阅读与翻译课程所用的授课材料,作者布洛诺夫斯基是英国著名的数学家和散文家,剑桥大学数学博士。
这篇文章从科学发展史的角度出发,论述的问题主要是科学并不排斥想象力和创造力。
因此标题翻译成“科学理性的本质”或“科学推理的本质”是比较恰当的。
要翻译好这篇文章不仅应在在宏观的层面牢牢把握文章的主旨,也需要从微观的角度考虑作者使用的语言在语法和修辞上的特点,这样才能在理解的基础上恰当的表达。
当然,这篇文章相对于大家目前的英语水平,在理解和表达两个方面都具有不小的挑战性。
下面通过对这次翻译比较好的赵新平同学作业的点评,来分段落说一说这篇文章究竟有哪些细节部分需要注意,以及相应的翻译策略。
1What is the insight in which the scientist tries to see into nature? Can it indeed be called either imaginative or creative? To the literary man the question may seem merely silly. He has been taught that science is a large collection of facts; and if this is true, then the only seeing which scientists need to do is, he supposes, seeing the facts. He pictures them, the colorless professionals of science, going off to work in the morning into the universe in a neutral, unexposed state. They then expose themselves like a photographic plate. And then in the darkroom or laboratory they develop the image, so that suddenly and startlingly it appears, printed in capital letters, as a new formula for atomic energy.原译:什么是洞察力?科学家一直试图弄清它的本质。
中央财经大学
10
Children born to serve the country (cont.d)
• Maintained the birth rate to maintain military power
Until 30 years old all men lived in one house and were not full-fledged citizens free to live with their wives, to make clandestine marriage instill an early burning love Physical training of bare boys and girls together in a place to draw and allure young men to marry while men who would not marry walked bare outside. Fathers of 3 exempt from military service The state would find another younger mate for a childless wife. • No jealousy • Children were not private to any men but common to the common
中国经济与管理研究院
March 28 & April 6 & 13, 2008 2008年3月28日和4月6和13日
1
Socrates (苏格拉底)
Taught, but not for money like the Sophists. Like the Sophists’, his pupils were from aristocratic party. Taught and sought knowledge by the method of dialectic (question & answer, first practiced by Zeno 芝诺) in dialogues
高中英语试卷试题及答案
高中英语试卷试题及答案一、听力理解(共20分)1. What is the man doing now?A. Reading a book.B. Watching TV.C. Cooking dinner.答案:B2. What does the woman mean?A. She will go to the party.B. She has to work.C. She is not interested in the party.答案:C3. How much will the man pay for the tickets?A. $20B. $40C. $60答案:A二、阅读理解(共30分)Passage 1In this passage, the author discusses the importance of environmental protection. The text highlights the consequences of pollution and the need for sustainable practices.4. What is the main idea of the passage?A. The effects of pollution on wildlife.B. The benefits of sustainable living.C. The importance of environmental protection.答案:C5. According to the passage, which of the following is a result of pollution?A. Increased rainfall.B. Loss of biodiversity.C. Improved air quality.答案:BPassage 2This passage describes the history and cultural significance of a famous monument.6. When was the monument first constructed?A. In the 15th century.B. In the 16th century.C. In the 17th century.答案:A7. What is the primary purpose of the monument?A. To commemorate a historical event.B. To serve as a place of worship.C. To honor a famous person.答案:A三、完形填空(共20分)8. The word "spectacular" in the sentence "The view from the top of the mountain was spectacular" most closely means:A. DullB. OrdinaryC. Amazing答案:C9. In the context of the story, the character's decision to leave was:A. SpontaneousB. PlannedC. Forced答案:A10. The phrase "make a difference" in the last paragraph suggests that the character's actions:A. Had no impact.B. Were insignificant.C. Were influential.答案:C四、语法填空(共15分)11. The book, ________ I had read, was very interesting.答案:which12. She is the only person ________ has ever climbed the mountain.答案:who13. If you ________ earlier, you would have caught the train.答案:had left五、短文改错(共15分)14. The following is a short passage with ten errors. Identify and correct the errors.Original: I have a lot of friend who are very kind. They always help me when I am in trouble. One of the most important thing in life is to have good friend.Corrected: I have a lot of friends who are very kind. They always help me when I am in trouble. One of the most important things in life is to have good friends.六、书面表达(共20分)15. Write an essay of about 120 words on the topic "The Role of Technology in Education." Begin your essay with a brief description of the current situation and then discuss the benefits and potential drawbacks of using technology in the classroom. Finally, give your opinion on whether technology should be more widely adopted in schools.答案:[学生作文]注意:以上试题及答案为示例,实际考试内容可能有所不同。
托福听力tpo61 lecture1、2、3 原文+题目+答案+译文
托福听力tpo61lecture1、2、3原文+题目+答案+译文Lecture1 (1)原文 (1)题目 (3)答案 (5)译文 (5)Lecture2 (7)原文 (7)题目 (9)答案 (11)译文 (11)Lecture3 (13)原文 (13)题目 (15)答案 (17)译文 (17)Lecture1原文Listen to part of a lecture in a sociology class.Sociology is really a cross disciplinary field.We find that elements of biology, psychology,and other sciences often overlap as we study particular phenomena.So let me introduce a concept from cognitive psychology.Okay,let's say someone asks you to look at a list and memorize as many items on it as you can.Most of us are able to remember,on average,seven items.There are several variations of this memory test.And the results consistently show that the human limit for short term memoryis seven bits of Information.This limit is called channel capacity.Channel capacity is the amount of information that can be transmitted or received over a specific connection,like our brain and the channel capacity for our short-term memory.It has some interesting real-life implications,like phone numbers.Local numbers here in the United States all have seven digits,because the phone companies realized early on that longer numbers would lead to a lot more wrong numbers being dialed.But the idea of channel capacity doesn't apply just to our cognitive abilities.It also affects our relationships with people around us.Psychologists talk about sympathy groups.These are the people,close friends,family to whom we devote the most time.We call or see them frequently,we think about them,worry about them.And studies show for each of us,the size of that group is about10to15people.But why so small?sure.Relationships take time and emotional energy.And most of us don't have unlimited amounts of either.But what if there's another reason?what if it's our brain that setting the limit?And in fact,there's evidence that indicates that our social channel capacity may actually be a function of our brain size,or more accurately,the size of our neocortex.The neocortex is the frontal region in the brain of mammals that's associated with complex thought.Primates have the largest neocortex is among mammals,but among different primate species,humans,apes,baboons, neocortex size varies.A lot of theories have been proposed for these variations.Like maybe it's related to the use of tools,but no theories ever seemed like a perfect explanation.Until the late1990s,what an anthropologist named Robin Dunbar published an article about his studies of primates.Dunbar theory is that if you look at any particular species of primate,you'll find that if it has a larger neocortex that it lives in a larger social group.Take human beings,we have the largest neocortices and we have the largest number of social relationships.So we've said that our sympathy group is10to15people.What about our other relationships other than family and close friends,such as those that occur in the workplace will call these social groups as opposed to sympathy groups?How many relationships can we handle there?Those relationships aren't as involved,so we can handle more of them.But is there an upper limit?well,Dunbar says that there is,and he developed an equation to calculate it.His equation depends on knowing the ratio between the size of the neocortex and the size of the whole brain.That is of the whole brain,what percentage of it is taken up by the neocortex?Once you know the average percentage for any particular species,the equation predicts the expected maximum social group size for that species.For humans,that number seems to be about150. So according to Dunbar’s equation,our social groups probably won't number more than150people.Now,Dunbar’s hypothesis isn't the kind of thing that's easy to confirm in a controlled experiment,but there is anecdotal evidence to support it.As part of his research,Dunbar reviewed historical records for21different traditional hunter gatherer societies.And those records showed that the average number of people in each village was just under150,148.4to be exact.Dunbar also worked with biologists to see if his hypothesis applies to other mammals besides primates. When they looked at meat eating mammals,carnivores,they found that the ones with a larger neocortex also have a bigger social group.And the number of individuals in that group is predicted by Dunbar’s equation supporting his hypothesis. But when they looked at insectivores,mammals that eat insects,the results were inconsistent.The data didn't disprove Dunbar’s hypothesis,but wasn't a nice,neat match like the carnivore studies,which isn't totally surprising.Insectivores are hard to observe,since many of them only come out at night or they spend a lot of time underground.So,we know a lot less about their social relationships.题目1.What is the lecture mainly about?A.The role that the neocortex plays in human memoryB.The connection between neocortex size and social relationships in mammalsC.Various studies that compare social group sizes in humans and other mammalsD.Ways that humans can expand the size of their social groups2.Why does the professor discuss the length of some telephone numbers?A.To show that real-world applications are informed by cognitive psychologyB.To point out an exception to a well-known principle about memoryC.To explain why telephone numbers are used in tests of memoryD.To explain why people often dial the wrong telephone number3.What does the professor imply about the size of a person's sympathy group?A.It closely matches the size of the person's family.B.It becomes larger when a person learns how to feel compassion for others.C.It may not be something a person makes a conscious decision to control.D.It may not be as predictable as the size of the person's social group.4.What did Dunbar's study of the records of some traditional hunter-gatherer societies indicate?A.Hunter-gatherer societies were the first to form social groups.B.Tool usage by humans is related to social group size.C.There is a maximum social group size for humans.D.Hunter-gatherers tend to have smaller-sized social groups.5.What does the professor say that biologists discovered in their research of animals other than primates?A.Dunbar's hypothesis accurately predicts social group sizes for all animals.B.Social group sizes of carnivores are more difficult to predict than those of insectivores.C.Data on insectivore behavior neither support nor contradict Dunbar's hypothesis.D.The size of an animal's neocortex is affected by its diet.6.Why does the professor say this:But why so small?sure.Relationships take time and emotional energy.And most of us don't have unlimited amounts of either.A.To encourage students to spend more time developing relationshipsB.To emphasize that her point is based on personal experienceC.To indicate that she realizes that the students already know the answer to her questionD.To suggest that there is more than one possible response to her question答案B AC C C D译文请听社会学课上的部分内容。
托福测试题及答案
托福测试题及答案一、听力理解(Listening Comprehension)1. What is the main topic of the lecture?A. The history of photographyB. The impact of technology on artC. The role of photography in journalismD. The evolution of camera technologyAnswer: B2. According to the professor, what is one of the benefits of digital photography?A. It allows for greater artistic control.B. It is less expensive than film photography.C. It is easier to manipulate images.D. It requires less technical skill.Answer: A3. Why does the professor mention the example of the painter who used a camera?A. To illustrate the limitations of photographyB. To show how technology can inspire traditional art formsC. To demonstrate the influence of photography on paintingD. To argue that photography is a form of artAnswer: B4. What does the student imply about the relationship between photography and journalism?A. They are becoming more distinct from each other.B. They have always been closely related.C. They are merging due to technological advancements.D. They are separate fields with little overlap.Answer: C二、阅读理解(Reading Comprehension)Passage 1: The Impact of Technology on Education5. What is the author's main argument in the passage?A. Technology has had a negative impact on education.B. The integration of technology in education is essentialfor its future.C. Technology has made education less personal.D. The benefits of technology in education are overstated. Answer: B6. According to the passage, which of the following is NOT a benefit of using technology in the classroom?A. Increased student engagementB. Access to a wider range of resourcesC. Improved test scoresD. Enhanced communication between students and teachers Answer: C7. The author cites the example of online courses toillustrate:A. The accessibility of education to a broader audience.B. The potential for personalized learning experiences.C. The challenges of maintaining student motivation.D. The need for traditional classroom settings.Answer: APassage 2: The History of Urban Planning8. What is the primary focus of the passage?A. The evolution of urban planning over time.B. The role of government in urban development.C. The impact of urban planning on society.D. The challenges faced by urban planners.Answer: A9. The author mentions ancient Rome to demonstrate:A. The early origins of urban planning.B. The influence of urban planning on architecture.C. The importance of public spaces in cities.D. The limitations of early urban planning techniques. Answer: A10. What does the passage suggest about modern urban planning?A. It is more focused on aesthetics than functionality.B. It has become more inclusive and sustainable.C. It is primarily driven by economic considerations.D. It has largely abandoned traditional planning principles.Answer: B三、口语表达(Speaking Expression)Task 1: Describe a memorable event from your childhood.Sample Response:One of the most memorable events from my childhood was the summer I spent at my grandparents' farm. I was about ten years old at the time. The experience was incredibly enriching as I learned about farming, the importance of hard work, and the beauty of nature. It was a time filled with laughter, new discoveries, and a deep connection with my family.Task 2: Explain why you think environmental conservation is important.Sample Response:Environmental conservation is crucial for several reasons. Firstly, it ensures the preservation of natural resources for future generations. Secondly, it helps maintain biodiversity, which is vital for the balance of ecosystems. Lastly, conservation efforts contribute to combating climate change by reducing pollution and promoting sustainable practices. It is our collective responsibility to protect the environment for the well-being of all living beings on Earth.四、写作任务(Writing Task)Task 1: Write an essay discussing the advantages and disadvantages of social media.Sample Essay:Social media has revolutionized the way we communicate and access information. On the positive side, it allows for instant connectivity with people around the world, fosters communities with shared interests, and provides a platform for self-expression and creativity. However, it also has its downsides, such as the spread of misinformation, the potential for cyberbullying, and the negative impact on mental health due to social comparison. Balancing the benefits and drawbacks is key to harnessing the power of social media responsibly.Task 2: Propose a solution to a local environmental issue in your community.Sample Essay:One pressing environmental issue in our community is the excessive use of single-use plastics. To address this, I propose the implementation of a local ordinance that bans single-use plastic items, such as straws and bags, and encourages the use of reusable alternatives. Additionally, educational campaigns can raise awareness about the environmental impact of plastic waste. By working together, our community can significantly reduce its。
tpo37三篇阅读原文译文题目答案译文背景知识
tpo37三篇阅读原文译文题目答案译文背景知识阅读-1 (2)原文 (2)译文 (3)题目 (4)答案 (10)背景知识 (10)阅读-2 (11)原文 (11)译文 (13)题目 (14)答案 (19)背景知识 (19)阅读-3 (20)原文 (21)译文 (22)题目 (23)答案 (29)背景知识 (29)阅读-1原文Thales And The Milesians①While many other observers and thinkers had laid the groundwork for science, Thales(circa624B.C.E-ca547B.C.E.),the best known of the earliest Greek philosophers,made the first steps toward a new,more objective approach to finding out about the world.He posed a very basic question:"What is the world made of?"Many others had asked the same question before him,but Thales based his answer strictly on what he had observed and what he could reason out-not on imaginative stories about the gods or the supernatural.He proposed water as the single substance from which everything in the world was made and developed a model of the universe with Earth as a flat disk floating in water.②Like most of the great Greek philosophers,Thales had an influence on others around him.His two best-known followers,though there were undoubtedly others who attained less renown,were Anaximander and Anaximenes.Both were also from Miletus(located on the southern coast of present-day Turkey)and so,like Thales,were members of the Milesian School.Much more is known about Anaximander than about Anaximenes,probably because Anaximander,who was born sometime around610B.C.E,ambitiously attempted to write a comprehensive history of the universe.As would later happen between another teacher-student pair of philosophers,Plato and Aristotle,Anaximander disagreed with his teacher despite his respect for him.He doubted that the world and all its contents could be made of water and proposed instead a formless and unobservable substance he called"apeiron"that was the source of all matter.③Anaximander's most important contributions,though,were in other areas. Although he did not accept that water was the prime element,he did believe that all life originated in the sea,and he was thus one of the first to conceive of this important idea.Anaximander is credited with drawing up the first world map of the Greeks and also with recognizing that Earth's surface was curved.He believed, though,that the shape of Earth was that of a cylinder rather than the sphere that later Greek philosophers would conjecture.Anaximander,observing the motions of the heavens around the polestar,was probably the first of the Greek philosophers to picture the sky as sphere completely surrounding Earth-an idea that,elaborated upon later,would prevail until the advent of the Scientific Revolution in the seventeenth century.④Unfortunately,most of Anaximander's written history of the universe was lost, and only a few fragments survive today.Little is known about his other ideas. Unfortunately,too,most of the written work for Anaximenes,who may have been Anaximander's pupil,has also been lost.All we can say for certain about Anaximenes,who was probably born around560BCE,is that following in the tradition of Anaximander,he also disagreed with his mentor.The world,according to Anaximenes,was not composed of either water or apeiron,but air itself was the fundamental element of the pressed,it became water and earth, and when rarefied or thinned out,it heated up to become fire.Anaximenes may have also been the first to study rainbows and speculate upon their natural rather than supernatural cause.⑤With the door opened by Thales and the other early philosophers of Milestus, Greek thinkers began to speculate about the nature of the universe.This exciting burst of intellectual activity was for the most part purely creative.The Greeks,from Thales to Plato and Aristotle,were philosophers and not scientists in today's sense. It is possible for anyone to create"ideas"about the nature and structure of the universe,for instance,and many times these ideas can be so consistent and elaborately structured,or just so apparently obvious,that they can be persuasive to many people.A scientific theory about the universe,however,demands much more than the various observations and analogies that were woven together to form systems of reasoning,carefully constructed as they were,that would eventually culminate in Aristotle's model of the world and the universe.Without experimentation and objective,critical testing of their theories,the best these thinkers could hope to achieve was some internally consistent speculation that covered all the bases and satisfied the demands of reason.译文泰勒斯和米利西亚人①当许多其他观察家和思想家为科学奠定基础时,泰勒斯(约公元前624年-约公元前547年),最著名的古希腊哲学家,迈出了探索世界的更客观的新方法的第一步。
(2024年高考真题含解析)2024年北京市普通高中学业水平等级性考试英语试卷(含解析)
2024年普通高等学校招生全国统一考试北京卷英语试卷养成良好的答题习惯,是决定成败的决定性因素之一。
做题前,要认真阅读题目要求、题干和选项,并对答案内容作出合理预测;答题时,切忌跟着感觉走,最好按照题目序号来做,不会的或存在疑问的,要做好标记,要善于发现,找到题目的题眼所在,规范答题,书写工整;答题完毕时,要认真检查,查漏补缺,纠正错误。
第一部分知识运用(共两节,30分)第一节(共10小题;每小题 1. 5分,共15分)阅读下面短文,掌握其大意,从每题所给的A、B、C、D 四个选项中,选出最佳选项。
I’d just arrived at school, ready for another school day. I was reading a book in the classroom when there was an 1 . “Today at 1: 10 there will be auditions (面试) for a musical.” My friends all jumped up in excitement and asked me, “Will you be going, Amy?” “Sure,” I said. I had no 2 in drama, but I’d try out because my friends were doing it.At 1:10, there was a 3 outside the drama room. Everyone looked energetic. I hadn’t expected I’d be standing there that morning. But now that I was doing it, I 4 felt nervous. What if I wasn’t any good?I entered the room and the teachers made me say some lines from the musical. They then 5 my singing skills and asked what role I wanted to play. The teachers were smiling and praising me. I felt like I had a 6 , so I said, “A big role.” They said they’d look into it. I started getting really nervous. What if I didn’t get a main role?Soon, the cast list was 7 . My friends checked and came back shouting, “Amy, you got the main role!” Sure enough, my name was at the top. I just stared at it and started to 8 . I was so happy.After two months we were all prepared and ready to go on stage. It was fun. And when people started 9 , that gave me a boost of confidence. It stayed with me and made me feel 10 . I realised that by trying something new, I can have fun — even if it means stepping out of my comfort zone.1.A.assignment B.initiative C.announcement D.interview2.A.hesitancy B.interest C.worry D.regret3.A.game B.show C.play D.line4.A.suddenly B.continuously C.originally D.generally5.A.advertised B.tested C.challenged D.polished6.A.demand B.credit C.dream D.chance7.A.traded B.posted C.questioned D.claimed8.A.well up B.roll in C.stand out D.go off9.A.whispering B.arguing C.clapping D.stretching10.A.funnier B.fairer C.cleverer D.braver第二节(共10小题;每小题1. 5分,共15分)A阅读下列短文,根据短文内容填空。
跟他有什么关系 英语作文
跟他有什么关系英语作文Title: The Significance of Connection: Exploring Relationships in "What's the Matter with Him?"In the narrative "What's the Matter with Him?" by an unnamed author, the central theme revolves around the complexities of human relationships and the significance of connection. The story delves into the dynamics between characters, particularly focusing on the protagonist and their interaction with another individual. Through various encounters and exchanges, the narrative unfolds layers of meaning regarding the nature of relationships and the impact they have on individuals. This essay aims to dissect the significance of the relationship between the protagonist and the other character, exploring its relevance and implications within the context of the story.First and foremost, the relationship between the protagonist and the other character serves as a catalystfor personal growth and introspection. Interactions withothers often provide opportunities for self-reflection, allowing individuals to gain insights into their own thoughts, feelings, and behaviors. In "What's the Matterwith Him?", the protagonist's encounters with the other character prompt moments of introspection, leading to a deeper understanding of oneself and one's place in the world. Through these interactions, the protagonist grapples with questions of identity, belonging, and purpose, ultimately undergoing a transformative journey of self-discovery.Furthermore, the relationship between the protagonist and the other character highlights the interconnectednessof human experiences. Despite differences in background, personality, and circumstance, the characters in the story are bound together by shared experiences and emotions. Through their interactions, they navigate themes of empathy, compassion, and understanding, bridging the gap betweentheir individual worlds. In doing so, the narrative emphasizes the universal nature of human connection, illustrating how relationships have the power to transcend barriers and unite individuals in a common humanity.Moreover, the relationship between the protagonist and the other character serves as a lens through which larger societal issues are examined. Within the narrative, the characters grapple with issues of prejudice, discrimination, and social inequality, reflecting broader systemic challenges within society. Through their interactions, the story sheds light on the complexities of these issues, highlighting the ways in which interpersonal relationships intersect with larger social structures. By exploring the dynamics between the characters, the narrative prompts readers to confront their own biases and assumptions, fostering greater awareness and understanding of the world around them.In conclusion, the relationship between the protagonist and the other character in "What's the Matter with Him?" is of significant importance within the narrative, serving asa catalyst for personal growth, a reflection of interconnected human experiences, and a lens through which larger societal issues are examined. Through their interactions, the characters navigate themes of identity,empathy, and social inequality, ultimately contributing to a richer understanding of the complexities of human relationships and the world in which they unfold. As the story unfolds, it becomes evident that the significance of this relationship extends far beyond the confines of its fictional setting, resonating with readers on a deeply personal and universal level.。
总结作者观点的英语作文
In the realm of essay writing,summarizing an authors viewpoint is a critical skill that allows readers to grasp the essence of the work without delving into the entire text. Heres a detailed approach to crafting an English essay that encapsulates the authors perspective:1.Introduction:Begin with a brief introduction to the author and the work being discussed.Provide the title of the book or article,the authors name,and the context in which it was written.This sets the stage for the reader to understand the background of the work.2.Thematic Overview:Next,present a thematic overview of the work.This should include the main themes or topics that the author explores.Its important to note that this is not a summary of the plot or events but rather an outline of the central ideas.3.Authors Perspective:Dive into the authors viewpoint.This is the core of your essay. Explain the authors stance on the themes or issues e direct quotes from the text to support your analysis,ensuring that you cite these appropriately.4.Supporting Arguments:Discuss the arguments or evidence the author uses to support their viewpoint.This may include statistical data,historical references,personal anecdotes,or logical reasoning.Analyze how these elements contribute to the authors perspective.5.Counterarguments and Objections:If applicable,address any counterarguments or objections that the author acknowledges and how they respond to them.This shows the depth of the authors thought process and their engagement with different viewpoints.6.Authors Style and Tone:Comment on the authors writing style and tone.How do these elements contribute to the effectiveness of their argument?Are they persuasive, analytical,or emotive?Discuss how the style and tone influence the readers perception of the authors viewpoint.7.Conclusion:Conclude your essay by summarizing the authors main points and reiterating their perspective.Reflect on the significance of their viewpoint and its implications for the reader or the broader context of the discussion.8.Personal Reflection:Optionally,you may include a brief personal reflection on the authors viewpoint.This can be a few sentences where you express your agreement or disagreement with the author,or how their perspective has influenced your own thinking.9.Citations and References:Ensure that you properly cite all quotes and references from the original work.This not only gives credit to the author but also adds credibility to your essay.10.Proofreading:Finally,proofread your essay for grammatical errors,clarity,and coherence.A wellwritten essay not only conveys the authors viewpoint accurately but also does so in a manner that is engaging and easy to understand.Remember,the goal of summarizing an authors viewpoint in an essay is to provide a clear and concise understanding of their perspective,supported by evidence from the text, while also demonstrating your own analytical skills.。
小学上册第9次英语第三单元真题试卷
小学上册英语第三单元真题试卷英语试题一、综合题(本题有100小题,每小题1分,共100分.每小题不选、错误,均不给分)1.The library has many ______. (books)2.Renaissance artists like Leonardo da Vinci created famous works like the ______ (蒙娜丽莎).3.The elephant is very ___. (big)4.My brother likes to solve ____ (math problems).5.In an electrochemical cell, oxidation occurs at the ____ electrode.6.I can ______ (骑) a bike without training wheels.7.What is the name of the famous American national park known for its canyons?A. YellowstoneB. Grand CanyonC. YosemiteD. ZionB8.What do we call a large body of freshwater?A. OceanB. RiverC. LakeD. Sea9.The house is ___. (colorful)10.The chemical formula for magnesium oxide is __________.11.I call my pet bird “.”12.We are ______ (going) to the zoo this Saturday.13.The _____ (rose) symbolizes love.14.The _____ (cabbage) is fresh.15.The river is ___. (wide)16.He is reading a ______. (book)17.My cousin is studying to be a __________ (医生).18.My friend is a _____ (心理学家) who helps children.19.The book is ________ and interesting.20.The pH scale measures how _______ or basic a solution is.21.The chemical formula for sodium phosphate is ______.22.What do you call a bird that cannot fly?A. SparrowB. OstrichC. EagleD. Penguin23. A chemical change is often irreversible, while a physical change is ______.24.What do you call the season when leaves fall?A. WinterB. SummerC. SpringD. Fall25.What is the capital of Russia?A. MoscowB. St. PetersburgC. KazanD. Novosibirsk26.I can ______ (解决) problems creatively.27.I can play with my ________ (玩具类型) anywhere.28.Chemical changes can produce new ________.29.The __________ (历史的工具) enable better analysis.30.The ______ (海豹) loves to bask in the sun.31.I love taking care of my ______ (植物) and watching them grow.32.Chemical reactions can be affected by _____, concentration, and surface area.33.My family has a pet _______ (动物). Its name is _______ (名字). It loves to _______ (动词) around the house.34.We can _______ a picnic by the lake.35.The ______ is very charismatic.36.What is the opposite of big?A. LargeB. HugeC. SmallD. Tall37.What is the main ingredient in bread?A. SugarB. FlourC. WaterD. YeastB38.The mantis shrimp has powerful ________________ (爪).39.The study of how landforms are created is called ______.40.At home, I would create a cozy ______ for my pet. I would fill it with soft ______ and toys to keep it happy. Every day, I would make sure to feed it healthy ______ and give it plenty of water.41.I like to draw pictures of ______ (动物) and give them to my friends.42.What is the term for a baby seal?A. PupB. CalfC. KitD. KidA43.What do you call the art of folding paper?A. PaintingB. SculptingC. OrigamiD. DrawingC44.The capital of the Netherlands is __________.45.My uncle is a __________ (科研人员).46.What do we call the place where we watch movies?A. TheaterB. ParkC. MallD. Playground47.What do you call the story of someone's life?A. NovelB. BiographyC. FantasyD. PoemB48.The ______ (小鹿) grazes peacefully, unaware of the approaching ______ (危险).49.The ________ (交通安全) is a priority for everyone.50.What do you call the season when it snows?A. SpringB. SummerC. FallD. Winter51.When I grow up, I want to be a ________ (科学家) and discover new ________ (东西).52.The first successful polio vaccine was developed by ________.53.What do you call the bright light produced by a firefly?A. GlowB. ShineC. SparkleD. FlickerA54.What is the term for a baby kangaroo?A. JoeyB. CalfC. CubD. KitA Joey55.What color do you get by mixing blue and yellow?A. GreenB. PurpleC. OrangeD. RedA56.The __________ is an important region for agriculture. (平原)57.My sister's favorite animal is a ______ (海龟).58.Which of these animals is a marsupial?A. KangarooB. LionC. ElephantD. Giraffe59.The ______ (花粉) is vital for plant reproduction.60.We had ______ (fun) at the amusement park.61. A ________ (森林) can be home to many species.62. A solution can be made more concentrated by adding more ______.63.In _____ (澳大利亚), you can find the Outback.64.They are going to ______ (visit) their grandma.65.My brother bought a new _______ (我哥哥买了一个新的_______).66.The __________ (文化差异) foster understanding.67.I appreciate all the ______ (帮助) my parents give me. Their support means a lot to me.68.I like to help my mom ________ (种花) in the garden.69.I enjoy learning new ______ (单词) in English. It helps me communicate better with others.70.Gravity is stronger on planets with more ______.71.The __________ (种植者) planted seeds in rows.72.The chemical process of photosynthesis converts sunlight into _____.73.What is the capital of Costa Rica?A. San JoséB. AlajuelaC. CartagoD. HerediaA74.What is the capital of France?A. RomeB. ParisC. BerlinD. Madrid75.The _____ (小猫) loves to play with balls of yarn.76.The turtle is very _______ (耐心).77.What do we call the process of water turning into ice?A. MeltingB. FreezingC. EvaporatingD. Condensing78.How many days are in a week?A. 5B. 6C. 7D. 8C79.I like to share my toy ________ (玩具名称) with my cousins.80.The Earth's surface is shaped by both ______ and human activity.81.What do you call a collection of maps?A. AtlasB. BookC. EncyclopediaD. DictionaryA82.How many months have 28 days?A. OneB. TwoC. AllD. TwelveC83.I like to ________ in the morning.84.Did you see that _____ (老虎) at the zoo?85.In a reaction, the rate can be affected by the surface area of the _____.86.The playground is _______ with children.87.What is the value of 7 × 2 3?A. 11B. 12C. 13D. 14A88.The chemical formula for magnesium sulfate is _____.89.What do we call an animal that primarily eats meat?A. HerbivoreB. OmnivoreC. CarnivoreD. Insectivore90.The ________ (土著文化) is fascinating to learn about.91.The chemical structure of DNA contains ______ bases.92.What do we call the central part of an atom?A. ElectronB. ProtonC. NucleusD. NeutronC93.What is the name of the famous artist known for his sculptures?A. MichelangeloB. RembrandtC. Van GoghD. RenoirA94.What is the main source of light during the day?A. MoonB. StarsC. SunD. Lamp95.What is the opposite of light?A. BrightB. HeavyC. DarkD. ClearC96.What do we call a story that is told through dialogue and action?A. NovelB. PlayC. PoemD. Short Story97.The mountains are _____ (tall/short) and beautiful.98.The first country to adopt a national anthem was _______. (荷兰)99.Saturn has over known ______.100.I love to watch ________ (舞蹈表演) on TV.。
小学上册P卷英语第6单元真题[含答案]
小学上册英语第6单元真题[含答案]英语试题一、综合题(本题有100小题,每小题1分,共100分.每小题不选、错误,均不给分)1. A dilute solution has a ______ concentration of solute.2.The _____ (dolphin) is swimming.3.What is the main purpose of a map?A. To tell timeB. To find directionsC. To play gamesD. To show pictures答案:B4.The ________ was a key event in the development of democracy.5.The chemical formula for magnesium sulfate is _______.6.My dog enjoys playing with other ______ (狗).7.Which month comes after May?A. AprilB. JuneC. JulyD. August8. A ______ has a symbiotic relationship with flowers.9.Gandhi is known for leading India to ________ from British rule.10.What is the main ingredient in mayonnaise?A. OilB. VinegarC. Egg yolkD. Sugar11.The __________ is a region characterized by its lush vegetation.12.What do we call a young turtle?A. HatchlingB. PupC. KitD. Chick答案:A Hatchling13.What is the capital city of Finland?A. HelsinkiB. TampereC. OuluD. Espoo14.What do we call the process of a seed growing into a plant?A. GerminationB. PollinationC. FertilizationD. Photosynthesis答案:A15.I like to play ________ with my friends after school.16.What fruit is known for having seeds on the outside?A. AppleB. StrawberryC. GrapeD. Cherry答案:B17.My _______ (金鱼) swims in a bowl.18.Where do we keep our clothes?A. DrawerB. FridgeC. OvenD. Sink19.The owl is a _______ (神秘的) night hunter.20. (66) is known for its ancient ruins. The ____21.Pressure can affect the ________ of gases.22.Acids tend to turn blue litmus paper _____.23. A __________ is a reaction that involves oxidation and reduction.24.The _______ of a wave can be affected by its wavelength.25.Cacti are examples of plants that store _____ (水).26.I enjoy ________ (玩耍) with my friends.27.What is the capital of South Africa?A. Cape TownB. PretoriaC. JohannesburgD. Durban答案:B28.The ______ is an excellent athlete.29.The _____ (海洋) is vast and deep.30.province) is a division of a country. The ____31.The rabbit is ______ (hopping) through the grass.32.In space, there is no air or ______.33.How do you say "school" in Spanish?A. EscuelaB. ÉcoleC. SchuleD. Scuola34. A magnet can attract ______ (metal) objects.35.The __________ (历史的趋势) predicts future paths.36. A ____(flood) occurs when water covers land that is usually dry.37.The weather is ________ today.38.The __________ (历史的价值观) reflect societal beliefs.39.What is the term for a baby rat?A. PupB. KitC. CalfD. Chick答案:A40.Acids taste _____ and can turn blue litmus paper red.41.What do we call the time it takes for the Earth to complete one rotation?A. YearB. DayC. MonthD. Hour答案:B42.Which shape has four equal sides?A. RectangleB. TriangleC. SquareD. Circle答案:C Square43.I have a ________ that plays music.44. A sound's frequency determines its ______.45.We enjoy ______ (参观) new places.46.What do we call a group of flamingos?A. PlumpB. StandC. FlockD. Colony答案:C Flock47.What do we call the imaginary line that divides the Earth into northern and southern hemispheres?A. EquatorB. Prime MeridianC. Tropic of CancerD. Tropic of Capricorn答案:A48.What is the main ingredient in lasagna?A. PastaB. RiceC. BreadD. Tortilla答案:A49.What do you call the natural satellite of the Earth?A. SunB. MoonC. StarD. Planet50.The __________ (科技进步) drive change.51.My __________ (玩具名) helps me learn about __________ (名词).52.What is the most popular fruit in the world?A. BananaB. AppleC. OrangeD. Grape答案:B Apple53. A ________ (金鱼) swims gracefully in its bowl.54.I want to _____ (write) a story.55. A mixture that contains two or more phases is called a ______.56.What do you call a person who performs magic tricks?A. MagicianB. IllusionistC. ClownD. Juggler答案:A57.What do bees make?A. HoneyB. MilkC. BreadD. Butter答案:A58. A light-year is a measure of ______.59.The frog croaks loudly during the ______ (春天).60. A ______ plays a key role in the habitat.61.The __________ (历史的多重解读) enrich our knowledge.62.What do you call the act of giving birth to animals?A. BreedingB. LayingC. HatchingD. All of the above63.I have ___ (three) pets.64.The state of matter that has a definite shape and volume is ______.65.The weather is very ___. (nice)66.The country known for its ice hockey is ________ (加拿大).67.Which animal is known for building dams?A. BeaverB. SquirrelC. RabbitD. Fox68.What instrument is used to measure temperature?A. BarometerB. ThermometerC. RulerD. Compass答案:B69.I can make a __________ (名词) with my __________ (玩具名).70.My grandma makes the best ______ (饼干). I love to help her in the ______ (厨房).71. A _____ (植物观察日记) can document growth and care.72.The invention of the calculator changed how people _____.73.My sister likes to draw ____.74.What is the name of the famous sculpture in New York Harbor?A. The ThinkerB. DavidC. Statue of LibertyD. Venus de Milo答案:C Statue of Liberty75.Each time I play, I discover something new about my ________ (玩具名) and how to use it.76.Which planet is known as the Red Planet?A. VenusB. MarsC. JupiterD. Saturn答案:B77.Water is made up of hydrogen and ______.78.What is the name of the famous painting by Leonardo da Vinci?A. The Last SupperB. Starry NightC. The ScreamD. Girl with a Pearl Earring答案:A79.What do we call the study of plants?A. ZoologyB. BotanyC. ChemistryD. Geography答案:B80.What do you call a young whale?A. CalfB. PupC. KitD. Lamb81.The ______ (小鸟) flutters its wings, ready to take flight.82.She enjoys ________.83.How many colors are in a rainbow?A. FiveB. SixC. SevenD. Eight84.We are having a ______ (field trip) to the zoo.85.I want to _____ (go/stay) home.86.What is the name of the famous American holiday celebrated on July 4th?A. ThanksgivingB. Independence DayC. Memorial DayD. Labor Day答案:B87. A ____(biosphere) is a global sum of all ecosystems.88.The __________ was so bright that I had to wear sunglasses. (阳光)89.What do we call the act of looking after children?A. ParentingB. NurturingC. CaringD. Raising答案:A Parenting90.The __________ (历史的回响) echoes through time.91.What is the name of our nearest star?A. Alpha CentauriB. Proxima CentauriC. SiriusD. Betelgeuse92.The ____ has bright feathers and often sings sweetly.93.Can you see the ________?94.Which season is the coldest?A. SpringB. SummerC. FallD. Winter95.Which planet is closest to the sun?A. MercuryB. VenusC. EarthD. Mars96.The beach is ___ (sandy/rocky).97.My friend is a _____ (心理学家) working with teens.98.The ________ (pumpkin) is orange and round.99.The amount of matter in an object is referred to as its _____ (mass).100.The chemical formula for water is _____.。
Gravity on Conformal Superspace
a r X i v :g r -q c /0311034v 1 11 N o v 2003Gravity on Conformal SuperspaceBryan KelleherThesis submitted in fulfillment of the requirements of the degree of Doctor of Philosophy from the Department of PhysicsUniversity College CorkNational University of Ireland,CorkSupervisor :Prof.Niall ´OMurchadha June 2003To my familyAcknowledgementsThere are many people I wish to thank.Firstly,Niall,go raibh m´ıle,m´ıle maith agat.It has been both a pleasure and a privilege.Thanks to the entire physics department for everything over the years-great times,a superb atmosphere and lifelong st -but most definitely not least-thanks to my parents,my brothers and sister,my wife to be Gill and my extended family and friends.I could not(and more than likely would not)have done it without you.AbstractThe configuration space of general relativity is superspace-the space of all Riemannian 3-metrics modulo diffeomorphisms.However,it has been argued that the configuration space for gravity should be conformal superspace-the space of all Riemannian3-metrics modulo diffeomorphisms and conformal transformations.Taking this conformal nature seriously leads to a new theory of gravity which although very similar to general relativity has some very different features particularly in cosmology and quantisation.It should reproduce the standard tests of general relativity.The cosmology is studied in some detail.The theory is incredibly restrictive and as a result admits an extremely limited number of possible solutions.The problems of the standard cosmology are addressed and most remarkably the cosmological constant problem is resolved in a natural way. The theory also has several attractive features with regard to quantisation particularly regarding the problem of time.Contents1Introduction11.1Introduction (1)1.2General Relativity (2)1.3(3+1)-Decomposition (2)1.4York’s Approach (5)1.4.1Gauge Fixing in GR (6)1.5Lagrangian and Hamiltonian Formulations (7)1.5.1The Lagrangian (7)1.5.2Constraints and Evolution Equations (9)1.5.3The Hamiltonian (11)1.6Jacobi Action (11)1.7Conformally Related Solutions (12)1.8Topological Considerations (14)1.8.1Integral Inconsistencies (14)1.9Other Results (18)1.10Problem (18)2A New Hope202.1The Need For A Change (20)2.1.1Resolving The problem(s) (20)2.2The Hamiltonian Formulation (24)2.3Jacobi Action (26)2.4Conformally Related Solutions (27)2.4.1What ofξc? (28)2.5Topological Considerations (30)2.5.1Integral Inconsistencies(Slight Return) (30)2.5.2New Constraints (31)2.6The Hamiltonian Formulation (32)2.7The Volume (34)2.8Jacobi Action (34)2.9Comparison with GR (35)2.10Time (36)2.11Light Cones (37)2.12Matter in General Relativity (38)2.12.1Cosmological Constant (38)2.12.2Electromagnetism (39)2.12.3Dust (40)2.13Matter and Conformal Gravity (40)2.13.1Cosmological Constant (41)2.13.2Electromagnetism (41)2.13.3Dust (42)3Four Dimensions!443.1Introduction (44)3.2BOM Conformal Gravity (44)3.2.1The Action (45)3.2.2Dimensional Properties of Conformal Transformations (45)3.2.3Varying with respect to gαβ (46)3.2.4Varying with respect toφ (47)3.2.5A note on the action (47)3.2.6(3+1)-Decomposition (47)3.3Conformally Related Solutions (51)3.3.1Topological Considerations (51)3.4New Conformal Gravity (54)3.4.1Non-Compact (55)3.4.2Compact Manifold (56)3.5Special Case (61)3.6The Solar System (61)3.7Comment (62)4Cosmology634.1Introduction (63)4.2Cosmology In General Relativity (63)4.2.1Open Universe (63)4.2.2Flat Universe (64)4.2.3Closed Universe (64)4.3Cosmology in the Conformal Theory (66)4.3.1Open Universe (66)4.3.2Flat Universe (67)4.3.3The Closed Universe (68)4.4Cosmological Parameters (71)4.4.1Hubble Parameter (72)4.4.2Deceleration Parameter (72)4.5Problems of the Standard Cosmology (72)4.5.1The Cosmological Constant Problem (73)4.5.2The Flatness Problem (73)4.5.3The Horizon Problem (74)4.6Some Numbers (76)4.7A Non-Standard Cosmology:Anisotropy (78)4.7.1The Kasner Universe (78)4.7.2Effective Anisotropic Energy Density (79)4.8Discussion (80)5Discussion81Chapter1Introduction1.1IntroductionAs formulated by Einstein,the natural arena for gravity as represented by general rela-tivity(GR)is spacetime.We have a purely4-dimensional structure and the4-geometry reigns.(The invention of GR was a truly monumental achievement and no offence is intended by any attempt here to suggest an alternative theory.)Dirac[1]and Arnowitt, Deser and Misner(ADM)[2]reformulated the theory in canonical form which is more in-keeping with other areas of modern physics.This formulation led to Wheeler’s identi-fication of the configuration space as superspace and GR as the theory of the evolution of the3-geometry which led to the coining(again by Wheeler)of geometrodynamics.To get superspace onefirst considers Riem the space of all Riemannian3-geometries.Super-space is then Riem modulo diffeomorphisms,that is,we identify all3-geometries related by diffeomorphisms.York[3]went further and identified the conformal3-geometry with the dynamical degrees of freedom of the gravitationalfield.The correct configuration space for gravity should not be superspace but rather conformal superspace-superspace modulo conformal trans-formations.Barbour and´O Murchadha(BOM)[4]went further again and formulated a theory with conformal superspace at the very core.We’ll begin with a brief review of GR as found from the Einstein-Hilbert action and the ADM formulation.We’ll then discuss the York approach and the original BOM the-ory.All of this will serve as a warm up(albeit,a necessary warm up)to the real focus ofthis work.1.2General RelativityAlthough Einstein developed GR using beautiful physical reasoning and principles it is the Hilbert derivation from an action principle which is more instructive to us.(We will however refer to the action as the Einstein-Hilbert action as it was Einstein’s work which inspired Hilbert tofind the action to begin with.)The Einstein-Hilbert action of general relativity is well known.It has the formS=1−(4)g(4)R d4x(1.1)where gαβis the4-metric and(4)R is the four dimensional Ricci scalar.The action is varied with respect to gαβand the resulting equations are the(vacuum)Einstein equationsGαβ= Rαβ−1δgαβ(1.4) 1.3(3+1)-DecompositionBefore we consider the new theory it will be instructive to recall the ADM treatment of general relativity as much of this will carry straight over to the new theory.The idea in the ADM treatment is that a thin-sandwich4-geometry is constructed from two3-geometries separated by the proper time dτ.The4-metric found from the ADM construction is(4)g00(4)g0k(4)g i0(4)g ik=(N s N s−N2)N kN i g ik(1.5)N=N(t,x,y,z)is the lapse function given bydτ=N(t,x,y,z)dt(1.6) and N i=N i(t,x,y,z)are the shift functions given byx i2(x m)=x i1−N i(t,x,y,z)dt(1.7) where x i2is the position on the“later”hypersurface corresponding to the position x i1on the“earlier”hypersurface.The indices in the shift are raised and lowered by the3-metric g ij.The reciprocal4-metric is(4)g00(4)g0k(4)g i0(4)g ik=−1/N2N k/N2N i/N2g ik−N i N k/N2(1.8)The volume element has the formg dt d3x(1.9)This construction of the four metric also automatically determines the components of the unit timelike normal vector n−(4)g(4)R d4x(1.12) Using the Gauss-Codazzi relations we get(4)R=R−(trK)2+K ab Kab−2Aα;α(1.13) where Aαis given by(as earlier)Aα= nαtrK+aα (1.14)nαis the unit timelike normal andaα=nα;βnβ(1.15) is the four-acceleration of an observer travelling along nN.Substituting into the action givesS= N√2£n.In the coordinates we are using here the extrinsic curvature takes the formK ab=−1∂t−N a:b−N b;a(1.18)The action is varied with respect to∂g abg g ab trK−K ab (1.19) and varied with respect to N and N a to give the initial value equationsH=0and H a=0(1.20) respectively,whereH=√2(trπ)2 −√∂t =δH∂t =−δH1.4York’s ApproachThe Hamiltonian and momentum constraints correspond to the00and0a components of Einstein’s equations(1.3).They are equivalently initial-value constraints.We need to be able tofind initial data which satisfy these.One method was proposed by Baerlein, Sharp and Wheeler(BSW)[5].This is known as the thin-sandwich conjecture.First the pair{g ab,∂g ab√g ab trπ(1.31)3Now,if the CMC condition holds then the momentum constraint reduces to▽bσab=0(1.32)Now the tracefree part is transverse-traceless(TT).This property is invariant under the conformal transformationg ab−→ω4g ab(1.33)σab−→ω−4σab(1.34) It is important here that trπnow transforms in a different way to the tracefree partσab. For the momentum constraint to be conformally invariant we need to definetrp=trπg−→trp(1.35)That is,trp transforms as a conformal scalar.Since there is a well known method tofind a TT tensor we canfind the pair{g ab,σab}easily.The Hamiltonian constraint transforms to becomeσabσabφ−7−13trp(1.37) is often interpreted as a notion of time,the York time,due to the properties of trp noted above.1.4.1Gauge Fixing in GRIt is important to notice the difference between a single use of the CMC condition tofind initial data and subsequent use of the condition when the data is propagated.This is byno means guaranteed.As noted earlier,once the initial data has been specified the lapse and shift are freely specifiable.To maintain the CMC slicing during the evolution it is necessary to choose the lapse in a particular ing the evolution equations we get∂trp4+▽c trπg N c(1.38) To ensure CMC slicing we need to set▽c trπ=0and∂trp∂t =2NR−2▽2N+N(trp)2∂t=0.Thus∂trpg(R−(trK)2+K ab K ab)dtd3x(1.42)To find the conformal action we simply transform the Lagrangian under the transforma-tiong ab −→ψ4g ab(1.43)We need to define how the lapse and shift are transformed under such a transformation.In a later chapter we will see that this theory can be found using a 4-dimensional action whereg αβ−→ψ4g αβ(1.44)and under this we would haveN −→ψ2N(1.45)andN i −→ψ4N i(1.46)Let’s adopt these as our transformation rules.Under such a transformationR −→ψ−4R −8▽2ψ2N∂g ab∂t−→ψ4∂g ab∂t(KN )ab −→ψ4(KN )ab +4ψ3g ab N c ▽c ψ(1.50)ThusK ab −→ψ2B ab =−ψ2∂t−(KN )ab −θg ab(1.51)whereθ=−4∂t −N c ▽c ψ(1.52)The Lagrangian is thusL =N√ψ+B ab B ab −(trB )2(1.53)Noteψ ˙ψ−ψ,i N i .We can alsofind a coordinateindependent form for B.This isB=−1(ψ4g)(1.54)This is analogous to the expressionK=−1(g)(1.55)for the extrinsic curvature K in general relativity.1.5.2Constraints and Evolution EquationsWe can perform the usual variations tofind the constraints of the theory.Let’s vary with respect to Nfirst.This gives us,R−8▽2ψψ −▽2 Nψ3 =0(1.60)where we have used the other constraints to simplify.The constraints may appear more familiar if we write them in terms of the canonical momentum rather than B ab.Wefind the canonical momentum,πab by varying the action with respect to∂g abgψ4 g ab trB−B ab (1.61) Then using equation(1.58)we getπab=−√The constraints are then,πabπab−gψ8 R−8▽2ψψ −▽2 Nψ3 =0(1.66)Equation(1.63)corresponds to the Hamiltonian constraint of General Relativity.Equa-tion(1.64)is the usual momentum constraint of general relativity which represents diffeo-morphism invariance.Equation(1.65)is new and represents conformal invariance.Our initial data consists of a pair(g ab,πab)which must satisfy equations(1.64)and(1.65). These are the initial value equations.Equation(1.63)is used tofind the“conformal field”ψonce we have specified the initial data.Equation(1.66)is a lapse-fixing equation which is used to determine N throughout.We must check if these constraints are propa-gated under evolution.The evolution equations are found in the usual way.They are∂g ab2ψ−4πab+(KN)ab−θg ab(1.67) and∂πabgNψ4 R ab−g ab R−8▽2ψ2ψ−4πacπb c+√gψ3 ▽a▽bψ+3g ab▽2ψ+4√g▽(a(Nψ3)▽b)ψ+▽c N cπab −πbc▽c N a−πac▽c N b−θπab (1.68)It can be verified that these equations do indeed preserve the constraints.We can see how similar the results are to those in York’s approach.The Hamiltonian constraint has become the Lichnerowicz equation.The momentum is TT.Also,the lapsefixing equation is the gauge requirement of GR to preserve the trπ=0constraint.Of course,those equations are all secondary in GR whereas here they have arisen directly through a variational procedure!1.5.3The HamiltonianNow that we have found the momentum it is straightforward to find the Hamiltonian.As usual we haveH =πab∂g abgψ4R −8▽2ψ2(trπ)2√2(trπ)2−√ψ−2N a ▽b πab +θtrπd 3x(1.71)Recalling the constraints we see that yet again,as found by Dirac and ADM,the Hamil-tonian is a sum of the constraints with Lagrange multipliers.1.6Jacobi ActionBaerlein,Sharp and Wheeler [5]constructed a Jacobi Action for general relativity.Their action was,S =+g√T GR d 3x(1.72)whereT GR =g ac g bd −g ab g cd∂g ab∂t−(KN )cd(1.73)Variation with respect to∂g abgR∂t−(KN )cd(1.74)This expression is squared to give the Hamiltonian constraint.The variation with respect to N a gives the momentum constraint.The evolution equations are found in the usual way.The equations found with the Jacobi action are those of general relativity if we identify 2N and R .We want to construct the analogous case in conformal gravity.Letus return to our (3+1)Lagrangian,L =N√ψ−(trB )2+B ab B ab(1.75)We can write this asL =√ψ+1∂t−(KN )ab −θg ab.We now extremise with respect to N .This gives us,N =+2βab βab −(trβ)21ψ −1dλ √R −8▽2ψT d 3x(1.78)where T =βab βab −(trβ)2 .This is the conformal gravity version of the BSW action (1.72).We can do all the usual variations here:N a ,˙ψand ψ.These give the momentum constraint,the conformal constraint and the lapse-fixing equation respectively.Becauseof the independent variations of ˙ψand ψ,it turns out that we may vary with respect to θand ψto get the conformal constraint and the lapse-fixing equation respectively.When we find the canonical momentum πab we can “square”it to give the “Hamiltonian constraint.”Actually,this is precisely the BOM action found by starting with the BSW action and conformalising it under conformal transformations of the 3-metricg ab −→ψ4g ab(1.79)The Jacobi action is manifestly 3-dimensional and its configuration space is naturally conformal superspace -the space of all 3-D Riemannian metrics modulo diffeomorphisms and conformal rescalings.1.7Conformally Related SolutionsIn conformal superspace conformally related metrics are equivalent.Thus conformally related solutions of the theory must be physically equivalent and so it is crucial that we have a natural way to relate such solutions.Suppose we have one set of initial data (g ab ,πab ).These must satisfy the constraints (1.64)and (1.65).We solve the Hamiltonian constraint (1.63)for our “conformal field”ψ.Suppose now we start with a different pair (h ab ,p ab )where h ab =α4g ab and ρab =α−4πab .Our new initial data is conformallyrelated to the original set of initial data.This is allowed as“transverse-traceless”-ness is conformally invariant and so our initial data constraints are satisfied.All we must do is solve the new Hamiltonian constraint for our new conformalfieldχsay.This constraint is nowρabρab=hχ8 R h−8▽2hχ.That is,ψis automati-αcally transformed when our initial data is transformed.Now,ψ4χ4h ab==Ng−1∂t=−√gN∂t−√2πacπb c−▽c N aπbc−▽c N bπac+▽c N cπab (1.88)These are exactly those of general relativity on a maximal slice.Thus,solutions of general relativity in maximal slicing gauge are also solutions here.There are of course solutions of general relativity which do not have a maximal slicing and these are not solutions of the conformal theory.1.8Topological ConsiderationsSo far we have not considered any implications which the topology of the manifold may have.In an asymptoticallyflat case we have no problems with the theory as it stands. This is not the case however in a topology which is compact without boundary.1.8.1Integral InconsistenciesRecall the lapse-fixing equation of the theory in the physical representation(removing the “hats”for simplicity),NR−▽2N=0(1.89) Let’s integrate this equation:√g▽2N d3x=0(1.90)The second term integrates to zero and so we just have√gNR d3x− √gNR d3x(1.93) is positive definite.The second integral is− √gN▽c N dΣc(1.95)whereΣc is the boundary on which N=0.Since N is decreasing on the boundary we have that this term is positive definite.This means however that we have a vanishing sum of two positive definite quantities.This is a contradiction.Thus we must have N≡0. We get frozen dynamics.(This is not the case with a manifold which is asymptotically flat so the earlier analysis works in that case.)Frozen dynamics also arises in general relativity if one imposes afixed trπ=0gauge condition.However,this is a problem of the gauge rather than a problem of the theory as with conformal gravity.(See[6]for a treatment of this problem.)The easiest way to resolve this problem involves a slight change to the action.We intro-duce a volume term.The inspiration for this term comes from the Yamabe theorem.The action isS= N√V2/3 R−8▽2ψgψ6d3x(1.97) The power of2gψ4V4/3 R−8▽2ψψ −▽2 Nψ3 =Cψ5(1.102)The term C is given byC= N√V R−8▽2ψV(ψ)4/3(1.104)▽bπab=0(1.105) trπ=0(1.106) NR−▽2N=C(1.107)where C is nowC=1g√T: A is the average of A given by the usual notion of averageA = √ √gNR d3x− ▽2N d3x− √gNR d3x− √:Although we have only used the physical representation in our integral tests it can be verified easily that everything also works out in the general representation.Of course,in EVERY situation,this must be true.We are losing nothing by working in the physical representation.We should consider the evolution equations again now that we have changed the action. The evolution equations become∂g ab2V(ψ)2∂t =−N√V2/3 R ab−g abR−8▽2ψ√gψgψ3gg ab g3√V2/3(1.114)where C is as in(1.103).As usual we can write these in the physical representation.In this form the evolution equations are∂g ab2V2∂t =−N√V2/3 R ab−g ab R−2NV4/3gπacπb c +√V2/3 ▽a▽b N−g ab▽2N+▽c N cπab −πbc▽c N a−πac▽c N b−2gg ab CThe lapse-fixing equation isNR−▽2N=C(1.121) These are precisely the constraints and gaugefixing conditions for propagated maximal slicing in GR.The evolution equations are∂g ab2 πab+(KN)ab(1.122) and∂ πab g R ab−g ab R −2N g πac πb c+√3√V2/3(1.123)which are identical to those in GR apart from the global C term in the equation forπab. We can easilyfind the Hamiltonian and the Jacobi action for the new form.They are H= N V2/3gψ4 πabπab−1gψ4ψ d3x(1.124) andS= dλ √R−8▽2ψT3d3x(1.125) Note again the homogeneity throughout inψ.1.9Other ResultsThere has been work on other aspects of this theory not described here.It is unnecessary from the point of view of this work while,of course,being valuable in itself with a number of worthwhile results most notably on the constraint algebra and the Hamilton-Jacobi theory.The interested reader canfind this in[7].1.10ProblemAlthough the theory has emerged beautifully and easily form very natural principles we canfind at least one major problem immediately.Consider the volume of a hypersurface VV= √Taking the time derivative of this we get∂V2√∂td3x(1.127)This becomes∂V∂t=0(1.129) and the volume of the universe is static.This rules out expansion and thus the stan-dard cosmological solution is lost.In particular,the red-shift,an experimental fact,is unexplained.This is a serious shortcoming.All is not lost however...Chapter2A New Hope2.1The Need For A ChangeDespite all the promising features of the theory there is at least one major drawback.We canfind the time derivative of the volume quite easily and get that it is proportional to trπand thus is zero.That is,the volume does not change and so the theory predicts a static universe and we cannot have expansion.This is quite a serious problem as the pre-diction of expansion in GR is considered to be one of the theory’s greatest achievements. We are left with the following options:(a)Abandon the theory;(b)Find a new explanation of the red-shift(among other things);(c)Amend the theory to recover expansion.Thefirst option seems quite drastic and the second,while certainly the most dramatic, also seems to be the most difficult.Thus,let’s check what we canfind behind door(c).2.1.1Resolving The problem(s)Any change to the theory needs to be made at the level of the Lagrangian and so we’ll return to our earlier expression for LL=N√ψ+B ab B ab−(trB)2 (2.1)but naively change the form of B ab toB ab=−1∂t−(KN)ab−▽cξc g ab(2.2)Let’s vary the action with respect toξc.We getδL=N√gψ4 B ab−2trBg ab −1gψ4trB▽cδξc(2.3)Integrating by parts givesδL=2√3g ab trB(2.8) We shall retain the new form of B ab as defined above in(2.2)all the same.The Lagrangian now readsL=N√ψ+S ab S ab−2gψ4 R−8▽2ψ3ψn(trB)2 (2.10)Before we continue,one interesting point about S ab is the following.We haveS ab =B ab −12N∂g ab3g abg cd ∂g cd2N∂g ab2Ng ab ▽c ξc −1∂t−g cd (KN )cd−32N∂g ab3g abg cd∂g cd3g ab trK (2.15)That is,S abis the tracefree part of the extrinsic curvature and is independent of anyconformal fields.Let us find πab .This is done as usual by varying with respect to∂g abgψ42S ab δS ab −4gψ4S ab δB ab −13ψn trBg ab δB ab=2N√3ψn trBg abδB ab=−√3ψn S ab trBδ∂g abgψ4S ab +2gψn +4g ab trB(2.17)Splitting πab into its trace and tracefree parts will further clear things up.We’ll label the split asπab =σab +1gψ4S ab (2.19)and the trace is given bytrπ=2ψn+4trB(2.20) Note that our value of n is undefined as yet.The constraints are found by varying with respect toξc,ψ,N and N a.The confor-mal constraint and the lapse-fixing equation are given by varying with respect toξc and ψrespectively.These give▽c trπ=0(2.21) andNψ3 R−7▽2ψ4=0(2.22) respectively.From the variation with respect to N we getS ab S ab−2ψ =0(2.23) which in terms of the momentum isσabσab−1ψ =0(2.24) andfinally,from the variation with respect to N a we get▽bπab=0(2.25) We require conformal invariance in our constraints.Under what conditions is the momen-tum constraint(2.25)invariant?The tracefree part of the momentum,σab,has a natural weight of−4(from the original theory).That isσab−→ω−4σab(2.26) If trπ=0then we have conformal invariance.If not however,we require various further conditions.We need▽bσab=0(2.27)▽c trπ=0(2.28)and thattrp=trπg−→trp(2.29)under a conformal transformation.In our theory we have thefirst two conditions emerg-ing directly and naturally from the variation.Thus we simply define trp to transform as a conformal scalar as required.With this done our momentum constraint is conformally invariant.23Transforming the constraint(2.24)givesσabσab−1ψ =0(2.30) and so we must have n=−12for conformal invariance.The constraint then becomesσabσab−1ψ =0(2.31)(Note:This is exactly the Lichnerowicz equation from GR.However,we have found it directly from a variational procedure.)Thus we have determined the unique value of n and our constraints areσabσab−1ψ =0(2.32)▽bπab=0(2.33)▽c trπ=0(2.34) Nψ3 R−7▽2ψ4=0(2.35) Let’s proceed to the Hamiltonian formulation.2.2The Hamiltonian FormulationThe earlier expression forπab can be inverted to get∂g ab∂t =2Ngψ4 σab−1√6(trπ)2ψ12−gψ8 R−8▽2ψAs a consistency check let’sfind∂g ab∂t =2Ngψ4 σab−1∂t=−N√ψ−2N gψ4 πacπb c−16πab trπψ12+√gψ3 ▽a▽bψ+3g ab▽2ψ+4g ab√g▽(a(Nψ3)▽b)ψ+▽c πab N c −πbc▽c N a−πac▽c N b− πab−1∂tquite easily.(Of course,we need the evolution equations to propagate all of the constraints.We will deal with the others later.)Wefind that∂trp∂t =∂πab3∂g ab trπWorking through the details gives us∂σabgψ4 R ab−1ψ −2N gψ4σacσb c+√3g ab▽2(Nψ3)+N√3g ab▽2ψ(2.42)+4g ab√g▽(a(Nψ3)▽b)ψ+▽c σab N c −σbc▽c N a−σac▽c N b−σab▽cξc+Nψ8gσab trπ2.3Jacobi ActionWe can alsofind the Jacobi action of this theory.Recall the(3+1)Lagrangian,L=N√ψ+S ab S ab−2gψ4 N R−8▽2ψ4N ΣabΣab−21ψ−12(trβ)2 1ψ −13dλ √R−8▽2ψT d3x(2.46) where T= ΣabΣab−22.4Conformally Related SolutionsWe can do almost exactly the same thing here as we did in the section with the same name in Chapter1.Suppose we start with initial data{g ab,σab,trp}obeying the initial data conditions(2.33)and(2.34).We then solve(2.32)forψSuppose instead that we start with the conformally related initial data{h ab,ρab,trp}= {α4g ab,α−4σab,trp}.These automatically satisfy the initial data conditions by the con-formal invariance.We now solve the Hamiltonian constraint for the conformal“field”χ, say.Just like before it can be shown thatχ=ψ6(trπ)2− g R=0(2.49)▽b πab=0(2.50)▽c trπ=0(2.51)N R− ▽2 N+( trp)26(trπ)2−gR=0(2.53)▽bπab=0(2.54)▽c trπ=0(2.55) Evolution of the CMC condition givesNR−▽2N+(trp)22.4.1What ofξc?Precious little has been revealed about whatξc may be or even how it transforms.This needs to be addressed.First let’s recall that we demanded thattrB−→ω−8trB(2.57)under a conformal transformation.This will be enough to reveal the transformation properties ofξc.Taking the trace gives ustrB=−1∂t−g ab(KN)ab−3▽cξc(2.58)Under a conformal transformation we getω−8trB=−1∂t+12˙ω2ω2N g ab∂g ab2ω2N▽cξc+3ω3N ˙ω−ω,c N c=ω−2trB+3ω ˙ω−ω,c N c(2.59)Thus,3ω ˙ω−ω,c N c=−1ω ˙ω−ω,c N c−2N∂t =2 N g σab−1and∂ σab g R ab−1g ▽a ▽b N−13ω(˙ψ−ψ,c N c)−2Nψ(˙ψ−ψ,c N c)+2N3trB(1−ψ−6)(2.66)whereθis as in the original theory.Thus,the exact form ofξc is determined.We needed ▽cξc to be zero in the physical representation for constraint propagation and so we should check that this is the case with our newly found expression for▽cξc.We can check this easily.In the physical representationθ=0andψ=1.Thus,we do have that ▽c ξc is zero.It is vital to note that this is strictly a POST-VARIATION identification.If we use this form forξc in the action we will run into problems,not least an infinite sequence in the variation of trB with respect toξc.(This is because we would have trB defined in terms of trB itself.)We see thatξc is intimately related with howψchanges from slice to slice.Our constraints in the physical representation areσabσab−1。
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Coullet system is proposed. In Section Ⅴ , numerical simulations are presented to demonstrate the effectiveness of the proposed method. Finally, conclusions are given in Section Ⅵ. II. IONAL ORDER
d q X1 = F(X1) , dt q
Where
(3)
X 1 ∈ ℜ n×1 , F ( X 1 ) = ( f ( x1 ), f ( x 2 ),..., f ( x n )) T
n×1
and
may be 0 < q ≤ 1 . The fractional order q ∈ ℜ unequal. The equilibrium points of system (3) can be derived by solving following equation F(X1) = 0 , (4) The stability of fractional order system has been thoroughly investigated, and necessary and sufficient conditions have been presented in Ref.[13]. Let the corresponding response(slave) system be
A note on synchronization of a fractional order Coullet chaotic system
Wen Tan 1, 2 ,Fengling Jiang 2 , Jian Xun Liu 1 ,Min Chen 2
1. Key Lab of Knowledge Processing and Networked Manufacture, Hunan University of Science and Technology, Xiangtan, Hunan, 411201,China 2. College of Information & Electrical Engineering, Hunan university of Science and Technology, Xiangtan,Hunan,411201,China wentan168@
(2)
α
Here Γ denotes Gamma function and the operator D* is called Caputo differential operator of order α . Given a fractional order chaotic system, i.e., the drive(master) system is
SYSTEM’S SYNCHRONIZATION THEORY
At present, there are many definitions of the fractional derivatives[9,10], in the paper, the following definition is used
dqX2 (5) = F ( X 2 ) + u (t ) , dt q n×1 where X 2 ∈ ℜ , u (t ) is control function. Suppose the
error between the system (3) and the system (5) is
e(t ) = X 1 (t ) − X 2 (t ) , then the fractional error system
less than α . J ( β > 0) is the β -order Riemann-Liouville integer operator which satisfies
β
J β y (t ) =
β −1 t 1 ( t − τ ) y (τ ) d τ , β > 0 , Γ ( β ) ∫0
can be obtained as
order 0 < q ≤ 1 is asymptotically stable corresponding integer order system (8) is stable.
if
the
d qe = F ( X 1 ) − F ( X 2 ) − u (t ) , dt q
α D* x(t ) = J m −α x ( m) (t ) , (α > 0) , (1) Where m = [α ] ,i.e., m is the first integer which is not
I.
INTRODUCTION
The fractional differential calculus dates from 17th century, but until recent 10 years that it was applied to physics and engineering[1,2]. It was found that many systems in interdisciplinary fields could be described by the fractional differential equations, such as viscoelastic systems,dielectric polarization, electrode-electrolyte polarization and electromagnetic waves[1]. Nowadays, it was known that the fractional order systems possess memery and display much more sophisticated dynamics compared to its integral order counterpart, which is of great significance in secure communication and control process. Furthermore, many fractional order dynamical systems have been examined to exhibit chaotic behavior[3]. Recently, Chaos synchronization problem of fractional order differential systems are being widely investigated[4-7], for different chaotic systems, various relevant control methods are used to deal with them. So far, there is only a report on control and synchronization of a fractional order Coullet chaotic system[8]. Unfortunately, the numerical simulation results presented in the above paper are not consistent with reality.Accordingly,This paper focuses on synchronization of two fractional order Coullet chaotic systems. In virtue of the Lyapunov stability theory, suitable conditions for nonlinear feedback control are derived and further verified through simulations. The rest of the paper is organized as follows. In Section Ⅱ , fractional differential and fractional order system’s synchronization theory are introduced. In Section Ⅲ, the fractional order Coullet system is described. In Section Ⅳ, the nonlinear feedback synchronization of fractional order