New experimental limit on the Pauli Exclusion Principle violation by electrons
Chemistry Chapter 5
Chemistry Chapter 5 WS #1 (first four pages)Complete the worksheet while viewing the power point. Use your textbook to answer remaining questions after the power point. Some information repeats itself. Consider this the important concepts in the chapter.Name of chapter:5.1 The Development of Atomic Models1. Rutherford’s atomic model could not explaina. why _________________________________give off characteristic colors when heatedb. why objects ___________________________ first glow dull red, then yellow, then white.c. his model could not explain ____________________________________.The Bohr Model2. Bohr proposed that an electron is found only in specific circular paths, or _________, aroundthe nucleus.3. Each possible electron orbit in Bohr’s model has a fixed energy called ____________.4. A quantum of energy is the amount of energy required to move an electron_______________________________________________________________________.The Quantum Mechanical Model5. Erwin Shrodinger used math to propose the ___________________________ model.6. The quantum mechanical model determines the allowed energies an electron can have and how likely it is ___________________________________________________________________________________________________________________________.Atomic Orbitals7. An _______________________ is often thought of as a region of space in which there is a high probability of finding an electron. The s orbitals are _____________ shaped, and p orbitals are __________________ shaped.5.2 Electron Configurations8. The ways in which electrons are arranged in various orbitals around the nuclei of atoms are called ________________________.9. Aufbau principle: electrons occupy the orbitals of _________ energy first.Pauli exclusion principle: an atomic orbital may describe at most ____________. To occupy the same orbital, two electrons must have ______________; that is, the electron spins must be paired. Hund’s rule: electrons occupy orbitals of the ______________ in a way that makes the number of electrons with the _____________ direction as large as possible.Some actual electron configurations differ from those assigned using the aufbau principle because __________sublevels are not as stable as _________ sublevels, but they are more stable than other configurations.Exceptions to the aufbau principle are due to ___________________________________ in orbitals with very similar energies.5.3 Physics and the Quantum Mechanical Model—Light10. The __________________ of a wave is the wave’s height from zero to the crest. The______________________, represented by _________, is the distance between the crests. The _________________, represented by _______, is the number of wave cycles to pass a given point per unit of time. The SI unit for cycles per second is the ___________. The speed of light is _________________. Draw a picture of a wave and label the parts.11. ___________________________________ include radio waves, microwaves, infrared waves, visible light, ultraviolet waves, X-rays, and gamma rays.12. When sunlight passes through a prism, the different frequencies separate into a______________ of colors. The lowest frequency and longest wavelength is _____________. The other colors in order are _____________________________________________________. Atomic Spectra and Explanation of Atomic Spectra13. When atoms absorb energy, __________ move into higher energy levels. These electrons then lose energy by ________________ when they return to lower energy levels.14. The frequencies of light emitted by an element separate into discrete lines to give the_____________________ of the element.15. When the electron has its lowest possible energy, the atom is in its _______________.16. Excitation of the electron by absorbing energy raises the atom from the ground state to an______________.17. A quantum of energy in the form of light (photon) is emitted when the electron drops back toa ___________________.18. The light emitted by an electron moving from a higher to a lower energy level has a frequency __________ proportional to the energy change of the electron.Quantum Mechanics19. Einstein proposed that light could be described as quanta of energy called ______________. The quanta behave as if they were ____________________, resulting in a dual wave-particle behavior.20. In 1924, De Broglie developed an equation that predicts that all moving objects have___________________ behavior.21. The older theory of classical mechanics, adequately describes __________________________________________________________, while the newer theory of quantum mechanics describes ___________________________________________________________________. 22. The ___________________ uncertainty principle states that it is impossible to know exactly both the velocity and the position of a particle at the same time. The very act of measuring the position of an electron changes it velocity, and makes its velocity uncertain.Review…5.2 Electron Configurations (pages 133–135)1. The ways in which electrons are arranged around the nuclei of atoms arecalled ___________________________________________ .2. In the shorthand method for writing an electron configuration, what does asuperscript stand for? What do the sum of the superscripts equal?5.3 Light (pages 138–140)1. Match each term describing waves to its definition._______ amplitude a. the distance between two crests_______ wavelength b. the wave’s height from the origin to the crest_______ frequency c. the number of wave cycles to pass a given point per unit of time Atomic Spectra (page 141)4. What happens when an electric current is passed through the gas or vapor ofan element?5. Is the following sentence true or false? Explain. The emission spectrum of an elementcan be the same as the emission spectrum of another element.An Explanation of Atomic Spectra (pages 142–143)6. What is the lowest possible energy of an electron called?7. Only electrons moving from ______________________ to______________________ energy levels lose energy and emit light.WS #2 (last two pages)Chemistry—Ch. 5 textbook problems p. 149-151 (22-26, 30, 34-35, 40, 43, 61-65, 68)22. What was inadequate about Rutherford’s model of the atom? Which subatomic particles didThomson include in the plum-pudding model of the atom?23. What did Bohr assume about the motion of electrons?24. Describe Rutherford’s model of the atom and compare it with the model proposed by hisstudent Niels Bohr.25. What is the significance of the boundary of an electron cloud?26. What is an atomic orbital?30. How many electrons are in the highest occupied energy level of these atoms?c)barium b) sodium c) aluminum d) oxygen34. Give electron configurations for atoms of these elements:a) Na b) S c) Mgd) Ne e) K35. Which of these orbital designations are invalid?a)4s b) 2d c) 3f d) 3d40. List the colors of the visible spectrum in order of increasing wavelength.43. Explain the difference between the energy lost or gained by an atom according to the laws ofclassical physics and according to the quantum model of an atom.61. Pieces of energy are known asa) isotopes b) particles c) quanta d) line spectra62. The lowest sublevel in each principal energy level is represented by the symbola) f b) p c) s d) d63. Which electron transition results in the emission of energy?a)3p to 3s b) 3p to 4p c) 2s to 2p d) 1s to 2s64. Which is the ground state configuration of a magnesium atom?a) 1s22s22p63s2b) 1s22s22p63s1 c) 1s22s23s22p6 d) 1s22s22p43s265. Explain the difference between an orbit in the Bohr model and an orbital in the quantum mechanical model of the atom.68. Orbital diagrams for the ground states of two elements are shown below. Each diagramshows something that is incorrect. Identify the error in each diagram and then draw thecorrect diagram.a. Nitrogenb. MagnesiumCh. 4 review questions_______________ discovered the electron in 1897. He sealed gases in a tube and put electricity through the tube. The result was a glowing beam, or________________ ray. By using a magnet, he showed that there were tiny_______________ charged particles moving at high speeds (corpuscles or electrons). He found that the charge-to-mass ratio of electrons did not depend on the kind of gas used or type of metal plates. Thus, electrons must be part of the atoms of all elements.Thomson’s ___________________ model suggested that atoms were a_______________ mass with _______________ charged particles within similarto a plum pudding. His student, ___________________, disproved this theory by his ____________________ experiment. He found that most alpha particles went straight through showing that an atom is mostly _______________ space. He also concluded that there is a small, dense, positively charged _______________ at the center of the atom.Ch. 5 concept questionOuter _______________ gain a quantum of energy from high temperature or high _______________ and move from the ground state to an excited state. The_______________ are not stable in this higher energy level, so they emit energy called _______________ and move back to the lower energy, or ground state. We see colors because the energy emitted is in our _______________ spectrum, which is between ________ nm and __________nm. The colors in this spectrum from lowest energy are _________________________________________________________________________________________________________________.。
英语同等学力人员申请硕士学位试卷及答案指导(2025年)
2025年同等学力人员申请硕士学位英语自测试卷及答案指导一、口语交际（共10分）第一题Conversation:A: Hi Jacob, how are you?B: Hi Anna, I’m doing pretty well, thanks. How about you?A: I’m doing great. I was just thinking about the upcoming group project. We need to split the work.B: Sure, no problem. What tasks do you think we should work on?A: Well, I was considering the research part since I have experience in that area.B: That sounds fair. I’ll take care of the writing part then. Let’s set up a meeting to discuss the specifics later.A: Definitely. I’ll send out the meeting invite next week.1、What is the purpose of their conversation?a)Planning a meetingb)Discussing the division of laborc)Complaining about the workloadd)Introducing new members to the teame)Sharing personal health updatesAnswer: b2、Whom is Anna talking to?a)Her family memberb)Her colleaguec)Her friendd)Her professore)Her clientAnswer: b3、What task is Anna considering for herself?a)Writingb)Presentingc)Researchd)Editinge)DesigningAnswer: c4、What task is Jacob taking care of?a)Researchb)Writingc)Presentationd)Editinge)DesigningAnswer: b5、What will Anna do after the conversation?a)Call Jacobb)Send out a meeting invitec)Finish the project aloned)Cancel the projecte)Ask for more tasksAnswer: b第二题A conversation between two friends, Alice and Bob, about their study plans and university life.Alice: Hi, Bob! It’s been a while since we last studied together. Are you still preparing for the postgraduate entrance exam?Bob: Hi, Alice! Yes, I am. I’m really excited to enter graduate school. How about you? Have you made any progress on your studies?Alice: Yes, I’ve been working hard. I’m particularly focused on preparing for the TOEFL exam as it’s a requirement for my pro gram. Last week, I attended a preparation class and I wanted to discuss it with you.Bob: That’s great! What do you think of the class?Alice: I found it quite helpful. The instructor explained the format and strategies for each section. We even had a little practice session at the end.Bob: Nice! I heard about the class. Do you think it covered everything important?Alice: Yeah, I think it did. They even provided some sample questions andanswered our doubts. I was able to improve my speaking skills, which is essential for my program.Bob: Speaking skills are indeed crucial. By the way, is there anything you want to improve the most?Alice: Definitely my writing. It’s really challenging for me. I struggle to organize my thoughts and write coherently. So, any tips you can give me would be appreciated.Bob: Sure, I can help with that. First, try to practice writing short essays on a regular basis. It’ll help you get used to the structure and vocabulary required for academic writing.1.What topic did Alice discuss with Bob about her study plan?A) The postgraduate entrance examB) The TOEFL examC) The preparation class for the postgraduate entrance examD) The challenges she faces in her writing2.How does Alice feel about the preparation class she attended?A) She thinks it’s a waste of time.B) She thinks it’s quite helpful.C) She thinks it’s not informative enough.D) She thinks it’s too difficult for her.3.What kind of assistance does Alice seek regarding her writing improvement?A) Reading tipsB) Speaking tipsC) Writing tipsD) Vocabulary tips4.What does Bob suggest Alice do to improve her writing?A) Practice reading a lotB) Practice writing short essays regularlyC) Focus solely on spoken EnglishD) Take a proofreading course5.What is one aspect of the TOEFL exam that Alice needs to improve on?A) Listening skillsB) Reading skillsC) Writing skillsD) All of the aboveAnswers:1.B2.B3.C4.B5.C二、词汇-选择填空（本大题有10小题，每小题1分，共10分）1、In today’s fast-paced world, staying healthy requires a__________balance of physical exercise, a nutritious diet, and mental well-being.A. perfectB. perfectibleC. perfectiveD. perfectible答案：A解析：选项A “perfect” 意为“完美的”，符合题意。
超实用备战高考英语考试易错题——阅读理解：主旨大意题(大陷阱) (解析版)
易错点17 阅读理解主旨大意题目录01 易错陷阱（3大陷阱）02 举一反三【易错点提醒一】标题类易混易错点【易错点提醒二】段落大意类易混易错点【易错点提醒三】文章大意类易混易错点03 易错题通关养成良好的答题习惯，是决定高考英语成败的决定性因素之一。
做题前，要认真阅读题目要求、题干和选项，并对答案内容作出合理预测;答题时，切忌跟着感觉走，最好按照题目序号来做，不会的或存在疑问的，要做好标记，要善于发现，找到题目的题眼所在，规范答题，书写工整;答题完毕时，要认真检查，查漏补缺，纠正错误。
易错陷阱1：标题类易混易错点。
【分析】标题类是对中心思想的加工和提炼，可以是单词、短语、也可以是句子。
她的特点是短小精悍，多为短语；涵盖性、精确性强；不能随意改变语言表达的程度和色彩。
如果是短语类选项，考生容易混淆重点，此时应当先划出选项的关键词。
此类题和文章的中心主题句有很大关系。
中心主题句一般出现在第一段，有时第一段也可能引出话题，此时应当重点关注第二段和最后一段，看看是否会出现首尾呼应。
易错陷阱2：段落大意类易混易错点。
【分析】每个段落都有一个中心思想，通常会在段落的第一句或最后一句体现，这就是段落主题句。
如果没有明显的主题句时，应当根据段落内容概括处段落大意。
有时考生还会找错文章对应位置，盲目选词文中相同的词句，而出现文不对题的现象。
易错陷阱3：文章大意类易混易错点。
【分析】确定文章主旨的方法是：先看首尾段或各段开头再看全文找主题句，若无明显主题句，就通过关键词句来概括。
如，议论文中寻找表达作者观点态度的词语，记叙文中寻找概括情节和中心的动词或反映人物特点的形容词。
文中出现不同观点时，要牢记作者的观点彩色体现全文中心的。
此时，要注意转折词，如：but, however, yet, in spite of, on the contrary等。
【易错点提醒一】标题类易混易错点【例1】（浙江省义乌五校2023-2024学年高三联考试题）The scientist’s job is to figure out how the world works, to “torture (拷问)” Nature to reveal her secrets, as the 17th century philosopher Francis Bacon described it. But who are these people in the lab coats (or sports jackets, or T-shirts and jeans) and how do they work? It turns out that there is a good deal of mystery surrounding the mystery-solvers.“One of the greatest mysteries is the question of what it is about human beings — brains, education, culture etc. that makes them capable of doing science at all,” said Colin Allen, a cognitive scientist at Indiana University.Two vital ingredients seem to be necessary to make a scientist: the curiosity to seek out mysteries and the creativity to solve them. “Scientists exhibit a heightened level of curiosity,” reads a 2007 report on scientific creativity. “They go further and deeper into basic questions showing a passion for knowledge for its own sake.” Max Planck, one of the fathers of quantum physics, once said, the scientist “must have a vivid and intuitive imagination, for new ideas are not generated by deduction (推论), but by an artistically creative imagination.”......ong as our best technology for seeing inside the brain requires subjects to lie nearly motionless while surrounded by a giant magnet, we’re only going to make limited pro gress on these questions,” Allen said.What is a suitable title for the text?A．Who Are The Mystery-solversB．Scientists Are Not Born But MadeC．Great Mystery: What Makes A ScientistD．Solving Mysteries: Inside A Scientist's Mind【答案】C【解析】文章标题。
数字时代音乐家保护自己权利
control of media by newspapers and reporting); Kimberlianne Podlas, Respect My Authority!. South Park's Expression Of Legal Ideology and Contribution To Legal Culture, 11 VAND. J. ENT. & TECH. L. 491, 500-01 (2009) [hereinafter Podlas, South Park]; Sotirovic, supra note 6, at 133-34. See generally Fuyuan Shen, Chronic Accessibility and Individual Cognitions: Examining the Effects of Message Frames in PoliticalAdvertisements, 54 J. Comm. 123 (2004). 9 Jodi Baumgartner, The Daily Show Effect: Candidate Evaluations, Efficacy, and American Youth, 34 AM. POL. RES. 341, 341-43 (2006); Young Mie Kim & John Vishak, Just Laugh! You Don't Need To Remember, 58 J. COMM. 338, 338-42 (2008); see also Stuart Levine, Peabody Awards Announce Winners, DAILY VARIETY, Apr. 1, 2009, /article/VR1118001974.html? categoryid=1985&cs=1 (showing the impact of Saturday Night Live's political parodies on the 2004 election").
奥本海默简介英语作文
奥本海默简介英语作文Oppenheimer (J. Robert Oppenheimer, 1904-1967) , American physicist and “Father of the atomic bomb”.Oppenheimer was born in 1904 to a wealthy German-jewish family in New York. In 1921, Oppenheimer graduated summa cum laude from the New York School of Ethics and culture. He became ill and was admitted to Harvard's chemistry department the following year, he took a course in advanced thermodynamics taught by renowned experimental physicist Bridgman, which first interested him in physics -- a science that touched on his “Atomic complex.”, so he threw himself into a research project led by Bridgman and decided to apply for the Cavendish Cavendish Laboratory at the University of Cambridge after graduation.In 1925, Oppenheimer graduated summa cum laude from Harvard ahead of schedule and was recommended to the Trinity College by Bridgman. He then moved to the University of Göttingen, Germany, where he studied under M. Max Born worked with Max Born on a paper called “Quantum theory of molecules,” which laid the foundation for the study of molecular spectroscopy and established the molecular canon, he received his phd in 1927 under the direction of Max Born.In the summer of 1927, Oppenheimer returned home, first to Harvard, then to University of California, Berkeley and the California Institute of Technology in Pasadena. Between 1928 and 1929 he went toEurope, at Leiden University and the University of Zurich, with Alan Feist and W. Wolfgang Pauli, whose work has been influenced by Wolfgang Pauli, has always been at the forefront of the development of physics. He predicted the existence of positrons as early as 1930, and in 1931 showed that particles with different spins, integers and half-integers, had different theoretical structures, the nature of these elementary particle was described, calculated and explained in conjunction with numerous observations of cosmic ray and nuclear physics at the time, he has established himself as a leader in American physics.At the same time, Oppenheimer also gradually demonstrated his potential as a good teacher and quality. Always surrounded by a group of talented and sharp-minded young men, Burkley gradually became the center of American theoretical physics, most of the young physicists he trained later became the top experts in the field of physics and formed the famous school of Theoretical Physics in American physics.In 1942, a turning point in Oppenheimer's life, he was appointed director of war Los Alamos National Laboratory and Technical Director of the Manhattan Project, which built the atomic bomb.Oppenheimer returned to the University of California and the Polytechnic shortly after the war, Institute for Advanced Study in 1947 and became president of the American Physical Society the following year. From 1945 to 1953, Oppenheimer became one of theadministration and Congress' leading advisers on atomic energy policy, including two terms as chairman of the General Advisory Committee of the Government's Atomic Energy Commission. With deep awareness and guilt over the dangers of the atomic bomb, with foresight and fear of a Nuclear arms race between the United States and the Soviet Union, with a conscience that upholds fundamental human values and a sense of social responsibility responsible for the future, fully committed to the international control and peaceful use of atomic energy through the United Nations, and advocating the exchange of nuclear scientific information with all major powers, including the former Soviet Union, in order to reach relevant agreements, and opposed the US taking the lead in building a hydrogen bomb. However, Oppenheimer's political ideas and experience were clearly naive, and he became the target of a witch hunt after Eisenhower's McCarthyism. In December 1953, Eisenhower decided to conduct a security review of Oppenheimer and revoke his security franchise. At a four-week security hearing from April 12 to May 6,1954, he was charged with early leftist activities and delaying the government's strategic decision to develop a hydrogen bomb, and was even suspected of acting as a Soviet agent, it was the Oppenheimer case. The Atomic Energy Commission's Security Committee and the Atomic Energy Commission, by a 2:1 and 4:1 majority, decided to strip Oppenheimer of his security concession, this ended his political careerand his pursuit of the political ideal of international cooperation and peace through the use of atomic energy.After retiring from politics, Oppenheimer devoted himself to Institute for Advanced Study Teaching and management, developing his teaching style and management skills here, and organizing a series of important international academic events, oppenheimer, the “Father of the atomic bomb”, was a victim of the McCarthyism of the 1950s and the cold war-era panic over American complicity and frame-ups. Oppenheimer has never won a Nobel Prize, but he has achieved as much as any Nobel laureate.（译文：奥本海默（J. Robert Oppenheimer , 1904-1967）,美国物理学家，世界“原子弹之父”。
新标准大学英语(第二版)综合教程2 Unit 6 B篇练习答案及课文翻译
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2 So how do you get them to learn about science? Well, if you go into a campus bookstore youcan findout.Therearesongbooksfor biochemists,with chemical formulae set to music to make them easier to remember. Relativity is explained in a video game which is a simulation of a rocket journey through space: You can play tennis on board as the rocket speeds up or slows down. And there are cartoons to make even the most obscure scientific subjects accessible, and fun as well.
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6 The treatment of relativity in science fiction films is even more confusing. Take Star Trek: The Voyage Home (1987). As the spaceship revolves round the sun, it gathers so much speed that it moves backwards into history. But this is nonsense, not relativity. As Jones puts it, “Einstein said that nothing travels at more than the speed of light, not that the clocks will run the other way if you go fast enough.” Even Superman (1978) is baffled by the concept. It takes him a split second to fly round the earth anticlockwise to save Lois Lane, who has fallen victim to an earthquake. Jones: “Time is not like a car. It has no reverse gear.”
essenceofdecision
Essence of DecisionEssence of Decision: Explaining the Cuban Missile Crisis is an analysis, by political scientist Graham T. Allison, of the Cuban Missile Crisis. Allison used the crisis as a case study for future studies into governmental decision-making. The book became the founding study of the John F. Kennedy School of Government, and in doing so revolutionized the field of international relations. Allison originally published the book in 1971. In 1999, because of new materials available (including tape recordings of the U.S. government's proceedings), he rewrote the book with Philip Zelikow.The title is based on a speech by John F. Kennedy, in which he said, "The essence of ultimate decision remains impenetrable to the observer - often, indeed, to the decider himself."ThesisWhen he first wrote the book, Allison contended that political science and the study of international relations were saturated with rational expectations theories inherited from the field of economics. Under such a view, the actions of states are analyzed by assuming that nations consider all options and act rationally to maximize their utility.Allison attributes such viewpoints to the dominance of economists such as Milton Friedman, statesmen such as Robert McNamara and Henry Kissinger, disciplines such as game theory, and organizations such as the RAND Corporation. However, as he puts it:It must be noted, however, that an imaginative analyst can construct an account of value-maximizing choice for any action or set of actions performed by a government.Or, to put it bluntly, this approach (which Allison terms the "Rational Actor Model") violates the law of falsifiability. Also, Allison notes that "rational" analysts must ignore a lot of facts in order to make their analysis fit their models.In response, Allison constructed three different ways (or "lenses") through which analysts can examine events: the "Rational Actor" model, the "Organizat ional Behavior" model, and the "Governmental Politics" model.To illustrate the models, Allison poses the following three questions in each section:Why did the Soviet Union decide to place offensive missiles in Cuba?Why did the United States respond to the missile deployment with a blockade?Why did the Soviet Union withdraw the missiles?The "Rational Actor" ModelThe origin of Allison's first model is explained above. Basically, under this theory: Governments are treated as the primary actor.The government examines a set of goals, evaluates them according to their utility, then picks the one that has the highest "payoff."Under this theory, Allison explains the crisis like this:John F. Kennedy, in 1961, revealed that the Soviet Union, despite rhetoric, had far fewer ICBMs than it claimed. In response, Nikita Khrushchev ordered nuclear missiles with shorter rangesinstalled in Cuba. In one move, the Soviets bridged the "missile gap" while scoring points in the Cold War. Based on Kennedy's failure to back up the Bay of Pigs Invasion, they believed the U.S. wouldn't respond harshly.Kennedy and his advisors (EXCOMM) evaluated a number of options, ranging from doing nothing to a full invasion of Cuba. A blockade of Cuba was chosen because it wouldn't necessarily escalate into war, and because it forced the Soviets to make the next move.Because of mutually assured destruction by a nuclear war, the Soviets had no choice but to bow to U.S. demands and remove the weapons.The Organizational Process ModelAllison noted there were many facts that the rational model had to ignore, such as why the Soviets failed to camouflage the nuclear sites during construction, but did so only after U-2flights pinpointed their locations.He cited work by James G. March and Herbert Simon, which argue that existing governmental bureaucracy places limits on a nation's actions, and often dictates the final outcome. He then proposed the following "organizational process" model propositions:When faced with a crisis, government leaders don't look at it as a whole, but break it down and assign it according to pre-established organizational lines.Because of time and resource limitations, rather than evaluating all possible courses of action to see which one is most likely to work, leaders settle on the first proposal that adequately addresses the issue, which Simon termed "satisficing."Leaders gravitate towards solutions that limit short-term uncertainty (emphasis on "short-term"). Organizations follow set "repertoires" and procedures when taking actions.Because of the large resources and time required to fully plan and mobilize actions within a large organization (or government), leaders are effectively limited to pre-existing plans.Under this theory, the crisis is explained thus:Because the Soviets never established nuclear missile bases outside of their country at the time, they assigned the tasks to established departments, which in turn followed their own set procedures. However, their procedures were not adapted to Cuban conditions, and as a result, mistakes were made that allowed the U.S. to quite easily learn of the program's existence. Such mistakes included such gaffes as supposedly undercover Soviet troops decorating their barracks with Red Army Stars viewable from above.Kennedy and his advisors never really considered any other options besides a blockade or air strikes, and initially, were almost unanimously in favor of the air strikes. However, such attacks created massive uncertainty because the U.S. Air Force couldn't guarantee it would disable all the nuclear missiles. Additionally, although Kennedy wanted a "surgical" air strike that would destroy the missiles without inflicting extensive damage, the existing Air Force plan required extensive bombing that would have created more collateral damage than Kennedy desired. Because the U.S. Navy already had considerable strength in the field, because there was a pre-existing plan in place for a blockade, and because Kennedy was able to communicate directly with the fleet's captains, members fell back on the blockade as the only safe option.The Soviets simply did not have a plan to follow if the U.S. took decisive action against their missiles. Khrushchev's communications indicated a high degree of desperation. Without anyback-up plan, the Soviets had to withdraw.The "Governmental Politics" ModelAfter reading works by Richard Neustadt and Samuel P. Huntington, among others, Allison proposed a third model, which takes account of court politics(or "palace politics"). While statesmen don't like to admit they play politics to get things done, especially in h igh-stakes situations such as the Cuban missile crisis, they nonetheless do.Allison proposed the following propositions for this model:A nation's actions are best understood as the result of politicking and negotiation by its top leaders. Even if they share a goal, leaders differ in how to achieve it because of such factors as personal interests and background.Even if a leader holds absolute power (i.e., the President of the United States is technically the commander-in-chief), the leader must gain a consensus with his underlings or risk having his order misunderstood or, in some cases, ignored.Related to the above proposition, the make-up of a leader's entourage will have a large effect on the final decision (i.e., an entourage of "yes men" will create a different outcome than a group of advisors who are willing to voice disagreement).Leaders have different levels of power based on charisma, personality, skills of persuasion, and personal ties to decision-makers.If a leader is certain enough, they will not seek input from their advisors, but rather, approval. Likewise, if a leader has already implic itly decided on a particular course of action, an advisor wishing to have influence must work within the framework of the decision the leader has already made.If a leader fails to reach a consensus with his inner circle (or, at least, the appearance of a consensus), opponents may take advantage of these disagreements. Therefore, effective leaders must create a consensus.Because of the possibilities of miscommunication, misunderstandings, and downright disagreements, different leaders may take actions that the group as a whole would not approve of. Allison had to admit that, because the Soviets were not as open with their internal affairs as the Americans, he simply didn't have enough data to fully interpret the crisis with this model. Nonetheless, he made the following attempt:Khrushchev came under increasing fire from the Presidium because of Kennedy's revelation of the Soviet lack of ICBMs, as well as American successes in the Berlin Airlift. Also, the Soviet economy was being stretched, and military leaders were unhappy with Khrushchev's decision to cut the size of the Red Army. Placing missiles in Cuba was a cheap and quick way for him to secure his political base.Because of the failure of the Bay of Pigs invasion, Republicans in the Congress made Cuban policy into a major issue for the upcoming congressional elections later in 1962. Therefore, Kennedy immediately decided on a strong response rather than a diplomatic one. Although a majority of EXCOMM initially favored air strikes, those closest to the president - such as his brother and Attorney General, Robert Kennedy, and special counsel Theodore Sorensen - favored the blockade. At the same time, Kennedy got into arguments with proponents of the air strikes, such as Air Force General Curtis LeMay. After the Bay of Pigs Invasion fiasco, Kennedy alsodistrusted the CIA and its advice. This combination of push and pull led to the implication of a blockade.With his plans thwarted, Khrushchev tried to save face by pointing to American missiles in Turkey, a position similar to the Cuban missiles. While Kennedy refused to move these missiles "under duress," he allowed Robert Kennedy to reach a deal with Soviet ambassador Anatoly Dobrynin, in which the Turkish missiles (which Kennedy ordered removed prior to the crisis) would be quietly removed several months later. Publicly, Kennedy also agreed never to invade Cuba.ImplicationsWhen the book was first published, Allison's primary message was that the concept of mutually assured destruction as a barrier to nuclear war was unfounded. By looking at organizational and political models, such an outcome was quite possible - nations, against what was predicted by the rational viewpoint, could indeed "commit suicide."He pointed to several inc idents in history that seemed to back this assertion. His most salient point: prior to the attack at Pearl Harbor, Japanese military and civilian leaders, including those responsible for making the decision, were fully aware that they lacked the industrial capacity and military might to win a war against the U.S. They went ahead and attacked anyway.He also believed that the organizational model explained otherwise inexplicable gaffes in military history. To return to 1941, he noted that the U.S. intercepted enough evidence to indicate that Japan was about to attack Pearl Harbor, yet the commander did not prepare. The answer, Allison revealed, was not some conspiracy, but that what the intelligence community viewed as a "threat of attack," the commander interpreted as a "threat of sabotage." This miscommunication, due to different viewpoints, allowed the attack to be pulled off successfully - as Allison sarcastically noted, having U.S. planes lined up wing-to-wing and surrounded by armed guards was a good plan for preventing sabotage, but not for surviving an aerial attack.Likewise, the political process model explained otherwise confusing affairs. Allison pointed to the decision by General Douglas MacArthur to defy his orders during the Korean War and march too far north. The reason was not a "rational" change in U.S. intentions, but rather, MacArthur's disagreements with Harry Truman and other policymakers, and how officials allowed MacArthur to make what they considered unwise moves because of concerns over political backlash due to the general's public popularity.Above all, he described using rational actor models as dangerous. By using such models (and modes of thinking), people made unreliable assumptions about reality, which could have disastrous consequences. Part of what allowed the attack on Pearl Harbor to be pulled off was the assumption that, since Japan would lose such a war, they would never dare attack. The assumption under MAD is that nobody will ever start a nuclear war because of its consequences. However, humans are not inextricably bound to act in a rational manner, which history has proven time and time again.While Allison did not claim that any of his additional two models could fully explain anything, he noted that policymakers and analysts alike would benefit from stepping away from the traditional model and exploring alternate viewpoints (although this last remark could be viewed as facetious on Allison's part).CriticismThe book is part of an ongoing argument between supporters of rational expectations theories and analysts who look for alternative explanations.Milton Friedman, in particular, countered that, even if rational expectational theories do not describe reality per se, they should be kept since they provide accurate predictions (instrumentalism). Allison countered that Friedman has not provided enough evidence to demonstrate his theories actually predict anything, and criticizes his arguments as unscientific. Another argument (again, made by Friedman) is that the information needed for Allison's bureaucratic and political models is so large that it is impractical to use in such a crisis. Allison has conceded this is true, but argued that this does not mean a person should automatically revert back to the rational actor worldview.Moreover, Allison pointed out that the "rational actor" model continues to be applied even in long-term analyses (i.e., analyses that take place long after the event or "crisis" is past). In Essence of Decision, Allison suggests that one reason for the popularity of rational actor models is that, compared to other models, they require relatively little data and provide researchers with an "inexpensive approximation" of the situation. Allison also quotes Thomas Schelling's description of rationalistic thinking and vicarious problem solving:Y ou can sit in your armchair and try to predict how people will behave by asking how you would behave if you had your wits around you. Y ou get, free of charge, a lot of vicarious, empirical behavior.Finally, in Allison's first edition (1971), he was unable to fully explore his theories because much of the information was still classified. As a result, he made a number of assumptions on his own part. Following the collapse of the Soviet Union and the release of American recordings of EXCOMM, this new information (included in the revised 1999 edition) sometimes agreed with Allison's assumptions, but sometimes didn't.For example, in 1971, he guessed that Kennedy must have made an "under the table" agreement concerning the Turkish missiles, probably using his brother as a liaison. The American tapes confirmed this.However, Allison also guessed, in 1971, that Khrushchev must have formed his own "EXCOMM," or his own committee of advisors, to aid him during the crisis, and even named the Russian leaders he believed were with Khrushchev at the time. However, the Soviet records revealed that these individuals were not present, and Khrushchev was effectively stuck alone in his office during the crisis without the type of support Kennedy had.。
拉皮尔的实验英文版本
Lapière's ExperimentIn the field of linguistics, Lapière's experiment, also known as the Lapière brothers' experiment, was a groundbreaking study conducted by French linguists Jean and Henry Lapière in the early 20th century. The aim of the experiment was to investigate the relationship between language and social class.The experiment was conducted in Paris, where the Lapière brothers collected data by asking passersby for directions. They did this in two different ways: first, by using the formal language of the upper classes, and then by using the informal language of the lower classes. They found that when they used the formal language, they were more likely to receive directions from upper-class individuals, while when they used the informal language, they received directions from lower-class individuals.This experiment demonstrated that language use is influenced by social class and that different social groups have distinct linguistic patterns. It also highlighted the importance of language in maintaining social boundaries and distinctions between different groups.The Lapière brothers' exper iment has had a significant impact on the study of linguistics, particularly in the field of sociolinguistics. It has helped to shape our understanding of the role of language in social identity and interaction, and has provided valuable insights into the complex relationship between language and society.。
坚持不懈 英语作文
Perseverance is a quality that can lead to great achievements in life.It is the ability to continue working towards a goal despite facing obstacles and setbacks.Here are some points to consider when writing an essay on the topic of perseverance:1.Definition of Perseverance:Begin your essay by defining what perseverance means.It is the continuous effort to achieve a goal,even when faced with challenges.2.Importance of Perseverance:Explain why perseverance is important.It is a key to success in various fields such as academics,sports,business,and personal growth.3.Historical Examples:Provide examples of individuals who have demonstrated perseverance.Thomas Edisons numerous attempts to create a practical light bulb,or Abraham Lincolns multiple political defeats before becoming the President of the United States,are classic examples.4.Overcoming Failure:Discuss how perseverance helps individuals to overcome failure. It allows them to learn from their mistakes and keep moving forward.5.Developing Perseverance:Offer suggestions on how one can develop the habit of perseverance.This could include setting realistic goals,maintaining a positive attitude, and seeking support from others.6.Personal Stories:If you have personal experiences with perseverance,share them.This adds a personal touch and makes the essay more relatable.7.Quotes and Sayings:Incorporate quotes from famous individuals who have spoken about perseverance.For instance,The only limit to our realization of tomorrow will be our doubts of today.Franklin D.Roosevelt.8.Conclusion:Summarize the main points of your essay and reiterate the significance of perseverance.Encourage readers to embrace this quality in their own lives.9.Call to Action:End your essay with a call to action,urging readers to apply the lessons of perseverance in their own lives and to inspire others to do the same.Remember to structure your essay with a clear introduction,body paragraphs that explore each point in depth,and a strong conclusion that leaves a lasting impression on your e evidence and examples to support your arguments and make your essay more persuasive.。
2025届江西省萍乡市高三英语第一学期期末联考模拟试题含解析
2025届江西省萍乡市高三英语第一学期期末联考模拟试题注意事项：1．答卷前，考生务必将自己的姓名、准考证号、考场号和座位号填写在试题卷和答题卡上。
用2B铅笔将试卷类型（B）填涂在答题卡相应位置上。
将条形码粘贴在答题卡右上角"条形码粘贴处"。
2．作答选择题时，选出每小题答案后，用2B铅笔把答题卡上对应题目选项的答案信息点涂黑；如需改动，用橡皮擦干净后，再选涂其他答案。
答案不能答在试题卷上。
3．非选择题必须用黑色字迹的钢笔或签字笔作答，答案必须写在答题卡各题目指定区域内相应位置上；如需改动，先划掉原来的答案，然后再写上新答案；不准使用铅笔和涂改液。
不按以上要求作答无效。
4．考生必须保证答题卡的整洁。
考试结束后，请将本试卷和答题卡一并交回。
第一部分（共20小题，每小题1.5分，满分30分）1．It is widely acknowledged in foreign companies that employees should be ________ in terms of innovation capability.A．examined B．evolvedC．evaluated D．encouraged2．--- I’m afraid the company will not hire me.--- Come on, Bill, relax! Y ou have a lot of experience and fine references and your college work is ideal background for them. ______________A．It'll be no sweat. B．All good things come to an end.C．Words pay no debts. D．Don't give me any jaw.3．We’ll go early．，we may not get a seat．A．Otherwise B．Meanwhile C．However D．Besides4．____ which university to attend, the girl asked her teacher for advice.A．Not knowing B．Knowing not C．Not known D．Known not5．makes me stressed is the entrance examination is coming nearer and nearer.A．It; what B．What; that C．What; what D．That; that6．________ left the door unlocked must be held responsible for the accident. A．Whomever B．WhoeverC．Whatever D．Whenever7．They are smiling. There ______ much trouble solving the problem.A．couldn’t be B．mustn’t beC．can’t have been D．mustn’t have been8．As is expected, AI is an area _______ China may appear as a leading force.A．that B．whereC．which D．when9．Reporters asked him to ______ his position on welfare reform.A．clarify B．divide C．instruct10．Thanks to the efforts in environmental protection, the wetland has been _____ to its original appearance.A．restored B．deliveredC．transferred D．drafted11．The film Mei Lanfang, Li Ming plays the starring role,has again drawn the world’s attention to our traditional Chinese art.A．what B．that C．which D．where12．Life teaches us not to regret over yesterday, for it ________ and is beyond our control.A．passed B．will passC．has passed D．had passed13．一Did you forget your promise, dear?一I have finished my homework on time, mom.A．Excuse me. B．Surely.C．Why not? D．How could I?14．The police have anyone with information to come forward and talk to them.A．appealed to B．attended toC．responded to D．attached to15．From his expression, I don’t think he could have finished his homework last night, _______?A．couldn’t he B．do IC．did he D．h asn’t he16．The deal，next week，will allow Charney to make a great fortune in the stock market.A．completed B．being completedC．to be completed D．having been completed17．A hearty laugh relieves physical tension, _____your muscles relaxed for over half an hour.A．to leave B．left C．leaving D．leave18．The doctor’s dilemma was _____ he should tell the patient the truth.A．whether B．whichC．that D．what19．Not until he left his home __________ to know how important the family was for him．A．did he begin B．had he begun C．he began D．he had begun 20．—Do you like the mobile game Traveling Frog?—Yes, the posts about the virtual green frog ________ over 4 million times.A．have read B．have been readC．would be read D．are reading第二部分阅读理解（满分40分）阅读下列短文，从每题所给的A、B、C、D四个选项中，选出最佳选项。
Limits Of The Final Exam (2012)
Translation (Unit1 ~ Unit3)在得到加利福尼亚大学伯克利分校的研究生奖学金后，玛丽对人类行为各个方面的研究产生了浓厚的兴趣。
她渴望今早完成计划中的各项实验。
当前，她特别想搞清楚优雅的举止在商业谈判中具有何种举足轻重的分量。
玛丽很高兴理查德·辛格教授将指导她的研究工作。
虽然辛格教授是位著名的行为科学方面的专家，他所主持的研讨班在社会科学的学生中很有名气，但她和辛格教授却只是面熟。
她希望她的研究结果能够通过媒体广为流传，以便从事商业谈判的人们能够从她的研究中受益。
Having been granted a fellowship at the University of California at Berkeley, Mary’s interest in research on all dimensions of human behavior has come alive. She is now itching to carry out the various experiments she has planned as soon as possible. At present she is particularly keen on finding out how important a role graceful manner can play in business negotiations. Mary is glad that Professor Richard Singer will supervise her research. Although she knows him only by sight, he is a distinguished expert whose seminars enjoy an impressive reputation among students of social science. She dreams that her findings will be circulated widely through the help of the media so that people engaged in business negotiations will benefit from them.受骗的或是买了有缺陷的产品的消费者有权拿到退款、更换产品，或求得其他补救方法(remedy)。
Try New Things：Unlocking a World of Possibilities
Try New Things: Unlocking a World ofPossibilitiesHave you ever felt like life is a bit monotonous, like you're stuck in a routine that never changes? Well, I used to feel that way too, until I decided to embrace the thrill of trying new things. It's like opening a door to a whole new world, filled with colors, adventures, and endless possibilities.One sunny afternoon, I decided to step out of my comfort zone and try rock climbing. At first, the idea of scaling a towering rock face seemed terrifying. But as I put on the harness, gripped the first handhold, and started my ascent, I realized that fear was just a paper tiger. With each step, my confidence grew, and by the time I reached the top, I felt like I had conquered not just the rock, but also my own doubts. The view from the top was breathtaking, a reward for pushing myself to try something new.Another time, I joined a local book club, something I never thought I'd enjoy. I'd always considered myself more of a "visual learner," preferring movies and TV shows over reading. But the discussions were lively, the books fascinating, and I discovered a new passion for literature. It showed me that there's always more to learn and appreciate, even in areas you might initially think you'renot interested in.Learning a new language was another adventure. I chose Spanish, partly because I love Spanish music and partly because I dreamed of traveling to Spain. The journey was challenging, filled with grammar rules, vocabulary lists, and pronunciation struggles. But every time I managed to hold a basic conversation with a native speaker, or understood a song without looking up the lyrics, it felt like winning a small victory.Trying new things has taught me resilience, patience, and the joy of discovery. It's not always easy; sometimes, I've failed and felt discouraged. But those moments of setback are just as valuable as the successes, because they teach me how to pick myself up, learn from my mistakes, and keep going.Moreover, trying new things has broadened my horizons, making me more empathetic and understanding. It's helped me connect with people from different backgrounds, share stories, and appreciate the diversity of human experiences.In conclusion, trying new things is like unlocking a treasure chest of opportunities. It makes life more exciting, enriches our experiences, and helps us grow into more well-rounded individuals. So, don't be afraid to step out of your comfort zone. Embrace the unknown, and you'll find a world of wonders waiting for you.。
我和我的英语老师共度良宵作文
我和我的英语老师共度良宵作文全文共3篇示例，供读者参考篇1A Night to Remember with My English TeacherIt was just another boring Friday night. I had finished all my homework and was mindlessly scrolling through social media, looking for something to fill the void of loneliness. That's when I got the notification - an email from my English teacher, Ms. Roberts."Jeremy, I noticed you've been struggling with your writing assignments lately. I'm offering extra help sessions on Saturday mornings for students who need it. Let me know if you'd like to join."At first, I was going to ignore it. Who wants to spend their Saturday morning at school? But then I thought about my grade, which had been slipping lately. Maybe a little extra help wouldn't be the worst idea.I replied, saying I would come to the extra session. Ms. Roberts responded almost immediately with the details - we would meet at 9am in her classroom. I set an alarm, dreadinghaving to wake up early on a Saturday, but knowing it was for the best.The next morning, I dragged myself out of bed and got ready for the day. I grabbed a bagel and headed to campus, trying my best to shake thegrogginess from my body. When I arrived at Ms. Roberts' room, I was surprised to find that I was the only student there."Jeremy, thank you for coming," Ms. Roberts said warmly as I walked in. She was a younger teacher, probably in her late 20s, with dark hair pulled back in a ponytail. I had always found her very attractive, but tried not to dwell on that fact.We got to work right away, going over my previous essays and the comments she had left on them. I could tell she had put a lot of thought and effort into giving me constructive feedback. For the first time, I felt like I truly understood where I was struggling and how to improve.The hours seemed to fly by as we worked together. Before I knew it, it was almost noon. "Why don't we take a break for lunch?" Ms. Roberts suggested. "My treat."I was about to protest, not wanting to impose, but my rumbling stomach betrayed me. "That would be great, thanks," I replied.We decided on the cafe down the street from campus. It was a small, cozy place with mismatched furniture and tons of funky art covering the walls. Definitely Ms. Roberts' vibe.Over sandwiches and iced coffees, the conversation veered away from academics. Ms. Roberts asked me about my hobbies, my family, my plans for after graduation. I was surprised by how easy it was to open up to her. There was something about the way she really listened, devoid of any judgment, that made me feel comfortable.Eventually, the subject turned to her life. I learned that she had just moved to the city a year ago after finishing her Master's degree. She didn't have any family in the area, so her social circle was fairly small. I felt a strange sense of protectiveness come over me, not liking the thought of this amazing woman being alone."You know, if you're ever looking for something fun to do, I could show you around," I blurted out before I could stop myself. "You know, the cool spots that only a local would know about."For a horrible second, I regretted my words, worried I might have crossed a line. But then Ms. Roberts smiled that warm, bright smile of hers. "You know what, Jeremy? I would really like that."And just like that, a plan was formed for me to take Ms. Roberts on a grand tour of the city that weekend, exploring all the hidden gems and hot spots. A tiny part of me wondered if this was maybe skirting some boundaries of the student-teacher relationship. But I quickly quieted that voice. This was just two new friends getting to know each other better. Nothing weird about that, right?We spent the rest of the afternoon mapping out our adventure. Museums, parks, restaurants, live music venues - anywhere and everywhere I thought Ms. Roberts would enjoy. With every place I suggested, her eyes lit up more and more with excitement. It was incredible to see someone so vibrant and full of life.Before I knew it, the sun had begun to set outside the cafe's windows. Had we really been there for over six hours? It felt like no time at all."We should probably get going," Ms. Roberts said, somewhat regretfully. "But I can't wait for tomorrow."That night, as I lay in bed, replaying the day's events, an unfamiliar feeling washed over me. Contentment. Happiness. A sense of hope for the future, and not just my own.For once, the future didn't seem quite so daunting. Because no matter what happened, I knew I would have Ms. Roberts by my side, guiding me, supporting me. My teacher, yes. But also, my friend. And who knew what other potential that relationship might hold?The next day was like a dream. The two of us wandering the city, talking, laughing, sharing stories. With each place we visited, the chemistry between us grew more undeniable. Fingers brushing arms as we walked side-by-side. Locking eyes from across a crowded room, sending electric shocks straight to my core.By the time the night drew to a close with drinks at a rooftop bar, offering a breathtaking view of the city skyline, I knew there was no going back. I had fallen hard for my English teacher, Ms. Roberts. And based on the longing looks she kept giving me, I had a sneaking suspicion the feeling was mutual.As we descended back down to the street level, she pulled me aside, out of the flow of FridayNight revelers. "Jeremy," she said, her voice thick with something I couldn't quite put myfinger on. "I don't know what this is between us. But I do know that I've never felt this wayabout anyone before. Certainly not a student."She took a deep breath, steadying herself. "I'm going to be completely honest. I'm incredibly attracted to you. You're smart, insightful, kind - everything I could hope for in a partner."I felt like I had been submerged in ice water, but at the same time, like a fire was burning from within me. This wasn't just a fantasy anymore. This was real."Ms. Roberts...Megan..." I tested out using her first name, and she nodded in approval. "I feel the exact same way. About you, about everything. And please, don't worry about the student-teacher thing. I'll be graduating in a few months anyway."Megan reached out, taking my hand in hers. Her skin blazed against mine, otherworldy temperatures that were somehow exactly what I craved."Well then," she purred, a mischievous grin playing on her lips. "Why don't we get out of here? I live just a few blocks away. And I can think of much better uses for my curriculum than reading and writing."She pulled me close as we headed for her apartment, our bodies swaying in sync like dancers performing some intricate routine. That night, Megan did indeed show me just how thorough her curriculum could be.What followed was a whirlwind romance unlike anything I had ever experienced. Yes, there was the intense, passionate intimacy that came with finally unleashing those pent-up desires. But there was so much more than that. Long walks, deep conversations, sharing our hopes and fears and dreams.With Megan, for the first time in my life, I felt truly seen and accepted for who I was. She pushed me to be the best version of myself, to live up to my fullest potential. And in turn, I gave her something equally as valuable - the unconditional love and support she had been so desperately craving.Was our relationship unorthodox? Maybe to some. But to us, it was simply the cosmic forces of the universe conspiring to bring two soulmates together against all odds.A few months later, I walked across the stage at graduation, diploma in hand, ready to take on the world. There was only one regret - that Megan and I could no longer have the passionate, forbidden romance of student and teacher. But in its place, something beautiful was born.A true partnership, with a bond that transcended any labels or norms society might try to put on it. An unstoppable force of nature that nothing could put asunder.So yes, you could say that Megan Roberts was one hell of an English teacher. Just maybe not in the way you're thinking. The way she taught me about life, love, and the courage to follow my heart no matter where it leads? Well, those were the most important lessons I could have received.My only hope is that one day, I can return the favor. Imparting my own wisdom and leaving this world just a little better than I found it. Just like my dearest Megan did for me, on that one fateful, magical night that changed everything.篇2A Night to Remember with My English TeacherIt was a crisp autumn evening, the kind where you could feel the chill in the air but it wasn't quite cold enough for a jacket. I was making my way across campus to Professor Wilson's office for my weekly one-on-one English tutoring session. Trying not to be late, I quickened my pace as the old ivy-covered building came into view.Professor Wilson was my English Literature professor, but also one of the faculty members who offered private tutoring sessions in the evenings. I had been struggling in her class, despite putting in a huge effort, so I jumped at the chance to get some extra help. Plus, she was known as one of the best English professors on campus - brilliant but also kind and approachable. Any student would be lucky to get extra one-on-one time with her.I knocked on her office door at exactly 7pm and heard her welcoming voice call out "Come in!" I entered to find her seated at her desk, surrounded by towers of books and papers as usual. Despite the scholarly chaos, she looked perfectly poised in her maroon silk blouse and black pencil skirt."Good evening, Michael," she said warmly, gesturing to the chair across from her desk. "Please, have a seat. What would you like to go over tonight?"I pulled out the battered copy of poetry anthology we had been studying in class. "I'm still really struggling to analyze the symbolism and deeper meaning in these poems. Could we go through a few examples?""Of course," she replied, rolling her chair over to sit next to me. She had a gentle way of explaining things that made even the most obscure metaphors seem obvious in retrospect.We spent the next couple of hours meticulously going through several poems, breaking down layers of meaning line by line. Time became irrelevant as we got absorbed in literary analysis and debate. Despite poetry initially being a weak point for me, I could feel my comprehension steadily improving thanks to Professor Wilson's expert guidance.At some point, she must have noticed me suppressing a yawn. "Oh Michael, I've worked you too hard tonight. Why don't we take a break?" She stood up and moved towards the vintage record player in the corner of her office. "Some music, I think."Soft jazz melodies soon filled the room as she took a seat on the small loveseat, patting the open space next to her in invitation. I moved over and sat down beside her, the floral fragrance of her perfume surrounding me. We sat in comfortable silence for a few moments, listening to the music."You know Michael, you have such a keen mind for analysis," she said after a while. "Physical poetry, emotional poetry - you grasp the nuances once they're properly explained." Her eyeslocked onto mine with an intense yet warm expression. "I love working with a student who soaks up knowledge like you do."Heat rose to my cheeks at her praise. This brilliant, beautiful woman thought so highly of me - it was almost too much for my 19-year-old brain to process. We sat in silence once more, the air thick with chemistry that a mere student like myself wasn't quite sure how to navigate.Finally, Professor Wilson spoke again, her melodious voice tinged with wistfulness. "Michael, have you ever been in love? Truly, deeply in love?"I swallowed hard, feeling somewhat out of depth. My experience was limited to fumbling teenage flings at best. "I...I'm not sure, Professor. Perhaps I've convinced myself I was in love before, but in hindsight it was merely infatuation."Her eyes softened as she regarded me intently. "Love is a delicious agony, filled with symbolism longing to be unraveled. Like the most complex poem, love reveals new layers of meaning the more you study it."Before I could respond, she continued in an impassioned tone. "Love provides the inspiration for all great poetry and art! To truly experience it is to unlock the door to the deepestcreative understanding."She placed her hand atop mine, sending shockwaves through my body at her touch."That's what you need, Michael. A great love to serve as your poetic muse."In that heated moment, it felt like the entire universe had contracted until just the two of us remained. I drowned in the depths of her sage-colored eyes, mesmerized by her beauty and the suggestive nature of her words. Was she really saying what I thought she was?Then, as if in a dream, Professor Wilson began leaning towards me, her rouged lips slightly parted in invitation. This was really happening! Years of pining for her from afar, and she wanted me after all.篇3My English Teacher and I Spent a Good Night TogetherBeing an international student in an English-speaking country, mastering the language has been one of my biggest challenges. I've tried everything - tutors, language apps, even watching TV shows and movies in English. But nothing seemed to help me overcome that mental barrier and gain true fluency.That is, until I met Mrs. Thompson, my English literature teacher this semester. From the first day of class, I could tell she was different than my other English instructors. She had this warmth and passion that drew me in and made me want to engage more deeply with the material. Rather than just lecturing at us, she encouraged discussion and debate, pushing us to really analyze the texts.At first I was hesitant to speak up, afraid my shaky English skills would embarrass me in front of the whole class. But Mrs. Thompson created such a supportive environment, gently correcting any mistakes without making me feel small. Slowly but surely, I started raising my hand more and more.A few weeks into the semester, I stayed after class one day to ask Mrs. Thompson a question about the reading assignment. Before I knew it, we had launched into a fascinating discussion about the themes of the novel, talking for over an hour. Her insights were so rich and thought-provoking. I felt myself becoming bolder in expressing my interpretations too.From then on, I made a habit of visiting Mrs. Thompson during her office hours. We'd have these incredible conversations, ranging from literature to philosophy to sharing stories about our lives and cultures. With each chat, mycomprehension and conversational abilities grew by leaps and bounds. Mrs. Thompson was just so gifted at explaining concepts in a clear, engaging way.She never made me feel like I was imposing or wasting her time either. If anything, she seemed to enjoy our talks just as much as I did. There was such a natural rapport between us, almost like we were colleagues or friends instead of student and teacher.As the semester progressed, I looked forward to my meetings with Mrs. Thompson more and more. They became a highlight of my week, a safe space where I could explore ideas without judgment and immerse myself in intelligent discourse. I'm quite shy by nature, but around her I felt comfortable opening up and being my full, authentic self.With each conversation, I felt the mental fog around the English language dissipating. Words and ideas started flowing more freely. My vocabulary expanded, my accent and grammar improved. Mrs. Thompson's guidance showed me how mastering a language is about so much more than just memorizing vocabulary lists. It's about engaging with the rich cultures and perspectives it opens you to.Looking back at my progress from the start of term to the end, I'm amazed by how much my English has transformed. I actually feel confident expressing myself now, comfortable weaving between formal academic discussions and casual daily interactions. I no longer get flustered searching for the right words or worrying about making mistakes.Of course, none of this would have been possible without Mrs. Thompson's mentorship and encouragement every step of the way. Our private chats were invaluable, but she also pushed me to participate more actively in class discussions too. Thanks to her nurturing presence, I eventually overcame my shyness and fear of judgment from my classmates.The night before our final exam, I'll never forget the private review session Mrs. Thompson held for any students who wanted some last-minute prep. It was just myself and a couple other eager beavers who showed up at her office after normal hours.As we went over key concepts and analyzed sample essay prompts, Mrs. Thompson was her usual energetic, engaging self. She had this remarkable ability to break down complex ideas into easy-to-understand chunks without dumbing anything down. I felt like I was really internalizing and cementing everything at a deeper level.Even after we ostensibly covered all the important material for the test, none of us wanted the session to end! We had veered off onto so many fascinating intellectual detours and musings, debating themes and philosophies from the literary works we studied. The conversation flowed so naturally and passionately, with each of us building off each other's insights in a dynamic exchange of perspectives.Before any of us realized it, the invigorating discussion had carried us late into the night. When Mrs. Thompson finally glanced up at the clock around 2am, her jaw dropped in surprised delight. "Oh my, look how carried away we all got! What a lively, engaging bunch of minds you all are - it's been an absolute joy exploring these concepts with you tonight."None of us students felt even the slightest bit tired though. The fascinating discourse had reenergized us, leaving our brains buzzing with So many new connections and epiphanies. We could have stayed up analyzing literature and philosophizing until the sun came up!As we exchanged goodnights and gathered our things, I felt profoundly grateful for Mrs. Thompson and all she had done for me. More than just helping me grasp the English language, she had been the ultimate teacher and mentor. She didn't justconvey knowledge, she ignited a deeper passion for learning, thinking critically, and fearlessly exploring new ideas.Mrs. Thompson saw so much potential in me that I couldn't even see in myself sometimes. Her caring guidance gave me the courage and confidence to shed my shyness and insecurity around English. More than just a language now, it felt like a doorway into an entire world of art, culture, and intellectual fulfillment that I finally had the keys to access.As I walked home that early morning, my mind was still abuzz from the night's stimulating exchange of ideas. For once though, the swirl of thoughts wasn't stressful or frustrating - it flowed coherently, my brain naturally processing the new connections and insights in English without any mental strain.In that moment, I realized just how comfortable I had become in fully expressing myself and grappling with complex concepts in English. What once felt like an agonizing uphill battle now felt like second nature, as natural as breathing. All because an exceptional teacher spent countless patient hours mentoring me, challenging me, and believing in me.That late-night review session with Mrs. Thompson was so much more than just exam prep. It was the culminating celebration of an entire semester's worth of hard work, growth,and intellectual awakening for me. I can't put into words how grateful I am that she went so far above and beyond, voluntarily giving up her evening to engage her students in discussions that fed our minds and souls.I know with 100% certainty that I would not have reached this level of English fluency and confidence without Mrs. Thompson's nurturing support. The progress I've made this term is nothing short of life-changing. What once felt like forbidding language barrier has been joyfully overcome, allowing me to engage with the world through an entirely new lens.As I begin looking ahead to next semester, I feel a bittersweet sadness knowing my weekly heart-to-heart tutorials with Mrs. Thompson are coming to an end. But I'll carry the lessons and gifts she's given me for the rest of my life. Most of all, I hope to one day be able to pass along her passion for learning and empowering others, just as she has so incredibly done for me.。
灵感绘梦绘风景的英语作文
Inspiration is the spark that ignites the creative flame within us.It is the invisible force that guides our thoughts and actions,leading us to envision and create beautiful landscapes and dreamscapes.When we allow ourselves to be open to inspiration,we can transform the ordinary into the extraordinary,and the mundane into the magical.To begin with,inspiration can come from a variety of sources.It may be a beautiful sunset that paints the sky with hues of orange and pink,or a serene lake that reflects the tranquility of nature.It could be a powerful piece of music that stirs our emotions,or a captivating book that takes us on a journey to another world.The key is to be receptive to these stimuli and to let them fuel our imagination.Once we have been inspired,we can begin to translate these feelings and images into our own unique creations.This process often involves a combination of observation, reflection,and experimentation.By carefully observing the world around us,we can identify the elements that resonate with us the most and incorporate them into our work. Reflection allows us to delve deeper into our thoughts and emotions,helping us to understand what it is about a particular image or idea that moves us.Experimentation is an essential part of the creative process.It is through trial and error that we discover new techniques and approaches that can help us to bring our visions to life.This might involve trying out different mediums,such as watercolors or oils,or experimenting with various compositional techniques,like the rule of thirds or the use of leading lines.As we continue to develop our skills and refine our artistic voice,we may find that our work begins to take on a life of its own.Our dreams and aspirations can be reflected in the landscapes we create,with each brushstroke and color choice telling a story of hope, ambition,and wonder.In this way,our art can serve as a bridge between our inner world and the external reality,allowing us to share our dreams and inspire others in the process.Moreover,the act of creating can be a deeply therapeutic and fulfilling experience.It provides an outlet for selfexpression and a means of exploring our emotions and experiences in a safe and constructive way.By immersing ourselves in the world of our imagination,we can find solace and a sense of connection to something greater than ourselves.In conclusion,inspiration is a powerful catalyst for creativity and personal growth.By embracing the beauty of the world around us and allowing ourselves to be guided by our dreams and aspirations,we can create landscapes and dreamscapes that are both visuallystunning and emotionally resonant.In doing so,we not only enrich our own lives but also have the potential to inspire and uplift those who encounter our work.。
突破了自己的极限英语作文
突破了自己的极限英语作文I remember the first time I tried to speak English. It was nerve-wracking. I stumbled over my words and my pronunciation was terrible. But I didn't let that stop me.I kept practicing and pushing myself to improve. And now, I can confidently say that I have surpassed my own limits in English.It's amazing how language can connect people from different cultures and backgrounds. When I first started learning English, I never imagined that I would be able to have conversations with people from all over the world. But here I am, chatting with friends from the United States, Australia, and even England. It's a truly remarkable experience.One thing that really helped me improve my English was immersing myself in the language. I started watching movies and TV shows in English, listening to English music, and even reading books in English. It was challenging at first,but it forced me to think in English and helped me become more comfortable with the language.Another thing that pushed me to break my limits in English was traveling to English-speaking countries. Being surrounded by native speakers forced me to use the language in real-life situations. It was intimidating at times, but it also gave me the opportunity to practice and improve my skills.Of course, there were times when I felt frustrated and wanted to give up. English can be a difficult language to master, with its complex grammar rules and pronunciation challenges. But I reminded myself that progress takes time and effort. I celebrated the small victories along the way, like successfully ordering food in English or understanding a joke in a movie.Now, I feel more confident in my English abilities than ever before. I still have a lot to learn, but I am proud of how far I have come. English has opened up so many doorsfor me, both personally and professionally. I am gratefulfor the opportunities it has given me and excited to continue pushing myself to reach new heights in the language.In conclusion, breaking my limits in English has been a journey filled with ups and downs. It required dedication, perseverance, and a willingness to step out of my comfort zone. But it has been worth it. I have gained so much more than just language skills – I have gained a new perspective on the world and a sense of accomplishment. English has become a part of who I am, and I am excited to see where it will take me next.。
在线考试系统外文文献
1877-0428 © 2012 Published by Elsevier B.V. Selection and/or peer-review under responsibility of EUROCALL2010 Scientific Committee doi: 10.1016/j.sbspro.2012.02.015P rocedia - Social and Behavioral Sciences 34 ( 2012 ) 68 – 72Languages, Cultures and Virtual CommunitiesLes Langues, les Cultures et les Communautés VirtuellesImplementing online language exams within the SpanishNational University Entrance Examination: The PAULEXUniversitas ProjectAna Gimeno-Sanz * & Jose Macario de SiqueiraCAMILLE Research Group, Department of Applied Linguistics, Universidad Politécnica de Valencia, Camino de Vera 14, 46022Valencia, SpainAbstractThis paper describes the PAULEX Universitas Project, an online system to design, deliver and assess the foreign language exam that is an integral part of the Spanish national university entrance examination. The foreign language exam is compulsory for all students who wish to enrol in higher education. Students can choose to take one of the following language exams: English, French, German, Italian or Portuguese. Every year, approximately 27,000 students take the university exam simultaneously in the Valencian Community (comprised of 3 provinces: Alicante, Castellón and Valencia) and over 25,000 of these take the English language exam. The paper describes the context in which this university entrance exam takes place, with reference to the current changes in Spanish ministerial policies. Illustrations from the platform are included, as well as a dis cussion on issues relating to the system’s management tools, data security and user interaction. The paper concludes by presenting some of the results obtained from a pilot experience conducted in Valencia with more than 200 students and by addressing a number of difficulties encountered concerning the implementation of the PAULEX online examination platform regionally.© 2012 Published by Elsevier Ltd. under responsibility of Dominique Macaire and Alex BoultonKeywords : Spanish University Entrance Examination; online testing; computer-assisted language testing; official language exams; PAULEX project* Gimeno-Sanz. Tel.: +34 963 877 530; Fax: +34 963 879 98agimeno@upvnet.upv.esAvailable online at © 2012 Published by Elsevier B.V . Selection and/or peer-review under responsibility of EUROCALL2010 Scientific Committee69A na Gimeno-Sanz and Jose Macario de Siqueira / P rocedia - Social and Behavioral Sciences 34 ( 2012 )68 – 721.IntroductionIn December 2008 the Spanish Ministry of Education published a new law to regulate the national University Entrance Examination1. This new law2 establishes that the English language exam, which had traditionally been based on reading comprehension exercises and written production, should now include assessment of listening comprehension as well as speaking skills. This happily coincided in time with aproject proposal submitted to the Spanish Ministry of Science and Innovation to design a computer platform to deliver the foreign language exam within the official university entrance examination. Taking previous work conducted by the CAMILLE R&D Group3 at the Universidad Politécnica de Valencia as astarting point –namely, the InGenio authoring tool and delivery environment (Gimeno 2008a and 2008b)–the group members set about designing a completely online platform to a) design the foreign languageexam, b) deliver it online, c) assess the completed exams, and d) supply the exam results to the local examining board. The three-year project ran from September 2007 till the end of 2010.2.PAULEX UniversitasThe PAULEX online exam delivery platform is controlled by a Central Server (CS), located within the University’s central Information and Communications Systems unit, through which the administrators manage access to the system. A second server is constantly duplicating all the information from the CSand making backup copies automatically should it be necessary to replace the CS, to work on it or torepair any of its components. The contents and the platform could also be managed and run on any other external web servers should the platform finally be implemented to manage and deliver the foreign language exam within the Spanish University Entrance Examination. In Spain, every autonomous community or region manages its own university entrance examinations. In our case, it is the Departmentof Education of the regional government of the Valencian Community who is in charge of administratingthese exams in collaboration with the public universities located in its territory4.Figure 1. The PAULEX platform structure and connectionThe PAULEX platform is basically structured into two main parts: the database and the programmecode. The database is developed through PostgreSQL, one of the most efficient open source database1 In Spanish, the exam is known as Pruebas de Acceso a la Universidad (PAU).2 Real Decreto 1892/2008. Available from http://www.boe.es/boe/dias/2008/11/24/pdfs/A46932-46946.pdf3 The CAMILLE R&D Group comprises language specialists, graphics designers and computer engineers.4 There are five public universities in the Valencian region: Universidad Jaume I de Castellón; Universidad de Valencia;Universidad Politécnica de Valencia; Universidad de Alicante, and Universidad Miguel Hernández de Elche.70A na Gimeno-Sanz and Jose Macario de Siqueira / P rocedia - Social and Behavioral Sciences 34 ( 2012 )68 – 72 management systems available on the Internet. The programme code is especially designed for the web using PHP, HTML, XML and JavaScript languages. The multimedia archives saved on the server are also part of the PAULEX database, allowing administrators to build up an abundant pool of images and audio and video files, in addition to the audio files created by students when completing the oral section of the exam through the voice-recording system. Figure 1 illustrates how users access the platform and adopt specific roles (administrators, exam writers, students and assessors/exam markers). Each of these users has a specific graphical user interface through which they communicate with the CS. The only system requirements are a live Internet connection and a specific plug-in to reproduce audio and video and to record the students’ utterances.Figure 2. Exam writer’s interface within the PAULEX p latform3.The first pilot experimentThe project was conceived as an attempt to design and to test the feasibility of implementing a computer-assisted foreign language exam within the official University Entrance Examination in the Valencian Community. The newly approved regulations determined, for the first time ever, that listening comprehension and speaking skills would also be included in the exam as from June 2012. As the information included in the new legislation dealing with the revamped exam is extremely brief and general, the CAMILLE R&D Group designed and distributed a questionnaire among secondary school teachers who teach English in the second year of Bachillerato5 from the three Valencian provinces (Alicante, Castellón and Valencia). The main goal was to discover – given their first-hand experience –which exercise typologies they thought would better suit the assessment of all four language skills in an online environment. The results of the questionnaires and the current exam format were then combined to produce a new exam that integrated all four skills (reading, writing, listening and speaking). This pilot exam was then taken in a simulated authentic environment by 200 students who were due to take the 5 The second year of Bachillerato is the last year in Spanish secondary education. All students wishing to enter university must do the first and second years of Bachillerato and then take the university entrance examination.71A na Gimeno-Sanz and Jose Macario de Siqueira / P rocedia - Social and Behavioral Sciences 34 ( 2012 )68 – 72official exam in June 2010. After completing the exam, the students were requested to fill in an opinion questionnaire which was designed to collect information regarding their computer-literacy, their everydayuse of computers, their willingness to take the exam using the PAULEX online platform, their response to recording their own utterances in a file for subsequent assessment, etc.Figure 3. Sample speaking exerciseThe results were extraordinarily satisfactory in every sense. The students who took the online examfelt that the platform was user-friendly, especially when editing their answers, watching video files and speaking into the microphone to record their voice in response to a video recorded question. There searchers had made a special effort to include topics that would trigger the students’ interest and focused the entire exam on current social issues. In the listening section, students watched a number ofvideos which included content and questions. They were requested to watch the video contents, listen tothe questions and then write open answers or tick multiple choice questions. The speaking section provedto be the most interesting part for research purposes. The exam included an attractive image showing thelogos of a number of popular social networks and online chat platforms. They were requested to analysethe image and speak into the microphone relating the networks to their own personal likes and experience(see Figure 3). Although they were given a four-minute slot to record their answers, very few of themused the entire time frame. Anecdotally, it was obvious throughout the trials that the students were shyand remained silent when they first approached this part of the exam. They did not start talking until oneof their partners had done so beforehand. They spoke into their microphones in a low voice so that thesystem could record their answers, but avoiding their partners hearing them.The online platform requires students to complete the exercises and, once they are satisfied with the72A na Gimeno-Sanz and Jose Macario de Siqueira / P rocedia - Social and Behavioral Sciences 34 ( 2012 )68 – 72 answer, validate each of these and any modifications they may make. Upon validation, the results are then transferred to the CS and made available to the exam markers for them to assess the parts of the exam which are not automatically evaluated by the system (open input exercises and voice recordings).4.ConclusionsTo conclude, the PAULEX platform has been presented as a robust tool to enable the administrators of the Spanish University Entrance Examination in the Valencian region to deliver the foreign language exam via the Internet. After several years of research, the computerization of this exam has been considered as one of the most achievable alternatives to face the challenges arising from the changes included in the new Spanish educational legislation. The first pilot experiment has proven extremely favourable since both secondary school teachers and students who have tested the system in real conditions are in favour of its implementation. Initial piloting showed that implementing a computer-assisted English exam as part of the Spanish University Entry Examination is not only feasible, but also recommendable. A very high percentage of students agreed that they had felt no additional strain while completing the exam online. The results have also been very satisfactory, though teachers and students have been advised not to rely on the marks obtained in the pilot trial as being equivalent to the ones that they would achieve when facing the exam in real circumstances. Most of the exercises have been assessed automatically, though personalized marking has been required for open input exercises such as the writing and the speaking tasks.AcknowledgmentsAcknowledgements are due to the Spanish Ministry of Science and Innovation for granting and funding the PAULEX Project (HUM2007-66479-C02-01/FILO).ReferencesGimeno Sanz, A. (Ed.). (2008a). Aprendizaje de lenguas asistido por ordenador: Herramientas de autor para el desarrollo de cursos a través de la web. Valencia: Editorial UPV.Gimeno Sanz, A. (2008b). Online courseware design and delivery: The InGenio authoring system. In I. González-Pueyo, C. Foz Gil, M. Jaime Siso & M. J. Luzón Marco (Eds.), Teaching academic and professional English online (pp. 83-105). Bern: Peter Lang.。
2024届新疆乌鲁木齐市六十八中高三上学期1月月考英语试题及答案
乌鲁木齐市第六十八中学高三1月月考英语试题总分120分考试时间120分钟第一部分：阅读(共两节，满分50分)阅读理解(共37.5分)ATop Summer Festivals in AustraliaSplendid mornings and glorious sunshine may not always make summer exciting, but the Aussie summer is always a nice option. The country finds its fortune, the artists find their patrons, and pleasure-seekers get that kick to enjoy good things in life under the southern sun.1. Margaret River Gourmet EscapeWhen: November 17-19This outstanding food & wine festival at Leeuwin Estate Winery by the Margaret River is an experience for travelers who have arrived at the start of summer. From enjoying barbeque on the famous Castle Bay Beach to dining on the longest wooden jetty (栈桥) in the Southern Hemisphere, the true devotees of food and wine choose entertainment for these three days.2Tropfest Film Festival.When: February 7-11Filmmakers from across the globe use the world’s largest short film festival as a platform to showcase their work. This free-to-attend festival doesn’t have the air of Cannes(戛纳) but the audience is assured of some really experimental movies. If you happen to be in Sydney this summer. head to the Centennial Park and see for yourselfhow heartwarming this festival can turn out to be.3. Womadelaide Music FestivalWhen: February 17-March5During the Womadelaide festival, you can attend this biggest world music festival in southern hemisphere. The Botanic Park tums into a Mecca (麦加) for music lovers as live concerts by artists from all over the world make you enjoy different cultures and genres. To make your summer weekend in South Australia memorable, hit the festival on the first day.4. Perth International Arts FestivalWhen: February 10-March5The Perth international arts festival in Australia is a wonderful experience. Even the “mad” summer of Perth would feel sweet when you join a noble gathering of people at this premier cultural even. This 24-day festival is an occasion to meet greatest living artists and get exposed to new works.1. What is the feature of Margaret River Gourmet Escape?A. It contains different water activities.B. It is famed for food, wines and beachesC. It is the first summer festival in the world.D. It holds an exhibition of world-class wines2. Where can visitors watch the live performances of great artists?A. In the Botanic Park.B. By the Margaret RiverC. In the Centennial Park.D. On the Castle Bay Beach.3. Which is the longest running festival in Australia?A. Tropfest Film Festivals.B. Womadelaide Music Festival.C. Margaret River Gourmet Escape.D. Perth Intemational Arts FestivalBBears eat human food when they can get some.But in a new study, the more human food 30 female black bears ate, the less time those bears were likely to spend hibernating(冬眠）．In turn,bears that hibernated less were likely to score worse in a test for aging.The new research grew out of an earlier project to see what wild black bears across Colorado were eating, says Jonathan Pauli, a researcher from the University of Wisconsin-Madison.Another researcher Rebecca Kirby checked diets of hundreds of bears across the state when she was aPh.D.student. She found that hunters there were not allowed to set out bear bait（诱饵）。
《材料科学与工程基础》英文影印版习题及思考题及答案
《材料科学与工程基础》英文习题及思考题及答案第二章习题和思考题Questions and Problems2.6 Allowed values for the quantum numbers ofelectrons are as follows:The relationships between n and the shell designationsare noted in Table 2.1.Relative tothe subshells,l ＝0 corresponds to an s subshelll ＝1 corresponds to a p subshelll ＝2 corresponds to a d subshelll ＝3 corresponds to an f subshellFor the K shell, the four quantum numbersfor each of the two electrons in the 1s state, inthe order of nlmlms , are 100(1/2 ) and 100(-1/2 ).Write the four quantum numbers for allof the electrons inthe L and M shells, and notewhich correspond to the s, p, and d subshells.2.7 Give the electron configurations for the followingions: Fe2+, Fe3+, Cu+, Ba2+,Br-, andS2-.2.17 (a) Briefly cite the main differences betweenionic, covalent, and metallicbonding.(b) State the Pauli exclusion principle.2.18 Offer an explanation as to why covalently bonded materials are generally lessdense than ionically or metallically bonded ones.2.19 Compute the percents ionic character of the interatomic bonds for the followingcompounds: TiO2 , ZnTe, CsCl, InSb, and MgCl2 .2.21 Using Table 2.2, determine the number of covalent bonds that are possible foratoms of the following elements: germanium, phosphorus, selenium, and chlorine.2.24 On the basis of the hydrogen bond, explain the anomalous behavior of waterwhen it freezes. That is, why is there volume expansion upon solidification?3.1 What is the difference between atomic structure and crystal structure?3.2 What is the difference between a crystal structure and a crystal system?3.4Show for the body-centered cubic crystal structure that the unit cell edge lengtha and the atomic radius R are related through a =4R/√3.3.6 Show that the atomic packing factor for BCC is 0.68. .3.27* Show that the minimum cation-to-anion radius ratio for a coordinationnumber of 6 is 0.414. Hint: Use the NaCl crystal structure (Figure 3.5), and assume that anions and cations are just touching along cube edges and across face diagonals.3.48 Draw an orthorhombic unit cell, and within that cell a [121] direction and a(210) plane.3.50 Here are unit cells for two hypothetical metals:(a)What are the indices for the directions indicated by the two vectors in sketch(a)?(b) What are the indices for the two planes drawn in sketch (b)?3.51* Within a cubic unit cell, sketch the following directions:.3.53 Determine the indices for the directions shown in the following cubic unit cell:3.57 Determine the Miller indices for the planesshown in the following unit cell:3.58Determine the Miller indices for the planes shown in the following unit cell: 3.61* Sketch within a cubic unit cell the following planes:3.62 Sketch the atomic packing of (a) the (100)plane for the FCC crystal structure, and (b) the (111) plane for the BCC crystal structure (similar to Figures 3.24b and 3.25b).3.77 Explain why the properties of polycrystalline materials are most oftenisotropic.5.1 Calculate the fraction of atom sites that are vacant for lead at its meltingtemperature of 327_C. Assume an energy for vacancy formation of 0.55eV/atom.5.7 If cupric oxide (CuO) is exposed to reducing atmospheres at elevatedtemperatures, some of the Cu2_ ions will become Cu_.(a) Under these conditions, name one crystalline defect that you would expect toform in order to maintain charge neutrality.(b) How many Cu_ ions are required for the creation of each defect?5.8 Below, atomic radius, crystal structure, electronegativity, and the most commonvalence are tabulated, for several elements; for those that are nonmetals, only atomic radii are indicated.Which of these elements would you expect to form the following with copper:(a) A substitutional solid solution having complete solubility?(b) A substitutional solid solution of incomplete solubility?(c) An interstitial solid solution?5.9 For both FCC and BCC crystal structures, there are two different types ofinterstitial sites. In each case, one site is larger than the other, which site isnormally occupied by impurity atoms. For FCC, this larger one is located at the center of each edge of the unit cell; it is termed an octahedral interstitial site. On the other hand, with BCC the larger site type is found at 0, __, __ positions—that is, lying on _100_ faces, and situated midway between two unit cell edges on this face and one-quarter of the distance between the other two unit cell edges; it is termed a tetrahedral interstitial site. For both FCC and BCC crystalstructures, compute the radius r of an impurity atom that will just fit into one of these sites in terms of the atomic radius R of the host atom.5.10 (a) Suppose that Li2O is added as an impurity to CaO. If the Li_ substitutes forCa2_, what kind of vacancies would you expect to form? How many of thesevacancies are created for every Li_ added?(b) Suppose that CaCl2 is added as an impurity to CaO. If the Cl_ substitutes forO2_, what kind of vacancies would you expect to form? How many of thevacancies are created for every Cl_ added?5.28 Copper and platinum both have the FCC crystal structure and Cu forms asubstitutional solid solution for concentrations up to approximately 6 wt% Cu at room temperature. Compute the unit cell edge length for a 95 wt% Pt-5 wt% Cu alloy.5.29 Cite the relative Burgers vector–dislocation line orientations for edge, screw, andmixed dislocations.6.1 Briefly explain the difference between selfdiffusion and interdiffusion.6.3 (a) Compare interstitial and vacancy atomic mechanisms for diffusion.(b) Cite two reasons why interstitial diffusion is normally more rapid thanvacancy diffusion.6.4 Briefly explain the concept of steady state as it applies to diffusion.6.5 (a) Briefly explain the concept of a driving force.(b) What is the driving force for steadystate diffusion?6.6Compute the number of kilograms of hydrogen that pass per hour through a5-mm thick sheet of palladium having an area of 0.20 m2at 500℃. Assume a diffusion coefficient of 1.0×10- 8 m2/s, that the concentrations at the high- and low-pressure sides of the plate are 2.4 and 0.6 kg of hydrogen per cubic meter of palladium, and that steady-state conditions have been attained.6.7 A sheet of steel 1.5 mm thick has nitrogen atmospheres on both sides at 1200℃and is permitted to achieve a steady-state diffusion condition. The diffusion coefficient for nitrogen in steel at this temperature is 6×10-11m2/s, and the diffusion flux is found to be 1.2×10- 7kg/m2-s. Also, it is known that the concentration of nitrogen in the steel at the high-pressure surface is 4 kg/m3. How far into the sheet from this high-pressure side will the concentration be 2.0 kg/m3?Assume a linear concentration profile.6.24. Carbon is allowed to diffuse through a steel plate 15 mm thick. Theconcentrations of carbon at the two faces are 0.65 and 0.30 kg C/m3 Fe, whichare maintained constant. If the preexponential and activation energy are 6.2 _10_7 m2/s and 80,000 J/mol, respectively, compute the temperature at which the diffusion flux is 1.43 _ 10_9 kg/m2-s.6.25 The steady-state diffusion flux through a metal plate is 5.4_10_10 kg/m2-s at atemperature of 727_C (1000 K) and when the concentration gradient is _350kg/m4. Calculate the diffusion flux at 1027_C (1300 K) for the sameconcentration gradient and assuming an activation energy for diffusion of125,000 J/mol.10.2 What thermodynamic condition must be met for a state of equilibrium to exist? 10.4 What is the difference between the states of phase equilibrium and metastability?10.5 Cite the phases that are present and the phase compositions for the followingalloys:(a) 90 wt% Zn–10 wt% Cu at 400℃(b) 75 wt% Sn–25wt%Pb at 175℃(c) 55 wt% Ag–45 wt% Cu at 900℃(d) 30 wt% Pb–70 wt% Mg at 425℃(e) 2.12 kg Zn and 1.88 kg Cu at 500℃(f ) 37 lbm Pb and 6.5 lbm Mg at 400℃(g) 8.2 mol Ni and 4.3 mol Cu at 1250℃.(h) 4.5 mol Sn and 0.45 mol Pb at 200℃10.6 For an alloy of composition 74 wt% Zn–26 wt% Cu, cite the phases presentand their compositions at the following temperatures: 850℃, 750℃, 680℃, 600℃, and 500℃.10.7 Determine the relative amounts (in terms of mass fractions) of the phases forthe alloys and temperatures given inProblem 10.5.10.9 Determine the relative amounts (interms of volume fractions) of the phases forthe alloys and temperatures given inProblem 10.5a, b, and c. Below are given theapproximate densities of the various metalsat the alloy temperatures:10.18 Is it possible to have a copper–silveralloy that, at equilibrium, consists of a _ phase of composition 92 wt% Ag–8wt% Cu, and also a liquid phase of composition 76 wt% Ag–24 wt% Cu? If so, what will be the approximate temperature of the alloy? If this is not possible,explain why.10.20 A copper–nickel alloy of composition 70 wt% Ni–30 wt% Cu is slowly heatedfrom a temperature of 1300_C .(a) At what temperature does the first liquid phase form?(b) What is the composition of this liquid phase?(c) At what temperature does complete melting of the alloy occur?(d) What is the composition of the last solid remaining prior to completemelting?10.28 .Is it possible to have a copper–silver alloy of composition 50 wt% Ag–50 wt%Cu, which, at equilibrium, consists of _ and _ phases having mass fractions W_ _0.60 and W_ _ 0.40? If so, what will be the approximate temperature of the alloy?If such an alloy is not possible, explain why.10.30 At 700_C , what is the maximum solubility (a) of Cu in Ag? (b) Of Ag in Cu?第三章习题和思考题3.3If the atomic radius of aluminum is 0.143nm, calculate the volume of its unitcell in cubic meters.3.8 Iron has a BCC crystal structure, an atomic radius of 0.124 nm, and an atomicweight of 55.85 g/mol. Compute and compare its density with the experimental value found inside the front cover.3.9 Calculate the radius of an iridium atom given that Ir has an FCC crystal structure,a density of 22.4 g/cm3, and an atomic weight of 192.2 g/mol.3.13 Using atomic weight, crystal structure, and atomic radius data tabulated insidethe front cover, compute the theoretical densities of lead, chromium, copper, and cobalt, and then compare these values with the measured densities listed in this same table. The c/a ratio for cobalt is 1.623.3.15 Below are listed the atomic weight, density, and atomic radius for threehypothetical alloys. For each determine whether its crystal structure is FCC,BCC, or simple cubic and then justify your determination. A simple cubic unitcell is shown in Figure 3.40.3.21 This is a unit cell for a hypotheticalmetal:(a) To which crystal system doesthis unit cell belong?(b) What would this crystal structure be called?(c) Calculate the density of the material, given that its atomic weight is 141g/mol.3.25 For a ceramic compound, what are the two characteristics of the component ionsthat determine the crystal structure?3.29 On the basis of ionic charge and ionic radii, predict the crystal structures for thefollowing materials: (a) CsI, (b) NiO, (c) KI, and (d) NiS. Justify your selections.3.35 Magnesium oxide has the rock salt crystal structure and a density of 3.58 g/cm3.(a) Determine the unit cell edge length. (b) How does this result compare withthe edge length as determined from the radii in Table 3.4, assuming that theMg2_ and O2_ ions just touch each other along the edges?3.36 Compute the theoretical density of diamond given that the CUC distance andbond angle are 0.154 nm and 109.5°, respectively. How does this value compare with the measured density?3.38 Cadmium sulfide (CdS) has a cubic unit cell, and from x-ray diffraction data it isknown that the cell edge length is 0.582 nm. If the measured density is 4.82 g/cm3 , how many Cd 2+ and S 2—ions are there per unit cell?3.41 A hypothetical AX type of ceramic material is known to have a density of 2.65g/cm 3 and a unit cell of cubic symmetry with a cell edge length of 0.43 nm. The atomic weights of the A and X elements are 86.6 and 40.3 g/mol, respectively.On the basis of this information, which of the following crystal structures is (are) possible for this material: rock salt, cesium chloride, or zinc blende? Justify your choice(s).3.42 The unit cell for Mg Fe2O3 (MgO-Fe2O3) has cubic symmetry with a unit celledge length of 0.836 nm. If the density of this material is 4.52 g/cm 3 , compute its atomic packing factor. For this computation, you will need to use ionic radii listed in Table 3.4.3.44 Compute the atomic packing factor for the diamond cubic crystal structure(Figure 3.16). Assume that bonding atoms touch one another, that the angle between adjacent bonds is 109.5°, and that each atom internal to the unit cell is positioned a/4 of the distance away from the two nearest cell faces (a is the unit cell edge length).3.45 Compute the atomic packing factor for cesium chloride using the ionic radii inTable 3.4 and assuming that the ions touch along the cube diagonals.3.46 In terms of bonding, explain why silicate materials have relatively low densities.3.47 Determine the angle between covalent bonds in an SiO44—tetrahedron.3.63 For each of the following crystal structures, represent the indicated plane in themanner of Figures 3.24 and 3.25, showing both anions and cations: (a) (100)plane for the rock salt crystal structure, (b) (110) plane for the cesium chloride crystal structure, (c) (111) plane for the zinc blende crystal structure, and (d) (110) plane for the perovskite crystal structure.3.66 The zinc blende crystal structure is one that may be generated from close-packedplanes of anions.(a) Will the stacking sequence for this structure be FCC or HCP? Why?(b) Will cations fill tetrahedral or octahedral positions? Why?(c) What fraction of the positions will be occupied?3.81* The metal iridium has an FCC crystal structure. If the angle of diffraction forthe (220) set of planes occurs at 69.22°(first-order reflection) when monochromatic x-radiation having a wavelength of 0.1542 nm is used, compute(a) the interplanar spacing for this set of planes, and (b) the atomic radius for aniridium atom.4.10 What is the difference between configuration and conformation in relation topolymer chains? vinyl chloride).4.22 (a) Determine the ratio of butadiene to styrene mers in a copolymer having aweight-average molecular weight of 350,000 g/mol and weight-average degree of polymerization of 4425.(b) Which type(s) of copolymer(s) will this copolymer be, considering thefollowing possibilities: random, alternating, graft, and block? Why?4.23 Crosslinked copolymers consisting of 60 wt% ethylene and 40 wt% propylenemay have elastic properties similar to those for natural rubber. For a copolymer of this composition, determine the fraction of both mer types.4.25 (a) Compare the crystalline state in metals and polymers.(b) Compare thenoncrystalline state as it applies to polymers and ceramic glasses.4.26 Explain briefly why the tendency of a polymer to crystallize decreases withincreasing molecular weight.4.27* For each of the following pairs of polymers, do the following: (1) state whetheror not it is possible to determine if one polymer is more likely to crystallize than the other; (2) if it is possible, note which is the more likely and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why.(a) Linear and syndiotactic polyvinyl chloride; linear and isotactic polystyrene.(b) Network phenol-formaldehyde; linear and heavily crosslinked ci s-isoprene.(c) Linear polyethylene; lightly branched isotactic polypropylene.(d) Alternating poly(styrene-ethylene) copolymer; randompoly(vinylchloride-tetrafluoroethylene) copolymer.4.28 Compute the density of totally crystalline polyethylene. The orthorhombic unitcell for polyethylene is shown in Figure 4.10; also, the equivalent of two ethylene mer units is contained within each unit cell.5.11 What point defects are possible for MgO as an impurity in Al2O3? How manyMg 2+ ions must be added to form each of these defects?5.13 What is the composition, in weight percent, of an alloy that consists of 6 at% Pband 94 at% Sn?5.14 Calculate the composition, in weight per-cent, of an alloy that contains 218.0 kgtitanium, 14.6 kg of aluminum, and 9.7 kg of vanadium.5.23 Gold forms a substitutional solid solution with silver. Compute the number ofgold atoms per cubic centimeter for a silver-gold alloy that contains 10 wt% Au and 90 wt% Ag. The densities of pure gold and silver are 19.32 and 10.49 g/cm3 , respectively.8.53 In terms of molecular structure, explain why phenol-formaldehyde (Bakelite)will not be an elastomer.10.50 Compute the mass fractions of αferrite and cementite in pearlite. assumingthat pressure is held constant.10.52 (a) What is the distinction between hypoeutectoid and hypereutectoid steels?(b) In a hypoeutectoid steel, both eutectoid and proeutectoid ferrite exist. Explainthe difference between them. What will be the carbon concentration in each?10.56 Consider 1.0 kg of austenite containing 1.15 wt% C, cooled to below 727_C(a) What is the proeutectoid phase?(b) How many kilograms each of total ferrite and cementite form?(c) How many kilograms each of pearlite and the proeutectoid phase form?(d) Schematically sketch and label the resulting microstructure.10.60 The mass fractions of total ferrite and total cementite in an iron–carbon alloyare 0.88 and 0.12, respectively. Is this a hypoeutectoid or hypereutectoid alloy?Why?10.64 Is it possible to have an iron–carbon alloy for which the mass fractions of totalferrite and proeutectoid cementite are 0.846 and 0.049, respectively? Why orwhy not?第四章习题和思考题7.3 A specimen of aluminum having a rectangular cross section 10 mm _ 12.7 mmis pulled in tension with 35,500 N force, producing only elastic deformation. 7.5 A steel bar 100 mm long and having a square cross section 20 mm on an edge ispulled in tension with a load of 89,000 N , and experiences an elongation of 0.10 mm . Assuming that the deformation is entirely elastic, calculate the elasticmodulus of the steel.7.7 For a bronze alloy, the stress at which plastic deformation begins is 275 MPa ,and the modulus of elasticity is 115 Gpa .(a) What is the maximum load that may be applied to a specimen with across-sectional area of 325mm, without plastic deformation?(b) If the original specimen length is 115 mm , what is the maximum length towhich it may be stretched without causing plastic deformation?7.8 A cylindrical rod of copper (E _ 110 GPa, Stress (MPa) ) having a yield strengthof 240Mpa is to be subjected to a load of 6660 N. If the length of the rod is 380 mm, what must be the diameter to allow an elongation of 0.50 mm?7.9 Consider a cylindrical specimen of a steel alloy (Figure 7.33) 10mm in diameterand 75 mm long that is pulled in tension. Determine its elongation when a load of 23,500 N is applied.7.16 A cylindrical specimen of some alloy 8 mm in diameter is stressed elasticallyin tension. A force of 15,700 N produces a reduction in specimen diameter of 5 _ 10_3 mm. Compute Poisson’s ratio for this material if its modulus of elasticity is 140 GPa .7.17 A cylindrical specimen of a hypothetical metal alloy is stressed in compression.If its original and final diameters are 20.000 and 20.025 mm, respectively, and its final length is 74.96 mm, compute its original length if the deformation is totally elastic. The elastic and shear moduli for this alloy are 105 Gpa and 39.7 GPa,respectively.7.19 A brass alloy is known to have a yield strength of 275 MPa, a tensile strength of380 MPa, and an elastic modulus of 103 GPa . A cylindrical specimen of thisalloy 12.7 mm in diameter and 250 mm long is stressed in tension and found to elongate 7.6 mm . On the basis of the information given, is it possible tocompute the magnitude of the load that is necessary to produce this change inlength? If so, calculate the load. If not, explain why.7.20A cylindrical metal specimen 15.0mmin diameter and 150mm long is to besubjected to a tensile stress of 50 Mpa; at this stress level the resulting deformation will be totally elastic.(a)If the elongation must be less than 0.072mm,which of the metals in Tabla7.1are suitable candidates? Why ?(b)If, in addition, the maximum permissible diameter decrease is 2.3×10-3mm,which of the metals in Table 7.1may be used ? Why?7.22 Cite the primary differences between elastic, anelastic, and plastic deformationbehaviors.7.23 diameter of 10.0 mm is to be deformed using a tensile load of 27,500 N. It mustnot experience either plastic deformation or a diameter reduction of more than7.5×10-3 mm. Of the materials listed as follows, which are possible candidates?Justify your choice(s).7.24 A cylindrical rod 380 mm long, having a diameter of 10.0 mm, is to besubjected to a tensile load. If the rod is to experience neither plastic deformationnor an elongation of more than 0.9 mm when the applied load is 24,500 N,which of the four metals or alloys listed below are possible candidates?7.25 Figure 7.33 shows the tensile engineering stress–strain behavior for a steel alloy.(a) What is the modulus of elasticity?(b) What is the proportional limit?(c) What is the yield strength at a strain offset of 0.002?(d) What is the tensile strength?7.27 A load of 44,500 N is applied to a cylindrical specimen of steel (displaying thestress–strain behavior shown in Figure 7.33) that has a cross-sectional diameter of 10 mm .(a) Will the specimen experience elastic or plastic deformation? Why?(b) If the original specimen length is 500 mm), how much will it increase inlength when t his load is applied?7.29 A cylindrical specimen of aluminumhaving a diameter of 12.8 mm and a gaugelength of 50.800 mm is pulled in tension. Usethe load–elongation characteristics tabulatedbelow to complete problems a through f.(a)Plot the data as engineering stressversusengineering strain.(b) Compute the modulus of elasticity.(c) Determine the yield strength at astrainoffset of 0.002.(d) Determine the tensile strength of thisalloy.(e) What is the approximate ductility, in percent elongation?(f ) Compute the modulus of resilience.7.35 (a) Make a schematic plot showing the tensile true stress–strain behavior for atypical metal alloy.(b) Superimpose on this plot a schematic curve for the compressive truestress–strain behavior for the same alloy. Explain any difference between thiscurve and the one in part a.(c) Now superimpose a schematic curve for the compressive engineeringstress–strain behavior for this same alloy, and explain any difference between this curve and the one in part b.7.39 A tensile test is performed on a metal specimen, and it is found that a true plasticstrain of 0.20 is produced when a true stress of 575 MPa is applied; for the same metal, the value of K in Equation 7.19 is 860 MPa. Calculate the true strain that results from the application of a true stress of 600 Mpa.7.40 For some metal alloy, a true stress of 415 MPa produces a plastic true strain of0.475. How much will a specimen of this material elongate when a true stress of325 MPa is applied if the original length is 300 mm ? Assume a value of 0.25 for the strain-hardening exponent n.7.43 Find the toughness (or energy to cause fracture) for a metal that experiences bothelastic and plastic deformation. Assume Equation 7.5 for elastic deformation,that the modulus of elasticity is 172 GPa , and that elastic deformation terminates at a strain of 0.01. For plastic deformation, assume that the relationship between stress and strain is described by Equation 7.19, in which the values for K and n are 6900 Mpa and 0.30, respectively. Furthermore, plastic deformation occurs between strain values of 0.01 and 0.75, at which point fracture occurs.7.47 A steel specimen having a rectangular cross section of dimensions 19 mm×3.2mm (0.75in×0.125in.) has the stress–strain behavior shown in Figure 7.33. If this specimen is subjected to a tensile force of 33,400 N (7,500lbf ), then(a) Determine the elastic and plastic strain values.(b) If its original length is 460 mm (18 in.), what will be its final length after theload in part a is applied and then released?7.50 A three-point bending test was performed on an aluminum oxide specimenhaving a circular cross section of radius 3.5 mm; the specimen fractured at a load of 950 N when the distance between the support points was 50 mm . Another test is to be performed on a specimen of this same material, but one that has a square cross section of 12 mm length on each edge. At what load would you expect this specimen to fracture if the support point separation is 40 mm ?7.51 (a) A three-point transverse bending test is conducted on a cylindrical specimenof aluminum oxide having a reported flexural strength of 390 MPa . If the speci- men radius is 2.5 mm and the support point separation distance is 30 mm ,predict whether or not you would expect the specimen to fracture when a load of 620 N is applied. Justify your prediction.(b) Would you be 100% certain of the prediction in part a? Why or why not?7.57 When citing the ductility as percent elongation for semicrystalline polymers, it isnot necessary to specify the specimen gauge length, as is the case with metals.Why is this so?7.66 Using the data represented in Figure 7.31, specify equations relating tensilestrength and Brinell hardness for brass and nodular cast iron, similar toEquations 7.25a and 7.25b for steels.8.4 For each of edge, screw, and mixed dislocations, cite the relationship between thedirection of the applied shear stress and the direction of dislocation line motion.8.5 (a) Define a slip system.(b) Do all metals have the same slip system? Why or why not?8.7. One slip system for theBCCcrystal structure is _110__111_. In a manner similarto Figure 8.6b sketch a _110_-type plane for the BCC structure, representingatom positions with circles. Now, using arrows, indicate two different _111_ slip directions within this plane.8.15* List four major differences between deformation by twinning and deformationby slip relative to mechanism, conditions of occurrence, and final result.8.18 Describe in your own words the three strengthening mechanisms discussed inthis chapter (i.e., grain size reduction, solid solution strengthening, and strainhardening). Be sure to explain how dislocations are involved in each of thestrengthening techniques.8.19 (a) From the plot of yield strength versus (grain diameter)_1/2 for a 70 Cu–30 Zncartridge brass, Figure 8.15, determine values for the constants _0 and ky inEquation 8.5.(b) Now predict the yield strength of this alloy when the average grain diameteris 1.0 _ 10_3 mm.8.20. The lower yield point for an iron that has an average grain diameter of 5 _ 10_2mm is 135 MPa . At a grain diameter of 8 _ 10_3 mm, the yield point increases to 260MPa. At what grain diameter will the lower yield point be 205 Mpa ?8.24 (a) Show, for a tensile test, thatif there is no change in specimen volume during the deformation process (i.e., A0 l0 _Ad ld).(b) Using the result of part a, compute the percent cold work experienced bynaval brass (the stress–strain behavior of which is shown in Figure 7.12) when a stress of 400 MPa is applied.8.25 Two previously undeformed cylindrical specimens of an alloy are to be strainhardened by reducing their cross-sectional areas (while maintaining their circular cross sections). For one specimen, the initial and deformed radii are 16 mm and11 mm, respectively. The second specimen, with an initial radius of 12 mm, musthave the same deformed hardness as the first specimen; compute the secondspecimen’s radius after deformation.8.26 Two previously undeformed specimens of the same metal are to be plasticallydeformed by reducing their cross-sectional areas. One has a circular cross section, and the other is rectangular is to remain as such. Their original and deformeddimensions are as follows:Which of these specimens will be the hardest after plastic deformation, and why?8.27 A cylindrical specimen of cold-worked copper has a ductility (%EL) of 25%. Ifits coldworked radius is 10 mm (0.40 in.), what was its radius beforedeformation?8.28 (a) What is the approximate ductility (%EL) of a brass that has a yield strengthof 275 MPa ?(b) What is the approximate Brinell hardness of a 1040 steel having a yieldstrength of 690 MPa?8.41 In your own words, describe the mechanisms by which semicrystalline polymers(a) elasticallydeform and (b) plastically deform, and (c) by which elastomerselastically deform.8.42 Briefly explain how each of the following influences the tensile modulus of asemicrystallinepolymer and why:(a) molecular weight;(b) degree of crystallinity;(c) deformation by drawing;(d) annealing of an undeformed material;(e) annealing of a drawn material.8.43* Briefly explain how each of the following influences the tensile or yieldstrength of a semicrystalline polymer and why:(a) molecular weight;。
Creativity The Ultimate Weapon
Creativity The Ultimate Weapon Creativity has always been considered a powerful tool, but in today's fast-paced and ever-changing world, it has become the ultimate weapon. With the rise of technology and automation, many traditional jobs are being replaced by machines, and the demand for creative thinkers is higher than ever. In this essay, we will explore the various ways in which creativity can be used as a weapon, from the individual level to global scale, and how it can be harnessed to solve some of the world's most pressing issues. At the individual level, creativity can be a powerful weapon for personal growth and success. In a world where conformity and following the rules are often rewarded, those who think outside the box and comeup with innovative solutions are the ones who stand out. Creativity allows individuals to see problems from different perspectives, come up with unique solutions, and adapt to new challenges. It enables them to break free from the constraints of traditional thinking and carve their own path to success. Moreover, creativity is not just about artistic expression; it is also about problem-solving and innovation. In today's highly competitive job market, employers are lookingfor individuals who can bring fresh ideas and creative solutions to the table. By harnessing their creativity, individuals can set themselves apart from the competition and thrive in their careers. It allows them to adapt to new technologies and industries, and to continuously learn and grow in their professional lives. On a societal level, creativity can be used as a weapon to drive positive change and address pressing issues. From climate change to social inequality, many of the world's most complex problems require innovative and creative solutions. By thinking creatively, individuals and organizations can develop new technologies, business models, and policies that can help mitigate these issues. Creativity can also be used to inspire and mobilize people to take action, whether it's through art, music, or storytelling. Furthermore, creativity can be a powerful force for social and cultural change. Through creative expression, individuals can challenge existing norms and beliefs, and advocate for new ways of thinking and living. Whether it's through literature, film, or visual arts, creativity has the power to spark important conversations and shape the way people perceive the world around them. It can also be used to preserve andcelebrate diverse cultures, traditions, and histories, ensuring that they are not lost or forgotten. At a global level, creativity can be used as a weapon tofoster collaboration and diplomacy. In a world that is often divided by political, cultural, and economic differences, creativity has the power to bring people together. Whether it's through international art exhibitions, cultural exchanges, or collaborative projects, creativity can bridge the gap between nations andfoster understanding and empathy. It can also be used to address global challenges such as poverty, conflict, and disease, by bringing together diverse perspectives and expertise to find innovative solutions. In conclusion, creativity is indeed the ultimate weapon, with the power to drive personal growth, foster innovation, drive social change, and promote global collaboration. It is a tool that can be harnessed by individuals, organizations, and nations to address some of the most pressing issues of our time. By embracing and nurturing creativity, we can unlock new possibilities and create a better future for ourselves and the world.。
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a rXiv:q uant-ph/06547v14M ay26New experimental limit on the Pauli Exclusion Principle violation by electrons The VIP Collaboration:S.Bartalucci a ,S.Bertolucci a ,M.Bragadireanu a ,b ,M.Cargnelli c ,M.Catitti a ,C.Curceanu (Petrascu)a ,∗,S.Di Matteo a ,J.-P.Egger d ,C.Guaraldo a ,M.Iliescu a ,b ,T.Ishiwatari c ,ubenstein e ,J.Marton c ,otti f ,D.Pietreanu a ,T.Ponta b ,D.L.Sirghi a ,b ,F.Sirghi a ,b ,L.Sperandio a ,E.Widmann c ,J.Zmeskal c a INFN,Laboratori Nazionali di Frascati,C.P.13,Via E.Fermi 40,I-00044,Frascati (Roma),Italy b ’Horia Hulubei’National Institute of Physics and Nuclear Engineering,Str.Atomistilor no.407,P.O.Box MG-6,Bucharest -Magurele,Romania c Stefan Meyer Institute for Subatomic Physics,Boltzmanngasse 3,A-1090Vienna,Austria d Institute de Physique,Universit´e de Neuchˆa tel,1rue A.-L.Breguet,CH-2000Neuchˆa tel,Switzerland e Laboratori Nazionali del Gran Sasso,S.S.17/bis,I-67010Assergi (AQ),Italy f Dipartimento di Fisica,Universit`a di Trieste and INFN–Sezione di Trieste,Via Valerio,2,I-34127Trieste,Italy2β2≤4.5×10−28,improves the existing limit byalmost two orders of magnitude.Key words:symmetrization principle,identical particles,tests of quantum field theories,anomalous atomic transitions,X rays,CCDPACS:11.30.-j;03.65.-w;29.30.Kv;32.30.Rj1IntroductionThe Pauli Exclusion Principle(PEP)is a consequence of the spin-statistics connection[1]and plays a fundamental role in our understanding of many physical and chemical phenomena,from the periodic table of elements,to the electric conductivity in metals,to the degeneracy pressure,which makes white dwarfs and neutron stars stable,just to cite few ones.Although the principle has been spectacularly confirmed by the number and accuracy of its predictions,its foundation lies deep in the structure of quantumfield theory and has defied all attempts to produce a simple proof,as nicely stressed by R.Feynman[2].Given its basic standing in quantum theory,it seems appropriate to carry out precise tests of the PEP validity and,indeed,in the lastfifty years,sev-eral experiments have been performed to search for possible small violations [3,4,5,6,7,8].Often,these experiments were born as by-products of experiments with a different objective(e.g.dark matter searches,proton decay,etc..),and most of the recent limits on the validity of PEP have been obtained for nuclei or nucleons.Concerning the violation of PEP for electrons,Greenberg and Mohapatra[9] examined all experimental data which could be related,directly or indirectly, to PEP,up to1987.In their analysis they concluded that the probability that a new electron added to an antisymmetric collection of N electrons might form a mixed symmetry state rather than a totally antisymmetric state is≤10−9.In 1988,Ramberg and Snow[10]drastically improved this limit with a dedicated experiment,searching for anomalous X-ray transitions,that would point to a small violation of PEP in a copper conductor.The result of the experiment was a probability≤1.7×10−26that a new electron circulating in the conductor would form a mixed symmetry state with the already present copper electrons. We have set up an improved version of the Ramberg and Snow experiment, with a higher sensitivity apparatus[11].Ourfinal aim is to lower the PEP violation limit for electrons by at least4orders of magnitude,by using high resolution Charge-Coupled Devices(CCD)as soft X-rays detectors[12],and decreasing the effect of background by a careful choice of the materials and sheltering the apparatus in an underground laboratory.In the next sections we describe the experimental setup,the outcome of a pre-liminary measurement performed in the Frascati National Laboratories(LNF) of INFN in2005,along with a brief discussion on the results and the foreseen future improvements in the Gran Sasso National Laboratory(LNGS)of INFN.2The VIP experimentThe idea of the VIP(V auli Exclusion Principle)experiment was originated by the availability of the DEAR(DAΦNE Exotic Atom Re-search)setup,after it had successfully completed its program at the DAΦNE collider at LNF-INFN[13].DEAR used Charge-Coupled Devices(CCD)as de-tectors in order to measure exotic atoms(kaonic nitrogen and kaonic hydrogen) X-ray D’s are almost ideal detectors for X-rays measurement, due to their excellent background rejection capability,based on pattern recog-nition,and to their good energy resolution(320eV FWHM at8keV in the present measurement).2.1Experimental methodThe experimental method,originally described in[10],consists in the intro-duction of new electrons into a copper strip,by circulating a current,and in the search for X rays resulting from the2p→1s anomalous radiative transi-tion that occurs if one of the new electrons is captured by a copper atom and cascades down to the1s state alreadyfilled by two electrons of opposite spin. The energy of this transition would differ from the normal Kαtransition by about300eV(7.729keV instead of8.040keV)[14],providing an unambigu-ous signal of the PEP violation.The measurement alternates periods without current in the copper strip,in order to evaluate the X-ray background in conditions where no PEP violating transitions are expected to occur,with pe-riods in which currentflows in the conductor,thus providing“fresh”electrons, which might possibly violate PEP.The fact that no PEP violating transitions are expected to be present in the measurement without current is related to the consideration that any initial conduction electron in the copper that was in a mixed symmetry state with respect to the other copper electrons,would have already cascaded down to the1s state and would therefore be irrelevant for the present experiment.The rather straightforward analysis consists in the evaluation of the statistical significance of the normalized subtraction of the two spectra,with and without current,in the energy region where the PEP violating transition is expected.2.2The VIP setupThe VIP setup consists of a copper cylinder,4.5cm in radius,50µm thick,8.8cm high,surrounded by16equally spaced CCD’s[15].The CCD’s are ata distance of2.3cm from the copper cylinder,grouped in units of two chips vertically positioned.The setup is shown in Fig.1.The chamber is kept atFig.1.The VIP setup.All elements af the setup are identified in thefigure.high vacuum to minimize X-ray absorption and to avoid condensation on the cold surfaces.The copper target(the copper strip where the currentflows and new electrons are injected from the power supply)is at the bottom of the setup.The CCD’s surround the target and are supported by coolingfingers that start from the cooling heads in the upper part of the chamber.The CCD readout electronics is just behind the coolingfingers;the signals are sent to amplifiers on the top of the chamber.The amplified signals are read out by ADC boards in a data acquisition computer.More details on the CCD-55performance,as well as on the analysis method used to reject background,can be found in[16]2.3MeasurementsThe measurements reported in this paper have been performed in the period 21November-13December2005,at the Frascati National Laboratories ofINFN,Italy.X-ray energy (keV)C o u n t s /30 eV X-ray energy (keV)Fig.2.Energy spectra for the VIP measurements:a)with current (I=40A);b)without current (I=0).Two types of measurements were performed:•14510minutes (about 10days)of measurements with a 40A current circu-lating in the copper target;•14510minutes of measurements without circulating current,where CCD’s were read-out every 10minutes.The two resulting X-ray spectra are shown in Figure 2a),with circulating current,and b),without current.The spectra refer to 14CCD’s (out of 16),due to noise problems in the remaining 2.3PEP-violating X-ray spectrumIn order to obtain the number of X-rays due to the possible PEP violating transitions,the spectrum without current was subtracted from the one with current.The resulting subtracted spectrum is shown in Figure 3a)(whole energy scale)and b)(a zoom on the region of interest).The region of interest,from 7.564to7.894keV,is defined by the CCD energy resolution (320eV FWHM)at the K αcopper transition (8.04keV),with an additional uncertainty of 10eV,to account for the theoretical uncertainty in the calculation of the PEP violating transition energy.The numbers of X rays in the region of interest were:X-ray energy (keV)X-ray energy (keV) Fig.3.The subtracted spectrum:current minus no-current,giving the limit on PEP violation for electrons:a)whole energy range;b)expanded view in the region of interest(7.564-7.894keV).No evidence for a peak in the region of interest is found.•at I=40A:N X=2721±52;•for I=0A:N X=2742±52;•for the subtracted spectrum:∆N X=−21±73.3.1Determination of the PEP violation probability limitFor the parametrization of the results in a Pauli principle violating theory,we use the notation of Ignatiev and Kuzmin[17],which has been incorporated in the paper of Greenberg and Mohapatra[9]:even though the model of Ignatiev and Kuzmin has been later shown to be incompatible with quantumfield theory[18],the parameterβthat measures the degree of PEP violation has stuck and is still found in the literature,also because it is easy to show that it is related to the parameter q of quon theory,by the relation:(1+q)/2=β2/2 [19](in quon theory,−1≤q≤1,where q=−1corresponds to fermions and q=1corresponds to bosons,so that here q must be close to-1and(1+q)/2 must be very small,because we are dealing with electrons).Moreover,we used this parametrization for an easy comparison of our results with the previous Ramberg and Snow ones[10],since the same has been used in that paper.In [17]a pair of electrons in a mixed symmetry state has the probabilityβ2/2 for the symmetric component and(1−β2/2)for the usual antysymmetric one.The parameterβ2/2is related,then,to the probability that an electron violates PEP(see also[20]for further details).To determine the experimentallimit onβ2/2from our data,we used the same arguments of Ramberg and Snow,to compare the results.The number of electrons that pass through the conductor,which are new for this conductor,is:N new=(1/e)ΣI∆t.(1) where e is the electron electric charge,I is the current intensity and∆t repre-sents the time duration of the measurement with current on.Each new electron will undergo a large number of scattering processes on the atoms of the cop-per lattice.The minimum number of these internal scattering processes per electron,defined as N int,is of order D/µ,where D is the length of the copper electrode(8.8cm in our case)andµis the mean free path of electrons in copper.The latter parameter is obtained from the resistivity of the metal.We assume that the capture probability(aside from the factor∼β2/2)is greater than12β2N new1eµ12.(3)The difference of events between the measurements with and without current, reported in the previous Section,is∆N X=−21±73.Taking as a limit of observation three standard deviations,we get for the PEP violating parameter:β24.9×1029=4.5×10−28at99.7%CL.(4)We can interpret this as a limit on the probability of PEP violating interactions between external electrons and copper atoms:12β2≤4.5×10−28,lowering by almost two orders ofmagnitude the previous one[10].We shall soon repeat the measurement in the Gran Sasso–INFN underground laboratory,at higher integrated currents.From preliminary tests,it appears that the X-ray background in the LNGS environment is a factor10-100lower than in the Frascati Laboratories.A VIP measurement of two years(one with current,one without current)at LNGS,to start in Spring2006,will then bring the limit on PEP violation for electrons into the10−30-10−31region,which is of particular interest[21]for all those theories related to possible PEP violation coming from new physics.References[1]W.Pauli,Phys.Rev.58(1940)716.[2]R.P.Feynman,R.B.Leighton,and M.Sands:”The Feynman Lectures onPhysics”,vol.3,(Addison-Wesley,Reading,MA,1963).[3]R.Bernabei et al.,Phys.Lett.B408(1997)439.[4]H.O.Back et al.(Borexino Collaboration),Eur.Phys.J.C37(2004)421.[5]R.C.Hilborn and C.L.Yuca,Phys.Rev.Lett.76(1996)2844.[6]NEMO Collaboration,Nucl.Phys.B87(Proc.Suppl.)(2000)510.[7] E.Nolte et al.,J.Phys.G:Nucl.Part.Phys.17(1991)S355.[8]Yu.M.Tsipenyuk,A.S.Barabash,V.N.Kornoukhov,and B.A.Chapyzhnikov,Radiat.Phys.Chem.51(1998)507.[9]O.W.Greenberg and R.N.Mohapatra,Phys.Rev.Lett.59(1987)2507.[10]E.Ramberg and G.A.Snow,Phys.Lett.B238(1990)438.[11]The VIP Proposal,LNF-LNGS Proposal,September2004(http://www.lnf.infn.it/esperimenti/vip).[12]See e.g.J.L.Culhane,Nucl.Instr.and Meth.A310(1991)1;J.-P.Egger,D.Chatellard,E.Jeannet,Particle World3(1993)139;G.Fiorucci et al.,Nucl.Instr.and Meth.A292(1990)141;D.Varidel et al.,Nucl.Instr.and Meth.A292(1990)147;R.P.Kraft et al.,Nucl.Instr.and 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