Nucleat physics of core collapse supernova

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Periphery deformations and tunneling at correlated quantum-Hall edges

In this article, we propose an explanation for the experimental results which is based on two key observations. First, at ﬁlling factors ν < 1, strong and subtle correlations exist in the bulk of a 2D electron gas, even when it is compressible. Tunneling at low energies is extremely strongly suppressed because states with an uncorrelated electron inserted or removed are nearly orthogonal to the low-energy states in which all electrons are strongly correlated.16 This property is established by bulk 2D-2D tunneling experiments17 which manifest a wide gap in the TDOS at all values of ν. Like their edge counterparts, bulk-TDOS results exhibit surprisingly little dependence on the occurrence or absence of the quantum Hall eﬀect. Second, in any ﬁnite quantum-Hall system, there exists a series of low-energy excitations which are generated by electronically rigid deformations of the system periphery. We will refer to these as periphery-deformation (PD) excitations. We propose that in systems where the conﬁning potential is smooth enough that electrons remain strongly correlated at the edge, tunneling electrons can be accommodated, at low energies, only by periphery deformations. In the following, we explain why PD excitations are generic, and establish the properties underlying the edge-TDOS observations.

我奇怪的想法英文作文

我奇怪的想法英文作文The Curious Mind: A Journey Through Unusual Thoughts.In the vast expanse of the universe, our minds are tiny islands floating on a sea of infinity. They are the repositories of our thoughts, dreams, and imaginations, and sometimes, they are the birthplaces of strange and unusual ideas. These ideas, often labeled as "weird" or "strange" by society, are actually the most fascinating aspects of our existence. They push the boundaries of our understanding, challenge our perceptions, and force us to question the world we know.For me, one such strange idea has always fascinated me: the concept of parallel universes. The idea that there could be an infinite number of worlds, each with its own laws of physics, history, and culture, is mind-boggling. What if, somewhere out there, there is a universe where gravity works in reverse, or where the sun shines at night? Or perhaps a universe where history unfolded differently,and the outcomes of major events were entirely different?The concept of parallel universes is not just a figment of my imagination; it has been explored by physicists, philosophers, and writers alike. The idea gained popularity in the 20th century with the development of quantum physics, which suggested that the universe might be made up of multiple realities that coexist simultaneously. This theory, known as the Many-Worlds Interpretation, proposed thatevery possible outcome of a quantum event occurs in a separate universe.While the scientific community is still debating the validity of this theory, it has sparked a wave ofcreativity among writers and artists. It has given us a platform to explore the limitless possibilities ofexistence and to imagine worlds that are entirely different from our own. Novels, movies, and TV shows have beeninspired by the concept of parallel universes, allowing usto escape the confines of our reality and immerse ourselves in exciting new worlds.Another strange idea that intrigues me is the concept of time travel. The idea that we could travel through time, visit the past or future, has fascinated humans for centuries. From the time-traveling heroes of sciencefiction novels to the philosophical debates about the nature of time, this concept has always captivated our imaginations.The possibility of time travel raises a number of fascinating questions. Could we change the course ofhistory by interfering with past events? Would we even be able to recognize the future if we saw it? And what wouldit mean to travel through time and find ourselves in a world that is entirely different from the one we left?These are questions that science has yet to answer, but they are questions that continue to inspire us to push the boundaries of our understanding. The concept of time travel may never become a reality, but it remains a powerful tool for exploring our understanding of the universe and our place within it.In conclusion, strange ideas are not just figments of our imaginations; they are windows to a world beyond our comprehension. They challenge our perceptions, push the boundaries of our understanding, and inspire us to question everything we know. Whether it's the concept of parallel universes or the possibility of time travel, these ideas force us to reevaluate our understanding of the world and our place within it. As we continue to explore the vast expanse of the universe and the infinite possibilities of our minds, these strange ideas will continue to guide us on our journey through existence.。

新的125个科学问题

新的125个科学问题2005年，在庆祝创刊125周年之际，Science公布了125个最具挑战性的科学问题，对指引近十几年的科学发展产生积极影响。

16年之后的2021年，随着科学的不断突破，许多问题得到一定程度的解答，一些问题也更加深入。

彼时，上海交通大学携手Science 杂志发布了“新125个科学问题”——《125个科学问题：探索与发现》。

此次发布的问题包括数学、化学、医学与健康、生命科学、天文学、物理学、信息科学、工程与材料科学、神经科学、生态学、能源科学与人工智能等领域。

除了“物质的起源是什么”“黎曼猜想是真的吗”“地球上有多少物种”等科学家始终在追问的问题，还有一些有趣的问题也将带来面向人类未来的科学探究，例如：为什么我们会坠入爱河？人类有一天会不得不离开地球吗？人类为什么会对猫狗如此着迷？此次科学问题征集结合国际前沿、全球共需、科学发展，聚焦前瞻重大科学问题，面向科学家、学生、社会征集。

世界顶尖科学家协会也发挥资源优势，邀请诺贝尔奖、沃尔夫奖、拉斯克奖、图灵奖、麦克阿瑟天才奖等世界“最强大脑”共同参与，共同讨论人类当前与未来面对的科学问题。

SJTU & Science 125个科学问题Mathematical Sciences数学1. What makes prime numbers so special?1.什么使素数如此特别？2. Will the Navier–Stokes problem ever be solved?2.纳维尔-斯托克斯问题会得到解决吗？3. Is the Riemann hypothesis true?3.黎曼猜想是真的吗？Chemistry1. Are there more color pigments to discover?1.还有更多色彩元素可发现吗？2. Will the periodic table ever be complete?2.元素周期表会完整吗？3. How can we measure interface phenomena on the microscopic level?3.如何在微观层面测量界面现象？4. What is the future for energy storage？4.能量存储的未来是怎样的？5. Why does life require chirality?5.为什么生命需要手性？6. How can we better manage the world's plastic waste?6.我们如何更好地管理世界上的塑料废物？7. Will AI redefine the future of chemistry?7.AI会重新定义化学的未来吗？8. How can matter be programmed into living materials?8.物质如何被编码而成为生命材料？9. What drives reproduction in living systems?9.是什么驱动生命系统的复制？Medicine & Health医学与健康1. Can we predict the next pandemic?1.我们可以预测下一次流行病吗？2. Will we ever find a cure for the common cold?2.我们会找到治疗感冒的方法吗？3. Can we design and manufacture medicines customized for individual people?3.我们可以设计和制造出为个人定制的药物吗？4. Can a human tissue or organ be fully regenerated?4.人体组织或器官可以完全再生吗？5. How is immune homeostasis maintained and regulated?5.如何维持和调节免疫稳态？6. Is there a scientific basis to the Meridian System in traditional Chinese medicine?6.中医的经络系统有科学依据吗？7. How will the next generation of vaccines be made?7.下一代疫苗将如何生产？8. Can we ever overcome antibiotic resistance?8.我们能否克服抗生素耐药性？9. What is the etiology of autism?9.自闭症的病因是什么？10. What role does our microbiome play in health and disease?10.我们的微生物组在健康和疾病中扮演什么角色？11. Can xenotransplantation solve the shortage of donor organs?11.异种移植能否解决供体器官的短缺问题？Biology生命科学1. What could help conservation of the oceans?1.什么可以帮助保护海洋？2. Can we stop ourselves from aging?2.我们可以阻止自己衰老吗？3. Why can only some cells become other cells?3.为什么只有一些细胞会变成其他细胞？4. Why are some genomes so big and others very small?4.为什么有些基因组非常大而另一些却很小？5. Will it be possible to cure all cancers?5.有可能治愈所有癌症吗？6. What genes make us uniquely human?6.哪些基因使我们人类与众不同？7. How do migratory animals know where they're going?7.迁徙动物如何知道它们要去哪里？8. How many species are there on Earth?8.地球上有多少物种？9. How do organisms evolve?9.有机体是如何进化的？10. Why did dinosaurs grow to be so big?10.为什么恐龙长得如此之大？11. Did ancient humans interbreed with other human-like ancestors?11.远古人类是否曾与其他类人祖先杂交？12. Why do humans get so attached to dogs and cats?12.人类为什么会对猫狗如此着迷？13. Will the world's population keep growing indefinitely?13.世界人口会无限增长吗？14. Why do we stop growing?14.我们为什么会停止生长？15. Is de-extinction possible?15.能否复活灭绝生物？16. Can humans hibernate?16.人类可以冬眠吗？17. Where do human emotions originate?17.人类的情感源于何处？18. Will humans look physically different in the future?18.未来人类的外貌会有所不同吗？19. Why were there species explosions and mass extinction?19.为什么会发生物种大爆发和大灭绝？20. How might genome editing be used to cure disease?20.基因组编辑将如何用于治疗疾病？21. Can a cell be artificially synthesized?21.可以人工合成细胞吗？22. How are biomolecules organized in cells to function orderly and effectively?22.细胞内的生物分子是如何组织从而有序有效发挥作用的？Astronomy天文学1. How many dimensions are there in space?1.空间中有多少个维度？2. What is the shape of the universe?2.宇宙的形状是怎样的？3. Where did the big bang start?3.大爆炸从何处开始？4. Why don't the orbits of planets decay and cause them to crash into each other?4.为什么行星的轨道不衰减并导致它们相互碰撞？5. When will the universe die? Will it continue to expand?5.宇宙何时消亡？它会继续膨胀吗？6. Is it possible to live permanently on another planet?6.我们有可能在另一个星球上长期居住吗？7. Why do black holes exist?7.为什么存在黑洞？8. What is the universe made of?8.宇宙是由什么构成的？9. Are we alone in the universe?9.我们是宇宙中唯一的生命体吗？10. What is the origin of cosmic rays?10.宇宙射线的起源是什么？11. What is the origin of mass?11.物质的起源是什么？12. What is the smallest scale of space-time?12.时空的最小尺度是是多少？13. Is water necessary for all life in the universe, or just on Earth?13.水是宇宙中所有生命所必需的么，还是仅对地球生命？14. What is preventing humans from carrying out deep-space exploration?14.是什么阻止了人类进行深空探测？15. Is Einstein's general theory of relativity correct?15.爱因斯坦的广义相对论是正确的吗？16. How are pulsars formed?16.脉冲星是如何形成的？17. Is our Milky Way Galaxy special?17.我们的银河系特别吗？18. What is the volume, composition, and significance of the deep biosphere?18.深层生物圈的规模、组成和意义是什么？19. Will humans one day have to leave the planet (or die trying)?19.人类有一天会不得不离开地球吗（还是会在尝试中死去）？20. Where do the heavy elements in the universe come from?20.宇宙中的重元素来自何处？21. Is it possible to understand the structure of compact stars and matter?21.有可能了解致密恒星和物质的结构吗？22. What is the origin of the high-energy cosmic neutrinos?22.高能宇宙中微子的起源是什么？23. What is gravity?23.什么是重力？Physics物理学1. Is there a diffraction limit?1.有衍射极限吗？2. What is the microscopic mechanism for high-temperature superconductivity?2.高温超导的微观机理是什么？3. What are the limits of heat transfer in matter?3.物质传热的极限是什么？4. What are the fundamental principles of collective motion?4.集体运动的基本原理是什么？5. What are the smallest building blocks of matter?5.什么是物质的最小组成部分？6. Will we ever travel at the speed of light?6.我们会以光速行驶吗？7. What is quantum uncertainty and why is it important?7.什么是量子不确定性，为什么它很重要？8. Will there ever be a "theory of everything"?8.会有“万有理论”吗？9. Why does time seem to flow in only one direction?9.为什么时间似乎只朝一个方向流动？10. What is dark matter?10.什么是暗物质？11. Can we make a real, human-size invisibility cloak?11.我们可以制作出真人大小的隐形斗篷吗？12. Are there any particles that behave oppositely to the properties or states of photons?12.是否存在与光子性质或状态相反的粒子？13. Will the Bose-Einstein condensate be widely used in the future?13.玻色-爱因斯坦冷凝体未来会被广泛使用吗？14. Can humans make intense lasers with incoherence comparable to sunlight?14.人类能制造出与太阳光相似的非相干强激光吗？15. What is the maximum speed to which we can acceleratea particle?15.我们最多可以将粒子加速到多快？16. Is quantum many-body entanglement more fundamental than quantum fields?16.量子多体纠缠比量子场更基本吗？17. What is the optimum hardware for quantum computers?17.量子计算机的最佳硬件是什么？18. Can we accurately simulate the macro- and microworld?18.我们可以精确模拟宏观和微观世界吗？Information Science信息科学1. Is there an upper limit to computer processing speed?1.计算机处理速度是否有上限？2. Can AI replace a doctor?2.AI可以代替医生吗？3. Can topological quantum computing be realized?3.拓扑量子计算可以实现吗？4. Can DNA act as an information storage medium?4.DNA可以用作信息存储介质吗？Engineering & Material Science工程与材料科学1. What is the ultimate statistical invariances of turbulence?1.湍流的最终统计不变性是什么？2. How can we break the current limit of energy conversion efficiencies?2.我们如何突破当前的能量转换效率极限？3. How can we develop manufacturing systems on Mars?3.我们如何在火星上开发制造系统？4. Is a future of only self-driving cars realistic?4.纯无人驾驶汽车的未来是否现实？Neuroscience神经科学1. What are the coding principles embedded in neuronal spike trains?1.神经元放电序列的编码准则是什么？2. Where does consciousness lie?2.意识存在于何处？3. Can human memory be stored, manipulated, and transplanted digitally?3.能否数字化地存储、操控和移植人类记忆？4. Why do we need sleep?4.为什么我们需要睡眠？5. What is addiction and how does it work?5.什么是成瘾？6. Why do we fall in love?6.为什么我们会坠入爱河？7. How did speech evolve and what parts of the brain control it?7.言语如何演变形成，大脑的哪些部分对其进行控制？8. How smart are nonhuman animals?8.除人类以外的其他动物有多聪明？9. Why are most people right-handed?9.为什么大多数人都是右撇子？10. Can we cure neurodegenerative diseases?10.我们可以治愈神经退行性疾病吗？11. Is it possible to predict the future?11.有可能预知未来吗？12. Can we more effectively diagnose and treat complex mental disorders?12.精神障碍能否有效诊断和治疗？Ecology生态学1. Can we stop global climate change?1.我们可以阻止全球气候变化吗？2. Where do we put all the excess carbon dioxide?2.我们能把过量的二氧化碳存到何处？3. What creates the Earth's magnetic field (and why does it move)?3.是什么创造了地球的磁场（为什么它会移动）？4. Will we be able to predict catastrophic weather events (tsunami, hurricanes, earthquakes) more accurately?4.我们是否能够更准确地预测灾害性事件（海啸、飓风、地震）？5. What happens if all the ice on the planet melts?5.如果地球上所有的冰融化会怎样？6. Can we create an environmentally friendly replacement for plastics?6.我们可以创造一种环保的塑料替代品吗？7. Can we achieve a situation where essentially every material can be recycled and reused?7.几乎所有材料都可以回收再利用是否可以实现？8. Will we soon see the end of monocultures like wheat, maize, rice, and soy?8.我们会很快看到小麦、玉米、大米和大豆等单一作物的终结吗？Energy Science能源科学1. Could we live in a fossil-fuel-free world?1.我们可以生活在一个去化石燃料的世界中吗？2. What is the future of hydrogen energy?2.氢能的未来是怎样的？3. Will cold fusion ever be possible?3.冷聚变有可能实现吗？Artificial Intelligence人工智能1. Will injectable, disease-fighting nanobots ever be a reality?1.可注射的抗病纳米机器人会成为现实吗？2. Will it be possible to create sentient robots?2.是否有可能创建有感知力的机器人？3. Is there a limit to human intelligence?3.人类智力是否有极限？4. Will artificial intelligence replace humans?4.人工智能会取代人类吗？5. How does group intelligence emerge?5.群体智能是如何出现的？6. Can robots or AIs have human creativity?6.机器人或 AI 可以具有人类创造力吗？7. Can quantum artificial intelligence imitate the human brain?7.量子人工智能可以模仿人脑吗？8. Could we integrate with computers to form a human-machine hybrid species?8.我们可以和计算机结合以形成人机混合物种吗？。

白矮星中子星与黑洞 White Dwarfs Neutron Stars and Black Holes

Size vs Density
Some Examples
1.0 0.0 -1.0 -2.0 -3.0 -4.0 -5.0 -6.0
Size, Earth Radius
Earth 1/10 Earth No Equation of State Exists in the Universe! NS Las Cruces
Mass really “warps” space and time. Think of space as a two dimensional sheet. A lot of mass in a small area forms a very deep and narrow funnel. The more space is warped, the slower time flows. Deep in the funnel time passes slowly, away from the funnel it passes “normally”.
With all that energy and spinning, surface electrons get stripped out and beam gamma-ray, X-ray, UV, and optical radiation along the star’s poles.
Crab Nebula Pulsar pulses every 0.033 seconds
Black Hole
When the a large mass is confined to a small size, the funnel becomes infinitely deep! The density is so high (greater than 100 trillion times water) that … no form of matter can support itself against the crush of its own space time warp! 2GM Rs = c

Thermal Evolution of Compact Stars

Preprint submitted to Nuclear Physics A
1 February 2008
1
Introduction
A forefront area of research, both experimental and theoretical, concerns the exploration of the properties of matter under extreme conditions of temperature and/or density and the determination of the equation of state (pressure versus density) associated with it. Its knowledge is of key importance for our understanding of the physics of the early universe, its evolution to the present day, compact stars, various astrophysical phenomena, and laboratory physics (for an overview, see, for example, [1]). On the earth, relativistic heavy-ion colliders provide the only tool by means of which such matter can be created and its properties studied. On the other hand, however, it is well known that nature has created a large number of massive stellar objects, i.e., white dwarfs and neutron stars, which contain matter in one of the densest forms found in the universe. Neutron stars are associated with two classes of astrophysical objects – pulsars and compact X-ray sources. Matter in their cores possess densities ranging from a few times the density of normal nuclear matter to about an order of magnitude higher, depending on star mass. To the present day, about 600 pulsars are known, and the discovery rate of new ones is rather high. This is accompanied by an impressive growth rate of the body of observed pulsar data, like pulsar temperatures determined by the X-ray observatories Einstein, EXOSAT, and ROSAT [2–4]. In this paper, we shall apply a broad collection of modern, ﬁeld-theoretical equations of state (EOS) to the study of the cooling behavior of both neutron stars and their strange counterparts – strange matter stars – which should exist if 3-ﬂavor strange quark matter is more stable than conﬁned hadronic matter. This collection of EOSs was derived under numerous model assumptions about the behavior of superdense stellar matter. To mention several are: the many-body technique used to determine the equation of state; the model for the nucleon-nucleon interaction; description of electrically charge neutral neutron star matter in terms of either only neutrons, neutrons and protons in generalized chemical equilibrium (β equilibrium) with electrons and muons, or nucleons, hyperons and more massive baryon states in β equilibrium with leptons; behavior of the hyperon coupling strengths in matter, inclusion of meson (π , K ) condensation; treatment of the transition of conﬁned hadronic matter into quark matter; and assumptions about the true ground state of strongly interacting matter (i.e., absolute stability of strange quark matter relative to baryon matter). The paper is organized as follows. In section 2 we introduce the set of equations that govern the cooling behavior of massive stars. The collection of equations of state for neutron stars is discussed in section 3. The physics of strange stars and their associated EOS is explained in section 4. The phenomenon of superﬂuidity and the various neutrino emission processes are outlined in 2

2022考研英语阅读反物质研究突飞猛进

2022考研英语阅读反物质研究突飞猛进Fundamental physics Antimatter of fact基础物理反物质讨论突飞猛进Researchers at CERN have held on to anti-atoms for a full quarter of an hour欧洲核子讨论中心的科研人员让反原子颗粒存在时间长达15分钟READERS who were paying attention in their maths classes may recall that quadraticequations often have two solutions, one positive and one negative.数学课上仔细听讲的读者伴侣或许都能想起二次方程式通常有两个解:一个是正解,另一个是负解。

So when, in 1928, a British physicist called Paul Dirac solved such an equation relating to theelectron, the fact that one answer described the opposite of that particle might have beenbrushed aside as a curiosity.因此1928年，当英国物理学家保罗狄拉克在解一道有关微观电子的类似方程时，得到了一个描述电子颗粒负状态的结果，该结果根据特别状况本应当予以舍弃，但实际状况并非如此。

But it wasn t. Instead, Dirac interpreted it as antimatter-and, four years later, it turned up ina real experiment.狄拉克把这种负粒子解释为反物质，四年后，反物质在真实的试验中消失。

MIPS芯片架构说明

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All rights reserved.Table of ContentsChapter 1 About This Book (1)1.1 Typographical Conventions (1)1.1.1 Italic Text (1)1.1.2 Bold Text (1)1.1.3 Courier Text (1)1.2 UNPREDICTABLE and UNDEFINED (2)1.2.1 UNPREDICTABLE (2)1.2.2 UNDEFINED (2)1.3 Special Symbols in Pseudocode Notation (2)1.4 For More Information (4)Chapter 2 The MIPS Architecture: An Introduction (7)2.1 MIPS32 and MIPS64 Overview (7)2.1.1 Historical Perspective (7)2.1.2 Architectural Evolution (7)2.1.3 Architectural Changes Relative to the MIPS I through MIPS V Architectures (9)2.2 Compliance and Subsetting (9)2.3 Components of the MIPS Architecture (10)2.3.1 MIPS Instruction Set Architecture (ISA) (10)2.3.2 MIPS Privileged Resource Architecture (PRA) (10)2.3.3 MIPS Application Specific Extensions (ASEs) (10)2.3.4 MIPS User Defined Instructions (UDIs) (11)2.4 Architecture Versus Implementation (11)2.5 Relationship between the MIPS32 and MIPS64 Architectures (11)2.6 Instructions, Sorted by ISA (12)2.6.1 List of MIPS32 Instructions (12)2.6.2 List of MIPS64 Instructions (13)2.7 Pipeline Architecture (13)2.7.1 Pipeline Stages and Execution Rates (13)2.7.2 Parallel Pipeline (14)2.7.3 Superpipeline (14)2.7.4 Superscalar Pipeline (14)2.8 Load/Store Architecture (15)2.9 Programming Model (15)2.9.1 CPU Data Formats (16)2.9.2 FPU Data Formats (16)2.9.3 Coprocessors (CP0-CP3) (16)2.9.4 CPU Registers (16)2.9.5 FPU Registers (18)2.9.6 Byte Ordering and Endianness (21)2.9.7 Memory Access Types (25)2.9.8 Implementation-Specific Access Types (26)2.9.9 Cache Coherence Algorithms and Access Types (26)2.9.10 Mixing Access Types (26)Chapter 3 Application Specific Extensions (27)3.1 Description of ASEs (27)3.2 List of Application Specific Instructions (28)3.2.1 The MIPS16e Application Specific Extension to the MIPS32Architecture (28)3.2.2 The MDMX Application Specific Extension to the MIPS64 Architecture (28)3.2.3 The MIPS-3D Application Specific Extension to the MIPS64 Architecture (28)MIPS32™ Architecture For Programmers Volume I, Revision 2.00i Copyright © 2001-2003 MIPS Technologies Inc. All rights reserved.3.2.4 The SmartMIPS Application Specific Extension to the MIPS32 Architecture (28)Chapter 4 Overview of the CPU Instruction Set (29)4.1 CPU Instructions, Grouped By Function (29)4.1.1 CPU Load and Store Instructions (29)4.1.2 Computational Instructions (32)4.1.3 Jump and Branch Instructions (35)4.1.4 Miscellaneous Instructions (37)4.1.5 Coprocessor Instructions (40)4.2 CPU Instruction Formats (41)Chapter 5 Overview of the FPU Instruction Set (43)5.1 Binary Compatibility (43)5.2 Enabling the Floating Point Coprocessor (44)5.3 IEEE Standard 754 (44)5.4 FPU Data Types (44)5.4.1 Floating Point Formats (44)5.4.2 Fixed Point Formats (48)5.5 Floating Point Register Types (48)5.5.1 FPU Register Models (49)5.5.2 Binary Data Transfers (32-Bit and 64-Bit) (49)5.5.3 FPRs and Formatted Operand Layout (50)5.6 Floating Point Control Registers (FCRs) (50)5.6.1 Floating Point Implementation Register (FIR, CP1 Control Register 0) (51)5.6.2 Floating Point Control and Status Register (FCSR, CP1 Control Register 31) (53)5.6.3 Floating Point Condition Codes Register (FCCR, CP1 Control Register 25) (55)5.6.4 Floating Point Exceptions Register (FEXR, CP1 Control Register 26) (56)5.6.5 Floating Point Enables Register (FENR, CP1 Control Register 28) (56)5.7 Formats of Values Used in FP Registers (57)5.8 FPU Exceptions (58)5.8.1 Exception Conditions (59)5.9 FPU Instructions (62)5.9.1 Data Transfer Instructions (62)5.9.2 Arithmetic Instructions (63)5.9.3 Conversion Instructions (65)5.9.4 Formatted Operand-Value Move Instructions (66)5.9.5 Conditional Branch Instructions (67)5.9.6 Miscellaneous Instructions (68)5.10 Valid Operands for FPU Instructions (68)5.11 FPU Instruction Formats (70)5.11.1 Implementation Note (71)Appendix A Instruction Bit Encodings (75)A.1 Instruction Encodings and Instruction Classes (75)A.2 Instruction Bit Encoding Tables (75)A.3 Floating Point Unit Instruction Format Encodings (82)Appendix B Revision History (85)ii MIPS32™ Architecture For Programmers Volume I, Revision 2.00 Copyright © 2001-2003 MIPS Technologies Inc. All rights reserved.Figure 2-1: Relationship between the MIPS32 and MIPS64 Architectures (11)Figure 2-2: One-Deep Single-Completion Instruction Pipeline (13)Figure 2-3: Four-Deep Single-Completion Pipeline (14)Figure 2-4: Four-Deep Superpipeline (14)Figure 2-5: Four-Way Superscalar Pipeline (15)Figure 2-6: CPU Registers (18)Figure 2-7: FPU Registers for a 32-bit FPU (20)Figure 2-8: FPU Registers for a 64-bit FPU if Status FR is 1 (21)Figure 2-9: FPU Registers for a 64-bit FPU if Status FR is 0 (22)Figure 2-10: Big-Endian Byte Ordering (23)Figure 2-11: Little-Endian Byte Ordering (23)Figure 2-12: Big-Endian Data in Doubleword Format (24)Figure 2-13: Little-Endian Data in Doubleword Format (24)Figure 2-14: Big-Endian Misaligned Word Addressing (25)Figure 2-15: Little-Endian Misaligned Word Addressing (25)Figure 3-1: MIPS ISAs and ASEs (27)Figure 3-2: User-Mode MIPS ISAs and Optional ASEs (27)Figure 4-1: Immediate (I-Type) CPU Instruction Format (42)Figure 4-2: Jump (J-Type) CPU Instruction Format (42)Figure 4-3: Register (R-Type) CPU Instruction Format (42)Figure 5-1: Single-Precisions Floating Point Format (S) (45)Figure 5-2: Double-Precisions Floating Point Format (D) (45)Figure 5-3: Paired Single Floating Point Format (PS) (46)Figure 5-4: Word Fixed Point Format (W) (48)Figure 5-5: Longword Fixed Point Format (L) (48)Figure 5-6: FPU Word Load and Move-to Operations (49)Figure 5-7: FPU Doubleword Load and Move-to Operations (50)Figure 5-8: Single Floating Point or Word Fixed Point Operand in an FPR (50)Figure 5-9: Double Floating Point or Longword Fixed Point Operand in an FPR (50)Figure 5-10: Paired-Single Floating Point Operand in an FPR (50)Figure 5-11: FIR Register Format (51)Figure 5-12: FCSR Register Format (53)Figure 5-13: FCCR Register Format (55)Figure 5-14: FEXR Register Format (56)Figure 5-15: FENR Register Format (56)Figure 5-16: Effect of FPU Operations on the Format of Values Held in FPRs (58)Figure 5-17: I-Type (Immediate) FPU Instruction Format (71)Figure 5-18: R-Type (Register) FPU Instruction Format (71)Figure 5-19: Register-Immediate FPU Instruction Format (71)Figure 5-20: Condition Code, Immediate FPU Instruction Format (71)Figure 5-21: Formatted FPU Compare Instruction Format (71)Figure 5-22: FP RegisterMove, Conditional Instruction Format (71)Figure 5-23: Four-Register Formatted Arithmetic FPU Instruction Format (72)Figure 5-24: Register Index FPU Instruction Format (72)Figure 5-25: Register Index Hint FPU Instruction Format (72)Figure 5-26: Condition Code, Register Integer FPU Instruction Format (72)Figure A-1: Sample Bit Encoding Table (76)MIPS32™ Architecture For Programmers Volume I, Revision 2.00iii Copyright © 2001-2003 MIPS Technologies Inc. All rights reserved.Table 1-1: Symbols Used in Instruction Operation Statements (2)Table 2-1: MIPS32 Instructions (12)Table 2-2: MIPS64 Instructions (13)Table 2-3: Unaligned Load and Store Instructions (24)Table 4-1: Load and Store Operations Using Register + Offset Addressing Mode (30)Table 4-2: Aligned CPU Load/Store Instructions (30)Table 4-3: Unaligned CPU Load and Store Instructions (31)Table 4-4: Atomic Update CPU Load and Store Instructions (31)Table 4-5: Coprocessor Load and Store Instructions (31)Table 4-6: FPU Load and Store Instructions Using Register+Register Addressing (32)Table 4-7: ALU Instructions With an Immediate Operand (33)Table 4-8: Three-Operand ALU Instructions (33)Table 4-9: Two-Operand ALU Instructions (34)Table 4-10: Shift Instructions (34)Table 4-11: Multiply/Divide Instructions (35)Table 4-12: Unconditional Jump Within a 256 Megabyte Region (36)Table 4-13: PC-Relative Conditional Branch Instructions Comparing Two Registers (36)Table 4-14: PC-Relative Conditional Branch Instructions Comparing With Zero (37)Table 4-15: Deprecated Branch Likely Instructions (37)Table 4-16: Serialization Instruction (38)Table 4-17: System Call and Breakpoint Instructions (38)Table 4-18: Trap-on-Condition Instructions Comparing Two Registers (38)Table 4-19: Trap-on-Condition Instructions Comparing an Immediate Value (38)Table 4-20: CPU Conditional Move Instructions (39)Table 4-21: Prefetch Instructions (39)Table 4-22: NOP Instructions (40)Table 4-23: Coprocessor Definition and Use in the MIPS Architecture (40)Table 4-24: CPU Instruction Format Fields (42)Table 5-1: Parameters of Floating Point Data Types (45)Table 5-2: Value of Single or Double Floating Point DataType Encoding (46)Table 5-3: Value Supplied When a New Quiet NaN Is Created (47)Table 5-4: FIR Register Field Descriptions (51)Table 5-5: FCSR Register Field Descriptions (53)Table 5-6: Cause, Enable, and Flag Bit Definitions (55)Table 5-7: Rounding Mode Definitions (55)Table 5-8: FCCR Register Field Descriptions (56)Table 5-9: FEXR Register Field Descriptions (56)Table 5-10: FENR Register Field Descriptions (57)Table 5-11: Default Result for IEEE Exceptions Not Trapped Precisely (60)Table 5-12: FPU Data Transfer Instructions (62)Table 5-13: FPU Loads and Stores Using Register+Offset Address Mode (63)Table 5-14: FPU Loads and Using Register+Register Address Mode (63)Table 5-15: FPU Move To and From Instructions (63)Table 5-16: FPU IEEE Arithmetic Operations (64)Table 5-17: FPU-Approximate Arithmetic Operations (64)Table 5-18: FPU Multiply-Accumulate Arithmetic Operations (65)Table 5-19: FPU Conversion Operations Using the FCSR Rounding Mode (65)Table 5-20: FPU Conversion Operations Using a Directed Rounding Mode (65)Table 5-21: FPU Formatted Operand Move Instructions (66)Table 5-22: FPU Conditional Move on True/False Instructions (66)iv MIPS32™ Architecture For Programmers Volume I, Revision 2.00 Copyright © 2001-2003 MIPS Technologies Inc. All rights reserved.Table 5-23: FPU Conditional Move on Zero/Nonzero Instructions (67)Table 5-24: FPU Conditional Branch Instructions (67)Table 5-25: Deprecated FPU Conditional Branch Likely Instructions (67)Table 5-26: CPU Conditional Move on FPU True/False Instructions (68)Table 5-27: FPU Operand Format Field (fmt, fmt3) Encoding (68)Table 5-28: Valid Formats for FPU Operations (69)Table 5-29: FPU Instruction Format Fields (72)Table A-1: Symbols Used in the Instruction Encoding Tables (76)Table A-2: MIPS32 Encoding of the Opcode Field (77)Table A-3: MIPS32 SPECIAL Opcode Encoding of Function Field (78)Table A-4: MIPS32 REGIMM Encoding of rt Field (78)Table A-5: MIPS32 SPECIAL2 Encoding of Function Field (78)Table A-6: MIPS32 SPECIAL3 Encoding of Function Field for Release 2 of the Architecture (78)Table A-7: MIPS32 MOVCI Encoding of tf Bit (79)Table A-8: MIPS32 SRL Encoding of Shift/Rotate (79)Table A-9: MIPS32 SRLV Encoding of Shift/Rotate (79)Table A-10: MIPS32 BSHFL Encoding of sa Field (79)Table A-11: MIPS32 COP0 Encoding of rs Field (79)Table A-12: MIPS32 COP0 Encoding of Function Field When rs=CO (80)Table A-13: MIPS32 COP1 Encoding of rs Field (80)Table A-14: MIPS32 COP1 Encoding of Function Field When rs=S (80)Table A-15: MIPS32 COP1 Encoding of Function Field When rs=D (81)Table A-16: MIPS32 COP1 Encoding of Function Field When rs=W or L (81)Table A-17: MIPS64 COP1 Encoding of Function Field When rs=PS (81)Table A-18: MIPS32 COP1 Encoding of tf Bit When rs=S, D, or PS, Function=MOVCF (81)Table A-19: MIPS32 COP2 Encoding of rs Field (82)Table A-20: MIPS64 COP1X Encoding of Function Field (82)Table A-21: Floating Point Unit Instruction Format Encodings (82)MIPS32™ Architecture For Programmers Volume I, Revision 2.00v Copyright © 2001-2003 MIPS Technologies Inc. All rights reserved.vi MIPS32™ Architecture For Programmers Volume I, Revision 2.00 Copyright © 2001-2003 MIPS Technologies Inc. All rights reserved.Chapter 1About This BookThe MIPS32™ Architecture For Programmers V olume I comes as a multi-volume set.•V olume I describes conventions used throughout the document set, and provides an introduction to the MIPS32™Architecture•V olume II provides detailed descriptions of each instruction in the MIPS32™ instruction set•V olume III describes the MIPS32™Privileged Resource Architecture which deﬁnes and governs the behavior of the privileged resources included in a MIPS32™ processor implementation•V olume IV-a describes the MIPS16e™ Application-Speciﬁc Extension to the MIPS32™ Architecture•V olume IV-b describes the MDMX™ Application-Speciﬁc Extension to the MIPS32™ Architecture and is notapplicable to the MIPS32™ document set•V olume IV-c describes the MIPS-3D™ Application-Speciﬁc Extension to the MIPS64™ Architecture and is notapplicable to the MIPS32™ document set•V olume IV-d describes the SmartMIPS™Application-Speciﬁc Extension to the MIPS32™ Architecture1.1Typographical ConventionsThis section describes the use of italic,bold and courier fonts in this book.1.1.1Italic Text•is used for emphasis•is used for bits,ﬁelds,registers, that are important from a software perspective (for instance, address bits used bysoftware,and programmableﬁelds and registers),and variousﬂoating point instruction formats,such as S,D,and PS •is used for the memory access types, such as cached and uncached1.1.2Bold Text•represents a term that is being deﬁned•is used for bits andﬁelds that are important from a hardware perspective (for instance,register bits, which are not programmable but accessible only to hardware)•is used for ranges of numbers; the range is indicated by an ellipsis. For instance,5..1indicates numbers 5 through 1•is used to emphasize UNPREDICTABLE and UNDEFINED behavior, as deﬁned below.1.1.3Courier TextCourier ﬁxed-width font is used for text that is displayed on the screen, and for examples of code and instruction pseudocode.MIPS32™ Architecture For Programmers Volume I, Revision 2.001 Copyright © 2001-2003 MIPS Technologies Inc. All rights reserved.Chapter 1 About This Book1.2UNPREDICTABLE and UNDEFINEDThe terms UNPREDICTABLE and UNDEFINED are used throughout this book to describe the behavior of theprocessor in certain cases.UNDEFINED behavior or operations can occur only as the result of executing instructions in a privileged mode (i.e., in Kernel Mode or Debug Mode, or with the CP0 usable bit set in the Status register).Unprivileged software can never cause UNDEFINED behavior or operations. Conversely, both privileged andunprivileged software can cause UNPREDICTABLE results or operations.1.2.1UNPREDICTABLEUNPREDICTABLE results may vary from processor implementation to implementation,instruction to instruction,or as a function of time on the same implementation or instruction. Software can never depend on results that areUNPREDICTABLE.UNPREDICTABLE operations may cause a result to be generated or not.If a result is generated, it is UNPREDICTABLE.UNPREDICTABLE operations may cause arbitrary exceptions.UNPREDICTABLE results or operations have several implementation restrictions:•Implementations of operations generating UNPREDICTABLE results must not depend on any data source(memory or internal state) which is inaccessible in the current processor mode•UNPREDICTABLE operations must not read, write, or modify the contents of memory or internal state which is inaccessible in the current processor mode. For example,UNPREDICTABLE operations executed in user modemust not access memory or internal state that is only accessible in Kernel Mode or Debug Mode or in another process •UNPREDICTABLE operations must not halt or hang the processor1.2.2UNDEFINEDUNDEFINED operations or behavior may vary from processor implementation to implementation, instruction toinstruction, or as a function of time on the same implementation or instruction.UNDEFINED operations or behavior may vary from nothing to creating an environment in which execution can no longer continue.UNDEFINED operations or behavior may cause data loss.UNDEFINED operations or behavior has one implementation restriction:•UNDEFINED operations or behavior must not cause the processor to hang(that is,enter a state from which there is no exit other than powering down the processor).The assertion of any of the reset signals must restore the processor to an operational state1.3Special Symbols in Pseudocode NotationIn this book, algorithmic descriptions of an operation are described as pseudocode in a high-level language notation resembling Pascal. Special symbols used in the pseudocode notation are listed in Table 1-1.Table 1-1 Symbols Used in Instruction Operation StatementsSymbol Meaning←Assignment=, ≠Tests for equality and inequality||Bit string concatenationx y A y-bit string formed by y copies of the single-bit value x2MIPS32™ Architecture For Programmers Volume I, Revision 2.00 Copyright © 2001-2003 MIPS Technologies Inc. All rights reserved.1.3Special Symbols in Pseudocode Notationb#n A constant value n in base b.For instance10#100represents the decimal value100,2#100represents the binary value 100 (decimal 4), and 16#100 represents the hexadecimal value 100 (decimal 256). If the "b#" preﬁx is omitted, the default base is 10.x y..z Selection of bits y through z of bit string x.Little-endian bit notation(rightmost bit is0)is used.If y is less than z, this expression is an empty (zero length) bit string.+, −2’s complement or ﬂoating point arithmetic: addition, subtraction∗, ×2’s complement or ﬂoating point multiplication (both used for either)div2’s complement integer divisionmod2’s complement modulo/Floating point division<2’s complement less-than comparison>2’s complement greater-than comparison≤2’s complement less-than or equal comparison≥2’s complement greater-than or equal comparisonnor Bitwise logical NORxor Bitwise logical XORand Bitwise logical ANDor Bitwise logical ORGPRLEN The length in bits (32 or 64) of the CPU general-purpose registersGPR[x]CPU general-purpose register x. The content of GPR[0] is always zero.SGPR[s,x]In Release 2 of the Architecture, multiple copies of the CPU general-purpose registers may be implemented.SGPR[s,x] refers to GPR set s, register x. GPR[x] is a short-hand notation for SGPR[ SRSCtl CSS, x].FPR[x]Floating Point operand register xFCC[CC]Floating Point condition code CC.FCC[0] has the same value as COC[1].FPR[x]Floating Point (Coprocessor unit 1), general register xCPR[z,x,s]Coprocessor unit z, general register x,select sCP2CPR[x]Coprocessor unit 2, general register xCCR[z,x]Coprocessor unit z, control register xCP2CCR[x]Coprocessor unit 2, control register xCOC[z]Coprocessor unit z condition signalXlat[x]Translation of the MIPS16e GPR number x into the corresponding 32-bit GPR numberBigEndianMem Endian mode as conﬁgured at chip reset (0→Little-Endian, 1→ Big-Endian). Speciﬁes the endianness of the memory interface(see LoadMemory and StoreMemory pseudocode function descriptions),and the endianness of Kernel and Supervisor mode execution.BigEndianCPU The endianness for load and store instructions (0→ Little-Endian, 1→ Big-Endian). In User mode, this endianness may be switched by setting the RE bit in the Status register.Thus,BigEndianCPU may be computed as (BigEndianMem XOR ReverseEndian).Table 1-1 Symbols Used in Instruction Operation StatementsSymbol MeaningChapter 1 About This Book1.4For More InformationVarious MIPS RISC processor manuals and additional information about MIPS products can be found at the MIPS URL:ReverseEndianSignal to reverse the endianness of load and store instructions.This feature is available in User mode only,and is implemented by setting the RE bit of the Status register.Thus,ReverseEndian may be computed as (SR RE and User mode).LLbitBit of virtual state used to specify operation for instructions that provide atomic read-modify-write.LLbit is set when a linked load occurs; it is tested and cleared by the conditional store. It is cleared, during other CPU operation,when a store to the location would no longer be atomic.In particular,it is cleared by exception return instructions.I :,I+n :,I-n :This occurs as a preﬁx to Operation description lines and functions as a label. It indicates the instruction time during which the pseudocode appears to “execute.” Unless otherwise indicated, all effects of the currentinstruction appear to occur during the instruction time of the current instruction.No label is equivalent to a time label of I . Sometimes effects of an instruction appear to occur either earlier or later — that is, during theinstruction time of another instruction.When this happens,the instruction operation is written in sections labeled with the instruction time,relative to the current instruction I ,in which the effect of that pseudocode appears to occur.For example,an instruction may have a result that is not available until after the next instruction.Such an instruction has the portion of the instruction operation description that writes the result register in a section labeled I +1.The effect of pseudocode statements for the current instruction labelled I +1appears to occur “at the same time”as the effect of pseudocode statements labeled I for the following instruction.Within one pseudocode sequence,the effects of the statements take place in order. However, between sequences of statements for differentinstructions that occur “at the same time,” there is no deﬁned order. Programs must not depend on a particular order of evaluation between such sections.PCThe Program Counter value.During the instruction time of an instruction,this is the address of the instruction word. The address of the instruction that occurs during the next instruction time is determined by assigning a value to PC during an instruction time. If no value is assigned to PC during an instruction time by anypseudocode statement,it is automatically incremented by either 2(in the case of a 16-bit MIPS16e instruction)or 4before the next instruction time.A taken branch assigns the target address to the PC during the instruction time of the instruction in the branch delay slot.PABITSThe number of physical address bits implemented is represented by the symbol PABITS.As such,if 36physical address bits were implemented, the size of the physical address space would be 2PABITS = 236 bytes.FP32RegistersModeIndicates whether the FPU has 32-bit or 64-bit ﬂoating point registers (FPRs).In MIPS32,the FPU has 3232-bit FPRs in which 64-bit data types are stored in even-odd pairs of FPRs.In MIPS64,the FPU has 3264-bit FPRs in which 64-bit data types are stored in any FPR.In MIPS32implementations,FP32RegistersMode is always a 0.MIPS64implementations have a compatibility mode in which the processor references the FPRs as if it were a MIPS32 implementation. In such a caseFP32RegisterMode is computed from the FR bit in the Status register.If this bit is a 0,the processor operates as if it had 32 32-bit FPRs. If this bit is a 1, the processor operates with 32 64-bit FPRs.The value of FP32RegistersMode is computed from the FR bit in the Status register.InstructionInBranchDelaySlotIndicates whether the instruction at the Program Counter address was executed in the delay slot of a branch or jump. This condition reﬂects the dynamic state of the instruction, not the static state. That is, the value is false if a branch or jump occurs to an instruction whose PC immediately follows a branch or jump, but which is not executed in the delay slot of a branch or jump.SignalException(exce ption, argument)Causes an exception to be signaled, using the exception parameter as the type of exception and the argument parameter as an exception-speciﬁc argument). Control does not return from this pseudocode function - the exception is signaled at the point of the call.Table 1-1 Symbols Used in Instruction Operation StatementsSymbolMeaning。

物理学专业英语

华中师范大学物理学院物理学专业英语仅供内部学习参考！2014一、课程的任务和教学目的通过学习《物理学专业英语》，学生将掌握物理学领域使用频率较高的专业词汇和表达方法，进而具备基本的阅读理解物理学专业文献的能力。

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3.掌握基本专业词汇（不少于200词）。

4.应具有流利阅读、翻译及赏析专业英语文献，并能简单地进行写作的能力。

四、参考书目录1 Physics 物理学 (1)Introduction to physics (1)Classical and modern physics (2)Research fields (4)V ocabulary (7)2 Classical mechanics 经典力学 (10)Introduction (10)Description of classical mechanics (10)Momentum and collisions (14)Angular momentum (15)V ocabulary (16)3 Thermodynamics 热力学 (18)Introduction (18)Laws of thermodynamics (21)System models (22)Thermodynamic processes (27)Scope of thermodynamics (29)V ocabulary (30)4 Electromagnetism 电磁学 (33)Introduction (33)Electrostatics (33)Magnetostatics (35)Electromagnetic induction (40)V ocabulary (43)5 Optics 光学 (45)Introduction (45)Geometrical optics (45)Physical optics (47)Polarization (50)V ocabulary (51)6 Atomic physics 原子物理 (52)Introduction (52)Electronic configuration (52)Excitation and ionization (56)V ocabulary (59)7 Statistical mechanics 统计力学 (60)Overview (60)Fundamentals (60)Statistical ensembles (63)V ocabulary (65)8 Quantum mechanics 量子力学 (67)Introduction (67)Mathematical formulations (68)Quantization (71)Wave-particle duality (72)Quantum entanglement (75)V ocabulary (77)9 Special relativity 狭义相对论 (79)Introduction (79)Relativity of simultaneity (80)Lorentz transformations (80)Time dilation and length contraction (81)Mass-energy equivalence (82)Relativistic energy-momentum relation (86)V ocabulary (89)正文标记说明：蓝色Arial字体（例如energy）：已知的专业词汇蓝色Arial字体加下划线（例如electromagnetism）：新学的专业词汇黑色Times New Roman字体加下划线（例如postulate）：新学的普通词汇1 Physics 物理学1 Physics 物理学Introduction to physicsPhysics is a part of natural philosophy and a natural science that involves the study of matter and its motion through space and time, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic disciplines, perhaps the oldest through its inclusion of astronomy. Over the last two millennia, physics was a part of natural philosophy along with chemistry, certain branches of mathematics, and biology, but during the Scientific Revolution in the 17th century, the natural sciences emerged as unique research programs in their own right. Physics intersects with many interdisciplinary areas of research, such as biophysics and quantum chemistry,and the boundaries of physics are not rigidly defined. New ideas in physics often explain the fundamental mechanisms of other sciences, while opening new avenues of research in areas such as mathematics and philosophy.Physics also makes significant contributions through advances in new technologies that arise from theoretical breakthroughs. For example, advances in the understanding of electromagnetism or nuclear physics led directly to the development of new products which have dramatically transformed modern-day society, such as television, computers, domestic appliances, and nuclear weapons; advances in thermodynamics led to the development of industrialization; and advances in mechanics inspired the development of calculus.Core theoriesThough physics deals with a wide variety of systems, certain theories are used by all physicists. Each of these theories were experimentally tested numerous times and found correct as an approximation of nature (within a certain domain of validity).For instance, the theory of classical mechanics accurately describes the motion of objects, provided they are much larger than atoms and moving at much less than the speed of light. These theories continue to be areas of active research, and a remarkable aspect of classical mechanics known as chaos was discovered in the 20th century, three centuries after the original formulation of classical mechanics by Isaac Newton (1642–1727) 【艾萨克·牛顿】.University PhysicsThese central theories are important tools for research into more specialized topics, and any physicist, regardless of his or her specialization, is expected to be literate in them. These include classical mechanics, quantum mechanics, thermodynamics and statistical mechanics, electromagnetism, and special relativity.Classical and modern physicsClassical mechanicsClassical physics includes the traditional branches and topics that were recognized and well-developed before the beginning of the 20th century—classical mechanics, acoustics, optics, thermodynamics, and electromagnetism.Classical mechanics is concerned with bodies acted on by forces and bodies in motion and may be divided into statics (study of the forces on a body or bodies at rest), kinematics (study of motion without regard to its causes), and dynamics (study of motion and the forces that affect it); mechanics may also be divided into solid mechanics and fluid mechanics (known together as continuum mechanics), the latter including such branches as hydrostatics, hydrodynamics, aerodynamics, and pneumatics.Acoustics is the study of how sound is produced, controlled, transmitted and received. Important modern branches of acoustics include ultrasonics, the study of sound waves of very high frequency beyond the range of human hearing; bioacoustics the physics of animal calls and hearing, and electroacoustics, the manipulation of audible sound waves using electronics.Optics, the study of light, is concerned not only with visible light but also with infrared and ultraviolet radiation, which exhibit all of the phenomena of visible light except visibility, e.g., reflection, refraction, interference, diffraction, dispersion, and polarization of light.Heat is a form of energy, the internal energy possessed by the particles of which a substance is composed; thermodynamics deals with the relationships between heat and other forms of energy.Electricity and magnetism have been studied as a single branch of physics since the intimate connection between them was discovered in the early 19th century; an electric current gives rise to a magnetic field and a changing magnetic field induces an electric current. Electrostatics deals with electric charges at rest, electrodynamics with moving charges, and magnetostatics with magnetic poles at rest.Modern PhysicsClassical physics is generally concerned with matter and energy on the normal scale of1 Physics 物理学observation, while much of modern physics is concerned with the behavior of matter and energy under extreme conditions or on the very large or very small scale.For example, atomic and nuclear physics studies matter on the smallest scale at which chemical elements can be identified.The physics of elementary particles is on an even smaller scale, as it is concerned with the most basic units of matter; this branch of physics is also known as high-energy physics because of the extremely high energies necessary to produce many types of particles in large particle accelerators. On this scale, ordinary, commonsense notions of space, time, matter, and energy are no longer valid.The two chief theories of modern physics present a different picture of the concepts of space, time, and matter from that presented by classical physics.Quantum theory is concerned with the discrete, rather than continuous, nature of many phenomena at the atomic and subatomic level, and with the complementary aspects of particles and waves in the description of such phenomena.The theory of relativity is concerned with the description of phenomena that take place in a frame of reference that is in motion with respect to an observer; the special theory of relativity is concerned with relative uniform motion in a straight line and the general theory of relativity with accelerated motion and its connection with gravitation.Both quantum theory and the theory of relativity find applications in all areas of modern physics.Difference between classical and modern physicsWhile physics aims to discover universal laws, its theories lie in explicit domains of applicability. Loosely speaking, the laws of classical physics accurately describe systems whose important length scales are greater than the atomic scale and whose motions are much slower than the speed of light. Outside of this domain, observations do not match their predictions.Albert Einstein【阿尔伯特·爱因斯坦】contributed the framework of special relativity, which replaced notions of absolute time and space with space-time and allowed an accurate description of systems whose components have speeds approaching the speed of light.Max Planck【普朗克】, Erwin Schrödinger【薛定谔】, and others introduced quantum mechanics, a probabilistic notion of particles and interactions that allowed an accurate description of atomic and subatomic scales.Later, quantum field theory unified quantum mechanics and special relativity.General relativity allowed for a dynamical, curved space-time, with which highly massiveUniversity Physicssystems and the large-scale structure of the universe can be well-described. General relativity has not yet been unified with the other fundamental descriptions; several candidate theories of quantum gravity are being developed.Research fieldsContemporary research in physics can be broadly divided into condensed matter physics; atomic, molecular, and optical physics; particle physics; astrophysics; geophysics and biophysics. Some physics departments also support research in Physics education.Since the 20th century, the individual fields of physics have become increasingly specialized, and today most physicists work in a single field for their entire careers. "Universalists" such as Albert Einstein (1879–1955) and Lev Landau (1908–1968)【列夫·朗道】, who worked in multiple fields of physics, are now very rare.Condensed matter physicsCondensed matter physics is the field of physics that deals with the macroscopic physical properties of matter. In particular, it is concerned with the "condensed" phases that appear whenever the number of particles in a system is extremely large and the interactions between them are strong.The most familiar examples of condensed phases are solids and liquids, which arise from the bonding by way of the electromagnetic force between atoms. More exotic condensed phases include the super-fluid and the Bose–Einstein condensate found in certain atomic systems at very low temperature, the superconducting phase exhibited by conduction electrons in certain materials,and the ferromagnetic and antiferromagnetic phases of spins on atomic lattices.Condensed matter physics is by far the largest field of contemporary physics.Historically, condensed matter physics grew out of solid-state physics, which is now considered one of its main subfields. The term condensed matter physics was apparently coined by Philip Anderson when he renamed his research group—previously solid-state theory—in 1967. In 1978, the Division of Solid State Physics of the American Physical Society was renamed as the Division of Condensed Matter Physics.Condensed matter physics has a large overlap with chemistry, materials science, nanotechnology and engineering.Atomic, molecular and optical physicsAtomic, molecular, and optical physics (AMO) is the study of matter–matter and light–matter interactions on the scale of single atoms and molecules.1 Physics 物理学The three areas are grouped together because of their interrelationships, the similarity of methods used, and the commonality of the energy scales that are relevant. All three areas include both classical, semi-classical and quantum treatments; they can treat their subject from a microscopic view (in contrast to a macroscopic view).Atomic physics studies the electron shells of atoms. Current research focuses on activities in quantum control, cooling and trapping of atoms and ions, low-temperature collision dynamics and the effects of electron correlation on structure and dynamics. Atomic physics is influenced by the nucleus (see, e.g., hyperfine splitting), but intra-nuclear phenomena such as fission and fusion are considered part of high-energy physics.Molecular physics focuses on multi-atomic structures and their internal and external interactions with matter and light.Optical physics is distinct from optics in that it tends to focus not on the control of classical light fields by macroscopic objects, but on the fundamental properties of optical fields and their interactions with matter in the microscopic realm.High-energy physics (particle physics) and nuclear physicsParticle physics is the study of the elementary constituents of matter and energy, and the interactions between them.In addition, particle physicists design and develop the high energy accelerators,detectors, and computer programs necessary for this research. The field is also called "high-energy physics" because many elementary particles do not occur naturally, but are created only during high-energy collisions of other particles.Currently, the interactions of elementary particles and fields are described by the Standard Model.●The model accounts for the 12 known particles of matter (quarks and leptons) thatinteract via the strong, weak, and electromagnetic fundamental forces.●Dynamics are described in terms of matter particles exchanging gauge bosons (gluons,W and Z bosons, and photons, respectively).●The Standard Model also predicts a particle known as the Higgs boson. In July 2012CERN, the European laboratory for particle physics, announced the detection of a particle consistent with the Higgs boson.Nuclear Physics is the field of physics that studies the constituents and interactions of atomic nuclei. The most commonly known applications of nuclear physics are nuclear power generation and nuclear weapons technology, but the research has provided application in many fields, including those in nuclear medicine and magnetic resonance imaging, ion implantation in materials engineering, and radiocarbon dating in geology and archaeology.University PhysicsAstrophysics and Physical CosmologyAstrophysics and astronomy are the application of the theories and methods of physics to the study of stellar structure, stellar evolution, the origin of the solar system, and related problems of cosmology. Because astrophysics is a broad subject, astrophysicists typically apply many disciplines of physics, including mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic and molecular physics.The discovery by Karl Jansky in 1931 that radio signals were emitted by celestial bodies initiated the science of radio astronomy. Most recently, the frontiers of astronomy have been expanded by space exploration. Perturbations and interference from the earth's atmosphere make space-based observations necessary for infrared, ultraviolet, gamma-ray, and X-ray astronomy.Physical cosmology is the study of the formation and evolution of the universe on its largest scales. Albert Einstein's theory of relativity plays a central role in all modern cosmological theories. In the early 20th century, Hubble's discovery that the universe was expanding, as shown by the Hubble diagram, prompted rival explanations known as the steady state universe and the Big Bang.The Big Bang was confirmed by the success of Big Bang nucleo-synthesis and the discovery of the cosmic microwave background in 1964. The Big Bang model rests on two theoretical pillars: Albert Einstein's general relativity and the cosmological principle (On a sufficiently large scale, the properties of the Universe are the same for all observers). Cosmologists have recently established the ΛCDM model (the standard model of Big Bang cosmology) of the evolution of the universe, which includes cosmic inflation, dark energy and dark matter.Current research frontiersIn condensed matter physics, an important unsolved theoretical problem is that of high-temperature superconductivity. Many condensed matter experiments are aiming to fabricate workable spintronics and quantum computers.In particle physics, the first pieces of experimental evidence for physics beyond the Standard Model have begun to appear. Foremost among these are indications that neutrinos have non-zero mass. These experimental results appear to have solved the long-standing solar neutrino problem, and the physics of massive neutrinos remains an area of active theoretical and experimental research. Particle accelerators have begun probing energy scales in the TeV range, in which experimentalists are hoping to find evidence for the super-symmetric particles, after discovery of the Higgs boson.Theoretical attempts to unify quantum mechanics and general relativity into a single theory1 Physics 物理学of quantum gravity, a program ongoing for over half a century, have not yet been decisively resolved. The current leading candidates are M-theory, superstring theory and loop quantum gravity.Many astronomical and cosmological phenomena have yet to be satisfactorily explained, including the existence of ultra-high energy cosmic rays, the baryon asymmetry, the acceleration of the universe and the anomalous rotation rates of galaxies.Although much progress has been made in high-energy, quantum, and astronomical physics, many everyday phenomena involving complexity, chaos, or turbulence are still poorly understood. Complex problems that seem like they could be solved by a clever application of dynamics and mechanics remain unsolved; examples include the formation of sand-piles, nodes in trickling water, the shape of water droplets, mechanisms of surface tension catastrophes, and self-sorting in shaken heterogeneous collections.These complex phenomena have received growing attention since the 1970s for several reasons, including the availability of modern mathematical methods and computers, which enabled complex systems to be modeled in new ways. Complex physics has become part of increasingly interdisciplinary research, as exemplified by the study of turbulence in aerodynamics and the observation of pattern formation in biological systems.Vocabulary★natural science 自然科学academic disciplines 学科astronomy 天文学in their own right 凭他们本身的实力intersects相交，交叉interdisciplinary交叉学科的，跨学科的★quantum 量子的theoretical breakthroughs 理论突破★electromagnetism 电磁学dramatically显著地★thermodynamics热力学★calculus微积分validity★classical mechanics 经典力学chaos 混沌literate 学者★quantum mechanics量子力学★thermodynamics and statistical mechanics热力学与统计物理★special relativity狭义相对论is concerned with 关注，讨论，考虑acoustics 声学★optics 光学statics静力学at rest 静息kinematics运动学★dynamics动力学ultrasonics超声学manipulation 操作，处理，使用University Physicsinfrared红外ultraviolet紫外radiation辐射reflection 反射refraction 折射★interference 干涉★diffraction 衍射dispersion散射★polarization 极化，偏振internal energy 内能Electricity电性Magnetism 磁性intimate 亲密的induces 诱导，感应scale尺度★elementary particles基本粒子★high-energy physics 高能物理particle accelerators 粒子加速器valid 有效的，正当的★discrete离散的continuous 连续的complementary 互补的★frame of reference 参照系★the special theory of relativity 狭义相对论★general theory of relativity 广义相对论gravitation 重力，万有引力explicit 详细的，清楚的★quantum field theory 量子场论★condensed matter physics凝聚态物理astrophysics天体物理geophysics地球物理Universalist博学多才者★Macroscopic宏观Exotic奇异的★Superconducting 超导Ferromagnetic铁磁质Antiferromagnetic 反铁磁质★Spin自旋Lattice 晶格，点阵，网格★Society社会，学会★microscopic微观的hyperfine splitting超精细分裂fission分裂，裂变fusion熔合，聚变constituents成分，组分accelerators加速器detectors 检测器★quarks夸克lepton 轻子gauge bosons规范玻色子gluons胶子★Higgs boson希格斯玻色子CERN欧洲核子研究中心★Magnetic Resonance Imaging磁共振成像，核磁共振ion implantation 离子注入radiocarbon dating放射性碳年代测定法geology地质学archaeology考古学stellar 恒星cosmology宇宙论celestial bodies 天体Hubble diagram 哈勃图Rival竞争的★Big Bang大爆炸nucleo-synthesis核聚合，核合成pillar支柱cosmological principle宇宙学原理ΛCDM modelΛ-冷暗物质模型cosmic inflation宇宙膨胀1 Physics 物理学fabricate制造，建造spintronics自旋电子元件，自旋电子学★neutrinos 中微子superstring 超弦baryon重子turbulence湍流，扰动，骚动catastrophes突变，灾变，灾难heterogeneous collections异质性集合pattern formation模式形成University Physics2 Classical mechanics 经典力学IntroductionIn physics, classical mechanics is one of the two major sub-fields of mechanics, which is concerned with the set of physical laws describing the motion of bodies under the action of a system of forces. The study of the motion of bodies is an ancient one, making classical mechanics one of the oldest and largest subjects in science, engineering and technology.Classical mechanics describes the motion of macroscopic objects, from projectiles to parts of machinery, as well as astronomical objects, such as spacecraft, planets, stars, and galaxies. Besides this, many specializations within the subject deal with gases, liquids, solids, and other specific sub-topics.Classical mechanics provides extremely accurate results as long as the domain of study is restricted to large objects and the speeds involved do not approach the speed of light. When the objects being dealt with become sufficiently small, it becomes necessary to introduce the other major sub-field of mechanics, quantum mechanics, which reconciles the macroscopic laws of physics with the atomic nature of matter and handles the wave–particle duality of atoms and molecules. In the case of high velocity objects approaching the speed of light, classical mechanics is enhanced by special relativity. General relativity unifies special relativity with Newton's law of universal gravitation, allowing physicists to handle gravitation at a deeper level.The initial stage in the development of classical mechanics is often referred to as Newtonian mechanics, and is associated with the physical concepts employed by and the mathematical methods invented by Newton himself, in parallel with Leibniz【莱布尼兹】, and others.Later, more abstract and general methods were developed, leading to reformulations of classical mechanics known as Lagrangian mechanics and Hamiltonian mechanics. These advances were largely made in the 18th and 19th centuries, and they extend substantially beyond Newton's work, particularly through their use of analytical mechanics. Ultimately, the mathematics developed for these were central to the creation of quantum mechanics.Description of classical mechanicsThe following introduces the basic concepts of classical mechanics. For simplicity, it often2 Classical mechanics 经典力学models real-world objects as point particles, objects with negligible size. The motion of a point particle is characterized by a small number of parameters: its position, mass, and the forces applied to it.In reality, the kind of objects that classical mechanics can describe always have a non-zero size. (The physics of very small particles, such as the electron, is more accurately described by quantum mechanics). Objects with non-zero size have more complicated behavior than hypothetical point particles, because of the additional degrees of freedom—for example, a baseball can spin while it is moving. However, the results for point particles can be used to study such objects by treating them as composite objects, made up of a large number of interacting point particles. The center of mass of a composite object behaves like a point particle.Classical mechanics uses common-sense notions of how matter and forces exist and interact. It assumes that matter and energy have definite, knowable attributes such as where an object is in space and its speed. It also assumes that objects may be directly influenced only by their immediate surroundings, known as the principle of locality.In quantum mechanics objects may have unknowable position or velocity, or instantaneously interact with other objects at a distance.Position and its derivativesThe position of a point particle is defined with respect to an arbitrary fixed reference point, O, in space, usually accompanied by a coordinate system, with the reference point located at the origin of the coordinate system. It is defined as the vector r from O to the particle.In general, the point particle need not be stationary relative to O, so r is a function of t, the time elapsed since an arbitrary initial time.In pre-Einstein relativity (known as Galilean relativity), time is considered an absolute, i.e., the time interval between any given pair of events is the same for all observers. In addition to relying on absolute time, classical mechanics assumes Euclidean geometry for the structure of space.Velocity and speedThe velocity, or the rate of change of position with time, is defined as the derivative of the position with respect to time. In classical mechanics, velocities are directly additive and subtractive as vector quantities; they must be dealt with using vector analysis.When both objects are moving in the same direction, the difference can be given in terms of speed only by ignoring direction.University PhysicsAccelerationThe acceleration , or rate of change of velocity, is the derivative of the velocity with respect to time (the second derivative of the position with respect to time).Acceleration can arise from a change with time of the magnitude of the velocity or of the direction of the velocity or both . If only the magnitude v of the velocity decreases, this is sometimes referred to as deceleration , but generally any change in the velocity with time, including deceleration, is simply referred to as acceleration.Inertial frames of referenceWhile the position and velocity and acceleration of a particle can be referred to any observer in any state of motion, classical mechanics assumes the existence of a special family of reference frames in terms of which the mechanical laws of nature take a comparatively simple form. These special reference frames are called inertial frames .An inertial frame is such that when an object without any force interactions (an idealized situation) is viewed from it, it appears either to be at rest or in a state of uniform motion in a straight line. This is the fundamental definition of an inertial frame. They are characterized by the requirement that all forces entering the observer's physical laws originate in identifiable sources (charges, gravitational bodies, and so forth).A non-inertial reference frame is one accelerating with respect to an inertial one, and in such a non-inertial frame a particle is subject to acceleration by fictitious forces that enter the equations of motion solely as a result of its accelerated motion, and do not originate in identifiable sources. These fictitious forces are in addition to the real forces recognized in an inertial frame.A key concept of inertial frames is the method for identifying them. For practical purposes, reference frames that are un-accelerated with respect to the distant stars are regarded as good approximations to inertial frames.Forces; Newton's second lawNewton was the first to mathematically express the relationship between force and momentum . Some physicists interpret Newton's second law of motion as a definition of force and mass, while others consider it a fundamental postulate, a law of nature. Either interpretation has the same mathematical consequences, historically known as "Newton's Second Law":a m t v m t p F ===d )(d d dThe quantity m v is called the (canonical ) momentum . The net force on a particle is thus equal to rate of change of momentum of the particle with time.So long as the force acting on a particle is known, Newton's second law is sufficient to。

地磁场漂移与倒转

GGALVANIC DISTORTIONThe electrical conductivity of Earth materials affects two physical processes:electromagnetic induction which is utilized with magneto-tellurics(MT)(q.v.),and electrical conduction.If electromagnetic induction in media which are heterogeneous with respect to their elec-trical conductivity is considered,then both processes take place simul-taneously:Due to Faraday’s law,a variational electric field is induced in the Earth,and due to the conductivity of the subsoil an electric cur-rent flows as a consequence of the electric field.The current compo-nent normal to boundaries within the heterogeneous structure passes these boundaries continously according tos1E1¼s2E2where the subscripts1and2indicate the boundary values of conductiv-ity and electric field in regions1and2,respectively.Therefore the amplitude and the direction of the electric field are changed in the vicinity of the boundaries(Figure G1).In electromagnetic induction studies,the totality of these changes in comparison with the electric field distribution in homogeneous media is referred to as galvanic distortion. The electrical conductivity of Earth materials spans13orders of mag-nitude(e.g.,dry crystalline rocks can have conductivities of less than 10–6S mÀ1,while ores can have conductivities exceeding106S mÀ1). Therefore,MT has a potential for producing well constrained mod-els of the Earth’s electrical conductivity structure,but almost all field studies are affected by the phenomenon of galvanic distortion, and sophisticated techniques have been developed for dealing with it(Simpson and Bahr,2005).Electric field amplitude changes and static shiftA change in an electric field amplitude causes a frequency-indepen-dent offset in apparent resistivity curves so that they plot parallel to their true level,but are scaled by a real factor.Because this shift can be regarded as spatial undersampling or“aliasing,”the scaling factor or static shift factor cannot be determined directly from MT data recorded at a single site.If MT data are interpreted via one-dimensional modeling without correcting for static shift,the depth to a conductive body will be shifted by the square root of the factor by which the apparent resistivities are shifted.Static shift corrections may be classified into three broad groups: 1.Short period corrections relying on active near-surface measurementssuch as transient electromagnetic sounding(TEM)(e.g.,Meju,1996).2.Averaging(statistical)techniques.As an example,electromagneticarray profiling is an adaptation of the magnetotelluric technique that involves sampling lateral variations in the electric field con-tinuously,and spatial low pass filtering can be used to suppress sta-tic shift effects(Torres-Verdin and Bostick,1992).3.Long period corrections relying on assumed deep structure(e.g.,a resistivity drop at the mid-mantle transition zones)or long-periodmagnetic transfer functions(Schmucker,1973).An equivalence relationship exists between the magnetotelluric impedance Z and Schmucker’s C-response:C¼Zi om0;which can be determined from the magnetic fields alone,thereby providing an inductive scale length that is independent of the dis-torted electric field.Magnetic transfer functions can,for example, be derived from the magnetic daily variation.The appropriate method for correcting static shift often depends on the target depth,because there can be a continuum of distortion at all scales.As an example,in complex three-dimensional environments near-surface correction techniques may be inadequate if the conductiv-ity of the mantle is considered,because electrical heterogeneity in the deep crust creates additional galvanic distortion at a larger-scale, which is not resolved with near-surface measurements(e.g.,Simpson and Bahr,2005).Changes in the direction of electric fields and mixing of polarizationsIn some target areas of the MT method the conductivity distribution is two-dimensional(e.g.,in the case of electrical anisotropy(q.v.))and the induction process can be described by two decoupled polarizations of the electromagnetic field(e.g.,Simpson and Bahr,2005).Then,the changes in the direction of electric fields that are associated with galvanic distortion can result in mixing of these two polarizations. The recovery of the undistorted electromagnetic field is referred to as magnetotelluric tensor decomposition(e.g.,Bahr,1988,Groom and Bailey,1989).Current channeling and the“magnetic”distortionIn the case of extreme conductivity contrasts the electrical current can be channeled in such way that it is surrounded by a magneticvariational field that has,opposite to the assumptions made in the geo-magnetic deep sounding(q.v.)method,no phase lag with respect to the electric field.The occurrence of such magnetic fields in field data has been shown by Zhang et al.(1993)and Ritter and Banks(1998).An example of a magnetotelluric tensor decomposition that includes mag-netic distortion has been presented by Chave and Smith(1994).Karsten BahrBibliographyBahr,K.,1988.Interpretation of the magnetotelluric impedance tensor: regional induction and local telluric distortion.Journal of Geophy-sics,62:119–127.Chave,A.D.,and Smith,J.T.,1994.On electric and magnetic galvanic distortion tensor decompositions.Journal of Geophysical Research,99:4669–4682.Groom,R.W.,and Bailey,R.C.,1989.Decomposition of the magneto-telluric impedance tensor in the presence of local three-dimensional galvanic distortion.Journal of Geophysical Research,94: 1913–1925.Meju,M.A.,1996.Joint inversion of TEM and distorted MT sound-ings:some effective practical considerations.Geophysics,61: 56–65.Ritter,P.,and Banks,R.J.,1998.Separation of local and regional information in distorted GDS response functions by hypothetical event analysis.Geophysical Journal International,135:923–942. Schmucker,U.,1973.Regional induction studies:a review of methods and results.Physics of the Earth and Planetary Interiors,7: 365–378.Simpson,F.,and Bahr,K.,2005.Practical Magnetotellurics.Cam-bridge:Cambridge University Press.Torres-Verdin,C.,and Bostick,F.X.,1992.Principles of special sur-face electric field filtering in magnetotellurics:electromagnetic array profiling(EMAP).Geophysics,57:603–622.Zhang,P.,Pedersen,L.B.,Mareschal,M.,and Chouteau,M.,1993.Channelling contribution to tipper vectors:a magnetic equivalent to electrical distortion.Geophysical Journal International,113: 693–700.Cross-referencesAnisotropy,ElectricalGeomagnetic Deep SoundingMagnetotelluricsMantle,Electrical Conductivity,Mineralogy GAUSS’DETERMINATION OF ABSOLUTE INTENSITYThe concept of magnetic intensity was known as early as1600in De Magnete(see Gilbert,William).The relative intensity of the geomag-netic field in different locations could be measured with some preci-sion from the rate of oscillation of a dip needle—a method used by Humboldt,Alexander von(q.v.)in South America in1798.But it was not until Gauss became interested in a universal system of units that the idea of measuring absolute intensity,in terms of units of mass, length,and time,was considered.It is now difficult to imagine how revolutionary was the idea that something as subtle as magnetism could be measured in such mundane units.On18February1832,Gauss,Carl Friedrich(q.v.)wrote to the German astronomer Olbers:“I occupy myself now with the Earth’s magnetism,particularly with an absolute determination of its intensity.Friend Weber”(Wilhelm Weber,Professor of Physics at the University of Göttingen)“conducts the experiments on my instructions.As, for example,a clear concept of velocity can be given only through statements on time and space,so in my opinion,the complete determination of the intensity of the Earth’s magnetism requires to specify(1)a weight¼p,(2)a length¼r,and then the Earth’s magnetism can be expressed byﬃﬃﬃﬃﬃﬃﬃp=rp.”After minor adjustment to the units,the experiment was completed in May1832,when the horizontal intensity(H)at Göttingen was found to be1.7820mg1/2mm–1/2s–1(17820nT).The experimentThe experiment was in two parts.In the vibration experiment(Figure G2) magnet A was set oscillating in a horizontal plane by deflecting it from magnetic north.The period of oscillations was determined at different small amplitudes,and from these the period t0of infinite-simal oscillations was deduced.This gave a measure of MH,where M denotes the magnetic moment of magnet A:MH¼4p2I=t20The moment of inertia,I,of the oscillating part is difficult to deter-mine directly,so Gauss used the ingenious idea of conductingtheFigure G2The vibration experiment.Magnet A is suspended from a silk fiber F It is set swinging horizontally and the period of an oscillation is obtained by timing an integral number of swings with clock C,using telescope T to observe the scale S reflected in mirror M.The moment of inertia of the oscillating part can be changed by a known amount by hanging weights W from the rodR. 278GAUSS’DETERMINATION OF ABSOLUTE INTENSITYexperiment for I and then I þD I ,where D I is a known increment obtained by hanging weights at a known distance from the suspension.From several measures of t 0with different values of D I ,I was deter-mined by the method of least squares (another of Gauss ’s original methods).In the deflection experiment,magnet A was removed from the suspension and replaced with magnet B.The ratio M /H was measured by the deflection of magnet B from magnetic north,y ,produced by magnet A when placed in the same horizontal plane as B at distance d magnetic east (or west)of the suspension (Figure G3).This required knowledge of the magnetic intensity due to a bar magnet.Gauss deduced that the intensity at distance d on the axis of a dipole is inversely proportional to d 3,but that just one additional term is required to allow for the finite length of the magnet,giving 2M (1þk/d 2)/d 3,where k denotes a small constant.ThenM =H ¼1=2d 3ð1Àk =d 2Þtan y :The value of k was determined,again by the method of least squares,from the results of a number of measures of y at different d .From MH and M /H both M and,as required by Gauss,H could readily be deduced.Present methodsWith remarkably little modification,Gauss ’s experiment was devel-oped into the Kew magnetometer,which remained the standard means of determining absolute H until electrical methods were introduced in the 1920s.At some observatories,Kew magnetometers were still in use in the 1980s.Nowadays absolute intensity can be measured in sec-onds with a proton magnetometer and without the considerable time and experimental skill required by Gauss ’s method.Stuart R.C.MalinBibliographyGauss,C.F.,1833.Intensitas vis magneticae terrestris ad mensuram absolutam revocata.Göttingen,Germany.Malin,S.R.C.,1982.Sesquicentenary of Gauss ’s first measurement of the absolute value of magnetic intensity.Philosophical Transac-tions of the Royal Society of London ,A 306:5–8.Malin,S.R.C.,and Barraclough,D.R.,1982.150th anniversary of Gauss ’s first absolute magnetic measurement.Nature ,297:285.Cross-referencesGauss,Carl Friedrich (1777–1855)Geomagnetism,History of Gilbert,William (1544–1603)Humboldt,Alexander von (1759–1859)Instrumentation,History ofGAUSS,CARL FRIEDRICH (1777–1855)Amongst the 19th century scientists working in the field of geomag-netism,Carl Friedrich Gauss was certainly one of the most outstanding contributors,who also made very fundamental contributions to the fields of mathematics,astronomy,and geodetics.Born in April 30,1777in Braunschweig (Germany)as the son of a gardener,street butcher,and mason Johann Friderich Carl,as he was named in the certificate of baptism,already in primary school at the age of nine perplexed his teacher J.G.Büttner by his innovative way to sum up the numbers from 1to ter Gauss used to claim that he learned manipulating numbers earlier than being able to speak.In 1788,Gauss became a pupil at the Catharineum in Braunschweig,where M.C.Bartels (1769–1836)recognized his outstanding mathematical abilities and introduced Gauss to more advanced problems of mathe-matics.Gauss proved to be an exceptional pupil catching the attention of Duke Carl Wilhelm Ferdinand of Braunschweig who provided Gauss with the necessary financial support to attend the Collegium Carolinum (now the Technical University of Braunschweig)from 1792to 1795.From 1795to 1798Gauss studied at the University of Göttingen,where his number theoretical studies allowed him to prove in 1796,that the regular 17-gon can be constructed using a pair of compasses and a ruler only.In 1799,he received his doctors degree from the University of Helmstedt (close to Braunschweig;closed 1809by Napoleon)without any oral examination and in absentia .His mentor in Helmstedt was J.F.Pfaff (1765–1825).The thesis submitted was a complete proof of the fundamental theorem of algebra.His studies on number theory published in Latin language as Disquitiones arithi-meticae in 1801made Carl Friedrich Gauss immediately one of the leading mathematicians in Europe.Gauss also made further pioneering contributions to complex number theory,elliptical functions,function theory,and noneuclidian geometry.Many of his thoughts have not been published in regular books but can be read in his more than 7000letters to friends and colleagues.But Gauss was not only interested in mathematics.On January 1,1801the Italian astronomer G.Piazzi (1746–1820)for the first time detected the asteroid Ceres,but lost him again a couple of weeks later.Based on completely new numerical methods,Gauss determined the orbit of Ceres in November 1801,which allowed F.X.von Zach (1754–1832)to redetect Ceres on December 7,1801.This prediction made Gauss famous next to his mathematical findings.In 1805,Gauss got married to Johanna Osthoff (1780–1809),who gave birth to two sons,Joseph and Louis,and a daughter,Wilhelmina.In 1810,Gauss married his second wife,Minna Waldeck (1788–1815).They had three more children together,Eugen,Wilhelm,and Therese.Eugen Gauss later became the founder and first president of the First National Bank of St.Charles,Missouri.Carl Friedrich Gauss ’interest in the Earth magnetic field is evident in a letter to his friend Wilhelm Olbers (1781–1862)as early as 1803,when he told Olbers that geomagnetism is a field where still many mathematical studies can be done.He became more engaged in geo-magnetism after a meeting with A.von Humboldt (1769–1859)and W.E.Weber (1804–1891)in Berlin in 1828where von Humboldt pointed out to Gauss the large number of unsolved problems in geo-magnetism.When Weber became a professor of physics at the Univer-sity of Göttingen in 1831,one of the most productive periods intheFigure G3The deflection experiment.Suspended magnet B is deflected from magnetic north by placing magnet A east or west (magnetic)of it at a known distance d .The angle of deflection y is measured by using telescope T to observe the scale S reflected in mirror M.GAUSS,CARL FRIEDRICH (1777–1855)279field of geomagnetism started.In1832,Gauss and Weber introduced the well-known Gauss system according to which the magnetic field unit was based on the centimeter,the gram,and the second.The Mag-netic Observatory of Göttingen was finished in1833and its construc-tion became the prototype for many other observatories all over Europe.Gauss and Weber furthermore developed and improved instru-ments to measure the magnetic field,such as the unifilar and bifilar magnetometer.Inspired by A.von Humboldt,Gauss and Weber realized that mag-netic field measurements need to be done globally with standardized instruments and at agreed times.This led to the foundation of the Göttinger Magnetische Verein in1836,an organization without any for-mal structure,only devoted to organize magnetic field measurements all over the world.The results of this organization have been published in six volumes as the Resultate aus den Beobachtungen des Magnetischen Vereins.The issue of1838contains the pioneering work Allgemeine Theorie des Erdmagnetismus where Gauss introduced the concept of the spherical harmonic analysis and applied this new tool to magnetic field measurements.His general theory of geomagnetism also allowed to separate the magnetic field into its externally and its internally caused parts.As the external contributions are nowadays interpreted as current systems in the ionosphere and magnetosphere Gauss can also be named the founder of magnetospheric research.Publication of the Resultate ceased in1843.W.E.Weber together with such eminent professors of the University of Göttingen as Jacob Grimm(1785–1863)and Wilhelm Grimm(1786–1859)had formed the political group Göttingen Seven protesting against constitutional violations of King Ernst August of Hannover.As a consequence of these political activities,Weber and his colleagues were dismissed. Though Gauss tried everything to bring back Weber in his position he did not succeed and Weber finally decided to accept a chair at the University of Leipzig in1843.This finished a most fruitful and remarkable cooperation between two of the most outstanding contribu-tors to geomagnetism in the19th century.Their heritage was not only the invention of the first telegraph station in1833,but especially the network of36globally operating magnetic observatories.In his later years Gauss considered to either enter the field of bota-nics or to learn another language.He decided for the language and started to study Russian,already being in his seventies.At that time he was the only person in Göttingen speaking that language fluently. Furthermore,he was asked by the Senate of the University of Göttingen to reorganize their widow’s pension system.This work made him one of the founders of insurance mathematics.In his final years Gauss became fascinated by the newly built railway lines and supported their development using the telegraph idea invented by Weber and himself.Carl Friedrich Gauss died on February23,1855as a most respected citizen of his town Göttingen.He was a real genius who was named Princeps mathematicorum already during his life time,but was also praised for his practical abilities.Karl-Heinz GlaßmeierBibliographyBiegel,G.,and K.Reich,Carl Friedrich Gauss,Braunschweig,2005. Bühler,W.,Gauss:A Biographical study,Berlin,1981.Hall,T.,Carl Friedrich Gauss:A Biography,Cambridge,MA,1970. Lamont,J.,Astronomie und Erdmagnetismus,Stuttgart,1851. Cross-referencesHumboldt,Alexander von(1759–1859)Magnetosphere of the Earth GELLIBRAND,HENRY(1597–1636)Henry Gellibrand was the eldest son of a physician,also Henry,and was born on17November1597in the parish of St.Botolph,Aldersgate,London.In1615,he became a commoner at Trinity Col-lege,Oxford,and obtained a BA in1619and an MA in1621.Aftertaking Holy Orders he became curate at Chiddingstone,Kent,butthe lectures of Sir Henry Savile inspired him to become a full-timemathematician.He settled in Oxford,where he became friends withHenry Briggs,famed for introducing logarithms to the base10.Itwas on Briggs’recommendation that,on the death of Edmund Gunter,Gellibrand succeeded him as Gresham Professor of Astronomy in1627—a post he held until his death from a fever on16February1636.He was buried at St.Peter the Poor,Broad Street,London(now demolished).Gellibrand’s principal publications were concerned with mathe-matics(notably the completion of Briggs’Trigonometrica Britannicaafter Briggs died in1630)and navigation.But he is included herebecause he is credited with the discovery of geomagnetic secular var-iation.The events leading to this discovery are as follows(for furtherdetails see Malin and Bullard,1981).The sequence starts with an observation of magnetic declinationmade by William Borough,a merchant seaman who rose to“captaingeneral”on the Russian trade route before becoming comptroller ofthe Queen’s Navy.The magnetic observation(Borough,1581,1596)was made on16October1580at Limehouse,London,where heobserved the magnetic azimuth of the sun as it rose through sevenfixed altitudes in the morning and as it descended through the samealtitudes in the afternoon.The mean of the two azimuths for each alti-tude gives a measure of magnetic declination,D,the mean of which is11 190EÆ50rms.Despite the small scatter,the value could have beenbiased by site or compass errors.Some40years later,Edmund Gunter,distinguished mathematician,Gresham Professor of Astronomy and inventor of the slide rule,foundD to be“only6gr15m”(6 150E)“as I have sometimes found it oflate”(Gunter,1624,66).The exact date(ca.1622)and location(prob-ably Deptford)of the observation are not stated,but it alerted Gunterto the discrepancy with Borough’s measurement.To investigatefurther,Gunter“enquired after the place where Mr.Borough observed,and went to Limehouse with...a quadrant of three foot Semidiameter,and two Needles,the one above6inches,and the other10inches long ...towards the night the13of June1622,I made observation in sev-eral parts of the ground”(Gunter,1624,66).These observations,witha mean of5 560EÆ120rms,confirmed that D in1622was signifi-cantly less than had been measured by Borough in1580.But was thisan error in the earlier measure,or,unlikely as it then seemed,was Dchanging?Unfortunately Gunter died in1626,before making anyfurther measurements.When Gellibrand succeeded Gunter as Gresham Professor,allhe required to do to confirm a major scientific discovery was towait a few years and then repeat the Limehouse observation.Buthe chose instead to go to the site of Gunter’s earlier observationin Deptford,where,in June1633,Gellibrand found D to be“muchless than5 ”(Gellibrand,1635,16).He made a further measurement of D on the same site on June12,1634and“found it not much to exceed4 ”(Gellibrand,1635,7),the published data giving4 50 EÆ40rms.His observation of D at Paul’s Cray on July4,1634adds little,because it is a new site.On the strength of these observations,he announced his discovery of secular variation(Gellibrand,1635,7and 19),but the reader may decide how much of the credit should go to Gunter.Stuart R.C.Malin280GELLIBRAND,HENRY(1597–1636)BibliographyBorough,W.,1581.A Discourse of the Variation of the Compass,or Magnetical Needle.(Appendix to R.Norman The newe Attractive).London:Jhon Kyngston for Richard Ballard.Borough,W.,1596.A Discourse of the Variation of the Compass,or Magnetical Needle.(Appendix to R.Norman The newe Attractive).London:E Allde for Hugh Astley.Gellibrand,H.,1635.A Discourse Mathematical on the Variation of the Magneticall Needle.Together with its admirable Diminution lately discovered.London:William Jones.Gunter,E.,1624.The description and use of the sector,the crosse-staffe and other Instruments.First booke of the crosse-staffe.London:William Jones.Malin,S.R.C.,and Bullard,Sir Edward,1981.The direction of the Earth’s magnetic field at London,1570–1975.Philosophical Transactions of the Royal Society of London,A299:357–423. Smith,G.,Stephen,L.,and Lee,S.,1967.The Dictionary of National Biography.Oxford:University Press.Cross-referencesCompassGeomagnetic Secular VariationGeomagnetism,History ofGEOCENTRIC AXIAL DIPOLE HYPOTHESISThe time-averaged paleomagnetic fieldPaleomagnetic studies provide measurements of the direction of the ancient geomagnetic field on the geological timescale.Samples are generally collected at a number of sites,where each site is defined as a single point in time.In most cases the time relationship between the sites is not known,moreover when samples are collected from a stratigraphic sequence the time interval between the levels is also not known.In order to deal with such data,the concept of the time-averaged paleomagnetic field is used.Hospers(1954)first introduced the geocentric axial dipole hypothesis(GAD)as a means of defining this time-averaged field and as a method for the analysis of paleomag-netic results.The hypothesis states that the paleomagnetic field,when averaged over a sufficient time interval,will conform with the field expected from a geocentric axial dipole.Hospers presumed that a time interval of several thousand years would be sufficient for the purpose of averaging,but many studies now suggest that tens or hundreds of thousand years are generally required to produce a good time-average. The GAD model is a simple one(Figure G4)in which the geomag-netic and geographic axes and equators coincide.Thus at any point on the surface of the Earth,the time-averaged paleomagnetic latitude l is equal to the geographic latitude.If m is the magnetic moment of this time-averaged geocentric axial dipole and a is the radius of the Earth, the horizontal(H)and vertical(Z)components of the magnetic field at latitude l are given byH¼m0m cos l;Z¼2m0m sin l;(Eq.1)and the total field F is given byF¼ðH2þZ2Þ1=2¼m0m4p a2ð1þ3sin2lÞ1=2:(Eq.2)Since the tangent of the magnetic inclination I is Z/H,thentan I¼2tan l;(Eq.3)and by definition,the declination D is given byD¼0 :(Eq.4)The colatitude p(90 minus the latitude)can be obtained fromtan I¼2cot pð0p180 Þ:(Eq.5)The relationship given in Eq. (3) is fundamental to paleomagnetismand is a direct consequence of the GAD hypothesis.When applied toresults from different geologic periods,it enables the paleomagneticlatitude to be derived from the mean inclination.This relationshipbetween latitude and inclination is shown in Figure G5.Figure G5Variation of inclination with latitude for a geocentricdipole.GEOCENTRIC AXIAL DIPOLE HYPOTHESIS281Paleom a gnetic polesThe positio n where the time-averaged dipole axis cuts the surface of the Earth is called the paleomagnetic pole and is defined on the present latitude-longitude grid. Paleomagnetic poles make it possible to com-pare results from different observing localities, since such poles should represent the best estimate of the position of the geographic pole.These poles are the most useful parameter derived from the GAD hypothesis. If the paleomagnetic mean direction (D m , I m ) is known at some sampling locality S, with latitude and longitude (l s , f s ), the coordinates of the paleomagnetic pole P (l p , f p ) can be calculated from the following equations by reference to Figure G6.sin l p ¼ sin l s cos p þ cos l s sin p cos D m ðÀ90 l p þ90 Þ(Eq. 6)f p ¼ f s þ b ; when cos p sin l s sin l porf p ¼ f s þ 180 À b ; when cos p sin l s sin l p (Eq. 7)wheresin b ¼ sin p sin D m = cos l p : (Eq. 8)The paleocolatitude p is determined from Eq. (5). The paleomagnetic pole ( l p , f p ) calculated in this way implies that “sufficient ” time aver-aging has been carried out. What “sufficient ” time is defined as is a subject of much debate and it is always difficult to estimate the time covered by the rocks being sampled. Any instantaneous paleofield direction (representing only a single point in time) may also be con-verted to a pole position using Eqs. (7) and (8). In this case the pole is termed a virtual geomagnetic pole (VGP). A VGP can be regarded as the paleomagnetic analog of the geomagnetic poles of the present field. The paleomagnetic pole may then also be calculated by finding the average of many VGPs, corresponding to many paleodirections.Of course, given a paleomagnetic pole position with coordinates (l p , f p ), the expected mean direction of magnetization (D m , I m )at any site location (l s , f s ) may be also calculated (Figure G6). The paleocolatitude p is given bycos p ¼ sin l s sin l p þ cos l s cos l p cos ðf p À f s Þ; (Eq. 9)and the inclination I m may then be calculated from Eq. (5). The corre-sponding declination D m is given bycos D m ¼sin l p À sin l s cos pcos l s sin p; (Eq. 10)where0 D m 180 for 0 (f p – f s ) 180and180 < D m <360for 180 < (f p –f s ) < 360 .The declination is indeterminate (that is any value may be chosen)if the site and the pole position coincide. If l s ¼Æ90then D m is defined as being equal to f p , the longitude of the paleomagnetic pole.Te s ting the GAD hy p othesis Tim e scale 0– 5 MaOn the timescale 0 –5 Ma, little or no continental drift will have occurred, so it was originally thought that the observation that world-wide paleomagnetic poles for this time span plotted around the present geographic indicated support for the GAD hypothesis (Cox and Doell,1960; Irving, 1964; McElhinny, 1973). However, any set of axial mul-tipoles (g 01; g 02 ; g 03 , etc.) will also produce paleomagnetic poles that cen-ter around the geographic pole. Indeed, careful analysis of the paleomagnetic data in this time interval has enabled the determination of any second-order multipole terms in the time-averaged field (see below for more detailed discussion of these departures from the GAD hypothesis).The first important test of the GAD hypothesis for the interval 0 –5Ma was carried out by Opdyke and Henry (1969),who plotted the mean inclinations observed in deep-sea sediment cores as a function of latitude,showing that these observations conformed with the GAD hypothesis as predicted by Eq. (3) and plotted in Figure G5.Testing the axial nature of the time-averaged fieldOn the geological timescale it is observed that paleomagnetic poles for any geological period from a single continent or block are closely grouped indicating the dipole hypothesis is true at least to first-order.However,this observation by itself does not prove the axial nature of the dipole field.This can be tested through the use of paleoclimatic indicators (see McElhinny and McFadden,2000for a general discus-sion).Paleoclimatologists use a simple model based on the fact that the net solar flux reaching the surface of the Earth has a maximum at the equator and a minimum at the poles.The global temperature may thus be expected to have the same variation.The density distribu-tion of many climatic indicators (climatically sensitive sediments)at the present time shows a maximum at the equator and either a mini-mum at the poles or a high-latitude zone from which the indicator is absent (e.g.,coral reefs,evaporates,and carbonates).A less common distribution is that of glacial deposits and some deciduous trees,which have a maximum in polar and intermediate latitudes.It has been shown that the distributions of paleoclimatic indicators can be related to the present-day climatic zones that are roughly parallel with latitude.Irving (1956)first suggested that comparisons between paleomag-netic results and geological evidence of past climates could provide a test for the GAD hypothesis over geological time.The essential point regarding such a test is that both paleomagnetic and paleoclimatic data provide independent evidence of past latitudes,since the factors con-trolling climate are quite independent of the Earth ’s magnetic field.The most useful approach is to compile the paleolatitude values for a particular occurrence in the form of equal angle or equalareaFigure G6Calculation of the position P (l p ,f p )of thepaleomagnetic pole relative to the sampling site S (l s ,f s )with mean magnetic direction (D m ,I m ).282GEOCENTRIC AXIAL DIPOLE HYPOTHESIS。

理解黑洞需要一定的想象力和科学知识英语

理解黑洞需要一定的想象力和科学知识英语Understanding Black Holes Requires a Certain Degree of Imagination and Scientific KnowledgeThe vastness of the universe is a constant source of fascination and wonder for human beings. As we gaze up at the night sky, our eyes are drawn to the twinkling stars, the enigmatic planets, and the mysterious celestial bodies that lie beyond our immediate reach. Among these cosmic enigmas, perhaps none have captured the public's imagination more than the phenomenon known as the black hole.Black holes are regions of space-time where the gravitational pull is so immense that nothing, not even light, can escape their grasp. These cosmic behemoths are the result of the collapse of massive stars at the end of their life cycle. When a star runs out of fuel, its core can no longer support the outward pressure that counteracts the inward pull of gravity, causing it to implode and form a singularity – a point in space-time where the laws of physics as we know them break down.Understanding the true nature of black holes requires a certaindegree of imagination and scientific knowledge. On the surface, the concept of a region of space-time where nothing can escape may seem straightforward, but the deeper one delves into the intricacies of black hole physics, the more complex and mind-bending the subject becomes.One of the key aspects of black holes that challenges our intuitive understanding is the concept of the event horizon. The event horizon is the point of no return – the boundary beyond which nothing, not even light, can escape the gravitational pull of the black hole. Visualizing this invisible barrier and comprehending its significance is a task that requires a significant amount of abstract reasoning.Imagine a person standing on the edge of a cliff, gazing out at the vast expanse of the ocean. As they look down, they can see the waves crashing against the rocks below, but they know that if they were to step over the edge, they would be unable to return. The event horizon of a black hole is analogous to this – it is the point at which the gravitational forces become so overwhelming that even the fastest-moving particles in the universe, photons of light, cannot escape.But the event horizon is just the tip of the iceberg when it comes to the complexities of black hole physics. As one delves deeper into the subject, the challenges to our understanding only grow moreprofound.Consider, for example, the concept of time dilation. According to Einstein's theory of general relativity, the passage of time is affected by the presence of strong gravitational fields. As an object approaches the event horizon of a black hole, the rate at which time passes for that object becomes increasingly slowed down relative to an observer outside the black hole. This means that from the perspective of an external observer, the object appears to be frozen in time, gradually becoming fainter and fainter as it crosses the event horizon.Visualizing this phenomenon requires a significant amount of imagination and a deep understanding of the principles of relativity. It challenges our everyday experience of time and forces us to consider the universe from a radically different perspective – one where the familiar laws of physics no longer apply in the same way.Another aspect of black holes that pushes the limits of our imagination is the nature of the singularity itself. At the center of a black hole, where all the matter and energy of the collapsed star is concentrated, the laws of physics as we know them break down completely. This point of infinite density and infinite curvature of space-time is known as the singularity, and it represents the ultimate limit of our current scientific understanding.Trying to comprehend the singularity, a region where the very fabric of space-time is torn apart, is a task that requires a leap of imagination that few can truly make. It forces us to confront the limitations of our own understanding and to grapple with the fundamental mysteries of the universe.Despite these challenges, the study of black holes has been a cornerstone of modern astrophysics and has led to numerous groundbreaking discoveries. Through the use of sophisticated telescopes and advanced mathematical models, scientists have been able to observe the behavior of black holes in unprecedented detail, shedding light on the most extreme and enigmatic phenomena in the cosmos.From the detection of gravitational waves, the ripples in the fabric of space-time caused by the collision of black holes, to the stunning images of the supermassive black hole at the center of the Milky Way, the study of black holes has pushed the boundaries of our scientific knowledge and our understanding of the universe.But perhaps the greatest contribution of the study of black holes is the way it has challenged our fundamental assumptions about the nature of reality. By confronting us with the limits of our own understanding, black holes have forced us to reckon with thepossibility that there are aspects of the universe that may forever remain beyond our grasp.In this sense, the study of black holes is not just a scientific endeavor, but a philosophical one as well. It reminds us that the universe is a vast and mysterious place, and that our knowledge, no matter how extensive, is always a work in progress. It challenges us to remain humble in the face of the unknown and to continue to explore the limits of our understanding with curiosity, wonder, and a willingness to adapt our perspectives as new evidence emerges.Ultimately, the study of black holes is a testament to the power of the human mind to grapple with the most complex and enigmatic phenomena in the universe. It requires a unique blend of imagination, scientific knowledge, and a willingness to embrace the unknown – qualities that have defined the pursuit of scientific discovery since the dawn of human civilization.。

Quantum Mechanics

Quantum MechanicsQuantum mechanics is a branch of physics that studies the behavior of matter and energy at the atomic and subatomic level. It is a fascinating field that has revolutionized our understanding of the universe and has led to the development of many groundbreaking technologies. However, it is also a highly complex and often counterintuitive subject that can be difficult to grasp. In this essay, I will explore the different perspectives on quantum mechanics, including its history, key concepts, and practical applications.One perspective on quantum mechanics is its historical development. Theorigins of quantum mechanics can be traced back to the early 20th century, when scientists began to study the behavior of atoms and molecules. At the time, classical physics was unable to explain many of the phenomena that were observed at the atomic scale, such as the emission and absorption of light by atoms. This led to the development of a new set of principles that would come to be known as quantum mechanics.The key concepts of quantum mechanics are also an important perspective to consider. One of the most fundamental principles of quantum mechanics is the wave-particle duality, which states that particles can exhibit both wave-like and particle-like behavior. This principle is illustrated by the famous double-slit experiment, in which particles are fired at a screen with two slits, producing an interference pattern that can only be explained by the wave-like behavior of particles. Another key concept is the uncertainty principle, which states that it is impossible to know both the position and momentum of a particle with absolute certainty.From a practical perspective, quantum mechanics has led to the development of many groundbreaking technologies. One of the most well-known applications of quantum mechanics is in the field of computing. Quantum computers use the principles of quantum mechanics to perform calculations that would be impossible with classical computers. This has the potential to revolutionize many fields, from cryptography to drug discovery. Another practical application of quantum mechanics is in the field of quantum cryptography, which uses quantum principles to create unbreakable codes for secure communication.Despite its many practical applications, quantum mechanics remains a highly complex and often counterintuitive subject. This can make it difficult forstudents and researchers to fully grasp the concepts and principles of quantum mechanics. However, there are many resources available to help people learn about quantum mechanics, including textbooks, online courses, and research papers. It is important for students and researchers to take the time to fully understand the principles of quantum mechanics, as it is a field that has the potential to shape our understanding of the universe and revolutionize many aspects of our lives.In conclusion, quantum mechanics is a fascinating and complex field that has revolutionized our understanding of the universe and led to the development of many groundbreaking technologies. From its historical development to its key concepts and practical applications, there are many perspectives to consider when studying quantum mechanics. While it can be a challenging subject to fully grasp, there are many resources available to help people learn about quantum mechanicsand its many applications. As we continue to explore the mysteries of the universe, quantum mechanics will undoubtedly play a key role in shaping our understanding of the world around us.。

The Properties of Neutron Stars

The Properties of Neutron Stars IntroductionNeutron stars are the remnants of supernova explosions, they are some of the most extreme objects in the universe. They are incredibly dense, with a mass comparable to the sun, but a size comparable to a city. In this article, we will explore the properties of neutron stars.FormationNeutron stars are formed when a massive star runs out of fuel and undergoes a supernova explosion. During the supernova, the core of the star collapses, creating an incredibly dense object known as a neutron star. The collapsed core is composed mainly of neutrons, which are tightly packed together due to the intense gravitational forces.SizeNeutron stars are incredibly small compared to normal stars, with a typical radius of around 10 km. This makes them incredibly dense, with a mass several times that of our sun, compressed into a volume the size of a city.DensityThe density of a neutron star is incredible, with an average density of around 10^17 kg/m^3. This is around 1 billion times denser than the density of water. Due to their extreme density, neutron stars have a strong gravitational field, which can distort nearby spacetime.Magnetic FieldsNeutron stars are known for their incredibly strong magnetic fields, which can be trillions of times stronger than the Earth's magnetic field. These magnetic fields can create intense radiation, including X-rays and gamma rays, which can be detected by telescopes.RotationNeutron stars can rotate incredibly quickly, with some rotating hundreds of times per second. This rapid rotation is due to their small size and high density, which allows them to conserve their angular momentum as they collapse.Neutrino EmissionNeutron stars are also known for emitting neutrinos, which are subatomic particles that can pass through matter almost unimpeded. These neutrinos are created during the supernova explosion that forms the neutron star, and can carry away up to 99% of the energy produced.ConclusionNeutron stars are some of the most extreme objects in the universe, with incredible properties that make them fascinating to study. Their small size and incredible density make them a unique laboratory for studying the laws of physics under extreme conditions. As we continue to explore and study these objects, we will learn more about the mysteries of the universe.。

英语科普小知识黑洞的诞生

A new kind of cosmic flash may reveal something never seen before: the birth of a black hole. When a massive star exhausts its fuel, it collapses under its own gravity and produces a black hole, an object so dense that not even light can escape its gravitational grip. According to a new analysis by an astrophysicist（天体物理学家） at the California Institute of Technology (Caltech), just before the black hole forms, the dying star may generate a distinct burst of light that will allow astronomers to witness the birth of a new black hole for the first time.Tony Piro, a postdoctoral scholar at Caltech, describes this signature light burst in a paper published in the May 1 issue of the Astrophysical Journal Letters. While some dying stars that result in black holes explode as gamma-ray bursts, which are among the most energetic phenomena in the universe, those cases are rare, requiring exotic circumstances, Piro explains. "We don't think most run-of-the-mill black holes are created that way." In most cases, according to one hypothesis, a dying star produces a black hole witho ut a bang or a flash: the star would seemingly vanish from the sky -- an event dubbed an unnova. "You don't see a burst," he says. "You see a disappearance."But, Piro hypothesizes, that may not be the case. "Maybe they're not as boring as we thought," he says.According to well-established theory, when a massive star dies, its core collapses under its own weight. As it collapses, the protons and electrons that make up the core merge and produce neutrons. For a few seconds -- before it ultimately collapses into a black hole -- the core becomes an extremely dense object called a neutron star, which is as dense as the sun would be if squeezed into a sphere with a radius of about 10 kilometers (roughly 6 miles). This collapsing process also creates neutrinos, which are particles that zip through almost all matter at nearly the speed of light. As the neutrinos stream out from the core, they carry away a lot of energy -- representing about a tenth of the sun's mass (since energy and mass are equivalent, per E = mc2).According to a little-known paper written in 1980 by Dmitry Nadezhin of the Alikhanov Institute for Theoretical and Experimental Physics in Russia, this rapid loss of mass means that the gravitational strength of the dying star's core would abruptly drop. When that happens, the outer gaseous（气态的） layers -- mainly hydrogen -- still surrounding the core would rush outward, generating a shock wave that would hurtle through the outer layers at about 1,000 kilometers per second (more than 2 million miles per hour).Using computer simulations, two astronomers at UC Santa Cruz, Elizabeth Lovegrove and Stan Woosley, recently found that when the shock wave strikes the outer surface of the gaseous layers, it would heat the gas at the surface, producing a glow that would shine for about a year -- a potentially promising signal of a black-hole birth. Although about a million times brighter than the sun, this glow would be relatively dim compared to other stars. "Itwould be hard to see, even in galaxies that are relatively close to us," says Piro.But now Piro says he has found a more promising signal. In his new study, he examines in more detail what might happen at the moment when the shock wave hits the star's surface, and he calculates that the impact itself would make a flash 10 to 100 times brighter than the glow predicted by Lovegrove and Woosley. "That flash is going to be very bright, and it gives us the best chance for actually observing that this event occurred," Piro explains. "This is what you really want to look for."一种新的宇宙闪光可能会发现以前从未见过的东西：一个黑洞的诞生。

如何理解科学是把双刃剑英语作文

如何理解科学是把双刃剑英语作文Title: Understanding Science as a Double-edged SwordScience has been hailed as the beacon of human progress and innovation, leading to groundbreaking discoveries and advancements in various fields. From improving healthcare and nutrition to exploring outer space, the impact of science on society cannot be overstated. However, it is important to recognize that science is a double-edged sword, capable of both positive and negative consequences.On the one hand, science has revolutionized our lives in countless ways. Advancements in medicine have led to longer life expectancy and better quality of life for millions of people around the world. Vaccines, antibiotics, and surgical procedures have eradicated diseases that were once deadly and untreatable. In addition, technology and engineering have enabled us to travel to the moon, communicate across continents in an instant, and access virtually limitless information at our fingertips.Furthermore, scientific research has shed light on the mysteries of the universe and deepened our understanding of the natural world. The discoveries of evolution, genetics, and the laws of physics have transformed our perception of life and theuniverse. By studying the cosmos, we have learned about the origins of the universe and our place in it.However, science also has the potential to be used for harm. The same technology that has improved our lives can also be weaponized and used for destructive purposes. Nuclear weapons, biological warfare, and cyber attacks are all examples of how science and technology can be misused to cause harm and destruction. Moreover, the pursuit of scientific knowledge can sometimes lead to unintended consequences, such as environmental degradation, climate change, and the depletion of natural resources.In addition, scientific advancements have raised ethical and moral dilemmas that society must grapple with. Issues such as genetic engineering, artificial intelligence, and cloning raise questions about the limits of scientific progress and the implications for humanity. For example, the ability to manipulate genes and create designer babies raises concerns about the potential for eugenics and discrimination based on genetics.Ultimately, it is up to society to harness the power of science for the greater good and to mitigate its potential risks. This requires a responsible approach to scientific research and innovation that considers the ethical, social, and environmentalimplications of new technologies. By promoting scientific literacy, critical thinking, and ethical standards, we can ensure that science remains a force for progress and enlightenment.In conclusion, science is a double-edged sword that has the power to transform society for the better or for the worse. By understanding the potential benefits and risks of scientific advancements, we can navigate the complexities of the modern world and ensure that science serves the greater good. As we continue to push the boundaries of knowledge and innovation, let us be mindful of the responsibilities that come with wielding this powerful tool.。

体力活动对学业成绩影响的研究进展

令综述报告|ZONGSHUBAOGAO体力活动对学业成绩影响的研究进展Reserrcli Progress on the Effect of Physicii Activity onAcademic Performance朱晨,曹若凡Zhu Ches,Cao Ruofan摘要:研究目的:探讨体力活动对中小学生学业成绩的影响，为促进中小学生体力活动提供理论支撑;找出现有研究的不足，为学者提供研究方向。

研究方法：运用文献资料法，在wed Obiexe核心合集检索到2014-2020年297篇英文文献以及中国知网搜索到2篇国內文献。

在总结现有文献的基础上，运用逻辑分析法，探讨体力活动对中小学生学业成绩的影响。

结果与分析:大部分学者表明体力活动会对中小学生学业成绩产生积极的影响，且体力活动与学业成绩呈较低的正向相关关系。

与LPV相比，MPV、MVPV是研究热点，且对学业成绩的影响更大。

不同体力活动的组织形式、不同运动类型都可能会对学业成绩产生不同的影响。

但从研究结果来看，多是积极的。

结论与建议:本研究表明学生进行适当的体育活动能够提高学业成绩。

学校可通过不同的组织形式发展多种不同类型中高强度体力活动提高学生学业成绩。

关键词：中小学生；体力活动；学业成绩Abstract:Purpose,To expOre the ePect of physical activity on the academic peWormance of primay and middleschool students p”provide theorePcai support for the promotion of physical activity of primay and seconday schoolstudents Jo find out the deficiexcics of6X81111"reseoch,/d to provide research directions for scholars.Methobs:Using the literature methob,297Eng/sh docnmexts from2014to2020arc retrieved from the core collection of wedof sciense and7domestic docnmexts arc seoched by CNKF on the basis of summarizing the existing literatures.Logical an/ysis is used to explore the ePect of physical activity on the acadermc peWormance of primay andmiddle school students.Results:Most scholos inhicawd that physical activity will have a positive impact on theacademic peWormance of primay and middle school students；and physical activity and acadermc peWormance havea Ow positive pared with LPV,MPV and MVPV arc research hotspots a nd have a yreater impacton academic performance.Di/erext forms of physical activity and di/erext上；”-of sports may have di/erextePects on academic peWorm/ce.Jud/ng from the research results,it is mostly positive•Conclusions:TUis studyshows that students；appropUaW physical activity can improve academic peWormance.Schools can deveOp avariety of di/erext tyycs of high-intensity physical ackviOcs through di/erext oryanizationai forms to improvestudents'academic peWormance.Key WO as：e/mextay and middle school students；physical activity；academic peWormance中图分类号:G27文献标识码:A文章编号：705-0256(2051)05-0198-3doi：14.19379/j.uh/O/x1005-4256605).05.075前言体育对不同的主体，例如国家、社会、个人等有不同的功能，且还有许多功能尚待探索”对于中小学生来说，他们处于身体发展的关键时期，同时面临着巨大的课业负担与升学压力”学校和家长却更加重视学生学习情况而轻视了体力活动状况”众所周知,青少年体力活动不足是一个世界性问题”如果发展体力活动能够对学业成绩产生积极影响，问题就迎刃而解了”然而近年来参与体力活动对学业成绩的影响众说纷纭”9研究目的本文探讨中小学学生的体力活动对学业成绩的影响，为促进儿童青少年体力活动提供理论支撑;总结现有研究的不足,为未来研究提供发展方向”5研究方法5.1文献资料法在wed of sciense核心合集以及中国知网搜索文献资料”在wed of sciense核心合集使用高级搜索:第一次检索式为TS =J achemio achievement”，第二次检索式为TS="physic/activity or exercise(,第三次检索式为TS=“student”,用逻辑词“nd”连接三个检索式，共搜索到297篇英文文献”在中国知网以“体力活动”或含“体育锻炼”并且“学业成绩”为主题搜索到在核心期刊发表的7篇文献”这些研究成果为本文提供了详实而又丰富的文献基础”56逻辑分析法在研究现有文献的基础上,总结体育锻炼对学生学业成绩产生的影响，为促进中小学生体力活动提供理论支撑;找出不足，为学者提供研究方向”第一作者简介:朱晨(1990-)，女，山西太原人，在读硕士研究生，研究方向:大众健身与原理”作者单位:山西师范大学体育学院，山西临汾601906SpoU Col O ye of Shaaxi Nown/Univewity,Linfes601966,Shauxi,Chixa.BULLLTIC OF SPORT SCANCE AND TECHNOLOGYVo).25.NO.0.0201综述报告|ZONGSHUBAOGAO令3结果与分析3.I体力活动对学业成绩的影响的文献述评体力活动(PA)是指任何由骨骼肌收缩引起的导致能量消耗的身体运动”体育锻炼是PA的下位概念”学业成绩(AA)通过平均成绩点数(GPA)、考试分数、考试通过率等来反映”3.1.1体力活动与学业成绩的关系大部分学者表明体力活动会对中小学生的学业成绩呈正相关关系，但关联程度较低”来自美国的一项横断面研究显示，学校体育活动参与度与初中与高中学业成绩有关,总效应系数为2.225”一项来自智利的调查研究显示,每周进行学校体育锻炼时间最多的小学生(每周4小时以上)在语言和数学方面的AA更好”此研究把学业成绩进一步细化，分为各个学科的成绩”一项来自上海的调查研究报告，小学和初中学生参加体力活动的时间越长、次数越多，对主科成绩及总分有相关关系”PA会促进有氧耐力的提高，有氧耐力可以促进AA的提高,那么有氧耐力(AF)是否可以做为中介变量影响二者关系？答案是肯定的”Kyan A发现在男生中，AF充当了PA与AA 的中介变量，而在女生中,AA、AF与PA均不存在相关关系”[81/0X1™K指出PA与数学成绩的关系通过AF调节，但是PA、有氧体适能与阅读考试分数、拼写考试分数无关”PA与数学成绩相关，与体育锻炼会影响BDNF和血管内皮生长因子(VEGF)从而影响学生的空间联想能力的研究结果一致”因为较好的空间思维会提高学生的数学及物理的学业成绩”其他中介变量(mediator)还有以社会情感能力为代表的社会心理因素变量、以睡眠质量为代表的健康因素变量、以执行功能为代表的心智能力变量等，是对Tomporowshi学者理论模型的继承与创新”还有许多中介变量等待着学者的开发与证实”为了使研究结果具有科学性与真实性,实验研究或者调查研究常常还会用到调节变量(moderator)”影响两者关系的调节变量有学生年龄、性别、年级，父母的教育水平、收人等”3.7.2体力活动对学业成绩的影响不同体力活动组织形式、运动强度、运动项目会对学业成绩产生的不同的影响”“运动中学习”是国外新兴的一种课堂模式”MeWae实验研究发现4年级小学生在数学课学习乘法表时进行MPA(每次20分钟，每周三次,6周)，可能有助于促进学习”在学生考试前的体力活动干预可能对学业成绩的产生不同的影响”Howie E K以PA与AA的时间-剂量效应关系研究为中心，比较了4-5年级学生5、10、20分钟的课间中高强度有氧运动与9分钟的课间静坐对学习成绩影响的差异”与非运动课间休息相比，进行12分钟和22分钟的课间体育运动可以适当提高学生的数学成绩”体力活动后与举办考试的间隔时间也会影响AA”Philips D研究发现8年级学生在高强度(74-85%)体育锻炼34分钟以后，数学考试成绩比其他情况(PA后45分钟、静坐行为后32分钟、静坐行为后45分钟)高17-22%”MPV、MVPA甚至VPA均会对学业成绩产生影响”Duncan M J发现与高强度运动组、休息组相比,MPV对阅读成绩的提升更明显”Ludass D R研究成果为体育课进行MVPA会对数学成绩产生较小的积极影响”促进学生参与学校运动，包括各种团队运动和个人运动,可能是提高学生的学业成绩的有益方法,运动种类可以包括有氧运动、抗阻运动、力量训练等”更好的有氧适能与更大的海马体体积、更大的眶额叶皮层面积有关,这为有氧运动可以提高学业成绩提供了依据”Hpveus采用了交叉设计的实验方法，发现抗阻运动比非运动有更高的数学成绩,但是参与有氧运动学生的数学成绩与非运动相比没有显著性差异”由于实验中的强度是由RPE测量的，有氧运动和阻力运动的强度有可能无法精确匹配”所以与大部分实验中有氧运动对学业成绩影响的结果不一致”3.3.8特殊群体学生的适用性对特殊群体的学生主要集中在对自闭症学生(ASD)的研究中”Nadutis S N研究成果为:与普通群体一致，体力活动对ASD儿童学业成绩具有促进作用”以慢跑等简单的方式进行体育锻炼可能对提高诊断为ASD的学生的学习成绩有效”有氧体适能的变化也可能会带来ASD儿童学习成绩的变化”现有研究对其他特殊群体学生的关注较少,学者可以拓宽研究的对象”3.7体力活动影响学业成绩的机制体力活动提高学习成绩的生理机制的假说有:通过增加脑血流量和供氧率;改变下丘脑-垂体肾上腺轴激素的释放;增加神经营养因子(尤其是神经营养因子BDNF)，增加白质量和神经连接性,改善学习和记忆功能;体育锻炼可以促进细胞稳定性并减轻压力对身体的负面影响,减少自由基”另外，生物学和神经科学的证据表明，体育活动通过刺激编码激活认知资源的分配，并促进更快的认知过程,并且一项荟萃分析显示,年龄会调节运动与认知之间的效应大小”现有研究只是提供了几种生理机制的假说，并没有形成确切的证据”3.8目前研究不足及未来方向3.8.3机制研究是基础体力活动影响学业成绩的机制尚不明确，只是提供了几种可能性”我们需要“追本溯源”，“源头”是基础”未来学者可以深入研究体力活动对学业成绩产生促进作用的机制”3.8.7剂量-效应研究是重点关于体力活动对学业成绩影响的剂量-效应的研究较少，还是集中在体力活动对学业成绩的影响的质的研究上，加大对量的研究是大势所趋”两者剂量-效应研究可以包括体力活动总量、强度、时间、频率的“剂量”对学业成绩的“效应”的影响”3.8.8中介变量研究是补充张伟霞的一研究结果显示,体育锻炼对学业成绩的调节作用仅有2.87,提示我们不能忽略中介变量的作用”目前关于中介变量研究的研究还较为局限，学者们在未来的研究中应该拓宽思路，探索更多的中介变量以推动研究向科学化发展”324结果综上所述，大部分学者表明体力活动会对中小学生学业成绩产生积极的影响，且体力活动与学业成绩呈较低的正向相关关系”、.与LPV相比,MPV、MVPV是研究热点，且对学业成绩的影响较大”不同体力活动的组织形式、不同运动类型都可能会对学业成绩产生不同的影响”但从研究结果来看，多是积极的”22两者关系的中介变量包括以有氧耐力为代表的身体素质变量、以社会情感能力为代表的社会心理因素变量、以睡眠质量为代表的健康因素变量、以执行功能为代表的心智能力变量等”这些变量均较小程度参与改善了学业成绩体育科技文献通扌收咛第25卷第2期2027年2月令综述报告|ZONGSHUBAOGAO3.影响两者关系的协变量有学生年龄、性别、年级，父母的教育水平、收人等”为了使研究更加严谨，学者应加大对协变量的关注”4(对孤独症儿童来说,体力活动同样能够提高学业成绩”5.影响体力活动与学业成绩的关系的生理学机制有细胞学、神经科学、认知科学等方面”6(现有国内外文献对机制的研究不够深入,缺少剂量-效应研究，中介变量研究范围较窄”7(相比于国外文献我国研究数量较少，研究内容、研究方法比较单一”4结论与建议本研究充分表明了中小学生进行适当的体育活动能够显著提高学业成绩”学生应该适当增加体力活动时间，不仅为了健康(生理健康、心理健康)而且对学业成绩也有益处”体力活动的参与度与家庭和学校的支持有关”学校可通过不同的组织形式发展多种不同类型中高强度体力活动提高学生学业成绩”体育课与课间时间应该充分利用”家长可以宣传“终身体育”的理念，增加学生校外体育运动”借助我国《健康中国2232规划纲要》的契机，把发展学生体育活动落到实处”未来学者可以深入研究机制问题、加大对剂量效应研究的关注，拓宽中介变量研究的范围”国内学者应该更加重视体力活动对学业成绩影响的研究，创新研究内容,借鉴国外研究方法”参考文献：[1]Wretmao C J.School SpoUs PaUicipatiou and Acabemte Achievemeotiu Middle and High School[J].Jourual of The Society for Social Worf and Research,2657,8(5):399-426.[0]CorreOurrows P,B upows R,Ibaceta C V,etad Physically activeChipao school kids peUomi better iu language and mathematics J]•He/th PromoXor Intema/onal,2657,30(0)：205-259.J]李凌姝•身体活动对我国中小学生学业成绩影响及其中介变量的研究[D].华东师范大学,2618.[4]Loreuz K A,Styliauou M,Moore S,etW.Does fitoess make/egrabe?The wlationship beteees elemed/rp s/UeUs'physical I/ess and academic grabes-J].Health EducaOop Jouru/,2657.77(3): 370-312.J]Kyao A,TaUOura M,Miyagi M.Mediating elect of aerobic fitoess or the associatior beteees physic/achvity and acabemte achieve-mest among abcOesceUs:A cross-sectional s/Uy iu Okinawa.Japo [J].Coumal of SpoUs Sciences,2618：8-8.[6]Lambourue K,Hoses D M,Szabo A N,e/P Indirect and direct wla-tiors bePees aerobic fitness, physical activity:od academic achieve-mest iu elemestw”school stuOests[J].Mestal He/th&Physic/ Activity,2613,6(5)：875-571.[7]Meloie,Vetter,Heles,e/1.LeoUng"Math or the Move":EEec-tivesess of a Combiued Numeracy and Physical Achvip Prou a m for PUmarp School Childws.J]•Coumal of Physic/Activity&Health, 2618.[8]Howie E K, Schatz J,Pate R R.Acute Effects of Classroom ExerciseBreaks or Executive Fuoctior od Ma/PeUounaoce:A Dose-Response Study J].Research Quoterly for Exercise&SpoU.[9]Phillips D,Hanoor J C,Castelli D M.Effects of Vigorous InteusipPhysical Activity or Mathematics Test PeUounaoce[J].Joumal of Teaching iu Physical EducatWo,263,34(3)：347-362.[17]Duocao M J,Jobnsor A.The effect of diPeeng intessikes of acutecycling or preabcCesceot academic achievement-J].Europeau Journal of SpoU ScPoce,263,14(5):079-24.[15]Ludaos D R,Beauchamp M R,Diallo T M,etW.School Physical Activity IntewesUor Effect or Adolescests PeUounaoce iu Mathematics.[J]•Medicine od Scieoce m Sports od Exercise,263,50(10)：9420-2557.[12]Brablep J,Keaue F,Crawford S.School Sport and Academic A-chievemeU J].Coumal of School He/th,273,83(5)8-3. [13]Hamesor A,Houor J C,Brusseau T A,e/d Acute Exercise andAcademic Achievemest iu Middle School StudeUs-J].Internatior/Joumal of EovirormentW Research od PuUlie Heal/,2617,17(19)0[3]NakuUu S N,GuUerrea G.Effect of Physical ActiPty or AcademicEnoagemeot and Executive Fuocticwinv iu Childres with ASD.[J].School PuchWcu Review,2617,22(0)：577-14.[13]Nicholsor H,Kedle T J,Bray M A, e/d The effects of aUecedeotppysical achvip or the academic edgagemest of childrep with auUsmspectrum disorUer[J].Psycholoaa iu the Schools,2615,48(2)：38-013.匕7]BULLLTIC OF SPORT SCILNCEAND TECHNOLOGYVol.29.NO.2.2021。

自然界的超螺旋结构

自然界的超螺旋结构英文回答：The superhelical structure is a common phenomenon found in nature, especially in biological systems. This structure is characterized by a coiled or twisted shape, which can be observed in molecules such as DNA, proteins, and even some types of polymers.One of the most well-known examples of a superhelical structure is the double helix shape of DNA. The DNA molecule is composed of two strands that twist around each other to form a double helix. This coiled structure is essential for the storage and replication of genetic information.In proteins, the superhelical structure can be observed in the arrangement of alpha helices and beta sheets. These secondary structures can twist and coil around each other, giving rise to complex three-dimensional shapes that arecrucial for the function of the protein.Superhelical structures are also found in some types of polymers, where the molecular chains can twist and coil around each other, leading to unique mechanical and physical properties.Overall, the superhelical structure is a fascinating phenomenon in nature that plays a crucial role in the function and behavior of various biological and chemical systems.中文回答：超螺旋结构是自然界中常见的现象，特别是在生物系统中。

阅读方法论之技巧指导 (2)

阅读方法论之技巧指导在阅读教学讨论当中，语言学家发觉，一篇文章中不熟悉的单词占全文词汇总量的比例只要掌握在8%以内，是肯定不会影响到全文任何观点的理解的。

Myth 2：专出名词，尤其是涉及全文主题的专出名词必需熟悉？这一问题牵涉到了一系列问题，那就是什么叫做熟悉专出名词？从英到汉的翻译叫做熟悉？还是知道专出名词的特征叫做熟悉？读者请想想看，我们在阅读理解中有没有遇到过这样的问题提法：What is sedge root？我想没有，由于这种问法是在问专出名词的.翻译。

我们遇到的更多是这样的一些问法：According to the passage，which of the following statements about sedge root is true？What can be inferred from the passage about sedge root？这些问题的提法却是在问专出名词的文中阐述特征。

我们再从文章本身对这个问题做出进一步的分析。

假设原文有这样一句话：Sedge root，a woody fiber that can be easily separated into strands， is essential to basketry production。

请问sedge root的中文翻译莎草的根能够关心我们解决阅读理解题目吗？我想很难！真正能够关心我们解决阅读理解题目的应当是这样的文字a woody fiber 和定语从句中的文字部分can be easily separated into strands 。

通过上述的分析，想必大家已经特别清晰地熟悉到过去我们舍命去死记硬背专出名词的中文释义是多么愚蠢的行为。

由于真正的熟悉应当是对特征的熟悉，所以Sodium Caseinate和它的释义酪蛋白酸钠对我们而言是一样的毫无意义，究竟我们对它们都没有任何的概念。

Myth 3：我们可以从上下文中猜出单词的释义？笔者认为从上下文中猜出单词的释义是不现实的。

科技英语形核功

科技英语形核功Nuclear fusion refers to the process of releasing energy by combining the nuclei of atoms. This scientific achievement has been a hot topic in the field of technology and energy for several decades. Fusion power has the potential to be a game-changer in the energy industry, as it offers a sustainable and virtually unlimited source of clean energy. The basic principle behind nuclear fusion is to replicate the same process that powers the sun. In the sun's core, hydrogen nuclei collide with such high energy that they combine and form helium, releasing an enormous amount of energy in the process. Scientists have been attempting to recreate this process on Earth to harness its energy potential.One of the main challenges in achieving nuclear fusion is creating and maintaining the extreme conditions required for the fusion reaction to occur. At extremely high temperatures, around 100 million degrees Celsius, hydrogen isotopes, such as deuterium and tritium, are heated to the point where they form a plasma state. This plasma is then confined and isolated from the surrounding environment using high magnetic fields.There are two main approaches to achieving controlled fusion reactions: magnetic confinement fusion (MCF) and inertial confinement fusion (ICF). MCF involves using magnetic fields to contain and manipulate the plasma, while ICF involves compressing small pellets of fusion fuel with powerful lasers. Both approaches aim to create an environment where the fuel ions can overcome their natural repulsion due to their positive electric charge and come close enough for the strong force to bind them together, releasing energy.Currently, the most well-known and advanced fusion experiment is the International Thermonuclear Experimental Reactor (ITER) in France. ITER is a collaborative project involving 35 countries that aims to demonstrate the feasibility of fusion power. It uses the MCF approach and is designed to produce 500 megawatts of fusion power for short bursts, equivalent to the power generated by a medium-sized coal-fired power plant. ITER is expected to be completed by 2025 and will serve as a stepping stone towards the development of commercial fusion power plants.The advantages of nuclear fusion are numerous. Firstly, fusion power does not produce greenhouse gas emissions or radioactive waste, making it an environmentally friendly andsustainable energy source. Secondly, fusion fuel, such as deuterium, is abundant and can be extracted from seawater, ensuring a virtually limitless supply. Additionally, fusion power plants would be inherently safe, as the fusion reaction can be easily controlled and any disruptions would cause the reaction to stop automatically.However, the road to practical fusion power is still filled with challenges and obstacles. The biggest challenge is achieving a net energy gain, meaning that the energy produced by the fusion reaction exceeds the energy input required to sustain it. To achieve this, scientists must find a way to sustain the plasma at high enough temperatures and for long enough periods of time. They must also develop advanced materials that can withstand the extreme conditions inside a fusion reactor.Despite these challenges, the potential benefits of nuclear fusion make it a promising avenue of research. If successful, fusion power could revolutionize the energy industry, providing a clean and sustainable alternative to fossil fuels. It has the potential to drastically reduce our dependence on nonrenewable energy sources and mitigate the harmful effects of climate change.In conclusion, nuclear fusion is a promising technology with the potential to solve many of the world's energy and environmental challenges. While significant progress has been made, there is still much work to be done before fusion power becomes a commercially viable option. However, with continued scientific research and international collaboration, practical fusion power may be within our reach in the near future.。

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Hughes, Rakowski, Burrows & Slane 2000
Supernovae from Massive Stars produce most of the elements from Oxygen to Calcium and half of the Iron/Cobalt/Nickel. They may also be responsible for the r-process.
Lphoton W 10 ~10 Lsun ~LGalaxy
36 ~10
Kepler, De Stella Nova in Pede Serpentarii, (1606) W.R. Hix (ORNL/ U. Tenn.) CNS Summer School, August 2007
Supernova Taxonomy
log Abundance (Si=6)
8 6
Si S Ca
Fe
0
20
40
60
80
100
120
140
160
180
200
Atomic Mass
W.R. Hix (ORNL/ U. Tenn.) CNS Summer School, August 2007
From where did our atoms come?
One proposed model is a collaspar, where an accretion disk forms around a newly formed black hole in a failed supernova (M>?30 solar masses), producing a jet which we see as the GRB.
Cassiopeia A
X-ray (NASA/CXC/SAO)
Optical (MDM Obs.)
Radio (VLA)
Infrared (ISO)
1044 J (1028 MegaTons TNT) of Kinetic Energy into the ISM
Ejecta Rich in Heavy Elements
SN 2006gy possibly pair instabilty SN
Supernova at 320 Years Old
Cassiopeia A
X-ray (NASA/CXC/SAO)
Optical (MDM Obs.)
Radio (VLA)
Infrared (ISO)
Supernova at 320 Years Old
Cooling
Proto-Neutron Star U. Tenn.)
CNS Summer School, August 2007
Supernovae Modeling is Ongoing
Bruenn, …, Hix, … (2006)
New idea! Explosions occur when Oxygen layer reaches shock, driven by interplay of neutrino heating, hydrodynamic instabilities and nuclear burning.
Supernova Taxonomy
Observationally, there are 2 types (and 7 subtypes) based on their spectra and light curves. Physically, there are 2 3 4 mechanisms, thermonuclear (white dwarf), core collapse (massive star), collapsar (very massive star), pair (very very massive star)
4 -1 2
-2 0 -3 -2
+ +
Te/I Ba
Os/Ir/Pt
Pb
0
80 20
100 40
60 120 80
140 100
120 160 140
180 180 200 160 200
CNS Summer School, August 2007
Atomic Mass Atomic Mass
W.R. Hix (ORNL/ U. Tenn.)
Cappellaro & Turatto 2001
6 from 1, 1 from another
The core collapse mechanism results in supernovae with quite varied spectra and light curves because of the variations in the stellar envelope which surrounds the central engine. In contrast, the Type Ia SN are remarkable similar, suggesting a mechanism with little variation.
Kepler, De Stella Nova in Pede Serpentarii, (1606) W.R. Hix (ORNL/ U. Tenn.) CNS Summer School, August 2007
Historical Supernovae
Name RX J1713.7-3946 G327.6+14.6 Crab Nebula 3C 58 Tycho Kepler Cassiopeia A S Andromedae Shelton Year 393 1006 1054 1181 1572 1604 1668 1885 1987
✴ Nucleosynthesis
Iron-peak
56Ni,57Ni, 44Ti,
etc.
p-process r-process
✴ Nuclear Matter
Stardust School, (JPL-Caltech/NASA) August 2007
Lecture Schedule
1. Nuclear Physics for Astrophysics 2. Lives of Stars 3. Core Collapse Supernovae
a)What role to CC SN play in cosmic nuclear evolution? b)How does nuclear physics affect the supernova explosion and the resulting nucleosynthesis?
Cappellaro & Turatto 2001
Supernova Taxonomy
Observationally, there are 2 types (and 7 subtypes) based on their spectra and light curves.
Cappellaro & Turatto 2001
Neutron Star Remnants
Core Collapse SN explosion also leaves behind a Neutron Star or Black Hole.
W.R. Hix (ORNL/ U. Tenn.) CNS Summer School, August 2007
W.R. Hix (ORNL/ U. Tenn.) CNS Summer School, August 2007
Supernova and γ-ray Bursts
Recent observations have tied some peculiar, hyperenergetic Type Ic supernovae (called hypernovae by some) to GRBs.
12 2 H 10 1 8
0 6
He NO C + Ne + +
Solar s- and r- Process Abundances Solar Abundances
Ba Te/I
Si S Ca Fe
log Abundance Log Abundance (Si=6) (Si=6)
Pb Os/Ir/Pt
W.R. Hix (ORNL/ U. Tenn.) CNS Summer School, August 2007
Nuclear Physics in Supernovae
✴ Core Collapse Mechanism
Nuclei present during collapse/above shock Nuclear EOS
Subaru and Keck (NAOJ)
(SST/HST/CXO/NASA)
Integral (ESA)
Nuclear Physics of Core Collapse Supernova
W.R. Hix (ORNL/UTK)
SNO W.R.
Hix (ORNL/ U. Tenn.)
CNS Summer
CNS Summer School, August 2007
Textbook Supernova
ν-Luminosity Matter Flow
Heating
νe + n → p + e_ νe + p → n + e+
Shock
νe + n ← p + e_ νe + p ← n + e+