Chapter 3 Radioactive Decay and Growth

(完整版)2018新能源专业英语编辑整理：尊敬的读者朋友们：这里是精品文档编辑中心，本文档内容是由我和我的同事精心编辑整理后发布的，发布之前我们对文中内容进行仔细校对，但是难免会有疏漏的地方，但是任然希望（(完整版)2018新能源专业英语）的内容能够给您的工作和学习带来便利。

同时也真诚的希望收到您的建议和反馈，这将是我们进步的源泉，前进的动力。

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(完整版)2018新能源专业英语编辑整理:张嬗雒老师尊敬的读者朋友们：这里是精品文档编辑中心，本文档内容是由我和我的同事精心编辑整理后发布到文库,发布之前我们对文中内容进行仔细校对，但是难免会有疏漏的地方,但是我们任然希望 (完整版)2018新能源专业英语这篇文档能够给您的工作和学习带来便利。

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新能源专业英语1。

Put the following phrase into English.Unit 11。

温室效应the greenhouse effect2。

可再生能源renewable energy3.太阳能电池solar cell4。

风力发电系统wind turbine system5。

核能nuclear energy6。

海洋能ocean energyUnit 21.辐射度 irradiance2。

负载 load3。

耐候性weather fastness4.光电效应photoelectric effect5.光生伏打效应photovoltaic effectUnit 31。

风电场wind farm2.装机容量installed capacity3.涡轮机turbine4.水泵water pumping5.风光互补wind and photovoltaic hybrid power6。

大学物理英语教材Unit 1: Introduction to PhysicsPhysics is a fundamental science that explores the laws governing the natural world. By studying physics, we can gain a deeper understanding of how the universe works. This unit serves as an introduction to the subject and provides a foundation for further exploration.Section 1: Basic Concepts1.1 Matter and EnergyIn this section, we learn about the concepts of matter and energy. Matter refers to anything that has mass and occupies space, while energy is the ability to do work. We explore the different forms of energy and their interconversion.1.2 Units and MeasurementsAccurate measurement is essential in physics. Here, we discuss the various units and measurement systems used in physics, such as SI units. We also learn about significant figures and how to perform calculations using them.Section 2: Mechanics2.1 Motion and ForcesThis section delves into the principles of motion and forces. We examine concepts such as displacement, velocity, and acceleration, as well as thevarious types and effects of forces. Newton's laws of motion are also introduced in this section.2.2 Energy and WorkUnderstanding the relationship between energy and work is crucial. We learn about different forms of energy, such as kinetic and potential energy, and how they are related to work. The principle of conservation of energy is also discussed.Section 3: Waves and Optics3.1 Wave PropertiesWaves are an integral part of physics. We explore the characteristics and properties of waves, including wavelength, frequency, and amplitude. This section covers different types of waves, such as sound waves and electromagnetic waves.3.2 OpticsOptics focuses on the behavior of light and its interaction with matter. Topics covered include reflection, refraction, and the formation of images by mirrors and lenses. We also learn about the basics of geometric optics.Unit 2: Electricity and MagnetismElectricity and magnetism are closely related phenomena that have a significant impact on our daily lives. This unit introduces the principles and applications of these concepts.Section 1: Electric Charge and Electric Field1.1 Electric ChargeHere, we learn about the fundamental property of matter known as electric charge. We explore the behavior of charged objects and the principles of electrostatics, including Coulomb's law.1.2 Electric FieldThe concept of an electric field is crucial for understanding how charges interact. We study the properties and behavior of electric fields, including how they are formed and their effects on charged particles.Section 2: Electric Circuits2.1 Current and ResistanceCurrent is the flow of electric charge, and resistance measures the opposition to this flow. We delve into the principles of current, resistance, and Ohm's law, which relates these quantities.2.2 Circuits and Circuit ElementsThis section focuses on electrical circuits and the various components that make them up. We learn about series and parallel circuits, as well as resistors, capacitors, and inductors.Section 3: Magnetism and Electromagnetism3.1 Magnetic FieldsMagnetic fields are responsible for the behavior of magnets and their interaction with other objects. We study the properties and behavior of magnetic fields, including their effects on moving charges.3.2 Electromagnetic InductionThe principle of electromagnetic induction is crucial for understanding the generation of electric currents. We explore Faraday's law and how changing magnetic fields can induce currents in conductors.Unit 3: Modern PhysicsModern physics revolutionized our understanding of the universe, particularly at the atomic and subatomic levels. This unit introduces the key concepts and discoveries of modern physics.Section 1: Quantum Mechanics1.1 Wave-Particle DualityThe wave-particle duality of matter and light is a cornerstone of quantum mechanics. We explore the behavior of particles and waves at the quantum level, including the famous double-slit experiment.1.2 Quantum States and Energy LevelsQuantum systems have discrete energy levels. Here, we learn about quantum states, wavefunctions, and the probabilistic nature of quantum mechanics. We also discuss the Schrödinger equation.Section 2: Particle Physics2.1 Subatomic ParticlesThis section focuses on the properties and classifications of subatomic particles, such as protons, neutrons, and electrons. We also introduce the concept of fundamental particles and their interactions.2.2 Nuclear ReactionsNuclear reactions involve changes in atomic nuclei and release tremendous amounts of energy. We study the principles behind nuclear reactions, including radioactive decay and nuclear fusion.ConclusionThe study of physics is essential for understanding the fundamental laws that govern our universe. This English textbook provides a comprehensive introduction to the subject, covering topics ranging from classical mechanics to modern physics. By studying this textbook and engaging with the content, students can develop a deep appreciation for the beauty and complexity of the natural world.。

nuclear energy 阅读理解阅读理解文章标题：Nuclear Energy（核能）Nuclear energy has been a controversial topic for decades. On one hand, it provides a source of clean, sustainable energy that can help mitigate the impact of greenhouse gas emissions on climate change. On the other hand, the use of nuclear energy is associated with safety concerns and the disposal of radioactive waste. In this article, we will explore the pros and cons of nuclear energy and its potential role in meeting the world's energy needs in the future.Pros of Nuclear Energy1. Zero Greenhouse Gas Emissions: Nuclear energy does not produce any greenhouse gas emissions during operation. It emits no carbon dioxide, methane, or other greenhouse gases, making it a clean alternative to fossil fuels like coal and oil. This helps reduce the overall carbon footprint of the energy sector and contributes to the fight against climate change.2. Sustainable Energy: Nuclear energy is a sustainable source of energy that can be used to power civilization for long periods of time. Unlike fossil fuels, which are finite resources, nuclear energy derives from the natural process of radioactive decay and can be used to generate electricity without depleting natural resources.3. Energy Security: Nuclear energy can provide a secure source of energy for countries that are dependent on imported fossil fuels. Developing countries with limited access to fossil fuels can use nuclear energy to meet their growing energy needs and achieve economic development.Cons of Nuclear Energy1. Safety Concerns: The operation of nuclear reactors requires extreme caution and rigorous safety measures to prevent accidents and mitigate the impact of any potential meltdown or radiation leak. Accidents like the Fukushima Daiichi nuclear disaster in Japan have raised concerns about the safety of nuclear energy and the potential impact on human health and the environment.2. Radioactive Waste: The production of nuclear energy generates radioactive waste that must be safely stored and disposed of for longperiods of time. The long-term storage and disposal of radioactive waste is a challenging problem that requires careful management and monitoring to prevent any potential environmental contamination or health risks.3. Cost and Infrastructure: The construction and operation of nuclear reactors require significant capital investment and infrastructure development. Nuclear energy is also more complex and expensive to operate compared to other renewable sources like solar and wind energy.The Future of Nuclear EnergyDespite its pros and cons, nuclear energy may have a role in meeting the world's future energy needs. Technologies are continuously improving to make nuclear reactors safer, more efficient, and less expensive to operate. Additionally, the development of advanced reactors using thorium or other alternative fuel sources could reduce the environmental impact and improve the sustainability of nuclear energy.In conclusion, nuclear energy is a complex topic that requires careful consideration of its pros and cons. While it has the potential to provide clean, sustainable, and secure energy, its use also carries safety risks and environmental challenges that must be addressed. As we strive to achieve global sustainability and reduce greenhouse gas emissions, it is important to continue researching and developing nuclear energy technologies while also investing in other renewable energy sources that can help meet our future energy needs.。

Day03知识点：观点点评与新旧观点辨析讲解经典例题Passage 109 （观点点评/ 难度-难/短篇文章）According to Hill and Spicer, the term “nation-state” is a misnomer, since the ideal model of a monolingual, culturally homogeneous state has never existed, not even among Europeans, who invented the nation-state concept and introduced it to the rest of the world. Modern European states, they argue, emerged after the Renaissance through the rise of nations (i.e., specific ethnic groups) to positions of political and economic dominance over a number of other ethnic groups within the bounded political territories. The term “nation-state”, Hill and Spicer argue, obscures the internal cultural and linguistic diversity of states that could more accurately be called “conquest states.” The resurgence of multiple ethnic groups within a single state, Hill says, is not “potentially threating to the sovereign jurisdiction of the state,” as Urban and Sherzer suggest; rather, the assertion of cultural differences threatens to reveal ethnocentric beliefs and practices upon which conquest states were historically founded and thus to open up the possibility for a “nations-state” in which conquered ethnic groups enjoy equal rights with the conquering ethnic group but do not face the threat of persecution or cultural assimilation into the dominant ethnic group.1. The primary purpose of the passage is toA. discuss issues relating to a form of political organization by raising doubts about the terminology used to refer to itB. trace changes in a form of political organization by examining the evolution of theC. justify the continued use of an established term for an evolving form of political organizationD. question the accuracy of a new term for a form of political organizationE. compare two terms for a form of political organizationDay03观点点评与新旧观点练习与讲解Passage 7 观点点评/文学评论/ 难Among many historians a belief persists that Cotton Mather’s biographies of some of the settlers of the Massachusetts Bay Colony (published 1702) are exercises in hagiography, endowing their subjects with saintly piety at the expense of historical accuracy. Yet modern studies have profited both from the breadth of information that Mather provides in, for example, his discussions of colonial medicineand from his critical observations of such leading figures as Governor John Winthrop. Mather’s wry humoras demonstrated by his detailed descriptions of events such as Winthrop’s efforts to prevent wood-stealingis overlooked by those charging Mather with presenting his subjects as extremely pious. The charge also obscures Mather’s concern with the settler’s material, not just spiritual, prosperity. Further, this pejorative view underrates the biographies value as chronicles: Mather amassed all sorts of published and unpublished documents as sources, and his selection of key events shows a marked sensitivity to the nature of the colony’s development.1. The primary purpose of the passage is toA. argue against a theory universally accepted by historical researchersB. call attention to an unusual approach to documenting a historical eraC. summarize research on a specific historical figureD. counter a particular view about the work of a biographerE. point out subtle differences among controversial historical reportsPassage 142 观点论证／自然科学地质／难Many theorists now doubt that heat loss from Earth’s core and radioactive decay are sufficient by themselves to produce all the energy driving the tectonic plates whose movements have helped shaped Earth’s surface. This leaves a loose end in current geological theory. Herbert Shaw argues that because scientists have underestimated the input of substantial amounts of energy from extraterrestrial impactors (asteroids and comets striking Earth), they have difficulty accounting for the difference between the quantity of energy produced from sources intrinsic to Earth and that involved in plate tectonics. Whereas most geologists have treated the addition of energy through the bombardment of Earth’s surface by such impactors as a process separate and independent from the movement of Earth’s tectonic plates, Shaw asserts that these processes are indivisible. Shaw’s revolutionary “open-system” view recognizes a continuum between terrestrial and extraterrestrial dynamics, whereas modern plate tectonic theory, like the classical geology developed during the nineteenth century, is founded on the view that Earth’s geological features have changed through gradual, regular processes intrinsic to Earth, without reference to unique catastrophic events. Classical geology borrowed a decisive, if unspoken, premise from Newton—the independence of Earth’s processes from any astronomical context.1. The author’s primary purpose is toA. identify the influences informing a particular geological theory about the processes that have shaped Earth’s surfaceB. identify differences between two views of the extraterrestrial impactors and argue that the phenomenon has influenced the development of plate tectonic theoryC. argue that an explanation is based on a dubious evidence and propose an alternative explanationD. discuss an explanation and place that explanation under theoretical contextE. suggest that apparent discrepancy poses a serious problem for a particular theory that many have believed。

高中精华双语文章：年轻的科学——地震预测5.12 大地震，日本3.11大地震......一次又一次的巨大灾难给人类带来了毁灭性地破坏，带走了多少人的生命。

为了减小破坏，挽救人们的生命，科学家们正在致力于地震预测的研究。

那么，地震真的可以预测吗？地震预测，虽是一门年轻的科学，科学家已经取得了一些成果。

相信未来地震发生时，我们已经做好了抵御灾难的充分准备。

The Young Science--Earthquake Prediction年轻的科学--地震预测Can earthquakes be predicted? Scientists are working on programs to predict where and when an earthquake will occur. They hope to develop an early warning system that can be used to forecast earthquakes so that lives can be saved.地震可以预报吗？科学家们正致力于研究预报何时何地会发生地震的计划，他们希望开发一种早期报警系统用来预报地震，以挽救人们的生命。

Earthquakes are the most dangerous and deadly or all natural events. They occur in many parts of the world. Giant earthquakes have been recorded in Iran, China, Guatemala, Chile, India, and Alaska. Two of the biggest earthquakes that were ever recorded took place in China and Alaska. These earthquakes measured about 8.5 on the Richter Scale. The Richter Scale was devised by Charles Richter in 1935, and compares the energy level of earthquakes. An earthquake that measures a 2 on the scale can be felt but causes little damage. One that measures 4.5 on the scale can cause slight damage, and an earthquake that has a reading of over 7 can cause major damage. It is important to note that a reading of 4 indicates an earthquake ten times as strong as one with a reading of 3. Scientists want to be able to predict those earthquakes that have a reading of over 4 on the Richter Scale.地震是自然灾害中最危险的最致命的，发生在世界许多地方。

新能源专业英语基础课文翻译新能源专业英语新能源专业英语新能源专业英语新能源专业英语１。

Pｕt ｔｈefolloｗiｎｇphrasｅｉntｏEnｇliｓh．Uｎiｔ11.温室效应thegreｅnhouseeｆfect2。

可再生能源ｒｅｎeｗaｂｌｅeｎeｒgy３．太阳能电池solar ｃell４。

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千瓦kiｌｏwaｔｔ6.沸水反应堆boiliｎgwaterreａcｔor7。

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Reading passage 3This is the third section of your IELTS Academic Reading test. You should spend about twenty minutes on it. Read the passage and answer questions 27-40.Helium’s future up in the airA) In recent years we have all been exposed to dire media reports concerning the impending demise of global coal and oil reserves, but the depletion of another key non-renewable resource continues without receiving much press at all. Helium – an inert, odourless, monatomic element known to lay people as the substance that makes balloons float and voices squeak when inhaled – could be gone from this planet within a generation.B) Helium itself is not rare; there is actually a plentiful supply of it in the cosmos. In fact,24 per cent of our galaxy’s elemental ma ss consists of helium, which makes it the second most abundant element in our universe. Because of its lightness, however, most helium vanished from our own planet many years ago. Consequently, only a miniscule proportion – 0.00052%, to be exact – remains in earth’s atmosphere. Helium is the by-product of millennia of radioactive decay from the elements thorium and uranium. The helium is mostly trapped in subterranean natural gas bunkers and commercially extracted through a method known as fractional distillation.C) The loss of helium on Earth would affect society greatly. Defying the perception of it as a novelty substance for parties and gimmicks, the element actually has many vital applications in society. Probably the most well known commercial usage is in airships and blimps (non-flammable helium replaced hydrogen as the lifting gas du jour after the Hindenburg catastrophe in 1932, during which an airship burst into flames and crashed to the ground killing some passengers and crew). But helium is also instrumental in deep-sea diving, where it is blended with nitrogen to mitigate the dangers of inhaling ordinary air under high pressure; as a cleaning agent for rocket engines; and, in its most prevalent use, as a coolant for superconducting magnets in hospital MRI (magnetic resonance imaging) scanners.D) The possibility of losing helium forever poses the threat of a real crisis because its unique qualities are extraordinarily difficult, if not impossible to duplicate (certainly, no biosynthetic ersatz product is close to approaching the point of feasibility for helium, even as similar developments continue apace for oil and coal). Helium is even cheerfully derided as a “loner” element since it does not adhere to other molecules like its cousin, hydrogen. According to Dr. Lee Sobotka, helium is the “most noble of gases, meaning it’s very stable and non-reactive for the most part … it has a closed electronic configuration, a very tightly bound atom. It is this coveting of its own electrons that prevents comb ination with other elements’. Another important attribute is helium’s unique boiling point, which is lower than that for any other element. The worsening global shortage could render millions of dollars of high-value, life-saving equipmenttotally useless. The dwindling supplies have already resulted in the postponement of research and development projects in physics laboratories and manufacturing plants around the world. There is an enormous supply and demand imbalance partly brought about by the expansion of high-tech manufacturing in Asia.E) The source of the problem is the Helium Privatisation Act (HPA), an American law passed in 1996 that requires the U.S. National Helium Reserve to liquidate its helium assets by 2015 regardless of the market price. Although intended to settle the original cost of the reserve by a U.S. Congress ignorant of its ramifications, the result of this fire sale is that global helium prices are so artificially deflated that few can be bothered recycling the substance or using it judiciously. Deflated values also mean that natural gas extractors see no reason to capture helium. Much is lost in the process of extraction. As Sobotka notes: "[t]he government had the good vision to store helium, and the question now is: Will the corporations have the vision to capture it when extracting natural gas, and consumers the wisdom to recycle? This takes long-term vision because present market forces are not sufficient to compel prudent practice”. For Nobel-prize laureate Robert Richardson, the U.S. government must be prevailed upon to repeal its privatisation policy as the country supplies over 80 per cent of global helium, mostly from the National Helium Reserve. For Richardson, a twenty- to fifty-fold increase in prices would provide incentives to recycle.F) A number of steps need to be taken in order to avert a costly predicament in the coming decades. Firstly, all existing supplies of helium ought to be conserved and released only by permit, with medical uses receiving precedence over other commercial or recreational demands. Secondly, conservation should be obligatory and enforced by a regulatory agency. At the moment some users, such as hospitals, tend to recycle diligently while others, such as NASA, squander massive amounts of helium. Lastly, research into alternatives to helium must begin in earnest.Questions 27–31Reading passage 3 has six paragraphs, A–F.Which paragraph contains the following information?Questions 32–35Do the following statements agree with the claims of the writer in Reading passage 3? Answer Yes, No or Not given to questions 32-35.Questions 36–40Complete the summary below.Choose no more than two words from the passage for each answer.。

Radioactive decay lines from asymmetric supernova explosionsA.HungerfordLos Alamos National Laboratory,P.O.Box 1663,Los Alamos,NM 87545,USASteward Observatory,University of Arizona,USAAbstractHigh energy emission from supernovae provide a direct window into the quantity and distribution of radioactive elements produced in these bining supernova explosion calculations with 3D Monte Carlo c -ray transport,I have studied the effect mixing and asymmetries have on the hard X-ray and c -ray spectra.With sufficient spectral resolution,the emission line profiles from nickel decay have enough information to distinguish between spherical and mildly asymmetric supernova explosions.Ó2003Elsevier B.V.All rights reserved.PACS:95.85.Pw;97.60.BwKeywords:c -rays ;Supernovae;Asymmetries1.IntroductionThe past decade has brought great strides in observational and theoretical studies of core-col-lapse supernovae,with interest stimulated by the wealth of data (and surprises)obtained from SN 1987A.For theoretical work in particular,the early emergence of hard X-and c -ray emission from SN 1987A (X-rays:e.g.Dotani et al.,1987;c -rays:e.g.Cook et al.,1988;Mahoney et al.,1988;Matz et al.,1988)signaled a departure from the spherically symmetric geometry that had been as-sumed in models of core-collapse explosions to that point.The appearance of this high energy emission,nearly 6months earlier than theorists had predicted,was most readily explained by theoutward mixing of the nickel synthesized in the inner layers of the explosion (e.g.Pinto and Woosley,1988a;Arnett et al.,1989a,b and refer-ences therein).In addition,line profiles from iron (the daughter product of nickel decay)were broadened to roughly 3500km/s (Spyromilio et al.,1990),further evidence that nickel had been mixed to large radii in the homologous supernova ejecta.This qualitative explanation for the observations motivated several groups to investigate,at a de-tailed level,the multidimensional instabilities which give rise to such mixing within the context of massive star explosions (Arnett et al.,1989a,b;Hachisu et al.,1990;Herant and Benz,1992;Kifonidis et al.,2000).The hydrodynamical sim-ulations carried out by these groups resulted in extended spatial distributions of the nickel,but not sufficiently extended to match the line profiles of the iron emission from SN 1987A.E-mail address:**************(A.Hungerford).1387-6473/$-see front matter Ó2003Elsevier B.V.All rights reserved.doi:10.1016/j.newar.2003.11.001New Astronomy Reviews 48(2004)19–24/locate/newastrevA number of ways to enhance the mixing in theoretical calculations,thus bringing them into agreement with observations,were proposed by Herant and Benz(1992):(1)the decay of56Ni could inject enough energy to force additional mixing,(2)convection in the pre-collapse core could seed more vigorous mixing and(3)global asymmetries in the explosion mechanism itself could enhance mixing along a particular direction in the explosion.This third possibility has been invoked to explain several other observational puzzles regarding core-collapse events.Nagataki et al.(1998)found that not only could slight asymmetries in the supernova explosion produce the required mixing to explain1987A,but they could also explain anomalies in the nucleosyn-thetic yields produced by several supernovae. Furthermore,the most straightforward explana-tion of the large polarization seen in core-collapse supernovae(see Leonard and Filippenko,2001 and references therein)is that the explosion driv-ing these supernovae is inherently asymmetric (H€oflich,1991).In addition,the high observed velocities of pulsars and the formation scenarios of neutron star binaries both suggest that neutron stars are given strong kicks at birth.These kicks are most easily explained by some asymmetry in the supernova explosion where the neutron star is born(see Fryer et al.,1996for a review).In this proceeding,we present theoretical c-ray spectra calculated using asymmetric supernova models as input to a Monte Carlo c-ray transport code.The asymmetry of the input model is moti-vated by the strong asymmetries that stellar rota-tion has been shown to produce in the supernova explosion(M€o nchmeyer and M€u ller,1989;Janka and M€o nchmeyer,1989;Fryer and Heger,2000; Khokhlov et al.,1999).The nature of these asymmetries depends upon the angular momen-tum profile of the collapsing star and,although most calculations predict jet-like explosions along the rotation axis,some calculations imply that an equatorial explosion could occur(M€o nchmeyer and M€u ller,1989).Our spectral calculations were carried out for both a jet-like explosion with axis ratio of2:1(motivated by Fryer and Heger(2000); we refer to this explosion model as Jet2)and a symmetric explosion model(Symmetric).Our analysis of these model spectra concentrates on the differences in total luminosity and line profile shape with the introduction of realistic explosion asymmetries.Since the progenitor star used as in-put to our simulations was a15M red supergiant, we are unable to directly compare our calculated spectra with the observed high energy spectra of SN1987A.However,we discuss how our models compare to various spectral trends observed from SN1987A.2.c-ray line profilesThe high energy spectra were calculated using a Monte Carlo technique,similar to that described in Ambwani and Sutherland(1988),for modeling c-ray transport in three-dimensions.Input models of the supernova ejecta(element abundances, density and velocities)were taken from3D SPH explosion simulations(Hungerford et al.,2003; models Jet2and Symmetric)and mapped onto a 140Â140Â140Cartesian grid.Escaping photons were tallied into250coarse energy bins,withfiner binning at the decay line energies to provide line profile information.The emergent photons were also tallied into11angular bins(D h¼10°)along the polar axis(the models investigated in this work are essentially axisymmetric,alleviating the need to tally in azimuthal angle as well.)A detailed look at the c-ray line profile shapes and strengths,for the1.238and0.847MeV56Co lines,reveals clear trends with viewing angle.Fig.1 shows line profiles of the0.847MeV56Co line for both the Symmetric and Jet2explosion models. We have placed this object at the distance of the Large Magellanic Cloud(60kpc)for easy com-parison withflux data from SN1987A observa-tions.The broadening of the line is caused by Doppler velocity shifts resulting from the spatial distribution of radioactive nickel in the homolo-gously expanding ejecta.The four panels are shown for days200,250,300and365after ex-plosion.The three lines in the Jet2spectra repre-sent different viewing angles through the ejecta (along the pole,the equator and an intermediate angle$45°.)For the Symmetric spectra,we have plotted these same viewing angles.20 A.Hungerford/New Astronomy Reviews48(2004)19–24As we can see from the abovefigure,both ex-plosion scenarios(Symmetric and Jet2)show blue-shifted line profiles,though to varying degree. These differences can be best understood by examining the physical effects which dictate the formation of the line profile edges.The blue edge to the lines is set by the maximum observed line of sight velocity of the56Co in the ejecta.Since the expansion is basically homologous after100days, the line of sight velocity of afluid element in the ejecta is proportional to its distance above the mid-plane of the explosion.Each spectral energy bin in the line profile can be mapped to a unique line of sight velocity in the ejecta,which can in turn be mapped to a specific height above the mid-plane.For example,defining the line of sight to be along the z-axis,the line profile shape should be proportional to the total mass of cobalt summed in x and y as a function of z height in the ejecta. Therefore,the bluest edge of the line will arise from material that was mixed furthest out along the line of sight direction.Fig.2shows a contour plot of density(outer contour)and56Co number density(inner contour) for the Jet2and Symmetric models at t¼150days. Decay of56Co is the major source of c-ray pho-tons,so the inner contour essentially traces the surface of the emission region.The horizontal and vertical lines in Fig.2represent lines of sight from the ejecta surface to the emission source and are labeled with the optical depth along that line-of-sight.The dominant opacity for the hard X-and c-rays is Compton scattering offelectrons and,since the density contours remainroughly A.Hungerford/New Astronomy Reviews48(2004)19–2421spherical in both models,the optical depth from a given point to the ejecta surface is roughly constant.It is clear from Fig.2that the nickel was mixed further out in the polar direction (z -axis of Fig.2)of the asymmetric explosion.Following the arguments above,it is not surprising that the c -ray line profiles viewed along the polar direction are much more blue-shifted for the Jet2model than the Symmetric model.Fig.2does not show a very large difference in the extent of mixing along the equatorial direc-tion between the two models.Correspondingly,the blue edge of the Symmetric lines and the equator view of the Jet2lines are comparable.The red edge of the lines is determined by the escaping emission from 56Co with the smallest line of sight velocity in the ejecta.In a Symmetric model,this should be an indication of how deep into the ejecta we can see along a given viewing angle.However,there is a more pronounced effect at play in the asymmetric explosion models.Much of the c -ray emission for the equatorial view arises from the ‘‘tips’’of the elongated 56Co distribution.This material has a very low line of sight velocity for an equatorial observer,since it is being ejected predominantly in the polar direction.This allows for a significantly lower velocity red edge of the equator view lines,even though the optical depth profiles do not vary much between polar and equator viewing angles.It is interesting to note that the c -ray line pro-files from SN 1987A were in fact red-shifted,a trend that is not obtained with these simulations.Although the c -ray data uncertainties were quite high,this red-shift was also observed in the far infrared forbidden lines of FeII,providing verifi-cation for the c -ray line centroid measurements.As was discussed above,the spectral line shape is directly correlated with the total cobalt mass at a given z -coordinate along the line-of-sight.With this in mind,the observed red-shifted line profiles towards SN 1987A imply,not only a break in spherical symmetry,but also a break in axisym-metry of the ly,there should be more nickel/cobalt mass on the far side of SN 1987A Õs ejecta as seen from our viewing angle.Pulsar ve-locity distributions also support the need for some non-axisymmetry in core-collapse supernova ex-plosions.An interesting study,which will be ad-dressed in a future paper,is to link the magnitude of velocity kick imparted to a neutron star with the compositional asymmetry implied by the red-shif-ted line profiles of SN 1987A.3.Hard X-ray and c -ray spectrumFig.3is a logarithmic plot of the calculated photon flux (c /s/MeV/cm 2)across the entireenergyFig.2.Contour plots in the xz -plane of the Symmetric and Jet2explosion models at t ¼150days.Inner contour is for 56Co number density which traces the surface of the c -ray emitting region.Outer contour is for the mass density which follows electron density and thus traces the dominant opacity source (Compton scattering).The lines represent lines-of-sight through the ejecta for which the optical depth from emission region to ejecta surface has been calculated.Regardless of viewing angle,the optical depth of the 56Co ejected along the poles in the Jet2explosion remains quite low.Hence,it is this material that dominates the observed emission for all viewing angles in the aspherical explosion.22 A.Hungerford /New Astronomy Reviews 48(2004)19–24range investigated with these simulations(0.3keV to4MeV).Thefive panels are spectra from the different time slices;in each panel,we plot the spectrum for the Symmetric model,along with polar and equatorial views of the Jet2model.The effects of mixing are present in both these simula-tions,though at differing levels due to the differ-ences in explosion asymmetry.It can be seen immediately that the hard X-rays emerge earlier from the ejecta with a global explosion asymmetry (Jet2model).This holds regardless of viewing an-gle(pole versus equator)towards the explosion.As discussed in Section1,the observed high energy spectrum of SN1987A differed from the predictions of theoretical onion-skin models in two fundamental ways.Both the broad lines of nickel and the early emergence of the hard X-rays could be explained qualitatively by invoking a mixing argument.From a theoretical standpoint,including a1D prescription for that mixing makes the as-sumption that both data points can befit with one free parameter.However,the simulations in this work suggest that the addition of a global asym-metry will change the direct correlation between the emergence time and the degree of line broadening. That is to say,for a given hard X-rayflux,the Symmetric model will correspond to a single line profile,regardless of viewing angle.The Jet2model, however,produces similar hard X-ray continua for different viewing angles,but the line profile varies significantly with viewing angle.In fact,the data for SN1987A(the c-line profiles and hard X-ray continuum)were notfit well by1D models.In particular,the model10HMM(Pinto and Woos-ley,1988a),which was mixed sufficiently to account for theflux in the hard X-ray continuum observa-tions,resulted in c-line centroids that were shifted too far to the blue(Tueller et al.,1990).Although the uncertainties in these data were relatively large, this trend may be in the right direction to suggest a global asymmetry(i.e.,an asymmetric explosion scenario for SN1987A could produce thesame A.Hungerford/New Astronomy Reviews48(2004)19–2423hard X-rayflux level,but with a redder line profile than the symmetric explosion scenario). 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decay的固定搭配和用法一、基本用法“decay”主要用作动词和名词。

1. 作动词时，基本含义为“（使）腐烂；（使）腐朽；衰退；（力量、影响等）减弱”等。

例如：- The old wooden bridge is starting to decay.（这座古老的木桥开始腐烂了。

）- Sugar can decay your teeth if you eat too much of it.（如果你吃太多糖，糖会蛀坏你的牙齿。

）2. 作名词时，意为“腐烂；腐朽；衰退；衰减”等。

例如：- The decay of the ancient building was a sad sight.（那座古建筑的腐朽是一种令人悲伤的景象。

）- There has been a decay in his mental abilities over the years.（多年来他的心智能力有所衰退。

）二、固定搭配1. “tooth decay”（蛀牙，龋齿）- My dentist told me that I have serious tooth decay.（我的牙医告诉我我有严重的蛀牙。

）- Tooth decay can be prevented by regular brushing.（通过经常刷牙可以预防蛀牙。

）2. “radioactive decay”（放射性衰变）- Scientists are studying the process of radioactive decay.（科学家们正在研究放射性衰变的过程。

）- Radioactive decay is a natural phenomenon.（放射性衰变是一种自然现象。

）3. “moral decay”（道德败坏）- The increase in crime is a sign of moral decay in society.（犯罪的增加是社会道德败坏的一个标志。

核污染的影响英语作文The Impact of Nuclear Pollution.The mention of nuclear pollution conjures images of catastrophic events and long-lasting environmental degradation. Nuclear pollution, often caused by the leakage of radioactive materials from nuclear reactors or weapons testing, has the potential to cause widespread and long-term harm to both human health and the natural world. The impact of nuclear pollution is profound and multifaceted, affecting everything from the smallest microorganisms to the largest ecosystems.At the fundamental level, radioactive materials affect the structure and function of matter. Radioactive decay, a spontaneous process by which unstable atoms emit radiation and transform into more stable atoms, is the root cause of this pollution. The released radiation, which includes alpha, beta, and gamma particles as well as neutrons and x-rays, is highly energetic and can ionize atoms, alteringtheir chemical properties and potentially causing damage to cellular structures.For humans, exposure to radiation can result in a range of acute and chronic health effects. Acute exposure can lead to radiation sickness, which may manifest as nausea, vomiting, hair loss, and skin rashes. In severe cases, it can even be fatal. Long-term exposure, even at low levels, can increase the risk of cancer, genetic mutations, and other chronic health conditions. The impact is particularly severe for children and pregnant women, as their bodies are more sensitive to the harmful effects of radiation.The environmental impact of nuclear pollution is equally devastating. Radioactive materials can contaminate soil and water bodies, affecting the ecological balance. Radioactive contamination of soil can disrupt the soil microbiome, reducing biodiversity and affecting plant growth. This, in turn, can disrupt food chains and affect the entire ecosystem. Radioactive contamination of water bodies can lead to the accumulation of radioactive materials in aquatic organisms, posing a threat to bothhuman and animal consumers of these organisms.The cleanup of nuclear pollution is a complex andcostly task. The radioactive half-life of many materials is measured in decades or even centuries, meaning that the cleanup efforts may span generations. The use of specialized equipment and personnel trained in radiation safety is essential to ensure that cleanup operations are carried out safely and effectively.The prevention of nuclear pollution is crucial, as itis both costly and difficult to mitigate its effects.Strict regulations and safety measures must be implemented to ensure the safe operation of nuclear reactors and the secure storage of radioactive materials. Additionally, the development of safer and more sustainable energy sources can help reduce the need for nuclear power, further reducing the risk of nuclear pollution.In conclusion, the impact of nuclear pollution is profound and far-reaching. It poses a threat to human health, ecological balance, and the economic well-being ofcommunities. The prevention and mitigation of nuclear pollution must be a priority for governments, industries, and individuals alike. By investing in safer energy sources, implementing strict regulations, and ensuring the secure storage and disposal of radioactive materials, we can help protect ourselves and our planet from the devastatingeffects of nuclear pollution.。

探索原子结构与基本粒子：深入了解原子物理的重要知识点Exploring Atomic Structure and Elementary Particles: A Deep Dive into Key Concepts of Atomic PhysicsAtomic physics is a branch of physics that delves into the structure and behavior of atoms and their constituent particles. It seeks to unravel the mysteries of the fundamental building blocks of matter and understand the interactions that govern the behavior of the universe at the smallest scales. In this article, we will explore some of the crucial concepts in atomic physics, including the structure of atoms, the properties of elementary particles, and the forces that bind them together.探索原子结构与基本粒子：深入了解原子物理的重要知识点原子物理是物理学的一个分支，深入研究原子及其组成粒子的结构和行为。

它试图解开物质的基本构建单元的奥秘，并理解统治宇宙在最小尺度上行为的相互作用。

在本文中，我们将探索原子物理中一些关键的概念，包括原子的结构、基本粒子的性质以及将它们结合在一起的力。

The Structure of Atoms原子的结构At the heart of atomic physics lies the structure of atoms. Atoms consist of a nucleus, which is composed of protons and neutrons, surrounded by a cloud of electrons orbiting around the nucleus. The nucleus carries a positive electric charge due to the presence of protons, while electrons carry a negative charge. The number of protons determines the atomic number of an element, while the number of neutrons can vary, leading to different isotopes of the same element.原子物理的核心是原子的结构。

Thulium Isotopes Radioactive Decay Studies Thulium is a rare earth element that has a total of 32 isotopes, with only one of them being stable, Thulium-169. The rest of the isotopes are radioactive, and they undergo different types of decay. Thulium isotopes have been the subject of many studies, as they have potential applications in nuclear medicine, nuclear energy, and environmental monitoring. In this essay, we will discuss the radioactive decay of thulium isotopes and their applications.Thulium isotopes decay through different processes, including alpha decay, beta decay, and electron capture. Alpha decay is the most common type of decay for thulium isotopes, and it occurs when the nucleus emits an alpha particle, which is a helium nucleus consisting of two protons and two neutrons. Thulium-171, for example, decays through alpha decay to produce Ytterbium-167. Beta decay, on the other hand, occurs when a neutron in the nucleus is converted into a proton, and an electron and an antineutrino are emitted. Thulium-170, for instance, decays through beta decay to produce Ytterbium-170. Electron capture occurs when an electron is captured by the nucleus, and a proton is converted into a neutron, emitting a neutrino. Thulium-168, for instance, decays through electron capture to produce Erbium-168.The radioactive decay of thulium isotopes has several applications in different fields. One of the most important applications is in nuclear medicine, where thulium-170 is used for cancer treatment. Thulium-170 emits beta particles that can penetrate cancer cells and destroy them. The beta particles have a short range, which means that they can target cancer cells without damaging healthy cells. Thulium-170 also has a short half-life of only 128 days, which means that it can be easily eliminated from the body after treatment.Another important application of thulium isotopes is in nuclear energy. Thulium-170 can be used as a fuel in nuclear reactors, where it undergoes fission to produce energy. Thulium-170 has several advantages over other nuclear fuels, including its high energy density, low neutron absorption cross-section, and low radioactivity. Thulium-170 also has a short half-life, which means that it produces less nuclear waste than other nuclear fuels.Thulium isotopes can also be used in environmental monitoring. Thulium-170 can be used as a tracer to study the movement of water in soil and rocks. Thulium-170 emits gamma rays that can be detected using a gamma-ray spectrometer. By measuring the gamma-ray emissions, scientists can determine the concentration of thulium-170 in the soil or rock, and hence, the movement of water.In conclusion, thulium isotopes are important radioactive elements that undergo different types of decay, including alpha decay, beta decay, and electron capture. Thulium isotopes have several applications in different fields, including nuclear medicine, nuclear energy, and environmental monitoring. Thulium-170, in particular, is an important isotope that can be used for cancer treatment and as a fuel in nuclear reactors. Thulium isotopes are also useful as tracers in environmental studies. Further research on thulium isotopes is needed to explore their potential applications and to understand their behavior in different environments.。