Superwords-equation&symbol
参考文献的标准格式1
参考文献著录格式标准规范参考文献应引作者亲自阅过的近年的主要文献,一般文章不超过5篇,评述、综述性文章不超过20篇。
未公开发表的资料请勿引用,但可作脚注处理。
参考文献列于文后,正文中也须用上角标标出引用文献的序号。
参考文献用“顺序编码制”,即各篇文献按其在正文中的标注序号依次列出。
参考文献条目著录:个人著者采用姓在前,名在后的著录格式。
作者3人以下全部著录,4人以上只著录前3人,之间加“,”,后加“等” 或“etal”。
1.参考文献类型及标识2.文后参考文献编排格式(1)专著、论文集、学位论文、报告[序号]作者.文献题名[文献类型标识] .出版地:出版者.出版年,起止页码(任选).范例:[1]杨浩滨.食品微生物学[M].北京:北京农业大学出版社,1995,28-30.(2) 期刊文章[序号]主要责任者.文献题名[J].刊名,年,卷(期):起止页码.范例:[5]肖凯军.大豆分离蛋白的酶法改性[J]. 食品科学,1995,16(9):30-34.范例:[7]OUJP,YOSHIDA O,SOONGT, etal. Recent advance in research on applications energy dissipation systems[J]. Earthquake Eng , 1997,38(3): 358-361.(3) 论文集[序号]作者.文献题名[A].编者.论文题名[C].出版地:出版者,出版年,起止页码.范例:[8]瞿秋白.现代文明的问题与社会主义[A] .罗荣渠.从西化到现代化[C].北京:北京大学出版社,1990,121-133.(4) 报纸文章[序号]作者.文献题名[N].报纸名,出版日期(版次).范例:[10] 胡鞍钢. 中国能够实现粮食自给目标[N].联合早报,1994,10.(5) 国际、国家标准[序号]标准编号,标准名称[S].范例:[11]GB/T 16159-1996 ,汉语拼音正词法基本规则[S]. (6) 专利[序号]专利所有者.专利题名[P].专利国别:专利号,出版日期.范例:[12]姜锡洲. 一种温热外敷药制备方案[P].中国专利:881056073,1989,07,26.(7) 电子文献[序号]作者.电子文献题名[电子文献及载体类型标名].电子文献的出处或可获得地址,发表或更新日期/引用日期(任选).范例:[13]王明亮.关于中国学术期刊标准化数据库系统工程的进展[EB OL]. , 1998,08,16/1998,10,04.(8)各种未定义类型的文献[序号]主要责任者.文献题名.出版地:出版者,出版年.范例:[15]张永禄. 唐代长安词典[Z].西安:陕西人民出版社,1980. 毕业论文参考文献规范格式专著-M;论文集-C;报刊-N;期刊文章-J;学位论文-D;报告-R;专著或论文集中析出的文献-A;标准-S;专利- P;对于不属于上述的文献类型,采用字母“Z”标识。
朗道十卷英文名
朗道十卷英文名朗道十卷是世界著名物理学教材。
朗道十卷英文名如下所示。
一、《朗道理论物理学教程第一卷:力学》Course of Theoretical Physics Volume one: Mechanics二、《朗道理论物理学教程第二卷:场论》Course of Theoretical Physics Volume two: The Theory of Fields三、《朗道理论物理学教程第三卷:量子力学(非相对论理论) 》Course of Theoretical Physics Volume three: Quantum Mechanics (Non-relativistic Theory)四、《朗道理论物理学教程第四卷:量子电动力学》Course of Theoretical Physics Volume four: Quantum Electrodynamics 五、《朗道理论物理学教程第五卷:统计物理学》Course of Theoretical Physics Volume five: Statistical Physics六、《朗道理论物理学教程第六卷:流体动力学》Course of Theoretical Physics Volume six: Fluid Mechanics七、《朗道理论物理学教程第七卷:弹性理论》Course of Theoretical Physics Volume seven: Theory of Elasticity八、《朗道理论物理学教程第八卷:连续介质电动力学》Course of Theoretical Physics Volume eight: Electrodynamics of Continuous Media九、《朗道理论物理学教程第九卷:统计物理学》Course of Theoretical Physics Volume nine: Statistical Physics十、《朗道理论物理学教程第十卷:物理动理学》Course of Theoretical Physics Volume ten: Physical Kinetics。
scholarone manuscripts公式
在撰写高质量、深度和广度兼具的文章之前,我们需要对指定的主题进行全面评估。
在本篇文章中,我们将深入探讨scholarone manuscripts公式,从简到繁地探讨该主题,以便读者能更深入地理解。
文章内容将包含评估、个人观点和理解,以及总结回顾性的内容,以帮助读者全面、深刻和灵活地理解这一主题。
让我们对scholarone manuscripts公式进行全面评估。
scholarone manuscripts是一款学术论文管理系统,旨在帮助学术期刊和出版商更高效地处理投稿、审稿和出版流程。
而在这个系统中,公式的使用频繁且至关重要。
公式在学术论文中扮演着关键的角色,能够准确地描述科学、技术和工程领域的理论和实验结果,如何在scholarone manuscripts中编写和编辑公式是非常重要的。
在scholarone manuscripts中,公式的插入和编辑通常需要遵循特定的格式和规范。
作者需清晰地列出每个公式的编号,并在文中多次提及公式文字,以便读者能够更容易地理解和引用。
公式的排版需要符合学术出版的标准,包括准确的数学符号、正确的排列和清晰的显示效果。
作者需要熟悉scholarone manuscripts的公式编辑功能,以便高效地完成公式的编写和编辑工作。
在撰写具有深度和广度的文章时,我们应该从使用scholarone manuscripts公式的基本操作开始,介绍如何插入和编辑公式。
进而,我们还需要探讨公式的高级排版和显示效果,包括如何调整公式的大小、引用外部公式库以及处理特殊格式的公式。
通过逐步介绍这些内容,读者可以更深入地了解如何在scholarone manuscripts中精确、规范地撰写学术公式。
另外,在文章中,我们还需要共享对这一主题的个人观点和理解。
在我看来,scholarone manuscripts公式的使用不仅是一种技术操作,更是一种学术态度和修养的体现。
准确、清晰地呈现学术公式可以提高论文的可读性和可引用性,有助于读者更好地理解研究成果并推动学术交流。
[MATLAB图书合集].Numerical.Simulation.of.Optical.Wave.
Numerical Simulation of Optical Wave PropagationWith examples in MATLAB®Library of Congress Cataloging-in-Publication DataSchmidt, Jason Daniel, 1975-Numerical simulation of optical wave propagation with examples in MATLAB / Jason D. Schmidt.p. cm. -- (Press monograph ; 199)Includes bibliographical references and index.ISBN 978-0-8194-8326-31. Optics--Mathematics.2. Wave-motion, Theory of--Mathematical models.3. MATLAB. I. Title.QC383.S36 2010535'.42015118--dc222010015089Published bySPIEP.O. Box 10Bellingham, Washington 98227-0010 USAPhone: +1 360.676.3290Fax: +1 360.647.1445Email: Books@Web: Copyright © 2010 Society of Photo-Optical Instrumentation Engineers (SPIE)All rights reserved. No part of this publication may be reproduced or distributed in any form or by any means without written permission of the publisher.The content of this book reflects the work and thoughts of the author(s).Every effort has been made to publish reliable and accurate information herein, but the publisher is not responsible for the validity of the information or for any outcomes resulting from reliance thereon.Printed in the United States of America.About the cover: 50-watt laser for generating mesospheric sodium guide stars over 90 km above the ground. In operation at the Air Force Research Laboratory's 3.5-m telescope at the Starfire Optical Range, Kirtland AFB, NM. (Robert Q. Fugate, © 2005, Albuquerque, NM).Numerical Simulation of Optical Wave PropagationWith examples in MATLAB®Jason D. SchmidtBellingham, Washington USAContentsPreface (ix)Chapter 1 Foundations of Scalar Diffraction Theory (1)1.1 Basics of Classical Electrodynamics (1)1.1.1 Sources of electric and magnetic fields (2)1.1.2 Electric and magnetic fields (2)1.2 Simple Traveling-Wave Solutions to Maxwell's Equations (5)1.2.1 Obtaining a wave equation (5)1.2.2 Simple traveling-wave fields (7)1.3 Scalar Diffraction Theory (9)12............................................................................................Problems1.4Chapter 2 Digital Fourier Transforms (15)2.1 Basics of Digital Fourier Transforms (15)2.1.1 Fourier transforms: from analytic to numerical (15)2.1.2 Inverse Fourier transforms: from analytic to numerical (17)2.1.3 Performing discrete Fourier transforms in software (18)2.2 Sampling Pure-Frequency Functions (21)2.3 Discrete vs Continuous Fourier Transforms (23)2.4 Alleviating Effects of Discretization (26)2.5 Three Case Studies in Transforming Signals (30)Sincsignals (30)2.5.12.5.2 Gaussian signals (31)2.5.3 Gaussian signals with quadratic phase (33)2.6 Two-Dimensional Discrete Fourier Transforms (35)37............................................................................................Problems2.7Chapter 3 Simple Computations Using Fourier Transforms (39)39......................................................................................Convolution3.143........................................................................................3.2Correlation3.347Functions............................................................................Structure50........................................................................................Derivatives3.43.5 Problems (53)Chapter 4 Fraunhofer Diffraction and Lenses (55)4.1 Fraunhofer Diffraction (55)4.2 Fourier-Transforming Properties of Lenses (58)4.2.1 Object against the lens (59)4.2.2 Object before the lens (59)4.2.3 Object behind the lens (61)4.3 Problems (64)Chapter 5 Imaging Systems and Aberrations (65)65........................................................................................5.1Aberrations5.1.1 Seidel aberrations (66)5.1.2 Zernike circle polynomials (66)5.1.2.1 Decomposition and mode removal (73)5.1.2.2 RMS wavefront aberration (75)5.2 Impulse Response and Transfer Function of Imaging Systems (77)5.2.1 Coherent imaging (77)5.2.2 Incoherent imaging (79)5.2.3 Strehl ratio (82)............................................................................................84Problems5.3Chapter 6 Fresnel Diffraction in Vacuum (87)6.1 Different Forms of the Fresnel Diffraction Integral (88)6.2 Operator Notation (89)6.3 Fresnel-Integral Computation (90)6.3.1 One-step propagation (90)6.3.2 Two-step propagation (92)6.4 Angular-Spectrum Propagation (95)6.5 Simple Optical Systems (102)6.6 Point Sources (107)..........................................................................................113 Problems6.7Chapter 7 Sampling Requirements for Fresnel Diffraction (115)7.1 Imposing a Band Limit (115)7.2 Propagation Geometry (117)7.3 Validity of Propagation Methods (120)7.3.1 Fresnel-integral propagation (120)7.3.1.1 One step, fixed observation-plane grid spacing (120)7.3.1.2 Avoiding aliasing (121)7.3.2 Angular-spectrum propagation (124)7.3.3 General guidelines (128)7.4 Problems (130)Chapter 8 Relaxed Sampling Constraints with PartialPropagations (133)8.1 Absorbing Boundaries (134)8.2 Two Partial Propagations (135)8.3 Arbitrary Number of Partial Propagations (138)8.4 Sampling for Multiple Partial Propagations (139)8.5 Problems (146)Chapter 9 Propagation through Atmospheric Turbulence (149)9.1 Split-Step Beam Propagation Method (149)9.2 Refractive Properties of Atmospheric Turbulence (150)9.2.1 Kolmogorov Theory of turbulence (152)9.2.2 Optical propagation through turbulence (156)9.2.3 Optical parameters of the atmosphere (157)9.2.4 Layered atmosphere model (164)9.2.5 Theory (164)9.3 Monte-Carlo Phase Screens (166)9.4 Sampling Constraints (172)9.5 Executing Properly Sampled Simulation (174)9.5.1 Determine propagation geometry and turbulenceconditions (174)9.5.2 Analyze the sampling constraints (176)9.5.3 Perform a vacuum simulation (178)9.5.4 Perform the turbulent simulations (179)9.5.5 Verify the output (180)9.6 Conclusion (182)9.7 Problems (183)Appendix A Function Definitions (185)Appendix B MATLAB Code Listings (187)References (189)Index (195)PrefaceDiffraction is a very interesting and active area of optical research.Unfortunately, analytic solutions are rare in many practical problems,particularly when optical waves propagate through randomlyfluctuating media.For many of these problems, researchers must resort to numerical solutions.Still,simulations in optical diffrac-tion are ually,these simulations take advantage of discrete Fourier transforms,which means using discretely spaced samples on afinite-sized grid. This leads to a few tradeoffs in speed and memory versus accuracy.Thus,the pa-rameters of the sampling grids must be chosen very carefully.Some people seek to fully automate those choices,but this cannot be done automatically in every case. To determine grid properties,one must carefully consider computational speed, available computer memory,the Nyquist sampling criterion,geometry,accurate representation of source apertures,and impact on the propagatedfield’s quantities of interest.This book grew out of an independent study I did while I was a doctoral student at University of Dayton.The study was directed by LtCol Matthew Goda,then a professor at the Air Force Institute of Technology(AFIT).After the independent study was over,Goda then created a course at AFIT on wave-optics simulations. When I graduated,I became a professor at AFIT while Goda moved on to a new military assignment.When I began teaching the wave-optics simulation course, there was no book written to the level of detail required for a graduate course fo-cused on wave-optics simulations and sampling requirements.The course was al-ways taught out of the professor’s notes,originally compiled by piling these notes was no small feat,and Goda did a tremendous job combining material from books on discrete Fourier transforms,optics journal articles and conference proceedings,technical reports from companies like the Optical Sciences Company and MZA Associates Corporation,and private communication with researchers.Until this book,simulations have always been an afterthought in just a few books on image processing and nonlinear optics.Clearly there was a gap between the practical knowledge required to perform wave-optics simulations and the the-oretical material covered in great Fourier-optics textbooks like those by Joseph Goodman and Jack Gaskill.I have heard professors across the U.S.talk about how they include material on simulations in their graduate Fourier-optics courses.I ap-plaud them for that effort because it is challenging to teach students both the the-ory and practical simulation of Fourier optics in one course.However,if the stu-ixdents are to become capable enough to write wave-optics simulations for thesis or dissertation research and beyond,they cannot get enough detail in a one-term Fourier-optics course.This is why AFIT has separate courses on Fourier optics and wave-optics simulations.This book is intended for graduate students in programs like physics,electrical engineering,electro-optics,or optical science.The book gives all of the relevant equations from Fourier optics,but to fully understand and appreciate the material, it is important to have a thorough understanding of Fourier optics before reading this book.I believe that part of the benefit of this book is the use of specific code examples, rather than just pseudo-code.However,the programming or scripting language for the examples needs to be one that is widely used and easy to understand by those who do not already use it.For those reasons,I have used M ATLAB in all of the examples throughout this book.It is heavily used in engineering both at universities and research institutions.Further,it is easy to read because of its simple language and because many numerical algorithms,such as discrete Fourier transforms and convolution,are part of its basic library.If I used other languages like C,C++, FORTRAN,Java,and Python,I would need to pick a particular external library of numerical routines or write my own algorithms and include them in the book.I believe that using M ATLAB in this book allows readers to focus on the wave propagation,rather than the most basic numerical algorithms like discrete Fourier transforms.Further,any user with access to the M ATLAB interpreter can execute the code examples as shown.No additional libraries need to be acquired and installed. Moreover,my examples rarely use M ATLAB’s toolboxes,relying heavily on its basic functionality.Readers should note that the code examples used throughout the book are designed for conceptual simplicity,rather than optimized for speed or memory usage.I encourage readers to rework my M ATLAB examples to achieve greater performance or even implement them in other languages.I offer my thanks and appreciation to all those who have paved the way for this work,particularly Glenn Tyler,David Fried,and Phillip Roberts at the Optical Sciences Company and Steve Coy at MZA Associates Corporation.In1982,Fried and Tyler wrote a technical report describing methods of simulating optical wave propagation and related sampling constraints.A few years later,Roberts wrote a follow-on report giving another clear,nicely detailed description of one-step,two-step,and angular spectrum propagation methods.More recently,Coy wrote a tech-nical report that gives a very nice description of the relationship between sampling requirements propagation geometry.These reports formed the beginnings of Goda’s notes and eventually this book.Also,thanks to those who answered my questions about wave-optics simula-tions while I was a student at UD and then while I taught the wave-optics simula-tion course as a professor at AFIT:Jeffrey Barchers,Troy Rhoadarmer,Terry Bren-nan,and Don Link.These gentlemen are experienced and accomplished researcherswhose advice was very much appreciated.Additionally,thanks to Michael Havrilla for his help with the basic electrodynamics in Ch.1.Special thanks to Matthew Goda for his foundational work in the course and its notes.Without him,this book would not be possible.He made much of the material in this book accessible to dozens of students who went on to do great things for the U.S.Air Force.Finally,I’d like to thank all those students who helpedfind errors in the drafts of this book and whose inquisitive nature caused me to refine and add material along the way.Jason SchmidtJune,2010Chapter1Foundations of Scalar Diffraction TheoryLight can be described by two very different approaches:classical electrodynam-ics and quantum electrodynamics.In the classical treatment,electric and magnetic fields are continuous functions of space and time,and light comprises co-oscillating electric and magnetic wavefields.In the quantum treatment,photons are elemen-tary particles with no mass nor charge,and light comprises one or more photons. There is rigorous theory behind each approach,and there is experimental evidence supporting both.Neither approach can be dismissed,which leads to the wave-particle duality of light.Generally,classical methods are used for macroscopic properties of light,while quantum methods are used for submicroscopic proper-ties of light.This book describes macroscopic properties,so it deals entirely with classi-cal electrodynamics.When the wavelengthλof an electromagnetic wave is very small,approaching zero,the waves travel in straight lines with no bending around the edges of objects.That is realm of geometric optics.However,this book treats many situations in which geometric optics are inadequate to describe observed phe-nomena like diffraction.Therefore,the starting point is classical electrodynamics with solutions provided by scalar diffraction theory.Geometric optics is treated briefly in Sec.6.5.1.1Basics of Classical ElectrodynamicsClassical electrodynamics deals with relationships between electricfields,magnetic fields,static charge,and moving charge(i.e.,current)in space and time based on the macroscopic properties of the materials in which thefields exist.We define each quantity here along with some basic relationships.This introduces the reader to the quantities in Maxwell’s equations,which describe how electrically charged particles and objects give rise to electric and magneticfields.Maxwell’s equations are introduced here in their most general form,and then the discussion focuses on a specific case and solutions for oscillating electric and magneticfields,which light comprises.12Chapter 11.1.1Sources of electric and magneticfieldsElectric charge,measured in coulombs,is a fundamental property of elementary particles and bulk materials.Classically,charge may be positive,negative,or zero. Further,charge is quantized,specifically the smallest possible nonzero amount of charge is the elementary charge e=1.602×10−19C.All nonzero amounts of charge are integer multiples of e.For bulk materials,the integer may be very large so that total charge can be treated as continuous rather than discrete.We denote the volume density of free charge,measured in coulombs per cubic meter,byρ(r,t), where r is a three-dimensional spatial vector,and t is time.Moving charge density is called free volume current density J(r,t).V olume current density is measured in Ampères per square meter(1A=1C/s).This represents the time rate at which charge passes through a surface of unit area.Finally,charge is conserved,meaning that the total charge of any system is constant.This is mathematically stated by the continuity equation=0.(1.1)∇·J(r,t)+∂ρ(r,t)∂tAlmost every material we encounter in life is composed of many,many atoms each with many positive and negative ually,the numbers of positive and negative charges are equal or nearly equal so that the whole material is electrically neutral.Still,such a material can give rise to electric or magneticfields when the to-tal charge and free current are zero.If the distribution of charge is not homogeneous or if the charges are circulating in tiny current loops,fields could be present.The separation of charge is described by the electric dipole moment,which is the amount of separated charge times the separation distance.If a bulk material has its charge arranged in many tiny dipoles,it is said to be electrically polarized.The volume polarization density P(r,t)is the density of electric dipole moments per unit volume,measured in coulombs per square meter.Magnetization is a similar concept for moving charge.Charge circulating in a tiny current loop is described by magnetic dipole moment,which is the circulat-ing current times the area of the loop.When a bulk material has internal current arranged in many tiny loops,it is said to be magnetized.The volume magnetiza-tion density M(r,t)is the density of magnetic dipole moments per unit volume, measured in Ampères per meter.1.1.2Electric and magneticfieldsWhen a hypothetical charge,called a test charge,passes near a bulk material that has non-zeroρ,J,P,or M,the charge experiences a force.This interaction is char-acterized by two vectors E and B.The electromagnetic force F on a test particle at a given point and time is a function of these vectorfields and the particle’s charge q and velocity v.The Lorentz force law describes this interaction asF=q(E+v×B).(1.2)If this empirical statement is valid(and,of course,countless experiments over the course of centuries have shown that it is),then two vectorfields E and B are thereby defined throughout space and time,and these are called the“electricfield”and “magnetic induction.”1Eq.(1.2)can be examined in a little more detail to provide more intuitive defini-tions of thesefields.The electricfield is the amount of force per unit of test charge when the test charge is stationary,given byE=limq→0+Fq v=0.(1.3)This is called a push-and-pull force because the force is in either the same or op-posite direction as thefield,depending on the sign of the charge.Electricfield is measured in units of volts per meter(1V=1N m/C).The magneticfield is related to the amount of force per unit test charge given byv×B=limq→0+F−q Eq v=0.(1.4)The force due to a magneticfield is called deflective because it is perpendicular to the particle’s velocity,which deflects its trajectory.Magneticfield is measured in units of Tesla[1T=1N s/(C m)].With this understanding of thefields,they now need to be related to the sources. This was accomplished through centuries of experimental measurements and theo-retical and intuitive insight,resulting in∇×E+∂B∂t=0(1.5)∇×B−µ0 0∂E∂t=µ0 J+∂P∂t+∇×M .(1.6)These are two of Maxwell’s equations,the former being Faraday’s law and the latter being Ampère’s law with Maxwell’s correction.In Eq.(1.6),the sources on the right hand side include the free current J and two terms due to bound currents. These are the polarization current∂P/∂t and the magnetization current∇×M.These equations can be written in a more functionally useful form.Eq.(1.6) can be rewritten as∇× Bµ0−M =J+∂∂t( 0E+P).(1.7) Making the definitionsD= 0E+P(1.8)H=Bµ0−M(1.9)Foundations of Scalar Diffraction Theory3introduces the concepts of electric displacement D and magnetic field H ,which are fields that account for the medium’s response to the applied fields.Now,the working form of these Maxwell equations becomes∇×E =−∂B∂t (1.10)∇×H =J +∂D ∂t .(1.11)Further,when these are combined with conservation of charge expressed in Eq.(1.1),this leads to∇·∇×H =∇·J +∂∂t ∇·D (1.12)=−∂ρ∂t +∂∂t∇·D (1.13)=0.(1.14)Focusing on the right-hand side,∂∂t(∇·D −ρ)=0(1.15)∇·D −ρ=f (r ),(1.16)where f (r )is an unspecified function of space but not time.Causality requires that f (r )=0before the source is turned on,yielding Coulomb’s law:∇·D =ρ.(1.17)Similar manipulations yield∇·B =0.(1.18)This indicates that magnetic monopole charges do not exist.Finally,Eqs.(1.10),(1.11),(1.17),and (1.18)constitute Maxwell’s equations.1In this model of macroscopic electrodynamics,Eqs.(1.10)and (1.11)are two independent vector equations.With three scalar components each,these are six in-dependent scalar equations.Unfortunately,given knowledge of the sources,there are four unknown vector fields D ,B ,H ,and E .Each has three scalar components for a total of twelve unknown scalars.With so many more unknown field compo-nents than equations,this is a poorly posed problem.The key is to understand the medium in which the fields exist.This produces a means of relating P to E and M to H ,which amount to six more scalar equations.For example,in simple media (linear,homogeneous,and isotropic),P = 0χe E(1.19)M =χm H ,(1.20)4Chapter 1Foundations of Scalar Diffraction Theory5 whereχe is the electric susceptibility of the medium andχm is its magnetic sus-ceptibility.Substituting these into Eqs.(1.8)and(1.9)yieldsD= 0E+P(1.21)= 0(1+χm)E(1.22)= E(1.23) andB=µ0(H+M)(1.24)=µ0(1+χm)H(1.25)=µH,(1.26) where =(1+χe) 0is the electric permittivity andµ=(1+χm)µ0is the magnetic permeability of the medium.Now,this simplifies Eqs.(1.10)and(1.11) so that∇×E=−µ∂H∂t(1.27)∇×H=J+ ∂E∂t.(1.28) Now,there are still six equations but only six unknowns(as long as the free current density J is known).Finally,with a proper understanding of the materials,this is a well posed problem.1.2Simple Traveling-Wave Solutions to Maxwell’s Equations There are many solutions to Maxwell’s equations,but there are only a few that can be written in closed form without an integral.This section begins with transforming Maxwell’s four equations into two uncoupled wave equations.It continues with a few specific simple solutions such as the infinite-extent plane wave.A more general solution is left to the next section.1.2.1Obtaining a wave equationThis book deals with optical wave propagation through linear,isotropic,homoge-neous,nondispersive,dielectric media in the absence of source charges and cur-rents.In this case,the media discussed throughout the remainder of this book have=a scalar,independent ofλ,r,t(1.29)µ=µ0(1.30)ρ=0(1.31)J=0.(1.32)Taking the curl of Eq.(1.27)yields∇×(∇×E )=−µ0∂∂t (∇×H ).(1.33)Then,substituting in Eq.(1.28)gives∇×(∇×E )=−µ0 ∂2∂t 2E .(1.34)Now,applying the vector identity ∇×(∇×E )=∇(∇·E )−∇2E leads to∇(∇·E )−∇2E =−µ0 ∂2∂t 2E .(1.35)Finally,substituting in Eqs.(1.17)and (1.23),and keeping in mind that is inde-pendent of position results in a wave differential equation:∇2E −µ0 ∂2∂t 2E =0.(1.36)Similar manipulations beginning with the curl of Eq.(1.28)yield∇2B −µ0 ∂2∂t 2B =0.(1.37)When the Laplacian is used on the Cartesian components of E and B ,the result is six uncoupled but identical equations of the form∇2−µ0 ∂2∂t2 U (x,y,z )=0,(1.38)where the scalar U (x,y,z )stands for any of the x -,y -or z -directed components of the vector fields E and B .At this point,we can define index of refraction n = 0(1.39)and the vacuum speed of light c =1√µ0 0(1.40)so that∇2−n 2c 2∂2∂t 2 U (x,y,z )=0.(1.41)The electric and magnetic fields that compose light are traveling wave fields.There-fore,fields with harmonic time dependence exp (−i 2πνt )(where νis the wave 6Chapter 1frequency)are the types of solutions sought for the purposes of this book.When this is substituted into Eq.(1.41),the result is∇2+ 2πnνc 2 U=0.(1.42) Typically,the wavelength is given byλ=c/ν,and the wavenumber is defined as k=2π/λso that ∇2+k2n2 U=0.(1.43) This is the Helmholtz equation,and it appears in many other branches of physics including thermodynamics and quantum mechanics.At this point,we can dispense with the time dependence since it is the same for all solutions of the Helmholtz equation.From this point forward,thefield U(x,y,z)refers to the phasor por-tion of the opticalfield(i.e,no time dependence).Further,we define the units of U(x,y,z)to be square-root watts per meter(1W=1J/s=1N m/s)so that optical irradiance I=|U|2is in units of watts per meter squared.The value of the electric field or magnetic induction can always be obtained by a simple conversion of units.1.2.2Simple traveling-wavefieldsThere are several simple traveling-wavefields that are useful in this book.These are planar,spherical,and Gaussian-beam waves.With each of these solutions,thefield at all points always maintains its planar,spherical,or Gaussian-beam form,and pa-rameters like radius of curvature change in a simple manner as the wave propagates. The next section on scalar diffraction theory handles more general cases.A planar wave is the simplest possible traveling wave.It has uniform amplitude and phase in any plane perpendicular to its direction of propagation.More gener-ally,when the optical axis is not along the direction of propagation,a planar wave field is given byU P(r)=A exp(i k·r),(1.44) where A is the amplitude of the wave andk=2πλ(αˆx+βˆy+γˆz)(1.45)is the wavevector with direction cosines given byα,β,andγ.Then,making the direction cosines more explicit,U P(r)=A exp i2πλ(αx+βy+γz) .(1.46)This wave travels at an angle cos−1αfrom the x-axis and cos−1βfrom the y-axis as shown in Fig.1.1.Foundations of Scalar Diffraction Theory7yzFigure 1.1Depiction of direction cosines α,β,and γ.A spherical wave is the next simplest wave field.It has a wavefront that is spherical in shape,and it is either diverging or converging.The energy of the wave is spread uniformly over a spherical surface with area given by 4πR 2,where R is the wavefront radius of curvature.Conservation of energy requires that the ampli-tude is accordingly proportional to R −1.A spherical wave is given byU S (r )=A exp [ikR (r )]R (r ).(1.47)If the center of the sphere is located at r c =(x c ,y c ,z c ),then at an observation point r =(x,y,z ),the radius of curvature is given by R (r )= (x −x c )2+(y −y c )2+(z −z c )2.(1.48)Often in optics,attention is restricted to regions of space that are very close to the optical axis.This is called the paraxial approximation,and assuming propagation in the positive z direction,this approximation is mathematically written ascos −1α 1(1.49)cos −1β 1.(1.50)With this approximation,we eliminate the square root by expanding it as a Taylor series and keeping only the first two terms,yielding R (r ) ∆z 1+12 x −x c ∆z 2+12 y −y c ∆z2 ,(1.51)where we have defined ∆z =|z −z c |.With the paraxial approximation,a spherical wave is approximatelyU S (r ) A e ik ∆z ∆z e i k 2∆z [(x −x c )2+(y −y c )2].(1.52)8Chapter 1Onefinal simple traveling wave often encountered in optics is the Gaussian-beam wave.It has a Gaussian amplitude profile and“paraxially spherical”wave-front.The full derivation of the Gaussian-beam solution invokes the paraxial ap-proximation along the way.Such a derivation can be found in common laser text-books like Refs.2–3.This solution is given byU G(r)=Aq(z)exp ik x2+y22q(z) ,(1.53)where1 q(z)=1R(z)+iλπW2(z)(1.54)and the beam radius and wavefront radius of curvature are given byW2(z)=W20 1+ λzπW20 2 (1.55)R(z)=z 1+ πW20λz 2 ,(1.56)where W0is the minimum spot radius.At any point along the z axis,W(z)is the 1/e radius of thefield amplitude.Also,by this convention,W(0)=W0so that the minimum spot radius is located at z=0.1.3Scalar Diffraction TheoryOften,the optical source is not a simple planar,spherical,nor Gaussian-beam wave. For more general cases,we must use more sophisticated means to solve the scalar Helmholtz equation.This means taking advantage of Green’s theorem with clever use of boundary conditions.This process is not discussed in detail here,but the interested reader should consult books like Refs.4–5for a detailed treatment.The geometry for this more general case is shown in Fig.1.2.In thisfigure, the coordinates are r1=(x1,y1)in the source plane and r2=(x2,y2)in the observation plane.The distance between the two planes is∆z.Thefigure illus-trates the basic problem:given the source-plane opticalfield U(x1,y1),what is the observation-planefield U(x2,y2)?The solution is given by the Fresnel diffraction integralU(x2,y2)=e ik∆ziλ∆z∞−∞∞−∞U(x1,y1)e i k2∆z[(x1−x2)2+(y1−y2)2]dx1dy1.(1.57)Note that this is not the most general solution.In fact,it is a paraxial approximation, but it is general enough and accurate enough for the purposes of this book. Foundations of Scalar Diffraction Theory9。
Nonlinear superposition formula for N=1 supersymmetric KdV Equation
a r X i v :n l i n /0212002v 2 [n l i n .S I ] 21 M a r 2003Nonlinear superposition formula for N =1supersymmetric KdV Equation Q.P.Liu and Y.F.Xie Department of Mathematics,China University of Mining and Technology,Beijing 100083,China.Abstract In this paper,we derive a B¨a cklund transformation for the supersymmetric Korteweg-de Vries equation.We also construct a nonlinear superposition formula,which allows us to rebuild systematically for the supersymmetric KdV equation the soliton solutions of Carstea,Ramani and Grammaticos.The celebrated Korteweg-de Vries (KdV)equation was extended into super frame-work by Kupershmidt [3]in 1984.Shortly afterwards,Manin and Radul [7]proposed another super KdV system which is a particular reduction of their general supersymmet-ric Kadomstev-Petviashvili hierarchy.In [8],Mathieu pointed out that the super version of Manin and Radul for the KdV equation is indeed invariant under a space supersymmetric transformation,while Kupershmidt’s version does not.Thus,the Manin-Radul’s super KdV is referred to the supersymmetric KdV equation.We notice that the supersymmetric KdV equation has been studied extensively in lit-erature and a number of interesting properties has been established.We mention here the infinite conservation laws [8],bi-Hamiltonian structures [10],bilinear form [9][2],Darboux transformation [6].By the constructed Darboux transformation,Ma˜n as and one of us calculated the soli-ton solutions for the supersymmetric KdV system.This sort of solutions was also obtained by Carstea in the framework of bilinear formalism [1].However,these solutions are char-acterized by the presentation of some constraint on soliton parameters.Recently,using super-bilinear operators,Carstea,Ramani and Grammaticos [2]constructed explicitly new two-and three-solitons for the supersymmetric KdV equation.These soliton solutions are interesting since they are free of any constraint on soliton parameters.Furthermore,the fermionic part of these solutions is dressed through the interactions.In addition to the bilinear form approach,B¨a cklund transformation (BT)is also a powerful method to construct solutions.Therefore,it is interesting to see if the soliton solutions of Carstea-Ramani-Grammaticos can be constructed by BT approach.In this paper,we first construct a BT for the supersymmetric KdV equation.Then,we derive a nonlinear superposition formula.In this way,the soliton solutions can be producedsystematically.We explicitly show that the two-soliton solution of Carstea,Ramani and Grammaticos appears naturally in the framework of BT.To introduce the supersymmetric extension for the KdV equation,we recall some terminology and notations.The classical spacetime is(x,t)and we extend it to a super-spacetime(x,t,θ),whereθis a Grassmann odd variable.The dependent variable u(x,t) in the KdV equation is replaced by a fermionic variableΦ=Φ(x,t,θ).Now the super-symmetric KdV equation reads asΦt−3(ΦDΦ)x+Φxxx=0,(1)where D=∂∂x is the superderivative.Mathieu found the following supersymmetricversion of Gardner type mapΦ=χ+ǫχx+ǫ2χ(Dχ),(2) whereǫis an ordinary(bosonic)parameter.It is easy to show thatχsatisfies the following supersymmetric Gardner equationχt−3(χDχ)x−3ǫ2(Dχ)(χDχ)x+χxxx=0.(3) This map was used in[8]to prove that there exists an infinite number of conservation laws for the supersymmetric KdV equation(1).In the classical case,Gardner type of map was studied extensively by Kupershmidt[4].It is well known that such map may be used to construct interesting BT.We will show that it is also the case for the supersymmetric KdV equation.We notice that the supersymmetric Gardner equation(3)is invariant underǫ→−ǫ. The new solution of the supersymmetric KdV equation corresponding to with−ǫis denoted as˜Φ.Thus we have˜Φ=χ−ǫχx+ǫ2χ(Dχ).(4) From above relations(3-4),wefindΦ−˜Φ=2ǫχx,(5)Φ+˜Φ=2χ+2ǫχ(Dχ).(6) Let us introduce the potentials as followsΦ=Ψx,˜Φ=˜Ψx,thus,the equation(5)provides usχ=12(Ψ−˜Ψ)(DΨ−D˜Ψ),(8)whereλ=1/ǫis the B¨a cklund parameter.The transformation(8)is in fact the spatial part of BT.Its temporal counterpart can be easily worked out.We also remark here that the BT is reduced to the well known BT for the classical KdV equation ifη=0,as it should be.A BT can be used to generate special solutions.If we start with the trivial solution ˜Ψ=0,we obtain2a(ζ+θλ)eλx−λ3tΨ=−(Ψ1−Ψ0)(DΨ1−DΨ0),(10)2and1(Ψ0+Ψ2)x=λ2(Ψ2−Ψ0)+(Ψ3−Ψ1)(DΨ3−DΨ1),(12)2and1(Ψ2+Ψ3)x=λ1(Ψ3−Ψ2)+Subtraction (10)form (11),we have(Ψ2−Ψ1)x =λ2Ψ2−λ1Ψ1+(λ1−λ2)Ψ0+12Ψ2(D Ψ0)−12Ψ1(D Ψ1)+12Ψ0(D Ψ1),(14)similarly,from (12)and (13)we have(Ψ2−Ψ1)x = λ1−λ2+12(D Ψ2) Ψ3+12Ψ2(D Ψ2)−12(D Ψ1)−12(Ψ1−Ψ2)[(D Ψ3)+2λ1+2λ2−(D Ψ0)]=0.(16)The equation (16)is a differential equation for Ψ3.Solving it we obtainΨ3=Ψ0−(λ1+λ2)(Ψ1−Ψ2)λ1−λ2+v 1−v 2−(λ1+λ2)(η1−η2)(η1,x −η2,x )(λ1−λ2+v 1−v 2).It is clear that our nonlinear superposition formula reduces to the well-known superposition formula for the KdV as it should be.The advantage to have a superposition formula is that it is an algebraic one and can be used easily to find solutions.Using the solutions (9)as our seeds,we may construct a 2-soliton solution of (1)by means of our superposition formula.Indeed,letΨ0=0,Ψ1=−2a 1(ζ1+θλ1)e λ1x −λ31t1+a 2e λ2x −λ32tthen from our nonlinear superposition formula (17),we obtainΨ3=2 ζ1a 1e δ1−ζ2a 2e δ2+(ζ1−ζ2)a 1a 2e δ1+δ2+θ(λ1a 1e δ1−λ2a 2e δ2+(λ1−λ2)a 1a 2e δ1+δ2)whereδi=λi x−λ3i t+θζi(i=1,2).Now,takingλ1>λ2,a1=−λ1−λ2λ1+λ2we recover the2-soliton solution foundfirst by Carstea,Ramani and Grammaticos[2].As in the classical KdV case[11],we generate this2-soliton from a regular solution and a singular solution.We could continue this process to build the higher soliton solutions and the calculation will be tedious but straightforward.Acknowledgment The work is supported in part by National Natural Scientific Foun-dation of China(grant number10231050)and Ministry of Education of China. References[1]Carstea A S2000Extension of the bilinear formalism to supersymmetric KdV-typeequations Nonlinearity131645.[2]Carstea A S,Ramani A and Grammaticos B2001Constructing the soliton solutionsfor the N=1supersymmetric KdV hierarchy Nonlinearity141419.[3]Kupershmidt B A1984A super Korteweg-de Vries equation Phys.Lett.102A213.[4]Kupershmidt B A1981On the nature of Gardner transformation J.Math.Phys.22449;Kupershmidt B A1983Deformations of integrable systems Proc.R.Soc.Irish 83A45.[5]Liu Q P1995Darboux transformation for the supersymmetric KdV equations Lett.Math.Phys.35115.[6]Liu Q P and Ma˜n as M1997Darboux transformation for the Mann-Radul supersym-metric KdV equation Phys.Lett.B394337;Liu Q P and Ma˜n as M in Supersymmetry and Integrable Systems eds.H.Aratyn et al Lecture Notes in Physics502(Springer).[7]Manin Yu I and Radul A O1985A supersymmetric extension of the Kadomtzev-Petviashvili hierarchy Commun.Math.Phys.9865.[8]Mathieu P1988Supersymmetric extension of the Korteweg-de Vries equation J.Math.Phys.292499.[9]McArthur I N and Yung C M1993Hirota bilinearfform for the super KdV hierarchyMod.Phys.Lett.8A1739.[10]Oevel W and Popowicz Z1991The bi-Hamiltonian structure of fully supersymmetricKorteweg-de Vries systems Commun.Math.Phys.139441;Figueroa-O’Farril J,Mas J and Ramos E1991Integrability and biHamiltonian structure of the even order sKdV hierarchies Rev.Math.Phys.3479.[11]Wahlquist H D and Estabrook F B1974B¨a cklund transformation for solutions of theKorteweg-de Vries equation Phys.Rev.Lett.311386.。
参考文献的标准格式
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题名[J]。
刊名,年,卷(期):起止页码(任选)。
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题名[M]。
出版地:出版者,出版年,起止页码。
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析出文献题名[A]。
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发布年。
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电子文献题名。
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专著(M);论文集(C);报纸文章(N);期刊文章(J)学位论文(D);报告(R);标准(S)专利(P)(8)未定义类型的文献(文献类型标识:Z)[序号] 主要责任者。
文献题名[Z]。
出版地:出版者,出版年。
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范例二:一、参考文献的类型 >>详细国家标准参考文献(即引文出处)的类型以单字母方式标识,具体如下:M——专著 C——论文集 N——报纸文章 J——期刊文章 D——学位论文R——报告对于不属于上述的文献类型,采用字母“Z”标识。
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论文中参考文献和图、表的标准格式
论文中参考文献和图、表的标准格式1.参考文献的作用着录参考文献是科技论文写作的传统贯例和必要内容。
首先,它体现了科学的严肃性、继承性和对他人劳动的尊重。
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具体讲,有以下几种情况。
参考文献类型:专著[M],论文集[C],报纸文章[N],期刊文章[J],学位论文[D],报告[R],标准[S],专利[P],论文集中的析出文献[A]电子文献类型:数据库[DB],计算机[CP],电子公告[EB]电子文献的载体类型:互联网[OL],光盘[CD],磁带[MT],磁盘[DK](1)文内的标注视则①引文写出原著者时,序号应置于著者姓名的右上角。
如在谈到当前我国优质烤烟生产中存在的问题时,朱尊权[2]指出:……②不写出著者时,序号应置于引文之后右上角。
如“营养不良.发育不全,成熟不够.烘烤不当”[3],这“四不”问题是符合我国烤烟生产实际情况的。
③当将参考文献序号作为文句的组成部分时,不用角码序号,而以正文形式用方括号序号列出。
如烟草增香剂的制各方法见文献[2]。
④当引用多篇文献时,只须将各篇文献的序号在一个角码内全部列出,各序号间用逗号隔开;如通连续序号,应在标注起止序号间加“~”连接。
如早期的研究结果[2,5,7~9]表明,……(2)文后的着录规则①书籍的基本著录项目和着录规则[序号]著者.书名.版本,出版地:出版者,出版年.页次.示例[1]管雨霖,张凤英,马超群,等.烟草病害诊断虫害识别及防治[M].北京:农业出版社,1989.78-81.②期刊的基本著录项目和着录规则[序号]著者.题(篇)名.刊名,出版年,卷(期)号:页次.示例[1]朱尊权.论当前我国优质烤烟生产技术导向[J].烟草科技,1994,(1):2-3.[2]金龙林.关于在论文中标往参考文献顺序码的位置问题[J].编辑学报,1994,6(4):240-241.③专利文献的基本著录项目和着录规则[序号]专利申请者.专利题名.专利国别,专利文献种类,专利号.出版日期.示例[1]孙中培,刘清,段完晶.烟草薄片用烟杆纤维物质.中国专利,发明,CN1074592A.1993-07-28.[2]牛聪阳,刘立全,荆海强.固体物料造粒机.中国专利,实用新型,ZL93 2 24039.9.1995-02-12.④报纸的基本著录项目和通用格式[序号]著者.题(篇)名.报纸名,出版年.月.日(版位).示例[1]刘彩望.保护烟农利益稳定烟叶生产:河南省提高优质烟奖励标准.东方烟草报,1995.1.25(1).A:专著、论文集、学位论文、报告[序号]主要责任者.文献题名[文献类型标识].出版地:出版者,出版年.起止页码(可选)[1]刘国钧,陈绍业.图书馆目录[M].北京:高等教育出版社,1957.15-18.B:期刊文章[序号]主要责任者.文献题名[J].刊名,年,卷(期):起止页码[1]何龄修.读南明史[J].中国史研究,1998,(3):167-173.[2]OU J P,SOONG T T,et al.Recent advance in research on applications of passi ve energy dissipation systems[J].Earthquack Eng,1997,38(3):358-361.C:论文集中的析出文献[序号]析出文献主要责任者.析出文献题名[A].原文献主要责任者(可选).原文献题名[C].出版地:出版者,出版年.起止页码[7]钟文发.非线性规划在可燃毒物配置中的应用[A].赵炜.运筹学的理论与应用——中国运筹学会第五届大会论文集[C].西安:西安电子科技大学出版社,1996.468.D:报纸文章[序号]主要责任者.文献题名[N].报纸名,出版日期(版次)[8]谢希德.创造学习的新思路[N].人民日报,1998-12-25(10).E:电子文献[文献类型/载体类型标识]:[J/OL]网上期刊、[EB/OL]网上电子公告、[M/CD]光盘图书、[DB/OL]网上数据库、[DB/MT]磁带数据库[序号]主要责任者.电子文献题名[电子文献及载体类型标识].电子文献的出版或获得地址,发表更新日期/引用日期[12]王明亮.关于中国学术期刊标准化数据库系统工程的进展[EB/OL].http://www.cajcd. /pub/wml.html,1998-08-16/1998-10-01.[8]万锦.中国大学学报文摘(1983-1993).英文版[DB/CD].北京:中国大百科全书出版社,1996.参考文献规范格式一、参考文献的类型参考文献(即引文出处)的类型以单字母方式标识,具体如下:M——专著C——论文集N——报纸文章J——期刊文章D——学位论文R——报告对于不属于上述的文献类型,采用字母“Z”标识。
河南省信阳市浉河区信阳高级中学2023-2024学年高一下学期5月期中英语试题(含答案)
信阳高中北湖校区2023-2024学年高一下期05月测试(二)英语试题分值:150分时间:120分钟注意事项:1.答题前请填好自己的姓名,班级,考号等信息2.请将答案正确填写在答题卡上一、单词汉译英、英译汉(共20小题;每小题1.5分,共30分)1.g adj.全球的;全世界的2.a adv.每年;一年一度地3.m n.大多数4.d v.消失,不见5.o adj.普通的;平常的6.c adj.当前的,现在的7.f adj.以前的,从前的8.o vt.克服(困难);控制情感9.s n.继续生存,幸存10.p n.建议,提议11.solution n.12.bother vi&vt.13.firm adj.14.involve vt.15.profit n.16.contented adj.17.determination n.18.slim adj.19.destination n.20.indicate vt.二、阅读理解(共两节,共20小题,每小题2.5分,满分50分)第一节(共15小题;每小题2.5分,共37.5分)AGreen Line Performing Arts CenterUpcoming Programs:First Monday Jazz Series:CrosswindMonday Feb 4|7-9 pmFirst Monday Jazz is a free monthly event showcasing local Chicago jazz artists.Green Light Series:South Side Story TimeSunday Feb 17|10-11 amBring your kids to listen,learn,sing,dance,and interact!South Side Story Time is a small gathering that focuses on readings for its young attendees along with the chance for their parents to socialize.Open to families with children of all ages.Sistergirls and Freedom Fighters:Stories in Celebration of Women's Power and Grace Wednesday Feb 20|7-8 pmJoin us for an evening of storytelling featuring the dynamic singing,in the Spirit by Emily Hooper Lansana.This performance will highlight a range of stories that demonstrate women's creative and political genius from folk heroines to Nobel Peace Prize winners.Family Saturdays:Art togetherEvery 1st Saturday of the Month|3-5 pmExplore your child's artistic curiosity with hands-on art workshops designed to stimulate creativity and play.These interdisciplinary workshops are exciting for the entire family,offering activities from music to arts and e to learn something new!Appropriate for families with children.Registration(注册)is encouraged.Follow Arts +Public Life on Facebook for more event details and a full list of all upcomingperformances.21.When can people enjoy jazz in February?A.At 8 pm every first Monday. C.At 7 pm every first Wednesday.B.At 4 pm every other Saturday.D.At 9 pm every other Monday.22.What do we know about Sistergirls and Freedom Fighters?A.It lasts two hours.C.It is a prize-winning performance. B.It is organized by Emily.D.It celebrates women's achievements.23.What do Green Light Series and Family Saturdays have in common?A.Activity typesC.Target participants.B.Event frequencyD.Registration requirements. BI used to believe that only words could catch the essence of the human soul.The literary(文学的)works contained such distinct stories that they shaped the way we saw the world.Words were what composed the questions we sought to uncover and the answers to those questions themselves.Words were everything.That belief changed.In an ordinary math class,my teacher posed a simple question:What's 0.99 rounded to the nearest whole number?Easy.When rounded to the nearest whole number,0.99 =1.Somehow,I thought even though 0.99 is only 0.01 away from 1,there's still a 0.01 difference.That means even if two things are only a little different,they are still different,so doesn't that make them completely different?My teacher answered my question by presenting another equation(等式):1=0.9,which could also be expressed as 1=0.99999...repeating itself without ever ending.There was something mysterious but fascinating about the equation.The left side was unchangeable,objective:it contained a number that ended.On the right was something endless,number repeating itself limitless times.Yet,somehow,these two opposed things were connected by an equal sign.Lying in bed,I thought about how much the equation paralleled our existence.The left side of the equation represents that sometimes life itself is so unchangeable and so clear.The concrete,whole number of the day when you were born and the day when you would die.But then there is that gap in between life and death.The right side means a time and space full of limitless possibilities,and endless opportunities into the open future.So that's what life is.Objective but imaginative.Unchangeable but limitless.Life is an equation with two sides that balances itself out.Still,we can't ever truly seem to put the perfect words to it.So possibly numbers can express ideas as equally well as words can.For now,let's leave it at that:1=0.99999...and live a life like it.What does the author emphasize about words in paragraph 1?A.Their wide variety. C.Their expressive power.B.Their literary origins D.Their distinct sounds.25.What made the author find the equation fascinating?A.The repetition of a number.B.The difference between the two numbers.D.The way two different numbers are equal.C.The question the teacher raised.26.Which of the following can replace the underlined word paralleled"in paragraph 6?A.Measured.posed.C.Mirrored.D.Influenced.27.What does the author think of“1=0.9”?A.They uncover the meaning of life.C.They are useful in learning maths.B.They are reliable in expressing ideas.D.They give limited possibilities.CDuring space missions,astronauts can experience a loss of some of the inner structural support in their bones.For trips in space lasting at least six months,that loss is equal to about 20 years of aging.Luckily,a new study finds a year back on Earth rebuilds half of the strength lost in the affected bone.Exercise scientist Leigh Gabel was part of a team that tracked 17 astronauts,each of whom had spent four to seven months in space.The team measured the 3-D structure of bone.They focused on the structure of the tibia(胫骨)and the lower-arm bone.The researchers took images of the bones3times—before spaceflight and again six months and one year later when the astronauts returned home from space.From these pictures,Gabel's team calculated an astronaut's bone strength and density(密度)at each of those times.What did hey find through comparison of the pictures?Astronauts in space for less than six months regained their preflight(起飞前的)bone strength after a year back on Earth.But those who stayed in space longer suffered permanent bone loss in their tibias.That loss was equal to a decade of aging.The lower arm bones showed almost no loss.Tat was likely because these aren’t weigh-bearing bones on Earth,Gabel explains.In fact,those arms can get bigger workout in space than on Earth as astronauts use them to move around their craft by pushing off handles and doors.“Increasing weight-lifing exercises in space could help alleviate (解)bone loss in the legs,”says Steven Boyd,also in exercise scientist.“With longer spaceflight,we can expect bigger bone loss-and probably a bigger problem with recovery,”says physiologist Laurence Vico.“Space agencies should also consider other bone health measures,such as nutrition,to reduce bone loss and increase bone formation.”28.Why did Gabel's team take pictures at different times?A.To offer evidence for their predictions.B.o show their respect for the astronauts.C.To compare the changes in the astronauts' bones.D.To find out the proper length of staying in space for astronauts.29.Which of the following may Gabel agree with?A.A spaceflight in less than half a year does no harm to astronauts.B.Astronauts coming back from a spaceflight look much older.C.Astronauts can aybid bone loss through doing enough exercise.D.There is almost no difference in the astronauts' lower-arm bones.30.What can we conclude from this text?A.People on Earth never suffer bone loss.B.The finding of the new study is good news for astronauts.C.The 17 astronauts knew the bone loss before their spaceflights.D.Astronauts can regain their bone strength as soon as they return to Earth.31.What does the text mainly talk about?A.ow to prevent bone loss in space.B.Problems faced by astronauts in space.C.Astronauts' suffering from bone loss in space.D.Astronauts' contributions to the development of science.DThe innovation is part of research into brain-computer interfaces(接口)to help improve the lives of people with disabilities.The researchers included machine learning capabilities with their brain-computer interface,making it a one-size-fits-all solutionTypically,these devices require extensive adjustment for each user-every brain is different,both for healthy and disabled users and that has been a major obstacle to mainstream adoption.This new solution can quickly understand the needs of an individual subject and self-adjust through repetition.That means multiple patients could use the device without needing to adjust it for better functioning.In a clinical setting,the subjects wear a cap packed with electrodes(电极)that is connected to a computer.The electrodes gather data by measuring electrical signals from the brain,and the decoder translates the brain signals into commands,which are used to control devices or applications.In this case,the decoded signals are translated into actions in a car racing game and a simpler task involving balancing a digital bar.Subjects were trained simultaneously for both the simpler bar game and the more complex car racing game,thus improving their brain function.This project used 18 subjects with no motor disabilities.As they continue down this road,they will test this on people with motor disabilities to apply it to larger groups in clinical settings.“To achieve this,we need to improve our technology to make it easier to use,'Millan.a professor in the University of Texas says.On the side of translating the research,Millan and his team continue to work on a wheel chair that users can drive with the brain-computer interface.At the South by Southwest Conference and Festivals this month,the researchers showed off another potential use of the technology:controlling two rehabilitation(康复)robots for the hand and arm.This was not part of the new paper but a sign of where this technology could go in the future.“We'll continue down this path wherever it takes us in the pursuit of helping people.”Millan says.32.Who will benefit the most from the Brain-Computer Interface innovation?A.People with physical disabilitiesB.Businessmen selling wheelchairsC.Students seeking academic improvement.D.Athletes seeking performance enhancement.33.What is the main advantage of the new solution?A.Faster adjustment process C.I proved mainstream adoption.B.Decreased need for adjustingD.Quick understanding of commands34.What is the function of electrodes?A.Translating signals C.Controlling devicesB.Measuring brain signals D.Enhancing brain function.35-What is the probable focus of Millan and his team's future work?A.Exploring hand and arm rehabilitation.B.Showcasing technology at conferences.C.Translating and publishing research papers.D.Enhancing brain-computer interface technology.第二节七选五(共5小题;每小题2.5分,共12.5分)When I graduated from high school,I wanted to major in comparative literature.But,once I found out my fiends were going into“real”majors,like marketing,nursing,and engineering,II forced myself to believe that figured I needed to do the same to ensure a good career. 36 I would enjoy(it and succeed in the future,but eventually I exhausted myself understanding theeconomy and trying new marketing ing out of this experience,I realize it is OK tobe different from others and to study things like classics,art history and other majors offered in the College of Humanities(人文学科)!The worries most people have about a Humanities degree and finding a career afterwards are Actually ideas discussed in Humanities classes,which that the majors are too abstract. 37 are occasionally different from what people commonly believe,offer a broad perspective(视角).How could one effectively be an unbiased(无偏见的)writer with only a knowledge of the popular opinion of society?How could one speak persuasively with closed minds?Only seeing the world through a single perspective leads to missed learning,missed friendships,and missed growth! 38STEM(science,technology,engineering,and mathematics)graduates learn actual skills in their studies,while humanities majors learn "soft skills"like communicating effectively through writing critically and speaking persuasively,synthesizing(综合)ideas through gathering and interpreting information,and developing cultural awareness.Do those soft skills sound useless and inapplicable Produce ideas?Encounter people from other cultures?Every day.to you?Think of it.39 Every SECOND of every day.So why not master these skills?40 The job market is quietly creating thousands of openings a week for people who can bring a humanist's grace to our rapidly evolving high-tech future.Your skills will be valuable to any workplace you hope to be in.Stick to your dream major with all your energy,no matter what other people think.A.So one will not obtain any practical skills.B.How often do you communicate with others?C.How much progress can you make in a certain time?D.So I changed my mind and chose Business Management as my major.E.If you choose a major in the College of Humanities,you will be needed.F.The number of students majoring in the humanities has declined by about half.G.With a broader perspective,we will be more open-minded and less limited in what we can become!第三节完形填空(共15小题,每小题1分,满分15分)In 1980,Foley was a new nurse,working the night shift in a maternity ward(产房).One night,a baby girl was born with a 41 congenital(天生的)disorder that affected her brain.She was 42 to die soon.As Foley had seen in similar cases,babies in this 43 were often placed in a bassinet(摇篮)and received little 44 until they died.But Foley said Nancy Allspach,a colleague of hers,had a 45 approach.“She went into the nursery multiple times through the shift and 46 that baby,”Foley recalled.“She put her 47 right down next to the baby,and she talked to the baby.And she even 48 the baby a bottle and rocked her in the big rocking chair.And she 49 the baby as thoughshe were her own.”Foley 50 remembers how the baby was treated,and how the mother was treated,too.Over her nearly 50-year 51 as a registered nurse,Foley has 52 many babies and children who died later.And looking back,she said she always tied to treat both the children and their parents with compassion(同情)—the way she 53 from Nancy Allspach."I never forgot the importance of touching and being 54 to the baby or the child and also the parents,”she said.“Because,at that moment,what they need is 55 .And Nancy taught me that.'41. A. fancy42. A. encouraged43. A. atmosphere44. A. attention45. A. passive46. A. spoiled47. A. face48. A. showed49. A. noticed50. A. clearly51. A. request52. A. met with53. A. heard54. A. polite55. A. compassionB. severeB. forcedB. pointB. commitment B. differentB. rankedB. footB. boughtB. treatedB. hardlyB. ambitionB. looked atB. learnedB. familiarB. destinationC. mildC. considered C. conceptC. contribution C. fatalC. held C. earC. drankC. defeated C. normally C. planC. cared for C. received C. similarC. exampleD. joyfulD. managed D. condition D. improvement D. broadD. setD. backD. fedD. keptD. carefully D. careerD. picked up D. borrowed D. closeD. competition第Ⅱ卷(非选择题共55分)第一部分语法填空(共10小题,每小题1.5分;共15分)阅读下面短文,在空白处填入1个适当的单词或括号内单词的正确形式(注意:答案请写在答题卡上,写在本卷无效)。
Simulating Ocean Water
2. an understanding of some algorithms that generate/animate water surface height fields suitable for modeling waves as big as storm surges and as small aonstrated by the pioneering efforts in the films Waterworld and Titanic, as well as several other films made since about 1995, images of cg water can be generated with a high degree of realism. However, this level of realism has been mostly limited to relatively calm, nice ocean conditions. Conditions with large amounts of spray, breaking waves, foam, splashing, and wakes are improving and approaching the same realistic look.
高一科学探索英语阅读理解25题
高一科学探索英语阅读理解25题1<背景文章>The Big Bang Theory is one of the most important scientific theories in modern cosmology. It attempts to explain the origin and evolution of the universe. According to the Big Bang theory, the universe began as an extremely hot and dense singularity. Then, a tremendous explosion occurred, releasing an enormous amount of energy and matter. This event marked the beginning of time and space.In the early moments after the Big Bang, the universe was filled with a hot, dense plasma of subatomic particles. As the universe expanded and cooled, these particles began to combine and form atoms. The first atoms to form were hydrogen and helium. Over time, gravity caused these atoms to clump together to form stars and galaxies.The discovery of the cosmic microwave background radiation in 1964 provided strong evidence for the Big Bang theory. This radiation is thought to be the residual heat from the Big Bang and is uniformly distributed throughout the universe.The Big Bang theory has had a profound impact on modern science. It has helped us understand the origin and evolution of the universe, as well as the formation of stars and galaxies. It has also led to the development ofnew technologies, such as telescopes and satellites, that have allowed us to study the universe in greater detail.1. According to the Big Bang theory, the universe began as ___.A. a cold and empty spaceB. an extremely hot and dense singularityC. a collection of stars and galaxiesD. a large cloud of gas and dust答案:B。
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年开始, 位诺贝尔医学奖得主在Springer发表著作 从1906年开始,超过 年开始 超过100位诺贝尔医学奖得主在 位诺贝尔医学奖得主在 发表著作
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电子商务论文参考文献精选3篇
电子商务论文参考文献精选3篇篇一:电子商务毕业论文参考文献电子商务毕业论文参考文献电子商务毕业论文参考文献(一)世纪的典型特征之一是信息经济时代的到来,信息化的浪潮正在深刻影响着全社会的各个方面。
电子商务作为当代信息技术最典型的一个应用,正在彻底地改变着世界和国家的未来,同时,也给了发展中国家一个在经济领域中和发达国家平等竞争的机会。
因此,从政府到企业到个人,全社会的每一个成员都应当为推动电子商务发展、建立健全电子商务支付体系而努力,追随时代发展的脚步,为繁荣国民经济,融入世界经济浪潮献力。
《电子商务教程》胡玫艳主编广州华南理工大学出版社2003年 8月《电子商务概论》李琪主编高等教育出版社2004年9月《中国电子商务发展研究报告》吕廷杰,徐华飞主编北京邮电大学出版社 2003年《电子商务:商业、技术和社会》 (美)劳顿(Laudon,K.C.),(美)特瑞佛(Traver.C.G.)箸,劳帼龄等译高等教育出版社 2004年6月《电子商务导论》司志刚,濮小金主编中国水利水电出版社 2005年《信息法教程》朱庆华,杨坚争主编高等教育出版社 2001年11月电子商务毕业论文参考文献(二)基于电子商务的组织结构内容论文摘要:组织结构设计理论一直是管理学研究的核心内容,优化组织结构尤其是电子商务时代的组织结构,对组织成长和持续提高组织绩效至关重要。
本文在分析现代组织设计的内容、影响组织设计因素的基础上,提出了电子商务时代组织结构设计的发展趋势。
互联网的发展改变了经济发展规律和市场结构,网络的价值与网络节点数的平方成正比,其发展规律是收益递增法则。
电子商务作为网络时代技术发展的必然结果,使企业置身于全球市场,面临着国际竞争。
顾客通过Internet可以搜索到更全面、更完善的产品价格信息,市场权力开始向顾客转移。
在电子商务时代,企业面对的是更加多变的环境、更加激烈的竞争和更加挑剔的顾客,这一切对传统的科层式组织结构形成了冲击和挑战。
算法导论Exercises22.5(转载)
算法导论Exercises22.5(转载)Exercises 22.5 - 导论.英⽂第3版最近看书的同时, 感觉⼀些练习缺少参考, 所以按部分总结了⾃⼰的解答, 也能够强化学习过程.如有不⾜或疑问, 欢迎指正.Exercises 22.5-1How can the number of strongly connected components of a graph change if a newedge is added?可以将每个强连通组件当作⼀个顶点, 组成强连通图, 图内顶点数量即强连通组件数量.如果新增加的边在顶点内部(即指向⾃⼰), 或者重复已有顶点间的边, 则数量没变化.如果新增加的边使图形成环, 这样环内顶点组成⼀个新的强连通组件, 所以数量减少N, N = (环内顶点数量 - 1). Exercises 22.5-2Show how the procedure STRONGLY-CONNECTED-COMPONENTS works on thegraph of Figure 22.6. Specifically, show the finishing times computed in line 1 andthe forest produced in line 3. Assume that the loop of lines 5–7 of DFS considersvertices in alphabetical order and that the adjacency lists are in alphabetical order.按照字母排序的循环和邻接表, 可得出第⼀次DFS访问顶点顺序, 如下(q (s (v (w, w) v) s) (t (x (z, z) x) (y, y) t) q) (r (u, u) r)finishing time: f(r) 20, f(u) 19, r(q) 16, f(t) 15, f(y) 14,f(x) 12, f(z) 11, f(s) 7, f(v) 6, f(w) 5.根据 finishing time 降序排列, 并倒转上图中的边, 第⼆次DFS访问顶点顺序, 如下(r, r) * (u, u) * (q (y (t, t) y) q) * (x (z, z) x) * (s (w (v, v) w) s)每个不相关括号(⽤*间隔)内的顶点, 代表 line 3 ⽣成的树(即强连通组件)ANSWER:DFS(G)森林:(其中红⾊为树边)强连通分量结果:Exercises 22.5-3Professor Bacon claims that the algorithm for strongly connected componentswould be simpler if it used the original (instead of the transpose) graph in thesecond depth-first search and scanned the vertices in order of increasing finishingtimes. Does this simpler algorithm always produce correct results?设想对上图应⽤指定的升序式算法, 图中有A, B, C 三个顶点, A->B, B->A, B->C 三条边.如果⾸次 DFS 从 B 开始, 先向 A 遍历, 则访问顶点顺序为 (B (A, A) (C, C) B)升序排列 finishing time 是 A, C, B. 这样第⼆次进⾏ DFS 则应从 A 开始, 该算法结果显⽰ A, B, C 是⼀个强连通组件, ⽽实际情况不是如此.该算法不能保证通⽤性, 只有在选择特殊顶点作为起始点, 以及规定邻接表顺序的情况下,结果才有可能是正确的.Exercises 22.5-4Prove that for any directed graph G, we have (( GT)SCC)T = (G)SCC. That is, thetranspose of the component graph of GT is the same as the component graph of G.在图 G 中, 同⼀组件中的顶点可以互相连通. ⽽图 GT 中, 组件中的边虽然反转,但其顶点仍可以互相连通, 这⽅⾯是不受影响的, 组件之间的边全部反转, 同样不会形成新的组件. 所以 ((GT)SCC)T = (G)SCC, 即 GT 和 G 的强连通组件相同.Exercises 22.5-5Give an O (V + E)-time algorithm to compute the component graph of a directedgraph G = (V, E). Make sure that there is at most one edge between two verticesin the component graph your algorithm produces.(1) first DFS (G)if v finishorderList.push_front(v) // orderList 是 finishing time 降序队列时间 O(V + E)(2) for each v in Vfor each x in v.adjx.adj.push_back(v)即求 GT 时间 O(V + E)(3) second DFS (GT)for v in order of orderListmap v to scc // scc 是强连通组件for each x in v.adjif x.color = COLOR_BLACK // 代表这条边(v, x)是强连通组件间的边if x non-exist in scc.adj // 在DFS(GT)期间总搜索时间 O(E)scc.adj.push_back(x)即求 scc 和 scc.adj 时间 O(V + E), 所以算法时间复杂度 O(V + E).即:(1)利⽤STRONGLY-CONNECTED-COMPONENTS(G)将结点分类,给每个分量中的结点赋予⼀个相同的标号,时间为O(V+E)。
河北省2024-2025学年高三上学期9月月考英语试题
河北省2024-2025学年高三上学期9月月考英语试题一、听力选择题1.What will the man probably do next?A.Make a cake.B.Take part in a race.C.Stop at the supermarket. 2.What does the man advise the woman to do?A.Take a few risks.B.Watch out for potential dangers.C.Avoid harming the natural system.3.What does the man intend to do?A.Buy a house.B.Expand his house.C.Advertise his house. 4.What are the speakers talking about?A.Drink orders.B.Items on the menu.C.Their favorite fruit. 5.Who is Elle most likely to be?A.Elena’s sister.B.John’s daughter.C.John’s elder sister.听下面一段较长对话,回答以下小题。
6.What do we know about Rob Brown?A.He will graduate next year.B.He takes an interest in cooking.C.He’s dissatisfied with Stacy’s service.7.What problem does Stacy find out?A.Rob clicked the wrong birth date.B.Rob selected the wrong year for his class.C.Rob didn’t know how to register for the course.听下面一段较长对话,回答以下小题。
isserlis' theorem 概率论
isserlis' theorem 概率论
Isserlis定理是概率论中的一个重要定理,它提供了多元高斯随机变量的条件期望的公式。
具体来说,对于多元高斯随机变量X,如果A是X的转置矩阵,那么X的条件期望E(X|A'X)等于X减去X与A'的协方差矩阵的逆矩阵的乘积。
Isserlis定理在统计推断、信号处理、机器学习等领域有着广泛的应用。
例如,在多元线性回归模型中,Isserlis定理可以用于计算回归系数的条件期望和条件方差,从而进行统计推断和模型选择。
此外,在信号处理中,Isserlis定理可以用于计算信号的线性预测系数和条件均值,从而实现信号的降噪和滤波。
英语引用名言的格式
英语引用名言的格式1.英语论文中,引用名人名言的格式是什么一、英语论文中引用名人名言的格式通常分为直接引用和间接引用。
1、直接引用先介绍名人的来历,后面直接引出名人的原话。
例如:According to Francis Bacon, a renowned British writer and philosopher, "Money is a good servant and a bad master."翻译:英国著名作家和哲学家培根(FrancisBacon)说:“金钱是一个好仆人,也是一个坏主人。
”2、间接引用间接引用通常为引用俗语或者古话。
例句:There goes a saying that he knows most who speaks least.翻译:有句俗语说,谁说得最少,谁知道得最多。
二、英语论文中引用一句句子的格式是:As an old saying goes+(引用的句子)。
引述别人的观点,可以直接引用,也可以间接引用。
无论采用何种方式,论文作者必须注明所引文字的作者和出处。
目前美国学术界通行的做法是在引文后以圆括弧形式注明引文作者及出处。
三、正确引用作品原文或专家、学者的论述是写好英语论文的重要环节;既要注意引述与论文的有机统一,即其逻辑性,又要注意引述格式(即英语论文参考文献)的规范性。
扩展资料:命题方式简明扼要,提纲挈领。
英文题名方法①英文题名以短语为主要形式,尤以名词短语最常见,即题名基本上由一个或几个名词加上其前置和(或)后置定语构成;短语型题名要确定好中心词,再进行前后修饰。
各个词的顺序很重要,词序不当,会导致表达不准。
②一般不要用陈述句,因为题名主要起标示作用,而陈述句容易使题名具有判断式的语义,且不够精炼和醒目。
少数情况(评述性、综述性和驳斥性)下可以用疑问句做题名,因为疑问句有探讨性语气,易引起读者兴趣。
③同一篇论文的英文题名与中文题名内容上应一致,但不等于说词语要一一对应。
浅谈心形线
浅谈心形线History of cardioidsThe cardioid, a name first used by de Castillon in a paper in the Philosophical Transactions of the Royal Societyin 1741, is a curve that is the locus of a point on the circumference of circle rolling round the circumference of a circle of equal radius. Of course the name means 'heart-shaped'.Its length had been found by La Hire in 1708, and he therefore has some claim to be the discoverer of the curve. In the notation given above the length is 16a. It is a special case of the Limacon of Pascal (Etienne Pascal) and so, in a sense, its study goes back long before Castillon or La Hire.There are exactly three parallel tangents to the cardioid with any given gradient. Also the tangents at the ends of any chord through the cusp point are at right angles. The length of any chord through the cusp point is 4a and the area of the cardioid is 6πa2.1.摘要:In geometry, a cardioid is the curve traced by a point on the edge of a circular wheel that is rolling around a fixed wheel of the same size. The resulting curve is roughly heart-shaped, with a cusp at the place where the point touches the fixed wheel.The cardioid is a roulette, and can be viewed as either an epicycloid with one cusp or as a member of the family of limaçons. It is also a type of sinusoidal spiral, and is the inverse curve of a parabola with the focus as the center of inversion.3.引言:(1)来历:心形线的外形就像一颗红心,让人不免产生浪漫的联系。
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ag ah ∂rGm ø ø G H ø 因为∑γBμ =ΔrGm 则,( ) , =ΔrGm +RTln (5) b ∂μ T P aa ab
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