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Table of Content

    20 February 2019 Volume 38 Issue 2
      
    Tools made of light———An introduction to the 2018 Nobel Prize in physics
    WANG Ruo-peng
    College Physics. 2019, 38(2):  1-4.  doi:10.16854 /j.cnki.1000-0712.180614
    Abstract ( 1669 )   PDF (702KB) ( 923 )  
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    The Royal Swedish Academy of Sciences awarded the 2018 Nobel Prize in physics to Arthur

    Ashkin,Gérard Mourou and Donna Strickland,“for groundbreaking inventions in the field of laser physics”. This

    article gives a brief introduction to their Nobel Prize-winning inventions.

    Applications of effective-theory method in classical mechanics
    ZHANG Xiao-bing
    College Physics. 2019, 38(2):  5-8.  doi:10.16854 /j.cnki.1000-0712.180285
    Abstract ( 1645 )   PDF (183KB) ( 620 )  
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    By using the effective-theory method,the free-fall problem,the micro-amplitude vibration and

    the particle motion in central potential field are investigated respectively.Based on the manifest symmetry that each

    of problem possesses,part of degrees of freedom are decoupled from the full theory and thus the corresponding

    effective Lagrangians and effective Hamiltonians are derived.These examples slow the superiority of effective-theory

    method in studying classical mechanics.

    Single Fourier transform method for the Fresnel diffraction integration
    CUI Wen-le, HAN Li-qi, HUO Xiao-min, YANG Li-jun, ZHANG Su-heng
    College Physics. 2019, 38(2):  9-16.  doi:10.16854 /j.cnki.1000-0712.180362
    Abstract ( 2705 )   PDF (1121KB) ( 2225 )  
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    The single Fourier transform method is a common approach for numerical calculating the Fresnel

    diffraction integration. In the single Fourier transform method,the sampling of quadratic phase factor and the size of

    the calculation window can seriously affect the calculation accuracy. Based on the concept of local spatial frequency

    and the sampling theorem,this paper gives the ideal sampling interval of quadratic phase factor and the selection

    method of the size of the calculation window. Then the numerical simulation results are compared with the

    theoretical analytical solutions and experimental results,respectively,to verify the effectiveness of the ideal

    sampling interval and the selection method of the size of the calculation window.

    Planet precession and light deflection in general relativity and Brans-Dicke's theory of gravitation
    GAO Xiao-jun, YANG Jin-song
    College Physics. 2019, 38(2):  17-24.  doi:10.16854 /j.cnki.1000-0712.180302.
    Abstract ( 1631 )   PDF (507KB) ( 627 )  
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    As two important alternative theories of gravitation,general relativity and Brans-Dicke's theory,

    play important roles in our understanding the formation and evolution of celestial bodies and cosmology. In this

    paper,we study the planet precession and light deflection in general relativity and Brans-Dicke's theory. Firstly,

    we derive the general orbital equation for a free particle moving in the static,spherically symmetric spacetime by a

    spherical star. Then,we write down the corresponding equations,which are nonlinear ordinary differential equations

      of motion for the planet and light ray by using the spherically symmetric solutions to these vacuum field equations in

      these two theories. Finally,the approximation solutions to the equations of motion can be obtained by the

      perturbation method,which yield the angles corresponding to the planet precession and light deflection. These

      results presented in this paper will help us to check and distinguish these two theories of gravity using high -

      precision experimental observation.

    Deriving Einstein’s superposition formula of velocity by methods of analogue
    ZHOU Guo-quan
    College Physics. 2019, 38(2):  25-27.  doi:10.16854 /j.cnki.1000-0712.180416
    Abstract ( 3210 )   PDF (241KB) ( 1448 )  
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    The most simple case in the special relativity is taken as a reference in this paper,the restricted

    Lorentz transformation is rewritten in a four -dimensional transformation form. The property of four - dimensional

    Mink space is demonstrated and analyzed,the rotational meaning in the four-dimensional Mink space is also thrown

    light up. The methods of analogue are used to derive Einstein’s superposition formula of velocity.

    Topological charge measurement of vortex beams based on prism interferometry
    FANG Liang, JU Pei, GAN Xue-tao, ZHAO Jian-lin
    College Physics. 2019, 38(2):  28-32.  doi:10.16854 /j.cnki.1000-0712.180139
    Abstract ( 1905 )   PDF (873KB) ( 1228 )  
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    The self - interference phenomenon of a vortex beam passing through a single splitting prism is

    analyzed theoretically and studied experimentally. The results show that the self-interference fringes of the vortex

    beams are twisted,which are different from the interference of a vortex beam with a plane or spherical wave. At the

    edge of the interference fringes,the number of fracture stripes will increase with the increase of the vortex

      topological charge,and the direction of the fracture stripe is determined by the symbol of topological charge. The

      above conclusion provides a new method for measuring the topological charges of vortex beams in a simple way.

    A graphic analysis of Millikan oil drop experiment design details
    TANG Xiao, ZHOU Xian-ju, LI Deng-feng, XIANG Guo-tao,
    College Physics. 2019, 38(2):  33-36.  doi:10.16854 /j.cnki.1000-0712.180348
    Abstract ( 4717 )   PDF (495KB) ( 1087 )  
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    The Milligan oil droplet experiment has many influencing factors and the relationship between them

    is complex,which leads to students' difficulty in understanding its experimental mechanism. The graphic analysis in

    detail of Millikan oil drop experiment design helps to solve this problem. The experimental design idea as a main

    story line,kinematics of oil droplets and relationship between experimental parameters are analyzed.

    The early research on nuclear magnetic resonance by Felix Bloch
    YIN Xiao-dong, WANG Xin-yan, LIU Zhan-cun, WANG Fu-he
    College Physics. 2019, 38(2):  37-44.  doi:10.16854 /j.cnki.1000-0712.180336
    Abstract ( 1634 )   PDF (376KB) ( 737 )  
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    The biography of Felix Bloch is sketched. His innovation experience of measuring the neutron

    magnetic moment,and then realizing nuclear magnetic resonance in condensed matter,and early research on NMR

    is reviewed. How he acquired inspiration from contemplate deeply,shrank from toil and hardship,paid attention to

    multi-discipline integration is analyzed.

    Austrian physicist Anton Zeilinger and quantum information
    YIN Pei, ZHU Hui-juan
    College Physics. 2019, 38(2):  45-51.  doi:10.16854 /j.cnki.1000-0712.180338
    Abstract ( 3290 )   PDF (254KB) ( 768 )  
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    Quantum information science is currently a major global hotspot,including quantum communications

    and quantum computing. Quantum entanglement,the special character of quantum mechanics,is the basis of

    quantum information,and quantum teleportation is one important option to realize quantum communication.

    Austrian physicist Anton Zeilinger is an indispensable figure in this research. This paper introduces Zeilinger's

      research experience and his role in the verification of Bell's inequality to the development of quantum information,

      including multi-particle entanglement and quantum teleportation. At the same time,we analyze some researchers

      that have great influence on his research.

    Application of electromagnetic Doppler effect in upper atmosphere detection
    ZHANG Chun-min
    College Physics. 2019, 38(2):  52-54.  doi:10.16854 /j.cnki.1000-0712.180297
    Abstract ( 1779 )   PDF (502KB) ( 618 )  
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    Wind is a key parameter for understanding the behavior of atmospheric dynamics,thermodynamic

    properties and compositional structure. The detection of atmospheric wind field has become the frontier science and

    popular research topic in the world now. The basic theory for the passive detection of wind fields in the upper

    atmosphere ( 80~300km) is the interference imaging technique and the Doppler effect of electromagnetic waves. The

    paper explains the formation of airglow ( aurora) ,the Doppler effect of electromagnetic waves,and the two-beam

    interference. The principle of the speed of the atmospheric wind field,temperature and particle radiation are known

      by detecting the Doppler shift of the target air glow spectrum is discussed. The four -intensity detection theory is

      presented,in which the observation of frequency shift is converted into phase and interferogram observation because

      frequency shift is difficult to observe for its small value. It is shown that the ingenuity and perfection of the application

      of the fundamental principles of electromagnetism and optics in today's high - technology,which will inspire the

      application of basic knowledge of physics and the association of the innovative thinking of scientists.

    Electric dipoles and collision-induced absorption spectra in cool   star atmospheres
    WANG Fei
    College Physics. 2019, 38(2):  55-59.  doi:10.16854 /j.cnki.10000712.180361
    Abstract ( 1575 )   PDF (542KB) ( 629 )  
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    Electric dipoles are generated not only from the displacement polarization of nonpolar molecule and

    the turning direction polarization of polar molecule but also from the collisions between atoms and molecules in

    dense gas.The infrared photon is absorbed by molecule pairs formed in dense atmospheres of“cool”star and outer

    planet due to the interactions between collision-induced dipole moments and electromagnetic radiation.The collision

      -induced absorption spectra are also introduced for hydrogen dense gas in white dwarfs atmospheres.

    Exploration and practice of two credits "statistical thermodynamics" course
    CUI Xin, BAN Shi-liang, GONG Jian, LIANG Xi-xia
    College Physics. 2019, 38(2):  60-62.  doi:10.16854/j.cnki.1000-0712.180369
    Abstract ( 1348 )   PDF (131KB) ( 537 )  
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    In this paper, the design of teaching scheme and teaching practice about " statistical thermodynamics"

    ( thermodynamics and statistical physics) course for students of applied physics and electronic science and technology

    in Inner Mongolia university are introduced.Overall consideration of several aspects about basic theory,method and application

    can be done in 32 credit hours, and the knowledge systematicness and integrity of thermodynamics and statistical

    physics course can be ensured.

    Optical field modulation phase imaging technology and teaching application combined with public multimedia
    DUAN Yi-tong, ZHU Jia-xiao, WU Jian
    College Physics. 2019, 38(2):  63-66.  doi:10.16854/j.cnki.1000-0712.180233
    Abstract ( 1353 )   PDF (1514KB) ( 428 )  
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    An optical field modulation phase imaging experimental teaching system using public multimedia is

    developed.The system is composed of auxiliary lighting and image recording.The auxiliary lighting part can be implemented

    by the classroom's public multimedia projector.The teaching system can be used to live demonstrations in

    the classroom directly.The system uses two different phase demodulation algorithms———four-step phase -shifting

      and Fourier spectrum analysis methods to realize numerical reconstruction of three-dimensional image,and a software

      operation interface is written for the two algorithms.The software demonstrates the algorithm process and explained

      the principle,which makes it easier for students to understand the principle of optical field modulation phase

      imaging.