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Table of Content

    20 November 2012 Volume 31 Issue 11
      
    著者文摘
    Applying transformation formula to the integrals of periodic integrand
    . 2012, 31(11):  1-1. 
    Abstract ( 940 )   PDF (312KB) ( 427 )  
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    A formula applying to the integrals of periodic integrand is deduced by inspiring the evaluation of a specific integral.This formula,as well as its equivalent form,provides us a new trick of evaluation of integrals by transforming the integral of a periodic integrand to that with one limit at infinity,or in converse way.
    Surface shape of rotating liquid
    . 2012, 31(11):  5-5. 
    Abstract ( 908 )   PDF (261KB) ( 1444 )  
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    Analyzing rotational motion of a viscous fluid,we find that the surface shape of the rotating liquid depends on how the liquid is rotated.If the liquid is rotated by the outer boundary,its surface appears the shape of paraboloid of revolution;if the liquid is rotated from its center,the surface appears whirlpool shape.
    Discussion on group velocity in anisotropic media
    . 2012, 31(11):  7-7. 
    Abstract ( 874 )   PDF (163KB) ( 476 )  
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    We have derived the dispersion relation of anisotropic media based on Maxwell equations,and the analytic expressions of group velocity for ordinary and extraordinary waves are obtained in a uniaxial anisotropic media.
    Orbits of a particle exerted by attractive force following inverse quintic law
    . 2012, 31(11):  9-9. 
    Abstract ( 932 )   PDF (171KB) ( 544 )  
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    Using hyperbolic function expansion method,we solve a kind of orbital differential equation of a particle exerted by attractive force following the inverse quintic law,and obtain two orbits which describe satellite movement under the action of attractive force following the inverse quintic law.
    Study of energy in wave superposition of two simple harmonic waves in opposite direction
    . 2012, 31(11):  11-11. 
    Abstract ( 815 )   PDF (269KB) ( 614 )  
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    The energy of two simple harmonic waves in opposite direction in superposition process is analyzed theoretically,and the result is that the energy of superposition wave is equal to the sum of two simple harmonic wave energies,and the energy is transferred in different forms at same position.
    Research on separation and eccentric cylindrical surface electrostatic field
    . 2012, 31(11):  14-14. 
    Abstract ( 656 )   PDF (249KB) ( 373 )  
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    In the bipolar cylindrical coordinates,we use the Gauss theorem of electrostatic field to calculate the electric field strength,electric potential and capacitance of separation and eccentric cylindrical surface.
    D'Alembert's equations and antenna radiation
    . 2012, 31(11):  16-16. 
    Abstract ( 746 )   PDF (280KB) ( 433 )  
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    The radiation field of electric dipole the far field radiation power of non-directional antenna and relationship between power and dimension secondly are presented.Two half wave antennas with different dimensions are compared based on Ansoft HFSS,S11 of return loss and far field pattern are changed with frequency or wavelength,the relationship between radiation and antenna operating frequency or wavelength are tested further.Practices show that these perceptual knowledge enhance the quality of teaching and obtain satisfied teaching effects partly.
    Study on equivalent resistance between any nodes of n step network
    . 2012, 31(11):  18-18. 
    Abstract ( 765 )   PDF (415KB) ( 515 )  
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    The equivalent resistance between any nodes of n step network is studied through analysis of network.A model of matrix transform is constructed and a constraint equation on the basis of boundary condition is established.Meanwhile,we work out a fundamental formula of equivalent resistance between any nodes of n step network,and compare different situations of the formula with other conclusions.
    The SO_3 group algebraic approach of n-dimensional hydrogen atom
    . 2012, 31(11):  23-23. 
    Abstract ( 797 )   PDF (160KB) ( 495 )  
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    The n degrees of freedom similar is made as three degrees of freedom by affine.With the help of Laplace-Runge-Lenz vector,we use the SO3 group Lie algebra to calculate n-dimensional hydrogen atom's energy level and degeneracy.
    Test of Newtonian inverse-square law with a torsion pendulum
    . 2012, 31(11):  25-25. 
    Abstract ( 743 )   PDF (424KB) ( 508 )  
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    A number of theoretical speculations predict that the gravitational interaction could display fundamentally new behavior in short-range regime.This paper presented the experimental principle for test of gravitational inverse-square-law,and reported our experiment result on test of gravitational inverse-square-law with a torsion pendulum,as well as the thermal noise and sensitivity analysis.
    Design method of Chebyshev transformer
    . 2012, 31(11):  29-29. 
    Abstract ( 1438 )   PDF (284KB) ( 1084 )  
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    The Chebyshev transformer is a widely used matching component in microwave engineering.However,in several existing textbooks there are some unclear or inaccurate description on design methods of Chebyshev transformer.In this paper,the issues are analyzed,and the design procedure of Chebyshev transformer is discussed based on two different design strategies.
    Measurement of speed for β ray in the air by using plastic scintillator detector
    . 2012, 31(11):  32-32. 
    Abstract ( 745 )   PDF (385KB) ( 329 )  
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    The speed of β-ray in the air is measured by the coincidence of two plastic scintillator detectors using 90Sr-90Y β source.A comparison between theoretical value and the experimental value revised by Casino software considering energy loss is presented.It is shown that the two values are in agreement with each other well.The result provides an experimental evidence for theoretical values of β-ray speed,and it is proved that our equipment and experimental design are effective.
    The research of transmutation of nuclear artificially by Cockroft and Walton
    . 2012, 31(11):  36-36. 
    Abstract ( 1196 )   PDF (851KB) ( 448 )  
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    The biographies of Cockcroft and Walton are outlined.How Cockcroft drew inspiration from Gamow's theory an d submitted his plan of construct a high-voltage accelerator is reviewed.How th ey surmounted difficulties and accomplished the experiment of transmutation of n uclear by artificial means is recounted.The important factors which made them success such as they could seize the opportunity,cooperate in harmony wit h each other,work diligently and be undaunted by repeated setbacks are analyzed.
    Calculation of ellipsoid eddy-current moment under varying magnetic field
    . 2012, 31(11):  43-43. 
    Abstract ( 917 )   PDF (336KB) ( 520 )  
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    The calculation formula of ellipsoid eddy-current and eddy-current moment under varying magnetic field are derived.It is known from the formula that the moment is proportional to the derivative of the magnetic field with time.The coefficient is a constant related to the ellipsoid's shape,size,and material.Then it can be used to calculate the eddy-current fields in the space by the moment.
    Research on ethanol-aqueous solution's irregular acoustic nature
    . 2012, 31(11):  47-47. 
    Abstract ( 848 )   PDF (302KB) ( 999 )  
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    The sound velocity in the ethanol water has the typical features,that is,the relationship between the velocity and the concentration appears such trend which is rising first and declining then,obviously it has an extremum.This article makes explanations in a microscopic view,eventually gives the inference that in the low concentration and the high concentration ethanol-aqueous solution emerge respectively two different rigid clusters with chain structure and planar structure under the effect of hydrogen bond.Due to its different stability,they cause different impacts to the bulk modulus,which then lead to the different regularities of the sound velocity in different concentrations.
    Research on stability of circular orbit of a particle exerted by a central force in a rotating frame of reference
    . 2012, 31(11):  49-49. 
    Abstract ( 785 )   PDF (251KB) ( 337 )  
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    The condition sufficed by a particle,which is engaged in a stable circular orbit as it feels a central force,is analyzed in a rotating frame of reference.
    Dalgarno-Lewis approach of quantum perturbation and its application
    . 2012, 31(11):  52-52. 
    Abstract ( 823 )   PDF (361KB) ( 494 )  
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    Dalgarno-Lewis approach is an elegant perturbation method which provides exact correction terms to a given order and it avoies the difficulties of summing up infinite terms in the ordinary perturbation approaches.We expound Dalgarno-Lewis method and apply it to the problems of energy levels and wave functions of an atom in a semi-space with a coulomb potential and an external weak electric field.The energy levels up to third order and wave functions to first order are calculated.The results are concise and regular in forms,which show the advantages of the Dalgarno-Lewis perturbation method.
    Simulating the Foucault pendulum by movement of the charged pendulum ball in magnetic field
    . 2012, 31(11):  55-55. 
    Abstract ( 1009 )   PDF (360KB) ( 766 )  
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    In the Foucault pendulum experiment,a heavier pendulum and a longer cycloid are used to ensure that the spin of its swing plane can be watched,because the period of the spin of the swing plane caused by the Coriolis force is far more than the swing period of the pendulum.In the laboratory,a magnetic field can be introduced to give the charged pendulum a Lorentz force which can cause the spin of the swing plane.The period of the spin of the swing plane caused by the Lorentz force is not far more than the swing period of the pendulum.Therefore,a short charged pendulum can be used to simulate the movement of the Foucault pendulum for a short time in the laboratory.The paper begins with theoretical analysis,then,uses MATLAB to simulate the movement of the charged pendulum to account for why it is possible to use the movement of a short charged pendulum in a magnetic field to simulate the Foucault pendulum.
    Measurement of the horizontal component of the earth magnetic field by rotating coordinate method
    . 2012, 31(11):  59-59. 
    Abstract ( 930 )   PDF (272KB) ( 345 )  
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    The earth magnetic field is a small vector.A system including two sensors of Hall-effect is build to measure the horizontal component of the earth magnetic field using the rotating coordinate method.In addition,it deduces theoretical result with matrix calculation which correspondes to experiment.The result of measurement of Qingdao is 3.16×10-5 T and the relative error is 0.3%.