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Table of Content

    20 March 2015 Volume 34 Issue 3
      
    著者文摘
    X ray diffraction model of crystal and general derivation of Bragg equation
    . 2015, 34(3):  1-1. 
    Abstract ( 2003 )   PDF (192KB) ( 2486 )  
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    On the basis of the multi-beam plane reflection model,the crystal X-ray diffraction Bragg equation of the single-beam plane reflection model is deduced and the derivation of the more general Bragg equation is given.
    Calculation of the effective mass of cyclotron resonance electron on ellipsoidal energy surface
    . 2015, 34(3):  3-3. 
    Abstract ( 914 )   PDF (279KB) ( 662 )  
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    The effective mass of cyclotron resonance electron on the ellipsoidal energy surface is calculated.The effective mass of cyclotron electron is irrelative with selections which are perpendicular to the applied magnetic field.For fixed direction of magnetic field,the effective mass of cyclotron resonance electron on the energy surface is consistent.
    A theorem and application for moment of inertia of a particle system about its centroid-through axis
    . 2015, 34(3):  6-6. 
    Abstract ( 1765 )   PDF (333KB) ( 644 )  
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    The moment of inertia of a plane mass particles system about its centroid-through-axis can be expressed as follows: computing the square of distance of two arbitrary particles,then multiplying it with the two masses,respectively,all of such obtained product sum dividing the mass of the system.It is not needed to determine the centroid of the system but the lengths of lines connecting the two arbitrary particles is needed.Several applications in both rod and plate systems are presented.The examples also include the mixed structure of rod and plate,fractal plate and so on.The proposed expression has both important theoretical and practical value.
    Comparison of different conventions of Poincare algebra
    . 2015, 34(3):  10-10. 
    Abstract ( 732 )   PDF (399KB) ( 860 )  
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    As for the form of the Poincare algebra,there are three different conventions used commonly by mathematicians and physicists.By using two simple methods,we present the derivation of the Poincare algebra in these conventions.We point out several differences due to the choice of the conventions.
    Application of the mirror method based on conformal mapping
    . 2015, 34(3):  14-14. 
    Abstract ( 934 )   PDF (997KB) ( 721 )  
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    Two-dimensional boundary value problem of the complex shape boundary is solved by combing the mirror method with conformal mapping method,and thus the distribution of electric field is got.The electric field line and equipotential line maps are plotted by using mathematical software Matlab,the validity of the method is presented.The application range for mirror method is expanded; a novel idea and way is provided for solving the complex shape boundary in two-dimensional boundary value problem.
    Calculation of the electric field between two confocal elliptic cylindrical plates
    . 2015, 34(3):  17-17. 
    Abstract ( 662 )   PDF (156KB) ( 430 )  
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    According to the equation of the equal potential lines,the distribution of electric field between two confocal elliptic cylindrical plates is calculated by using nature of analytical function.
    Research for two-dimensional standing waves on circular plate
    . 2015, 34(3):  19-19. 
    Abstract ( 1324 )   PDF (1222KB) ( 1511 )  
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    The analytical solution of Chladni figures on a thin mental board is a hard nut to crack in theoretical acoustics.When the boundary of a board is clamped or simply supported,the question can be solved quite completely,but in the condition of free boundary,the solution becomes rather difficult.In this paper,the two-dimensional standing waves of a circular plate( Chladni figures) in various frequencies are investigated experimentally and theoretically.It is found that the Chladni figures can be precisely controlled by adjusting the frequency and position of the vibration source.The patterns of three kinds have been observed,only having circular nodal lines,radial nodal lines and the combination of the two kinds of nodal lines,respectively.Furthermore,the wave vectors,phase velocities and the elastic modulus of the plate are also obtained.The results of experiments well correspond with the analytical solutions.
    Analysis on the figure distortion of hysteresis loops in experiment
    . 2015, 34(3):  25-25. 
    Abstract ( 1690 )   PDF (311KB) ( 677 )  
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    The hysteresis loops are fitted with the cubic polynomial functions as well as Hm,Bm,Hcand Brexpressed by the fitting parameters.In addition,the intensity of the currents in excitation coil and detection coil are calculated based on which the figure distortion of hysteresis loops measured in actual experiments is explained.
    The computer measurement system of magnetostrictive coefficient based on displacement censor
    . 2015, 34(3):  29-29. 
    Abstract ( 655 )   PDF (1102KB) ( 486 )  
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    The high sensitive displacement censor by connecting varistors to be unbalanced bridge,can convert the micro displacement quantity into electricity quantity.It is collected and screened synchronously on the computer by the STM32 micro controller,and the measurement is made to be real-time monitoring.It has practical and convenient merits of easy sample replacement,fast operation and high accurate results.
    Improvement on the demonstration experiment of Rayleigh scattering
    . 2015, 34(3):  33-33. 
    Abstract ( 964 )   PDF (1032KB) ( 943 )  
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    The main component of protein glass is silicon dioxide,which contains a lot of nano-size bubbles of irregular distribution,and its size is much smaller than the wavelength of visible light.Protein glass is used as a scattering medium in order to improve the existing demonstration experiments of Rayleigh scattering,which can demonstrate the influence of medium thickness changes on the scattered light and transmitted light,and polarization characteristics of the scattered light are analyzed.The equipment is uncomplicated and simple to operate,and the phenomena are well observed.
    The good feeling of Wiener to Gottingen University and the evalution between Wiener and Born
    . 2015, 34(3):  36-36. 
    Abstract ( 635 )   PDF (1185KB) ( 601 )  
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    Norbert Wiener was a famous mathematicians in 20 thcentury,and the founder of Cybemetics.Gottingen University gave a huge influence on Wiener in his academic life.Max Born was one of the greatest physicists of the twentieth century.Wiener had a period experience worked together with Max Born,what they did seemed proudly to Wiener,but pity-filled to Born.Wiener always gave high valuation to Max Born,but the evaluation which Born gave to Wiener,as Born said himself,was prejudiced,not much objective.
    A new experimental apparatus of Hall element physical property
    . 2015, 34(3):  41-41. 
    Abstract ( 766 )   PDF (1103KB) ( 437 )  
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    This paper designs and produces a new experimental apparatus,through combining tests of characteristics of linear and switching Hall element,to obtain the threshold value of magnetic induction and the hysteresis curve of switch Hall element.This experimental apparatus can help students deepen their understanding of the physical properties of Hall element.
    Investigation on the forced vibration characteristics of non-contact elastic swing based on RLC resonant circuit
    . 2015, 34(3):  46-46. 
    Abstract ( 828 )   PDF (362KB) ( 554 )  
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    The experiment driving the elastic swing to forced vibration by the electromagnetic vibration,and manipulating the phenomenon that small changes in capacitance value can produce a greater voltage drop on resistance in the RLC resonant circuit value( small changes in the appropriate frequency range),linking the elastic swing with the capacitance characteristics.Then we can get the relationship between the voltage changes and the change of elastic pendulum movement indirectly,and change the excitation frequency to study the amplitude frequency characteristic and phase frequency characteristic of the forced vibration.
    Study on extinguishment and related phenomena of a burning candle in a inverted vessel over water
    . 2015, 34(3):  50-50. 
    Abstract ( 1221 )   PDF (589KB) ( 1287 )  
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    When a measuring cylinder is covered on a burning candle stand up into the water within a beak,extinguishing of the candle and rinsing up of the water in the cylinder are observed simultaneously.The volume of the water that enters into the inverted cylinder is about 20 percent of the volume of the original gas in it.We analyze the effects of physical and chemical contributed factors on the extinguishment of the candle and rising up of the water theoretically.The ratio of water volume entered into the inverted cylinder to the original gas volume in it contributed by chemical factors is about 3.2% to 7.16%.We attributed the ring up of the water in the cylinder to the contribution of physical factors.The heat from combustion of the candle leads to spilling of the gas out of the inverted cylinder,and pressure differences inside and outside the cylinder would be established after the candle extinguishes due to the lowering of the gas temperature.We set up experiments and measured the ratio of water volume entered into the cylinder after the candle extinguishing to the gas volume in the cylinder considering the contribution of physical and chemical factors respectively.The ratio contributed by the physical factors is from 10.65% to 12.98%,while the ratio contributed by the chemical factors is less than 2%.The rising of the water in the inverted cylinder is contributed by the physical factors.
    High frequency electrical wire electromagnetic induction and experimental study of skin effect series
    . 2015, 34(3):  56-56. 
    Abstract ( 930 )   PDF (394KB) ( 1174 )  
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    A set of electromagnetic induction and skin effect experiments on the electrical wire are designed,which can be used to observe the phenomenon of common mode interference of electrified wire and coaxial cable.The high frequency electromagnetic induction apparatus of current carrying conductor skin effect is observed by self-made high frequency comprehensive experimental instrument,and a series resonance is used to measure the increase of good conductor loss resistance with increasing frequency,which is induced by the skin effect.It can be further confirmed that the electromagnetic induction phenomenon can give rise to the skin effect.Meanwhile,we also verify the energy radio transmission of electromagnetic induction,the series of experiments mentioned above should give us better understanding of the principle and effect of electromagnetic induction.
    A rigorous derivation of the Boltzmann distribution
    . 2015, 34(3):  60-60. 
    Abstract ( 1717 )   PDF (531KB) ( 1039 )  
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    Based on high-precision Stirling's formula,we present a new form of Boltzmann distribution as well as its rigorous derivation,utilizing Taylor's theorem for multivariate functions and Lambert W function.Also,this method can be applied for rigorous derivation of Bose distribution and Dirac distribution.