Loading...

Table of Content

    20 May 2012 Volume 31 Issue 5
      
    著者文摘
    China undergraduate physics tournament and its enhancement of students' comprehensive ability
    . 2012, 31(5):  1-1. 
    Abstract ( 779 )   PDF (395KB) ( 641 )  
    Related Articles | Metrics
    The establishment of China undergraduate physics tournament(CUPT),task and regulation,and the proceeding of the first CUPT are introduced.The function to enhance the comprehensive ability of undergraduate students is investigated.
    The energy transformation of a row of dominoes gradually increasing in height falling in sequence
    . 2012, 31(5):  5-5. 
    Abstract ( 1046 )   PDF (327KB) ( 752 )  
    Related Articles | Metrics
    A row of "dominoes" gradually increasing in height falling in sequence after the first is displaced,in which the total gravitational potential energy of system decreases and a part of gravity potential energy is transferred into the rotational kinetic energy of next domino.The rotational kinetic energy of falling domino has a certain relationship with the system energy transformation according to the angular momentum theorem.The condition of dominoes falling is determined by space,height of two adjacent dominoes and the angular velocity of next domino.
    Discussion on the appropriate stable suspension condition of levitron
    . 2012, 31(5):  8-8. 
    Abstract ( 1429 )   PDF (276KB) ( 812 )  
    Related Articles | Metrics
    With the help of the stable theory in Newtonian mechanics,the appropriate stable suspension condition of levitron is researched.The space distribution of magnetic field stimulated is measured experimentally by the base of the levitron.The combination between the theoretical analysis and the experimental measurement predict the district of the stable suspension of levitron,which is in agreement with the experimental observation.Then the stable suspension condition is grasped.
    Matrix elements and classical limits of nonlinear oscillator
    . 2012, 31(5):  11-11. 
    Abstract ( 678 )   PDF (337KB) ( 408 )  
    Related Articles | Metrics
    For a nonlinear harmonic oscillator with potential V(x)=1/2mω2x2+λx4,the classical equation of motion can not be solved by the perturbation method.The classical solution of the nonlinear oscillator is derived from quantum matrix elements by using the Heisenberg correspondence principle,which helps us to understand the properties of the nonlinear oscillator more profoundly.
    The electric field intensity of a homogeneously charged circular ring
    . 2012, 31(5):  14-14. 
    Abstract ( 1847 )   PDF (218KB) ( 1376 )  
    Related Articles | Metrics
    The electric fleld intensity of a homogeneously charged circular ring is calculated in the Cartesian coordinates and transformed to the cylindrical and spherical coordinates.
    Simple introduction for Wigner function
    . 2012, 31(5):  17-17. 
    Abstract ( 1003 )   PDF (246KB) ( 765 )  
    Related Articles | Metrics
    By combing the pure Gaussian forms of the completness for the coordinate and momentum representations with the physical meaning of Wigner function,we introduce the Wigner operator and Wigner function under the meaning of the quantum statistics.
    Symmetry and conserved quantity of forced oscillator
    . 2012, 31(5):  19-19. 
    Abstract ( 547 )   PDF (247KB) ( 418 )  
    Related Articles | Metrics
    Symmetry and conservation of a forced oscillation system are studied.The concrete form of time-dependent potential is deduced,and the corresponding symmetric transform operators are also given.Finally,the time-dependent conserved quantity is discussed for linear harmonic oscillation system.
    The symmetric local vibration mode induced by an impurity atom in a diatomic linear chain with on-site potential
    . 2012, 31(5):  21-21. 
    Abstract ( 597 )   PDF (284KB) ( 368 )  
    Related Articles | Metrics
    The lattice vibration equations of a diatomic chain with an impurity atom and on-site potential are solved.The analytic solutions of local vibration are obtained.The basic features of the effect of on-site potential on the local vibration are given,and the existence forms of symmetric localized mode are also discussed.
    Intensive study on four kinds of effusion problems
    . 2012, 31(5):  24-24. 
    Abstract ( 1006 )   PDF (537KB) ( 583 )  
    Related Articles | Metrics
    Four kinds of effusion problems in thermal physics is calculated in detail and the results are discussed.The problems for constant temperature effusion have analytlcal solutions,but the adiabatic effusion problems often have only numerical results due to limited mathematics knowledge.The conditions of quasi-equilibrium state in effusion process are also analyzed generally.They will help teachers and students get entire understanding of the effusion problems.
    Influence of external pressure on saturated vapour pressure
    . 2012, 31(5):  29-29. 
    Abstract ( 1060 )   PDF (265KB) ( 844 )  
    Related Articles | Metrics
    The influence of external pressure on saturated vapour pressure is discussed,and the proof with mechanical equilibrium condition in capillarity and the isothermal barometric formula is given.
    Magnetic field intensity of the separated current-carrying thin cylinders calculated by using magnetic vector potential
    . 2012, 31(5):  32-32. 
    Abstract ( 784 )   PDF (246KB) ( 439 )  
    Related Articles | Metrics
    The magnetic vector potential line between a pair of current straight wire and current-carrying thin cylinders is compared according to the characteristics of magnetic vector potential line.The function of the magnetic vector potential about current-carrying thin cylinders is easily calculated.
    Spin precession of a polaron in one-dimensional organic polymers
    . 2012, 31(5):  35-35. 
    Abstract ( 716 )   PDF (378KB) ( 438 )  
    Related Articles | Metrics
    The spin dynamics of a polaron under a gate voltage in a one-dimensional organic polymer chain is investigated theoretically.Spin precession is obtained when a polaron transports along the polymer chain in virtue of spin-orbital interaction.
    A simplified calculation for deformation and mass distribution of elastomer in gravity field
    . 2012, 31(5):  39-39. 
    Abstract ( 754 )   PDF (256KB) ( 453 )  
    Related Articles | Metrics
    According to elastic coefficient formula of elastomer in series and Hooke's law,the formula of the distance of the same particle relative to elastomer fixation is deduced,a mathematical expression of uneven elastomer deformation is given,and the mass distribution and position of the center of mass of a elastomer are discussed.
    Restudy on the velocity of light spot from the search light
    . 2012, 31(5):  41-41. 
    Abstract ( 658 )   PDF (234KB) ( 213 )  
    Related Articles | Metrics
    Using the "parallel line" model with the limit of velocity of light to explain the phenomenon of light spot movement,we generalize the situation to the limitation,however,it results in some localizations.A new "concentric circles" model is proposed,which is much more accord with the actual condition,and can explain the phenomenon of light spot movement.
    Multi-functional demonstrating instrument of angular momentum theorem
    . 2012, 31(5):  43-43. 
    Abstract ( 698 )   PDF (371KB) ( 686 )  
    Related Articles | Metrics
    A multi-functional demonstrating instrument of angular momentum theorem is intoduced,which is simple in structure and convenient for operating.The instrument demonstrates the related experiments of angular momentum theorem and illustrates the physical laws of the rigid-body fixed-point rotation,which is inspiring.In addition,it has the function of analyzing the experimental phenomenon with the angular momentum theorem in the natural coordinate.
    Design of experiment for measuring sound velocity based on doppler effect
    . 2012, 31(5):  47-47. 
    Abstract ( 1062 )   PDF (392KB) ( 978 )  
    Related Articles | Metrics
    The designing experiment of "measuring sound velocity based on Doppler effect" is introduced.The experiment requires students to understand the principle of measuring sound velocity based on Doppler effect,design a set of experimental device of measuring sound velocity based on Doppler effect using the experiment instrument of air track and the experiment instrument of sound velocity measurement,and measuring sound velocity using this experimental device.
    The study of the refractive index increment on the ultrasonic grating experimentation
    . 2012, 31(5):  50-50. 
    Abstract ( 861 )   PDF (356KB) ( 946 )  
    Related Articles | Metrics
    In order to study the refractive index change of the acoustic-optic effect,the intensity distribution of the diffraction spectrum is analyzed by CCD image disposal based on ultrasonic grating experimentation.The phases delay Δ=1.2855 rad and the refractive index increment Δn=3.014×10-6 are obtained by the comparative numerical calculating value on the ultrasonic frequency 10.27MHz.The relation of the piezoelectricity coupling effciency with ultrasonic frequency is discussed,the most coupling efficiency value and the most refractive index increment are obtained for ultrasonic frequency 10.33MHz.The results show that this content can not only enrich experimentation content but can also grow on comprehend acoustic-optic effect on the ultrasonic grating experimentation.
    Fabrication of two-dimensional photonic crystal by double-beam interference
    . 2012, 31(5):  54-54. 
    Abstract ( 615 )   PDF (380KB) ( 893 )  
    Related Articles | Metrics
    The fabricate photonic crystal on photosensitive material is proposed by double-beam interference.The period of the structure can be controlled by changing the angle between two beams.The one-dimensional grating structure and two-dimensional photonic crystals with square lattice and triangular lattice should be obtained by changing the time of exposure and the angle between the interference fringe of two exposures.
    The visual experiment display in quantum mechanics by MATLAB
    . 2012, 31(5):  58-58. 
    Abstract ( 1857 )   PDF (684KB) ( 1341 )  
    Related Articles | Metrics
    Quantum mechanism is a more Abstract science.In order to display some principles and experimental results in quantum mechanics with a more intuitive way,the MATLAB software is used to build a visual platform for quantum mechanics,which can vividly demonstrate double-slit electron diffraction,quantum tunneling effects,the hydrogen atoms electron cloud and the Stark effect and so on.When the related physical parameters are inputted,the corresponding physical phenomena will display on the platform,which allow the students to obtain a more direct learning experience in study.