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Table of Content

    20 August 2016 Volume 35 Issue 8
      
    Spacetime Symmetries and Conservation Laws ( Ⅱ)———Classical Electrodynamics
    ZHAO Kai-hua
    College Physics. 2016, 35(8):  1-13. 
    Abstract ( 1051 )   PDF (994KB) ( 1061 )  
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    The conservation laws of energy,momentum and angular momentun in classical electrodynamics are derived from the translational and rotational spacetime symmetries
    A fundamental theorem in time-dependent quantum theory and its application to analysis of non-periodical terms
    CHEN Bing-jin,LIU Quan-hui
    College Physics. 2016, 35(8):  14-17. 
    Abstract ( 827 )   PDF (339KB) ( 512 )  
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    Textbooks on quantum mechanics usually assert that perturbation theory holds true only for sufficient short time. This mistake results from direct contribution of the non-periodical time term into probabilities. We first introduce a fundamental theorem in the time-dependent quantum theory,then point out that the non-periodical time terms are in fact perturbation expansions of time-dependent phase factor.
    Revisit on the dimension analysis to calculate the moment of inertia of fractal body
    FANG Wei,TU Hong,FENG Jie
    College Physics. 2016, 35(8):  18-21. 
    Abstract ( 908 )   PDF (830KB) ( 856 )  
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    The difference between ideal infinite-order fractal in mathematical sense and real finite-order fractal in physical sense is distinguished. Using scale transformation and dimension analysis,the recurrence formula for the moment of inertia of n-order fractal triangle is obtained,which leads to the final expression for the moment of inertia When n tends to infinity,the result of this expression is in accordance with infinite-order fractal objects.
    Analysis of beetle and ring problem
    LI Li,ZHANG Yin
    College Physics. 2016, 35(8):  22-24. 
    Abstract ( 1332 )   PDF (852KB) ( 1135 )  
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     The“beetle and ring problem”is analyzed tersely and intuitively by mass-point set mechanics. The equations of beetle and marked point’s track are solved. Then the movement trajectories with different quality ratio are plotted and trajectory of latter is hypocycloid.
    The connections between optical and mechanical problems: by talking about catenary and mirage
    ZHAO Hu,WANG Qi
    College Physics. 2016, 35(8):  25-28. 
    Abstract ( 850 )   PDF (552KB) ( 901 )  
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    The mathematical model and conventional solution of catenary and mirage are briefly introduced at first. Then, the catenary equation is discussed in terms of Snell’s Law, and the forming of a mirage is described on the basis of Lagrangian. Based on the analysis of the relations between these two mathematical models, the value of the connections between Hamilton’s principle and Fermat’s principle is re-emphasized for the physics education at university.
    Calculation of the interaction of the two coaxial charged rings
    YANG Tian-hu
    College Physics. 2016, 35(8):  29-31. 
    Abstract ( 968 )   PDF (664KB) ( 540 )  
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    The series solution of the two coaxial charged rings is derived,whose convergence and terror are quantitatively analyzed. According to the series solution,the distribution curve of the interaction Fz is calculated and drawn by the MATLAB programming.
    The characteristic analysis of the diffraction pattern of two-dimensional grating
    YU Feng-jun
    College Physics. 2016, 35(8):  32-35. 
    Abstract ( 2460 )   PDF (807KB) ( 2014 )  
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    The position formula for the diffractive light-spot of two-dimensional grating is derived. The property of diffraction pattern is discussed and its experimental demonstration is given. A new method of measurement of grating constant is presented.
    Calculation of ground state energy of the helium atom by parameter perturbation method
    LU Ji,LI Tian-le,XI Wei,ZHANG Chang-xin
    College Physics. 2016, 35(8):  36-38. 
    Abstract ( 1311 )   PDF (341KB) ( 608 )  
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    According to the parameter perturbation theory,a combination of the ns wave functions of two hydrogen-like atoms with effective nuclear charge number of Z* = 2-σ is chosen to be the first order approximation and the fourth order approximation of wave function for the ground state of helium atom. The fourth level approximate energy of the ground state of helium atom is calculated by using the application of perturbation method. The calculation results show that the error of the fourth level approximation energy of helium atomic ground state by the parameter perturbation method is ΔE= 0.004922028*es2/a0 comparing with the experiment result.
    Solution of one-dimensional finite symmetric square potential well model using the basis expansion method
    WANG Zai-jun
    College Physics. 2016, 35(8):  39-43. 
    Abstract ( 1253 )   PDF (554KB) ( 2018 )  
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    The one - dimensional finite symmetric square potential well model is studied by using the basis expansion method. The results are in agreement well with those obtained ones by solving the Schrdinger equation in the coordinate representation. The calculation is a good illustration of the basis expansion method in the quantum mechanics and provides a good example for teaching and studying of the method. In addition,numerical evaluation of the results also provides a good reference for teaching and studying of solving quantum problems by using computers.
    The measurement and application of the birefringence effect in liquid crystal cell
    LIAO Hong-bo,WANG Ting,HE Chen-juan,WANG Hai-yan
    College Physics. 2016, 35(8):  44-47. 
    Abstract ( 1295 )   PDF (860KB) ( 1549 )  
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    An experimental method of measuring the birefringence effect in liquid crystal cell is introduced. By using such a method,the anchoring direction and the twist angle of the liquid crystal cell can be basically determined. The possibility of using this method to calibrate the polarized direction of a polaroid is also discussed.
    Construction and practice of the innovative and practical educational platform for optical experiments
    ZHENG Hong,SUN La-zhen,ZHANG Zeng-ming,ZHU Ling,WANG Zhong-ping,ZHANG Quan
    College Physics. 2016, 35(8):  48-51. 
    Abstract ( 830 )   PDF (1487KB) ( 899 )  
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    Combined with the innovation of physics experimental teaching in Physics Experiment Teaching Center of University of Science and Technology of China,with teaching of optics experiments for college physics as an example,we introduce the construction and practice of optical innovative and practical educational platform for multiple levels of college physics experiment curriculum system; then,how to play the special skill and advantages of physical experimental teaching in colleges and universities for training of bright people with creative mind; construction and practice serve to the training and cultivation of basic scientific accomplishments and the capability for scientific research for students.
    Research on effectiveness of blended learning with SPOC model in university physics
    ZHANG Rui,WANG Zu-yuan,XU Xiao-feng
    College Physics. 2016, 35(8):  52-54. 
    Abstract ( 939 )   PDF (824KB) ( 514 )  
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    Teaching of university physics in the SPOC model is studied through cluster analysis and comparative analysis.The results show that the improvement in blended learning is mostly due to the increase in effective learning time.
    Research on YPT evaluation model and cultivating students’creative thinking based on IYPT
    ZHANG Yi-chi,LU Jian-long
    College Physics. 2016, 35(8):  55-60. 
    Abstract ( 935 )   PDF (682KB) ( 433 )  
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     The cultivation of innovative thinking has always been the focus and difficulty of education. The article starts from introduction about the format of IYPT.On the basis of the analysis of the YPT evaluation model and its characteristics,we investigate on the practice of cultivating students’innovative thinking combined with the author’s work experience in CUPT and JSYPT.Taking the analysis of“magnetic braking”competition in the JSYPT finals in 2014 as an example, the practical strategies of YPT evaluation model for cultivating students’ nnovative thinking are discussed.
    Research on the relationship between Raman and Born
    HOU Yu-de,XING Hong-fei
    College Physics. 2016, 35(8):  61-65. 
    Abstract ( 767 )   PDF (402KB) ( 491 )  
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    There is no a scientist who can do his research well without any relations with other colleagues.So it is a very important quality to a scientist that have the ability to deal with the relationship well.Max Born and Raman had intersection in their research work.Max Born felt sad and unhappy when he dealing with Raman.Maybe Raman had the same feeling.By reviewing the stories of Born and Raman, the people who always put himself in the other’s shoes could do things better,and the people who can not do well in personal relationships will get a severe warning.