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Table of Content

    20 March 2013 Volume 32 Issue 3
      
    著者文摘
    The diffraction spectra of the waveguide grating:analysis and experiment
    . 2013, 32(3):  1-1. 
    Abstract ( 874 )   PDF (668KB) ( 435 )  
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    The analytical solution of the diffraction spectra of waveguide grating is deduced. Then the influence of the thickness of the waveguide and the period of the grating on the diffraction spectra is studied by using the analytical solution. It is found that the resonance wavelength moves to the red with increasing the period of the grating (the thickness of the waveguide) , the tuning rate is measured to be about 1 nm (0. 125 nm) spectral shift per 1 nm increasing in grating period (the waveguide thickness). The theoretical analysis is in well agreement with the experimental result. Some potential applications of the waveguide grating in the laser cavity and the highly directional emission device are also discussed.
    Propagation of a transverse pulse along a rope in gravity field
    . 2013, 32(3):  4-4. 
    Abstract ( 827 )   PDF (353KB) ( 533 )  
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    The problem of transit time of a transverse pulse along a soft rope in gravity field is investigated by theoretical guess and experimental observation.
    Laws of conservation in α-particle scattering
    . 2013, 32(3):  8-8. 
    Abstract ( 1143 )   PDF (241KB) ( 733 )  
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    Starting from two basic conservation laws for the central force, the far-branch hyperbola of scattering orbit of the α-particle is deduced. According to the geometric relationship, the sighting range being equal to the orbital semi-imaginary axis is proved, thus the relationship between the sighting range and scattering angle is easily derived.
    Discussion on an example of rigid body
    . 2013, 32(3):  10-10. 
    Abstract ( 854 )   PDF (182KB) ( 414 )  
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    We give analysis of an example of rigid body in college physics, point out nonphysical factors and suggest instructional discussion.
    Discussion on relationship between uncertainty principle and measurement
    . 2013, 32(3):  12-12. 
    Abstract ( 969 )   PDF (272KB) ( 570 )  
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    The uncertainty principle is a very important relation in quantum mechanics. Many physicists, including W. Heisenberg, believe that this principle has a close relationship to measurement, though it is a consequence of the statistical interpretation. At the same time, some other physicists have opposite views on it, and there is no relevant analysis in many textbooks. In this paper, with the help of the up-to-date scientific discoveries, the essence of uncertainty principle and the conclusion, that the uncertainty principle has no relationship with measurement are presented.
    Discussion on non-relativistic approximation of Dirac equation by means of Foldy-Wouthuysen transformation
    . 2013, 32(3):  15-15. 
    Abstract ( 1008 )   PDF (303KB) ( 2197 )  
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    The non-relativistic approximation of Dirac equation is discussed by means of method of Foldy- Wouthuysen transformation. The recurrence fomiulas of Hamiltonian and wave function are given out.
    Research progress and inspiration of analogical scaffolding and the teaching of abstract ideas in physics
    . 2013, 32(3):  19-19. 
    Abstract ( 873 )   PDF (485KB) ( 708 )  
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    This paper expounds mainly the theoretical basis, research progress and results of analogical scaffolding. Based on these studies, we introduce the use of this analogy model on the teaching of abstract ideas in physics.
    The uncertainty evaluation of NTC thermistor calibration equation
    . 2013, 32(3):  23-23. 
    Abstract ( 931 )   PDF (354KB) ( 1495 )  
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    In order to improve measuring-temperature accuracy of the NTC thermistors, we discuss two NTC thermistors calibration equations. Firstly, we use the least square method to solve coefficients of equation with MATLAB, and then use a measurement standard uncertainty on two kinds of correction equations to fit precision evaluation, achieve high precision NTC thermistor correction equation. Finally, based on the cases of water temperature measureruent in the laboratory, NTC thermistor linear correction equation can be used in the actual teaching experiment environment.
    Application of digital instruction in teaching university physics
    . 2013, 32(3):  27-27. 
    Abstract ( 816 )   PDF (1066KB) ( 603 )  
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    Based the education reform project "Innovation in teaching general physics using information technique" and the platform for digital instruction in physics teaching, new teaching methods are adopted with the support of digital instruction technique. These methods can increase students' interest in physics, enhance their understanding in physics concepts and the problem solving abilities. The reform is widely accepted by the students and with satisfying results.
    An exploration and practice in theoretical mechanics the elaborate course construction of in local normal university
    . 2013, 32(3):  32-32. 
    Abstract ( 842 )   PDF (533KB) ( 610 )  
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    Construction of elaborate course plays a very important role in improving the teaching quality in universities. According to the requirements of local elementary education development, the group of theoretical mechanics course in Nanyang Normal University highlights the characteristics of teacher education, practice and explores the elaborate course construction of theoretical mechanics based on the talent training goal, the idea of teaching, teaching staff, content system, teaching mode, valuation system etc. Good results have been obtained in training the innovative talented persons who have solid foundation, strong practical ability and high comprehensive quality in normal university.
    Discussion on system with two degrees of freedom vibration in rotating coordinate system
    . 2013, 32(3):  37-37. 
    Abstract ( 867 )   PDF (326KB) ( 688 )  
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    According to Newton's law of motion, we establish a couple of inhomogeneous differential equations for vibration of motion with two degrees of freedom in rotating coordinate system. The roots of equation by transforming them into the sum between the roots of a couple of homogeneous and the roots of a couple of linear equation in two unknowns are obtained. By analyzing the eigenvalues of equations, we conclude three laws of motion and get the formula of the vibration of system.
    Discussions on system response stimulated by periodic signal and causal periodic signal
    . 2013, 32(3):  40-40. 
    Abstract ( 1207 )   PDF (327KB) ( 309 )  
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    The response function of dynamic system is analyzed, which is stimulated by the periodic signal and causal periodic signal through the analysis of dynamic system response function. By taking into account the second -order RLC circuit as an example, the relationship of the two kinds of response functions is shown specifically, and the rationality of using causal periodic signal instead of periodic signal in the experiment is illustrated.
    The influence of mass of spring on oscillatory period
    . 2013, 32(3):  44-44. 
    Abstract ( 1337 )   PDF (242KB) ( 1024 )  
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    An approximate fomiula of the spring's effective mass is presented under the condition of the spring of non-negligible mass. By using this formula, we consider exactly the influence of spring's mass on oscillatory period.
    Studies of the group velocity of TM modes in planar waveguide
    . 2013, 32(3):  46-46. 
    Abstract ( 1103 )   PDF (241KB) ( 790 )  
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    With the aid of Mathematic software, we calculate the group velocity of TM mode in planar waveguide by dividing energy flux density by energy density, and get the same result by performing the derivative of the propagation constant with respect to the angular frequency of the guided mode, which demonstrates that energy propagates with the group velocity.
    Two methods for general laws of reflection and refraction for metasurface with phase discontinuity
    . 2013, 32(3):  49-49. 
    Abstract ( 2367 )   PDF (483KB) ( 3794 )  
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    Considering the abrupt phase shift at the interface between the two media, the general reflection and refraction laws at the metasurfaee with the abrupt phase shift are derived by the two methods based on Fermat's principle and the boundary conditions of continuity, respectively. It is found that the tradition reflection and refraction laws are the special cases of the generalized reflection and refraction laws when the phase shift gradient is equal to zero. Based on the generalized laws of reflection and refraction, the occurrence conditions of the total internal reflection and the full transmission are given and the effect of the refraction index and the phase shift gradient are discussed. It is shown that the arbitrary controlling of the electromagnetic waves can be easily achieved.
    A method of simultaneously homogenizing boundary conditions and differential equation
    . 2013, 32(3):  53-53. 
    Abstract ( 1771 )   PDF (476KB) ( 1036 )  
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    One of the un-determined functions methods for solving the deterministic problems with non-homogeneous boundary conditions by using the method of variable separation has been presented, which can homogenize boundary conditions and differential equation simultaneously. Also the deterministic problems of three typical kinds of mathematical physical equations with the first, the second or the third type of the non-homogeneous boundary conditions are discussed, respectively. The specific conclusions and the solving model are presented.
    Analytical solution of the eigenvalue problem in isosceles right triangle zero via analytic continuation
    . 2013, 32(3):  59-59. 
    Abstract ( 761 )   PDF (242KB) ( 369 )  
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    By discussing on the symmetrical solution or antisymmetrical solution on the square, we obtain the analytical solution of the eigenvalue problem in the isosceles right triangle zero with fixed or free boundary condition on hypotenuse via analytic continuation.