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Table of Content

    20 February 2013 Volume 32 Issue 2
      
    著者文摘
    Solution of the evolution of time-dependent CK harmonic oscillator model by using Fresnel transformation
    . 2013, 32(2):  1-1. 
    Abstract ( 690 )   PDF (236KB) ( 504 )  
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    By using the Fresnel transformation for wave function, the solution of the evolution of time-dependent CK harmonic oscillator is obtained. The proposed method is novel and unique.
    Solution of the evolution of time-dependent CK harmonic oscillator model by using Fresnel transformation
    . 2013, 32(2):  3-3. 
    Abstract ( 700 )   PDF (345KB) ( 417 )  
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    By using the Fresnel transformation for wave function, the solution of the evolution of time-depend- ent CK harmonic oscillator is obtained. The proposed method is novel and unique.
    Distribution features of the charge density on the interface between two-layer conductive media in constant current field
    . 2013, 32(2):  7-7. 
    Abstract ( 1017 )   PDF (1418KB) ( 805 )  
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    The study of the distribution characteristics of the surface charge density in the constant current field plays an important role to understand the constant current field. The mirror principle is used to derive the formula of charge density distribution in two kinds of infinite interfaces (one is the interface of two-layer conductive medium ; another is between the conductive medium and the air) while both emission and return electrode are placed in a conductive medium. By using the software of the COMSOL, the surface charge density under the same circumstance but limited medium is calculated. The results show that on the interface between the medium and air in the homoge- nous medium, one side of the emission electrode is positive charge and the other side is negative, without charge in centre. Whether the charge on the interface between different conductive media is positive or negative is decided by the difference of two side resistivities. The value of the charge density on the interface is inversely proportional to conductivity. In the limited medium, the numerical calculation reveals quantitatively the charge distribution features in corner, edge and intersecting line on the surface. They depend on the position of the emission electrode, the return electrode and the surface geometrical structure.
    Applications of the one-dimensional monatomic chain in the study of carbon nanotube
    . 2013, 32(2):  13-13. 
    Abstract ( 824 )   PDF (476KB) ( 396 )  
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    Using the one-dimensional monatomic chain as a model, the vibrational properties of the carbon nanotube with pentagon and atomic vacancy have been investigated respectively. It explains qualitatively the reason that the two defects can induce the localized defective modes. From the calculations, it's found that the bond length on the pentagon rings is shorter than that of the hexagon rings, meaning that the force constants on the pentagon de- fect should be larger relative to those on the hexagon rings, A similar result is proved for the atomic vacancy. The effective mass of the vacancy is smaller than the normal carbon atom, at the same time, the bond length around the vacancy is shorter than the hexagon ring's. Therefore, the two kinds of defects may be considered as the ' light- mass impurity' , which can cause a new localized defect mode out of the vibrational modes of the perfect lattice, re- spectively.
    The parallel plate condenser of pole board with straight gap
    . 2013, 32(2):  18-18. 
    Abstract ( 885 )   PDF (336KB) ( 558 )  
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    The electric field of a parallel plate condenser of polar plate with straight gap is studied by using the Schwarz-Christoffel transformation in the coordinate system of the complex number, and its electric potential distri- bution and electric intensity distribution are obtained. In further, the influence of a polar plane with straight gap on capacity of supporting voltage and capacitance is discussed.
    Analysis of the angular momentum
    . 2013, 32(2):  22-22. 
    Abstract ( 838 )   PDF (399KB) ( 659 )  
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    In the process of teaching college physics, detailed analysis of some elementary concepts is impor- tant both for deeper understanding of the concepts itself and holding the idea of the modern physics, as well as pro- ceeding to later curriculums. By studying the angular momentum and its properties under the parity transformation, the concept of axial vector is introduced. The parity transformation in quantum mechanics is analyzed such that the state wave function and the field operator are classified. The important concept such as the parity is strengthened due to its importance in classifying the composite particles in elementary particle physics.
    An introduction of modeling instruction' s theory and practice in physics
    . 2013, 32(2):  25-25. 
    Abstract ( 1260 )   PDF (919KB) ( 1242 )  
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    Modeling instruction is a pedagogical aproach which was established by a theoretical physicist David Hestenes in Arizona state university. Modeling instruction can help students focus problem, construct knowledge, and solve problem under the science domain. It has been found that modeling instruction not only can develop inde- pendent learning capability, stimulate students to understand physics conception, strengthen studying interest, but also can promote physical thinking quality and achieve educational equity. Since its establishment, it has been widely and successfully employed in science, technology, engineering and mathematics instruction, as well as teacher training.
    Analysis on the two-dimensional elastic collision of two particles by relativistic mechanics
    . 2013, 32(2):  31-31. 
    Abstract ( 1235 )   PDF (278KB) ( 1194 )  
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    The two-dimensional elastic collision of two particles is studied by using relativistic mechanics. The iscrepancy between the results obtained by classical and relativistic mechanics shows the characteristics of relativistic mechanics.
    Calculation of magnetic field separated and eccentric load flow thin cylindrical by using magnetic scalar potential
    . 2013, 32(2):  33-33. 
    Abstract ( 880 )   PDF (334KB) ( 482 )  
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    In the bipolar cylindrical coordinates, the magnetic scalar potential via the Laplace equation con〉 bined with the Ampere circuital theorem is used to calculate the magnetic field stregnth around separated and eccen- tric homegeneous current-carrying thin cylinder.
    Derivation of the mass-energy relation dispense with Lorentz transformation
    . 2013, 32(2):  37-37. 
    Abstract ( 803 )   PDF (340KB) ( 830 )  
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    On the basis of the definitions for relativity momentum and relativity energy, a new derivation of the mas.s-energy relation for massive particles is presented in the relativistic dynamics according to the conservation of both momentum and energy as well as the principle of relativity. The derivation makes no use of the specific space -time transformation.
    Measuring acceleration of gravity by digital storage oscilloscope aided
    . 2013, 32(2):  40-40. 
    Abstract ( 853 )   PDF (285KB) ( 813 )  
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    When object with a magnetic is close to or away from the coil, pulse signal is induced in the coil due to the variation of magnetic flux. Digital storage oscilloscope is used to collect the pulse signal. The falling time of object can be obtained by analyzing the number of intervals of pulse signals. Thus, the value of acceleration of gravity can be gained and the motion law of free fall is verified.
    Research on nature of photo-induced birefringence of Methyl Orange dye-doped PVA
    . 2013, 32(2):  43-43. 
    Abstract ( 835 )   PDF (369KB) ( 518 )  
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    This paper introduces the course of photo-induced birefringence characteristic experiment of MO the azo dye-doped PVA thin film in modern physics experiments. The laboratory finding shows that the sample's ex- tent of reaction of photo-induced birefringence is in direct proportion to its exciting light power; in the case of certain exciting light power and 45° included angle between exciting light polarization direction and detecting light po- larization direction, sample's extent of reaction of photo-induced birefringence achieves maximum.
    Iscussion of unclear interference fringe in the experiment of measuring refractive index of plate glass
    . 2013, 32(2):  47-47. 
    Abstract ( 1041 )   PDF (287KB) ( 460 )  
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    The reason of the emergence of unclear interference fringe in measurement of refractive index of plate glass using spectrometer is analyzed. According to the similar intensity distribution of simulation and observa- tion, the wedge angle of plate glass is the main cause. Based on the contrast of interference stripe varied by reflection of plate glass in different angles, to make sure the students could observe clear interference stripe, reflection of plate glass should be chosen between 0.5 and 0.7.
    Physical principles in the security detection techniques
    . 2013, 32(2):  50-50. 
    Abstract ( 1262 )   PDF (663KB) ( 780 )  
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    Detection techniques on explosives play a vital role in security prediction and warning. Principles of physics have very important applications in the field of security detection techniques. The physical principles on several techniques used commonly or latest including X-ray detection technology, terahertz spectroscopy, infrared spectroscopy, Raman spectroscopy and surface enhanced Raman spectroscopy, and ion mobility spectrometry etc. have been introduced. And physics is expected to make new contributions in the detection techniques.
    Talk about the uncertainty relation
    . 2013, 32(2):  57-57. 
    Abstract ( 800 )   PDF (166KB) ( 618 )  
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    The uncertainty relation is proved by using the concept of scalar product and the statistical idea in order to show the reason why most textbooks usually use a kind of integral inequality to deduce the uncertainty relation. Moreover, some simply discussion is presented.
    The influence of the magnitude and the frequency of electrical field on the diffraction in liquid crystal cell
    . 2013, 32(2):  59-59. 
    Abstract ( 1231 )   PDF (405KB) ( 601 )  
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    The diffraction phenomenon occurred in a high-twisted nematic liquid (HNL) crystal cell is ob- served. It is known that such kind of diffraction is due to the fomiation of so-called Williams domain. How this dif- fraction depending on the magnitude and the frequency of the electrical AC field applied on the HNL cell is also studied in detail.