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Table of Content

    20 February 2016 Volume 35 Issue 2
      
    著者文摘
    Neutrino oscillations and Nobel Prize in physics 2015
    . 2016, 35(2):  1-1. 
    Abstract ( 809 )   PDF (544KB) ( 711 )  
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    In this article, the history of neutrinos has been briefly reviewed. The atmospheric neutrino anomaly and solar neutrino problem are introduced, and neutrino oscillations as a perfect solution to those problems are discussed in some detail. Finally, the importance of neutrino masses and the remaining unanswered questions in neutrino physics are emphasized.
    Weyl prescription based on the anti-normal ordering technology
    . 2016, 35(2):  5-5. 
    Abstract ( 805 )   PDF (487KB) ( 448 )  
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    Wigner operator and Weyl prescription are studied by virtue of the skill of differential-integral and the method of operators' differential quotient. The differential formula of Wigner operator in normal ordering is given, and new differential formulae of some special functions are obtained. It is more important that the integral divergent difficulty is smoothed away and the differential formula of Wigner operator and the Weyl prescription in anti-normal ordering are derived. Several examples are calculated.
    Some new cognitions for the uncertainty principle
    . 2016, 35(2):  11-11. 
    Abstract ( 838 )   PDF (353KB) ( 561 )  
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    This paper discusses the expression of the position-momentum uncertainty relation for the case of a free particle moving in a one-dimensional finite region, which is subjected to the box normalization treatment. It is found that for such a specific physical situation, although the physical thesis that the position coordinate and the momentum of a particle cannot be exactly measured simultaneously certainly holds, the mathematical form of the usual position-momentum uncertainty relation needs some modifications. In this paper the concrete form of the position-momentum uncertainty relation for such a situation has been obtained, which deepens our understanding of the uncertainty principle in quantum mechanics. From the viewpoint of the cognition of the momentum uncertainty of a free particle subjected to the box normalization, a discussion of the physical cognition of the infinite volume limit is also made.
    An analysis of oscillation and rotation of swing with the principle of work and energy
    . 2016, 35(2):  14-14. 
    Abstract ( 1062 )   PDF (375KB) ( 798 )  
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    By using internal force doing work in non-inertial frame, the oscillation and rotation of swing are analyzed based on the principle of work and energy.
    The condition for two conductor spheres with the same charge always keep repel
    . 2016, 35(2):  17-17. 
    Abstract ( 1069 )   PDF (367KB) ( 574 )  
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    When two conductor spheres are charged with the same charge, their interaction is an interesting problem for both research and teaching. Through the qualitative discussion and the numerical simulation, the condition for the two spheres with the same charge always keep repel is extended. Based on the relationship of the electric potential energy and the distance between two spheres, the general condition for two spheres are always repelling is given. It is found that the previous condition with exactly ratio of radius and charges is actually the sufficient condition. In more general conditions, two spheres with the same charges can keep repel all along.
    Electromagnetic field from a charging circular parallel plate capacitor
    . 2016, 35(2):  21-21. 
    Abstract ( 1828 )   PDF (855KB) ( 802 )  
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    The electromagnetic field from a charging circular parallel plate capacitor is numerically studied by using the Mathematica. The spatial distributions of the electric potential and the electric field intensity as well as the magnetic induction intensity are given. The edge effect of the electromagnetic field is discussed.
    Application of the Minkowski space-time diagram to teaching of the Einstein theory of relativity
    . 2016, 35(2):  27-27. 
    Abstract ( 1224 )   PDF (363KB) ( 1090 )  
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    In this article, the two-dimensional Einstein theory of relativity in college physics, and Minkowski space-time diagram is applied to teaching of the there is an intuitive reveal on the inner connections between simultaneous relativity and space-time in special relativity as well as time dilation and length contraction.
    A new type of heat capacity measurement instrument
    . 2016, 35(2):  30-30. 
    Abstract ( 784 )   PDF (278KB) ( 502 )  
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    Specific heat capacity measurement is an important basic experiment. The hybrid method is often used to measure, but the present instrument leads to a large error of experiment result. This paper proposes a hybrid method of measuring heat capacity of the new instrument, which has quick heat exchange, temperature measurement accuracy, less heat loss as well as the characteristics can be calculated, etc. The instrument improves accuracy of determination measurement and is easy to operate.
    A brief introduction to dark matter
    . 2016, 35(2):  32-32. 
    Abstract ( 910 )   PDF (528KB) ( 801 )  
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    Dark matter is a big challenge to the physics and astronomy nowadays. We briefly review the history of the discovery of dark matter, the evidence of its existence from observation, and its basic properties. We introduce some prominent candidates for dark matter and the progress in this detection.
    Introduction of 《 Time Travel》 in lecture and its relativity analysis
    . 2016, 35(2):  37-37. 
    Abstract ( 902 )   PDF (492KB) ( 779 )  
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    Science documentary 《Time Travel》 is outlined theoretically for realistic ideas of traveling through time. It is a good multi-media material for teaching relativity theory. Data in the film, such as to orbit the black hole and GPS, are demonstrated by using the theory of relativity. The calculation methods of time dilation under the strong and weak gravitational field are discussed. Under the weak field it can be directly used time dilation equation in special relativity and gravitational time dilation equation in general relativity. The comprehensive effect is equal to the sum of the above two results approximately.
    《 Six Ideas that shaped physics》 and its practice course -- Taking the practice of the "Introduction to the physics" course in Washington University as an example
    . 2016, 35(2):  41-41. 
    Abstract ( 1088 )   PDF (1257KB) ( 553 )  
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    The 《Six Ideas》 (short for 《Six ideas that shaped physics》) has been used by all over the world more than 100 colleges and universities, using the six ideas that shaped physics as a line to construct a frame of this set of textbooks has breached the mode of construction of traditional physics textbooks which in order of mechanics, thermodynamics, electromagnetics and optics. Each units of the 《 Six Ideas》 using a historical development of story line, to emphasize the inherent idea and application conditions of concepts and laws, and the text and/or graphics translation problem framework model to translate some problems. The content of each unit is not only suitable for the students to learn by themselves, but also for teachers classroom teaching tailored for 50 minutes; it is indeed a good physics textbook which suitable for students "active learning" and teachers teaching; one typical practice of the "Introduction to the physics" course in Washington University in St. Louis will be taken as an example, based on the Material of E9.
    Study of avoided crossing in coupled acoustic resonant tube
    . 2016, 35(2):  48-48. 
    Abstract ( 674 )   PDF (350KB) ( 557 )  
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    In this paper, we apply acoustical power method to measure the frequency characteristics of the couple acoustic resonant tube under different coupling strengths. Our experiments show that the phenomenon of avoided crossing in coupled acoustic resonant tube is more obvious as the coupling strength increases. The mathematical similarity between acoustic systems and quantum mechanical is also shown.
    Acoustic interference in uniform motion medium
    . 2016, 35(2):  52-52. 
    Abstract ( 886 )   PDF (340KB) ( 410 )  
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    In the paper, we discuss the interference of two sound waves engendered by static sound sources in the uniform motion medium, calculate the time distance of the equiphase waves simultaneously engendered by the two sound sources to a point. It is multiplied by the pulsatance to obtain the phase difference, then we get the equation of equiphase point. Finally, we discuss the interferences in several special positions and illustrate related applications.
    Theory and experimental verification of measuring mercury lamp wavelength by the grating least deviation angle method
    . 2016, 35(2):  56-56. 
    Abstract ( 2056 )   PDF (339KB) ( 941 )  
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    Through theoretical derivation, the expression of the minimum deviation angle is given. We get the accurate values of the minimum deviation angle by measure. The experimental results show that the measurement is more accurate than symmetry method. The results also show that the grating constant is one of the reasons of the experimental error.
    The profound friendship between Born and Einstein
    . 2016, 35(2):  60-60. 
    Abstract ( 961 )   PDF (562KB) ( 735 )  
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    Relativity and quantum mechanics were the central contributions to physics in 20^th century. Relativity nearly was Einstein's own work. But quantum mechanics was come from the cooperation by Max Born and his students. In all their life, Born and Einstein were good friends. Understanding their contacts, their friendship, and the academic arguments between them, is a good experiments or education process to today's people.