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Table of Content

    20 July 2013 Volume 32 Issue 7
      
    著者文摘
    Visualization in scientific computing and computational physics
    . 2013, 32(7):  2-2. 
    Abstract ( 820 )   PDF (1656KB) ( 501 )  
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    Visualization in scientific computing is an important application field in computer graphics. Visual- ization converts enormous data into intuitive images, which changes numerical study into graphic study. It is a sub- sequent approach and a most powerful method for studying numerical computing results in computational physics. Thus, visualization in scientific computing and graphics study should be learned in computational physics. We in- troduce our experiences of this aspect in this article.
    Visualization in scientific computing and computational physics
    . 2013, 32(7):  10-10. 
    Abstract ( 808 )   PDF (256KB) ( 408 )  
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    Visualization in scientific computing is an important application field in computer graphics. Visual- ization converts enormous data into intuitive images, which changes numerical study into graphic study. It is a sub- sequent approach and a most powerful method for studying numerical computing results in computational physics. Thus, visualization in scientific computing and graphics study should be learned in computational physics. We in- troduce our experiences of this aspect in this article.
    Analysis of nuclear decay energy in the near of the drip lines of proton and neutron
    . 2013, 32(7):  13-13. 
    Abstract ( 862 )   PDF (460KB) ( 384 )  
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    The dependence of decay energy Ea on the atomic mass munber A and charge number Z in the near of the drip lines of proton and neutron is analyzed.
    Discussion on the fourth problem of eighth national undergraduate mechanics contest
    . 2013, 32(7):  17-17. 
    Abstract ( 680 )   PDF (248KB) ( 377 )  
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    This paper discusses a question of the fourth problem of national ZhOU Pei-yuan undergraduate me- chanical contest in 2011 in detail, and puts forward different views to the original answer.
    Example of Maxwelrs speed distribution law
    . 2013, 32(7):  20-20. 
    Abstract ( 899 )   PDF (209KB) ( 903 )  
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    With the Maxwell's speed distribution law, we analyze quantitatively some real problems. For ex- ample, we explain why there is no atmosphere on the moon and why there is a few concentrations of gases with small molecular mass on the earth's atmosphere, etc. , which should enhance the enthusiasm of students for learning physics.
    Analysis of the propagation characteristic for uniform plane electromagnetic wave in multilayered medium
    . 2013, 32(7):  22-22. 
    Abstract ( 1179 )   PDF (351KB) ( 1219 )  
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    With regard to the propagation model of electromagnetic wave in muhilayered medium, the propaga- tion behavior of electromagnetic wave through the medium layers and their interfaces are analyzed. The transmission matrices of the medium layers and the whole multilayered medium are presented,the transmission equation of elec- tromagnetic wave through muhilayered medium is derived. Then the theoretical formula based on the reflection coef- ficient and the transmission coefficient of the electromagnetic wave in muhilayered medium are obtained.
    Analysis half-wave loss of electromagnetic wave
    . 2013, 32(7):  25-25. 
    Abstract ( 1480 )   PDF (354KB) ( 786 )  
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    By using the electric vector expressions of electromagnetic waves after reflection and refraction at the boundary surface of two types media, the article gets a mathematics expression to explain quantitatively the pha- sic variation of electric vector before and after reflecting. According to the Brewster angle, the phasic variation of the reflected wave and incident wave of electric vector for differently incident angles are discussed. Considering the menbrane of silicon dioxide as an example, the index of refraction vary with wavelengths and the variation trend of the wave path-difference are discussed under different wavelengths of electromagnetic waves entering membrane from air.
    on sound attenuation acoustic location method for water metal pipeline leakage
    . 2013, 32(7):  29-29. 
    Abstract ( 811 )   PDF (339KB) ( 368 )  
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    The leakage acoustic wave on the leak is used to locate the water metal pipe line leakage. Accord- ing to generation mechanism of the metal pipeline leakage acoustic wave and the signal attenuation characteristic of leakage acoustic, we use the piezoelectric ceramic sensor together with the amplifying circuit in the simulation of water supply pipe for pipeline leakage experiment, and apply Audition and Origin softwares for experiment to ana- lyze the leakage acoustic signal. The experimental results show that the measurement of metal pipeline leakage a- coustic wave amplitude attenuation of signals is practicable for the detection of metal pipe leak location.
    Coulomb blockade phenomean and its application in the electronic nanodevices
    . 2013, 32(7):  33-33. 
    Abstract ( 1919 )   PDF (445KB) ( 1403 )  
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    The coulomb blockade effect in the single tunnel junction and dual tunnel junction is introduced and the physical process of single electron tunneling is analyzed. We discuss the principle that how to control the single electron tunneling with coulomb blockade in single electron box. The specific application of coulomb blocking effect in the single electron transistor and its development prospect are also introduced.
    Investigation of diffusion of chemical elements in rotating stars
    . 2013, 32(7):  37-37. 
    Abstract ( 883 )   PDF (604KB) ( 332 )  
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    Three diffusion coefficients which can affect the diffusion process are calculated. The effects of the chemical elements mixing are given according to the diffusion equation of the chemical elements. It is shown that meridional circulation is the main driving mechanism for the transport of angular momentum while shear turbulence is the main driving mechanism for the transport of chemical elements. The larger horizontal turbulence tends to in- crease diffusion efficiency of meridional circulation and shear turbulence. The diffusion effect favours the transporta- tion of helium and nitrogen to the surface of rotating stars and a large convective core. The diffusion of the chemical element can make the star to have a higher luminosities and a lower temperature in the center of the star and have an important effect on the structure and evolutinn of the star.
    Image potential of a three-layered heterostructure
    . 2013, 32(7):  44-44. 
    Abstract ( 804 )   PDF (242KB) ( 671 )  
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    The electrostatics of a three-layered planar heterostructure is studied. The electric potential, the im- age force, and the image potential in each layer are obtained.
    Heavy-ion cancer therapy with the FLUKA Monte-Carlo simulations
    . 2013, 32(7):  47-47. 
    Abstract ( 917 )   PDF (778KB) ( 595 )  
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    The Heavy-ion cancer therapy, as a new radiotherapy approach, cures malignant tumours by irradi- ating tumours with high-energy charged heavy-ion beams produced by large-scale heavy-ion accelerators. In com- parison with traditional and conventional radiotherapies, the heavy-ion therapy has a unique Bragg peak as well as high relative biological effectiveness(RBE) , thus it has attracted lots of attentions and has been one of the frontiers in radiotherapies. Meanwhile, as a highlight of nuclear technologies, the heavy-ion therapy has often been intro- duced into the relevant training programs. Due to the need of large-scale heavy-ion accelerators, however, it is hard to have such educational experiments in college. Here we report a virtual experiment for demonstrating the general concept of heavy-ion therapy with the FLUKA Monte-Carlo simulations. In this experiment, it is possible to simulate the whole process of carbon ion radiotherapy, from optimizing the heavy-ion beam to finalizing the best treatment. This experiment is demonstrated to be very helpful for students to understand the interaction of heavy ion with matter and the principle of heavy-ion therapy.
    Error estimation in astronomy
    . 2013, 32(7):  51-51. 
    Abstract ( 902 )   PDF (416KB) ( 527 )  
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    There are many error estimation methods commonly used in astronomy. We must pay attention to their applicable conditions before using them. Most of these methods are based on the principle of statistics, which include traditional parameter and confidence interval estimation, and brute-force grids, varying chi-square, the Fisher matrix, and Monte-Carlo methods in the case of model-based parameter estimates. They have become the most powerful tools in data analysis for astronomers.
    Introducing scientific documentaries in astronomical general courses
    . 2013, 32(7):  55-55. 
    Abstract ( 643 )   PDF (437KB) ( 868 )  
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    Scientific documentary is one of the important methods to spread scientific knowledge. It can tell science in a lively and visualized way at multiple points of views, which is also the purpose of scientific general ed- ucational courses. In this article, we introduce some excellent astronomical documentaries, and presented our expe- rience and suggestion on how to introduce scientific documentaries in astronomical general courses by taking the course of "Introduction of Planetary Science" as an example.