Loading...

Table of Content

    20 April 2008 Volume 27 Issue 4
      
    著者文摘
    Why dynamical variables should be represented by Hermitian operators in quantum mechanics
    . 2008, 27(4):  1-1. 
    Abstract ( 1839 )   PDF (446KB) ( 1256 )  
    Related Articles | Metrics
    Based on the mathematical formulation of quantum mechanics, the four properties of Hermitian operators,i, e., linearality, completeness of eigenstates, orthogonality of eigenstates and realness of eigenvalues, are discussed in detail. Every property is considered from both positive and negative view which clarify their meanings.
    General solving method of two modes coupled harmonic oscillators
    . 2008, 27(4):  7-7. 
    Abstract ( 1265 )   PDF (199KB) ( 750 )  
    Related Articles | Metrics
    Hamiltonian of two modes coupled harmonic oscillators is general quadric form of generalized coordinates and momenta. After coordinate transformation, it can be expressed as standard quadric form under new bases. Because canonical commutation relation is satisfied among new coordinates, creation operator and annihilation operator are introduced. Thus, coupling between modes is eliminated and Hamiltonian can be simplified as two mode independent harmonic oscillators, problem is solved. This method can be generalized in solving non- identical n modes coupled harmonic oscillators.
    A discussion about the relation of directions of phase constant and attenuation constant in conductive media
    . 2008, 27(4):  10-10. 
    Abstract ( 814 )   PDF (214KB) ( 449 )  
    Related Articles | Metrics
    The conclusion is analyzed and deduced again, which was presented in the reference that the phase constant and amplitude attenuation constant of electromagnetic wave satisfies constant relation when the inhomogeneous electromagnetic wave propagates in same and homogeneous conductive medium. Based on the boundary conditions of electromagnetic wave at the interface of conductive media, the expression of phase constant, amplitude attenuation constant and the sine of the angle between two constants and the interface normal are derived under two conditions. The results show that the phase constant and attenuation constant of electromagnetic wave doesn't satisfy constant relation when the electromagnetic wave propagates in same conductive medium, generally speaking.
    Explaining tidal phenomenon from hydrostatics viewpoint
    . 2008, 27(4):  13-13. 
    Abstract ( 774 )   PDF (296KB) ( 376 )  
    Related Articles | Metrics
    The shape of ocean tides and problems of tidal fluctuation are discussed from hydrostatics standpoint, and the factor of the rotation of the Earth is considered in calculation.
    The magnetic field inside an eccentric cable
    . 2008, 27(4):  16-16. 
    Abstract ( 893 )   PDF (257KB) ( 519 )  
    Related Articles | Metrics
    Using the linear conversion in the complex coordinate system, the distribution of the magnetic field inside an eccentric cable is calculated, and then lines of magnetic induction are given.
    Analysis on Hn^+ cluster ion movement in Penning ion trap
    . 2008, 27(4):  19-19. 
    Abstract ( 713 )   PDF (210KB) ( 313 )  
    Related Articles | Metrics
    Based on the structure of Penning ion trap adopted in experiment and the distributing character of electromagnetic field, ion movement equation is educed and resolved and the cluster ion three kinds of motions are analyzed in detail.
    How it is obtained the boundary condition A1t = A2t of vector potential
    . 2008, 27(4):  22-22. 
    Abstract ( 745 )   PDF (215KB) ( 238 )  
    Related Articles | Metrics
    It is pointed out that the way of deriving boundary condition A1t = A2t is improper given by some authors. It is shown that the correct way of obtaining the boundary condition A1t= A2t. The relationship between of en·(Δ↓× A2-Δ↓×A1)=0 and A1t=A2t is explained.
    A simple solution to initial value of impulse response in dynamic circuit
    . 2008, 27(4):  25-25. 
    Abstract ( 1052 )   PDF (231KB) ( 315 )  
    Related Articles | Metrics
    The solution dynamic circuit impulse response initial value and dynamic circuit response initial value another simple method are given. After switching, the original state of circuit capacity voltage or circuit inductance current hasn't the jump normally, but sometimes there can be the jump. When it hard to determine for a while, the circuit may be changed into its s -domain model firstly, then the 0- value has been taken into the switched circuit model, lastly the Laplace transform's initial value theorem was applied, which solved the t - domain response original state 0 + value problem in the s -domain. This method is applicable to various circuits extensively.
    Go forward layer upon layer, with beauty and significance
    . 2008, 27(4):  28-28. 
    Abstract ( 860 )   PDF (392KB) ( 399 )  
    Related Articles | Metrics
    This article takes "quantum behavior" which is one chapter of "teaching materials" as an example, study Feynman's physics teaching style, it is pointed out that Feynman's "quantum behavior" teaching going forward one by one layer upon layer, and growing better.
    Analyzing errors caused by experimenters in Millikan's oil-drop experiment
    . 2008, 27(4):  33-33. 
    Abstract ( 1193 )   PDF (288KB) ( 583 )  
    Related Articles | Metrics
    The errors caused by experimenters in Millikans oil-drop experiment are studied and analysed. Author thoroughly analyzes time ( t ) error, voltage (U) error and length ( L ) error while author lists the charts. After analyzing the different group errors, author presents a conclusion.
    The measurement of ultrashort pulse width using a simple autocorrelator
    . 2008, 27(4):  37-37. 
    Abstract ( 869 )   PDF (454KB) ( 421 )  
    Related Articles | Metrics
    The femtosecond optical pulse width of ultrashort laser is measured by using a simple autocorrelator. The measured result nearly accords with the theoretic result. In addition, the influence of optical apparatus in the experiment on the optical pulse width is analyzed.
    The research on the scale-free networks model
    . 2008, 27(4):  43-43. 
    Abstract ( 767 )   PDF (389KB) ( 455 )  
    Related Articles | Metrics
    The basic character of the scale-free networks is analysed on the base of the statistical mechanics, the conformation principium of B-A and correctional model are introduced, owing to the shortage, a new model is designed, the new model could explain the phenomena of epidemic recrudescence.
    Application of physics on modern automobile ABS
    . 2008, 27(4):  48-48. 
    Abstract ( 667 )   PDF (236KB) ( 335 )  
    Related Articles | Metrics
    With the vehicle speed increased, the density of road traffic increased, the safety car performance requirements have become more sophisticated. Vehicle anti-lock braking system (ABS) came into being, it is based on the traditional basis of the braking system, electronic control technology, the wheel brake to prevent the wheel holds dead electromechanical integration of a system. Many of them applied mechanics, electricity, magnetism, such as hydraulic theory of physics, through the discussion of ABS understanding of the physics of modern technology application.
    Reflection and refraction characters at the interfaces of the positive and negative media
    . 2008, 27(4):  51-51. 
    Abstract ( 790 )   PDF (262KB) ( 297 )  
    Related Articles | Metrics
    The basic character at the interfaces of the positive and negative media is studied. The reflection coefficient and refraction coefficient are also given; the analysis shows the versatility of the principle of least action, Snell's law and Fresnell's law in the research on the left-handed material, and the negative refraction effect is explained.