Table of Content

15 December 2000, Volume 9 Issue 12 Previous Issue    Next Issue

GENERAL

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A POSSIBLE EXPERIMENTAL TEST ON THE GRAVITATION THEORY OF COMPLEX FIELD Tang Zhi-ming 2000, 9 (12):  881-884.  doi: 10.1088/1009-1963/9/12/001 Abstract ( 0 )   PDF (177KB) ([an error occurred while processing this directive])   By appropriately choosing additional dimensions of space-time, the mass spectrum of mesons was obtained, and the calculated results agree with the experimental data.

ATOMIC AND MOLECULAR PHYSICS

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ANALYSIS OF THE HDO ABSORPTION SPECTRUM BETWEEN 9600-10200cm-1 Wang Xiang-huai, He Sheng-gui, Hu Shui-ming, Zheng Jing-jing, Zhu Qing-shi 2000, 9 (12):  885-891.  doi: 10.1088/1009-1963/9/12/002 Abstract ( 0 )   PDF (140KB) ([an error occurred while processing this directive])   The absorption spectrum of HD16 O was recorded at a resolution of 0.02 cm-1 with a Bruker IFS 120HR Fourier Transform Spectrometer in the region of 9600-10200 cm-1. As far as we know it is the first time to record and analyze the HDO spectrum in this region which was assigned as the ν1+2ν3 and 2ν2+2ν3 bands. With the strong resonance interactions between these two bands considered, the spectroscopic parameters were optimized by the nonlinear least squares method.

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ASYMMETRY PARAMETERS AND DIFFERENTIAL CROSS SECTIONS FOR PHOTOIONIZATION-EXCITATION OF HELIUM Jiang Yu-hai, Sun Jin-feng, Zhu Zun-lue, Yang Qin-yu, Wan Ling-de 2000, 9 (12):  892-899.  doi: 10.1088/1009-1963/9/12/003 Abstract ( 0 )   PDF (213KB) ([an error occurred while processing this directive])   Asymmetry parameter β2 for photoionization of helium leaving the He+ ion in the n=2 level and differential cross sections(DCSs) in the n=2,3,4 levels with photon emission angle θ=900 are provided at photon energies 69-76.8 eV employing the R-matrix method with a 20-term target representation, in which five polarization orbitals \bar{6}l are included. The asymmetry parameter β2 and the DCS, in the n=2 level in the region of 69-73 eV, are in good agreement with available experimental and theoretical results. Above the n=3 threshold, we present new theoretical results along with measurements. No theoretical and experimental results can be used to compare with the present calculations of the DCSs for photoionization into the He+ ion in the n=3,4 levels.

CLASSICAL AREAS OF PHENOMENOLOGY

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SPECTRUM OF THE MICROMASER INJECTED WITH Λ-TYPE THREE-LEVEL ATOMS Zhang Zhi-ming, Liang Wen-Qing, Xie Sheng-wu 2000, 9 (12):  900-904.  doi: 10.1088/1009-1963/9/12/004 Abstract ( 0 )   PDF (132KB) ([an error occurred while processing this directive])   The spectrum of the micromaser injected with Λ-type three-level atoms is studied. The spectrum has a Lorentzian lineshape and its central frequency has a shift. The effects of various parameters (for example, the atomic center-of-mass velocity, the cavity-length, the one-photon detuning, the ratio of the atomic injection rate to the cavity decay rate and the number of thermal photons) on the linewidth and the frequency shift are examined. The spectrum shows very different features in different velocity regimes, i.e., in the fast-atom regime, in the intermediate-velocity-atom regime, and in the slow-atom regime.

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RAMAN-ENHANCED POLARIZATION BEATS WITH PHASE-CONJUGATION GEOMETRY Zhang Yan-peng, Hou Xun, Lu Ke-qing, Wu Hong-cai 2000, 9 (12):  905-909.  doi: 10.1088/1009-1963/9/12/005 Abstract ( 0 )   PDF (123KB) ([an error occurred while processing this directive])   The Raman-enhanced polarization beats (REPB) with phase-conjugation geometry in carbon disulfide are investigated using chaotic and phase-diffusion models. The overall accuracy of using REPB to measure the resonant frequency of Raman-active vibrational mode is determined by the relaxation rates of the Raman mode and the molecular-reorientational grating. Different stochastic models of the laser field only affect the sixth- and fourth-order coherence function. The difference between the REPB and the fourth-order coherence on ultrafast modulation spectroscopy is discussed as well from a physical viewpoint.

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RELATIONSHIP BETWEEN INTENSITY OF SURFACE SECOND HARMONIC GENERATION AND MOLECULAR STRUCTURE IN HELIX MOLECULAR FILMS Xin Li, Li Chun-fei, Li Jun-qing, Zheng Yang-dong 2000, 9 (12):  910-912.  doi: 10.1088/1009-1963/9/12/006 Abstract ( 0 )   PDF (136KB) ([an error occurred while processing this directive])   The relationship between intensity of surface Second Harmonic Generation (SHG) and the pitch, radius and azimuthal angle of molecules on the surface of helix molecular films is analyzed. The values of pitch and radius corresponding to the maximal intensity of SHG have been shown to exist. The theoretical results are compared with the experimental ones reported by M?hlman et al., and the limitation of their conclusion is also pointed out.

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RESEARCH ON VIBRATION MODES OF THE CHINESE CHIME STONE Cheng Jian-zheng, Zhang De-jun, Lan Cong-qing, Ye Chao-hui 2000, 9 (12):  913-921.  doi: 10.1088/1009-1963/9/12/007 Abstract ( 0 )   PDF (807KB) ([an error occurred while processing this directive])   Nearfield acoustical holography is a powerful tool for imaging of acoustic sources. In this article, the basic theory treating steady-state acoustic radiation with generalized holography has been discussed. By holographic imaging, the vibration characteristics of irregular objects, the Chinese ancient musical instrument, the one-tone chime stone and the two-tone chime stone provided by the Institute of Archaeology, the Museum of Hubei Province, have been researched. The results show that the ancient chime stone has two main vibration modes, which make up the base of sound produced by the instrument. As for the two-tone chime stone, it is not so long and wide as the single-tone chime stone, but thicker and smoother than the single-tone chime stone. When it is excited at different positions, although it radiates sounds of different frequencies, its vibration modes are similar. This may be related to its dimensions and shape. The research is helpful for studying the sound producing system and the radiated field characteristics of the chime stone.

PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES

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DUST-ACOUSTIC SHOCK WAVES IN THE SHEATH OF DUSTY PLASMAS Xie Bai-song, He Kai-fen, Chen Yan-ping 2000, 9 (12):  922-926.  doi: 10.1088/1009-1963/9/12/008 Abstract ( 0 )   PDF (114KB) ([an error occurred while processing this directive])   The effect of dust charging and influence of its fluctuation on dust-acoustic shock waves in the sheath region of the dusty plasma is investigated. By employing the reductive perturbation technique, the Burgers' equation is derived. The weak shock wave solution is obtained and discussed in this dust-charge-fluctuation system.

CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

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ANALYTIC EQUATION OF STATE FOR GENERALIZED LENNARD-JONES SOLID INCLUDING LOWEST-ORDER ANHARMONIC AND CORRELATION CORRECTIONS Sun Jiu-xun, Cai Ling-cang, Wu Qiang, Jing Fu-qian 2000, 9 (12):  927-933.  doi: 10.1088/1009-1963/9/12/009 Abstract ( 0 )   PDF (237KB) ([an error occurred while processing this directive])   Based on the cell model, the general formula for the free energy of solids is derived analytically with the lowest order anharmonic modification and correlation effect taken into account. Combining a method of summing over lattice sites, the analytic equation of state for generalized Lennard-Jones solid is derived. The calculations show that the agreement between theory and computer simulation is quite good and is significantly improved as compared with the numerical results in literature. The comparison of different effects shows the theory including all neighbors but only considering the lowest anharmonic and correlation effects may be a good and convenient approximation for practical solids. The approximation can be easily extended to the quantum case and other generalized potentials.

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

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FLUCTUATIONS OF FLUX LINES ON THE SURFACE OF SUPERCONDUCTOR Liu Jun-jun, Gan Zi-zhao 2000, 9 (12):  934-943.  doi: 10.1088/1009-1963/9/12/010 Abstract ( 0 )   PDF (207KB) ([an error occurred while processing this directive])   In this paper, we study the magnetic structure of the half-ring flux line ended on the surface of a superconductor. The elemental modes for these half-ring flux lines are the half-ellipse flux lines ended on and perpendicular to the surface. The statistics of these half-ring flux lines is, in a certain degree, similar to the vortex-antivortex pairs in thin superconducting films. An abrupt change of the thermodynamic properties for this system takes place at a temperature lower than Tc. It is analogous to the KT transition in thin superconducting films in certain sense.

CROSSDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY

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RESONANCE RESPONSE OF ELECTRORHEOLOGICAL FLUIDS IN VERTICAL OSCILLATION SQUEEZE FLOW Liu Li-wei, Wang Zuo-wei, Liu Ge, Jiang Yong-gang, Qiu Zhi-yong, Zhou Lu-wei 2000, 9 (12):  944-948.  doi: 10.1088/1009-1963/9/12/011 Abstract ( 0 )   PDF (143KB) ([an error occurred while processing this directive])   The resonance effect of microcrystalline cellulose/castor oil electrorheological (ER) suspensions was studied in a compressed oscillatory squeeze flow under external electric fields. The resonance frequency first increases linearly with increasing external field, and then shift to high-field plateau. The amplitudes of resonance peak increase sharply with the applied fields in the range of 0.17-1.67 kV/mm. The phase difference of the reduced displacement relative to the excitation force inverses in the case of resonance. A viscoelasticity model of the ER suspensions, which offers both the equivalent stiffness and the viscous damping, should be responsible for the appearance of resonance. The influence of the electric field on the resonance frequency and the resonance hump is consistent qualitatively with the interpretation of our proposed model. Storage modulus G' was presented for the purpose of investigating this influence.