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Volume 12 Issue 3
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Original Articles
Hopf Structure for a Two-Parameter Deformed Boson Oscillator Algebra
ZHOU Huanqiang, GUAN Xiwen, HE Jingsong
Chin. Phys. Lett. 1995, 12 (3): 129-131 .  
Abstract   PDF(pc) (5844KB) ( 888 )
The Hopf algebraic structure, i. e. , comultiplication, coinverse and counit, is presented for a two-parameter deformed boson oscillator algebra. This result shows that the two-parameter deformed boson oscillator algebra is a Hopf algebra which is neither commutative nor cocommutative.
Coherent State of N Components and Cycle Representation
ZENG Gaojian, KUANG Leman, LI Jinhui
Chin. Phys. Lett. 1995, 12 (3): 132-135 .  
Abstract   PDF(pc) (128KB) ( 383 )
In this paper, we construct a type of coherent state with N components, and use it to span cycle representations of the Lie algebras SU(2), SU(1,l) and the Lit: superalgebra OSP( 1,2). The method for constructing cycle representation may be generalized to other Lie algebras and Lie superalgebras.
Test of Abnormally Large Coherent Scattering Cross Section Using Solar-Neutrino
LUO Jun, CHEN Xiao, LI Jianguo, FAN Shuhua, LI Fangyu
Chin. Phys. Lett. 1995, 12 (3): 136-139 .  
Abstract   PDF(pc) (183KB) ( 418 )
We have carried out a high precision torsion balance experiment in searching for abnormally large coherent scattering cross sections between a sapphire crystal and solar-neutrino. According to the hypothesis and the experimental results presented by J. Weber, a diurnal effect, which was 60 times larger than the noise level, should he observed obviously, but no significant diurnal effects were found at the level of 8.1 x 10-8 dyn in our experiment.
Calculations of the Decay Constant and Radius of the Pion
WAN Shaolong, ZHOU Jiange, CHEN Qinghu, WANG Kelin
Chin. Phys. Lett. 1995, 12 (3): 140-143 .  
Abstract   PDF(pc) (147KB) ( 471 )
We calculated the decay constant and radius of the pion in the framework of the Bethe-Salpeter equation with the vector-vector-type flat-bottom potential. The calculated results, fπ =102MeV and < rπ2>1/2 =0.632fm, are close to experimental values of fπ = 93 MeV and < rπ2>1/2 = 0.663± 0.023fm.

Isovector Dipole Giant Resonances: a Relativistic Vlasov Equation Approach
ZHOU Baosen, CAI Yanhuang, ZHU Zhiyuan
Chin. Phys. Lett. 1995, 12 (3): 144-147 .  
Abstract   PDF(pc) (208KB) ( 441 )
In the framework of relativistic quantum hadron dynamical theory, under semiclassical approximation and taking the vacuum fluctuation into account, a relativistic Vlasov equation (RVE) has been derived. Using RVE and considering other relativistic effects, we have studied the isovector dipole giant resonances built on ground state in spherical nuclei. The main results shown that the resonance energies for each multipole are larger than those obtained from the non-relativistic classical Vlasov approach. But by means of choosing a reasonable symmetry potential as 100MeV, the relativistic results can fit the experimental results very well.
Study of Giant Dipole Resonance in Hot Rotating Nucleus 132Ce
ZHU Lihua, HUANG Zhengde, HOU Long, DING Dazhao, ZHANG Peihua, ZHAO Zhizheng
Chin. Phys. Lett. 1995, 12 (3): 148-151 .  
Abstract   PDF(pc) (233KB) ( 467 )
High-energy γ-rays from the deexcitation of giant dipole resonance have been measured from the decay of compound nucleus 132Ce* formed by the 16O+116Sn reaction at an incident particle energy of 85.0MeV of 16O. The γ-ray multiplicity distribution of this reaction is calibrated with a multiplicity filter composed of 14 hexagonal BGO crystals. The shape evolution of the 132Ce* has been studied as a function of spin. The results reveal that the deformation parameter of prolate 132Ce reduces when spin increases.

Resonance Profiles of Mg 3pns Autoionizing States
DAI Changjian (C. J. Dai)
Chin. Phys. Lett. 1995, 12 (3): 152-155 .  
Abstract   PDF(pc) (201KB) ( 374 )
Multichannel quantum-defect theory is combined with the R-matrix calculations to study the resonance lineshape of autoionizing 3pns state of atomic magnesium. The R-matrices calculated with different reaction volumes hardly affect the total cross section of photoionization of the Mg 3sns Rydberg state. The comparison between theoretical and experimental results fs furnished.
Nonclassical Features Interchange Between the Cavity Field and Quantized Trap
ZENG Heping, LIN Fucheng
Chin. Phys. Lett. 1995, 12 (3): 156-159 .  
Abstract   PDF(pc) (220KB) ( 376 )
A novel recipe is proposed to generate nonclassical vibrational states of the center-of mass motions of ions in a quantized trap, based on the quantum conversion between the quantum cavity fields and the quantized trap. It is shown that, when an ion trap system interacts with the eigen mode of a single-mode Fabry-Pérot cavity where the trap was set in, and a particularly selected external laser pulse through Raman transitions, the interchange of the quantum features between the quantum light states and the quantized trap states occurs. This kind of quantum conversion can be used to prepare some nonclassical trap states in an ion trap as well as to measure the properties of initial nonclassical vibrational states.

Temperature Dependence of Transverse Mode Evolution in Vertical Cavity Surface-Emitting Lasers
ZHAO Yi-Giang, John G. McInerney
Chin. Phys. Lett. 1995, 12 (3): 160-163 .  
Abstract   PDF(pc) (210KB) ( 523 )
We have observed time-resolved spectra and spontaneous near-field profiles of vertical cavity surface-emitting laser, and have considered possible reasons for the origin of multiple transverse modes. The results show that, even under low-duty pulsed operation, the evolution of temperature profiles plays a dominant role in determing the transverse mode behaviour.
Observation of Beating Between Broadband Lights
YU Zuhe, JIANG Qian, MI Xin, FU Panming
Chin. Phys. Lett. 1995, 12 (3): 164-166 .  
Abstract   PDF(pc) (168KB) ( 390 )
We have observed beating between two broadband light sources of linewidths 4.3 and 2.3nm by a method of time-delayed laser-induced double gratings. We explain the signal modulation by relating the signal intensity to the autocorrelation function of a field which consists of two frequency components.
Effects of Poloidal Rotation and Medium-Z Impurity Radiation on MARFE Instability in Tokamak Edge
CHEN Xiaoping, GAO Qingdi
Chin. Phys. Lett. 1995, 12 (3): 167-170 .  
Abstract   PDF(pc) (196KB) ( 418 )
Multifaceted asymmetric radiation from the edges (MARFEs) are studied on the basis of radiative condensation instability. The role of medium-Z impurity radiation and its association with the soft density limit are examined. A rigid poloidal rotation has been introduced which shows a bifurcation in the development of MARFE instability.
A New Method for Diagnosing the Temperature Profile in an Axisymmetric Plasma
WANG Weifeng, XU Xueji
Chin. Phys. Lett. 1995, 12 (3): 171-174 .  
Abstract   PDF(pc) (194KB) ( 402 )
A relative spectroscopic method employing two spectral lines is developed to determine the radial temperature profile in an axisymmetric plasma discharge. The method is independent of the well-known Abel-inversion and of gas pressure if optically-thin lines are used, and also has no restriction on the presumption of the temperature profile such as the Bartels'approximation, i. e., the parabola. The high efficiency of the technique is tested by its application to a dielectric barrier gas discharge. The discharge configuration is an enclosed cylindrical and annular gap filled with Hg-Ar mixture.
Molecular Short Range Correlations in Nematic Liquid Crystal Films
ZHANG Zhidong, YANG Guochen
Chin. Phys. Lett. 1995, 12 (3): 175-178 .  
Abstract   PDF(pc) (146KB) ( 434 )
A generalized functional variation theory of nematics is presented to take account of the local short range correlations between molecules. This theory is used to study nematics liquid crystal films. The nematics-isotropic transition temperature is determined. The orientational order parameter in each molecular layer and the internal energy per molecule associated with each layer are calculated. The numerical results are compared with those of the Monte Carlo simulation and of the mean field theory.
A New Method to Predict Critical Temperature of the Ising Model by Extrapolating Variational Cumulant Expansion to Infinite Order
LIU Ruijie, CHEN Tianlun, ZHAO Bojuan*
Chin. Phys. Lett. 1995, 12 (3): 179-182 .  
Abstract   PDF(pc) (177KB) ( 520 )
The critical temperatures of the Ising model in square and simple cubic lattices are derived with the variational-cumulant expansion approach to the seventh order. An extrapolating method is proposed to predict the critical temperature of infinite series according to the finite order expansion, at which a weighted fitting method is used. For the 2-dimensional Ising model, the critical temperature obtained by this method is in a deviation of 0.04% compared with the exact value, and the estimated results are robust for different order prediction. The critical temperature for the 3D Ising model is predicted as 4.490.
A General Theory of Coupled Linear-Response of Inhomogeneous Media
NAN Cewen
Chin. Phys. Lett. 1995, 12 (3): 183-185 .  
Abstract   PDF(pc) (139KB) ( 333 )
A generally exact theory for predicting the effective behavior of coupled linear-response for inhomogeneous media is developed. The theory can not only give the general results of the effective principal and coupled moduli for the coupled multifield problems, but also provide the interrelationships between these effective moduli. It can be directly employed to describe the coupled two-field or three-field response of any inhomogeneous media.
On the Spatial Configuration of the Mitotic Spindle
WEN Weijia, SUN Limin, LU Kunquan, TANG Xiaowei*
Chin. Phys. Lett. 1995, 12 (3): 186-188 .  
Abstract   PDF(pc) (222KB) ( 436 )
An experimental simulation using electrorheological (ER) fluid is developed to investigate the spatial configuration of the mitotic spindle. In the presence of two different kinds of electric field, the structures of particle arrangement in ER fluid are similar to the configuration of the mitotic spindle of the animal and plant cells respectively.
Radio Radiation Mechanism of Two-Streams Plasma in the Astrophysical Jet
LU Shengzhi, TONG Yi, SU Yang
Chin. Phys. Lett. 1995, 12 (3): 189-192 .  
Abstract   PDF(pc) (200KB) ( 408 )
To explain the radio mechanism of non-relativistic jets, we investigate a nonlinear process in which ion-acoustic waves scatter into high frequency electromagnetic waves by the plasma having a non-Maxwell distribution with non-relativisical energetic electrons. The calculated reaults show that this mechanism is efficient, and may apply to the radiation of jets from active galaxies and radio bursts of sun flares.
17 articles