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Volume 12 Issue 12
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Original Articles
Physical Mechanism of Neutron Halo on Drip Line Light Nuclei
WANG Zhengda, ZHANG Xiaodong, WANG Xiaochun, WANG Xiaobin
Chin. Phys. Lett. 1995, 12 (12): 705-708 .  
Abstract   PDF(pc) (0KB) ( 224 )
In order to extend the conventional shell model calculation with harmonic oscillator bases to halo nuclei a self-similar-structure shell model (SSM) in which the single particle orbit has state(orbit)-dependent frequency was proposed. We do this by a rescaling of both the kinetic and potential energy term of the harmonic oscillator and a mean field imitation so that the physical mechanisms of both neutron skin and neutron halo as well as the bound state properties of Borromean nuclei such as 6He, 11Li and 14Be can be revealed in SSM.
Mechanism of Variance of Moment of Inertia in Fermion Dynamical Symmetry Model
DI Yaomin
Chin. Phys. Lett. 1995, 12 (12): 709-712 .  
Abstract   PDF(pc) (191KB) ( 449 )
The mechanism of variance of moment of inertia in the fermion dynamical symmetry model is investigated. It is shown that the heritage mixing is indeed the major factor causing the variance of moment of inertia in well-deformed nuclei, but the scheme of the mixing and the form of heritage mixing interaction are important to describing the phenomenon.
Autoionizing Process of the Double Rydberg State
XU Chengbin, XU Xiangyuan, HUANG Wen*, XUE Ping, ZHAO Runchuan, ZHU Cheng, CHEN Dieyan
Chin. Phys. Lett. 1995, 12 (12): 713-716 .  
Abstract   PDF(pc) (202KB) ( 417 )
Using five-laser resonance excitation and double time-of-flight spectroscopy, the double Rydberg states NLnl (N ≤ 66; n ≤ 85; L, 1 < 4) of Ca have been obtained. The distribution of Ca+ Rydberg states, which is from the autoionization of the double Rydberg state has been measured. A novel result has been observed.
Photoluminescence Study of C70 Film Manufactured by Physical Jet Deposition
WANG Derong, KE Guoqing, QIAN Shixiong, PENG Wenji*, YU Zhenxin*
Chin. Phys. Lett. 1995, 12 (12): 717-719 .  
Abstract   PDF(pc) (185KB) ( 617 )
We have fabricated C70 film by physical jet deposition (PJD) technique and measured the absorption and photoluminescence (PL) spectra of this End C70 film. In comparison with the deposited C70 film in high vacuum, the absorption and integrated PL spectra are similar, but there is a big difference in the time-resolved PL. The C70 film made by PJD shows a very fast PL decay of less than 20ps which should result from the fast relaxation process of C70 molecule in the excited state S1 of this new kind film.

Compression Effect of Ultrashort Pulse in Far Infrared Waveguide Free Electron Laser
HU Suxing, FU Ensheng
Chin. Phys. Lett. 1995, 12 (12): 720-723 .  
Abstract   PDF(pc) (223KB) ( 472 )
Compression mechanism of ultrashort pulse in far infrared waveguide free electron laser driven by radio frequency linear accelerator was investigated. With a pertinent waveguide gap b, when the original phase velocity of the electron bunch ensures the positive gain and the refractivity of the optical pulse monotone increasing along the dative slip distance, the longitudinal length of optical pulse will be continuously shortened so that the pulse power increases quickly until saturation occurs. To offset the "lethargy" effect, an optimal cavity detuning ΔLc has been accurately determined.
A New Way to Observe Chaos and Self-Pulsings in Class B Lasers
LUO Liguo
Chin. Phys. Lett. 1995, 12 (12): 724-727 .  
Abstract   PDF(pc) (156KB) ( 463 )
A dual-coupled class B laser system was proposed to observe self-pulsings and chaos behaviours. The system gives cw, self-pulsing and chaos outputs. Period doubling route to chaos was found in the system.
Quantum Zeno Effect Induced by Quantum Measurement of Momentum of Atomic Mass Center
WANG Xiaoguang
Chin. Phys. Lett. 1995, 12 (12): 728-730 .  
Abstract   PDF(pc) (130KB) ( 408 )
In this article, we obtained the factorization form of the evolution operator corresponding to the Hamiltonian which describes the interaction of a two-level atom with one propagating mode in an optical ring cavity and the exact solution is followed. A new scheme for realizing quantum Zeno effect is proposed by measuring the atomic momentum (external state) frequently to freeze the atomic energy state (internal state) in its initial energy state.
Transverse Modulation of a Laser Beam in Cerium-Doped BaTiO3
XIE Ping, DAI Jianhua. WANG Pengye, ZHANG Hongjun
Chin. Phys. Lett. 1995, 12 (12): 731-734 .  
Abstract   PDF(pc) (222KB) ( 418 )
An extraordinarily polarized Gaussian beam, after passing through a photorefractive crystal with an external electric field, shows transverse spatial modulation and self-focusing due to the in-phase component of the refractive index change relative to the intensity profile of the beam. Besides that the beam shifts toward the Crystal c-axis due to the π / 2 out-of-phase component.
Large Stable Photoinduced Anisotropy and Optical Information Storage in Poly [4-bis (N, N-oxyethylene) imino-4- nitroasobenzene Succinyl] Film by Two-Wave Mixing
WEI Xiong, YAN Xingzhong, LIN Weizhu, MO Dang, LIANG Zhaoxi
Chin. Phys. Lett. 1995, 12 (12): 735-738 .  
Abstract   PDF(pc) (232KB) ( 403 )
Optical information storage caused by photoinduced anisotropy in poly [4'-bis (N, N-oxyethylene) imino-4-nitroazobenzene succinyl] film is studied by two-wave mixing. Using Nd:YAG second-harmonic pulses (100ps), grating of orientation of azobenzene molecules is formed in the film by photoinduced anisotropy. Up to third-order diffraction was observed. After turning off one of the two pump lights, the signals remained. When the weaker one of two pump lights was turned off, the intensities of diffraction beams of another pump light almost did not decrease. The information recorded in the film can be 100% maintained for a long time (monitored over 100 days without obvious decrease).

Fractal Nature of Capillary and Viscous Fingering in Two-Dimensional Porous Media
TIAN Juping, YU Boming, YAO Kailun*
Chin. Phys. Lett. 1995, 12 (12): 739-742 .  
Abstract   PDF(pc) (196KB) ( 554 )
A computer model of capillary and viscous fingering in a porous media is presented, which treats the media as a square lattice connected with randomly chosen radius. The fractal properties of the model are studied for shell-shell aggregation method by Monte Carlo simulation. The simulation results show that the dimension D increases along with increasing of M and decreasing of μ, where M and μ are the ratios of the viscosity of the two fluids and the most probable radius of the throat in porous media respectively. It is found that there exist four regions for fluid.
A Hybrid Dissipative Trapped Electron ITG Mode
BAI Lin(L. Bai), QIU Xiaoming(X. M. Qiu), HUANG Lin(L. Huang)
Chin. Phys. Lett. 1995, 12 (12): 743-746 .  
Abstract   PDF(pc) (204KB) ( 375 )
A simple model for the ηi-mode taking account of the dissipative trapped electron effect, which is described by means of the well-known formula of the nonadiabatic electron response, in a sheared slab geometry is presented. It predicts the existence of a hybrid dissipative trapped electron ion temperature gradient (ITG) mode. This conclusion is in agreement with the observation in the latest simulated tokamak experiment on the Columbia Linear Machine.
Theory of Resistivity-Gradient-Driven Turbulence in the Presence of Flow
PENG Xiaodong, ZHANG Jinhua, GAO Qingdi
Chin. Phys. Lett. 1995, 12 (12): 747-750 .  
Abstract   PDF(pc) (200KB) ( 409 )
The resistivity-gradient-driven turbulence is investigated in the presence of both poloidal and parallel/toroidal flows. At saturation, the poloidal flow shear reduces fluctuations at the edge of plasmas, the parallel flow and its shear both reduce fluctuations in the core of plasmas. This indicates that the mechanism for a high confinement regime (H mode) may be the turbulence suppression due to the poloidal flow shear at the edge of plasmas, and the mechanism for a very high confinement (VH mode) may be the turbulence suppression due to the toroidal flow and its shear in the core of plasmas.
Molecular Dynamics Simulation of Low-Energy C60 in Collision with a Graphite (0001) Surface
MAN Zhenyong, PAN Zhengying, LIU Lei, LI Rongwu
Chin. Phys. Lett. 1995, 12 (12): 751-754 .  
Abstract   PDF(pc) (223KB) ( 517 )
The collision of C60 with a graphite (0001) surface has been investigated by molecular dynamics simulation with TLHL potential. At an impact energy of 90eV, the C60 buckyball first deformed to a disc-like structure and then transformed back to its original shape and recoiled slowly. No dissociation of the C60 was observed on the time scale of the simulation. Unlike a single-atom-surface collision, the C60 -surface interaction is a highly inelastic process.
Random-Like Deposition Model of Surface Growth Kinetics
WANG Wei, Hilda A. Cerdeira*
Chin. Phys. Lett. 1995, 12 (12): 755-758 .  
Abstract   PDF(pc) (232KB) ( 451 )
The surface growth kinetics of random-like deposition model with two kinds of particles (A and C) is studied. The scaling behavior of the surface width is obtained for various deposition probabilities of particle C and system sizes. We also found a change of different morphologic structures which results from the diffusion of particle C.
A Study of 90° Ferroelectric Domain Structures in PbTiO3 Thin Films by Means of Transmission Electron Microscopy
MA Wenhui, LI Qi, CHEN Yanfeng, YU Tao, SHUN Li, MIN Naiben
Chin. Phys. Lett. 1995, 12 (12): 759-762 .  
Abstract   PDF(pc) (233KB) ( 450 )
PbTiO3 thin films prepared by metalorganic chemical vapor deposition method were investigated using a transmission electron microscope. The as-deposited thin films were highly c-axis oriented, 90°a-c domains were observed And their crystallographic characteristics were investigated. Tetragonality of the PbTiO3 films was also obtained. The disappearance of 90°domains in the very thin film was found and attributed to surface relaxation effect.
Time Domain Spectroscopy Function and Line Shape of Slow Responses
LI Jingde, TANG Xingui, FAN Yangcai*, ZHOU Zhenhong*
Chin. Phys. Lett. 1995, 12 (12): 763-765 .  
Abstract   PDF(pc) (127KB) ( 447 )
The spectroscopy function and line shape of slow responses are defined in time domain. In dielectric and piezoelectric relaxations experimental results show that this method has high resolution.
Inflation with Conformally Coupled Scalar Field
WANG Wenfu
Chin. Phys. Lett. 1995, 12 (12): 766-768 .  
Abstract   PDF(pc) (122KB) ( 488 )
In a Robertson-Walker geometry conformally coupled to a scalar field with inflation potential V() = M4- (1/4)λ4, we investigate the classical evolution of a universe. The exact solutions in the model have been found. It is shown that in the region where the value of the p field is 0 <  < max, (max is the solution of V() = 0), there is inflation. This model can lead to successful inflation with λ ~ 10-9, rather than 10-13as previously reported.

17 articles