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Volume 8 Issue 3
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Original Articles
Classical Limits of Distribution Functions for Stationary Systems
HUANG Xiangyou
Chin. Phys. Lett. 1991, 8 (3): 110-113 .  
Abstract   PDF(pc) (161KB) ( 528 )
Homogeneous ensembles are introduced and their distribution functions in phase space are given. A comparison between these distribution functions and those obtained from quantum stationary systems is made. It is shown that the quantum stationary systems are completely equivalent to homogeneous ensembles in the classical limit.
Solutions of Dirac Equation with One-Dimensional Scalarlike Potential
SU Rukeng, ZHONG Yu, HU Sizhu
Chin. Phys. Lett. 1991, 8 (3): 114-117 .  
Abstract   PDF(pc) (172KB) ( 513 )
After introducing an unitary transformation to decouple the correlations of the different components of the Dirace equation, we found the exact solutions of the Dirace equation with a finite size linear scalarlike potential analytically. The transmission amplitude and the reflection amplitude are given.
On Black Hole Thermodynamics and Back-reaction
HUANG Chaoguang, LIU Liao, XU Feng
Chin. Phys. Lett. 1991, 8 (3): 118-121 .  
Abstract   PDF(pc) (179KB) ( 394 )
It is shown in this paper that there is a difficulty in conventional black hole thermodynamics. To overcome the difficulty we introduce a “surface” near the event horizon as an additional thermodynamical object. The mass and entropy of the additional “surface” are the same as the correction of mass of Schwarzschild black hole obtained in the back-reaction program up to a constant factor. This implies that some effects of back reaction an automatically considered in our thermodynamic phenomenological treatment.
Decay Z→π0γ in the Standard Model
HUANG Chaoshang
Chin. Phys. Lett. 1991, 8 (3): 122-124 .  
Abstract   PDF(pc) (112KB) ( 358 )
The decay Z→π0γ, for which a recent study found a sizable rate, is examined. It is shown that the rate for Z→π0γ is calculatable in the standard model and the result of a calculation shows that the rate is much suppressed.
One-Meson Exchange in Quantized Two-Breather Model
YANG Keyan
Chin. Phys. Lett. 1991, 8 (3): 125-128 .  
Abstract   PDF(pc) (165KB) ( 390 )
Instead of two-kink system, two-breather system under sum ansatz is quantized. A covariant meson-breather interaction to the one-meson range and to the leading nonstatic order is obtained. All of the results depend on breather internal variable θ .
Electronic Structures of Molecular Rydberg States for Diatomic Molecules
LIU Lei, LI Jiaming
Chin. Phys. Lett. 1991, 8 (3): 129-132 .  
Abstract   PDF(pc) (222KB) ( 534 )
We present our theoretical study in electronic structures of molecular Rydberg states for some diatomic molecules along the second row in the periodic table which involve binding between atomic 2s and 2p valence orbitals.
Emission Spectrum of Zn2 Excimers
YANG Yongwu, CHENG Bingying, LI Zhaolin, NIE Qingxiang, ZHANG Daozhong
Chin. Phys. Lett. 1991, 8 (3): 133-136 .  
Abstract   PDF(pc) (206KB) ( 459 )
Under laser excitation of vaporized zinc to 4s4p 3P01 metastable level, the emission bands at violet and ultraviolet ranges were observed. The radiative decay time of 20 ns has been measured for both bands. The temporal behavior and excitation condition indicate that they are possibly from the same state 3Σ+u of Zn2 molecule. The wavelength range of the two bands coincides with theoretical predication.
A Universal Value for the Charge-Transfer States of Different Alkali-Halide Molecules
GONG shangqing, PAN Shaohua
Chin. Phys. Lett. 1991, 8 (3): 137-140 .  
Abstract   PDF(pc) (184KB) ( 359 )
The scaled potentials were used to discuss the vibrational quantum defects of alkali-halide molecules by using the fully quantal Milne equation method and the quasiclassical Wentzell-Kramers-Briilouin approximation. This allowed us to obtain a universal function and its limit value for the charge-transfer states of different alkali-halide molecules.
Rabi Sidebands of Dressed Na Atom Excited By a Pulsed laser
CHEN Tianjie, DUAN Shaoguang
Chin. Phys. Lett. 1991, 8 (3): 141-144 .  
Abstract   PDF(pc) (192KB) ( 411 )
The observation of Rabi sideband of Na atom shows the two-level dressed atom model is over simplified. Using a multi-level model and considering the time evolution of the laser pulse the experiment is well explained.
Photoacoustic Chopping Frequency Response to X-ray Absorption
XIAO Guangming, HUANG Yuying, JIANG Donghong, XIAN Dingchang
Chin. Phys. Lett. 1991, 8 (3): 145-148 .  
Abstract   PDF(pc) (212KB) ( 496 )
Photoacoustic (PA) effect induced in solids by X-ray absorption was observed, and the experimental signals were obtained on graphite and copper samples as functions of the chopping frequency. Theoretical calculations and detailed discussions were made to interpret the experimental results using Rosencwaig-Gerho (RG) theory.
Implantation Energy Selection in Molecular-Beam Epitaxy GaAs Films on Si Substrates
XIAO Guangming*, YIN Shiduan*, ZHANG Jingping*, DING Aiju, DONG Aihua, ZHU Peiran, ZHOU Junming, LIU Jiarui
Chin. Phys. Lett. 1991, 8 (3): 149-152 .  
Abstract   PDF(pc) (197KB) ( 439 )
GaAs films made by molecular beam epitaxy with thicknesses ranging from 0.9 to 1.25μm on Si have been implanted with Si ions at 1.2MeV to dose of 1x1015/cm2. A rapid infrared thermal annealing and white light annealing were then used for recrystallization. Crystalline quality was analysed by using backscattering channeling technique with Li ion beam of 4.2MeV. The experimental result show that energy selection is important for obtaining better and uniform recrystallized GaAs epilayers.
Elastic Constants of Nickel Oxide
WANG Jifang, FISHER, E. S., M. H. Manghnzmi
Chin. Phys. Lett. 1991, 8 (3): 153-156 .  
Abstract   PDF(pc) (228KB) ( 556 )
Previous measurements of the single crystal elastic constants of NiO by ultrasonic techniques have been in wide disagreement. This paper gives the results of recent data obtained from several well characterized NiO single crystals. The present results for the antiferromagnetic phase at 298K are different from the previous data and rectify certain questions about the elastic anisotropy ratio C44/C' and bulk modulus Ks.

Ar Ion Implantation Induced Tc Degradation of YBa2Cu3O7-x Thin Films
LI Yijie, REN Congxin, CHEN Guoliang, LIN Zixin, ZOU Shichang
Chin. Phys. Lett. 1991, 8 (3): 157-160 .  
Abstract   PDF(pc) (203KB) ( 438 )
The Ar ion implantation induced changes of structure and transport properties of YBa2Cu3O7-x thin films were studied as a function of fluence. Both the zero resistance temperature Tc and the critical current density Jc decrease rapidly with fluence, however, the transition temperature onset almost remains constant at low fluences. At dose of 1.2x1013Ar/cm2, the sample has a metal to semiconductor phase transition. When the fluence further increases, a crystalline to amorphous phase transition occurs, and the sample becomes insulator.

Optical Gap and Transport Properties of Sb-Doped SnO2 Films
WANG Wanlu
Chin. Phys. Lett. 1991, 8 (3): 161-164 .  
Abstract   PDF(pc) (212KB) ( 423 )
In this work we measured Hall effect and thermoelectric power as well as transmission and reflection spectra in the visible and near-infrared (IR) regions, and calculated the optical gap energy for Sb-doped SnO2 films grown on 7059 glass substrate by chemical spray technique. Experimental results show that the optical gap energy increases with increasing annealing temperature, and the effective mass m* in relation to the free-electron mass m0 for a given carrier concentration n and scattering parameter p is also given.
14 articles