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Volume 9 Issue 4
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Original Articles
Vertex Decoupling and Quark Deconfinement in Soliton Bag Model at Finite Temperature
SU Rukeng, ZHENG Guotong*
Chin. Phys. Lett. 1992, 9 (4): 169-172 .  
Abstract   PDF(pc) (159KB) ( 496 )
By means of the Matsubara Green’s function method, we investigate the tem-perature dependence of coupling constant gqqo in soliton bag model. We find gqqσ will decrease as temperature increases in high temperature region and will approach zero at critical temperature Tc. The quark deconfinement phase transition in soliton bag model is discussed.
Nuclear Shadowing in Very Small Bjorken Variable Region
FU Xinyong, ZHU Wei*
Chin. Phys. Lett. 1992, 9 (4): 173-175 .  
Abstract   PDF(pc) (138KB) ( 396 )
We show that partonic shadowing model can be used to describe the nuclear shadowing phenomena of Q2>1 GeV2. The shadowing saturation observed in E665 experiment in very small Bjorken variable region is originated from the interaction between the component of vector meson in the probe r* and the nuclear target while Q2<0.1 GeV2.
Measurement of N in High Z Substrate Using Non-Rutherford Backscattering
DING Furong, DU Shekui, DONG Weizhong
Chin. Phys. Lett. 1992, 9 (4): 176-179 .  
Abstract   PDF(pc) (186KB) ( 508 )
The relative cross sections of Non-Rutherford backscattering of He ions from N atoms at the energy range of 2-5 MeV were measured. Several resonance energies and corresponding resonance widths are tabled. For analysis of N in high Z substrate, the results of both experiment and computer simulation rvere given in this report.
First Performance Test at BEPC X-Ray Absorption Fine Structure Station
QIAO Shan, HA Yang, XIE Yaning, HU Tiandou
Chin. Phys. Lett. 1992, 9 (4): 180-182 .  
Abstract   PDF(pc) (141KB) ( 412 )
The foundation of the first synchrotron radiation x-ray absorption fine structure (XAFS) station in China has been completed and the station was ready for transmission XAFS experiment. This paper reports the first XAFS spectrum recorded in this station and the result of performance test centered on the intensity, energy dispersion and energy accuracy of the beam line in this station.
A New Turbulent Collision Integral in Plasma Kinetic Equation
HU Xiwei
Chin. Phys. Lett. 1992, 9 (4): 183-186 .  
Abstract   PDF(pc) (142KB) ( 416 )
A new turbulent collision integral is derived from the first and second BBGKY equations, in which the effects of well-developed turbulent field are taken into account. The turbulent collision integral contains turbulent frequency-wave number spectrum and up to fourth order differential of particle distribution function.
Slab Model Analysis of Motion for a Charged Particle with Large Larmor Radius in Tokamak magnetic Field
YU Junsheng
Chin. Phys. Lett. 1992, 9 (4): 187-190 .  
Abstract   PDF(pc) (177KB) ( 421 )
The motion of a charged particle in tokamak magnetic field whose Larmor radius ρ0 is not much smaller than the typical length LB is studied in slab model by solving the equations of motion analytically, where LB=|B/ΔB|. It is found that drift can still be predicted by the drift approximation, but gyration depends largely on the variation of the magnetic field over Larmor radius and the initial motion parameters. In the case of ρ0/ LB<<1, our results show their agreements with the previous work.
Image Intensity Inversion Operation Using KNSBN:Cu Crystal Self-Pumped Phase-Conjugator
XU Jingjun, ZHANG Guangyin, LIU Simin, WU Yuanqing, SUN Daliang*, SONG Yongyuan*, CHEN Huanchu*
Chin. Phys. Lett. 1992, 9 (4): 191-193 .  
Abstract   PDF(pc) (154KB) ( 442 )
The image intensity inversion operation was succeeded by using the new type KNSBN:Cu crystal self-pumped phase-conjugate mirror. The new phase-conjugator was demonstrated to have the reguired specifications for this optical processing application.
Transformation of Graphite to Diamond by Bombardment of Intense Pulsed Electron Beams
HAN Lijun*, JIANG Xingliu
Chin. Phys. Lett. 1992, 9 (4): 194-197 .  
Abstract   PDF(pc) (292KB) ( 521 )
When intense pulsed electron beam bombards a cold graphite target, energy and momentum transfer from electrons to graphite cause the latter to be heated and a shock pressure to be set up within the target. The direct conversion of graphite to diamond particle has been accomplished by using this method. The studies of scanning electron microscopy and Raman spectroscopy prove such a transformation.
Electronic Structure of (111)-Oriented Strained-Layer SiGe Superlattice
GU Binglin, DUAN Wenhui, ZHU Jialin, WANG Mingliang*
Chin. Phys. Lett. 1992, 9 (4): 198-201 .  
Abstract   PDF(pc) (249KB) ( 822 )
Using the first-principle self-consistent linear-muffin-tin-orbital method within the local density approximation, band structure of (111)-oriented strained-layer SiGe superlattice is studied. Three different ordered arrangements of atom layers (Si-GeΞSi-Ge Si-SiΞ Ge-Ge and SiΞSi-GeΞGe) are considered. Calcu- lated results indicate that (111)-oriented SiGe strained layer superlattices are semiconductive, with a band gap about 1.0eV. The first two superlattices are indirect band gap semiconductors, and the third one (SiΞSi-GeΞ Ge) is a direct band gap semiconductor. The influence of strain on the band structure is also investigated.

Effects of Magnetic Fields on Exciton Binding Energy in a Quantum Well
HUANG Xiaowu, HAN Jiahua, Qian Kaiyi, LI Zhongyong
Chin. Phys. Lett. 1992, 9 (4): 202-205 .  
Abstract   PDF(pc) (154KB) ( 448 )
The shift of the exciton peak in a GaAs/Ga1-xAlxAs multiple quantum well is calculated as a function of magnetic fields. We adopt a variational wave function and calculate the energy of two dimensional exciton. As expected, the theoretical results fit the experimental values.
Thermally Activated Flux Motion in 2223 Phase High Temperature Superconductors
CHEN Jun, LI Gang, LI Chuanyi, FENG Qingrong, ZHANG Han, FENG Xiaoqi, ZHU Xing, YIN Daole
Chin. Phys. Lett. 1992, 9 (4): 206-208 .  
Abstract   PDF(pc) (169KB) ( 441 )
Isothermal V-I characteristics of Bi1.8Pb0.2Sr2Ca2Cu3Oy high temperature superconductors (HTSCs) have been systematically studied. Below the irre-versibility temperature Tr(H), two important features were observed: 1) Both positive and negative curvatures can coexist in the same isothermal V-I curve, so it is different from the scaling behavior V∝exp(-(J0/J)μ). 2) The activa-ion volume of flux motion is found temperature dependent as (1=T/Tr(H))-2v with v about 0.5. This behavior supports the existence of a two-dimensional secondary phase transition below Hc2(T) in this Bi-based HTSCs.

Magnetoresistance in FeSi/Cu Compositionally Modulated Films
LUAN Kaizheng, LIU Yihua, MA Xiaoding
Chin. Phys. Lett. 1992, 9 (4): 209-212 .  
Abstract   PDF(pc) (247KB) ( 425 )
FeSi/Cu compositionally modulated amorphous films with different thicknesses of Cu layers have been obtained by radio-frequency sputtering. We studied the resistivity and magnetoresistance of these samples at room temperature. The resistivity of FeSi/Cu compositionally modulated films (CMFs) increases with decreasing the thickness of Cu layers. The FeSi/Cu CMFs show a negative magnetoresistance effect. The magnetoresistance decreases with decreasing the Cu layer thickness d, when dc, is over 20Å, but it turns to increase with decreasing dc, when dc, is below 20Å. This is probably caused by the polarization of conductive electrons of Cu.
Determination of Photoelastic Constant Ratio of the Two Components in GexSi1-x/Si Superlattice
JIN Ying, ZHANG Shulin, ZHOU Guoliang*, YU Mingren*, QIN Guogang***
Chin. Phys. Lett. 1992, 9 (4): 213-216 .  
Abstract   PDF(pc) (226KB) ( 451 )
From the intensity ratio of the folded longitudinal acoustic phonons with re-spect to the longitudinal acoustic phonon in a Ge0.51Si0.49/Si superlattice (SL),we obtained a photoelastic constant. ratio of 6.6 for Ge0.51Si0.49 alloy with re-spect to Si in the SL at wavelength 5145Å, which is 2.6 times greater than that obtainedby [He Phys.Rev. B39(1989) 5919] in a Ge0.51Si0.49/Si SL.
Physisorption of Nitrogen on Grafoil Studied by Doppler Broadening Measurement
LIU Hao, LIN Dong, WANG Shaojie(S. J. Wang)
Chin. Phys. Lett. 1992, 9 (4): 217-220 .  
Abstract   PDF(pc) (196KB) ( 482 )
Positron Annihilation Spectroscopy has been applied to study the physisorption of nitrogen on graphite surface. The Doppler broadening spectra have been measured as a function of the fractional monolayer coverage. The Doppler broadening S-parameter has a maximum at half monolayer. It is interpreted as a result of structural inhomogeneity (defect-type) created by the presence of nitrogen molecules on the graphite surface.
Multiple Production of Bianchi Type-I Universes
TAO Caide, WANG Wenfu+
Chin. Phys. Lett. 1992, 9 (4): 221-224 .  
Abstract   PDF(pc) (179KB) ( 403 )
The procedure similar to an ordinary quantum field theory in curved spacetime is applied to study the Bianchi type-I universes with a radiation field source. The Wheeler-De Witt equation satisfied by the cosmological wave function is found. After the wave function was regarded as a universe field in
the minisuperspace, not only the difficulty in a probabilistic interpretation in the quantum cosmology can be circumvented, but also the conclusion of the multiple production of universes is obtained, and the average number of various universes created from 'nothing' is estimated.

15 articles