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Volume 9 Issue 6
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Original Articles
Numerical Study on Fokker-Planck Equation of Bistable System Driven by Colored Noise
LU Zhiheng, HU Gang*, L.Schoendorff**, H.Risken**
Chin. Phys. Lett. 1992, 9 (6): 281-284 .  
Abstract   PDF(pc) (231KB) ( 417 )
A finite difference method is used to solve a Fokker-Planck equation of bistable system with Landau potential. The detailed dynamical relaxation process in the case of large correlation time is manifested via the phenomena including the saddle point appearance, the hole formation and distortion. The method is used to obtain the stationary solutions of Fokker-Planck equation of bistable system driven by rather weak noise.
Solution of Salpeter Equation for 0- Mesons Involving the Vacuum Condensates in Quantum Chromodynamics
BIAN Jianguo, HUANG Tao
Chin. Phys. Lett. 1992, 9 (6): 285-288 .  
Abstract   PDF(pc) (170KB) ( 815 )
We study the solutions of the salpeter equation for 0- mesons of equal mass quark-antiquark. A potential which was derived in our previour paper in quantum chromodynamics in the background fields is used as the kernel. It includes the perturbative interaction of one gluon exchange and the nonperturbative corrections induced by the quark condensate and the gluon condensate. The results for mπ mηc and mηb are quite reasonable.

Virtual Gluino Correction to the Decay Z → bb
LI Chongsheng, HU Bingquan
Chin. Phys. Lett. 1992, 9 (6): 289-292 .  
Abstract   PDF(pc) (166KB) ( 357 )
We computed the O(αs) virtual gluino correction to the process Z → bb in the minimal supersymmetric standard model, and investigated the dependence of the process on gluino and squark masses. For some values of masses, the correction implies about 7%-12% additional decrease of the ratio Γ(Z → bb)/ Γ (Z → hadrons) relative to the standard model expectation.

CHHE-MRT Method for Three-Body Problem
LI Shiqing, XU Dingan, JIAO Shuqing*, LIU Fuqing
Chin. Phys. Lett. 1992, 9 (6): 293-296 .  
Abstract   PDF(pc) (170KB) ( 382 )
Continuum hyperspherical harmonics expansion momentum representation transformation (CHHE-MRT) method for three-body problem is briefly introduced, including two-body T matrix and hyperradial function of three-body in bound state or in scattering state. As a check of this method, the binding energies and hyperradial functions in bound states of 3N(3H) and 3α (12C) systems are calculated by using Gauss, exponential and Yukawa potentials, respectively.

Fragment Anisotropy of Complete Fusion-Fission at Subbarrier Energies for the 11B+238U and 12C+237Np Reactions
ZHANG Huanqiao, LIU Zuhua, XU Jincheng, QIAN Xing, CHEN Shaolin, LU Lixing
Chin. Phys. Lett. 1992, 9 (6): 297-300 .  
Abstract   PDF(pc) (247KB) ( 564 )
Fission fragment angular distributions have been measured for the reactions 11B+238U, 12C+237Np at near- and sub-barrier energies, and 16O+238U at 90MeV. The complete fusion-fission and transfer-fission were separated as components in the whole energy region in this experiment. The influence of pre-scission neutron emission on fragment anisotropies has been considered. This effect leads to increase of the anisotropies when compared with the results obtained under the assumption of first chance fission. However, the anomalous anisotropies still persist.
Direct Atomic Images of Dislocation Motion Caused by Image Force near Surfaces of Pd Crystal
YE Hengqiang, NING Xiaoguang, D. J. Smith*
Chin. Phys. Lett. 1992, 9 (6): 301-304 .  
Abstract   PDF(pc) (219KB) ( 537 )
The motion of a Lomer dislocation near clean (1ī0) surface of the Pd metal was observed in situ at the atomic level by surface profile imaging technique. The observed distances between the location of the Lomer dislocation and the surface was just covered by the calculated critical range l, within which the image force alone may become the cause of dislocation.
First Principle Self-Consistent Pseudopotential Calculation on the Electronic Structure of (InAs)1(GaAs)1 Superlattice
FAN Weijun*, GU Zongquan**, XIA Jianbai*
Chin. Phys. Lett. 1992, 9 (6): 305-308 .  
Abstract   PDF(pc) (198KB) ( 573 )
The band structure of the (InAs)1(GaAs)1 strained superlattice is calculated by the self-consistent pseudopotential method. The results show that the (InAs)1(GaAs)1 is a direct-gap superlattice. With the local density approximation, the band gap calculated with the room temperature lattice constants is 0.43eV, and the corrected value is 0.91eV, in agreement with experimental results. Because of the lattice mismatch between InAs. and GaAs layers, the three-fold degenerate energy level at the top of valence band splits into two levels with a spacing of 0.29eV. The splitting of energy level is also estimated and explained using the effective-mass theory.

Soliton in Deformable Three-Dimensional Electron-Phonon System
Chin. Phys. Lett. 1992, 9 (6): 309-312 .  
Abstract   PDF(pc) (178KB) ( 415 )
As the electron moves in deformable three-dimensional continuous medium, it is not only affected by phonons but also affected by deformable potential. It is found that when the motion of electron is in the direction of non-deformation, it is plane wave, but it is soliton wave in the direction of deformation.

Electronic Wave Functions and Subband Energies in Superlattice with a Complex Basis
SHI Junjie*, PAN Shaohua**
Chin. Phys. Lett. 1992, 9 (6): 313-316 .  
Abstract   PDF(pc) (140KB) ( 457 )
Electronic wave functions and energies in superlattice with a complex basis have been obtained that are more general than those of Pan et al. [Phys. Rev. B 44 (1991) 5668]. This paper gives not only subbands but also wave functions for all values of the wave number for superlattice with a complex basis.
Adsorption of Oxygen on KxC60 Studied by Photoelectron Spectroscopy
YAO Jun, LIU Fengqin, DENG Junzhuo, XUN Kun, WANG Zuquan, LÜ, Sihua, WU Sicheng, JIANG Mingluo, GU Zhengnan, ZHOU Xihuang
Chin. Phys. Lett. 1992, 9 (6): 317-320 .  
Abstract   PDF(pc) (235KB) ( 381 )
Photoemission spectra of vacuum deposited K-incorporated C60–KxC60( x≈6 ) , before and after exposure to oxygen, show that the interaction between oxygen and potassium forms an overlayer of 40Å K-O complex with stoichiometry near to that of potassium peroxide K2O2 on the surface. In contrary to the oxidation of potassium film, no potassium oxide K2O has been observed.
X-ray and Nuclear Magnetic Resonance Study of Mechanical Alloying of Cu59-Zr41 Mixed Powders
LI Baiqin, XIAO Keqin*
Chin. Phys. Lett. 1992, 9 (6): 321-324 .  
Abstract   PDF(pc) (269KB) ( 400 )
63Cu nuclear magnetic resonance investigation, together with x-ray diffraction, of the mixed Cu59-Zr41 powders during mechanical alloying is reported. The results show that the s-electron density of states at Fermi surface is reduced and polarization effects exist during alloying. It is concluded that amorphization or more generally true alloying reaction has taken place by ball-milling through the strong interaction between copper and zirconium powders in the mixtures within atomic scale.
Refractive indices of GaInAsSb Quaternary Alloys Grown by Molecular Beam Epitaxy
BI Wengang, LI Aizhen
Chin. Phys. Lett. 1992, 9 (6): 325-328 .  
Abstract   PDF(pc) (173KB) ( 518 )
The refractive indices of molecular beam epitaxy grown GaInAsSb quaternary alloys on semi-insulating GaAs substrates have been determined by Fourier transform infrared spectroscopy measurement at room temperature. Possible reasons of the dispersion characteristics of the refractive index below the bandgap have been discussed in detail.
Time-Resolved Infrared Detection of Molecular Nitrogen and Hydrogen Complexes of (η6-C6H6)Cr(CO)2 in Gas Phase
ZHENG Youfeng, WANG Wenhua, LIN Jingu, SHE Yongbo, FIU Kejian
Chin. Phys. Lett. 1992, 9 (6): 329-332 .  
Abstract   PDF(pc) (240KB) ( 376 )
The formations of molecular nitrogen and hydrogen complexcs (η6-C6H6)Cr(CO)2 L(L = N2 and H2) were observed via time-rcsolvcd infrarctd spectroscopy following 3%nm laser photolysis of (η6-C6H6)Cr(CO)3 in the presence of N2 and H2 in gas phase. The rate constants for reactions of (η6-C6H6) Cr(CO)2 with N2 and H2 were measured to be ( 1.4 ±0.1 ) x 105 Torr-1s-1 and ( 2.6 ±0.1) x 105, Torr-1s-1, respectively. The complexes(η6-C6H6)Cr(CO)2 (L = N2 and H2) have lifetimes longer than 1 ms in our experimental conditions implying the N2 and H2 binding energies in (η6-C6H6)Cr(CO)2 L (L = N2 and H2) >17 kcal mol-1.

Temperature of Non-Stationary Kerr-Newman Black Hole
ZHAO Zheng, HUANG Weihua
Chin. Phys. Lett. 1992, 9 (6): 333-336 .  
Abstract   PDF(pc) (130KB) ( 414 )
Following a new method developed by the authors the temperature of a non-stationary Kerr-Newman black hole is given. The temperature is homogeneous everywhere at the event horizon and only depends on the time.
14 articles