Current Issue

Volume 10 Issue 6
Online Date:
Previous Issue    Next Issue
Original Articles
Controlling Chaos Using Modified Lyapunov Exponents
TAN Yi, HE Xiantu (X. T. He), CHEN Shigang (S. G. Chen)
Chin. Phys. Lett. 1993, 10 (6): 321-324 .  
Abstract   PDF(pc) (235KB) ( 485 )
We suggested a method using a small perturbation to modify Lyapunov exponents of the unstable periodic orbit for controlling chaos. The benefit of this control scheme is studied and the effect of noise is discussed. Based on these studies, a more practical control method is recommended, and some experiments can be better understanded.
Initial-State Radiation in Inclusive Photon Spectroscopy from Electron-Positron Annihilation
GU Yifan
Chin. Phys. Lett. 1993, 10 (6): 325-328 .  
Abstract   PDF(pc) (242KB) ( 438 )
We demonstrate that the effect of the initial-state radiation can be observed in the inclusive photon spectrum from electron-positron annihilation by careful analysis of the data collected in a detector optimized for high resolution measurement of photons. We present the first example of a photon line from radiative corrections of the J/ψ, resonance at total center-of-mass energy far above its mass. We also discuss potential applications of such effect in future electron-positron experiments.
Supersymmetric QCD Correction to t → H+b
HU Bingquan, LI Chongsheng, YANG Jinmin
Chin. Phys. Lett. 1993, 10 (6): 329-332 .  
Abstract   PDF(pc) (178KB) ( 336 )
We computed the O(αs) virtual gluino correction to t → H+b 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 up to 8% reduction in the partial width relative to the tree-level result. Finally, we compared the correction with quantum colourdynamics and electroweak corrections.

Evolution of Vector Boson Distribution
XU Zaixin, ZHU Wei
Chin. Phys. Lett. 1993, 10 (6): 333-335 .  
Abstract   PDF(pc) (109KB) ( 425 )
The strong interaction effect on the vector boson distribution is discussed. The three-term expressions of the vector boson distribution inside quark and gluon in leading approximation are given. Our result shows that the strong interaction will effect not only the x-, but also the Q2-dependence for the distributions.
Quasi-dumbbell Structure of C70 Molecule
ZHAN Keming, LI Panlin
Chin. Phys. Lett. 1993, 10 (6): 336-339 .  
Abstract   PDF(pc) (261KB) ( 568 )
C70 should be a quasi-dumbbell molecule formed by dimerization of two 3/5 C60 spheres. This paper calculated the concave dihedral angle Lσ at the waist of C70 molecule, the distance of two spherical centres of the dumbbell and some other geometric parameters of C70 molecule model.

Observation of Self-pumped Phase Conjugation for Two Mutually Coherent Input Beams in a KNSBN Crystal
WU Xiaoguang*, HU Xierong*, SHAO Zhongsu, CHEN Huanchu, SONG Yongyuan
Chin. Phys. Lett. 1993, 10 (6): 340-342 .  
Abstract   PDF(pc) (171KB) ( 417 )
Two coherent or incoherent stable self-pumped phase conjugations have been obtained simultaneously in a Ce-doped (K0.5Na0.5)2y (Sr0.61 Ba0.39)1-y Nb2O6(KNSBN) crystal by using two mutually coherent input beams from a He-Ne laser, and energy translation from one beam to another induces self-pumped phase conjugative reflectivity of one beam above 100%.

Nonlinear Standing Waves in a Tube
MAA Dah-You
Chin. Phys. Lett. 1993, 10 (6): 343-346 .  
Abstract   PDF(pc) (189KB) ( 520 )
Theory of lossless nonlinear standing waves in tubes is extended to the case when dissipation exists due to the boundary layer inside the tube. And the viscous loss is taken care of with a complex wave number. The solutions thus obtained for the nonlinear standing wave satisfy exactly the hydrodynamic equations. The unusual situations encountered in developing the formulae of the field parameters into their frequency components are discussed and solutions proposed.

Dimensional Analysis and Physical Similarity of Lossy Electromagnetic Systems
SHI Zhendong, DING Chunsheng, CHEN Jiayu
Chin. Phys. Lett. 1993, 10 (6): 347-350 .  
Abstract   PDF(pc) (212KB) ( 682 )
The dimensional analysis is applied to the model measurements of lossy electromagnetic systems. The physical similarity between prototype and model system is given. By this theory, it is predictable that which conditions for the model system should be satisfied in order to get a result similar to the prototype of lossy electromagnetic phenomenon.
Unified Theory of Edge Turbulence in High- and Low- Density Tokamaks
HU Shuanghui, HUANG Lin, QIU Xiaoming (X. M. Qiu)
Chin. Phys. Lett. 1993, 10 (6): 351-354 .  
Abstract   PDF(pc) (212KB) ( 477 )
A new theoretical model, which includes density and temperature gradients and impurity radiation effects, for the edge turbulence in high- and low-density tokamaks is established on the magnetohydrodynamics. The different drive effects in the turbulent evolution are discussed and the mechanism of nonlinear saturation is investigated. The fluctuation levels and the associated diffusion coefficients at the turbulent saturation state are analytically given. The theoretical results are in agreement with the experimental observations on both high- and low-density tokamaks.
Experimental Studies of Reversed Field Pinch in SWIP-RFP Device
ZHANG Peng, FANG Shuiquan, LI Jieping, LUO Cuiwen, LI Qiang, BI Dingguo, YI Ping, XU Ying
Chin. Phys. Lett. 1993, 10 (6): 355-358 .  
Abstract   PDF(pc) (172KB) ( 419 )
The setting up reversed field pinch (RFP) discharges have been realized in three cases of time matched operation with self-reversal effect and toroidal field control. The setting up RFP conditions and configurations have been studied in different conditions.
Diamond Polycrystal Powder Formation Directly from Gas Phase in a Plasma Jet System
JIANG Xiangliu, QIN Sizhan, ZHANG Xiufang, XUE Zengquan, PANG Shijin
Chin. Phys. Lett. 1993, 10 (6): 359-361 .  
Abstract   PDF(pc) (267KB) ( 420 )
Diamond polycrystal powder has been produced directly from gas phase in an arc discharge plasma jet system. Acetylene diluted in argon was used as hydrocarbon source gas. The product was the mixture of diamond polycrystal powders and soot. The 3C cubic phase diamond which is dominant, and the mixture phases of cubic and 6H hexagonal diamond are identified in the produced diamond polycrystal powders by electron diffraction patterns.
Growth Zone Boundary in a Self-Frequency Doubling Crystal of Nd3+-Doped YA13(BO3)4
ZHAO Qinglan, HUANG Yisen
Chin. Phys. Lett. 1993, 10 (6): 362-364 .  
Abstract   PDF(pc) (267KB) ( 452 )
One of the main defects in the self-frequency doubling crystal of Nd3+-doped YA13(BO3)4 (NYAB), which may be the key factor to influence the crystal performance, is the growth zone boundary that has been identified by means of x-ray diffraction topography. The characteristic boundary is formed usually by the basal plane and the pyramidal planes or by the pyramidal planes themselves.
Local Structure and Bond Orientation Order of Liquid Metal Pb
CHEN Kuiying, LI Qingchun
Chin. Phys. Lett. 1993, 10 (6): 365-368 .  
Abstract   PDF(pc) (174KB) ( 505 )
Molecular dynamics simulations of computer have been performed on the local structure and bond orientation order of liquid metal Pb at 623 K, Results show that, at point near melting temperature, the local structures of liquid metal Pb show cubic symmetry, and the long-range correlation of this symmetry is weak.
Acoustoelectric Nonlinear Effect of Vertically Incident Bulk Wave at LiNbO3/Si Boundary
LI Wei, YIN Jianhua, SHUI Yongan
Chin. Phys. Lett. 1993, 10 (6): 369-370 .  
Abstract   PDF(pc) (124KB) ( 323 )
The acoustoelectric nonlinear effect due to the electrical nonlinearity of semi-conductor has been observed as presented in this article by using vertically incident bulk wave at LiNbO3/Si boundary. This effect is closely related to the bias voltage applied to the semiconductor Si. The results we have obtained provide a feasible new structure for the further study of acoustoelectric nonlinear coupling between piezoelectrics and semiconductors.
Effect of the Two Distinct Bi on the Electronic Structure of BaBiO3
ZHANG Zhipeng, SHEN Yaowen, HUANG Meichun
Chin. Phys. Lett. 1993, 10 (6): 371-373 .  
Abstract   PDF(pc) (176KB) ( 727 )
The band-structure of BaBiO3 has been calculated by using LMTO-ASA method to a supercell, in which the breathing-mode displacements of oxygen atoms and two oxidation states of Bi were considered. The results indicate that BaBiO3 is a semiconductor with a gap of 1.5eV, which, unlike previous calculations, is essentially consistent with experiments.

Ellipsometric Spectra and Refractive Index of Polyaniline
MO Dang, LIN Yongyao, GONG Kecheng, ZHANG Guiping, YUAN Renkuan
Chin. Phys. Lett. 1993, 10 (6): 374-376 .  
Abstract   PDF(pc) (159KB) ( 1154 )
Ellipsometric spectra of polyaniline which is one kind of new conducting polymers are measured. The complex dielectric function, the index of refraction and the absorption coefficient of insulating polyaniline as the functions of photon energy are obtained. The absorption spectra obtained by us and other authors are compared and analyzed.
63Cu NMR Study of Cu83-Zn17 Mixed Powders During Mechanical Alloying
LI Baiqin, WANG Yening
Chin. Phys. Lett. 1993, 10 (6): 377-380 .  
Abstract   PDF(pc) (248KB) ( 505 )
The variations of the 63Cu NMR, spectra of Cu83-Zn17 powder mixtures with time of ball milling arc shown and analyzed. With increasing the ball-milling time, the α phase is developed as terminal phase over 5h. accompanying the emergence aid following disappearance of siiiall aniount β phase. The microstructural changes after aging at room temperature are also detected. Some valuable conclusions related to the alloying reaction on an atomic scale have been drawn.
The Specific Heat Caused by Solitons in the Protein Molecules
PANG Xiaofeng
Chin. Phys. Lett. 1993, 10 (6): 381-384 .  
Abstract   PDF(pc) (210KB) ( 652 )
The property of specific heat caused by the solitons excited in the protein molecules has been discussed in terms of the equations of motion of operators for the excitons and the phonons in our theory. The values of specific heat arisen from the solitons are consistent completely with the experimental data. The results obtained show ful1y that the soliton is existent indeed and biologically relevant in the protein molecules.

18 articles