Volume 11 Issue 10

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Original Articles
New Exact Solutions of the CDGSK Equation Related to a Non-local Symmetry
LOU Senyue*, RUAN Hangyu, CHEN Weizhong, WANG Zhenli, CHEN Lili
Chin. Phys. Lett. 1994, 11 (10): 593-596 .  
Abstract   PDF(pc) (161KB) ( 1193 )
A non-local symmetry of the Caudrey-Dodd-Gibbon-Sawada-Kotera (CDGSK) equation has been used for finding exact solution in two different ways. Firstly, using the standard prolongation approach, we obtain the finite Lie Bäcklund transformation and the single soliton solution. Secondly, combining some local symmetries and the nonlocal symmetry, we get the group invariant solution which is described by the Weierstrass elliptic function and is deduced to the so-called interacting soliton for a special parameter.
Compensation in Intermittency Strength of the Hard and Soft Components in Hadron-Hadron Collisions
HU Yuan, LIU Lianshou
Chin. Phys. Lett. 1994, 11 (10): 597-600 .  
Abstract   PDF(pc) (245KB) ( 549 )
The controversy in experimental data on the transverse momentum dependence of intermittency at different energies is studied. It is shown that this controversy is due to the appearance of a new component - the jet (or mini-jet) component together with the normal soft one at the collider energies. It is shown that the compensation effect of these two components results in a U shape for the dependence of intermittency indices on the average transverse momentum per event P which is a good quantity to characterize the relative size of soft and hard components in an event. In a linearization approximation the fraction of the soft component can be determined directly from P.

Dependence of Long Range Correlation on Width of Rapidity Gap in High Energy Hadron-Hadron Collisions
YANG Jie*, LIU Lianshou, YANG Zhongle
Chin. Phys. Lett. 1994, 11 (10): 601-604 .  
Abstract   PDF(pc) (184KB) ( 497 )
The dependence of long range correlation in high energy hadron-hadron collisions on the width of rapidity gap is studied, It is shown that the result from a model with only one particle source does not fit the experimental data. In order to get the experimental dependence of long range correlation on the width of rapidity gap at least three particle sources are needed.
Energy Straggling Measurements of l6O and l9F ions in Au and CaF2
WU Zeqing, LU Xiting, JIN Changwen, ZHENG Tao
Chin. Phys. Lett. 1994, 11 (10): 605-608 .  
Abstract   PDF(pc) (135KB) ( 571 )
Energy stragglings of l6O and l9F were measured with heavy-substrate Rutherford backscattering technique. Great deviation was observed between present data and Bohr’s prediction. The accuracy of present experiment is about 10%.
Experimental Results on High Yield C70 Fullerene
LIU Youying, HE Tianxi
Chin. Phys. Lett. 1994, 11 (10): 609-610 .  
Abstract   PDF(pc) (90KB) ( 332 )
The new results of fullerene C70 are given in this paper. The results show a method to produce a large amount of C70 which can be employed for cadidate materials of nonlinear optical devices and used for diamond film growth.
Physical Similarity of Lossy Scatterers
SHI Zhendong, LIU Hongwei
Chin. Phys. Lett. 1994, 11 (10): 611-613 .  
Abstract   PDF(pc) (147KB) ( 909 )
The theory of the physical similarity of lossy electromagnetic systems is used to analyze the lossy scatterers. Emphasis is placed on the analysis of the effects for the deviation of the similarity between the scatterers by virtue of dimensional analysis.
Optical Bistability in Semiconductors with Many-body Coulomb Effects
GONG Shangqing, XU Zhizhan, PAN Shaohua*
Chin. Phys. Lett. 1994, 11 (10): 614-616 .  
Abstract   PDF(pc) (145KB) ( 759 )
The Bloch-like equations for the intracavityinteraction of coherent light with semiconductors below the Mott density are derived. These equations include the many-body Coulomb effects. Steady state analysis reveals the characteristics of bistability and hysteresis in such systems. It is shown that the hysteresis loops increase and that the bistability can be realized more easily due to the many-body effects.
Dissociation of Oxygen on a Polycrystalline Ag Surface: A Second-Harmonic Generation Study
LIU Yanghua, WANG Wencheng, ZHENG Jiabiao*
Chin. Phys. Lett. 1994, 11 (10): 617-619 .  
Abstract   PDF(pc) (176KB) ( 854 )
An optical second-harmonic generation study on the dissociation of oxygen on a polycrystalline Ag surface is reported in this paper. The adsorption of oxygen at room temperature exhibits two kinds of adsorption states: diatomic and atomic states. The existence of atomic state oxygen hinders the further dissociation of diatomic oxygen.
Energy-Level Splitting Measurement by Time-Delayed Laser-Induced Double Gratings
FU Panming, MI Xin, YU Zuhe, LI Xiaofeng, JIANG Qian
Chin. Phys. Lett. 1994, 11 (10): 620-622 .  
Abstract   PDF(pc) (166KB) ( 487 )
We have studied theoretically a time-delayed laser-induced double gratings (TDLIDG) in a Doppler-broadened three-level system. We have shown that the overall accuracy of using TDLIDG for the energy-level splitting measurement is determined by the homogeneous linewidths of the optical transitions.
Formation of Two F+2-Like Centers Coexisting in KCl : Li+, Na+, OH- Crystal
LIN Bizhou, XU Chenghuang, QIU Jizhan, CHEN Guangfu
Chin. Phys. Lett. 1994, 11 (10): 623-625 .  
Abstract   PDF(pc) (128KB) ( 557 )
To enlargen tuning range in a single host material, we have simultaneously created (F+2)Li+,H-(F+2)Na+,H color centers in KCl : Li+, Na+, OH- crystal, whose emission wavelength covers from 1.45 to 2.45μm. The experiments prove that two coexisting F+2-like centers in KCl have high concentration and good stability.
Dependence of Dechanneling on Individual Layer Thicknesses in Strained-Layer Superlattices
PAN Chuankang (C. K. Pan), JIANG Fengyi (F. Y. Jiang)
Chin. Phys. Lett. 1994, 11 (10): 626-629 .  
Abstract   PDF(pc) (176KB) ( 564 )
We show our new channeling measurement results on ZnSe/Zns and GaSb/AlSb superlattices, which are different from the channeling results on strained-layer superlattices in the early publications. A new concept of “effective channel ”, and a calculation formula of “effective channel geometry width” have been presented and derived, the theoretical analysis is in good agreement with the experiment results.
Peierls Instability in Giant Fullerene
WANG Zhijian, YAN Dadong, CAO Zhiliang, LI Wenzhu
Chin. Phys. Lett. 1994, 11 (10): 630-633 .  
Abstract   PDF(pc) (189KB) ( 775 )
The John-Teller effect of the giant fullerene (GF) is studied. We find that in the giant fullerenes, the C-C bonds are dimerized, binding energies are decreased, energy gaps are enlarged, and the symmetries are reduced in the metallic GF but not in the semiconducting GF. The dimerization patterns of these onions are presented. The distortions decrease as the number of carbon atoms on the GFs increases.
Nonlinear Dynamics of Phase Separation in CuCo Alloys
LIU Junming, LIU Zhiguo, WU Zhuangchun
Chin. Phys. Lett. 1994, 11 (10): 634-637 .  
Abstract   PDF(pc) (188KB) ( 775 )
The dynamics of phase separation of CuCo alloys has been studied by numerically solving the nonlinear Cahn-Hilliard equation including thermal noises. The simulations show that phase separation of the alloys within the metastable region is attributed to the composition fluctuations including thermal noises. The present modeling makes it possible to describe the growth and coarsening as concomitant processes.
Level Crossing in a Driven Double Quantum Well
ZHAO Xiangeng
Chin. Phys. Lett. 1994, 11 (10): 638-641 .  
Abstract   PDF(pc) (171KB) ( 892 )
The motion of electrons in a double quantum well under the action of a monochromatic driving laser field is investigated. Closed-form solutions of the quasienergy and Floquet states are obtained with the help of SU(2) symmetry, from which the occurrence of quasienergy crossing is demonstrated to coincide with the coherent destruction of tunneling if the high-frequency laser field is involved.
Electronic Structure in Cd0.96Zn0.04Te Compound: A Synchrotron Radiation Photoemission Study
YANG Fengyuan, FANG Rongchuan, XU Pengshou*, XU Shihong*
Chin. Phys. Lett. 1994, 11 (10): 642-644 .  
Abstract   PDF(pc) (154KB) ( 695 )
We have studied the electronic structure of clean CdZnTe (111) compound using high resolution synchrotron radiation photoemission spectroscopy. Surface states were found in Cd, Te 4d core levels and valence band. The valence band measurement is in good agreement with theoretical calculations using linear muffin-tin orbit method.
Depinning Line of High-Tc Superconductor HgBa2CuO4+x
LI Jie, ZHU Jinsong, SHAO Huiming, DING Shiying, WANG Yening
Chin. Phys. Lett. 1994, 11 (10): 645-648 .  
Abstract   PDF(pc) (205KB) ( 544 )
Mechanical dissipation of high-Tc superconductor compound HgBa2CuO4+x as a function of temperature was measured with the vibrating reed technique. The depinning line determined from the peak temperature of internal friction was found to be higher than that of Bi-based sample but lower than that of Y-based one.
Hawking Effect in 1+1 Dimensional Non-static Space-Time
ZHAO Ren, ZHAO Zheng*
Chin. Phys. Lett. 1994, 11 (10): 649-652 .  
Abstract   PDF(pc) (122KB) ( 533 )
Hawking radiation in 1+1 dimensional non-static space-time described by the coordinates ( t , r ) is researched. Both the tortoise transformation and the method of analytical continuation are developed. The temperature and the location of event horizon of the non-static black hole are shown.
Back Reaction of Evaporating Black Holes Attached to Global Monopoles
YU Hongwei, WANG Yongjiu
Chin. Phys. Lett. 1994, 11 (10): 653-656 .  
Abstract   PDF(pc) (186KB) ( 721 )
The back reaction of evaporating black holes with internal global monopoles is studied by examining the Klein-Gordon equation near the event horizon and computing the renormalized expectation value of the stress-energy tensor for conformally invariant massless scalar fields in two dimensions. The effective radiation temperature up to O(m) is found.
18 articles