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Volume 8 Issue 10
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Original Articles
Quantum Group Constructure of Non-standard R-matrix for Yang-Baxter Equation
GE Molin, SUN changpu*, XUE Kang*
Chin. Phys. Lett. 1991, 8 (10): 495-498 .  
Abstract   PDF(pc) (158KB) ( 387 )
By taking the concept of weight conservation into account, new solutions of Yang-Baxter equation without spectral parameter are obtained through the non-standard R-matrix on the tensorial space V1/2 Vj (j ≠1/2) in terms of the irreducible representation of the quantum universal enveloping algebra SLq (2). The non-standard R-matrix R1/21 is obtained in an explicit form for j= 1.

Aharonov-Anandan Phase in the Degenerate Parametric Amplifier
QIAN Tiezheng, XU Jingbo, GAO Xiaochun
Chin. Phys. Lett. 1991, 8 (10): 499-502 .  
Abstract   PDF(pc) (160KB) ( 559 )
As a non-adiabatic generalization of a recent work of Gerry, the manifestation of the Aharonov-Anandan phase in the degenerate parametric amplifier of quantum optics is discussed by making use of the Lewis-Riesenfeld quantum theory. We find the Lewis invariant for the system and study its evolution. The Aharonov-Anandan phase is then calculated and the connection between the Aharonov-Anandan phase difference and the average photon-number of the output field is obtained. Finally, the observable effect of the phase difference is investigated.
Discussion on the Geometric Structure of Strange Attractor
LIU Zengrong, CAO Yongluo
Chin. Phys. Lett. 1991, 8 (10): 503-506 .  
Abstract   PDF(pc) (233KB) ( 504 )
We discuss the transversal heteroclinic cycle formed by hyperbolic periodic points of diffeomorphism on the differential manifold. We point out that every possible kind of transversal heteroclinic cycle has the Smalehorse property and the unstable manifolds of hyperbolic periodic points have the closure relation mutually. Therefore the strange attractor may be the closure of unstable manifolds of a countable number of hyperbolic periodic points. The Hénon mapping is used as an example to show that the conclusion is reasonable.
Influence of Hydrodynamic Motion on the Mass Effect in the < PT > Distribution of High Energy Nuclear Collisions
Chin. Phys. Lett. 1991, 8 (10): 507-510 .  
Abstract   PDF(pc) (186KB) ( 355 )
Contrary to that without considering the hydrodynamic motion, the mass effect in the transverse momentum distribution of high energy nuclear collisions is found not negligible at high temperature after the hydrodynamic motion is considered. So on the occasions for high temperature, such as the formation of quark-gluon-plasma, mass effect must be taken into account.

Small Signal Gain in Tapered Free-Electron Lasers of Oscillator Configuration
SHI Yijin, LAN Ke
Chin. Phys. Lett. 1991, 8 (10): 511-514 .  
Abstract   PDF(pc) (190KB) ( 531 )
A quadrature for small signal gain (SSG) in tapered free electron laser (FEL) is given. In contrast to the uniform case, the optimum of gain is not at v = 1.303 of energy mismatch, and it depend on the taper. Using the antenna array concept, the spontaneous emission is derived and it shows that Madey's theorem is still valid. The generalization horn one to three dimensions is given and degradation of SSG due to the collimation excursion of the axes of the optical, electron beam and undulator can be included as well. The comparision with Boeing's FEL experiment is carried out also.

Photorefractive Properties of Paraelectric Copper Doped Potassium Tantalate Niobate
GUAN Qingcai, WANG Jiyang, WANG Min, LIU Yaogang, WEI Jingqian, ZHANG Zhiguo*, YANG Changxi*, YE Peixian*
Chin. Phys. Lett. 1991, 8 (10): 515-517 .  
Abstract   PDF(pc) (124KB) ( 425 )
The photorefractive properties of Cu doped KTa1-x NbxO3 have been studied by using two-wave mixing method. The diffraction efficiency reaches as high as 52% under an electric field. The dependences of diffraction efficiency on interference angles and applied fields have been studied. The maximum light induced index change is found to be 2.33 x10-5 and the photorefraction sensitivity calculated is 5 x 10-6cm2/J. Experimental results demonstrate that electrons are the dominant charge carriers.

Influence of Modified Collisional Damping on Saturation of Plasma Beat Waves
ZHONG Quande
Chin. Phys. Lett. 1991, 8 (10): 518-520 .  
Abstract   PDF(pc) (135KB) ( 481 )
The influence of the collisional damping modified by the electron quiver velocity in the driving laser fields on the asymptotic behavior of the plasma beat waves is studied numerically. Compared with un-modified case, it is shown that the critical detuning and critical driving laser amplitudes are diminished, and the minimal driving laser amplitudes, which make the saturation amplitude of the excited plasma wave reach the maximum, are lessened also.
Structure Refinement of Bi2Sr1.855Ca1.145Cu2O8 from Neutron Data
YE Chuntang, YANG Jilian, ZHANG Baisheng, LI Jizhou, KANG Jian, JIN Lan, DING Yongfan, HE Yusheng, ZHANG Jincang, HE Aisheng, XIANG Jiong
Chin. Phys. Lett. 1991, 8 (10): 521-524 .  
Abstract   PDF(pc) (152KB) ( 382 )
Neutron diffraction study on the structure of Bi2Sr1.855Ca1.145Cu2O8 was carried out. Data refinements show that the average subcell structure for Bi2Sr1.855Ca1.145Cu2O8 in the best fit of the space group Fmmm and the structure is described by alternate stacking of SrO-CuO2-Ca-CuO2-SrO slab and a double BiO layers. An oxygen layer sandwiched by the bismuth layers was confirmed.
Formation of Nitride Cu3N by MeV N-Ion Implantation into Cu
CUI Fuzhai*, A.M. Vredenberg, R. de Reus, F. W. Saris
Chin. Phys. Lett. 1991, 8 (10): 525-528 .  
Abstract   PDF(pc) (211KB) ( 537 )
Experimental evidences are presented to show the formation of nitride, Cu3N, in pure Cu sample by N-ion implantation. This result is obtained in the case of MeV ion implantation. Previous experiments showed that this compound can not be formed by N-ion implantation into Cu at incident energy of about 100 keV. This finding indicates there exist certain differences in phase formation by ion implantation at the two energies.
Microstructural Characterization of Epitaxial GaAs on Separation-by-Implanted- Oxygen Substrates
ZHU Wenhua, LIN Chenglu, NI Rushan, LI Aizhen, ZOU Shichang, P. L. F. Hernment*
Chin. Phys. Lett. 1991, 8 (10): 529-532 .  
Abstract   PDF(pc) (242KB) ( 489 )
The direct growth of GaAs by molecular-beam epitaxy on separation-by-implanted-oxygen substrates is demonstrated. Cross-sectional transmission electron microscopy, Rutherford backscattering and channeling techniques have been employed to characterize these layers. Microtwins and threading dislocation are the predominant defects in the layers. Most of the misfit dislocation are confined within the GaAs and Si interface region by forming a type of edge dislocation.
Spectral Properties of the One-Dimensional SILK Quasilattices
LIU Youyan, LUAN Changfu, DENG Wenji, HAN Hui, ZOU Nanzhi*
Chin. Phys. Lett. 1991, 8 (10): 533-536 .  
Abstract   PDF(pc) (188KB) ( 441 )
An one-dimensional three-tile quasilattice model is introduced. A multifractal spectral behavior has been found analytically and confirmed by the numerical simulation. The renormalization-group method has been used to study the asymptotical behavior of the spectrum, a pseudo-seven-cycle of trace map is found.
Linear Modes Around a Polaron in Quasi-One-Dimensional Bridged Mixed-Valence Platinum Compounds
PENG Jingcui
Chin. Phys. Lett. 1991, 8 (10): 537-540 .  
Abstract   PDF(pc) (178KB) ( 435 )
Linear modes around a polaron in the quasi-one-dimensional halogen-bridged mixed-valence platinum compounds is studied using quasi-harmonic approx-imation. The additional modes, i. e., so-called localized mode and localized bending mode are calculated numerically.
Hall Effect of an Oriented Superconducting YBa2Cu3Oy Film
HE Zhenhui, SHA Jian, WANG Shunxi, CHENG xiangai, ZHOU Guien, ZHANG Qirui, SHI Wangzhou, YAO Weiguo, QI Zhenzhong
Chin. Phys. Lett. 1991, 8 (10): 541-543 .  
Abstract   PDF(pc) (136KB) ( 445 )
A superconducting YBa2Cu3Oy thin film, which is well oriented at (001) direction and in which no grain boundary is observed in the resolution limit of scanning electron microscope micrograph, is selected for the Hall effect measurement from 80 to 220K under a magnetic field of 3T. A very narrow and negative peak of the Hall voltage (VH) is found in the superconducting transition region. A linear dependence of the carrier concentration (nH) on temperature is found in the normal state. The appearance of such a negative peak is attributed to the intrinsic anisotropy of the Hall coefficient (RH) related to the direction of the applied field and current.
Twin Domain Fragmentation in YBa2Cu3 O7-δ Under Electron Irradiation
SHI Tiansheng, WANG Geya, ZHU Jie, CHEN Yixing, ZHANG Jihua
Chin. Phys. Lett. 1991, 8 (10): 544-547 .  
Abstract   PDF(pc) (169KB) ( 408 )
Detwinning and retwinning processes in the orthorhombic YBa2Cu3 O7-δ have been directly observed under appropriate electron irradiation by transmission electron microscope. These processes can be repeated many times and are accompanied by twin domain fragmentation and appreciable increase of twin interface density, which is a potential pinning center in YBa2Cu3 O7-δ.The meaning of this effect in raising Jc of the material YBa2Cu3 O7-δ is suggested and discussed.
Hawking Radiation from a Non-static Black Hole
ZHAO Zheng, DAI Xianxin
Chin. Phys. Lett. 1991, 8 (10): 548-550 .  
Abstract   PDF(pc) (92KB) ( 568 )
A method exactly determining an event horizon and its temperature in a non-static space-time is proposed. Using the generalized Tortoise coordinate, we give exact location of event horizon and exact Hawking temperature for a general spherically symmetric evaporating black hole.
15 articles