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Volume 13 Issue 9
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Original Articles
Transfer Matrix and Yangian Related to Chaplygin-Goryachev Top
XUE Kang, WANG Zhou-fei, GE Mo-lin, ZHANG Hong-biao
Chin. Phys. Lett. 1996, 13 (9): 641-643 .  
Abstract   PDF(pc) (129KB) ( 443 )
A new representation of Yangian for sl(2) is obtained from e(3) algebra. For the given rational solution of the quantum Yang-Baxter equation the algebraic relations of the transfer matrix is discussed and a new transfer matrix related to Chaplygin-Goryachev top are constructed in terms of the generators of Yangian.
Damage Spreading in Neural Network with Local Connection and Cycle Stored Patterns
JI Dao-yun, CHEN Tian-lun
Chin. Phys. Lett. 1996, 13 (9): 644-647 .  
Abstract   PDF(pc) (218KB) ( 369 )
The simulation results of damage spreading show the happening of dynamical chaotic-frozen phase transition in a one-dimensional system, a neural network with cycle stored patterns and local connection. In chaotic phase, the average number of damaged sites and the survival probability surprisingly obey a power-law behavior.
Strange Quark Distribution and Corrections due to Shadowing and Isospin Symmetry Breaking
MA Bo-qiang
Chin. Phys. Lett. 1996, 13 (9): 648-651 .  
Abstract   PDF(pc) (241KB) ( 546 )
The strange sea quarks distributions of nucleons obtained by two global analyses based on available structure function data of muon and neutrino deep inelastic scatterings are different from the strange sea quark distribution measured by the CCFR Collaboration from dimuon events in neutrino scattering. We discuss possible contributions to this discrepancy from the nuclear shadowing in the deuteron and from the isospin symmetry breaking in the sea between the neutron and the proton.
Calculation of fσ on Quark Level
LÜ, Xiao-fu, LIU Yu-xin, ZHAO En-guang
Chin. Phys. Lett. 1996, 13 (9): 652-655 .  
Abstract   PDF(pc) (173KB) ( 426 )
With the recently obtained vacuum configuration of the bilocal field, we have calculated the decay constant fσ of σ-meson in a quantum chromodynamics-based model field theory. From investigating the calculated result, it can be seen that the obtained value of fσ is quite reasonable.

Remarks on the Single-Photon Spectra from CERN-WA80
AI Xiao-bai (Ai Hsiao-bai)
Chin. Phys. Lett. 1996, 13 (9): 656-659 .  
Abstract   PDF(pc) (251KB) ( 453 )
In this letter the author points out that in recent WA80 data an apparent slope parameter of Texp ≈180 MeV/c must not mean the fireball becoming equilibrated in whole at some temperatures throughout the stages of the evolution. The author also demonstrates that Texp is merely a mean value of the temperatures of various high-energy photon sources, and predicts that for higher colliding energies (> 200 A GeV) the shape of the measured single-photon spectra would exhibit some concave curvature, which may be used as a probe for diagnosing quark-gluon plasma.
Calculation of Vibrational Energy Spectra of H2O Molecule by Nonlinear Quantum Theory
CHEN Xiang-rong, GOU Qing-quan, PANG Xiao-feng
Chin. Phys. Lett. 1996, 13 (9): 660-663 .  
Abstract   PDF(pc) (174KB) ( 457 )
The vibrational energy spectra of OH stretch of H2O in both vapour and liquid phases are calculated by using the quantized discrete self-trapping equation of nonlinear quantum theory. The results obtained are in good agreement with the experiment. Meanwhile, it is noted that the behaviour of the distribution of energy levels of high excited states obtained here is useful in optical spectrum research.
Dielectronic Recombination for the Self-Consistent-Field Average Ions
ZHAO Li-bo, LI Shi-chang
Chin. Phys. Lett. 1996, 13 (9): 664-667 .  
Abstract   PDF(pc) (195KB) ( 418 )
A self-consistent-field theoretical method has been developed to treat the dielectronic recombination (DR) of average ions with electrons. Based on the method, the rate coefficients for DR into a special state can be evaluated. As an example, the results for iron have been presented at a defined electron population.
Ultrafast Optical Properties of C70 Thin Film
WANG Cong-fang, A Xi-cheng, XIA Zong-ju, ZOU Ying-hua, QIAN Jiang*, QIAN Shi-xiong*
Chin. Phys. Lett. 1996, 13 (9): 668-671 .  
Abstract   PDF(pc) (232KB) ( 438 )
The relaxation of optically excited carrier in C70 thin film fabricated by physical jet deposition was investigated by femtosecond pump-probe measurements. A transient decrease in transmission was observed indicating induced absorption. In comparison to C60 thin film the initial response of C70 film is laser pulse limited and the long lived component has smaller magnitude. The third order optical nonlinear susceptibility of C70 thin film was determined to be x(3) = 3.3 x 10-11 esu by femtosecond time-resolved optical Kerr effect. From the primarily pulse limited response the dephasing time of C70 thin film has been proved to be shorter than the laser pulse width.

Rayleigh-Enhanced Nondegenerate Four-Wave Mixing
YU Zu-he, MI Xin, JIANG Qian, Ll Xiao-feng, FU Pan-ming
Chin. Phys. Lett. 1996, 13 (9): 672-674 .  
Abstract   PDF(pc) (178KB) ( 481 )
We report a Rayleigh-enhanced nondegenerate four-wave mixing (NFWM) in carbon disulfide. From the Rayleigh-enhanced NFWM spectrum a relaxation time of as short as 220fs was deduced.
A New Method to Suppress the Fanning Noise in the Photorefractive LiNbO3:Fe Crystals
SUN Qian, TIAN Guo-yun, LIU Si-min, XU Jing-jun, ZHANG Guang-yin
Chin. Phys. Lett. 1996, 13 (9): 675-677 .  
Abstract   PDF(pc) (224KB) ( 443 )
A new method to suppress the fanning noise caused by He-Ne laser in the cooperation with Ar+ laser in photorefractive LiNbO3:Fe crystal was successfully realized. This method is simple and efficient. By using this method, fanning-noise-free hologram can be stored in LiNbO3:Fecrystal.
Mutually Pumped Phase-Conjugate Mirror: Sickle Configuration
ZHANG Liang-min, ZHANG Jing-wen, SHAO Zong-shu, MU Xiao-dong, CHEN Huan-chu, JIANG Min-hua
Chin. Phys. Lett. 1996, 13 (9): 678-681 .  
Abstract   PDF(pc) (248KB) ( 450 )
A mutually pumped phase conjugator is demonstrated with a novel photorefractive crystal of copper-doped potassium sodium strontium barium niobate, in which the beams travel in a geometric path similar to the outline of a sickle. The maximum reflectivity is up to 168%. Faster response times are measured and are also simulated as a function of incident beam power ratio. Four available input geometries are found. The phase conjugation signals exist wide range of angular and positional alignment. No apparent cross talk is observed. The faster build-up process of phase conjugation beams is tentatively explained.

Drag Force on a String Fastened to a Sphere Moving in a Viscous Fluid
Shan-tarng Chen
Chin. Phys. Lett. 1996, 13 (9): 682-685 .  
Abstract   PDF(pc) (228KB) ( 531 )
The viscous drag force acting on a thin cotton string fastened to a sphere moving in glycerin has been determined by using a photogate apparatus, showing that the force acting on the string agrees with a simplified 2-dimensional theory for string Reynolds’ number Ns < 0.008.
Local Cooling Effect of Rotation and Formation of Thermal Transport Barrier in Tokamaks
QIU Xiao-ming (X. M. Qiu), DING Ning (N. Ding)
Chin. Phys. Lett. 1996, 13 (9): 686-688 .  
Abstract   PDF(pc) (204KB) ( 390 )
A simple model, rotation-inducing local cooling, for the mechanism on the formation of thermal transport barrier and the increase in rotation velocity is presented. It is shown that the sheared rotation can make electron temperature profile Te(r) steepen near the rotation layer and ▽Te > 0 on some location inside it, in agreement with the experimental observations in tokamaks, such as JT-60U with (poloidal or toroidal) sheared rotation and HL-1M with a biased electrode. Such temperature profile can remarkably improve the energy confinement in tokamaks.
Investigation of Edge Localized Fluctuation in KT-5C Tokamak
ZHAI Kan, WEN Yi-zhi, YU Chang-xuan, LIU Wan-dong, WANG Chao, ZHUANG Ge, XU Zhi-zhan
Chin. Phys. Lett. 1996, 13 (9): 689-692 .  
Abstract   PDF(pc) (220KB) ( 424 )
It is found on KT-5C tokamak that an edge fluctuation mode can be excited by using a pair of floating Langmuir probes. This mode is propagating along the magnetic field with its amplitude decreasing drastically when it is off the magnetic field line. Preliminary feedback experiments show that the broadband edge turbulence can be reduced or enhanced depending upon the phase shift of the feedback network.

Structure Properties of Ternary Hydrides Ni3A1Hx
PAN Yi-wei, ZHANG Wen-qing, CHEN Nan-xian
Chin. Phys. Lett. 1996, 13 (9): 693-695 .  
Abstract   PDF(pc) (162KB) ( 468 )
The structure properties of the ternary hydrides Ni3AIHx are studied by use of the interatomic pair potentials obtained from the first principles electronic structure calculation and Chen-Mobius 3-dimensional lattice inversion method. The heat of formation and volume expansion of the hydrogenized systems are investigated.

Theoretical Study on the Ordered Structure in Lanthanum-Modified Lead Zirconate Titanate
GUI Hong, ZHANG Xiao-wen, GU Bing-lin
Chin. Phys. Lett. 1996, 13 (9): 696-699 .  
Abstract   PDF(pc) (200KB) ( 382 )
The 1/2{111}-type ordered structure observed in lanthanum-modified lead zirconate titanate has been proved to be stable in the next-nearest-neighbor approximation by the eightpoint cluster variation method. The order parameter as a function of the composition of La3+ and lead vacancies and the order-disorder phase diagram have been obtained.

Factors Influencing Thermal Conductivity in Diamond Film
GU Chang-zhi, JIN Zeng-sun, WANG Chun-lei, LÜ, Xian-yi, ZOU Guang-tian, ZHANG Ji-fa*, FANG Rong-chun*
Chin. Phys. Lett. 1996, 13 (9): 700-702 .  
Abstract   PDF(pc) (168KB) ( 594 )
Diamond films were synthesized on Si substrate by electron-assisted chemical vapor deposition method using gas mixtures of methane (or acetone) and hydrogen. Various crystal structures of diamond films were obtained by synthesis with various deposition conditions. The influences of various deposition conditions on thermal conductivity of diamond film were studied. The results show that large-grain (100)-oriented diamond films synthesized at lower concentration of methane and acetone have higher thermal conductivity, and thermal conductivity increases with the increasing in film thickness and the removal of the Sic layer on the back of the film, at last, annealing in ambience of hydrogen is advantageous to acquiring diamond film with high thermal conductivity.

Exact Solution of a Backward Scattering Kondo Model
WANG Yu-peng, PU Fu- ke, (Fu-Cho PU)
Chin. Phys. Lett. 1996, 13 (9): 703-706 .  
Abstract   PDF(pc) (223KB) ( 387 )
To specify the difference between the one-dimensional Kondo problem and the three-dimensional Kondo problem, we consider a model which describes the interaction between one-dimensional free electrons and a magnetic impurity. Bethe ansatz exact results and scaling analysis show that if JF > -| JB |, the Kondo screening occurs. There is no ferromagnetic Kondo screening in such a system but the long range antiferromagnetic Kondo coupling is relevant. As soon as the Coulomb interaction is introduced, the crossovers between the scaling trajectories in the parameter region JF < -| JB | and the trajectories in other parameter regions arise and ferromagnetic Kondo screening may occur.

Photoluminescence Investigation of Charge Build-Up Process in the Emitter of a Double-Barrier Resonant Tunneling Structure
LUO Ke-jian, ZHENG Hou-zhi, ZHANG Ting, LI Cheng-fang, YANG Xiao-ping, ZHANG Peng-hua, ZHANG Wei, TIAN Jin-fa
Chin. Phys. Lett. 1996, 13 (9): 707-710 .  
Abstract   PDF(pc) (238KB) ( 467 )
Charge build-up process in the emitter of a double-barrier resonant tunneling structure is studied by using photoluminescence spectroscopy. Clear evidence is obtained that the charge accumulation in the emitter keeps almost constant with bias voltages in the resonant regime, while it increases remarkably with bias voltages beyond resonant regime. The optical results are in good agreement with the electrical measurement. It is demonstrated that the band gap renormalization plays a certain role in the experiment.
Structure and Properties of Sputtered Pt/Co Multilayers
ZHENG Min, XU Yao, GUO Zhao-hui, WANG Yin-jun
Chin. Phys. Lett. 1996, 13 (9): 711-713 .  
Abstract   PDF(pc) (183KB) ( 446 )
Two series of Pt/Co multilayer films were sputtered under different deposition conditions. The magnetic and magneto-optical properties are found to vary depending on Pt bufferlayer and the number of modulation period. Fine material parameters of Pt/Co multilayers for magneto-optical recording are obtained.
Formation of Carbon Nitride Films by Nitrogen Ion Bombardment on C60 Films
REN Zhong-min, DU Yuan-cheng, YING Zhi-feng, LI Fu-ming, LIN Jing, REN Yun-Zhu, ZONG Xiang-fu
Chin. Phys. Lett. 1996, 13 (9): 714-717 .  
Abstract   PDF(pc) (243KB) ( 626 )
The synthesis of covalent carbon nitride films becomes an important subject in the materials research field. As a new synthetic method two low-energy (400 and 1000eV) nitrogen ion beams are used to bombard on C60 thin films individually. The bombarded films are used for Raman and x-ray photoelectron spectroscopy (XPS) measurements. The results of the analyses show that under the bombardment of 400eV nitrogen ion beam, the film still contains a large amount of undestructed C60 molecules. In the case of l000eV bombardment, only a little amount of C60 molecules is kept undestructed. The experimental results also show that the destructed carbon species will combine chemically with nitrogen ions to form stable covalent carbon nitride, confirmed by the Raman peaks of, e.g., 2240cm-1. The XPS Nls and Cls lines also indicate the formation of covalent carbon nitride in the bombarded films.

Helliwell-Konkowski Conjecture and the Singularities of Cauchy Horizons in 1 + 1-Dimensional Black Holes
WANG Bin, SU Ru-keng
Chin. Phys. Lett. 1996, 13 (9): 718-720 .  
Abstract   PDF(pc) (148KB) ( 364 )
The stability conjecture of Cauchy horizons of black holes suggested by Helliwell and Konkowski is used to investigate the 1+1-dimensional (2D) black holes under perturbations of infalling null dust and of both infalling and outgoing null dust. The result given by this conjecture agrees with that from mass inflation scenario for 2D charged dilaton black hole. For 2D black holes, we show that the Cauchy horizons are unstable and the corresponding singularities exist.
22 articles