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Volume 7 Issue 9
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Original Articles
A SIMPLE DERIVATION OF FIELD THEORY OF ISING QUANTUM CHAIN
XU Bowei
Chin. Phys. Lett. 1990, 7 (9): 385-387 .  
Abstract   PDF(pc) (32KB) ( 364 )
A simple derivation of the field theory of Ising quantum chain shows that the Ising model is equivalent to the free Majorana real spinor field. At the critical point, the field equation is conformally covariant.
MEASUREMENT OF THE NUCLEAR SPIN RELAXATION OF 131Xe IN 87Rb ATOMS
LIU Zidong, SUN Xianping, ZENG Xizhi, HE Qiang
Chin. Phys. Lett. 1990, 7 (9): 388-390 .  
Abstract   PDF(pc) (43KB) ( 506 )
131Xe nuclear spin relaxation rate as a function of cell temperature and buffer gas pressure has been measured by Faraday rotation method. Experimental results show that spin exchange rate of 131Xe with 87Rb is C = 1.68 x 10-21 m3s-1, Breit-Rabi parameter is X=4.4, and rate constant for three body formation of Van der Waals molecules is Z=5.1x 10-44m6 s-1.
OPTICAL FIELD INDUCED CIRCULAR BIREFRINGENCE DUE TO COLLISION-INDUCED ZEEMAN COHERENCE IN Sm VAPOR
GONG Qihuang, ZOU Yinghua, LIN Zhouting*
Chin. Phys. Lett. 1990, 7 (9): 391-393 .  
Abstract   PDF(pc) (40KB) ( 380 )
An optical field induced circular birefringence due to collision-induced Zee-man coherence in Sm with He has been observed. The integrated intensity and linewidth of the signal have been measured as a linear function of buffer gas pressure. The cross section for destruction of orientation in the ground state of Sm with He has been obtained.
TUNABLE HIGH-POWER BaB2O4 OPTICAL PARAMETRIC OSCILLATOR PUMPED AT 355nm
XU Zuyan, DENG Daoqun, WANG Yunping, ZHENG Wanhua, LIU Xiang, WU Baichang*, CHEN Chuangtian*
Chin. Phys. Lett. 1990, 7 (9): 394-397 .  
Abstract   PDF(pc) (52KB) ( 633 )
We report the operation of a β- BaB2O4 (BBO) optical parametric oscillator (OPO) broadly tunable in the visible and the near infrared. Quantum efficiency of 22.7% for the signal and 34.1% for the idler corresponding to the total energy conversion efficiency of 25.9% has been achieved. The maximum average output power and the maximum output energy reached 220m W and 22rnJ/pulse, respectively. By changing the matching angle of the OPO, the output wavelength was continuously scanned throughout 425-2144nm.
CYLINDRICAL ENVELOPE SOLITARY WAVES
HUANG Guoxiang, LOU senyue, DAI xianxi
Chin. Phys. Lett. 1990, 7 (9): 398-401 .  
Abstract   PDF(pc) (43KB) ( 288 )
The method of multiple-scales is used to investigate the nonlinear modulation of capillary-gravity waves with cylindrical symmetry. We find that the evolution of wave-packets is described by a nonlinear schrödinger-like equation i(U + U/2r) + αUξξ + β|U|2U = 0. Some exact and explicit cylindrical envelope solitary wave solutions are also obtained by means of variable transformations.
EXACT SOLUTIONS OF SEMI-INFINITE CRACK IN A STRIP
FAN Tianyou
Chin. Phys. Lett. 1990, 7 (9): 402-405 .  
Abstract   PDF(pc) (41KB) ( 589 )
This study presents a procedure for solving semi-infinite crack which is a very useful model in geophysics, seismology and engineering. With the help of conformal transformation mapping. the region in a physical plane onto the interior of a unit circle in a plane, any case of this kind of problems can be solved unifiedly, and some exact solutions are obtained.
WU’S SOLITON IN A SLOPING TROUGH
YAN Jiaren, YOU Jianqiang
Chin. Phys. Lett. 1990, 7 (9): 406-409 .  
Abstract   PDF(pc) (38KB) ( 348 )
The expression of Wu’s hydrodynamic soliton in a sloping trough was derived wing the perturbation method of multiple scales. It showed that the soliton slowly moves toward the shallow end with uniform acceleration, which is consistent with Wu’s experiment.
SUPPRESSING EFFECT OF ELECTROSTATIC WAVES ON DRIFT WAVE INSTABILITY
YIN Yongxiang
Chin. Phys. Lett. 1990, 7 (9): 410-413 .  
Abstract   PDF(pc) (46KB) ( 386 )
The trajectory of charge particles will be changed by electrostatic wave with a large amplitude in plasma. The dispersion relation of drift waves is derived with the help of integration along the changed trajectory. It shows that the drift wave instability can be suppressed by so-called “quasi-Larmor radius effect” as long as the condition, K . Se > K . Si, is satisfied, where K is the wave number of drift wave, Se and Si are the amplitudes of shift of electrons and ions, respectively.
STUDIES ON PHOTOREFRACTIVE CRYSTAL LEAD BARIUM NIOBATE
SONG Yongyuan, JIANG Quanzhong, SUN Daliang, CHEN Huanchu, ZHANG Peilin*, ZHONG Weilie*
Chin. Phys. Lett. 1990, 7 (9): 414-417 .  
Abstract   PDF(pc) (64KB) ( 415 )
The optical quality Pb1-xBaxNb2O6 single crystals have been grown by Czochraski method from the melt. Their structure, dielectric, ferroelectric properties were studied. Transmission spectra, two-wave maxing properties were measured. This crystal will be an available material for photorefractive applications.
STUDY OF NEUTRON IRRADIATED a-Si:H
WANG Shulin, CHENG Ruguang, QI Mingwei, TANG Wenguo, SHEN Xuechu, GAO Jijin
Chin. Phys. Lett. 1990, 7 (9): 418-420 .  
Abstract   PDF(pc) (0KB) ( 152 )
Neutron transmutation doping (NTD) effect in hydrogenated amorphous silicon (a-Si:H) has been reexamined. There is no increase of both dark and photoconductivity of neutron irradiated a-Si:H after annealing at 180°C or 240°C . Our experimental results support Burnett et al. who contradict the finding that NTD in a-Si:H is effective by Hamanaka et al.
IDENTIFICATIONS OF PHOTOLUMINESCENCE AND DEEP LEVEL TRANSIENT SPECTRA FOR Te-DOPED A1xGa1-xAs
KANG Junyong, HUANG Qisheng, LIN Hong, CHEN Chao
Chin. Phys. Lett. 1990, 7 (9): 421-424 .  
Abstract   PDF(pc) (53KB) ( 432 )
A bound-exciton and a donor-acceptor(D-A) pair emission in photoluminescence are identified for Te-doped A1xGa1-xAs. The D-A pair emission near band edge is assigned as Te-related donor to carbon acceptor transition and the donor binding energy is determined as a function of composition x up to 0.75. Except the deep DX level, a new shallower deep state is found in deep level transient spectra under light illumination and is associated with Te-related donor state in PL.
FORMATION OF THERMAL MAGNETOKINKS OF FLUX LINES AND ITS EFFECT ON MAGNETORESISTANCE IN HIGH Tc SUPERCONDUCTORS
LI Xiaoguang, MAO Xianglei, CHEN Lin, WANG Yu, ZHANG yuheng*
Chin. Phys. Lett. 1990, 7 (9): 425-428 .  
Abstract   PDF(pc) (38KB) ( 406 )
We proposed that the thermal magnetokinks in flux lines can form due to thermal activation in high Tc superconductors. This implies that a flux line is no longer a straight one. Basing on this model, we discussed preliminarily the behaviour of magnetoresistance.

CRYSTALLIZATION OF AMORPHOUS Fe62CO15.5Nd4B18.5 ALLOY AND ITS INFLUENCE ON HARD MAGNETIC PROPERTIES
SHEN Baogen, YANG Linyuan, ZHANG Junxian, WO Feng, NING Taishan, ZHAO Jiangao, GUO Huiqun, ZHAN Wenshan
Chin. Phys. Lett. 1990, 7 (9): 429-432 .  
Abstract   PDF(pc) (51KB) ( 600 )
Magnetic properties and crystallization of amorphous Fe62CO15.5Nd4B18.5 alloy are studied. The Curie temperature of the present sample is l27K higher than that of amorphous Fe77.5Nd4B18.5 alloy, but their crystallization temperature is compatible with each other. A coercive field of 2.34kOe, a remanence of 12.3kG and an energy product of 11.6MGOe are obtained at room temperature in the Fe62CO15.5Nd4B18.5 alloy annealed at 650°C. The 15.5at.%-Co substitution for Fe results in an increase of about 1l0K in Tc of 2:14:1 phase.
13 articles