Table of contents

20 April 1994, Volume 3 Issue 4 Previous issue    Next issue

GENERAL

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INFINITELY MANY SYMMETRIES OF THE BILINEAR KADOMTSEV-PETVIASHVILI EQUATION LOU SEN-YUE (楼森岳), LIN JI (林机), ZHANG JIE-FANG (张解放), XU XUE-JUN (许学军) Acta Physica Sinica (Overseas Edition), 1994, 3 (4):  241-249.  DOI: 10.1088/1004-423X/3/4/001 Abstract ( 1481 )   PDF (209KB) ( 444 )   A simple formula for symmetries of the bilinear Kadomtsev- Petviashvili equation (BKPE) is given by using a direct method presented by Lou. The symmetry algebra of the BKPE is not isomorphic to those of the usual KP equation though these equations are related by the well known Cole-Hopf transformation.

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NANO-CRYSTALLINE SILICON FILMS PRODUCED BY LAYER-BY-LAYER DEPOSITION TECHNIQUE AND THEIR NOVEL PROPERTIES CHEN MAO-RUI (陈茂瑞), CHEN KUN-JI (陈坤基) Acta Physica Sinica (Overseas Edition), 1994, 3 (4):  250-254.  DOI: 10.1088/1004-423X/3/4/002 Abstract ( 1391 )   PDF (135KB) ( 449 )   We have applied the layer-by-layer deposition technique to the growth of nano-crystalline silicon films by varying the hydrogen plasma exposure time. The tailoring effect of hydrogen plasma has been studied, The novel optical and electronic proper-ties of these films have also been reported.

ATOMIC AND MOLECULAR PHYSICS

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NEW METHOD FOR DETERMINING THREE-PHOTON TRANSITION TENSOR PATTERNS FOR RANDOMLY ORIENTED MOLECULES LIN MEI-RONG (林美荣), LIU YAO-MING (刘耀明), ZHANG BAO-ZHENG (张包铮), PAN XIAO-NING (潘潇宁), CHEN WEN-JU (陈文驹) Acta Physica Sinica (Overseas Edition), 1994, 3 (4):  255-266.  DOI: 10.1088/1004-423X/3/4/003 Abstract ( 1265 )   PDF (278KB) ( 427 )   The method and results are given for the tensor patterns and polarization ratios of three-photon absorption excited by single-laser for randomly oriented molecules. The ratio of oriented average of transition rate for circularly polarized light to that for linearly polarized light, $\Omega$, can be obtained by the simple three-photon transition tensor. For transition of which the tensor has one independent element, we give the value of polarization ratio; for transition of which the tensor contains two independent elements, we also give the possible range of polarization ratio. These results may be helpful for the symmetry assignment of the excited states.

CLASSICAL AREAS OF PHENOMENOLOGY

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NONLINEAR OPTICAL EFFECTS INDUCED BY A z5-TYPE ANHARMONIC POTENTIAL GUO XIAO-JIANG (郭晓江), PAN SHAO-HUA (潘少华) Acta Physica Sinica (Overseas Edition), 1994, 3 (4):  267-278.  DOI: 10.1088/1004-423X/3/4/004 Abstract ( 1219 )   PDF (268KB) ( 438 )   Using the density matrix formalism based on the exact wave functions for a parabolic quantum well with applied electric fields, we derive in this paper analytical expressions for nonlinear optical effects of a z5-type anharmonic potential. A numerical illustration is also given. Moreover, we describe in detail the method for obtaining the anharmonic potential in a doping superlattice.

PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES

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MECHANISM OF HOT ELECTRON GENERATION AND STIMULATED RAMAN SCATTERING IN LASER CAVITY TARGET PLASMA ZHANG JIA-TAI (张家泰), XU LIN-BAO (许林宝), CHANG TIE-QIANG (常铁强), ZHU SEN-CHANG (朱森昌), ZHANG SHU-GUI (张书贵), NIE XIAO-BO (聂小波), WANG WEI-XING (汪卫星), WANG SHI-HONG (王世红), LIU XIU-QIN (刘秀琴), MEI QI-YONG (梅启庸), QI LAN-YING (祁兰英), ZHAO XUE-WEI (赵雪薇), LI SAN-WEI (李三伟), LI WEN-HONG (李文洪), ZHENG ZHI-JIAN (郑志坚), TANG DAO-YUAN (唐道源), XIE PING (谢平), SUN YONG-LIANG (孙永良) Acta Physica Sinica (Overseas Edition), 1994, 3 (4):  279-290.  DOI: 10.1088/1004-423X/3/4/005 Abstract ( 1371 )   PDF (312KB) ( 502 )   Stimulated Raman Scattering (SRS) and X-ray spectrum emitted from many kinds of targets were experimentally investigated on the Nd:glass laser facility Shenguang-I in Shanghai, China. By theoretical analysis and computer simulation for these experiments, the result showed that the mechanism of hot electron generation in laser cavity target was mainly SRS, according to detailed comparison between the cavity target and the plane target. Other results, such as the energy fraction and temperatures of hot electron, energy and angular distribution and wave spectrum in SRS, were also presented in detail.

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

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EFFECT OF THE Ba VACANCY ON THE FLUX PINNING IN YBaxCu3O7-$\delta$ SYSTEM FANG MING-HU (方明虎), CAI MENG (蔡盟), JIAO ZHENG-KUAN (焦正宽), ZHANG QI-RUI (张其瑞) Acta Physica Sinica (Overseas Edition), 1994, 3 (4):  291-296.  DOI: 10.1088/1004-423X/3/4/006 Abstract ( 1193 )   PDF (173KB) ( 432 )   A series of Y123 single phase samples with various Ba vacancy concentration was prepared by making their Ba contents deviate from the stoichiometric composition. The measurements of their structure, superconductivity and flux pinning behaviour were systematically carried out. It is found that, compared with YBa2Cu3O6.96 sample, the strength of the flux pinning in YBaxCu3O7-$\delta$(1.8≤x<2.0) samples is increased, and that there is an optimum value of Ba vacancy concentration for the maximum flux pinning force density. The possible origin of the flux pinning centers to determine the flux pinning behavior at higher field is discussed in detail. We suggest that the flux pinning effect at lower field may stein from the interaction between the vortex and the surfaces of grains, and that the flux pinning mechanism at higher field belongs to the core interaction.

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STRUCTURE AND MAGNETIC PROPERTIES OF LaCo13-BASED ALLOYS YAN XIAO-HUA (鄢晓华), LIANG JING-KUI (梁敬魁) Acta Physica Sinica (Overseas Edition), 1994, 3 (4):  297-302.  DOI: 10.1088/1004-423X/3/4/007 Abstract ( 1336 )   PDF (143KB) ( 383 )   The structure and magnetic properties of two series of LaCois-based alloys, LaCo13-xFex(0≤x≤6) and La1-xRx(Co, Fe)13 (x=0.1,0.2; R=Y, Ge, Pr, Nd Sm, Gd, Tb, Dy, Ho, Er, and Yb), are studied by X-ray diffraction and magnetic mea- surements. In the above-mentioned composotions, all the samples display a structure of NaZn13 type (space group: Fm3c). In LaCo13-xFex system, as the iron content increases, its Curie temperature decreases, while thc magnetic moment per 3d atom increases. This may be explained by a rigid band model. In the other alloy system, the Curie temperature goes through a maxium at R=Gd, and this reflects the influ- ence of R - T interaction. It is also observed that saturation magnetization varies with R and gets lower when R is a heavy rare earth element. The contribution of R is close to that of a free-ion moment. La0.9Pr0.1Co9Fe4 has the largest value 29$\mu$B/f.u.

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X-RAY PHOTOELECTRON EMISSION STRUCTURES OF CuO NANOPARTICLES ZOU BING-SUO (邹炳锁), ZHANG GUI-LAN (张桂兰), TANG GUO-QING (汤国庆), CHEN WEN-JU (陈文驹) Acta Physica Sinica (Overseas Edition), 1994, 3 (4):  303-308.  DOI: 10.1088/1004-423X/3/4/008 Abstract ( 1219 )   PDF (198KB) ( 425 )   In this paper we report the X-ray photoemission characteristics of CuO nanoparticles with surface modifications. We found the enhancement of interatomic resonant charge transfer and multi-electron relaxation processes in the coated CuO nanoparticles, which were in agree-ment with the conclusions of polaron-related structural transition appearing under quantum confinement and dielectric confinement effects, as observed in the optical absorption and infrared vibration spectra of this system.