当期目录

1994年, 第3卷, 第4期　刊出日期：1994-04-20 上一期    下一期

GENERAL

Select

INFINITELY MANY SYMMETRIES OF THE BILINEAR KADOMTSEV-PETVIASHVILI EQUATION 楼森岳, 林机, 张解放, 许学军 1994 (4):  241-249.  doi: 10.1088/1004-423X/3/4/001 摘要 ( 0 )   PDF(209KB) ([an error occurred while processing this directive])   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. 相关文章 | 计量指标

Select

NANO-CRYSTALLINE SILICON FILMS PRODUCED BY LAYER-BY-LAYER DEPOSITION TECHNIQUE AND THEIR NOVEL PROPERTIES 陈茂瑞, 陈坤基 1994 (4):  250-254.  doi: 10.1088/1004-423X/3/4/002 摘要 ( 0 )   PDF(135KB) ([an error occurred while processing this directive])   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. 相关文章 | 计量指标

ATOMIC AND MOLECULAR PHYSICS

Select

NEW METHOD FOR DETERMINING THREE-PHOTON TRANSITION TENSOR PATTERNS FOR RANDOMLY ORIENTED MOLECULES 林美荣, 刘耀明, 张包铮, 潘潇宁, 陈文驹 1994 (4):  255-266.  doi: 10.1088/1004-423X/3/4/003 摘要 ( 0 )   PDF(278KB) ([an error occurred while processing this directive])   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,Ω, 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. 相关文章 | 计量指标

CLASSICAL AREAS OF PHENOMENOLOGY

Select

NONLINEAR OPTICAL EFFECTS INDUCED BY A z5-TYPE ANHARMONIC POTENTIAL 郭晓江, 潘少华 1994 (4):  267-278.  doi: 10.1088/1004-423X/3/4/004 摘要 ( 0 )   PDF(268KB) ([an error occurred while processing this directive])   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. 相关文章 | 计量指标

PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES

Select

MECHANISM OF HOT ELECTRON GENERATION AND STIMULATED RAMAN SCATTERING IN LASER CAVITY TARGET PLASMA 张家泰, 许林宝, 常铁强, 朱森昌, 张书贵, 聂小波, 汪卫星, 王世红, 刘秀琴, 梅启庸, 祁兰英, 赵雪薇, 李三伟, 李文洪, 郑志坚, 唐道源, 谢平, 孙永良 1994 (4):  279-290.  doi: 10.1088/1004-423X/3/4/005 摘要 ( 0 )   PDF(312KB) ([an error occurred while processing this directive])   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. 相关文章 | 计量指标

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

Select

EFFECT OF THE Ba VACANCY ON THE FLUX PINNING IN YBaxCu3O7-δ SYSTEM 方明虎, 蔡盟, 焦正宽, 张其瑞 1994 (4):  291-296.  doi: 10.1088/1004-423X/3/4/006 摘要 ( 0 )   PDF(173KB) ([an error occurred while processing this directive])   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-δ(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. 相关文章 | 计量指标

Select

STRUCTURE AND MAGNETIC PROPERTIES OF LaCo13-BASED ALLOYS 鄢晓华, 梁敬魁 1994 (4):  297-302.  doi: 10.1088/1004-423X/3/4/007 摘要 ( 0 )   PDF(143KB) ([an error occurred while processing this directive])   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 29μB/f.u. 相关文章 | 计量指标

Select

X-RAY PHOTOELECTRON EMISSION STRUCTURES OF CuO NANOPARTICLES 邹炳锁, 张桂兰, 汤国庆, 陈文驹 1994 (4):  303-308.  doi: 10.1088/1004-423X/3/4/008 摘要 ( 0 )   PDF(198KB) ([an error occurred while processing this directive])   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. 相关文章 | 计量指标