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.

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.

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.

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 z^{5}-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

ZHANG JIA-TAI, XU LIN-BAO, CHANG TIE-QIANG, ZHU SEN-CHANG, ZHANG SHU-GUI, NIE XIAO-BO, WANG WEI-XING, WANG SHI-HONG, LIU XIU-QIN, MEI QI-YONG, QI LAN-YING, ZHAO XUE-WEI, LI SAN-WEI, LI WEN-HONG, ZHENG

Chin. Phys. B 1994, 3 (4): 0279; doi: 10.1088/1004-423X/3/4/005
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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

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 YBa_{2}Cu_{3}O_{6.96} sample, the strength of the flux pinning in YBa_{x}Cu_{3}O_{7-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.

The structure and magnetic properties of two series of LaCois-based alloys, LaCo_{13-x}Fe_{x}(0≤x≤6) and La_{1-x}R_{x}(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 NaZn_{13} type (space group: Fm3c). In LaCo_{13-x}Fe_{x} 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. La_{0.9}Pr_{0.1}Co_{9}Fe_{4} has the largest value 29μ_{B}/f.u.

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.

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