Spin-Polarized Tunnelling Magnetoresistance Effects in La0.833K0.167MnO3／SrTiO3 Polycrystalline Perovskite Manganites

A sample of La0.833K0.167MnO3-SrTiO3 (LKMO/STO) is fabricated by the sol-gel method. The microstructure,magnetic and transportation properties have been studied. X-ray diffraction patterns indicate that the structure of LKMO/STO is a homogeneous solid solution phase. The resistivity of LKMO/STO shows the insulator behaviour, which is different from La0.833K0.167MnO3 (LKMO) whose resistivity shows metal-insulator transition with decreasing temperature. The low-field (moH = 0.02 T) magnetoresistance decreases from 11% to 0.2% with the increasing temperature from 4 K‘to 220K for the LKMO/STO sample. The magnitude of magnetoresistance in a strong field (μoH = 5.5 T) almost increases linearly with decreasing temperature and reaches the maximum of 65% at the low temperature of 4.2K, which is much higher than that oE LKMO (40%). The enhanced low-field magnetoresistance effects are quantitatively explained by the spin-polarized tunnelling at grain boundaries.     

Magnetic and Crystalline Microstructures of Fe-Pt-B Nanocomposite Ribbons

We investigate magnetic and crystalline microstructures of melt-spun (Fe0.675Pt0.325)100-xBx (x=12, 14, 16, 18,20) nanocomposite ribbons after optimal thermal treatment using a magnetic force microscope. The magnetic microstructures are characterized by darker spots adjacent to brighter ones in a sub-micro scale and in random distribution. It is found that the strength of the exchange coupling interaction between the crystals in the 10-100 nm scale, implied by the maximum value (δM)max of the Henkel plot, could be roughly described by the ratio of the average width of the magnetic spots w^- to the average crystal size D^- for the ribbons. Moreover, we find that the intrinsic coercivity jHc of the ribbons is sensitive to their crystal sizes, and the smaller D^-, the higher jHc. Finally, by using roughness analysis, the curve of the root mean square values (δФ)rms of the phase shift of the magnetic force images versus the boron content x is obtained, which is qualitatively consistent with that of the magnetization σ12 kOe of the ribbons versus x.     

Theoretical Study on the Rotational Bands and Shape Coexistence of^179，181，183Au in the Particle-Triaxial-Rotor Model

We perform a series of theoretical calculations and investigation for nuclei 179，181，183Au in the particle-triaxialrotor model with variable moment of inertia. The calculated energy spectra in^179,181,183Au agree well with the experimental data globally. The obtained results indicate that the nuclei^179,181,183Au have prolate deformation and involve shape coexistence with different deformation parameters in different bands. The main configuration of bands 1, 2, 3 and 5 in these nuclei are identified as [541]1/2^- (πh9/2, α = 1/2), [541]1/2- (πh9/2, α= -1/2),[530] 1/2- (πf7/2) and [660] 1/2^ (πi13/2), respectively.     

核介质中五夸克奇特重子态Θ+的有效质量

利用非线性s-w-r模型，在相对论平均场近似下，通过能量密度函数，给出了五夸克奇特重子态Q+有效质量随核密度的增加逐渐下降的依赖关系，并进行了数值计算.分析了不同参数对核物质中Q+有效质量的影响，并考虑了耦合系数中GQ/B的3个不同值，计算了不同耦合系数对Q+有效质量的影响.     

THE RELATIONSHIP BETWEEN PROJECTIVE GEOMETRIC AND RATIONAL QUADRATIC B-SPLINE CURVES

For two rational quadratic B-spline curves with same control vertexes, the cross ratio of four eollinear points are represented; which are any one of the vertexes, and the two points that the ray initialing from the vertex intersects with the corresponding segments of the twocurves, and the point the ray intersecting with the connecting line between the two neighboring vertexes. Different from rational quadratic Beeier curves, the value is generally related with the loeation of the ray, and the necessary and sufficient condition o5 the ratio being independent of the ray‘s loeation is showed. Alsn another cross ratio o5 the following four collinear points are suggested, i.e. one vertex, the points that the ray from the initlal vertex intersects respectivdy with the curve segmentt the line connecting the segments end points, and the line connecting the two neighboring vertexes. This cross ratio is concerned only whh the ray‘s location, butnot with the weights of the curve. Furthermore, the cross ratio is projective invariant under the projective transformation between the two segments.     

}MSo浸种对大麦种子萌发及若干性状的影响

本文报道二甲亚矾(DMSO)浸种影响大麦“早熟3号”种子的萌发以及浸种后种子的渗漏和呼吸强度等的变化.结果表明:在24℃条件干浸种，。.1%和5芳的DMSO明显促进种子的萌发，5劣DMSO浸种的促进作用尤为明显.然而这种影响效应在zs c条件下浸种则完全相反，对种子萌发有抑制作用，表现明显的温度效应.     

法沃尔斯基（FavorskiiAE）重排新进展

本文介绍了近年来法沃尔斯基重排反应在手性药物，立方烷系，杂环衍生物环烷小合成中的最新动态有应用前景。