一类对称三对角矩阵的合同对角化算法的实现

从一个对称三对角矩阵的合同变换出发 ,阐述了对称三对角矩阵对应的二次型标准化的一种方法 .     

高应变率下U-Nb合金的断裂组织特征

利用内部爆炸加载方法对U-Nb合金进行爆破试验，对爆破试验产生的破片进行回收，并对U-Nb合金破片进行一些微观检测分析，从而初步研究在爆炸加载下U-Nb合金的微观断裂机制。     

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.     

多官能团分枝状化合物的合成研究 Ⅳ.三方向醚-酰胺键型分枝状大分子的合成

本文报道三方向醚-酰胺键型多官能团分枝状大分子(Cascade)的合成.目标化合物以甘油、硝基甲烷为三方向起始核心,以从季碳原子三倍对称分散的化合物1～3为分支侧链.通过醚键进行空间延伸,以酰胺键进行分枝连接,经过一代或两代,所合成的分枝状大分子的末端官能团数是原起始核心的三倍或九倍.本文可为进一步的分枝反应提供基本的设计合成方法.     

物理实验的结果表示应采用不确定度新概念

科学研究及工业、商业活动都须进行大量测量工作．对测量结果的质量及测量技术水平高低的正确评价国内外都已用不确定度来表示．1978年以来，国际计量大会（CIPM）以及四个国际组织——国际标准化组织（ISO）、国际电工委员会（IEC）、国际法制计量组织（OIML）、国际计量局（BIPM），经过10多年的共同努力，终于对国际计量局提出的《实验不确定度的规定建议书INC—1（1980）》制定了协调的、具有国际指导性的《测量不确定度表达指南》．[1][2]1992年发表的指南的一些基本概念是国际和国内各界表达不确定度的最具权威性和指导性的…     

负动量压缩因子的环形对撞机磁聚焦结构的研究

探讨了设计负动量压缩因子(α_p<0)的正负电子对撞机储存环磁聚焦结构的可行性及方法.作为应用实例,说明了设计α_p<0的τ–粲工厂磁聚焦结构的可能性.