多小波子空间上的单小波表示

本文在较弱的条件下,建立了2重多小波子空间与单小波子空间的关系.即由2重多小波构造出单小波.一方面,这种单小波的平移伸缩与2重多小波的平移伸缩生成的子空间是完全相同的;另一方面,它具有插值性.因此通过构造出的单小波建立了多小波子空间上的Shannon型采样定理.     

金纳米粒子光学性质中的尺寸和形状效应

纳米尺度的金属及半导体呈现出特殊的光学、电学及磁学性质,采用近年发展起来的离散偶极近似(DDA)的方法,我们分析了金纳米粒子的尺寸及形状对其光学性质的影响。粒子周围介质的影响在文中亦作了分析。计算结果显示,金纳米粒子的等离子体吸收带同时受到粒子尺寸和形状的影响,但来自形状的影响更为明显。与米氏理论及扩展的甘氏理论相比较,DDA方法在粒子尺寸不再远小于入射光波长的时候更准确,并能应用于任何形状的纳米粒子。理论计算与实验结果能较好的吻合。     

ZrO2纳米粉等离子喷涂层组织与性能

用纳米结构粉末做喂料进行喷涂，缩短了颗粒熔化时间，在有限的飞行时间内，颗粒熔化效果更好，从而制备的涂层孔隙率更小，表面更平整。用ZrO2纳米结构喂料制备了等离子喷涂层，研究了功率、粒度、氧化钇含量等工艺参数条件下涂层的微观组织、孔隙率、相组成及抗热震性能。经X衍射分析表明，原始粉末由m-ZrO2,t-ZrO2,c-ZrO2构成，单斜相的含量为11％，主要由四方相和立方相构成。     

Nanoporous Structure in Low-Dielectric Films with Positronium Annihilation Lifetime Spectroscopy

We investigate nano-porous structures in thin low-dielectric films, i.e. the pore sizes, distributions, and interconnectivity, by using depth profiled positronium annihilation lifetime spectroscopy (PALS). It is found that PALS has good sensitivity to probe both interconnected and closed pores in the range from 0.3nm to 3Onto, even in the film buried beneath a diffusion barrier. A series of low dielectric constant films of organosilicon-silsequioxane with different weight percentages of porogen have been comparatively investigated. The PALS technique can be used to distinguish the open porosity from the closed one, to determine the pore size, and to detect the percolation threshold with the increasing porosity that represents the transition from closed pores to interconnected pores.Furthermore, the pore percolation length can be derived.     

Boundedness of Multilinear Operators on Herz Type Spaces： Extreme Cases

In this paper, two classes of closely related multilinear singular and fractional integrals,which include the commutators as special cases, are studied and their boundedness on Herz type spaces is discussed. In fact, it is proved that these operators are actually not bounded in certain extreme cases.     

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.     

模拟纳米晶体原子分布及X射线散射理论图案

通过分子动力学方法模拟纳米晶体（1—3nm）的结构．利用模拟的结果，进行了X射线衍射及径向分布函数的模拟计算．结果表明：纳米晶体晶界呈短程有序，界面原子间距分布很宽；随着晶粒尺寸的减小，晶粒的畸变越大，原子体积常数也明显增大 关键词：     

SiC多型体X射线定量分析的Rietveld方法

鉴于ＳｉＣ多型体的主要衍射线完全重叠，用常规Ｘ射线粉末衍射方法确定ＳｉＣ陶瓷材料中多型体含量的分布是非常困难的，提出以Ｘ射线粉末衍射全谱拟合的Ｒｉｅｔｖｌｄ方法进行ＳｉＣ多型体定量分析，阐述了原理及方法，对含３Ｃ，４Ｈ，６Ｈ和１５Ｒ４种多型体衍射数据的定量分析结果表明，Ｒｉｅｔｖｅｌｄ方法可对ＳｉＣ材料中常见多型体的定量分析给出准确的结果，还给出了各自的标准偏差，并估计了该方法对各多型体能给出精确     

Fe2O3纳米微粒溶胶非线性光学特性的Z-扫描研究

利用Z扫描技术在透明区域研究了Fe₂O₃纳米微粒水溶胶和表面包覆有机溶胶的非线性光学特性，给出了非线性折射率γ、双光子吸收系数β、自由载流子折射系数σ_r和自由载流子吸收截面σ_ab等重要物理参数，讨论了自由载流子效应对Fe₂O₃纳米微粒非线性特性的影响 关键词：     

Zn0.76Cd0.24Se/ZnSe多量子阱的共振喇曼光谱

本文报道了在Zn0.76Cd0.24Se/ZnSe多量子阱(MQWs)中,用不同的Ar+激光线激发,观察到了共振增强的喇曼散射。首次在室温和77K的条件下,用Ar+的457.9nm谱线激发,观察到分别来自ZnSe垒层和Zn0.76Cd0.24Se阱层的限制纵光学声子模(LO)的喇曼散射,并对上述不同的光学模的起因进行了分析。