e+e-湮没中轻夸克碎裂为粲介子的研究

研究了e+e-湮没中"初始"轻夸克和胶子劈裂产生的组合为介子(包括D-, D-s, 0)或*介子(包括D*-, D*-s, *0)的过程.发现尤其在s=MZ处,其产额相对较大,当限制或*的能量大于20GeV时,它和c夸克碎裂产物的不变质量谱在稍大于2M附近有一个峰,这是该过程区别于其它或*介子产生过程的显著特征.此过程产生的矢量介子基本上是纵向极化的,与实验上观测到的*介子的纵向极化一致.     

Spatial beam shaping by quartz crystal piano-convex lens

Based on the optical activity of quartz crystal, we proposed a scheme for shaping the spatial intensity distribution of a linearly polarized laser beam by utilizing a quartz crystal piano-convex lens in combination with a polarizer. The intensity profile of the shaped laser beam can be easily switched from one profile to another by controlling the polarization direction of the incident laser beam.     

Formation mechanism of ordered stress-relief patterns in a free sustained Cu film system

A nearly free sustained copper （Cu） film system has been successfully fabricated by thermal evaporation deposition of Cu atoms on silicone oil surfaces, and a characteristic ordered pattern has been systematically studied. The ordered pattern, namely, band, is composed of a large number of parallel key-formed domains with different width w but nearly uniform length L; its characteristic values of w and L are very susceptible to the growth period, deposition rate and nominal film thickness. The formation mechanism of the ordered patterns is well explained in terms of the relaxation of the internal stress in the films, which is related to the nearly zero adhesion of the solid-liquid interface. By using a two-time deposition method, it is confirmed that the ordered patterns really form in the vacuum chamber.     

液相基底温度对沉积银原子及其团簇凝聚过程的影响

研究了沉积银原子及其团簇在液相基底(硅油)表面的凝聚过程随基底温度的变化关系.实验结果表明:当硅油基底温度升高时,沉积银原子及其团簇的凝聚过程仍基本符合二阶段生长模型; 样品具有明显的边缘效应,在样品中心区域,凝聚体的覆盖率比边缘的相应值小,样品中心区域的凝聚体覆盖率先随薄膜名义厚度的增加迅速增大,然后逐渐趋于饱和,覆盖率趋于饱和时的膜厚值随基底温度的升高而降低; 对于一定的薄膜名义厚度,硅油基底温度越高,中心区域的凝聚体覆盖率越小.银原子凝聚体的分枝平均长度随基底温度的演化过程也具有类似的规律.对沉积银 关键词： 薄膜 液相基底 分枝状凝聚体 生长模型     

镀镍光纤Bragg光栅温度传感特性实验研究

在光纤智能金属结构材料中,为了保护光纤Bragg光栅并使得传感器与基体金属有很好的结合性,在光纤Bragg光栅表面化学镀镍,并实验研究了化学镀镍前后的光纤Bragg光栅的温度传感特性.实验表明：镀镍后的光纤光栅的Bragg波长随温度变化呈现出良好的线性和重复性,Bragg光栅温度灵敏度变大.     

LaFe1－xCrxO3系列氧化物的EXAFS研究

采用固相反应法, 制备了钙钛矿结构氧化物LaFe_1－xCr_xO₃较宽范围内(x=0.0—0.7)的系列单相样品, 并测量了各样品的X射线衍射谱(XRD)和扩展X射线吸收精细结构(EXAFS)谱. 通过对XRD的分析样品均为钙钛矿结构正交相, 同时晶格常数随着掺杂量x的增加而减小. 通过对EXAFS的分析和研究得到在LaFe_1－xCr_xO₃氧化物中Fe-O键长和Fe-La键长随掺杂浓度x的变化, 发现Fe-La键长发生比较大的变化, 说明La在体系掺杂中对结构的稳定起到重要作用.     

A Novel Model of Interaural Time Difference Based on Spatial Fourier Analysis

Based on the spatial Fourier analysis, a statistical model of the individualized interaural time difference （ITD） is derived from the head-related transfer function database for a Chinese subject. The model reflects the spatial left-right symmetry and front-back asymmetry of lTD. Moreover, by using three anatomical parameters of head and pinna, the model is able to predict individualized ITD in the horizontal plane. Performance of the four subjects outside the database demonstrates that the mean of the total error is less than 20 μs, while the lateral performance is inferior to that at other directions.     

“有关矩阵正定性的几个不等式”中的一个错误

本文指出“有关矩阵正定性的几个不等式”一文中的一个错误,并给出修正结果.     

半圆透镜的加工

<正> 图1为半圆透镜的加工,原是将单块半圆透镜粘上火漆,上盘时将两块半圆透镜的弦面对成一近似圆透镜的形状,再贴置上盘,成盘精磨抛光。但当a、b两透镜进行胶合时,很难使中心偏C达到0.03mm的技术要求。有时中心偏虽然合格,但外圆柱面又会出现两块不齐的现象,因而造成大量报废。     

软强子反应的碰撞成份

本文指出, 软强子反应中的碰撞成份为价层子或结构层子时, 将导致显然不同的有效能量分布及碎裂重子动量分布. 在定量计算了共振衰变对这些分布的修正后, 给出了从这些实验分布直接判别碰撞成份的原理与方法. 并发现现有实验已明显支持碰撞成份是结构层子, 排除价层子.