多重网格技术与波恩迭代法 相结合的反演新方法

本文将多重网格技术与波恩迭代法(BIM)相结合,利用时域散射数据对二维无耗非均匀介质剖面进行了反演.在反演迭代过程中,待反演目标区域的离散网格由粗逐渐变细.由于在反演的初期,目标区域离散网格较粗,离散反演积分方程所得到的矩阵方程的维数较小、条件数较低,使得该方法具有稳定性好、更容易收敛到真解的特点.通过反演实例表明,该方法极大地降低了反演过程的计算量,与传统的BIM方法相比能更精确地反演高对比度的散射目标.更为重要的是本文方法简单可行、可以与其它任何反演方法相结合.     

一种新型非晶态分子材料的非线性光学折射率和吸收特性

用单光束扫描法测量了在532nm处一种新型非晶态分子材料5,5′Bis(dimesitylboryl)2,2′bithiophene的非线性折射率和吸收系数样品非线性透射特性的分析表明,在靠近线性吸收区的532nm处有饱和吸收存在由三能级饱和模型和Zscan法确定了饱和强度、非线性折射率的实部和虚部研究结果表明:这种新型非晶态分子材料具有非常好的光子学应用前景.     

Determination of strain and stress distribution on shearwalls by using the speckle photography technique

Speckle photography (SP) is a powerful tool that is adequate to determine small displacements in micrometer range. This information shows other characteristics of structure deformation under loads and can be determined as stress and strain distribution. In this paper we present the results of the application of the SP technique used to study the behaviour of discontinuities in a shearwall model. These structural elements are very important to the stability of buildings. The displacement whole field around the discontinuities and loading points was determined using the pointwise method. This allows us to determine stress distribution at the point of interest by means of the suitable equations. We also present the stress distribution obtained through the finite element method in order to compare the results obtained by means of these two techniques. Good correspondence was found between the displacements determined by both techniques (r=0.982) and also between the stress values we obtained.     

XeCl准分子激光对聚对苯二甲酸乙二酯的表面接枝改性

用XeCl准分子激光照射聚对苯二甲酸乙二酯 (PET)薄膜 ,并同时进行表面接枝 ,提高薄膜表面亲水性。研究了激光能量和脉冲次数对照射和接枝后PET薄膜表面亲水性的影响 ,对比了激光照射烧蚀和接枝薄膜的表面性质差异 ,并分析了激光照射和接枝后样品重量变化的影响因素 ,提出了一种新的接枝率计算公式     

等离子显示器(PDP)应用与发展

在参阅大量参考文献的基础上，详细地介绍了等离子显示器的工作原理、特点与发展概述，对我国发展等离子显示器也作出了比较明确的说明与分析。具有一定的参考价值。     

卫星通信系统对抗途径分析

本文在叙述了卫星通信系统组成的基础上，分析了卫星通信对抗系统的内容、应具有的功能和实现对抗的主要途径与方法，最后探讨了实现对抗所要解决的关键技术。     

非载气式激光同轴送粉试验研究

研制了一种非载气式激光同轴送粉系统，粉末流能汇聚输出，其焦点尺寸为φ1．5mm，焦距fp15～35mm连续可调。在二维平面上熔敷消除了方向性影响，多层激光熔敷组织、成分及硬度分布均匀。与载气式同轴送粉相比，具有较高的粉末利用率(60％-80％)及较高的工业应用价值。     

Nonlinear refraction measurements in presence of nonlinear absorption using phase object in a 4f system

We report a technique to measure the value of the nonlinear refractive index of materials in presence of nonlinear absorption using a phase object at the entry of a 4f coherent imaging system. We show that it is possible to obtain a signal approximately due only to the induced nonlinear refraction in presence of two photon absorption. Experimental and simulated Z-scan transmittance profiles with and without phase object, as well as acquired and calculated images are presented here in order to validate our approach. We show also that the use of a reference material simplifies the measurement procedure avoiding computer fits.     

SOLUTION OF A CLASS OF NONHOMOGENEOUS ELLIPTIC SYSTEM INVOLVING CRITICAL SOBOLEV EXPONENT

In this paper, we discuss the problem of solving a class of nonhomogeneous semilinear elliptic system with critical Sobolev exponent changing into one of critical points of some given functional. Using Nehari technique, the given functional attain its minimum by adding suitable constraints, and the minimal point becomes a critical point of the original functional after eliminating the added constraints, thus the solution of the nonhomogeneous elliptic system is obtained.     

RIBLL终端LASCAR闪烁体阵列探测器研制进展

介绍了RIBLL终端LASCAR闪烁体阵列探测器的工作原理和结构特点. 描述了为满足放射性核束实验的要求而对阵列所作的重要改进. 给出了LASCAR构型优化改造的工作设想和实施步骤. The principles and structure characteristics of LASCAR scintillator array detector at RIBLL terminal are described. Special emphases are laid upon the latest progress for the development of LASCAR array detector to meet the requirements of the RIB experiments. The working plan and steps for optimizing configuration of the LASCAR multi unit neutron scintillator array detector are also presented.