电沉积法制备金属纳米线阵列膜的偏光特性

Metal nanowire array films were prepared by electrodepositing Cu, Ag, Ni, Co and Cu-Ag on porous anodic alumina film. Optical transmittance of both the porous anodic alumina film and metal nanowire array film was measured in the wavelength range of 400---2600 nm under an obliquely incident light. The experimental results show that metal nanowire array films exhibit a prominent polarization function. It was found that optical polarization properties can be improved by choosing suitable kinds of electrodepositing metal, controlling the shape and length of nanowire, and changing the incident angle.     

具有kgd拓扑结构的二维铅配位聚合物的合成、结构及性质研究(英文)

醋酸铅(Pb(Ac)2·3H2O)和咪唑乙酸(Hima)通过溶胶凝胶扩散合成二维配位聚合物[Pb(ima)2]n(1)的单晶。X-射线单晶衍射分析表明,晶体属于单斜晶系,P21/n空间群,晶胞参数为:a=0.8750(2)nm,b=5.1226(12)nm,c=13.292(3)nm,β=93.570(4)°,V=594.6(2)nm3,Z=2。配合物[Pb(ima)2]n是一个具有二维kgd拓扑结构的配位聚合物,二维层间又通过C-H…O氢键连接形成三维超分子结构。对配合物的红外、元素、热重及荧光等性质进行了研究。     

烟尘簇团粒子光学截面和散射矩阵的数值计算

用离散偶极子近似方法，计算了单个烟尘簇团粒子的光学特性，得到了簇团粒子的散射截面、吸收截面及不对称因子随入射角的变化关系，为研究波在烟尘粒子中的传输特性提供了有效的计算方法；给出了不同入射角情况下烟尘簇团粒子散射矩阵元素的角分布，为研究散射体的散射特性、极化特性以及散射体结构特性提供了一种理论方法. 关键词： 烟尘簇团粒子 散射矩阵 光学截面 DDA     

脉冲波在空间等离子体介质中传播的矩分析及其应用

根据随机介质波传播理论，开展脉冲波在星际空间等离子体介质中的传播特性的分析方法研究.在强起伏条件下，推导双频互相关函数的二阶矩和四阶矩方程，利用不同电子密度模型，计算双频衍射强度相关函数和闪烁指数，并应用到闪烁的动态谱观测和相关分析中，得到自相关图谱、相关带宽和相关时间等闪烁特征参数，为脉冲在等离子体中的传输特性的分析，提供必要的理论基础.     

Time-Domain Scattering Modelling of Two-Dimensional Cylinder Located on a Rough Surface

Numerical modelling on the transient electromagnetic scattering by a two-dimensional （21）） cylinder located on a time-evolving rough surface is presented by using time-domain integral equations. The proposed special choice of a tapered Gauss pulse incident wave removes the truncation error from the rough surface. Additionally, a two-level averaging technique is utilized to overcome the instability from the time marching procedure of solving integral equations. Excellent correspondences between the surface current distributions, as well as the far-zone fields, computed by the proposed method and that obtained by the traditional method of moments associated with the inverse discrete Fourier transformation scheme demonstrate the accuracy of the modelling.     

基于靶面温度测量的激光强度时空分布重构方法

基于靶面温度分布测量反演激光强度时空分布的重构表达式中,被积函数包含的奇异阿贝尔核函数导致了求解积分表达式的病态和解的不稳定。为了解决这一积分求解问题,基于广义函数理论和正则变换方法,对积分函数进行了重新构造,获得了基于靶面温度时空分布测量反演入射激光强度分布的重构算法,并分析了重构结果对温度测量误差的敏感性。借助数值模拟方法对重构算法进行了验证,数值计算给出了重构强度误差与靶板厚度和辐照时间的关系。验证结果表明,两种背光面边界条件下反演获得的激光束时空分布,不仅与原始模型激光束达到了较好的一致,而且不受薄板条件的限制。算法对强激光辐照效应的靶面激光参量监测有实用性。     

Temporal broadening of pulsed waves propagating through turbulent media

Pulse signals, propagating through a turbulent medium such as the ionosphere, can be distorted by dispersion and scattering from both the background medium and irregularities embedded in. Thus, the mean square pulse width is changed, and temporal broadening is introduced. We carry out a study on the temporal broadening with theoretical analyses and numerical simulations by using an analytical solution of two-frequency mutual coherence function obtained recently by iteration. As a case of study, pulse broadening is investigated in detail in trans-ionospheric propagation. Results show that most contributions are mainly from the dispersion of the background ionosphere and scattering effects of electron density irregularities in most cases.     

Partially coherent Gaussian–Schell model pulse beam propagation in slant atmospheric turbulence

Based on the extended Huygens-Fresnel principle, a two-frequency, two-point cross-spectral density function of partially coherent Gaussian-Schell model pulse （GSMP） beam propagation in slant atmospheric turbulence is derived. Using the Markov approximation method and on the assumption that （w1 - w2）/（w1 ＋ w2） ≤ 1, the theory obtained is valid for turbulence of any strength and can be applied to narrow-band signals. The expressions for average beam intensity, the beam size, and the two-frequency complex degree of coherence of a GSMP beam are obtained. The numerical results are presented, and the effects of the frequency, initial pulse width, initial beam radius, zenith angle, and outer scales on the complex degree of coherence are discussed. This study provides a better understanding of the second-order statistics of a GSMP beam propagating through atmospheric turbulence in the space-frequency domain.     

高斯谢尔光束通过湍流大气漫射目标的散射统计

基于广义惠更斯菲涅耳原理分析了高斯谢尔光束通过湍流大气漫射目标的散射统计特性。假定相位结构函数起主导作用,根据高斯谢尔光束的交叉密度函数,推导了散斑场的互相干函数表达式,进而得出接收面处的散斑尺寸大小和强湍流起伏的时延协方差函数表达式。数值分析了源相干长度、波长、湍流强度对互相干函数的影响。对理想漫射目标,接收面的散斑尺寸大小由束腰宽度、源相干长度和湍流强度确定,随着湍流强度的增加,散斑尺寸变小;在弱湍流区,散斑尺寸由源相干长度决定,当湍流增强时,散斑尺寸大小逐渐趋于一致。     

掺杂对随机取向团簇粒子辐射特性的影响

利用Bruggeman有效介质理论得到了占有不同体积份额杂质的团簇粒子的等效复折射率.采用离散偶极子近似方法对包含有不同化学成分的随机取向团簇粒子的散射相函数、消光、吸收、散射效率因子、单次散射反照率以及不对称因子等辐射特性参量进行了数值计算,深入探讨了掺杂量对随机取向团簇粒子辐射特性的影响.研究表明,掺杂对随机取向团簇粒子的辐射特性产生显著的影响,并且此影响随着粒子尺度参量的变化而变化.这一工作对研究多种化学成分组成的混合气溶胶的辐射及气候效应具有重要科学价值.