Reflection and transmission of an Airy beam in a dielectric slab

The reflection and transmission of a finite-power Airy beam incident on a dielectric slab are investigated by an analytical method. Based on the plane-wave angular spectrum expansion and Fresnel approximation, the analytical expressions of the reflected field, internal field as well as transmitted field in each region are obtained. Through numerical simulations, the intensity distributions of the incident beam, reflected beam, internal beam as well as transmitted beam are presented at oblique incidence. Besides, we also compare the intensity distributions of the geometrical-optics beam field, the first order beam mode field and the actual beam field, which indicates that the contribution of each order beam mode field to the actual beam field is related to the refractive index of the dielectric slab. Meanwhile, the reflection characteristics of the Airy beams in the special cases of Brewster incidence and total reflection are investigated. Finally, the effects of the optical thickness and refractive index of the dielectric slab on the peak intensity distributions and beam shifts of the reflected and transmitted beams are also discussed in detail. The analytical and numerical results will be useful to analyze the propagation dynamics of Airy beam in the dielectric slab and provide some theoretical supports to the design of optical film.     

自适应有源消声中的FMLMS算法研究及实现

因简便易行而在自适应有源噪声控制（AdaptiveActiveNoiseControl,简称AANC）中广泛应用的滤波-XLMS算法（简称FLMS算法）,由于其对输入向量自相关矩阵特征值分散程度的敏感性强,从而限制了它在AANC中的应用范围。木文提出了滤波-XMLMS算法（简称FMLMS算法）,是在原FLMS算法基础上增加了一个动量项。通过大量的理论分析、计算机仿真和实时实验,证明了该算法在单通道自由声场的AANC中有着比FLMS算法优越的性能。     

由活性大分子环状前体合成环状聚ε-己内酯接枝聚L-乳酸

由2,2-二丁基-2-锡-1,3-二氧环庚烷引发ε-己内酯开环聚合制得环状聚ε-己内酯(3);3与活性单体α-(1-丙烯酰氧乙基)-ε己内酯反应,合成了活性环状聚ε-己内酯(5);5在UV辐照下发生分子内交联反应制得活性大分子引发剂6;6引发L-丙交酯接枝共聚合制得环状聚ε-己内酯接枝聚L-乳酸,其结构经NMR,SEC和DSC表征。     

新型偶氮苯硫醇衍生物自组装膜的制备与结构表征

自组装单分子膜(ＳＡＭｓ)是近年来引起广泛注意的一种稳定的、二维有序的、致密的有机超薄膜体系,由于其优越的性能,在润滑、吸附、防腐、电化学及微电子等领域中显示出广阔的应用前景[1～4].自组装单分子膜是使用含有各种活性官能团(如-ＣＯＯＨ,-ＳＨ,-Ｓ-Ｓ-,-ＯＨ,-ＣＮ等)的分子,以化学键的形式与相应的基底(如Ａｕ,Ａｇ,Ｃｕ,Ｐｔ,Ｓｉ,Ｍｉｃａ等)相互作用从而自发地形成自组装膜.根据不同的研究或应用目的合理设计组装分子的结构及基底表面,从而得到具有所需功能的自组装单分子膜是近年来界面科学和材料科学等领域研究的热点之一.…     

甘油糖脂的UPLC-Q-TOF-MS研究

糖脂是植物光合膜脂的主要成分[1],在影响光合作用的效率[2-3]、帮助植物体适应生态条件的改变[4]等方面起着非常重要的作用,糖脂及其降解产物在抗肿瘤活性[5-6]及影响细胞凋亡、分化、衰老等方面的研究[7-9]现在也越来越深入,所以研究植物膜糖脂具有十分重要的意义.     

多复变量的Bα到BMOA的复合算子

本文研究了Bα(Bm)到BMOA(Bn)上的复合算子.利用Caxleson测度的等价条件,得到了Bα(Bm)到BMOA(Bn)上复合算子的有界和紧性的特征,推广了Bloch空间上复合算子的相应结果.     

Scattering from a Multi-Layered Sphere Located in a High-Order Hermite-Gaussian Beam

Scattering of a high-order Hermite-Gaussian beam by a multi-layered sphere is analyzed. The incident high- order Hermite-Gaussian beam field is expressed by the complex-source-point method and expanded in terms of spherical vector wave functions. The beam shape coefficients of the Hermite-Gaussian beam are obtained. Under electromagnetic field boundary conditions, coefficients in the expressions of scattering fields are derived. Results of the numerical calculation of scattering intensity are presented. The effects of the particle parameters and beam parameters on scattering intensity are discussed in detail.     

通过力学教学实现中学物理到大学物理的良好过渡

如何完成由中学物理到大学物理的过渡性教学,是每位大学物理教师必须思考的普遍性问题。作者通过分析学生由中学物理向大学物理过渡学习出现的问题,及对大学物理教育目标的剖析,提出大学物理教学关键是要充分认识大学物理教学目标,并围绕该目标,实施大学物理教学过程,即教学要在系统性和方法论上下工夫。鉴于力学部分在大、中物理中的重要地位,结合力学教学实践,总结出通过力学教学实现中学物理到大学物理良好过渡几点体会。     

互联网+背景下近代物理教学实践研究

"互联网+"背景下,传统课堂教学模式已经无法满足教与学的需求,使用多元化教学手段和模式已经成为高校教育工作者不断探索和研究的问题。基于"互联网+"网络环境的全方位的教学手段为学生提供多元化的学习途径,不但可以提高学生的自主学习能力,又可以培养学生研究问题的能力,为学生将来做研究工作奠定基础。