Investigation of Locally Loaded Multilayer Shells by a Mixed Finite-Element Method. 2. Geometrically Nonlinear Statement

Based on mixed finite-element approximations, a numerical algorithm is developed for solving linear static problems of prestressed multilayer composite shells subjected to large displacements and arbitrarily large rotations. As the sought-for functions, six displacements and eleven strains of the shell faces are chosen, which allows us to use nonlinear deformation relationships exactly representing arbitrarily large displacements of the shell as a rigid body. The stiffness matrix of a shell element has a proper rank and is calculated based on exact analytical integration. The bilinear element developed does not allow false rigid displacements and is not subjected to the membrane, shear, or Poisson locking phenomenon. The results of solving the well-known test problem on a nonsymmetrically fixed circular arch subjected to a concentrated load and the problem on a locally loaded toroidal multilayer rubber-cord shell are presented.     

多层不均匀材料中光吸收系数深度分布计算的理论处理

提出了一种通过光热法测定与样品表面温度有关的光热信号，重构反映多层不均匀材料中光吸收系数深度分布的理论处理和新的有效数值计算方法，数值模拟显示了较好的逼近效果。     

Polarization Performance of a New Spectrometer Based on a Multilayer-Coated Laminar Grating in the 150-190-eV Region

We constructed a polarization spectrometer based on a laminar grating applied with a Mo/B₄C multilayer coating. The multilayer-coated grating had been previously evaluated to have high polarizance at around 6.7 nm (184 eV) due to the Brewster reflection. In this study the polarization spectrometer was found to be usable in a range from 150 to 190 eV. Using it, σ and π emission spectra in the B 1s emission from a CrB₂ single crystal were separately recorded for the first time in the soft x-ray region. The spectral feature of the emission was reasonably well reproduced by the band calculation.     

Effect of gas atoms on X-ray optical properties of multilayers

Multilayers always dissolve some gas atoms during sputtering. In this paper, we develop a new method to study the effect of gas atoms on X-ray reflectance of the multilayer. Our theoretical analysis shows that this effect depends not only on the content of gas atom but also on the wavelength and the grazing angle. The shorter the wavelength and the bigger the grazing angle, the stronger this effect of gas atoms. We fabricated Mo/Si multilayers under various sputtering pressures and measured their small angle X-ray diffraction spectra. The measured results coincide with those calculated by our method.     

多层介质膜的体吸收与界面吸收研究

以TiO_2/SiO_2膜系为例,报道了用横向光热偏转技术研究多层介质膜体、面吸收的实验方法与实验结果.文中对实验结果作了分析讨论并把它与文献报道的光声法作了比较.     

NONLINEAR STABILITY CRITERIA FOR MOTIONS OF MULTILAYER QUASI-GEOSTROPHIC FLOW

Some nonlinear stability criteria for motions of multilayer quasi-geostrophic flow on a beta-plane are obtained by combining Arnold's method with an accurate estimate method. The criteria can be applied to perturbations of initial data and parameters; rather than the former only. Particularly a criterion corresponding to Arnold's second theorem is gained, which relies on some precise analyses and estimates.     

半花菁／氮冠（醚）交替LB多层膜的二阶光学非线性性质

对一种新型的，具有双脂链的盘状非活性分子氮冠（醚）（ＮＣ）ＬＢ膜进行了表征。小角Ｘ射线衍射（ＳＡＸＤ）结果表明：纯ＮＣ分子可以形成非常好的ＬＢ膜有序结构。将它与活性分子半花菁（ＤＡＥＰ）制备成Ｙ型交替多层膜，由于半花菁分子的单脂链（长尾）可以镶嵌在ＮＣ分子的双脂链之间，改善了多层膜的结构有序性及稳定性，从而得到二次谐波强度随层数的变化在１￣１１６双层范围内显示出较理想的平方关系。通过二次谐波的测量     

节瘤缺陷对中红外高反射膜电场增强影响的数值分析

运用时域有限差分(FDTD)方法建立了薄膜中节瘤缺陷在高斯激光照射下电磁场响应模型，分析了节瘤的深度、起始颗粒大小和入射光角度对薄膜中电磁场的影响。结果表明：节瘤缺馅对薄膜中电场强度有显著的加强作用，其内部峰值场强是入射光的6倍，大而浅节瘤缺陷对倾斜入射p偏振态的激光具有最高的加强效应.     

Modelling self-assembling of colloid particles in multilayered structures

Simulations of particle multilayer build-up in the layer by layer (LbL) self-assembling processes have been performed according to the generalized random sequential adsorption (RSA) scheme. The first (precursor) layer having an arbitrary coverage of adsorption centers was generated using the standard RSA scheme pertinent to homogeneous surface. Formation of the consecutive layers (up to 20) was simulated by assuming short-range interaction potentials for two kinds of particles of equal size. Interaction of two particles of different kind resulted in irreversible and localized adsorption upon their contact, whereas particles of the same kind were assumed to interact via the hard potential (no adsorption possible). Using this algorithm theoretical simulations were performed aimed at determining the particle volume fraction as a function of the distance from the interface, as well as the multilayer film roughness and thickness as a function of the number of layers. The simulations revealed that particle concentration distribution in the film was more uniform for low precursor layer density than for higher density, where well-defined layers of closely packed particles appeared. On the other hand, the roughness of the film was the lowest at the highest precursor layer density. It was also predicted theoretically that for low precursor layer density the film thickness increased with the number of layers in a non-linear way. However, for high precursor layer density, the film thickness increased linearly with the number of layers and the average layer thickness was equal to 1.58 of the particle radius, which is close to the closely packed hexagonal layer thickness equal to 1.73. It was concluded by analysing the existing data for colloid particles and polyelectrolytes that the theoretical results can be effectively exploited for interpretation of the LbL processes involving colloid particles and molecular species like polymers or proteins.     

基于多层膜偏振元件的同步辐射光束线偏振特性测量研究

利用自行研制的同步辐射软X射线多层膜综合偏振测量装置, 对北京同步辐射装置(BSRF)的3W1B软X射线光束线的偏振特性进行了系统的研究. 给出了多层膜偏振元件起偏前后的测量结果, 测量能量为206eV时, 经反射镜、光栅等光束线光学元件后输出的线偏振度(起偏前)为0.585, 经多层膜偏振元件起偏后输出光的 线偏振度达到0.995.