Nonaxisymmetric Vibrations of Discretely Reinforced Inhomogeneous Multilayer Cylindrical Shells under Nonstationary Loads

The equations of nonaxisymmetric vibrations of discretely reinforced multilayer cylindrical shells are analyzed. A refined Timoshenko model of shells and beams is used to analyze elements of an elastic structure. The vibration equations for an inhomogeneous elastic system are derived using the Reissner variational principle. The numerical solver of the dynamic equations is based on the integro-interpolation method used to construct finite-difference schemes for equations with discontinuous coefficients. The dynamic behavior of a five-layer cylindrical shell under distributed nonstationary loading is analyzed     

The unsymmetrical bending of cantilever rectangular plates

This paper discusses the problems of the unsymmetrical bending of cantilever rectangular plates under various loads by the energy method. We illustrate numerous calculating examples such as the plates which are subjected by the concentrated forces or concentrated couples unsymmetrically on free sides and corner points and by a uniformly or nonuniformly distributed loads unsymmetrically on free edges and so forth.     

Dimensional instabilities of polyester and polyolefin films as origin of delamination in laminated multilayer

Polymer–metal multilayer films provide attractive barrier properties to air and water, provided by several films bonded together. Used in high temperature and humidity, the delamination is the most common degradation mechanism. This mode of failure is critical because it leads to premature loss of barrier properties. Therefore, delaminations limit the use of multilayer in these conditions. Delamination should result from interfacial shear stress, and plausibly from difference of shrinkage of the films, due to relaxation of internal stress. A method was developed for measuring the deformations of each individual film. The measurements indicate that the shrinkage is anisotropic and controls the decohesion in the multilayer. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 309–319     

Molecular dynamics simulation of nano-indentation on Ti-V multilayered thin films

We developed a second nearest-neighbor modified embedded-atom method potential for binary Ti-V system. The potential parameters were identified by fitting the lattice parameter, cohesive energy and elastic constants of CsCl-type TiV, and further validated by reproducing the fundamental physical and mechanical properties of Ti-V systems with other crystal structures. In addition, we also performed molecular dynamics simulations of nano-indentation processes of pure Ti film, pure V film, and two kinds of four-layer Ti-V films, V-Ti-V-Ti and Ti-V-Ti-V. We found that the indentation force-depth curve for the pure V film turns flat at an indentation depth of 2.8 nm, where a prismatic loop was observed. Such prismatic loop is not found in the V/Ti/V/Ti multilayer because the thickness of each layer is insufficient for the formation of such prismatic loops, which accounts for the increase of stress in the multilayer.     

调幅W(Mo)/Cu纳米多层膜He+离子辐照响应行为

用磁控溅射技术制备不同调幅波长 (L) 的W(Mo)/Cu纳米多层膜,所制膜系在60 keV氦离子 (He⁺) 辐照条件下注入不同剂量: 0, 1×10¹⁷ He⁺/cm², 5×10¹⁷ He⁺/cm². 用X射线衍射仪 (XRD) 和高分辨透射电子显微镜(TEM)表征W(Mo)/Cu纳米多层膜辐照前后微观结构. 研究结果表明: 1) He⁺离子轰击引起温升效应是导致沉积态亚稳相β-W 转变成稳态 α-W相的主因, 而与调幅波长无明确关联; 2) 纳米多层结构中W(Mo) 和Cu膜显现出的辐照耐受性与调幅波长相关, 调幅波长越小, 抗He⁺的辐照性能越强; 3) 在5×10¹⁷ He⁺/cm²注入条件下, 观察到He团簇/泡在纳米结构W(Mo) 和Cu膜中的积聚行为存在明显差异: 在W (Mo) 膜中He团簇/泡的分布与晶粒取向相关, He团簇/泡倾向于沿W (211) 晶面分布; 而Cu膜非晶化且He团簇/泡在其体内呈均匀分布. 关键词： W(Mo)/Cu纳米多层膜 +辐照')" href="#">He⁺辐照 He团簇/泡 相转变     

Distortion of a simple Gaussian beam on reflection from off-axis ellipsoidal mirrors

We examine the distortion of a simple linearly polarised Gaussian beam on reflection from an off-axis ellipsoidal mirror. Expressions are derived for the distorted reflected fields and for the loss of power into higher order and cross-polarised modes.     

SCANNING AUGER ELECTRON SPECTROSCOPIC INVESTIGATIONS OF MAGNETOSTRICTIVE NANOSCALE MULTILAYERS

The characterisation of thin magnetostrictive multilayers in the nanometerscale range [(4,5nmTb₄₀Fe₆₀/9nmFe)×100] demands a surface sensitive analytical technique. A suitable technique is scanning Auger Electron Spectroscopy (AES) to determine the elemental composition, the thickness, the presence of interdiffusion between thin layers, or the presence of contamination at interfaces.Auger sputter depth profiles are obtained by using Xe-Ion bombardment to etch the sample.Sample rotation during sputtering produces shallow craters, minimises roughening and enhances depth resolution. In addition, Auger maps of the craters are used to reveal the separated magnetostrictive Tb₄₀Fe₆₀ layers and soft magnetic Fe layers.     

多层介质光学膜系的计算机模拟误差分析

用计算机数值计算方法模拟多层介质光学膜系的实际镀膜工艺过程，分析膜厚误差对λ0／4高反射膜系透射率和反射率的影响，讨论在一定技射率要求条件下不同层数膜系的允许厚度误差。发现当膜层偏离λ膜厚时，光学厚度控制工艺能通过自动调整其后膜层的厚度有效地降低厚误差对膜系透射率和反射率的影响。对于镀制高反射率膜而言，膜厚允许误差仍可有较大的范围。     

Mo/Si多层膜在质子辐照下反射率的变化

为了检验应用在极紫外波段空间太阳望远镜上Mo/Si多层膜反射镜在空间辐射环境下反射率的变化情况, 模拟了部分空间太阳望远镜运行轨道的辐射环境, 利用不同能量和剂量的质子对Mo/Si多层膜反射镜进行辐照实验.辐照前后反射率测量结果显示,由于带电粒子的辐照损伤,质子辐照会使Mo/Si多层膜反射镜的反射率降低,且质子能量越低、剂量越大,对多层膜的反射率影响越明显. 当质子能量E=160keV,剂量＝6×10¹¹/mm²时,反射率降低4.1%;能量E=100keV,剂量=6×10¹¹/mm²时, 反射率降低5.7%;能量E=50keV,剂量=8×10¹²/mm²时,反射率降低10.4%. 用原子力显微镜测量辐照后Mo/Si多层膜反射镜的表面粗糙度比辐照前明显增加,致使散射光线能量逐渐增大并最终导致反射率的降低. 关键词： 质子辐照 Mo/Si多层膜反射镜 辐照损伤     

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。