铝粉快速反应光谱中AlOB~2Σ~＋→X~2Σ~＋发射光谱的研究

在由光学多道分析仪收集的氢氧气体爆轰激励下铝粉快速反应光谱中，观察到ＡｌＯＢ２Σ＋→Ｘ２Σ＋跃迁Δｖ＝０带系的光谱特征与通常铝氧化反应的光谱特征不同。经分析是因为存在一个从４６７ｎｍ开始向长波方增强的连续辐射，它改变了该波长区ＡｌＯ分子的辐射特征。这一连续辐射可能是由铝与水蒸汽发生水合反应生成，而处于不同激发态的多原子分子ＨＡｌＯＨ产生

剪切带状分叉的力学条件

在已论证过的应变软化效应对形成剪切带状分叉的作用的基础上,本文研究了:(1)什么受力情况最易激发剪切带(2)采用什么力学模型和参数可以模拟材料中的曲线型带状分叉。

第3届全国复合材料学术会议

<正> 会议于1984年11月2—7日在杭州举行,由中国宇航学会、中国航空学会和中国力学学会共同主办,全国科研、设计、生产部门和大专院校13个学院87个单位的221名代表参加了会议,大会收到学术报告312篇,接受了182篇,会前即预印了论文集,120篇论文分别在材料工艺、性能测试与应用、静动态力学性能、结构设计分析以及金属基复合材料五个组

Numerical Simulation of R-M Instability

In order to capture shock waves and contact discontinuities in the field and easy to program with parallel computation a new algorithm is developed to solve the N-S equations for simulation of R-M instability problems. The method with group velocity control is used to suppress numerical oscillations, and an adaptive non-uniform mesh is used to get fine resolution. Numerical results for cylindrical shock-cylindrical interface interaction with a shock Mach number Ms=1.2 and Atwood number A=0.818, 0.961, 0.980 (the interior density of the interface/outer density p(1)/p(2) = 10, 50, 100, respectively), and for the planar shock-spherical interface interaction with Ms=1.2 and p(1)/p(2) = 14.28are presented. The effect of Atwood number and multi-mode initial perturbation on the R-M instability are studied. Multi-collisions of the reflected shock with the interface is a main reason of nonlinear development of the interface instability and formation of the spike-bubble structures In simulation with double mode perturbation vortex merging and second instability are found. After second instability the small vortex structures near the interface produced. It is important factor for turbulent mixing.

冲击载荷作用下容器壳体动态响应的初步数值研究

本文针对带椭球封头的爆炸容器,黑索今(RDX)在中心处的爆炸用点爆炸模型描述,利用四阶Runge-Kutta法求解一组常微分方程得到爆炸近场的自相似解。采用有限体积形式的PPM格式求解轴对称Euler方程,得到了容器内冲击波传播及其演化的图象。以计算得到的冲击载荷为基础,修改HONDO程序,壳体弹塑性模型采用J_2流动理论描述。对冲击波和壳体的耦合作用进行了初步的数值研究。计算结果表明:容器内爆炸冲击波和壳体中应力波的传播及其演化与物理上的定性分析结果是一致的。由于应力波传播速度较冲击波快,因此,在冲击波未到达的静止流场,流场出现扰动声波,并向中心传播。封头顶点附近出现最大变形。在中等载荷作用下,可忽略壳体变形对流场的影响。

Adiabatic shear localization: occurrence, theories, and applications

溶菌酶晶体生长过程中的扩散传质问题

采用Mach-Zehnder干涉测量系统与图象处理系统相结合实时观测溶菌酶蛋白质晶体生长过程中的流体动力学现象,对汽相扩散法溶菌酶蛋白质晶体生长过程进行了研究,观测到溶菌酶晶体生长时晶体周围存在的干涉条纹.分析了晶体生长时的重力沉降效应和溶质扩散过程.实验结果表明,该生长过程中的流体物理特征直接影响了生长晶体的晶面.根据实验结果,给出对蛋白质晶体生长过程流体物理现象的讨论。 

Alignment of nanoparticles formed on the surface of 6H-SiC crystals irradiated by two collinear femtosecond laser beams

Nanoripples with periods of 150 and 80 nm are formed on the surface of 6H-SiC crystals irradiated by the p-polarized 800 nm and the s-polarized 400 nm femtosecond lasers, respectively. When both of the two collinear laser beams focus simultaneously on the sample surface, nanoparticles are formed on the whole ablation area, and they array in parallel lines. We propose and confirm that the second harmonics in the sample surface excited by the incident lasers plays an important role in the formation of nanostructures.

大口径八边形钕玻璃片支撑系统的光机集成分析

控制由机械装夹方式所引入的波前畸变以提高惯性约束聚变(ICF)输出光束的质量，是在大口径钕玻璃片主放大器结构设计中必须考虑的。提出了一种新的有限元变形结果与光学元件面形畸变之间的数据处理方式，并与传统方式进行了对比。基于新的数据处理接口，利用光机集成分析方法对大口径八边形钕玻璃片的支撑系统结构设计参数进行优化。优化的结果保证了由支撑系统引起的透过波前畸变小于十分之一波长，同时波前畸变与设计参数变动的相关性最小。

Fabrication and amplified spontaneous emission spectrum of Er3+-doped tellurite glass fiber with D-shape cladding

Tellurite glass is proposed as a host for broadband erbium-doped fiber amplifiers because of their excellent optical and chemical properties. A single-mode Er3+-doped tellurite glass fiber with D-shape cladding was fabricated in this work. The characterization of amplified spontaneous emission (ASE) from this newly fabricated Er3+-doped tellurite fibers are exhibited. When pumped at 980 nm, a very broad erbium ASE nearly 150 nm around 1.53 mum is observed. The changes in ASE with regard to fiber lengths and pumping power were measured and discussed. The output of 2 mW from Er3+-doped tellurite fiber ASE source was obtained under the pump power of 660 mW. The broad 1.53 mum emission of Er3+ in tellurite glass fiber can be used as host material for potential broadband optical amplifier and tunable fiber lasers. (C) 2004 Elsevier B.V. All rights reserved.

光栅位移测量系统的误差自修正方法研究

文中介绍的误差自修正方法是通过光栅位移测量系统中单片机对光栅传感器的多个零位信号进行计数,并根据测量值和系统设定值得到的误差函数自动进行误差修正。实验结果表明,该方法对光栅位移测量系统的误差既可自动进行有效的修正,又可提高系统的测量精度。