同轴金纳米管有序阵列的光学特性及滤波应用

为实现超材料滤波器在可见和近红外波段的多波段可调滤波,通过时域有限差分法对同轴金纳米管有序阵列进行数值模拟,研究了该结构中圆柱形和间隙表面等离激元的吸收特性及其滤波应用,分析了共振波个数及波长位置与结构参数的关系.仿真结果表明,通过调节结构参数可以实现在600～1700 nm范围内多波段可调滤波.     

Natural Convection of Nanofluid in Cylindrical Enclosure Filled with Porous Media

A numerical study has been carried out to investigate the effect of aspect ratio on heat transfer by natural convection of nanofluid taking Cu nano particles and the water as based fluid. The flow is laminar, steady state, axisymmetric two-dimensional in a vertical cylindrical channel filled with porous media. Heat is generated uniformly along the center of the channel with its vertical surface remain with cooled constant wall temperature and insulated horizontal top and bottom surfaces. The governing equations which used are continuity, momentum and energy equations using Darcy law and Boussinesq＇s approximation which are transformed to dimensionless equations. The finite difference approach is used to obtain all the computational results using the MATLAB-7 program. The parameters affected on the system are Rayleigh number ranging within （10≤ Ra ≤ 103）, aspect ratio （1 ≤ As 〈 5） and the volume fraction （0 ≤0 〈 0.2）. The results obtained are presented graphically in the form of streamline and isotherm contour plots and the results show that as ~ increase from 0.01 to 0.2 the value of the mean Nusselt number increase 50.4% for Ra = 1,000.     

圆柱形螺旋压缩弹簧稳定性的模糊概率预测

根据模糊概率理论,对圆柱形螺旋压缩弹簧稳定性的模糊概率预测方法进行了探讨,并给出了实例     

圆柱形TLD-高层钢结构系统风振舒适度控制设计方法

研究了圆柱形TLD-高层钢结构系统的风振舒适度控制设计方法.给出了受控结构的风振加速度设计计算公式和风振舒适度控制设计步骤.算例表明,TLD对结构风振加速度的控制是十分有效的.     

界面滑移对圆柱形凹坑织构滑动轴承摩擦力的影响

为研究不同的滑移情况对圆柱形凹坑织构滑动轴承摩擦力的影响,建立含有圆柱形凹坑织构的滑动轴承在不同界面滑移状态下的摩擦力计算模型,探究影响织构化滑动轴承摩擦力的参数,并借助ANSYS分析不同滑移情况下界面滑移对圆柱形凹坑织构滑动轴承摩擦力的影响规律。结果表明:织构化滑动轴承的摩擦力主要是由轴颈线速度、油膜滑移比、轴承的进出油口压力、织构处油膜压力、织构深度、油膜厚度和承载力决定;不同滑移情况下织构模型的摩擦力均小于无织构模型;且在上下表面均滑移时,圆柱形凹坑织构在出口位置时表现出最优的承载和减摩效果;适当地增加圆柱形凹坑织构的深度可以改善模型的摩擦性能,但是过深的凹坑织构并不能发挥出其性能。     

圆柱形离子阱质谱仪关键技术研究及参数优化

采用EI电离源,研制了采用圆柱形离子阱为质量分析器的质谱仪,结合电子倍增管、小信号放大系统和数据采集卡,实现了离子的检测和数据采集,并通过LabVIEW控制整个系统。在真空系统中,优化了该质谱仪的灯丝电流、推斥极电压、背景气体压强及质量扫描速度等工作参数,并给出不同工作参数下谱峰的变化规律。使用优化后的参数对水杨酸甲酯进行检测,结果表明,该仪器性能良好,可以获得准确的有机物谱图信息,完成物质的质量分析。     

湿饱和混凝土抗侵彻性能分析

混凝土侵彻弹靶相互作用是一种剧烈的动力学过程,但现有空腔膨胀模型用于混凝土侵彻工程计算时,引用的靶材料参数全为混凝土的静态力学特性参数,这必然会导致理论计算结果与工程实际的偏离.为提高混凝土侵彻工程计算预估精度,依据湿饱和混凝土的SHPB试验结果,在柱形空腔膨胀模型的基础上,考虑混凝土的动态响应特性,进行湿饱和混凝土侵彻深度工程计算,结果表明,其抗侵彻性能略优于正常状态.     

不确定度至E-5量级的微牛级力值计量装置研究

微牛级力值的测量技术广泛应用于空间探测、生物材料分析与微纳制造等领域的研究。基于静电力天平原理,设计并搭建了一套用于微牛级力值测量的装置,针对前期研究中测量装置的铅垂向刚度过大和圆柱形电容器同轴度对准误差较大的问题,通过优化设计四边形柔性枢轴的结构降低了系统在铅垂向的刚度,提升了静电力天平的力值分辨力,并基于圆柱形电容器的电容特性实现了对内、外电极同轴度的校准。经过实验测量,设计的微牛级力值计量装置具备了将100μN力值的测量不确定度控制在E-5量级的能力。此项研究成果将为微牛级力值测量基准装置的建立和微牛级力值量传方法的研究做出重要贡献。     

Coupled hydroelastic vibrations of an elliptical cylindrical tank with an elastic bottom

An exact three-dimensional analysis based on the linear potential theory and the elaborated method of eigenfunction expansion in elliptic coordinates are presented to study the free coupled elasto-hyrodynamic characteristics of an upright non-deformable cylindrical container of elliptical planform with a flexible bottom plate, filled to an arbitrary depth with an inviscid incompressible liquid. Extensive numerical data are presented in an orderly fashion for the first few symmetric/anti-symmetric coupled hydroelastic natural frequencies as a function of fluid depth parameter for two plate aspect ratios. Also, selected hydrodynamic and structural deformation modes shapes are presented in graphical form. The effects of liquid level, bottom plate elasticity, and cross sectional aspect ratio on the sloshing frequencies and hydrodynamic pressure modes are examined. The validity of the results is examined through computations using a commercial finite element package as well as by comparison with the data available in literature.     

垂直激励圆柱形容器中的表面波结构

本文利用奇异摄动理论的两时间变量展开法，研究了垂直强迫圆柱形容器中的单一水表面驻波模式。假设流体是无粘、不可压且运动是无旋的，在忽略了表面张力的影响下，得到一个具有立方项以及底部驱动项影响的非线性振幅方程。对上述方程进行了数值计算，研究了特定(9，6)模式的表面驻波结构和特性，如驻波的节点分布及驻波随某些参数的变化规律等，从计算的等高线的图象来看，和以往的实验结果相当吻合。