Surface waves in fibre-reinforced anisotropic elastic media

The aim of this paper is to investigate surface waves in anisotropic fibre-reinforced solid elastic media. First, the theory of general surface waves has been derived and applied to study the particular cases of surface waves — Rayleigh, Love and Stoneley types. The wave velocity equations are found to be in agreement with the corresponding classical result when the anisotropic elastic parameters tends to zero. It is important to note that the Rayleigh type of wave velocity in the fibre-reinforced elastic medium increases to a considerable amount in comparison with the Rayleigh wave velocity in isotropic materials.     

艺术改写中的审美取向和接受定位——基于张爱玲《半生缘》之多种叙述版本的表达

张爱玲的《半生缘》自创作至今,经历了从小说文本到影视、戏剧的多重改写。分析了不同创作主体面对时代和历史视野中的艺术资源所进行的审美性择取、融合及再创造,不同的叙述版本展现出了不同的审美取向和接受定位,从而给受众以多元的艺术感受。     

基于人工神经网络的乐甫波液体密度粘度并行检测研究

乐甫波器件负载液体时,液体的密度和粘度相互耦合,难以通过乐甫波器件直接实现其并行检测。基于上述背景,建立了基底与薄膜同时采用压电材料的双压电结构乐甫波器件液体传感理论模型,提出了基于人工神经网络的乐甫波液体密度粘度并行检测方法,以理论模型计算出的数据作为人工神经网络的训练数据,采用乐甫波的波速和衰减来并行预测液体密度和粘度,预测结果与理论仿真的对比表明了该方法的有效性。     

基于ZnO/AlN/金刚石温补结构的研究

使用COMSOL软件对ZnO/AlN/金刚石温度补偿结构进行建模分析,计算了该结构Love波模式0和模式1的频率温度系数(TCF)、声速(v)和机电耦合系数(k~2),且讨论了ZnO薄膜厚度h_(ZnO)和AlN薄膜厚度h_(AlN)对这些参数的影响。结果表明,当h_(ZnO)=1μm,h_(AlN)=1.88μm时,温度补偿结构Love波模式1的TCF=0,v=9 208 m/s,k~( 2)=3.84%,说明这种温度补偿结构能应用在高频和温度补偿声表面波器件中。     

界面缺陷对压电薄层复合结构中Love波的影响

基于剪切弹簧模型,建立考虑界面缺陷情形的弹性基底上覆盖压电薄层的复合结构中Love波的频散方程,并研究界面缺陷对Love波传播特性的影响,给出铝基底上覆盖PZT4压电薄层复合结构中Love波的频散曲线.数值结果表明:(1)对于长波情形,不同缺陷程度复合结构的Love波一阶模态的相速度均趋于弹性基底层的剪切波波速,而对于短波情形,则趋于压电薄层的Bleustein-Gulyaev(B-G)波波速;(2)界面缺陷的存在总是降低该复合结构内Love波的相速度,在一些特殊频率范围,Love波的相速度对界面缺陷非常敏感;(3)界面缺陷对压电层内的机械位移模态和电势模态有显著影响,且影响最大区域出现在界面附近.     

Effects of inhomogeneity on surface waves in anisotropic media

This paper investigates the effects of anisotropy and inhomogeneity on surface waves in elastic media. Exponential variation in properties are assumed for the elastic parameters and material density. The classical equations of motion for propagation of waves in an inhomogeneous transversely isotropic elastic solid are deduced. The equations of motion for surface waves are derived and general surface waves are investigated. This general theory is then utilized to investigate Rayleigh, Love and Stoneley waves. Results obtained in the above cases reduce to the corresponding well-known classical results when inhomogeneity and anisotropy are not present. It is seen that inhomogeneity has significant effects on dispersion characteristics. Numerical calculations are included for Love waves and some conclusions have been drawn from the above calculations.     

Aqueous Chemical Solution Deposition of Ferroelectric Thin Films

Thin films of various ferroelectric multimetal oxides such as (Bi 1 m x La x ) 4 Ti 3 O 12 (BLT), SrBi 2 Ta 2 O 9 (SBT) and PbZr 1 m x Ti x O 3 (PZT) have been prepared by an entirely aqueous chemical solution deposition (CSD) route. Two critical issues related with aqueous CSD have hereby been worked out: in spite of the high degree of hydrolysis of tetra- and pentavalent metal ions (Ti 4+ , Zr 4+ , Ta 5+ , ) we managed to prepare stable aqueous precursor solutions by chemical modification of these individual metals, avoiding phase segregation. Another problem related with aqueous CSD is the wetting of the substrate (both metallic and metal oxide) by the aqueous solution. The hydrophilicity of the substrates is optimized by a chemical treatment of the substrate surface. In this manner, the addition of wetting agents, hence possibly disturbing the gelation reactions, is avoided. In order to study the gelation, decomposition, crystalization and the morphology of the thin films, various characterization techniques ((cryo-)TEM, SEM, EDX, TGA-MS/FTIR, HT-DRIFT, HT-XRD, ) are used.     

成层介质中Love波相速度频散曲线计算的比较

根据基岩弹性半空间上水平成层覆盖土层Love波相速度频散曲线计算方法 ,编写了Fortran程序 ,计算了日本的两个实际工程场地的Love波频曲线 ,并与文献 [4 ]的计算结果进行了对比 ,验证了本文所编写的程序。     

煤层Love型槽波数值模拟及其频散特征分析

槽波地震是探查采煤工作面内部小断层或其他地质异常中的有效手段,但以往对槽波中蕴含的频散信息利用不足。采用二维高阶交错网格法模拟了煤层槽波的波场发育特征,激发震源采用横波震源,模型边界吸收采用完全匹配层法。从模拟结果可以看出:与传统槽波理论认识不同,槽波的能量不仅分布在基阶模式,高阶部分的能量也很强,这对于今后的煤矿井下槽波勘探具有一定的参考意义。     

Love波传感器的性能分析与实验

为了制作高灵敏度Love波传感器,分析了Love波在ST-石英和二氧化硅薄膜分层结构中的传播特性,并对该分层结构进行了相关的理论推导和计算.首先,从声学动力学方程出发,分析求解了该分层结构的波动方程,得到了在该分层结构的色散关系及位移表达式.基于得到的解析表达式分析了波结构,绘制了特性曲线,得到了Love波在该结构中的...