一维固-固结构圆柱声子晶体中弹性波的传输特性

利用一维固-固结构圆柱声子晶体中弹性波横向受限的条件,推导出弹性波在其中各个模式满足的关系式,利用它研究了弹性波各模式的特性.并利用转移矩阵研究了弹性波的传输特性随模式量子数和圆柱半径的变化规律.得出了一些一维固-固结构圆柱声子晶体的新特征,即弹性波的传输特性由模式量子数和圆柱半径决定. 关键词： 圆柱声子晶体 弹性波 受限 模式     

锐钛相介孔SO42-/TiO2的声化学制备及结构和催化酯化性能

不使用有机模板剂,采用超声化学法一步水解制得吸附硫酸根的介孔偏钛酸,500℃焙烧得到介孔SO2-4/TiO2固体超强酸.用XRD、TFEM、FTIR、低温氮吸附-脱附等手段对催化剂结构进行了表征.结果表明,硫酸根在焙烧过程中与前驱体介孔偏钛酸孔壁上自由羟基的键合起到了孔结构导向及支撑作用,500℃焙烧后样品具有161 m2·g-1的比表面积及4.1 nm的平均孔径,酸强度H0介于-14.52与-16.02之间,硫含量为2.8%,晶型全部为锐钛矿相,介孔SO2-4/TiO2具有较大比表面、强酸特性和稳定性.催化合成富马酸二甲酯的最佳条件为:n(甲醇):n(富马酸)=6:1,催化剂用量为1.0%(反应物总质量),带水剂苯用量为10 mL,反应时间为3 h,催化剂重复使用7次,酯化率大于90%.     

利用散射波远场模第P个傅立叶系数重建声波阻尼系数

阐述了利用声波散射远场模Fourier展开的第P个傅立叶系数（声散射远场模的不完全信息）,重建声阻抗系数的一种非线性最优化方法．并给出了该方法收敛性的证明,其数值例子说明这种方法的有效性和可行性．     

Photoluminescence study of the annihilation process of donor-bound excitons in ZnO： observation of quantum mechanical interference

We report a photoluminescence observation of the coupling of donor-bound excitons and longitudinal optical phonons in high-quality ZnO crystals at 5 K. The first-order phonon Stockes line of donor-bound excitons exhibits a distinct asymmetric line shape with a clear dip at its higher energy side, suggesting that quantum mechanical interference occurs during the annihilation of donor-bound excitons. The donor binding energy is determined to be 49.3 meV from spectral featural.     

分形介质声子导热的频域问题

本文论证了分形介质中声子导热的必要条件，给出了分形介质定容比热的频域。结果表明，同一材料的分形介质定容比热恒小于均匀介质的定容比热。     

一维C_(36)聚合物的C_(36)分子间的电-声相互作用

在用半经验自洽场晶体轨道方法计算能带结构的基础上，并在平均场近似和形变势理论框架下，研究了四种一维线性 C36聚合物模型的 C36分子间电 声耦合常数及其对超导相变和金属 绝缘体相变的影响 .计算结果表明，一维线性 C36聚合物的 C36分子间电 声耦合常数极小，对超导相变和金属 绝缘体相变的影响可以完全忽略 .     

一维固-液掺杂声子晶体缺陷模的机理研究

建立了一维固-液掺杂声子晶体的谐振腔模型,利用谐振腔的共振条件推导出了缺陷模频率满足的解析公式,从理论上解释了产生一维固-液掺杂声子晶体缺陷模的物理机理.利用频率的解析公式研究了缺陷模的频率随入射角、杂质厚度、杂质波速的变化规律.结果表明:缺陷模的频率随入射角和杂质波速的增加而增加,缺陷模的频率随杂质厚度的增加而减少,圆满地解释了一维固-液掺杂声子晶体缺陷模的变化规律.在此基础上并与转移矩阵法的计算结果进行了比较,其结果吻合.     

Surface Acoustic Wave Characterization of Equivalent Young's Moduli for Patterned Films北大核心CSCD

Based on the equivalent elasticity theory for layered materials, the micro-mechanics equivalent models for single and dual damascene structures were established. The equivalent elastic constant of the patterned structure was introduced, to establish the propagation model for the surface acoustic waves propagating in the layered structure of the patterned film/ substrate, and the theoretical dispersion curves of the surface acoustic waves were calculated with Green’s function and the matrix method. The finite element method was used to calculate 24 numerical examples of damascene structures with different volume ratios, and the results were compared with those of the strain energy method. The results show that, the average relative errors of the equivalent Young’s moduli of the 300 nm-thick dual damascene film and the 100 nm-thick single damascene film are 2.06% and 2.27%, respectively. The research verifies the correctness of the equivalent patterned structure model and the feasibility of the surface acoustic wave method to characterize the mechanical properties of patterned films, and provides a reference for the development of suitable chemico-mechanical polishing technologies for patterned films under low pressure. © 2023 Editorial Office of Applied Mathematics and Mechanics. All rights reserved.