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Development of Directional Point-Focus-Beam Acoustic Microscope System

定向点聚焦束声显微镜系统的研制

基本信息

批准号：
02555083
负责人：
CHUBACHI Noriyoshi
金额：
$ 10.5万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1992
项目状态：
已结题

项目摘要

A practical system of directional point-focus-beam(PFB) acoustic microscope with two functions of imaging and quantitative measurements has been developed as a new research tool to characterize anisotropic materials on a microscopic scale in the VHF and UHF ranges. Directional PFB acoustic probes in the frequency range of 200-400 MHz have been developed by introducing directionality into a PFB acoustic probe, limiting excitation of leaky surface acoustic waves(LSAWs) within a narrow angle with a rectangular transducer instead of a circular transducer.It has been revealed that it is essential to take into consideration the effect of beam steering of LSAWs due to the elastic anisotropy on the transducer output of the acoustic probe in order to realize a directional PFB acoustic microscope, and to limit the region of defocusing distance near the focal point for the V(z) curve analysis.It is necessary to chose arbitrarily an imaging area and an LSAW propagation direction, for characterizing the elastic properties of anisotropic materials on a microscopic area in imaging and quantitative measurements. The mechanical and electrical systems have been developed, and the experimental procedures in measurements have been established.The system has been demonstrated for investigation of a polycrystalline sample of Mn-Zn ferrite with an average grain size of 100mum. Directional acoustic images were obtained at 225 and 375 MHz for several different propagation directions of LSAWs. Anisotropy measurements of LSAW velocity in some grains of the sample have been performed through V(z) curve analysis. Anisotropic elastic properties of each grain have been characterized both in imaging and quantitative measurements.

一种实用的定向点聚焦光束（PFB）声学显微镜系统，具有成像和定量测量两种功能，作为一种新的研究工具，可以在甚高频和超高频范围内的微观尺度上表征各向异性材料。通过在 PFB 声学探头中引入方向性，用矩形换能器而不是圆形换能器将泄漏表面声波 (LSAW) 的激励限制在窄角度内，开发了频率范围为 200-400 MHz 的定向 PFB 声学探头。研究表明，必须考虑由于弹性体而导致 LSAW 波束转向的影响。为了实现定向PFB声学显微镜，并限制V(z)曲线分析焦点附近的离焦距离区域，需要对声探头换能器输出的各向异性进行研究。为了在成像和定量测量中表征微观区域各向异性材料的弹性特性，需要任意选择成像区域和LSAW传播方向。开发了机械和电气系统，并建立了测量实验程序。该系统已被证明可用于研究平均晶粒尺寸为100μm的锰锌铁氧体多晶样品。在 225 和 375 MHz 下获得了 LSAW 几个不同传播方向的定向声学图像。通过 V(z) 曲线分析对样品某些颗粒中的 LSAW 速度进行了各向异性测量。每种颗粒的各向异性弹性特性已通过成像和定量测量进行了表征。