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By means of the adjoints method of solving the differential equations of two-point boundaryvalue problems,the equations of motion of a boundary stress-free ceramic disk vibrator polarizedin the thickness direction are solved by numerical integration.The resonance frequencies of the lowermodes of radial vibration under the influence of motion in the thickness direction and the particledisplacement distribution patterns are obtained for disks whose thickness-diameter ratios are less than0.45.Correction curves for thickness effect on fundamental frequencies are given.Curves showing.the effect of Poisson ratio on the relation between the second harmonic-fundamental ratio and thethickness-diameter ratio are also given. In the numerical calculations,piezoelectric ptoperties of the ceramic disks are fully taken intoconsideration and no restrictions are set for the dimensions of the disks.Experimental results agreewell with those obtained by calculation. 相似文献
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超声是近代声学中发展较快而应用较广的一个分支.近年来获得高频超声的技术的迅速发展,更扩大了它的应用范围.在一些基本科学问题的研究中,超声已成为有力的工具之一.本文简略地描述了超声的产生及测量方法,并以在化学中及固体物理中的应用为例,阐明它在一些科学研究中的应用. 相似文献
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近十几年来,已经出版的有关建筑声学方面的书籍为数不少。但至今缺少一本以建筑师为主要对象、建筑工程设计程序为主导,分述各类建筑声学设计的专著。项端祈同志编著的《实用建筑声学》一书的出版(中国建筑工业出版社,1992,12,115万字)填补了这一空白。该书由著名科学家马大猷教授执笔作序,并给予很高的评价。这是我国第一部由建筑师编写、全面论述各类建筑声学设计的专著,是一本集国内外声学设计经验之大成的好书,值得推荐。 相似文献
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