Thirdly , considering when acoustic wave with a certain frequency or angle is incident upon plates , it will greatly cause the radiation power " translating . this paper details the causes of coincident effect and gets the calculating formula . the conclusion is resulted that thick plate and uniaxial anisotropies can lower critical frequency 针对声波入射板面时在某一特定频率或特定入射角度时会使声辐射能力大大增加并产生声能的大量透射这一现象，详细讨论了产生吻合效应的条件；并针对工程实际中所应用到的各种尺寸、材质的板分别推导了其吻合频率和临界频率的计算公式，得出了厚板和材料的各向异性均会使结构的临界频率下降的结论。
The progress of laser ultrasonics has been discussed especially for the laser - generated surface acoustic wave . the transform process of energy from light to ultrasonic has been analyzed . the generation mechanism of laser - generated surface acoustic wave has been discussed in detail excluding thermo - elastic mode and illumination mode 介绍了激光超声领域的研究进展，分析了光致超声过程中，能量从光能到声能的转换，归纳了用激光激发声表面波的机理，讨论了两种主要的模型：热弹模型和融蚀模型。
