摘要
回顾了实验室中超声波测量Q值的四种常用方法 :上升时间法、回声法、频谱振比法和波形反演法。在综合了回声法和频谱振幅比法优点的基础上 ,提出等效声阻抗法。该方法借助于参考样品 ,利用其一、二次波的振幅谱 ,计算换能器和耦合层的等效声阻抗 ,进而由待测样品的一、二次波振幅谱计算其衰减 ,求得其与频率有关的Q值。对振幅谱进行了扩散校正 ,并利用该方法测量了有机玻璃和饱水岩石样品的Q值。对该方法的可靠性也进行了讨论。
The four common ultrasonic methods for measuring Q value in the laboratory, rise time, pulse echo, spectral ration and waveform inversion techniques are reviewed. Based on synthesizing advantages of the pulse echo and spectral ration techniques, a new method, the equivalent acoustic impedance technique is proposed. Using spectra of the first and second waves in reference, the equivalent acoustic impedance of the transducer and couplet is calculated; attenuation of the sample is estimated by analyzing the spectra of the first and second waves in it, and the Q value spectrum for the sample is obtained from the attenuation finally. Diffraction for the spectra is corrected and the Q values of organic glass and water-saturated rock samples are measured. The reliability of this method is also discussed.
出处
《地震研究》
CSCD
北大核心
2000年第3期324-328,共5页
Journal of Seismological Research
基金
国家自然科学基金!(498740 43)
地震科学联合基金!(1980 90 )资助项目
关键词
Q值
超声波
等效声阻抗
岩石
Q value, ultrasonic wave, equivalent acoustic impedance
