【摘要】 使用改装的双排换能器声速测量仪，根据时差法原理，利用示波器上的光标键测时间，不但能定性观察到声速在颗粒物质中相对于在空气中变小的现象，而且通过同步移动接收端换能器，还能测量出颗粒物质中与空气中的声速大小，定量比较得出颗粒物质中的声速比空气中的小．更多还原

【Abstract】 The modified double-row transducer sound velocity measuring instrument could use the cursor keys on the oscilloscope to measure the time based on the principle of the time difference method.The phenomenon that the velocity of sound in the particulate matter becomes smaller than that in the air could be qualitatively observed by this device,and the velocity of sound in the particulate matter and in the air could be measured by synchronous moving receiver transducer.The sound velocity in the particulate matter less than that in the air was obtained by quantitative comparison.更多还原