I was standing by the back corner of the truck, struggling to fight back the sudden wave of emotion the snow chains had brought on, when I heardan odd sound.
我站在卡车后面的一个角落里，努力的和突然来自这防滑链带来的情感斗争着，直到我听到了一个奇怪的声音。
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Methods Use a standingwave tube to measure the sound absorption coefficient of many kinds of grain.
采用驻波管法测量了多种粮食的吸声系数。
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This article research content and research results mainly includes following parts: Phononic crystals new sound insulating material standingwave tube test modelling.