These researches provide us a basis for forecasting the pests in grain in earlier stage , accurately utilizing pesticides , improving the efficiency of prevention and reducing the loss of stored grain . the sound absorption properties of various types and thickness of grain are measured by means of the standing wave tube technique . the following conclusions can be drawn : for the same thickness the larger grains has a smaller sound absorption coefficient than the smaller grains 为了有效地研究储粮害虫所产生声信号在各种粮食中的传播特性，本文采用驻波管法，对十一种不同种类粮食在不同堆积厚度情况下的吸声性能进行了实验研究，粮食吸声特性与其颗粒的大小、形状、排列方式及粮食堆积厚度等有关，存在一定的规律，得出如下结论：同一厚度下，颗粒大的粮食较颗粒小的吸声性能差，颗粒由大到小，吸声系数峰值频率向低频方向移动；球形颗粒粮食较长形颗粒吸声性能差。
As an important component in laminated composites , the foamed polymer material ( polyurethane foam , puf ) is also studied in this paper . the viscoelastic property ' s influence on absorption property is studied by fem , and the relationship between the macroscopical physical properties and the absorption property is researched by experiment 另外对作为层合复合降噪材料重要组份之一的高聚物发泡材料( puf )的吸声性能进行了探讨，通过有限元方法模拟其粘弹性能对吸声性能的影响，并实验研究了其宏观物理表征与吸声性能的关系。
