The vibration frequency of box gird is usually calculated by the elementary beam theory, but it will lead to a large error because of the existence of shear lag effect and shear deformation.
由于剪力滞效应及剪切变形的存在，箱梁的弯曲振动频率按照初等梁理论计算往往存在较大的误差。
Three general analysis methods are discussed: amplitude, time and frequency analysis, which are the most elementary methods.
幅域分析法、时域分析法以及频域分析法。
The elementary studies show that insect species can be accurately distinguished through the sound-frequency characteristics of insect activity in grain.
基于考虑能够用储粮害虫活动声频率特征鉴别害虫以达到准确用药降低其危害的目的，本文主要做了以下几方面的工作。
The elementary studies show that insect species can be accurately distinguished through the sound-frequency characteristics of insect activity in grain.
基于考虑能够用储粮害虫活动声频率特征鉴别害虫以达到准确用药降低其危害的目的，本文主要做了以下几方面的工作。
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