The interaction properties of periodic waves are found to be inelastic.

研究了这些周期波之间的相互作用，发现其相互作用是非弹性的。

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The periodic mean superposition method can predict the result through decomposing the hydrological time series into several periodic waves, extrapolating the periodic waves, and linear superposition.

周期均值叠加法将随时间变化的水文要素序列分离成若干个周期波，然后将周期波进行外延，再进行线性叠加，从而获得预报结果。

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Conditions for the existence of solutions to periodic and isolated waves of limited amplitude are directly obtained based on qualitative geometric theory for ordinary differential equations.

利用微分方程解的几何定性理论，直接得到该方程存在有限振幅的周期波与孤立波解的存在条件。

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So, for example, we have this average level, and then it can go high where we have the peak, or it can go very low. We can also discuss sound waves, so again it's just the periodic variation of some property -- in this case we're talking about density, so we have high density areas and low density areas.

例如这是平均位置，在峰的位置水位高，在谷水位低，我们也可以,讨论声波它也是某种,量的周期变化，在这里我们,讨论的是密度,我们有高密度区和低密度区。

麻省理工公开课 - 化学原理课程节选