even-order harmonic造句

• Our study indicates that intensity of odd - order harmonic generation decreases , even - order harmonic generation appears and the hhg spectrum exhibits a double - plateau structure in the presence of a static electric field
  研究表明，静电场加入后，奇次谐波的强度有所降低，并且谐波谱中出现偶次谐波和双平台结构。