图3. 不同硅铝比Na-SSZ-39分子筛的(a~c)一维27Al MAS NMR谱和(d~f)二维27Al MQ MAS NMR谱
Fig.3. (a~c) 1D 27Al MAS NMR and (d~f) 2D 27Al MQ MAS NMR spectra of Na-SSZ-39 zeolites with various Si/Al ratios