The valence states of iron in iron catalysts,hydrogen reduced catalysts,and catalytically grown carbon nanotubes are determined by Mössbauer spectra,respectively.The results show that the iron exists as Fe,FeO,an...The valence states of iron in iron catalysts,hydrogen reduced catalysts,and catalytically grown carbon nanotubes are determined by Mössbauer spectra,respectively.The results show that the iron exists as Fe,FeO,andα-Fe_(2)O_(3) in hydrogen reduced catalysts,whereas it exists as Fe-C alloy,FeO,and α-Fe_(2)O_(3) in the catalysts encapsulated in carbon nanotube.It is postulated that Fe in hydrogen reduced catalysts plays the main role in the formation of catalytically grown carbon nanotube.展开更多
Hydrogenated nanocrystalline silicon nitrogen(nc-SiN_(x):H)films were prepared by rf glow discharge of gas mixture of silane(SiH_(4))and nitrogen(N_(2))diluted heavily by hydrogen(H_(2)).The effect of the gas volume r...Hydrogenated nanocrystalline silicon nitrogen(nc-SiN_(x):H)films were prepared by rf glow discharge of gas mixture of silane(SiH_(4))and nitrogen(N_(2))diluted heavily by hydrogen(H_(2)).The effect of the gas volume ratios X_(g) of(SiU_(4)+N_(2))/H_(2) and X_(N)of N_(2)/SiH_(4) on the crystallization and composition of films is described.The growth process and crystallization mechanism of nc-SiN_(x):H films are discussed in detail.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.59642006。
文摘The valence states of iron in iron catalysts,hydrogen reduced catalysts,and catalytically grown carbon nanotubes are determined by Mössbauer spectra,respectively.The results show that the iron exists as Fe,FeO,andα-Fe_(2)O_(3) in hydrogen reduced catalysts,whereas it exists as Fe-C alloy,FeO,and α-Fe_(2)O_(3) in the catalysts encapsulated in carbon nanotube.It is postulated that Fe in hydrogen reduced catalysts plays the main role in the formation of catalytically grown carbon nanotube.
基金Supported in part by the National Postdoctoral Foundation of China.
文摘Hydrogenated nanocrystalline silicon nitrogen(nc-SiN_(x):H)films were prepared by rf glow discharge of gas mixture of silane(SiH_(4))and nitrogen(N_(2))diluted heavily by hydrogen(H_(2)).The effect of the gas volume ratios X_(g) of(SiU_(4)+N_(2))/H_(2) and X_(N)of N_(2)/SiH_(4) on the crystallization and composition of films is described.The growth process and crystallization mechanism of nc-SiN_(x):H films are discussed in detail.
