This paper presents a character table of S_4 wr S_2 wreath product group.Using this character table,~1H or ^(13)C NMR spectra analysis of molecula with S_4[S_2]symmetry,especially simplification of the secular determi...This paper presents a character table of S_4 wr S_2 wreath product group.Using this character table,~1H or ^(13)C NMR spectra analysis of molecula with S_4[S_2]symmetry,especially simplification of the secular determinant equation will be easy to carry out. Molecules with S_4[S_2]symmetry,are exemplified by octaphenylcyclo- tetrasiloxane and 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine chromium (Ⅲ)chloride.展开更多
Investigation by using LAS 3000 surface analysis system showed that the oxide of Fe, Cr,Al formed during oxidation were Cr_2O_3,Fe_2O_3 and Al_2O_3,but only small amount of nickel oxide was found. The composition of o...Investigation by using LAS 3000 surface analysis system showed that the oxide of Fe, Cr,Al formed during oxidation were Cr_2O_3,Fe_2O_3 and Al_2O_3,but only small amount of nickel oxide was found. The composition of oxide layers for different oxidation durations varied in a similar way. In all cases,there exists an oxygen concentration peak in the composition profile of oxide layer. There is a transitional zone between oxide layer and alloy film.The thickness of oxide layer increases logarithmically with the time of oxida- tion.The ion plated Ni-Cr alloy film has very dense oxide layer and good oxidation resistance.展开更多
文摘This paper presents a character table of S_4 wr S_2 wreath product group.Using this character table,~1H or ^(13)C NMR spectra analysis of molecula with S_4[S_2]symmetry,especially simplification of the secular determinant equation will be easy to carry out. Molecules with S_4[S_2]symmetry,are exemplified by octaphenylcyclo- tetrasiloxane and 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine chromium (Ⅲ)chloride.
文摘Investigation by using LAS 3000 surface analysis system showed that the oxide of Fe, Cr,Al formed during oxidation were Cr_2O_3,Fe_2O_3 and Al_2O_3,but only small amount of nickel oxide was found. The composition of oxide layers for different oxidation durations varied in a similar way. In all cases,there exists an oxygen concentration peak in the composition profile of oxide layer. There is a transitional zone between oxide layer and alloy film.The thickness of oxide layer increases logarithmically with the time of oxida- tion.The ion plated Ni-Cr alloy film has very dense oxide layer and good oxidation resistance.
