In this paper, we discuss the counting prob lem of an order n-group of set (A 1,A 2,…,A n) which satisfies ∪ni=1A i=｛a 1,a 2,…,a m｝ and one of the following: (1) ∩ni=1A i=Φ; (2) ∩ni=1A i=｛b 1,b 2,…,b k｝;(3)...In this paper, we discuss the counting prob lem of an order n-group of set (A 1,A 2,…,A n) which satisfies ∪ni=1A i=｛a 1,a 2,…,a m｝ and one of the following: (1) ∩ni=1A i=Φ; (2) ∩ni=1A i=｛b 1,b 2,…,b k｝;(3) ∩ni=1A 1｛b 1,b 2,…,b k｝; (4) A i≠Φ (i=1,2,…,k). We solve these problems by element analytical meth od.展开更多
A synthetic method for a new unsymmetrical Schiff base and its Ln(Ⅲ)complexes including multi > C = N — groups is reported. The complexes are characterized byelemental analysis, IR spectra, ~1H and ^(13)C NMR, es...A synthetic method for a new unsymmetrical Schiff base and its Ln(Ⅲ)complexes including multi > C = N — groups is reported. The complexes are characterized byelemental analysis, IR spectra, ~1H and ^(13)C NMR, especially 2D-COSY ~1H, ~1H NMR spectra. Thegeneral formula of the obtained complexes is [Ln_3(TBLY)(NO_3)_3] · nH_2O (Ln = La, n = 3; Ln = Nd,n=5; Ln = Gd, Dy, Yb, Y, n = 7), where TBLY = tetraglycol aldehyde-2,4-dihydroxy benzaldehydebis-lysine Schiff base. In addition, the evidence for existence of > C = CH — NH — group issupported by the AM1 method. The complexes obtained may be used as a catalyst. Conversion rate of80% with the viscosity-average molecular weight 220000 for the polymerization of methyl methacrylate(MMA) without addition of any cocatalyst has been obtained.展开更多
文摘In this paper, we discuss the counting prob lem of an order n-group of set (A 1,A 2,…,A n) which satisfies ∪ni=1A i=｛a 1,a 2,…,a m｝ and one of the following: (1) ∩ni=1A i=Φ; (2) ∩ni=1A i=｛b 1,b 2,…,b k｝;(3) ∩ni=1A 1｛b 1,b 2,…,b k｝; (4) A i≠Φ (i=1,2,…,k). We solve these problems by element analytical meth od.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 29671026) Natural Science Foundation of Zhejiang Province (Grant No. 296062) and the Laboratory of MRAMP (Grant No. 971502). References
文摘A synthetic method for a new unsymmetrical Schiff base and its Ln(Ⅲ)complexes including multi > C = N — groups is reported. The complexes are characterized byelemental analysis, IR spectra, ~1H and ^(13)C NMR, especially 2D-COSY ~1H, ~1H NMR spectra. Thegeneral formula of the obtained complexes is [Ln_3(TBLY)(NO_3)_3] · nH_2O (Ln = La, n = 3; Ln = Nd,n=5; Ln = Gd, Dy, Yb, Y, n = 7), where TBLY = tetraglycol aldehyde-2,4-dihydroxy benzaldehydebis-lysine Schiff base. In addition, the evidence for existence of > C = CH — NH — group issupported by the AM1 method. The complexes obtained may be used as a catalyst. Conversion rate of80% with the viscosity-average molecular weight 220000 for the polymerization of methyl methacrylate(MMA) without addition of any cocatalyst has been obtained.
