The effect of rare earths (Sm, Pr, Ce, Nd and La) on the hydrogenation properties ofp-chloronitrobenzene (CNB) over Pt/CNTs catalyst was studied in ethanol at 303 K and normal pressure. The results exhibited that ...The effect of rare earths (Sm, Pr, Ce, Nd and La) on the hydrogenation properties ofp-chloronitrobenzene (CNB) over Pt/CNTs catalyst was studied in ethanol at 303 K and normal pressure. The results exhibited that the hydrogenation of p-CNB could be carried out over PtMOx/CNTs catalysts. Both catalytic activities and yields ofp-chloroaniline (CAN) were all improved. PtCeOx/ CNTs catalyst exhibited the best catalytic activity (TOF was 0.47 s^-1) and the highest yield of p-CAN (97.5 mol%). PtCeOx/CNTs (1.0 wt%) catalyst exhibited good stability on the hydrogenation of p-CNB.展开更多
Let X* be a free monoid over an alphabet X and W be a finite language over X. Let S(W) be the Rees quotient X*/I(W), where I(W) is the ideal of X* consisting of all elements of X* that are not subwords of W....Let X* be a free monoid over an alphabet X and W be a finite language over X. Let S(W) be the Rees quotient X*/I(W), where I(W) is the ideal of X* consisting of all elements of X* that are not subwords of W. Then S(W) is a finite monoid with zero and is called the discrete syntactic monoid of W. W is called finitely based if the monoid S(W) is finitely based. In this paper, we give some sufficient conditions for a monoid to be non-finitely based. Using these conditions and other results, we describe all finitely based 2-limited words over a three-element alphabet. Furthermore, an explicit algorithm is given to decide that whether or not a 2-limited word in which there are exactly two non-linear letters is finitely based.展开更多
文摘The effect of rare earths (Sm, Pr, Ce, Nd and La) on the hydrogenation properties ofp-chloronitrobenzene (CNB) over Pt/CNTs catalyst was studied in ethanol at 303 K and normal pressure. The results exhibited that the hydrogenation of p-CNB could be carried out over PtMOx/CNTs catalysts. Both catalytic activities and yields ofp-chloroaniline (CAN) were all improved. PtCeOx/ CNTs catalyst exhibited the best catalytic activity (TOF was 0.47 s^-1) and the highest yield of p-CAN (97.5 mol%). PtCeOx/CNTs (1.0 wt%) catalyst exhibited good stability on the hydrogenation of p-CNB.
基金Supported by National Natural Science Foundation of China (Grant No. 10971086)Mathematical Tianyuan Foundation of China (Grant No. 11126186)+1 种基金Natural Science Foundation of Gansu Province (Grant No.1107RJZA218)Fundamental Research Funds for Central Universities (Grant No. lzujbky-2012-12)
文摘Let X* be a free monoid over an alphabet X and W be a finite language over X. Let S(W) be the Rees quotient X*/I(W), where I(W) is the ideal of X* consisting of all elements of X* that are not subwords of W. Then S(W) is a finite monoid with zero and is called the discrete syntactic monoid of W. W is called finitely based if the monoid S(W) is finitely based. In this paper, we give some sufficient conditions for a monoid to be non-finitely based. Using these conditions and other results, we describe all finitely based 2-limited words over a three-element alphabet. Furthermore, an explicit algorithm is given to decide that whether or not a 2-limited word in which there are exactly two non-linear letters is finitely based.