New transition metal sandwich compounds, [(η 5-C 5H 5)M(MeSiB 10H 10)] -(M=Co, Rh and Ir) have been investigated by using DFT/B3LYP method with relativistic pseudopotentials to study the optimized geometry and the el...
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New transition metal sandwich compounds, [(η 5-C 5H 5)M(MeSiB 10H 10)] -(M=Co, Rh and Ir) have been investigated by using DFT/B3LYP method with relativistic pseudopotentials to study the optimized geometry and the electronic *** results obtained are in good agreement with the experimental *** is concluded that silaborane cage has stronger coordination abilities and the metal-Si bond length is very *** electronic structure characters indicate that these sandwich cpmplexes satisfy the 18-electron rule, although they are thermally stable, and they may be photochemically active.
SARS is a positive-stranded virus featuring the largest viral RNA genomes today. The viral main proteinase(Hydrolase), controlling the activities of SARS virus replication , is an attractive target for therapy. We det...
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SARS is a positive-stranded virus featuring the largest viral RNA genomes today. The viral main proteinase(Hydrolase), controlling the activities of SARS virus replication , is an attractive target for therapy. We determined crystal structure for transmissible gastroenteritis virus(TGEV) hydrolase, and constructed a homology model for SARS coronavirus proteinase on Silicon Graphics station by Insight Ⅱ molecule simulation software. The structure may reveal remarkable degree of conservation of the substrate binding sites. We design an imaginable peptide precursor for inhibitor, and the base shape of pocket and property of the residues may be used as a basis for designing anti-SARS drugs.
This work deals with the dependence of the z-average mean-square radius of gyration ( z) on the degree of branching(DB) for highly branched copolymers made from the one-pot cocondensation of AB 2 and AB monomers. A ne...
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This work deals with the dependence of the z-average mean-square radius of gyration ( z) on the degree of branching(DB) for highly branched copolymers made from the one-pot cocondensation of AB 2 and AB monomers. A new expression of the degree of branching has been derived. The DB monotonously increases with increasing A group conversion and the fraction of AB 2 monomers. The value of DB calculated in accordance with our formula is lower than that given by Frey and coworkers. Howerver, when the reaction approaches completion, our expression of the degree of branching degenerates into the equation reported by Frey. Furthermore, the z-average mean-square of gyration of the resulting copolymer in the Θ state has been derived on the basis of the classical work developed by Stockmayer, Gordon, Li and Ba. The relationship between DB and z is illustrated by numerical results. The z-average mean-square radius of gyration of the copolymer with a certain weight-average molecular weight monotonously decreases with increasing the degree of branching.
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