The novel I Love Dick,written by Chris Kraus,discusses the“least described”social problem.The novel starts with describing Chris’s love affair.Her love affair is narrated with her illustrations of some social probl...The novel I Love Dick,written by Chris Kraus,discusses the“least described”social problem.The novel starts with describing Chris’s love affair.Her love affair is narrated with her illustrations of some social problems that are shrunk into personal problems.This article aims to examine how she uses the schizophrenic utterances to illustrate the failure of her love affair differently.展开更多
Two new unbridged zirconocenes, bis(2.4,7-trimethyl indenyl)zirconium dichloride (Met-I) and bis(2-methyl-4,7-diethyl indenyl)zirconium dichloride (Met-II) were prepared in order to investigate the steric effects of s...Two new unbridged zirconocenes, bis(2.4,7-trimethyl indenyl)zirconium dichloride (Met-I) and bis(2-methyl-4,7-diethyl indenyl)zirconium dichloride (Met-II) were prepared in order to investigate the steric effects of substituents on the nature of the catalysts for the: polymerization of propylene. A mixture of methyl aluminoxane (MAO) and triisobutylaluminum [Al(iBu)(3)] was used as cocatalyst to activate these catalysts. The decrease in steric bulkiness of substituents at 4 and 7 positions of the indenyl ring resulted in an increase of both activity and molecular weight as well as the isotacticity.展开更多
Two unbridged metallocene catalysts, bis(2,4,7-trimethylindenyl)zirconium dichloride (met-I) and bis(2,4,6-trimethylindenyl)zirconium dichloride (met-II), which are different in the position of substituents on the six...Two unbridged metallocene catalysts, bis(2,4,7-trimethylindenyl)zirconium dichloride (met-I) and bis(2,4,6-trimethylindenyl)zirconium dichloride (met-II), which are different in the position of substituents on the six-membered ring of the indenyl ligands were synthesized. The effect of substituents in the two metallocenes on the propylene polymerization was studied in the presence of methylaluminoxane (MAO) and triisobutylaluminium (TIBA). From the analysis of microstructure determined by C-13-NMR, it was demonstrated that the polymers produced by met-II have higher [mmmm] isotactic sequences than that of met-I. Using a mechanism based on model statistical analysis, it was found that chain-end model was dominant for met-I. However, met-II obeys the concurrent two-sites model during polymerization, which can be attributed to the existence of 'racemic-like' conformer in its system.展开更多
文摘The novel I Love Dick,written by Chris Kraus,discusses the“least described”social problem.The novel starts with describing Chris’s love affair.Her love affair is narrated with her illustrations of some social problems that are shrunk into personal problems.This article aims to examine how she uses the schizophrenic utterances to illustrate the failure of her love affair differently.
基金This project has been supported by the National Natural Science Foundation of China and the Petrochemical Incorporation of China (grant number 29734144).
文摘Two new unbridged zirconocenes, bis(2.4,7-trimethyl indenyl)zirconium dichloride (Met-I) and bis(2-methyl-4,7-diethyl indenyl)zirconium dichloride (Met-II) were prepared in order to investigate the steric effects of substituents on the nature of the catalysts for the: polymerization of propylene. A mixture of methyl aluminoxane (MAO) and triisobutylaluminum [Al(iBu)(3)] was used as cocatalyst to activate these catalysts. The decrease in steric bulkiness of substituents at 4 and 7 positions of the indenyl ring resulted in an increase of both activity and molecular weight as well as the isotacticity.
基金This project was supported by the National Natural Science Foundation of China and the Petrochemical Incorporation of China (Grant number: 29734144).
文摘Two unbridged metallocene catalysts, bis(2,4,7-trimethylindenyl)zirconium dichloride (met-I) and bis(2,4,6-trimethylindenyl)zirconium dichloride (met-II), which are different in the position of substituents on the six-membered ring of the indenyl ligands were synthesized. The effect of substituents in the two metallocenes on the propylene polymerization was studied in the presence of methylaluminoxane (MAO) and triisobutylaluminium (TIBA). From the analysis of microstructure determined by C-13-NMR, it was demonstrated that the polymers produced by met-II have higher [mmmm] isotactic sequences than that of met-I. Using a mechanism based on model statistical analysis, it was found that chain-end model was dominant for met-I. However, met-II obeys the concurrent two-sites model during polymerization, which can be attributed to the existence of 'racemic-like' conformer in its system.
