The study concerns the use of MgCl2-supported high-activity Ziegler-Natta catalysts for the polymerization of ethylene.In particular,two types of catalysts were investigated,which were N-catalyst（BRICI）and improved ...The study concerns the use of MgCl2-supported high-activity Ziegler-Natta catalysts for the polymerization of ethylene.In particular,two types of catalysts were investigated,which were N-catalyst（BRICI）and improved polyethylene catalyst.The effects of catalyst structure on kinetic behavior were examined.The distribution of active centers in these catalysts was investigated by energy dispersive analysis by X-rays（EDAX）,and morphologies of catalyst particles and polymer products were examined by scanning electron microscope（SEM）.Hydrogen response and copolymerization performance were investigated and compared with the two catalysts.The results were correlated with the kinetic behavior of the two catalysts and appropriate models for polymer particle growth were presented.The improved polyethylene catalyst showed higher activity,better hydrogen response and copolymerization performance.展开更多
We solve a generalized nonautonomous nonlinear Schrodinger equation analytically by performing the Hirota＇s bilinearization method. The precise expression of a parameter e, which provides a compatibility condition an...We solve a generalized nonautonomous nonlinear Schrodinger equation analytically by performing the Hirota＇s bilinearization method. The precise expression of a parameter e, which provides a compatibility condition and dark soliton management, is obtained. Comparing with nonautonomous bright soliton, we find that the gain parameter affects both the background and the valley of dark soliton （∈2 ≠ 1） while it has no effects on the wave central position. Moreover, the precise expressions of a nonautonomous black soliton＇s （∈2 = 1） width, background and the trajectory of its wave central, which describe the dynamic behavior of soliton＇s evolution, are investigated analytically. Finally, the stability of the dark soliton solution is demonstrated numerically. It is shown that the main characteristic of the dark solitons keeps unchanged under a slight perturbation in the compatibility condition.展开更多
文摘The study concerns the use of MgCl2-supported high-activity Ziegler-Natta catalysts for the polymerization of ethylene.In particular,two types of catalysts were investigated,which were N-catalyst（BRICI）and improved polyethylene catalyst.The effects of catalyst structure on kinetic behavior were examined.The distribution of active centers in these catalysts was investigated by energy dispersive analysis by X-rays（EDAX）,and morphologies of catalyst particles and polymer products were examined by scanning electron microscope（SEM）.Hydrogen response and copolymerization performance were investigated and compared with the two catalysts.The results were correlated with the kinetic behavior of the two catalysts and appropriate models for polymer particle growth were presented.The improved polyethylene catalyst showed higher activity,better hydrogen response and copolymerization performance.
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10975180, 11047025, and 11075126 and the Applied nonlinear Science and Technology from the Most Important Among all the Top Priority Disciplines of Zhejiang Province
文摘We solve a generalized nonautonomous nonlinear Schrodinger equation analytically by performing the Hirota＇s bilinearization method. The precise expression of a parameter e, which provides a compatibility condition and dark soliton management, is obtained. Comparing with nonautonomous bright soliton, we find that the gain parameter affects both the background and the valley of dark soliton （∈2 ≠ 1） while it has no effects on the wave central position. Moreover, the precise expressions of a nonautonomous black soliton＇s （∈2 = 1） width, background and the trajectory of its wave central, which describe the dynamic behavior of soliton＇s evolution, are investigated analytically. Finally, the stability of the dark soliton solution is demonstrated numerically. It is shown that the main characteristic of the dark solitons keeps unchanged under a slight perturbation in the compatibility condition.
