In order to expand the application of poly（p-dioxanone） or PPDO in biomedical area,a series of novel copolymers were synthesized successfully by one-step,melted copolymerization of p-dioxanone（PDO） and L-phenylala...In order to expand the application of poly（p-dioxanone） or PPDO in biomedical area,a series of novel copolymers were synthesized successfully by one-step,melted copolymerization of p-dioxanone（PDO） and L-phenylalanine N-carboxyanhydride（L-Phe-NCA） monomers.With the in-feed molar ratio of L-PheNCA /PDO equal to 1/20,the conversions of the two kinds of monomers were calculated from 1H NMR. The average molecular weight and polydispersity of the copolymer increase with the increasing reaction time and catalyst concentration.However,the conversions of the two kinds of monomers did not change with the reaction conditions.A three-step mechanism is presented and proved by high resolution 1H NMR and IR spectrums.展开更多
Using the improved L-P method, the authors seek to salve a class of problems of square strongly nonlinear free oscillations and of strongly nonlinear nonoscillations. Their first-order approximate solutions which has ...Using the improved L-P method, the authors seek to salve a class of problems of square strongly nonlinear free oscillations and of strongly nonlinear nonoscillations. Their first-order approximate solutions which has high accuracy are obtained. The method of this paper is different from the known L-P methods.展开更多
基金supported financially by the "Western Light" joint researcher program of Chinese Academy of Science
文摘In order to expand the application of poly（p-dioxanone） or PPDO in biomedical area,a series of novel copolymers were synthesized successfully by one-step,melted copolymerization of p-dioxanone（PDO） and L-phenylalanine N-carboxyanhydride（L-Phe-NCA） monomers.With the in-feed molar ratio of L-PheNCA /PDO equal to 1/20,the conversions of the two kinds of monomers were calculated from 1H NMR. The average molecular weight and polydispersity of the copolymer increase with the increasing reaction time and catalyst concentration.However,the conversions of the two kinds of monomers did not change with the reaction conditions.A three-step mechanism is presented and proved by high resolution 1H NMR and IR spectrums.
文摘Using the improved L-P method, the authors seek to salve a class of problems of square strongly nonlinear free oscillations and of strongly nonlinear nonoscillations. Their first-order approximate solutions which has high accuracy are obtained. The method of this paper is different from the known L-P methods.
