905 resultados para ~(133)Cs NMR


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本工作以EV共聚物为研究对象,明确地提出了共聚物的序列结构与其~(13)C NMR谱,包括符号表示在内的一致性问题。通过对EVAc共聚物~(13)C NMR谱的分析认为,共聚物的序列结构与其~(13)C NMR谱之间存在着某种内在的联系。我们从EV共聚物序列结构的符号表示和Bovey关系出发,阐述了它们之间的一致性,即一一对应关系,并发现了EV共聚物~(13)C NMR谱的两种类型,提出了利用取代基参数进行EV共聚物~(13)C NMR谱分类的判别标准及其衍生出的两种判别方法,阐述了关于EV共聚物~(13)C NMR谱峰分布的预见性。

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聚苯硫醚(PPS)是特种工程塑料中应用最广、价格最低的品种。但由于其耐冲击性差,限制了其做为结构材料的应用。本论文通过多种研究方法,研究了PPS抗冲击性差的根本原因和改善途径,从改变其聚集态结构入手,使韧性得到了很大改善,为高抗冲PPS的研制提供和积累了丰富了可靠的数据,其创新性成果体现在:提出了含刚性非晶相、可动(类液)非晶相和晶相的PPS三相模型并计算了各相的相对含量、测定了各相的密度;发现了PPS的冲击强度与其结晶度呈近似线性的关系。是十分有意义的基础性工作。用核壳乳液聚合物做为PC的增韧剂,有效地控制了共混物的形态结构、计算出了界面层厚度与界面张力,为制备具有综合性能的改性PC材料奠定了理论和实践基础。

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The geometrical parameters and electronic structures of C60, (A partial derivative C60) (A = Li, Na, K, Rb, Cs) and (H partial derivative C60) (H = F, Cl, Br, I) have been calculated by the EHMO/ASED (atom superposition and electron delocalization) method. When putting a central atom into the C60 cage, the frontier and subfrontier orbitals of (A partial derivative C60) (A = Li, Na, K, Rb, Cs) and (H partial derivative C60) (H = F, Cl) relative to those of C60 undergo little change and thus, from the viewpoint of charge transfer, A (A = Li, Na, K, Rb, Cs) and H (H = F, Cl) are simply electron donors and acceptors for the C60 cage resPeCtively. Br is an electron acceptor but it does influence the frontier and subfrontier MOs for the C60 cage, and although there is no charge transfer between I and the C60 cage, the frontier and subfrontier MOs for the C60 cage are obviously influenced by I. The stabilities DELTAE(X) (DELTAE(X) = (E(X) + E(C60)) - E(x partial derivative C60)) follow the sequence I < Br < None < Cl < F < Li < Na < K < Rb < Cs while the cage radii r follow the inverse sequence. The stability order and the cage radii order have been explained by means of the (exp-6-1) potential.

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于2010-11-23批量导入