Sodegaura, Japan
Sodegaura, Japan

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Shinohara Y.,University of Tokyo | Yamazoe K.,University of Tokyo | Sakurai T.,Sumitomo Chemicals Co. | Kimata S.,Sumitomo Chemicals Co. | And 2 more authors.
Macromolecules | Year: 2012

Relationship between the structure of injection-molded isotactic polypropylene and its tensile mechanical properties, necking and fracture behaviors in particular, was investigated in terms of micrometer-scale structural inhomogeneity of nanometer- and subnanometer-scale structures. To clarify the micrometer-scale inhomogeneity, we employed scanning microbeam wide-angle X-ray diffraction and small-angle X-ray scattering technique. Four isotactic polypropylene samples were studied, produced using different injection-condition and thermal treatments. The results of scanning microbeam X-ray scattering measurements showed the presence of two types of micrometer-scale structural inhomogeneity in addition to the orientation of molecules: the distribution of polymorphs and of crystalline ordering. The results of scanning microbeam X-ray scattering of deformed sample showed the disappearance of the β-form isotactic polypropylene crystals at the outer regions accompanied by the plastic deformation. It is indicated that the inhomogeneous distribution of crystalline ordering and the existence of different polymorphs are highly related to the tensile mechanical behavior. © 2012 American Chemical Society.

Fujisawa K.,Ibaraki University | Nabika M.,Sumitomo Chemicals Co.
Coordination Chemistry Reviews | Year: 2013

Many transition metal catalysts including both early and late transition metal ions have been investigated for olefin polymerization and copolymerization reactions. Less attention has been paid to group 7 metal catalysts. Yet, manganese(II)-based catalysts are expected to have features distinct from early and late transition metal catalysts. In this context, the present review summarizes our recent results and strategy about ethylene polymerization and ethylene copolymerization with 1-hexene with manganese(II)-based catalysts. © 2012 Elsevier B.V..

Cole J.B.,University of Tsukuba | Banerjee S.,Sumitomo Chemicals Ltd.
Annual Review of Progress in Applied Computational Electromagnetics | Year: 2015

The nonstandard (NS) finite difference time domain (FDTD) algorithm delivers high accuracy on a coarse numerical grid, but in many problems the dominant source of error is the representation of objects on the grid. The error due to the representation is especially large near resonances. In this paper we address some methods to reduce representation error based on Mie theory on the theory of layers.

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