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Barbara T. Gall Ralf Thomann Rolf Mülhaupt 《Journal of polymer science. Part A, Polymer chemistry》2011,49(11):2339-2345
iPS‐b‐PDMS‐b‐iPS triblock copolymers were prepared by hydrosilylation of vinyl‐terminated isotactic polystyrenes (iPS) with α,ω‐bis(dimethylsilane)‐terminated poly(dimethylsiloxane)s (PDMS). As a function of the molecular weights of the two components, the triblock copolymer composition was varied between 9.0 and 98 wt % iPS. The resulting triblock copolymers remained soluble during block copolymer synthesis due to slow iPS crystallization in solution. At iPS content exceeding 31 wt %, the iPS crystallization was achieved by postpolymerization annealing and melt processing. The triblock copolymers melted above 200 °C with melting temperatures very similar to those of the corresponding iPS homopolymers. Nanostructure and microstructure formation of both amorphous and semicrystalline triblock copolymers were examined by means of light microscopy, atomic force microscopy, and TEM measurements. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
975.
This paper presents a general strategy for designing adaptive space–time finite element discretizations of the nonstationary Navier–Stokes equations. The underlying framework is that of the dual weighted residual method for goal‐oriented a posteriori error estimation and automatic mesh adaptation. In this approach, the error in the approximation of certain quantities of physical interest, such as the drag coefficient, is estimated in terms of local residuals of the computed solution multiplied by sensitivity factors, which are obtained by numerically solving an associated dual problem. In the resulting local error indicators, the effects of spatial and temporal discretization are separated, which allows for the simultaneous adjustment of time step and spatial mesh size. The efficiency of the proposed method for the construction of economical meshes and the quantitative assessment of the error is illustrated by several test examples. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
976.
The lower bainite transformation is characterized by a displacive transformation from austenite to bainitic ferrite and a subsequent separation of carbon within the new supersaturated phase. At accumulations of carbon carbides precipitate. To model this complex process a framework considering phase changes and carbon diffusion is required. In this work we present a thermodynamic framework based on the theory of microforce balances considering multiphase Ginzburg-Landau equations coupled with Cahn-Hilliard diffusion. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
977.
A reduced order homogenization scheme for the case of plasticity coupled with softening effects is proposed. This is based on a straightforward extension of the so-called nonuniform transformation field analysis (NTFA, [2]). Two related new methods, denoted as uneven NTFA and adaptive NTFA accounting for accuracy improvements, are also presented, which are based on the ideas of parameter identification and adaptive modeling, respectively. A complementary numerical study is given. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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In a precedent article we constructed various topological regular parallelisms of the real projective 3-space \({{\rm PG}(3, \mathbb{R})}\) via hyperflock determining line sets of \({{\rm PG}(5, \mathbb{R})}\) (see Betten and Riesinger in Mh Math 161:43–58, 2010). In the present paper we discuss for some of these parallelisms their automorphism groups consisting of all automorphic collineations and all automorphic dualities, especially we compute their group dimension. Thus we are able to present: (1) topological regular 5-dimensional parallelisms of \({{\rm PG}(3, \mathbb{R})}\) of group dimension 0, (2) topological regular 4-dimensional parallelisms of \({{\rm PG}(3, \mathbb{R})}\) of group dimension 0 or 1, (3) topological regular 3-dimensional parallelisms of \({{\rm PG}(3, \mathbb{R})}\) of group dimension 1. 相似文献