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621.
We study the geometry of non-relatively hyperbolic groups. Generalizing a result of Schwartz, any quasi-isometric image of
a non-relatively hyperbolic space in a relatively hyperbolic space is contained in a bounded neighborhood of a single peripheral
subgroup. This implies that a group being relatively hyperbolic with non-relatively hyperbolic peripheral subgroups is a quasi-isometry
invariant. As an application, Artin groups are relatively hyperbolic if and only if freely decomposable. We also introduce
a new quasi-isometry invariant of metric spaces called metrically thick, which is sufficient for a metric space to be non-hyperbolic relative to any non-trivial collection of subsets. Thick finitely
generated groups include: mapping class groups of most surfaces; outer automorphism groups of most free groups; certain Artin
groups; and others. Non-uniform lattices in higher rank semisimple Lie groups are thick and hence non-relatively hyperbolic,
in contrast with rank one which provided the motivating examples of relatively hyperbolic groups. Mapping class groups are
the first examples of non-relatively hyperbolic groups having cut points in any asymptotic cone, resolving several questions
of Drutu and Sapir about the structure of relatively hyperbolic groups. Outside of group theory, Teichmüller spaces for surfaces
of sufficiently large complexity are thick with respect to the Weil–Peterson metric, in contrast with Brock–Farb’s hyperbolicity
result in low complexity. 相似文献
622.
A moving-boundary problem for concrete carbonation: Global existence and uniqueness of weak solutions 总被引:1,自引:0,他引:1
This paper deals with a one-dimensional coupled system of semi-linear parabolic equations with a kinetic condition on the moving boundary. The latter furnishes the driving force for the moving boundary. The main result is a global existence and uniqueness theorem of positive weak solutions. The system under consideration is modelled on the so-called carbonation of concrete - a prototypical chemical-corrosion process in a porous solid - concrete - which incorporates slow diffusive transport, interfacial exchange between wet and dry parts of the pores and, in particular, a fast reaction in thin layers, here idealized as a moving-boundary surface in the solid. We include simulation results showing that the model captures the qualitative behaviour of the carbonation process. 相似文献
623.
Sebastian Kolmeder Alexander Lion Ralf Landgraf Jörn Ihlemann Helena Lebsack Cornelia Kober Thomas R. Blattert 《PAMM》2012,12(1):103-104
Percutaneous vertebroplasty is a common clinical procedure to treat vertebral compression fractures and osteoporotic vertebral bodies. However, this operation technique is accompanied by different complications due to lack of knowledge about the complicated behaviour of bone cement within the human body. To contribute to a better understanding of the processes that take place inside the body during a vertebroplasty, a detailed model of the thermomechanical behaviour of acrylic bone cement has been developed. All important effects are covered, that influence the behaviour of acrylic bone cement during the injection in a human vertebral body. Implemented in the opensource CFD-code OpenFOAM®, first results show that this comprehensive simulation of the minimal invasive injection is capable to accurately predict the cement distribution and temperature field of acrylic bone cement inside the vertebral body. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
624.
625.
Désirée Sauter Martin Schröter Christoph Frey Cornelia Weber Ulrike Mersdorf Jan-Willi Janiesch Ilia Platzman Joachim P. Spatz 《Macromolecular bioscience》2023,23(8):2200437
Imitation of cellular processes in cell-like compartments is a current research focus in synthetic biology. Here, a method is introduced for assembling an artificial cytoskeleton in a synthetic cell model system based on a poly(N-isopropyl acrylamide) (PNIPAM) composite material. Toward this end, a PNIPAM-based composite material inside water-in-oil droplets that are stabilized with PNIPAM-functionalized and commercial fluorosurfactants is introduced. The temperature-mediated contraction/release behavior of the PNIPAM-based cytoskeleton is investigated. The reversibility of the PNIPAM transition is further examined in bulk and in droplets and it could be shown that hydrogel induced deformation could be used to controllably manipulate droplet-based synthetic cell motility upon temperature changes. It is envisioned that a combination of the presented artificial cytoskeleton with naturally occurring components might expand the bandwidth of the bottom-up synthetic biology. 相似文献
626.
Ralf Landgraf Jörn Ihlemann Sebastian Kolmeder Alexander Lion Helena Lebsack Cornelia Kober Werner Schmölz Thomas R. Blattert 《PAMM》2014,14(1):121-122
This contribution deals with the simulation based investigation of processes related to the surgical treatment of vertebroplasty. In this regard, a simulation framework has been developed, which includes the generation of microstructural computer models of cancellous bone structures, the simulation of bone cement injection by computational fluid dynamics (CFD) methods and finite element (FE) simulations of bone cement curing processes. The modelling and computation strategy is illustrated and different material modelling approaches for the representation of acrylic bone cements as a non-linear fluid and a non-linear viscoelastic solid with curing dependent properties are outlined. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
627.
Cornelia Kasper 《Nachrichten aus der Chemie》2001,49(9):1073-1075
628.
629.
John Peter Coats Rémy Cochereau Ionel Adrian Dinu Daniel Messmer Flavien Sciortino Cornelia. G. Palivan 《Macromolecular bioscience》2023,23(8):2200474
Polymeric nano- and microscale materials bear significant potential in manifold applications related to biomedicine. This is owed not only to the large chemical diversity of the constituent polymers, but also to the various morphologies these materials can achieve, ranging from simple particles to intricate self-assembled structures. Modern synthetic polymer chemistry permits the tuning of many physicochemical parameters affecting the behavior of polymeric nano- and microscale materials in the biological context. In this Perspective, an overview of the synthetic principles underlying the modern preparation of these materials is provided, aiming to demonstrate how advances in and ingenious implementations of polymer chemistry fuel a range of applications, both present and prospective. 相似文献