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11.
We prove the existence of fast traveling pulse solutions in excitable media with non-local coupling. Existence results had been known, until now, in the case of local, diffusive coupling and in the case of a discrete medium, with finite-range, non-local coupling. Our approach replaces methods from geometric singular perturbation theory, that had been crucial in previous existence proofs, by a PDE oriented approach, relying on exponential weights, Fredholm theory, and commutator estimates. 相似文献
12.
Dr. Peter Thumbs M. Sc. Timm T. Ensfelder M. Sc. Markus Hillmeier Dr. Mirko Wagner M. Sc. Matthias Heiss M. Sc. Constanze Scheel M. Sc. Alexander Schön Dr. Markus Müller Prof. Dr. Stylianos Michalakis Dr. Stefanie Kellner Prof. Dr. Thomas Carell 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(30):12451-12455
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Cathodic reduction of 2-azido-2,4-pentadien-1-ones under slightly protic conditions result in aminodienones, whereas under acetylating conditions only the methyl-N,N-diacetylaminoadienoates could be prepared in reasonable yields. The low reduction potential of the N,N-diacetylaminodienones leads to a mixture of by-products. The N,N-diacetylaminodienoates were studied as a model of the reduction of the azidodienes at higher reduction potentials. Dimerisation, reduction of the double-bonds and elimination of the N,N-diacetylamino group are possible reactions. The mechanism of reduction under acetylating conditions is discussed. 相似文献
15.
A new, sensitive assay for the quantitative determination of immobilized metal containing enzymes has been developed using atomic absorption spectroscopy (AAS). In contrast with conventionally used indirect methods the described quantitative AAS assay for metalloenzymes allows more exact analyses, because the carrier material with the enzyme is investigated directly. As an example, the validity and reliability of the method was examined by fixing the iron-containing enzyme catalase on cotton fabrics using different immobilization techniques. Sample preparation was carried out by dissolving the loaded fabrics in sulfuric acid before oxidising the residues with hydrogen peroxide. The iron concentrations were determined by flame atomic absorption spectrometry after calibration of the spectrometer with solutions of the free enzyme at different concentrations. 相似文献
16.
The spatiotemporal superstructure of meandering and drifting spiral waves is explained analytically. It is also demonstrated that the Hopf eigenmode that causes the transition to meandering waves is weakly exponentially localized at onset but grows exponentially slightly before onset. 相似文献
17.
We have demonstrated experimentally that polar molecules revolve around the inner electrode of a charged cylindrical capacitor in helical trajectories that result from a superposition of a translational motion along and an orbital motion around the cylinder axis. In this way molecular beams can be guided over any given distance. The results have been obtained for nozzle beams of NaCl, NaBr, and NaI seeded in Kr. The capacitor bent into a toroid may be used as a storage ring for polar molecules in high field seeking rotational states. 相似文献
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Ohne Zusammenfassung 相似文献
19.
Arnd Scheel 《Journal of Differential Equations》2008,245(1):59-79
We study multi-pulse solutions in excitable media. Under the assumption that a single pulse is asymptotically stable, we show that there is a well-defined “shooting manifold,” consisting of two pulses traveling towards each other. In phase space, the two-dimensional manifold is a graph over the manifold of linear superpositions of two pulses located at x1 and x2, with x1−x2?1. It is locally invariant under the dynamics of the reaction-diffusion system and uniformly asymptotically attracting with asymptotic phase. The main difficulty in the proof is the fact that the linearization at the leading order approximation is strongly non-autonomous since pulses approach each other with speed of order one. 相似文献
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Ohne Zusammenfassung 相似文献