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E. Soppa S. Schmauder G. Fischer J. Thesing R. Ritter 《Computational Materials Science》1999,16(1-4):323-332
In this contribution, investigations of the influence of the microstructure on the macro-, meso- and micro-effects in metal–matrix composites are presented by direct combination of experiment and simulation. The aim of the presented work consists in an improved understanding of the mechanical behaviour of heterogeneous materials by combining information of different length scales. 相似文献
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Tobias Fischer Luuk J. G. W. van Wilderen Petra Gnau Jens Bredenbeck Lars-Oliver Essen Josef Wachtveitl Chavdar Slavov 《International journal of molecular sciences》2021,22(19)
The family of phytochrome photoreceptors contains proteins with different domain architectures and spectral properties. Knotless phytochromes are one of the three main subgroups classified by their distinct lack of the PAS domain in their photosensory core module, which is in contrast to the canonical PAS-GAF-PHY array. Despite intensive research on the ultrafast photodynamics of phytochromes, little is known about the primary kinetics in knotless phytochromes. Here, we present the ultrafast Pr ⇆ Pfr photodynamics of SynCph2, the best-known knotless phytochrome. Our results show that the excited state lifetime of Pr* (~200 ps) is similar to bacteriophytochromes, but much longer than in most canonical phytochromes. We assign the slow Pr* kinetics to relaxation processes of the chromophore-binding pocket that controls the bilin chromophore’s isomerization step. The Pfr photoconversion dynamics starts with a faster excited state relaxation than in canonical phytochromes, but, despite the differences in the respective domain architectures, proceeds via similar ground state intermediate steps up to Meta-F. Based on our observations, we propose that the kinetic features and overall dynamics of the ultrafast photoreaction are determined to a great extent by the geometrical context (i.e., available space and flexibility) within the binding pocket, while the general reaction steps following the photoexcitation are most likely conserved among the red/far-red phytochromes. 相似文献
996.
M. Stuber M. A. Spiegel S. E. Fischer M. B. Scheidegger P. G. Danias E. M. Pedersen P. Boesiger 《Magma (New York, N.Y.)》1999,9(1-2):85-91
Myocardial tagging has shown to be a useful magnetic resonance modality for the assessment and quantification of local myocardial
function. Many myocardial tagging techniques suffer from a rapid fading of the tags, restricting their application mainly
to systolic phases of the cardiac cycle. However, left ventricular diastolic dysfunction has been increasingly appreciated
as a major cause of heart failure. Subtraction based slice-following CSPAMM myocardial tagging has shown to overcome limitations
such as fading of the tags. Remaining impediments, to this technique, however, are extensive scanning times (∼10 min), the
requirement of repeated breath-holds using a coached breathing pattern, and the enhanced sensitivity of artifacts related
to poor patient compliance or inconsistent depths of end-expiratory breath-holds. We therefore propose a combination of slice-following
CSPAMM myocardial tagging with a segmented EPI imaging sequence. Together with an optimized RF excitation scheme, this enables
to acquire as many as 20 systolic and diastolic grid-tagged images per cardiac cycle with a high tagging contrast during a
short period of sustained respiration. 相似文献
997.
VitaliI. Tararov Renat Kadyrov ThomasH. Riermeier Christine Fischer Armin Brner 《Advanced Synthesis \u0026amp; Catalysis》2004,346(5):561-565
The direct reductive amination of acetophenone with benzylamine or piperidine was studied in comparison with the hydrogenation of possible intermediates like a corresponding imine or enamine. No common features in terms of productivity and stereocontrol (in the case of chiral catalysts) have been found for both processes. Hence evaluation of efficient, selective and enantioselective catalysts for direct reductive amination appears to be a separate task. 相似文献
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Long‐term experiences with a cathodic protection system for steel in concrete In 1986 in Germany the first cathodic protection system for reinforced concrete structures was put into service. Installation, commissioning and the regular monitoring were scientifically supported. Due to necessary traffic related reconstruction measures the system was switch off after 15 years of service. Investigations carried out during that period should verify laboratory test results at a real structure and furthermore yield information on the long‐term behaviour concerning durability, temperature dependence, potential distribution, chloride migration etc. With increasing time of service the protection criteria could only be met by increasing the transformer rectifier voltage (the system worked in the constant voltage mode). Extensive investigations of the anode material (conductive polymer wire with a copper core) after 15 years of service showed that irreversible changes substantially decreased the polymer's conductivity limiting the functionality. Today, these kind of anodes are not used any more for the application in cathodic protection systems of reinforced concrete structures. 相似文献