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This study summarizes the scaling behavior of single laminar submerged jets with circular and planar cross sections. Unified correlations for the stagnation zone heat transfer of both configurations, based on the dominant dimensionless numbers, are presented. In technical applications, impinging jets are often applied in jet array configurations. Compared to single jet impingement, jet-to-jet interaction can have a substantial influence on local heat transfer. A distinct pattern of the heat transfer coefficient was observed experimentally. Numerical simulations revealed two counter-rotating vortices in the interaction zone between two jets to be the causing mechanism of this pattern. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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J. Rohlfs 《Inventiones Mathematicae》1978,48(2):185-205
Ohne Zusammenfassung 相似文献
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J. Rohlfs 《Mathematische Annalen》1979,244(3):219-231
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Wilko Rohlfs Georg F. Dietze Herman D. Haustein Reinhold Kneer 《Journal of computational physics》2012,231(12):4454-4463
This comment refers to the article of Tomar et al. [1], which presents a numerical methodology of a continuum surface force formulation for simulating two-phase electrohydrodynamic flows. The present work shows, that due to the diffusive character of the Laplacian equation (? · (??0E) = 0) with discontinuous physical properties (?(x, y, z)), different averaging methods (arithmetic and harmonic) for the fluid property in the transition region have to be applied. The correct choice of the averaging method depends on the orientation of the flux to the interface.An additional improvement is made by calculating the electric displacement D at the cell faces. This leads to a numerical solution independent of the spatial resolution as well as of the interfacial smearing. Simulation results of two different test cases show that the error of the numerical solution is in the order of machine precision. 相似文献
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J. Rohlfs 《Mathematische Annalen》1978,234(3):239-252
Ohne Zusammenfassung 相似文献
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Kiichirou?Koyasu Wilko?Westh?user Marco?Niemietz Jan?Heinen Gerd?Gantef?r 《Applied Physics A: Materials Science & Processing》2009,96(3):679-684
Using time-resolved photoelectron spectroscopy, the decay channels of AuO2− and Au2O2− following photoexcitation with 3.1-eV photons have been studied. For AuO2−, a state with a rather long lifetime of 30 ps has been identified. Its decay path could not be determined but photodesorption
can be excluded. For Au2O2−, the spectra indicate O2 desorption after 3.1-eV photoexcitation on a time scale of 1 ps. While comparing these results on Au
n
O2− with analogous data on Ag
n
O2− clusters, a discernible pattern emerges: for dissociatively bound O2(AuO2−, Ag3O2−), there are long-living excited states which do not decay by oxygen desorption, while for molecular chemisorption (Au2O2−, Ag2O2−, Ag4O2−, Ag8O2−), the 3.1-eV photoexcitation triggers fast O2 desorption with a high quantum yield. 相似文献
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Wilko Greschner Beate Neumann Dr. Hans‐Georg Stammler Prof. Dr. Harald Gröger Prof. Dr. Dietmar Kuck 《Angewandte Chemie (International ed. in English)》2015,54(46):13764-13768
Inherently chiral acetophenones and benzaldehydes bearing the large, bowl‐shaped framework of tribenzotriquinacene (TBTQ) were synthesized in enantiomerically pure form employing enzyme catalysis. Five‐step sequences involving lipase CAL‐B lead to the (M)‐enantiomers, (+)‐2‐acetyl‐TBTQ (M)‐ 5 and (+)‐2‐formyl‐TBTQ (M)‐ 6 , whereas use of lipase PS leads to the (P)‐enantiomers, (?)‐2‐acetyl‐TBTQ (P)‐ 5 and (?)‐2‐formyl‐TBTQ (P)‐ 6 , with at least 99 % ee in each case. The absolute configuration of these rigid 3D building blocks was determined by X‐ray diffraction analysis of the ketones 5 and by comparison of their chiroptical properties with those of the aldehydes 6 . 相似文献