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51.
Konstantin A. Kemenov Haifeng Wang Stephen B. Pope 《Combustion Theory and Modelling》2013,17(4):611-638
A posteriori analysis of the statistics of two large-eddy simulation (LES) solutions describing a piloted methane–air (Sandia D) flame is performed on a series of grids with progressively increased resolution reaching about 10.5 million cells. Chemical compositions, density and temperature fields are modelled with a steady flamelet approach and parametrised by the mixture fraction. The difference between the LES solutions arises from a different numerical treatment of the subgrid scale (SGS) mixture fraction variance – an important quantity of interest in non-premixed combustion modelling. In the first case (model I), the variance transport equation is solved directly, while in the second (model II), an equation for the square of the mixture fraction is solved, and the variance is computed from its definition. The comparison of the LES solutions is based on the convergence properties of their statistics with respect to the turbulence resolution length scale. The dependence of the LES statistics is analysed for velocity and the mixture fraction fields, and tested for convergence. For the most part, the statistics converge for the finest grids, but the variance of the mixture fraction shows some residual grid dependence in the high-gradient regions of the jet near field. The SGS variance given by model I exhibits realisability everywhere, whereas in regions of the flame model II is non-realisable, predicting negative variances. Furthermore, the LES statistics of model I exhibit superior convergence behaviour. 相似文献
52.
Victor V. Dotsenko Arif I. Ismiev Anastasiya N. Khrustaleva Konstantin A. Frolov Sergey G. Krivokolysko Elena A. Chigorina Aleksey P. Snizhko Vladimir M. Gromenko Ivan S. Bushmarinov Rizvan K. Askerov Tatyana M. Pekhtereva Sergey Yu. Suykov Elena S. Papayanina Aleksandr V. Mazepa Abel M. Magerramov 《Chemistry of Heterocyclic Compounds》2016,52(7):473-483
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Dr. Konstantin I. Galkin Bogdan Ya. Karlinskii Dr. Alexander Yu. Kostyukovich Dr. Evgeniy G. Gordeev Prof. Dr. Valentine P. Ananikov 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(39):8567-8571
This work reveals ambident nucleophilic reactivity of imidazolium cations towards carbonyl compounds at the C2 or C4 carbene centers depending on the steric properties of the substrates and reaction conditions. Such an adaptive behavior indicates the dynamic nature of organocatalysis proceeding via a covalent interaction of imidazolium carbenes with carbonyl substrates and can be explained by generation of the H-bonded ditopic carbanionic carbenes. 相似文献
57.
Baíllo Amparo Cárcamo Javier Getman Konstantin 《Advances in Data Analysis and Classification》2019,13(2):531-557
Advances in Data Analysis and Classification - The classification of the X-ray sources into classes (such as extragalactic sources, background stars,...) is an essential task in astronomy.... 相似文献
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Dr. Alexey S. Kiryutin Dr. Grit Sauer Dr. Daniel Tietze Martin Brodrecht Stephan Knecht Prof. Dr. Alexandra V. Yurkovskaya Prof. Dr. Konstantin L. Ivanov Dr. Olga Avrutina Prof. Dr. Harald Kolmar Prof. Dr. Gerd Buntkowsky 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(16):4025-4030
Two-dimensional NMR spectroscopy is one of the most important spectroscopic tools for the investigation of biological macromolecules. However, due to the low sensitivity of NMR spectroscopy, it takes usually from several minutes to many hours to record such spectra. Here, the possibility of detecting a bioactive derivative of the sunflower trypsin inhibitor-1 (SFTI-1), a tetradecapeptide, by combining parahydrogen-induced polarization (PHIP) and ultrafast 2D NMR spectroscopy is shown. The PHIP activity of the inhibitor was achieved by labeling with O-propargyl-l -tyrosine. In 1D PHIP experiments a signal enhancement of a factor of approximately 1200 compared to standard NMR was found. This enhancement permits measurement of 2D NMR correlation spectra of low-concentrated SFTI-1 in less than 10 seconds, employing ultrafast single-scan 2D NMR detection. As experimental examples PHIP-assisted ultrafast single-scan TOCSY spectra of SFTI-1 are shown. 相似文献
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Marco Reichel Mara Egenhöfer Burkhard Krumm Konstantin Karaghiosoff 《无机化学与普通化学杂志》2020,646(6):328-331
Fluoromethylating agents are a highly studied and controversely discussed class of compounds. New fluoromethyl pseudohalides FCH2N3, FCH2SCN, and FCH2SeCN were prepared for the first time and their physical and spectroscopic properties investigated. Their synthesis is performed conveniently by fluoromethylation of the respective silver or potassium pseudohalogenides with fluoroiodomethane. 相似文献
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