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991.
Sustainability of Environment‐Assisted Energy Transfer in Quantum Photobiological Complexes 下载免费PDF全文
Konstantin G. Zloshchastiev 《Annalen der Physik》2017,529(9)
It is shown that quantum sustainability is a universal phenomenon which emerges during environment‐assisted electronic excitation energy transfer (EET) in photobiological complexes (PBCs), such as photosynthetic reaction centers and centers of melanogenesis. We demonstrate that quantum photobiological systems must be sustainable for them to simultaneously endure continuous energy transfer and keep their internal structure from destruction or critical instability. These quantum effects occur due to the interaction of PBCs with their environment which can be described by means of the reduced density operator and effective non‐Hermitian Hamiltonian (NH). Sustainable NH models of EET predict the coherence beats, followed by the decrease of coherence down to a small, yet non‐zero value. This indicates that in sustainable PBCs, quantum effects survive on a much larger time scale than the energy relaxation of an exciton. We show that sustainable evolution significantly lowers the entropy of PBCs and improves the speed and capacity of EET. 相似文献
992.
Large-scale strain rate field, a resolved quantity which is easily computable in large-eddy simulations (LES), could have profound effects on the premixed flame properties by altering the turbulent flame speed and inducing local extinction. The role of the resolved strain rate has been investigated in a posterior LES study of GE lean premixed dry low-NOx emissions LM6000 gas turbine combustor model. A novel approach which is based on the coupling of the linear-eddy model with a one-dimensional counterflow solver has been applied to obtain the parameterizations of the resolved premixed flame properties in terms of the reactive progress variable, the local strain rate measure, and local Reynolds and Karlovitz numbers. The strain rate effects have been analyzed by comparing LES statistics for several models of the turbulent flame speed, i.e, with and without accounting for the local strain rate effects, with available experimental data. The sensitivity of the simulation results to the inflow velocity conditions as well as the grid resolution have been also studied. Overall, the results obtained demonstrate that the effects of the resolved strain rate are not dominant for the considered premixed flame configuration and the unstrained turbulent flame speed model is found to perform as well as the one that allows for the strain rate effects. 相似文献
993.
Yerbol K. Akhmetbekov Sergey V. Alekseenko Vladimir M. Dulin Dmitriy M. Markovich Konstantin S. Pervunin 《Experiments in fluids》2010,48(4):615-629
A correlation-based processing algorithm for bubble identification by a planar fluorescence for bubble imaging (PFBI) technique
is presented in this paper. The algorithm includes procedures to identify bubble positions and sizes, as well as to track
bubbles and correct bubble displacement vectors. Moreover, several schemes for calculation time optimisation were realised
to achieve a reliable calculation time. The developed algorithm identifies and tracks overlapping bubble images or images
with non-uniform intensity distributions. The employed correlation and iterative passing approach provides sub-pixel accuracy
of bubble displacement estimation. In addition, the presented algorithm for bubble ring detection can be easily applied to
shadow photography images of bubbles, after the application of a derivative filter. The PFBI technique, combined with the
particle image velocimetry and particle tracking velocimetry algorithms, was applied for the experimental study of bubbly
free jet two-phase flows at Re = 12,000. Four cases of volumetric gas content in the jet core were studied: 0, 1.2, 2.4 and 4.2%, with the same mean bubble
diameter—0.85 mm. The developed technique measures two-dimensional distributions of instantaneous void fractions, as well
as both gaseous and liquid-phase velocities. Consequently, the mean void fraction and velocity fields and a set of second-order
statistical moments were obtained, including correlations of void fraction and velocity pulsations. It was shown that the
increase in volumetric gas content leads to the suppression of liquid-phase velocity fluctuations in the jet mixing layer. 相似文献
994.
Joachim Heinicke Nidhi Gupta Shreeyukta Singh Anushka Surana Olaf Kühl Raj K. Bansal Konstantin Karaghiosoff Martin Vogt 《无机化学与普通化学杂志》2002,628(13):2869-2876
1H‐1, 3‐Benzazaphospholes react with M(CO)5(THF) (M = Cr, Mo, W) to give thermally and relatively air stable η1‐(1H‐1, 3‐Benzazaphosphole‐P)M(CO)5 complexes. The 1H‐ and 13C‐NMR‐data are in accordance with the preservation of the phosphaaromatic π‐system of the ligand. The strong upfield 31P coordination shift, particularly of the Mo and W complexes, forms a contrast to the downfield‐shifts of phosphine‐M(CO)5 complexes and classifies benzazaphospholes as weak donor but efficient acceptor ligands. Nickelocene reacts as organometallic species with metalation of the NH‐function. The resulting ambident 1, 3‐benzazaphospholide anions prefer a μ2‐coordination of the η5‐CpNi‐fragment at phosphorus to coordination at nitrogen or a η3‐heteroallyl‐η5‐CpNi‐semisandwich structure. This is shown by characteristic NMR data and the crystal structure analysis of a η5‐CpNi‐benzazaphospholide. The latter is a P‐bridging dimer with a planar Ni2P2 ring and trans‐configuration of the two planar heterocyclic phosphido ligands arranged perpendicular to the four‐membered ring. 相似文献
995.
Dr. Sergei I. Ivlev Konstantin Gaul Mengyi Chen Prof. Dr. Antti J. Karttunen Prof. Dr. Robert Berger Prof. Dr. Florian Kraus 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(22):5793-5802
[Br3][SbF6] and [Br3][IrF6] were synthesized by interaction of BrF3 with Sb2O3 or iridium metal, respectively. The former compound crystallizes in the orthorhombic space group Pbcn (No. 60) with a=11.9269(7), b=11.5370(7), c=12.0640(6) Å, V=1660.01(16) Å3, Z=8 at 100 K. The latter compound crystallizes in the triclinic space group P (No. 2) with a=5.4686(5), b=7.6861(8), c=9.9830(9) Å, α=85.320(8), β=82.060(7), γ=78.466(7)°, V=406.56(7) Å3, Z=2 at 100 K. Both compounds contain the cation [Br3]+, which has a bent structure and is coordinated by octahedron-like anions [MF6]− (M=Sb, Ir). Experimentally obtained cell parameters, bond lengths, and angles are confirmed by solid-state DFT calculations, which differ from the experimental values by less than 2 %. Relativistic effects on the structure of the tribromonium(1+) cation are studied computationally and found to be small. For the heaviest analogues containing At and Ts, however, pronounced relativistic effects are found, which lead to a linear structure of the polyhalogen cation. 相似文献
996.
Teterin Yuri A. Kazakov Andrey G. Teterin Anton Yu Severin Alexander V. Dvorak Stanislav V. Maslakov Konstantin I. Ivanov Kirill E. 《Journal of Radioanalytical and Nuclear Chemistry》2019,321(1):341-347
Journal of Radioanalytical and Nuclear Chemistry - Elemental and phase composition of hydroxyapatite (HA) nanoparticle surface with absorbed zirconium were studied with X-ray photoelectron... 相似文献
997.
Matteo Andrea Lucherelli Dr. Jésus Raya Konstantin F. Edelthalhammer Dr. Frank Hauke Prof. Andreas Hirsch Dr. Gonzalo Abellán Dr. Alberto Bianco 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(57):13218-13223
Graphene has been covalently functionalized through a one-pot reductive pathway using graphite intercalation compounds (GICs), in particular KC8, with three different orthogonally protected derivatives of 4-aminobenzylamine. This novel multifunctional platform exhibits excellent bulk functionalization homogeneity (Hbulk) and degree of addition while preserving the chemical functionalities of the organic addends through different protecting groups, namely: tert-butyloxycarbonyl (Boc), benzyloxycarbonyl (Cbz) and phthalimide (Pht). We have employed (temperature-dependent) statistical Raman spectroscopy (SRS), X-ray photoelectron spectroscopy (XPS), magic angle spinning solid state 13C NMR (MAS-NMR), and a characterization tool consisting of thermogravimetric analysis coupled with gas chromatography and mass spectrometry (TG-GC-MS) to unambiguously demonstrate the covalent binding and the chemical nature of the different molecular linkers. This work paves the way for the development of smart graphene-based materials of great interest in biomedicine or electronics, to name a few, and will serve as a guide in the design of new 2D multifunctional materials. 相似文献
998.
999.
Glukhova Irina Asabina Elena Pet’kov Vladimir Kovalsky Andrey Pokholok Konstantin 《Journal of Sol-Gel Science and Technology》2021,99(2):354-365
Journal of Sol-Gel Science and Technology - The series M0.5(1+x)FexZr2?x(PO4)3 (M—Ni, Cu, Mn) with Sc2(WO4)3-related structure (SW) were prepared using Pechini technique and... 相似文献
1000.
Dr. Yulia Yu. Enakieva Dr. Anna A. Sinelshchikova Prof. Mikhail S. Grigoriev Prof. Vladimir V. Chernyshev Dr. Konstantin A. Kovalenko Prof. Irina A. Stenina Prof. Andrey B. Yaroslavtsev Prof. Yulia G. Gorbunova Prof. Aslan Yu. Tsivadze 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(5):1598-1602
A novel metal–organic framework [Zn3(Ni-H2TPPP)(Ni-H4TPPP)(Ni-H5TPPP) ⋅ 7(CH3)2NH2 ⋅ DMF ⋅ 7 H2O] (where Ni-HxTPPP (x=2,4,5) are partially deprotonated [5,10,15,20-tetrakis(3-(phosphonatophenyl)-porphyrinato(2-))]nickel(II) species), IPCE-2Ni , with outstanding proton conductivity (1.0×10−2 S cm−1 at 75 °C and 95 % relative humidity) has been obtained. The high concentration of free phosphonate groups and compensating dimethylammonium cations bound by hydrogen bonds in the unique crystal structure of IPCE-2Ni is a key factor responsible for the observed high proton conductivity, which is one order of magnitude higher than for the corresponding MOF based on 5,10,15,20-tetrakis(4-(phosphonatophenyl)porphyrinato(2-))]nickel(II) IPCE-1Ni and comparable with that of leaders among MOFs. 相似文献