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V. K. Voronkova R. T. Galeev S. Shova G. Novitchi C. I. Turta A. Caneschi D. Gatteschi J. Lipkowski Yu. A. Simonov 《Applied magnetic resonance》2003,25(2):227-247
New compounds, [Cu3Ln2(ClCH2COO)12(H2O)8]·2H2O with Ln = Nd3+ (I), Sm3+ (II), Pr3+ (III), built up of pentanuclear clusters were synthesized and studied by means of X-ray analysis and electron paramagnetic
resonance (EPR). X-ray data show that all compounds are isostructural and the pentanuclear clusteres may be considered as
a linear system with alternating Cu(II) and Ln(III) ions: Cu(2)-L1-Ln-L2-Cu(1)-L2-Ln-L2-Cu(2) with L1 and L2 being bridging fragments and Cu(1) and Cu(2) being structurally nonequivalent copper complexes. EPR studies demonstrate that
in the temperature range of 100–293 K the signals due to only one type of the copper complexes are observed in the spectra
of I–III. AtT<100 K the spectral temperature dependence is nontrivial. AtT<30 K new signals are detected in the spectra of I and II. The temperature dependence of the EPR spectra is interpreted under
the assumption that the parameter of the exchange interaction Cu(2)-Ln considerably exceeds the parameter of the interaction
Cu(1)-Ln. EPR spectra are calculated for the fragments of five paramagnetic centers in the frames of the model taking into
account the nonequivalence of two copper complexes, short longitudinal and transverse paramagnetic relaxation times of the
rare-earth ions at room temperature and the change of the relaxation rates when the temperature decreases. The results of
the calculations show that it is possible to obtain information about the interactions in the system on the basis of the analysis
of the temperature dependence of the EPR spectra of the central copper complex. The parameter of the isotropic part of the
exchange interaction between copper and neodymium ions (for the interaction Cu(2)-Nd) is estimated as about 15 cm−1. A considerable rearrangement of the spin states when the temperature changes is found for all complexes. 相似文献
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A. A. Galeev 《Journal of Applied Mechanics and Technical Physics》1965,6(3):25-27
A thermodynamically nonequilibrium fluid tends to return to its stable equilibrium state owing to the dissipation and redistribution of part of its energy as a result of individual particle collisions. However, if the fluid deviates strongly from the state of thermodynamic equilibrium, it is more advantageous for it to go over into a stare of random motion, which permits the more rapid liquidation of the non-equilibrium condition in the active development of turbulent transfer processes exceeding in magnitude the classical processes of molecular transfer. Finding the spectrum and energy level of the resulting turbulent motion is a complex and, in some cases, mathematically impossible task. Therefore it is useful to have at least some restraints on their magnitudes, in order to be able to estimate the role of turbulent transfer processes in the pattern of evolution of the unstable state of the fluid. As these conditions we shall take the conditions of stability of the steady turbulent state of the fluid. 相似文献
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Glushkov V. A. Shemyakina D. A. Zhukova N. K. Pavlogradskaya L. V. Dmitriev M. V. Eroshenko D. V. Galeev A. R. Mokrushin I. G. 《Russian Journal of Organic Chemistry》2019,55(11):1690-1697
Russian Journal of Organic Chemistry - The reaction of 30-bromo-3β,28-diacylbetulin with sodium azide afforded 30-azido-3β,28-diacyloxylup-20(29)-enes. The products were subjected to a... 相似文献
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Barney?L.?BalesEmail author M.?M.?Bakirov R.?T.?Galeev I.?A.?Kirilyuk A.?I.?Kokorin K.?M.?Salikhov 《Applied magnetic resonance》2017,48(11-12):1399-1445
Experimental studies of 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (Tempol) in 60 wt% aqueous glycerol were carried out for temperatures from 273 to 340 K. Selective isotope substitution allowed comparisons between the experimental spectral manifestations of spin exchange and dipole–dipole interactions for protonated, deuterated, 15N, and 14N Tempol. Theoretical spectra were computed from a rigorous theory specifically formulated to include proton hyperfine interactions over a wide range of spin exchange and dipole–dipole interactions to compare with the experimental data. For spin exchange and dipole–dipole interactions small compared with the proton hyperfine coupling constant, spectra were calculated with perturbation theory to gain insight into the behavior of individual proton lines. The theoretical and experimental spectra were analyzed by least-squares fitting to Voigt shapes or by a new two-point method. For most accessible experimental designs, the comparisons are rather good; however, for an experiment constrained to low concentrations and high viscosities, the methods are less accurate. 相似文献
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Constantin Romanescu Timur R. Galeev Wei‐Li Li Alexander I. Boldyrev Lai‐Sheng Wang 《ChemInform》2012,43(2):no-no
Co@B‐8, Ru@B‐9, Co@B8, and Ru@B9 clusters are characterized by photoelectron spectroscopy and DFT calculations. 相似文献