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161.
Mikhail V. Vener Andrei V. Churakov Alexander P. Voronin Olga D. Parashchuk Sergei V. Artobolevskii Oleg A. Alatortsev Denis E. Makhrov Alexander G. Medvedev Aleksander Filarowski 《Molecules (Basel, Switzerland)》2022,27(3)
Two new peroxosolvates of drug-like compounds were synthesized and studied by a combination of X-ray crystallographic, Raman spectroscopic methods, and periodic DFT computations. The enthalpies of H-bonds formed by hydrogen peroxide (H2O2) as a donor and an acceptor of protons were compared with the enthalpies of analogous H-bonds formed by water (H2O) in isomorphic (isostructural) hydrates. The enthalpies of H-bonds formed by H2O2 as a proton donor turned out to be higher than the values of the corresponding H-bonds formed by H2O. In the case of H2O2 as a proton acceptor in H-bonds, the ratio appeared reversed. The neutral O∙∙∙H-O/O∙∙∙H-N bonds formed by the lone electron pair of the oxygen atom of water were the strongest H-bonds in the considered crystals. In the paper, it was found out that the low-frequency Raman spectra of isomorphous crystalline hydrate and peroxosolvate of N-(5-Nitro-2-furfurylidene)-1-aminohydantoin are similar. As for the isostructural hydrate and peroxosolvate of the salt of protonated 2-amino-nicotinic acid and maleic acid monoanion, the Raman spectra are different. 相似文献
162.
Nonlinear Dynamics - In this paper, we generalize the Preisach model to the case when parameters of elementary relays are random variables. We show that an output state of the stochastic Preisach... 相似文献
163.
Vereshchagin Anatoly N. Karpenko Kirill A. Elinson Michail N. Minaeva Alexandra P. Goloveshkin Alexander S. Hansford Karl A. Egorov Mikhail P. 《Molecular diversity》2020,24(4):1327-1342
Molecular Diversity - A novel five-component diastereoselective synthesis of polysubstituted 2-piperidinones is reported. The Knoevenagel condensation–Michael addition–Mannich cascade... 相似文献
164.
Boris N. Kozlov Ivan I. Pilyugin Valerii G. Shchebelin Alexander V. Bulgakov Alexander P. Mayorov Mikhail R. Predtechenskii 《Mikrochimica acta》1995,120(1-4):111-119
A time-of-flight mass spectrometer with electron impact ionization facility was used in investigations of the laser plume structure. Densities and velocity distributions of positively charged and neutral species were measured 12 cm downstream of the target. Velocities of particles in a plume were measured by the retarding potential method. The combination of a skimmer and declining electric field was used to suppress the influence of charged particles during the measurement of the neutral component parameters. In the case of YBaCuO ceramic laser ablation, a strong variation of the laser-induced plume composition was observed from its head to its tail. It seems to be accounted for by the difference of the starting (phase transition) temperatures of various layers of a plume. Ions detected mainly in the head of a plume were followed by atoms, molecules and clusters in inverse succession to their appearance in the plume under the light intensity increase. The characteristic of the number density dependence upon the laser spot diameter make it clear that most of the molecules BaO and YO are the direct product of ablation. In contrast, the detected clusters with masses up to 2000 amu are the product of condensation in the expanding plume under the conditions of the experiments. 相似文献
165.
Violeta D. Kassabova-Zhetcheva Lilyana P. Pavlova Bisserka I. Samuneva Zara P. Cherkezova-Zheleva Ivan G. Mitov Mikhail T. Mikhov 《Central European Journal of Chemistry》2007,5(1):107-117
Structural and magnetic properties of Mg
x
Zn1−x
Fe2O4 powders have been studied with respect to the application for thermal cancer therapy (magnetic hyperthermia). Mg
x
Zn1−x
Fe2O4 (x=0.1–0.5) powders with particle sizes between 5 and 8 nm were produced by citrate method. The X-ray diffraction patterns
of the samples correspond to a spinel phase. The lattice constant and the volume of the elementary cell increase when x changes
from 0.1 to 0.5. The FTIR-spectra ascertain the spinel phase formation. The Mossbauer studies reveal the presence of extremely
small particles, which undergo superparamagnetic relaxation at room temperature. The core-shell model has been applied to
explain quadruple doublets. The quadruple splitting at “shells” is bigger than those at “cores” whereas the isomer shifts
remain close. Magnetic studies confirm the presence of extremely small particles that behave as superparamagnetic ones.
相似文献
166.
Sergei Yu Burmistrov Mikhail K. Gratchev Galina I. Kurochkina Larisa K. Vasyanina Edward E. Nifantyev 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract The effect of acid-base properties of amines hydrochlorides (AH) on their catalytic activity in methanolysis of P(III)-N-ethylaniline has been studied. The analysis of Bronsted correlation equation was indicative of general acid catalysis and it was thus confirmed, that general regularities had place during alcoholysis of P(III)-amines under catalysis with AH. In addition, the increasing of alcohol polarity leads to the increasing of proton transfer degree (α) from acid catalysts to phospho(III)amine substrate and to the increasing of the positive charge at the phosphorus in the transition state. Besides, the comparison of α values indicates that in more polar methanol (in comparison with tbutanol) the catalysis is more sensitive to the acidity change of used catalysts. 相似文献
167.
168.
In this paper, we deal with the critical problems in residue arithmetic. The reverse conversion from a Residue Number System (RNS) to positional notation is a main non-modular operation, and it constitutes a basis of other non-modular procedures used to implement various computational algorithms. We present a novel approach to the parallel reverse conversion from the residue code into a weighted number representation in the Mixed-Radix System (MRS). In our proposed method, the calculation of mixed-radix digits reduces to a parallel summation of the small word-length residues in the independent modular channels corresponding to the primary RNS moduli. The computational complexity of the developed method concerning both required modular addition operations and one-input lookup tables is estimated as , where k equals the number of used moduli. The time complexity is modular clock cycles. In pipeline mode, the throughput rate of the proposed algorithm is one reverse conversion in one modular clock cycle. 相似文献
169.
G. I. Distler S. A. Kobzareva A. N. Lobachev O. K. Melnikov N. S. Triodina 《Crystal Research and Technology》1978,13(9):1025-1034
The growth mechanism of the early formation stages of sodalite single crystals grown by the method of hydrothermal synthesis on single crystal seeds coated with interfacial layers of polycrystalline silver has been studied at an electronmicroscopic scale. Coating with interfacial layers leads to a very weak adhesion between the overgrown single crystal and the surface of the interfacial layer on top of the seed, thus providing a unique possibility of detaching the overgrown single crystals from seeds and investigating the very early crystallization stages by the morphology of the growth surface. In local microregions of seed surfaces coated with interfacial layers discrete particles arise differing from one another in morphology, this being primarily associated with the electrical heterogeneity of seed surfaces. During crystallization, the space between the discrete particles was filled with the hydrothermal solution which represented a liquid interfacial layer exhibiting informative properties occurred under the influence of electrically active elements of the seed surface. At the boundary separating the liquid interfacial layers with particular informative properties from the rest of the solution volume, at early crystallization stages, together with the formation of discrete particles directly on the coated seed surface, growth of a continuous sodalite single crystal took place. The informative properties of seed surfaces, which are regularly modified due to coating with interfacial silver layers, determine the occurrence on local regions of seed surfaces (under appropriate crystallization conditions) of one or the other polymorphous modification: either hexagonal – cancrinite, or cubic – sodalite. 相似文献
170.
Vera Yu Mishina Mikhail K. Gratchev Konstantin L. Anfilov Il'dar G. Mustafin Anna R. Bekker Edward E. Nifantyev 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract The effective methods of phosphorylation of complex systems with specifically orientated in space hydroxyl groups, namely dianhydro-D-mannitol(A), -D-sor-bitol(B), cyclodextrines(C), and cellulose(D) (A-D, where R=H), have been elaborated. 相似文献