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131.
Mathematical modeling of a bimolecular chemical reaction in the liquid phase was carried out taking account of association of both reactants. The formally simple chemical reaction is thus transformed into a multistage process, which results in the formation of temporal dissipative structures. It was found that, apart from the usual dynamic modes, there appear oscillations of the concentrations of intermediates, characterized by two considerably differing periods. 相似文献
132.
I. A. Smirnov T. S. Orlova B. I. Smirnov D. W. Wlosewicz H. Misiorek A. Jezowski T. E. Wilkes K. T. Faber 《Physics of the Solid State》2009,51(11):2264-2268
This paper reports on measurements in the 80–300-K temperature interval of the heat capacity at constant pressure C
p
(T) of high-porosity amorphous white pine carbon preforms (biocarbon) prepared by pyrolysis (carbonization) at T
carb = 1000 and 2400°C in an argon flow. The dependences C
p
(T) for biocarbon/copper composites based on the carbon preforms obtained have also been determined. It is shown that the mixture
rule holds for the composites, i.e., that C
p
(T) of the composite is a sum of the heat capacities of the constituent materials taken in the corresponding ratios. Phonon
mean free paths for the white pine carbon preforms prepared at T
carb = 1000 and 2400°C have been calculated and used to estimate the size of the nanocrystallites contributing to formation of
the carbon frameworks of these preforms. 相似文献
133.
Yu. I. Morozik E. V. Kuchinskii G. V. Galyaev A. O. Smirnov 《Journal of Analytical Chemistry》2013,68(8):680-684
A rapid and reliable method for group identification based on the fragmentation of highly toxic O-alkyl-S-2-(N,N-dialkylamino)ethyl alkyl thiophosphonates using electron-ionization mass spectra was proposed. This method makes it possible to relate a test substance to one of the four groups of compounds containing two identical alkyl substituents at the nitrogen atom (methyl, ethyl, propyl, or isopropyl). The essence of this method is that the mass spectrum of the test substance is compared with the generalized mass-spectrometric patterns of each of the four groups of this class with the aid of a standard procedure utilized in the NIST information retrieval program. 相似文献
134.
An effect of annealing in air at temperatures 250, 350, 500, and 700°C on composition, surface structure, and catalytic activity in CO oxidation of a system MnO x ,SiO2/TiO2/Ti formed by combining methods of plasma electrolytic oxidation and impregnation was examined. 相似文献
135.
136.
V. I. Smirnov V. G. Badelin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(11):1793-1797
Enthalpies of the dissolution of DL-α-alanyl-DL-norleucine are determined by calorimetry in aqueous solutions of formamide (FA), N-methylformamide (MFA), N,N-dimethylformamide (DMF), and N,N-dimethylacetamide (DMA) at a concentration of amides of x 2 = 0–0.4 molar parts and T = 298.15 K. Standard values of enthalpies of dissolution Δsol H o and Δtr H o of DL-α-alanyl-DL-norleucine transfer from water to binary solvent are calculated, along with the enthalpy coefficients of pair interactions h xy of DL-α-alanyl-DL-norleucine with amide molecules. The effect of the composition of water-organic mixtures and the structure of amides on the enthalpy characteristics of dissolution and transition of DL-α-alanyl-DL-norleucine is considered. Quantitative estimates of the contributions to energy from DL-α-alanyl-DL-norleucine-amides pair interactions determined by the polarity, polarizability, and electron acceptor and electron donor ability of organic cosolvents are given using the Kamlet-Taft correlation equation. 相似文献
137.
G. A. Pribylova I. V. Smirnov A. P. Novikov 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(1):83-87
The present paper demonstrates that room temperature ionic liquids (RTIL) added at 1–5 wt% to a diphenyl (dibutyl) carbamoylmethylphosphine oxide (Ph2Bu2) solution increase the extraction coefficients of americium from nitric acid by more than two orders of magnitude. Moreover, the use of the RTIL—1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide makes the extraction possible even from 8 M HNO3. This is an important attribute of such extraction system from the point of its possible application for radiochemical analysis of technological samples and environmental solutions, since many methods are based on transferring the solid samples into an 8 M HNO3 solution. The extraction data obtained revealed that three Ph2Bu2 ligands are included into the coordination sphere of americium, two of which represent a compound with the nitrate anion and one with the RTIL anion. 相似文献
138.
A sensitive chromatographic determination of hydrazines by naphthalene-2,3-dialdehyde derivatization
Alexander D. Smolenkov Alla V. Chernobrovkina Roman S. Smirnov Mikhail G. Chernobrovkin Oleg A. Shpigun 《International journal of environmental analytical chemistry》2013,93(12):1286-1295
A new high-performance liquid chromatography (HPLC) method for the sensitive simultaneous determination of hydrazine (Hy), monomethylhydrazine (MMH) and 1,1-dimethylhydrazine (UDMH) based upon the derivatization of hydrazines with naphthalene-2,3-dialdehyde and the separation of the derivatives on Zorbax Eclipse AAA column in a single chromatographic run under acidic conditions (pH 2.4) was developed. Hydrazine and monomethylhydrazine derivatives were found to be strongly fluorescent at λex?=?273?nm, λem?=?500?nm. It was shown that UDMH derivative can be detected as non-fluorescent hydrazone at 290?nm by UV-detection. Limits of detection were 0.05?µg?·?L?1 for Hy and MMH, and 1?µg?·?L?1 for UDMH for the injection volume of 100?µL. The method was validated for water sample analysis. It proved to be selective, accurate and precise with the supplementary advantage of the simple and rapid sample preparation. 相似文献
139.
Electrodeposition of americium on the stainless steel support for the purpose of radiochemical assay
A. P. Novikov V. S. Ryleeva A. V. Abramova G. A. Pribylova I. V. Smirnov 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(1):543-547
The kinetics of uranium, plutonium and americium electrodeposition on steel targets from organic solutions of diphenyl-(N,N-dibutyl) carbamoylmethylphosphine oxide supplemented with the ionic liquid of trihexyltetradecylphosphonium hexafluorophosphate ([PH4]+PF6 ?) in ethanol or N,N-dimethylformamide has been studied. When running a process in a dimethylformamide medium, and 0.05 M concentration of [PH4]+PF6 ? americium deposition degree exceeds 95 % at the electrolysis time of 2 h. Alpha-spectra resolution of obtained target does not exceed 40 keV. 相似文献
140.
Zaitseva Elvira R. Sokolov Anatolii I. Mikhaylov Andrey A. Baleeva Nadezhda S. Baranov Mikhail S. Smirnov Alexander Yu. 《Chemistry of Heterocyclic Compounds》2022,58(8-9):477-480
Chemistry of Heterocyclic Compounds - A methodology was developed for the synthesis of phenylspiro[imidazole-4,3'-thiochroman]ones by treatment of [2-(benzylsulfanyl)-benzylidene]imidazolones... 相似文献