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21.
A. G. Vendilo H. Rönkkömäki M. Hannu-Kuure M. Lajunen Y. Asikkala A. A. Petrov V. G. Krasovsky E. A. Chernikova P. Oksman L. H. J. Lajunen K. I. Popov 《Russian Journal of Coordination Chemistry》2008,34(9):635-640
The stability constants of the complex[Cs(18C6)]+ (18C6 is 18-crown-6 (L)) in N-butylpyridinium methyl sulfate (I) and of the complex [Cs(18C6)2]+ in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide (II) were measured by using 133Cs NMR spectroscopy at 23°C. It was found that logK(Cs + L) in solvent I is 1.20±0.13 and logK(CsL + L) in solvent IIis 1.18±0.05. For the complex [Cs(18C6)2]+, the dependence of its stability constant on the temperature in the 23–50°C range was obtained and the enthalpy change in the complexation was determined: ΔH(CsL + L)= ?47 kJ/mol. It was demonstrated that the enthalpy change is favorable for the formation of [Cs(18C6)2]+, while the entropy change hinders the complexation. 相似文献
22.
E. V. Chernikova N. S. Serkhacheva O. I. Smirnov N. I. Prokopov A. V. Plutalova E. A. Lysenko E. Yu. Kozhunova 《Polymer Science Series B》2016,58(6):629-639
The effect of the chain length of oligomer acrylic acid obtained in the presence of a low-molecularmass trithiocarbonate and the position of trithiocarbonate fragment (within the chain or at the chain end) on the process of emulsion polymerization of n-butyl acrylate and characteristics of the resulting dispersions has been studied for the first time. It has been found that, when using an oligomer with trithiocarbonate group located within the chain in the emulsion polymerization of n-butyl acrylate in a wide range of monomer–water phase compositions, triblock copolymers self-organizing in aqueous medium to give stable particles with the core–shell structure are formed. Oligomers with M n ~ (5–10) × 103 are optimal for synthesis of stable dispersions. In this case, block copolymers with the controlled length of hydrophobic block and a rather narrow MWD may be obtained. Thin films formed from these copolymers retain the structure of the initial dispersions on solvent removal. If the trithiocarbonate group in the oligomer is located at the chain end, the main polymerization product is a diblock copolymer. In this case, the formation of polymer–monomer particles occurs during a longer period of time, the control of MWD is weakened, and the dispersions of particles lose the aggregative stability after thin film formation. 相似文献
23.
E. V. Chernikova A. V. Plutalova K. O. Mineeva D. V. Vishnevetskii E. A. Lysenko N. S. Serkhacheva N. I. Prokopov 《Polymer Science Series B》2016,58(5):564-573
Narrowly dispersed hydrophilic block and random copolymers of acrylic acid and N-isopropylacrylamide of various compositions and molecular masses are synthesized for the first time by controlled radical polymerization via the reversible addition-fragmentation chain-transfer mechanism. The copolymers are used for the synthesis of ternary copolymers with n-butyl acrylate. As shown by dynamic light scattering, the resulting amphiphilic copolymers can form stable dispersions in diluted aqueous solutions. It is found that the effective hydrodynamic radii of dispersion particles may be controlled via variation both in the primary structure of the ternary copolymer, i.e., the amount and sequence of hydrophilic and hydrophobic units, and in the external stimuli, i.e., the temperature and pH of a solution. 相似文献
24.
Chernikova E. V. Terpugova P. S. Filippov A. N. Garina E. S. Golubev V. B. Gostev A. I. Sivtsov E. V. 《Russian Journal of Applied Chemistry》2009,82(10):1882-1889
Regular trends in controlled radical polymerization of N-vinylpyrrolidone and N-vinylsuccinimide by the mechanism of reversible chain transfer in the presence of a series of dithiobenzoates and trithiocarbonates
were studied. The possibility of preparing soluble poly-N-vinylsuccinimide in concentrated solutions using benzyl benzodithioate as reversible chain-transfer agent was demonstrated. 相似文献
25.
Deyko A Hessey SG Licence P Chernikova EA Krasovskiy VG Kustov LM Jones RG 《Physical chemistry chemical physics : PCCP》2012,14(9):3181-3193
The enthalpies of vaporisation, Δ(vap)H(298), of seven ionic liquids (ILs) (four imidazoliums, a pyridinium, a phosphonium and an isouronium) have been determined by temperature programmed desorption using line of sight mass spectrometry. They were: 1-ethyl-3-methylimidazolium bis(pentafluoroethyl)phosphinate, [C(2)C(1)Im][PO(2)(C(2)F(5))(2)]; 1-butyl-3-methylimidazolium octylsulfate, [C(4)C(1)Im][C(8)OSO(3)]; 1-butyl-3-methylimidazolium tetrafluoroborate, [C(4)C(1)Im][BF(4)]; 1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate, [C(6)C(1)Im][FAP]; 1-butylpyridinium methylsulfate, [C(4)Py][C(1)OSO(3)]; trihexyl(tetradecyl)phosphonium tetrafluoroborate, [P(6,6,6,14)][BF(4)] and O-ethyl-N,N,N',N'-tetramethylisouronium trifluoromethanesulfonate, [C(2)(C(1))(4)iU][TfO]. The values were found to be consistent with a previously proposed, predictive, model in which Δ(vap)H(298) is decomposed into a Coulombic component (computable from the IL density) and van der Waals components from the anion and cation. Two previously predicted values of Δ(vap)H(298) were found to be within 6 kJ mol(-1) of the measured experimental values. Values for the van der Waals components are tabulated for eleven cations and twelve anions. Predictions are made for Δ(vap)H(298) for 13 ILs with as yet unmeasured Δ(vap)H(298) values (using experimental molar volumes), and for a further 44 ILs using estimated molar volumes. 相似文献
26.
Laneev E. B. Chernikova N. Yu. 《Computational Mathematics and Mathematical Physics》2019,59(1):128-135
Computational Mathematics and Mathematical Physics - A method for the quantitative comparison of the spatial geometric structure of two molecules is proposed. It is based on the minimization of a... 相似文献
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29.
B. A. Poperechenko B. D. Sapozhnikov Yu. I. Belov S. O. Chernikova 《Radiophysics and Quantum Electronics》1997,40(11):924-928
A model taking into account the technical characteristics of the mechanisms, constructions, and devices of angular control
has been developed to standardize systematic angular errors in the guidance system of 64-meter TNA 1500 radio telescopes.
To define the structure of the experimental spectrum of systematic errors obtained from the data on the complex radiometric
angular standardization of the radio axis, we used an approximation algorithm based on the least squares criterion for the
set of functions which follows from the proposed model of corrections.
Experimental Design Bureau, Power Engineering Institute, Moscow; Radiophysical Research Institute, Nizhny Novgorod, Russia.
Translated from Izvestiya vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40, No. 11, pp. 1370–1377, November, 1997. 相似文献
30.