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G. M. Pavlov G. F. Kolbina I. I. Gavrilova E. F. Panarin 《Polymer Science Series A》2010,52(2):115-118
For samples of various molecular masses, the flow birefringence of poly(styrene-4-sulfonate sodium) macromolecules in aqueous
solutions at various ionic strengths is studied in relation to the concentration of NaCl. It is shown that the sign of birefringence
changes from negative to positive with an increase in the ionic strength of a solution. Application of the macroform theory
to the Maxwell effect makes it possible to estimate the intrinsic optical anisotropy of the repeating unit of poly(styrene-4-sulfonate
sodium) (a||- a⊥) = −17 × 10-25 cm3), which nearly coincides with similar values known for atactic polystyrene and poly(κ-methylstyrene). 相似文献
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N. A. Bodunov S. A. Kolbina S. Yu. Pilyugin 《Vestnik St. Petersburg University: Mathematics》2012,45(2):61-64
The problem of local parameter identifiability of an ??input-output?? system is considered. It is shown that if the dimension of the parameter space is not higher than that of the space of output signals, then a generic system is locally parameter identifiable for almost all values of the input signal and parameter. We give an example which illustrates that if the number of parameters exceeds the dimension of the output signal, then the corresponding assertion ceases to be true. 相似文献
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V.N. Tsvetkov K.A. Andrianov E.I. Riumtsev I.N. Shtennikova N.V. Pogodina G.F. Kolbina N.N. Makarova 《European Polymer Journal》1975,11(11):771-778
Flow birefringence (FBR) and electric birefringence (EBR) have been investigated for dilute solutions of a number of fractions of cyclolinear (ladder) polychlorophenylsilsesquioxane (CLChPhS). FBR and EBR are negative in sign and their characteristic values increase with molecular weight in accordance with properties characteristic of kinetically and equilibrium—rigid chain polymers. In sinusoidal fields, dispersion of EBR characteristic of kinetically rigid chains was found: its dependence on molecular weight quantitatively agrees with the theory of relaxation and rotatory friction of rigid molecules. Analysis of experimental data confirms the validity of the molecular model of CIChPhS as a double-chain ladder cis-structure and permits us to obtain quantitative information concerning important molecular parameters such as the character of rotation of phenyl side groups the values of valence angles in chains and in oxygen bridges and dipole moments of the monomer unit of the chain and of the SiO bond. 相似文献
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Sarapulova G. I. Rozinova L. G. Rozinov V. G. Kolbina V. E. 《Russian Journal of Organic Chemistry》2002,38(9):1266-1270
Reactions of new enehydrazides, N',N'-dimethyl-N-vinylpropenohydrazide and N',N'-dimethyl-N-vinylbenzohydrazide with chloroform, phenol, and hydrogen chloride in carbon tetrachloride were studied by IR spectroscopy. In the first two cases, molecular complexes are formed between the hydrazide and proton donor. The reaction of N',N'-dimethyl-N-vinylpropenohydrazide with HCl results in formation of dihydropyrazole derivative which exists as a tautomeric mixture of the major lactam and minor lactim forms. N',N'-dimethyl-N-vinylbenzohydrazide reacts with hydrogen chloride to give protonated form in which proton is localized on the amino nitrogen atom. The structure of the initial compounds and the products was analyzed in terms of AM1 quantum-chemical calculations. 相似文献
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Shtennikova I. N. Bushin S. V. Kolbina G. F. Khotimskii V. S. Litvinova E. G. Chirkova M. V. 《Russian Journal of Applied Chemistry》2002,75(8):1308-1311
Hydrodynamic properties of 10 samples of poly(1-trimethylsilylpropyne) of various molecular weights, obtained with NbCl5 catalyst and containing 60-70% cis C = C bonds, were studied by sedimentation, translation diffusion, and viscometry techniques. The equilibrium rigidity of the polymer molecules was estimated from the viscometric data using the formalism of the intrinsic viscosity theory as applied to the worm-like coil model with excluded-volume effects. For the polymer macromolecules, the Kuhn segment length, thermodynamic parameter , and hydrodynamic diameter of the chain d were estimated. 相似文献
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Optical properties of poly-(1-trimethylsilyl-1-propyne) in solvents with different refractive indices and optical anisotropies have been studied by the dynamic birefringence method. An optical shape-effect has been detected in solvents characterized by refractive indices ns different from those of dry polymer nk. It was revealed that this effect is an effect of the macromolecule segment shape; this allowed us to estimate thermodynamic rigidity of the molecular chains under study (A = 82 × 10−8 cm). It has been found that the optical shear coefficient of the studied polymers solutions in anisotropic solvents exceeds considerably the same parameter in an isotropic solvent. It has been shown that this difference is caused by the solvent anisotropic molecules orientation by the axis of maximal polarizability along the macromolecule backbone. The assumption that the solvent molecules orientation order with respect to chain molecules does not depend on the chain molecule thermodynamic rigidity allowed us to obtain independent estimate of the sizes of static segments of the macromolecules under study (98 × 10−8 cm). 相似文献
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G. M. Pavlov A. S. Gubarev G. F. Kolbina I. P. Kolomiets A. L. Didenko V. M. Svetlichnyi 《Polymer Science Series A》2017,59(2):193-197
Birefringence in solutions and films of poly[4,4'-bis(4''-N-phenoxy)diphenylsulfon]imide of 1,3-bis(3',4-dicarboxyphenoxy)benzene macromolecules is studied. The method of birefringence in the flow of polymer solutions in DMF allows one to determine the proper specific optical anisotropy of the repeating unit of chain βM = +15 × 10–27 cm3 mol/g. Spontaneous birefringence in polymer films of different thickness is studied under various incidence angles of a polarized beam. The total data analysis allows one to estimate the orientation order parameter of polymer chain fragments in the vicinity of surface S 0 =–0.01, which is typical of flexible-chain polymers. 相似文献