Rheological properties of associates of ionic monomers with micelles of oppositely charged surfactants

Rheological properties of associates formed by interaction of trimethyl[methacryl-oxyethyl]ammonium methyl sulfate with sodium octyl- and dodecyl sulfate micelles, as well as associates of sodium 4-styrenesulfonate with dodecyltrimethylammonium bromide micelles in aqueous solutions were studied by steady shear and oscillatory (dynamic) shear measurements with Fourier transform. It was shown that viscosity depends on the composition and achieves maximum value at equimolar ratio of components for two of studied systems. The extremal dependence of the viscosity vs. composition is not observed for systems with sodium octyl sulfate due to weak interactions between the components. The systems exhibiting the anomalous dependencies of concentration to viscosity are viscoelastic fluids due to the physical entanglements between the associates.     

Structural-dimensional effects and their application in the "core—nanoshell" systems synthesized by the molecular layering

In connection with the development of nanotechnology in the last 15—20 years, the method of molecular layering (ML), created in the middle of the last century in the USSR, has attracted increasing attention. The features of structural-dimensional effects in the products obtained by new chemical nanotechnology and promising directions of their practical application in "core—nanoshell" compositions are considered in the review. In accordance with the synthetic capabilities of the ML method, the functional properties of the "core—nanoshell" type materials are affected by the "monolayer effect" and the substrate shielding effect, as well as the multicomponent nature of the system, and mutual structural coordination effect of the substrate and the build-up nanolayer. The review presents theoretical and experimental data on the application of the observed effects in the creation of shell pigments and fillers, modified sorbents, catalytic membrane reactors, nanodoped ceramic materials, polymers, quartz fibers with adjustable optical characteristics, electrets, etc.     

Mass Spectrometric Analysis of Microcystins from Cyanobacterial Biomass: Optimization of the Sample Preparation Procedure

The sample preparation procedure for determination of microcystins from biomass by the LC–MS method was optimized. Treatment of freeze-dried biomass samples with acetonitrile prior to the main extraction was effectively used for decreasing the amount of protein-like matrix compounds in extracts. Use of acetonitrile–water mixtures during the main ultrasound-assisted extraction allowed increasing the total microcystins amount in the resultant extracts compared to the traditional extraction using 75% methanol.     

The effect of the system polydispersity on voltammograms of nanoparticles electrooxidation

The paper proposes a mathematical model describing electrooxidation of a polydisperse system of metal nanoparticles from the surface of an indifferent macro-electrode. It is shown that the degree of dispersion of a nanoparticle ensemble affects the shape of oxidation voltammograms. When the degree of dispersion rises and the average size of nanoparticles becomes smaller, the range of oxidation potentials increases. The results of the experimental study of electrooxidation of gold nanoparticles with different degrees of dispersion are given. The particles were localized on the surface of graphite screen-printed electrodes. A good agreement between the parameters of the experimental and calculated voltammograms confirms the correctness of the proposed model.     

ХроматограФкчеекое разделеиие изотоиов җелеза

Es werden Aufbau, Arbeitsweise und Eigenschaften einer Apparatur beschrieben, mit der natiürliche Tritium-Aktivitäten in Oberflächen- und Grundwässern gemessen werden können. Diese Messungen erfolgen in 4 Arbitsschritten: elektrolytische Anreicherung der natiärlichen Tritium-Konzentrationen, Messung des Anreicherungsfaktors mit einem Flüssigkeitsszintillationszähler, Synthese von Äthan aus dem angereicherten Probenwasser und tritiumfreiem Acetylen, Messung des Probentritiums in Äthan mit einem Proportionalzähler. Die untcre Nachweisgrenze (Meβzeit 48 Studnden, statistischer Fehler 50%) beträgt 1 T.E.     

Synthesis of 6-Mercaptohexanoylhydrazones of Mono- and Disaccharides as a Potential Glycoligands of Noble Metal Glyconanoparticles

Russian Journal of General Chemistry - The 1H and 13C NMR spectroscopy was used to study the structure of previously unknown aldose series condensation products (L-fucose, L-rhamnose, D-mannose,...     

Synthesis and Properties of Tetra(4-<Emphasis Type="Italic">tert</Emphasis>-butyl-5-phenylsulfanyl)phthalocyanines and Their Derivatives

The methods of synthesis of 4-tert-butyl-5-sulfanylphenyl-and 4-tert-butyl-5-(4'-carboxyphenylsulfanyl) phthalonitriles have been developed and on their basis the corresponding octa-substituted phthalocyanines have been prepared. The effect of the structure of the above phthalocyanine derivatives on their electronic absorption spectra and parameters of thermal degradation in the presence of air oxygen were studied.     

ИЗМЕРЕНИЯ ЭЛЕКТРОННЫХ РЕЛАКСАЦИОННЫХ ПРОЦЕССОВ В МАРГАНЦЕВЫХ ФЕРРИТАХ

The measurements of magnetic loss factor in the system Mn _x Fe_3–x O_4+y for 0.62x1.66 are described. The temperature range used was 2°K to 360°K and four fixed frequencies 75, 150, 300, and 600 kHz were employed. The results show, that three distinct processes were found with various dependences upon composition. The corresponding maxima in tg vsT curves are situated at 2°K, 10°–50°K, and 90°–350°K respectively. The connection of these processes with electron transport and/or reorientation of distortions surrounding octahedrally coordinated Mn³⁺ ions is used as a basis for an interpretation already proposed earlier.