Anionic Liposomes in Contact with Cationic Chitosan Particles

Russian Journal of General Chemistry - Nanoparticles of ionically cross-linked chitosan have been prepared from the linear polymer with weight-average molecular mass Mw of 30000, 63000, or 300000...     

Acousto-Optic Properties of Germanium-, Selenium-, Silicon-, and Tellurium-Based Alloys

Optics and Spectroscopy - Acoustic, optical, and acousto-optic properties of amorphous germanium-, selenium-, silicon-, and tellurium-based alloys have been studied. The velocities of longitudinal...     

Identification of block copolymers and determination of their purity by thin-layer chromatography

The application of adsorption, precipitation and extraction thin-layer chromatography to the identification of block copolymers, determination of their homogeneity (mixtures of homopolymers), and evaluation of their compositional homogeneity by one- and two-dimensional, multistage and gradient methods, is described. To detect the polymers on the thin-layer plate, various methods of detection are used, including those specific for each component of the block copolymer. Examples of analysis of the following block copolymers by thin-layer chromatography are reported: PS-PMMA, PS-PB, PS-PAN, PS-PBG, PI-PMS-PI, PMMA-PBMA, PMMA-PBG, PS-PEO.     

Tetrazoles: LIV. Alkylation of 5-aryltetrazoles under microwave activation

The application of microwave activation (MWA) to alkylation of 5-aryltetrazoles with dimethyl sulfate in organic solvents did not considerably affect the selectivity of the process compared to nonactivated procedure. A significant enhancement of the selectivity to the formation of N²-methyl-isomer occurred only in the alkylation in the dimethyl sulfate solution.     

Influence of the anode material on the characteristics of an analytical glow discharge cell

The energy transfer to the discharge gas due to various collision processes in the plasma and the heating of the sample are widely known effects in glow discharge (GD) spectroscopy. Despite of the considerable thermal effects and their serious influence on the performance of GD devices, measurements of the discharge gas and sample temperatures are not common at all. The gas temperature depends on the power absorption of the discharge as well as on the temperature of boundaries (sample and anode). In this work the influence of different anode materials in a Grimm-type source on the voltage–current characteristics, crater shapes and GD spectra is investigated. Anodes made of titanium and copper alloys, graphite, and steel with thermal conductivities covering a wide range of values are used. For a fixed voltage and pressure a decrease of the measured current is observed for bad thermal conductive anodes. Cooling of the sample results in an increase of the measured current. Both observations can be explained by changes of the discharge gas temperature. The temperature of the sample is measured from the back side and compared for different anodes. Further, it is found that the choice of the anode material (i) has no significant influence on the crater shape, (ii) results in slightly different sputtering rates and (iii) strong differences of the GD spectra.     

Behavior of ascorbic acid in hetero- and homophase chain-radical oxidation processes

Initiated hetorophase oxidation of cumene with oxygen was examined in the presence of ascorbic acid in a wide concentration range.     

Spline-Approximation Method Applied to Solve Natural-Vibration Problems for Rectangular Plates of Varying Thickness

The natural vibrations of anisotropic rectangular plates of varying thickness with complex boundary conditions are studied using the spline-collocation and discrete-orthogonalization methods. The basic principles of the approach are outlined. The natural vibrations of orthotropic plates with parabolically varying thickness are calculated. The results (natural frequencies and modes) obtained with different boundary conditions are analyzed __________ Translated from Prikladnaya Mekhanika, Vol. 41, No. 10, pp. 90–99, October 2005.