Effect of Polyglycol Ethers on the Frictional Properties of a Hemispherical Yarn

Russian Journal of General Chemistry - The effect of polyglycol ethers on the frictional properties of a 22 tex 35%wool/65% polyester fiber blend yarn was examined. During external friction the...     

The Effect of Irradiation of a Titanium Alloy of the Ti–6Al–4V–Н System with Pulsed Electron Beams on Its Creep

Russian Physics Journal - Comparative studies of the effect of pulsed electron beam irradiation of the Ti–6Al–4V titanium alloys with the contents of hydrogen of 0.002 wt.% (VT6 alloy)...     

A new approach to synthesis of organic/inorganic nanocomposites

The possibility of preparation of nanocomposite materials with improved physicomechanical properties by polycondensation of spirocyclic silicates and diisocyanates was elucidated. The thermomechanical, spectral, and thermogravimetric properties of the resulting materials were examined.     

Aliphatic polyurethane-silica nanocomposites prepared by the parallel synthesis: Morphology and mechanical characteristics

Films of aliphatic polyurethane-silica composites containing up to 27.3 mol % of SiO₂ nanoparticles have been prepared by the parallel synthesis using the sol-gel technology. It has been revealed that the variations in the mechanical properties of these materials with increasing concentration of nanoparticles exhibit a nontrivial behavior: the ultimate strain gradually increases, whereas the elastic modulus and the yield stress decrease. A correlation of the changes observed in the mechanical characteristics with an increase in the free volume of the material with increasing silica concentration has been established. Atomic-force microscopy has confirmed the existence of a developed system of nanopores with characteristic sizes from 15 to 100 nm in the materials under investigation.     

The state of palladium in the nanosized hydrogenation catalysts modified with elemental phosphorus

The size, nature, and surface state of nanoparticles formed by reduction of Pd(acac)₂ with hydrogen in the presence of P₄ have been elucidated by means of X-ray photoelectron spectroscopy, X-ray powder diffraction analysis, and transmission electron microscopy. The nanoparticles (average diameter of 5.6 nm) consist of Pd₆P and palladium nanoclusters (at initial ratio P/Pd = 0.3). Dimethylammonium dihydro- and hydrophosphates are found in the surface layer of the catalyst nanoparticles. The nanoparticles are stabilized by ammonium salts formed via dimethylformamide hydrolysis.     

Simple reagent for the synthesis of oligonucleotides labeled with 3,3,3′,3′-tetramethyl-2,2′-indodicarbocyanine

Synthesis of a phosphoramidite reagent for the preparation of oligonucleotides labeled at the 5′-end with a fluorescent dye, 3,3,3′,3′-tetramethyl-2,2′-indodicarbocyanine, is described. The efficiency of this reagent is confirmed by the synthesis of several labeled oligonucleotides. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 154–158, January, 2006.     

Self‐Consistent Field Modeling of Three‐Dimensional Morphologies of Branched Lipid Surfactant at Air‐Water Interface

Three‐dimensional mesoscopic morphologies and the thermodynamics of structural phase transitions of amphiphilic lipids at air‐water interfaces are studied using self‐consistent field theory. Changing the relative amount of lipids in the system led to a series of 3D morphologic phases with varying average interfacial area per molecule, mimicking a compression of the model membranes. Membranes of both saturated and unsaturated lipids undergo a transition from cylindrical micelle to lamella when the lipid content in the system increases from 2% to about 19–20%. With further increase in the lipid content, saturated lipids first develop non‐uniform quasi‐2D distributions in the lamella and then gradually transform into a hybrid morphology containing quasi‐planar lamellae. In contrast, unsaturated lipids develop reverse‐micellar morphologies.

     

PII Compounds. Electrical Properties and Structure of Phospha-alkenes and Phospha-azenes

Abstract

Chemistry of twocoordinated phosphorus compounds has been rapidly developed in last years. Parallel with synthesis of new such compounds and investigating of their chemistry research of their spatial and electron structure assumes ever greater importanse. Electrical methods are very informative in this aspect and also permit to determine unknown polaritirs of P^II-bonds, that have great self-dependent interest. We have been studed for the first time the acyclic P^II-compounds containing P=N, P=C, P=P, P=As, P=Sb - double bonds. Phosphaazenes R^IP=NR², where R^I: (Me₃Si)₂N, 2,4,6-^tBu₃C₆H₂; R²: Me₃Si, ^tBu, 2,4,6-^tBu₃C₆H₂ have small polarity 1.5–2.0 D, wich describes by one set of parameteres. The main role in stabilization of -P=N-fragment having E-configuration belongs to sterical factors.     

Polarization of formic acid, acetone, and acetaldehyde

The molar deformation polarizations of formic acid, acetone, and acetaldehyde in the liquid state at 20°C were calculated.