Synthesis and modification of low-molecular-weight polybutadiene and polystyrene for use as adhesive additive to asphalt

Russian Journal of Applied Chemistry - Low-molecular-weight butadiene and styrene polymers with narrow molecular-weight distribution were prepared by the mechanism of living polymerization with...     

Features of the Crystal Structure of the Polyimide Derived from 3,3'-Diaminobenzophenone and 3,3',4,4'-Benzophenonetetracarboxylic Dianhydride

Changes occurring in the structural organization of the thermoplastic polyimide derived from 3,3'-diaminobenzophenone and 3,3',4,4'-benzophenonetetracarboxylic dianhydride on heat treatment at temperatures in the range 250-350°C were studied, and the influence of these changes on the rheological behavior of the polymer was examined.     

Energy Characteristics of the Parametric Generator Based on a Nonlinear ZnGeP2 Crystal Intended for Lidar Systems and Remote Gas Analysis

Russian Physics Journal -     

(Pyrrol-1-yl)furazans

Short-time reactions of 3-amino-4-R-furazans with 2,5-dimethoxytetrahydrofuran in boiling acetic acid afford (pyrrol-1-yl)furazans. One of the products was characterized by X-ray diffraction analysis.     

Method of following changes in spectra

Journal of Applied Spectroscopy -     

The exclusive reaction of pion quasi-elastic knockout from nucleon <Emphasis Type="Italic">p(e,e′ π)B</Emphasis> to various states of the final baryon-spectator <Emphasis Type="Italic">B</Emphasis> and the quark models for the pion cloud of nucleon

The pion momentum distributions (MDs) in four channels of virtual decay p→B+π, B = N, Δ, N _1/2-(1535), N _1/2+(1440) are calculated in two models, the microscopic model of ³ P ₀ scalar q−q fluctuation with the pion as a composite q−q-system and the chiral semi-microscopic model of πq interaction with the pion as a structureless Goldstone boson. The results of the above models are similar for the baryon states B = N, Δ, N _1/2-(1535) but are rather different for the Roper resonance N _1/2+(1440) which corresponds to excitation of two oscillator quanta in the nucleon. The experimental investigation of pion MDs by means of the reaction of quasi-elastic knockout of pion by an electron of a few GeV energy p(e, e′ π)B may be very suitable for Jefferson Laboratory, Virginia (JLab).     

High-contrast dark resonances on the D<Subscript>1</Subscript> line of alkali metals in the field of counterpropagating waves

A new method providing a significant increase in the amplitude and contrast of dark resonances is proposed. The method is based on the use of the σ₊?σ_? configuration of polarized counterpropagating waves, D₁-line excitation in alkali metal atoms, and small-sized cells. Qualitative considerations of the scheme are confirmed by the results of numerical calculations. A variant of a standing wave with homogeneous circular polarization is also discussed.     

Properties of Film Materials Based on Composite Nanofibers from Aliphatic Copolyamide and Carbon Nanotubes for Tissue Engineering

The investigation of the dependence of effective viscosity on shear rate for a water-alcohol solution of an aliphatic copolyamide and its mixtures with single-wall carbon nanotubes reveals that additives of the nanoparticles in the amount of 0.5 wt % lead to a substantial reduction in the effective viscosity as the shear rate rises. The measurement of the surface tension and electrical conductivity of the solutions bearing 0.1–2.0 wt % of the nanotubes allows one to choose an optimal mode for electrospinning of the composite nanofibers based on the aliphatic copolyamide. The introduction of carbon nanofibers reduces the specific resistance of the material to 8.9 × 10⁹ Ω m, but increases the elastic modulus. The lack of cytotoxicity of the resulting materials and the high proliferative activity of human dermal fibroblasts on their surface allow one to use the film materials based on the composite nanofibers in cell technologies and as matrices for tissue engineering.