The influence of the molecular weight of DMC polyethers on the physical-mechanical properties of PU materials based on them

This article describes synthesis of polyurethane (PU) elastomers based on DMC polyethers. The influence of the molecular weight of DMC polyethers on the strength characteristics and mechanical hysteresis of model PU composites based on them is studied. It is shown that, when the molecular weight of DMC polyethers changes in the range of 2000–4000, the strength of PU materials dramatically increases, while a considerable improvement of elastic properties is observed when using polyethers with MW = 8.000 or higher.     

(Mg,Ni)Ga2O4 Solid Solution with a Spinel Structure

Doklady Chemistry - The boundaries of Mg1 – xNixGa2O4 solid solutions (0 ≤ х ≤ 0.5) with a spinel structure synthesized by the gel combustion method,...     

Early Stage of Structural Changes and Molecular Dynamics of Cytochrome C in an Aqueous Solution Caused by the Addition of Methanol

Crystallography Reports - Molecular dynamics simulations of horse heart cytochrome C were performed in an aqueous solution and in a 50 : 50 water–methanol mixture. Three independent 100-ns...     

Spectral changes in stochastic light beams propagating in turbulent ocean

The behavior of the spectral composition of a typical stochastic beam in a turbulent ocean environ is revealed. The analysis is based on the extended Huygens–Fresnel principle and the coherence theory in the space-frequency domain. The optical source is assumed to be of the Gaussian Schell-model type with a single narrow Gaussian spectral line in the visible region. Optical turbulence in the ocean is assumed to be driven by temperature and salinity fluctuations. It is found that the well-known source correlation-induced spectral shift is compensated by turbulence at sufficiently large distances.     

Generalized stokes parameters of random electromagnetic beams

A generalization of the Stokes parameters of a random electromagnetic beam is introduced. Unlike the usual Stokes parameters, which depend on one spatial variable, the generalized Stokes parameters, depend on two spatial variables. They obey precise laws of propagation, both in free space and in any linear medium, whether deterministic or random. With the help of the generalized Stokes parameters, the changes in the ordinary Stokes parameters upon propagation can be determined. Numerical examples of such changes are presented. The generalized Stokes parameters contain information not only about the polarization properties of the beam but also about its coherence properties. We illustrate this fact by expressing the degree of coherence of the electromagnetic beam in terms of one of the generalized Stokes parameters.     

The NUCLEON experiment: The current status

The main purpose of the NUCLEON experiment is direct measurements of the energy spectra of cosmic rays in the range 10¹¹–10¹⁵ eV with the use of the lightweight facility during a prolonged orbital flight. The energy is determined using a technique based on the measurement of the spatial density of secondary particles produced in the initial event of inelastic interaction. The schematic diagram of the NUCLEON facility, the current status of the project, the results of testing the prototype, and plans are presented.     

Scattering-induced changes in the temporal coherence length and the pulse duration of a partially coherent plane-wave pulse

The scattering of a partially coherent plane-wave pulse on a Gaussian-correlated, quasi-homogeneous random medium is investigated. The analytical expressions for the temporal coherence length and the pulse duration of the scattered field are derived. We demonstrate that the scattering-induced changes in the temporal coherence length and the pulse duration may be used to determine the correlation function of the scattering potential of the medium.     

Volume Characteristics of Lithium Salts in Alcohols

The densities of lithium chloride and nitrate in aliphatic alcohols (methanol, ethanol, 1- and 2-propanol, 1- and 2-butanol, and 1- and 2-pentanol) at 298.15 K in the salt concentration range from 0 to 3.5 mol kg^{- 1} were measured by means of vibrational densimeter. The resulting density data were used to calculate the apparent and partial molar volumes of the solvents and solutes.     

Beam wander of J 0- and I 0-Bessel Gaussian beams propagating in turbulent atmosphere

Root mean square (rms) beam wander of J ₀-Bessel Gaussian and I ₀-Bessel Gaussian beams, normalized by the rms beam wander of the fundamental Gaussian beam, is evaluated in atmospheric turbulence. Our formulation is based on the first and the second statistical moments obtained from the Rytov series. It is found that after propagating in atmospheric turbulence, the collimated J ₀-Bessel Gaussian and the I ₀-Bessel Gaussian beams have smaller rms beam wander than that of the Gaussian beam, regardless of the choice of Bessel width parameter. However, the extent of such an advantage depends on the chosen width parameter, Gaussian source size, propagation distance and the wavelength. Focusing at finite distances of the considered beams causes the rms beam wander to decrease sharply at the propagation distances equal to the focusing parameter.