Study of the phase behavior of a diblock copolymer in an ionic liquid: Outlook for use of the integral-equation theory

It is shown that the integral-equation theory may be used to study the phase behavior of a diblock copolymer in an ionic liquid with allowance made for the solvent structure. Features of microphase separation are exemplified via calculation of the mean-field spinodal temperature and order-disorder transition temperature as functions of the copolymer concentration at two different lengths of the cationic tail of the ionic liquid. The need to allow for the solvent structure during construction of the theory of the phase behavior of block copolymers in ionic liquids is substantiated.     

The influence of the planar potential form on the channeling radiation spectrum

Energies for transitions between bound states for planar-channeled electrons are calculated. The continuum planar potential constructed from atomic ones in Molier and Hartree-Fock-Slater approximation are used. It is shown that the H-F-S line energies calculations are in a good agreement with the experimental data for diamond.     

Energy loss of light ions in metals

On the basis of dielectric formalism the analytical expressions for the calculation of close collision and plasmon excitation contributions to the total energy loss of light ions (protons, α-particles) on valence electrons of metals have been obtained. The importance of accounting for the relation between the mentioned contributions while interpreting the results on ion dechannelling due to their multiple scattering on the crystal valence electrons has been pointed out. The ratio of the total energy loss for the best channelled light ions to the energy loss in the non- oriented target in the energy range of E ≈ 100 keV-500 MeV has been calculated.     

Speed of sound in the gaseous refrigerant R-409A

Speed of sound in the gaseous refrigerant R-409A has been measured by ultrasonic interferometer in the temperature range from 293 to 373 K and at pressures from 0.05 to 0.58 MPa. The experimental uncertainties of the temperature, pressure, and speed of sound measurements were estimated to be within 20 mK, 4 kPa, and 0.1–0.2 %, respectively. On the basis of the obtained data, the isobaric molar heat capacity was calculated for the ideal-gas state. A comparison of the obtained results with the calculated speed of sound on the basis of REFPROP program was carried out.     

Femtosecond Laser Irradiation of a Multilayer Metal–Metal Nanostructure

JETP Letters - The selective modification of upper layers of a Ni/Al multilayer nanostructure irradiated by a single femtosecond laser pulse has been studied. The analysis of surface topography...     

Interchain exchange in the anionic polymerization of hydroxyalkyl (meth) acrylates

The kinetics of chain propagation and interchain exchange reactions in the anionic polymerization of 2-hydroxyethyl acrylate initiated by lithium tert-butylate were compared. The kinetic parameters of the reactions under consideration were determined. An abnormal ratio between the activation energies of chain propagation and interchain exchange was revealed and explained by the involvement of hydroxyl groups in changes of reactivities of double bonds and ester groups of the initial monomer, the resulting polymer, and the growing active centers of polymerization. The effect of self-inhibition of polymerization was observed and attributed to the fact that ethylene glycol and its alkoxy alcoholate occurring as H-bonded cyclic complexes form at the beginning of the reaction.     

Epoxy-amine composites with ultralow concentrations of single-layer carbon nanotubes

The physical and mechanical properties of composite materials based on epoxy-amine systems—diglycidyl ether of diphenylolpropane-eutectic mixture of aromatic amines (40 wt % m-phenylenediamine-60 wt % 4,4′-diaminodiphenylmethane) and epoxy-diane resin ED-20-eutectic mixture of aromatic diamines with ultralow contents (≤0.1 wt %) of single-layer carbon nanotubes—are studied. It is shown that, for the concentration dependence of the modulus of elasticity during tension, the additivity rule is obeyed only at the lowest concentrations of carbon nanotubes. In this case, the presence of near-surface layers of a matrix with an increased elastic modulus should be considered.     

Consecutive recovery of uranium oxides from uranyl-containing molten alkali metal sulfate electrolytes

The oxygen coefficient (atomic ratio O/U) of a cathode product and the cathode current yield in consecutive recovery of uranium oxides from molten salt mixtures (nLi₂SO₄ + (1 ? n)Cs₂SO₄) + UO₂SO₄ and (Li,Na,K)₂SO₄ + UO₂SO₄ in air were analyzed as dependent on the electrolyte and the mean solvent-salt cation radius. The increasing mean solvent-salt cation radius and decreasing UO₂SO₄ concentration in the electrolyte during long-term electrolysis suppress the solvolysis of uranyl ions and decrease the oxygen coefficient in the cathode product. The cathode current yield decreases systematically during electrolysis and drops to zero long before the uranium is completely recovered from the melt. The ultimate uranium recovery increases as the mean solvent-salt cation radius increases.