A fractal model of reinforcement of elastoplastic nanocomposites

Within the framework of fractal analysis and percolation theory, an alternative model of reinforcement of filled polymers is offered. Practically, this model can be used only to describe the reinforcement of nanocomposites, because, according to the treatment considered, a pronounced reinforcement can be reached only at ratios of filler particle diameter to the statistical segment length of about 10 and less. A theoretical calculation showed a good qualitative and quantitative agreement with experiments. The type of reinforcement mechanism of composites is determined by the type of the space (fractal or Euclidean) in which the structure of the polymeric matrix is formed. __________ Translated from Mekhanika Kompozitnykh Materialov, Vol. 42, No. 6, pp. 797–802, November–Decem ber, 2006.     

Spectral and kinetic characteristics of the pulsed cathodoluminescence of a natural IIa-type diamond

Emission spectra and decay kinetics of pulsed cathodoluminescence of a natural IIa-type diamond sample are investigated in the spectral range 340–680 nm. The luminescence of the vibronic N3-system and band A are observed. The N3-system is dominant on a nanosecond scale and has a 415.2-nm zero-phonon line with phonon replicas in the range 430–460 nm. The decay time for the N3 system is found to be 30–50 ns. Structureless band A is observed on a millisecond scale; it has a maximum at 460 nm and a decay time of 8.5–8.8 ms. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 53–57, January, 2007.     

Kinetics of formation of a linear polymer-polymer network system in the presence of 3d metal chelates

For semi-interpenetrating polymer networks (semi-IPNs) based on an incompatible polyurethane network/linear polymethylmethacrylate pair formed in situ in the presence of 3d metal chelates, we have studied the effect of the system composition on the kinetics of formation of the components and the nature of complex formation between the metal compound and the polymer matrix. The ratio of the system components has been shown to have an effect on the selection of the macroligand in formation of complexes of the metal chelate with the polar groups of the semi-IPN, where the general character of the kinetic behavior for the formation of the network and the linear polymer is preserved. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 6, pp. 351–356, November–December, 2006.     

Phototransformations of Phenols in Aqueous Solutions under Different Excitation Modes

The photolysis of aqueous solutions of two widespread environmental organic ecotoxicants—phenol and 4-chlorophenol—on excitation by UV radiation from a KrCl exciplex laser and a glow-discharge KrCl excilplex lamp was studied. The irradiated solutions were studied by spectroscopic techniques. The laser and lamp photolyses were compared.     

On the pomeranchuk singularity in asymptotically free theories

We calculate the high-energy amplitude in the spontaneously broken Yang-Mills model within the leading logarithmic approximation, and find out that the vector meson is reggeised whereas the Pomeranchon is a fixed branch point located at the right hand from j = 1. The asymptotic freedom alters the situation in this model significally.     

Modeling of the short-range order for polymers by the ideal peak method

The method of the modeling of the radial distribution function for liquid and amorphous polymers is described. The method consists in the use of pair functions of the radial distribution (ideal peaks) for the construction of the distribution function of intramolecular distances and the comparison of the theoretical function with the experimental one. The theoretical functions for two possible conformations of the poly(tetramethylene glycol) macromolecule were computed. It follows from comparison of the computed theoretical functions with the experimental one that the intramolecular distances do not become apparent in the experimental curve. The differential functions containing the contributions of the intermolecular distances only were obtained by subtraction of the theoretical function from the experimental. Comparison of the differential functions of the two conformational states which were taken as models proved that there are large numbers of gauche conformations in the liquid polymer in contrast to the crystalline polymer. On the basis of the analysis of the differential functions for liquid and crystalline poly(tetramethylene glycol), we concluded that the short-range order of the polymer is distorted during the melting in that the basic plane of the poly(tetramethylene glycol) paracrystal becomes almost hexagonal.     

Production of heavy quarks on protons within the semihard QCD approach

The inclusive production of heavy quarks in p\(\bar p\) interactions at the Tevatron and LHC energies is considered within the semihard QCD approach. The dependence of the total and differential cross sections for the production of b quarks and B mesons (and of muons originating from the subsequent semileptonic decay B → μν _μ X) on various samples of unintegrated gluon distributions is studied. The results obtained by calculating azimuthal correlations between the transverse momenta of final particles are presented. The theoretical results are compared with the latest experimental data obtained by the D0 and CDF Collaborations at the Tevatron.