Beating Homogeneous Nucleation and Tuning Atomic Ordering in Glass-Forming Metals by Nanocalorimetry.

In this paper, the amorphous CeAlCuCo (atom %) alloy was in situ prepared by nanocalorimetry. The high cooling and heating rates accessible with this technique facilitate the suppression of crystallization on cooling and the identification of homogeneous nucleation. Different from the generally accepted notion that metallic glasses form just by avoiding crystallization, the role of nucleation and growth in the crystallization behavior of amorphous alloys is specified, allowing an access to the ideal metallic glass free of nuclei.

Monte Carlo Simulation Used to Calculate Energy Correction Factor for Thermoluminescent Dosimeters Used by Occupational Workers on Pediatric Exams.

The main objective of this work is to simulate the X-ray scattered spectra by different pediatric phantoms (simulation of children subjected to barium meal procedures) to calculate an energy correction factor (ECF) to the reading of thermoluminescent dosimeters (TLDs). To perform this evaluation, the TLDs were positioned over three areas in two occupational workers: eyes, thyroid and hands. The Geant4 toolkit was used to define the spectra collected by TLDs, making possible to calculate the ECF.

Applicability of the Fokker-Planck equation to the description of diffusion effects on nucleation.

The nucleation of islands in a supersaturated solution of surface adatoms is considered taking into account the possibility of diffusion profile formation in the island vicinity. It is shown that the treatment of diffusion-controlled cluster growth in terms of the Fokker-Planck equation is justified only provided certain restrictions are satisfied. First of all, the standard requirement that diffusion profiles of adatoms quickly adjust themselves to the actual island sizes (adiabatic principle) can be realized only for sufficiently high island concentration.

Special Grain Boundaries in Ultrafine-Grained Tungsten.

Field ion microscopy and computer simulation were used for the study of an atomic structure high-angle grain boundary in hard-drawn ultrafine-grained tungsten wire. These boundaries with special misorientations are beyond the scope of the coincident site lattice model. It was demonstrated that the special non-coincident grain boundaries are the plane-matching boundaries, and rigid-body displacements of adjacent nanograins are normal to the <110> misorientation axis.

GEANT 4 simulation of (99)Mo photonuclear production in nanoparticles.

GEANT 4 Monte-Carlo simulation toolkit is used to study the kinematic recoil method of (99)Mo photonuclear production. Simulation for bremsstrahlung photon spectrum with maximum photon energy 30MeV showed that for MoO3 nanoparticle escape fraction decreases from 0.24 to 0.

Discriminating between Light- and Heavy-Tailed Distributions with Limit Theorem.

In this paper we propose an algorithm to distinguish between light- and heavy-tailed probability laws underlying random datasets. The idea of the algorithm, which is visual and easy to implement, is to check whether the underlying law belongs to the domain of attraction of the Gaussian or non-Gaussian stable distribution by examining its rate of convergence. The method allows to discriminate between stable and various non-stable distributions.

Dislocation mechanism of deuterium retention in tungsten under plasma implantation.

We have developed a new theoretical model for deuterium (D) retention in tungsten-based alloys on the basis of its being trapped at dislocations and transported to the surface via the dislocation network with parameters determined by ab initio calculations. The model is used to explain experimentally observed trends of D retention under sub-threshold implantation, which does not produce stable lattice defects to act as traps for D in conventional models. Saturation of D retention with implantation dose and effects due to alloying of tungsten with, e.

The use of nanocomposite coatings with various physicochemical properties in tissue engineering.

We studied the effect of nanocomposite coatings with various physicochemical properties on the structural and functional properties (adhesion potential, phenotype, gene expression) of mesenchymal stem cells. Of all tested nanocoatings (Al2O3, ZrO2, Ta2O5), oxide coating Al2O3 enriched in vitro monolayer bone marrow cell culture with cells carrying mesenchymal stem cells phenotype markers and stimulated expression of ido gene, which can confer new therapeutic potencies to these cells and extend their application in clinical practice.

Thermodynamic approach to the description of dislocation mobility in quasicrystals.

Dislocation mobility in quasicrystals is calculated using basic thermodynamic and hydrodynamic equations. The dependence of the dislocation mobility on viscosity, vacancies and phasons is given. It is shown that the phasonic defects make the major contribution to the inverse mobility of the free segments of dislocations.

Kinetics of formation of a phase with an arbitrary stoichiometric composition in a multicomponent solid solution.

A kinetic theory of nucleation and growth of a evolving phase with a given stoichiometric composition in a multicomponent solid solution is developed. It is assumed naturally that the phase grows as a result of individual atom incorporation into the phase domain in a stoichiometric ratio. As it is shown, for the case of phase formation in a multicomponent system the basic kinetic equations, describing the nucleation-growth process, can be reduced formally to the respective expression derived for nucleation-growth processes in one-component systems.