Расчет ядерных тормозных способностей в квазиклассическом приближении

The results of calculating nuclear stopping in the semiclassical approximation for the systems H-Be, H-C, H-W, O-C, O-Be, O-Al are presented. It was found that in the presence of a well in the interatomic interaction potential, an additional maximum appears in the dependence of the nuclear stopping on the energy of the bombarding particles. When using the universal potential without a well, this feature is absent. It is shown that by scaling the data obtained for systems with hydrogen are recalculated for collisions with the participation of hydrogen isotopes D and T. The results obtained are in good agreement with classical calculations, which is explained by the fact that large scattering angles make the main contribution to the nuclear stopping, and the applicability criterion changes to the condition: angular momentum ℓ >> 1.

Моделирование одноосной деформации нанокристаллов магния "жесткой " и "мягкой" ориентировок

Atomistic modeling of high-speed deformation by compression of ideal, defective (5% vacancies, 5% impurity hydrogen atoms) magnesium nanocrystals with "hard" and "soft" orientations at T = 300 – 375 K was carried out. Three interatomic interaction potentials were used. The evolution of the microrelief of the free surface of magnesium nanocrystals in the process of plastic flow is shown. Diagrams "stress σ – deformation ε" are constructed, deformation dependences of the scalar dislocation density are determined, and the strain rate dependences on the degree of deformation ε are constructed. The influence of vacancies and hydrogen atoms on the shape of deformation curves, dislocation structure and scalar dislocation density is shown. Evolution of typical dislocation structures is shown, some typical dislocation reactions are given. Conclusions are drawn on the influence of the type of interatomic interaction potential on the calculated characteristics.

Устойчивость углеродной нанолуковицы в контакте с графитовой подложкой

A theoretical model describing the stability of a carbon nano-onion in the presence of a bulk catalytic graphite phase is constructed based on the continuum approximation of interatomic interaction potential and mechanics of deformed systems. It is shown that a carbon nano-onion becomes unstable when its radius exceeds double value of the radius of a fullerene C_60 molecule.

Термомеханика деформаций в ангармоническом твердом теле

The macroscopic laws determining the temperature and deformations of an anharmonic solid body in a given external temperature force field have been stated in the form of the first thermodynamics law supplemented by equations of state of the body. The internal and free energies necessary for it are found from the statistical sum in which some of degrees of freedom determining the body shape are discharged from statistical averaging. These functions of state have been calculated up to the first order of the perturbation theory in the anharmonicity for the microscopic dynamic model of the body with the interatomic interaction potential energy given as a series in powers of atom coordinates. The classical region of high temperatures is considered.

A Nanoscale Simulation Study of Elastic Properties of Gaspeite

The study of structural and mechanical properties of carbonate rock is an interesting subject in engineering and its different applications. In this paper, the crystal structure of gaspeite (NiCO3) is investigated by carrying out molecular dynamics simulations based on energy minimization technique using an interatomic interaction potential. At first, we focus on the structural properties of gaspeite mineral. And then, the elastic properties are calculated, including the elastic constants, bulk modulus, shear modulus, the S- and P-wave velocities. In the next part of this paper, the pressure effect will be studied on the structural and elastic properties of NiCO3 at high pressure.