Моделирование стеклования тонкого слоя расплава алюминия при сверхбыстром охлаждении в изобарических условиях
It is shown that a sharp increase in viscosity, a change in the decay rate of correlations, and the appearance
of nonequilibrium and transverse sound in a thin film of aluminum melt during rapid cooling occur in the
same temperature range. The analysis is performed using the shear stress autocorrelation functions calculated by the molecular dynamics method. The cooling rate dependences indicate the transition of the
metastable state into the amorphous one rather than a phase transition.
Molecular dynamics study of stress correlations and shear viscosity behavior of the rapidly cooled and re-heated liquid aluminum film is performed. The embedded atom method potential is used at the simulations. The stress correlation behavior is studied in the plane of the film and along the direction normal to the plane. The behavior of the kinematic viscosity and the stress correlationsare compared for cooling and heating process. Using two methods it is shown that the glass transition temperature for the cooling process is higher than for the heating.
Molecular dynamics study of shear viscosity behavior of liquid aluminum is performed. The embedded atom method potential is used at the simulation of isobaric cooling. The viscosity is calculated using the Green–Kubo formula. The stress autocorrelation functions are obtained in the range 300–1200 K. The calculated kinematic viscosity is in agreement with the experimental data for the temperatures above melting temperature. The steep change of the shear viscosity is found below 650 K which we associate with the glass transition and is in a good agreement with the temperature which is obtained using the calorimetric criterion Kolotova et al (2015 J. Non-Cryst. Solids 429 98). The viscosity coefficient can not be calculated using the direct atomistic simulations below that temperature
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.