Abstract
The dynamics of liquid multiphase systems largely depends on the conditions on the interface. The behavior of a system with adsorbed surfactant layers at the interface boundaries may differ qualitatively from the behavior of a system with pure surface. The experimental study of such systems is difficult, since the presence of adsorbed layer can most often be judged only by indirect signs. Therefore, most of the research is carried out by numerical modeling. Unfortunately, the currently existing numerical studies of liquid multiphase systems with adsorbed surfactant layer are far from perfect due to numerous simplifications and approximations assumed in theoretical models. In this paper, we propose a new approach for visualization and studying the boundary between a clean surface and an adsorbed surfactant layer. It is based on the comparison of track images of the fluid motion in the volume and the registration of the temperature distribution at the interface boundary. This approach made it possible to unambiguously associate the characteristic regions on the temperature profile with the position of the so-called stagnation point. The proposed method for visualizing the stagnation point can be useful in a number of problems of interface hydrodynamics based on the thermocapillary effect.
AbstractThe ab initio calculations of the magnetic anisotropy of thin (to six monolayers) nickel films and iron films with unusual fcc structures formed upon intercalation of graphene with Fe atoms are presented. The data have been obtained for both the pure-surface films and the films coated with graphene. The density functional theory and the pseudopotential method are used to calculate the magnetic moments of atoms of all the layers and to determine the total energies of the structures with different orientations of magnetic moments of iron and nickel atoms with respect to the film surface. A strong influence of graphene on the magnetic properties contacting iron films is demonstrated.
In this work the evolution of the width of a line (groove) traced on the surface of a sample of bi-crystalline ice, by means of a metallic sheet, in a direction almost orthogonal to the grain edge (BG) was studied. To perform the measurements, the sample of ice submerged in ultrapure silicone oil was maintained at -5 ºC to prevent evaporation from occurring and isolate the effect of surface diffusion in this way. Photographs of the groove were periodically taken, approximately for 100 hours, using a camera coupled to an optical microscope. From these images the evolution of the line width was studied. Finally, the
ice self-diffusion coefficient was determined at -5 ºC.
An ab initio study of Co monatomic nanowires (NW) magnetic properties on pure and oxygen reconstructed Cu (210) surface was performed. Strong influence of oxygen surface impurity on MAE in Co nanowire was found. High value of magnetic moment and small energy of magnetic anisotropy (MAE) were obtained in Co nanowires on pure Cu (210) surface. After oxygen reconstruction of Cu (210) surface (Cu (210)-(2×1)O) the significant enhancement of MAE was found in Co nanowires, while the magnetic moment of Co atoms is practically unchanged. Oxygen on Cu (210) surface rotates easy magnetization axis in Co NW with respect to the pure surface.
Studying the surfactant dynamics at non-isothermal liquid surface with thermography