Факультет електроніки та інформаційних технологій (ЕлІТ)
Permanent URI for this communityhttps://devessuir.sumdu.edu.ua/handle/123456789/20
Browse
6 results
Search Results
Item Molecular Dynamics of Tribological Processes at Interaction of Cu and Au Nanoparticles with Graphene Sheet(Sumy State University, 2012) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Prodanov, N.V.; Sinko, D.O.This work has a goal to study the behavior of metal nanoparticles on the graphene layer. After processing obtained data we have studied dependence of friction force on contact area of nanoparticle, in all cases it is linear. This conclusion is confirmed by real experiment results. Dependence of friction force on lateral coordinate of center of mass of nanoparticle has a sawtooth form. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/34849Item Computational investigation of the temperature influence on the cleavage of a graphite surface(2010) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Prodanov, N.V.Mechanical exfoliation of a graphite surface with an adhesive nanoasperity is studied under different temperatures ranging from 298 K to 2 K using classical molecular dynamics. Two types of the interlayer interaction are investigated. For a pairwise Lennard-Jones potential the complete removal of the upper graphene layer during the retraction of the nanoasperity occurs in the whole range of the temperatures considered. The results obtained using registry dependent potential, which takes into account electronic delocalization contribution besides the van der Waals one, exhibit more pronounced temperature dependence. In this case the exfoliation takes place for temperatures higher than 16 K, but beginning from 8 K down to 2 K the system behavior manifests qualitative changes with the absence of cleavage of the sample. Analytical estimates combined with the results of the simulations reveal that the contribution of the overlap of pi orbitals of carbon atoms plays an important role in the exfoliation of graphite. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/18085Item Molecular dynamics of cleavage and flake formation during the interaction of a graphite surface with a rigid nanoasperity(Carbon, 2010) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Prodanov, N.V.Computer experiments concerning interactions between a graphite surface and the rigid pyramidal nanoasperity of a friction force microscope tip when it is brought close to and retracted from the graphitic sample are presented. Covalent atomic bonds in graphene layers are described using a Brenner potential and tip-carbon forces are derived from the Lennard-Jones potential. For interlayer interactions a registry-dependent potential with local normals is used. The behavior of the system is investigated under conditions of different magnitudes of tip-sample interaction and indentation rates. Strong forces between the nanoasperity and carbon atoms facilitate the cleavage of the graphite surface. Exfoliation, i. e. total removal of the upper graphitic layer, is observed when a highly adhesive tip is moved relative to the surface at low rates, while high rates cause the formation of a small flake attached to the tip. The results obtained may be valuable for enhancing our understanding of the superlubricity of graphite. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/18081Item Molecular dynamics of graphene preparation by mechanical exfoliation of a graphite surface(STC "Institute for Single Crystals", 2010) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Prodanov, N.V.Класична молекулярна динаміка використана для дослідження фізичних процесів, які мають місце при наближенні до графітового зразку і відведенні від нього жорсткого адгезивного нановиступу кристалічної поверхні. Розглянуто нановиступи з двома різними сталими решітки. Поведінка системи вивчена в умовах декількох значень величини взаємодії суміжних матеріалів і швидкості руху нановиступу. Визначено енергії взаємодії виступ – зразок, достатні для мікромеханічного розколювання поверхні графіту, у результаті якого утворюється шар графену, прикріплений до нановиступу. При цитуванні документа, використовуйте посилання http://essuir.sumdu.edu.ua/handle/123456789/18079Item Study of friction of Ag and Ni nanoparticles: an atomistic approach(American Chemical Society, 2010) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Prodanov, N.V.Manipulation of metal nanoparticles using atomic force microscope is a promising new technique for probing tribological properties at the nanoscale. In spite of some advancements in experimental investigations, there is no unambiguous theoretical treatment of processes accompanying the movement of metallic nanoislands adsorbed on a flat surface and additional research is required. In this paper, we describe computer experiments based on classical molecular dynamics in which the behavior of silver and nickel nanoparticles interacting with a graphene sheet and sheared with constant force is studied. Frictional force acting on the nanoislands is measured as a function of their size. It is shown that its average value grows approximately linearly with contact area, and slopes of linear fits are close to the experimentally observable ones. The dependence of the friction force value and of the shape of the measured friction curves on the type of metal atom is revealed and its possible reasons originating from atomistic background are discussed. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/16489Item Molecular dynamics simulations of ultrathin water film confined between flat diamond plates(Condensed Matter Physics, 2008) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Prodanov, N.V.Molecular dynamics simulations of ultrathin water film confined between atomically flat rigid diamond plates are described. Films with thickness of one and two molecular diameters are concerned and TIP4P model is used for water molecules. Dynamical and equilibrium characteristics of the system for different values of the external load and shear force are investigated. An increase of the external load causes the transition of the film to a solidlike state. This is manifested in a decrease of the diffusion constant and in the ordering of the liquid molecules into quasidiscrete layers. For two-layer film under high loads, the molecules also become ordered parallel to the surfaces. Time dependencies of the friction force and the changes of its average value with the load are obtained. In general, the behaviour of the studied model is consistent with the experimental results obtained for simple liquids with spherical molecules. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/16211