Papers by Keyword: Surface Diffusion

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Authors: Howatchinou Tossoukpe, François Valdivieso, Julien Bruchon, Sylvain Drapier
Abstract: This paper presents a level set framework for the modelling of doping effect during surfacediffusion phenomena in a granular packing. The molecular flux of the doped compound is related tothe chemical potentials of all the diffusion species. The evolution of the grain compact is simulatedin three dimensions, based on the resulting kinetic law relating the surface diffusion velocity to thethermodynamic driving force. An anisotropic adaptive mesh, based on the level set function propertiesis used to refine the mesh in the surroundings of the grain surface. The simulations have been perfomedby using parallel computing strategy.
Authors: Jun Jie Shen, Kenichi Ikeda, Satoshi Hata, Hideharu Nakashima
Abstract: The creep deformation in pure aluminum was investigated using helicoid spring samples at room temperature, 298 K, and σ < 1.19 MPa. It was found that the stress exponent is n = 0, which means the creep behavior in this region is independent on applied stress but some physical properties of materials. The creep behavior was suggested to be controlled by surface diffusion based on the strongly effect of surface area on creep behavior only in this creep region (n = 0). The threshold creep rate, , called intrinsic deformation limit, decided by surface diffusion was suggested. This discovery provided a new perspective to understand the extremely slow deformation in the nature.
Authors: Duo Zhang, Lin Zhang
Abstract: The geometry structure and adsorption energy of Cu cluster adsorbed on Au (010) surface were affected by both the height of adsorption site and temperature. The height of adsorption site has major impact on the geometry structure and adsorption energy of the cluster when the temperature is low; while it has minor impact on the geometry structure and adsorption energy of the cluster at higher temperature. The adsorption energy is relevant to the atom number of the first layer on the surface vector of the clusters.The structural of Cu clusters on Au surface and its diffusion properties were studied in this paper by molecular dynamics simulation method and computer graphics techniques. The interaction potential between atoms is adopted by EAM form proposed by Johnson, simulation adopted by canonical ensemble of molecular dynamics method, and computer simulation was adopted to simulate the atomic structure of copper clusters of different amounts of atomic layers at different temperature during heating process. Moreover the analysis of the distribution function and the mean square displacement curve were performed by two representativ kinds of copper clusters Cu55, Cu201.
Authors: Simon P.A. Gill, Paul E. Spencer
Abstract: A kinetic Monte Carlo (KMC) model for surface diffusion on a 2D lattice is proposed. An equivalent continuum cellular automaton (CA) model is derived from this. These models are shown to produce similar results at high temperatures. A hybrid KMC-CA model is derived which consistently allows material to transfer between a deterministic CA model and a stochastic KMC model concurrently embedded within it. The quality of the model is demonstrated by simulating the flattening of a sinusoidal surface profile and the evolution of an elliptical body into a circular one.
Authors: Alexander Tarasenko, Lubomir Jastrabik, F. Nieto, C. Uebing
Authors: Andriy Gusak, A.O. Kovalchuk, King Ning Tu
Abstract: Recently) the point contact reactions between silicon nanowires (covered by natural oxide) and nanowires or nanodots of metals (nickel, cobalt, platinum) were discovered and studied. These reactions have at least three remarkable characteristics: (1) the reaction product phase is quite different from thin film or bulk reactions (for example, in Ni-Si reaction the appearing phase is Ni1Si1 or Ni1Si2, depending on the orientation of Si, instead of common Ni2Si phase); (2) Phase is formed not in the contact zone but, instead, near the wire tip or between two point contacts; (3) Subsequent phase growth of silicide inside silicon nanowire is a “stop-and-go” process consisting of waiting time before formation of critical island of each new atomic layer and then the fast filling of this new layer (mechanism suggested in 30-s for ideal crystals) Models of surface diffusion along and penetration through silicon oxide are presented. Nucleation models need more place and will be discussed in subsequent parts
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