Papers by Keyword: Statistical Mechanics

Abstract: The problem of crystal damage recovery and of impurity substitution in implanted semiconductors is considered from a statistical mechanical viewpoint. This is done by resorting to a thermodynamic pseudo-potential originally developed for cooperative structural rearrangements in disordered systems close to their glass transition. The dependence of the substitutional fraction φ on the post-implantation annealing temperature T_ann in Al/4H-SiC systems is discussed in the light of these ideas. After completion of the annealing process, an Arrhenius plot of φ(T_ann) shows a slope in the order of 1 eV or less, depending on the amount of lattice damage initially produced by the implantation. Slopes ∼4 eV are found after incomplete annealing, indicating that substitution occurs mainly in damaged crystal cells. These concepts are suggested to be used for optimization of the doping procedure by ion implantation.

Abstract: The improved technology of position control and alignment of the continuous casting machine (CCM) equipment based on high-precision online geodetic measurements is considered. The mathematical model for the technological axis of the continuous casting machine, the technique of the rational alignment of the machine’s equipment and the software implementing this technique are proposed. The application experience of the developed technique for control and aligning the equipment of continuous casting machines of different types is shown. The data on the efficiency of the technique for continuous casting machine equipment and its impact on the quality of a continuously cast ingot are presented.

Abstract: Currently in the process of engineering, but increasingly implemented simulation methods since they are an economical and feasible to predict the behavior of some variable you wish to benefit. The problem of fluid simulation is a broad field of study, traditionally in this area are implemented domain discretization methods, volumes, differences or finite elements (Computational Fluid Dynamics), in this work, a different approach where the discretization is made on the physical properties of fluid and the fluid for reconstruction from its microscopic properties, simulating these, propagating Boltzmann distribution functions for the grid of nodes, this set is comprised of a fluid group of nodes, nodes fluid the border and nodes structure, docked the method to the boundary conditions necessary to simulate Glycerol in a pipe.

Abstract: The paper is mainly about reviewing on static phases of materials as numeric analyzing with its comparison to dynamical phases. All of analyzes are with based on dynamical and static equilibrium and its mode revision. Also, states changing in materials and their physical – chemical transfer changes have been covered by defined properties in this paper. We use some numeric solutions such as Boltzmann method in analyzing states in this paper.

Abstract: The wetting phenomena and adhesion between Ag-Cu-Zr molten alloys (where Zr is an active brazing element) and ZrB2-ceramic substrate have been investigated from theoretical and experimental point of view. The wetting phenomena of molten alloy/ceramic substrate depend on the bonding characteristics of liquid alloys and ceramics as well as the magnitude of interactive forces at the interface. Accordingly, the first step of this investigation is to determine the surface properties of Ag-Cu, Ag-Zr and Cu-Zr liquid alloys. The energetics of the bulk and the surface of liquid alloys have been analysed in the framework of statistical mechanical theory in conjunction with Quasi-Lattice Theory (QLT), through the study of the concentration dependence of various properties such as surface tension, surface composition, concentration fluctuations in the long wavelength limit and Warren-Cowley chemical short-range order parameter. Combining the Young and the Dupré equations, the obtained values of surface tension together with contact angle data have been used to calculate the work of adhesion.

Abstract: A novel statistical mechanics approach to quantify the effects of hot rolling and deformation on the formation of dislocations in a single grain scenario is presented. The dislocations are dealt as equilibrium defects in the crystal structure, which is assumed to be deformed via the formation of dislocations or single atom displacements at the grain boundary, which involve breaking their bonds and are thus termed “bond breaking atoms”. The deformation process is applied to steels of a variety of grain size and dislocations densities. The model has the capacity to describe the grain energy increase as a function of crystallography, grain sizes, temperature and degree of deformation, providing thus an aid in predicting the conditions for dynamic recovery and recrystallization.