Papers by Keyword: Atoms

Abstract: The analysis of the strength characteristics and electrical conductivity of annealed Cu-1.0wt.%Cr-0.1wt%Zr alloy subjected to subsequent deformation under various conditions was carried out by analytical modeling methods. The contributions of the regions with nanotwins, as well as such defects of the crystal structure as vacancies, alloying atoms, dislocations, and particles of the secondary phase to the strength and electrical conductivity of the material were estimated.

Abstract: By means of the reactive magnetron sputtering method, a series of Nb–Si–N composite films with different Si contents were deposited in an Ar, N2 and SiH4 mixture atmosphere. These films’ chemical composition, phase formation, microstructure and mechanical properties were characterized by the energy dispersive spectroscopy, X-ray diffraction, transmission electron microcopy, atomic force microscopy and nanoindentation. In the Nb–Si–N films, 3 distinct concentration regions have been observed depending on the Si content. Based on the three concentration regions, a three-step model is proposed for the film formation of the Nb–Si–N thin films. This model correlates nanoscale structures with macroscopic properties of the films.

Abstract: Detailed investigations have been carried out [1,2] on the response of microparticles and nanoparticles to lasers of various pulse durations and energies. A first principles model has been developed that allows the prediction of all thermo-mechanical effects that will be generated from any laser pulse, such as pressure generation and phase changes. This theoretical work also predicts the thermo-mechanical effects transmitted to the surrounding transparent medium that the nanoparticles are immersed in, such as water or a solid polymer. The use of short enough pulses produces shock fronts in the surrounding medium. We calculate how short the laser pulse must be as a function of nanoparticles properties. We also show that measurements of pressure peaks in the medium can be used to determine the thermo-mechanical properties of the absorbing nanoparticles, such as bulk modulus and thermal expansion coefficient. Because the measurements can be made in the surrounding medium, they are easier to perform experimentally. Using this approach on particles of decreasing size, measurements of the pressure in the medium allow the determination of the size at which a nanoparticle is small enough to deviate from its bulk behavior and manifest discrete atom, finite size effects. This allows the prediction of how the thermo-mechanical properties of nanoparticles will change as their size decreases.