scholarly journals Размерная зависимость упругих свойств нанокристалла аргона

2019 ◽  
Vol 61 (1) ◽  
pp. 148
Author(s):  
М.Н. Магомедов

AbstractThe state equation ( P ) and isothermal elastic modulus ( B ) are calculated for argon macro- and nanocrystals at T = 10 K using in the framework the RP(vac)-model of nanocrystal. The isochoric and isobaric (at P = 0) dependences of the Debye temperature (Θ), of the first (γ) and second ( q ) Grüneisen parameters, as well as the specific surface energy (σ), B and B '( P ) = (∂ B /∂ P )_ T , are studied as the functions of size and shape of the nanocrystal. As shown, the isothermally isobaric decrease in nanocrystal size is accompanied by a decrease in functions Θ, q , σ, B and B '( P ) and by an increase in the γ parameter. However, the elastic modulus rises in the case of the isothermally isochoric decrease in the nanocrystal size. When the nanocrystal deviates from its most energetically optimal shape (a cube for the RP(vac)-model), the size dependences of these functions become more noticeable.

2020 ◽  
Vol 62 (12) ◽  
pp. 2034
Author(s):  
М.Н. Магомедов

For a disordered fcc-Au-Fe substitution alloy, the parameters of the Mie–Lennard-Jones pairwise interatomic potential are determined. Based on these parameters, the concentration dependencies of lattice properties for the macrocrystal of this alloy are calculated. Calculations of 20 properties of macrocrystals fcc-Au, fcc-Fe and fcc-Au0.5Fe0.5 are showed good agreement with experimental data. Using the RP-model of the nanocrystal, the state equation P(v, T; N) and baric dependences of both lattice and surface properties of the fcc-Au0.5Fe0.5 alloy are calculated. Calculations were performed at temperatures T = 100, 300 and 500 K for both a macrocrystal (N = Macro) and a cubic nanocrystal with N = 306 atoms. It is shown that with an isothermal-isobaric (P = 0) decrease in the size of a nanocrystal, its the Debye temperature, elastic modulus, and specific surface energy decrease, while its the specific volume, thermal expansion coefficient, specific heat capacity, and Poisson's ratio increase. At low temperatures in a certain pressure region, the specific surface energy increases at an isothermal-isobaric decrease in the number of atoms in the nanocrystal. As the temperature increases, this pressure region disappears.


1990 ◽  
Vol 211 ◽  
Author(s):  
S. P Shah ◽  
Z. Li ◽  
B. Mobasher

AbstractThis paper explores the behavior of the interface of glass fiber and cementitious matrix under the effect of aging. Pull-out tests of multiple alkali resistant glass fiber strands embedded in portland cement paste matrix were conducted. Four different curing regimes of 3 and 14 days normal curing, in addition to 3 and 7 days accelerated aging were employed. A recently developed method of characterizing interfacial properties was used to identify and evaluate the important parameters at interface. The experimental data are presented on the parameter of shear stiffness of a fiber-matrix boundary layer, the shear bond strength, the frictional bond strength and the specific surface energy as a function of fiber embedded length. It was observed that aging had a larger effect on the stiffness of the interface, the shear bond strength and the specific surface energy than on the frictional bond.


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