Materials physics and mechanics

RAR RUS 85-116 Peter the Great St. Petersburg Polytechnic University Melker A.I.

St.Petersburg, Russia

Structure of Condensed Solid Matter In this contribution we have considered the main items of the history of ideas on the structure of condensed solid matter. They are divided into two principal groups; one is based on discreteness (numbers, atoms), the other on continuity (geometrical figures). The evolution of these ideas has led to such notion as crystals, long-range and short-range order, continuous and discrete space, quasicrystals, types of disorder, amorphous structure. In its turn the new notions generated new theories, such as group theory, topology, etc. Significant attention was given to molecular dynamics, a new powerful instrument for solution of many problems connected with the structure of disordered phases. Leaning on a molecular dynamics, we have developed the theory of deformation and fracture for amorphous materials. crystals; long-range and short-range order; continuous and discrete space; quasicrystals; types of disorder; amorphous structure; molecular dynamics; disordered phases; deformation and fracture of amorphous materials https://mpm.spbstu.ru/article/2012.21.1/ MPM_2012_13_2_P01.pdf

RAR RUS 117-123 Peter the Great St. Petersburg Polytechnic University Sanin

St.Petersburg, Russia

Bagmanov Waves in Quantum Systems with Nonlinearity and Walls The nonlinear cubic Shrödinger equation is integrated numerically for quantum systems confined by potential walls of a well. If nonlinear potential describing nonlinearity is distributed on the whole width of the well, soliton generation is possible. For the nonlinear potential distributed on the right half of the well with free motion on the left one the propagation of waves occurs. Solutions for the probability density, expectation positions and velocities of the wave were analyzed under different initial conditions including the Gaussian and specified wave packets. the nonlinear cubic Shrödinger equation soliton https://mpm.spbstu.ru/article/2012.21.2/ MPM_2012_13_2_P02.pdf

RAR RUS 124-129 Belarusian State University of Informatics and Radioelectronics Kozlova

Minsk, Belarus

Belarusian State University of Informatics and Radioelectronics Lyskouski

Minsk, Belarus

Belarusian State University of Informatics and Radioelectronics Nelayev

Minsk, Belarus

Electronic Properties of Ternary Compounds with Vacancy Clusters: ab initio Simulation Electronic and magnetic properties of ternary crystal TlMeX2 compound (TlGaS2 as an example) with alone vacancy or their clusters were studied by means of first-principle (ab initio) approximation. It was shown that presence of S-vacancy clusters narrows the band gap of TlGaS2 crystal significantly while Tl - vacancy clusters increase it slightly. Restructuring TlGaS2 crystal due to vacancy or vacancy clusters presence leads to manifestation of ferromagnetic properties of the compound with the spin polarization value approx. 22 % when the number of vacancies in the cluster increases up to extremely high values. Revealed phenomena may be used in the censoring applications. ab initio simulation electronic properties spin; anisotropy TlMeX2 compounds sensory https://mpm.spbstu.ru/article/2012.21.3/ MPM_2012_13_2_P03.pdf

RAR RUS 130-142 National Research Nuclear University Savatorova

Moscow, Russia

National Research Nuclear University Talonov

Moscow, Russia

Institute of Applied Mechanics Russian Academy of Sciences Vlasov

Moscow, Russia

Institute of Applied Mechanics Russian Academy of Sciences Volkov-Bogorodsky

Moscow, Russia

Multi Scale Modeling of Thermoelastic Properties of Composites with Periodic Structure of Heterogeneities The majority of processes in composite materials involve a wide range of scales. Because of the scale disparity in multi scale problem, it's often impossible to resolve the effect of small scales directly. In this paper we perform multi scale modeling in order to analyze properties of composite materials with periodical structure under temperature and stresses influence. We consider a homogeneous matrix with periodic system of spherical particles separated from the matrix by an interphase. Each component has its own thermodynamic and mechanical (elastic) properties. We replace differential equations with rapidly varying coefficients by homogenized equations having effective parameters, which incorporate multi scale structure and properties of any component. We study, how effective properties of the system "matrix-interphase-inclusion" can depend on sizes of inclusions, thickness of interphase, mechanical and thermodynamic properties of components of a composite material. multi scale modeling; thermoelastisity; effective thermo mechanical properties; nano composite materials; elastomeric composites https://mpm.spbstu.ru/article/2012.21.4/ MPM_2012_13_2_P04.pdf

RAR RUS 143-146 St. Petersburg State University Prozorova

St.Petersburg, Russia

Dispersion and the Equations of Mechanics This work is devoted to studying the influence of angular momentum variation in an elementary volume and cross flux on its sides on some equations of continuum mechanics. The self- diffusion effect is investigated for fluctuations of shock waves for the Mach number M≈1. As another example, a beam and a plate are considered. angular momentum; conservation laws; nonsymmetrical stress tensor; Boltzmann equation; Chapman-Enskog method; the Navie-Stokes equation https://mpm.spbstu.ru/article/2012.21.5/ MPM_2012_13_2_P05.pdf

RAR RUS 147-156 Peter the Great St. Petersburg Polytechnic University Igolkin

St.Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Melker A.I.

St.Petersburg, Russia

Molecular Hydrodynamics of Underwater Explosion In this contribution we report on modeling underwater explosion in the framework of molecular dynamics. We have developed a computer program which allows studying the underwater explosion in two dimensional Lennard - Jones liquid. Calculations of the dynamical structure of underwater explosion displayed the striking resemblance of the underwater-explosion evolution obtained and the real process; namely, generation of a shock wave and its expanding; formation of a cavity; disintegrating the shock wave, when reaching a surface, into two parts which begin to move in opposite direction parallel to the surface; transforming the cavity into a water crater of an arising water volcano; its activity and decay. underwater explosion; molecular dynamics; two dimensional Lennard - Jones liquid; dynamical structure; generation of a shock wave; formation of a cavity; water crater https://mpm.spbstu.ru/article/2012.21.6/ MPM_2012_13_2_P06.pdf

RAR RUS 157-161 Peter the Great St. Petersburg Polytechnic University Burkov

St.Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Melker A.I.

St.Petersburg, Russia

Molecular Hydrodynamics of Tsunami Waves We have developed a molecular dynamic approach for studying tsunami generation. In a two-dimensional model developed a force, which models the generation of disturbance, was incorporated into the water after reaching thermodynamic equilibrium. The temporal evolution of an arising wave shows that at first the disturbance creates the wave of large amplitude which propagates with a significant velocity and a cavity at the site of disturbance. When the wave reaches shallow water, the amplitude and velocity decreases, and the wave changes its shape that is consistent with observations for areas with a large angle of bank. As the bank is approached, the wave density decreases, and foam formation takes place. From the very beginning the surface layer has a lesser density, as if one has "rarefied" water. During the wave propagation the rarefied water penetrates deeper. molecular dynamic; tsunami generation; two-dimensional model; temporal evolution; large amplitude wave; cavity; bank; foam formation; rarefied water https://mpm.spbstu.ru/article/2012.21.7/ MPM_2012_13_2_P07.pdf

RAR RUS 162-174 Peter the Great St. Petersburg Polytechnic University Bezrukova

St.Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Vlasova

St.Petersburg, Russia

Optical Characterization of 3D Disperse Systems with Nano- and Micro- Particles: Polymodality of Size Distributions Natural (including biomedical) 3D disperse systems (DS) with nano- and/or microparticles are inherently polycomponent polymodal polydisperse systems. Characterization of such systems by different compatible non-destructive optical methods (refractometry, absorbance, fluorescence, light scattering: integral and differential, static and dynamic, unpolarized and polarized) is desirable because of feasibility to organize the on-line testing of their state. At this road it is necessary to take into account peculiarities of inverse optical problem solution for such complex systems (so called “three ill”: "ill-defined" 3D DS, "illposed" problems, "ill-conditioned" systems of equations). At the information–statistical approach to the optical characterization and control of 3D DS it is possible to go round these peculiarities and to qualify the 3D DS state changes. biomedical and mineral particles; 3D disperse systems; inverse problem; light scattering; mixtures of nano- and micro- particles; on-line control; optical methods; polymodal size distributions https://mpm.spbstu.ru/article/2012.21.8/ MPM_2012_13_2_P08.pdf

RAR RUS 175-180 Aalto University Rackauskas

Finland

Aalto University Talka

Finland

Aalto University Kauppinen

St.Petersburg, Russia

Aalto University Nasibulin

Finland

Zinc Oxide Tetrapod Synthesis and Application for UV Sensors Zinc oxide tetrapods (ZnO-Ts) were synthesized by air oxidation of zinc vapor. For stable production of the ZnO-Ts at the furnace temperatures of 900 °C, the lowest evaporator temperature was found to be 480 °C. Aerosol measurements showed that the fraction of naturally charged particles decreased with evaporator temperature from 89 % at 480 o C to 43 % at 420 o C. Various UV sensors were prepared to study the response and reset times and the On/Off ratio as a function of the ZnO-T concentrations, interelectrode distance and air humidity conditions. The presence of humid air was found to increase the conductivity of the ZnO-T sensors and to lower the response and reset times as well as On/Off ratio to 98, 96 and 88 %, respectively. ZnO; tetrapod; synthesis; UV sensor https://mpm.spbstu.ru/article/2012.21.9/ MPM_2012_13_2_P09(1).pdf

RAR RUS 181-185 Peter the Great St. Petersburg Polytechnic University Gerasimov

St.Petersburg, Russia

St.Petersburg State Technological Institute Matuzenko

St.Petersburg, Russia

St.Petersburg State Technological Institute Proskurina

St.Petersburg, Russia

Purity Analysis of Trade Produced C-60 Fullerene The article compares the product purity of fullerene C-60, synthesized in different laboratories. The content of main product impurities was determined by liquid chromatography, infrared spectroscopy and mass spectrometry. It is shown that only one method of chromatographic analysis, the results of which are given in the certificates of goods, is not enough for detecting detect impurities. fullerene C-60 product purity https://mpm.spbstu.ru/article/2012.21.10/ MPM_2012_13_2_P10.pdf