107 Works

Formation of ordered ZnO structures grown by the ALD method on hybrid SiC/Si (100) substrates

S.A. Kukushkin, A.V. Osipov, I.A. Kasatkin, V.Y. Mikhailovskii & A.I. Romanychev
Crystalline structure and composition of the ZnO films grown by atomic layer deposition (ALD) on the n- and p-type Si (100) substrates with a SiC buffer layer were studied. The SiC buffer layers have been synthesized by a novel method of atomic substitution (partial chemical replacement) of Si atoms by carbon atoms in the subsurface layer of the Si substrate. A four-component epitaxial texture of ZnO in a direction close to [101] on the n-...

The time-step boundary-element scheme on the nodes of the Lobatto method in problems of 3-D dynamic poroelasticity

L.A. Igumnov, A.N. Petrov & I.V. Vorobtsov
A boundary-element scheme for analyzing initial boundary-value problems of 3-D porelasticity is considered. The scheme is based on a time-step method of numerically inverting Laplace transform. According to the method, a solution in time is calculated using quadrature formulas, based on complex values of the function in specific points. The choice of the points is determined by Lobatto method being one of Runge-Kutta methods. A possibility of using two- and three-stage Lobatto methods is considered....

Preparation and physico-chemical properties of gracilaria/PVA/GA/CNT-based hydrogel for slow/controlled release material

H. Hendrawan, F. Khoerunnisa, F.I. Ekawati & Y. Sonjaya
In this study, we synthesized a hydrogel from the extract of gracillaria (GR), poly-(vinyl alcohol) (PVA), glutaraldehyde (GA), and carbon nanotube (CNT). To confirm the synthesis of hydrogel, several characterizations were done, including fourier transform infra red (FTIR) and scanning electron microscope (SEM). Analysis on the material performance under various parameters (such as swelling ratio and release behavior of potassium from hydrogel into aqueous media) was also carefully evaluated based on weight measurement and flame-photometry...

DENSIFICATION RATE INFLUENCE ON NANOPOWDER COMPACTIBILITY

G.Sh. Boltachev, E.A. Chingina, A.V. Spirin & N.B. Volkov
The paper concerns processes of high-speed compaction of nanosized powders. The processes of uniform and uniaxial compaction have been simulated by the granular dynamics method. Nanoparticles interaction, in addition to known contact laws, includes dispersive attraction, formation of a strong interparticle bonding as well as the forces caused by viscous stresses in the contact region. For different densification rates, the densification curves (pressure vs. density) have been calculated. Relaxation of the stresses after the compression...

Coupled thermo-electro-mechanical modeling of thermal fatigue of single-crystal corset samples

A.V. Savikovskii, A.S. Semenov & L.B. Getsov
The possibilities of predicting thermal fatigue durability for single crystal on the base of coupled thermo-electro-mechanical finite-element modeling with using of deformational criterion and microstructural models of inelastic deformation are investigated. Results of thermal and stress-strain state simulations of single-crystal corset specimens under cyclic electric heating and cooling are presented and discussed. Comparison of computational results with experimental data for various single-crystal nickel-based superalloys demonstrates a good accuracy in the prediction of the number of...

Study of heat dissipating material using boron nitride fabricated by laser ablation

Atsushi Yamaguchi, Pankaj Koinkar & Akihiro Furube
More research interest is developing rapidly on two dimensional (2D) materials owing to their excellent electro-optic properties to develop next generation of electronics and highly functional devices. Among well-known and widely used 2D materials, boron nitride (BN) is an electrical insulator with a band gap of 5.5 eV, and attests high chemical stability, outstanding mechanical properties, and high thermal conductivity. Accordingly, BN is considered as a promising candidate to improve the heat dissipation material performance....

Model for the formation of GaAs-Au axial nanowire heterostructures under flash lamp annealing

Vladimir G. Dubrovskii
Semiconductor-metal nanowire heterostructures have attracted a particular interest over the last decade. However, they often suffer from low interface and crystalline quality. Here, we present a model for the formation of GaAs-Au axial nanowire heterostructures from GaAs/Au core-shell nanowires encapsulated into SiO2 under flash lamp annealing, as described in the previous work. The model reveals the basic mechanism and establishes the main control parameters of the process which enable high quality GaAs-Au heterostructures. It can...

Modeling plastic deformation and damage accumulation processes in structural steels under block non-symmetric low-cycle loading

Ivan A. Volkov, Leonid A. Igumnov & Denis N. Shishulin
To assess the reliability and the scope of applicability of the defining relations of mechanics of damaged media (MDM), plastic deformation and damage accumulation processes in a number of structural steels under low-cycle loading have been numerically investigated, and the obtained numerical results have been compared with the data from fullscale experiments. It is shown that the introduced MDM model qualitatively and quantitatively describes the main effects of plastic deformation and damage accumulation processes in...

Applied element method in the solution of plane problems in the theory of creep

A.S. Chepurnenko, A.A. Savchenko & V.S. Chepurnenko
The article deals with the consideration of creep in the solution of plane problems by the applied element method. The derivation of the resolving equations is given, as well as the solution of the test problem for the cantilever beam. For calculations, the authors developed a program in the Matlab software package.

Interatomic potentials for describing impurity atoms of light elements in fcc metals

G.M. Poletaev, I.V. Zorya, R.Y. Rakitin & M.A. Iliina
Parameters of Morse potentials for describing the interactions of atoms of light elements C, N, O with atoms of fcc metals Al, Ag, Ni are found. This set of three metals is unique in that two of them have almost the same radii of atoms, while the other two have almost identical electronegativities. The search for potential parameters was carried out according to the empirical relationships observed for a large number of metals having C,...

Analysis of seismic waves excited in near-surface soils by means of the electromagnetic pulse source \"Yenisei\"

V.M. Sadovskii, O.V. Sadovskaya & E.A. Efimov
The northern territories of Eastern Siberia are characterized by a permafrost-taiga structure of the surface layer of soil, which reduces the efficiency of geological exploration using seismic sources of explosive and vibratory types. Therefore, Geotech Holding Company developed a special eco-friendly electromagnetic pulse source "Yenisei", which seismic waves are the subject of analysis using high-performance computing in this paper. Computational technology, worked out previously for solving the problems of the dynamics of viscoelastic, elastic-plastic, granular...

Analysis of the dynamic behavior of sand-lime and ceramic bricks

D.A. Lamzin, A.M. Bragov, A.K. Lomunov, A.Yu. Konstantinov & F. dell'Isola
The results of dynamic tests on building brick samples were analyzed using the incubation time fracture criterion. The strength and time properties of sand-lime brick and ceramic brick were under study. The tests were carried out using the classical Kolsky method and its modification - dynamic splitting. Strain rates under compression reached 2.5·103 MPa/s while stress rates under tension reached 3.5·102 GPa/s. It is noted that the strain rate affects the strength and time properties...

Use of advanced materials in protection against high-velocity impact and explosion

Aleksander V. Gerasimov, Leonid A. Igumnov & Anatoliy M. Bragov
Numerical studies of the behavior of combined barriers consisting of solid and porous materials were carried out during high-speed impact on them with thin plates. It is shown that the introduction of plates of porous materials into the composition of combined barriers can significantly reduce the amplitude of compression waves and reduce the likelihood of spall damage. Comparison of the results of numerical modeling of high-speed impact interaction processes with the experimental results of other...

On wave field formation on the surface of piezoactive bodies with inhomogeneous coating

I.E. Andzhikovich, T.I. Belyankova, V.V. Kalinchuk, G.Yu. Levi, M.O. Levi & V.A. Lyzhov
Within the framework of a model for the piezoelectric structure with a coating made of a functionally graded material with a piecewise-continuous variation of properties, the problem of propagation of horizontally polarized shear surface waves was investigated. The influence of the polarization vector orientation and the nature of the coating inhomogeneity on the propagation of surface waves in an "acoustically homogeneous" structure was studied.

The strengthening and the electrical resistivity of thermo-mechanical deformation processed Cu-Nb composite wires

P.A. Lukyanov, M.V. Polikarpova, N.E. Khlebova, V.V. Guryev, N.A. Belyakov & V.I. Pantsyrny
The effects of deformation and heat treatment on the electrical resistivity and the tensile strength of nanostructured Cu/Cu-18%Nb composite wires are studied. The correlated behavior of electrical resistivity and strength depending on the mode of thermo-mechanical processing is ascertained. The main mechanism of strengthening and increasing the electrical conductivity, associated with the reduction in the size of the structure, is considered. A good agreement is shown between the average distances between the Nb filament measured...

Prediction of radiation shielding properties of self adhesive elastic coating

Vasiliy Cherkasov, Valeriy Avdonin, Yuriy Yurkin & Dmitrii Suntsov
Analytical definition of radiation shielding properties of polymeric materials is proposed. This method shows good convergence of theoretical calculations with experiment. Obtained results show, that to receive material with high protective properties it is necessary to add barite or tungsten filler in the amount of 50-70 % of the volume into the composition. Carried out researches show, that at energy of irradiation 59 keV materials with thickness of 2-3 mm are sufficient for radiation protection....

Effect of anodic voltage on parameters of porous alumina formed in sulfuric acid electrolytes

X. Huang, W. Su, L. Sun, J. Liu, D.A. Sasinovich, O.V. Kupreeva, D.A. Tsirkunov, G.G. Rabatuev & S.K. Lazarouk
Local porous aluminum anodizing with a photolithography mask has been carried out at anodic voltages varying from 15 to 200 V in sulfuric acid electrolytes. Record anodic voltages at room temperature have been achieved leading to new parameters of porous alumina such as interpore distance up to 320 nm, forming cell factor up to 1.2 nm/V, thickness expansion factor up to 3.5, porosity up to 1%, sulfur concentration up to 7.7 at.%. A central angle...

Effect of cooling rate on the crystallization of aluminum alloys under pressure

Maksim S. Denisov
The influence of pressure on the compressibility of liquid metal and the release of latent crystallization heat is studied. It is found that the pressure application combined with the cooling rate creates metastable structures. It can be used for improvement the properties of metals and alloys. doi: 10.18720/MPM.4112019_14

Added mass study of plane structures at their various motions

Daniil Morozov, Dmitry Indeitsev & Alexander Michailov
Using FE analysis, this work fully devoted to added masses determination of the plate in infinite liquid in the case of different movements. Various forms and sizes of the plate are considered. The problem consists of two parts: first is studying of the plate motion in liquid as rigid; second is studying of the plate vibrations in its own modes, fixed with a hard screen and contacting with liquid by one side. The condition observance...

Electron tunneling to the surface states at photocatalysis

T.N. Sidorova & Alexander L. Danilyuk
Simulation of tunneling electrons excited by the sunlight in TiO2 to surface states is performed for TiO2/Si nanostructure. The tunneling transmission coefficient of the surface states created by organic compounds was calculated by phase function method. Dependence of the transmission coefficient of tunneling electrons on potential barrier parameters is explained by interference of transmitted and reflected waves. doi: 10.18720/MPM.4112019_3

The influence of an adhesive layer on the interaction between a piezo-actuator and an elastic 3D-layer and on the excited wave fields

E.V. Kirillova, W. Seemann & M.S. Shevtsova
Piezoceramic transducers are extensively used in nondestructive testing (NDT), structural health monitoring (SHM) and condition monitoring (CM) of various mechanical systems including wind turbines, aircraft structures, bridges and pipeline systems. Piezoelectric transducers are surface bonded on the host structure and are excited to produce structural responses. This article highlights the effect of the adhesive layer between the studied structure and the transducer on the contact characteristics and the structural wave fields. The research also focuses...

On some features of identification of inhomogeneous prestressed state of thermoelastic hollow cylinder with coating

A.O. Vatulyan & S.A. Nesterov
An inverse thermoelasticity problem of identification of inhomogeneous prestressed state of an infinitely long hollow cylinder with a coating is formulated. The characteristics of cylinder's material are described by piecewise continuous functions. A direct thermoelasticity problem is solved on the basis of the shooting method and inversion of solutions based on the Durbin method after applying the Laplace transform. The nonlinear inverse problem is solved by constructing an iterative process, at each stage of which...

BULK GREEN'S FUNCTIONS IN ONE-DIMENSIONAL UNSTEADY PROBLEMS OF ELASTIC DIFFUSION

L.A. Igumnov, D.V. Tarlakovskii & A.V. Zemskov
We consider a one-dimensional unsteady problem of elasticity with diffusion and preset unsteady volumetric disturbances. The mathematical model is based on a local equilibrium model of elastic diffusion. The solution is sought in integral form. The bulk Green's functions are found via Laplace transform and Fourier transform for unbounded medium, sine and cosine transform for semi-bounded medium, Fourier's series for bounded medium.

BORON AND NITROGEN DOPANT ATOMS PRECISE TUNING (INCREMENT AND REDUCTION) OF CHARGE-TRANSFER RATES IN HYDROGENATED GRAPHENE

G.K. Sunnardianto, F. Triawan, A.M. Aamer, S. Hastuty, A.B.D. Nandiyanto & A.G. Abdullah
Graphene is a new remarkable material for diverse applications, especially when grapheme is interacted with hydrogen. The charge-transfer rates (CTR) from hydrogen to graphene is substantial to determine the electronic properties. A new approach to increase and decreases the charge-transfer from hydrogen to graphene is proposed. By using density functional theory calculation method, the effect of B and N doping on the CTR of hydrogenated graphene is investigated. The results found that both of dopants...

APPLIED THEORY FOR ELECTRO-ELASTIC PLATES WITH NON-HOMOGENEOUS POLARIZATION

A.N. Soloviev, V.A. Chebanenko, P.A. Oganesyan, Shih-Fong Chao & Y.-M. Liu
Non-uniformly polarized piezoceramic materials can be used in effective energy harvesting devices. Axisymmetric and plane models of electric elastic bodies were studied using applied theory and finite element method (FEM). Applied theory for devices made of parts with longitudinal and transverse polarization was developed. It was based on bending of electric elastic plates models. Numerical experiments for FEM models were performed in ACELAN package. Applied theory of second order vibrations was introduced.

Registration Year

  • 2019
    107

Resource Types

  • Text
    107

Affiliations

  • Peter the Great St. Petersburg Polytechnic University
    10
  • N. I. Lobachevsky State University of Nizhny Novgorod
    8
  • Institute of Problems of Mechanical Engineering
    8
  • ITMO University
    5
  • Ioffe Institute
    4
  • Bauman Moscow State Technical University
    3
  • //ror.org/02x91aj62:Peter the Great St. Petersburg Polytechnic University
    3
  • Tver State Technical University
    2
  • Kuban State University
    2
  • Saint Petersburg State University
    2