East European Journal of Physics

Cosmological Dynamics of Anisotropic Kaniadakis Holographic Dark Energy Model in Brans-Dicke Gravity

A. Vijaya Prasanthi — 2024-06-01

The present study examines the Kaniadakis holographic dark energy in the context of the Brans-Dicke scalar-tensor theory of gravity (Phys. Rev. 124: 925, 1961). This paper focuses on a background with an anisotropic Kantowski-Sachs space-time that is homogeneous in space. Under these circumstances, the Brans-Dicke scalar field denoted as ϕ is used as a function of the average scale factor a(t). Using a graphical model to analyze the model's physical behaviour is part of the inquiry into the Universe's accelerating expansion. We evaluate the cosmological parameters such as the scalar field, the equation of state parameter and the deceleration parameter. Furthermore, the models' stability is assessed through the application of the squared sound speed (ν²_S). For our models, we derive the widely accepted cosmic planes such as ω_kde-ω'_kde and statefinder (r,s) planes. It is found that the scalar field is a decreasing function of cosmic time and hence the corresponding kinetic energy increases. The deceleration parameter exhibits accelerated expansion of the universe. It is mentioned here that the equation of state parameter lies in the phantom region and finally attains the ΛCDM model. Also, the ω_kde-ω'_kde plane provides freezing and thawing regions. In addition, the statefinder plane also corresponds to the ΛCDM model. Finally, it is remarked that all the above constraints of the cosmological parameters show consistency with Planck observational data.

Behaviour of Quark and Strange Quark Matter for Higher Dimensional Bianchi Type -I Universe in f(R,T) Gravity

S. Thakre — 2024-06-01

This research paper delves into a thorough examination of the behaviour exhibited by higher dimensional Bianchi Type-I universes, incorporating the presence of quark and strange quark matter within the framework of f(R,T) gravity. The solutions derived for the field equations encompass both exponential volumetric expansion and power law scenarios. Under the exponential expansion model, both the pressure (p_q) and energy density (p_q) associated with quark matter are initially finite at the inception of cosmic time, gradually diminishing to zero as time progresses towards infinity. Conversely, within the power law model, these parameters start off infinitely large at t = 0, subsequently decreasing to zero as time approaches infinity. Furthermore, an exploration of the physical and geometrical attributes of the model is conducted. Notably, in power law expansion models, the behaviour of strange quark matter mirrors that of quark matter concerning pressure (p) and energy density (ρ). But in exponential expansion model quark pressure and strange quark pressure behave differently. The bag constant emerges as a critical factor influencing the universe's expansion, with observations revealing that both pressure and energy density tend towards the bag constant at large time scales (t→∞). Specifically, the pressure p→ -B_C and the energy density ρ→ B_C as time approach infinity. The negative pressure sign denotes the universe's expansion during later epochs.

Analysis of Marder’s Space-Time Tsallis Holographic Dark Energy Cosmological Model in f(R, T) Theory of Gravity

Abhijeet Ompratap Dhore — 2024-06-01

In this paper, the investigation explores an anisotropic cosmological model based on Marder’s space-time Tsallis holographic dark energy (THDE) within the framework of f(R, T) theory of gravity, where R represents the Ricci scalar and T signifies the trace of the stress energy-momentum tensor. field equation have solved for class of f(R, T) gravity i.e. f(R, T) = R + f(T). To obtain the precise solution, we employed the density of the THDE model along with the volumetric expansion laws, namely the power law and exponential law. Also explores the physical and geometrical aspects of the model.

Anisotropic Barrow Holographic Dark Energy Models in Scalar-Tensor Theory of Gravitation

Y. Sobhanbabu — 2024-05-18

In this research, we have derived the solution of the field equations of the scalar-tensor theory of gravitation, proposed by Saez and Ballester(Phys. Lett. A113, 467:1986) within the frame-work of Bianchi type-III Universe. We have analyzed the interacting and non-interacting anisotropic Barrow Holographic Dark Energy (BHDE) models by assuming the time dependent deceleration parameter q(t). Further, we have discussed the several cosmological parameters such as energy densities of pressureless dark matter and BHDE, skewness, deceleration, equation of state parameters, ω_BH-ω'_BH plane and stability of the both interacting and non-interacting models. Also, we have observed that in our non-interacting and interacting models deceleration and equation of state parameters support the recent observational data.

Numerical Approach to Burgers’ Equation in Dusty Plasmas With Dust Charge Variation

Harekrishna Deka — 2024-06-01

In this paper, the Crank-Nicholson method is applied to solve the one-dimensional nonlinear Burgers’ equation in warm, dusty plasmas with dust charge variation. After obtaining numerical results, a thorough analysis is conducted and compared against analytical solutions. On the basis of the comparison, it is evident that the numerical results obtained from the analysis are in good agreement with the analytical solution. The error between the analytical and numerical solutions of the Burgers’ equation is calculated by two error norms, namely L₂ and L_∞. A Von-Neumann stability analysis is performed on the present method, and it is found to be unconditionally stable according to the Von-Neumann analysis.

Existence of Small Amplitude KDV and MKDV Solitons in a Magnetized Dusty Plasma with q−Nonextensive Distributed Electrons

Muktarul Rahman — 2024-06-01

The existence and propagating characteristics of small amplitude dust-ion-acoustic (DIA) Korteweg-de Vries (KdV) and modified KdV solitons in a three component magnetized plasma composed of positive inertial ions with pressure variation, noninertial electrons and negative charged immobile dust grains are theoretically and numerically investigated when the electrons obey a q-nonextensive velocity distribution. Utilizing the reductive perturbation method, to derive KdV and modified KdV equations and obtain the DIA soliton solutions along with the corresponding small amplitude potentials. This study shows that there are compressive and/or rarefactive solitons and no soliton at all, due to the parametric dependency on the first-order nonlinear coefficient through the number density of positive ions and negative dust grains and the electron nonextensivity. The coexistence of compressive and rarefactive solitons appears by raising the measure of nonlinearity coefficient to the second-order using the modified KdV equation. The properties such as speed, amplitude, width etc. of the propagating soliton are numerically discussed.

Reflectionless Incidence of the p-Polarized Electromagnetic Wave Through Solid-State Structure “Coating-Uniaxial Plasmonic Metasurface-Dielectric-Metal”

Mykola Biletskiy — 2024-06-01

In this work we studied the effects which occur during the incidence of p-polarized electromagnetic wave on the solid-state structure “coating-uniaxial plasmonic metasurface-dielectric-metal”. The purpose of this work is researching how the coating influences the effect of reflectionless incidence of the p-polarized electromagnetic waves on the solid-state structure “uniaxial plasmonic metasurface-dielectric-metal”. Numerical modelling was used to find the conditions that lead to reflectionless incidence of the p-polarized electromagnetic wave on the solid-state structure under consideration. Using this method we determined the parameters of the coating which are required to observe incidence of p-polarized waves with no reflection. It was found that dielectric coating of the solid state structure significantly changes the behavior of the effect. We showed that dielectric permittivity of the coating changes the frequencies at which reflectionless p-polarized waves occur. The dependency was established between permittivity and thickness of the coating which causes the effect of the reflectionless incidence of p-polarized waves. The conducted research has a great scientific and practical interest. The solid-state structure that was studied can be applied for designing conceptually new types of nanoelectronic and optical devices.

A Simplistic Analytical Model for Hydrogen Surface Coverage Under the Influence of Various Surface-Related Processes and Ion Bombardment

Ivan I. Okseniuk — 2024-06-01

The paper describes a simple analytical model that allows the calculation of hydrogen surface coverage under the influence of several processes that can co-occur during the ion-beam bombardment/sputter analysis of a sample surface, in particular during analysis by secondary ion mass spectrometry (SIMS). The model considers processes of dissociative adsorption, desorption, absorption from the surface into the sample volume, and removal by ion bombardment. After describing the model, we provide some examples of its practical applications for interpretation of the experimental results obtained during in situ SIMS studies of hydrogen interaction with the hydrogen-storage alloys TiFe, Zr₂Fe, and with nickel. In the examples, some quantitative characteristics of surface-related processes involving hydrogen, such as hydrogen sputtering rate, activation energy of hydrogen desorption and absorption, have been successfully determined using various model approaches.

Transition Probabilities, Oscillator and Line Strengths in Sc XIX

Zaheer Uddin — 2024-06-01

Scandium XIX ion is a member of the isoelectronic sequence of Li-like ions. Numerical coulomb approximation and quantum defect theory have been used to calculate energies, quantum defects & transition probabilities, oscillator, and line strengths of Sc XIX ion for the transitions ns → mp, np → ms, np → md, and nd → mp Rydberg series. The energies of Sc XIXX ions up to n = 5 are given in the NIST database and the literature. We used quantum defect theory and determined the energies and quantum defects up to n = 30. The energies and quantum defects of 125 levels are reported for the first time. Sc XIX ion's transition probabilities, oscillator, and line strengths were compared with the corresponding values in the NIST database of spectral lines. The NIST database contains data of only seventy-six spectral lines. Only six spectra lines have percent uncertainties of more than 10%. The results of the remaining seventy spectral lines agree well with the NIST values. Almost 1800 transition probabilities, oscillators, and line strengths are new.

Evolution of Vector Vortex Beams Formed by a Terahertz Laser Metal Resonator

Andrey V. Degtyarev — 2024-05-05

Analytical expressions for the nonparaxial mode diffraction of a terahertz laser metal waveguide resonator are obtained. The study assumes interaction between the modes and a spiral phase plate, considering different topological charges (n). Also, using numerical modeling, the physical features of the emerging vortex beams as they propagate in free space are studied. The Rayleigh-Sommerfeld vector theory is employed to investigate the propagation of vortex laser beams in the Fresnel zone, excited by the modes of a metal waveguide quasi-optical resonator upon incidence on a spiral phase plate. In free space, the spiral phase plate for exciting TE₁₁ mode from the profile with the intensity maximum in the center (n = 0) forms an asymmetric ring one with two maxima (n = 1, 2). For the exciting TE₀₁ mode, the initial ring (n = 0) structure of the field intensity is transformed into a structure with a maximum radiation intensity in the center (n = 1), and later again into a ring (n = 2). The phase front of the beam for the E_y component of the linearly polarized along the y axis TE₁₁ mode changes from spherical to spiral with one on-axis singularity point. In the phase profile of the transverse components of the azimuthally polarized TE₀₁ mode, a region with two and three off-axis phase singularity points appears.

Mathematical Modeling of Uranium Neutron-Producing Target of Subcritical Assembly NSC KIPT

V.V. Gann — 2024-06-01

This work is devoted to calculating the rate of radiation damage production in a uranium target irradiated with high-energy electrons with an energy of 100 MeV. The Monte Carlo program MCNPX was used to perform a complete mathematical modeling of a complex of processes occurring in a uranium target when irradiated with high-energy electrons: the development of an electromagnetic shower, the production of photoneutrons, the transport of particles in the target and the creation of radiation damage in it. The analysis showed that fragments of U-238 photo-fission give the main input into the rate of damage production in a uranium target which reaches the value of 100 dpa/year. The expected service life of a uranium target under irradiation is 3 years of operation at full accelerator power.

Two-Dimensional Hydrodynamics as a Class of Special Hamiltonian Systems

Kostyantyn M. Kulyk — 2024-06-01

The paper defines a class of Hamiltonian systems whose phase flows are exact solutions of the two-dimensional hydrodynamics of an incompressible fluid. The properties of this class are considered. An example of a Lagrangian one-dimensional system is given, which after the transition to the Hamiltonian formalism leads to an unsteady flow, that is, to an exact solution of two-dimensional hydrodynamics. The connection between these formalisms is discussed and the Lagrangians that give rise to Lagrangian hydrodynamics are introduced. The obtained results make it possible to obtain accurate solutions, such as phase flows of special Hamiltonian systems.

Free Convective MHD Radioactive Flow Across a Vertical Plate Enclosed in a Porous Medium Taking into Account Viscous-Dissipation, Thermo-Diffusion and Chemical-Reaction

Salma Akhtar — 2024-06-01

The paper examines solution for a two-dimensional steady, viscous, heat dissipation, incompressible hydro-magnetic free convective flow past a uniformly moving vertical porous plate immersed in a porous material in the presence of the Soret effect, Dofour effect and Chemical reaction. A constant magnetic field is directed into the fluid area perpendicular to the plate. The MATLAB built-in bvp4c solver approach is used to solve the governing non-dimensional equations. The discussion of the current issue focuses mostly on the impacts of thermal diffusion, magnetic field, thermal radiation, Grashof number, Soret number, Dufour number, and chemical reaction. It is observed that the Soret number improves fluid temperature. In addition, the fluid's temperature, concentration, and velocity all drop as the magnetic field parameter rises. Although the heat dissipation caused by the medium's porosity is usually disregarded in convective MHD flow simulations, it is considered in this work.

Oscillatory Maxwell-Cattaneo Ferroconvection in a Densely Packed Rotating Porous Medium Saturated with a Viscoelastic Magnetic Fluid

Naseer Ahmed — 2024-06-01

The combined effect of second sound and the viscoelasticity is examined using the classical stability analysis on the onset of rotating porous medium ferroconvection. Local thermal equilibrium is assumed between the solid matrix and fluid. Present problem is examined by an analytical approach by considering the pertinent boundary conditions. Normal mode analysis technique is utilized for obtaining the critical values for both instabilities namely stationary and oscillatory. We noticed that the oscillatory mode of instability is favored over the stationary mode of instability. We found that magnetic forces, second sound, nonlinearity in magnetization, Vadasz number, stress relaxation due to viscoelasticity and Taylor-Darcy number are in favour of advancing oscillatory porous medium ferroconvection whereas strain retardation postpone the outset of oscillatory porous medium ferroconvection. Convection cell size effects by different parameters and the oscillation’s frequency are also noted. This problem shall have significant feasible technological applications wherein viscoelastic magnetic fluids are involved.

Thermal and Mass Stratification Effects on MHD Flow Past an Accelerated Vertical Plate with Variable Temperature and Exponential Mass Diffusion Embedded in a Porous Medium

Digbash Sahu — 2024-06-01

This study looks at how the impacts of thermal and mass stratification on magnetohydrodynamic (MHD) flow alongside a vertically accelerating plate featuring variable temperature and exponential mass diffusion within a porous medium. The Laplace transform technique is utilized to solve the governing equations related to flow, energy, and mass diffusion. Subsequently, the impact of stratification on the flow field, temperature, and mass diffusion is examined. The study indicates that thermal and mass stratification significantly affects the profiles of velocity, temperature, and mass diffusion. Additionally, it has been discovered that a stable state for the velocity is achieved as both stratification parameters are raised, whereas stable states for the temperature and concentration occur when mass stratification is heightened but thermal stratification is reduced.

Modelling and Simulating the Heat Transference in Casson EMHD Fluid Motion Exacerbated by A Flat Plate with Radiant Heat and Ohmic Heating

Bamdeb Dey — 2024-06-01

The current study presents the results of a numerical investigation of thermal radiation's consequences, ohmic heating, and electromagnetic hydrodynamic drag on the Casson fluid flow across a flat surface. By incorporating suitable similarity parameters, the equations that regulate the system are converted into non-linear ordinary differential equations. The MATLAB Bvp4c algorithm is used for computing nonlinear ODEs numerically. To optimize the industrial and ecological processing, it is crucial to study the flow of Casson fluids (including drilling muds, fossilised coatings, different sedimentation, and specific lubricating petroleum products, polyethylene dissolves, and a range of colloids) in the presence of heat transmission. Graphics and tables have been employed to present computational findings for various spans of the tangible variables that dictate the velocity and temperature distributions. The fluid rate decreases when the magnetic and Casson parameters rise, whereas fluid velocity increases as the local electric parameters grow. This exemplifies the intricate relationship between electromagnetic radiation and fluid mechanics. Growing Eckert number, thermal radiation, specific heat, and Biot number boost temperature profiles, whereas growing Casson parameter and local electric parameters diminish them, showing diverse impacts on heat transmission phenomena. Additionally, this inquiry pertains to the coefficient of skin friction and Nusselt values were covered. New experimental studies will benefit from this theoretical work, nevertheless.

Thermal and Mass Stratification Effects on Unsteady MHD Parabolic Flow Past an Infinite Vertical Plate with Variable Temperature and Mass Diffusion Through Porous Medium

Pappu Das — 2024-06-01

This study examines how thermal and mass stratification affect unsteady MHD parabolic flow past an infinite vertical plate through porous medium with variable heat and mass diffusion. Analytical solutions are derived for unitary Prandtl and Schmidt numbers using Laplace transform technique to simulate the the flow's physical process. The investigation takes into account how the flow field is impacted by thermal and mass stratification. Following that, the outcomes of the stratification case are then comapared with the scenario in which the flow field has no stratification. The finding of this study can help us comprehend more about the unsteady MHD parabolic flow and provide insightful information for stratified systems.

Numerical Analysis of Entropy Generation of MHD Casson Fluid Flow Through an Inclined Plate with Soret Effect

Parismita Phukan — 2024-06-01

In this present study, entropy generation for an unsteady MHD Casson fluid flow through an oscillating inclined plate is investigated. Here, along with reaction by chemical and thermal radiation incorporation of Soret effect is also analysed. The solution of the equation which governs the flow problem are obtained by finite difference method (FDM). The features of flow velocity, concentration and temperature are analyzed by designing graphs and their physical behaviour is reviewed in details to study the impact of different parameters on the fluid problem. The skin friction, the rate of heat and mass transfer of the fluid problem also has significant impact under the influence of the parameters. The results indicate that Soret effect and other parameters has considerable impact on an unsteady MHD casson fluid and on the total entropy due to heat transfer and flow friction.

Thermo-Diffusion and Diffusion-Thermo Effects on MHD Convective Flow Past an Impulsively Started Vertical Plate Embedded in Porous Medium

Kangkan Choudhury — 2024-06-01

This study introduces an analytical solution for the unsteady MHD free convection and mass transfer flow past a vertical plate embedded in porous medium, taking into account the Soret and Dufour effects. Initially, the perturbation method is employed to decouple the equations resulting from the coupling of the Soret and Dufour effects. Subsequently, the Laplace Transform Technique is applied to solve the governing equations. The expressions for velocity, temperature, concentration, skin-friction, Nusselt, and Sherwood numbers are derived. The effects of the main parameters are discussed, revealing that an increase in the Soret number leads to a decrease in temperature while increasing velocity and concentration. Similarly, the Dufour parameter causes an increase in temperature and velocity, while concentration decreases. However, the effect of the Dufour and Soret parameters on velocity does not show a significant difference.

Thermal Stratification and Chemical Reaction Effects on MHD Flow Through Oscillatory Vertical Plate in a Porous Medium with Temperature Variation and Exponential Mass Diffusion

Digbash Sahu — 2024-06-01

This research paper investigates the thermal stratification and chemical reaction effects on MHD Flow through oscillatory vertical plate in a porous medium with temperature variation and exponential mass diffusion. Through the application of the Laplace transform method, the paper derives analytical solutions that precisely depict the physical dynamics of the flow. The investigation utilizes sophisticated mathematical models to scrutinize the complex dynamics between Magnetohydrodynamics (MHD) and convective movements, considering a range of conditions involving temperature fluctuations and exponential rates of mass diffusion. A pivotal finding from this research is the detailed comparison between the outcomes of thermal stratification and those observed in environments lacking such stratification. It is observed that the implementation of stratification within the flow leads to a more rapid achievement of equilibrium or steady-state conditions.

Comparative Analysis of the Plane Couette Flow of Couple Stress Fluid Under the Influence of Magnetohydrodynamics

Muhammad Farooq — 2024-06-01

The present study aims to perform a comparative analysis of the plane Couette flow of a couple stress fluid under the influence of magnetohydrodynamics (MHD) using two different methods: the Optimal Auxiliary Function Method (OAFM) and the Homotopy Perturbation Method (HPM). The couple stress fluid is known for its non-Newtonian behavior, where the fluid's response to shear is influenced by the presence of internal microstructure. The OAFM and HPM are utlized to solve the governing equations of the couple stress fluid flow under MHD. The OAFM is a numerical technique that involves introducing an auxiliary function to simplify the equations, leading to an easier solution procedure. On the other hand, HPM is an analytical method that employs a series solution . The comparative analysis focuses on examining the accuracy, efficiency, and convergence behavior of the two methods. Various flow parameters such as the couple stress parameter, the magnetic parameter, and the velocity ratio are considered to investigate their influence on the flow behavior. Furthermore the HPM solution was compared with the OAFM solution using different graphs and tables. It reveals that the solution obtained by HPM is batter than OAFM solution.

Heat and Mass Transport Aspects of Nanofluid Flow towards a Vertical Flat Surface influenced by Electrified Nanoparticles and Electric Reynolds Number

Aditya Kumar Pati — 2024-06-01

This study examines the heat and mass transfer aspects of the natural convective flow of a nanofluid along a vertical flat surface, incorporating electrified nanoparticles and electric Reynolds number. While conventional nanofluid models like Buongiorno’s model overlook the nanoparticle electrification and electric Reynolds number mechanisms, this study addresses the nanoparticle electrification and electric Reynolds number mechanisms by justifying its relevance, particularly when tribo-electrification results from Brownian motion. This incorporation of the electric Reynold number and nanoparticle electrification mechanism is a unique aspect of this investigation. Using the similarity method and nondimensionalization, the governing partial differential equations of the flow are transformed into a set of locally similar equations. MATLAB's bvp4c solver is employed to solve this set of equations, along with the boundary conditions. The obtained results are validated by comparison with those from previously published works. Graphical representations are provided for the numerical outcomes of non-dimensional velocity, concentration and temperature concerning the nanoparticle electrification parameter and electric Reynolds number. The combined effects of the nanoparticle electrification parameter and the electric Reynolds number on non-dimensional heat and mass transfer coefficients are examined in tabular form. Furthermore, the impact of the nanoparticle electrification parameter on both heat and mass transfer for varying values of the Brownian motion parameter is explored graphically. The primary finding of this investigation indicates that the electrification mechanism of nanoparticles quickens the transfer of heat and mass from a flat surface to nanofluid, suggesting promising prospects for utilization in cooling systems and biomedical applications.

MHD Flow Past a Stretching Porous Surface under the Action of Internal Heat Source, Mass Transfer, Viscous and Joules Dissipation

Sourave Jyoti Borborah — 2024-06-01

The paper investigates two-dimensional, steady, nonlinear laminar boundary layer heat and mass transfer MHD flow past a stretching porous surface embedded in a porous medium under the action of internal heat generation with the consideration of viscous and joules heat dissipation in the presence of a transverse magnetic field. The two-dimensional governing equations are solved by using MATLAB built in bvp4c solver technique for different values of physical parameters. The numerical values of various flow parameters such as velocity, temperature, concentration are calculated numerically and analysed graphically for various values of the non-dimensional physical parameters of the problem followed by conclusions. The study concludes opposite behaviour of transverse and longitudinal velocity under the action of suction velocity in addition to the effects of heat source on fluid velocities, temperature and concentration.

New Trend of Automobile Aspects on MHD of Hybrid Nanofluid Flow Over a Porous Stretching Cylinder: A Numerical Study

Ramasekhar Gunisetty — 2024-06-01

Heat transfer innovation is essential in modern society because thermal management systems need effective heating and cooling processes. It is also an essential component in the vehicle industry and other types of transportation, in addition to automobile industry, aviation technology, the computer industry, and the manufacturing industry. By the inspiration of importance of magnetohydrodynamic hybrid nanofluid over a stretching cylinder with the influence of Williamson fluid and porous medium is examined in this current study. To convert the PDEs into ODEs, suitable self-similarity transformation is used. After applying transformations, for graphical purpose we have used the bvp5c technique. The impact of active parameters affecting the fluid’s capacity to transfer significance is demonstrate in graphs and tables. In the result section we noticed on the velocity outlines decreased for increasing M parameter. The Cf and Nu increased for larger values of the M and curvature parameters. Additional properties of M and Rd parameter inputs result in improved temperature profiles.

Computer Simulation of Adsorption of C60 Fullerene Molecule on Reconstructed Si(100) Surface

Ikrom Z. Urolov — 2024-06-01

The adsorption of the C₆₀ fullerene molecule has been studied in various configurations on a reconstructed Si(100) silicon surface. Among fullerenes, fullerene C₆₀ is of particular importance since it has the most stable form and consists of 60 carbon atoms. Monocrystalline silicon has the diamond structure, the size of its crystal lattice is 5.43 Å. The MD-simulation calculations have been performed using the open source LAMMPS MD-simulator software package and the Nanotube Modeler computer program. The Tersoff interatomic potential has been used to determine the interactions between the Si-Si, C-C and Si-C atoms. The adsorption energy of the C₆₀ molecule on the reconstructed Si(100) surface, the bond lengths and the number of bonds formed depend on the adsorption geometry, i.e. at what point on the substrate the molecule is adsorbed and in what configuration.

Strength Properties pf 25CrMoV Steel Modified by Complex Ion Plasma Treatment with Deposition of Interlayer Metal Coatings

Yuriy A. Zadneprovskiy — 2024-06-01

To improve erosion resistance, strength, and other protective properties, a comprehensive modification of the surface layers of 25CrMoV steel, which is widely used in turbine construction, was performed. For comparative studies, modifications with different interlayer materials (Mo and Ti) and modifications without interlayer were used. The Mo and Ti layers were deposited on a nitrided ion plasma surface. The outer protective layer for all modifications was unchanged and consisted of a Mo2N coating. To determine the role of the deposition of interlayer metal coatings on the strength properties of the complex modified coatings, the distributions of hardness (H, GPa), Young's modulus (E, GPa), and other strength parameters (H/E and H3/E2) measured by cross sections (h, µm) were investigated. The hardness of the Mo₂N coating was ~30 GPa, and the hardness of the nitrided layer was ~12 GPa. The modulus of elasticity for the Mo₂N coating was ⁓415 GPa, and for the nitrided steel - ⁓270 GPa. It was found that the main factor influencing the strength properties of a multilayer structure is related to the different materials of the metal layers. For the Mo and Ti layers, the values of E differ significantly (⁓ 340 GPa and ⁓ 180 GPa, respectively), with almost identical values of H (⁓ 6.5 GPa). The distributions of elastic modulus E = f(h) measured in the modified layers correlate well with the distributions of nitrogen concentration C_N = f(h). The distributions of H/E = f(h) and H³/E² = f(h) for the modifications with Mo and Ti layers show a decrease in mechanical properties in the areas of the intermediate layers (Mo and Ti). For the modification without interlayer, the distributions of these indicators do not show such a drawback. The cavitation resistance of the comprehensively modified 25CrMoV steel is up to 2 times higher than that of the steel in the original condition. NSC KIPT performed extensive ion plasma modification on a pilot batch of turbine parts. These products, which are part of the steam distribution mechanisms, were manufactured by Ukrainian Power Machines JSC (Kharkiv) for the thermal power industry.

Analysis of Kinetic Properties and Tunnel-Coupled States in Asymmetrical Multilayer Semiconductor Structures

Rustam Y. Rasulov — 2024-06-01

This study investigates the kinetic properties of both symmetrical and asymmetrical multilayer and nano-sized semiconductor structures. We develop a theoretical framework using various models and mathematical methods to solve the Schrödinger matrix equation for a system of electrons, taking into account the Bastard condition, which considers the difference in the effective masses of current carriers in adjacent layers. We analyze tunnel-coupled electronic states in quantum wells separated by a narrow tunnel-transparent potential barrier. Our findings provide insights into the electronic properties of semiconductor structures, which are crucial for applications in micro- or nanoelectronics and other areas of solid-state physics.

Research of the Impact of Silicon Doping with Holmium on its Structure and Properties Using Raman Scattering Spectroscopy Methods

Sharifa B. Utamuradova — 2024-06-01

Each crystal structure has its own phonon modes, which appear in the Raman spectrum of Raman scattering. In the case of silicon, phonon modes associated with the diamond structure of silicon can be detected. In a Raman spectrum, the position of the lines, their intensity, and the width of the lines are usually measured. Raman spectroscopy is a powerful tool for studying crystalline materials at the molecular level, and its application in the study of semiconductors and nanomaterials provides important information about their structure and properties. In this study, the spectra of two types of silicon were analyzed: n-Si and p-Si, as well as their doped analogues n-Si<Ho> and p-Si<Ho>. The obtained Raman imaging results demonstrated spatially varying nanocrystallinity and microcrystallinity of the samples. The n-Si<Ho> and p-Si<Ho> spectra indicate the appearance of a Raman band at 525 cm^-1 with a shift of -5 cm^-1 and +5 cm^-1, respectively, relative to the position of the silicon substrate peak, indicating the presence of tensile strain in the materials. The absence of other impurity peaks indicates the high purity of the n-Si<Ho> and p-Si<Ho> samples. The holmium doped Si material exhibits additional peaks in the Raman spectra, which is attributed to the presence of vacancies and defects in the newly formed Si-Ho compositions. The results of the analysis of the spectra indicate the influence of doping silicon with holmium on its structure and properties, forming new bonds and defects.

Mechanism of Change in The Emission and Optical Properties of W and Mo After Bombardment with Low-Energy Ions

D.А. Tashmukhamedova — 2024-06-01

The paper reports the results of study of composition, emission, and optical properties of polycrystalline W and Mo samples implanted with Ba⁺ ions and coated with submonolayer Ba atoms by applying Auger electron spectroscopy, secondary electron emission coefficient s technique, as well as the photoelectron quantum yield Y. The experimental part was carried out by using the instrumentation and under vacuum Р ≈ 10^-6 Pa. It is shown that during the implantation of Ba ions in the surface layers of refractory metals, a mechanical mixture of the W + Ba and Mo-Ba types is formed. It has been established that the values of the coefficient of secondary electron emission s and the quantum yield of photoelectrons Y at the same value of the work function еφ in the case of implantation of Ba⁺ ions are much larger than in the case of deposition of atoms. The obtained experimental results are substantiated by theoretical calculations.

Defective Structure of Silicon Doped with Dysprosium

Khodjakbar S. Daliev — 2024-06-01

In this work, the structural and optical characteristics of silicon (n-Si) samples and its compositions with dysprosium (n-Si-Dy) were analyzed using Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy methods. Characteristic peaks in the FTIR spectra such as 640 cm^-1 (Si-H mode) and 1615 cm^-1 (perpendicular stretching mode) were identified, indicating the structural features of the material. The appearance of additional peaks in the n-Si-Dy spectra at 516.71 cm^-1 and 805 cm^-1 indicates the influence of dysprosium on the structure and defectiveness of the material. Examination of the frequency range (1950–2250 cm^-1) further confirms local vibration modes associated with defects and interactions with dysprosium. Peaks associated with Dy-Dy stretching, as well as interaction with silicon, were found at 2110 cm^-1 and 2124 cm^-1. Analysis of Raman spectra indicates the formation of silicon nanocrystals during annealing, which is confirmed by XRD results. The results obtained provide important insight into the effect of dysprosium on the structure and properties of silicon materials, which could potentially find application in optoelectronics and materials science.

Defect Structure of Silicon Doped with Erbium

Sharifa B. Utamuradova — 2024-06-01

The study of thin-film nanocomposites, including crystalline and amorphous silicon nanoparticles embedded in silicon oxide layers, is a key direction in the field of materials for optoelectronics. This study explored the interest in such composites, including erbium silicide (ErSi_2-x), in the context of their applications in non-volatile memory and photovoltaic devices. Particular attention was paid to the structure and properties of such materials, including the analysis of defects in erbium-doped silicon. The results of the study, based on Raman spectroscopy and X-ray phase analysis, made it possible to identify the characteristics of the composition and structure of the studied samples. The identified data confirmed the presence of crystalline phases of Si and Er in the p-Si-Er composite, and also showed the substitution of Er in the p-Si/SiO₂ structure. Additionally, X-ray microanalysis data confirmed the presence of Si, O and Er in the expected concentrations in the composite film. Further research showed that the introduction of erbium atoms onto the silicon surface leads to minor changes in some signals and the appearance of new vibrations in the Raman spectra of the samples. The decrease in the intensity of the peaks belonging to silicon is associated with the weakening and breaking of some bonds in the structure of the silicon crystal lattice and due to the formation of new bonds in which erbium atoms participate. Thus, the results of this study represent a significant contribution to the understanding of the properties and potential of thin film nanocomposites for applications in optoelectronics, and also enrich our knowledge of the effect of doping on the structure and properties of silicon materials.

Surface Properties and Composition Analysis of Nano-Sized Thin Films of CDSE: by SEM Analysis

L.N. Ibrahimova — 2024-06-01

Thin films of cadmium selenide with a thickness h = 200-500 nm were obtained and their surface properties were studied. The studies were carried out using a Scanning Electron Microscope. It was found that with increasing thickness of thin layers, the surface structure becomes smoother. A compositional analysis of the surface of thin layers was also carried out. Elemental analysis was carried out in layers of various thicknesses, the percentage content of chemical elements and the energy spectrum of chemical elements were determined. It has been established that thin CdSe films obtained by chemical deposition are quite pure. The surface of thin layers with a thickness h > 400 nm turned out to be quite smooth, which is an indicator of the formation of a phase in these layers corresponding to the CdSe compound.

Study of Crystal Characterization and Chemical Interaction in the Ternary System Ho-Sb-Te

T.M. Ilyasli — 2024-06-01

Complex methods of physical and chemical analysis: differential thermal analysis (DTA), X-ray phase analysis (XRD), microstructural analysis (MSA), as well as density and microhardness measurements, were used to study the nature of chemical interaction in the Ho-Sb-Te ternary system over the entire concentration range along the following sections:1. Sb₂Te₃-Ho₂Te₃, 2. Sb₂Te₃-HoTe, 3. HoTe-Sb, 4. HoSb-HoTe, 5. Sb₂Te₃-Ho, 6. HoSb-Te. The projection of the liquidus surface of the ternary system and the diagrams of the state of internal sections were constructed according to experimental data and literature data on binary systems: Sb-Te, Sb-Ho, Ho-Te. It is established that sections (1), (2), (3), (4) are quasi-binary, and (5), (6) are non-quasi-binary sections of the ternary system. The incongruently melting compound HoSbTe₃ is formed in the Sb₂Te₃-Ho₂Te₃system and the area of solid solutions based on Sb₂Te₃~ 3‑5 mol% at 300K was found.

Morphology of the Surface of Silicon Doped with Lutetium

Khodjakbar S. Daliev — 2024-06-01

In this paper, using a scanning electron microscope (SEM) and atomic analysis, the location map of microcomposites formed on the surface of n-Si, p-Si, n-Si<Lu> and p-Si<Lu> samples was studied. Force microscope (AFM) research devices. The atomic fractions of inclusions of carbon, oxygen and lutetium formed on the surface of the samples were studied. Also, using the ASM device, the sizes, relief and topographic appearance of defects formed on the surface of the samples were determined. In silicon samples doped with Lu, a decrease in the size of surface defects and the formation of nano-sized structures were found, which makes it possible to obtain materials with a more perfect crystal structure. Using a ZEISS GeminiSEM 300 scanning electron microscope, the structural structure, chemical composition and images of their arrangement of n-Si, p-Si, n-Si<Lu> and p-Si<Lu> samples were obtained. In this case, the electron accelerating voltage was 20 kV, and the pressure in the sample chamber was (10^-3mmHg). Research results show that the structural structure of micro- and nanocomposites formed in silicon mainly depends on the diffusion time and cooling rate of the samples after diffusion annealing.

Nanocrystalline ZnO Films on Various Substrates: A Study on Their Structural, Optical, and Electrical Characteristics

Numonjon A. Sultanov — 2024-06-01

Zinc oxide (ZnO), characterized by its wide bandgap and substantial exciton binding energy, is extensively utilized in optoelectronic applications, including blue and ultraviolet light-emitting diodes (LEDs) and lasers. In this study, the deposition of ZnO films on various substrates (Si, sapphire, GaAs, GaP) through thermal oxidation is investigated as a cost-effective alternative to molecular beam epitaxy (MBE) and chemical vapor deposition (CVD). A thorough analysis of the structural, optical, and electrical properties of these films is presented, with a focus on their suitability for heterojunction diodes. The methodology employed involved the thermal evaporation of Zn films in a vacuum chamber, followed by oxidation in a pure oxygen atmosphere. The conditions for deposition were optimized to yield nanocrystalline ZnO films with a preferential orientation, as confirmed by X-ray diffraction (XRD) analysis. An increase in the optical bandgap was indicated by optical transmittance measurements, while photoluminescence (PL) spectra exhibited uniform and enhanced crystalline integrity across the samples. The electrical characterization of ZnO-based heterojunction diodes on different substrates revealed distinct electrical characteristics, with variations in leakage current and ideality factor observed. The specific resistances of the Zinc Oxide (ZnO) films were determined by analyzing the linear portions of the current-voltage (I-V) curves.

Investigation of Structural, Magnetic and Optical Properties for Dysprosium Doped Zinc Nanoferrites by Sol-Gel Autocombution Techniques

Sanchita V. Chavan — 2024-06-01

Using the auto combustion sol-gel method, nanoferrite crystalline aligns of Dy³⁺replaced Zn-Fe spinel ferrite with the chemical formula Dy_xZn_1-xFe_2-xO₄ (x= 0.00, 0.05) were successfully synthesized. In this process, citric acid was utilized as energy (fuel) in a 3:1 ratio to metal nitrate. Using XRD and FT-IR, the crystal structure and phase of dysprosium zinc was examined. Using the XRD method, the crystal size, lattice constant, cation distribution, and porosity were ascertained. FT-IR spectroscopy is used to infer structural study and the redistribution of cations between octahederal (A) and tetrahederal (B) site of Zn material. According to morphological research, the temperature during sintering is what causes grain to form and grow. Utilizing the Hysteresis Loop Technique, saturation magnetism and magneton number are determined. In Zn-Fe ferrite, the saturation magnetization rises with increasing density x, utilizing the Sol-gel auto-combustion method at a comparatively low temperature. Using nitrate citrate, the nanocrystallite Dy_xZn_1-xFe_2-xO₄ was created. The combustion process and chemical gelation are unique. Using citric acid as a catalyst, their metal nitrates nanoferrites underwent a successful chemical reaction and were obtained as a dried gel. FT-IR, UV-Visible, VSM and XRD were used to characterize the produced nanoferrite powders. Magnetization and hysteresis were measured using the VSM technique. The FT-IR verifies that the synthesized substance is ferrite. The size of the nanocrystalline ferrite material, Dy_xZn_1-xFe_2-xO₄, was determined by X-ray using the Scherrer method to be between 16.86 to 12.72 nm average crystallite size. Magnetization and hysteresis were measured using the VSM technique.

Effect of γ-Irradiation on Structure and Electrophysical Properties of S-Doped ZnO Films

Sirajidin S. Zainabidinov — 2024-06-01

The produced ZnO<S> films were characterized with the crystallographic orientation (001) and lattice parameters a = b = 0.3265 nm and c = 0.5212 nm. ZnO_1—хS_х nano-crystallites on the surface of the film had characteristic sizes ranging from 50 nm to 200 nm. The lattice parameter of ZnO_1—хS_х nano-crystallites was experimentally determined to be a_ZnO<S>= 0.7598 nm. The study has shed light on what occurs to lattice parameters of the ZnO film and the geometric dimensions of ZnO_1—хS_х nano-crystallites on the surface of the film under the influence of gamma-irradiation. It has been determined that the crystal structure of ZnO_1—хS_х nanocrystallites represents a cubic lattice and belongs to the space group F43m. It has been determined that after γ-irradiation at doses 5∙10⁶ rad, the resistivity of ZnO<S> films reduced to ρ = 12,7 W∙cm and the mobility of the majority charge carriers (µ) became 0.18 cm²/V∙s, whereas their concentration (N) had increased and equaled 2.64∙10¹⁸cm^-3. The study of the current-voltage characteristics of p- ZnO<S>/n-Si heterostructures before and after γ‑irradiation at doses of 5∙10⁶ rad revealed that the dependence of the current on voltage obeys an exponential law which is consistent with the theory of the injection depletion phenomenon. It was determined that under the influence of γ-irradiation at doses of 5∙10⁶ rad, the capacitance of the p-ZnO<S>/n-Si heterostructure at negative voltages increases and the shelved curve sections and peaks are observed on the curve due to the presence of a monoenergetic level of fast surface states at the heterojunction.

Influence of Gold on Structural Defects of Silicon

Sharifa B. Utamuradova — 2024-06-01

In this research, a comprehensive study of the effect of doping silicon with gold on the optical properties and morphology of silicon layers was carried out. For this purpose, the methods of Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used. The results of the study showed that the transition from original silicon to gold-doped silicon leads to significant changes in the optical properties and morphology of the layers. Raman spectra showed characteristic peaks in the regions of 144, 304, 402, 464, 522, 948 and 973 cm^–1, associated with the violation of long-range order of the crystal lattice and the interaction of gold with silicon. The intensity and position of the peaks in the spectra allowed us to draw conclusions about structural changes, including a decrease in crystallinity and the formation of amorphous and nanocrystalline structures in the samples after treatment at 1373 K. New peaks in the Raman spectra associated with Au-Au stretching and the formation of new bonds Si-Au, confirm the processes in silicon layers when alloyed with gold. SEM studies provided information on the structure, chemical composition and arrangement of n-Si-Au and p-Si-Au samples. The spherical arrangement of gold atoms on the surface of single-crystalline silicon was experimentally established, which indicates the diffusion of gold and the formation of gold silicate, which introduces a positive charge to the interface. Morphological changes included an increase in the number of agglomerates with nanocrystals smaller than 7–9 nm and an increase in the transparency of the layer. These results indicate the possibility of improving the photosensitivity of heterostructures with a Si–Au composite layer due to the quantum-size and plasmonic effects of inclusions containing silicon and gold nanoparticles.

X-Ray Structural and Photoelectric Properties of SnO2, ZnO, and Zn2SnO4 Metal Oxide Films

Khotamjon J. Mansurov — 2024-06-01

The conditions and parameters for the synthesis of metal oxide films (ZnO, SnO₂, and Zn₂SnO₄) by spray pyrolysis have been determined. The films were synthesized from aqueous solutions; the main differences between the methods were in the composition of the precursors, in the modes and time of deposition. The crystal structure of the Zn₂SnO₄ film corresponds to the cubic lattice, which belongs to the space group Fd3m with blocks 53 nm in size and lattice parameters a = 6.238 Å. Films of SnO₂ and ZnO nanocrystallites 28 and 31 nm in size coherently arranged with lattices in the volume of thin Zn₂SnO₄ films can exhibit quantum size effects, which is of interest for modern nanotechnology. The crystals of the obtained SnO₂ films have a tetragonal Bravais lattice with the space group P4 2/mnm with lattice parameters a = b = 4.836 Å and c = 3.245 Å, and the size of the SnO₂ film subcrystals is 61 nm. The resulting ZnO films belong to the C6/mmc space group and the crystal lattice has a hexagonal syngony with the wurtzite structure with parameters a = b = 0.3265 nm and c = 0.5212 nm. It has been determined that, on the surface of the thin film grown, zinc oxide bumps with sizes L_ZnO ≈ 84 nm appear, which affect the unique properties of the samples. It is shown that the resulting thin Zn₂SnO₄, SnO₂, and ZnO films can be used in a wide range of applications from sensitive sensor elements to coatings in transparent electronics in terms of their optical parameters.

Study of the Inhomogeneities of Overcompensed Silicon Samples Doped with Manganese

M.Sh. Isaev — 2024-06-01

Inhomogeneities in the near-surface region of diffusion-doped silicon with manganese atoms were studied using the local photo-EMF method and photovoltage and photoconductivity signals were detected. It has been established that the inhomogeneous region is located at a depth of 3÷35 μm from the surface of the crystal. The magnitude of photo-EMF in these layers does not change monotonically from point to point. It was revealed that the photo-EMF spectra depend on the wavelength of the irradiated light, while the shape of the areas and their shift are related to the penetration depth of laser radiation. The photo-EMF signal increases to a depth of ~25 µm from the surface, then saturates and from ~30 µm smoothly decreases and completely disappears at a depth of ~40 µm. The magnitude of the internal electric field was determined using the Tauc method. A model of the structure of the near-surface region of diffusion-doped silicon with manganese is proposed.

Effect of Structural Defects on Parameters of Silicon Four-Quadrant p-i-n Photodiodes

Mykola S. Kukurudziak — 2024-06-01

The article examines the influence of structural defects, in particular dislocations, on the electrical and photovoltaic properties of silicon four-quadrant p-i-n photodiodes. It was established that growth defects and defects formed during mechanical processing of plates can cross the entire substrate and deteriorate the parameters of photodiodes. This phenomenon is particularly negative due to the placement of defects in the space charge region. In this case, due to the presence of recombination centers in the space charge region, the life time of minor charge carriers decreases and the dark current and responsivity of photodiodes deteriorate. Often, the placement of defects is uneven, which provokes unevenness of parameters on responsive elements. It was also seen that the dislocation lines crossing the responsive elements and the guard ring worsen the insulation resistance of the specified active elements. A method of determining the final resistivity of silicon and the diffusion length of minor charge carriers by studying the pulse shape of the output signal is proposed.

Structural Features of Silicon with Tin Impurity

Sharifa B. Utamuradova — 2024-06-01

In this work, samples of single-crystalline silicon doped with tin were studied using X-ray diffraction and electron microscopy. It has been established that at a scattering angle of 2θ » 36.6° in the X-ray diffraction patterns of n-Si and Si<Sn> samples, structural reflections (110) of the corresponding SiO₂ nanocrystallites with lattice parameters a = b = 0,4936 нм и c = 0,5212 nm and c = 0.5212 nm, belonging to the hexagonal crystal lattice and space group P3₂1. The formation of tin nanocrystallites with sizes of 9.1 and 8 nm in the near-surface regions of the Si<Sn> matrix crystal lattice was discovered.

CVC Structure of PtSi - Si-M in a Wide Range of Temperatures

Abdugafur T. Mamadalimov — 2024-06-01

In this work the mechanism of current flow during illumination with hν≥E_g in the temperature range of 77÷300 K is considered. It is established that in the PtSi – Si<Pt>-M structure in the temperature range of 77÷270 K the regime of space charge limited currents (SCLC) is realized. The current-voltage characteristics of the structures show areas of linear and quadratic dependences of current on voltage, as well as areas of a sharp increase in current. These features of the current-voltage characteristic are explained by the presence of deep level structures and sticking levels for charge carriers in the base region. From the temperature dependence of the SCLC, the concentration of adhesion levels was determined to be equal to (1.8÷3) 10¹⁵ cm^-3 and the adhesion factor to be equal to 6.32·10^-2. In the temperature range 77÷115 K at voltages 0.2÷1 V, the current-voltage characteristic obeys the law J ~ Uⁿ(n=3÷4), and above U – the law J ~ U⁶, followed by a transition to the quadratic law.

Study of the Thermoelectric Properties of Chrome Silicides

Abdugafur T. Mamadalimov — 2024-06-01

The temperature dependences of the thermoelectromotive force of chromium mono and disilicides in the temperature range 200℃÷+600℃ have been studied. For chromium disilicide, the dependence of the thermopower coefficient (α) on temperature (T) has three sections. Chromium monosilicide is characterized by a smooth increase in thermopower with increasing temperatures up to 200℃, and then its constancy. It was revealed that silicides rich in chromium atoms have lower thermopower values than silicides rich in silicon. The maximum thermo-EMF values of 110 μV/K and 190 μV/K were observed for chromium mono- and disilicides, respectively. It was revealed that for chromium silicides the dependence of the dimensionless parameter Q = Z∙T on temperature is linear. The possibility of predicting the technology of synthesis of semiconductor material with optimal thermoelectric properties using the dependence of thermopower on conductivity and the parameter Q on temperature is shown.

Study of Silicide Formation in Large Diameter Monocrystalline Silicon

Abdugafur T. Mamadalimov — 2024-06-01

To study the formation of silicides, dislocation-free ingots of single-crystalline silicon with a diameter of 65÷110 mm, grown by the Czochralski method, were used. When studying such silicon samples using electron microscopy, small-angle scattering of CO₂ laser radiation, three types of defects were identified: swirl defects, impurity micro inclusions and impurity clouds. It has been shown that silicide inclusions with sizes of 8-20 μm are formed in the near-surface layer of doped silicon, and they decrease linearly deeper into the crystal. The electrical parameters of semiconductor chromium silicide were determined: resistivity 1800 μOhm·cm, thermopower coefficient 180 μV/k, Hall constant 1.2·10^-2 cm³/Kl, hole concentration 6·10¹⁹ cm^-3, charge carrier mobility 18.6 cm²/V·s, band gap (0.29±0.02) еV.

Comparison of 2D and 3D p-n Junction Differential Conductance and Diffusion Capacitance

Muhammadjon G. Dadamirzaev — 2024-06-01

In the fabrication of 3D p-n junctions, doping or surface modification caused by ion injection changes the electrical properties and crystal structure of the semiconductor. In addition, as the size of the semiconductor device decreases, various quantum effects are gradually appearing in them. This shows that the scope of application of classical device theory is now limited. In recent years, two-dimensional (2D) materials with amazing atomically fine properties have attracted great interest. The electrostatic field properties of some 2D p-n junctions, such as WS2, MoS₂, MoSe₂, WSe₂, and black phosphorus (BP), open the door to new possibilities for semiconductors. Changes in the diffusion capacitances and differential conductance’s of 2D p-n junctions under the influence of an microwave field, and the diffusion capacitances and differential conductance’s of 2D and 3D p-n junctions the change of conductivities under the influence of microwave field is compared.

Influence of Different Types of Radiation on the Crystal Structure of Silicon Monocrystals n-Si

Sharifa B. Utamuradova — 2024-06-01

In this work, the influence of alpha particles, protons and gamma rays on the crystal structure and structural characteristics of n-type silicon (n-Si) single crystals was studied using X-ray diffraction. N-type silicon (KEF-40) was used for the study. The samples were irradiated with protons with a dose of 9×10¹⁴ cm^-2 with an energy of 600 keV and a current of 1÷1.5 µA, irradiated with alpha particles with a dose of 6×10¹⁴ cm^-2 with an energy of 800 keV and a current of 0.5÷1 µA and γ− ⁶⁰Co quanta with a flux intensity of ~ 3.2×10¹² quantum/cm²·s. Based on the results of X-ray diffraction analysis, it was established that distortions, vacancies and amorphization of lattice parameters that arose after irradiation lead to an increase in lattice parameters.

Electrodifusion of Manganese Atoms in Silicon

Xalmurat M. Iliyev — 2024-06-01

The paper describes the research and study of the process of electrically induced diffusion of Mn atoms in silicon directly from a Si surface layer that was preliminarily enriched with Mn. To ensure the so-called electrically induced diffusion process, a constant electric field was applied to the investigated samples. It has been revealed that as a result of the diffusion of Mn impurity atoms into samples placed at the negative pole of the electrical diffusion unit, the proportion of Mn atoms was 75.4% (relative to silicon atoms), while in samples placed at the positive pole this indicator tended to be 2.7% (relative to silicon atoms). Besides that, for the first time, an experimental increase in the electro-active concentration of Mn impurity atoms in silicon (at T = 900°C) was detected under the influence of an external constant-value electric field. In this case, the maximum solubility of impurity atoms of Mn at a temperature of T = 900°C was N_Mn~2.27·10¹⁴ cm^-3, while the average concentration of electro-active Mn atoms diffused into silicon under the influence of an external constant electric field reached N_Mn^*~2.62·10¹⁴ cm^-3.

Electric Field Enhancement by Gold Nano-Sphere and Its Clusters

P.K. Kushwaha — 2024-06-01

The confinement of electrons in gold nanoparticles results in Surface Plasmon Resonance (SPR), which is characterized by electric field enhancement in the vicinity of these nanoparticles. This property has been extensively studied and applied in various fields. In our research, we conduct a detailed investigation of plasmonic coupling in spherical gold nanoparticles. Specifically, we use the Discrete Dipole Approximation (DDA) method implemented in DDSCAT to simulate the coupling of electric fields in a doublet of nanoparticles as a function of the distance between them. Our simulations show that the coupling of SPR between two nanoparticles occurs up to a separation of 12 nm. Moreover, we extend our simulations to study the coupling of nanoparticles in linear chains consisting of up to five nanoparticles and in clustered forms. Our results indicate that the SPR coupling in a linear chain occurs, and as the number of nanoparticles increases, the field enhancement also increases. However, we observe that this effect saturates after four nanoparticles in a line. Our study provides insights into the plasmonic coupling in gold nanoparticles, which can aid in the design and optimization of plasmonic devices for various applications.

Specific Features of Carbon Nanoparticle Formation Under the Influence of a Laser Operating in a Double-Pulse Generation Mode

Maria I. Markevich — 2024-06-01

This study investigates the morphology of carbon nanoparticles generated through the ablation of an MPG-6 carbon target in an aqueous environment. The ablation process utilized an LS-2134D aluminum yttrium garnet laser (wavelength: 1064 nm) operating in a double-pulse mode (pulse separation: 3 μs, pulse duration: 10 ns, pulse repetition rate: 10 Hz, single pulse energy: ~0.05 J). The results demonstrate the formation of a diverse range of carbon nanoparticles with varying sizes and shapes during laser ablation. Additionally, the study showcases the ability to control the ablation process and subsequent synthesis of carbon nanoparticles, achieving efficient generation of nanoparticles suitable for various applications.

Implications of the Presence of Y As a Reactive Element in Cathodic Vacuum ARC TiAlN Protective Coating for Tribological Applications

О.V. Maksakova — 2024-06-01

The results of studies of the influence of Y as a reactive element on the properties of TiAlN coatings obtained by the method of vacuum-arc deposition are given. Changes in the structure and properties were analyzed using SEM in combination with EDX, XRD, indentation analysis and wear analysis. It is shown that the presence of Y changes the crystalline phase of the Ti_0.6Al_0.34Y_0.06N coating. It consists of a combination of a cubic NaCl structure (basic phase) and a wurtzite structure (additional phase). In addition, it leads to a small grain size (12 nm) and a nano-columnar structure. The high hardness is partly the result of solution hardening due to the inclusion of larger Y atoms in the TiAlN lattice at the locations of the metal atoms. The reduced grain size of 12 nm also helps to increase the hardness of the coating. The hardness is 31 ± 2.5 GPa, the modulus of elasticity is 394.8 ± 35.8 GPa. The residual stress is approximately three times (−3352 ± 64 MPa) higher than the TiAlN coating (−720 MPa). In addition, a high level of compressive stress contributes to an increase in hardness, since defects responsible for their own compressive stress are an obstacle to dislocation movement. The improved hardness of the experimental coating can be explained by a triple effect: solution strengthening, grain grinding and high residual compressive stress. The addition of Y indicates a slower growth of the oxide layer on the surface of the coating during the wear test. After the addition of Y, Y ions preferentially separate at the grain boundaries and therefore effectively delay the inward diffusion of oxygen. The addition of Y promotes the formation of dense Al₂O₃, which is effective in restraining diffusion and therefore protects the coating from oxidative wear.

Vibrational Frequencies of Phosphorus Trichloride with the Vibrational Hamiltonian

J. Vijayasekhar — 2024-06-01

This study presents an approach for precisely determining the stretching vibrational frequencies of the P-Cl bond in phosphorus trichloride (PCl₃) using a vibrational Hamiltonian framework that maintains the C_3v symmetry point group. Our methodology enables the accurate prediction of vibrational frequencies up to the fifth overtone. It identifies related combination bands, marking a significant advancement in vibrational spectroscopy and molecular modelling. By enhancing the accuracy and depth of our understanding of molecular vibrations, this research paves the way for developing more sophisticated computational models, thereby significantly improving the precision of chemical analyses, and contributing to the broader field of chemical physics.

Higher Overtone Vibrational Frequencies of Cyclobutane-D8 Using Lie Algebraic Framework

A. Ganapathi Rao — 2024-06-01

This research study employs a Lie algebraic framework to investigate the second and third overtone vibrational frequencies and their combination bands in cyclobutane-d8 (C₄D₈). The application of this framework ensures the preservation of the point symmetry group D_2d, characterized by the symmetry species A₁, A₂, B₁, B₂, and E. The analysis encompasses 23 normal vibrational modes within the molecular structure of cyclobutane-d8. Our study extensively explores the vibrational spectra, elucidating the intricate interactions among these vibrational modes. Preserving molecular symmetry allows for a deeper understanding of vibrational interactions, offering valuable insights into spectroscopy. The research enhances the comprehension of molecular structure and its applications in various fields, providing a detailed view of higher energy levels and complex vibrational transitions in cyclobutane-d8.

Structure and Properties of Interpolymer Complexes Based on Sodium Carboxymethylcellulose Polysaccharide and Carbopol

Sabitjan Ya. Inagamov — 2024-06-01

In this paper, the structure and properties of interpolymer complexes (IPC) based on sodium carboxymethylcellulose with a linear carbopol were studied. Interpolymer complexes were obtained by mixing aqueous solutions of Na-CMC and carbopol components in various ratios of components and pH of the medium. The structure of the obtained products was determined using the methods of IR spectroscopy and X–ray diffraction analysis. IR spectra in the range of 400-4000 cm^-1 were recorded on spectrophotometers "NIKOLET Magna-560 IR" and "Specord–75 IR" (Karl Zeiss, GDR). X-ray diffraction analysis of IPС films was carried out on a Rigaku X-Ray installation with an X-ray generator with a rotating copper anode, at a voltage of 40 kV, with a current strength of 15 mA and using characteristic Cu-Ka radiation in the area of angles 0 <2θ <40. IR spectroscopic data show that the interpolymer complexes based on Na-CMC and carbopol obtained in moderately acidic regions are stabilized due to the cooperative hydrogen bond between the carboxyl groups of Na-CMC and the carbonyl groups of carbopol. X-ray diffraction analysis has shown that a change in the composition of the interpolymer complex leads to a change in the structure, which depends on the structure and nature of the interchain bonds. It is ascertained that an increase in the number of hydrogen bonds leads to a more ordered state of the resulting interpolymer complex. It is revealed that the formation of an interpolymer complex due to hydrogen bonds provides additional stability. This can serve as one of the means of controlling the structure and properties of the IPC of sodium carboxymethylcellulose with carbopol.

Radiation Graft Copolymerization of Vinyl Fluoride to Cotton, Hydrocellulose Fiber and Fabric

Fozilbek Z. Jamoldinov — 2024-06-01

Cellulose-based materials are not in short supply and are characterized by relatively low cost. On the other hand, cellulose fibers have a wide range of valuable physical, chemical and mechanical properties that make them indispensable in a number of sectors of the national economy. Along with valuable qualities, natural and artificial cellulose fibers also have some disadvantages that limit their use in technology and in the national economy. These are low resistance to the action of microorganisms, relatively low heat resistance, chemical resistance, flammability, etc., which reduce their service life and limit their scope. One of the ways to eliminate these shortcomings is the modification of natural and artificial macromolecular compounds by chemical and physicochemical methods. Improving the properties of cellulose and its derivatives can be achieved by various modification methods, among which one of the most promising is the radiation-chemical grafting of various monomers. One of the advantages of this method, in comparison with others, is the production of field worlds that are not contaminated with impurities, the presence of which can adversely affect their physicochemical properties. Another advantage is the relative ease of formation of macroradicals necessary to initiate the process of graft copolymerization. Quite a lot of work has been devoted to the radiation grafting of various monomers to cellulose and its derivatives; at present, some of them are beginning to be widely used in the national economy. In the light of the foregoing, the grafting of fluorine-containing monomers, the polymers and copolmers of which have such very valuable and specific properties as high heat resistance, chemical resistance, light resistance, decay resistance and hydrophobicity to cellulose and its derivatives, is of great scientific and practical interest. This work is the synthesis of graft copolymers of cotton cellulose with vinyl fluoride by the radiation-chemical method from the vapor phase, the study of the effect of radiation dose rate, reaction time, the presence and nature of solvents on the course of this process and the yield of graft copolymers, as well as the study of such important physical and chemical properties and operational properties of the original, irradiated and grafted copolymers, such as sorption capacity and density, hydrophobicity and swelling, degree of whiteness, mechanical properties, thermal stability, the nature of the change in the supramolecular structure as a result of grafting fluorine-containing polymers.

Enhancing Solar Cell Conversion Efficiency Through Evolutionary Optimization Using Genetic Algorithms

Brahim Lakehal — 2024-06-01

In this study, we propose a new method based on genetic algorithms to optimize the performance of intermediate-band solar cells (IBSC). Our approach aims to maximize photovoltaic conversion efficiency by judiciously optimizing the geometric and physical parameters of the IBSC structure., which must be partially filled. This filling ensures the presence of both empty states in the intermediate band (IB) to receive electrons from the valence band (VB), and filled states to provide electrons to the conduction band (CB). Recently, studies have observed the effect of IB occupancy on cell efficiency, and calculated the optimal efficiency for IB devices. The analytical expression for optimal IB filling has been utilized for different scenarios involving IB-CB coupling strength and IB region width. In this work we have studied the influence of the intermediate band energy level, the effects of doping on efficiency, short-circuit current, open-circuit voltage, fill factor, and in order to validate our approach on parasitic effects such as series and shunt resistance.

Enhancing Third-Generation Solar Cell Efficiency and Stability Through P-Type Silicon Integration: Process Analysis and Performance Evaluation

Santosh Kumar Srivastava — 2024-06-01

Third-generation solar cells have emerged as a potential solution to the effectiveness and stability issues encountered in conventional solar technology. This study focuses on the characteristics of copper-zinc-tin-sulfide (CZTS) thin films inside this innovative architectural framework, which is an important step toward improving third-generation solar cells by incorporating a p-type silicon layer. This integrated method provides a versatile and manageable setting for film deposition, underscoring the effort put into creating high-quality CZTS thin films. Using X-ray diffraction (XRD), the study assessed the structural change of CZTS films after annealing, finding that kesterite phases were dominant. Images captured by a scanning electron microscope (SEM) reveal the microstructure and surface morphology of CZTS-coated Silicon nanowires (Si-NWs). A detailed analysis of the current-voltage characteristics provides evidence of the operational potential of the Si-NWs-CZTS coated solar cell. Significant performance parameters observed include a Voc value of 0.45 ± 0.02V, Isc value of 8.25 ± 0.30 mA/cm², FF value of 24 ± 2%, and η value of 1.0 ± 0.1%. The encouraging results indicate the capacity of using P-type silicon to enhance the performance of third-generation solar cells.

SCAPS Numerical Analysis of Graphene Oxide/Zirconium Disulfide Solar Cells

Hmoud Al-Dmour — 2024-06-01

This work studies the performance of solar cells composed of two different materials, graphene oxide (Go, hole transport material) and zirconium disulfide (ZrS_2,electron transport materials) using the SCPAS -1D simulation. It has been found that Go/ZrS₂ solar cells show better performance with high short circuit current, J_sc, of 38 mA/cm² and the power conversion efficiency, η, of 17% compared with other solar cells based on graphene oxide and perovskite materials. Additionally, the short circuit current density decreases from 38 mA/cm² to 22 mA/cm² when the energy gap of ZrS₂ increases from 1.2 eV to 17 eV. The increasing the operating temperature and the work function of back contact also led to decrease the open circuit voltage and power conversion efficiency of the cells, while the short circuit current density was slightly enhanced. That is attributed to changes in the electrical properties of Go and ZrS₂ layers, including their charge carrier mobility and characteristics of the interfacial layers.

Multiband Asymmetric Biconical Dipole Antenna with Distributed Surface Impedance and Arbitrary Excitation

Mikhail V. Nesterenko — 2024-06-01

A numerical-analytical solution of a problem concerning the current distribution and input characteristics of asymmetric biconical dipole with distributed surface impedance and arbitrary excitation and derived in the thin-wire approximation. Solution correctness is confirmed by satisfactory agreement of numerical and experimental results from literary sources. Numerical results are given for the input characteristics of the dipole in the case of its asymmetric excitation by a point source.

Antenna Based on Complicated Coplanar Structure

Sergey A. Pogarsky — 2024-06-01

This paper presents the results of a numerical study of a planar antenna with a complex form factor. The antenna is based on a combination of two resonators, a disc resonator and a ring resonator. The feeding of the ring resonator is performed using a coplanar structure: pointwise by galvanic contact between the central conductor of the coplanar line and the ring resonator and by distributed electromagnetic coupling of the ring resonator and the aperture of the outer conductor of the coplanar line. The antenna was placed over a metal plane whose geometric dimensions were significantly larger than those of the antenna to exclude the influence of edge diffraction effects. In numerical simulation a complex approach including the method of semi-open resonator and the finite element method (FEM) implemented within the commercial package HFFS was used. The dependences of spectral, energy and polarization characteristics on material constants and frequency parameter have been investigated. It was found that within the framework of single-parameter optimization it is impossible to simultaneously achieve a high level of all important parameters. The values of frequencies of spectral lines in the spectral characteristics of the antenna are found with a relative error not worse than 1200 Hz. Frequency ranges within which there is no degeneration of oscillation types are established. The distributions of surface currents on the metal elements of the antenna, allowing to determine the position of phase centers of excitation, are presented. It is shown that the proposed antenna can provide an acceptable level of matching both at fixed frequencies and in sufficiently wide local frequency bands, reaching 11% with respect to the center frequency of the sub-band. The boundary values of gain coefficients in frequency bands are established. The simulation results allow to predict effective radiation with formation of practically single-lobe radiation pattern and presence of elliptical polarization.

Interactions of Amyloid Fibrils with Functional Proteins: Modulating Effect of Polyphenols

Valeriya Trusova — 2024-06-01

The elucidation of interactions between functional proteins and amyloid fibrils is crucial for understanding the molecular basis of amyloid diseases, which are characterized by protein misfolding and aggregation. Polyphenols, due to their diverse biological properties, have garnered attention for their potential to modulate these protein-fibril interactions, thereby influencing disease progression and offering therapeutic possibilities. In this study, we investigated the effects of quercetin and its binary combinations with other polyphenols on the binding affinity between cytochrome c, in both its reduced and oxidized forms, and amyloid fibrils of insulin and apolipoprotein A-I. Our results demonstrate that quercetin complexation with cytochrome c decreases the binding affinity of insulin fibrils for both forms of the protein, while increasing the affinity for apolipoprotein A-I fibrils. This modulation was attributed to competitive or allosteric effects exerted by quercetin on cytochrome c. Additionally, while binary combinations of quercetin with other polyphenols did not reduce the affinity of insulin fibrils for oxidized cytochrome c, they did decrease the affinity in the case of reduced counterpart. These findings highlight the selective and significant impact of polyphenolic compounds on the interactions between amyloid fibrils and functional proteins, suggesting potential pathways for therapeutic intervention in amyloid-related disorders.

Deciphering the Molecular Details of Interactions Between Heavy Metals and Proteins: Molecular Docking Study

O. Zhytniakivska — 2024-05-27

Understanding the interaction of heavy metals with proteins is pivotal for unraveling their roles in biochemical processes and metal-induced diseases, with wide-ranging implications spanning medicine, environmental science, and biotechnology, thereby driving progress in therapeutics, pollution mitigation, and biomaterial innovation. In the present study the molecular docking technique was employed to identify and characterize the binding sites of the set of heavy metals (Cu2+, Fe3+, Mg2+, Mn2+, Zn2+, Cd2+, Fe2+, Ni2+, Hg2+, Co2+, Cu+, Au+, Ba2+, Pb2+, Pt2+, Sm3+, and Sr2+) and proteins ((β-lactoglobulin, 7S globulin and glycinin from soybeans) to evaluate the impact of protein structure on their ion-binding abilities and selectivity. Our docking results indicate that essential and toxic heavy metals interact with multiple binding sites of proteins, presumably by electrostatic interactions and metal chelation with cysteine, aspartic acid, glutamic acid, and histidine amino acid residues. The comparison of binding residues favorable for heavy metal complexation among different proteins indicates that metals exhibit distinct preferences for various amino acid residues highlighting the importance of both the metal and the protein properties for stabilizing protein-metal complexation.

Erratum: Permittivity Model Selection Based on Size and Quantum-Size Effects in Gold Films

Iuliia Riabenko — 2024-06-01

The purpose of this Erratum is to correct a misprint presented in the original article:

Riabenko, S. Shulga, N.А. Makarovskii, K. Beloshenko, "Permittivity Model Selection Based On Size And Quantum-Size Effects In Gold Films," East Eur. J. Phys. 3, 406-412 (2023). https://doi.org/10.26565/2312-4334-2023-3-44