East European Journal of Physics

The Role of Surface in Hydride Formation Processes

Viktor O. Litvinov, Ivan I. Okseniuk, Dmytro I. Shevchenko, Valentyn V. Bobkov — Mon, 04 Sep 2023 00:00:00 +0000

Several LaNi₅-based hydrogen storage alloys were studied using secondary ion mass spectrometry (SIMS) technique. Ar⁺ ions with the energy of 10 - 18 keV were used as primary ions. The study of the initial stages of the processes of LaNi₅-based alloys interaction with hydrogen under the experimental conditions showed that on the areas of clean surface, hydrogen formed chemical compounds with the both of the main components of the alloy: nickel and lanthanum. As hydrogen accumulates on the surface and in the near-surface region, a hydrogen-containing structure is formed, which is characterized by a certain stoichiometric ratio of components. Nickel in this structure has strong chemical bonds with two hydrogen atoms, and lanthanum – with two or more hydrogen atoms. Along with such compounds, some structures with lower hydrogen content are also formed. The formed hydrogen-containing structure includes both main alloy components, La and Ni for all the studied samples, even though only lanthanum is generally accepted to be the hydride-forming element in such alloys. The SIMS studies of the chemical composition of the surface monolayers of the intermetallic alloy LaNi₅, in the process of its interaction with oxygen, showed the following. As a result of the oxygen interaction with the alloy, a complex chemical structure including oxygen, lanthanum and nickel is formed on the surface and in the near-surface region of LaNi₅. Oxygen in such a structure, similarly to hydrogen, forms strong chemical bonds with both components of the alloy. This is indicated by the presence in the mass spectra of a large set of oxygen-containing emissions of positive and negative secondary ions with lanthanum and nickel, as well as oxygen-containing lanthanum-nickel cluster secondary ions. The formed oxide compounds have a three-dimensional structure and occupy tens of monolayers. Oxygen poisoning of the surface of the hydride-forming alloy LaNi₅ can occur regardless of whether the surface of the alloy was clean from the very beginning or it was covered with a layer of hydrogen-containing chemical compounds.

Anisotropic Cosmological Model in f (R,T) Theory of Gravity with a Quadratic Function of T

Chandra Rekha Mahanta, Shayanika Deka, Kankana Pathak — Mon, 04 Sep 2023 00:00:00 +0000

In this paper, we study spatially homogeneous and anisotropic Bianchi type-I space-time filled with perfect fluid within the framework of f(R,T) theory of gravity for the functional form f(R,T)=R+2f(T) with f(T)=αT+βT², where α and β are constants. Exact solutions of the gravitational field equations are obtained by assuming the average scale factor to obey a hybrid expansion law and some cosmological parameters of the model are derived. Two special cases, leading to the power-law expansion and the exponential expansion, are also considered. We investigate the physical and geometrical properties of the models by studying the evolution graphs of some relevant cosmological parameters such as the Hubble parameter (H), the deceleration parameter ( q) etc.

Energy Conditions and Statefinder Diagnostic of Cosmological Model with Special Law of Hubble Parameter in f(R, T) Gravity

V.R. Patil, P.A. Bolke, S.K. Waghmare, J.L. Pawde — Mon, 04 Sep 2023 00:00:00 +0000

In this article, we examine the LRS Bianchi type-I cosmological model in the framework of f(R, T) gravity, where R is the Ricci scalar and T is the stress energy momentum tensor in the presence of Domain wall. we used the special law of variation of Hubble’s parameter proposed by Berman (1983) to obtained the exact solution of field equation, corresponds to the model of the universe. The Energy conditions and physical behaviour of the universe has been obtained and their evolution has been discussed using some physical parameter and by means of their graphs. Also, we can use the Statefinder parameter for testing the validity of the model.

Energy Conditions with Interacting Field in f(R) Gravity

Vasudeo Patil, Jeevan Pawde, Rahul Mapari, Pravin Bolke — Mon, 04 Sep 2023 00:00:00 +0000

In the context of current scenario, it is crucial to look beyond Einstein’s theory, which opens the door to certain modified theories of gravity. So, present study is devoted to investigate the various energy conditions, particularly, strong energy condition (SEC), weak energy condition (WEC), null energy condition (NEC) and dominant energy condition (DEC) corresponding to different functional forms of f(R) gravity. We have studied for flat, isotropic and homogeneous FLRW cosmological model filled with interacting field i.e., perfect fluid is coupled with mass less scalar field for different models of modified f(R) gravity in which R is the Ricci scalar. We have observed, the accelerated expansion of the Universe which exact match with recent observational evidences.

A Study of Evolution of Cosmological Parameters Based on Dark Energy Models in Kaluza-Klein Framework

Sudipto Roy, Asmita Das, Anwesha Dey, Debolina Biswas, Sudipto Saha Roy — Tue, 18 Jul 2023 00:00:00 +0000

The purpose of the present study is to determine the characteristics of time evolution of various cosmological quantities, based on four models constructed for a universe undergoing accelerated expansion. This formulation is done in the framework of Kaluza-Klein space-time, for zero spatial curvature. To solve the field equations, an ansatz is chosen for each model in such a way that it leads to a signature flip of the deceleration parameter, to ensure its consistency with recent astrophysical observations indicating a change from a decelerated expansion to an accelerated expansion of the universe. Based on these four models, time evolutions of several cosmological parameters are obtained and their variations are shown graphically against time. The arbitrary constants, associated with each model, are so tuned that the model correctly predicts the values of the Hubble parameter, deceleration parameter, energy density and gravitational constant at the present time. The findings from these models are consistent with each other, and they are in agreement with the observed features. The gravitational constant (G) shows a rapid fall in the early universe, followed by an extremely slow rise which continues at the present time. Taking (G) as a constant in two of the four models, the cosmological constant is found to be independent of time. A significant finding is that the signature flip of the deceleration parameter almost coincides with the signature flip of the cosmological constant (Λ), pointing towards a relation between the accelerated expansion and the dark energy which is represented by Λ. Other plots with respect to Λ also depict dark energy’s role in governing cosmic evolution. Considering its dynamical nature, Λ is referred to as cosmological term (instead of cosmological constant) in the text. Contrary to the common trend of using arbitrary units, the SI units for all measurable quantities are used.

Renyi Holographic Dark Energy Model in f(R) Gravity with Hubble's IR Cut-Off

Kishor S. Wankhade, Alfred Shaikh, Siraj N. Khan — Mon, 04 Sep 2023 00:00:00 +0000

In the present study, a homogeneous and anisotropic LRS Bianchi type-I universe model is considered with an interacting dark matter and Renyi holographic dark energy model (RHDE) in f(R) gravity. The deceleration parameter (DP) shows a signature flipping for a universe which was decelerating in past and accelerating at present epoch. Therefore, the DP is a most physically justified parameter to analyze the solution of cosmological model. In order to find an exact solution of the field equations of the model, the shear scalar is considered to be proportional to the expansion scalar. We have considered f(R) = b Rⁿ, the depiction model of f(R) which is the function of Ricci scalar R. The physical and geometrical characteristics of the universe model have been studied.

A Study of Evolution of Cosmological Parameters Based on a Dark Energy Model in the Framework of Brans-Dicke Gravity

Mon, 04 Sep 2023 00:00:00 +0000

The objective of the present study is to find the characteristics of evolution of a homogeneous and isotropic universe in the framework of Brans-Dicke (BD) theory of gravity. FLRW space-time, with zero spatial curvature, has been used to obtain BD field equations. Scale factor and Hubble parameter have been obtained from an ansatz for the deceleration parameter, assumed on the basis of its property of signature flip indicating a change of phase from deceleration to acceleration. Validation of the model has been achieved by a suitable parametrization of that ansatz. Expressions for energy density, pressure, equation of state (EoS) parameter, cosmological constant, gravitational constant have been derived and depicted graphically. The gravitational constant is found to decrease with time at a gradually decreasing rate. The Hubble parameter, deceleration parameter and energy density decrease with time, which is in agreement with many other studies. The value of the EoS parameter at the present epoch is negative, and it becomes more negative with time. The cosmological constant increases very rapidly in the early universe from negative to smaller negative values, becoming positive finally, with a much slower change thereafter. A cosmographic and a geometrical analysis have been carried out. It is observed that a gradual transition takes place from a regime of quintessence to phantom dark energy. An important finding of this study is that the signature flip of the deceleration parameter takes place almost simultaneously with the signature flip of the cosmological constant, implying a connection between accelerated expansion and dark energy, which is represented here by the cosmological constant. Unlike the common practice of using arbitrary units, proper SI units for all measurable quantities have been used. This theoretical investigation provides the reader with a simple method to formulate models in the framework of BD theory.

Five - Dimensional Plane Symmetric Cosmological Model with Quadratic Equation of State in f(R,T) Theory of Gravity

V.A. Thakare, R.V. Mapari, S.S. Thakre — Mon, 04 Sep 2023 00:00:00 +0000

In this paper, we analysed the five-dimensional plane-symmetric cosmological model containing perfect fluid in the context of f(R, T) gravity. Field equations have solved for two class of f(R, T) gravity i.e., f(R, T) = R + f(T) and f(R, T) = f₁(R)f₂(T) with the inclusion of cosmological constant Λ and quadratic equation of state parameters in the form p = αρ² − ρ, where α is a constant and strictly α≠ 0. In order to derive the exact solutions, we utilize volumetric power law and exponential law of expansion. The physical and geometrical aspects of model have discussed.

Generation of O-Mode in the Presence of Ion-Cyclotron Drift Wave Turbulence in a Nonuniform Plasma

Banashree Saikia, P.N. Deka — Mon, 04 Sep 2023 00:00:00 +0000

This study aims to investigate the effect of ion-cyclotron drift wave turbulence on the generation of ordinary mode (O-mode) in the presence of density and temperature gradients. For this, a Vlasov plasma is considered where a resonant, and non-resonant modes are considered to be present in the system. Here, the non-resonant mode is a perturbation caused by O-mode in a quasi-steady state of plasma, which is characterised by the presence of low frequency ion-cyclotron resonant mode waves. The interaction between these waves is studied by the Vlasov-Maxwell set of equations and a modified Maxwellian-type distribution function for particles that includes the external force field and associated density and temperature gradient parameters . The study analyses the growth rate of electromagnetic O-mode at the expense of ion-cyclotron drift wave energy and the associated impact of the density and temperature gradient. This model uses the linear response theory on weakly turbulent plasma, evaluates the responses due to turbulent and perturbed fields, and obtains the nonlinear dispersion relation for O-mode.

Determination of the Dependence of the Oscillation of Transverse Electrical Conductivity and Magnetoresistance on Temperature in Heterostructures Based on Quantum Wells

Ulugbek I. Erkaboev, Rustamjon G. Rakhimov — Mon, 04 Sep 2023 00:00:00 +0000

In this work, the influence of two-dimensional state density on oscillations of transverse electrical conductivity in heterostructures with rectangular quantum wells is investigated. A new analytical expression is derived for calculating the temperature dependence of the transverse electrical conductivity oscillation and the magnetoresistance of a quantum well. For the first time, a mechanism has been developed for oscillating the transverse electrical conductivity and magnetoresistance of a quantum well from the first-order derivative of the magnetic field (differential) at low temperatures and weak magnetic fields. The oscillations of electrical conductivity and magnetoresistance of a narrow-band quantum well with a non-parabolic dispersion law are investigated. The proposed theory investigated the results of experiments of a narrow-band quantum well (In_xGa_1-xSb).

Comparative Study of the Mass Spectra of Heavy Quarkonium System with an Interacting Potential Model

Mon, 04 Sep 2023 00:00:00 +0000

In this work, the comparison of the mass spectra of heavy quarkonium system with an interacting potential (Class of Yukawa potential) was studied. The Schrodinger equation is analytically solved using Nikiforov- Uvarov (NU) method and series expansion method (SEM). The approximate solutions of the eigen energy equation and corresponding eigenfunction in terms of Laguerre polynomials were obtained using the NU method and the solutions of the eigen energy equation were also obtained with the SEM. The mass spectra for heavy quarkonium system (HQS) for the potential under study were obtained for bottomonium and charmonium HQS. We compared the results obtained between NU and SEM. It was noticed that SEM solutions yield mass spectra very close to experimental data compared to solutions with NU method. The obtained results were also compared with works by some other authors and were found to be improved. This study can be extended by using other exponential-type potential models with other analytical approach and a different approximation schemes to obtain the mass spectra of heavy quarkonium system. The relativistic properties using Klein-Gordon or Dirac equations can be explored to obtain the mass spectra of light quarkonia. Finally, the information entailed in the normalized wave-functions can also be studied.

Bound State and Ro-Vibrational Energies Eigenvalues of Selected Diatomic Molecules with a Class of Inversely Quadratic Yukawa Plus Hulthén Potential Model

Fina O. Faithpraise, Etido P. Inyang — Mon, 04 Sep 2023 00:00:00 +0000

The Nikiforov-Uvarov approach is used in this study to solve the Schrödinger equation utilizing a class of inversely quadratic Yukawa plus Hulthén potential model with an approximation to the centrifugal term. The normalized wave function and energy eigenvalue equation were obtained. The numerical bound state for a few diatomic molecules (N₂, O₂, NO, and CO) for various rotational and vibrational quantum numbers was calculated using the energy equation and the related spectroscopic data. Our results show that, with no divergence between the s-wave and l-wave, the energy eigenvalues are very sensitive to the potential and diatomic molecule properties, suggesting that the approximation approach is appropriate for this set of potentials. The results are consistent with earlier studies in the literature, and we also found four special cases of this potential.

Deformation of Odd Nuclei 27Al, 31P and 35Cl in Single-Particle States

Volodymyr Yu. Korda, Larisa P. Korda, Vyacheslav F. Klepikov, Iryna S. Timchenko — Mon, 04 Sep 2023 00:00:00 +0000

Using the evolutionary approach recently developed by us, the shapes of odd s-d-shell ²⁷Al, ³¹P and ³⁵Cl nuclei in the ground and single-particle excited states have been extracted from the experimental data on the energies, spins, and parities of these states, as well as the measured probabilities of electromagnetic transitions between them. The key ingredient of our procedure is the evolutionary algorithm that evolves the population of the bad-quality data-fitting nuclear shapes to the high-quality data-fitting nuclear shapes. We have found that the studied nuclei in the ground states are abnormally weakly deformed, which is not expected for the nuclei in the shell middle. Even in their low-laying single-particle excited states, the nuclei ²⁷Al and ³¹P are found to be weakly deformed, too. With the increase of the single-particle excitation energy, the change of the state of the only one nucleon – the valence proton the spin and parity of which determine the spin and parity of the ³⁵Cl nucleus – causes the shape phase transition from the high-symmetry phase – spherical ground state – to the low-symmetry phase – deformed excited states. The angular part of the ²⁷Al and ³¹P nuclei shape is described by two harmonics – quadrupole and hexadecapole. The angular part of the ³⁵Cl nucleus shape is described by three harmonics – quadrupole, hexadecapole, and hexacontatetrapole, but the contribution of hexadecapole deformation is not independent. At present, there are no fundamental nuclear models that account for or predict the dominant hexacontatetrapole deformation, especially for light and medium nuclei. We have found that the spin and parity of the ²⁷Al, ³¹P and ³⁵Cl nuclei are determined by the spin and parity of the last odd (valence) proton. At the same time, some of the nucleons of the nucleus core change their characteristics, too. Thus, the electromagnetic transitions between the single-particle states of the ²⁷Al, ³¹P and ³⁵Cl nuclei are the multi-particle processes.

The Effect of the Proton and Neutron as Probe for the Nuclear Fusion Reactions at Near-Barrier Energies

M. A. Khuadher, F.A. Majeed — Mon, 04 Sep 2023 00:00:00 +0000

In this study, quantum mechanical calculations and a semi-classical approach were used to determine fusion the probability (P_fus), fusion barrier distribution (D_fus), and fusion cross section (σ_fus) for the systems ²⁸Si + ⁹⁰Zr, ²⁸Si + ⁹²Zr, ²⁸Si + ⁹⁴Zr, ⁴¹K + ²⁸Si, and ⁴⁵K + ²⁸Si. The semiclassical approach involved the use of the WKB approximation to describe the relative motion between the projectile and target nuclei, and the Continuum Discretized Coupled Channel (CDCC) method of Alder-Winther (AW) to describe the intrinsic motion of the nuclei. The importance of the neutron and the proton transfer and exchange on the calculations of P_fus, D_fus, and σ_fus for the studied systems. The results showed that the consideration of the coupling-channel calculations for quantum mechanics and a semi-classical approach, are very important to be considered specifically around and below the Coulomb barrier. The results were compared with the measured data and found in reasonable agreement.

Nuclear Energy Levels Scheme of 46Cr Using FPD6, FPY, and KB3G Interactions

Hasan A. Kadhim, Firas Z. Majeed — Mon, 04 Sep 2023 00:00:00 +0000

The ⁴⁶Cr isotope nuclear energy levels were studied using low-level FP-LS shell inside the shell model calculations. Nuclear energy levels have been calculated using FPD6, KB3G, and FPY interactions in the fp-shell model space and F742 and F7MBZ in the f7/2 model space. The results are compared to one another and to the experimental data that is already accessible and specific outcomes are clearly in agreement. In addition to having a strong arrangement in the reproduced values of the energy levels scheme, the used model space interactions are the two-body matrix element in the fp-shell model space that is best fitted. Particularly below 3 MeV, the general estimation of the replicated data is good. The wave vectors and analysis are modeled in diagrammatic notation, and all inscriptions are given in this style. Utilizing the oscillator's potential, a single particle vector is built, using ⁴⁰Ca as the core of the fp-shell and f7/2 model space. Results are obtained for all tested nuclei using the OXFORD BUENOS AIRES SHELL (OXBASH) model code.

The influence changing of Nuclear Potential on Quasi-Elastic Scattering in 16O+160Gd and 12C+197Au Systems

Farah J. Hamood, Khalid S. Jassim — Mon, 04 Sep 2023 00:00:00 +0000

In this research, the effect of changing the potential depth V₀ on the Quasi-elastic scattering and barrier distribution calculations have been studied using Wood-Saxon (WS) potential for ¹⁶O+¹⁶⁰Gd and ¹²C+¹⁹⁷Au systems. The chi square (χ2) is applied to compare the best fitted value of the diffuseness parameter between the theoretical calculations and the experimental data. The diffuseness parameter which used in this work is to be at standard value 0.63. The χ² was applied to most suitable the better fitted value of the potential depth V₀. According to the results, we noticed that some systems achieved a good match between the theoretical calculations and experimental data of Quasi-elastic scattering (dσqel/dσR) and the distribution calculations at the standard value of the potential depth or at a value lower than the standard value and no match was achieved at a value greater than the standard value of the potential depth V₀. We conclude that the values of quasi-elastic scattering values increase when the value of potential depth decreases.

A Study the Nuclear Potential Using Quasi-Elastic Scattering Calculation for the 9,10,11Be+208Pb Reactions

Ali A. Rakhees, Khalid S. Jassim — Mon, 04 Sep 2023 00:00:00 +0000

Specific systematic studies on the nuclear potential parameter for the heavy-ion reactions, which includes the systems, have been achieved by using large-angle quasi-elastic scattering at deep sub-barrier energies close to the Coulomb barrier height. Single-channel (SC) and coupled-channel calculations have been carried out to elicit the nuclear potential. The chi-square method χ2 has been used to find the best value of the nuclear potential compared to the experimental data. The best values of the nuclear potential were found from the calculations of the coupled channels for an inert projectile and a vibrating target for systems: ⁹Be+²⁰⁸Pb,¹⁰Be+²⁰⁸Pb, ¹¹Be+²⁰⁸Pb, which are equal to 45 MeV,65 MeV,53 MeV, respectively.

Investigating the Effect of Gravity Modulation on Weakly Nonlinear Magnetoconvection in a Nonuniformly Rotating Nanofluid Layer

Michael I. Kopp, Volodymyr V. Yanovsky — Mon, 04 Sep 2023 00:00:00 +0000

This paper investigates the impact of gravity modulation on weakly nonlinear magnetoconvection in a nanofluid layer that is nonuniformly rotating. The fundamental equations are obtained for the Cartesian approximation of the Couette flow using the Boussinesq approximation and gravitational modulation. The weakly nonlinear regime is analyzed using the method of perturbations with respect to the small supercritical parameter of the Rayleigh number, considering the effects of Brownian motion and thermophoresis in the nanofluid layer. Heat and mass transfer are evaluated in terms of finite amplitudes and calculated from the Nusselt numbers for the fluid and the volume concentration of nanoparticles. The findings demonstrate that gravitational modulation, nonuniform rotation, and differences in the volume concentration of nanoparticles at the layer boundaries can effectively control heat and mass transfer. Additionally, the negative rotation profile has a destabilizing effect. The study shows that the modulated system conveys more heat and mass than the unmodulated system.

The Effects of Thermal Stratification on Flow Past an Infinite Vertical Plate in Presence of Chemical Reaction

Rupam Shankar Nath, Rudra Kanta Deka — Mon, 04 Sep 2023 00:00:00 +0000

This study examines how thermal stratification affect the movement of a fluid in presence of first order chemical reaction past an infinite vertical plate. To solve the non-dimensional governing equations in closed form for Pr = 1, the Laplace’s transform system is applied. Significant findings resulting from stratification are compared to the case of no stratification. The effects of many parameters, including S, K, Gr, Gc, Sc and time on velocity, temperature, concentration, skin friction, Nusselt number, and Sherwood number are explored and graphically displayed. It is shown that the steady state is attained at shorter times as a result of the application of stratification on the flow.

Investigation of Thermal Radiative Tangent Hyperbolic Nanofluid Flow Due to Stretched Sheet

Muhammad Jawad, Mubeen Alam, Kottakkaran Sooppy Nisar — Mon, 04 Sep 2023 00:00:00 +0000

The current study illuminates the enactment of a tangent hyperbolic nanofluid past a bidirectional stretchable surface. The phenomena of heat and mass transfer with joule heating, chemical reaction, and thermal radiation have been debated. For the motivation of the problem, convective boundary conditions are part of this study. The modeled partial differential equations are mended into ordinary differential equations with the help of appropriate self-similarity transformations. Furthermore, the resulting system of ODEs is numerically handled by using well-established shooting scheme and acquired numerical outcomes are compared with ND Solve command of Mathematica. The Effects of prominent parameters on velocity, temperature and volumetric concentration distribution are inspected through graphs. The influence of emerging parameters involved in this study on flow and heat removal features are deliberated in detail. As we are increasing the values of power-law index n, Prandtl number Pr and Magnetic parameter M, outcomes increment in skin friction coefficient while decline in the Nusselt number is seen.

Slow Electromagnetic Surface TM-Waves in Planar Waveguide Structure with Mu-Negative Metamaterial Slab

Mon, 04 Sep 2023 00:00:00 +0000

In this work, we study the properties of slow electromagnetic surface TM-waves propagating along the planar waveguide structure involving the mu-negative metamaterial slab. The planar mu-negative metamaterial layer separates two semi-infinite regions: the plasma and the conventional dielectric. All media are assumed to be linear, homogeneous, and isotropic. The dispersion properties, the phase and group velocities, the spatial distribution of the electromagnetic fields of the TM mode in frequency range where the metamaterial has a negative permeability are under the consideration. The properties of this TM-eigenwave of the structure and two other TE modes are compared. It is studied the TM-eigenwave properties variation with metamaterail and plasma-like media properties changing. It is shown that for the considered structure, the properties of the TM mode depend significantly on the parameters of the plasma-like medium.

The Parametric Generalized Fractional Nikiforov-Uvarov Method and Its Applications

M. Abu-Shady, H.M. Fath-Allah — Mon, 04 Sep 2023 00:00:00 +0000

By using generalized fractional derivative, the parametric generalized fractional Nikiforov-Uvarov (NU) method is introduced. The second-order parametric generalized differential equation is exactly solved in the fractional form. The obtained results are applied on the extended Cornell potential, the pesudoharmonic potential, the Mie potential, the Kratzer-Fues potential, the harmonic oscillator potential, the Morse potential, the Woods-Saxon potential, the Hulthen potential, the deformed Rosen-Morse potential and the P schl-Teller potential which play an important role in the fields of molecular and atomic physics. The special of classical cases are obtained from the fractional cases at which are agreement with recent works.

First-Principles Calculation of Structural, Electronic, and Optical Properties of Cubic Perovskite CsPbF3

Zozan Y. Mohammed, Sarkawt A. Sami, Jalal M. Salih — Mon, 04 Sep 2023 00:00:00 +0000

Lead halide perovskites have attracted considerable attention as one of the most promising materials for optoelectronic applications. The structural, electronic, and optical properties of the cubic perovskite CsPbF₃ were studied using density functional theory in conjunction with plane waves, norm-conserving pseudopotentials, and Perdew-Berg-Erzenhof flavor of generalized gradient approximation. The obtained structural parameters are a good agreement with the experimentally measured and other’s theoretically predicted values. The obtained electronic band structure revealed that cubic CsPbF₃ has a direct fundamental band gap of 2.99 eV at point R. The calculated energy band gaps at the high symmetry points agree with the other available theoretical results. The GW method is adapted to correct the underestimated fundamental energy gap value to 4.05 eV. The contribution of the different bands was analyzed from the total and partial density of states. The electron densities show that Cs and F have strong ionic bonds, whereas Pb and F have strong covalent bonds. The optical properties of CsPbF₃ were calculated using the density functional perturbation theory and Kramers-Kronig relations. The wide and direct bandgap nature and the calculated optical properties imply that cubic CsPbF₃ can be used in optical and optoelectronic devices for high frequencies visible and low frequencies ultraviolet electromagnetic radiation.

Eco-Friendly Green Synthesis and Photocatalyst Activity of Ag-ZnO Nanocomposite

Noorullah Mohammed Nemma, Zainab Sabeeh Sadeq — Mon, 04 Sep 2023 00:00:00 +0000

The study successfully synthesized Ag NPs, ZnO NPs, and Ag/ZnO nanocomposites using an easy, cost effect and sustainable green synthetic approach. The purpose of synthesizing Ag/ZnO nanocomposites using two different plant extracts was to study their photo-degradation activity on Methylene Blue (MB) dye. (XRD) diffraction analysis confirmed the presence of Ag crystalline size and the wurtzite hexagonal structure of ZnO. (FE-SEM) results indicated spherical, nanorods and there is Clustering of NPs with an irregular shape. The resulting metal/semiconductor oxide nanocomposites possessed unique photo degradation characteristics that were absent in the individual Ag NPs and ZnO NPs.

A Comparative Study of Microstructure and Properties of Multicomponent Coatings Based On (TIZRSIY)N System Prepared by the Vacuum ARC Deposition

Mon, 04 Sep 2023 00:00:00 +0000

The effect of reaction gas (nitrogen) pressure on the structural-phase state and properties of vacuum-arc nitride coatings of (TiZrSiY)N system has been studied. On the surface of the coatings, a significant amount of the droplet fraction and solidified macroparticles of the sputtered cathode is observed, which is typical for vacuum-arc condensates obtained from unseparated plasma flows. In all samples, titanium nitride with a cubic fcc lattice is identified. In the coatingobtained at nitrogen pressures 0.08 Pa and 0.2 Pa, the α-Ti phase was determined, and the measured lattice parameter of this phase suggests that it is a solid solution of nitrogen in titanium. The texture coefficient of the multicomponent coating obtained at the highest nitrogen pressure of 0.55 Pa has the highest value of 5.95 compared to others. The Vickers hardness of multicomponent coatings increases depending on the partial pressure of nitrogen from 25.0 GPa to 36.0 GPa. According to the complex of tribo-mechanical parameters (hardness, elastic modulus, elastic strain to failure, friction coefficient etc.), suggested multicomponent (TiZrSiY)N coatings can be very attractive for tribological applications.

The Effect of Thermal Annealing on the Electrophysical Properties of Samples n-Si

Nozimjon A. Turgunov, Elmurod Kh. Berkinov, Raymash M. Turmanova — Mon, 04 Sep 2023 00:00:00 +0000

This paper presents the results of studies of the effect of isothermal annealing at temperatures T = 673¸1473 K in the time interval 5¸60 minutes on the electrical properties of silicon, simultaneously alloyed with nickel and copper. Samples of n-Si<Ni,Cu> were obtained on the basis of the starting material - single-crystal silicon, grown by the Czochralski method with the initial resistivity r = 0.3 Ohm×cm. Diffusion was carried out at a temperature of 1523 K for 2 hours. After that, the samples were cooled at a rate of 0.1 K/s. The morphological parameters of impurity nickel and copper atom clusters formed in the bulk of silicon were measured by electron probe microanalysis on a modern Superprobe JXA-8800R setup. As it turned out, in the volume of n-Si<Ni,Cu> samples, clusters of impurity atoms with different geometric shapes are formed, the sizes of which reach up to 500 nm. The electrical properties of the samples were studied by the Hall effect method using an Ecopia HMS-7000 instrument. It was revealed that under the influence of thermal annealing (TA) at T≥1273 K, impurity clusters decompose, which leads to an increase in the resistivity of n‑Si<Ni,Cu> samples. After exposure to TA at Т=1273 K for 15 minutes, the density of impurity nanoaccumulations of acicular and lenticular shapes sharply decreases in the sample volume. Under the influence of TA at T = 1473 K for 10 minutes in the volume of the sample, the decay of impurity nanoclusters with a spherical shape is observed. Also presented are the results of changes in the density of impurity clusters, as well as structural analyzes of the samples before and after exposure to thermal annealing.

Properties of “Higher Manganese Silicide-Silicon” Heterostructure

Kobiljon K. ugli Kurbonaliev, Nurulla F. Zikrillaev, Akhmadjon Z. Khusanov — Mon, 04 Sep 2023 00:00:00 +0000

Based on the diffusion technology, many scientists and specialists have conducted research on obtaining materials that are fundamentally different in electrical and photo-thermal parameters from the original material by introducing various input atoms into semiconductor materials and creating deep energy levels in their band gap. The electrical, photoelectric, optical, and magnetic properties of these semiconductor materials have been extensively studied with metal group elements, isovalent elements, and rare earth elements added to silicon through the process of growth, ion implantation, or diffusion from the gaseous state. The technology of introducing impurity atoms into silicon by the diffusion method is distinguished from other methods in its simplicity, energy efficiency, and low cost. Up-to-date, the technology of changing the resistivity and conductivity of the initial sample by diffusion of manganese atoms into single-crystal silicon is studied insufficiently. In the article, it was determined that when manganese atoms diffuse into silicon, a high-manganese silicide is formed on its surface and in the near-surface layer. Based on the analysis of the experimental results, the thermal EMF (electromotive force) in Mn₄Si₇-Si -<Mn>-Mn₄Si₇ structures in a certain temperature range and under illumination (with monochromatic or integrated light) is explained by the fact that it based on the Pelte effect, observed in semiconductors.The volt-ampere characteristics (VAC) of the obtained structures were measured at various temperatures, in the dark and in the light. Formation of a boundary layer with high resistivity at the boundary of the higher manganese-silicon transition, the transition from higher manganese silicide to the base of the structure due to the effect of ionization of pores during illumination of structures and external influence. The applied field was clarified based on VAC results. The manganese high silicide layer formed on the silicon surface has the properties of a semiconductor, and the formation of a heterojunction upon transition to silicon is shown on the basis of the sphere diagram.

Effect of ZnS and CdS on Some Physical Properties of MgO Films

N.A. Hassan, W.H. Albanda, M.H. Al-Timimi — Mon, 04 Sep 2023 00:00:00 +0000

This article reports on the fabrication and characterization of MgO nanostructured films and the effect of ZnS and CdS on their structural, optical, and electrical properties. The MgO, MgO: ZnS, and MgO: CdS thin films were deposited using a Chemical spray pyrolysis technique onto glass substrates at 673 K. The XRD patterns revealed that the MgO thin films had a preferred (111) orientation with a pure cubic crystalline structure, while the ZnS and CdS layers had a hexagonal structure. The FE-SEM images showed that the MgO films had a nanostructured morphology with an average particle size of ~50 nm. The UV-Vis spectroscopy results showed that the addition of ZnS and CdS layers to the MgO films resulted in a shift in the absorption edge towards the visible region of the electromagnetic spectrum, indicating an improvement in their optical properties. These findings suggest that the MgOZnS and MgOCdS films could have potential applications in optoelectronic devices.

A Surface Study of Si Doped Simultaneously with Ga and Sb

X.M. Iliyev, Sobir B. Isamov, Bobir O. Isakov, U.X. Qurbonova, S.A. Abduraxmonov — Mon, 04 Sep 2023 00:00:00 +0000

The paper is concerned with the study of silicon samples doped with gallium (Ga) and antimony (Sb) atoms. In particular, the elemental analysis, SEM imaging, and Raman spectrometry analysis of the samples are presented. The elemental analysis revealed that the relative concentrations of Ga (0.4) were almost equal to those of Sb (0.39) and both were formed on the surface of Si. The SEM imaging showed that GaSb microsized islands (diameter of 1 to 15 microns) and a density of ~10⁶ cm^-2 were being formed on the surface of Si in the course of the process of diffusion doping. Raman spectral analysis showed that a semiconductor with GaSb molecules self-assemble on Si surface.

Optical and Magnetic Response of Pure and CU-Ions Substituted Dysprosium Oxide Thin Films for Various Applications

Muhammad Tauseef Qureshi — Mon, 04 Sep 2023 00:00:00 +0000

Dysprosium oxide (Dy₂O₃) and Cu/Dy₂O₃ thin films of thickness 117.14 nm and 258.30 nm, respectively were successfully deposited via a well-known DC-magnetron sputtering technique. Field emission scanning electron microscopy clarifies the growth of uniform and fine granular particles on silicon substrate. The hexagonal closed pack structure for both the thin films has been observed by the x-ray diffraction analysis and it was observed that by inclusion of copper the HCP structure of thin film was retain with a slight shift in the main peak. The reduction from 3.9 eV to 3.8 eV in the energy band gap value was observed by incorporation of copper ions Dy₂O₃ thin films. The M-H loops obtained through Vibrating Sample Magnetometer (VSM) shows that Dy₂O₃ thin film behave ferromagnetically at low temperature with a saturation magnetization value of 2860 emu/cc and evolves through its phase transition temperatures and behave paramagnetically at room temperature. In Cu/Dy₂O₃ case, the diamagnetic response of Cu dominates and produces reverse hysteresis loop at both temperatures make it a suitable candidate for energy and memory storage devices applications.

Structural and Optical Prperties of (ZnO/NiO) Thin Films Mixture

Mon, 04 Sep 2023 00:00:00 +0000

In this study, we prepared mixtures of nickel oxide (NiO) and zinc (ZnO) in different proportions as thin films on high-purity glass substrates, using pyrolysis spray technique. Where samples of mixtures were precipitated from two solutions of nickel nitrate (Ni(NO₃)₂ ·6H₂O) and zinc acetate (C₄ H₆O₄ Zn·2H₂O) mixed in different proportions. Then the optical and structural properties of the prepared samples were studied. The transmittance decreases with the increase in the percentage of nickel oxide, which means that increasing the zinc oxide improves the transmittance in all the studied spectral fields. Samples with higher zinc oxide (ZnO) have two energy gaps. Scanning electron microscopy (SEM) showed that the surface morphology of the films has a relatively homogeneous composition. Where it was observed that increasing the proportion of zinc oxide leads to the appearance of zinc oxide granules clearly.

Investigation the Structural Influences of Silver Oxide Addition in the Bioactive Phosphate Glasses

Ruqaya H. Hussian, Dunia K. Mahdi — Mon, 04 Sep 2023 00:00:00 +0000

This research investigates the impact of varying concentrations of silver oxide on the structure and morphology of phosphate bioactive glass (PBG). PBGs are gaining popularity as a potential replacement for traditional silicate glasses in biomedical applications due to their adjustable chemical resistance and exceptional bioactivity. Upon examination of the scanning electron microscope of the composites without Ag₂O, it was observed that the grains tended to merge together, and the surface particles appeared to be larger than those in composites with Ag₂O at concentrations of 0.25, 0.5, and 0.75 wt%. The study found that the diffraction pattern of phosphate bioactive glass composites sintered without Ag₂O showed the presence of Strontium di-phosphate and Calcium di-phosphate. The XRD pattern of these composites without Ag₂O revealed specific planes that corresponded to both types of di-phosphate. However, when Ag₂O was added, a new cubic phase was detected, and the intensity of the calcium and strontium diphosphate increased with higher Ag₂O content. The XRD pattern of the composites with Ag₂O displayed specific planes that corresponded to Ag₂O. In other words, the absence of Ag₂O in the composite material led to larger particle sizes and less distinct boundaries between grains. In addition, it has been found that, as the concentration of Ag₂O increased from 0 to 0.25, 0.5, and 0.75 wt%, the average crystallite size decreased from 36.2 to 31.7, 31.0, and 32.8 nm, respectively. These results suggest that the addition of Ag₂O can effectively reduce the average crystallite size of the composite materials. Also, as the concentration of Ag₂O increased from 0 g to 0.5 wt% within the composite material, the average lattice strain increased from 3.41·10^-3 to 4.40·10^-3. In simpler terms, adding Ag₂O to the composite material resulted in a slight increase in the average lattice strain.

Effects of Quantum Confinement Energy on the Transmittance of Cadmium Telluride (CdTe) Within the Near Infrared Region (700-2500nm)

Ali Hussein Hammad Asal, Saeed Naif Turki Al-Rashid — Mon, 04 Sep 2023 00:00:00 +0000

This study investigates how the energy of quantum confinement affects the transmittance of cadmium telluride, because of the importance of this substance, as it crystallizes in the form of cubes as thin films that are used in solar cells and liquid crystal imaging devices, as well as in infrared optics [1]. The MATLAB computer program version (2012a) was used, which is based on the characteristic matrix theory and Brus model, in addition to the quantum confinement energy equation. We found that the transmittance value of the nano CdTe thin film at normal incidence reaches 96.4% at a quantum confinement energy E_co = 2.7eV and at a particle size P_S =2.6nm, while the value reaches 73.6% at a quantum confinement energy E_co= 0.01eV and at a particle size of P_S=50nm.

Current Status of Silicon Studies with GexSi1-x Binary Compounds and Possibilities of Their Applications in Electronics

Mon, 04 Sep 2023 00:00:00 +0000

The paper determines the technological regimes for obtaining Ge_xSi_1-x alloys by introducing germanium atoms into single-crystal silicon by the diffusion method. From the results of the study, it was found that the fundamental parameters of the formed Ge_xSi_1-x alloys differ from the fundamental parameters of the original silicon, in particular, the energy values of the silicon band gap change. Elemental analysis of the surface of the samples showed that the concentration of silicon (in atomic percent) was ~70.66%, germanium ~29.36%. It was assumed that on the silicon surface and in the front part, a thin layer of an alloy of a compound with a composition of approximately Ge_0.3Si_0.7 (0.5÷2 μm) would be formed. Analysis of the spectra (p shows that the spectrum contains peaks ~303 cm^-1 and ~406 cm^-1, corresponding to the Ge-Ge and Si-Ge bonds, respectively. It was also shown that Ge_xSi_1-xbinary compounds are a new material for modern electronics, the possibility of creating properties on their basis in electronics was shown. It is proposed on their basis to create devices with new functionality and highly efficient solar cells.

Study the Effect of Hydrofluoric (HF) Concentration on the Topography of the Porous Silicon Layer Prepared by Sunlight Photochemical Etching (SLPCE)

Mon, 04 Sep 2023 00:00:00 +0000

Silicon nanocrystals have a vast range of potential applications, from improving the efficiency of solar cells and optoelectronic devices to biomedical imaging and drug delivery, wastewater treatment, and antibacterial activities. In this study a photochemical etching technique was used to create layers of porous silicon on a donor silicon wafer with orientation (111) and resistivity equal to 1‑10 ohm·cm. The process involved focusing sunlight onto the samples using a telephoto lens with a suitable focal length of 30cm and a diameter of 90 mm, which provided sufficient energy to complete the chemical etching. By using a constant etching time of 60 minutes and different concentrations of hydrofluoric acid (ranging from 25% to 40%), layers with varying properties were obtained. The resulting surfaces were studied using the atomic force microscope (AFM), revealing the formation of different nanostructures and particles with varying shapes, sizes, and thicknesses depending on the preparation conditions. The average size of the particles was found to be 90.43nm at a concentration of 40% acid, while decreasing to 48.7nm at a concentration of 25% HF acid.

The Effect of Doping on the Electrical Conductivity of Vanadium Oxide (V2O5) Films Doped with Nickel Oxide (NiO) Prepared via Pulsed Laser Deposition (PLD).

Sadon Hassan Hamad, Huda Saadi Ali — Mon, 04 Sep 2023 00:00:00 +0000

In this research, the focus was on examining thin films of vanadium oxide (abbreviated as V₂O₅) with different levels of doping using nickel oxide (NiO) (X = 0, 6, 8)%. The films were created through pulsed laser deposition (PLD) method. The thin films were made and subjected to annealing at 450°C for a duration of one hour. The structural properties of the films were examined using the XRD diffraction technique, whereby the films' composition was found to be polycrystalline, featuring an orthorhombic structure. Notably, the films displayed a prominent alignment along the (111) plane, manifesting at an angle measuring approximately 27.889˚. The FE-SEM technology was utilized to explore and evaluate the surface morphology of the thin films. This showed a nanotube-to-spherical shape transformation. Following the implementation of EDX x-ray technique, it was determined that the films comprised the elemental components of vanadium (V), nickel (Ni), and oxygen (O), consistent with the doping ratios. The assessment of the films' optical properties was carried out through the utilization of UV–visible spectrophotometer, demonstrating decreased absorbance and absorption coefficient, as well as an increased energy gap from 2.32 eV to 2.93 eV. The electrical conductivity results indicated a decrease in direct current conductivity (σ_d.c) with increasing doping ratio, while the activation energy (E_a) increased. Consequently, these films can be utilized in thermoelectric generators.

Effect of Calcination Temperature on Structural and Optical Properties of Nickel Aluminate Nanoparticles

Katrapally Vijaya Kumar, Sara Durga Bhavani — Mon, 04 Sep 2023 00:00:00 +0000

Nickel aluminate (NiAl₂O₄) nanoparticles were synthesized using sol-gel method with auto-combustion. The prepared nanoparticles were made into four parts and calcinated at 700, 900, 1100 and 1300⁰C and taken up for the present study. The taken-up nanoparticles were characterized using powder X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersion X-Ray Spectroscopy (EDS), Fourier Transform and Infrared (FT-IR) spectroscopy and UV-Vis spectroscopy techniques. The X-ray diffraction patterns confirmed the spinel structure and Fd3m space group. Scherrer formula was used to calculate the crystallite size and found in the range 5.78 to 20.55 nm whereas the lattice parameter was found in the range of 8.039 to 8.342 Å. The average grain size was found in the range 142.80 to 187.37 nm whereas interplanar spacing was found in the range of 2.100 to 2.479 Å. The FTIR spectroscopy showed six absorption bands in the range 400 to 3450 cm^-1 and confirmed the spinel structure. The optical band gap (E_g) was decreased with calcination temperature and found in the range 4.2129-4.3115eV.

X-Ray Diffraction and Raman Spectroscopy Analyses of GaSb-Enriched Si Surface Formed by Applying Diffusion Doping Technique

Mon, 04 Sep 2023 00:00:00 +0000

The paper studies the properties of surface and near-surface region of a single crystalline silicon sample doped with atoms of Ga (A^III) and Sb (B^V). n-type single-crystal Si wafers were chosen as substrates, and samples were size of 8×10×0.5 mm³. For diffusion into silicon, Ga and Sb impurities were used with a purity of 99.999 and 99.998, respectively. The authors propose that a new heterostructure might form in the near-surface region of silicon that could be engineered by applying a relatively cheap diffusion method. The experimental and analysis results show that the composition and absorption spectrum of silicon start manifest certain changes, and can be used in the future as a functional material for solar cells. The result showed that randomly located islands with an average diameter of 1–15 µm are formed on the substrate surface. X-ray diffraction analysis was carried out using a Rigaku diffractometer to study the crystallographic parameters of islands formed with the participation of Ga and Sb atoms on the silicon surface. The energy spectrum was studied on Nanofinder High End Raman spectrometer (LOTIS TII) in order to determine the presence of complexes of Ga and Sb atoms within islands formed as a result of diffusion. The optical emission spectra in the new structure were studied using a Lambda 950 spectrophotometer. The measurements were carried out at room temperature, i.e., at 300°K. Having studied the results of X-ray analysis, Raman spectroscopy, and optical spectroscopy, the authors have revealed that Ga and Sb atoms form new Si_0.44(GaSb)_0.56 and Si_0.75(GaSb)_0.25-type binary compounds on Si surface.

Impact of Crystallite Size on Structural, Optical and Magnetic Characteristics of La0.7Sr0.15Ca0.15MnO3 Nanocrystalline

Mohd Abdul Shukur, Katrapally Vijaya Kumar, Gade Narsinga Rao — Mon, 04 Sep 2023 00:00:00 +0000

Nanocrystalline La_0.7Sr_0.15Ca_0.15MnO₃ (LSCMO) manganites were prepared by the combustion process and heated to various annealing temperatures (T_A) to get various sized crystallites. The X-ray diffraction (XRD) patterns provided evidence that a Rhombohedral structure with space group was formed. Additionally, an increase in the size of the crystallites was observed, from 15.64 to 36.78nm, as the temperature (T_A) increased from 700℃ to 1300℃. The FESEM micrographs revealed that homogeneous with porosity. The FTIR spectra showed five absorption peaks. The Optical energy gap of LSCMO nanocrystalline is decreased from 3.51 to 3.28 eV as annealed temperature raised, reveals that the LSCMO nanoparticles are semiconductor in nature. Room temperature Raman spectra of LSCMO nanoparticles demonstrate a notable reliance on annealing temperature. When the Raman modes were analysed with respect to T_A, it was observed that the Raman vibrational phonon mode below 200cm^-1 (A_1g) and four modes (E_g) in the range 200-800cm^-1 displayed significant displacements and widening, which were associated with oxygen sublattice distortion. Considerable changes were observed in both the intensity and full width half maximum (FWHM) of the five Raman modes as the annealing temperature increased. Magnetic behaviour using M-H loop at room temperature were measured by the Vibrating sample magnetometer revealed that gradation of saturation magnetization as the function of annealing temperature. Hence there is a remarkable crystallite size effect on optical and magnetic properties of LSCMO nanocrystallites.

Magnetic Properties of Silicon with Paramagnetic Impurity Atoms

Mon, 04 Sep 2023 00:00:00 +0000

One of the possible ways to obtain silicon with magnetic properties is the introduction of paramagnetic impurities into silicon: Cr, Mn, Fe, Ni, and Co. In our opinion, silicon materials containing magnetic nanosized clusters are most suitable for spintronic devices. The possibility of obtaining silicon with magnetic properties by diffusion doping was studied in this work. To obtain silicon doped with Cr, Mn, Fe and Ni impurity atoms, p-type single-crystal silicon with a specific resistance of ρ = 5 Ohm·cm and ρ = 0.5 Ohm·cm was used, and for doping with Co atoms, n-type silicon with resistivity ρ=10 Ohm·cm was used. The diffusion temperature and time were chosen such that, after diffusion annealing, the samples with impurity Cr, Fe, and Mn atoms remained highly compensated p-type, and when doped with impurity Co atoms, they remained high-resistance n-type. The results of the study showed that with decreasing temperature, the value of the negative magnetoresistance Δρ/ρ in the Si<Mn> samples increases and reaches its maximum value (about 800%) at T = 240 K, a further decrease in temperature leads to a decrease in the magnetoresistance, and at a temperature T = 170 K, the sign of the magnetoresistance is inverted. In Si <Cr> samples, with decreasing temperature, the positive magnetoresistance turns into a negative one, the value of which increases with decreasing temperature, and is achieved at T=100 K Δρ/ρ = 45–50%. In Si<Fe> samples, with decreasing temperature, the value of negative magnetoresistance increases monotonically and at T=100 K its value is Δρ/ρ = (100÷120) %. The study in Si<Сo> samples showed that with decreasing temperature the value of positive magnetoresistance increases and at Т=100 K it reaches Δρ/ρ = (17÷20) %. The study of magnetoresistance in samples - Si<Ni> showed that with decreasing temperature the value of positive magnetoresistance increases and at T=100 K it reaches Δρ/ρ = (10÷15) %. When studying the magnetic properties of p-Si <B, Mn> samples at low temperatures (below T=30 K), a ferromagnetic state was found, i.e. succeeded in obtaining a magnetic semiconductor material by the method of diffusion of a paramagnetic impurity. In the overcompensated Si <B, Mn> (n‑type) samples, no magnetic hysteresis was found. This shows a significant effect on the magnetic properties of the manganese impurity in silicon of its charge and, accordingly, spin state. Based on the results obtained, it can be argued that diffusion doping of silicon with manganese can be used to obtain silicon with magnetic properties.

Effect of the Diffusion of Copper Atoms in Polycrystalline CdTe Films Doped with Pb Atoms

Mon, 04 Sep 2023 00:00:00 +0000

The process of diffusion of labeled copper atoms in p-CdTe<Pb> coarse-block films with a columnar grain structure has been studied. The CdTe<Pb> film is a p-type semiconductor, where an increase in the Pb concentration in the composition of the CdTe films increases the resistivity ρ of the structure. When the Pb concentration in CdTe changes from 10¹⁸ to 5·10¹⁹ cm^-3, the hole concentration decreases by more than 3 orders of magnitude at a constant operating level depth of E_V + (0.4 ± 0.02) eV. This may indicate that the concentration of acceptor defects, which are formed in the films due to self-compensation upon doping with a Pb_Cd donor, exceeds the number of the latter. Electrical measurements by the Hall method were carried out at a direct current and a temperature of 300 K. As a result, an increase in the temperature of films on a Mo-p-CdTe<Pb> substrate during annealing affects the electrical parameter of charge carrier mobility µ, it decreases significantly. X-ray diffraction analysis showed that on the diffraction patterns of samples of p-CdTe<Pb> films, all available reflections correspond to the CdTe phase and up to х = 0.08 do not contain reflections of impurity phases and have a cubic modification. Based on the results of the calculation, it was established that the low values of the diffusion coefficient of Cu atoms are due to the formation of associates of the A type , which are directly dependent on the concentration of atoms. Diffusion length L_n and lifetime τ_n of minority current carriers in large-block p-type cadmium telluride films, which can also be controlled by introducing lead atoms into cadmium telluride.

Investigation of Structural, Optical and Electrical Properties of MnO Doped with Cu Thin Films Prepared by PLD Technique for Solar Cell Applications

Doaa T. Mohammed, Ghuson H. Mohammed — Mon, 04 Sep 2023 00:00:00 +0000

In the current study, concentrated Nd:YAG laser pulses at 500 mJ with a second radiation at 1064 nm (pulse width 9 ns) and repetition frequency (6 Hz) for 300 laser pulses incident on the target surface were employed to coat glass substrates with MnO thin films. Using an X-ray diffractometer (XRD), an atomic force microscope (AFM), and a UV-Vis spectrophotometer, the structural, morphological, and optical characteristics of the films doped with different concentrations of Cu content (0.03, 0.05, 0.07, and 0.09) were examined. The results show that the films are polycrystalline, with the largest peak appearing at an angle of 35.31, or a reflection of (111). The crystalline size of the deposited thin films was calculated using Debye Scherer formula and found to increase from 11.8 nm for undoped MnO₂ to 29.6 nm for doped (MnO) with the increase of Cu content from x=0 to x=0.09 at preferred orientation of (111). All the samples have a cubic structure. Also, the results showed that Cu content of the films affects the surface morphology. From the results of AFM analysis, it was found that the roughness and average diameter change when adding Cu to the structure, with the highest value occurring at Cu ratio 0.09 equal to 65.40 and 71.21 nm, respectively. UV–Vis spectrophotometer was used to investigate the optical transmission. It was found that when Cu content of films increased, the transmittance of films decreased. Hall Effect measurements show that all prepared films at RT have two type of conductivity P-type and n-type. The electrical characteristics of the (MnO)_1-xCu_x/Si heterojunction Solar Cell have been studied and found that the efficiency (η) decreases with the increase of Cu content.

Mechanisms of Current Transition in High Compensated Silicon Samples with Zinc Nanoclusters

Eshkuvat U. Arzikulov, M. Radzhabova, Sh.J. Quvondiqov, G. Gulyamov — Mon, 04 Sep 2023 00:00:00 +0000

This article presents experimental results on the study of the current-voltage characteristics of strongly compensated n- and p-type silicon samples diffusion-doped with zinc at a temperature of 80 K. The current-voltage characteristics of the studied samples contain both sublinear and superlinear sections. Several (up to eight) characteristic areas were found, the number of which depends on the degree of illumination, temperature, and electrical resistivity of the sample. Under certain conditions, there is an alternation of sections of the current-voltage characteristic with negative differential conductivity of the N- and S-type, behind which current instabilities with an infra-low frequency are observed. The appearance of sections of the current-voltage characteristic with a quadratic dependence is explained by the presence of fast and slow recombination centers associated with zinc nanoclusters, and sublinear sections are explained in terms of the theory of the "injection depletion effect". The formation of nanoclusters with the participation of zinc ions was confirmed by atomic force microscopy studies.

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

Iuliia Riabenko, Sergey Shulga, Nikolai А. Makarovskii, Konstantin Beloshenko — Mon, 04 Sep 2023 00:00:00 +0000

The article is focused on optical properties of nanostructures containing spherical gold nanoparticles of various radii. We explore correlation between the particle radius and the choice of permittivity model applied to describe optical absorption spectra of gold granules. The experiments show splitting of the absorption band of granular gold films to form a second absorption peak. The first peak is associated with the phenomenon of plasmon resonance, while the second one reflects quantum hybridization of energy levels in gold. Quantum effects are shown to prevail over size effects at a granule diameter of about 5-6 nm. The Mie theory gives a rigorous solution for the scattered electromagnetic field on a sphere taking into account optical properties of the latter, however, it does not specify the criteria for selecting a model to calculate dielectric permittivity. Both calculations and experiments confirm the limiting diameter of gold nanoparticles where the Hampe-Shklyarevsky model is applied. Meanwhile, this model is still unable to predict the splitting of the plasma absorption band. The data presented in the article can be used for a predetermined local field enhancement in composite media consisting of a biolayer and metal nanoparticles. The conducted research provides a deeper understanding of the influence of a terahertz high-intensity electromagnetic field localized in the space on quantum dots.

Ab-Initio Study of Structural, Electronic and Optical Properties of ZnX (X = Te, S and O): Application to Photovoltaic Solar Cells

Mon, 04 Sep 2023 00:00:00 +0000

The purpose of this research is to investigate the structural, electronic, and optical properties of ZnX compounds, particularly those with X = Te, S, and O, which have direct bandgaps that make them optically active. To gain a better understanding of these compounds and their related properties, we conducted detailed calculations using density functional theory (DFT) and the CASTEP program, which uses the generalized gradient approximation (GGA) to estimate the cross-correlation function. Our results for lattice modulus, energy bandgap, and optical parameters are consistent with both experimental data and theoretical predictions. The energy bandgap for all compounds is relatively large due to an increase in s-states in the valence band. Our findings suggest that the optical transition between (O - S - Te) - p states in the highest valence band and (Zn - S - O) - s states in the lowest conduction band is shifted to the lower energy band. Therefore, ZnX compounds (X = Te, S and O) are a promising option for optoelectronic device applications, such as solar cell materials.

Mean Lifetimes of ns, np, nd, & nf Levels of N V

Rizwana Siddique, Roohi Zafar, Salman Raza, S.M. Zeeshan Iqbal, Zaheer Uddin — Mon, 04 Sep 2023 00:00:00 +0000

Nitrogen is one of the key elements in the evolution and formation of stellar objects. Earth's atmosphere contains 21% oxygen and 78% nitrogen; these two gases give rise to aurora when ions of the solar wind in the ionosphere collide with them. Some aerosols made of nitrogen and oxygen are also found in the atmosphere. Nitrogen, hydrogen, carbon, and oxygen are the main contributors to the origin of life on Earth. The spectrum of nitrogen ion (N V) has been studied using Quantum defect theory (QDT) and Numerical Coulombic approximation (NCA). N V has two electrons in the core, with the nucleus, and one electron outside the core. It makes it hydrogen or lithium-like. In the first part, the energies of the ns, np, nd, and nf up to n < 30 were calculated with the help of QDT. In the second part, the wavelengths were calculated using the energies and line strength parameters using NCA. Very little experimental data on lifetime and transition probability are available; however, Biemont et al. have calculated the lifetime of the 48 levels of N V using coulomb approximation. In this study, we calculated the lifetime of 196 multiplets of N V. The results are compared with the available experimental and theoretical lifetimes; an excellent agreement was found between known lifetimes and calculated in this work. The lifetimes of 100 multiplets are presented for the first time. The lifetimes of each of the Rydberg series of N V were fitted, and a third-degree polynomial represents the lifetimes of each series.

Investigation of Defect Formation in Silicon Doped with Silver and Gadolinium Impurities by Raman Scattering Spectroscopy

Mon, 04 Sep 2023 00:00:00 +0000

Silicon doped with gadolinium and silver impurities were studied using a Renishaw InVia Raman spectrometer. Registration and identification of both crystalline and amorphous phase components in the samples was carried out. Some changes are observed in the Raman spectra of gadolinium-doped silicon samples compared to the initial sample. It has been experimentally found that an increase in the silver impurity concentration in gadolinium-doped silicon leads to a smoothing of the Raman spectrum, which indicates the formation of a more perfect crystal structure.

Isolation of Responsive Elements of Planar Multi-Element Photodiodes

Mykola S. Kukurudziak — Mon, 04 Sep 2023 00:00:00 +0000

In the mass production of multi-element silicon p-i-n photodiodes, the problem of systematic rejection of products due to a decrease in the insulation resistance between the active elements of photodetectors has been revealed. The purpose of this work is to study the causes of insulation resistance degradation and to establish optimal methods for avoiding this phenomenon. A comparative analysis of three insulation methods was carried out: classical insulation by the surface of a non-conductive substrate and a dielectric layer; insulation by means of mesaprofile grooves with a dielectric film; insulation by means of areas of limitation of surface leakage channels isotypic with the substrate material (in this case, p⁺-type) formed in the gaps between active elements. The study found that the reason for the deterioration of the insulation resistance between the active elements of photodiodes is the presence of conductive inversion channels at the Si-SiO₂ interface due to the use of silicon with high resistivity. One mechanism for the formation of inversion channels is the redistribution of impurities in the masking oxide (in particular, phosphorus) and their diffusion to the interface during thermal operations. Another mechanism for the formation of inversion layers is the diffusion of boron from silicon into SiO₂ during heat treatment due to the fact that the boron segregation coefficient is less than one. In the manufacture of samples with insulation using non-conductive areas of the substrate, a decrease in insulation resistance was observed as the technological route was performed (after each subsequent operation, the resistance degraded). The degree of degradation can be reduced by reducing the duration of thermal operations. It has been shown that reducing the thickness of the masking oxide causes a decrease in insulation resistance. When using mesa-technology, it is possible to increase the insulation resistance by eliminating the high-temperature oxidation operation and, in fact, due to the absence of a masking coating during phosphorus deposition. Insulation by means of ^p+-type areas in the gaps between the active elements allows to obtain the highest insulation resistance values. The formation of these regions with a width of 100 μm in the gaps with a width of 200 μm allowed us to obtain an insulation resistance of 25-30 MΩ. To ensure the insulation of the active elements of photodiodes by this method, two thermal operations are added to the technological route. The number of thermal operations can be reduced by doping the entire silicon surface with a low boron concentration before forming a masking coating.

Unsteady Flow Past an Accelerated Vertical Plate with Variable Temperature in Presence of Thermal Stratification and Chemical Reaction

Nitul Kalita, Rudra Kanta Deka, Rupam Shankar Nath — Mon, 04 Sep 2023 00:00:00 +0000

This work aims to investigate the effect of thermal stratification on fluid flow past an accelerated vertical plate in the presence of first order chemical reaction. The dimensionless unsteady coupled linear governing equations are solved by Laplace transform technique for the case when the Prandtl number is unity. The important conclusions made in this study the effect of thermal stratification is compared with the scenario in which there was no stratification. The results of numerical computations for different sets of physical parameters, such as velocity, temperature, concentration, skinfriction, Nusselt number and Sherwood number are displayed graphically. It is shown that the steady state is attained more quickly when the flow is stratified.

Multiparameter Control of Energy Characteristics of Waveguide-Cavity Resonator-Slot Radiators

Natalya K. Blinova, Mikhail V. Nesterenko, Viktor A. Katrich — Mon, 04 Sep 2023 00:00:00 +0000

The problem of connecting three electrodynamic volumes with ideally conducting walls through electrically narrow rectilinear connecting slots and a radiating slot is solved by the generalized method of induced magnetomotive forces (MMF). The solution is obtained in an analytical form, taking into account the finite thickness of the walls of the connected volumes. The volumes are an infinite rectangular waveguide excited by a fundamental wave, a rectangular cavity resonator, and a half-space above an infinite plane. The energy characteristics of this system have been comprehensively studied depending on the geometric parameters of the constituent elements of the structure under consideration.

Dosimetric Evaluation Study of 10-MV FFF Used in SBRT for Lung Tumours

Mohamed I. Soliman, Wahib M. Attia, Khaled M. Elshahat — Mon, 04 Sep 2023 00:00:00 +0000

Purpose: The objective of this research was to conduct a comparative and dosimetric analysis of three different radiotherapy techniques used in lung stereotactic body radiotherapy (SBRT), the three-dimensional conformal radiotherapy (3DCRT), intensity-modulated radiation therapy (IMRT), and volumetric modulated arc therapy (VMAT), using a 10 MV flattening filter-free (FFF) photon beam. Materials and methods: The present study employed computed tomography (CT) images of a humanoid phantom for the purpose of treatment planning. The gross tumour volumes (GTVs) delineated in both the central and peripheral positions of the lungs. The determination of Planning Target Volumes (PTVs) involved the addition of a margin of 0.5 cm to the Gross Tumour Volume (GTV). Three-dimensional conformal radiotherapy (3DCRT), intensity-modulated radiation therapy (IMRT), and volumetric modulated arc therapy (VMAT) treatment plans produced employing a 10-megavolt (MV) flattening filter-free (FFF) photon beam. The calculation of dosage for all plans Performed using the anisotropic analytical algorithm (AAA). Results: IMRT and VMAT had better PTV dose conformation than 3DCRT for both central and peripheral targets. PTV conformity improved in VMAT compared to IMRT, and CI values were acceptable for VMAT, IMRT, and 3DCRT plans. VMAT plans had slightly better CI than IMRT, with better results in peripheral lung PTVs compared to central PTVs. VMAT and IMRT are superior for treating HDV and D2cm, with lower HDV for peripheral lung tumours. Both 3DCRT and IMRT improved outcomes for peripheral lung PTVs, while VMAT was better for central lung PTVs. The former proved better with less low lung doses and improved D2cm results. 3DCRT plans demonstrated higher precision in dose distribution than VMAT and IMRT plans, with superior average GI values. VMAT and IMRT had higher HI, Dmax, and D2% than 3DCRT. VMAT plans compared to IMRT plans, with similar HI values for central lung PTVs. VMAT better spares OARs than other techniques, but V20 and V30 lung doses were lower with 3DCRT. VMAT increases lung dose, but OAR stays below thresholds.

Conclusion: The investigation found that all three treatment techniques can deliver SBRT plans that meet RTOG dose constraints. However, VMAT is a better treatment strategy than IMRT and 3DCRT for both peripheral and central lung PTVs, based on dosimetric indices like CI, D2cm, HI, and HDV. The study found that 3DCRT improves dosimetric indices, especially gradient index (GI), more than VMAT. Despite the need for more monitor units (MUs) in VMAT plans, treatment time reduced due to faster gantry velocity and higher dose rates (2400cGy/min) via free flatting filter energy.

Exploring the Impact of Lipid Domain Size on the Lifetime: A Dissipative Particle Dynamics Study

Kan Sornbundit — Mon, 04 Sep 2023 00:00:00 +0000

In this research, we have used the dissipative particle dynamics (DPD), a mesoscopic simulation technique, in order to investigate the dynamics of lipid domains in near critical temperature. Our specific focus has been on exploring the influence of lipid domain size on its lifetime, which mimics the behavior of lipid rafts within cellular membranes. The lipid membranes used in this study were composed of saturated and unsaturated lipids, which have been immersed in water. Through the simulation of these membranes close to their critical temperature, we have successfully generated fluctuating domains that mimic the lipid rafts observed in cellular systems. We have proposed a method to obtain the lifetime of the fluctuating domains by analyzing the sizes of the lipid domains at specific intervals of time. Our investigations have revealed a linear correlation between the initial size of the lipid domain and its lifetime. Our research finding give an insight into the underlying mechanisms that govern lipid rafts and their vital role in various cellular processes.

Effects of Radiation and Heat Dissipation on MHD Convective Flow in Presence of Heat Sink

Salma Akhtar, Keshab Borah, Shyamanta Chakraborty — Mon, 04 Sep 2023 00:00:00 +0000

The paper examines heat and mass transfer in MHD convective flow across a vertical porous plate in presence of radiation, heat sink, and dissipation of heat. A strong magnetic field is applied perpendicular to the plate and directed into the fluid area. The governing non-dimensional equations are solved using MATLAB built-in bvp4c solver technique. With the use of mathematical software, the findings are computed, and the effect of the various non-dimensional parameters entering into the problem on the velocity, temperature and concentration profiles are displayed in graphical formats. It has been noted that the application of the magnetic field slows down fluid velocity. Additionally, both the thermal radiation effect and the Prandtl number are fully applicable to the fluid temperature. It is significant to notice that the heat sink dramatically reduces fluid temperature and fluid velocity. The current work is utilized in many real life applications, such as chemical engineering, industrial processes, a system may contain multiple components, each of whose concentrations varies from one point to the next in a number of different circumstances.

Prediction of Viscosity of Cobalt Ferrite/SAE50 Engine Oil based Nanofluids using well Trained Artificial Neutral Network (ANN) and Response Surface Methodology (RSM)

Mon, 04 Sep 2023 00:00:00 +0000

Heat transmission by ordinary fluids such as pure water, oil, and ethylene glycol is inefficient due to their low viscosity. To boost the efficiency of conventional fluids, very small percent of nanoparticles are added to the base fluids to prepare nanofluid. The impact of changing in viscosity can be used to investigate the rheological properties of nanofluids. In this paper, (CoFe₂O₄)/engine oil based nanofluids were prepared using two steps standard methodology. In first step, CoFe₂O₄ (CF) were synthesized using the sol-gel wet chemical process. The crystalline structure and morphology were confirmed using X-Ray diffraction analysis (XRD) and scanning electron microscopy (SEM), respectively. In second step, the standard procedure was adapted by taking several solid volume fractions of CF as Ø = 0, 0.25, 0.50, 0.75, and 1.0 %. Such percent of concentrations were dispersed in appropriate volume of engine oil using the ultrasonication for 5 h. After date, the viscosity of prepared five different nanofluids were determined at temperatures ranging from 40 to 80 °C. According to the findings, the viscosity of nanofluids (µ_nf) decreased as temperature increased while increased when the volume percentage of nanofluids Ø raised. Furthermore, total 25 experimental observations were considered to predict viscosity using an artificial neural network (ANN) and response surface methodology (RSM). The algorithm for building the ideal ANN architecture has been recommended in order to predict the fluid velocity of the CF/SAE-50 oil based nanofluid using MATLAB software. In order to determine the correctness of the predicted model, the mean square error (MSE) was calculated 0.0136.

Spectra of Multiply Charged Ions in Laser Plasma Formed from Gas-Containing Targets

Mon, 04 Sep 2023 00:00:00 +0000

The paper presents the results of a study of the charge and energy characteristics of multiply charged ions excited on the surface of a single-element and hydrogen-containing multi-component element targets under the influence of laser radiation with a power density (q=10⁸-10¹² W/cm²). It has been experimentally shown that, for all used values of q laser radiation, laser-induced plasma from gas-containing targets is characterized by a lower relative yield (dN/dE) of multi-charged ions with a charge number of Z>+3, compared to the plasma produced on the surface of the single element target. Moreover, the tendency to reduce dN/dE of multi-charged ions of the multi-element target, in comparison with the relative yield of ions from the plasma of the single-element target, is more significant and it depends on the charge of the excited ions. The increase in the charge and energy state, duration, and yield of ions of the heavy component, which occurs with an increase in the content of the light component in the target, has been established. This is explained by a decrease in the efficiency of recombination processes caused by an increase in the expansion velocity of a plasma plume due to a decrease in its average mass.

Effectiveness of Wavelet Denoising on Secondary Ion Mass Spectrometry Signals

Nadia Dahraoui, M'hamed Boulakroune, S. Khelfaoui, S. Kherroubi, Yamina Benkrima — Mon, 04 Sep 2023 00:00:00 +0000

Wavelet theory has already achieved huge success. For Secondary Ions Mass Spectrometry (SIMS) signals, denoising the secondary signal, which is altered by the measurement, is considered that an essential step prior to applying such a signal processing technique that aims enhance the SIMS signals.The most efficient and widely used wavelet denoising method is based on wavelet coefficient thresholding. This process involves three important steps; wavelet decomposition: the input signals are decomposed into wavelet coefficients, thresholding: the wavelet coefficients are modified according to a threshold, and reconstruction: the modified coefficients are used in an inverse transform to obtain the noise-free-signal. Several researchers have used thresholding wavelet denoising techniques.

The choice of wavelet type and the level of resolution can have a significant influence; it is important to note that the choice of resolution level depends on the type of signal we are dealing with, the nature of the present noise, and our specific goals for the denoised signal. It is generally recommended to test different resolution levels and evaluate their impact on the quality of the denoised signal before making a final decision. Moreover, the results obtained in wavelet denoising can be significantly influenced by the selection of wavelet types. The chosen wavelet type plays a crucial role in the extraction of signal details. Indeed, the effectiveness of denoising the MD6 sample has been demonstrated by the results obtained with sym4, db8, Haar and coif5 wavelets? These wavelets have effectively reduced noise while preserving crucial signal information, leading to an enhancement in the quality of the denoised signal.

Effect of GeO2 Dopants in FBG Sensor Performance for Temperature and Strain

Wasmaa A. Jabbar, Ayser Hemed, Mayyadah Fadhala, Ismaeel Al-Baidhany — Mon, 04 Sep 2023 00:00:00 +0000

In this simulation study, the response of fiber Bragg grating (FBG) sensors is investigated and optimized. Uniform and nonuniform FBG spectra with new component are suggested by fine selection with (COMSUL program) and compared theoretically under the effect of several external strain values (0.005, 0.006, 0.007, 0.008, 0.009 and 0.01). These two types operation have been examined by the Optisystem programmer. The measured sensitivity was based on VCSEL laser source with operation wavelengths of 1650, 1600, and 1550 nm via non-uniform and uniform configuration. The achieved sensitivity was found to have different values; 5.7, 2.6, and 1.77, while the highest observed sensitivity value is recorded at a wavelength of 1550 nm. Accordingly, this wavelength was chosen to advance the study. Temperatures of 20, 30, 40, 50, and 60 degrees Celsius were applied. Measured sensitivity between them varied, and satisfied the following functions: sine, Gauss, and Boltzmann indicating altering in sensor responses.

Characterization Study of Double Filtered Sensor Length Effect on Strain Sensitivity

Wasmaa A. Jabbar, Ayser Hemed, Mayyadah Fadhala, Ismaeel Al-Baidhany — Mon, 04 Sep 2023 00:00:00 +0000

In this simulation study, Optisystem 18 software is used to monitor and study the effectiveness of side strain on selected lengths of two virtual uniform fiber Bragg grating (FBG) sensors. The operational FBG sensor Bragg wavelength was 1550 nm, which is used to find the measured shift in deflected light source optical spectrum. This value is also supplied by the light source to offer the minimum absorption and attenuation during transmission inside the optical fiber. Reliability of the sensor and technique of transferring the signal under such effect are screened. The investigator is also used to observe the shift in wavelength with altered applied side strain. The influence of sensor active length on side strain sensitivity is studied where according to theory, the length of the FBG influences the sensitivity via reflectivity . The constructed sensor sensitivity is observed against length before and during the experiment. The sensing principle, in essence, depends on tracking the wavelength shift due to the variation of such strain. Results achieved in this study show an inverse relationship between sensor effective length and shift in the observed wavelength. The measured strain sensitivity is carried out for the active sensor length, which ranges from 0.05 to 15 cm, with corresponding sensitivity values of 1.19 pm/^OC to 0.9 pm/^OC, respectively, under the same strain conditions. The empirical results also show the success of the suggested sensing system in measuring strain. The strain measurement, ε, is linearly increasing, identical to the increasing values of the wavelength shift of Bragg. It's also been observed that the wavelength of Bragg is shifting during small ratios in the length protraction of the FBGs.

Investigating the Impact of Varying Quantities of TiO2 Nanoparticles on the Anti-Corrosive Characteristics of TiO2-Epoxy Nanocomposite Coatings

Ahmed Ibrahim Dawood, Ahmed Qasim Abdullah — Mon, 04 Sep 2023 00:00:00 +0000

Prepared were pills coated with TiO₂-epoxy nanocomposites, and their anti-corrosive properties were studied by examining the impact of varying amounts of TiO₂ nanoparticles in the epoxy resin. The anti-corrosive characteristics of pills were investigated employing electrochemical impedance spectroscopy (EIS). Based on the EIS results, the sample containing 0.01 mg of TiO₂ demonstrated the highest impedance value, indicating superior corrosion resistance and better anti-corrosion properties than the other samples. Also, this sample has the lowest corrosion current density among the all samples, with a value of 1.329E-07 mA/cm², which shows that this sample has the best corrosion resistance and a slower rate of corrosion compared to the other samples.

The Effect of Multi-Wall Carbon Nanotubes Addition on the Shielding Properties Against Gamma Radiation

Moaz Altarawneh, Mutaz Aladailaha, Osama Al-Madanat — Mon, 04 Sep 2023 00:00:00 +0000

In this work, the effect of Multi-Wall Carbon Nanotubes (MWCNTs) addition on the materials shielding properties against Gamma radiation with an energy of 662 keV from a ¹³⁷Cs source is investigated. The linear attenuation coefficient of MWCNTs-based materials (gelatin-water mixture) with MWCNTs concentrations of 0%, 5%, and 10% is measured. To isolate the contribution of the MWCNTs unique structure to the shielding capabilities, samples with the same concentrations of activated carbon were fabricated and their linear attenuation coefficients were obtained. Also, the linear and the mass attenuation coefficients are obtained theoretically for the same concentrations using the XCOM program and compared with measured values. It is found that the addition of MWCNTs by 5% or 10% has increased the linear attenuation coefficient by around 5% when compared to the same concentrations of activated carbon. This increase in the shielding apabilities against gamma radiation can be related to the interaction of gamma radiation with the extraordinary geometry and structure of MWCNTs.

Comprehensive Investigation of Neolithic Ceramic Samples: Firing Technology and Age Insights

Sahib Mammadov, Aybeniz Ahadova — Mon, 04 Sep 2023 00:00:00 +0000

Thermogravimetric (TG/DTG), thermoluminescence (TL), and X-ray powder diffraction (XRD) techniques were applied to characterize samples collected from the archaeological site of Polutepe in Azerbaijan, dating to the Neolithic period, and gave new information on the firing technology. The thermogravimetric analysis of ceramic shards from Polutepe revealed that the firing temperature of the samples was in the range of 700°C, based on the presence of calcite in the sample. XRD analysis confirmed the presence of quartz, feldspar, and clay minerals in the ceramic samples. According to XTD analysis the mineral composition of the ceramic sample from Polutepe site was as follows: Quartz-33.8 mass%, Feldspar (albite)-21.7 mass%, Muscovite- 33.6 mass%, and Calcite- 10.9 mass%.

TL glow-curve intensity at 325°C was measured to estimate the historical dose of the sample, which was found to be 22.19±1.36 Gy. The concentration of U, Th, and K were 2.24±0.20 ppm , 8.31±0.80 ppm, 2.39±0.23% respectively. Dose rate and age calculation were conducted using the DRAC, version 1.2 and output results are as follows: Environmental dose rate: 3.46±0.19 mGy/a; Age of the sample: 4.400±530 BC years which are in line with the stratigraphically estimated age of this area and with the radiocarbon age (4270±160 BC) reported in our previous work. The results obtained from this multidisciplinary approach provide insights into the firing technology and age of the ceramic samples.

Advancements in Thermoluminescence Dating: A Case Study of Medieval Brick Structures in Azerbaijan

Sahib Mammadov, Aqshin Abishov — Mon, 04 Sep 2023 00:00:00 +0000

The study aimed to improve the precision of dating historical landmarks, specifically the Ballabur castle in Lenkaran, Azerbaijan Republic, using the thermoluminescence dating (TL) method. The annual dose rate, calculated with a -spectrometer equipped with a hyper-pure germanium detector, was found to be 2.98±0.19 mGy/year. By employing an online dose rate and age calculator, the sample's age was determined to be 920±50 years, consistent with the historical estimates of this region.

Influence of Lead Nanoparticles on Structural, Morphological, and Mechanical Characteristics of (SiR-PU/Micro-Pb) Composites and Radiation Shielding Applications

Mousa Hawan Naeem, Sameer Hassan Hadi Al-Nesrawy, Mohammed H. Al-Maamori — Mon, 04 Sep 2023 00:00:00 +0000

This research includes the manufacture of a polymeric nanocomposite consisting of silicone rubber/polyurethane as a base, with the addition of the first filler of micro-lead with a ratio of 300 pphr and the second filler of nano-lead with different ratios (0, 0.2, 0.4, 0.6, 0.8 pphr). With the addition of hexane (liquid state) to the superposition using the casting technique at room temperature. The structural properties of the surfaces of the samples were measured using Fourier transformation spectroscopy (FT-IR) and the scanning electron microscope (SEM). In addition to studying the mechanical properties represented by each hardness, tensile, elongation, and elastic modulus. (FT-IR) showed the absence of a chemical reaction for all samples. While SEM measurements showed a homogeneous distribution of micro-lead and nano-lead in the presence of hexane equally, and there were no voids in the eyes of the prepared rubber equally. For the mechanical properties, we see that the hardness, tensile strength and modulus of elasticity continue to improve with the increase in the number of lead nanoparticles. And a decrease in elongation as a result of inverse proportion to the modulus of elasticity. From the results obtained, this composite can be used in gamma ray attenuation applications in shielding, especially in medical and industrial fields.

Enhancements of Structural and Optical Properties of MgO: SnO2 Nanostructure Films

R.H. Ayoub, Muhammad H. AL-Timimi, M.Z. Abdullah — Mon, 04 Sep 2023 00:00:00 +0000

This study investigates the structural and optical properties of MgO:SnO2 nanoparticles using the Chemical precipitation method, The thin films were deposited by the spin coating technique on glass substrates. X-ray diffraction analysis proved the crystalline structure of prepared thin films, with the peaks corresponding to the (110), (101), (200), (211), and (220) planes, with the tetragonal SnO2 crystal structure, Fourier transforms infrared (FTIR), and scanning electron microscope (SEM) used to characterize the functional groups, shape, and dimensions of synthesized metal oxide nanoparticles. The optical properties of the films were studied by UV-Vis spectroscopy, and the bandgap energy was estimated to be in the range of (3.9 - 3.4 eV). The refractive index and extinction coefficient of the films were also determined, and the results indicated that the films had good transparency in the visible region, The study concludes that MgO:SnO2 thin films obtained by spin coating technique have potential applications in optoelectronics and gas sensors.

SCAPS Numerical Analysis of Graphene Oxide /TiO2 Bulk Heterojunction Solar Cell Sensitized byN719 Ruthenium Dye

Hmoud Al Dmour — Mon, 04 Sep 2023 00:00:00 +0000

Solid-state dye-sensitized solar cells (SSDSC) have been fabricated using two different metal oxide materials, graphene oxide and titanium oxide, are used as hole and electron transport materials, respectively. The N719 dye ruthenium between the hole and electron transport materials to act as an absorber layer in your Go/N719dye/TiO2 solar cells. Through the SCAPS-1D simulation, it was found that the Go/N719dye/TiO2 solar cells have significantly improved the performance of the solar cells compared to the Go/TiO2 solar cells. Specifically, the short circuit current (Jsc) has increased from 0.17 mA/cm²to 1 mA/cm², the open circuit voltage (Voc) has increased from 0.2 V to 1 V, and the power conversion efficiency (η) has increased from 0.02% to 2.5%. Additionally, Various factors that can affect the performance of Go/N719 dye/TiO2 solar cells. It was found that the optimal dye thickness for achieving high short circuit current density, high power conversion efficiency, and high open circuit voltage is between 200nm and 300nm. Furthermore, the operating temperature of the solar cells also affects their performance. Increasing the operating temperature negatively affects the open circuit voltage and power conversion efficiency of the cells, while the short circuit current density is slightly enhanced. Finally, the efficiency of a solar cell can be affected by the type of metal used for the electrode and the type of semiconductor material used in the cell. In Ni and Cu electrodes solar cells ohmic contacts allow for efficient transfer of electrons, whereas Schottky barriers can impede electron flow and reduce efficiency in Mo and Ag electrodes solar cells .

Nucleon-Nucleon Elastic Scattering for Motion in The Shifted Deng-Fan Potential

Bidhan Khirali, S. Laha, Biswanath Swain, Ujjwal Laha — Mon, 04 Sep 2023 00:00:00 +0000

The scattering theory's main objective is to comprehend an object by hurling something at it. One can learn details about an object by observing how it bounces off other objects. The potential that exists between the two particles is the thing that one seeks to comprehend. In time-independent approach to scattering, one assumes that the incident beam has been activated for a very long time and that the entire system is in a stationary state. For short-range local potentials, the variable phase methodology is highly useful in solving quantum mechanical scattering problems. Variable phase methodology/phase-function technique has been explicitly utilized for non-relativistic nucleon-nucleon scattering phenomenon with the fundamental central local potential term and without spin-orbit force. Working under this methodology, scattering phase shifts, total scattering cross section and Differential cross section have been investigated for a new nuclear potential model “Shifted Deng-Fan potential”. Real nucleon-nucleon scattering systems (n-p) and (p-p) have been treated for this purpose with partial waves up to l = 2 in the low and moderate energy region. For l > 0 waves, interacting repulsive barrier potential has been incorporated with the existing central part. Our results for the considered potential model show a close contest with that of the experimental data.

Model of Radiation-Induced Motion of Liquid Inclusions in Crystal

Mon, 04 Sep 2023 00:00:00 +0000

A physical model is formulated for the motion of liquid inclusions in a crystal in the field of forces caused by the presence of radiation point defects. The model is based on a statistical approach to the processes of induced transitions of structural elements of a crystalline matrix at the interfacial boundary with its solution. From the energy principle, an analytical dependence of the velocity of a spherical azimuthally symmetric inclusion on its size is obtained, considering the threshold nature of the motion. It is shown that the theoretical dependence correlates well with experimental results obtained for inclusions of aqueous saturated solution in potassium chloride crystals irradiated by high-energy electrons. The proposed model of the radiation-induced motion of a liquid inclusion is dynamic and allows us to interpret the nature of inclusion velocity changes in the crystal over time to determine the characteristic energy parameters of point defects.

Amplitudes of 3H, 3He Two-Particle Photo-Breakup in Non-Local QED Approach

Pylyp Kuznietsov, Yuriy A. Kasatkin, Vyacheslav F. Klepikov — Mon, 04 Sep 2023 00:00:00 +0000

Three-nucleon systems are essential for the investigation of many-body forces in nuclear physics. Well-grounded parametrization of their vertex functions with further application for the calculation of cross-sections in nonlocal QED approach provides the ground for investigation of the variety of multi-particle systems. In present paper we describe the process of parametrization of two-particle photo-breakup amplitudes of three-nucleon systems (³H, ³He). We provide the general description of the wave function construction for three-nucleon systems as well as the parametrization of their vertex functions accounting two- and three-nucleon interactions based on meson exchange current formalism. In our calculations we account first and second order one-pion exchange terms and the term related to the exchange of ω and ρ mesons. The three-nucleon interaction potential is given as a sum of attraction (two-pion exchange) term and
appropriate repulsive part. Based on the variational ”Urbana + Model VII” amplitudes we provide the results for energy dependence of differential cross-section of ³He(γ, p)d reaction at proton angle θ = 90◦ from the threshold up to E_γ = 40 MeV and compare theoretical predictions with the available experimental data. The investigation is also provided for angular cross-section distributions at high photon energies (E_γ = 305 ± 5 MeV; 365 ± 5 MeV; 450 ± 10 MeV and 675 ± 50 MeV). Correct description of ³H, ³He photo-disintegration processes in a unified approach based on the gauge nature of the electromagnetic field implies application of this model for other multi-particle systems.

Multiple Ligand Simultaneous Docking of Antiviral Drugs and Cyanine Dyes with Proteins

Mon, 04 Sep 2023 00:00:00 +0000

Protein nanoparticles are currently regarded as promising biocompatible and biodegradable systems for targeted delivery of different types of pharmacological agents. Prior to fabricating such kind of drug nanocarriers it is reasonable to evaluate the drug-protein binding affinity and possible interaction modes using the computational tools, particularly, the molecular docking technique. The present study was undertaken to evaluate the possibility of creating the protein nanoparticles carrying the antiviral drugs and cyanine dyes as visualizing agents. The components of the examined systems included endogenous functional proteins cytochrome c, serum albumin, lysozyme and insulin, antiviral drugs favipiravir, molnupiravir, nirmatrelvir and ritonavir, mono- and heptamethinecyanine dyes. Using the multiple ligand simultaneous docking technique, it was demonstrated that: i) the drugs and the dyes occupy different binding sites on the protein molecule and do not interfere with each other; ii) the heptamethines AK7-5 and AK7-6 possess the highest affinity for the proteins; iii) among the examined systems the strongest complexes are formed between the heptamethine dyes and serum albumin. Taken together, the results obtained indicate that albumin-based nanoparticles functionalized by the heptamethine cyanine dyes can be used for targeted delivery of the explored antiviral agents.

Chaos Synchronization of InGaAsP Lasers

Mohammed H.H. Al-Jassani, Aqeel I. Faris, Hussein H. Khudhur — Mon, 04 Sep 2023 00:00:00 +0000

The optical output of a semiconductor laser can fluctuate chaotically by modulating its direct current in limited conditions of the modulated current signal parameters in terms of modulation frequency and modulation index. In this work, single, double, and chaotic pulses of an InGaAsP laser with direct current modulation, are numerically presented through a bifurcation diagram. Numerically, the unidirectional optical coupling system realizes chaotic synchronization between two identical InGaAsP lasers with direct current modulation, as the transmitter/receiver configuration. The transmission time for transmitting light from the transmitted laser to the received laser is essential for controlling the quality of chaos synchronization. The transmission time applies on the order of nanoseconds. Chaos synchronization quality is estimated by a correlation plot and calculated by the cross-correlation coefficient. This study observed the best synchronization quality (complete chaos synchronization) when the two lasers are identical. On the other hand, the chaotic synchronization between two non-identical InGaAsP lasers was investigated. In this case, complete chaos synchronization is not found, and the quality of chaotic synchronization was observed to decrease as the mismatch between the parameters of the two lasers increased.

To Study the Cadmium Sulphide Thin Films Synthesis by Simple Spin Coating Method for Energy Application

Jagmohan Lal Sharma, S.K. Jain, Balram Tripathi, Mahesh Chandra Mishra — Mon, 04 Sep 2023 00:00:00 +0000

The paper examines the properties of CdS thin film, which is used for window material of solar cells and optical devices. The cadmium sulfide (CdS) thin film was prepared by sol-gel method on glass and ITO substrate. Prepared thin film dried in a vacuum oven at 70℃. Thin film and powder of CdS characterized for structural, optical, and electrical properties by X-ray Diffractometer (XRD), UV-Visible spectrometer, and Keithley spectrometer. The average crystallite sizes, microstrain, and dislocation density of the samples were calculated by the Debye Scherrer formula. The optical band gap of CdS calculated by the Tauc-plot method and obtained 2.40 and 2.41eV for powder and film. The absorption wavelength of CdS is suddenly decreased near 280nm and becomes flat in the higher wavelength region. The FTIR spectrometer is used to identification of unknown materials and bond formation. The bond formation, imperfections, and impurities were observed by the PL spectrometer. Keithley spectrometer is used for I-V characteristics and calculates electrical resistivity by Ohms law.

The Effect of Plasma Activation of Reactive Gas in Reactive Magnetron Sputtering

Stanislav V. Dudin, Stanislav D. Yakovin, Aleksandr V. Zykov — Mon, 04 Sep 2023 00:00:00 +0000

The effect of plasma activation of reactive gas on the process of reactive magnetron synthesis of oxide coatings was theoretically and experimentally investigated using a radio-frequency inductively coupled plasma source, which creates a flow of activated reactive gas directed towards the surface on which the oxide coating is deposited. The reactive gas passes through a dense inductively coupled plasma located inside the plasma source, while argon is supplied through a separate channel near the magnetron. A theoretical model has been built allowing the calculation of spatial distributions of fluxes of metal atoms and molecules of activated reaction gas, as well as the stoichiometry area of the synthesized coatings. Calculations were performed on the example of aluminum oxide. It was found that the plasma activation of the reactive gas allows to increase the sticking coefficient of oxygen to the surface of the growing coating from values less than 0.1 for non-activated molecular oxygen to 0.9 when 500 W of RF power is introduced into the inductive discharge. In order to verify the developed model, experiments were conducted on depositing an aluminum oxide film on glass substrates located at different distances from the magnetron target, followed by measuring the distribution of film transparency along the substrate length and comparing it with the calculated distribution. A comparison of the calculation results with the experimental data shows a good agreement in the entire studied range of parameters. Based on the generalization of the obtained results, an empirical rule was formulated that the power ratio of the magnetron discharge and the plasma activator should be approximately 8:1.