Iranian Journal of Applied Physics
https://jap.alzahra.ac.ir/
Iranian Journal of Applied Physicsendaily1Sun, 22 Sep 2024 00:00:00 +0330Sun, 22 Sep 2024 00:00:00 +0330Research Paper: A Numerical Generation of Gaussian and Non-Gaussian Isotropic/Anisotropic Rough Surfaces
https://jap.alzahra.ac.ir/article_7825.html
In the present study, the computer simulation has been used to generate the (1+1) and (2+1) surfaces with two types of correlation function Gaussian and correlation function Exponential forms. For this aim, a random number generator is used to generate the surfaces with Gaussian height distribution with zero mean, and their correlation functions were assumed to have Gaussian and exponential formulas. The calculations have been done for isotropic and anisotropic surfaces.&nbsp; For monofractal evaluation of rough surfaces, skewness and kurtosis values have been calculated for these (1+1) and (2+1) dimensional surfaces. Moreover, these values have been analyzed by the behavior of probability distribution of height. Also, the Hurst exponents of surfaces have been evaluated to study the irregularity and jaggedness of produced surfaces. Furthermore, the fractal dimension of these rough surfaces has been obtained to describe the complexity of the irregular fractal surfaces.Research Paper: Determining Trace Elements in Agricultural Products of Chogha Village of Arak, Iran
https://jap.alzahra.ac.ir/article_7815.html
All human beings need healthy nutrition to grow, so the lack or excess of low-amount elements causes diseases in humans, for this reason, it is essential to know the presence of elements in food. Arak aluminum production factory is located next to Chogha village, so it is necessary to study the effects of this factory and other industries in the region on its agricultural products. In this study, the content of 11 elements was determined: aluminum, bromine, calcium, chlorine, iron, magnesium, manganese, potassium, sodium, scandium, and zinc in crops as wheat, barley, peas, beans and alfalfa prepared from the village of Chogha in the Arak region by neutron activation analysis, as well as 3 other elements, including arsenic, lead, and cadmium were determined by inductively coupled plasma analysis. Magnesium concentration from 1310 to 3970, manganese from 15.2 to 66.3, sodium from 14.2 to 1490, aluminum from 5.72 to 914, chlorine from 364 to 12000, calcium from 413 to 29600, bromine from 0.23 to 14.50, potassium from 4740 to 14700, iron from 10.1 to 1310.0, scandium from 0.033 to 4.02, zinc from 27.7 to 96.7, arsenic from 0.000 to 0.021, lead from 0.000 to 0.003 and cadmium from 0.00 to 0.02 mg/kg. The results show that the concentration of chlorine, manganese, magnesium, iron, sodium, aluminum, bromine, calcium, scandium, zinc, and lead in alfalfa, the concentration of potassium in pinto beans, the concentration of cadmium in barley, and the concentration of arsenic in wheat are higher than another analyzed sample.Research Paper: Design and Construction of a Plasma Generation Device Using the Surface Dielectric Barrier Discharge (SDBD) Method in a Laboratory Scale
https://jap.alzahra.ac.ir/article_7594.html
This article aims to design and construct a plasma generation device using the surface dielectric barrier discharge method (SDBD) on a laboratory scale to produce a stable and uniform atmospheric pressure plasma layer. For this purpose, a copper electrode with a thickness of 100 microns with a comb- like structure was designed and constructed for this system, and a mica sheet with a thickness of 0.5 mm and dimensions of 10 &times; 10 cm was built to make the dielectric. According to the experimental data and analytical calculations of the constructed SDBD system in working conditions of 3 kV voltage and 12.5 kHz frequency, the consumption power of this system is calculated at 50 watts. Due to the production of stable and uniform plasma created on the dielectric surface and the measured power consumption, this system will be able to be used in various sciences and industries, including surface processing industries.Investigation of Tunneling Between the Edge States of Phosphorene Nanoribbon with Zigzag Edge
https://jap.alzahra.ac.ir/article_7718.html
In this paper, the transport properties of a phosphorene nanoribbon with zigzag edges are investigated. Although phosphorene is a two-dimensional structure with gaps, each zigzag edge of phosphorene nanoribbon acts like a one-dimensional quantum wire, so a nanoribbon with two edges is similar to two parallel quantum wires. We also show that by adding an impurity line between the upper and lower edges, we can create an impurity strip that can connect the upper edge to the lower edge. In other words, different inputs can be coupled to different outputs. To calculate coupling coefficients between inputs and outputs, we use the Lippmann-Schwinger formulation. The final results show that depending on the energy of the input state and the corresponding standing wave in the impurity band, the phenomenon of resonance or anti-resonance can be created in the dispersion between inputs and outputs. Besides the theoretical aspect of the proposed scheme presented in this article, it can be applied to make nanoswitches in practice.Red Phosphorus Nanoparticles in the Silicon Solar Cells for Higher Cell Efficiency and Converting the Ultraviolet to Visible Light Wavelength Range
https://jap.alzahra.ac.ir/article_7725.html
Red phosphorus nanoparticles were synthesized on the surface of the silicon solar cell by PVD technique (condensation on the cell surface from the vapor phase). The red phosphorous deposition on the surface of the cells was repeated several times with different thicknesses of the phosphorous layer, and after each deposition procedure, the efficiency of the silicon solar cell was measured. The obtained results demonstrated that after the deposition of 340 nm of phosphorous, the efficiency of the cell increased from 5.86 to 7.08, and about a 21% relative increase in efficiency was achieved. Moreover, the layers' absorption spectra and photoluminescence spectrum show that red phosphorus nanoparticles absorbed UV light and emitted visible light in addition to UV. In other words, the phosphorous layer has shifted the UV light to the visible light wavelength. In this research, a monocrystalline silicon solar cell was used to increase efficiency, and amorphous red phosphorus was deposited on the surface of the silicon solar cell by the PVD technique. In addition, to perform optical spectroscopy, a glass slide was placed next to the cells in each deposition step. The results of optical spectroscopy of phosphorous layers also showed that the amount of UV light transmission in the sample with a 340 nm phosphorous layer is lower than the sample with a 50 nm phosphorous layer. And vice versa, the amount of UV light absorption is higher, in other words, thicker phosphorous layers pass UV light less and absorb it more.&nbsp;Research Paper: Two-dimensional Analysis of the Bright Points Velocity in the Solar Transition Region with
the Local Correlation Tracking Method
https://jap.alzahra.ac.ir/article_7814.html
Our knowledge about the origin and transformation mechanisms of the bright points in the solar network has a significant role in understanding the ejection of materials and the transfer of energy into the solar corona. Outside the active region of the Sun (AR), although it is called the Quiet Sun (QS), various types of small-scale bright phenomena constantly occur within the boundary of the super granular cells above the magnetic network. Knowing the bright points is an effective key in considering the solar spicules. In this research, we study the solar transition region bright points and examine their apparent velocities with the local correlation tracking Fourier (FLCT) method. The results illustrate that these points differ in apparent velocity direction and brightness. Their lifetime and average horizontal velocity were estimated at 100 s and 4 kms-1, respectively. Recently, a new group of solar spicules has been observed, those lifetimes are around 100 s, and show a typical horizontal velocity of 3-4 kms-1. According to the analysis of the two-dimensional, apparent velocity of the bright points on the rosettes of the network, these points can be the disk counterpart of the type II spicules. In addition, the analysis of the two-dimensional field of velocities shows rotations that can cause the excitation of Alfvenic pulses.Research Paper: Designing Slow Light Waveguides Consisting of Two-dimensional Photonic Crystals and Investigating its Tunability
https://jap.alzahra.ac.ir/article_7866.html
The purpose of this research is to investigate the group velocity of tunable two-dimensional photonic crystals. The first step considers a square lattice consisting of dielectric rods in the liquid crystal background. In the next step, this structure was rotated by 45 degrees and its photonic band structure was investigated. Then, by removing a row of dielectric material (silicon) rods a waveguide is made in the photonic crystal. The waveguide mode and the related group velocity of the waveguide mode were investigated. In the following, the effect of applying an external voltage and changing the refractive index of the background material on the group velocity was studied. Afterward, by applying geometrical changes to the size of waveguide side rods, the effect of mentioned geometrical change on the properties of the waveguide mode and the group velocity was investigated. The calculation results show that the group velocity is reduced and as a result, the group index is increased.&nbsp; The investigations carried out show that quantitatively, by applying an external voltage in the ordinary waveguides, the range of changes in the group index is between 7 and 10, but by applying changes in modified waveguides, this quantity changes in the range of 14 to 27, which can be adjusted by applying an external electric field.&nbsp;Research Paper: Topological Phase Transition of InSb and InBi Under Nonhydrostatic Lattice Expansion
https://jap.alzahra.ac.ir/article_7889.html
This study investigated the topological phase transition of InSb and InBi under a non-hydrostatic lattice using density functional theory and the WIEN2K code. The results of examining the band structure of InSb and InBi employing the mBJGGA exchange-correlation potential indicate that InSb is a semiconductor with a small band gap and normal band order at the &Gamma; point. At the same time, InBi is a metal with band inversion at the Brillouin zone center. To transform these compounds into topological semiconductors, the lattice of these compounds is subjected to non-hydrostatic lattice expansion. Non-hydrostatic lattice expansion is applied in two ways. Firstly, the lattice constants are expanded in the ab plane while keeping the lattice constant along the c-axis constant. Then, the lattice constant is expanded along the c-axis while keeping the lattice constant in the ab plane constant. The calculations indicate that under the influence of both types of non-hydrostatic lattice expansion, with the breaking of cubic symmetry, a transition towards topological semiconductors occurs.The Effect of Plasma Sheath Turbulence on the Orbital Angular Momentum States of Bessel-Gaussian and Laguerre-Gaussian Beams
https://jap.alzahra.ac.ir/article_7741.html
In this work, detection probability of the orbital angular momentum (OAM) states of the Bessel-Gaussian (BG) and Laguerre-Gaussian (LG) beams passing through a plasma sheath turbulence (PST) are theoretically investigated. For this purpose, OAM-spectrum of the vortex beams (VB) is derived by using the modified von-Karman spectrum in the frame of Rytov theory, then some numerical analysis is performed to show the difference of considered VBs in the propagation through a PST. Obtained results indicate that incident beam parameters such as angular mode number, beam waist, and wavelength can easily affect the OAM-spectrum of both types of VBs. As well as, increasing the anisotropic parameters of the turbulent media can mitigate the turbulence-induced disturbance of the propagated VBs. Furthermore, it is found that diffraction-free BG beams show a better propagation performance than LG beams in the PST. This feature allows the BG beam to be a good candidate for free-space communication applications.&nbsp;Experimental Study of the Effect of Stress on the Magnetic Signatures of a Steel Sample
https://jap.alzahra.ac.ir/article_8014.html
Before sailing, submarines with ferromagnetic hulls are demagnetized to avoid damage and detection by sea mines and airborne systems. The increase in the residual magnetization of the submarine body after demagnetization due to the rising and falling can reduce the effect of demagnetization. This study aimed to investigate how internal hydrostatic pressure affects the magnetic signatures of a demagnetized submarine model. Magnetic sensors were placed at specific points under the body, and the changes in magnetic signatures were recorded when pressure was applied from 0 to 60 bar. The results show that by increasing the pressure up to 60 bar before demagnetization, the magnetic field components originating from the sample's internal stresses showed a linear increase. After depressurization, there was an exponential decrease followed by a subsequent increase in permanent magnetization of about 6%. However, after demagnetization, as the pressure increased up to 60 bar, the magnetic field generated by internal stresses in the sample increased by about 27%, but upon decreasing pressure, this magnetic field did not decrease but remained unchanged. This phenomenon negatively impacted the performance of the deperming process. Also, for further investigation, the increasing trend of magnetic signatures was evaluated at pressures of 30, 45, and 60 bar.Study of the Level Density and Thermodynamic Quantities for 256Cf98 and 290Fl114 Heavy and Superheavy Isotopes based on TD(P-E_shell)-BSFGM Considering the Effects of Spin, Parity, Rotation and Vibration
https://jap.alzahra.ac.ir/article_8015.html
Nuclear level density is a critical parameter in nuclear physics as it represents the number of energy levels per unit of energy (MeV) in a nucleus. This study calculates the level density and level density parameter for heavy and super heavy isotopes &nbsp;and based on the back-shifted Fermi gas method. The level density parameter is determined through a semi-classical approach using the nuclear Woods-Saxon potential. This research investigates the influence of pairing energy, and temperature-dependent shell effects on level density and thermodynamic quantities such as entropy, nuclear temperature, and nuclear-specific heat. Furthermore, the research explores the effects of nuclear spin, parity, rotational, and vibrational motion on these quantities. A graphical representation is used to illustrate the variations in nuclear level density, entropy, temperature, and specific heat as a function of nuclear excitation energy, highlighting the influence of nuclear spin, parity, and rotational and vibrational motions on them. The results show that considering these effects leads to changes in the parameters studied without altering the overall trends. Additionally, a specific heat diagram demonstrates the effects of vibrational and rotational motions, spin and parity effects, shell effects, and temperature-dependent pairing energy on excitation energy, revealing the breaking of the first nucleon pair at energies of E=2.948 MeV and E=3.04 MeV for isotopes and , respectively.Study the Electronic Structure and Magnetic Properties of Mxene Nb2C Using Ab-initio Study Method
https://jap.alzahra.ac.ir/article_8027.html
Today, research is directed toward finding new materials for various applications, from medicine to energy storage and other optoelectronic devices. Recently, a new phase of materials has been highlighted due to their flexible and machining nature known as Max Phases (Transition Metaln+1A(Al/Si)X(C/N)n) (MAX Phases). According to them, MAX Nb2AlC has been used in this work. Mxenes materials are obtained from these MAX phases by removing aluminum. There are different methods to obtain these two-dimensional materials, which are generally divided into two categories: experimental and simulation. Using the simulation method is more accurate due to being away from laboratory errors and cost-effective. Therefore, in this work, this method has been used to obtain Mxene niobium carbide and related calculations. For this purpose, the density functional theory and ab-initio method, which form the basis of the quantum espresso software package have been used to investigate the electronic and magnetic properties of this two-dimensional material. The obtained results show that this compound has good stability and good electronic conductivity, but it cannot be magnetized. To ensure the results of this research, the obtained results were compared with the results of experimental works and simulations of other researchers and it was found that they correspond very well.