Journal of Interfaces, Thin Films, and Low dimensional systems
https://jitf.alzahra.ac.ir/
Journal of Interfaces, Thin Films, and Low dimensional systemsendaily1Fri, 01 Jul 2022 00:00:00 +0430Fri, 01 Jul 2022 00:00:00 +0430Effect of temperature changes on thermoelectric properties of the two sided-closed single-walled Boron Nitride nanotubes (6, 3)
https://jitf.alzahra.ac.ir/article_6449.html
In this study, thermoelectric properties of the two sided-closed single-walled boron nitride nanotubes (TSC-SWBNNTs) are investigated. For this purpose, a nanotube with the chirality of (6, 3) is selected with no impurities. The energy is considered in the range of -5.5 to 5.5 electron volts and the investigations are performed at the temperatures 300, 500, 700 and 900K. The results show that increasing temperature results in significant reduction in the length of the bandgap. Besides, the peaks of the conduction diagram become smaller and their number decreases, indicating the return of more electrons and holes around the LUMO and HOMO bands, respectively, which leads to reduction of the bandgap and increase in the conduction. Moreover, the seebeck coefficient (thermal power) has increased to about 370 &mu;V/K by increasing temperature to 900K. As the temperature increases, the coefficient of merit (ZT) increases to about 0.95, and it is expected to experience more increase with further increase in temperature. Thermal conductivity has also increased slightly with increasing temperature. However, the values of thermal conductivity are at the nanoscale. Therefore, in general, it can be concluded that the (TSC-SWBNNT) (6, 3) can be selected as a suitable thermoelectric material.Interface roughness scattering effect on electrical properties of heterojunctions
https://jitf.alzahra.ac.ir/article_6353.html
In the present work, the effect of roughness in resonant tunneling diodes have been considered to track two main goals. At first, the roughness impact on the transport through these heterojunctions has been studied, and then roughness type effect have been also investigated. For calculating the electrical transport, the transfer matrix technique has been used in simulations. Two different standard methods of deposition - Random deposition (RD), and Ballistic deposition (BD)- have been applied to generate two dissimilar rough interfaces. The scattering process cause to reduction of transport probability. The conductivity as a function of voltage has been also calculated. Effect of interface roughness on the peak-to-valley current ratio in the presence of roughness have been discussed. The results show that the scattering affect it significantly. As the applied voltage increase, at first, the value of current reaches to maximum amount, and then with increasing the voltage, the current falls in a negative differential resistance region.Light hypernuclei formation in the hyperonization process of quark-gluon plasma
https://jitf.alzahra.ac.ir/article_6424.html
The purpose of this article is to describe the relativistic corrections to the spectrum of bound states during hyperonization when interactions between quarks and gluons in the semi-quark-gluon plasma occur and then appear color decay and color transformation between particles. I will consider this issue, according to the asymptotic behavior of the loop function in the scalar external gauge field based on the quantum field. This opinion was formed and presented using the projective unitary representation method and technique (oscillator representation method) based on the Schr&ouml;dinger equations converge toward the semi-relativistic equation and can take into account some relativistic effects of mass and interaction in a coupled system. Such calculations represent the interaction between the hyperon and the nuclei core when the quark-gluon plasma cooled down and we cannot see the free quarks and gluons, it occurs near the 150 MeV temperature in the quark-gluon plasma environment. The constituent mass and mass spectrum of hypernuclei presented with relativistic corrections. It is a new calculation and description of a coupled state of hadrons based on quantum field theory and the relativistic effect of interactions.Study of the physical properties of CdTe (200): synthesized nanoparticles and grown thin film
https://jitf.alzahra.ac.ir/article_6372.html
In this work, cadmium telluride nanoparticles were synthesized by sonochemical method and then thin films with the thicknesses about of 100 nm were deposited on glass substrates using thermal evaporation technique at a substrate temperature of 200 &deg;C and vacuum pressure of 2&times;10-5 mbar. Sonochemical method is one of the best methods for synthesizing nanomaterials with very small particle sizes. After synthesis and deposition, the prepared films were subjected to x-ray diffraction, ultraviolet-visible spectroscopy and scanning electron microscopy to study the structure, optical properties and morphology of the films. XRD patterns indicated that the grown films were polycrystalline with a cubic structure on the preferred orientation (200).The size of the synthesized nanoparticles and crystallite size of the thin film grown on glass in the preferred orientation (200) were 16 nm &amp;10.65 nm, respectively. Light absorbance spectra of nanoparticle and thin film obtained by UV-Vis spectroscopy at the wavelength range 600-1600 nm showed the increase of light absorption after deposition. The optical energy band gap was increased from 1.48 for nanoparticles to 1.51 for the deposited films. The SEM taken on the scale of 500 nm from nanoparticles and thin films showed the homogeneity and uniformity of both of themThe time delay between signals of tokamak magnetic coils and Its effect on the measurement of plasma displacement
https://jitf.alzahra.ac.ir/article_6371.html
The time delay between magnetic coil signals in a tokamak is believed to lead to inaccuracy in the measurement of the plasma physical parameters in the tokamak. In this research, we calculated the time delay between the signals of magnetic coils used in IR-T1 tokamak and investigated its effect on the measurement of the plasma horizontal displacement. The time delay between the signals of the magnetic coils was calculated utilizing time series analysis, and the horizontal displacement of the plasma was measured using the multipole moments method. The experimental results showed that by eliminating the time delay from the coil signals, the measurement of plasma horizontal displacement in IR-T1 tokamak was optimized.Temperature effect on femto-dimensional bound states
https://jitf.alzahra.ac.ir/article_6354.html
The bound state of exotic gluons with a thermal background in the framework of the projective unitary representation in the physics model at high energy interactions has been investigated. The ground and excited states of gluonic systems to describe the temperature effect of the mass spectrum have been defined. The problem of calculating the mass spectrum of coupled states based on the QFT in its broadest sense is a technique, to detect and obtain reasonable objectives and goals. The aim of this paper is to present the possible use of symplectic space in Femto-dimensional bound states at a finite temperature within strong interaction. The results can be used for describing nonzero and zero temperature mass spectra of mesons and multigluon-bound states. The problem of determining coupled state masses based on the polarization function is examined in detail. The Hamiltonian of the interaction and the structure of the bound state with the Schr&ouml;dinger equation within the color-confining potential and Debye mass at finite temperature is presented and then the mass spectrum of a glueball at high energy interaction is determined. The mass spectrum of a two-gluon coupled state is calculated. The results are presented in the figures and table.Entanglement dynamics of the two-spin system with time-dependent Heisenberg and Dzyaloshinskii-Moriya interactions
https://jitf.alzahra.ac.ir/article_6864.html
In the present paper, we study the entanglement dynamics of a two-spin system with Heisenberg interaction and Dzyaloshinskii-Moriya (DM)interaction. We assume that both interior interactions of the system are time-dependent. We consider two different scenarios: In the first case, both Heisenberg and DM interactions are sinusoidal function (sin(&omega;t)). The findings show that if time-dependency of the both interior interactions is same, the quantum entanglement of the system presents more robustness and its temporal fluctuations reduce significantly over the time.In the second case, DM interaction is considered as D&prop;cos(&omega;t). The findings imply that this kind of time-dependency causes the strong fluctuations of the entanglement, so that sometimes the correlation reaches zero. Therefore, in order to achieve a more stable entanglement over the time, it is better that the time dependency of the Heisenberg interaction and DM interaction are the same.Investigation of Zr Nanoparticle Effects on Structural Phase Stability, micro strains, and Flux Pinning in BSCCO-Zr/Cu doped HTSC
https://jitf.alzahra.ac.ir/article_6865.html
In this research, the resistivity of the BSCCO (Bi-2223) polycrystalline samples (x=0.0, 0.002, 0.0075, and 0.01) synthesized by the sol-gel method, has been investigated under magnetic fields. Also, the structural and morphological properties of ceramic superconductors have been studied by using X-ray diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) measurements. It is found that the Bi-2223 structural phase was formed more than other phases in the synthesized samples for x&le;0.0075. Based on the resistivity measurements, it is understood that the TC decreases with the increase in the Zr doping and the second superconducting transition is seen for the x&ge;0.0075. The thermally activated flux creep (TAFC) model has been investigated in synthesized ceramic superconductors. Furthermore, the magnetoresistivity behavior of all samples has been analyzed to determine the dependence of the pinning energy with applied magnetic fields and Zr doping. It found that the pinning energy remarkably decreased with the rise of Zr doping. Therefore, the creeping of vortices and crossing the energy barrier have occurred more easily and so the pinning energy is reduced by increasing Zr doping. Moreover, a good agreement between the modified TAFC model and the experimental data is concluded for the synthesized compounds.Simulation of hard X-ray time evolution in the stable region of plasma tokamak by using the NARX-GA hybrid neural network
https://jitf.alzahra.ac.ir/article_6874.html
Abstract
The time evolution of hard X-ray was simulated using the NARX-GA hybrid neural network in the stable region of the plasma tokamak. Loop voltage and hard X-ray measured by the tokamak diagnostics tools were selected as network inputs. The NARX network was trained using the Genetic Algorithm (GA) and accurately simulated the time evolution of the hard X-ray up to 500 &mu;s (MSE = 4.13&times;〖10〗^(-5)). Increasing the confinement time is the particular purpose of applying tokamak to produce energy through fusion. The real-time application of this methodology brings us closer to this goal. Hard X-ray prediction can prevent plasma energy reduction. It can also reduce the severe damage caused by runaway electrons (RE) colliding with the tokamak wall. Early prediction of hard X-ray time evolution is critical in attempting to mitigate the REs potentially dangerous effects.Entanglement, QFI and Squeezing of Hybrid State in non-inertial frame
https://jitf.alzahra.ac.ir/article_7017.html
We study the eect of the acceleration of the observer on the quan-tum Fisher information and entanglement using hybrid state. Thetwo-partite entangled hybrid state is consisted of discrete (vacuum andsingle photon) and continues (coherent states) variable states. Whenone of the observer (eg, Rob) is uniformly accelerated with respect toother partner, Alice, we nd that quantum Fisher information has amore stable structure than entanglement. Results show that quantumFisher information decreases with the increase of the acceleration butremains nite in the limit of innite acceleration that is in contrast withentanglement. Moreover, the eect of the acceleration is investigatedon the value of two-mode squeezing.Linear optical modeling on aluminum zig-zag thin films
https://jitf.alzahra.ac.ir/article_7018.html
The Al zig-zag sculptured thin film consists of two identical columns, the first nanocolumns (zig) are oriented at the angle &chi; and the second nanocolumns (zag) are oriented at the angle (&pi;- &chi;). The optical properties of these nanostructures were obtained using the transfer matrix method for linear s- and p- polarized incident lights in the wavelength range of 300-1000 nm. The reflection and transmission spectra of the zig-zag nanostructures with different arm numbers and lengths were obtained at different incident angles. The Bragg peaks begin to be appeared for zig-zag nanostructures of more than 4 arms for s- polarized light at the angles greater than 30. For zig-zag structures of 4, 8 and 16 arms, one, two and three Bragg peaks were observed, respectively. However, for p- polarized light, no Bragg peak was observed at any of the incident angles. Also, for the zig-zag structure of 8 arms for s-polarized light at 60 the incident angles, the number of Bragg peaks increases with increasing the arm length. In addition, the peaks created in the wavelengths below 550 nm showed red shift and the peaks appeared in the wavelengths above 550 nm showed blue shift.Modeling a high-performance broadband mid-infrared modulator using graphene-based hybrid plasmonic waveguide
https://jitf.alzahra.ac.ir/article_7020.html
A graphene based-hybrid plasmonic waveguide (GHPW) with unique geometric structure is designed for surface plasmon polariton (SPP) guidance and modulation at the frequency range of 10-30 THz. The GHPW is consist of a graphene layer in the middle, a high-density polyethylene (HDPE) gating layer, and two interior dielectric delimiter layers and two exterior semi-cylinder Germanium substrates symmetrically embedded on both edges of the graphene. Because of the matchless semi-cylinder structure design, the electromagnetic wave interaction with graphene ultimate subwavelength SPPs strong confinement with long propagation length. Small normalized mode area of ~〖10〗^(-4) and long propagation length of 10.67-28.92 &mu;m at Fermi energy of 1.0 eV is attained for SPPs modes propagation of the GHPW in the frequency bound of 10-30 THz and semi-cylinder radius R&gt;450 nm, respectively. By control the graphene Fermi energy, it is found that the structure has a modulation depth higher than 20% for the frequency band of 10-30 THz and arrives at the peak of approximately 100% at the frequency greater than 28.75 THz. To benefit from the great broadband MIR propagation and modulation efficiency, the GHPW may promise different MIR waveguides, modulators, photonic and optoelectronic devices.