Isfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Positronium atomic formation in the Eikonal direct approximationPositronium atomic formation in the Eikonal direct approximation112132610.29252/ijpr.18.1.1FAFShojaeiRFathiHAfaridehShAzizanMRahmanyanJournal Article20191126Positronium (Ps) formation in a ground state and 2s state of the hydrogen atom by positron impact has been studied within the framework of Eikonal direct approximation in the intermediate and high energy range. For this process, we compute Eikonal charge- exchange scattering amplitude, the differential and total cross sections by reducing the six-dimensional integrals to one-dimensional integrals. Numerical results have been compared with some existing theoretical results and experimental findings.Positronium (Ps) formation in a ground state and 2s state of the hydrogen atom by positron impact has been studied within the framework of Eikonal direct approximation in the intermediate and high energy range. For this process, we compute Eikonal charge- exchange scattering amplitude, the differential and total cross sections by reducing the six-dimensional integrals to one-dimensional integrals. Numerical results have been compared with some existing theoretical results and experimental findings.https://ijpr.iut.ac.ir/article_1326_a6bf2822ddcdafa7e1bd412afde5183a.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Generalization of the Dirichlet to Neumann map method for investigating the band structure of annular metallic photonic crystalsGeneralization of the Dirichlet to Neumann map method for investigating the band structure of annular metallic photonic crystals1322132710.29252/ijpr.18.1.13FAA ASedghiJournal Article20191126Using the Dirichlet-Neumann mapping method, we were able to calculate the photonic band structure of the annular metal photonic crystals. The surveyed grid is square and scattering centers (bars) are in the form of air rings located on the metal surface, as well as metal rings located in the air. The photonic band structure is calculated for both polarizations E and H for electromagnetic waves. The results indicate that there are frequency bands (photon strips) plus flat bands at low light speeds. The effect of the size of the air and metal rings on photonic tape structures has been theoretically investigatedUsing the Dirichlet-Neumann mapping method, we were able to calculate the photonic band structure of the annular metal photonic crystals. The surveyed grid is square and scattering centers (bars) are in the form of air rings located on the metal surface, as well as metal rings located in the air. The photonic band structure is calculated for both polarizations E and H for electromagnetic waves. The results indicate that there are frequency bands (photon strips) plus flat bands at low light speeds. The effect of the size of the air and metal rings on photonic tape structures has been theoretically investigatedhttps://ijpr.iut.ac.ir/article_1327_ba5580601209d31f7fafe6e9c82184cb.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Standard Abelian duality transformations in f(T) gravityStandard Abelian duality transformations in f(T) gravity2329132810.29252/ijpr.18.1.23FAMAtazadehAEghbaliJournal Article20191126According to the perturbation order, the equations of motion of low-energy string effective action are the generalized Einstein equations. Thus, by making use of the conformal transformation of the metric tensor, it is possible to map the low-energy string effective action into f(T) gravity, relating the dilaton field to the torsion scalar. Considering a homogeneous and isotropic universe and writing the canonical Lagrangian for f(T) gravity, we show that the invariance under the duality transformation holds for the cosmic scale factor a(t) at the level of the Lagrangian. Finally, by use of the dualized Lagrangian and also the invariance of torsion scalar under the scale factor duality a(t)→1/a(t), the specific form of the f(T) function is obtained.According to the perturbation order, the equations of motion of low-energy string effective action are the generalized Einstein equations. Thus, by making use of the conformal transformation of the metric tensor, it is possible to map the low-energy string effective action into f(T) gravity, relating the dilaton field to the torsion scalar. Considering a homogeneous and isotropic universe and writing the canonical Lagrangian for f(T) gravity, we show that the invariance under the duality transformation holds for the cosmic scale factor a(t) at the level of the Lagrangian. Finally, by use of the dualized Lagrangian and also the invariance of torsion scalar under the scale factor duality a(t)→1/a(t), the specific form of the f(T) function is obtained.https://ijpr.iut.ac.ir/article_1328_1b156adbc00fdcd8872b43e4cd9d6d58.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Holographic calculation of two-point correlation functions of CFT stress tensor in the BMS gauge and flat-space holographyHolographic calculation of two-point correlation functions of CFT stress tensor in the BMS gauge and flat-space holography3137132910.29252/ijpr.18.1.31FARFareghbalPKarimiJournal Article20191126In this paper, we use the holographic renormalization method to calculate the two-point correlation functions of the CFT stress tensor. In the gravity side, we write the asymptotically AdS spacetimes in the BMS gauge and apply the standard holographic renormalization method for these space-times. The significance of using multi-point functions in this gauge is that its flat-space limit is well-defined. We discuss this point in the last section of the paper.
In this paper, we use the holographic renormalization method to calculate the two-point correlation functions of the CFT stress tensor. In the gravity side, we write the asymptotically AdS spacetimes in the BMS gauge and apply the standard holographic renormalization method for these space-times. The significance of using multi-point functions in this gauge is that its flat-space limit is well-defined. We discuss this point in the last section of the paper.
https://ijpr.iut.ac.ir/article_1329_0ea5628eef77dfac83615006acfc1f8c.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Parameterization of Woods-Saxon potential in view of Particle-vibration coupling for 208PbParameterization of Woods-Saxon potential in view of Particle-vibration coupling for 208Pb3947133010.29252/ijpr.18.1.39FALRafat-MotavalliS HMiri-HakimabadEHoseinian-AzghadiJournal Article20191126In this study, the particle-vibration coupling for nuclei around 208Pb was taken into account. Then, Hamiltonian matrix in the basis of particle vibration eigenvectors was constructed and after matrix Diagonalization, fitting with experimental states was performed. Therefore, a set of pure single particle states was obtained which also called modified experimental levels. The results show that the neutron and proton energy gap were considerably increased to 0.81 MeV and 0.39 MeV in modified spectrum, respectively. The shell model parameters of phenomenological Woods-Saxon (WS) potential was then adjusted to reproduce these modified experimental states. The results showed that, WS potential with the help of new parameters predict the experimental states more precisely. In this study, the particle-vibration coupling for nuclei around 208Pb was taken into account. Then, Hamiltonian matrix in the basis of particle vibration eigenvectors was constructed and after matrix Diagonalization, fitting with experimental states was performed. Therefore, a set of pure single particle states was obtained which also called modified experimental levels. The results show that the neutron and proton energy gap were considerably increased to 0.81 MeV and 0.39 MeV in modified spectrum, respectively. The shell model parameters of phenomenological Woods-Saxon (WS) potential was then adjusted to reproduce these modified experimental states. The results showed that, WS potential with the help of new parameters predict the experimental states more precisely. https://ijpr.iut.ac.ir/article_1330_89dfc6e5c3f42fc2195b0af413b307a1.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Ambiguity in the value of the structure function of many fermion systems at the very small momentum transferAmbiguity in the value of the structure function of many fermion systems at the very small momentum transfer4951133110.29252/ijpr.18.1.49FAYYounesizadehJournal Article20191126First the structure function of the many fermion systems is written in terms of the fluctuation of the target density and too the value of this function at very small momentum transfer is calculated. It is shown that the values of the structure function of these systems at very small momentum transfer calculated from two different ways which one is the mathematical straight way and other way is the sum rules of the quantum fluids, are not equal. This topic transparently is a paradox for the many-fermion systems and must be considered. Finally for removing this paradox, we offer a new defination for the response function or the structure function of the many fermion systems.First the structure function of the many fermion systems is written in terms of the fluctuation of the target density and too the value of this function at very small momentum transfer is calculated. It is shown that the values of the structure function of these systems at very small momentum transfer calculated from two different ways which one is the mathematical straight way and other way is the sum rules of the quantum fluids, are not equal. This topic transparently is a paradox for the many-fermion systems and must be considered. Finally for removing this paradox, we offer a new defination for the response function or the structure function of the many fermion systems.https://ijpr.iut.ac.ir/article_1331_665c7dd8a9d298cc31fbfcde3263678a.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Rotation of the free layer of titanium dioxide nano-fluid in an external electric fieldRotation of the free layer of titanium dioxide nano-fluid in an external electric field5357133210.29252/ijpr.18.1.53FAMSoleimani TabarRRasulRShirsavarSMollaeiJournal Article20191126In this paper, the effect of titanium dioxide nanoparticles on the response of the freely suspended nano-fluid was investigated in an external electric field. Applying the external electric field to liquid film carrying electric current caused the layer rotation. It was due to the surface charge response of the layer to the electric field. The effect of surface charge on titanium dioxide nano-fluid rotation at various concentrations was studied. The results showed that the presence of nanoparticles in the fluid doubled the rotation velocity. Also, the effect of ultraviolet radiation on the rotation velocity of the fluid was examined, showing that there was no significant impact on rotation velocity. Finally, the needed time to reach the maximum rotation velocity of the nano-fluids layers was measured In this paper, the effect of titanium dioxide nanoparticles on the response of the freely suspended nano-fluid was investigated in an external electric field. Applying the external electric field to liquid film carrying electric current caused the layer rotation. It was due to the surface charge response of the layer to the electric field. The effect of surface charge on titanium dioxide nano-fluid rotation at various concentrations was studied. The results showed that the presence of nanoparticles in the fluid doubled the rotation velocity. Also, the effect of ultraviolet radiation on the rotation velocity of the fluid was examined, showing that there was no significant impact on rotation velocity. Finally, the needed time to reach the maximum rotation velocity of the nano-fluids layers was measured https://ijpr.iut.ac.ir/article_1332_25895e1d99a72d3e66104f8fcdf7d549.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Study of synthesis of some Flerovium isotopes, Fl, in the island of stability and comparison of their fusion barrier parametersStudy of synthesis of some Flerovium isotopes, Fl, in the island of stability and comparison of their fusion barrier parameters5966133310.29252/ijpr.18.1.59FAHEslamizadehJournal Article20191126In the present research, we want to study synthesis of some isotopes of Flerovium ، ، and were produced in the nuclear fusion of 48Ca ions with 239Pu, 240Pu, 241Pu, and 242Pu nuclei. We obtain the parameters of the fusion barriers between48Ca ions with Pu isotopes and compare these parameters with each other. Furthermore, we investigate influence of the direction of target nuclei on the parameters of the fusion barriers. we show that the minimum energies for synthesis of 287Fl, 288Fl, 289Fl and 290Fl nuclei are 184.16 MeV, 183.95 MeV, 183.75 MeV and 183.56 MeV. Finally in the framework of the statistical model, we estimate the evaporation residue cross section for 286Fl, 287Fl nuclei after emission of three and four neutrons from 290Fl nuclei and we will show that the results of calculations for 286Fl nuclei are in good agreement with the experimental data. Although, the results of the calculations of the evaporation residue cross section for 287Fl nuclei lie somewhat below the results of the experimental data.In the present research, we want to study synthesis of some isotopes of Flerovium ، ، and were produced in the nuclear fusion of 48Ca ions with 239Pu, 240Pu, 241Pu, and 242Pu nuclei. We obtain the parameters of the fusion barriers between48Ca ions with Pu isotopes and compare these parameters with each other. Furthermore, we investigate influence of the direction of target nuclei on the parameters of the fusion barriers. we show that the minimum energies for synthesis of 287Fl, 288Fl, 289Fl and 290Fl nuclei are 184.16 MeV, 183.95 MeV, 183.75 MeV and 183.56 MeV. Finally in the framework of the statistical model, we estimate the evaporation residue cross section for 286Fl, 287Fl nuclei after emission of three and four neutrons from 290Fl nuclei and we will show that the results of calculations for 286Fl nuclei are in good agreement with the experimental data. Although, the results of the calculations of the evaporation residue cross section for 287Fl nuclei lie somewhat below the results of the experimental data.https://ijpr.iut.ac.ir/article_1333_a932ed64b3c990c1c6a72bcf9e1f77b1.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Measuring the optical depth profile of galaxy clusters by kinetic Sunyaev-Zel'dovic effectMeasuring the optical depth profile of galaxy clusters by kinetic Sunyaev-Zel'dovic effect6773133410.29252/ijpr.18.1.67FAShBaghramJournal Article20191126baryonic matter distribution in the large-scale structures is one of the main questions in cosmology. This distribution can provide valuable information regarding the processes of galaxy formation and evolution. On the other hand, the missing baryon problem is still under debate. One of the most important cosmological structures for studying the rate and the distribution of the baryons is galaxy clusters. In this work, it is proposed that the kinetic Sunyaev-Zel'dovich effect in galaxy clusters, which has a supernova type Ia (SNe Ia) in their brightest central galaxy, can be used to obtain the optical depth profile of the galaxy cluster. To obtain this profile , the bulk velocity is calculated by SNe Ia. We show that for galaxy clusters in the redshift range of Z<0.15
, we can find the optical depth with 100 kpc resolution, which is the same as 1 arc minute resolution in cosmic microwave background observations.baryonic matter distribution in the large-scale structures is one of the main questions in cosmology. This distribution can provide valuable information regarding the processes of galaxy formation and evolution. On the other hand, the missing baryon problem is still under debate. One of the most important cosmological structures for studying the rate and the distribution of the baryons is galaxy clusters. In this work, it is proposed that the kinetic Sunyaev-Zel'dovich effect in galaxy clusters, which has a supernova type Ia (SNe Ia) in their brightest central galaxy, can be used to obtain the optical depth profile of the galaxy cluster. To obtain this profile , the bulk velocity is calculated by SNe Ia. We show that for galaxy clusters in the redshift range of Z<0.15
, we can find the optical depth with 100 kpc resolution, which is the same as 1 arc minute resolution in cosmic microwave background observations.https://ijpr.iut.ac.ir/article_1334_08ee8f33bbfb885d612339b2c6d1c869.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Inflationary Cosmology in Anisotropic Inflation ModelsInflationary Cosmology in Anisotropic Inflation Models7580133510.29252/ijpr.18.1.75FAHFirouzjahiA AAbolhasaniJournal Article20191126In this work, we study the anisotropic inflationary models . In these models, an abelian gauge field non-minimally coupled to the inflaton field plays a role in the inflation dynamicIn a gauge field,the backgroundanswer is anisotropic, in the form of metric Bianchi. In order for the model to be consistent with the observations, the level of anisotropy should be small. The anisotropy power spectrum is obtained by calculating cosmological perturbation using formalism. We show that the criticism levelled in [4] does not apply and we can repeat the calculations in the non-absorbence by calculating the anisotropy spectrum. Using the constraint on the quadrupole anisotopy, we show that the contribution of the gauge field to total energy density should be very small
In this work, we study the anisotropic inflationary models . In these models, an abelian gauge field non-minimally coupled to the inflaton field plays a role in the inflation dynamicIn a gauge field,the backgroundanswer is anisotropic, in the form of metric Bianchi. In order for the model to be consistent with the observations, the level of anisotropy should be small. The anisotropy power spectrum is obtained by calculating cosmological perturbation using formalism. We show that the criticism levelled in [4] does not apply and we can repeat the calculations in the non-absorbence by calculating the anisotropy spectrum. Using the constraint on the quadrupole anisotopy, we show that the contribution of the gauge field to total energy density should be very small
https://ijpr.iut.ac.ir/article_1335_0c628f64a8a9bed999aa123b19d30406.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Determination of optimum Distance for ALBORZ-1 arrayDetermination of optimum Distance for ALBORZ-1 array8189133610.29252/ijpr.18.1.81FAGRastegarzadeh0000-0001-9240-7841LRafeziJournal Article20191126Optimum distance is defined as a distance from the air -shower core in which the density of a number of particles calculated by the lateral distribution function at that distance has the least uncertainty. Furthermore, with a good approximation, this distance is independent of the characteristics of primitive ray and it only depends on the geometric shape of array . In this paper, by simulating 1000 vertical EAS of protons with the energy 300 TeV , using the CORSIKA Monte Carlo code and trigger condition, the calculated distance for the array triggering ALBORZ-1 was found to be equal to 9±1 m. Also, it was found that this distance as well as the density of the number of calculated particles was independent of the lateral distribution function used in the calculations
Optimum distance is defined as a distance from the air -shower core in which the density of a number of particles calculated by the lateral distribution function at that distance has the least uncertainty. Furthermore, with a good approximation, this distance is independent of the characteristics of primitive ray and it only depends on the geometric shape of array . In this paper, by simulating 1000 vertical EAS of protons with the energy 300 TeV , using the CORSIKA Monte Carlo code and trigger condition, the calculated distance for the array triggering ALBORZ-1 was found to be equal to 9±1 m. Also, it was found that this distance as well as the density of the number of calculated particles was independent of the lateral distribution function used in the calculations
https://ijpr.iut.ac.ir/article_1336_1c931839f6e1598318a5d0ee720dd201.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Trace of energy-momentum tensor and gravitational backreaction of Schwinger scalars in 3D de Sitter spacetimeTrace of energy-momentum tensor and gravitational backreaction of Schwinger scalars in 3D de Sitter spacetime91103133710.29252/ijpr.18.1.91FAEBavarsadMMortezazadehJournal Article20191126In this paper, we consider a massive charged scalar field coupled to a uniform electric field background in a 3 dimensional de Sitter spacetime. We consider the value of the dimensionless coupling constant of the scalar field to the scalar curvature of a 3 dimensional de Sitter spacetime equal to 1/8. We compute the expectation value of the trace of the energy-momentum tensor in the in-vacuum state and we show that using adiabatic subtraction regularization method the linear ultraviolet divergence is removed and a finite expression obtain. We investigate the behavior of the regularized trace for different intensities of the scalar field mass and the electric field. We show that the trace as a function of the electric field has a discontinuity at which it changes the sign. We show that for the case of a conformally coupled scalar field to the de Sitter spacetime the trace vanishes, and there is no trace anomaly. We discuss the gravitational backreaction effect of the created Schwinger pairs.
In this paper, we consider a massive charged scalar field coupled to a uniform electric field background in a 3 dimensional de Sitter spacetime. We consider the value of the dimensionless coupling constant of the scalar field to the scalar curvature of a 3 dimensional de Sitter spacetime equal to 1/8. We compute the expectation value of the trace of the energy-momentum tensor in the in-vacuum state and we show that using adiabatic subtraction regularization method the linear ultraviolet divergence is removed and a finite expression obtain. We investigate the behavior of the regularized trace for different intensities of the scalar field mass and the electric field. We show that the trace as a function of the electric field has a discontinuity at which it changes the sign. We show that for the case of a conformally coupled scalar field to the de Sitter spacetime the trace vanishes, and there is no trace anomaly. We discuss the gravitational backreaction effect of the created Schwinger pairs.
https://ijpr.iut.ac.ir/article_1337_224f2fc1957c9c07d007bb776dcd6baa.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Crystal field and Ce3+ ion energy levels of CeCl3 compoundCrystal field and Ce3+ ion energy levels of CeCl3 compound105113133810.29252/ijpr.18.1.105FALMollabashiESadeghi KelishadiSJalali-AsadabadiJournal Article20191126In this paper, the crystal field parameters (CFPs) have been calculated in the framework of the density functional theory using a novel theoretical approach proposed by Pavel Novák et al. and extracting the WANNIER functions from the Bloch eigenstates for the CeCl3 compound. Then, the calculated CFPs have been used in an effective atomic-like Hamiltonian, including the crystal field, 4f-4f correlation and spin-orbit coupling, and the splitted energy levels of Ce3+ ion by crystal field have been derived by diagonalization of the Hamiltonian. A hybridization parameter, , has been used to improve the results. The results are found to be in agreement with the experimental dataIn this paper, the crystal field parameters (CFPs) have been calculated in the framework of the density functional theory using a novel theoretical approach proposed by Pavel Novák et al. and extracting the WANNIER functions from the Bloch eigenstates for the CeCl3 compound. Then, the calculated CFPs have been used in an effective atomic-like Hamiltonian, including the crystal field, 4f-4f correlation and spin-orbit coupling, and the splitted energy levels of Ce3+ ion by crystal field have been derived by diagonalization of the Hamiltonian. A hybridization parameter, , has been used to improve the results. The results are found to be in agreement with the experimental datahttps://ijpr.iut.ac.ir/article_1338_b21750288dd56b4e6bbe1b87691df227.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Fourier Domain Optical Coherence Tomography for Simultaneous Measurement of Refractive Index and Physical Thickness of Multiple layersFourier Domain Optical Coherence Tomography for Simultaneous Measurement of Refractive Index and Physical Thickness of Multiple layers115124133910.29252/ijpr.18.1.115FAAAmjadiKhGhasemi FalavarjaniNMoazami GudarziJournal Article20191126In fourier domain optical coherence tomography, we can measure the optical thickness ( refractive index n times thickness d), to obtain the retinal layers in order to diagnose many disorders. In this work, we introduce a new method for measurement of refractive index and physical thickness of multiple layers simultaneously by Fourier domain optical coherence tomography, without additional information about the structure of the sample under investigation. The input data to the formulation are the interference spectrum of FD-OCT system and the optical path lengths (OPLs) which obtain from fast fourier transform of interference spectrum. The output of simulation suggest that, the accuracy of the extracted parameters depend on the difference in the refractive index gradient of sample interfaces. Furthermore, we show that the accuracy of the extracted parameters can be affected by uncertainty in obtained OPLs. So, we introduce a method to optimize the accuracy of parameters in spite of uncertainty in measuring OPLs. Simulation results show that, for transparent biological sample merge into an aqueous media, if sample layers has indices less than 1.55 , these parameters can be extracted with the , less than 0.001 .In fourier domain optical coherence tomography, we can measure the optical thickness ( refractive index n times thickness d), to obtain the retinal layers in order to diagnose many disorders. In this work, we introduce a new method for measurement of refractive index and physical thickness of multiple layers simultaneously by Fourier domain optical coherence tomography, without additional information about the structure of the sample under investigation. The input data to the formulation are the interference spectrum of FD-OCT system and the optical path lengths (OPLs) which obtain from fast fourier transform of interference spectrum. The output of simulation suggest that, the accuracy of the extracted parameters depend on the difference in the refractive index gradient of sample interfaces. Furthermore, we show that the accuracy of the extracted parameters can be affected by uncertainty in obtained OPLs. So, we introduce a method to optimize the accuracy of parameters in spite of uncertainty in measuring OPLs. Simulation results show that, for transparent biological sample merge into an aqueous media, if sample layers has indices less than 1.55 , these parameters can be extracted with the , less than 0.001 .https://ijpr.iut.ac.ir/article_1339_41544c1e55faf125aa5ca5a37f6fbe27.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Numerical analysis of fold-pitchfork bifurcation with symmetry and its application in the pipe flowNumerical analysis of fold-pitchfork bifurcation with symmetry and its application in the pipe flow125137134010.29252/ijpr.18.1.125FARMazrooei-Sebdani0000-0002-2077-1887ZEskandariJournal Article20191126In this paper, we study the numerical analysis of fold-pitchfork bifurcation with Z2 symmetry. For this purpose, explicit formulas for the critical coefficients of this bifurcation are obtained and non-degeneracy conditions of this bifurcation are determined. Then, local bifurcations, bifurcation curves and phase portraits are computed by MatCont toolbox. We will emphasize an example serving as a model of pipe flowIn this paper, we study the numerical analysis of fold-pitchfork bifurcation with Z2 symmetry. For this purpose, explicit formulas for the critical coefficients of this bifurcation are obtained and non-degeneracy conditions of this bifurcation are determined. Then, local bifurcations, bifurcation curves and phase portraits are computed by MatCont toolbox. We will emphasize an example serving as a model of pipe flowhttps://ijpr.iut.ac.ir/article_1340_993c45a9fdb35c1db7452208b10472a4.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Investigation of solution effect on the EPR spectrum of alanine radicals based on density functional theoryInvestigation of solution effect on the EPR spectrum of alanine radicals based on density functional theory139150134110.29252/ijpr.18.1.139FAMJanbaziYTaghipour AzarFZiaieJournal Article20191126In this study, based on Density Functional Theory (DFT), the effect of solution on the g-tensor, hyperfine coupling constant of atoms and finally the EPR spectrum of alanine free radicals induced by ionizing radiation such as electron and gamma was investigated using implicit models such as COSMO, and explicit models such as introducing hydrogen bonds to the cluster structures. The obtained results confirmed a good consistency between the g-tensor and hyperfine coupling constant of atoms and the experimental data in the solution as well as qualitatively in the crystal by the introduction of the hydrogen bond of the water molecule to the cluster models. The use of different clusters in constituting hydrogen bonds between water molecule and radicals indicated that in the first shell, four, seven and six water molecules were needed for R1, R2 and R3 radicals, respectively. Moreover, the effect of solution on EPR spectrum was analyzed in a manner that the identity of the radical remained unchanged. In this study, based on Density Functional Theory (DFT), the effect of solution on the g-tensor, hyperfine coupling constant of atoms and finally the EPR spectrum of alanine free radicals induced by ionizing radiation such as electron and gamma was investigated using implicit models such as COSMO, and explicit models such as introducing hydrogen bonds to the cluster structures. The obtained results confirmed a good consistency between the g-tensor and hyperfine coupling constant of atoms and the experimental data in the solution as well as qualitatively in the crystal by the introduction of the hydrogen bond of the water molecule to the cluster models. The use of different clusters in constituting hydrogen bonds between water molecule and radicals indicated that in the first shell, four, seven and six water molecules were needed for R1, R2 and R3 radicals, respectively. Moreover, the effect of solution on EPR spectrum was analyzed in a manner that the identity of the radical remained unchanged. https://ijpr.iut.ac.ir/article_1341_5d1514b139ba0e808b2c465b17da16ae.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Simulation of the physical properties of BaMnxMo1-xO3 (x=0, 0.5, 1) perovskite compound using density functional theory and Hubbardâs correctionSimulation of the physical properties of BaMnxMo1-xO3 (x=0, 0.5, 1) perovskite compound using density functional theory and Hubbardâs correction151156134210.29252/ijpr.18.1.151FAAMokhtariREbrahimi JaberiJournal Article20191126In this paper, we have simulated the physical properties of BaMnxMo1-xO3 (x=0, 0.5, 1) perovskite compound by the density functional theory and Hubbard model, using the Espersso code. To calculate the exchange-correlation potential in the Kohn Sham equations, the generalized gradient approximation (GGA) has been used. Also, because the calculated results indicate that U parameter plays a vital role in determining the electronic characterization in our compound, we have repeated our calculations using the LDA+U instead of the GGA approximation. In both GGA and LDA+U approximations, we have studied the ferromagnetic state of the cubic phase of BaMnxMo1-xO3 (x=0, 0.5, 1) compound. Then, we have investigated the behaviour of the Lattice Parameter, Cohesive Energy, Total Magnetization and Bulk Module of the corresponding compound for the different values of x. After that, by fitting our results using the second order polynomial function, we have studied the reasons for the deviation from Vegard’s law for each parameter.In this paper, we have simulated the physical properties of BaMnxMo1-xO3 (x=0, 0.5, 1) perovskite compound by the density functional theory and Hubbard model, using the Espersso code. To calculate the exchange-correlation potential in the Kohn Sham equations, the generalized gradient approximation (GGA) has been used. Also, because the calculated results indicate that U parameter plays a vital role in determining the electronic characterization in our compound, we have repeated our calculations using the LDA+U instead of the GGA approximation. In both GGA and LDA+U approximations, we have studied the ferromagnetic state of the cubic phase of BaMnxMo1-xO3 (x=0, 0.5, 1) compound. Then, we have investigated the behaviour of the Lattice Parameter, Cohesive Energy, Total Magnetization and Bulk Module of the corresponding compound for the different values of x. After that, by fitting our results using the second order polynomial function, we have studied the reasons for the deviation from Vegard’s law for each parameter.https://ijpr.iut.ac.ir/article_1342_f195b765b3ab7ed45d8f119cee5bec64.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Feasibility of the use of ( ZnxHg(1-x)Te ternary compound as a spectrometer of nuclear radiationsFeasibility of the use of ( ZnxHg(1-x)Te ternary compound as a spectrometer of nuclear radiations157162134310.29252/ijpr.18.1.157FAHGhasemiAMokhtariFPayamiVSoleimanianJournal Article20191126In this paper in order to achieve a suitable spectrometer for nuclear radiation detection at room temperature, effect of adding the element Hg to binary compound semiconductor ZnTe was studied completely. Electronic structure and transport properties of ternary compound semiconductor ZnxHg(1-x)Te (ZHT) simulated using ABINIT as a computational code based on density functional theory. According to this simulation the range of x≥0.8 was selected. This simulations including good response function compared to CdTe simulated by using MCNP as a computational code, shows that ZHT in the above range is a suitable nuclear spectrometer at room temperature.In this paper in order to achieve a suitable spectrometer for nuclear radiation detection at room temperature, effect of adding the element Hg to binary compound semiconductor ZnTe was studied completely. Electronic structure and transport properties of ternary compound semiconductor ZnxHg(1-x)Te (ZHT) simulated using ABINIT as a computational code based on density functional theory. According to this simulation the range of x≥0.8 was selected. This simulations including good response function compared to CdTe simulated by using MCNP as a computational code, shows that ZHT in the above range is a suitable nuclear spectrometer at room temperature.https://ijpr.iut.ac.ir/article_1343_5e93e5d24114a365e08cef66b7abd74b.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126Phantom divide crossing with non-minimal kinetic and gauss-bonnet couplingsPhantom divide crossing with non-minimal kinetic and gauss-bonnet couplings163166134410.29252/ijpr.18.1.163FAABanijamaliRRoohollahiMVaezJournal Article20191126In this paper we study a dark energy model in which tachyon scalar field non-minimally coupled with kinetic energy and Gauss-Bonnet invariant. Energy density рø, pressure рø and scalar field equation of motion have been calculated and then equation of state parameter has been extracted. We have investigated the conditions required for ω=-1 crossing in such a model. It is shown that phantom divide crossing can be realized in our model.
In this paper we study a dark energy model in which tachyon scalar field non-minimally coupled with kinetic energy and Gauss-Bonnet invariant. Energy density рø, pressure рø and scalar field equation of motion have been calculated and then equation of state parameter has been extracted. We have investigated the conditions required for ω=-1 crossing in such a model. It is shown that phantom divide crossing can be realized in our model.
https://ijpr.iut.ac.ir/article_1344_df46bba0f67eb466131f89f126c1fbf5.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695718120191126A planar metamaterial design for electromagnetically induced transparencyA planar metamaterial design for electromagnetically induced transparency167175134510.29252/ijpr.18.1.167FAُ SAhmadiARezaei-LatifiJournal Article20191126Electromagnetically induced transparency is an optical phenomenon that is characterized by the elimination of the effect of a medium on a propagating beam of electromagnetic radiation in a specific frequency band. In this study, EIT was investigated at a proposed metamaterial with the dimensions milimeter and in the area of frequency of GHz. The computation results indicated that EIT with high transmission rate and high Q factor occurs in certain frequencies by breaking the symmetry in this structure. The sensitivity studies showed that the use of silver in the structure increases the quality factor so significantly that this quantity reaches 338 for gold and copper, while it reaches 677 for silver. In addition, By reducing the temperature, the transmission rate in the structure increases and reaches acceptable degree 98%. This structure can be an appropriate option for slow light usages, and it can be utilized for light amplification in microwave structures.Electromagnetically induced transparency is an optical phenomenon that is characterized by the elimination of the effect of a medium on a propagating beam of electromagnetic radiation in a specific frequency band. In this study, EIT was investigated at a proposed metamaterial with the dimensions milimeter and in the area of frequency of GHz. The computation results indicated that EIT with high transmission rate and high Q factor occurs in certain frequencies by breaking the symmetry in this structure. The sensitivity studies showed that the use of silver in the structure increases the quality factor so significantly that this quantity reaches 338 for gold and copper, while it reaches 677 for silver. In addition, By reducing the temperature, the transmission rate in the structure increases and reaches acceptable degree 98%. This structure can be an appropriate option for slow light usages, and it can be utilized for light amplification in microwave structures.https://ijpr.iut.ac.ir/article_1345_f01622ebc6f0bbfa48a463af17f5f7e4.pdf