Isfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695715320191126Estimation of lattice strain in metallic oxideâorganic material nanocomposite using Williamson-Hall equationEstimation of lattice strain in metallic oxideâorganic material nanocomposite using Williamson-Hall equation279282114710.18869/acadpub.ijpr.15.3.279FAMRoodbari ShahmiriABahariFRostamianMBaradaran KhanianiJournal Article20191126In the present work, metallic oxide–organic material hybrid nanocomposites (Poly vinyl pyrrolidone- zinc oxide, PVP-ZnO) have been synthesized using sol-gel method. Nanostructural properties of aforementioned materials were studied by scanning electron microscope (SEM) and X-ray diffraction techniques. Williamson equation was used to estimate lattice strain in the PVP-ZnO nanocomposite. The dominated peaks in XRD spectra and Williamson- Hall diagrams were considered and the nano crystallite strain was plotted by drawing strain slopes. The obtained results showed that hybrid nanocomposites synthesized at 150ºC have lower strain and therefore higher yield strain. The SEM image indicated that nanoparticles are distributed uniformly.In the present work, metallic oxide–organic material hybrid nanocomposites (Poly vinyl pyrrolidone- zinc oxide, PVP-ZnO) have been synthesized using sol-gel method. Nanostructural properties of aforementioned materials were studied by scanning electron microscope (SEM) and X-ray diffraction techniques. Williamson equation was used to estimate lattice strain in the PVP-ZnO nanocomposite. The dominated peaks in XRD spectra and Williamson- Hall diagrams were considered and the nano crystallite strain was plotted by drawing strain slopes. The obtained results showed that hybrid nanocomposites synthesized at 150ºC have lower strain and therefore higher yield strain. The SEM image indicated that nanoparticles are distributed uniformly.Isfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695715320191126Study of the coherent propagation of charged leptons coming from pion and W decay in Bohmian mechanicsStudy of the coherent propagation of charged leptons coming from pion and W decay in Bohmian mechanics283289114810.18869/acadpub.ijpr.15.3.283FAHAzizakramM MEttefaghi0000-0002-8062-5523S VMousaviJournal Article20191126Although charged leptons, contrary to neutrinos, cannot oscillate, exploring whether a coherent superposition of charged lepton states can change to others during the propagation is an important problem in the neutrino oscillation theory. In this paper, we consider electrons and muons coming from the pions and W decays and study their propagation in relativistic Bohmian quantum mechanics. We find out that the Bohmian trajectories of them are separated after atomic distance propagations. In fact, the computed Bohmian trajectories of electrons and muons coming from W and pion decays show that Bohmin results are consistent with those of standard quantum mechanics.Although charged leptons, contrary to neutrinos, cannot oscillate, exploring whether a coherent superposition of charged lepton states can change to others during the propagation is an important problem in the neutrino oscillation theory. In this paper, we consider electrons and muons coming from the pions and W decays and study their propagation in relativistic Bohmian quantum mechanics. We find out that the Bohmian trajectories of them are separated after atomic distance propagations. In fact, the computed Bohmian trajectories of electrons and muons coming from W and pion decays show that Bohmin results are consistent with those of standard quantum mechanics.Isfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695715320191126Ab-initio study of Ag-chain adsorbed on graphene sheetAb-initio study of Ag-chain adsorbed on graphene sheet291298114910.18869/acadpub.ijpr.15.3.291FAHSalehiMMoaddeliPAmiriJournal Article20191126In this paper, the long-range Van Der Walls dispersion force correction (vdW-DF) for a combined system consisting of an Ag-chain adsorbed on a monolayer of graphene is studied. Calculations are based on density functional theory (DFT) performed by using various LDA, PBE and BLYP approximations. Since Ag chain is weakly adsorbed on graphene sheet, the Van Der Waals contribution to the total adsorption energy cannot be ignored. When applying this correction, the structural and electronic properties of the combined system such as adsorption energy, adsorption distance, and the Fermi level shift with respect to the Dirac point are significantly affected. The weak hybridization of the electronic states of silver and carbon at the interface gives rise to a small band gap opening at the Dirac point.In this paper, the long-range Van Der Walls dispersion force correction (vdW-DF) for a combined system consisting of an Ag-chain adsorbed on a monolayer of graphene is studied. Calculations are based on density functional theory (DFT) performed by using various LDA, PBE and BLYP approximations. Since Ag chain is weakly adsorbed on graphene sheet, the Van Der Waals contribution to the total adsorption energy cannot be ignored. When applying this correction, the structural and electronic properties of the combined system such as adsorption energy, adsorption distance, and the Fermi level shift with respect to the Dirac point are significantly affected. The weak hybridization of the electronic states of silver and carbon at the interface gives rise to a small band gap opening at the Dirac point.Isfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695715320191126Effects of finite size on tera Hertz radiation of a superconductor mediaEffects of finite size on tera Hertz radiation of a superconductor media299303115010.18869/acadpub.ijpr.15.3.299FAMHosseiniJournal Article20191126The Tera hertz radiation from a finite size superconductor media inside a magnetic field has been investigated. The tera hertz radiation is due to the flux flow motion inside the media. The electromagnetic fields inside the superconductor due to fluxons are calculated and using those fields, the radiation is obtained. In this research, the effects of finite size on the radiated power and signal mean width are investigated. The results show that by increasing the superconductor thickness, the peak values of harmonics increase and the mean width decreases.The Tera hertz radiation from a finite size superconductor media inside a magnetic field has been investigated. The tera hertz radiation is due to the flux flow motion inside the media. The electromagnetic fields inside the superconductor due to fluxons are calculated and using those fields, the radiation is obtained. In this research, the effects of finite size on the radiated power and signal mean width are investigated. The results show that by increasing the superconductor thickness, the peak values of harmonics increase and the mean width decreases.Isfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695715320191126Mammographic image enhancement using wavelet transform and homomorphic filterMammographic image enhancement using wavelet transform and homomorphic filter305310115110.18869/acadpub.ijpr.15.3.305FAFMajidiA MLatifJMalakoutiHKasayiJournal Article20191126Mammography is the most effective method for the early diagnosis of breast cancer diseases. As mammographic images contain low signal to noise ratio and low contrast, it becomes too difficult for radiologists to analyze mammogram. To deal with the above stated problems, it is very important to enhance the mammographic images using image processing methods. This paper introduces a new image enhancement approach for mammographic images which uses the modified mathematical morphology, wavelet transform and homomorphic filter to suppress the noise of images. For performance evaluation of the proposed method, contrast improvement index (CII) and edge preservation index (EPI) are adopted. Experimental results on mammographic images from Pejvak Digital Imaging Center (PDIC) show that the proposed algorithm improves the two indexes, thereby achieving the goal of enhancing mammographic images.Mammography is the most effective method for the early diagnosis of breast cancer diseases. As mammographic images contain low signal to noise ratio and low contrast, it becomes too difficult for radiologists to analyze mammogram. To deal with the above stated problems, it is very important to enhance the mammographic images using image processing methods. This paper introduces a new image enhancement approach for mammographic images which uses the modified mathematical morphology, wavelet transform and homomorphic filter to suppress the noise of images. For performance evaluation of the proposed method, contrast improvement index (CII) and edge preservation index (EPI) are adopted. Experimental results on mammographic images from Pejvak Digital Imaging Center (PDIC) show that the proposed algorithm improves the two indexes, thereby achieving the goal of enhancing mammographic images.Isfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695715320191126Effect of increasing length on the electronic transport of an armchair graphene nano-ribbonsEffect of increasing length on the electronic transport of an armchair graphene nano-ribbons311315115210.18869/acadpub.ijpr.15.3.311FAShAghamiri EsfahaniMSedaghatniaJournal Article20191126In this research, we have investigated the effect of increasing length on the electronic transport of an armchair graphene nano-ribbons with nitrogen atom impurity and without impurity. The semi-infinite, one-dimensional molecular systems are connected to two electrodes and the electron-electron interaction is ignored. The system is described by a simple tight binding model. All calculations are based on the Green's function and Landauer–Buttiker approach, and the electrodes are described in a wide band approximation.In this research, we have investigated the effect of increasing length on the electronic transport of an armchair graphene nano-ribbons with nitrogen atom impurity and without impurity. The semi-infinite, one-dimensional molecular systems are connected to two electrodes and the electron-electron interaction is ignored. The system is described by a simple tight binding model. All calculations are based on the Green's function and Landauer–Buttiker approach, and the electrodes are described in a wide band approximation.Isfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695715320191126Tripartite entanglement of bosonic systems in a noninertial frame beyond the single- mode approximationTripartite entanglement of bosonic systems in a noninertial frame beyond the single- mode approximation317335115310.18869/acadpub.ijpr.15.3.317FAMSoltaniAJavaheriMHadiJournal Article20191126In this work, we generalize the entanglement of three-qbit Bosonic systems beyond the single-mode approximation when one of the observers is accelerated. For this purpose, we review the effects of acceleration on field modes and quantum states. The single-mode approximation and beyond the single-mode approximation methods are introduced. After this brief introduction, the main problem of this paper, tripartite entanglement of bosonic systems in a noninertial frame beyond the single- mode approximation is investigated. The tripartite entangled states have different classes with GHZ and W states being most important. Here, we choose &pi-tangle as a measure of tripartite entanglement. If the three parties share GHZ state, the corresponding &pi-tangle will increase by increasing acceleration for some Unruh modes. This phenomenon, increasing entanglement, has never been observed in the single-mode approximation for bosonic case. Moreover, the &pi-tangle dose not exhibit a monotonic behavior with increasing acceleration. In the infinite acceleration limit, the &pi-tangle goes to different nonzero values for distinct Unruh modes. Unlike GHZ state, the entanglement of the W state shows only monotonically increasing and decreasing behaviors with increasing acceleration. Also, the entanglement for all possible choices of Unruh modes approaches only 0.176 in the high acceleration limit. Therefore, according to the quantum entanglement, there is no distinction between the single-mode approximation and beyond the single-mode approximation methods in this limit.In this work, we generalize the entanglement of three-qbit Bosonic systems beyond the single-mode approximation when one of the observers is accelerated. For this purpose, we review the effects of acceleration on field modes and quantum states. The single-mode approximation and beyond the single-mode approximation methods are introduced. After this brief introduction, the main problem of this paper, tripartite entanglement of bosonic systems in a noninertial frame beyond the single- mode approximation is investigated. The tripartite entangled states have different classes with GHZ and W states being most important. Here, we choose &pi-tangle as a measure of tripartite entanglement. If the three parties share GHZ state, the corresponding &pi-tangle will increase by increasing acceleration for some Unruh modes. This phenomenon, increasing entanglement, has never been observed in the single-mode approximation for bosonic case. Moreover, the &pi-tangle dose not exhibit a monotonic behavior with increasing acceleration. In the infinite acceleration limit, the &pi-tangle goes to different nonzero values for distinct Unruh modes. Unlike GHZ state, the entanglement of the W state shows only monotonically increasing and decreasing behaviors with increasing acceleration. Also, the entanglement for all possible choices of Unruh modes approaches only 0.176 in the high acceleration limit. Therefore, according to the quantum entanglement, there is no distinction between the single-mode approximation and beyond the single-mode approximation methods in this limit.Isfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695715320191126An investigation into crystalline phases and nano structural and mechanical properties of HH heat resistant stainless steelsAn investigation into crystalline phases and nano structural and mechanical properties of HH heat resistant stainless steels337341115410.18869/acadpub.ijpr.15.3.337FAMHosseiniABahariFAhmadianJournal Article20191126In the present work, the effects of different casting parameters including pouring temperature and cooling rate on stainless steel structures and mechanical properties of heat resistant alloy (HH) were studied. Mo nanoparticles were synthesized through sol-gel method and were coated on the stainless steel device using spin-coating method. The effect of coating layer on the device was studied by using XRD (X-Ray Diffraction) and FT-IR (Fourier Transform Infra red ) and SEM (Scanning Electron Microscopy) techniques. The obtained results indicated an enhancement of corrosion, surface abrasion protection without changing metal surface structure, and a reduction of leakage current through the stainless steel device. Furthermore, pouring temperature and cooling rate increase caused a fine grain structure to be acquired with less carbides and better distribution in the austenitic matrix.In the present work, the effects of different casting parameters including pouring temperature and cooling rate on stainless steel structures and mechanical properties of heat resistant alloy (HH) were studied. Mo nanoparticles were synthesized through sol-gel method and were coated on the stainless steel device using spin-coating method. The effect of coating layer on the device was studied by using XRD (X-Ray Diffraction) and FT-IR (Fourier Transform Infra red ) and SEM (Scanning Electron Microscopy) techniques. The obtained results indicated an enhancement of corrosion, surface abrasion protection without changing metal surface structure, and a reduction of leakage current through the stainless steel device. Furthermore, pouring temperature and cooling rate increase caused a fine grain structure to be acquired with less carbides and better distribution in the austenitic matrix.Isfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695715320191126Investigation of the non-linear magnetic reconnection in solar chromosphereInvestigation of the non-linear magnetic reconnection in solar chromosphere343343115510.18869/acadpub.ijpr.15.3.343FAZFazelJournal Article20191126In order to see the occurrence of magnetic reconnection in the solar chromosphere, we investigate the behavior of non-linear perturbations on the magneto hydro dynamic (MHD) equations. Numericalstudy of the resistive tearing instability in a current sheet is presented by considering the MHD framework.To do this, the four field model is applied. It is shown based on the simulation that the non-linear terms make the reconnection occur faster during the spicule life time in the chromosphere.In order to see the occurrence of magnetic reconnection in the solar chromosphere, we investigate the behavior of non-linear perturbations on the magneto hydro dynamic (MHD) equations. Numericalstudy of the resistive tearing instability in a current sheet is presented by considering the MHD framework.To do this, the four field model is applied. It is shown based on the simulation that the non-linear terms make the reconnection occur faster during the spicule life time in the chromosphere.Isfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695715320191126Interaction between F2 gas with the pristine and 3C-doped(4, 4) armchair boron phosphide nanotubes: a DFT studyInteraction between F2 gas with the pristine and 3C-doped(4, 4) armchair boron phosphide nanotubes: a DFT study344344115610.18869/acadpub.ijpr.15.3.344FAMRezaei-SametiE ADadfarJournal Article20191126In this research, the structure, quantum and NQR (Nuclear quadrupole resonance)parameters of F2 gas adsorption on the pristine and 3C-doped (4,4) armchair models of boron phosphide nanotubes (BPNTs) have been investigated in the framework of density functional theory. For this purpose, at the first step, four models for F2 adsorption on the inner and outer surfaces of pristine and 3C-doped BPNTS are considered and then all structures are optimized by using Gaussian 03 program package. The optimized structures are used to calculate the quantum and NQR parameters. The calculated results reveal that the adsorption energy of pristine and 3C-doped models of BPNTs are exothermic and adsorption process is a physisorption process due to the weak Van der Waals interaction. The substitution of three carbons with three B atoms of nanotube decreases significantly the adsorption energies. The F2 adsorption and 3C-doping decrease the band gap, global hardness, and ionization potential of the pristine BPNTs. The calculated NQR parameters of all the models show that CQ and &etaQ values of the first layer are larger than those of the other layers.In this research, the structure, quantum and NQR (Nuclear quadrupole resonance)parameters of F2 gas adsorption on the pristine and 3C-doped (4,4) armchair models of boron phosphide nanotubes (BPNTs) have been investigated in the framework of density functional theory. For this purpose, at the first step, four models for F2 adsorption on the inner and outer surfaces of pristine and 3C-doped BPNTS are considered and then all structures are optimized by using Gaussian 03 program package. The optimized structures are used to calculate the quantum and NQR parameters. The calculated results reveal that the adsorption energy of pristine and 3C-doped models of BPNTs are exothermic and adsorption process is a physisorption process due to the weak Van der Waals interaction. The substitution of three carbons with three B atoms of nanotube decreases significantly the adsorption energies. The F2 adsorption and 3C-doping decrease the band gap, global hardness, and ionization potential of the pristine BPNTs. The calculated NQR parameters of all the models show that CQ and &etaQ values of the first layer are larger than those of the other layers.Isfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-695715320191126Ultra-fast spectroscopy investigation of Verwey transition in magnetiteUltra-fast spectroscopy investigation of Verwey transition in magnetite345345115710.18869/acadpub.ijpr.15.3.345FAAMokhtariJ RNealH JBlytheG AGehringJournal Article20191126Magnetite has a different electrical resistance behavior with temperatures below and above the Verwey temperature. Here, we report on Verwey transition in Fe3O4 by means of the frequency-doubled output from the Ti-sapphire laser in pump-probe experiments and from the insulator to metal transition observed by changing the temperature at the wavelength 370nm (~3.36 eV) both for pump and probe. We observed a clear difference below and above the Verwey temperature in ultra-fast transmission changes.Magnetite has a different electrical resistance behavior with temperatures below and above the Verwey temperature. Here, we report on Verwey transition in Fe3O4 by means of the frequency-doubled output from the Ti-sapphire laser in pump-probe experiments and from the insulator to metal transition observed by changing the temperature at the wavelength 370nm (~3.36 eV) both for pump and probe. We observed a clear difference below and above the Verwey temperature in ultra-fast transmission changes.