Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 16 4 2019 11 26 Nanomagnetism Nanomagnetism 251 272 1211 10.18869/acadpub.ijpr.16.4.251 FA B Aslibeiki P Kameli H Salamati Journal Article 2019 11 26 Nanomagnetism is a branch of nanotechnology, which studies the magnetic properties of nanoparticles. Single-domain superparamagnetim, superferromagnetism and superspin glasses are different magnetic states which have been observed in a system of nanoparticles. Each of these magnetic states has unique features which determines the application range of magnetic nanoparticles assembly. Shell of nanoparticles is composed of canted spins while the core spins are almost regular. Study of nanoparticles system needs to explore and characterize several features, including different anisotropies, interactions between the particles, relaxation times, coercivity, remanent magnetization, saturation magnetization and etc. Researchers have made great efforts to characterize magnetic nanoparticles. Investigations in nanomagnetism field increases by developing the application range of nanoparticles in industry, medicine and daily life Nanomagnetism is a branch of nanotechnology, which studies the magnetic properties of nanoparticles. Single-domain superparamagnetim, superferromagnetism and superspin glasses are different magnetic states which have been observed in a system of nanoparticles. Each of these magnetic states has unique features which determines the application range of magnetic nanoparticles assembly. Shell of nanoparticles is composed of canted spins while the core spins are almost regular. Study of nanoparticles system needs to explore and characterize several features, including different anisotropies, interactions between the particles, relaxation times, coercivity, remanent magnetization, saturation magnetization and etc. Researchers have made great efforts to characterize magnetic nanoparticles. Investigations in nanomagnetism field increases by developing the application range of nanoparticles in industry, medicine and daily life nanoparticles superparamagnetism AC susceptibility interactions Henkel plot
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 16 4 2019 11 26 Evaluating the performance of graphene with structural defect and functionalized by –C6H4 as an electrode active material for supercapacitors Evaluating the performance of graphene with structural defect and functionalized by –C6H4 as an electrode active material for supercapacitors 273 281 1212 10.18869/acadpub.ijpr.16.4.273 FA S M Mousavi-Khoshdel M Safi Rahmanifar E Targholi Journal Article 2019 11 26 In this study, quantum capacitance of graphene-based electrodes is evaluated using Density Functional Theory (DFT) calculations. The obtained results showed that quantum capacitance of graphene-based supercapacitors could be significantly improved by existence of structural defects on the graphene sheets at sufficiently high concentrations because of creating impure states resulted from carbon p < /font>z orbitals involved in defect. In another section of calculations, quantum capacitance of functionalized graphene with –C6H4, is evaluated. The obtained results of calculations showed that functionalized graphene with this functional group have a very good capacitance in comparison with pristine graphene, especially at smaller voltages of less than -1.0 V or greater than 1.0 V. Hybrid configurations between structural defects and functional group of –C6H4 was also studied. In general, the results indicated that the combined configuration shows higher capacity than pristine graphene In this study, quantum capacitance of graphene-based electrodes is evaluated using Density Functional Theory (DFT) calculations. The obtained results showed that quantum capacitance of graphene-based supercapacitors could be significantly improved by existence of structural defects on the graphene sheets at sufficiently high concentrations because of creating impure states resulted from carbon p < /font>z orbitals involved in defect. In another section of calculations, quantum capacitance of functionalized graphene with –C6H4, is evaluated. The obtained results of calculations showed that functionalized graphene with this functional group have a very good capacitance in comparison with pristine graphene, especially at smaller voltages of less than -1.0 V or greater than 1.0 V. Hybrid configurations between structural defects and functional group of –C6H4 was also studied. In general, the results indicated that the combined configuration shows higher capacity than pristine graphene supercapacitor functionalized graphene DFT calculations quantum capacitance
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 16 4 2019 11 26 Measurement of deuteron beam polarization before and after acceleration Measurement of deuteron beam polarization before and after acceleration 283 290 1213 10.18869/acadpub.ijpr.16.4.283 FA A Ramazani Moghaddam Arani M Hoseini Journal Article 2019 11 26 Beam polarization measurement in scattering experiments with a high accuracy and the lowest possible cost is an important issue. In this regard, deuteron beam polarization was measured in the low-energy beam line easily with a relatively low cost procedure and in a very short time by Lamb Shift Polarimeter (LSP). Also, the beam polarization has been measured in high-energy beam line with BINA. In low-energy line, a polarized beam of deuterons delivered by POLIS was decelerated and focused on LSP detection system. Three resonances between 52mT and 63mT show the distribution of different spin states of polarized deuteron beam. In high-energy beam line, polarization can be measured employing BINA via the H(d,d)p reaction. The asymmetry ratio, was obtained as a function of azimuthal angle, φ, for several polar scattering angles. Knowing values of the analyzing powers, the ratio has been used to extract the polarization results. The obtained results show that polarization of deuteron beam that is accelerated up to the energy of 130 MeV is almost the same before and after acceleration Beam polarization measurement in scattering experiments with a high accuracy and the lowest possible cost is an important issue. In this regard, deuteron beam polarization was measured in the low-energy beam line easily with a relatively low cost procedure and in a very short time by Lamb Shift Polarimeter (LSP). Also, the beam polarization has been measured in high-energy beam line with BINA. In low-energy line, a polarized beam of deuterons delivered by POLIS was decelerated and focused on LSP detection system. Three resonances between 52mT and 63mT show the distribution of different spin states of polarized deuteron beam. In high-energy beam line, polarization can be measured employing BINA via the H(d,d)p reaction. The asymmetry ratio, was obtained as a function of azimuthal angle, φ, for several polar scattering angles. Knowing values of the analyzing powers, the ratio has been used to extract the polarization results. The obtained results show that polarization of deuteron beam that is accelerated up to the energy of 130 MeV is almost the same before and after acceleration nuclear spin polarization Lamb-shift polarimeter cross-section analyzing power elastic scattering
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 16 4 2019 11 26 Effect of voltage shape of electrical power supply on radiation and density of a cold atmospheric argon plasma jet Effect of voltage shape of electrical power supply on radiation and density of a cold atmospheric argon plasma jet 291 303 1214 10.18869/acadpub.ijpr.16.4.291 FA F Sohbatzadeh M Bagheri S Motallebi Journal Article 2019 11 26 In this work, we investigated generating argon cold plasma jet at atmospheric pressure based on dielectric barrier discharge configuration using three electrical power supplies of sinusoidal, pulsed and saw tooth high voltage shapes at 8 KHZ. At first; we describe the electronic circuit features for generating high voltage (HV) wave forms including saw tooth, sinusoidal and pulsed forms. Then, we consider the effect of voltage shape on the electrical breakdown. Relative concentrations of chemical reactive species such as Oxygen, atomic Nitrogen and OH were measured using optical emission spectroscopy. Using a simple numerical model, we showed a HV with less rise time increases electron density, therefore a cold plasma jet can be produced with a minimal consumption electrical power In this work, we investigated generating argon cold plasma jet at atmospheric pressure based on dielectric barrier discharge configuration using three electrical power supplies of sinusoidal, pulsed and saw tooth high voltage shapes at 8 KHZ. At first; we describe the electronic circuit features for generating high voltage (HV) wave forms including saw tooth, sinusoidal and pulsed forms. Then, we consider the effect of voltage shape on the electrical breakdown. Relative concentrations of chemical reactive species such as Oxygen, atomic Nitrogen and OH were measured using optical emission spectroscopy. Using a simple numerical model, we showed a HV with less rise time increases electron density, therefore a cold plasma jet can be produced with a minimal consumption electrical power dielectric barrier discharge atmospheric pressure cold plasma atmospheric plasma jet
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 16 4 2019 11 26 Quantum input-output relations for lossy and anisotropic multilayer magnetodielectric meta-material Quantum input-output relations for lossy and anisotropic multilayer magnetodielectric meta-material 305 318 1215 10.18869/acadpub.ijpr.16.4.305 FA M Hoseinzadeh E Amooghorban 0000-0003-4035-0366 A Mahdifar Journal Article 2019 11 26 In this paper, we quantize electromagnetic field in, lossy, dispersive and anisotropic magnetodielectric media by using phenomenological approach. We obtain quantum input– output relations for anisotropic multilayer metamaterials. As an application of our approach, we investigate the dissipative and anisotropic effects of an anisotropic magnetodielectric slab on the quantum properties of incident input states. For this purpose, quadrature squeezing and Mandel parameter of output states has been calculated by modeling the anisotropic magnetodielectric slab through Lorentz model for a situation in which the incident states on the right and left side of the magnetodielectric slab are two- mode coherent states and quantum vacuum state, respectively In this paper, we quantize electromagnetic field in, lossy, dispersive and anisotropic magnetodielectric media by using phenomenological approach. We obtain quantum input– output relations for anisotropic multilayer metamaterials. As an application of our approach, we investigate the dissipative and anisotropic effects of an anisotropic magnetodielectric slab on the quantum properties of incident input states. For this purpose, quadrature squeezing and Mandel parameter of output states has been calculated by modeling the anisotropic magnetodielectric slab through Lorentz model for a situation in which the incident states on the right and left side of the magnetodielectric slab are two- mode coherent states and quantum vacuum state, respectively multilayer metamaterial quantization of electromagnetic field Anisotropy quadrature squeezing and Mandel parameter
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 16 4 2019 11 26 The effect of annealing temperature on electrical and optical properties of transparent and conductive thin films fabicated of multi-walled carbon nanotube/Ag nanowires The effect of annealing temperature on electrical and optical properties of transparent and conductive thin films fabicated of multi-walled carbon nanotube/Ag nanowires 319 326 1216 10.18869/acadpub.ijpr.16.4.319 FA A Zilaee M Farbod 0000-0002-9774-705X Journal Article 2019 11 26 Transparent and conductive thin films of multi-walled carbon nanotube/ Ag nanowires were fabricated using spin coating technique. In order to improve the electrical conductivity and the optical properties, the layers were annealed from room temperature to 350 °C for 30 minutes. The measurements revealed that annealing caused electrical conductivity of fabricated thin layes to be improved. The optimum annealing temperature for improving these properties was deduced 285 °C. For all different film thicknesses from about 89 to 183 nm it was observed that the presence of nanowires has improved the film’s electrical conductivity in all tempretures. The best ratio of DC conductivity to optical conductivity of the films, which is accounted as films figure of merit, was measured at 285 °C for all Ag percentages. Sheet resistance and optical transmittance were measured by four-point probe technique and UV-Vis spectrophotometer, respectively Transparent and conductive thin films of multi-walled carbon nanotube/ Ag nanowires were fabricated using spin coating technique. In order to improve the electrical conductivity and the optical properties, the layers were annealed from room temperature to 350 °C for 30 minutes. The measurements revealed that annealing caused electrical conductivity of fabricated thin layes to be improved. The optimum annealing temperature for improving these properties was deduced 285 °C. For all different film thicknesses from about 89 to 183 nm it was observed that the presence of nanowires has improved the film’s electrical conductivity in all tempretures. The best ratio of DC conductivity to optical conductivity of the films, which is accounted as films figure of merit, was measured at 285 °C for all Ag percentages. Sheet resistance and optical transmittance were measured by four-point probe technique and UV-Vis spectrophotometer, respectively sheet resistance thin film figure of merit four-point probe UV-Vis spectrophotometer
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 16 4 2019 11 26 The effect of four-spin exchanges on the honeycomb lattice diagram phase of S=3/2 J1-J2 Antiferromagnetic Heisenberg model The effect of four-spin exchanges on the honeycomb lattice diagram phase of S=3/2 J1-J2 Antiferromagnetic Heisenberg model 327 333 1217 10.18869/acadpub.ijpr.16.4.327 FA F Keshavarz H Mosadeq Journal Article 2019 11 26 In this study, the effect of four-spin exchanges between the nearest and next nearest neighbor spins of honeycomb lattice on the phase diagram of S=3/2 antiferomagnetic Heisenberg model is considered with two-spin exchanges between the nearest and next nearest neighbor spins. Firstly, the method is investigated with classical phase diagram. In classical phase diagram, in addition to Neel order, classical degeneracy is also seen. The existance of this phase in diagram phase is important because of the probability of the existence of quantum spin liquid in this region for such amount of interaction. To investigate the effect of quantum fluctuation on the stability of the obtained classical phase diagram, linear spin wave theory has been used. Obtained results show that in classical degeneracy regime, the quantum fluctuations cause the order by disorder in the spin system and the ground state is ordered In this study, the effect of four-spin exchanges between the nearest and next nearest neighbor spins of honeycomb lattice on the phase diagram of S=3/2 antiferomagnetic Heisenberg model is considered with two-spin exchanges between the nearest and next nearest neighbor spins. Firstly, the method is investigated with classical phase diagram. In classical phase diagram, in addition to Neel order, classical degeneracy is also seen. The existance of this phase in diagram phase is important because of the probability of the existence of quantum spin liquid in this region for such amount of interaction. To investigate the effect of quantum fluctuation on the stability of the obtained classical phase diagram, linear spin wave theory has been used. Obtained results show that in classical degeneracy regime, the quantum fluctuations cause the order by disorder in the spin system and the ground state is ordered Heisenberg model Neel order classical degeneracy quantum spin liquid
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 16 4 2019 11 26 Effect of fission fragment on thermal conductivity via electrons with an energy about 0.5 MeV in fuel rod gap Effect of fission fragment on thermal conductivity via electrons with an energy about 0.5 MeV in fuel rod gap 335 343 1218 10.18869/acadpub.ijpr.16.4.335 FA F Golian A Pazirandeh S Mohammadi 0000-0001-7706-9856 Journal Article 2019 11 26 The heat transfer process from pellet to coolant is one of the important issues in nuclear reactor. In this regard, the fuel to clad gap and its physical and chemical properties are effective factors on heat transfer in nuclear fuel rod discussion. So, the energy distribution function of electrons with an energy about 0.5 MeV in fuel rod gap in Busherhr’s VVER-1000 nuclear reactor was investigated in this paper. Also, the effect of fission fragments such as Krypton, Bromine, Xenon, Rubidium and Cesium on the electron energy distribution function as well as the heat conduction via electrons in the fuel rod gap have been studied. For this purpose, the Fokker- Planck equation governing the stochastic behavior of electrons in absorbing gap element has been applied in order to obtain the energy distribution function of electrons. This equation was solved via Runge-Kutta numerical method. On the other hand, the electron energy distribution function was determined by using Monte Carlo GEANT4 code. It was concluded that these fission fragments have virtually insignificant effect on energy distribution of electrons and therefore, on thermal conductivity via electrons in the fuel to clad gap. It is worth noting that this result is consistent with the results of other experiments. Also, it is shown that electron relaxation in gap leads to decrease in thermal conductivity via electrons The heat transfer process from pellet to coolant is one of the important issues in nuclear reactor. In this regard, the fuel to clad gap and its physical and chemical properties are effective factors on heat transfer in nuclear fuel rod discussion. So, the energy distribution function of electrons with an energy about 0.5 MeV in fuel rod gap in Busherhr’s VVER-1000 nuclear reactor was investigated in this paper. Also, the effect of fission fragments such as Krypton, Bromine, Xenon, Rubidium and Cesium on the electron energy distribution function as well as the heat conduction via electrons in the fuel rod gap have been studied. For this purpose, the Fokker- Planck equation governing the stochastic behavior of electrons in absorbing gap element has been applied in order to obtain the energy distribution function of electrons. This equation was solved via Runge-Kutta numerical method. On the other hand, the electron energy distribution function was determined by using Monte Carlo GEANT4 code. It was concluded that these fission fragments have virtually insignificant effect on energy distribution of electrons and therefore, on thermal conductivity via electrons in the fuel to clad gap. It is worth noting that this result is consistent with the results of other experiments. Also, it is shown that electron relaxation in gap leads to decrease in thermal conductivity via electrons Fokker-Planck equation thermal conductivity Electron energy distribution function fission fragment
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 16 4 2019 11 26 Semi-analytical calculation of fuel parameters for shock ignition fusion Semi-analytical calculation of fuel parameters for shock ignition fusion 345 350 1219 10.18869/acadpub.ijpr.16.4.345 FA S A Ghasemi A H Farahbod S Sobhanian 0000-0002-2695-2400 Journal Article 2019 11 26 In this paper, semi-analytical relations of total energy, fuel gain and hot-spot radius in a non-isobaric model have been derived and compared with Schmitt (2010) numerical calculations for shock ignition scenario. in nuclear fusion. Results indicate that the approximations used by Rosen (1983) and Schmitt (2010) for the calculation of burn up fraction have not enough accuracy compared with numerical simulation. Meanwhile, it is shown that the obtained formulas of non-isobaric model cannot determine the model parameters of total energy, fuel gain and hot-spot radius uniquely. Therefore, employing more appropriate approximations, an improved semianalytical relations for non-isobaric model has been presented, which  are in a better agreement with numerical calculations of shock ignition by Schmitt (2010). In this paper, semi-analytical relations of total energy, fuel gain and hot-spot radius in a non-isobaric model have been derived and compared with Schmitt (2010) numerical calculations for shock ignition scenario. in nuclear fusion. Results indicate that the approximations used by Rosen (1983) and Schmitt (2010) for the calculation of burn up fraction have not enough accuracy compared with numerical simulation. Meanwhile, it is shown that the obtained formulas of non-isobaric model cannot determine the model parameters of total energy, fuel gain and hot-spot radius uniquely. Therefore, employing more appropriate approximations, an improved semianalytical relations for non-isobaric model has been presented, which  are in a better agreement with numerical calculations of shock ignition by Schmitt (2010). non-isobaric model shock ignition fast-shock ignition
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 16 4 2019 11 26 Investigating the growth rate in a free-electron laser with a laser wiggler and plasma background Investigating the growth rate in a free-electron laser with a laser wiggler and plasma background 351 358 1220 10.18869/acadpub.ijpr.16.4.351 FA N Esmaeildoost S Jafari Journal Article 2019 11 26 In this paper, a free-electron laser (FEL) growth rate with a laser wiggler in which plasma background is used to generate short wavelengths in x-ray regimes, has been investigated theoretically. A linearly polarized laser pulse, due to having short wiggler periods (inrange) is able to produce coherent radiations in x-ray regions and can be applied as a planar wiggler in a FEL. Phase velocity of the laser pulse in presence of plasma background decreases. In this case, the electron beam can be in synchronism with the laser pulse and enters the interaction region with less energy which leads to producing x-ray pulses by low enegy beams, without requiring high beam energies. This configuration allows obtaining higher frequencies than conventional FELs (with magnetostatic wigglers) for a device. Employing a perturbation  analysis for the momentum transfer, continuity, and Maxwell equations, the dispersion relation for system has been derived  and the effect of plasma density variation on growth rate of a free electron laser with a laser wiggler and plasma background has been discussed. In addition, cross section of electron trajectories for different values of axial magnetic field has been simulated by using fourth order Runge-Kutta method. Results shows that by increasing plasma density, growth rate for group  and decreases, while for group  increases In this paper, a free-electron laser (FEL) growth rate with a laser wiggler in which plasma background is used to generate short wavelengths in x-ray regimes, has been investigated theoretically. A linearly polarized laser pulse, due to having short wiggler periods (inrange) is able to produce coherent radiations in x-ray regions and can be applied as a planar wiggler in a FEL. Phase velocity of the laser pulse in presence of plasma background decreases. In this case, the electron beam can be in synchronism with the laser pulse and enters the interaction region with less energy which leads to producing x-ray pulses by low enegy beams, without requiring high beam energies. This configuration allows obtaining higher frequencies than conventional FELs (with magnetostatic wigglers) for a device. Employing a perturbation  analysis for the momentum transfer, continuity, and Maxwell equations, the dispersion relation for system has been derived  and the effect of plasma density variation on growth rate of a free electron laser with a laser wiggler and plasma background has been discussed. In addition, cross section of electron trajectories for different values of axial magnetic field has been simulated by using fourth order Runge-Kutta method. Results shows that by increasing plasma density, growth rate for group  and decreases, while for group  increases free-electron laser growth rate dispersion relation plasma background
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 16 4 2019 11 26 Synthesis and characterization of iron oxide nanoparticles using electrical discharge in solution Synthesis and characterization of iron oxide nanoparticles using electrical discharge in solution 359 364 1221 10.18869/acadpub.ijpr.16.4.359 FA B Mohammadi A A Ashkarran M Mahmoudi Journal Article 2019 11 26 Iron oxide nanoparticles were synthesized for the first time using electrical arc discharge between a pair of highly pure titanium electrode without using metallic iron electrodes in iron chloride salt solution. The produced nanoparticles were characterized using various analyses such as X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). XRD and XPS analyses showed formation of α-Fe2O3 phase. Microscopic studies on the obtained samples revealed formation of rice like iron oxide nanostructures at 10 minutes of electrical discharge which changed to semi-spherical shape after calcination at 600 oC for 2 hours. The results of Dynamic Light Scattering (DLS) analysis demonstrated formation of 24 nm particles with almost narrow distribution of 11nm, which are increased in size and distribution width by heat treatment. The obtained results verify the potential ability of this technique to achieve monodispersed iron oxide nanoparticles with narrow distribution in a very short time Iron oxide nanoparticles were synthesized for the first time using electrical arc discharge between a pair of highly pure titanium electrode without using metallic iron electrodes in iron chloride salt solution. The produced nanoparticles were characterized using various analyses such as X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). XRD and XPS analyses showed formation of α-Fe2O3 phase. Microscopic studies on the obtained samples revealed formation of rice like iron oxide nanostructures at 10 minutes of electrical discharge which changed to semi-spherical shape after calcination at 600 oC for 2 hours. The results of Dynamic Light Scattering (DLS) analysis demonstrated formation of 24 nm particles with almost narrow distribution of 11nm, which are increased in size and distribution width by heat treatment. The obtained results verify the potential ability of this technique to achieve monodispersed iron oxide nanoparticles with narrow distribution in a very short time nanoparticles iron oxide electrical discharge solution
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 16 4 2019 11 26 The effect of pH on the structural and magnetic properties of PbFe12O19 nanoparticles prepared by sol-gel method The effect of pH on the structural and magnetic properties of PbFe12O19 nanoparticles prepared by sol-gel method 365 374 1222 10.18869/acadpub.ijpr.16.4.365 FA S E Mousavi Ghahfarokhi Z Araghi Rostami I Kazeminezhad Journal Article 2019 11 26 In this research, lead hexaferrites nanoparticles (PbFe12O19) were prepared by sol-gel method. The effect of pH on the structural and magnetic properties of PbFe12O19 was studied. The attempt in this paper was to depict the effect of change in sol-gel pH on the size and morphology of the samples as well as their structural and magnetic properties. Therefore, samples with pH = 1.8, 3, 5, 6, 7, and 8 were prepared. Then, the dry gels of the samples were heated in the optimum annealing temperature and time of 800 oC and 3 h, respectively. In order to study the structural, morphological and magnetic properties of the samples prepared in various pHs X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Vibration Sample Magnetometer (VSM), and LCR meter were applied, respectively In this research, lead hexaferrites nanoparticles (PbFe12O19) were prepared by sol-gel method. The effect of pH on the structural and magnetic properties of PbFe12O19 was studied. The attempt in this paper was to depict the effect of change in sol-gel pH on the size and morphology of the samples as well as their structural and magnetic properties. Therefore, samples with pH = 1.8, 3, 5, 6, 7, and 8 were prepared. Then, the dry gels of the samples were heated in the optimum annealing temperature and time of 800 oC and 3 h, respectively. In order to study the structural, morphological and magnetic properties of the samples prepared in various pHs X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Vibration Sample Magnetometer (VSM), and LCR meter were applied, respectively pH nanoparticles lead hexaferitte XRD VSM SEM
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 16 4 2019 11 26 Determination of the dead layer and full-energy peak efficiency of an HPGe detector using the MCNP code and experimental results Determination of the dead layer and full-energy peak efficiency of an HPGe detector using the MCNP code and experimental results 375 381 1223 10.18869/acadpub.ijpr.16.4.375 FA M Moeinifar A Shirani KH Rahmani Journal Article 2019 11 26 One important factor in using an High Purity Germanium (HPGe) detector is its efficiency that highly depends on the geometry and absorption factors, so that when the configuration of source-detector geometry is changed, the detector efficiency must be re-measured. The best way of determining the efficiency of a detector is measuring the efficiency of standard sources. But considering the fact that standard sources are hardly available and it is time consuming to find them, determinig the efficiency by simulation which gives enough efficiency in less time, is important. In this study, the dead layer thickness and the full-energy peak efficiency of an HPGe detector was obtained by Monte Carlo simulation, using MCNPX code. For this, we first measured gamma–ray spectra for different sources placed at various distances from the detector and stored the measured spectra obtained. Then the obtained spectra were simulated under similar conditions in vitro.At first, the whole volume of germanium was regarded as active, and the obtaind spectra from calculation were compared with the corresponding experimental spectra. Comparison of the calculated spectra with the measured spectra showed considerable differences. By making small variations in the dead layer thickness of the detector (about a few hundredths of a millimeter) in the simulation program, we tried to remove these differences and in this way a dead layer of 0.57 mm was obtained for the detector. By incorporating this value for the dead layer in the simulating program, the full-energy peak efficiency of the detector was then obtained both by experiment and by simulation, for various sources at various distances from the detector, and both methods showed good agreements. Then, using MCNP code and considering the exact measurement system, one can conclude that the efficiency of an HPGe detector for various source-detector geometries can be calculated with rather good accuracy by simulation method without any need for performing any experiment One important factor in using an High Purity Germanium (HPGe) detector is its efficiency that highly depends on the geometry and absorption factors, so that when the configuration of source-detector geometry is changed, the detector efficiency must be re-measured. The best way of determining the efficiency of a detector is measuring the efficiency of standard sources. But considering the fact that standard sources are hardly available and it is time consuming to find them, determinig the efficiency by simulation which gives enough efficiency in less time, is important. In this study, the dead layer thickness and the full-energy peak efficiency of an HPGe detector was obtained by Monte Carlo simulation, using MCNPX code. For this, we first measured gamma–ray spectra for different sources placed at various distances from the detector and stored the measured spectra obtained. Then the obtained spectra were simulated under similar conditions in vitro.At first, the whole volume of germanium was regarded as active, and the obtaind spectra from calculation were compared with the corresponding experimental spectra. Comparison of the calculated spectra with the measured spectra showed considerable differences. By making small variations in the dead layer thickness of the detector (about a few hundredths of a millimeter) in the simulation program, we tried to remove these differences and in this way a dead layer of 0.57 mm was obtained for the detector. By incorporating this value for the dead layer in the simulating program, the full-energy peak efficiency of the detector was then obtained both by experiment and by simulation, for various sources at various distances from the detector, and both methods showed good agreements. Then, using MCNP code and considering the exact measurement system, one can conclude that the efficiency of an HPGe detector for various source-detector geometries can be calculated with rather good accuracy by simulation method without any need for performing any experiment HPGe detector dead layer MCNP code full-energy peak efficiency
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 16 4 2019 11 26 Phase properties of a double-periodic quasi-crystal composed of single-negative materials Phase properties of a double-periodic quasi-crystal composed of single-negative materials 383 388 1224 10.18869/acadpub.ijpr.16.4.383 FA Rashidi 0000-0001-5944-3226 Roshan Entezar Journal Article 2019 11 26 In this paper, the phase properties of waves reflected from one-dimensional double-periodic quasi-crystals consisting of single-negative materials are investigated using transfer matrix method. It is observed that, by increasing the double-periodic generation number, a large omnidirectional band gap is created in the single-nagative frequency range. We limit our studies to the frequency range of this wide band phase compensator gap.The results show that  the value of phase difference between TE-polarized and TM-polarized waves reflected from this band gap, is independent from generation number in a wide band frequency range. Also, the reflection phase difference increases by increasing the incident angle, and in the central parts of the gap remains almost constant. Fourthermore, at two points near the edges of the gap, the value of the phase difference keeps almost zero in spite of the change of incident angle. Based on these properties, this structure can be used as a wide band phase compensator, an omnidirectional synchronous reflector, and a polarizer In this paper, the phase properties of waves reflected from one-dimensional double-periodic quasi-crystals consisting of single-negative materials are investigated using transfer matrix method. It is observed that, by increasing the double-periodic generation number, a large omnidirectional band gap is created in the single-nagative frequency range. We limit our studies to the frequency range of this wide band phase compensator gap.The results show that  the value of phase difference between TE-polarized and TM-polarized waves reflected from this band gap, is independent from generation number in a wide band frequency range. Also, the reflection phase difference increases by increasing the incident angle, and in the central parts of the gap remains almost constant. Fourthermore, at two points near the edges of the gap, the value of the phase difference keeps almost zero in spite of the change of incident angle. Based on these properties, this structure can be used as a wide band phase compensator, an omnidirectional synchronous reflector, and a polarizer : phase double-periodic quasi-crystal single-negative phase compensator omni-directionally synchronous reflector polarizer
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 16 4 2019 11 26 Singlet particles as cold dark matter in θ-exact non-commutative space-time Singlet particles as cold dark matter in θ-exact non-commutative space-time 389 392 1225 10.18869/acadpub.ijpr.16.4.389 FA S A A Alavi T Salehi Journal Article 2019 11 26 First, singlet dark matter annihilation into pair charged fermions and pair  bosons was studied to the first order of non-commutativity parameter in perturbative model. Our results are different from the results reported in some previous studies. Then the problem is formulated in -exact non-commutative space-time and non-perturbative model, then the exact results are presented First, singlet dark matter annihilation into pair charged fermions and pair  bosons was studied to the first order of non-commutativity parameter in perturbative model. Our results are different from the results reported in some previous studies. Then the problem is formulated in -exact non-commutative space-time and non-perturbative model, then the exact results are presented Dark matter singlet fermion singlet scalar non-commutative space-time
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 16 4 2019 11 26 Nonlinear optical properties measurement of polypyrrole -carbon nanotubes prepared by an electrochemical polymerization method Nonlinear optical properties measurement of polypyrrole -carbon nanotubes prepared by an electrochemical polymerization method 393 398 1226 10.18869/acadpub.ijpr.16.4.393 FA Shahriari Ghasemi Varnamkhasti Journal Article 2019 11 26 In this work, the optical properties dependence of Multi-Walled Carbon Nanotubes (MWNT) on concentration was discussed. MWNT samples were prepared in polypyrrole by an electrochemical polymerization of monomers, in the presence of different concentrations of MWNTs, using Sodium Dodecyl-Benzen-Sulfonate (SDBS) as surfactant at room temperature. The nonlinear refractive and nonlinear absorbtion indices were measured using a low power CW laser beam operated at 532 nm using z-scan method. The results show that nonlinear refractive and nonlinear absorbtion indices tend to be increased with increasing the concentration of carbon nanotubes. Optical properties of  carbone nanotubes indicate that they are good candidates for nonlinear optical devices In this work, the optical properties dependence of Multi-Walled Carbon Nanotubes (MWNT) on concentration was discussed. MWNT samples were prepared in polypyrrole by an electrochemical polymerization of monomers, in the presence of different concentrations of MWNTs, using Sodium Dodecyl-Benzen-Sulfonate (SDBS) as surfactant at room temperature. The nonlinear refractive and nonlinear absorbtion indices were measured using a low power CW laser beam operated at 532 nm using z-scan method. The results show that nonlinear refractive and nonlinear absorbtion indices tend to be increased with increasing the concentration of carbon nanotubes. Optical properties of  carbone nanotubes indicate that they are good candidates for nonlinear optical devices carbon nanotubes nonlinear refractive index nonlinear absorption index z-scan method