https://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Measuring Destructive effects of gamma radiation on the physical properties of steelMeasuring Destructive effects of gamma radiation on the physical properties of steel369377136610.29252/ijpr.18.3.369FAZAmirsardariM RAbdiJournal Article20191126In the present study, the most useful stainless steels of in nuclear industry, i.e. 304, 304L and 316L were provided and laser cut into 0.5*0.5 cm dimension. The effect of radiation on physical properties of samples were investigated. Gamma irradiation on samples was done with a 60Co radioisotope to the doses of 100 and 200 kGy. The resistance of the samples was measured through the Four-Probe technique, and also the special resistance and the electrical conductivity of the samples were measured from resistance. The conductivity of the samples was obtained through Widman-Frantz. The magnetic properties of the samples were also measured by the Vibrating Sample Magnetometer. In the present study, the most useful stainless steels of in nuclear industry, i.e. 304, 304L and 316L were provided and laser cut into 0.5*0.5 cm dimension. The effect of radiation on physical properties of samples were investigated. Gamma irradiation on samples was done with a 60Co radioisotope to the doses of 100 and 200 kGy. The resistance of the samples was measured through the Four-Probe technique, and also the special resistance and the electrical conductivity of the samples were measured from resistance. The conductivity of the samples was obtained through Widman-Frantz. The magnetic properties of the samples were also measured by the Vibrating Sample Magnetometer. https://ijpr.iut.ac.ir/article_1366_6e0c39570e110ade8676ec88ffe7499d.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Elastic scattering of 15N ions by 12C at 23 MeVElastic scattering of 15N ions by 12C at 23 MeV379389136710.29252/ijpr.18.3.379FAHNanakarOKakueeJournal Article20191126Scattering of 15N ions with the energy of Elab = 23 MeV on the CH2(Au) target is investigated. Elastic scattering of these ions in the angular range of 7°-19° was measured by employing the silicon strip detector, “LEDA”. Using the measured scattering data, deviation of ion beam, number of incident ions on the target and differential cross sections of the 12C(15N, 15N)12C elastic scattering in the angular range of 7°-19° were determined. Moreover, by applying the optical model and using the Fresco software, the scattering cross sections in the angular range of 0°-60° in the laboratory framework were obtained by entering the extrapolated optical parameters. The obtained cross section data were then compared with the experimental ones. The theoretical cross section data resulting from the optical potential exhibit meaningful difference with the experimental data obtained in this research work in the covered angular range. Scattering of 15N ions with the energy of Elab = 23 MeV on the CH2(Au) target is investigated. Elastic scattering of these ions in the angular range of 7°-19° was measured by employing the silicon strip detector, “LEDA”. Using the measured scattering data, deviation of ion beam, number of incident ions on the target and differential cross sections of the 12C(15N, 15N)12C elastic scattering in the angular range of 7°-19° were determined. Moreover, by applying the optical model and using the Fresco software, the scattering cross sections in the angular range of 0°-60° in the laboratory framework were obtained by entering the extrapolated optical parameters. The obtained cross section data were then compared with the experimental ones. The theoretical cross section data resulting from the optical potential exhibit meaningful difference with the experimental data obtained in this research work in the covered angular range. https://ijpr.iut.ac.ir/article_1367_7eccda9e2c79fe30924c3b788e5bae5a.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Design and fabrication of a heterodyne electrooptic modulator in lithium niobateDesign and fabrication of a heterodyne electrooptic modulator in lithium niobate391400136810.29252/ijpr.18.3.391FAHDehghan NayeriRAsadiMKhajeJournal Article20191126In this research, design and fabrication of an integrated heterodyne electrooptic modulator in lithium niobate have been presented. In this modulator, the waveguide is made by using proton exchange process; to exert two high frequency signals, deposited electrodes with Mach-Zender arms between them are used. In this method, every electrical signal is applied on one of the Mach-Zender arms, so that it can be stimulated by one specific frequency; these two signals are united optically to create frequencies equal to sum and subtraction of the input signal frequencies in the output. Also, by using finite element method, the influence of proton diffusion scale in the output light mode, electrode dimension, and configuration in the overlap integral of the light mode and electrical field, as well as electrode impedance, is estimated.In this research, design and fabrication of an integrated heterodyne electrooptic modulator in lithium niobate have been presented. In this modulator, the waveguide is made by using proton exchange process; to exert two high frequency signals, deposited electrodes with Mach-Zender arms between them are used. In this method, every electrical signal is applied on one of the Mach-Zender arms, so that it can be stimulated by one specific frequency; these two signals are united optically to create frequencies equal to sum and subtraction of the input signal frequencies in the output. Also, by using finite element method, the influence of proton diffusion scale in the output light mode, electrode dimension, and configuration in the overlap integral of the light mode and electrical field, as well as electrode impedance, is estimated.https://ijpr.iut.ac.ir/article_1368_2c032bf0011fae94e0371b399c20fbf2.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126The effect of magnetic nickel nanowires structural parameterson the electrodeposition efficiencyThe effect of magnetic nickel nanowires structural parameterson the electrodeposition efficiency401407136910.29252/ijpr.18.3.401FAAJokarARamazaniJournal Article20191126In this work, magnetic Ni nanowire arrays were ac-pulse electrodeposited into the anodic aluminum oxide (AAO) template fabricated by the common two-step anodization technique. The barrier layers at the bottom of the pores were exponentially thinned in a non-equilibrium anodization process to 8, 12, 16 and 20 V. These were fabricated using the constant of 15 mA deposition current, 48 mS off-time between pulses, 10, 20 substrate temperatures, and 30°C electrolyte temperature. The effects of thinning voltage and substrate temperature on the electrodeposition efficiency and the magnetic quality of the Ni nanowires were investigated by a Vibrating sample magnetometer (VSM) and a scanning electron microscope (SEM). In this paper, we realized that the bed temperature of 10°C, by increasing the thickness of the barrier layer, reduced deposition efficiency and the temperature was 20 degrees backfired.
In this work, magnetic Ni nanowire arrays were ac-pulse electrodeposited into the anodic aluminum oxide (AAO) template fabricated by the common two-step anodization technique. The barrier layers at the bottom of the pores were exponentially thinned in a non-equilibrium anodization process to 8, 12, 16 and 20 V. These were fabricated using the constant of 15 mA deposition current, 48 mS off-time between pulses, 10, 20 substrate temperatures, and 30°C electrolyte temperature. The effects of thinning voltage and substrate temperature on the electrodeposition efficiency and the magnetic quality of the Ni nanowires were investigated by a Vibrating sample magnetometer (VSM) and a scanning electron microscope (SEM). In this paper, we realized that the bed temperature of 10°C, by increasing the thickness of the barrier layer, reduced deposition efficiency and the temperature was 20 degrees backfired.
https://ijpr.iut.ac.ir/article_1369_15ad78b7553c037070ece92d0f89dc7a.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126A numerical study of the effect of the number of turns of coil on the heat produced in the induction heating process in the 3d modelA numerical study of the effect of the number of turns of coil on the heat produced in the induction heating process in the 3d model408419137010.29252/ijpr.18.3.408FAA JShokriM HTavakoliASabouri DodaranM SAkhondi KhezrabadJournal Article20191126Computer modeling for the design of inductors for different applications in the induction heating process often seems to be necessary to save costs caused by the trial and error. In this paper, the effects of the number of loops in the induction heating process with the numerical solution of the Maxwell equations have been investigated using finite element method (FEM) and the COMSOL MULTIPHYSICS software package in three dimensions. Therefore, considering the effect of the number of coil turns on the amount and pattern of heat produced in the workpiece for special applications in the industry and technology is critical. This is because the number of coil turns is one of the important parameters in the design of induction heating systems. At first, a single turn coil is simulated in a three-dimensional model; then multi-turn coils with the turns number 2, 3, and 4 have been considered. The voltage of 200 V with the frequency of 1 KHz has been used, as applied to the coil, to serve as the source of electromagnetic fields. The results of numerical calculations show that the number of coil turns can have a significant effect on quantities such as distribution and intensity of magnetic flux density, eddy currents density in the workpiece, and the volume of heat produced in the coil and workpiece.Computer modeling for the design of inductors for different applications in the induction heating process often seems to be necessary to save costs caused by the trial and error. In this paper, the effects of the number of loops in the induction heating process with the numerical solution of the Maxwell equations have been investigated using finite element method (FEM) and the COMSOL MULTIPHYSICS software package in three dimensions. Therefore, considering the effect of the number of coil turns on the amount and pattern of heat produced in the workpiece for special applications in the industry and technology is critical. This is because the number of coil turns is one of the important parameters in the design of induction heating systems. At first, a single turn coil is simulated in a three-dimensional model; then multi-turn coils with the turns number 2, 3, and 4 have been considered. The voltage of 200 V with the frequency of 1 KHz has been used, as applied to the coil, to serve as the source of electromagnetic fields. The results of numerical calculations show that the number of coil turns can have a significant effect on quantities such as distribution and intensity of magnetic flux density, eddy currents density in the workpiece, and the volume of heat produced in the coil and workpiece.https://ijpr.iut.ac.ir/article_1370_94082ad50239901dd10509891b83abb8.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Raising flux pinning by Ni substitution in YBa2Cu3O7-Î´Raising flux pinning by Ni substitution in YBa2Cu3O7-Î´421425137110.29252/ijpr.18.3.421FABHadisichaniHShakeripourHSalamatiJournal Article20191126The high-Tc Y1-xNixBa2Cu3O7-δ samples doped by Ni for Y atom, with x=0, 0.002, 0.004, 0.006 and 0.01 were synthesized by the standard solid-state reaction method. The XRD diffraction of samples showed no impurity phase in all samples. Magnetic susceptibility of the samples under two different magnetic fields of 0.8 and 400 A/m was measured. The results showed that by increasing nickel element to an optimum value, the intragranular connection and flux pinning were improved.The high-Tc Y1-xNixBa2Cu3O7-δ samples doped by Ni for Y atom, with x=0, 0.002, 0.004, 0.006 and 0.01 were synthesized by the standard solid-state reaction method. The XRD diffraction of samples showed no impurity phase in all samples. Magnetic susceptibility of the samples under two different magnetic fields of 0.8 and 400 A/m was measured. The results showed that by increasing nickel element to an optimum value, the intragranular connection and flux pinning were improved.https://ijpr.iut.ac.ir/article_1371_0875f445c633f1dc5bdd9e0aef89449e.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Investigation of pulse width effect on structural and optical properties of molybdenum oxide thin films deposited by HiPIMSInvestigation of pulse width effect on structural and optical properties of molybdenum oxide thin films deposited by HiPIMS427435137210.29252/ijpr.18.3.427FAHNajafi-AshtianiJournal Article20191126In this study, molybdenum oxide thin films are deposited by using high power impulse magnetic sputtering (HiPIMS) at different pulses length of 60, 90, 120, 150 and 180 μs on glass substrates in a combination of reactive and non-reactive gases with a ratio of O2/Ar = 0.66. The structural and optical properties of these coatings are studied. The chemical composition of these metal oxides is determined by analyzing X-ray photoelectron spectroscopy (XPS), and are determined by MoOx stoichiometry with different x-values. By studying the optical properties, it is found that the oxygen deficiency with increasing pulse width cause to reduce the average of optical transmittance and also decrease the optical band gap of coatings.In this study, molybdenum oxide thin films are deposited by using high power impulse magnetic sputtering (HiPIMS) at different pulses length of 60, 90, 120, 150 and 180 μs on glass substrates in a combination of reactive and non-reactive gases with a ratio of O2/Ar = 0.66. The structural and optical properties of these coatings are studied. The chemical composition of these metal oxides is determined by analyzing X-ray photoelectron spectroscopy (XPS), and are determined by MoOx stoichiometry with different x-values. By studying the optical properties, it is found that the oxygen deficiency with increasing pulse width cause to reduce the average of optical transmittance and also decrease the optical band gap of coatings.https://ijpr.iut.ac.ir/article_1372_655fec4ccdf7bc54d1aa20da55ac91b8.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Calculation of the Cluster Emission Half-Lives by Considering the Deformations and Relative Orientations of the NucleiCalculation of the Cluster Emission Half-Lives by Considering the Deformations and Relative Orientations of the Nuclei437443137310.29252/ijpr.18.3.437FAPNazarzadehRBagheriJournal Article20191126In this paper, the cluster emission half-lives have been calculated by using the WKB approximation and the proximity potential Prox77 as the nuclear potential part and considering the deformations and different relative orientations of the cluster and daughter nuclei. The calculated results are in good agreement with the experimental data and the results of the Liquid Drop Model, LDM. It is seen that with increasing the angle of the relative orientation, the systems under consideration, will be more stable against this phenomenon.In this paper, the cluster emission half-lives have been calculated by using the WKB approximation and the proximity potential Prox77 as the nuclear potential part and considering the deformations and different relative orientations of the cluster and daughter nuclei. The calculated results are in good agreement with the experimental data and the results of the Liquid Drop Model, LDM. It is seen that with increasing the angle of the relative orientation, the systems under consideration, will be more stable against this phenomenon.https://ijpr.iut.ac.ir/article_1373_ef15e7ac755baf8871bc0fef028ef053.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Dynamical study of emitted particles from exited nucleus using Langevin approachDynamical study of emitted particles from exited nucleus using Langevin approach445450137410.29252/ijpr.18.3.445FADNaderiAFarmaniJournal Article20191126Using Langevin dynamics and the dissipative nature of the fission process, we have studied dynamical variations of nucleus from the formation of the compound nucleus to separation stage of two fission fragments. During this dissipative process, particles such as neutron, proton, alpha particle and gamma ray emit from the compound system. In the present work, the number of emitted particles using Langevin equation are calculated, dynamically. Obtained results for emitted alpha particles, protons and neutrons are compared with the experimental data. Also, we have studied the influence of the dissipative coefficient on these quantities. These results show that the dissipative coefficient affects the results, as well as the good agreement between the experimental data and theoretical results can be reproduced by using the dynamical approach.
Using Langevin dynamics and the dissipative nature of the fission process, we have studied dynamical variations of nucleus from the formation of the compound nucleus to separation stage of two fission fragments. During this dissipative process, particles such as neutron, proton, alpha particle and gamma ray emit from the compound system. In the present work, the number of emitted particles using Langevin equation are calculated, dynamically. Obtained results for emitted alpha particles, protons and neutrons are compared with the experimental data. Also, we have studied the influence of the dissipative coefficient on these quantities. These results show that the dissipative coefficient affects the results, as well as the good agreement between the experimental data and theoretical results can be reproduced by using the dynamical approach.
https://ijpr.iut.ac.ir/article_1374_bea3fd7df118436702de5e73ee05db7c.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Effect of Coupling Constant Correction on Equilibration TimeEffect of Coupling Constant Correction on Equilibration Time451457137510.29252/ijpr.18.3.451FAHEbrahimMAli-AkbariJournal Article20191126We use gauge-gravity duality to study the effect of corrections to the coupling constant on equilibration time in field theory for scalar operators with Delta=2,3. We will show that for larger correction in coupling constant the equilibration time enhances and this behavior is independent of the method we use to make the system out of equilibrium. Interestingly we observe that for fast energy injection the rescaled equilibration time is independent of temperature of field theory.
We use gauge-gravity duality to study the effect of corrections to the coupling constant on equilibration time in field theory for scalar operators with Delta=2,3. We will show that for larger correction in coupling constant the equilibration time enhances and this behavior is independent of the method we use to make the system out of equilibrium. Interestingly we observe that for fast energy injection the rescaled equilibration time is independent of temperature of field theory.
https://ijpr.iut.ac.ir/article_1375_c2823304078fc4b69477c6958aa11086.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Enhancement of terahertz radiation from laser-bunched electron beam in a helical wiggler with axial magnetic fieldEnhancement of terahertz radiation from laser-bunched electron beam in a helical wiggler with axial magnetic field459465137610.29252/ijpr.18.3.459FAPGomarAHasanbeigiHMehdianJournal Article20191126The generation of coherent Terahertz (THz) radiation is studied which is produced from moving the relativistic electron beam through a helical wiggler with axial magnetic field. The relativistic electron beam is modulated via interacts with the beat wave of two laser beams that have frequency difference in THz range. When the modulated relativistic beam of electrons go through the helical wiggler with axial magnetic field, it radiates coherent THz electromagnetic wave as an antenna. In addition, the numerical study has shown the maximum THz power increases with the increasing axial magnetic field power.The generation of coherent Terahertz (THz) radiation is studied which is produced from moving the relativistic electron beam through a helical wiggler with axial magnetic field. The relativistic electron beam is modulated via interacts with the beat wave of two laser beams that have frequency difference in THz range. When the modulated relativistic beam of electrons go through the helical wiggler with axial magnetic field, it radiates coherent THz electromagnetic wave as an antenna. In addition, the numerical study has shown the maximum THz power increases with the increasing axial magnetic field power.https://ijpr.iut.ac.ir/article_1376_333f350e48607cb6618f1e26f1791849.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Investigation of electrostatic potential of a helical biomolecule in the Debye-Huckel regime by considering the dielectric inhomogeneityInvestigation of electrostatic potential of a helical biomolecule in the Debye-Huckel regime by considering the dielectric inhomogeneity467475137710.29252/ijpr.18.3.467FAARezaie DereshgiFMohammad-RafieeJournal Article20191126Inside living cells, many essential processes involve deformations of charged helical molecules and the interactions between them. Actin filaments and DNA molecules are important examples of charged helical molecules. In this paper, we consider an impermeable double stranded charged molecule in the solvent. According to the nature, the dielectric constant of the molecule is considerably different from that of the bulk. In order to calculate the electrostatic potential in the problem in the Debye-Huckel regime, we find the proper Debye-Huckel Green function for the problem. Using this Green function, we calculate the electrostatic potential in the system. Furthermore, we study the dependence of the electrostatic potential on the dielectric inhomogeneity, structural parameters and the salt concentration. This study could shed some light on the role of electrostatic interactions in many essential processes involving charged helical molecules such as actin filaments and DNA moleculesInside living cells, many essential processes involve deformations of charged helical molecules and the interactions between them. Actin filaments and DNA molecules are important examples of charged helical molecules. In this paper, we consider an impermeable double stranded charged molecule in the solvent. According to the nature, the dielectric constant of the molecule is considerably different from that of the bulk. In order to calculate the electrostatic potential in the problem in the Debye-Huckel regime, we find the proper Debye-Huckel Green function for the problem. Using this Green function, we calculate the electrostatic potential in the system. Furthermore, we study the dependence of the electrostatic potential on the dielectric inhomogeneity, structural parameters and the salt concentration. This study could shed some light on the role of electrostatic interactions in many essential processes involving charged helical molecules such as actin filaments and DNA moleculeshttps://ijpr.iut.ac.ir/article_1377_586be345231b535837a2f382c67c0002.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Passively Q-switched LED-pumped Ce: Nd:YAG laserPassively Q-switched LED-pumped Ce: Nd:YAG laser477484137810.29252/ijpr.18.3.477FAMTarkashvandA HFarahbodS AHashemizadehJournal Article20191126The experimental study of passively Q-switched, LED-pumped Ce:Nd:YAG laser is reported. The active medium is a 3 mm diameter laser rod with 60 mm length; it is optically pumped with four segments of blue LEDs at 460 nm, with each segment consisting of 32 single LEDs. The 14 cm length optical resonator with 2 dielectric mirrors and the reflectivity of 99 and 93 percent at 1064 nm produced more than 200 micro-joules laser spikes at the free-running mode of operation. By using a passive optical switch with 96% initial transmission and 0.6 J electrical pumping energy, the single Q-switch (QS) laser pulse with 240 ns pulse-width and 17 micro-joules optical energy was produced. By increasing the pumping energy to 1.2 J, two nearly similar QS laser pulses were generated. Moreover, we have proposed a method for decreasing the pulse-width and increasing the energy of single QS laser pulse that is based on controlling the pumping rate by shaping the current of LEDsThe experimental study of passively Q-switched, LED-pumped Ce:Nd:YAG laser is reported. The active medium is a 3 mm diameter laser rod with 60 mm length; it is optically pumped with four segments of blue LEDs at 460 nm, with each segment consisting of 32 single LEDs. The 14 cm length optical resonator with 2 dielectric mirrors and the reflectivity of 99 and 93 percent at 1064 nm produced more than 200 micro-joules laser spikes at the free-running mode of operation. By using a passive optical switch with 96% initial transmission and 0.6 J electrical pumping energy, the single Q-switch (QS) laser pulse with 240 ns pulse-width and 17 micro-joules optical energy was produced. By increasing the pumping energy to 1.2 J, two nearly similar QS laser pulses were generated. Moreover, we have proposed a method for decreasing the pulse-width and increasing the energy of single QS laser pulse that is based on controlling the pumping rate by shaping the current of LEDshttps://ijpr.iut.ac.ir/article_1378_caa388182ec979f34ffb5530f0bf5dc2.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Quantum generalization of the Appleton- Hartree formulationQuantum generalization of the Appleton- Hartree formulation485489137910.29252/ijpr.18.3.485FABRajabiAMehramizJournal Article20191126Abstract
The purpose of this paper is to present a new generalized form of the Appleton-Hartree formulation. To that end, we use a system of linearized quantum plasma equations to include quantum corrections due to the quantum force produced by the density fluctuations of electrons. Dispersion relations and their modifications resulting form quantum effects are derived for both quasi-parallel and quasi- perpendicular wave modes. In comparison to the previous studies, the results show that quantum effects modify the dispersion of the whistler, helicon, left-handed, ordinary and extraordinary waves. Furthermore, the analysis of results, in particular cases, confirms those of previous studies and, in limiting cases, leads to known relationships in classical plasma physics.Abstract
The purpose of this paper is to present a new generalized form of the Appleton-Hartree formulation. To that end, we use a system of linearized quantum plasma equations to include quantum corrections due to the quantum force produced by the density fluctuations of electrons. Dispersion relations and their modifications resulting form quantum effects are derived for both quasi-parallel and quasi- perpendicular wave modes. In comparison to the previous studies, the results show that quantum effects modify the dispersion of the whistler, helicon, left-handed, ordinary and extraordinary waves. Furthermore, the analysis of results, in particular cases, confirms those of previous studies and, in limiting cases, leads to known relationships in classical plasma physics.https://ijpr.iut.ac.ir/article_1379_f505203f3db6a8d94ba69037857c6126.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Carbon K edge structures of molecular crystals from first-principles: A comparison between phenanthrene and anthraceneCarbon K edge structures of molecular crystals from first-principles: A comparison between phenanthrene and anthracene490490138010.29252/ijpr.18.3.490FAHNejatipourMDadsetaniJournal Article20191126By means of ab-initio calculations on the basis of the FPLAPW method, we compared the energy loss near edge structure (ELNES) of carbon K edges in crystalline phenanthrene and its isomer, anthracene. In these two organic compounds, different non-equivalent carbon atoms can result in distinct K edge spectra due to the different carbon-carbon bond lengths, as a characteristic behavior of the molecular crystals. The smaller bond lengths push the ELNES features to the higher energies. In anthracene, the energy position of the edge-onset appears at lower energies due to its smaller electronic band gap. At the onset of the C K edge of anthracene, the strong splitting of the π* peak into two peaks is observable. Compared to the C K edge in anthracene, due to the slightly larger C–C bond length in phenanthrene, the peak position of the main σ structure has a red shift. The ELNES spectrum of crystalline phenanthrene includes electron transition of 1s carbon orbital to π* and σ* states. In anthracene, the first two intense features have contributions of π* orbitals. Consideration of the core-hole approximation by means of super-cells and the collection of semi-angles at magic value are essential to obtain reasonable ELNES spectra.By means of ab-initio calculations on the basis of the FPLAPW method, we compared the energy loss near edge structure (ELNES) of carbon K edges in crystalline phenanthrene and its isomer, anthracene. In these two organic compounds, different non-equivalent carbon atoms can result in distinct K edge spectra due to the different carbon-carbon bond lengths, as a characteristic behavior of the molecular crystals. The smaller bond lengths push the ELNES features to the higher energies. In anthracene, the energy position of the edge-onset appears at lower energies due to its smaller electronic band gap. At the onset of the C K edge of anthracene, the strong splitting of the π* peak into two peaks is observable. Compared to the C K edge in anthracene, due to the slightly larger C–C bond length in phenanthrene, the peak position of the main σ structure has a red shift. The ELNES spectrum of crystalline phenanthrene includes electron transition of 1s carbon orbital to π* and σ* states. In anthracene, the first two intense features have contributions of π* orbitals. Consideration of the core-hole approximation by means of super-cells and the collection of semi-angles at magic value are essential to obtain reasonable ELNES spectra.https://ijpr.iut.ac.ir/article_1380_72a46e40af112e11a57cb007d4f7325a.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Effect of ultrasonic waves on morphology and electrical treatment of grapheneEffect of ultrasonic waves on morphology and electrical treatment of graphene491491138110.29252/ijpr.18.3.491FARSabet DarianiRBakhshandehHHaghiJournal Article20191126It is important to examine the factors that determine the properties of graphene. Various factors affect the properties of graphene nanosheets that can revolutionize the use of graphene. One such factor is ultrasonic waves, which have significant effects on graphene properties. In this research, we studied the effect of ultrasonic waves with different power levels (35, 50, 360, and 420 W) on four graphene samples. in this research all the samples fabricated by electrochemical exfoliation. In this method, ammonium sulfate nonorganic salt was used for producing solution and used electrodes PT and graphite where +10 volt was applied to the electrodes Ultrasonic waves are used to homogenize the electrolyte for samples. And samples were analyzed using scanning electron microscope (SEM) imaging and Fourier transform infrared spectroscopy (FTIR) spectroscopy to determine their structure and electrical properties. The I-V curves of the samples were measured after spraying the glass substrate. Then, FTIR spectra and I-V characteristics were studied. Our results showed that with increasing ultrasonic power, FTIR spectra did not change, however conductivity of grown graphene increases.It is important to examine the factors that determine the properties of graphene. Various factors affect the properties of graphene nanosheets that can revolutionize the use of graphene. One such factor is ultrasonic waves, which have significant effects on graphene properties. In this research, we studied the effect of ultrasonic waves with different power levels (35, 50, 360, and 420 W) on four graphene samples. in this research all the samples fabricated by electrochemical exfoliation. In this method, ammonium sulfate nonorganic salt was used for producing solution and used electrodes PT and graphite where +10 volt was applied to the electrodes Ultrasonic waves are used to homogenize the electrolyte for samples. And samples were analyzed using scanning electron microscope (SEM) imaging and Fourier transform infrared spectroscopy (FTIR) spectroscopy to determine their structure and electrical properties. The I-V curves of the samples were measured after spraying the glass substrate. Then, FTIR spectra and I-V characteristics were studied. Our results showed that with increasing ultrasonic power, FTIR spectra did not change, however conductivity of grown graphene increases.https://ijpr.iut.ac.ir/article_1381_eb1600df4013422a2cfecfd38e7e9720.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Frequencyâdriven chaos in the electrical circuit of Duffing-Holmes oscillator and its controlFrequencyâdriven chaos in the electrical circuit of Duffing-Holmes oscillator and its control492492138210.29252/ijpr.18.3.492FAM. DMoinul IslamSBasuDHalderADeSBhattacharyaJournal Article20191126Accurate detection of weak periodic signals within noise and possibility of secure messaging have made Duffing oscillator (DO) highly important in the field of communication. Investigation on the properties of DO is thus ardently sought for. An elegant approach to accomplish the same is to fabricate electronic circuit simulating DO non-linear equation and to study the effect of input signal amplitude (Vin) and frequency (f), disentangling each other. Recently, Vin-driven chaotic dynamics was studied by constructing a simple Duffing-Holmes (DH) oscillator circuit. However, the f-driven characteristics of the oscillator remain unknown at constant Vin. The present work is based on the MATLAB simulation of f-driven chaotic dynamics of the DH equation. Similar output, mixed with chaos and non-chaos, is obtained by constructing the circuit, both in lab and PSPICE simulation. The circuit moves into complete chaos at f=270 Hz, while period-2 bifurcation appears at f=680 Hz for constant Vin 0.9V. The chaos control is also achieved by two simple methods. In the first method, the variation of circuit parameter (capacitance) induces chaos control. In the second method, synchronization is achieved by coupling two similar oscillators. These two methods, though apparently simple, could be highly beneficial for using DH in secure communication.Accurate detection of weak periodic signals within noise and possibility of secure messaging have made Duffing oscillator (DO) highly important in the field of communication. Investigation on the properties of DO is thus ardently sought for. An elegant approach to accomplish the same is to fabricate electronic circuit simulating DO non-linear equation and to study the effect of input signal amplitude (Vin) and frequency (f), disentangling each other. Recently, Vin-driven chaotic dynamics was studied by constructing a simple Duffing-Holmes (DH) oscillator circuit. However, the f-driven characteristics of the oscillator remain unknown at constant Vin. The present work is based on the MATLAB simulation of f-driven chaotic dynamics of the DH equation. Similar output, mixed with chaos and non-chaos, is obtained by constructing the circuit, both in lab and PSPICE simulation. The circuit moves into complete chaos at f=270 Hz, while period-2 bifurcation appears at f=680 Hz for constant Vin 0.9V. The chaos control is also achieved by two simple methods. In the first method, the variation of circuit parameter (capacitance) induces chaos control. In the second method, synchronization is achieved by coupling two similar oscillators. These two methods, though apparently simple, could be highly beneficial for using DH in secure communication.https://ijpr.iut.ac.ir/article_1382_a2d509feab952b2eb3ee103eb5785835.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126The electrical transport properties in ZnO bulk, ZnMgO/ZnO and ZnMgO/ZnO/ZnMgO heterostructuresThe electrical transport properties in ZnO bulk, ZnMgO/ZnO and ZnMgO/ZnO/ZnMgO heterostructures493493138310.29252/ijpr.18.3.493FAMAmirabbasiEAbdolhosseini SarsariJournal Article20191126p { margin-bottom: 0.1in; direction: rtl; line-height: 120%; text-align: right; }a:link { color: rgb(0, 0, 255); }
In this paper, the reported experimental data related to electrical transport properties in bulk ZnO, ZnMgO/ZnO and ZnMgO/ZnO/ZnMgO single and double heterostructures were analyzed quantitavely and the most important scattering parameters on controlling electron concentration and electron mobility were obtained. Treatment of intrinsic mechanisms includes polar-optical phonon scattering, piezoelectric scattering and acoustic deformation potential scattering. For extrinsic mechanisms, ionized impurity, dislocation scattering and strain induced fields are included. For bulk ZnO, the reported experimental data were corrected for removing the effects of a degenerate layer at the ZnO/sapphire interface via a two – layer Hall – effect model. Also, donor density, acceptor density and donor activation energy were determined via the charge balance equation. This sample exhibits hopping conduction below 50K and dislocation scattering controls electron mobility closely. Obtained results indicate that enhancement of electron mobility in double sample as compared with single one can be attributed to reduction of dislocation density, two dimensional impurity density in the potential well due to background impurities and/or interface charge and strain induced fields which can be related to better electron confinement in the channel and enhancement in sheet carrier concentration of 2DEG in this sample.p { margin-bottom: 0.1in; direction: rtl; line-height: 120%; text-align: right; }a:link { color: rgb(0, 0, 255); }
In this paper, the reported experimental data related to electrical transport properties in bulk ZnO, ZnMgO/ZnO and ZnMgO/ZnO/ZnMgO single and double heterostructures were analyzed quantitavely and the most important scattering parameters on controlling electron concentration and electron mobility were obtained. Treatment of intrinsic mechanisms includes polar-optical phonon scattering, piezoelectric scattering and acoustic deformation potential scattering. For extrinsic mechanisms, ionized impurity, dislocation scattering and strain induced fields are included. For bulk ZnO, the reported experimental data were corrected for removing the effects of a degenerate layer at the ZnO/sapphire interface via a two – layer Hall – effect model. Also, donor density, acceptor density and donor activation energy were determined via the charge balance equation. This sample exhibits hopping conduction below 50K and dislocation scattering controls electron mobility closely. Obtained results indicate that enhancement of electron mobility in double sample as compared with single one can be attributed to reduction of dislocation density, two dimensional impurity density in the potential well due to background impurities and/or interface charge and strain induced fields which can be related to better electron confinement in the channel and enhancement in sheet carrier concentration of 2DEG in this sample.https://ijpr.iut.ac.ir/article_1383_c60775341bbd22829d48f67e988ca55e.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Double Langmuir probe measurement of plasma parameters in a dc glow dischargeDouble Langmuir probe measurement of plasma parameters in a dc glow discharge494494138410.29252/ijpr.18.3.494FAS AGhasemiAMazandaraniSShahshenasJournal Article20191126In this paper, plasma main characteristics such as electron mean temperature, electron number density, and oscillation frequency have been measured experimentally using the double Langmuir probe diagnostic system. In our experiment, the plasma was generated by applying the low pressure dc glow discharge in several common gases. The experimental results indicated the highest plasma density and oscillation frequency for the plasma originating from Argon and the highest mean value of temperature for Hydrogen plasma. The experimental results were then confirmed by COMSOL simulator, showing reasonable consistency with the simulations. The data were then used to compare the degree of ionization with the measured plasma parameters.In this paper, plasma main characteristics such as electron mean temperature, electron number density, and oscillation frequency have been measured experimentally using the double Langmuir probe diagnostic system. In our experiment, the plasma was generated by applying the low pressure dc glow discharge in several common gases. The experimental results indicated the highest plasma density and oscillation frequency for the plasma originating from Argon and the highest mean value of temperature for Hydrogen plasma. The experimental results were then confirmed by COMSOL simulator, showing reasonable consistency with the simulations. The data were then used to compare the degree of ionization with the measured plasma parameters.https://ijpr.iut.ac.ir/article_1384_190c69d1498eabc47dad83969a54c122.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126The effect of material nonlinearity on the band gap for TE and TM modes in square and triangular latticesThe effect of material nonlinearity on the band gap for TE and TM modes in square and triangular lattices495495138510.29252/ijpr.18.3.495FAMMokari-Behbahan0000-0001-6282-1486YShahamatM HAlamatsazA ABabaei-BrojenyHMoeiniJournal Article20191126In this article, by using the method of finite difference time domain (FDTD) and PML boundary conditions, we have studied the photonic band gaps for TE and TM modes in square and triangular lattices consisting of air holes in dielectric medium and compared the results. In addition, the effect of nonlinearity of the photonic crystal background on the photonic band gaps and comparison with the results of the linear case (holes in a background medium with linear dielectric constant) has been presented. Comparison of the transmission spectrums in linear and nonlinear cases shows a red shift in minimum transmission for both triangular and square lattices.In this article, by using the method of finite difference time domain (FDTD) and PML boundary conditions, we have studied the photonic band gaps for TE and TM modes in square and triangular lattices consisting of air holes in dielectric medium and compared the results. In addition, the effect of nonlinearity of the photonic crystal background on the photonic band gaps and comparison with the results of the linear case (holes in a background medium with linear dielectric constant) has been presented. Comparison of the transmission spectrums in linear and nonlinear cases shows a red shift in minimum transmission for both triangular and square lattices.https://ijpr.iut.ac.ir/article_1385_d9b20430f4ce86b08f08c1b278ea5578.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Measurement and simulation of magnetic field strenght in the nano magnetic abrasive finishing processMeasurement and simulation of magnetic field strenght in the nano magnetic abrasive finishing process496496138610.29252/ijpr.18.3.496FAMVahdatiSRasouliJournal Article20191126Magnetic abrasive finishing can be classified as a non-traditional super finishing method for finishing surfaces with different shapes and working materials like flat plates, shafts, bearings parts, screws, tubes and many other mechanical parts that need good surface finishing properties. MAF is effective in polishing, cleaning, deburring and burnishing metal parts. The most important parameter affecting the performance of this method, such as surface roughness, is the magnetic force. The magnetic force is obtained from a permanent Magnet or a DC magnet. In this article, the magnetic field strength, magnetic flux density and magnetic force in different states are studied using simulation with some finite element method software (Maxwell). The shapes of magnets, various sizes and the material of fixture are studied. The magnetic properties of the material of the work piece are simulated too. To verify the simulation results, the situation is also measured by a Gauss meter. The intensity of the magnetic field required for the micro chipping is obtained for different geometric shapes and various materials of work piece in the magnetic abrasive finishing process. The results show that increasing the distance from the magnet surface results in a decrease in the magnetic flux density and significance of the edge phenomenon effect. The effect of work piece material, work piece fixture material, and the interaction of them were is shown to be significant on magnetic flux density. To concentrate the magnetic abrasive powder in the polishing process of non-ferromagnetic parts, the ferromagnetic fixture for these parts can be providedMagnetic abrasive finishing can be classified as a non-traditional super finishing method for finishing surfaces with different shapes and working materials like flat plates, shafts, bearings parts, screws, tubes and many other mechanical parts that need good surface finishing properties. MAF is effective in polishing, cleaning, deburring and burnishing metal parts. The most important parameter affecting the performance of this method, such as surface roughness, is the magnetic force. The magnetic force is obtained from a permanent Magnet or a DC magnet. In this article, the magnetic field strength, magnetic flux density and magnetic force in different states are studied using simulation with some finite element method software (Maxwell). The shapes of magnets, various sizes and the material of fixture are studied. The magnetic properties of the material of the work piece are simulated too. To verify the simulation results, the situation is also measured by a Gauss meter. The intensity of the magnetic field required for the micro chipping is obtained for different geometric shapes and various materials of work piece in the magnetic abrasive finishing process. The results show that increasing the distance from the magnet surface results in a decrease in the magnetic flux density and significance of the edge phenomenon effect. The effect of work piece material, work piece fixture material, and the interaction of them were is shown to be significant on magnetic flux density. To concentrate the magnetic abrasive powder in the polishing process of non-ferromagnetic parts, the ferromagnetic fixture for these parts can be providedhttps://ijpr.iut.ac.ir/article_1386_357f6a731262724f82ab92930e3745f3.pdfhttps://www.psi.ir/physics_society_iran_1_homeIranian Journal of Physics Research1682-695718320191126Bulk viscous string cosmological models in Saez â Ballester theory of gravitationBulk viscous string cosmological models in Saez â Ballester theory of gravitation497497138710.29252/ijpr.18.3.497FAV U MRaoMVijaya SanthiK V SSireeshaNSandhya RaniJournal Article20191126Spatially homogeneous Bianchi type-II, VIII and IX anisotropic, as well as isotropic cosmological models can be obtained in a scalar tensor theory of gravitation proposed by Saez and Ballester (1986) when the source for energy momentum tensor is a bulk viscous fluid containing one-dimensional cosmic strings. All the models obtained and presented here are expanding, non-rotating and accelerating. Also, some important features of the models thus obtained have been discussed.Spatially homogeneous Bianchi type-II, VIII and IX anisotropic, as well as isotropic cosmological models can be obtained in a scalar tensor theory of gravitation proposed by Saez and Ballester (1986) when the source for energy momentum tensor is a bulk viscous fluid containing one-dimensional cosmic strings. All the models obtained and presented here are expanding, non-rotating and accelerating. Also, some important features of the models thus obtained have been discussed.https://ijpr.iut.ac.ir/article_1387_7c0a711f87ce0bcbb64add584e8e1995.pdf