Monte Carlo simulation of response function of organic scintillators to gamma rays and neutrons using FLUKA, MCNPX and SCINFUL code
M
tajik
دانشگاه دامغان
author
H
Yousefnia
پژوهشگاه علوم وفنون هسته ای
author
text
article
2019
per
In organic scintillators, the energy distribution of gamma rays and neutrons is indirectly measured by the pulse height distribution of light output produced through gamma ray and neutron reactions in the detectors. Accurate estimate of the interaction of gamma and neutrons in the detector and produce charged secondary particles and subsequent scintillation light produced in the calculation of the response function is the most important. Although,, the complexity of the light generation on these scintillators makes modeling their response function difficult with standard Monte Carlo method. The paper reports generate the response function of an NE102 plastic scintillator when exposed to gamma rays and response function of a BC501A liquid scintillator to mono-energetic and Am-Be neutrons using the EVENTBIN card of the FLUKA code and the PTRAC card of the MCNPX code. The comparison between simulated and experimental response functions show that both FLUKA and MCNPX codes generated distributions are in good agreement with corresponding experimental results.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
635
645
http://ijpr.iut.ac.ir/article_1306_99f3a95a9b5c652f6981ec1dd3454df7.pdf
dx.doi.org/10.29252/ijpr.17.5.635
Generation and investigation of plasma ball and plasma jet by microwave at atmospheric pressure
F
SOHBATZADEH
گروه فیزیک اتمی و مولکولی، دانشکده علوم پایه، دانشگاه مازندران، بابلسر
author
Z
Omidi
گروه فیزیک اتمی و مولکولی، دانشکده علوم پایه، دانشگاه مازندران، بابلسر
author
N
Kashi
گروه فیزیک اتمی و مولکولی، دانشکده علوم پایه، دانشگاه مازندران، بابلسر
author
text
article
2019
per
In this work, we first produced microwave plasma ball, then changed the ball into a microwave plasma jet by flowing a working gas through a nozzle. The effect of working gas on the thermal characteristics of the plasma ball and atmospheric pressure microwave plasma jet was investigated. We used resonant absorption scheme by a metallic antenna inside a chamber in which led to the ionization of surrounded gas forming the plasma. A commercial magnetron at 2.45 GHz was used to produce plasma by various gases such as argon, nitrogen, air and argon/nitrogen composition. For analysis and identification of reactive species in the plasma, the optical spectroscopy (OES) was carried out. Optical emission spectroscopy of the plasma ball/jet revealed the presence of reactive neutral and excited atomic and molecular components generating from working gases and antenna materials. The antenna material has a significant impact on the jet length, so that maximum length of the plasma jet was observed in Fe-Ni antenna. The results of the experiments revealed that there is no significant change in the plasma jet length versus different gas flow rates and applied powers, while it is more sensitive to the gas type and antenna material.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
647
660
http://ijpr.iut.ac.ir/article_1307_bc110ffa3c42e8254bb776493d280c4b.pdf
dx.doi.org/10.29252/ijpr.17.5.647
Hair analysis by means of laser induced breakdown spectroscopy technique and support vector machine model for diagnosing addiction
M
Vahid Dastjerdi
گروه فیزیک، دانشگاه اصفهان، اصفهان
author
Z
Derakhshan Zadeh
گروه فیزیک، دانشگاه ولی عصر رفسنجان، رفسنجان
author
S J
Mousavi
گروه فیزیک، دانشگاه اصفهان، اصفهان
author
H
Ranjbar Askari
گروه فیزیک، دانشگاه ولی عصر رفسنجان، رفسنجان
author
M
Soltanolkotabi
گروه فیزیک، دانشگاه اصفهان، اصفهان
author
text
article
2019
per
Along with the development of laboratory methods for diagnosing addiction, concealment ways, either physically or chemically, for creating false results have been in progress. In this research based on the Laser Induced Breakdown Spectroscopy technique (LIBS) and analyzing hair of addicted and normal people, we are proposing a new method to overcome problems in conventional methods and reduce possibility of cheating in the process of diagnosing addiction. For this purpose, at first we have sampled hair of 17 normal and addicted people and recorded 5 spectrums for each sample, overall 170 spectrums. After analyzing the recorded LIBS spectra and detecting the atomic and ionic lines as well as molecular bands, relative intensities of emission lines for Aluminum to Calcium (Al/Ca) and Aluminum to Sodium (Al/Na) were selected as the input variables for the Support Vector Machine model (SVM).The Radial Basis, Polynomial Kernel functions and a linear function were chosen for classifying the data in SVM model. The results of this research showed that by the combination of LIBS technique and SVM one can distinguish addicted person with precision of 100%. Because of several advantages of LIBS such as high speed analysis and being portable, this method can be used individually or together with available methods as an automatic method for diagnosing addiction through hair analysis.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
661
667
http://ijpr.iut.ac.ir/article_1308_3fd8573ddb5dc2383cbf4726a2ef65e9.pdf
dx.doi.org/10.29252/ijpr.17.5.661
Mono-Z constraints on the fermionic dark matter model with pseudoscalar mediator at the LHC
K
Ghorbani
دانشگاه اراک-دانشکده علوم-گروه فیزیک
author
L
Khalkhali
دانشگاه اراک-دانشکده علوم-گروه فیزیک
author
text
article
2019
per
In this research we study the Mono-Z signature along with dark matter production at the LHC in a renormalizable dark matter model. We look at processes with L+L-+MET in the final state. We simulate signal and background events at central mass energy 14 TeV We then evaluate the LHC sensitivities for some points in the model parameter space for two integrated luminosities L=100 fb-1 and L=1 ab-1 The main goal in this investigation is to constrain the relevant Yukawa coupling taking into account the Mono-Z plus dark matter signature, Invisible Higgs decay width measurements, observed dark matter relic density and Higgs physics. We find out that there are regions in the parameter space which remain viable after applying all the constraints mentioned above.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
669
680
http://ijpr.iut.ac.ir/article_1309_f3916baee76500ccfe99a87ecba2ebee.pdf
dx.doi.org/10.29252/ijpr.17.5.669
Magnetic properties of three-dimensional magnetic topological insulators: the effects of hexagonal warping
J
Abouie
دانشگاه تحصیلات تکمیلی علوم پایه زنجان
author
M
Mogharrar Jahromi
دانشگاه تحصیلات تکمیلی علوم پایه زنجان
author
S
Abedinpour
دانشگاه تحصیلات تکمیلی علوم پایه زنجان
author
text
article
2019
per
We have investigated the magnetic properties of three-dimensional topological insulators, doped with magnetic atoms. The spin-orbit locking of surface electrons results in interesting magnetic behaviors, absent in conventional insulators without spin-orbit coupling. In particular, the ferromagnetic-paramagnetic transition temperature has a strong dependence on different system parameters. Here, using the mean-field formalism we have studied the effects of hexagonal warping on the order parameter, critical temperature, and magnetic susceptibility of system.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
681
690
http://ijpr.iut.ac.ir/article_1310_4bd5b72a85e3c9a9f436bdaca5a51706.pdf
dx.doi.org/10.29252/ijpr.17.5.681
Excitation and damping of transversal oscillation in coronal loops by wake phenomena
A
abedini
دانشگاه قم ساختمان شهید بهشتی گروه فیزیک
author
text
article
2019
per
Transversal oscillation of coronal loops that are interpreted as signatures of magneto hydrodynamics (MHD) waves are observed frequently in active region corona loops. The amplitude of this oscillation has been found to be strongly attenuated. The damping of transverse oscillation may be produced by the dissipation mechanism and the wake of the traveling disturbance. The damping of transversal loop oscillations with wake phenomena is not related to any dissipation mechanism. Also, these kinds of coronal loop oscillations are not related to the kink mode, although this mode can be occurred after the attenuation process by the energy of the wave packet deposited in the loop. In this paper the excitation and damping of transversal coronal loop oscillations with wake of traveling wave packet is discussed in detail, both theoretically and observationally. Here, the transversal coronal loop oscillations is modeled with a one dimensional simple line-tied. The dynamics of the loop and the coronal is governed by the Klein–Gordon differential equation. A localized disturbance that can be generated by nearby flare produces a perturbation that undergoes dispersion as it propagates toward the loop. As a consequence, the amplitudes of oscillates decay with time roughly t-1/2 at the external cutoff frequency. These observed data on 2016-Dec-4 by Atmospheric Imaging Assembly (AIA) onboard Solar Dynamic Observatory (SDO) observations data, consisting of 560 images with an interval of 24 seconds in the 171 A0 pass band is analyzed for evidence of excitation and damping of transverse oscillations of coronal loop that is situated near a flare. In this analyzed signatures of transverse oscillations that are damped rapidly were found, with periods in the range of P=18.5-23.85 minutes. Furthermore, oscillation of loop segments attenuate with time roughly as t-α that average values of α for 4 different loops change form 0.65-0.80. The magnitude values of α are in good agreement with theoretical prediction for damping of transverse loop oscillations by wake of the traveling wave packet that can be considered responsible for the rapid damping of the observed oscillations.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
691
697
http://ijpr.iut.ac.ir/article_1311_5a84946bc95db333a949e8abebcfa23b.pdf
dx.doi.org/10.29252/ijpr.17.5.691
Single top production as a constraint for Wï¢ boson
S
Paktinat Mehdiabadi
پژوهشگاه دانش های بنیادی
author
text
article
2019
per
The existence of a new massive charged gauge boson, known as W’, is proposed by many new physics scenarios. When W’ decays to tb, the final state is very similar to the final state of the s-channel single top production, where W boson is the off-shell mediator to produce the top and bottom quarks. If W’ exists, it can affect the cross section of the SM s-channel single top production, so measuring this cross section can constrain the W’ contribution. We use different data categories from CMS and ATLAS experiments to constrain this contribution. Assuming a pure left-handed (right-handed) W’ gives a lower limit of 1290 (1360) GeV at 95% Confidence Level on the mass of W’. If the coupling coefficient is increased to 1.8, the lower limit on the W’ mass can exceed 1900 GeV, in special cases.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
699
702
http://ijpr.iut.ac.ir/article_1312_13760a6c2b738b8057665852a6284616.pdf
dx.doi.org/10.29252/ijpr.17.5.699
Simulation of propagation of flattend Gaussian beam in strongly nonlocal nonlinear media using paraxial group transformation
Z
Roosta
دانشکده فیزیک، دانشگاه صنعتی شیراز، شیراز
author
A
Keshavarz
دانشکده فیزیک، دانشگاه صنعتی شیراز، شیراز
author
text
article
2019
per
In this paper, propagation of flattend Gaussian beam in optical media is simulated by split step fourier method, ABCD matrix method, and paraxial group method, and results are compared. For this purpose, at first, flattend Gaussian beam, strongly nonlocal nonlinear media and investigation methods of propagation of optical beams are introduced. Then, propagation of flattend Gaussian beam in free space and strongly nonlocal nonlinear media are simulated by these methods. Results show that paraxial group method can be considered as a suitable method for investigation of propagation of optical beams in an optical media.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
703
708
http://ijpr.iut.ac.ir/article_1313_18e236aeb107a24b6408147774046302.pdf
dx.doi.org/10.29252/ijpr.17.5.703
Electromagnetically induced transparency in a plasmonic system comprising of three metal-dielectric-metal parallel slabs: Plasmon- Plasmon interaction
N
Daneshfar
دانشگاه رازی کرمانشاه
author
M
Moradbeigi
دانشگاه رازی کرمانشاه
author
T
Naseri
دانشگاه رازی کرمانشاه
author
text
article
2019
per
In this paper, electromagnetically induced transparency (EIT) in a system consisting of associated arrays of parallel slabs (metal-dielectric-metal) is studied. The transmission coefficient, the reflection coefficient and the absorption coefficient as function of the incident light frequency by using the transfer matrix method is calculated and numerically discussed. Influence of the thickness of slab and the type of plasmonic metal on the induced transparency has been investigated. It is shown with decreasing the thickness of intermediate slab of length (dielectric slab), the induced transparency increases due to the strong plasmon–plasmon couplings.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
709
715
http://ijpr.iut.ac.ir/article_1314_3ef9eeb69c3e0f44e58c22c82ced6384.pdf
dx.doi.org/10.29252/ijpr.17.5.709
The effect of uniform spin-orbit coupling and uniform Zeeman magnetic field on the topological properties of one-dimensional dimerized nano wire
M
Bahari
دانشگاه زنجان
author
M V
Hosseini
دانشگاه زنجان
author
text
article
2019
per
We theoretically demonstrate the interplay of uniform spin-orbit coupling and uniform Zeeman magnetic field on the topological properties of one-dimensional double well nano wire which is known as Su-Schrieffer-Heeger (SSH) model. The system in the absence of Zeeman magnetic field and presence of uniform spin-orbit coupling exhibits topologically trivial/non–trivial insulator depending on the hopping amplitudes and spin-orbit coupling strength. Topological phases of this system can be determined by integers which are related to the Zak phase of occupied Bloch bands. In the phase diagram, there are three different regions with topologically distinct phases. The system is non-trivial insulator in two of them whereas one of the regions is related to the topologically trivial insulator. We find that the topologically trivial phase in the presence of both uniform spin-orbit coupling and uniform Zeeman magnetic field changes to a topologically non-trivial phase. The number of symmetry protected zero-energy edge states under open boundary conditions are also calculated, which suggest that the topological number reduces to the when applying Zeeman field. Furthermore, the symmetries of the Hamiltonian are investigated, implying that the system has time-reversal, particle-hole, chiral and inversion symmetries and belongs to the BDI class either in the presence or absence of uniform Zeeman magnetic field.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
717
727
http://ijpr.iut.ac.ir/article_1315_a528a4d356aac1f9aa1f7d1726c4d6fe.pdf
dx.doi.org/10.29252/ijpr.17.5.717
New black hole solutions of Gauss-Bonnet gravity in the presence of a perfect fluid
N
Farhangkhah
دانشگاه آزاد اسلامی واحد شیراز
author
text
article
2019
per
In this paper, the solutions of the Gauss-Bonnet theory of gravity was proposed in the presence of a perfect fluid with thermodynamic pressure P and energy gravity ρ in n-dimension. Accordingly, perfect fluid tensor was regarded as energy-momentum tensor and the static and radiating solutions for the linear equation of state p = wρ was calculated. This solution contains all the solutions already being proposed for Gauss-Bonnet gravity, such as asymptotically flat or asymptotically uncharged (anti)-de Sitter, radiating asymptotically flat and (anti)-de Sitter solutions as well as some new static and radiating solutions for different w values. We go through the properties of the new static and radiating solutions. We find solutions for w = 0 and w = (n-2)-2 in static and radiating states. We also show that the solutions satisfy the dominant and weak energy conditions and they present black holes with one or two horizons or naked singularities provided that the parameters of the solutions are chosen suitable.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
729
735
http://ijpr.iut.ac.ir/article_1316_e831abb0fdfb2fb930a417665f3f87bc.pdf
dx.doi.org/10.29252/ijpr.17.5.729
The influence of rotating wind in supercritical accretion disk with radiation pressure
F Z
Zeratgari
فردوسی مشهد
author
E
Delkhani
فردوسی مشهد
author
Sh
Abbassi
فردوسی مشهد
author
text
article
2019
per
We solved one-dimensional hydrodynamic (HD) equations of the slim disks in the presence of the wind and in cylindrical coordinates using self-similar solution. We considered power-law function of for mass loss rate due to wind. Then, we considered mass loss, angular-momentum loss and energy loss in equations. Then, we treated the influence of wind on the dynamics of the system. As an agreement with previous works, it was found that in the case of the slim disks, the effective temperature profile of slim disks is flatter with respect to that of the thin standard disks. Moreover, the mass and the angular momentum loss of the wind will increase the effective temperature of the slim disks. The results turned out that beside effective temperature of disks, the continuum spectrum emitted from the disk can also be affected in the presence of the wind
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
737
742
http://ijpr.iut.ac.ir/article_1317_89975472e02226881ddd8bb8310229f2.pdf
dx.doi.org/10.29252/ijpr.17.5.737
Analytical calculation of spin tunneling effect in single molecule magnet Fe8 with considering quadrupole excitation
Y
Yousefi
دانشکده فیزیک، دانشگاه پیام نور، تهران
author
H
Fakhari
دانشکده فیزیک، دانشگاه پیام نور، تهران
author
K
Muminov
انستیتوی فیزیک- تکنیکی اس. او. عمراف، آکادمی علوم، تاجیکستان
author
M R
Benam
دانشکده فیزیک، دانشگاه پیام نور، تهران
author
text
article
2019
per
Spin tunneling effect in Single Molecule Magnet Fe8 is studied by instanton calculation technique using SU(3) generalized spin coherent state in real parameter as a trial function. For this SMM, tunnel splitting arises due to the presence of a Berry like phase in action, which causes interference between tunneling trajectories (instantons). For this SMM, it is established that the use of quadrupole excitation (g dependence) changes not only the location of the quenching points, but also the number of these points. Also, these quenching points are the steps in hysteresis loops of this SMM. If dipole and quadrupole excitations in classical energy considered, the number of these steps equals to the number that obtained from experimental data.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
743
751
http://ijpr.iut.ac.ir/article_1318_02ded82df36299d0d5dc5a36415e12f9.pdf
dx.doi.org/10.29252/ijpr.17.5.743
Optimizing Carbonaceous Nanostructure Composition as a Substrate to Grow Co Electrocatalysts
M
Pourreza
دانشگاه صنعتی شریف
author
N
Naseri
دانشگاه صنعتی شریف
author
Sh
Ghasemi
دانشگاه صنعتی شریف
author
text
article
2019
per
Global warming and other adverse environmental effects of fossil fuels have forced humans to consider clean and renewable energy resources. In this context, hydrogen production from water splitting reaction is a key approach. In order to reduce required overpotential for water oxidation reaction, it is necessary to use low cost and earth abundant electrocatalysts like Co, Cu, Fe, Mn, Ni and Zn nanostructures. Herein, cobalt nanostructures on steel-mesh substrate were applied. Electrochemical method was used for growth of Co nanoflakes because of its simplicity and scalability for commercial approach. On the other hand, using carbonaceous support layers including nanomaterials such as graphene and carbon nanotubes, can reduce overpotential and increase efficiency of the electrocatalyst. According to the results, 40 wt% of graphene oxide and 60 wt% of carbon nanotubes in prepared carbon paste led to better growth for cobalt oxide nanoflakes. For the mentioned layer, cobalt was detected in metallic crystalline phase and the overpotential and electrical resistance measured 305 mV and 20 Ω, respectively.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
753
760
http://ijpr.iut.ac.ir/article_1319_4d0479761494052a52e3b9e765c989f9.pdf
dx.doi.org/10.29252/ijpr.17.5.753
Study of Shock Ignition Approach in Heavy Ion Fusion of Reactor-size DT Target
s
hasani
دانشگاه دامغان
author
B
kaleji
دانشگاه دامغان
author
soheil
khoshbinfar
دانشگاه گیلان
author
text
article
2019
per
The ignition of pre-compressed fuel by convergent shock wave, as a new approach in inertial confinement fusion that is known as shock ignition is considered with the aim of achieving high gain and providing threshold of ignition in lower energy. In this research, optimization of the energy of individual ions in the beam according to the hydrodynamic efficiency and target energy gain in a five-layer fuel pellet of nuclear fusion reactor size with heavy ion beam by one-dimensional code, DEIRA4. Then with substitution of the box pulse by three-stage pulse in shock ignition, the power and time of each phase are optimized and the energy consumption, fuel hydrodynamic efficiency and Rayleigh–Taylor instability is investigated. Calculations show that in optimal target with DT fuel, by applying three-stage pulse by heavy ion beam 207Pb, target energy gain is 542 corresponding to 21% increasing in energy efficiency and 19% decreasing in deriver energy. Also the decreasing of implosion velocity and e-fold parameter shows, the hydrodynamic instabilities in shock ignition is less than central ignition.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
761
772
http://ijpr.iut.ac.ir/article_1320_d3b5ae4d337b49cdb641c243f5bf78f9.pdf
dx.doi.org/10.29252/ijpr.17.5.761
The effects of Isoniazid drug adsorption on the structural and electrical properties of pristine and Ni doped (6, 0) zigzag gallium nitride nanotube: By DFT method
M
Rezaei Sameti
دانشگاه ملایر
author
F
Moradi
دانشگاه ملایر
author
text
article
2019
per
The aims of this project are to investigate the effects of Isoniazid drug adsorption on the geometrical and electrical structure of pristine and Ni-doped Gallium nitride nanotube (GaNNTs). For this purpose, 24 different configuration models are considered for adsorbing Isoniazid on the surface of nanotube and then all considered structures are optimized by using density function theory (DFT) at the Cam-B3LYP/6-31G (d) level of theory. By using optimized structures ,the structural parameters involve bond length and bond angle, HOMO and LUMO orbital, Density of state (DOS) plots, Quantum parameters, Natural bonding orbital (NBO), Atom in molecule (AIM), and Molecular electrostatic potential (MEP) are calculated by above level of theory and all results are analyzed. The results reveal that doping Ni atom and adsorbing Isoniazid molecule decrease the energy gap and global hardness of nanotube and thereby the electrical properties of system increase, this property is suitable to making nano sensors. At all adsorption models the values of adsorption energy is negative and show that the adsorption process is exothermic and stable in thermodynamic approach. On the other hand, the adsorption of Isoniazid on the surface of nanotube is physical adsorption. Comparison the thermodynamic properties demonstrate that the Ni-doped decrease the Isoniazid adsorption on the surface of nanotube therefor the adsorption of Isoniazid on the surface of the Ni-doped models is not favorable than pristine models. In addition, the adsorption of Isoniazid on the surface of nanotube is physical adsorption.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
773
794
http://ijpr.iut.ac.ir/article_1321_719db340403d9632c463411b049d055c.pdf
dx.doi.org/10.29252/ijpr.17.5.773
Optimization of a high-power coaxial coupler to 1800 waveguide coupler with high input power using CST simulator controlled by MATLAB
M
Mostajeran
دانشگاه دانشکده فیزیک، دانشگاه یزد، یزد
author
F
Kazemi
دانشکده فیزیک، دانشگاه یزد، یزد
author
text
article
2019
per
Coaxial couplers with high input RF power, usually operated at 500 MHz, are one of the critical components used in accelerators. To withstand high RF power, the couplers should be tested first, under identical conditions in a test stand. A waveguide coupled to a coaxial cable is used for this purpose. The parameter that indicates the amount of returned power loss is S11. By optimizing the dimensions of the proposed model this parameter can be reduced. MATLAB program has special and powerful tools to optimize the models which are simulated in CST STUDIO SUITE. In this paper the details of how MATLAB can control CST is described. Using MATLAB to control CST, the optimization of the coaxial coupler coupling 1800 waveguide is carried out.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
795
804
http://ijpr.iut.ac.ir/article_1322_abcacaf7eaab244a72776bf4025ce7b2.pdf
dx.doi.org/10.29252/ijpr.17.5.795
Quantum efficiency of Core/ Shell GaN/AlGaN quantum dot photodetector
Ali
Vahedi
دانشگاه ازاد اسلامی
author
text
article
2019
per
In this work, oscillator strength and quantum efficiency of new spherical GaN/AlGaN quantum dot was investigated. In order to obtain these parameters, at first, Schrödinger equation is solved in GaN/AlGaN spherical coordinate system in effective mass approximation, and energy level, wave function and transition matrix element of the parameter are obtained. The results show that oscillator strength decreases with increase of mol fraction and dot size. This effect is more obvious for high mol fractions. With increasing mol fraction of defect, the peak of quantum efficiency shows blue shift. Increasing the radius of core and shell causes the red shift of quantum efficiency peak. The red and blue shifts can be very useful in tunning and controling the detector wavelenght range
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
805
812
http://ijpr.iut.ac.ir/article_1323_315da506d7fc5ad0402133df0d5c4260.pdf
dx.doi.org/10.29252/ijpr.17.5.805
Effective field theory of anisotropic inflation in Weinberg's approach
T
Rostami
پژوهشکده نجوم، پژوهشگاه دانشهای بنیادی
author
H
Firouzjahi
پژوهشکده نجوم، پژوهشگاه دانشهای بنیادی
author
A
Karami
پژوهشکده نجوم، پژوهشگاه دانشهای بنیادی
author
text
article
2019
per
In this paper, the effective field theory for the anisotropic inflationary universe in Weinberg's approach is studied. We consider the leading correction terms to the standard interactions in the anisotropic inflationary models. These consist of forth derivative of the fields, scalar field, gauge field and metric. Then, the scalar power spectrum is investigated in the presence of higher energy interactions, and the corrections of power spectrum are calculated.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
813
818
http://ijpr.iut.ac.ir/article_1324_dbf932a1321fc6069d3dc8089e1dac2c.pdf
dx.doi.org/10.29252/ijpr.17.5.813
Profile of temperature in the dissipative over-dense plasma
L
rajaei
دانشگاه قم، قم
author
N
arefiyan
دانشگاه قم، قم
author
text
article
2019
per
In this paper, an investigation is undertaken to introduce a simple and effective mechanism of over-dense plasma. The collisional effects reduce the rate of the energy transmission. In the collisional dissipative plasma, dielectric coefficient is complex due to collision and the imaginary part of dielectric coefficient is related to the collision. Materials with complex dielectric coefficient, such as ceramics can be heated easily by microwaves. Here, it is shown that it is possible to heat over-dense plasma in which light transmission is done through excited surface plasma. Also, the temperature increase is due to energy dissipation caused by collision.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
17
v.
5
no.
2019
819
823
http://ijpr.iut.ac.ir/article_1325_80a715b091e4f45f4a57def22272104e.pdf
dx.doi.org/10.29252/ijpr.17.5.819