Study of neutron-rich nuclei reaction using ImQMD model
V
Zanganeh
Department of Physics, Golestan University, Gorgan, Iran
author
A
Izadpanah
Department of Physics, Golestan University, Gorgan, Iran
author
M
Ahmadi
Department of Physics, Golestan University, Gorgan, Iran
author
text
article
2021
per
In the present study, the fusion reactions induced by neutron-rich nuclei have been investigated using the improved quantum molecular-dynamics (ImQMD) model. First, the accuracy of the results was determined by using a set of parameters IQ3a for 16O+92Zr, 40Ca+46Ti and 16O+154Sm fusion excitation functions. The obtained results revealed that the measured fusion excitation function can be reasonably well reproduced. A comparison was also performed with the theoretical results based on the coupled-channel calculations. Then, the time evolution of densities for the 16O+59Co and 32S+92Zr reactions in which the target nuclei were neutron-rich were studied and the fusion cross sections were calculated dynamically. It was found that the fusion cross sections of these reactions at energies around the Coulomb barrier can be well reproduced by using the ImQMD modle.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
569
577
https://ijpr.iut.ac.ir/article_1649_f89ae25db38171f516e5c1e3229b6f50.pdf
dx.doi.org/10.47176/ijpr.20.4.27311
Study of the optical properties of Aluminum zigzag thin films
via transfer matrix
M
Gholizadeh Arashti
Department of Physics, Faculty of science,Yadegar-e-Imam Khomeini (RAH) Shahre Rey Branch, Islamic Azad University, Tehran, Iran
author
M
Fakharpour
Department of Physics, Faculty of science, Maybod Branch, Islamic Azad University, Maybod, Iran
author
text
article
2021
per
The transfer matrix method adopted to solve the linearly polarized light propagation problem in order to study the occurrence of absorption transitions for Aluminum zigzag thin films. For different incident light, azimuthal angles, arms number and lengths, the optical results showed that the intensity of absorption peak of s-polarization remains constant as the incident light angle increases, while the intensity of absorption peaks for p-polarization increases. According to the variations of spectra for different azimuthal angles, the results of p-polarization are opposite to s polarization. Also, changing the number of arms from two to three, three to four and four to five, shift the peaks of absorption spectrum towards longer (red shift), shorter (blue shift) and longer wavelengths (red shift), respectively. This behavior can be observed for zigzag nano-structure with different arm lengths.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
579
589
https://ijpr.iut.ac.ir/article_1650_0bd9db4386564777c3c0cd70da3eaf31.pdf
dx.doi.org/10.47176/ijpr.20.4.5121
Visible and near infrared upconversion emission from Tm3+, Yb3+ doped SrF2 nanoparticles
M
Ghorashi
Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran, Iran
author
H R
Madaah-Hosseini
Department of Materials Science and Engineering, Sharif University of Technology, Tehran, Iran
author
E
Mohajerani
Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran
author
text
article
2021
per
Tm3+, Yb3+-codoped SrF2 nanoparticles were synthesized through a facile hydrothermal technique. Citrate ions were introduced as the capping agent into the reaction. Upconversion nanoparticles were characterized by field emission scanning electron microscopy (FESEM), Energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD), Dynamic light scattering (DLS), Zeta potential, Fourier transform Infrared spectroscopy (Ft-IR), and the 980 nm laser induced photoluminescence spectroscopy. Rare-earth ions (Na+), which are the cations of citrate salts, are incorporated into the structure to act as charge compensators. Upconversion emission in the visible and NIR region was observed by the 980 nm irradiation. Nanoparticles with a narrow size distribution and a uniform morphology were directly dispersible in water, forming a quite transparent suspension. Nanoparticles size was approximately 10 nm. High penetration of the Near-Infrared light into the body tissue makes these nanoparticles appropriate for tumor targeting in the deeper tissues for the purpose of bioimaging and photodynamic therapy.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
591
597
https://ijpr.iut.ac.ir/article_1651_da7e2fa105954ae9fe6032da9eeba155.pdf
dx.doi.org/10.47176/ijpr.20.4.37861
Assessment of the absorbed dose uncertainty of prostate due to tissue swelling and radioactive sources displacement in brachytherapy using
Monte Carlo method
Z
Aghaei
Physics Department , Isfahan University of Technology, Isfahan, Iran
author
Alireza
Karimian
Department of Biomedical Engineering, Faculty of Engineering, University of Isfahan
author
M H
Alamatsaz
Physics Department , Isfahan University of Technology, Isfahan, Iran
author
text
article
2021
per
Brachytherapy is a kind of cancer treatment in which radiation sources are implanted inside or close to the cancerous tissue. The purpose of this research is to calculate the absorbed dose uncertainty of prostate tissue, due to its swelling, displacement of the implanted seed sources and also, to address the effect of these factors simultaneously, in brachytherapy of prostate. In this research, MCNPX2.6 code, the TG-43U1 protocol and ORNL body phantom were used to simulate the brachytherapy of prostate using iodine-125 seed sources. In the first study, 84 sources of iodine with the shapes of seed and then points were implanted inside the prostate with the volume of 38.01 cm3. The radiation absorbed dose was found to be 110.59 and 110.57 Gy, respectively. Considering the 50% prostate inflation after implantation, the radiation absorbed doses of prostate showed a reduction of more than of 17%. In the second therapeutic plan, by using 76 seed sources of I-125, considering 12% swelling of prostate and applying the displacement of seed sources in three directions: left–right (1.8mm), front-back (2.1mm) and top–down (3.4mm)), the radiation dose amount of the cancerous tissue was reduced about 21%. So, the results of seed and point sources of brachytherapy were very close to each other. Therefore, in simulation studies, point sources can be used instead of seed sources to reduce the computational complexity. Also, this research showed the effects of swelling and displacement of brachytherapy sources on the amount of the absorbed dose of prostate and its treatment were noteworthy.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
599
613
https://ijpr.iut.ac.ir/article_1652_dfeb7fc032bcb76a1f87cb172b0984fa.pdf
dx.doi.org/10.47176/ijpr.20.4.41043
Investigation of factors affecting on the efficiency of second harmonic generation of the continuous-wave focused Gaussian beam of 1064 nm inside the periodically poled nonlinear crystals
H
Amrollahi
Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran
author
A
Arabanian
Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran
author
text
article
2021
per
In this research, the nonlinear propagation equations of the fundamental and second harmonic waves coupled to the heat equation are solved for a focused Guassian beam inside two quasi-phase matched periodically poled MgO: PPLN and MgO: PPLT crystals, and the optimum focal length and radius of the continuous-wave laser beam with the wavelength of 1064 nm and with Gaussian profile, and also, the optimal phase-mismached parameter are calculated and the dependence of the second harmonic efficiency on these parameters is shown. Also, the effects of the thermal distribution inside the crystal on the second harmonic generation efficiency are investigated and it is shown how the thermal distribution reduces the second harmonic efficiency and, accordingly, the optimal crystal length for different incident powers is determined and shown that the lower crystal lengths should be selected for higher incident powers. Finally, a comparison between the second harmonic efficiencies in two crystals of MgO: PPLN and MgO: PPLT is performed considering the thermal distribution for different insident powers and it is shown that for the lower/ higher incident power than 21 watts, the crystal of MgO: PPLN / MgO: PPLT is more suitable and more efficient for second harmonic generation.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
615
625
https://ijpr.iut.ac.ir/article_1653_2d10cee4b7ba5b6ac1a32dbc51826250.pdf
dx.doi.org/10.47176/ijpr.20.4.37381
Nonlinear coupling of two nonlinear coupled plasmonic nanowires in the presence of Kerr and two-photon absorption in the modes of TM00 and TM10
A
Ghadi
Atomic and Molecular Physics Group, Faculty of Basic Sciences, University of Mazandaran, Iran
author
F
Habibi
Atomic and Molecular Physics Group, Faculty of Basic Sciences, University of Mazandaran, Iran
author
S
Mirzanejhad
Atomic and Molecular Physics Group, Faculty of Basic Sciences, University of Mazandaran, Iran
author
text
article
2021
per
The nonlinear interactions of coupled nanowires are important phenomena in data processing of integrated photonic circuits. In this paper, we investigate the nonlinear coupling of two silver nonlinear coupled plasmonic nanowires for TM00 and TM10 modes under different amplitudes in the presence of Kerr effect, and the other case that the medium has Kerr and two photon absorption (TPA) effect too. The results show that in the presence of TPA effect the nonlinear optical effects appear in lower input amplitudes than Kerr effect. The Kerr effect occurs in upper intensities than the TPA effect and nonlinear optical effect leads to decrease the exchange of plasmonic waves between two nanowires. Also, the coupling length (Lc), that it means the characteristic length of the structure has a lower coupling distance that through propagating in the medium the transfer of the wave is completely, in TM00 mode is lower than TM10 mode. Also, the results show that for different values of initial amplitudes of field in a fixed value of Lc, the coupling efficiency increases with increasing the value of intensity.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
627
635
https://ijpr.iut.ac.ir/article_1654_f57a749d088e43733f58707841973859.pdf
dx.doi.org/10.47176/ijpr.20.4.71084
Effective quadruple deformation of (128-160)Nd isotopic chain
A
Hosseinnezhad
Department of Physics, University of Tabriz, Tabriz, Iran
author
A
Jalili Majarashin
Department of Physics, Liaoning Normal University, Dalian, China
author
H
Sabri
Department of Physics, University of Tabriz, Tabriz, Iran
author
P
Feng
Department of Physics, Liaoning Normal University, Dalian, China
author
text
article
2021
per
The aim of this paper is to calculate the effective quadruple deformation of different levels in the Nd isotopic chain in the framework of the boson interaction model. For this purpose, by labeling the selected states in the form of the dynamic limit of U(5), the expectation value of the quadruple interaction operator is calculated and the quadruple shape invariant and the Effective quadruple deformation of levels are obtained and compared to the corresponding experimental values, the effective boson charge for each isotope has been determined. The results show the existence of overlap in the values of the effective quadruple deformation of 0_3^+ and 2_1^+ levels in this isotopic chain. Also, a certain relationship is observed between the effective quadruple deformation values and the effective Boson charge and the spacing of the levels. The existence of this dependence for the Nd isotopic chain and the overlap of quantities can be reported as signs of shape coexistence in (_60^140)Nd and (_60^142)Nd and (_60^146)Nd isotopes.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
637
647
https://ijpr.iut.ac.ir/article_1655_d3096258adcd6ca6cce3e8b32e225a01.pdf
dx.doi.org/10.47176/ijpr.20.4.51061
New Methode for Synthesis of PbO Nano-Rods and its application in ionizing radiation shielding
S
Yazdani Darki
Nuclear Physics Division, Physics Department, University of Yazd, Yazd, Iran
author
M
Eslami-Kalantari
Nuclear Physics Division, Physics Department, University of Yazd, Yazd, Iran
author
H
Zare
Solid State Physics Division, Physics Department, University of Yazd, Yazd, Iran
author
text
article
2021
per
We successfully synthesized PbO nanorods by a simple and low-cost approach using Pb(CH3COO)2.3H2O, NaOH as the starting materials without any surfactants in water media at room temperature. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–Vis), and photoluminescence spectrophotometer (PL) were used to characterize the samples. The prepared nanorods had the average diameter of about 40 nm, the average length of about 6 µm and the average crystallite size of about 57 nm. PbO nanorods showed good gamma and beta attenuation; so, they could be considered as a potential candidate for radiation shielding.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
649
655
https://ijpr.iut.ac.ir/article_1656_aa1a52e433a3f8655d533111434dca45.pdf
dx.doi.org/10.47176/ijpr.20.4.38211
Investigation of Laser wakefield acceleration using relativistic
Vlasov-Maxwell code
M
Ghorbanalilu
Department of Physics, University of Shahid Beheshti, Tehran, Iran
author
S.N
Razavinia
Department of Physics, University of Shahid Beheshti, Tehran, Iran
author
text
article
2021
per
In this paper we investigate the electron laser wakefield acceleration using numerical solution of relativistic Vlasov-Maxwell equations with Semi-Lagrangian method. We found optimum pulse length to excite strong wakefields by investigation of electric fields and density variation, which caused by propagation of intense relativistic laser pulse through underdense plasma as well as average kinetic energy of electrons, for lasers with different pulse lengths.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
657
665
https://ijpr.iut.ac.ir/article_1657_a00e8073c2020d617e094628c2c3a15d.pdf
dx.doi.org/10.47176/ijpr.20.4.31754
Application of the residual surface delta interaction in the /beta+ decay of (_^"40" )"Sc" nucleus
A
Yarahmadi
Department of Physics, Faculty of Science, University of Sistan and Baluchestan, Zahedan, Iran
author
V
Dehghani
Department of Physics, Faculty of Science, University of Sistan and Baluchestan, Zahedan, Iran
author
S A
Alavi
Department of Physics, Faculty of Science, University of Sistan and Baluchestan, Zahedan, Iran
author
text
article
2021
per
In this paper the beta decay of Sc40 has been investigated. Using the eigenfunctions of the spherical oscillator the eigenvalues and eigenfunctions of the Woods-Saxon potential with spin-orbit and Coulomb terms have been calculated. In order to obtain the more realistic nuclear wave functions, the surface delta interaction potential has been used as the residual interaction between the valence nucleons in the frame work of Tamm-Dancoff approximation (TDA) in the case of Ca40 and particle-hole Tamm-Dancoff approximation (pnTDA) in the case of Sc40 . The potential constants have been obtained by fitting the results with the experimental data. The half-life and transition probability of positive beta decay of Sc40 have been calculated. Good greement with the experimental data was observed.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
667
679
https://ijpr.iut.ac.ir/article_1658_05849fd2ba5eff25d4d02c2e61cb1aff.pdf
dx.doi.org/10.47176/ijpr.20.4.19642
Generation of new modes in the process of passing waves through two semi-bounded waveguides with cylindrical metallic wall , with a dissipative plasma rod in one of them
S
Najari
Faculty of Physics, Department of Photonics and Plasma, University of Kashan, Kashan, Iran
author
B
Jazi
Faculty of Physics, Department of Photonics and Plasma, University of Kashan, Kashan, Iran
author
text
article
2021
per
In this paper, the generation of the new modes in the problem of the transfer of the electromagnetic waves from a semi-bounded cylindrical waveguide with a metallic wall to a plasma column are investigated. An electromagnetic wave with the symmetric mode TM0j is send from a semi-bounded cylindrical dielectric waveguide to a plasma column. The plasma column is placed on the axis of another semi-bounded dielectric waveguide. Two mentioned waveguides are connected to each other in z=0. The incident wave is reflected and transmitted on the interface surface of two waveguides. The reflected and transmitted waves are considered as a series of the new modes and by using appropriate boundary conditions, the reflection and transmission coefficients of each new mode are calculated. The calculations are shown that the reflection and transmission coefficients of the reflected and transmitted waves are a function of the collision frequency of the plasma. Also, the phase different of the reflected and transmitted waves respect to the incident are shown because the reflection and transmission coefficients are obtained as a complex number. The graphs of the transmission and reflection coefficients and the graphs of the phase difference of the reflected and transmitted waves in terms of the collision frequency of the plasma are investigated.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
681
691
https://ijpr.iut.ac.ir/article_1659_82e378b9c87c167fdae3a4fa605814ed.pdf
dx.doi.org/10.47176/ijpr.20.4.15883
Study of spinning particles around rotating black holes
J
Khodagholizadeh
Department of Physics, Farhangian University, Tehran, Iran
author
A
Vahedi
Department of Physics, Kharazmi university, Tehran, Iran
author
text
article
2021
per
The orbital velocity profile around the Kerr black holes has a non-monotonic radial behavior in the Locally Nonrotating Frames (LNRF). Using Mathisson- Papapetrou- Dixon equation for a massive spinning particle, again this maximum-minimum feature has been shown by considering the linear spin approximation. Also the spin of black holes and absolute value of particle's spin have an important rule in Aschenbach effect.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
693
698
https://ijpr.iut.ac.ir/article_1660_6038f839b5fc443daba6412a0d4ff5c2.pdf
dx.doi.org/10.47176/ijpr.20.4.37971
Comparison of polarization sensitive second harmonic generation microscopy techniques for the study of biological tissues
M
Alizadeh
Department of Physics, University of Kurdistan, Sanandaj, Iran
author
M
Ghotbi
Department of Physics, University of Kurdistan, Sanandaj, Iran
author
text
article
2021
per
Recently, polarization sensitive Second Harmonic Generation (pSHG) microscopy has become a powerful tool for the study of the noncenterosymmetric biological structures. This is due to the fact that pSHG has some intrinsically benefits such as high resolution and contrast, and it can also penetrate deeply inside the sample in a noninvasive manner. One drawback for the pSHG technique is that the imaging procedure is not fast enough to study in vivo samples or to monitor the dynamics of different tissues. This issue imposes some limitations on using the pSHG technique to study in vivo samples. Fortunately, recently Single Scan polarization sensitive Second Harmonic Generation (SS-pSHG) technique has been introduced as a fast alternative for the conventional pSHG technique. In this article, the results obtained from ex vivo biological samples of starch, human cornea and animal tendon have been compared in a pixel-to-pixel manner using pSHG and SS-pSHG techniques in forward direction. Even though the samples used here are ex vivo, the results of this study promise that the polarization sensitive SHG microscopy techniques have a great potential to study biological tissues in a noninvasive procedure. This issue is more important especially in the cases that samples are in vivo.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
699
709
https://ijpr.iut.ac.ir/article_1661_329f2743a8d28433186f5c31aa915ca1.pdf
dx.doi.org/10.47176/ijpr.20.4.61079
Simulation of possibility of detecting gamma rays emitted from
crab by Alborz-I array
Y
Pezeshkian
1. Department of Physics, Sahand University of Technology, Tabriz, Iran
2. Alborz Observatory, Sharif University of Technology, Tehran, Iran
author
A
Laletaheri
Department of Physics, University of Zanjan, Zanjan, Iran
author
text
article
2021
per
Crab Nebula, as an active source of high energy gamma-rays, is a common standard source used for calibrating different gamma-ray telescopes and observatories. Since gamma rays with energies above 100 TeV from crab is reported, it is possible to detect gamma rays emitted from this nebula by a suitable ground based detector array. Alborz-I array is designed to study cosmic rays with energies around the knee of cosmic ray spectrum. In this paper, it is shown that the current location and configuration of Alborz-I, makes it impossible to detect Crab gamma rays. Our simulation shows that the average rate of gamma particle detection reaches to something above 1 gamma particle in 2 years, which is very difficult to distinguish from cosmic ray background. Finally some proposals to constructing an array with capability of detecting Crab gamma rays are presented.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
711
716
https://ijpr.iut.ac.ir/article_1662_a2b6caa70b1591231db91c9af999a0df.pdf
dx.doi.org/10.47176/ijpr.20.4.71099
Investigation of multi-quark systems
F
Abdi
Physics department, Razi University, Kermanshah
author
G. R
Boroun
Physics department, Razi University, Kermanshah, Iran
author
text
article
2021
per
In this study, the researcher decided to study Tetraquark and Pentaquark systems. We introduce the Pentaquark system as a meson-baryon system and Tetraquark as a diquark-antidiquark system. A diquark consists of two quarks. The interaction potential between these particles is considered as a combination of two color charge potentials and the confinement potential is considered as harmonic and linear sentences. Solve the Schrodinger equation by considering the effects of spin-spin, isospin- isospin, spin-isospin, and then obtain the mass of the diquark and the heavy tetraquuarks with charm quarks and bottom. These calculations are calculated using the approach of diquark - antidiquark within the framework of the non-relativistic quark model. In the following, we calculate the mass of Pentaquark systems in the same way.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
717
725
https://ijpr.iut.ac.ir/article_1663_c9185a63b0e4c3d0782093341ad54af3.pdf
dx.doi.org/10.47176/ijpr.20.4.41048
Warm intermediate and logamediate cosmic inflation with a constant dissipation coefficient in loop quantum gravity
A
Ravanpak
Department of Physics, Faculty of Science, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
author
M R
Setare
Department of Science, Campus of Bijar, University of Kurdistan, Bijar, Iran
author
text
article
2021
per
Warm inflationary model in the context of loop quantum cosmology is investigated. To this aim we consider two cases intermediate inflation and logamediate inflation. In both the cases, assuming a constant dissipation coefficient, we study the model under consideration in weak dissipation regime and also in strong dissipation regime. In each of these cases, we obtain various parameters such as potential function of inflationary scalar field and slow-roll parameters. Perturbation theory and also finding relations between perturbative parameters is studied.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
727
735
https://ijpr.iut.ac.ir/article_1664_3f68eee38e4966a7b7555f8d2e971406.pdf
dx.doi.org/10.47176/ijpr.20.4.37311
Thin accretion disks around multi-polytropic wormhole
M
heydari-Fard
Department of Physics, The University of Qom, Qom, Iran
author
F
Eghbalpoor
Department of Physics, The University of Qom, Qom, Iran
author
text
article
2021
per
In this paper, we study the physical properties of thin accretion disks in static and spherically symmetric multi-polytropic wormhole space-time. Using the Novikov-Thorne model, the electromagnetic flux, temperature distribution, innermost stable circular orbits and radiative efficiency of thin disks are obtained. Comparing the results with traversable wormholes obtained by Morris and Thorne (TWH) and the Schwarzschild solution, we show that thin accretion disks around multi-polytropic wormhole geometry are more luminous and more efficient than the TWH and Schwarzschild black hole.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
737
746
https://ijpr.iut.ac.ir/article_1665_4b623a26b550e9a1ec6c998dc799212f.pdf
dx.doi.org/10.47176/ijpr.20.4.71085
Conceptual design, manufacturing and investigation of dipole plasma antenna with the capability of frequency variation in the VHF band
M
Amiri
Department of Physics, University of Mohaghegh Ardabili, Ardabil, Iran
author
N
Sepehri Javan
Department of Physics, University of Mohaghegh Ardabili, Ardabil, Iran
author
text
article
2021
per
In this article, we simulate and manufacture a dipole plasma antenna whose frequency is variable in the VHF band. The conductive medium of antenna is the plasma created by the DC discharge in a glass tube. To excite the antenna, we use a cylindrical aluminum coupler installed at the middle of the antenna. By varying values of gas pressure, input impedance of circuit and the voltage deference between two ends of the plasma medium, one can change the working area of antenna at a few hundred gigahertz frequency interval. Simulation and numerical calculations are carried out for an antenna with 78cm length and 2cm radius at 0.8 bar pressure exerted under 15KV voltage difference. At constant pressure, by using some parallel resistors in the antenna circuit, the impedance of discharge circuit is changed and consequently the plasma density is varied. For plasma frequencies and , using semi-experimental formulae, analysis shows resonances at frequencies 250MHz and 311MHz, respectively, which are in good agreement with the experimental results which take place at frequencies 217MHz and 272MHz. Additionally, simulation is accomplished for a metal antenna with corresponding geometry whose working frequency detected at 184MHz.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
747
758
https://ijpr.iut.ac.ir/article_1666_a246f18b40ab255d0f5c337fa7b2bd6d.pdf
dx.doi.org/10.47176/ijpr.20.4.27821
Comparison of mechanical, optical and electronic transport properties of isotropic and anisotropic borophosphene
M
Pashangpour
Department of Physics, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran
author
text
article
2021
per
In this research, mechanical, optical and electronic transport properties of two phases of graphene-like borophosphene are investigated using density functional theory. Graphene-like borophosphene, a honeycomb structure with equal ratio of boron and phosphorus atoms, is introduced in two isotropic and anisotropic phases. For this purpose, band structure, partial density of states, Young’s modulus, Poisson ratios, dielectric function, and current-voltage characteristics are calculated and compared. The results show that the anisotropic phase of graphene-like borophosphene is semimetal and the isotropic phase is a semiconductor with a direct energy gap of 0.9 eV. Moreover, the Young’s modulus has the highest values for both phases in the zigzag and armchair directions of crystal, and the Poisson ratio has the lowest values in these two directions. Besides, optical properties of these two structures include electron energy loss spectroscopy, refractive index, extinction coefficient, optical conductivity and reflection coefficient for parallel and perpendicular polarization of electric fields respect to the sheets are computed by real and imaginary parts of dielectric function using random phase approximation. Plasmon’s energies are obtained 2.24 and 8.88 eV in the armchair direction and 9.01 eV in the zigzag direction for the anisotropic phase and for the isotropic phase, 3.38 and 9.12 eV are obtained in both directions. Both phases are transparent respect to visible light polarized in the perpendicular direction to the crystal, and the reflection and absorption are zero. Due to the selective transmission / absorption / reflection of the electromagnetic wave in the crystals, this material is suggested as a suitable candidate in the fabrication of nano optoelectronic devices. Furthermore, Ohmic behavior is observed in current-voltage characteristics of the isotropic phase after the threshold bias voltage of 0.9 V. As a result of the high Fermi velocity of charge carriers in the anisotropic phase of borophosphene ( ), this material can be used in nanoelectronic devices.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
759
771
https://ijpr.iut.ac.ir/article_1667_ab7ae9eefe3d2c8dbbbd88e675a1acbf.pdf
dx.doi.org/10.47176/ijpr.20.4.11149
Relativistic electron dynamics in ion channel guiding in the presence of a helical wiggler and an external oblique magnetic field
A
Kargarian
Plasma and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute, Tehran, Iran
author
text
article
2021
per
In this paper, the electron acceleration and its relativistic dynamics in an ion-channel formed due to the laser pulse propagation through the plasma and under influence of the ion channel space-charge and a heliacal wiggler as well as the oblique magnetic field have been investigated. The equations for investigation of the electron dynamics are the tree-dimension Lorentz equations. For analytical analysis of the obtained equations, a three-dimension single particle code and forth order Runge-Kutta method is used as well. The electron energy gain and the relativistic electron dynamics drastically are affected by the ion-channel potential and the helical wiggler and also the external oblique magnetic field. The results of this paper can be significant in the selection of the appropriate parameters for plasma-based accelerators design.
Iranian Journal of Physics Research
Isfahan University of Technology,
The Physics Society of Iran
1682-6957
20
v.
4
no.
2021
773
778
https://ijpr.iut.ac.ir/article_1668_111e1e8f98980d0cdc03d4899daa7375.pdf
dx.doi.org/10.47176/ijpr.20.4.1072