A study of evoloutionary self-gravitating plytropic Î² -viscous accretion disks with troidal magnetic field
J
Ghanbari
دانشگاه فردوسی مشهد
author
SH
Abbassi
دانشگاه علوم پایه دامغان
author
N
Jami al ahmadi
موسسه آموزش عالی خیام مشهد
author
text
article
2019
per
In this paper,the effect of troidal magnetic field is studied in standard self-gravitating thin disks with β priscription. By applying the magnetic field, we expect to see different behaviors compared to a non-magnetic field case.The study reveals self-similar solutions for radial infall velocity, rotation velocity, surface density and mass accretion rate. Our results also show that by increasing the magnetic field, the radial velocity and mass accretion rate, at least in the inner regions of the disk,become slow and low, respectively. By contrast, in the outer regions, the azimuthal velocity and surface density become fast and high, respectively.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
11
v.
1
no.
2019
1
6
http://ijpr.iut.ac.ir/article_904_d27fe218eeb46b3edfe769df34acd0da.pdf
Design and simulation of an accelerating and focusing system
A
Sadeghipanah
دانشگاه شهید بهشتی تهران
author
F
Abbasi Davani
دانشگاه شهید بهشتی تهران
author
text
article
2019
per
Electrostatic focusing lenses have a vast field of applications in electrostatic accelerators and particularly in electron guns. In this paper, we first express a parametric mathematical analysis of an electrostatic accelerator and focusing system for an electron beam. Next, we At design a system of electron emission slit, accelerating electrodes and focusing lens for an electron beam emitted from a cathode with 4 mm radius and 2 mA current, in a distance less than 10 cm and up to the energy of 30 keV with the beam divergence less than 5°. This is achieved by solving the yielded equations in mathematical analysis using MATLAB. At the end, we simulate the behavior of above electron beam in the designed accelerating and focusing system using CST EM Studio. The results of simulation are in high agreement with required specifications of the electron beam, showing the accuracy of the used method in analysis and design of the accelerating and focusing system.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
11
v.
1
no.
2019
7
14
http://ijpr.iut.ac.ir/article_905_7e817ee560ed14a326ab891893251b0b.pdf
Thickness and roughness measurements of nano thin films by interference
A
Sabzalipour
دانشگاه تهران
author
MH
Mohammadizadeh
دانشگاه تهران
author
text
article
2019
per
In the standard optical interference fringes approach, by measuring shift of the interference fringes due to step edge of thin film on substrate, thickness of the layer has already been measured. In order to improve the measurement precision of this popular method, the interference fringes intensity curve was extracted and analyzed before and after the step preparation. By this method, one can measure a few nanometers films thickness. In addition, using the interference fringes intensity curve and its fluctuations, the roughness of surface is measured within a few nanometers accuracy. Comparison of our results with some direct methods of thickness and roughness measurements, i.e. using surface profilemeter and atomic force microscopy confirms the accuracy of the suggested improvements.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
11
v.
1
no.
2019
15
25
http://ijpr.iut.ac.ir/article_906_b5d84f3cb706c278e77ef604050c6cf5.pdf
Evaluation of the possible changes in diurnal temperature range (DTR) trend in some arid climates of Iran since last five decades
AA
Sabziparvar
دانشگاه بوعلیسینا همدان
author
R
Mirgaloybayat
دانشگاه بوعلیسینا همدان
author
F
Ghyami Shamami
دانشگاه بوعلیسینا همدان
author
text
article
2019
per
Climate is an important and determinning factor affecting many agricultural products. Diurnal temperature range (DTR) is an effective parameter in assessing climate change impacts on environment in a region. This parameter is determined by the difference between minimum and maximum air temperatures. In this study, changes in the daily DTR collected from 11 synoptic stations were analyzed. The selected sites cover 50 years of daily observations from 1956 to 2005, specifying suitable geographical distribution throughout the country. Kolmogrov-Smirnov test was used to check the normal distribution and Run-test to control the quality of the temperature data. Trend investigation of DTR data was carried out by using Mann-Kendall test (MK) and linear regression method (LR) at 95 percent confidence level for monthly and annual time scales. About 18 percent of the study sites showed no significant DTR trend, but the rest of the sites (82%) revealed significant negative (decreasing) trends for the observed diurnal temperature difference time series. However, few months experienced no DTR trend in the selected sites. In about 95.5 percent of the studies cases, the existence of trend and the decreasing DTR trends obtained by MK test were also confirmed by the LR method. In this research, the minimum and maximum slopes were determined by the LR method. The analysis of the measured temperature data showed an average decreasing in DTR slope about -0.445oC per decade for the selected sites. According to the results, the decreasing DTR trends in northern and central sites were more significant than those in the southern regions. Detailed evaluation and substantiation.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
11
v.
1
no.
2019
27
37
http://ijpr.iut.ac.ir/article_907_a56bd5cdb73cb17bbff0580fe6c5114e.pdf
A new thermoluminescence mixed order model for continuous and uniform distribution of trapping centers
M
Zahedifar
دانشگاه کاشان
author
S
Harooni
دانشگاه کاشان
author
text
article
2019
per
A mixed order model is proposed for describing thermoluminescence (TL) glow peaks with continuous and uniform distribution of trapping states. It is shown that the presented function reduces to the simple known models at the limiting cases. The function for TL intensity has been introduced in terms of intensity and temperature of the peak maximum. These parameters can easily be estimated from the shape of the glow peak as initial guesstimate for the curve fitting procedure. Considering the direct relation between the parameters entered in the proposed model and the physics of TL phenomenon, it is deduced that it is more appropriate for describing TL peaks with continuous distribution of trapping states.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
11
v.
1
no.
2019
39
46
http://ijpr.iut.ac.ir/article_908_ebf81423c8afa0c850382428da06139f.pdf
Acoustic waves loss in Al-7075-T6 and St 304
A
Abdullah
دانشگاه صنعتی امیرکبیر
author
M
Malaki
دانشگاه صنعتی امیرکبیر
author
text
article
2019
per
Propagation and dispersion of acoustic waves is one of the important phenomena in physics. Acoustic-waves are nowadays widely used in a variety of applications ranging from underwater communications, identification and specification of the internal defects of materials to extracorporeal shock wave lithotripsy. Apart from application and utilization of such phenomena, study on production and propagation of acoustic waves have a special importance. This paper is focused on the experimental and the analytical investigation of acoustic-waves loss in metallic materials. Firstly, the governing differential equations of the acoustic waves propagation are derived and solved for a damped cylindrically shaped rod. With regard to boundary and initial conditions, the equation and the curve of damped acoustic wave displacement are obtained. By using experimental modal techniques, experimental investigations on the energy loss and the extraction of damping coefficients of acoustic waves are done. The experimental information obtained from experimental tests such as Frequency Response Function, the formula and the curve of the energy loss versus frequency are extracted. Selected metallic materials for the experimental set-ups are two specimens of steel and aluminum.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
11
v.
1
no.
2019
47
54
http://ijpr.iut.ac.ir/article_909_7fd5e19cd1f67f7f548c9cb33f60ad1f.pdf
The usage of resonance optical absorption method for measurement of Cu atoms during the plasma sputtering deposition
H
Naghshara
دانشگاه تبریز
author
S
Sobhanian
دانشگاه تبریز
author
N
Sadeghi
دانشگاه گرونوبل فرانسه
author
text
article
2019
per
In this paper, the resonance optical absorption method, is used to measure the Cu atoms number density in different power levels of power supply. Atoms are sputtered from a Cu target during plasma magnetron sputtering deposition. For the light source, a commercial Cu hollow cathode lamp is used. For measurement of gas temperature, a small percentage of N2 is added to the gas mixture and the gas temperature is found by optical emission technique.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
11
v.
1
no.
2019
55
61
http://ijpr.iut.ac.ir/article_910_ffb84fb1aeb4d4145bb541e57e0c7e33.pdf
The effect of Hadron mass on the energy distribution function of Hadron
SM
Moosavi Nejad
دانشگاه یزد
author
AN
Khorramian
دانشگاه سمنان
author
text
article
2019
per
In the Hadronic interactions, the point which is less considered is the mass effect of interacting Hadrons on the energy distribution function of outgoing Hadrons. In this article we present a method to incorporate these mass effects which leads us to improve one of the basic formulas in QCD. In the end, we will show how these mass effects improve our previous results.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
11
v.
1
no.
2019
63
68
http://ijpr.iut.ac.ir/article_911_2a72220a347681c84fe9c926e966c888.pdf
Searching in GaBoDS deep survey for clusters of galaxies by weak gravitational lensing
M
Rahimi
دانشگاه الزهرا
author
SA
Najafi Shoushtari
پژوهشگاه دانشهای بنیادی
author
S
Ghassemi
پژوهشگاه دانشهای بنیادی
author
MT
Mirtorabi
دانشگاه الزهرا
author
text
article
2019
per
The aim of the present work is detection of galaxy clusters based on weak gravitational lensing method. We apply mass aperture statistics method to 0.32 square degrees data obtained with the WFI@MPG/ESO 2.2 m telescope and detect mass peaks based on their mass not the luminosity. So by the application of proper filter function, shear profile and mass map are produced. Finally mass peaks with higher detection significance are extracted. In future works, redshift of these mass concentrations and so their mass can be obtained.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
11
v.
1
no.
2019
69
77
http://ijpr.iut.ac.ir/article_912_d3c65afe16a406b1b9b5f283486f6f7d.pdf
Polarized electron-muon neutrino scattering to electron and neutrino in noncommutative space
MM
Ettefaghi
دانشگاه قم
author
T
Shakouri
دانشگاه تفرش
author
text
article
2019
per
For neutrino scattering from polarized electron, the weak interaction term in the cross section is significantly suppressed by the polarized term. The magnetic moment term does not receive any correction from the electron polarization. Hence, the study of the magnetic moment of neutrinos through scattering from the polarized electron leads to a stronger bound on the neutrino magnetic moment compared with the unpolarized case. On the other hand, neutrinos which are electrically neutral can couple directly with photons in Noncommutative (NC) QED. In this paper, we calculate the NC QED corrections on this scattering are calculated. The phase difference between the NC term and the polarized weak interaction term is π/2. Therefore, the NC term does not destroy the above suppression.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
11
v.
1
no.
2019
79
85
http://ijpr.iut.ac.ir/article_913_475fa8beec95d4df82625c4e65eb17f0.pdf
PIC simulation of electron acceleration in an underdense plasma
S
Darvish Molla
دانشگاه الزهرا
author
M
Chaboksavar
دانشگاه الزهرا
author
M
Jamshidi
دانشگاه الزهرا
author
MR
Rouhani
دانشگاه الزهرا
author
H
Hakimipajouh
دانشگاه الزهرا
author
text
article
2019
per
One of the interesting Laser-Plasma phenomena, when the laser power is high and ultra intense, is the generation of large amplitude plasma waves (Wakefield) and electron acceleration. An intense electromagnetic laser pulse can create plasma oscillations through the action of the nonlinear pondermotive force. electrons trapped in the wake can be accelerated to high energies, more than 1 TW. Of the wide variety of methods for generating a regular electric field in plasmas with strong laser radiation, the most attractive one at the present time is the scheme of the Laser Wake Field Accelerator (LWFA). In this method, a strong Langmuir wave is excited in the plasma. In such a wave, electrons are trapped and can acquire relativistic energies, accelerated to high energies. In this paper the PIC simulation of wakefield generation and electron acceleration in an underdense plasma with a short ultra intense laser pulse is discussed. 2D electromagnetic PIC code is written by FORTRAN 90, are developed, and the propagation of different electromagnetic waves in vacuum and plasma is shown. Next, the accuracy of implementation of 2D electromagnetic code is verified, making it relativistic and simulating the generating of wakefield and electron acceleration in an underdense plasma. It is shown that when a symmetric electromagnetic pulse passes through the plasma, the longitudinal field generated in plasma, at the back of the pulse, is weaker than the one due to an asymmetric electromagnetic pulse, and thus the electrons acquire less energy. About the asymmetric pulse, when front part of the pulse has smaller time rise than the back part of the pulse, a stronger wakefield generates, in plasma, at the back of the pulse, and consequently the electrons acquire more energy. In an inverse case, when the rise time of the back part of the pulse is bigger in comparison with that of the back part, a weaker wakefield generates and this leads to the fact that the electrons acquire less energy.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
11
v.
1
no.
2019
87
107
http://ijpr.iut.ac.ir/article_914_5e05ef9f17643ef65bc1d4750fb23f57.pdf
One dimension PIC simulation of nonlinear ion-acoustic waves in plasma
A
Kargarian
دانشگاه تربیت معلم تهران
author
MR
Rouhani
دانشگاه الزهرا
author
H
Hakimipajouh
دانشگاه الزهرا
author
text
article
2019
per
In this paper with use of Particle in Cell (PIC) simulation method in one dimension the dynamic of ion acoustic soliton is studied. in this method the ions are monitored as particles and the electrons are assumed to be in thermal equilibrium. The dispersion relation of ion acoustic waves is investigated. The results are in good agreement with analytical results showing that in linear regime our code works correctly. Considering the solution of nonlinear KdV equation as initial perturbation, the propagation of ion acoustic soliton is studied. It is shown that the shape and the velocity of ion acoustic soliton is preserved during propagation through the plasma.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
11
v.
1
no.
2019
109
116
http://ijpr.iut.ac.ir/article_915_db7558bb216f9a93dbfd0f17720f9103.pdf