Engineering energy gap of the carbon saturated nanowire and investigating the ammonia molecule doping effects by using the initial calculations (Ab initio)
F
marsusi
گروه فیزیک، دانشکده مهندسی انرژی و فیزیک، دانشگاه صنعتی امیرکبیر، تهران
author
S M
monavari
گروه فیزیک، دانشکده مهندسی انرژی و فیزیک، دانشگاه صنعتی امیرکبیر، تهران
author
text
article
2019
per
In this paper size effects, growth orientation and also doping by Ammonia molecule (NH3) on the carbon nanowire properties with saturated diamond structure by (DNw:H) have been investigated. This study was carried out using DFT theory and Kohn-Sham equation by self-consistent field (SCF) that performed by local density approximation (LDA). The nanowires morphology is cylindrical with [111] growth orientation and their lateral surface was saturated by hydrogen atoms. The results show that band gap of these nanowires is smaller to bulk diamond due to high surface to volume ratio and formation surface level. The results of ammonia molecule doping with carbon surface atoms at saturated diamond nanowire in [100] orientation lead to decrease in band gap until nanowire converted into a n-type semiconductor.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
241
248
http://ijpr.iut.ac.ir/article_1434_ff1a9c19530f549ba2c7b46809923b1c.pdf
dx.doi.org/10.29252/ijpr.19.2.241
Investigating the fluctuations of solar and wind energy
M R
Rahimi Tabar
دانشکده فیزیک، دانشگاه صنعتی شریف، تهران
author
A
Madanchi
دانشکده فیزیک، دانشگاه صنعتی شریف، تهران
author
M R
Absalan
دانشکده فیزیک، دانشگاه صنعتی شریف، تهران
author
M
Anvari
دانشکده فیزیک، دانشگاه صنعتی شریف، تهران
author
text
article
2019
per
A time series study of the electrical energy generated by wind turbines and solar cells shows that the energy produced has a lot of fluctuations due to the geographic conditions. These ups and downs have caused not only the share of these sources to be marginal, but also they lead to the volatility of electric power plants. By examining several different data from different countries and regions with the frequency of second and minute, we show that different scale behaviors exist at different time intervals and reveal their other random and nonlinear characteristics. We also compare the non-Gaussian behavior of these regions together, showing that studying the properties of such data helps us to better measure the incidence of these energies
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
249
261
http://ijpr.iut.ac.ir/article_1435_61799dc96892e5d64d0725a6a63e63fb.pdf
dx.doi.org/10.29252/ijpr.19.2.249
Investigation of effect of magnetic ordering on structural and electronic properties of double perovskites Sr2BWO6 (B = Co, Ni, Cu) using ab initio method
T S
Hashemifar
گروه فیزیک، دانشکده علوم پایه، دانشگاه شهرکرد، شهرکرد
author
A
Mokhtari
گروه فیزیک، دانشکده علوم پایه، دانشگاه شهرکرد، شهرکرد
author
text
article
2019
per
Structural and electronic properties of double perovskites Sr2BWO6 (B = Co, Ni, Cu) were studied for each of three magnetic configurations nonmagnetic, ferromagnetic, and antiferromagnetic by using density functional theory in generalized gradient approximations (GGA) and strong correlation correction (GGA + U). Due to magnetic transition from antiferromagnetic to nonmagnetic phase, an electron transition occurred from semiconductor to metal in the tetragonal structure of Sr2CoWO6, and from insulator to metal in the two tetragonal structures of Sr2NiWO6 and Sr2CuWO6. Furthermore, in Sr2CoWO6, another electron transition occurred from metal to half-metal, due to the octahedral rotation of cobalt and possibly because of changes in the magnetic interactions resulting from it. Structurally, the lattice parameters of Sr2CoWO6 and Sr2NiWO6 were decreased by eliminating magnetic interactions. But, the lattice parameters of Sr2CuWO6 was increased with loss of magnetic order, due to the dominance of Jahn-Teller deviation.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
263
272
http://ijpr.iut.ac.ir/article_1436_7aebd7cedfba4b0e160db9be825d25b3.pdf
dx.doi.org/10.29252/ijpr.19.2.263
A simple model for accretion disks in the post-Newtonian approximation
M
Roshan
گروه فیزیک، دانشکده علوم پایه، دانشگاه فردوسی مشهد
author
R
Ranjbar
گروه فیزیک، دانشکده علوم پایه، دانشگاه فردوسی مشهد
author
SH
Abbassi
گروه فیزیک، دانشکده علوم پایه، دانشگاه فردوسی مشهد
author
text
article
2019
per
p { margin-bottom: 0.1in; direction: ltr; line-height: 120%; text-align: left; }a:link { }
In this paper, the evolution of accretion disks in the post-Newtonian limit has been investigated. These disks are formed around gravitational compact objects such as black holes, neutron stars, or white dwarfs. Although most analytical researches have been conducted in this context in the framework of Newtonian dynamics and gravity, it is necessary to consider the effects of relativity on the structure of disks near the central body. To this end, by adding the post-Newtonian corrections to the hydrodynamic equations of the fluids, the equations for the time transformation of the accretion disks at the post-Newtonian limit were obtained; by using this equation, the surface density of the disk, which is dependent on radius and time, is got quasi- analytically. Finally, we compare the time evolution of the accretion disks in Newtonian and post-Newtonian gravity.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
273
283
http://ijpr.iut.ac.ir/article_1437_85e35b3ab4698808dcb16f0a73fc0213.pdf
dx.doi.org/10.29252/ijpr.19.2.273
Radar absorption of FeNi nanoparticles and FeNi@PANI nanocomposites prepared by in-situ polymerization
M
Almasi-Kashi
پژوهشکده علوم و فناوری نانو، دانشگاه کاشان، کاشان،
author
M H
Mokarian
پژوهشکده علوم و فناوری نانو، دانشگاه کاشان، کاشان،
author
S
Alikhanzadeh-Arani
پژوهشکده علوم و فناوری نانو، دانشگاه کاشان، کاشان، دانشگاه فرهنگیان، تهران
author
text
article
2019
per
In this research, FeNi@PANI nanocomposites as the electromagnetic wave absorbers were prepared through two following steps. At first, FeNi alloy nanoparticles were synthesized by the one-pot polyol process, and then, in-situ polymerization method was used for the preparation of FeNi@PANI nanocomposite. The XRD pattern confirmed the formation of pure FeNi alloy with the FCC crystalline phase. The VSM results showed that the saturation magnetization of FeNi@PANI nanocomposite is significantly smaller than that of the FeNi alloy nanoparticles. The microwave absorption was measured in the range of 8 to 12 GHz. The obtained results revealed that the presence of the PANI leads to an increase in the wave absorption of FeNi@PANI nanocomposite compared to that of FeNi alloy. The maximum reflection loss of -4 dB (~ 60% of the loss) and a bandwidth of 350 MHz were measured at -3 dB for the prepared nanocomposite.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
285
290
http://ijpr.iut.ac.ir/article_1438_08c1521610de437f4365f8d0090b6fdc.pdf
dx.doi.org/10.29252/ijpr.19.2.285
Positron annihilation lifetime spectroscopy in nickel ferrite and iron oxide nanopowders
S M
Asgarian
بخش فیزیک، دانشکده علوم، دانشگاه شیراز، شیراز
author
Z
Kargar
بخش فیزیک، دانشکده علوم، دانشگاه شیراز، شیراز
author
text
article
2019
per
In this study, a positron annihilation lifetime spectrometer was set up and its resolution was optimized. The spectrometer is a fast-slow arrangement with time resolution of 250 ps. To obtain lifetime components and their intensities from analyzing positron annihilation lifetime spectrum, the Pascual software is used. Positrons are from a source of radioactive 22NaCl with 20 μCi activity enclosed in 7μm thick Mylar foil. The source correction to lifetime components and their intensities were carried out though measurements on defect-free Aluminum samples and Mylar foils. The positron annihilation lifetime spectrum in nickel ferrite and iron oxide nanopowders were measured. The shortest component was attributed to the annihilation of nonlocalized positrons in the samples. The intermediate lifetime is due to annihilation of positron in octahedral and tetrahedral cationic vacancies in the spinel structure and to annihilation of positrons in the surface of nanoparticles and vacancy clusters. The longest component is attributed to the annihilation of orthopositronium atoms formed in the large free volumes in the intergranular regions of the nanoparticles through ‘‘pick-off” process.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
291
301
http://ijpr.iut.ac.ir/article_1439_9c05c78e220bee9efaa78f8150e1311a.pdf
dx.doi.org/10.29252/ijpr.19.2.291
Study of the effect of particle size on the specific absorption rate of cobalt ferrite nanoparticles in a radio frequency magnetic field
B
Aslibeiki
دانشکده فیزیک، دانشگاه تبریز، تبریز
author
G
Hassanzadeh
دانشکده فیزیک، دانشگاه تبریز، تبریز
author
text
article
2019
per
Studies show that the size of magnetic nanoparticles has an important impact on their properties. So, the possibility of an optimal size for their use in medical applications has been reported. Therefore, in this study, cobalt ferrite nanoparticles were prepared using co-precipitation method at 80°C; then the powder was annealed in a furnace at 150, 200, 300, 400, 500 and 600°C to obtain nanoparticles with different sizes. The X-ray diffraction patterns confirmed the formation of a pure spinel phase in the nanoparticles, and the average size of the crystalites of the samples was determined by Scherrer's formula to be 8.18, 9.04 , 8.95, 9.55, 10.40 and 11.12 nm for synthesized samples at 150 to 600°C, respectively. Measurements of magnetic properties also indicated an increase in the field and the saturation magnetization by enhancing the size. The heat generation efficiency of the nanoparticles suspension was measured by the application of an alternating magnetic field at 92 kHz and the temperature increase curve was calculated versus time. These experiments showed that the highest value of specific adsorption rate for nanoparticles of about 9 nm, and particles larger or smaller than that amount led to a smaller absorption rate. The results of this study, suggest an optimal size for hypertherma applications in which the highest thermal efficiency is achieved.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
303
317
http://ijpr.iut.ac.ir/article_1440_8a7e42a71adafc766f188b03acdbbd86.pdf
dx.doi.org/10.29252/ijpr.19.2.303
Determination of the size distribution of monodesperse and bidisperse mixtures of spherical particles in the nanometer and submicron size range by applying cumulant analysis and contin algorithm in dynamic light scattering
S H
Hooshmand Ziafi
دانشکده فیزیک، دانشگاه شهید بهشتی، تهران
author
M
Dashtdar
دانشکده فیزیک، دانشگاه شهید بهشتی، تهران
author
text
article
2019
per
Determination of particle size is one of the major needs in the industry and biotechnology. Dynamic light scattering (DLS) is a widely used technique for determining size distribution of spherical particle in nanometer and submicron size range. In this method, there are different algorithms for determining the size and size distribution of particles, which are selected according to the required accuracy as well as the sample. In this paper, a review of the theory of DLS and commonly used algorithms to determine particle size, have been carried out. The accuracy and performance range of the two common Cumulant analysis and Contin algorithm have been experimentally investigated, by using the wide range of sizes (20-900 nanometer) of standard spherical polystyrene particles. It is shown that both algorithms results are quite consistent with the manufacturer’s values for diameter of particles. Since most of the samples in the more common situation are not uniform particles with a narrow size distribution, mixtures of two standard particles of different sizes were studied by both algorithms to test the performance of DLS in non-standard samples. Method of Cumulant reports one size that is not consistent with the size of any particles in the sample. However, the polidispersity index (PDI) indicates that the sample size distribution is very wide. Method of Contin reports only one size that is not also consistent with the size of any particles, but, it is closer to the larger one. The results of both algorithms indicate that the DLS fails to determine size distribution in the mixed samples.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
319
330
http://ijpr.iut.ac.ir/article_1441_966cfcf4ca45b1f60d6560d34aeb8ce3.pdf
dx.doi.org/10.29252/ijpr.19.2.319
Half-metallic properties of KP compound in a bulk and (001) surface of rock-salt structure: A b-initio study
P
amiri
گروه فیزیک، دانشکده علوم، دانشگاه شهید چمران اهواز، اهواز
author
H
salehi
گروه فیزیک، دانشکده علوم، دانشگاه شهید چمران اهواز، اهواز
author
M
kazemi
گروه فیزیک، دانشکده علوم، دانشگاه شهید چمران اهواز، اهواز
author
text
article
2019
per
Given the many applications of half-metals in the spintronics devices, we investigated the half-metallic properties of the KP compound in rock-salt (RS) and cesium chloride (CsCl) structural phases by using density functional theory. The results indicated that the KP compound as the half-metal in the RS structure, in contrast to the CsCl structure, due to the small lattice constant and failure of Stoner criterion, did not have any magnetic properties. Half-metallic gap value obtained was remarkable for the RS structure. Although the KP compound in the CsCl structure was more stable than the RS structure energetically, from a dynamical point of view, the RS structure was stable and the CsCl structure was unstable. Calculations corresponding to the (001) surface of the RS structure also demonstrated the conservation of the bulk half-metallic properties in this crystallographic direction. So, the nano-layers of the KP compound in the RS structure might be an appropriate candidate for application in the near future spintronics devices.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
331
339
http://ijpr.iut.ac.ir/article_1442_4e267e2c541baf7c51a0b1da1ed12cde.pdf
dx.doi.org/10.29252/ijpr.19.2.331
Calculation of nuclear level density parameter as a function of tmperature and mass number
M
Nasri Nasrabadi
گروه مهندسی هستهای، دانشکده علوم و فناوریهای نوین، دانشگاه اصفهان، اصفهان
author
text
article
2019
per
Nuclear level density is one of the most important concepts in nuclear physics; basically, it is the key in dealing with nuclear statistical problems. This quantity plays an essential role in the statistical calculation of reactor physics, astrophysics, researches in the average energy of heavy- ion collision and calculations related to neutron evaporation and other applications. This quantity can be calculated analytically by the partition function method and saddle point conditions. Nuclear level density parameter is an important parameter in the calculation of nuclear level density. In this study, this parameter was calculated according to the way in which the limited size of nucleus, continuous states, layer effects, temperature dependence of effective mass related to frequency and momentum and the change of these effects with temperature were considered. To this end, improved Thomas - Fermi approximation as a function of temperature was used. Also, by using this approximation, for continuous effects in the zero temperature, the nuclear level density parameter was calculated as a function of the mass number.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
341
347
http://ijpr.iut.ac.ir/article_1443_3a9c51fdd407f72a3a25690a53cbeb65.pdf
dx.doi.org/10.29252/ijpr.19.2.341
Raman spectroscopy study of nano sheets of graphene and measurement of their resistivity
N
Ghassemi
گروه فیزیک، دانشگاه سیستان و بلوچستان
author
M
Zolfaghari
گروه فیزیک، دانشگاه سیستان و بلوچستان
author
text
article
2019
per
Graphene is a promising candidate for future high-speed electronics applications. It is a thin layer of pure carbon in which every atom is available for chemical reaction from two sides (due to the 2D structure). This is the only form of carbon (or solid material) with this characteristic feature. Graphene oxide (GO) was synthesized through the oxidation of graphite using the Hummer’s method, in which a long oxidation time was combined with a highly effective method for purifying the reaction products. To reduce GO, after the addition of ascorbic acid, the sample was thermally annealed. To verify the structure of GO and G, the transmission electron microscopy images as well as Raman spectra of the samples were obtained. The thickness of the graphene layer was obtained by optical measurement and used to calculate the resistivity of graphene. Rama results showed the D (distorted) mode shifted towards the higher wavenumbers, whereas the G mode shifted towards the lower wavenumbers, with an increase in intensity after the reduction of graphene oxide to graphene.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
349
358
http://ijpr.iut.ac.ir/article_1444_320597cadb916eda286ebb23baf2bf45.pdf
dx.doi.org/10.29252/ijpr.19.2.349
Calculation of the rotational bands for the 20Ne isotope
M R
Shojaei
گروه هستهای، دانشکده فیزیک و مهندسی هستهای، دانشگاه صنعتی شاهرود
author
N
Roshanbakht
گروه هستهای، دانشکده فیزیک و مهندسی هستهای، دانشگاه صنعتی شاهرود
author
text
article
2019
per
The phenomenon of clustering in light nuclei is one of the interesting topics while its study is difficult. In this article, a simple model (the two-particle model which includes a core and a cluster) is presented for the investigation of the positive and the negative parity of rotational bands of 20Ne isotope. The Deng-Fan and the Hellman potentials are considered as the core and the cluster potential. Our results show that the energy levels of the rotational band with positive parities, employing the mentioned potentials, are in a good agreement with those of experimental data. But, in the negative parity rotational band, using the Deng-Fan potential, the corresponding results agree with the experimental data better than those of Hellman potential.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
359
364
http://ijpr.iut.ac.ir/article_1445_1c43469ba2ffafb6fa2a8b142303274a.pdf
dx.doi.org/10.29252/ijpr.19.2.359
Fabrication of single-layer MS2 (M=Mo, W) nanosheets using Li battery setup
M
Zirak
گروه فیزیک، دانشکده علوم، دانشگاه حکیم سبزواری
author
H
Alehdaghi
گروه فیزیک، دانشکده علوم، دانشگاه حکیم سبزواری
author
A
Moshfegh
دانشکده فیزیک، دانشگاه صنعتی شریف، تهران، پژوهشکده علوم و فناوری نانو، دانشگاه صنعتی شریف، تهران
author
text
article
2019
per
Lithium intercalation is a convenient method to prepare few-layer and single-layer MS2 (M=Mo, W) nanosheets. This method is, however, very time-consuming (few days) and it is difficult to control the reaction parameters. To overcome these drawbacks, we have proposed a method to use an Li battery set-up to significantly reduce the reaction time (few hours) and electrochemically intercalate lithium ions into MS2 layers in a controllable manner. Atomic force microscopy (AFM), scanning electron microscopy (SEM) and Raman spectroscopy results revealed that MoS2 and WS2 single-layer (thickness of ~ 1 nm) nanosheets with the 1T phase were prepared after intercalation in an Li battery set-up. Lateral dimensions of MoS2 and WS2 nanosheets were determined to be at about ~ 170 ± 15 and 200 ± 30 nm, respectively. The concentrations of the final solutions containing MoS2 and WS2 nanosheets were measured to be 0.012 and 0.008 mg/mL, respectively. Successful fabrication of the single-layer MS2 nanosheets using the Li battery set-up could provide an excellent opportunity to investigate the unique properties of these two-dimensional crystals for various important applications such as catalysis, solar cells, optoelectronic, etc.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
365
377
http://ijpr.iut.ac.ir/article_1446_e587b154d980a5f715bf049ef8ddf58d.pdf
dx.doi.org/10.29252/ijpr.19.2.365
Gazeau- Klouder Coherent states on a sphere
Z
Heibati
گروه فیزیک، دانشکده علوم، دانشگاه شهرکرد، شهرکرد
author
A
Mahdifar
گروه فیزیک، دانشکده علوم، دانشگاه اصفهان، اصفهان
author
E
Amooghorban
گروه فیزیک، دانشکده علوم، دانشگاه شهرکرد، شهرکرد گروه پژوهشی فوتونیک، دانشگاه شهرکرد، شهرکرد مرکز تحقیقات نانوتکنولوژی، دانشگاه شهرکرد، شهرکرد
author
text
article
2019
per
In this paper, we construct the Gazeau-Klauder coherent states of a two- dimensional harmonic oscillator on a sphere based on two equivalent approaches. First, we consider the oscillator on the sphere as a deformed (non-degenerate) one-dimensional oscillator. Second, the oscillator on the sphere is considered as the usual (degenerate) two--dimensional oscillator. Then, by investigating the quantum optical properties of the constructed coherent states, we study the effect of the space curvature on the properties of the constructed sphere Gazeau-Klauder coherent states, according to these two approaches.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
379
390
http://ijpr.iut.ac.ir/article_1447_0bb98b7deb936303e395d81c65976a58.pdf
dx.doi.org/10.29252/ijpr.19.2.379
The effect of variation of stellar dispersion velocities by the galactic latitude in interpreting gravitational microlensing observations
S
sajadian
دانشکده فیزیک، دانشگاه صنعتی اصفهان
author
S
Rahvar
دانشکده فیزیک، دانشگاه صنعتی شریف
author
text
article
2019
per
Our galaxy is a spiral galaxy and its stars are mostly in a thin disk and rotate around the galactic center. The vertical component of the dispersion velocity of stars is a function of the galactic latitude and decreases with increasing it. In the galactic Besancon model, this dependence is ignored and they just consider the dependence of dispersion velocity on the stellar age. Becanson model is mostly applied to interpret the observational data of gravitational microlensing events to indicate the power index of the power-law number density of mass into the galactic disk. In this paper, we explain that ignoring the dependence of the dispersion velocity on the galactic latitude causes an overestimation of the number of low-mass objects in the galactic disk.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
391
395
http://ijpr.iut.ac.ir/article_1448_bc2f2d1ff0dafe9a0e199dadd174dcf0.pdf
dx.doi.org/10.29252/ijpr.19.2.391
Calculation of the total cross section for the ionization of H, He, Ne and Ar atoms by bare ions at the high energy range
R
fathi
دانشکده فیزیک، دانشگاه شهید باهنر کرمان، کرمان
author
S
amiri
دانشکده فیزیک، دانشگاه شهید باهنر کرمان، کرمان
author
text
article
2019
per
In the present work, the total cross-section for the ionization of H, He, Ne and Ar atoms by +He2+ ، H+ ، Li3 ions has been calculated. In these calculations, a binary encounter approximation in the form of a two-body process between projectile ions and atomic electrons at the high energy range has been implemented. In order to enter the nuclear role of the target atom, the atomic electron velocity distribution function for H, He, Ne and Ar atoms was calculated and the average cross-section was obtained. In these calculations, the Hartree Fock wave functions were used to describe the ground state of He, Ne and Ne atoms. Also, in the calculations related to atomic helium, a single-parameter wave function was used. Finally, the findings were compared with the available experimental and theoretical results.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
397
403
http://ijpr.iut.ac.ir/article_1449_d4d9b19d25f8522168d6703be1a32ca0.pdf
dx.doi.org/10.29252/ijpr.19.2.397
Thermal effect and role of entanglement and coherence on excitation transfer in a spin chain
L
Memarzadeh
دانشکده فیزیک، دانشگاه صنعتی شریف، تهران
author
text
article
2019
per
We analyze the role of bath temperature, coherence and entanglement on excitation transfer in a spin chain induced by the environment. In Markovian regime, we show that coherence and entanglement are very sensitive to bath temperature and vanish in time in contrary to the case of having zero-temperature bath. That is while, finding the last qubit of the chain in excited state increases by increasing the bath temperature. The obtained results show the destructive role of temperature on coherence and entanglement and confirm that these quantum mechanical features cannot affect probability of finding the last qubit in excited state.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
405
413
http://ijpr.iut.ac.ir/article_1450_0af20d9d5e0abd538f18264b881abed2.pdf
dx.doi.org/10.29252/ijpr.19.2.405
Effects of final state interaction in B^+_c to D^0 K^+ decay
B
Mohammadi
گروه فیزیک، دانشکده علوم، دانشگاه ارومیه، ارومیه
author
text
article
2019
per
In this paper, the decay of Bc+ meson, which consists of two b and c heavy quarks, into the Do and K+ mesons was studied. Given that the experimental branching ratio for this decay was within the range of 3.75*10-5 to 11.16*10-5; it was decided to calculate the theoretical branching ratio by applying the final state interaction (FSI) through the T and cross-section channels. In this process, before the Bc+ meson was decayed into two final state mesons of DoK+, it was first decayed into two intermediate mesons like j/ψDs*+; then, these two mesons were transformed into two final mesons by exchanging another meson like Do. The FSI effects were very sensitive to the changes in the phenomenological parameter, which appeared in the form factor relation; this is since in most calculations, changing two units in this parameter makes the final result be multiplied by the branching ratio; therefore, the decision to use FSI was not unexpected. In this study, there were nineteen intermediate states in which the contribution of each one was calculated and summed in the final amplitude. Therefore, the numerical value of the branching ratio of +B+c →DoK decay was obtained by calculating the FSI effects from 1.75 * 10-5to 11.65 * 10-5, which was consistent with the experimental results
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
415
424
http://ijpr.iut.ac.ir/article_1451_630af846068bf4bc1fbac63aab8162d4.pdf
dx.doi.org/10.29252/ijpr.19.2.415
Meson B fragmentation function with consideration of mass corrections
M
Soleymaninia
پژوهشکده ذرات و شتابگرها، پژوهشگاه دانشهای بنیادی، تهران
author
S M
Moosavi Nejad
دانشکده فیزیک، دانشگاه یزد، یزد
author
text
article
2019
per
Study of B meson (meson with the bottom quark flavor) in Large Hadron Collider (LHC) is of special importance so that the detector LHCb is devoted to investigate these types of mesons. For this reason, in this paper we will study the production process of this meson in a phenomenological approach using the experimental data from electron-positron annihilation. In this regards, we shall calculate the fragmentation function of B meson at next-to-leading order of perturbative QCD. We will impose the effect of B meson mass into the calculations for the first time. To perform our analysis, we will employ all available experimental data reported by the OPAL, ALEPH, SLD2002 and DELPHI collaborations. Our results show that the meson mass plays important roles in correction of fragmentation functions, specially, at low values of fragmentation parameter.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
425
435
http://ijpr.iut.ac.ir/article_1452_47f852fbc99326a6c4bcfce6f70a19d7.pdf
dx.doi.org/10.29252/ijpr.19.2.425
Optical properties of a semi-infinite medium consist of graphene based hyperbolic meta-materials with tilted optical axis
sh
rezaei
دانشکده فیزیک، دانشگاه تبریز، تبریز
author
S
Roshan Entezar
دانشکده فیزیک، دانشگاه تبریز، تبریز
author
text
article
2019
per
In this paper, the optical properties of a semi-infinite medium composed of graphen-based hyperbolic meta-materials with the optical axis were tilted with respect to its boundary with air, by using the Maxwell equations; then the homogeneous effective medium approximation method was studied. The results showed that the orientation of the structure layers (geometric induced anisotropy) affected the magnetic transverse polarization spectra in the region, such that the structure exhibited the hyperbolic dispersion. Also, in the large frequency range, in which the medium had hyperbolic dispersion, due to the presence of graphene nanolayer, the transmission of the structure was vanished; by increasing tilt angle of layers with respect to the boundary, it was gradually decreased and finally disappeared
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
437
445
http://ijpr.iut.ac.ir/article_1453_a1e3f64076dcf03e4ff00c6ae5f4528e.pdf
dx.doi.org/10.29252/ijpr.19.2.437
Study of a Restricted Modified Gravity on astrophysical and cosmological scales
Nasim
Derakhshanian
دانشکده فیزیک، دانشگاه تفرش، تفرش
author
Amir
Ghalee
دانشکده فیزیک، دانشگاه تفرش، تفرش
author
text
article
2019
per
p { margin-bottom: 0in; direction: rtl; text-align: right; }p.ctl { font-size: 12pt; }a:link { color: rgb(0, 0, 255); }
In this paper, we study a restricted modified gravity in which diffeomorphism symmetry is broken. We investigate the astrophysical implications of the model by using the corresponding gravitational potential. By using the weight function of the weak lensing , for the model, the deviation of the model with respect to model has been studied for the late-time cosmology.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
447
453
http://ijpr.iut.ac.ir/article_1454_dc5dcc833ee62ebed927caca650301aa.pdf
dx.doi.org/10.29252/ijpr.19.2.447
Singlet scalar dark matter in noncommutative space
Z
Rezaei
دانشکده فیزیک، دانشگاه یزد
author
T
Alizadeh
دانشکده فیزیک، دانشگاه یزد
author
text
article
2019
per
In this paper, we examine the singlet scalar dark matter annihilation to becoming the Standard Model particles in the non-commutative space. In the recent decades, many candidates of dark matter have been offered, but our information about the nature of dark matter is still limited. There are such particle candidates as scalar matetr, fermion, boson, gauge boson, etc.; however, they have neither approved nor rejected. Some complicated models offer many parameters that must be determined. Among these models, the singlet scalar dark matter model is the simplest one that contains just two free parameters to specify. In this paper, we study the singlet scalar dark matter in the noncommutative space, give the scalar dark matter and higgs lagrangian to find their coupling in noncommutative space-time and calculate the cross-section of the scalar dark matter pair annihilation to becoming the standard model particles. It must be noted that there is one extra coupling to explain the dark matter annihilation to becoming the standard model particles in the noncommutative space-time. We investigate the parameter space using the constraint of the thermal average of annihilation cross-section by the velocity. This is the first research on the dark matter annihilation to becoming the standard model particles through the higgs channel in the noncommutative space.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
455
461
http://ijpr.iut.ac.ir/article_1455_a292262f8325572d8f2364c68a28bb99.pdf
dx.doi.org/10.29252/ijpr.19.2.455
Stability of higher derivative modifications of Einstein - aether theory
Z
Haghani
دانشکده فیزیک دانشگاه دامغان، دامغان
author
M
Nedaie
دانشکده فیزیک دانشگاه دامغان، دامغان
author
text
article
2019
per
A time-like unit vector field is used to generalize Einstein's gravity. The resulting theory, called the Einstein-aether theory, consists of a minimal coupling between an aether field and gravity. Inspired by the Bopp-Podolsky electrodynamics, which is well-known for removing the singularity at the point charge, we generalized the Einstein-aether theory by adding such a higher order self-interaction term. We show that the resulting theory can explain the late time accelerated expansion of the universe. We then consider the cosmological perturbation theory on the top of the de Sitter solution and try to answer the question whether an additional Lorentz breaking vector field can cure the small scales instability of the Bopp-Podolsky electrodynamics.
p { margin-bottom: 0.1in; direction: rtl; line-height: 120%; text-align: right; }p.western { font-family: "Times New Roman", serif; font-size: 12pt; }p.cjk { font-family: "Times New Roman"; font-size: 12pt; }p.ctl { font-family: "Lotus"; font-size: 15pt; }
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
463
470
http://ijpr.iut.ac.ir/article_1456_4dc638258fa1aa8887ae8f9dba995df2.pdf
dx.doi.org/10.29252/ijpr.19.2.463
A performance study of the conceptual implementation of the GEM-tracking detector in Monte Carlo simulation
N
Divani
گروه فیزیک، دانشکده علوم، دانشگاه بیرجند، بیرجند مرکز شتابدهنده یونهای سنگین GSI، دارمشتات، آلمان موسسه هلمهولتز ماینس HIM، ماینس، آلمان
author
M M
Firoozabadi
گروه فیزیک، دانشکده علوم، دانشگاه بیرجند، بیرجند
author
T
Saito
مرکز شتابدهنده یونهای سنگین GSI، دارمشتات، آلمان موسسه هلمهولتز ماینس HIM، ماینس، آلمان
author
text
article
2019
per
PANDA experiment (antiProton ANnihilation at DArmstadt) is one of the key projects of the future FAIR facilities to investigate the reactions of antiprotons with protons and nuclear targets. experiment is designed to serve as a completely extraordinary physical potential due to exploiting the availability of cold and high-intensity beams of antiprotons. One of the significant parts of the set-up consists of gas electron multiplayer tracking systems which are under study and construction. A gas electron multiplier GEM is a type of gaseous ionization detector used as the first forward tracking system behind the central tracker in the setup to improve the measurement of charged particle trajectories with a high resolution in the forward direction. This study is concerned with implementing and developing one typical kind of these systems using Monte Carlo simulation based on the conceptual design and investigation of its performance.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
471
478
http://ijpr.iut.ac.ir/article_1457_1805d75a93241abc1616ee1776f1e74d.pdf
dx.doi.org/10.29252/ijpr.19.2.471
Non-thermal atmospheric pressure plasma source design and construction using Argon as the working gas for wound healing
Z
shahbazi rad
دانشگاه شهید بهشتی، دانشکده مهندسی هستهای، گروه کاربرد پرتوها
author
F
Abbasi Davani
دانشگاه شهید بهشتی، دانشکده مهندسی هستهای، گروه کاربرد پرتوها
author
Gh
Etaati
دانشگاه صنعتی امیرکبیر، دانشکده مهندس انرژی و فیزیک
author
text
article
2019
per
In this research, a non-thermal atmospheric pressure plasma jet device was constructed for skin wound treatment. For this reason, five mice were treated for five consecutive days for 30 s, in a daily manner. Natural wound healing time was monitored and compared with the treated one in 12 consecutive days. The measurement of voltage, current and power waveforms of the plasma source, the optical emission spectra of plasma, the reduction of the wound area, and the morphological changes in wounds were studied. The wounds treated with Ar plasma jet were healed sooner than the control wounds, especially in the first days after wounding. Statistical analysis was also done on all treated and control wound reduction ratio values and compared with each other.
Iranian Journal of Physics Research
https://www.psi.ir/physics_society_iran_1_home
1682-6957
19
v.
2
no.
2019
479
487
http://ijpr.iut.ac.ir/article_1458_927290132a8bacc30ec85039c6ef35dc.pdf
dx.doi.org/10.29252/ijpr.19.2.479