Iranian Journal of Physics Research最新文献

{"title":"Electron transport in DNA sequencing connected to silicene electrodes: design of electronic devices","authors":"","doi":"10.47176/ijpr.23.1.81549","DOIUrl":"https://doi.org/10.47176/ijpr.23.1.81549","url":null,"abstract":"In this article, electron transport has been studied for a system consisting of a double-stranded DNA molecule with a telomeric sequence attached to two semi-finite electrodes of silicic nanoribbons. This study has been investigated using the tight-binding model and Green's function approach. By placing the DNA molecule in the middle of two silicon nanorod electrodes, we can see the electron passing channels in the system, and also the type of organic base connected to the electrodes showed a significant effect on the electron transport of the system. Calculations show that telomeric sequences such as TAGGGT, TTAGGG, and GTTAGG have the highest electrical conductivity compared to other sequences. We found that by controlling the gate voltage in the system, It is possible to control the current or load delivery. Also, by increasing the number of organic base pairs in the system, we saw an increase in current, and by controlling the number of organic base pairs, the transport characteristics can be controlled. This ability to control has many uses and a significant role in the manufacture of electronic components.","PeriodicalId":38961,"journal":{"name":"Iranian Journal of Physics Research","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135194509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of thermal diffusivity coefficient of ultrathin metal layers using thermal lens spectroscopy","authors":"","doi":"10.47176/ijpr.23.1.41673","DOIUrl":"https://doi.org/10.47176/ijpr.23.1.41673","url":null,"abstract":"In spite of the incredible evolutions of advanced material characterization methods, this field of research faces different technical and scientific challenges. Thermal lens spectroscopy is known as a sensitive and nondestructive optical based technique to characterize the opto-thermal properties of materials and also to diagnose the impurities in the solutions. In this research, by engaging thermal lens spectroscopy, we investigate the thermal diffusivity coefficient of ultrathin silver layers, prepared by magnetron sputtering. For this propose, the Shen theoretical model is fitted to the obtained empirical signal and subsequently, the thermal diffusivity coefficient will be extracted. The results clearly show that, in the investigated interval thickness (<15nm), the thermal diffusivity coefficient increases by increasing the thickness. Furthermore, our findings reveal that in the very fine thickness region, the thermal diffusivity coefficient shows a fair dependence on the thickness of the silver layers. This might be explained by 2D behavior of the thermal diffusivity for ultrathin metal nanolayers.","PeriodicalId":38961,"journal":{"name":"Iranian Journal of Physics Research","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135194514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effects of random reset on the dynamics of a non-Markovian random walk","authors":"","doi":"10.47176/ijpr.23.1.21612","DOIUrl":"https://doi.org/10.47176/ijpr.23.1.21612","url":null,"abstract":"Resetting in stochastic systems is defined in different ways. In this research, a 1D non-Markovian random walk is considered. In this process, the reset changes the dynamics in a way where the random walker, after losing its memory, goes back to a fixed point in space and starts again. In this study we investigate time evolution and also the long-time limit of displacement moments in the presence of resetting. Our calculations in the long-time limit show that the probability distribution function for displacement reaches a steady-state. On the other hand, this distribution never gets to a Gaussian form for any values of the resetting rate. We will show that, in contrast to the case where the process does not undergo resetting, the moments accumulate to finite values. This is confirmed by doing Monte Carlo simulations.","PeriodicalId":38961,"journal":{"name":"Iranian Journal of Physics Research","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135194518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the damage to the genetic material of the cell induced by protons and carbon ions with the MCDS code compared to the results of the Geant4-DNA Monte Carlo code","authors":"","doi":"10.47176/ijpr.23.1.01584","DOIUrl":"https://doi.org/10.47176/ijpr.23.1.01584","url":null,"abstract":"Due to physical and chemical interactions with the cell DNA, ionizing radiations induce early and late damage to the genetic material. This type of damage, which is mainly caused by single-stranded and double-stranded breaks in DNA, and if not repaired by the cell, can lead to genetic mutations or cell death. In this research, the DNA damage of living cells, induced by protons and carbon ions, which are of great importance in radiation therapy studies, has been investigated with the MCDS code. In order to check the accuracy of the MCDS code results in this research, the probability of each type of damage and the yields have been calculated and compared with the results of previous works with Geant4-DNA. The results of this research, especially double-strand breaks, are very close to the results calculated with the Geant4-DNA code. There are also differences in the results due to the difference in the cross-sections of the two codes, especially in ionization and excitation interactions, as well as the reaction rates of chemical radicals. The results of this research regarding the efficiency of double-strand breaks can be very useful in the planning of treatment with protons and carbon ions.","PeriodicalId":38961,"journal":{"name":"Iranian Journal of Physics Research","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135194768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the giant magnetoresistance in a two-dimensional square network including two materials with a diagonal boundary","authors":"","doi":"10.47176/ijpr.23.1.71531","DOIUrl":"https://doi.org/10.47176/ijpr.23.1.71531","url":null,"abstract":"Large magnetic resistance has been widely considered due to its many applications in various fields, including the manufacture of magnetic sensors. An important case of this type of resistance is the linear magnetoresistance caused by the inhomogeneity of charge distribution. The magnetoresistance of heterogeneous conductors is simulated by the two-dimensional resistance network model. In the network model, the resistance unit of a homogeneous circular disk with four current terminals and the potential difference between the terminals is considered, and the currents and potential differences are connected to each other by means of the impedance matrix, and the magnetic field is perpendicular to the lattice. In this work, we study and investigate the changes in magnetoresistance for a network including two subsystems with different resistances with a diagonal arrangement. The results show that the changes in the magnetic resistance of the heterogeneous system depend on the resistance ratio of the two materials as well as the location of the boundary between them. In addition, it was observed that for large values ​​of the resistance ratio or high inhomogeneity, there is the possibility of the existence of a peak of resistance variation.","PeriodicalId":38961,"journal":{"name":"Iranian Journal of Physics Research","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135194503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of isotopic yield and half-life of spontaneous fission for two (_ 104^266)Rf and (_104^268)Rf superheavy isotopes","authors":"","doi":"10.47176/ijpr.23.1.01588","DOIUrl":"https://doi.org/10.47176/ijpr.23.1.01588","url":null,"abstract":"Isotopic yields and half-lives for (_ 104^266)Rf and (_104^268)Rfisotopes of the superheavy nucleus Rutherfordium are calculated and compared with the experimental data. For each fragmentation, the probability of tunneling through the fission barrier and the fission decay constant are obtained using the WKB approximation. Then, by summation over all partial fission constants, total fission constant and half-lives of two isotopes are obtained. In order to calculate the fission barrier, proximity nuclear and Coulomb potentials are considered (because of even-even isotopes, their ground state spin is zero, so centrifugal potential becomes zero.). The fission barrier as a function of fragment mass number is plotted for two isotopes. Usually, spontaneous fission occurs in superheavy nuclei in such a way that the excitation energy of the parent nucleus is low and therefore the number of neutrons emitted along with the fission is small and can be ignored. Therefore, in this method, which is known as cold spontaneous fission, instantaneous emission of neutrons along with fission is ignored. Isotopic yields of (_ 104^266)Rf and (_104^268)Rf for all possible splitting indicated that the production of two fragments (_ 52^134)Te and (_52^132)Te have the highest partial yields for fission of (_ 104^266)Rf and (_104^268)Rf isotopes, respectively. The existence of a small difference between the calculated and measured half-lives confirms the relative success of our method. .","PeriodicalId":38961,"journal":{"name":"Iranian Journal of Physics Research","volume":"123 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135194512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Annealing temperature effect on optical properties of cadmium telluride thin films","authors":"","doi":"10.47176/ijpr.23.1.81554","DOIUrl":"https://doi.org/10.47176/ijpr.23.1.81554","url":null,"abstract":"Cadmium telluride nanoparticles (CdTe NPs) were deposited by the thermal evaporation method on glass substrates at a temperature of 373 K and a vacuum pressure of 2.7 mPa, and thin films with the thickness of 100 nm were fabricated. The prepared films were subjected to ultraviolet-visible (UV-Vis) spectroscopy to study the optical properties of thin films. To investigate the effect of annealing temperature on the optical properties of cadmium telluride thin films, these films were annealed at temperatures (323-373) K. The light absorption spectra of films before and after annealing were recorded using UV-Vis spectroscopy at a wavelength range of 600-1600 nm shows that the value of light absorption by films increased with the increased annealing temperature. The optical energy bandgap of the grown films has a decrement process from 1.519 eV after annealing. The results of the Tauc plot show the decrease in energy bandgap with annealing. Extinction and refractive indices increase with increment of photon energy and annealing temperature. The relative density and electronic polarizability of grown films increase after annealing. Other optical parameters obtained in this work, including the real and imaginary parts of the dielectric constant, increase, while the surface and volume energy loss functions decrease with increase of the annealing temperature. The results of this work indicate that the deposited cadmium telluride thin films annealed at 373 K have better optical properties for photoelectronic applications.","PeriodicalId":38961,"journal":{"name":"Iranian Journal of Physics Research","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135194774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theoretical study of helium atom single ionization by bare carbon ions impact","authors":"","doi":"10.47176/ijpr.23.1.21647","DOIUrl":"https://doi.org/10.47176/ijpr.23.1.21647","url":null,"abstract":"In this work, the single ionization of helium atoms from the ground and the first excited state by bare carbon ions () impact at the incident energy of 100 MeV has been studied. The post form of CDW-4B formalism is used in the calculations. The correlated Silverman wave function as the ground state of the helium atom has been used to consider the effects of static electron correlation. The results, as the fully differential cross section in the azimuthal plane for different angles and the ejected electron energy 6.5 eV and momentum transfer 0.75 a.u, are compared with experimental and three-body formalism results from theory. Also, the variations of the fully differential cross section in the scattering plane for the various ejected electron energies and momentum transfers have been studied.","PeriodicalId":38961,"journal":{"name":"Iranian Journal of Physics Research","volume":"329 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135194513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"verification of proton range in proton therapy using conversion of PGT spectrum to prompt γ-ray emission profile","authors":"","doi":"10.47176/ijpr.23.1.71532","DOIUrl":"https://doi.org/10.47176/ijpr.23.1.71532","url":null,"abstract":"One of the on-line range verification techniques in proton therapy is time -of-flight (TOF) measurement for prompt gamma. In this technique, the prompt gamma timing spectra is measured using the time difference between passage of the particle bunch through the target entrance of the beam and the arrival time of the corresponding prompt γ-ray at the detector.In this study, homogeneous PMMA phantom and PMMA phantoms with a slice of bone or air cavity were simulated in GEANT4 simulation. These targets were irradiated with a proton pencil beam with an initial energy of 150 MeV, and the resulting PGT spectra was recorded by scintillation detectors.Then, a code was programmed in MATLAB software to analytically solve the kinematics of proton movement in the phantom, and the PGT spectrum obtained from GEANT4 was given as an input to this software code and the prompt gamma-ray emission profiles was obtained in the phantom. In this study, the effect of the type and position of the heterogeneous slice on the PGT spectrum and the prompt gamma-ray emission profiles resulting from the PGT transformation was investigated. From the comparison of the prompt gamma-ray emission profile resulting from PGT spectra conversion, with the energy deposition spectra resulting from GEANT4 simulation, it was observed that the range shift and the shift of energy deposition location resulting from an inhomogeneity in PMMA have a significant relationship compared to the reference phantom.The presence of an inhomogeneous slice of bone and air cavity with a thickness of 10 mm shifts the range of the proton compared to its range in the reference phantom by 4 mm and 9.6 mm, respectively, and the spectra of energy deposition for these states are respectively 4.8 mm and 9.9 mm shifted relative to the energy deposition spectra of the reference phantom. Therefore, the PGT spectra reflects the proton transit time in the target material and provides the possibility of determining the prompt gamma-ray emission profiles and the possibility of confirming the delivery of the dose to the patient's body.","PeriodicalId":38961,"journal":{"name":"Iranian Journal of Physics Research","volume":"292 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135194770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The bulk flow in uLCDM and XCDMand the Hubble constant and sigma8 tensions","authors":"","doi":"10.47176/ijpr.23.1.31667","DOIUrl":"https://doi.org/10.47176/ijpr.23.1.31667","url":null,"abstract":"The standard model of cosmology,, has been successful in describing many observations. With the improvement of the number and the accuracy of observations, some inconsistencies among key cosmological parameters of the model have emerged. Many alternative models are proposed to alleviate these tensions. On the other hand, some observations of peculiar velocity show higher values than expected in a universe which may contradict the cosmological principle. In this work, we used linear perturbation theory to measure bulk flow and parameter in two alternative cosmological models and XCDM. We compared measured bulk flows with the predictions and some observations. We did a analysis to see which model is preferred by data. We find that model predicts higher bulk flows and is more consistent with observational data but does not reduce tension. Bulk flows measured in the XCDM model are lower compared to . However, this model can reconcile tension.","PeriodicalId":38961,"journal":{"name":"Iranian Journal of Physics Research","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135194505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}