The normal state resistivity of CaTh- and La-doped Y(Nd)-123 superconductors in the bipolaron model S. Ghorbani author A. Rostamabadi author text article 2019 per Polycrystalline samples of Y1-2xCaxThxBa2Cu3O7-δ (with 0.00 ≤x ≤ 0.075) and NdBa2-xLaxCu3O7-δ (with 0.0≤x≤ 0.30) were prepared by the standard solid state method. The transport and superconducting properties have been studied by the resistivity measurements as a function of temperature and doping concentration. Data of resistivity as a function of temperature was analyzed in terms of the bipolaran model. The model well described resistivity data up to near the critical temperature. Obtained results suggested that the hole localization is the main reason for superconducting suppression in the charge neutral doped cuprates and the La doped Nd-123 in addition charge filling. Iranian Journal of Physics Research Isfahan University of Technology, The Physics Society of Iran 1682-6957 7 v. 4 no. 2019 189 195 https://ijpr.iut.ac.ir/article_596_e1379fbdd52eb56e3c8e72f62b78a5fd.pdf The structure of invasion percolation clusters in two dimension Z. Daadi-Geev author M. Khaksefidi author F. Ebrahimi author text article 2019 per   We have performed extensive numerical simulations to estimate the fractal dimension of the mass and also the anisotropy in the shape of sample spanning cluster (SSC) in 2-D site invasion percolation processes with and without trapping. In agreement with the most recent works, we have observed that these two different processes belong to two different universality classes. Furthermore, we have determined for the first time, the degree of anisotropy in the shape of SSC by evaluating its gyration ratio. It is found that despite isotropy of the media and also the dynamics, the shape of invasion percolation clusters are not isotropic. The degree of anisotropy is more for clusters of invasion percolation with trapping. We have also studied the distribution of invaded pore sizes for the two invasion percolation processes. Iranian Journal of Physics Research Isfahan University of Technology, The Physics Society of Iran 1682-6957 7 v. 4 no. 2019 197 203 https://ijpr.iut.ac.ir/article_597_923f586e11fdfa2b4b42e6866696a1c3.pdf Correlation between surface microstructure and optical properties of porous silicon Saeideh Rhramezani Sani author Abdollah Morteza Ali author text article 2019 per   We have studied the effect of increasing porosity and its microstructure surface variation on the optical and dielectric properties of porous silicon. It seems that porosity, as the surface roughness within the range of a few microns, shows quantum effect in the absorption and reflection process of porous silicon. Optical constants of porous silicon at normal incidence of light with wavelength in the range of 250-3000 nm have been calculated by Kramers-Kroning method. Our experimental analysis shows that electronic structure and dielectric properties of porous silicon are totally different from silicon. Also, it shows that porous silicon has optical response in the visible region. This difference was also verified by effective media approximation (EMA). Iranian Journal of Physics Research Isfahan University of Technology, The Physics Society of Iran 1682-6957 7 v. 4 no. 2019 205 211 https://ijpr.iut.ac.ir/article_598_e444d0dc9759a665f704501edc658964.pdf The effect of AgNO3 concentration on formation of Ag nanoparticles in Sol-Gel derived Ag-SiO2 thin films A Babapour author L Samii author O Akhavan author A R Moshfegh author text article 2019 per   In this investigation, Ag-SiO2 thin films with different concentrations of Ag (0.2, 0.4, 1.6 and 8%) has been fabricated on soda-lime glass substrate using sol-gel method. After an annealing process, physical and chemical properties of the deposited silica films containing Ag nanoparticles have been studied including optical, topographical structural, morphological and size of the nanoparticle as well as their distribution using UV-visble spectrophotometery, atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques, respectively. Based on our data analysis, the Ag nanoparticles did not form in the samples with low (0.2%) and high Ag concentrations (8%), without any suitable annealing process. Instead, the nanoparticles were formed easily for the intermediate Ag concentrations. In fact, for the the low and high Ag concentration, the Ag nanoparticles formed at the annealing temperature of 200 º C. In addition, according to TEM observations, the minimum average size of the synthesized particles were determined about 4 hm for the thin films containing 0.2% Ag concentration. Iranian Journal of Physics Research Isfahan University of Technology, The Physics Society of Iran 1682-6957 7 v. 4 no. 2019 213 218 https://ijpr.iut.ac.ir/article_599_dd411d592d4621e8d70f73e45cf5cbf9.pdf Shape invariant potentials in SUSY quantum mechanics A. Dadkhah author M. Haghighat author text article 2019 per   We give a brief review on the known shape invariant potentials. We derive the all of them by introducing a general superpotential with two constant and four variable parameters. Finally we examine those potentials which lead to the equally-spaced energy spectrum for the Klein-Gordon equation. Iranian Journal of Physics Research Isfahan University of Technology, The Physics Society of Iran 1682-6957 7 v. 4 no. 2019 219 226 https://ijpr.iut.ac.ir/article_600_a7280b13cb1384ffc70d214e19cd02ac.pdf Investigation of the role of N on the optical efficiency of InGaNAs nanostructures for usage on the optoelectronic industry and optical telecommunication Hamid Haratizadeh author Maryam Gholami author text article 2019 per   Recently, the quaternary InGaAsN alloy system has attracted a great deal of attention due to its potential application in devices such as next generation multi-junction solar cells and optoelectronic devices for example laser diodes for optical communications in IR region. In this paper, we have investigated the role of nitrogen on the improvement of optical efficiency in InGaNAs nanostructures by photoluminescence spectroscopy. These characterizations are because of variation of InGaNAs band structure due to existence of nitrogen, and could be explained by using band anticrossing model which is a result of interaction between the extended conduction band of the InGaAs matrix (EM) and the nitrogen-related localized level (EN). The band-gap of InGaNAs is very sensitive to the nitrogen content, so it has decreased by increasing of nitrogen content. Therefore accessibility to emission light wavelength at IR region is controllable. Moreover, nitrogen has created the potential fluctuations in the InGaNAs so it is the cause of trap centers that leads to localized excitons. Thus the probability of exciton recombination has increased and improved optical efficiency of these structures. But in other cases, nitrogen has made fluctuations especially in the common surface of the well and barrier in InGaNAs quantum structures so they increase non-radiative recombination. Iranian Journal of Physics Research Isfahan University of Technology, The Physics Society of Iran 1682-6957 7 v. 4 no. 2019 227 234 https://ijpr.iut.ac.ir/article_601_793836881d63576778411bc4b838cbb3.pdf Nuclear charge distribution of fission products originated from fission of 238U nuclei induced by45-69 MeV protons Houshyar Noshad author text article 2019 per  Fission of 238U nuclei was performed by 45-69 MeV protons at the Cyclotron and Radioisotope Center of Tohoku University in Japan. The fission products originated in the reaction were identified by using gamma spectroscopy. The experimental data show that the charge distribution of isobar fission products follows a Gaussian distribution with a standard deviation independent of the selected mass number. The standard deviations were measured for the reaction 238U(p, f) with 45, 55, 65 and 69 MeV protons. For Ep < /sub> = 45 MeV, the standard deviation obtained from the experiment is in agreement with the existing data and satisfies the prediction of the Hauser-Feshbach statistical model. For other proton energies, measurement of this quantity has not been reported in the literature. The experimental results show that the value of standard deviation increases, when the excitation energy of the fissioning nucleus increases. Furthermore, the most probable charge was determined for the isobar fission products detected in the experiment. The results are consistent with the prediction of the minimum potential energy (MPE) model. Moreover, the experimental data show that nuclear charge polarization occurs in the fission process. Iranian Journal of Physics Research Isfahan University of Technology, The Physics Society of Iran 1682-6957 7 v. 4 no. 2019 235 241 https://ijpr.iut.ac.ir/article_602_fde603d5f4476cf6d5ed92e7e506ebef.pdf Investigation of particle size on the phase formation and microstructure of Bi-2223/Ag wire H. Salamati author P. Kameli author I. Abdolhosseini author H. Ahmadvand author text article 2019 per   The effect of particle size and the heat treatment on precursor powder and subsequent phase formation of silver tube Bi-2223 wire has been studied. First, we have prepared a series of Bi1.66Pb0.34Sr2Ca2Cu3Oy samples with different sintering temperatures and studied the phase formation in these samples. Second, different particle size distributions were obtained by grinding powders of best formed Bi-2223 phase samples. PIT technique has been used to make wires of Bi-2223 phase using silver tube. The effects of precursor heat treatments and different particle size were identified by combination of XRD, SEM EDX, LPSA (Laser Particle Size Analyzer) electrical resistivity and Ac-susceptibility measurements technique. It has been shown that the small particle size promotes the formation of Bi-2223 phase and the critical current densities tend to increase when the size of sintered powder of Bi-2223 phase used in the formation of wire, decreases. Iranian Journal of Physics Research Isfahan University of Technology, The Physics Society of Iran 1682-6957 7 v. 4 no. 2019 242 242 https://ijpr.iut.ac.ir/article_603_a132a4c2d043196caa4bbdc815c065ee.pdf