فهرست مطالب hadi sabri

The correlation of different samples can be described by analytical models such as random matrix theory. In this study, we tried to describe the correlation of different types of ultraviolet values in different months, weeks, and hours to get a significant relationship of special times, which one needs to get enough intensity of the sun or avoid getting sunburn.

To this aim, we focused on the hourly and daily mean amounts of ultraviolet A, B, and C intensities of solar radiation in Tabriz urban area were measured during a full year of 2017-2018. We used such ultraviolet values which are measured at the same hour of the day to satisfy the same symmetry criteria which are necessary in random matrix theory. These data are unfolded and classified in different sequences to analyze in the nearest neighbor spacing distribution framework via the maximum likelihood estimation technique.

Strong correlation is yielded for daily values of UVA in comparison with the other types of ultraviolet radiations. Also, we considered the dependence of correlation degrees of these three types of ultraviolet to average temperature and humidity at different months.

The results propose more correlation of UVA indices in August while such correlation of UVC radiations are yielded in December.

In this paper, the statistical properties of 1- to 7- negative parity levels in the 170Tm nucleus are considered with emphasis on the nearest neighbor spacing distribution in the framework of random matrix theory. The latest available experimental data for different negative parity energy levels in the E≤  3000 keV region are used to classifiy in different sequences and are analysed. The Berry – Robnik distribution function and the least square extraction method have been used to determine the parameter of distribution function in considered sequences. The results 
show the adaptation of the statistical behavior of all considered negative parity levels with the Wigner distribution function and therefore, the statistical correlation of such levels. Also, the strong correlations are yield for the sequences prepared by levels with odd spin values while the 2- levels show a weak correlation and a Poisson-like behavior. The dependence of the statistical behavior of the negative parity levels to the energy was investigated which suggests the maximum correlation in the 1300  <E < 2100 keV energy region.

In this study, the statistical correlation of the electric quadrupole transition probabilities in the spherical nuclei is investigated. To this aim, the spherical even-even nuclei in the 100 < A < 126 mass region are selected and the electric quadrupole transition rates of different levels in the ground band are determined by the interacting boson model in the U(5) dynamical limit. A non-parametric kernel density estimation method is used in the framework of nearest neighbor spacing distribution of random matrix theory to consider the statistical correlation of these quadrupole transition rates. Also, the Kullback-Leibler divergence is used to describe the regular or chaotic behavior of the considered sequences. The results show the correlation of the electric quadrupole transition probabilities between different levels of the ground band. Also, the correlation increased for such transitions that the angular momentum of the initial state of quadrupole transitions increased.

The electric quadrupole transition probabilities of 98-104Ru isotopic chain are investigated in the both shell and interacting boson models frameworks. The OXBASH code for shell model and the SU(1,1)-affine infinite dimensional algebra for interacting boson model are used to determine the quadrupole transition rates. Also, the dependence of calculation accuracy and the effective charges to quadrupole deformation and experimental half-lives are considered and the quadrupole moments are computed for these nuclei. The shell model make exact results for such nuclei which are located near the closed shell and also verified the existence of closed sub-shell at N=58 neutron number. On the other hand, the interacting boson model make more exact results for nuclei which have signatures of deformation and also the quadrupole intra-band transition rates. The results suggest a shape coexistence in the 102Ru nucleus.

In this paper, the 180-188Hg isotopic chain is studied in the transitional region between the prolate and oblate shapes. To this aim, we have used a two parametric transitional Hamiltonian in the interacting boson model. With using Catastrophe theory in combination with coherent state formalism, we have determined the energy surfaces in this transitional region. The results of this study for energy levels and quadrupole transition probabilities are in the satisfactory agreement with experimental counterparts. Also the results for the control parameter of transitional Hamiltonian and the variation of energy surfaces propose a first order phase transition in this isotopic chain and suggest 188Hg nucleus as the best candidate for the O(6) dynamical symmetry limit or Z(5) critical point symmetry.

In this paper, we have considered the energy levels and energy surfaces of nuclei located between the spherical and the gamma soft shapes. We have used a three levels spd-interacting boson model which are defined in the affine SU(1,1) algebra to describe both positive and negative parity states. The energy surfaces of 100-106Ru isotopes are determined via catastrophe theory and coherent states formalism in the U(5)-SO(9) transitional region of interacting boson model. The agreement between the theoretical prediction of model and the most recent experimental counterparts is acceptable. Also, the variation of the energy surface’s shapes suggest a second order shape phase transition in this isotopic chain. The values of the control parameters and also the shape of energy surfaces suggest 100Ru as the best candidate for the critical point of this transitional region.

In this paper, we have studied the spectral statistics of 101 even-even nuclei in the nearest neighbor spacing distribution framework. Sequences are prepared by using all the latest experimental data for 2 levels of considered nuclei in the 40 ≥ A≥198 mass region. The maximum likelihood estimation technique has been used to extract the Berry-Robnik distribution’s parameter which explores the regular or chaotic behavior of considered sequences. Sequences are classified as their mass, quadrupole deformation parameter, the energy ratio and the shell model configuration for the last protons and neutrons of all nuclei. Our results suggest a regular dynamics for these even mass nuclei. Also, the regularity is increased for light nuclei vis-a-vis heavier ones and also the deformed nuclei vis-a-vis spherical ones. Our results show a deviation of chaotic dynamics when the spins of proton levels are decreased or the spins of neutron levels are increased.