New Research in Physics

Abstract So far, many experiments have been carried out with gamma rays to obtain some information of the matter such as density. The work of Ryabov and others in 1976 is one of these experiments, which was using gamma densitometry to study flooding intervals in a borehole in order to enhance the efficiency of well logging. In this work, simulations have been carried out using MCNP code on soil and sedimentary rocks, and information is obtained about the substance by using flux of back-scattered gamma rays from the material. Since the irradiation of existing sources in nature causes disturbance in measurements, it should be a way to eliminate this disorder, therefore, in this work, the increase in the activity of the source used in simulations in relation to the radioisotopes existing in nature will be proposed, to reduce or eliminate this disruption, which increases the specific activity of the Cs¹³⁷ source relative to the specific activity of the sources in nature and examines the fluctuation fluxes. Using the results obtained in these simulations, it can be deduced that by increasing the special activity of the Cs¹³⁷ source in relation to the radioisotopes existing in nature, the amount of disruptions caused by radioisotopes existing in nature was reduced, until in special activity about 3.09946 MBq/gr this disorder will be close to zero, and it can be said that in a special activity equal to 3.09946 MBq/gr or greater than that, the disorder of radioisotopes existing in nature, can be eliminated to find materials in this way.

Abstract 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.

Abstract The standard model of cosmology, despite its many strong strengths, is constantly under the influence of some serious questions and challenges, and as a result of trying to answer these challenges, new fields and approaches in cosmology were born or developed. Uber's gravitational model, as a new model, is a kind of result of these challenges, which has powerful logic and mathematics. This model, which in recent years has established itself as a seriously modified model, has been able to provide interesting answers to some important challenges. according to the latest estimates, the possible transition of the standard model to this model is approximately estimated at redness Z = 0.54, we decided to test this model through the ISW experimental effect window. With the help of first-order scalar perturbations and numerical solution of density equations, we obtained the ISW signal of the model, which was in the range of 1σ relative to the observations and showed a slight difference from the standard model.

Abstract The minimum-maximum behavior of orbital velocity of a rotating test body around a Kerr black hole is known as the Aschenbach effect. In this paper, we generalize this idea for the charged Kerr black hole(Kerr-Newman) in the de Sitter spacetime to find an indirect measurement of the charge of a black hole or rotating objects same as the other hair of the black hole.

Abstract In this research, RGO-BrInPc nanocomposite was synthesized by chemical reduction of graphene oxide using hydrazine hydrate in the presence of bromoindium phthalocyanine (BrInPc) and sodium dodecyl sulfate (SDS). The results of FTIR and UV-Vis spectroscopy showed that the BrInPc molecules on the RGO sheets are connected by π-π interaction. The electrical properties of RGO-BrInPc nanocomposites were investigated in the temperature range of 298-393 K. Then, several planar interdigital devices with a thickness of 30 nm and a distance between electrodes of 200 μm were fabricated from RGO-BrInPc nanocomposite. The varation of current in terms of temperature at constant 3 V showed that the band gap of RGO-BrInPc nanocomposite changes as a function of the reduction rate of GO in the nanocomposite.

Abstract Recent astronomical observations, show that the universe has an accelerated expansion due to the presence of a kind of energy called dark energy. In this paper, we investigate the effects of quintessence as one of the most acceptable models of dark energy, on thermodynamics of the RN-dS black hole. By using the thermodynamical laws of the black holes and cosmological constant as thermodynamic pressure, we calculate the quantities of temperature, entropy, heat capacity, equation of state, enthalpy, and Gibbs free energy associated with this black hole in the presence of quintessence matter and we analyze the results.