بهروز میرزا

The issue of vacuum, following space, has been of those which has occupied the minds of ancient philosophers and intellectual-philosophical currents of Islamic scientists and physicists since long ago, and different and sometimes contradictory views have emerged in explaining the ontology of space. As the results of a comparative study between modern physics and different philosophical approaches showed that in classical physics, void is possible and physicists are trying to reach complete vacuum. But in the quantum perspective, there are quantum ups and downs caused by the field everywhere, and the world is full, which is consistent with Sadra's view. Of course, it should be noted that there is a difference between the concept of fullness in quantum physics and its concept according to Molla Sadra. Because at the time of Mulla Sadra, the subject of ups and downs and quantum fields was not discussed at all. Therefore, it is necessary to make the ontology of the vacuum in different ways in a comparative way, and in the first step, in this research, this ontology is investigated from the perspective of Sadra and modern physics, and comparative study of other schools in the field would be left to future researches. The current research collects information in a library form and examines it in a descriptive-analytical form.

In this study, the effects of gamma and electron radiation on reflectivity of silver mirrors coated by TiO2 and Ta2O5, in the wavelength range 250 to 1100 (nm) has been investigated. The coatings are considered for space applications in LEO orbit at 500 (km) from the earth surface for three-year mission in space. Electron and gamma dose absorbed within the three-year are respectively about 7.5 (KGy) and 0.4 (KGy) in this orbit. To measure the resistance of TiO2, gamma radiation with CO60 irradiation source was applied on the sample in the range from 0.2 to 20 (KGy) including dose 400 (Gy) at the desired height. At the highest dose, 20 (KGy), radiation effects on both samples were compared with each other. The atomic force microscopy was used to investigate the effect of radiation on the quality of samples surface after radiation, and an spectrophotometer was used to measure the samples reflection before and after radiation. The results showed that in spite of very minor surface changes, and color change of the mirror substrate, its reflection remains unchanged with TiO2 and Ta2O5 coatings.

In this work, different ethyl 2,4-dioxo-4-arylbutanoate derivatives were prepared and evaluated for their Src Kinase inhibitory activity. For this purpose, the appropriate substituted acetophenone derivatives reacted with diethyl oxalate in the presence of sodium ethoxide in dried ethanol to give the corresponding products. All compounds showed moderate activities comparing with staurosporine as the reference drug.

The future singularities are possible in a universe that is described by F (R) theory. In previous studies the occurrence of the singularities in F (R) theory have been considered by using a special function for the Hubble parameter and calculating the F (R) function for each of the singularities. Using the specified Hubble parameter causes some difficulties in the study of the second law of thermodynamics. In this paper by using the scale factor، the behavior of F (R) function near each type of the singularities is considered. We can check the validity of the second law of thermodynamics near the singularities. At first we study the Little Rip and then the other types of singularities are considered. The results show that the second law of thermodynamics is satisfied near the singularity type (I) with some special conditions and is violated with some other conditions. it is satisfied near the Little Rip، type (II)، (III) and (IV) singularities.

In this paper، we considered cosmological constant as a variable and studied properties and the thermodynamics stability of BTZ black hole from a geometric perspective. Also، we examined the correspondence between thermodynamic curvature singularities and phase transitionpoints with different thermodynamic metrics. We found that theQuevedo metric cannot predict the phase transition points in two ensembles. This result is also valid for the kerr-de sitter spacetime.

Interpretation of gravity as entropic force makes some corrections in Friedmann equations. According to calculations of Easson, Frampton and Smooth, the entropic force addss correction terms to Friedmann equations. It’s shown that these corrections change the second type of singularity to the third one in Friedmann equations. Considering Friedmann equations, even without entropic force at least one of the energy conditions is violated in the third kind of singularity. Adding the correction terms, the violated energy condition will change.

In the present paper, we calculate the effect of disorder on the density of states and localization of eigenstates of zigzag and armchair nano-ribbons. Both Anderson disorder model and quantom percolation are considered. The eigenstates of the disordered hamiltonian is calculated in a tight–binding approximation and the localization of eigenstates are characterized using the inverse participation ratio (IPR). Based on IPR data, the transport properties in the presence of disorder is discussed.

The nonlinear Fokker-Plank equations can be related to generalized entropies. We investigate the stationary solutions of Fokker- Plank equations which are related to entropies defined as arbitrary functions of Tsallis entropy. Also the transient solutions of the equations are determined for linaer drifts.

Recently the Jarzynski equation have been under many investigations. In this equation a relation between the average exponential of the work done on a system under non-equilibrium condition and equilibrium free energy differences is established. In different papers the equation has already been extended to different conditions. In this paper we will extend it to a situation that a system is driven away from equilibrium by work performed on it but with a non-constant temperature. Then this generalized equation will be applied to one-dimensional classical and quantum harmonic oscillators.

In this paper a new method is introduced for studying time series of complex systems. This method is based on using the concept of entropy and Jensen-Shannon divergence. In this paper this method is applied to time series of billiard system and heart signals. By this method, we can diagnose the healthy and unhealthy heart and also chaotic billiards from non chaotic systems. The method can also be applied to other time series.

Multiscale entropy (MSE) is a powerful method for determining the complexity of random time series. In this paper we, investigate the cardiac heart interbeat interval (RR) time series by introducing a new method based on MSE, called multicomponent complexity (MCC) and find clear difference between healthy samples and samples with Congestive heart failure (CHF) disease.

Nowadays study of chaotic quantum billiards because of their relation to Nano technology. In this paper distribution of zeros of wave function on the boundary of two circular and stadium billiards are investigated. By calculating gyration radius for these points chaotic and non-chaotic states are distinguished.

In this project, a mathematical model used to study the process of calcium carbonate drying in a co-current spray dryer. In order to determine its performance, the drying kinetics equation obtained using the experimental data. The momentum equation on the suspending particle in air and the differential equations in three dimensions of the particle movement paths and the Reynolds number and the mass and heat transfer coefficients have been solved. Proportional to these relations, a computer program in MATLAB presented. The results obtained from this program predicted the experimental data very well.

We investigate the generation of large scale magnetic fields in the universe from quantum fluctuations that are produced in the inflationary stage. By coupling these quantum fluctuations to the dilaton field and Ricci scalar, we show that the magnetic fields with the strength observed today can be produced. We consider two situations. First, the evolution of dilaton ends by starting the reheating stage. Second, the dilaton continues its evolution after reheating and then decays. We here consider the first case. In both cases, we come back to the usual Maxwell equations after inflation and then calculate present magnetic fields.

We study the phase structure of two dimensional pure lattice gauge theory with a Chern term. The symmetry groups are non-Abelian, finite and disconnected sub-groups of SU(3). Since the action is imaginary it introduces a rich phase structure compared to the originally trivial two dimensional pure gauge theory. The Z3 group is the center of these groups and the result shows that if we use one dimensional irreducible representations (irreps) for group elements the phase diagrams are similar to diagrams of Z3 group. Other irreps with different dimensionality show a little different behaviour for the phase diagram. The phase transition for the Z3 group is first order. The phase structure of the U(N) model is considered and it is proved that it has an infinite number of first order phase transitions.

Our aim in this paper is to find the observable effects of the generalized commutators. For this purpose we investigate two problems in quantum mechanics with minimal length procedure. Firstly, we study hydrogen atom energy levels via minimal length uncertainty relation algebra. From comparing our results, with experimental data we estimate an upper limit for minimal length. Secondly, we investigate statistical mechanics and density of states in phase space via minimal length uncertainty relation and find a correction for white dwarf mass limit. Finally, we study classical implication of minimal momentum uncertainty relations. With this procedure we have corrected the Keplerian third law and some results have been obtained.

A model is proposed to obtain the qq spectra by using a generalized Klein-Gordon equation for a two-body system. A variety of different potentials are coupled to the mass term of the generalized equation. The eigenvalues and the corresponding mass spectra are evaluated by using numerical and analytical methods. The resulting spectra match dosely with the experimental data. The obtained values are also compared with those of models such as quasipotential equation (QPE).