نشریه پژوهش سیستم های بس ذره ای
سال دهم شماره 2 (پیاپی 25، تابستان 1399)

In this paper, the electrical transport of graphene and silicene nanostructures connected to two semi-infinite graphene and silicene electrodes have been investigated. In these structures, we created nanopores and passed the DNA molecule through the nanopore. Using the Green's Function method and Tight binding approximation, two types of systems with zigzag edges in graphene and silicene have been investigated. By connecting the nanoribbons to the metal electrodes, the created current passes from the nanopore and DNA, from the left to the right. This electric current flow increases the system's sensitivity to the organic DNA bases. We have introduced a new scheme for DNA sequencing.

In this paper we investigate the screening effects of coulomb interaction in monolayer and bilayer C3N and C3NH3 samples based on the random-phase approximation and compared with graphene and hydrogenated graphene. We calculate partially (U) and fully (W) screened, and also bare (V) interaction parameters for these compounds. In the system with more electrical conductivity the effects of the screening are greater and the parameters U and W are further reduced. In monolayer C3N, interaction parameters are similar to those of graphene. The fully hydrogenated C3N is also a relatively large gap in the chair-type and boat-type, and the values of interaction parameters are greater than the monolayer C3N and hydrogenated graphene values.  In the bilayer C3N with metallic behavior, there's a large screening that makes it a correlated system.

The 43Sc radioisotope with a half-life of 3.891 h is an ideal radioisotope for PET imaging. In this paper, the production of 43Sc radioisotope through 43Ca(p,n)43Sc, 44Ca(p,2n)43Sc, 42Ca(d,n)43Sc, 43Ca(d,2n)43Sc, 40Ca(α,p)43Sc and 41K(α,2n)43Sc nuclear reactions have been investigated. The cross-section of these reactions was calculated using the TALYS1.8 and ALICE ASH 1.0 nuclear codes and compared with the experimental results. The SRIM-2013 and MCNPX2.6 codes are used to calculate the stopping power and projectile flux distribution in the target. The theoretical and simulation production yields for each reaction are calculated. The production yield results of some of these reactions are compared with the experimental results at the same optimum energy interval, which shows relatively good agreement between the experimental and computational results.

In this study, according to the observation data obtained through two planck and WMAP satellites, in addition to studying and describing them, we obtain the highest adjustment and correlation between the calculated value and the observation of these data. However, these satellites periodic presentation of data from the universe, which has been modified in relation to previous data, therefore requires comparative and comparative analysis between them, and by determining the coefficient of correlation between them, we can find the best value of each parameter for using in cosmic models. However, By reviewing this article, the following results are obtained:1. The Hubble parameter is presented as the most important factor in determining other basic parameters of cosmology and its values in various articles. According to recent data, the value of this parameter has been obtained over the past 25 years in the range of , but the amount now considered as the most probable data for the current Hubble parameter , The latest announcement by Planck Satellite in 2015, . 2. Different density parameters such as ordinary and dark matter, baryonium, neutrino and dark energy were introduced as another fundamental parameter of cosmology and their methods of determination were investigated. Considering the very different data, the density of ordinary matter And the dark is in the range 0.1 <Ω_m <0.5. Also, the appropriate interval for the baryon density parameter is 0.01 <Ω_b h ^ 2 <0.025. The last values given for the baronic density and cold dark matter and the whole world in 2015 were given by Planck satellite as  and . All quantities given by various papers for the total density of the universe support a value of Ω_0 ~ 1, and this represents the flat cosmology model for our current universe. With respect to this value of Ω_0, the current density of the universe is . 3. The age of the universe was studied as one of the other fundamental parameters of the universe. By summarizing different data, an interval can be drawn for the current age of the world, but according to the latest Planck satellite data, the most likely value for the current age of the world is 13.82 Billions of years. Finally, a comparative analysis was carried out between some of the other important cosmological parameters according to Planck and WMAP data that are used to solve some cosmic problems and astrophysics. This research can be used for any expert who considers astronomy and astrophysics issues as a guidebook for examining cosmic models.

In this paper, synthesis of SnO2/ZnO composite hollow nanofibers using simple electrospinning method is reported. To improve the functional properties of composite hollow nanofibers, a different amount of ZnO precursor is added to the SnO2 precursor used in the solution. The structural and optical properties of produced nanofibers are studied using Scanning Electron Microscope (SEM), X-Ray (XRD) Diffraction, Ultraviolet-Visible Spectrophotometer (UV-Vis) and Fourier Transformed Infrared Spectrophotometer (FTIR). The XRD results show changes in the relative intensity of ZnO and SnO2 peaks with the increase or decrease amount of composite components. The FT-IR spectrum indicates a decrease in the relative band intensity of SnO2 with increasing ZnO in the composite. The UV-Vis spectra also show the flattening of the peaks by adding ZnO. Finally in the studying of photocatalytic properties with different ratios, the ratio of    shows the highest color decomposition, of the order of 62%, in 2 hours under UV irradiation.

Aluminum hydroxide nanoparticles successfully synthesized in an electrochemical cell containing tetramethylammonium chloride as electrolyte and two Al sheets as anode and cathode. In order to study the effect of voltage on crystalline properties of particles, five samples synthesized by applying 7 V, 9 V, 12 V, 15 V, and 18 V. The particles characterized using X-Ray diffraction (XRD) and scanning electron microscope (SEM). XRD patterns clearly approved the formation of aluminum hydroxide with cubic structure and no sign of impurities observed. Based on these results, the sample prepared under 7 V had amorphous structure and the crystal structures of samples improved by increasing the applied voltage. SEM images showed the quasi spherical particles with nanometer size. Based on these images the smallest particles with the mean size of about 9 nm synthesized under 18 V. In the practical part of this study, the removal of nickel and cadmium from water has been investigated by applying 7-18 V on laboratory polluted water and 15 V on Khorram-rood, Kashkan, and Seimareh rivers. The atomic absorption analysis (AAS) results showed the possibility of this method on separation of pollutants from water.

The aim of this study has investigated the removal and reduction of heavy metals such as nickel and cadmium by filtration of modified Nano-fullerene (C60) with tetrahydrofuran. The optimum conditions have been evaluated for the removal of heavy metal ions by nano-adsorbents, which are pH, adsorbent concentration, adsorbent amount, time and temperature. The results show optimum conditions for both ions are almost the same amount. The adsorption of both ions was investigated with the two-oxidation number by adsorption isotherm models. The results show that the best absorption isotherm for Cd2+ is Dobbin-Raduskvich isotherm and for Ni2+ is Freundlich isotherm. The absorption process for both ions is physical, monolayers and exothermic. The data show that the modified nanofullerene has a high thermal and mechanical resistance and is completely stable, which can be used for more than 20 times with high efficiency of %91 without losing its activity.

In this paper, we firstly review some definitions related to fractional calculus and fractional entropy, as a generalization of Shannon entropy. Then we introduce the generalized word importance metric based on fractional entropy. Using the proposed definition, we introduce a new text mining method based on fractional entropy. This method for keyword extraction of the Statistical Inference book by Casella and Berger (1990) shows that the F-measure value of the proposed text mining method, is higher than the related value for common text mining method based on Shannon entropy. These results indicate that the proposed text mining method based on fractional entropy is more comprehensive than the traditional text mining based on Shannon entropy.

In this article, structural stability, electronic and spectroscopic properties of zinc sulfide nanoclusters up to four atoms are studied by Density Functional Theory (DFT/B3LYP) and Hartree-Fock computational level using 6-311++G(d,p) basis set. The stable structures of these nanoclusters have been fully optimized with Gaussian 09, binding energy, energy gap, and FTIR spectra. The vibrational frequencies, Homo–Lumo energy gap, symmetry, and dipole moment are also computed for the most stable isomer of each cluster. Furthermore, NBO analysis was used for deep understanding of these interactions. The reactivity descriptors such as electronegativity are estimated for these nanoclusters to study their relative stabilities. Among nanocluster structures, the highest and lowest average binding length are related to Zn2S2 and Zn1S1, respectively. About stability of investigated structure, Zn4S4 was more stable than others (because stress of nonlinear Zn-S chains is attenuated). Both Zn1S1 and Zn3S3 nanocluster structures have a bigger dipole moment in the Hartree-Fock method. Also, increasing the number of atoms in nanoclusters has increased polarization and in the comparison, Hartree-Fock and DFT in the specimen structures, the polarization of molecules in DFT are larger rather Hartree-Fock.

Weak values of an observable can be found using weak measurements with pre- and post selections for target states. For example, when weak values are small, the expectation value of the pointer position (momentum) shows a shift proportional to the real (imaginary) part of the weak value. In this paper, we introduce the foundations of a new method for obtaining weak values that need not the weakness of the measurement. Using this method, not only the weak values of an observable but also weak values of all powers of the observable can be determined. The key point in this method is that instead of conditional expectation values of the device position and momentum in the standard method we use a complete set of marginal distributions to reconstruct device quantum state.

Today there is a heightened interest in the field of theoretical study of thermoelectric properties due to widespread application of thermoelectric materials. In this research, the Seebeck coefficient (S) and Merit Factor (Z) are calculated for C20-nGen and C20-nSin (n=1-5) bowl structures and the most suitable thermoelectric systems are selected. The quantum calculations are done at the level of LSDA/6-31G of Density Functional Theory (DFT). As the temperature increases from 200k to 400k, the seebeck coefficients of these structures decrease for p-type semiconductors and increase for n-type semiconductors. The maximum values of merit factor are achieved for C19Ge1   equal to 1.78at 278k and for C17Si3 equal to 1.03 at 400k. Therefore, the structures of p-type of C19Ge1 and n-type of C17Si3 with more temperature difference are selected as the best thermoelectric systems. The structures of C20-nGen with n=1,2,5 as the both n-type and p-type semiconductors and C20-nSin with n=3 for n-type and also n=1,3 for p-type have Z>1 and are suitable for thermoelectric systems.

In recent years, modified gravity models have played an important role in the cosmological structures. One of these models is F(R) gravity theory which opened a new insight in the context of black hole thermodynamics. Some of interesting consequences of the black hole thermodynamics resulted into investigation of thermal properties of different black holes. In this paper, first we investigate topological Lifshitz-like black hole solutions of F(R) gravity in d-dimensions and then study thermodynamic properties of such special class of F(R) gravity. Finally, we examine thermal stability and possible phase transition with respect to the heat capacity and Gibbs free energy.