Vol. 65 No. 2 Mar-Apr (2019): Revista Mexicana de Física

In this work, the 5-acetyl-2,4-dimethylthiazole (C₇H₉NSO)  molecule was studied by using the experimental UV-vis (in three different solvents) and FT-IR spectral results and theoretically using DFT calculation method. The calculated molecular geometric parameters, vibrational wavenumbers, HOMO-LUMO energies, ¹H and ¹³C NMR chemical shift values, natural bond orbitals and nonlinear optical properties  of  the 5-acetyl-2,4-dimethylthiazole (C₇H₉NSO)  molecule at the B3LYP/ and HSEH1PBE/6-LanL2DZ  levels of the theory. The spectral results obtained from the quantum chemical calculations of the title compound are in a good agreement with the experimental results. Additionally molecular docking studies were carried out to show vascular endothelial growth factor (VEGFR-2) and β-ketoacyl-acyl carrier protein synthase III (KAS III) inhibitory effect of 5-acetyl-2,4-dimethylthiazole. Molecular docking studies indicated that, 5-acetyl-2,4-dimethylthiazole has potency to be used as an antiproliferative and antibacterial agent.

A variational treatment of the hydrogen atom in its ground state, enclosed by a hard spherical cavity of radius R_c , is developed by considering the ansatz wavefunction as the product of the free-atom 1s orbital times a cut-off function to satisfy the Dirichlet boundary condition imposed by the impenetrable confining sphere. Seven different expressions for the cut-off function are employed to evaluate the energy, the cusp condition, <r^-1>,<r>, <r^2>, and the Shannon entropy, and  as a function of R_c in each case. We investigate which of the proposed cut-off functions provides best agreement with available corresponding exact calculations for the above quantities. We find that most of these cut-off functions work better in certain regions of R_c , while others are identified to give bad results in general. The cut-off functions that give, on average, better results are of the form (1- (r/Rc)^n), n=1,2,3

In this study is determined the thermal conductivity of a commercial ceramic considering that this property on the building materials is an essential factor, and it is the primary indicator of the suitableness of the material in the energy transfer considering that this kind of materials has many applications as thermal insulations. In this sense and considering that a commercial tile is usually composed of three layers, a substrate, a so-called engobe layer, and an enamel layer. Likewise, the thermal properties of the different layers were obtained individually by using two photothermal techniques on the ceramic material; the ceramic tile density was obtained using the Archimedes method. The calculated values show a wide range of thermal conductivity values for the different layers, ranging from1.3 to 4 W m^-1K^-1. 

Many real-life complex networks have in-degree and out-degree distributions that decay as a
power-law. However, the few models that have been able to reproduce both of these properties,
cannot reproduce the wide range of values found in real systems. Another limitation of these
models is that they add links from nodes which are created into the network, as well as between
nodes already present in this network. However, adding links between existing nodes is not a
characteristic available in all systems. This paper introduces a new complex network growth
model that, without adding links between existing nodes is able to generate complex topologies
with in-degree and out-degree distributions that decay as a power-law. Moreover, in this growth
model, the ratio at which links are created is greater than the ratio at which nodes are born, which
produces an accelerated growth phenomenon that can be found in some real systems, like the
Internet at the Autonomous System level.

The physical properties of amorphous indium zinc oxynitride (a-IZON) thin films, which were deposited at room temperature by reactive RF magnetron sputtering, were investigated. The results of the investigations indicated that the a-IZON films possessed excellent qualities: high transparency with a very low resistivity from 10^-3 Ω∙cm to 10^-4 Ω∙cm, while the carrier concentration showed values over 10²⁰ cm^-3 with mobility between 10 and 21 cm²⸱V^-1⸱s^-1. The incorporated nitrogen reduces the typical crystallization of IZO and favors the deposition of transparent thin films. These results show that the IZON is an ideal amorphous material for applications in transparent and flexible optoelectronic devices.

In this work we show through experiments, by using cohesionless granular materials, that a simple formula proposed to estimate the granular outflow from orifices in thick sidewalls is also valid for thin sidewalls. The use of such a formula entails the approximate validity of the classical Hagen and Beverloo formulas for granular samples composed of small and large grains, respectively. Also, an estimation of the involved error when the wall thickness is left aside also is given.

In a previous paper [G.Gomez Blanch and M.J.Fullana, 2017] we dened, in the frame of a geometro-dynamic approach, a metric corresponding to a lorentzian spacetime were the electron stationary trajectories in an hydrogenoid atom, derived from the de Broglie-Bohm model, are geodesics. In this paper we want to complete this purpose: we will determinate the remaining relevant geometrical elements of that approach and we will calculate the energetic density component of the energy-momentum tensor. We will discuss the meaning of the obtained results and their relationship with other geometro-dynamic approaches.
Furthermore, we will derive a more general relationship between the lorentzian metric tensor and the wave function for general stationary states. The electron description by the wave function ψ in the Euclidean space and time is shown equivalent to the description by a metric tensor in an lorentzian manifold. In our approach, the particle acquires a determining role over the
wave function, in a similar manner as the wave function determines the movement of the particle. This dialectic approach overcomes the de Broglie-Bohm model. And furthermore, a non local element (the quantum potential) is introduced in the model, that therefore goes beyond the relativistic locality.

Shell model calculations based on large basis has been conducted to study the nuclear structure of $^{20}Ne$, $^{22}Ne$ and $^{24}Mg$ nuclei. The energy levels, inelastic electron scattering form factors and transition probabilities are discussed by considering the contribution of  configurations with high-energy beyond the model space of sd-shell model space which is denoted as the core polarization (CP) effects.~The Core polarization is considered by taking the excitations of nucleus from the $1s$ and $1p$ core orbits and also from the valence $2s$ $1d$ shell orbit in to higher shells with $4\hbar\omega$. The effective interactions $USDA$ and $USDB$ are employed with $sd$ shell model space to perform the calculation and the core polarization are calculated with $MSDI$ as residual interaction.~The calculated energy level schemes,  form factors and transition probabilities were compared with the corresponding experimental data. The effect of core polarization is found very important for the calculation of $B(C2)$, $B(C4)$ and form factors, and gives excellent results in comparison with the experimental data without including any adjustable parameters.

The elastic scattering of ¹⁷F have been studied for different mass targets (e.g. ¹²C, ¹⁴N, ⁵⁸Ni, ²⁰⁸Pb) at different energies. We used the double folding optical model potential based on the density-dependent DDM3Y effective nucleon-nucleon interaction. Both version of the density distribution of the one-proton halo ¹⁷F nucleus has been taken into account in the above mentioned potential. The data for angular distributions of the elastic scattering differential cross section and reaction cross sections has been successfully reproduced at different energies using the above potentials. The energy dependence and the target mass number dependence of scattering in the imaginary volume integrals and the total reaction cross sections has also been studied.

We study the lateral displacement (Goos-H\"{a}nchen effect) of a Hermite-Gaussian beam incident on a dielectric interface of lower index of refraction than the incident media. Unlike previous results on the same subject, the present result can be applied to an infinite family of higher order solutions (or modes) of the Huygens-Fresnel integral. The final theoretical expression is valid for values that are close to the critical angle $\theta_{c}$. Discussion is made for the behavior of the lateral displacement for different modes of the Hermite-Gaussian beam.

We demonstrate that by focusing in pure water the light of a CW thulium doped fiber laser tuned at a wavelength close to the 1950 nm absorption line of the water and with power of few hundreds of milliwatts, a thermoactivated cavitation bubble formation is obtained. On collapse, a strong ultrasound wave is observed. This effect can be potentially useful for biomedical applications.

In this work, the effect of pore structure of a sandstone on the molecular displacement of confined methane gas is analyzed. It was found that the self-diffusion coefficient of a methane molecule depends on the pore size distribution an their connectivity. In particular, the time dependent self-diffusion coefficient exhibits a maximum which is correlated with the effect of the molecular confinement. It was found that a sandstone with small pores and/or pores bad connected traps the gas more efficiently than other pores structures. This fact enable to understand the scattered values which the residual trapped gas saturation measures exhibit with different sandstones.